COATING COMPOSITIONS CAPABLE OF PRODUCING SURFACES WITH DRY-ERASE PROPERTIES

• US 20160060477A1
• Filed: 08/26/2014
• Published: 03/03/2016
• Est. Priority Date: 08/26/2014
• Status: Active Grant

• Current Assignee: Sumika Bayer Urethane Co., Ltd (Covertro Deutschland AG), Covestro LLC (Covestro AG)
• Original Assignee: Sumika Bayer Urethane Co., Ltd (Covertro Deutschland AG), Bayer Materialscience LLC (Covestro AG)
• Inventors: Kendi, Margaret A., Nakao, Makoto, Owens, Steven
• Granted Patent: US 9,376,585 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B43K 8/024 with writing-points comprising felt
• CPC Class Codes: C08F 212/08 Styrene
• CPC Class Codes: C08F 220/06 Acrylic acid; Methacrylic acid; Metal salts or ammonium salts thereof
• CPC Class Codes: C08F 220/08 Anhydrides
• CPC Class Codes: C08F 220/1804 C4-(meth)acrylate, e.g. butyl (meth)acrylate, isobutyl (meth)acrylate or tert-butyl (meth)acrylate
• CPC Class Codes: C08F 220/1808 C8-(meth)acrylate, e.g. isooctyl (meth)acrylate or 2-ethylhexyl (meth)acrylate
• CPC Class Codes: C08F 220/20 of polyhydric alcohols or phenols , e.g. 2-hydroxyethyl (meth)acrylate or glycerol mono-(meth)acrylate
• CPC Class Codes: C08K 5/34 Heterocyclic compounds having nitrogen in the ring
• CPC Class Codes: C09D 125/04 Homopolymers or copolymers of styrene
• CPC Class Codes: C09D 125/14 with unsaturated esters
• CPC Class Codes: C09D 133/02 Homopolymers or copolymers of acids; Metal or ammonium salts thereof

Abstract

Disclosed are waterborne coating compositions that include: (a) a base-neutralized carboxylic acid functional polyacrylate; and (b) a water-miscible polyaziridine, in which the composition is substantially free of isocyanate functionality. Also disclosed are methods of using such compositions to produce a dry-erase surface and kits that include such compositions.

Claims

1. A waterborne coating composition comprising:

(a) a base-neutralized carboxylic acid functional polyacrylate having a calculated Tg of greater than 50°

C. and that is a reaction product of reactants comprising;

(a1) at least 50% by weight of a hardening vinyl aromatic monomer, based on the total weight of the reactants;

(a2) a plasticizing ethylenically unsaturated monomer that does not include carboxylic acid or hydroxyl groups; and

(a3) a carboxylic-acid functional ethylenically unsaturated monomer; and

(b) a water-miscible polyaziridine,

wherein the coating composition is substantially free of isocyanate functionality.

2. The coating composition of claim 1, wherein the calculated Tg is at least 60°

C.

3. The coating composition of claim 2, wherein the calculated Tg is at least 65°

C.

4. The coating composition of claim 3, wherein the calculated Tg of at least 70°

C.

5. The coating composition of claim 1, wherein the composition has a viscosity at 23°

C. of less than 1000 cPs.

6. The coating composition of claim 1, wherein the reactants further comprise:

(a4) a hydroxyl functional ethylenically unsaturated monomer.

7. The coating composition of claim 1, wherein (a1) comprises styrene in an amount of at least 80% by weight, based on the total weight of reactant (a1).

8. The coating composition of claim 1, wherein the sum of monomers (a1) and (a3) comprises at least 70% by weight, based on the total weight of reactants used to make the polyacrylate.

9. The coating composition of claim 1, wherein the reactants comprise:

(a1) 50 to 85% by weight styrene;

(a2) 5 to 30% by weight of n-butyl acrylate, ethyl acrylate and/or 2-ethylhexyl acrylate;

(a3) 1 to 5% by weight of acrylic acid and/or methacrylic acid;

(a4) optionally 2 to 30% by weight of hydroxypropyl methacrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate and/or hydroxyethyl acrylate,

wherein the sum of the % by weights of (a1) to (a4) is 100.

10. The coating composition of claim 1, comprising:

(i) at least 70% by weight of the base-neutralized carboxylic acid functional polyacrylate; and

(ii) at least 2% by weight of the water-miscible polyaziridine,

wherein the weight percents are based on the total weight of resin solids in the coating composition.

11. The coating composition of claim 1, wherein the composition comprises no more than 0.2 equivalents of free isocyanate groups per equivalents of any isocyanate-reactive groups.

12. A method of using the coating composition of claim 1, comprising:

(A) applying the composition to a substrate; and

(B) allowing the composition to cure at ambient temperature to form a cured coating, wherein the substrate comprises a wall, a chalkboard or a blackboard and/or a material comprising a cellulosic material, fiber board, particle board, and/or gypsum board.

13. A kit comprising:

(a) the coating composition of claim 1; and

(b) a marker pen.

14. A method of using the coating composition of claim 1, comprising:

(A) applying the composition to a substrate; and

(B) allowing the composition to cure at ambient temperature to form a cured coating, wherein the substrate is a frame of an architectural article.