The role of the frame material of silicone rubber and the fabric frame material is to withstand the force from the inside and outside of the rubber product, improve the strength of the rubber product, and limit its deformation. It largely determines the use value of rubber products. Therefore, most rubber products, such as tires, hoses, rubber shoes, rubber cloth, etc., need to use skeleton materials as reinforcement materials. The basic requirements of rubber products for skeleton materials: 1. Strength, modulus and resilience should be high 2. Good heat resistance 3. Good fatigue resistance 4. Good dimensional stability 5. Good adhesion to rubber (surface dipping treatment) 6. Low price 7. The relative density is small, which is conducive to light weight. Good corrosion resistance and flame retardancy. 1. Types and properties of commonly used framework materials in the rubber industry 1. Cotton fiber Cotton fiber has low strength, poor heat resistance and fatigue resistance, low elasticity and high heat build-up. 2. Rayon has higher strength, fatigue resistance and heat resistance than cotton fiber, and has a high initial modulus of elasticity and good dimensional stability, but the strength loss is greater after moisture absorption. 3. Polyamide fiber Polyamide fiber is also called nylon, which is divided into nylon-6 and nylon-66. Nylon fiber has high strength, good fatigue resistance, and excellent impact resistance, but it has low elastic modulus, large heat shrinkability, poor dimensional stability, and poor adhesion to rubber. 4. Polyester fiber Polyester fiber is commonly known as polyester. It has high strength, good heat resistance, fatigue resistance and dimensional stability. Due to the high heat generation of fatigue and easy to cause amination, hydrolysis, etc., the strength of the cord is reduced. Adhesion to rubber is also poor. 5. Polyvinyl alcohol fiber Polyvinyl alcohol fiber is also called vinylon or vinylon. Its strength elastic modulus is higher than cotton fiber, but not as good as nylon. Adhesion to rubber is worse than cotton fiber, but better than nylon and polyester fiber, and it has good chemical resistance, but it has poor heat and humidity resistance. 6. Glass fiber Glass fiber has high strength, excellent heat resistance and corrosion resistance, and good electrical insulation and heat insulation properties, but it has poor fatigue resistance and adhesion to rubber. 7. Steel wire Steel wire is one of the important skeleton materials of rubber products, and its position in rubber fibers is increasing day by day. It is not only an indispensable material for the manufacture of tire travellers, but also a large number of steel cords with the development of radial tires. In addition, it is also widely used in other rubber products such as steel wire braiding and winding hoses. The advantage of steel wire is that it has excellent heat resistance and thermal conductivity. The initial elastic modulus is high. However, it has a high specific gravity, poor fatigue resistance, adhesion to rubber, and chemical resistance. The performance comparison between several commonly used fibers is as follows: strength vinylon>nylon-6>polyester>rayon>--cotton fiber (under dry conditions) vinylon>polyester>nylon—6>cotton fiber>rayon (wet conditions) Bottom) Heat resistance polyester>vinylon>nylon-6>rayon>cotton fiber hygroscopic rayon>cotton>vinylon>nylon-6>polyester elongation nylon-6>polyester>rayon>vinylon>cotton Fiber 8. High-modulus aromatic polyamide fiber is a kind of new star fiber with excellent comprehensive performance developed by DuPont in the United States in the early 1960s and successfully developed in the early 1970s. Originally called B fiber, it was later changed to Kevlar, and it is now called aramid in China. B fiber has the advantages of both synthetic fiber and steel wire, and is called "synthetic steel wire". Its strength is 5 times that of steel wire, its elongation rate is very small, only 3.7~4.2%, and it hardly shrinks (shrinkage rate is only 0~0.2). It has excellent fatigue resistance, small specific gravity, and good chemical resistance. It is the most economical substitute for steel cord. It is suitable for the blocked isocyanate/epoxy resin of polyester cord fabric, and the phenolic butadiene latex dipping system is also suitable for B fiber.