Bisphenol A and aromatic glycidyl ether-free coatings
View Patent ↗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.
1. A metal closure for a food or beverage container, the metal closure comprising:
a metal substrate;
a multi-layer food-contact coating adhered to an interior surface of the metal substrate, the coating comprising:
an under-coat layer formed from an under-coat composition comprising:
a polyester (co)polymer, and
an under-coat cross-linker; and
an over-coat layer formed from an over-coat composition comprising finely divided poly(vinyl chloride) (co)polymer particles dispersed in a substantially nonaqueous carrier liquid to form an organosol, wherein the over-coat composition includes from about 40 to about 90 percent by weight, on a non-volatile solids basis, of the poly(vinyl chloride) (co)polymer;
wherein the over-coat and under-coat layers are completely free of BPA, BPF, BADGE and BFDGE.
2. The metal closure of claim 1 , wherein the under-coat cross-linker comprises a phenolic cross-linker.
3. The metal closure of claim 2 , wherein the phenolic cross-linker is a resole type phenolic cross-linker.
4. The metal closure of claim 1 , wherein the under-coat composition includes from about 20 to about 99 percent by weight, on a non-volatile solids basis, of the polyester (co)polymer.
5. The metal closure of claim 4 , wherein the under-coat composition includes from about 5 to about 30 percent by weight of phenolic cross-linker, based on the total non-volatile solids in the under-coat composition.
6. The metal closure of claim 1 , wherein the under-coat composition includes from about 60 to about 99 percent by weight, on a non-volatile solids basis, of the polyester (co)polymer.
7. The metal closure of claim 4 , wherein the polyester (co)polymer exhibits a glass transition temperature of greater than 50° C.
8. The metal closure of claim 1 , wherein the polyester (co)polymer exhibits a glass transition temperature of greater than 60° C.
9. The metal closure of claim 1 , wherein the coating is completely free of NOGE.
10. The metal closure of claim 1 , wherein the coating is an aromatic glycidyl ether-free coating.
11. The metal closure of claim 1 , wherein the coating is a two-layer coating.
12. A food or beverage container including the metal closure of claim 1 , wherein the container contains a packaged food or beverage product.
13. A metal closure for a food or beverage container, comprising:
a metal substrate;
a two-layer food-contact coating adhered to an interior surface of the metal substrate, the multi-layer coating comprising:
an under-coat layer formed from an under-coat composition comprising:
from about 20 to about 99 percent by weight, on a non-volatile solids basis, of a polyester (co)polymer, and
from about 5 to about 30 percent by weight, on a non-volatile solids basis, of a phenolic cross-linker; and
an over-coat layer formed from an over-coat composition comprising finely divided poly(vinyl chloride) (co)polymer particles dispersed in a substantially nonaqueous carrier liquid to form an organosol, wherein the over-coat composition includes from about 40 to about 90 percent by weight, on a non-volatile solids basis, of the poly(vinyl chloride) (co)polymer;
wherein the coating is completely free of BPA, BPF, BADGE, BFDGE, and NOGE.
14. The metal closure of claim 13 , wherein the polyester (co)polymer exhibits a glass transition temperature of greater than 50° C.