US4742142A
Expired / Lapsed
US
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Method for producing silicone rubber powder
Assignee: DuPont Toray Specialty Materials KK
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Filing: 1987-04-06
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Granted: 1988-05-03
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Expires: 2007-04-06
Abstract
Abstract Powdered, cured silicone rubber in the form of microfine particles is prepared by emulsifying a curable liquid silicone rubber composition in a mixture of water and a surfactant at a temperature of from 0 to 25 degrees C., dispersing the curable composition in water heated to a temperature of at least 25 degrees C. and recovering the resultant cured particles. The liquid silicone rubber composition is preferably maintained at a temperature of from -60 to 0 degrees C. before being emulsified.
Inventors
- 👤 Koji Shimizu
- 👤 Mitsuo Hamada
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 06:13
CPC Classifications
C; C08; C08J; C08J3/00; C08J3/12; C08J3/16; C08J3/24; C08J3/26; C08J2383/00; C08J2383/04
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
82 words
A method for preparing a cured silicone rubber powder in the form of microfine particles, said method comprising (1) emulsifying a curable liquid silicone rubber composition in a mixture comprising water and a surfactant where said mixture is maintained at a temperature of from 0 to 25 degrees C., (2) curing the liquid silicone rubber into a powder by dispersing the resultant emulsion into water maintained at a temperature of at least 25 degrees C., and (3) isolating the resultant cured powder.
Claim 2
Independent Claim
82 words
A method for preparing a cured silicone rubber powder in the form of microfine particles, said method comprising (1) emulsifying a curable liquid silicone rubber composition in a mixture comprising water and a surfactant where said mixture is maintained at a temperature of from 0 to 25 degrees C., (2) curing the liquid silicone rubber into a powder by dispersing the resultant emulsion into water maintained at a temperature of at least 25 degrees C., and (3) isolating the resultant cured powder.
Claim 3
Dependent Claim
67 words
A method according to claim 1 where said curing is obtained by either (1) a platinum catalyzed addition reaction between an organopolysiloxane containing at least two lower alkenyl radicals and an organohydrogenpolysiloxane containing at least two silicon bonded hydrogen atoms per molecule, or (2) a free radical initiated polymerization of an organopolysiloxane containing at least two vinyl radicals per molecule in the presence of an organic peroxide.
Claim 4
Dependent Claim
62 words
A method according to claim 2 where said composition cures by said platinum catalyzed addition reaction, the sum of the number of silicon bonded hydrogen atoms per molecule of said organohydrogenpolysiloxane and the number of silicon bonded lower alkenyl radicals per molecule of said organopolysiloxane is at least 5, said organopolysiloxane is a dimethylvinylsiloxy terminated dimethylpolysiloxane and said organohydrogenpolysiloxane is a methylhydrogenpolysiloxane.
Claim 5
Dependent Claim
41 words
A method according to claim 1 where the curable liquid silicone rubber composition is maintained at a temperature of from -30 to 0 degrees prior to being emulsified and the temperature of said mixture is from 5 to 10 degrees C.
Claim 6
Dependent Claim
50 words
A method according to claim 1 where said surfactant is non-ionic, the volume of the water into which the emulsion is dispersed is at least twice the volume of said emulsion and the temperature of the water into which the emulsion is dispersed is from 40 to 80 degrees C.
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) | 1991-05-03 | 1991-11-02 | 1992-05-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-05-03 | 1995-11-02 | 1996-05-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-05-03 | 1999-11-02 | 2000-05-03 | $7700.00 | Window Closed / Lapsed |