Method for molding foamable resin

Patent metadata

Field	Value
Publication number	US-9475219-B2
Application number	US-201113634435-A
Country	US
Kind code	B2
Filing date	Apr 11, 2011
Priority date	Jun 15, 2010
Publication date	Oct 25, 2016
Grant date	Oct 25, 2016

Abstract

Before generated air bubbles grow, only the edge of a portion where strength is not to be reduced is locally cooled and solidified to form a wall of fluid. After that, a pin ( 107 ) or the like is pressed into a molten resin portion inside the edge to reduce the volume of a cavity ( 3 ), thereby reducing the size of generated bubbles. Alternatively, foaming gas is absorbed into resin so as to reduce the volume of generated air bubbles. Thus, a reduction in strength is suppressed.

First claim

The invention claimed is:

1. A method for molding foamable resin, when foamable resin is injected into a cavity formed by a first mold and a second mold and the resin is foamed, the method comprising:
disposing a frame-like nest as a part of a surface of the cavity, the nest being set at a temperature lower than a set temperature of one of the first mold and the second mold and having a recessed portion communicating with the cavity;
injecting molten foamable resin into the cavity, and solidifying the resin on the nest more quickly than on an area other than a contact area with the nest so as to form an initial solidified portion acting as a barrier of a molten resin flow, the initial solidified portion being disposed upstream and downstream of the recessed portion relative to the flow of the molten resin, and foaming of unsolidified foamable resin continuing after the initial solidified portion is formed; and
compressing the molten resin in a final solidified portion in the recessed portion so as to reduce a volume of generated gas bubbles in the resin in the final solidified portion, and the resin then being solidified by cooling, by pressing a movable core into unsolidified resin in the recessed portion after solidifying the resin in the initial solidified portion, the movable core being set at a temperature lower than the set temperature of one of the first mold and the second mold.

2. The method for molding foamable resin according to claim 1 , wherein the frame-like nest includes an opening end having a notch.

Assignees

• Fujioka Toshiyuki
• Panasonic Ip Man Co Ltd

Inventors

• Fujioka Toshiyuki

Classifications

• B29C44/0446 Primary

  by increasing the density locally by compressing part of the foam while still in the mould · CPC title

• B29C44/0407

  by regulating the temperature of the mould or parts thereof, e.g. cold mould walls inhibiting foaming of an outer layer · CPC title

• B29C35/16

  Cooling {(cooling extruded material B29C48/911; cooling preforms for blow moulding B29C49/6427; cooling blown articles B29C49/66; cooling tyres during post cure inflation B29D30/0643)} · CPC title

• B29C35/0266

  Local curing (for repairing B29C73/34) · CPC title