Plastic and nonmetallic article shaping or treating: processes – Pore forming in situ – By mechanically introducing gas into material
Patent
1988-12-01
1990-07-17
Thurlow, Jeffery
Plastic and nonmetallic article shaping or treating: processes
Pore forming in situ
By mechanically introducing gas into material
264 85, 264237, 2643281, 2643288, 26432811, 264572, 425 4R, 425146, 425546, 425559, 425563, 425564, 425570, 425812, 425817R, B29C 4500, B29C 4534, B29C 4576, B29C 6720
Patent
active
049420062
ABSTRACT:
An injection molding method and nozzle for use therein wherein first and second variable pressures are applied to a piston of a valve mechanism of the nozzle so that a differential fluid pressure on the piston causes a tip portion of the valve mechanism to alternately open and close. In this way, the tip portion communicates the flow of resin from a nozzle body of the nozzle to an injection aperture of a mold. Differential pressure on the piston prevents a fluid which distributes the molten resin over the interior surfaces of the mold from entering the flow path of the molten resin in the nozzle body. The fluid preferably is a gas, such as nitrogen. Preferably, the piston is mounted for reciprocating movement within the nozzle body and the first pressure is provided by the resin during resin injection and the second pressure is partially applied by the nitrogen gas. Preferably, the valve mechanism includes a counterbalance mechanism which is set to prevent fluid entry into the mold until the tip portion of the valve mechanism is closed. The resulting article is then cooled to a temperature below the softening point of the resin, the pressure is relieved within the article and the mold is opened to remove the article. The nozzle may also be utilized in making structural foam articles from a foamable resin. The pressure within the mold is relieved to permit foaming by the foamable resin after injection of the foamable resin.
REFERENCES:
patent: 3966372 (1976-06-01), Yasuike et al.
patent: 4101617 (1978-07-01), Friederich
patent: 4106887 (1978-08-01), Yasuike et al.
patent: 4129635 (1978-12-01), Yasuike et al.
patent: 4140672 (1979-02-01), Kataoka
patent: 4333608 (1982-06-01), Hendry
Michael Ladney
Tentoni Leo B.
Thurlow Jeffery
LandOfFree
Method of and apparatus for injection molding with pressurized-f does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method of and apparatus for injection molding with pressurized-f, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of and apparatus for injection molding with pressurized-f will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-94253