Abstract: Organic-inorganic composite particles which include a (meth)acrylic resin framework and a polysiloxane framework having in its molecule an organosilicon containing a silicon atom directly and chemically combined with at least one carbon atom of the (meth)acrylic resin framework, and also contain 25 wt % or more of SiO.sub.2 which constitutes the polysiloxane framework and have a mean particle diameter of .gtoreq.0.5 .mu.m. The particles have the mechanical resilience necessary to maintain a constant gap distance between a pair of members to be arranged with the correct gap distance between them, and the hardness and fracture strength necessary to maintain the gap constant with smaller numbers; and also do not readily cause physical damage to the members. The composite particles can be employed as spacers 8 for a liquid crystal display as they stand or, with an adhesive layer formed on the surface.

Abstract: Copolysiloxanecarbonates are prepared in the melt by the reaction of a diaryl carbonate such as diphenyl carbonate with a mixture of a dihydroxyaromatic compound and a carbonate-terminated polydiorganosiloxane, the latter typically prepared by reaction of a diaryl carbonate or aryl chloroformate with a hydroxyorgano-terminated polydiorganosiloxane. By this method, incorporation of silicone units in the copolysiloxanecarbonate is maximized.

Abstract: The invention relates to oxide particles which have a surface modification by covalently bonded organic groups which allow covalent bonding into polymer materials. These particles are particularly advantageous in their use as fillers or modifying agents in polymer materials, in particular polymer films.

Abstract: Improved silicone-containing hydrogels are disclosed with enhanced wettability comprising a silicone-containing monomer, at least one acrylic-containing hydrophilic monomer, and at least one vinyl-containing hydrophilic monomer.

Abstract: Organosiloxane copolycondensates are disclosed and which are optionally cross-linked by means of cross-linking agents containing Si, Ti, Zr and/or Al and contain the units ##STR1## wherein R.sup.1 -R.sup.5 are ##STR2## wherein R.sup.6 is alkylene with C.sub.1 -C.sub.10 bound directly to N or X, cycloalkylene with C.sub.5 -C.sub.8 or ##STR3## X is >N--H, >N--CH.sub.3, >N--C.sub.2 H.sub.5, --S--, --S.sub.2 --, --S.sub.3 --, --S.sub.4 --, ##STR4## wherein R" is H or alkyl with C.sub.1 -C.sub.5. These products are in the form of spherical particles with a diameter of 0.01 to 3.0 mm, a specific surface of up to 1000 m.sup.2 /g, a specific pore volume of up to 6.0 ml/g and a bulk density of 50 to 1000 g/l. Different methods of preparing the formed copolycondensates are disclosed as well as use of certain compositions for removing metals from solutions and/or for the adsorption of gaseous organic compounds and/or of water vapor.

Abstract: A siloxane gum is prepared by adding a silane or siloxane having two hydrolyzable groups in a molecule to a silanol-terminated organopolysiloxane in such an amount to give a molar ratio of silanol group/hydrolyzable group of from 0.5 to 3 and effecting condensation polymerization. The resulting organopoly-siloxane has a degree of polymerization of higher than 1,000 and a minimized content of low-molecular weight cyclic siloxanes of less than 5,000 ppm.

Abstract: There is disclosed a novel organopolysiloxane-grafted polybenzobisoxazole and a method for preparing the functional organopolysiloxane-grafted polybenzobisoxazoles using a phthaloyl halide-functional organopolysiloxane.

Abstract: Proposed is an improved radiation-curable organopolysiloxane composition capable of giving a cured surface film on a substrate surface which exhibits excellent releasability against sticky substances. The composition is obtained by combining two kinds of (meth)acryloxyalkyl-containing organopolysiloxanes in a specified weight proportion, of which one has a relatively large degree of polymerization but contains only a relatively small amount of the silicon-bonded (meth)acryloxyalkyl groups while the other has a relatively small degree of polymerization but contains a relatively large amount of the silicon-bonded (meth)acryloxyalkyl groups.

Abstract: The introduction of a room-temperature-curable organopolysiloxane composition that cures at room temperature to give a rubber whose surface is easily coated with paint and from which the resulting paint film does not delaminate readily and that after curing is free from staining of the surface of the rubber and any substrates in contact with the rubber.

Abstract: A crosslinkable composition comprising (A) an organopolysiloxane which has at least one monovalent SiC-bonded radical containing primary and/or secondary amino groups, and (B) a crosslinking component selected from an alkoxysilane and/or siloxane which contains at least one carboxylic acid anhydride group. The crosslinkable composition and/or the resultant organopolysiloxane compound obtained from the reaction of organopolysiloxane (A) and crosslinking component (B) can be used to treat organic fibers and textile structures produced therefrom.

Abstract: A thermosetting powder composition which comprises (a) a specific a carboxyl-terminated polyester and (b) a glycidyl group-containing acrylic copolymer. The carboxyl-terminated polyester (a) has an acid number of 15 to 70 mg of KOH/g and must be prepared in two steps. In the first step, a hydroxyl-terminated polyester is prepared from at least one polycarboxylic acid other than 1,4-cyclohexanedicarboxylic acid, and at least one aliphatic or cycloaliphatic polyol and in the second step, the resulting hydroxyl-terminated polyester is esterified with 1,4-cyclohexanedicarboxylic acid exclusively. In addition, the composition of the polyester (a) is very specific: it contains at least 75 mole % of terephthalic acid, at least 10 mole % of 1,4-cyclohexanedicarboxylic acid and at most 14 mole % of at least one other aromatic and/or aliphatic and/or cycloatiphatic polycarboxylic acid, based on a total carboxylic acid content of 100 mole %.

Abstract: This invention relates to polysiloxanes having fluoroaliphatic- and carboxyl- containing terminal groups, their preparation and their use in imparting water-, oil- and soil-repellency and a soft hand to fibrous substrates such as leather, and to the resulting treated substrate.

Abstract: Self-adhesive silicone compositions having (A) an organopolysiloxane of the following average unit equation (1)(R.sup.1).sub.z --SiO.sub.(4-z)/2 (1)wherein R.sup.1 is either a substituted or an unsubstituted monovalent hydrocarbon group and Z is a number in the range from 1.98 to 2.01 having a viscosity at 25.degree. C. of at least 300 cSt,(B) an organic silicon compound which possesses at least one group expressed by the following equation (2) within the molecule: ##STR1## wherein R.sup.2 is a substituted or an unsubstituted monovalent hydrocarbon group, R.sup.3 and R.sup.4 are either a hydrogen atom, methyl group, or an ethyl group, and n is an integer of 0, 1, or 2, and(C) an organic peroxide. The silicone compositions strongly adhere onto various materials such as metals and plastics without the need of primer treatments.

Abstract: A room temperature curable fluorine-containing organopolysiloxane composition comprising:(A) a fluorine-containing organosilicon compound having the general formula (1):R.sup.2 --NHCO--[Rf--CONH--R.sup.1 --Q--R.sup.1 --NHCO].sub.a --Rf--CONH--R.sup.2 (1)wherein a is an integer of 0 or more, Rf is a divalent perfluoroalkylene group or a divalent perfluoropolyether group, R.sup.1 is a divalent hydrocarbon group, R.sup.2 is a monovalent aliphatic unsaturated group-containing hydrocarbon group, and Q is a divalent siloxane group(B) a hydrogenorganopolysiloxane containing at least two Si--H groups in its molecule, and(C) a platinum family metal catalyst. The cured product of this composition exhibits good solvent resistance against non-polar solvents as well as polar solvents, in addition to good chemical resistance, heat resistance, release properties and water repellency.

Abstract: A polyimidesilicone resin precursor composition which comprises a polysiloxane of the following general formula ##STR1## wherein R is a monovalent organic group having up to 10 carbon atoms, R.sup.1 represents a hydrogen atom or a monovalent organic group having up to 10 carbon atoms, and m is an integer not smaller than 3, and a polyamic acid or a polyimide obtained from the polyamic acid. The composition is cured at a relatively low temperature within a short time to provide a cured film having improved solvent and heat resistances and good adhesion to various substrates.

Abstract: A polydimethylsiloxane which has both low reactivity endgroups and high reactivity endgroups. These polydimethylsiloxanes are useful for making sealants with reduced modulus. An example of these polydimethylsiloxanes is one having low reactivity endgroups of the formulaZR.sub.2 SiO--where Z is alkoxy, acyloxy, or N-methylbenzamido, and R is methyl or vinyl and high reactivity endgroups having a formulaY'.sub.h Y.sub.b R".sub.(3-b-h) SiO--in which b is 1, 2, or 3, h is 0 or 1, b+h is 2 or 3, R" is a monovalent hydrocarbon radical, and each Y is an acyloxy groups or N-methylbenzamido, and Y' is an alkoxy groups.

Abstract: Fully alkoxysilane-functionalized aliphatic polyamine compounds (e.g., fully functionalized dialkylenetriamine compounds) can be formed by reacting a dialkylenetriamine (e.g., diethylenetriamine) with a compound comprising an amine-reactive group and an alkoxysilane group (e.g., an isocyanatoalkylalkoxysilane). These functionalized compounds find utility as the predominant component in forming organic/inorganic hybrid materials via sol-gel processing.

Abstract: Vulcanizable organopolysiloxane compositions comprise a hydroxy-terminated organopolysiloxane, an acrylic or methacryllc functional alkoxy silane, a divalent tin compound, an alkoxy-.alpha.-silyl ester, a photopolymerization initiator, and a curing catalyst whereby the composition is cured by UV irradiation and/or by the action of moisture in air. The composition has good shelf stability and can yield rubber elastomers having good physical properties.

Abstract: A diorganopolysiloxane terminated only at one of the molecular chain ends with a (meth)acryloxyalkyl group bonded to the terminal silicon atom is prepared, instead of the prior art method in which a diorganopolysiloxane obtained by the anionic ring-opening living polymerization reaction of, for example, hexamethyl cyclotrisiloxane by using a lithium catalyst is subjected to a desalinating condensation reaction with a (meth)acryloxyalkyl dimethyl chlorosilane, by a novel method in which the diorganopolysiloxane obtained by the anionic ring-opening living polymerization reaction of, for example, hexamethyl cyclotrisiloxane is hydrolyzed and the thus obtained monofunctionally silanol-terminated diorganopolysiloxane is reacted with a (meth)acryloxyalkyl dimethyl dialkylamino silane to effect a deamination reaction.

Abstract: A stable aqueous dispersion having a particle size in the range of about 10 to about 200 nanometers containing specific silanes carrying at least one hydrophobic moiety and at least one water-solubilizing moiety is claimed along with the process for treating a cellulosic substrate and the treated cellulosic product resulting therefrom. The aqueous dispersions are stable for at least 20 days without externally added surfactant.

Abstract: A novel curable polyimide resin of structural formula (1) or (2) is provided wherein R.sup.1 and R.sup.2 are independently substituted or unsubstituted monovalent C.sub.1-10 hydrocarbon groups, R.sup.3 is a divalent C.sub.1-10 organic group, X is a tetravalent organic group containing an aromatic or aliphatic ring, Y is a divalent organic group, Z is a divalent organic group containing an aromatic ring, W is a trivalent organic group containing an aromatic ring, m is an integer of 1 to 3, and n is an integer of at least 1. It can be prepared by reacting a polyimide with a silicon compound. The curable resin forms with a solvent a solution having a low viscosity and shelf stability and cures at relatively low temperatures below 300.degree. C. into coatings having heat resistance, mechanical strength, electrical properties, solvent resistance and substrate adherence.

Abstract: Crosslinkable copolymers suitable for use as elevated temperature pressure-sensitive adhesives comprise randomly arranged silarylene units and siloxane units. Preferably, there is present in the copolymer backbone in the range of 0.8 to 1.2 siloxane to silarylene units, and there being present in the copolymer a crosslinking functionality.

Abstract: A room-temperature curable epoxy resin composition is disclosed. The composition contains (a) a resin component containing a polyepoxide function and an alkoxysilyl function, and (b) as a curing catalyst an amine, amide or urea salt of a superacid. The composition find its use in coating compositions, adhesives, sealants or potting compounds and casting compositions.

Abstract: A curable composition comprising an oxyalkylene polymer having a silicon-containing hydrolyzable group and a low-molecular silicon compound having a hydrolyzable group bonded to a silicon atom which is more reactive to H.sub.2 O than the oxyalkylene polymer, with the mole number of the total hydrolyzable groups in said low-molecular silicon compound being not more than that of the hydrolyzable groups in said oxyalkylene polymer. A sealing compound having well-balanced storage stability and rapid curability is provided.

Abstract: An organoalkoxysilane/metal oxide sol-gel composition and method for its production are disclosed whereby an organoalkoxysilane of the general formulaR.sub.x Si(OR').sub.4-xwherein R is an organic radical, R' is a low molecular weight alkyl radical, and x is less than 4 and may be zero, is partially hydrolyzed in organic solution and reacted with a titanium alkoxide of the general formula Ti(OR'').sub.4 wherein R'' is a lower alkyl radical. The composition is hydrolyzed, dried and heat treated to form a silicon oxide/titanium oxide abrasion-resistant coating on a substrate with high ultraviolet radiation absorbance.

Abstract: A process for the preparation of sulfonated silicones is disclosed. The process comprises the steps of (a) hydrosilylating an olefin-terminal silylketene acetal with a hydrosiloxane; (b) treating the ketene acetal with a trialkylsilylsulfonyl chloride and (c) hydrolyzing the resulting .alpha.-trialkylsilyl ester to provide a salt of an .alpha.-sulfonate. Useful products of the process are also disclosed; they comprise several genera of .alpha.-sulfonate esters pendant from siloxanes and polysiloxanes. The products are useful as polymer electrolytes and as sustained or controlled release substrates for the administration of medicines.

Abstract: A condensation-curing type curable composition which comprises a diorganopolysiloxane or polyoxyalkylene blocked by hydrolyzable silyl group at both terminal ends of its molecular chain as a base polymer, in which a carbonyl group-containing organic compound and an amino group-containing organic compound are compounded. This composition is capable of forming water through dehydration condensation between carbonyl and amino groups, simultaneously with curing of the composition by moisture in air. The formation of water offers marked improvements in fast-curing property and also in depth curing property.

Abstract: Novel curable siloxane polymers having integral ultra-violet light absorbers are disclosed which are useful in preparing a variety of commercial silicone products requiring excellent resistance to loss of UV protection due to external forces.

Abstract: Siliconimides, which contain cross-linkable, functional groups, having the general formula ##STR1## in which the Q residues contain the functional groups.

Abstract: Polymeric stabilizers with a polysiloxanic structure contain sterically hindered phenol groups and reactive groups capable of binding themselves to the polymeric structure to be stabilized. These polymeric stabilizers are particularly suitable for applications which require the non-extractability of additives due to solvents, fats or soaps.

Abstract: The invention relates to a series of novel silicone alkoxylates a process for their preparation and the application of these materials as emulsifiers for a variety of oil phases. This class of compounds are prepared by the reaction of a carboxy functional silicone and a ethylene oxide, propylene oxide or mixtures thereof. The products provide unique surfactant properties, specifically emulsification properties for many oil phases.The compounds are useful for preparation of ultra mild products for use personal care applications for skin, hair care and related applications.

Abstract: Imide-containing phthalonitrile monomers are prepared from a phthalonitrile and an aromatic dianhydride. The monomer and a method for preparing the monomer is disclosed. These monomers are synthesized into heat resistant polymers and copolymers with aromatic ring structure incorporating imide and ether linkages. The synthesis of the high temperature thermosetting polymers and copolymers is also disclosed.

Abstract: The present invention relates to a release coating composition comprising (a) about 1 to about 100 percent by weight of a particular polysiloxane polymer (I), (b) about 0 to about 99 percent by weight of a silane of a particular formula (II) or hydrolyzates thereof, and (c) about 1 to about 15 percent by weight of a component selected from the group consisting of acids, anhydrides of acids, ammonium and lower alkyl salts of acids and mixtures thereof wherein the acids each have pKas of less than about 3.

Abstract: A curable resin composition comprising a mixture or cocondensate of a compound containing imide and alkoxysilyl groups and an organosilane or organopolysiloxane is shelf stable and cures into a film which is improved in heat resistance, mechanical strength, electrical properties, solvent resistance and adhesion to substrates and thus suitable as a protective film on electronic parts.

Abstract: Organofunctional siloxanes useful in a wide variety of personal care and plastics applications are disclosed having a carboxyalkylaminoalkyl functionality.

Abstract: Organosilicon compounds with a siloxane portion and groups of the general formula --OR'OCH.dbd.CHR'' (i) linked via an Si--O--C bond, wherein R' is a divalent hydrocarbon radical or a group --R.degree.--(OR.degree.).sub.n --, wherein R.degree. is alkylene and n is from 1 to 12, R'' is H or alkyl are useful in radiation curable compositions, in which they are mixed with an initiator. The compositions are particularly useful in UV radiation curable relase coatings.

Abstract: Improved permanent soft denture liners are disclosed which consist substantially of an amount of one or more polysiloxanes selected from acryloxyalkyl and methacryloxyalkyl-terminated polydialkylsiloxanes in which the polysiloxane is crosslinked by a material selected from suitable heat, light or chemically activated initiators with or without crosslinking agents. The preferred embodiments are visible light activated and can be applied, fitted, cured and installed in one sitting.

Abstract: There is described an organopolysiloxane which contains at least 2 amino groups, carboxyl groups, hydroxyl groups, or epoxy-functional organic groups at one and only one molecular chain terminal, as well as a method for the preparation of same. The organopolysiloxane has the formula ##STR1## wherein R is a monovalent hydrocarbon group which is free of aliphatically unsaturated bonds and wherein the groups R may be identical or different; A' is selected from the group consisting of groups, the carboxyl group, the hydroxyl group, and epoxy-functional organic groups; B is the same or a different divalent organic group having at least 2 carbon atoms; m is zero or one; and n is an integer with a value of zero to 200.

Abstract: A room temperature vulcanizable silicone rubber composition is provided, comprising (A) an organopolysiloxane containing at least one amino group represented by --R.sup.1 NH.sub.2 in a molecule and having a viscosity of from 25 to 500,000 cst at 25.degree. C. wherein R.sup.1 is a divalent C.sub.1-20 hydrocarbon group or a divalent C.sub.1-20 organic group containing an ether bond or --NH-- bond, (B) an organic silicon compound of the formula: OCNR.sup.2 SiR.sub.a.sup.3 X.sub.3-a wherein R.sup.2 has the same meaning as R.sup.1, R.sup.3 is a monovalent C.sub.1-10 hydrocarbon group, X is an alkoxy, ketoxime, alkenyloxy or acyloxy group, and a is 0 or 1, and (C) a curing catalyst. The composition cures at room temperature, providing a product having improved heat resistance, weather resistance and adhesion.

Abstract: Liquid crystal polymers containing 0.1 to 0.9 mole % of repeating units bing a mesogenic side group and 0.1 to 0.9 mole % of repeating units which do not bear a mesogenic side group in which the mesogenic side group has the formula:--(CH.sub.2).sub.n O--R.sub.1 --X--R.sub.2R.sub.1 is 1,4-phenylene or 4,4'-biphenylene;X is --COO-- or --OCO--;R.sub.2 is ##STR1## wherein k is 0 or 1, * indicates an optically active center;Z is NO.sub.2, F, or Cl;R.sub.3 is C.sub.l H.sub.2l+1, --*CH(CH.sub.3)C.sub.p H.sub.2p+1 --CH.sub.2 C.sub.q F.sub.2q+1, --*CH(CH.sub.3)COOC.sub.t H.sub.2t+1 (wherein l and p are each independently an integer of from 1 to 10 and q and t are each independently an integer of from 1 to 6); and n is an integer of 4 to 12;exhibit fast response times.

Abstract: The present invention is characterized by adding and mixing an organosilicon compound having alkoxy, groups and an ester linkage in the molecule represented by the following formula: ##STR1## in an amount of 1 to 20 parts by weight per 100 parts by weight of a trifluoropropylalkylpolysiloxane. Said organosilicon compound has a function as a storage stabilizer as well as a curing agent and, according to the present invention, an RTV fluorosilicone composition that has hitherto been difficult to be applied as an adhesive for electric and electronic parts has been made possible to be used in the particular field.

Abstract: Silicone rubber compositions based on an organopolysiloxane are improved in release properties by blending a silane having both a fluorinated hydrocarbon group and an alkanoyloxy group and/or an organopolysiloxane having an alkanoyloxy or alkanoyloxyalkyl group.

Abstract: New, thermooxidatively stable polyimides have been prepared from the reaction of aromatic dianhydrides containing isopropylidene bridging groups with aromatic diamines containing amide connecting groups between the rings. Several of these polyimides were shown to be semi-crystalline as evidenced by wide angle xray scattering and differential scanning calorimetry. Most of the polyimides form tough, flexible films with high tensile properties. These polyimide films exhibit enhanced solubility in organic solvents.

Abstract: Silicone-polycarbonate block copolymers are provided resulting from the reaction of certain siloxy aromatic imide siloxanes or hydroxyaromatic ester siloxanes which are made by effecting reaction between an organosiloxane having terminal aromatic anhydride groups or aromatic haloacyl groups which are each attached to silicon by silicon arylene linkages with an appropriate bishydroxyarylene compounds or hydroxyarylene amino compound. The aforementioned hydroxyaromatic imide siloxanes or hydroxyaromatic ester siloxanes are then phosgenated with a dihydric phenol or an aromatic bischloroformate. The silicone-polycarbonate block copolymers have been found to be flame retardant and useful as dielectric films and membranes, and as flame retardants in aromatic polycarbonates.

Abstract: Disclosed is a polyimide ammonium salt comprising the reaction product of an ethylenically unsaturated amine with an aromatic polyimide having pendant carboxylic acid groups, said polyimide comprising the reaction product of diamine and aromatic dianhydride, where the diamine comprises an aromatic carboxylic acid diamine having at least one carboxylic acid. A substrate can be coated with the polyimide ammonium salt by forming a composition of a crosslinking agent and a solution of the polyimide salt in an organic solvent, spreading the composition on the substrate, evaporating the solvent to form a coating, exposing at least some of the coating to actinic radiation to crosslink and insolubilize the exposed portions of the coating, and washing the unexposed portions away by dissolving them in an organic solvent.

Abstract: A coating composition having improved abrasion resistance is provided, which comprises (A) a composition comprising (1) an organooxy-chainstopped organopolysilsesquioxane, (2) a tetraorganotitanate, (3) (a) a siloxane-functionalized ester having the general formula (R.sup.3 O).sub.3-2n SiO.sub.n R.sup.4 OC(O)R.sup.5 C(O)OR.sup.6, wherein n is equal to 0, 1/2, or 1, each R.sup.3 is independently a saturated or unsaturated monovalent hydrocarbon radical containing from 1 to about 20 carbon atoms, R.sup.4 is a divalent hydrocarbon radical containing from 1 to about 20 carbon atoms, R.sup.5 is a divalent conjugated olefinic radical having from 2 to 4 carbon atoms, and R.sup.6 is R.sup.3 or R.sup.4 SiO.sub.n (OR.sup.3).sub.3-2n ; or (b) a cyanoorganotriorganooxysilane: and (4) an organic carboxylic acid ester; and (B) from 0% to about 85% of a volatile diluent.

Abstract: An N-substituted polyamide-imide essentially composed of identical or different repeating units of the formula I ##STR1## where R.sup.1 is one of the following tetravalent aromatic radicals ##STR2## and X is a bond or one of the following linkers ##STR3## where R.sup.2 and R.sup.4 are each, independently of one another, one of the following divalent aromatic radicals ##STR4## and where X has the abovementioned meanings and where R.sup.3 is hydrogen or a monovalent radical such as C.sub.1 -C.sub.6 -alkyl or phenyl, and the C.sub.1 -C.sub.6 -alkyl-, C.sub.1 -C.sub.6 -alkoxy-, aryl- or halogen-substituted derivatives thereof, and precursors (monomers) therefor, are described.

Abstract: A process for synthesizing polyestercarbonate-siloxane copolymers which have a smaller concentration of low molecular weight species and greater thermal stability has been described. Essentially the process includes adding the comonomer, diacid chloride siloxane, after approximately 1/3 of the phosgene has been added, in a conventional interfacial copolymerization, (as opposed to addition at the beginning of the polymerization).

Abstract: Organopolysiloxanes having polyether and ester groups linked to a common spacer group, wherein the spacer group is linked through an SiC bond to the siloxane backbone and a method for the synthesis thereof are disclosed. These compounds are useful as additives for plastics, lacquers and binders for reducing the coefficient of sliding friction, for improving scratch resistance and increasing abhesiveness. If the compounds are esters of acrylic or methacrylic acid, they can be used as radiation-curable lacquers and coating compositions.

Abstract: An improved method for the preparation of very high molecular weight polycarborane siloxane polymers in which each of the reactants is first provided in an ultra-pure state by a series of recrystallization procedures in specific solvents. The reactants are then reacted in the following series of steps by:(a) providing ultra-pure carborane bisdimethyl silanol in dried chlorobenzene solvent, to form a slurry and cooling said slurry to -10.degree..+-.5.degree. C.;(b) adding to said slurry a mixture of ultra-pure dimethylbisureido silane and ultra-pure methylphenylbisureido silane to form a reaction mixture at -10.degree..+-.5.degree. C.