US3737266A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Mold for preparing a shaped article made of foamed thermoplastic resin
Assignee: Sekisui Kasei Co Ltd
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Filing: 1971-01-11
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Granted: 1973-06-05
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Expires: 1991-01-11
Abstract
Abstract A novel non-metallic double-walled mold for the molding of foamable thermoplastic resin by dielectric heating is provided. The mold is constructed by a special method to provide a thin uniform inner wall spaced apart from the outer wall, but supported by the outer wall to prevent deformation by the force exerted by the foamable resin during expansion. Using the mold, smooth-surfaced foamed articles which conform to the contours of the mold are produced.
Inventors
- 👤 K Yamamoto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 03:46
CPC Classifications
B; B29; B29C; B29C33/00; B29C33/02; B29C33/08; B29C44/00; B29C44/34; B29C44/3415; Y; Y10; Y10S; Y10S425/00; Y10S425/812
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
196 words
A closable mold for the dielectric heating of foamable thermoplastic particles comprising a. a thin inner wall of rigid non-metallic low power loss material surrounding a mold cavity, said inner wall 1. having a plurality of minute apertures spaced at intervals over its entire surface, the size of said apertures being such as to permit the passage of fluid, but to prevent the passage of foamed thermoplastic resin particles, and 2. being of a thickness sufficient to withstand deformation by the force exerted by the expansion of the foamable resin particles; b. a thick, tough outer wall of rigid non-metallic low power loss material surrounding completely said inner wall and being spaced apart therefrom, the space separating the inner and outer wall being equal to or less than the thickness of the inner wall; c. a plurality of supports positioned at predetermined intervals in the space separating each of the inner and outer walls, said supports serving to connect the inner and outer walls and to reinforce the thin inner wall to prevent deformation thereof; and d. at least one vent passing through said outer wall and connecting the space between the walls with the atmosphere.
Claim 2
Dependent Claim
196 words
A closable mold for the dielectric heating of foamable thermoplastic particles comprising a. a thin inner wall of rigid non-metallic low power loss material surrounding a mold cavity, said inner wall 1. having a plurality of minute apertures spaced at intervals over its entire surface, the size of said apertures being such as to permit the passage of fluid, but to prevent the passage of foamed thermoplastic resin particles, and 2. being of a thickness sufficient to withstand deformation by the force exerted by the expansion of the foamable resin particles; b. a thick, tough outer wall of rigid non-metallic low power loss material surrounding completely said inner wall and being spaced apart therefrom, the space separating the inner and outer wall being equal to or less than the thickness of the inner wall; c. a plurality of supports positioned at predetermined intervals in the space separating each of the inner and outer walls, said supports serving to connect the inner and outer walls and to reinforce the thin inner wall to prevent deformation thereof; and d. at least one vent passing through said outer wall and connecting the space between the walls with the atmosphere.
Claim 3
Dependent Claim
125 words
being of a thickness sufficient to withstand deformation by the force exerted by the expansion of the foamable resin particles; b. a thick, tough outer wall of rigid non-metallic low power loss material surrounding completely said inner wall and being spaced apart therefrom, the space separating the inner and outer wall being equal to or less than the thickness of the inner wall; c. a plurality of supports positioned at predetermined intervals in the space separating each of the inner and outer walls, said supports serving to connect the inner and outer walls and to reinforce the thin inner wall to prevent deformation thereof; and d. at least one vent passing through said outer wall and connecting the space between the walls with the atmosphere.
Claim 4
Dependent Claim
125 words
being of a thickness sufficient to withstand deformation by the force exerted by the expansion of the foamable resin particles; b. a thick, tough outer wall of rigid non-metallic low power loss material surrounding completely said inner wall and being spaced apart therefrom, the space separating the inner and outer wall being equal to or less than the thickness of the inner wall; c. a plurality of supports positioned at predetermined intervals in the space separating each of the inner and outer walls, said supports serving to connect the inner and outer walls and to reinforce the thin inner wall to prevent deformation thereof; and d. at least one vent passing through said outer wall and connecting the space between the walls with the atmosphere.
Claim 5
Dependent Claim
61 words
A closable mold of claim 1 which is constructed of at least two separate interconnectable parts, each part comprising a spaced apart inner and outer wall, the separation of said parts forming at least two disconnected spaces separating said inner and outer walls of said mold, and at least one vent connecting each disconnected space between said walls with the atmosphere.
Claim 6
Dependent Claim
31 words
A closable mold of claim 2 wherein the diameter of said vents are restricted so that the fluid accumulating in said spaces during molding develops pressure before escaping through said vents.
Claim 7
Dependent Claim
68 words
A closable mold of claim 1 wherein said supports are formed by providing a roughened surface on one of the opposing sides of said inner and outer walls and said inner and outer walls are positioned in incipient contact, the space separating said inner and outer walls being of sufficient width to permit the passage of fluid and the irregular protrusions on said roughened surface forming said supports.
Claim 8
Dependent Claim
38 words
A closable mold of claim 1 wherein the surfaces of the opposing sides of said inner and outer walls are smooth and integral supports extending from said outer wall connect said inner and outer walls at predetermined intervals.
Claim 9
Dependent Claim
26 words
A closable mold of claim 5 wherein the diameter of said supports is approximately four to six times the width of the space separating said walls.
Claim 10
Dependent Claim
27 words
A closable mold of claim 1 wherein the rigid non-metallic low power loss factor material used for both said inner and outer walls is fiberglass-reinforced polyester resin.
Claim 11
Dependent Claim
30 words
A closable mold of claim 1 where said minute apertures have a diameter of about 0.5 to 5.0 mm and are spaced at intervals of one aperture per square cm.
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) | 1976-06-04 | 1976-12-04 | 1977-06-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-06-04 | 1980-12-04 | 1981-06-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-06-04 | 1984-12-04 | 1985-06-05 | $7700.00 | Window Closed / Lapsed |