Acrylic fibers made from 100% acrylonitrile (CH2=CHCN).So acrylic fibers are difficult to dye for their compact structure. To overcome this and to improve solubility in solvent so that the polymer may be wet or dry spinning, co-polymers are now used.

Then the acrylonitrile is copolymerized

Now the polymerization of acrylonitrile X, Its co-polymer is carried out using radon initiators.

Its Tg ( Glass transition temperature) is 70 to 80ºC and suitable dyeing temp is 110 to 120ºC. During dyeing it is seen that acrylic fibers does not deformed because it acrylic fiber are extent that it crease and heat set does not used. P^H range should be 5 to 5.5 acidic medium.

Recipe:

Dye ——————— 0.4%

Acetic Acid ———— 1.1%

Sodium Acited——— 0.5%

Temperature ———– 85ºC

Time ——————– 2 hrs

M:L ——————— 1:30

P^H ———————— 5 to 5.5

Chemical Reaction

FSO₃H+D⁺ —————-> FSO_3­­D+H⁺

F= Fiber

Figure : Dyeing Curve

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