Patent US4581768A successfully refreshed from Google Patents.
Patent US4701491A successfully refreshed from Google Patents.
US4701491A
Expired / Lapsed
US
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Silicone extrusion stock
Assignee: Dow Silicones Corp
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Filing: 1986-10-27
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Granted: 1987-10-20
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Expires: 2006-10-27
Abstract
Abstract A method of producing an improved extruding silicone rubber stock consists essentially of mixing together a polydiorganosiloxane having a Williams Plasticity Number of from 125 to 180 and a get slope activity of less than 25 and a reinforcing silica filler having a surface area of greater than 150 m 2 /g and a hydrophobic surface from a silane treatment to give a stock which has a Garvey rating of greater than 3.5 at an extrusion rate of 20 rpm.
Inventors
- 👤 Peter Lamont
- 👤 Carl M. Monroe
- 👤 Olgerts Skostins
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 14:10
CPC Classifications
C; C08; C08K; C08K9/00; C08K9/04; C08K9/06
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
135 words
A method of producing a silicone rubber stock which gives an improved extrusion, as measured by a Garvey die, consisting essentially of mixing together ingredients (A) 100 parts by weight of polydiorganosiloxane of the formula ##STR2## where R is selected from the group consisting of methyl, ethyl, vinyl, propyl, and 3,3,3-trifluoropropyl, X is R or a hydroxyl radical, x is such that the Williams Plasticity Number is from 125 to 180, and the gel slope activity of the polydiorganosiloxane is less than 25, and (B) from 20 to 75 parts by weight of reinforcing silica filler having a surface area of greater than 150 m 2 /g and a silane surface treatment, and is hydrophobic, to give a stock which has a Garvey rating of greater than 3.5 at an extrusion rate of 20 rpm.
Claim 2
Independent Claim
135 words
A method of producing a silicone rubber stock which gives an improved extrusion, as measured by a Garvey die, consisting essentially of mixing together ingredients (A) 100 parts by weight of polydiorganosiloxane of the formula ##STR2## where R is selected from the group consisting of methyl, ethyl, vinyl, propyl, and 3,3,3-trifluoropropyl, X is R or a hydroxyl radical, x is such that the Williams Plasticity Number is from 125 to 180, and the gel slope activity of the polydiorganosiloxane is less than 25, and (B) from 20 to 75 parts by weight of reinforcing silica filler having a surface area of greater than 150 m 2 /g and a silane surface treatment, and is hydrophobic, to give a stock which has a Garvey rating of greater than 3.5 at an extrusion rate of 20 rpm.
Claim 3
Dependent Claim
20 words
The method of claim 1 in which there is also present sufficient plasticizer to give shelf life to the stock.
Claim 4
Dependent Claim
30 words
The method of claim 2 in which the plasticizer is present in an amount of from 1.0 to 2.5 parts by weight per 10 parts by weight of filler (B).
Claim 5
Dependent Claim
29 words
The method of claim 1 in which the reinforcing silica has a surface area of from greater than about 150 m 2 /g to about 200 m 2 /g.
Claim 6
Dependent Claim
33 words
The method of claim 4 in which the silane surface treatment gives a carbon content of from about 1.0 to 1.3 percent by weight, based upon the total weight of the treated filler.
References Cited (Backward Citations)
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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) | 1990-10-19 | 1991-04-20 | 1991-10-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-10-19 | 1995-04-20 | 1995-10-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-10-19 | 1999-04-20 | 1999-10-20 | $7700.00 | Window Closed / Lapsed |