CA2092451A1 - Trifunctional siloxane hydride fluids - Google Patents

Trifunctional siloxane hydride fluids

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Publication number
CA2092451A1
CA2092451A1 CA 2092451 CA2092451A CA2092451A1 CA 2092451 A1 CA2092451 A1 CA 2092451A1 CA 2092451 CA2092451 CA 2092451 CA 2092451 A CA2092451 A CA 2092451A CA 2092451 A1 CA2092451 A1 CA 2092451A1
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CA
Canada
Prior art keywords
siloxane
trifunctional
weight percent
hydride
siloxane hydride
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
CA 2092451
Other languages
French (fr)
Inventor
Michael A. Lucarelli
William J. Raleigh
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
General Electric Co
Original Assignee
General Electric Co
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Filing date
Publication date
Application filed by General Electric Co filed Critical General Electric Co
Publication of CA2092451A1 publication Critical patent/CA2092451A1/en
Abandoned legal-status Critical Current

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Abstract

ABSTRACT OF THE INVENTION
There is disclosed a family of novel trifunctional branched siloxane hydride fluids and a process for their synthesis. The novel compositions are useful as crosslinking agents for vinyl organosiloxanes and as intermediates for the preparation of a variety of organo functional siloxanes.

Description

2~92~1 TRIFUN~TIONAL SILOXAN~ HYDRIDE FLUIDS
The prasent invention relates to a process for the synthesis of trifunctional branched siloxane hydride fluids. More particularly the present invention relates to trifunctional branched siloxane hydride fluids and their use as crosslinking agents in the production of organosiloxanes.
BACXGROUND OF THE INVENTIO~
The hydrosilation reaction was discovered in the 1940's and is now one of the best known and most widely practiced reactions in organosilicon chemistry, including use in a wide variety of large scale commercial applications. Various hydrosilation methods were known for effecting the addition of an organosilicon material, having a hydrogen atom attached to ~ilicon, to an aliphatically unsaturated mate:r~al having either olefinic or acetylenic unsaturation, re~ulting in the formation of an adduct having a new silicon-carbon linkage.
Prior to the present invention, in all of these hydrosilation methods, the hydrosilation methods were based on the use of linear silicone based hydride technolo~y. See, Modic, United States Patent No.
3,457,214.
It has now been found that a new family of silicon hydrides for use in hydrosilation reactions have been found which exhibit many important nPw properties.
These novel trifunctional branched siloxane hydride fluids may be used in a variety of crosslinking agents fox a variety of SiH/SiCH=CH2 platinum catalyzed reactions, as well as intermediates to produce a variety of organo functional silanes.

~ U Y h ~ ~ 1 SUMMARY OF THE PRESENT INVENTION

According to the present invention there is provided a trifunctional branched siloxane hydride fluid selected from those having the general formula:
TDXM~3 TD D~M~
TDxDay~3 wherein T represents an alkyl trisiloxy, D represents a dialkylsiloxy, D~ represents an alkylhydrodisiloxy, M
represents a trialkylsiloxy, M~ represents a dialkylhydrosiloxy, and x is an integer which is 1 or greater, and preferably varies from about 5 to about 200 and more preferably from about 10 to about 150.
According to the present invention there is also provided a process for preparing a trifunctional branched siloxane hydride selected from those having the general formulae: TDxM~3, TDXN yM~3~ or TDXD yM3 wherein T
represents an alkyl tri~3iloxy, D represents a dialkylsiloxy, Da represents an alkylhydrodisiloxy, M
represents a trialkylsiloxy, Ma represents a dialkylhydrosiloxy, and x is an integer which is 10 or greater, and preferably varies from about 10 to about 150 inclusive, comprising: (a) adding a TD siloxane to a reaction vessel, wherein T and D are as above defined, (b) heating the reaction vessel to a temperature of from about 50 to about 150C in the presence of a catalyst, (c) .cooling and neutralizing the reaction mixture; and (d) recovering the trifunctional branched siloxane hydride product.

2~2~

DETAILED DESCRIPTION OF THE PRESENT INVENTION

The present invention discloses novel siloxane hydride fluids and a process for their synthesis. These novel siloxane hydride fluids are trifunctional branched siloxane fluids of the general formulae:
TDXM~3 TD D~M~
TD D~M
wherein T represents an alkyl trisiloxy, D represents a dialkylsiloxy, D~ represents an alkylhydrodisiloxy, M
represents a trialkylsiloxy, M~ represents a dialkylhydrosiloxyl and x is 1 or greater, and preferably varies from about 5 to about 200 . In preferred embodiments, the alkyl group of the T, D, Da, M
and M~ components comprises methyl.
These novel trifunctional branched siloxane hydride fluids are formed by a process c~mprising (a) adding a TD siloxane to a reaction vessel, wherein T and D are as above defined, (b) heating the reaction vessel to a temperature of from about 50 to about 150C in the presence of a catalyst, (c) cooling and neutralizing the reaction mixture; and (d) recovering the trifunctional branched siloxane hydride product.
The TD siloxane can be prepared by methods known to those skilled in the art, such as by the co-hydrolysis of an alkyltrichlorosilane with the corresponding dialkylchlorosilane. Preferably, the TD
siloxane comprises from about 5 to about 25 weight percent T, and more preferably from about 7.25 to about 25 weight percent T, based on the total weight of the TD
siloxane.

2~3~2~
It is also contemplated as within the scope of the present invention, that a siloxane tetramer and/or a tetraalkyldisiloxane component, such as tetrame~hyl-disiloxane, can be added to the reaction vessel with the5 TD siloxane. Further, other siloxanes, such as methyl hydride cyclics and hexamethylsiloxanes can also be added to the reaction mixture.
The catalyst which is employed in the reaction is an equilibration catalyst, and can ~e any of those known to persons of skill in the art. It is also within the scope of the present claims that the catalyst includes an acid clay, such as Filtrol~ 20, from Harshaw Chemical Co., or carbon black and a mineral acid, such as sulfuric acid, and/or an organic acid. Typically, from about 0.1 to about 2.0 weight percent of equilibration catalyst based on the weight of the siloxane reactants is added to the reacti~n mixture.
The reaction is then carried out at a temperature of from about .~0 to about 150C, preferably about 100C, for a time of from about 3 to about 5 hours.
The reaction mixture is coolecl to a temperature of about 50C and neutralized by the addition of a neutralizing agent. Typically the neutralizing agent is a magnesium oxide, but may also comprise other basics. The cooled and neutralized mixture is then filtered, such as through a Celite filter, to remove impurities.
By varying the amounts and types of siloxane reactants, the product trifunctional branched siloxane can be prepared having varying amounts of Dx and D~y units in the siloxane.
The trifunctional siloxane hydride fluids of the present invention are useful as crosslinking agents for a variety of silicon hydride/vinyl silicon platinum catalyzed reactions.

2 ~

The curing reaction which takes place between the vinyl-functional polysiloxane and the SiH-containing crosslinking agent is an addition cure reaction, known as hydrosilation. The compositions of the present invention may be thermally cured by means of a platinum group metal catalyzed crosslinking reaction between the vinyl groups of the base polymer and the SiH reaction sites of the crosslinker.
Suitable hydrosilation catalysts to be employed in the present invention are known to persons skilled in the art and include transition group metal catalysts utilizing such precious metals as ruthenium, rhodium, palladium, osmium, iridium, copper and platinum, and complexes of these metals. Preferred are platinum metal catalysts. Examples of such hydrosilation catalysts are described in, inter alia, Lamoreaux, United States Patent No. 3,220,972; Karstedt, United States Patent Nos.
3,715,334; 3,775,452 and 3,814,730.
The compositions can also be utilized as intermediates to produce a variety of organo functional siloxanes following standard hydrosilation techniques.
~hese include the production of RT~ compositions ~ormed by reacting the trifunctional branched siloxane hydride fluids with a linear organosiloxane polymer having hydroxyl terminal groups in the presence of a metal salt, chelate, organometall~c compound as a crosslinking catalyst. See, e.g., Beers, United States Patent No., 4,257,932; Smith, United States Patent No., 4,490,500;
and White, United States Patent No. 4,395,526.

~ o ~

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following examples illustrate the present invention. They are not to be construed to limit the scope of the appended claims in any manner whatsoever.

To a vessel equipped with a stirrer, thermometer and condenser are added the following siloxanes: 33.4 weight percent of TD siloxane (7.25~ T);
49.1 weight percent tetramer, 8.7 weight percent methyl hydride cyclics and 8.8 weight percent of hexamethyldisiloxane. A platinum catalyst is then added along with 0.1 weight percent of sulfuric acid concentrate and 0.5 weight percent of carbon black. The mixture is then heated to 100C for 3-5 hours, and then cooled to 50C. 0.5 weight percent of magnesium oxide (MgO) is then charged to the vessel to neutralize, and the reaction mixture is filtered through Celite.
There is produced a trifunctional siloxane hydride fluid of the formula TD30DB4M3.

The procedure of Example 1 is followed using 67.1 weight percent of TD siloxane (7.25% T), 18.3 weight percent of tetramer and 14.6 weight percent of tetramethyldisiloxane as the siloxanes; 0.1 weight percent of sulfuric acid, 0.5 weight percent of carbon black in the catalyst mixture; and 0.5 weight percent of MgO as the neutralizer.
There is produced a trifunctional siloxane hydride fluid of the formula TDlsMB3.

2 ~

The procedure of Example 1 is followed using 38.3 weight percent of TD siloxane (7.25% T), 52.8 weight percent of tetramer and 8.4 weight percent of tetramethyldisiloxane as the siloxanes; 0.1 weight percent of sulfuric acid and 0.5 weight percent of carbon black in the catalyst mixture; and 0.5 weight percent of MgO as the neutralizer.
There is produced a trifunctional siloxane hydride fluid of the formula TD30k~3.

The procedure of Example 1 is followed usins 45.1 weight percent TD siloxane ~7.25% T), 14.7 weight percent methyl hydride cyclics, 30.4 weight percent tetramer and 9.8 weight percent tetramethyldisiloxane as the siloxanes; 0.1 weight percent sulfuric acid and 0.5 weight percent carbon black in the catalyst mixture; and 0.5 weight percent MgO as the neutralizer.
There is produced a trifunctional siloxane fluid of the formula TD20D~sM~3.

The procedure of Example 1 is followed using:
8.95 weight percent TD (7.25 weight percent T); 88.4 weight percent tetramer, 1.95 weight percent tetramethyldisiloxane, 0.1 weight percent sulfuric acid, 0.3 weight percent carbon black and 0.3 weight percent MgO.
There is produced a trifunctional siloxane fluid of the formula TD13sM~3.

2~2f~

The trifunctional siloxane hydride fluid of Example 1 is employed as a crosslinking agent to a vinyl terminated polydimethylsiloxane in the presence of a platinum-olefin complex catalyst, as described in Karstedt, United States Patent No. 3,775,452, and curing is effected by heating the mixture.
A cured vinyl dimethylsiloxane is produced.

The above-mentioned patents are hereby incorporated by reference.
Many variations of the present invention will suggest themselves to those skilled in the art in light of the above-detailed description. All such obvious modifications are within the full intended scope of the appended claims.

Claims (13)

1. A trifunctional branched siloxane hydride selected from those having the general formula:
TDxMH3 TDxDHyMH3 TDxDHyM3 wherein T represents an alkyl trisiloxy, D represents a dialkylsiloxy, DH represents an alkylhydrodisiloxy, M
represents a trialkylsiloxy, MH represents a dialkylhydrosiloxy, and x is 10 or greater.
2. A trifunctional branched siloxane hydride as defined in Claim 1 wherein said alkyl group of the T, D, DH, M and MH components comprises methyl.
3. A trifunctional branched siloxane hydride as defined in Claim 1 wherein x is an integer varying from about 10 to about 150.
4. A process for preparing a trifunctional branched siloxane hydride selected from those having the general formula:
TDxMH3 TDxDHyMH3 TDxDHyM3 wherein T represents an alkyl trisiloxy, D represents a dialkylsiloxy, DH represents an alkylhydrodisiloxy, M
represents a trialkylsiloxy, MH represents a dialkylhydrosiloxy, and x is 10 or greater, said process comprising:
(a) adding a TD siloxane to a reaction vessel, wherein T and D are as above defined, (b) heating the reaction vessel to a temperature of from about 50 to about 150°C in the presence of a catalyst, (c) cooling and neutralizing the reaction mixture; and (d) recovering the trifunctional branched siloxane hydride product.
5. A process as defined in Claim 3 wherein x is an integer varying from about 10 to about 150.
6. A process as defined in Claim 4 wherein a siloxane tetramer and a tetraalkyldisiloxane are also added to the reaction vessel in step (a).
7. A process as defined in Claim 4 wherein said catalyst is selected from a platinum catalyst, an acid clay and sulfonic acids.
8. A process as defined in Claim 4 wherein said TD siloxane comprises from about 5 to about 25 weight percent T.
9. A process as defined in Claim 4 wherein said TD siloxane is prepared by the co-hydrolysis of an alkyltrichloro-silane with a dialkylchlorosilane.
10. A process as defined in Claim 4 wherein said neutralizing step is carried out in the presence of a neutralizing agent.
11. A process as defined in Claim 10 wherein said neutralizing agent comprises magnesium oxide.
12. A cured vinyl polydimethylsiloxane resin prepared from a trifunctional siloxane hydride fluid as defined in Claim 1.
13. The invention as defined in any of the preceding claims including any further features of novelty disclosed.
CA 2092451 1992-04-29 1993-03-25 Trifunctional siloxane hydride fluids Abandoned CA2092451A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US87587092A 1992-04-29 1992-04-29
US875,870 1992-04-29

Publications (1)

Publication Number Publication Date
CA2092451A1 true CA2092451A1 (en) 1993-10-30

Family

ID=25366510

Family Applications (1)

Application Number Title Priority Date Filing Date
CA 2092451 Abandoned CA2092451A1 (en) 1992-04-29 1993-03-25 Trifunctional siloxane hydride fluids

Country Status (1)

Country Link
CA (1) CA2092451A1 (en)

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