Polypropylene is a thermoplastic resin, is one of the five universal resins. It has the advantages of easy processing, impact strength, deflection resistance and good electrical insulation due to its regular crystal structure. It is widely used in automobile industry, household appliances, electronics, packaging and building materials and furniture.
The structural characteristics of PP determine its characteristics: usually translucent colorless solid, odorless and non-toxic. Because the structure is neat and highly crystallized, so the melting point is up to 167℃, heat resistant and products can be sterilized by steam. Density 0.90g/cm3, is the lightest general purpose plastic. Corrosion resistance, tensile strength 30MPa, strength, rigidity and transparency are better than polyethylene.
The disadvantages of polypropylene are poor impact resistance at low temperature and easy aging, which can be overcome by modification and addition of antioxidant. In the past ten years, China's polypropylene consumption has grown at an average annual rate of 10%, far exceeding the world's average growth level, and it is the second largest consumption of synthetic resin in China. The strong market demand also led to the rapid growth of production capacity and output of polypropylene, which ranked third in the output of the five universal plastics after polyethylene and polyvinyl chloride.
Polypropylene can be classified into various categories, according to the spatial position of methyl (-CH3) in polypropylene molecules into isotactic, isotactic and atactic categories. According to the polymerization process can be divided into mud method, body method, solution method and gas phase method. It can be divided into flat silk (narrow band), fiber, film, extrusion, blow molding, injection molding and so on. According to monomer type, it can be divided into homopolymer polypropylene and copolymer polypropylene.
Application
1.Woven products (plastic woven bags, tarpaulin and rope, etc.) consumption of PP resin in China has been a high proportion of China's polypropylene consumption is the largest market, mainly used for food, fertilizer and cement packaging.
2.Injection molding products are mainly used in small household appliances, daily necessities, toys, washing machines, cars and turnover boxes.
3.Polypropylene film mainly includes BOPP, CPP, ordinary packaging film and microporous film, etc. BOPP has many excellent characteristics such as light weight, high mechanical strength, non-toxic, transparent, moisture-proof, etc. It is widely used in packaging, electricians, electronic appliances, tape, label film, film, composite and many other fields, among which the largest amount of packaging industry.
4.Polypropylene fiber (pp) is a kind of fiber products made of polypropylene as raw material by melting spinning. As polypropylene fiber has many excellent properties, it is increasingly widely used in decoration, industry and clothing, and has become the second largest variety of synthetic fiber.
5.Polypropylene pipe has the characteristics of high temperature resistance, convenient pipe connection (hot melt connection, electric melt connection, pipe fittings connection), recyclable and so on. It is mainly used in water system, heating system, farmland water delivery system, and chemical pipeline system.