Abstract: In foamable polystyrene resin particles that are obtained by granulating a polystyrene resin containing a flame retardant and a foaming agent, the flame retardant has a bromine atom in a molecule, contains less than 70% by mass of bromine, has a benzene ring in a molecule, and has a 5% by mass decomposition temperature in a range of from 200° C. to 300° C. the flame retardant is the sole source of bromine in the foamable polystyrene resin particles, a ratio (B:A) between (A) a by mass of the flame retardant contained in the total foamable polystyrene resin particles and (B) a % by mass of the flame retardant contained in the surface of the resin particles is in a range of from 0.8:1 to 1.2:1, and the amount of the flame retardant added is in a range of from 0.5% by mass to 5.0% by mass, based on 100 parts by mass of the resin fraction in the foamable polystyrene resin particles.

Abstract: In foamable polystyrene resin particles that are obtained by granulating a polystyrene resin containing a flame retardant and a foaming agent, the flame retardant has a bromine atom in a molecule, contains less than 70% by mass of bromine, has a benzene ring in a molecule, and has a 5% by mass decomposition temperature in a range of from 200° C. to 300° C. the flame retardant is the sole source of bromine in the foamable polystyrene resin particles, a ratio (B:A) between (A) a by mass of the flame retardant contained in the total foamable polystyrene resin particles and (B) a % by mass of the flame retardant contained in the surface of the resin particles is in a range of from 0.8:1 to 1.2:1, and the amount of the flame retardant added is in a range of from 0.5% by mass to 5.0% by mass, based on 100 parts by mass of the resin fraction in the foamable polystyrene resin particles.

Abstract: In foamable polystyrene resin particles that are obtained by granulating a polystyrene resin containing a flame retardant and a foaming agent, the flame retardant has a bromine atom in a molecule, contains less than 70% by mass of bromine, has a benzene ring in a molecule, and has a 5% by mass decomposition temperature in a range of from 200° C. to 300° C., the flame retardant is the sole source of bromine in the foamable polystyrene resin particles, a ratio (B/A) between (A) a % by mass of the flame retardant contained in the total foamable polystyrene resin particles and (B) a % by mass of the flame retardant contained in the surface of the resin particles is in a range of from 0.8/1 to 1.2/1, and the amount of the flame retardant added is in a range of from 0.5% by mass to 5.0% by mass, based on 100 parts by mass of the resin fraction in the foamable polystyrene resin particles.

Abstract: A blowing agent is infiltrated into polystyrene resin particles dispersed in an aqueous suspension. Before or during infiltration, a flame retardant solution obtained by dissolving 33-1,000 parts by weight of a powdery flame retardant and 20-200 parts by weight of a flame retardant aid having a 1-hour half-life temperature of 100-250° C. in 100 parts by weight of a plasticizer is supplied to the aqueous suspension to infiltrate the flame retardant and the flame retardant aid into the particles, producing expandable polystyrene resin particles. By dissolving the flame retardant, which doesn't accumulate in the living body and has satisfactory handleability, in a plasticizer, the flame retardant can be evenly infiltrated into resin particles. Consequently, expansion of the expandable particles doesn't result in unevenness of cell density and the particles have excellent heat-fusibility to one another during molding, and molded foam having excellent flame retardancy and heat resistance can be obtained.

Abstract: 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.

Abstract: In foamable polystyrene resin particles that are obtained by granulating a polystyrene resin containing a flame retardant and a foaming agent, the flame retardant has a bromine atom in a molecule, contains less than 70% by mass of bromine, has a benzene ring in a molecule, and has a 5% by mass decomposition temperature in a range of from 200° C. to 300° C., and a ratio (B/A) between (A) the amount of the flame retardant contained in the total foamable polystyrene resin particles and (B) the amount of the flame retardant contained in the surface of the resin particles is in a range of from 0.8 to 1.2. By pre-foaming the foamable polystyrene resin particles and then foaming the particles in a mold, a polystyrene resin foam-molded article having flame retardancy is obtained.

Abstract: [Object] The object of the present invention is to provide a molded foam product in which a flame retardant having no accumulating property in a living body and satisfactory handling property during the production process is dissolved in a plasticizer so that the flame retardant can be uniformly impregnated into resin particles, and which shows excellent heat-fusibility between the particles during molding without resulting in uneven cell density upon expanding, and has excellent flame retardancy and heat resistance.

Abstract: 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.