A modacrylic is a synthetic copolymer. Modacrylics are soft, strong, resilient and dimensionally stable. They can be easily dyed, show good press and shape retention, and are quick to dry. They have outstanding resistance to chemicals and solvents, are not attacked by moths or mildew, and are nonallergenic. Among their uses are in apparel linings, furlike outerwear, paint-roller covers, scatter rugs, carpets, and work clothing and as hair in wigs.
Commercial production of modacrylic fiber began in 1949 by Union Carbide Corporation in the United States. Modacrylic and acrylic fibers are similar in composition and at one time were in the same category. In 1960 the Federal Trade Commission decided to separate the two fibers and establish a category for each.
The Federal Trade Commission defines modacrylic fibers as manufactured fibers in which the fiber-forming substance is any long-chain synthetic polymer composed of less than 85%, but at least 35% weight acrylonitrile units except when the polymer qualifies as rubber.
Production
Modacrylic fibers are modified acrylic fibers made from acrylonitriles, but larger amounts of other polymers are added to make the copolymers.
The modacrylic fibers are produced by polymerizing the components, dissolving the copolymer in acetone, pumping the solution into the column of warm air (dry-spun), and stretching while hot.
Properties
A modacrylic has properties that are similar to an acrylic. However, modacrylics are flame retardant and do not combust. The fibers are difficult to ignite and will self-extinguish. In addition to a modacrylic's flame retardant properties it has a relatively high durability that is comparable to wool. Modacrylic fibers have a moderate resistance to abrasion and a very low tenacity.
One of the most interesting properties of Modacrylic fabrics is the arc flash protection, where it has very good values.
Modacrylics are poor conductors of heat. The fabrics are soft, warm and resilient but are prone to pilling and matting. Modacrylics display high performance when it comes to appearance retention. The fibers are quite resilient and will not wrinkle. They also have great dimensional stability and high elastic recovery, which gives them the ability to hold their shape.