Strengthening the use of plastics in domestic vehicle operations
China's GFRTP exploration research began in the late 60s, about 10 years later than the United States. During this period, Nanjing Fiberglass Institute, Shanghai Shengde Plastics Factory and other units began to carry out some exploration and research on GFRTP GF and reinforcement molding process. In the late 1970s, Nanjing Fiberglass Institute, Hunan Plastics Research Institute, and Changsha Fiberglass Plant conducted GF/PP research and development; Nanjing Fiberglass Institute, Shanghai Shengde Plastic Factory, and Changhong Plastics Factory conducted GF/PA research and development; Beijing Chemical Industry The Institute imported a twin-screw extruder from West Germany and began GFRTP research with a roving. In the early 1980s, the Beijing Yanshan Petrochemical Corporation's Xiangyang Chemical Plant introduced the single screw/J0 process production technology from the United States, and began to strengthen PP research and development work with chopped glass fiber precursors. Beijing Research Institute of Chemical Industry and Nanjing Fiberglass Institute carried out research and development of GF/PBT, GF/PET, Nanjing Fiberglass Institute and Liming Chemical Institute of Chemical Industry, and other units carried out research on grinding fiber reinforced PU and RRIM processes. Nanjing Fiberglass Institute also Milled fiber reinforced F4 and PA research work. In the 1990s, GFRTP developed slowly. For example, GFRTP annual production capacity of Changsha Fiberglass Plant reached 2,500 tons. During this period, the annual output was less than 1,000 tons. Due to problems such as application and promotion, Beijing Xiangyang Chemical Plant/J0 Process no longer produces GF/PP. Pellets.
Overall, China's research work is not too late to start, but development is very slow. The annual output of GFRTP in the country is less than 5,000 tons, which is not commensurate with the speed of industrial development in our country. The gap between developed countries and developed countries is very large.
GFRTP fiber strength can be more fully played GFRP is a hard and brittle material, matrix resin and fiber are rigidly combined. In the non-uniaxial stress state, the material damage is controlled by the matrix, and the fiber strength is not fully exerted. In the GFRTP, the matrix resin and the fiber are combined with the toughness, and the strain capacity is strong, and the fiber can effectively absorb the internal cracks of the matrix. Resist stress cracking, fiber strength can be fully exerted.
High utilization rate of raw materials GFRTP scraps and scraps can be recycled and reused. It is a kind of green material 0 that will not cause secondary pollution, and it will add 20% or less of smashed corner scrap. The physical and mechanical properties of the product will not be affected. . In GFRP, the molecular structure of the matrix resin is a three-dimensional network structure, which cannot be melted or reshaped after curing. Therefore, the disposal of corner scraps and scrapped products becomes a problem. At present, GFRP scrap waste and scrap disposal methods are: 1 buried. Take up a lot of land. Incineration. It will produce secondary pollution such as smoke and ash. Crush and separate and extract glass fiber for reuse. High extraction costs. A US company recycles GF from GFRP molding compounds used in automobiles and SMC wastes. Due to the small market demand for recycled GF, high recycling costs, and high GF recovery prices, the company had to stop this recycling operation. Other treatments, such as pyrolysis, heat in an oxygen-free state to crack organic molecules into smaller molecules to produce oil and gas. However, the investment is large and has limitations. It is not suitable for GFRP scraps with high GF content and high filler content. In addition, if the fine grinding method is used to pulverize and finely grind the corner waste to obtain a product as a filler, it is difficult to make a difference because the cost is too high. So far the world has not found a better way to deal with it, so the development of GFRP is restricted by the environmental protection policies of some countries. For the automotive industry, countries set stringent environmental laws, such as the United States: setting the average fuel consumption standards for cars; Germany: set the average automobile fuel consumption rate by 2005 to drop by 25% from 1990; and the European Union plans to have a 2005 vehicle recycling rate for each vehicle. 85%, 95% in 2015. This is also an important reason for the rapid development of GFRTP.
Better technical and economic performance Thermoplastics have ample sources, many varieties and low costs. With the advent of new GFRTP materials and molding methods, some properties of GFRTP such as heat resistance, rigidity, etc. are comparable to GFRTP. For different materials, different molding processes have different economic volumes. For example, the economic volume of the SMC molding process is 100,000 pieces/year; for the steel stamping process, the economic volume is 100,000 pieces/year or more; for the RTM process economy Batch is a few pieces/year.
Under a certain economic volume, GFRTP can be reduced by 30% compared with GFRP. Therefore, many experts predict that GFRTP will catch up and surpass GFRP in fiber composites in the near future. For example, PPG expects that the world market share of GFRTP will exceed FRP around the year 2000.
Introduction to foreign industries Plastics in the world's automotive industry began in commercial production in the 1950s and 1960s, and developed rapidly in the 1970s. In the 1980s, the company began to adopt lightweight high-strength material systems. In the 1990s, it developed from single interior parts to various parts and components. And functional parts. The volume of foreign automotive plastics in the early 1980s was 80 kg/vehicle, 130,140 kg/vehicle in the medium term and 200 kg/vehicle in the 1990s, which already accounted for 20% of the vehicle's weight. Most of the above-mentioned plastics are GFRP except engineering plastics. With GFRTP, the proportion of GFRP is currently greater than GFRTP, but in recent years, the proportion of GFRP has been declining year by year, and the proportion of GFRTP has been increasing rapidly.
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