JP2620233B2 - Curable epoxy blocked urethane composition - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a curable epoxy blocked urethane composition.

Further, the present invention relates to a one-part heat-curable epoxy-blocked urethane composition which has excellent storage stability and can be cured at a relatively low temperature in a short time.

Furthermore, the present invention relates to a curable epoxy-blocked urethane composition capable of providing a cured product having excellent mechanical strength, adhesiveness and rubbery elasticity.

[Conventional technology]

Conventionally, the emergence of a one-pack type latent curing type epoxy resin composition as a structural adhesive has been desired, and a method using an imidazole compound or a salt obtained by reacting an imidazole compound with an acid as a curing agent has been provided. .

However, such conventional one-part type curable epoxy resin compositions have insufficient potential and the curing reaction proceeds gradually even at room temperature, and the storage stability is still unsatisfactory. Was only about 10-20 days. In addition, cured products are also various flexible epoxy resins,
For example, even if NBP-modified epoxy and conventional urethane-modified epoxy resin were used, sufficient flexibility, rubber-like elasticity, and high peel strength could not be obtained. Furthermore, the conventional one-part curable epoxy resin composition requires a high temperature and a long time to cure, for example, a cured product having satisfactory physical properties cannot be obtained unless cured at 150 to 200 ° C. for several hours, When cured at a relatively low temperature for a short period of time, there is a drawback that the peel strength and rubbery elasticity are particularly poor.

Therefore, there has been a demand for a new one-part curable epoxy resin composition free from such disadvantages.

As a proposal for improving the above-mentioned problems, a flexible epoxy resin is used as a main agent in Japanese Patent Application No. 61-110100, an epoxy resin is adducted to isophoronediamine as a curing agent, and masked with a phenol resin. One-part curable epoxy resin compositions have been proposed.

[Problems to be solved by the invention]

However, the above-mentioned curing system has improved storage stability, short-time curing at a relatively low temperature and flexibility of a cured product as compared with a conventional one-part epoxy curing system, but has a rubber-like elasticity. A cured product having the following formula (1) cannot be obtained, and the problem inherent in epoxy resins, that is, the loss of flexibility particularly in the low-temperature region, has not been improved.

[Means for solving the problem]

Therefore, the present inventors have conducted intensive studies and found that, by using a blocked isocyanate compound in combination with a normal epoxy resin and using a carboxylic acid dihydrazide compound as a latent crosslinking agent, the storage stability is excellent and even at a relatively low temperature. It can be cured in a short time, and the cured product is a rubber-like elasticity, in particular, excellent in elasticity and flexibility at low temperature, and excellent in adhesiveness, particularly in peel strength, is obtained as a one-part curable epoxy blocked urethane resin composition. Heading, the present invention has been reached.

That is, the one-part curable epoxy-blocked urethane composition of the present invention is obtained from an epoxy resin (I) having an average of more than one adjacent epoxy group in a molecule, a polyhydroxy compound and an excess of a polyisocyanate compound. Urethane polymer having an isocyanate group content of 1 to 10% by weight having an average of more than one isocyanate group in the molecule to be obtained and an average molecular weight of 600 to 20,000 (II-
a) a compound having a phenolic hydroxyl group (II-b)
And the blocked isocyanate compound (II) obtained by masking with an NCO / phenolic hydroxyl equivalent ratio of 1 / 1.0 to 1 / 2.0
And carboxylic acid dihydrazide compound (III) as essential components.

Preferred examples of the epoxy resin (I) include those represented by the formula: (Where Z is a hydrogen atom, a methyl group or an ethyl group). An epoxy resin having an average of more than one substituted or unsubstituted glycidyl ether group represented by the formula (I-
1), Formula: (Where Z is a hydrogen atom, a methyl group or an ethyl group). An epoxy resin having an average of more than one substituted or unsubstituted glycidyl ester group represented by the formula (I-
2), Formula: (Where Z is a hydrogen atom, a methyl group, or an ethyl group). An epoxy resin (I-3) having an average of more than one N-substituted or unsubstituted 1,2-epoxypropyl group in the molecule represented by included. Particularly preferred epoxy resin (I) is an epoxy resin having an epoxy equivalent of 180 to 500.

The epoxy resin (I-1) having more than one substituted or unsubstituted glycidyl ether group in the molecule is an epoxy resin in which a phenolic hydroxy group is glycidyl-etherified and an epoxy resin in which an alcoholic hydroxyl group is glycidyl-etherified. Preferred examples of the epoxy resin (I-1) include polyglycidyl ethers (I-1-1) of polyhydric phenols having one or more aromatic nuclei and one or two polyphenols. The polyglycidyl ether (I-1-2) of an alcoholic polyhydroxyl compound derived by the addition reaction of the above polyhydric phenol having an aromatic nucleus and an alkylene oxide having 2 to 4 carbon atoms is exemplified.

Thus, the polyglycidyl ether (I-1-1) refers to a polyhydric phenol (A) having at least one aromatic nucleus and an epihalohydrin (b), for example, a basic catalyst or a basic compound such as sodium hydroxide. An epoxy resin containing a polyglycidyl ether as a main reaction product as obtained by reacting in the presence of a reaction amount of
A polyhalohydrin ether obtained by reacting a polyhydric phenol (A) having at least one aromatic nucleus with epihalohydrin (b) in the presence of an acidic catalyst such as boron trifluoride in a conventional manner; An epoxy resin obtained by reacting with a basic compound such as sodium oxide or a polyhydric phenol (A) having at least one aromatic nucleus and epihalohydrin (b) in the presence of a catalytic amount of a basic catalyst such as triethylamine And an epoxy resin obtained by reacting a polyhalohydrin ether obtained by a conventional method with a basic compound such as sodium hydroxide.

Similarly, the polyglycidyl ether (I-1-2) is, for example, a polyhydroxyl compound derived by an addition reaction of a polyhydric phenol having at least one aromatic nucleus with an alkylene oxide having 2 to 4 carbon atoms ( B) and epihalohydrin (b) are reacted by a conventional method in the presence of a catalytic amount of an acidic catalyst such as boron trifluoride to react a polyhalohydrin ether obtained with a basic compound such as sodium hydroxide. It is an epoxy resin containing polyglycidyl ether as a main reaction product as obtained at least.

Here, the polyhydric phenol (A) having at least one aromatic nucleus includes a mononuclear polyhydric phenol (A-1) having one aromatic nucleus and a polynuclear polyphenol having two or more aromatic nuclei. There is a multivalent phenol (A-2).

Examples of such mononuclear polyhydric phenol (A-1) include:
For example, resorcinol, hydroquinone, pyrocatechol, phloroglucinol, 1,5-dihydroxyl naphthalene, 2,7-dihydroxyl naphthalene, 2,6-dihydroxy naphthalene and the like can be mentioned.

Examples of polynuclear polyphenols (A-2) include:
General formula: (In the formula, Ar is an aromatic divalent hydrocarbon such as a naphthylene group and a phenylene group, and is preferably a phenylene group for the purpose of the present invention. Y ′ and Y ₁ may be the same or different, and may be a methyl group, n- Propyl group, n-butyl group, n-hexyl group,
Alkyl groups such as n-octyl, preferably alkyl having up to 4 carbon atoms or halogens, i.e. chlorine, bromine, iodine or fluorine, or methoxy, methoxymethyl, ethoxy, ethoxyethyl. , N-butoxy and amyloxy groups, preferably alkoxy groups having at most 4 carbon atoms. When a substituent other than a hydroxyl group is present in either or both of the aromatic divalent hydrocarbon groups, these substituents may be the same or different. m and z are integers having values from 0 (zero) to the maximum value corresponding to the number of hydrogen atoms of the aromatic ring (Ar) that can be substituted by the substituent, and can be the same or different values. R ₁ is for example —O—, —S—, —SO—, —SO ₂ —, or an alkylene group such as a methylene group, an ethylene group, a trimethylene group, a tetramethylene group, a pentamethylene group, a hexamethylene group,
2-ethylhexamethylene group, octamethylene group, nonamethylene group, decamethylene group or alkylidene group such as ethylidene group, propylidene group, isopropylidene group, isobutylidene group, amyliden group, isoamylidene group, 1-phenylethylidene group or cycloaliphatic group 1,4-cyclohexylene group, 1,3-cyclohexylene group, cyclohexylidene group, halogenated alkylene group, halogenated alkylidene group, halogenated cycloaliphatic group, alkoxy- and aryloxy- Substituted alkylidene group or alkoxy- and aryloxy-substituted alkylene group or alkoxy- and aryloxy-substituted cycloaliphatic group such as methoxymethylene group, ethoxymethylene group, ethoxyethylene , 2-ethoxy trimethylene group, 3-ethoxy pentamethylene group, 1,4 (2-methoxy-cyclohexane) group, phenoxy ethylene group, 2-
Phenoxytrimethylene group, 1,3- (2-phenoxycyclohexane) group or alkylene group such as phenylethylene group, 2-phenyltrimethylene group, 1-phenylpentamethylene group, 2-phenyldecamethylene group or aromatic such as phenylene group , A naphthylene group or a halogenated aromatic group such as a 1,4- (2-chlorophenylene) group, a 1,4- (2-bromophenylene) group, a 1,4- (2
-Fluorophenylene) group or an aromatic group substituted with alkoxy and aryloxy, such as 1,4- (2-methoxyphenylene) group and 1,4- (2-ethoxyphenylene)
Group, 1,4- (2-n-propoxyphenylene) group, 1,4-
A (2-phenoxyphenylene) group or an alkyl-substituted aromatic group such as 1,4- (2-methylphenylene)
Group, 1,4- (2-ethylphenylene) group, 1,4- (2-n
-Propylphenylene) group, 1,4- (2-n-butylphenylene) group, 1,4- (2-n-dodecylphenylene)
A divalent group such as a divalent hydrocarbon group such as a group, or
R ₁ is for example the formula Or a ring fused to one of the Ar groups as in the case of the compound represented by the formula, or R ₁ is a polyethoxy group, a polypropoxy group, a polythioethoxy group, a polybutoxy group, a polyphenylethoxy group. also be a polyalkoxy group such as, or R ₁ may be a group containing for example polydimethylsiloxy groups, poly diphenyl siloxy group, the such a silicon atom of polymethyl phenyl siloxy group, or R ₁ is An aromatic ring, a tertiary-amino group ether bond, which can be two or more alkylene or alkylidene groups separated by a carbonyl group or a sulfur-containing bond such as sulfur or a sulfoxide) There are dihydric phenols.

Particularly preferred among such polynuclear dihydric phenols are those represented by the general formula (Wherein Y ′ and Y ₁ have the same meanings as above, m and z have a value of 0 to 4, and R ₁ is preferably an alkylene group or an alkylidene group having 1 to 3 carbon atoms or a compound of the formula A polynuclear dihydric phenol represented by the formula:

Examples of such dihydric phenols are 2,2-bis- (p-hydroxyphenyl) -propane, 2,4'-dihydroxydiphenylmethane, bis- (2-hydroxyphenyl) -methane, commonly referred to as bisphenol A. , Bis- (4-hydroxyphenyl) -methane, bis- (4
-Hydroxy-2,6-dimethyl-3-methoxyphenyl) -methane, 1,1-bis- (4-hydroxyphenyl) -ethane, 1,2-bis- (4-hydroxyphenyl) -ethane, 1,1 -Bis- (4-hydroxy-2-chlorophenyl) -ethane, 1,1-bis- (3,5-dimethyl-4-hydroxyphenyl) -ethane, 1,3-bis-
(3-methyl-4-hydroxyphenyl) -propane,
2,2-bis- (3,5-dichloro-4-hydroxyphenyl) -propane, 2,2-bis- (3-phenyl-4-hydroxyphenyl) -propane, 2,2-bis- (3-isopropyl -4-hydroxyphenyl) -propane, 2,
2-bis- (2-isopropyl-4-hydroxyphenyl) -propane, 2,2-bis- (4-hydroxynaphthyl) -propane, 2,2-bis- (4-hydroxyphenyl) -pentane, 3,3 -Bis- (4-hydroxyphenyl) -pentane, 2,2-bis- (4-hydroxyphenyl) -heptane, bis- (4-hydroxyphenyl)-
Methane, bis- (4-hydroxyphenyl) -cyclohexylmethane, 1,2-bis- (4-hydroxyphenyl) -1,2-bis- (phenyl) -propane, 2,2-bis- (4-hydroxyphenyl ) Bis- (4-hydroxyphenyl) alkanes such as 1-phenylpropane or dihydroxybiphenyl or bis- such as 4,4'-dihydroxyphenyl, 2,2'-dihydroxybiphenyl, 2,4'-dihydroxybiphenyl (4-hydroxyphenyl) -sulfone, 2,4'-dihydroxydiphenylsulfone, chloro-2,4-dihydroxydiphenylsulfone, 5-chloro-4,4'-dihydroxydiphenylsulfone, 3'-chloro-4,4 ' Di- (hydroxyphenyl) -sulfone such as dihydroxydiphenylsulfone or bis- (4-hydroxyphenyl) Le) - ether, 4,3 '- (or 4,2' or 2,2'-dihydroxy -
Diphenyl) ether, 4,4'-dihydroxy-2,6-dimethyldiphenyl ether, bis- (4-hydroxy-
3-isobutylphenyl) -ether, bis- (4-hydroxy-3-isopropylphenyl) -ether, bis- (4-hydroxy-3-chlorophenyl) -ether, bis- (4-hydroxy-3-fluorophenyl) )
-Ether, bis- (4-hydroxy-3-bromophenyl) -ether, bis- (4-hydroxynaphthyl)
Ether, bis- (4-hydroxy-3-chloronaphthyl) -ether, bis- (2-hydroxybiphenyl) -ether, 4,4'-dihydroxy-2,6-dimethoxydiphenyl ether, 4,4'-dihydroxy- Di- (hydroxyphenyl) -ethers, such as 2,5-diethoxydiphenyl ether, and 1,1-bis- (4-
(Hydroxyphenyl) -2-phenylethane, 1,3,3-
Trimethyl-1- (4-hydroxyphenyl) -6-hydroxyindane and 2,4-bis- (p-hydroxyphenyl) -4-methylpentane are also suitable.

Another preferred group of such polynuclear dihydric phenols is a compound of the general formula (Where R ₃ is a methyl or ethyl group, R ₂ is an alkylidene group having 1 to 9 carbon atoms or another alkylene group, p is 0 to
4) For example, 1,4-bis- (4-hydroxybenzyl) -benzene, 1,4-bis- (4-hydroxybenzyl) -tetramethylbenzene, 1,4-bis-
(4-hydroxybenzyl) -tetraethylbenzene,
1,4-bis- (p-hydroxycumyl) -benzene, 1,3
-Bis- (p-hydroxycumyl) -benzene and the like.

Other polynuclear polyhydric phenols (A-2) include, for example, initial condensates of phenols and carbonyl compounds (eg, phenol resin initial condensates, condensation reaction products of phenol and acrolein, phenols). And glyoxal condensation reaction product, condensation reaction product of phenol and pentanediallyl, condensation reaction product of resorcinol and acetone, xylene-phenol-formalin initial condensation product), condensation product of phenols and polychloromethylated aromatic compounds (Example: condensation product of phenol and bischloromethylxylene) and the like.

Thus, here, the polyhydroxyl compound (B)
The polyphenol (A) having at least one aromatic nucleus is reacted with an alkylene oxide in the presence of a catalyst that promotes the reaction between the OH group and the epoxy group, and the phenol residue is formed by an ether bond obtained. —ROH (where R is an alkylene oxide-derived alkylene group) or (and) — (RO) _n H (where R is an alkylene oxide-derived alkylene group and one polyoxyalkylene chain Is a compound having an atomic group of 2 or an integer of 2 or more indicating the number of polymerization of the oxyalkylene group. In this case, the ratio of the polyhydric phenol (A) to the alkylene oxide is 1: 1 (mol: mol) or more, but preferably, the ratio of the alkylene oxide to the OH group of the polyhydric phenol (A) is 1 : 1 to 10, preferably 1: 1 to 3 (equivalent: equivalent).

Examples of the alkylene oxide include, for example, ethylene oxide, propylene oxide, and butylene oxide, and those which form a side chain when these react with the polyhydric phenol A to form an ether bond are particularly preferable. As propylene oxide,
There are 1,2-butylene oxide and 2,3-butylene oxide, and propylene oxide is particularly preferred.

One particularly preferred group of such polyhydroxyl compounds is represented by the general formula (Wherein Y ′, Y ₁ , m, z and R ₁ are the same as those of the formula (1-1), R is an alkylene group having 2 to 4 carbon atoms, n ₁ and n ₂ are 1 to 3) Is a polyhydroxyl compound represented by the formula:

Yet another preferred class of such polyhydroxyl compounds is represented by the general formula (Wherein R ₁ , R ₂ and R ₃ are the same as those in the formula (1-2), R is an alkylene group having 2 to 4 carbon atoms, n ₁ and n ₂ are 1
Which is a value of ３3).

Here, epihalohydrin (b) has the general formula: (Where Z is a hydrogen atom, a methyl group, an ethyl group, and X ′ is a halogen atom). Examples of such epihalohydrin (b) include, for example, epichlorohydrin, epibromohydrin, 1,2 -Epoxy-2-methyl-3-chloropropane, 1,2-epoxy-2-ethyl-3-chloropropane and the like.

Epihalohydrin (b) and polyhydric phenol (A)
Alternatively, examples of the acidic catalyst that promotes the reaction with the polyhydroxyl compound (B) include Lewis acids such as boron trifluoride, stannic chloride, zinc chloride, and ferric chloride; Boron fluoride-ether complex compound) or a mixture thereof can be used.

Similarly, basic catalysts that promote the reaction between epihalohydrin (b) and polyhydric phenol (A) include alkali metal hydroxides (eg, sodium hydroxide), alkali metal alcoholates (eg, sodium ethylate), Tertiary amine compounds (eg, triethylamine, triethanolamine), quaternary ammonium compounds (eg, tetramethylammonium bromide), or mixtures thereof, can be used to form glycidyl ether simultaneously with the reaction. Alternatively, as a basic compound that forms a glycidyl ether by closing a halohydrin ether formed as a result of the reaction by a dehydrohalogenation reaction, an alkali metal hydroxide (eg, sodium hydroxide), an alkali metal aluminate ( Example: sodium aluminate) If is often used.

Thus, these catalysts or basic compounds can be used as such or as a suitable inorganic or (and) organic solvent solution.

The epoxy resin (I-2) having an average of more than one substituted or unsubstituted glycidyl ester group in a molecule includes a polyglycidyl ester of an aliphatic polycarboxylic acid or an aromatic polycarboxylic acid. An epoxy resin obtained by polymerizing glycidyl methacrylate synthesized from epihalohydrin (b) represented by the general formula (2) and methacrylic acid is also included.

Examples of the epoxy resin (I-3) having an average of one or more N-substituted or unsubstituted 1,2-epoxypropyl groups in a molecule include aromatic amines (for example, aniline or an alkyl substituent on the nucleus). An epoxy resin obtained from the aniline having the formula (1) and the epihalohydrin (b) represented by the general formula (2), an initial condensate of an aromatic amine and an aldehyde (for example, an aniline-formaldehyde initial condensate, an aniline-phenol-formaldehyde initial compound) An epoxy resin obtained from the condensate) and epihalohydrin (b), and hydantoin diglycidyl ether.

In addition, conventionally known epoxy resins containing adjacent epoxy groups such as various epoxy resins described in "Production and Application of Epoxy Resin" (edited by Hiroshi Kakiuchi) are used.

Urethane prepolymer (II-a) used in the present invention
Isocyanate groups 1 to 10% by weight obtained by reacting a polyhydroxy compound such as polyether polyol, polyester polyol and a mixture thereof with an excess of a polyisocyanate compound in the same manner as in a normal NCO-containing urethane prepolymer production method; It is a urethane polymer having an average molecular weight of 600 to 20,000.

As the preferred polyether polyol,
For example, a general formula R [(OR ₁ ) _n OH] _p (where R is a polyhydric alcohol residue; (OR ₁ ) _n is a polyoxyalkylene chain comprising an oxyalkylene group having an alkylene group having 2 to 4 carbon atoms) n is a number indicating the degree of polymerization of the oxyalkylene group and is a number corresponding to a molecular weight of 100 to 4,500; and p is preferably a polyether polyol represented by 2 to 4).

Preferred examples of the polyhydric alcohol corresponding to the above general formula include, for example, aliphatic dihydric alcohols (eg, ethylene glycol, propylene glycol, 1,4-butylene glycol, neopentane glycol), and trihydric alcohols (eg, glycerin). , Trioxyisobutane, 1,2,3-butanetriol, 1,2,3-pentanetriol, 2-methyl-1,2,3-propanetriol, 2-methyl-2,3,4
-Butanetriol, 2-ethyl-1,2,3-butanetriol, 2,3,4-pentanetriol, 2,3,4-hexanetriol, 4-propyl-3,4,5-heptanetriol, 2, 4-dimethyl-2,3,4-pentanetriol, pentamethylglycerin, pentaglycerin, 1,2,4-butanetriol, 1,2,4-pentanetriol, trimethylolpropane, etc., tetrahydric alcohols (eg: Erythrit, pentaerythritol, 1,2,3,4-pentanetetrol, 2,3,4,5-hexanetetrol, 1,2,3,5-pentanetetrol, 1,3,4,5- Hexane tetrol, etc.), pentahydric alcohol (eg, adnit, arabbit, xylit, etc.), hexahydric alcohol (eg, sorbitol, mannitol,
And the like).

The polyhydric alcohol is preferably a di- to tetra-valent alcohol, particularly preferably propylene glycol or glycerin.

In addition, the polyether polyol represented by the above general formula is prepared by adding a polyhydric alcohol having 2 to 4 carbon atoms by a conventional method.
Can be produced by adding an alkylene oxide to a desired molecular weight.

Examples of the alkylene oxide having 2 to 4 carbon atoms include ethylene oxide, propylene oxide, and butylene oxide, and it is particularly preferable to use propylene oxide.

Examples of the polyester polyol include conventionally known polyesters produced from polycarboxylic acids and polyhydric alcohols, and polyesters obtained from lactams.

Such polycarboxylic acids include, for example, benzenetricarboxylic acid, adipic acid, succinic acid, spearic acid, sebacic acid, oxalic acid, methyl adipic acid, glutaric acid, pimelic acid, azelaic acid, phthalic acid, terephthalic acid, isophthalic acid, thiodiacid Propionic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid or any suitable carboxylic acid similar thereto can be used.

As the polyhydric alcohol, for example, ethylene glycol, propylene glycol, 1,4-butanediol,
1,3-butanediol, 1,5-pentanediol, 1,6-
Hexanediol, bis (hydroxymethylchlorohexane), diethylene glycol, 2,2-dimethylpropylene glycol, 1,3,6-hexanetriol, trimethylolpropane, pentaerythritol, sorbitol, glycerin or any suitable polyvalent similar thereto Alcohol can be used.

In addition, polytetramethylene glycol, polycaprolactone glycol, and the like can be used as the polyhydroxyl compound.

The urethane prepolymer used in the present invention is (II-
a) can be obtained by reacting a polyhydroxy compound such as the above-mentioned polyether polyol or polyester polyol or a mixture thereof, or a mixture thereof with an OH group-containing glyceride such as castor oil and a polyisocyanate. it can.

The polyisocyanate compound represented by the general formula (Where ○ is a benzene ring or naphthalene ring, -NCO is a nuclear-substituted isocyanate group, Z is a nuclear-substituted halogen atom or an alkyl or alkoxyl group having 3 or less carbon atoms,
n is a diisocyanate represented by 0, 1 or 2 (for example,
2,4-toluylene diisocyanate, 2,6-toluylene diisocyanate, 1,4-naphthylene diisocyanate,
1,5-naphthylene diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate,
1-isopropylbenzol-2,4-diisocyanate): General formula (Where ○ is a benzene ring or naphthalene ring,-(C
H ₂ ) _m NCO is a nuclear-substituted alkylene isocyanate group, Z is a nuclear-substituted halogen atom or an alkyl or alkoxyl group having 3 or less carbon atoms, m is 1 or 2, n is 1 or 2) (Example: ω, ω′-Diisocyanate-1,2-dimethylbenzol, ω, ω′-diisocyanate-1,3-dimethylbenzol): General formula (Where A is —CH ₂ — or An alkylene group having 3 or more carbon atoms, ○ is a benzene ring or a naphthalene ring, Z is a halogen-substituted halogen atom or an alkyl or alkoxy group having 3 or less carbon atoms, and n is 0, 1 or 2; : 4,4'-diphenylmethane diisocyanate, 2,2'-dimethylphenylmethane-4,4'-diisocyanate, diphenyldimethylmethane-4,4'-diisocyanate, 3,3'-dichlorodiphenyldimethylmethane-4,4 '-Diisocyanate), general formula (Where Z is a halogen-substituted halogen atom or an alkyl or alkoxy group having 3 or less carbon atoms, m is 0 or 1, n is 0,
1 or 2) (eg, biphenyl-2,4'-diisocyanate, biphenyl-4,4'-diisocyanate, 3,3'-dimethylbiphenyl-4,4'-)
Diisocyanate, 3,3'-dimethoxybiphenyl-4,
4'-diisocyanate), diphenylsulfone-4,4 '
Diisocyanate, a diisocyanate obtained by hydrogenating an aromatic ring contained in the above isocyanate (eg, dicyclohexane-4,4'-diisocyanate, ω, ω '
Diisocyanate-1,2-dimethylbenzene, ω,
ω'-diisocyanate-1,3-dimethylbenzene),
Diisocyanates containing substituted urea groups obtained by the reaction of 2 moles of diisocyanate with 1 mole of water (eg urea diisocyanate obtained by reacting 1 mole of water with 2 moles of 2,4-toluylene diisocyanate), aromatic Uretdione diisocyanate, propane-1,2-diisocyanate, 2,3-dimethylbutane-2,3-diisocyanate, 2-methylpentane-2,4-diisocyanate, octane- obtained by dimolecular polymerization of diisocyanate by a known method. Examples thereof include 3,6-diisocyanate, 3,3-dinitropentane-1,5-diisocyanate, octane-1,6-diisocyanate, and hexamethylene diisocyanate.

The urethane prepolymer (II-a) obtained from such an isocyanate compound and the above-mentioned polyhydroxyl compound such as polyether polyol and polyester polyol can be obtained by a usual method. When performing a urethane prepolymer formation reaction, the reaction temperature is usually
The temperature is 40 to 140 ° C, preferably 60 to 120 ° C. In performing the urethane prepolymer production reaction, a known urethane polymerization catalyst to promote the reaction, for example, dibutyltin dilaurate, stannous octoate, an organic metal compound such as stannas octoate, triethylenediamine, triethylamine, 1,8 Tertiary amine compounds such as -diazabicyclo [5.4.0] undecene-7 can also be used.

When the molecular weight of the compound (II-a) is less than 600, flexibility is not exhibited, and when it exceeds 20,000, compatibility with the epoxy resin is lost.

Compounds having a phenolic hydroxyl group that undergo a block reaction with the NCO group-containing urethane prepolymer (II-a) (II
-B) includes alkylphenols such as phenol, cresol (metacresol, orthocresol, paracresol and mixtures thereof), xylenol, octylphenol, nonylphenol, dinonylphenol, para-tert-butylphenol and sec-butylphenol, and styrenated phenol. And a mixture of two or more of these phenols.

The blocking reaction of the isocyanate / phenol is performed by a known reaction method. Reaction temperature is 50 ℃ ~ 150 ℃
The reaction is preferably performed at 70 ° C. to 120 ° C., and the reaction time is preferably about 1 to 7 hours. The equivalent ratio is NCO / phenolic OH = 1 / 1.0 to 1 / 2.0.

The blocking agent is added at any stage of the above reaction and allowed to react to obtain a blocked isocyanate compound (II).

As an addition method, it is added at the end of a predetermined polymerization,
Alternatively, it is possible to add them at the beginning of the polymerization or to add a part at the beginning of the polymerization and add the remainder at the end of the polymerization. A preferred method is to add at the end of the polymerization. In the reaction, a known urethane polymerization catalyst may be added to promote the reaction.

Examples of the carboxylic acid dihydrazide compound (III) include adipic dihydrazide, sebacic dihydrazide, isophthalic dihydrazide, 1,3-bis- (hydrazinocarboethyl) -5-isopropylhydantoin Eicosane diacid dihydrazide Hydroquinone diglycolic acid dihydrazide, resorcinol diglycolic acid dihydrazide, 4,4′-ethylidene bisphenol diglycolic acid dihydrazide, And the like.

Further, in addition to the above-mentioned carboxylic dihydrazides, dicyandiamide (DICY) as a curing agent or a curing accelerator,
Imidazoles, tertiary amines, tertiary amine-containing modified amines, dichlorobenzene mono urea (DCMU), alkyl urea compounds (melamine, Benzokuanamin), BF ₃ - monoethylamine, BF ₃ - combination aniline compound salts such as This is also included in the present invention.

In the present invention, the mixing ratio of the epoxy resin and the blocked isocyanate compound is suitably epoxy resin / blocked isocyanate compound = 5 to 90/95 to 10 (% by weight), preferably epoxy resin / blocked isocyanate compound = 10 to 40/90 to 60 (% by weight).

(Epoxy resin + blocked isocyanate compound) The amount of carboxylic acid dihydrazide for curing is such that the reaction ratio of epoxy equivalent of epoxy resin / active hydrogen equivalent of dihydrazide compound = 1 / 0.5 to 1.5, the sum of the amount of the NH ₂ equivalents = 1 / 0.6-1.5 of the isocyanate equivalent / dihydrazide compound of isocyanate compound is preferred.

In addition to the above essential components, the composition according to the invention comprises reactive diluents, non-reactive diluents and extenders, fillers and / or reinforcing agents, pigments, solvents, plasticizers, leveling agents, thixotropic agents , A conventional modifier such as a flame-retardant substance or a release agent. The following are examples of suitable diluents, extenders, reinforcing agents, fillers and pigments that may be used in this composition. Monoglycidyl ether, DO
P, DBP, xylene resin, benzyl alcohol, tetrahydrofurfuryl alcohol, bitumen such as alloizer, coal tar, bitumen, textile fiber, fibrous material, glass fiber, synthetic fiber, asbestos fiber, boron fiber, carbon fiber,
Cellulose, polyethylene powder, clay, sand, rock, quartz powder, mineral silicate such as mica, asbestos powder, crushed shale, kaolin, aluminum hydroxide, powdered chalk, gypsum, antimony trioxide, bentonite, silica airgel, lithopone Oxide pigments such as barite, titanium dioxide, titanium dioxide, talc, calcium carbonate, carbon black, graphite, iron oxide, or metal powders such as aluminum powder or iron powder.

Suitable solvents for modifying the curable composition include:
Examples include toluene, xylene, n-propanol, butyl acetate, acetone, methyl ethyl ketone, diacetone, ethanol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether and ethylene glycol monobutyl ether.

Suitable plasticizers for modifying the curable composition include, for example, dibutyl-, dioctyl- and dinonyl esters of phthalic acid, tricresyl phosphate, trixylenyl phosphate and polypropylene glycol.

Leveling agents which may be added when the curable compositions described above are to be used, especially for surface protection, include, for example, silicones, acetylbutylcellulose, polyvinyl butyrate, waxes, stearate and the like.

The curable composition can be produced by a known method using a known mixing device (eg, stirrer, kneader, roller).

〔Example〕

Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples. The parts in the examples represent parts by weight.

Production Example 1 1000 parts of polypropylene glycol (molecular weight: 2,000) and 174 parts of toluylene diisocyanate (molecular weight: 174) were reacted at 70 ° C. for 5 hours in a two-necked flask equipped with a stirrer, a thermometer and a nitrogen inlet tube. Isocyanate equivalent 1174 (NC
(O content: 3.6%) to give a urethane prepolymer, followed by the addition of 242 parts of nonylphenol (molecular weight: 220) and 0.2 parts of a catalyst.
The mixture was reacted at 0 ° C. for 5 hours to obtain a blocked isocyanate compound-A in which isocyanate groups were completely disappeared by an infrared absorption spectrum (blocked isocyanate equivalent: 140).
0).

Production Example 2 1500 parts of polypropylene glycol (molecular weight 3000) and 174 parts of toluylene diisocyanate (molecular weight 174) were obtained in the same manner as in Production Example 1, followed by 242 parts of nonylphenol (molecular weight 220) and 0.2 part of a catalyst. The reaction was carried out in the same manner to obtain a blocked isocyanate compound-B (blocked isocyanate equivalent: 1900).

Production Example 3 1000 parts of polytetramethylene glycol (molecular weight: 2,000) and 174 parts of toluylene diisocyanate (molecular weight: 174) were reacted in the same manner as in Production Example 1 to obtain a urethane prepolymer.
Then 242 parts of nonylphenol (molecular weight 220) and 0.2 parts of catalyst
And then reacted in the same manner to obtain a blocked isocyanate compound-C (blocked isocyanate equivalent: 140
0).

Example 1 Epoxy resin, blocked isocyanate compound-A
The storage stability and the physical properties of the cured product of the compositions shown in Table 1 using adipic dihydrazide as the carboxylic acid dihydrazide compound were examined. In addition, the number which shows the compounding composition in a table | surface is a number of parts.

Example 2 Epoxy resin, blocked isocyanate compound-B
With respect to the compositions shown in Table 2 using dihydrazide and sebacic acid, storage stability and physical properties of cured products were examined.

Example 3 Epoxy resin, blocked isocyanate compound-A
The physical properties of the cured product were examined for the compositions shown in Table 3 using phthalazide hydrazide or isophthalic acid dihydrazide.

Example 4 Epoxy resin, blocked isocyanate compound-A
For the compositions shown in Table 4 using the above and adipic dihydrazide, storage stability and physical properties of a cured product were examined.

Example 5 Epoxy resin, blocked isocyanate compound-C
With respect to the compositions shown in Table 5 using the above and adipic dihydrazide, storage stability and physical properties of a cured product were examined.

 ──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Akio Ogawa 7-35 Higashiogu, Arakawa-ku, Tokyo Asahi Denka Kogyo Co., Ltd. (56) References JP-A-51-145598 (JP, A) JP-A Sho 60-228583 (JP, A) JP-B Hei 6-94496 (JP, B2) Keiji Iwata, "Plastic Materials Course 2 Polyurethane Resin" June 30, 1969, Published by Nikkan Kogyo Shimbun, No. 51-52 page

Claims (1)

(57) [Claims] 1. An epoxy resin (I) having an average of more than one adjacent epoxy group in a molecule, and an average of more than one isocyanate group in a molecule obtained from a polyhydroxy compound and an excess of a polyisocyanate compound. Having an isocyanate group content of 1 to 10% by weight,
Urethane polymer having an average molecular weight of 600 to 20,000 (II-a)
Is a compound (II-b) having a phenolic hydroxyl group, NC
One-part curable epoxy containing, as essential components, a blocked isocyanate compound (II) obtained by masking at an O / phenolic hydroxyl equivalent ratio of 1 / 1.0 to 1 / 2.0, and a carboxylic acid dihydrazide compound (III) Blocked urethane composition.