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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