Tire cord fabric is a reinforcing material for the car tire frame, which accounts for about 10% to 15% of the total weight of the tire, which has a great impact on the performance and life of the tire. The plies are usually made of multiple layers of dipped cords bonded with rubber, which play a role in enhancing the overall strength of the tire and stabilizing the outer tire. Tire cord has high technical content, and has high requirements for fiber strength, elongation, elastic modulus, adhesion to rubber, fatigue resistance, dimensional stability, heat resistance and impact resistance. Its raw materials include nylon , Polyester, viscose filament, para-aramid and steel wire, etc.

Nylon

Nylon has low modulus, poor creep resistance, and high thermal shrinkage. Its cords are prone to "flat spot" effect, which can cause tire deformation. Therefore, it is not suitable for radial tire carcasses with high rigidity requirements. In order to improve its dimensional stability, DuPont has developed a low linear density nylon 66 profiled fiber called Hyten, which has a rounded rectangular cross section and an aspect ratio of about 3. The Dutch National Mining Company has also developed a nylon 46 cord, which is superior to ordinary nylon in terms of dimensional stability and heat aging resistance. The modified nylon 66 developed by my country's Shenma Group can also meet the requirements of cars and light-duty radial tires. In addition, the use of low-twist nylon cord can also improve its "flat point" problem.

Polyester

High modulus low shrinkage (HMLS) polyester cord, also known as dimensionally stable polyester (DSP) cord, is suitable for the carcass of passenger car radial tires with high rigidity requirements. However, amination will occur at high temperatures and the strength will decrease, so it is not suitable for tire operation. Large tires that generate high heat at times and difficult to dissipate heat. The first generation of HMLS polyester industrial yarn was produced in the 1990s, and its dimensional stability has been continuously improved. At present, its heat shrinkage rate can reach half of that of conventional polyester, and its modulus has increased by 1/4. Its development goal is to obtain more than viscose The filament has lower heat shrinkage and higher modulus.

Polyethylene naphthalate (PEN)

After the molecular structure design, the benzene ring on the polyester molecular chain is replaced by the naphthalene ring, and PEN can be prepared. It is a fiber material synthesized by Allied Signal Company in the United States, and its strength, dimensional stability and temperature resistance are better than polyester. PEN cord can manufacture high-speed, high-performance tires, and has realized commercial production abroad, but there is little domestic research and development. Japan’s Toyobo and Teijin have jointly developed PEN/PET sheath-core composite fibers; Zhejiang Hailide has also cooperated with Teijin for the development of high-performance PEN cord fabrics. ,

Viscose filament

The viscose filament has good thermal stability, and its dimensional stability is much better than that of nylon and polyester. It has less elastic modulus loss at high temperature, and the tire has high handling stability when running at high speed, and it is comfortable to ride. Due to its low strength, more fibers are used, which improves the shear rigidity. However, its wet strength and fatigue resistance are poor, waste liquid is generated during the production process, and the cost is high.

Aramid

The specific strength and specific modulus of para-aramid are nearly 6 times and 3 times that of steel wire, and 2 times and 10 times that of nylon 66. The tires have good resistance to high and low temperature, and the made tires have good steering properties, comfort and longevity. long. The composite cord fabric obtained by mixing aramid and nylon or polyester can improve the problems of poor compression and bending fatigue resistance, difficult adhesion, and high cost. As early as the 1990s, Henan Shenma Industrial Co., Ltd. began to pay attention to aramid materials, and developed aramid/high-strength nylon 66 composite dipped cords that can be used for high-performance tires. Aramid composite cord fabric has a lot of room for development.