Forming characteristics of modified plastic
What are the main process characteristics of modified plastics?
1.Nylon is susceptible to moisture.
In the atmosphere, the equilibrium water absorption rate of PA is 3.5%, 2.5% of PA66, 1.5% of PA610 and 0.8% of PA1010.
The water content of nylon has great influence on its mechanical properties. In the molten state, the presence of water will cause the hydrolysis of nylon resulting in molecular weight
To reduce the mechanical properties of the products, but also in the molding of the surface of the products appear bubbles, silver and markings and other defects. So it must be full before forming Dry.
2. Nylon melt has low viscosity and high fluidity, and the nozzle will produce "casting" phenomenon. Waste raw materials, contaminate nozzles. If you use a screw injection
Machine molding, injection, melt will appear between the screw and the cylinder wall countercurrent, so that the injection is not allowed, so, nylon in screw injection machine molding, the end of the screw must be installed in the reverse ring.
3. Nylon is a crystalline polymer. The melting point is obvious, and higher, so nylon needs to be formed at a higher temperature
Poor thermal stability, easy to decompose. Therefore, the technological conditions must be strictly controlled.
4 nylon molding shrinkage rate is large,
for the manufacture of high precision products, mold design should be based on the test to determine its size, molding process should be strictly controlled.