English name: Polypropylene
Abbreviation: PP,
A thermoplastic resin obtained by the polymerization of propylene. There are three configurations of isotactic, random and syndiotactic, and industrial products are mainly composed of isotactic. Polypropylene also includes copolymers of propylene with small amounts of ethylene. Usually translucent colorless solid, odorless and nontoxic. Due to the regular structure and high crystallization, the melting point is as high as 167 degree C, heat resistance, and the products can be sterilized by steam, which are its outstanding advantages. With a density of 0.90g/cm3, it is the lightest general-purpose plastic. Corrosion resistance, tensile strength 30MPa, strength, rigidity and transparency are better than polyethylene. The disadvantage is that it has poor low temperature impact resistance and is easy to age, but it can be overcome by modification and addition of antioxidants.
Features:
Non-toxic, odorless, low density, strength, stiffness, hardness and heat resistance are better than low pressure polyethylene, can be used at about 100 degrees. It has good electrical properties and high frequency insulation not affected by humidity, but becomes brittle at low temperature , Not wear-resistant, easy to age. Suitable for making general mechanical parts, corrosion-resistant parts and insulating parts. Common acid and alkali organic solvents have little effect on it and can be used for tableware.
production method:
①Slurry method. Polymerization in a diluent such as hexane is the earliest industrialized and by far the most productive method. ② liquid phase bulk method. Polymerization was carried out in liquid propylene at 70 degree and 3MPa. ③ gas phase method. The polymerization is carried out under the condition that the propylene is in the gaseous state. The latter two methods do not use diluent, the process is short, and the energy consumption is low. Liquid bulk methods have now shown the advantage of coming later.
Molding characteristics:
1. Crystalline material, low hygroscopicity, easy to melt and rupture, and easy to decompose after long-term contact with hot metal.
2. The fluidity is good, but the shrinkage range and shrinkage value are large, and shrinkage holes, dents, and deformations are prone to occur.
3. The cooling speed is fast, the pouring system and cooling system should dissipate heat slowly, and pay attention to controlling the molding temperature. It is easy to orientate when the material temperature is low and high pressure. When the mold temperature is lower than 50 degrees, the plastic parts are not smooth, and it is easy to produce poor welding and flow marks. Warp deformation is easy to occur above 90 degrees
4. The thickness of the plastic wall must be uniform to avoid lack of glue and sharp corners to prevent stress concentration.
use
Biaxially oriented polypropylene film
Packaging materials occupy an extremely important position in plastic products. According to statistics, the world's plastics used in packaging account for about 35 percent of the total plastic consumption. my country's packaging plastics have developed rapidly, and the output has rapidly increased from 190,000 tons in 1980 to 4.65 million tons in 2003. It is expected to exceed 5.5 million tons in 2005, 7 million tons in 2010, and 9 million tons in 2015, accounting for about 5.5 million tons in 2010. More than 13 percent of the country's total packaging output.
From the product point of view, packaging films account for more than 50 percent of the total packaging plastics. my country's biaxially oriented polypropylene (BOPP) film is one of the areas with the largest consumption of PP resin. In 2003, there were 86 BOPP production enterprises (123 production lines) in my country, with a total production capacity of about 1.4 million t/a. In 2004, it reached 200. 10,000 t/a (138 production lines), and the output will exceed 1 million t. In recent years, domestic enterprises have paid attention to improving the competitiveness of their products, and have successively introduced a number of advanced BOPP production equipment, which can produce films with a width of up to 8.3m and a line speed of up to 400500m/min. For example, Zhejiang Dadongnan Group introduced German Bruckner 6 10,000 t/a production line; Guofeng Group invested 200 million yuan to introduce a 35,000 t/a production line (currently the first in Asia and the fourth in the world with 10m wide BOPP equipment); Changzhou Wujin Jinshi Group introduced 20,000 t/a in Germany Five-layer co-extrusion high-strength and ultra-thin BOPP production line; Fujian Hyundai Group introduced a 25,000 t/a production line; Baoshuo Group plans to introduce a 100,000 t/a production line. According to my country's existing BOPP film production capacity, the annual demand for PP resin is nearly 2 million t. Therefore, attention should be paid to the development of PP special materials with high line speed, elongation and transparency for BOPP films, including supporting PP materials. , propylene copolymer to adapt to the newly introduced BOPP film equipment.
Modified polypropylene for automobiles
In 2003, my country's automobile production was more than 4.4 million units, ranking fourth in the world, with a year-on-year increase of 36.6 percent . According to the US ESM WerWide report: "In 2008, China's automobile production will exceed 6 million vehicles, and in 2015, it will surpass Japan and become the second largest in the world".
The development of the automobile industry is inseparable from the process of automobile plasticization. At present, the self-sufficiency rate of engineering plastics in my country is less than 16 percent . According to the forecast of China Engineering Plastics Association, the demand growth rate of engineering plastics in my country in 2005 was 15 percent , and in 2010, it was about 10 percent , and the demand will increase from 440,000 tons in 2000 to 1.4 million tons in 2010. The demand for engineering plastics in my country's automobile manufacturing industry is growing rapidly, and the total consumption will reach 940,000 tons by 2010 (calculated by the amount of plastics accounting for 5 percent to 10 percent of the weight of the vehicle).
PP has strong competitiveness in the automotive industry, but because of its low modulus and heat resistance, and poor impact strength, it cannot be directly used as auto parts. The modified PP products used in cars are resistant to The thermal performance can be increased from 80 degree to 145 degree 150 degree , and it can withstand high temperature for 7501000h without aging and cracking. According to reports, a new generation of polypropylene HEHCPP products with high orientation crystallinity launched by Toyota Corporation of Japan can be used as automobile dashboards and bumpers, which can reduce the cost by 30 percent compared with similar products produced with TPO as raw materials. Modified PP is used for automobiles. Accessories have very broad development prospects.
Polypropylene for Household Appliances
In recent years, my country's household appliance industry has developed rapidly, with many varieties and large output. In 2003, my country produced 18.5 million refrigerators, 42 million air conditioners, 17 million washing machines, and 35 million microwave ovens. According to the "2004-2006 China Urban Home Theater Market Research and Consultation Report", it is expected that my country's home theater system market will reach 6.9 million units in the next three years. In addition, various small household appliances also have a huge potential market, which is an excellent business opportunity for modified PP. At present, some plastic raw material manufacturers in my country have developed special materials for washing machines, such as PP 1947 series, K7726 series, etc., which are welcomed by washing machine manufacturers. Therefore, in the next few years, the development of PP special materials for household appliances should be increased to meet the changing needs of the market.
Polypropylene for pipes.
In 2003, the national total output of plastic pipes exceeded 1.8 million tons, a year-on-year increase of 23 percent . In the early days, PP pipes were mainly used as agricultural water pipes, but the market failed to open due to some problems in the performance of the early products (impact strength and poor aging resistance). With the introduction of foreign advanced technology by Shanghai Plastic Building Materials Factory, the pipes for conveying cold and hot water produced by imported PP-R materials have been recognized by the market. At present, many manufacturers have built PP-R pipe production lines, and the price is also increased by The 20,000-30,000 yuan/t price in the initial stage of production has continued to fall, but the market share of PP-R pipes in the plastic pipe market is still very low. According to reports, there is still a certain gap between domestic PP-R materials and imported materials, and the quality needs to be improved and improved. According to reports, South Korea has developed a new grade of random copolymer polypropylene PP-R 112 for high-pressure water supply pipes. The pipes produced by this grade can be used for 50 years under the ultra-high pressure state of 20 degree C and 11.2 MPa.
Plastic pipes are one of the key products for the promotion and application of chemical building materials in my country. The Ministry of Construction issued a "Notice on Strengthening the Production Management and Promotion and Application of Copolymerized Polypropylene (PP-R, PP-B) Pipes" in 2001, requiring relevant departments Work together to do a good job from raw materials, processing, quality to pipe use and installation, and strictly control the quality of PP pipes, so as to better do a good job in the production, application and promotion of PP pipes in my country.
Highly transparent polypropylene
With the continuous improvement of people's living standards, it will inevitably bring about different requirements and improvements in various aspects such as culture, entertainment, food, medical care, materials, and room decoration. Many items in the market are increasingly using transparent materials. Therefore, the development of transparent PP special materials is a good development trend, especially the PP special materials with high transparency, good fluidity and fast forming are required in order to be designed and processed into popular PP products. Transparent PP is more characteristic than ordinary PP, PVC, PET, PS, and has more advantages and development prospects.
In recent years, the foreign transparent PP market has grown rapidly. For example, South Korea's LG introduced transparent PP to the market as a substitute for PET; some German companies replaced PVC with transparent PP; the growth rate of transparent PP products in the United States was 7 percent higher than that of ordinary PP products. 9 percent ; In recent years, the annual consumption of PP nucleating transparent agent in Japan is about 2000t. If the addition amount is 0.25 percent , the annual output of transparent PP material in Japan can reach more than 800,000t. According to the introduction of Japan Physical and Chemical Co., Ltd., Japan's transparent PP special materials are used in microwave cookers and furniture with the largest consumption. It is estimated that the demand for transparent PP special materials in foreign markets in 2005 is about 5 million to 5.5 million tons. At present, there is a big gap between domestic transparent PP special materials and foreign countries, and the production and application of transparent PP resin and its products still need to be strengthened.
Polyethylene PVC Polystyrene Polypropylene What is the difference Polyethylene PE
When unpigmented, it is milky white, translucent and waxy; the product feels smooth when touched by hand, flexible and flexible; it can stretch slightly. Generally, low-density polyethylene is softer and has better transparency; high-density polyethylene is harder.
Common products: handbags, water pipes, oil drums, beverage bottles (calcium milk bottles), daily necessities, etc.
Polypropylene PP
White translucent, waxy when unpigmented; lighter than polyethylene. The transparency is also better than that of polyethylene, and it is harder than polyethylene.
Common products: basins, barrels, furniture, films, woven bags, bottle caps, car bumpers, etc.
polystyrene PS
Transparent when unpigmented. When the product is dropped or tapped, it has a metal-like crisp sound, good luster and transparency, similar to glass, brittle and easy to break, and the surface of the product can be scratched with fingernails. Modified polystyrene is opaque.
Common products: stationery, cups, food containers, home appliance shells, electrical accessories, etc.
Polyvinyl chloride PVC
The natural color is light yellow, translucent and shiny. The transparency is better than that of polyethylene and polystyrene, but worse than that of polystyrene. Depending on the dosage of additives, it can be divided into soft and hard polyvinyl chloride. Soft products are flexible and flexible, and feel sticky. The hardness of hard products is higher than that of low-density polyethylene. , while lower than polypropylene, whitening occurs at the inflection point.
Common products: plates, pipes, soles, toys, doors and windows, wire sheaths, stationery, etc.
polyethylene terephthalate PET
The transparency is very good, the strength and toughness are better than that of polystyrene and polyvinyl chloride, and it is not easy to break.
Common products: often bottle products such as cola, mineral water bottles, etc.
