Typical application range of PBT polybutylene terephthalate: household appliances (food processing blades, vacuum cleaner components, electric fans, coffee utensils, etc.), electrical components (switches, motor casings, computer keyboard keys, etc.), automotive industry (heat radiator window, wheel cover, door and window parts, etc.).
Injection Molding Process Conditions: Drying: This material is easily hydrolyzed at high temperatures, so drying prior to processing is important. It is recommended to dry in air at 120C, 6~8 hours, or 150C for 2~4 hours. The humidity must be less than 0.03%. If drying with a hygroscopic dryer, the recommended conditions are 150C, 2.5 hours?. Melting temperature: 225~275C, recommended temperature: 250C. Mold temperature: 40 to 60 C for unreinforced materials. The cooling channels of the mold are well designed to reduce the bending of the plastic parts. The loss of heat must be fast and even. It is recommended that the mold cooling channel has a diameter of 12 mm. Injection pressure: medium (up to 1500 bar). Injection speed: The injection speed should be as fast as possible (because PBT solidifies quickly).
Chemical and physical properties:
PBT is one of the toughest engineering thermoplastics. It is a semi-crystalline material with excellent chemical stability, mechanical strength, electrical insulation properties and thermal stability. These materials are very stable under a wide range of environmental conditions. PBT has a weak hygroscopic property. The tensile strength of the non-reinforced PBT is 50 MPa, and the tensile strength of the PBT of the glass additive type is 170 MPa. Excessive glass additives will cause the material to become brittle. PBT; crystallization is very rapid, which will cause bending deformation due to uneven cooling.
PMMA Polymethyl methacrylate Typical applications: automotive industry (signal equipment, instrument panels, etc.), pharmaceutical industry), industrial applications (video discs, light diffusers), consumer goods (beverage cups, stationery, etc.).
Injection Molding Process Conditions: Drying Treatment: PMMA is hygroscopic so that drying before processing is necessary. The recommended drying conditions are 90C for 2~4 hours. Melting temperature: 240~270C. Mold temperature: 35~70C. Injection speed: medium
Chemical and physical properties: PMMA has excellent optical properties and resistance to weathering. The penetration of white light is as high as 92%. PMMA products have very low birefringence and are especially suitable for making DVDs. PMMA has room temperature creep properties. As the load increases and the time increases, stress cracking can occur. PMMA has good impact resistance. The shrinkage rate is around 0.5%.
