US3627729A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Catalyzed silicone resin molding composition
Assignee: Midland Silicones Ltd
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Filing: 1970-07-27
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Granted: 1971-12-14
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Expires: 1990-07-27
Abstract
Abstract A mixture of organosiloxane resin and certain catalysts has been found to be particularly useful in transfer-molding and compression-molding operations. The mixture is a siloxane resin having an organic substituent/silicon ratio of from 1/1 to 1.7/1 and at least 0.25 percent by Si bonded -OH groups, and a catalytic amount of a mixture of (a) carboxylic acid anhydride and (b) lead carbonate, lead monoxide or a mixture thereof.
Inventors
- 👤 Brian Robert Trego
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 23:39
CPC Classifications
C; C08; C08K; C08K3/00; C08K3/18; C08K3/24; C08K3/26; C08K3/20; C08K3/22; C08K5/00; C08K5/04; C08K5/09
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
21 words
A composition as claimed in claim 1 wherein the organic radicals in the organopolysiloxane resin comprise both methyl and phenyl radicals.
Claim 2
Dependent Claim
31 words
A composition as claimed in claim 2 wherein the organopolysiloxane resin has from 0.4 to 0.9 phenyl radicals per silicon atom and from 0.4 to 1.2 methyl radicals per silicon atom.
Claim 3
Dependent Claim
24 words
A composition as claimed in claim 1 wherein the organopolysiloxane resin has a silicon-bonded hydroxyl content of from 0.5 to 5 percent by weight.
Claim 4
Dependent Claim
18 words
A composition as claimed in claim 1 wherein the carboxylic acid anhydride is acetic anhydride or benzoic anhydride.
Claim 5
Dependent Claim
26 words
A composition as claimed in claim 1 wherein the catalyst contains from 0.5 to 2.0 moles of the anhydride for every mole of the lead compound.
Claim 6
Dependent Claim
13 words
A composition as claimed in claim 1 which also contains an inorganic filler.
Claim 7
Dependent Claim
105 words
A silicone molding composition consisting essentially of a mixture of (1) an organosiloxane polymer containing monovalent hydrocarbon radicals as substituents bonded to silicon, the ratio of such hydrocarbon radicals to silicon being in the range from 1.0/1 to 1.7/1, and containing from 0.25 to 5.0 percent by weight silicon-bonded hydroxyl radicals and (2) 0.5 to 5 percent by weight, based on the weight of siloxane polymer (1), of a catalyst mixture of (a) a carboxylic acid anhydride and (b) lead carbonate, lead monoxide or a mixture thereof, in a ratio of from 0.5 to 2.0 mols of anhydride (a) per mol of lead compound (b).
Claim 8
Dependent Claim
12 words
The composition of claim 8 wherein the organosiloxane polymer is a methylphenylsiloxane.
Claim 9
Dependent Claim
32 words
The composition of claim 9 wherein the organosiloxane polymer contains an average of from 0.4 to 0.9 phenyl radicals per silicon atom and from 0.4 to 1.2 methyl radicals per silicon atom.
Claim 10
Dependent Claim
16 words
The composition of claim 8 wherein the carboxylic acid anhydride is acetic anhydride or benzoic anhydride.
Claim 11
Dependent Claim
11 words
The composition of claim 8 which also contains an inorganic filler.
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) | 1974-12-13 | 1975-06-14 | 1975-12-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-12-13 | 1979-06-14 | 1979-12-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-12-13 | 1983-06-14 | 1983-12-14 | $7700.00 | Window Closed / Lapsed |