On The Flexible Materials For Car Seats

The subject of this study is on the main properties of the flexible materials for car seats. There are three categories of flexible materials: textiles, synthetic leather and natural leather. The study is divided into following three parts:1. The correlation between the basic properties of seat cover fabrics and their durabilityThe basic properties of seat cover fabrics include: weight, breaking strength, elongation, sewing strength, piling resistance, surface roughness and the floating length of weave structure. The durability is an integrated performance of all the above basic properties. It is an important indicator while evaluating the car seat’s quality. The study involves data collection and statistical analysis. Because of the different types of the variables, the statistical analysis is classified as the "quantitative variables to qualitative variable" analysis and the "qualitative variables to qualitative variable" analysis. For the former, the method of the "principal component analysis" (PCA) was applied to compress the data base, in order to visualize the relationship among the variables. Project the results of the accelerated endurance test into a new 3D space. Conclusions were obtained according to the clustering of the points. However, with the help of the PCA, no significant models were obtained to show the correlations between the variables. For the latter, the analysis of the probability and the "chi-square test" were used to analyze the correlation between the piling resistance, the surface roughness, the floating length of weave structure and the durability of car seats. The results of "chi-square test" show that the correlation exists between the surface roughness and the durability of car seats. However, it denies the relationship between the pilling resistance, the floating length of weave structure and the durability of car seats. Given that the existing assessment methods are still limited to the subjective assessments, thus there could be errors which, to some extent, interfere with or even mislead the results of the statistical analysis. In order to ensure the quality of the statistical analysis, it is necessary to re-examine and to improve the assessment methods, as well as to collect the data in a larger scale.2. The thermal comfort of the flexible materials for car seatsHere, the thermal comfort refers to the instantaneous thermal comfort while the human body contacts with the car seat. It mainly depends on the surface temperature of car seats. After an exposure to sunlight during a certain time, the surface temperature of car seats will rise up to some extent, which mainly depends on the thermal performances of the surface materials. The aim of the study concerns the relationship between the material’s reflectivity and surface temperature. Reflectivity test and the surface temperature test were conducted with the help of the professional test equipments. The results show that a linear correlation (negative correlation) exists between the reflectivity and the surface temperature. In addition, some special treatment to the natural leather’s surface will greatly reduce the surface temperature, thus help to improve the thermal comfort. For textiles, due to the complexity of its inner structure, there was a big difference of surface temperature among the samples. Therefore, it is necessary to conduct a further study on the textiles’ inner structure in order to find out the factors influencing the surface temperature. 3. Improvement of the abrasion resistance test method for PU synthetic leatherAs the current test method MIE is time consuming and following a rather simple "go-back" way of friction, the Martindale method is proposed to replace MIE method. Tests were conducted to compare the abrasion results of PU synthetic leather between MIE and Martindale methods. The results show that Martindale method is not only more efficient but more accurate to some extent than MIE method. During the first 400 rounds of Martindale test, a significant increase in the glossiness has been observed in PU samples’ surface. As a result, 400 rounds could be used as a brief evaluation for the abrasion resistance of the samples. When the number of testing rounds reached 1,600 rounds, the glossiness of the samples’ surface became rather stable. Thus, 1,600 rounds could be chosen as the testing condition to get a final result. In addition, the study shows that the abradant fabric in Martindale test would influence the testing results.