Who knows how the plastic wrapping paper outside the cigarette case is produced?

A plastic called polypropylene. English name: polypropylene.

Molecular formula: [C3H6]n

CAS login number: 9003-07-0

Abbreviation: PP,

A thermoplastic resin is polymerized from propylene. There are three configurations: isotactic, random and syndiotactic. Isotactic is the main component of industrial products. Polypropylene also includes a copolymer of propylene and a small amount of ethylene. Usually a translucent colorless solid, tasteless and nontoxic. Due to regular structure, high crystallinity, high melting point of 167℃, heat resistance, the product can be steam sterilized. With a density of 0.90g/cm3, it is the lightest general plastic. Corrosion resistance, tensile strength of 30MPa, strength, rigidity and transparency are better than polyethylene. The disadvantages are poor impact resistance at low temperature and easy aging, but they can be overcome by modifying and adding antioxidants respectively.

Features:

Non-toxic, tasteless, low density, better strength, rigidity, hardness and heat resistance than low-pressure polyethylene, and can be used at about 100 degree. Good electrical performance, high-frequency insulation, not affected by humidity, but fragile, not wear-resistant, easy to age at low temperature. Suitable for making general mechanical parts, corrosion-resistant parts and insulating parts. Common acid-base organic solvents have little effect on it and can be used for tableware.

Production method:

① Mud method. Polymerization in diluent (such as hexane) is the earliest industrial method and the most productive method so far. ② Liquid-phase bulk method. Polymerization was carried out in liquid propylene at 70℃ and 3MPa. ③ Gas phase method. Polymerization is carried out under the condition that propylene is gaseous. The latter two methods do not use diluent, which is short in process and low in energy consumption. The liquid-phase bulk method has now shown the advantage of coming from behind.

Molding characteristics:

1. Crystalline substance, low hygroscopicity, easy to melt, fracture and decompose when in contact with molten iron for a long time.

2. The fluidity is good, but the shrinkage range and shrinkage value are large, which is prone to shrinkage cavity, dent and deformation.

3. The cooling speed is fast. The cooling of gating system and cooling system should be slow, and the molding temperature should be controlled. The material temperature is easy to orient at low temperature 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, and it is easy to warp and deform above 90 degrees.

4. The plastic wall thickness should be uniform, avoiding lack of glue and sharp corners and preventing stress concentration.

use

Polypropylene fiber for engineering

Divided into polypropylene monofilament fiber and polypropylene mesh fiber.

Polypropylene mesh fiber is a kind of high-strength monofilament or mesh organic fiber made of modified polypropylene through extrusion, stretching, netting, surface modification and chopping. It has inherent strong acid resistance, strong alkali resistance, weak thermal conductivity and extremely stable chemical properties. Adding concrete or mortar can effectively control the micro-cracks of concrete (mortar) caused by solid plastic shrinkage, dry shrinkage, temperature change and other factors, prevent and inhibit the formation and development of cracks, and greatly improve the crack resistance, impermeability, impact resistance and seismic performance of concrete, which can be widely used in underground engineering waterproofing, roofing, wall, ground, pool, basement and so on. Industrial and civil construction projects, as well as road and bridge projects. It is an ideal new material for mortar/concrete engineering with anti-cracking, anti-seepage, wear resistance and heat preservation.

Biaxially oriented polypropylene film

Packaging materials play an extremely important role in plastic products. According to statistics, plastics used in the field of packaging in the world account for about 35% of the total plastic consumption. China's packaging plastics developed rapidly, with the output increasing rapidly from 1980 19000 tons to 4.65 million tons in 2003. It is estimated that it will exceed 5.5 million tons in 2005, 7 million tons in 2065 and 9 million tons in 2065, accounting for about 65,438+of the total national packaging output.

From the product point of view, the film for packaging accounts for more than 50% of the total plastic for packaging. The biaxially oriented polypropylene (BOPP) film in China is one of the areas with the largest consumption of polypropylene resin. In 2003, there were 86 BOPP production enterprises (123 production lines) with a total production capacity of about10.4 million t/a, and in 2004, it will reach 2 million t/a( 138 production lines), and the output will exceed 65,438. In recent years, domestic enterprises pay attention to improving product competitiveness, and have introduced a number of advanced BOPP production equipment. The film width can reach 8.3m, and the linear speed can reach 400~500m/min. For example, Zhejiang Dadongnan Group imported a 60,000 t/a production line from brukner. Guofeng Group invested 200 million yuan to introduce 35,000 t/a production line (BOPP equipment, width Asia 1, world10m); Changzhou Wujin Jinshi Group introduced Germany's 20,000 t/a five-story * * * extruded high-strength ultra-thin BOPP production line; Fujian Hyundai Group introduced 25,000 t/a production line; Baoshuo Group plans to introduce 65438+ 10,000 t/a production line. According to the current production capacity of BOPP film in China, the annual demand for PP resin is nearly 2 million tons. Therefore, attention should be paid to the development of BOPP film special materials with high linear speed, good ductility and good transparency, including matching polymers of ethylene and propylene, in order to adapt to the newly introduced BOPP film equipment.

Modified polypropylene for automobile

In 2003, China produced more than 4.4 million vehicles, ranking fourth in the world, with a year-on-year increase of 36.6%. According to the American ESM WerWide report: "In 2008, China's automobile output will exceed 6 million, and in 20 15, it will surpass Japan, ranking second in the world".

The development of automobile industry is inseparable from the process of automobile plasticization. At present, the self-sufficiency rate of engineering plastics in China is less than 16%. According to the forecast of China Engineering Plastics Association, the demand growth rate of engineering plastics in China in 2005 will be 15% and 20 10%, and the demand will increase from 440,000 t in 2000 to10.4 million t in 20 10. The demand for engineering plastics in China's automobile manufacturing industry is growing rapidly. By 20 10, the total consumption will reach 940,000 t (accounting for 5%~ 10% of the car weight).

PP is very competitive in the automobile industry, but it can't be directly used as automobile parts because of its low modulus and heat resistance and poor impact strength. The modified PP products are all used in automobiles, and the heat resistance can be improved from 80℃ to 145℃~ 150℃, and it can resist high temperature of 750~ 1000h without aging and cracking. It is reported that a new generation of high-orientation and high-crystallization polypropylene HEHCPP products introduced by Toyota Company of Japan can be used as automobile dashboard and bumper, which reduces the cost by 30% compared with similar products of TPO. Modified polypropylene has a very broad development prospect as an automobile part.

Polypropylene for household appliances

In recent years, China's home appliance industry has developed rapidly, with many varieties and large output. In 2003, the output of refrigerators, air conditioners, washing machines and microwave ovens in China were18.5 million, 42 million,/kloc-0.7 million and 35 million respectively. According to "2004-2006 China Urban Home Cinema Market Research and Consultation Report", it is estimated that the market scale of home cinema system in China will reach 6.9 million in the next three years. In addition, there is a huge potential market for small household appliances, which is an excellent business opportunity for modified PP. At present, some domestic plastic raw material manufacturers have developed special materials for washing machines, such as PP 1947 series and K7726 series, which have been welcomed by washing machine manufacturers. Therefore, in the next few years, efforts should be made to develop PP special materials for household appliances to meet the changing needs of the market.

Polypropylene for pipeline.

In 2003, the total output of plastic pipes in China exceeded 654.38+800,000 t, a year-on-year increase of 23%. In the early days, PP pipes were mainly used as agricultural water pipes, but due to some problems in the performance of early products (poor impact strength and aging resistance), the market failed to open. With the introduction of foreign advanced technology by Shanghai Plastic Building Materials Factory for the first time, the pipes for transporting cold and hot water produced with imported PP-R materials have been recognized by the market. At present, many manufacturers have built PP-R pipe production lines, and the initial production price has been 20,000 ~ 30,000 yuan /t, but the share of PP-R pipe in the plastic pipe market is still very low. It reflects that there is still a certain gap between domestic PP-R materials and imported materials, and the quality needs to be improved. It is reported that Korea has developed a new brand of random polypropylene PP-R 1 12 for high-pressure water supply pipes. The pipes produced by this brand can be used for 50 years at 20℃ and ultra-high pressure of 1 1.2MPa.

Plastic pipe is one of the key products in the popularization and application of chemical building materials in China. In 200 1 year, the Ministry of Construction issued the Notice on Strengthening the Production Management and Popularization of Polypropylene (PP-R, PP-B) Pipes, requiring relevant departments to do a good job in raw materials, processing, quality and even use and installation of pipes, and strictly control the quality of PP pipes to

High transparent polypropylene

With the continuous improvement of people's living standards, it will inevitably bring different requirements and improvements in culture, entertainment, diet, medical care, materials, room decoration and other aspects. Transparent materials are increasingly used in many items on the market. Therefore, it is a good development trend to develop transparent PP special materials, especially PP special materials with high transparency, good fluidity and fast molding, and design and process PP products that people like. Transparent PP has more characteristics, advantages and development prospects than ordinary PP, PVC, PET and PS.

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 companies in Germany use transparent PP instead of PVC；; The growth rate of American transparent PP products is 7% ~ 9% higher than that of ordinary PP products; In recent years, the annual consumption of PP nucleating transparent agent in Japan is about 2000t, and if the additive amount is 0.25%, the annual output of transparent PP material in Japan can reach more than 800,000 t. According to the statistics of Japan Physical and Chemical Corporation, the consumption of transparent PP special material in microwave ovens and furniture is the largest. It is estimated that the demand for transparent PP special materials in foreign markets in 2005 will be 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.

What's the difference between polyethylene, PVC, polystyrene and polypropylene?

When uncolored, it is milky white and translucent wax-like; Touching the product by hand feels greasy, soft and tough; Slightly scalable. Generally, low density polyethylene is soft and transparent; High density polyethylene is very hard.

Common products: handbags, water pipes, oil drums, beverage bottles (calcium milk bottles), daily necessities, etc.

Polypropylene PP

When uncolored, it is white, translucent and waxy; Lighter than polyethylene. Transparency is also better than polyethylene, which is harder than polyethylene.

Common products: pots, barrels, furniture, films, woven bags, bottle caps, car bumpers, etc.

Polystyrene PS

Transparent when colorless. When the product falls to the ground or knocks, it has a metallic crisp sound, good luster and transparency, similar to glass, fragile and easy to break, and can be used to mark the surface of the product with nails. Modified polystyrene is opaque.

Common products: stationery, cups, food containers, household appliance shells, electrical accessories, etc.

polyvinyl chloride

Natural color is yellowish, translucent and shiny. Transparency is better than polyethylene and polystyrene, but worse than polystyrene. With the different dosage of additives, it can be divided into soft PVC and hard PVC. Soft-packed products are soft and tough and sticky to the touch. The hardness of hard products is higher than that of low density polyethylene, but lower than that of polypropylene, and whitening will occur at the bending point.

Common products: plates, pipes, soles, toys, doors and windows, wire sheaths, stationery, etc.

Polyethylene terephthalate PET

Good transparency, better strength and toughness than polystyrene and PVC, and not easy to break.

Common products: often bottle products such as cola, mineral water bottles, etc.

Physical and electrical characteristics

project

Test project unit

Unit specification

Technical requirements test method

test method

melt index

Melt flow rate g/ 10 min 2.5 ASTM