Coating compositions for cans and methods of coating

• US 20060100366A1
• Filed: 10/18/2005
• Published: 05/11/2006
• Est. Priority Date: 10/20/2004
• Status: Active Grant

• Current Assignee: Sherwin-Williams Company
• Original Assignee: Valspar Sourcing, Inc. (Sherwin-Williams Company)
• Inventors: O'Brien, Robert M., Evans, Richard H., Rardon, Daniel E., Bartley, George K. III, Spynda, Rachael Ann
• Granted Patent: US 7,592,047 B2
• Time in Patent Office: Days
• US Class Current: 524/800
• CPC Class Codes: B05D 1/02 performed by spraying
• CPC Class Codes: B05D 2202/00 Metallic substrate
• CPC Class Codes: B05D 2202/20 based on light metals
• CPC Class Codes: B05D 2202/25 based on Al
• CPC Class Codes: B05D 2254/00 Tubes
• CPC Class Codes: B05D 2254/04 Applying the material on the interior of the tube
• CPC Class Codes: B05D 2259/00 Applying the material to the internal surface of hollow articles other than tubes
• CPC Class Codes: B05D 2401/21 Mixture of organic solvent and water
• CPC Class Codes: B05D 2520/05 Latex
• CPC Class Codes: B05D 3/007 After-treatment
• CPC Class Codes: B05D 7/227 of containers, cans or the like
• CPC Class Codes: B32B 15/04 comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material next to a bituminous or tarry layer B32B11/08; next to a water-setting substance layer B32B13/06; next to a glass layer B32B17/061; next to a cellulosic plastic layer B32B23/042
• CPC Class Codes: B32B 15/06 of natural rubber or synthetic rubber
• CPC Class Codes: B32B 15/20 comprising aluminium or copper B32B15/016 and B32B15/017 take precedence
• CPC Class Codes: B32B 27/00 Layered products comprising a layer of synthetic resin fibrous or filamentary layer made of a synthetic resin B32B5/02; particulate layer made of a synthetic resin B32B5/16; foamed layer made of a synthetic resin B32B5/18
• CPC Class Codes: B65D 17/00 Rigid or semi-rigid containers specially constructed to be opened by cutting or piercing, or by tearing of frangible members or portions containers made of paper B65D3/00, B65D5/00; frangible inner closure members associated with caps, lids or covers B65D51/20
• 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: C08F 2/22 Emulsion polymerisation
• CPC Class Codes: C08F 212/08 Styrene
• CPC Class Codes: C08F 220/16 of phenols or of alcohols containing two or more carbon atoms
• CPC Class Codes: C08F 220/1802 : C2-(meth)acrylate, e.g. ethyl (meth)acrylate
• 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 220/1811 : C10or C11-(Meth)acrylate, e.g. isodecyl (meth)acrylate, isobornyl (meth)acrylate or 2-naphthyl (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: C08F 220/32 : containing epoxy radicals
• CPC Class Codes: C08F 220/325 : containing glycidyl radical, e.g. glycidyl (meth)acrylate
• CPC Class Codes: C08F 220/58 : containing oxygen in addition to the carbonamido oxygen , e.g. N-methylolacrylamide, N-(meth)acryloylmorpholine
• CPC Class Codes: C08F 220/60 : containing nitrogen in addition to the carbonamido nitrogen
• CPC Class Codes: C08F 265/00 : Macromolecular compounds obtained by polymerising monomers on to polymers of unsaturated monocarboxylic acids or derivatives thereof as defined in group C08F20/00
• CPC Class Codes: C08F 265/02 : on to polymers of acids, salts or anhydrides
• CPC Class Codes: C08F 265/04 : on to polymers of esters
• CPC Class Codes: C08F 265/06 : Polymerisation of acrylate or methacrylate esters on to polymers thereof
• CPC Class Codes: C08F 265/10 : on to polymers of amides or imides
• CPC Class Codes: C08F 283/006 : on to polymers provided for in C08G18/00 C08F283/004 takes precedence
• CPC Class Codes: C08F 283/02 : on to polycarbonates or saturated polyesters C08F283/004 takes precedence
• CPC Class Codes: C08F 291/00 : Macromolecular compounds obtained by polymerising monomers on to macromolecular compounds according to more than one of the groups C08F251/00 - C08F289/00
• CPC Class Codes: C08L 2666/02 : Organic macromolecular compounds, natural resins, waxes or and bituminous materials
• CPC Class Codes: C09D 133/068 : containing glycidyl groups
• CPC Class Codes: C09D 133/14 : of esters containing halogen, nitrogen, sulfur or oxygen atoms in addition to the carboxy oxygen
• CPC Class Codes: C09D 151/003 : grafted on to macromolecular compounds obtained by reactions only involving unsaturated carbon-to-carbon bonds C09D151/04, C09D151/06 take precedence
• CPC Class Codes: C09D 151/08 : grafted on to macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
• CPC Class Codes: C09D 4/06 : Organic non-macromolecular compounds having at least one polymerisable carbon-to-carbon unsaturated bond in combination with a macromolecular compound other than an unsaturated polymer of groups C09D159/00 - C09D187/00
• CPC Class Codes: C23C 4/12 : characterised by the method of spraying
• CPC Class Codes: Y10S 525/922 : Polyepoxide polymer having been reacted to yield terminal ethylenic unsaturation
• CPC Class Codes: Y10S 525/93 : Reaction product of a polyhydric phenol and epichlorohydrin or diepoxide, having a molecular weight of over 5,000, e.g. phenoxy resins
• CPC Class Codes: Y10T 428/1352 : Polymer or resin containing [i.e., natural or synthetic]
• CPC Class Codes: Y10T 428/1355 : Elemental metal containing [e.g., substrate, foil, film, coating, etc.]
• CPC Class Codes: Y10T 428/1386 : Natural or synthetic rubber or rubber-like compound containing
• CPC Class Codes: Y10T 428/139 : Open-ended, self-supporting conduit, cylinder, or tube-type article
• CPC Class Codes: Y10T 428/1393 : Multilayer [continuous layer]
• CPC Class Codes: Y10T 428/31551 : Of polyamidoester [polyurethane, polyisocyanate, polycarbamate, etc.]
• CPC Class Codes: Y10T 428/31678 : Of metal
• CPC Class Codes: Y10T 428/31681 : Next to polyester, polyamide or polyimide [e.g., alkyd, glue, or nylon, etc.]
• CPC Class Codes: Y10T 428/31688 : Next to aldehyde or ketone condensation product
• CPC Class Codes: Y10T 428/31692 : Next to addition polymer from unsaturated monomers
• CPC Class Codes: Y10T 428/31696 : Including polyene monomers [e.g., butadiene, etc.]
• CPC Class Codes: Y10T 428/31699 : Ester, halide or nitrile of addition polymer
• CPC Class Codes: Y10T 428/31855 : Of addition polymer from unsaturated monomers

Abstract

A coating composition for a food or beverage can that includes an emulsion polymerized latex polymer formed by combining an ethylenically unsaturated monomer component with an aqueous dispersion of a salt of an acid- or anhydride-functional polymer and an amine, preferably, a tertiary amine.

Claims

1. A method of coating a food or beverage can, the method comprising:

forming a composition comprising an emulsion polymerized latex polymer, comprising;

forming a salt of an acid- or anhydride-functional polymer and an amine in a carrier comprising water to form an aqueous dispersion;

combining an ethylenically unsaturated monomer component with the aqueous dispersion; and

polymerizing the ethylenically unsaturated monomer component in the presence of the aqueous dispersion to form an emulsion polymerized latex polymer; and

applying the composition comprising the emulsion polymerized latex polymer to a metal substrate prior to or after forming the metal substrate into a food or beverage can or portion thereof.

2. The method of claim 1 wherein applying the composition -to a metal substrate comprises applying the composition to the metal substrate in the form of a planar coil or sheet, hardening the emulsion polymerized latex polymer, and forming the substrate into a food or beverage can or portion thereof.

3. The method of claim 2 wherein forming the substrate into a can or portion thereof comprises forming the substrate into a can end or a can body.

4. The method of claim 2 wherein the can is a 2-piece drawn food can, 3-piece food can, food can end, drawn and ironed can, beverage can end, and the like.

5. The method of claim 1 wherein the metal substrate comprises steel or aluminum.

6. The method of claim 1 wherein applying the composition to a metal substrate comprises applying the composition to the metal substrate after the metal substrate is formed into a can or portion thereof.

7. The method of claim 1 wherein combining an ethylenically unsaturated monomer component with the aqueous dispersion comprises adding the ethylenically unsaturated monomer component to the aqueous dispersion.

8. The method of claim 7 wherein the ethylenically unsaturated monomer component is added incrementally to the aqueous dispersion.

9. The method of claim 1 wherein the ethylenically unsaturated monomer component comprises a mixture of monomers.

10. The method of claim 9 wherein the mixture of monomers comprises at least one oxirane functional group-containing monomer.

11. The method of claim 10 wherein the mixture of monomers comprises at least one oxirane functional group-containing alpha, beta-ethylenically unsaturated monomer.

12. The method of claim 10 wherein the oxirane functional group-containing monomer is present in the ethylenically unsaturated monomer component in an amount of at least 0.1 wt-%, based on the weight of the monomer mixture.

13. The method of claim 10 wherein the oxirane functional group-containing monomer is present in the ethylenically unsaturated monomer component in an amount of no greater than 30 wt-%, based on the weight of the monomer mixture.

14. The method of claim 1 further comprising combining the emulsion polymerized latex polymer with one or more crosslinkers, fillers, catalysts, dyes, pigments, toners, extenders, lubricants, anticorrosion agents, flow control agents, thixotropic agents, dispersing agents, antioxidants, adhesion promoters, light stabilizers, organic solvents, surfactants, or combinations thereof in the coating composition.

15. The method of claim 1 wherein acid-functional polymer has a number average molecular weight of 1500 to 50,000.

16. The method of claim 1 wherein the composition is substantially free of mobile BPA and aromatic glycidyl ether compounds.

17. The method of claim 16 wherein the composition is substantially free of bound BPA and aromatic glycidyl ether compounds.

18. The method of claim 1 wherein the acid- or anhydride-functional polymer comprises an acid- or anhydride-functional acrylic polymer, acid- or anhydride-functional alkyd resin, acid- or anhydride-functional polyester resin, acid- or anhydride-functional polyurethane, or combinations thereof.

19. The method of claim 18 wherein the acid- or anhydride-functional polymer comprises an acid-functional acrylic polymer.

20. The method of claim 18 wherein the acid- or anhydride-functional polymer comprises a polyester polymer.

21. The method of claim 20 wherein the polyester polymer comprises one or more segments of Formula I:

—

O—

Ar—

R_n—

C(O)—

O—

R¹—

O—

C(O)—

R_n—

Ar—

O—

wherein;

each Ar is independently a divalent aryl group or heteroarylene group;

each R is independently a divalent organic group;

R¹ is a divalent organic group; and

each n is 0 or 1.

22. The method of claim 1 wherein the amine is a tertiary amine.

23. The method of claim 22 wherein the tertiary amine is selected from the group consisting of trimethyl amine, dimethylethanol amine, methyidiethanol amine, triethanol amine, ethyl methyl ethanol amine, dimethyl ethyl amine, dimethyl propyl amine, dimethyl 3-hydroxy-1-propyl amine, dimethylbenzyl amine, dimethyl 2-hydroxy-1-propyl amine, diethyl methyl amine, dimethyl 1-hydroxy-2-propyl amine, triethyl amine, tributyl amine, N-methyl morpholine, and mixtures thereof.

24. The method of claim 1 wherein the acid- or anhydride-functional polymer is at least 25% neutralized with the amine in water.

25. The method of claim 1 wherein the ethylenically unsaturated monomer component is polymerized in the presence of the aqueous dispersion with a water-soluble free radical initiator at a temperature of 0°

C. to 100°

C.

26. The method of claim 25 wherein the free radical initiator comprises a peroxide initiator.

27. The method of claim 26 wherein the free radical initiator comprises hydrogen peroxide and benzoin.

28. The method of claim 25 wherein the free radical initiator comprises a redox initiator system.

29. The method of claim 1 wherein the aqueous dispersion further comprises an organic solvent.

30. The method of claim 29 further comprising removing at least a portion of the organic solvent.

32. A food or beverage can prepared by the method of claim 1.

31. A method of coating a food or beverage can, the method comprising:

forming a composition comprising an emulsion polymerized latex polymer, comprising;

forming a salt of an acid- or anhydride-functional polymer and a tertiary amine in a carrier comprising water to form an aqueous dispersion;

combining an ethylenically unsaturated monomer component comprising 0.1 wt-% to 30 wt-% of an oxirane-functional alpha, beta-ethylenically unsaturated monomer with the aqueous dispersion, based on the weight of the monomer component; and

polymerizing the ethylenically unsaturated monomer component in the presence of the aqueous dispersion to form an emulsion polymerized latex polymer; and

applying the composition comprising the emulsion polymerized latex polymer to a metal substrate prior to or after forming the metal substrate into a food or beverage can or portion thereof.

33. A food or beverage can prepared by the method of claim 31.

39. The can of claim 33 wherein the acid- or anhydride-functional polymer comprises an acid- or anhydride-functional acrylic polymer, acid- or anhydride-functional alkyd resin, acid- or anhydride-functional polyester resin, acid- or anhydride-functional polyurethane, or combinations thereof.

40. The can of claim 39 wherein the acid- or anhydride-functional polymer comprises an acid-functional acrylic polymer.

41. The can of claim 33 wherein the amine is a tertiary amine.

34. A food or beverage can comprising:

a body portion or an end portion comprising a metal substrate; and

a coating composition disposed thereon, wherein the coating composition comprises an emulsion polymerized latex polymer, wherein the emulsion polymerized latex polymer is prepared from a salt of an acid- or anhydride-functional polymer and an amine, an ethylenically unsaturated monomer component, and water.

35. The can of claim 34 wherein the ethylenically unsaturated monomer component comprises a mixture of monomers.

36. The can of claim 35 wherein the mixture of monomers comprises at least one oxirane functional group-containing monomer.

37. The can of claim 36 wherein the mixture of monomers comprises at least one oxirane functional group-containing alpha, beta-ethylenically unsaturated monomer.

38. The can of claim 36 wherein the oxirane functional group-containing monomer is present in the ethylenically unsaturated monomer component in an amount of 0.1 wt-% to 30 wt-%, based on the weight of the monomer mixture.

42. A composition for use in coating a food or beverage can, the composition comprising an emulsion polymerized latex polymer, wherein the emulsion polymerized latex polymer is prepared from a salt of an acid- or anhydride-functional polymer and an amine, an ethylenically unsaturated monomer component, and water.