Plastic and nonmetallic article shaping or treating: processes – Pore forming in situ – By gas forming or expanding
Patent
1998-04-28
1999-11-16
Kuhns, Allan R.
Plastic and nonmetallic article shaping or treating: processes
Pore forming in situ
By gas forming or expanding
264 48, 264 55, 264321, B29C 4420
Patent
active
059851902
ABSTRACT:
A crystalline polymer resin, such as poly(ethylene terephthalate), is heated to melting. One or more blowing agents is selected wherein at least one of the blowing agents has a boiling point greater than the glass transition temperature for the resin and less than the forming temperature, such as the temperature of the mold used to form the useful article. The blowing agent(s) and resin are combined to create a mixture with a blowing agent concentration sufficient to produce a theoretical sheet foam density of less than 0.4 g/cm.sup.3. The mixture is cooled to a temperature approaching the freezing point of the mixture, and then extruded into a substantially uniform closed cell polymer foam sheet of density less than 0.4 g/cm.sup.3. The extruded sheet is then cooled by direct contact with a cooling surface at a surface temperature below the glass transition temperature such that the blowing agent(s) condenses and the sheet has a density of greater than 0.4 g/cm.sup.3 and a sheet crystallinity of less than 15%. An article is then formed from the cooled sheet by applying heat such that the condensed blowing agent(s) vaporizes and the article crystallizes at a density of less than 0.4 g/cm.sup.3 with a crystallinity of greater than 20%.
REFERENCES:
patent: 3277221 (1966-10-01), Parrish
patent: 3584090 (1971-06-01), Parrish
patent: 3637458 (1972-01-01), Parrish
patent: 4043950 (1977-08-01), Wilmsen et al.
patent: 4122047 (1978-10-01), Filip et al.
patent: 4163037 (1979-07-01), Niznik
patent: 4444832 (1984-04-01), Mazzola et al.
patent: 4462947 (1984-07-01), Huggard
patent: 4466933 (1984-08-01), Huggard
patent: 4833174 (1989-05-01), Tung
patent: 4981631 (1991-01-01), Cheung et al.
patent: 5000991 (1991-03-01), Hayashi et al.
patent: 5110844 (1992-05-01), Hayashi et al.
patent: 5128202 (1992-07-01), Subramanian et al.
patent: 5128383 (1992-07-01), Amano et al.
patent: 5223545 (1993-06-01), Kumar
patent: 5229432 (1993-07-01), Muschiatti
patent: 5234640 (1993-08-01), Amano et al.
patent: 5246976 (1993-09-01), Pontiff
patent: 5254400 (1993-10-01), Bonner, Jr. et al.
patent: 5314925 (1994-05-01), Burnell et al.
patent: 5340846 (1994-08-01), Rotter et al.
patent: 5360829 (1994-11-01), Kawabe et al.
patent: 5362763 (1994-11-01), Al Ghatta et al.
patent: 5389319 (1995-02-01), Hayashi et al.
patent: 5391582 (1995-02-01), Muschiatti et al.
patent: 5399595 (1995-03-01), Sublett et al.
patent: 5405563 (1995-04-01), Hayashi et al.
patent: 5422381 (1995-06-01), Al Ghatta et al.
patent: 5458832 (1995-10-01), Kabumoto et al.
patent: 5534215 (1996-07-01), Song et al.
patent: 5545364 (1996-08-01), Song et al.
patent: 5679295 (1997-10-01), Harfmann
patent: 5681865 (1997-10-01), Harfmann
patent: 5695709 (1997-12-01), Van Erden et al.
Genpak, L.L.C.
Kuhns Allan R.
Reinke, Esq. Wayne F.
LandOfFree
Method and system for forming low-density polymer foam article 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 and system for forming low-density polymer foam article, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and system for forming low-density polymer foam article will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1320043