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Fibres,yarns and fabric.
Transcript of Fibres,yarns and fabric.
Often, yarns will be made from more than one kind of fibre, for example, polyester/cotton of wool/acrylic. The purpose of this is to maximise on the properties of each fibre - more of that later! Woven Non-woven Aertex
Worsted Woven fabrics are made by weaving yarns together, vertical yarns for the warp and horizontal yarns form the weft (remember from WEFT to right!) Weaving takes place on a loom - these can be small and hand operated, or large and mechanised. Plain weave Twill weave Satin weave By adding in different yarns and using different methods of weaving we can created many woven patterns. Pile weave eg. denim eg. cotton lawn eg. duchess satin eg. velvet Here are just some examples of woven fabrics, there are many many more. Research a few for you exam so that you can talk about them. From Habotai silk (used for lining) to Hessian (used to make sacks). fabrics can be woven for different uses, different weights and strengths. Habotai Hessian Woven fabrics do not fray until cut - they always have a selvedge at the side which prevent fraying. If you cut a woven fabric parallel to the grain it will be strong and stable. If you cut it on the bias (at 45 degress) the fabrics will drape very well and stretch around a form. Knitted We can also knit fabrics on different scales. By hand with needles or with huge industrial machines. Both of these methods involve the interlinking of loops from one or more continuous yarns. We can create simple knitted fabrics or we can interlink the loops in more complex patterns to give different effects to the fabric. There are two catergories of knitted fabric which you will need to know for your exam: WEFT and WARP. WEFT WARP An example of a weft knit is single jersey. The yarn is knitted from left to right. Weft knits are warm and highly elastic - we can stretch them becasue of the loops. We can clearly see the V's formed on the right side of a weft knitted fabric. Two problems we have with weft knits can be: They loose their shape easily and they unravel. Warp knitted fabrics are constructed up and down the length of the fabric. This is a much more complicated method which CANNOT BE DONE BY HAND. We can create a number of interesting knitted fabrics such as sweatshirt jersey, lace and high performance sportswear knits. Warp knitting machines are very complex and expensive for companies to buy and use. The properties of a warp knitted fabric are: very fast to construct, fabric keeps its shape but stretches less than weft knits, Less likely to unravel, expensive to produce. The main properties of knitted fabrics are stretch, comfort and warmth. The properties of woven fabrics depend on the weight and method of weaving. But most woven fabrics are strong and stable. There are two main methods of created a non woven fabric: Felting and Bonding. Non woven fabrics are made directly from fibres - we skip the yarn stage all together. Fibres are tangled together in a web to form a fabric. Felting is when we apply heat, pressure and moisture to tangle fibres together. We can make felts from natural fibres like wool which are scaly and curly or from synthetic fibres that we can manipulate with heat such as polyester. felted fabrics are dense and very stable, they cannot be stretched at all and as therefore not used to clothing. However, you could use a fleted fabrics structure to make a bag... The other method of creating non-woven fabrics is bonding. This means that fibres are melted or glued together. They can be made by spraying wet or dry fabrics onto a surface and heating them (synthetic) or gluing them with a solvent so that the BOND. Bonded fabric uses include safety and hygiene products, interfacing and linings cleaning materials. Examples of knitted fabrics:
Four-way stretch knits
Two-way stretch knits
Examples of non wovens that you need to know are: wool felt anf interfacing/lining. Properties of non wovens:
not very strong
do not fray
can be moulded into shapes
can be made from recycled fibres
can be made soluable
Can be made to soften with heat (eg hem tape)
weaker when wet
cheap to produce
Can be given special properties such as permeability (water can pass thorugh) because we can amnipulate how the fabric is formed
We can also use micro encapsulation technology to capture chemicals in the fabrics structure such as antisepctic in wipes.