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EP4581088A1 - Compositions de revêtement comprenant un polymère acrylique et un agent de réticulation phénolique, articles, polymères acryliques et procédés - Google Patents

Compositions de revêtement comprenant un polymère acrylique et un agent de réticulation phénolique, articles, polymères acryliques et procédés

Info

Publication number
EP4581088A1
EP4581088A1 EP23861313.7A EP23861313A EP4581088A1 EP 4581088 A1 EP4581088 A1 EP 4581088A1 EP 23861313 A EP23861313 A EP 23861313A EP 4581088 A1 EP4581088 A1 EP 4581088A1
Authority
EP
European Patent Office
Prior art keywords
coating composition
acrylic polymer
acid
acrylic
functional
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP23861313.7A
Other languages
German (de)
English (en)
Inventor
Yingchao Zhang
Nusrah HUSSAIN
Danielle METZGER
Daniel DEMARCHI
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Swimc LLC
Original Assignee
Swimc LLC
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Swimc LLC filed Critical Swimc LLC
Publication of EP4581088A1 publication Critical patent/EP4581088A1/fr
Pending legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D161/00—Coating compositions based on condensation polymers of aldehydes or ketones; Coating compositions based on derivatives of such polymers
    • C09D161/04—Condensation polymers of aldehydes or ketones with phenols only
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F212/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an aromatic carbocyclic ring
    • C08F212/02—Monomers containing only one unsaturated aliphatic radical
    • C08F212/04—Monomers containing only one unsaturated aliphatic radical containing one ring
    • C08F212/06—Hydrocarbons
    • C08F212/08—Styrene
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D125/00—Coating compositions based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an aromatic carbocyclic ring; Coating compositions based on derivatives of such polymers
    • C09D125/02—Homopolymers or copolymers of hydrocarbons
    • C09D125/04—Homopolymers or copolymers of styrene
    • C09D125/08—Copolymers of styrene
    • C09D125/14—Copolymers of styrene with unsaturated esters
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D133/00—Coating compositions based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Coating compositions based on derivatives of such polymers
    • C09D133/02—Homopolymers or copolymers of acids; Metal or ammonium salts thereof
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D133/00—Coating compositions based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Coating compositions based on derivatives of such polymers
    • C09D133/04—Homopolymers or copolymers of esters
    • C09D133/06—Homopolymers or copolymers of esters of esters containing only carbon, hydrogen and oxygen, the oxygen atom being present only as part of the carboxyl radical
    • C09D133/062—Copolymers with monomers not covered by C09D133/06
    • C09D133/066—Copolymers with monomers not covered by C09D133/06 containing -OH groups

Definitions

  • coatings for use on food or beverage containers should avoid unsuitably altering the taste of the packaged food or beverage products, and should also avoid flaking or chipping into the packaged products.
  • the coatings should also resist chemically aggressive food or beverage products (which can have a complex chemical profile, including salts, acids, sugars, fats, etc.) for extended periods of time (e.g., years).
  • Food or beverage container coatings should also have good adhesion to the underlying substrate (e.g., metal substrate) and remain sufficiently flexible after curing. This is because subsequent fabrication and denting during transportation, 1 ⁇ ⁇ storage, or use (e.g., by dropping) may cause the metal substrate to deform, which will cause the coating to flex.
  • Polyester-based coatings suitable for food contact that have exhibited both good fabrication properties and an absence of crazing, have tended to be too soft and exhibit unsuitable corrosion resistance. Conversely, polyester-based coatings suitable for food contact that have exhibited good corrosion resistance have typically exhibited poor flexibility and unsuitable crazing when fabricated. Accordingly, it will be appreciated that what is needed in the art are improved coating compositions that exhibit the stringent balance of coating properties to permit the use of such coating compositions on food or beverage containers.
  • the present disclosure provides aqueous food or beverage container coating compositions, articles having a coating formed from such compositions (e.g., coated metal substrates and metal 2 ⁇ ⁇ packaging formed from such substrates), and methods (e.g., methods of making a coating composition and methods of coating such composition).
  • the aqueous food or beverage container coating compositions (preferably, food container coating compositions) described herein include: an acid- or anhydride functional acrylic polymer, preferably at least 50 weight percent (wt-%), based on total resin solids, of the acid- or anhydride functional acrylic polymer, and preferably the acid- or anhydride functional polymer is at least partially neutralized; a phenolic crosslinker; and an aqueous liquid carrier.
  • the present disclosure also provides an at least partially neutralized acid- or anhydride-functional acrylic polymer.
  • the present disclosure also provides acrylic polymers.
  • an acid- or anhydride-functional organic-solution polymerized acrylic polymer preferably an at least partially neutralized acid- or anhydride-functional organic-solution polymerized acrylic polymer, as described herein for use in an aqueous coating composition, is provided.
  • an at least partially neutralized acid- or anhydride-functional organic-solution polymerized acrylic polymer is provided that includes interpolymerized monomers including (meth)acrylic acid monomers, wherein the acrylic polymer is hydroxyl-functional, has a calculated acid number of less than 60 mg KOH per gram resin, and is self-dispersible in water.
  • the acrylic polymer is crosslinked with at least 5 wt-% resole phenolic crosslinker, based on total resin solids.
  • the present disclosure also provides coated metal substrates and metal packaging formed from such coated metal substrates.
  • a coated metal substrate is provided that includes a metal substrate having a cured adherent coating disposed on at least a portion of a surface thereof, wherein the coating is formed from an aqueous coating composition described herein.
  • a coated metal substrate in a preferred embodiment, includes a metal substrate having a cured adherent coating disposed on at least a portion of a surface thereof, wherein the coating is formed from an aqueous food container coating composition including: at least 50 wt-%, based on total resin solids, of an at least partially neutralized acid- or anhydride- functional organic-solution polymerized acrylic polymer; at least 5 wt-%, preferably at least 20 wt- %, of crosslinker including one or more phenolic crosslinkers, based on total resin solids; and an aqueous liquid carrier.
  • the acrylic polymer is hydroxyl-functional, has a calculated acid number of less than 60 mg KOH per gram resin, and is self-dispersible in water. 3 ⁇ ⁇
  • the present disclosure also provides methods.
  • a method of forming an aqueous food or beverage coating composition (preferably, an aqueous food container coating composition) as described herein is provided, wherein the method includes: polymerizing an ethylenically unsaturated monomer component in organic solvent to form an acid- or anhydride- functional acrylic polymer having a calculated acid number of less than 60 mg KOH per gram polymer; preferably, at least partially neutralizing the acid- or anhydride-functional acrylic polymer with a fugitive base; forming a mixture of the acid- or anhydride functional polymer or the at least partially neutralized acid- or anhydride-functional acrylic polymer with a phenolic crosslinker; and combining the mixture with water to form an aqueous coating composition that includes (i) at least 50 wt-%
  • a method of coating a food or beverage container includes: providing an aqueous food or beverage container coating composition as described herein; causing the coating composition to be applied to at least a portion of a metal substrate prior to or after forming the metal substrate into a food or beverage container or portion thereof; and thermally curing the coating composition to form a cured coating.
  • metal packaging refers to a food or beverage container (e.g., can or cup), portion thereof, or metal closure, or pull tab for an easy open end.
  • a food or beverage “container” is used to encompass containers such as pails or drums in addition to conventional cans and cups.
  • the term “food-contact surface” refers to a surface of an article (e.g., a food can) intended for prolonged contact with a food product.
  • the term “beverage-contact surface” refers to a surface of an article (e.g., a beverage can) intended for prolonged contact with a beverage product.
  • the terms “food contact surface” and “beverage contact surface” generally refers to an interior metal surface of the container that would be expected to contact the food/beverage product in the absence of a coating composition applied thereon.
  • a base layer, intermediate layer, and/or top-coat layer applied on an interior surface of a metal food/beverage can is considered to be applied on a food-contact/beverage-contact surface of the can. 4 ⁇ ⁇
  • the term “on,” when used in the context of a coating applied on a surface or substrate, includes both coatings applied directly (e.g., virgin metal or pre-treated metal such as electroplated steel) or indirectly (e.g., on a primer layer) to the surface or substrate.
  • a coating applied to a pre-treatment layer e.g., formed from a chrome or chrome-free pretreatment
  • a primer layer overlying a substrate constitutes a coating applied on (or disposed on) the substrate.
  • a “cured” coating refers to one wherein the polymer is covalently cured via a crosslinking reaction (e.g., a thermoset coating), and adhered to a metal substrate, thereby forming a coated metal substrate.
  • An “adherent” coating refers to a cured coating that adheres (i.e., is fixed) to a substrate, such as a metal substrate, preferably according to the Adhesion Test described in the Test Methods (ASTM D3359-17). Preferably, an adhesion rating of at least 4B is considered to be adherent.
  • the term “substantially free” of a particular component means that the compositions or cured coatings of the present disclosure contain less than 1,000 parts per million (ppm) of the recited component, if any.
  • compositions or cured coatings of the present disclosure contain less than 100 parts per million (ppm) of the recited component, if any.
  • essentially completely free of a particular component means that the compositions or cured coatings of the present disclosure contain less than 10 parts per million (ppm) of the recited component, if any.
  • completely free of a particular component means that the compositions or cured coatings of the present disclosure contain less than 20 parts per billion (ppb) of the recited component, if any.
  • composition or cured coating that may contain a recited component, if any, means that the composition or cured coating contains less than the pertinent ppm or ppb maximum threshold for the component regardless of the context of the component in the composition or cured coating (e.g., regardless of whether the compound is present in unreacted form, in reacted form as a structural unit of another material, or a combination thereof).
  • total resin solids refers to the nonvolatile organic content of the coating composition, which includes the polymer solids content of the resin as well as other nonvolatile organic additives, e.g., lubricants (but not organic solvent).
  • inorganic materials e.g., fillers or pigments
  • the total resin solids can be calculated based on the starting materials. If a calculation is not possible due to lack of information, inorganic material and water 5 ⁇ ⁇ and organic solvent content can be determined using Thermogravimetric Analysis (TGA), which removes the organic material and water, thereby leaving the inorganic material, and one of skill in the art can back-calculate to determine the amount of total resin solids.
  • TGA Thermogravimetric Analysis
  • polymer and “polymeric material” include, but are not limited to, organic homopolymers, copolymers, such as for example, block, graft, statistical, including random, and alternating copolymers, terpolymers, etc., and blends and modifications thereof.
  • polymer shall include all possible geometrical configurations of the material. These configurations include, but are not limited to, isotactic, syndiotactic, and atactic symmetries.
  • the term “comprises” and variations thereof do not have a limiting meaning where these terms appear in the description and claims.
  • the phrase “consisting essentially of” indicates that the listed elements are required or mandatory, but that other elements are optional and may, or may not, be present depending upon whether or not they materially affect the activity or action of the listed elements.
  • the words “preferred” and “preferably” refer to embodiments of the disclosure that may afford certain benefits, under certain circumstances. However, other embodiments may also be preferred, under the same or other circumstances.
  • the term “or” is generally employed in its usual sense including “and/or” unless the content clearly dictates otherwise.
  • the term “and/or” means one or all of the listed elements or a combination of any two or more of the listed elements.
  • all numbers are assumed to be modified by the term “about” and in certain embodiments, preferably, by the term “exactly.”
  • the term “about” refers to that variation in the measured quantity as would be expected by the skilled artisan making the measurement and exercising a level of care commensurate with the objective of the measurement and the precision of the measuring equipment used.
  • “up to” a number includes the number (e.g., 50).
  • a number e.g., at least 50
  • no more than a number e.g., no more than 50
  • the recitations of numerical ranges by endpoints include all numbers subsumed within that range as well as the endpoints (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, 5, etc.).
  • the term “room temperature” or “ambient temperature” refers to a temperature of 20 ⁇ C to 25 ⁇ C.
  • the term “in the range” or “within a range” includes the endpoints of the stated range.
  • Aqueous food or beverage container coating compositions described herein include: an acid- or anhydride-functional acrylic polymer; a phenolic crosslinker; and an aqueous liquid carrier.
  • aqueous food or beverage containing coating compositions described herein include: at least 50 wt-%, based on total resin solids, of an at least partially neutralized acid- or anhydride-functional acrylic polymer; a phenolic crosslinker; and an aqueous liquid carrier.
  • the present disclosure also provides an at least partially neutralized acid- or anhydride-functional acrylic polymer, which is preferably crosslinkable with a phenolic crosslinker upon coating cure conditions.
  • Acrylic Polymers The present disclosure provides an acid- or anhydride-functional acrylic polymer, preferably an at least partially neutralized acid- or anhydride functional acrylic polymer, and aqueous coating compositions that include such polymer, which is preferably crosslinked with a phenolic crosslinker.
  • An acrylic polymer is a polymer that is formed from, that is, polymerized from, a variety of acid- or anhydride-functional monomers, or salts thereof; their selection is dependent on the desired 8 ⁇ ⁇ final polymer properties.
  • such monomers are ethylenically unsaturated, more preferably, alpha, beta-ethylenically unsaturated.
  • Suitable ethylenically unsaturated acid- or anhydride-functional monomers for use in forming the acrylic polymer described herein include monomers having a reactive carbon-carbon double bond and an acidic or anhydride group, or salts thereof.
  • Preferred such monomers have from 3 to 20 carbons, at least 1 site of unsaturation, and at least 1 acid or anhydride group, or salt thereof.
  • Suitable acid-functional monomers include ethylenically unsaturated acids (mono-protic or diprotic), anhydrides or monoesters of a dibasic acid, which are copolymerizable with the optional other monomer(s) used to prepare the polymer.
  • Illustrative monobasic acids are those represented by the structure CH 2 ⁇ C(R 1 )—COOH, where R 1 is hydrogen or an alkyl radical of 1 to 6 carbon atoms, and typically hydrogen or a methyl group.
  • Suitable dibasic acids are those represented by the formulas R 2 (COOH)C ⁇ C(COOH)R 3 and R 2 (R 4 )C ⁇ C(COOH)R 3 COOH, where R 2 and R 3 are hydrogen, an alkyl radical of 1-8 carbon atoms, halogen, cycloalkyl of 3 to 7 carbon atoms or phenyl, and R 6 is an alkylene radical of 1 to 6 carbon atoms.
  • Half-esters of these acids with alkanols of 1 to 8 carbon atoms are also suitable.
  • Non-limiting examples of useful ethylenically unsaturated acid-functional monomers include acids such as, for example, acrylic acid, methacrylic acid, alpha-chloroacrylic acid, alpha- cyanoacrylic acid, crotonic acid, alpha-phenylacrylic acid, beta-acryloxypropionic acid, fumaric acid, maleic acid, sorbic acid, alpha-chlorosorbic acid, angelic acid, cinnamic acid, p- chlorocinnamic acid, beta-stearylacrylic acid, citraconic acid, mesaconic acid, glutaconic acid, aconitic acid, tricarboxyethylene, 2-methyl maleic acid, itaconic acid, 2-methyl itaconic acid, methyleneglutaric acid, and the like, or mixtures thereof.
  • acids such as, for example, acrylic acid, methacrylic acid, alpha-chloroacrylic acid, alpha- cyanoacrylic acid, crotonic acid, al
  • Preferred unsaturated acid-functional monomers include acrylic acid, methacrylic acid, crotonic acid, fumaric acid, maleic acid, 2-methyl maleic acid, itaconic acid, 2-methyl itaconic acid, and mixtures thereof. More preferred unsaturated acid-functional monomers include acrylic acid, methacrylic acid, crotonic acid, fumaric acid, maleic acid, itaconic acid, and mixtures thereof. Most preferred unsaturated acid-functional monomers include acrylic acid, methacrylic acid, and mixtures thereof.
  • Other certain acid -functional monomers include phosphorus-containing (e.g., phosphoric acid-functional or phosphonic acid-functional) monomers and sulfur-containing (e.g., sulfonic acid- functional) monomers.
  • Nonlimiting examples of suitable ethylenically unsaturated anhydride monomers include compounds derived from the above acids (e.g., as pure anhydride or mixtures of such).
  • Preferred anhydrides include acrylic anhydride, methacrylic anhydride, and maleic anhydride. If desired, aqueous salts of the above acids may also be employed.
  • the acrylic polymer includes acid- or anhydride-functional groups, at least some of which are neutralized to form salt groups.
  • meth(acrylic) monomers include an acid group.
  • the polymers of the present disclosure may include monomers that include acid groups that are not (meth)acrylic monomers, including, for example, sorbic acid.
  • Acrylic polymers with such groups are used to encapsulate and stabilize the phenolic crosslinker.
  • Acrylic polymers are typically, and preferably, synthesized using radical polymerization (also referred to as free-radical polymerization).
  • radical polymerization also referred to as free-radical polymerization
  • the viscosity of and/or the homogeneity of the solution including the solvent medium often results in low (e.g., polymers with a weight average molecular weight (Mw) or number average molecular weight (Mn) that is typically less than 50,000 Da, more often less than 15,000 Da, and in some embodiments, less than 10,000 Da) or medium (e.g., polymers with an Mw or Mn of 50,000 Da to less than 100,000 Da) molecular weight polymers.
  • Mw weight average molecular weight
  • Mn number average molecular weight
  • acrylic polymers may be synthesized via radical emulsion polymerization.
  • the acid- or anhydride-functional acrylic polymer or the at least partially neutralized acid- or anhydride functional acrylic polymer is an organic-solution polymerized acrylic polymer.
  • Organic-solution polymerized means that the acrylic polymer is formed by radical polymerizing an ethylenically unsaturated monomer component in an organic solvent, which typically forms a continuous phase of the reaction mixture. Suitable organic solvents include ketones, glycol ethers, esters, alcohols, aromatics, or combinations thereof.
  • solvents examples include cyclohexanone, ethylcarbitol, butyl carbitol, butylcellosolve, butanol, amyl alcohol, methyl isobutyl ketone, methyl isoamyl ketone, methyl amyl ketone, xylene, AROMATIC 150 (Chemical Abstract Services (CAS) number: 64742-94-5) , AROMATIC 100 10 ⁇ ⁇ (CAS number: 64742-95-6), hexylcellosolve, toluene, propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, dibasic ester, diisobutyl ketone, and mixtures thereof.
  • a catalyst or polymerization initiator is ordinarily used in the polymerization of acrylic polymers, in the usual amounts.
  • This can be any suitable free radical initiator.
  • azoalkanes, peroxides, tertiary butyl perbenzoate, tertiary butyl peroxypivalate, and tertiary butyl peroxyisobutyrate are suitable.
  • the acrylic polymer is a copolymer of two or more prepolymers (preferably two or more acrylic prepolymers).
  • a “prepolymer” is a polymeric starting material used to make the final acrylic polymer. Such prepolymers are formed from an ethylenically unsaturated monomer component.
  • the ethylenically unsaturated monomer component of the acrylic polymer and/or prepolymers include acid-functional monomers, optionally hydroxyl-functional monomers, and optionally other monomers referred to herein as secondary monomers (the term “secondary does not necessarily correlate to the amount of such monomers).
  • a “secondary monomer” is a monomer that does not include an acid, anhydride, or hydroxyl functionality or other active hydrogen group, and includes monomers such as, for example, alkyl (meth)acrylates, cycloalkyl (meth)acrylates, aryl (meth)acrylates, styrene, and the like.
  • Exemplary secondary monomers include alkyl, cycloalkyl, or aromatic (meth)acrylate monomers.
  • at least one, or each (i.e., all), of the two or more prepolymers is an at least partially neutralized acid- or anhydride-functional acrylic prepolymer.
  • at least one, or each (i.e., all), of the two or more prepolymers is an organic-solution polymerized acrylic prepolymer. By this it is meant that the prepolymer is polymerized in an organic solvent as described herein.
  • the acrylic polymer is hydroxyl-functional (i.e., includes one or more hydroxyl groups), wherein such group may be used for crosslinking with the phenolic crosslinker.
  • at least one of the acrylic prepolymers, and preferably each of the two or more acrylic prepolymers if used to form the acrylic polymer is a hydroxyl-functional prepolymer.
  • the acrylic polymer, and/or at least one, preferably each, acrylic prepolymer if used to form the acrylic polymer has a calculated hydroxyl number of less than 120, less than 60, or less than 30 mg KOH per gram resin.
  • the acrylic polymer, and/or at least one, preferably each, acrylic prepolymer if used to form the acrylic 11 ⁇ ⁇ polymer has a calculated hydroxyl number of at least 5, at least 15, or at least 28 mg, KOH per gram resin.
  • the acrylic polymer and/or prepolymers, if used to form the acrylic polymer preferably have an acid number. Acid numbers may be calculated or determined experimentally (see Test Methods) from the acid-functional monomers of the ethylenically unsaturated monomer component. There are often differences between calculated and experimentally determined acid numbers.
  • acid-functional monomers are those that will react with an organic base or inorganic base, such as KOH, under ambient conditions, and typically include carboxylic acid-functional monomers, as well as others that will also react with KOH under ambient conditions, such as certain phosphorus-containing (e.g., phosphoric acid-functional or phosphonic acid-functional) monomers and certain sulfur-containing (e.g., sulfonic acid-functional) monomers may be included in the calculation of acid number.
  • organic base or inorganic base such as KOH
  • carboxylic acid-functional monomers as well as others that will also react with KOH under ambient conditions, such as certain phosphorus-containing (e.g., phosphoric acid-functional or phosphonic acid-functional) monomers and certain sulfur-containing (e.g., sulfonic acid-functional) monomers may be included in the calculation of acid number.
  • Exemplary structures of acid-functional monomers are as follows: ⁇ If the functional monomer(s) other than carboxylic acid-functional monomers (e.g., phosphorus- or sulfur-containing acid- functional monomers), such non-carboxylic acid-functional monomers are preferably present in an amount of less than 50 wt-%, less than 25 wt-%, less than 10 wt-%, less than 5 wt-%, less than 2 wt-%, or less than 1 wt-%, if any, based on the total weight of the acid-functional monomers in the ethylenically unsaturated monomer component. Preferably, however, only carboxylic acid- functional monomers are included in the calculation of acid number.
  • the functional monomer(s) other than carboxylic acid-functional monomers e.g., phosphorus- or sulfur-containing acid- functional monomers
  • such non-carboxylic acid-functional monomers are preferably present in an amount of less than 50 wt-%,
  • the acid numbers herein are calculated acid numbers.
  • the acrylic polymer has a calculated acid number of less than 60 mg KOH per gram resin.
  • all the acrylic prepolymers, if used to form the acrylic polymer have an acid number within ⁇ 10 mg KOH per gram resin.
  • at least one, preferably each, of the two or more acrylic prepolymers, if used to form the acrylic polymer has a calculated acid number.
  • Suitable acrylic polymers, and/or at least one, 12 ⁇ ⁇ preferably each, acrylic prepolymer if used to form the acrylic polymer, for use in an aqueous food or beverage container coating composition have a calculated acid number of less than 50 mg, less than 40 mg, or less than 35 mg, KOH per gram resin.
  • the acrylic polymer, and/or at least one, preferably each, acrylic prepolymer if used to form the acrylic polymer has a calculated acid number of at least 8 mg, at least 10 mg, at least 20 mg, at least 30 mg, or at least 32 mg, KOH per gram resin.
  • the calculated acid values of this paragraph are achieved via the amount of carboxylic-acid monomer used (an anhydride-functional monomer is considered as a carboxylic-acid monomer as an anhydride group yields two carboxylic groups), while not factoring as acid monomer any non-carboxylic acid monomers that may be present, if any. That is, the calculated acid number only factors acid monomers including a carboxylic acid group, an anhydride group (which yields two carboxylic groups), or a salt group thereof.
  • the acrylic polymers of the present disclosure are at least partially neutralized, and therefore have a “degree of neutralization.”
  • This at least partial neutralization of the acrylic polymer contributes to the stability and/or viscosity of the aqueous dispersion of the acrylic polymer.
  • the solubility of the polymer may increase at a constant acid number. Increase in the solubility of the polymer at a constant acid number may result in an increased viscosity.
  • the degree of neutralization is calculated as the amount of base (e.g., N,N- dimethylethanolamine) added to the solution containing the polymer and/or prepolymer divided by the calculated acid number of said polymer and/or prepolymer.
  • the degree of neutralization can be greater than 100%.
  • a polymer that has a calculated acid number of 8 mg KOH per gram resin may have an experimentally determined acid number of 18 mg KOH per gram resin, meaning there are other sources of acid in addition to the acid-functionalized polymer in the solution that are also being neutralized.
  • the addition of more than 8 mg of a base would result in a degree of neutralization greater than 100%, even though not all of the acid-functional monomer groups may or may not be neutralized.
  • the acrylic polymers of the present disclosure are at least partially neutralized with a base, preferably a fugitive base (also known as a volatile base or volatile fugitive base).
  • Nonlimiting examples of volatile fugitive bases include various amines such as ammonium, 13 ⁇ ⁇ ethylamine, dimethylethanolamine, triethanolamine, triethylamine, dimethylamine, and combinations thereof.
  • the acrylic polymer has a degree of neutralization of no more than 200%, no more than 150%, no more than 100%, no more than 80%, or no more than 60%, based on an acid number of at least 8 mg KOH per gram resin.
  • the acrylic polymer has a degree of neutralization of no more than 150%, no more than 100%, no more than 80%, or no more than 60%, based on an acid number of at least 15 mg KOH per gram resin.
  • the acrylic polymer has a degree of neutralization of no more than 100%, no more than 80%, or no more than 60%, based on an acid number of at least 20 mg KOH per gram resin. In certain embodiments, the acrylic polymer has a degree of neutralization of no more than 80%, or no more than 60%, based on an acid number of at least 32 mg KOH per gram resin. In certain embodiments, the acrylic polymer has a degree of neutralization of no more than 100%, no more than 80%, or no more than 60%, based on an acid number of at least 40 mg KOH per gram resin.
  • the acid number, hydroxyl number, and degree of neutralization are preferably balanced to provide a stable dispersion of the mixture of phenolic crosslinker and acrylic polymer in water. It is contemplated that through careful monomer selection, in some embodiments, no neutralization is necessary to form a stable dispersion of the mixture of the phenolic crosslinker and acrylic polymer in water.
  • the acrylic polymer is prepared from two or more at least partially neutralized acid- or anhydride-functional organic-solution polymerized acrylic prepolymers, wherein: at least one acrylic prepolymer is hydroxyl-functional; each of the two or more acrylic prepolymers preferably has a calculated acid number of less than 60 mg KOH per gram resin; and each of the two or more acrylic prepolymers is self-dispersible in water. 14 ⁇ ⁇
  • the acrylic polymer is a single-stage polymer, that is, the acrylic polymer has a single glass transition temperature (Tg).
  • the glass transition temperature (Tg) can be measured, for example, using differential scanning calorimetry (DSC) or calculated using the Fox Equation.
  • a cured coating of the coating composition containing the acrylic polymer has a single Tg, measured, for example, using DSC.
  • the single Tg of the cured coating is greater than 50 °C (which is the temperature of the hot room for food cans).
  • the acrylic polymer has a calculated (aggregate of all monomers) Tg of at least 35 °C, at least 40 °C, at least 45 °C, or at least 50 °C (and in certain embodiments up to 95 °C).
  • At least one, preferably each, of the two or more acrylic prepolymers, if used to prepare the acrylic polymer, has a calculated (aggregate of all monomers) Tg of at least 35 °C, at least 40 °C, at least 45 °C, or at least 50 °C (and in certain embodiments up to 95 °C).
  • a “calculated Tg” is used interchangeably with “Fox Tg” and “calculated Fox Tg.”
  • the Tg of a particular polymer or prepolymer can be estimated (i.e., calculated) using the Fox equation.
  • the theoretical Tg may be calculated using the Fox equation as follows: ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ wherein: Tga and Tgb are the respective glass transition temperatures in Kelvin of homopolymers made from monomers “a” and “b”; and W a and W b are the respective weight fractions of polymers “a” and “b”.
  • Tga and Tgb are the respective glass transition temperatures in Kelvin of homopolymers made from monomers “a” and “b”
  • W a and W b are the respective weight fractions of polymers “a” and “b”.
  • the calculation is based on all of the monomers that are reacted together to form a polymer or prepolymer, and not upon merely a portion of such monomers.
  • the Fox equation cannot be used to calculate the Tg of a polymer crosslinked with a crosslinking agent or a composition containing a polymer and a crosslinking agent.
  • the value of Tg of the monomers used to estimate the polymer or prepolymer Tg are based on literature values. Typically, there is some variation of the Tg values of the homopolymers of monomers listed in such literature. The difference arises from the test method used to measure the 15 ⁇ ⁇ Tg. The differences can also arise from influence of comonomers polymerized together.
  • the values used for the homopolymer Tg of certain monomers, particularly monomers used in the examples are listed herein (e.g., in the Materials Table in the Examples Section).
  • the method of determining the Tg of a homopolymer can be determined using the differential scanning calorimetry (DSC) procedure described in the Test Methods, particularly if the literature values are significantly different from one another (e.g., the literature values vary by at least 15°C). If the literature values vary by less than 15°C, then the lower literature value is used.
  • DSC differential scanning calorimetry
  • the acrylic polymer has a number average molecular weight (Mn) of at least 6,000 Da, at least 8,000 Da, at least 10,000 Da, or at least 12,000 Da, as determined using gel permeation chromatography (GPC) and a series of polystyrene standards with different molecular weights.
  • Mn number average molecular weight
  • the acrylic polymer has a Mn of up to 35,000 Da, up to 30,000 Da, up to 28,000 Da, or up to 25,000 Da, as determined using GPC and a series of polystyrene standards with different molecular weights.
  • At least one, preferably each, of the two or more acrylic prepolymers, if used to prepare the acrylic polymer has a Mn of at least 6,000 Da, at least 8,000 Da, at least 10,000 Da, or at least 12,000 Da, as determined using GPC and a series of polystyrene standards with different molecular weights. In certain embodiments, at least one, preferably each, of the two or more acrylic prepolymers, if used to prepare the acrylic polymer, has a Mn of up to 35,000 Da, up to 30,000 Da, up to 28,000 Da, or up to 25,000 Da, as determined using GPC and a series of polystyrene standards with different molecular weights.
  • the one or more acid-functional monomers used to form the acrylic polymer and/or acrylic prepolymers of the present disclosure include acrylic acid, methacrylic acid, crotonic acid, unsaturated dicarboxylic acid or anhydride (e.g., maleic acid, fumaric acid, itaconic acid, and maleic anhydride), phosphorus-containing monomers, sulfur-containing monomers, monoalkyl maleate or anhydride, or combinations thereof.
  • the one or more acid-functional monomers include (meth)acrylic acid (i.e., acrylic acid and methacrylic acid).
  • phosphorus-containing acid-functional monomers include, for example, bis(2- methacryloxyethyl) phosphate, ethylene glycol methacrylate phosphate, phosphoric acid (meth)acrylate, phosphonic acid (meth)acrylate.
  • sulfur-containing acid-functional monomers include, for example, 2-propene-1-sulfonic acid, 2-acrylamido-2-methylpropane 16 ⁇ ⁇ sulfonic acid, 2-sulfonyl-methacrylate, 2-methyl-2-propene-1-sulfonic acid sodium salt, 2-sulfonyl methacrylate potassium salt.
  • the acrylic polymers and/or acrylic prepolymers of the present disclosure include no more than 8 wt-%, no more than 7 wt-%, no more than 6 wt-%, or no more than 5 wt-%, interpolymerized acid-functional monomers, based on the total weight of the monomers.
  • the acrylic polymers and/or prepolymers of the present disclosure include an amount of acrylic acid and/or methacrylic acid pursuant to the above amounts.
  • one or more hydroxyl-functional monomers, particularly hydroxyl- functional (meth)acrylate monomers may be used to form the acrylic polymer and/or acrylic prepolymers of the present disclosure.
  • the acrylic polymers and/or acrylic prepolymers of the present disclosure include polyester-acrylic copolymers, polyether-acrylic copolymers (i.e., epoxy-acrylic copolymers), and/or polyurethane-acrylic copolymers.
  • the acrylic polymers and/or acrylic prepolymers of the present disclosure comprise, and preferably include, interpolymerized (meth)acrylic acid monomers, (meth)acrylate monomers, or combinations thereof.
  • an at least partially neutralized acid- or anhydride-functional organic-solution polymerized acrylic crosslinked polymer includes interpolymerized monomers including (meth)acrylic acid monomers (and optionally one or more hydroxyl-functional monomers, particularly hydroxyl-functional (meth)acrylate monomers such as hydroxypropyl (meth)acrylate monomers, and typically also one or more secondary monomers such as one or more alkyl, cycloalkyl, or aromatic (meth)acrylate monomers); wherein the acrylic polymer is hydroxyl-functional, has a calculated acid number of less than 60 mg KOH per gram resin, is self-dispersible in water, and is crosslinked with at least 5 wt-% resole phenolic crosslinker, based on total resin solids.
  • the coating composition may include a mixture of one or more resole resins that are not etherified and one or more etherified resole resins (preferably butylated resole resin).
  • the total amount of the one or more non-etherified resole resins is 20 wt-% or less, 10 wt-% or less, or 5 wt-% or less of the total amount of resole resin in the coating composition.
  • the amount of phenolic crosslinker used will depend, for example, on the type of phenolic crosslinker, the time and temperature of the bake, and the molecular weight of the acrylic polymer.
  • the amount of phenolic crosslinker (preferably, resole phenolic crosslinker) is preferably present in an aqueous coating composition in an amount of at least 1 wt- %, at least 2 wt-%, at least 5 wt-%, at least 10 wt-%, at least 15 wt-%, or at least 20 wt-%, based on total resin solids of the coating composition.
  • the amount of phenolic crosslinker (preferably, resole phenolic crosslinker) is preferably present in an aqueous coating composition in an amount of up to 50 wt-%, up to 40 wt-%, up to 30 wt-%, up to 20 wt-%, or up to 10 wt-%, based on total resin solids of the coating composition.
  • suitable optional ingredients include catalysts, dyes, pigments (e.g., TiO 2 , carbon black), anti-staining agents (e.g., ZnO), toners, extenders, fillers, lubricants, anticorrosion agents, flow-control agents, thixotropic agents, dispersing agents (e.g., wax dispersants), antioxidants, adhesion promoters, light stabilizers, curing agents, surfactants, or mixtures thereof.
  • a particularly useful optional ingredient is a pigment, like titanium dioxide (TiO 2 ).
  • a pigment is optionally present in the coating composition in an amount of up to 50 wt-%, based on the total weight of the nonvolatile material.
  • preferred coating compositions of the present disclosure include TiO 2 and optionally carbon black.
  • coating compositions of the present disclosure include a surfactant, which may be a polymeric or small molecule surfactant. In certain embodiments, if a composition includes any surfactant, it includes at least 0.01 wt-%, at least 0.1 wt-%, at least 0.5 wt-%, or at least 1 wt-%, surfactant (polymeric or small molecule surfactant), based on the total weight of total 24 ⁇ ⁇ resin solids.
  • Suitable surfactants may be polymeric or small molecule surfactants (i.e., low molecular weight surfactants).
  • the surfactant may be a defoamer, e.g., silicon-based surfactants such as those available under the trade designation AGITAN 731 from Münzing Chemie in Clover, SC.
  • the surfactant may be a leveling agent, e.g., acrylic-based surfactants such as those available under the trade designation MODAFLOW from Allnex in Kalamazo, MI.
  • an external surfactant either a low molecular weight surfactant or polymeric surfactant
  • a hydrophobic acrylic to form a dispersion via a double layer morphology or a graft copolymer approach (e.g., an acrylic polymeric surfactant grafted to a hydrophobic acrylic polymer).
  • a low molecular weight surfactant can result in poor water resistance and corrosion resistance in a cured coating film.
  • a polymeric surfactant usually contains 40-60% of unsaturated carboxylic acid monomer. When it is partially neutralized with an appropriate organic base, the acrylic surfactant stabilizes a hydrophobic polymer and forms an acrylic dispersion.
  • This type of dispersion has an uneven distribution of hydrophilic acidic groups in the dispersion system.
  • the resultant cured film therefore, can be water sensitive due to the unreacted acidic group.
  • This type of surfactant therefore, has some drawbacks.
  • a surfactant-free acrylic dispersion is prepared from a high acid or low acid content polymer resin, where the acid groups are randomly distributed on the backbone of the polymer, in the presence of an appropriate organic base.
  • This approach improves water resistance and corrosion resistance; however, it is difficult to make a stable acrylic dispersion containing a phenolic resin.
  • surfactant-free acrylic dispersions made using approach two generally do not include a phenolic resin.
  • a surfactant-free acrylic resin not only stabilizes itself but also stabilizes a phenolic resin by encapsulating it and forming a uniform coating composition.
  • the stability of this dispersion depends on the hydrophilic–lipophilic balance of the acid- or anhydride- functional acrylic polymer. For example, an acid- or anhydride-functional acrylic polymer that is too lipophilic will result in an aqueous coating composition that has two distinct phases, not a dispersion.
  • an acid- or anhydride-functional acrylic polymer that is too hydrophilic will result in an aqueous coating composition that is a highly viscous dispersion or, in some cases, even homogeneous solution of one phase.
  • Factors affecting the hydrophilicity and lipophilicity of polymers include the acid number, the hydroxyl number, the degree of neutralization, and the polarity of the monomers. Generally, the greater number of acid groups (higher acid number) and the greater the number of hydroxy groups (higher hydroxyl number), the greater degree of hydrophilicity.
  • Nonpolar monomers or monomers that have low polarity generally increase the lipophilicity of the polymer.
  • the approach of the present disclosure strikes a balance between hydrophilicity and lipophilicity of an acid- or anhydride-functional acrylic polymer to allow for surfactant-free aqueous coating compositions containing phenolic resin.
  • This approach also provides a favorable total solids-viscosity relationship with low acid content and results in a high amount of total solids at a viscosity suitable for spraying to form coatings of adequate film thickness.
  • an aqueous food or beverage container coating composition (preferably, an aqueous food container coating composition) is provided that includes: at least 50 wt-%, based on total resin solids, of an at least partially neutralized acid- or anhydride-functional organic-solution polymerized acrylic polymer; a phenolic crosslinker; and an aqueous liquid carrier; wherein the coating composition is storage stable for at least 2 months, at ambient temperature, not in direct sunlight, without any phase separation as determined by the unaided human eye.
  • the acrylic polymer is hydroxyl-functional, has a calculated acid number of less than 60 mg KOH per gram resin, and is self-dispersible in water.
  • an aqueous food or beverage container coating composition (preferably, an aqueous food container coating composition) is provided that includes: at least 50 26 ⁇ ⁇ wt-%, based on total resin solids, of an at least partially neutralized acid- or anhydride-functional organic-solution polymerized acrylic polymer; at least 5 wt-% phenolic crosslinker, based on total resin solids; and an aqueous liquid carrier.
  • the acrylic polymer is hydroxyl- functional, has a calculated acid number of less than 60 mg KOH per gram resin, and is self- dispersible in water.
  • an aqueous food or beverage container coating composition (preferably, an aqueous food container coating composition) is provided that includes: at least 50 wt-%, based on total resin solids, of an acrylic polymer prepared from two or more at least partially neutralized acid- or anhydride-functional organic-solution polymerized acrylic prepolymers; at least 5 wt-% of a phenolic crosslinker, based on total resin solids; and an aqueous liquid carrier.
  • At least one acrylic prepolymer is hydroxyl-functional, each of the two or more acrylic prepolymers has a calculated acid number of less than 60 mg KOH per gram resin, and each of the two or more prepolymers is self-dispersible in water.
  • an aqueous food or beverage container coating composition (preferably, an aqueous food container coating composition) is provided that includes: at least 50 wt-%, based on total resin solids, of an at least partially neutralized acid- or anhydride-functional organic-solution polymerized acrylic polymer; at least 20 wt-% of a phenolic crosslinker, based on total resin solids; and an aqueous liquid carrier; wherein the coating composition includes 20 wt-% to 40 wt-% of total solids, based on the total weight of the composition, and is storage stable for at least 2 months at ambient temperature without any phase separation as determined by the unaided human eye.
  • the acrylic polymer is hydroxyl-functional, has a calculated acid number of less than 60 mg KOH per gram resin, and is self-dispersible in water. 27 ⁇ ⁇
  • the coating compositions of the present disclosure include an aqueous liquid carrier (e.g., water and/or an organic solvent).
  • the coating compositions of the present disclosure include water and may further include one or more optional organic solvents. Such compositions are referred to herein as aqueous coating compositions.
  • the coating composition includes at least 40 wt-%, or at least 50 wt- %, water, based on the total weight of the coating composition.
  • the coating composition includes no more than 60 wt-%, or no more than 55 wt-%, water, based on the total weight of the coating composition. In some embodiments, the coating composition includes at least 0.1 wt-%, at least 0.5 wt-%, at least 1 wt-%, or at least 5 wt-%, of one or more organic solvents, based on the total weight of the coating composition. In some embodiments, the coating composition includes no more than 22 wt- %, or no more than 20 wt-%, of one or more organic solvents, based on the total weight of the coating composition.
  • the aqueous liquid carrier includes at least 50 wt-%, at least 60 wt- %, at least 70 wt-%, or at least 80 wt-%, of water, based on the total weight of the liquid carrier. In some embodiments, the aqueous liquid carrier includes 100 wt-% or less, 95 wt-% or less, or 90 wt- % or less, of water, based on the total weight of the liquid carrier. In some embodiments, the liquid carrier is free or substantially free of organic solvent. In some embodiments, the aqueous liquid carrier includes at least 50 wt-%, based on the total weight of the liquid carrier, of one or more organic solvents.
  • the organic solvent includes ethylene glycol monobutyl ether, ethylene glycol monohexyl ether, diethylene glycol monoethyl ether, isopropanol, butanol, or combinations thereof.
  • the amount of liquid carrier included in a coating composition of the present disclosure is limited by the desired, or necessary, rheological properties of the composition. Usually, a sufficient amount of carrier is included in the coating composition to provide a composition that can be processed easily and that can be applied to a metal substrate easily and uniformly using a particular application process, and that is sufficiently removed from the coating composition during curing within the desired cure time.
  • a coating composition includes at least 62 wt-%, at least 64 wt-%, at least 66 wt-%, at least 68 wt-%, at least 70 wt-%, at least 72 wt-%, at least 74 wt-%, at least 76 wt- 28 ⁇ ⁇ %, at least 78 wt-%, at least 80 wt-%, at least 82 wt-%, or at least 84 wt-% liquid carrier.
  • a coating composition will typically include up to 86 wt-%, up to 84 wt-%, up to 82 wt-%, up to 80 wt-%, up to 78 wt-%, up to 76 wt-%, up to 74 wt-%, up to 72 wt-%, up to 70 wt-%, up to 68 wt-%, up to 66 wt-%, up to 64 wt-%, up to 62 wt-%, or up to 60 wt-% liquid carrier. These weight percentages are based upon the total weight of the coating composition. The total solids may constitute the remainder of the weight of the aqueous composition.
  • a coating composition includes up to 40 wt-%, up to 38 wt-%, up to 36 wt-%, up to 34 wt-%, up to 32 wt-%, up to 30 wt-%, up to 28 wt-%, up to 26 wt-%, up to 24 wt-%, up to 22 wt-%, up to 20 wt-%, up to 18 wt-%, or up to 16 wt-% total solids.
  • a coating composition will typically include at least 14 wt-%, at least 16 wt-%, at least 18 wt-%, at least 20 wt-%, at least 22 wt-%, at least 24 wt-%, at least 26 wt-%, at least 28 wt-%, at least 30 wt-%, at least 32 wt-%, at least 34 wt-%, at least 36 wt-%, or at least 38 wt-% total solids.
  • the coating composition includes 16 wt-% to 40 wt-% or 20 wt-% to 40 wt-% total solids.
  • the coating composition includes 24 wt-% to 34 wt-%, 14 wt-% to 22 wt-%, or 30 wt-% to 38 wt-% total solids. These weight percentages are based upon the total weight of the coating composition.
  • the aqueous liquid carrier may constitute the remainder of the weight of the aqueous composition.
  • an aqueous coating composition includes solids in an amount of at least 5 wt-%, at least 10 wt-%, or at least 15 wt-%, based on total weight of the aqueous composition.
  • a coating composition has a viscosity of at least 50 centipoise (cps). In certain embodiments, a coating composition has a viscosity of up to 300 cps, or up to 200 cps. Viscosity of the coating composition can be measured using a viscometer (e.g., a Brookfield viscometer) at ambient temperature.
  • a viscometer e.g., a Brookfield viscometer
  • the coating compositions described herein have a pH of at least 7.5, or at least 8.0. ⁇
  • the coating compositions of the present disclosure are storage stable under normal storage conditions (e.g., ambient temperature and not stored in direct sunlight, such as when stored in a cabinet) for at least 2 months, preferably at least 3 months, more preferably at least 4 months, or most preferably at least 6 months.
  • storage stable 29 ⁇ ⁇ means that the compositions do not phase separate (e.g., separate into two or more layers) as determined by the unaided human eye.
  • a cured coating formed from a coating composition of the present disclosure has a Tg of at least 50°C.
  • the coating compositions are “PVC-free.” That is, the aqueous coating composition preferably contains, if any, less than 2 wt-% of vinyl chloride materials and other halogenated vinyl materials, more preferably less than 0.5 wt-% of vinyl chloride materials and other halogenated vinyl materials, and even more preferably less than 1 ppm of vinyl chloride materials and other halogenated vinyl materials, if any.
  • a coated metal substrate includes a metal substrate having a cured adherent coating disposed on at least a portion of a surface thereof, wherein the coating is formed from an aqueous food container coating composition including: at least 50 wt-%, based on total resin solids, of an at least partially neutralized acid- or anhydride-functional organic-solution polymerized acrylic polymer; at least 20 wt-% of crosslinker including one or more phenolic crosslinkers (preferably, resole phenolic crosslinkers), based on total resin solids; and an aqueous liquid carrier.
  • an aqueous food container coating composition including: at least 50 wt-%, based on total resin solids, of an at least partially neutralized acid- or anhydride-functional organic-solution polymerized acrylic polymer; at least 20 wt-% of crosslinker including one or more phenolic crosslinkers (preferably, resole phenolic crosslinkers), based on total resin solids; and an aqueous liquid carrier.
  • the ethylenically unsaturated monomer component includes, for example, (meth)acrylic acid monomers, optionally hydroxyl-functional monomers, particularly hydroxyl-functional (meth)acrylate monomers such as hydroxypropyl (meth)acrylate monomers, and optionally secondary monomers (such as a (C1-C12) (meth)acrylate monomer and styrene as described herein).
  • monomers and organic solvents are further described herein, as are other preferred characteristics (e.g., hydroxyl number, acid number, molecular weight) of the acrylic polymer, which is preferably halogen-free, bisphenol A, bisphenol F free, bisphenol S free, or combinations thereof.
  • the acid- or anhydride- functional acrylic polymer is styrene free.
  • the method also includes at least partially neutralizing the acid- or anhydride- functional acrylic polymer with a base, more preferably a fugitive base.
  • a base more preferably a fugitive base.
  • fugitive bases used for neutralization include ammonia, ammonium hydroxide, an amine (e.g., a primary, secondary, or 35 ⁇ ⁇ tertiary amine, with dimethylethanolamine being an example of a preferred amine), or a combination thereof.
  • the degree of neutralization is further described herein.
  • the method includes combining the mixture of polymer and crosslinker with water to form an aqueous coating composition that includes (i) at least 50 wt-%, based on total resin solids, of the acrylic polymer and (ii) at least 5 wt-%, based on total resin solids, of the phenolic crosslinker.
  • combining the mixture with water includes adding water to the mixture. This water addition can occur over a period of time, for example, over a period of one hour.
  • the aqueous coating composition includes at least 10 wt-%, at least 15 wt-%, or at least 20 wt-%, of the resole phenolic crosslinker, based on total resin solids.
  • Another method of the present disclosure includes a method of coating a food or beverage container.
  • the method includes: providing an aqueous food or beverage container coating composition as described herein; causing the coating composition to be applied to at least a portion of a metal substrate (e.g., a steel or aluminum substrate) prior to or after forming the metal substrate into a food or beverage container or portion thereof; and thermally curing the coating composition to form a cured coating.
  • a metal substrate e.g., a steel or aluminum substrate
  • the coating composition is an inside spray beverage can coating composition
  • the coating composition is an inside spray food can coating composition (e.g., for an aluminum D&I food can).
  • the coating composition is applied to a food- or beverage-contact surface of the metal substrate (e.g., an interior side of a food or beverage can or a surface that will become an interior side of a food or beverage can).
  • methods of the present disclosure can involve applying the coating composition to a flat substrate, and then forming the flat metal substrate into at least a portion of a container (e.g., food or beverage can) after thermally curing the coating composition.
  • Embodiment 50 is the coating composition of any of the preceding embodiments, wherein the acrylic polymer comprises interpolymerized acid-functional monomers and optionally hydroxyl-functional monomers.
  • Embodiment 51 is the coating composition of embodiment 50, wherein the acid-functional monomers comprise (meth)acrylic acid, crotonic acid, unsaturated dicarboxylic acid or anhydride 46 ⁇ ⁇ (e.g., maleic acid, fumaric acid, itaconic acid, and maleic anhydride), phosphoric acid (meth)acrylate, phosphonic acid (meth)acrylate, monoalkyl maleate or anhydride, or combinations thereof.
  • the acid-functional monomers comprise (meth)acrylic acid, crotonic acid, unsaturated dicarboxylic acid or anhydride 46 ⁇ ⁇ (e.g., maleic acid, fumaric acid, itaconic acid, and maleic anhydride), phosphoric acid (meth)acrylate, phosphonic acid (meth)acryl
  • Embodiment 58 is the coating composition of embodiment 57, wherein the secondary monomers comprise methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, cyclohexyl (meth)acrylate, benzyl (meth)acrylate, or combinations thereof.
  • Embodiment 59 is the coating composition of any of embodiments 50 through 58, wherein the acrylic polymer comprises at least 1.0 wt-%, at least 1.5 wt-%, at least 2.0 wt-%, at least 2.5 wt-%, 47 ⁇ ⁇ at least 3.0 wt-%, at least 3.5 wt-%, or at least 4.0 wt-% interpolymerized acid-functional monomers, based on the total weight of the monomers used in the polymerization reaction.
  • Embodiment 61 is the coating composition of any of embodiments 50 through 60, wherein the acrylic polymer comprises at least 1.0 wt-%, at least 1.5 wt-%, at least 2.0 wt-%, at least 2.5 wt-%, at least 3.0 wt-%, at least 3.5 wt-%, at least 4.0 wt-%, at least 4.5 wt-%, at least 5.0 wt-%, or at least 5.5 wt-% interpolymerized hydroxyl-functional monomers, based on the total weight of the monomers used in the polymerization reaction.
  • Embodiment 62 is the coating composition of any of embodiments 50 through 61, wherein the acrylic polymer comprises no more than 35 wt-%, no more than 30 wt-%, no more than 25 wt- %, no more than 20 wt-%, no more than 15 wt-%, no more than 10 wt-%, or no more than 8 wt-% interpolymerized hydroxyl-functional monomers, based on the total weight of the monomers, used in the polymerization reaction.
  • Embodiment 63 is the coating composition of any of embodiments 55 through 62, wherein the acrylic polymer comprises at least 50 wt-%, at least 55 wt-%, at least 60 wt-%, at least 65 wt-%, at least 70 wt-%, at least 75 wt-%, at least 80 wt-%, or at least 85 wt-% interpolymerized secondary monomers, based on the total weight of the monomers used in the polymerization reaction.
  • Embodiment 64 is the coating composition of any of embodiments 55 through 63, wherein the acrylic polymer comprises no more than 98 wt-%, no more than 96 wt-%, or no more than 90 wt-% interpolymerized secondary monomers, based on the total weight of the monomers, used in the polymerization reaction.
  • Embodiment 65 is the coating composition of any one of embodiments 50 through 64, wherein the acrylic polymer comprises no more than 40 wt-%, no more than 30 wt-%, no more than 20 wt-%, or no more than 10 wt-% interpolymerized styrene monomers based on the total weight of the monomers used in the polymerization reaction.
  • Embodiment 66 is the coating composition of embodiment 65, wherein the acrylic polymer is styrene-free. 48 ⁇ ⁇ Embodiment 67 is the coating composition of any one of embodiments 50 through 66, wherein the acrylic polymer does not include interpolymerized vinyl chloride monomers.
  • Embodiment 68 is the coating composition of any preceding embodiments, wherein the acrylic polymer is halogen-free.
  • Embodiment 69 is the coating composition of any one of embodiments 50 through 68, wherein the acrylic polymer consists of interpolymerized (meth)acrylic acid, (meth)acrylate monomers, or combinations thereof.
  • Embodiment 70 is the coating composition of any of the preceding embodiments, wherein the acrylic polymer is in the form of particles having a particle size distribution having one, two, or all of the following: a D10 of less than 0.15 micrometer, a D50 of less than 0.25 micrometer, a D90 of less than 0.50 micrometer.
  • Embodiment 71 is the coating composition of any of the preceding embodiments, wherein the acrylic polymer is in the form of particles having a particle size distribution having one, two, or all of the following: a D10 of at least 0.07 micrometer, a D50 of at least 0.10 micrometer, a D90 of at least 0.12 micrometer.
  • Embodiment 72 is the coating composition of any of the preceding embodiments, which is substantially free of each of bisphenol A, bisphenol F, and bisphenol S.
  • Embodiment 73 is the coating composition of any of the preceding embodiments, which is substantially free of all bisphenol compounds not including tetramethyl bisphenol F (TMBPF).
  • Embodiment 74 is the coating composition of any of the preceding embodiments, which forms a cured coating that includes less than 50 ppm, less than 25 ppm, less than 10 ppm, or less than 1 ppm, extractables, if any, when tested pursuant to the Global Extraction Test in the Test Methods.
  • Embodiment 75 is the coating composition of any of the preceding embodiments, wherein when applied on a tin plate panel having a thickness of 0.0208 mm in an amount sufficient to achieve a dry film weight of 4-5 mg/in 2 , after exposure to a temperature of 425°F (218°C) for 3.5 minutes, provides a cured coating having one or more of the following properties: an adhesion rating of at least 4B (i.e., 4B or 5B), when tested pursuant to the Adhesion Test in the Test Methods; a double rub rating of at least 30 or at least 50 when tested pursuant to the Solvent Resistance Test in the Test Methods (ASTM D 5402-93for MEK rubs); or displaying no crazing when tested pursuant to the Reverse Impact Test (ASTM D2794-93) in the Test Methods.
  • an adhesion rating of at least 4B i.e., 4B or 5B
  • a double rub rating of at least 30 or at least 50 when tested pursuant to the Solvent Resistance
  • Embodiment 76 is the coating composition of any of the preceding embodiments, wherein a cured coating has a single glass transition temperature, measured using DSC, of greater than 50°C (which is the temperature of the hot room for food cans).
  • Embodiment 77 is the coating composition of any of the preceding embodiments which is an interior (food or beverage) container coating composition.
  • Embodiment 78 is the coating composition of any of the preceding embodiments which is a food container coating composition.
  • Embodiment 79 is the coating composition of embodiment 78 which is an inside spray two- piece food D&I can coating composition.
  • Embodiment 84 is the polymer of any one of embodiments 80 through 83 further comprising interpolymerized monomers comprising styrene.
  • Embodiment 85 is the polymer of any one of embodiments 80 through 83, which is styrene- free.
  • Embodiment 86 is the polymer of any one of embodiments 80 through 85, which is halogen-free. 50 ⁇ ⁇
  • Embodiment 87 is the polymer of any one of embodiments 80 through 86, which is crosslinked with at least 10 wt-%, at least 15 wt-%, or at least 20 wt-% of the resole phenolic crosslinker, based on total resin solids.
  • Embodiment 88 is the polymer of any one of embodiments 80 through 87, which is crosslinked with up to 50 wt-%, up to 40 wt-%, up to 30 wt-%, up to 20 wt-%, or up to 10 wt-% of the resole phenolic crosslinker, based on total resin solids.
  • Embodiment 89 is the polymer of any one of embodiments 80 through 88, wherein the acrylic polymer (prior to cure) has a single glass transition temperature, measured using DSC.
  • Embodiment 90 is the polymer of any one of embodiments 80 through 89, wherein the acrylic polymer has a calculated (aggregate of all monomers) glass transition temperature of at least 35°C.
  • Embodiment 91 is the polymer of embodiments 90, wherein the acrylic polymer has a calculated (aggregate of all monomers) glass transition temperature of at least 40°C.
  • Embodiment 92 is the polymer of embodiments 91, wherein the acrylic polymer has a calculated (aggregate of all monomers) glass transition temperature of at least 45°C.
  • Embodiment 93 is the polymer of embodiments 92, wherein the acrylic polymer has a calculated (aggregate of all monomers) glass transition temperature of at least 50°C.
  • Embodiment 94 is the polymer of any one of embodiments 80 through 93, wherein the acrylic polymer has a calculated (aggregate of all monomers) glass transition temperature of up to 95°C.
  • Embodiment 95 is the polymer of any one of embodiments 80 through 94, which has a Mn of at least 6,000 Da, at least 8,000 Da, at least 10,000 Da, or at least 12,000 Da, as determined using GPC and a series of polystyrene standards with different molecular weights.
  • Embodiment 96 is the polymer of any one of embodiments 80 through 95, which has a Mn of up to 35,000 Da, up to 30,000 Da, up to 28,000 Da, or up to 25,000 Da, as determined using GPC and a polystyrene standard.
  • Embodiment 97 is the polymer of any one of embodiments 80 through 96, which has a calculated acid number of less than 50 mg, less than 40 mg, or less than 35 mg KOH per gram resin.
  • 51 ⁇ ⁇ Embodiment 98 is the polymer of any one of embodiments 80 through 97, which has a calculated acid number of at least 8 mg, at least 10 mg, at least 20 mg, at least 30 mg, or at least 32 mg KOH per gram resin.
  • Embodiment 99 is the polymer of any one of embodiments 80 through 98, which has a calculated hydroxyl number of less than 120 mg, less than 60 mg, or less than 30 mg KOH per gram resin
  • Embodiment 100 is the polymer of any one of embodiments 80 through 99, which has a calculated hydroxyl number of at least 5 mg, at least 15 mg, or at least 28 mg KOH per gram resin
  • Embodiment 101 is a coated metal substrate comprising a metal substrate having a cured adherent coating disposed on at least a portion of a surface thereof, wherein the coating is formed from an aqueous coating composition of any one of embodiments 1 through 79.
  • Embodiment 102 is the coated metal substrate of embodiment 101, which has an average coating weight of 0.5 mg/in 2 (0.08 mg/cm 2 ) to 0.7 mg/in 2 (0.1 mg/cm 2 ).
  • Embodiment 103 is the coated metal substrate of embodiment 102, which forms a beverage can.
  • Embodiment 104 is the coated metal substrate of embodiment 101, which has an average coating weight of 4 mg/in 2 (0.62 mg/cm 2 ) to 5 mg/in 2 (0.78 mg/cm 2 ).
  • Embodiment 105 is the coated metal substrate of embodiment 104, which forms a food can.
  • Embodiment 106 is the coated metal substrate of any one of embodiments 101 through 105, wherein the metal substrate comprises a pre-treated or primed substrate.
  • Embodiment 108 is the coated metal substrate of embodiment 107, wherein the coating composition is storage stable for at least 2 months, at least 3 months, at least 4 months, or at least 6 52 ⁇ ⁇ months, at ambient temperature (and not in direct sunlight) without any phase separation as determined by the unaided human eye.
  • Embodiment 109 is the coated metal substrate of embodiment 107 or 108, wherein the phenolic crosslinker comprises a resole phenolic resin.
  • Embodiment 116 is a metal packaging comprising a coated metal substrate of any one of embodiments 101 through 115.
  • Embodiment 117 is the metal packaging of embodiment 116 comprising a metal packaging container or a portion thereof.
  • Embodiment 118 is the metal packaging of embodiment 117 comprising a can or a can end.
  • Embodiment 119 is the metal packaging of any one of embodiments 116 through 118, wherein the coated metal substrate comprises a coated surface that forms an interior surface of a container body.
  • Embodiment 120 is the metal packaging of embodiment 119, wherein the container is filled with a food or beverage product.
  • Embodiment 143 is the method of any one of embodiments 131 through 142, wherein the aqueous coating composition comprises up to 50 wt-%, up to 40 wt-%, up to 30 wt-%, up to 20 wt- %, or up to 10 wt-% of the resole phenolic crosslinker, based on total resin solids.
  • Embodiment 144 is the method of any one of embodiments 131 through 140 or 141 through 143, wherein the acrylic polymer is styrene-free, halogen-free, or both.
  • Feed B The remaining 90% of Feed B was charged using a piston fluid metering pump (available from Fluid Metering Inc. in Syosset, NY) to the flask over 2.5 hours while the flask was maintained at 96qC.
  • Feed C was used to rinse any remaining portion of Feed B in the pump into the flask.
  • Feed D was added into the flask. The reaction was held at 1.0 hour at 96qC and then cooled to 72qC.
  • Feed E was charged into the flask over 10 minutes while the flask was held at 72qC.
  • Feed E Following completion of the addition of Feed E, the reaction flask was held at 72qC for 30 minutes and then cooled to 60qC.
  • Feed F was charged to the flask and then the reaction flask was held for 30 minutes at 60qC.
  • the heating device was turned off and Feed G was charged to the flask over 2 hours while the flask was being agitated at 300 revolutions per minute (rpm). Over the 2-hour Feed G addition period, the temperature was decreased from 60qC to around 30qC.
  • the resultant dispersions were discharged after stirring an additional 30 minutes at 30qC.
  • the products were stable white dispersions. The characteristics of the resultant dispersion are shown in Table 2B.
  • Table 3A Feed Component Mass (g) 7 61 ⁇ ⁇ A Butyl cellosolve 254.1 43.5 43.5 50.8 50.8 A Deionized water 35.0 6.0 6.0 7.0 7.0 1 7 5 9 3 7 3 3 2 2 7 7 3 Table 3B Run 3 Run 4 Run 5 Run 6 Run 7 62 ⁇ ⁇ EXAMPLE 3.
  • Preparation of Acrylic-Phenolic Dispersion Comprising Methacrylic Acid and Ethyl Methacrylate The Feeds in Table 4A were used in the preparation of various acrylic-phenolic dispersions (Runs 8-13).
  • the acrylic polymer was made from methacrylic acid, hydroxypropyl methacrylate, ethyl methacrylate, styrene, and n-butyl acrylate.
  • n-butyl acrylate was removed from Feed B.
  • the resultant dispersion comprises two phenolic resins, BAKELITE PF6535 and DUREZ 34285.
  • the compositions of Runs 8 through 13 in EXAMPLE 3 were similar to those of Run 3 but acrylic acid (Run 3) was replaced with methacrylic acid in Feed B.
  • the acid number was in the range of 20 to 86 mg KOH/g resin.
  • the same procedure as described in Example 1 was used to prepare these dispersions.
  • the products were stable white dispersions.
  • Table 4A Feed Component Mass (g) 3 63 ⁇ ⁇ F DUREZ 34285 51.0 51.1 48.4 48.4 269.1 48.4 G Deionized water 371.7 420.0 346.4 343.4 2,153.1 343.4 Run 8 Run 9 Run 10 Run 11 Run 12 Run 13 Solids (wt-%) 302 287 302 301 307 307 . reparat on o cry c spers on w t out eno c
  • the Feeds in Table 5A were used in the preparation of acrylic-phenolic dispersion (Run 14).
  • the acrylic polymer was made from acrylic acid, hydroxypropyl methacrylate, ethyl methacrylate, styrene, and n-butyl acrylate.
  • the composition of Run 14 was similar to Run 3 but without phenolic resin. The same procedure was used to prepare the acrylic dispersion as described in Example 1. The product was a stable white dispersion. The characteristics of the resulting dispersion are shown in Table 5B.
  • Table 5A Feed Component Mass (g) 6 ⁇ B n-Butyl acrylate 5.6 B LUPEROX 26 3.29 Run 14 0 EXAMPLE 5.
  • Acrylic-Phenolic Dispersion Comprising Methacrylic Acid and Hydroxyethyl Methacrylate
  • the Feeds in Table 6A were used in the preparation of various acrylic-phenolic dispersions (Runs 15 and 16).
  • the acrylic polymer was made from methacrylic acid, hydroxyethyl methacrylate, ethyl methacrylate, styrene, and n-butyl acrylate.
  • the resultant dispersion comprises two phenolic resins, BAKELITE PF6535LB and DUREZ 34285.
  • the resultant dispersions comprise one cresol-based phenolic resin, either PHENODUR PR612 or PEHNODUR PR616.
  • the compositions of Run 18 to Run 20 in EXAMPLE 7 were similar to those of EXAMPLE 3.
  • BAKELITE PF6535LB and DUREZ 34285 in Feed G (EXAMPLE 3) were replaced with either PHENODUR PR612 or PHENODUR PR616.
  • the same procedure as described in EXAMPLE 1 was used to prepare these dispersions.
  • the products were stable white dispersions.
  • the characteristics of the resultant dispersion are shown in Table 8B.
  • Run 24 is similar to that of Run 3 but hydroxyethyl methacrylate was used instead of hydroxypropyl methacrylate (Run 3).
  • the same procedure as described in EXAMPLE 1 was used to prepare the acrylic dispersion.
  • the product was a stable white dispersion.
  • the characteristics of the resultant dispersion are shown in Table 10B.
  • An acid including an organic acid and/or inorganic acid, can be calculated based on the equation (molecular weight of the acid, weight percentage of the acid in the formulation should be known).
  • the acid numbers of resins may be measured using a titration method with 0.1 N KOH in methanol and phenolphthalein indicator. Based on the amount of KOH consumed, the acid number is calculated and reported as mg KOH per 1 gram of dry resin. For example, a sample (around 1.0 g) is weighted on an analytical balance and then transferred on a 100-mL beaker. The sample is dissolved in 25 mL of mixture of methyl ethyl ketone and dimethyl formamide (1:1) containing thymol blue indicator.
  • Acid number titre value of KOH solution x Normality KOH solution (0.1 N) x 56.1/ [weight of the sample (g)*solid content of the sample (%)], mg KOH/g.
  • Panel Coating An 8 u 8” tin plate panel (typically, tin coated on steel) with thickness 0.0083 inches (0.0208 mm) was placed on the glass surface of the drawdown plate.
  • a coating liquid (2–3 g) from sample Run 1 using a disposable transfer pipet was placed near the top of the tin plate sheet.
  • a Mayer drawdown rod (#22) was placed on the top of the tin plate and moved the coating liquid from the top to bottom to form a liquid film on the tin plate having a coating weight of 4-5 mg/in 2 .
  • the coated tin plate was baked in oven at 425qF for 3.5 minutes. All of the test samples were prepared by the same process.
  • 73 ⁇ ⁇ Adhesion Test The Adhesion test was conducted according to ASTM D3359-17 using SCOTCH 610 tape available from 3M (Saint Paul, MN).
  • a baked tin plate was cross hatched with a metal scribe by making 4 parallel lines and intersecting them at approximately 90 degrees with 4 additional lines.
  • a strip of 3M SCOTCH tape approximately three inches long was pressed diagonally across the scribed squares. The tape was pressed down firmly with the finger. The tape was then removed from the tin plate. The removal of the tape was a peeling back with a quick pull.
  • Adhesion is generally rated on a scale of 0B to 5B where the scale is based on the percent of the area originally coated with the sample that showed evidence of coating flaking and/or coating removal.
  • Ratings of 5B, 4B, 3B, 2B, 1B, and 0B indicate that 0%, less than 5%, 5%-15%, 15%- 35%, 35%-65%, and greater than 65%, respectively, of the area originally coated showed evidence of coating flaking and/or coating removal after completion of the test.
  • an adhesion rating of at least 4B i.e., 4B or 5B is considered to be adherent. See data in Table 11 Solvent Resistance Test (MEK Double Rubs) The extent of “cure” or crosslinking of a coating was measured as a resistance to solvents, such as methyl ethyl ketone (MEK). This test was performed as described in ASTM D 5402-93.
  • the round tip of a 2 lb. ball peen hammer was covered by attaching a felt pad square.
  • the pad was saturated with MEK.
  • the saturated pad covered tip of hammer was placed on the coated surface of the baked tin plate.
  • the hammer was guided in a 3-4 inch back-and-forth path across the surface. After 75 times of the back-and-forth cycle continued with the saturated pad, coating breakthrough occurs.
  • the number of double-rubs i.e., one back-and-forth motion
  • the MEK solvent resistance was at least 30 double rubs (DR).
  • high MEK double rubs indicated high crosslink density which generally corresponded to good solvent (e.g., chemical) resistance.
  • coating films for food cans should be highly crosslinked (at least 30 double rubs, usually at least 50 double rubs) because many food substances cause corrosion.
  • Coating film for beverage cans may have lower MEK double rubs, such as, 30 double rubs or lower.
  • the number of double rubs (i.e., one back-and-forth motion) at which failure was reached was reported. The results are shown in Table 11.
  • the back-and-forth cycle on some of test samples 74 ⁇ ⁇ was 100 times. All of the test samples from 75–100 times of MEK double rubs showed good solvent resistance.
  • Reverse Impact Test The reverse impact test measures the coated substrate’s ability to withstand the deformation encountered when impacted by steel with a hemispherical head.
  • the test was performed as described in ASTM D2794-93. Briefly, a baked tin plate was placed over the socket die of BYK Gardner OVERBALL Impact Tester instrument with the coated side down for reverse impact. The panel was held in place by hand. A one pound (0.45 kg) standard metal rod in a cylinder was dropped from a height of 36 inches (91.4 cm) onto the baked tin plate. Following the test, the coating was visually inspected for micro-cracking or microfracture – commonly referred to as crazing. Test pieces were impacted on the uncoated or reversed side. The crazing of the coating was determined via visual assessment. The film was examined for any sign of micro-crazing or crazing with particular attention paid to on stressed/formed areas.
  • the viscosity of each coating was adjusted such that the flow rate of each coating through a Ford viscosity cup (#4 orifice) was in the range of 16 to 30 seconds at 25qC.
  • the application of each coating was conducted using a laboratory-scale D&I spray unit commercially available form H.L. Fisher Co (Ronks, PA).
  • a sufficient amount of wet coating was delivered to the interior of the D&I cans to yield a total cured film weight of 300 mg per can.
  • the cans were thermally cured using a laboratory-scale D&I can oven commercially available from Midland Ross Co., New Brunswick, NJ.
  • the controls on the oven were programmed to deliver a thermal dosage that is consistent with thermal dosages 75 ⁇ ⁇ employed in the preparation of commercially coating coated tin plate D&I cans.
  • the residence time of each can within the oven was approximately 5.5 minutes.
  • Cans were baked at a minimum temperature of 213qC for approximately 2.0 minutes.
  • Global Extraction The global extraction test may be used to estimate the total amount of mobile material that can potentially migrate out of a coating and into food packed in a coated can.
  • a coated substrate is subjected to water or a solvent blend under a variety of conditions to simulate a given end-use. Acceptable extraction conditions and media can be found in 21 CFR ⁇ 175.300, paragraphs (d) and (e).
  • the total resin solids test was used to measure the wt-% of total resin solids in the compositions.
  • a coating composition was deposited into a vessel and the vessel was massed. The vessel containing the composition was subjected to a temperature of 400°F (204.4°C) for 5 minutes and then massed.
  • the wt-% total resin solids is calculated as: ⁇ ⁇ ⁇ ⁇ ⁇ 76 ⁇ ⁇ Stability
  • a sealed container e.g., glass jar
  • the liquid coating composition was stored at ambient temperature for 6 months (not in direct sunlight such as occurs with storage in a cabinet). Following 6 months, the coating composition were observed by the unaided human eye for phase separation.

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Abstract

L'invention concerne une composition de revêtement de récipient alimentaire ou de boisson aqueux, un polymère acrylique, un article revêtu (par exemple, un substrat métallique revêtu et un emballage métallique formé à partir d'un tel substrat) et des procédés (par exemple, un procédé de préparation d'une composition de revêtement et un procédé de revêtement d'une telle composition), la composition de revêtement comprenant : au moins 5 % en poids, sur la base de la totalité de solides de résine, d'un polymère acrylique ; un agent de réticulation phénolique ; et un support liquide aqueux.
EP23861313.7A 2022-08-31 2023-08-31 Compositions de revêtement comprenant un polymère acrylique et un agent de réticulation phénolique, articles, polymères acryliques et procédés Pending EP4581088A1 (fr)

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PCT/US2023/031747 WO2024050037A1 (fr) 2022-08-31 2023-08-31 Compositions de revêtement comprenant un polymère acrylique et un agent de réticulation phénolique, articles, polymères acryliques et procédés

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JPH05171102A (ja) * 1991-12-25 1993-07-09 Nippon Paint Co Ltd 水性塗料組成物及び水性塗料用樹脂の製法
JP6769604B2 (ja) * 2016-08-10 2020-10-14 桜宮化学株式会社 塗料組成物および塗装金属板
JP7232022B2 (ja) * 2018-04-13 2023-03-02 東洋インキＳｃホールディングス株式会社 水性塗料組成物、缶用部材、及び缶

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