20 kinds of plastic properties of 16-20

Injection molding conditions: drying: before processing should ensure that humidity below 0.1%. If the material is exposed to the air storage, it is recommended to air dry in the 85C heat 4 to 5 hours. If the material is stored in a sealed container, then the balance after three hours the temperature can be used directly. 

 

Melting temperature: 240 ~ 300C; for common characteristics of materials not to exceed 310C, flame-retardant properties of materials for no more than 270C. 

 

Mold temperature: for unreinforced materials 30 ~ 40C, or a large area for the thin-walled components is 80 ~ 90C, for enhanced material 90 ~ 100C. Increase in temperature will increase the material's crystallinity. Precise control of mold temperature on the PA12 is very important. Injection pressure: maximum to 1000bar (recommended minimal pressure and high melting temperature). Injection speed: speed (for a glass additive material better). 

 

Runners and gates: For non-additive materials, due to lower material viscosity, flow channel diameter should be about 3mm. Materials required for the enhanced 5 ~ 8mm diameter of the crowd said. Flow should shape all round. Note the entrance should be as short as possible. You can use various forms of gate. Do not use large plastic small gate, which is the plastic parts in order to avoid excessive pressure or excessive shrinkage. Gate thickness equal to the best and the thickness of plastic parts. If the submarine gate, the proposed minimum diameter of 0.8mm. Hot runner mold is very effective, but requires very precise temperature control to prevent material leakage or freezing in the nozzle. If you use the hot runner, gate size should be smaller than the cold runner. 

 

Chemical and physical properties: PA12 from butadiene linear, semi-crystalline - crystalline thermoplastic material. It features and PA11 similar, but different crystal structure. PA12 is a good electrical insulator and as polyamide and other moisture will not affect the insulation performance. It has good chemical stability, impact resistance machines. PA12 has many features and enhancements in the plastics area of ​​improved varieties. PA6 and PA66, and compared these materials have a lower melting point and density, with a very high moisture regain. PA12 free of strong oxidizing acid resistance. PA12 viscosity depends on humidity, temperature and storage time. It's good liquidity. Shrinkage of 0.5% to 2%, depending on the variety of materials, thickness and other process conditions. 

 

PS polystyrene Typical applications: packaging household items tableware, trays, etc., electrical (transparent container, light scattering devices, insulating film, etc.).

 

Injection molding conditions: drying: Unless stored properly, usually does not require drying. If drying is recommended drying conditions for the 80C, 2 ~ 3 hours. Melting temperature: 180 ~ 280C. Flame-retardant materials for the upper limit of 250C. Mold Temperature: 40 ~ 50C. Injection pressure: 200 ~ 600bar. Injection speed: It is recommended to use a fast injection speed. Runners and gates: You can use all conventional types of gate. 

 

Chemical and physical properties: most of the commercial use of PS is transparent, non-crystalline materials. PS has a very good geometric stability, thermal stability, optical transmission properties, electrical insulating properties and a very small moisture tendencies. It is resistant to water, diluted inorganic acids, but can be strong oxidizing acids such as concentrated sulfuric acid are corrosive and can in some organic solvents in the swelling deformation. Typical shrinkage of 0.4 to 0.7 percent. 

 

PVC (polyvinyl chloride) Typical Applications: water supply pipes, home pipes, house siding, commercial machine housing, electronics packaging, medical devices, food packaging. 

 

Injection molding conditions: drying: usually does not require drying. Melting temperature: 185 ~ 205C. Mold Temperature: 20 ~ 50C injection pressure: can be as large 1500bar holding pressure: injection speed can be as large as 1000bar: To avoid material degradation, the general use of the injection speed considerably. Runners and gates: the gate can be any conventional use. If the processing of smaller components, it is best to use the needle-type gate or sneak into the gate; for thicker parts, it is best to use fan-shaped gate. Needle-type gate or sneak into the gate of the minimum diameter should be 1mm; fan. The thickness of the gate can not be less than 1mm. 

 

Chemical and physical properties: rigid PVC is the most widely used plastic materials. PVC material is a non-crystalline materials. PVC materials are often added in the actual use of stabilizers, lubricants, auxiliary processing agents, pigments, impact agents and other additives. PVC material with easy-flammable, high strength, excellent resistance to climate variability and geometric stability. PVC of oxidants, reducing agents and strong acids have a very strong resistance. However, it can be concentrated oxidizing acids such as sulfuric acid, concentrated nitric acid are corrosive and does not apply and aromatic hydrocarbons, chlorinated hydrocarbons in contact situations. PVC in the melt processing temperature is a very important process parameters, if this parameter properly will result in material decomposition problem. Very poor flow characteristics of PVC, the process very narrow range. Especially the high molecular weight PVC material more difficult to process (this material is usually added to improve the flow of lubricant properties), so commonly used are low molecular weight PVC material. PVC shrinkage rate is very low, generally 0.2 to 0.6%. 

 

SA styrene - acrylonitrile copolymer Typical applications: electric socket, shell, etc., household goods Kitchen equipment, refrigerator units, TV chassis, cassette boxes, automotive (car headlights box, reflective environment, instrument panel, etc.) , household items (cutlery, food and tools, etc.), cosmetics packaging. 

 

Injection molding conditions: drying: If stored improperly, SA has some of the moisture absorption characteristics. Recommended drying conditions for the 80C, 2 ~ 4 hours. Melting temperature: 200 ~ 270C. If the processing of thick-walled products can be used below the lower limit of the melting temperature. Mold Temperature: 40 ~ 80C. For enhanced materials, mold temperature should not exceed 60C. Cooling system must be designed well, because the mold temperature will directly affect the product's appearance, shrinkage and bending. Injection pressure: 350 ~ 1300bar. Injection speed: It is recommended to use high-speed injection. Runners and gates: the gate can be any conventional use. Gate size must be very appropriate to avoid stripes, burnt spots and voids. 

 

Chemical and physical properties: SA is a hard, transparent material. Styrene component to SA hard, transparent and easy to process; acrylonitrile component that SA has the chemical stability and thermal stability. SA has a strong ability to withstand load, anti-chemical ability, thermal stability, deformation characteristics and geometry. SA in glass fiber additives can increase the strength and heat deformation, reducing the coefficient of thermal expansion. SA Vicat softening temperature of about 110C. Load deflection temperature of about 100C. SA shrinkage rate of about 0.3 to 0.7%. 

 

Allyl resin 

 

Allyl-based class is allyl esters. Acid or a dollar-based dicarboxylic acid allyl monomer or can be used as a low viscosity thermoplastic prepolymer. They are often used as the unsaturated resin crosslinking agent, also used in reinforced thermosetting molding materials processing and high-performance transparent molding materials. 

 

Resin in hot and humid conditions, still maintain their electrical properties, molding products dimensional stability, chemical resistance, mechanical strength and heat resistance and good. Allyl added flame retardant molding resin can be purchased to Shangwang, some species have been recognized by Underwriters Laboratories United States. Some of the resin, with its thin specimen testing, with a fire resistant UL94 V-0 grade combustible degree level and have strong anti-ignition of the arc and arc track resistance of. 

 

Chemistry and Properties 

 

The most widely used business class is allyl diallyl phthalate acid and isophthalic acid diallyl monomers and prepolymers, which are easily converted into thermosetting molding compounds and the glass cloth and paper prepreg. 

 

Diethylene glycol bis (allyl carbonate) 

 

Because of its excellent transparency needed, use more widely. As the lightweight, dimensionally stable, wear-resistant, easy to color, it is the production of the main material of plastic lenses. Other applications include instrument panel cover, camera filters, and the rapid growth of the glass industry in all areas. 

 

Recently, the emergence of a modified bisphenol A bis (allyl carbonate), which is a transparent polymer, has a high refractive index (1.56), compared with diethylene glycol bis (allyl carbonate) The refractive index is higher. In addition, there is a modified version for lens design, can change the lens design. In addition some single value of the goods is diallyl fumarate and diallyl maleate. This is a high response capability of the three monomers, containing two double bonds available for polymerization. Allyl methacrylate has bifunctional properties, can be used as crosslinking agent and monomer intermediates. Diallyl cyanurate can be used as the crosslinking of unsaturated polyester resins. 

 

A typical catalyst system is peroxide, tert-butyl ester as too acid, benzoic acid Dicumyl peroxide or peroxide, they have sufficient thermal stability, sustainable best friends together to complete. Best of devaluation diethylene glycol bis (allyl carbonate) and carbonate peroxide Diisopropyl, because they are not only the color is very light, but also has a high degree of transparency. Dosage of initiator per 100 parts resin is generally 2 to 3 servings. 

 

Classification 

 

Molding grade is mainly fiber-filled, filled with fiber, including mineral fibers, glass fibers, synthetic fibers. Such molded products in the hot and humid conditions with excellent electrical properties, low loss factor. High surface resistance and volume resistance, high resistance to arc and track resistance of the arc. Diallyl phthalate acid strength of the insulation value of 374 ° F was still good, and isophthalic acid diallyl can exceed 400 ° F was still good. 

 

Application 

 

Most of diallyl phthalate acid compound commonly used in electrical or electronic equipment, a key component of the harsh environmental conditions to ensure a high degree of reliable performance. 

 

A very important application areas in the communications, computer, aerospace systems in the application of electrical connection devices, other applications including insulation, potentiometers, circuit boards, switches, TV components, etc., these polymeric materials and refinement of modern electronic technology, such as steam consolidation of technology with a high degree of matching. 

 

Reinforced plastics. Allyl resin pre-impregnated glass cloth or roving, and can be made pipes, conduit, antenna covers, junction boxes, aircraft and missile components. 

 

Polyester with allyl monomers. Some of the allyl monomer widely used as a pre-formed pieces of polyester felt adhesive or crosslinking agent, and the laminated prepreg material blank or shop wet cross-linking is also widely used in pure materials, aggregates and pre- mixed-mode plastic, and glass cloth with decorative layer forming the processing complex. As the molding temperature conditions, low vapor pressure, 302 ° F when 2.4mmHg, therefore, in the manufacture of finished products, especially big-ticket manufactured products, the commonly used acid diallyl phthalate, or other low-volatile allyl monomer, and less use of styrene. 

 

Because of its low volatility, it is more styrene allyl polyester polyester can be molded at higher temperatures, and thus faster molding cycle.