Manufacturing method and manufacturing device for foam molded article

A method for producing a foam-molded product by using a producing apparatus including a plasticizing cylinder provided with a plasticizing screw which is rotatable inside the plasticizing cylinder, wherein the plasticizing cylinder comprises:

• a plasticization zone in which a thermoplastic resin is plasticized and melt into a molten resin, a starvation zone in which the molten resin is allowed to be in a starved state, and a recompression zone in which the molten resin is compressed to increase pressure of the molten resin, wherein the plasticization zone, the starvation zone, and the recompression zone are arranged in this order from an upstream side in a flowing direction of the resin, and wherein the plasticizing cylinder further comprises an introducing port via which a physical foaming agent is introduced into the starvation zone, the method comprising:
• plasticizing and melting the thermoplastic resin into the molten resin in the plasticization zone;
• introducing a pressurized fluid containing the physical foaming agent having a fixed pressure into the starvation zone;
• allowing the molten resin to be in the starved state in the starvation zone;
• bringing the molten resin in the starved state into contact with the pressurized fluid having the fixed pressure in the starvation zone;
• compressing the molten resin in the starved state that is in contact with the pressurized fluid to increase the pressure of the molten resin in the recompression zone;
• and
• molding the pressure-increased molten resin into the foam-molded product,
• wherein at least one pressure boosting part is provided in the starvation zone of the plasticizing cylinder.