JPH05155973A - Curable epoxidized blocked urethane composition - Google Patents

Abstract

PURPOSE:To prepare the subject compsn. which is excellent in storage stability and adhesion, cures at a relatively low temp., and gives a cured article excellent in rubber elasticity and flexibility by compounding an epoxy resin, a specific blocked isocyanate compd., and a latent curing agent. CONSTITUTION:An epoxy resin having on the average more than one vicynal epoxy group, a blocked isocyanate compd. prepd. by masking a urethane prepolymer having more than one NCO group in the molecule, an NCO group content of 1-10wt.%, and an average mol.wt. of 600-20,000 and prepd. by reacting a polyhydroxy compd. with an excess amt. of a polyisocyanate compd. with a compd. of the formula (wherein R1 is cycloalkyl; and R2 is 1-9C alkyl or cycloalkyl) in an equivalent ratio of the NCO groups to the secondary amino groups of 1:1 to 1:2, and a latent curing agent are compounded to give the objective compsn., which is excellent in storage stability and cures in a short time at a relatively low temp.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a curable epoxy blocked urethane composition. In detail,
The present invention relates to a one-pack type thermosetting 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 giving a cured product having excellent mechanical strength, adhesion and rubber-like elasticity.

[0002]

2. Description of the Related Art Conventionally, it has been desired to develop a one-pack latent curing type epoxy resin composition as a structural adhesive, and a method using a curing agent such as an imidazole compound or a salt obtained by reacting an imidazole compound with an acid. Has been provided.

However, such a conventional one-pack type curable epoxy resin composition is still insufficient in its potential, and the curing reaction gradually progresses even at room temperature, so that the storage stability is not yet satisfactory. Potable time is 10 days to 2
It was only 0 days. Further, even when various kinds of flexible epoxy resins such as NBR-modified epoxy resin and conventional urethane-modified epoxy resin were used as the cured product, sufficient flexibility, rubber-like elasticity and high peel strength could not be obtained. Furthermore, the conventional one-pack type curable epoxy resin composition requires a high temperature and a long time for curing, and is, for example, 150 to 200 ° C.
If it is not cured for several hours, a cured product having satisfactory physical properties cannot be obtained, and when cured at a relatively low temperature for a short time, the peel strength and the rubber-like elasticity are extremely poor.

Therefore, the advent of a new one-pack type curable improved epoxy resin composition without such drawbacks has been desired. As a solution to the above problems, in JP-A-62-265323, a flexible epoxy resin is used as a main component, an epoxy resin is applied to isophoronediamine as a curing agent, and the epoxy resin is masked with a phenol resin. A one-component curing type epoxy resin composition for use has been proposed.

[0005]

However, the above-mentioned curing system has more storage stability, curability at a relatively low temperature for a short time, and flexibility of the cured product as compared with the conventional one-component epoxy curing system. Although it has been improved, a cured product having rubber-like elasticity cannot be obtained, and the inherent defect of the epoxy resin that it loses flexibility particularly in a low temperature region has not been improved.

[0006]

Therefore, as a result of earnest studies, the present inventors have found that the use of a latent curing agent in combination with an ordinary epoxy resin in combination with a blocked isocyanate compound results in excellent storage stability. It can be cured in a short time even at extremely low temperature, and the cured product has rubber-like elasticity, especially at low temperatures,
The present invention has been accomplished by finding that a one-component curing type epoxy blocked urethane resin composition having excellent flexibility and excellent adhesiveness, particularly peeling strength can be obtained.

That is, the 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 groups in the molecule, a polyhydroxy compound and an excess polyisocyanate compound. 1 to 10% by weight of an isocyanate group having an average of more than one isocyanate group in the molecule, an average molecular weight of 6
The urethane prepolymer (II-a) of 00-20,000 has the general formula

## STR00002 ## R ₁ --NH--R ₂ (wherein R ₁ is a cycloalkyl group, R ₂ is 1 to 1 carbon atoms).
9 alkyl group, cycloalkyl group, R ₁ and R ₂ may be the same or different) (II-b),
NCO / secondary monoamino group equivalent ratio 1 / 1.0 to 1/2.
A blocked isocyanate compound (II) obtained by masking with 0 and a latent curing agent (III) are contained as essential components.

The preferred epoxy resin (I) is represented by the formula:

[Chemical 3] (In the formula, Z is a hydrogen atom, a methyl group, an ethyl group) An epoxy resin (I-1) having on average more than one substituted or unsubstituted glycidyl ether group represented by the formula:

[0009]

[Chemical 4] (In the formula, Z is a hydrogen atom, a methyl group, an ethyl group) An epoxy resin (I-2) having an average of more than one substituted or unsubstituted glycidyl ether group represented by the formula:

[0010]

[Chemical 5] (In the formula, Z is a hydrogen atom, a methyl group, an ethyl group) and an epoxy resin (I- having an average of more than one N-substituted or unsubstituted 1,2-epoxypropyl group in the molecule (I-
3) etc. are included. Further, particularly preferable epoxy resin (I) is an epoxy resin having an epoxy equivalent of 180 to 500.

An epoxy resin (I-) having more than one substituted or unsubstituted glycidyl ether group in the molecule
1) includes an epoxy resin in which a phenolic hydroxyl group is glycidyl etherified and an epoxy resin in which an alcoholic hydroxyl group is glycidyl etherified,
As a preferable example of such an epoxy resin (I-1), 1
Polyglycidyl ether (I-1-1) of polyhydric phenol having 1 or 2 or more aromatic nuclei and 1 or 2
Polyhydric phenol having at least one aromatic nucleus and 2 to 2 carbon atoms
Examples thereof include polyglycidyl ether (I-1-2) of an alcoholic polyhydroxyl compound which is derived by an addition reaction with four alkylene oxides.

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

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

As the polyhydric phenol (A) having at least one aromatic nucleus, there are a mononuclear polyhydric phenol (A-1) having one aromatic nucleus and two or more aromatic nuclei. There is a polynuclear polyhydric phenol (A-2). Examples of such mononuclear polyphenols (A-1) include resorcinol, hydroquinone, pyrocatechol, phloroglucinol, 1,5-dihydroxynaphthalene, 2,7.
-Dihydroxy naphthalene, 2,6-dihydroxy naphthalene and the like.

Further, examples of the polynuclear polyhydric phenol (A-2) include general formula:

[Chemical 6] (In the formula, Ar is an aromatic divalent hydrocarbon such as a naphthylene group and a phenylene group, and a phenylene group is preferable for the purpose of the present invention. Y ′ and Y ₁ may be the same or different, and a methyl group, n -Alkyl group such as propyl group, n-butyl group, n-hexyl group and n-octyl group, preferably an alkyl group having up to 4 carbon atoms or a halogen atom, that is, a chlorine atom, a bromine atom, an iodine atom or a fluorine atom. An atom or an alkoxy group such as a methoxy group, a methoxymethyl group, an ethoxy group, an ethoxyethyl group, an n-butoxy group and an amyloxy group, preferably an alkoxy group having a maximum of 4 carbon atoms. Substituents may be the same as or different from each other in addition to the hydroxyl group in either or both of the hydrogen groups, m and z are each an aromatic ring (Ar) which can be substituted by the substituent. An integer having a value of from 0 corresponds to the number of atom (zero) to the maximum value, .R ₁ which may be the same or different values, for example,

[0016]

[Chemical 7]

--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,
Hexamethylene group, 2-ethylhexamethylene group, octamethylene group, nonamethylene group, decamethylene group or alkylidene group such as ethylidene group, propylidene group, isopropylidene group, isobutylidene group, amylidene group, isoamylidene group, 1-phenylethylidene group or cyclic Aliphatic group such as 1,4-cyclohexylene group, 1,3-cyclohexylene group, cyclohexylidene group, halogenated alkylene group, halogenated alkylidene group, halogenated cyclic aliphatic group or alkoxy- And aryloxy-substituted alkylidene groups or alkoxy- and aryloxy-substituted alkylene groups or alkoxy-substituted alkylene groups or alkoxy- and aryloxy-substituted Cyclic aliphatic group such as a methoxy methylene, ethoxymethylene, ethoxy ethylene group, 2-ethoxy trimethylene group, 3-ethoxy pentamethylene group, 1,4 (2-methoxy-cyclohexane)
Group, phenoxyethylene group, 2-phenoxytrimethylene group, 1,3- (2-phenoxycyclohexane) group or alkylene group such as phenylethylene group, 2-phenyltrimethylene group, 1-phenylpentamethylene group,
2-phenyl decamethylene group or aromatic such as phenylene group, naphthylene group or halogenated aromatic group such as 1,4- (2-chlorophenylene) group, 1,4-
(2-Bromphenylene) group, 1,4- (2-fluorophenylene) group or aromatic group substituted with alkoxy and aryloxy, for example, 1,4- (2-methoxyphenylene) group, 1,4- (2- Ethoxyphenylene) group, 1,4-
(2-n-Propoxyphenylene) group, 1,4- (2-phenoxyphenylene) group or 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, a divalent group such as a divalent hydrocarbon group such as a 1,4- (2-n-dodecylphenylene) group, or R ₁ is, for example, a compound represented by the formula:

[0018]

[Chemical 8]

As in the case of compounds represented by
It may be a ring fused to one group, or R
₁ can also be a polyalkoxy group such as a polyethoxy group, a polypropoxy group, a polythioethoxy group, a polybutoxy group, a polyphenylethoxy group, or R ₁
Can be a group containing a silicon atom such as a polydimethylsiloxy group, a polydiphenylsiloxy group, a polymethylphenylsiloxy group, or R ₁ is an aromatic ring, a tertiary-amino group ether bond, a carbonyl group or Polynuclear dihydric phenols represented by two or more alkylene or alkylidene groups separated by a sulfur-containing bond such as sulfur or a sulfoxide.

Of these polynuclear dihydric phenols, particularly preferred are those of the general formula

[Chemical 9] (In the formula, Y ′ and Y ₁ have the same meanings as described above, and m and z
Is a value of 0 to 4, and R ₁ is preferably an alkylene group or alkylidene group having 1 to 3 carbon atoms or a formula

[0021]

[Chemical 10] It is a polynuclear dihydric phenol represented by).

Among examples of such dihydric phenols are 2,2-bis- (p-hydroxyphenyl) -propane, 2,4'-dihydroxydiphenylmethane and bis- (2), which are commonly referred to by the trade name Bisphenol A. -Hydroxyphenyl) -methane, 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-
A bis- (hydroxyphenyl) alkane such as (4-hydroxyphenyl) -1-phenylpropane or 4,
4'-dihydroxybiphenyl, 2,2'-dihydroxybiphenyl, dihydroxybiphenyl such as 2,4'-dihydroxybiphenyl or bis- (4-hydroxyphenyl) -sulfone, 2,4'-dihydroxydiphenylsulfone, chlor-2 Di- (hydroxyphenyl)-, such as 4,4-dihydroxydiphenyl sulfone, 5-chloro-4,4'-dihydroxydiphenyl sulfone, 3'-chloro-4,4'-dihydroxydiphenyl sulfone
Sulfone or bis- (4-hydroxyphenyl) -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-2,
Di- (hydroxyphenyl) -ethers such as 5-diethoxydiphenyl ether are included, and 1,1-bis- (4-hydroxyphenyl) -2-phenylethane,
1,3,3-trimethyl-1- (4-hydroxyphenyl)
-6-Hydroxyindane, 2,4-bis- (p-hydroxyphenyl) -4-methylpentane is also suitable.

Still another preferred group of such polynuclear dihydric phenols is the general formula

[Chemical 11] (In the formula, R ₃ is a methyl or ethyl group, R ₂ is a carbon number of 1 to
9 alkylidene groups or other alkylene groups, p
Is 0 to 4) and is, 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 can be mentioned.

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

Therefore, here, the polyhydroxyl compound
(B) is obtained by reacting the above-mentioned polyhydric phenol (A) having at least one aromatic nucleus with an alkylene oxide in the presence of a catalyst for promoting the reaction between an OH group and an epoxy group. -ROH (wherein R is an alkylene group derived from alkylene oxide) or (and)-(R
O) _n H (In the formula, R is an alkylene group derived from alkylene oxide, and one polyoxyalkylene chain may include different alkylene groups. N is 2 or 2 or more which represents the number of polymerization of the oxyalkylene group. It is a compound having an atomic group of (integer). In this case, the polyphenol
The ratio of (A) to alkylene oxide is 1: 1 (mol:
Mol) or more, but preferably the polyhydric phenol
The ratio of the alkylene oxide to the OH group of (A) is 1: 1 to 10, preferably 1: 1 to 3 (equivalent: equivalent).

Examples of the alkylene oxide include ethylene oxide, propylene oxide, butylene oxide, etc., and those which generate a side chain when they react with the polyhydric phenol A to form an ether bond are particularly preferable. Examples thereof include propylene oxide, 1,2-butylene oxide and 2,3-butylene oxide, and propylene oxide is particularly preferable.

A particularly preferred group of such polyhydroxy compounds is represented by the general formula

[Chemical 12] (In the formula, Y ′, Y ₁ , m, z and R ₁ are the same as those in the formula (1-1), R is an alkylene group having 2 to 4 carbon atoms, and n ₁ and n ₂ are 1 to It is a polyhydroxyl compound represented by 3).

Still another preferred group of such polyhydroxyl compounds is the general formula

[Chemical 13] (In the formula, R ₁ , R ₂ and R ₃ are the same as those in the above formula (1-2), R is an alkylene group having 2 to 4 carbon atoms, and n ₁ and n ₂ are values of 1 to 3. There is) a polyhydroxyl compound.

The epihalohydrin (b) here is
General formula:

[Chemical 14] (In the formula, 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, epibromhydrin, 1 Examples include 2,2-epoxy-2-methyl-3-chloropropane and 1,2-epoxy-2-ethyl-3-chloropropane.

As an acidic catalyst for promoting the reaction of the epihalohydrin (b) with the polyhydric phenol (A) or the polyhydroxyl compound (B), boron trifluoride, stannic chloride,
Lewis acids such as zinc chloride and ferric chloride, derivatives showing these activities (eg, boron trifluoride-ether complex compound), mixtures thereof and the like can be used.

Similarly, as the basic catalyst for promoting the reaction between the epihalohydrin (b) and the polyhydric phenol (A), an alkali metal hydroxide (eg sodium hydroxide), an alkali metal alcoholate (eg sodium ethylate) is used. ), A tertiary amine compound (eg: triethylamine, triethanolamine), a quaternary ammonium compound (eg: tetramethylammonium bromide), or a mixture thereof can be used. Alkali metal hydroxides (eg sodium hydroxide) and aluminate are basic compounds that either form halohydrin ethers resulting from the reaction or cyclize the resulting halohydrin ethers by dehydrohalogenation to form glycidyl ethers. Alkali metal salt (eg sodium aluminate) is convenient Often used.

However, it goes without saying that these catalysts or basic compounds can be used as they are or as a suitable inorganic or / and organic solvent solution.

An epoxy resin having an average of more than one substituted or unsubstituted glycidyl ester group in the molecule
Examples of (I-2) include polyglycidyl esters of aliphatic polycarboxylic acids or aromatic polycarboxylic acids. For example, glycidyl synthesized from epihalohydrin (b) represented by the general formula (2) and methacrylic acid. Epoxy resins such as those obtained by polymerizing methacrylate are also included.

In addition, N-substituted substituted or unsubstituted 1,2-
Examples of the epoxy resin (I-3) having an average of more than one epoxypropyl group in the molecule are aromatic amines (for example, aniline or aniline having an alkyl substituent in the nucleus) and the above general formula (2). Epihalohydrin (b)
And an epoxy resin obtained from an initial condensation product of an aromatic amine and an aldehyde (for example, aniline-formaldehyde initial condensation product, aniline-phenol-formaldehyde initial condensation product) and epihalohydrin (b), hydantoin diglycidyl Examples include ether.

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

Urethane prepolymer used in the present invention
(II-a) is an isocyanate group 1 obtained by reacting a polyhydroxy compound such as a polyether polyol, a polyester polyol and a mixture thereof with an excess polyisocyanate compound in the same manner as in the usual NCO-containing urethane prepolymer production method. -10 wt%, average molecular weight 6
It is a urethane polymer of 00 to 20000.

Preferred examples of the above polyether polyols include those represented by the general formula

Embedded image R [(OR ₁ ) _n OH] _p (wherein R is a polyhydric alcohol residue; (OR ₁ ) _n has 2 carbon atoms)
A polyoxyalkylene chain consisting of an oxyalkylene group having 4 alkylene groups; n is a number showing the degree of polymerization of the oxyalkylene group and corresponding to a molecular weight of 100 to 4500; p is preferably 2 to There is a polyether polyol represented by 4).

Preferred examples of polyhydric alcohols corresponding to the above general formula include, for example, aliphatic dihydric alcohols (eg:
Ethylene glycol, propylene glycol, 1,4-
Butylene glycol, neopentane glycol), trihydric alcohol (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 alcohol (eg, erythritol, pentaerythritol, 1,2,3,4-pentane tetrol, 2,
3,4,5-hexanetetrol, 1,2,3,5-pentanetetrol, 1,3,4,5-hexanetetrol, etc.),
Examples thereof include pentahydric alcohols (eg, adnit, arabite, xylit, etc.), hexahydric alcohols (eg, sorbit, mannitol, idit, etc.).

The polyhydric alcohol is preferably a dihydric to tetrahydric alcohol, and propylene glycol and glycerin are particularly preferable.

Further, the polyether polyol represented by the above general formula is produced by adding an alkylene oxide having 2 to 4 carbon atoms to such a polyhydric alcohol by a conventional method so as to have a desired molecular weight. You can

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

Examples of the above-mentioned polyester polyols include conventionally known polyesters produced from polycarboxylic acids and polyhydric alcohols or polyesters obtained from lactams. Examples of such polycarboxylic acids include benzenetricarboxylic acid, adipic acid, succinic acid, speric acid, sebacic acid, oxalic acid, methyladipic acid, glutaric acid, pimelic acid, azelaic acid,
Phthalic acid, terephthalic acid, isophthalic acid, thiodipropionic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid or any suitable carboxylic acid thereof can be used.

Examples of the polyhydric alcohol include ethylene glycol, propylene glycol, 1,4-butanediol, 1,3-butanediol, 1,5-pentanediol, 1,6-hexanediol and bis (hydroxymethyl). Chlorohexane), diethylene glycol, 2,
2-Dimethylpropylene glycol, 1,3,6-hexanetriol, trimethylolpropane, pentaerythritol, sorbitol, glycerin or any suitable polyhydric alcohol similar thereto can be used.

In addition, as a polyhydroxyl compound,
Polytetramethylene glycol, polycaprolactone glycol, etc. may also be used.

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

Further, as the polyisocyanate compound, a compound represented by the general formula

[Chemical 16] (In the formula, ◯ is a benzene ring or a naphthalene ring, -NC
O is a nucleus-substituted isocyanate group, Z is a nucleus-substituted halogen atom or an alkyl or alkoxyl group having 3 or less carbon atoms, and 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):

Hydrogenated toluylene diisocyanate such as obtained by hydrogenating an aromatic ring contained in the above isocyanate, a general formula

[Chemical 17] (Wherein ○ is a benzene ring or naphthalene ring,-(CH
₂ ) _m NCO is a nucleus-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, and n is 1 or 2) (eg, ω, ω′-diisocyanate-1,2-dimethylbenzol, ω, ω'−
Diisocyanate-1,3-dimethylbenzol):

1,3- or 1,4-bis (isocyanatomethyl) cyclohexane, as obtained by hydrogenating an aromatic ring contained in the above isocyanate, having the general formula

[Chemical 18] An alkylene group having 3 or more carbon atoms, such as ◯, a benzene ring or a naphthalene ring, Z is a halogen atom substituted with a nucleus, or an alkyl or alkoxy group having 3 or less carbon atoms, and n is 0, 1 or 2 and is a diisocyanate (eg, : 4,
4'-diphenylmethane diisocyanate, 2,2'-dimethyldiphenylmethane-4,4'-diisocyanate,
Diphenyldimethylmethane-4,4'-diisocyanate, 3,3'-dichlorodiphenyldimethylmethane-4,
4'-diisocyanate),

Dicyclohexylmethane diisocyanate as obtained by hydrogenating an aromatic ring contained in the above isocyanate, a general formula

[Chemical 19] (Wherein Z is a nuclear-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) and is represented by a diisocyanate (for example:
Biphenyl-2,4'-diisocyanate, biphenyl-
4,4'-diisocyanate, 3,3'-dimethylbiphenyl-4,4'-diisocyanate, 3,3'-dimethoxybiphenyl-4,4'-diisocyanate), diphenylsulfone-4,4'-diisocyanate, the above isocyanate A diisocyanate obtained by hydrogenating an aromatic ring contained in (e.g., dicyclohexane-4,4'-diisocyanate, ω, ω'-diisocyanate-1,2-dimethylbenzene, ω, ω'-diisocyanate-1, 3-dimethylbenzene), a diisocyanate containing a substituted urea group obtained by the reaction of 2 moles of diisocyanate with 1 mole of water (eg obtained by reaction of 1 mole of water with 2 moles of 2,4-toluylene diisocyanate) Urea diisocyanate), uretdione diisocyanate obtained by polymerizing two molecules of aromatic diisocyanate by a known method. Isocyanate, 1,2-diisocyanate, 2,3-dimethylbutane-2,3-diisocyanate, 2-methylpentane 2,
4-diisocyanate, octane-3,6-diisocyanate, 3,3-dinitropentane-1,5-diisocyanate, octane-1,6-diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, lysine diisocyanate, isophorone diisocyanate, 3- Isocyanate methyl-3,
Examples include 5,5-trimethylcyclohexyl isocyanate and metatetramethylxylylene diisocyanate. Polymers such as these dipolymers or tripolymers can also be used.

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 carrying out the urethane prepolymer formation reaction, the reaction temperature is usually 40 to 140 ° C, preferably 60 to 120 ° C. In carrying out the urethane prepolymer formation reaction, known urethane polymerization catalysts for promoting the reaction, for example, organometallic compounds such as dibutyltin dilaurate, stannous octoate, stannas octoate, triethylenediamine, triethylamine, 1,8 It is also possible to use tertiary amine compounds such as diazabicyclo [5.4.0] undecene-7.

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

The NCO group-containing urethane prepolymer (I
Suitable compounds (II-b) having a secondary monoamino group capable of undergoing a block reaction with I-a) include compounds corresponding to the above-mentioned general formula, such as dicyclohexylamine and di- (3,
5,5-trimethylcyclohexyl) amine, N-ethylcyclohexylamine, isopropylcyclohexylamine and the like are mentioned, and a mixture of two or more kinds of them is also included.

The blocking reaction of the isocyanate / compound having a secondary monoamino group is carried out by a known reaction method. The reaction temperature is preferably 50 ° C to 150 ° C, more preferably 70 ° C to 120 ° C, and the reaction time is preferably about 1 to 7 hours. The equivalent ratio is NCO / secondary monoamino group = 1 / 1.0 to 1 / 2.0.

The blocking agent can be added and reacted at any stage of the above reaction to obtain the blocked isocyanate compound (II).

The method of addition may be such that it is added at the end of a predetermined polymerization, or at the beginning of the polymerization, or it is partially added at the beginning of the polymerization and the rest is added at the end of the polymerization. Preferably, it is added at the end of the polymerization. During the reaction, it is also possible to add a known urethane polymerization catalyst to accelerate the reaction.

As the latent curing agent (III), adipic acid dihydrazide, sebacic acid dihydrazide, isophthalic acid dihydrazide, 1,3-bis- (hydrazinocarboethyl) -5-isopropylhydantoin,

[Chemical 20] Hydroquinone diglycolic acid dihydrazide, resorcinol diglycolic acid dihydrazide, 4,4′-ethylidene bisphenol diglycolic acid dihydrazide,

[Chemical 21] Dicyandiamide (DICY), imidazoles, tertiary amines, tertiary amine-containing modified amines, dichlorobenzene mono urea (DCMU), alkyl urea compounds (melamine, Benzokuanamin), BF ₃ - monoethylamine, BF ₃ -
Examples include aniline compound salts and the like, and a mixture of two or more of these is also included.

In the present invention, the compounding ratio of the epoxy resin and the blocked isocyanate compound is such that the epoxy resin and the blocked isocyanate compound = 5 to 90/95 to 10
(Wt%) is suitable, preferably epoxy resin / blocked isocyanate compound = 10-90 / 90-10
(% By weight).

The compounding amount of the latent curing agent for curing (epoxy resin + blocked isocyanate compound) is
(Epoxy resin + blocked isocyanate compound) / latent curing agent = 100 / 0.5 to 50 (weight ratio), and preferably 100/3 to 30 (weight ratio).

In addition to the essential ingredients mentioned above, the composition according to the invention comprises reactive diluents, non-reactive diluents and extenders, fillers and / or reinforcing agents, pigments, solvents, plasticizers, leveling agents. ,
It may contain conventional modifiers such as thixotropic agents, flame retardants, mold release agents and the like. The following are suitable diluents, extenders, which may be used in this composition:
Examples are reinforcing agents, fillers and pigments. Bituminous materials such as monoglycidyl ether, DOP, DBP, xylene resin, benzyl alcohol, tetrahydrofurfuryl alcohol, allosizer, coal tar, bitumen, textile fiber, fiber material, glass fiber, synthetic fiber, asbestos fiber, boron fiber, carbon fiber , Cellulose, polyethylene powder, clay,
Sand, rock, quartz powder, mineral silicates such as mica, asbestos powder, ground shale, kaolin, aluminum hydroxide,
Powdered chalk, gypsum, antimony trioxide, bentonite, silica aerogel, lithopone, barite, titanium dioxide, talc, calcium carbonate, carbon black,
Graphite, oxide pigments such as iron oxide, or metal powders such as aluminum powder or iron powder.

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

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

When the above-mentioned curable composition is to be used especially for surface protection, leveling agents which may be added include, for example, silicone, acetylbutyl cellulose, polyvinyl butyrate, wax and stearate. is there.

The above-mentioned curable composition can be produced by a conventional method using a known mixing device (stirrer, kneader, roller, etc.).

[0064]

The present invention is described in detail below with reference to examples, but the present invention is not limited to these examples. In addition, the part in an Example represents a weight part.

Production Example 1 1000 parts of polypropylene glycol (molecular weight 2000) and 174 parts of toluylene diisocyanate (molecular weight 174) were placed at 70 ° C. in a 2 liter four-necked flask equipped with a stirrer, a thermometer and a nitrogen inlet tube. After reacting for 5 hours, a urethane prepolymer having an isocyanate equivalent weight of 1174 (NCO content of 3.6%) was obtained, and subsequently 141 parts of isopropylcyclohexylamine (molecular weight 141) was added. A blocked isocyanate compound-A having completely disappeared groups was obtained (blocked isocyanate equivalent 1315).

Production Example 2 A urethane prepolymer was obtained in the same manner as in Production Example 1 except that 1000 parts of polypropylene triol (molecular weight 3000) and 174 parts of toluylene diisocyanate (molecular weight 174) were obtained.
Subsequently, 181 parts of dicyclohexylamine (molecular weight 181) was added and reacted in the same manner to obtain blocked isocyanate compound-B (blocked isocyanate equivalent weight 1350).

Production Example 3 Polytetramethylene glycol (molecular weight 2000) 100
0 parts and isophorone diisocyanate (molecular weight 222) 22
2 parts of dibutyltin dilaurate and 0.02 part of dibutyltin dilaurate were reacted in the same manner as in Production Example 1 to obtain a urethane prepolymer, and subsequently 181 parts of dicyclohexylamine (molecular weight 181) was added and reacted in the same manner to obtain a blocked isocyanate compound-C. Was obtained (blocked isocyanate equivalent weight 1400).

Example 1 Epoxy Resin, Blocked Isocyanate Compound-A and ACR with Adipic Dihydrazide as Latent Curing Agent
The compositions of Table 1 using Hardener H-3615-S were examined for storage stability and physical properties of the cured product. In addition,
The numbers showing the composition in the table are the number of copies.

[0069]

[Table 1]

As shown in Products 1-1 to 1-3 of the present invention, the products of the present invention exhibited rubber-like elasticity, and the peel adhesion strength was remarkably improved as compared with the epoxy resin alone like Comparative Product 1-5. .. Further, when the blocked urethane was used alone like Comparative Product 1-4, it did not cure.

Example 2 Epoxy Resin, Blocked Isocyanate Compound-B and Dicyandiamide with ACR Hardener H-3615-
The storage stability and the physical properties of the cured product of the composition shown in Table 2 using S and S were examined.

[0072]

[Table 2]

Example 3 The physical properties of the cured product were examined for the composition shown in Table 3 using DCMU using an epoxy resin, a blocked isocyanate compound-A and sebacic acid dihydrazide or eicosane diacid dihydrazide.

[0074]

[Table 3]

Example 4 Epoxy resin, blocked isocyanate compound-C and adipic acid dihydrazide and dicyandiamide, ACR
The storage stability and the physical properties of the cured product of the composition shown in Table 4 using HARDNER H-3293S were examined.

[0076]

[Table 4]

Like Comparative Example 4-1, the oxime-based blocked isocyanate compound foamed during curing and did not have sufficient strength.

[0078]

As described above, the epoxy resin (I), the blocked isocyanate compound (II) and the latent curing agent (I
The curable epoxy blocked urethane composition containing the component II) is excellent in rubber-like elasticity, mechanical strength and adhesiveness as compared with a conventional one-pack latent curing type epoxy resin composition, and Compared with conventional oxime blocked urethane, it is superior in stability and especially in foamability of the cured product, and is useful as a structural adhesive sealing material, a chipping paint for automobiles and the like.

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[Procedure amendment]

[Submission date] April 9, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Title of invention

[Correction method] Change

[Correction content]

[Title of Invention] curable epoxy blocked urethane composition

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be amended] Claims

[Correction method] Change

[Correction content]

[Claims]

[Chemical 1] R₁-NH-R_Two  (In the formula, R₁Is a cycloalkyl group, R_TwoHas 1 carbon atom
A group selected from an alkyl group of ~ 9 and a cycloalkyl group,
R₁And R_TwoMay be the same or different)
(II-b), NCO / secondary monoamino group equivalent ratio
Block obtained by masking with 1 / 1.0 to 1 / 2.0
Dosocyanate compound (II) and latent curing agent (I
II) and a curable epoxy block containing essential componentsDoC
Retan composition.

Claims (1)

[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 prepolymer having an average molecular weight of 600 to 20,000
(II-a) is represented by the general formula: R ₁ —NH—R ₂ (wherein R ₁ is a cycloalkyl group, R ₂ is a carbon atom of 1 to 1).
A group selected from an alkyl group of 9 and a cycloalkyl group, R
₁ and R ₂ may be the same or different) (I
Ib), NCO / secondary monoamino group equivalent ratio 1/1.
A curable epoxy block urethane composition comprising a blocked isocyanate compound (II) obtained by masking with 0 to 1.0 and a latent curing agent (III) as essential components.