PA as one of the world's three major engineering materials, has a strong application type, and with the continuous development of science and technology, PA in our lives can be described as ubiquitous. However, due to its own inherent shortcomings, but also limit its application in some areas, therefore, modified nylon nylon applications as the main direction of development.
Top light Xiaobian today to introduce, modified nylon in the injection process of application of knowledge.
PA modification methods are:
1. Glass fiber reinforced PA PA added 30% glass fiber, PA mechanical properties, dimensional stability, heat resistance, anti-aging properties have significantly improved fatigue strength is not enhanced 2.5 times. Glass fiber reinforced PA molding process is not the same as the enhanced, but because the flow worse than before the increase, so the injection pressure and injection rate should be appropriately increased, the barrel temperature increased by 10-40 ℃. As the glass fiber in the injection molding process will be along the flow direction, causing the mechanical properties and shrinkage increased in the direction of orientation, resulting in warping deformation of products, therefore, the mold design, the gate location, shape to be reasonable, process can be improved Mold temperature, after removing the product into the hot water to slow cooling. In addition, the greater the proportion of fiberglass, plastic injection molding machine which wear the greater the best use of bimetallic screw, barrel.
2. Flame Retardant PA Due to the addition of a flame retardant in the PA, most of the flame retardants are easily decomposed at high temperature to release acidic substances and have a corrosive effect on the metal. Therefore, the plasticizing components (screw, Rubber ring, plastic gasket, flange, etc.) need to be hard chrome plated. Process, try to control the barrel temperature can not be too high, the injection speed can not be too fast, in order to avoid the plastic material temperature is too high and cause decomposition products discoloration and mechanical properties decline.
3. Transparent PA has good tensile strength, impact resistance, rigidity, abrasion resistance, chemical resistance, surface hardness and other properties, high transmittance, similar to optical glass, processing temperature is 300 - 315 ℃, forming Processing, the need to strictly control the barrel temperature, the melt temperature is too high will lead to product degradation due to degradation, the temperature is too low due to poor plasticization affect the transparency of products. Try to take the mold temperature is lower, the mold temperature is high and the transparency of the product will be reduced. 4. Weatherability PA PA added carbon black and other UV-absorbing additives, these PA on the self-lubricating and metal wear greatly enhanced, molding processing will affect the cutting and wear parts. Therefore, the need to use strong feed capacity and high wear resistance of the screw, barrel, over the plastic head, a plastic ring, plastic gasket combination.
