关键词: 针织呢绒面料, 绒面性质, 单面压缩法, 绒面毛羽高度, 绒面柔软度

Abstract:

Objective The pile face qualities of knitted woollen fabric include pile (hairiness) height, pile face softness and compressing elasticity, they are important components of fabric qualities which determine the luster, texture clarity, pilling resistance, as well as hand and tactile comfort of fabric, etc. The existing test methods related to fabric hairiness can only test the height or quantity of hairiness on fabric surface and are not applicable to testing knitted woollen fabric, and the evaluation of the pile properties currently still basically relies on experience of subjective evaluators. This research aims to investigate the feasibility using single side compression method to measure the characteristics of hairiness on the fabric surface of knitted woollen fabric, and construct indicator system to characterize the pile face properties.

Method The principle of single side compression of fabric sample with set load were given, and the basic requirements of the testing device for achieving single side compression of fabric sample were analyzed. A typical compression-return process curve for knitted woollen fabric sample was shown, and the method was proposed for determining the boundary point between the compressing stage of the hairiness part and the main body of the fabric on the curve. Based on the compressing curve of the sample, indicators were extracted to characterize the single side compressing properties of the fabric, and further indicators were constructed to characterize the pile face properties. Single side compressing tests on selected samples were conducted, the influences of main experimental parameters such as sample tension, compression-return speed, sample pretreatment methods and conditions on the test results were compared. The feasibility of the testing method was investigated by experiments on the same variety of products with different shearing parameters, and the consistency of the test results was discussed by experiments on different varieties of products with the same shearing parameters.

Results Using the intersection point of the fitted straight line of the fabric body compression stage and the horizontal axis (compression displacement) as the dividing point, the compression part curve of the fabric hairiness was segmented from the compression and return curve. The intercept of the fitted straight line on the horizontal axis, as well as parameters constructed based on the compression curve during the hairiness compression stage, such as the compressing work, specific work, and work coefficient, were adopted to characterize the characteristics of the hairiness compression stage. Single side compressing test results of a double-sided weft knitted wool fabric under four pretension conditions, as well as the test results using five compression-return speeds and using four pretreatment conditions while keeping other test conditions unchanged, were given. At the same time, the single side compression test results of the same variety with different shearing process samples and different varieties with the same shearing process samples were also provided.

Conclusion The pile face properties of knitted woollen fabric can be tested and characterized using the single side compression method. The thickness of the pile (height of hairiness) can be characterized by the compression displacement during the hairiness compression stage; the softness of the pile face can be expressed by the compression work, specific work, and work coefficient during the hairiness compression stage; The elasticity of the pile face can be characterized by the change rate of the hairiness height and compression work during the compression and return processes. The pretension and pre-treatment conditions have significant impact on the test results, and the pretension should be selected reasonably based on the sample specifications.

Key words: knitted woollen fabris, pile face property, single side compression method, hairiness height on pile face, pile face softness