Can polyethylene wax be used for ABS? ABS plastic is a material used in electronic appliances and building materials. ABS plastic is used in many electronic appliances such as washing machines, televisions, refrigerators, computers, and copiers that we commonly see in life.
1. Plastic processing:
The water absorption rate of ABS is approximately 0.2%-0.8%. For general-grade ABS, dry it in an oven at 80-85°C for 2-4 hours or use drying material at 80°C for 1-2 hours before processing. Hours. For heat-resistant ABS containing PC components, the drying temperature should be appropriately raised to 100°C. The specific drying time can be determined by extruding it into the air.
The proportion of recycled materials cannot exceed 30%, and recycled materials cannot be used in electroplating grade ABS.
2. Injection molding machine selection:
Ramada’s standard injection molding machine can be used (screw diameter ratio 20:1, compression ratio greater than 2, injection pressure greater than 1500bar). If you use colored grains or the appearance of the product requires high material, you can choose a smaller diameter.
Determine according to 4700-6200t/m2, the specific requirements shall be determined according to the plastic grade and product requirements.
3. Mold and gate design:
The mold temperature can be set to 60-65℃. The flow channel diameter is 6-8mm. The gate width is about 3mm, the thickness is the same as the product, and the gate length should be less than 1mm. The exhaust hole is 4-6mm wide and 0.025-0.05mm thick.
4. Injection speed:
Use slow speed for fire-proof grade and fast speed for heat-resistant grade. If the product surface requirements are high, high-speed and multi-stage injection molding injection rate control should be used.
5. Back pressure:
Generally speaking, the lower the back pressure, the better. The commonly used back pressure is 5bar. Dyes require higher back pressure to achieve uniform color mixing.
6. Detention time:
At a temperature of 265°C, the residence time of ABS in the melt barrel cannot exceed 5-6 minutes at most. The flame retardant time is shorter. If the machine needs to be shut down, the set temperature should be lowered to 100°C first, and then the melt barrel should be cleaned with general-grade ABS. The cleaned mixture should be placed in cold water to prevent further decomposition. If you need to change from other plastics to ABS materials, you must first clean the melt barrel with PS, PMMA or PE. Some ABS products have no problem when they are first demoulded, but will change color after a period of time. This may be caused by overheating or the plastic staying in the melt barrel for too long.
7. Post-processing of products:
Generally, ABS products do not require post-processing. Only electroplating-grade products need to be baked (70-80℃, 2-4 hours) to passivate surface traces. And products that require electroplating cannot use release agents before taking out the products. Pack immediately afterward.
8. Things to pay special attention to when molding:
There are several grades of ABS (especially the flame retardant grade). After plasticization, the melt has a strong adhesion to the screw surface and will decompose after a long time. When the above situation occurs, the screw homogenization section and compression pullout need to be wiped, and the screw needs to be cleaned regularly with PS, etc.
Plastic ABS is not affected by water, inorganic salts, alkali and various acids, but it is soluble in ketones, aldehydes and chlorinated hydrocarbons. It will cause stress cracking when corroded by glacial acid, vegetable oil, etc. ABS has poor weather resistance and is prone to degradation under the influence of ultraviolet light; after being exposed outdoors for half a year, the impact strength drops by half. TIANSHI New Materials, with 20 years of experience, focuses on the R&D and production of wax micropowders, including the R&D, production and application of polyethylene wax, oxidized polyethylene wax, polypropylene wax, wax emulsion and PTFE micropowder.
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