Abstract: A moisture curable composition capable of cure to an elastomeric body comprising (a) a diluted polymer comprising (i) a silicon containing polymer of the formula X-A-X1 where X and X1 are independently selected from silyl groups which contain one or more condensable substituents per group and A is a polymeric chain having a number average molecular weight (Mn) of at least 132 000; and a degree of polymerisation of at least 1800. (ii) an organic extender and/or plasticiser which diluted polymer is obtained by polymerisation in the presence of the said organic extender and/or plasticiser (b) a suitable cross-linking agent which comprises at least two groups which are reactable with the condensable groups in the diluted polymer, (c) a suitable condensation catalyst and optionally (e) one or more fillers.

Abstract: A polysiloxane having a refractive index of about 1.56 measured at light wavelength 633 nm, characterized in that the polysiloxane includes siloxane T units of the formula where A represents an alkylene group having 1 to 4 carbon atoms: n=0 or 1; m is at least 1; and Ar is an aryl group substituted by at least one iodine, bromine or chlorine atom, or is a polynuclear aromatic group. The invention includes chlorosilanes having the formula (Ar) m-(A)nSiCl3, useful in forming high refractive index polysiloxanes.

Abstract: A method for pacifying the spent bed material resulting from the synthesis of organohalosilanes and halosilanes by mixing clay with spent bed material. Clay compositions containing at least 10 weight % of clay and spent bed material, as well as ceramic compositions containing spent bed material, are also provided.

Abstract: A silane or siloxane containing at least one organic group is prepared by a hydrosilylation reaction between a silane or siloxane (A) containing at least one Si—H group and an allyl compound (B) in the presence of a noble metal catalyst. The silane or siloxane (A) and the allyl compound (B) are fed continuously through a reaction zone which is maintained at a temperature in the range 115–200° C. and which is provided with heat exchanger means to dissipate the heat from the exothermic hydrosilylation reaction. The residence time of (A) and (B) in the reaction zone is less than 20 minutes.

Abstract: The invention provides composite components, structures and method for producing composite components A composite component has a negative effective Poisson's ratio and comprises a first component and a second component. The first component and the second component extend longitudinally relative to an axis, the first component being provided around the second component through one or more turns which are spaced longitudinally relative to the axis. A variation in the tensile load on the first component causes the radial position of the second component relative to the axis to vary.

Abstract: A crosslinked polysiloxane comprises polysiloxane chains substituted by an ester-containing organic moiety joined by crosslinks derived from the reaction of an alpha, omega-diunsaturated hydrocarbon or fluorohydrocarbon with Si—H groups on the polysiloxane chains. The ester-containing organic moiety has the formula -A-COOR where A is an alkylene linkage having 1–18 carbon atoms which is optionally fluoro-substituted and R is an alkyl or fluoroalkyl group. The crosslinked polysiloxane can form an elastomeric gel in a liquid organic or silicone material, which is useful in preparing cosmetics.

Abstract: This invention provides methods for making ceramic articles with improved density, compression strength and efflorescence properties, in which a pre-ceramic article containing direct process residue gel is heated at an elevated temperature.

Abstract: A branched siloxane contains at least three aliphatically unsaturated hydrocarbon groups, is terminated by units of the formula RaRb2SiO1/2 and otherwise consists of: i) one or more units of the formula(SiO4/2); and ii) from 15 to 995 units of the formula Rb2SiO2/2 which units (i) and (ii) may be inter-linked in any appropriate combination. The invention includes a method of making the branched siloxane and release coating and release modifier compositions containing the branched siloxane.

Abstract: An elastomer-forming coating composition for textile fabrics comprises a first, second and third organopolysiloxane having aliphatically unsaturated substituents, an organosilicon crosslinker having at least 3 silicon-bonded hydrogen atoms, a catalyst and a reinforcing filler. First and second organopolysiloxanes have only terminal aliphatically unsaturated substituents, first having a viscosity at 25° C. of from 50 to 650 mm2/s, second a viscosity at 25° C. of at least 10,000 mm2/s and third organopolysiloxane has aliphatically unsaturated substituents at terminal siloxane units and on siloxane units in the siloxane polymer chain. Coated textile fabrics and a process for making them is also claimed. Coated fabrics are especially useful in applications where they form a barrier between areas of differing pressures, e.g. airbags. Resulting coatings combine very good tear strength and elongation at break values.

Abstract: Siloxanes are polymerized by equilibration, condensation and/or ring-opening polymerization using a phosphazene base catalyst. A linear phosphazene base catalyst of the general formula wherein R denotes a C1-10 hydrocarbon or wherein two R groups on one N atom form with the N atom a heterocyclic group, X denotes an anion and n is from 1 to 10 is prepared by reacting a linear phosphonitrile halide compound with a secondary amine or a salt of a secondary amine or a metal amide thereof to form an aminated phosphazene material, followed by an ion exchange reaction replacing the anion with a nucleophile.

Abstract: A curable coating composition which exhibits improved cure and adhesion to various substrates comprises a composition curable by a hydrosilylation reaction and includes a silicone resin, a hydrosilylation reaction inhibitor and an adhesion promoting additive which comprises an organosilicon compound having epoxy and alkoxy functionalities, an alkenylsilanol, an organotitanium compound and a metal chelate compound.

Abstract: A polymerization process comprising mixing a siloxane having silicon-bonded groups R′ and a cyclic or linear siloxane having no silicon-bonded groups R′ with a phosphazene base catalyst in the presence of water and allowing the siloxane having silicon-bonded groups R′ to condense and the cyclic or linear siloxane having no silicon-bonded R′ groups to polymerize by equilibration.

Abstract: Phosphonitrile halides are prepared employing the use of disilazanes. The resultant products may be further reacted with cyclosiloxanes to form siloxane containing phosphonitrile halides.

Abstract: A polymerization process comprising mixing siloxane polymers with organosilicon compounds having at least one silicon-bonded group RN, which is a substituent comprising at least one amine group, and with a phosphazene base catalyst and allowing the siloxanes and organosilicon compounds to polymerize to form amino-functional polyorganosiloxane polymers is claimed.

Abstract: A polymerization process comprising mixing siloxanes having silicon-bonded groups R′ with ionic phosphazene base catalysts and allowing condensation via reaction of Si—R′ groups with the formation of a Si—O—Si linkage, R′ denoting a hydroxyl group or a hydrocarbonoxy group having up to 8 carbon atoms is claimed. The catalysts may be of the general formulae: {((R12N)3P═N—)x(R12N)3−xP—N(H)R2}+{A−} or {((R12N)3P═N—)y(R12N)4−yP}+{A}− in which R1 is hydrogen or an optionally substituted hydrocarbon group or in which two R1 groups bonded to the same N atom may be linked to complete a heterocyclic ring, R2 is hydrogen or an optionally substituted hydrocarbon group, x is 1, 2 or 3, y is 1, 2, 3 or 4 and A is an anion.

Abstract: A method for selective electroless metal deposition on a substrate. The method comprises applying a patterned coating comprising a silyl hydride functional resin onto a substrate. An electroless plating solution comprising a metal ion is then applied onto the silyl hydride functional resin coating to deposit a patterned metal film on the substrate. The process of the invention is especially useful in the electronics industry.

Abstract: A continuous process for producing a silicone polymer comprises the sequential steps of (i) polymerisation of a linear silanol group containing siloxane by condensation polymerisation, or of a cyclosiloxane by ring opening polymerisation, or of a mixture of said linear and cyclosiloxanes with a phosphazene base in the presence of water and the presence or absence of a filler in an extruder, (ii) neutralising the reaction mixture in an extruder, and (iii) stripping the neutralised reaction mixture to remove volatile materials. Preferably, step (iii) is performed in an extruder, more preferably steps (i), (ii) and (iii) are all performed in the same extruder.

Abstract: A continuous process for producing a silicone polymer comprises the sequential steps of (i) polymerisation of a linear silanol group containing siloxane by condensation polymerisation, or of a cyclosiloxane by ring opening polymerisation, or of a mixture of said linear and cyclosiloxanes with a phosphazene base in the presence of water and the presence or absence of a filler in a static mixer, (ii) neutralising the reaction mixture in a static mixer, an in-line mixer or an extruder, and (iii) stripping the neutralised reaction mixture to remove volatile materials. Preferably step (ii) is performed in a static mixer and step (iii) is performed in a thin film stripper, extruder or co-rotating processor.

Abstract: A compound of formula (I) is disclosed for use as a silylating agent: ##STR1## wherein each R.sup.1 is independently a hydrogen atom, an alkyl group or an alkenyl group with at least one R.sup.1 being a hydrogen atom or alkenyl group, and R.sup.2 is a hydrogen atom or an alkyl group. Also disclosed is a method of making the compound, and a method of using the compound as a silylating agent.

Abstract: A method for the preparation of a hydrophobic clay by contacting an aqueous suspension of the clay with an organosilane of formula R.sup.1.sub.a SiX.sub.4-a or an organosiloxane comprising units of formula R.sup.2.sub.n SiO.sub.(4-n)/2 in the presence of an acid and a water-miscible solvent. The resulting clay suspension is then contacted with a water-immiscible solvent to effect separation of the hydrophobed clay from the suspension.