JPH1135661A - Epoxy resin curing agent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject agent, which is hardly influenced by carbon dioxide gas, having a long pot life, by reacting a specific maleic acid derivative and the like with a specific polyoxyalkylamine at a specific ratio, followed by the addition of a predetermined amount of a specific polyamine compound to allow reaction. SOLUTION: This agent is obtained by reacting (A) a maleic acid or fumaric acid derivative selected from maleic acid, fumaric acid, acid anhydrides of these, and a dialkyl ester having 1-4C alkyl groups with (B) a polyoxyalkyleneamine having skeletal structure shown by formula I [R is formula II, CH3 O; R' is H or CH3 ; (n) is 1-20] at an (A:B) ratio of (1:0.5)-(1:2.5), followed by the addition of (C) a polyamine compound having two or more aminomethyl groups linked to an aromatic or aliphatic ring (e.g. m- xylenediamine) at an (A:B+C) ratio of (1:3.0)-(1:3.5) to complete the reaction. The epoxy resin curing agent can be diluted down to 30 wt.% or lower with water.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a curing agent for epoxy resins, and more particularly, to a curing agent for epoxy resins using a polyamine compound.

[0002]

2. Description of the Related Art Epoxy resin compositions are used in a wide range of industrial fields such as paints for corrosion protection and cosmetics, civil engineering, and construction adhesives. Conventionally, aliphatic and alicyclic polyamine compounds are cured at room temperature. It is widely used as an epoxy resin curing agent or its raw material. Representative polyamine compounds, diethylene triamine, polyalkylene polyamines such as triethylene tetramine, polyoxyethylene polyamine, polyoxyalkylene amines such as polyoxypropylene polyamine, meta-xylylenediamine,
Examples thereof include aliphatic polyamines having an aromatic ring such as paraxylylenediamine, and alicyclic polyamines such as 1,2-diaminocyclohexane and isolophoronediamine.

[0003] These polyamine compounds each have a characteristic characteristic of amino group reactivity, that is, active hydrogen, and these amine compounds may be used as they are or after modification suitable for each polyamine compound. Used as an epoxy resin curing agent. In addition, among aliphatic and alicyclic polyamine compounds, polyamine compounds composed of a ring skeleton such as a benzene ring or a cyclohexane ring and an aminomethyl group, for example, metaxylylenediamine, bisaminomethylcyclohexane, etc. It has excellent reactivity and is used especially as a raw material of a curing agent for low-temperature curing.

[0004] These polyamine compounds have drawbacks such as being susceptible to interaction with water or carbon dioxide gas in the air, and having too high a reactivity with an epoxy resin, resulting in a short pot life at room temperature. Therefore, when these polyamine compounds are used as a curing agent, various modifications such as Mannich modification, polyamide modification, epoxy adduct modification, and Michael addition modification are usually performed, and the curing agent obtained by such modification has a high viscosity. Tends to be. When the rate of modification is reduced to reduce the viscosity of the curing agent, a relatively large amount of unreacted amine remains in the curing agent, and this so-called free amine causes the aforementioned disadvantages, such as the interaction of water and carbon dioxide gas in the air. As a result, defects such as stickiness and whitening of the surface of the cured product appear. JP-B-62-53530 discloses that 0.1 to 10% of a monoalkylamine having 6 to 18 carbon atoms is used.
Add to suppress the interaction of water and carbon dioxide in the air,
Although a method for improving the surface properties of a cured product has been disclosed, such monoamines have poor compatibility with a curing agent and have a drawback that turbidity occurs when stored for a long period of time.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to improve the above-mentioned drawbacks in a curing agent for an epoxy resin using a polyamine compound, to be less susceptible to carbon dioxide gas, to have a longer pot life, and to be sufficient at room temperature. It is an object of the present invention to provide a room temperature curing type epoxy resin curing agent having a high reactivity with an epoxy resin.

[0006]

The present inventors have conducted intensive studies on epoxy resins having the above-mentioned problems, and as a result, have found that maleic acid or fumaric acid derivatives selected from acid anhydrides or dialkyl esters having 1 to 4 carbon atoms. Is partially reacted with a polyoxyalkyleneamine having a specific structure, and an aliphatic amine having at least two aminomethyl groups bonded to an aromatic ring skeleton or an aliphatic ring skeleton is added to complete the reaction. The obtained curing agent is hardly affected by carbon dioxide gas and water, has a long pot life, and has sufficient reactivity with the epoxy resin at room temperature, and particularly the properties of the cured product obtained by reacting with the epoxy resin. The inventors have found that hardness, adhesion, impact resistance and the like are excellent, and have completed the present invention.

That is, the present invention provides a maleic acid or fumaric acid derivative (A) selected from maleic acid, fumaric acid, said acid anhydride and said dialkyl ester having an alkyl group having 1 to 4 carbon atoms, and (I) )) A polyoxyalkyleneamine (B) having a skeleton represented by the formula:
(B) is reacted at a ratio of 0.5 to 2.5 mol per mol, and at least 2 is reacted with the aromatic ring skeleton or the aliphatic ring skeleton.
The polyamine compound (C) to which one or more aminomethyl groups are bonded, (B) + (C) is (3) per mole of (A).
An epoxy resin curing agent obtained by adding 0 to 3.5 mol at a ratio and then completing the reaction.

[0008]

Embedded image R ′ is H or CH ₃ , and n is an integer of 1 ≦ n ≦ 20.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The maleic acid or fumaric acid derivative (A) used in the present invention is an acid anhydride or a dialkyl ester having 1 to 4 carbon atoms, such as maleic anhydride, dimethyl maleate or maleic acid. Examples thereof include diethyl, di-n-butyl maleate, dimethyl fumarate, diethyl fumarate, and di-n-butyl fumarate. Maleic anhydride, dimethyl maleate, and dimethyl fumarate are preferably used.

Derivatives of maleic acid or fumaric acid (A)
The polyoxyalkyleneamines (B) to be reacted with a propylene oxide polymer having a terminal amino group bonded to a propylene oxide residue or propylene oxide and ethylene oxide as shown in the following formula (II): And n is 1 ≦ n ≦ 20, preferably 1 ≦ n ≦ 10.

Embedded image

Specific examples of the polyoxyalkyleneamines (B) include JEFFAMINED-230 and D-40.
0, ED-600, ED-900, M-600, M-1
000 (all are trade names manufactured by HUNTSMAN). If the average degree of polymerization is too large, the performance of the epoxy resin cured with the obtained curing agent, particularly the hardness of the cured product, will decrease. Preferred is JEFFAMINE
D-230, D-400, ED-600 and the like.

The polyamine compound (C) having at least two aminomethyl groups bonded to an aromatic ring skeleton or an aliphatic ring skeleton used in the present invention includes metaxylylenediamine, paraxylylenediamine, 2,6-bis Aliphatic amines having an aromatic ring such as aminomethylnaphthalene,
Examples include alicyclic amines having an aliphatic ring skeleton such as 1,3-bisaminomethylcyclohexane and bisaminomethylnorbornane, and meta-xylylenediamine conventionally used as a solvent-type or non-solvent-type epoxy resin curing agent. , 1,3-bisaminomethylcyclohexane and bisaminomethylnorbornane are preferably used.

Derivatives of maleic acid or fumaric acid (A)
And a polyoxyalkyleneamine (B) and a polyamine compound (C) in which at least two or more aminomethyl groups are bonded to an aromatic ring skeleton or an aliphatic ring skeleton have a reaction ratio of (A) per 1 mol. (B) is 0.5 to 2.5
Mol, (B) + (C) is preferably from 3.0 to 3.5 mol. When the reaction ratio of (B) is 0.5 mol or less, the effect of extending the pot life and the effect of preventing whitening and stickiness of the coating film become extremely low, and when the reaction ratio is 2.5 mol or more, the epoxy resin cured with the obtained curing agent. , Especially the hardness of the cured product decreases. When (B) + (C) is 3.0 mol or less, gelation occurs during the synthesis, and when it is 3.5 or more, too much free amine remains, so that the pot life is extended and the coating film is prevented from whitening and stickiness. Becomes extremely low. A particularly preferable reaction ratio is that (B) is 1.0 to 2.0 with respect to 1 mol of (A).
Mol, (B) + (C) is 3.0 to 3.5 mol.

In the present invention, the maleic acid or fumaric acid derivative (A) and the polyoxyalkyleneamines (B)
When (A) is an acid anhydride, the reaction conditions are as follows:
The acid anhydride (A) is added to (B) in a temperature range of -130 ° C.
Add gradually over 5 to 3 hours, and after addition is complete,
It is preferred to react after 0 to 3 hours at 0 ° C. In this reaction, the reaction solution may have a high viscosity due to the addition of an acid anhydride. In this case, an aromatic hydrocarbon solvent such as toluene and xylene or an ether solvent such as tetrahydrofuran may be used in combination. The method for adding the acid anhydride may be divided addition as a solid, or may be dropped by heating and melting.
It may be dissolved in an aromatic hydrocarbon solvent such as toluene or xylene and dropped.

When the dialkyl ester of maleic acid or fumaric acid (A) is reacted with a polyoxyalkyleneamine (B), (A) is added to (B) in a temperature range of 50 to 130 ° C. Add gradually over 3 hours,
After completion of the addition, the reaction may be carried out for 0.5 to 3 hours in a temperature range of 80 to 130 ° C, or (A) and (B) may be charged at a time, and 0.5 to 6 for a temperature range of 50 to 130 ° C. You may make it react for time. In this reaction, even if a dialkyl maleate is used, a dialkyl fumarate is generated by the isomerization reaction and may sublimate and adhere to the upper portion of the reaction vessel.
The reaction may be carried out under reflux using the aliphatic alcohol of No. 4 together. The method of adding the dialkyl ester (A) may be added dropwise as it is or in divided portions, or may be added dropwise by dissolving it in an aliphatic alcohol having 1 to 4 carbon atoms such as methanol.

In the present invention, the maleic acid or fumaric acid derivative (A) and the polyoxyalkyleneamines (B)
The reaction of the product of the reaction with the polyamine compound (C) having at least two aminomethyl groups bonded to the aromatic ring skeleton or the aliphatic ring skeleton is performed by reacting a maleic acid or fumaric acid derivative (A) with an anhydride. Is mainly an amidation reaction, and if a dialkyl ester is used, it is an ester amide exchange reaction.At a temperature range of 140 to 240 ° C., preferably 140 to 200 ° C. while distilling off water or alcohol, The reaction can be completed by reacting for 1 to 6 hours. In order to promote the distillation of water or alcohol, the reaction may be carried out under reduced pressure, or may be carried out under reduced pressure after completion of the reaction to distill off.

When an epoxy resin composition is produced using the epoxy resin curing agent of the present invention, the epoxy resin may be a bisphenol A type epoxy resin obtained by reacting bisphenol A with epichlorohydrin, or a reaction between bisphenol F and epichlorohydrin. Bisphenol AD epoxy resin obtained by the reaction of bisphenol AD with epichlorohydrin, and so-called phenol novolak epoxy resin obtained by the reaction of phenol / formaldehyde condensate with epichlorohydrin.

These epoxy resins may be used after being diluted with a solvent, or may be used in the form of an emulsion dispersed in water using an emulsifier. Is also good. When preparing an epoxy resin composition using an emulsion type epoxy resin, the curing agent of the present invention can be used after being diluted with water to a concentration of 30 to 100% by weight, and using a liquid type epoxy resin. When producing an epoxy resin composition, the curing agent of the present invention may be used after being diluted with a known non-reactive diluent such as benzyl alcohol to a concentration of 50 to 100% by weight. When an epoxy resin composition is produced using the epoxy resin curing agent of the present invention, known pigments such as calcium carbonate and talc, fillers, and further, a leveling agent, an antifoaming agent, and the like can be appropriately used.

[0019]

Next, the contents of the present invention will be described in detail with reference to examples. However, the present invention is not limited by the following examples.

Example 1 A 500 ml internal reaction vessel equipped with a stirrer, a thermometer, a nitrogen inlet tube, a dropping funnel and a condenser was charged with JEFFA as polyoxypropylenediamine.
230 g (1 mol) of MINE D-230 (manufactured by HUNTSUMAN Co., Ltd., average molecular weight 230) was charged, and 94 g (0.5 g) of maleic anhydride (manufactured by Mitsubishi Gas Chemical Co., Ltd.) at 90 to 100 ° C. while stirring under a nitrogen stream. Mol) was added in portions over 1 hour. After the addition was completed, the reaction temperature was raised to 115 ° C., and the reaction was performed for 2 hours. 136 g (1.0 mol) of meta-xylylenediamine (manufactured by Mitsubishi Gas Chemical Co., Ltd.) was added thereto, and the mixture was reacted at 115 ° C. for 1 hour, and then heated to 180 ° C. while distilling off generated water. 1 hour, 2 more
The temperature was raised to 00 ° C. and the reaction was carried out for 2 hours, and the product was taken out by cooling to 60 ° C. (the total dehydration amount was 8 g (theoretical value 9 g)).
The obtained curing agent had a viscosity of 1000 (ps / 25 ° C.), an active hydrogen equivalent of 96 (g / equivalent), and a total amine value of 312 (mgK).
OH / g, theoretical 331). Further, water was gradually added to 10 g of the curing agent while stirring, and a critical concentration (hereinafter referred to as a water dilutable limit concentration) at which phase separation was measured was 14% by weight.

Example 2 In the same reaction vessel as used in Example 1, JEFFAMINE D-4 was used as polyoxypropylenediamine.
00 (manufactured by HUNTSSUMAN, average molecular weight 400) 2
Then, 94 g (0.5 mol) of maleic anhydride was added in portions over 1 hour at 90 to 100 ° C. while stirring under nitrogen flow. After the addition was completed, the reaction temperature was raised to 115 ° C., and the reaction was carried out for 1 hour. 163 g (1.2 mol) of m-xylylenediamine was added thereto, and the reaction was carried out at 115 ° C for 1 hour. Then, the temperature was raised to 180 ° C for 1 hour while distilling off generated water, and further heated to 200 ° C. The mixture was allowed to react for 2 hours, cooled to 60 ° C., and the product was taken out (total dehydration amount: 7 g (theoretical value: 9 g)). The obtained curing agent had a viscosity of 265 (ps / 25 ° C.) and an active hydrogen equivalent of 95.
(G / equivalent), the total amine value was 313 (mg KOH / g, theoretical value 331), and the limiting concentration in water dilutability was 29% by weight.

Example 3 In the same reaction vessel as used in Example 1, JEFFAMINE ED- was used as polyoxypropylenediamine.
600 (manufactured by HUNTSSUMAN, average molecular weight 600)
300 g (0.5 mol) were charged and 94 g (0.5 mol) of maleic anhydride was added at 90-100 ° C. while stirring under a nitrogen stream.
Mol) was added in portions over 1 hour. After the addition was completed, the reaction temperature was raised to 115 ° C., and the reaction was carried out for 1 hour. After adding 136 g (1.0 mol) of meta-xylylenediamine thereto and reacting at 115 ° C. for 1 hour, the temperature was raised to 180 ° C. for 1 hour while distilling off generated water, and further raised to 200 ° C. The mixture was allowed to react for 2 hours, cooled to 60 ° C., and the product was taken out (total dehydration amount: 7 g (theoretical value: 9 g)). The obtained curing agent had a viscosity of 175 (ps / 25 ° C.) and an active hydrogen equivalent of 13
6 (g / equivalent), total amine value 223 (mg KOH / g,
Theoretical value 235), and the water dilutability was completely water-soluble.

Comparative Example 1 In a reaction vessel similar to that used in Example 1, JEFFAMINE EDR was used as polyoxypropylenediamine.
-148 (HUNTSSUMAN, average molecular weight 14
8) 74 g (0.5 mol) was charged and dimethyl maleate (reagent:
72 g (0.5 mol) of Wako Pure Chemical Industries, Ltd. was added dropwise over 1 hour, and after completion of the addition, the reaction temperature was raised to 115 ° C.
A time reaction was performed. There meta-xylylenediamine 13
After adding 6 g (1.0 mol) and reacting at 115 ° C. for 1 hour, the temperature was raised to 160 ° C. for 1 hour while methanol was distilled off, and further reacted at 180 ° C. for 2 hours.
The product was taken out by cooling to 60 ° C. (the total amount of distilled methanol was 26 g (theoretical value: 32 g)). The obtained curing agent had a viscosity of 4,100 (ps / 25 ° C.) and an active hydrogen equivalent of 71 (g).
/ Equivalent), total amine value 443 (mg KOH / g, theoretical value 448), and water dilutable limit concentration was 23% by weight.

Comparative Example 2 In a reaction vessel similar to that used in Example 1, 340 g (2.5 mol) of metaxylylenediamine was charged and stirred at 90 to 100 ° C. under a stream of nitrogen at 90 to 100 ° C. for dimethyl maleate 105. 8.8 g (0.735 mol) was added dropwise over 1 hour, and after completion of the addition, the reaction temperature was raised to 115 ° C., and the reaction was carried out for 2 hours. Thereafter, 16
The temperature was raised to 0 ° C. and reacted for 1 hour, and further raised to 180 ° C. for 2 hours, cooled to 60 ° C., and the product was taken out (total distillate methanol amount: 42 g (theoretical value: 47 g)). The obtained curing agent had a viscosity of 4,400 (ps / 25 ° C.), an active hydrogen equivalent of 63 (g / equivalent), and a total amine value of 487 (mg KOH).
/ G, theoretical value 496), water dilutable limit concentration 48% by weight
Met.

Application Example 1 14.6 g of benzyl alcohol (reagent: Wako Pure Chemical Industries, Ltd.) as a diluent was added to 24.2 g of the curing agent obtained in Example 1.
(30 parts by weight with respect to 70 parts by weight of curing agent) to make a uniform solution, and as an epoxy resin, Epicoat 828 (epoxy equivalent 190: manufactured by Yuka Shell Epoxy Co., Ltd.)
5 g (1 mol of epoxy group per 1 mol of active hydrogen of the curing agent) was added and stirred well to prepare an epoxy resin composition. This composition was polished with a # 240 sandpaper and degreased in xylene to form a cold-rolled steel sheet (size: 70 × 150 ×
(0.8 mm) using a 200 μm doctor blade and cured at 23 ° C. and 50% RH for 7 days to form a coating film. Table 1 shows the compounding ratios of the compositions used, the pot life, and the evaluation results of the coating films.

Application Example 2 To 23.8 g of the curing agent obtained in Example 2, 10.2 g of benzyl alcohol (30 parts by weight with respect to 70 parts by weight of the curing agent) was added as a diluent to obtain a uniform solution. Add 47.5 g of Epicoat 828 as a resin (1 mol of epoxy group to 1 mol of active hydrogen of the curing agent) and stir well to adjust the epoxy resin composition.
A coating was formed. Table 1 shows the compounding ratios of the compositions used, the pot life, and the evaluation results of the coating films.

Application Example 3 To 34.0 g of the curing agent obtained in Example 3, 14.6 g of benzyl alcohol (30 parts by weight with respect to 70 parts by weight of the curing agent) was added as a diluent to obtain a homogeneous solution, Add 47.5 g of Epicoat 828 as a resin (1 mol of epoxy group to 1 mol of active hydrogen of the curing agent) and stir well to adjust the epoxy resin composition.
A coating was formed. Table 1 shows the compounding ratios of the compositions used, the pot life, and the evaluation results of the coating films.

Application Example 4 6.85 g of the curing agent obtained in Example 2 was added to 6.14 g of distilled water.
g of solid epoxy resin emulsion Araldite PZ-39 as an epoxy resin.
32 (88% solid content: 55%, epoxy equivalent: 535 (solid content conversion: Ciba-Geigy)) (1 mol of epoxy group per 1 mol of active hydrogen of the curing agent) was added, and the mixture was stirred well and mixed with an aqueous epoxy resin composition. Was adjusted, and a coating film was prepared in the same manner as in Application Example 1. The proportion of the composition used,
Table 1 summarizes the evaluation results of the coating films. Note that no heat generation was observed in this epoxy resin composition.

Application Example 5 Curing agent obtained in Comparative Example 1 17.
6. Benzyl alcohol as diluent in 9 g 7 g (30 parts by weight with respect to 70 parts by weight of the curing agent) was added to make a uniform solution. As an epoxy resin, 47.5 g of Epicoat 828 (1 mol of epoxy group per 1 mol of active hydrogen of the curing agent) was added and stirred well. Then, the epoxy resin composition was adjusted, and a coating film was formed in the same manner as in Application Example 1. Table 1 shows the compounding ratios of the compositions used, the pot life, and the evaluation results of the coating films.

Application Example 6 To 15.8 g of the curing agent obtained in Comparative Example 2, 6.8 g of benzyl alcohol (30 parts by weight with respect to 70 parts by weight of the curing agent) was added as a diluent to form a uniform solution. 47.5 g of Epicoat 828 as a resin (active hydrogen 1
The epoxy resin composition was adjusted by adding well and stirring well, and a coating film was prepared in the same manner as in Application Example 1. Table 1 shows the compounding ratios of the compositions used, the pot life, and the evaluation results of the coating films.

[0031]

[Table 1] Application example 1 2 3 4 5 6 Mixing ratio (parts by weight) Epicoat 828 100 100 100-100 100 Araldite PZ-3901---100--Curing agent of Example 1 50.5------Example Curing agent of 2-50.0-8.7--Curing agent of Example 3--71.6---Curing agent of Comparative example 1----37.4-Curing agent of Comparative example 2-----33.2 Benzyl alcohol 21.6 21.4 30.7 − 16.0 14.2 Water − − − 18.7 − − Pot life Maximum exothermic temperature (℃) 32 46 31 − 107 133 Arrival time (min) 110 97 88 − 41 33 Evaluation result of coating film Coating appearance ◎ ○ ○ ◎ × ○ Pencil hardness 1 day after application H2H HF 2H 7 days after application 3H 2H H 2H 3H 3H Adhesion to steel plate Erichsen (mm) 9 <8.9 9 <9 <7.6 8.7 Cross-cut test (/ 100) 98 100 100 100 20 0 Impact resistance Dubon impact Table 50 50 50 50 10 10 (1/2 ", 1kg × cm) Back 50 50 50 50 10F 10F

In this application example, the evaluation of the cured film was carried out.
The display was based on the following method. (1) Appearance of coating film (after curing for 7 days) The appearance of the cured coating film was evaluated by the following symbols. ◎: very good ○: good △: slightly poor ×:
Poor (2) Pot life 50 g of the epoxy resin composition was weighed, and the maximum exothermic temperature and the time to reach the temperature were measured in an environment of 23 ° C. (3) Pencil hardness, adhesion to steel plate, impact resistance (after curing for 7 days) The pencil hardness, Erichsen, cross cut test and Dubon impact test were based on JIS K5400.

[0033]

As is evident from the above examples and application examples, the epoxy resin curing agent of the present invention provides a room temperature curable epoxy resin having good surface properties, a long pot life and good physical properties of various cured products. A composition can be obtained.

Claims (4)

[Claims] 1. A maleic acid or fumaric acid derivative (A) selected from maleic acid, fumaric acid, said acid anhydride and said dialkyl ester having an alkyl group having 1 to 4 carbon atoms, and a compound represented by the formula (I): An aromatic ring skeleton or an aliphatic ring skeleton is obtained by reacting a polyoxyalkyleneamine (B) having the skeleton structure shown in the formula (B) at a ratio of 0.5 to 2.5 mol per 1 mol of (A). A polyamine compound (C) having at least two aminomethyl groups bonded thereto,
(A) (B) + (C) is 3.0 to 3.5 with respect to 1 mol.
An epoxy resin curing agent, which is obtained by adding at a molar ratio and then completing the reaction. Embedded image R ′ is H or CH ₃ , and n is an integer of 1 ≦ n ≦ 20. 2. Polyoxyalkyleneamines (B)
The epoxy resin curing agent according to claim 1, wherein is a polyoxypropylenediamine having a skeleton represented by the formula (II). Embedded image Here, n is an integer of 1 ≦ n ≦ 10. 3. The epoxy resin curing agent according to claim 2, wherein the polyamine compound (C) in which at least two aminomethyl groups are bonded to an aromatic ring skeleton or an aliphatic ring skeleton is meta-xylylenediamine. 4. The water-dilutable epoxy resin curing agent according to claim 1, which is dilutable in water to at least 30% by weight.