JP2001302769A - Urethnized ketimine hardener and hadening resin composition comprising the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a urethanized ketimine hardener useful as a hardener for an epoxy resin; and a one liquid type hardening resin composition containing the hardener. SOLUTION: The hardener can be obtained by reacting (a) a ketimine compound having one or more intermolecular secondary amino groups with (b) a compound having an isocyanate group so that the isocyanate group of the compound (b) may have an equivalent ratio (NCO/NH) of 0.8-1.20 to the secondary amino group of the compound (a).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a urethanated ketimine curing agent useful as a curing agent for an epoxy resin, and further relates to a one-pack type curable resin composition containing the curing agent.

[0002]

2. Description of the Related Art Ketimine compounds are polyamine compounds having at least one primary amino group blocked by a carbonyl compound in one molecule, and have been conventionally used as a curing agent for epoxy resins. Usually, an epoxy / amine curing system used for applications such as paints and adhesives is a two-pack type composition. By using a ketimine compound, for example, as shown in Japanese Patent Application Laid-Open No. It can be a liquid type curable composition. In this case, the dissociation of ketimine into amine is prevented by adding a dehydrating agent to remove water in the composition, or by excessively adding a ketone-based solvent, thereby ensuring storage stability.

However, if the ketimine compound has a secondary amino group or a tertiary amino group in the molecule, it reacts with the epoxy group in the composition, and if the compound has a hydroxyl group, it becomes tertiary. Since a secondary amino group acts as a reaction catalyst between the hydroxyl group and the epoxy group and storage stability becomes insufficient, it is desired to use a ketimine compound not containing these. However, in such a case, in view of the properties of the composition such as physical properties and curability, it may be necessary to select a ketimine compound having a high molecular weight by a method such as an adduct obtained by reacting an epoxy resin with the composition. there were. Even such adducts often have a secondary amino group or a tertiary amino group in the structure, and it has been difficult to obtain a one-pack composition having good storage stability.

[0004]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors reacted a ketimine compound having a secondary amino group with a compound having an isocyanate group to form a secondary amino group. The present inventors have found that by converting the group into urethan (urea), the reactivity is suppressed and the storage stability is improved, and the present invention has been completed.

That is, the present invention relates to (a) a ketimine compound having one or more secondary amino groups in a molecule, and (b) a compound having an isocyanate group in the compound (a). Urethanated ketimine curing agent which is reacted so that the equivalent ratio (NCO / NH) of the isocyanate group in compound (b) to the group is in the range of 0.8 to 1.20, and the urethanated ketimine curing agent And a curable resin composition containing the epoxy resin.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, the ketimine compound (a) has one or more secondary amino groups in the molecule, and usually has one or more primary amino groups blocked by a carbonyl compound. A compound having two or more in the molecule and having no amino group other than the secondary amino group and the blocked amino group.

The above-mentioned "primary amino group blocked by a carbonyl compound" is a protected amino group which can be easily hydrolyzed by, for example, the presence of water to replace a free primary amino group. And the following formula (I)

[0008]

Embedded image (In the formula, R ¹ represents a hydrogen atom or a monovalent hydrocarbon group such as an alkyl group or a cycloalkyl group, and R ² represents a monovalent hydrocarbon group such as an alkyl group or a cycloalkyl group.) be able to.

The ketimine compound (a) is, for example, 1
A polyamine compound having one or more secondary amino groups and two or more primary amino groups in the molecule is reacted with a carbonyl compound to block substantially all of the primary amino groups in the polyamine compound. It can be obtained by forming a protected amino group represented by the above formula (I).

The polyamine compound before blocking is as follows:
Any of an aliphatic system, an alicyclic system, and an aromatic system may be used. The polyamine compound generally has a content of about 30 to about 20.
It is advantageous to have a primary amino group equivalent in the range of 0, preferably from about 40 to about 100, and generally from about 6
Suitably it has a number average molecular weight in the range of 0-400, preferably about 80-200.

Specific examples of the above polyamine compound include:
For example, diethylenetriamine (DETA), triethyltetramine (TETA), tetraethylenepentamine (TEPA) and the like can be mentioned. Further, even polyamine compounds which do not originally have a secondary or tertiary amino group can be adducted with an epoxy resin or the like. And those having a secondary or tertiary amino group in the structure thereof. Specific examples include ethylenediamine, propylenediamine, butylenediamine, hexamethylenediamine, poly (oxypropylene) diamine, and xylylenediamine. Aliphatic, aromatic and alicyclic polyamines such as amines, diaminodiphenylmethane, phenylenediamine, isophoronediamine, and 1,3-bisaminocyclohexane, and epoxy resin adducts such as polyamidoamines and polyamide resins Or the like can be mentioned things.

Examples of the carbonyl compound used for blocking the polyamine compound include ketones such as acetone, methyl ethyl ketone, methyl isopropyl ketone, methyl isobutyl ketone, diisobutyl ketone and cyclohexanone; aldehydes such as acetaldehyde and benzaldehyde. And the like.

The polyamine compound can be converted into a ketimine by blocking with the above ketones, and can be converted into an aldimine by blocking with the above aldehydes. The ketimine compound (a) in the present invention includes both ketiminated and aldiminated compounds.

The reaction between the polyamine compound and the carbonyl compound can be carried out by a method known per se, wherein substantially all the primary amino groups present in the polyamine compound are replaced with the carbonyl compound. The reaction is carried out in such a quantitative ratio and reaction conditions as to react. In order to facilitate the reaction (dehydration reaction), it is generally advantageous to use ketones having poor water solubility and small steric hindrance such as methyl isobutyl ketone and methyl ethyl ketone as the carbonyl compound.

In the present invention, the compound (b) having an isocyanate group may be, for example, tolylene diisocyanate, xylylene diisocyanate, phenylene diisocyanate.
G, diphenylmethane diisocyanate, bis (isocyanate methyl) cyclohexane, tetramethylene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, methylene diisocyanate, isophorone Aromatic, alicyclic or aliphatic polyisocyanate compounds such as diisocyanate, and isocyanurates of these polyisocyanate compounds
And uret-forms, excess amounts of these polyisocyanate compounds, ethylene glycol, propylene glycol, trimethylolpropane, hexanetriol,
Castor oil, terminal isocyanate obtained by reacting a low molecular active hydrogen-containing compound such as diglyceride or a high molecular active hydrogen-containing compound such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polylactone diol, polyester polyol or polycarbonate polyol. A monoisocyanate compound such as a compound obtained by reacting phosgene with a phthalic acid-containing compound, lysine triisocyanate, an aliphatic or aromatic monoamine, or a compound obtained by reacting a hydroxyl group-containing compound with one of the isocyanate groups of the diisocyanate compound; Isocyanate, ethyl isocyanate, propyl isocyanate, additive TI (Sumitomo Bayer Urethane Co., Ltd.)
Monoisocyanate compound (trade name, product name).

In the present invention, the ketimine compound (a) and the compound (b) having an isocyanate group are used in an equivalent ratio of an isocyanate group in the compound (b) to a secondary amino group in the compound (a) ( NCO / NH) is 0.8 to
The reaction is carried out so as to be in the range of 1.20, preferably 0.90 to 1.05, to obtain a urethanated ketimine curing agent.

When the ketimine compound (a) is reacted with the compound (c) having an isocyanate group, depending on the degree of progress of the reaction, for example, when the viscosity of the reaction system increases and exceeds the appropriate range, alcohols, The reaction can be controlled by adding appropriate amounts of phenols, lactams, oximes and the like.

The reaction between the ketimine compound (a) and the compound (c) having an isocyanate group is usually carried out at room temperature to 7
The reaction can be carried out at 0 ° C. for about 0.5 to 3 hours, if necessary, in the presence of a reaction catalyst. Examples of the reaction catalyst include dibutyltin bis (acetylacetonate), dibutyltin diacetate, dibutyltin di (2-ethylhexylate), dibenzyltin di (2-ethylhexylate), dibutyltin dilaurate, dibutyltin Organic metal compounds such as diisooctyl maleate and tetrabutyl titanate are exemplified.

The urethane-containing ketimine curing agent of the present invention obtained as described above is useful as a curing agent for an epoxy resin, and can impart good storage stability to a one-part composition.

The present invention also comprises an epoxy resin (A) and a urethanated ketimine curing agent (B), wherein the urethanated ketimine curing agent of the present invention is used as the urethanated ketimine curing agent (B). A curable resin composition is provided.

The epoxy resin (A) is a resin having two or more epoxy groups in one molecule, preferably 2 to 5 on average, and having a number average molecular weight of about 350 to 2000, preferably about 500 to 1000. Epoxy resins within the range and having an epoxy equivalent in the range of about 80-1000, preferably about 150-800.

As the epoxy resin (A), for example, glycidyl ether type epoxy resin, glycidyl ester type epoxy resin, other glycidyl ether type epoxy resin, alicyclic epoxy resin; these epoxy resins are selected from alkylphenol and fatty acid. And a modified epoxy resin modified with at least one type of modifier, an alkylphenol or an alkylphenol novolak type resin obtained by reacting an alkylphenol or an alkylphenol novolak type resin with epichlorohydrin.

The glycidyl ether type epoxy resin is, for example, an epoxy resin having a glycidyl ether group which can be obtained by reacting a polyhydric alcohol, a polyhydric phenol or the like with epihalohydrin or alkylene oxide. Examples of the polyhydric alcohol include ethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, neopentyl glycol, butylene glycol, hexanediol,
Glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, diglycerin, sorbitol and the like can be mentioned. Examples of the polyhydric phenol include 2,2-bis (4-hydroxyphenyl) propane [bisphenol A], 2,2-bis (2-hydroxyphenyl) propane, and 2- (2-hydroxyphenyl) 2 -(4-hydroxyphenyl) propane, halogenated bisphenol A, bis (4-hydroxyphenyl) methane [bisphenol F], tris (4-hydroxyphenyl) propane, resorcinol, tetrahydroxyphenylethane, 1,2,3-tris (2,3-epoxypropoxy) propane, novolak-type polyhydric phenol, cresol-type polyhydric phenol and the like can be mentioned.

Examples of the glycidyl ester type epoxy resin include diglycidyl phthalate, diglycidyl hexahydrophthalate, diglycidyl tetrahydrophthalate, and diglycidyl dimer.

Other glycidyl type epoxy resins include, for example, tetraglycidylaminodiphenylmethane, triglycidyl isocyanurate and the like.

As the alicyclic epoxy resin, (3,4-
Epoxy-6-methylcyclohexyl) methyl-3,4
-Epoxy-6-methylcyclohexanecarboxylate, (3,4-epoxycyclohexyl) methyl-3,
4-epoxycyclohexanecarboxylate, bis (3,4-epoxycyclohexylmethyl) adipate, bis (3,4-epoxy-6-methylcyclohexylmethyl) adipate, Eporide GT300 (trade name, manufactured by Daicel Chemical Industries, Ltd.), 3 Functional alicyclic epoxy resin), Eporide GT400 (Daicel Chemical Industries, Ltd.)
Made, trade name, 4-functional alicyclic epoxy resin), EHPE
(Manufactured by Daicel Chemical Industries, Ltd., trade name, polyfunctional alicyclic epoxy resin).

The modified epoxy resin is a glycidyl ether type epoxy resin, a glycidyl ester type epoxy resin, another glycidyl ether type epoxy resin or an epoxy resin before modification, which is an alicyclic epoxy resin, at least one selected from alkylphenols and fatty acids. It is an epoxy resin modified by a kind of modifier. The epoxy resin before modification preferably has an epoxy equivalent of about 250 or less on average.

As the alkylphenol which can be used as the above modifier, a phenol having an alkyl group having about 2 to 18 carbon atoms is preferable.
Examples thereof include butylphenol, paraoctylphenol, and nonylphenol. In addition, as the fatty acid that can be used as the denaturing agent, a drying oil fatty acid and a semi-dry oil fatty acid are preferable. Specific examples thereof include linseed oil fatty acid, safflower oil fatty acid, soybean oil fatty acid, sesame oil fatty acid, eno oil fatty acid, and hemp oil. Fatty acids, grape kernel oil fatty acids,
Krill oil fatty acid, corn oil fatty acid, sunflower oil fatty acid, cottonseed oil fatty acid, walnut oil fatty acid, rubber seed oil fatty acid,
Deer oil fatty acids, fish oil fatty acids, high diene fatty acids,
Tall oil fatty acids and dehydrated castor oil fatty acids can be mentioned. The above modifiers, alkylphenols and fatty acids, can be used alone or in combination of two or more.

The modified epoxy resin is prepared by mixing the unmodified epoxy resin with a modifier, which is an alkylphenol and / or a fatty acid, in the presence of a catalyst, if necessary, for 100 to 20 times.
It can be obtained by heating to 0 ° C. The reaction between the epoxy resin and the modifying agent before the modification is based on the fact that the equivalent ratio of the equivalent of the epoxy group in the epoxy resin to the total equivalent of the hydroxyl group in the alkylphenol and the carboxyl group of the fatty acid is 1 in the former: latter ratio. : It is preferable to mix and react so as to be in the range of 0.2 to 0.6.

The mixing ratio of the epoxy resin (A) and the urethane-containing ketimine curing agent (B) is such that the carbonyl compound of the urethane-containing ketimine curing agent (B) is based on 1 equivalent of the epoxy group in the epoxy resin (A). The total amount of active hydrogen bonded to the amino group of the polyamine compound which has been eliminated to form a primary amino group is 0.4 to 3.0 equivalents, preferably 0.6 to 3.0 equivalents.
It is desirable to use a ratio of 2.0 equivalents from the viewpoints of curability, non-adhesion, and corrosion resistance of the coating film.

The composition of the present invention contains an epoxy resin (A) and a urethanated ketimine curing agent (B) as essential components, and if necessary, further comprises a dehydrating agent; an organic solvent; Metal powders such as zinc powder and aluminum powder; pigments such as coloring pigments, extender pigments and rust-preventive pigments; and additives such as thickeners, plasticizers, fillers and dispersants.

As the above-mentioned dehydrating agent, a dehydrating agent known per se can be used, and representative examples thereof include the following.

Powdery and porous metal oxide or carbonized material; for example, synthetic silica, activated alumina, zeolite, activated carbon, etc., calcium having a composition such as CaSO ₄ , CaSO ₄ .1 / 2H ₂ O, CaO, etc. Compounds; for example, calcined gypsum, soluble gypsum, quicklime, etc. Metal alkoxides; for example, aluminum isopropylate, aluminum sec-butyrate, tetraisopropyl titanate, tetra n-butyl titanate, zirconium 2-propylate, zirconium n-butyrate, ethyl Organic alkoxy compounds such as silicate and vinyltrimethoxysilane; monofunctional isocyanates such as methyl orthoformate, ethyl orthoformate, and dimethoxypropane; monomethyl isocyanates such as methyl isocyanate, ethyl isocyanate Luisocyanate, Additive TI (Sumitomo Bayer Urethane Co., Ltd.)
Product name). The above-mentioned diisocyanates can also be used.

These dehydrating agents can be used alone or in combination of two or more. The amount of the dehydrating agent used depends on the amount of water contained in the coating composition and the absorption of the dehydrating agent, the adsorptive capacity or the reactivity with water, but in general, from the viewpoint of storage stability and coating film performance, etc. Is suitably in the range of 0.2 to 25% by weight, preferably 0.5 to 15% by weight, based on the weight of the composition.

[0035]

The present invention will be described in more detail with reference to the following Examples and Comparative Examples. In Examples, "parts" and "%" indicate "parts by weight" and "% by weight" unless otherwise specified.

Production Example 1 of Urethaneated Ketimine Curing Agent A diethylenetriamine 103 was placed in a reaction vessel equipped with a thermometer, a thermostat, a stirrer, a reflux condenser and a dropping device.
0 parts and 2400 parts of methyl isobutyl ketone, and while blowing nitrogen gas, 105-1
The mixture was heated to 50 ° C. to advance the condensation reaction. When the amount of condensed water generated reached 35% of the charged amount of diethylenetriamine, the reaction was terminated, and 3070 parts of a diethylenetriamine ketimine compound solution (A) having a nonvolatile content of 86.9% was added. Obtained. The active hydrogen equivalent of the ketimine compound solution (A) was 66.8.
(Solid content).

To 614 parts of the ketimine compound solution (A), 168 parts of hexamethylene diisocyanate was further added dropwise over 10 minutes. At that time, the temperature in the mixture was 6
The temperature was adjusted to 0 ° C. or lower, and the reaction was carried out at 60 ° C. for about 1 hour to obtain a urethane-containing ketimine curing agent having a nonvolatile content of 89.7%. The active hydrogen equivalent of the urethane-containing ketimine curing agent was 87.8 (solid content).

Examples 2 to 5 and Comparative Examples 1 and 2 Each urethane compound was prepared in the same manner as in Example 1 except that the ketimine compound solution (A) and the isocyanate compound had the composition shown in Table 1. Ketimine curing agent ~
And got. The nonvolatile content and the active hydrogen equivalent are as shown in Table 1. Note that (Note 1) and (Note 2) in the table are as follows. "Duranate TSS-10
0 ": Asahi Kasei Corporation, trade name, isocyanurate form of hexamethylene diisocyanate, 2-3-functional type (Note 2)" Additive TI ": Sumitomo Bayer Urethane Co., Ltd., trade name, paratoluenesulfonyl isocyanate Example 6 A reaction vessel equipped with a thermometer, a thermostat, a stirrer, a reflux condenser, and a dropping device was charged with 150 parts of methyl isobutyl ketone as a solvent, and further charged with 400 parts of polyethylene glycol (average molecular weight: 400) and heated to 80 ° C. After the temperature was raised, 444 parts of isophorone diisocyanate was added dropwise at the same temperature over 30 minutes. 8 after dropping
The temperature was kept at 0 ° C., and when the isocyanate value became 100 (solid content) or less, it was cooled to 40 ° C. To this, 614 parts of the ketimine compound solution (A) obtained in Example 1 was dropped over 10 minutes. At that time, the temperature in the mixture was adjusted to 60 ° C. or lower, and the reaction was maintained at 60 ° C. for about 1 hour to obtain a urethane-containing ketimine curing agent having a nonvolatile content of 85.7%. The active hydrogen equivalent of the urethane-containing ketimine curing agent was 172 (solid content).

Comparative Example 3 Ketimine compound solution (A) 61 obtained in the same manner as in Example 1.
In 4 parts, mixed solvent ("Epomarine thinner 20",
266 parts of Kansai Paint Co., Ltd. (trade name) and 572 parts of a 90% solution of "Epicoat 828" (epoxy resin, epoxy resin, epoxy equivalent: 193) are gradually stirred at room temperature (20 ° C.). Was added. that time,
The temperature in the mixture is adjusted to 60 ° C. or less,
The reaction was carried out at 60 ° C. for a time to obtain a ketimine curing agent having an epoxy resin adduct and a non-volatile content of 72.2%. The active hydrogen equivalent of the epoxy resin adducted ketimine curing agent was 131 (solid content).

[0040]

[Table 1]

Preparation of Curable Resin Compositions Examples 7 to 19 and Comparative Examples 4 to 9 100 parts of the epoxy resin solutions shown in Tables 2 and 3 were placed in a 1-liter container, and methyl orthoformate was prepared. Ketimine curing agents were added in the proportions shown in Tables 2 and 3 and mixed and stirred to obtain each curable resin composition. Each of the obtained curable resin compositions was subjected to the following performance tests. The results are shown in Tables 4 and 5. Note that (Note 3) to (Note 5) in the table are as follows. (Note 3) “Epicoat 1001”: Yuka Shell Epoxy Co., Ltd., epoxy resin, epoxy equivalent 488, 70% of which
Used as a solution (Note 4) "Epicoat 828": manufactured by Yuka Shell Epoxy Co., Ltd., epoxy resin, epoxy equivalent 193, used as a 90% solution of this. (Note 5) "Haripol EP-450": manufactured by Harima Chemicals, alkylphenol modified. Epoxy resin, epoxy equivalent 680, 60% aliphatic hydrocarbon solvent solution (Performance test) (* 1) Storage stability: Take about 250 g of each curable resin composition in a 250 ml tin container (round can), and cover. After closing for one month in a constant temperature room at 40 ° C., the state change of the liquid was examined.

：: No abnormality Δ: Viscosity increased greatly ×: Gelation (* 2) Curability: Each curable resin composition was applied to a degreased polished steel plate with a doctor blade to a dry film thickness of 60 ±. 10 μm
And dried by leaving it in a constant temperature room at 20 ° C. for 24 hours to prepare each coated plate.
-5400 Evaluated according to the evaluation criteria of 6.5.

：: cured △: semi-cured ×: uncured (* 3) Finishing property: each curable resin composition was applied to a degreased polished steel plate with a doctor blade to a dry film thickness of 60 ± 10 μm.
m and left in a constant temperature room at 20 ° C. for 7 days to dry them to prepare each coated plate.
It was evaluated according to the evaluation standard of K-5400 7.1.

：: No abnormality Δ: Generation of shrinkage (* 4) Adhesion: For each coated plate prepared in the same manner as in (* 3), 25 square grids of 2 mm width and 25 squares according to JIS K-5400 8.5.1. Create an eye and measure its adhesion
The evaluation was performed according to the evaluation criteria of IS K-5400 8.5.1.

：: 10 to 8 points Δ: 7 to 5 points (* 5) Breaking strength and elongation: Each curable resin composition
100 ± dry film thickness on a tin plate with a doctor blade
It was applied to a thickness of 20 μm, left in a constant temperature room at 20 ° C. for 7 days, and dried to prepare each coated plate. The coated film was isolated by a mercury amalgam method and used as a sample having a length of 20 mm and a width of 5 mm. Using a universal tensile tester (manufactured by Shimadzu Corporation), the film was pulled at a speed of 4 mm per minute at a temperature of 20 ° C., and the strength (kgf / cm ² ) and elongation (%) when the coating film was cut were examined.

[0046]

According to the present invention, a ketimine compound having a secondary amino group is reacted with a compound having an isocyanate group, and the secondary amino group is urethanized (ureaized), whereby the reactivity thereof is increased. Is obtained, the urethane-containing ketimine curing agent is useful as a curing agent for an epoxy resin, and a curable resin composition containing the epoxy resin and the curing agent can be very one-part. It has excellent storage stability.

[0047]

[Table 2]

[0048]

[Table 3]

[0049]

[Table 4]

[0050]

[Table 5]

Continued on the front page F term (reference) 4J036 AA01 AB01 AB02 AB03 AB07 AB10 AC05 AC08 AD08 AD09 AF06 AF08 AG04 AG06 AG07 AH05 AJ18 CA07 CA16 DC27 DC28 FA03 FA04 FA05 FA06 FA10 JA01 JA06

Claims (2)

[Claims] 1. A method according to claim 1, wherein (a) a ketimine compound having at least one secondary amino group in the molecule, and (b) a compound having an isocyanate group, with respect to the secondary amino group in the compound (a). (B) isocyanate group equivalent ratio (N
(CO / NH) in the range of 0.8 to 1.20. 2. An epoxy resin, (B) (a) a ketimine compound having one or more secondary amino groups in the molecule, and (b) a compound having an isocyanate group in the molecule (a). Compound (b) for a secondary amino group in
The equivalent ratio of isocyanate groups in the solution (NCO / NH) is 0.
A curable resin composition containing a urethane-containing ketimine curing agent, which is reacted so as to be in the range of 8 to 1.20.