1. 1 Part 1: Textile Materials Dr Jimmy Lam Institute of Textiles & Clothing The Hong Kong Polytechnic University

2. 2 Outline Natural fibers for textile –Cotton fibre, wool, silk and flax Man-made fibers for textile –Nylon, Polyester, Acrylic and Spandex Yarn Count Calculation (tax and denier)

3. 3 Textile fibres (Raw Material) A fiber is the smallest part of a fabric. It is an individual, fine, hair-like substance. Fibers have a comparatively high ratio of length to width, thus ensuring the flexibility required for manufacturing and end use (for weaving and knitting). Fibers can be grouped into Nature and Man-made Fibers

4. 4 Nature Fibers Cotton (Vegetable fiber) Wool (Animal fiber) Silk (Animal fiber) Flax (Vegetable fiber)

5. 5 Man-made fiber Nylon (Polyamide) Polyester Acrylic Spandex

6. 6 Cotton Cotton is a plant fiber, composed mainly of cellulose. Cotton is classified by its fiber length, color and cleanliness. The fiber length is the most important since the longer the staple length, the better the fiber properties. Cotton fibre length lies between ½ and 2 ½ inches, most common used is 1 to 1 ¼ inches

7. 7 Cotton Properties The fiber has good strength and abrasion resistance. It is hydrophilic, absorb moisture quickly and dried quickly. Quick drying gives a cooling effect which makes cotton a good fiber for hot weather. The fiber is completely washable and dry- cleanable. There are no static or pilling problems.

8. 8 Cotton Properties and end uses Cotton, however, has little luster and poor elasticity and resiliency. It is attacked by mildew and silverfish. It is weakened by resin chemicals used in finishing. The end uses of cotton include a wide range of products in apparel, furnishings and industrial areas. Examples include blouses, jackets, towels, carpets, curtains, bagging

9. 9 Wool Wool is the fiber that forms the covering of sheep. Wool shorn from live sheep is called fleece wool. Lamb’s wool is wool taken from sheep of less than one year old and is very soft. Wool is mainly composed of protein (likes human hair) because it is animal fiber. It is a medium weight fiber of natural cream with fiber length between 1 and 18 inches..

10. 10 Wool Quality Wool quality depends upon the breed of sheep, climate and health of sheep. The thinner the fiber diameter, the better the properties of wool. Merino wool is considered the best grade of wool. It has the most crimp, best drape, most strength, best resiliency, best elasticity, softest hand, and the most scales on its surface..

11. 11 Wool Properties The fiber has good resiliency when dry but poor when wet. Wool has good drape and elasticity and is hydrophilic (13% moisture regain) and has very little problem with static. Wool makes warm fabrics for two reasons. First, it absorbs moisture slowly and dries slowly, thus having no cooling effect and resulting in wool’s feeling warm when worn. Second, wool fabrics have excellent insulation property because the fibers have a natural crimp which prevents them from packing together so forms dead air spaces (trapped air). The trapped air is the insulating barrier.

12. 12 Wool Properties and uses Wool is a weak fibre and loses about 25% strength when wet. It has poor luster and wool garments usually must be dry-cleaned because the fabric will felt and shrink greatly if washed at elevated temperatures. Felting occurs in the presence of heat, moisture and washing. Wool is vulnerable to moths but can be mothproofed. Pilling will occur with this fiber. The principal end uses of wool include dresses, suits, sweaters, carpets.

13. 13 Man-made fibers

14. 14 Nylon (Polyamide) Nylon is a man-made fiber in which the fiber-forming substance is a long chain polyamide in which less than 85% of the amide linkage are attached directly to two aromatic rings. The fiber has a rod-like shape with a smooth surface

15. 15 Nylon Properties Nylon is a lightweight fiber with excellent strength and abrasion resistance. It is about 10% weaker when wet. It is very good elasticity, good resiliency and good draped and can be washed or dry-cleaned. Nylon, however, is a hydrophobic fiber and absorbs 4 ½ percent moisture regain. Nylon has static and pilling problems and has poor resistance to prolonged and continuous exposure to sunlight (unless modified to improve them).

16. 16 Nylon

17. 17 Nylon End Uses The end uses include a wide range of products in the apparel, interior furnishings and industrial areas Examples: Dress, swimwear, exercise wear, hosiery, shirts, jackets, carpets, tents, fish nets, sleeping bags.

18. 18 Polyester Polyester is a man-made fibre in which the fibre-forming substance is composed of at least 85% by weight of ester aromatic carboxylic acid. The fiber has a rod-like shape with a smooth surface.

19. 19 Polyester

20. 20 Polyester Properties Polyester is a medium weight fiber with very good strength and abrasion resistance. It can be washed and dry-cleaned. The fiber has excellent resiliency and is the best wash-and- wear fiber. Polyester, however, is almost completely hydrophobic (0.4% moisture regain). It is difficult to get water and detergent into fiber to remove stains. Static and pilling are major problems.

21. 21 Acrylic (man-made wool) The first acrylic was developed by DuPont (USA in 1950). It uses in sweaters and blankets and has advantages over wool include being stronger, cheaper and washable. A disadvantage is that it is hydrophobic.

22. 22 Acrylic Properties Acrylic is a lightweight fibre with good drape and wool-like hand. It provides fabrics that are warm and light. It has good resiliency and elasticity and has excellent resistance to sunlight and weathering. It may be washed or dry-cleaned.

23. 23 Acrylic

24. 24 Acrylic Properties and Uses Acrylic, however, has only fair strength and becoming 20% weaker when wet. It is hydrophobic (1 ½ % moisture regain) with static and pilling problem. The end uses are sweaters, dresses, blankets, carpeting, children’s garment.

25. 25 Yarn count calculation What is yarn count? How to determine yarn thickness? Why they are important?

26. 26 Yarn Count Definition Yarn tex is to measure the yarn fineness and is defined as the ratio of weight (g) to its length Tex = weight (g)/ length (m) X 1000

27. 27 Conversion of Tex to other systems Tex =590.5 / Cotton Count Tex = Denier /9 Tex =1000/Matric Count (Nm)

28. 28 Yarn Count Calculation Example: –No of yarn sample taken=12 –Length of each yarn sample=6 cm –Total yarn length=(12x6)÷100 m =0.72m –Weight of these samples =0.060gm –Weight of 1 km in length=(1000 x 0.06)÷0.72 =83.3gm –Therefore, yarn count =83.3 tex –Conversion to other systems: 1.Cotton Count =590.5/83=7 ’ s 2.Denier =83.3 X 9=749 denier 3.Metric Count (Nm)=1000/83.3 =12 Nm

29. 29 Discussion What are the advantages of man- made fiber? Why 100% man-made fiber is not suitable for apparel product?