US3935292A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Cast polymerization process with improved mold release
Assignee: Japan Atomic Energy Agency
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Filing: 1974-03-20
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Granted: 1976-01-27
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Expires: 1994-03-20
Abstract
Abstract A process for producing cast polymer is carried out by using a mold treated by the following steps: coating the glass surface of the mold with polysiloxane; heating the coated glass surface at a temperature in the range of from more than about 150° C. to a temperature at which the coated polysiloxane is not hardened yet; and wiping the coated surface of baked polysiloxane. Not only is easy mold release attained, but also repeated use of the same mold becomes possible.
Inventors
- 👤 Hiroshi Okubo
- 👤 Masamichi Kato
- 👤 Isao Kaetsu
- 👤 Akihiko Ito
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 09:03
CPC Classifications
B; B29; B29C; B29C33/00; B29C33/56; B29C33/60; B29C33/62; B29C33/64; B29L; B29L2011/00; B29L2011/0016
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
146 words
A process for producing a cast polymer article using a mold with a glass surface, comprising: coating the glass surface of the mold with polysiloxane or silicone oil; heating the polysiloxane or silicone oil coating on the surface at a temperature in the range of from about 150°C to about 350°C at which the percent gel fraction of the baked polysiloxane or silicone oil determined by extracting in toluene at 60°C for 48 hours is at the most 50 percent; wiping the coated and baked polysiloxane or silicone oil to remove excess polysiloxane or silicone oil to thus smoothen the coating; charging a material to be cast selected from the group consisting of a polymerizable monomer, a polymerizable prepolymer or a mixture thereof into the treated mold as above; polymerizing the material by a suitable polymerization means; and removing the resulting cast article from the mold.
Claim 2
Dependent Claim
146 words
A process for producing a cast polymer article using a mold with a glass surface, comprising: coating the glass surface of the mold with polysiloxane or silicone oil; heating the polysiloxane or silicone oil coating on the surface at a temperature in the range of from about 150°C to about 350°C at which the percent gel fraction of the baked polysiloxane or silicone oil determined by extracting in toluene at 60°C for 48 hours is at the most 50 percent; wiping the coated and baked polysiloxane or silicone oil to remove excess polysiloxane or silicone oil to thus smoothen the coating; charging a material to be cast selected from the group consisting of a polymerizable monomer, a polymerizable prepolymer or a mixture thereof into the treated mold as above; polymerizing the material by a suitable polymerization means; and removing the resulting cast article from the mold.
Claim 3
Dependent Claim
31 words
A process in accordance with claim 1 wherein said polysiloxane or silicone oil is selected from the group consisting of linear and circular dimethyl polysiloxane, branched methyl polysiloxane, and mixtures thereof.
Claim 4
Dependent Claim
23 words
The process of claim 1 in which heating is carried out at a temperature in the region of about 200°C - about 300°C.
Claim 5
Dependent Claim
19 words
The process of claim 1 in which heating time is in the region of 2 minutes - 40 hours.
Claim 6
Dependent Claim
19 words
The process of claim 1 in which heating time is in the region of 20 minutes - 4 hours.
Claim 7
Dependent Claim
29 words
The process of claim 1 in which heating is carried out at a temperature in the region of about 200°C - about 300°C for 20 minutes - 4 hours.
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) | 1979-01-26 | 1979-07-28 | 1980-01-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-01-26 | 1983-07-28 | 1984-01-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-01-26 | 1987-07-28 | 1988-01-27 | $7700.00 | Window Closed / Lapsed |