Fiber - Specific Gravity

Fiber	Specific Gravity
Acetate Rayon	1.30-1.33
Acrylic	1.14-1.18
PVC	1.38-1.70
Glass Fiber	2.50
Modacrylic	1.31-1.37
Nylon	1.10-1.14
Polyester	1.22-1.38
Polyolefin	0.90-0.95
Cupramommum Rayon	1.52
Viscose Rayon	1.52
Carbon High Modulus	1.77
Carbon Ultra High Mod	1.96
Alpaca	1.31
Angora Rabbit fur	1.10
Camel Hair	1.31
Cashmere	1.31
Cotton- Solid Fiber	1.54
Cotton Overall fiber	1.35
Linen	1.50
Flax	1.50
Hemp	1.50
Jute	1.50
Mink	1.26
Mohair	1.31
Musk Rat	1.26
Rabbit-Common	0.92
Ramie	1.55
Silk Weighted	>1.60
Silk- B. Mori (Raw)	1.33
Asbestor	2.1-2.8
Silk- Tussar	1.32
Wool ( non-modullated)	1.31

Word Origins of Some Textile Terms

Cotton

Cotton originated in Arbic qutn, the name for cotton plant.

Silk

Word silk originated in Chinese si. Greek called Silk traders Seres, "silk people". This is the origin of the words like Sericulture and Serge. 

However, the 'l' rather than an 'r' came through Russian Shelk.

Linen

The word comes from old Germanic "lin" meaning "Flax"which is an origin of the words such as linseed.

It has contributed to other words such as Lingerie, crinoline, linoleum and lint. 

Wool

It came from Indo-European "wlna". the word flannel is related to it.

Source: Bloomsbury Dictionary of Word Origins by John Ayto.

Spinning

Spin comes from Indo-European Base "spen" which means to stretch. The logic seems to make sense as spinning essentially involves stretching or drafting of a strand of fibers.

The words span, spinster, spider, spill and spindle are related to it.

Weaving

The origin is from Germanic "Weben"- to weave. This is the source of the words wafter, wasp, web and weft. 

Dyeing

The source of this word remain unknown.

Printing

The origin comes from Latin "premere" meant press. The words impression are related to it.

Bleaching

The origin comes from Germanic base "blaik-"means to whiten. The words blight and blink are related to it.

Textile

Latin texere means to "weave" which came from Indo European base "tek-" to make. It is the origin of the words text, context, pretext, subtle, texture, tissue and toilet, technical and architect.

Cloth

The history of the word cloth is Germanic "kleid"- means garment.

Fabric 

The word fabric is related to carpenter. The origin is the word "Faber" which means a carpenter. Other related words are fabricate and forge.

Apparel

It has the same source as apparatus, which came from apparare "make ready". The other related words are parent and prepare.

Yarn

The root came from prehistoric German "garn" which is originated from Greek "Khorde"- sting. The other related words are chord and cord. 

Fashion

The word came from Latin factio "make" or "do". The words related to it are difficult, fact, faction and factory. 

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What is TR Fabric

TR fabric refers to Terry Rayon, a fabric made with a polyester/viscose blend yarn. Generally it is used for suitings.

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Is Art Silk a type of Silk ?

This term made popular by catalog-centric websites is a misnomer. Art Silk in the technical circles, is a synonym for rayon.

However, now art silk is a euphemism for the articles made in polyester, nylon or acrylic.It is also known as polysilk.

One can find out the difference between the real silk, rayon and the "art silk" ( nylon, polyester, and acrylic) by burning a small yarn from the fabric and identifying the bead and smell.

See Also

Fiber Identification of Man-made fibres

Fiber Identification of Natural Fibers

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What is the difference between Faux Georgette and Georgette

Faux georgette is a nice way of saying that a fabric is made of polyester or nylon Georgette.

This term is used very frequently in e-commerce, where customers are normally get offended by the term "polyester" and marketers don't want to offend them.

"Faux"- as described by Google ( Search for the word "faux") means artificial or made in imitation.

Taking the above definition into account the word "faux" is more misleading as the Georgette is genuine.

In this sense calling a fabric faux Georgette, or faux Crepe or faux Chiffon is a faux pas in technical terms.

Conclusion: If you find "faux" written before a fabric, assume that it is synthetic ( polyester or nylon).

See Also:

Difference Among Chiffon, Crepe, Georgette

What is 8 Kg Georgette

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Difference Among Pure Silk, Blended Silk and Part Silk Fabrics

As per BIS (Bureau of Indian Standard) the following definitions will apply. Please note that composition of only ground fabric or base fabric will be considered.

1. Pure Silk

If the content of silk in the fabric is more than or equal to 95% then it is termed as pure silk.

2. Blended Silk

If the content of silk in the fabric is more than or equal to 50% then it is termed as blended silk. A tolerance of +-3% is allowed on the declared content.

3. Part Silk

If the content of silk in the fabric is more than or equal to 20% then it is termed as part silk. A tolerance of +- 3% is permitted.

As per BIS, a silk fabric to be marked with the following information among others:

a. Name of the fabric eg. chiffon, crepe etc.
b. Blend composition e.g. pure silk, blended silk or part silk
c. variety of silk eg. mulberry, eri, muga or tussar

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Learning about Viscose, Modal and Tencel

The production process of the three fibers has been convered elsewhere in the blog. Here I would like to discuss some of the properties useful for fabric buyers for comparison.

In dry state viscose is only slight weaker than cotton. However, in the wet state, the strength is about 38% that of cotton. That makes it a very tricky fiber to blend with cotton and subsequent dyeing with cotton. The fabric undergoes changes in shape when wet processing.

Also strength of cotton increases when wet- being 1.14 times that in dry state. However, for viscose it is about 0.5 times that in dry state. This necesssitates that the viscose should be dry cleaned rather than ordinarily washed.

Modal's strength is comparable to cotton in dry state. In wet state, it is about 78% of the cotton strength. For Tencel, it is much more than cotton both in dry and wet state.

A table comparing the properties of the three is given below:

The above table represents three fibers from Birla. VSF is the first generation viscose. Modal is second generation and Tencel is the third generation viscose.

This Link describes the precautions to be followed in viscose processing.

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Cotton Price Trends in India

Indian Textile Mills are ramping up imports of cotton

Source: seedrack.com via Melyssa on Pinterest

Mills in India, the world's second biggest cotton producer have already imported 500,000 bales and have signed contracts for around 1 million bales at 75-80 cents per lb, compared with the local price of about 88 cents. This can be attributed to the following two reasons. 

a. Tight Domestic Supplies of Cotton 

- Poor rainfall in top producing Gujarat State. Saurashtra and Kutch regions of Gujarat, the country’s largest producer, have received 72% less than the usual rainfall by this time

- A rally in Soyabean prices is prompting some farmers to ditch cotton for Soyabean.

- Record export of good quality cotton earlier this year, with lower quality cotton left this year. 

- Harvesting is getting delayed because of late arrival of Monsoon. If it gets delayed beyond Sep, the domestic cotton prices will sky rocket. 

b. Lower Prices Abroad

- Domestic cotton prices are ruling around 88 cents per pound, freight on board, around 14% higher than the African fibre and 10% than the crop in the US, the world’s largest cotton exporter

Source 1

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A Layman's Review of Silk

What is Silk

Silk is a continuous protein filament secreted by specific types of caterpillars commonly known as silkworms. It is the most loved fiber the world over. Natural sheen, inherent affinity for rich colors, high absorbency, lightweight (yet stronger than a comparable filament of steel), poor heat conduction ( warm in winter, cool in summer), low static current generation, resilience, and excellent drape are some of its irresistibly endearing qualities. 

Varieties of Silk

Mulberry

This is the most commonly known and understood form of natural silk. 

Mulberry silk is light weight, has a natural sheen and smooth feel. Majority of finished silk products available in the market are made from mulberry silk. 

The mulberry silk worm feeds on mulberry leaves and forms a smooth cocoon, from which yarn is taken out through a process called reeling. 

Mulberry silk is a rich absorbent of colors and is a printer's delight. 

Vanya Silks or Wild Silks ( Tasar, Eri and Muga)

India's Wild Silks or Vanya Silks reflect the exotic and untamed spirit of wild silk worm...in texture, feel, sheen and color. It has inspired designers to create distinct fashion statements in clothing and home textiles. 

Vanya Silks have baffling thermal properties, keeping warm in winter and cool in summer. 

Vanya Silk portray the rich crafts culture and folklore of the North Eastern and Tribal zones of Central and Eastern India. They are of three different types, each distinct in its characterisics, Tasar, Eri and Muga. 

Tasar 

The tropical or Indian Tasar Silks are highly textured and have a wide range of natural colors from off-white to beige and gold brown. It has a dull, uneven sheen and can also be dyed in a number or colors and easily blended with cotton, wool, linen or other silks. 

Well known Bafta fabric is a blend of India Tasar with cotton. Tasar is used in both spun and filament form. Tasar silkworms feed mainly on Asan and Arjun leaves. India is the second largest producer of Tasar silk in the world. 

Desi or Indian Tropical Tasar is produced by the species of worms known as Antharaea Mylitta. There is another variety of Tasar which is called Oak Tasar. It is produced by another species of worms called Antharaea Proyeli (produced in India ) and Antharaea pernyi (produced in China). It is a finer variety of Tasar.

Eri

Also known as Endi or Errandi Eri silk is produced by Eri silkworm, which mainly feeds on Castor and Kesseru leaves. 

Eri can be spun in coarse to very fine yarns and is home washable. It can also blend with cotton, wool, jute and mulberry silk. 

Eri silk gains better sheen with every wash. Its high warmth retention makes it very comfortable in cooler climes. It is popularly used for making Shawls, Stoles, Fashion accessories and Home Furnishings. 

Muga

The shimmering golden color, distinct look and smooth feel of muga is an instant inspiration to the interior, home and fashion designers all over the world. Muga commands highest premium amongst all silks. 

Reared in Assam, the Northeastern region and Cooch Behar in West Bengal, Muga silkworms feed on Som and Sualu Leaves. 

Muga yarn is generally used in the Assamese homes for home furnishings. The famous Sualkuchi sarees too are a product of Muga silk. 

Silk Care

Precautions during washing ( Source : Silkmark Brochure- Please try separately before following instructions)

1. Always wash silks in soft water. Add a pinch of Borax or ammonia, if the water is hard. 

2. Use a good neutral soap in the forms of either flakes or solutions. 

3. Light detergent may also be used in the case of hard water. 

4. Wash in lukewarm water by kneading and squeezing or suction. 

5. Rinse in warm water 2-3 times to remove traces of soap.

6. Add a few drops of citric acid or acetic acid to the final rinse in cold water. 

7. Silk with doubtful color fastness may be steeped in cold water with a small amount of citric or acetic acid for 1-2 minutes before washing. Squeeze lightly by hand to remove water. 

8. Always dry flat, in shade. 

Precautions during Ironing

1. Use Low to medium heat

2. Never spray water to dampen silk before ironing. This will cause water spots in the fabric. 

3. Silk should always be ironed on the reverse side if still damp.

Storage of Silk Products

1. Store in cool and dry place in brown craft paper covers. 

2. In case of sarees avoid stacking more than three, frequently reverse and change the folds. A small sandal wood piece instead of naphthalene balls would provide dry, cool and fresh air. Sweat should never be allowed to settle and should be removed by rinsing in cold water. 

3. Hang the silk products in good ventilated wardrobe or cupboard.

4. Use anti-mildew compound spray.

5. Warp in muslin cloth to avoid discoloring of zari. 

6. Use natural perfume like Sandalwood swatch for refreshning.

7. Plastic bags given as package material after laundering or purchase should not be used for storage. 

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Difference between Blended Fabrics and Union Fabrics

Blended Fabrics are made up of blended yarns. Blended yarns contain fibers of different composition in fixed proportions. Thus a blended fabric may be made of polyester/cotton in 67:33 ratio in both warp and weft. 

Union fabrics are the fabrics where in the fibre content of warp is different form that of  weft. Thus a Silk/Viscose union fabric may have silk in the warp and viscose in the weft. 

An excellent study on silk/viscose union fabrics can be found here. 

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Bamboo Fiber- I

Bamboo is a regenerated cellulosic fiber. There are three types of bamboo fibers:

1. Pure Bamboo

2. Bamboo Charcoal

3. Bamboo Viscose

1. Pure Bamboo

Pure bamboo is produced by physical and mechanical process like linen and hemp. It has high strength and is environment friendly. However it suffers from poor spinnability properties and high cost.

2. Bamboo Charcoal- An application of Nano Technology

In making this fiber, the bamboo is dried and heated at 800 deg. C until it becomes bamboo charcoal. Then the charcoal is sent for further processing to turn it to nano particles. These ultra fine bamboo particles are then embedded into viscose or polyester fiber. The fiber is then drawn into yarn and processed as usual.

Generally nano-bamboo charcoal powder is added during the process of spinning solution.Thus polyester, nylon and viscose fibers can be manufactured embedded with bamboo charcoal fiber.

This fiber has strong adsorption capacity.  It can adsorb bad odor and chemicals. It shows an excellent anti-pilling tendency and the material washes well. It has strong anti-microbial properties. In an actual test of a pair of socks, after wearing without washing for a week, the socks not only have no odor, they were also dry. The disadvantage with this fiber is that it is only available in grey and black colors.

Source 1 2 3 4

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Linen and Ramie

These nuggets of wisdom about Linen Fabric I have gathered from the website of Jayashree Textiles of Aditya Birla Group:

1.Linen was extensively used in the mummification process by the ancient Egyptians, as it helped preserve the dead body and to this day remains of some important mummies have their linen coverings intact.

2. In ancient Celtic times, linen was spun in an anti-clockwise direction as it was believed that this endowed mystical powers bringing the weaver good fortune

3. Scientists have recently discovered, cutting linen that was preserved in the British Museum woven 6000 years ago, is structurally perfect just as any new linen today. This reveals that linen has the ability to resist the effects of time and that linen is not affected by germs.

4. The word ‘spinster’, meaning single woman comes from the time when flax was still spun on spinning wheels by women. This skilled work was considered as an advantage when looking for a suitable husband. Single women were encouraged to sit outside and spin, so that they could be admired by potential suitors as they passed. As a result, the word gradually became associated with single woman.

5. ‘Flaxen hair beauty’ comes from the beauty of the flax fiber, which resembles golden hair.

Then there is a “caution” of confusing Linen against Ramie and other synthetic fibers and cotton slubs;  this reads as follows: 

1.   Ramie is being sold as Linen in India whereas Ramie is not Linen. 

2.   Ramie the Produce of China gets harsher after every wash and itches to the skin, whereas linen fabrics gets softer after every wash and becomes very much soothing to skin.

3.   Further cotton slubs, polyester slubs fabrics are also not linen, however they are being sold as linen misleading to the consumer.

A search about the Ramie Fiber and its comparison to Linen revealed to me an amazing treatise on the other natural fibers, which by itself very helpful but unfortunately deals very less with ramie and their potential for India. On probing further, I came to know this article on Ramie fiber.

A site selling Ramie fabric talks about “100% Ramie Linen Fabric-Ramie is a fiber similar to linen. In fact, it is almost impossible to tell the difference between this fabric and the most expensive linen”.

I just wonder what would be the price difference between these two fabrics. Ramie is reported to be twice strong than Linen.

A very useful article comparing Linen with Ramie says the following among other opinions: "Textiles made from ramie behave similarly to linen textiles. They are prone to wrinkling and will breakdown if sharply creased, so it is best to fold them loosely and store flat. One advantage ramie has over linen is that it is naturally bacteria- and mold-resistant. It holds dye well, although saturated colors can be prone to crocking, which is discoloration of skin or other fabrics that contact the dyed ramie at stress points or wet areas. Ramie 

can handle the same heat and agitation as linen."

A further research article says that “ Ramie is the strongest bast fiber and one of the strongest natural fibers comparable to cotton and silk. In terms of length to breadth ratio, whose higher value indicates better fiber quality, is even greater than cotton and linen. However Ramie is stiff and brittle with low elasticity".

I feel that Ramie has potential to be another fiber of the future

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More about Tussar or Tussah or Tassar

Looking for Tussar, I came across several other interesting features. Some of these are as follows:

1. China exports two types of Tussar Silks: 33/37 D Water reeled and 70 D Dry Reeled Silk. I am just wondering if the "China" that is 50/70 quality that we use in India is dry reeled always.

2. There are 7 grades of quality of Tussar Exported by China, 4A, 3A, 2A, A, B, C and Off grade.


3. The standard moisture regain of Tussar Silk is 10% and density is 1.58 to 1.63 gms/cm3.


4. Elongation at break of water reeled tussar is 23% and dry reeled tussar is 16%.


5. China tussar is different from Indian ( Tropical ) tussar due to the fact the China Tussar the species of the worm is different and fed on "Oak Leaves" ( Also done in Himalyan Regions of the country). Whereas in India it is fed on "Arjun" and "Aasan" leaves. 


6. 8 is the usual number of cocoon filaments to form a single thread. The normal size of the thread produced is 30-35 deniers.


7.Tussar silk is the primary kind in the silk which lustrous,bright,soft handfeel,it has highest wear resistance in the natural faric. The Acid & Alkali Resistance of tussah silk is better than mulberry silk.


However I could not find out how they do dry reeling of tussar. Would require your inputs. 


And yes, I found the Tussar process practiced in Bihar, Bhagalpur. You can click here to find out more.

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More about Silkworms and Silk fiber- Mulberry, Muga, Tasar and Eri

Silkworm belong to the order Lepidoptera. They belong to family of Bombycidae and Saturniidae. Under Bomycidae, we have Bombyx Mori or commonly known as Mulberry Silkworm. Under Saturniidae family the eri silk worm is called Philosamia Ricine, Muga is called Anthrerea Assamensis and Tasar is called A. Mylitta. 

Silk filament is made up of 75-80 percent fibroin and 20-25% sericin or gum. Fibroin is insoluble but sericin may be removed by boiling. 

The Muga and Tasar varieties of the worm also secrete a cement which causes a drab color to develop, making bleaching a very laborious process. 

Silk of the B. Mori variety is triangular in cross section. It has a capacity to reflect light and the layers of protein impart it with a pearly sheen. Tasar silk has a flatter structure which is a reason for its dull appearance. 

Muga is rounder and more lustrous. 

The B.Mori and Muga imagos cut their way through one end of the cocoon, thus making the filament discontinuous. The Tasar moth secrets an enzyme called cocoonase, which softens the cocoon shell facilitating  emergence. The eri moth spins an open ended cocoon through which the imago can fly to full term. 

In silk only male worm can fly. 

During the process of boiling of silk 75% of the sericin is removed. Care is taken to retain the 25% of the gum to prevent tangling. If the boiling is insufficient, filaments tend to snap during weaving, while excess boiling increases the amount of waste silk. 

The thread drawn from the cocoon is of uneven consistency, being finer at the beginning and the end. In order to provide uniformity in consistency, additionaly filaments are drawn in course of reeling, the process is called throwing. 

Because of the structure of cocoon, the process of reeling also generates a residue of waste fiber. In B. Mori, about 45% of the product is floss. This material is spun. This is called Matka. In the case of muga worm 25 to 50 percent may be spun. With regard to tasar only about 10 per cent of the filament can be reeled

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Properties of Nylon 6,6

Nylon 6,6 is one of the most important synthetic textile fibres. It belongs to the polyamide family and is valued because it combines strength, toughness, elasticity, abrasion resistance and heat resistance in one fibre. In textile language, Nylon 6,6 is not merely a “strong fibre”; it is a fibre that can tolerate repeated bending, rubbing, stretching and recovery better than many conventional textile fibres.

The name Nylon 6,6 comes from the chemical structure of the two raw materials used to make it. Hexamethylene diamine contains six carbon atoms, and adipic acid also contains six carbon atoms. When these two compounds react, they form a long-chain polyamide called Nylon 6,6.

Table of Contents

1. Overview of Nylon 6,6
2. Why Nylon 6,6 Has Good Properties
3. Strength and Elongation
4. Density and Weight
5. Elastic Recovery
6. Moisture Regain
7. Abrasion Resistance
8. Appearance and Lustre
9. Action of Heat
10. Chemical Properties
11. Biological Properties
12. Dyeing Behaviour
13. Advantages and Limitations
14. Uses of Nylon 6,6
15. Nylon 6 and Nylon 6,6 Compared
16. Summary

1. Overview of Nylon 6,6

Nylon 6,6 is a synthetic fibre produced from petrochemical raw materials. It is a thermoplastic fibre, which means that it softens on heating and can melt at high temperature. This behaviour is very different from cotton or wool, which do not melt in the same way.

The most important feature of Nylon 6,6 is its balanced performance. It is strong, but not brittle. It stretches, but it also recovers well. It resists abrasion, but it can still be made into fine filaments for apparel. This is why it is used in products as different as hosiery, carpets, tyre cords, ropes, sewing threads, luggage fabrics and engineering components.

Visual 1: Property map of Nylon 6,6.

2. Why Nylon 6,6 Has Good Properties

The properties of Nylon 6,6 come from its molecular structure. It is a polyamide, which means that its long polymer chain contains repeated amide linkages. These amide groups can form hydrogen bonds between neighbouring polymer chains, giving the fibre strength, toughness and dimensional stability.

A simplified representation of the repeating unit of Nylon 6,6 may be shown as:

\( [-NH-(CH_2)_6-NH-CO-(CH_2)_4-CO-]_n \)

During fibre manufacture, the polymer is melt spun and then drawn. Drawing aligns the molecular chains more strongly in the fibre direction. This molecular orientation is one reason why Nylon 6,6 filaments become stronger after drawing.

Technical note: The fibre properties of Nylon 6,6 are not due only to its chemical composition. They are also influenced by molecular weight, crystallinity, drawing, heat setting, filament fineness and finishing conditions.

3. Strength and Elongation

The most important property of Nylon 6,6 is its high strength. It has good tenacity and can carry considerable load before breaking. It also has good elongation, which means that it can stretch before failure rather than breaking suddenly like a brittle material.

The combination of strength and elongation is extremely useful in textiles. A fibre that is strong but has no extension may fail under sudden shock. A fibre that extends too much but lacks strength may deform easily. Nylon 6,6 offers a practical balance between these two requirements.

Property	Textile Meaning	Practical Importance
High tenacity	Can withstand load before breaking.	Useful in tyre cord, ropes, industrial yarns and sewing threads.
Good elongation	Can stretch before rupture.	Improves shock resistance and performance during use.
Good wet strength	Retains much of its strength when wet.	Useful in nets, ropes, rainwear fabrics and outdoor articles.

4. Density and Weight

Nylon 6,6 has a density of about 1.14 g/cc. In textile terms, this means that it is lighter than cotton and polyester on a density basis, but heavier than polypropylene. This gives Nylon 6,6 a useful balance between lightness and strength.

Fibre	Approximate Density	Interpretation
Polypropylene	About 0.91 g/cc	Very light fibre.
Nylon 6,6	About 1.14 g/cc	Light to moderate density with high strength.
Polyester	About 1.38 g/cc	Heavier than nylon.
Cotton	About 1.54 g/cc	Heavier than nylon on density basis.

This moderate density helps Nylon 6,6 perform well in applications where high strength is needed without making the product excessively heavy.

5. Elastic Recovery

Nylon 6,6 has excellent elastic recovery. When it is stretched within reasonable limits, it tends to return close to its original length after the load is removed. This property is important in hosiery, socks, sportswear and stretch-blend fabrics.

Elastic recovery should not be confused with elongation. Elongation tells us how much the fibre can stretch. Elastic recovery tells us how well the fibre returns after stretching. Nylon 6,6 is useful because it has both good extension and good recovery.

Practical note: Elastic recovery is one reason why nylon fabrics resist bagging and deformation better than many fibres. It helps products retain shape during repeated wearing, bending and stretching.

6. Moisture Regain

Nylon 6,6 has moderate-low moisture regain compared with natural fibres. It absorbs more moisture than polyester and polypropylene, but much less than cotton or wool. This affects comfort, dyeing, dimensional behaviour and electrical properties.

Fibre	Moisture Behaviour	Textile Effect
Cotton	High moisture absorption	Comfortable in hot climates but slower to dry.
Nylon 6,6	Moderate-low moisture absorption	Dries faster than cotton but may feel less absorbent.
Polyester	Low moisture absorption	Quick drying but may need moisture-management finishing.
Polypropylene	Very low moisture absorption	Very hydrophobic and light.

Moisture absorption also influences static build-up. In very dry conditions, nylon fabrics may develop static electricity, which can cause cling or dust attraction. This can be reduced by fibre blending, finishing or antistatic treatments.

7. Abrasion Resistance

Abrasion resistance is one of the most important practical advantages of Nylon 6,6. Abrasion resistance means resistance to damage caused by rubbing. Many textile products do not fail because of one large force; they fail gradually because of repeated rubbing, flexing and surface wear.

This is why Nylon 6,6 is widely used in carpets, socks, luggage fabrics, upholstery, ropes, nets and industrial fabrics. In carpets, for example, the pile yarn must withstand repeated foot traffic. In socks, the fibre must resist rubbing against footwear and skin. In luggage fabrics, it must tolerate repeated handling and surface friction.

Visual 2: Use-property relationship of Nylon 6,6.

8. Appearance and Lustre

Nylon 6,6 filaments may be produced in bright, semi-dull or dull forms. The lustre depends on the filament structure and the use of delustering agents such as titanium dioxide. Bright nylon has higher shine, while dull nylon has a more subdued appearance.

This ability to control lustre is important in textiles. Apparel fabrics may require reduced shine for a softer look, whereas decorative or technical uses may accept or even prefer a brighter filament. Nylon can therefore be engineered visually as well as mechanically.

Type	Appearance	Possible Use
Bright nylon	High lustre	Decorative filaments and selected apparel uses.
Semi-dull nylon	Moderate lustre	General apparel and textile uses.
Dull nylon	Reduced shine	Uses where a less synthetic appearance is preferred.

9. Action of Heat

Nylon 6,6 has a relatively high melting point compared with many thermoplastic fibres. It generally melts around the 250–265°C range, depending on grade and testing conditions. This gives Nylon 6,6 better heat resistance than Nylon 6, although it is still a thermoplastic fibre and must be handled carefully during ironing and finishing.

Because nylon softens and melts under excessive heat, a hot iron can cause glazing, sticking or fusion. Therefore, nylon garments should not be treated like cotton garments during ironing. Lower temperature settings and the use of a pressing cloth are safer.

Visual 3: Heat behaviour of Nylon 6,6.

Heat Setting

Nylon 6,6 can be heat set. Heat setting means applying heat under controlled conditions to stabilise the shape of a fibre, yarn or fabric. This is useful in pleated garments, textured yarns, hosiery and products where dimensional stability is required.

Heat setting works because Nylon 6,6 is thermoplastic. When heat is applied in a controlled manner, the polymer chains can rearrange and then become more stable after cooling. This is why pleats and textured structures can be made more durable in nylon.

10. Chemical Properties

Nylon 6,6 has good resistance to many common chemicals used in normal textile handling. It generally shows good resistance to soaps, detergents, dry-cleaning solvents, sea water and alkalis under ordinary conditions. This gives it durability in washing, wearing and many industrial applications.

However, Nylon 6,6 is not resistant to all chemicals. Strong acids can damage nylon because the polymer chain contains amide linkages. Strong oxidising agents and unsuitable bleaching conditions may also cause fibre degradation.

Chemical Agent	General Effect on Nylon 6,6
Water and sea water	Generally resistant under normal conditions.
Soaps and synthetic detergents	Generally resistant in ordinary washing.
Dry-cleaning solvents	Usually resistant under normal textile care conditions.
Alkalis	Good resistance compared with many fibres.
Strong acids	Can attack and weaken the fibre.
Strong oxidising agents	May cause degradation or loss of strength.

11. Biological Properties

Nylon 6,6 is resistant to mildew, bacteria and moth attack because it does not provide the same nutrient source as protein fibres such as wool. This makes it useful for products that may be stored for long periods or exposed to damp conditions.

This biological resistance does not mean that nylon products can be stored carelessly. Dirt, finishes, natural-fibre blends and humid storage conditions may still encourage microbial growth on the surface. Proper cleaning and dry storage remain important.

12. Dyeing Behaviour

Nylon 6,6 can be dyed, but dyeing requires careful control. Acid dyes are commonly used because nylon contains amide groups that can interact with dye molecules. Disperse dyes and other dye classes may also be used depending on shade, fastness and processing requirement.

Dyeing uniformity depends on fibre structure, heat history, yarn processing and fabric construction. Uneven heat setting or variation in yarn history may cause shade variation. For this reason, nylon dyeing requires good control of pH, temperature, time and levelling conditions.

13. Advantages and Limitations of Nylon 6,6

Advantages	Limitations
High strength and toughness.	Can melt or stick under excessive ironing temperature.
Excellent abrasion resistance.	May develop static in dry conditions.
Good elastic recovery.	Less absorbent than cotton and wool.
Good resilience and wrinkle recovery.	Strong acids can damage the fibre.
Good resistance to mildew and moth attack.	Long exposure to sunlight may reduce strength.

14. Uses of Nylon 6,6

The uses of Nylon 6,6 are directly connected with its properties. Where strength is needed, it is used in industrial yarns. Where abrasion resistance is needed, it is used in carpets and socks. Where elastic recovery is needed, it is used in hosiery and sportswear. Where dimensional stability and toughness are needed, it is used in technical textiles and engineering products.

Property	Typical Use
High strength	Tyre cords, ropes, industrial yarns and sewing threads.
Abrasion resistance	Carpets, socks, luggage fabrics and upholstery.
Elastic recovery	Hosiery, sportswear and stretch fabrics.
Heat setting ability	Pleated fabrics, textured yarns and shape-retaining products.
Chemical and biological resistance	Nets, outdoor articles and industrial fabrics.

15. Nylon 6 and Nylon 6,6 Compared

Nylon 6 and Nylon 6,6 are both polyamide fibres, but they are not the same fibre. Nylon 6 is produced from caprolactam, whereas Nylon 6,6 is produced from hexamethylene diamine and adipic acid. Nylon 6,6 generally has a higher melting point and better dimensional stability, while Nylon 6 is often considered easier to dye.

Point of Difference	Nylon 6	Nylon 6,6
Raw material	Caprolactam	Hexamethylene diamine and adipic acid
Polymerisation route	Ring-opening polymerisation	Condensation polymerisation
Melting point	Lower than Nylon 6,6	Higher than Nylon 6
Dimensional stability	Good	Generally better
Dyeing behaviour	Generally easier to dye	Good, but needs careful control

16. Common Student Mistakes

One common mistake is to think that nylon is strong only in dry condition. Nylon 6,6 retains much of its strength even when wet, which is one reason it is useful in ropes, nets and outdoor applications.

Another mistake is to assume that nylon can be ironed like cotton. Nylon is thermoplastic, so excessive heat may cause sticking, glazing or melting. Cotton may scorch, but nylon can soften and fuse.

A third mistake is to confuse Nylon 6 with Nylon 6,6. Their names look similar, but they are made from different raw materials and have different thermal and dimensional behaviour.

17. Summary

Nylon 6,6 is a strong, elastic and durable synthetic fibre. Its major properties include high strength, good elongation, excellent abrasion resistance, good elastic recovery, moderate-low moisture regain, good chemical resistance and resistance to mildew and moth attack.

Its thermoplastic nature is both an advantage and a limitation. It allows heat setting, pleating and shape stabilisation, but it also means that excessive ironing temperature can damage the fibre. Its high melting point gives it better heat resistance than Nylon 6, but normal textile care still requires caution.

The practical importance of Nylon 6,6 lies in its balance of properties. It is suitable not only for apparel and hosiery but also for carpets, ropes, tyre cords, industrial fabrics, luggage materials and engineering applications. For students and merchandisers, Nylon 6,6 should be understood as a fibre where chemistry, spinning, drawing and heat setting together determine final performance.

Related Reading on Synthetic Fibres and Fibre Properties

• Manufacturing Process of Nylon 6,6
• Properties of Nylon 6
• Manufacturing Process of Nylon 6
• Properties of Polyester
• Determination of Abrasion Resistance of Fabric

Sources Consulted

1. Encyclopaedia Britannica. Nylon. Available at: https://www.britannica.com/science/nylon
2. Encyclopaedia Britannica. Polyamide. Available at: https://www.britannica.com/science/polyamide
3. MatWeb. Nylon 66, Unreinforced. Available at: https://www.matweb.com/search/datasheettext.aspx?matguid=a2e79a3451984d58a8a442c37a226107
4. MatWeb. Nylon 66, Extruded. Available at: https://www.matweb.com/search/DataSheet.aspx?MatGUID=ca447ababd504bc388b2dcb8eda05980
5. Textile Learner. Nylon 66 Fiber: Preparation, Properties and Applications. Available at: https://textilelearner.net/nylon-66-fiber-applications/

General Disclaimer

This article is intended for textile students, merchandisers, teachers and general readers. The values and explanations given here are for educational understanding and may vary with polymer grade, fibre type, filament denier, drawing ratio, heat setting conditions, finishing treatment and testing method. For industrial use, product development or laboratory reporting, always refer to the relevant technical data sheet, testing standard and supplier specification.

Manufacturing Process of Nylon 6,6

Nylon 6,6 is one of the most important synthetic fibres used in textiles and industrial products. It belongs to the polyamide family and is produced by the reaction of two chemicals: hexamethylene diamine and adipic acid.

The name Nylon 6,6 comes from the fact that both the starting chemicals contain six carbon atoms. Hexamethylene diamine contributes six carbon atoms, and adipic acid also contributes six carbon atoms. When these two materials react, they form a long-chain polymer called polyhexamethylene adipamide, commonly known as Nylon 6,6.

Table of Contents

1. Raw Materials Used in Nylon 6,6
2. Chemical Reaction of Nylon 6,6
3. Manufacturing Process Flow
4. Polymerisation of Nylon 6,6
5. Melt Spinning of Nylon 6,6
6. Drawing of Nylon 6,6 Filaments
7. Important Process Control Points
8. Applications of Nylon 6,6
9. Nylon 6 and Nylon 6,6: Basic Difference
10. Frequently Asked Questions

1. Raw Materials Used in Nylon 6,6

The two main raw materials used in the manufacture of Nylon 6,6 are:

Raw Material	Chemical Nature	Role in Nylon 6,6 Formation
Hexamethylene diamine	Diamine compound	Provides amine groups required for amide bond formation.
Adipic acid	Dicarboxylic acid	Provides carboxylic acid groups required for amide bond formation.

For producing high molecular weight Nylon 6,6, the two raw materials must be combined in nearly equal molecular proportion. If one material is present in excess, the polymer chain may terminate early, resulting in lower molecular weight and weaker fibre properties.

2. Chemical Reaction of Nylon 6,6

Nylon 6,6 is formed by condensation polymerisation. In this reaction, the amine group of hexamethylene diamine reacts with the carboxylic acid group of adipic acid. During this reaction, amide linkages are formed and water is eliminated as a by-product.

The simplified reaction may be written as:

\( nH_2N-(CH_2)_6-NH_2 + nHOOC-(CH_2)_4-COOH \rightarrow [-NH-(CH_2)_6-NH-CO-(CH_2)_4-CO-]_n + H_2O \)

The important point is not merely the formula, but the formation of repeated amide linkages. These amide linkages are responsible for many characteristic properties of Nylon 6,6, such as strength, abrasion resistance, resilience and heat resistance.

Technical note: Nylon 6,6 is a polyamide. The word polyamide means a polymer containing many amide linkages in its molecular chain.

3. Manufacturing Process Flow

The manufacturing process of Nylon 6,6 may be understood in the following sequence:

Hexamethylene diamine + Adipic acid → Nylon salt → Polymerisation → Nylon polymer → Chips → Melt spinning → Cooling → Drawing → Winding

In industrial practice, the process is carefully controlled because fibre quality depends not only on the chemistry but also on melting, filtration, extrusion, cooling, drawing and winding conditions.

4. Polymerisation of Nylon 6,6

The first important stage is the preparation of nylon salt. Hexamethylene diamine and adipic acid are mixed in water to form a salt. This salt helps in maintaining the correct balance between the amine and acid groups.

The nylon salt solution is then concentrated by removing water. After this, it is heated under controlled conditions so that polymerisation can take place. As the reaction proceeds, long polymer chains are formed. Water produced during the reaction must be removed so that the reaction can continue in the forward direction.

The molten polymer may then be extruded and cut into chips. These chips are later used for fibre spinning. In some continuous processes, the molten polymer may also be taken directly for spinning.

Practical understanding: Polymerisation creates the fibre-forming material. Spinning converts that material into filaments. Drawing improves the strength and orientation of those filaments.

5. Melt Spinning of Nylon 6,6

Nylon 6,6 is generally spun by the melt spinning process. In melt spinning, the nylon polymer chips are first dried and then melted. The molten polymer is forced through a spinneret, which is a metal plate containing a number of very fine holes.

As the molten nylon comes out of the spinneret, it appears in the form of fine continuous filaments. These filaments are cooled by air and solidify quickly. The number, size and shape of spinneret holes influence the fineness and cross-sectional character of the filaments.

During spinning, the molten polymer should be protected from unnecessary contact with oxygen because oxidation and degradation can affect the quality of the polymer. For this reason, inert conditions such as nitrogen atmosphere may be used in some systems.

6. Drawing of Nylon 6,6 Filaments

The filaments obtained immediately after spinning are not fully strong. Their molecular chains are not yet sufficiently aligned along the fibre axis. Therefore, the filaments are drawn after spinning.

Drawing means stretching the filaments under controlled conditions. During drawing, the molecular chains become more oriented in the direction of the fibre length. This increases tensile strength, improves dimensional stability and gives the filament better textile performance.

In a typical drawing arrangement, the yarn passes through one set of rollers running at a lower speed and then through another set of rollers running at a higher speed. The difference in roller speed stretches the yarn. The draw ratio may vary depending on the required final properties of the fibre.

After drawing, the filament yarn may be wound on a package. Depending on the end use, it may also be twisted, textured or further processed.

7. Important Process Control Points

The quality of Nylon 6,6 fibre depends on several process control points. Some of the most important are given below:

Process Stage	Control Point	Why It Matters
Raw material preparation	Correct ratio of diamine and acid	Helps in forming high molecular weight polymer.
Polymerisation	Removal of water	Drives the condensation reaction forward.
Chip preparation	Drying of chips	Moisture can create defects during melt spinning.
Melt spinning	Temperature and viscosity control	Ensures smooth flow through the spinneret.
Cooling	Uniform quenching	Prevents uneven filament structure.
Drawing	Draw ratio and roller speed	Controls strength, elongation and molecular orientation.
Winding	Package tension	Prevents yarn damage and package defects.

8. Applications of Nylon 6,6

Nylon 6,6 is used in both textile and industrial applications. Its strength, abrasion resistance and resilience make it suitable for demanding end uses.

Area	Examples
Apparel	Hosiery, sportswear, linings and lightweight fabrics.
Home textiles	Carpets and upholstery fabrics.
Industrial textiles	Tyre cords, ropes, conveyor belts, nets and sewing threads.
Engineering uses	Moulded parts, gears, bearings and other components where strength and wear resistance are needed.

9. Nylon 6 and Nylon 6,6: Basic Difference

Nylon 6 and Nylon 6,6 are both polyamide fibres, but they are made from different raw materials. Nylon 6 is made from caprolactam, whereas Nylon 6,6 is made from hexamethylene diamine and adipic acid.

Point of Difference	Nylon 6	Nylon 6,6
Raw material	Caprolactam	Hexamethylene diamine and adipic acid
Polymer type	Polyamide	Polyamide
Manufacturing route	Ring-opening polymerisation	Condensation polymerisation
General character	Good toughness and dyeability	Good strength, heat resistance and dimensional stability

10. Common Student Mistakes

Students often remember only that Nylon 6,6 is made from two chemicals, but the more important understanding is that these two chemicals form amide linkages. These amide linkages make Nylon 6,6 a polyamide.

Another common mistake is to think that spinning alone gives full strength to the fibre. In reality, drawing is essential because it aligns the polymer chains and improves strength.

A third mistake is confusing Nylon 6 with Nylon 6,6. Nylon 6 is produced from one main raw material, while Nylon 6,6 is produced from two main raw materials.

Frequently Asked Questions

1. Why is it called Nylon 6,6?

It is called Nylon 6,6 because both of its main raw materials contain six carbon atoms. Hexamethylene diamine has six carbon atoms and adipic acid also has six carbon atoms.

2. What type of polymerisation is used for Nylon 6,6?

Nylon 6,6 is produced by condensation polymerisation. During this reaction, amide linkages are formed and water is eliminated.

3. Why is drawing necessary after spinning?

Drawing is necessary because freshly spun filaments have lower molecular orientation. When the filament is stretched, the polymer chains become more aligned along the fibre axis, improving strength and usefulness.

4. What is the function of the spinneret?

The spinneret converts molten polymer into fine continuous filaments. It contains small holes through which the molten nylon is extruded.

5. Why is Nylon 6,6 important in textiles?

Nylon 6,6 is important because it has good strength, elasticity, abrasion resistance and resilience. These properties make it useful for apparel, carpets and industrial textile products.

Summary

Nylon 6,6 is manufactured from hexamethylene diamine and adipic acid. These raw materials first form nylon salt, which is then polymerised to produce Nylon 6,6 polymer. The polymer is converted into chips or directly taken for spinning.

In melt spinning, the polymer is melted and extruded through a spinneret to form filaments. These filaments are cooled, drawn and wound. Drawing is a very important stage because it improves molecular orientation and gives the fibre its required strength.

Thus, the manufacturing process of Nylon 6,6 may be understood as a combination of chemistry and fibre formation: polymerisation creates the polymer, melt spinning creates the filament, and drawing develops the final textile properties.

Disclaimer

This article is intended for textile students, merchandisers and general readers. Industrial Nylon 6,6 manufacturing may vary depending on plant design, polymer grade, equipment configuration and end-use requirements. The explanation here simplifies the process for educational understanding.