VISIOMER® – methacrylate monomers for textile applications
Methacrylate monomers for Textile Applications
Recommended VISIOMER® products:
The textile industry is a major consumer of acrylic emulsions for all processing stages. Acrylic monomers, such as VISIOMER® MMA, GMAA and HEMA, have become stable resources. Besides acrylic emulsions, acrylic monomers are used directly for specific special textile applications, e.g. silk grafting.
Silk, like wool, is a protein-based fiber. Under standard climate conditions (65% relative humidity) the water uptake is 11% – it can climb up to 30% without feeling wet. The particular sheen and texture of silk comes from degumming the raw silk prior to dyeing and weaving. Degumming refers to the removal of the silk gum (sericin) that encloses the raw silk threads. Depending on origin (mulberry silk or tussah silk) and on the degree of degumming, weight loss ranges between 2% and 30% of the raw silk weight – at a simultaneous loss of fiber strength in the order of 20%. The weighting process compensates for the weight loss from degumming. In the past, tannins (tannin or gall nut extracts) or minerals, such as metal salt solutions, were mainly used for weighting. Extensive studies have shown that chemical weighting of the silk fiber with VISIOMER® MAAmide (methacrylamide) delivers key benefit, especially for necktie manufacturing. Silk weighting with VISIOMER® MAAmide is a thermally initiated graft polymerization process, starting with an aqueous solution. Generally, the degummed raw silk is stored for two hours at temperatures of 50-70°C, with stirring in various concentrated aqueous methacrylamide solutions and the addition of 0.1% ammonium persulfate. In practice, the ratio of methacrylamide employed is a useful indicator for determining the desired degree of weighting. Weighting and graft yield decrease as graft temperatures rise. The graft (reaction) temperature to be selected is therefore yet another significant parameter for adjusting the degree of weighting. Besides VISIOMER® MAAmide, VISIOMER® HEMA and/or HPMA can be used for silk weighting to modify the properties of the weighted silk.
WATER AND OIL REPELLENT AGENTS
Water and oil-repellent agents come in the form of an acrylic emulsion polymer that can be used for special applications in the textile industry. It provides durable liquid repellency without compromising the natural feel of cotton, for instance. Textile treatments using this type of chemical result in a host of consumer benefits, such as preventing soiling for a longer period, faster drying and protection from rain. These articles can be used for the most diverse applications, including outerwear, upholstery, rugs, carpets, protective clothing, uniforms, table cloths, wallpaper etc. The newest generation of water and oil-repellent agents is based on fluorochemicals. These products are typically manufactured by emulsion polymerization using 30-60% perfluoroalkyl ethyl methacrylates and 30-50% long side-chain methacrylates. Long side-chain methacrylates, such as VISIOMER® C13-MA and VISIOMER® C17.4-MA, improve water resistance while reducing the dosage of the more expensive perfluoroalkyl ethyl methacrylates. The emulsion is then usually diluted to a solid substance concentration of <1.0%. The textile is dipped in the emulsion, squeezed and then dried/cured at a temperature of up to 170°C for 1-2 minutes.