Laserinduced heat-setting of thermoplastic monofilaments

The textile industry applies numerous heat-setting solutions to improve properties of textile materials. To obtain a crimped effect, these techniques take advantage of the thermoplastic properties of the material. The industrial partner required an energy efficient process which produces geometrically determined crimping effects. During the experimental phase it was possible to achieve a very short heat treatment time on moving filaments. A laser beam, rapidly moved along a predetermined path, a fast temperature measurement and a rapid control of laser power enabled the short time heat treatment phase. Filament forming and heat treatment were simultaniously carried out at 8 filaments and at a speed of up to 60 m/min. Within the investigations it was possible to show that specific textile p hysical values like shrinkage, crimp and tensile strength can reproducibly be affected. The objective of this study was to perform a heat-setting process with a newly developed treatment system, wh ich allows creating geometrically determined crimping effects on filaments within a continous process. The technology works with different filament cross sections and types of materials, such as polyethylene, polyurethane and polypropylene. The use of multispot-radiation in comparison with online temperature control offers numerous new areas of applications in processing thermoplastic monofilaments.