JPH1180322A - Extension of pot life of epoxy resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing the subject composition of extended pot life, low in effect of retarded setting and toxicity by including a compound, produced by the Michael addition reaction between a polyamino compound and unsaturated carboxylic acid ester, as the hardening agent. SOLUTION: This composition of extended pot life is obtained by including a product of the Michael addition reaction as the hardening agent, the reaction being effected between (A) a polyamino compound, preferably a diamine compound shown by the formula H2 N-H2 C-A-CH2 -NH2 (A is phenylene or cyclohexylene), e.g. meta-xylylene diamine and (B) at least 0.1 mols, per mol of the polyamino compound above, of an unsaturated carboxylic acid ester, preferably acrylic acid or methacrylic acid ester shown by the formulae R<1> -CH= CR<2> -COOR<3> (R is H, CH3 or the like; R2 is H or CH3 ; and R is a 1-20C hydrocarbon), at room temperature to 150 deg.C for 5 to 50 h.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for extending the pot life of an epoxy resin composition containing an epoxy resin and a polyamine-based curing agent as main components.

[0002]

2. Description of the Related Art Various polyamino compounds are used as epoxy resin curing agents and raw materials thereof. Particularly, an epoxy resin composition using an aliphatic polyamino compound and an epoxy resin curing agent for room temperature curing using the same as a raw material,
It is used in paints, flooring materials, lining materials, adhesives, etc. in a very wide range of fields such as ships, automobiles, civil engineering and construction. Among the above aliphatic polyamino compounds, diamines (xylylenediamine, bisaminomethylcyclohexane, etc.) in which two aminomethyls are added to an aromatic ring or an alicyclic group and an epoxy resin curing agent using the same as other materials are other Compared with an aliphatic polyamino compound and an epoxy resin curing agent using the same as a raw material, it provides a cured product having excellent curability, giving a coating film excellent in gloss and smoothness, and having excellent water resistance and chemical resistance. And so on. However, the diamine and an epoxy resin curing agent using the diamine as a raw material,
Due to the high reactivity with the epoxy resin, the epoxy resin composition has the disadvantages of short pot life and poor workability.

It has been known that a cyanoethylated polyamino compound obtained by a Michael addition reaction of a polyamino compound with acrylonitrile extends the pot life of an epoxy resin composition (for example, edited by Hiroshi Kakiuchi, "New Epoxy Resin") 186, (1985)). However, when the above cyanoethylated polyamino compound is used, there is a disadvantage that the curing speed of the epoxy resin composition is also slow. Acrylonitrile is specified as a specific chemical substance and a deleterious substance. Furthermore, a cyanoethylated polyamino compound obtained by a Michael addition reaction of a polyamino compound and acrylonitrile is an organic cyanide compound specified as a deleterious substance and containing the same. It falls under the category of “formulation” and is highly toxic. For this reason, from the viewpoint of safety and health, restrictions on these handling have been increasing in recent years.

JP-A-8-269196 relates to a method for producing a star-shaped or comb-shaped branched aliphatic polyamino compound and a curable resin composition, and arbitrarily controls the pot life after mixing with another resin system. An aliphatic polyamino compound which can be used and a curable resin containing the same as one component are disclosed. However, an aliphatic polyamino compound having a low viscosity at room temperature has a small pot life extending effect.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an epoxy resin composition which uses a low-viscosity liquid polyamino compound at room temperature, has a small effect of slowing down the curing rate of the epoxy resin composition, and has low harm. An object of the present invention is to provide a method for extending a pot life which is effective in room temperature curing.

[0006]

Means for Solving the Problems As a result of intensive studies on the above-mentioned problems in the epoxy resin composition, the present inventors have found that an epoxy resin composition cured at room temperature is incompatible with a low-viscosity liquid polyamino compound at room temperature. By using a compound obtained from the Michael adduct with a saturated carboxylic acid ester compound, it has the same pot life extension effect as a cyanoethylated polyamino compound, the effect of slowing the curing speed is small, and the harmfulness is low. Found and arrived at the present invention.

That is, the present invention is a method for extending the pot life of an epoxy resin composition, which comprises using a compound obtained by a Michael addition reaction between a polyamino compound and an unsaturated carboxylic acid ester compound.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION As the polyamino compound in the present invention, a diamine represented by the following formula (I) is preferably used.

Embedded image _{H 2 N-H 2 C-} A-CH 2 -NH 2 (I) (A denotes a phenylene group or a cyclohexylene group)

The diamine represented by the formula (I) used in the present invention includes orthoxylylenediamine, metaxylylenediamine, paraxylylenediamine, 1,2-bis (aminomethyl) cyclohexane, 1,3- Bis (aminomethyl) cyclohexane, 1,4-bis (aminomethyl) cyclohexane and the like can be mentioned. Among them, particularly preferred are metaxylenediamine, 1,3-bis (aminomethyl)
Cyclohexane. In the diamine represented by the formula (I), other polyamino compounds can be mixed and used in a range of less than 0.5 mol per mol.

The polyamino compound used by mixing with the diamine represented by the formula (I) includes ethylenediamine, diethylenetriamine, triethylenetetramine,
Aliphatic polyamines such as hexamethylene diamine and polyoxyalkylene polyamine; alicyclic polyamines such as isophorone diamine, norbornane diamine, 1,4-diaminocyclohexane and di (aminocyclohexyl) methane; metaphenylenediamine, diaminodiphenylmethane, diaminodiphenylsulfone And heterocyclic polyamines such as N-aminoethylpiperazine, 3,9-bis (3-aminopropyl) 2,4,8,10-tetraoxaspiro (5,5) undecane.

As the unsaturated carboxylic acid ester compound in the present invention, an acrylic acid or methacrylic acid ester compound represented by the following formula (II) is preferably used.

Embedded image R ¹ —CH ＝ CR ² —COOR ³ (II) (R ¹ is H, CH ₃ or C ₂ H ₅ , R ² is H or C
H ₃ and R ³ are a hydrocarbon group having 1 to 20 carbon atoms)

The acrylic acid or methacrylic acid ester compounds represented by the formula (II) used in the present invention include methyl acrylate, ethyl acrylate and acrylic acid.
n-butyl, i-butyl acrylate, t-butyl acrylate,
C1-C20 such as 2-ethylhexyl acrylate, lauryl acrylate, cetyl acrylate, stearyl acrylate, cyclohexyl acrylate, benzyl acrylate, isobornyl acrylate, glycidyl acrylate, tetrahydrofurfuryl acrylate, allyl acrylate, etc. Acrylic acid ester having a hydrocarbon group of; or methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, i-butyl methacrylate, t-butyl methacrylate,
2-ethylhexyl methacrylate, lauryl methacrylate, dodecyl pentadecyl methacrylate, tridecyl methacrylate, stearyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, isobornyl methacrylate, glycidyl methacrylate, tetrahydrofurfuryl methacrylate, allyl methacrylate, etc. And a methacrylate having a hydrocarbon group having 1 to 20 carbon atoms. Of these, acrylic acid is particularly preferred.
i-butyl, t-butyl acrylate, i-butyl methacrylate, and t-butyl methacrylate. The above-mentioned ester compounds of acrylic acid or methacrylic acid can be used in a mixture of two or more.

The reaction ratio of the polyamino compound and the unsaturated carboxylic acid ester compound is not particularly limited as long as gelation can be avoided and the obtained compound contains an amino group having active hydrogen. When the amount of the unsaturated carboxylic acid ester compound used is small, the pot life extension effect of the epoxy resin composition becomes small. Therefore, the preferable ratio is 0.1 mol or more of unsaturated carboxylic acid to 1 mol of polyamino compound.

The conditions for the Michael addition reaction between the polyamino compound and the unsaturated carboxylic acid ester compound are as follows: the reaction temperature is selected from the range of room temperature to 150 ° C. depending on the kind of the polyamino compound and the kind of the unsaturated carboxylic acid ester compound. Is selected in the range of 5 to 50 hours.

In the present invention, the compound obtained by the Michael addition reaction between the polyamino compound and the unsaturated carboxylic acid ester compound may be used alone as a polyamino epoxy resin curing agent or may be mixed with the polyamino epoxy resin curing agent. Good to use. The mixing amount in this case is not particularly limited.

The compound of the present invention obtained by the Michael addition reaction between the polyamino compound and the unsaturated carboxylic acid ester compound can be further modified and used as an amine raw material for a polyamino epoxy resin curing agent. In this case, it is preferable to use a compound obtained by a Michael addition reaction at a reaction ratio of 0.1 mol or more and 1 mol or less with respect to 1 mol of the polyamino compound, and the modification is used for a general polyamino-based curing agent. The method is not particularly limited. The reaction ratio in the denaturation is not particularly limited as long as gelation can be avoided and the obtained compound contains an amino group having active hydrogen.

Further, the compound of the present invention obtained by the Michael addition reaction between the polyamino compound and the unsaturated carboxylic acid ester compound is a modified product of the polyamino compound used in a usual epoxy resin curing agent, for example, a polyamino compound and a phenol compound and an aldehyde. Modified product of polyamino compound such as modified product by Mannich reaction with compound, modified product of reaction of polyamino compound and epoxy compound, modified product of reaction of polyamino compound and compound having carboxyl group, and unsaturated carboxylic acid ester compound May be used.
The reaction ratio between the polyamino compound and the unsaturated carboxylic acid ester compound is not particularly limited as long as gelation can be avoided and the obtained compound contains an amino group having active hydrogen. When the amount of the carboxylic acid ester compound used is small, the pot life extension effect of the epoxy resin composition becomes small, so the preferable reaction ratio is 0.1 mol or more of the unsaturated carboxylic acid ester compound to 1 mol of the modified product of the polyamino compound. is there.

The unsaturated carboxylic acid ester used for obtaining the compound by the Michael addition reaction of the present invention is not specified as a specific chemical substance or deleterious substance, and the compound of the present invention by the Michael addition reaction is not a deleterious substance. It is a substance not specified in. Therefore, compared with the cyanoethylated polyamino compound obtained by the Michael addition reaction of acrylonitrile and polyamino compound with acrylonitrile, these substances are less harmful, and the pot life of the epoxy resin composition can be extended more safely according to the present invention. Can be. The pot life extending method of the present invention is applied to an epoxy resin composition containing an epoxy resin and a polyamine-based curing agent as main components, and a compound obtained by a Michael addition reaction between a polyamino compound and an unsaturated carboxylic acid ester compound is: It slows down the reaction with a isocyanate as a chain extender of a polyurethane resin, and can be effectively used for improving workability in the field of paints and the like.

[0019]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. Evaluation of pot life and curing speed
According to the method described below. (1) Pot life 50 g of the epoxy resin composition was placed in a 100 ml polypropylene cup, left at 23 ° C. and a relative humidity of 50%, and the time required to reach the maximum heat generation temperature was measured. (2) Curing speed The curing speed was evaluated using an RCI curing speed tester. The epoxy resin composition was applied to a glass plate (25 × 350 × 2 mm) using a 76 μm applicator, and the time until each dry state was measured at 23 ° C. and 50% relative humidity.

Production Example 1 408.6 g (3.0 mol) of methaxylylenediamine and i-methacrylic acid were placed in a 1-liter reaction vessel equipped with a stirrer, a thermometer, a nitrogen inlet tube, and a condenser.
213.3 g (1.5 mol) of butyl was charged, and a Michael addition reaction was performed at 120 ° C. for 36 hours with stirring under a nitrogen stream to obtain 575.9 g of a polyamino compound A. The viscosity was 16 cp / 25 ° C. and the active hydrogen equivalent was 59.

Preparation Example 2 In a reaction vessel similar to that of Preparation Example 1, 408.6 g (3.0 mol) of methaxylylenediamine and t-butyl methacrylate 2 were added.
13.3 g (1.5 mol) was charged, and a Michael addition reaction was performed at 120 ° C. for 34 hours with stirring under a nitrogen stream.
569.2 g of a polyamino compound B was obtained. The viscosity is 15c
p / 25 ° C., and the active hydrogen equivalent was 59.

Production Example 3 408.6 g (3.0 mol) of meta-xylylenediamine was charged into a 1-liter reaction vessel equipped with a stirrer, a thermometer, a nitrogen inlet tube, a dropping funnel, and a condenser. Under stirring, 159.2 g (3.0 mol) of acrylonitrile was added dropwise at 80 ° C. over 2 hours. After completion of the addition, the temperature was raised to 100 ° C., and the mixture was reacted for 2 hours, and 560.2 g of cyanoethylated metaxylylenediamine. I got The viscosity was 44 cp / 25 ° C., and the active hydrogen equivalent was 63.

Production Example 4 In a reaction vessel similar to that used in Production Example 3, 408.6 g (3.0 mol) of metaxylylenediamine and 282.3 g (3.0 mol) of phenol were charged and placed under a nitrogen stream. At 80 ° C. with stirring, 3% containing 8% methanol.
162.2 g (2.0 mol) of a 7% aqueous solution was added dropwise over 1.5 hours, and after completion of the dropwise addition, the temperature was raised to 100 ° C. and the reaction was carried out for 1.5 hours. Further, while distilling off water, 150
C., and the reaction was carried out at the same temperature for 1 hour to obtain 714.7 g of a Mannich modified curing agent. The viscosity is 2000 cp /
The temperature was 25 ° C., and the active hydrogen equivalent was 72.

Example 1 31 g of the polyamine compound A obtained in Production Example 1 was mixed with a bisphenol A type liquid epoxy resin (epoxy equivalent: 19).
0, manufactured by Yuka Shell Epoxy Co., Ltd., trade name: Epicoat 828), and mixed to prepare an epoxy resin composition. The pot life and curing speed of the obtained epoxy resin composition were evaluated. Table 1 shows the evaluation results.

Example 2 31 g of the polyamine compound B obtained in Production Example 2 was mixed with a bisphenol A type liquid epoxy resin (epoxy equivalent: 19).
0, manufactured by Yuka Shell Epoxy Co., Ltd., trade name: Epicoat 828) and mixed to prepare an epoxy resin composition. The pot life and curing speed of the obtained epoxy resin composition were evaluated. The evaluation results are shown in Table 1.

Comparative Example 1 33 g of the cyanoethylated m-xylylenediamine obtained in Production Example 3 was mixed with a bisphenol A type liquid epoxy resin (epoxy equivalent 190, manufactured by Yuka Shell Epoxy Co., Ltd.)
Product name: Epikote 828) Add to 100g and mix,
An epoxy resin composition was prepared. The pot life and curing speed of the obtained epoxy resin composition were evaluated. Table 1 shows the evaluation results.

[0027]

Table 1 Example 1 Example 2 Comparative Example 1 Epoxy resin composition (g) Epicoat 828 100 100 100 Polyamino compound A 31 Polyamino compound B 31 Cyanoethylated meta-xylylenediamine 33 Pot life Maximum exothermic temperature (° C) 84 85 31 Arrival time (Min) 260 310 280 Curing speed (Hr: Min) Dry to touch 4:45 3:45 6:30 Semi-dry 6:15 5:15 11:00 Complete dry 20:00 18:00 24 hours or more

As shown in Table 1, when the polyamino compound A or the polyamino compound B obtained by the Michael addition reaction of the polyamino compound of the present invention with the unsaturated carboxylic acid ester compound was used for the epoxy resin composition, cyanoethylated metaxylyl It can be seen that the pot life is equivalent, but the curing speed is faster than when using a range amine.

Example 3 60 parts by weight of the Mannich modified curing agent obtained in Production Example 4 and 40 parts by weight of the polyamino compound obtained in Production Example 1 were mixed, and had a viscosity of 190 cp / 25 ° C. and an active hydrogen equivalent of 67.
Of curing agent A was obtained. 35 g of the curing agent A was added to a bisphenol A type liquid epoxy resin (epoxy equivalent: 190, manufactured by Yuka Shell Epoxy Co., Ltd., trade name: Epicoat 828) 10
The resulting mixture was added to 0 g and mixed to prepare an epoxy resin composition.
The pot life, curing speed and curing speed of the obtained epoxy resin composition were evaluated. Table 2 shows the evaluation results.

Example 4 60 parts by weight of the Mannich modified curing agent obtained in Production Example 4 and 40 parts by weight of the amine compound obtained in Production Example 2 were mixed, and had a viscosity of 170 cp / 25 ° C. and an active hydrogen equivalent of 67. Of curing agent B was obtained. 35 g of curing agent B was added to bisphenol A
Type liquid epoxy resin (epoxy equivalent 190, manufactured by Yuka Shell Epoxy Co., Ltd., trade name: Epicoat 828) 100
g and mixed to prepare an epoxy resin composition. The pot life and curing speed of the obtained epoxy resin composition were evaluated. Table 2 shows the evaluation results.

Comparative Example 2 38 g of the Mannich modified curing agent obtained in Production Example 4 was mixed with a bisphenol A type liquid epoxy resin (epoxy equivalent: 19).
0, manufactured by Yuka Shell Epoxy Co., Ltd., trade name: Epicoat 828) and mixed to prepare an epoxy resin composition. The pot life and curing speed of the obtained epoxy resin composition were evaluated. Table 2 shows the evaluation results.

Comparative Example 3 60 parts by weight of the Mannich curing agent obtained in Production Example 4 and 40 parts by weight of the cyanoethylated metaxylylenediamine obtained in Production Example 3 were mixed, and the viscosity was 270 cp / 25 ° C. and the active hydrogen equivalent was 68. Of curing agent C was obtained. 36 g of the obtained curing agent C
Was added to 100 g of a bisphenol A liquid epoxy resin (epoxy equivalent: 190, manufactured by Yuka Shell Epoxy Co., Ltd., trade name: Epicoat 828) and mixed to prepare an epoxy resin composition. The pot life and curing speed of the obtained epoxy resin composition were evaluated. Table 2 shows the evaluation results.

[0033]

Table 3 Example 3 Example 4 Comparative Example 2 Comparative Example 3 Epoxy resin composition (g) Epicoat 828 100 100 100 100 Curing agent A 35 Curing agent B 35 Mannich modified curing agent 38 Curing agent C 36 Pot life Maximum heat generation temperature (° C) 175 180 185 170 Arrival time (Min) 30 32 15 31 Curing rate (Hr: Min) Dry to touch 1:45 1:30 1:00 2:00 2:00 Semi-dry 2:30 2:15 2:00 3 : 30 Complete drying 7:30 7:15 7:00 8:30

As can be seen from Table 2, when cyanoethylated metaxylylenediamine was used together with the Mannich-modified curing agent (Comparative Example 3), the pot life was prolonged, but the curing speed of the epoxy resin composition was also decreased. On the other hand, when a compound obtained by a Michael addition reaction of the polyamino compound of the present invention with an unsaturated carboxylic acid ester compound is used, the pot life is almost the same as when cyanoethylated metaxylylenediamine is used. It can be seen that the effect of reducing the curing speed is small.

[0035]

As is clear from the above Examples and Comparative Examples, by using a compound obtained by a Michael addition reaction of a polyamino compound and an unsaturated carboxylic acid ester compound in an epoxy resin composition according to the present invention,
The pot life of the epoxy resin composition at room temperature curing is extended. In the method of the present invention, the effect of lowering the curing rate of the epoxy resin composition is small, and the compound obtained by the Michael addition reaction according to the present invention is a low-viscosity liquid at ordinary temperature and has low harmfulness. Therefore, the workability of the epoxy curing agent is improved by the method of the present invention, and the epoxy resin composition can be used efficiently and safely.

Claims (3)

[Claims] 1. A method for extending the pot life of an epoxy resin composition, comprising using a compound obtained by a Michael addition reaction between a polyamino compound and an unsaturated carboxylic acid ester compound. 2. The method for extending the pot life of an epoxy resin composition according to claim 1, wherein the polyamino compound is a diamine represented by the formula (I). Embedded image H ₂ N—H ₂ CA—CH ₂ —NH ₂ (I) (A represents a phenylene group or a cyclohexylene group) 3. An unsaturated carboxylic acid ester compound comprising (II)
The method for extending the pot life of an epoxy resin composition according to claim 1, which is an ester compound of acrylic acid or methacrylic acid represented by the formula. Embedded image R ¹ —CH ＝ CR ² —COOR ³ (II) (R ¹ is H, CH ₃ or C ₂ H ₅ , R ² is H or C
H ₃ and R ³ are a hydrocarbon group having 1 to 20 carbon atoms)