JP2835359B2 - Curing method for one-part compound - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for curing a one-part compound comprising an epoxy resin and a curing agent.

In particular, the present invention is a heat treatment at a relatively low temperature of about 60 to 70 ° C., or a relatively short time of about several minutes even at a temperature of 80 ° C. or more, as in the field of civil engineering, anticorrosion, or precision electronic components. Can be used in fields where it is desired to obtain desired curing properties.

The reason is that it is difficult to secure a heat source that can be heat-treated at high temperature for a long time in fields where outdoor work is relatively common, such as civil engineering and construction, and in the field of corrosion prevention. Because it is difficult to secure reliability.

(Prior art) In the field of civil engineering, corrosion protection, and precision electronic components, it has been customary to use a room temperature-curable two-part epoxy resin compound for the purpose of rapidly curing at a relatively low temperature. Met.

However, this two-part epoxy resin formulation requires complex steps such as weighing, mixing, and stirring immediately before use, lacks reliability due to mistakes in lightweight, and has an extremely short pot life, resulting in unstable quality. There are drawbacks such as the fact that it is difficult to exhibit the characteristics as designed and the loss of material is large. For this reason, it is extremely disadvantageous particularly when the construction period is long and an adhesive or a paint is frequently used, such as in the field of civil engineering and anticorrosion.

In order to overcome the above-mentioned disadvantages of two-part epoxy resin formulations, one-part epoxy resin formulations have been actively developed in recent years,
Some are commercially available. Typically, to cure a one-part epoxy resin formulation, at a temperature of 80 ° C or higher,
The method of heating for several hours was used.

However, it is extremely difficult to heat for several hours at a temperature of 80 ° C. or higher in fields where relatively outdoor work is mainly performed, such as civil engineering and construction and anticorrosion. On the other hand, even in the work field where exposure to a high-temperature environment for a long time, such as the assembly of precision electronic components, may damage the components, heat the adhesive at a temperature of 80 ° C or higher for a long time to cure the adhesive. It was virtually impossible to adopt a method to do so.

(Problems to be Solved by the Invention) The present invention provides a method for curing a one-component compound that can be applied outdoors even when a heat source cannot be secured for a long time or when the heat resistance of an adherend is low.

[Means for solving the problem]

That is, the present invention relates to the following: After heating a one-part composition comprising an epoxy resin and a curing agent at a work site to start a reaction between the epoxy resin and the curing agent, before the reaction rate reaches 50%, The present invention relates to a method for curing a one-part composition, which comprises leaving the composition at ambient temperature.

The term “environmental temperature” as used in the present invention refers to a temperature surrounding a work site where a one-component composition is applied. Therefore, in the field of civil engineering and anti-corrosion, it is generally the outdoor temperature, and in the assembly of precision electronic components and the like, it is generally the temperature of the room in which the work is performed.

The temperature at which the reaction between the epoxy resin and the curing agent can be initiated varies slightly depending on the composition of the one-part formulation, but is generally in the range of 60C to 70C.

According to the present invention, a good cured product can be obtained only by heating at a temperature higher than the temperature at which the reaction can be started and for a relatively short period of time, and then leaving it at ambient temperature. The heating time may be at most as long as the reaction rate reaches 50%, but if the reaction start temperature is 60 ° C to 70 ° C, heating for about 1 hour is sufficient, and heating is performed at a higher temperature. In this case, the heating time may be short. For example, when heating at a temperature of 150 ° C. to 200 ° C., it is sufficient to perform the treatment for several tens seconds to several minutes.

Conventionally, as a usual curing method of a one-part composition, a method of heating at 80 ° C. or more for several hours or more as described above is used, and in order to obtain desired curing characteristics, a temperature of 100 ° C. or more is further required. For several hours. Although there are rare cases where the composition is cured only at a temperature of 60 ° C. to 70 ° C., in such a case, a method of heating at 60 ° C. to 70 ° C. for several hours or more has been usual. From this point, the effect of the present invention can be seen.

The reaction rate in the present invention is a value obtained by calculation from a calorific value measured by a differential thermal analysis method (DSC method), and is calculated by the following method.

(However, A is the total calorific value (mj / mg) when the one-pack formulation is heated to 275 ° C. at a constant rate, and B is used to start the reaction by heating the one-pack formulation. This is the total calorific value (mj / mg) measured immediately after the measurement.) The calorific value was measured when the sample was heated from room temperature (about 25 ° C) to 300 ° C at a rate of 10 ° C / min. It was determined from the exothermic peak area.

In the present invention, the reacting composition is left at ambient temperature before the conversion reaches 50%. The reaction rate generally varies depending on the composition of the one-part formulation, the heating temperature equal to or higher than the reaction start temperature, and the heating time.

In the present invention, the heat treatment is preferably stopped before the reaction rate reaches 50%, and more preferably, when the reaction rate reaches 10% to 30%, the mixture is left at ambient temperature.

If the reaction rate exceeds 50%, normal heat curing conditions,
That is, it is within the range of heating at a temperature of 80 ° C. or more for several hours or more, and for applications that do not hinder using such heat curing conditions, it is possible to obtain a cured product according to the purpose. However, the energy consumption for curing is considerably large.

The present inventor has found that if the reaction is left at an ambient temperature after the start of the reaction, the subsequent reaction effectively proceeds and a good cured product is obtained. The time to reach the cured product varies. In general, the higher the ambient temperature, the shorter the time for which it is left to stand.

In particular, according to the method of the present invention, a cured product having small internal stress can be obtained. This is because, in the present invention, after the reaction is started, the curing reaction proceeds only by being left at the ambient temperature, so that the degree of shrinkage at the curing temperature is small, and the distortion generated inside the cured product is small. Conceivable. Small internal stress means that, for example, when used as an adhesive or sealant in the field of electric / electronic materials, the strain energy given to electric / electronic parts / elements is small,
It has a great effect of improving the reliability of the product.

In addition, the present invention is intended to obtain a good cured product by allowing the curing reaction to proceed simply by leaving it in a normal environment after the start of the reaction. An epoxy resin composition is known, and the curing reaction of the composition proceeds only by being left in an ordinary environment.

Thus, although both seemingly resemble, the present invention heated a highly stable one-part formulation that hardly reacts under normal circumstances to initiate the reaction between the epoxy resin and the curing agent. Thereafter, the method is completely different from the above-described method of curing the two-part epoxy resin compound of the room temperature curing type in that it is left in an environment.

In addition, the cured product obtained by the present invention has higher heat resistance than the cured product obtained by curing the room temperature curing type two-component epoxy resin composition, and has the characteristics of the heat curing type epoxy resin composition. ing.

As the one-component epoxy resin composition used in the present invention,
A conventionally known one-component epoxy resin compound is appropriately used. In particular, a specific master batch type curing agent described below can be preferably used, but in addition, a curing agent such as guanidines, hydrazides, and acid anhydrides can be mixed and used.

Also, if desired, commonly used extenders, reinforcing materials, fillers, pigments, organic solvents, reactive diluents, non-reactive diluents, modified epoxies, etc. can be added to the one-part epoxy resin formulation. .

The epoxy resin constituting the one-component composition used in the present invention may be any one having an average of two or more epoxy groups per molecule. For example, bisphenol A,
Polyhydric phenols such as bisphenol F, catechol and resorcin; or polyglycidyl ethers obtained by reacting polyhydric alcohols such as glycerin and polyethylene glycol with epichlorohydrin; or p-oxybenzoic acid and β-oxynaphthoic acid Glycidyl ether esters obtained by reacting hydroxyerbonic acid with epichlorohydrin; or polyglycidyl esters obtained by reacting polycarboxylic acid such as phthalic acid and terephthalic acid with epochlorohydrin; or 4,4'-diaminodiphenylmethane Glycidylamine compound obtained by reacting epichlorohydrin with m-aminophenol or the like; epoxidized novolak resin, epoxidized cresol novolak resin, epoxidized polyolefin Etc. including without being limited thereto.

A preferred epoxy resin is the diglycidyl ether of bisphenol A.

Next, the one-pack type epoxy resin composition preferably used in the present invention contains a master batch type curing agent described in JP-A-64-70523.

The components constituting the master batch type curing agent will be described in detail below.

In the master batch type curing agent, the curing agent (I) and the epoxy resin (B) are in a fixed ratio, for example, in a ratio of 10 to 50,000 parts by weight of the epoxy resin (B) to 100 parts by weight of the curing agent (I). , Are mixed.

First, the curing agent (I) will be described. The curing agent (I)
It comprises a core made of a powdery amine compound (A) and a shell made of a reaction product of the amine compound (A) and the epoxy resin (B).

The powdery amine compound (A) referred to herein is obtained by treating the powdery amine compound (a) having a tertiary amino group. The powdery amine compound (a) having a tertiary amino group has a tertiary amino group but has no primary and secondary amino groups, and examples thereof include the following.

(1) A reaction product of a compound having at least one primary amino group and / or a compound having a secondary amino group in a molecule with a carboxylic acid compound, a sulfonic acid compound, an isocyanate compound or an epoxy compound (a-1) However, those having a primary amino group or a secondary amino group in the molecule of the reaction product are excluded.

(2) Imidazole compound (a-2) The raw material of the reaction product (a-1) will be described.

As the compound having one or more primary amino groups in one molecule, any of an aliphatic primary amine, an alicyclic primary amine and an aromatic primary amine may be used.

Examples of the aliphatic primary amine include methylamine,
Examples include ethylamine, propylamine, butylamine, ethylenediamine, propylenediamine, fuxamethylenediamine, diethylenetriamine, triethylenetetramine, methanolamine, ethanolamine, propanolamine, and diethylaminopropylamine.

Examples of the alicyclic primary amine include cyclohexylamine, isophoronediamine, aminoethylpiperazine and the like.

As the aromatic primary amine, aniline, toluidine,
Examples thereof include diaminodiphenylmethane and diaminodiphenylsulfone.

As the compound having one or more secondary amino groups in one molecule, any of an aliphatic secondary amine, an alicyclic secondary amine, an aromatic secondary amine, an imidazole compound, and an imidazoline compound may be used.

Examples of the aliphatic secondary amine include dimethylamine, diethylamine, dipropylamine, dibutylamine, dipentylamine, dihexylamine, dimethanolamine, diethanolamine, and dipropanolamine.

Examples of the alicyclic secondary amine include dicyclohexylamine, N-methylpiperazine and the like.

Examples of the aromatic secondary amine include diphenylamine, phenylmethylamine, and phenylethylamine.

Examples of the imidazole compound include imidazole, 2-methylimidazole, 2-ethylimidazole, 2-isopropylimidazole, 2-dodecylimidazole,
-Undecylimidazole, 2-phenylimidazole, 2-heptadecylimidazole, 2-ethyl-4-
Methyl imidazole and the carboxylate salts of the imidazole compounds mentioned herein can be mentioned.

Examples of the imidazoline compound include 2-methylimidazoline, 2-phenylimidazoline, 2-undecylimidazoline, and 2-heptadecylimidazoline.

Examples of other raw materials of the reaction product (a-1) will be described below.

Carboxylic acid compounds: for example, succinic acid, adipic acid,
Sebacic acid, phthalic acid, danomeric acid, etc.

Sulfonic acid compound: for example, ethanesulfonic acid, p-
Toluenesulfonic acid and the like.

Isocyanate compound: for example, tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate,
Hexamethylene diisocyanate and the like.

Epoxy compound: Any of a monoepoxy compound, a diepoxy compound and a polyepoxy compound or a mixture thereof may be used.

Monoepoxy compounds include butyl glycidyl ether, hexyl glycidyl ether, phenyl glycidyl ether, allyl glycidyl ether, para-tert-butylphenyl glycidyl ether, ethylene oxide, propylene oxide, paraxylyl glycidyl ether, glycidyl acetate, glycidyl butyrate, glycidyl hexyl Ethates, glycidyl benzoates, epoxy resins and the like can be mentioned.

Examples of the diepoxy compound include divalent phenol compounds such as bisphenol A, bisphenol F, catechol, and resorcin; and divalent compounds such as ethylene glycol, propylene glycol, polyethylene glycol, polypropynine glycol, 1,4-butanediol, and neopentyl glycol. Alcohol compound; p-oxybenzoic acid,
hydroxycarboxylic acids such as β-oxynaphthoic acid; diglycidyl compounds obtained by reacting dicarboxylic acids such as phthalic acid, terephthalic acid, and hexahydrophthalic acid with epochlorohydrin; 3,4-epoxy-6-methylcyclohexylmethyl Alicyclic epoxy compounds such as -3,4-epoxy-6-methylcyclohexanecarboxylate and 3,4-epoxycyclohexylmethyl (3,4-epoxycyclohexane) carboxylate can be mentioned.

A preferred amine compound (a-1) is a reaction product of N-methylpiperazine or diethylaminopropylamine with an epoxy compound. One equivalent of an active hydrogen atom of a second amine is reacted with one equivalent of epoxy of an epoxy compound. It can be obtained by

Examples of the imidazole compound (a-2) include 1-cyanoethyl-2-undecyl-imidazole-trimellitate, imidazolyl succinic acid, 2-methylimidazole succinic acid, 2-ethylimidazole succinic acid, 1-cyanoethyl-2-methylimidazole, -Cyanoethyl-
2-undecylimidazole, 1-cyanoethyl-2-
Phenylimidazole and the like can be mentioned.

As a preferred amine compound (a), a primary or secondary amine and an epoxy-containing compound are used in an amount of from 0.8 to 1.2 of an epoxy group of the epoxy compound based on 1 equivalent of an active hydrogen atom of the amine compound.
Products obtained by reacting at equivalent ratios are mentioned.

Among these amine compounds (a), ease of curing,
In order to obtain a product having particularly excellent storage stability, an imidazole derivative having one or more hydroxyl groups in one molecule is preferable.

Further preferred amine compounds used are compounds having at least two hydroxyl groups in the molecule, formed by the reaction of the imidazole compound with a compound having at least two epoxy groups in the molecule. As such an imidazole derivative, for example, an imidazole compound or a carboxylate of the imidazole compound;
An addition compound of a compound having one or more epoxy groups in one molecule is exemplified. Examples of the imidazole compound used include imidazole, 2-methylimidazole,
Examples thereof include ethylimidazole, 2-ethyl-4-methylimidazole, 2-isopropylimidazole, 2-undecylimidazole, 2-phenylimidazole, and carboxylate thereof.

Examples of the carboxylic acid include acetic acid, lactic acid, salicylic acid, benzoic acid, adipic acid, phthalic acid, citric acid, tartaric acid, maleic acid, trimellitic acid, and the like.

Compounds having one or more epoxy groups in one molecule include butyl glycidyl ether, hexyl glycidyl ether, phenyl glycidyl ether, p-xylyl glycidyl ether, glycidyl acetate, glycidyl butyrate, and glycidyl hexoyl. Monoepoxy compounds such as ate, glycidyl benzoate, allyl glycidyl ether, pt-butylphenyl glycidyl ether, ethylene oxide and propylene oxide, and epoxy resins are exemplified.

In order to obtain excellent curability and storage stability, it is necessary to use 2-methylimidazole or 2-methylimidazole as the imidazole compound.
One selected from -ethyl-4-methylimidazole or a mixture thereof is preferable, and the epoxy compound is most preferably an epoxy resin obtained by reacting bisphenol A with epichlorohydrin.

This adduct of the imidazole compound and the epoxy compound can be obtained by reacting 1 to 5 mol of the imidazole with 1 to 5 mol of the epoxy compound by a conventionally known general method.

The average particle size of the powdery amine compound (A) having a tertiary amino group is not particularly limited. However, if the average particle size is too large, the curability is reduced or the mechanical properties of the cured product are reduced. May be impaired. Preferably, the average particle size does not exceed 50 μm, and if the average particle size is further increased, the cured product will have reduced chemical resistance and mechanical strength. Optimally it should not exceed 10μ.

The purpose of excluding those having a primary amino group or a secondary amino group in the powdered amine compound (A) used is to mix a compound having these groups with an epoxy resin, especially a liquid epoxy resin. This is to prevent the viscosity of the compound from becoming extremely high.

The powdery amine compound (A) constituting the master batch type curing agent contains 1630 to 1680 cm ^-1 and 1680 to 1725 cm
Those having a bonding group (x) or (y) that absorbs infrared light of ^-1 are preferably used, and they can be measured using an infrared spectrophotometer. A Fourier transform infrared spectrophotometer By using, more detailed analysis can be performed.

Of the bonding group (x) having an absorption of 1630 to 1680 cm ⁻¹ ,
A particularly useful one is a urea bond.

Of the bonding group (y) having an absorption of 1680 to 1725 cm ⁻¹ ,
Particularly useful are the burette bonds.

The urea bond and buret bond are formed by the reaction of an isocyanate compound with water or an amine compound having one or more primary amino groups in one molecule.

As an isocyanate compound used to generate a urea bond represented by the bonding group (x) and a burette bond represented by the formula (y), any compound having one or more isocyanate groups in one molecule can be used. Although it is good, it is preferable to use a compound having two or more isocyanate groups in one molecule.

Representative isocyanate compounds include aliphatic diisocyanates, alicyclic diisocyanates, aromatic diisocyanates, and aliphatic triisocyanates.

Examples of the aliphatic diisocyanate include ethylene diisocyanate, propylene diisocyanate, butylene diisocyanate, and hexamethylene diisocyanate.

Examples of the alicyclic diisocyanate include isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, and the like.

Examples of the aromatic diisocyanate include tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, xylylene diisocyanate, and polymethylene polyphenyl polyisocyanate.

Examples of the aliphatic triisocyanate include 1,3,6-triisocyanatomethylhexane and the like.

Further, an adduct of the above isocyanate compound and a compound having a hydroxyl group in one molecule, for example, a reaction product of an isocyanate compound and α, ω-dihydroxyalkane, or a reaction product of an isocyanate compound and a bisphenol may also be used. Can be. Pre-reaction products of isocyanate compounds with water can also be used.

Examples of the amine compound having one or more primary amino groups in one molecule for forming a urea bond or a burette bond, which are representative of the bonding groups (x) and (y), include aliphatic amines and alicyclic amines. , Aromatic amines can be used.

Examples of the aliphatic amine include alkylamines such as methylamine, ethylamine, propylamine and butylamine; alkylenediamines such as ethylenediamine, propylenediamine, butylenediamine and hexamethylenediamine; diethylenetriamine, triethylenetetramine, tetraethylenepentamine and the like. Polyalkylene polyamines can be mentioned.

Examples of alicyclic amines include cyclopropylamine,
Examples thereof include cyclobutylamine, cyclopentylamine, cyclohexylamine, and isophoronediamine.

Examples of the aromatic amine include aniline, toluidine, benzylamine, naphthylamine, diaminodiphenylmethane, diaminodiphenylsulfone, and the like.

In the powdered amine compound (A), the bonding group (x) and the bonding group (y) are 1 to 1000 meq / Kg and 1 to 1000 meq / Kg, respectively.
It preferably has a concentration in the range of ~ 1000 meq / Kg. When the concentration of the bonding group (x) is lower than 1 meq / Kg, the compound (A) has insufficient mechanical strength, so that the working life of the compound is short.

Also, if it is higher than 1000meq / Kg, the curability will be poor,
It is not practical because high temperature curing is required. A more preferred concentration range of the binding group (x) is 10 to 300 meq / Kg.

When the concentration of the bonding group (y) is lower than 1 meq / Kg, the pot life of the compound is short because the mechanical strength of the compound (A) is not sufficient. On the other hand, if it is higher than 1000 meq / Kg, the curability is poor and high temperature curing is required, which is not practical. A more preferable range of the bonding group (y) is 100 to 200 meq / Kg.

The powdered amine compound (A) is preferably a compound having a wave number of 1730 to 1755 in addition to the bonding group (x) and the bonding group (y).
It has a bonding group (z) that absorbs infrared rays of cm ⁻¹ .

Among these bonding groups (z), particularly useful ones are carbonyl groups such as urethane bonds. This urethane bond is
It is produced by the reaction between an isocyanate compound and a compound having one or more hydroxyl groups in one molecule.

Examples of the compound having one or more hydroxyl groups in one molecule used for generating a urethane bond, which is a representative of the bonding group (z), include an aliphatic saturated alcohol, an aliphatic unsaturated alcohol, an alicyclic alcohol, and an aromatic alcohol. Alcohol compounds such as aliphatic alcohols; phenol compounds can be used.

As aliphatic alcohols, methyl alcohol, ethyl alcohol, propyl alcohol, butyl alcohol, amyl alcohol, hexyl alcohol, heptyl alcohol, octyl alcohol, nonyl alcohol,
Monoalcohols such as decyl alcohol, undecyl alcohol, lauryl alcohol, dodecyl alcohol, stearyl alcohol, eicosyl alcohol; ethylene glycol such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol monohexyl ether Monoalkyl ethers and the like can be mentioned. Other dihydric alcohols such as ethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, 1,3-butanediol and neopentyl glycol; trihydric alcohols such as glycerin and trimethylolpropane; tetrahydric alcohols such as pentaerythritol Can be mentioned.

Examples of the aliphatic unsaturated alcohol include allyl alcohol, crotyl alcohol, propargyl alcohol and the like.

Examples of the alicyclic alcohol include cyclopentanol and cyclohexanol.

Examples of the aromatic alcohol include monoalcohols such as benzyl alcohol and cinnamyl alcohol.

These alcohols may be primary, secondary or tertiary. Further, a compound obtained by reacting a compound having one or more epoxy groups in one molecule with a compound having one or more hydroxyl groups, carboxyl groups, primary or secondary amino groups, and mercapto groups in one molecule. A compound having one or more graded hydroxyl groups in one molecule can also be used as the alcohol compound.

Examples of the phenol compound include monohydric phenols such as carboxylate, cresol, xylenol, carvacrol, thymol, and naphthol; dihydric phenols such as catechol, resorcin, hydroquinone, bisphenol A and bisphenol F; and trihydric phenols such as pyrogallol and phloroglucin. be able to.

The compound having one or more hydroxyl groups in one molecule is preferably an alcohol compound or a phenol compound having two or more hydroxyl groups.

The preferred concentration range of the binding group (z) of the powdery amine compound (A) is 1 to 200 meq / Kg. When the concentration of the linking group (z) is lower than 1 meq / Kg, the working life of the compound is short. On the other hand, if it is higher than 200 meq / Kg, the curability is poor and curing conditions at a high temperature are required, which is not practical. A more preferred concentration range of the binding group (z) is 5 to 100 meq / Kg.
It is.

The concentration ratio of the binding group (z) to the total concentration of the binding group (x) and the binding group (y) Is preferably in the range of 0.05 to 1.0. When the concentration ratio is less than 0.05, the cohesive strength of the compound (B) becomes strong, and it is necessary to set the curing temperature higher than the practical range. Poor storage stability of the formulation and reduced resistance to mechanical shear.

The quantification of the concentration of the bonding group (x) and the bonding group (y) is performed by using the model compounds represented by the formulas (1) and (2) having the respective bonding groups and the bonding group (x) and the bonding group (y). After preparing a calibration curve using a standard substance having a functional group that absorbs infrared rays having a specific wavelength without performing the above, the standard substance and the powdered amine compound (A) are mixed at a certain ratio, and the mixture is mixed. Infrared absorption intensity, i.e., 1630-1680cm
The absorption intensity at ^-1 and 1680 to 1725 cm ^-1 may be measured, and the concentration may be calculated from the calibration curve. Examples of reference materials are 2,3-
Dimethyl-2,3-dicyanobutane can be mentioned,
The absorption intensity of this material based on cyano groups present at 2220-2250 cm ^-1 can be used.

In addition, the quantification of the bonding group (z) was performed using the model compound represented by the formula (3) in the same manner as the bonding group (x) and the bonding group (y).
It can be performed using 2,3-dimethyl-2,3-dicyanobutane.

The epoxy resin (B) used in the present invention is not particularly limited as long as it has two or more epoxy groups per molecule on average. For example, polyhydric phenols such as bisphenol A, bisphenol F, catechol, and resorcin; or polyglycidyl ether obtained by reacting polyhydric alcohol such as glycerin or polyethylene glycol with epochlorohydrin; or p-oxybenzoic acid; a glycidyl ether ester obtained by reacting a hydroxycarboxylic acid such as β-oxynaphthoic acid with epichlorohydrin; or a polyglycidyl ester obtained by reacting a polycarboxylic acid such as phthalic acid or terephthalic acid with epichlorohydrin; or Glycidylamine compounds obtained by reacting epichlorohydrin with 4'-diaminodiphenylmethane, m-aminophenol, etc .; furthermore, epoxidized novolak resins, epoxidized cresol novolaks Butter, although epoxidized polyolefin, and the like,
It is not limited to these. A preferred epoxy resin is the diglycidyl ether of bisphenol A.

As a method for producing a masterbatch type curing agent, for example, a powdery compound (a) having a tertiary amino group is dispersed in advance in an epoxy resin (B), an isocyanate compound is added thereto, and the mixture is added in the presence of water. To carry out the reaction. By this reaction, a shell can be formed on the surface of the core. The concentration of the binding groups (x), (y) and (z) in the powdery amine compound (A) as the core is adjusted by adjusting the amount of water to the compound (a) having a tertiary amino group. It can be carried out by changing the amount of the imissocyanate compound relative to the compound (a) and the type of isocyanate.

In order to previously disperse the powdery compound (a) having a tertiary amino group in the epoxy resin (B), it is preferable to mix while applying a mechanical shearing force such as a three-roll.

The epoxy resin (B) is selected from the above epoxy resins (B).

The average thickness of the shell covering the surface of the core made of the powdery amine compound (A) is preferably 50 to 10,000 °. Five
If the temperature is 0 ° or less, the pot life is not sufficient, and if it is 10000 ° or more, the curing temperature becomes too high, which is not practical. The thickness of the layer referred to here is observed with a transmission electron microscope. A particularly preferred shell thickness is 100 to 1000 ° in average layer thickness.

The epoxy resin (B), which is an essential component of the master batch type curing agent, has a role as a medium for reacting the compound (a) having a tertiary amino group with an isocyanate compound in the presence of water. However, the epoxy resin (B) also has a positive role in that a part of the epoxy resin (B) reacts with the powdery amine compound (A) to form a shell, thereby improving the storage stability as a curing agent. I have.

The weight ratio of the powdery amine compound (A) to the epoxy resin (B) is in the range of 1 / 0.1 to 1/500. If it is larger than 1 / 0.1, the powdery amine compound (A) cannot be dispersed in the epoxy resin (B). If less than 1/500,
Does not exhibit performance as a curing agent. Preferably 1/1 to 1/5
It is.

The master batch type curing agent is in a liquid or paste form at room temperature.

The mixing ratio of the master batch type curing agent is preferably 2 to 60 parts by weight based on 100 parts by weight of the epoxy resin used.

Examples and Comparative Examples Hereinafter, the present invention will be described with reference to examples, but the scope of the present invention is not limited by these examples. In addition, "part" in an example shows a weight part.

Reference Example 1 (Synthesis of powdery amine compound (A)) 1 mol of bisphenol A type epoxy resin AER-330 (manufactured by Asahi Kasei Kogyo Co., Ltd., epoxy equivalent: 185) and 1.5 mol of 2-methylimidazole were added in methanol and toluene. 80 ℃
After the reaction, the solvent is distilled off under reduced pressure,
A solid compound was obtained.

This was pulverized to obtain a powdery amine compound X-1 having an average particle size of 5 μm.

Reference Example 2 (Synthesis of Compound Having Bonding Groups x, y, z) One mole of diphenylmethane diisocyanate was previously reacted with 0.5 mole of hexamethylenediamine, and 0.75 mole of bisphenol A was added thereto, followed by further reaction. Thus, polymer P was obtained.

Reference Example 3 (Creation of calibration curve) 2,3-dimethyl-2,3-dicyanobutane was used as a standard substance, and this was used as a model compound (M1). From the actual weight ratio and the model compound (M1) 1630-16
The area of the absorption band of 60cm ^-1, and a calibration curve relating the area ratio of the absorption band of the standard substance 2220~2250cm ^-1. The result is shown in FIG.

That is, the vertical axis represents the weight ratio of the model compound (M1) to the standard substance, and the horizontal axis represents the weight ratio of the model compound (M1) from 1630 to 1660.
Taking the area ratio of the absorption band of cm ^-1 to the area of the standard substance and plotting the measured values show that there is a linear relationship between the weight ratio and the area ratio.

Similarly, model compound (M2) Absorption band area of 1680-1725cm ^-1 and model compound (M3) 1730-1755cm ^-1 absorption band area and 2220-2250 standard material
A calibration curve was created to relate the area ratio of the absorption band at cm ^-1 to the actual weight ratio. The results are also shown in FIG.

The method for determining the concentration of each binding group per weight of the measurement sample from FIG. 1 is as follows.

That is, a precisely weighed measurement sample and a standard substance are mixed, and from the IR chart, 1630 to 1660 cm ⁻¹ , 1680 to 1725 cm ⁻¹ ,
The peak areas at 1730-1755 cm ^-1 and 2220-2250 cm ^-1 are determined. From this area, the area ratio of each, that is, 1630-16
Peak area ratio of 60cm- ¹ and 2220-2250cm- ¹ , 1680-1725cm
^-1 and the peak area of 2220～2250Cm ^-1 ratio and 1730～1755Cm ^-1
And a peak area ratio of 2220 to 2250 cm ⁻¹ , and a straight line corresponding to each peak from FIG. 1, for example, 1630 to 1660 cm ⁻¹
In the case of, the weight ratio of the model compound (M1) / standard substance is determined using a straight line for the model compound (M1).

From this weight ratio, the urea group equivalent of the model compound (M1) /
By converting to the reference material weight,
The binding group equivalent having an absorption between 1630 and 1660 cm ^-1 is determined. By dividing the obtained binding group equivalent by the weight of the measurement sample, the concentration of the binding group per measurement sample weight can be obtained. A similar method may be used for other absorptions.

The IR spectrum was measured using FT manufactured by JEOL Ltd.
-IR (JIR-100) was used.

Reference Example 4 (Synthesis of a master batch type curing agent) 1 g of the polymer P obtained in Reference Example 2 was dissolved in 99 g of a mixed solvent of xylene / methanol (1/1). To this solution was added 50 g of 1-cyanoethyl-2-phenylimidazole (2PZ-CN), which had been previously pulverized to an average of 5 μm,
After stirring for minutes, the mixture was filtered immediately, the cake was separated by filtration, and the mixed solvent was evaporated from the cake at 50 ° C. under a reduced pressure of 5 to 10 mmHg. At that time, the nonvolatile content in the filtrate was measured to be 0.3% by weight, and the remaining 0.7% by weight was 2PZ-CN
Is attached to

10 g of the powdery compound thus obtained is taken, and AER
Add 20 g of -331 (bisphenol A type epoxy resin, manufactured by Asahi Kasei Corporation, epoxy equivalent: 189), mix uniformly using a three-roll mill, and prepare a master batch type curing agent H-1.
30g was obtained. Masterbatch type curing agent H-1 obtained
Had a viscosity of 220,000 cps (25 ° C.). Further, the viscosity after being left for one week in an atmosphere of 40 ° C. was 250,000 cps, and there was almost no change in viscosity.

Reference Example 5 (Synthesis of master batch type curing agent) In one separable flask equipped with a stirrer and a temperature detector, 400 g of AER-331 and 20 g of powdered amine compound X-1 were added.
After adding 0 g and 5 g of water and mixing uniformly, 18 g of tolylene diisocyanate (TDI) was added and the reaction was continued for 2 hours while stirring at 40 ° C. A mold curing agent H-2 was obtained.

(Analysis of the master batch type curing agent) 15 g of the master batch type curing agent H-2 was converted to 100 g of xylene.
And the mixture was allowed to stand for a day and a night, and a component insoluble in xylene was precipitated. When this precipitate was separated by filtration, 5.6 g
A precipitate was obtained. Xylene was dried under reduced pressure from the filtrate, and the remaining viscous liquid was identified as ART-331 by IR analysis and measurement of epoxy equivalent by the KI-HCL method.

On the other hand, the precipitate was dried at 40 ° C. under reduced pressure to obtain a sample for analysis. 3.3 g of this analytical sample was
-Dimethyl-2,3-dicyanobutane (10 mg) was added, and the mixture was pulverized and mixed in a mortar. Then, 2 mg of the mixture was pulverized together with 50 mg of KBr, and tablets having a diameter of 8 mmφ were prepared using a tablet molding machine.

Using this tablet, JIR-100 JIR-100 FT-
An infrared spectrum was obtained with an IR measurement device. The concentration of the binding group (x) was determined using a calibration curve prepared in advance from a spectrum diagram in the infrared wavelength region of 1500 to 1800 cm ⁻¹ in the obtained diagram, and was found to be 55 meq / Kg-powder amine compound. there were.

1680~1725cm in the same manner the absorption wavelength region in the wavelength region and 1730～1755Cm ^{-1 -1,} was determined the binding group (y), binding group (z), respectively 25 meq / Kg, in 15 meq / Kg there were.

To 30 g of the present hardener H-2, 100 g of AER-331 and 40 g of Epomate B-002 (hardener manufactured by Yuka Shell Co.) were added, and 25
Cured at ℃ to make a sample for electron microscope. The sample was sliced, and a cross section was photographed with a transmission electron microscope, and the result is shown in FIG. FIG. 2 shows that a shell is formed.

Examples 1 to 10 100 g of AER-331 (bisphenol A type epoxy resin, manufactured by Asahi Kasei Corporation) was added with 25 parts of master batch type curing agent H-1.
g and coarse kneading in advance, then use a three roll
The mixture was uniformly mixed at a discharge rate of g / min to produce a one-part compound F-1.

The viscosity of F-1 of the obtained blended product is 21,000 cps (25 ° C.)
Met.

Mild steel sheet-Mild steel sheet SPCCG (JISG3
141) Adhesive sample, paint film for pencil hardness measurement (thickness 300μ)
m), a sample for DSC measurement and a sample for internal stress measurement were prepared, and three conditions of 2 ° C., 25 ° C., and 40 ° C. were set as environmental temperatures.
Table 1 shows the characteristics of the cured product obtained when the three conditions of 60 ° C., 70 ° C., and 200 ° C. were combined as the heat treatment temperature, and the product was left at ambient temperature after the heat treatment.

 The internal stress was measured by the following method.

A phosphor bronze for spring having a thickness of 0.2 mm, a width of 13 mm, and a length of 18 mm was used as a metal piece for measuring internal stress, and the above-mentioned compound F-1 was added to the metal piece.
What was applied and cured to a thickness of 5 mm was used as a sample for internal stress measurement.

The sample was heated at a rate of 10 ° C./min, kept at 200 ° C. for 10 minutes to release the strain, and then gradually cooled. The strain during this temperature cycle was measured using a stress measuring device using an optical strain sensor as shown in FIG.

 The principle of the measurement method and the analysis method will be described below.

This measurement method is a so-called bimetal method in which a residual stress is calculated from a change in curvature of a metal strip having a sample coated on one surface, and an internal stress σ is obtained by the following equation.

Here, l: fulcrum distance, b: width of sample strip, δ ₁ : deflection at the center between fulcrums due to internal stress, δ ₂ : deflection when a small load w is applied to the same position, h ₁ : coating film Thickness, h ₂ : thickness of the metal plate.

The operating principle of the optical strain sensor shown in FIG. 3 is as follows.

That is, the light of a light emitting diode (LED) is finely focused through a lens, and the light is irradiated on the object (sample) 1,
The diffused reflected light is imaged as a spot on a light position detecting element (sensor) by a light receiving lens. When the object is displaced, the spot moves, and the amount of movement is substantially proportional to the displacement of the object. The position of the spot is converted into an electric signal by the light position detecting element, and an arithmetic circuit in the controller 4 outputs a displacement output irrelevant to the reflectance of the target object, and causes the recorder 3 to record the output.

Comparative Examples 1 to 6 A heat treatment was carried out using the same one-part compound F-1 as used in Examples 1 to 10, and after the reaction rate exceeded 50%, the mixture was allowed to stand at ambient temperature. Table 2 shows the properties of the cured product.

As is clear from Tables 1 and 2, it was found that the use of the curing method of the present invention can provide a cured product having good properties even if left alone after the reaction is initiated. .

Examples 11 to 17 After the same compound F-1 as used in Examples 1 to 10 was allowed to stand at 50 ° C. for 7 days, in the same manner as in Examples 1 to 10, a soft steel sheet-mild steel sheet adhesion sample was used. , Pencil hardness measurement coating (thickness
Table 3 shows the results of preparing and evaluating a sample for measuring DSC and DSC.

The viscosity of the F-1 compound after standing at 50 ° C. for 7 days is 30,000 cp
s (25 ° C.).

Comparative Example 7 To 100 g of AER331 used in Examples 1 to 10, 2-ethyl-
Formulation F-2 produced by the mixing method of Examples 1 to 10 to which 5 g of 4-methylimidazole (2E4MZ) was added.
Was added to 100 g of AER331, and 5 g of N, N'-benzyldimethylamine (BDMA) was added.
When the compound F-3 produced by the mixing method performed in step 5 was left at 50 ° C., both the compounds gelled after one day.

As a result, it can be seen that the one-part formulation of the present invention exhibits excellent storage stability, and sufficiently exhibits the effects of the present invention even after storage.

Example 18 and Comparative Examples 8 and 9 Using the same compound F-1 as used in Examples 1 to 10 and a two-part epoxy resin compound as a comparative example, a cured product was prepared, and heat resistance was determined. Was evaluated. Compound F-2 of Comparative Example 8 was used. Compound F-4 of Comparative Example 9 was AER-3
31 11.5 g of triethylenetetramine (TETA) was added to 100 g, and produced by the mixing method performed in Examples 1 to 10.

The above three blends were cured by the method shown in Table 4, and the obtained cured product was cut into a size of 30 mm in length, 2 mm in length and 2 mm in width, and a vibron III type (manufactured by Toyo Baldwin Co., Ltd.)
The temperature at which the peak of tan δ was measured from room temperature to 250 ° C. at a rate of 3 ° C./min was defined as Tg.

From the results in Table 4, it can be seen that the cured product obtained by the present invention is a good cured product having a high elastic modulus, but in the case of the comparative example, it is a cured product having low heat resistance.

Examples 19 to 20 8 g of dicyandiamide was added to 100 g of AET-331 (bisphenol A type epoxy resin, manufactured by Asahi Kasei Corporation), and the mixture was coarsely kneaded beforehand. The mixture was mixed to produce a one-part compound F-5. Mild steel sheet-Mild steel sheet SPCCG (JISG-3141) using the above compound
Make an adhesive sample and a DSC measurement sample at 150 ° C
Table 5 shows the properties of the cured product obtained when the reaction was started by heating for 45 minutes and then left at 25 ° C. and 40 ° C. ambient temperature.

(Effects of the Invention) As described above, in the present invention, after the epoxy resin-based one-part compound is heated to start the reaction, when a specific reaction rate is reached, it is simply left at ambient temperature. By the operation, the compound can be easily cured even at an outdoor work site.

[Brief description of the drawings]

FIG. 1 is a graph showing the relationship between the weight ratio of a model compound to a standard substance and the area ratio of an IR chart in Reference Example 3. FIG. 2 is an electron micrograph showing the particle structure (drawing) of the master batch type curing agent obtained in Reference Example 5. FIG. 3 is a schematic diagram of an internal stress measuring device using an optical strain sensor. 1: sample, 2: sensor, 3: temperature controller, 4: recorder,

Claims (1)

(57) [Claims] (1) heating a one-part composition comprising an epoxy resin and a curing agent at a work site to initiate a reaction between the epoxy resin and the curing agent, and before the reaction rate reaches 50%, A method for curing a one-part composition, comprising leaving the composition at ambient temperature.