JP5447090B2 - Epoxy resin composition and cured product thereof - Google Patents

Description

  The present invention relates to a polyamidoamine curing agent that is soluble in a solvent containing an aliphatic hydrocarbon as a main component and that is excellent in workability, adhesion, and corrosion resistance, an epoxy resin composition using the same, and a cured product thereof.

  Compositions containing amine curing agents and epoxy resins are used to coat and surface metal and inorganic substrates, as adhesives and sealants, as matrix resins, as tool material resins, or very generally as molded Widely used in industry as a casting resin for manufacturing articles or sheet-like structures. Examples of the amine-based curing agent used include aliphatic polyamines, alicyclic polyamines, aromatic polyamines, and polyamide amines.

  Among amine-based curing agents, polyamide amine generally has a high viscosity, and an epoxy resin composition containing polyamide amine cannot be said to have good workability. However, the cured product of the epoxy resin composition is excellent in adhesion to metals and inorganic substrates and anticorrosive properties, and also has an advantage that the cured product has less curing shrinkage because of its good flexibility.

  As a polyamidoamine from which an epoxy resin composition excellent in workability can be obtained and a composition capable of obtaining a cured product excellent in strength can be obtained, for example, 1: 0.2 to 1.5 per equivalent of aromatic monocarboxylic acid. Equivalents of an aliphatic monocarboxylic acid, 1: 0.1 to 0.6 equivalents of monocarboxylic acid per equivalent of aromatic dicarboxylic acid, and 0.8 to 1.3: 1 moles of polyamine per equivalent of total acid. A polyamidoamine obtained by reacting at a ratio is disclosed (for example, see Patent Document 1).

  Patent Document 1 discloses the polyamidoamine curing agent as a curing agent having a low viscosity. However, since the curing agent is obtained by using dicarboxylic acid, the molecular weight is increased, and as a result, a lower viscosity is required, such as an adhesive for injection and paint used for repairing bridges, although the viscosity is low. Cannot satisfy the demands in the field.

  In addition, the amine curing agent and the epoxy resin are usually prepared by dissolving the amine curing agent and the epoxy resin in an organic solvent. However, the above amine-based curing agents and epoxy resins are generally poor in solvent solubility, and low flash point, low boiling point, highly toxic solvents such as toluene, xylene, methyl ethyl ketone, and ethyl acetate must be used. No. Therefore, there is a problem that the odor is strong and the working environment is not good.

As a resin composition excellent in solvent solubility in an aliphatic hydrocarbon-based organic solvent that has little odor and hardly pollutes the work environment, such as mineral spirits, for example, an aliphatic hydrocarbon group having 4 to 18 carbon atoms on an aromatic nucleus A resin composition containing a novolak-type epoxy resin as a substituent and a polyamide resin is disclosed (for example, see Patent Document 2). However, the resin composition disclosed in Patent Document 2 has a high viscosity of the curing agent (polyamidoamine) used, and it is necessary to dilute with a large amount of organic solvent in order to obtain a resin composition having a low viscosity and easy to apply. It was difficult to obtain a resin composition having an increased solid content.

JP2000-226437 (2nd page) JP-A-9-12678 (2nd page)

  An object of the present invention is to provide a polyamidoamine curing agent that is soluble in a solvent mainly composed of aliphatic hydrocarbons and has excellent workability, adhesion, and corrosion resistance, an epoxy resin composition using the same, and a cured product thereof. There is.

  As a result of intensive studies, the present inventors have used aliphatic monocarboxylic acid in a large amount beyond the range described in Patent Document 1 in obtaining a polyamidoamine curing agent. A polyamidoamine curing agent having a low viscosity can be obtained by using a carboxylic acid and an aliphatic monocarboxylic acid in a molar ratio of 1: 2 to 1: 6 exceeding the range described in the cited document 1, and the polyamidoamine. The hardener has good solubility in weak solvents mainly composed of aliphatic hydrocarbons such as mineral spirits. By using this polyamidoamine in combination with an alkylphenol-modified epoxy resin, workability, adhesion, and corrosion resistance are improved. The inventors have found that an excellent epoxy resin composition can be obtained, and have completed the present invention.

  That is, the present invention is a polyamidoamine curing agent obtained by reacting a polyethylene polyamine (a1), an aliphatic monocarboxylic acid (a2) and an aromatic monocarboxylic acid (a3). ) And aromatic monocarboxylic acid (a3) in a molar ratio [(a2) / (a3)] of 2/1 to 6/1, a polyamidoamine curing agent (A) obtained by using carbon atoms An epoxy resin composition comprising a novolac type epoxy resin (B) having an aliphatic hydrocarbon group of 4 to 18 as a substituent on the aromatic nucleus and an aliphatic hydrocarbon organic solvent (C) It provides things.

  Moreover, this invention provides the hardened | cured material characterized by hardening the said epoxy resin composition.

ADVANTAGE OF THE INVENTION According to this invention, the epoxy resin composition which is soluble in the solvent which has an aliphatic hydrocarbon as a main component, is low viscosity, and is excellent in workability | operativity, and its hardened | cured material can be provided. Since the epoxy resin composition of the present invention is a composition dissolved in a solvent mainly composed of aliphatic hydrocarbons, the composition is used as a repair coating on a substrate on which a coating film has already been formed. Even if it is repeatedly applied on the coating film, the old coating film is less likely to cause lifting. Therefore, the epoxy resin composition of the present invention is particularly useful for coating applications.

  The present invention is described in detail below. The polyamidoamine curing agent of the present invention is a polyamidoamine curing agent obtained by reacting a polyethylene polyamine (a1), an aliphatic monocarboxylic acid (a2) and an aromatic monocarboxylic acid (a3). It is obtained by using (a2) and aromatic monocarboxylic acid (a3) in a molar ratio [(a2) / (a3)] of 2/1 to 6/1. When the aliphatic monocarboxylic acid (a2) and the aromatic monocarboxylic acid (a3) are reacted so that the molar ratio [(a2) / (a3)] is smaller than 2, the strength of the resulting cured product is sufficient. It is not preferable because it is not a hardener. An epoxy-based resin composition having a low viscosity when the aliphatic monocarboxylic acid (a2) and the aromatic monocarboxylic acid (a3) are reacted so that the molar ratio [(a2) / (a3)] is larger than 6. It is not preferable because it is difficult to obtain. The polyamidoamine curing agent of the present invention provides an epoxy resin composition having a low viscosity, and since the cured product of the composition has a high strength, the aliphatic monocarboxylic acid (a2) and the aromatic monocarboxylic acid are used. A polyamidoamine curing agent obtained by using the acid (a3) in a molar ratio [(a2) / (a3)] of 3/1 to 5/1 is more preferable.

As the polyethylene polyamine (a1) used in the present invention, for example, a polyethylene polyamine represented by the following formula can be preferably used.
NH ₂ (C ₂ H ₄ NH) _n H (1)
[N is 1 or more. ]

  Examples of the polyethylene polyamine (a1) include ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, hexaethyleneheptamine, heptaethyleneoctamine, octaethylenenonamine, and nonaethylenedecamine.

  Examples of the polyethylene polyamine (a1) include piperazine and N-aminoalkylpiperazine having an alkyl chain having 2 to 6 carbon atoms.

Among the polyethylene polyamines (a1) used in the present invention, a polyamidopolyamine curing agent in which n in the formula (1) is 4 to 8 is preferable, and tetraethylenepentamine is more preferable because a polyamide polyamine curing agent that is difficult to increase in viscosity is obtained. . Furthermore, hexaethyleneheptamine is more preferable because a polyamidoamine curing agent with less odor can be obtained.

  Examples of the aliphatic monocarboxylic acid (a2) used in the present invention include monocarboxylic acids having 18 to 50 carbon atoms. Examples of the monocarboxylic acid include linoleic acid, stearic acid, oleic acid, linolenic acid, and the like. Examples of the natural fatty acid containing these include tall oil fatty acid, soybean oil fatty acid, linseed oil fatty acid, tung oil fatty acid, castor oil fatty acid, coconut oil fatty acid, safflower oil fatty acid and the like.

  The aliphatic monocarboxylic acid (a2) is preferably an aliphatic monocarboxylic acid having 18 to 36 carbon atoms because it can prevent the polyamidoamine curing agent obtained after the reaction from increasing in viscosity. Aliphatic monocarboxylic acids are more preferred. Further, the aliphatic monocarboxylic acid (a2) is particularly preferably a tall oil fatty acid mainly composed of oleic acid and linoleic acid.

Aromatic monocarboxylic acids for use in the present invention (a3) comprises at least one carboxylic acid group one benzene ring, a compound a carboxylic acid group is directly bonded to the benzene ring. When the acid contains two benzene rings, they may be bonded directly to each other or may be bonded through a short linking group such as an oxygen atom or a methylene group. Aromatic monocarboxylic acids include, for example, benzoic acid, salicylic acid, naphthoic acid, and one or two alkyl chains on the aromatic ring, where the alkyl chain is alkyl-substituted having from 1 to about 4 carbon atoms. And various benzoic acids and naphthoic acids. The aromatic monocarboxylic acid (a3) is preferably benzoic acid because an epoxy resin composition having an excellent balance between viscosity and cured product strength can be obtained.

  The polyamidoamine curing agent of the present invention includes, for example, polyethylene polyamine (a1), aliphatic monocarboxylic acid (a2) and aromatic monocarboxylic acid (a3), aliphatic monocarboxylic acid (a2) and aromatic monocarboxylic acid. The acid (a3) can be prepared by charging the reaction system in a molar ratio [(a2) / (a3)] of 2/1 to 6/1, followed by dehydration condensation at a high temperature of 200 ° C. or higher.

The reaction ratio of the polyethylene polyamine (a1), the aliphatic monocarboxylic acid (a2), and the aromatic monocarboxylic acid (a3) is the same as the amino group (NH ₂ ) in the polyethylene polyamine (a1) and the aliphatic monocarboxylic acid ( a2) and the carboxyl group (COOH) in the aromatic monocarboxylic acid (a3) are 2.0 / 1.5 to 2.0 / 0.5 in an equivalent ratio [(NH ₂ ) / (COOH)]. The reaction is preferably performed because the active hydrogen equivalent is easily adjusted, and more preferably 2.0 / 1.2 to 2.0 / 0.7.

  The active hydrogen equivalent of the polyamidoamine curing agent of the present invention is preferably 50 to 100, because it is easy to adjust the blending amount with the epoxy resin (B) which is the main component of the epoxy resin composition of the present invention described later, and is preferably 60 to 90 is more preferred. Moreover, 400-800 are preferable for the polyamidoamine hardening | curing agent of this invention that an appropriate reaction with the epoxy resin (B) which is a main ingredient advances, and 500-700 are more preferable.

  In obtaining the polyamidoamine curing agent of the present invention, a polyamine other than the polyethylene polyamine (a1), a fatty acid other than the aliphatic monocarboxylic acid (a2) and the aromatic monocarboxylic acid (a3) as long as the effects of the present invention are not impaired. May be used in combination.

  Examples of the polyamine other than the polyethylene polyamine (a1) include methylene diamine, ethylene diamine, 1,2-diaminopropane, 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, and 1,6. -Diaminohexane, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, etc., benzylamine, diethylenetriamine, dipropylenetriamine, triethylenetetramine, tripropylenetetramine, tetra Ethylenepentamine, tetrapropylenepentamine, pentaethylenehexamine, nonaethylenedecane, trimethylhexamethylenediamine, tetra (aminomethyl) methane, tetrakis (2-aminoethylaminomethyl) methane, , 3-bis (2′-aminoethylamino) propane, triethylene-bis (trimethylene) hexamine, bis (3-aminoethyl) amine, bishexamethylenetriamine, 1,4-cyclohexanediamine, 4,4′- Methylenebiscyclohexylamine, 4,4'-isopropylidenebiscyclohexylamine, norbornadiamine, bis (aminomethyl) cyclohexane, diaminodicyclohexylmethane, isophoronediamine, mensendiamine, etc., bis (aminoalkyl) benzene, bis (aminoalkyl) ) Naphthalene, bis (cyanoethyl) diethylenetriamine, orthoxylylenediamine, metaxylylenediamine, paraxylylenediamine, phenylenediamine, naphthylenediamine, diaminodiphenylmethane, di Minodiethylphenylmethane, 2,2-bis (4-aminophenyl) propane, 4,4'-diaminodiphenyl ether, 4,4'-diaminobenzophenone, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfone 2,2′-dimethyl-4,4′-diaminodiphenylmethane, 2,4′-diaminobiphenyl, 2,3′-dimethyl-4,4′-diaminobiphenyl, 3,3′-dimethoxy-4,4 ′ -Diaminobiphenyl, bis (aminomethyl) naphthalene, bis (aminoethyl) naphthalene, etc., N-methylpiperazine, morpholine, 1,4-bis- (8-aminopropyl) -piperazine, piperazine-1,4-diazacyclo Heptane, 1- (2′-aminoethylpiperazine), 1- [2 ′-(2 ″ -aminoethyl) Tilamino) ethyl] piperazine, tricyclodecanediamine and the like.

  Examples of fatty acids other than the aliphatic monocarboxylic acid (a2) and aromatic monocarboxylic acid (a3) include trimer acid, which is a trimer of parimitic acid, stearic acid, and natural fatty acids.

  The epoxy resin composition of the present invention may be abbreviated as the polyamidoamine curing agent of the present invention [hereinafter referred to as polyamidoamine curing agent (A). And an epoxy resin (B).

The novolac type epoxy resin (B) having an aliphatic hydrocarbon group having 4 to 18 carbon atoms as a substituent on the aromatic nucleus used in the present invention is not particularly limited in structure, but for example, a phenol nucleus Examples thereof include those having a structure obtained by reacting a phenol novolac resin having an aliphatic hydrocarbon group as a substituent with epihalohydrin.

  Such a novolak type epoxy resin (B) having an aliphatic hydrocarbon group having 4 to 18 carbon atoms as a substituent on the aromatic nucleus can be produced, for example, by the following method.

That is, there can be mentioned a method in which phenols having an aliphatic hydrocarbon group as a substituent on the aromatic nucleus and formaldehyde or paraformaldehyde are condensed in the presence of a catalyst, and the resulting phenol novolac resin is reacted with epihalohydrin.

  Examples of phenols having an aliphatic hydrocarbon group as a substituent on the aromatic nucleus used here include alkylphenols such as butylphenol, hexylphenol, octylphenol, nonylphenol, dodecylphenol, and octadecylphenol. Moreover, in this invention, the said phenols may be used individually by 1 type, and may use 2 or more types together. Further, the position and number of the aliphatic hydrocarbon substituent may be arbitrary.

Examples of the catalyst used for the reaction of phenols having an aliphatic hydrocarbon group as a substituent on the aromatic nucleus and ketones include formic acid, acetic acid, propionic acid, hydrochloric acid, sulfuric acid, phosphoric acid, salicylic acid, benzoic acid, Examples include acidic catalysts such as oxalic acid.

  Here, as a result of the reaction of phenols having an aliphatic hydrocarbon group as a substituent on the aromatic nucleus and ketones, the resulting phenol novolac resin has an appropriate viscosity in the solution of the epoxy resin finally obtained. In order to maintain the average number of aromatic nuclei, those having an average nucleus number of 2-6 nuclei are preferable, and those having 2-4 nuclei are particularly preferable.

  Next, the resulting phenol novolac resin is reacted with epihalohydrin to glycidylate and the desired novolak epoxy resin (B) having an aliphatic hydrocarbon group having 4 to 18 carbon atoms as a substituent on the aromatic nucleus is obtained. can get.

  The reaction conditions in this case are not particularly limited, but, for example, 1.4 to 20 equivalents of epihalohydrin are added to 1 equivalent of the hydroxyl group of the phenol novolak resin, and 50 to 120 ° C. in the presence of a base. It is preferable to carry out the reaction.

  The base used in the glycidylation is not particularly limited, and examples thereof include potassium hydroxide, sodium hydroxide, barium hydroxide, magnesium oxide, sodium carbonate, potassium carbonate, etc., preferably potassium hydroxide and / or Sodium hydroxide is mentioned.

  Although it does not specifically limit as an epihalohydrin concerning this invention, Preferably, epichlorohydrin, (beta) -methylepichlorohydrin, epibromohydrin, (beta) -methylepibromohydrin etc. are mentioned, Especially, epichlorohydrin is preferable from a reactive point.

  The novolak type epoxy resin (B) thus obtained is a novolak type epoxy resin having an aliphatic hydrocarbon group having 4 to 18 carbon atoms as a substituent on the aromatic nucleus as described above. Here, the novolac type epoxy resin (B) is preferably one having an average number of nuclei of aromatic nuclei of 2 to 6 nuclei, particularly preferably 2 to 4 nuclei from the viewpoint of the effect of reducing the viscosity of the composition. .

  In addition, the aliphatic hydrocarbon group present on the aromatic nucleus in the epoxy resin (B) has 4 to 18 carbon atoms as described above. Among them, the number of carbon atoms from the viewpoint of good heat resistance. It is especially preferable that it is 6-10.

  The blending ratio of the polyamidoamine curing agent (A) and the epoxy resin (B) in the epoxy resin composition of the present invention is not particularly limited as long as the blending ratio does not impair the effects of the present invention. Although not usually, the equivalent ratio of active hydrogen in the total amount of the curing agent to the epoxy group in the epoxy resin composition is in the range of 0.5 to 1.5, and the mechanical strength of the resulting cured product is The ratio is preferably in the range of 0.7 to 1.2 from the viewpoint that the cured product is excellent in transparency and excellent in transparency.

  Examples of the aliphatic hydrocarbon organic solvent used as the component (C) in the resin composition of the present invention include alkanes such as hexane, heptane, octane, decane, and dodecane, cycloalkanes such as cyclohexane and decalin, or the like. Examples thereof include organic spirits such as mineral spirits as a main component, No. 0 solvent (manufactured by Nippon Oil Co., Ltd., aromatic component 0.0% solvent: boiling point 244 to 262 ° C., flash point 133 ° C.).

  Among these, those having a flash point of 70 ° C. or more and less than 200 ° C. are preferable from the point that the flash point is high and the coating environment is good. Specifically, the No. 0 solvent is mentioned, and it is used as a paint for repair. Mineral spirit is preferable because the effect of preventing coating film defects such as lifting is good.

  The content of the aliphatic hydrocarbon-based organic solvent (C) is not particularly limited, but rather can be set to a desired solid content because it has excellent compatibility. As a thing, it is preferable that it is 50 to 90 weight% of the non volatile matter in a composition from the point of coating workability | operativity.

  The epoxy resin composition of the present invention includes a curing agent other than the polyamidoamine curing agent (A), an epoxy resin other than the novolak epoxy resin (B), and the aliphatic hydrocarbon as long as the effects of the present invention are not impaired. An organic solvent other than the organic solvent (C) may be contained.

  Examples of the curing agent other than the polyamidoamine curing agent (A) include ethylenediamine, tetramethylenediamine, hexamethylenediamine, diethylenetriamine, iminobispropylamine, bis (hexamethylene) triamine, triethylenetetramine, tetraethylenepentamine. , Pentaethylenehexamine, benzylamine, 1,3,6-trisaminomethylhexane, pendylethylenediamine, trimethylhexamethylenediamine, dimethylaminopropylamine, diethylaminopropylamine, aminoethylethanolamine, diethylene glycol / bispropylenediamine, mensen Diamine, norbornanediamine, N-aminoethylbiperazine, diaminodicyclohexylmethane, bis (4-amino-3-methyl Chloroyl) methane, 1,3-bis (aminomethyl) cyclohexane, 3,9-bis (3-aminopropyl) -2,4,8,10-tetraoxaspiro [5,5] undecane, tricyclodecanediamine, These may be added and modified by an unsaturated compound such as an epoxy compound, acrylonitrile, or an acrylate, and may be used alone or as a mixture of two or more.

  Examples of the epoxy resin other than the novolac type epoxy resin (B) include bisphenol A type epoxy resin, bisphenol F type epoxy resin, and novolac type epoxy resin other than the novolac type epoxy resin (B). It is not limited.

  Examples of organic solvents other than the aliphatic hydrocarbon organic solvent (C) include aromatic hydrocarbons such as toluene, ketones such as methyl ethyl ketone, alcohols such as isobutanol, and esters such as butyl cellosolve. Is mentioned.

  The epoxy resin composition of the present invention can further contain a reactive diluent. Examples of reactive diluents include alkyl glycidyl ethers such as phenyl glycidyl ether and butyl glycidyl ether, versatic acid glycidyl ester, α-olefin epoxide, 1,6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, Examples thereof include alkylphenol glycidyl ethers such as trimethylolpropane triglycidyl ether, methylphenol glycidyl ether, ethylphenol glycidyl ether, and propylphenol glycidyl ether, and these may be used alone or in combination of two or more.

  Among these reactive diluents, those containing an epoxy group are preferable. Further, the alkylphenol glycidyl ether has a low viscosity and can exert a diluting effect, so that the composition can be highly solidified (that is, in the composition). This is preferable because the solid content concentration is high, the solvent content is low, and the coating film can be thickened with a small number of coatings.

  In addition, additives and the like can be blended in the epoxy resin composition of the present invention depending on the intended use and the intended physical properties. Examples of the additive include curing accelerators, plasticizers, dyes, pigments, antioxidants, ultraviolet absorbers, light stabilizers, flame retardants, fillers, leveling agents, antifoaming agents, and anti-sagging agents. The applied amount is not particularly limited as long as it does not adversely affect the predetermined effect of the present invention, and is applied within a desired range.

  Examples of the curing accelerator include bisphenol A, bisphenol F, phenol, phenols such as alkylphenol having an alkyl chain having 16 or less carbon atoms, triphenyl phosphite, diphenyl hydrogen phosphite, diphenyl monodecyl phosphite and the like. Examples include phosphorous acid phenyl esters, polyhydric alcohols such as trimethylolpropane and glycerin, 2,4,6-tris (dimethylaminomethyl) phenol, butyric acid, and cellulose acetate.

  Examples of the plasticizer include polybasic acid esters such as dioctyl phthalate, dibutyl phthalate and dioctyl adipate, polyhydric alcohol esters such as diethylene glycol dibenzoate, diethylene glycol dioctate and glycerol tributyrate, Examples include epoxidized esters such as octyl 10-epoxystearate, epoxidized vegetable oil, and dioctyl 4,5-epoxyhexahydrophthalate, and phosphate esters such as triphenyl phosphate, trioctyl phosphate, and diphenyl monoisopropyl phosphate.

  Examples of the dye and pigment include titanium oxide, carbon black, iron oxide, yellow lead, disazo yellow, quinophthalone yellow, monoazo red, benzimidazoline red, and phthalocyanine blue.

  Examples of the antioxidant include hindered phenol antioxidants such as dibutylhydroxytoluene; sulfur antioxidants such as dilauryl thiodipropionate and 2-mercaptobenzimidazole; tridecyl phosphite and trilauryl triti Phosphites such as phosphite are mentioned.

Examples of the ultraviolet absorber include benzotriazole compounds such as 2- (2 -hydroxy-5′-methylphenyl) benzotriazole, benzophenone compounds such as 2,4-dihydroxybenzophenone, and salicylate esters such as phenyl salicylate. Compounds and the like.

  Examples of the light stabilizer include hindered amine compounds such as bis (2,2,6,6-tetramethyl-4-piperidyl) sepacate.

  Examples of the flame retardant include antimony trioxide, chlorinated paraffin, chlorinated diphenyl, and phosphate esters.

  Examples of the filler include metal powder such as zinc powder and aluminum break, lead oxide, calcium carbonate, hydrated alumina, barium carbonate, kaolin, silica powder, talc, barium sulfate, diatomaceous earth, wollastonite, and glass beads. , Glass micropaloon, glass fiber, organic fiber, polymer particles, hydrous aluminum potassium silicate, metal oxide-coated mica, and the like.

  Examples of the leveling agent and antifoaming agent include isoparaffin, liquid paraffin, silicon oil, polysiloxane oligomers, fluorine compounds, copolymers of acrylic acid esters and vinyl compounds, and the like.

  Examples of the anti-sagging agent include colloidal shear force, hydrogenated castor oil-based wax, polyethylene wax, amide wax, organic pentonite, aluminum stearate, and zinc stearate.

  The epoxy resin composition of the present invention can be used in various fields including adhesives, paints, linings and flooring materials. For example, it is used for the manufacture of tools as a molded product (casting resin). Also used for coating on various types of substrates such as wood, wood fiber materials (wood sealing), natural or synthetic fabrics, plastics, glass, ceramics, concrete, fiber boards and artificial stones, and metals be able to. These paints can be applied by brushing, spraying, dipping or the like. Furthermore, it can also be used as an adhesive, putty, and laminating resin. When the epoxy resin composition of the present invention is a solventless system, curing occurs at -10 ° C to + 50 ° C, preferably 0 ° C to 40 ° C. For example, a cured product having excellent strength can be obtained at a temperature as low as about 5 ° C. after 8 to 24 hours at 90% relative humidity in the atmosphere or after 1 to 4 hours at room temperature.

  Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. In the following, all parts and% are based on mass unless otherwise specified.

Synthesis Example 1 [Synthesis of Polyamidoamine Curing Agent (A)]
Tetraethylenepentamine (TEPA) 100 g, tall oil fatty acid (TOFA) 110 g (0.38 mol), benzoic acid 12 g (0.1 mol) in a 2 L container equipped with a thermometer, a stirrer and a condenser tube for dehydration condensation. In addition, the temperature was raised to 150 ° C. with stirring. It was held at 150 ° C. for 1 hour, then heated to 260 ° C. over 3 hours, and held at 260 ° C. for 5 hours. Thereafter, the produced water was distilled off to obtain a target polyamidoamine resin (A1) having an active hydrogen equivalent of 77 and a viscosity (B-type rotational viscometer, hereinafter the same) of 300 mPa · s. The molecular weight of tall oil fatty acid was 290 (the same applies hereinafter).

Synthesis example 2 (same as above)
Tetraethylenepentamine (TEPA) 100 g, tall oil fatty acid (TOFA) 64 g (0.22 mol), benzoic acid 12 g (0.1 mol) in a 2 L container equipped with a thermometer, a stirrer and a condenser tube for dehydration condensation. In addition, the temperature was raised to 150 ° C. with stirring. It was held at 150 ° C. for 1 hour, then heated to 260 ° C. over 3 hours, and held at 260 ° C. for 5 hours. Thereafter, the produced water was distilled off to obtain a target polyamidoamine resin (A2) having an active hydrogen equivalent of 56 and a viscosity of 200 mPa · s.

Synthesis example 3 (same as above)
Tetraethylenepentamine (TEPA) 100 g, tall oil fatty acid (TOFA) 168 g (0.58 mol), benzoic acid 12 g (0.1 mol) in a 2 L container equipped with a thermometer, a stirrer and a condenser tube for dehydration condensation. In addition, the temperature was raised to 150 ° C. with stirring. It was held at 150 ° C. for 1 hour, then heated to 260 ° C. over 3 hours, and held at 260 ° C. for 5 hours. Thereafter, the produced water was distilled off to obtain a target polyamidoamine resin (A3) having an active hydrogen equivalent of 148 and a viscosity of 1000 mPa · s.

Synthesis example 4 (same as above)
To a 2 L vessel equipped with a thermometer, a stirrer and a condenser tube for dehydration condensation was added 100 g of hexaethyleneheptamine, 73 g (0.25 mol) of tall oil fatty acid (TOFA), and 8 g (0.066 mol) of benzoic acid and stirred. The temperature was raised to 150 ° C. It was held at 150 ° C. for 1 hour, then heated to 260 ° C. over 3 hours, and held at 260 ° C. for 5 hours. Thereafter, the produced water was distilled off to obtain a target polyamidoamine resin (A4) having an active hydrogen equivalent of 70 and a viscosity of 500 mPa · s.

Synthesis Example 5 [Synthesis of Comparative Curing Amine Curing Agent (a)]
In a 2 L vessel equipped with a thermometer, a stirrer and a condenser tube for dehydration condensation, aminoethylpiperazine (AEP) 47 g , tetraethylenepentamine (TEPA) 352 g , tall oil fatty acid (TOFA) 461 g , benzoic acid 76 g , 64 g of terephthalic acid was added and the temperature was raised to 150 ° C. with stirring. The temperature was maintained at 150 ° C. for 1 hour, heated to 260 ° C. over 3 hours, and then maintained for 5 hours. Thereafter, the produced water was distilled off to obtain a comparative polyamidoamine resin (a1) having an active hydrogen equivalent weight of 115 and a viscosity of 970 mPa · s.

Synthesis example 6 (same as above)
In a 2 L vessel equipped with a thermometer, a stirrer and a condenser tube for dehydration condensation, aminoethylpiperazine (AEP) 62 g , triethylenetetramine (TETA) 464 g and benzoic acid 474 g were added, and the temperature was raised to 150 ° C. with stirring. . The temperature was maintained at 150 ° C. for 1 hour, heated to 260 ° C. over 3 hours, and then maintained for 5 hours. Thereafter, the produced water was distilled off to obtain a target polyamidoamine resin (a2) for comparison and having an active hydrogen equivalent of 111 and a viscosity of 18000 mPa · s.

Synthesis Example 8 [Preparation of Novolac Type Epoxy Resin (B)]
Thermometer, suitable funnel, a cooling tube, a 2 liter flask equipped with a stirrer, a para-octylphenol 400g melted, oxalic acid 35 g were charged, stirred, dissolved, from then suitable funnel, 41% formalin 80g Was kept at 100 ° C. over 3 hours. Stirring was continued for 2 hours after the completion of the proper condition to complete the reaction. Thereafter, the temperature was gradually raised to 140 ° C., and methanol and water were distilled off. Furthermore, while continuing to raise the temperature, the low-boiling substances were finally distilled off at 220 ° C. and 5 mmHg to obtain 405 g of novolak resin. The obtained novolak resin had a hydroxyl group equivalent of 214, an average number of nuclei of 3.0, and a softening point of 87 ° C.

Thermometer, suitable funnel, condenser, stirrer, equipped with a baffle plate, a 2-liter separable flask equipped with separated cock in the lower part, the novolac resin 400 g, epichlorohydrin 600g charged, stirred, and dissolved, 45 Heated to ° C. Thereafter, 400 g of a 20% aqueous sodium hydroxide solution was appropriately reduced over 3 hours from an appropriate funnel. Stirring was continued for 30 minutes after completion of the proper condition to complete the reaction. Thereafter, the stirring was stopped and the mixture was allowed to stand, and the lower layer saline was separated and removed. Next, excess epichlorohydrin and water were recovered by distillation. The obtained crude resin was dissolved with 800 g of methyl isobutyl ketone, 60 g of an aqueous sodium hydroxide solution was added, and the mixture was stirred at 80 ° C. for 3 hours. Thereafter, the salt and alkali produced by washing with water were separated into oil and water, removed, and after dehydration and filtration, methyl isobutyl ketone was recovered by distillation to obtain an epoxy resin (B1). The epoxy equivalent of the obtained epoxy resin (B1) was 350, the average number of nuclei was 3.3, and the softening point was 62 ° C.

Synthesis example 9 (same as above)
Thermometer, suitable funnel, a cooling tube, a 2 liter flask equipped with a stirrer, a para-dodecyl phenol 510g melted, charged oxalic acid 35 g, stirred, dissolved, from then suitable funnel, 41% formalin While maintaining 80 g at 100 ° C., the temperature was lowered over 3 hours. Stirring was continued for 2 hours after the completion of the proper condition to complete the reaction. Thereafter, the temperature was gradually raised to 140 ° C., and methanol and water were distilled off. Furthermore, while continuing to raise the temperature, the low-boiling substances were finally distilled off at 220 ° C. and 5 mmHg to obtain a novolak resin. The obtained novolak resin had a hydroxyl group equivalent of 275 and an average number of nuclei of 3.1.

Thermometer, suitable funnel, condenser, stirrer, equipped with a baffle plate, a 2-liter separable flask equipped with separated cock in the lower part, the novolac resin 510 g, epichlorohydrin 600g charged, stirred, and dissolved, 45 Heated to ° C. Thereafter, 400 g of a 20% aqueous sodium hydroxide solution was appropriately reduced over 3 hours from an appropriate funnel. Stirring was continued for 30 minutes after completion of the proper condition to complete the reaction. Thereafter, the stirring was stopped and the mixture was allowed to stand, and the lower layer saline was separated and removed. Next, excess epichlorohydrin and water were recovered by distillation. The obtained crude resin was dissolved with 800 g of methyl isobutyl ketone, 60 g of an aqueous sodium hydroxide solution was added, and the mixture was stirred at 80 ° C. for 3 hours. Thereafter, the salt and alkali produced by washing with water were separated into oil and water, removed, and after dehydration and filtration, methyl isobutyl ketone was recovered by distillation to obtain an epoxy resin (B2). The epoxy equivalent of the obtained epoxy resin (B2) was 450, the average number of nuclei was 3.2, and the softening point was 42 ° C.

Synthesis example 10 (same as above)
Thermometer, suitable funnel, a cooling tube, a 2 liter flask equipped with a stirrer, to melt the ortho secondary butyl phenol 290 g, was charged oxalic acid 35 g, stirred, dissolved, from then suitable funnel, 41% formalin While maintaining 80 g at 100 ° C., the temperature was lowered over 3 hours. Stirring was continued for 2 hours after the completion of the proper condition to complete the reaction. Thereafter, the temperature was gradually raised to 140 ° C., and methanol and water were distilled off. Furthermore, while continuing to raise the temperature, the low-boiling substances were finally distilled off at 220 ° C. and 5 mmHg to obtain a novolak resin. The obtained novolak resin had a hydroxyl group equivalent of 165 and an average number of nuclei of 2.9.

Thermometer, suitable funnel, condenser, stirrer, equipped with a baffle plate, a 2-liter separable flask equipped with separated cock in the lower part, the novolac resin 310 g, epichlorohydrin 600g charged, stirred, and dissolved, 45 Heated to ° C. Thereafter, 400 g of a 20% aqueous sodium hydroxide solution was appropriately reduced over 3 hours from an appropriate funnel. Stirring was continued for 30 minutes after completion of the proper condition to complete the reaction. Thereafter, the stirring was stopped and the mixture was allowed to stand, and the lower layer saline was separated and removed. Next, excess epichlorohydrin and water were recovered by distillation. The obtained crude resin was dissolved with 800 g of methyl isobutyl ketone, 60 g of an aqueous sodium hydroxide solution was added, and the mixture was stirred at 80 ° C. for 3 hours. Thereafter, the salt and alkali produced by washing with water were separated from oil and water, removed, and after dehydration and filtration, methyl isobutyl ketone was recovered by distillation to obtain an epoxy resin (B3). The epoxy equivalent of the obtained epoxy resin (B3) was 280, the average number of nuclei was 3.3, and the softening point was 67 ° C.

Test Examples 1-6
Polyamidoamine (A1) ~ tolerance to mineral spirits (A 4) and the control for polyamidoamine (a1) ~ (a2) was evaluated according to the following conditions. The evaluation results are shown in Table 1.

<Evaluation method of tolerance to mineral spirit>
Mineral spirit was added to 5 parts each of polyamidoamines (A1) to (A3) and comparative polyamidoamines (a1) to (a3) in an environment at 25 ° C. The weight of the solvent required for white turbidity was determined and calculated according to the following formula.

  Tolerance = (Weight of mineral spirit required for cloudiness / 5) x 100

  In Table 1, when it was not clouded even if mineral spirit was added until tolerance = 1000, it was indicated as 1000 ↑.

Examples 1-6 and Comparative Examples 1-6
Polyamide amine curing agent (A), comparative polyamidoamine curing agent (a), novolac type epoxy resin (B) and aliphatic hydrocarbon organic solvent (C) are blended in the formulations shown in Table 2 and Table 3. Then, the epoxy resin composition (1) [epoxy resin varnish (1)] to (6) and the comparative epoxy resin composition (1 ′) [epoxy resin varnish (1 ′)] to (6 ′) of the present invention. Was prepared. The tolerance of the obtained epoxy resin varnish (1) was evaluated, and the evaluation results are shown in Table 2.

Examples 7-12 and Comparative Examples 7-12
According to the formulation shown in Table 4 and Table 5, the epoxy resin compositions (1-1) to (6-1) and comparative epoxy resins (1′-1) to (6′-1) of the present invention are obtained. It was. The adhesion of the resulting composition to the substrate of the cured coating, the corrosion resistance of the coating, and the top coatability are evaluated according to the following evaluation methods, and the evaluation results are shown in Tables 4 and 5.

<Measurement method of adhesion>
An epoxy resin composition was applied to a mild steel sheet to a dry film thickness of 100 μm, dried at 20 ° C. for 7 days, and subjected to a cross cellophane tape test (2 mm interval 25 eyes).
○: 25/25 (number of remaining eyes / number of test eyes)
Δ: 13-25 / 25
X: 0 to 12/25

<Measurement method for corrosion resistance>
An epoxy resin composition was applied to a sandblasted plate to a dry film thickness of 100 μm, dried at 20 ° C. for 7 days, and a salt spray test (300 hours) in accordance with JIS K5400-7,8.
did.
○: No abnormality △: Some blistering and rusting ×: Significant blistering and rusting

<Measurement method of top coatability>
The epoxy resin composition was applied onto a chlorinated rubber-based old coating film (exposed for one year), and the surface state after 5 hours was visually observed.
○: No abnormality ×: Old paint film is lifting

Claims (12)

A polyamidoamine curing agent obtained by reacting a raw material consisting only of a polyethylene polyamine (a1), an aliphatic monocarboxylic acid (a2) and an aromatic monocarboxylic acid (a3). The aliphatic monocarboxylic acid (a2) and an aromatic A polyamidoamine curing agent (A) obtained by using a group monocarboxylic acid (a3) in a molar ratio [(a2) / (a3)] of 2/1 to 6/1, and 4 to 4 carbon atoms. An epoxy resin composition comprising a novolac type epoxy resin (B) having 18 aliphatic hydrocarbon groups as substituents on an aromatic nucleus and an aliphatic hydrocarbon organic solvent (C). Claims obtained by using the aliphatic monocarboxylic acid (a2) and the aromatic monocarboxylic acid (a3) in a molar ratio [(a 2 ) / (a 3 )] of 3/1 to 5/1. Item 2. An epoxy resin composition according to Item 1.   The epoxy resin composition according to claim 1, wherein the aliphatic monocarboxylic acid (a2) is tall oil fatty acid and the aromatic monocarboxylic acid (a3) is benzoic acid.   The epoxy resin composition according to claim 3, wherein the polyethylene polyamine (a1) is tetraethylenepentamine.   The epoxy resin composition according to claim 3, wherein the polyethylene polyamine (a1) is hexaethyleneheptamine.   2. The novolac type epoxy resin (B) having an aliphatic hydrocarbon group having 4 to 18 carbon atoms as a substituent on an aromatic nucleus is one having an average nucleus number of 2 to 6 aromatic nuclei. Epoxy resin composition.   The epoxy resin composition according to claim 1, wherein the aliphatic hydrocarbon organic solvent (C) is an aliphatic hydrocarbon organic solvent having 6 to 16 carbon atoms.   The epoxy resin composition according to claim 1, wherein the aliphatic hydrocarbon organic solvent (C) has a flash point of 70 ° C or higher and lower than 200 ° C. The epoxy resin composition according to claim 8, wherein the aliphatic hydrocarbon organic solvent (C) is mineral spirit.   The epoxy resin composition according to any one of claims 1 to 9, wherein the content of the hydrocarbon-based organic solvent (C) is 50 to 90% by weight of the nonvolatile content. The epoxy resin composition according to any one of claims 1 to 10, which is used for a paint. Hardened | cured material formed by hardening | curing the epoxy resin composition of any one of Claims 1-11.