Method of production of expansion-molded article, from foamable thermoplastic resin particles and apparatus therefor
AssigneeJapan Styrene Paper Corporation
InventorsHedeki Kuwabara, Atusi Kitagawa, Masato Kanbe
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Abstract
This invention relates to a method and apparatus for improving not only the quality of the production of molded foamable thermoplastic resin particles converted into fusion-bonded materials but also the output by protecting the resin from atmospheric pressure by pressurizing the particles and heating the particles to soften the same.
Claims18
A method for producing an expansion-molded article from internally pressurized pre-foamed particles of a thermoplastic resin which comprises:
- maintaining a supply of said internally pressurized pre-foamed particles under pressure in a pressurizing tank;
- transferring a suitable portion of said pre-foamed particles, under pressure, to a pressurizing hopper and holding the transferred particles under pressure in said pressurizing hopper;
- feeding under pressure into a mold a predetermined amount of the pre-foamed particles from the pressurizing hopper;
- and
- heating the thus-filled pre-foamed particles within the mold so as to cause the pre-foamed particles to foam and expand, thereby fusion-bonding the resulting expanded particles to obtain the expansion-molded article.
An apparatus suitable for use in the production of an expansion-molded article from internally pressurized pre-foamed particles comprising a thermoplastic resin, said apparatus comprising:
- a pressurizing tank having an internal volume capable of storing therein under pressure a quantity of said pre-foamed particles sufficient to form at least one of said expansion-molded article, said pressurizing tank including a particle outlet;
- a pressure feed system for pressurizing the interior of said pressurizing tank under a pressure sufficient to apply a predetermined internal pressure to said pre-foamed particles;
- at least one pressurizing hopper including a particle inlet and a particle outlet and capable of holding a suitable portion of said particles sufficient to form said expansion-molded article;
- a gate mechanism for opening or closing the particle outlet of said at least one pressurizing hopper;
- particle transfer means for transferring said suitable portion of particles in a pressurized state from said pressurizing tank through the particle outlet thereof to said at least one pressurizing hopper through the particle inlet thereof;
- at least one molding machine having a molding compartment for receiving said suitable portion of particles through a particle filling opening, and further including heating means for heating the particles within the molding compartment to cause the heated particles to expand and fuse to form said expansion-molded article;
- and
- a particle filling system for causing the particles to flow out from the pressurizing hopper through the particle outlet thereof and for filling the particles into the molding compartment through said particle filling opening thereof, while maintaining the particles under pressure.
Dependencies are inferred from the claim text.