Anisotropic shrinkage of injection-molded rubber

✍ Scribed by Kunihiko Nakashima; Hiroshi Fukuta; Minoru Mineki

• Book ID: 102732989
• Publisher: John Wiley and Sons
• Year: 1973
• Tongue: English
• Weight: 796 KB
• Volume: 17
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/app.1973.070170309

✦ Synopsis

Abstract

The anisotropic characteristics of injection‐molded flat rubber sheets were investigated. The shrinkage and mechanical properties were measured in two directions: parallel and perpendicular to the flow direction. The results showed that (1) the shrinkage in the parallel direction is larger than that in the perpendicular direction, (2) such anisotropic shrinkage increases with the increase of vulcanization temperature and flow distance, (3) similar anisotropy was also noticed in 300% modulus, tensile strength, and elongation. Two kinds of orientation, “shear orientation” and “expanded orientation,” were observed. The former occurs by plug flow, and the latter by the expansion of the materials. The shrinkage was independent of the expanded orientation but was strongly associated with the shear orientation, while the mechanical properties were affected by the expanded orientation.