JPH03221517A - Production of modified epoxy resin - Google Patents

Abstract

PURPOSE:To shorten reaction time and simplify operation by adding bisphenols to a low-molecular bisphenol type epoxy resin and simultaneously subjecting a resin formed by the aforementioned reaction to ring opening polymerization with a lactonic compound. CONSTITUTION:(A) A low-molecular (hydrogenated) bisphenol type epoxy resin having 150-230 epoxy equiv., (B) (hydrogenated) bisphenols (e.g. bisphenol A) and (C) a lactonic compound (e.g. epsilon-caprolactone) are collectively charged to simultaneously carry out reaction for adding the component (B) to the component (A) and reaction for ring opening polymerization of the component (C) with OH groups in the resultant epoxy resin obtained by the above-mentioned reaction in the same reaction process. Thereby, the objective resin is obtained. Furthermore, the aforementioned two reactions are preferably simultaneously conducted by carrying out the reactions in the coexistence of a basic catalyst for adding the bisphenols such as pyridine and a catalyst such as tin octylate for the addition reaction of the lactonic compound.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for producing a modified epoxy resin. More specifically, the present invention provides excellent flexibility obtained by ring-opening polymerization of a lactone compound such as ε-caprolactone to the secondary hydroxyl group of an epoxy resin, and excellent reactivity with a crosslinking agent. The present invention relates to a method for producing a modified epoxy resin having a primary hydroxyl group.

Epoxy resins, particularly glycidyl ether type epoxy resins produced from bisphenol A and epichlorohydrin, are available in various varieties ranging from liquid to high molecular weight solid resins, and are used for a variety of purposes.

Among them, low-molecular-weight liquids are cured at room temperature with polyamines and polyamide resins by utilizing the reactivity of their engineered boxy groups, and are used in adhesives, FRP, flooring materials, etc., and polybasic acid anhydrides. By heating and curing, it is used mainly for electrical applications such as cast products.

On the other hand, those with high molecular weight are brittle solid resins with a melting point of 60 to 150°C, and have secondary hydroxyl groups in addition to terminal epoxy groups, so they are used in various coating fields that utilize reactions of the hydroxyl groups. has been done.

For example, epoxy esters esterified with unsaturated fatty acids are used as air-drying or room-temperature-drying paints, baking paints using melamine resin as a crosslinking agent, and can coatings combined with phenolic resins. .

It is also used in epoxy powder paints by turning it into powder and mixing it with blocked isocyanate.

It is also used in cationic electrodeposition paints, etc.

(Prior art) The conventional method for producing modified epoxy resin involves adding bisphenols to a low-molecular epoxy resin (bisphenol type or hydrogenated bisphenol type) as a first step reaction, and producing an epoxy resin with hydroxyl groups in the molecule. After synthesizing this, a lactone compound was polymerized therein as a second reaction to synthesize a lactone-modified epoxy resin.

In other words, the technique disclosed in JP-A-63-179918 uses a basic catalyst to carry out the first reaction at 170°C for 4 hours, followed by the second reaction for 7 hours. We are continuing to obtain modified epoxy resin.

(Problems to be Solved by the Invention) However, in the above two-step reaction, the lactone compound must be added after checking the reaction time required for each reaction and the degree of progress of the first-stage reaction.

Therefore, there are problems such as the time required for the check, the time required to add the lactone compound, and the time required to raise the temperature because the temperature of the reaction solution temporarily drops when the lactone compound is added, making the total reaction time considerably longer. be.

Further, there are also problems such as the lactone compound must be added to the high temperature reaction solution, making it difficult to operate.

(Object of the Invention) The present invention relates to a method for easily producing a lactone-modified epoxy resin, with the aim of shortening the reaction time and simplifying the operation in the above-mentioned conventional techniques.

(Means for Solving the Problems) The method for producing a modified epoxy resin of the present invention will be specifically explained.

The method for producing the modified epoxy resin of the present invention is the following reaction (A).
and (B) are carried out simultaneously in the same reaction step.

Reaction (A): A reaction in which bisphenols or hydrogenated bisphenols are added to a low-molecular bisphenol-type epoxy resin or a low-molecular hydrogenated bisphenol-type epoxy resin.

Reaction (B): A reaction in which a lactone compound is subjected to ring-opening polymerization to the hydroxyl group in the epoxy resin obtained in the reaction (A).

The low molecular bisphenol type epoxy resin (or hydrogenated bisphenol type epoxy resin) used in the present invention has the following structure.

Shiri3 -0- 1 In addition, bisphenols or hydrogenated bisphenols have the following structure.

centre nine to The compound has the following structure.

[R1R2 is H or C, -C4's 7/lz-! -l group, aryl group, arylene group, n-3 to 9] Two types of catalysts are used: a basic catalyst for adding bisphenols and a catalyst for adding lactone compounds.

Basic catalysts include tertiary amines such as triethylamine, dimethylbenzylamine, and pyridine, quaternary amine salts such as tetramethylammonium chloride, alkali metal hydroxides such as lithium hydroxide and sodium hydroxide, and alkali metals such as lithium chloride. Salt etc. are used.

Examples of catalysts for lactone compound addition reactions include titanium compounds such as tetrabutyl titanate, tetrapropyl titanate, and tetraethyl titanate; organic tin compounds such as tin octoate, dibutyltin oxide, and dibutyltin laurate; and stannous chloride and stannous bromide. 1 tin, stannous iodide, etc. can be used.

The proportion of the lactone moiety in the lactone-modified epoxy resin obtained by the production method of the present invention is 3 to 3 to 1 parts by weight in total.
95 parts by weight are used, preferably 5 to 70 parts by weight.

The reason for this is that if the amount is too small, the desired sufficient flexibility cannot be obtained, and on the other hand, if the amount is too large, the resin becomes too soft.

The molar ratio of low molecular weight epoxy resin to bisphenol is 2:1 to 1:1.

This is a theoretical value so that no unreacted low-molecular-weight epoxy resin remains.

The low-molecular epoxy resin used has an epoxy equivalent of 150 to 230, but those with an epoxy equivalent of less than 150 are not commercially available, and those with an epoxy equivalent of more than 230 result in a solid resin rather than a liquid, which does not meet the purpose of the present invention.

The reaction temperature is 80-240°C, preferably 100-230°C.
Perform at ℃.

If the temperature is lower than 80℃, the reaction rate is low;
This is because if the temperature is higher, lactone compounds such as ε-caprolactone will boil and escape out of the reaction system.

The catalyst concentration is 0.201 to 2000 ppm for the basic catalyst, preferably 0.1 to 500 ppm, and 0.1 to 500 ppm for the lactone addition catalyst, based on the total weight of the epoxy resin, bisphenol (or hydrogenated bisphenol), and lactone compound.
01-11000pp, preferably 0.2-500pp
Do it with m.

The reaction may be carried out without a solvent or in a solvent without active hydrogen such as toluene or xylene.

However, solvents having ester bonds are generally not preferred. This is because, during the reaction, transesterification may occur with the ester groups in the polylactone, resulting in the production of polylactone that is not bonded to the epoxy resin.

The reaction is preferably carried out under an N2 gas atmosphere.

The reason for this is to prevent coloring of the resin.

All raw materials may be added at the same time, or
In order to carry out a more uniform reaction, the epoxy resin, bisphenols, and lactone may be charged, and after the temperature is raised, the catalyst may be added while stirring.

The end point of the reaction is confirmed by sequentially monitoring the epoxy equivalent and the concentration of the remaining lactone compound, but since the rate of disappearance of the lactone compound is slower, it is also possible to monitor only the concentration of the remaining lactone compound.

When the epoxy equivalent and the concentration of the remaining lactone compound fall within a predetermined range, heating is stopped and the product is made into a product.

The lactone-modified epoxy resin of the present invention will be explained below with reference to examples, but the present invention is not limited to these.

In the examples, parts mean parts by weight.

Example 1 Epikote 828 (Yuka Shell Co., Ltd.) 1000 was placed in a 4-tube flask equipped with a nitrogen introduction tube, a thermometer, a cooling tube, and a stirring device.
300 parts of bisphenol A and 1 part of caprolactone
After charging 300 parts and raising the temperature to 120°C, the pressure inside the system was reduced to distill off water. M e 4 N under nitrogen atmosphere
CD (tetramethylammonium chloride) 0
513 parts and 0.026 parts of tetrabutyl titanate were added, and the reaction was carried out at 170°C for 8 hours.

The properties of the obtained epoxy resin were as shown in Table 1.

Example 2 Example 1, without performing depressurization operation, M e 4 N Cf
A similar reaction was carried out using 0.065 parts of 1.

The results of the characteristic values of the obtained epoxy resin were as shown in Table 1.

Comparative Example 1 Into the same apparatus as in Example 1, 1,000 parts of Epicoat 828 and 300 parts of bisphenol A were charged, and after raising the temperature to 120°C, the pressure inside the system was reduced to distill off water.

Under a nitrogen atmosphere, 1'0913 parts of M e 4 N C was added and the reaction was carried out at 170° C. for 1 hour.

The epoxy equivalent at this stage was 488 g/equivalent.

Subsequently, 1,300 parts of monocaprolactone and 0.026 parts of tetrabutyl titanate were added, and the mixture was further heated at 170°C for 9
The reaction was continued for hours to obtain a modified epoxy resin.

Table 1 shows the properties of the obtained epoxy resin.

Comparative Example 2 By the same operation as Comparative Example 1, M e 4N CD was reduced to 0.0
Addition reaction of bisphenol was carried out in 3 hours at 65 parts.

The epoxy equivalent at this stage was 463 g/equivalent.

Subsequently, 1300 parts of ε-caprolactone and 0.026 parts of tetrabutyl titanate were added, and the mixture was further heated at 170°C for 9
The reaction was continued for hours to obtain a modified epoxy resin.

The results of the characteristic values of the obtained epoxy resin were as shown in Table 1. (The following is a blank space) This comparative example shows that there is no difference in the properties of the epoxy resin obtained by the two-stage charging method and the epoxy resin obtained by the batch charging method.

It has also been shown that the -batch charging method has a shorter reaction time than the two-step charging method.

Claims (2)

[Claims] (1) A low-molecular bisphenol-type epoxy resin or a low-molecular hydrogenated bisphenol-type epoxy resin with an epoxy equivalent of 150 to 230, bisphenols or hydrogenated bisphenols, and a lactone compound are charged all at once, and the following reaction (A) is carried out. (A): Reaction and reaction (B) of adding bisphenols or hydrogenated bisphenols to a low-molecular bisphenol-type epoxy resin or a low-molecular hydrogenated bisphenol-type epoxy resin
: Production of a modified epoxy resin, characterized in that a reaction of ring-opening polymerization of a lactone compound to the hydroxyl group in the epoxy resin obtained in the reaction (A) is simultaneously performed in the same reaction step to synthesize a lactone-modified epoxy resin. Method. (2) The production method according to claim (1), wherein the two reactions of bisphenol A addition and lactone addition are carried out simultaneously by coexisting a basic catalyst for bisphenol A addition and a catalyst for lactone addition.