Provided is a resin for foam molding excellent in foam molding property and low-temperature impact resistance. According to the present invention, provided is a resin for foam molding including a component A, a component B and a component C. The component A is a long-chain branched homopolypropylene, the component B is a long-chain branched block polypropylene, the component C is a polyethylene-based elastomer, and when a total of the components A to C is 100 parts by mass, content of the component A is 20 to 70 parts by mass, content of the component B is 20 to 70 parts by mass, and content of the component C is 1 to 20 parts by mass.

A method of preparation of a cardo polyetherketone structural foam material, including the following steps: 1) performing a mould pressing on a cardo polyetherketone resin by a high-temperature vulcanizing machine to prepare a foaming billet; 2) placing the foaming billet in a foaming cavity of a mould-pressing machine, performing a penetration and a swelling by introducing a supercritical fluid to achieve diffusion equilibrium, forming a polymer-supercritical fluid homogeneous solution, and 3) making the polymer-supercritical fluid homogeneous solution supersaturated through a sudden release of the inner pressure of the system, thereby inducing nucleation and foaming, and finally forming a structural foam having a closed pore structure with a uniform pore size and an adjustable pore density. The production process of the present invention is clean, environmentally friendly, and has relatively high efficiency. The obtained structural foam has good mechanical properties.

A method of preparation of a cardo polyetherketone structural foam material, including the following steps: 1) performing a mould pressing on a cardo polyetherketone resin by a high-temperature vulcanizing machine to prepare a foaming billet; 2) placing the foaming billet in a foaming cavity of a mould-pressing machine, performing a penetration and a swelling by introducing a supercritical fluid to achieve diffusion equilibrium, forming a polymer-supercritical fluid homogeneous solution, and 3) making the polymer-supercritical fluid homogeneous solution supersaturated through a sudden release of the inner pressure of the system, thereby inducing nucleation and foaming, and finally forming a structural foam having a closed pore structure with a uniform pore size and an adjustable pore density. The production process of the present invention is clean, environmentally friendly, and has relatively high efficiency. The obtained structural foam has good mechanical properties.

A method for producing polyamide-based resin multi-stage expanded beads includes an internal pressure applying step of placing polyamide-based resin expanded beads in a pressure-resistant container, impregnating the polyamide-based resin expanded beads with a physical blowing agent in the pressure-resistant container to apply internal pressure higher than atmospheric pressure; and a heating and foaming step of heating and expanding the polyamide-based resin expanded beads to which internal pressure is applied obtained in the internal pressure applying step to obtain polyamide-based resin multi-stage expanded beads having apparent density lower than that of polyamide-based resin expanded beads used in the internal pressure applying step, in the internal pressure applying step, polyamide-based resin expanded beads in a wet state having a water content of 1% or more being impregnated with the physical blowing agent at a temperature higher than change-point temperature of storage modulus of the polyamide-based resin expanded beads in a wet state.

Pre-expanded polypropylene-based resin particles include a polypropylene-based resin. The polypropylene-based resin satisfies tan 0.32V+0.1, where tan represents a loss tangent at an angular frequency of 0.1 rad/s in dynamic viscoelastic behavior measurement at 200 C. and V represents a melt fracture take-up speed (m/min) at 200 C.

Pre-expanded polypropylene-based resin particles include a polypropylene-based resin. The polypropylene-based resin satisfies tan 0.32V+0.1, where tan represents a loss tangent at an angular frequency of 0.1 rad/s in dynamic viscoelastic behavior measurement at 200 C. and V represents a melt fracture take-up speed (m/min) at 200 C.

Provided is a method for producing a resin molded article including an introducing step of introducing a plurality of resin foam particles and a heat medium substance into a forming mold, and a molding step of, after the introducing step, heating the forming mold to a temperature at which the heat medium substance can be vaporized, thereby obtaining a resin molded article including the plurality of resin foam particles.

A method for manufacturing a foam molded body which can allow the foam resin sheet to follow the shape of the cavity of the mold with high accuracy even when the thickness of the foam resin sheet is thick. The method includes an arranging step to arrange one sheet of a foam resin sheet between first and second molds, the foam resin sheet being formed by extruding and dangling a molten foam resin from a slit; and an expanding step to expand the foam resin sheet by subjecting the foam resin sheet to a reduced pressure suction.

A method for manufacturing a foam molded body which can allow the foam resin sheet to follow the shape of the cavity of the mold with high accuracy even when the thickness of the foam resin sheet is thick. The method includes an arranging step to arrange one sheet of a foam resin sheet between first and second molds, the foam resin sheet being formed by extruding and dangling a molten foam resin from a slit; and an expanding step to expand the foam resin sheet by subjecting the foam resin sheet to a reduced pressure suction.

A method and an extrusion device for producing a foamed body. A plastics melt is produced inside the casing of a first extruder. The plastics melt is conveyed to an outlet die of a second extruder. The conveyed plastics melt has a foaming agent and expands after being fed through the outlet die. Before the plastics melt is fed through the outlet die, variations in temperature between different radial positions over the cross-section of the plastics melt are reduced by an extruder screw device which has a number of screw spindles distributed around the periphery. The plastics melt which is thus thermally homogeneous is fed through the outlet die.