US4248651A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Thermoforming process of corrugated plastic board
Assignee: Sumitomo Chemical Co Ltd
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Filing: 1976-10-27
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Granted: 1981-02-03
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Expires: 1996-10-27
Abstract
Abstract An improved thermoforming process for the production of formed articles of corrugated plastic board having small radius curvatures and deep drawings, which comprises heating said corrugated plastic board at the portions to be formed into small radius curvatures or deep drawings more intensively than at the other portions, and applying pressure to said portions thereby crushing the rib structure in said portions without crushing the rib structure in said other portions.
Inventors
- 👤 Susumu Kojimoto
- 👤 Tadatoshi Ogawa
- 👤 Youzou Abe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 01:17
CPC Classifications
B; B29; B29C; B29C51/00; B29C51/08; B29C51/006; B29C51/26; B29C51/42; B29C51/421; B29C51/422; B29L; B29L2024/00; B29L2024/003; Y; Y10; Y10T; Y10T156/00; Y10T156/10; Y10T156/1002; Y10T156/1005; Y10T156/1007; Y10T156/1016; Y10T156/102; Y10T156/1039; Y10T156/1041; Y10T156/1043
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
84 words
An improved thermoforming process for the production of formed articles of corrugated plastic board comprising two sheets and corrugated ribs, parallel ribs or X-pattern ribs therebetween and having small radius curvatures and deep drawings, which comprises heating said corrugated plastic board at the portions to be formed into small radius curvatures or deep drawings more intensively than at the other portions, and applying pressure to said portions thereby crushing the rib structure in said portions without crushing the rib structure in said other portions.
Claim 2
Dependent Claim
84 words
An improved thermoforming process for the production of formed articles of corrugated plastic board comprising two sheets and corrugated ribs, parallel ribs or X-pattern ribs therebetween and having small radius curvatures and deep drawings, which comprises heating said corrugated plastic board at the portions to be formed into small radius curvatures or deep drawings more intensively than at the other portions, and applying pressure to said portions thereby crushing the rib structure in said portions without crushing the rib structure in said other portions.
Claim 3
Dependent Claim
33 words
An improved thermoforming process according to claim 1, wherein said corrugated plastic board is composite corrugated plastic board comprising corrugated plastic board as a base material and a one- or multi-layer laminating sheet.
Claim 4
Dependent Claim
17 words
An improved thermoforming process according to claim 1, wherein said radius curvature is 2 to 3 mm.
Claim 5
Dependent Claim
39 words
An improved thermoforming process according to claim 2, wherein said laminating sheet is a member selected from the group consisting of synthetic resin sheet or film, foamed synthetic resin sheet or film, synthetic leather, woven fabric and non-woven fabric.
Claim 6
Dependent Claim
43 words
An improved thermoforming process according to claim 1, wherein the forming temperature of said portions to be formed into small radius curvatures or deep drawings is about 10° to about 20° C. higher than the maximum forming temperature of the corrugated plastic board.
Claim 7
Dependent Claim
20 words
An improved thermoforming process according to claim 1, wherein said corrugated plastic board is 2 to 10 mm in thickness.
Claim 8
Dependent Claim
18 words
An improved thermoforming process according to claim 1, wherein said corrugated plastic board has an x-pattern rib structure.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-02-03 | 1984-08-04 | 1985-02-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-02-03 | 1988-08-04 | 1989-02-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-02-03 | 1992-08-04 | 1993-02-03 | $7700.00 | Window Closed / Lapsed |