Process for production of expansion-molded articles in a mold of linear low density polyethylene resins

Abstract

Abstract The present invention provides a process for production of expansion-molded articles in a mold of a linear low density polyethylene resin which comprises compressing pre-expanded linear low density polyethylene resin beads having two melting points when measured by differential scanning calorimetry and, when the melting point at a low temperature side and the melting point at a high temperature side are designated T ML and T MH respectively, between said two melting points and the peak fusion area at said T ML is designated A L and the peak fusion area at said T MH is designated A H satisfying: 5%≦A.sub.H /A.sub.L ≦80% under a gaseous pressure, filling with said compressed beads a mold capable of closing but incapable of sealing, then venting from said mold and, heating and fusing with steam in such a state that a compressive rate of said pre-expanded beads immediately before said heating with steam to the original pre-expanded beads is maintained to 5 to 60% thereby to produce the molded article in the shape of said mold. According to the present invention, the molded articles of linear low density polyethylene having a minimized dimensional shrinkage rate (good dimensional accuracy) and excellent fusion rate and surface appearance can be produced in high productivity.

Inventors

• 👤 Hirofumi Maeda

Bibliographic Details