Coating composition and coating system

Abstract

A coating composition comprising: a polyester material, and a benzoguanamine or a derivative thereof wherein the coating composition is substantially free of bisphenol A (BPA), bisphenol F (BPF), bisphenol A diglycidyl ether (BADGE), and bisphenol F diglycidyl ether (BFDGE), and wherein the coating composition has a flexibility of at least 20 mm when cured, and wherein the coating composition is substantially free of bisphenol A (BPA), bisphenol F (BPF), bisphenol A diglycidyl ether (BADGE) and bisphenol F diglycidyl ether (BFDGE). The present invention relates to a scratch-resistant film having a scratch resistance of at least 700 g, measured according to ISO Standard 1518-1: 20 11, according to the tensile and retensile test method and treatment in a 1% salt (NaCl) tap water solution for 60 minutes at 130 DEG C, and a scratch resistance of at least 700 g, measured according to ISO Standard 1518-1: 20 11.

Description

[0001] This application is a divisional application of Chinese patent application No. 201780067701.9, filed on November 3, 2017, entitled "Coating Composition and Coating System".

[0002] This invention relates to a coating composition, particularly a coating composition for a metal substrate. The invention further relates to a coating system, particularly a coating system for a metal substrate. The invention also relates to a metal substrate, such as a food or beverage container or a portion thereof, coated with the coating composition or coating system.

[0003] Many types of coatings have been used to coat food and / or beverage containers. These coating systems typically possess certain properties such as the ability to be applied at high speeds, acceptable adhesion to the substrate, safety for food contact, and suitability for their end use. Typically, coatings possess one or more of these advantageous properties, depending on their final end application.

[0004] Many coating compositions contain bisphenol A (BPA). BPA is considered harmful to human health and therefore its removal from coatings is desirable. Derivatives of BPA, such as bisphenol A diglycidyl ether (BADGE), epoxy linear phenolic resins prepared from BPA and bisphenol F (BPF), and polyols are also considered problematic. Therefore, it is desirable to provide coating compositions that are free of BPA, BADGE, and / or other derivatives, but retain the aforementioned desired properties.

[0005] One objective of this invention is to provide one or more solutions to the above and other problems.

[0006] According to a first aspect of the present invention, a coating composition is provided, comprising:

[0007] Polyester materials, and

[0008] Benzoguanidine or its derivatives,

[0009] The coating composition is substantially free of bisphenol A (BPA), bisphenol F (BPF), bisphenol A diglycidyl ether (BADGE), and bisphenol F diglycidyl ether (BFDGE), and the coating composition, when cured, has a flexibility of at least 20 mm, as determined by tensile and re-tensile testing methods and by treatment in a 1% salt (NaCl) tap water solution at 130°C for 60 minutes, and a scratch resistance of at least 700 g, as determined according to ISO standard 1518-1:2011.

[0010] The coating composition according to the present invention comprises a polyester material. The polyester material according to the present invention may comprise a reaction product of a polyacid and a polyol.

[0011] As used herein, "polyacid" and similar terms refer to compounds having two or more carboxylic acid groups, such as 2, 3, or 4 acid groups, and comprising esters (where one or more acid groups are esterified) or anhydrides of polyacids. Suitablely, such polyacids are organic polyacids.

[0012] The carboxylic acid group of the polyacid can be connected by a bridging group selected from the following: alkylene; alkenylene; ynylene; or arylene.

[0013] Polyester materials can be formed from any suitable polyacid. Examples of suitable polyacids include, but are not limited to, the following: maleic acid, fumaric acid, itaconic acid, adipic acid, azelaic acid, succinic acid, sebacic acid, glutaric acid, decanoic acid, dodecanoic acid, phthalic acid, isophthalic acid, 5-tert-butylisophthalic acid, tetrachlorophthalic acid, tetrahydrophthalic acid, trimellitic acid, naphthalene dicarboxylic acid, naphthalene tetracarboxylic acid, terephthalic acid, hexahydrophthalic acid, methyl hexahydrophthalic acid, dimethyl terephthalate, cyclohexane dicarboxylic acid, chlorobenzyl anhydride, 1,3-cyclohexane dicarboxylic acid, 1,4-cyclohexane dicarboxylic acid, tricyclodecane polycarboxylic acid, inner methylene tetrahydrophthalic acid, inner ethyl hexahydrophthalic acid, cyclohexane tetracarboxylic acid, cyclobutane tetracarboxylic acid; esters and anhydrides of all the above acids, and combinations thereof.

[0014] As used herein, "polyol" and similar terms refer to compounds having two or more hydroxyl groups, such as 2, 3, or 4 hydroxyl groups. The hydroxyl groups of a polyol can be linked by bridging groups selected from the following: alkylene; alkenylene; ynylene; or arylene. Suitably, the polyol is an organic polyol.

[0015] The polyester material can be formed from any suitable polyol. Suitable examples of polyols include, but are not limited to, the following: alkylene glycols such as ethylene glycol; propylene glycol; diethylene glycol; dipropylene glycol; triethylene glycol; tripropylene glycol; hexanediol; polyethylene glycol; polypropylene glycol and neopentyl glycol; hydrogenated bisphenol A; cyclohexanediol; propylene glycol, including 1,2-propanediol; 1,3-propanediol; butyl ethyl propylene glycol; 2-methyl-1,3-propanediol; and 2-ethyl-2-butyl-1,3-propanediol; butanediol, including 1,4-butanediol; 1,3-Butanediol; and 2-ethyl-1,4-butanediol; pentanediol, including trimethylpentanediol and 2-methylpentanediol; cyclohexanediol; hexanediol, including 1,6-hexanediol; caprolactone diol (e.g., the reaction product of ε-caprolactone and ethylene glycol); hydroxyalkylated bisphenols; polyether diols such as poly(oxytetramethylene) diol; trimethylolpropane; pentaerythritol; dipentaerythritol; trimethylolethane; trimethylolbutane; dimethylolcyclohexane; glycerol, etc., or combinations thereof.

[0016] Polyester materials may contain polymers or copolymers formed by the reaction of diols and diacids; polyols or polyacid components may optionally be used to produce branched polymers.

[0017] Polyester materials can be formed from diacids. Suitable examples of diacids include, but are not limited to, the following: phthalic acid; isophthalic acid; terephthalic acid; 1,4-cyclohexanedicarboxylic acid; succinic acid; adipic acid; azelaic acid; sebacic acid; fumaric acid; 2,6-naphthalenedicarboxylic acid; n-phthalic acid; phthalic anhydride; tetrahydrophthalic anhydride; maleic anhydride; succinic anhydride; itaconic anhydride; diester materials such as dimethyl ester derivatives such as dimethyl isophthalate, dimethyl terephthalate, dimethyl 1,4-cyclohexanedicarboxylic acid, dimethyl 2,6-naphthalenedicarboxylic acid, dimethyl fumarate, dimethyl n-phthalate, dimethyl succinate, dimethyl glutarate, dimethyl adipate; esters and anhydrides of all the above acids; and mixtures thereof.

[0018] Suitablely, the polyester material may be formed from terephthalic acid, isophthalic acid, sebacic acid, or a combination thereof.

[0019] Polyester materials can be formed from diols. The polyester material can be formed from any suitable diol. Examples of suitable diols include, but are not limited to, the following: ethylene glycol; 1,2-propanediol; 1,3-propanediol; 1,2-butanediol; 1,3-butanediol; 1,4-butanediol; but-2-ene 1,4-diol; 2,3-butanediol; 2-methyl-1,3-propanediol; 2,2'-dimethyl-1,3-propanediol (neopentyl glycol); 1,5-pentanediol; 3-methyl-1,5-pentanediol; 2,4-diethyl- 1,5-Pentanediol; 1,6-Hexanediol; 2-Ethyl-1,3-Hexanediol; Diethylene glycol; Triethylene glycol; Dipropylene glycol; Tripropylene glycol; 2,2,4-Trimethylpentane-1,3-diol; 1,4-Cyclohexanediol; Tricyclodecanediol; 2,2,4,4-Tetramethylcyclobutane-1,3-diol; Isosorbide; 1,4-Cyclohexanediol; 1,1'-Isopropylidene-bis(4-cyclohexanol); and mixtures thereof.

[0020] Suitablely, the polyester material may be formed from 2,2'-dimethyl-1,3-propanediol (neopentylene glycol), 1,4-butanediol, 2-methyl-1,3-propanediol, ethylene glycol, 1,6-hexanediol, or combinations thereof.

[0021] Other suitable examples of polyacids (which may optionally be used to produce branched polymers) include, but are not limited to, the following: trimellitic anhydride; trimellitic acid; pyromellitic acid; esters and anhydrides of all the aforementioned acids; and mixtures thereof.

[0022] Other suitable examples of polyols (which may optionally be used to produce branched polymers) include, but are not limited to, the following: glycerol; trimethylolpropane; trimethylolethane; 1,2,6-hexanetriol; pentaerythritol; erythritol; di(trimethylol)propane; dipentaerythritol; N,N,N',N'-tetra(hydroxyethyl)hexamethylenediamide; N,N,N',N'-tetra(hydroxypropyl)hexamethylenediamide; other primary hydroxyl functionalized branched monomers; or mixtures thereof.

[0023] As used herein, the terms "alkane" or "alkyl" unless otherwise defined refer to a saturated hydrocarbon group that is a straight-chain, branched, cyclic, or polycyclic moiety or combination thereof, and contains 1-20 carbon atoms, suitably 1-10 carbon atoms, more suitably 1-8 carbon atoms, still more suitably 1-6 carbon atoms, still more suitably 1-4 carbon atoms. These groups may optionally be chlorinated, bromine, iodinated, cyano, nitro, OR 19 OC(O)R 20 C(O)R 21 C(O)OR 22 NR 23 R 24 C(O)NR 25 R26 SR 27 C(O)SR 27 C(S)NR 25 R 26 aryl or heteroatom substitution, where R 19 -R 27 Each group independently represents hydrogen, aryl, or alkyl, and / or is interrupted by an oxygen or sulfur atom, or by a silane or dialkylsiloxane group. Examples of such groups can be independently selected from methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, 2-methylbutyl, pentyl, isopentyl, hexyl, cyclohexyl, 3-methylpentyl, octyl, etc. As used herein, the term "alkylene" refers to a divalent alkyl group as defined above. For example, when represented as alkylene, an alkyl group such as methyl (represented as -CH3) becomes methylene-CH2-. Other alkylene groups should be understood accordingly.

[0024] As used herein, the term "alkenyl" refers to a hydrocarbon group having double bonds, suitably up to four double bonds, which is a straight-chain, branched, cyclic, or polycyclic moiety or combination thereof, and contains 2-18 carbon atoms, suitably 2-10 carbon atoms, more suitably 2-8 carbon atoms, still more suitably 2-6 carbon atoms, still more suitably 2-4 carbon atoms. These groups may optionally be hydroxyl, chlorine, bromine, iodine, cyano, nitro, OR 19 OC(O)R 20 C(O)R 21 C(O)OR 22 NR 23 R 24 C(O)NR 25 R 26 SR 27 C(O)SR 27 C(S)NR 25 R 26 Or aryl substitution, where R 19 -R 27 Each group independently represents hydrogen, aryl, or alkyl, and / or is interrupted by an oxygen or sulfur atom, or by a silane or dialkylsiloxane group. Examples of such groups can be independently selected from alkenyl groups, including vinyl, allyl, isopropenyl, pentenyl, hexenyl, heptenyl, cyclopropenyl, cyclobutenyl, cyclopentenyl, cyclohexenyl, 1-propenyl, 2-butenyl, 2-methyl-2-butenyl, isoprene, farnesyl, geranyl, geranylgeranyl, etc. As used herein, the term "alkenyl" refers to a divalent alkenyl group as defined above. For example, when represented as alkenyl, an alkenyl group such as vinyl (represented as -CH=CH2) becomes vinylene-CH=CH-. Other alkenyl groups should be understood accordingly.

[0025] As used herein, the term "alkynyl" refers to a hydrocarbon group having three bonds, preferably up to four, which is a straight-chain, branched, cyclic, or polycyclic moiety or combination thereof and has 2-18 carbon atoms, preferably 2-10 carbon atoms, more preferably 2-8 carbon atoms, still more preferably 2-6 carbon atoms, still more preferably 2-4 carbon atoms. These groups may optionally be hydroxyl, chlorine, bromine, iodine, cyano, nitro, OR 19 OC(O)R 20 C(O)R 21 C(O)OR 22 NR 23 R 24 C(O)NR 25 R 26 SR 27 C(O)SR 27 C(S)NR 25 R 26 Or aryl substitution, where R 19 -R 27 Each group independently represents hydrogen, aryl, or a lower alkyl group, and / or is interrupted by an oxygen or sulfur atom, or by a silane or dialkylsiloxane group. Examples of such groups can be independently selected from ynyl groups, including ethynyl, propynyl, propynyl, butynyl, pentyynyl, hexynyl, etc. As used herein, the term "ynynyl" refers to a divalent ynyl group as defined above. For example, when represented as ynynyl, an ynyl group such as ethynyl (represented as -C≡CH) becomes ethynyl-C≡C-. Other ynynyl groups should be understood accordingly.

[0026] As used herein, the term "aryl" refers to an organic group derived from an aromatic hydrocarbon by removing a hydrogen atom, and includes any monocyclic, bicyclic, or polycyclic carbon ring with up to 7 members in each ring, wherein at least one ring is aromatic. These groups may optionally be hydroxyl, chlorine, bromine, iodine, cyano, nitro, OR 19 OC(O)R 20 C(O)R 21 C(O)OR 22 NR 23 R 24 C(O)NR 25 R 26 SR 27 C(O)SR 27 C(S)NR 25 R 26 Or aryl substitution, where R 19 -R 27Each independently represents hydrogen, aryl or lower alkyl, and / or interrupted by oxygen or sulfur atoms, or interrupted by silane or dialkylsilane groups. Examples of such groups can be independently selected from phenyl, p-tolyl, 4-methoxyphenyl, 4-(tert-butoxy)phenyl, 3-methyl-4-methoxyphenyl, 4-fluorophenyl, 4-chlorophenyl, 3-nitrophenyl, 3-aminophenyl, 3-acetaminophenyl, 4-acetaminophenyl, 2-methyl-3-acetaminophenyl, 2-methyl-3-aminophenyl, 3-methyl-4-aminophenyl, 2-amino-3-methylphenyl, 2,4-dimethyl-3-aminophenyl, 4-hydroxyphenyl, 3-methyl-4-hydroxyphenyl, 1-naphthyl, 2-naphthyl, 3-amino-1-naphthyl, 2-methyl-3-amino-1-naphthyl, 6-amino-2-naphthyl, 4,6-dimethoxy-2-naphthyl, tetrahydronaphthyl, indanyl, biphenyl, phenanthryl, anthraceneyl, or acenaphthyl, etc. As used herein, the term "aryl" refers to the divalent aryl group as defined above. For example, when represented as arylene, aryl groups such as phenyl (represented as -Ph) become phenylene-Ph-. Other arylene groups should be understood accordingly.

[0027] To avoid ambiguity, references to alkyl, alkenyl, alkynyl, aryl, or aralkyl groups in this article should be interpreted accordingly. For example, references to alkyl in aminoalkyl or alkoxy in alkane should be interpreted as the aforementioned alkane or alkyl groups.

[0028] The polyester material can be formed from any suitable molar ratio of polyacid:polyol. The polyacid:polyol molar ratio in the polyester material can be 10:1 to 1:10, suitably 5:1 to 1:5, for example 3:1 to 1:3, or even 2:1 to 1:2. Suitably, the polyacid:polyol molar ratio in the polyester material can be 1.5:1 to 1:1.5, for example 1.2:1 to 1:1.2.

[0029] The polyester material can be formed from any suitable molar ratio of diacid:diol. The diacid:diol molar ratio in the polyester material can be 10:1 to 1:10, suitably 5:1 to 1:5, for example 3:1 to 1:3, or even 2:1 to 1:2. Suitably, the diacid:diol molar ratio in the polyester material can be 1.5:1 to 1:1.5, for example 1.2:1 to 1:1.2, or even 1.1:1 to 1:1.1.

[0030] The polyester material may optionally be formed from any suitable molar ratio of diacid + diol: polyacid and / or polyol. The polyester material may have a molar ratio of diacid + diol: polyacid and / or polyol of 100:1 to 1:1, suitably 100:1 to 5:1, for example 100:1 to 20:1, or even 100:1 to 50:1.

[0031] The polyester material may optionally be formed from other monomers. Suitably, the polyester material may optionally include other monomers selected from monoacids or monohydroxy alcohols or combinations thereof. Suitably, the optional other monomers may be organic.

[0032] The polyester material may optionally be formed from another monoacid. As used herein, "monoacid" and similar terms refer to a compound having a carboxylic acid group, and include esters or anhydrides of monoacids (wherein the acid group is esterified). The monoacid is suitably an organic monoacid.

[0033] The polyester material may optionally be formed from any other suitable monoacid. Suitable examples include, but are not limited to, the following: benzoic acid; cyclohexanecarboxylic acid; tricyclodecanecarboxylic acid; camphoric acid; benzoic acid; tert-butylbenzoic acid; C1-C 18 Aliphatic carboxylic acids such as acetic acid; propionic acid; butyric acid; hexanoic acid; oleic acid; linoleic acid; undecanoic acid; lauric acid; isononanoic acid; fatty acids; hydrogenated fatty acids of naturally occurring oils; esters and / or anhydrides of any of the aforementioned acids and combinations thereof.

[0034] The polyester material may optionally be formed from another monohydroxy alcohol. As used herein, "monohydroxy alcohol" and similar terms refer to compounds having one hydroxyl group. Suitably, the monohydroxy alcohol is an organic monohydroxy alcohol.

[0035] The polyester material may optionally be formed from any suitable other monohydroxy alcohol. Suitable examples include, but are not limited to, the following: benzyl alcohol; hydroxyethoxybenzene; methanol; ethanol; propanol; butanol; pentanol; hexanol; heptanol; dodecyl alcohol; octadecyl alcohol; oleyl alcohol; undecyl alcohol; cyclohexanol; phenol; phenyl alcohol; methylphenyl alcohol; cresol; monoethers of diols; halogenated or other substituted alcohols and combinations thereof.

[0036] The polyester material may include commercially available polyester materials. Suitable commercially available polyester materials include, but are not limited to, the following: those marketed under the trademark URALAC (RTM) from DSM, such as URALAC SN 800, URALAC SN 805, URALAC SN 808, URALAC SN 842, URALAC SN 859, URALAC SN 860, URALAC SN 905, URALAC 908, URALAC 989, or URALAC SN 978; those marketed under the trademark ITALKID (RTM) from Galstaff-Multiresine, such as ITALKID 212, ITALKID 218, ITALKID 226, ITALKID 228, ITALKID 231, or ITALKID 300; and those marketed under the trademark DOMOPOL (RTM) from Helios, such as DOMOPOL 5101, DOMOPOL... DOMOPOL 5102, DOMOPOL 5111, DOMOPOL 5112, DOMOPOL 5113, DOMOPOL 5117, DOMOPOL 5132; those sold under the trademark DYNAPOL (RTM) from Evonik, such as DYNAPOL LH 318, DYNAPOL LH818, DYNAPOL LH 820, DYNAPOL LH 823, DYNAPOL LH 830, DYNAPOL LH 833, DYNAPOL L912, DYNAPOL L 952, DYNAPOL L 206, DYNAPOL L 860, or DYNAPOL L 600; those sold under the trademark URALAC (RTM) from DSM, such as URALAC P 1580, URALAC 4215, ... 5080, URALAC 5930 or URALAC 6024; those marketed under the trademark URADIL (RTM) from DSM, such as URADIL 250, URADIL 255, URADIL 258, URADIL SZ 260 or URADIL SZ 262; those marketed under the trademark ITALESTER (RTM) from Galstaff-Multiresine, such as ITALESTER 217 or ITALESTER 218; and combinations thereof.

[0037] The polyester material can have any suitable number-average molecular weight (Mn). The Mn of the polyester material can be 500 Daltons (Da=g / mol)-250000 Da, suitablely 500 Da-200000 Da, for example 1000 Da-150000 Da, or even 1000-100000 Da.

[0038] The number-average molecular weight can be measured by any suitable method. Techniques for measuring number-average molecular weight are well known to those skilled in the art. Suitablely, and as reported herein, Mn can be determined by gel permeation chromatography using a polystyrene standard according to ASTM D6579-11 (“Standard Practice for the Mean Molecular Weight and Molecular Weight Distribution of Hydrocarbons, Rosin and Terpene Resins by Size Exclusion Chromatography”; UV detector; 254 nm, solvent: unstabilized THF, retention time marker: toluene, sample concentration: 2 mg / ml).

[0039] The polyester material can have any suitable weight-average molecular weight (Mw). The Mw of the polyester material can be 500 Daltons (Da=g / mol) to 250,000 Da, suitablely 500 Da to 200,000 Da, for example 1,000 Da to 150,000 Da, or even 1,000 to 100,000 Da.

[0040] Those skilled in the art will understand that the techniques used to measure number-average molecular weight can also be used to measure weight-average molecular weight.

[0041] The polyester material can have any suitable glass transition temperature (Tg). The Tg of the polyester material can be from -20°C to 120°C, suitablely from 0°C to 120°C, for example from 10°C to 105°C.

[0042] The glass transition temperature (Tg) of this polyester material can be measured by any suitable method. Methods for measuring Tg are well known to those skilled in the art. Suitablely and as reported herein, Tg was measured according to ASTM D6604-00 (2013) (“Standard Practice for Glass Transition Temperature of Hydrocarbon Resins by Differential Scanning Calorimetry”. Heat flux differential scanning calorimetry (DSC), sample pan: aluminum, reference: blank, calibration: indium and mercury, sample weight: 10 mg, heating rate: 20 °C / min).

[0043] The polyester material can have any suitable total hydroxyl value (OHV). The total OHV of the polyester material can be 0-120 mg KOH / g. Suitablely, the total OHV of the polyester material can be 0-110 mg KOH / g, for example 10-110 mg KOH / g, or even 10-100 mg KOH / g.

[0044] As reported in this paper, total OHV is expressed on a solid basis.

[0045] The polyester material can have any suitable acid value (AV). The AV of the polyester material can be 0-120 KOH / g. Suitablely, the total AV of the polyester can be 1-100 mg KOH / g, for example 1-20 mg KOH / g, or even 1-10 mg KOH / g.

[0046] The AV reported here is based on solid-state representation.

[0047] The polyester material according to the invention can be prepared in the presence of an esterification catalyst. Suitably, the esterification catalyst can be selected to promote the reaction of the components by esterification and / or transesterification. Suitable examples of esterification catalysts for preparing the polyester material include, but are not limited to, the following: metal compounds such as stannous octoate; stannous chloride; butylstannic acid (hydroxybutyltin oxide); monobutyltin tri(2-ethylhexanoate); chlorobutyltin dihydrogen hydroxide; tetrapropyl titanate; tetrabutyl titanate; zinc acetate; acid compounds such as phosphoric acid; p-toluenesulfonic acid; dodecylbenzenesulfonic acid (DDBSA); and combinations thereof. The esterification catalyst may be dodecylbenzenesulfonic acid (DDBSA).

[0048] When present, the amount of esterification catalyst may be 0.001-1% by weight of the total polymer composition, preferably 0.01-0.2% by weight, for example 0.025-0.2% by weight.

[0049] The polyester material may contain the reaction products of the following components:

[0050] (i) 1,2-Propanediol,

[0051] (ii) terephthalic acid, and

[0052] (iii) Molecular weight increasers

[0053] The number-average molecular weight (Mn) of the polyester material is at least 6100 Da and the glass transition temperature (Tg) is at least 80 °C.

[0054] Here, "molecular weight increaser" refers to a substance that increases the number-average molecular weight (Mn) of polyester materials.

[0055] The molecular weight increaser can be any suitable compound capable of increasing the Mn content of the polyester material. Suitably, the molecular weight increaser may comprise polyacids, polyols, or combinations thereof.

[0056] Molecular weight increasers may contain polyacids. Suitably, the molecular weight increaser may contain diacids.

[0057] Molecular weight increasers contain diacids of general formula (I):

[0058] Formula (I)

[0059] Each R independently represents hydrogen or alkyl, alkenyl, alkynyl, or aryl;

[0060] n = 0 or 1; and where X represents a bridging group selected from the following: alkylene; alkenylene; ynylene; arylene; where the bridging group between the -COOR groups is C1 or C2.

[0061] Suitable examples of polyacid molecular weight increasers include, but are not limited to, the following: oxalic acid; malonic acid; succinic acid; phthalic acid; maleic acid; fumaric acid; itaconic acid; methylmalonic acid; ethylmalonic acid; propylmalonic acid; 2-methylsuccinic acid; 2-ethylsuccinic acid; 2-propylsuccinic acid; trans-cyclopentane-1,2-dicarboxylic acid; cis-cyclopentane-1,2-dicarboxylic acid; trans-cyclohexane-1,2-dicarboxylic acid; cis-cyclohexane-1,2-dicarboxylic acid; acids and anhydrides of all the above acids, and combinations thereof. The polyacid molecular weight increaser may contain maleic anhydride, itaconic acid, or combinations thereof.

[0062] Suitable, polyacid molecular weight increasers may include maleic anhydride.

[0063] Molecular weight increasers may contain polyols. Suitably, the molecular weight increaser may contain triols.

[0064] The hydroxyl groups of this polyol molecular weight increaser can be linked via C1-C3 alkylene groups. These C1-C3 alkylene groups can be substituted or unsubstituted. The C1-C3 alkylene groups can optionally be substituted with the following: halogen; hydroxyl; nitro; mercapto; amino; alkyl; alkoxy; aryl; sulfonyl; and sulfonoxy. The C1-C3 alkylene groups can be linear or branched. They can be saturated or unsaturated.

[0065] Suitablely, there are no more than 3 connecting carbon atoms between the hydroxyl groups.

[0066] Suitable examples of polyol molecular weight increasers include, but are not limited to, the following: methylene glycol; ethylene glycol; propylene glycol; neopentyl glycol; 1,2-propanediol; butylethylpropanediol; 2-methyl-1,3-propanediol; 2-ethyl-2-butyl-1,3-propanediol; trimethylolpropane; trimethylolethane; trimethylolethane; trimethylolpropane; glycerol; pentaerythritol; and combinations thereof. Suitably, the polyol molecular weight increaser comprises trimethylolpropane.

[0067] Terephthalic acid (ii) can be in any suitable form. It is well known to those skilled in the art that terephthalic acid is often provided in a form that also contains isophthalic acid as a contaminant. However, the terephthalic acid can also be provided in a form that contains substantially no isophthalic acid. "Substantially no" here means terephthalic acid containing less than 5 wt% isophthalic acid, preferably less than 2 wt% isophthalic acid, more preferably less than 0.05 wt% isophthalic acid. The terephthalic acid can also contain 0 wt% isophthalic acid.

[0068] The polyester material may contain any suitable molar ratio of (i)+(ii):(iii). The molar ratio of (i)+(ii):(iii) may be 100:1 to 1:1, for example, 80:1 to 5:1. As a non-limiting example, when the molecular weight increaser is a polyacid, the molar ratio of (i)+(ii):(iii) may be 25:1. As another non-limiting example, when the molecular weight increaser is a polyol, the molar ratio of (i)+(ii):(iii) may be 80:1.

[0069] Polyester materials can have low branching. The polyester material can be substantially linear or slightly branched. For example, the branching degree of the polyester material can be measured by the polydispersity index of the high molecular weight polyester material. The polydispersity index of the polymer is given by the ratio of Mw to Mn (Mw / Mn), where Mw is the weight-average molecular weight and Mn is the number-average molecular weight. Suitably, the polydispersity index of the polyester material is 1-20, suitably 1-10.

[0070] The molecular weight of the polyester material can be higher than the molecular weight of the entangled polyester material.

[0071] As used herein, "entanglement molecular weight" and similar terms refer to a molecular weight at which the polyester material becomes large enough to become entangled. To avoid ambiguity, this molecular weight can be either number-average or weight-average. Entanglement molecular weight is typically defined as a molecular weight at which the physical properties of the polyester material, particularly its viscosity, change.

[0072] Typically, the entanglement molecular weight is determined by plotting the logarithm of the melt viscosity against the logarithm of the polymer molecular weight. Typically, as the molecular weight increases, the graph follows a slightly upward-sloping linear path. However, once the entanglement molecular weight is reached, this slightly upward-sloping linear path increases to a rapidly sloping linear path. Therefore, the entanglement molecular weight can be determined as a point on the graph where the slope changes from slightly upward to rapidly upward.

[0073] Techniques for measuring melt viscosity are well known to those skilled in the art. Suitablely, melt viscosity can be measured at high shear rates, for example, when applied by a cone-plate rheometer, typically using standard methods such as those described in ASTM D4287. Films formed from polyester materials according to the invention with molecular weights higher than the critical entanglement molecular weight of the polyester material have been found to have excellent film-forming properties.

[0074] The components (i), (ii), and (iii) of the polyester material can be contacted in any order.

[0075] The polyester material can be prepared in a one-step process. Suitably, in the one-step process, components (i), (ii), and (iii) all react simultaneously. Suitably, the polyester material can be prepared in a one-step process, wherein the molecular weight increaser comprises a polyol.

[0076] Suitablely, in a one-step process, components (i), (ii) and (iii) can be contacted once at a first reaction temperature T1, wherein T1 can be 90°C-260°C, suitablely 200°C-250°C, for example, a temperature of 200°C-230°C.

[0077] Typically, in a one-step process, the reaction is carried out for a total time of 1 minute to 100 hours, for example, 2 hours to 80 hours. Those skilled in the art will understand that the reaction conditions can vary depending on the reactants used.

[0078] The polyester material may be present in any suitable amount in the coating composition of the present invention. The coating composition may contain 40-95 wt%, suitably 50-95 wt%, for example 60-90 wt% of the polyester material, based on the total solid weight of the coating composition. Suitably, the coating composition may contain 70-80 wt% of the first polyester resin material, based on the total solid weight of the coating composition.

[0079] The coating compositions of the present invention comprise benzoguanidine or its derivatives. Benzoguanidine or its derivatives may comprise commercially available benzoguanidine or its derivatives. Suitable examples of commercially available benzoguanidine and its derivatives include, but are not limited to, the following: benzoguanidine-formaldehyde based materials such as CYMEL(RTM) 1123 (commercially available from Cytec Industries), ITAMIN(RTM) BG 143 (commercially available from Galstaff Multiresine), or MAPRENAL(RTM) BF 892 (commercially available from Ineos); glycourea based materials such as CYMEL 1170 and CYMEL 1172 (commercially available from Cytec); and combinations thereof.

[0080] Benzoguanidine or its derivatives may be present in the coating compositions of the present invention in any suitable amount. The coating composition may contain at least 1 wt%, suitably at least 2 wt%, for example at least 3 wt%, or even at least 4 wt% of benzoguanidine or its derivatives, based on the total solid weight of the coating composition. Suitably, the coating composition may contain at least 4.5 wt% of benzoguanidine or its derivatives, based on the total solid weight of the coating composition. The coating composition may contain up to 40 wt%, suitably up to 30 wt%, for example up to 20 wt%, or even up to 15 wt% of benzoguanidine or its derivatives, based on the total solid weight of the coating composition. Suitably, the coating composition may contain up to 10 wt% of benzoguanidine or its derivatives, based on the total solid weight of the coating composition. The coating composition may contain 1-40 wt%, suitably 1-30 wt%, for example 1-20 wt%, or even 1-15 wt% of benzoguanidine or its derivatives, based on the total solid weight of the coating composition. Suitably, the coating composition may contain 1-10 wt% benzoguanamine or its derivatives, based on the total solid weight of the coating composition. The coating composition may contain 2-40 wt%, suitably 2-30 wt%, for example 2-20 wt%, or even 2-15 wt% benzoguanamine or its derivatives, based on the total solid weight of the coating composition. Suitably, the coating composition may contain 2-10 wt% benzoguanamine or its derivatives, based on the total solid weight of the coating composition. The coating composition may contain 3-40 wt%, suitably 3-30 wt%, for example 3-20 wt%, or even 3-15 wt% benzoguanamine or its derivatives, based on the total solid weight of the coating composition. Suitably, the coating composition may contain 3-10 wt% benzoguanamine or its derivatives, based on the total solid weight of the coating composition. The coating composition may contain 4-40 wt%, suitably 4-30 wt%, such as 4-20 wt%, or even 4-15 wt% of benzoguanamine or its derivatives, based on the total solid weight of the coating composition. Suitably, the coating composition may contain 4-10 wt% of benzoguanamine or its derivatives, based on the total solid weight of the coating composition. The coating composition may contain 4.5-40 wt%, suitably 4.5-30 wt%, such as 4.5-20 wt%, or even 4.5-15 wt% of benzoguanamine or its derivatives, based on the total solid weight of the coating composition. Suitably, the coating composition may contain 4.5-10 wt% of benzoguanamine or its derivatives, based on the total solid weight of the coating composition.

[0081] The coating compositions of the present invention may optionally contain additional crosslinking materials. These additional crosslinking materials may be monomolecules, dimers, oligomers, (co)polymers, or mixtures thereof. The crosslinking agent may be a dimer or a trimer.

[0082] The additional crosslinking material may comprise any suitable crosslinking material. Suitable crosslinking materials are well known to those skilled in the art. Suitable crosslinking materials include, but are not limited to, the following: phenolic resins (or phenol-formaldehyde resins); amino plastic resins (or triazine-formaldehyde resins); amino resins; epoxy resins; isocyanate resins; β-hydroxy(alkyl)amide resins; alkylated urethane resins; polyacids; acid anhydrides; organometallic acid functional materials; polyamines; polyamides and combinations thereof. Suitably, the crosslinking material may comprise phenolic resins, isocyanate resins, or combinations thereof. Therefore, suitably, the coating composition may comprise polyester materials, benzoguanamine or its derivatives, and additional crosslinking materials (comprising phenolic resins and isocyanate resins).

[0083] Non-limiting examples of phenolic resins are those formed by the reaction of phenol with aldehydes or ketones, suitably the reaction of phenol with aldehydes, such as the reaction of phenol with formaldehyde or acetaldehyde, or even the reaction of phenol with formaldehyde. Non-limiting examples of phenols that can be used to form phenolic resins are phenol, butylphenol, xylenol, and cresol. General preparation of phenolic resins is described in "The Chemistry and Application of Phenolic Resins or Phenoplasts", Volume V, Part I, edited by Dr. Oldring; John Wiley and Sons / Cita Technology Limited, London, 1997. Suitably, phenolic resins are of the methyl phenolic resin (resol) type. "Methyl phenolic resin type" refers to resins formed in the presence of an alkaline (base) catalyst and optionally excess formaldehyde. Suitable examples of commercially available phenolic resins include, but are not limited to, those marketed under the trademark PHENODUR (RTM) from Cytec Industries, such as PHENODUR EK-827, PHENODUR VPR 1785, PHENODURPR 515, PHENODUR PR 516, PHENODUR PR 517, PHENODUR PR 285, PHENODUR PR 612, or PHENODUR PH 2024; resins marketed under the trademark BAKELITE (RTM) from Momentive, such as BAKELITE 6582 LB, BAKELITE 6535, BAKELITE PF 9989, or BAKELITE PF 6581; SFC 112 from Schenectady; DUREZ (RTM) 33356 from SHHPP; and ARALINK (RTM) from Bitrez. 40-852; or combinations thereof.

[0084] The coating composition may be substantially free of phenol, suitably substantially free of phenol, or suitably completely free of phenol. "Substantially free" means that the coating composition contains less than 1000 parts per million (ppm) of any of the aforementioned compounds or their derivatives. "Substantially free" means that the coating composition contains less than 100 ppm of any of the aforementioned compounds or their derivatives. "Completely free" means that the coating composition contains less than 20 parts per billion (ppb) of any compound or its derivative.

[0085] Non-limiting examples of isocyanate resins include, but are not limited to, the following: isophorone diisocyanates (IPDI), such as those marketed under the trademark DESMODUR (RTM) from Bayer, such as DESMODUR VP-LS 2078 / 2 or DESMODUR PL 340; or those marketed under the trademark VESTANAT (RTM) from Evonik, such as VESTANANT B1370, VESTANAT B118 6A, or VESTANAT B1358 A; blocked aliphatic polyisocyanates based on hexamethylene diisocyanate (HDI), such as those marketed under the trademark DESMODUR (RTM) from Bayer, such as DESMODUR BL3370 or DESMODUR BL3175 SN; and those marketed under the trademark DURANATE (RTM) from Asahi KASEI, such as DURANATE... MF-K60X, those marketed under the trademark TOLONATE (RTM) from Perstorp, such as TOLONATED2, or those marketed under the trademark TRIXENE (RTM) from Baxenden, such as TRIXENE-BI-7984 or TRIXENE 7981; or combinations thereof.

[0086] The additional crosslinking material may be present in the coating composition of the present invention in any suitable amount. The coating composition may contain 0.5-70 wt%, suitably 2.5-50 wt%, for example 5-30, or even 7.5-30 wt% of crosslinking material, based on the total solid weight of the coating composition. Suitably, the coating composition may contain 7.5-25 wt% of crosslinking material, based on the total solid weight of the coating composition.

[0087] The additional crosslinking material may include phenolic resins.

[0088] When present, phenolic resins may be present in the coating compositions of the present invention in any suitable amount. When present, the amount of phenolic resins in the coating composition may be 1-40 wt%, suitably 2.5-30 wt%, for example 5-20 wt%, or even 7.5-20 wt%, based on the total solid weight of the coating composition. Suitably, when present, the amount of phenolic resins in the coating composition may be 7.5-15 wt%, based on the total solid weight of the coating composition.

[0089] Therefore, according to another aspect of the present invention, a coating composition is provided, comprising:

[0090] Polyester materials, and

[0091] Crosslinked materials, which include phenolic resins and benzoguanidine or its derivatives,

[0092] The coating composition is substantially free of bisphenol A (BPA), bisphenol F (BPF), bisphenol A diglycidyl ether (BADGE), and bisphenol F diglycidyl ether (BFDGE), and the coating composition, when cured, has a flexibility of at least 20 mm, as determined by tensile and re-tensile testing methods in a 1% salt (NaCl) tap water solution at 130°C for 60 minutes, and a scratch resistance of at least 700 g, as determined according to ISO standard 1518-1:2011.

[0093] The additional crosslinking material may comprise an isocyanate resin.

[0094] The isocyanate resin, when present, can be present in the coating composition of the present invention in any suitable amount. The amount of the isocyanate resin in the coating composition can be 0.5-30 wt%, suitably 1-20 wt%, for example 1.5-10 wt%, based on the total solid weight of the coating composition. Suitably, the amount of the isocyanate resin in the coating composition can be 2-10 wt%, based on the total solid weight of the coating composition.

[0095] Therefore, according to another aspect of the present invention, a coating composition is provided, comprising:

[0096] Polyester materials, and

[0097] Crosslinked materials, comprising isocyanate resins and benzoguanamine or its derivatives,

[0098] The coating composition is substantially free of bisphenol A (BPA), bisphenol F (BPF), bisphenol A diglycidyl ether (BADGE), and bisphenol F diglycidyl ether (BFDGE), and the coating composition, when cured, has a flexibility of at least 20 mm, as determined by tensile and re-tensile testing methods in a 1% salt (NaCl) tap water solution at 130°C for 60 minutes, and a scratch resistance of at least 700 g, as determined according to ISO standard 1518-1:2011.

[0099] The isocyanate resin may be present in any suitable amount in the coating composition of the present invention. The coating composition may contain 0.5-30 wt%, suitably 1-20 wt%, for example 1.5-10 wt% isocyanate resin, based on the total solid weight of the coating composition. Suitably, the coating composition may contain 2-10 wt% isocyanate resin, based on the total solid weight of the coating composition.

[0100] The coating compositions according to the invention are substantially free of bisphenol A (BPA) and its derivatives. The coating compositions according to the invention may be substantially free of or completely free of bisphenol A (BPA) and its derivatives. Bisphenol A derivatives include, for example, bisphenol A diglycidyl ether (BADGE).

[0101] The coating compositions according to the invention are substantially free of bisphenol F (BPF) and its derivatives. The coating compositions according to the invention may be substantially free of or completely free of bisphenol F (BPA) and its derivatives. Derivatives of bisphenol F include, for example, bisphenol F diglycidyl ether (BPFG).

[0102] The aforementioned compounds or their derivatives, namely BPA, BPF, and their derivatives, may not have been intentionally added to the composition, but may be present in trace amounts due to unavoidable environmental contamination. Here, "substantially none" means that the coating composition contains less than 1000 parts per million (ppm) of any of the aforementioned compounds or their derivatives. "Substantially none" means that the coating composition contains less than 100 ppm of any of the aforementioned compounds or their derivatives. "Completely none" means that the coating composition contains less than 20 parts per billion (ppb) of any compound or its derivatives.

[0103] The coating composition of the present invention, upon curing, has a flexibility of at least 20 mm, determined by a tensile and re-stretch test method in a tap water solution of 1% salt (NaCl) at 130°C for 60 minutes. The flexibility of the coating composition of the present invention may be at least 22 mm, suitably at least 24 mm, for example at least 25 mm, determined by a tensile and re-stretch test method in a tap water solution of 1% salt (NaCl) at 130°C for 60 minutes.

[0104] Tensile and re-stretch tests are well-known to those skilled in the art for measuring the flexibility of coatings. The test is performed as follows: A 0.19 mm thickness and a tensile strength of 5.6 gsm (g / m²) are applied. -2A thin sheet of tin is coated with an 8gsm coating rod to form a coated panel. In the first step, the coated panel is placed under a stamping press, and a cylindrical cup with a height of 18mm and a diameter of 30mm is stamped from the panel. In the second step, the cylindrical cup is stretched into a cylindrical can with a height of 26mm and a diameter of 24mm. In the third step, the cylinder is treated in a 1% tap water solution of NaCl. The cylindrical can is placed in a container containing a simulant so that it is immersed in the solution. The container is then placed in an autoclave and treated at 130°C for 60 minutes. The coating damage and numerical grading on the outer wall of the resulting cylindrical can can be visually inspected. The height of the sidewall is 26 mm, and the height of the undamaged coating (mm) measured from the bottom of the sidewall is expressed as a number compared to 26. That is, a result of 20 mm indicates that the height of the undamaged coating over the entire 26 mm sidewall is 20 mm, meaning that the top 6 mm of the sidewall is damaged and the coating is observed to separate from the metal surface. A result of 26 mm indicates that the sidewall is completely undamaged, while a result of 0 mm indicates that the entire coating on the sidewall is damaged. The samples are evaluated by visual inspection immediately after the three-stage method is completed, without any further treatment. The stamping process and visual inspection are performed at 20°C.

[0105] The coating composition of the present invention has a scratch resistance of at least 700 g when cured, as measured according to ISO standard 1518-1:2011 ("Paints and varnishes – Determination of scratch resistance, Part 1: Constant load").

[0106] In this method, a scraping stylus loaded with a specific load is stretched over the coating at a constant speed. The minimum load required to cause coating penetration is measured according to Section 7.4 of ISO Standard 1518-1:2011. Typically, a coated metal panel is clamped in the panel holder of the scraping device, with the coated side facing upwards. The scraping stylus has a tungsten carbide ball tip with a diameter of 1 mm and is fixed to the load beam of the scraping device such that the stylus is perpendicular to the coated metal panel. Measurements are typically performed by stretching the stylus over the coating at a constant speed of 3-4 cm / s, starting with a load less than expected to cause coating penetration. The load on the scraping stylus is gradually increased (in increments of 100 g) until the coating penetrates, and the measurement is repeated. The weight in grams (g) required to cause coating penetration is recorded. Typically, this measurement is repeated three times.

[0107] Suitablely, the metal panel used in the ISO standard 1518-1:2011 method can be formed, for example, from tin-plated iron sheet or tin-free steel (TFS). Those skilled in the art will understand that the flexibility of the coating composition of the present invention is at least 700 g, which is measured according to ISO standard 1518-1:2011 when the metal panel used is formed from tin-plated iron sheet or tin-free steel (TFS).

[0108] When the metal panel used in the ISO standard 1518-1:2011 method is formed from tin-plated iron sheet, the flexibility of the coating composition is at least 700g, which is measured according to ISO standard 1518-1:2011.

[0109] When the metal panel used in the ISO standard 1518-1:2011 method is formed of tin-free steel (TFS), the flexibility of the coating composition may be at least 700g, suitably at least 1000g, for example at least 1200g, or even at least 1400g, as measured according to ISO standard 1518-1:2011.

[0110] The inventors have surprisingly and advantageously discovered that the coating compositions of the present invention, having the aforementioned combination of physical properties, can be widely used in a variety of different applications. For example, the inventors have surprisingly and advantageously discovered that the coating compositions of the present invention can be used on all parts of food and / or beverage containers, such as cans and / or parts used to manufacture such cans. Those skilled in the art will understand that it is necessary to apply typically different coatings to different parts of the can and / or parts used to manufacture such cans.

[0111] The coating composition according to the invention may further comprise a solvent. The coating composition may comprise a single solvent or a mixture of solvents. The solvent may comprise water, an organic solvent, a mixture of water and an organic solvent, or a mixture of organic solvents.

[0112] The organic solvent is suitably volatile enough to evaporate substantially completely from the coating composition during the curing process. As a non-limiting example, the curing method can be carried out by heating at 130-230°C for 1-15 minutes.

[0113] Suitable organic solvents include, but are not limited to, the following: aliphatic hydrocarbons such as mineral oil and high flash point naphtha; aromatic hydrocarbons such as benzene; toluene; xylene; solvent naphtha 100, 150, 200; those obtained under the trademark SOLVESSO (RTM) from Exxon-Mobil Chemical Company; alcohols such as ethanol; n-propanol; isopropanol; and n-butanol; ketones such as acetone; cyclohexanone; methyl isobutyl ketone; methyl ethyl ketone; esters such as ethyl acetate; butyl acetate; n-hexyl acetate; RHODIASOLV (RTM) RPDE (a mixture of succinate and adipate, commercially available from Rhodia); glycols such as butanediol; glycol ethers such as methoxypropanol; ethylene glycol monomethyl ether; ethylene glycol monobutyl ether and combinations thereof. The solvents, when present, may suitably be used in the coating composition in amounts of 1-90 wt%, suitably 1-80 wt%, for example 1-70 wt%, or even 5-70 wt%, based on the total solid weight of the coating composition. Suitablely, the amount of the solvent in the coating composition, when present, can be 10-60 wt%, based on the total solid weight of the coating composition.

[0114] The polyester material may be dissolved or dispersed in the solvent during and / or after its formation.

[0115] The coating compositions of the present invention may further comprise a catalyst. For example, any catalyst commonly used to catalyze the crosslinking reaction between polyester materials and crosslinking agents can be used. Suitable catalysts are well known to those skilled in the art. The catalyst may be a nonmetallic or metallic catalyst or a combination thereof. Suitable nonmetallic catalysts include, but are not limited to, the following: phosphoric acid; blocked phosphoric acid; CYCAT(RTM) XK 406 N (commercially available from Allnex); sulfuric acid; sulfonic acid; CYCAT 600 (commercially available from Allnex); NACURE(RTM) 5076 or NACURE 5925 (commercially available from King Industries); acidic phosphate ester catalysts such as NACURE XC 235 (commercially available from King Industries); and combinations thereof. Suitable metallic catalysts are well known to those skilled in the art. Suitable metal catalysts include, but are not limited to, the following: tin-containing catalysts, such as tris(2-ethylhexanoic acid) monobutyltin; zirconium-containing catalysts, such as KKAT(RTM) 4205 (commercially available from King Industries); titanate-based catalysts, such as tetrabutyl titanate (TnBT) (commercially available from Sigma Aldrich); and combinations thereof. When present, the catalyst can be used in the coating composition in any suitable amount. When present, the amount of catalyst can be 0.001-10 wt%, suitably 0.001-5 wt%, for example 0.01-5 wt%, or even 1-3 wt%, based on the total solid weight of the coating composition. Suitably, when present, the amount of catalyst can be 0.01-1.5 wt%, based on the total solid weight of the coating composition.

[0116] The coating compositions of the present invention may contain additional resin materials. Suitable additional resin materials are known to those skilled in the art. Suitable examples of additional resin materials include, but are not limited to, the following: polyester resins; acrylic resins; polyvinyl chloride (PVC) resins; alkyd resins; polyurethane resins; polysiloxane resins; epoxy resins or combinations thereof. Suitably, the additional resin material may contain polyvinyl chloride (PVC) resin.

[0117] The coating compositions of the present invention may contain other optional materials known in the field of coating formulation, such as colorants, plasticizers, abrasion-resistant particles, antioxidants, hindered amine light stabilizers, UV light absorbers and stabilizers, surfactants, flow control agents, thixotropic agents, fillers, organic co-solvents, reactive diluents, catalysts, abrasive carriers, lubricants, waxes, and other commonly used additives. It may be particularly desirable to use certain amounts of non-polymerizable surfactants in combination with polymerizable surfactants in the preparation of latex and / or latex-containing coatings.

[0118] As used herein, the term "colorant" means any substance that imparts color and / or other opacity and / or other visual effects to the composition. The colorant may be added to the coating in any suitable form, such as discrete particles, dispersions, solutions, and / or flakes. A single colorant or a mixture of two or more colorants may be used in the coatings of the present invention. Suitable colorants are listed in column 7, line 2 through column 8, line 65 of U.S. Patent No. 8,614,286, which is incorporated herein by reference. Particularly suitable for packaging coatings are those approved for food contact use, such as titanium dioxide; iron oxides such as iron oxide black; aluminum paste; aluminum powder such as aluminum flakes; carbon black; ultramarine blue; phthalocyanines such as phthalocyanine blue and phthalocyanine green; chromium oxides such as chromium oxide green; graphite filaments; iron yellow; quinacridone red; and combinations thereof, and those listed in Federal Regulations Code 178.3297, which is incorporated herein by reference.

[0119] The coating composition may contain aluminum paste, aluminum powder such as aluminum flakes, or a combination thereof. Suitably, the coating composition may contain aluminum paste.

[0120] When present, the colorant can be used in the coating composition in any suitable amount. When present, the amount of the colorant in the coating composition can be up to 90 wt%, for example up to 50 wt%, or even up to 10 wt%, based on the total solid weight of the coating composition.

[0121] Suitable lubricants are well known to those skilled in the art. Examples of suitable lubricants include, but are not limited to, carnauba wax and polyethylene-type lubricants. When present, the amount of lubricant in the coating composition may be at least 0.01 wt%, based on the total solid weight of the coating composition.

[0122] Surfactants may optionally be added to the coating composition to aid flow and substrate wetting. Suitable surfactants are well known to those skilled in the art. Suitably, when present, the surfactant is selected to be compatible with food and / or beverage container applications. Suitable surfactants include, but are not limited to, the following: alkyl sulfates (e.g., sodium dodecyl sulfate); ether sulfates; phosphate esters; sulfonates; and their various alkali metal salts, ammonium salts, amine salts; aliphatic alcohol ethoxylates; alkylphenol ethoxylates (e.g., nonylphenol polyether); salts and / or combinations thereof. When present, the amount of surfactant may be 0.01 wt% to 10 wt%, suitably 0.01 to 5 wt%, for example 0.01 to 2 wt%, based on the total solid weight of the coating composition.

[0123] The coating compositions of the present invention may be substantially free of, substantially free of, or completely free of dialkyltin compounds, including their oxides or other derivatives. Examples of dialkyltin compounds include, but are not limited to, the following: dibutyltin dilaurate (DBTDL); dioctyltin dilaurate; dimethyltin oxide; diethyltin oxide; dipropyltin oxide; dibutyltin oxide (DBTO); dioctyltin oxide (DOTO); or combinations thereof. "Substantially free of" means that the coating composition contains less than 1000 parts per million (ppm) of any of the above compounds or their derivatives. "Substantially free of" means that the coating composition contains less than 100 ppm of any of the above compounds or their derivatives. "Completely free of" means that the coating composition contains less than 20 parts per billion (ppb) of any of the above compounds or their derivatives.

[0124] The coating composition of the present invention can be applied as a single layer or as part of a multilayer system to a substrate or a portion thereof. The coating composition can be applied as a single layer. The coating composition can be applied to an uncoated substrate. For the avoidance of doubt, the uncoated substrate extends to a surface that has been cleaned prior to application. The coating composition can be applied as part of a multilayer system on top of another paint layer. For example, the coating composition can be applied on top of a primer. The coating composition can form an intermediate layer or a topcoat. The coating composition can be applied as the first layer in a multilayer system. Suitably, the coating composition can be applied as a base coat or primer. The second, third, fourth, etc., coatings can contain any suitable paint, such as those containing, for example, epoxy resins; polyester resins; polyurethane resins; polysiloxane resins; hydrocarbon resins; or combinations thereof. The second, third, fourth, etc., coatings can contain polyester resins. The second, third, fourth, etc., coatings can be liquid coatings or powder coatings, suitably powder coatings.

[0125] The coating composition can be applied to the substrate in one or more applications.

[0126] The coating composition can be applied as a base coat in a multi-coat system. The top coat can be a powder coating. The powder coating may contain polyester materials.

[0127] Therefore, according to another aspect of the present invention, a coating system is provided, comprising:

[0128] The primer coating composition comprises: a polyester material and benzoguanidine or its derivatives, and

[0129] Powder coating composition, comprising additional polyester material,

[0130] The coating system is substantially free of bisphenol A (BPA), bisphenol F (BPF), bisphenol A diglycidyl ether (BADGE), and bisphenol F diglycidyl ether (BFDGE), and the base coat coating composition has a flexibility of at least 20 mm when cured, as determined by tensile and re-tensile testing methods in a 1% salt (NaCl) tap water solution at 130°C for 60 minutes, and a scratch resistance of at least 700 g, as determined according to ISO standard 1518-1:2011.

[0131] The base coat coating composition is defined as described above in relation to the coating compositions of the present invention.

[0132] Powder coating compositions may be substantially free of bisphenol A (BPA), bisphenol F (BPF), bisphenol A diglycidyl ether (BADGE), and bisphenol F diglycidyl ether (BFDGE).

[0133] Suitable for use, the coating system is essentially free of bisphenol A (BPA), bisphenol F (BPF), bisphenol A diglycidyl ether (BADGE), and bisphenol F diglycidyl ether (BFDGE).

[0134] As used in this article, terms such as “powder” refer to materials in the form of solid particles, as opposed to materials in liquid form.

[0135] The powder coating composition of the present invention can be a thermosetting or thermoplastic powder coating composition. Suitably, the powder coating composition can be a thermoplastic coating composition.

[0136] The powder coating composition according to the invention comprises an additional polyester material. This additional polyester material may comprise reaction products of polyacids and polyols.

[0137] The additional polyester material can be formed from any suitable polyacid. Suitable examples of polyacids include, but are not limited to, the following: maleic acid; fumaric acid; itaconic acid; adipic acid; azelaic acid; succinic acid; sebacic acid; glutaric acid; decanoic acid; dodecanoic acid; phthalic acid; isophthalic acid; 5-tert-butylisophthalic acid; tetrachlorophthalic acid; tetrahydrophthalic acid; trimellitic acid; naphthalene dicarboxylic acid; naphthalene tetracarboxylic acid; terephthalic acid; hexahydrophthalic acid; methyl hexahydrophthalic acid; dimethyl terephthalate; cyclohexane dicarboxylic acid; chlorobenzyl anhydride; 1,3-cyclohexane dicarboxylic acid; 1,4-cyclohexane dicarboxylic acid; tricyclodecane polycarboxylic acid; inner methylene tetrahydrophthalic acid; inner ethyl hexahydrophthalic acid; cyclohexane tetracarboxylic acid; cyclobutane tetracarboxylic acid; esters and anhydrides of the aforementioned acids, and combinations thereof.

[0138] The additional polyester material can be formed from any suitable polyol. Suitable examples of polyols include, but are not limited to, the following: alkylene glycols such as ethylene glycol; propylene glycol; diethylene glycol; dipropylene glycol; triethylene glycol; tripropylene glycol; hexanediol; polyethylene glycol; polypropylene glycol and neopentyl glycol; hydrogenated bisphenol A; cyclohexanediol; propylene glycol, including 1,2-propanediol; 1,3-propanediol; butyl ethyl propylene glycol; 2-methyl-1,3-propanediol; and 2-ethyl-2-butyl-1,3-propanediol; butanediol, including 1,4-butanediol; 1, 3-Butanediol; and 2-ethyl-1,4-butanediol; pentanediol, including trimethylpentanediol and 2-methylpentanediol; cyclohexanediol; hexanediol, including 1,6-hexanediol; caprolactone diol (e.g., the reaction product of ε-caprolactone and ethylene glycol); hydroxyalkylated bisphenols; polyether diols, such as poly(oxytetramethylene)diol; trimethylolpropane; pentaerythritol; dipentaerythritol; trimethylolethane; trimethylolbutane; dimethylolcyclohexane; glycerol, etc., or combinations thereof.

[0139] The additional polyester material can be formed from a number of suitable molar ratios of polyacid:polyol. The polyacid:polyol molar ratio in this additional polyester material can be 20:1 to 1:20, suitably 10:1 to 1:10, for example 5:1 to 1:5, or even 2:1 to 1:2. Suitably, the polyacid:polyol molar ratio in this additional polyester material can be 1.2:1.2, or even essentially 1:1.

[0140] The additional polyester material may optionally be formed from additional monomers. Suitably, the additional polyester material may optionally include additional monomers selected from monoacids or monohydroxy alcohols or combinations thereof. Suitably, the optional additional monomers may be organic.

[0141] The additional polyester material may optionally be formed from another monoacid. As used herein, "monoacid" and similar terms refer to a compound having a carboxylic acid group, and include esters (wherein the acid group is esterified) or anhydrides of the monoacid. Suitable monoacids are organic monoacids.

[0142] The additional polyester material may optionally be formed from any suitable other monoacid. Suitable examples include, but are not limited to, the following: benzoic acid; cyclohexanecarboxylic acid; tricyclodecanecarboxylic acid; camphoric acid; benzoic acid; tert-butylbenzoic acid; C1-C 18 Aliphatic carboxylic acids such as acetic acid; propionic acid; butyric acid; hexanoic acid; oleic acid; linoleic acid; undecanoic acid; lauric acid; isononanoic acid; fatty acids; hydrogenated fatty acids of naturally occurring oils; esters and / or anhydrides of any of the aforementioned acids and combinations thereof.

[0143] The additional polyester material may optionally be formed from another monohydroxy alcohol. As used herein, "monohydroxy alcohol" and similar terms refer to compounds having one hydroxyl group. Suitably, the monohydroxy alcohol is an organic monohydroxy alcohol.

[0144] The additional polyester in the coating may have the same or different monomer composition (monomers and / or amounts thereof) as the base coat.

[0145] The additional polyester material may optionally be formed from any suitable other monohydroxy alcohol. Suitable examples include, but are not limited to, the following: benzyl alcohol; hydroxyethoxybenzene; methanol; ethanol; propanol; butanol; pentanol; hexanol; heptanol; dodecyl alcohol; octadecyl alcohol; oleyl alcohol; undecyl alcohol; cyclohexanol; phenol; phenyl alcohol; methylphenyl alcohol; cresol; monoethers of diols; halogenated or other substituted alcohols and combinations thereof.

[0146] The additional polyester material may include commercially available polyester materials. Suitable commercially available polyester materials include, but are not limited to, the following: those marketed under the trademark URALAC (RTM) from DSM, such as URALAC SN 800, URALAC SN 805, URALAC SN 808, URALAC SN 842, URALAC SN 859, URALAC SN 860, URALAC SN 905, URALAC 908, URALAC 989, or URALAC SN 978; those marketed under the trademark ITALKID (RTM) from Galstaff-Multiresine, such as ITALKID 212, ITALKID 218, ITALKID 226, ITALKID 228, ITALKID 231, or ITALKID 300; and those marketed under the trademark DOMOPOL (RTM) from Helios, such as DOMOPOL 5101, DOMOPOL 5102, DOMOPOL... 5111, DOMOPOL 5112, DOMOPOL 5113, DOMOPOL 5117, DOMOPOL 5132; those sold from Evonik under the trademark DYNAPOL (RTM), such as DYNAPOL LH 318, DYNAPOL LH818, DYNAPOL LH 820, DYNAPOL LH 823, DYNAPOL LH 830, DYNAPOL LH 833, DYNAPOL L912, DYNAPOL L 952, DYNAPOL L 206, DYNAPOL L 860, DYNAPOL P 1500, or DYNAPOL L600; those sold from DSM under the trademark URALAC (RTM), such as URALAC P1580, URALAC... 4215, URALAC5080, URALAC 5930 or URALAC 6024; those marketed under the trademark URADIL (RTM) from DSM, such as URADIL250, URADIL 255, URADIL 258, URADIL SZ 260 or URADIL SZ 262; those marketed under the trademark ITALESTER (RTM) from Galstaff-Multiresine, such as ITALESTER 217 or ITALESTER 218; those marketed under the trademark Griltex (RTM) from Ems Chemi, such as Griltex (RTM) D 2036E or Griltex D1573E;Those products marketed under the trademark Schaetti Melt (RTM) from Schaetti AG, such as Schaetti Melt 3521; and combinations thereof. Suitably, the additional polyester material may comprise those marketed under the trademark GRILLTEX (RTM) from EmsChemie, those marketed under the trademark Schaetti Melt (RTM) from Schaetti AG, or combinations thereof.

[0147] The additional polyester material can have any suitable glass transition temperature (Tg). The Tg of the additional polyester material can be -20°C to 120°C, suitably 0°C to 100°C, for example 10°C to 75°C, for example 15°C to 50°C, for example 15°C to 40°C, or even 15°C to 50°C.

[0148] The glass transition temperature (Tg) of the additional polyester material can be measured by any suitable method. Methods for measuring Tg are well known to those skilled in the art. Suitably, Tg is measured according to ASTM D6604-00 (2013) (“Standard Practice for Glass Transition Temperature of Hydrocarbon Resins by Differential Scanning Calorimetry”. Heat flux differential scanning calorimetry (DSC), sample pan: aluminum, reference: blank, calibration: indium and mercury, sample weight: 10 mg, heating rate: 20 °C / min).

[0149] The additional polyester material can have any suitable melting point (Tm). The Tm of the additional polyester can be 20-250°C, suitably 50-225°C, for example 100-200°C, or even 120-175°C. Suitably, the Tm of the additional polyester material can be 120-140°C, for example 125-135°C. Suitably, the Tm of the additional polyester material can be 140-170°C, for example 150-165°C.

[0150] The melting point of the additional polyester material can be measured by any suitable method. Methods for measuring Tm are well known to those skilled in the art. Suitably, the Tm is measured by differential scanning calorimetry (DSC) according to ASTM E794-06 (2012).

[0151] The additional polyester material may comprise a single polyester material or a combination of two or more polyester materials.

[0152] The powder coating composition may contain any suitable amount of additional polyester material. The powder coating composition may contain 10-99 wt%, suitably 20-90 wt%, for example 30-80 wt%, for example 40-75 wt%, or even 50-70 wt% of additional polyester material, based on the total solid weight of the powder coating composition. Suitably, the powder coating composition may contain 60-70 wt% of additional polyester material, based on the total solid weight of the powder coating composition.

[0153] The powder coating composition may contain at least 10 wt%, suitably at least 20 wt%, for example at least 30 wt%, for example at least 40 wt%, for example at least 50 wt%, or even at least 60 wt% of additional polyester material, based on the total solid weight of the powder coating composition. The powder coating composition may contain up to 99 wt%, suitably up to 90 wt%, for example up to 80 wt%, for example up to 75 wt%, or even up to 70 wt% of additional polyester material, based on the total solid weight of the powder coating composition. The powder coating composition may contain 10-90 wt%, suitably 20-90 wt%, for example 30-90 wt%, for example 40-90 wt%, for example 50-90 wt%, or even 60-90 wt% of additional polyester material, based on the total solid weight of the powder coating composition. The powder coating composition may contain 10-80 wt%, suitably 20-80 wt%, for example 30-80 wt%, for example 40-80 wt%, for example 50-80 wt%, or even 60-80 wt% of additional polyester material, based on the total solid weight of the powder coating composition. The powder coating composition may contain 10-75 wt%, suitably 20-75 wt%, for example 30-75 wt%, for example 40-75 wt%, for example 50-75 wt%, or even 60-75 wt% of additional polyester material, based on the total solid weight of the powder coating composition. The powder coating composition may contain 10-70 wt%, suitably 20-70 wt%, for example 30-70 wt%, for example 40-70 wt%, for example 50-70 wt%, or even 60-70 wt% of additional polyester material, based on the total solid weight of the powder coating composition.

[0154] The powder coating compositions of the present invention may contain other optional, well-known materials in the field of coating formulation, such as crosslinking agents, colorants, plasticizers, abrasion-resistant particles, antioxidants, hindered amine light stabilizers, UV light absorbers and stabilizers, surfactants, flow control agents, thixotropic agents, fillers, catalysts, abrasive carriers, lubricants, waxes, and other conventional additives. Those skilled in the art will understand that when the powder coating composition is a thermoplastic powder composition, the powder coating composition will not require crosslinking materials. Therefore, suitably, when the powder coating composition is a thermoplastic powder composition, the powder coating composition may be substantially free of crosslinking materials.

[0155] Suitable optional materials are as defined above in the description of the coating compositions relating to the first aspect of the invention, unless otherwise specified below. When present, suitable amounts of optional materials are as defined above in the description of the coating compositions relating to the first aspect of the invention, unless otherwise specified below.

[0156] The powder coating composition may contain any suitable colorant. Suitable colorants are as defined above in the description of coating compositions relating to the first aspect of the invention. Suitably, the powder coating composition may contain titanium dioxide.

[0157] The powder coating composition may contain any suitable filler. Suitably, the powder composition may contain barium sulfate and / or mica.

[0158] The powder coating composition may contain any suitable amount of colorant and / or filler. The coating composition may contain 1-90 wt%, suitably 5-70 wt%, for example 10-60 wt%, for example 20-50 wt%, or even 30-40 wt% pigment and / or filler, based on the total solid weight of the powder coating composition.

[0159] The powder coating composition may contain any suitable amount of colorant. The powder coating composition may contain 1-90 wt%, suitably 2.5-50 wt%, for example 5-30 wt%, or even 10-20 wt%, based on the total solid weight of the powder coating composition.

[0160] The powder coating composition may contain any suitable amount of filler. The powder coating composition may contain 1-90 wt%, suitably 5-50 wt%, for example 10-40 wt%, for example 15-30 wt%, or even 15-25 wt%, based on the total solid weight of the powder coating composition.

[0161] The coating system of the present invention is substantially free of bisphenol A (BPA) and its derivatives. The coating system may be substantially free of or completely free of bisphenol A (BPA) and its derivatives. Derivatives of bisphenol A include, for example, bisphenol A diglycidyl ether (BADGE). The coating system of the present invention is also substantially free of bisphenol F (BPF) and its derivatives. The coating system may be substantially free of or completely free of bisphenol F (BPF) and its derivatives. Derivatives of bisphenol F include, for example, bisphenol F diglycidyl ether (BPFG). The above-mentioned compounds or their derivatives may be unintentionally added to the coating system, but may be present in trace amounts due to unavoidable environmental contamination. "Substantially free" means that the coating system contains less than 1000 parts per million (ppm) of any of the above-mentioned compounds or their derivatives. "Substantially free" means that the coating system contains less than 100 ppm of any of the above-mentioned compounds or their derivatives. "Completely free" means that the coating system contains less than 20 parts per billion (ppb) of any of the above-mentioned compounds or their derivatives.

[0162] The powder coating compositions of the present invention can have any suitable average particle size. The average particle size of the powder coating compositions can be 1-1000 micrometers (µm), suitably 5-500µm, for example 5-250µm, or even 5-100µm. Particles having these sizes can be produced by any suitable method. Suitable methods are well known to those skilled in the art. Examples of suitable methods include, but are not limited to, cold milling and sieving methods.

[0163] The powder coating composition of the present invention can be prepared by any suitable method. For example, the powder coating composition can be prepared by first dry-mixing a polyester material and, if present, a crosslinking agent, pigment and / or filler, curing agent, and additives in a mixer. The mixer can be run for any suitable time. Suitably, the mixer can be run long enough to produce a homogeneous dry mix of the materials incorporated therein. This homogeneous dry mix can then be melt-mixed in an extruder, such as a twin-screw co-rotating extruder, operating in a temperature range of 80-140°C, suitably 100-125°C. The extrudate of the powder coating composition can be cooled and typically ground to the aforementioned average particle size.

[0164] The powder coating composition of the present invention is suitably a curable coating composition. As used herein, "curable coating composition" and similar terms refer to a coating composition that is initially in a powder state and ultimately in a state in which the coating composition has been transformed into a substantially continuous aggregated state.

[0165] The powder coating composition of the present invention can be cured by any suitable method. The powder coating composition can be cured by thermosetting or by chemical curing, suitably by thermosetting. When thermosetting, the powder coating composition can be cured at any suitable temperature. When thermosetting, the powder coating composition can be cured at temperatures of 50-350°C, suitably 100-320°C, for example 150-300°C or even 200-300°C.

[0166] The coating compositions and / or coating systems according to the invention can be applied to any suitable substrate. Examples of suitable substrates include, but are not limited to, food and / or beverage cans or components used to manufacture such cans. Examples of cans include, but are not limited to, two-piece cans, three-piece cans, etc. The coating compositions and / or coating systems can be applied to food and / or beverage cans having seams or welds along the can body. The coating compositions and / or coating systems of the invention can also be applied to containers for aerosol applications, such as, but not limited to, deodorant and hairspray containers.

[0167] Suitablely, the base coat composition is cured before the powder coating composition is applied.

[0168] The coating composition and / or coating system according to the invention can be applied to any suitable substrate. The coating composition and / or coating system can be applied to a metallic substrate. Examples of suitable metallic substrates include, but are not limited to, food and / or beverage packaging, components for making such packaging or monolithic aerosol cans and / or tubes. Suitably, the food and / or beverage packaging can be a can. Examples of cans include, but are not limited to, one or more of the following: two-piece cans, three-piece cans, etc. Suitable examples of monolithic aerosol cans and / or tubes include, but are not limited to, deodorant and hairspray containers. Monolithic aerosol cans and / or tubes can be aluminum monolithic aerosol cans and / or tubes.

[0169] Suitablely, the coating composition and / or coating system can be applied to food and / or beverage packaging or components used to make such packaging.

[0170] It is known to apply various pretreatment agents and coatings to packaging. Such treatments and / or coatings can be used, for example, in the case of metal cans, where treatment agents and / or coatings are used to delay or inhibit corrosion, provide a decorative coating, provide easy handling during the manufacturing process, etc. Coatings can be applied to the interior of such cans to prevent the contents from contacting the container metal. Contact between metal and food or beverage can, for example, cause corrosion of the metal container, which can then contaminate the food or beverage. This is particularly true when the contents of the can are acidic. Coatings applied to the interior of metal cans also help prevent corrosion in the headspace (the area between the product fill line and the can lid); corrosion in the headspace is particularly problematic with foods containing high salt content. Coatings can also be applied to the exterior of metal cans. Certain coating compositions and / or coating systems of the present invention are particularly suitable for use with coiled metal blanks, such as coiled metal blanks for manufacturing can ends (“can end blanks”), and blanks for manufacturing end caps and lids (“end cap / lid blanks”). Because the coatings designed for can end blanks and end cap / lid blanks are typically applied before the blanks are cut and the coiled metal blanks are punched out, they are generally flexible and stretchable. For example, such blanks are typically coated on both sides. The coated metal blank is then punched out. For the can end, serrated metal is then used for the "pull" opening, and the pull ring is then attached with a separately made pin. This end is then attached to the can body by crimping. A similar procedure is performed for "pull" can ends. For pull can ends, serrations around the lid allow for easy opening or removal of the lid from the can, typically by a pull tab. For end caps and lids, the end cap / lid blanks are typically coated, for example, by roll coating, and the caps or lids are punched out from the blanks; however, it is also possible to coat the end caps / lids after forming. Coatings for cans subjected to relatively harsh temperature and / or pressure requirements should also be resistant to bursting, corrosion, whitening, and / or blistering.

[0171] Therefore, the present invention further relates to a package which is at least partially coated with any of the aforementioned coating compositions and / or coating systems. “Packaging” is anything used to contain another article, particularly for transport from a manufacturer to a consumer, and subsequently stored by the consumer. Packaging is thus understood as something sealed to keep its contents from spoilage until opened by the consumer. Manufacturers often need to determine the duration in which food or beverages will not spoil, typically ranging from several months to several years. Therefore, the “packaging” of the present invention is distinguished from storage containers or baking utensils in which consumers would manufacture and / or store food; such containers would only maintain the freshness or integrity of the food article for a relatively short period. The packaging according to the invention can be made of metal or non-metal, such as plastic or laminate, and in any form. An example of suitable packaging is a laminated tube. Another example of suitable packaging is a metal can. The term “metal can” includes any type of metal can, container, or utensil or part thereof, which is sealed by the food and / or beverage manufacturer to minimize or eliminate spoilage of the contents until such packaging is opened by the consumer. An example of a metal can is a food can; the term "food can" is used herein to refer to a can, container, or any type of appliance or part thereof used to hold any type of food and / or beverage. The term "metal can" specifically includes food cans and specifically includes "can ends," including "EZ open ends," which are typically stamped from can end blanks and used with food and beverage packaging. The term "metal can" also specifically includes metal caps and / or lids such as bottle caps, screw-on caps, and lids of any size, handle caps, etc. The metal can can also be used to hold other items, including but not limited to personal care products, insecticide sprays, paints, and any other compounds suitable for aerosol can packaging. The can can include "two-piece cans" and "three-piece cans," as well as pull-out and iron one-piece cans; such one-piece cans are frequently used for aerosol products. Packaging coated according to the invention can also include plastic bottles, plastic tubes, laminates, and flexible packaging, such as those made of PE, PP, PET, etc. Such packaging is capable of holding, for example, food, toothpaste, personal care products, etc.

[0172] The coating composition and / or coating system can be applied to the interior and / or exterior of the packaging. The coating composition and / or coating system can also be applied as a rim coating to the bottom of the can. This rim coating serves to reduce friction to improve handleability during the continuous fabrication and / or processing of the can. Powder coatings can also be applied to the cap and / or lid; such applications can include, for example, protective varnishes applied before and / or after the formation of the cap / lid, and / or pigmented enamels applied post-to the cap, particularly those with grouted bottoms. Decorative can blanks can also be partially externally coated with the coatings described herein, and these decorative, coated can blanks are used to form various metal cans.

[0173] Metal coils, which have wide applications in many industries, are also substrates that can be coated according to the present invention. Coil coatings typically also contain colorants.

[0174] The coating composition and / or coating system according to the invention can be applied to at least a portion of a metal substrate. For example, when the coating composition and / or coating system is applied to a food and / or beverage can, it can be applied to at least a portion of the inner and / or outer surface of the food and / or beverage can.

[0175] The inventors have surprisingly and advantageously discovered that the coating compositions and / or coating systems of the present invention can be suitably applied to any part of the food and / or beverage can or to any component used in the manufacture of such a can. One advantage of the present invention is that the coating compositions and / or coating systems of the present invention have suitable properties that allow them to be applied to any part of the food and / or beverage can or to any component used in the manufacture of such a can. For example, the coating compositions and / or coating systems of the present invention can be applied equally to the can body and the easy-open end (EOE) of the can. For example, the coating compositions and / or coating systems of the present invention can be applied equally to the can body and the non-easy-open end (NEOE) of the can. Those skilled in the art will understand that different coatings are typically applied to these different parts of the can.

[0176] Suitablely, the coating system of the present invention can be applied to food and / or beverage cans having seams or welds along the can body.

[0177] The substrate can be formed of any suitable material. Suitable materials are well known to those skilled in the art. Suitable examples include, but are not limited to, the following: steel; tin-plated iron sheet; tin-plated iron sheet pretreated with a protective material such as chromium, titanium, titanate, or aluminum; tin-free steel (TFS); galvanized steel such as electroplated steel; aluminum; aluminum alloys; and combinations thereof. Suitably, the substrate can be formed of steel, tin-plated iron sheet, tin-plated iron sheet pretreated with a protective material such as chromium, titanium, titanate, or aluminum, tin-free steel (TFS), galvanized steel such as electroplated steel, and combinations thereof. Suitably, the substrate can be formed of tin-plated iron sheet, tin-free steel (TFS), or combinations thereof.

[0178] Suitable, the substrate can be formed from tin-plated iron sheet.

[0179] Suitablely, the substrate can be formed from tin-free steel (TFS).

[0180] The coating compositions and / or coating systems according to the present invention can be applied to a substrate by any suitable method. Those skilled in the art will understand that the primer and powder coating compositions of this coating system can be applied to the substrate independently of each other by any suitable method. Methods for applying the coating compositions and / or coating systems according to the present invention are well known to those skilled in the art. Suitable application methods for the coating compositions and / or coating systems of the present invention include, but are not limited to, the following: electrocoating; spraying; electrostatic spraying; dip coating; roller coating; brush coating, etc. Suitable application methods for the powder coating compositions according to the present invention include, but are not limited to, one or more of the following: spraying; roller coating; dip coating; and electrocoating, such as supercorona discharge. Suitably, the powder coating composition can be applied to a bulk aerosol can by supercorona discharge.

[0181] When the substrate is conductive, the powder coating composition is typically applied electrostatically. Electrostatic spraying generally involves extracting the powder coating composition from a fluidized bed and driving it through a corona field. The particles of the powder coating composition become charged as they pass through the corona field and are attracted to and deposited onto a grounded conductive substrate. As the charged particles begin to aggregate, the substrate becomes insulating, thus limiting further particle deposition. This insulating phenomenon typically limits the aggregated film of the deposited coating composition to a maximum of 250–300 µm, and in some cases 75–150 µm.

[0182] The coating compositions and / or coating systems of the present invention can be applied to any suitable dry film thickness. The coating compositions of the present invention can be applied to a dry film thickness of 4-40 micrometers (µm). The primer coating compositions of the coating system can be applied to a dry film thickness of 4-40 micrometers (µm). The powder coating compositions of the coating system can be applied to a dry film thickness of 5-100 micrometers (µm).

[0183] According to another aspect of the present invention, a food and / or beverage can is provided, wherein at least a portion thereof is coated with a coating composition comprising:

[0184] Polyester materials, and

[0185] Benzoguanidine or its derivatives,

[0186] The coating composition is substantially free of bisphenol A (BPA), bisphenol F (BPF), bisphenol A diglycidyl ether (BADGE), and bisphenol F diglycidyl ether (BFDGE), and the coating composition, when cured, has a flexibility of at least 20 mm, as determined by tensile and re-tensile testing methods and by treatment in a 1% salt (NaCl) tap water solution at 130°C for 60 minutes, and a scratch resistance of at least 700 g, as determined according to ISO standard 1518-1:2011.

[0187] According to another aspect of the present invention, a food and / or beverage can is provided, wherein at least a portion thereof is coated with a coating system comprising:

[0188] The base coat composition comprises a polyester material, and benzoguanamine or a derivative thereof, and

[0189] Powder coating composition comprising an additional polyester material,

[0190] The coating system is substantially free of bisphenol A (BPA), bisphenol F (BPF), bisphenol A diglycidyl ether (BADGE), and bisphenol F diglycidyl ether (BFDGE), and the coating composition, when cured, has a flexibility of at least 20 mm, as determined by tensile and re-tensile testing methods and by treatment in a 1% salt (NaCl) tap water solution at 130°C for 60 minutes, and a scratch resistance of at least 700 g, as determined according to ISO standard 1518-1:2011.

[0191] The coating compositions and / or coating systems according to the present invention may substantially lack, substantially lack, or completely lack dialkyltin compounds, including their oxides or other derivatives. Examples of dialkyltin compounds include, but are not limited to, the following: dibutyltin dilaurate (DBTDL); dioctyltin dilaurate; dimethyltin oxide; diethyltin oxide; dipropyltin oxide; dibutyltin oxide (DBTO); dioctyltin oxide (DOTO) or combinations thereof. "Substantially lack" means that the coating composition and / or coating system contains less than 1000 parts per million (ppm) of any of the above compounds or their derivatives. "Substantially lack" means that the coating composition and / or coating system contains less than 100 ppm of any of the above compounds or their derivatives. "Completely lack" means that the coating composition and / or coating system contains less than 20 parts per million (ppb) of any of the aforementioned compounds or their derivatives.

[0192] As used herein, unless otherwise expressly stated, all figures, such as those representing values, ranges, quantities, or percentages, may be interpreted as being prefixed with the word “about,” even if the term is not explicitly stated. Similarly, any numerical ranges described herein are intended to include all subranges within which they fall. The singular includes the plural, and vice versa. For example, while references herein include “a” first polyester material, “a” powder coating composition, “a” base coat composition, “a” isocyanate resin, “a” residual “the,” etc., one or more of each of these and any other components may be used. As used herein, the term “polymer” refers to both oligomers and homopolymers and copolymers, and the prefix “poly” refers to two or more. Terms such as “include,” “for example,” and “similar” indicate inclusion, for example, but not limitation. Furthermore, while the invention has been described as “comprising,” the methods, materials, and coating compositions detailed herein may also be described as “basically composed of” or “comprising.”

[0193] All the features contained herein can be combined with any of the above aspects and in any combination thereof.

[0194] To better understand the present invention and to show how its embodiments can be implemented, the following experimental data will now be mentioned as examples. Example

[0195] Coating composition

[0196] Example 1 of coating composition

[0197] Coating composition 1, which contains polyester material and benzoguanamine, is prepared according to the formulation in Table 1. All amounts are given in parts by weight (pbw) unless otherwise specified.

[0198] Add items 1-9 to a container equipped with a mixing system and mix at 1500 rpm. Mix items 10 and 11 separately, then add them to the container while stirring. Finally, add items 12 and 13 and thoroughly mix the contents of the container by stirring.

[0199] The dry weight of benzoguanidine in the coating composition of Example 1 is 5.65 wt%, based on the total dry solids weight of the coating composition of Example 1.

[0200] Example 2 of coating composition

[0201] Coating composition 2, which contains polyester material and benzoguanamine, is prepared according to the formulation in Table 2. All amounts are given in parts by weight (pbw) unless otherwise specified.

[0202] Comparative Coating Composition Example 1

[0203] Comparative coating composition 1, which contains polyester materials but no benzoguanamine, is prepared according to the formulation in Table 2. All amounts are given in parts by weight (pbw) unless otherwise specified.

[0204] Table 1 – Formulation of Coating Composition 1

[0205]

[0206] 1 A linear polyester is made of ethylene glycol, 2-methyl-1,3-propanediol, terephthalic acid and isophthalic acid, wherein Mn is about 10,000 g·mol and Tg is 56 °C.

[0207] 2 MAPRENAL(RTM) BF891, obtained from INEOS

[0208] 3 CYMEL(RTM)1123, obtained from Allnex

[0209] 4 DUREZ (RTM) 33356, obtained from Sumitomo

[0210] 5 CURAPHEN (RTM) 40-852, obtained from Bitrez

[0211] 6 VESTANAT(RTM) EP-B1186A, obtained from Evonik

[0212] 7 xylene

[0213] 8 BYK088, obtained from BYK-Chemie

[0214] 9 Lanolin wax (15wt% solution)

[0215] 10 NACURE (RTM) 5925, a blocked acid catalyst, is obtained from King Industries Inc.

[0216] 11 2-Butoxyethyl acetate

[0217] 12 Butyl acetate

[0218] Table 2 – Formulations of Coating Composition 2 and Comparative Coating Composition 1

[0219]

[0220] 1 DYNAPOL(RTM)LH318, obtained from Evonik

[0221] 2 CYMEL(RTM)1123, obtained from Allnex

[0222] 3 DUREZ (RTM) 33356, obtained from Sumitomo

[0223] 4 CURAPHEN (RTM) 40-852, obtained from Bitrez

[0224] 5 VESTANAT(RTM) EP-B1186A, obtained from Evonik

[0225] 6 BYK088, obtained from BYK-Chemie

[0226] 7 CERAFAK(RTM)8RC7301, obtained from BYK-Chemie

[0227] 8 NACURE (RTM) 5925, a blocked acid catalyst, is obtained from King Industries Inc.

[0228] 9 TIBKAT(RTM) 620 (10% solution), obtained from TIB-Chemicals

[0229] 10 RHODIASOLV(RTM)RPDE, obtained from Rhodia

[0230] 11 xylene

[0231] 12 Diisobutyl ketone (DIBK)

[0232] 13 DOWANOL (RTM) PM, obtained from DOW Chemical Company

[0233] Example 1 of Coating Composition

[0234] Coating composition 1 is prepared according to the formulation in Table 3. All amounts are given in parts by weight (pbw) unless otherwise specified.

[0235] Items 1a and 1b were added to a stirred reactor and heated. Item 1 was then added to the reaction mixture. The reaction mixture was heated to 80°C with stirring until the polyester resin was completely dissolved. Once dissolved, the reaction mixture was cooled to 25–30°C. Items 2 and 3 were then homogenized in a rotary drum and used to adjust the viscosity of the reaction mixture during the addition of item 4. Item 4 was slowly added with sufficient stirring to obtain a powder dispersion in which aggregates were no larger than 30 µm.

[0236] When the temperature of the reaction mixture has decreased to a relevant temperature of 30-40°C, add items 7 and 8 to the reaction mixture with stirring. Then homogenize items 9 and 10 and add them to the reaction mixture. Increase stirring to disperse the wax. Premix items 11 and 12 and then add them with stirring. Adjust the viscosity to 75-85 s at 25°C by adding item 13 according to ISO 6. Then filter the reaction mixture through a 10-50 µm filter.

[0237] Table 3 – Formulation of Coating Composition 3

[0238]

[0239] 1 DYNAPOL(RTM)L952, obtained from Evonik

[0240] 2 SOLVESSO (RTM) 100

[0241] 3 DOWANAL(RTM)PM (methoxypropanol), obtained from Dow

[0242] 4 Butylene glycol

[0243] 5 VINNOL (RTM) P70, obtained from Wacker Chemie

[0244] 6 RPDE, a mixture of succinate, adipate, and fumarate.

[0245] 7 PR516, obtained from Cytec

[0246] 8 DEHYSOL(RTM)D82 H, obtained from BASF

[0247] 9 LUBAPRINT(RTM)121 / H, obtained from Bader-Munzig

[0248] 10 TF1780x0.1, a PTFE-modified polyethylene wax

[0249] 11 H3PO4

[0250] 12 Methoxypropanol

[0251] Example 4 of Coating Composition

[0252] Coating composition 4 is a commercially available BPA Ni powder side stripe, obtained from Valspar as VECODUR(RTM)VP1091.

[0253] Comparative Coating Composition Example 2

[0254] Comparative coating composition 2 is a commercially available polyester-based paint obtained from Metlac SpA, containing a combination of polyester and phenolic materials.

[0255] Comparative Coating Composition Example 3

[0256] Comparative coating composition 3 is a commercially available polyester-based paint sourced from PPG Industries, containing a combination of polyester and phenolic materials.

[0257] Comparative Coating Composition Example 4

[0258] Comparative coating composition 4 is a commercially available organosol paint, obtained from PPG Industries, containing a combination of polyvinyl chloride organosol and phenolic materials.

[0259] Comparative Coating Composition Example 5

[0260] Comparative coating composition 5 is a commercially available epoxy gold paint, obtained from PPG Industries, containing a combination of epoxy materials, phenolic materials, and melamine-formaldehyde materials.

[0261] Metal substrate

[0262] The coating is applied to a series of metal substrates as follows.

[0263] Tinplate panel: The coated panel is prepared by coating a tinplate substrate using a wire-wound experimental rod. The coating is applied as a single layer (i.e., one coating) or as two layers (i.e., two coatings). The dry film weight of each coating is 9-10 g / m². 2 (gsm). After application, dry the panel at 200°C for 10 minutes.

[0264] Tin-plated iron sheet: Coated tin-plated iron sheet is prepared by coating tin-plated iron sheet using a roller coater. The coating is applied as a single layer (i.e., one coat) or as two layers (i.e., two coats). Unless otherwise indicated, the dry film weight of each coat is 9-10 g / m². 2 (gsm). After coating, the sheet is dried at 200°C for 10 minutes. The test is performed on tin-plated iron sheets prepared by this method, or on cans subsequently formed into non-easy-open (NEOE), easy-open (EOE), or deep-drawn cans, and the test is performed on these components.

[0265] The coating performance was then tested using the following method. The results are shown in Table 4-8.

[0266] Test methods

[0267] Scratch Resistance: This test was performed according to ISO standard 1518-1:2011. The scratching device (powered with 200 / 250V AC, 50Hz) has an arm supporting a scratching stylus and is configured to allow the arm to slide across the test panel at a constant speed of 3-4 cm / s. The scratching stylus has a counterweight and a tungsten carbide ball with a diameter of 1 mm. The coated panel is up to 127 mm high and 1.65 mm thick. The coated panel is fixed to the device, and the scratching stylus with a weight load of up to 2000 g is stretched across the panel at a speed of 3-4 cm / s. The measurement was performed using progressively increasing loads in 100 g increments. The coating penetration of the panel was visually inspected.

[0268] Record the weight in grams (g) at which coating penetration occurs (e.g., coating failure).

[0269] Flexible-stretching and re-stretching: The coated panel is placed under a stamping press, and a can with dimensions of 18mm x 30mm (height x diameter) is stamped. It is then placed in a second machine, and the can is transformed into a deep-drawn shape with dimensions of 26mm x 24mm (height x diameter). The formed can is then treated in a 1% NaCl solution and various other simulants. The formed can is placed in a container containing simulants, such that it is immersed in the solution. The container is then placed in an autoclave and treated at 130°C for 60 minutes. In addition to the 1% NaCl solution, the common solutions are tap water and 1% lactic acid in the tap water. After processing, the can is visually inspected, and the non-wear portion of the coating composition along the straight edge of the can is measured. This value is recorded in millimeters (mm), with a maximum value of 26mm.

[0270] Migration: Surface migration was measured using an ALTEK 9505 activity / lubricity tester. The sample was mounted into the machine, and the testing sequence was initiated according to the manufacturer's instructions. The coefficient of friction determined from this testing sequence was quoted from the electronic analog instrument readings.

[0271] Wedge Bending Test (WBT): A 10cm x 4cm coated panel was bent on a 6mm steel rod to form a U-shaped strip 10cm long and 2cm wide. This U-shaped strip was then placed on a metal block and fitted into a conical recess. A 2kg weight was dropped from a height of 60cm onto the recess containing the U-shaped strip to form a wedge shape. The test piece was then immersed in a copper sulfate (CuSO4) solution acidified with hydrochloric acid (HCl) for 2 minutes, followed by rinsing with tap water. The sample was then carefully dried by blotting out any residual water with tissue paper. The length of the coating without any cracks was measured. Results are reported in mm. The wedge bending test was performed three times, and the average value was recorded.

[0272] Treatment with different simulants: Coated panels cut into 10cm x 5cm sections were placed in a container containing simulants, with half of the panels submerged in the solution. The container was then placed in an autoclave and treated at 130°C for 60 minutes. The common solutions were tap water, a 1% saline solution, and a 1% lactic acid solution. After this time, the panels were visually inspected for whitening (i.e., coating whitening), blistering, discoloration, and loss of adhesion. Grade 0 corresponds to excellent film appearance with no detectable corrosion. Grade 5 corresponds to complete film corrosion.

[0273] Adhesion is checked post-treatment. The coating is cross-stitched and checked for removal with tape. Grade 0 corresponds to good adhesion, with no coating removal, and Grade 5 represents complete loss of adhesion.

[0274] Porosity: Porosity values ​​directly relate to the surface of metal that is not properly covered by the coating. For this purpose, porosity was measured using a Sencon enamel classifier in 4-second mode with an electrolyte consisting of 1000g deionized water, 5g sodium chloride, 10g potassium ferrocyanide, and 1.43g sodium dioctyl sulfonate solution at a concentration of 65%. If uncoated metal was present, a current was passed through, and the reading was displayed in milliamperes (mA). The target was 0.0 mA, which corresponds to excellent metal coverage. For in-can porosity, the same measurement can be performed using, for example, a Manfred Kuhnke classifier.

[0275] Sulfur contamination: Sulfur contamination corresponds to the blackening that occurs when cans contain certain food items such as cracked peas, sardines, tuna, or pet food. The cracked peas are prepared in water. The expanded peas are then placed in cans coated with an evaluated varnish and treated at 130°C for 1 hour. The cans are opened after approximately 12 hours. The results are visually evaluated and graded on a 0-5 scale.

[0276] Powder coating adhesion: The powder coating composition was manually applied to panels coated with paint composition 2 and control paint composition 1. The powder coating composition was then cured at 295°C for 45 seconds. The coated panels were then cut along the edges of the powder coating composition, and the adhesion of the powder coating composition to the cut edges of the base coat paint composition was evaluated based on the level of peeling from the base coat paint composition. Results were visually evaluated at time = 0 and time = 24 hours. Grade 4 was the highest grade, indicating the minimum amount of peeling, and 1 was the lowest grade, indicating the maximum amount of peeling.

[0277] Feathering: The goal of this test is to examine the coating's resistance to the opening of a food can in an easy-open situation. Indeed, the coating must adhere completely to the substrate, even after the lid has been cut when opened with an easy-open system. Delamination is measured in millimeters and corresponds to the uncovered substrate at the cut edge created by the lid opening.

[0278] Table 4 – Results on tin-plated iron sheet panels

[0279]

[0280] Table 5 – Results on tin-plated iron sheets

[0281]

[0282] Table 6 – Results on tinplate sheets formed as non-easy-open (NEOE) cans

[0283]

[0284] Table 7 - Results on Easy Start (EOE)

[0285]

[0286] Table 8 – Results of Powder Strip Adhesion

[0287]

[0288] The results confirm that the coating compositions and / or systems according to the present invention perform well, or are superior to those in the comparative examples. Furthermore, the coating compositions and / or systems of the present invention exhibit good performance on all substrates.

[0289] Concerning all papers and documents submitted concurrently with or prior to this application and publicly available to the public, the contents of all such papers and documents are incorporated herein by reference.

[0290] All features disclosed in this application (including any accompanying claims and abstract), and / or all steps of any disclosed method, may be combined in any combination, except that at least some of such features and / or steps are mutually exclusive combinations.

[0291] Each feature disclosed in this application (including any accompanying claims and abstract) may be replaced by an alternative feature serving the same, equivalent, or similar purpose, unless otherwise expressly stated. Therefore, unless otherwise expressly stated, each disclosed feature is merely one example of an equivalent or similar feature in a general series.

[0292] This invention is not limited to the details of the foregoing embodiments. The invention extends to any new feature or combination of features disclosed in this application (including any accompanying claims and abstract), or to any new step or combination of steps in any disclosed method.

Claims

1. A coating composition comprising: Based on the total solids weight of 40-95 wt% polyester material in the coating composition, Based on the total solids weight of the coating composition, up to 30 wt% of benzoguanidine or its derivatives, and The additional crosslinking material comprises 0.5-30 wt% of phenolic resin and isocyanate resin based on the total solid weight of the coating composition; The coating composition also contains a non-metallic catalyst; The coating composition is substantially free of bisphenol A (BPA), bisphenol F (BPF), bisphenol A diglycidyl ether (BADGE), and bisphenol F diglycidyl ether (BFDGE), and the coating composition, when cured, has a flexibility of at least 20 mm, as determined by tensile and re-tensile testing methods in a 1% salt (NaCl) tap water solution at 130°C for 60 minutes, and a scratch resistance of at least 700 g, as determined according to ISO standard 1518-1:2011.

2. The coating composition according to claim 1, wherein the polyester material is formed from terephthalic acid, isophthalic acid, sebacic acid, or a combination thereof.

3. The coating composition according to claim 1 or 2, wherein the polyester material is formed from 2,2'-dimethyl-1,3-propanediol (neopentylene glycol), 1,4-butanediol, 2-methyl-1,3-propanediol, ethylene glycol, 1,2-propanediol, 1,6-hexanediol, or a combination thereof.

4. The coating composition according to claim 1, wherein the polyester material comprises the reaction product of the following components: (i) 1,2-Propanediol, (ii) terephthalic acid, and (iii) Molecular weight increasers The number-average molecular weight (Mn) of the polyester material is at least 6100 Da and the glass transition temperature (Tg) is at least 80 °C.

5. The coating composition according to claim 4, wherein the molecular weight increaser (iii) comprises a polyacid, a polyol, or a combination thereof; Polyacids include diacids of general formula (I): Equation (I) Each R independently represents hydrogen or an alkyl, alkenyl, alkynyl, or aryl group; n = 0 or 1; where X represents a bridging group selected from the following: alkylene; alkenyl; alkynyl; aryl; where the bridging group between the -COOR groups is C1 or C2; The hydroxyl groups of the polyols therein are linked via C1-C3 alkylene groups.

6. The coating composition according to any one of claims 1-5, wherein the coating composition comprises at least 4.5 wt% of benzoguanidine or its derivatives, based on the total solid weight of the coating composition.

7. A coating system comprising: The base coat coating composition contains Based on the total solids content of the coating composition, 40-95 wt% polyester material, Based on the total solids weight of the coating composition, up to 30 wt% of benzoguanidine or its derivatives and The additional crosslinking material comprises 0.5-30 wt% of phenolic resin and isocyanate resin based on the total solid weight of the coating composition; The coating composition also contains a non-metallic catalyst; and Powder coating composition comprising polyester material, The coating system is substantially free of bisphenol A (BPA), bisphenol F (BPF), bisphenol A diglycidyl ether (BADGE), and bisphenol F diglycidyl ether (BFDGE), and the base coat coating composition has a flexibility of at least 20 mm when cured, as determined by tensile and re-tensile testing methods in a 1% salt (NaCl) tap water solution at 130°C for 60 minutes, and a scratch resistance of at least 700 g, as determined according to ISO standard 1518-1:2011.

8. The coating system of claim 7, wherein the primer coating composition is a coating composition according to any one of claims 2-6.

9. The coating system according to claim 7 or claim 8, wherein the coating system is applied to food and / or beverage cans, or along the seams or welds of the can body.

10. A food and / or beverage can, wherein at least a portion thereof is coated with a coating composition comprising the following components: Based on the total solids weight of 40-95 wt% polyester material in the coating composition, Based on the total solids weight of the coating composition, up to 30 wt% of benzoguanidine or its derivatives, and The additional crosslinking material comprises 0.5-30 wt% of phenolic resin and isocyanate resin based on the total solid weight of the coating composition; The coating composition also contains a non-metallic catalyst; and The coating composition is substantially free of bisphenol A (BPA), bisphenol F (BPF), bisphenol A diglycidyl ether (BADGE), and bisphenol F diglycidyl ether (BFDGE), and the coating composition, when cured, has a flexibility of at least 20 mm, as determined by tensile and re-tensile testing methods in a 1% salt (NaCl) tap water solution at 130°C for 60 minutes, and a scratch resistance of at least 700 g, as determined according to ISO standard 1518-1:2011.

11. A food and / or beverage can, wherein at least a portion thereof is coated with a coating system comprising the following components: The base coat composition comprises Based on the total solids content of the coating composition, 40-95 wt% polyester material, Based on the total solids weight of the coating composition, up to 30 wt% of benzoguanidine or its derivatives and The additional crosslinking material comprises 0.5-30 wt% of phenolic resin and isocyanate resin based on the total solid weight of the coating composition; The coating composition also contains a non-metallic catalyst; and Powder coating composition comprising polyester material, The coating system is substantially free of bisphenol A (BPA), bisphenol F (BPF), bisphenol A diglycidyl ether (BADGE), and bisphenol F diglycidyl ether (BFDGE), and the base coat coating composition has a flexibility of at least 20 mm when cured, as determined by tensile and re-tensile testing methods in a 1% salt (NaCl) tap water solution at 130°C for 60 minutes, and a scratch resistance of at least 700 g, as determined according to ISO standard 1518-1:2011.

12. Molecular weight increaser (iii), comprising a diacid of general formula (I): Equation (I) Each R independently represents hydrogen or alkyl, alkenyl, alkynyl, or aryl; n = 0 or 1; where X represents a bridging group selected from the following: alkylene; alkenyl; alkynyl; aryl; where the bridging group between the -COOR groups is C1 or C2.

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