By the end of this session you will be able to answer the following exam question. Fibre blends are used extensively for fashion and furnishing fabrics. (a) Giving examples, explain the reasons why fibres are blended. (10 marks) (b) (i) Describe the properties of wool and nylon and explain why they are often blended together. (10 marks) (ii) Give, with reasons, two applications for a wool/nylon blend fabric. (2 x 4 marks)
What is Blending of fibres? Two or more different types of fibres are spun together into a yarn so that the qualities of one can improve the other. This is called Blending. Nylon and Wool socks can be blended to improve strength. Men’s pure wool socks are likely to wear holes as the heel rubs against the shoe in wear, but nylon resists rubbing and so blended wool and nylon socks last far longer. (Wool also gives softness, warmth and absorbs sweat; Nylon gives the strength)
Blending Union Fibre Mixtures and Combinations What are Fibre Mixtures and Combinations? Fibres or yarns are mixed together to create fabrics with a range of different properties. How do you create a ‘mixed’ fabric? There are 2 different ways to create a ‘mixed’ fabric: Blending Union
What is an example of a ‘mixed’ fabric? An example of this is the Cotton/Polyester school shirt. If a school shirt were made of 100% Cotton Fabric it would have a number of very negative properties. It would crease very easily (making the student look very scruffy and uncared for) It would absorb water readily therefore take a long time to dry It would take a long time to iron due to its lack of resilience It would absorb any dye, paint or chemicals used in lessons and any dirt such as grass stains from the playground or food and drink split during the working day. If a school shirt were made of 100% Polyester Fabric it would have a number of very negative properties. The lack of absorbency would leave all perspiration on the skin making the student feel very clammy and uncomfortable. It would melt on to the skin if an accident should happen with a Bunsen burner However if the 2 fibres were combined the school shirt would gain ALL of the positive qualities
Other reasons for blending fibres? What other reasons are there for fibre blending? A crimped appearance can be given when the fabric is finished if a mixture of acrylic staple fibres is spun together. (Some of these shrink easily at this stage in production and others don’t) In the hot finishing process those fibres capable of shrinking doing so, causing the yarn of the fabric made to crimp. This gives it warmth, bulk and texture. All fibres do not take dye equally, so when 2 fibres are spun together and then dyed an interesting effect is produced. This is known as cross dyeing. Man-made fabrics can be heat set. As natural fibres do not hold a crease easily mixing a natural fibre such as Wool with a synthetic fibre such as Polyester a sharper crease can be achieved.
Products made from blended fibres Mohair/Wool/Nylon long cardigan Wool/Nylon/Cashmere Coat Wool/Nylon hoodie The percentage of Nylon in these products is up to 20%
Laminated and coated fabrics A laminated fabric is made up of two or more layers. The layers are held together with an adhesive or thermoplastic fibres which are heat set to fix the layers together. Typical laminated fabrics include Gore-Tex and Sympatex, lace fabrics backed by a woven fabric to give them stability. A coated fabric has a layer of polymer film to the surface of the base fabric. Typical fabrics include PVC coated cottons, and imitation leather fabrics.
Coated fabrics Types of coating Traditional coating layers are made from resin and silicon. Linseed oil and wax are traditional coating materials for heavy cotton that can be reapplied. Rubber and PVC are waterproof but not breathable. Reflective coatings can be made from microscopic glass beads, up to 50,000 per square inch.
By the end of this session you will be able to answer the following exam question. Fibre blends are used extensively for fashion and furnishing fabrics. (a) Giving examples, explain the reasons why fibres are blended. (10 marks) (b) (i) Describe the properties of wool and nylon and explain why they are often blended together. (10 marks) (ii) Give, with reasons, two applications for a wool/nylon blend fabric. (2 x 4 marks)
Homework: Further research Go through your wardrobe or a clothing catalogue and sketch/cut out 5 items. List the fabric properties for each item. What is the most popular mix? Does the popularity change seasonally?