Abstract: As an environmentally friendly decorative material, wall cloth is well in line with human's aesthetic and environmental protection requirements for its advantages of seamlessness, heat preservation and sound absorption. However, at present, the research and development scope of the foreign wall cloth industry is wide, while the research and development of wall cloth in China started late, with most related studies staying at the decorative level, and few on the functions. Moreover, the domestic research and development of wall cloth focus on single-layer wall cloth, which can not fully meet the requirements of multi-functional wall cloth. Composite wall cloth, usually made of woven fabric and non-woven fabric by hot pressing with binder, is a laminated composite fabric. It can not only maintain the original functional characteristics of each layer of the fabric, but also can be designed to increase other functions, showing the superposition of functions as a whole. The development of multi-functional textile fibers and the research and development of wall cloth preparation technology have promoted the growth of the composite wall cloth market.
To address the lack of functional wall cloth and undiversified types in the domestic market, we mainly focus on the hot-pressing process of preparing composite fabrics for wall cloth in this paper. We  selected the ethylene vinyl acetate (EVA) hot-melt adhesive film with a low melting point, wide bonding range and aging resistance as the adhesive. Firstly, we carried out the thermal analysis. On this basis, with the temperature, pressure and time of the hot-pressing process as the main influencing factors of the test, we designed the L25(53) orthogonal test to study the effect of the hot-pressing process on the bonding structure and properties of  composite fabrics with EVA hot-melt adhesive films. In this paper, we analyzed the cross-section bonding structure of the composite fabric by thickness and cross-section electron microscopy, including the morphological changes of the hot-melt adhesive film, the degree of penetration, the binding effect with yarns and fibers, etc. We also analyzed the reasons for the influence of the hot-pressing process on the properties of composite fabrics from the microstructure. It is found that for composite fabrics with EVA hot-melt adhesive films, pressure has the greatest influence on the thickness and air permeability, and temperature has the greatest influence on the peel strength. At the same time, pressure has a significant effect on the thickness, a highly significant effect on the air permeability, and temperature has a significant effect on the peel strength. With the increase of hot-pressing temperature, pressure and time, the thickness shows a downward trend. With the increase of temperature and time, the permeability and peeling strength increase first and then decrease. With the increase of pressure, the permeability and peeling strength show a downward trend. The optimum parameters for the hot-pressing process are 100 °C, 0.5MPa and 90 s. The hot-melt adhesive of the composite fabric prepared under this condition is closely combined with the yarn and fiber of the two layers of the fabric. The adhesive layer will form gaps and micro-pores. The thickness is 0.65 mm, the air permeability can reach 156.72 mm/s, and the peel strength can reach 32.55 N.
The relationship between the hot-pressing process conditions and the bonding structure and properties of composite fabrics with EVA hot-melt adhesive films  can lay a research foundation for the preparation of composite fabrics. Through the selection and design of raw materials, new functional wall cloth products with such functions as anti-fouling property, moisture permeability and flame resistance are prepared to meet human's high-quality requirements for indoor environmental conditions. The research results can provide a process reference for the preparation of composite fabrics by EVA hot-melt adhesive films, and provide a basis for the preparation of functional composite wall fabrics.

Key words: EVA-based hot-melt adhesive film, composite fabrics, hot-pressing process, peel strength, orthogonal experimental

摘要： 为研究热压工艺对EVA热熔胶膜复合织物黏接结构和性能的影响，对热压工艺参数进行优化，采用L25(53)正交试验，以热压工艺的温度、压强和时间为试验的主要影响因素进行分析，对复合织物的厚度、截面结构、透气性和剥离强度进行表征分析。结果表明：对于EVA热熔胶膜复合织物，压强对其厚度和透气性影响最大，温度对其剥离强度影响最大；同时，压强对其厚度有显著影响，对其透气性有高度显著影响，温度对其剥离强度有显著影响；随着热压温度、压强和时间的增加，其厚度呈现下降趋势，随着温度和时间的增加，其透气性和剥离强度呈现先上升后下降的趋势，随着压强的增加，其透气性和剥离强度呈现下降趋势；最佳热压工艺参数为100 ℃、0.5 MPa、90 s，该条件下热熔胶与两层织物的纱线和纤维结合紧密，胶层会形成间隙和微孔，复合织物厚度为0.65 mm，透气性可达到156.72 mm/s，剥离强度可达到32.55 N。

关键词: EVA热熔胶膜, 复合织物, 热压工艺, 剥离强度, 正交试验