JP3526088B2 - Curing agent for epoxy resin - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to epoxy resins, especially
Regarding a curing agent used for curing an epoxy resin used as a paint, an adhesive, etc., more specifically, for an epoxy resin containing an organic polyamine modified by addition with a phosphoric acid compound-added epoxy compound as an active ingredient Regarding curing agents.

[0002]

BACKGROUND OF THE INVENTION An epoxy resin composition comprising an epoxy resin and a curing agent has many excellent properties such as adhesion to various substrates, heat resistance, chemical resistance, electrical properties, mechanical properties, etc. It is used in a wide range of industrial fields, especially in the field of paints and adhesives.

When used in these applications, it is used as a solvent type using various organic solvents, a solventless type not using an organic solvent, or an aqueous type in which an epoxy resin composition is dispersed in water. When these epoxy resin compositions are applied to a material in which rust has already occurred, or a material used in a wet atmosphere where rust is likely to occur, the anticorrosion performance is insufficient. In particular, when applied to steel plates that have already rusted (rust-faced steel plates), the corrosion resistance is not sufficient at all and adhesion failure occurs, so it is complicated to remove rust in advance. It was necessary to have a good surface treatment. Further, even if such a base treatment is performed, when used in an environment where rust is likely to occur, such as in a wet atmosphere, it is not possible to eliminate the drawback that the anticorrosion performance and the adhesion are deteriorated. .

For this reason, it has been attempted to maintain the anticorrosion property even when applied to a rust-faced steel sheet by giving an epoxy resin a functional group having a chelate-forming ability. JP-A-143620 proposes a reaction product of a specific diphosphonic acid and an epoxy resin, and JP-A-58-63758 discloses a coating composition containing an epoxy resin treated with a phosphoric acid compound and a curing agent for the epoxy resin. Things have been proposed.

Although the initial adhesion and corrosion resistance are improved to some extent by using the epoxy resin treated with the phosphoric acid compound as described above, the effect of long-term exposure under severe conditions is insufficient. Yes, it was not satisfactory in practice.

Therefore, an object of the present invention is to provide a curing agent for an epoxy resin composition which can form a film having good adhesion and corrosion resistance even when exposed to a harsh condition for a long time. is there.

[0007]

Means for Solving the Problems As a result of intensive studies, the inventors of the present invention have achieved the above object by using a modified compound obtained by addition-modifying an organic polyamine with a specific phosphorus-containing epoxy compound as a curing agent. We have found that it can be achieved.

The present invention has been made on the basis of the above findings. (A) Aliphatic polyamines, alicyclic polyamines,
At least one organic polyamine selected from the group consisting of aromatic polyamines and heterocyclic polyamines, and (B) (1) a phosphorus acid having at least one P-OH bond, its ester and its salt An adduct of at least one phosphoric acid compound selected from the group and (2) a polyepoxy compound having an average of more than one epoxy group in the molecule, the phosphorus-containing compound having an unreacted epoxy group in the molecule. An addition modification product with an epoxy compound is contained as an active ingredient, and the addition modification product is the above-mentioned organic polyamine
And the above phosphorus-containing epoxy compound, the above organic polyamine
The above-mentioned phosphorus-containing epoxy compound per 1 active hydrogen of the class
Of epoxy group is added at the ratio of 0.01 to 0.3
The above-mentioned phosphorus-containing epoxy compound
Is the polyepoxy compound and the phosphoric acid compound,
For one epoxy group of the above polyepoxy compound,
The number of P-OH groups in the phosphoric acid compound is 0.05 to 0.8.
The present invention provides a curing agent for an epoxy resin, which is obtained by an addition reaction at a certain ratio .

The epoxy resin curing agent of the present invention will be described in detail below.

The organic polyamines of the component (A) used as a raw material for the addition modification which is an active ingredient of the curing agent for an epoxy resin of the present invention include aliphatic polyamines, alicyclic polyamines, aromatic polyamines and It is at least one organic polyamine selected from the group consisting of heterocyclic polyamines. Examples of the organic polyamines include the followings.

The above aliphatic polyamines include ethylenediamine, 1,2-propylenediamine, 1,3-propylenediamine, 1,4-butylenediamine, hexamethylenediamine, 2,4,4-trimethylhexamethylenediamine and diethylenetriamine. , Dipropylenetriamine, triethylenetetramine, tetraethylenepentamine, dipropylenetriamine, dimethylaminopropylamine, diethylaminopropylamine and the like.

Examples of the alicyclic polyamines include menthenediamine, 1,3-bis (aminomethyl) cyclohexane, isophoronediamine, N-3-aminopropylcyclohexylamine, 1,4-diaminocyclohexane and 2,4-. Examples thereof include diaminocyclohexane, bis (aminocyclohexyl) methane, 1,3-bis (aminocyclohexylpropane), bis (3-methyl-4-aminocyclohexyl) methane and 1,4-bis (ethylamino) cyclohexane.

Examples of the aromatic polyamines include m-xylylenediamine, p-xylylenediamine and 4- (1
-Aminoethyl) aniline, metaphenylenediamine,
Diaminodiphenylmethane, diaminodiphenyl sulfone, bis (3-ethyl-4-amino-5-methylphenyl) methane, 1,4-bis (2- (3,5-dimethyl-
4-aminophenyl) propyl) benzene and the like can be mentioned.

The above heterocyclic polyamines include N
-Aminoethylpiperazine, 3,9-bis (3-aminopropyl) -2,4,8,10-tetraoxaspiro [5.5] undecane and the like can be mentioned.

The phosphorus-containing epoxy compound as the component (B) used in the present invention is used for addition-modifying the organic polyamines as the component (A) to obtain an addition-modified product (active ingredient), An adduct of a phosphoric acid compound as the (B) -component and a polyepoxy compound having an average of more than one epoxy group in the molecule as the (B) -component, wherein an unreacted epoxy group is present in the molecule. I have.

The phosphoric acid compound as the component (B) is at least one phosphoric acid compound selected from the group consisting of phosphoric acid having at least one P-OH bond, its ester and its salt, As the phosphorus acid,
Examples thereof include orthophosphoric acid, metaphosphoric acid, pyrophosphoric acid, phosphorous acid, polyphosphoric acid, phosphonic acid, methanephosphonic acid, benzenephosphonic acid, 1-hydroxyethane-1,1-diphosphonic acid and phosphinic acid. Examples of the acid ester include an alkyl, alkenyl or substituted alkyl partial ester of the above acid (as the alkyl group, methyl, ethyl, propyl, butyl, hexyl, octyl, isooctyl, 2-ethylhexyl, decyl, dodecyl, tetradecyl, octadecyl, etc. Examples of the alkenyl group include allyl, octenyl, decenyl,
Those having 1 to 30 carbon atoms such as octadecenyl are preferred, and the substituted alkyl group is 2-hydroxyethyl,
2-hydroxypropyl, 2-hydroxybutyl, 2-
Hydroxyalkyl groups such as hydroxy-2-phenylethyl; 2-hydroxy-3-methoxypropyl, 2-hydroxy-3-butoxypropyl, 2-hydroxy-3.
-Octoxypropyl, 2-hydroxy-3-octadecyloxypropyl, 2-hydroxy-3-phenoxypropyl, 2-hydroxy-3-toluoxypropyl, 2
An alkoxy or aryloxyhydroxyalkyl group such as -hydroxy-3-octylphenoxypropyl; 2
-(3-Methoxy-2-hydroxypropoxy) ethyl, 2- (3-butoxy-2-hydroxypropoxy)
Having a hydroxy group and / or an ether bond such as an alkoxy such as ethyl, 2- (3-phenoxy-2-hydroxypropoxy) ethyl, 2- (3-toluoxy-2-hydroxypropoxy) ethyl or an aryloxyhydroxyalkoxyalkyl group. Preferred are], and examples of the acid salt of phosphorus include potassium, lithium, sodium, calcium, barium and zinc salts of the above acids. Among the above phosphate compounds,
In particular, a compound having two or more P-OH bonds is preferable, and particularly, when orthophosphoric acid or phosphoric acid monoester, particularly orthophosphoric acid monoester is used, a remarkably excellent effect can be obtained, which is preferable.

Further, as the polyepoxy compound having an average of more than one epoxy group in the molecule which is the component (B), the polyepoxy compound which is usually used for the preparation of the epoxy resin composition is particularly preferable in its structure and the like. Although not limited, those having an average of more than one glycidyl group such as glycidyl ether group, glycidyl ester group, and glycidylamino group in the molecule are particularly preferable.

The polyepoxy compound having a glycidyl ether group is obtained by converting a phenolic or alcoholic hydroxyl group into a glycidyl ether by a known method, and examples thereof include resorcinol, hydroquinone,
Pyrocatechol, phloroglucinol, dihydroxynaphthalene, biphenol, methylenebisphenol (bisphenol F), methylenebis (orthocresol), ethylidenebisphenol, isopropylidenebisphenol (bisphenol A), isopropylidenebis (orthocresol), tetrabromobisphenol A, bis (Hydroxyphenyl) phenylmethane, bis (hydroxyphenyl) cyclohexylmethane, cyclohexylidene bisphenol, thiobisphenol, sulfobisphenol (bisphenol S), oxybisphenol, 1,3-bis (4-hydroxycumyl) benzene, 1 , 4-bis (4-hydroxycumyl)
Benzene, polyglycidyl ethers of mononuclear or polynuclear polyphenols such as phenol-formaldehyde condensates and ethylene glycol, propylene glycol,
Examples thereof include glycidyl ethers of polyhydric alcohols such as butylene glycol, hexanediol, polyglycol, thiodiglycol, glycerin, trimethylolpropane, pentaerythritol, sorbitol, and bisphenol A-ethylene oxide adduct, and particularly diglycidyl of alkylidene bisphenol. Ether type epoxy resins are preferred.

Examples of the polyepoxy compound having a glycidyl ester group include maleic acid, fumaric acid, itaconic acid, succinic acid, glutaric acid, suberic acid,
Adipic acid, azelaic acid, sebacic acid, dimer acid,
Trimer acid, phthalic acid, isophthalic acid, terephthalic acid,
Glycidyl esters of aliphatic, aromatic or alicyclic polybasic acids such as trimellitic acid, trimesic acid, pyromellitic acid, tetrahydrophthalic acid, hexahydrophthalic acid and endomethylenetetrahydrophthalic acid, and homopolymers of glycidyl methacrylate Alternatively, a copolymer or the like can be used.

Examples of the polyepoxy compound having a glycidylamino group include N, N-diglycidylaniline and bis (4- (N-methyl-N-glycidylamino) phenyl) methane.

In addition, as the polyepoxy compound as the component (B), epoxidized natural oils and fats such as epoxidized soybean oil, epoxidized linseed oil, epoxidized safflower oil and epoxidized tall oil, vinylcyclohexene diepoxide, Dicyclopentadiene diepoxide, 3,4-
Epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, 3,4-epoxy-6-
Methylcyclohexylmethyl-3,4-epoxy-6-
Methylcyclohexanecarboxylate, bis (3,4
-Epoxy-6-methylcyclohexylmethyl) adipate, etc. epoxidized cyclic olefin compound, epoxidized polybutadiene, epoxidized conjugated diene polymer such as epoxidized styrene-butadiene copolymer, heterocyclic compound such as triglycidyl isocyanurate, etc. Can also be used.

[0022] The (B) - (2) wherein a component of polyepoxy compound (B) - (1) the ratio of the amount of time of an addition reaction between phosphorous acid compound of the component, an epoxy group of ports Riepokishi Compound 1 The P-OH group of the phosphoric acid compound is 0.
It is 05 to 0.8 , and preferably 0.1 to 0.5. When the above ratio (P-OH group) is less than 0.05, the effect of phosphoric acid addition is difficult to appear, and the ratio is 0.8
If the number is over, the remaining epoxy groups will decrease,
Subsequent addition modification with organic polyamines tends to be difficult.

The curing agent of the present invention contains, as an active ingredient, an addition modification product of the organic polyamines of the above component (A) and the phosphorus-containing epoxy compound of the above component (B),
Addition metamorphic ratio of the hydrated phosphorous epoxy compound to the organic polyamines to the active one hydrogen of organic polyamines, epoxy group-containing phosphorus epoxy compound is 0. 01
0.3 pieces, good Mashiku is Ru Oh at a ratio to be 0.02 to 0.2 pieces. When the ratio of the above phosphorus-containing epoxy compound is less than 0.01, the effect due to the addition of phosphoric acid is difficult to manifest, and even when it exceeds 0.3, the corresponding effect cannot be obtained and it is wasteful. Not only that, since the active hydrogen equivalent becomes large, it becomes necessary to use a large amount of the curing agent of the present invention when used in an epoxy resin composition.

The above-mentioned addition modification product (organic polyamines addition-modified with a phosphorus-containing epoxy compound), which is an active ingredient of the curing agent of the present invention, can be used as it is as a curing agent, but if necessary, It is also possible to add other well-known modification treatments, for example, addition modification with the polyepoxy compound used as the component (B)-,
The Mannich modification for reacting phenols and formaldehyde, the amide modification for reacting a carboxylic acid such as dimer acid, and the Michael addition modification for adding an olefin compound such as acrylonitrile to an amino group can be performed.

There is no particular limitation on the time for carrying out the other modification treatment, and other modification treatment may be carried out prior to the addition modification by the phosphorus-containing epoxy compound according to the present invention, or by the phosphorus-containing epoxy compound according to the present invention. Other modification treatments may be carried out at the same time as the addition modification, or other modification treatments may be carried out after the addition modification by the phosphorus-containing epoxy compound according to the present invention.

A solvent may be added to the curing agent of the present invention for the purpose of decreasing the viscosity, or a surfactant may be added and dispersed in water according to the purpose of use to prepare an aqueous system. It can also be a curing agent.

The epoxy resin cured by the curing agent of the present invention is not particularly limited in its structure and the like as long as it is a compound which has an average of more than one epoxy group in the molecule which is usually used. The polyepoxy compound used as the component (B) can be used as it is.

The above epoxy resins may be used alone or in combination of two or more, and if necessary, a solvent, a monoepoxy compound or the like may be added. Further, these epoxy resins may be so-called emulsified epoxy resins which are emulsified in advance using a surfactant such as polyoxyethylene alkylphenyl ether compound.

The curing agent of the present invention is the above-mentioned epoxy resin and a reactive diluent, a non-reactive diluent, a filler, a reinforcing agent, a pigment, a dye, a solvent, a plasticizer, a leveling agent which is used as necessary. Solvent type, solventless type or aqueous type curable composition (cured epoxy resin composition) together with conventional additives such as thixotropic agent, flame retardant and release agent
Used as.

The curing agent of the present invention has a number of active hydrogens
It is preferably used in an amount of 0.9 to 1.1 per one epoxy group of the cured epoxy resin. If the number of active hydrogen is less than 0.9, uncured epoxy resin may remain, and even if it exceeds 1.1, the curing speed is not so much improved and is not only wasteful. However, since the unreacted active hydrogen remains, the water resistance of the cured film may decrease.

The curable composition thus obtained is subjected to a suitable method, for example, brush coating, roller, spray, spatula coating, press coating, doctor blade coating, electrostatic coating, electrodeposition coating,
It is used as an undercoat or intermediate coating, a filler, a sealant, a protective coating, a coating material, a sealing material, a mortar, a coating material, etc. by applying it to a substrate by a method such as dipping coating. Because of its excellent adhesion to, for example, solvent-type or solvent-free type, heavy-duty anticorrosive paint for corrosion protection of land and sea structures or structural adhesives for automobiles, iron related to building materials,
It is suitable for use as an adhesive for metals such as aluminum and stainless steel, and as a water-based type for land-based structures, especially for anticorrosion paints in closed places or condominiums where handling of hazardous materials is a problem.

[0032]

The present invention will be described in more detail with reference to production examples and usage examples. However, the present invention is not limited by the following production examples and use examples (examples). In the production examples below, the epoxy equivalent means the molecular weight of the epoxy compound (resin) per epoxy group, and the active hydrogen equivalent means 1 hydrogen atom of the amine.
It represents the molecular weight of each amine compound, and when a solvent is used, it represents the apparent molecular weight including the solvent.

Production Example 1 of Phosphorus-Containing Epoxy Compound Production Example 1 100 parts by weight of bisphenol A (BPA) -diglycidyl ether type epoxy resin (epoxy equivalent 190) and ortholine were placed in a glass flask equipped with a thermometer, a stirrer and a cooling tube. 6 parts by weight of the acid was taken and reacted at 80 ° C. for 5 hours with stirring to obtain a pale yellow liquid product (phosphorus-containing epoxy compound 1) having an epoxy equivalent of 310.

Production Example 2 100 parts by weight of a BPA-diglycidyl ether type epoxy resin (epoxy equivalent 475) and 3 parts of orthophosphoric acid were placed in a glass flask equipped with a thermometer, a stirrer and a cooling tube.
Part by weight and 55 parts by weight of xylene were taken and reacted at 80 ° C. for 5 hours with stirring to obtain a pale yellow liquid product (phosphorus-containing epoxy compound 2) having an epoxy equivalent of 1360.

Production Example 3 100 parts by weight of a BPA-diglycidyl ether type epoxy resin (epoxy equivalent 190) and 6 parts by weight of phosphoric acid monoethyl ester were placed in a glass flask equipped with a thermometer, a stirrer and a cooling tube. The reaction was carried out by stirring at 80 ° C. for 5 hours to obtain a pale yellow liquid product (phosphorus-containing epoxy compound 3) having an epoxy equivalent of 245.

Production Example 4 In a glass flask equipped with a thermometer, a stirrer and a cooling tube, 100 parts by weight of a bisphenol F-diglycidyl ether type epoxy resin (epoxy equivalent 175) and mono (3-butoxy-2-phosphate) were used. 10 parts by weight of (hydroxypropyl) ester was taken and reacted at 80 ° C. for 5 hours with stirring to obtain a pale yellow liquid product (phosphorus-containing epoxy compound 4) having an epoxy equivalent of 230.

Production Example 5 In a glass flask equipped with a thermometer, a stirrer and a condenser, 100 parts by weight of a BPA-diglycidyl ether type epoxy resin (epoxy equivalent 190) and mono (3-butoxy-2-hydroxy phosphate) were used. Propyl) ester 2
Take 0 parts by weight and stir at 80 ° C. for 5 hours to react,
A light yellow liquid product (phosphorus-containing epoxy compound 5) having an epoxy equivalent of 340 was obtained.

Production Example 6 of Curing Agent of the Present Invention Production Example 6 A glass flask equipped with a thermometer, a stirrer and a cooling tube was charged with 136 parts by weight of metaxylylenediamine and 93 parts by weight of the phosphorus-containing epoxy compound 1 and heated at 80 ° C. The reaction was carried out by stirring for 3 hours to obtain a pale yellow liquid product (curing agent 1) having an active hydrogen equivalent of 62.

Production Example 7 136 parts by weight and 140 parts by weight of metaxylylenediamine were placed in a glass flask equipped with a thermometer, a stirrer and a condenser tube.
Part by weight of the phosphorus-containing epoxy compound 1 was taken and reacted at 80 ° C. for 3 hours with stirring to obtain a pale yellow liquid product (curing agent 2) having an active hydrogen equivalent of 111.

Production Example 8 In a glass flask equipped with a thermometer, a stirrer and a cooling tube, 136 parts by weight of metaxylylenediamine, 50 parts by weight of phosphorus-containing epoxy compound 1, BPA-diglycidyl ether type epoxy resin (epoxy) were used. Equivalent 190) 50 parts by weight and xylene 118 parts by weight were taken and reacted at 80 ° C. for 3 hours with stirring to obtain a pale yellow liquid product (curing agent 3) with active hydrogen equivalent 99.

Production Example 9 136 parts by weight of metaxylylenediamine and 47 parts by weight of phenol were placed in a glass flask equipped with a thermometer, a stirrer and a cooling tube, and 41 parts by weight of 37% formalin were gradually added dropwise to 120. The mixture was stirred at 0 ° C. for 2 hours while dehydrating. Then, 50 parts by weight of the phosphorus-containing epoxy compound 1 and 102 parts by weight of xylene were taken and reacted by stirring at 80 ° C. for 3 hours to obtain a pale yellow liquid product (curing agent 4) having an active hydrogen equivalent of 102. .

Production Example 10 In a glass flask equipped with a thermometer, a stirrer and a condenser, 136 parts by weight of metaxylylenediamine and 123
Part by weight of the phosphorus-containing epoxy compound 2 was taken and reacted at 80 ° C. for 3 hours with stirring to obtain a pale yellow liquid product (curing agent 5) having an active hydrogen equivalent of 66.

Production Example 11 In a glass flask equipped with a thermometer, a stirrer and a cooling tube, 136 parts by weight of meta-xylylenediamine, 136 parts by weight of the phosphorus-containing epoxy compound 3 and 58 parts by weight of xylene were placed, and at 80 ° C. The reaction was carried out by stirring for 3 hours to obtain a pale yellow liquid product (curing agent 6) having an active hydrogen equivalent of 96.

Production Example 12 136 parts by weight of meta-xylylenediamine, 136 parts by weight of phosphorus-containing epoxy compound 4 and 58 parts by weight of xylene were placed in a glass flask equipped with a thermometer, a stirrer and a cooling tube, and the mixture was heated at 80 ° C. The reaction was carried out by stirring for 3 hours to obtain a pale yellow liquid product (curing agent 7) having an active hydrogen equivalent of 100.

Production Example 13 136 parts by weight of metaxylylenediamine and 99 parts by weight of phosphorus-containing epoxy compound 5 were placed in a glass flask equipped with a thermometer, a stirrer and a cooling tube, and the mixture was stirred at 80 ° C. for 3 hours for reaction. Thus, a pale yellow liquid product (curing agent 8) having an active hydrogen equivalent of 63 was obtained.

Production Example 14 A glass flask equipped with a thermometer, a stirrer and a cooling tube was charged with 68 parts by weight of metaxylylenediamine, 73 parts by weight of triethylenetetramine, 140 parts by weight of the phosphorus-containing epoxy compound 1 and 119 parts by weight. Take xylene, 80 ℃
The reaction was carried out by stirring for 3 hours to obtain a pale yellow liquid product (curing agent 9) having an active hydrogen equivalent of 88.

Production Example 15 In a glass flask equipped with a thermometer, a stirrer and a cooling tube, 136 parts by weight of metaxylylenediamine and BPA were added.
57 parts by weight of a diglycidyl ether type epoxy resin (epoxy equivalent 190) was taken and reacted at 80 ° C. for 3 hours while stirring to obtain a pale yellow liquid product (curing agent 10) having an active hydrogen equivalent of 52. .

Use Example 1 (Use Example as Anticorrosion Paint) A curable composition having the composition (parts by weight) shown in the following [Table 1] and [Table 2] such that the epoxy equivalent and the active hydrogen equivalent are equal. The test piece was prepared by applying the product to a rust-faced steel plate on which floating rust had been removed after being exposed outdoors for 1 year so as to have a film thickness of 150 μm, and then curing at room temperature for 1 week. Using this test piece, a salt spray test (SST) was conducted according to JIS K5400, and the surface condition was observed with time. The results are shown in [Table 1] and [Table 2] below. In the table, the results of the SST test were evaluated according to the following standard criteria. ◯: Same as initial, no abnormality. ×: Spot rust occurred.

[0049]

[Table 1]

[0050]

[Table 2]

Use Example 2 (for Adhesion) After compounding the compound shown in the following [Table 3] with the epoxy equivalent and the active hydrogen equivalent being equal to each other by kneading with a three-roll, the compound is shown in the following [Table 3]. A test piece was prepared by coating the base material and curing it at room temperature for one week. The filler calcium carbonate was used in an amount of 150% by weight with respect to the resin solid content. For this test piece, the original and 80
Tensile shearing stress was measured after immersion in warm water of ℃ for 7 days and tensile shearing stress (kgf / cm ² ). The results are shown in [Table 3] below.

[0052]

[Table 3]

From the results of the above [Table 1] to [Table 3], the following is clear. The curable composition using the curing agent of the present invention having an organic polyamine addition-modified with a phosphorus-containing epoxy compound to which a phosphoric acid compound has been added as an active ingredient, can be used for a long time even when used as a paint for rust-faced steel sheet. Shows excellent anticorrosion effect, has excellent adhesion to various metal plates, and significantly reduces adhesion strength even after immersion in warm water (Examples 1 to 14).

On the other hand, when a curable composition containing no phosphoric acid compound was used (Comparative Example 1), the anticorrosion effect was poor and rust was observed in a short period of time. Is completely insufficient, and when a phosphoric acid compound is used as the epoxy resin to be cured using a curing agent that does not use a phosphoric acid compound (Comparative Examples 2 and 3), the initial anticorrosion performance is excellent, but The effect is lost in a relatively short period of time, and when it is used as an adhesive (Comparative Examples 4 and 5), the initial adhesiveness is relatively excellent, but the adhesiveness after dipping in hot water decreases. It is remarkable, so that it is insufficient when used under severe conditions.

[0055]

The curing agent for an epoxy resin according to the present invention (claim 1) is an epoxy resin composition capable of forming a film having good adhesion and corrosion resistance even when exposed for a long time under severe conditions. Can be given. Therefore, the curing agent for an epoxy resin of the present invention (claim 1) is useful as a curing agent for an epoxy resin used in an anticorrosion paint or a metal adhesive. Further, the curing agent for an epoxy resin of the present invention (Claims 2, 3, 4) further improves the above effects.

─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Manabu Abe 8-4 Higashiohisa, Arakawa-ku, Tokyo Asahi Denka Kogyo Co., Ltd. (56) References JP-A-59-56459 (JP, A) JP-A-SHO 58-63758 (JP, A) JP-A-63-284217 (JP, A) JP-A-55-60567 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C08G 59/00 -59/72

Claims (4)

(57) [Claims] 1. (A) At least one organic polyamine selected from the group consisting of aliphatic polyamines, alicyclic polyamines, aromatic polyamines and heterocyclic polyamines, and (B) (1) P At least 1 --OH bond
At least one phosphoric acid compound selected from the group consisting of phosphorus acid having one, its ester and its salt, and (2)
An addition product of a polyepoxy compound having an average of more than one epoxy groups in the molecule, the addition modified product of the phosphorus-containing epoxy compound having an epoxy group unreacted in the molecule contains as an active ingredient, the The addition modified product is the above-mentioned organic polyamine and the above-mentioned phosphorus-containing compound.
Epoxy compound and active hydrogen of the above organic polyamines
Epoxy group of the above-mentioned phosphorus-containing epoxy compound per 1
Is added and modified at a ratio of 0.01 to 0.3
The above-mentioned phosphorus-containing epoxy compound is the above polyepoxy compound
And the above phosphoric acid compound,
P-OH group of the above-mentioned phosphoric acid compound to one poxy group
Is added and reacted at a ratio of 0.05 to 0.8
The curing agent is intended. 2. The curing agent for an epoxy resin according to claim 1, wherein the phosphoric acid compound is orthophosphoric acid. 3. The curing agent for an epoxy resin according to claim 1, wherein the phosphoric acid compound is a phosphoric acid monoester. 4. The curing agent for an epoxy resin according to claim 1, wherein the polyepoxy compound is a diglycidyl ether type epoxy resin of alkylidene bisphenol.