US4435523A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for manufacturing articles of foamed thermoplastic material and article produced thereby
Assignee: COULSON HEEL Inc 301 POPLAR ST HANOVER PA 17331
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Filing: 1982-08-24
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Granted: 1984-03-06
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Expires: 2002-08-24
Abstract
Abstract A process for producing injection molded articles of foamed thermoplastic material via injecting of a molten mass of thermoplastic material containing a foaming agent into a mold cavity is improved so as to substantially reduce production time by the utilization of a step introducing a cold compressed gas into the mold cavity internally of the injected mass of material, while it is still at least internally molten. The article produced by the process is characterized by an outer skin of tightly structured material surrounding a body of microcellular foam material having an internal void or voids bounded by material of a tightly structured nature.
Inventors
- 👤 Giuseppe Ponzielli
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 13:27
CPC Classifications
B; B29; B29C; B29C44/00; B29C44/02; B29C44/10; B29C44/105; B29C45/00; B29C45/17; B29C45/1703; B29C45/1704; Y; Y10; Y10S; Y10S264/00; Y10S264/83
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
104 words
A process for producing injection molded articles of foamed thermoplastic material comprising the steps of: (A) injecting a molten mass of thermoplastic material containing a foaming agent into at least one mold cavity of an injection mold; (B) after the elapse of a relatively brief period of time from step (A), introducing a refrigerated compressed gas into the mold cavity internally of the injected mass of material, while it is still at least internally molten; (C) cooling said mass of material into an article utilizing said internally introduced gas; (D) terminating step (B) and shortly thereafter opening the mold for removal of said article.
Claim 2
Dependent Claim
104 words
A process for producing injection molded articles of foamed thermoplastic material comprising the steps of: (A) injecting a molten mass of thermoplastic material containing a foaming agent into at least one mold cavity of an injection mold; (B) after the elapse of a relatively brief period of time from step (A), introducing a refrigerated compressed gas into the mold cavity internally of the injected mass of material, while it is still at least internally molten; (C) cooling said mass of material into an article utilizing said internally introduced gas; (D) terminating step (B) and shortly thereafter opening the mold for removal of said article.
Claim 3
Dependent Claim
13 words
A process according to claim 1, wherein said compressed gas is compressed air.
Claim 4
Dependent Claim
40 words
A process according to claim 1 or 2, wherein step (C) is performed utilizing coolant circulated through walls of the mold as well as to the gas introduced during step (B), a skin of tightly structured material being formed thereagainst.
Claim 5
Dependent Claim
23 words
A process according to claim 3, wherein said thermoplastic material is selected from the group consisting of polyethylene, polypropylene, polystyrene, and thermoplastic rubber.
Claim 6
Dependent Claim
44 words
A process according to claim 3, wherein said mold is provided with at least one core projecting into the mold, wherein a strengthening column of tightly structured material is formed about said core within a void area created within the mass by step (B).
Claim 7
Dependent Claim
23 words
A process according to claim 5, wherein said thermoplastic material is selected from the group consisting of polyethylene, polypropylene, polystyrene, and thermoplastic rubber.
Claim 8
Dependent Claim
19 words
A process according to claim 1 or 2, wherein step (B) is commenced approximately 36 seconds after step (A).
Claim 9
Dependent Claim
57 words
A process according to claim 1 or 2, wherein, after removal of the article and any runner flash associated therewith from the mold, the mold is closed and thereafter said compressed gas is reintroduced into the mold cavity so as to expel from an injector receiving bushing of the mold, any of the thermoplastic material remaining therein.
Claim 10
Dependent Claim
25 words
A process according to claim 1 or 2, wherein said thermplastic material is selected from the group consisting of polyethylene, polypropylene, polystyrene, and thermoplastic rubber.
Claim 11
Dependent Claim
12 words
A process according to claim 9, wherein said foaming agent is azobisformamide.
Claim 12
Dependent Claim
13 words
A foamed thermoplastic article produced by the process of claim 1 or 2.
References Cited (Backward Citations)
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Cited
US4033710A
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US4115491A
Cited
US4140672A
Cited
US4106887A
Cited
US4247515A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-03-06 | 1987-09-05 | 1988-03-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-03-06 | 1991-09-05 | 1992-03-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-03-06 | 1995-09-05 | 1996-03-06 | $7700.00 | Window Closed / Lapsed |