Most metallic stripes are not metal thread. They are plastic film carrying a very thin aluminium layer, slit into fine strips. That layer cracks where the fabric bends, wears off under abrasion, and is attacked by alkaline detergent and chlorine bleach. Specify a laminated, coated yarn, ask for its fastness data, and wash-test the garment before bulk.
The complaint is common on party dresses, tops, kaftans and resort wear with lurex stripes or checks. It also shows up on embroidery worked in metallic thread. The stripe looks bright on the sample. After a few wears and washes it turns grey, see-through or patchy, and small flecks of shine come off. Each of those symptoms has a specific cause, and most of them can be dealt with on the order.
What is the shiny stripe actually made of?
In most garments it is aluminium on a plastic film, not solid metal. Two constructions are common:
- Laminated: aluminium is sealed between two layers of acetate or polyester film, then cut lengthwise into strips (Wikipedia, Metallic fiber).
- Metallised: the metal is vaporised and deposited onto polyester film. The same source says this gives thinner, more flexible fibres. Aluminised nylon is also used.
Colour comes from tinting the metal, the adhesive or the film. A clear gold film over silver-coloured aluminium reads as gold. “Lurex” is a brand name. The Textile Research Centre in Leiden notes it became a generic term for laminated metallic threads, so the word on a spec sheet does not tell you which construction you are getting.
The flat strip is often wrapped around a core yarn of polyester, nylon, viscose, cotton or silk. That is how zari is built, whether the strip is gold, silver or slit metallised polyester film. The same Wikipedia article separates three grades: real zari (silver or gold), imitation zari (copper wire plated with silver) and metallic zari (film).
Embroidery thread follows the same pattern. Madeira’s FS No. 50 is sold as a “metallised embroidery thread” of 55% metallised polyester and 45% polyamide (Madeira data sheet).
| Type | What gives the shine | Main way it fails |
|---|---|---|
| Real metal thread (silver, gilt silver) | Solid metal strip or wire on a core | Silver darkens as silver sulfide forms (Canadian Conservation Institute) |
| Metal-coated thread (copper plated with silver) | A plated layer on copper | Silver and copper both tarnish; sterling silver tarnish contains copper sulfide (same CCI source) |
| Laminated film yarn | Aluminium sealed between two films | Cracking at bends; edge and surface wear |
| Metallised film yarn, unlaminated | Aluminium deposited on one film | Metal layer rubs and washes off; fabric looks transparent (Altas et al., 2020) |
Film yarn is lighter and cheaper than real metal, and it does not blacken the way silver does. Its weak points are different: the metal layer is extremely thin, and aluminium has its own chemistry.
Why does it crack or flake at bends?
Because the metal layer is far thinner and stiffer than the film under it, and every fold stretches its outer face. The film bends and recovers. The metal layer does not recover as well, so it cracks.
Research on thin metal layers deposited on textiles shows how this progresses. In a cyclic bending study, Korzeniewska et al. (Scientific Reports, 2020) saw single cracks appear on the layer first. With more bending, the main change became the widening and lengthening of cracks that already existed. That study used silver and gold layers made for conductive textiles, not lurex. The mechanism is the same: a thin, brittle coat on a flexible base.
Once a crack opens, the edges are exposed. Water and detergent reach the aluminium from the side. Abrasion lifts the loosened flakes. That is why the damage on a garment starts where it flexes most:
- underarms, elbows and the inside of sleeves;
- waist seams, gathers, smocking and shirring;
- hems and side seams on kaftans and maxi dresses, which fold and rub every wear;
- embroidery, where the thread is bent tightly around each stitch.
Lamination helps. In a study of fabrics knitted from metallised yarns, Altas, Yilmaz and Adman (Journal of Industrial Textiles, 2020) found that repeated washing and abrasion removed the metallic layer, so fabrics lost their shine and looked transparent. Laminating the metallised film significantly improved resistance to repeated washing and to abrasion. Polypropylene films gave the best results, though with a harder handle than polyester.
Why does it go dull or dark over time?
Film yarn usually goes dull, grey or see-through as the aluminium is attacked or worn away. Real silver and copper-based threads go dark because they tarnish.
Aluminium protects itself with a thin oxide layer, about 5 nm thick at room temperature (Wikipedia, Aluminium). That layer has two known weaknesses. Aluminium reacts with aqueous sodium or potassium hydroxide to form aluminates, and passivation then stops protecting it. It is also corroded by dissolved chlorides. When the metal goes, the mirror goes with it. What is left is clear or tinted film, which looks flat and grey against the fabric.
Real silver behaves differently. It reacts with sulfur gases in the air to form silver sulfide, the dark tarnish layer (Canadian Conservation Institute). This happens on the hanger as well as in the wash. So a stripe that has turned dark brown or black is more likely real or plated metal. A stripe that has turned pale and transparent is more likely film.
Not every film yarn is equally stable. Madeira’s FS No. 50 data sheet says six named shades “might oxidize” while the other shades are resistant to oxidation. Its FS No. 12 sheet states that all colours in that range are resistant to oxidation (Madeira FS No. 12). The protective top film is what makes the difference. Wikipedia notes that metallic filaments can be coated with transparent films to minimise tarnishing.
Which wash and dry conditions wear it fastest?
Alkaline detergent, chlorine bleach and mechanical rubbing do the most damage, and they are worse together.
Alkali. Washing powders are alkaline by design. A detergent patent states that granular laundry detergents are typically formulated to give a wash water pH of about 9.8 to 10.5 (EP0456315B1). Aluminium’s oxide dissolves in both acid and alkali, so it holds up best near neutral, and alkali attacks the metal itself. Each wash reaches any aluminium exposed at a crack or a cut edge.
Bleach and chlorine. Hypochlorite bleach brings both chloride and alkalinity, the two things aluminium’s oxide layer resists worst. Tolerance varies by yarn. Madeira’s FS No. 50 carries a crossed-out bleach symbol. Its FS No. 12 is rated 4-5 for fastness to hypochlorite bleaching, but only within a stated limit: max. 20 g/l active chlorine, max. 30°C, max. 30 minutes. Chlorinated pool water is a separate exposure for resort wear and swim cover-ups. Wikipedia says suitable adhesives and films can make metallic fibres resistant to chlorinated water. The yarn’s own data has to confirm it.
Abrasion. The metal layer can rub off. Madeira rates rubbing fastness on FS No. 50 at 3 for gold tones and 4 for silver tones, on a 1 to 5 scale where 5 is best. Gold tones are the weaker of the two there. A tumble dryer rubs garments against each other and against the drum for the whole cycle. Long agitation in a full machine does the same. Zips, hooks and sequins on the same garment scrape the stripe from the inside.
Heat. Pressing and heat-setting are covered in our post on scorch and shine on cotton, linen and viscose.
The gentlest routine follows from the chemistry: cool water, a mild detergent, no bleach, short cycle, garment turned inside out or in a mesh bag, and line or flat drying.
What should the order or tech pack say, including testing before bulk?
Name the yarn construction, ask for the yarn maker’s fastness data, set the care label, and test the made-up garment before bulk.
1. Name the yarn, not just “lurex”. The tech pack should state:
- laminated or metallised film, and the base film (polyester, nylon or other);
- whether it has a protective top coat or lamination;
- whether it is a flat strip or wrapped round a core, and the core fibre;
- the supplier’s article number and shade, so the bulk yarn matches the approved sample.
2. Ask for the yarn data sheet. Madeira’s sheets list, among others:
- ISO 105-C03 or C04: colour fastness to washing at a stated temperature;
- ISO 105-N01: colour fastness to hypochlorite bleaching. Its scope covers textiles bleached with hypochlorite at concentrations normal in commercial bleaching, with colour change rated on the grey scale (ISO 105-N01);
- ISO 105-X12: rubbing fastness, done dry and wet against a white cloth;
- ISO 105-D01: colour fastness to dry cleaning.
Ask for these ratings for the exact shade. Ask directly whether the shade is resistant to oxidation.
3. Test the garment, not only the yarn. A yarn rating says nothing about a stripe that sits in a gathered waist. Before bulk:
- wash a made-up sample through repeated home-laundering cycles. ISO 6330 sets out domestic washing and drying procedures for textile testing. Agree the procedure, detergent, drying method and number of cycles with the lab;
- compare the washed sample with an unwashed one under the same light, and look closely at the bends;
- for fabrics where wear is the concern, ISO 12947-4 uses the Martindale method to assess change in appearance after abrasion;
- keep the approved, tested sample as the reference for the top-of-production sample.
4. Design for the yarn. Keep heavy metallic areas away from the hardest bends where the style allows. On embroidery, check the thread maker’s recommended needle size. Madeira lists one for each thread on its data sheets.
5. Write the care label to match. State “do not bleach”, a cool wash, wash inside out, and no tumble dry if the test result calls for it. The label should reflect what the garment passed, not a generic line. Our guide to creating a tech pack covers where these lines sit.
Working with KK Fashion Exports
KK Fashion Exports has made women’s garments and scarves in Noida, India since 2003, for buyers worldwide. We make dresses, tops, kaftans and resort wear, including styles with lurex stripes and metallic embroidery. Orders for dresses, kaftans and other garments start from 200 pieces per style, per colour. Send us the style and the yarn details with your enquiry.
Developing a womenswear range? See how we work as a ladies garments manufacturer in India.
View the B2B lookbooks → a glimpse of our latest collections. Request the full range: more designs on request.
