Polypropylene English name: Polypropylene
Japanese name: ポリプロピレン
Molecular Formula: [C3H6]n
CAS Registry Number: 9003-07-0
Abbreviation: PP,
Polymerization of propylene produced by a thermoplastic resin. There are three configurations: isotropic, atactic and mesotropic, with isotropic as the main component of industrial products. Polypropylene also includes propylene and a small amount of ethylene **** polymer. Usually translucent colorless solid, odorless and non-toxic. Due to the structure of the regular and highly crystallized, so the melting point of up to 167 ℃, heat-resistant, products can be sterilized by steam is its outstanding advantage. Density 0.90g/cm3, is the lightest general-purpose plastic. Corrosion resistance, tensile strength of 30MPa, strength, rigidity and transparency are better than polyethylene. Disadvantages are poor low-temperature impact resistance, easier to age, but can be overcome by modification and addition of antioxidants, respectively.
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 temperatures, not wear-resistant, easy to aging. Suitable for the production of general mechanical parts, corrosion-resistant parts and insulating parts. Common acids, alkalis and organic solvents have little effect on it, and it can be used for eating utensils.
Production methods:
① Slurry method. Polymerization in diluent (such as hexane), is the earliest industrialized and by far the largest production method. ② Liquid phase native method. Polymerization in liquid propylene at 70℃ and 3MPa. ③ Gas phase method. Polymerization of propylene in a gaseous state. The latter two methods do not use diluents, have short processes and low energy consumption. Liquid-phase propriety method has now shown later advantages.
Molding characteristics:
1. Crystalline material, hygroscopic, easy to melt rupture, easy to decompose in contact with hot metal for a long time.
2. Good fluidity, but shrinkage range and shrinkage value is large, easy to occur shrinkage hole. Dents, deformation.
3. Cooling speed, pouring system and cooling system should be slow heat dissipation, and pay attention to control the molding temperature. Material temperature low temperature and high pressure is easy to orientation, mold temperature is lower than 50 degrees, the plastic is not smooth, easy to produce poor fusion, flow marks, more than 90 degrees prone to warping and deformation
4. Plastic wall thickness should be uniform, to avoid the lack of glue, sharp corners, in order to prevent stress concentration.
Polypropylene molding process:
Injection molding process conditions:
Drying process: If the storage is appropriate, no drying process.
Melting temperature: 220 ~ 275C, be careful not to exceed 275C.
Mould temperature: 40 ~ 80C, it is recommended to use 50C. The degree of crystallization is mainly determined by the mold temperature. Injection pressure: can be as big as 1800bar.
Injection speed: usually, using high speed injection can minimize the internal pressure. If defects appear on the surface of the product, then lower injection speeds at higher temperatures should be used.
Runners and Gates: For cold runners, typical runner diameters range from 4 to 7 mm. injection ports and runners with round bodies are recommended. All types of gates can be used. Typical gate diameters range from 1 to 1.5 mm, but gates as small as 0.7 mm can be used. For edge gates, the minimum gate depth should be half the wall thickness; the minimum gate width should be at least twice the wall thickness. PP materials are fully compatible with hot runner systems.
PP is a semi-crystalline material. It is harder than PE and has a higher melting point. Since homopolymer type PP is very brittle at temperatures above 0C, many commercial PP materials are irregular **** polymers with 1 to 4% ethylene or higher ratio ethylene content of clamped **** polymers. Polymer type PP materials have a lower heat distortion temperature (100C), low transparency, low gloss, low rigidity, but have greater impact strength. the strength of PP increases with increasing ethylene content. the Vicat softening temperature of PP is 150C. due to the high degree of crystallinity, the surface stiffness and scratch resistance of this material is very good. there is no problem of environmental stress cracking in PP. Typically, PP is modified by adding glass fibers, metal additives, or thermoplastic rubber.The flow rate MFR of PP ranges from 1 to 40.PP materials with low MFR have better impact characteristics but lower ductile strength. For the same MFR, the *** polymer type is stronger than the homopolymer type. Due to crystallization, the shrinkage of PP is quite high, generally 1.8 to 2.5%. And the directional uniformity of shrinkage is much better than materials such as PE-HD. Adding 30% glass additive can reduce the shrinkage to 0.7%. Both homopolymer-type and *** polymer-type PP materials have excellent resistance to moisture absorption, acid and alkali corrosion, and solubility. However, it has no resistance to aromatic hydrocarbon (e.g. benzene) solvents, chlorinated hydrocarbon (carbon tetrachloride) solvents, etc. PP also does not have oxidation resistance even at high temperatures like PE. [/font]
Uses
Engineering polypropylene fibers
Divided into polypropylene monofilament fibers and polypropylene mesh fibers
Polypropylene mesh fibers to modified polypropylene as raw materials, through the extrusion, stretching, netting, surface modification, such as short-cutting and other processes and become a high-strength bundled monofilament or mesh organic fibers, the intrinsic resistance to acid, alkali, weak thermal conductivity, and so on. Strong alkali resistance, weak thermal conductivity, with extremely stable chemical properties. Add concrete or mortar can effectively control the concrete (mortar) solid plastic shrinkage, dry shrinkage, temperature changes and other factors caused by micro-cracks, to prevent and inhibit the formation and development of cracks, and greatly improve the crack-blocking and seepage-resistant properties of concrete, impact resistance and seismic capacity, can be widely used in underground waterproofing, industrial and civil construction projects, such as roofs, walls, floors, pools, basements, as well as roads and bridges. bridge projects. It is the new ideal material for mortar/concrete engineering anti-cracking, anti-seepage, wear-resistant, heat preservation
Biaxially oriented polypropylene film
Packaging materials occupy an extremely important position in plastic products, according to statistics, the world's plastics used in the field of packaging accounted for about 35% of the total consumption of plastics. China's rapid development of plastics for packaging, production from 1980, 190,000t quickly increased to 4.65 million tons in 2003, is expected to exceed 5.5 million tons in 2005, more than 7 million tons in 2010, more than 9 million tons in 2015, accounting for more than 13% of the country's total output of packaging.
From the product point of view, packaging film accounts for about 50% of the total packaging plastics. China's biaxially oriented polypropylene (BOPP) film is one of the largest areas of consumption of PP resin, in 2003, China has 86 BOPP manufacturers (123 production lines), with a total production capacity of about 1.4 million t / a, in 2004 to reach 2 million t / a (138 production lines), the output will break through the 1 million t. In recent years, the domestic enterprises to focus on improving the competitiveness of their products. Has introduced a number of advanced BOPP production equipment, the production of film width up to 8.3m, line speed up to 400-500m/min, such as Zhejiang Dazhongnan Group introduced the German Bruckner 60,000t / a production line; Guofeng Group invested 200 million yuan to introduce the 35,000t / a production line (currently Asia's first, the world's fourth 10m wide BOPP equipment); Changzhou, Wujin Jin Group introduced Germany 20,000t / a five-layer *** extrusion of high-strength ultra-thin BOPP production line; Fujian Modern Group introduced 25,000t / a production line; Baoshuo Group plans to introduce 100,000t / a production line. According to China's existing BOPP film production capacity conversion, the annual demand for PP resin nearly 2 million tons, so attention should be paid to the development of BOPP film with high line speed, extensibility, transparency and good PP special materials, including supporting the use of ethylene and propylene **** polymer to adapt to the new introduction of BOPP film equipment.
Modified polypropylene for automotive
In 2003, China's automobile production of more than 4.4 million units, has ranked fourth in the world, an increase of 36.6%. According to the U.S. ESM WerWide reported: "China's automobile production in 2008 will exceed 6 million units, 2015 will exceed Japan, jumped to the world's second place".
The development of the automotive industry is inseparable from the process of automotive plastics, the current self-sufficiency rate of engineering plastics in China is less than 16%. According to the China Engineering Plastics Association predicted that China's engineering plastics demand growth rate of 15% in 2005, about 10% in 2010, the demand will grow from 440,000t in 2000 to 1.4 million t in 2010. China's automobile manufacturing industry on the rapid growth in demand for engineering plastics, the total amount of use by 2010 will reach 940,000t (to the amount of plastics accounted for the weight of the automobile 5%~10%)
Plastic is used in the manufacture of automobiles.
PP used in the automotive industry has a strong competitiveness, but because of its modulus and heat resistance is low, poor impact strength, so can not be directly used as automotive parts, cars in the use of modified PP products, its heat resistance can be increased from 80 ℃ to 145 ℃ ~ 150 ℃, and can withstand high temperatures of 750 ~ 1,000h after not aging, not cracking. It is reported that Japan Toyota launched a new generation of highly oriented crystalline polypropylene HEHCPP products, can be used as automotive instrument panels, bumpers, than TPO as raw material for the production of similar products to reduce the cost of 30%, modified PP used as automotive parts has a very broad development prospects.
Household appliances with polypropylene
In recent years, China's household appliances industry is developing rapidly, with many varieties and large output. 2003 China's refrigerator production of 18.5 million units, 42 million air conditioners, washing machines 17 million units, microwave ovens 35 million units. According to the "2004~2006 China Urban Home Theater Market Research and Consulting Report", it is expected that in the next three years China's home theater system market size will reach 6.9 million units. In addition, a variety of small appliances also has a huge potential market, which is an excellent business opportunity for modified PP. At present, some of China's plastic raw materials manufacturers 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 should increase the development of PP special materials for household appliances 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, an increase of 23%. Early, PP pipe is mainly used as agricultural water pipeline, but because of the early product performance there are still some problems (impact strength, aging resistance is poor), the market failed to open. With the Shanghai Plastic Building Materials Factory was the first to introduce advanced foreign technology, the use of imported PP-R materials produced by the transmission of cold and hot water with the pipe is recognized by the market, there have been many manufacturers to build PP-R pipe production line, the price is also put into production by the early 20,000 ~ 30,000 yuan / t continued to fall, but PP-R pipe in the plastic pipe market share is still very low. It is reflected that the current domestic PP-R materials and imported materials still have a certain gap, the quality needs to be improved and enhanced. It is reported that South Korea has developed a high-pressure water supply pipe with no rules **** polypropylene PP-R 112 new grade, the use of the grade production of pipes can be in 20 ℃ and 11.2MPa ultra-high-pressure state of use for 50 years.
Plastic pipe is China's chemical building materials to promote the application of one of the key products, the Ministry of Construction was issued in 2001 "on strengthening *** polypropylene (PP-R, PP-B) pipe production management and promotion of the application of the work of the notice", requiring the relevant departments *** with the do a good job from raw materials, processing, quality to the use of pipe, installation and so on. Pipe use, installation and other work, we must strictly good PP pipe quality, in order to better do a good job in China's PP pipe production, application, promotion work.
Highly transparent polypropylene
As people's living standards continue to improve, will inevitably bring in culture, entertainment, food, medical, materials, home decoration and other aspects of different changes in the requirements and improve the market, many items more and more use of transparent materials. Therefore, the development of transparent PP special materials is a good development trend, especially the need for high transparency, good fluidity, fast molding PP special materials, in order to design and process into people's favorite PP products. Transparent PP has more characteristics than ordinary PP, PVC, PET, PS, and has more advantages and development prospects.
In recent years, foreign transparent PP market is growing rapidly, such as South Korea's LG will be transparent PP as a PET alternative to the market; Germany, some companies use transparent PP instead of PVC; the United States, transparent PP products, the growth rate is higher than the ordinary PP products 7% to 9%; Japan in recent years, the annual consumption of PP nucleating transparent agent is about 2,000t, if the amount of additive 0.25% projected that the annual output of Japan's transparent PP material can reach up to 1,000t. The annual output of transparent PP material can reach more than 800,000t. According to the Japanese Ricoh Co., Ltd, Japan's transparent PP special materials for microwave cookware and furniture in two areas of the largest consumption. It is expected that in 2005, the foreign market demand for transparent PP special material is about 5 million to 5.5 million t. At present, the gap between domestic transparent PP special material and foreign countries is large, transparent PP resin and its products, the production and application of the products still need to be strengthened.
Polyethylene polyvinyl chloride polystyrene polypropylene What is the difference between polyethylene PE
Uncolored milky white semi-transparent, waxy; touch the products have a slippery feeling, soft and tough; slightly elongated. General low-density polyethylene is softer, better transparency; high-density polyethylene is harder.
Common products: handbags, water pipes, oil drums, beverage bottles (calcium milk bottles), daily necessities and so on.
Polypropylene PP
Uncolored white translucent, waxy; lighter than polyethylene. Transparency is also better than polyethylene, rigid than polyethylene.
Common products: pots, buckets, furniture, film, woven bags, bottle caps, car bumpers, etc..
Polystyrene PS
Transparent when not colored. Products fall to the ground or knock, there is a metal-like crisp sound, gloss and transparency is very good, similar to glass, brittle and easy to break, with fingernails can be scratched on the surface of the product. Modified polystyrene is opaque.
Common products: stationery, cups, food containers, home appliance shells, electrical fittings, etc.
Polyvinyl Chloride PVC
The original color is yellowish translucent, shiny. Transparency better than polyethylene, polystyrene, worse than polystyrene, with different amounts of additives, divided into soft and hard PVC, soft products are soft and tough, sticky feel, hard products, the hardness is higher than the low-density polyethylene, but lower than the polypropylene, in the bending place there will be a phenomenon of whitening.
Common products: plates, tubes, shoe soles, toys, doors and windows, wire sheaths, stationery, etc.
Polyethylene terephthalate PET
Very good transparency, strength and toughness is better than polystyrene and polyvinyl chloride, not easy to break.
Common products: often bottle products such as Coke, mineral water bottles, etc.
Physical and electrical properties
Item
Test Item Unit
Unit Specification
Technical Requirements Test Method
Test Method
Melt Index
Melt Flow Rate g/10min 2.5 ASTM
D1238
Density
Density g/cm3 0.91 ASTM
D1505
Tensile Strength
Tensile Strength MPa 21 ASTM
D638
Elongation at Break
Elongation at Break % 600 ASTM
D638
Brittle Temperature with Low Temperature
Low Temperature Brittle Temperature ℃ - 35 ASTM
D746
20℃ Volume Resistivity
20℃ Volume Resistivity Ω?m 1.6×1014 ASTM
D257
20℃ Dielectric Strength, 50Hz
Dielectric Strength, 50Hz MV/m 35 ASTM
D149
20℃ Dielectric Constant
Dielectric Constant --- 2.22 ASTM
D150
Dielectric Dissipation Factor
Dielectric Dissipation Factor --- 0.0003 ASTM
D150
Air Aging Condition
Hot Air Aging Condition
135℃×168h Tensile Strength Variation After Aging
Tension Tensile Strength Variation % ≤±25 ASTM
D3045
Elongation Variation After Aging
Fracture Elongation Variation % ≤±25
[Edit Paragraph]Polypropylene Industry in China
China's polypropylene industry began in the 1970s, after more than 30 years of development, has basically been the first time that China's polypropylene industry is the first time. After more than 30 years of development, has basically formed a solvent method, liquid-phase body - gas-phase method, intermittent liquid-phase body method, gas-phase method and a variety of production processes side by side, large and medium-sized production scale **** the existence of the production pattern. Now China's large-scale polypropylene production units are mainly based on imported technology, and medium-sized and small polypropylene production units are mainly based on localized technology.
China's polypropylene production in the next few years will have greater growth, but production is still insufficient to supply demand, China has become the world's largest net importer of polypropylene. However, due to the rapid growth of domestic production, import dependence is generally on a downward trend. China's polypropylene in the next few years, apparent consumption will remain high growth rate, imports will increase, polypropylene industry in China has a bright future.