Polyamide amine, curable composition, curing agent, and coating material

Abstract

The present invention addresses the problem of providing a polyamide amine which is capable of providing a water-soluble curing agent. The present invention also addresses the problem of providing a curable composition, a curing agent, and applications such as a coating material. The present invention relates to a polyamide amine which is obtained by reacting a polyamine and an acid component that contains a mono fatty acid and a dimer acid. In this polyamide amine: the mono fatty acid includes a hydroxyl group-containing mono fatty acid that contains at least one hydroxyl group and a hydroxyl group-free mono fatty acid that does not contain a hydroxyl group; the polyamine includes a polyethylene polyamine; the molar ratio of the polyamine to the dimer acid is 2.5 to 15 inclusive; and the weight ratio of the total amount of the dimer acid and the hydroxyl group-containing mono fatty acid to the hydroxyl group-free mono fatty acid is 2.0 or more.

Description

Polyamidoamine, curable composition, curing agent, and coating material

[0001] The present invention relates to a polyamidoamine, a curable composition, a curing agent (epoxy resin-modified polyamidoamine), and uses thereof (for example, paints).

[0002] Polyamidoamines are known as curing agents for epoxy resins and the like, and are used in a variety of applications. For example, known polyamidoamine compositions include a reaction product of a fatty acid with an amine component containing a polyfunctional amine having a specific structure (see, for example, Patent Documents 1 and 2). Also known is an aliphatic polyamidoamine composition obtained by condensing a dimer acid component containing 50% by weight or more of at least one selected from specific chain dimer acids and their esters with an alkylene polyamine having 4 to 20 carbon atoms in a specific ratio (see, for example, Patent Document 3).

[0003] JP 2019-503430 A JP 2008-7776 A JP 5-156004 A

[0004] In recent years, in order to address environmental issues, attention has shifted from solvent-based materials to water-soluble materials, and for example, in the field of paints, there is a demand for water-soluble materials such as water-soluble curing agents that can be used in water-soluble paints. In addition, the curing agents are also required to be stable during storage.

[0005] Patent Documents 1 to 3 do not consider at all a water-soluble curing agent in which a portion of polyamidoamine is modified with an epoxy resin (epoxy resin-modified polyamidoamine), nor do they consider at all making polyamidoamine into a specific composition in order to form the water-soluble curing agent.

[0006] Therefore, an object of the present invention is to provide a polyamidoamine that can provide a water-soluble curing agent in which a portion of the polyamidoamine is modified with an epoxy resin (epoxy resin-modified polyamidoamine), and further to provide applications of the polyamidoamine in curable compositions, curing agents, coating materials, etc.

[0007] As a result of extensive research, the present inventors have newly discovered that by reacting a polyamine with an acid component containing a hydroxyl group-containing mono-fatty acid and a dimer acid to produce a polyamidoamine, the polyamidoamine can be reacted with an epoxy resin to provide a water-soluble curing agent in which a portion of the polyamidoamine is modified with the epoxy resin (epoxy resin-modified polyamidoamine), and that the water-soluble curing agent has excellent storage stability, which has led to the completion of the present invention.

[0008] That is, the present invention relates to a polyamidoamine obtained by reacting a polyamine with an acid component containing a mono-fatty acid and a dimer acid, wherein the mono-fatty acid comprises a hydroxyl group-containing mono-fatty acid containing at least one hydroxyl group, and a hydroxyl-free mono-fatty acid containing no hydroxyl groups, the polyamine comprises a polyethylene polyamine, the molar ratio of the polyamine to the dimer acid is 2.5 or more and 15 or less, and the weight ratio of the total amount of the dimer acid and the hydroxyl group-containing mono-fatty acid to the hydroxyl-free mono-fatty acid is 2.0 or more.

[0009] Preferably, the fatty monoacid comprises ricinoleic acid.

[0010] The present invention also relates to a curable composition containing the polyamidoamine, a curing agent obtained by reacting the polyamidoamine in the curable composition with an epoxy resin, and a coating material containing the curing agent.

[0011] 1. Polyamidoamine The polyamidoamine of the present invention is obtained by reacting a polyamine with an acid component containing a mono-fatty acid and a dimer acid, wherein the mono-fatty acid comprises a hydroxyl-containing mono-fatty acid containing at least one hydroxyl group and a non-hydroxyl-containing mono-fatty acid containing no hydroxyl groups, the polyamine comprises a polyethylene polyamine, the molar ratio of the polyamine to the dimer acid is 2.5 or more and 15 or less, and the weight ratio of the total amount of the dimer acid and the hydroxyl-containing mono-fatty acid to the non-hydroxyl-containing mono-fatty acid ((total weight of dimer acid and hydroxyl-containing mono-fatty acid) / weight of non-hydroxyl-containing mono-fatty acid) is 2.0 or more. The molar ratio of the polyamine to the dimer acid is the molar ratio of the polyamine to the dimer acid in the feedstock. The weight ratio of the total amount of the dimer acid and the hydroxyl-containing mono-fatty acid to the non-hydroxyl-containing mono-fatty acid is the total weight of the dimer acid and the hydroxyl-containing mono-fatty acid to the weight of the non-hydroxyl-containing mono-fatty acid in the feedstock. Each component constituting the polyamidoamine of the present invention will be described below.

[0012] 1-1. Acid Component The acid component used in the present invention contains a dimer acid and a hydroxyl group-containing mono-fatty acid, and may contain other acid components such as a trimer acid.

[0013] (Dimer Acid) The dimer acid is a dibasic acid obtained by dimerizing a monobasic unsaturated fatty acid having 10 to 22 carbon atoms. Typical raw materials include unsaturated fatty acids such as linolenic acid, linoleic acid, oleic acid, elaidic acid, and erucic acid, and among these, dimerization products of oleic acid and / or linoleic acid are preferred.

[0014] Most commercially available dimer acids are made from unsaturated fatty acids having 18 carbon atoms, and therefore the main component is a dicarboxylic acid having 36 carbon atoms. Examples of the structure of dimer acids include, but are not limited to, the following:

[0015] The dimer acid may be either a synthetic product or a commercially available product. Commercially available products may be provided as a composition of various mixtures, specifically containing monomer acids (unreacted substances, isomer components, etc.), dimer acids (main components), trimer acids, etc. (by-products), and there are various specifications depending on the content ratios of these.

[0016] Commercially available dimer acids include, for example, Tsunodyme 205, Tsunodyme 216, and Tsunodyme 395 (hereinafter abbreviated as Td205, Td216, and Td395, respectively, all manufactured by Tsuno Oleochemicals Co., Ltd.), and Haridimer 200 (manufactured by Harima Chemicals Co., Ltd.). Of these, Td216, Td395, and Haridimer 200 are preferred.

[0017] The compositions of the commercially available products are as follows: Each composition can be measured by liquid chromatography, gas chromatography, or the like, but in the present disclosure, the values ​​are measured using liquid chromatography.

[0018]

[0019] The dimer acid is preferably present in an amount of 10% by weight or more, more preferably 14% by weight or more, based on the total amount of acid components (100% by weight), and is preferably present in an amount of 60% by weight or less, more preferably 55% by weight or less, and even more preferably 50% by weight or less, based on the total amount of acid components (100% by weight).

[0020] When the acid component further contains the trimer acid, the trimer acid is preferably contained in an amount of 15% by weight or less, more preferably 10% by weight or less, based on the total amount of the acid component (100% by weight).

[0021] (Monofatty acids) The monofatty acids used in the present invention may be any fatty acids including hydroxyl-containing monofatty acids having at least one hydroxyl group in their structure and hydroxyl-free monofatty acids not containing any hydroxyl group, and may be saturated fatty acids, unsaturated fatty acids, straight-chain fatty acids, or branched fatty acids. Here, the hydroxyl group does not include the hydroxyl group constituting a carboxyl group.

[0022] Specific examples of hydroxyl group-containing mono-fatty acids include ricinoleic acid, 12-hydroxystearic acid, 2-hydroxytetradecanoic acid, iprolic acid, 2-hydroxyhexadecanoic acid, jalapinolic acid, uniperinic acid, ambrettolic acid, alluritic acid, 2-hydroxyoctadecanoic acid, 18-hydroxyoctadecanoic acid, 9,10-dihydroxyoctadecanoic acid, camrolenoic acid, ferronic acid, and cerebronic acid. Hydroxyl group-containing mono-fatty acids may be used alone or in combination of two or more. Of these, ricinoleic acid is preferred as the hydroxyl group-containing mono-fatty acid.

[0023] Examples of mono-fatty acids containing hydroxyl group-containing mono-fatty acids include castor oil fatty acids, such as CO-FA (manufactured by Ito Oil Mills, Ltd.), CO-FA-S (manufactured by Kokura Synthetic Industries, Ltd.), and CO-FA (manufactured by Toyokuni Oil Mills, Ltd.).

[0024] The hydroxyl group-containing mono-fatty acid is preferably used in an amount of 5% by weight or more, more preferably 7% by weight or more, and preferably 60% by weight or less, based on the total amount (100% by weight) of the acid component and the polyamine. Here, the amount of hydroxyl group-containing mono-fatty acid used is the total of all hydroxyl group-containing mono-fatty acids contained in the raw material feed, specifically, the total amount of the added hydroxyl group-containing mono-fatty acid and, if present, the amount of hydroxyl group-containing mono-fatty acid contained in the commercially available dimer acid (unreacted substances, isomer components, etc.). By setting the amount of hydroxyl group-containing mono-fatty acid used within the above range, the storage stability of the resulting water-soluble curing agent can be improved, which is preferable.

[0025] The non-hydroxyl group-containing mono-fatty acid may be a saturated fatty acid or an unsaturated fatty acid, and may be a straight-chain fatty acid or a branched fatty acid. Specifically, for example, dodecanoic acid (lauric acid), tetradecanoic acid (myristic acid), hexadecanoic acid (palmitic acid), octadecanoic acid (stearic acid, isostearic acid), tetradecadienoic acid, hexadecadienoic acid, octadecadienoic acid (linoleic acid, etc.), eicosadienoic acid, docosadienoic acid, octadecatrienoic acid (linolenic acid, etc.), eicosatetraenoic acid (arachidonic acid, etc.), tetradecenoic acid (tsuzunic acid, physeteric acid, myristoleic acid), hexadecenoic acid (palmitoleic acid, etc.), octadecenoic acid (oleic acid, isooleic acid, elaidic acid, vaccenic acid, etc.), eicosenoic acid (gadoleic acid, etc.), and docosenoic acid (erucic acid, cetoleic acid, brassidic acid, etc.) and other fatty acids having 10 to 22 carbon atoms can be mentioned, but are not limited to these. In addition, these can be used alone or in combination of two or more.

[0026] The non-hydroxyl group-containing mono-fatty acid preferably contains a fatty acid having 16 to 18 carbon atoms, and preferably contains one or more non-hydroxyl group-containing mono-fatty acids selected from the group consisting of palmitic acid, stearic acid, oleic acid, isostearic acid, linoleic acid, and linolenic acid, and more preferably contains oleic acid and / or linoleic acid.

[0027] As the hydroxyl group-free mono fatty acid, commercially available products can also be used, such as TFA-140F, TFA-47, and TFA-80MS (all manufactured by Tsuno Oleochemicals Co., Ltd.).

[0028] When the hydroxyl group-free mono fatty acid is used, its content is not particularly limited, but it is preferably used in an amount of 30% by weight or less, and more preferably 25% by weight or less, relative to the total amount (100% by weight) of the acid component and the polyamine.

[0029] The weight ratio of the total amount of dimer acid and hydroxyl group-containing mono fatty acid to the hydroxyl group-free mono fatty acid is in the range of 2.0 or more, preferably 2.5 or more, and is preferably 8.0 or less, more preferably 7.5 or less.

[0030] 1-2. Polyamine The polyamine used in the present invention includes polyethylene polyamine. The polyethylene polyamine can be represented by, for example, the following formula (1): H ２ N (C ２ H ４ NH) ｎ H (1) (In formula (1), n ​​is 2 or more.)

[0031] In the formula (1), n ​​is 2 or more, and preferably 2 or more and 6 or less.

[0032] Examples of polyethylene polyamines represented by formula (1) include diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, hexaethyleneheptamine, heptaethyleneoctamine, octaethylenenonamine, and nonaethylenedecamine. Among these, triethylenetetramine and tetraethylenepentamine are preferred. The polyethylene polyamines may be used alone or in combination of two or more.

[0033] The polyethylene polyamine is preferably used in an amount of 15% by weight or more, more preferably 20% by weight or more, and preferably 35% by weight or less, more preferably 30% by weight or less, based on the total amount (100% by weight) of the acid component and the polyamine. When the amount of polyethylene polyamine used is within the above range, the storage stability of the resulting water-soluble curing agent can be improved, which is preferable.

[0034] The polyamine used in the present invention may contain, in addition to polyethylene polyamine, other polyamines, such as aliphatic polyamines (e.g., polyalkylene polyamines such as polypropylene polyamines), alicyclic polyamines, aromatic polyamines, and heterocyclic amines.

[0035] Examples of aliphatic polyamines include ethylenediamine, trimethylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, triaminopropane, and diethylenetriamine. Examples of alicyclic polyamines include 1,4-cyclohexanediamine, diaminodicyclohexylmethane, 4,4'-isopropylidenebiscyclohexylamine, norbornanediamine, bis(aminomethyl)cyclohexane, isophoronediamine, 1,3-bisaminomethylcyclohexane, menthenediamine (MDA), and 2,4-di(4-aminocyclohexylmethyl)aniline. Examples of aromatic polyamines include phenylenediamine, metaxylylenediamine, paraxylylenediamine, and diaminodiphenylmethane. Examples of heterocyclic amines include 1,4-diazacycloheptane, 1,11-diazacycloeicosane, and 1,15-diazacyclooctacosane. In the present invention, these polyamines may be used alone or in combination of two or more polyamines.

[0036] The amount of the other polyamine is preferably 35% by weight or less, and more preferably 30% by weight or less, based on the total amount (100% by weight) of the acid component and the polyamine.

[0037] In the present invention, the molar ratio of polyamine to dimer acid (polyamine / dimer acid) is 2.5 or more, more preferably 2.7 or more, and even more preferably 3.0 or more. The upper limit of the molar ratio is 15 or less, preferably 12 or less, more preferably 11 or less, even more preferably 10 or less, and particularly preferably 9 or less. When the molar ratio is within the above range, the curing agent obtained by reacting polyamidoamine with epoxy resin (polyamidoamine partially modified with epoxy resin) becomes water-soluble and has excellent storage stability.

[0038] The polyamidoamine of the present invention can be obtained by reacting the acid component with the polyamine. The reaction conditions are not particularly limited and can be varied depending on the type of acid component and polyamine. The reaction temperature can be, for example, 60°C to 300°C, and preferably 100°C to 250°C. The reaction can be terminated as soon as the reaction between the acid component and the polyamine is complete. Specifically, the reaction can be terminated when the acid value of the reaction solution becomes less than 3.0 mgKOH / g, and preferably less than 1.5 mgKOH / g. The reaction time is typically from 0.5 hours to 10 hours, and preferably from 1 hour to 5 hours.

[0039] The composition of the resulting polyamidoamine is approximately the same as the composition ratio of the raw materials charged, as will be shown in the examples described later.

[0040] The polyamidoamine of the present invention may be a polyamidoamine obtained by reacting a polyamine with an acid component containing a mono-fatty acid and a dimer acid, wherein the molar ratio of the polyamine to the dimer acid is 2 or more and 4 or less, and the polyamidoamine may exclude a polyamidoamine in which the mono-fatty acid accounts for 30% by weight or more and 45% by weight or less of the total amount of the acid component and the polyamine.

[0041] 2. Polyamidoamine-forming composition The polyamidoamine-forming composition of the present invention comprises a polyamine and an acid component including a fatty mono-acid and a dimer acid, wherein the fatty mono-acid comprises a hydroxyl group-containing fatty mono-acid containing at least one hydroxyl group, and a non-hydroxyl group-containing mono-acid containing no hydroxyl groups, the polyamine comprises a polyethylene polyamine, the molar ratio of the polyamine to the dimer acid is 2.5 or more and 15 or less, and the weight ratio of the total amount of the dimer acid and the hydroxyl group-containing mono-acid to the non-hydroxyl group-containing mono-acid is 2.0 or more.

[0042] The acid component, polyamine, and various contents and molar ratios are as described above.

[0043] The polyamidoamine can be formed by subjecting the polyamidoamine-forming composition to a reaction under the reaction conditions as described above.

[0044] 3. Curable Composition The curable composition of the present invention contains the polyamidoamine. The polyamidoamine in the curable composition can cure the epoxy resin.

[0045] The curable composition may contain any of the polyamidoamines, and may also contain other solvents such as aromatic hydrocarbon solvents, such as toluene and xylene, and alcohol solvents, such as n-butanol, isobutanol, and methanol.

[0046] The present invention relates to a curing agent (epoxy resin-modified polyamidoamine) obtained by reacting the polyamidoamine in the curable composition with an epoxy resin, in which a portion of the polyamidoamine is modified with an epoxy resin. The curing agent of the present invention can be used as a curing agent for paints and the like.

[0047] The curable composition is as described above.

[0048] The epoxy resin is not particularly limited as long as it can react with the polyamidoamine in the curable composition, and for example, a bisphenol-type epoxy resin can be used, such as bisphenol A or bisphenol F. Also, a (poly)alkylene glycol-type diglycidyl ether such as (poly)ethylene glycol-type diglycidyl ether can be used.

[0049] From the viewpoint of providing a solution with a viscosity suitable for coating, such bisphenol-type epoxy resins preferably have a weight-average molecular weight of about 300 to 10,000, more preferably about 300 to 1500. Furthermore, the epoxy equivalent is not particularly limited, but is preferably, for example, 150 to 1,000 g / eq, more preferably 350 to 600 g / eq.

[0050] The weight-average molecular weight of the (poly)alkylene glycol type diglycidyl ether epoxy resin is preferably about 200 to 1,000, and more preferably about 200 to 600. The epoxy equivalent is not particularly limited, but is preferably, for example, 100 to 400 g / eq, and more preferably 100 to 300 g / eq.

[0051] Examples of bisphenol-type epoxy resins include bisphenol A-type epoxy resins such as jER825, jER827, jER828, jER834, jER834X90, jER1001, jER1001X70, jER1001X75, and jER1001T75 manufactured by Mitsubishi Chemical Corporation, ADEKA RESIN EP-4100 manufactured by Adeka Corporation, and Epotohto YD-128 and YD-011X75 manufactured by Nippon Steel & Sumikin Chemical Co., Ltd. Examples of bisphenol F-type epoxy resins include jER806, jER806H, and jER807 manufactured by Mitsubishi Chemical Corporation, and EPICLON 830 and EPICLON 835 manufactured by DIC Corporation. Examples of (poly)alkylene glycol type diglycidyl ethers include DECONAL EX810 and DECONAL EX830 manufactured by Nagase ChemteX Corp. These may be used alone or in combination of two or more.

[0052] The amount of polyamidoamine used relative to the epoxy resin is not particularly limited, and can be appropriately determined based on the active hydrogen equivalent of the polyamidoamine and the epoxy equivalent of the epoxy resin. For example, the active hydrogen equivalent of the polyamidoamine relative to the epoxy equivalent of the epoxy resin is preferably 2.0 to 13.0 equivalents, more preferably 3.0 to 12.0 equivalents, and even more preferably 4.0 to 10.0 equivalents.

[0053] The reaction conditions for the polyamidoamine and epoxy resin are not particularly limited and can be varied appropriately depending on the composition of the polyamidoamine and the type of epoxy resin. For example, the reaction can be carried out at a temperature of 10°C to 300°C for approximately 0.5 to 5 hours, or at a temperature of 50°C to 150°C for approximately 0.5 to 1.5 hours. Furthermore, in the reaction, alcoholic solvents such as 2-butoxyethanol, 2-propoxyethanol, propylene glycol monomethyl ether, and ethylene glycol monobutyl ether, as well as water and acetic acid, may be used alone or in combination, as needed. After the reaction, the solvent may be distilled off and used as a curing agent, or the resulting curing agent solution may be used directly without distillation.

[0054] By reacting the polyamidoamine in the curable composition of the present invention with an epoxy resin, a curing agent (epoxy resin-modified polyamidoamine) in which a portion of the polyamidoamine is modified with an epoxy resin can be obtained. The curing agent is water-soluble. Here, "water solubility" can be evaluated by preparing an aqueous solution of the obtained curing agent (epoxy resin-modified polyamidoamine) and measuring the transmittance of the aqueous solution. Specifically, a transmittance of 80% or more, as measured by the method described in the Examples, is considered to be "water-soluble," and a transmittance of less than 80% is considered to be "water-insoluble."

[0055] 5. Uses The curing agent of the present invention can be used for various purposes, and can also be used as a crosslinking agent for water-soluble resins. Specific uses include, for example, paints, fiber and paper reinforcing agents, adhesives, etc. Furthermore, a composition may be prepared by adding some additives, solvents, etc. to the curing agent. The curing agent of the present invention is preferably used in paints.

[0056] The coating material can form a coating film by reacting the curing agent with a base resin. Examples of the base resin include epoxy resin, acrylic resin, urethane resin, silicone resin, and fluorine-based resin, with a combination with an epoxy resin being particularly preferred. The coating material may be in the form of a one-component solution containing both the base resin and the curing agent of the present invention, or a two-component solution in which solutions containing the base resin and the curing agent of the present invention are mixed immediately before use. After applying the coating material to a substrate, the curing conditions can be appropriately selected, whether at room temperature or under heat, to form a coating film.

[0057] The paint contains the base agent and curing agent, and may also contain other components. Examples of other components include pigments such as titanium dioxide, carbon black, and calcium carbonate, additives such as anti-algae agents, anti-fungal agents, antibacterial agents, anti-sagging agents, and anti-suspending agents, and solvents such as water, ether-based solvents, and alcohol-based solvents. The amounts of these components added are not particularly limited as long as they do not affect the effects of the present invention, and may be used within a desired range.

[0058] In the coating material of the present invention, the content of the curing agent is usually about 10 to 30 wt % of the solid content of the coating material, and preferably about 15 to 25 wt %. By including the curing agent in this range, it is possible to form a coating film that has excellent adhesion to the substrate, which is preferable.

[0059] The coating material of the present invention can be suitably used for painting architectural materials such as the interior and exterior of buildings and exterior walls, and can also be widely used for transportation such as automobiles, railway vehicles, ships, and aircraft, as well as electrical equipment.

[0060] EXAMPLES The present invention will be explained in more detail below by showing examples and comparative examples, but the present invention is not limited to the following examples.

[0061] [Raw Materials for Polyamidoamine] The raw materials used in the production of polyamidoamine are as follows. (Dimer Acid) Td216: Trade Name, Manufactured by Tsuno Oleochemicals Co., Ltd. Haridimer 200: Trade Name, Manufactured by Harima Chemicals Co., Ltd. The composition of the dimer acid is as shown in Table 1 above. (Hydroxyl Group-Containing Mono Fatty Acid) CO-FA: Trade Name, Manufactured by Ito Oil Mills, Ltd. The hydroxyl value of the CO-FA was 152.3 mg KOH / g. The hydroxyl value can be measured according to the Standard Methods for the Analysis of Fats, Oils, and Related Compounds (2.3.6.2-2013). The ricinoleic acid content of the CO-FA was 81% by weight, calculated using the following formula. Components other than ricinoleic acid included palmitic acid, stearic acid, oleic acid, linoleic acid, and linolenic acid, which were measured by gas chromatography (GC) at 1%, 1%, 4%, 4%, and 1%, respectively, for a total of 19% by weight. (Calculation formula) Theoretical hydroxyl value of ricinoleic acid (100% product) = 56,100 / 298.5 (*) = 188 Purity of ricinoleic acid in CO-FA (%) = 152.3 / 188 x 100 = 81 (*) Molecular weight of ricinoleic acid (Hydroxyl group-free mono fatty acid) TFA-140F: Trade name, manufactured by Tsuno Oleochemicals Co., Ltd. TFA-47: Trade name, manufactured by Tsuno Oleochemicals Co., Ltd. (Polyamine) TETA: Triethylenetetramine TEPA: Tetraethylenepentamine

[0062] Example 1 A 1 L four-neck flask equipped with a stirrer, thermometer, dehydrator, and condenser was charged with 100 g of dimer acid (trade name: Td216, manufactured by Tsuno Oleochemicals Co., Ltd.), 433 g of mono-fatty acid (trade name: CO-FA, manufactured by Ito Oil Mills Co., Ltd.), and 182 g of triethylenetetramine (TETA), and the mixture was heated to 225°C under a nitrogen atmosphere. After reaching 225°C, the reaction was carried out with stirring for approximately 2 hours while removing the generated water. The reaction was terminated when the acid value of the reaction solution reached 0.7 mgKOH / g, and the mixture was cooled to obtain 670 g of polyamidoamine. 143 g of the obtained polyamidoamine, 67 g of epoxy resin A (trade name: Epotohto YD011X75 bisphenol A-type liquid epoxy resin, viscosity (25°C) 8500 mPa s, epoxy equivalent as solids: 475 g / eq, non-volatile content: 75%, manufactured by Nippon Steel Chemical & Material Co., Ltd.), 70 g of 2-butoxyethanol, 60 g of 2-propoxyethanol, and 11 g of 90% acetic acid were charged into a reaction vessel, and the temperature was raised to 100°C. After reaching 100°C, the mixture was reacted with stirring for 1 hour, yielding a solution containing a curing agent (epoxy resin-modified polyamidoamine).

[0063] (Examples 2 to 9, 13, Comparative Examples 1 to 4) Solutions containing a curing agent (epoxy resin-modified polyamidoamine) were obtained in the same manner as in Example 1, except that the types and amounts of dimer acid, mono-fatty acid, polyamine, polyamidoamine, epoxy resin, diluent, and solvent were changed as shown in Tables 2-1, 2-2, 3-1, and 3-2.

[0064] Example 10 A polyamidoamine was obtained in the same manner as in Example 1, except that the types and amounts of dimer acid, mono-fatty acid, and polyamine were changed as shown in Table 2-1. 158 g of the obtained polyamidoamine, 42 g of Epoxy Resin B (trade name: jER828, bisphenol A-type liquid epoxy resin, viscosity (25°C): 12,500 mPa·s, epoxy equivalent: 190 g / eq, manufactured by Mitsubishi Chemical Corporation), 11 g of PEG#200 (manufactured by Lion Specialty Chemicals Co., Ltd.), 70 g of 2-butoxyethanol, 60 g of 2-propoxyethanol, and 11 g of 90% acetic acid were charged into a reaction vessel and heated to 100°C. After reaching 100°C, the mixture was allowed to react with stirring for 1 hour to obtain a solution containing a curing agent (epoxy resin-modified polyamidoamine).

[0065] Example 11 A polyamidoamine was obtained in the same manner as in Example 1, except that the types and amounts of dimer acid, mono-fatty acid, and polyamine were changed as shown in Table 2-1. 214 g of the obtained polyamidoamine, 32 g of Epoxy Resin B (trade name: jER828), 35 g of 2-butoxyethanol, 60 g of 2-propoxyethanol, and 11 g of 90% acetic acid were charged into a reaction vessel and heated to 100°C. After reaching 100°C, the mixture was reacted with stirring for 1 hour to obtain a solution containing a curing agent (epoxy resin-modified polyamidoamine).

[0066] Example 12 A polyamidoamine was obtained in the same manner as in Example 1, except that the types and amounts of dimer acid, fatty monoacid, and polyamine were changed as shown in Table 2-1. 228 g of the obtained polyamidoamine, 53 g of Epoxy Resin B (trade name: jER828), 60 g of 2-propoxyethanol, and 11 g of 90% acetic acid were charged into a reaction vessel and heated to 100°C. After reaching 100°C, the mixture was reacted with stirring for 1 hour to obtain a solution containing a curing agent (epoxy resin-modified polyamidoamine).

[0067] Example 14 238 g of the polyamidoamine obtained in Example 12, 24 g of Epoxy Resin B (trade name: jER828), 77 g of 2-propoxyethanol, and 11 g of 90% acetic acid were charged into a reaction vessel and heated to 100°C. After reaching 100°C, the mixture was reacted with stirring for 1 hour to obtain a solution containing a curing agent (epoxy resin-modified polyamidoamine). As a result of the <Evaluation of water solubility: transmittance (%) of aqueous curing agent solution> described below, the transmittance was 96%, indicating that the solution was water soluble.

[0068] Comparative Example 5 A polyamidoamine was obtained in the same manner as in Example 1, except that the types and amounts of dimer acid, mono-fatty acid, and polyamine were changed as shown in Table 2-2. 199 g of the obtained polyamidoamine, 46 g of Epoxy Resin B (trade name: jER828), 35 g of 2-butoxyethanol, 60 g of 2-propoxyethanol, and 11 g of 90% acetic acid were charged into a reaction vessel and heated to 100°C. After reaching 100°C, the mixture was reacted with stirring for 1 hour to obtain a solution containing a curing agent (epoxy resin-modified polyamidoamine).

[0069] <Evaluation of Water Solubility: Transmittance (%) of Aqueous Curing Agent Solution> 2.1 g of the obtained curing agent (epoxy resin-modified polyamidoamine) solution was mixed with 1.4 g of purified water, and the transmittance at 660 nm of the solution was measured in accordance with JIS K0115:2020. A transmittance of 80% or more was rated as "water soluble," and a transmittance of less than 80% was rated as "water insoluble." The results are shown in Tables 3-1 and 3-2.

[0070] <Evaluation of Stability of Aqueous Curing Agent Solution> The solutions prepared in the above <Evaluation of Water Solubility: Transmittance (%) of Aqueous Curing Agent Solution> were stored in an oven at 50°C for 7 days, and the transmittance was measured under the same conditions as in the above <Evaluation of Water Solubility: Transmittance (%) of Aqueous Curing Agent Solution>. If the transmittance after storage was 80% or higher, the stability was evaluated as "good."

[0071] Tables 2-1 and 2-2 below show the compositions of polyamidoamines in Examples and Comparative Examples, and Tables 3-1 and 3-2 show the compositions and evaluation results of curing agents (epoxy resin-modified polyamidoamines).

[0072]

[0073]

[0074]

[0075]

[0076] In Table 3-2, "-" indicates that the measurement was not performed due to water insolubility.

[0077] The polyamidoamine active hydrogen equivalent (g / eq), adduct ratio, and active hydrogen equivalent of polyamidoamine relative to the epoxy equivalent of epoxy resin in Tables 3-1 and 3-2 were calculated using the following formulas.

[0078] In the above formula, the amount of amide dehydration is a value calculated by the following formula: Amount of amide dehydration (g)={Amount of dimer acid charged (g)×0.79 / 560×2+(Amount of dimer acid charged (g)×0.09+Amount of mono-fatty acid charged (g)) / 281.9}×18

[0079] Adduct ratio (%)=(epoxy resin charge (g) / epoxy equivalent (g / eq)) / (polyamidoamine charge (g) / polyamidoamine active hydrogen equivalent (g / eq))×100

[0080] Active hydrogen equivalent of polyamidoamine relative to epoxy equivalent of epoxy resin=(charged amount of polyamidoamine (g) / active hydrogen equivalent of polyamidoamine (g / eq)) / (charged amount of epoxy resin excluding diluent solvent (g) / active hydrogen equivalent of epoxy resin (g / eq))

[0081] The above results demonstrate that the curing agent (epoxy resin-modified polyamidoamine) of the present invention is water-soluble, whereas the curing agent (epoxy resin-modified polyamidoamine) obtained in the comparative example is water-insoluble.

[0082] <Weight-Average Molecular Weight and Number-Average Molecular Weight of Polyamidoamine> The weight-average molecular weight (Mw) and number-average molecular weight (Mn) of the polyamidoamines obtained in Examples 2, 6, and 8 and Comparative Example 2 were measured. The measurement method involved dissolving the obtained polyamidoamine in tetrahydrofuran (THF), filtering the resulting solution through a filter with a pore size of 0.45 μm, and measuring the molecular weight (Mn) by gel permeation chromatography (GPC) (in terms of polystyrene). The measurement conditions were as follows: Apparatus: HLC-8320GPC (manufactured by Tosoh Corporation) Mobile phase: 0.5 wt% triethylamine / THF Flow rate: 0.3 mL / min Column temperature: 45°C Column: HSPgel HR 1.0, 2.0, 2.5 (manufactured by Waters) Detector: RI detector

[0083]

[0084] From the above results, it was found that the average molecular weights of Example 2 and Comparative Example 2 were almost the same, but the obtained curing agent (epoxy resin-modified polyamidoamine) was water-soluble in Example 2 and water-insoluble in Comparative Example 2. This revealed that there is no correlation between the average molecular weight of polyamidoamine and the water solubility of the obtained curing agent (epoxy resin-modified polyamidoamine).

[0085] <Content of Free Polyamine (Unreacted Polyamine) in Polyamidoamine> 0.2 g of the polyamidoamine obtained in Examples 2, 5, 6, and 8 and Comparative Examples 1 to 3 was placed in a 15 mL screw tube, and 9.8 g of chloroform was added to prepare a 2 wt % chloroform solution. The screw tube was thoroughly shaken to completely dissolve the polyamidoamine. The solution was measured by gas chromatography (GC) under the following conditions. Quantitative analysis was performed using an absolute calibration curve method to identify the amount of free polyamine (amount of unreacted polyamine). Apparatus: Gas Chromatograph GC-2014 (Shimadzu Corporation) Column: ULBON HR-1 (Shimadzu GLC Corporation) Column temperature: 100°C Injection temperature: 280°C Injection volume: 2.5 μL Detector: FID (detection at 280°C)

[0086]

[0087] From the above results, it was found that in the Examples and Comparative Examples, most of the polyamine used was used in the reaction.

[0088] <Polyamidoamine Composition Analysis> (Measurement of Mono-Fatty Acid, Dimer Acid, and Trimer Acid Amounts in Polyamidoamine) 3.5 g of the polyamidoamine obtained in Example 5, 5 g of potassium hydroxide, and 20 g of purified water were mixed to prepare an aqueous solution. The resulting aqueous solution was treated at 165°C for 120 hours, cooled to room temperature, and neutralized with 10 g of 12N HCl. 50 mL of petroleum ether (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was added to the neutralized aqueous solution, and the mixture was thoroughly shaken to separate into an organic layer and an aqueous layer. 50 mL of petroleum ether was added to the separated aqueous layer, and the same extraction procedure was repeated three times. The petroleum ether was distilled off from the resulting organic layer using a rotary evaporator to obtain 2.52 g of sample. The amount of mono-fatty acid, dimer acid, and trimer acid in the polyamidoamine was measured by high-performance liquid chromatography (HPLC) under the following conditions. The mono-fatty acids, dimer acids, and trimer acids were quantified based on the mono-fatty acids (CO-FA, TFA-140F) calibration curves prepared under the same conditions. Furthermore, the mono-fatty acids, dimer acids, and trimer acids in the polyamidoamine of Example 6 were quantified in the same manner. Apparatus: High-performance liquid chromatograph AS8020, CO8020, DP8020, SD-8022 (manufactured by Tosoh Corporation) Column: TSKgel Silica-60, φ4.6 × 250 mm (manufactured by Tosoh Corporation) Column temperature: 40°C Flow rate: 1.2 mL / min Sample injection volume: 10, 20, 30 μL Detector: ELSD (Evaporative Light Scattering Detector) Detection temperature: 40°C Pressure: 350 kPa Gain: 1

[0089] (Measurement of the amount of polyamine components in polyamidoamine) Furthermore, the water layer (petroleum ether-insoluble matter) separated in the above (measurement of the amount of mono-fatty acid, dimer acid, and trimer acid in polyamidoamine) was dehydrated using a rotary evaporator, and then neutralized with 12 g of 50% aqueous potassium hydroxide solution. Water was removed using anhydrous sodium sulfate, and the mixture was naturally filtered through 5C filter paper to prepare a sample for GC analysis. This sample was analyzed under the same conditions as in <Content of free polyamine (unreacted polyamine) in polyamidoamine>. Quantitation was performed by subtracting the petroleum ether-soluble matter (2.52 g) containing mono-fatty acid, dimer acid, and trimer acid from the polyamidoamine before decomposition (3.5 g), and the remaining 0.98 g was designated as the raw polyamine (Sample B). GC analysis detected only the raw polyamine (TETA).

[0090] <Measurement of Monomer Acid, Dimer Acid, and Trimer Acid in Dimer Acid> The amounts of monomer acid, dimer acid, and trimer acid in dimer acid were quantified. The HPLC conditions were the same as those described above (Measurement of the Amount of Mono-Fatty Acid, Dimer Acid, and Trimer Acid in Polyamidoamine), and a calibration curve was created to quantify the amounts of monomer acid, dimer acid, and trimer acid. The weight percent of monomer acid in Td216 was found to be 8 weight percent by HPLC as described above (Measurement of the Amount of Mono-Fatty Acid in Polyamidoamine). The total weight percent of dimer acid and trimer acid was 92 weight percent, and proportionally divided based on the relative area ratio of HPLC, it was found to be 79 weight percent dimer acid and 13 weight percent trimer acid. Note that under the same HPLC conditions, the relative area ratio of dimer acid and trimer acid was approximately the same as the relative weight ratio.

[0091]

[0092] The above results show that the ratio of the charged amounts and the ratio of the skeleton composition of the resulting polyamidoamine are in good agreement. Furthermore, it was found that the amount of unreacted polyamine (free polyamine) was within the margin of error.

Claims

1. A polyamidoamine obtained by reacting a polyamine with an acid component containing a mono-fatty acid and a dimer acid, wherein the mono-fatty acid comprises a hydroxyl-containing mono-fatty acid containing at least one hydroxyl group, and a non-hydroxyl-containing mono-fatty acid containing no hydroxyl groups, the polyamine comprises a polyethylene polyamine, the molar ratio of the polyamine to the dimer acid is 2.5 or more and 15 or less, and the weight ratio of the total amount of the dimer acid and the hydroxyl-containing mono-fatty acid to the non-hydroxyl-containing mono-fatty acid is 2.0 or more.

2. The polyamidoamine of claim 1, wherein the mono-fatty acid comprises ricinoleic acid.

3. A curable composition comprising the polyamidoamine of claim 1 or 2.

4. A curing agent obtained by reacting the polyamidoamine in the curable composition according to claim 3 with an epoxy resin.

5. A coating material containing the curing agent according to claim 4.

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