Currently widely used in automotive, electrical and electronic, building, office equipment, packaging, sports equipment, health care and other fields, with the deepening of the modification, is rapidly expanding to high-tech fields such as aerospace, computer, CD. Application and development of PC resin: more than 70 s PC for electrical and electronic components such as connectors, switch to the first half of 80 s application to precision machinery (camera, clock and watch) machinery, electric tools and optics, became the first development of the PC. In the second half of the 80 s, the application of PC is further extended to the office equipment, cars, compact disc (CD), there is growing demand for and become the second development. After entering the 90 s is influenced by the economy slowing, but from 1992 to 1994 is still the growth rate of 10% ~ 15%. PC has large market capacity is because it has a comprehensive balance performance, excellent impact resistance, heat resistance, dimensional stability, transparency and self-extinguishing, so in electric, electronics, precision machinery, automobile, security, medical and other fields can be widely used as the engineering plastic. In the mid - 90 and PC/ABS alloy, multiple technology being developed, more expanded application fields.
The PC is widely used in automotive, electrical and electronic, building, office equipment, packaging, sports equipment, health care and other fields, with the deepening of the modification, is rapidly expanding to high-tech fields such as aerospace, computer, CD. PC alloy modification of PC/ABS alloy, PC and ABS blend can comprehensive the good performance of PC and ABS, improve the heat resistance, impact resistance and tensile strength of ABS, lowering the cost of the PC and the melt viscosity, improve the processing performance, reduce internal stress of products and the impact strength of the sensitivity of the product thickness. PC/ABS alloy is developing rapidly at present, the global output of about 800000 tons/year or so, the world's major companies new products launch of PC/ABS alloy, such as flame retardant, glass fiber reinforced, electroplating, uv resistance and other varieties, is widely used, especially in the automobile industry is also widely used in computers, copiers and electrical components, etc. In recent years has begun to research and production in China, such as Shanghai jie jie company of PC/ABS alloy material has been applied in automobile decoration, lamp shell and heat-resistant electrical shell; The Chinese academy of sciences changchun applied chemistry, the development of high heat resistance, high heat resistant, high impact, high heat-resisting flame-retardant three grade of PC/ABS alloy material has been used by several automobile manufacturing companies in China, used as decorative board, instrument panel and goods before lid is special material, etc.
Lanzhou university study in PC/ABS blend system with high pressure capacity of modified polyethylene, get good mixture flow and low temperature toughness and modulus is almost unaffected, suitable for making thin-wall plate; Domestic researchers in order to reduce the interface between the PC/ABS two-phase can, add impact resistant agent MBS in PC and ABS, alloy empty impact degree can reach high values, appearance of PC/ABS/MBS is ivory white, uniform texture, feel good. PC/PS alloy: this alloy is partially compatible, amorphous/amorphous. Add PS in PC can reduce PC viscous flow activation energy, thus improving PC processing liquid, add a small amount of PS can make the PC in the melt viscosity, PS in the PC can also play a role of rigid organic filler, PC and PS are transparent material, the refractive index is very close, so transparent, PC/PS alloy with good optical properties. PC/PS alloy composition of alloy had a greater influence on the mechanical properties, thermal properties and processing properties, with the increase of PS content, PC/PS system liquidity increases, the hardness, tensile strength and impact strength increase, and the thermal deformation temperature decreased. When the content of PS is at a certain value, the impact strength and tensile strength can be greatly valued. Therefore, a PC/PS alloy with high performance can be made by choosing the suitable ratio of PC and PS. And compatibilizers on the PC/PS blend system has a great influence on the performance, usually choose styrene, by causing a double bond in the end of the PC grafted styrene, get graft polymer is compatibilizers for PC/PS blend system, can greatly improve the compatibility of PC and PS, the material is suitable for making CD, etc.
In recent years the PC/PS alloy application scope expands unceasingly, new varieties constantly emerging, such as Japan's PC/PS alloy Novally x 7000, like ABS, easy on the lacquer and printing ink; Japan petrochemical light push Out of halogen PC/PS alloy series flame retardant, compared with flame retardant ABS, has high toughness, good liquidity, high rigidity, good flame retardant, etc. PC/PBT alloy, PBT, excellent mechanical properties, resistance to chemical corrosion and the characteristics of easy molding, PBT and PC blend alloy material can improve system PC liquidity, improve the processing performance and chemical resistance.
Because of PBT, is the crystallization of polymer, and PC blend used quoted separation, when the interface bonding is bad, thus its impact toughness is not ideal, usually add some elastomers in order to improve the impact strength of blend. For example, zinc-salt of thermoplastic elastomer vinyl/methacrylate copolymer has been used to increase and toughen the PC/PBT blend system. Addition of some crystalline nucleating agents can improve the crystallinity of the blend system. In the PC/PBT blend system, a small amount of low pressure polyethylene can be added to improve the fluidity of the blend, toughening the blending system and improving the appearance of the alloy. Adding ethylene/acetate copolymer to PC/PBT can further enhance compatibility and enhance impact strength. Esterification reaction taking place between PC and PBT, can improve the compatibility, researchers in Japan used PC and PBT, the ester exchange, in the presence of catalyst was prepared, PC/PBT blend comprehensive performance is good, and has a good transparency; The glass fiber reinforced PC/PBT with similar PC refractive index is not only excellent in comprehensive performance, but also good in transparency. Glass can be used as a substitute for materials. At present, the foreign PC/PBT alloy products are mainly used in automobile bumpers, packaging film materials, car base and seating etc. PC/PET alloy: PET has good mechanical properties and resistance to chemicals, PC/PET both PC rigidity and heat resistance, and solvent resistance of PET, and the addition of PET also can improve the processing fluidity of PC. The domestic researchers found that when PC/PET ratio was 1/3, the interface layer was formed between the two phases, when PC/PET compatibility was the best. Another PC and PET ester exchange reaction is one of the best way to improve the compatibility, the catalyst type selection effect on reaction is very big, through the study found that lanthanide catalyst compared with the traditional catalysts (such as titanium) has high catalytic activity, and no side effects, also found that the ester exchange reaction occurred mainly in two phase interface. In the PC/PET blend system, the addition of elastomers such as polyacrylate can improve the toughness and impact strength of the alloy. Current research and development on PC alloy with each passing day, there are a variety of PC alloys have been developed and to market, especially the polyester blend modified PC, such as PET/photo (by ethylene glycol, low molecular weight poly (caprolactone and terephthalic acid copolymer and become more block copolyesters) with PC blend modification; The blending of 1, 4 - cyclohexane dimethyl alcohol, ethylene glycol and terephthalic acid in polyester and PC can obviously improve the bending modulus and tensile strength of PC. Polyurethane is used as the reinforcing material of glass fiber, and the esters exchange catalyst is used to promote the blending and modification of polyhexyl ester and PC, which can get the transparent materials with good processing performance and high rigidity. Poly (1, 4 - cyclohexane diformate - 1, 4 - cyclohexane dimethyl alcohol) ester modified PC can significantly improve PC transparency and resistance to yellowing, which can be used as optical disk material. Liquid crystal polyester modified PC can be used to improve PC's melt processing performance and mechanical properties. With the development of PC alloy materials and the application scope of PC, the application scope of PC has been continuously expanded. The application fields of some domestic PC are briefly introduced. Wide wave transmission optical instruments: good performance engineering plastics, as a kind of transparent PC for optical disc substrate used heavily in the whole world, not only can the preparation of CD, VCD, DVD, you can also apply to high density recording disc substrate, especially the PC and the generation of styrene graft copolymer has good application effect. PC chips are especially suitable for eyeglasses, and the introduction of silica oxygen groups in PC chains can improve their hardness and abrasion resistance. PC as a high index of refraction of plastic, used to make high temperature optical fiber core material, if in the molecular chain of the PC - H chain of C - C F chain replaced, you can to visible light absorption, can effectively reduce the loss on the way of signals.
In PC good pervious to light, in a transparent window material high-rise building curtain wall, airports and stadiums transparent building materials and so on are very common and has the potential, the key is to improve the surface hardness and antistatic ability in the future. Flame retardant environmental communication appliances: as the PC good electrical insulating properties, are widely used in communications equipment, bakelite, PC has a large number of replacement for the original focus in future development of flame retardant PC used for communication in the field of electrical appliances, therefore become the development emphasis pollution-free flame retardant PC material, bromine flame retardants as reduce toxicity in use, environmental phosphorus-containing flame retardant and halogen free will obviously reduce the thermal deformation temperature and the impact strength of PC, thus is more suitable for organic silicon series resistance agent. In addition with lightweight miniaturization communication appliances put forward higher requirements for the PC material, the PC/ABS alloy is particularly suitable for application in the communication appliances and aerospace industries. Surface metallization of car parts: PC after surface metallization has good metallic luster and high strength, widely used in various kinds of auto parts, but in the process of electroplating can reduce its impact toughness, therefore the elastomer with PC blending modification, the elastomer scattered the cracking stress, although electroplating will not reduce its impact toughness, therefore very electroplating grade PC resin development prospects. Surface metallization of PC also can be used as electromagnetic shielding materials, used in the computer. Low residual harmful food containers: industrial synthesis of PC is bisphenol A righteous type, because there are traces of unreacted monomer synthesized bisphenol A residue in the resin, as A drinking water and food containers, vulnerable to dissolution and influence people health, thus to develop health level of PC resin, used for drinking water barrels and the production and use of other food containers, very bullish on domestic application prospects. Anti cracking embrittlement of medical equipment: PC has many excellent performance, has been used in medical equipment, due to its poor resistance to chemical character, in the presence of chemicals, easy cause internal stress cracking, such as PC in artificial dialyser, artificial lung used in medical equipment to solve high temperature disinfection lead to crack of aging, if to overcome these shortcomings, the PC application can be expanded rapidly in medical apparatus and instruments. PC resin material performance of PC (polycarbonate) is a colorless transparent engineering plastics, has a very high impact strength, the use of wide temperature range, good creep resistance, electrical insulation and dimensional stability, thermal stability, glossiness, inhibit bacteria, flame retardant properties and stain resistance; And low shrinkage rate, general is 0.1% ~ 0.2%. PC has good mechanical properties, but poor flow characteristics, therefore the injection molding process of the material is difficult. When choosing what quality of PC material, will eventually expect of the products as the benchmark. If required by the plastic parts to have higher impact resistance, then use PC material of low turnover; On the other hand, you can use the high turnover of PC material, it can optimize injection molding process. PC's biggest characteristics is a transparent plastic crystal type, forming good dimensional stability, from low to high temperature can maintain the stability of the mechanical strength, tensile and deformation characteristics of its more close to the metal materials, there is a obvious elastic limit. So the PC has been used as a structural material strength calculation can consult the formula of metal materials, at the beginning of the development of PC has a large number of lightweight transparent material is used instead of the metal. PC resin molding process: the process features of PC resin 1, state of aggregation property belongs to the amorphous non-crystalline plastic, no obvious melting point, high melt viscosity. Glass transition temperature of 140 ° ~ 150 ℃, the melting temperature of 215 ℃ ~ 225 ℃, the molding temperature 250 ℃ ~ 320 ℃. 2, in the normal processing temperature range and internal stability is better, 300 ℃ long stay the basic decomposition, not more than 340 ℃ starts to break down, is influenced by shear rate viscosity is smaller. 3, rheological property close to Newton fluid, the apparent viscosity is strongly influenced by temperature, less influenced by shear rate, the increasing of relative molecular mass. A benzene ring in the PC molecular chains, so molecular chain rigidity. 4, good creep resistance of PC, good dimensional stability; But it is not easy to eliminate internal stress. 5, PC easy degradation under the influence of water under high temperature, molding requirements when moisture content is below 0.02%.