History Podcasts

Metallised Strips

Metallised Strips

In 1942 scientists in Britain developed an idea that they believed would confuse Germany's radar system. Given the codename of Window the strategy involved the Pathfinder Force dropping strips of metallised paper over the intended target. By early 1943 a series of tests had shown Bomber Command that Window would be highly successful. However, the British government feared that once the secret was out, the Germans would use it to jam Britain's radar system. It was not until July 1943 that permission was finally given to use Window during the bombing of Hamburg.

Window was a great success and was employed by the RAF for the rest of the war. The Germans were forced to change its strategy in dealing with bombing raids. As Air Marshall Arthur Harris later pointed out: "The Observer Corps now plotted the main bomber stream and orders were broadcast to large numbers of fighters with a running commentary giving the height, direction and whereabouts of the bomber stream, and of the probable target for which it was making or the actual target which it was attacking."

The main objection to the use of "Window" (the strips of metallised paper) which proved to be the most important and effective of all the weapons used against enemy radar, continued to be the fear of its effect on our own defences. It was hoped that our own radar would be developed to the point where the strips

of paper would not cause any very serious interference, but even so, defensive radar might never be quite so effective after its introduction as before. When I continually pressed for the introduction of this weapon, other objections were also made. It appeared that we were short of suitable plant for the manufacture of the strips in quantity, and that it would be very difficult to get priority for the supply of aluminum needed. There can be little doubt that if we had been able and allowed to use this weapon in the first months of 1943 we should have saved hundreds of aircraft and thousands of lives and would have much increased the accuracy of our bombing.

There was every reason to believe that if the authorities would only allow us to drop strips of metallised paper during our attacks we should hopelessly confuse the enemy's radar on which he relied for the control of his night fighters and the accuracy of his gunfire. Early in 1943 there had already been developed a suitable form of this weapon for jamming the enemy's ground control stations, radar-sighted guns, and airborne radar for interception. And we had already worked out the quantity of strips of paper that would be required, the rate at which it should be dropped, and the areas over which it should be released. It cannot be said that there was ever an occasion when we did not need to use this weapon, but we needed it as much as ever before at the end of July, 1943, and it was just at that time that the Air Ministry after I had urged the use of this weapon at repeated intervals for many months, decided that it was now possible to accept the risk of the enemy using the same weapon against our own defences. The strips of paper-they were given the code name "Window" - were dropped for the first time on the night of July 24th-25th. The target was Hamburg, beyond Oboe range.

No air raid ever known before had been so terrible as that which Hamburg had endured; the second largest city in Germany, with a population of nearly 2,000,000, had been wiped out in three nights. And at the same time the whole system of air defence, carefully built up, at the expense of all the other battle fronts in which the Germans were fighting, over a period of years, had been thrown into utter confusion; the night fighters, it appeared, would in future be powerless to detect the bombers in the dark, and the guns and searchlights would be altogether inefficient. The first type of Window used by Bomber Command in the attacks on Hamburg was designed to confuse the enemy's Wurzburgs, used both for ground control of fighters and for gun laying, and we knew at once that it had been successful in this. But the enemy also knew what we discovered later, that Window seriously interfered with the night fighters' airborne radar as well.

Chapter2 "This is The Product We Must a Produce"

Due to its business connections with the Occupation Forces, Totsuko decided to work on a magnetic sound recorder.
Masaru Ibuka had always wanted to produce something that would directly benefit the general public, who's needs were quite different from the government and other institutional customers. But it was not just any product that Ibuka wanted. Radios had already been introduced by large companies. Akio Morita was then also looking, purely from a business point of view, for a product with which Totsuko could expand its sales channels beyond NHK. It was then that the wire recorder caught the attention of both Ibuka and Morita.

The Totsuko engineers acted quickly once they had made up their mind and research got under way immediately. Masanobu Tada of Nipon Electric Co.(NEC Corporation) was kind enough to bring in a wire recorder unit, saying, "You might find this interesting." It had been used by the Japanese Army during the war. Totsuko disassembled the unit at once and studied its recording and playback mechanisms. Around the same time, a friend in the United States gave Morita a Webster's recorder kit that used stainless steel wire. The kit had a simple reel winding mechanism with a recording head. It was Nobutoshi Kihara(now President of Sony-Kihara Laboratory) who completed the kit assembly with an amplifier. The first thing they recorded was NHK's news broadcast of a Japanese swimmer Hironoshin Furuhashi setting a new world record at an all-American aquatic championships meet at Los Angeles.

Incidentally, Kihara had been one of Ibuka's students in the electricity course at the Mechanical Engineering Department of Waseda University. Prior to graduation, Kihara noticed a Totsuko help-wanted ad at the school. Out of fun and curiosity, Kihara went for an interview, the only form of employment examination at the time. His resume listed special skills related only to electricity and stated, "I can make shortwave receivers, five-tube superheterodyne radios and hi-fi amplifiers." Going over the resume Higuchi, the interviewer, said to Kihara, "You can handle electricity, yet you majored in mechanical engineering. You are a funny person."

Totsuko employees on a recreationnal
trip(Morita and Ibuka in the front row,
first and second from right,

This "funny" man who had come to Totsuko out of curiosity stayed on, destined to work on both the wire and tape recorders.

While still working hard on the wire recorder, Totsuko heard of a machine that could reproduce sound on tape. At that time, Ibuka and Morita frequently visited the Occupation Forces headquartered in the NHK building. One day, a member of the Civil Information and Education (CIE) section showed them this tape recorder. The sound was remarkably better than that of a wire recorder. "This is it.This is what we ought to produce for consumer market. It has great potential. Let's do it with tape," said Ibuka. The wire recorder was thus completely forgotten.

Al and Helen Free and the Development of Diagnostic Test Strips

It is difficult to recall a time when doctors and patients had trouble tracking the presence of glucose and other substances in urine and blood. Lack of sufficient measurement tools made it difficult to manage a host of diseases, including diabetes as well as other metabolic diseases and kidney and liver conditions. Today, self-management of these diseases is an easier process because of the development of diagnostic test strips by Alfred and Helen Free and their research team at Miles Laboratories.


Origins: Early Diagnostic Test Strips

In 1938 Dr. Walter Ames Compton joined Miles Laboratories in Elkhart, Indiana, a company best known for Alka-Seltzer ® . Miles’s executives wanted the company to discover a “wonder drug,” allowing the firm to move into the lucrative prescription drug business. Compton had other ideas.

From his experience as an intern at Billings Hospital in Chicago, Compton appreciated the inadequacy of existing tests for probing the chemical makeup of a patient’s urine. Benedict’s reagent was the primary test for the presence of glucose in urine, an indication of diabetes. Urine was mixed with the reagent in a test tube, then heated over a Bunsen burner. A change in the color of the solution from blue to yellow, orange, or red indicated the presence of sugar. The extent of the color change allowed for an estimate of the amount of sugar in the urine.

The procedure was not very accurate, and Compton, as head of research and development, pushed for the development of a more convenient and precise test. Building on Miles’ experience with Alka-Seltzer, Compton and a colleague, Jonas Kamlet, searched for a method to put reagents in an effervescent tablet that could determine the presence and amount of sugar when placed in a test tube of urine. The scientists succeeded, and in 1941 Miles introduced the effervescent tablet Clinitest ® .

Clinitest contained cupric sulfate, sodium hydroxide, and citric acid mixed with a bit of carbonate to make it fizz. The presence of glucose in urine could be measured by adding a few drops of urine to a Clintest tablet in a test tube and charting differences in color. Clinitest more accurately measured the amount of glucose present than previous tests, making it an early and effective diagnostic tool, and it could be performed and read in a doctor’s office or hospital.

Clinistix ® : The First Dip & Read Test

In 1946 Alfred Free joined the Ames Division of Miles Laboratories to set up a biochemistry division. Free had a Ph.D. in biochemistry from Western Reserve University and additional research experience at the Cleveland Clinic. He assembled a research team, and a young woman working as a quality control chemist at Miles interviewed for a position. Free hired Helen Murray, and in 1947 they married, starting a long personal and professional relationship.

Free’s team improved Clinitest by making it more sensitive, then turned to a second key test for diabetes, using nitroprusside to detect ketones. This resulted in Acetest ® . After several more innovations, Free wondered if there were a better way to do the test. Helen Free remembers: “It was Al who said, ‘You know, we ought to be able to make this easier and even more convenient than tablets, so no one would have to wash out test tubes and mess around with droppers.’”

Free assumed that analytes in urine could be detected on a strip of paper containing reagents that produced color changes. Free’s team also knew that Clinitest detected the presence of any sugar, not just glucose. That diminished the utility of Clinitest for doctors who needed to measure specifically the presence of glucose in urine. The second challenge for the Free team was to embed the reagents on a filter paper strip. The result was dip-and-read Clinistix ® , the first test specific for glucose, released in 1956. The researchers used a double sequential enzymatic reaction: glucose oxidase and peroxidase. The process was very labor intensive. Researchers cut the filter paper, dipped it into reagent solutions, and dried the paper in ovens.

He [Al Free] said, ‘Well, instead of doing it that way, we could get rid of the dropper, if we just dipped the paper into the urine.’ That’s what started it.”

—Helen Murray Free, interview by James J. Bohning in Elkhart, Indiana, 14 December 1998 (Philadelphia: Chemical Heritage Foundation, Oral History Transcript #0176)

Multiple Tests

In 1957 Miles introduced Albustix ® , a dip-and-read test for protein in urine. The company now had diagnostic procedures for the two most common urine tests. Other tests followed. The development of additional diagnostic tests led to another breakthrough: combining reagents for two or more tests on one strip as a further convenience for the user.

Combining two reagents on one strip required creating a water-impervious barrier between the reagents on the paper to prevent the reagents from running together and compromising results. Uristix ® , released in 1957, combined tests for glucose and protein. In the 20 years that followed, Miles developed and manufactured reagents to measure ketones, blood, bilirubin, urobilinogen, protein, nitrite, urinary leukocytes, and pH. The Frees became recognized experts in the field of urinalysis and published several texts and monographs.

Instrument-Based Fingertip Blood Testing

Urine testing does not provide a real-time picture of blood glucose levels since glucose levels in urine lag behind those in blood. In 1964, Miles released Dextrostix ® , reagent strips for testing blood glucose. Five years later Miles introduced the Ames Reflectance Meter ® (ARM), invented by Anton Clemens. Bulky and heavy by modern standards, and powered by a lead-acid battery, the analog device was the first portable blood glucose meter.

Although marketed for use by professionals, the ARM proved effective for patient self-testing. Later improvements by numerous companies included optically read test strips, electrochemical strips, the ability to test capillary blood from anatomical sites other than the fingertips, and continuous blood glucose monitors. Today, self-management of blood glucose is common clinical practice in the management of diabetes.

In the end, Miles Laboratories never discovered its “wonder” drug, but, as Helen Free says, “they sure went hog wild on diagnostics, and that’s all Al’s fault. He was the one who pushed diagnostics.”

Helen M. Free Biography

Helen Mae Murray was born in 1923 in Pittsburgh, the daughter of James Murray, a coal company salesman, and Daisy Piper Murray, who died in an influenza epidemic when Helen was six. The family moved to Youngstown, Ohio, when Helen was three. One of her earliest recollections is accompanying her father, “a real wonderful guy,” on his rounds as he sold coal to dealers who in turn sold to homes.

Helen attended Youngstown public schools through the sixth grade, moving to the suburb of Poland for the seventh grade, where she finished elementary school and high school and where she received straight “A’s.” So did another female student, but because her father could afford to send her to college, the school arbitrarily designated the other student valedictorian and Helen salutatorian. “I didn’t think it was very fair,” she remembers, “but what could I do about it?”

Free had exposure to chemistry and physics in high school, but she intended to be a Latin and English teacher when she entered the College of Wooster in September 1941. That changed after Pearl Harbor, when the housemother announced that with all the men gone to war, the “girls” should take science. She turned to Free and said, “Helen, you’re taking chemistry, aren’t you? Why don’t you switch [majors]?” Reflecting on her decision to agree with the housemother, Free observes, “Just like that! I think that was the most terrific thing that ever happened because I certainly wouldn’t have done the things I’ve done in my lifetime.”

Free took the requisite chemistry courses, and upon graduation landed an interview at Miles Laboratories. She went to Elkhart for the interview and remembers being crammed in a car with three or four men who were going to lunch at the Friday Club, which did not admit women, so they dropped her off at the YWCA. Though she did not get lunch, she was offered a job in the control laboratory testing ingredients for vitamins.

After a few years in the control laboratory, Helen joined her future husband’s research team, a move that satisfied her wish to do research. Al and Helen, who married in 1947, became lifelong research partners as well.

Research at first turned out to be less than Helen Free had anticipated. It was, she remembers, “just as routine as quality control… I did bilirubins all day long, day in and day out.” On the other hand, Free found it “kind of neat”, because the work aimed to discover a new antibiotic. Unfortunately, the effort failed.

Helen Free retired in 1982 but continued as a consultant with what is now Bayer HealthCare LLC through 2007. She has remained active as a champion of science education and outreach. Free chaired the National Chemistry Week task force of the American Chemical Society for five years, and in 1993 she was elected president of the Society, using her post to raise public awareness of the contributions of chemistry to modern life. The ACS created an award in her honor, the Helen M. Free Award in Public Outreach. In 2000, Helen and Al Free were inducted into the National Inventors Hall of Fame.

Tax Treatment

Zero-coupon STRIPS are taxed in a somewhat different manner than most bonds. Traditional bond issuers report the interest that was actually paid on their offerings to investors during the year, but STRIPS does not pay actual interest of any kind, depending on the date it was acquired.

Because STRIPS are issued at a discount and mature at par value, the Original Issue Discount (OID) applies. This requires investors to report phantom interest income that is equal to the increase in the value of the bond for that year. OID that is less than a nominal de minimus amount may be ignored until maturity when it would instead be reported as a capital gain.)

For each year the STRIP is held, the cost basis will increase, and a capital gain or loss could be generated if the bond is sold at a price different from the cost basis. If the bond is held until maturity, the entire discount will be classified as interest income. Investors who purchased STRIPS on TIPS must also report any inflationary adjustment amount every year. The phantom interest from STRIPS is reported by the issuer on Form 1099-OID however, this figure cannot always be taken at face value and must be recalculated in many cases, such as when the STRIP was purchased at a premium or discount in the secondary market.   The tax rules for these calculations are outlined in IRS Pub. 550.

Metallic Fibres

The hallmark of all Indian festivities is the golden glitter of the sarees and similarly-adorned dresses worn on such occasions. All that glitters may not be gold and the ‘zari’ (metallic yarn), responsible for this lustrous appearance, may or may not contain any gold. This paper reviews the different types of metallic fibres and their production.

Metallic yarns or threads, in general, have been known for more than 3000 years. Gold and silver were hammered into extremely thin sheets, then cut into ribbons and worked into fabrics. These were the first ‘man made’ fibres, which came thousands of years before nylon or rayon. The Persians made fabulous carpets with gold thread and the Indians, ornamental sarees with it. The metal threads were twisted, doubled or wrapped around some other thread such as cotton.

With the advancement of technology, metal/conductive textiles found extensive functional applications. These materials have high electrical conductivity and radar reflecting property, yet are lightweight and flexible. Various methods have been developed to coat fibers and textile materials by metals.

» sputter coating
» coating metal powder with binders
» electro less coating
» vacuum deposition

Many technical applications demand properties which cannot be obtained by simply processing common textile material into single textile fabric. However, combination of knitted structure, textile and metal yarn of wire make it possible to create innovative products for multipurpose technical application. Thus knitted fabrics are flexible and extensible and metal wire possess properties which are advantageous in technical textile with regard to their permanent antistatic behavior, known conductivity, shielding from electro magnetic field & resistance to cutting.

The term metallic fibre, in its general sense, means simply a fibre that is made from metal. The generic term “metallic” was adopted by the U.S. Federal Trade Commission and is defined as: A manufactured fibre composed of metal, plastic-coated metal, metal-coated plastic, or a core completely covered by metal. Thus, metallic fibres are: fibres produced from metals, which may be alone or in conjunction with other substances.

These metal filaments were made by beating soft metals and alloys, such as gold, silver, copper and bronze, into thin sheets, and then cutting the sheets into narrow ribbon-like filaments. The filaments were used entirely for decorative purposes, providing a glitter and sparkle that could not be achieved by other means.

As textile fibres, these metal filaments had inherent short comings which restricted their use. They were expensive to produce they tended to be inflexible and stiff, and the ribbon-like cross-section provided cutting edges that made for a harsh, rough handle they were troublesome to knit or weave, and they had only a limited resistance to abrasion. Apart from gold, the metals would tend to tarnish, the sparkle being dimmed with the passage of time.

Despite these shortcomings, the metallic ribbon-filament has remained in use for decorative purposes right up to the present day. The development of modern techniques of surface-protection has brought cheaper metals into use aluminium foil, for example, may be anodized and dyed before being slit into filaments which are colourful and corrosion-resistant.

Ribbon-filaments are now manufactured in considerable quantity, e.g. as tinsel, but they remain an essentially decorative material. The filaments are weak and inextensible, and are easily broken during wear they lack the flexibility that is essential in a genuine textile fibre.

Multicomponent Metallic Filaments

In recent years, the ribbon filament of metal has undergone a transformation, which has changed the commercial outlook, for this ancient product. The metal of the filament is now sandwiched between layers of plastic, which protect it from the atmosphere and from other corrosive influences. The multicomponent filaments produced by slitting sandwich materials of this type are stronger and more robust than the filaments cut from metal foil alone. They retain the glitter of the metal during prolonged periods of use, and have a soft, pleasant handle. Coloured pigments may be added to the adhesive used in sticking the plastic films to the metal foil or metallized film.

Metallic fibres of this type are now widely used in the textile industry, and are produced in a range of colours and forms by many manufacturers. They remain, however, essentially decorative materials and their applications are restricted to this type of use.

Metal-foil and metal-coated yarns are characterised by a flat ribbon-shape with knife-slit edges. Metallic fibres of this type are now widely used in the textile industry and are popularly known as “Lurex” yarn (Trade name).

The main constructions of metallic yarns in order of commercial importance are as follows:

i) Mono ply yarns made from polyester film of 12 or 24 um thickness, metallised and coated both sides either with dear or coloured lacquer (Lurex C 50 and C 100) or with heat and chemical resistant resin-lacquer (Lurex-TE and TE 100). Lurex TE 50 and TE 100 are non-tarnishing and have greatly enhanced resistance to scouring and dyeing treatments of suppleness, brilliance, and yield.

ii) Laminated yarns based on one layer of aluminium foil sandwiched between two layers of 12 um thick polyester film using clear or coloured adhesives (Lurex MF 150). This yarn has higher strength and abrasion resistance.

iii) Mono ply yarns made from 12 um polyester film (transparent - Lurex N 50) or treated with a surface dispersion to give a rainbow effect (Lurex N 50 Irise).

iv) Lurex yarn types C 50, N 50 (Transparent and Irise), and TE 50 can also be obtained supported with two ends of either 17 dtex or 33 dtex monofil nylon. Metallic yarns are usually described in terms of the nominal thickness of the composite film(s) and not the overall thickness of the yarns the thickness of the resin-lacquer coating or adhesive layer is ignored.

The modern and cheap metallic yarn consist of filaments of aluminium covered with plastics: two kinds of plastics are mainly used for the covering. The first and most common is cellulose acetate-butyrate and the second and better is Mylar, DuPont’s polyester film which is chemically similar to Dacron and Terylene. The mixed ester of cellulose with acetic and butyric acids is used more popularly than cellulose acetate, mainly because it has a lower melting point and is more easily worked.

Lurex MM is different from other varieties of Lurex which consist of a sandwich of aluminium between two films of cellulose acetate-butyrate or Mylar. Lurex MM has a basis of metallised Mylar produced by the vacuum deposition of aluminium on Mylar film. A layer of metallised Mylar is either, (a) bonded to one layer of clear Mylar or (b) sandwiched and bonded to two layers of clear Mylar.

Colour is introduced with the adhesive. The important difference is that the metallic layer in Lurex MM consists of discrete particles and not a continuous ribbon. This construction gives Lurex MM particular softness and thinness, and it affects some other properties, too.

The ribbon-like shape of metallic yarns makes width an important factor and all Lurex designations bear a width reference. The amount of yarn cover and metallic lustre of a fabric depends upon the width. Lurex is slit to seven standard widths: 1/128, 1/100, 1/80, 1/64, 1/50, 1/32 and 1/16 inch. The 1/64 inch width is established as standard for weaving and knitting yarn. The various types and widths of metallic yarns are not designated by any standard textile yarn numbering system. Yields are in yards per pound.

Metallic yarns are described by width and by gauge. The gauge is the thickness in one hundred thousandths of an inch of the two layers that form the Lurex sandwich. The gauge figure does not indicate total yarn thickness because it does not take into account the adhesive, pigment or the aluminium layer. For e.g., 260 Butyrate Lurex consists of two layers of 0.00130 inch cellulose acetate-butyrate with a 000045 inch aluminium foil and adhesives between its total thickness is 0.003 2 inch, indicating that the two layers of adhesives must each be about 0.0008 inch. A 260 gauge 1/64 inch yarn yields about 10,500 yards per lb. corresponding roughly to about 430 denier, 1 gauge = 0.00001 inch.

When additional strength and/or special effects are desired, Lurex is available in combined form. Most combining yarns are continuous filament yarns: silk, nylon, fortisan, cotton and rayon are commonly used. Combining is usually done on a hollow spindle twister and is carried out in such a way that the metallic yarn remains flat and the supporting yarn wraps around it. The number of turns per inch in the support yarn can vary but usually number 6.
a) All properties are based on 1/64 inch width yarn gold and silver only.
b) Reflectance results are reported from photo volt reflectometer with green filter against an ASTM standard measuring 89.9%.
c) Some ‘whitening’ can occur on Lurex at boil. This is due to a mechanical pick up of water by the bonding adhesive or protective film and may be cleared by drying.
d) Flammability is evaluated on fabrics. Figures reported are typical for Lurex provided that the accompanying fibres and/or finishes do not influence the behavior of Lurex

a) Multi-Functional Textiles
b) Sensing yarn, woven/knitted into garments.
c) Intelligent textile applications.
d) Heatable textiles as the heating element.
e) Conductive seam ribbons for Clean room garments.
f) Stimulation electrodes knitted into garments.
g) Weavable /knittable lead wires.
h) Heatable textiles.
i) EMI Shielding wall-coverings and other textile structures.

Due to its history as a wire drawn product and its abnormally high specific gravity, metal fiber sizes are typically described in terms of their actual diameter in microns as opposed to their linear weight in denier. As an illustration, a single human hair is 70 micron in diameter, and the current working range of bundle drawn stainless steel fibers is from 1- micron diameter to 100-micron diameter. Most textile applications utilize fibers in the range of 8 to 14 microns. As a way of comparison with polyester, a 12-micron metal fiber has the same diameter as a 1.4 denier polyester fibre.

(a) Electrical Conductivity / Electro-Magnetic Shielding

Certainly, the most distinguishing property of metal fibers is its electrical conductivity. When compared on a sq.cm basis, metal fibers can be classified as true conductors. Carbon fibers and anti-static finishes, on the other hand, are electrically classified as Semi-conductors. These differences can be significant in anti-static applications where atmospheric humidity is low and washing durability is an issue. Tests have been run on fabrics with a grid of stainless steel spun yarns where the same anti-static behavior is maintained after more than 200 wash cycles. In Europe it is reported that stainless steel is the only fiber type to consistently exceed EN 1149 after washings.

This high electrical conductivity also leads to good EMI shielding characteristics. Stainless steel fibers have long been utilized as an additive to plastic casings as a way to shield internal components from electromagnetic radiation. As concerns around EMI shielding grow, these conductive plastic applications have expanded a variety of textile applications for metal fibers. Garments, seals, gaskets and wall-coverings are all commercial application areas for shielding fabrics. There is even ongoing research into the possible therapeutic value of such fabrics for various medical treatments.

(B) Heat Resistance and Strength:

Since the early 1990’s a growing market segment for solid metal fibers has developed in the area of industrial, heat-resistant textiles. There exist many industrial environments that operate above the long-term working temperature of fiber glass and aramid fibers. This is especially true in glass forming processes where temperatures can range from 450 to 6000 C. In this particular application, there are other fibers that can withstand these temperatures from decomposition or melting standpoint, but they experience such a significant loss in strength or flexibility, that their resistance to mechanical load dramatically affects the fabric life.

Yet another important attribute to metal fibers is the ability of certain metals to behave in a chemically inert way, regardless of the environment that they are exposed to.

Metallic yarn of the type discussed here is manufactured by American and French firms under different trade names. Some of these are:-

Dow Chemical Co. Lurex
Fairtex Corp. Fairtex
Melton Corp. Melton
Reynolds Metals Co. Re Aluminium
Standard Yarn Mills Lame
Sildorex SA,France Lurex C, Lurex TE.

i) Chemical resistance:
Metallic yarns, although protected at the top and bottom of their flat sides, are vulnerable at their cut sides. However, as the area exposed is small, tarnishing due to atmospheric exposure is negligible. Chemical attack is serious only if the chemical is one that dissolves aluminium. Any of the Lurex yarns, if immersed in caustic soda, loses metal due to the aluminium dissolving in caustic soda through the cut side of the yarn. Lurex MM is unaffected by 2% hydrochloric acid at 99°C for 2 hours whereas Lurex MF loses metal.

ii) Strength:
Strength of the acetate - butyrate Lurex yarn is not very high, but is sufficient to enable it to be used as warp or weft unsupported. The Mylar coated yams are much stronger because of the strength of the polyester film. They can be used for weaving and knitting.

iii) Heat:
The acetate-butyrate-coated metallic yarns can be washed at temperatures as high as 70°C, otherwise delamination occurs at higher temperatures. Mylar coated yarns can be washed at boil and are safe upto 145°C.

The following procedure will identify the three standard types of Lurex yarn:

1. Burn yarn sample - butyrate Lurex yarn has a rancid odour.

2. Immerse in isopropyl alcohol - butyrate Lurex (film portion) will dissolve, Lurex MM and Lurex MF are insoluble.

3. Stretch yarn sample - Lurex MM and Lurex MF exhibit a stretch of 120-150%, butyrate Lurex will stretch about 20-30%. The aluminium in Lurex MF fractures (separates) on stretching, the aluminium in Lurex MM does not fracture on stretching.

Constantly being designed with new and multiple functionality, it is an exciting time to be a part of the metal fibre industry. Metal fibres can most assuredly help to take textiles into areas they have never been before.

Anita Desai is working as a Senior Lecturer at the Sarvajanik College of Engineering & Technology since June 1997. She is a B.Tech and an M.Tech from the Government S.K.S.J.T. Institute, Bangalore. She is currently pursuing her Ph.D. from the Central Silk Technological Research Institute, Central Silk Board, Ministry of Textiles, Government of India, Bangalore.

She has to her credit over 30 research and review publications and presentations at both, the national and international level. Her biographical profile has been included in the premier edition of Marquis Who’s Who in Asia – 2007 . She can be contacted on: [email protected]

1. Handbook of Textile Fibres - Man-made Fibres, J.Gordon Cook, Merrow Pub.Co., 1984.
2. Identification of Textile Materials, Seventh Edition, The Textile ln Manchester, 1985.
3. Man-Made Fibres, R.W.Moncrief, Newnes Butterworths, London, 1975.
4. Encyclopaedia of Textiles, Prentice-Hall Inc.,USA, 1980.
5. Man-Made Textile Encyclopedia, Interscience Publishers Inc., New York, 1959.
6. Knitting International, June 2001, P. 108-113.
7. Coated textiles principles and application , A.K.Sen, P. 192-201.
8. MANTRA Bulletin, October 1999, P. 1-6.
9. MANTRA Bulletin, November 1999, P. 8-11.
10.Chemical fiber International,Volume 40,November 1997, P. 59-61.
11.Sabit Adanur, Wellington Sears, Handbook of Industrial textile,1995. P 462-463.
12. www.lurex.com

Modern metallic fibres of the multi-component type are based largely on aluminium, which provides sparkle, and glitter at fraction of the cost of the early types of decorative fibre based for example, on gold.

The aluminium in these fibres is in the form of a narrow ribbon-filament of either (a) metal foil, or (b) a plastic film which has been vacuum-plated with vaporized aluminium. This is coated with a layer or layers of plastic film. distort

In these composite structures, the metal is protected from corrosive influences of its environment, and from mechanical damage. Multicomponent metallic fibres have achieved great popularity as decorative fibres and are an in facet of the modern textile industry.


Metallic (m.c.) fibres may be made in almost infinite variety by using different metals and plastics in their manufacture. Aluminium is, however, the metal most commonly selected, and it is sandwiched between cellulose acetate butyrate, cellophane (cellulose) or polyester films.

The following are the types of yarn commonly produced:

(1)Acetate Butyrate, Aluminium Foil: A continuous flat monofilament composed of aluminium foil laminated on both reflective surfaces with cellulose acetate butyrate film.

(2) Cellophane Aluminium Foil: A continuous flat monofilament composed of aluminium foil laminated on both reflective surfaces with Cellophane film.

(3)Polyester, Aluminium Foil: A continuous flat monofilament composed of Aluminium foil laminated on both reflective surfaces with polyester film.

(4) Polyester, Aluminum Metallized Polyester: A continuous flat monofilament composed of aluminium metallized polyester laminated on its metallized surface or surfaces with polyester film.

(5) Polyester, Aluminium Metallized, Non-Laminated: A continuous, flat monofilament composed of a single layer of aluminium metallized polyester protected on its metallized surface.

The acetate butyrate types of metallic fibre are best used for applications which are not subjected to wet processing of other than very mild forms. Polyester types will withstand wet treatments or dry-heat operations as commonly used with most man made fibres, but reference should be made to manufacturer’s recommendations regarding time, pH and temperature conditions.


In the U.S., the former Metallic Yarns Institute established minimum quality standards for metallic (m.c.) yarns for textile purposes, and prescribed a standard system of designation and terms of reference for these yarns.

The following definition of a metallic yarn was established by the Institute, and in general it is still in common use:

Metallic Yarn: A continuous flat monofilament produced by a combination of plastic film and metallic component so that the metallic component is protected.

Metallic yarns are designated by a group of three symbols, each separated by a hyphen, setting forth the two dimensions of width, and gauge or thickness, and generic type.

1. Width. The width of the yarn is expressed as the fraction of an inch to which the yarn has been cut, viz., 1/32, 1/64, etc.

2. Gauge (or Thickness). The thickness or gauge of the yarn is expressed as the sum of the thickness of the plastic film and metallic component in hundred-thousand of an inch, as a whole number, viz., 35, 50, 150, 200, etc.

3. Generic Type. The type of the yarn is expressed on the basis of two components of the laminate - the generic name of the plastic film and the metal.

The components are separated by a comma, viz., Polyester, Foil.
Example: A Polyester/Aluminium Foil Yarn, 1/64 inch wide and 150/100,000 inch thick, is expressed in the industry as:

A manufacturer’s trade name or mark may accompany, but where utilized, either alone or in combination, the above must be separately stated or referred to.

The properties of a metallic (m.c.) fibre depend upon the nature of the plastic film used in its production, and of the metal used as the centre of the sandwich.

In general, the fibres behave in a manner similar to man-made fibres spun from polymer on which the plastic film is based. Acetate butyrate metallic filaments, for example, have a resemblance to acetate fibres polyester type metallic filaments are similar to polyester fibres in their general characteristics.

The nature of the aluminium layer inside the sandwich affects the properties of the metallic filament to a significant extent. In Types 1, 2 and 3, the aluminium is a continuous layer of foil in Types 4 and 5, on the other hand, it is in the form of discrete particles which have been deposited on a layer of plastic film. The discontinuous layer of the latter type results in a finer, softer and more pliable filament which differ in many respects from those of the foil-type metallic fibres as indicated below. The figures quoted refer to specific metallic fibres of the various basic types, but there is considerable variation in properties between fibres of the same type.

Fine Structure and Appearance:

Metallic (m.c.) fibres are flat, ribbon-like filaments, commonly 3.2-0.2 mm (1/8-1/128 in) width. They are smooth-surfaced, and may be coloured or uncoloured.

Acetate Butyrate, foil: 2.6 cN/tex (0.3 g/den).
Polyester, foil: 6.2 cN/tex (0.79 g/den).
Polyester, metallized: 11.0 cN/tex (1.25 g/den).

Acetate Butyrate, foil: 30 percent.
Polyester, foil: 140 percent.
Polyester, metallized: 140 percent.

Acetate Butyrate, foil: 75 percent at 5 percent elongation.
Polyester, foil: 50 percent at 5 percent elongation.
Polyester, metallized: 100 percent at 5 percent elongation.

Relative flex resistances of the main types are in the following ratios:
Acetate Butyrate, foil: 1
Polyester, foil: 18
Polyester, metallized: 70

Acetate Butyrate, foil: fair.
Polyester, foil: good.
Polyester, metallized: excellent.

Effect of Moisture Regain:

Acetate Butyrate, foil: 0.1 per cent. Polyester, foil: 0.5 per cent.
Polyester, metallized: 0.25 per cent.

Softening point: Acetate Butyrate, foil: 205°C.
Polyester: 232°C.

Some loss of strength on prolonged exposure.

Generally good resistance.

Acetate Butyrate: good resistance to weak alkalis degraded by strong alkalis.
Polyester: these also show similar characteristics. Metal foil types are more resistant.

Acetate Butyrate: Similar to acetate yarn. Not affected by sea water, chlorinated water, or perspiration. Generally resistant to bleaches, but sensitive to caustic soda used in peroxide bleaching. Also sensitive to copper sulphate and sodium carbonate at high temperatures.
Polyester: Generally good resistance.

Effect of Organic Solvents

Acetate Butyrate: Attacked by acetone, ether, chloroform, methyl alcohol, tetrachloroethane. Not attacked by benzene, carbon tetrachloride, ethyl alcohol, perchloroethylene, trichloro ethylene.
Polyester: Attacked by acetone, benzene, chloroform, tetra chloroethane, trichioroethylene. Not attacked by carbon tetra chloro ethyl alcohol, methyl alcohol, perchloroethylene, white spirit.

Metallic (m.c.) fibres conduct electricity - the metallized types having a lower conductivity than the foil types.


Metallic (m c) yarns are used in the industry almost entirely as decorative materials. They provide a metallic, g1itter and sparkle that cannot be obtained in other ways. The aluminium foil that provides the glitter in a modern metallic yarn is protected from corrosive materials of its environment by the plastic film in which it is enclosed. It remains untarnished through long periods of wear, and polyester types will withstand repeated launderings without losing their sparkle. Metallic yarns are not affected by sea water or by the chlorinated water of swimming pools and are widely used in modern swimwear.

The dyestuffs used in colouring metallic fibres are usually fast to light and the colour remains bright to match the sparkle from the aluminium foil.

As metallic (m.c.) yarns are used primarily for decorative purposes, they do not as a rule contribute significantly to the strength of fabrics or garments. Nevertheless they may be used as weft or warp yarns, and are strong enough to withstand the weaving, and knitting operations. If necessary the metallic yarns are combined with support yarns, such as nylon. The plastic film of the metallic yarn is flexible, and the yarns are extensible to a degree that depends upon the type.

Aluminium will corrode and tarnish in air, and in contact with seawater, but in metallic fibres it is protected so effectively that it retains its glitter for long periods. The chemical resistance of a metallic filament is, in general, the chemical resistance of the plastic film. In the case of polyester films, this is outstanding.
If metallic fibres are held in contact with strong alkaline solutions for prolonged periods, the aluminium may be attacked at the unprotected edges of the ribbon. Metallic fibres should not, therefore, be subjected to alkaline reagents of significant strength.

Organic solvents, too, may attack the laminate adhesive or lacquer coating great care should be taken in dry cleaning to ensure that an appropriate type of solvent is used.

The plastic films in metallic fibres are thermoplastic, and will soften at elevated temperatures. Delamination may occur if the fibres are heated, and acetate types in particular should be processed only at low temperatures.

The plastic film may be permanently embossed by heat and pressure, and special effects may be introduced into the fibres in this way.

Acetate butyrate types may be hand washed in lukewarm water with a mild soap. If processed as silks or woollens, they may be safely washed in home or commercial laundry equipment.

Polyester types may be washed at temperatures up to 70°C. Dimensional stability is good and crease resistance is fair.

Most coated polyester yarns will not withstand treatments other than those used for silks or woollens.

Acetate butyrate types must be dried at as low a temperature as possible. Polyester types may be dried at higher temperatures as used for polyester fibres, with the exception of most coated types.

Acetate types should be ironed at temperatures no higher than 105°C. Polyester types may be ironed at temperatures up to 130°C. Rayon setting is preferable for both types.

Metallic fibres may be dry cleaned without difficulty, provided care is taken in the selection of solvent to suit the type of fibre.

End uses: Metallic (m.c.) yarns are used for decorative purposes in almost every field of textile application. Important end-uses include women’s dress goods, upholstery, curtains, table linens, swimwear, packaging, footwear, car upholstery, suits and hats.


Extrusion And Metal Coating

The incorporation of metal into textiles dates back to the Roman era, when they were mainly used for decorative purposes. The tinsel yarns used to add glitter to fabrics were made by flattening thin wire or sheets of noble metals like gold or silver. By the 1930s, aluminium foil strips coated on both sides by cellulose acetate-butyrate, to prevent them from tarnishing, were used. The yarn could be colored by anodizing. All of these yarns had poor compatibility with the more flexible and extensible textile yarns. After the development of vapor-deposited aluminized polyester in the 1960s, 1 mm wide strips of these films were used as yarns, with much improved flexibility.

The American made yarns can best be described as a ham sandwich. The metal foil, metallised pigment and colouring matter might be considered the meat. The meat is placed between two layers of transparent plastic film. The adhesive used between layers to bind all the layers together into one film might be compared to the butter that holds the bread and meat together.

The raw material is a roll of aluminium foil of 0.00045 inch thickness and 20 inch wide. To both sides of the sheet is applied a thermoplastic adhesive to which has already been added the required colouring matters. The adhesive-coated foil is heated to about 90-95°C, and a sheet of cellulose acetate-butyrate transparent film is laminated to each side of the foil by passing through squeeze rollers at a pressure of 2000 lb/in (Fig. I). The laminated material is then slit into filaments of the required width, the most popular width being 1/64 inch although other sizes from 118 inch to 1/120 inch are also made.

The nature of the adhesive that is used is important and not usually disclosed. Gold is the most important colour which is produced by the addition of an orange-yellow dyestuff to the adhesive. Silver is simply the colour of the aluminium itself. Other colours such as bronze, peacock blue and red are obtained by using the suitable pigment. Multi-coloured efects, e.g. red and green alternating irregularly along the length of the yarn, are obtained by pre-printing the plastic film and laminating in the usual way.

A. Metal coating with a binder:

The process is similar to conventional polymer coating. High leafing aluminium pastes (65-70%) are incorporated into a polymeric carrier, like synthetic rubber, PVC, polyurethanes, silicones, acrylic emulsions, etc., and spread coated on the fabric. The coating method may be conventional knife or roller coating. The adhesion, flex, and chemical resistance of the coated fabric depend on the type of polymer used, but they are not highly reflective.

In this process, the substrate to be coated is placed in a chamber over a set of crucibles containing the metal to be coated in the form of a powder/wire. The chamber containing the whole assembly is evacuated to 0.5-1 torr. The crucible is heated by resistance heating to melt the metal. The temperature of heating is so adjusted that the vapour pressure of the metal exceeds that of the chamber pressure, so that substantial evaporation of the metal takes place. The temperature required for aluminium is about 1200ºC. The roll of web to be coated is passed over a cooled drum placed over the crucibles. The metal atoms coming out of the molten metal hit the surface of the web to be coated and condense in the form of solid metal as it passes over the crucible. The production speed is quite high, ranging from 150-500 m/min. The items to be coated should be pretreated for proper adhesion of the metal. Continuous metal film coatings can be formed on just about any surface, film, fiber or fabric with thickness ranging from micron to millimeter. Several metals can be vacuum evaporated, most common being aluminium, copper, silver, and gold. Difficulty arises in the case of metals, which sublime rather than melt and boil.

The equipment consists of a vacuum chamber containing an inert gas, usually argon, at 10-3 to 10-1 torr. The chamber is equipped with a cathode (target), which is the source of the coating material, and an anode, which acts as a substrate holder. Application of an electrical potential of the order of 1000 VDC, between the two electrodes, produces a glow discharge. A flow of current occurs due to movement of electrons from cathode to anode. The electrons ionize the argon gas. The argon ions are accelerated toward the cathode at a high speed due to high electric potential. The bombardment of the energetic ion on the target results in a transfer of momentum. If the kinetic energy of the striking ion is higher than the binding energy of the surface atoms of the material of the target, atoms are dislodged or sputtered from its surface by a cascade of collisions. Typically, the threshold kinetic energy of the ions should be between 10-30 EV for sputtering from the surface. Some of the ions striking the target surface generate secondary electrons. These secondary electrons produce additional ions, and the discharge is sustained. Considerable heat is generated during the sputtering process, and it is necessary to cool the target. The sputtered atoms and ions condense on the substrate to form a thin film of coating. The relative rates of deposition depend on sputter yield, which is the number of atoms ejected per incident ion. The sputtering yield varies with the target material and increases with the energy of the incident ion. The method is applicable to a wide range of materials and gives more uniform coating with better adhesion than simple vapour deposition. The process is however, more expensive, and the rate of deposition is lower (30 m/min)

It is a process to deposit metal film on a surface, without the use of electrical energy. Unlike electroplating where externally supplied electrons act as reducing agent, in electrodes plating, metallic coatings are formed as a result of chemical reaction between a reducing agent and metal ions present in solution. In order to localize the metal deposition on a particular surface, rather than in the bulk of the solution, it is necessary that the surface should act as a catalyst. The activation energy of the catalytic route is lower than the homogeneous reaction in solution. If the deposited metal acts as a catalyst, autocatalysis occurs, and a smooth deposition is obtained. Such an autocatalytic process is the basis of electroless coatings. Compared to electroplating, electroless coating has the following advantages:

(l) Nonconducting materials can be metallized

(3) The process is simple and does not require electrical energy

Electroless coating is, however, more expensive.

For successful deposition of coatings, only autocatalytic reduction reactions can be used. As such, the numbers of metals that can be coated are not many. Some of the common reducing agents are sodium hypophosphite, formaldehyde, hydrazine, and organo boron compounds. Each combination of metal and reducing agent requires a specific pH range and bath formulation. The coating thickness varies between 0.01 um to 1 mm.
A typical plating solution consists of
a. Metal salt

c. Complexing agents, required in alkaline pH and also to enhance the autocatalytic process

e. Stabilizers, which retard the reaction in the bulk and promote autocatalytic process.

Some important metal coatings are discussed below:

a. Copper:
The most suitable reducing agent is formaldehyde. The autocatalytic reaction proceeds in alkaline pH (11-14). The commonly used complexing agents are EDTA, tartarate, etc.

b. Nickel:
Sodium hypophosphite is the most popular reducing agent for nickel. The autocatalytic reaction occurs in both acidic and alkaline pH. Sodium citrate is used as buffer and complexing agent. The coating obtained by sodium phosphite also contains phosphorus (2-15%).

c. Silver:
The plating solution consists of ammoniacal silver nitrate with formaldehyde, hydrazine, and glucose as reducing agents. Because the autocatalytic activity of silver is low, thick deposits cannot be obtained. Electroless plating of textiles is being adapted for different functional applications.

The slitting operation involves the two main types of cutting by which a metallised polyester film is converted into the tape filaments:
(a) Rough Slitter
(b) Micro Slitter

The metallized polyester film supplied to the slitting operation has the following parameters:

(1) Thickness: Normally ranges between 12 to 25 Microns.
(2) Length: Sheet in the form of roll having the length from 5000 to 10,000 meters.
(3) Width: The width of the sheet ranges between 510mm to 1000mm.

his slitter cuts the large polyester sheet into Pancakes. The width of the each Pancake is 54mm. In addition side strips of 2mm are kept extra on each side. Thus the resultant width of the pancake is 58mm.
Cutters of different size are used for this operation, for example 0.2mm, 0.23mm, 0.25mm, 0.30mm, 0.376mm, etc. Pancakes are also in the form of rolls supplied to the Micro Slitter.

The Micro Slitter is a general name given to both slitter and winder for producing the yarn 0.15mm -1 mm wide.

In this operation Pancakes are converted into numbers of tape filaments. It has two main parts,
(a)Cutting Mechanism
(b) Winding Mechanism

Cutting of Pancakes and Winding of tape filaments are carried out simultaneously.

The cutting mechanism consists of two parallel shafts. On each shaft blades are mounted side by side such that the edge of one blade on one shaft slightly touches the edge of the blade mounted on the other shaft. The cutter is mounted on to the shaft with the help of Separator and Support Ring. The width of the tape filament decides the width of the cutter.

The winding mechanism consists of number of winding positions. The winder is driven by a separate motor. The traverse mechanism is also provided for obtaining the parallel wound package. The speed of the winder is 2.5% to 5% higher than that of the cutter.

Nowadays machines can produce a high quality of covering yarns for even 200, 300, denier of polyester yarn, cotton and even silk, which is applied to stocking, socks and particularly woven elastic fabrics.

The important characters of the machine are the balance and the alignment of spindles and guide rollers. It is well designed for flexibility and anti-wearing by using good quality of materials to each part of character. The specification of machine can be changed according to a pitch and number of spindles.

Metallized products are used in industrial, specialty and protective clothing applications. There are various ways to combine metals with textile materials for specific applications.
Metallized fabrics provide good abrasion resistance, reflectivity over extended time, wear resistance and molten metal splash resistance.

Textile fabrics are used as substrates in metallized protective materials. Woven, knit and nonwoven fabrics may be coated or laminated with metal surfaces. Substrate fabrics can be made of aramids, carbon based fibers, PBI, glass, cotton, rayon and others. Aluminum is widely used in metallized fabrics.

In aluminized fabric, aluminum molecules are deposited on a PET film. Examples are Mylar from DuPont and Hostaphana from Hoechst. The aluminized film can reflect up to 90% of radiant heat. Gold can be used for reflection of up to 100%, but it is expensive.

Laminated metallized fabrics can be made of several layers of materials. A typical five-ply dual mirror
aluminized fabric has the following layers: aluminum, protective film, a second layer of aluminum, heat stable adhesive and fabric.

Metal sliver can be blended with synthetic or natural fibers to produce conductive textiles. Stainless steel sliver used for this purpose usually has 4.8 or 12 micron fiber diameters and weighs approximately 1.2 or 4 grams. The fiber length may vary from 1.5 to 6 inches. There are several methods to produce metal fibers including bundle drawing (most common), wire drawing, shaving, shearing, melt spinning, melt extracting and stretch casting. For maximum conductivity, the steel fiber is introduced at the last drawing operation. Protective fabrics made from metal-based blended fibres are suitable to protect individuals from the hazardous effects of electrostatic discharge and electromagnetic radiation.

Multi-filament metal fibre yarns can be twisted or wrapped with textile yarns to produce composite yarns. These yarns are suitable for cut resistant apparel items, antistatic brushes for business machines, lightning strike protection and antistatic filter bags. The most widely used metal yarns are 12 microns/91 filaments, 25 microns/91 filaments.

Nonwoven Metal Based Fabrics

Chopped metal fibres can be air or wet laid with textile fibers to form nonwoven textiles. For air layering, 1 inch fiber length and 4-38 micron fiber diameters are used. For wet layering, fiber lengths of 0.125 to 0.5 inch have been successfully used. Binders or sintering may be used for stabilization. During sintering, the organic binder fibers are burned off, leaving a 100% metallic fiber structure. In general, fiber diameters of 4-15 microns in 0.125-0.250 inch lengths are suitable for this process
Test methods and characteristics to evaluate the metallized products include the following:

• Military Specification, MIL-C-87076A, for Aluminized, Twill Weave, Aramid, Coated Cloth
• MIL-C-24924A Class I (fire proximity garments)

Applications in technical textiles:

Following Attributes of fibres make them suitable for applications in technical textiles:
• Electrical Conductivity
• Electro Magnetic Shielding
• Anti-Microbial
• Heat Resistance
• Strength
•Chemical Reactivity
• Corrosion Resistance
• Flexibility (compared to wire or steel wool textile structures)
• Weldability

Existing and Potential Applications:

Given the above product characteristics, some existing and potential applications are as follows:

1 Anti-static protective clothing garments in the Petro-chemical, pilot suits, fire workers suits, etc.
a. Anti-static fabric panels for garments
b. ESD shoe soles and Overshoes
c. Sewing threads for connection of fabric panels for improved sleeve-to-sleeve
ESD compliance.
2. Shielding fabrics for utility workers in high field areas.
3. Muscle stimulation electrodes.
4. ESD Brushes.
5. Bulk container bags for powders and pellets.

Metallised Films by Camvac

Metallised Films are generally polymer films which have been coated with a thin layer of aluminium during the production process to increase a products shelf-life, appeal or add certain barrier properties.

Camvac’s original founders invented the process of Vacuum Metallisation in the 1930’s. Since then, Camvac has grown into one of the leading manufacturers and suppliers of metallised films and non-woven materials to a varying array of customers. A large proportion of our products are patented, and the processes are licenced, resulting in truly unique products to Camvac. In our manufacturing facility we have three 2200mm wide metallisation machines and one 1650mm wide metallisation machine.

Metallised films are created to reduce the permeability of the film to light, water and oxygen whilst creating a highly reflective, mirror-like finish. During the metallising process, the properties of the film are unaffected. Comparing to aluminium foil, metallised film is a more robust product, possesses the ability to be heat sealed and is lower density. All whilst being available at a much lower cost. The characteristics of metallised PET film makes the material an exceptional packaging film for a vast array of food items. Applications include snack foods, coffee and microwave meals.

An ever-increasing wealth of film metallising expertise in high metal adhesion, high barrier, decorative, low optical density, strip and clear barrier means that Camvac is well placed to continue as a leading solution provider in each of its chosen markets.

Some products which are produced using the metallising process are Camcrisp, Camlite and Camtherm.

Camcrisp is a controlled optical density metallised film for microwave susceptors. Recent consumer changes have seen the ‘food on the go’ market grow massively, becoming the hallmark of modern living and with it the need for microwavable packaging which can both protect the product and allow fast preparation.

Camcrisp is a metallised film specifically developed for the microwave snack market. The metallised film is used to enable ‘browning and crisping’ of products such as pizzas, garlic bread, potato chips and popcorn during the re-heating process. Precise control of the film optical density gives assured microwave performance and controlled heat generation.

Metallised films are not only used within the packaging of foods and liquids. The films also possess certain properties making them ideal for protecting electronics which are sensitive to light and for using within the manufacture of insulation.

Camlite is a controlled optical density metallised film. Originally developed for packaging light sensitive electronic components. Camlite is an example of a multipurpose product with at least two applications. Whilst giving the functional advantage of controlled light transmission, Camlite is a metallised film which has anti-static properties and gives a stylish aesthetic quality to promotional packaging application in the form of tinted transparent envelopes e.g. for sales literature and magazines.

Camtherm is metallised films and laminates for thermal insulation. Camtherm can be supplied as a laminate or single web structure and has been designed for a range of insulation applications. It can be produced in a variety of material substrates. All of which demonstrate exceptional barrier to oxygen and moisture as well as excellent emissivity values.

Applications for Camtherm are typically industrial and engineering insulation products vacuum insulation panels, gypsum-type duplex board and moisture barrier underlay for flooring insulation.

Camvac’s metallised films have a wide range of uses and are constantly increasing. Recent developments and a growing consumer demand have resulted in metallised films being available in a range of environmentally friendly solutions under our Camvert brand.

So, whether you are looking to increase the shelf appeal of your product or need a metal finish to your end-product, metallised films are a proven way to achieve your product differentiation and stay ahead of the competition. Camvac’s metallised films are used in a wide range of products from home compostable acetate film within the luxury packaging marketplace to thermally efficient components of windows and double glazing.

Camvac’s long trading history and experience means we are well positioned to be able to use this knowledge and expertise to apply metallising to a wide range of end uses and industries.

To discover more about Camvac’s film metallising capabilities contact us today.

Industrial Manufacturing, Converting & Tape Distribution

MBK Tape Solutions is a recognized leader in converting of industrial adhesive tapes, foams, films, fabrics, non-woven materials and other related products used in the production, assembly, fabrication, and extrusion of finished goods. With access to material suppliers both domestically and internationally, the MBK team of specialists will help you find the most cost-effective material for your application and then convert it to your requirements.

Our converting and fabricating services include rotary and flatbed die cutting, tabbing, precision slitting, multi-layer laminating, printing, rewinding and much more. Being a job shop, we are adaptable and flexible to meet your ever-changing needs. Distributors and adhesive tape converters utilize MBK custom adhesive converting services for short and long runs when minimums cannot be met from adhesive tape and related specialty tape manufacturers. Throughout the industry, MBK is known as “The Converters Converter.”

Below are Industrial Tapes and common materials used in the Manufacturing and Converting Market .

Metallised Strips - History

Part One, 1940 - 1965

1960's And Later Equipment


GE's entry into the market of the 1960's was the Transistorized Progress Line, or TPL equipment, although production of the Progress Line continued simultaneously for a few years. All manufacturers were in a race to produce equipment which was as transistorized as possible, and at that time this meant using germanium transistors. Because of this race, some less-than-optimum implementations or processes were sometimes rushed into production. GE's TPL consisted of a fully transistorized receiver and a partially transistorized transmitter, in a modular housing which could be taken apart and mounted throughout a vehicle in separate pieces. The TPL was initially supplied as a rather large under-dash package consisting of a front section containing the receiver and part of the transmitter exciter, a center section containing the balance of the transmitter exciter and a power amplifier, and a rear section containing the power supply for the transmitter, as shown in the first photo below. A complicated engine-compartment mounted fuse-block relay unit switched power to the power supply section and muted the receiver, something done internally in Motorola and competitive equipment.

TPL shipments began in approximately late 1959. For some reason, most TPL's seem to have been made in 1961-62, at least in my observation of used equipment. The TPL was officially first announced at the Forestry Conservation Communications Association meeting in Hot Springs, Arkansas in July, 1959.

There was an optional cable and bracket kit which allowed the dash mounted receiver to be separated from the rest of the unit in an ugly, impractical and unreliable arrangement which then resulted in the creation of a trunk mounted mobile with an oversized control head. This led to the somewhat incorrect perception in the industry that the TPL had "the receiver contained in the control head." A third arrangement which seems to have been developed a year or two after introduction, finally placed all sections of the TPL into a trunk mounted package and supplied a conventional, quite small control head with just volume and squelch controls inside it. In all versions, the open ventilation of the transmitter exciter and power amplifier section subjected them to dirt and moisture intrusion to a greater extent than enclosed radios. As a matter of trivia, there were some issues with poor contact to the pins of the Cinch-Jones style main control connector on the front of the trunk-mounted style TPL, resulting in a re-designed cable connector retainer clip assembly and probably resulting in the replacement "MASTR Professional" series using a round-pin connector of proprietary GE design.

TPL equipment was only made in VHF low and high band models. There was no UHF TPL. The UHF counterpart to the TPL was the Accent 450, although the Accent was introduced in the early 1960's. TPL offered many unusual options, such as dual front ends and noise blankers, most of which were added underneath the equipment in ugly accessory housings, connected by unique and proprietary connectors. The high band TPL was introduced first, in 1959, while the low band versions were introduced in June, 1960.

The speaker in the TPL series contains the radio's sole audio amplifier as well. This was a theme of the early 1960's also used other manufacturers such as RCA in its first hybrid equipment (Super Carfone series.) There were two speakers available, a 2 Watt and a 10 watt model. The 10 Watt speaker was supplied with a coiled cord and the unique feature of a lip on the rear edge to allow it to be removed from its bracket and placed on a vehicle window so that it could be heard by workers away from the vehicle. This feature was generally not seen again on later GE equipment although Motorola thought enough of it to copy the lip on the housing of their Micor line of speakers in 1970.

The TPL used a number of proprietary items such as the connectors for the microphone, relay assembly and speaker, which were never seen again on any other GE equipment. There were two styles of microphone connector for the Shure made microphone - - a disposable rubber-style one molded with the cord, and a re-usable metal bodied version. The housings were made from a surprising number of elaborate die castings, in shapes quite unusual compared to other equipment in the industry.

Also surprising was the use of sockets for the transistors, something not seen on competitive equipment, and one of the downfalls of the TPL. In rough service, it was reported that it was not unusual for technicians to pull a defective unit for repair only to find several of the transistors rolling about loose in the bottom of the receiver housing! Apparently the reliability of the transistor was not anticipated, and the designers chose to treat them like vacuum tubes, making them plug into sockets, but without any retaining hardware.

The high band receiver in the TPL was produced in two models. The original receiver used a coil and capacitor L-C tuned circuit "front end," while the last-generation TPL used a helical resonator front end. The exciters also went through two models. The early exciters contained a sealed delay-line modulator module, while the later ones were improved with a more conventional design. Either TPL transmitter modulator has excellent audio. A 10 Watt TPL mobile could be made into an 80 Watt model by plugging an 80 Watt power supply and transmitter module onto the receiver/control/exciter section.

The TPL was plagued with numerous problems which have generally relegated it to the category of one of the largest design failures in the history of two way radio, although some of this criticism was in retrospect unfair. The plug-in transistors fell out of their sockets, as mentioned, and in my experience the solder joints of the stiff wires connecting the two opposing circuit boards in the receiver section could develop cracks. The early models were somewhat sensitive to vehicle battery voltage variations causing the squelch threshold to vary. The complicated cabling was an installation nuisance of major proportions.

On the other hand, the TPL had a number of unique performance advantages. When squelched in stand-by, it drew less current than a single pilot lamp, about 50 ma., allowing it to be left on at least overnight in a vehicle, if not permanently, depending upon the level of radio traffic and the setting of the volume control. Even today's equipment can not make that claim. Unlike the standard Progress Line, the TPL control head featured a stand-by switch which switched off the transmitter's tube filaments to save current, as well as the green "on" pilot lamp.

Ray Minichiello, who retired as GE's Manager of Product Planning, Communications Products Department, was with the company at the time the TPL was in production, and shares the rare inside story that the TPL's initial problems were not the fault of its electrical design. It seems that the transistors used in the TPL were primarily supplied by GE's Transistor Department in Syracuse, New York. In Ray's own words:

When high rates of transistor failures in the field were reported to the Transistor Department, it was but a puzzle as other customers of the same type transistors enjoyed 100% reliability. The relationship between the two departments soured to include threats of switching to Motorola products! The Syracuse gang requested a hands-on following of each operation on receipt of the transistors, inspection and preparing, including the process of installation in the board.

The Syracuse engineers discovered that after receipt of the transistors at Lynchburg Receiving Section, the transistors were inserted in a device to cut the leads to the proper length. However, it was discovered that the device pulled the leads during the cut, only to fracture the internal junction! When the transistors were inserted in the finished product, it was only a matter of time that the junction dislodged, resulting in failure of the TPL. The Methods man quickly modified the design of the lead cutting tool and thereafter TPL's enjoyed a high reliability reputation. However, it was regretfully long after the first shipments of the TPL to the field and the product was already subject to a bad "rap."

Accessory decks were added to the TPL between the receiver section and the exciter, such as the Channel Guard board. Yet additional decks were added underneath, such as the noise blanker and the dual front end sections, making a rather bulky package. Note that the front (receiver) section is connected to the rest of the chassis solely by two coaxial cables with RCA connectors, the DC voltage being superimposed onto the cabling.

The majority of TPL's seem to have been made in VHF high band models, and they were purchased in large numbers by the US Government and the Bell System. TPL production ended in approximately 1965, representing one of GE's shortest-lived mobile radios. If nothing else, it was certainly an unusual and attractive set in the dash mount configuration.

At a sales meeting in 1962, GE announced the "Ruggedized TPL." I have no idea what this consisted of, other than possibly the new helical resonator receiver front end deck and a re-designed rear-mount connector fastening system.

Shown below is a rear mount version of the TPL, in a 35 Watt configuration:

Unusual 4 Frequency TPL rear mount control head:


During the development of the TPL line, a transistorized mobile PA amplifier was developed. This too used socketed small signal transistors, while the main amplifier DS501 style transistors were hard wired into the circuit. These amplifiers were initially available as the model series 4EA5, which was apparently intended mainly as an accessory to the Progress Line and is specified as a 20 Watt unit. Later models were the 4EA12, as shown here, which seems identical to the 4EA5 other than having a TPL series microphone socket as an option and shows a 25 Watt output. 25 Watts was not very much power for a siren, and it seems as if few of these were sold. I recently acquired the example below, which is the first one I have seen in 50 years of collecting. The original model 4EA5 was originally only a PA amplifier, the faceplate did not have the center switch. There was a field modification kit for adding the siren feature, which among other things involved replacing the faceplate and adding an additional circuit board. The 4EA12A10 was the PA-only model while the 4EA12B10 was the model shown below, with the the siren.

Pacer and Accent 450 are grouped together as they were both economy radios built for a short period of time. The desktop base station versions of them appear similar.

PACER (1961-1965)

Pacer was a VHF economy all-tube under-dash radio which used printed circuit boards with tube sockets mounted on them, introduced in January, 1961. It was an approximately 15 Watt unit finished in Progress Line blue paint, with TPL style red plastic knobs. They were purchased primarily by towing companies, taxi operators and small businesses which typically had just one or two mobiles, such as plumbing and electrical contractors. Although not that bad a design, the Pacer gained the reputation as an unreliable and poor performing radio, primarily because of the issue of hot tubes cracking the traces of the printed circuit boards. Nonetheless, many saw long years of service. There was no "standby" feature on the Pacer and the transistor power supply drew current at all times during operation, as well as being acoustically noisy, as was the crystal oven thermostat which made a "plink-plonk" sound at regular intervals. This was probably not an issue in a vehicle such as a tow truck, where the engine would be running at all times and rather noisy itself. There were no UHF Pacers, the equipment was made in low and high bands only, as well as in an attractive tabletop base station of totally different appearance. Few Pacers have survived.

Photo courtesy Ben Kittredge WA1PBR

Accent 450 (1961-1964)

The Accent 450 was a strange and unique UHF radio using tubes mounted on printed circuit boards as on the Pacer, with thick anodized aluminum heat sink-shields for the transmitting tubes attached to the sidewalls of the case. It was all vacuum tube type other than the transistors in the power supply. The receiver front end made use of a 1N21 UHF cartridge mixer diode. Sensitivity was relatively poor, but comparable to competitive equipment. The Pacer transmitter made use of a new, expensive and rather unreliable (in my opinion) Amperex glass UHF tube, type 7377. These tubes were short lived in actual use and it was unusual to find an Accent 450 in service which would produce more than a few Watts, if that. The odd control head of the Accent contained the speaker and could be mounted either on the front of the radio itself or remotely, using an extension cable. Not many Accents were made and they seem to be regarded as an even worse failure than the TPL. The Accent 450 had no provision for a locking tray or case, and the lid was a flimsy steel plate. The Accent 450, as its name suggests, was made only in a UHF version. Few Accent 450's have survived. Local examples have been refugees from the Port of Oakland, California.

Shown below is an example of an Accent 450 configured for front-mount operation, in the museum room at the Harris (GE) facility in Lynchburg. Photo courtesy Mark Cobbeldick


The Voice Commander was GE's first hand-held VHF FM two way radio, introduced in July, 1961 and replaced the Progress Line pack set (which in late versions contained sections identical to the TPL mobile receiver.) The Voice Commanders II and III were fully solid state with Germanium transistors, while the Voice Commander I used subminiature wire-lead tubes for the transmitter power amplifier. The fully solid state Voice Commander, the II series, was in production by September, 1962. Coming from the same design-era as the TPL, Accent 450 and Pacer, the Voice Commanders were also considered failures for many reasons. The Voice Commander was a strange all plastic blend of the properties of a pack set mated to that of a hand-held radio with perhaps the worst features of both! Introduced in July, 1961.

The push-to-talk button on the Voice Commander is in the front center of the unit, requiring both hands to hold the radio up and talk into it. There was also a remote microphone which plugged into a peculiar proprietary 3-pin connector on the left side of the carrying handle, on the III Series. The II and I series did not offer this option. The telescopic antenna could easily contact the grounded carrying handle, blowing the output transistors in the transmitter if the radio were on the air at the time. The large battery pack of the solid state Voice Commanders contained many sub-C nickel cadmium cells in a series-parallel arrangement. Although provided with a two channel switch, nearly all Voice Commanders were single channel, and most seem to have been wide band. The Voice Commander receiver was assembled from several modules encased in brass sheeting, while the transmitter was a single circuit board. Power output was roughly one watt.

The battery box was available as a rechargeable nickel-cadmium style (II and III) or a dry battery version, as shown below (I, II and III.)

The receiver of the Voice Commander was somewhat subject to overload and assorted severe cross-modulation and intermodulation-distortion issues in high signal strength areas.

There were no UHF Voice Commanders, and it is believed that few low band versions were built. The Voice Commander was built from approximately 1960-65. Considering that Motorola's successful HT-200 "Handie-Talkie" was introduced in 1963, it is easy to see why the Voice Commander was utterly non-competitive, although it was available as a transistorized portable before the Motorola HT-200 was available.

In hindsight it is easy to think that had GE assembled the Voice Commander into a small "lunchbox" style pack-set case similar to the Motorola PT300 sets, with a conventional separate microphone and standard antenna, it probably would have been very popular.

It is hard not to think that the years 1961-63 must have been bleak ones for GE, in that virtually all of their new product lines during this period, in my opinion, were rather peculiar looking if not ugly, and often unreliable.

The Pocket Mate was GE's first actual hand-held radio and designed to compete with Motorola's HT-200 which had been introduced in early 1963. The Pocket Mate is believed to have been introduced about 1965 and is much smaller than competitor Motorola HT-200. The Pocket Mate is almost as bizarre in appearance as the Voice Commander or the Accent 450 radios. A peculiar captive telescopic whip antenna was permanently attached, and flipped upwards on the side of the radio to a vertical orientation. The round speaker in the front center also acted as the microphone, a design flop repeated by many designers over and over again throughout the 1960's and into the early 1970's, including the Motorola HT220. A round push-to-talk button near the top on one side completed the strange appearance of this ugly two-tone radio. The Pocket Mate was made only in VHF versions and is rare. They were also made under Bell & Howell and Kel-Com brand names in a dark, solid gray color style. The Pocket Mate was the radio found in the possession of the Watergate burglars during the famous Nixon era Watergate debacle. Some were apparently also used by the Secret Service and various covert agencies, which in retrospect leads me to pity them a bit for having to use what I think is a silly looking radio. For reasons unknown, the Pocket Mate and its relabeled versions are very rare today.

GE introduced the Porta Mobil in high and low band models in April, 1964, at which time it contained the industry's first fully solid state 10 Watt transmitter.

The Porta Mobil was a solid state pack set intended to replace the Progress Line series portable, rather than the Voice Commander, in that unlike the Voice Commanders, it is larger and has a metal housing. The top handle is a spring-loaded affair which pulls up when grasped, then retracts when released. I am thinking that perhaps there was a major design department employee change at GE about 1964, when the "silly" looking radios stopped being made.

The Porta Mobil is fully solid state with a power supply which is an up - converting DC-DC converter, bringing the battery or input voltage to 36 Volts for the transmitter power amplifier stage. The Porta Mobil is actually heavier than the Progress Line portable, but runs a nominal 18-20 Watts on low band and 12 Watts on UHF and high band. The speaker audio output is quite high compared to previous pack sets. The Porta Mobil, being a MASTR series radio, has a centralized metering jack. It uses all silicon transistors. This set was available in either battery powered portable configuration, DC only power supply operation for mobile use, or an AC power supply for base station operation.

There was a steel mobile mounting tray to allow mounting of the radio in a vehicle, and a remote mount industrial version was also available, after May, 1965, usually used as a motorcycle radio within an appropriate rear-fender weather housing. The standard model featured a microphone, but a handset version was available. Two frequencies were as many as normally available, although a four channel model was made. The Porta Mobil was available in low, high and UHF bands and was purchased in large numbers by forestry and fire departments, logging and industrial buyers. The motorcycle version is rare today, as apparently few were made. The Porta Mobil has no quirks and is generally regarded as a high quality, reliable radio, other than needing a higher than expected amount of battery power on transmit. The knobs are frequently found broken or missing, and they are one area where a bit better quality could have been applied. A "Porta Mobil II" was introduced in approx. 1973 to replace the original Port Mobil.

Porta Mobile Motorcycle and Industrial Extended Control Head

MASTR Series (1964-1973)

MASTR Professional

The MASTR Professional Series began production in late summer 1964 and totally replaced the TPL, Accent and Pacer series as well as the remaining Progress Line models. The MASTR Professional series was quickly added to by an economy version bearing no similarity, called the MASTR Executive Line. By the late 1960's there was also the Custom Executive, a dash mount radio, and several other MASTR sub-models.

MASTR Professional became to the 1960's what the Progress Line had been to the 1950's, and probably saved GE's mobile radio business from disaster. The "MASTR Pro" is generally regarded as one of the finest mobile radios made by any manufacturer during the period. Unlike the TPL, the MASTR Pro series returned to the philosophy of the Progress Line in terms of separate power supplies, receivers and transmitters made in long chassis "strips." Unlike the Progress Line, the MASTR Pro strips were tied together at the ends with a cast front plate and a rear mounting plate, with individual covers (top and bottom) on each strip with a gap between the strips. This is as opposed to the single large "drawer" housing as used on the Progress Line or the screwed-together modules of the TPL. As viewed from the front, the MASTR Professional series chassis are, from left to right, receiver, power supply, and transmitter. Accessory chassis were usually placed across the rear apron.

The MASTR Pro equipment was available for all conventional bands as well as export and special service bands, in many different power levels. The UHF Mastr 60 Watt series was not ready for production until January, 1965. There were many "specials" with assorted options such as more than four channels, multiple channel guard operation, dual receivers, dual receiver front ends, scan, etc.. One of the more famous "specials" is the Illinois State Police Radio Network, or "ISPERN" radio, recognizable by its red microphone and multiple pilot lamps on the control head representing the channel in use.

The initial MASTR Pro series featured a solid state receiver with 2 Watts of audio, and a hybrid transmitter containing a solid state exciter and miniature and Compactron tubes in the power amplifier section. Up to four frequencies were available on the standard boards, and multiple channel models were available on special order for more than four channels. Later receivers were brought up to five watts of audio power output, and the last series used TCXO oscillator modules on VHF and UHF. Like the Progress Line, the "strips" from the MASTR Pro series could also be used in base stations, of which there were several configurations. MASTR Pro mobiles could have the control head mounted directly to the front of the rather large radio assembly, or used under the vehicle dash as was most commonly done. The early control heads were made of die cast metal while the last series were gray molded plastic. All of the MASTR microphones were Shure plastic housing types made for GE with a unique housing design.

By the late 1960's GE offered fully solid state versions called the MASTR Imperial and MASTR Royal Professional, to compete with Motorola's Motran series. These last-generation MASTR Professional radios typically used TCXO modules for frequency stability, called ICOMs in GE parlance, and were rather cutting-edge in design. They were and are uncommon.

GE's advertising often showed the MASTR Professional as a front mount configuration, although the arrangement was so massive (much larger than the TPL) that few were ever configured that way.

There were two styles of speaker one is as shown below with an all plastic front housing, and an earlier design with a perforated aluminum screen and a cast metal front housing. It is presumed that the change to a plastic speaker housing occurred at the same time that the control heads changed to plastic housings. There were also many custom control head faces made for special customers the typical generic control head is the only one shown here. A "scan" head was also manufactured, which contained a four channel scanner in a deep housing.

All of the MASTR Professional heads contain a "standby" position on the power switch, which de-energizes the transmitter filaments to save vehicle battery power when there is no need for instant transmission capability, allowing the vehicle engine to be shut off for extended periods of monitoring.

The Mastr Professional series, based on serial number tags, seems to have still been in production through 1973 although the Mastr II was also being sold by 1970.

MASTR Executive (1965-1973)

The MASTR Executive was a cheaper alternative to the Professional series but enjoyed an equal reputation for reliability and durability. It was introduced in December, 1965 for VHF high and low bands, with a UHF version following approximately two years later. The receiver chassis of the Executive is a metallized plastic, and the transmitter is a hybrid design similar to the Professional series, using Compactron style tubes and conduction heat-sinking. The Executive radio is in a unitized package about 1/3 the size of the Professional, but was available with fewer options. The Executive was available with a small control head mounted to the front of the mobile drawer, where the control cable connector would normally be, or a separate dash mounted control head. Executives were very popular with RCC organizations and budget-minded customers. As with the Professional series, the last generations of the Executive had fully solid state transmitters and TCXO modules, and were referred to as the Royal Executive. The Executive series was available in all bands and several power levels. The Executive control heads were a cheaper design than the Professional, and featured no squelch control, instead having only a "Monitor" white pushbutton.

The Executive was a reliable, relatively trouble-free radio, despite its somewhat "cheap" construction.

Unlike the MASTR Professional, which requires a heavy mounting "tray," the bottom half of the Executive mobile housing has holes and a raised boss to allow it to be used as the mounting platform.

Both the Professional and Executive series would be replaced in the 1970's by the MASTR II and Executive II series radios, respectively, of substantially different design, with remaining stocks of both product being sold through approximately the end of 1973.

Below is a typical example of the Executive mobile drawer, from 1967 .

Executive series accessory group. Note that the microphone hang-up clip was not normally located on the control head this was a customer-performed modification.

Metallised yarn - A case on classification

An importer praying for levy of higher amount of customs duty makes for a very good yarn. The case Best Key Textiles Ltd v. United States may not have settled the issue for once and for all as to what is metallised yarn but it provides an interesting insight into arriving at a classification and whether it can be argued that levy of lower customs duty is a trade rather than revenue tool.

Briefly, the plaintiff had submitted samples of yarn which was initially classified under 5605.00.90, Harmonized Tariff Schedule of the United States (HTSUS), which provides for metalized yarn, whether or not gimped, being textile yarn, combined with metal in the form of thread, strip, or powder or covered with metal Other. However Customs authorities later revoked this ruling and classified the same under Heading 5402 holding that the yarn was of polyester which attracted a lesser rate of duty. This somehow inconvenienced the plaintiff since garments using metallised yarn were subject to lesser rate of duty and made its ‘polyester’ yarn unattractive.

Apart from the issue of classification the case has also witnessed a number of challenges on account of procedural lapse, insufficient notice of revocation to the plaintiff following a shutdown in US government and so on. However, two aspects of the challenge are very interesting, the classification per se (for various combinations of arguments) and the plaint that the revocation was arbitrary and capricious.

The element of metal present in the product – how material

The process to produce the yarn was described as melting polyester chips into a slurry to which aluminium or zinc powder and titanium dioxide (a delusterant which reduced the sheen of the fabric) and then firing the slurry through a spinneret to produce the yarn. The plaintiff argued that the presence of metal in howsoever small the quantity, since no threshold was prescribed, would entail classification of the yarn as metallised. However, Customs held that ‘combined with metal’ required more than mere presence of metal along with the textile yarn. It also laid emphasis on the fact that the state in which the product is imported rather than how it was manufactured would determine classification.

When Explanatory Notes provide for specific exclusions

Referring to the explanatory notes (EN), it held that not every mix of yarn and metal would automatically qualify for classification under Heading 5602 since the EN refers to use for lace and trimmings. Thus, metallised yarn was used for decorative purposes and as commercially understood had visible metallic appearance. The court was persuaded by the argument that though the Heading 5602 was clear, in view of the specific exclusion in the EN to items like yarn reinforced with metal thread, not all forms of metal-yarn combination would fall under 5602.

Introducing metal in the process to prepare yarn is sufficient…

The plain reading of Heading 5602 did not seem to help the importer much. Seeking to bring the product with 5602, the plaintiff put forth an argument that Heading 5602 encompassed both decorative and non-decorative properties . Hence, addition of nanometals to the slurry, of which some residue remained and which imparted certain qualities like ultraviolet protection, would be sufficient to constitute metallised yarn. However, this argument too fell short since, such addition in quality was not measurable and it stretched the scope of the heading way beyond legislature’s intent.

For instance, in a previous ruling, Customs had not held a yarn to be metallised merely because there was some metal content. A fabric comprised of 45% cotton, 47% polyester and 8% steel which imparted protection from microwave radiation, it was not classified under 5602. There the reasoning was that combining textile and steel fibre would not make for metallised yarn. This perhaps spoke for consistency in the reasoning of the authorities that ‘combined with metal’ and satisfying the EN was essential for a product to qualify under 5602.

The court however, refused to go into the real reading of the heading. Being a judicial review of revocation ruling the court adhered to what is called the Skidmore deference and examined the ruling for consistency of customs’ approach and whether the ruling had the power to persuade.

Combined – state of being combined or process of combining

Another point of dispute was whether ‘combined with metal ‘referred to state of product or process of manufacture. While it was conceded that new methods of manufacture of yarn may still be evolved and newly developed products could still qualify under 5602, the nature of the product and not the new methods of producing the same was held to be important. In its finding Customs recorded that what was understood as metallised yarn was either textile coated with metal or metal sandwiched between layers of plastic, etc., which served a decorative purpose.

Consultation with commerce bodies, experts arbitrary

The plaintiff then attacked the consultations by Customs with various bodies, domestic industry, etc. It wanted to impress upon the court that such consultation with competitors and others who did not employ similar processes had influenced the ruling. However, it was obviously difficult to prove that only lobbyists and competitors had been consulted and they had influenced the decision. The Court concluded that Customs could seek assistance of experts or domestic industry to arrive at the classification.


The inspiration for my first solo exhibition Strips of History comes from costumes worn from the ancient Egypt to the 19th century Romantic period. For me, this inspiration was an inevitable choice since I have been fascinated by the history of fashion, conducted my own historical research in the field of fashion history and taught history of costume for many years. My works not only incorporate the ideal beauty represented in the dress of the past, but also capture that of today. Just as many strips from history were woven together symbolically to create new designs, each work truly consists of long strips of fabric they are cut from woven fabrics and hand-knitted ones. Selected colors are black, white, purple and gold. Purple and gold are chosen because they have long been known as colors of privilege, symbols of wealth and high social status. The crucial goal of this exhibition was not only to convey the essential beauty from the past to the present time, and but also to illustrate that “past is the greatest prophet of the future.”