CROSSLINKABLE BINDERS FOR SOLVENT BASED INTUMESCENT COATINGS

• US 20180187037A1
• Filed: 02/28/2018
• Published: 07/05/2018
• Est. Priority Date: 06/02/2016
• Status: Active Grant

• Current Assignee: PPG Coatings Europe B.V (Nouryon BV)
• Original Assignee: PPG Coatings Europe B.V (Nouryon BV)
• Granted Patent: US 10,640,668 B2
• Time in Patent Office: Days
• CPC Class Codes: C08F 212/08 Styrene
• CPC Class Codes: C09D 125/08 Copolymers of styrene C09D129/08, C09D135/06, C09D155/02 take precedence
• CPC Class Codes: C09D 5/00 Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced electrically insulating plastics, resins or waxes H01B3/30; Filling pastes
• CPC Class Codes: C09D 5/185 Intumescent paints

Abstract

Self-crosslinkable binder compositions which include a copolymer obtained by reacting a mixture of monomers in the presence of an organic solvent, wherein the monomer mixture includes a carboxylic acid monomer, a polymerizable ethylenically unsaturated monomer, and a crosslinkable acrylamide monomer. Intumescent coatings containing the self-crosslinkable binder, and substrates coated with the intumescent coatings are also disclosed.

Claims

1. A self-crosslinkable binder composition for an intumescent coating, the binder composition comprising a copolymer obtained by reacting a monomer mixture in the presence of an organic solvent, the monomer mixture comprising:

(i) 0.5 to 10 percent by weight of a polymerizable ethylenically unsaturated carboxylic acid monomer;

(ii) 50 to 90 percent by weight of a polymerizable ethylenically unsaturated monomer different from (i); and

(iii) 7 to 50 percent by weight of a crosslinkable acrylamide monomer,

wherein the percent by weight is based on the total weight of the monomer mixture, and wherein the binder has an acid value of less than 100 mg KOH/g and the copolymer has a weight average molecular weight of greater than 20,000 as determined by gel permeation chromatography relative to polystyrene standards with the unit of g/mol.

2. The binder composition of claim 1, wherein the polymerizable ethylenically unsaturated carboxylic acid monomer (i) comprises (meth)acrylic acid, itaconic acid, maleic acid, fumaric acid, or combinations thereof.

3. The binder composition of claim 1, wherein the polymerizable ethylenically unsaturated monomer (ii) comprises styrene, α

-methyl styrene, t-butylstyrene, vinyl toluene, or a combination thereof.

4. The binder composition of claim 1, wherein the crosslinkable acrylamide monomer (iii) comprises 10 to 30 percent by weight of n-butoxymethyl acrylamide, based on the total weight of the monomer mixture.

5. The binder composition of claim 1, comprising 30% solids by weight or more of the copolymer in the organic solvent, based on the total weight of the binder.

6. The binder composition of claim 1, wherein the copolymer has a weight average molecular weight of greater than 30,000 as determined by gel permeation chromatography relative to polystyrene standards with the unit of g/mol.

7. The binder composition of claim 1, wherein the binder has an acid value of less than 20 mg KOH/g.

8. The binder composition of claim 1, wherein the monomer mixture is reacted in the presence of a chain transfer agent and a free radical initiator.

9. The binder composition of claim 1, wherein the copolymer has an alpha parameter derived from the Mark-Houwink equation of between 0.4 and 0.50.

21. An intumescent coating composition comprising the binder composition of claim 1.

22. A substrate coated at least in part with the intumescent coating composition of claim 21.

10-18. -18. (canceled)

19. An intumescent coating composition comprising:

(a) a self-crosslinkable binder composition comprising a copolymer having an alpha parameter derived from the Mark-Houwink equation of between 0.4 and 0.50, the copolymer obtained by reacting a monomer mixture comprising (i) 0.5 to 10 percent by weight of a polymerizable ethylenically unsaturated carboxylic acid monomer, (ii) 50 to 90 percent by weight of a polymerizable ethylenically unsaturated monomer different than (i), and (iii) 7 to 50 percent by weight of a crosslinkable acrylamide monomer, in the presence of an organic solvent, wherein the percent by weight is based on the total weight of the monomer mixture;

(b) an acid source;

(c) a carbon source; and

(d) a gas source,

wherein the coating composition, following application to a substrate, achieves a shore A hardness of greater than 90 as measured according to ASTM D2240 after 150 hours of drying time at ambient conditions or 25 hours of drying time at 40°

C.

20. A substrate coated at least in part with the intumescent coating composition of claim 19.

23. A self-crosslinkable binder composition comprising a copolymer obtained by reacting a monomer mixture in the presence of an organic solvent, the monomer mixture comprising:

(i) 0.5 to 10 percent by weight of a polymerizable ethylenically unsaturated carboxylic acid monomer;

(ii) 50 to 90 percent by weight of a polymerizable ethylenically unsaturated monomer different from (i); and

(iii) 7 to 50 percent by weight of a crosslinkable acrylamide monomer,

wherein the percent by weight is based on the total weight of the monomer mixture, and wherein the binder has an acid value of less than 100 mg KOH/g and the copolymer has a weight average molecular weight of greater than 20,000 as determined by gel permeation chromatography relative to polystyrene standards with the unit of g/mol.