Container coating compositions

Patent metadata

Field	Value
Publication number	US-10377912-B2
Application number	US-201514645456-A
Country	US
Kind code	B2
Filing date	Mar 12, 2015
Priority date	Mar 12, 2015
Publication date	Aug 13, 2019
Grant date	Aug 13, 2019

Abstract

A coating composition comprising a polyester, a mixture of novolak and resole resins and a vinyl chloride polymer, and the use of these compositions to coat metal containers is disclosed.

First claim

What is claimed is:

1. A coating composition comprising:
(a) 10 to 40 percent by weight of a polyester having a number average molecular weight of at least 15,000, an acid value of below 10 and a hydroxyl value of below 20,
(b) 20 to 40 percent by weight of a phenolplast comprising:
(i) a resole resin,
(ii) a novolak resin prepared by reacting formaldehyde and phenol in a molar ratio of less than about 1:1 in the presence of an acid catalyst,
in which the resin solids weight ratio of (i) to (ii) is from 2.0 to 4.0:1,

(c) 30 to 50 percent by weight of a vinyl chloride polymer;

the percentages by weight being based on weight of resin solids in the coating composition.

2. The coating composition of claim 1 in which the polyester has a number average molecular weight of from 20,000 to 50,000, an acid value of below 7.5 and a hydroxyl value of below 10.

3. The coating composition of claim 1 in which the weight ratio of (i) to (ii) is from 2.5 to 3.5:1.

4. The coating composition of claim 1 in which the vinyl chloride polymer is dispersed in an organic solvent.

5. The coating composition of claim 1 in which the vinyl chloride polymer has an intrinsic viscosity measured in a 1% solution of cyclohexanone at 20° C. of at least 1.0.

6. The coating composition of claim 4 that additionally contains a vinyl chloride interpolymer with maleic acid or anhydride dissolved in an organic solvent.

7. The coating composition of claim 6 in which the vinyl chloride interpolymer has an intrinsic viscosity measured in a 1% by weight solution of cyclohexanone of less than 0.8.

8. The coating composition of claim 6 in which the resin solids weight ratio of vinyl chloride polymer dispersion in organic solvent to vinyl chloride interpolymer dissolved in organic solvent is from 4 to 7:1.

9. The coating composition of claim 1 which is substantially free of bisphenol A and diglycidyl ethers of bisphenol A.

10. The coating composition of claim 1 which is essentially free of bisphenol A and diglycidyl ethers of bisphenol A.

11. The coating composition of claim 1 which is completely free of bisphenol A and diglycidyl ethers of bisphenol A.

12. A method of coating a container comprising:
(a) applying to the substrate a coating composition comprising:
(i) 10 to 40 percent by weight of a polyester having a number average molecular weight of at least 15,000, an acid value of below 10 and a hydroxyl value of below 20,
(ii) 20 to 40 percent by weight of a phenolplast comprising:
(A) a resole resin,
(B) a novolak resin prepared by reacting formaldehyde and phenol in a molar ratio of less than about 1:1 in the presence of an acid catalyst,
in which the resin solids weight ratio of (A) to (B) is from 2.0 to 4.0:1,

(iii) 30 to 50 percent by weight of a vinyl chloride polymer;
the percentages by weight being based on weight of resin solids in the coating composition;

(b) curing the composition on the substrate to form a coating, and
(c) forming a container from the coated substrate.

13. The method of claim 12 in which the substrate is aluminum.

14. The method of claim 12 in which the composition is applied by roll coating to a planar sheet.

15. The method of claim 12 in which the coated planar sheet is slit into body blanks that are then formed into a cylinder and welded at the side seam.

16. A coated container comprising a coating composition applied to at least a portion of the interior surface of the container in which the composition comprises:
(a) 10 to 40 percent by weight of a polyester having a number average molecular weight of at least 15,000, an acid value of below 10 and a hydroxyl value of below 20,
(b) 20 to 40 percent by weight of a phenolplast comprising:
(i) a resole resin,
(ii) a novolak resin prepared by reacting formaldehyde and phenol in a molar ratio of less than about 1:1 in the presence of acid catalyst,
in which the resin solids weight ratio of (i) to (ii) is from 2.0 to 4.0:1,

(c) 30 to 50 percent by weight of a vinyl chloride polymer;
the percentages by weight being based on weight of resin solids in the coating composition.

17. The coated container of claim 16 that is a coated three-piece can.

Assignees

• Ppg Ind Ohio Inc

Inventors

• Mcvay Robert
• Most Christopher
• Kutubuddin Ayaz

Classifications

• B23K2101/34

  Coated articles {; Surface treated articles} · CPC title

• B05D1/28 Primary

  performed by transfer from the surfaces of elements carrying the liquid or other fluent material, e.g. brushes, pads, rollers · CPC title

• B65D7/04

  of curved cross-section, e.g. cans of circular or elliptical cross-section (thermally insulated B65D81/3813, B65D81/3837) · CPC title

• C08L2205/025

  containing two or more polymers of the same hierarchy C08L, and differing only in parameters such as density, comonomer content, molecular weight, structure · CPC title

• B23K2103/04

  Steel {or steel} alloys · CPC title