High PC transparency, good impact toughness, creep resistance, weather resistance, high temperature resistance TEL The Elastic Body Colour Masterbatch produced by Caijian Plastic Pigment company,It is a carrier with elastomer material as color masterbatch, which has good compatibility with elastic body and good dispersion, does not reduce the physical and mechanical strength of the elastomer, anti aging, acid and alkali resistance. It is applied to animal ear tag, door and window seal, advanced electric wire, high grade sign board and so on. Elastic Body Colour Masterbatch Granules Elastic Body Colour Masterbatch Granules Cai Jian Plastic Product Co., Ltd. , http://www.caijianmasterbatch.com
Excellent PC performance, high transparency, good impact toughness, creep resistance, wide temperature range, PC process characteristics: melt viscosity is less sensitive to shear rate, and sensitive to temperature, no obvious melting point, The melt has a high viscosity, and the resin is easily hydrolyzed at a high temperature, and the product is easily cracked. In view of these characteristics, we must pay special attention to the difference: to increase the fluidity of the melt, it is not to increase the injection pressure but to increase the injection temperature. It is required that the flow path and gate of the mold are short and thick to reduce the pressure loss of the fluid, and at the same time, a higher injection pressure. The resin should be thoroughly dried before the molding process to control the water content to less than 0.02%. In addition, the PC should be insulated during the processing to prevent re-absorption. Not only reasonable product design is required, but also the molding process should be properly mastered, such as increasing the mold temperature and post-processing the product to reduce or eliminate internal stress. The process parameters are adjusted in time according to the different conditions of the product.
Let's talk about the molding process
1. The injection temperature must be integrated with the shape, size and mold structure of the product. Only after considering the performance and requirements of the product can be made. Generally, the temperature is between 270 and 320 °C in the molding. When the material temperature is too high, such as more than 340 °C, the PC will decompose, the color of the product will become darker, and defects such as silver, dark stripes, black spots and bubbles will appear on the surface. At the same time, physical and mechanical properties also dropped significantly.
2, the injection pressure on the physical and mechanical properties of PC products, internal stress, molding shrinkage, etc. have a certain impact on the appearance and release of the product, too low or too high injection pressure will make the product appear Some defects, generally injection pressure control between 80-120MPa, for thin-walled, long-flow, complex shape, smaller gates, in order to overcome the resistance of the melt flow, in order to fill the cavity in time, select a higher Injection pressure (120-145 MPa). Thereby a complete and smooth surface product is obtained.
3, holding pressure and holding time The pressure holding pressure and the length of dwelling time have a greater impact on the internal stress of PC products, the holding pressure is too small, the shrinking effect is small, easy to appear vacuum bubble or surface shrinkage Concave, the pressure is too large, and it is easy to produce large internal stress around the gate. In actual processing, it is often solved by high material temperature and low pressure. The choice of holding time should be determined according to the thickness of the product, the size of the gate, the temperature of the mold, etc. Generally, the small and thin products do not require a long holding time. On the contrary, the thick and thick products should have a longer holding time. The length of the holding time can be determined by the test of the gate sealing time.
4. The injection speed has no obvious influence on the performance of PC products. Except for thin wall, small gate, deep hole and long process products, it is generally processed by medium or slow speed, preferably multi-stage injection, generally slow. - Fast-slow multi-stage injection.
5, the mold temperature is generally controlled at 80-100 ° C, for complex shapes, thinner, higher requirements, can also be increased to 100-120 ° C, but can not exceed the mold heat distortion temperature.
6, screw speed and back pressure due to PC melt viscosity is greater, from the beneficial plasticization, favorable exhaust, beneficial to the maintenance of the plastic machine, to prevent excessive screw load, the screw speed requirements can not be too high, generally controlled at 30 -60r/min is preferred, and the back pressure control is preferably between 10-15% of the injection pressure.
7. PC should strictly control the use of release agent during the injection molding process. At the same time, the use of recycled materials should not exceed three times, and the usage should be about 20%.
Plastic machine requirements for the production of PC products: the maximum injection volume (including runners, gates, etc.) of the product should be no more than 70-80% of the nominal injection volume. The screw should be a single-thread thread with a pitch, with a gradient of the check ring. The compression type screw has a length to diameter ratio L/D of 15-20 and a geometric compression ratio C/R of 2-3.
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High PC transparency, good impact toughness, creep resistance, weather resistance, high temperature resistance