Formaldehyde-free crosslinkable composition

Abstract

The invention relates to reaction products H of at least one cyclic urea U, at least one polyfunctional aldehyde A and at least one polyol P, to processes for their preparation and to compositions comprising them.

Description

[0001] This application is a divisional application of application number 201680074340.6. Technical Field

[0002] The present invention relates to a reaction product of a cyclic urea and a multifunctional aldehyde, and a method for preparing the same. The present invention also relates to a coating composition comprising the reaction product, and a method for providing a coating on a substrate using the coating composition. Background Art

[0003] Crosslinking agents or crosslinkers based on amino resins and coating compositions prepared with these crosslinkers are well known in the art and have been used for more than half a century in a variety of applications, including general industrial coatings, automotive coatings, coil coatings, powder coatings, baking enamels and wood finishes. These crosslinkers are based on the reaction products of aldehydes (usually formaldehyde) and amines, amides, polyurethanes or amidine compounds (collectively referred to as aminoplast formers) such as melamine, guanamine, urea and substituted ureas. The main disadvantage of coatings based on these amino resins is the emission of formaldehyde during the curing process.

[0004] Various crosslinking compositions based on combinations of aminoplast formers and aldehydes other than formaldehyde have been developed.

[0005] Formaldehyde-free crosslinking resins for textiles based on reaction products of cyclic ureas with polyfunctional aldehydes having at least two aldehyde groups per molecule have been described in U.S. Pat. No. 4,332,586 and U.S. Pat. No. 4,284,758. Both U.S. Pat. Nos. 4,332,586 and 4,284,758 disclose the preparation and use of alkylated glyoxal and cyclic urea condensates as crosslinking agents for textiles. However, the viscosity of the etherified adducts obtained increases by about 4.6 times after storage at 48° C. for 10 weeks.

[0006] WO2012044547 and WO2012044549 describe etherified and non-etherified reaction products of cyclic ureas and polyfunctional aldehydes, respectively.

[0007] WO2013142787 discloses mixed resins or reaction products of cyclic alkylene ureas with multifunctional aldehydes and other "aminoplast formers". Examples of such aminoplast formers include linear and cyclic urea derivatives, amines, acid amines, polyurethanes, amino-functional triazine derivatives, and the like.

[0008] US Patent 8,133,952 describes the use of cyclic ureas as blocking agents for products based on the use of polyvinyl alcohol and polyaldehyde crosslinkers. The patent relates to formaldehyde-free curable aqueous compositions useful as binders for nonwoven products requiring the presence of high molecular weight polyvinyl alcohol.

[0009] US Patent No. 4,625,029 discloses cyclic urea / glyoxal / polyol condensates used as formaldehyde-free crosslinking agent resins for cellulosic fabrics. The polyols used are, for example, ethylene glycol, diethylene glycol, and the like.

[0010] However, despite many efforts, there is still a need to develop formaldehyde-free crosslinking compositions based on reaction products of cyclic alkylene ureas and polyfunctional aldehydes which, when used in coating compositions, show satisfactory performance, especially with respect to storage stability and color stability of heat-aged films.

[0011] Technical issues

[0012] The object of the present invention is to provide crosslinking compositions based on reaction products of cyclic alkylene ureas and polyfunctional aldehydes which, when used in coating formulations, release no or very limited amounts of formaldehyde, which exhibit improved storage stability, preferably without the addition of any organic solvents, and which improve the color stability of heat-aged films of the coatings. SUMMARY OF THE INVENTION

[0013] This object is achieved by providing a reaction product H of at least one cyclic urea U, at least one polyfunctional aldehyde A and at least one polyol P.

[0014] In fact, it has been found that the incorporation of at least one polyol P, preferably a short-chain polyol such as a diol, as a coreactant into the cyclic urea U-polyfunctional aldehyde A condensate surprisingly provides a crosslinker with improved shelf life even without the use of solvents, and further improves the color stability of the heat aged films of the coatings, especially when prepared in the presence of organic acids. Preferably, the polyol P used is not an orthopolyol.

[0015] Another aspect of the present invention is to provide a reaction product H of at least one cyclic urea U, at least one polyfunctional aldehyde A and at least one polyol P, obtained in the presence of at least one acid catalyst C, preferably an organic acid catalyst. In fact, it has surprisingly been found that when preparing the reaction product H, the presence of an organic acid catalyst C allows to further improve the storage stability of the coating composition comprising said reaction product H and the color stability of the heat aged film.

[0016] The method for preparing the reaction product H according to the present invention preferably comprises the following steps:

[0017] a) mixing at least one cyclic urea U with at least one polyfunctional aldehyde A to carry out an addition reaction in the presence of at least one base B, wherein the base B does not react with any of the following: the polyfunctional aldehyde A, the cyclic urea U and the reaction product H, and the at least one polyol P.

[0018] Another aspect of the invention relates to a coating composition comprising the reaction product H and optionally at least one crosslinkable resin and / or optionally water and / or optionally at least one organic solvent, wherein the crosslinkable resin may preferably be an oligomeric or polymeric material having at least one functional group having an active hydrogen atom, preferably selected from hydroxyl functional groups, acid functional groups, carboxylic acid functional groups, amide functional groups, amino functional groups, imino functional groups, imide functional groups, thiol functional groups, phosphine functional groups and carbamate functional groups. According to one aspect of the invention, the coating composition comprises the reaction product H and at least one crosslinkable resin and optionally water and / or optionally at least one organic solvent.

[0019] One aspect of the present invention is to provide an aqueous coating composition comprising a mixture of reaction product H, optionally at least one crosslinkable resin, and / or optionally water and / or optionally at least one organic solvent and / or optionally additives known to those skilled in the art. According to one embodiment, the aqueous coating composition comprises a mixture of reaction product H and at least one crosslinkable resin and / or optionally water and / or optionally at least one organic solvent and / or optionally additives.

[0020] Another aspect of the present invention is to provide a method for using the reaction product H as a crosslinking agent, in particular a coating method, which method comprises mixing the reaction product H with optionally at least one crosslinkable resin and / or optionally with water and / or optionally with at least one organic solvent, homogenizing and applying the homogenized mixture to a substrate. According to one embodiment, the method for using the reaction product H as a crosslinking agent comprises mixing the reaction product H with at least one crosslinkable resin and / or optionally with water and / or optionally with at least one organic solvent, homogenizing and applying the homogenized mixture to a substrate.

[0021] DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] The invention provides a reaction product H of at least one cyclic urea U, at least one polyfunctional aldehyde A and at least one polyol P. The reaction product H is obtained from the reaction of at least one cyclic urea U, at least one polyfunctional aldehyde A and at least one polyol P.

[0023] The preferred ratio of the amount of substance of the at least one multifunctional aldehyde A to the amount of substance of the at least one cyclic urea U used to prepare the reaction product H is 0.8:1 to 1.4:1 molar equivalents, more preferably 1.25:1 to 1.1:1 molar equivalents.

[0024] The preferred ratio of the amount of substance of the at least one polyol P to the amount of substance of the at least one cyclic urea U used in preparing the reaction product H is from 0.01:1 to 1:1, more preferably from 0.1:1 to 0.6:1 molar equivalents.

[0025] According to one specific embodiment, when preparing the reaction product H, the most preferred ratio of the amount of substance of the multifunctional aldehyde A to the amount of substance of the cyclic urea U to the amount of substance of the polyol P is 1.18:1.00:0.40 molar equivalents.

[0026] The ratio of the amount of polyol P reacted or bound in the reaction product H to the amount of cyclic urea U in the reaction product H is preferably at least 0.01 mol / mol, more preferably 0.05-1 mol / mol, and most preferably 0.19-0.6 mol / mol. The amount of polyol P reacted into the reaction product H is determined as the ratio [n(-polyol P) / n(U)] of the amount of polyol species bound to the amount of cyclic urea U species chemically bound in the reaction product [n(U)].

[0027] The reaction product H shows a low imino content or a low level of unreacted cyclic urea U and a low level of residual polyfunctional aldehyde A, even when a high molar feed ratio (greater than 1.01) of polyfunctional aldehyde A to cyclic urea U is used.

[0028] The polyfunctional aldehyde A has the general formula OHC-R'-CHO, where R' can be a direct bond or an aliphatic divalent radical, which can be linear, branched or cyclic and can have 1 to 20 carbon atoms, both options for R' leading to a divalent aldehyde having exactly two -CHO groups, or an aliphatic divalent radical, which can be linear, branched or cyclic and can have 1 to 20 carbon atoms, and carries at least one additional aldehyde group -CHO, the latter option leading to a trivalent or polyvalent aldehyde having at least three aldehyde groups.

[0029] In the context of the present invention, "multifunctional" is used to denote molecules having more than one functional group, preferably at least two aldehyde groups. Preferred aldehydes are divalent aliphatic aldehydes, in particular glyoxal, malonic acid dialdehyde, succinaldehyde and glutaraldehyde. Particularly preferred is glyoxal. Mixtures of these aldehydes can also be used, preferably mixtures containing at least 50% glyoxal by mass, particularly preferably at least 70% glyoxal. Glyoxal can be used in aqueous solution, anhydrous solid (because its melting temperature is 15°C, the anhydrous solid must be cooled to obtain), or in the form of its dimer or trimer, optionally in the form of a solid hydrate such as a dihydrate, or in the form of an addition product with a sulfite or bisulfite that decomposes under acidic conditions for use in the present invention. It has been found that when aqueous glyoxal purified by methods known to those skilled in the art is used, the color and stability of the reaction product with a cyclic urea are improved. Purification can be accomplished by conventional methods, for example using activated carbon or by using ion exchange resins or by treatment with metal carbonates or continuous liquid-liquid countercurrent extraction.

[0030] The cyclic urea U that can be used according to the invention has at least one unsubstituted -CO-NH- group. The cyclic urea U is preferably a cyclic alkylene urea. These cyclic ureas U are cycloaliphatic or bicyclic aliphatic compounds having -NH-CO-NH- structural elements in the ring structure, the total number of ring atoms being preferably 5 to 7 (ethylene urea, 1,2-propylene urea, 1,3-propylene urea, 1,4-butylene urea or tetramethylene urea). Particularly preferred are ethylene urea or mixtures containing ethylene urea, in particular mixtures containing at least 50% ethylene urea by mass. In the case of binary compounds, the simplest structure is glycoluril or acetylene diurea. These cyclic ureas may be substituted, preferably substituted by alkyl groups on N- or C- atoms or both, the alkyl residue preferably having 1-4 carbon atoms. At least one nitrogen atom must remain unsubstituted to enable it to react with aldehyde-functional molecules. Preferably, the at least one cyclic urea U is selected from U1, which is composed of ethylene urea, 1,2-propylene urea, hydantoin (also known as ethanol urea), oxalyl urea (also known as oxalyl urea) and glycoluril, and U2 is selected from cyclic urea U1 consisting of cyclic urea U1 additionally having at least one substituent R3 on at least one nitrogen or carbon atom of the cyclic urea U1, with the proviso that at least one nitrogen atom is unsubstituted and the substituent R3 is selected from straight chain, branched and cycloalkyl groups having 1 to 10 carbon atoms.

[0031] It has been found that when purified cyclic ureas are used instead of commercial qualities, for example, commercial ethylene ureas with a purity of about 96% (the mass fraction of ethylene urea in one commercial product is (96.0 ± 0.5)%), the color and stability of the reaction product with a polyfunctional aldehyde are improved. Purification can be accomplished by conventional methods, such as recrystallization, extraction, adsorption and ion exchange reactions, distillation or sublimation or complexation, preferably by melt crystallization, which methods have low energy consumption, high space-time yield, consistent quality. Cyclic alkylene ureas can also be generated in situ by reacting a compound having two or more>NH groups with an at least difunctional aldehyde, for example by reacting a diamine or a diamide with a dialdehyde. An example is dihydroxyethylene urea formed by the reaction of urea with glyoxal.

[0032] Particularly preferred combinations of cyclic ureas U and polyfunctional aldehydes A are the reaction of glyoxal with ethylene urea and optionally mixtures of glyoxal or ethylene urea or both with other polyfunctional aldehydes and / or other cyclic ureas.

[0033] The at least one polyol P refers to a polyhydroxy-functional compound having at least two hydroxyl groups and can be selected from a variety of linear and non-linear diols, triols, tetraols, including ethylene glycol, diethylene glycol, 1,3-propylene glycol, 1,2-propylene glycol, butanediol, hexanediol, 2-methyl-1,3-propanediol (MP diol), 2-ethyl-1,2-hydroxymethyl-1,3-propanediol, trimethylolpropane (TMP), tris(hydroxymethyl)ethane (THME), cyclohexanedimethanol (CHDM), neopentyl glycol (NPG), trimethylpentanediol, dimethylolpropionic acid (DMPA), pentaerythritol and the like compounds and mixtures thereof. The polyol used in the present invention is preferably not based on derivatives of starch or cellulose or high molecular weight polyvinyl alcohol.

[0034] Preferred are polyols having a molecular weight of less than or equal to 1000 Daltons. Particularly preferred are polyols having a molecular weight of less than or equal to 500 Daltons and having at least two or more primary hydroxyl functional groups. Other functional groups such as carboxylic acid groups, amide groups, carbamates, etc. may optionally be present in the preferred polyols having at least two primary hydroxyl functional groups.

[0035] The at least two primary hydroxyl functional groups in the polyol P are preferably non-vicinal and separated by at least one carbon atom, which may be primary, secondary or tertiary in nature.

[0036] Suitable polyols P are, in particular, hexanediol, 2-methyl-1,3-propanediol (MP diol), 2-ethyl-1,2-hydroxymethyl-1,3-propanediol, trimethylolpropane (TMP), tris(hydroxymethyl)ethane (THME), cyclohexanedimethanol (CHDM), neopentyl glycol (NPG), trimethylpentanediol, dimethylolpropionic acid (DMPA), pentaerythritol, and the like, and mixtures thereof.

[0037] According to one particular embodiment, the at least one polyol P is chosen from: 2-methyl-1,3-propanediol (MP diol), 2-ethyl-1,2-hydroxymethyl-1,3-propanediol, trimethylolpropane (TMP) and 1,6-hexanediol and mixtures thereof.

[0038] A particularly preferred polyol is 2-methyl-1,3-propanediol (eg MP 500 from Lyondellbasell) which has a non-linear structure with two primary hydroxyl groups. Glycol).

[0039] According to a specific embodiment of the present invention, the reaction product H is obtained by the reaction of at least one multifunctional aldehyde A, at least one cyclic urea U and at least one polyol P selected from the group consisting of 2-methyl-1,3-propanediol (MP diol), 2-ethyl-1,2-hydroxymethyl-1,3-propanediol, trimethylolpropane (TMP), 1,6-hexanediol, preferably 2-methyl-1,3-propanediol (MP diol). The reaction product H can preferably be obtained by the reaction of ethylene urea, glyoxal and 2-methyl-1,3-propanediol (MP diol).

[0040] Reaction product H can also be obtained in the presence of an acid catalyst C and preferably an organic acid catalyst. In fact, it was surprisingly found that the use of an organic acid catalyst C to prepare reaction product H leads to a higher conversion, i.e. a higher content of reacted polyol P. This results in the formation of reaction product H which exhibits excellent properties and shows improved storage stability and improved film color stability in surface coating applications.

[0041] According to one embodiment, the reaction product H is obtained by reacting at least one cyclic urea U, at least one multifunctional aldehyde A and at least one polyol P in the presence of at least one acid catalyst C, preferably at least one organic acid catalyst, most preferably citric acid. A preferred combination is the reaction product H of at least one cyclic urea U, at least one multifunctional aldehyde A and at least one 2-methyl-1,3-propanediol (MP diol) in the presence of citric acid. The most preferred combination refers to the reaction product H of at least one ethylene urea, at least one glyoxal and at least one 2-methyl-1,3-propanediol (MP diol) in the presence of citric acid.

[0042] Preferred organic acid catalysts C are: citric acid, succinic acid, lactic acid, tartaric acid and mixtures thereof. The most preferred organic acid catalyst C is citric acid.

[0043] When an acid catalyst C, preferably an organic acid catalyst, is used to prepare the reaction product H, the ratio of the acid catalyst C to the cyclic urea U may preferably be in the range of 0.0001-0.1 mole of acid catalyst C per mole of cyclic urea U. Typically, 0.005 mole of acid catalyst C per mole of cyclic urea U. The amount of acid catalyst C added to the mixture should allow a pH of the reaction mixture <5, preferably pH <4, more preferably a pH of 2.9-3.6 to be achieved.

[0044] The reaction product H may be etherified or non-etherified. Preferably, the reaction product H is non-etherified.

[0045] In the process of preparing the reaction product H, a hydroxyl group (-OH) is generated in the addition reaction of at least one cyclic urea U and at least one multifunctional aldehyde A, which is bound to the carbonyl carbon atom of the aldehyde molecule. This hydroxyl group (-OH) can further condense or react with a monofunctional alcohol R-OH containing a primary or secondary hydroxyl function, wherein R is C 1 -C 12 Alkyl, the monofunctional alcohol is, for example, methanol, ethanol, isopropanol, n-butanol.

[0046] This reaction of the hydroxyl group (—OH) in the reaction product H with the monofunctional alcohol R—OH results in the formation of an alkoxy group (—OR) in the reaction product H.

[0047] The degree of etherification is determined by the ratio [n(-OR) / n(U)] of the amount of the alkoxyl group as a substituent chemically bonded to the aldehyde carbon atom of the polyfunctional aldehyde A in the polyfunctional aldehyde A-cyclic urea U condensate [n(-OR)] to the amount of the cyclic urea U chemically bonded in the reaction product H [n(U)].

[0048] "Etherification" means that the reaction product H is further reacted with at least one monofunctional alcohol R-OH containing primary or secondary hydroxyl groups (e.g., C 1 -C 12 alcohol or a mixture thereof) condense or react. Preferred C 1 -C 12 The alcohol is methanol, ethanol, isopropanol, n-butanol or a mixture thereof. The reaction product H may be completely etherified or partially etherified. Etherification with methanol, ethanol, isopropanol or a mixture of methanol and ethanol or a mixture of methanol and isopropanol or a mixture of methanol, ethanol and isopropanol will provide a crosslinkable composition that is miscible with water and is therefore suitable for waterborne coating applications. Etherification with n-butanol or a mixture of n-butanol and methanol will provide a crosslinkable composition that is immiscible with water and is therefore suitable for solventborne coating applications. As for the etherified product, the degree of etherification is greater than or equal to 0.01 mol / mol.

[0049] "Non-etherified" means a product that does not further condense or react with at least one monofunctional alcohol R-OH containing primary or secondary hydroxyl functions (e.g. methanol, ethanol, isopropanol, n-butanol, etc.). Thus, the reaction product H does not contain any alkoxy groups (-OR). For the non-etherified products of the present invention, the degree of etherification corresponding to the aforementioned ratio is less than 0.01 mol / mol, preferably 0.001 mol / mol.

[0050] The present invention also relates to a method for preparing the reaction product H, which comprises the following steps:

[0051] a) mixing at least one cyclic urea U with at least one polyfunctional aldehyde A for addition reaction in the presence of at least one base B which does not react with any of the polyfunctional aldehyde A, the cyclic urea U, and the reaction product H and the at least one polyol P.

[0052] The at least one base B is preferably a commonly used alkali metal hydroxide such as NaOH, KOH, NH 4 OH and various tertiary amines such as triethylamine, triisopropylamine, dimethylethanolamine, methyldiethanolamine, etc. The at least one base B is added in an amount to reach a pH of 5, more preferably a pH of 6, at the end of step a) or during step a). The at least one base B may be added in an amount to reach a pH of 5.0 to 8.0, preferably 5.5 to 7.5, more preferably 6.1-6.4 at the end of step a).

[0053] When comprising also mixing at least one polyol P, the reaction mixture of step a) may also be heated to 21-80°C, more preferably 30-55°C, most preferably 35-50°C.

[0054] When it involves also mixing at least one polyol P, the reaction time of step a) may preferably be 0.5 to 8 hours, more preferably 1 to 4 hours.

[0055] During the preparation of the reaction product H, an addition reaction is carried out between at least one cyclic urea U and at least one polyfunctional aldehyde A. According to one embodiment, the addition reaction can be carried out in a pH range of greater than 7.5, which is referred to as a "basic" medium, or in a pH range of 4.5-7.5, which is referred to as a "weakly acidic to neutral" medium, and can also be carried out in a pH range of less than 4.5, which is referred to as an "acidic" medium. The condensate or oligomer chain formed is then reacted with at least one polyol P, resulting in the incorporation of at least one polyol P into and on the backbone of the condensate or oligomer chain of at least one cyclic urea U and at least one polyfunctional aldehyde A. The reaction of at least one polyol P can be enhanced by using a more acidic medium, and is therefore preferably carried out in the presence of an acid catalyst C, preferably an organic acid catalyst. At the end of the reaction of at least one polyol P with the condensate of polyfunctional aldehyde A and cyclic urea U, the reaction product H is obtained.

[0056] The multifunctional aldehyde A, the cyclic urea U and the polyol P can be preferably mixed in the following ratio to prepare the reaction product H:

[0057] The ratio of the amount of substance of the polyfunctional aldehyde A used to prepare the reaction product H to the amount of substance of the cyclic urea U is preferably 0.8:1 to 1.4:1 molar equivalents, more preferably 1.25:1 to 1.1:1 molar equivalents.

[0058] The ratio of the amount of substance of the polyol P to the amount of substance of the cyclic urea U may preferably be from 0.01:1 to 1:1, more preferably from 0.1:1 to 0.6:1 molar equivalents.

[0059] According to one specific embodiment, the most preferred ratio of the amount of substance of the polyfunctional aldehyde A to the amount of substance of the cyclic urea U to the amount of substance of the polyol P is 1.18:1.00:0.40.

[0060] The reaction product H obtained at the end of the process preferably exhibits a ratio of the amount of at least one bound (or reacted) polyol P to the amount of at least one cyclic urea U of at least 0.01 mol / mol, more preferably this ratio is from 0.05 to 1 mol / mol, most preferably this ratio is from 0.19 to 0.6 mol / mol.

[0061] The at least one polyol P refers to a polyhydroxy-functional compound having at least two hydroxyl groups, and can be selected from a variety of linear and non-linear diols, triols, and tetraols, including ethylene glycol, diethylene glycol, 1,3-propylene glycol, 1,2-propylene glycol, butanediol, hexanediol, 2-methyl-1,3-propanediol (MP diol), 2-ethyl-1,2-hydroxymethyl-1,3-propanediol, trimethylolpropane (TMP), tris(hydroxymethyl)ethane (THME), cyclohexanedimethanol (CHDM), neopentyl glycol (NPG), trimethylpentanediol, dimethylolpropionic acid (DMPA), pentaerythritol and the like. Suitable polyols P are, in particular, hexanediol, 2-methyl-1,3-propanediol (MP diol), 2-ethyl-1,2-hydroxymethyl-1,3-propanediol, trimethylolpropane (TMP), tris(hydroxymethyl)ethane (THME), cyclohexanedimethanol (CHDM), neopentyl glycol (NPG), trimethylpentanediol, dimethylolpropionic acid (DMPA), pentaerythritol and the like.

[0062] Preferred polyols P are selected from polyols P having at least two primary hydroxyl groups, the polyols P being selected from 2-methyl-1,3-propanediol (MP diol), 2-ethyl-1,2-hydroxymethyl-1,3-propanediol, trimethylolpropane (TMP) and 1,6-hexanediol, more preferably at least one polyol P is 2-methyl-1,3-propanediol (MP diol).

[0063] The preferred acid catalyst C is an organic acid catalyst, which may be selected from citric acid, succinic acid, lactic acid, tartaric acid and mixtures thereof. The most preferred organic acid catalyst C is citric acid.

[0064] According to a particular embodiment of the process, at least one polyol P is mixed in a subsequent step b). In this case, the process for preparing the product H comprises the following steps:

[0065] a) mixing at least one cyclic urea U with at least one polyfunctional aldehyde A to carry out an addition reaction in the presence of at least one base B that does not react with any of the polyfunctional aldehyde A, the cyclic urea U, and the reaction product H,

[0066] -b) admixing at least one polyol P.

[0067] This means that the at least one polyol P can be mixed together with the polyfunctional aldehyde A and the cyclic urea U in the presence of at least one base B, or can be mixed in a subsequent step b).

[0068] When at least one polyol P is not added in step a) but is added in the subsequent step b), the mixture of step a) may preferably be heated to 21°C to less than 80°C, more preferably 35-50°C.

[0069] Then, step b) consisting of the reaction with at least one polyol P can preferably be carried out at a temperature of 25-100° C., more preferably 40-55° C. Step b) is preferably carried out for a time of 1-8 hours, more preferably about 4 hours.

[0070] According to a specific embodiment, the method for preparing the reaction product H may further include:

[0071] - admixture of at least one acid catalyst C, preferably an organic acid catalyst.

[0072] Preferably, when used, the acid catalyst C can be mixed in step b) together with the at least one polyol P. When the at least one polyol P is mixed with the at least one polyfunctional aldehyde A and the cyclic urea U in step a), the at least one acid catalyst C can be mixed in the subsequent step b').

[0073] A variant of the process for preparing the reaction product H comprises the following steps:

[0074] a) mixing at least one cyclic urea U with at least one polyfunctional aldehyde A to carry out an addition reaction in the presence of at least one base B which does not react with any of the polyfunctional aldehyde A, the cyclic urea U and the reaction product H,

[0075] -b) mixing at least one polyol P and at least one acid catalyst C, preferably an organic acid catalyst.

[0076] Yet another variant of the method for preparing the reaction product H comprises the following steps:

[0077] a) mixing at least one cyclic urea U with at least one polyfunctional aldehyde A for addition reaction in the presence of at least one base B which does not react with any of the polyfunctional aldehyde A, the cyclic urea U and the reaction product H and the at least one polyol P,

[0078] -b') admixing at least one acid catalyst C, preferably an organic acid catalyst.

[0079] At least one acid catalyst C, preferably an organic acid catalyst, is added in the following ratios: The ratio of acid catalyst C to cyclic urea U may preferably be in the range of 0.0001-0.1 mol of acid catalyst C per mol of cyclic urea U. Typically, 0.005 mol of acid catalyst C per mol of cyclic urea U. The pH obtained at the end of step b) or b') is preferably <5, more preferably <4, most preferably 2.9-3.6.

[0080] According to one embodiment, there may be a resting time of 5 minutes to 4 hours between steps a) and b) or between steps a) and b').

[0081] According to a specific embodiment, water can be added or removed from the mixture obtained in step a). In particular, water can be preferably removed by distillation.

[0082] The method may also comprise an additional step c) of mixing an inorganic base at the end of the reaction of at least one polyol P, usually after about 4 hours of reaction. In this case, the amount of inorganic base added is such that the pH of the mixture containing the reaction product H is raised to above 5, more preferably to above 6. The inorganic base is preferably selected from the group consisting of commonly used alkali metal hydroxides, such as NaOH, KOH, NH 4 OH, and various tertiary amines, such as triethylamine, triisopropylamine, dimethylethanolamine, methyldiethanolamine, etc.

[0083] According to one specific embodiment, the process for preparing the reaction product H may include an optional etherification step d). The etherification step d) consists of: - adding at least one monofunctional alcohol R-OH and etherifying under acidic conditions. The etherification step is carried out in the presence of an acid catalyst AC. The acid catalyst AC may be selected from nitric acid, sulfuric acid, hydrochloric acid, phosphoric acid, etc. and mixtures thereof. The etherification step d) is carried out at a pH of 5.0-1.5, more preferably 3.0-2.0.

[0084] The etherification step may be repeated one or more times. These repeated etherification steps may be accomplished by simply adding additional alcohol and optionally other acid catalysts AC to the reaction mixture and continuing the reaction, or the reaction mixture may be cooled, neutralized, unreacted alcohol and optionally water removed after one etherification step, and then additional alcohol and acid catalysts AC may be added for the following etherification step. When the etherification step is repeated, the etherification step may be performed with the same monofunctional alcohol or with different alcohols. The at least one monofunctional alcohol may preferably be selected from: C 1 -C 12 , preferably C 1 -C 6 Alcohol or a mixture thereof. Preferred C 1 -C 6 The alcohol is methanol, ethanol, isopropanol, n-butanol or a mixture thereof.

[0085] According to a specific embodiment, the method may optionally include an additional step e) of adding water or removing water from the mixture comprising the reaction product H. The water removed during the distillation process may optionally be replaced in whole or in part by an organic solvent. When such a solvent is used, the solvent is hydrophilic in nature. Examples of such solvents include glycol ethers, etc., including but not limited to methoxypropanol. Step e) may be performed to adjust the solids content.

[0086] The process may further comprise an optional step f) of cooling the reaction mixture comprising the reaction product H. Step f) may be performed, for example, by removing the heat source or applying external cooling conditions or any other method known to a person skilled in the art.

[0087] The reaction product H can be separated by an optional centrifugation or filtration step g) to remove any solid residues; filtration can be carried out using a simple filter medium or a filter medium embedded with activated carbon.

[0088] Any of the aforementioned optional steps c) to g) may be implemented alone or in any combination in the process of the present invention.

[0089] Reaction product H can be used as a crosslinking agent in a crosslinkable composition, typically a formaldehyde-free crosslinking agent.

[0090] The reaction product H can be used alone or in combination with at least one additional crosslinking agent (X) as a crosslinking agent in the crosslinkable composition. When used in combination with an additional crosslinking agent (X), the reaction product H is preferably used together with an amino resin crosslinking agent.

[0091] When a mixture of such a reaction product H and at least one further crosslinking agent (X) is used, in the case of using more than one of these crosslinking agents (X), the ratio of the mass m(H) of the reaction product H to the mass m(X) or the total mass m(X tot) of all crosslinking agents (X) in the mixture is 1 / 99-99 / 1, preferably 10 / 90-90 / 10, particularly preferably 30 / 70-70 / 30. If not explicitly stated otherwise, the mass m used herein generally represents the mass of the active ingredient, and not the mass of the solution containing the active ingredient.

[0092] The at least one crosslinking agent (X) may be selected from:

[0093] - (X1) the reaction product of an aminotriazine with at least one aldehyde selected from aliphatic monoaldehydes and polyfunctional aliphatic aldehydes n having the structure Y(CHO), wherein Y is an n-functional aliphatic residue and n is greater than 1,

[0094] - (X2) reaction products of urea and / or cyclic urea with aliphatic monoaldehydes,

[0095] - (X3) reaction products of urea and / or cyclic urea with aliphatic dialdehydes,

[0096] -(X4) alkoxycarbonylaminotriazine, and / or

[0097] -(X5) Reaction products of phenols and aliphatic monoaldehydes.

[0098] The crosslinker comprising the reaction product H, optionally in combination with at least one of the crosslinkers (X1) to (X5), can be applied as such, preferably to a heat-sensitive substrate selected from paper, textiles, wood, synthetic wood, leather or cellulosic materials, for which purpose they can be mixed with at least one of a catalyst, a filler, a wetting agent, a solvent and a diluent and applied to the substrate.

[0099] The present invention also relates to a method for using the reaction product H, optionally in combination with at least one of the crosslinking agents (X1) to (X5), as a crosslinking agent, comprising applying the reaction product H to a substrate. The method for using the reaction product H, optionally in combination with at least one of the crosslinking agents (X1) to (X5), as a crosslinking agent comprises: preferably mixing the reaction product H with at least one optional crosslinkable resin and / or optionally with water and / or optionally with at least one organic solvent, homogenizing and applying the homogenized mixture to a substrate. According to a preferred embodiment, the method for using the reaction product H, optionally in combination with at least one of the crosslinking agents (X1) to (X5), as a crosslinking agent comprises: mixing the reaction product H with at least one crosslinkable resin, homogenizing and applying the homogenized mixture to a substrate. If desired, water and / or at least one organic solvent may be included.

[0100] The substrate may preferably be selected from plastics including thermoplastics and thermosetting materials, wood, synthetic wood, ceramics and glass, synthetic wood, leather, textiles, tire cord, rubber goods, paper, cardboard, gypsum, concrete, metals, metallized circuit boards, semiconductor surfaces, displays and packaging for electronic circuits.

[0101] The reaction product H, optionally in combination with at least one of the crosslinking agents (X1) to (X5), can be combined with an aqueous and / or solvent-polymerizable crosslinkable resin (binder resin) having an active hydrogen functional group or an active hydrogen atom as a crosslinking agent, wherein the active hydrogen functional group or the active hydrogen atom is at least one of a hydroxyl group, an acid group, preferably a carboxyl group, a urethane group, an amide group, an imide group, an amino group, an imino group, a thiol group or a phosphine group or an acid group (which can be a carboxylic acid or an acid derived from other organic bonds).

[0102] As crosslinkers comprising product H, which are active already at ambient temperature (20-25° C.) when fully catalyzed, they are particularly suitable for curing coatings on heat-sensitive substrates such as paper, cardboard, textiles, leather, wood, synthetic wood and plastics including composites, thermoplastics and thermosetting materials. Of course, they can also be used as crosslinkers for coating compositions used on substrates such as metals, semiconductor surfaces, ceramics, stone, plaster, glass and concrete, which allow higher curing temperatures. It is also conceivable to use the crosslinkers in combination with the above-mentioned binder resins with a suitable catalyst CB, where curing temperature or energy saving is an issue.

[0103] Suitable catalyst CB is preferably an acid catalyst, particularly selected from organic sulfonic acid, organic phosphonic acid, organic sulfonylimide, organic carboxylic acid and Lewis acid, or a salt or complex of Lewis acid, such as amine salt or ether complex or mineral acid. For example, the boric acid of the monobasic Lewis acid of boron. Useful catalyst CB is p-toluenesulfonic acid (pTSA), dodecylbenzenesulfonic acid (DDBSA), dinonylnaphthalenesulfonic acid (DNNSA) and dinonylnaphthalene disulfonic acid (DNNDSA), which can also be blocked with volatile amine, boric acid used alone or as a mixture with other acid catalysts. Particularly preferred is N-methylsulfonyl p-toluenesulfonamide (MTSI), p-toluenesulfonic acid (pTSA), dodecylbenzenesulfonic acid (DDBSA), dinonylnaphthalenesulfonic acid (DNNSA) and dinonylnaphthalene disulfonic acid (DNNDSA). Of course, it is also possible to use an acid catalyst, such as an acid ester or reaction product of an acid and epoxy functional compound, for example, by releasing the blockage of the acid by heating. Particularly useful catalysts CB are acid catalysts which are usually soluble in alcohol or water, such as p-toluenesulfonic acid or dinonylnaphthalene disulfonic acid or boric acid.

[0104] In particular, the present invention also relates to a coating composition comprising reaction product H and optionally at least one crosslinkable resin (or binder resin) and / or optionally water and / or optionally at least one organic solvent. According to a preferred embodiment, the coating composition comprises reaction product H and at least one crosslinkable resin (or binder resin). Water and / or at least one organic solvent may also be included. The coating composition may preferably be a curable coating composition. Typically, the curable coating composition may be cured under the action of an acidic catalyst CB, which catalyzes the reaction between a crosslinking agent and the crosslinkable resin at ambient temperature or at a higher temperature.

[0105] The crosslinkable resin may preferably be an oligomeric or polymeric material having at least one functional group having an active hydrogen atom, the functional group being selected from the group consisting of a hydroxyl functional group, an acid functional group, a carboxylic acid functional group, an amide functional group, an amino functional group, an imino functional group, an imide functional group, a thiol functional group, a phosphine functional group and a carbamate functional group.

[0106] Suitable active hydrogen-containing materials include, for example, polyfunctional hydroxyl-containing materials such as polyols, hydroxyl-functional acrylic resins having pendant or terminal hydroxyl functional groups, hydroxyl-functional polyester resins having pendant or terminal hydroxyl functional groups, hydroxyl-functional polyurethane prepolymers, products derived from the reaction of epoxy compounds with amines, and mixtures thereof. Acrylic and polyester resins are preferred. Examples of polyfunctional hydroxyl-containing materials include commercially available materials such as 203-1385 alkyd resin (Eastman Chemical Co.); 12035 alkyd resin (Reichhold Chemical Co.), 500 acrylic resin (SC Johnson & Sons, Racine, Wis.); AT-400 acrylic resin (Rohm & Haas, Philadelphia, PA); 3000 and 5776 polyester resins (Cargill, Minneapolis, Minn.); XM-2302 and XM-2306 resins (King Industries, Norwalk, Conn.); 11-1369 Resin (Cook Composites and Polymers, Port Washington, Wis.); 3494 solid hydroxyl terminated polyester resin (Cytec Industries Inc., Woodland Park, NJ); 101 polyester resin (Ruco Polymer, Hicksville, NY); SCX-800-A and SCX-800-B hydroxy-functional solid acrylic resins (SC Johnson & Sons, Racine, Wis.).

[0107] Examples of carboxyl functional resins include Solid carboxyl terminated polyester resin (Cytec Industries Inc., Woodland Park, NJ). Suitable resins containing amino, amido, carbamate or thiol groups (including groups convertible thereto) are generally known to those of ordinary skill in the art and can be prepared by known methods involving copolymerizing appropriately functionalized monomers with comonomers copolymerizable therewith.

[0108] Conventional additives such as organic solvents, coalescing agents, defoamers, leveling agents, fillers, pigments, light stabilizers, antioxidants, colorants, flow control agents, sag control agents, anti-skinning agents, anti-settling agents, adhesion promoters, wetting agents, preservatives, plasticizers, mold release agents and corrosion inhibitors can of course be used in the coating composition comprising the crosslinking agent of the present invention.

[0109] Suitable organic solvents include aromatic hydrocarbons, aliphatic hydrocarbons, halogenated hydrocarbons, ketones, esters, ethers, amides, alcohols, water, compounds having multiple functional groups, such as those having ether and ester groups, and mixtures thereof.

[0110] The coating composition can be preferably prepared by mixing the reaction product H as a crosslinking agent with a crosslinkable resin, wherein the crosslinkable resin is a polymeric resin or an oligomeric resin with active hydrogen atoms, i.e. a hydroxyl, an acid group, preferably at least one of a carboxyl, a carbamate group, an amide group, an imide group, an amino group, an imino group, a thiol group or a phosphine group. The resulting mixture is homogenized and applied to the substrate by spraying, brushing, wire coating, curtain coating, blade coating, roller coating, dip coating, electrophoretic deposition, powder spraying or electrostatic spraying. The method for preparing the coating composition can include mixing water and / or at least one organic solvent.

[0111] The ratio of the solid mass of the crosslinkable resin to the mass of the reaction product H in the coating composition is preferably 99 / 1 to 1 / 99, particularly preferably 95 / 5 to 60 / 40, most preferably 90 / 10 to 70 / 30.

[0112] According to one embodiment of the present invention, the coating composition is an aqueous coating composition, more preferably an aqueous curable coating composition.

[0113] The aqueous curable coating composition can allow the formation of a dispersion, emulsion, inverse emulsion or solution of the ingredients of the curable composition. According to a preferred embodiment, the aqueous curable coating composition comprises the reaction product H and at least one crosslinkable resin (or binder resin) and optional water and / or optional at least one organic solvent. The aqueous curable coating composition can optionally contain a surfactant, an emulsifier, a dispersant, an additive or a mixture thereof.

[0114] The mass fraction of total solids present in the waterborne curable coating composition is generally about 1-60%, preferably about 10-55%, more preferably about 25-50%, based on the total mass of the composition.

[0115] The mass ratio of the active hydrogen-containing material to the crosslinker reaction product H present in the waterborne curable coating composition is generally about 99:1 to about 1:1, preferably 95:5 to 60:40, and more preferably about 90:10 to 70:30.

[0116] The ratio of the mass of surfactant present in the aqueous curable coating composition to the mass of the total active hydrogen-containing material in the composition is generally about 0-10%, preferably about 0.1-5%, and more preferably about 0.5-2.0%.

[0117] The solvent component in the waterborne curable coating composition is a solvent (e.g., water) and an optional cosolvent. Examples of such optional cosolvents are the solvents mentioned above, as long as they are soluble in water or miscible in water in the amount used. Preferred cosolvents for waterborne compositions are alcohols and glycol ethers. The amount of the cosolvent that can be preferably used is expressed as the ratio of the mass of the cosolvent to the mass of the active hydrogen-containing material and the crosslinking agent reaction product H in the waterborne curable composition, which can be about 0-30%, more preferably about 2-25%, and particularly preferably about 5-15%.

[0118] Surfactants, emulsifiers and / or dispersants that can be used in waterborne curable coating compositions are molecules having a hydrophobic portion (Y) and a hydrophilic portion (Z). They can have any molecular structure (Y)-(Z), (Y)-(Z)-(Y), (Z)-(Y)-(Z), etc., where the hyphen represents a chemical bond between portion (Y) and portion (Z). Typically, the hydrophobic portion can be an alkyl or alkylaryl residue, a poly(propyleneoxy) block, a polydimethylsiloxane block, or a fluorocarbon block. The hydrophilic portion of a nonionic surfactant is a water-soluble nonionic block, typically a poly(ethylene-oxy) block or a hydroxylated polymer block. The hydrophilic portion of an anionic surfactant is typically an acid group that is converted to an anionic group by the addition of a base. Typical acid groups are carboxylic acids, sulfonic acids, phosphonic acids, and phosphoric acids that form carboxylate ions, sulfonate ions, phosphonate ions, and phosphate ions. Typical bases for ionizing acids are NaOH, KOH, NH 4 OH and various tertiary amines, such as triethylamine, triisopropylamine, dimethylethanolamine, methyldiethanolamine, etc.

[0119] Anionic surfactants that can be used in water-based curable coating compositions include, for example, salts of fatty acids, preferably sulfuric acid esters or sulfonic acid esters of higher alcohols having 8 to 18 carbon atoms and alkali metal salts thereof, alkylbenzenesulfonates, alkylnaphthalenesulfonates, condensation products of naphthalenesulfonic acid and formalin, dialkyl succinate sulfones, alkyl phosphates, and poly(oxyethylene) sulfates. Particularly preferred are, for example, fatty acid salts such as potassium oleate, and higher alcohol sulfuric acid ester salts such as sodium lauryl sulfate.

[0120] Cationic surfactants that can be used in the aqueous curable coating composition include, for example, alkylamine salts, quaternary ammonium salts, and poly(oxyethylene)alkylamines. Particularly preferred are quaternary ammonium salts such as lauryltrimethylammonium chloride or hexadecyltrimethylammonium chloride.

[0121] Amphoteric surfactants useful in the waterborne curable coating composition include alkyl betaines such as lauryl betaine and stearyl betaine.

[0122] Nonionic surfactants that can be used in the aqueous curable coating composition include, for example, poly(oxyethylene) alkyl ethers, poly(oxyethylene) alkylphenol ethers, fatty acid esters of sugar alcohols or derivatives thereof such as sorbitan (a mixture of dehydration products of sorbitol), polyoxyethylene sorbitan fatty acid esters, for example, polyoxyethylene sorbitan monolaurate or monostearate, polyoxyethylene acrylates, (oxyethylene-oxypropylene) block copolymers and monoglycerol fatty acid esters.

[0123] Particularly preferred active hydrogen-containing materials for use in waterborne curable coating compositions are hydroxyl-functional acrylic resins having an acid value of 3-20 mg / g and a hydroxyl value of 20-150 mg / g and a solids mass fraction of 40-55%, such as 1024 lotion (DOW), SM 6826W / 43WA (Allnex).

[0124] Particularly preferred resins for waterborne curable coating compositions are hydroxyl-functional acrylic resins having sulfonic acid groups incorporated into the polymer. Specifically, the hydroxyl-functional acrylic resins having pendant sulfonic acid groups incorporated into the polymer may be those described in US 2014 / 0243469 A1, and each of which is incorporated herein by reference in its entirety.

[0125] According to one embodiment of the present invention, the coating composition is a solvent-borne coating composition, more preferably a solvent-borne curable coating composition.

[0126] A preferred variant is a coating composition which is a solvent-based curable coating composition comprising a crosslinkable resin which is an oligomeric or polymeric material whose functional groups are hydroxyl groups, and the polymeric or oligomeric material is selected from acrylic resins, polyester resins, alkyd resins, polyurethane resins, epoxy resins, vinyl resins, polyether polyols, characterized in that the polymeric or oligomeric material has a hydroxyl value of 5-300 mg / g.

[0127] The coating compositions of the present invention can be preferably used as coatings for the general field of coatings, such as original equipment manufacturing (OEM) including automotive coatings, general industrial coatings including industrial maintenance coatings, architectural coatings, agricultural and construction equipment coatings (ACE), powder coatings, coil coatings, can coatings, wood coatings and low temperature curing automotive refinishing paints. They can be used as coatings for wires, electrical appliances, automotive parts, furniture, pipes, machinery, etc. They can also be used in electronic applications, including coatings for metallized circuit boards, semiconductor surfaces, displays and electronic circuit packaging.

[0128] The coating compositions can be applied by any known technique, such as spraying, dipping, brushing, wire coating, curtain coating and knife coating. If formulated as a solid, they can also be used as crosslinking agents in powder coating compositions and can be applied by conventional methods such as electrostatic spraying or powder spraying.

[0129] All the above-mentioned embodiments can be implemented individually or can be reasonably combined.

[0130] The present invention is now further described in more detail in the following examples, which are in no way intended to limit the invention or its application. Example

[0131] All concentrations (strengths) and ratios expressed in "%" are mass fractions (ratio of the mass mB of a particular substance B divided by the mass m of the mixture (in the case of concentrations) or by the mass mD of a second substance D (in the case of ratios). According to DIN EN ISO 3682 (DIN 53 402), the acid number is defined as the ratio of the mass mKOH of potassium hydroxide required to neutralize the sample to be tested to the mass mB of the sample or the mass of the solids in the sample (in the case of solutions or dispersions); the usual unit is "mg / g". According to DIN EN ISO 4629 (DIN 53 240), the hydroxyl value is defined as the ratio of the mass mKOH of potassium hydroxide having the same hydroxyl number as the sample to the mass mB of the sample (the mass of the solid in the solution or dispersion sample); the commonly used unit is "mg / g". The dynamic viscosity is measured with the Gardner-Holt scale and converted into SI units (mPa.s). GO represents glyoxal and EU represents ethylene urea. n is the symbol of the physical quantity "amount of substance" having the SI unit "mole". M is the symbol of the physical quantity "molar mass" having the SI unit "kilogram / mole".

[0132] C-NMR analysis was performed using a Bruker-Oxford 13Avance II 400 NMR spectrometer with a 100 mm probe. The samples were prepared by diluting the reaction product with approximately the same mass of dimethyl sulfoxide-d6.

[0133] The molar mass of the reaction product was measured by HPSEC or gel permeation chromatography using tetrahydrofuran or dimethylacetamide as solvent, with a sample concentration of 1 g / 100 ml, a flow rate of 1.0 ml / min, a column temperature of 65 / C, and a column packed with a set of cross-linked polystyrene beads with a particle size of 10 μm and a pore size of 10 nm (3x) for refractometry detection, providing a measurement range of 100 g / mol to 50 kg / mol for calibration with polystyrene standards. Data collection and analysis were performed using software provided by Agilent Technologies.

[0134] Example 1 : Glyoxal resin containing 2-imidazolidinone and 2-methyl-propane-1,3-diol.

[0135] (the molar ratio of GO (glyoxal):EU (ethylene urea):polyol=1.16:1.00:0.46), and the polyol is 2-methyl-1,3-propanediol (MP diol).

[0136] The resin of the present invention is prepared by the following steps:

[0137] 169.7 parts (1.17 moles) of aqueous glyoxal solution (glyoxal, 40% solute mass fraction) were added to the reaction vessel under nitrogen purge, and the pH was adjusted to 6.2 with aqueous sodium bicarbonate solution (8% solid mass fraction). 185.5 parts (1.01 moles) of ethylene urea (MW 86, 2-imidazolidinone solution, 46.9% solute mass fraction) were added at ambient temperature within 15-30 minutes. The reaction mixture was heated to 25°C and a mild exotherm to 35-40°C was observed. The temperature was raised to 45-50°C and maintained for one and a half hours. At the end of this time, 41.75 parts (0.46 moles) of 2-methyl-1,3-propanediol (MP diol) were added to the reaction vessel. The reaction mixture was maintained at 50°C for one and a half hours. At the end of the hold, excess water was slowly removed at reaction temperature and reduced pressure (600 mmHg plummeted to 220 mmHg) until a solid mass fraction of about 61% was reached. The heat was turned off and the reaction mixture was cooled to ambient temperature. 320 g of a straw yellow solution of the product was separated. A product having a dynamic viscosity of about 627 mPa.s and a solid mass fraction of 61.50% was obtained.

[0138] The amount of MP diol reacted and the molar mass of the resulting straw yellow crosslinker solution were determined by C-13 NMR to be (n(-diol) / n(EU)=0.15 mol / mol; "EU" represents ethylene urea; the amount of unreacted MP diol was (n(-diol) / n(EU)=0.34 mol / mol; the molar mass was determined by HPSEC (Mn=1572 g / mol, Mn represents the number average molar mass) analysis.

[0139] The product of this example remained fluid for about 15 days or more at ambient storage temperature and remained fluid for less than 8 days when stored at 50°C.

[0140] When evaluated in ambient and low-bake thermal cure waterborne surface coating applications, the product of Example 1 produced coating films having good appearance, satisfactory resistance properties, and excellent formulation stability.

[0141] Example 2 : Glyoxal resin containing 2-imidazolidinone and 2-methyl-propane-1,3-diol.

[0142] (GO:EU:MP diol molar ratio = 1.17:1.0:0.47)

[0143] The resin of the present invention is prepared by the following steps:

[0144] 616.2 parts (4.25 moles) of aqueous glyoxal (glyoxal, 40% solute mass fraction) were added to the reaction vessel under nitrogen purge and the pH was adjusted to 6.2 with aqueous sodium bicarbonate (8% solid mass fraction). 732.9 parts (3.62 moles) of ethylene urea (MW 86, 2-imidazolidinone solution, 42.5% solute mass fraction) were added at ambient temperature over 15-30 minutes. The reaction mixture was heated to 25°C and a mild exotherm to 35-40°C was observed. The temperature was raised to 45-50°C and maintained for one hour. At the end of this time, 152.14 parts (1.69 moles) of 2-methyl-1,3-propanediol were added to the reaction vessel, followed by 3.43 parts (0.0179 moles) of citric acid. The pH was measured to be in the range of 3.1-3.6. The reaction mixture was maintained at 50°C for 4 hours with stirring. At the end of 4 hours, the pH was adjusted to about 6.0-6.5 using aqueous sodium hydroxide solution (25% solids mass fraction). The heat was turned off, the reaction mixture was allowed to cool to ambient temperature and filtered. 1520 grams of a straw yellow solution of the product were separated. A product with a dynamic viscosity of about 100 mPa.s and a solids mass fraction of 48.0% was obtained.

[0145] The amount of MP diol reacted and the molar mass of the resulting yellow crosslinker solution were determined by C-13 NMR to be (n(-diol) / n(EU)=0.27 mol / mol; "EU" represents ethylene urea; the amount of unreacted MP diol was (n(-diol) / n(EU)=0.22 mol / mol; the molar mass was determined by HPSEC (Mn=1377 g / mol, Mn represents the number average molar mass) analysis.

[0146] The product of this example remained fluid for about 15 days or more at ambient storage temperature and remained fluid for more than ten days when stored at 50°C.

[0147] The product of Example 2 resulted in coating films having good appearance, satisfactory resistance properties and excellent formulation stability when evaluated in ambient and heat-curing waterborne surface coating applications. In addition, it has been observed that the use of the product of Example 2 provides better resistance properties to the color stability of the heat-aged films of the resulting coatings than the use of the product of Example 1. This example shows that higher conversions of bound polyols are obtained when an organic acid catalyst is used.

[0148] Example 3 : Glyoxal resin with 2-imidazolidinone and 2-methyl-propane-1,3-diol.

[0149] (GO:EU:MP diol molar ratio = 1.18:1.0:0.40)

[0150] The resin of the present invention is prepared by the following steps:

[0151] 171.0 parts (1.18 moles) of aqueous glyoxal solution (glyoxal, 40% solute mass fraction) were added to the reaction vessel under nitrogen purge and the pH was adjusted to 5.9 with aqueous sodium bicarbonate solution (8% solid mass fraction). 211.5 parts (1.00 moles) of ethylene urea (MW 86, 2-imidazolidinone solution, 41.0% solute mass fraction) were added at ambient temperature over 15-30 minutes. The reaction mixture was heated to 25°C and a mild exotherm to 35-40°C was observed. The temperature was raised to 45-50°C and once 50°C was reached, water was removed under vacuum (from 600 mmHg to 100 mmHg) at the reaction temperature (50°C) to a final mass fraction of about 64% solids. After the water was removed, water equivalent to the mass of water removed in the previous step was added to return the reaction to its initial mass fraction. At the end of this time, 36.2 parts (0.40 mol) of MP diol were added to the reaction vessel, followed by 1.1 parts (0.0056 mol) of citric acid. The pH was found to be in the range of 3.1-3.6. The reaction mixture was kept at 50° C. for 4 hours with stirring. At the end of 4 hours, the pH was adjusted to about 6.0-6.5 using an aqueous sodium hydroxide solution (25% by mass). The heat was turned off, the reaction mixture was allowed to cool to ambient temperature and filtered. 450 g of a straw yellow solution of the product were separated. A product having a dynamic viscosity of about 100 mPa.s and a solid mass fraction of 43.2% was obtained.

[0152] The amount of reacted MP diol in the resulting yellow crosslinker solution (about 450 g) was determined by C-13 NMR to be (n(-diol) / n(EU)=0.20 mol / mol; "EU" represents ethylene urea; the amount of unreacted MP diol was (n(-diol) / n(EU)=0.17 mol / mol.

[0153] Under ambient storage conditions, the sample remained fluid after six months.

[0154] Example 4 : Glyoxal resin with 2-imidazolidinone and 2-methyl-propane-1,3-diol.

[0155] (GO:EU:MP diol=1.19:1.0:0.40)

[0156] The resin of the present invention is prepared by the following steps:

[0157] 8585.6 parts (59.2 moles) of aqueous glyoxal solution (glyoxal, 40% solute mass fraction) were added to the reaction vessel under nitrogen purge, and the pH was adjusted to 6.2 with aqueous sodium bicarbonate solution (8% solid mass fraction). 9000.8 parts (49.8 moles) of ethylene urea (MW 86, 2-imidazolidinone solution, 47.7% solute mass fraction) were added at ambient temperature within 15-30 minutes. The reaction mixture was heated to 25°C and a mild exotherm to 35-40°C was observed. The temperature was raised to 45-50°C and maintained for about 1 hour. At the end of the holding period, 1808.2 parts (20.06 moles) of MP diol were added to the reaction vessel, followed by 48.2 parts (0.251 moles) of citric acid. The pH was measured to be in the range of 3.1-3.6. The reaction mixture was maintained at 50°C for 4 hours under stirring. At the end of 4 hours, the pH was adjusted to about 6.0-6.5 using aqueous sodium hydroxide solution (25% by mass). The heat was turned off, the reaction mixture was allowed to cool to ambient temperature and filtered. A straw yellow solution of the product was isolated, with a dynamic viscosity of about 100 mPa.s, and a solid mass fraction of 42.0% was obtained.

[0158] The amount of reacted MP diol in the resulting yellow crosslinker solution (about 19,800 g) was determined by C-13 NMR to be (n(-diol) / n(EU)=0.22 mol / mol; "EU" represents ethylene urea; the amount of unreacted MP diol was (n(-diol) / n(EU)=0.15 mol / mol.

[0159] Example 5 : Glyoxal resin with 2-imidazolidinone and 2-ethyl-2-hydroxymethyl-1,3-propanediol.

[0160] (GO:EU:2-ethyl-2-hydroxymethyl-1,3-propanediol=1.18:1.0:0.17)

[0161] This is an example using triol 2-ethyl-2-hydroxymethyl-1,3-propanediol (TMP) as the polyol.

[0162] The resin of the present invention is prepared by the following steps:

[0163] 38.8 parts (0.267 moles) of aqueous glyoxal solution (glyoxal, 40% solute mass fraction) were added to the reaction vessel under nitrogen purge, and the pH was adjusted to 6.2 with aqueous sodium bicarbonate solution (8% solid mass fraction). 41.0 parts (0.226 moles) of ethylene urea (MW 86, 2-imidazolidinone solution, 47.5% solute mass fraction) were added at ambient temperature within 15-30 minutes. The reaction mixture was heated to 25°C and a mild exotherm to 35-40°C was observed. The temperature was raised to 45-50°C and maintained for about 1 hour. At the end of the holding period, 5.0 parts (0.0375 moles) of TMP were added to the reaction vessel, followed by 0.22 parts (0.001146 moles) of citric acid. The pH was measured to be in the range of 3.1-3.6. The reaction mixture was kept at 50°C for 4 hours under stirring. At the end of 4 hours, the pH was adjusted to about 6.0-6.5 using aqueous sodium hydroxide solution (25% by mass). The heat was turned off, the reaction mixture was allowed to cool to ambient temperature and filtered. A straw yellow solution of the product was isolated, with a dynamic viscosity of about 300 mPa.s, and a solid mass fraction of 48.3% was obtained.

[0164] The amount of reacted TMP in the resulting yellow crosslinker solution (about 86 g) was determined by C-13 NMR to be (n(-diol) / n(EU)=0.08 mol / mol; "EU" represents ethylene urea; the amount of unreacted TMP was (n(-diol) / n(EU)=0.07 mol / mol.

[0165] Example 6 : Glyoxal resin with 2-imidazolidinone and 1,6-hexanediol.

[0166] (GO:EU:hexanediol=1.18:1.0:0.39)

[0167] This is an example using a diol such as hexylene glycol (HD).

[0168] The resin of the present invention is prepared by the following steps:

[0169] 172.55 parts (1.19 moles) of aqueous glyoxal solution (glyoxal, 40% solute mass fraction) were added to the reaction vessel under nitrogen purge and the pH was adjusted to 6.2 with aqueous sodium bicarbonate solution (8% solid mass fraction). 212.32 parts (1.01 moles) of ethylene urea (MW 86, 2-imidazolidinone solution, 41.0% solute mass fraction) were added at ambient temperature over 15-30 minutes. The reaction mixture was heated to 25°C and a mild exotherm to 35-40°C was observed. The temperature was raised to 45-50°C and once 50°C was reached, water was removed under vacuum (from 600 mmHg to 220 mmHg) at the reaction temperature (50°C) to a final mass fraction of about 64% solids. After the water was removed, water equivalent to the mass of water removed in the previous step was added to return the reaction to its initial mass fraction. At the end of this time, 47.0 parts (0.40 mole) of 1,6-hexanediol were added to the reaction vessel, followed by 1.04 parts (0.0054 mole) of citric acid. The pH was measured to be in the range of 3.1-3.6. The reaction mixture was maintained at 50°C for 4 hours with stirring. At the end of 4 hours, the pH was adjusted to about 6.0-6.5 using aqueous sodium hydroxide solution (25% by mass). The heat was turned off, the reaction mixture was allowed to cool to ambient temperature and filtered. A straw yellow solution of non-alkylated product was separated, having a solids mass fraction of 43.7%.

[0170] The product of Example 6 remained fluid for less than 8 days.

[0171] Example 7 : Glyoxal resin with 2-imidazolidinone and 2-methyl-1,3-propanediol.

[0172] (GO:EU:MP diol=1.18:1.0:0.40)

[0173] This example illustrates the use of succinic acid in the process.

[0174] The resin of the present invention is prepared by the following steps:

[0175] 350 parts (2.41 moles) of aqueous glyoxal solution (glyoxal, 40% solute mass fraction) were added to the reaction vessel under nitrogen purge and the pH was adjusted to 6.2 with aqueous sodium bicarbonate solution (8% solid mass fraction). 372 parts (2.05 moles) of ethylene urea (MW 86, 2-imidazolidinone solution, 47.5% solute mass fraction) were added at ambient temperature over 15-30 minutes. The reaction mixture was heated to 25°C and a mild exotherm to 35-40°C was observed. The temperature was raised to 45-50°C and once 50°C was reached, water was removed under vacuum (from 600 mmHg to 140 mmHg) at the reaction temperature (50°C) to a final mass fraction of about 55% solids. After the water was removed, water equivalent to the mass of water removed in the previous step was added to return the reaction to its initial mass fraction. At the end of this time, 74 parts (0.82 mol) of MP diol were added to the reaction vessel, followed by 3.89 parts (0.0330 mol) of succinic acid. The pH was measured to be in the range of 3.1-3.6. The reaction mixture was kept at 50° C. for 4 hours with stirring. At the end of 4 hours, the pH was adjusted to about 6.0-6.5 using an aqueous sodium hydroxide solution (25% by mass). The heat was turned off, the reaction mixture was allowed to cool to ambient temperature and filtered. A straw yellow solution of the product was separated, the dynamic viscosity of which was about 300 mPa.s, and a solid mass fraction of 41.0% was obtained.

[0176] The amount of reacted MP diol in the resulting yellow crosslinker solution (about 810 g) was determined by C-13 NMR to be (n(-diol) / n(EU)=0.21 mol / mol; "EU" represents ethylene urea; the amount of unreacted MP diol was (n(-diol) / n(EU)=0.20 mol / mol.

[0177] The product of this example remains fluid for about 9 months or more at ambient storage temperature.

[0178] When evaluated in ambient and heat-curing waterborne surface coating applications, the product resulted in coating films with good appearance and satisfactory resistance properties.

[0179] Example 8 : Glyoxal resin containing 2-imidazolidinone and 2-methyl-1,3-propanediol. (GO:EU:MPdiol=1.15:1.0:0.39)

[0180] This example illustrates the use of lactic acid in the method.

[0181] The resin of the present invention is prepared by the following steps:

[0182] 165.9 parts (1.14 moles) of aqueous glyoxal solution (glyoxal, 40% solute mass fraction) were added to the reaction vessel under nitrogen purge and the pH was adjusted to 6.2 with aqueous sodium bicarbonate solution (8% solid mass fraction). 179.9 parts (0.99 moles) of ethylene urea (MW 86, 2-imidazolidinone solution, 47.5% solute mass fraction) were added at ambient temperature over 15-30 minutes. The reaction mixture was heated to 25°C and a mild exotherm to 35-40°C was observed. The temperature was raised to 45-50°C and once 50°C was reached, water was removed under vacuum (from 600 mmHg to 140 mmHg) at the reaction temperature (50°C) to a final mass fraction of about 56% solids. After the water was removed, water equivalent to the mass of water removed in the previous step was added to return the reaction to its initial mass fraction. At the end of this time, 35.1 parts (0.39 mol) of MP diol were added to the reaction vessel, followed by 1.46 parts (0.0162 mol) of lactic acid. The pH was found to be in the range of 3.1-3.6. The reaction mixture was kept at 50° C. for 4 hours with stirring. At the end of 4 hours, the pH was adjusted to about 6.0-6.5 using an aqueous solution of sodium hydroxide (25% by mass). The heat was turned off, the reaction mixture was allowed to cool to ambient temperature and filtered. A straw yellow solution of the unalkylated product was separated, the dynamic viscosity of which was about 627 mPa.s, and a solid mass fraction of 45.2% was obtained.

[0183] The amount of reacted MP diol in the resulting yellow crosslinker solution (about 388 g) was determined by C-13 NMR to be (n(-diol) / n(EU)=0.28 mol / mol; "EU" represents ethylene urea; the amount of unreacted MP diol was (n(-diol) / n(EU)=0.13 mol / mol.

[0184] When evaluated in ambient and heat cure waterborne surface coating applications, the product resulted in coating films with good appearance and satisfactory resistance properties.

[0185] Example 9 : Glyoxal resin with 2-imidazolidinone and 2-methyl-1,3-propanediol.

[0186] (GO:EU:MP diol=1.18:1.0:0.40), and inorganic acid sulfuric acid was used as the acid catalyst.

[0187] The resin of the present invention is prepared by the following steps:

[0188] 190.3 parts (1.31 moles) of aqueous glyoxal solution (glyoxal, 40% solute mass fraction) were added to the reaction vessel under nitrogen purge, and the pH was adjusted to 6.2 with aqueous sodium bicarbonate solution (8% solid mass fraction). 200.7 parts (1.11 moles) of ethylene urea (MW 86, 2-imidazolidinone solution, 47.7% solute mass fraction) were added at ambient temperature within 15-30 minutes. The reaction mixture was heated to 25°C and a mild exotherm to 35-40°C was observed. The temperature was raised to 45-50°C and maintained for 1 hour. At the end of this holding time, 40.2 parts (0.45 moles) of MP diol were added to the reaction vessel, followed by 0.2 parts (0.0018 moles) of sulfuric acid. The pH was measured to be in the range of 3.0-3.6. The reaction mixture was kept at 50°C for 4 hours under stirring. At the end of 4 hours, the pH was adjusted to about 6.0-6.5 using aqueous sodium hydroxide solution (25% by mass). The heat was turned off and the reaction mixture was allowed to cool to ambient temperature and filtered. A straw yellow solution of the product was isolated.

[0189] The product of this example turned into a solid gel and did not flow within four days at ambient storage temperature. It was noted that although showing satisfactory performance, the resulting product was more viscous due to the use of a mineral acid.

[0190] Example 10 : Glyoxal resin with 2-imidazolidinone and 2-methyl-propane-1,3-diol.

[0191] (GO:EU:MP diol=1.18:1.00:0.40)

[0192] 800.9 parts (5.52 moles) of aqueous glyoxal solution (glyoxal, 40% solute mass fraction) were added to the reaction vessel under nitrogen purge, and the pH was adjusted to 5.8 with aqueous sodium bicarbonate solution (8% solid mass fraction). 851.4 parts (4.70 moles) of ethylene urea (MW 86, 2-imidazolidinone solution, 47.5% solute mass fraction) were added at ambient temperature over 15-30 minutes. The reaction mixture was heated to 25°C and a mild exotherm to 35-40°C was observed. The temperature was raised to 45-50°C and maintained for 1 hour. At the end of this time, 170.1 parts (1.89 moles) of 2-methyl-1,3-propanediol were added to the reaction vessel, followed by 4.49 parts (0.0234 moles) of citric acid. The pH was measured to be in the range of 3.1-3.6. The reaction mixture was maintained at 50°C for 4 hours under stirring. At the end of 4 hours, the pH was adjusted to about 6.0-6.5 using aqueous sodium hydroxide solution (25% solids mass fraction). The heat was turned off, the reaction mixture was allowed to cool to ambient temperature and filtered. 1850 grams of a straw yellow solution of the product were separated. A product with a dynamic viscosity of about 140 mPa.s and a solids mass fraction of 43.8% was obtained.

[0193] The amount of reacted MP diol in the resulting yellow crosslinker solution was determined by C-13 NMR to be (n(-diol) / n(EU)=0.22 mol / mol; "EU" represents ethylene urea; the amount of unreacted MP diol was (n(-diol) / n(EU)=0.16 mol / mol.

[0194] When evaluated in ambient and heat cure waterborne surface coating applications, this product resulted in coating films with good appearance and satisfactory resistance properties.

[0195] Embodiment 11 : Glyoxal resin with 2-imidazolidinone and 2-methyl-propane-1,3-diol.

[0196] (GO:EU:MP diol=1.18:1.0:0.40MPD)

[0197] The resin of the present invention is prepared by the following steps:

[0198] 690 parts (4.76 moles) of aqueous glyoxal solution (glyoxal, 40% solute mass fraction) were added to the reaction vessel under nitrogen purge and the pH was adjusted to 5.9 with aqueous sodium bicarbonate solution (8% solid mass fraction). 730 parts (4.03 moles) of ethylene urea (MW 86, 2-imidazolidinone solution, 47.5% solute mass fraction) were added at ambient temperature over 15-30 minutes. The reaction mixture was heated to 25°C and a mild exotherm to 35-40°C was observed. The temperature was raised to 45-50°C and once 50°C was reached, water was removed under vacuum (from 600 mmHg to 100 mmHg) at the reaction temperature (50°C) to a final mass fraction of about 55% solids. After the water was removed, water equivalent to the mass of water removed in the previous step was added to return the reaction to its initial mass fraction. At the end of this time, 145 parts (1.61 mol) of MP diol were added to the reaction vessel, followed by 4.0 parts (0.0208 mol) of citric acid. The pH was found to be in the range of 3.1-3.6. The reaction mixture was kept at 50° C. for three and a half hours with stirring. At the end of three and a half hours, the pH was adjusted to about 6.0-6.5 using an aqueous solution of sodium hydroxide (25% by mass). The heat was turned off, the reaction mixture was allowed to cool to ambient temperature and filtered. A straw yellow solution of the product was separated, the dynamic viscosity of which was about 100 mPa.s, and a solid mass fraction of 43.3% was obtained.

[0199] The amount of reacted MP diol in the resulting yellow crosslinker solution (about 1580 g) was determined by C-13 NMR to be (n(-diol) / n(EU)=0.25 mol / mol; "EU" represents ethylene urea; the amount of unreacted MP diol was (n(-diol) / n(EU)=0.18 mol / mol.

[0200] When evaluated in ambient and heat-curing waterborne surface coating applications, the product resulted in coating films with good appearance and satisfactory resistance properties.

[0201] Example 12 : Glyoxal resin with 2-imidazolidinone and 2-methyl-propane-1,3-diol.

[0202] (GO:EU:MP diol=1.18:1.0:0.40MPD)

[0203] The resin of the present invention is prepared by the following steps:

[0204] 1983.1 parts (13.67 moles) of aqueous glyoxal solution (glyoxal, 40% solute mass fraction) were added to the reaction vessel under nitrogen purge and the pH was adjusted to 5.9 with aqueous sodium bicarbonate solution (8% solid mass fraction). 2103.9 parts (11.61 moles) of ethylene urea (MW 86, 2-imidazolidinone solution, 47.5% solute mass fraction) were added at ambient temperature over 15-30 minutes. The reaction mixture was heated to 25°C and a mild exotherm to 35-40°C was observed. The temperature was raised to 45-50°C and once 50°C was reached, water was removed under vacuum (from 600 mmHg to 100 mmHg) at the reaction temperature (50°C) to a final mass fraction of about 55% solids. After the water was removed, water equivalent to the mass of water removed in the previous step was added to return the reaction to its initial mass fraction. At the end of this time, 420.1 parts (4.66 mol) of MP diol were added to the reaction vessel, followed by 11.25 parts (0.0586 mol) of citric acid. The pH was found to be in the range of 3.1-3.6. The reaction mixture was kept at 50° C. for three and a half hours with stirring. At the end of three and a half hours, the pH was adjusted to about 6.0-6.5 using an aqueous sodium hydroxide solution (25% by mass). The heat was turned off, the reaction mixture was allowed to cool to ambient temperature and filtered. A straw yellow solution of the product was separated, the dynamic viscosity of which was about 100 mPa.s, and a solid mass fraction of 41.4% was obtained.

[0205] The amount of reacted MP diol in the resulting yellow crosslinker solution (about 4580 g) was determined by C-13 NMR to be (n(-diol) / n(EU)=0.24 mol / mol; "EU" represents ethylene urea; the amount of unreacted MP diol was (n(-diol) / n(EU)=0.16 mol / mol.

[0206] Embodiment 13 : Glyoxal resin with 2-imidazolidinone and 2-methyl-propane-1,3-diol.

[0207] (GO:EU:MP diol=1.19:1.0:0.41)

[0208] The resin of the present invention is prepared by the following steps:

[0209] 8583 parts (59.15 moles) of aqueous glyoxal solution (glyoxal, 40% solute mass fraction) were added to the reaction vessel under nitrogen purge, and the pH was adjusted to 5.8 with aqueous sodium bicarbonate solution (8% solid mass fraction). 9001 parts (49.8 moles) of ethylene urea (MW 86, 2-imidazolidinone solution, 47.7% solute mass fraction) were added at ambient temperature within 15-30 minutes. The reaction mixture was heated to 25°C and a mild exotherm to 35-40°C was observed. The temperature was raised to 45-50°C and maintained for 1 hour. At the end of this holding time, 1821 parts (20.21 moles) of MP diol were added to the reaction vessel, followed by 48 parts (0.2501 moles) of citric acid. The pH was measured to be in the range of 3.1-3.6. The reaction mixture was maintained at 50°C for 4 hours under stirring. At the end of 4 hours, the pH was adjusted to about 6.0-6.5 using aqueous sodium hydroxide solution (25% by mass). The heat was turned off, the reaction mixture was allowed to cool to ambient temperature and filtered. A straw yellow solution of the product was isolated, with a dynamic viscosity of about 133 mPa.s, and a solid mass fraction of 42.1% was obtained.

[0210] The amount of reacted MP diol in the resulting yellow crosslinker solution (about 19,800 g) was determined by C-13 NMR to be (n(-diol) / n(EU)=0.23 mol / mol; "EU" represents ethylene urea; the amount of unreacted MP diol was (n(-diol) / n(EU)=0.17 mol / mol.

[0211] When evaluated in high temperature baking applications for industrial waterborne surface coating applications, the product resulted in coating films with good appearance and satisfactory resistance properties.

[0212] Embodiment 14 : Methylated glyoxal resin with 2-imidazolidinone and 2-methyl-1,3-propanediol.

[0213] (GO:EU:MP diol=1.18:1.0:0.40)

[0214] The resin of the present invention is further reacted with a primary hydroxy monofunctional alcohol methanol and illustrates the optional preparation of the etherified resin of the present invention.

[0215] At ambient temperature, 351.7 parts of the product from Example 3 (EuGo-MP diol, 43.2% by mass of solute) are added to a reaction vessel and 126.4 parts (3.94 moles) of methanol (MW=32.04) are added. The temperature of the mixture is then raised to 45-50°C, once 50°C is reached, 5.21 parts (0.0207 moles) of nitric acid (MW=63.01, 25.0% by mass) are added and the pH is measured at 2.0-2.3. The reaction mixture is kept at 50°C for 4 hours under stirring. At the end of 4 hours, the pH is adjusted to about 6.0-6.5 using an aqueous sodium hydroxide solution (25% by mass). Approximately 485 g of a straw yellow solution of the alkylated product are separated.

[0216] The amount of MP diol reacted in the resulting yellow crosslinker solution was determined by C-13 NMR to be (n(-diol) / n(EU)=0.14 mol / mol; "EU" represents ethylene urea; the amount of unreacted MP diol was (n(-diol) / n(EU)=0.25 mol / mol. The degree of etherification (or the amount of methanol reacted) of the product of Example 14 was determined by C-13 NMR to be (n(-methoxy) / n(EU)=1.36 mol / mol.

[0217] Embodiment 15 : Glyoxal resin with 2-imidazolidinone and 2-methyl-propane-1,3-diol.

[0218] (GO:EU:MP diol=1.18:1.0:0.40)

[0219] The resin of the present invention is prepared by the following steps:

[0220] 801.1 parts (5.52 moles) of aqueous glyoxal (glyoxal, 40% solute mass fraction) were added to the reaction vessel under nitrogen purge and the pH was adjusted to 5.9 with aqueous sodium bicarbonate (8% solid mass fraction). 847.4 parts (4.67 moles) of ethylene urea (MW 86, 2-imidazolidinone solution, 47.5% solute mass fraction) were added at ambient temperature over 15-30 minutes. The reaction mixture was heated to 25°C and a mild exotherm to 35-40°C was observed. The temperature was raised to 45-50°C and once 50°C was reached, water was removed under vacuum (from 600 mmHg to 100 mmHg) at the reaction temperature (50°C) to a final mass fraction of about 55% solids. After the water was removed, 170.6 parts (1.89 moles) of MP diol were added to the reaction vessel followed by 4.6 parts (0.0242 moles) of citric acid. The pH was found to be in the range of 3.1-3.6. The reaction mixture was maintained at 50°C for 2 hours with stirring. At the end of 2 hours, the pH was adjusted to about 6.0-6.5 using aqueous sodium hydroxide solution (25% by mass). The heat was turned off, the reaction mixture was allowed to cool to ambient temperature and filtered.

[0221] After filtering, the product H of this experiment was taken out and diluted with various solvents. For the first dilution, called H1, 231.2 parts of H (EuGO-MP diol) were taken out and diluted with 63.7 parts of water to produce a diluted product with a mass fraction of solute of 40.2%. For the second dilution, called H2, 202.8 parts of H (EuGO-MP diol) were taken out and diluted with 55.8 parts of 1-methoxy-2-propanol to produce a diluted product with a mass fraction of solute of 40.6%. Therefore, the diluted product can be obtained in water or solvent.

[0222] Comparative Examples Not According to the Invention : Non-alkylated 2-imidazolidinone-glyoxal resin.

[0223] (GO:EU=1.18:1.0)

[0224] A resin that does not use a polyol in the process is prepared by the following procedure:

[0225] 290 parts (2 moles) of aqueous glyoxal solution (glyoxal, 40% solute mass fraction) were added to the reaction vessel under nitrogen purge, and the pH was adjusted to 6.2 with aqueous sodium bicarbonate solution (10% solid mass fraction). 161.5 parts (1.7 moles) of ethylene urea hemihydrate (MW 95, 2-imidazolidinone, solid) were added at ambient temperature over 45-60 minutes. The reaction mixture was heated to 25°C, and a mild exotherm to 35-40°C was observed, with an increase in pH of about 0.55 to 1.5 pH units. The temperature was raised to 42-48°C and maintained for 1 hour. The heat was turned off, and the reaction mixture was cooled to ambient temperature for 3-4 hours. A straw yellow solution of non-alkylated product was separated, with a dynamic viscosity of about 570 mPa.s, and a solid mass fraction of 56.5% was obtained. The product was further diluted with 115 g of deionized water to obtain a non-alkylated product having a solid mass fraction of 45% and a dynamic viscosity of about 125 mPa.s.

[0226] The product of this example remained fluid at 50°C for less than 8 days.

[0227] Example C1 : The coating composition was prepared using the crosslinking agent composition of Example 1 and Example 2.

[0228] The coating composition was prepared by using the ingredients listed in Table 1 below. Acrylic emulsion EMP 9524 (corresponding to a hydroxy-functional acrylic resin having sulfonic acid groups incorporated into the polymer, examples of such resins being described in US 2014 / 0243469A1) was added to a container equipped with a suitable mixing device, followed by the addition of solvent and the required amount of catalyst ("pTSA" p-toluenesulfonic acid, dissolved in water). The crosslinkers of Examples 1 and 2 (formaldehyde-free crosslinkers) were added and stirred together with the rheology modifier and additional solvent (if necessary) to provide a coating formulation having a solid mass fraction of 40% and a total mass ratio of binder to crosslinker of 80 / 20.

[0229] Table 1: Coating composition

[0230]

[0231] The films were prepared by applying the coating compositions of Examples C1.1 and C1.2 onto the surfaces of 101.6 mm x 152.4 mm (4" x 6") clean glass plates and white base coated B1000 steel plates and using a wire wound coating rod #50 to spread the applied formulation to obtain a uniform film. The coated panels were then flashed at room temperature for 24 hours or at 65°C for 15 minutes under ambient conditions (20-25°C) and the film properties were measured after twenty-four hours. The film appearance was judged visually, where the coating films indicated by "poor" had an irregular surface and the coating films indicated by "good" had a smooth, transparent surface without wrinkles. A BYK Gardner Pendulum hardness tester was used. Hardness (measured according to ASTM D 4366, equivalent to DIN EN ISO 1522) measures film hardness. Heat aging yellowing Δb* is defined as the b* value before and after heating a coated white panel at 80°C for 2 hours and measuring it with a BYK Gardner spectro guide.

[0232] The results summarized in Table 2 were obtained when curing at ambient temperature (23°C).

[0233] Table 2: Coating properties

[0234] Coating preparation C1.1 C1.2 Dry film thickness, mil 2.4 2.4 Film appearance good good According to Konig's hardness 106 102 Thermal aging yellowing Δb* 2.43 1.7

[0235] Evaluation of the crosslinkable compositions of Examples 1 and 2 in aqueous coating applications of coating compositions C1.1 and C1.2 showed that these new products provided acceptable coating properties. In addition, the product of Example 2 made with citric acid achieved improved color stability of heat aged films with a Δb* (Δb) value of 1.7.

[0236] Example C2 : A coating composition was prepared using the crosslinker composition of Example 2.

[0237] Coating formulations can also be prepared in conjunction with melamine-formaldehyde crosslinkers as a means of reducing overall coating formaldehyde emissions. Formulations were prepared as listed in Table 3. Waterborne Melamine Formaldehyde (MF) Crosslinker 385 was added as 10% crosslinker solids and compared to the formulation described in C2.1 below. The formaldehyde-free crosslinker was the crosslinker described in Example 2.

[0238] Table 3: Coating composition

[0239]

[0240] Films were prepared by applying the coating compositions of Examples C2.1 and C2.2 onto the surface of 101.6 mm x 152.4 mm (4" x 6") clean glass plates and white basecoated B1000 steel plates and using a wire wound coating rod #50 to spread the applied formulation to obtain a uniform film. The coated panels were then flashed at room temperature for 24 hours under ambient conditions (20-25°C).

[0241] Table 4: Coating properties

[0242] Coating preparation C2.1 C2.2 Dry film thickness, mil 2.6 2.4 Film appearance good good According to Konig's hardness 131 118 Thermal aging yellowing Δb* 1.21 0.24

[0243] Evaluation of the crosslinkable composition of Example 2 in coating composition C2.1 and the crosslinkable composition of Example 2 in combination with a melamine formaldehyde crosslinker in coating composition C2.2 showed that these products provided acceptable coating properties.

[0244] Example C3 : The crosslinker composition products of Example 10 and Example 7 were used to prepare coating compositions.

[0245] The coating composition was prepared by using the ingredients listed in Table 5 below. Acrylic emulsion EMP 9524 (corresponding to a hydroxy-functional acrylic resin having sulfonic acid groups incorporated into the polymer, examples of such resins being described in US 2014 / 0243469A1) was added to a container equipped with a suitable mixing device, followed by the addition of solvent and the required amount of catalyst ("pTSA" p-toluenesulfonic acid, dissolved in water). The crosslinkers of Examples 10 and 7 (FF crosslinkers) were added and stirred together with the rheology modifier and additional solvent (if necessary) to provide a coating formulation having a solid mass fraction of 40% and a total mass ratio of binder to crosslinker of 80 / 20.

[0246] Table 5: Coating composition

[0247]

[0248] Films were prepared by applying the coating compositions of C3.1 and C3.2 onto the surface of 101.6 mm x 152.4 mm (4" x 6") clean glass plates and white basecoated B1000 steel plates and using a wire wound coating rod #50 to spread the applied formulations to give a uniform film. The coated panels were flashed at room temperature for 10 minutes and then at 65°C for 15 minutes.

[0249] Table 6: Coating properties

[0250] Coating preparation C3.1 C3.2 Dry film thickness, mil 2.4 2.4 Film appearance good good According to Konig's hardness 180 179 Thermal aging yellowing Δb* 1.14 0.84

[0251] Evaluation of the crosslinkable compositions of Examples 10 and 7 in coating compositions C3.1 and C3.2 showed that these products provided acceptable coating properties.

[0252] Example C4 : The coating composition was prepared using the crosslinker composition of Example 11 and Example 8.

[0253] The coating composition was prepared by using the ingredients listed in Table 7 below. Acrylic emulsion EMP 9524 (corresponding to a hydroxy-functional acrylic resin having sulfonic acid groups incorporated into the polymer, examples of such resins being described in US 2014 / 0243469A1) was added to a container equipped with a suitable mixing device, followed by the addition of solvent and the required amount of catalyst ("pTSA" p-toluenesulfonic acid, dissolved in water). The crosslinker of Examples 11 and 8 (FF crosslinker) was added and stirred together with a rheology modifier and additional solvent (if necessary) to provide a coating formulation having a solid mass fraction of 40% and a total mass ratio of binder to crosslinker of 80 / 20.

[0254] Table 7: Coating composition

[0255]

[0256] Films were prepared by applying the coating compositions of Examples C4.1 and C4.2 onto the surfaces of 101.6 mm x 152.4 mm (4" x 6") clean glass panels and white basecoated B1000 steel panels and using a wire wound coating rod #50 to spread the applied formulation to give a uniform film. The coated panels were flashed at room temperature for 10 minutes and then at 65°C for 15 minutes.

[0257] Table 8: Coating properties

[0258] Coating preparation C4.1 C4.2 Dry film thickness, mil 2.6 2.6 Film appearance good good According to Konig's hardness 137 137 Thermal aging yellowing Δb* 1.23 1.35

[0259] Evaluation of the crosslinkable compositions of Examples 11 and 8 in coating compositions C4.1 and C4.2 showed that these products provided acceptable coating properties.

[0260] Example C5 : Use Example 13 to prepare the coating composition.

[0261] The following is an example of a coating composition that demonstrates the use of the crosslinkable composition of the present invention in a high temperature baking application for industrial coatings.

[0262] The coating compositions were prepared by using the ingredients listed in Table 9 below. SM6826 is added to a container equipped with a suitable mixing device, followed by the addition of solvent. The crosslinker of Example 13 (FF crosslinker) is added and stirred together with a rheology modifier and additional solvent (if necessary) to provide a coating formulation having a solid mass fraction of 40% and a total mass ratio of binder to crosslinker of 80 / 20.

[0263] Table 9: Coating composition

[0264]

[0265] Films were prepared by applying the coating composition of C5.1 onto the surface of a 101.6 mm x 152.4 mm (4" x 6") clean glass plate and a white basecoated B1000 steel plate and using a wire wound coating rod #50 to spread the applied formulation to give a uniform film. The coated panels were flashed at room temperature for 10 minutes and then at 125°C for 20 minutes.

[0266] Table 10: Coating properties

[0267] Coating preparation C5.1 Film appearance good According to Konig's hardness 120

[0268] Evaluation of the crosslinkable composition of Example 13 in coating composition C5.1 showed that the product provided acceptable coating properties.

[0269] Example C6 : A coating composition was prepared using the crosslinker composition of Example 4.

[0270] The coating composition was prepared by using the ingredients listed in Table 11 below. Acrylic emulsion EMP 9524 (corresponding to a hydroxy-functional acrylic resin having sulfonic acid groups incorporated into the polymer, examples of such resins are described in US 2014 / 0243469A1) was added to a container equipped with a suitable mixing device, followed by the addition of solvent and the required amount of catalyst (boric acid dissolved in water). The crosslinker of Example 4 was added and stirred together with a rheology modifier and additional solvent (if necessary) to provide a coating formulation having a solid mass fraction of 40% and a total mass ratio of binder to crosslinker of 80 / 20.

[0271] Table 11: Coating composition

[0272]

[0273] Films were prepared by applying the coating compositions of C6.1 and C6.2 onto the surface of 101.6 mm x 152.4 mm (4" x 6") clean glass panels and white basecoated B1000 steel panels and using a wire wound coating rod #50 to spread the applied formulations to obtain a uniform film. The coated panels were cured for 5 days at room temperature.

[0274] Table 12: Coating properties

[0275] Coating preparation C6.1 C6.2 Dry film thickness, mil 1.5 1.9 Film appearance good Fog Thermal aging yellowing Δb* -0.01 -0.02

[0276] Evaluation of the crosslinkable composition of Example 4 in coating compositions C6.1 and C6.2 showed that the product provided acceptable coating properties and low heat aging yellowing in the presence of a boric acid catalyst.

Claims

1. A reaction product H which is the reaction product of at least one cyclic urea U selected from cyclic alkylene ureas, at least one multifunctional aldehyde A selected from divalent aldehydes and at least one polyol P selected from non-vicinal polyols, wherein the reaction product H is obtained in the presence of at least one acid catalyst C selected from organic acid catalysts, and wherein the ratio of the amount of the reacted polyol P to the amount of the at least one cyclic urea U is at least 0.01:1 mol / mol.

2. The reaction product H according to claim 1, wherein the at least one polyol P is selected from 1,6-hexanediol, 2-methyl-1,3-propanediol, 2-ethyl-1,2-hydroxymethyl-1,3-propanediol, trimethylolpropane, tri(hydroxymethyl)ethane, cyclohexanedimethanol, neopentyl glycol, trimethylpentanediol, dimethylolpropionic acid and pentaerythritol.

3. The reaction product H according to claim 1 or 2, wherein the at least one polyol P is selected from 2-methyl-1,3-propanediol, 2-ethyl-1,2-hydroxymethyl-1,3-propanediol, trimethylolpropane and 1,6-hexanediol.

4. The reaction product H according to claim 1 or 2, wherein the polyol P is 2-methyl-1,3-propanediol.

5. The reaction product H according to claim 1 or 2, wherein the at least one acid catalyst C is selected from citric acid, succinic acid, lactic acid, tartaric acid and mixtures thereof.

6. Reaction product H according to claim 5, wherein the at least one acid catalyst C is citric acid.

7. The reaction product H according to claim 1 or 2, wherein the at least one cyclic urea U is selected from ethylene urea, 1,3-propylene urea, 1,2-propylene urea, 1,4-butylene urea, glycoluril and mixtures thereof.

8. The reaction product H according to claim 1 or 2, wherein the at least one multifunctional aldehyde A is selected from the group consisting of glyoxal, malondialdehyde, succindialdehyde, glutaraldehyde and mixtures thereof.

9. The reaction product H according to claim 1 or 2, which is unetherified or etherified.

10. A method for preparing the reaction product H according to any one of claims 1 to 9, comprising the following steps: a) mixing at least one cyclic urea U selected from cyclic alkylene ureas and at least one polyfunctional aldehyde A selected from divalent aldehydes to carry out an addition reaction in the presence of at least one base B, wherein the base does not react with any of the polyfunctional aldehyde A, the cyclic urea U and the reaction product H, wherein in step a), at least one polyol P selected from non-vicinal polyols is mixed into the at least one polyfunctional aldehyde A and the at least one cyclic urea U, and in the subsequent step b') at least one acid catalyst C selected from organic acid catalysts is mixed; or in the subsequent step b), the at least one polyol P and the at least one acid catalyst C are mixed; and The ratio of the amount of polyol P reacted to the amount of the at least one cyclic urea U is at least 0.01:1 mol / mol. 11 . The process according to claim 10 , wherein the ratio of the amount of substance of the at least one multifunctional aldehyde A to the amount of substance of the at least one cyclic urea U is 0.8:1 to 1.4:1 mol / mol. 12 . The process according to claim 10 , wherein the ratio of the amount of substance of the at least one polyol P to the amount of substance of the at least one cyclic urea U is from 0.01:1 to 1:1 mol / mol.

13. The process according to claim 10 or 11, wherein the at least one polyol P is admixed to the at least one cyclic urea U, the at least one polyfunctional aldehyde A and the at least one base B in a subsequent step b).

14. A coating composition comprising the reaction product H according to any one of claims 1 to 9.

15. The coating composition according to claim 14, further comprising at least one crosslinkable resin and optionally water and / or optionally at least one organic solvent.

16. The coating composition of claim 15, wherein the crosslinkable resin is an oligomeric or polymeric material having at least one functional group having an active hydrogen atom, wherein the functional group is selected from the group consisting of a hydroxyl functional group, an acid functional group, an amide functional group, an amino functional group, an imino functional group, an imide functional group, a thiol functional group, a phosphine functional group, and a carbamate functional group.

17. The coating composition according to any one of claims 14 to 16, which is an aqueous coating composition.

18. The coating composition according to any one of claims 14 to 16, which is an aqueous coating composition using a hydroxyl-functional acrylic resin having sulfonic acid groups incorporated into a polymer as a crosslinkable resin.

19. The coating composition according to any one of claims 14 to 16, further comprising a catalyst CB which is an acid catalyst selected from the group consisting of organic sulfonic acids, organic phosphonic acids, organic sulfonimides, organic carboxylic acids and Lewis acids, salts or complexes of Lewis acids, or inorganic acids.

20. A method of using the reaction product H according to any one of claims 1 to 9 as a crosslinking agent, comprising applying the reaction product H to a substrate.

21. The process according to claim 20, comprising mixing the reaction product H with at least one crosslinkable resin and optionally with water and / or optionally with at least one organic solvent, homogenizing and applying the homogenized mixture to a substrate.

22. The method of claim 20 or 21, wherein the substrate is selected from the group consisting of plastic, wood, ceramic, glass, leather, textile, tire cord, rubber objects, paper, cardboard, plaster, concrete, metal, and semiconductor surfaces.

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