Silicone release coating composition and low release force emulsion silicone release coating for films and papers having cured release coating

Patent metadata

Field	Value
Publication number	US-10155883-B2
Application number	US-201415321299-A
Country	US
Kind code	B2
Filing date	Jun 27, 2014
Priority date	Jun 27, 2014
Publication date	Dec 18, 2018
Grant date	Dec 18, 2018

Abstract

A silicone release coating composition comprises:
(A) 100 weight parts of an organopolysiloxane fluid having a viscosity at 25° C. of 50 to 10,000 mPa·s and an alkenyl content of 0.10 to 3.0 wt %; (B) 0.5-40 weight parts of a diorganopolysiloxane represented by the average structural formula (1):

R c 3 SiO(R b R c SiO 2/2 ) n1 (R c 2 SiO 2/2 ) n2 SiR c 3   (1)
 wherein R b is an alkenyl group; R c is an alkyl group or a phenyl group; n1 provides an alkenyl content of 0.05 to 0.80 wt. %; n2 is at least 1; and n1+n2 provides this component with a viscosity at 25° C. of 5,000 to 150,000 mPa·s; (C) an organohydrogenpolysiloxane that has a viscosity at 25° C. of 1 to 1,000 mPa·s, at least two silicon-bonded hydrogen atoms in each molecule, and an alkyl group or a phenyl group for its silicon-bonded organic groups; (D) a hydrosilylation reaction catalyst in a catalytic amount; (E) a surfactant; (F) water; and (G) an inhibitor.

First claim

The invention claimed is:

1. A silicone release coating composition comprising:
(A) 100 weight parts of an organopolysiloxane fluid having a viscosity at 25° C. of 50 to 10,000 mPa·s and an alkenyl content of 0.10 to 3.0 wt %;
(B) 0.5-40 weight parts of a diorganopolysiloxane represented by the average structural formula (1):
R c 3 SiO(R b R c SiO 2/2 ) n1 (R c 2 SiO 2/2 ) n2 SiR c 3   (1)

 wherein R b is alkenyl group having 2 to 8 carbon atoms; R c is alkyl group having 1 to 8 carbon atoms or a phenyl group; n1 provides an alkenyl content of 0.05 to 0.80 wt %; n2 is at least 1; and n1+n2 provides this component with a viscosity at 25° C. of 20,000 to 150,000 mPa·s;
(C) an organohydrogenpolysiloxane that has a viscosity at 25° C. of 1 to 1,000 mPa·s, at least two silicon-bonded hydrogen atoms in each molecule, and an alkyl group having 1 to 8 carbon atoms or a phenyl group for its silicon-bonded organic groups, in an amount sufficient to provide a value of 0.8:1 to 5:1 for the molar ratio of silicon-bonded hydrogen atoms in this component to the alkenyl groups in components (A) and (B);
(D) a hydrosilylation reaction catalyst in a catalytic amount;
(E) a surfactant;
(F) water; and
(G) an inhibitor.

2. The silicone release coating composition according to claim 1 , wherein the alkenyl content of component (B) is within a range of 0.05 to 0.50 wt %.

3. The silicone release coating composition according to claim 1 , wherein component (A) is 100 weight parts of at least one organopolysiloxane fluid selected from the group consisting of: a linear organopolysiloxane, a branched organopolysiloxane, a mixture of organopolysiloxanes having different alkenyl contents of 0.10 to 3.0 wt %, and a mixture of a linear organopolysiloxane and a branched organopolysiloxane.

4. The silicone release coating composition according to claim 1 , wherein component (A) is a mixture of (A-1) a polydimethylsiloxane having alkenyl groups only in its molecular terminals and (A-2) a polydimethylsiloxane having alkenyl groups in its molecular terminals and its side-chain positions.

5. The silicone release coating composition according to claim 1 , wherein component (A) comprises at least one organopolysiloxane fluid having a branched structure and a viscosity at 25° C. of 50 to 10,000 mPa·s, comprising the siloxane units (i) to (iii) described below, and having a straight-chain moiety comprising a plurality of siloxane unit (ii), and a branch point comprising siloxane unit (i), wherein the terminals of the straight-chain moiety are end blocked by the siloxane unit (iii);
(i) the siloxane unit represented by the general formula SiO 4/2 : 1 or more;
(ii) the siloxane unit represented by the general formula R 2 SiO 2/2 : 15 to 995;
(iii) the siloxane unit represented by the general formula R a R 2 SiO 1/2 ;

in the formulae, R a is selected from the group consisting of alkyl groups having 1 to 8 carbon atoms, alkenyl groups having 2 to 8 carbon atoms, a phenyl group, alkoxy groups having 1 to 8 carbon atoms, and a hydroxyl group, and R is selected from the group consisting of alkyl groups having 1 to 8 carbon atoms, alkenyl groups having 2 to 8 carbon atoms, and a phenyl group, wherein at least 0.10 to 3.0 wt % of the R a and R in the molecule are alkenyl groups having 2 to 8 carbon atoms and at least 50% of the total number of R a and R in the molecule are alkyl groups having 1 to 8 carbon atoms.

6. The silicone release coating composition according to claim 5 , wherein component (A) comprises at least one organopolysiloxane fluid having a branched structure and represented by the average siloxane unit formula (2):
(R a R 2 SiO 1/2 ) 4 (R 2 SiO 2/2 ) m (SiO 4/2 )  (2)

wherein R a is selected from the group consisting of alkyl groups having 1 to 8 carbon atoms, alkenyl groups having 2 to 8 carbon atoms, a phenyl group, alkoxy groups having 1 to 8 carbon atoms, and a hydroxyl group; R is selected from the group consisting of alkyl groups having 1 to 8 carbon atoms, alkenyl groups having 2 to 8 carbon atoms, and a phenyl group; at least 3 wt % of the R a and R in the molecule are alkenyl groups having 2 to 8 carbon atoms; at least 50% of the total number of R a and R in the molecule are alkyl groups having 1 to 8 carbon atoms; and m=15 to 995.

7. The silicone release coating composition according to claim 5 , wherein component (A) is an organopolysiloxane having a branched structure and represented by the average siloxane unit formula (3):
[(R b R c 2 SiO 1/2 ) n (R d R c 2 SiO 1/2 ) 1-n ] 4 (R b R c SiO 2/2 ) m1 (R c 2 SiO 2/2 ) m2 (SiO 4/2 )  (3)

wherein R b is an alkenyl group having 2 to 8 carbon atoms; R c is an alkyl group having 1 to 8 carbon atoms or a phenyl group; R d is selected from the group consisting of alkyl groups having 1 to 8 carbon atoms, alkoxy groups having 1 to 8 carbon atoms, and a hydroxyl group; there are at least three R b in the molecule; at least 50% of the total number of R b , R c , and R d in the molecule are alkyl groups having 1 to 8 carbon atoms; n is 0 or 1; m1 is at least 1; m2 is at least 0; and m1+m2=15 to 995.

8. The silicone release coating composition according to claim 1 , wherein component (E) 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 polyvinylacetates.

9. The silicone release coating composition according to claim 1 , wherein component (G) is a hydrosilylation reaction inhibitor, is noncuring at ambient temperature, and cures under the application of heat.

10. A low release force emulsion silicone release coating for films and papers yielded by curing the silicone release coating composition according to claim 1 .

11. A production method of a low release force emulsion silicone release coating for films and papers, said method comprising:
applying the silicone release coating composition according to claim 1 on at least one side of a film or a paper; and
curing the applied coating at a temperature of at least 100° C.

12. The silicone release coating composition according to claim 1 , wherein component (E) comprises an ethoxylated alcohol or a polyoxyethylene alkyl ether.

13. The silicone release coating composition according to claim 12 , wherein component (E) further comprises a polyvinyl alcohol.

14. The silicone release coating composition according to claim 1 , wherein component (E) is present in an amount of from 0.5 to 30 weight parts per 100 weight parts of component (A).

15. The silicone release coating composition according to claim 1 , wherein component (F) is present in an amount of from 60 to 2000 weight parts per 100 weight parts of component (A).

16. The silicone release coating composition according to claim 1 , wherein component (G) is present in an amount of from 0.05 to 2 weight parts per 100 weight parts of component (A).

17. The silicone release coating composition according to claim 1 , wherein component (B) has a viscosity at 25° C. of 20,000 to 130,000 mPa·s.

Assignees

• Dow Corning
• Dow Corning China Holding Co Ltd
• Dow Silicones Corp
• Dow Shanghai Holding Co Ltd

Inventors

• Huang Fuming
• Kuo Chung Mien
• Wang Yang

Classifications

• C09D5/022

  Emulsions, e.g. oil in water · CPC title

• C08K5/56

  Organo-metallic compounds, i.e. organic compounds containing a metal-to-carbon bond · CPC title

• C08G77/20

  containing silicon bound to unsaturated aliphatic groups · CPC title

• C09D183/04 Primary

  Polysiloxanes · CPC title

• C08G77/80

  Siloxanes having aromatic substituents, e.g. phenyl side groups · CPC title