US4026846A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Silicone rubber sponge composition, method of making the sponge
Assignee: Dow Silicones Corp
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Filing: 1975-07-03
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Granted: 1977-05-31
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Expires: 1995-07-03
Abstract
Abstract A sponge prepared from silicone rubber using 4,4'-oxybis(benzenesulfonhydrazide) as a blowing agent has improved heat stability when calcium oxide, magnesium oxide or a mixture of these two oxides is present in the composition. The sponge prepared using these oxides has a lower compression deflection after heat aging than the compositions which do not contain the oxides.
Inventors
- 👤 Ronald E. Kittle
- 👤 Keith E. Polmanteer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 19:08
CPC Classifications
C; C08; C08J; C08J9/00; C08J9/0066; C08J9/04; C08J9/06; C08J9/10; C08K; C08K3/00; C08K3/18; C08K3/20; C08K3/22; C08K3/34; C08K3/36; C08K5/00; C08K5/04; C08K5/14; C08J2383/00; C08J2383/04
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
123 words
In a method for making a silicone rubber sponge comprising heating a silicone rubber composition consisting essentially of a polydiorganosiloxane gum having organic groups selected from the group consisting of methyl, phenyl, vinyl, and mixtures thereof and has at least 90 percent of the organic groups being methyl, a reinforcing silica filler, an organic peroxide and 4,4'-oxybis(benzenesulfonhydrazide) above the activation temperature of the organic peroxide and the activation temperature of the 4,4'-oxybis(benzenesulfonhydrazide) whereby the blowing process and the vulcanization process take place at substantially the same time to obtain a silicone rubber sponge, the improvement consisting essentially of having present in the silicone rubber composition a finely divided metal oxide selected from the group consisting of magnesium oxide, calcium oxide, and mixtures thereof.
Claim 2
Dependent Claim
123 words
In a method for making a silicone rubber sponge comprising heating a silicone rubber composition consisting essentially of a polydiorganosiloxane gum having organic groups selected from the group consisting of methyl, phenyl, vinyl, and mixtures thereof and has at least 90 percent of the organic groups being methyl, a reinforcing silica filler, an organic peroxide and 4,4'-oxybis(benzenesulfonhydrazide) above the activation temperature of the organic peroxide and the activation temperature of the 4,4'-oxybis(benzenesulfonhydrazide) whereby the blowing process and the vulcanization process take place at substantially the same time to obtain a silicone rubber sponge, the improvement consisting essentially of having present in the silicone rubber composition a finely divided metal oxide selected from the group consisting of magnesium oxide, calcium oxide, and mixtures thereof.
Claim 3
Dependent Claim
35 words
The method in accordance with claim 1 in which the metal oxide is present in an amount of from 0.5 to 15 parts by weight based on 100 parts by weight of the polydiorganosiloxane gum.
Claim 4
Dependent Claim
15 words
The method in accordance with claim 2 in which the metal oxide is magnesium oxide.
Claim 5
Dependent Claim
21 words
The method in accordance with claim 2 in which the metal oxide is a mixture of calcium oxide and magnesium oxide.
Claim 6
Dependent Claim
101 words
A spongeable silicone rubber composition consisting essentially of A. 100 parts by weight of a polydiorganosiloxane gum having organic groups selected from the group consisting of methyl, phenyl, vinyl, and mixtures thereof, at least 90 percent of the organic groups being methyl, B. 5 to 70 parts by weight of a reinforcing silica filler, C. 0.1 to 5 parts by weight of an organic peroxide, D. 0.5 to 5 parts by weight of 4,4'-oxybis(benzenesulfonhydrazide) and E. 0.5 to 15 parts by weight of a finely divided metal oxide selected from the group consisting of magnesium oxide, calcium oxide, and mixtures thereof.
Claim 7
Dependent Claim
101 words
A spongeable silicone rubber composition consisting essentially of A. 100 parts by weight of a polydiorganosiloxane gum having organic groups selected from the group consisting of methyl, phenyl, vinyl, and mixtures thereof, at least 90 percent of the organic groups being methyl, B. 5 to 70 parts by weight of a reinforcing silica filler, C. 0.1 to 5 parts by weight of an organic peroxide, D. 0.5 to 5 parts by weight of 4,4'-oxybis(benzenesulfonhydrazide) and E. 0.5 to 15 parts by weight of a finely divided metal oxide selected from the group consisting of magnesium oxide, calcium oxide, and mixtures thereof.
Claim 8
Dependent Claim
17 words
The spongeable silicone rubber composition according to claim 5 in which the metal oxide is magnesium oxide.
Claim 9
Dependent Claim
23 words
The spongeable silicone rubber composition according to claim 5 in which the metal oxide is a mixture of calcium oxide and magnesium oxide.
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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) | 1980-05-30 | 1980-11-29 | 1981-05-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-05-30 | 1984-11-29 | 1985-05-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-05-30 | 1988-11-29 | 1989-05-31 | $7700.00 | Window Closed / Lapsed |