Silicone release composition

Claim 2

A release modifier for silicone release compositions comprising a MQ resin consisting essentially of units of the formulae SiO.sub.2 (Q) and R.sub.3 SiO.sub.1/2 (M) wherein R is selected from the group consisting of monovalent hydrocarbon groups having up to 3 carbon atoms, a hydrogen atom, an alkenyl group of the formula --R'CH═CH 2 and an oxyalkenyl group of the formula --OR'CH═CH 2 , wherein R' denotes an alkylene group of from 4 to 12 carbon atoms, provided there is at least one group selected from the group consisting of --R'CH═CH 2 and --OR'CH═CH 2 present per MQ molecule and that no more than 50% of all M units comprise a substituent selected from the group consisting of --R'CH═CH 2 and --OR'CH═CH 2 groups.

Claim 3

A release modifier according to claim 1 wherein the MQ resins consist essentially of monovalent (M) and tetravalent (Q) siloxane units in ratio of from 1.1/1 to 1.8/1.

Claim 4

A release modifier according to claim 1 wherein all R units are selected from the group consisting of methyl groups and groups of the formula --R'CH═CH 2 , wherein R' denotes an alkylene group of 6 to 10 carbon atoms.

Claim 5

A release modifier according to claim 1 wherein the weight percentage of the --R'CH═CH 2 or --OR'CH═CH 2 groups in the MQ resin is no more than 25% of the total weight of the MQ resin.

Claim 6

A release modifier according to claim 1 wherein the ratio of units wherein one of the R groups is selected from the group consisting of a group of the formula --R'--CH═CH 2 and a group of the formula --OR'--CH═CH 2 over tetravalent units of the formula SiO 2 is from 0.05/1 to 0.5/1.

Claim 7

A release modifier according to claim 1 which comprises from 90 to 100% by weight of the MQ resins.

Claim 8

A solventless release composition comprising (A) a release modifier which comprises a MQ resin consisting essentially of units of the formulae SiO 2 and R 3 SiO 1/2 wherein R is selected from the group consisting of a monovalent hydrocarbon group having up to 3 carbon atoms, a hydrogen atom, an alkenyl group of the formula --R'CH═CH 2 and an oxyalkenyl group of the formula --OR'CH═CH 2 , wherein R' denotes an alkylene group of from 4 to 12 carbon atoms, provided there is at least one group --R'CH═CH 2 present per MQ molecule and that no more than 50% of all M units comprise a substituent selected from the group consisting of --R'CH═CH 2 and --OR'CH═CH 2 groups, (B) an organosilicon compound having at least three silicon-bonded hydrogen atoms per molecule, (C) an effective amount of a precious metal catalyst capable of promoting the addition reaction between alkenyl or oxyalkenyl groups and silicon-bonded hydrogen groups and (D) optionally a diorganopolysiloxane having at least 2 alkenyl-functional silicon-bonded substituents.

Claim 9

A solventless release composition comprising (A) a release modifier which comprises a MQ resin consisting essentially of units of the formulae SiO 2 and R 3 SiO 1/2 wherein R is selected from the group consisting of a monovalent hydrocarbon group having up to 3 carbon atoms, a hydrogen atom, an alkenyl group of the formula --R'CH═CH 2 and an oxyalkenyl group of the formula --OR'CH═CH 2 , wherein R' denotes an alkylene group of from 4 to 12 carbon atoms, provided there is at least one group --R'CH═CH 2 present per MQ molecule and that no more than 50% of all M units comprise a substituent selected from the group consisting of --R'CH═CH 2 and --OR'CH═CH 2 groups, (B) an organosilicon compound having at least three silicon-bonded hydrogen atoms per molecule, (C) an effective amount of a precious metal catalyst capable of promoting the addition reaction between alkenyl or oxyalkenyl groups and silicon-bonded hydrogen groups and (D) optionally a diorganopolysiloxane having at least 2 alkenyl-functional silicon-bonded substituents.

Claim 10

A solventless release composition according to claim 7 wherein Component (B) is selected from the group consisting of organosilicon compounds having the general formula R 2 2 R 3 SiO--[R 2 2 SiO] m --[R 2 HSiO] n --SiR 2 2 R 3 and organosilicon compounds having the general formula ##STR2## wherein R 2 is selected from the group consisting of alkyl and aryl groups having up to 8 carbon atoms, R 3 is selected from the group consisting of a group R 2 and a hydrogen atom, m has a value of from 0 to 20, n has a value of from 1 to 70, and there are at least 3 silicon-bonded hydrogen atoms present.

Claim 11

A solventless release composition according to claim 7 wherein the number ratio of SiH/Si-alkenyl or Si-oxyalkenyl is from 1.1/1 to 1.8/1.

Claim 12

A solventless release composition according to claim 7 Component (D) is present and is a polydiorganosiloxane having the general formula X 2 Y°SiO--[X 2 SiO] x --[XYSiO] y --SiX 2 Y°, wherein each X is selected from a group consisting of a phenyl radical and a saturated hydrocarbon group having 1 to 6 carbon atoms, at least 90% of all X groups being methyl groups, Y denotes an alkenyl group having up to 6 carbon atoms, Y° is selected from a group consisting of a group Y and a group X and the average value of the sum total of x and y is such that the resulting viscosity of the polydiorganosiloxane is at least 10 mPa.s at 25° C.

Claim 13

A solventless release coating according to claim 10 wherein each alkenyl group Y in component (D) is a vinyl or hexenyl group.

Claim 14

A solventless release composition according to claim 7 wherein the weight percentage of component (A) based on the total weight of components (A), (C) and (D) combined is from 10 to 80%.

Claim 15

A solventless release composition according to claim 7 which also comprises one or more ingredients selected from the group consisting of MQ resins having vinyl substituents on some of the monofunctional units, α-olefins, cure inhibitors and bath life extenders.

Claim 16

A solventless release composition according to claim 7 which is stored by keeping components (A) and (C) separate from component (B).

Claim 17

A process of coating a substrate comprising applying to the substrate a solventless release composition according to claim 7 and thereafter causing the composition to cure.

Claim 18

A process according to claim 15 wherein the substrate is flexible and the composition is applied to the substrate in a layer of 0.1 to 2.0 grams per square meter of surface.

Claim 19

A process according to claim 15 wherein the curing is effected by heating the coated substrate to a temperature below 200° C.