초록 ▼

Using a new molded foaming apparatus wherein chambers 13 and 14 , independent from a cavity 4 , are formed at the rear sides of a set of dies 2 and 3 for molding a molded foam product, so as to supply such utility fluid as air and steam to the cavity 4 through first openings 30 independently from th

Using a new molded foaming apparatus wherein chambers 13 and 14 , independent from a cavity 4 , are formed at the rear sides of a set of dies 2 and 3 for molding a molded foam product, so as to supply such utility fluid as air and steam to the cavity 4 through first openings 30 independently from the chambers 13 and 14 , various problems created when forming vent holes are fundamentally solved, and at the same time dispersion of filling density to be caused by not forming vent holes is prevented by supplying the material beads to the cavity 4 while maintaining the pressure in the cavity 4 at a predetermined minus pressure with respect to the pressure in the material tank using the first openings 30.

대표청구항 ▼

1. A method for die-expanded molded foaming of synthetic resin comprising the steps of:filling material beads in a cavity enclosed within a pair of dies with chambers disposed on the rear sides respectively; heating, expanding and fusing the material beads to be a molded foam body; and cooling, rele

1. A method for die-expanded molded foaming of synthetic resin comprising the steps of:filling material beads in a cavity enclosed within a pair of dies with chambers disposed on the rear sides respectively; heating, expanding and fusing the material beads to be a molded foam body; and cooling, releasing and taking out the molded foam body from the dies, wherein the following processes are included:a) a die closing process where the dies are closed to form said cavity air tightly isolated from said chambers, and to form utility passages independent from the chambers and directly connected to the cavity;b) a filling process where the material beads are supplied and filled into the cavity from a material tank while maintaining the pressure in the cavity at a predetermined pressure lower than the pressure in said material tank, at the same time heating steam is supplied to said chambers so as to heat the entire dies around the chambers to a temperature where the material beads do not expand;c) an internal heating process where heating steam having a temperature less than the fusing temperature of the material beads is supplied to said cavity through said utility passages so as to heat the filled material beads, and at the same time, form condensed water on the faces of the dies enclosing the cavity; andd) a fusion heating process where heating steam having a temperature at the fusion temperature of the material beads or higher is supplied to said chamber, so as to evaporate the condensed water in said cavity and to progress expansion and fusion of the material beads. 2. A method for die-expanded molded foaming of synthetic resin, wherein a cavity is formed enclosed with a pair of dies with chambers disposed on the rear sides respectively, and is air tightly isolated from said chambers, then the material beads are supplied to said cavity while maintaining the pressure in said cavity to a predetermined pressure lower than the pressure in a material tank; andwherein heating conditions for said chambers and said cavity are controlled, thereby the material beads filled in the cavity are heated, expanded and fused while controlling the internal fusion rate at will with maintaining the surface property of the molded foam product, and said heating conditions in said cavity are controlled through utility passages means independent from said chambers. 3. The method for die-expanded molded foam of synthetic resin according to claim 1 or 2, wherein the material beads are supplied to the cavity while maintaining the pressure in said material tank at a pressure from atmosphere pressure to 5.0 kg/cm 2 . 4. The method for die-expanded molded foaming of synthetic resin according to claim 3, wherein the pressure in said cavity is maintained at a pressure of at least atmospheric pressure and lower than the pressure in the material tank by 0.5 kg/cm 2 or less. 5. The method for die-expanded molded foaming of synthetic resin according to claim 3, wherein the pressure in said cavity is maintained at a reduced pressure from atmospheric pressure to minus 1.0 kg/cm 2 . 6. The method for die-expanded molded foaming of synthetic resin according to claim 1 or 2, wherein the pressure in said cavity is from 5.0 kg/cm 2 to minus 1.0 kg/cm 2 . 7. The method for die-expanded molded foaming of synthetic resin according to claim 1,wherein in said die closing process, said utility passages are slit shaped openings opening to the cavity formed along an accessory part to be attached to at least one of the dies and/or formed along the joint of said pair of dies and being of a width not more than the outer diameter size of a material bead to be filled, and connect to passages to external utility pipes. 8. The method for die-expanded molded foaming of synthetic resin according to claim 7, wherein said accessory part is a filling unit of material beads or an ejector pin. 9. The method for die-expanded molded foaming of synthetic resin according to claim 1,wherein a returning-to-atmosphere process for releasing the inside of said cavity from the pressurized state to an atmospheric pressure state or an exhaust process for reducing pressure inside said cavity to exhaust internal air is added between said filling process and the internal heating process. 10. The method for die-expanded molded foaming of synthetic resin according to claim 2,wherein the internal fusion rate is controlled at will with maintaining the surface property of the molded foam product while independently controlling the heating conditions for the pair of chambers and the cavity. 11. The method for die-expanded molded foaming of synthetic resin according to claim 10,wherein the steam pressure and time are controlled as heating conditions. 12. The method for die-expanded molded foaming of synthetic resin according to claim 1 or 2, wherein the material beads are polyolefin synthetic resin material heating the surface and the inside under the same heating conditions. 13. A method for filling material beads from a material tank to a cavity comprised of a set of dies,wherein the cavity is formed enclosed with a pair of dies with chambers disposed on the rear sides respectively, and is air tightly isolated from said chambers, then the material beads are supplied to said cavity while maintaining the pressure in the material tank at a pressure from atmospheric pressure to 5.0 kg/cm 2 , and, through utility passage means independent from said chambers, maintaining the pressure in the cavity at a pressure of at least atmospheric pressure and less than the pressure in the material tank by 0.5 kg/cm 2 or less.