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US 5,332,797 AGranted
Silicone release compositions
AssigneeMinnesota Mining and Manufacturing Company
InventorsCarl R. Kessel, Maureen C. Nelson
Life of this patent
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Abstract
A composite structure comprising a substrate bearing a layer of release coating prepared from one or more epoxypolysiloxanes together providing cycloaliphatic epoxy group(s) and non-cycloaliphatic (i.e., linear or branched aliphatic) epoxy group(s). The resulting release coating cures quickly and exhibits low release levels to adhesives. An oligomeric epoxypolysiloxane comprising both cycloaliphatic and non-cycloaliphatic epoxy groups is also disclosed.
Claims1
An oligomeric epoxypolysiloxane of the formula ##STR19## wherein R is a lower alkyl group having one to three carbon atoms,
- R.sup.l is a monovalent hydrocarbon group of 4 to 20 carbon atoms,
- E is a monovalent linear or branched aliphatic epoxy group;
- G is a monovalent cycloaliphatic epoxy group;
- M is a silyl group selected from the group consisting of R.sub.3 Si--, R.sub.2 R.sup.1 Si--, RR.sup.1.sub.2 Si--, R.sup.1.sub.3 Si--, R.sub.2 ESi--, RE.sub.2 Si--, E.sub.3 Si--, R.sup.1.sub.2 ESi--, R.sup.1 E.sub.2 Si--, RR.sup.1 ESi--, R.sub.2 GSi, RG.sub.2 Si--, G.sub.3 Si--, R.sup.1.sub.2 GSi--, R.sup.1 G.sub.2 Si--, RR.sup.1 GSi--, REGSi--, E.sub.2 GSi--, G.sub.2 ESi--, and R.sup.1 EGSi--, in which R, R.sup.1, E and G are defined above;
- y is zero or a number having a value of up to about 200;
- w is zero or a number having a value of up to about 200-y;
- x is zero or a number having a value of up to about 185;
- z is zero or a number having a value of up to about 135;
- and
- q is a number having a value of 1 to about 75;
- with the proviso that said epoxypolysiloxane comprises at least one G group and one E group, the ratio of G to E groups is from about 1:10 to 2:1, and the total number of E and G groups is about 5 to 50% of the total number of siloxane units.
8 more elements
Dependencies are inferred from the claim text.