Functionalized novolac resins, coating compositions formed therefrom, and articles and methods of coating

Abstract

The present disclosure provides functionalized novolac-type resins that are formed in-situ during thermal cure conditions of packaging coating compositions (e.g., baking conditions routinely used to cure food or beverage can coating compositions) and which are capable of self-crosslinking during such thermal cure conditions. The functionalized novolac-type resins are a reaction product (e.g., an in situ intermediate reaction product or pre-reacted product) of a crosslinking system including a first resin having hydroxy-substituted phenol groups and a reactive solvent.

Description

FUNCTIONALIZED NOVOLAC RESINS, COATING COMPOSITIONS FORMED THEREFROM, AND ARTICLES AND METHODS OF COATINGCROSS REFERENCE TO RELATED APPLICATION

[0001] This application claims priority under 35 U.S.C 119(e) to U.S. Provisional Application No. 63 / 573,758, filed on April 03, 2024. The entire contents of the aforementioned application is incorporated herein.TECHNICAL FIELD

[0002] The present disclosure relates to modified novolac-type resins that are selfcrosslinking and are useful for coating compositions, coating compositions including the selfcrosslinking novolac-type resins, articles coated with the coating compositions, and methods of coating using the coating compositions. The self-crosslinking novolac-type resins are formed in-situ by a reactive solvent and a first resin having hydroxy-substituted phenol groups.BACKGROUND

[0003] The application of coatings to metals to retard or inhibit corrosion is well established. This is particularly true in the area of metal food and beverage containers. Coatings are typically applied to the interior of such containers to prevent the food or beverage contents from contacting the metal of the container. Contact between the metal and the food or beverage product can lead, in some instances, to corrosion of the metal container, which can, in some instances, impact the packaged product. This is particularly true when the contents of the container are chemically aggressive in nature. Protective coatings are also applied to the interior of food and beverage containers to prevent corrosion of the container, for example, in the headspace of the container between the fill line of the food product and the container lid. which is particularly problematic, in some embodiments, of higher salt-content food products. Such coatings may also be advantageously applied to the exterior of food and beverage containers to provide similar protections as needed.

[0004] A wide variety of compositions have been used to coat such surfaces of food or beverage containers. For example, metal cans are sometimes coated using coil coatings orsheet coating operations where a planar coil or sheet of a suitable substrate, such as steel or aluminum metal, is coated with a suitable composition and hardened by curing in an oven. The coated substrate may then be formed into a can end or body. Alternatively, liquid coating compositions may be applied by spraying, dipping, rolling, or other suitable application methods to the formed article and then cured.

[0005] The packaging or container coatings should preferably be capable of high-speed application to the substrate and provide the necessary properties when hardened to perform in these demanding end uses. For example, the coating should be safe for food-contact; not adversely affect the taste of the packaged food or beverage product; have excellent adhesion to the substrate; resist staining and other coating defects such as "popping," "blushing" and / or "blistering;” and / or resist degradation over long periods of time, even when exposed to harsh environments. In addition, the coating should generally be capable of maintaining suitable film integrity during container or packaging fabrication and be capable of withstanding the processing conditions that the container may be subjected to during product packaging. In addition, the coating should have sufficient flexibility to survive routine can or container drop events (e.g., a can or container falling off a lower grocery store shelf for instance) without fracturing. Many current packaging coatings suffer from one or more performance defects and / or contain extractable quantities of one or more undesirable compounds particularly when the coatings are exposed to short cure cycles.SUMMARY

[0006] The present disclosure provides self-crosslinking novolac-type resin systems for coating compositions, coating compositions including such self-crosslinking novolac-type resin systems, articles having a coating formed from such compositions, and methods of coating food or beverage packaging containers or portions thereof with the coating compositions herein. Various embodiments are described herein.

[0007] In one embodiment, a food or beverage container coating composition is provided herein. In one aspect, the food or beverage container coating composition includes a first resin having hydroxy-substituted phenyl groups; a reactive solvent comprising a dialkoxymethane having a boiling point of at least about 88°C, preferably at least about130°C, and more preferably about 150°C to about 305°C; a second polymer; and wherein thefood or beverage container coating composition includes an excess of the second polymer, on a weight basis, relative to the first resin.

[0008] In other embodiments, the food or beverage container coating composition described in the previous paragraph may include one or more other features or embodiments in any combination. These other features or embodiments may include one or more of the following: wherein the first resin is a novalac resin, a resole resin, a novalac-ty pe vinyl resin, a resole-type vinyl resin, a resin derived from vinyl phenolic monomers, or combinations thereof; preferably wherein the first resin is a novalac resin; and most preferably wherein the novalac resin is obtained from reactants including a phenolic compound and an aldehyde, preferably, formaldehyde, under acidic conditions (e.g.. a pH of about 2 or less, and preferably, a pH of about 2 to about -2) and with a molar excess of the phenolic compound relative to the aldehyde (e.g., a molar ratio of the phenolic compound to the aldehyde of greater than 1 and, preferably about 1 to about 3); and / or wherein the first resin has a number average molecular weight greater than about 500 (preferably greater than about 1000) and. more preferably, less than about 4000 (most preferably less than 3000) as measured by gel permeation chromatography (GPC) using polystyrene as a standard; and / or wherein the second polymer is capable of participating in a cross-linking reaction with the first resin in the presence of the dialkoxymethane reactive solvent (e.g., at a temperature of at least about 130°C for at least about 30 seconds); and / or wherein the dialkoxymethane of the reactive solvent has the structure of Formula I(Formula I) wherein Ri and R2, independently, are a C 1 to C 10 alkyl group, a C 1 to C 10 alkylether group (e.g., an alkyl group having one or more carbon atoms replaced with an oxygen atom), preferably, a Cl to C6 alkyl group, more preferably, a C2 to C5 alkyl group, and most preferably, a C4 alkyl group; and each R3 is independently, hydrogen, or a Cl to C6 alkyl group , and preferably each R3 is hydrogen; and / or wherein the dialkoxymethane reactive solvent includes diethoxymethane, dipropoxymethane, dibutoxymethane, dipentanoxymethane, bis(butoxyethanoxy)methane, or combinations thereof, and preferably, the dialkoxymethane is dibutoxymethane; and / or wherein the first resin comprises a novalacresin, and where the phenolic compound comprises phenol, cresol, resorcinol, xylenol, t-butyl phenol, cyclohexyl -methyl phenol, dicyclopentadine, vinyl phenol, aminophenol, methoxyphenol, naphthol, cardanol, cardol, or combinations thereof and, preferably, phenol; and / or wherein the first resin comprises a novalac resin, and where the aldehyde comprises formaldehyde, acetaldehyde, propionaldehy de, paraformaldehyde, but raldehyde, oxaldehyde, trioxane (e.g., a trimer of formaldehyde), hydroxybenzaldehyde (including any isomer thereof), furfural, furfurol, or combinations thereof, and preferably, formaldehyde; and / or wherein the second polymer comprises a polyether, a polyester, an acrylic, a polyolefin, or a mixture or copolymer thereof having hydroxyl groups (preferably, primary' hydroxy groups) and / or carboxylic groups for reacting with the first resin; and / or claim, wherein the second polymer has an acid number of at least about 0 mg KOH / g. and preferably, about 0 mg KOH / g to about 150 mg KOH / g; and / or claim, wherein the second polymer has a hydroxyl number of at least about 15 mg KOH / g, and preferably, about 20 mg KOH / g to about 200 mg KOH / g; and / or wherein second polymer second has a glass transition temperature (Tg) of greater than 70°C, greater than 80°C, greater than 90°C, or greater than 100°C, and preferably, less than 150°C, less than 140°C, less than 120°C, or less than 110°C; and / or wherein the reactive solvent is substantially7formaldehyde free (e.g., about 100 ppm or less of unreacted formaldehyde, about 50 ppm or less, or about 10 ppm or less of unreacted formaldehyde) as measured pursuant to EN ISO 9397; and / or wherein the food or beverage container coating composition includes about 10 to about 50 weight percent of total resin solids (preferably, about 15 to about 35 weight percent, and more preferably about 20 to about 40 weight percent); and / or wherein the food or beverage container coating composition is substantially free of each of bisphenol A and bisphenol S; and / or wherein the coating composition includes about 5 to about 50 weight percent of the first resin (preferably, about 15 to about 35 weight percent of the first resin) and about 50 to about 95 weight percent of the second polymer (preferably, about 60 to about 80 weight percent of the second resin), based on total resin solids; and / or wherein the coating composition includes about 5 to about 35 weight percent of the reactive solvent including the Dialkoxymethane; and / or wherein the food or beverage container coating composition further including a lubricant; and / or wherein the lubricant comprises Carnauba wax, polyethylene-based wax, Fischer- tropsch wax, fatty7acid ester wax, silicon-based wax, lanolin wax, hydroxyl-functional poly siloxane wax or a combination thereof; and / or wherein the coating composition includes atleast about 25 weight percent of water; and / or wherein the coating composition further includes one or more water-miscible organic solvents; and / or wherein the water-miscible organic solvent comprises isopropyl alcohol, ethanol, methanol, butyl alcohol, amyl alcohol, a diols, a glycol ether, a glycol ester, acetone, methyl ethyl ketone, tetrahydrofuran, or a mixture thereof; and / or wherein the coating composition comprises from about 3.5 weight percent to about 15 weight percent of the one or more water-miscible organic solvents; and / or wherein the coating composition includes at least about 5 weight percent of one or more organic solvents; and / or wherein the coating composition is an organic-solvent based coating composition that includes, if any, preferably no more than 1% by weight of water, and more preferably no more than 0.1% by weight of water; and / or wherein the food or beverage container coating composition forms a cured interior food or beverage container coating that includes less than 50 ppm extractables, if any, when tested pursuant to the Global Extraction Test; and / or wherein upon baking (e.g., a temperature of at least about 135°C, and preferably, about 200°C to about 250°C), the coating composition forms a functionalized novalac resin that is reaction product of the first resin and the reactive solvent; and / or wherein the first resin (or the functionalized novalac-type resin) has a backbone including hydrocarbyl-bridged aromatic groups with alkoxymethylene substituents; and / or wherein the hydrocarbyl-bridge is a methylene group; and / or wherein the backbone is free of ether bridges between aromatic groups; and / or wherein the first resin is a novalac-type vinyl resin, a resole-type vinyl resin, a vinyl phenolic resin, or combinations thereof; and / or when applied to tin plate (ETP) and cured at 200°C for 10 minutes to achieve an average dry film thickness of 6 mg / in2, exhibits at least about 50 MEK double rubs when measured pursuant to ASTM D5402; and / or wherein the coating composition includes less than about 1000 ppm of free formaldehyde, preferably less than 500 ppm of formaldehyde, and most preferably less than 100 ppm of free formaldehyde determined using the procedures of EN ISO 9397.

[0009] In another embodiment, the present disclosure provides for an article comprising a food or beverage container, or a portion thereof, where the article includes a metal substrate; and a thermally-cured coating disposed on at least a portion of the metal substrate, wherein the thermally-cured coating is formed by baking the food or beverage container coating composition as described in any embodiment of the previous two paragraphs at an oven temperature of at least about 135°C, and preferably about 200°C to about 250°C.

[0010] In other embodiments, the article of the previous paragraph may include other features or embodiments in any combination. These other features or embodiment include one or more of the following: wherein, during the baking, the coating composition forms a functionalized novalac-type resin; and / or wherein the functionalized novalac-type resin has a backbone including hydrocarbyl-bridged aromatic groups with alkoxymethylene substituents or a backbone having pendant aromatic groups; and / or wherein the hydrocarbyl-bridge is a methylene group; and / or wherein the backbone is free of ether bridges between aromatic groups; and / or wherein the functionalized novalac-type resin has the structure of Formula II(Formula II) wherein R4 is a Cl to CIO alkyl group or a Cl to CIO alkylether group (e.g., an alkyl group having one or more carbon atoms replaced with an oxygen atom) and, preferably, a Cl to C6 alkyl group, more preferably, a C2 to C5 alkyl group, and most preferably, a C4 alkyl group; and / or wherein the food or beverage container coating composition is applied on a food or beverage-contacting surface of the metal substrate; and / or wherein the metal substrate is tin plate (ETP) and has a thickness of 0.17 to 0.8mm; and / or wherein the coating composition, when dned, as a coating thickness of 4 to 8 mg / in2.

[0011] In yet further embodiments, a method of forming a food or beverage container is described herein. In one aspect, the method includes providing the food or beverage container coating composition as described in any embodiment of this Summary; and applying the food or beverage container coating composition on a metal substrate, or portion thereof, prior to, or after, forming the metal substrate into a food or beverage container or a portion thereof. The method may also include causing the coating composition as described in any embodiment of this Summary to be used on a metal substrate for a food or beverage container or a portion thereof.

[0012] In yet other embodiments, the method as described in the previous paragraph may include other steps, features, or embodiments in any combination. These other steps, features, or embodiments may include one or more of the following: further comprising baking and curing the food or beverage container coating composition after applying to the metal substrate; and / or wherein the metal substrate is heated at an oven temperature of at least about 130°C for at least about 30 seconds; and / or wherein, during the baking, the coating composition forms a functionalized novalac-type resin; and / or wherein the functionalized novalac resin has a backbone including hydrocarbyl-bridged aromatic groups with alkoxy methylene substituents or a backbone having pendant aromatic groups; and / or wherein the hydrocarbyl-bridge is a methylene group; and / or wherein the backbone is free of ether bridges between aromatic groups; and / or wherein the metal substrate is tin plate (ETP) and has a thickness of 0. 17 to 0.8mm; and / or wherein the coating composition, when dried, as a coating thickness of 4 to 8 mg / in2

[0013] The above summary of the present invention is not intended to describe each disclosed embodiment or every implementation of the present invention. The description that follows more particularly exemplifies illustrative embodiments. In several places throughout the application, guidance is provided through lists of examples, which examples can be used in various combinations. In each instance, the recited list serves only as a representative group and should not be interpreted as an exclusive list.

[0014] The details of one or more embodiments of the invention are set forth in the description below. Other features, objects, and advantages of the invention will be apparent from the description and from the claims.BRIEF DESCRIPTION OF DRAWING FIGURE

[0001] FIG 1. is a chart of graph of storage modulus over time for coating compositions including acrylic or epoxy second polymers combined with first resins of either a phenolic novolac DBM pre-reacted cross-linking system or a phenolic novolac DBM blended crosslinking system.SELECTED DEFINITIONS

[0015] Unless otherwise specified or apparent from the context, the following terms as used herein have the meanings provided below.

[0016] Unless otherwise indicated, a reference to a "(meth)acrylate" compound (where “meth” is bracketed) refers to a shorthand reference including both acrylate and methacrylate compounds.

[0017] As used herein, the term “organic group” means a hydrocarbon group (with optional elements other than carbon and hydrogen, such as oxygen, nitrogen, sulfur, and silicon) that is classified as an aliphatic group, cyclic group, or combination of aliphatic and cyclic groups (e.g., alkaryl and aralkyl groups). The term “aliphatic group” means a saturated or unsaturated linear or branched hydrocarbon group. This term is used to encompass alkyl, alkenyl, and alkynyl groups, for example. The term “alkyl group” means a saturated linear or branched hydrocarbon group including, for example, methyl, ethyl, isopropyl, t-butyl, heptyl, dodecyl, octadecyl, amyl, 2-ethylhexyl, and the like. The term “alkenyl group” means an unsaturated, linear or branched hydrocarbon group with one or more carbon-carbon double bonds, such as a vinyl group. The term “cyclic group” means a closed ring hydrocarbon group that is classified as an alicyclic group or an aromatic group, both of which can include heteroatoms.

[0018] A group that may be the same or different is referred to as being “independently” something. Substitution is anticipated on the organic groups of the compounds of the present disclosure. As a means of simplifying the discussion and recitation of certain terminology used throughout this application, the terms “group” and “moiety” are used to differentiate between chemical species that allow for substitution or that may be substituted and those that do not allow or may not be so substituted. Thus, when the term “group” is used to describe a chemical substituent, the described chemical material includes the unsubstituted group and that group with O, N, Si, or S atoms, for example, in the chain (as in an alkoxy group) as well as carbonyl groups or other conventional substitution. Where the term “moiety ” is used to describe a chemical compound or substituent, only an unsubstituted chemical material is intended to be included. For example, the phrase “alkyl group” is intended to include not only pure open chain saturated hydrocarbon alkyl substituents, such as methyl, ethyl, propyl, t-butyl, and the like, but also alkyl substituents bearing further substituents known in the art, such as hydroxy, alkoxy, alkylsulfonyl, halogen atoms, cyano, nitro, amino, carboxyl, etc. Thus, “alkyl group” includes ether groups, haloalkyls, nitroalkyls, carboxyalkyls, hydroxyalkyls, sulfoalkyls, etc. On the other hand, the phrase “alkyl moiety” is limited to theinclusion of only pure open chain saturated hydrocarbon alkyl substituents, such as methyl, ethyl, propyl, t-butyl, and the like.

[0019] The term “component” refers to any compound that includes a particular feature or structure. Examples of components include compounds, monomers, oligomers, polymers, and organic groups contained there.

[0020] The term “ethylenically unsaturated” refers to compounds that include a non-aromatic carbon-carbon double bond (i.e. -C=C-), with vinylic double bonds being preferred.

[0021] As used herein, a “phenolic group” refers to a group having a C6 aromatic ring with one or more hydroxyl groups attached directly to the ring.

[0022] The term "substantially free" when used with respect to a coating composition that may contain a particular compound means that the coating composition contains less than 1,000 parts per million (ppm) of the recited compound (corresponding to less than 0. 1 wt. %) regardless of the form of the compound (e.g., whether present in unreacted form or reacted form). The term "essentially free" when used with respect to a coating composition that may contain a particular compound means that the coating composition contains less than 100 parts per million (ppm) of the recited compound regardless of the form of the compound. The term "essentially completely free" when used with respect to a coating composition that may contain a particular compound means that the coating composition contains less than 5 parts per million (ppm) of the recited compound regardless of the form of the compound. The term "completely free" when used with respect to a coating composition that may contain a particular compound means that the coating composition contains less than 20 parts per billion (ppb) of the recited compound regardless of the form of the compound. When the phrases "free of’ (outside the context of the aforementioned phrases), "do not contain", "does not contain", "does not include any" and the like are used herein, such phrases are not intended to preclude the presence of trace amounts of the pertinent structure or compound which may be present but were not intentionally used, e.g., the presence of environmental contaminants. As will be appreciated by persons having ordinary skill in the art, the amount of a compound in an ingredient, polymer, formulation or other component typically may be calculated based on the amounts of starting materials employed and yields obtained when making such ingredient, polymer, formulation or other component. The term “food-contactsurface” refers to a surface of an article (e g., a food or beverage container) that is in contact with, or suitable for contact with, a food or beverage product. When used in the context of a coating composition applied on a food-contact surface of a packaging article (e.g., a food or beverage container), the term refers to the underlying substrate (typically associated with an interior surface of the packaging article) on which the coating composition is applied and does not imply that the underlying portion of the substrate will be in contact with a food or beverage product.

[0023] The term “on”, when used in the context of a coating applied on a surface or substrate, includes both coatings applied directly or indirectly to the surface or substrate. Thus, for example, a coating applied to a primer layer overlying a substrate constitutes a coating applied on the substrate.

[0024] Unless otherwise indicated, the terms “polymer” and “polymeric material” include, but are not limited to, homopolymers, copolymers (such as for example, block, graft, random or statistical and alternating copolymers, terpolymers, etc ), and blends and modifications thereof. Furthermore, unless otherwise specifically limited, the term “polymer” shall include all possible geometrical configurations of the material. These configurations include, but are not limited to, isotactic, syndiotactic, and atactic symmetries. In general, polymers have number average molecular weights of about 1,000 g / mol or greater. As also used herein, “oligomers” refer to lower molecular weight polymers and, in general, have a number average molecular weight of less than about 1,000 g / mol. As used herein, the term “resin” or “resins” refers to compositions including both polymers and / or oligomers.

[0025] The term “monomer constituent unit” refers to a structural unit resulting from polymerization of monomers. As used herein, “monomer” or reactant generally refers to a compound within a reaction mixture prior to polymerization, and monomer units or (alternatively) structural units refers to the monomer or reactant within the polymer. If the discussion herein refers to a monomer or reactant, it also implies the resultant monomer unit, structural unit, or repeating unit thereof in the polymer. Likewise, if the discussion refers to a monomer unit, structural unit, or repeating unit, it also implies the monomer or reactant mixture used to form the polymer with the associated units therein.

[0026] As used herein, “cross linker” or “crosslinker” refers to molecule or compound capable of forming a covalent linkage between polymers or between two different regions of the same polymer. Self-crosslinking refers to the abil ity of the molecule or compound to form such covalent linkage without the need for any additional curing agent. Selfcrosslinking compounds are capable of forming such covalent linkage or bonds w ith application of sufficient heat alone (or, in some cases, catalysts may also be added).Preferred self-crosslinking functionalized novolac resins descnbed herein are capable of selfcrosslinking under typical thermal cure bake conditions employed for food or beverage container coatings (e.g., oven temperatures of 170 to 230°C and curing times of 1 to 30 minutes).

[0027] The term “protected” when used in the context of a "protected methylol group” encompasses both (i) a methylol group (viz., -CH2-OH) that has been protected with a blocking agent (e.g., n-butanol) to avoid premature consumption (e g., irreversible reaction) of the methylol group prior to thermal cure such that the methylol group is available for participating in crosslinking reactions during thermal cure conditions frequently employed to cure food or beverage container coating compositions (e.g., oven baking temperatures of from 170°C to 230°C) and (ii) an alkoxymethylene group that is not necessarily provided via a reaction involving formation of a methylol group, but which yields a methylol group available for participating in crosslinking reactions during thermal cure conditions frequently employed to cure food or beverage container coating compositions (e.g., oven baking temperatures of from 170°C to 230°C).

[0028] The term “substituent” in the context of a “substituent methylol group” refers to a methylol group that is directly attached to an atom of an aryl ring. For example, a methylol group in which the carbon of the methylol group is directly attached to a carbon of a phenyl ring is a substituent methylol group. Similarly, the term “substituent” when used in the context of a “substituent protected methylol group” refers to a protected methylol group in which a methylene carbon of the protected methylol group is directly attached to a carbon of a phenyl ring.

[0029] As discussed more below, the functionalized novolac resins herein are stable at room temperature (e.g., about 20°C to about 25°C) for at least about 90 days. As used herein,“stable'’ refers to a composition with no more than a 100 percent viscosity increase relative to a starting viscosity at time TO, and preferably, a change in viscosity of about 0 to less than 100 percent viscosity' increase relative to the starting viscosity at time TO with viscosity measured on a Brookfield viscometer at room temperature and with the spindle size and rpm selected according to the parameters of ASTM D2983. (For instance, if initial viscosity is 100 cPs, a viscosity increase to below 200 cPs is acceptable (e.g.. no more than a 100% increase) while a viscosity increase over 200 cPs is unacceptable).

[0030] The term “comprises” and variations thereof do not have a limiting meaning where these terms appear in the description and claims.

[0031] The terms “preferred” and “preferably” refer to embodiments of the invention that may afford certain benefits, under certain circumstances. However, other embodiments may also be preferred, under the same or other circumstances. Furthermore, the recitation of one or more preferred embodiments does not imply that other embodiments are not useful, and is not intended to exclude other embodiments from the scope of the invention.

[0032] As used herein, the term "or" is generally employed in its usual sense including "and / or" unless the content clearly dictates otherwise.

[0033] As used herein, “a,” “an,” “the,” “at least one,” and “one or more” are used interchangeably. Thus, for example, a coating composition that comprises “an” additive can be interpreted to mean that the coating composition includes “one or more” additives.

[0034] Also herein, all numbers are assumed to be modified by the term “about” and in certain embodiments, preferably, by the term “exactly.” As used herein in connection with a measured quantity, 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. Herein, “up to” a number (e.g., up to 50) includes the number (e.g., 50).

[0035] Also herein, the recitations of numerical ranges by endpoints include all numbers subsumed within that range (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, 5, etc.).Furthermore, disclosure of a range includes disclosure of all subranges included within the broader range (e.g., 1 to 5 discloses 1 to 4, 1.5 to 4.5, 1 to 2, etc.).DETAILED DESCRIPTION

[0036] Conventional novolac resins do not self-crosslink during thermal bake conditions typically used in conjunction with food or beverage container coating compositions. To enter into crosslinking reactions, such conventional novolac resins require the presence of additional curing agents that are reactive with the novolac resins such as, for example, resole phenolic resins, certain aminoplast resins, and the like. While not novolac resins per se, other resins have hydroxyl substituted phenolic groups similar to those of conventional novolac resins, which are similarly non-reactive without additional curing agent. Examples of such other “novolac-type” resins include vinyl phenolic resins such as. e.g., hompolymers or copolymers formed from hydroxystyrenes (e g., p-hydroxy styrene) and the like.Accordingly, as used herein, the term “novolac-type” resins includes both conventional novolac resins and such other novolac-tj pe resins noted above that are similarly non-reactive without the use of additional curing agents.

[0037] In one aspect, the present disclosure provides functionalized novolac-ty pe resins that are formed in-situ during thermal cure conditions of packaging coating compositions (e.g., baking conditions routinely used to cure food or beverage can coating compositions) and which are capable of self-crosslinking during such thermal cure conditions. In preferred embodiments, the functionalized novolac-type resins are a reaction product (e.g., an in situ intermediate reaction product) of a crosslinking system including a first resin having hydroxy-substituted phenol groups (typically with at least one hydrogen atom located at an ortho or para location on the phenolic ring relative to an -OH group) and a reactive solvent. In preferred embodiments, the reactive solvent is a dialkoxymethane. While not intending to be bound by theory, it is believed that such reactive solvent, during thermal bake conditions routinely used for can coating compositions, can provide reactivity via substitution at unsubstituted ortho or meta ring positions relative to a hydroxyl group of a phenolic group. In particular, the present disclosure provides for such self-crosslinking novolac-type resins, food or beverage container coating compositions including such resins and / or a crosslinking system for forming such resins in situ during thermal cure, and the food or beverage containers (or portions thereof) coated with such compositions. The unique novolac-type resins of the present disclosure are suitable for the food or beverage container coating compositions, articles having a coating formed from such coating compositions, and methodsof coating food or beverage containers with the coating compositions. In addition to the novolac-type resins disclosed herein, resole-type phenolic resins (including vinyl resins having resole-type phenolic functionality) may also benefit from the reactive solvents of the present disclosure. For example, the use of such reactive solvents may help further activate certain resole phenolic resins for crosslinking and may also help incorporate any residual unreacted phenol compounds into the cured coating so they are not present in the final coating as unreacted compounds that can potentially migrate out of the cured coating (and. thus, resole phenolic resins are also included in the starting novolac-type resins herein). Herein, a food or beverage “container” is used to encompass containers for food or beverage products including but not limited to metal beverage cups and one, two, or three-piece containers (including, but not limited to. the tapered recycled aluminum cups described in US 10,875,076), metal food drums in additional to conventional food or beverage cans (e g., two- piece drawn food cans, three-piece food cans, food can ends, drawn and ironed cans, beverage can ends, and the like), and metal closures for glass food or beverage containers. All such containers may be coated with the food or beverage container coating compositions of the present disclosure.

[0038] In one approach or embodiment, the food or beverage container coating composition is provided that includes a first resin having hydroxy-substituted phenyl groups (e.g.. the novolac-type resin); a reactive solvent comprising a dialkoxy methane having a boiling point of at least about 88°C, and preferably, about 100°C to about 305°C (more preferably, about 130°C to about 210°C, and even more preferably, about 150°C to about 200°C or about 150°C to about 190°C); a second polymer; and wherein the food or beverage container coating composition includes an excess of the second polymer, on a weight basis, relative to the first resin. As used herein and discussed more below, the first resin having hydroxysubstituted phenol groups includes any resin having phenolic groups and / or functionalized phenolic groups. For instance, the first resin in the novolac-type resins herein and may include anovalac resin, a resole resin, a novalac-type vinyl resin, a resole-type vinyl resin, a resin derived from vinyl phenolic monomers (e.g., polyvinyl phenol resins), or combinations thereof, and preferably wherein the first resin is a conventional novalac resin, and most preferably wherein the conventional novalac resin is obtained from reactants including a phenolic compound and an aldehyde, preferably, formaldehyde, under acidic conditions (e.g.,a pH of about 2 or less, and preferably, a pH of about 2 to about -2) and with a molar excess of the phenolic compound relative to the aldehyde (e.g.. a molar ratio of the phenolic compound to the aldehyde of greater than 1 and, preferably about 1 to about 3). Examples of suitable novolac-ty pe resins that are suitable for the in-situ functionalization of the present disclosure are shown in the table below:

[0039] Table 1: General Exemplary Novolac-Type Starting Reactants

[0040] As discussed more herein, the self-crosslinking novolac-type resin is a functionalized novolac-type resin, preferably a functionalized novolac resin via the reactive solvent and having substituent methylol groups, and most preferably, wherein the substituent methylol groups include an alkoxymethylene substituent group obtained in-situ between the first resin and the reactive solvent. While in presently preferred embodiments, the self-crosslinking novolac-type resin is an intermediate reaction product formed in situ during thermal cure of a coating composition include the first resin and the reactive solvent, it is also contemplated that, in some embodiments, at least some, or even all. of the reactive solvent can be prereacted with the first resin prior to preparation of the final coating composition and / or thermal bake of the coating composition. In some approaches, suitable functionalized novolac-type resins herein are a reaction product using an acidic catalyst of (i) a conventional novolac resin (e.g., a phenolic compound reacted with an aldehyde, preferably formaldehyde) a reactive solvent including a dialkoxymethane. Preferably, the functionalized novolac resins are reaction of the conventional novolac resin and the reactive solvent using an acidic catalyst.

[0041] First Resin

[0042] The first resin herein is any novolac-type resin as described above having phenolic groups (i.e., a group having a C6 aromatic ring with one or more hydroxyl groups attached directly to the ring) as shown above. Examples of suitable phenolic groups include substituted or unsubstituted hydroxy phenyl groups and substituted or unsubstituted hydroxyl phenylene groups (in some approaches, multi-substituted on the phenol ring). To benefit from the functionalization of the present disclosure using reactive solvent, preferably at least some of the phenolic groups include unsubstituted ortho and / or meta ring positions relative to a hydroxyl group attached to the ring. In some embodiments, the first resin is selected from (i.e., the novolac-type resins herein) a conventional novalac resin, a conventional resole resin, a novalac-type vinyl resin, a resole-type vinyl resin, any other resole-type or novolac-type resin derived from vinyl phenolic monomers, or combinations thereof. The phenolic groups may be located in a resin backbone, pendant to a resin backbone (i.e., as pendant groups), or a combination thereof. The first resin may be a linear resin or a branched resin. In some embodiments, the first resin is a conventional novolac resin. In some embodiments, the first resin is a reaction product of components including at least one ethylenically unsaturated monomer having pendant phenolic groups, with vinyl monomers having pendant phenolic groups being preferred such monomers. Such resole-type or novolac-type vinyl resins may be at least partially prepared from the poly merization of an ethy lenically unsaturated monomer component including one or more monomers having a phenolic group, with vinyl monomers having a phenolic group being preferred. In some embodiments, the first resin is an acrylic copolymer having hydroxyl phenyl functionality.

[0043] The first resin may also be a functionalized polyester including pendant hydroxyphenyl groups such as described in US 9,938,430. which is incorporated by reference herein. The first resin may also be any of the polymers having hydroxyl phenyl functionality' disclosed in US Pub. No. 2016 / 0024337, US 7,371,800, or US 11,459,478.

[0044] Novolac Resin: In some embodiments, the first resin is a conventional novolac resin. Such resins may be formed by reacting a phenolic compound and an aldehyde under acidic conditions and with a molar excess of the phenolic compound relative to the aldehyde to form the conventional novolac. As used herein, acidic conditions include reactions having a pH of about 2 or less, and preferably, a pH of about 2 to about -2, and a molar excess of the phenolic compound means a molar ratio of the phenolic compound to the aldehyde of greaterthan 1 and, preferably about 1 to about 3. The conventional novolac resin may be formed using an acid catalyst including, but not limited to, strong mineral acids (e.g., sulfuric acid, phosphoric acid and / or hydrochloric acid) as well as strong organic acid catalysts such as oxalic acid, p-toluene sulfonic acid, and inorganic salts such as zinc acetate, zine borate, and the like. Conventional novolac resins are thermoplastic polymers than can be melted (if in solid form) but will not crosslink upon the application of heat alone and will only crosslink with the additional of a novolac curing agent (e.g., another crosslinker reactive with a novolac such as a resole phenolic resin). Conventional novolac resins generally have the structure below:

[0045] Suitable phenolic compounds to form the starting (e.g., conventional) novolac resins herein including phenol, cresol, resorcinol, xylenol, t-butyl phenol, cyclohexyl-methylphenol, dicyclopentadiene, vinyl phenol, aminophenol, methoxyphenol, naphthol, cardanol, cardol, or combinations thereof. Preferably, the phenolic compound to form the conventional novolac resins herein is phenol, cresol, or a mixture thereof. Suitable aldehyde reactants for forming the starting (e.g., conventional) novolac resins include formaldehyde, acetaldehyde, propionaldehyde, paraformaldehyde, buty raldehyde, oxaldehyde, trioxane (e.g., a trimer of formaldehyde), hydroxybenzadehyde (including any isomers), furfural, furfurol, or combinations thereof. Typically, the aldehyde compound for forming the conventional novolac resins herein is formaldehyde.

[0046] Suitable such conventional novolac resins are readily commercially available. When the first resin is a novolac resin, then the first resin has a number average molecular weight (‘’Mn”) greater than about 500, and more preferably^ greater than about 1000 as measured by gel permeation chromatography (GPC) using polystyrene standards. When the first resin is a novolac resin, then the first resin will typically have an Mn of less than about 4000, and more typically less than about 3000 as measured by gel permeation chromatography (GPC) using polystyrene standards. Examples of such commercially available conventional novolac resins include the Alnovol PN320 novolac resin product commercially available from Allnex, theHRJ 12952 novolac resin product commercially available from SI Group, the Durite SD1708 novolac resin product commercially available from Bakelite Synthesis, and the Durite SD1731 novolac product commercially available from Bakelite Synthesis.

[0047] Vinyl Phenolic Resins: The first resin may also be a vinyl phenolic resin. In approaches, the vinyl phenolic resin includes the reaction product of components including at least vinyl monomers having phenolic groups, wherein the phenolic groups may be substituted with a methylol or methylol ether group to provide novolac and / or resole functionality. Typically, at least some of the phenolic groups of the vinyl phenolic resin will be '’novolac- t pe" phenolic groups - that is phenolic groups that are not reactive during thermal bake conditions in the absence of the reactive solvent. Such resin may be prepared, in some optional approaches, as described in US 63 / 456,962, which is incorporated herein by reference.

[0048] The vinyl phenolic resins of the present disclosure are vinyl resins with novolac- or resole-type functionality (e.g., phenolic moieties with novolac or resole structures as described above). Generally, the vinyl phenolic resins may be formed, in exemplary7embodiments, by first forming a vinyl resin from an ethylenically unsaturated monomer component that includes a vinyl phenolic monomer (for example, a hydroxy styrene monomer), optionally in combination with one or more other ethylenically unsaturated monomers, and then modifying the monomer constituent unit provided by the vinyl phenolic monomer as described herein. The term “vinyl resin’' as used herein refers to a polymerization product such as an oligomer or polymer prepared by addition polymerizing (e.g.. free radical polymerizing with the assistance of an initiator) an ethylenically unsaturated monomer component (e.g., a mixture of ethylenically unsaturated monomers and / or oligomers). As used herein, vinyl phenolic resins may also be derived from other non-vinyl monomers such as, for instance, 4-hydroxyphenyl methyl carbinol, so long as the resultant vinyl phenolic resins has the structure as described below.

[0049] In some embodiments, vinyl phenolic resins of the present disclosure have a backbone (e.g., longest chain) comprised of carbon-carbon single bonds due to the addition polymerization used to form the vinyl resin from an ethylenically unsaturated monomer component. In some approaches, the vinyl phenolic resins of the present disclosure have abackbone (e.g.. longest chain) that is free of formaldehyde or structures derived from formaldehyde. In some embodiments, the first resin (e.g., prior to reaction with reactive solvent) is free of structural units derived from formaldehyde. The vinyl phenolic resins may first be partially formed as the polymerization product of an ethylenically unsaturated monomer component including one or more monomers having a phenolic group. In embodiments, the vinyl phenolic resins is the reaction product of monomers including monomers comprising one or more phenolic and optional, other monomers, wherein the other monomers comprise ethylenically unsaturated monomers.

[0050] The molecular weight of the vinyl phenolic resin can vary depending upon material choice and the desired end use. In embodiments, the vinyl phenolic resin has a number average molecular weight (Mn) of at least about 500 g / mol, more preferably at least about 800 g / mol, more preferably at least about 1,000 g / mol, more preferably at least about 1,500 g / mol, and even more preferably at least about 3,000 g / mol. Preferably, the Mn of the vinyl phenolic resin is less than about 500,000 g / mol, more preferably less than about 100.000 g / mol, more preferably less than about 20,000 g / mol, more preferably less than about 15,000 g / mol, more preferably less than about 10,000 g / mol, and even more preferably less than about 8,000 g / mol. The number average molecular weight can be determined by gel permeation chromatography (GPC) using polystyrene standards.

[0051] In embodiments, suitable monomers comprising one or more phenolic groups may further comprise ethylenic unsaturation allowing polymerization via free radical polymerization or cationic polymerization. Exemplary such monomers include p- hy dr oxy styrene (4-vinyl phenol), 4-acetoxystyrene. or p-tert-butyl hydroxystyrene monomers, and substituted variants thereof. In further embodiments, exemplary such monomers include 2-vinyl phenol and 3-vinyl phenol.

[0052] In embodiments, the optional other monomers included in the ethylenically unsaturated monomer component used to form the vinyl phenolic resin may separately, and preferably, include one or more ethylenically unsaturated monomers, such as, for example, (meth)acrylates s (e.g., alkyl, cycloalkyl, alkoxy, and aromatic (meth)acrylates), vinyl esters of saturated carboxylic acids, monoolefins, conjugated dienes, styrene, (meth)acrylamide, methylol (meth)acrylamide, styrene, a-methyl styrene, vinyl toluene, vinyl propionate, vinylacetate, acrylonitrile, vinyl chloride (the use of halogen-containing monomers is not presently preferred), and the like. The use of (meth)acrylamide monomers is not presently preferred. In an embodiment, the other monomers include one or more polyfunctional (meth)acrylate monomers. In some embodiments, the other monomers also include one or more ethylenically unsaturated carboxy-functional amide monomers, e.g., ureido-functional monomers, such as monomers formed as the product of the reaction between aminoalkyl alkylene urea (e.g.. amino ethylene urea, for example) with an ethylenically unsaturated carboxylic acid or anhydride (e.g., maleic anhydride, for example). Examples of suitable (meth)acrylate and (meth)acrylic monomers include acrylic acid, methacrylic acid, methyl acrylate, ethyl acry late, propyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, benzyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, 2- ethylhexyl methacrylate, hydroxy ethyl acrylate, hydroxyethyl methacrylate, hydroxybutyl acrylate, hydroxybutyl methacrylate, cyclohexyl methacrylate (CHMA), glycidyl methacry late, 4-hydroxybutyl acrylate glycidyl ether, allyl methacry late, and mixtures thereof. Preferred monomers include styrene, methyl methacrylate, ethyl acrylate, methacrylic acid, n-butyl acrylate, tert-butyl acrylate, tert-butyl methacrylate, n-butyl methacrylate, esters of itaconic acid, vinyl acetate, 2-ethyl hexyl acry late, CHMA, bio-based monomers, and the like. Suitable multi-ethylenically unsaturated monomers include polyfunctional acrylates such as. for example, di-, tri- and tetra-functional acrylates.

[0053] In some approaches or embodiments, the vinyl phenolic resin includes at least one monomer constituent unit having the structure of Formula I, shown below:(Formula I) wherein R1is a hydrogen or an organic group including 1 to 20 carbon atoms (in further embodiments, 1 to 12 carbon atoms, or 1 to 8 carbon atoms, or 1 to 4 carbon atoms) and wherein R2, if present, is an organic group including 1 to 6 carbon atoms (in furtherembodiments, 1 to 3 carbon atoms, or 1 to 2 carbon atoms), and wherein R3 and R4 are each, independently, hydrogen or an organic group such as. e.g., a branched or linear alkyl or substituted alkyl including 1 to 8 carbon atoms (in further embodiments, 1 to 6 carbon atoms, or 1 to 4 carbon atoms, and in still further embodiments 1 to 2 carbon atoms). In preferred embodiments, at least one of R3 and R4 is hydrogen, and in certain preferred embodiments, both R3 and R4are each hydrogen. Typically, R1will be hydrogen. In further preferred embodiments, R1is located in the para position relative to the carbon of the phenolic ring linking the phenolic ring to the backbone of the vinyl phenolic resin. In preferred embodiments, the -OR1group attaches to the phenyl ring at an ortho or para position relative to the phenyl ring carbon atom at which the structure attaches to the vinyl resole phenolic resin backbone (i.e. , the phenyl ring carbon atom closest to R2, if present).

[0054] In some embodiments of the vinyl phenolic resin, monomers from which the one or more monomer constituent units having Formula I are derived make up at least about 20 weight percent (“wt %”), in further embodiments, at least about 40 wt %, in further embodiments, at least about 50 wt %, in further embodiments, at least about 65 wt %, and in yet further embodiments, at least about 85 wt % of the total weight of all monomers polymerized to form the vinyl phenolic resin. In some embodiments of the vinyl phenolic resin, monomers from which the one or more monomer constituent units having Formula I are derived make up at most about 100 wt %, in further embodiments, at most about 95 wt %, in further embodiments, at most about 80 wt %. and in yet further embodiments, at most about 70 wt % of the total weight of all monomers polymerized to form the vinyl resole phenolic resin. In some preferred embodiments, in addition to monomer constituent units having Formula I, the vinyl phenolic resin also includes one or more monomer constituent units derived from styrene, a (meth)acrylate, a (meth)acrylic acid, or mixtures thereof.

[0055] First Resin Functionalization: The first resin (e.g., the novolac-type resins selected form a conventional novolac, a conventional resole, or a vinyl phenolic resins, and the like describe above) is functionalized into the self-crosslinking novolac-type resins of the present disclosure by further reacting the first resin with a reactive solvent including the dialkoxymethane compound and using an acid catalyst. The reaction may occur at any suitable time, including, for example, during: (i) formation of a functionalized novolac resin for subsequent formulation to form a coating composition, (ii) thermal cure of a coatingcomposition including the reactive solvent and the intermediate, and preferably the acid catalyst, or (iii) both (i) and (ii). The formed functionalized or self-crosslinking novolac resin can crosslink with the second polymer as noted herein without the need for common novolac curing agents and, preferably, can self-crosslink to the second polymers herein with only the application of heat, such as curing temperatures of about 130 to about 200°C, in other approaches, 175 to about 220°C. and in yet further approaches, 180 to about 250°C. As used herein, without the need for conventional novolac curing agents means the compositions herein are substantially free of (and preferably free of) or do not contain formaldehyde curing agents, paraformaldehyde curing agents, hexamethylentetramine (HMTA) curing agents, combinations thereof, and the like curing agent conventionally used with conventional novolac resins.

[0056] In one approach or embodiment, the reactive solvent includes select dialkoxymethane compounds having molecular weights and boiling points suitable to functionalize the novolac-type resins into the self-crosslinking novolac-type resins when using an acidic catalyst, such as a strong acid. In preferred embodiments, the dialkoxymethane of the reactive solvent has the structure of Formula I(Formula I) wherein Ri and R2 of Formula I. independently, are a Cl to CIO alkyl group, a Cl to CIO alkylether group (e.g., an alkyl group having one or more carbon atoms replaced with an oxygen atom). Preferably, each Ri and R2 is, independently, a Cl to C6 alkyl group, more preferably, a C2 to C5 alkyl group, and most preferably, a C4 alk l group. Each R3 of Formula I is independently, hydrogen, or a Cl to C6 alkyl group, and preferably each R3 is hydrogen. Preferred dialkoxymethanes of the reactant solvent have a molecular weight of about 100 to about 200 g / mol, preferably, about 130 to about 190 g / mol and have a boiling point of at least about 88°C, and preferably, about 170°C to about 305°C (more preferably, about 170°C to about 210°C, and even more preferably, about 170°C to about 200°C or about 175°C to about 190°C). Suitable dialkoxymethanes include diethoxymethane (DEM) having a molecular weight of 104. 15 and a boiling point of 88°C, dipropoxymethane (DPM) havinga molecular weight of 132.20 and a boiling point of 141°C, bitutoxymethane (DBM) having a molecular weight of 160.26 and a boiling point of 179°C, dipentanoxymethane (DPTM). and / or bis(butoxyethanoxy)methane ( DBEM). or combinations thereof. In one embodiment, a preferred reactive solvent includes dibutoxymethane. In one embodiment herein, the food or beverage container coating compositions include at least about 5 weight percent of the reactive solvent including the dialkoxymethane, based on total weight, including the selfcrosslinking novolac resin, preferably at least about 10 weight percent, and more preferably, at least about 15 weight percent. In other embodiments, the food or beverage coating coating composition may also include about 35 weight percent or less of the reactive solvent including the dialkoxymethane, based on total weight, including the self-crosslinking novolac resin, preferably about 25 weight percent or less, and more preferably, about 20 weight percent or less. In another embodiment, the food or beverage container coating composition have a mol ratio of the dialkoxymethane to the conventional novolac resin (e.g., dialkoxymethane / novolac) of at least about 0.07, in other approaches, at least about 0.2, in yet other approaches, at least about 0.4, and in yet further approaches, at least about 0.6. In embodiments, the reactive solvent is a low or formaldehyde-free reactant (e.g., less than about 100 ppm of unreacted formaldehyde, less than about 50 ppm, less than about 20 ppm, less than about 10 ppm, or no detectable amounts of unreacted formaldehyde in the starting reactant).

[0057] Examples of suitable acid catalysts include strong acids such as strong mineral acids (e.g., sulfuric acid, phosphoric acid and / or hydrochloric acid) as well as strong organic acid catalysts such as oxalic acid, p-toluene sulfonic acid, and inorganic salts such as since acetate, zine borate, and the like. Such functionalization reactions may occur at temperature of about 50 to about 100°C, preferably, about 55 to about 90°C, and most preferably, about 60 to about 85°C.

[0058] In embodiments or approaches, examples of a functionalized novolac -type resin (e.g., the first resin reacted using the reactive solvent including the dialkoxymethane) is a resin (e.g., a polymer or an oligomer) having the general structure of the below Formulas Ila or lib (however, the structures of Formula II below are not generalized structures of all functionalized novolac-type resins herein, but merely examples):(Formula Ila) (Formula lib) wherein the polymer or oligomer, in one approach, has a polymer backbone with repeating aromatic groups having alkylene bridging (preferably methylene) therebetween or, in another approach, a polymer backbone with carbon-carbon double bonds and wherein each embodiments includes aromatic groups thereof with protected substituent groups, such as protected substituent methylol groups, and most preferably, the substituent methylol groups include an alkoxymethylene substituent (e.g., the -CH2OR4 groups) (and wherein such protected groups may only be present, in one embodiment, as an intermediate reaction product that is further used during curing reactions). In one approach, the substituent methylol groups as shown in Formula II above include the R4 groups being a Cl to CIO alkyl group or a Cl to CIO alkylether group (e.g., an alkyl group having one or more carbon atoms replaced with an oxygen atom). Preferably, the R4 groups include a Cl to C6 alkyl group, more preferably, a C2 to C5 alky l group, and most preferably, a C4 alkyl group. In preferred embodiments, the functionalized novolac resins herein have a number average molecular weight greater than about 500 g / mol, preferably, greater than about 750 g / mol, and most preferably greater than 1,000 g / mol. In other embodiments, the functionalized novolac resins herein having a number average molecular weight less than about 4,000 g / mol, preferably less than about 3,500 g / mol, and more preferably less than 3,000 g / mol. Number average molecular weight as used herein is measured by gel permeation chromotagraphy (GPC) using polystyrene standards.

[0059] More specifically and in one embodiment, the formed functionalized novolac-type resins herein are resins (e.g., polymers or oligomers) having a main backbone including hydrocarbyl-bridged aromatic groups with the alkoxymethylene substituents when formed from the conventional novolac starting reactant. In one approach, the reactants have a molar ratio of the dialkoxymethane to the conventional novolac resin (e.g., Dialkoxymethane tonovolac ratio) of at least about 0.07, in other approaches, at least about 0.2, in yet other approaches, at least about 0.4, and in yet further approaches, at least about 0.6. In one approach, the hydrocarbyl-bridge or link between adjacent aromatic groups in the main backbone chain is preferably a methylene group as shown above for Formula II. Most preferably in such embodiment, the backbone is substantially free of ether bridges between aromatic groups.

[0060] In embodiments, the methylol or methylol ether group of Formula II above is attached at either the ortho- or the para- position of the phenolic ring and, most preferably, at as shown above in Formula II at the / wra-position of the phenolic ring (all relative to the hydroxy group). As appreciated by those of ordinary skill, methylol substitution on the phenolic ring can be determined via 13C NMR and the like analytical techniques.

[0061] In embodiments, the substituent methylol groups include an alkoxymethylene substituent (e.g., an -CH2OR4 groups). In one approach, the substituent methylol groups (e.g., the protected substituent methylol groups) include the R4 groups being a Cl to C 10 alkyd group or a Cl to CIO alkylether group (e.g., an alky l group having one or more carbon atoms replaced with an oxygen atom). Preferably, the R4 groups include a Cl to C6 alkyl group, more preferably, a C2 to C5 alkyl group, and most preferably, a C4 alk l group. In some approaches, the protected substituent methylol group can be formed in situ during coating cure.

[0062] In embodiments, the functionalized novolac resin herein is stable at room temperature (e.g., about 20°C to about 25°C) for at least about 90 days with stability reflecting a minimal change in viscosity7of the functionalized novolac resin being less than a 100 percent viscosity increase relative to the viscosity at time TO, and preferably, a change in viscosity of about 0 to less than 50 percent viscosity increase relative to the viscosity at time TO with viscosity measured by ASTM D2983 (e.g., spindle selection and rpm).

[0063] In embodiments, the novolac resins herein are prepared with a molar ratio of the dialkoxymethane component to the conventional novolac resin component (e.g., dialkoxymethane / novolac) of at least about 0.07. in other approaches, at least about 0.2, in yet other approaches, at least about 0.4, and in yet further approaches, at least about 0.6. In other embodiments, the novolac resins may separately, and optionally, include one or moreoptional monomers or monomer units, including but not limited to ethylenically unsaturated monomers, such as, for example, (meth)acrylates (e.g., alkyl, cycloalkyl, alkoxy, and aromatic (meth)acrylates), vinyl esters of saturated carboxylic acids, monoolefms, conjugated dienes, styrene, (meth)acrylamide, methylol (meth)acrylamide, styrene, a-methyl styrene, vinyl toluene, vinyl propionate, vinyl acetate, acrylonitrile, vinyl chloride (the use of halogencontaining monomers is not presently preferred), and the like. In an embodiment, the other monomers may include one or more polyfunctional (meth)acrylate monomers. In some embodiments, the other monomers also include one or more ethylenically unsaturated carboxy-functional amide monomers, e.g., ureido-functional monomers, such as monomers formed as the product of the reaction between aminoalkyl alkylene urea (e.g., amino ethylene urea, for example) with an ethylenically unsaturated carboxylic acid or anhydride (e.g., maleic anhydride, for example). Examples of suitable (meth)acrylate and (meth)acrylic monomers include acrylic acid, methacrylic acid, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, benzyl acr late, methyl methacrylate, ethyl methacrylate, propyl methacry late, butyl methacrylate, 2-ethylhexyl methacrylate, hydroxyethyl acrylate, hydroxy ethyl methacrylate, hydroxybutyl acrylate, hydroxybutyl methacrylate, cyclohexyl methacrylate (CHMA), glycidyl methacrylate, 4- hydroxybutyl acry late glycidyl ether, allyl methacrylate, and mixtures thereof. Preferred optional monomers include styrene, methyl methacrylate, ethyl acrylate, methacrylic acid, n- butyl acrylate, tert-butyl acry late, tert-butyl methacrylate, n-butyl methacrylate, esters of itaconic acid, vinyl acetate, 2-ethyl hexyl acrylate, CHMA, bio-based monomers, and the tike. Suitable multi-ethylenically unsaturated monomers include polyfunctional acry lates such as, for example, di-, tri- and tetra-functional acrylates.

[0064] In further embodiments, the optional, other monomers may further include one or more bio-based monomers. ‘‘Bio-based,’’ as used wi th respect to monomers herein, refers to monomers that are preferably obtained from bio-renewable, ethylenically unsaturated monomers. Such bio-renewable ethylenically unsaturated monomers have a carbon-14 (C-14) content that is significantly higher than ethylenically unsaturated monomers derived from fossil fuels. C-14 has a relatively short half-life on the scale of the age of fossil-fuel-based materials, and so is present in lower amounts in fossil-fuel-based materials relative to biobased materials. Thus, “bio-renewable” ethylenically unsaturated monomers as used hereinmean monomers for which the level of C-14 isotope is comparable to the mean level of C-14 in atmospheric CO2, as measured by ASTM D6866 or having at least about 1.5 dpm / gC (disintegrations per minute per gram carbon), at least 2.5 dpm / gC, or at least 3.0 dpm / gC of C-14, as measured through liquid scintillation counting. Exemplary such bio-based monomers include esters of itaconic acid, bio-derived (meth)acrylic acid or its ester, and alkyl (meth)acrylic acid or its ester. In embodiments, bio-based monomers make up at least 10 wt %. at least 20 wt %. at least 30 wt %, or at least 40 wt % of the vinyl resole phenolic resin by weight of all monomers polymerized to form the vinyl resole phenolic resin.

[0065] Monomer constituent units need not be arranged in the self-crosslinking novolac resins herein in any particular order. The monomers of the novolac resins may be polymerized such that the monomer constituent units are randomly distributed throughout (forming a statistical copolymer), in segmented or repeating blocks (block copolymer) or in other arrangements.

[0066] Optional Liquid Carrier:

[0067] In some embodiments, the food or beverage container coating compositions herein further include an optional water-based or organic-solvent-based liquid carrier. In preferred embodiments, the carrier is a liquid solvent that is capable of dissolving or dispersing the first resin and / or the second polymer. In further preferred embodiments, the solvent is a protic solvent such as alcohols (e.g., butanol, carbitol) and glycols, cyclic or non-cyclic ethers such as tetrahydrofuran (THF), di(propylene glycol) dimethyl ether, or a mixture of isomers (for example, isomers of ether solvents as in CAS No. 111109-77-4), or mixtures thereof. In embodiments, the carrier liquid may include water. In some embodiments, the coating composition is an aqueous coating composition, which may optionally include one or more water-miscible organic solvents. In other embodiments, the coating composition is an organic-solvent based coating composition that is substantially non-aqueous (e.g., less than 0.2 weight percent water, less than 0.1 weight percent water, or less than 0.05 weight percent water).

[0068] In preferred embodiments, the self-crosslinking novolac resin and / or the food or beverage container coating compositions herein are substantially free, more preferably essentially free, more preferably essentially completely free, and optionally completely free of each of or at least one of formaldehyde (i.e., free formaldehyde), phenols (i.e., free phenols), bisphenol A (“BP A’"), bisphenol F (“BPF”), bisphenol S (“BPS”), and epoxides of BP A. BPF. and BPS. In certain preferred embodiments, the self-crosslinking novolac resin do not contain any BPA. BPF. BPS. or epoxides of BP A, BPF, and BPS. In preferred embodiments, the monomer components used to make the self-crosslinking novolac resins herein do not include glycidyl acry late or glycidyl methacry late. In some embodiments, the self-crosslinking novolac resin does not include any oxirane functionality. In yet other approaches, the self-crosslinking novolac resin is preferably not made using any halogenated monomers (e.g., vinyl chloride). More preferably, the self-crosslinking novolac resin does not include any halogen atoms.

[0069] Second Polymer

[0070] The food or beverage container coating compositions herein may further include a second polymer capable of participating in a cross-linking reaction with the self-crosslinking novolac-type resins herein without the need for conventional novolac curing agents (e.g., substantially free of conventional curing agents as discussed above). That is, crosslinking may occur solely with the application of heating or baking, such as a temperature of about 130 to about 200°C, or about 175 to about 220°C, or preferably 180 to about 250°C.

[0071] A wide variety of second polymers ty pically used in the container coating industrycan be used in the compositions of the present disclosure. These include, for example, a poly ether polymer, a polyester polymer (including, e.g., polyester urethanes), an acry lic polymer, a polyolefin polymer, a copolymer thereof having hydroxy groups (preferably, primary' hydroxy groups) and / or carboxylic groups for reacting with the self-crosslinking novolac-type resin, and / or combinations thereof (including copolymers thereof such as polyether-acrylics). The second polymer is preferably not made using bisphenol A, bisphenol F, and bisphenol S or any reactants derived therefrom (e.g., the diglycidyl ether of bisphenol A “BADGE”). In some embodiments, the second polymer is not made using any bisphenols or any reactants derived therefrom.

[0072] In certain embodiments, the second polymer has a molecular weight (number average) of at least 2,000 g / mol, at least 3,000 g / mol. or at least 4,000 g / mol. In certain embodiments, the second polymer has a molecular weight (number average) of up to 20,000 g / mol, up to 10,000 g / mol, or up to 7,000 g / mol. The number-average molecular weight can be determined by gel permeation chromatography (GPC) and polystyrene standards. In other approaches, the second polymer has an acid number of at least about 0 mg KOH / g resin, and preferably, about 0 to about 150 mg KOH / g resin. The second polymer may also have a hydroxyl number of at least about 15 mg KOH / g resin, and preferably, about 20 to about 200 mg KOH / g resin. In some embodiments, the second polymers has a glass transition temperature (Tg) of greater than 70°C, greater than 80°C, greater than 90°C, or greater than 100°C, and in some approaches, less than 150°C, less than 140°C, less than 120°C, or less than 110°C.

[0073] Examples of suitable polyether second polymers for use in coating compositions of the present disclosure include those that contain a plurality of aromatic ether segments. The poly ether polymer may be formed, for example, from reactants including a polyhydric phenol group-containing compound (more typically a dihydric phenol group-containing compound) and a polyepoxide, which may be an aliphatic polyepoxide or a poly epoxide a polyhydric phenol group-containing compound (more typically a diepoxide of a dihydric phenol group- containing compound). Such poly ether second polymers may include one or more segments having one or more optionally substituted aryl or heteroaryl groups in a backbone portion of the segment. In some embodiments, the one or more such aryl or heteroaryl groups include one or more substituent groups (preferably “bulky” substituent groups) that are attached to the ring preferably at an ortho or meta position, more preferably an ortho position, relative to an oxygen atom attached to the ring, which is typically an oxygen atom of an ether or ester linkage, more typically an ether linkage. In some embodiments, the one or more segments include two or more aryl or heteroaryl groups in which at least two of the aryl or heteroaryl groups include an oxygen atom attached to the ring and a substituent group (preferably a “bulky” substituent group) attached to the ring preferably at an ortho or meta position relative to the oxygen atom. Non-limiting examples of such materials having ortho substituent groups include tetramethyl bisphenol F (TMBPF), di epoxides of TMBPF, and polymers formedtherefrom. Examples of suitable such polymers are described in U.S. Pat. Pub. No. 2013 / 0316109 (Niederst et al.), herein incorporated by reference in its entirety.

[0074] In certain embodiments, the second polymer is a polyether (e.g., an aromatic poly ether). In certain embodiments, the polyether second polymer has a glass transition temperature (Tg) of greater than 70°C. or greater than 80°C. In certain embodiments, the poly ether second polymer has a Tg of up to 150°C, or up to 110°C. In certain embodiments, the poly ether second polymer is made from the reaction of a diepoxide of an ortho-substituted diphenol group-containing compound (e.g., the diglycidyl ether of tetra-methyl-bisphenol F) with an extender (e.g., a diphenol group-containing compound such as hydroquinone, or a diacid). Examples of suitable such polymers are described in U.S. Pat. Pub. No. 2013 / 0316109 (Niederst et al ). Examples of suitable polyether polymers (BPA free) are disclosed in U.S. Pat. No. 9,409,219 (Niederst et al.), U.S. Pat. Pub. No. 2013 / 0206756 (Niederst et al.), U.S. Pat. Pub. No. 2015 / 0021323 (Niederst et al.), International Pub. Nos. WO 2015 / 160788 (Valspar Sourcing). WO 2015 / 164703 (Valspar Sourcing). WO 2015 / 057932 (Valspar Sourcing), and WO 2015 / 179064 (Valspar Sourcing), each incorporated herein by reference in their entirety.

[0075] Examples of commercially available polyester second polymers that are suitable for use in coating compositions of the present disclosure include saturated polyesters available under the trade names DYNAPOL L, LH, and LS (Degussa AG, 45764 Marl, Germany), amorphous copolyesters available under the trade names VYLON GK330 and GK640 (Toyobo Co. Ltd., Osaka 530-8230, Japan), saturated thermoplastic polyesters available under the trade names SYNOLAC 75 NA 64 (medium molecular weight) and SYNOLAC 0691 S 60 (high molecular weight) (both available from Cray Valley, F-92091 Paris La Defense Cedex, France), alkyd type polyester resins, for example, those commercially available under the trade names URALAC AN621 S-2 60 and URALAC AN637 S-2 60 (available from DSM Neoresins BV, 5140 AC Waalwijk. Netherlands), and other polyesters available under the trade names DESMOPHEN T 1 65 SN / IB and RUCOTE 552 (both available from Bayer Material Science AG, D-51368, Leverkusen, Germany) as well as URALAC SN800 S2G3-60, URALAC SN852 S2F-60, and URALAC SN859 S2G3-50 (all available from DSM Neoresins BV, 5140 AC Waalwijk, Netherlands). Other suitable polyester second polymers are described in U.S. Pat. Nos. 8,367,171, 8,574,672, 8,449,960,9,096,772, 9,187,213, 9,650,176, and 11,827,803 and U.S. Publ. No. 2020 / 0263053, which are incorporated herein by reference.

[0076] Acrylic second polymers that are suitable for use in coating compositions of the present disclosure include the reaction products of a composition that includes a (meth)acrylic acid ester, an ethylenically unsaturated mono- or multi-functional acid, and an optional vinyl compound. For example, the acrylate second polymer could be a reaction product of components that include ethyl acrylate, acrylic acid, and styrene (preferably in the presence of 2,2’-azobis(2-methyl-butyronitrile) and tert-buty l peroxybenzoate free radical initiators).

[0077] Examples of suitable (meth)acrylic acid esters (i.e., methacrylic acid esters and acrylic acid esters) include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate. pentyl (meth)acrylate. isoamyl (meth)acrylate, hexyl (meth)acrylate. 2-hy dr oxy ethyl (meth)acr late. 2-ethylhexyl (meth)acrylate, cyclohexyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, benzyd (meth)acrylate, 2-hydroxypropyl (meth)acry late, laury l (meth)acry ate, isobomyl (meth)acrylate, octyl (meth)acrylate, and nonyl (meth)acrylate. Examples of suitable ethylenically unsaturated mono- or multi-functional acids include methacrylic acid, acrylic acid, crotonic acid, itaconic acid, maleic acid, mesaconic acid, citraconic acid, sorbic acid, and fumaric acid.Examples of suitable vinyl compounds include styrene, halostyrene, isoprene, a conjugated butadiene, alpha-methylstyrene, vinyl toluene, vinyl naphthalene, vinyl chloride, acrylonitrile, methacrylonitrile, vinyl acetate, vinyl propionate, vinyl cyclohexane, vinyl cyclooctane, vinyl cyclohexene, and vinyl stearate.

[0078] Examples of commercially available acrylic second polymers that are suitable for use in coating compositions of the present disclosure include those available under the trade names VIACRYL SC 454 / 50BSNB, VIACRYL SC383w / 50WA, and VANCRYL 2900 DEV (all from Cytec Industries Inc., West Patterson, NJ), as well as NEOCRYL A-639, NEOCRYL XK-64, URACON CR203 M3, and URACON CS113 SIG (all from DSM Neoresins BV, 5140 AC Waalwijk, Netherlands). Examples of acrylic second polymers can be found in U.S. Pat. No. 7,592,047 (O’Brien), U.S. Pat. No. 7,189,787 (O’Brien), U.S. Pat.No. 8,168,276 (Cleaver et al ), U.S. Pat. No. 9,181,448 (Li et al.). U.S. Pat. No. 9,394,456 (Rademacher et al.), U.S. Pat. Pub. No 2016 / 0009941 (Rademacher et al.), U.S. Pat. Pub. No. US2016 / 0376446 (Gibanel et al.), U.S. Pat. Pub. No. 2017 / 0002227 (Gibanel et al.), U.S. Pat. Pub. No. 2018 / 0265729 (Gibanel et al.), WO2016 / 196174 (Singer et al.), W02016 / 196190 (Singer et al.), WO2017 / 112837 (Gibanel et al.), WO2017 / 180895 (O’Brien et. al.), W02018 / 085052 (Gibanel et al.), WO2018 / 075762 (Gibanel et al.), WO2019 / 078925 (Gibanel et al.),W02019 / 046700 (O’Brien et al.), and W02019 / 046750 (O’Brien et al.), each incorporated herein by reference in their entirety.

[0079] Examples of suitable polyolefin second polymers for use in coating compositions of the present disclosure include maleic-modified polyethylene, maleic-modified polypropylene, ethylene acrylic acid copolymers, ethylene methacrylic acid copolymers, propylene acrylic acid copolymers, propylene methacrylic acid copolymers, and ethylene vinyl alcohol copolymers.

[0080] Examples of commercially available polyolefin second polymers that are suitable for use in coating compositions of the present disclosure include those available under the trade names DOW PRIMACOR 59801, DUPONT NUCREL, POLYBOND 1103, NIPPON SOARNOL (EV OH), ARKEMA OREVAC 18751, and ARKEMA OREVAC 18360. Examples of polyolefin second polymers can be found in U.S. Pat. No. 9,000,074 (Choudhery), U.S. Pat. No. 8,791,204 (Choudhery), and International Pub. No. WO 2014 / 140057 (Akzo Nobel) and U.S. Pat. No. 8,722,787 (Romick et al.), U.S. Pat. No. 8,779,053 (Lundgard et al.), and U.S. Pat. No. 8,946,329 (Wilbur et al.), each incorporated herein by reference in their entirety.

[0081] For aqueous coating compositions, preferred second polymers are polyether- acry lic second polymers, wherein the acrylate (i.e., aciyiic) portion provides water- dispersing groups. In certain embodiments, the polyether-acrylic polymers are latex polymers.Examples of such latexes are described, e.g., in WO2017 / 180895 (O’Brien et. al.) and International App. No. W02019046700 (O’Brien et al.), each incorporated herein by reference in their entirety'.

[0082] Food or Beverage Container Coating Compositions

[0083] In another aspect, the invention is a food or beverage container coating composition that includes (a) the first resin and / or functionalized first resin as described according to any embodiment herein combined with (b) the second polymer discussed above, (c) reactive solvent, which in some embodiments may be pre-reacted with the first resin prior to preparation of the coating composition, and (d) optionally a water-based or a solvent-based liquid carrier. The food or beverage container coating compositions herein preferably include an excess of the second polymer, on a weight basis, relative to the self-crosslinking novolac- type resin. While non-food-contact coating compositions are within the scope of this invention, preferred coating compositions are packaging coating compositions suitable for use as food-contact coatings. The coating compositions may also include a catalyst (such as, e.g., an acid catalyst) to enhance curing and / or crosslinking. The coating composition may further include optional additional polymers, optional other hydroxyl-reactive and / or carboxyl-reactive crosslinkers, and optional additional components. Although liquid carrierbased coating compositions are preferred, it is contemplated that the coating compositions of the invention may have utility in other coating application techniques such as, for example, powder coating, extrusion coating, or lamination. Preferred cured coatings of the invention exhibit a suitable balance of coating properties, including excellent chemical resistance, excellent fabrication properties, and good adhesion.

[0084] Coating compositions of the present disclosure may include any suitable amount of the the first resin and / or functionalized first resin to produce the desired result. In preferred embodiments, the preferred food or beverage container coating compositions herein include at least about 1 weight percent of the first resin and / or functionalized first resin, in further embodiments, at least about 5 weight percent, in further embodiments, at least about 10 weight percent, in still further embodiments, at least about 15 weight percent, and in still further embodiments, at least about 20 weight percent of the first resin and / or functionalized first resin, wherein w eight percent is expressed as the nonvolatile first resin and / or functionalized first resin content weight as a percentage of total resin solids. Preferably, the coating compositions herein include at most about 75 w eight percent of the first resin and / or functionalized first resin, in further embodiments, at most about 50 w eight percent, in further embodiments, at most about 40 weight percent, in still further embodiments, at most about 30 weight percent, and in still further embodiments, at most about 20 weight percent, whereagain weight percent is expressed as the nonvolatile the first resin and / or functionalized first resin content weight as a percentage of total resin solids weight. In certain embodiments, the first resin and / or functionalized first resin may optionally be present in an amount of 100 weight percent, and in such optional context, there is no distinct second polymer as discussed herein. In such optional embodiments, the self-crosslinking novolac-type resin is both the film-former and the crosslinker (i.e.. it self-crosslinks with itself).

[0085] Coating compositions of the present disclosure may include any suitable amount of second polymer to produce the desired result and, preferably, the composition includes an excess of the second polymer, on a weight basis relative to the first resin and / or functionalized first resin. In some optional embodiments, the coating compositions herein do not include any second polymer, and the first resin and / or functionalized first resin is present to the exclusion of the second polymer. In preferred embodiments, the food or beverage container coating compositions herein include at least about 50 about w eight percent of the second polymer, in further embodiments, at least about 60 weight percent, in further embodiments, at least about 70 weight percent, in still further embodiments, at least about 75 weight percent, and in still further embodiments, at least about 80 weight percent, wherein weight percent is expressed as the nonvolatile second polymer content weight (which may optionally comprise two or more different second polymers) as a percentage of total resin solids. Preferably, the inventive coating compositions include at most about 99 weight percent of the second polymer, at most about 95 weight percent of the second polymer, at most about 90 w eight percent of the second polymer, in further embodiments, at most about 85 weight percent, in further embodiments, at most about 70 weight percent, in still further embodiments, at most about 65 weight percent, and in still further embodiments, at most about 60 weight percent, wherein again, weight percent is expressed as the nonvolatile second polymer content w eight as a percentage of total resin solids. In one particular embodiment, the food or beverage container coating composition includes about 5 to about 50 weight percent of the first resin and / or functionalized first resin (preferably, about 15 to about 35 weight percent of the self-crosslinking novolac resin) and about 50 to about 95 weight percent of the second resin (preferably, about 60 to about 80 weight percent of the second resin), based on total resin solids.

[0086] Preferred coating compositions of the invention preferably include less than 10,000 ppm, more preferably less than 1000 ppm. even more preferably less than about 500 ppm, or most preferably less than 100 ppm or in alternative embodiments are, more preferably substantially free, more preferably essentially free, even more preferably essentially completely free, and optimally completely free of each of or at least one of unreacted formaldehyde or phenols. In certain preferred embodiments, coating compositions of the present disclosure are preferably substantially free, more preferably essentially free, even more preferably essentially completely free, and optimally completely free of BP A, BPF, BPS, and epoxides of BP A, BPS, and BPF. To determine formaldehyde content herein, the procedures of EN ISO 9397 are followed.

[0087] When present, the concentration of one or more optional, additional crosslinkers may vary depending upon the desired result. For example, in some embodiments, the coating compositions may contain from about 0.01 weight percent to about 40 weight percent, more preferably from about 0.5 weight percent to about 35 weight percent, or even more preferably from about 3 weight percent to about 30 weight percent of one or more additional crosslinkers, by weight oftotal resin solids in the coating composition.

[0088] Any suitable optional, additional crosslinker can be used. For example, amino crosslinkers (e.g., aminoplasts), blocked isocyanate crosslinkers, a beta-hydroxyalkylamide crosslinker, a carbodiimide crosslinker, materials including oxirane groups (e.g., oxirane- functional polyester such as glycidyl-modified polyesters or oxirane-functional vinyl polymers such as acrylic resins formed using glycidyl methacrylate) and combinations thereof, may be used.

[0089] The coating compositions may optionally include amino crosslinker resins (e.g., aminoplasts). Amino crosslinker resins are typically the condensation products of aldehydes (e.g.. such as formaldehyde, acetaldehyde, crotonaldehyde, and benzaldehyde) with ammo- or amido-group-containing substances (e g., urea, melamine and benzoguanamine). Suitable amino crosslinking resins include, for example, benzoguanamine-formaldehyde-based resins, melamine-formaldehyde-based resins (e.g., hexamethonymethyl melamine), etherified melamine-formaldehyde, urea-formaldehyde-based resins, and mixtures thereof.

[0090] Condensation products of other amines and amides can also be employed such as, for example, aldehyde condensates of triazines, diazines, triazoles, guanadines, guanamines and alkyl- and aryl-substituted melamines. Some examples of such compounds are N,N’- dimethyl urea, benzourea, dicyandimide, formaguanamine, acetoguanamine, glycoluril, ammelin 2-chloro-4,6-diamino-l,3,5-triazine, 6-methyl-2,4-diamino-l,3,5-triazine, 3,5- diaminotriazole, triaminopyrimidine, 2-mercapto-4,6-diaminopyrimidine, 3,4,6- tris(ethylamino)-1.3.5-triazine, and the like. While the aldehyde employed is typically formaldehyde, other similar condensation products can be made from other aldehydes, such as acetaldehyde, crotonaldehyde, acrolein, benzaldehyde, furfural, glyoxal and the like, and mixtures thereof.

[0091] Suitable commercially available amino crosslinking resins include, for example, CYMEL 301, CYMEL 303, CYMEL 370, CYMEL 373, CYMEL 1131, CYMEL 1125, and CYMEL 5010 Maprenal MF 980 (all available from Cytec Industries Inc., West Patterson, NJ) and Uramex BF 892 (available from DSM, Netherlands).

[0092] Non-limiting examples of blocked isocyanate crosslinkers include aliphatic and / or cycloaliphatic blocked polyisocyanates such as HDI (hexamethylene diisocyanate), IPDI (isophorone diisocyanate). TMXDI (bis[4-isocyanatocyclohexyl]methane). HnMDI (tetramethylene-m-xylidene diisocyanate), TMI (isopropenyldimethyl-benzylisocyanate) and dimers or trimers thereof. Suitable blocking agents include, for example, n-butanone oxime, 8-caprolactam, diethyl malonate. and secondary amines. Non-limiting examples of suitable commercially available blocked isocyanate crosslinkers include VESTANAT B 1358 A, VESTANAT EP B 1 186 A, VESTANA EP B 1299 SV (all available from Degussa Corp.. Marl, Germany); and DESMODUR VPLS 2078 and DESMODURBL 3175 (available from Bayer A.G., Leverkusen, Germany). In some embodiments, blocked isocyanates may be used that have an Mn of at least about 300, more preferably at least about 650, and even more preferably at least about 1.000.

[0093] One preferred optional ingredient is a catalyst to increase the rate of cure and / or the extent of crosslinking. The catalyst is ty pically chosen from among the catalysts known for use in the crosslinking of resole type phenolic resin and / or the electrophilic substitution of aromatic rings. Examples of such catalysts, include but are not limited to, strong acids (e g.,dodecylbenzene sulphonic acid (DDBSA), available as CYCAT 600 from Cytec), methane sulfonic acid (MSA), p-toluene sulfonic acid (pTS A), dinonylnaphthalene disulfonic acid (DNNDSA), sulfuric acid, triflic acid, phosphoric acid, and mixtures thereof and bases (e.g., dimethylethanolamine, l,5-diazabicyclo(4,3,0)non-5-ene (“DBN”), 1,5-diazabicyclo (4,3,0) non-7-ene (“DBU’'), and NaOH).

[0094] The coating compositions of the present disclosure are presently preferred for food or beverage coating applications and, in particular, food-contact coatings. While not intending to be bound by any theory7, cured packaging coatings formulated using the first resin and / or functionalized first resin of the present disclosure (with or without optional additional polymers, other components, or crosslinkers such as, e.g.. aminoplasts and / or blocked isocyanate) have been observed to exhibit superior coating properties (e g., superior chemical resistance) relative to comparable coating compositions formulated with other ty pes of crosslinker(s) (e.g., amino and / or blocked isocyanate alone without vinyl resole phenolic-ty pe crosslinkers) or conventional polymer / resole crosslinker systems. In preferred embodiments, the self-crosslinking novolac-type resins (after formation) is also believed to form covalent bonds with suitable functional groups on the second polymer such as hydroxyl groups during cure (e.g., thermal cure) of the coating composition to form a cured coating, resulting in the formation of a crosslinked polymer network including both the self-crosslinking novolac-type resins and the second polymer.

[0095] If used, a catalyst is preferably present in an amount of at least 0.01 weight percent, and more preferably at least 0.1 weight percent, based on the weight of nonvolatile material. If used, a catalyst is preferably present in an amount of no greater than 3 weight percent, and more preferably no greater than 1 weight percent, based on the weight of nonvolatile material.

[0096] If desired, coating compositions of the present disclosure may optionally include other additives that do not adversely^ affect the coating composition or a cured coating resulting therefrom. Suitable additives include, for example, those that improve the processability7or manufacturability7of the composition, enhance composition aesthetics, or improve a particular functional property or characteristic of the coating composition or the cured composition resulting therefrom, such as adhesion to a substrate. Additives that may beincluded are carriers, additional polymers, emulsifiers, pigments, metal powders or paste, fillers, anti -migration aids, anti-microbials, extenders, curing agents, lubricants, coalescents, wetting agents, biocides, plasticizers, crosslinking agents, antifoaming agents, colorants, waxes, anti-oxidants, anticorrosion agents, flow control agents, thixotropic agents, dispersants, adhesion promoters, UV stabilizers, scavenger agents or combinations thereof. Each optional ingredient can be included in a sufficient amount to serve its intended purpose, but preferably not in such an amount to adversely affect a coating composition or a cured coating resulting therefrom.

[0097] In some embodiments, the coating compositions herein may be a water-based varnish. In some such embodiments, preferably the coating compositions include at least about 50 weight percent total volatiles, more preferably at least about 60 weight percent total volatiles, and even more preferably at least about 75 weight percent is total volatiles. Certain coating compositions of the invention include at least about 10 weight percent total volatiles, more preferably at least about 20 weight percent of total volatiles, and even more preferably at least about 40 weight percent of total volatiles (in some embodiments about 50 weight percent or more of total volatiles), based on the total weight of the coating composition.

[0098] Food or beverage container coating compositions of the present disclosure may be prepared by conventional methods in various ways. For example, the coating compositions may be prepared by simply admixing the first resin and / or functionalized first resin and a second polymer, and any other optional ingredients, in any desired order, with sufficient agitation. The resulting mixture may be admixed until all the composition ingredients are substantially homogeneously blended. Alternatively, the coating compositions may be prepared as a liquid solution or dispersion by admixing an optional carrier liquid, the first resin and / or functionalized first resin or the first resin and / or functionalized first resin and the second polymer, and any other optional ingredients, in any desired order, with sufficient agitation. An additional amount of carrier liquid may be added to the coating compositions to adjust the amount of nonvolatile material in the coating composition to a desired level.

[0099] The total amount of solids present in coating compositions herein may vary depending upon a variety of factors including, for example, the desired method of application. Presently preferred coating compositions include at least about 18, at least about 19, at least about 20,at least about 30, at least about 35, or at least about 40 wt % of solids, based on the total weight of the coating composition. Preferably, the coating compositions include less than about 80, more preferably less than about 70, and even more preferably less than about 65 wt % of solids, based on the total weight of the coating composition.

[0100] In another embodiment, the present disclosure provides a coating composition that includes the first resin and / or functionalized first resin in combination with an optional thermoplastic dispersion and optional other components. Such coating compositions may be suitable for various applications such as, for example, food or beverage packaging applications. While not intending to be bound by any theory, it is believed that certain selfcrosslinking novolac resins and second polymer combinations herein are capable of stabilizing certain thermoplastic materials such as, for example, poly vinyl chloride (“PVC”) to prevent or decrease degradation of the thermoplastic material or a cured coating resulting therefrom. Thus, in optional embodiments, an efficacious amount of the self-crosslinking novolac resin and second polymer (e.g., for purposes of stabilizing the thermoplastic dispersion) in an organosol or plastisol coating composition. Organosols useful in the compositions herein, include, for example, vinyl organosols. A “vinyl organosol,” as used herein, includes dispersed polymer particles of vinyl chloride polymers (preferably high- molecular-weight vinyl chloride polymers) in a liquid carrier. A discussion of suitable materials and preparation methods for such compositions may be found, for example, in PCT / US2008 / 058899.

[0101] Organosol coating compositions herein may preferably include at least about 10. weight percent, more preferably at least about 15 weight percent, and even more preferably at least about 20 weight percent of the second polymer, based on the total nonvolatile weight of the coating composition. The organosol coating compositions preferably include less than about 90 weight percent, more preferably less than about 70 weight percent, and even more preferably less than about 60 weight percent of the second polymer, based on the total nonvolatile weight of the coating composition.

[0102] Organosol coating compositions of the invention preferably include at least about 10 weight percent, more preferably at least about 15 weight percent, and even more preferably at least about 20 weight percent of thermoplastic material, based on the totalnonvolatile weight of the coating composition. The organosol coating compositions preferably include less than about 80 weight percent, more preferably less than about 70 weight percent, and even more preferably less than about 65 weight percent of thermoplastic material, based on the total nonvolatile weight of the coating composition. The concentration of self-crosslinking novolac resin in the organosol coating compositions of the invention may vary depending upon the desired result.

[0103] Examples of suitable thermoplastic materials include halogenated polyolefins, which include, for example, copolymers and homopolymers of vinyl chloride, vinylidenefluoride, poly chloroprene, poly chloroisoprene, polychlorobutylene, and combinations thereof. PVC is a particularly preferred thermoplastic material. The thermoplastic material preferably has a number average molecular weight (Mn) of from about 40,000 g / mol to about 300,000 g / mol; more preferably from about 75,000 g / mol to about 200,000 g / mol: and even more preferably from about 100,000 g / mol to about 150,000 g / mol.

[0104] In applications involving packaging coatings, dispersion grade thermoplastic particles are preferred, where the particles range in size from greater than 0 to about 5 microns, based on volume-average median particle diameter. Other sizes, however, can be used such as. for example, non-dispersion grade thermoplastic particles that range in size from about 5 to about 100 microns, based on volume-average median particle diameter.

[0105] The thermoplastic material is preferably dispersed in a liquid carrier to fonn a thermoplastic dispersion. Examples of suitable liquid carriers include an organic solvent, a plasticizer, or mixtures thereof. Suitable organic solvents may include polar solvents such as ketones (e.g., MIBK and DIBK), glycol ethers, alcohols, aliphatic hydrocarbons, aromatic hydrocarbons, or mixtures thereof. In some embodiments, it may be advantageous to choose a solvent that has an affinity to the thermoplastic material and / or one that can swell the thermoplastic particles to facilitate storage stability of the liquid coating composition.Preferred liquid carriers exhibit sufficient volatility to substantially evaporate from the coating composition during the curing process.

[0106] Cured coatings of the invention preferably adhere well to metal (e.g., steel, tin- free steel (TFS), tin plate, electrolytic tin plate (ETP), aluminum, etc.) and provide high levels of resistance to corrosion or degradation that may be caused by prolonged exposure toproducts such as food or beverage products. The coatings may be applied to any suitable surface, including inside surfaces of containers, outside surfaces of containers, container ends, and combinations thereof.

[0107] The coating composition of the invention can be applied to a substrate using any suitable procedure such as spray coating, roll coating, coil coating, curtain coating, immersion coating, meniscus coating, kiss coating, blade coating, knife coating, dip coating, slot coating, slide coating, and the like, as well as other types of premetered coating. In one embodiment where the coating is used to coat metal sheets or coils, the coating can be applied by roll coating.

[0108] The coating composition can be applied on a substrate prior to, or after, forming the substrate into an article. In some embodiments, at least a portion of a planar substrate is coated with one or more layers of the coating composition of the invention, which is then cured before the substrate is formed into an article.

[0109] In certain embodiments, a food or beverage container coating composition of the present disclosure is thermally curable at a temperature of at least 176°C, or at least 190°C. In certain embodiments, a food or beverage container coating composition of the present disclosure is thermally curable at a temperature of up to 250°C, or up to 235°C.

[0110] In certain embodiments, a food or beverage container coating composition of the present disclosure is thermally curable in at least 10 seconds, at least 20 seconds, or in at least 30 seconds. In certain embodiments, a food or beverage container coating composition of the present disclosure is thermally curable within a period of up to 30 minutes, or up to 20 minutes, or up to 10 minutes, or up to 5 minutes.

[0111] After applying the coating composition onto a substrate, the composition can be cured using a variety of processes, including, for example, oven baking by either conventional or convectional methods. The curing process may be performed in either discrete or combined steps. For example, the coated substrate can be dried at ambient temperature to leave the coating composition in a largely un-crosslinked state. The coated substrate can then be heated to fully cure the coating composition. In certain instances, thecoating composition can be dried and cured in one step. In preferred embodiments, the coating composition of the invention is a heat-curable coating composition.

[0112] The curing process may be performed at any suitable temperature, including, for example, temperatures in the range of about 180°C to about 250°C. If metal coil is the substrate to be coated, curing of the applied coating composition may be conducted, for example, by subjecting the coated metal to a temperature of about 230°C to about 250°C for about 15 to 30 seconds. If metal sheeting is the substrate to be coated (e.g., such as used to make three-piece food cans), curing of the applied coating composition may be conducted, for example, by subjecting the coated metal to a temperature of about 190°C to about 210°C for about 3 to about 12 minutes (single bake).

[0113] The coating compositions of the present disclosure preferably have a viscosity (ASTM D2983) suitable for a given coating application. Although various application methods are useable, the coating compositions may have a viscosity suitable for spray coating. In further embodiments, the coating compositions have a viscosity of at least about 25 centipoise (cps) (25 mPas), in further embodiments at least about 50 mPas, in further embodiments at least about 150 mPas, in further embodiments at least about 500 mPas, and in still further embodiments, at least about 750 mPas. In further embodiments, the coating compositions have a viscosity of at most about 5000 mPas, in further embodiments at most about 4000 mPas, in further embodiments at most about 3000 mPas, and in still further embodiments, at most about 2000 mPas.

[0114] Coating compositions of the invention may be useful in a variety of coating applications. The coating compositions are particularly useful as adherent coatings on interior or exterior surfaces of metal containers. Examples of such articles include closures (including, e.g., internal surfaces of twist off caps for food and beverage containers); internal crowns; two- and three-piece cans (including, e.g., food and beverage containers); shallow drawn cans; deep drawn cans (including, e.g., multi-stage draw and redraw food cans); can ends (including, e.g., easy open can ends); monobloc aerosol containers; and general industrial containers, cans, and can ends.

[0115] The food or beverage container coating compositions herein may be suited for use on interior or exterior surfaces of metal food or beverage containers, including food-contact surfaces. In embodiments, the cured coatings are retortable when employed in food and beverage container applications. In embodiments, cured coatings of the compositions herein are capable of withstanding elevated temperature conditions frequently associated with retort processes or other food or beverage preservation or sterilization processes. Particularly preferred cured coatings exhibit enhanced resistance to such conditions while in contact with food or beverage products that exhibit one or more aggressive (or corrosive) chemical properties under such conditions. Examples of such aggressive food or beverage products may include meat-based products, milk-based products, fruit-based products, energy drinks, and acidic or acidified products.

[0116] In further embodiments, the food or beverage container coating compositions herein are suited for use on the surfaces of containers for household products, such as paint cans, aerosol containers, steel containers, and other containers.

[0117] In some embodiments, the food or beverage container coating compositions herein are suitable for use as a coating on the food-contact surface of the sidewall of a three- piece food can. The coating composition is typically applied to a metal sheet which is then typically cured prior to fabricating the coated sheet into the sidewall of a three-piece food can.

[0118] In some embodiments, the food or beverage container coating compositions herein are storage stable. As contemplated herein, a coating composition that is ‘‘storage stable” means that, when all components of the coating composition are mixed and stored prior to application to a substrate, the coatings compositions will retain their ability' during storage (for at least a certain amount of storage time) to be applied onto a substrate and then cure, following application. In preferred embodiments, the coating composition is storage stable for at least 20 days at ambient temperature, in further embodiments for at least one month, in further embodiments for at least 3 months, and in yet further embodiments for at least 6 months.

[0119] Use of the food or beverage container coating compositions herein include: providing a coating composition as descnbed herein; applying the coating composition to at least a portion of a metal substrate prior to or after forming the metal substrate into a food orbeverage container (e.g., a can) or portion thereof; and thermally curing the coating composition.

[0120] In certain embodiments of such methods, the metal substrate includes a steel or aluminum substrate. In certain embodiments of such methods, the coating composition is applied to a preformed food or beverage container or a portion thereof. That is. in certain embodiments, the metal substrate is in the form of a preformed food or beverage container having a sidewall and a bottom end, and spraying comprises spraying an interior surface of the sidewall and bottom end.

[0121] In certain embodiments of such methods, 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 container or a surface that will become an interior side of a food or beverage container). Thus, 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 food or beverage container after thermally curing the coating composition.

[0122] In certain embodiments of such methods, applying the coating composition includes applying the coating composition on the metal substrate in an amount sufficient to form a cured coating having an average dry film weight of 1 mg / in2(i.e., 1 .55 g / m2) to 20 mg / in2(i.e., 31 g / m2).

[0123] The disclosed food or beverage container coating compositions herein may be applied to a substrate either prior to, or after, the substrate is formed into an article such as, for example, a food or beverage container or a portion thereof. In one embodiment, a method of forming food or beverage containers is provided that includes: applying (via spray application, dipping, etc.) a coating composition described herein to a metal substrate (e.g., applying the composition to the metal substrate in the form of a planar coil or sheet), thermally curing the coating composition, and forming (e.g., via stamping) the substrate into a packaging container or a portion thereof (e.g., a food or beverage container or a portion thereof). For example, two-piece or three-piece cans or portions thereof such as riveted beverage can ends (e.g., soda or beer cans) with a cured coating of the disclosed coating composition on a surface thereof can be formed in such a method.

[0124] In other embodiments, the present disclosure also provides methods that include "causing" any embodiment of the food or beverage coating compositions herein to be used on a metal substrate (or portion thereof) of a metal food or beverage container or packaging. In some cases, where multiple parties are involved, a first party (e.g., the party7that manufactures and / or supplies the food or beverage container coating composition) may provide instructions, recommendations, or other disclosures about the food or beverage container coating composition end use to a second party (e.g.. a metal coater (e.g., a sheet coater for food bodies or food can ends), can maker, or brand owner). Such disclosures may7include, for example, instructions, recommendations, or other disclosures relating to coating a metal substrate for subsequent use in forming packaging containers or portions thereof, coating a metal substrate of pre-formed containers or portions thereof, preparing coating compositions for such uses, cure conditions or process-related conditions for such coatings, or suitable ty pes of packaged products for use with resulting coatings. Such disclosures may occur, for example, in technical data sheets (TDSs), safety7data sheets (SDSs), regulatory7disclosures, warranties or warranty limitation statements, marketing literature or presentations, or on company websites. A first party making such disclosures to a second party7shall be deemed to have ‘‘caused” any embodiment of the coating compositions herein to be used on a metal substrate of metal packaging (e.g., a container or closure) even if it is the second party that actually applies the composition to a metal substrate in commerce, uses such coated substrate in commerce on a metal substrate of packaging containers, and / or fills such coated containers with product.TEST METHODS

[0125] Unless indicated otherw ise, the following test methods w ere utilized in the Examples that follow;

[0126] Solvent Resistance Test (~‘MEK double rubs”)

[0127] The extent of “cure” or crosslinking of a coating w as measured as a resistance to solvents, such as methyl ethyl ketone (MEK). This test was performed as described in ASTM D 5402-93. The number of double rubs (i.e., one back-and-forth motion) until failure was reported. Preferably, the MEK solvent resistance was at least 30 double rubs (DR). Generally, high MEK rubs indicated high crosslink density which generally corresponded togood solvent (e.g., chemical) resistance. For example, coating films for food cans should be highly crosslinked (at least 30 double rubs, usually at least 50 double rubs) because many of food substances cause corrosion.

[0128] Adhesion Test

[0129] The Adhesion test was conducted according to ASTM D3359-17 using Scotch 610 type available from 3M (Saint Paul, MN). 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. IB, and 0B indicate that 0%, less than 5%, 5%-l 5%, 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, respectively. Preferably, an adhesion rating of at least 4B (i.e., 4B or 5B) is considered to be adherent.

[0130] Blush Resistance Test

[0131] Blush resistance measures the ability of a coating to resist attack by various solutions. Typically, blush is measured by the amount of water absorbed into a coated film. When the film absorbs water, it generally becomes cloudy or looks white. Blush was measured visually using a scale of 0-5 where a rating of “0” indicates no blush, a rating of “I’" indicates slight whitening of the film, and a rating of “3” indicates whitening of the film, and so on. Blush ratings of ”2" or less are typically desired for commercial packaging coatings and optimally ”1" or less.

[0132] Acid Number (AN) of Resin

[0133] The acid number (AN) of a resin may be measured by dissolving a suitable quantity of the resin in a solution of dimethyl formamide (DMF) and methyl ethyl ketone (MEK), then titrating with 0.1 N methanolic KOH and a cresol red / thymol blue or 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.

[0134] Hydroxyl Number of Resin

[0135] The hydroxyl value (HN) of a resin may be measured by dissolving a suitable quantity of the resin in Methylene Chloride before mixing the sample for 15-20 minutes with a 4-(dimethylamino) pyridine (DMAP) catalyst solution and a 97% acetic anhydride solution in anhydrous dimethyl formamide (DMF). A solution of DMF and deionized water is then added and the solution is mixed for an additional 15-20 minutes. After supplemental addition of tetrahydrofuran (THF), a titration method with 0.5 N methanolic KOH and a phenolphthalein indicator is used to measure the hydroxyl value of a resin. Based on the amount of KOH consumed as compared to titration of a solution without the resin, the hydroxyl value is calculated and reported as mg KOH per 1 g dry resin.

[0136] Viscosity (n)

[0137] Viscosity stability and / or apparent viscosity can be measured herein using a Brookfield viscometer. ASTM D2196-20 may be used to determine the apparent viscosity of any non-Newtonian materials. A suitable Brookfield Viscometer is model DV2T or equivalent (Brookfield Engineering Laboratories, Middleboro, MA). Apparent viscosity may be determined using Test Method A of ASTM D2196-20. Viscosity stability' or a stable viscosity refers to a composition with no more than a 50 percent viscosity increase in viscosity relative to the viscosity of the same composition at time TO. and preferably, a change in viscosity' of about 0 to less than 50 percent viscosity increase relative to the viscosity' at time TO. Viscosity stability' may also be measured on a Brookfield viscometer at room temperature and with the spindle size and rpm selected according to the parameters of ASTM D2983.

[0138] Reverse Impact Test

[0139] 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 one pound (0.45 kg) standard metal rod in a cylinder was dropped from a height of 36 inches (91.4 cm) onto the substrate (a BYK Gardner OVERBALL Bend and Impact Tester instrument was used). 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. A sample failed if crazing or cracks were observed. A sample passed if no crazing or cracks were observed.

[0140] Differential Scanning Calorimetry for Glass Transition Temperature (Tg)

[0141] Samples for differential scanning calorimetry (“DSC”) testing are prepared by first applying the liquid resin composition onto aluminum sheet panels. The panels are then baked in a Fisher Isotemp electric oven for 20 minutes at 300°F (149°C) to remove volatile materials. After cooling to room temperature, the samples are scraped from the panels, weighed into standard sample pans, and analyzed using the standard DSC heat-cool-heat method. The samples are equilibrated at -60°C, then heated at 20°C per minute to 200°C, cooled to -60°C, and then heated again at 20°C per minute to 200°C. Glass transition temperatures are calculated from the thermogram of the last heat cycle. The glass transition is measured at the inflection point of the transition.

[0142] Molecular Weight Determination by Gel Permeation Chromatography

[0143] Samples for Gel Permeation Chromatography (“GPC”) testing are prepared by first dissolving the liquid resin in THF. An aliquot of this solution is then analyzed by GPC along with mixtures of polystyrene (“PS”) standards and an epoxy control (Epon 1009F supplied by Hexion, Inc.). The molecular weights of the samples are calculated after processing the GPC runs and verifying the PS and Epon 1009F standards.

[0144] DMA Analysis

[0145] Dynamic mechanical properties and / or cure behavior of any samples herein was evaluated pursuant to ASTM D4473-08 (reapproved 2021) using an ARES G-2 rheometer (TA instruments) or the like and a rectangular torsion fixture (TA instruments) or the like with a modified temperature ramp and / or isothermal hold as described herein.

[0146] Sample preparation for each evaluation was the same and included a 1-inch strip of fiberglass support cloth along with two ' / 2-inch x 1-inch strips of aluminum foil. An 8” x 8” sheet of aluminum foil is placed in a fume hood as a workstation, with the strip of glass fiber placed atop it. A disposable transfer pipette is used to completely coat the top side of the cloth with the thermally curable material to be evaluated before flipping it over andcoating the reverse side. Forceps are used to drag the coated cloth along a clean area of the foil to remove excess coating from both sides and ensure an even distribution of material across the cloth. The strips of aluminum foil are folded to cover each end of the coated cloth strip to prevent material from curing on the grips of the torsion fixture. The sample is brought to the ARES-G2 and the aluminum-covered ends are loaded into the rectangular torsion fixture and secured hand-tight with an Allen wrench. The sample is manually put into 0.5 N of tension using the instrument controller and the instrument oven is closed around the sample. Next, the Temperature Ramp test aims to characterize the reaction onset temperature through identification of a sharp increase in storage modulus during a constant temperature ramp rate. The sample was equilibrated at 50°C for 30 seconds before instrument began increasing temperature at a constant rate of 5.0°C / min up to 300°C. The instrument maintained 0.5 N of tension and conducted strain-controlled torsional DMA measurements at 0. 1 % strain, 1 Hz and sampling 2 points / second throughout the test. The resulting data can be plotted with storage modulus [MPa] vs Temperature [C] in TA licensed data analysis software TRIOS [5],

[0147] If needed, the TRIOS’s “Onset Point” tool can be used to identify the reaction onset temperature within the temperature range where a sharp increase in storage modulus is observed after a prolonged period of constant storage modulus was measured. As the thermally curable material begins to cure on the support braid at the reaction onset temperature, the storage modulus of the sample significantly increases as new bonds are formed and the polymer network becomes more rigid and structured.

[0148] An Isothermal Hold test aims to characterize the reaction time constant “c” from an exponential fit of the storage modulus vs time curve as a sample is subjected to targeted cure conditions. After the sample was loaded into the instrument, the oven jumped to cure temperature of about 204.4°C (400°F) as quickly as possible (approximately 9.25°C / s) then held isothermal for 15 minutes while strain-controlled torsional DMA measurements were conducted at 0. 1 % strain, 1 Hz and 2 points / second were sampled throughout the test. If needed, a plot of storage modulus vs time can be analyzed in TRIOS [5] using the exponential fitting tool to fit the increase in storage modulus over time to an exponential equation and to determine fit parameters a, b, and c as show n in Equation 1.y = a + (b — a)(l — e c) (Equation 1) where y is storage modulus, a and b are fit parameters describing the modeled cured storage modulus value, x is time and c is the time constant. When time is equal to the time constant, Equation 1 approximates the storage modulus of the sample at 63% cure as shown below in Equation 2. when x = c e-1= 0.37(1 - 0.37) = 0.63 yx=c= a + (b — a)(0.63)yx=c= (Cured Modulus) (0.63) (Equation 2)Therefore, the time constant, c. is equal to the time for the sample to reach 63% cure. Given a set of samples tested under the DMA and oven conditions as described herein, the time constants can be compared to provide insight into which sample cures the fastest vs slowest in terms of time to 63% cure.EXAMPLES

[0149] The present disclosure is illustrated by the following Examples. It is to be understood that the particular examples, materials, amounts, and procedures are to be interpreted broadly in accordance with the scope and spirit of the inventions as set forth herein. Unless otherwise indicated in these Examples and throughout this disclosure, all parts, percentages, or ratios are by weight and all molecular weights are number average molecular weight. Unless otherwise specified, all chemicals used are commercially available from, for example, Sigma-Aldrich, St. Louis, Missouri.

[0150] EXAMPLE 1

[0151] Conventional resin solutions were prepared as follows: To a 1 -liter, four-neck round-bottom flask equipped with a mechanical agitator, reflux condenser, and a thermocouple connected to a heating control device and a heating device was added n- butanol (150 g) and Alnovol PN320 (a conventional phenol-based novolac from Allnex) (90 g). The resin was dissolved at a temperature of about 65°C for about 30 minutes and a clear orange solution was obtained. Other resin solutions shown in Table 1 were prepared using a similar process.

[0152] Table 1

[0153] EXAMPLE 2

[0154] Dibutoxymethane was prepared as follows: To a one-liter, four-neck roundbottom flask equipped with a mechanical agitator, a nitrogen inlet, a reflux condenser, a Dean-Stack receiver, and a thermocouple connected to a heating control device and a heating device was added n-butanol (142.1 g), paraformaldehyde (96%, 17.6 g) and sulfuric acid (98%, 0.22 g). This mixture in the flask was heated to about 85°C. The reaction w as maintained at about 85°C for about 4 hours and distillate (60.4 g) was collected in the Dean- Stack receiver until formaldehyde content was below about 0.01%. Next, additional n- Butanol (55. 1 g) was charged to the flask for weight balance. The resultant product was a clear solution.

[0155] To determine formaldehyde content for this Example, the procedures of EN ISO 9397 were used for monitoring the reaction of formaldehyde content as follow s: a given weight of the sample measured on analytical balance was dissolved in 100 mL of methanol. The pH of the solution w as adjusted to 3.5 using a diluted hydrochloric acid solution or KOH solution. Then, 15 ml of 10% hydroxylamine hydrochloride aqueous solution (pH 3.5) was then added into the solution. After mixing 10 minutes, the solution was titrated with 0. 1 N standard potassium hydroxide on Metrohm 751 GDP Titrino (± 0.01 ml) until pH value reaches to 3.50. A calculation of percent formaldehyde was performed based on following equation: % formaldehyde = (3.0 x 0. 1 V (ml)) / (sample size (g))

[0156] EXAMPLE 3

[0157] Another conventional novolac resin was functionalized as follows: To a one- liter, four-neck round-bottom flask equipped with a mechanical agitator, a nitrogen inlet, a reflux condenser, a Dean-Stack receiver, and a thermocouple connected to a heating controldevice and a heating device was added n-butanol (70.0 g), dibutoxymethane (Sigma-Aldrich) (80.6 g) and phenol-based novolac resin (Alnovol PN320, Allnex) (85.0 g) at ambient temperature. The novolac resin was dissolved in n-butanol and the dibutoxymethane at 65°C to form a clear yellow solution. Sulfuric acid (98%, 0.22 g) was added to the flask. The reaction mixture was heated and maintained at 85°C about 4 hours until the solubility' of the sample was less than 1% by weight in the test solution. The product was clear dark orange liquid. Viscosity was 292 cps, the solid content was 39.9%. free formaldehyde was less than 0.01%.

[0158] EXAMPLE 4

[0159] Four different coated substrates were prepared using the resin samples of Example 1 and the dibutoxymethane (DBM) of EXAMPLE 2 and were formulated as shown in Table 2 below. The solutions were applied to tin plate (ETP) at about 4 to about 6 mg per square inch of wet coating thickness and were baked at 400°F for about 5 minutes and then the baked samples were immersed in methyl ethyl ketone (MEK) for 60 minutes at ambient temperatures (RT). The sample was fully cured if it remained in a hard solid form in MEK. The sample is partially cured if it becomes soft sw ollen form in MEK. A non-cured sample is either completely or mostly dissolved in MEK. Results are provided in Table 2.

[0002] Table 2. Formulation of Phenolic with DBM

[0160] EXAMPLE 5

[0161] Twelve different coated substrates using dibutoxymethane (DBM) (Sigma- Aldrich) and sulfuric acid catalyst were formulated as shown in Table 3 below. The solutions were applied to tin plate (ETP) at a w et coating w eight of about 4 to about 6 mg per square inch and baked at 400°F for 5 minutes and then the baked samples were immersed in MEKfor 60 minutes at ambient temperatures to evaluate cure. The sample was fully cured if it remains in a hard solid form in the MEK. The sample was partially cured if it becomes a soft swollen form in MEK. A non-cured sample is either completely or mostly dissolved in MEK. Results are provided in Table 3 below

[0162] Table 3. Formulation of Phenolic and DBM

[0163] EXAMPLE 6

[0164] Two different coated substrates were prepared using conventional novolac resins, DBM, and sulfonic acids as shown in Table 4. The solutions were applied to tin plate (ETP) at a wet coating weight of about 4 to about 6 mg square inch and baked at 400°F for 5 minutes and then the baked samples ware immersed in MEK for 60 minutes at ambient temperatures. In Table 4 below. Cycat 600 (Cytec) was used and is an aromatic sulfonic acid catalyst and Nacure 5929 (King Industries) was also used and is a latent aromatic sulfonic acid catalyst. The sample was fully cured if it remained in a hard solid form in MEK. The sample was partially cured if it becomes a soft swollen form in MEK. A non-cured sample is either completely or mostly dissolved in MEK. Results are provided in Table 4 below.

[0165] Table 4: Formulation of Phenolic and DBM

[0166] EXAMPLE 7

[0167] This example compares the stability of functionalized novolac resins made by the reaction of Alnovol PN 320 and DBM shown in EXAMPLE 3 (e.g., Alnovol PN 320 (conventional phenol-based novolac) from Allnex) having a solids content of about 37.5%, a viscosity of 81 cp, and a number average molecular weight of about 1,040 g / mol. Table 5 provides stability.

[0168] Table 5: Viscosity Stability after 90 days at ambient temperature

[0169] In the case of Samples 1 , 2 and 4, the reactions of conventional novolac PN 320 with DBM or formaldehyde with H2SO4 catalyst were stopped when the reaction reached the end point of the solubility'. Sample 1 fresh was good but gelled after 90 days because it was not neutralized (e.g., pH < 0). Sample 2 did not gel but viscosity increased more than 100% because it was not fully neutralized (e.g., pH <1). For sample 3, the reaction of conventional novolac (e.g., PN320) with DBM with H2SO4 was continued an additional one hour after it reached the end point of the solubility. The initial viscosity' of the fresh sample 3 was much higher than others and the sample was also not neutralized. Therefore, it gelled during a short aging at ambient temperature. Sample 4 was fully neutralized (e.g., pH >4.) with a common neutralization agent (e.g., sodium hydroxide, potassium hydroxide, and the like) and was stable with no viscosity7increase.

[0170] EXAMPLE 8

[0171] This example compares the cure in the context of MEK double rubs of a functionalized novolac resin obtained from conventional novolac resins (e.g., Alnovol PN 320 a conventional phenol-based novolac from Allnex) being either pre-reacted withdibutoxymethane or reacted in-situ with dibutoxymethan (DBM) in a coating composition a second polymer. Coated samples on tinplate were baked at 400°F for 10 minutes to achieve a dry coating weight of 4 to 6 mg / inch2. Table 6 provides the MEK double rubs (with numbers in () reflecting MEK double rubs are a 20 min soak in MEK at room temperature).

[0172] Table 6: MEK Double Rubs

[0173] EXAMPLE 9

[0174] The inventive first resin samples A and B (either the pre-reacted or blend, respectively) from Example 8 were further analyzed with the acry lic, polyester, and epoxy second polymers for time (minutes) to 63 percent of total cure compared to a resole control polymer without either samples A or B using a DMA analysis. Compositions were cured as described in Example 8 at 400°F for 10 minutes. Results are provided in Table 7 below showing comparable cure between the samples.

[0175] Table 7

[0176] EXAMPLE 10

[0177] The inventive phenolic novolac blend and pre-reacted first resins from Examples 8 and 9 were further evaluated for modulus build using a DMA analysis and compared to MEK double rubs in compositions using HEMA acrylic from Example 8. Coated samples were cured as described in Example 8. Storage modulus of the coated samples was evaluated using a DMA analysis as well as MEK double rubs. The Storage modulus is provided in FIG. 1 and the MEK double rubs is provided in Table 8 below.

[0178] Table 8: MEK double rubs

[0179] The complete disclosure of all patents, patent applications, and publications, and electronically available material cited herein are incorporated by reference. The foregoing detailed description and examples have been given for clarity of understanding only. No unnecessary limitations are to be understood therefrom. The invention is not limited to the exact details shown and described, for variations obvious to one skilled in the art will be included within the invention defined by the claims.

Claims

WHAT IS CLAIMED IS:

1. A food or beverage container coating composition comprising: a first resin having hydroxy-substituted phenyl groups; a reactive solvent comprising a dialkoxymethane having a boiling point of at least about 88°C, preferably at least about 130°C, and more preferably about 150°C to about 305°C; a second polymer; and wherein the food or beverage container coating composition includes an excess of the second polymer, on a weight basis, relative to the first resin.

2. The food or beverage container coating composition of claim 1, wherein the first resin is a novalac resin, a resole resin, a novalac-type vinyl resin, a resole-type vinyl resin, a resin derived from vinyl phenolic monomers, or combinations thereof; preferably wherein the first resin is a novalac resin; and most preferably wherein the novalac resin is obtained from reactants including a phenolic compound and an aldehyde, preferably, formaldehyde, under acidic conditions (e.g., a pH of about 2 or less, and preferably , a pH of about 2 to about -2) and with a molar excess of the phenolic compound relative to the aldehyde (e.g., a molar ratio of the phenolic compound to the aldehyde of greater than 1 and, preferably about 1 to about 3).

3. The food or beverage container coating composition of any preceding claim, wherein the first resin has a number average molecular weight greater than about 500 (preferably greater than about 1000) and, more preferably, less than about 4000 (most preferably less than 3000) as measured by gel permeation chromatography (GPC) using polystyrene as a standard.

4. The food or beverage container coating composition of any previous claim, wherein the second polymer is capable of participating in a cross-linking reaction with the first resin in the presence of the dialkoxymethane reactive solvent (e.g., at a temperature of at least about 130°C for at least about 30 seconds).

5. The food or beverage container coating composition of any previous, wherein the dialkoxymethane of the reactive solvent has the structure of Formula I(Formula I) whereinRi and R2, independently, are a Cl to CIO alkyl group, a Cl to CIO alkylether group (e.g., an alkyd group having one or more carbon atoms replaced with an oxygen atom), preferably, a Cl to C6 alkyl group, more preferably, a C2 to C5 alkyl group, and most preferably, a C4 alkyl group; and each R3 is independently, hydrogen, or a Cl to C6 alkyl group, and preferably each R3 is hydrogen.

6. The food or beverage container coating composition of any preceding claim, wherein the dialkoxymethane reactive solvent includes di ethoxy methane, dipropoxymethane, dibutoxymethane, dipentanoxymethane, bis(butoxyethanoxy)methane, or combinations thereof, and preferably, the dialkoxymethane is dibutoxymethane.

7. The food or beverage container coating composition of any of claims 2 to 6, wherein the first resin comprises a novalac resin, and where the phenolic compound comprises phenol, cresol, resorcinol, xylenol, t-butyl phenol, cyclohexyl-methylphenol, dicyclopentadine, vinyl phenol, aminophenol, methoxyphenol, naphthol, cardanol, cardol, or combinations thereof and, preferably, phenol.

8. The food or beverage container coating composition of any of claims 2 to 7, wherein the first resin comprises a novalac resin, and where the aldehyde comprises formaldehyde, acetaldehyde, propionaldehyde, paraformaldehyde, butyraldehyde, oxaldehyde, trioxane (e.g.. a trimer of formaldehyde), hydroxybenzaldehyde (including any isomer thereof), furfural, furfurol, or combinations thereof, and preferably, formaldehyde.

9. The food or beverage container coating composition of any preceding claim, wherein the second polymer comprises a polyether, a polyester, an acrylic, a polyolefin, or amixture or copolymer thereof having hydroxyl groups (preferably, primary hydroxy groups) and / or carboxylic groups for reacting with the first resin.

10. The food or beverage container coating composition of any preceding claim, wherein the second polymer has an acid number of at least about 0 mg KOH / g, and preferably, about 0 mg KOH / g to about 150 mg KOH / g.

11. The food or beverage container coating composition of any preceding claim, wherein the second polymer has a hydroxyl number of at least about 15 mg KOH / g, and preferably, about 20 mg KOH / g to about 200 mg KOH / g.

12. The food or beverage container coating composition of any preceding claim, wherein second polymer second has has a glass transition temperature (Tg) of greater than 70°C, greater than 80°C, greater than 90°C, or greater than 100°C, and preferably, less than 150°C, less than 140°C, less than 120°C, or less than 110°C.

13. The food or beverage container coating composition of any preceding claim, wherein the reactive solvent is substantially formaldehyde free (e.g., about 100 ppm or less of unreacted formaldehyde, about 50 ppm or less, or about 10 ppm or less of unreacted formaldehyde) as measured pursuant to EN ISO 9397.

14. The food or beverage container coating composition of any preceding claim, wherein the food or beverage container coating composition includes about 10 to about 50 weight percent of total resin solids (preferably, about 15 to about 35 weight percent, and more preferably about 20 to about 40 weight percent).

15. The food or beverage container coating composition of any preceding claim, wherein the food or beverage container coating composition is substantially free of each of bisphenol A and bisphenol S.

16. The food or beverage container coating composition of any preceding claim, wherein the coating composition includes about 5 to about 50 weight percent of the first resin (preferably, about 15 to about 35 weight percent of the first resin) and about 50 to about 95weight percent of the second polymer (preferably, about 60 to about 80 weight percent of the second resin), based on total resin solids.

17. The food or beverage container coating composition of any preceding claim, wherein the coating composition includes about 5 to about 35 weight percent of the reactive solvent including the dialkoxymethane.

18. The food or beverage container coating composition of any preceding claim, further including a lubricant.

19. The food or beverage container coating composition of claim 18, wherein the lubricant comprises Carnauba wax, polyethylene-based wax, Fischer-tropsch wax, fatty acid ester wax, silicon-based wax, lanolin wax, hydroxyl-functional poly siloxane wax or a combination thereof.

20. The food or beverage container coating composition of any preceding claim, wherein the coating composition includes at least about 25 weight percent of water.

21. The food or beverage container coating composition of any preceding claim, wherein the coating composition further includes one or more water-miscible organic solvents.

22. The food or beverage container coating composition of claim 21, wherein the water-miscible organic solvent comprises isopropyl alcohol, ethanol, methanol, butyl alcohol, amyl alcohol, a diols, a glycol ether, a glycol ester, acetone, methyl ethyl ketone, tetrahydrofuran, or a mixture thereof.

23. The food or beverage container coating composition of claims 21 or 22. wherein the coating composition comprises from about 3.5 weight percent to about 15 weight percent of the one or more water-miscible organic solvents.

24. The food or beverage container coating composition of any preceding claim, wherein the coating composition includes at least about 5 weight percent of one or more organic solvents.

25. The food or beverage container coating composition of any of claims 1 to 19, wherein the coating composition is an organic-solvent based coating composition that includes, if any, preferably no more than 1% by weight of water, and more preferably no more than 0.1% by weight of water.

26. The food or beverage container coating composition of any preceding claim, wherein the food or beverage container coating composition forms a cured interior food or beverage container coating that includes less than 50 ppm extractables, if any, when tested pursuant to the Global Extraction Test.

27. The food or beverage container coating composition of any preceding claim, wherein upon baking (e g., a temperature of at least about 135°C, and preferably, about 200°C to about 250°C), the coating composition forms a functionalized novalac resin that is reaction product of the first resin and the reactive solvent.

28. The food or beverage container coating composition of any preceding claim, wherein the first resin (or the functionalized novalac-type resin) has a backbone including hydrocarbyl-bridged aromatic groups with alkoxymethylene substituents.

29. The food or beverage container coating composition of claim 28, wherein the hydrocarbyl-bridge is a methylene group.

30. The food or beverage container coating composition of claim 28 or 29, wherein the backbone is free of ether bridges between aromatic groups.

31. The food or beverage container coating composition of any claims 1 to 27, wherein the first resin is a novalac-type vinyl resin, a resole-type vinyl resin, a vinyl phenolic resin, or combinations thereof.

32. The food or beverage container coating composition of any preceding claim, wherein the coating composition, when applied to tin plate (ETP) and cured at 200°C for 10 minutes to achieve an average dry film thickness of 6 mg / in2, exhibits at least about 50 MEK double rubs when measured pursuant to ASTM D5402.

33. The food or beverage container coating composition of any preceding claim, wherein the coating composition includes less than about 1000 ppm of free formaldehyde, preferably less than 500 ppm of formaldehyde, and most preferably less than 100 ppm of free formaldehyde determined using the procedures of EN ISO 9397.

34. An article comprising a food or beverage container, or a portion thereof, the article comprising: a metal substrate: and a thermally -cured coating disposed on at least a portion of the metal substrate, wherein the thermally -cured coating is formed by baking the food or beverage container coating composition of any one of claims 1 to 33 at an oven temperature of at least about 135°C, and preferably about 200°C to about 250°C.

35. The article of claim 34, wherein, during the baking, the coating composition forms a functionalized novalac-type resin.

36. The article of claim 35 , wherein the functionalized novalac-type resin has a backbone including hydrocarbyl -bridged aromatic groups with alkoxymethylene substituents or a backbone having pendant aromatic groups.

37. The article of claim 36. wherein the hydrocarbyl-bridge is a methylene group.

38. The article of claim 36 or 37, wherein the backbone is free of ether bridges between aromatic groups.

39. The article of claim 35, wherein the functionalized novalac-type resin has the structure of Formula II(Formula II) wherein R4 is a Cl to CIO alkyl group or a Cl to CIO alkylether group (e.g., an alkyl group having one or more carbon atoms replaced with an oxygen atom) and, preferably, a Cl to C6 alkyd group, more preferably, a C2 to C5 alkyl group, and most preferably, a C4 alkyl group.

40. The article of any one of claims 34 to 39, wherein the food or beverage container coating composition is applied on a food or beverage-contacting surface of the metal substrate.

41. The article of any one of claims 34 to 40, wherein the metal substrate is tin plate (ETP) and has a thickness of 0. 17 to 0.8mm.

42. The article of any one of claims 34 to 41, wherein the coating composition, when dried, as a coating thickness of 4 to 8 mg / in2.

43. A method of forming a food or beverage container, the method comprising providing the food or beverage container coating composition of any one of claims 1 to 33; and applying the food or beverage container coating composition on a metal substrate, or portion thereof, prior to, or after, forming the metal substrate into a food or beverage container or a portion thereof.

44. The method of claim 43, further comprising baking and curing the food or beverage container coating composition after applying to the metal substrate.

45. The method of claim 43, wherein the metal substrate is heated at an oven temperature of at least about 130°C for at least about 30 seconds.

46. A method comprising causing the coating composition of any one of claims 1 to 33 to be used on a metal substrate for a food or beverage container or a portion thereof.

47. The method of any of claims 43 to 46, wherein, during the baking, the coating composition forms a functionalized novalac-type resin.

48. The method of any of claims 43 to 47, wherein the functionalized novalac resin has a backbone including hydrocarbyl-bridged aromatic groups with alkoxymethylene substituents or a backbone having pendant aromatic groups.

49. The method of any of claims 43 to 48, wherein the hydrocarbyl-bridge is a methylene group.

50. The method of any of claims 43 to 49, wherein the backbone is free of ether bridges between aromatic groups.

51. The method of any of claims 43 to 50, wherein the metal substrate is tin plate (ETP) and has a thickness of 0.17 to 0.8mm.

52. The method of any of claims 43 to 50, wherein the coating composition, when dried, as a coating thickness of 4 to 8 mg / in2.

53. The method, the article, or the food or beverage container coating composition of any preceding claim, wherein when the food or beverage container coating composition is applied to tinplate and baked at 400°F for 10 minutes to achieve a dry coating weight of 4 to 6 mg / inch2achieves a time to 63 percent cure as measured using the DMA analysis as described herein of about 115 minutes or less, about 50 minutes or less, about 20 minutes or less, about 15 minutes or less, or about 10 minutes or less.

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