2015年1月29日星期四

Commonly used plastic raw materials POM

Polyacetal (POM) POM called "Race of steel", is a crystalline plastic, main properties are as follows:

1 POM is white plastic and shiny.

2 has good mechanical properties, hardness, high stiffness, good impact resistance and has excellent abrasion resistance and self-lubricating properties.

3 good resistance to organic solvents, stable performance.

4 after forming size is relatively stable, less affected by humidity. POM molding process to understand
1 POM small (smaller absorption rate <0.5%) moisture, generally does not dry before molding or short dry.

2 molding temperature range is narrow, poor thermal stability above 250 decomposition of formaldehyde monomer (melt darken) it alone to raise the temperature to improve liquidity and no harmful effect. Normal beer plastic feeding tube should adopt a lower temperature and a shorter residence time and increase the injection pressure can improve mobility and the quality of the product surface melt (melt flow rate of shear sensitive) temperature parameters: Before feeding tube 190-210 , the feeding tube 180-205 , after feeding tube 150-175 pressure parameters: the injection pressure is about 100Mpa, back pressure 0.5Mpa.

3 mold temperature control at 80-100 is appropriate (usually run hot oil)


4. POM cooling shrinkage large (2 to 2.5%) prone beer plastic "shrink", it must be used to extend the holding time to feeding.

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