GPPS(1) slurry method. Polymerization in diluents (such as hexane) is the earliest industrialization and the most productive method so far. (2) liquid phase noumenon method. Polymerization in liquid propylene under the condition of 70 C and 3MPa. (3) gas phase method. Polymerization of propylene under the condition of gaseous state. The latter two methods do not use diluent, the process is short, and the energy consumption is low. Liquid ontology method has shown the advantages of catch up from behind. Molding characteristics (1) physical properties: PP is a non-toxic, tasteless and highly crystalline white polymer. It is one of the lightest varieties of all plastics, and is particularly stable for water. The water absorption of 14h in water is only 0.01%. The molecular weight is about 8~15 million, and its formability is good. However, because of the large shrinkage, the original wall products are easy to sag, the gloss of the product surface is good, and it is easy to color. (2) mechanical properties: PP has high crystallinity and structure, so it has excellent mechanical properties, and its strength, hardness and elasticity are higher than that of high density PE (HDPE). The outstanding feature is bending fatigue resistance (7 * 10^7), opening and closing, bending and bending without damage trace, dry friction coefficient is similar to nylon, but it is not as good as nylon when oil is lubricated. (3) thermal performance: PP has good heat resistance, the melting point is at 164~170 C, and the product can be sterilized at the temperature above 100 degrees C. Under the action of external force, it is not deformed at 150. The embrittlement is -35 C, and the brittleness will occur at lower than -35 C, and the heat resistance is not as good as PE. EMA In recent years, the household electrical appliance industry in China has developed rapidly, with many varieties and large output. In 2003, there were 18 million 500 thousand refrigerators in our country, 42 million air conditioners, 17 million washing machines and 35 million microwave ovens. According to the research consultation report of China's urban family theater market in 2004~2006, it is estimated that the market scale of China's home theater system will reach 6 million 900 thousand in the next 3 years. In addition, a variety of small household appliances also have a huge potential market, which is an excellent business opportunity for the modified PP. Some manufacturers of plastic raw materials in China have developed special materials for washing machines, such as PP 1947 series, K7726 series and so on, and have been welcomed by the manufacturers of washing machines. Therefore, in the next few years, we should strengthen the development of PP special materials for household appliances in order to meet the demand of market change. Plastic pipe In 2003, the total output of plastic pipes in China broke through 1 million 800 thousand T, up 23% from the same period. In the early days, PP pipes were mainly used as agricultural water conveyance pipes. However, due to the early performance of products, there were still some problems (such as poor impact strength and poor aging resistance), and the market could not be opened. With the Shanghai plastic building materials factory the first introduction of foreign advanced technology, the transportation of imported PP-R material production of cold and hot water in the pipe has been recognized by the market, many manufacturers have the construction of PP-R pipe production line, the price from the initial production of 20 thousand ~3 million /t continue to decline, but the share of PP-R pipe material in the plastic pipe market. Is still low. It is reflected that there is a gap between the domestic PP-R materials and the imported materials, and the quality needs to be improved and improved. According to reports, South Korea has developed a new brand of PP-R 112, a high pressure resistant water supply pipe. The pipe produced by this brand can be used for 50 years under the condition of ultra-high pressure of 20 and 11.2MPa. The plastic pipe is one of the application of chemical building materials in China's key products, the Ministry of construction in 2001 had issued "on the strengthening of copolypropylene (PP-R, PP-B) circular pipe production management and application work, asked relevant departments to jointly do a good job from raw materials, processing, quality and material use, installation and other work, to strictly control PP the quality of the pipe materials, in order to do a better job in China PP pipe production, application and promotion work. High permeability material