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-2017145256-A1
Application number	US-201415321299-A
Country	US
Kind code	A1
Filing date	Jun 27, 2014
Priority date	Jun 27, 2014
Publication date	May 25, 2017
Grant date	—

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

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 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 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 organohydrogenpolysiloxane 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 organopolysliloxane, a branched organopolysiloxane, a mixture of organopolysiloxanes having different alkenyl contents of 0.10 to 3.0 wt %, and a mixture of a linear organopolysliloxane 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 c 2 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).

Assignees

• Dow Corning
• Dow Corning (China) Holding Co Ltd

Inventors

• Huang Fuming
• Kuo Chung Mien
• Wang Yang

Classifications

• C09D183/04 Primary

  Polysiloxanes · CPC title

• D21H19/12

  applied as a solution using water as the only solvent, e.g. in the presence of acid or alkaline compounds · CPC title

• C09D5/022

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

• C08G77/12

  containing silicon bound to hydrogen · CPC title

• C08G77/20

  containing silicon bound to unsaturated aliphatic groups · CPC title