Patent US4519964A successfully refreshed from Google Patents.
US4519964A
Expired / Lapsed
US
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Process for preparing plastic articles having an outer shell and inner foam core
Assignee: Rotoplas Ltd
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Filing: 1984-01-19
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Granted: 1985-05-28
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Expires: 2004-01-19
Abstract
Abstract A process for preparing plastic articles having an outer rigid shell and an inner polystyrene foamed core, whereby pre-expanded polystyrene beads are foamed and fused inside a hollow thermoplastic shell, comprising, coating the inside of the shell prior to introducing the polystrene beads into the hollow shell, with a thermoplastic bonding layer.
Inventors
- 👤 Haim Rosen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 21:54
CPC Classifications
B; B29; B29C; B29C44/00; B29C44/02; B29C44/12; B29C44/18; B29C41/00; B29C41/02; B29C41/04; B29C44/34; B29C44/36; B29C44/38; B29C44/44; B29C44/445; B29C37/00; B29C37/0025; B29C37/0028; B29C44/3415; B29C44/3426; B29K; B29K2023/00; B29K2023/04; B29K2023/08; B29K2023/083; B29K2025/00
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
80 words
A process for preparing plastic articles having a rigid outer shell filled with a core of foamed polystyrene, comprising: (a) forming a shell of rigid polyethylene; (b) molding into the inner surface of the shell a layer of a thermoplastic polymer selected from copolymers of ethylene and a member selected from the group consisting of alkylacrylates, alkylmethacrylates and vinyl esters; (c) filling the shell with pre-expanded polystyrene beads and expanding the beads to fully occupy the hollow of the shell.
Claim 2
Dependent Claim
80 words
A process for preparing plastic articles having a rigid outer shell filled with a core of foamed polystyrene, comprising: (a) forming a shell of rigid polyethylene; (b) molding into the inner surface of the shell a layer of a thermoplastic polymer selected from copolymers of ethylene and a member selected from the group consisting of alkylacrylates, alkylmethacrylates and vinyl esters; (c) filling the shell with pre-expanded polystyrene beads and expanding the beads to fully occupy the hollow of the shell.
Claim 3
Dependent Claim
16 words
A process according to claim 1 wherein the rigid shell of polyethylene is a multilayered composite.
Claim 4
Dependent Claim
19 words
A process according to claim 2 wherein the composite is a dense layer and a foam layer of polyethylene.
Claim 5
Dependent Claim
21 words
A process according to any one of claims 1, 2 or 3 wherein the thermoplastic layer is an ethylene-vinyl acetate copolymer.
Claim 6
Dependent Claim
31 words
A process according to any one of the claims 1, 2 or 3 wherein the rigid shell of polyethylene and the inner thermoplastic layer are prepared in situ by rotational molding.
Claim 7
Dependent Claim
24 words
A process according to claim 4 wherein the rigid shell of polyethylene and the inner thermoplastic layer are prepared in situ by rotational molding.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-05-27 | 1988-11-26 | 1989-05-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-05-27 | 1992-11-26 | 1993-05-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-05-27 | 1996-11-26 | 1997-05-28 | $7700.00 | Window Closed / Lapsed |