JPH0699545B2 - Curing agent - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to an amine-based curing agent, and more particularly to a curing agent obtained by modifying a polyvalent amine with a bisphenol and an epoxy compound.

TECHNICAL BACKGROUND OF THE INVENTION AND PROBLEMS THEREOF Various amines and organic acid anhydrides are conventionally known as curing agents used in epoxy resins. However, the conventionally used amine-based or acid anhydride-based curing agents have a problem that the flexibility of the cured product thus cured is relatively low and easily fragile.

On the other hand, in order to solve such a problem, it has been conventionally known to use a phenolic hydroxyl group-containing compound synthesized from bisphenol and an epoxy compound as a curing agent, but it is cured using this curing agent. The cured product is
Although it shows some improvement in flexibility, there was a problem that the heat resistance of this cured product, particularly the hot water resistance, was still low.

Furthermore, in the conventionally known compound containing a phenolic hydroxyl group, novolac or polyhydric (trivalent or more) phenol is used as a raw material for synthesizing the compound, but novolac tends to make a cured product brittle, while Polyhydric phenol is also expensive and disadvantageous in terms of manufacturing cost.

OBJECT OF THE INVENTION The present invention is intended to solve the problems associated with the prior art as described above, and can provide a cured product having excellent flexibility and heat resistance. Moreover, it is an object of the present invention to provide a curing agent which is advantageous in terms of manufacturing cost.

SUMMARY OF THE INVENTION The curing agent according to the present invention is obtained by mixing bisphenols, an epoxy compound, and a polyamine to react with each other, and a branched amine adduct having a structure in which bisphenol having a hydroxyl group is added to the terminal. It is characterized by including.

Thus, the curing agent according to the present invention is obtained by mixing and reacting bisphenols, epoxy compounds and polyvalent amines, and a branched amine adduct having a structure in which bisphenol having a hydroxyl group is added to the terminal. Therefore, a cured product excellent in both flexibility and heat resistance can be obtained, and a relatively low-priced raw material is used, which is also advantageous in cost reduction.

Detailed Description of the Invention Hereinafter, the curing agent according to the present invention will be specifically described including Examples.

As the bisphenols as a raw material, conventionally known ones, for example, bisphenols such as bisphenol A and bisphenol F can be used, but bisphenol A is particularly preferably used in order to obtain a cured product having good physical properties.

As the epoxy compound, an epoxy compound having two epoxy groups can be used. Further, these epoxy compounds include glycidyl ethers that can be added to amines and long-chain olefin epoxides, but in order to impart good flexibility and heat resistance to a cured product, specifically, a bisphenol type epoxy resin is used. Is used.

As the polyvalent amine used as a raw material, an aliphatic polyvalent amine,
Aromatic polyvalent amines are used. Specifically, xylylenediamine, 1,3-bis (aminomethyl) cyclohexane (1,3-BAC), diaminodiphenylmethane (DDM), hydrogenated diaminodiphenylmethane (benzene nucleus is Hydrogenated), bis (3-methyl-4-aminocyclohexyl) methane, phenylenediamines and the like can be preferably used.

The curing agent according to the present invention can be obtained by reacting the above components. To react each of these components to produce the curing agent according to the present invention, for example, bisphenols, epoxy compounds, polyvalent amines are mixed in a solvent, and a catalyst such as triphenylphosphine or tetramethylammonium chloride is used. It may be heated to 100 to 150 ° C in the presence.

The amine adduct thus obtained has a structure in which a bisphenol and an epoxy compound are added in a branched state to each nitrogen atom of a polyvalent amine such as xylylenediamine, and bisphenol having a hydroxyl group is added to the terminal. Further, among those having a deduced structure represented by the following formula [I], those containing a molecule having a branched deduced structure of II are obtained.

As shown in the above structural formula, in the curing agent of the present invention, since the bisphenol having a hydroxyl group is added in a branched state at the terminal, one bisphenol terminal hydroxyl group and another bisphenol terminal hydroxyl group are added. Are separated from each other, and each hydroxyl group can effectively contribute to the curing reaction without causing steric hindrance. For this reason, the curing agent according to the present invention can exhibit good curing reactivity and has a relatively long carbon chain added. Therefore, a cured product cured with this curing agent is It has excellent flexibility. Moreover, it is presumed that the reason why it is also excellent in hot water resistance is the same.

The curing agent of the present invention is particularly useful as a curing agent for epoxy resins.

When curing the epoxy resin using the curing agent of the present invention,
The amount of curing agent added is usually an epoxy resin (epoxy equivalent
1045) It is preferably 20 to 28 parts per 100 parts.

Further, the curing conditions are usually 150 to 230 ° C. for a heating time of 5 to 30 minutes, although it varies depending on the use and the additive used in combination.
The pot life is 5 to 30 days (however, 3 months or more in the case of solid solution such as powder coating).

The curing agent of the present invention is usually used by blending it with an epoxy resin together with desired additives such as a curing accelerator, a filler, a flow regulator and a pigment.

Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited to these examples.

Comparative Example 1 193 parts of liquid epoxy resin (R-140P: EEW188), 307 parts of bisphenol A and 50 parts of xylene were weighed into a reactor (theoretical phenol equivalent: 300), heated to 120 ° C under a nitrogen atmosphere, Methylammonium chloride (TMAC) aqueous solution is generated with nitrogen content, and 50ppm is added to the amount of curing agent.
Heated to ° C. When the temperature reached 130 ° C, xylene and water were distilled off under reduced pressure, and then the reaction was carried out at 130 ° C for 6 hours in a nitrogen atmosphere.

After the completion of the reaction, 61 parts of 2-methylimidazole (10.9% by weight based on the amount of the generated curing agent) was added and mixed by stirring for 15 minutes to obtain a product.

The generated curing agent has a softening point of 81 ° C, 25 ° C clay (GH) I-J
That physical property was given.

Comparative Example 2 After terminating the reaction under the same synthetic conditions as in Comparative Example 1, 2-
36.5 parts of methyl imidazole (6.8% based on the amount of curing agent produced)
%) Was added and mixed by stirring for 15 minutes to obtain a product.

The generated curing agent is clay (GH) J at softening point 84 ℃ and 25 ℃.
That physical property was given.

Example 1 159.1 parts of liquid epoxy resin (R-140P: EEW188), 328.4 parts of bisphenol A and 50 parts of xylene were weighed out in a reactor,
In a nitrogen atmosphere, raise the temperature to 120 ° C and generate TMAC with a nitrogen content of 50 ppm with respect to the curing agent and 12.5% of meta-xylenediamine.
Parts (2.5% by weight relative to the amount of hardener produced) were added.

When the temperature reached 130 ° C, xylene and water were distilled off under reduced pressure, and then the reaction was carried out at 130 ° C for 6 hours in a nitrogen atmosphere.

After the completion of the reaction, 25.3 parts of 2-methylimidazole (4.8% by weight based on the amount of the generated curing agent) was added and mixed with stirring to obtain a product.

The hardener produced is clay (GH) at a softening point of 86 ° C and 25 ° C.
The physical property of T was given.

Test Examples The resins shown in Table 1 below were used as the main ingredients, and Examples 1 to 3 were used.
It was cured with the curing agent obtained in (1) and the physical properties of the obtained cured product were examined.

The physical properties of the respective curing agents obtained in Examples 1 to 3 used as the curing component were as shown in Table 2 below.

As the hardener composition, those containing 2MZ (2-methylimidazole) in addition to the hardener components of Examples 1 to 3 were used. The blending amount is shown in Table 3 below.

The curing agent composition thus obtained was blended with the above-mentioned main component to prepare a cured product. The compounding ratio is the curing agent composition A, B, C
And the thing of the ratio of the following Table 4 was prepared according to the comparative example.

For each sample of the above mixing ratio, the following varnish conditions,
Impact test, Erichsen,
A cross-cut test was conducted.

(Varnish conditions) Solvent: 1. Methyl cellosolve / toluene / n-butanol = 3 /
5/2 2.MIBK / Cyclohexanone / Product Name Solvesso ^* # 100 ＝
5/3/2 3. Xylene / n-butanol = 7/3 *: Esso Standard Co., Ltd. Film thickness: 4-6μ, 9-12μ Varnish viscosity: Approx. 330,500cps (room temperature) Test panel: Zinc-plated iron plate surface Plate-shaped body treated with zinc phosphate (curing conditions) Cured at 270 ° C x 60 seconds or 270 ° C x 90 seconds.

(Measurement conditions) DuPont impact: 1 kg load x 30 cm, 1/2 inch.

Erichsen: 5mm width cut, 6.5mm extrusion.

Cross pattern: 1 mm width and 100 squares are displayed.

Impact value: DuPont impact, 1kg x 50cm, peel off cellophane tape,
The value indicated by the electrical conductivity of the coating film.

* All boiling tests were performed by conducting a DuPont, Erichsen, and cross-cut and then boiling for 1 hour.

The gelation time was measured as follows.

1. Preparation of sample The main ingredient and curing agent are crushed, melt-kneaded on a hot plate at 130 ° C for 2 minutes, cooled and crushed to obtain a sample.

2.Measurement method 2-1 Use a heating device (trade name: Hotcon, manufactured by Nisshin Kagaku) 16
Control at 0, (180,200) ± 1 ℃ and check with a surface thermometer.

2-2 Put about 20 mg of the sample in the recess of the hot con, and immediately press the stopwatch to start timing.

2-3 Stir without interruption with a glass rod (with a thin tip).

2-4 When the end point is near, pull up the glass rod by about 1 cm, make the end point when it breaks, and immediately press the stopwatch to set the number of seconds as the gelation time.

The glossiness was measured as follows.

1. Gloss meter VG-1PD (manufactured by Nippon Denshoku Co., Ltd.)
Is stabilized by a predetermined operation (zero alignment and standard alignment).

2. Set the test panel with the specified film thickness on the gloss meter and display the reading at that time.

The impact test was measured as follows.

1. A test panel with a coating film of a specified thickness is 3 cm x 5 cm
Cut into pieces.

2. Bend the cut test panel with the coating side up and Andrell.

3. Using a DuPont impactor, drop a load of 1 kg from a height of 50 cm on the folded surface to give an impact.

4. Boil some test panels.

5. Put cellophane tape evenly on the bent surface of the untreated and boiled plate, and peel it off at once.

6. This test panel is dipped in a 2% sodium carbonate solution, a voltage of 6 V is applied between the test panel and an electrode prepared separately, and the current value on the cellophane tape peeling surface is read.

7. The current value of the test panel without the coating is used as a blank, and the duty ratio (%) is calculated by the formula of sample current value / blank current value × 100 = duty ratio and expressed as an impact test value (%).

The measurement results are shown in Tables 5 to 7 below. In addition, in the following measurement results, tests were conducted under different conditions in order to consider the effects of changes in solvent type, curing time, and film thickness.

EFFECTS OF THE INVENTION As can be understood from the results of the above examples, the curing agent of the present invention contains an amine adduct obtained by mixing and reacting a bisphenol, an epoxy compound and a polyvalent amine. The cured product thus cured is excellent in flexibility and heat resistance, especially in hot water resistance. Further, since the curing agent of the present invention can be produced from relatively inexpensive raw materials, it is industrially very useful in terms of cost reduction.

Claims (1)

[Claims] 1. A branched amine adduct having a structure in which a bisphenol having a hydroxyl group is added to the terminal, which is obtained by mixing and reacting a bisphenol, an epoxy compound and a polyvalent amine. Hardener to do.