Development and Standardization of Testing Equipment and Methods for Spacer Fabrics

Abstract

Spacer fabrics are three-dimensional textile structures consisting of two textile cover surfaces and a spacer thread. Up to now, spacer fabrics have been tested according to standards for flat textiles or other non-textile materials. However, these standards do not take into account the special requirements for testing spacer fabrics. Some sample holders of the testing devices are not designed for the thickness of the spacer fabrics, so that the tests cannot be carried out. In other tests, the samples can be mounted, but the test results are falsified by the methodology, e.g. strong compression of the sample before testing. Therefore, objective comparisons among spacer fabrics or between spacer fabrics and conventional flat textiles or non-textile materials cannot be made in all areas of application. The focus of this paper is in the developing of testing devices for seven test setups (1. sample preparation, 2. maximum force, 3. thickness, 4. compression, 5. mass per unit area, 6. permeability to air, 7. abrasion resistance). The new testing devices and methods were designed and manufactured using the method of an iterative development process. The following steps were carried out identically for all seven test setups: deficit analysis, development of concepts, construction of test benches, evaluation, transfer into standards. As part of this research work the developed devices where both tested and evaluated by industrial partners as well as later translated into a standard by the German Institute for Standardization (DIN e.V.). As a central result, a first standard for the testing of spacer fabrics was created and published: DIN 60022–1 “Spacer textiles – Terms and definitions, sample preparation” [4]. For testing textiles, it is important that geometrically identical and structurally intact samples are prepared. Therefore, this standard provides measurement tools and methods for the evaluation of sample quality (e.g. roundness of circular samples, maximum offset and shearing of the surfaces). Two further test methods (determination of thickness and air permeability) were developed and are now being transferred to standards. Within the new test standards, the special properties of spacer fabrics are given special consideration. In addition to the test methods developed within this work, further research is necessary. In particular, the tilting stability (linked to the in-plane and out-of-plane shear measurement) as well as the compression behaviour of spacer fabrics are important tests that need to be analysed and further developed. Therefore, further research is planned for six test methods (1. compression hardness, 2. compression set, 3. tilting stability, 4. pressure point distribution, 5. abrasion resistance, 6. maximum force). This work enables standardized testing of spacer fabrics and thus objective comparisons not only between various spacer fabric constructions but also with conventional flat textiles and with non-textile materials.