PET plastic name
PET plastic name
Chinese name: polyethylene terephthalate
English name: polyethylene terephthalate (referred to as PET)
The nature of PET plastic
PET: density 1.30～1.38
Processing temperature 260-290
Mold temperature 140
Shrinkage 1.2-2.0
Melting point 245-260 degrees.
PET Plastic-Overview
PET is a milky white or light yellow, highly crystalline polymer with a smooth and shiny surface. It has excellent physical and mechanical properties in a wide temperature range, long-term use temperature can reach 120 ℃, excellent electrical insulation, even at high temperature and high frequency, its electrical performance is still good, but the corona resistance is poor, anti- Creep, fatigue resistance, friction resistance, and dimensional stability are all very good.
PET has ester bonds, which will decompose under the action of strong acid, strong alkali and water vapor, and it has good resistance to organic solvents and weather resistance. The disadvantage is that the crystallization rate is slow, the molding process is difficult, the molding temperature is high, the production cycle is long, and the impact performance is poor. Generally, the processability and physical properties are improved by means of reinforcement, filling, blending, etc., and the glass fiber reinforcement effect is obvious, and the rigidity, heat resistance, chemical resistance, electrical performance and weather resistance of the resin are improved. However, the disadvantage of slow crystallization speed still needs to be improved, and the addition of nucleating agents and crystallization accelerators can be adopted. Adding flame retardants and anti-flaming dripping agents can improve the flame retardancy and self-extinguishing properties of PET.
PET plastic properties
Polyethylene terephthalate (PET)
PET: density 1.30～1.38
Processing temperature 260-290
Mold temperature 140
Shrinkage 1.2-2.0
Melting point 245-260 degrees.
PET is a milky white or light yellow, highly crystalline polymer with a smooth and shiny surface. It has excellent physical and mechanical properties in a wide temperature range, long-term use temperature can reach 120 ℃, excellent electrical insulation, even at high temperature and high frequency, its electrical performance is still good, but the corona resistance is poor, anti- Creep, fatigue resistance, friction resistance, and dimensional stability are all very good.
PET has ester bonds, which will decompose under the action of strong acid, strong alkali and water vapor, and it has good resistance to organic solvents and weather resistance. The disadvantage is that the crystallization rate is slow, the molding process is difficult, the molding temperature is high, the production cycle is long, and the impact performance is poor.
Generally, the processability and physical properties are improved by means of reinforcement, filling, blending, etc., and the glass fiber reinforcement effect is obvious, and the rigidity, heat resistance, chemical resistance, electrical performance and weather resistance of the resin are improved. However, the disadvantage of slow crystallization speed still needs to be improved, and the addition of nucleating agents and crystallization accelerators can be adopted. Adding flame retardants and anti-flaming dripping agents can improve the flame retardancy and self-extinguishing properties of PET.
Polyterephthalic acid plastics mainly include polyethylene terephthalate (PET) and polybutylene terephthalate (PBT).
PET has a highly symmetric molecular structure and a certain degree of crystal orientation, so it has high film-forming and forming properties. PET has good optical properties and weather resistance, and amorphous PET has good optical transparency. In addition, PET has excellent abrasion resistance, dimensional stability and electrical insulation.
PET bottles are widely used because of their strength, good transparency, non-toxicity, impermeability, light weight, and high production efficiency. The structure of PBT and PET molecular chains is similar, and most of the properties are also the same, except that the main chain of the molecule is changed from two methylene groups to four, so the molecule is more flexible and the processing performance is more excellent.
PET plastic use
Films and sheets: all kinds of food, medicine, non-toxic and sterile packaging materials; high-end packaging materials for textiles, precision instruments, electrical components; audio tapes, video tapes, movie films, computer floppy disks, metal coatings and photosensitive films, etc. Base materials; electrical insulation materials, capacitor films, flexible printed circuit boards and membrane switches and other electronic and mechanical fields.
The application of packaging bottles: its application has developed from the original carbonated beverages to the current beer bottles, edible oil bottles, condiment bottles, medicine bottles, cosmetic bottles, etc.
Electronic appliances: manufacturing connectors, coil bobbins, integrated circuit housings, capacitor housings, transformer housings, TV accessories, tuners, switches, timer housings, automatic fuses, motor brackets and relays. Auto parts: such as switchboard covers, ignition coils, various valves, exhaust parts, distributor covers, measuring instrument covers, small motor covers, etc., PET can also be used to make cars with excellent paintability, surface gloss and rigidity Exterior parts.
5
PP
PP plastic-name
Chinese Name: Polypropylene
English name: Polypropylene
Properties of PP plastic:
Specific gravity: 0.9-0.91 g/cm3
Mold shrinkage: 1.0-2.5%
Molding temperature: 160-220℃
Melting temperature: 220~275℃, be careful not to exceed 275℃.
Mold temperature: 40~80℃, 50℃ is recommended. The degree of crystallization is mainly determined by the mold temperature. Injection pressure: can be as large as 1800bar.
The melting point of PP is: 165～170℃
Decomposition temperature: 350℃
Maximum crystallization rate temperature: 120～130℃
Wide molding temperature range: 205～315℃
The suitable MFR range of PP for injection molding is: 2～15 g/10min. The fluidity of the melt is good. The barrel temperature is controlled at 210～280℃. The nozzle temperature is lower than the maximum temperature of the barrel: 10～30℃
PP Plastic-Overview
Polypropylene (PP plastic) is another excellent resin variety developed after nylon. It is a linear polymer with high density, no side chains, and high crystallinity. It has excellent comprehensive properties. It is white, translucent and waxy when uncolored; lighter than polyethylene. Transparency is also better than polyethylene and stiffer than polyethylene.
PP plastic properties
1. Crystal material, low hygroscopicity, prone to melt fracture, 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, dents and deformation are easy to occur.
3. The cooling speed is fast, the pouring system and the cooling system should dissipate heat slowly, and pay attention to controlling the molding temperature. The direction of the material temperature is low. The direction is obvious. Especially when the temperature is low and high, the mold temperature is less than 50 degrees, the plastic parts are not smooth, easy to produce Poor welding, leaving traces, warping deformation easily occurs above 90 degrees
PP plastic use
Automotive industry: (PP mainly containing metal additives: fenders, ventilation pipes, fans, etc.), instruments (dishwasher door gasket, dryer ventilation tube, washing machine frame and cover, refrigerator door gasket, etc.), Consumer goods (lawn and garden equipment such as lawnmowers and sprinklers, etc.).
