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:
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:
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:
The present invention relates to siloxane copolymers containing alkenyl groups and a process for their preparation. The siloxane copolymers of the present invention can be used in cross-linkable compositions for the production of coatings which repel tacky substances, an example of which would include coatings for release papers or films.
摘要:
The organopolysiloxane particles consist of a single molecule, are crosslinked and have an average diameter of 5 to 200 nm. At least 80% of the particles have a diameter which deviates from the average diameter by not more than 30%. The particles are soluble in a solvent to the extent of at least 5% by weight.
摘要:
An epoxy resin molding material comprising an epoxy resin, a phenolic resin and a powder flexibilizer which has a core-shell structure composed of a solid silicone core and an organic polymer shell is a reliable epoxy resin molding material for sealing electronic parts which is excellent in, for example, thermal shock resistance and reflow soldering resistance, and is free from the troublesome deterioration in, for example, the appearance and marking properties of molded products, and to provide a semiconductor sealed by the molding material.
摘要:
The invention relates to aqueous emulsions containing (A) organo-hydrogenated polysiloxanes optionally mixed with organopolysiloxanes free of Si linked hydrogen and organyloxy groups, (B) organopolysiloxanes containing organyloxy groups as stabilizers, (C) emulsifiers and (D) water.
摘要:
The aqueous emulsions based on(a) 100 parts by weight of organopolysiloxanes which contain polar groups on Si--C-bonded hydrocarbon radicals and(b) not more than 50 parts by weight of alkyl polyglycosides which are stable toward high concentrations of foreign electrolytes.
摘要:
The invention relates to the use of precrosslinked silicone elastomer particles with an organopolymer shell as the formulation constituent in powder coating material compositions based on thermoplastic or thermosetting binding agents, the silicone elastomer particles containing (a) 5 to 95% by weight, in relation the total weight of the copolymerisate, of a nucleus polymer of the general formula (R.sub.w SiO.sub.2/2).sub.x.(RSiO.sub.3/2).sub.y.(SiO.sub.4/2).sub.z with x=5 to 99.5 mol %, y=0.5 to 95 mol %, z=0 to 30 mol %, and (b) 5 to 95% by weight, in relation to the total weight of the copolymer, of a shell made of an organopolymer of ethylenically mono or multi-unsaturated monomers, R standing for identical or different monovalent C.sub.1 -C.sub.6 alkyl or alkenyl residues or substituted hydrocarbon residues.
摘要:
The invention relates to the preparation of organopolysiloxane microemulsions, wherein the components (A) organopolysiloxane, (B) emulsifier, (C) water, optionally, (D) cosurfactant and optionally (E) acid are brought together and mixed in any desired sequence. Microemulsions are formed spontaneously without introduction of energy in the form of heat or severe shearing forces.