摘要:
Organosols of organopolysiloxanes are prepared by adding water-soluble organic solvents or mixtures thereof or water-soluble mixtures of water-soluble and water-insoluble organic solvents to aqueous, colloidal suspensions of organopolysiloxanes obtained by adding at least one alkoxysilane and/or the partial hydrolyzate thereof, and, if appropriate, mixed with an organo(poly)siloxane free of alkoxy groups and having a maximum of 8 siloxane units per molecule, to water in the presence of emulsifiers at a maximum rate of 5 moles of organosilicon compound per hour and per liter of water, and subsequently removing the water by distillation.
摘要:
Silicone resin powders are obtained by spray drying aqueous colloidal suspensions of organopolysiloxanes which are prepared by adding an alkoxysilane and/or a partial hydrolysate thereof and, if appropriate, mixed with an organo(poly)siloxane which is free of alkoxy groups and contains a maximum of 8 siloxane units per molecule, to water in the presence of an emulsifier at a maximum rate of 5 moles of organosilicon compound per hour per liter of water.
摘要:
Colloidal suspensions of organopolysiloxanes are prepared by mixing an organosilicon compound selected from the group consisting of mixtures of alkoxysilanes and/or partial hydrolysates thereof and an organo(poly)siloxane which is optionally free of alkoxy groups and contains a maximum of 8 siloxane units, which is mixed with at least one alkoxysilane and/or a partial hydrolysate thereof, with water in the presence of an emulsifier, at a maximum rate of 5 moles of organosilicon compound per hour per liter of water, in which the organosilicon compound and the water is fed continuously, but separately from one another, into a reactor, in which at least one of the two substances contains an emulsifier, while the alkanol is being continuously removed by distillation from the aqueous suspension continuously emerging from the reactor. The aqueous suspension from which the alkanol has been removed by distillation is, if desired, recycled back into the reactor. A tubular reactor is preferably employed in which the water is added continuously at, or near the upper end of the tubular reactor and the organosilicon compound is added via several inlet points arranged along the longitudinal axis of the tubular reactor.
摘要:
Previously cross-linked silicone elastomer particles with an organic-polymer shell are used as constituents for formulating aqueous coating compositions based on water-soluble or water-dilutable binders. The silicone elastomer particles contain: (a) 5 to 95% by weight, with respect to the total weight of the copolymer, of a nuclear polymer of general formula (R.sub.2 SiO.sub.2/2).sub.x (RSiO.sub.3/2).sub.y (SiO.sub.4/2).sub.z, in which x=5 to 99.5% by mole, y=0.5 to 95% by mole, z=0 to 30% by mole, and (b) 5 to 95% by weight, with respect to the total weight of the copolymer of a shell made of an organopolymer from mono- or poly-ethylenically unsaturated monomers; and R stands for the same or different monovalent alkyl or alkenyl radicals with 1 to 6 carbon atoms, aryl radicals or substituted hydrocarbon radicals.
摘要:
Process for the preparation of an organopolysiloxane resin, which comprisesin a first stage reacting at least one silane of the formulaR.sub.a Si(OR.sup.1).sub.4-a (I)in which a has a value of 0, 1, 2 or 3, R and R.sup.1 are monovalent organic radicals which may be the same or different and/or a partial hydrolyzate thereof, with the proviso that at least one silane of formula (I), where a is 0 or 1 and/or a partial hydrolyzate thereof is employed, and optionally an organo(poly)siloxane with water in the presence of a poly-protic acid and optionally other substances, subsequently partly neutralizing the acid by addition of a base and then distilling off at least some of the compound R.sup.1 OH formed,in a second stage reacting the homogeneous reaction mass resulting from the first stage in the presence of a base and a water-insoluble organic solvent and distilling off the water and the compound R.sup.1 OH,in a third stage, bringing the homogeneous reaction mass resulting from the second stage to a pH of between 6 and 8 by buffering with a poly-protic acid and/or salts thereof, distilling off the water and any compound R.sup.1 OH still present and filtering off the salt which has precipitated, andoptionally, in a fourth stage separating the homogeneous reaction mass resulting from the third stage from the water-insoluble organic solvent.
摘要:
A process for preparing organopolysiloxane hydrosols by mixing an organosilicon compound with water, which comprises mixing a silane of the formulaR.sub.a Si(OR.sup.1).sub.4-a (I)where a is 0, 1, 2 or 3, R can be the same or different and is a hydrogen atom or a monovalent organic radical, R.sup.1 can be the same or different and is a monovalent organic radical, and/or a partial hydrolysis product thereof and, optionally, an organodisiloxane of the formulaR.sup.2.sub.3 Si-O-SiR.sup.2.sub.3 (II)where R.sup.2 can be the same or different and is the same as R, with water in the presence of an emulsifier at a temperature below 15.degree. C.
摘要:
The invention relates to crosslinked organopolysiloxanes which contain groups which form free radicals and are built up from units of the formula[R.sub.a Si(O.sub.(3-a)/2)-R.sup.1 -X-(R.sup.1 -Si(O.sub.(3-a)/2)).sub.b R.sub.a ] (1),in whichX is a radical from the group consisting of --N.dbd.N--, --O--O--, --S--S-- and --C(C.sub.6 H.sub.5).sub.2 --C(C.sub.6 H.sub.5).sub.2 --, andR is monovalent SiC-bonded, optionally substituted C.sub.1 - to C.sub.18 -hydrocarbon radicals,R.sup.1 is divalent SiC-bonded, optionally substituted C.sub.1 - to C.sub.18 -hydrocarbon radicals which can be interrupted by divalent radicals, bonded to carbon atoms on both sides, from the group consisting of --O--, --COO--, --OOC--, --CONR.sup.2 --, --NR.sup.2 CO-- and --CO--,R.sup.2 is a hydrogen atom or a radical R,a has the values 0, 1 or 2 andb has the values 0 or 1,and further organosiloxane units. The organopolysiloxanes are used as free radical macroinitiators for grafting polymerization of ethylenically unsaturated monomers.
摘要:
A process for preparing organopolysiloxanes having SiC-bonded organofunctional groups, which comprises reacting an organopolysiloxane containing SiC-bonded hydroxyl and/or alkoxy groups and having an average of about 0.85 to 1.8 SiC-bonded monovalent hydrocarbon radicals or halogenated monovalent hydrocarbon radicals for each Si atom, with an organosilicon compound containing alkoxy groups and/or siloxane oxygen groups and at least one SiC-bonded organofunctional radical per molecule in the presence of an organic solvent and a basic catalyst.The resultant organopolysiloxanes having SiC-bonded organofunctional groups may, for example, be used for preparing modified polymers by copolymerizing the organopolysiloxanes with a monomer containing an aliphatic double bond, such as styrene or hydroxyethyl methacrylate, or by reacting the organopolysiloxanes with an additional polymer such as an epoxy resin. When a monomer, containing an aliphatic double bond is used in the copolymerization, the resultant modified polymers may be used to manufacture hard contact lenses.
摘要:
The invention relates to compounds of the formula[RSiO.sub.3/2 ].sub.z (I)in whichz is 6, 8 or 10;R represents the same or different radicals of the formulas--CH.sub.2 CH.sub.2 --X (II), --CH(CH.sub.3)--X (III) or --O--Si(R'.sub.2)--Y (IV) with the proviso that up to z-1 of the radicals can also be radicals of the formula --O--SiR'.sub.3, in which X represents a monovalent radical or one half of a divalent radical of the formulas ##STR1## R' represents the same or different C.sub.1 - to C.sub.6 -alkyl, C.sub.1 - to C.sub.6 -alkoxy or phenyl radicals;R" represents the same or different C.sub.1 - to C.sub.18 -alkyl radicals, which can be substituted by radicals of formulas (V) or (VI);R'" represents the same or different divalent C.sub.1 - to C.sub.18 -hydrocarbon radicals, preferably alkylene and/or phenylene radicals and/or radicals of the formula--(R'.sub.2 SiO).sub.n --;Z represents a halogen atom or an N-bonded amino radical, that is an NH.sub.2 radical, an N-piperidinyl, n-piperazinyl or N-morpholinyl radical or a C.sub.1 - to C.sub.6 -N-monoalkylamino or a C.sub.1 - to C.sub.6 -dialkylamino radical;Y represents a hydrogen atom, an optionally halogenated C.sub.2 - to C.sub.10 -hydrocarbon radical or a radical of the formulas (II) or (III); andn represents an integer having avalue of at least 1.
摘要:
Substrates which are exposed to weathering are coated with paints containing an epoxy resin and a silicon compound containing basic nitrogen which is bonded to the silicon via a carbon and which has at least one hydrogen atom bonded directly to the nitrogen atom.