Process for the preparation of organopolysiloxanes modified with methacrylic esters
AssigneeTh. Goldschmidt AG
InventorVaclav Kropac
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Abstract
A method for preparation of organopolysiloxanes suitable for use as binders in hardenable compositions of polymerizable monomers, the organopolysiloxanes being modified with methacrylic esters by reacting --COH-group containing methacrylic esters with organopolysiloxanes containing --SiX groups wherein X is alkoxyl, hydroxyl or chloro and wherein the organopolysiloxanes are reacted from 0.05 to equimolar amounts of pentaerythritol trimethacrylate. The organopolysiloxanes of the present invention exhibit rapid hardening properties under curing conditions. The compounds and compositions obtained with this process are also disclosed.
Claims12
In a process for the preparation of organopolysiloxanes which are modified with methacrylic esters wherein --COH-group containing methacrylic esters are reacted with organopolysiloxanes which contain --SiX groups wherein X is alkoxyl, hydroxyl or chloro, the improvement which comprises said organopolysiloxanes being reacted with from 0.05 to equimolar amounts, based on --COH and --SiX groups, of pentaerythritol trimethacrylate, the organpolysiloxanes having the formula ##EQU2## in which R.sup.1 is an alkyl group with 1 to 4 carbon atoms or an aryl group;
- X is a chloro group or methoxy;
- a has a value from 1.0 to 2.0;
- b has a value from 0.02 to 1.6;
- a+b.ltoreq.2.66;
- and
- the siloxane molecule has from 3 to 100 Si atoms.
Dependencies are inferred from the claim text.