15 November 2012

Dyeing of Glass Fiber

Glass Fiber:
Glass fiber is a material consisting of numerous extremely fine fibers of glass. Fiberglass is a strong and lightweight reinforcement used in composites, communication, data transfer, or decorative purpose. Glass fibers able to transfer light, ray and radiation inside its subtle hole. Although strength properties are somewhat lower than carbon fiber and it is less stiff, the material is typically far less brittle, and the raw materials are much less expensive. 

Glass fiber fabric
Dyeing of Glass Fiber:
Dyeing of glass fiber filaments, fabrics or fabric is not so easy. In this case, it must be taken into consideration that, under normal circumstances, there is no affinity between glass fiber and dye and that no penetration of the dye into the glass fiber is possible, only surface dyeing or coloration is possible.

The following overview includes patented processes of glass fiber dyeing or coloration which must be regarded as being legally protected:
  1. Fused mass coloration or dyeing
  2. Dyeing of activated surfaces of glass fibre
  3. Direct dyeing methods of glass fibre
  4. Pre-mordanting dyeing methods
  5. Bonding-agent dyeing methods
Stated of these process are given below:

1. Fused mass coloration or dyeing: Using coloured metal oxides yielding weak dyes only as the colour intensity inevitably decreases with the cross section of the filament.

2. Dyeing of activated surfaces of glass fiber: Predominantly older processes of relatively little practical importance and usually yielding weak coloration, deficient in crocking fastness and, almost without exception, having a tendency to damage the fibers surface.

3. Direct dyeing methods of glass fiber: Without pre-treatment, using conventional dyeing techniques and, in this case, yielding surface coloration or dyeing which is barely acceptable. Methods involving the deposition of water-insoluble dyes are exceptions to this but usually only weak coloration can be achieved, e.g., when using sulphur or vat dyes.

4. Pre-mordanting dyeing methods: 
a) metal-salt process gives strong colours in some cases but almost always with insufficient crocking fastness, b) cation active process gives very strong colorations which, with the right choice of dye, can have good fastness properties against water and light but only moderate crocking fastness.

5. Bonding-agent dyeing methods: Coating with dyeable or dyed films: 
a) Pigment dyeing methods are the most elegant and simplest to use. Pale to medium shades are possible with maximum light, water and crocking fastness (with the right choice of dye) while the properties of the dark colours (marine and black) are frequently much worse. The principle consists of fixing the pigment using synthetic resins. 
b) Other bonding-agent dyeing methods are to some extent still very inconvenient and unsatisfactory (especially with regard to crocking fastness). Exception: Õ Corona discharge process with good overall fastness but crocking fastness and grease resistance are not completely satisfactory. No dark full shades obtainable. 

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