Acrylic fibers are produced from acrylonitrile, a petrochemical. The acrylonitrile is usually combined with small amounts of other chemicals to improve the ability of the resulting fiber to absorb dyes. Acrylic fibers are modified to give special properties best suited for particular end-uses. They have optimum application in the dyeing, knitting and home-furnishing sectors, thanks to their ability to absorb dyes and their wool-like aesthetics.
Acrylic is the synthetic fibre that comes closest to wool: it is in fact light, heat-insulating, warm, soft. For this reason, acrylic is often spun together with wool. 100% acrylic yarn is currently a highly sought product, especially used for weaving and knitting.
ACRYLIC, SHRINKING & CONTINUOUS BULKING
The continuous shrinkage method involves the retraction of HB (High Bulk) acrylic yarns directly from the cone of a winding or twisting machine, and the formation of a cone after bulking to be dyed or from a paraffined cone, for use in knitting. This process is carried out to give a high bulk to the yarn and make it pleasant to the touch (hand). Due to the high bulkiness, the yarn is also more opaque and consequently has a better knit performance.
The retraction operation is obtained with a hot treatment on the moving thread, free to retract. Savio's automatic winder for continuous shrinkage, bulking and heat setting combines in a single machine the operations of heat treatment and winding.
Compared to the skein cycle, this continuous shrinkage method is shorter for both raw yarns and pre-dyed yarns, and for dyed raw yarns.