| 摘要 |
<p>An advanced structural foam molding technology for improving the dispersion of the blowing agent in the polymer matrix has been invented. This technological innovation is an improvement on the well-known existing low-pressure structural foam moldi ng technology based on the preplasticating-type (so called piggy-bag) injection - molding machines. By introducing means for continuing the polymer matrix melt flow stream, preferably an additional accumulator and a gear pump, the processing conditions become more consistent to disperse the injected gas more uniformly in the polymer matrix. By using this technology, the structural foams have a smaller cell size, a more uniform cell structure, a larger void fraction (i.e., more material saving), less surface swirl, and less weld line contrast.</p> |
