JPH07330748A - Monoalkyl ester of epoxidized substance of (methyl)nadic acid and cross-linking agent - Google Patents

Abstract

PURPOSE:To obtain the subject new compound useful as a cross-linking agent for a thermosetting resin. CONSTITUTION:A monoalkyl ester of an epoxidized substance of (methyl)nadic acid of the formula (R1 and R2 are H or methyl; (n) is 1-4). The compound is obtained by reacting an epoxidized substance of (methyl)nadic acid with a monohydric alcohol in the absence of a catalyst or in the presence of a basic catalyst (e.g. triethylamine). The epoxidized substance of (methyl)nadic acid and the monohydric alcohol are used in the molar ratio of 1:1 to 1:20. In the case of using the basic catalyst, 0.1-20mol% of the basic catalyst is added to the epoxidized substance of (methyl)nadic acid. The reaction temperature is 40-100 deg.C in the case of the absence of a catalyst and 0-80 deg.C in the case of using the basic catalyst, the compound of the formula can readily form an acid anhydride by heating. When the compound of the formula is used as a cross- linking agent for a thermosetting resin, the thermosetting resin has excellent storage stability, the whole compositional components can be made into a one-pack type and the compound of the formula is extremely effective as a cross-linking agent for a thermosetting resin useful especially for a coating compound and an adhesive.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a novel monoalkyl ester of an epoxidized (methyl) naphthic acid which easily forms an acid anhydride upon heating. More specifically, it relates to a crosslinking agent for a thermosetting resin. The present invention relates to a suitable monoalkyl ester of (methyl) naphthic acid epoxidized product.

[0002]

2. Description of the Related Art Generally, a thermosetting resin containing a melamine resin or a polyisocyanate compound as a cross-linking agent is used in a wide variety of applications because of its excellent weather resistance and beauty. However, when a melamine resin is used as a cross-linking agent, the acid resistance is lowered. For example, when this is applied to a paint, there is a drawback that acid rain causes a rain stain on the coating film and the appearance is deteriorated. On the other hand, it has been pointed out that when a polyisocyanate compound is used as a cross-linking agent, the toxicity of the polyisocyanate compound adversely affects the health of workers and other environmental problems.

In order to solve these problems, a cross-linking agent for thermosetting paints, which is an alternative to the melamine resin and the polyisocyanate compound, is required, and a cross-linking agent utilizing a curing reaction between an acid group and an epoxy group is examined. Is being actively conducted.
For example, in JP-A-63-84674, adhesiveness,
Disclosed is a high solid content curable composition containing a low molecular weight polyepoxide, a low molecular weight hydroxyl group-containing polyfunctional substance, a cross-linking agent composed of an acid anhydride, and a curing catalyst as a coating composition having excellent gloss and sharpness. Has been done.

[0004]

However, the above-mentioned cross-linking agent composed of an acid anhydride has a strong chemical activity and is irritating and has a problem that the working environment is impaired.
Further, since the reactivity between the composition components becomes high, the storage stability is poor, and it is difficult to liquefy the entire composition components.
It had a problem of poor workability.

[0005]

DISCLOSURE OF THE INVENTION In view of the above-mentioned problems of the prior art, the inventors of the present invention have diligently studied a crosslinking agent for a thermosetting resin, and as a result, a specific dicarboxylic acid anhydride precursor was found to be
It was found that the dicarboxylic acid anhydride is easily formed by heating, and the present invention has been completed. That is, the monoalkyl ester of the (methyl) naphthic acid epoxidized product, which is the first invention of the present invention, is represented by the following general formula (1).

[0006]

[Chemical 1]

(In the formula, R ₁ and R ₂ are hydrogen or a methyl group, and n is an integer of 1 to 4.) Also, the second invention of the present invention is a crosslinking agent for thermosetting resin. It is characterized by comprising a monoalkyl ester of a (methyl) naphthic acid epoxidized compound represented by the above general formula (1). In addition, in the present invention, the (methyl) naphthic acid epoxidized product indicates a nadic acid epoxidized product or a methylnadic acid epoxidized product.

The monoalkyl ester of the epoxidized (methyl) nadic acid of the present invention can be synthesized by reacting an epoxidized (methyl) nadic acid epoxide with a monohydric alcohol in the absence of a catalyst or a basic catalyst. it can. As the monohydric alcohol, for example, methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, t-butyl alcohol and the like have 1 carbon atom.
Monohydric alcohols of up to 4 can be used. In the present invention, the monohydric alcohols have 1 to 4 carbon atoms, that is, n in the general formula (1) is 1 to 4
Is important. This is because when the number of carbon atoms of the monohydric alcohol is 5 or more, the rate of change of the obtained (methyl) naphthic acid half ester to the acid anhydride decreases to less than 70%.

As the basic catalyst, amines such as triethylamine, tributylamine and dimethylaniline are suitable. The molar ratio of the reactants is anhydrous (methyl) naphthic acid epoxide: monohydric alcohol =
The range is 1: 1 to 1:20, preferably 1: 2.
It is 1: 5. When a basic catalyst is used, the amount thereof added is 0.1 to 20 mol%, preferably 1 to 5 mol%, based on the (methyl) nadic acid epoxide. The reaction temperature is 40 to 100 ° C, preferably 60 to 80 ° C in the case of no catalyst, and 0 to 80 ° C, preferably 40 in the case of using a basic catalyst.
~ 60 ° C.

The monoalkyl ester of the epoxidized (methyl) naphthic acid of the present invention thus obtained has low chemical activity at room temperature, low odor and low irritation, and is a toxic vapor even when heated. Does not occur. Also,
Since the acid anhydride is easily formed by heating, the chemical activity is increased. The monoalkyl ester of epoxidized (methyl) naphthic acid of the present invention has the above-mentioned characteristics, and when used as a cross-linking agent for a thermosetting resin represented by an epoxy group-containing resin, etc. Is extremely good, so that the entire composition can be liquefied. Furthermore, since the double bond portion of (methyl) nadic acid is epoxidized, the thermosetting resin has excellent weather resistance and a high crosslinking density. Therefore, the monoalkyl ester of the (methyl) nadic acid epoxidized product of the present invention is very effective as a cross-linking agent for a thermosetting resin used in paints, adhesives and the like.

When the monoalkyl ester of the epoxidized (methyl) naphthic acid of the present invention is used as a crosslinking agent for thermosetting resins, the rate of conversion to acid anhydride is preferably 80% or more, It is preferably 90% or more. When the rate of conversion to acid anhydride is less than 70%, the curability of the resin tends to be impaired, which is not preferable.

When the monoalkyl ester of the (methyl) naphthic acid epoxidized product of the present invention is used as a crosslinking agent for a thermosetting resin, a catalyst can be used to accelerate curing. For example, when the monoalkyl ester of the (methyl) naphthic acid epoxidized product of the present invention is used as a crosslinking agent for an epoxy resin, a quaternary ammonium salt or a phosphonium salt is preferable. Specific examples thereof include benzyltrimethylammonium chloride, benzyltrimethylammonium bromide, tetrabutylammonium chloride, tetrabutylammonium bromide, tetrabutylammonium hydroxide, benzyltriphenylphosphonium chloride and benzyltriphenylphosphonium bromide.

[0013]

EXAMPLES The present invention will be specifically described below with reference to production examples, examples and comparative examples. All parts in the examples are by weight.・ Evaluation method of rate of change from monoalkyl ester to acid anhydride 140 applied by applying monoalkyl ester to rock salt plate
The rate of change from a monoalkyl ester to an acid anhydride when kept at 30 ° C for 30 minutes was measured by infrared absorption spectrum (characteristic absorption of carboxyl group (2400-3
400 cm ^-1 ) disappears and the characteristic absorption of acid anhydride group (17
80cm ^-1, 1860cm ^-1) is generated. ).

Definition of coating film performance Pencil hardness: According to JIS K-5400 "pencil scratch test". MEK rubbing: Visual appearance judgment after rubbing the coating film with gauze containing MEK (methyl ethyl ketone) -Criteria for visual judgment ○: There is no change in the appearance and excellent coating performance is maintained. Δ: The appearance is slightly inferior. However, there is no problem in practical use x: Appearance is remarkably impaired and practically unusable Acid resistance: A drop of 40% sulfuric acid is spotted on the coating film, dried at 80 ° C. for 15 minutes, and then visually judged.

Criteria for visual judgment ○: There is no change in appearance, and excellent coating performance is maintained. △ to ○: Appearance is slightly inferior, but there is no problem in practical use. △: Appearance deteriorates and there is some problem in practical use. -Δ: Appearance is considerably impaired and there is a problem in practical use ×: Appearance is remarkably impaired and cannot be used in practice Storage stability: 5 resin compositions prepared in Examples and Comparative Examples were used.
Judgment was made based on the change in state after storage at 0 ° C for one week.

◯: No change, ×: Gelation Production Example 1 In a four-necked flask equipped with a thermometer, a stirrer, a condenser, and a temperature control device, an anhydrous nadic acid epoxidized product 180 was added.
And 160 parts of methanol were charged, and the mixture was reacted at 70 ° C. for 6 hours. Infrared absorption spectrum measurement revealed that the characteristic absorption of the acid anhydride group (1780 cm ^-1 , 1860 cm ^-1 ) disappeared, and the characteristic absorption of the carboxyl group (2400-3400 cm ^-1 )
Was confirmed to have occurred, the excess methanol was distilled off under reduced pressure to obtain monomethyl ester (H-1) of a white crystal epoxidized nadic acid. The rate of conversion of the obtained monomethyl ester to an acid anhydride was 95% or more.

Production Example 2 A four-necked flask equipped with a thermometer, a stirrer, a condenser, and a temperature controller was charged with 194 parts of methylnadic acid anhydride epoxidized product and 160 parts of methanol and reacted at 70 ° C. for 6 hours. Infrared absorption spectrum measurement revealed that the characteristic absorption of the acid anhydride group (1780 cm ^-1 , 1860 cm ^-1 ) disappeared, and the characteristic absorption of the carboxyl group (2400-3400c).
m ^-1 ) was generated, and then excess methanol was distilled off under reduced pressure to obtain a colorless liquid monomethyl ester (H-2) of epoxidized methyl nadic acid. The rate of conversion of the obtained monomethyl ester to an acid anhydride was 95% or more.

Production Example 3 A four-necked flask equipped with a thermometer, a stirrer, a condenser, and a temperature controller was charged with 194 parts of methyl naphthic anhydride epoxidized product and 230 parts of ethanol and reacted at 70 ° C. for 6 hours. Infrared absorption spectrum measurement revealed that the characteristic absorption of the acid anhydride group (1780 cm ^-1 , 1860 cm ^-1 ) disappeared, and the characteristic absorption of the carboxyl group (2400-3400c).
After confirming that m ⁻¹ ) was generated, excess ethanol was distilled off under reduced pressure to obtain a colorless liquid monoethyl ester (H-3) of epoxidized methyl nadic acid. The conversion rate of the obtained monoethyl ester to an acid anhydride was 90%.

Production Example 4 A four-necked flask equipped with a thermometer, a stirrer, a condenser, and a temperature control device was charged with 194 parts of methyl naphthic anhydride epoxidized product and 300 parts of n-propanol at 70 ° C.
And reacted for 6 hours. Infrared absorption spectrum measurement, characteristic absorption of acid anhydride group (1780 cm ^-1 , 1860 cm ^-1 )
Disappears and the characteristic absorption of the carboxyl group (2400-34
00 cm ⁻¹ ) was generated, and then excess n-propanol was distilled off under reduced pressure to obtain a colorless liquid monopropyl ester of a methylnadic acid epoxidized product (H-4).
Got The conversion rate of the obtained monopropyl ester to an acid anhydride was 80%.

Production Example 5 A four-necked flask equipped with a thermometer, a stirrer, a condenser, and a temperature control device was charged with 194 parts of methylnadic acid anhydride epoxidized product and 111 parts of n-butanol and reacted at 70 ° C. for 6 hours. . Infrared absorption spectrum measurement revealed that the characteristic absorption of the acid anhydride group (1780 cm ^-1 , 1860 cm ^-1 ) disappeared, and the characteristic absorption of the carboxyl group (2400-340).
After confirming that 0 cm ⁻¹ ) is generated, the excess n
-Butanol was distilled off under reduced pressure to obtain a colorless liquid monobutyl ester (H-5) of epoxidized methyl nadic acid. The conversion rate of the obtained monobutyl ester to an acid anhydride was 75%.

Production Example 6 A four-necked flask equipped with a thermometer, a stirrer, a condenser, and a temperature control device was charged with 194 parts of methylnadic acid anhydride epoxidized product and 122 parts of n-hexanol, and the mixture was heated to 70 ° C.
And reacted for 6 hours. Infrared absorption spectrum measurement, characteristic absorption of acid anhydride group (1780 cm ^-1 , 1860 cm ^-1 )
Disappears and the characteristic absorption of the carboxyl group (2400-34
00 cm ⁻¹ ) was generated, and then excess n-hexanol was distilled off under reduced pressure to give a colorless liquid, a monohexyl ester of a methylnadic acid epoxidized product (H-6).
Got The rate of conversion of the obtained monohexyl ester into an acid anhydride was 20%.

Example 1 20 parts of monomethyl ester (H-1) of the epoxidized nadic acid obtained in Production Example 1, 19 parts of epoxy resin (Epototo YD-128 manufactured by Tohto Kasei Co., Ltd.), tetrabutylammonium bromide A resin composition was prepared by blending 0.78 part. Dilute this resin composition (solvent: xylene,
(Solid content: 60%), applied to a water plate with a bar coater, and baked at 140 ° C. for 30 minutes. Table 1 shows the storage stability of the resin composition and the coating performance of the obtained coating.

Example 2 21 parts of monomethyl ester (H-2) of the epoxidized methyl nadic acid obtained in Production Example 2, 19 parts of epoxy resin (Epototo YD-128 manufactured by Tohto Kasei Co., Ltd.), tetrabutyl bromide A resin composition was prepared by adding 0.8 part of ammonium. Dilute this resin composition (solvent: xylene,
(Solid content: 60%), applied to a water plate with a bar coater, and baked at 140 ° C. for 30 minutes. Table 1 shows the storage stability of the resin composition and the coating performance of the obtained coating.

Example 3 22 parts of the monoethyl ester (H-3) of the methyl nadic acid epoxidized product obtained in Production Example 3, 19 parts of an epoxy resin (Epototo YD-128 manufactured by Tohto Kasei Co., Ltd.), tetrabromide A resin composition was prepared by mixing 0.82 part of butylammonium. This resin composition was diluted (solvent: xylene, solid content: 60%), applied to a water-inspecting plate with a bar coater, and then baked at 140 ° C. for 30 minutes. Table 1 shows the storage stability of the resin composition and the coating performance of the obtained coating.

Example 4 24 parts of monopropyl ester (H-4) of the epoxidized methyl nadic acid obtained in Preparation Example 4, 19 parts of epoxy resin (Epototo YD-128 manufactured by Tohto Kasei Co., Ltd.), tetrabromide A resin composition was prepared by mixing 0.86 part of butyl ammonium. This resin composition was diluted (solvent: xylene, solid content: 60%), applied to a water-inspecting plate with a bar coater, and then baked at 140 ° C. for 30 minutes. Table 1 shows the storage stability of the resin composition and the coating performance of the obtained coating.

Example 5 25 parts of monobutyl ester (H-5) of epoxidized methyl nadic acid obtained in Preparation Example 5, 19 parts of epoxy resin (Epototo YD-128 manufactured by Toto Kasei Co., Ltd.), tetrabromide A resin composition was prepared by mixing 0.88 part of butyl ammonium. This resin composition was diluted (solvent: xylene, solid content: 60%), applied to a water-inspecting plate with a bar coater, and then baked at 140 ° C. for 30 minutes. Table 1 shows the storage stability of the resin composition and the coating performance of the obtained coating.

Comparative Example 1 A resin composition was prepared by mixing 16 parts of a nadic acid epoxidized product, 19 parts of an epoxy resin (Epototo YD-128 manufactured by Tohto Kasei Co., Ltd.) and 0.7 part of tetrabutylammonium bromide. did. This resin composition was diluted (solvent: xylene, solid content: 60%), applied to a water-inspecting plate with a bar coater, and then baked at 140 ° C. for 30 minutes. Table 1 shows the storage stability of the resin composition and the coating performance of the obtained coating.

Comparative Example 2 17 parts of methyl nadic acid epoxidized anhydride, epoxy resin (Epototo YD-128, manufactured by Toto Kasei Co., Ltd.) 19
And 0.72 part of tetrabutylammonium bromide were mixed to prepare a resin composition. This resin composition was diluted (solvent: xylene, solid content: 60%), applied to a water-inspecting plate with a bar coater, and then baked at 140 ° C. for 30 minutes. Table 1 shows the storage stability of the resin composition and the coating performance of the obtained coating.

Comparative Example 3 28 parts of the monohexyl ester (H-6) of the methyl nadic acid epoxidized product obtained in Production Example 6, 19 parts of an epoxy resin (Epototo YD-128 manufactured by Tohto Kasei Co., Ltd.), tetrabromide A resin composition was prepared by blending 0.94 part of butyl ammonium. The storage stability of the obtained resin composition was good. However, when a coating film was formed under the same conditions as in the example, the resin did not cure and the coating film was not formed.

[0030]

[Table 1]

[0031]

INDUSTRIAL APPLICABILITY The monoalkyl ester of (methyl) naphthic acid epoxidized product of the present invention can easily form an acid anhydride by heating, and when used as a crosslinking agent for thermosetting resin, It has excellent storage stability, and it is possible to liquefy all the composition components. Especially, it is very effective as a cross-linking agent for thermosetting resins used in paints, adhesives, etc. It is something.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akio Iwamoto 4-chome, Sunadabashi, Higashi-ku, Aichi Prefecture, Aichi Prefecture 60-62, Product Development Laboratory, Mitsubishi Rayon Co., Ltd. No. 60 Mitsubishi Rayon Co., Ltd. Product Development Laboratory (72) Inventor Shinobu Fujie 4-60 Sunadabashi, Higashi-ku, Nagoya, Aichi Prefecture Mitsubishi Rayon Co., Ltd. Product Development Laboratory

Claims (2)

[Claims] 1. A monoalkyl ester of an epoxidized (methyl) nadic acid having a structure represented by the general formula (1). [Chemical 1] (In the formula, R ₁ and R ₂ are hydrogen or a methyl group, and n is 1
Is an integer of ~ 4. ) 2. A cross-linking agent for a thermosetting resin, which comprises a monoalkyl ester of the epoxidized (methyl) naphthic acid according to claim 1.