Thermoset undercoating compositions compatible with free-radically cured overcoating for metal substrates
AssigneeSwimc LLC
InventorsJean-Dominique Turgis, Marie Edith Quereau
Life of this patent
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Abstract
A thermoset undercoating composition for a food or beverage container or other packaging container, the thermoset undercoating composition comprising a binder polymer, an adhesion promoting additive comprising an aminoplast resin having at least one reactive group having an ethylenically unsaturated double bond that is reactive under free-radical curing conditions, an optional crosslinker configured to react with the binder polymer upon thermal curing of the thermoset undercoating composition, wherein the optional crosslinker preferably does not include groups that are reactive under free-radical curing conditions, and a liquid carrier.
Claims20
A thermoset undercoating composition for a food or beverage container, the thermoset undercoating composition comprising:
- a binder polymer;
- an adhesion promoting additive comprising an aminoplast resin having at least one reactive group having an ethylenically unsaturated double bond that is reactive under free-radical curing conditions;
- a crosslinker configured to react with the binder polymer upon thermal curing of the thermoset undercoating composition, wherein the crosslinker does not include groups that are reactive under free-radical curing conditions;
- and
- a liquid carrier.
A method of forming a packaging article, the method comprising the steps of:
- coating at least a portion of a metal substrate for a food or beverage container with a thermoset undercoating composition, the thermoset undercoating composition comprising:
- a binder polymer;
- a crosslinker configured to react with the binder polymer upon thermal curing of the thermoset undercoating composition, wherein the crosslinker does not include groups that are reactive under free-radical curing conditions;
- and
- an adhesion promoting additive comprising an aminoplast resin having at least one reactive group having an ethylenically unsaturated double bond that is reactive under free-radical curing conditions;
- thermally drying or curing the thermoset undercoating composition to form a cured thermoset undercoating on the metal substrate;
- coating the dried or cured thermoset undercoating with a second coating composition comprising at least one of a free-radically curable composition or a thermally curable composition;
- and
- curing the second coating composition to form at least one additional coating on the thermoset undercoating.
A packaging article for a food or beverage container, the article comprising:
- a container, or a portion thereof, comprising:
- a metal substrate;
- and
- a multi-layer coating system applied on at least a portion of the metal substrate, the multi-layer coating system comprising:
- (i) a dried or cured thermoset undercoating derived from a thermoset undercoating composition, the thermoset undercoating composition comprising:
- a binder polymer;
- a crosslinker configured to react with the binder polymer upon thermal curing of the thermoset undercoating composition, wherein the crosslinker does not include groups that are reactive under free-radical curing conditions;
- and
- an adhesion promoting additive comprising an aminoplast resin having at least one reactive group having an ethylenically unsaturated double bond that is reactive under free-radical curing conditions;
- and
- (ii) at least one additional coating on the dried or cured thermoset undercoating, the at least one additional coating derived from a second coating composition comprising at least one of a free-radically curable composition or a thermally curable composition.
Dependencies are inferred from the claim text.