POM F30-03三菱

Mitsubishi Engineering-Plastics Corp    POM F30-03三菱属于低粘度共聚物材料

The water absorption of Saigang material is not high, so the POM material packed with aluminium foil moisture-proof bag can be directly used for injection moulding in principle, but for products with high appearance requirements, it is better to dry before moulding. Because the drying treatment can improve the surface gloss of the products, reduce the appearance of scale, gas marks and other undesirable phenomena. For POM material which is opened and placed for a certain period of time, it will absorb moisture, so it must be dried and then used for moulding. Otherwise, there will be more scale in injection moulding, or the appearance of products will be bad because of craze. When POM is injected, in order to achieve better product appearance and reduce scale, the moisture content of raw materials should not exceed 0.1%. Higher drying temperature can shorten the time required for resin drying, but because the surface of POM products is easily oxidized and yellowed by excessive temperature, it is better to adopt milder drying conditions. The drying temperature of homopolymer POM is 80 ~ 90 C and the drying time is 2 ~ 4 h. The copolymer POM can be dried at 90-100 C for 2-4 H. The difference in drying is that the moisture absorption of copolymer formaldehyde is lower than that of homopolymer formaldehyde, and its thermal stability is better, so it is baked at high temperature.

When POM plastic material is processed, the temperature of barrel is too high, the thermal stability of POM is poor, the temperature is too high or the time is too long, all of which will cause decomposition, resulting in the decline of product performance, especially when the temperature exceeds 250 C, the decomposition speed will be accelerated, and the formaldehyde gas which strongly stimulates the eyes will spill over. In serious cases, the product will produce bubbles or discoloration. Moreover, because POM is a shear-sensitive polymer, the melt fluidity above melting point is not obvious to temperature change, but sensitive to shear rate. Therefore, the effect of improving the fluidity of POM only by increasing the temperature of POM is limited. When forming thin-walled products, it is generally recommended to use POM grade with higher melt flow rate. The melting temperature of homopolymer POM is 175 C. The temperature of resin can be set between 190 and 200 C, because the melting temperature of homopolymer POM should be taken into account to set a higher temperature and to prevent its thermal decomposition as much as possible. The melting temperature of copolymer POM is 165 C. Because the processing window is relatively wide, the resin temperature can be set at 180 ~ 200 C in injection moulding.


Resin Description: Whether homopolymer POM or copolymer POM, when moulding thin-walled or multi-cavity moulding products, faster injection speed should be adopted. This is because the injection moulding of such parts requires the system to have good fluidity. As mentioned earlier, POM melt belongs to shear-sensitive polymer. To increase its flowability, it can be achieved by increasing injection speed. At the same time, in the above applications, the cooling rate of POM crystallization will be very fast, and surface defects such as wrinkles, speckles and weld marks will easily occur on the products. Therefore, it is necessary to improve the injection speed. When moulding products with large wall thickness, a slightly slower injection speed can be used to prevent the gas wrapped in the material from effectively discharging and producing holes due to the rapid injection speed. Relatively speaking, the injection rate of homopolymer POM is higher than that of copolymer POM.