Coating compositions comprising tmcd polyester and modified polyester

Abstract

The present invention relates to coating compositions based on polyesters containing 2,2,4,4-tetramethyl-1,3-cyclobutanediol (TMCD) and modified polyester polyols. Coatings based on this polyester blend are able to provide a good balance of desirable coating properties such as solvent resistance, acid resistance, dry distillate resistance, craze resistance and flexing ability for metal packaging applications.

Description

Technical Field

[0001] This application generally relates to chemistry. In particular, this application relates to polyester compositions. More specifically, this application relates to polyester compositions containing 2,2,4,4-tetramethyl-1,3-cyclobutanediol (TMCD) for coating metals. Background Technology

[0002] Metal containers are commonly used for food and beverage packaging. Containers are typically made of steel or aluminum. Prolonged contact between the metal and the filling product can lead to corrosion of the container. To prevent direct contact between the filling product and the metal, a coating is usually applied to the inside of food and beverage cans. For effectiveness, this coating must possess sufficient properties to protect the packaged product, such as adhesion, corrosion resistance, chemical resistance, flexibility, contamination resistance, and hydrolytic stability. Furthermore, the coating must be able to withstand the processing conditions during can manufacturing and food sterilization. Coatings based on a combination of epoxy and phenolic resins are known to provide a good balance of the required properties and are the most widely used. Some industrial sectors are moving away from food contact polymers prepared with bisphenol A (BPA) (the basic structural unit of epoxy resin). Therefore, there is a need for BPA-free coatings for inner can coatings.

[0003] Polyester resins are of particular interest in the coatings industry as alternatives to epoxy resins because they possess comparable properties, such as flexibility and adhesion. It is known to those skilled in the art that the crosslinking between common polyesters and phenolic resins is too poor to provide sufficient properties for in-can coatings. Specifically, conventional polyesters with hydroxyl functional groups are not sufficiently reactive with phenolic resins under curing conditions to provide adequate crosslinking density, resulting in coatings lacking good solvent resistance.

[0004] 2,2,4,4-Tetramethyl-1,3-cyclobutanediol (TMCD) is an alicyclic compound used as a diol component in the preparation of polyesters. Thermoplastics based on TMCD polyesters exhibit excellent impact resistance due to the unique structure of TMCD. TMCD also provides good hydrolytic stability to polyesters due to its secondary hydroxyl functional groups. Both of these properties are highly desirable in thermosetting coatings.

[0005] TMCD-based polyester coatings have been considered as an alternative to epoxy resins for inner tank coatings. Existing work involves coating systems based on slightly crosslinked, high-Tg, medium-molecular-weight TMCD polyesters to withstand the processing conditions of tank manufacturing. However, these systems have been found to have drawbacks in some desired properties, such as corrosion resistance, distillation resistance, and crack (microcrack) resistance. Higher crosslinking can lead to improved coating properties, such as corrosion resistance, acid resistance, stain resistance, and distillation resistance. However, these coatings tend to have poor flexibility, which adversely affects crack resistance and flexural strength during processing. Therefore, there remains a need to find a suitable TMCD-containing polyester polyol composition that can provide a good balance of coating properties required for metal packaging applications. Summary of the Invention

[0006] A coating composition for metal packaging applications, comprising:

[0007] a. 2,2,4,4-Tetramethyl-1,3-cyclobutanediol (TMCD) polyester, which is a reaction product of a monomer, said monomer comprising:

[0008] i. Based on the total number of moles in (a)(i-iv), the amount of TMCD is 35 mol%-80 mol%.

[0009] ii. Based on the total moles of (a)(i-iv), 20 mol%–65 mol% of 1,4-cyclohexanediethanol (1,4-CHDM),

[0010] iii. Based on the total molar number of (a)(i-iv), the amount of diols that are different from TMCD and different from 1,4-CHDM, ranging from 0 mol% to 25 mol%.

[0011] iv. Based on the total moles of (a)(i-iv), 0 mol%-5 mol% of trimethylolpropane (TMP),

[0012] v. Based on the total number of moles of (a)(v-vi), 90 mol%-100 mol% of aromatic diacids.

[0013] vi. Based on the total number of moles of (a)(v-vi), aliphatic diacids in amounts ranging from 0 mol% to 10 mol%.

[0014] b. A modified polyester, which is a reaction product of a monomer, said monomer comprising:

[0015] i. Based on the total number of moles in (b)(i-iii), 30 mol%-55 mol% of cyclic diols,

[0016] ii. Based on the total moles of (b)(i-iii), 30 mol%-67 mol% of 2-methyl-1,3-propanediol (MP diol),

[0017] iii. Based on the total number of moles in (b)(i-iii), 3 mol%-20 mol% of trimethylolpropane (TMP),

[0018] iv. The total molar amount of base (b)(iv-v), 55 mol% to 85 mol% of terephthalic acid (TPA) or isophthalic acid (IPA) or a mixture thereof,

[0019] v. Based on the total molar number of (b)(iv-v), the amount of aliphatic diacid is 15 mol%-45 mol%.

[0020] c. One or more crosslinking agents selected from the group consisting of: methyl phenolic resins, isocyanates, and amino resin crosslinking agents.

[0021] The TMCD polyester has a glass transition temperature (Tg) of 60 to 110°C, an acid value of 0 to 8 mg KOH / g, a hydroxyl value of 3 to 25 mg KOH / g, a number-average molecular weight of 5,000 to 20,000 g / mol, and a weight-average molecular weight of 10,000 to 100,000 g / mol; the modified polyester has a Tg of 20 to 50°C, an acid value of 0 to 10 mg KOH / g, a hydroxyl value of 30 to 60 mg KOH / g, a Mn of 2,000 to 10,000 g / mol, and a Mw of 10,000 to 150,000 g / mol; and the coating has a solvent resistance of greater than 70 MEK bi-friction as measured by ASTM D7835, and a wedge bending resistance (% qualified) of 60-100 as measured by ASTM D3281.

[0022] A coating composition for metal packaging applications, comprising:

[0023] a. Based on the total weight of (a), (b), (c), and (d), 30-40 wt% of a 2,2,4,4-tetramethyl-1,3-cyclobutanediol (TMCD) polyester, which is the reaction product of a monomer comprising:

[0024] i. Based on the total number of moles in (a)(i-iv), the amount of TMCD is 35 mol%-80 mol%.

[0025] ii. Based on the total moles of (a)(i-iv), 20 mol%–65 mol% of 1,4-cyclohexanediethanol (1,4-CHDM),

[0026] iii. Based on the total molar number of (a)(i-iv), the amount of diols that are different from TMCD and different from 1,4-CHDM, ranging from 0 mol% to 25 mol%.

[0027] iv. Based on the total moles of (a)(i-iv), 0 mol%-5 mol% of trimethylolpropane (TMP),

[0028] v. Based on the total number of moles of (a)(v-vi), 90 mol%-100 mol% of aromatic diacids.

[0029] vi. Based on the total number of moles of (a)(v-vi), aliphatic diacids in amounts ranging from 0 mol% to 10 mol%.

[0030] b. Based on the total weight of (a), (b), (c), and (d), 30-40 wt% of a modified polyester, which is a reaction product of a monomer comprising:

[0031] i. Based on the total number of moles in (b)(i-iii), 30 mol%-55 mol% of cyclic diols,

[0032] ii. Based on the total moles of (b)(i-iii), 30 mol%-67 mol% of 2-methyl-1,3-propanediol (MP diol),

[0033] iii. Based on the total number of moles in (b)(i-iii), 3 mol%-20 mol% of trimethylolpropane (TMP),

[0034] iv. The total molar amount of base (b)(iv-v), 55 mol% to 85 mol% of terephthalic acid (TPA) or isophthalic acid (IPA) or a mixture thereof,

[0035] v. Based on the total molar number of (b)(iv-v), the amount of aliphatic diacid is 15 mol%-45 mol%.

[0036] c. Based on the total weight of (a), (b), and (c), 15-30 wt% of methyl phenolic resin, and

[0037] d. Based on the total weight of (a), (b), and (c), 5-15 wt% of isophorone diisocyanate (IPDI),

[0038] The TMCD polyester has a glass transition temperature (Tg) of 60 to 110°C, an acid value of 0 to 8 mg KOH / g, a hydroxyl value of 3 to 25 mg KOH / g, a number-average molecular weight (Mn) of 5,000 to 20,000 g / mol, and a weight-average molecular weight (Mw) of 10,000 to 100,000 g / mol; the modified polyester has a Tg of 20 to 50°C, an acid value of 0 to 10 mg KOH / g, a hydroxyl value of 30 to 60 mg KOH / g, a Mn of 2,000 to 10,000 g / mol, and a Mw of 10,000 to 150,000 g / mol; and the coating has a solvent resistance of greater than 70 MEK bi-friction as measured by ASTM D7835, and a wedge bending resistance (% qualified) of 60-100 as measured by ASTM D3281. Detailed Implementation

[0039] Throughout this specification and the following claims, numerous terms will be used, which will be defined to have the following meanings.

[0040] "Alcohol" refers to a chemical containing one or more hydroxyl groups.

[0041] "Aldehyde" refers to a chemical containing one or more -C(O)H groups.

[0042] "Acyclic" refers to compounds or molecules that do not have atomic rings in their structure.

[0043] "Aliphatic" refers to compounds with non-aromatic structures.

[0044] "Dicarboxylic acid" refers to a compound that has two carboxyl functional groups.

[0045] Numerical values ​​can be expressed as “about” or “approximately” to a given number. Similarly, a range can be expressed herein as “about” to a particular value and / or “about” to another particular value. When such a range is expressed, the other side includes from one particular value and / or to another particular value. Similarly, when a numerical value is expressed as an approximation using the antecedent “about”, it should be understood that a particular value forms the other side.

[0046] As used herein, the terms “a / an” and “the / described” mean one or more species.

[0047] As used herein, the term “and / or” when used in a list of two or more items means that any one of the listed items may be used alone, or any combination of two or more of the listed items may be used. For example, if a composition is described as containing components A, B and / or C, the composition may contain: A alone; B alone; C alone; a combination of A and B; a combination of A and C; a combination of B and C; or a combination of A, B and C.

[0048] As used herein, the term “comprising / comprises / comprise” is an open transitional term used to transition from an object described before the term to one or more elements described after the term, wherein one or more elements listed after the transitional term are not necessarily the only elements constituting the object.

[0049] As used in this article, the term “having / has / have” has the same open-ended meaning as “includes” provided above.

[0050] As used in this article, the term "including (including / includes / include)" has the same open-ended meaning as "include" provided above.

[0051] As used in this article, “selected from” can be used with “or” or “and”. For example, “Y selected from A, B and C” means that Y can be A, B or C alone. Or, “Y selected from A, B or C” means that Y can be: A, B or C alone; or, a combination of A and B, a combination of A and C, a combination of B and C, or a combination of A, B and C.

[0052] As used herein, a numerical range is intended to include the starting value and the ending value within that range, as well as all values ​​and ranges between the starting and ending values. For example, a range of 40°C to 60°C includes a range of 40°C to 59°C, a range of 41°C to 60°C, a range of 41.5°C to 55.75°C, and ranges of 40°C, 41°C, 42°C, 43°C, etc., up to 60°C.

[0053] The inventors have unexpectedly discovered that coating compositions based on TMCD polyester and modified polyester polyols provide desired coating properties for metal packaging applications, such as a good balance of solvent resistance, acid resistance, distillation resistance, crack resistance, and flexural strength. Therefore, in one embodiment of the invention, a coating composition with improved coating properties for metal packaging applications is provided, comprising:

[0054] a. 2,2,4,4-Tetramethyl-1,3-cyclobutanediol (TMCD) polyester, which is a reaction product of a monomer, said monomer comprising:

[0055] i. Based on the total number of moles in (a)(i-iv), the amount of TMCD is 35 mol%-80 mol%.

[0056] ii. Based on the total moles of (a)(i-iv), 20 mol%–65 mol% of 1,4-cyclohexanediethanol (1,4-CHDM),

[0057] iii. Based on the total molar number of (a)(i-iv), the amount of diols that are different from TMCD and different from 1,4-CHDM, ranging from 0 mol% to 25 mol%.

[0058] iv. Based on the total moles of (a)(i-iv), 0 mol%-5 mol% of trimethylolpropane (TMP),

[0059] v. Based on the total number of moles of (a)(v-vi), 90 mol%-100 mol% of aromatic diacids.

[0060] vi. Based on the total number of moles of (a)(v-vi), aliphatic diacids in amounts ranging from 0 mol% to 10 mol%.

[0061] b. A modified polyester, which is a reaction product of a monomer, said monomer comprising:

[0062] i. Based on the total number of moles in (b)(i-iii), 30 mol%-55 mol% of cyclic diols,

[0063] ii. Based on the total moles of (b)(i-iii), 30 mol%-67 mol% of 2-methyl-1,3-propanediol (MP diol),

[0064] iii. Based on the total number of moles in (b)(i-iii), 3 mol%-20 mol% of trimethylolpropane (TMP),

[0065] iv. Based on the total molar amount of (b)(iv-v), 55 mol%-85 mol% of terephthalic acid (TPA) or isophthalic acid (IPA) or a mixture thereof,

[0066] v. Based on the total molar number of (b)(iv-v), the amount of aliphatic diacid is 15 mol%-45 mol%.

[0067] c. One or more crosslinking agents selected from the group consisting of: methyl phenolic resins, isocyanates, and amino resin crosslinking agents.

[0068] The TMCD polyester has a glass transition temperature (Tg) of 60 to 110°C, an acid value of 0 to 8 mg KOH / g, a hydroxyl value of 3 to 25 mg KOH / g, a number-average molecular weight (Mn) of 5,000 to 20,000 g / mol, and a weight-average molecular weight (Mw) of 10,000 to 100,000 g / mol; the modified polyester has a Tg of 20 to 50°C, an acid value of 0 to 10 mg KOH / g, a hydroxyl value of 30 to 60 mg KOH / g, a Mn of 2,000 to 10,000 g / mol, and a Mw of 10,000 to 150,000 g / mol; and the coating has a solvent resistance of greater than 70 MEK bi-friction as measured by ASTM D7835, and a wedge bending resistance (% qualified) of 60-100 as measured by ASTM D3281.

[0069] In another embodiment, the coating has a qualified crack resistance rating of 60-100% and a total dry distillation resistance rating (%), which is measured by the method specified in the Examples section.

[0070] In some embodiments of the present invention, the amount of TMCD(a)(i) is 35-80 mol%, 38-70 mol%, 40-65 mol%, 40-60 mol%, 40-55 mol%, 40-50 mol%, or 40-45 mol% based on the total number of moles of (a)(i-iv).

[0071] In some embodiments of the invention, the amount of 1,4-CHDM(a)(ii) is 20-65 mol%, 25-60 mol%, 30-55 mol%, 35-50 mol%, or 40-45 mol% based on the total number of moles of (a)(i-iv).

[0072] In some embodiments of the invention, the amount of the diol (a)(iii), which is different from TMCD and different from 1,4-CHDM, is 0-25 mol%, 0-20 mol%, 0-15 mol%, 0-10 mol%, or 0-5 mol%, based on the total number of moles of (a)(i-iv).

[0073] In some embodiments of the invention, the amount of TMP(a)(iv) is 0-5 mol%, 0-4 mol%, 0-3 mol%, 0-2 mol%, or 0-1 mol% based on the total number of moles of (a)(i-iv).

[0074] In some embodiments of the invention, the amount of the aromatic diacid (a)(v) is 90-100 mol%, 95-100 mol%, or 97-100 mol% based on the total number of moles of (a)(v-vi).

[0075] In some embodiments of the invention, the amount of aliphatic diacid (a)(vi) is 0-10 mol%, 0-5 mol%, or 0-3 mol% based on the total number of moles of (a)(v-vi).

[0076] In another embodiment, based on the total number of moles of (a)(i-iv), the amount of TMCD(a)(i) is 40-65 mol%, the amount of 1,4-CHDM(a)(ii) is 35-60 mol%, the amount of diol (a)(iii) which is different from TMCD and different from 1,4-CHDM is 0-15 mol%, the amount of TMP(a)(iv) is 0-2 mol%, and based on the total number of moles of (a)(v-vi), the amount of aromatic diacid (a)(v) is 97-100 mol%, and the amount of aliphatic diacid (a)(vi) is 0-3 mol%.

[0077] The diols (a) and (iii) that are different from TMCD and 1,4-CHDM include 1,6-hexanediol, 2-methyl-1,3-propanediol (MP diol), neopentyl glycol, 1,3-cyclohexanediol (1,3-CHDM), and mixtures thereof. Ideally, the diols that are different from TMCD and 1,4-CHDM are 1,6-hexanediol, MP diol, or mixtures thereof.

[0078] The aromatic diacids (a)(v) include IPA, TPA, dimethyl isophthalate, dimethyl terephthalate, and mixtures thereof. Ideally, the aromatic diacid is IPA, TPA, or a mixture thereof.

[0079] The aliphatic diacids (a) and (vi) include adipic acid, cyclohexanedicarboxylic acid, dimethyl cyclohexanedicarboxylate, and mixtures thereof. Ideally, the aliphatic diacid is adipic acid, 1,4-cyclohexanedicarboxylic acid, or a mixture thereof.

[0080] The glass transition temperature (Tg) of the TMCD polyester (a) is 60-110℃, 60-100℃, 60-95℃, 60-90℃, 65-100℃, 65-95℃, 65-90℃, 70-110℃, 70-100℃, 70-95℃, 70-90℃, 75-100℃, 75-95℃, 75-90℃, 80-100℃, 80-95℃, or 80-90℃.

[0081] The number-average molecular weight (Mn) of the TMCD polyester (a) is 5,000-20,000, 6,000-15,000, or 7,000-13,000 g / mol; and the weight-average molecular weight (Mw) is 10,000-100,000, 20,000-90,000, or 30,000-80,000 g / mol.

[0082] The acid value of the TMCD polyester (a) is 0-8, 0-5, 0-3, 0-2, 0-1, 1-5, 1-4, 1-3, 1-2, 2-5, 2-4, 2-3, 3-5 or 3-4 mgKOH / g.

[0083] The hydroxyl value of the TMCD polyester (a) is 3-25, 5-25, 10-25 or 10-22 mgKOH / g.

[0084] In some embodiments of the invention, the cyclic diol (b)(i) is present in an amount of 30-55 mol%, 35-50 mol%, or 40-45 mol%, based on the total number of moles of (b)(i-iii).

[0085] In some embodiments of the invention, the MP diol (b)(ii) is present in an amount of 30-67 mol%, 35-60 mol%, or 40-55 mol%, based on the total number of moles of (b)(i)-(iii).

[0086] In some embodiments of the invention, the TMP(b)(iii) is present in an amount of 3-20 mol%, 4-15 mol%, or 5-12 mol%, based on the total number of moles of (b)(i)-(iii).

[0087] In some embodiments of the invention, the TPA and / or IPA(b)(iv) are present in amounts of 55-85 mol%, 60-80 mol%, or 65-75 mol%, based on the total number of moles of (b)(iv)-(v).

[0088] In some embodiments of the invention, the aliphatic diacid (b)(v) is present in an amount of 15-45 mol%, 20-40 mol%, or 25-35 mol%, based on the total number of moles of (b)(iv)-(v).

[0089] In another embodiment of the invention, the cyclic diol (b)(i) is present in an amount of 40-45 mol% based on the total molar number of (b)(i)-(iii); the MP diol (b)(ii) is present in an amount of 40-55 mol% based on the total molar number of (b)(i)-(iii); the TMP (b)(iii) is present in an amount of 5-12 mol% based on the total molar number of (b)(iv)-(v); the TPA and / or IPA (b)(iv) is present in an amount of 65-75 mol% based on the total molar number of (b)(iv)-(v); and the aliphatic diacid (b)(v) is present in an amount of 25-35 mol% based on the total molar number of (b)(iv)-(v).

[0090] The cyclic diols (b)(i) include tricyclic sebacic acid diethanol (TCDDM), TMCD, isosorbide, 1,4-CHDM, 1,3-CHDM, and mixtures thereof. Ideally, the cyclic diol is TCDDM, TMCD, or a mixture thereof.

[0091] The TCDDM (Formula 1) is 4,8-bis(hydroxymethyl)tricyclic [5.2.1.0] 2,6 A mixture of decane isomers. TCDDM is also known as tricyclic decanediethanol and tricyclic [5.2.1.0] 2,6 Decane-4,8-diethanol. TCDDM is available from OQ Chemicals as TCD AlcoholDM.

[0092]

[0093] The TPA includes terephthalic acid and its esters, such as dimethyl terephthalate.

[0094] The IPA includes isophthalic acid and its esters, such as dimethyl isophthalate.

[0095] The aliphatic diacid(b)(v) includes C4-C 12 Dicarboxylic acids and their esters, such as succinic acid, adipic acid, sebacic acid, dodecanoic acid, cyclohexanedicarboxylic acid and its methyl esters; and (hydrogenated) dimer acids (C 36 Ideally, when using long-chain diacids (>C), 10 When these are present, their proportions are relatively small, for example, 15 mol%-25 mol%, 15 mol%-20 mol%, or 15 mol%-17 mol%. In one aspect, the aliphatic diacid is sebacic acid, adipic acid, or a mixture thereof in a proportion of 25 mol%-35 mol%.

[0096] The glass transition temperature (Tg) of the modified polyester is 20-50℃, 20-45℃, 20-40℃, 23-38℃, or 25-35℃.

[0097] The modified polyester has a number-average molecular weight of 2,000-10,000, 3,000-9,000, or 4,000-8,000 g / mol; and a weight-average molecular weight of 10,000-150,000, 15,000-130,000, or 20,000-100,000 g / mol.

[0098] The modified polyester has an acid value of 0-10, 0-8, 0-5, 0-3, 0-2 or 0-1 mgKOH / g.

[0099] The modified polyester has a hydroxyl value of 30-60, 35-55, or 40-50 mgKOH / g.

[0100] In another embodiment of the invention, based on the total weight of (a) and (b), the amount of TMCD polyester (a) is 40-95 wt%, 45-90 wt%, 45-85 wt%, 45-80 wt%, 45-75 wt%, 45-70 wt%, 45-65 wt%, 45-60 wt%, 45-55 wt%, 50-90 wt%, 50-85 wt%, 50-80 wt%, 50-75 wt%, 50-70 wt%, 50-65 wt%, 50- 60wt%, 55-90wt%, 55-85wt%, 55-80wt%, 55-75wt%, 55-70wt%, 55-65wt%, 60-90wt%, 60-85wt%, 60-80wt%, 60 -75wt%, 60-70wt%, 65-90wt%, 65-85wt%, 65-80wt%, 65-75wt%, 70-90wt%, 70-85wt%, 70-80wt%, 75-90wt%, 7 5-85 or 80-90 wt%, the amount of modified polyester (b) is 5-60 wt%, 10-55 wt%, 15-55 wt%, 20-55 wt%, 25-55 wt%, 30-55 wt%, 35-55 wt%, 40-55 wt%, 45-55 wt%, 10-50 wt%, 15-50 wt%, 20-50 wt%, 25-50 wt%, 30-50 wt%, 35-50 wt%, 40-50 wt%, 10-45 wt%, 15 -45wt%, 20-45wt%, 25-45wt%, 30-45wt%, 35-45wt%, 10-40wt%, 15-40wt%, 20-40wt%, 25-40wt%, 30-40wt%, 10-35wt%, 15-35wt%, 20-35wt%, 25-35wt%, 10-30wt%, 15-30wt%, 20-30wt%, 10-25wt%, 15-25wt%, or 10-20wt%. Ideally, based on the total weight of (a) and (b), the amount of TMCD polyester (a) is 45-65wt%, and the amount of modified polyester (b) is 35-55wt%.

[0101] The crosslinking agent (c) is selected from one or more of the group consisting of: methyl phenolic resins, isocyanates, and amino resin crosslinking agents. Ideally, the crosslinking agent is a methyl phenolic resin, an isocyanate, or a mixture thereof.

[0102] The methyl phenolic resin contains residues of unsubstituted phenols and / or meta-substituted phenols. These specific methyl phenolic resins exhibit good reactivity with the polyester polyol (a). Ideally, the amount of methyl phenolic resin is at least 50 wt%, or greater than 60 wt%, or greater than 70 wt%, or greater than 80 wt%, or greater than 90 wt%, based on the weight of all crosslinking agent compounds.

[0103] The methyl phenolic resin present in the crosslinking composition contains a hydroxymethyl group on the phenolic ring. Phenolic resins with hydroxymethyl functionality are referred to as methyl phenolic resins. As is known in the art, the hydroxymethyl group (--CH2OH) can be etherified with an alcohol and present as --CH2OR, where R is a C1-C8 alkyl group, to improve resin properties such as storage stability and compatibility. For descriptive purposes, the term "hydroxymethyl" as used herein includes both --CH2OH and --CH2OR, and the unsubstituted hydroxymethyl group is CH2OH. The hydroxymethyl group (--CH2OH or --CH2OR) is an end group attached to the methyl phenolic resin. The hydroxymethyl group is formed during the synthesis of the methyl phenolic resin and can further react with another molecule to form an ether or methylene bond, thereby forming a macromolecule.

[0104] Phenolic resins contain residues of unsubstituted or meta-substituted phenols. When preparing methyl phenolic resins from phenols or meta-substituted phenols, both para and ortho positions can be used for bridging reactions to form a branched network, wherein the final hydroxymethyl terminal group on the resin is in the para or ortho position relative to the phenolic hydroxyl group. To prepare methyl phenolic resins, a phenolic composition is used as the starting material. The phenolic composition contains unsubstituted and / or meta-substituted phenols. Based on the weight of the phenolic composition used as the starting material, the amount of unsubstituted, meta-substituted, or a combination of both present in the phenolic composition used as a reactant to prepare the methyl phenolic resin is at least 50 wt%, or at least 60 wt%, or at least 70 wt%, or at least 75 wt%, or at least 80 wt%, or at least 85 wt%, or at least 90 wt%, or at least 95 wt%, or at least 98 wt%.

[0105] The phenolic composition is reacted with a reactive compound, such as an aldehyde, in the following aldehyde:phenol molar ratio (using aldehyde as an example): greater than 1:1, or at least 1.05:1, or at least 1.1:1, or at least 1.2:1, or at least 1.25:1, or at least 1.3:1, or at least 1.35:1, or at least 1.4:1, or at least 1.45:1, or at least 1.5:1, or at least 1.55:1, or at least 1.6:1, or at least 1.65:1, or at least 1.7:1, or at least 1.75:1, or at least 1.8:1, or at least 1.85:1, or at least 1.9:1, or at least 1.95:1, or at least 2:1. There is no upper limit to the amount of aldehyde, which can be up to 30:1, but typically at most 5:1, or at most 4:1, or at most 3:1, or at most 2.5:1. Typically, the aldehyde:phenol ratio is at least 1.2:1 or greater, or 1.4:1 or greater, or 1.5:1 or greater, and usually at most 3:1. Ideally, these ratios also apply to the ratio of aldehyde to unsubstituted phenol or meta-substituted phenol.

[0106] Each phenolic hydroxyl group in a methyl phenolic resin may contain an average of at least 0.3, or at least 0.4, or at least 0.45, or at least 0.5, or at least 0.6, or at least 0.8, or at least 0.9 hydroxymethyl groups, and "hydroxymethyl" includes both --CH2OH and --CH2OR.

[0107] Phenolic resins are obtained by the condensation of phenol with an aldehyde of the general formula (RCHO)n, where R is hydrogen or a hydrocarbon group having 1-8 carbon atoms, and n is 1, 2, or 3. Examples include formaldehyde, metaldehyde, acetaldehyde, glyoxal, propionaldehyde, furfural, or benzaldehyde. Ideally, phenolic resins are the reaction products of phenol and formaldehyde.

[0108] (c) At least a portion of the crosslinking agent comprises a methyl phenolic resin, which is prepared by reacting an unsubstituted phenol or a meta-substituted phenol, or a combination thereof, with an aldehyde. The unsubstituted phenol is phenol (C6H5OH). Examples of meta-substituted phenols include m-cresol, m-ethylphenol, m-propylphenol, m-butylphenol, m-octylphenol, m-alkylphenol, m-phenylphenol, m-alkoxyphenol, 3,5-xylenol, 3,5-diethylphenol, 3,5-dibutylphenol, 3,5-dialkylphenol, 3,5-dicyclohexylphenol, 3,5-dimethoxyphenol, 3-alkyl-5-alkoxyphenol, etc.

[0109] Although other substituted phenolic compounds may be used in combination with the unsubstituted or meta-substituted phenols to prepare phenolic resins, it is desirable that at least 50%, or at least 70%, or at least 80%, or at least 90%, or at least 95%, or at least 98%, or at least 100% of the phenolic compounds used to prepare methyl phenolic resins are unsubstituted or meta-substituted phenols.

[0110] In one aspect, the methyl phenolic resin used in this invention contains meta-substituted phenolic residues.

[0111] Examples of suitable commercial phenolic resins include, but are not limited to, those available from Allenx. PR516 / 60B (based on cresol and formaldehyde), also available from Allenx PR 371 / 70B (based on unsubstituted phenol and formaldehyde) and CURAPHEN 40-856B60 (based on m-cresol and formaldehyde), which is available from Bitrez.

[0112] Phenolic resins are ideally thermosetting. Ideally, phenolic resins are not prepared by adding bisphenol A, F, or S (collectively referred to as "BPA").

[0113] Ideally, methyl phenolic resins are alcohol-soluble. They can be liquid at 25°C. The weight-average molecular weight of methyl phenolic resins can range from 200 to 2000, typically 300 to 1000, 400 to 800, or 500 to 600.

[0114] The isocyanate crosslinking agent suitable for use in this invention can be a capped or uncapped isocyanate type. Examples of suitable isocyanate crosslinking agents include, but are not limited to, 1,6-hexamethylene diisocyanate, methylene bis(4-cyclohexyl isocyanate), and isophorone diisocyanate. Ideally, the isocyanate crosslinking agent is isophorone diisocyanate (IPDI) or capped IPDI, which can be obtained from COVESTRO. Obtained in BL 2078 / 2.

[0115] In another embodiment, the crosslinking agent (c) is a mixture of 70wt%-90wt% of a methyl phenolic resin and 10wt%-30wt% of an isocyanate based on the total weight of the crosslinking agent.

[0116] In another embodiment of the invention, based on the total weight of (a), (b) and (c), the total amount of TMCD polyester (a) and modified polyester (b) is 50-90 wt%, and the amount of crosslinking agent (c) is 10-50 wt%.

[0117] In some embodiments, the total amount of TMCD polyester (a) and modified polyester (b) is 55-85 wt%, 55-80 wt%, 55-75 wt%, 55-70 wt%, 60-85 wt%, 60-80 wt%, 60-75 wt%, 60-70 wt%, 65-85 wt%, 65-80 wt%, 65-75 wt%, 70-90 wt%, 70-85 wt%, 70-80 wt%, 75-85 wt%, 80-90 wt%. Or 80-85 wt%; and crosslinking agent (c) is 15-45 wt%, 20-45 wt%, 25-45 wt%, 30-45 wt%, 15-40 wt%, 20-40 wt%, 25-40 wt%, 30-40 wt%, 15-35 wt%, 20-35 wt%, 25-35 wt%, 10-30 wt%, 15-30 wt%, 20-30 wt%, 15-25 wt%, 10-20 wt%, or 15-20 wt%.

[0118] In addition to methyl phenolic resins and isocyanates, the crosslinking agent (c) can also be an amino resin. The amino resin crosslinking agent (or crosslinking agent) can be a melamine-formaldehyde type or a benzoguanamine-formaldehyde type crosslinking agent, i.e., having multiple -N(CH2OR) crosslinking agents. 3 Crosslinking agents with 2 functional groups, wherein R 3 It is a C1-C4 alkyl group, preferably methyl.

[0119] In yet another embodiment, the crosslinking agent (c) is a mixture of 65 wt% to 85 wt% of an amino resin and 15 wt% to 35 wt% of an isocyanate based on the total weight of the crosslinking agent.

[0120] Typically, the amino crosslinking agent can be selected from compounds of the following formula, where R 3 Independently C1-C4 alkyl:

[0121]

[0122] Amino-containing crosslinking agents are ideally hexamethoxymethyl melamine, hexabutoxymethyl melamine, tetramethoxymethyl benzoguanamine, tetrabutoxymethyl benzoguanamine, tetramethoxymethylurea, and mixed butoxy / methoxy substituted melamines.

[0123] Ideally, in all types of thermosetting compositions, the crosslinking agent composition contains greater than 50 wt%, or greater than 60 wt%, or greater than 70 wt%, or greater than 80 wt%, or greater than 90 wt% of a methyl phenolic resin, based on the weight of the crosslinking agent composition. Alternatively, the remaining crosslinking compounds in the crosslinking composition (if any) are amine-based crosslinking compounds and / or isocyanate crosslinking agents as described above.

[0124] Any thermosetting composition of the present invention may further comprise one or more crosslinking catalysts. Representative crosslinking catalysts include carboxylic acids, sulfonic acids, tertiary amines, tertiary phosphines, tin compounds, or combinations thereof. Some specific examples of crosslinking catalysts include p-toluenesulfonic acid, phosphoric acid, and NACURE, sold by King Industries. TM Catalysts 155, 5076, 1051 and XC-296B, BYK 450, 470, methyltoluenesulfonylimide, p-toluenesulfonic acid, dodecylbenzenesulfonic acid, dinonylnaphthalenesulfonic acid and dinonylnaphthalenedisulfonic acid, benzoic acid, triphenylphosphine, dibutyltin dilaurate and dibutyltin diacetate, are available from BYK-Chemie USA.

[0125] The crosslinking catalyst may vary depending on the type of crosslinking agent used in the coating composition. For example, the crosslinking agent may include melamine or “amino” crosslinking agents, and the crosslinking catalyst may include p-toluenesulfonic acid, phosphoric acid, uncapped and capped dodecylbenzenesulfonic acid (hereinafter abbreviated as “DDBSA”), dinonylnaphthalenesulfonic acid (hereinafter abbreviated as “DNNSA”), and dinonylnaphthalenedisulfonic acid (hereinafter abbreviated as “DNNDSA”). Some of these catalysts are commercially available, such as NACURE. TM 155, 5076, 1051, 5225 and XC-296B (available from King Industries), BYK-CATALYSTS TM (Available from BYK Chemie USA) and CYCAT TM Catalyst (available from Cytec Surface Specialties). The coating compositions of the present invention may contain one or more isocyanate crosslinking catalysts, such as FASCAT. TM 4202 (Dibutyltin dilaurate), FASCAT TM 4200 (dibutyltin diacetate, both available from Arkema), DABCO TM T-12 (available from Air Products) and K-KAT TM 348, 4205, 5218, XC-6212 TM Non-tin catalysts (available from King Industries) and tertiary amines.

[0126] Based on the total weight of any of the above-described curable polyester resin and crosslinking agent compositions, the coating composition may contain an amount of acid or base catalyst ranging from 0.1 wt% to 2 wt%.

[0127] In another embodiment, the coating composition of the present invention further comprises one or more organic solvents. Suitable organic solvents include xylene, ketones (e.g., methylpentyl ketone), 2-butoxyethanol, ethyl 3-ethoxypropionate, toluene, butanol, cyclopentanone, cyclohexanone, ethyl acetate, butyl acetate, Aromatic 100, and Aromatic 150 (both available from ExxonMobil) and other volatile inert solvents commonly used in industrial baking (i.e., thermosetting) enamels, mineral oil, naphtha, toluene, acetone, methyl ethyl ketone, methyl isopentyl ketone, isobutyl acetate, tert-butyl acetate, n-propyl acetate, isopropyl acetate, methyl acetate, ethanol, n-propanol, isopropanol, sec-butanol, isobutanol, ethylene glycol monobutyl ether, propylene glycol n-butyl ether, propylene glycol methyl ether, propylene glycol monopropyl ether, dipropylene glycol methyl ether, diethylene glycol monobutyl ether, trimethylpentanediol monoisobutyrate, ethylene glycol monooctyl ether, diacetone alcohol, 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate (available from Eastman Chemical Company under the trademark TEXANOL) TM (obtained through commercial purchase), or a combination thereof.

[0128] Based on the weight of the solvent-containing coating composition, the amount of solvent is ideally at least 20 wt%, or at least 25 wt%, or at least 30 wt%, or at least 35 wt%, or at least 40 wt%, or at least 45 wt%, or at least 50 wt%, or at least 55 wt%. Additionally, or alternatively, the amount of organic solvent may be up to 85 wt% based on the weight of the coating composition.

[0129] In some embodiments of the invention, the coating has a MEK bifriction rating of 70 to 100 or greater, 80 to 100 or greater, or 90 to 100 or greater, as measured by ASTM D7835; and a wedge bending resistance (% qualified) of 60-100, 65-100, 70-100, 75-100, or 80-100 as measured by ASTM D3281. In further embodiments of the invention, the coating has a qualified crack resistance rating and a total distillation resistance rating (%) of 60-100, 70-100, 80-100, or 90-100, as measured by the methods specified in the Examples section.

[0130] In another embodiment, the present invention provides a coating composition for gold coating with improved coating properties for metal packaging applications, comprising:

[0131] a. Based on the total weight of (a), (b), (c), and (d), 30-40 wt% of a 2,2,4,4-tetramethyl-1,3-cyclobutanediol (TMCD) polyester, which is the reaction product of a monomer comprising:

[0132] i. Based on the total number of moles in (a)(i-iv), the amount of TMCD is 35 mol%-80 mol%.

[0133] ii. Based on the total moles of (a)(i-iv), 20 mol%–65 mol% of 1,4-cyclohexanediethanol (1,4-CHDM),

[0134] iii. Based on the total molar number of (a)(i-iv), the amount of diols that are different from TMCD and different from 1,4-CHDM, ranging from 0 mol% to 25 mol%.

[0135] iv. Based on the total moles of (a)(i-iv), 0 mol%-5 mol% of trimethylolpropane (TMP),

[0136] v. Based on the total number of moles of (a)(v-vi), 90 mol%-100 mol% of aromatic diacids.

[0137] vi. Based on the total number of moles of (a)(v-vi), aliphatic diacids in amounts of 0 mol% to 10 mol%.

[0138] b. Based on the total weight of (a), (b), (c), and (d), 30-40 wt% of a modified polyester, which is a reaction product of a monomer comprising:

[0139] i. Based on the total molar number of (b)(i-iii), 30 mol%-55 mol% of cyclic diols,

[0140] ii. Based on the total moles of (b)(i-iii), 30 mol%-67 mol% of 2-methyl-1,3-propanediol (MP diol),

[0141] iii. Based on the total number of moles in (b)(i-iii), 3 mol%-20 mol% of trimethylolpropane (TMP),

[0142] iv. The total molar amount of base (b)(iv-v), 55 mol%-85 mol% of terephthalic acid (TPA) or isophthalic acid (IPA) or a mixture thereof,

[0143] v. Based on the total molar number of (b)(iv-v), the amount of aliphatic diacid is 15 mol%-45 mol%.

[0144] c. Based on the total weight of (a), (b), and (c), 15-30 wt% of methyl phenolic resin, and

[0145] d. Based on the total weight of (a), (b), and (c), 5-15 wt% of isophorone diisocyanate (IPDI),

[0146] The TMCD polyester has a glass transition temperature (Tg) of 60 to 110°C, an acid value of 0 to 8 mg KOH / g, a hydroxyl value of 3 to 25 mg KOH / g, a number-average molecular weight (Mn) of 5,000 to 20,000 g / mol, and a weight-average molecular weight (Mw) of 10,000 to 100,000 g / mol; the modified polyester has a Tg of 20 to 50°C, an acid value of 0 to 10 mg KOH / g, a hydroxyl value of 30 to 60 mg KOH / g, a Mn of 2,000 to 10,000 g / mol, and a Mw of 10,000 to 150,000 g / mol; and the coating has a solvent resistance of greater than 70 MEK bi-friction as measured by ASTM D7835, and a wedge bending resistance (% qualified) of 60-100 as measured by ASTM D3281.

[0147] In another embodiment, the coating has a qualified crack resistance rating and a total dry distillation resistance rating of 60-100% (qualified), measured by the method specified in the Examples section.

[0148] The coating composition may also contain at least one pigment. Typically, the pigment is present in an amount of about 20 wt% to about 60 wt% based on the total weight of the composition. Examples of suitable pigments include titanium dioxide, barite, clay, calcium carbonate, and CI Pigment White 6 (titanium dioxide). For example, solvent-based coating formulations may contain titanium dioxide as a white pigment, which can be obtained from CHEMOURS using Ti-Pure... TM R900 obtained.

[0149] After formulation, the coating composition can be applied to a substrate or article. Therefore, another aspect of the invention is a molded or shaped article coated with the coating composition of the invention. The substrate can be any common substrate, such as aluminum, tin, steel, or galvanized sheet; polyurethane elastomer; a primer-coated (painted) substrate, etc. The coating composition can be applied to the substrate using techniques known in the art, for example by spraying, scraping, rolling, etc., applying a wet coating of about 0.1 to about 4 mils (1 mil = 25 μm), or 0.5 to 3, or 0.5 to 2, or 0.5 to 1 mil to the substrate. The coating can be cured at a temperature of about 50°C to about 230°C for about 5 seconds to about 90 minutes and then cooled. Examples of coated articles include metal cans for food and beverages, wherein the interior is coated with the coating composition of the invention.

[0150] Therefore, the present invention also provides an article of which at least a portion is coated with the coating composition of the present invention.

[0151] Example

[0152] The present invention can be further illustrated by the following examples, but it should be understood that, unless otherwise expressly stated, these examples are included for illustrative purposes only and are not intended to limit the scope of the invention.

[0153] abbreviation:

[0154] mL is milliliters; wt% is weight percentage; eq is equivalent; hrs or h is hours; mm is millimeters; m is meters; ℃ is degrees Celsius; min is minutes; g is grams; mmol is millimoles; mol is moles; kg is kilograms; L is liters; w / v is weight / volume; μL is microliters; MW is molecular weight.

[0155] Coating testing methods:

[0156] Substrate, preparation of coated test plates, film weight

[0157] The electroplated tinplate (ETP) substrate was supplied by two vendors: Lakeside Metals Inc. – 0.23mm thick, 2.2g / m³. 2 Tin content, tempering and annealing type are T61CA, and it is manufactured by Reynolds Metals Company—0.19mm thickness, 2.2g / m². 2 The tin content, tempering, and annealing type are DR-8CA. The substrate is coated with a wet film by casting using a wire-wound bar, with RDS14 used for coloring and RDS 10 for gold (RDS 14 and RDS 10 are available from RD Specialties, Inc.). This produces a final dry film weight of approximately 14-16 g / m² for the color coating. 2 For gold paint, it is approximately 6-8 grams per cubic meter. 2 The cast plate was placed vertically in a holder and held in an oven for curing. The Despatch forced air oven was preheated to 203°C. The coated plate was then placed in the oven for an 18-minute baking cycle to allow the coating to bake at a peak metallographic temperature (PMT) of 200°C for 10 minutes. At the end of the baking cycle, the plate holder was removed from the oven and allowed to cool back to ambient conditions. The dry film weight of the applied coating was determined using a Sencon SI9600 coating thickness gauge.

[0158] wedge bend

[0159] Cut a 1.5-inch wide x 4-inch long specimen from the coated plate. Test the specimen using a Gardco combined bending and impact testing machine according to ASTM D 3281. For the bending test, first bend the coated specimen on a 1 / 8-inch (0.32 cm) steel strip. Place the bent specimen between the butt hinge sections. The hinge, made of two steel blocks, is attached to a base below the conduit. When the hinge is closed, it creates a wedge-shaped gap between the upper and lower sections, ranging from 1 / 8 inch at the hinged end to zero thickness at the free end. Then, drop a flat-down impact tool from a height of one or two feet onto the upper part of the hinge. Once the coated specimen is bent and impacted into a wedge shape, immerse it in an acidified copper sulfate solution (5 wt% copper sulfate, 15 wt% hydrochloric acid (35%), 80 wt% distilled water) for 5 minutes to make any coating cracks visible. Remove excess copper sulfate solution by washing with water and patting dry with a towel. Wedge bending failure (mm), measured using a ruler and a luminous magnifying glass, is defined as the total length of a continuous crack along the bending edge of the specimen. The result is reported as the acceptable percentage of wedge bending, which is calculated as follows:

[0160]

[0161] In this experiment, each qualified percentage of the wedge bending was the average of three replicates.

[0162] Methyl ethyl ketone (MEK) double friction

[0163] Resistance to MEK solvents was measured using a MEK friction tester (Gardco MEK Friction Tester AB-410103EN with a 1 kg block). The test was performed according to a method similar to ASTM D7835. MEK solvent resistance was reported as the number of double friction cycles the coated board could withstand before the coating began to be removed. For example, one round trip constitutes one double friction cycle. The upper limit for each evaluation was set at a maximum of 100 double friction cycles.

[0164] Sterilization resistance test

[0165] A 2.5-inch wide x 4-inch long coated sample was cut from the coated plate. The sample was then placed in a 16-ounce wide-mouthed Le Parfait glass jar, half of which contained food simulants, with one half of the sample above the food simulant liquid and the other half immersed in it. Two different food simulants were evaluated:

[0166] • Lactic acid: 2% lactic acid, 98% deionized water.

[0167] Acetic acid: 3% acetic acid, 97% deionized water.

[0168] Place the appropriately sealed container in an autoclave (Priorcave Model PNA / QCS / EH150) and incubate at 131°C for 1 hour. Once the pyrolysis process is complete, reduce the pressure in the autoclave to ambient conditions. After the sterilization cycle is complete, remove the glass container containing the sample from the autoclave. Remove the sample from the container, wash with water, and blot dry with paper towels. Pyrolysis performance is typically rated on a scale of 0 (worst) to 5 (best) using visual inspection. For each food simulant, pyrolysis performance is rated according to (1) redness in the gas phase, (2) redness in the liquid phase, (3) roughness in the gas phase, (4) roughness in the liquid phase, and (5) cross-cut adhesion in the liquid phase (according to ASTM D 3359). The total pyrolysis performance is reported as a percentage of total pyrolysis, calculated as follows:

[0169]

[0170] Each distillation grade in this experiment is the average grade from two repeated experiments.

[0171] Cracking test grade

[0172] Cut a 1.0-inch wide × 4.0-inch long coated specimen from the coated plate. To prepare the specimen for the cracking test, uniformly bend the coated specimen with the coated side facing outwards onto a 12 mm diameter steel rod for 1–2 seconds at a bending angle of 180 degrees. This bending test is performed similarly to the cylindrical mandrel bending test (ASTM D522). In the test, the bending is transverse to the grain direction of the substrate and the tensile direction of the coating (the grain direction of the substrate is parallel to the tensile direction of the coating). After the bending test, the specimen is placed under constant temperature and humidity conditions (22.8 °C ± 2; 50 % RH ± 5) for 24 hours, and then the cracking is evaluated.

[0173] When assessing crack grading, a flashlight is shone on the curved area to whiten and make any coating cracks or microcracks visible. Any whitening or cracks observed in the curved area are considered a "failure" in crack grading. Otherwise, it is considered "acceptable". In this experiment, the final "acceptable" grade of the sample is the result of two repeated, consistent "acceptable" grades. Otherwise, the final rating of the sample is considered a "failure".

[0174] Example 1: Synthesis of modified polyester polyol-modified resin 1 (MR1)

[0175] Polyols were produced using a resin-filled reactor setup controlled by automated control software. Compositions were prepared in 3.5 mol scale using a 2L vessel with a top stirrer and a partial condenser with a top-mounted main condenser and a Dean Stark separator. Approximately 10 wt% (based on reaction yield) of high-boiling azeotropic solvents (A150 and A150ND) was used to facilitate the removal of water condensate from the reaction mixture, and a standard paddle stirrer was used to maintain the reaction mixture at a reasonable viscosity. Isophthalic acid (IPA), adipic acid (AD), 2,2,4,4-tetramethyl-1,3-cyclobutanediol (TMCD), 2-methyl-1,3-propanediol (MPdiol), and Aromatic 150 were added to the reactor, which was then fully assembled. After assembling the reactor and covering it with nitrogen, Fascat 4100 (monobutyltin oxide) was added through a sampling port. Additional A150 / A150ND solvent was added to the Dean Stark separator to maintain a solvent level of approximately 10 wt% in the reactor. Using the set output controlled by an automated system, the reaction mixture was heated from room temperature to 150°C without stirring. Once the reaction mixture was sufficiently fluid, stirring was initiated to promote uniform heating of the mixture. At 150°C, the heating control was switched to automatic control, and the temperature was increased to 230°C over a 4-hour period. The reaction was maintained at 230°C and sampled every 1–2 hours after clarification until the desired acid value was reached (approximately 4 hours). The reaction mixture was then further diluted with A150ND to a target of 55% by weight of solids. The solution was filtered through an approximately 250 μm paint filter before use for formulation and application testing. It should be noted that the glycol excess was determined based on experience with laboratory reactors and may vary depending on the partial condenser and reactor design used. The glycol:acid ratio was also controlled to achieve the same molecular weight with simple variations in acid and hydroxyl end-group content.

[0176]

[0177] Example 2: Modified polyester polyol-modified resin 2 (MR) 2) Synthesis

[0178] Polyols were produced using a resin-refined reactor setup controlled by automated control software. The composition was prepared using a 2L vessel with a top stirrer and a partial condenser with a top-mounted main condenser and a Dean Stark separator. Approximately 10 wt% (based on reaction yield) of a high-boiling azeotropic solvent (A150ND) was used to facilitate the removal of water condensate from the reaction mixture, and a standard paddle stirrer was used to maintain the reaction mixture at a reasonable viscosity. Isophthalic acid (IPA), adipic acid (AD), 2,2,4,4-tetramethyl-1,3-cyclobutanediol (TMCD), 2-methyl-1,3-propanediol (MP-diol), trimethylolpropane (TMP), and Aromatic 150ND were added to the reactor, which was then fully assembled. After assembling the reactor and covering it with nitrogen, Fascat 4100 (monobutyltin oxide) catalyst was added through a sampling port. Additional A150ND solvent was added to the Dean Stark separator to maintain a solvent level of approximately 10 wt% in the reactor. Using the set output controlled by an automated system, the reaction mixture was heated from room temperature to 150°C without stirring. Once the reaction mixture was sufficiently fluid, stirring was initiated to promote uniform heating of the mixture. At 150°C, heating control was switched to automatic control, and the temperature was increased to 230°C over a 4-hour period. The reaction was maintained at 230°C and sampled every 1–2 hours after clarification until the desired acid value was reached. The reaction mixture was then further diluted with A150ND to a target of 55% by weight of solids. The solution was then filtered through an approximately 250 μm paint filter before use for formulation and application testing. It should be noted that the diol excess was determined based on experience with laboratory reactors and may vary depending on the partial condenser and reactor design used.

[0179]

[0180]

[0181] Example 3: Synthesis of modified polyester polyol-modified resin 3 (MR3)

[0182] Polyols were produced using a resin-refined reactor setup controlled by automated control software. The composition was prepared using a 2L vessel with a top stirrer and a partial condenser with a top-mounted main condenser and a Dean Stark separator. Approximately 10 wt% (based on reaction yield) of a high-boiling azeotropic solvent (A150ND) was used to facilitate the removal of water condensate from the reaction mixture, and a standard paddle stirrer was used to maintain the reaction mixture at a reasonable viscosity. Isophthalic acid (IPA), sebacic acid (SA), 2,2,4,4-tetramethyl-1,3-cyclobutanediol (TMCD), 2-methyl-1,3-propanediol (MP-diol), trimethylolpropane (TMP), and Aromatic 150ND were added to the reactor, which was then fully assembled. After assembling the reactor and covering it with nitrogen, Fascat 4100 (monobutyltin oxide) catalyst was added through a sampling port. Additional A150ND solvent was added to the Dean Stark separator to maintain a solvent level of approximately 10 wt% in the reactor. Using the set output controlled by an automated system, the reaction mixture was heated from room temperature to 150°C without stirring. Once the reaction mixture was sufficiently fluid, stirring was initiated to promote uniform heating of the mixture. At 150°C, heating control was switched to automatic control, and the temperature was increased to 230°C over a 4-hour period. The reaction was maintained at 230°C and sampled every 1–2 hours after clarification until the desired acid value was reached. The reaction mixture was then further diluted with A150ND to a target of 55% by weight of solids. The solution was then filtered through an approximately 250 μm paint filter before use for formulation and application testing. It should be noted that the diol excess was determined based on experience with laboratory reactors and may vary depending on the partial condenser and reactor design used.

[0183]

[0184]

[0185] Example 3: Composition and properties of synthesized modified polyester polyols

[0186] Table 1 lists the composition of resins 1-2, and Table 2 lists their resin properties.

[0187] Glass transition temperature (Tg) was determined using a Q2000 differential scanning calorimeter (DSC) from TA Instruments in Newcastle, Delaware, USA, at a scan rate of 20 °C / min. Number-average molecular weight (Mn) and weight-average molecular weight (Mw) were determined by gel permeation chromatography (GPC) using polystyrene equivalent molecular weight. Acid value was measured using a procedure based on ASTM D7253-1 entitled "Standard Test Method for Polyurethane Raw Materials: Determination of Acidity of Polyether Polyols," and hydroxyl value was measured using a procedure based on ASTM E222-1 entitled "Standard Test Method for Hydroxyl Groups Using Acetic Anhydride."

[0188] Table 1. Synthesized modified polyester polyols

[0189]

[0190] Table 2. Resin properties of modified polyester polyols

[0191] MR1 26 6600 20617 3.6 45 MR2 35 4400 37070 4.0 43 MR3 24 7860 71869 4.4 40

[0192] Example 4: Synthesis of TMCD Polyester (Resin 1)

[0193] TMCD polyesters having the compositions listed in Table 3 were prepared using the same method as described in Example 1. Table 4 lists their resin properties.

[0194] Table 3. Synthesized TMCD polyester

[0195]

[0196] Table 4. Resin properties of TMCD polyester

[0197] Resin 1 92 10500 42000 4 17

[0198] Example 4: Preparation of Gold Paint Formulation (GF) 1-3 and CGF 1)

[0199] Coating formulations for gold were prepared using each modified resin (MR 1-3) and TMCD polyester (resin 1). The gold formulations (GF 1-3) prepared from each modified resin and TMCD polyester are listed in Table 5. Table 5 also lists a comparative gold formulation (CGF 1) prepared using TMCD polyester (resin 1) without the modified resin. Table 6 lists the coating properties of the stated formulations.

[0200] Prior to formulation, all polyester polyols were diluted to 50 wt% solids in A150ND. Solvent blends were prepared from a mixture of xylene, butanol, and MAK at 30 wt%, 30 wt%, and 40 wt%, respectively. Empty, lidded glass jars were labeled and pre-weighed to record the tare weight. For each formulation, Curaphen 40-856-B60 was weighed separately. BL2078 / 2 XC-296B and solvent blends were added sequentially to the resin solution. Then, in Dispermat... TM Shear the formulation on a high-speed disperser at 1500 RPM for 10–15 minutes using a Cowles blade. Once complete, then tumble the glass jar containing the formulation overnight under ambient conditions with gentle agitation.

[0201] Choose food-grade approvals available from Covestro AG. BL 2078 / 2 and Curaphen 40-856-B60, available from Bitrez, were used as crosslinking agents for the end-capped IPDI trimer and m-cresin phenolic resin, respectively. Food-grade approved products available from King Industries were also selected. XC-296B is used as an H3PO4 catalyst.

[0202] Table 5. Gold coating formulations based on modified resins and TMCD polyesters

[0203]

[0204] Table 6. Characteristics of Gold Coating

[0205] GF1 100+ 79％ qualified 65％ GF2 100+ 69％ qualified 78％ GF3 100+ 72％ qualified 77％ CGF-1 100+ 60％ fail 97％

[0206] Example 5: Preparation of gold coating formulation (GF 2-5 and CGF 2-3)

[0207] Coating formulations for gold were prepared using modified resins MR2 and MR3 and TMCD polyester resin 1. These three formulations, GF2, CGF2, and CGF3, were prepared using MR2 and resin 1 in ratios of 50 / 50, 65 / 35, and 75 / 25. CGF2 and CGF3 are designated as contrast gold formulations because they failed both the MEK double friction and total distillation tests. Additionally, three other formulations, GF3, GF4, and GF5, were prepared using MR3 and resin 1 in ratios of 50 / 50, 35 / 65, and 20 / 80. The compositions of the formulations are listed in Table 7, and the coating properties are listed in Table 8.

[0208] Table 7. Gold coating formulations based on various ratios of modified resins and TMCD polyesters

[0209]

[0210]

[0211] Table 8. Characteristics of Gold Coating

[0212] GF2 100+ 69％ qualified 78％ CGF-2 58 73％ qualified 52％ CGF-3 35 83％ qualified 34％ GF3 100+ 72％ qualified 77％ GF4 100+ 73％ qualified 74％ GF5 100+ 73％ qualified 76％

[0213] Comparative Example 1: Synthesis of Comparative Modified Polyester Polyols and Comparative Modified Resins (CMR-1)

[0214] This example describes the synthesis of a polyester polyol with lower TMP (2 mol%) and lower OH number (25 mg KOH / g) compared to the modified polyester polyol of the present invention.

[0215] Polyols were produced using a resin-refined reactor setup controlled by automated control software. The composition was prepared using a 2L vessel with a top stirrer and a partial condenser with a top-mounted main condenser and a Dean Stark separator. Approximately 10 wt% (based on reaction yield) of a high-boiling-point azeotropic solvent (A150ND) was used to facilitate the removal of water condensate from the reaction mixture, and a standard paddle stirrer was used to maintain the reaction mixture at a reasonable viscosity level. Isophthalic acid (IPA), adipic acid (AD), 2,2,4,4-tetramethyl-1,3-cyclobutanediol (TMCD), 2-methyl-1,3-propanediol (MP-diol), trimethylolpropane (TMP), and Aromatic 150ND were added to the reactor, which was then fully assembled. After assembling the reactor and covering it with nitrogen, a Fascat 4100 (monobutyltin oxide) catalyst was added through a sampling port. Additional A150ND solvent was added to the Dean Stark separator to maintain a solvent level of approximately 10 wt% in the reactor. Using the set output controlled by an automated system, the reaction mixture was heated from room temperature to 150°C without stirring. Once the reaction mixture was sufficiently fluid, stirring was initiated to promote uniform heating of the mixture. At 150°C, heating control was switched to automatic control, and the temperature was increased to 230°C over a 4-hour period. The reaction was maintained at 230°C, and samples were taken every 1–2 hours after clarification until the desired acid value was reached. The reaction mixture was then further diluted with A150ND to a target of 55% by weight of solids. The solution was filtered through an approximately 250 μm paint filter before use for formulation and application testing. It should be noted that the diol excess was determined based on experience with laboratory reactors and may vary depending on the partial condenser and reactor design used.

[0216]

[0217] Comparative Example 2: Synthesis of Comparative Modified Polyester Polyol (CMR-2)

[0218] This example describes the synthesis of a polyester polyol with low TMCD (22 mol%) and no MP diol compared to the modified polyester polyol of the present invention.

[0219] Polyols were produced using a resin-refined reactor set controlled by automated control software. The composition was prepared using a 2L reactor with a top stirrer and a partial condenser with a top-mounted total condenser and a Dean Stark water separator. Approximately 10 wt% (based on reaction yield) of a high-boiling-point azeotropic solvent (A150ND) was used to facilitate the removal of water condensate from the reaction mixture, and a standard paddle stirrer was used to maintain the reaction mixture at a reasonable viscosity. Isophthalic acid (IPA), purified terephthalic acid (TPA), adipic acid (AD), 2,2,4,4-tetramethyl-1,3-cyclobutanediol (TMCD), 2,2-dimethyl-1,3-propanediol (NPG diol), trimethylolpropane (TMP), and Aromatic 150ND were added to the reactor, which was then fully assembled. After assembling the reactor and covering it with nitrogen, Fascat 4100 (monobutyltin oxide) catalyst was added through a sampling port. Add additional A150ND solvent to the Dean Stark separator to maintain a solvent level of approximately 10 wt% in the reactor. Using the set output controlled by the automated system, heat the reaction mixture from room temperature to 150°C without stirring. Once the reaction mixture is sufficiently fluid, begin stirring to promote uniform heating of the mixture. At 150°C, switch the heating control to automatic control and increase the temperature to 230°C over 4 hours. Maintain the reaction at 230°C and sample every 1–2 hours after clarification until the desired acid value is reached. Then further dilute the reaction mixture with A150ND, targeting 55% solids by weight. Filter the solution through an approximately 250 μm paint filter before use for formulation and application testing. It should be noted that the diol excess is determined based on experience with laboratory reactors and may vary depending on the partial condenser and reactor design used.

[0220]

[0221]

[0222] Comparative Example 3: Comparative Synthesis of Modified Polyester Polyol (CMR-3) (Resin 17, EX4940-014)

[0223] This example describes the synthesis of a polyester polyol with low TMCD (22 mol%) and no MP diol compared to the modified polyester polyol of the present invention.

[0224] Polyols were produced using a resin-refined reactor set controlled by automated control software. The composition was prepared using a 2L reactor with a top stirrer and a partial condenser with a top-mounted main condenser and a Dean Stark water separator. Approximately 10 wt% (based on reaction yield) of a high-boiling-point azeotropic solvent (A150ND) was used to facilitate the removal of water condensate from the reaction mixture, and a standard paddle stirrer was used to maintain the reaction mixture at a reasonable viscosity. Isophthalic acid (IPA), terephthalic acid (TPA), sebacic acid (SA), 2,2,4,4-tetramethyl-1,3-cyclobutanediol (TMCD), 2,2-dimethyl-1,3-propanediol (NPG diol), trimethylolpropane (TMP), and Aromatic 150ND were added to the reactor, which was then fully assembled. After assembling the reactor and covering it with nitrogen, Fascat 4100 (monobutyltin oxide) catalyst was added through a sampling port. Add additional A150ND solvent to the Dean Stark separator to maintain a solvent level of approximately 10 wt% in the reactor. Using the set output controlled by the automated system, heat the reaction mixture from room temperature to 150°C without stirring. Once the reaction mixture is sufficiently fluid, begin stirring to promote uniform heating of the mixture. At 150°C, switch the heating control to automatic control and increase the temperature to 230°C over 4 hours. Maintain the reaction at 230°C and sample every 1–2 hours after clarification until the desired acid value is reached. Then further dilute the reaction mixture with A150ND, targeting 55% solids by weight. Filter the solution through an approximately 250 μm paint filter before use for formulation and application testing. It should be noted that the diol excess is determined based on experience with laboratory reactors and may vary depending on the partial condenser and reactor design used.

[0225]

[0226] Comparative Example 4: Synthesis of Comparative Modified Polyester Polyol (CMR-4)

[0227] This example describes the synthesis of a polyester polyol with lower TMP (2 mol%), lower OH number (16 mg KOH / g), and higher Tg (90 °C) compared to the modified polyester polyol of the present invention.

[0228] Polyols were produced using a resin-refined reactor set controlled by automated control software. The composition was prepared using a 2L reactor with a top stirrer and a partial condenser with a top-mounted total condenser and a Dean Stark water separator. Approximately 10 wt% (based on reaction yield) of a high-boiling-point azeotropic solvent (A150ND) was used to facilitate the removal of water condensate from the reaction mixture, and a standard paddle stirrer was used to maintain the reaction mixture at a reasonable viscosity. Isophthalic acid (IPA), terephthalic acid (TPA), 1,4-cyclohexanedicarboxylic acid (1,4-CHDA), 2,2,4,4-tetramethyl-1,3-cyclobutanediol (TMCD), 1,4-cyclohexanediethanol (CHDM), trimethylolpropane (TMP), and Aromatic 150ND were added to the reactor, which was then fully assembled. After assembling the reactor and covering it with nitrogen, Fascat 4100 (monobutyltin oxide) catalyst was added through a sampling port. Add additional A150ND solvent to the Dean Stark separator to maintain a solvent level of approximately 10 wt% in the reactor. Using the set output controlled by the automated system, heat the reaction mixture from room temperature to 150°C without stirring. Once the reaction mixture is sufficiently fluid, begin stirring to promote uniform heating of the mixture. At 150°C, switch the heating control to automatic control and increase the temperature to 230°C over 4 hours. Maintain the reaction at 230°C and sample every 1–2 hours after clarification until the desired acid value is reached. Then further dilute the reaction mixture with A150ND, targeting 55% solids by weight. Filter the solution through an approximately 250 μm paint filter before use for formulation and application testing. It should be noted that the diol excess is determined based on experience with laboratory reactors and may vary depending on the partial condenser and reactor design used.

[0229]

[0230]

[0231] Comparative Example 5: Synthesis of Comparative Modified Polyester Polyol (CMR-5)

[0232] This example describes the synthesis of a polyester polyol with low TMCD (22 mol%), no MP diol, and no IPA and TPA compared to the modified polyester polyol of the present invention.

[0233] Polyols were produced using a resin-refined reactor setup controlled by automated control software. The composition was prepared using a 2L vessel with a top stirrer and a partial condenser with a top-mounted main condenser and a Dean Stark water separator. Approximately 10 wt% (based on reaction yield) of a high-boiling-point azeotropic solvent (A150ND) was used to facilitate the removal of water condensate from the reaction mixture, and a standard paddle stirrer was used to maintain the reaction mixture at a reasonable viscosity level. 1,4-Cyclohexanedicarboxylic acid (1,4-CHDA), 2,2,4,4-Tetramethyl-1,3-cyclobutanediol (TMCD), 2,2-dimethyl-1,3-propanediol (NPG diol), trimethylolpropane (TMP), and Aromatic 150ND were added to the reactor, which was then fully assembled. After assembling the reactor and covering it with nitrogen, Fascat 4100 (monobutyltin oxide) catalyst was added through a sampling port. Additional A150ND solvent was added to the Dean Stark water separator to maintain a solvent level of approximately 10 wt% in the reactor. Using the set output controlled by an automated system, the reaction mixture was heated from room temperature to 150°C without stirring. Once the reaction mixture was sufficiently fluid, stirring was initiated to promote uniform heating of the mixture. At 150°C, heating control was switched to automatic control, and the temperature was increased to 230°C over a 4-hour period. The reaction was maintained at 230°C, and samples were taken every 1–2 hours after clarification until the desired acid value was reached. The reaction mixture was then further diluted with A150ND to a target of 55% by weight of solids. The solution was filtered through an approximately 250 μm paint filter before use for formulation and application testing. It should be noted that the diol excess was determined based on experience with laboratory reactors and may vary depending on the partial condenser and reactor design used.

[0234]

[0235]

[0236] Comparative Example 6: Comparative Synthesis of Modified Polyester Polyol (CMR-6)

[0237] This example describes the synthesis of a polyester polyol with low TMCD (24 mol%), no MP diol, no TMP, and low OH number (24 mg KOH / g) compared to the modified polyester polyol of the present invention.

[0238] Polyols were produced using a resin-refined reactor set controlled by automated control software. The composition was prepared using a 2L reactor with a top stirrer and a partial condenser with a top-mounted total condenser and a Dean Stark water separator. Approximately 10 wt% (based on reaction yield) of a high-boiling-point azeotropic solvent (A150ND) was used to facilitate the removal of water condensate from the reaction mixture, and a standard paddle stirrer was used to maintain the reaction mixture at a reasonable viscosity. Isophthalic acid (IPA), terephthalic acid (TPA), adipic acid (AD), 2,2,4,4-tetramethyl-1,3-cyclobutanediol (TMCD), 2,2-dimethyl-1,3-propanediol (NPG diol), trimethylolpropane (TMP), and Aromatic 150ND were added to the reactor, which was then fully assembled. After assembling the reactor and covering it with nitrogen, Fascat 4100 (monobutyltin oxide) catalyst was added through a sampling port. Add additional A150ND solvent to the Dean Stark separator to maintain a solvent level of approximately 10 wt% in the reactor. Using the set output controlled by the automated system, heat the reaction mixture from room temperature to 150°C without stirring. Once the reaction mixture is sufficiently fluid, begin stirring to promote uniform heating of the mixture. At 150°C, switch the heating control to automatic control and increase the temperature to 230°C over 4 hours. Maintain the reaction at 230°C and sample every 1–2 hours after clarification until the desired acid value is reached. Then further dilute the reaction mixture with A150ND, targeting 55% solids by weight. Filter the solution through an approximately 250 μm paint filter before use for formulation and application testing. It should be noted that the diol excess is determined based on experience with laboratory reactors and may vary depending on the partial condenser and reactor design used.

[0239]

[0240] Comparative Example 7: Synthesis of Comparative Modified Polyester Polyol (CMR-7)

[0241] This example describes the synthesis of a polyester polyol with low TMCD (24 mol%), no MP diol, no TMP, and low OH number (23 mg KOH / g) compared to the modified polyester polyol of the present invention.

[0242] Polyols were produced using a resin-refined reactor set controlled by automated control software. The composition was prepared using a 2L reactor with a top stirrer and a partial condenser with a top-mounted main condenser and a Dean Stark water separator. Approximately 10 wt% (based on reaction yield) of a high-boiling-point azeotropic solvent (A150ND) was used to facilitate the removal of water condensate from the reaction mixture, and a standard paddle stirrer was used to maintain the reaction mixture at a reasonable viscosity. Isophthalic acid (IPA), terephthalic acid (TPA), sebacic acid (SA), 2,2,4,4-tetramethyl-1,3-cyclobutanediol (TMCD), 2,2-dimethyl-1,3-propanediol (NPG diol), trimethylolpropane (TMP), and Aromatic 150ND were added to the reactor, which was then fully assembled. After assembling the reactor and covering it with nitrogen, Fascat 4100 (monobutyltin oxide) catalyst was added through a sampling port. Add additional A150ND solvent to the Dean Stark separator to maintain a solvent level of approximately 10 wt% in the reactor. Using the set output controlled by the automated system, heat the reaction mixture from room temperature to 150°C without stirring. Once the reaction mixture is sufficiently fluid, begin stirring to promote uniform heating of the mixture. At 150°C, switch the heating control to automatic control and increase the temperature to 230°C over 4 hours. Maintain the reaction at 230°C and sample every 1–2 hours after clarification until the desired acid value is reached. Then further dilute the reaction mixture with A150ND, targeting 55% solids by weight. Filter the solution through an approximately 250 μm paint filter before use for formulation and application testing. It should be noted that the diol excess is determined based on experience with laboratory reactors and may vary depending on the partial condenser and reactor design used.

[0243]

[0244]

[0245] Comparative Example 8: Synthesis of Comparative Modified Polyester Polyol (CMR-8)

[0246] This example describes the synthesis of a polyester polyol with high TCDDM (72 mol%) but within the Tg range compared to the modified polyester polyol of the present invention.

[0247] Polyols were produced using a resin reactor set controlled by automated control software. Compositions were prepared in 3.5 mol scales using a 2L reactor with a top stirrer and a partial condenser with a top total condenser and a Dean Stark water separator. Approximately 10 wt% (based on reaction yield) of high-boiling azeotropic solvents (A150 and A150ND) was used to facilitate the removal of water condensate from the reaction mixture, and a standard paddle stirrer was used to maintain the reaction mixture at a reasonable viscosity. Terephthalic acid (TPA), sebacic acid (SA), and 4,8-bis(hydroxymethyl)tricyclo[5.2.1.0] were added. 2,6 A mixture of decane isomers (TCDDM), 2-methyl-1,3-propanediol (MP glycol), trimethylolpropane (TMP), and Aromatic 150 were added to the reactor and then fully assembled. After assembling the reactor and covering it with nitrogen, Fascat 4100 (monobutyltin oxide) was added through a sampling port. Additional A150 / A150ND solvent was added to a Dean Stark water separator to maintain a solvent level of approximately 10 wt% in the reactor. The reaction mixture was heated from room temperature to 150°C without stirring using the set output controlled by the automated system. Once the reaction mixture was sufficiently fluid, stirring was initiated to promote uniform heating of the mixture. At 150°C, the heating control was switched to automatic control, and the temperature was increased to 230°C over 4 hours. The reaction was maintained at 230°C and sampled every 1–2 hours after clarification until the desired acid value was reached (approximately 3 hours). The reaction mixture was then further diluted with A150ND, targeting a solids weight percentage of 55%. Before use in formulation and application testing, the solution is filtered through a paint filter of approximately 250 μm. It should be noted that the glycol excess is determined based on experience with laboratory reactors and may vary depending on the partial condenser and reactor design used. The glycol:acid ratio is also controlled to achieve the same molecular weight with varying amounts of simpler acids and hydroxyl end groups.

[0248]

[0249]

[0250] Comparative Example 9: Synthesized Comparative Modified Polyester Polyols (CMR1-8)

[0251] The compositions of the modified polyester polyols are listed in Table 9; their resin properties are listed in Table 10.

[0252] Table 9. Comparatively Modified Polyester Polyols Synthesized

[0253]

[0254]

[0255] Table 10. Comparative Resin Properties of Modified Polyester Polyols

[0256]

[0257] Example 10: Comparative Preparation of Gold Paint Formulations (CGF) 2-9)

[0258] Coating formulations for gold finishes were prepared using various comparative modified resins (CMR 1-8) and TMCD polyester (resin 1). Comparative gold formulations (CGF 2-9) prepared from the various comparative modified resins and TMCD polyester are listed in Table 11. Table 12 lists the coating properties of these formulations.

[0259] Prior to formulation, all polyester polyols were diluted to 50 wt% solids in A150ND. Solvent blends were prepared from a mixture of xylene, butanol, and MAK at 30 wt%, 30 wt%, and 40 wt%, respectively. Empty, lidded glass jars were labeled and pre-weighed to record the tare weight. For each formulation, Curaphen 40-856-B60 was weighed separately. BL2078 / 2 XC-296B and solvent blends were added sequentially to the resin solution. Then, in Dispermat... TM Shear the formulation on a high-speed disperser at 1500 RPM for 10–15 minutes using a Cowles blade. Once complete, then tumble the glass jar containing the formulation overnight under ambient conditions with gentle agitation.

[0260] Choose food-grade approvals available from Covestro AG. BL 2078 / 2 and Curaphen 40-856-B60, available from Bitrez, were used as crosslinking agents for the end-capped IPDI trimer and m-cresin phenolic resin, respectively. Food-grade approved products available from King Industries were also selected. XC-296B is used as an H3PO4 catalyst.

[0261] Table 11. Gold coating formulations based on comparative modified resins and TMCD polyesters

[0262]

[0263]

[0264] Table 12. Characteristics of Gold Coating

[0265] CGF-4 100+ 65％ fail 52％ CGF-5 100+ 65％ fail 73％ CGF-6 100+ 67％ fail 68％ CGF-7 59 60％ fail 90％ CGF-8 100+ 63％ fail 75％ CGF-9 100+ 65％ fail 85％ CGF-10 100+ 64％ fail 65％ CGF-11 100+ 79％ fail 70％

[0266] The present invention has been described in detail with reference to the embodiments disclosed herein; however, it should be understood that variations and modifications can be made within the spirit and scope of the invention.

Claims

1. A coating composition for metal packaging applications, comprising: a. 2,2,4,4-Tetramethyl-1,3-cyclobutanediol (TMCD) polyester, which is the reaction product of a monomer, said monomer comprising: i. Based on the total number of moles in (a) and (i-iv), the amount of TMCD is 35 mol%-80 mol%. ii. 20 mol% to 65 mol% of 1,4-cyclohexanediethanol (1,4-CHDM) based on the total number of moles of (a) (i-iv). iii. Based on the total molar number of (a) and (i-iv), the amount of diols that are different from TMCD and different from 1,4-CHDM, ranging from 0 mol% to 25 mol%. iv. Based on the total number of moles of (a) and (i-iv), 0 mol%-5 mol% of trimethylolpropane (TMP). v. Based on the total number of moles of (a) and (v-vi), 90 mol%-100 mol% of aromatic diacids. vi. Based on the total number of moles of (a) and (v-vi), aliphatic diacids in amounts ranging from 0 mol% to 10 mol%. b. A modified polyester, which is a reaction product of a monomer, said monomer comprising: i. Based on the total molar number of (b)(i-iii), 30 mol%-55 mol% of cyclic diols, ii. Based on the total number of moles of (b)(i-iii), 30 mol%-67 mol% of 2-methyl-1,3-propanediol (MP diol). iii. Based on the total number of moles in (b)(i-iii), the amount of trimethylolpropane (TMP) is 3 mol% to 20 mol%. iv. Based on the total molar amount of (b) (iv-v), 55 mol%-85 mol% of terephthalic acid (TPA) or isophthalic acid (IPA) or a mixture thereof, v. Based on the total molar number of (b) and (iv-v), 15 mol%-45 mol% of aliphatic diacids, c. One or more crosslinking agents selected from the group consisting of: methyl phenolic resins, isocyanates, and amino resin crosslinking agents. Based on the total weight of (a) and (b), the amount of TMCD polyester (a) is 40wt%-95wt%, and the amount of modified polyester (b) is 5wt%-60wt%. The TMCD polyester has a glass transition temperature (Tg) of 60 to 110°C, an acid value of 0 to 8 mg KOH / g, a hydroxyl value of 3 to 25 mg KOH / g, a number-average molecular weight of 5,000 to 20,000 g / mol, and a weight-average molecular weight of 10,000 to 100,000 g / mol; the modified polyester has a Tg of 20 to 50°C, an acid value of 0 to 10 mg KOH / g, a hydroxyl value of 30 to 60 mg KOH / g, a Mn of 2,000 to 10,000 g / mol, and a Mw of 10,000 to 150,000 g / mol; and the coating has a solvent resistance of greater than 70 MEK bi-friction as measured by ASTM D7835, and a wedge bending resistance (% qualified) of 60-100 as measured by ASTM D3281.

2. The coating composition according to claim 1, wherein the aromatic diacid (a) and (v) are IPA, TPA, or a mixture thereof.

3. The coating composition according to claim 1, wherein the TMCD polyester (a) has a hydroxyl value of 10-25 mg KOH / g.

4. The coating composition according to claim 1, wherein the Tg of the TMCD polyester (a) is 70 to 110°C.

5. The coating composition according to claim 1, wherein the cyclic diol (b)(i) is selected from TCDDM, TMCD and mixtures thereof.

6. The coating composition according to claim 1, wherein the aliphatic diacid (b) (v) is selected from diacid, sebacic acid, or a mixture thereof.

7. The coating composition according to claim 1, wherein the modified polyester (b) has a hydroxyl value of 40-50 mg KOH / g.

8. The coating composition according to claim 1, wherein the modified polyester (b) has a Tg of 20 to 40°C.

9. The coating composition according to claim 1, wherein the amount of the TMCD polyester (a) is 45wt%-65wt% and the amount of the modified polyester (b) is 35wt%-55wt% based on the total weight of (a) and (b).

10. The coating composition according to claim 1, wherein the crosslinking agent (c) is a methyl phenolic resin, an isocyanate, or a mixture thereof.

11. The coating composition according to claim 10, wherein the crosslinking agent (c) is a mixture of methyl phenolic resin and isocyanate, and wherein, based on the total weight of the crosslinking agent, the amount of methyl phenolic resin is 70wt%-90wt% and the amount of isocyanate is 10wt%-30wt%.

12. The coating composition according to claim 1, wherein the total amount of TMCD polyester (a) and the modified polyester (b) is 50-90 wt% based on the total weight of (a), (b) and (c), and the amount of the crosslinking agent (c) is 10-50 wt%.

13. The coating composition according to claim 1, wherein: Based on the total weight of (a), (b), (c), and (d), the 2,2,4,4-tetramethyl-1,3-cyclobutanediol (TMCD) polyester is present in an amount of 30-40 wt%. Based on the total weight of (a), (b), (c), and (d), the modified polyester is present in an amount of 30-40 wt%. c. Based on the total weight of (a), (b), (c), and (d), 15-30 wt% of methyl phenolic resin, and d. Based on the total weight of (a), (b), (c) and (d), 5-15 wt% of isophorone diisocyanate (IPDI).

14. An article thereof, at least a portion of which is coated with the coating composition of claim 1.

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