Abstract: The present invention relates to a process for the production of an intermediate siloxane monomer and use of said monomer to produce high molecular weight linear polysilalkylenesiloxanes. The siloxane monomer is prepared by ring opening polymerization of a cyclic monomer of the structure in the presence of an acidic or basic ring opening polymerization catalyst; to form a mixture of siloxane monomers and linear oligomers. The linear oligomers are then extracted and discarded before a further step of ring opening polymerization using the aforementioned intermediate siloxane monomer mixture as the starting material. The second polymerization step is undertaken at a temperature within the melting point range of said siloxane monomer mixture. The intermediate, final product and methods of their manufacture are described.

Abstract: A process for the production of non-thermoplastic polyimide film whose precursor solution has high storage stability and which exhibits high adhesiveness even without expensive surface treatment, more specifically, a process for the production of non-thermoplastic polyimide film made of a non-thermoplastic polyimide containing a block resulting from a thermoplastic polyimide which comprises (A) the step of forming a prepolymer having amino or an acid anhydride group at the end in an organic polar solvent (B) the step of synthesizing a polyimide precursor solution by using the obtained prepolymer, an acid anhydride, and a diamine in such a way as to become substantially equimolar over the whole step, and (C) the step of casting a film-forming dope containing the polyimide precursor solution and subjecting the resultant dope to chemical and/or thermal imidization, wherein the diamine and acid dianhydride used in the step (A) are selected so that the reaction of both with each other in equimolar amounts can give

Abstract: An amino alkoxy-modified silsesquioxane (AMS) comprising one or more compounds selected from the group consisting of an amino AMS, an amino/mercaptan co-AMS, an amino/blocked mercaptan co-AMS, mixtures thereof, and a weak acid-neutralized solid or aqueous solution thereof, and a method of making the amino AMS, are presented. The compounds are useful in compounding, processing, cure and storage of silica-reinforced rubbers because they contain low levels of volatile organic compounds (VOC).

Abstract: A method is presented for making an amino alkoxy-modified silsesquioxane (amino AMS) comprising one or more compounds selected from the group consisting of an amino-AMS, an amino/mercaptan co-AMS, an amino/blocked mercaptan co-AMS, and mixtures of these. The use of solid strong cationic catalysts in this reaction system is advantageous because the catalyst remains as a solid throughout the reaction, allowing simplified separation of the solid catalyst from the soluble amino AMS or amino co-AMS products, resulting in total or near total recovery of the amino AMS or amino co-AMS products, as well as virtual total recovery of the catalyst for recycling. The use of the solid strong cationic catalysts is advantageous because it results in amino AMS products that are free of, or substantially free of, residual acid catalyst.

Abstract: The present invention relates to a process for the continuous preparation of mixtures containing organosilicon compound (A) and solid (B) and optionally further components in a mixing unit comprising at least one rotating mixing shaft, wherein at least one mixing shaft makes an angle of inclination with the horizontal of more than 10 degrees and the inlet opening for the solid (B) is arranged higher than the outlet opening.

Abstract: A corrosion protection composition includes a mixture of three different silanes selected to interact and form a coating on metal substrates that has improved adhesion and durability as well as UV protection properties. Methods of manufacturing the corrosion protection composition include mixing the silanes together and further combining the silane mixture with other mixtures to arrive at the corrosion protection composition. Sonication may be a preferred manner of mixing together the various components of the mixtures.

Abstract: Organopolysiloxanes containing both acidic and basic groups are prepared by reacting oganopolysiloxanes with primary or secondary amino groups with a stoichiometric deficiency of isocyanates containing sulfonyl-group-containing electron withdrawings groups in the presence of acidic or basic moderators.

Abstract: A method for preparing an organopolysiloxane compound by mixing (A) an organopolysiloxane of the formula (1): wherein R1 is a monovalent hydrocarbon group and may be the same or different, R is a divalent hydrocarbon group, and n is an integer of at least 2, with (B) an organic compound of the formula (2) or (3): wherein R2 is H or a monovalent hydrocarbon and R3 is a divalent hydrocarbon and (C) an organic compound of the formula (4): wherein R1 and R3, respectively, have the same meanings as defined above, R4 is a monovalent hydrocarbon group, and p is 0 or 1, wherein components (A), (B) and (C) are reacted with one another under conditions that a ratio between an amino group equivalent PNH in component (A) and an isocyanate group equivalent PNCO in components (B) and (C) is such that 0.8?(PNCO/PNH) and a molar ratio between component (B) and component (C) is such that 0.6?[component (B)/component (C)].

Abstract: Disclosed herein is an adhesive composition for transporting a flexible substrate, which is used to manufacture a flexible display device using a flexible substrate such as a plastic substrate by using a conventional line for manufacturing a liquid crystal display device comprising a glass substrate. The present invention provides an adhesive composition for transporting a flexible substrate, which includes 100 parts by weight of an adhesive for transporting a flexible substrate and 0.001 to 5 parts by weight of an antistatic agent, an adhesive sheet containing the composition, and a method of transporting a flexible substrate using the same.

Abstract: The present invention relates to an organopolysiloxane composition that can be vulcanized at room temperature into an elastomer that is crosslinked by polycondensation and that does not contain alkyltin-based catalysts and also to novel organopolysiloxane polycondensation catalysts.

Abstract: The invention provides a process for preparing liquid, branched SiH-functional siloxanes by reacting a mixture of one or more low molecular weight SiH-functional siloxanes, one or more low molecular weight SiH-free siloxanes, one or more tetraalkoxysilanes, and optionally one or more trialkoxysilanes with addition of water and in the presence of a Brønsted-acidic ion exchanger, which is characterized in that the reaction is performed in one process step.

Abstract: Disclosure herein are methods of preparing cross-linked silicone polymers by contacting a silicone polymer and optionally a cross-linking agent with a hydrolytic enzyme under conditions for the cross-linking of the silicone polymer, wherein the silicone polymer has been modified to comprise functional groups that react with the hydrolytic enzyme.

Abstract: This invention relates to acrylic functional resin compositions. More particularly, this invention relates to Poly [organ-co-(meth)acryloxyorgano]silsequioxane resins that are curable upon exposure to ultraviolet radiation with photo initiator or upon heating with or without a free radical generator. The resin compositions have high storage stability at room temperature and produces films that are useful as planarization layer, interlayer dielectric, passivation layer, gas permeable layer, negative photoresist, antireflective coating, conformal coating and IC packaging.

Abstract: An antifouling condensation curing organopolysiloxane composition is prepared by premixing a part or all of (A) a diorganopolysiloxane free of a reactive group with a part or all of (B) silica to form a premix, then mixing the premix with the remainder of (A) and (B), (C) a base diorganopolysiloxane, and (D) a silane. The composition has a good balance of low viscosity and high thixotropy, can be thickly coated in a single pass, and cures into a coating having rubber strength and surface smoothness and exhibiting satisfactory antifouling property over a long period of time.

Abstract: A method of preparing a diluted chain extended organopolysiloxane containing polymer comprising the steps of reacting a pre-formed polymer with a suitable chain extender reactable with terminal groups of the polymer in the presence of a diluent material, a suitable catalyst and optionally an end-blocking agent; and Where required quenching the polymerization process wherein the diluent material is substantially retained within the resulting diluted organopolysiloxane containing polymer. The case additionally relates to products of the process and subsequent applications for the polymer such as for example sealants and rubbers.

Abstract: A silicon-containing polymer which is represented by general formula (5) below and has a weight-average molecular weight in the range from 500 to 500,000: (In the formula, A2 is an organic group of 2-10 carbons, having a carbon-carbon unsaturated group; R3 is an alkylene group of 1-20 carbons, a bivalent aromatic group of 6-20 carbons, or a bivalent alicyclic group of 3-20 carbons; n is 0 or 1; R4 is a hydrogen atom or an alkyl group of 1-10 carbons (R4 in one molecule may be the same type or a combination of two or more different types.); each of x and y is a positive number; each of w and z is 0 or a positive number; 0?z/(w+x+y)?2; and 0.01?y/(w+x)?5), and the heat-resistant resin composition comprising the silicon-containing polymer.

Abstract: A curable resin composition which is easily cured by heating or ultraviolet irradiation and capable of forming a thick cured film due to low shrinkage. This curable resin composition enables to obtain a cured product satisfying various characteristics such as heat resistance, chemical resistance, high surface hardness and high refractive index. Also disclosed is a cured product obtained from such a composition.

Abstract: Present invention provides a fluorine-containing organopolysiloxane composition comprising a fluorine-containing silicone polymer having a three-dimensional, cross-linked structure, prepared by addition polymerizing the following (A), (B) and (C) and containing 10 to 30 mass % of the fluorine atoms, relative to a total mass of (A) to (C), (A) a vinyl group-containing organopolysiloxane represented by the following formula (1): (B) an organohydrogenpolysiloxane represented by the following formula (2): and (C) an organopolysiloxane having a reactive group on one end alone and represented by the following formula (3), and further comprising (D) a low viscosity silicone oil with a dynamic viscosity of 50 mm2/s or less at 25 degrees C.

Abstract: The present invention relates to a process for the production of an intermediate siloxane monomer and use of said monomer to produce high molecular weight linear polysilalkylenesiloxanes. The siloxane monomer is prepared by ring opening polymerization of a cyclic monomer of the structure in the presence of an acidic or basic ring opening polymerisation catalyst; to form a mixture of siloxane monomers and linear oligomers. The linear oligomers are then extracted and discarded before a further step of ring opening polymerization using the aforementioned intermediate siloxane monomer mixture as the starting material. The second polymerisation step is undertaken at a temperature within the melting point range of said siloxane monomer mixture. The intermediate, final product and methods of their manufacture are described.

Abstract: Process for producing an organosiloxane polymer and novel organosiloxane polymer compositions. The process according to the invention comprises hydrolyzing tetraalkoxysilane monomers in a hydrolysis step; and polymerizing said hydrolyzed monomers in a polymerization step by subjecting them to conditions conducive to polymerization to form an organosiloxane polymer. The hydrolysis step is conducted in a reaction medium comprising an organic compound with hydroxy groups. The invention allows for the synthesis of siloxane polymer compositions suitable for thin-film applications using a high content of tetra- and trifunctional silixane polymer precursors.

Abstract: The invention provides a process for preparing liquid, branched SiH-functional siloxanes by reacting a mixture of one or more low molecular weight SiH-functional siloxanes, one or more low molecular weight SiH-free siloxanes, one or more tetraalkoxysilanes, and optionally one or more trialkoxysilanes with addition of water and in the presence of a Brønsted-acidic ion exchanger, which is characterized in that the reaction is performed in one process step.

Abstract: The present invention relates to a process for producing a particulate nanocomposite material, in which the particles of the nanocomposite material comprise a) at least one inorganic or organo(semi)metallic phase which comprises at least one (semi)metal M; and b) at least one organic polymer phase. The invention also relates to the nanocomposite materials obtainable by this process. The process comprises the polymerization of at least one monomer MM which has at least one first cationically polymerizable monomer unit A which has a metal or semimetal M, and at least one second cationically polymerizable organic monomer unit B which is joined to the polymerizable unit A via at least one, e.g.

Abstract: Organopolysiloxanes are prepared in a multistage process by a first partial hydrolysis with from 0.002 to 0.6 mol water per hydrolyzable chlorine and alcohol at a water to alcohol ratio of 0.001 to 1.5, then further hydrolyzing with additional water, and then separating an aqueous alcoholic phase from an organopolysiloxane phase.

Abstract: A synthetic process for polyhedral oligomeric silsesquioxanes (POSS) and polyhedral oligomeric silicates (POS) produces silanol and siloxide molecules containing both olefinic groups and alkyl or aromatic groups. Olefin-bearing POSS silanol/siloxides are derivatized into a variety of chemical species while retaining the ability to further derivatize the silanol/siloxide.

Abstract: A method of preparing a diluted chain extended organopolysiloxane containing polymer comprising the steps of reacting a pre-formed polymer with a suitable chain extender reactable with terminal groups of the polymer in the presence of a diluent material, a suitable catalyst and optionally an end-blocking agent; and Where required quenching the polymerization process wherein the diluent material is substantially retained within the resulting diluted organopolysiloxane containing polymer. The case additionally relates to products of the process and subsequent applications for the polymer such as for example sealants and rubbers.

Abstract: The invention relates to the use of organofunctional carboxy compounds as catalysts for silane hydrolysis and/or catalysts for silanol condensation, wherein according to the invention, the term carboxy compounds refers to an organic acid, preferably an organic carboxylic acid with 4 to 46 carbon atoms, such as fatty acids, or an organic acid precursor compound containing silicon, an ?-carboxysilane ((R3—(CO)O)4-z-xSiR2x(A)z, ?-Si-oxycarbonyl-R3), or an organic acid precursor compound which does not contain silicon. The term organic acid precursor compound means esters, lactones, anhydrides, salts of organic cations. The invention also relates to the use of at least one organofunctional carboxy compound for the surface modification of substrates, the substrates modified with the same, and a kit for use in the production of the substrate.

Abstract: Fluoride catalyzed rearrangement reactions of polymeric silsesquioxanes [RSiO1.5]n involve reacting at least one silsesquioxane material with a catalytic amount of an organic fluoride at a temperature ranging from about ?50° C. to about 120° C. thereby forming a reaction mixture for a period ranging from 60 minutes to 48 hours. To the reaction mixture, a quenching agent is added to remove fluoride from the reaction mixture. A silsesquioxane cage compound can be isolated from the reaction mixture using a precipitation or other extraction process.

Abstract: A mixture of a benzophenone derivative having hydroxyl and alkoxysilyl groups and a benzophenone derivative having silyloxy and alkoxysilyl groups provides a reactive UV absorber which is unlikely to gel, stable during shelf storage, and curable. A coating solution comprising the UV absorber cures at room temperature to form a UV-screening film which has adhesion to glass and plastic substrates, scratch resistance, and bleed resistance, and maintains a UV-screening function over time.

Abstract: A novel multi-functional linear siloxane compound, a siloxane polymer prepared from the siloxane compound, and a process for forming a dielectric film by using the siloxane polymer. The linear siloxane polymer has enhanced mechanical properties (e.g., modulus), superior thermal stability, a low carbon content and a low hygroscopicity and is prepared by the homopolymerization of the linear siloxane compound or the copolymerization of the linear siloxane compound with another monomer. A dielectric film can be produced by heat-curing a coating solution containing the siloxane polymer which is highly reactive. The siloxane polymer prepared from the siloxane compound not only has satisfactory mechanical properties, thermal stability and crack resistance, but also exhibits a low hygroscopicity and excellent compatibility with pore-forming materials, which leads to a low dielectric constant.

Abstract: The present invention relates to the use of tocopherol as a co-catalyst in the ring opening polymerisation of cyclic siloxanes. The present invention further relates to a method for manufacturing hydrophilic polysiloxanes, wherein a hydrido-containing cyclic siloxane is reacted with a hydrophilic molecule comprising a carbon-carbon double bond, having the general formula (I) H2C?CH—(CHR)n—O—(CHR1CR2R3)mR4 or (II) H2C?CH—(CHR)n—R5, wherein n is an integer from 0 to 4, m is an integer from 0 to 5, R, R1, R2, R3 and R4 are each independently hydrogen or a C1 to C6 alkyl, R5 is a saturated cyclic hydrocarbon containing carbonyl group, in the presence of a first catalyst to obtain a monomer, and polymerising said monomer in the presence of a second catalyst and tocopherol as a co-catalyst.

Abstract: A method of making a diluted organopolysiloxane polymer comprising the steps of:— (i) preparing an organopolysiloxane polymer by polymerizing cyclic organopolysiloxane monomer(s) in the presence of an organic diluent material, a suitable catalyst and an end-blocking agent; and (ii) Where required quenching the polymerization process; wherein the diluent material is substantially retained within the resulting diluted organopolysiloxane.

Abstract: A hydrophilic composition contains (A) a hydrophilic polymer represented by the following general formula (I); and (B) an alkoxide compound of an element selected from Si, Ti, Zr and Al: wherein the symbols in the formula are defined in the specification.

Abstract: A method for hydrolyzing/condensing, by acid catalysis, silanes bearing hydrolyzable groups, preferably halogenosilanes and more preferably still chlorosilanes, in a polyphase reaction medium (preferably biphasic), includes contacting the silanes bearing the hydrolyzable groups with water, buffer solution and neutralizing agent, while stirring, then in separating the aqueous phase from the organic phase, which contains the hydrolysis/condensation products, namely hydroxylated polyorganosiloxanes; such method is characterized by (a) employing intensively stirring means producing, in the reaction medium, an agitation at least equivalent to that induced by a shearing corresponding to that provided by a rotor whereof the peripheral speed is not less than 8 m.s?1, preferably not less than 10 m.s?1, and more preferably still ranging between 15 and 20 m.s?1, enabling thus organic phase droplets to be formed, of d32 less than 500 ?m; and (b) ensuring that the silanes/aqueous phase mass fraction is not less than 0.

Abstract: The invention relates to a dental composition comprising a) carbosilane containing component (A) comprising at least 1 Si-Aryl bond, at least 1 silicon atom, at least 2 Si—H functional moieties, no Si-Oxygen bond, b) unsaturated component (131), and/or epoxy component (132), c) initiator (C), d) optionally filler (D) and e) optionally component (E) selected from modifiers, dyes, pigments, thixotropic agents, flow improvers, polymeric thickeners, surfactants, odorous substances, diluting agent(s) and flavorings.

Abstract: The present invention provides a curable composition including: an organic polymer (A) which has on average 1.1 to 50 groups per one molecule thereof each represented by the general formula (1) and has one or more silicon-containing functional groups capable of cross-linking by forming siloxane bonds: —NR1—C(?O)—??(1) wherein R1 is a hydrogen atom, or a substituted or unsubstituted monovalent organic group; and a metal carboxylate and/or a carboxylic acid (B), the curable composition giving a cured article excellent in curability and also excellent in heat resistance although a non-organotin catalyst is used.

Abstract: A process for producing a low VOC epoxy silane oligomer which includes hydrolyzing an epoxy silane, the epoxy silane upon hydrolysis of its hydrolyzable sites producing a reduced amount of volatile organic compound compared to that produced by the hydrolysis of a silane possessing an equivalent number of hydrolyzable sites all of which are hydrolyzable alkoxy groups, the hydrolyzing of the epoxy silane being carried out with less than 1.5 equivalents of water, said water being continuously fed during the hydrolysis reaction.

Abstract: Particles with a structural surface which are useful to produce abrasion resistant self-cleaning surfaces contain particulate solid particles having a superstructured overlayer of fine particles. The particles may be prepared by polymerizing a polymerizable siloxane, silane, or mixture thereof in a Pickering emulsion.

Abstract: A silicone resin composition for die bonding is provided. The composition includes (A) a straight-chain organopolysiloxane having silicon-bonded alkenyl groups, and with a viscosity of no more than 1,000 mPa·s, (B) a three dimensional network-type organopolysiloxane resin that is either wax-like or solid at 23° C., (C) an organohydrogenpolysiloxane having SiH groups, and (D) a platinum-group metal-based catalyst. The composition produces a cured product with a high hardness, and good heat resistance, transparency, and light transmittance in the low wavelength region.

Abstract: The invention relates to, and the general field of the invention is that of, the synthesis of silicone resins, more particularly the synthesis of silicone resins of type MQ. The process relates to the preparation of MQ silicone resins and permits better control of the operating conditions in the step of the polymerization of a sodium silicate (B) in aqueous medium in the presence of an acid (C) to form a silica hydrosol (polysilicic acid). In the course of the polycondensation step the reactants, a sodium silicate and an acid, are mixed, preferably in continuous fashion, dynamically to form a mixture (3), by means of at least one intensive mixing tool (M) producing a power ? per unit volume of more than 10 kW/m3.

Abstract: A method is presented for making alkoxy-modified silsesquioxanes (AMS) or co-alkoxy-modified silsesquioxanes (co-AMS,) comprising the steps of (a) combining as a reaction mixture (i) water, (ii) an acid-stable solvent for the water, (iii) a solid strong cationic hydrolysis and condensation catalyst, and (iv) a trialkoxysilane compound, (b) allowing the reaction mixture to react for about 0.5 hours to about 200 hours to form the alkoxy-modified silsesquioxanes; and (c) recovering the alkoxy-modified silsesquioxanes from the reaction mixture. The use of solid strong cationic catalysts in this reaction system is advantageous because they remain as solids throughout the reaction, allowing simplified separation of the solid catalyst from the soluble AMS or co-AMS products, resulting in total or near total recovery of the AMS or co-AMS products, the products being free of, or substantially free of residual acid catalyst, as well as virtual total recovery of the catalyst for recycling.

Abstract: A method for preparing a polyorganosiloxane which is sold at 25° C. and has R13SiO0.5 units wherein R1 is a hydrocarbon group having 1 to 10 carbon atoms and SiO2 units, said method comprising the steps of: [1] subjecting at least one selected from an organosilane and an organodisiloxane, and at least one selected from a tetralkoxysilane and a partial condensate of hydrolysates of the tetralkoxysilane to hydrolysis reaction and condensation reaction in the presence of an acidic catalyst; [2] adding a liquid aliphatic hydrocarbon; and subsequently [3] separating a liquid aliphatic hydrocarbon phase and an aqueous phase and then removing said aqueous phase; provided that the step [2] may be performed before, during, or after the step [1].

Abstract: A process for forming a composition comprising organosilsesquioxanes, comprises the following steps: 1. partially hydrolysing hydrolysable inorganic monomer precursors comprising at least 50 mole % of first hydrolysable inorganic monomer precursors having the formula RSiY3, in which R is an organic group, the R—Si bond is a non-hydrolysable bond, each Y group is the same as or different to one another and is selected from chemically-reactive groups such that each Si—Y bond is hydrolysable to form a Si—OH bond, to form inorganic monomers and allowing partial condensation of the inorganic monomers to form a liquid composition comprising inorganic oligomers; 2.

Abstract: A process for producing a low VOC epoxy silane oligomer which includes hydrolyzing an epoxy silane, the epoxy silane upon hydrolysis of its hydrolyzable sites producing a reduced amount of volatile organic compound compared to that produced by the hydrolysis of a silane possessing an equivalent number of hydrolyzable sites all of which are hydrolyzable alkoxy groups, the hydrolyzing of the epoxy silane being carried out with less than 1.5 equivalents of water, said water being continuously fed during the hydrolysis reaction.

Abstract: A process for producing an epoxy silane oligomer including a reaction glycidoxy silane and/or cycloaliphatic epoxy silane having 2 or 3 alkoxy groups and, optionally, a copolymerizable silane other than glycidoxy and cycloaliphatic epoxy silane, with less than 1.5 equivalents of water in the presence of a catalyst, wherein said water is continuously fed during the reaction.

Abstract: The invention relates to coating agents, containing (A) at least 50 wt. %, (in relation to the content of non-volatile substances in said coating agent), of at least one compound (A1) and/or (A1?) comprising at least two reactive groups of formula (I): —X—SiR?x(OR?)3-x, in which R?=hydrogen, alkyl or cycloalkyl, whereby the carbon chain can be interrupted by non-adjacent oxygen, sulphur or NRa groups, Ra=alkyl, cycloalkyl, aryl or aralkyl, X=a linear and/or branched alkene or cycloalkene group comprising between 2 and 20 carbon atoms, R?=alkyl, cycloalkyl, aryl or aralkyl, whereby the carbon chain can be interrupted by non-adjacent oxygen, sulphur or NRa groups, and x=0 to 2, (B) a catalyst for cross-linking the —Si(OR?)3-x units, and (C) an organic solvent or a mixture of organic solvents.

Abstract: Novel silicone polyether copolymers of inverse structure of the formula 1, characterized in that no unsaturated functional groups caused by side reactions or conversion products thereof are present in the copolymer, and a process for preparation thereof, in which a polyether modified terminally and/or laterally with alkoxysilyl groups is reacted with silanes and/or siloxanes which bear one or more hydrolysis-labile groups, in a hydrolysis and condensation reaction.

Abstract: Novel compositions, as well as related methods, coatings, and articles, are disclosed.

Abstract: A curable silicone composition comprising: (A) an organopolysiloxane that has a branched molecular structure and contains in one molecule at least two univalent hydrocarbon groups with phenolic hydroxyl groups therein; (B) a linear-chain organopolysiloxane having at least two univalent hydroxyl groups with epoxy groups that are free of aromatic rings; and (C) a curing accelerator.

Abstract: A method of forming a preceramic polymer includes treating a silane precursor having a vinyl moiety of ammonia to produce the preceramic polymer. For example, the silane precursor is trichlorovinylsilane. The preceramic polymer may then be cross-linked at a relatively low temperature by using a cross-linking agent.

Abstract: A siloxane resin having the formula: (HSiO3/2)a(RSiO3/2)b(SiO4/2)c where R is Z, Z(CH2)n or ZO(CH2)n where Z is a phenyl or substituted phenyl group; n has a value of 1 to 6, a has value of 0.01 to 0.7, b has a value of 0.05 to 0.7, c has a value of 0.1 to 0.9 and a+b+c?1. The siloxane resins are useful in anti-reflective coating compositions.