- Addition cross-linking two-component silicone materials with a high Shore D hardness
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The present invention relates to an addition-cross-linking two component silicone material containing one or more organopolysiloxanes having at least two vinyl groups in the molecule, at least one cross-linking agent and at least one catalyst, wherein the material contains more than 1 wt %, relative to the total quantity of the two-component silicone material, of at least one organopolysiloxane of general formula I [in-line-formulae]CH2═CH—SiR1R2O—(SiR1R2O)n—SiR1R2—CH═CH2,[/in-line-formulae]in which R1 and R2 are identical or different and are selected from the group comprising alkyl groups, aryl groups, aralkyl groups, halogen-substituted alkyl groups, halogen-substituted aralkyl groups, cyanoalkyl groups, cycloalkyl groups and cycloalkenyl groups, and n is an integral number between 1 and 9, as well as to the use of this silicone material.
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- Preparation of branched siloxane
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By reacting a branched siloxane compound of formula (2) containing compounds of formula (1) as an impurity with a disiloxane compound of formula (3) in the presence of an acid compound, there is prepared a branched siloxane of formula (2) containing a reduced level of compounds of formula (1).R1?nSi(OSiR2?3)3-n(OR3)R1?nSi(OSiR2?3)4-nR2?3SiOSiR2?3 R1 is a monovalent hydrocarbon group, R2 and R3 are H or monovalent hydrocarbon groups, and n is 0 or 1.
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Page/Page column 15
(2010/02/10)
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- Process for preparing organosiloxanes
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Organosiloxanes (1) of the general formula in which R is the same or different and represents a hydrogen atom or a monovalent hydrocarbon radical having from 1 to 18 carbon atom(s) per radical or a substituted monovalent hydrocarbon radical having from 1 to 18 carbon atom(s) per radical, R1 represents R or a chlorine atom, and n is 3 or 4, are prepared by reacting organodisiloxanes (2) of the general formula with chlorosilanes (3) of the general formula in which R and n are the same as above, in the presence of phosphonitrile chlorides (4) and cocatalysts (5), in which the cocatalysts (5) are used concomitantly with the phosphonitrile chlorides (4) and are selected from the group consisting of amides of the general formula in which R2 is the same or different and represents a hydrogen atom or a monovalent hydrocarbon radical having from 1 to 8 carbon atom(s) per radical or a substituted monovalent hydrocarbon radical having from 1 to 8 carbon atom(s) per radical, and X reresents a radical of the formula R22 N- or STR1 where R2 is the same as above, R3 represents a divalent hydrocarbon radical having from 5 to 7 carbon atoms per radical, urea or urea derivatives of the general formula where X is the same as above and cyanuric acid.
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