Anchorage additive emulsion for silicone release coating composition
View Patent ↗A silicone emulsion comprises: (A) a silicone compound comprising an anchorage additive for enhancing the adhesion to a polymer film substrate; (B) at least one surfactant; and (C) water. The anchorage additive is the reaction product of (A1) a fluid polyorganosiloxane containing at least one alkenyl group and at least one silanol group with (A2) a hydrolysable silane containing at least one epoxide group. A water-based anchorage additive comprises the silicone emulsion. A silicone release coating composition comprises: (X1) the silicone emulsion; and (X2) at least one curable silicone composition, e.g. a water-based silicone release coating composition. The curable silicone release coating composition may be applied to a sheet-form substrate and cured to form a release-coated layer having good release property and improved rub-off resistance on the substrate.
1. A silicone release coating composition comprising:
(X1) a silicone emulsion comprising:
(A) 0.1 to less than 80.0 parts by weight of a silicone compound comprising an anchorage additive for enhancing the adhesion to a polymer film substrate, wherein the anchorage additive is the reaction product of (A1) a fluid polyorganosiloxane containing at least one alkenyl group and at least one silanol group with (A2) a hydrolysable silane containing at least one epoxide group;
(B) 0.1 to less than 20.0 parts by weight of at least one surfactant, wherein component (B) comprises at least one nonionic surfactant selected from the group consisting of polyether compounds, polyether-modified silicones, water-soluble polyester compounds, water-soluble polyvinyl alcohols, and water-soluble polyvinylacetate; and
(C) 5.0 to 99.8 parts by weight of water; and
(X2) at least one curable silicone composition.
2. The silicone release coating composition according to claim 1 , wherein the fluid polyorganosiloxane (A1) is a copolymer of methylvinylsiloxane units and dimethylsiloxane units, and has a degree of polymerisation of at least 4 and up to 50 siloxane units with terminal silanol groups.
3. The silicone release coating composition according to claim 2 , wherein component (A1) has a degree of polymerisation of at least 6 and up to 30 siloxane units.
4. The silicone release coating composition according to claim 1 , wherein the hydrolysable silane (A2) is an (epoxy-substituted alkyl) di- or tri-alkoxy silane.
5. The silicone release coating composition according to claim 1 , wherein the silicone compound is a mixture of the anchorage additive and (A3) at least one silicone selected from the group consisting of a polyorganosiloxane having at least one alkenyl group, a polyorganosiloxane having at least one alkoxy group, a polyorganosiloxane having at least one epoxy group, a polyorganosiloxane having at least one Si-bonded hydrogen atom, and silicone resins in the ratio of 100:0 to 20:80 by weight.
6. The silicone release coating composition according to claim 1 , wherein component (B) comprises at least two nonionic surfactants selected from the group consisting of polyether compounds, polyether-modified silicones, water-soluble polyester compounds, water-soluble polyvinyl alcohols, and water-soluble polyvinylacetate.
7. The silicone release coating composition according to claim 1 , wherein the droplets of the silicone emulsion (X1) have an average particle size of less than 1 μm, as measured by a laser diffraction/dispersion method for emulsion particles.
8. The silicone release coating composition according to claim 1 wherein component (X2) is a water-based hydrosilylation reaction curable silicone composition.
9. A cured release coating-bearing sheet-form substrate yielded by curing the silicone release coating composition according to claim 1 in the form of a thin film on a sheet-form substrate.
10. The cured release coating-bearing sheet-form substrate according to claim 9 , wherein the sheet-form substrate is glassine paper, clay-coated paper, polyolefin-laminated paper, thermoplastic resin film, or metal foil.
11. A method of producing a cured release coating-bearing sheet-form substrate, said method comprising the steps of:
applying a silicone release coating composition on at least one side of a sheet-form substrate to form a film; and
curing the film at a temperature of at least 100° C.;
wherein the silicone release coating composition is as set forth in claim 1 .
12. The method according to claim 11 , wherein component (X2) of the silicone release coating composition is a water-based hydrosilylation reaction curable silicone composition.
13. The method according to claim 11 , wherein the sheet-form substrate is glassine paper, clay-coated paper, polyolefin-laminated paper, thermoplastic resin film, or metal foil.
14. A silicone release coating composition comprising:
(X1) a silicone emulsion comprising:
(A) 0.1 to less than 80.0 parts by weight of a silicone compound comprising an anchorage additive for enhancing the adhesion to a polymer film substrate, wherein the anchorage additive is the reaction product of (A1) a fluid polyorganosiloxane containing at least one alkenyl group and at least one silanol group with (A2) a hydrolysable silane containing at least one epoxide group;
(B) 0.1 to less than 20.0 parts by weight of at least one surfactant; and
(C) 5.0 to 99.8 parts by weight of water; and
(X2) at least one curable silicone composition;
wherein the droplets of the silicone emulsion (X1) have an average particle size of less than 1 μm, as measured by a laser diffraction/dispersion method for emulsion particles.
15. The silicone release coating composition according to claim 14 , wherein the fluid polyorganosiloxane (A1) is a copolymer of methylvinylsiloxane units and dimethylsiloxane units, and has a degree of polymerisation of at least 4 and up to 50 siloxane units with terminal silanol groups.
16. The silicone release coating composition according to claim 14 , wherein the hydrolysable silane (A2) is an (epoxy-substituted alkyl) di- or tri-alkoxy silane.
17. The silicone release coating composition according to claim 14 , wherein the silicone compound is a mixture of the anchorage additive and (A3) at least one silicone selected from the group consisting of a polyorganosiloxane having at least one alkenyl group, a polyorganosiloxane having at least one alkoxy group, a polyorganosiloxane having at least one epoxy group, a polyorganosiloxane having at least one Si-bonded hydrogen atom, and silicone resins in the ratio of 100:0 to 20:80 by weight.
18. The silicone release coating composition according to claim 14 , wherein component (X2) is a water-based hydrosilylation reaction curable silicone composition.
19. A cured release coating-bearing sheet-form substrate yielded by curing the silicone release coating composition according to claim 14 in the form of a thin film on a sheet-form substrate, optionally wherein the sheet-form substrate is glassine paper, clay-coated paper, polyolefin-laminated paper, thermoplastic resin film, or metal foil.
20. A method of producing a cured release coating-bearing sheet-form substrate, said method comprising the steps of:
applying a silicone release coating composition on at least one side of a sheet-form substrate to form a film; and
curing the film at a temperature of at least 100° C.;
wherein the silicone release coating composition is as set forth in claim 14 .