The Effect of Microwave Drying on Warp Sizing

Abstract

The purpose of sizing is to improve physical-mechanical parameters of warp threads, thus, decreasing thread breakage rate in weaving [1][2][3][4][5]. Good sizing consists not only of sizing, but also of drying, which has not been fully investigated to date. As size particles are found in the solution, they move over the whole cross-section of the yarn during the drying process. Yarn drying has changed due to the development of sizing machines. The first dryers were mostly convection ovens in which air currents were used for warp drying. Today, contact drying is the most widely used. It was of great interest to perform research into the possible usage of microwave in the warp sizing, with regard to the performance as well as economical reasons. No such paper has been found in the published literature.For the purpose of this study, we used a newly constructed sizing laboratory device presented in Figure 1. Various types of dryers, convection (I), contact (II) and microwave (III), could be applied after the sizing process. The sizing device enabled a continuous control and regulation of the following parameters: sizing velocity, temperature of the sizing agent, tension and inlet moisture of the warp, outlet moisture of the warp, after drying and drying intensity. The dryer should dry the sized warp in a short period of time to the moisture content it had before sizing, or even less than that. The highest energy consumption in sizing is in the drying procedure. Therefore, the research and development of microwave drying of the sized warp could lead to a considerable reduction in energy consumption.The idea of microwave (MW) application for textile finishing processes first originated in the 1970s when cellulose fabrics were treated with Durable Press (DP) finishing agents and cured in the microwave oven. Although these first results were promising, the idea was abandoned until 1995, when Miller patented his Pre-set process without being aware of the earlier patent. Both cases involved garment microwave treatment, but they were abandoned because the efforts to control the process failed. Until now, microwaves have been used for textile finishing in the combined desizing, scouring and bleaching processes, durable press finishing [6, 7], dyeing and drying processes, as well as for eradication of insects from wool textiles. 1 Microwave dielectric heating is based on activation of polar molecules in treated medium (polarization phenomenon). In a microwave electromagnetic field oscillating at 2.5 GHz, which is a preferred frequency for heating applications, the charge changes polarity nearly five billion times per second. Under the influence of a high frequency Abstract The paper describes our research of microwave usage in drying the size pick-up. An analysis of three different drying processes in relation to physical-mechanical properties of sized yarn has been carried out. Under the same sizing conditions, but different drying methods, the following parameters were determined: breaking force, elongation at break, abrasi...

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