Solventless release coating organopolysiloxane composition and sheet-form substrate having cured release coating

Patent metadata

Field	Value
Publication number	US-10030169-B2
Application number	US-201415031335-A
Country	US
Kind code	B2
Filing date	Oct 24, 2014
Priority date	Oct 25, 2013
Publication date	Jul 24, 2018
Grant date	Jul 24, 2018

Abstract

This invention relates to solventless release coating organopolysiloxane composition and sheet-form substrate having cured release coating, providing a solventless release coating organopolysiloxane composition having a viscosity of 50 to 3,000 mPa s, comprising (A) 100 parts of an organopolysiloxane fluid having a viscosity at 25° C. of 10 to 1,000 mPa s and alkenyl content of 0.10 to 3.0 wt %; (B) 0.5 to 15 parts of a diorganopolysiloxane having a viscosity at 25° C. of 10,000 to 150,000 mPa s, and 0.05 to 0.30% of alkenyl groups at the pendant position of its siloxane-chain and trialkylsiloxy-terminals; (C) a prescribed quantity of an organohydrogenpolysiloxane; and (D) a hydrosilylation reaction catalyst. Also, a cured release coating-bearing sheet-form substrate that has a cured coating from this solventless release coating organopolysiloxane composition is provided.

First claim

The invention claimed is:

1. A solventless release coating organopolysiloxane composition having a viscosity of 50 to 3,000 mPa·s, the composition comprising:
(A) 100 parts by weight of an organopolysiloxane fluid having a viscosity at 25° C. of 10 to 1,000 mPa·s and an alkenyl content of 0.10 to 3.0 wt %;
(B) 0.5 to 15 parts by weight 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 having 2 to 8 carbon atoms; R c is an alkyl group having 1 to 8 carbon atoms or a phenyl group; n1 is a number that provides an alkenyl group content of 0.05 to 0.30 wt %; n2 is a number with a value of at least 1; and n1+n2 is a number that provides a viscosity at 25° C. of 10,000 to 150,000 mPa·s;

(C) an organohydrogenpolysiloxane having a viscosity at 25° C. of 1 to 1,000 mPa·s and at least two silicon-bonded hydrogen atoms in each molecule, wherein each silicon-bonded organic group is an alkyl group having 1 to 8 carbon atoms or a phenyl group, and wherein component (C) is present in an amount sufficient to provide a value of 0.8:1 to 5:1 for the molar ratio of the silicon-bonded hydrogen atoms in component (C) to the alkenyl groups in components (A) and (B); and
(D) a hydrosilylation reaction catalyst in a catalytic quantity;
wherein component (A) comprises 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.

2. The solventless release coating organopolysiloxane composition according to claim 1 , wherein the alkenyl group content of component (B) is 0.05 to 0.20 wt %.

3. The solventless release coating organopolysiloxane composition according to claim 1 , wherein component (A) comprises an organopolysiloxane fluid selected from the group consisting of: a linear organopolysiloxane, a branched organopolysiloxane, a mixture of organopolysiloxanes having different alkenyl group contents of 0.10 to 3.0 wt %, and a mixture of a linear organopolysiloxane and a branched organopolysiloxane.

4. The solventless release coating organopolysiloxane composition according to claim 1 , wherein component (A) comprises at least one organopolysiloxane fluid having a branched structure and comprising the siloxane units (i) to (iii) described below, and having a straight-chain moiety comprising a plurality of siloxane unit (ii), and having 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 an alkyl group having 1 to 8 carbon atoms, an alkenyl group having 2 to 8 carbon atoms, a phenyl group, an alkoxy group having 1 to 8 carbon atoms, and a hydroxyl group, and R is selected from the group consisting of an alkyl group having 1 to 8 carbon atoms, an alkenyl group 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 is alkyl groups having 1 to 8 carbon atoms.

5. The solventless release coating organopolysiloxane composition according to claim 4 , wherein component (A) comprises an organopolysiloxane fluid 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 an alkyl group having 1 to 8 carbon atoms, an alkenyl group having 2 to 8 carbon atoms, a phenyl group, an alkoxy group having 1 to 8 carbon atoms, and a hydroxyl group;
R is selected from the group consisting of an alkyl group having 1 to 8 carbon atoms, an alkenyl group 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 is an alkyl group having 1 to 8 carbon atoms; and
m=15 to 995.

6. The solventless release coating organopolysiloxane composition according to claim 4 , wherein component (A) comprises an organopolysiloxane fluid 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 an alkyl group having 1 to 8 carbon atoms, an alkoxy group 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 is an alkyl group having 1 to 8 carbon atoms;
n is 0 or 1; m1 is a number with a value of at least 1; m2 is a number with a value of at least 0; and m1+m2=15 to 995.

7. The solventless release coating organopolysiloxane composition according to claim 1 , further comprising:
(E) 0.001 to 5 parts by weight of a hydrosilylation reaction inhibitor that is non-curing at ambient temperature and cures under the application of heat.

8. A cured release coating-bearing sheet-form substrate yielded by curing the solventless release coating organopolysiloxane composition according to claim 1 in the form of a thin film on a sheet-form substrate.

9. The cured release coating-bearing sheet-form substrate according to claim 8 , wherein the sheet-form substrate is glassine paper, clay-coated paper, polyolefin-laminated paper, thermoplastic resin film, or metal foil.

10. A production method for a cured release coating-bearing sheet-form substrate, the method comprising:
applying a solventless release coating organopolysiloxane composition on at least one side of a sheet-form substrate with a multiple rolls coater;
wherein the solventless release coating organopolysiloxane composition is according to claim 1 .

11. The production method for a cured release coating-bearing sheet-form substrate according to claim 10 , wherein the sheet-form substrate is glassine paper, clay-coated paper, polyolefin-laminated paper, thermoplastic resin film, or metal foil.

Assignees

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

Inventors

• Kuo Chung Mien
• Wang Yang Wayne
• Zhou Johnny Yan

Classifications

• C09J7/40

  characterised by release liners · CPC title

• C09J7/22

  Plastics; Metallised plastics · CPC title

• C09J7/21

  Paper; Textile fabrics · CPC title

• C09J7/201

  characterised by the release coating composition on the carrier layer · CPC title

• C09J7/401

  characterised by the release coating composition · CPC title