EP0602875A2
Expired / Lapsed
EP
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Room temperature vulcanizing fluorosilicone compositions
Assignee: General Electric Co
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Filing: 1993-12-07
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Granted: —
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Expires: 2013-12-07
Abstract
Abstract A method for continuously producing a room temperature vulcanizable composition is disclosed. A base mixture of a silanol stopped fluorosilicone polymer, a silica filler and iron oxide are processed in an extruder at an elevated temperature between about 50 and 200°C. Thereafter, a tin based catalyst, an acetoxy cross-linking agent and an optional adhesion promoter are added to the extruder near the exit port. The resulting material has improved storage stability.
Inventors
- 👤 John Joseph Dziark
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-06 02:37
CPC Classifications
C; C08; C08K; C08K3/00; C08K3/18; C08K3/20; C08K3/22; C08L; C08L83/00; C08L83/04; C08L83/08; Y; Y10; Y10S; Y10S528/00; Y10S528/901
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
280 words
A method for continuously producing a shelf stable room-temperature vulcanizable composition from an extruder having a first supply port, an exit port, and a second supply port located along said extruder between said first supply port and said exit port, said method comprising the steps of: (1) supplying a base composition (A) to said extruder at said first supply port and maintaining the temperature of the base composition between 50 and 200°C, said base composition (A) comprising: (A1) 100 parts by weight of a silanol terminated fluorosilicone having the formula HO(RR¹SiO) x OH, wherein each R is a monovalent hydrocarbon radical free of aliphatic unsaturation containing from 1 to about 8 carbon atoms, each R¹ is a fluorinated monovalent hydrocarbon free of aliphatic unsaturation having from 1 to about 8 carbon atoms and x varies so that (A1) has a viscosity of about 600 to about 300,000 cps at 25°C; (A2) from about 3 to about 25 parts by weight based upon (A1) of a silica filler having a surface area of about 100 to 300 m²/gm in an untreated state, (A3) up to about 200 parts by weight based upon (A1) of finely divided Fe₂O₃ having an average particle size ranging from about 0.05 to about 5 microns; (2) adding a catalyst solution (B) to said extruder at said second supply port, said catalyst solution (B) comprising: (B1) up to about 0.5 parts by weight based upon 100 parts of the base composition (A) of a tin based catalyst; and (B2) from about 2 to about 15 parts by weight based upon 100 parts of the sum of (A1), (A2) and (A3) of at least one acetoxy cross-linking agent.
Claim 2
Dependent Claim
33 words
The method as defined in claim 1, wherein (B) further comprises: (B3) up to about 4 parts by weight based upon 100 parts of the sum of (A1), (A2) and (A3) of diacetoxydibutoxysilane.
Claim 3
Dependent Claim
13 words
The method as defined in claim 1, wherein (A2) is trimethyl silyl treated.
Claim 4
Dependent Claim
19 words
The method as defined in claim 1, wherein (B1) comprises at least one of (a) dibutyltindilaurate and (b) dibutyltindiacetate.
Claim 5
Dependent Claim
20 words
The method as defined in claim 1, wherein (B2) comprises at least one of (a) methyltriacetoxy silane and (b) ethyltriacetoxysilane.
Claim 6
Dependent Claim
24 words
The method as defined in claim 1, wherein said base polymer (A) is processed at a temperature ranging from about 75 to about 150°C.
Claim 7
Dependent Claim
26 words
The method as defined in claim 1, wherein said base polymer (A) is processed for up to about 5 minutes before adding the catalyst solution (B).
Claim 8
Dependent Claim
127 words
A shelf stable room temperature vulcanizable composition having been continuously produced in an extruder having an exit port, a first supply port upstream of said exit port, and a second supply port at a location along said extruder between said first supply port and said exit port, said composition comprising: a fluorosilicone polymer, a silica filler and a ferrous oxide which are supplied to said extruder at said first supply port and which are processed at a temperature ranging from about 50 to about 200°C to form a base composition; and a catalyst solution including a tin based catalyst and an acetoxy cross linking agent added to the base composition in the extruder at said second supply port between the first supply port and the exit port.
Claim 9
Dependent Claim
195 words
A room temperature vulcanizable composition as in claim 8, wherein said fluorosilicone polymer comprises: (A1) 100 parts by weight of a silanol terminated fluoro polymer having the formula OH(RR¹SiO) x OH, wherein each R is a monovalent hydrocarbon radical free of aliphatic unsaturation containing from about 1 to about 8 carbon atoms, each R¹ is a fluorinated monovalent hydrocarbon free of aliphatic unsaturation containing from 1 to about 8 carbon atoms and x varies so that (A1) has a viscosity of about 600 to about 300,000 cps at 25°C; said silica filler comprises: (A2) from about 3 to about 25 parts by weight based upon (A1) of a treated silica filler having a surface area of about 100 to 300 m²/gm in an untreated state; said cross-linking agent comprises: (B3) from about 2 to about 15 parts by weight based upon 100 parts of the sum of (A1) and (A2) of at least one acetoxy cross-linking agent selected from the group consisting of methyltriacetoxy silane and ethyltriacetoxysilane; and said tin based catalyst is present in an amount up to about 0.5 parts by weight based upon 100 parts of the sum of (A1) and (A2).
Claim 10
Dependent Claim
28 words
A room temperature vulcanizable composition as in claim 8, further comprising (A3) finely divided Fe₂O₃ having an average particle size ranging from about 0.05 to about 5 microns.
Claim 11
Dependent Claim
25 words
A room temperature vulcanizable composition as in claim 8, further comprising up to about 4 parts by weight based upon (A1) of an adhesive promoter.
References Cited (Backward Citations)
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