Common Problems of Fireproof TPE Raw Materials in Injection Molding Process
Source：德創化工Time：2020-03-14Hits：2217
People who are engaged in the injection molding of fireproof TPE materials all know that if the filling performance of the product is not good during the process of forming and filling the mold cavity, the pressure will be reduced too much, the filling time will be too long, the filling will not be satisfactory, and so on, thus causing the product to have quality problems. So, what are the problems that fire-resistant TPE materials are easy to encounter in injection molding? How should it be solved? The following is a brief introduction.
Solutions to Problems Encountered in Injection Molding of Fireproof TPE Materials;
1. Viscous phenomenon
Compared with resin, the surface of soft TPE injection molded products is easier to stick. This can be achieved by lowering the molding temperature, low shear and purging the inside of the hydraulic cylinder of the molding machine with nitrogen to solve the viscosity problem on the product surface. When the molding machine is suspended, the rubber remains in the molten cavity of the molding machine for a long time and sometimes becomes sticky due to thermal aging. In addition, products used at high temperatures tend to stick. Therefore, it is necessary to reasonably select the types and amounts of stabilizers and softeners.
2, concave hole, color is different
Concave holes often occur in TPE injection products. For such products, provide model design around the product, such as gate or runner. Due to the uneven color of molded products, it is necessary to increase spiral back pressure and enhance packaging time.
3. Spillover margin
Sometimes the resin overflows from the cavity and causes burrs. At this time, should first reduce the filling quantity, reduce the pressure, shorten the heat preservation time, and pay attention to repair.
4. Trace Flow
There are different luster stripes on the surface of TPE sealing strip molded products. In general, there are three types of resin refraction molding:
(1) a narrow record strip;
(2) relatively widely spaced homogeneous stripes appear on the surface of the molded article;
(3) Heterotopic phase stripes with relatively narrow intervals appear on the surface of molded products;
5, uneven color
When the TPE handle particles and dry mixture are used as the precursor mixture of the pigment for coloring, color unevenness is likely to occur, and as a countermeasure, it is effective to increase the spiral back pressure and strengthen the kneading of the filler.
