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US 5,474,723 AGranted
Method of forming a shaped article of resin using cavity enlargement to induce foaming
OwnerMaki Horikoshiinventor
Life of this patent
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Abstract
A shaped article of resin disclosed which possesses a two-ply construction wherein the outer side of a core-layer resin foamed at a void ratio in the range of from 30 to 80% is wrapped with a skin-layer resin. This shaped article of resin is produced by a method which comprises injecting a skin-layer resin into a molding mold and subsequently or simultaneously injecting therein a core-layer resin foamed in advance in a molding device.
Claims8
A method for producing a shaped resin article, which comprises:
- filling a first storage cavity having an inner volume with a molten core-layer resin which contains a foaming agent while applying pressure to a screw in the first storage cavity in such a manner as not to foam said molten core-layer resin,
- filling a second storage cavity with a molten skin-layer resin which does not contain a foaming agent,
- increasing the inner volume of the first storage cavity by retracting the screw of the first storage cavity to reduce the pressure exerted on the core-layer resin, thereby foaming said core-layer resin within the first storage cavity, and
- injecting the skin-layer resin from the second storage cavity and subsequently or simultaneously therewith injecting the foamed core-layer resin from the first storage cavity into a molding cavity to thereby form a shaped resin article.
1 more element
A method for producing a shaped resin article, which comprises:
- filling a first storage cavity having an inner volume with a molten core-layer resin which contains a foaming agent while applying pressure to a screw in the first storage cavity in such a manner as not to foam said molten core-layer resin,
- filling a second storage cavity with a molten skin-layer resin which contains a foaming agent,
- increasing the inner volume of the first storage cavity by retracting the screw of the first storage cavity to reduce the pressure exerted on the core-layer resin, thereby foaming said core-layer resin within the first storage cavity,
- injecting the skin-layer resin from the second storage cavity and subsequently or simultaneously therewith injecting the foamed core-layer resin from the first storage cavity into a gas pressurized molding cavity, and
- releasing the gas pressure from said molding cavity after injecting the skin-layer resin and the core-layer resin into the molding cavity to thereby form a shaped resin article.
2 more elements
Dependencies are inferred from the claim text.