GB2315756A

GB2315756A - Process for preparing hydrogen siloxane copolymers

Info

Publication number: GB2315756A
Application number: GB9714960A
Authority: GB
Inventors: Susan Adams Nye; Donna Ann Riccio; Brenda S Wutzer
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1996-07-30
Filing date: 1997-07-16
Publication date: 1998-02-11
Anticipated expiration: 2017-07-16
Also published as: JPH10114826A; GB9714960D0; GB2315756B; FR2751975B1; FR2751975A1; DE19731682A1

Abstract

A process for preparing siloxane copolymers comprises polymerising a hydrogen rich siloxane with a cyclic siloxane in the presence of a catalytic lewis acid. The lewis acid is preferably a phosphonitritic compound. Linear hydrogen-containing siloxane copolymers are also claimed.

Description

2315756 60SI-1852 1 PROCESS FOR PREPARING HYDROGEN SILOXANE COPOLYMERS

Field of the Invention

The present invention relates to a catalyst and process for the preparation of hydrogen siloxane copolymers. The process of the present invention makes possible the synthesis of new compositions of matter, mixed silicone polymers possessing mixed functionalities.

BackgE2und of the Invention Polydimethylsiloxane fluids may be conveniently -prepared by any of several synthetic methods. A common and widely used industrial process to prepare such fluids involves the hydrolysis of halo-functional silanes followed by condensation. A second process begins with cyclic organosiloxanes utilizing a ring-opening polymerization to produce either a kinetically or equilibrium controlled mixture of linear and cyclic organosiloxane compounds.

Ring-opening polymerization of cyclic organosiloxanes may be accomplished by either acid or base catalysis. The catalysts that have been successfully employed range from very acidic catalysts such - as trifluoromethane sulfonic acid to very basic such as potassium hydroxide or potassium silanolate. A wide variety of acid catalysts have been employed to catalyze ring opening polymerization, sulfuric acid, acid washed clays, acidic ion exchange resins and linear phosphonitrilic chlorides (LPNq.

60SI-1852 2 While ring opening polymerization may be accomplished with either an acidic or basic catalyst, the preparative chemistry of hydrogen containing siloxanes (i.e. silyl hydrides) is restricted to the acidic catalysts. When a basic catalyst is used, the ring opening polymerization proceeds, but base catalyzed hydride abstraction produces hydroxy functionalities in place of the hydrogen functionalities, and the material condenses through the silanol groups. While this produces a polymer, it produces a cross-linked polymer in contrast to a linear polymer.

Process considerations in the choice of an acidic catalyst for the 10 preparation -of hydrogen organosiloxanes tend to require the milder acid catalysts in contrast to sulfuric acid and trifluoromeffiane sulfonic acid because these acids are very strong and highly corrosive. The use of such strong acids requires the use of special alloys in process vessels to avoid acid induced corrosion and contamination of the resulting produd- Milder acid catalysts such as the acid washed clays and acidic ion exchange resins possess drawbacks that while avoiding the corrosion and contamination problems associated with strong acid attack on metal process -vessels, cause other problems. The acidic ion exchange resins do not maintain catalytic activity well for any significant and economically useful period of time, requiring frequent regeneration or refreshment Acid washed clays are generally used as powders to improve contacting efficiency between the reaction substrate and the catalyst which necessitates a downstream filtration to remove the acid washed clay catalyst fines from the product Further, acid washed clays generally contain residual amounts of water that contributes to a hydride silanol interchange that results in a gradual and undesired condensation polymerization of the hych-ide product By comparison to the stronger acid catalysts, these milder acid catalysts suffer from lower reaction rates and thus a lower production of product per unit time at any given temperature.

60SI-1852 3 While the kinetic rate deficiencies of any given catalyst may be offset by an increase in temperature, this solution has at least two serious drawbacks. The first is that as temperature is changed, i.e. increased, the.relative proportions of reactants, desired products and undesired by- products change. This change may either benefit the desired process or be a detriment depending on the relative amounts of the desired product as a function of the increased temperature because the equilibrium constant for the reaction is a function of temperature. As the temperature is increased, the amount of energy furnished the reaction to increase the temperature must be increased (for endoth6rmic reactions) and this almost always adversely affects the process economics. There is thus a complex balancing between the desired reaction rate, the desired product mix, catalyst activity and process operating variables.

In contrast- to the acid catalysts that must either be neutralized, e.g.

sulfuric acid, or separated from the product, e.g:. acid washed clays, phosphonitrilic halides, particularly linear phosphonitrilic chlorides (LPNC), 'have found particular use for the redistribution and condensation of organosiloxane oligomers. These LPNC catalysts may be used at fairly low levels in the reaction being catalyzed, e.g. between 25 and ZOOO ppm. An additional advantage is that the catalyst may be left in the product and thermally deactivated if desired. This procedure usually does not result in any significant contamination of the product While the LPNC catalysts have been particularly useful for redistribution and condensation reactions involving silicones and siloxanes, they have not usually been used for ring opening polymerization because of the low rates associated with these catalysts in reactions of this type. While it is possible to achieve acceptable reaction rates in the synthesis of hydride siloxane organosiloxane copolymers when the hydride level is above approximately 1,000 ppm, the rate of ring opening polymerization in the 60SI-1852 4 presence of a low hydride level siloxane 300 ppm) is extremely slow requiring a matter of days as opposed to hours. Thus LPNC materials would not be expected to be particularly well suited to catalyze ring opening polymerization in the presence of low hydride content siloxanes to make low hydride content sfloxane polymers.

Summla of the Invention The process of the present invention comprises a process for the production of sfloxane copolymers comprising:

(a) selecting a hydrogen rich sfloxane having an active hydrogen content above about 0.100 mole percent active hydrogen; and (b) polymerization of a cyclic siloxane and said hydrogen rich siloxane in the presence of a catalytic Lewis acid compound producing thereby a copolymeric siloxape. The process of the present invention is conducted in a temperature ranging fro m about 50 to about 100 OC and in the presence of a hydrogen rich sfloxane compound or mixtures thereof having on average an active hydrogen content above about 0.100 mole percent hydrogen.

The preferred Lewis acid compounds that catalyze the process of the present invention are selected from the group consisting of 1) (X3P(NPX2)j%)+PX6- where n is an integer of from 1 to 6 and X is a halide; 2) NP(NPX2).NP)(3)+PV where n is an integer of from 1 to 6 and X is a halide; 3) (X3P(NPX2)nNPX3)+EXm- where E is an element having an electronegativity value of from 1.2 to 2 with m an integer of from 3 to 8 and X is a halide; 4) O(X)2-ayaP(NPX2)bNPX3-cyc where b is an integer ranging from 0 to 8, a is 0 or 1, c is 0 or 1, Y is OH, OR' or R'CO2 where TV is alkyl or aryl and X is a halide; 60SI-1852 5 5) O(X)2-ayaP(NPX2)bNP(O)X2-cyc where b is an integer ranging from 0 to 8, a is 0 or 1, c is 0 or 1, Y is OH, OR' or R'CO2 where Wis alkyl or aryl and X is a halide; 6) X3-p(H0)pP(NPX2)mNP(O)X2, where m is an integer ranging from 0 to 6 and p is 0 or land X is a halide; and 7) X3P(NM2)mNPX2(0) where m values can vary from 0 to 6 and X is a halide.

Further, the process of the present invention provides for a new class of sfioxane polymers having the formula:

M.Dq T,0w having at least two D. where each Dq is different from every other Dqand each Dq has the formula:

Dq = SMIR202.12 where each RI..nd R2 in each Dq is independently selected from the group is consisting. of hydrogen and one to forty carbon at6m monovalent hydrocarbon radicals where each subscript q of Dq is independently one or greater with M = R4R5MQ12 where R4, R5 and R6 are each independently selected from the group consisting of hydrogen and one to forty carbon atom monovalent hydrocarbon radicals where the stoichiometric subscript u of M is non- zero and positive; T =R7SiQ/2where R7 is selected from the group consisting of hydrogen and one to forty carbon atom monovalent hydrocarbon radicals with the stoichlometric subscript r of T zero or positive; and Q Si0412 with the stoichiometric subscript s of Q is zero or positive; subject to the limitation that one of R', R2.. R4, Rs, R6.. and R7 is hydrogen and that one of R', R2, R4, Rs, R6, and R7 which is not hydrogen is an alkenyl group having from two to forty carbon atoms. A preferred composition of the new compounds is where the subscripts r and s are zero. Thus a particularly 60SI-1852 6 preferred composition prepared by the process of the present invention has the formula: M.Dq, having at least two Dq where each Dq is different from every other Dq and each Dq has the formula: Dq SiRT20212 where each R' and R2 in each Dq is independently selected from the group consisting of hydrogen and one to forty carbon atom monovalent hydrocarbon radicals where each subscript q of D. is independently one or 10 greater with- M = R4R5R6S0312 where R4, R5 and R6 are each independently selected from the group consisting of hydrogen and one to forty carbon atom monovalent hydrocarbon radicals where the stoichiometric subscript u of M is non-zero and positive; subject to the limitation that one of R, R2, R4, RS, and is R6is hydrogen and that one of R, R2, R4, R-5, and R6 Which is not hydrogen is an alkenyl group having from two to forty carbon atoms.

Detafled Description of the Invention

We have disclosed that silanolate catalysts may be used for an initial ring opening polymerization reaction of cyclic organosiloxanes followed by the introduction of phosphonitrilic halide catalyst and hydrogen containing organosiloxane for the subsequent redistribution and condensation reaction to produce a hydrogen containing organosiloxane copolymer conducted in the same reaction vessel in U. S. serial number 08/ 688,578 filed July 30, 1996.

Thus the process disclosed comprises the following steps:

1) D. --> HOSiRIW(DJSiRIR20H base catalyst where D = SiRIR20212with R' and R' independently selected from one to forty carbon atom monovalent hydrocarbon radicals and q > x, with x generally ranging as follows 3 < x < 8. The base catalyst may be any 60SI-1852 7 generally known in the art to polymerize cyclic organosiloxanes, however, the catalyst must be capable of neutralization by an acidic species, either Arrhenius acid, Bronsted acid or Lewis acid. The preferred acidic neutralization agent is a Lewis acid selected from the group of phoshonitrilic halides. Catalysts such as an alkali metal silanolate, an alkali metal hydroxide, and tetra-organo-substituted ammonium hydroxide such as tetramethyl. ammonium hydroxide and the like are preferred.

2) Base catalyst (from reaction 1)) + Lewis acid catalyst -+ neutralization complex, 3) MDHpM + HOSiRIR2(Dq)SiRIR20H -+ MDHpDqM Lewis acid catalyst where DH = SiR3HO2/2 where R3 is selected from one to forty carbon atom monovalent hydrocarbon radicals (alternatively DH = SiRIR202/2 with R1 and R2 selected from the group of hydrogen and one to fo-ty carbon atom monovalent hydrocarbon radicals where one of RI and R2is hydrogen) and where M = M5116SOI/2where R4, R5 and R6 are each independently selected from the group consisting of hydrogen and one to forty carbon atom monovalent hydrocarbon radicals where the subscripts p and q are positive integers independently ranging from about 1 to about 1,000, preferably from about 1 to about 700, more preferably from about 1 to about 500, and most preferably from about from about 1 to about 400. It is to be noted that the process is most advantageous when it is desired to make copolymers having fairly low levels of hydride present i.e. when the stoichiometric subscript q in the copolymer is very much larger than the stoichiometric subscript p.

The Lewis acid catalyst for reaction 3) is selected from the group of phosphonitrific halide catalysts as disclosed and taught in U. S. patent 5,420,221; as well as those and including but not limited to:

(X3P(NPX2),.PX3)PX6- where n is an integer of from 1 to 6 and X is a halide selected from the group consisting of F, Cl, Br, and L- 60SI-1852 8 (X3P(NPX2),NPX3)+PX6- where n is an integer of from 1 to 6 and X is a halide selected from the group consisting of F, Cl, Br, and.

(X3P(NPX2),NPX3)+EX.- where E is an element having an electronegativity value of from 1.2 to 2 such as AI, Sb, P, Sn, Zn and Fe with 5 m an integer of from 3 to 8.1 O(X)2-aYaP(NPX2)bNPX3-cYc where b is an integer ranging from 0 to 8, a is 0 or 1, c is 0 or 1 Y is selected from the group consisting of Oa OR' and ICCO2 where Wis alkyl or aryl; O(X)2-ayaP(NPX2)bNP(O)X2-cyc where b is an integer ranging from 0 to 8, a is 0 or 1, c is 0 or 1, X is a halogen selected from the group consisting of fluorine, chlorine, bromine, and iodine, Y is selected from the group consisting of OH, OR' and WC02 where R' is alkyl or aryl; X3-p(H0),yP(NPX2)mNP(O)X2, is where X is a halogen selected from the group consisting of F, Cl, Br, and and m is an integer ranging from 0 to 6 and p is 0 or 1; and X3P(NPX2)mNM2(0) where m values can vary from 0 to 6.

The foregoing two-step process is useful when the active hydrogen content of the hydrogen organosiloxane component or precursor is low. I now disclose that when the active hydrogen content of the precursor is high, the base catalyzed reaction may be dispensed with because the Lewis Acid catalyst will conduct both reactions resulting in the process and copolymers of the present invention. Thus when the mole fraction Si-H or mole percent active hydrogen in MDHpM, MHDHpM, MHDHpW, or other active hydrogen containing precursor is above about 0.100 mole percent hydrogen, preferably above about 0.500 mole percent hydrogen, more preferably above about 0.750 mole percent hydrogen, and most preferably above about 1.100 mole percent hydrogen, the following type reaction occurs:

60SI-1852 9 4) MU.DKpM + D. -+ MD.DHpDqM Lewis acid catalyst where IY is a different D group and D is a previously defined, the subscript (x either assumes the values of p or is zero and x, p and q are as previously defined. It should be noted that the addition of other copolymerizable species, i.e. species containing T and Q groups will not interfere with the production of copolymers containing all four silicone structural units, MD, T, and Q if desired, thus reaction 4) is a specific example of the reaction, specifically for linear copolymers. The degree of polymerization or copolymerization may be controlled by the amount of any M-rich compound added to the reaction mixture. It is to be noted that mixtures of active hydrogen compounds may be used as the active hydrogen source.

The one-step process is not only dependent on the mole percent or mole fraction of active hydrogen (hydride-) components present in the reaction mixture it is also dependent on temperature as well. The copolymerization reaction has an optimum temperature between 50 and 100 OC- At 50 < the reaction is slow while at 100 OC the reaction terminates prematurely before reaching equilibrium, as measured by weight percent solids. It should be noted that weight percent solids is defined as an indicator of reaching equilibrium as usually between 85 and 89 weight percent, allowing for variations in experimental measurements. Comparisons of the reaction. kinetics between the copolymerization of octamethylcyclotetrasiloxane (D4) and tetramethyltetravinylcyclotetrasiloxane (D4111) show a marked deceleration of reaction rate for the vinyl species. Thus the one-step copolymerization may be run between 50 and 100 oC, preferably between about 60 and about 90 oC, more preferably between about 60 and about 80 OC, and most preferably between about 70 and about 80 -C. These ranges are primarily for guidance in selecting reaction conditions because it is not always desirable to simply maximize reaction rate by increasing 60SI-1852 10 temperature within this range. The reaction may be accomplished outside this range, at temperatures below about 50 OC the reaction will, be slow to approach equilibrium and at temperatures above 100 OC the reaction may terminate before reaching equilibrium.

It is preferred that the initial ring opening polymerization also be conducted in the presence of an M rich chain terminating source. Thus while it is preferred to u short chain low molecular weight M rich compounds to control the equilibrium distribution of polymer, the use of M rich compounds of greater structural complexity such as those incorporating T or Q branching points thus produces branched polymers. The reaction of the product polymer, either as the linear or branched polymer, with the hydride of reaction 3) produces a copolymer that is likewise linear or branched. The molar ratio of M.rich siloxane compound to cyclic siloxane compound governs the eq,-librium distribution of the resulting polymeric siloxane.

is While it is desirable to utilize highly M 'rich chain terminating compounds in reaction 1), the nature of the substituents on the M unit may be varied to impart additional functionality to the product of reaction 3). For example, one of the R groups on the M group may contain olefinic unsaturation or alternatively a hydride functionality. Thus a copolymer that is simultaneously an. hydride and an alkertyl organosiloxane may be prepared by reacting an M-rich compound containing an alkenyl substitution in the initial ring-opening polymerization to produce an alkenyl stopped intermediate that is then condensed and redistributed to produce the difunctional compound Mv11Y.D.MY' where M,6 = M where one or more of R4, R5 and R6 is a monovalent alkenyl radical. The process may be varied using a hydride stopped compound conbg MH units and another precursor containing Dvi units. The use of the UNC catalysts at sufficiently high levels of hydride imparts a high 60SI-1852 11 degree of synthetic flexibility in the preparation of mixed copolymers that were hitherto not easily prepared if they could be prepared at all.

Alternatively, the M-rich compound used as a chain-stopping agent in the initial ring-opening polymerization may be fairly conventional (that is unfunctionalized), such as a trimethyl stopped compound, but the cyclic compound is functionalized, e.g. a tetramer where one of the R groups on each D unit is a monovalent alkenyl radical, e.g. DY1 (an idiosyncratic symbol for an alkenyl containing D group, where the superscript vi indicates that one or more of R' and R2 is a monovalent alkenyl radical). Similarly the superscript Ph indicates that one or more of R' and R2 is a phenyl or other aromatic radical. Because of the unique selectivity of this reaction, the cyclic compounds which are the starting materials may also be functionalized. Thus if one of the R groups on the D units comprising the cyclic organosiloxanes is an"alkenyl group, an alkenyl on chain, hydride on chain is copolymer may be prepared, e.g. WiDHP1)vi,Mvi.

Instead of utilizing a single cyclic species for the ring-opening polymerization, mixtures of cyclic species may be employed and each cyclic species may be differently functionalized to prepare complex copolymers that are then reacted to form complex hydride copolymers. Such materials have the general formula:

MDHpD1q1D2q2... Dnq.TiQM,, where DHp:xt- D1q, D2q2 #... 1>q. Le. none of the various Us are alike, and the subscripts qi through qn, for all n different D groups, satisfy the definition for the subscript q as previously defined and the subscripts r, s, and U in the units Tr, Q., M. which are tri-functional, tetrafunctional or monofunctional units range over the same values as p or q.

Thus the difunctional compound M11'WpD,qW' 60SI-1852 12 where My' = M where one or more of R4, R5 and R6 is an alkenyl group is a member of this series; the difunctional compound NWHpDvi,1M where Dvi = D where R' or R2 is an alkenyl group is a member of this series; the trifunctional compound:

MY'DHpI)vigMy' is a member of this series. By a ring opening polymerization of two cyclic species, e.g. D,,, and D, a copolymer results from the first stage reaction. By a ring opening polymerization of more than two cyclic species, e.g. Mg, D2q2,... IXIn and D, a higher order polymer results from the first stage reaction.

The precursors containing the different D groups, D1q,:# D2q2#... 1>" may be differently functionalized leading to a multi-functionalized product Further, choice of a function or non-function M rich compound leads to a produd that is non-functionalized or functionalized at the terminal positions of the molecule as the case may be, Additional ractants may be is differently functionalized so that di, tri-, tetra- functionalized copolymers or terpolymers and the like may result from the reaction.

Thus the process of the present invention enables the production of the following new compositions of matter.

WIDHpDqMY', the T, Q and TQ variants M,,IDHpDqTM,,i, MviDHpDqQWi, and 20 MY'DHpDjrQW; MDHpDYIqM, the T, Q and TQ variants MDHpDY1jM, MDHPDviqQM, and IYMHpl),, iqTiQ.M; MY'DHpDviqMv the T, Q and TQ variants MviDHPDvijrMvi.. MviDHPDviqQMvi, and MviDHpD,,iqTQM-i; Mv'DHpDqDq2Mv the T, Q and TQ variants M-DHpU,,Dq2TW, MY'DHpUqiDq2QMvi, and WWplyq1Dq2TQMyi, MDHpIDY'qjDq2M, the T, Q and TQ variants MDHpDviqiDJM, MDHpl>'q1Dq2QM, and MDHpD%,Dq2TQM; 60SI-1952 13 M,"DHpDvIqiDq2Mvi, the T, Q and TQ variants Mv'DI4pl>iiD,2TMvi, Mv'DHpl)viqiDq2Q.Mvi, and MviDHPDvtqiDq2TQXviJMHDHpDqMvi, the T, Q and TQ variants MNDHpDqT,,Mvi, MHDHpDqQ.Mvi, and MHDHpDqT,Q,Mvi; MHDHpDv'qM, the T, Q and TQ variants MHDHpl)viqT,,M, NJEDHpI)v'qQ.M, and h4HI)HPI)v'qTrQsM; MHDHpDv'qMviI, the T, Q and TQ variants MHDHpDv'qT,,Mvi, MHDHpDviQMvi, and MHDHpDv'qTQ,Mv MHDHpUq,Dq2Mvi, the T, Q and TQ variants MHDHpUiD,2T,,Mvi, 10 NIHDHpgqllYq2(DsMv',, and MHDHpgqDq2TQ,Mvi; NIHDk,Dv'q,Dq2M, the T, Q and TQ variants WDHpl)r",iDq2T,,M, WDHpDviqjDq2QiM, and N4K)HpDvi,iDq2T,,QM; MHIE)HpDviq,Dq2Mvi., the T, Q and TQ variants MHDHpD,iD,2TMvi, MHDHpl)vlqiDq2QsMv', ad MHDHpDviq,Dq2TrQsMvi the higher order polymers based on D1qI # D2q2:#... -Dnq, and the T, Q and TQ variants thereof, and the like. The foregoing list is not exhaustive of all the structural permutations possible using M, MH, Mvi, MPh, D, Da-1, Drvi, DPh, DIqj, D2q2,..., I)-q,, T, TH, P', TPb, and Q it is only exemplary of the wide variety of mixed functional silicone compositions that may be prepared using these various structural components that now may be varied at will because of the synthetic flexibility afforded by the use of the Lewis acid catalysts. AD United States patents referenced herein are herewith and hereby incorporated by reference.

Definitions It is explicitly noted that where exemplary reactions recite generic reactants that mixtures of species of reactants satisfying the genus definition may be substituted therefore.

Applicant defines M rich silicone compounds to be those silicones where the ratio of M groups to the sum of D, T, and Q groups present in the 60SI-1852 14 molecule is 0.04 or greater. That is by way of explanation given a silicone of the general formula MiDjTk(2h the subscripts k and h are integers that are zero or positive and fis a positive non-zero integer, an M rich silicone is defined as one where the subscripts satisfy the criterion (i/O + k +h))1 0.04, preferably this ratio is 0.10 or greater, more preferably this ratio is 0.15 or greater, and most preferably this ratio is 0.20 or greater. M, D, T and Q have the usual definitions of structural silicone chemistry, that is M is a monofunctional chain terminating organosiloxyl group i.e. M = R4R5R6Si0112 where R4, R5 and R6 are each independently selected from the group consisting of hydrogen and one to forty carbon atom monovalent hydrocarbon radicals, D is a difunctional chain building or repeating organosiloxyl group, i.e. D = SiRT20212 with R' and R2 independently selected from hydrogen and one to forty carbon atom monovalent hydrocarbon radicals. (when R' or R2is hydrogen D = DHand when one of the is R groups is alkenyl, Dvi), T is a trifunctional chain branching organofunctional unit, i.e. T = R7Si(D3/2where R7 selected from the group consisting of hydrogen and one to forty carbon atom monovalent hydrocarbon radicals and Q is a tetrafunctional unit Si0412.

Applicant has recited a broad genus of substituent groups that may be 20 utilized in preparing compounds of the present invention. The phrase one to forty carbon atom monovalent hydrocarbon radicals includes linear alkyl, branched alkyl, linear alkenyl, branched alkenyl, linear yl, branched alkynyl, halogen substituted linear alkyl, halogen substituted branched alkyl, halogen substituted linear alkenyl, halogen substituted branched alkenyl, halogen substituted linear alkynyl, halogen substituted branched alkynyl, aryl, alkylaryl, alkenylaryl, alkynylaryl, halogen substituted aryl, halogen substituted alkylaryl, halogen substituted alkenylaryl, and halogen substituted ylaryl. By halogen substituted, Applicant defines a substituent satisfying the requirement that at least one hydrogen position of 60SI-1852 is the hydrocarbon radical is replaced with or substituted by a halogen selected from the group consisting of fluorine, chlorine, bromine, or iodine. A preferred subset of one to forty carbon atom monovalent hydrocarbon radicals includes the group of monovalent radicals consisting of hydrogen, linear or branched alkyl radicals having from 1 to about 10 carbon atoms, linear or branched alkenyl radicals having from 2 to about 10 carbon atoms, linear or branched alkynyl radicals having from 2 to about 10 carbon atoms, cycloalkyl radicals having from 3 to about 12 carbon atoms, cycloalkenyl radicals having from about 3 to 12 carbon atoms, cycloalkynyl radicals having from about 8 to about 16 carbon atoms, fluorinated linear or branched alkyl radicals having from 1 to about 10 carbon atoms, chlorinated linear or branched alkyl radicals having from 1 to about 10 carbon atoms, brominated linear or branched AUkyl radicals having from 1 to about 10 carbon atoms, fluorinated lin.-- r or branched alkenyl radicals having fom 2 to about 10 carbon atoms, chlorinated linear or branched alkenyl radicals having from 2 to about 10 carbon atoms, brominated linear or branched alkenyl radicals having from 2 to about 10 carbon atoms, fluorinated linear or branched yl radicals having from 2 to about 10 carbon atoms, chlorinated linear or branched yl radicals having from 2 to about 10 carbon atoms, brominated linear or branched alkynyl radicals having from 2 to about 10 carbon atoms, hydrocarbonoxy radicals containing at least two carbon atoms, fluorinated hydrocarbonoxy radicals containing at least two carbon atoms, chlorinated hydrocarbonoxy radicals containing at least two carbon atoms, brominated hydrocarbonoxy radicals containing at least two carbon atoms aryl radicals, linear or branched alkyl aryl radicals, fluorinated aryl radicals, chlorinated aryl radicals, brominated aryl radicals; fluorinated linear or branched alkyl-, yl-,or alkynyl aryl radicals; chlorinated linear or branched alkyl-, alkenyl-, or alkynyl aryl radicals; brominated linear or branched alkyl-, alkenyl-, or alkynyl aryl radicals. More preferred 60SI-1852 16 monovalent hydrocarbon radicals are selected from the group consisting of methyl, ethyl, propyl, trifluoropropyl, butyl, vinyl, allyl, styryl, phenyl, and benzyl. Most preferred monovalent hydrocarbon radicals are selected from the group consisting of methyl, vinyl, trifluoropropyl, and phenyl.

A copolymer is usually defined as the polymerized product of two monomers; copolymers is used in this specification in a broader sense. This broader definition of copolymers includes not only copolymers themselves, but also includes higher order mixed polymers such as terpolymers (three monomers) and higher order mixed polymers (four or more). The process of the present -invention renders the synthesis of such higher order mixed polymers particularly convenient as a mixture of cyclic siloxanes may be employed in the first stage ring opening polymerization leading to a mixed polymerof order n where n is the number of cyclic species or monomers.utilized in the ring opening polymerization. As used herein, a polymer of is order 2 is a copolymer, a polymer of order 3 is a terpolymer, etc. Thus Applicant defines polymeric order on the basis of chemically distinguishable D groups present in the resulting polymer, the number of different D groups being the polymeric order. The word copolymer as used in the appended claims means a polymer of order 2 or greater, i.e. having at least two chemically distinguishable (different) D groups.

The term Dmp refers to a set of Dq having two or more members where the n is a counting index counting the different number of D.. Thus a first set consists of D1q, and D2q2, while the second set consists of D1q1, D2,2, and D30. The counting index n thus defines both the minimum number of different D groups and the minimum polymer order of the resulting compound. When superscripts indicative of functionalization are used, i.e. an idiosyncratic superscript, in the specification, they have been used to define a functionality present in an M, D or T group. For example, H, vi, Ph i.e. DH.. Dvi, and DPI1, and the like, denote particular species of D groups where the D group bears a

60SI-1852 17 hydride functionality, H (DH), a vinyl functionality, H2C=CH(1>'), or a phenyl substituent, Cj-h- (DPh). If idiosyncratic superscripts are not used, n defines absolutely the number of different D groups and the polymer order. The tLnu Dq stands for a generalized D unit that may be varied at will, while each Dq. is a particular uniquely selected D unit In the case of M and T groups, an idiosyncratic superscript denotes a particular choice of substituent for one of the R groups R4, R5 and R6in M and for R7 in T. Applicant notes that the phrase active hydrogen means hydride functionality which is hydrogen bonded directly to a silicone atom.

Experimental The following non-limiting examples are intended to illustrate the invention.

ExlMle 1 A 500 mL round bottom flask was charged with 229.55 & 3.10 moles, of octamethylcyclotetrasiloxane (%), 1.92 & 0.0124. moles, decamethyl tetrasiloxane (MD2M, M rich compound, M/(WD) = 0.50, molar basis), and is 0.27 g of 4.3 weight percent KOH in a low molecular weight polydimethylsiloxane oil (a silanolate catalyst) having an effective base concentration of 50 ppm. The reaction was heated for 3 hours at 150 OC.

Having achieved equilibrium, 87 - 88 weight percent solids, the reaction mixture was cooled to 80 - 90 oC and 1.62 g of 2 weight percent solution in a 20 centistokes (cSt) polydimethylsiloxane oil linear of a phosphonitrilic chloride having the formula (C:bP(NPC12)21)X33),4'PCj- was added (effective concentration 138 ppm). The phosphonitrilic chloride neutralized the potassium silanolate catalyst leaving approximately 100 ppm of the linear phosphonitrilic chloride to act as a catalyst The mixture was stirred for one hour at 80 - 90,C at which time 2.23 g of 1.62 weight percent hydride linear silicone hydride polymer (MDH4osoM) was added. The reaction was stirred for an additional 2 hours at 80 - 90 OC. The resulting product was clear and 60SI-1852 18 colorless and had a hydride content of 155 ppm with a viscosity of 2275 cSt at 25 cCSilicon-29 NMR indicated that Si-H groups were randomly placed throughout the polymer chain. The hydride polymer so produced was subsequently successfully utilized for hydrosilation without further 5 purification or filtration.

EXAMle 2 The procedure of example 1 was repeated using 623 pounds of octamethylcyclotetrasiloxane, 5.2 pounds decamet:Hll tetrasiloxane, 0.3% pounds of 4.9 weight percent potassium hydroxide in silicone oil to yield 30 ppm effective catalyst, 3.92 pounds of a 2 weight percent phosphonitrilic chloride catalyst in 20 cSt silicone oil, and 6.22 pounds of 1.622 weight percent hydride silicone hydride polymer. The resulting product had viscosity of 2210 cSt at 25 -C and a hydride content of 160 ppm.. Silicon- 29 NMIR indicated that Si-H groups were randomly placed throughout thepolymer chain. The hydride polymer so produced was subsequently successfully utilized for hydrosilation without further purification or filtration.

ENAWle 3 The rapid achievement of equilibrium in the ring opening polymerization requires the presence of the base catalyst. The following attempts (Table 1) to ring open polymerize utilizing only the phosphonitrific halide catalyst indicate that synthesis of the hydride copolymer is significantly faster using two catalysts sequentially.

60SI-1852 19 Table 1: PreRaration of Uldride Silicone C2RobMers Using QMAy a Single CaWú9 Reactants Conditions WL % Solids Viscosily, % Aj22Mach cst to Eguffibrium ViscasilT, 80 oC, 6 hrs., 95 1910 40 MI)m, 60 ppin silicone UNC2 hydride polymer' D4, MIM, 80 OC, 24 hrs., 86 2192 98 silicone 100 PPIn hydride UNC2 polymer' D4, IM2M, 80 OC, 24 hrs., 82 1600 94 - silicone so ppm hydride UNC2 polymer' Notes to Table 1:

1. 1.62 weight percent hydride linear silicone hydride polymer. 2. the UNC used had the formula (C1,3P(NPC12)2Pch)+PCThe results in Table 1 indicate that in contrast to achieving equilibrium in a total of approximately 5 to 10 hours (ring opening polymerization 3 - 6 hours, redistribution and condensation 2 - 6 hours), the unaided UNC catalyst requires more than 24 hours. Thus reaction efficiency is increased by catalyzing the two reactions separately and using a first stage catalyst that can be neutralized by the second stage catalyst 60SI-1852 20 ExMRIe 4 tLeparation of MviDH,D,Mvi (g = 3, 9 = 219):

Mv'DH3DngMvi, MvI = (CH3)2CH2=CHSi0/z, DH = (CH3)HSiO2/z, D (CH3)2W/z, A 500 mL round-bottom flask was charged with 223.63 g octamethylcyclotetrasiloxane, 2.24 g 1, 3-divinyl-1, 1, 3, 3-tetramethyl disiloxane in the presence of a silanolate catalyst, 0.27 g of 4.3 wt % KOH in a siloxane oil (50 ppm). The reaction was stirred for 3 hours at 150 --C. The resulting product was 87.3 % solids, which is indicative of an equilibrium product. The reaction was cooled to between 80 - 90 (C. After coolin& the LPNC catalyst was added, 1.62 g of a 2 wt. % solution in a 20 cSt viscosity silicone oil (143 ppm). The reaction was stirred at the lower temperature for 1 hour before the addition of 2.46 g of a linear silicone hydride polymer having 1.62 weight percent hydride. The reaction was stirred at 80 - 90 oC for an additional 2 '-ours. The product was a slightly hazy fluid that was filtered through 4 2-1 weight mixture of CehteT" and Fulle?s Earth. The filtered product was dear and colorless having a viscosity of 544 cSt at 25 OC and a hydride content of 170 ppm. Silicon-29 NMR indicated both the presence of terminal alkenyl groups and that the hydride had been randomly incorporated into the silicone chain.

ExBMple 5 Preiparation of MD.I]Y'.2DH2M (]p = 10, gl = 350, 92 = 10):

MDwoDvi,oDH,oM-. The procedure of example 4 was repeated using 175.77 g of octamethy1cyclotetrasiloxane, 1.92 g of decamethyltetrasiloxane, 4.97 g of tetramethyltetravinylcydotetrasiloxane, 0.21 g of 0.27 g of 4.3 wt % KOH in a siloxane oil (49 ppm), 1.62 of LPNC catalyst solution (177 pp,m) and 3.46 g of a linear silicone hydride polymer having 1.62 weight percent hydride. The clear and colorless product had a viscosity of 883 cSt at 25 -C and, a hydride content of 288 ppm. Silicon-29 NMR indicated that both the alkenyl group and the hydride groups had been randomly incorporated into the silicone 60SI-1852 21 chain (chemical shifts: DH = -37.5 ppm, Dvi = -35.8 ppm). This reaction is an example of using a mixture of cyclic species in the ring opening polymerization to synthesize a silicone terpolymer, three precursors (monomers) containing three different D groups, minimum polymeric order 3.

le 6 Dnaration of MD9, DPh.2W93DH1,M(I2 = 10, 91 = 350, 92 = 10, 93 = 10): ME13wDPItio DviioDHioM: DPh is an idiosyncratic designation for a D group having both R groups substituted by phenyl groups. The procedure employed in examples 4 and 5 was repeated using 490.0 g of octamethylcydotetrasiloxane, 164.5 g of octaphenylcyclotetrasiloxane, 1292 g of decamethyltetrasiloxane, 35 g of tetramethyltetravinylcyclo"asfioxane, 0.82 g of 4.3 wt. % KOH in a siloxane oil (50 ppm), 4.92 of UNC catalyst solution (140 ppm) and 24.4 g of a linear silicone hydride polymer having 1.62 weight percent hydride. The clear and colorless product had a viscosity of 613 cSt at 25 C and a hydride content of 555 ppm. Silicon-29 NMR is indicated that the phenyl, hydride and alkenyl groups were randomly incorporated into the silicone chain (chemical shifts: DPItio = -48.0 ppm, Dalo DH = -37.5 ppm, DY, = -35.8 ppm). This reaction is an example of using a mixture of cyclic species in the ring opening polymerization to synthesize a silicone terpolymer, at least four precursors containing four different D groups, minimum polymeric order = 4.

le Egmparation of MD.1 IC)wi.3PH2M (p = 10, 91 = 350,,93 = 10):

A 500 mL three neck round bottom flask was charged 46.86 g of a polydimethylsfioxane (0.62 moles D (as dimethylsiloxyl), 0.009 mole M (as trimethylsiloxyl)), 7.71 g of hexamethyldisiloxane (0.0095 moles M (as trimethylsiloxyl)), 106.28 g of a hydrogen methylsiloxane (1.77 moles DH (as hydrogen methylsiloxyl)), 15.36 g of tetramethyltetravinylcyclotetrasiloxane 60SI-1852 22 (0.18 moles Dvi) and 0.79m g of 2 weight percent linear phosphonitrilic chloride (LPNC) catalyst (90 ppm LPNC). The reaction mixture was heated for two hours at 90 oC. A change in viscosity of the reaction mixture was accompanied by a change in the weight percent solids, indicative of reaction.

ExAMle 8:

Reaction Kinetics and AggMach to Eguffibrium for LPNC cLtal Med One Step CORolymerization of Tetrame!hylitetravinylcydotetrasiloxane in the Presence of a Hydride Source.

Various levels of the mole percent, mole fraction or molar level of hydride in the hydride were evaluated for the effect on reaction kinetic by mixing a hydride of the formula MDDHM(M is trimethylsiloxyl, MH is dimethy1hydrogensiloxyl, D is dimethylsiloxyl and DH is methylhydrogensiloxyl) with tetramethyltetravinylcyclotetrasiloxane in the presence of an LPNC Lewis acid catalyst Kinetic meas--irements were performed by placing the reaction mixtures in an oven at a controlled temperature and sampling the reaction mixture at various times to measure weight percent solids as an indicator of the approach to equilibrium. Results for measurements at 100,-C are presented in Table 2.

60SI-1852 23 Table 2.. Reaction Kinetics at 100 OC for Tetramelhyltetravinylúyclotetrasiloxane with a Hydride SOuxe in the Presence of an UNC Lewis Acid Catalyst llydride Hydride Somurce Temperature Time Solids Level Level (PPM) (degrees C) (hours) (weight percent) 75M MHDoDHsoMH 100 2 88 MO MHDoDHsoMH 100 4 88 SWO MHD30HWMH 100 2 79 5000 MHD3oDHsoMH 100 4 79 5000 WD30HWMH 100 8 80 1000 MDuDHsM 100 2 36 1000 MDDHsM 100 4 37 1000 MD1sDHsM 100. 11 38 500 MDlsl)%M 100 2 21 500 MDisDHsM 100 4 22 500 MDuDHsM 100 11 22 250 MDisl)%M 100 2 13 250 MDisD%M 100 4 14 250 MDuDHsM 100 11 14 Weight percent solids, did not increase with the addition of more UNC catalyst above 100 ppm.

The results in Table 2 illustrate the conclusion stated in the Detailed Description that the one-step UNC catalyzed process tends to undergo a premature termination before reaching equilibrium when the reaction is conducted at 100 oC.

60SI-1852 24 Examgk .

The process conditions of Example 8 were repeated for reactions involving D4, octamethylcyclotetrasiloxane, MDHsOM, M is trimethylsiloxyl and DH is hydrogen methylsiloxyl, with 100 ppm of LPNC, Lewis acid catalyst varying the amount of active hydrogen compound present in the 5 reaction mixture, the temperature of the reaction and the time. The results are presented in Table 3.

60SI-1852 25 Table 3: Reaction Kinetics for Octamelbylcydotetrasiloxane with a Hydride Soune in the Presence of an UNC Lewis Acid Calgúst llydride lhdride TeMRerature Time Solids Level Level Soume (PPM) (degrees Q (hours) (weight percent) 11,000 MWwM so 16 85 11,000 MDHmM 50 40 87 11,000 MD%M 100 2 91 11,000 MDHwM 100 1 73 11,000 MDHmM 100 2 77 11,000 MDH-.bl 100 4 77 5,000 MD%M so 16 79 5,000 H 50 40 87 5,000 MD%M 70 2 76 5,000 MWwM 70 4 84 5,000 MDHsoll 70 6 85.5 5,000 MWwM 70 8 87 5,000 lVMHMM 100 2 90 1,000 MD%M so 16 47 1,000 MDHmM so 40 60 1,000 MD%M so 168 60 1,000 MDHmM 100 2 84 1,000 MD%M 100 4.5 85 1,000 MDHmM 100 6.5 86 1,000 MDHmM 100 13 86 60SI-1952 26 The results presented in Table 3 demonstrate that the copolymerization reaction is fairly fast in the presence of Lewis acid catalysts such as LPNC when the cyclic species being polymerized contains a small alkyl group such as methyl.

Examrle I(P.

The process conditions of Example 9 were repeated for reactions involving Dw:, tetramethyltetravinylcyclotetrasiloxane, NMHNM, M is trimethylsiloxyl and DH is hydrogen methylsiloxyl, with 100 ppm of LPNC, Lewis acid catalyst varying the amount of active hydrogen compound present in the reaction mixture, the temperature of the reaction and the time. The results are presented in Table 4.

Table 4: Reaction Kinetics for Tetrame!hyltetravinyladotetmiloxane with a Hvdfide Source in the Presence of an LPNC Lewis Add gtalys Hydride H3Ednd Tem]perature Time Solids Level :Le Level Source (ppm) (degrees C) (hours) (weight percent) 11,000 MDHwM 70 2 81 11,000 MDHwM 70 4.5 83 11,000 MDH50M 70 22 85 11,000 MDHmM 100 2 77 11,000 MDHMM 100 4 7831 11,000 MDH.;OM 100 8 793 7,500 MDH4M 70 2 27 7,500 MDH4M 70 4 17 7,500 MDH4M 70 10 21 7,500 MDH4M 70 26 21 7,500 MD114M 70 122 25 60SI-1852 27 7,500 DH. and MMI 70 2 27 7,500 DH. and MM 70 4 32 7,500 DH. and MM 70 10 43 7,500 DH. and MM 70 26 7,500 DH. and MM 70 122 48 7,500 MDH 4M 100 2 22 7,5W MDH4M 100 5 26 5,000 MDH 4M 100 2 22 5,000 MDH4M 100 5 35 5,000 MWwM 100 2 62 5,000 MDHsoM 100 4 63 5,000 MWwM 100 8 632 5,000 MWWM 70 2 55 5,000 MWwM 70 - 4. -166 5,000 MDH-wM 70 8 77 5,000 MDHwM 70 10 82 5,000 MWwM 70 14 83 5,000 MWwM 70 20 84 1,000 MDnioM 70 2 13 1,000 MWwM 70 4 19 1,000 MWwM 70 10 26 1,000 MWwM 70 26 41 1,000 MWwM 70 122 74 1,000 MDH4M 100 2 32 1,000 MDH4M 100 4 31 1,000 MDH4M 100 11 312 800 MWWM 100 2 14 800 MWwM 100 4 is 60SI-1852 28 500 MDH4M 100 2 19 500 MDH,&M 100 4 19 500 MDH4M 100 11 19 250 MDH4M. 100 2 13 250 MDH4M 100 4 13 250 MDH4M 100 11 13 Notes to Table 4 1. DH. is a cyclic hydride composed of hydrogenmethylsiloxyl units where x ranges from 4 to 6 and MM is hexamethyldisiloxane. 21 No further approach to equilibrium with the addition of more UNC catalyst 3. Silicon-29 NMR was indicative of incorporation of both vinyl and hydride species in the copolymers formed.

60SI-1852 29 Cl 9

Claims

Having described the invention that which is claimed is

1. A process for the production of siloxane copolymers comprising:

(a) selecting a hydrogen rich siloxane having an active hydrogen content above about 0.100 mole percent active hydrogen; and (b) polymerization of a cyclic siloxane and said hydrogen rich siloxane in the presence of a catalytic Lewis acid compound producing thereby a copolymeric siloxane.

2. The process of claim 1 wherein the catalytic Lewis acid compound is a phosphonitrilic compound selected from the group consisting of 1) (X3P(NPX2).PX3)-PX6- where n is an integer of from 1 to 6 and X is a halide; 2) (X3P(NPX2),,NPX3)'IPX6- where n is an integer of from 1 to 6 and X is a halide; 3) (X3P(NPX2)nNPX3)+EXm- where E is an element having an electronegativity value of from 1.2 to 2 with m an integer of from 3 to 8 and X is a halide; 4) O(X)2-aYaP(NPX2)bNPX3-CYC where b is an integer ranging from 0 to 8, a is 0 or 1, c is 0 or 1, Y is OH, OR' or R'CO2 where R! is alkyl or aryl and X is a halide; 5) O(X)2-ayaP(NPX2)bNP(O)X2-cyc where b is an integer ranging from 0 to 8, a is 0 or 1, c is 0 or 1, Y is OH, OR' or R'CO2 where R'is alkyl. or aryl and X is a halide; 6) X3-p(HO)pP(NPX2)MNP(O)X2, where m is an integer ranging from 0 to 6 and p is 0 or land X is a halide; and 7) X3P(NPX2)mNPX2(0) where m values can vary from 0 to 6 and X is a halide. 3. The process of claim 2 where X is selected from the group consisting of F, Cl, Br, and L 60SI-1852 30 4. The process of claim 3 where E is selected from the group consisting of AI, Sh, P, Sn, Zn and Fe.

5. The process of claim 4 where the phosphonitrilic compound has the formula (X3P(NPX2)J)(3)+M.

6. The process of claim 5 where n = 27. The process of claim 6 where X is Cl.

8. The process of claim 7 where the hydrogen rich siloxane has the formula:

MD1,.DHpM where M has the formula R4R5R6SiOi12 with R4, R5 and R6 are each independently selected from the group consisting of hydrogen and one to forty carbon atom monovalent hydrocarbon radicals, D has the formula SiR'RX)/2with R' and R2 independently selected from hydrogen and one to forty carbon atom monovalent hydrocarbon radicals, DH has the formula SiR'HC/2with R' independently selected from hydrog" and one to forty carbon atom monovalent hydrocarbon radicals, the subscript p is 1 or greater 10 and the subscript a is either 0 or independently assumes the same values as P.

9. The process of clahn 8 further comprising an M rich sfioxane compound.

10. A process for the production of siloxane copolymers consisting essentially of- (a) selecting a hydrogen rich siloxane having an active hydrogen content above about 0.100 mole percent hydrogen; and (b) polymerization of a cyclic sfioxane and said hydrogen rich siloxane in the presence of a catalytic Lewis acid compound producing thereby a copolymeric siloxane.

60SI-1852 31 11. A silicone polymer having the formula: M.Dq, having at least two Dq where each Dq is different from every other Dq and each Dq has the formula: 5 Dq = SMIR20212 where each R' and R2 in each Dq is independently selected from the group consisting of hydrogen and one to forty carbon atom monovalent hydrocarbon radicals where each subscript q of D. is independently one or greater with M = R4R5R6SiQ/2where R4, R5 and R6 are each independently selected from the group consisting of hydrogen and one to forty carbon atom monovalent hydrocarbon radicals, where the stoichiometric subscript u of M is non- zero and positive; subject to the limitation that one of R', R2, R4, RS, and R6 is hydrogen and that one of R, R2, R4, Rs, and R6which is, not hydrogen is an is alkenyl group having from two to forty carbon atoms. 12- The polymer of claim 11 where one of R4, Rs, and R6 is an alkenyl group having from two to forty carbon atoms. 13. The polymer of claim 11 where one of R4, Rs, and R6 is hydrogen. 14. The polymer of claim 11 where one of R' and R2 is an alkenyl group having from two to forty carbon atoms. 15. The polymer of claim 11 where one of R' and R2is hydrogen. 16. The polymer of claim 11 comprising a first Dqwhere one of R' and R2 is hydrogen and a second D. where one of R' and R2is an alkenyl group having from two to forty carbon atoms. 17. The polymer of claim 11 where R7 is hydrogen. 18. The polymer of clabn 11 where R7 is an alkenyl groups having from two to forty carbon atoms.

60SI-1852 32 19. The polymer of claim 16 where one of R4, Rs, and R6 is an alkenyl group having from two to forty carbon atoms. 20. The polymer of claim 16 where one of R4, R-5, and R6is hydrogen. 21. A silicone polymer having the formula: M.Dq# having at least two Dqwhere each Dq is different from every other Dq and each Dq has the formula: Dq = SiRIR20212 where each R' and R2 in each D,, is independently selected from the group consisting of hydrogen and one to forty carbon atom monovalent hydrocarbon radicals where each subscript q of Dq is independently one or greater with M. = R4R5R6SiO12 where R4, R5 and R6 are each independently selected from the group consisting of hydrogen and one to forty carbon atom monovalent hydrocarbon radicals where the stoichiometric subscript.u of M is nonzero and positive; subject to the limitation that one of R, R2, R4, RS, and R6 is hydrogen and that one of R, R2, R4, Rs, and R6which is not hydrogen is an is yl group having from two to forty carbon atoms produced by the process of claim 1.