The special screw has a glass transition temperature of […]
The special screw has a glass transition temperature of 105 ° C, a melting temperature of more than 160 ° C, a decomposition temperature of 270 ° C, and a wide molding temperature range of 180-250 ° C. The special screw has high viscosity, poor fluidity, and is sensitive to the shear rate. The temperature is strictly controlled during the molding process. The barrel temperature is 240 ℃ -250 ℃, and the retention time does not exceed 8 minutes when it exceeds 260 ℃.
The special screw material uses high-quality SACM645, 38CrMoAla alloy steel as the base material, and the imported bimetal layer is welded on the top of the screw to increase the wear and corrosion resistance of the screw. Its effective service life is more than doubled than that of ordinary nitriding screws. The special screw is a layer of 1.5-3mm wear-resistant, corrosion-resistant, high-temperature resistant alloy that is centrifugally cast on the inner wall of the barrel. Its effective service life is greatly improved compared with ordinary nitrided barrels, which increases the wear life.
The special screw has low viscosity, good fluidity, relatively obvious melting point, poor thermal stability, high water absorption, dryer temperature of 80 ° C, no more than 120 ° C, and time of 16 hours. If the raw materials are exposed to air for 8 hours, use a vacuum oven at about 105 ° C for 12 hours. Non-crystalline plastic, no obvious melting point, glass transition temperature 140 ° C-160 ° C, melting temperature 215 ° C-225 ° C, molding temperature 230 ° C-320 ° C. The special screw has high viscosity, high processing temperature, narrow range, and easy to decompose. It avoids overheating when selecting the screw, is sensitive to moisture, and the resin is easy to hydrolyze at high temperature. The drying temperature is 120 ℃ -130 ℃, the time is about 4 hours.