Abstract: Injection moldings have excellent surface gloss and freedom from sink marks are obtained using a pressurized mold and molding composition containing a volatile fluid foaming agent, a thermally decomposable foaming agent and a finely divided nucleating agent.

Abstract: A compression stressed liner for refrigeration equipment and a method of stressing the same is disclosed. The effective life span of refrigeration equipment liners can be significantly increased by compression stressing. Stressing liners in compression before or during assembly of refrigeration equipment is accomplished by bending the liners, molding the liners to form a shallow arc in one direction of its structure or shrinking the liners and then securely attaching the same. Compression stressed liners counteract localized tensile stresses that normally develop because of shrinking of the liners during use at temperatures substantially below assembly temperatures. Compression stressing of liners also reduces the size of or eliminates foramina on the exposed surfaces of the liners, normally increased in size by the tensile stresses, thus decreasing chemical penetration and attack of liners.