3.3 Dyeing Flashcards
Fibre dyeing:
The application of colour to fibres, before yarn construction.
Both natural and manufactured fibres can be dyed while still in a loose fibre state. This is also known as stockdyeing or loose-stockdyeing. The dye can penetrate each individual fibre, resulting in a uniform colour and excellent colourfastness. Fibres that have been dyed different colours can be combined in a yarn to produce heather or tweed effects.
Piece dyeing:
The application of colour to fabric. In the USA, fabric is often referred to as piecegoods and a fabric shop often called a piecegoodsstore. Piecedyeing means to dye in fabric form. This is the easiest and least expensive way of dyeing and also the method most widely used. Fabrics can be left undyed until fashion dictates a particular shade. The dye does not penetrate the fabric as well as in the previous methods, but it is sufficient for most end uses.
Problems can arise when a fabric consists of more than one type of fibre, each reacting differently to a dye. To ensure a final uniform colour it may be necessary to use two or more dyes. The dyes can be applied simultaneously (one-bath process) or separately (two- bath process).
Crossdyeing is achieved if a fabric contains more than one type of fibre, each reacting differently to a dye or mixture of dyes. One fibre may not accept a dye at all and remain white. Depending on how the different fibres have been arranged, the result can be stripes, a plaid, check, tweed or heather effect.
Product dyeing:
The application of colour to a completed garment or other textile article. An article can be dyed after it has been completed. For many years this method was used mainly for dyeing sweaters and household items such as towels and bedspreads. The method used for this is called paddledyeing. These days, product dyeing is used on fully manufactured garments. The fabric is prepared for dyeing, cut and sewn into garments and then left until orders for specific colours arrive. Garments can then quickly be dyed in the correct colour. This is known as garmentdyeing. The colour of garment-dyed clothing is more inclined to bleed or fade than that of clothing that has been dyed conventionally. Benetton garments are frequently garment-dyed.
Solution dyeing:
The application of colour to manufactured fibres by adding the pigment to the spinning solution prior to extrusion.
In solution dyeing, the dye is added to the spinning solution before it is forced through the spinneret. Solution dyeing is also called masspigmentation or dopedyeing. Obviously, it can only be used for manufactured fibres. The resulting colour is extremely even and colourfast. It is practically impossible to remove the colour completely if solution dyeing has been used. It is therefore also not possible to change the colour of solution-dyed fibre if the colour is no longer in fashion.
Yarn dyeing:
The application of colour to yarn before fabric construction.
Yarn can be dyed after spinning. Yarn dyeing is one of the oldest methods used. It is usu- ally less labour-intensive than fibre dyeing. It also allows the use of different coloured yarn in the same fabric, producing plaids, checks or stripes. Knitted fabrics are frequently dyed before the actual knitting process because piece dyeing can damage the knitted fabric. The major disadvantage of yarn dyeing is that fashion colours must be accurately predicted so that the manufacturer is not left with a large stock of fabric in an unfashionable colour, or with too little fabric in a highly popular colour.
