The causes and solutions of tpe injection molding overmolding glue can not stick
tpe injection molding overmolding material is usually the use of soft plastic (TPE, TPR) through secondary injection molding overmolding hard plastic (PP, PS, ABS, PA, PC, PE, etc.), the surface of hard plastic products covered with a layer of soft plastic, improve the beauty of the product, non-slip to improve grip. But in the process of wrapping often appear sticky phenomenon, how do we remedy it, I will give you the following 3 points of analysis.
Injection molding glue can not stick, first of all, we start with the simplest way to troubleshoot, . Surface cleaning of hard plastic products, the surface of the product has oil, dust, etc., before molding should be done to clean treatment. The mold sprayed release agent, will seriously affect the TPE, TPR package glue. The mold should be cleaned before molding. The TPE material may contain water, the presence of water may lead to the hydrolysis of some TPE material at high temperature, and bring unfavorable bonding effect to some plastic overmolding.
Plastic parts overmolding method
First of all, the injection temperature is different for each type of plastic injection molding material. The temperature of PP is between 170-200 degrees, but the hardness of PA is much higher, 210-250 degrees, or even higher. Low injection temperature directly affects the effect of overmolding. Low mold temperature will lead to low surface temperature of hard plastic parts put in the mold, and the TPE melt entering the mold cavity will be exposed to low mold temperature, which will also reduce the melt temperature and fluidity.
The temperature of hard products also affects the effect of overmolding. For hard plastic parts such as nylon, using secondary injection, due to the low temperature of the surface of the plastic parts, TPE/TPR melt in contact with it, will also lose part of the temperature, resulting in a decrease in melt temperature and fluidity, which is not conducive to filling and bonding. Two-color injection molding, there is no need to consider this factor.
TPE, TPR material liquidity is poor, for some thin-walled or complex structure of the product, the melt filling will be slow, the same will lead to insufficient melt temperature, affecting the bonding. Plastic injection molding material to bond with hard plastic effect, the first two materials need to have good compatibility. TPE, TPR and plastic polarity difference is large, then say that the package of things will not talk, this will need to coordinate with the TPE manufacturer to provide a suitable package of TPE \ TPR grade.
TPE injection molding overmolded material appears to wrap sticky, summed up we are from the external factors: the surface of the product clean, the material has moisture; process: injection temperature, mold temperature, into the rubber mouth design, overmolded thickness; raw materials: the compatibility of the two, fluidity, etc.. As long as we analyze all these thoroughly, secondary injection molding is not a difficult problem, any injection molding problems can consult the sales representative of TPE raw material manufacturer.
