EXPANDABLE POLYSTYRENE RESIN BEADS, PROCESS FOR PRODUCTION THEREOF AND EXPANDED MOLDINGS

• Main Authors: CHINOMI, RYOSUKE, TARUMOTO, HIROYUKI, SAITOU, YOSHIFUMI
• Format: Patent
• Language: English; French; German
• Published: 20.10.2010
• Subjects: AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F,C08G; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING; CHEMISTRY; COMPOSITIONS BASED THEREON; COMPOSITIONS OF MACROMOLECULAR COMPOUNDS; GENERAL PROCESSES OF COMPOUNDING; INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS; MAKING GRANULES OR PREFORMS; METALLURGY; ORGANIC MACROMOLECULAR COMPOUNDS; PERFORMING OPERATIONS; PREPARATION OR PRETREATMENT OF THE MATERIAL TO BESHAPED; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIALCONTAINING PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDEDFOR; SHAPING OR JOINING OF PLASTICS; THEIR PREPARATION OR CHEMICAL WORKING-UP; TRANSPORTING; WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE, IN GENERAL; WORKING-UP

There are provided expandable polystyrene resin particles formed by granulating a polystyrene resin containing an expanding agent, wherein the weight-average molecular weight Mw of the polystyrene resin is in the range of 120,000 to 270,000, and the expanding agent contains, as an essential component, pentane at a proportion of 3 to 8 parts by mass based on 100 parts by mass of the polystyrene resin, while the composition of the pentane is in the range of isopentane:normal pentane = 10:90 to 80:20 by mass ratio. These expandable polystyrene resin particles can utilize a recycled raw material, and can produce a molded foam product having sufficient mechanical strength, while the expandable polystyrene resin particles have a long bead life and excellent low pressure moldability.