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EP0490401A2
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Self-curing ceramicizable polysiloxanes
Assignee: OSI Specialties Inc
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Filing: 1991-12-13
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Granted: —
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Expires: 2011-12-13
Abstract
Abstract Polysiloxanes containing both alkylhydrosiloxane units and alkylvinylsiloxane units which polysiloxanes are siloxy-endblocked that are useful as starting materials in the preparation of silicon oxycarbide ceramic compositions, a process for their preparation, a process for preparing silicon oxycarbide ceramic compositions therefrom, and novel silicon oxycarbide ceramic compositions are described.
Inventors
- 👤 Curtis Louis Schilling, Jr.
- 👤 Thomas Charles Williams
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-04 18:34
CPC Classifications
C; C08; C08G; C08G77/00; C08G77/04; C08G77/12; C08G77/06; C08G77/08; C08G77/10; C08G77/20
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
94 words
A polysiloxane having the formula: wherein: R' is an alkyl group having 1 to 4 carbon atoms; R'' is hydrogen, a vinyl group or an alkyl group having 1 to 4 atoms; x has a value of from 1 to 2; y has a value of from 0 to 1; z has a value of from 0 or 1; with the proviso that x+y is 2, x+z is 2, y and z each has an average value of at least 0.75; and a and b each has an average value from 2 to 100.
Claim 2
Dependent Claim
18 words
A polysiloxane according to Claim 1 wherein the ratio of a to b is about 0.5:1 to 1:0.5.
Claim 3
Dependent Claim
10 words
A polysiloxane according to Claim 2, wherein R' is methyl.
Claim 4
Dependent Claim
16 words
A polysiloxane according to Claim 3, wherein one R'' is a hydrogen in each endblocking unit.
Claim 5
Dependent Claim
12 words
A polysiloxane according to Claim 3, wherein R'' is a methyl group.
Claim 6
Dependent Claim
17 words
A polysiloxane according to Claim 3, wherein one R'' is a vinyl group in each endblocking unit.
Claim 7
Dependent Claim
15 words
A polysiloxane according to Claim 1 wherein a + b is about 4 to 100.
Claim 8
Dependent Claim
47 words
A polysiloxane according to Claim 1, wherein R' is methyl; one R'' is hydrogen or a vinyl group in each endblocking unit; x, y, and z are each 1; a + b is about 4 to 50; and the ratio of a to b is about 1:1.
Claim 9
Dependent Claim
293 words
A process for the preparation of a polysiloxane having the formula: wherein: R' is an alkyl group having 1 to 4 carbon atoms; R'' is hydrogen, a vinyl group or an alkyl group having 1 to 4 atoms; x has a value of from 1 to 2; y has a value of from 0 to 1; z has a value of from 0 to 1; with the proviso that x+y must equal 2, x+z must equal 2, y and z each has an average value of at least 0.75; and a and b each has a value from 2 to 100 which process comprises (1) reacting in the presence of a sulfonic acid catalyst with agitation at ambient or higher temperature and pressure at least one siloxane selected from (i) cyclic siloxanes selected from the group consisting of (OSiR'H) c , (OSiR'CH=CH₂) c , (OSiR'₂) d , (OSiR'H) e (OSiR'CH=CH₂) f , (OSiR'₂) e (OSiR'H) f , and (OSIR'₂) e (OSiR'CH=CH₂) f wherein c and d are positive integers ranging from 3 to 10 and e and f are positive integers and e + f equals e or d; with at least one siloxane selected from group (ii) or group (iii); wherein group (ii) consists of endblocking disiloxanes of the formula: R''₃SiOSiR''₃ and wherein group (iii) consists of linear siloxanes selected from the group consisting of R''₃Si(OSiR'H) g OSiR''₃, R''₃Si(OSiR'CH=CH₂) g OSiR''₃, and R''₃Si(OSiR'₂) g OSiR''₃ wherein g is a positive integer ranging from 1 to 100; and wherein in groups (i), (ii) and (iii) R' is an alkyl group having from 1 to 4 carbon atoms and R'' is hydrogen, an alkyl group having 1 to 4 carbon atoms, or vinyl group; (2) neutralizing the catalyst; and (3) vacuum stripping the polysiloxane.
Claim 10
Dependent Claim
14 words
A process according to Claim 9 wherein the sulfonic acid catalyst is trifluoromethanesulfonic acid.
Claim 11
Dependent Claim
47 words
A process according to Claim 10 wherein the catalyst is neutralized by the addition of from about 0.04 to 10 weight percent based on the total weight of (i), (ii) and (iii) of an inorganic salt selected from the group consisting of sodium carbonate and sodium bicarbonate.
Claim 12
Dependent Claim
34 words
A process according to Claim 10 wherein from about 0.5 to 5 times the equivalent weight of a solvent selected from the group consisting of acetonitrile, dimethylsulfoxide, and hexamethylphosphoramide is added to the catalyst.
Claim 13
Dependent Claim
36 words
A process according to Claim 9 wherein the catalyst is neutralized by the addition of from about 0.04 to 10 weight percent of allyltrimethylsilane or hexamethyldisiloxane based on the total weight of (i), (ii) and (iii).
Claim 14
Dependent Claim
19 words
A process according to Claim 13 wherein the catalyst is neutralized by the addition of allyltrimethylsilane and vacuum stripped.
Claim 15
Dependent Claim
131 words
A process for the conversion of a polysiloxane having the formula: wherein: R' is an alkyl group having 1 to 4 carbon atoms; R'' is hydrogen, a vinyl group or an alkyl group having 1 to 4 atoms; x has a value from 1 to 2; y has a value from 0 to 1; z has a value from 0 to 1; with the proviso that x+y must equal 2, x+z must equal 2, y and z each has an average value of at least 0.75; and a and b each has an average value from 2 to 100 to a silicon oxycarbide ceramic composition which comprises: heating the polysiloxane to a temperature ranging from about 500 to 1300°C in an inert atmosphere consisting of nitrogen or argon at ambient pressure.
Claim 16
Dependent Claim
11 words
A ceramic composition in accordance with the process of Claim 15.
References Cited (Backward Citations)
No citation records indexed.
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