Patent US3883625A successfully refreshed from Google Patents.
US3883625A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for making expandable plastics
Assignee: Dow Chemical Co
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Filing: 1973-03-29
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Granted: 1975-05-13
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Expires: 1993-03-29
Abstract
Abstract Layered sheet having selectively foamable layers is prepared employing a laminate of at least three layers of synthetic resinous materials, the outer layers are relatively permeable to a blowing agent and a central layer is relatively impermeable to a blowing agent. The laminated sheet is impregnated with a fluid (either liquid or gaseous blowing agent), the sheet exposed to conditions which permit loss of the blowing agent from the outer layers and subsequently heated to foam an inner or central layer.
Inventors
- 👤 Lowell S Thomas
- 👤 Kenneth J Cleereman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 13:40
CPC Classifications
B; B32; B32B; B32B27/00; B32B27/32; B29; B29C; B29C44/00; B29C44/34; B29C44/3442; B29C44/3446; B29C44/3453; B32B27/06; B32B27/08; B32B27/30; B32B27/304; C; C08; C08J; C08J9/00; C08J9/04; C08J9/12; C08J9/34; B32B2323/00; B32B2323/04; Y; Y10; Y10S; Y10S264/00; Y10S264/05
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
141 words
A method for the preparation of a synthetic thermoplastic resinous foamable body which comprises providing a laminate having at least first and second unfoamable outer layers and at least one inner layer, the outer layers and inner layer being of synthetic resinous material, the layers being adhered together, contacting the laminate with a volatile fluid foaming agent having a boiling point not higher than 95*C. at 760 millimeters absolute pressure and a molecular weight of at least 56 to thereby impregnate at least the inner layer with foaming agent at a temperature below the softening temperature of the body, removing the foaming agent from the outer layers and subsequently heating at least a portion of the inner layer to a temperature sufficient to cause foaming or expansion by the formation of a plurality of gas-containing closed cells within the inner layer.
Claim 2
Independent Claim
141 words
A method for the preparation of a synthetic thermoplastic resinous foamable body which comprises providing a laminate having at least first and second unfoamable outer layers and at least one inner layer, the outer layers and inner layer being of synthetic resinous material, the layers being adhered together, contacting the laminate with a volatile fluid foaming agent having a boiling point not higher than 95*C. at 760 millimeters absolute pressure and a molecular weight of at least 56 to thereby impregnate at least the inner layer with foaming agent at a temperature below the softening temperature of the body, removing the foaming agent from the outer layers and subsequently heating at least a portion of the inner layer to a temperature sufficient to cause foaming or expansion by the formation of a plurality of gas-containing closed cells within the inner layer.
Claim 3
Dependent Claim
30 words
THE METHOD OF CLAIM 1 INCLUDING HEAT FORMING THE LAMINATE DURING HEATING OF THE INNER LAYER WHEREIN BOTH THE INNER AND OUTER LAYERS ARE RAISED TO A HEAT FORMING TEMPERATURE.
Claim 4
Dependent Claim
15 words
The method of claim 1 wherein at least one of the layers has multidirectional orientation.
Claim 5
Dependent Claim
20 words
The method of claim 1 wherein the foaming agent in the outer layers is removed by exposure to ambient conditions.
Claim 6
Dependent Claim
14 words
The method of claim 1 wherein the foamable body has a generally container-like configuration.
Claim 7
Dependent Claim
16 words
The method of claim 1 including the step of selectively foaming portions of the inner layer.
Claim 8
Dependent Claim
12 words
The method of claim 1 wherein the outer layers are of polyolefin.
Claim 9
Dependent Claim
19 words
The method of claim 1 wherein the inner layer is a polymer containing a major portion of vinylidene chloride.
References Cited (Backward Citations)
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US3444036A
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US3449477A
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US3531554A
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US3784658A
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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) | 1978-05-12 | 1978-11-11 | 1979-05-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-05-12 | 1982-11-11 | 1983-05-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-05-12 | 1986-11-11 | 1987-05-13 | $7700.00 | Window Closed / Lapsed |