JPS6197321A - Manufacturing method of curing agent for epoxy resin - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a curing agent for epoxy resins, and particularly to a method for producing a curing agent for epoxy resins using 2-methylimidazole.

Structures of conventional examples and their problems Epoxy resins are widely used in various industrial fields such as adhesion of a wide range of materials, painting, sealing of electronic parts, and molding materials for impregnation.

Hitherto, latent curing agents such as acid anhydrides, amines, polyamide resins, dicyandiamide, boron trifluoride amine complexes, and imidazole have been used as solid curing agents for such epoxy resins.

When these curing agents are mixed with an epoxy resin and used as an integrated powder composition, they all have the problem that storage stability and curability are not compatible. In other words, curing agents that cure rapidly at low temperatures have poor storage stability, while latent curing agents that have good storage stability have the disadvantage of requiring a long period of time to cure at high temperatures and lacking rapid curing properties at low temperatures. 〇Object of the Invention The present invention overcomes the drawbacks of the solid latent curing agent as described above, and when mixed with an epoxy resin to form an integral powder type composition,
It is an object of the present invention to provide a method for producing a curing agent for epoxy resin which has excellent storage stability and can undergo rapid conversion when heated at a relatively low temperature.

Structure of the Invention The present invention involves heating and mixing 2-methylimidazole and a terbene resin or a xylene resin at a temperature that does not melt the 2-methylimidazole and MF/' the terpene resin or xylene resin, and then cools and solidifies the mixture. A method for producing a curing agent for epoxy resin, which comprises post-pulverization.

2-Methylimidazole has traditionally been used as a rapid curing agent and is a solid material at room temperature with a melting point of 145'C. However, when this material is mixed with an epoxy resin to form an integral powder composition, the storage stability is poor.

Further, terpene resin or xylene resin does not have properties as a curing agent, but has good compatibility with epoxy resin. Therefore, even if these resins are mixed into the epoxy resin, phase separation with the epoxy resin will not occur, and the epoxy resin molded product will not be adversely affected.

According to the present invention, when 2-methylimidazole is combined with a terpene resin or xylene resin that has a lower melting point and has good compatibility with the epoxy resin, the 2-methylimidazole does not melt, and the terpene resin or xylene resin melts. The 2-methylimidazole powder or particles are coated with the terpene resin or xylene resin by heating and mixing at a temperature of Therefore, even when mixed with epoxy powder, there is no contact with 2-methylimidazole or epoxy resin at room temperature, resulting in an integrated powder composition with excellent storage stability. Furthermore, when this composition is heated to a temperature higher than the temperature at which the terpene resin or xylene resin melts, it comes into contact with the 2-methylimidazole or the epoxy resin and can rapidly cure the epoxy resin. Further, since the W&melted terpene resin or xylene resin has good compatibility with the epoxy resin as described above, it does not give a bad impression 11 to the cured composition.

The terpene resin or xylene resin used in the present invention is 2
-Any terpene resin can be used as long as it has a lower melting point than methylimidazole and is solid at room temperature.The terpene resin may be either natural or synthetic.For example, there is Gututa Percha Island Polyisoprene, manufactured by Nippon Zeon Co., Ltd. Finton-1500 (trade name of a synthetic terpene resin) and other terpene and cyclic terpene resins that are compatible with epoxy resins can be used. An example of the xylene resin is Nika/L (trade name) manufactured by Mitsubishi Gas Chemical Co., Ltd.

In producing the curing agent of the present invention, it is preferable to use the curing agent in a ratio of 1 to 5 parts by weight of terpene resin or xylene resin to 1 part by weight of 2-methylimidazole. If the proportion of the terpene resin or xylene resin is less than the above A111, the storage stability of the obtained curing agent will deteriorate when mixed with the epoxy resin, which is undesirable, and if the proportion is greater than the above value, the terpene resin or xylene resin This is not preferable because it slows down the curing speed of the epoxy resin and causes it to lose its rapid curing properties.

Description of examples The present invention will be explained below with reference to a practical example.

Example 1 2-Methylimidazole (manufactured by Saikoku Kasei Kogyo Co., Ltd., trade name 2)
MZ% melting point 145°c) 50ff
, melting point 100° C.), heated to 120° C., stirred once, cooled and solidified, and crushed in a mortar to obtain a powder hardening agent.

Next, 15 parts by weight of the preparation agent prepared as described above was added to 100 parts by weight of bisphenol A type epoxy resin (manufactured by Yuka Shell Co., Ltd., trade name: Ebiko 1001), which is solid at room temperature and has an epoxy weight of 450 to 500. and mixed in a whole mill.

Using this epoxy resin composition, two aluminum plates were bonded together with an area of 2.5 cd, and after curing at 120°C for 20 minutes, the shear adhesive strength was measured using an autograph and found to be 170 V/-. Ta.

Further, the above epoxy resin composition showed no decrease in adhesive strength as a result of an adhesion test even after being stored at room temperature for one month.

Also, the gelation time at 120°C is 1 minute 3 for 1 preparation.
After storage for 1 month at room temperature, the time was 1 minute and 40 seconds, and almost no change was observed for 1.

Example 2 50 parts of 2-methylimidazole (trade name 2MZ) was mixed with 100 parts of xylene resin (manufactured by Mitsubishi Gas Chemical Co., Ltd., trade name dicanol, melting point 70-100°C), and 120 parts of
After heating to °C and stirring uniformly, the mixture was cooled and solidified, and crushed in a mortar to obtain a powder hardening agent.

Next, the epoxy resin is 450 to 500% bisphenol A type epoxy resin (trade name: Pico) 1001, which is solid at room temperature.
) 15 parts by weight of the curing agent prepared as described above was added to 100 parts by weight and mixed in a ball mill.

This epoxy resin composition was used to bond an aluminum plate as shown in Example 1, and the shear adhesive strength after curing at 120°C for 20 minutes was measured and found to be 150 kg/cJ. Further, even after this composition was stored at 5°C for 3 months, no decrease in adhesive strength was observed as a result of an adhesion test.

In addition, the gel time at 120°C was 1 minute 25 at the time of preparation.
Even after storage for 3 months at 5°C, no significant change was observed for 1 minute and 30 seconds.

Table 1 below summarizes the results of Examples 1 and 2.

Table 1 also shows data after storage at room temperature for 1 month and at 5°C for 3 months. Table 1 also shows a comparative example in which 2-methylimidazole was used as it was without using terpene magnetic resin or xylene resin. Effect of the invention As mentioned above, when the curing agent according to the present invention is used, 12
It is possible to obtain an epoxy resin composition that can be cured at 0° C. in about 20 minutes and has excellent storage stability. On the other hand, in the comparative example, when low-temperature rapid curing at 120°C for 20 minutes is performed, the pot life is shortened to 2 to 3 days at room temperature, and the pot life is about 1 month at room temperature. It is clear that the curing agent of the present invention is superior because the reaction conditions (curing conditions) are 150 to 170°C for several hours, requiring high temperature and long time.

Claims (1)

[Claims] 1,2-Methylimidazole and terpene resin or xylene resin are heated and mixed at a temperature that does not melt 2-methylimidazole but melts terpene resin or xylene resin, cooled to solidify, and then pulverized. A method for producing a curing agent for epoxy resin.