JPS5927914A - One-pack epoxy resin composition - Google Patents

Abstract

PURPOSE:The titled composition excellent in storage stability and curability, comprising a normally liquid epoxy resin, a specified adduct, and an isocyanato group-containing compound. CONSTITUTION:An epoxy compound (e.g., bisphenol A glycidyl ether epoxy resin) is added to an imidazole compound (e.g., 2-methylimidazole) or a carboxylate salt thereof in an amount to provide 0.8-1.5 epoxy groups per active hydrogen atom of the imidazole component, and the product is ground to obtain an adduct. Then, 100pts.wt. normally liquid epoxy resin having at least two epoxy groups in the molecule (e.g., bisphenol A glycidyl ether epoxy resin) is mixed with 1-15pts.wt. above-produced adduct and 0.1-10pts.wt. isocyanato group-containing compound (e.g., phenyl isocyanate). EFFECT:This composition cures at 100-120 deg.C in 30-60min into a cured product excellent in adhesiveness, strength, corrosion resistance, and electrical insulation.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel one-component epoxy resin composition. The object is to provide a one-component epoxy resin composition that has excellent storage stability and curability, provides a cured product with excellent performance, and can be easily manufactured. □Epoxy resin is used in adhesives, paints, laminations, etc. due to its excellent adhesion, strength, corrosion resistance, and electrical insulation properties.
It is used in many ways such as casting, but most of them are two-part type. In the two-component type, the epoxy resin and curing agent must be stored separately and mixed together as needed, making storage and handling complicated, and the pot life is limited, so large amounts cannot be used. They cannot be mixed in advance, and when used in large quantities, they have to be blended more frequently, which inevitably reduces efficiency.

In order to overcome these drawbacks, several liquid-type epoxy resin compositions have been proposed. for example,
There are products containing latent curing agents such as BF3 amine, complexes, dicyandiamide, organic acid hydrazide, and imidazole compounds, but these have excellent storage stability, but require high humidity for curing. Those that can be cured at relatively low temperatures have low storage stability and cannot be said to be practically satisfactory. In addition, there are epoxy resins and amine hardeners mixed together and immediately frozen to stop the reaction, amine hardeners microencapsulated and dispersed in epoxy resin, and monoregular seeds. There are products that adsorb the hardening agent to prevent contact between the hardening agent and the epoxy resin. Frozen type products are extremely expensive to manufacture and store. At present, microcapsule type products have insufficient capsule stability and high manufacturing costs, so they have not been put into practical use. Molecular sheep type products are unstable to moisture and are only used in special fields.

As described above, all of the single-wave epoxy resin compositions that have been proposed so far have practical difficulties. The appearance of things was highly desired.

The present inventors have conducted extensive research in order to develop a composition that can overcome the drawbacks of such conventional single-wave type epoxy resin compositions and can also fully utilize the advantages of the single-wave type epoxy resin composition. This is what led to the present invention.

That is, the present invention relates to a one-wave type epoxy resin composition containing the following three components (4), (B), and (C) as essential components.
It is something.

(4) Epoxy resin that is liquid at room temperature (B) An adduct of an epoxy compound and an imidazole compound or a carboxylic acid salt of an imidazole compound (a compound having a Cl isocyanate group) The epoxy resin (4) used in the present invention is liquid at room temperature. There is no particular restriction as long as it is a polyepoxy compound having 2 to 12 epoxy groups in one molecule. Examples of such compounds include glycidyl ether type epoxy resin of bisphenol A, glycidyl ether type epoxy resin of glycerin, etc. , polyalkylene oxide glycidyl ether type epoxy resin, oxybenzoic acid glycidyl ester ether type epoxy resin, dimer acid glycidyl ester type epoxy resin, phenol novolac glycidyl ether type epoxy resin, brominated bisphenol A glycidyl ether type epoxy resin , glycidyl ether type epoxy resin of bisphenol F, alicyclic type epoxy resin made by epoxidizing polybutadiene with peracetic acid, etc.Mixtures of the above epoxy resins and mixtures with monoepoxy compounds for lowering the viscosity of the epoxy resins. can also be used.

The epoxy compound used in the production of adduct CB) in the present invention may be a monoepoxy compound or a polyepoxy compound. ). Examples of the monoepoxy compound include butylglycidyl, leate, silane, xylglycidyl ether, phenylglycidyl ether, p-xylylglycidyl ether, glycidyl acetate, glycidyl butyrate, glycidyl hexonide 1-glycidyl benzoate, and the like. As a polyepoxy compound,
For example, the glycidyl ether type of 1-bisphenol A
Those mentioned above, such as glycidyl ether type epoxy resin and phenol novolac, can be used. Since the polyepoxy compound has more functional groups than the monoepoxy compound, it is possible to reduce the number of shells of component (B) in the wave-type epoxy resin composition, which is economically advantageous.

The imidazole compound used for producing the adduct (B) refers to one having an active hydrogen at the nitrogen position of the imidazole ring. For example, imidazole, λ-methylimidazole, neethylimidazole, -1ethyl-methylimidazole, neeisoprobylimidazole, 2-
Examples include phenylimita'zole and codedecylimidazole.

The above carboxylic acid salts of imidazole compounds are also adducts (B
) can be used for manufacturing. Acids that form such salts include, for example, acetic acid, lactic acid, salicylic acid, benzoic acid, adipic acid,
Examples include 7-talic acid, citric acid, tartaric acid, maleic acid, trimellitic acid, and the like.

The reaction ratio of the epoxy compound and the imidazole compound or the carboxylate of the imidazole compound in producing the adduct (B) is such that the number of epoxy groups is Og to 73 per 7 active hydrogens of the imidazole compound. Preferably d is /;7. -~/: /, ni. The addition reaction may be carried out without a solvent, but it is advantageous to dissolve the imidazole compound in a suitable solvent and drop the epoxy compound dropwise in terms of removing the reaction heat and reducing the viscosity. The solvent is preferably an aromatic or ketone solvent that is inert to the epoxy resin, such as toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, and the like. After the reaction is completed, the solvent is removed under reduced pressure, and the mixture is cooled and ground to a suitable particle size.

Compounds having an isocyanate group in the present invention (0 includes, for example, monoisocyanate compounds such as phenyl isocyanate and tolyl isocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, tolylene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, isopropylidenecyclohexyl isocyanate) , lysine isocyanate, adduct of tolylene diisocyanate and trimethylolpropane, adduct of tolylene diisocyanate and pentaerythritol, adduct of tolylene diisocyanate and polyethylene glycol, adduct of tolylene diisocyanate and polypropylene glycol, hexamethylene diisocyanate and Examples include polyisocyanate compounds such as polyethylene adipate prepolymers.

Cured polyisocyanate products are more preferred than monoisocyanate compounds.

The one-wave type epoxy resin composition according to the present invention can be easily produced by mixing the three components (A), (B), and (C) at room temperature. The three components may be mixed simultaneously, or any two components may be mixed first and then the remaining component may be mixed.

It is known that an adduct of an epoxy compound and an imidazole compound or a carboxylate of an imidazole compound is used as a curing agent for epoxy resin, but storage stability can be achieved by simply mixing this with a compound having an isocyanate group at room temperature. The inventors discovered for the first time that they were able to obtain a single-wave epoxy resin composition that exhibits properties far superior to those previously known, which cures well under short curing conditions at low temperatures. This is clearly what I found.

This composition cures the epoxy resin by the catalytic action of the tertiary amine of the adduct of the imidazole compound (or carboxylate of the imidazole compound) and the epoxy compound when heated, and the action mechanism of the compound having an isocyanate group is Although it is unclear, it is thought that it reacts with the hydroxyl group of the imidazole compound adduct and prevents the reaction of the imidazole compound adduct at room temperature. Even if the isocyanate group of a compound having an isocyanate group is directly involved in the curing reaction of the epoxy resin, it has only a secondary meaning.

The larger the amount of component (B) added to component (4), the faster the curing upon heating, but the higher the rate of increase in viscosity at room temperature. That is, storage stability is reduced.

Conversely, if the amount of component (B) added is small, curing upon heating will be slow and storage stability will be high. Preferably the ingredient is 70
Component (B) is preferably in the range of 7 to 75 parts by weight relative to 0 parts by weight. If the amount of component (p,
) It is preferable for component (C) to be in the range of 0/-10 times compared to too much times.

The composition is manufactured by mixing component (A), component (B) crushed to an appropriate particle size, component (0, and other components if desired), and thoroughly dispersing and kneading with a triple roll or the like. If the particle size of component (B) is small, curing will be faster when heated, but the storage stability at room temperature will be lowered, and if the particle size is large, the opposite will occur.Therefore, particle size control is also important. It is.

If desired, components such as an anti-settling agent, a diluent, a pigment, a filler, a plasticizer, and coal tar may be added to the composition to prevent precipitation of component (B). As an antisettling agent,
Silicic anhydride, kaolin, asbestos, attapulgide, talc,
Powder such as bentonite can be used.

Other curing agents can also be added to the composition, if desired. In this case, component (B) acts as an accelerator due to the action of its tertiary amine, which results in faster curing upon heating than when other curing agents are used alone, and ensures storage stability at room temperature. Other types of curing agents include, for example, ethylenediamine, diethylenetriamine, dicyandiamide, aliphatic polyamines such as daanidine, cycloaliphatic amines such as di(+-aminocyclohexyl)methane, isophoronodiamine, and m-phenylenediamine. , p, p'-bis-(aminophenyl)methane;
Phthalic anhydride, tetrahydroheptalic anhydride, hexahydrophthalic anhydride, methylated hexahydroheptalic anhydride,
Examples include polycarboxylic acid anhydrides such as trimellitic anhydride, phenol resins, melamine resins, urea resins, and the like.

In the present invention, a one-wave type epoxy resin composition can be easily obtained by simply kneading component (4), component (B), and component (C), and the composition has a strength of 6 months or more at room temperature. It can also be stored stably at 100~/10''C for 60 minutes~30 minutes.
It can be said that it is significantly superior to other single wave type epoxy resin compositions that have been proposed in the past in that it can be cured in minutes.

The cured product of the composition of the present invention exhibits excellent performance and can be utilized in a wide range of fields such as adhesives, paints, electrical insulating materials, and laminated structures.

Hereinafter, the present invention will be explained in more detail by giving examples, but the scope of the present invention is not limited by these examples. In the example, the part represents the Juho part.

Production example/[Production of component (B)] In a 31 glass flask equipped with a stirrer, a dropping device, and a funnel, add 2 pieces of methylimidazole 3θθv1 xylene 9
Add 009 and mix in mail bath /10~/
Melted by heating to 20"C. AE at 720°C.
R, 3,30 (trade name of bisphenol A diglycidyl ether type epoxy resin manufactured by Asahi Kasei Kogyo ■, epoxy equivalent/gs) qsoy was added dropwise over half an hour to carry out a reaction. In order to suppress heat generation during the reaction, the temperature of the bath was raised to 1.20'C and the reaction temperature was controlled at 1.20'C. The adduct produced was insoluble in xylene, so it was separated from the system.

The stirring was stopped, the upper layer of xylene was separated by tilting, and the remaining xylene was distilled off at a reduced pressure of 10 μHg F/lIO°C.
The mixture was poured out from the flask into a flat shallow dish under the A% condition and further dried for /gO''c/hour to obtain a dark red adduct.

Production Example 7 According to Production Example 1, various imidazole compounds and epoxy compounds were reacted with the combinations shown in Table 1 to obtain adducts.

(Left below) Table 1) Trade name of phenol novolac glycidyl ether type epoxy resin manufactured by Dow Chemical Company. Epoxy */qs
2) 2-Methylimidazole-yarichylate was prepared by adding λ-
It was produced by dissolving 39 pieces of methylimidazole, reacting with 417f of salicylic acid at room temperature, and removing the solvent under reduced pressure.

The adduct obtained in Example/Manufacturing Example/ was coarsely ground to approximately 211) mesh size and then finely ground to obtain three mesh bath powders. This powder and AER,? ,? / (trade name of bisphenol A diglycidyl ether type epoxy resin manufactured by Asahi Kasei Corporation), tolylene diisocyanate, and Attagel SO (trade name of Attapulguide powder manufactured by Hayashi Kasei Corporation) as an anti-settling agent were kneaded with a three-roll mill. Using this composition,
Table 2 shows the results of measuring the tensile shear adhesive strength and storage stability when bonding steel plates.

(Leaving space below) Example of production /''c Obtained adduct 31jt meshupus powder, /lrk, ?J/, dicyandiami 1゛, ?, 2
! Table 4 shows the results of measuring the storage stability and tensile shear adhesive strength using this composition by mixing Metshupas powder, tolylene diisocyanate, and Akugel 10 using a Miki roll. /) AER,? J/
Add other ingredients to the composition of the loo part and Akugel NOk part, 2) Seal the cap and leave it in an environment of 30"C1 or 2&"C, and wait for the number of days until it reaches a viscosity that cannot be stirred.3)'/! ; Steel plate when hardened at O"C for tio minutes -
Steel plate tensile shear adhesive strength AER,? ,? / 700 copies, 31! One part of λ-methylimidazole ground in a mesh bath, two parts of tolylene diisocyanate, and the left part of Akugel sO were kneaded with three rolls. When this composition was sealed and allowed to stand in a SO''C environment, it was completely cured in 6 hours, and it was found that the storage stability was significantly lower than that of the composition of the present invention.

Patent applicant: Asahi Kasei Industries, Ltd.

Claims (1)

[Claims] (1) A one-component epoxy resin composition containing the following three components (A), (B), and (C) as essential components. Epoxy resin that is liquid at room temperature (B) An adduct of an epoxy compound and an imidazole compound or a carbonate liquid salt of an imidazole compound (a compound having 0 isocyanate groups)