Injection Molding: Two-Component Process
It can easily be seen that all the processes so far discussed are based on one component, i.e. the IF’s have cores and skins made from the same polymer. At the same time, however, injection molding does enable two-component integral foams to be fabricated in a single mold and in a single molding cycle. The resulting structures are referred to as sandwich-structures (not to be confused with the multi-layered sandwich panels mentioned in Chapter 1), two-component foams (TCF’s), or combined IF’s. They are characterized by the fact that their cores and skins are made of different polymers. To fabricate these materials, two compositions based on different polymers are used. One is designed for the surface and has no BA, while the second is compounded for the foamed core with a uniform (non-integral) cellular structure, and contains a BA (Fig. 7.1) 1).
KeywordsInjection Molding Core Material Mold Cavity Foam Core Outer Skin
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