BISPHENOL A AND AROMATIC GLYCIDYL ETHER-FREE COATINGS

• US 20070036903A1
• Filed: 08/09/2006
• Published: 02/15/2007
• Est. Priority Date: 08/11/2005
• Status: Active Grant

• Current Assignee: Swimc, LLC (The Sherwin-Williams Company)
• Original Assignee: Valspar Sourcing, Inc. (Sherwin-Williams Company)
• Inventors: Robinson, James, Violleau, Anthony, Paulson, Gregory, Mayr, Peter, Cooke, Paul, Fielding, Trevor, Goodwin, Ronald
• Granted Patent: US 8,142,858 B2
• Time in Patent Office: Days
• US Class Current: 427/402
• CPC Class Codes: B05D 7/14 to metal, e.g. car bodies involving a chemical reaction between the metal and the coating C23
• CPC Class Codes: B05D 7/53 Base coat plus clear coat type
• CPC Class Codes: B05D 7/542 the two layers being cured or baked together
• CPC Class Codes: B05D 7/5483 No curing step for any layer
• CPC Class Codes: B65D 25/14 Linings or internal coatings of containers made by folding or erecting blanks made of paper B65D5/56 ; linings for domestic water storage heaters F24H1/183
• CPC Class Codes: C08L 2666/16 Addition or condensation polymers of aldehydes or ketones according to C08L59/00 - C08L61/00; Derivatives thereof
• CPC Class Codes: C08L 61/00 Compositions of condensation polymers of aldehydes or ketones with polyalcohols C08L59/00; with polynitriles C08L77/00; Compositions of derivatives of such polymers
• CPC Class Codes: C09D 167/00 Coating compositions based on polyesters obtained by reactions forming a carboxylic ester link in the main chain based on polyester-amides C09D177/12; based on polyester-imides C09D179/08; Coating compositions based on derivatives of such polymers
• CPC Class Codes: C09D 5/106 containing Zn
• CPC Class Codes: Y10T 428/256 Heavy metal or aluminum or compound thereof
• CPC Class Codes: Y10T 428/31511 Of epoxy ether
• CPC Class Codes: Y10T 428/31794 Of cross-linked polyester
• CPC Class Codes: Y10T 428/31797 Next to addition polymer from unsaturated monomers

Abstract

Disclosed are Bisphenol A (BPA), Bisphenol F, Bisphenol A diglycidyl ether (BADGE), and Bisphenol F diglycidyl ether (BFDGE)-free coating compositions for metal substrates including an under-coat composition containing a polyester (co)polymer, and an under-coat cross-linker; and an over-coat composition containing a poly(vinyl chloride) (co)polymer dispersed in a substantially nonaqueous carrier liquid, an over-coat cross-linker, and a functional (meth)acrylic (co)polymer. Also provided is a method of coating a metal substrate using the BPA, BPF, BADGE and BFDGE-free coating system to produce a hardened protective coating useful in fabricating metal storage containers. The coated substrate is particularly useful in fabricating multi-part foodstuffs storage containers with “easy-open” end closures.

Claims

1. A hardenable packaging coating composition, comprising:

an under-coat composition, containing;

a polyester (co)polymer, and

an under-coat cross-linker; and

an over-coat composition, containing;

a poly(vinyl chloride) (co)polymer dispersed in a substantially nonaqueous over-coat carrier liquid,

an over-coat cross-linker, and

a functional (meth)acrylic (co)polymer;

wherein the packaging coating composition is substantially free of mobile BPA, BPF, BADGE and BFDGE.

2. The hardenable packaging coating composition of claim 1, wherein the under-coat composition further contains a substantially nonaqueous under-coat carrier liquid.

3. The hardenable packaging coating composition of claim 1, wherein the over-coat composition is completely free of BPA, BPF, BADGE and BFDGE.

4. The hardenable packaging coating composition of claim 1, wherein the polyester (co)polymer exhibits a hydroxyl number from about one to about 40 milligrams KOH per gram.

5. The hardenable packaging coating composition of claim 1, wherein the polyester (co)polymer exhibits a glass transition temperature of at least about 50°

C.

6. The hardenable packaging coating composition of claim 1, wherein the polyester (co)polymer is present in an amount from about 20 to about 90 percent by weight of the under-coat coating composition on a non-volatile solids basis.

7. The hardenable packaging coating composition of claim 1, wherein the under-coat cross-linker contains two or more functional groups selected from hydroxyl, amino, vinyl and isocyanate groups.

8. The hardenable packaging composition of claim 7, wherein the under-coat cross-linker is selected from the group consisting of phenoplast, aminoplast, and blocked isocyanate cross-linkers.

9. The hardenable packaging coating composition of claim 8, wherein the blocked isocyanate cross-linker has a blocking group selected from 2-butanone oxime, ε

-caprolactam and diethyl malonate; and

the isocyanate is selected from HDI, IPDI, TMXDI, H₁₂MDI and TMI.

10. The hardenable packaging coating composition of claim 1, wherein the under-coat cross-linker is present in an amount from about 5 to about 30 percent by weight of the under-coat composition on a non-volatile solids basis.

11. The hardenable packaging coating composition of claim 1, wherein the poly(vinyl chloride) (co)polymer is dispersed in the substantially nonaqueous carrier liquid in an amount from about 60 to about 85 percent by weight of the over-coat coating composition on a non-volatile solids basis.

12. The hardenable packaging coating composition of claim 1, wherein the over-coat cross-linker contains two or more functional groups selected from hydroxyl, amino and isocyanate groups.

13. The hardenable packaging coating composition of claim 1, wherein the over-coat cross-linker is present in an amount from about 5 to about 30 percent by weight of the over-coat coating composition on a non-volatile solids basis.

14. The hardenable packaging coating composition of claim 1, wherein the functional (meth)acrylic (co)polymer contains at least one functional group selected from the group consisting of hydroxyl, carboxyl, and oxirane.

15. The hardenable packaging coating composition of claim 1, wherein at least one of the under-coat and over-coat compositions further contains from about 0.1 weight percent to about 5 weight percent of a catalyst on a non-volatile solids basis.

16. The hardenable packaging coating composition of claim 1, wherein one or both of the under-coat and over-coat compositions further contains at least one of a hydrogen chloride scavenger or a pigment.

17. The hardenable packaging coating composition of claim 16, wherein the hydrogen chloride scavenger is selected from monooctyl tin mercaptide, dioctyl tin mercaptide, dibutyl tin dilaurate and dibutyl tin maleate;

epoxidized linseed oil, epoxidized soy bean oil, dimer acid DGE and epoxidized polybutadiene; and

the pigment is selected from aluminum flake, titanium dioxide, and zinc oxide.

18. A method of coating a metal substrate with a hardenable packaging system, comprising:

applying an under-coat composition to a metal substrate, said under-coat composition containing;

a polyester (co)polymer, and

an under-coat cross-linker;

applying an over-coat composition to the under-coated metal substrate, said over-coat composition containing;

a poly(vinyl chloride) (co)polymer dispersed in a substantially nonaqueous over-coat carrier liquid,

an over-coat cross-linker, and

a functional (meth)acrylic (co)polymer; and

curing the under-coat and over-coat compositions to provide a hardened film of the under-coat and over-coat compositions on the metal substrate;

wherein the hardenable packaging composition and hardened film are substantially free of mobile BPA, BPF, BADGE and BFDGE.

19. A metal foodstuffs container having at least an interior surface coated with a hardened packaging composition produced according to the method of claim 18.

20. A metal foodstuffs container according to claim 19, wherein the metal foodstuffs container is a multi-part can having at least one easy-open end closure with at least an interior surface of the easy-open end closure coated with a hardened packaging coating according to the method of claim 18.