Abstract: A die plate for a die block can have a coat-hanger-shaped flow path for extruding a molten foamable thermoplastic resin in a form of a sheet. The die plate can be on a downstream side of the coat-hanger-shaped flow path to make a flow rate of the molten foamable thermoplastic resin uniform in a width direction. The die plate can have a multiplicity of delivery apertures. The delivery apertures in opposite side regions can have a diameter greater than a diameter which the delivery apertures in a center region have. A die unit can include a die block, which has a multiple bifurcated manifold terminating in plural coat-hanger-shaped flow paths at downward ends thereof, and a like plural number of similar die plates as described above. A process for producing a wide thermoplastic resin foam can use the die unit.

Abstract: To provide a foam board of a polyolefin resin which has an excellent heat insulating property and sound absorption property, of which a product can be material-recycled and which can continuously be produced at a low cost; a method for producing a foam board, which comprises extrusion-foaming by ejecting a mixture of a polyolefin resin composition containing a linear polypropylene resin having a melt tension of from 5 to 30 g at 230° C. and a foaming agent containing at least carbon dioxide in the supercritical state, by means of an extruder which has a multi-hole type die having an opening diameter of from 0.1 to 1.0 mm and the number of openings of from 50 to 5,000 at an ejection amount (V) of from 0.05 to 0.45 kg/hr per one opening in the die at a melt-extrusion temperature of from 160 to 250° C., under atmosphere at a proximal resin pressure of from 7 to 20 MPa at the openings of the die.

Abstract: An extruded polypropylene type resin foam having a high expansion ratio of at least 15 times and a closed cell ratio of at least 70% and excellent in the heat insulation property, and its production process, are provided. An extruded polypropylene type resin foam, which is produced by extrusion-foaming a polypropylene type resin composition containing a linear polypropylene type resin having a melt tension at 230° C. of from 5 to 30 g, by using a blowing agent containing at least a hydrocarbon type gas, and which has an expansion ratio of at least 15 times and a closed cell ratio of at least 70%.

Abstract: A die plate for a die block can have a coat-hanger-shaped flow path for extruding a molten foamable thermoplastic resin in a form of a sheet. The die plate can be on a downstream side of the coat-hanger-shaped flow path to make a flow rate of the molten foamable thermoplastic resin uniform in a width direction. The die plate can have a multiplicity of delivery apertures. The delivery apertures in opposite side regions can have a diameter greater than a diameter which the delivery apertures in a center region have. A die unit can include a die block, which has a multiple bifurcated manifold terminating in plural coat-hanger-shaped flow paths at downward ends thereof, and a like plural number of similar die plates as described above. A process for producing a wide thermoplastic resin foam can use the die unit.

Abstract: An extruded polypropylene type resin foam having a high expansion ratio of at least 15 times and a closed cell ratio of at least 70% and excellent in the heat insulation property, and its production process, are provided. An extruded polypropylene type resin foam, which is produced by extrusion-foaming a polypropylene type resin composition containing a linear polypropylene type resin having a melt tension at 230° C. of from 5 to 30 g, by using a blowing agent containing at least a hydrocarbon type gas, and which has an expansion ratio of at least 15 times and a closed cell ratio of at least 70%.

Abstract: To provide a foam board of a polyolefin resin which has an excellent heat insulating property and sound absorption property, of which a product can be material-recycled and which can continuously be produced at a low cost. A method for producing a foam board, which comprises extrusion-foaming by ejecting a mixture of a polyolefin resin composition containing a linear polypropylene resin having a melt tension of from 5 to 30 g at 230° C. and a foaming agent containing at least carbon dioxide in the supercritical state, by means of an extruder which has a multi-hole type die having an opening diameter of from 0.1 to 1.0 mm and the number of openings of from 50 to 5,000 at an ejection amount (V) of from 0.05 to 0.45 kg/hr per one opening in the die at a melt-extrusion temperature of from 160 to 250° C., under atmosphere at a proximal resin pressure of from 7 to 20 MPa at the openings of the die.

Abstract: Disclosed is a process for producing a polypropylene-based resin foam by subjecting a linear polypropylene-based resin, which has a melt tension at 230° C. of from 5 to 30 g and satisfies the below-described formula (1) in which MFR stands for a melt flow rate of the linear polypropylene-based resin at 230° C. and MT stands for the melt tension at 230° C., to melt extrusion through an extruder while injecting carbon dioxide into the resulting molten resin to foam the molten resin. The process includes subjecting the extruder to temperature control such that the extruder has a temperature of from 200 to 240° C. at a position of a cylinder barrel thereof, where the carbon dioxide is to be introduced, and the cylinder barrel has a temperature of from 175 to 190° C.

Abstract: Disclosed is a die plate for a die block having a coat-hanger-shaped flow path for extruding a molten foamable thermoplastic resin in a form of a sheet. The die plate is for arrangement on a downstream side of the coat-hanger-shaped flow path to make a flow rate of the molten foamable thermoplastic resin uniform in a width direction. The die plate is provided with a multiplicity of delivery apertures. In the delivery apertures, the delivery apertures in opposite side regions have a diameter greater than a diameter which the delivery apertures in a center region have. A die unit composed of a die block, which has a multiple bifurcated manifold terminating in plural coat-hanger-shaped flow paths at downward ends thereof, and a like plural number of similar die plates as described above; a process for producing a wide thermoplastic resin foam by using the die unit; and the wide thermoplastic resin foam are also disclosed.