US4125510A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of improving crack resistance of siloxane molding compositions
Assignee: Dow Silicones Corp
•
Filing: 1977-03-01
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Granted: 1978-11-14
•
Expires: 1997-03-01
Abstract
Abstract The crack resistance of phenyl silicone molding compounds containing siliceous fillers is improved by incorporating therein from 4 to 15 percent by weight based on the combined weight of the resins of an aromatic epoxy resin having an epoxide equivalent of from 475 to 2000. These molding compounds are particularly suitable for encapsulating electronic devices such as diodes.
Inventors
- 👤 Robert C. Antonen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 10:15
CPC Classifications
C; C04; C04B; C04B26/00; C04B26/30; C04B26/32; C08; C08L; C08L83/00; C08L83/04; C08G; C08G77/00; C08G77/04; C08G77/14; C08G77/16; C08G77/70
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
131 words
A method of improving the crack resistance of siloxane molding compositions consisting essentially of (1) a phenyl siloxane resin containing silicon-bonded hydroxyl groups and having a phenyl to silicon ratio of 0.3:1 to 0.9:1 and an R to silicon ratio of 0.4:1 to 1.1:1 and a total phenyl plus R to silicon ratio of 1:1 to 1.4:1 in which R is an aliphatic hydrocarbon radical of 1 to 2 C atoms, and (3) from 70 to 85 percent by weight of a siliceous filler based on the total weight of the composition, the improvement comprising adding to the composition from 2 to 15 percent by weight, based on the combined weights of (1) and (2) of (2) an aromatic epoxy resin having an epoxy equivalent weight of not more than 2000.
Claim 2
Independent Claim
131 words
A method of improving the crack resistance of siloxane molding compositions consisting essentially of (1) a phenyl siloxane resin containing silicon-bonded hydroxyl groups and having a phenyl to silicon ratio of 0.3:1 to 0.9:1 and an R to silicon ratio of 0.4:1 to 1.1:1 and a total phenyl plus R to silicon ratio of 1:1 to 1.4:1 in which R is an aliphatic hydrocarbon radical of 1 to 2 C atoms, and (3) from 70 to 85 percent by weight of a siliceous filler based on the total weight of the composition, the improvement comprising adding to the composition from 2 to 15 percent by weight, based on the combined weights of (1) and (2) of (2) an aromatic epoxy resin having an epoxy equivalent weight of not more than 2000.
Claim 3
Dependent Claim
17 words
The method of claim 1 in which the epoxy resin is a diglycidyl ether of bisphenol A.
Claim 4
Dependent Claim
21 words
The method in accordance with claim 2 in which the epoxy resin has an epoxy equivalent weight of 300 to 1000.
Claim 5
Dependent Claim
30 words
The method of claim 3 in which the epoxy resin is employed in amount from 4 to 12 percent by weight based on the combined weights of (1) and (2).
Claim 6
Dependent Claim
10 words
The method of claim 2 in which R is methyl.
Claim 7
Dependent Claim
10 words
The method of claim 3 in which R is methyl.
Claim 8
Dependent Claim
10 words
The method of claim 4 in which R is methyl.
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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) | 1981-11-13 | 1982-05-15 | 1982-11-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-11-13 | 1986-05-15 | 1986-11-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-11-13 | 1990-05-15 | 1990-11-14 | $7700.00 | Window Closed / Lapsed |