JP2892751B2 - Manufacturing method of epoxy resin curing agent - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing an epoxy resin curing agent, and more particularly, to a method for producing a liquid epoxy resin curing agent comprising a mixture of alicyclic dicarboxylic anhydrides. .

BACKGROUND ART The use of alicyclic dicarboxylic anhydrides as curing agents for epoxy resins has been known in the art. Methylnorbornene dicarboxylic anhydride which is liquid at room temperature is generally used as a curing agent for epoxy resins requiring heat resistance.
-28504.

However, since the above-mentioned methyl norbornene dicarboxylic anhydride is produced by thermally decomposing an expensive methylcyclopentadiene dimer into methylcyclopentadiene, and then performing a Diels-Alder reaction with maleic anhydride. In addition, the production cost is high, and it takes a long time to cure the epoxy resin, and the workability is poor.

The present invention aims to solve the problems associated with the prior art such as high production cost and poor workability as an epoxy resin curing agent, and is inexpensive, excellent in workability, and excellent in heat resistance and moisture resistance. It is an object of the present invention to provide a method for producing an epoxy resin curing agent that gives a cured product.

Means for Solving the Problems Summary of the Invention The present inventors are liquid at room temperature, and in examining an inexpensive production method of methyl norbornene dicarboxylic anhydride that gives a cured product having high heat resistance, In a fraction having 6 to 7 carbon atoms obtained by steam cracking a hydrocarbon mixture such as naphtha, methylcyclopentadiene contains 3.5% methylcyclopentadiene.
Paying attention to the fact that it is contained by 5.5% by weight, the Diels-Alder reaction is performed at a specific temperature with maleic anhydride without purifying the fraction, thereby impairing the heat resistance and moisture resistance of the cured product. Not found, and that it is possible to produce an excellent epoxy resin curing agent that is liquid at room temperature,
The present invention has been completed.

That is, the present invention relates to a hydrocarbon fraction containing 6 to 7 carbon atoms obtained by pyrolyzing a hydrocarbon mixture such as naphtha in the presence of steam and containing a diolefin component such as methylcyclopentadiene. Minute and maleic anhydride to produce an acid anhydride epoxy resin curing agent, the reaction is carried out at a temperature of 20 ~ 30 ℃, then
The present invention relates to a method for producing an epoxy resin curing agent, which is performed at a temperature of 75 to 85 ° C.

The method for producing the epoxy resin curing agent according to the present invention will be specifically described below.

In the method for producing an epoxy resin curing agent of the present invention, a fraction having 6 to 7 carbon atoms obtained by steam cracking a hydrocarbon mixture such as naphtha, which is used as a production raw material, and a dicyclopentadiene such as methylcyclopentadiene. The hydrocarbon fraction containing an olefin component usually has the following composition.

Methylcyclopentadiene 3.5-5.5% by weight 1,3-cyclohexadiene 0.5-1.0% by weight 1,3-hexadiene 0.2-1.0% by weight 2-ethyl-1,3-butadiene 0.3-1.0% by weight C ₆ -C ₇ olefin or Paraffin 4.5-8.5% by weight Benzene 40-60% by weight Toluene 20-40% by weight In the method for producing an epoxy resin curing agent of the present invention,
The Diels-Alder reaction is directly performed with maleic anhydride without purifying the hydrocarbon fraction having the above composition. That is, 0.8 to 1.2 mol of maleic anhydride is added to 1 mol of the total of the diolefin components contained in the hydrocarbon fraction having the above composition, and 20 to 30 ° C, more preferably 20 to
0.5 to 3 hours at a temperature of ~ 25 ° C, then raise the temperature to 75
The epoxy resin curing agent of the present invention is produced by performing a Diels-Alder reaction at a temperature of 8585 ° C., more preferably 75-80 ° C. for 1-5 hours.

Here, if the Diels-Alder reaction is performed only at a reaction temperature of 20 to 30 ° C. and the temperature is raised to 75 to 85 ° C. and the reaction is not continued, the yield of the epoxy resin curing agent is extremely reduced, which is not preferable. This means that only 1-methyl and 2-methylcyclopentadiene in the diolefin component methylcyclopentadiene selectively react with maleic anhydride,
This is probably because 5-methylcyclopentadiene and other diolefin components react with maleic anhydride to hardly form the corresponding maleic anhydride adduct.

On the other hand, the Diels-Alder reaction is 75-85 ° C
If carried out at a temperature of, a large amount of heavy substances considered to be based on the polymer is generated, and the yield of the epoxy resin curing agent is lowered, which is not preferable.

In this way, the above-described hydrocarbon fraction containing diolein and maleic anhydride at 20-30 ° C, then at 75-85 ° C
After the Diels-Alder reaction, the unreacted fractions such as benzene and toluene are distilled off, and if necessary, a known catalyst such as a tertiary amine or an alkali metal hydroxide is used. 120-2 under or in the absence
By heating to 00 ° C., a part of endo-methylnorbornene dicarboxylic anhydride, which is a maleic anhydride adduct of methylcyclopentadiene, may be stereoisomerized to the corresponding exo-form. Thereafter, if necessary, the liquid epoxy resin curing agent according to the present invention can be easily produced by performing purification by distillation under reduced pressure.

Furthermore, in the method for producing an epoxy resin curing agent according to the present invention, a polymerization inhibitor such as hydroquinone may be added to the reaction system during the above-described Diels-Alder reaction.

The composition of the epoxy resin curing agent obtained by the method for producing an epoxy resin curing agent according to the present invention is usually End-1-.
Methyl-5-norbornene-2,3-dicarboxylic anhydride is 10 to 50% by weight, endo-5-methyl-5-norbornene-2,3-dicarboxylic anhydride is 25 to 35% by weight, Exo-5-methyl-5-norbornene-2,3-
Dicarboxylic anhydride is from 0 to 40 wt%, bicyclo [2.2.2] -5-octene-2,3-dicarboxylic anhydride is 8-12 wt%, 3-ethyl - [delta ⁴ - tetrahydrophthalic 2 to 6% by weight of acid anhydride, 4-ethyl-Δ
A mixture in which ⁴ -tetrahydrophthalic anhydride is 4 to 8% by weight.

The epoxy resin curing agent produced by the method for producing an epoxy resin curing agent according to the present invention is a mixture having the above-described composition, and therefore has a low freezing point and is liquid at room temperature. It is considered to be excellent in workability such as a reduction in time.

Further, in the present invention, depending on the use of the obtained curing agent, for example, when used in an epoxy resin as a material for optoelectronics, the product may be further subjected to hydrogenation treatment by a conventional method. The resulting product is useful as an epoxy resin curing agent for such applications.

The epoxy resin curable by using the epoxy resin curing agent produced by the method for producing an epoxy resin curing agent of the present invention is a compound having two or more epoxy groups in a molecule, for example, a polyhydric phenol such as bisphenol A. Polyglycidyl ethers of polyhydric alcohols such as 1,4-butanediol; polyglycidyl esters such as phthalic acid and hexahydrophthalic acid; N-glycidyl derivatives of compounds having an amine, amide and heterocyclic nitrogen base; Formula epoxy resin, phenol novolak epoxy resin, orthocresol novolak epoxy resin, and the like.

Further, the curing agent is preferably blended so that the acid anhydride group becomes 0.3 to 1.5 mol, more preferably 0.7 to 1.2 mol, based on 1 equivalent of the epoxy group of the epoxy resin. .

Further, the epoxy resin composition containing the epoxy resin curing agent produced by the method for producing an epoxy resin curing agent of the present invention can be cured as it is, but a tertiary amine, a tertiary amine salt, and a quaternary ammonium salt can be used. It is preferable to use a curing accelerator together with a curing accelerator such as imidazole and a metal salt, since the curing time can be shortened.

Effect of the Invention The method for producing an epoxy resin curing agent of the present invention is a method for producing a diolefin component-containing hydrocarbon fraction containing 6 to 7 carbon atoms obtained from a steam cracker without using an expensive methylcyclopentadiene dimer as a raw material. Use
Since the epoxy resin curing agent is produced at a specific temperature, the epoxy resin curing agent can be produced inexpensively and with high yield.

Further, the epoxy resin agent produced by the method for producing an epoxy resin curing agent of the present invention is liquid at room temperature, and has excellent workability such as a short curing time of the epoxy resin, and the epoxy resin as a cured product thereof. Has excellent properties such as heat resistance and moisture resistance.

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

The percentages and parts in the examples are on a weight basis unless otherwise specified.

Example 1 98 g of maleic anhydride and benzene 1 as a solvent were placed in a three-necked four-necked flask equipped with a reflux condenser and a stirrer.
While maintaining the internal temperature at 20 to 25 ° C., 1,400 g of a hydrocarbon fraction having the following composition obtained by a steam cracker was added dropwise over 1 hour. After that, gradually raise the internal temperature to 80 ° C.
An Alder reaction was performed. Unreacted components were distilled off from the reaction product by distillation to obtain 176 g of a liquid mixture of dicarboxylic anhydride. Then, the mixture of dicarboxylic anhydrides obtained above is subjected to a stereoisomerization reaction from an endo-form to a corresponding exo-form by heating at 170 ° C. for 3 hours, followed by purification by distillation under reduced pressure. As a result, 165 g of a pale yellow transparent liquid was obtained at a yield of 93% based on the diolefin component.

Further, by analyzing the above-mentioned liquid product by gas chromatography, the composition was determined to be endo-1-methyl-.
17.0% of 5-norbornene-2,3-dicarboxylic anhydride
And endo-5-methyl-5-norbornene-2,3
31.7% dicarboxylic anhydride and 3% exo-5-methyl-5-norbornene-2,3-dicarboxylic anhydride.
1.5%, and bicyclo [2.2.2] -5-octene-2,3
-Dicarboxylic anhydride is 9.7%, 3-ethyl-Δ
⁴ -tetrahydrophthalic anhydride is 4.2%,
Ethyl - [delta ⁴ - tetrahydrophthalic anhydride was found to be a mixture is 5.9%.

The viscosity of the liquid product at 25 ° C. was 228 centipoise, and its freezing point was −15 ° C. or less.

90 parts of the epoxy resin curing agent obtained above, 100 parts of epoxy resin (trade name: Epicoat 828, manufactured by Yuka Shell) and 0.5 part of 2-ethyl-4-methylimidazole (manufactured by Shikoku Chemicals) as a curing accelerator are blended at room temperature. And 2 hours at 100 ° C
Subsequently, a curing reaction was performed by heating at 150 ° C. for 5 hours.

The heat distortion temperature of the obtained cured product was 158 ° C. in accordance with JIS K 6911. Further, when the moisture resistance was measured by a pressure cooker test, the weight increase rate was 1.20%. The pressure cooker test measures the weight increase rate after exposing a disk-shaped test piece made of a cured product molded to 70 mmφ x 2 mm t at 122 ° C, 2.2 atm, and 100% humidity for 6 hours. is there.

Steam resulting hydrocarbon fraction of composition methylcyclopentadiene 4.6% by crackers 1,3-cyclohexadiene 0.6% 1,3 Ekisajien 0.2% 2-ethyl-1,3-butadiene 0.3% C ₆ ~C ₇ olefins , Paraffin 6.2% benzene 54.6% toluene 33.5% Example 2 Example 1 except that the stereoisomerization reaction was not performed.
Production of an epoxy resin curing agent was performed in the same manner as described above. The obtained pale yellow transparent liquid was 169 g, and the yield based on the diolefin component was 95%. The composition is analyzed by gas chromatography to find the end-1
-Methyl-5-norbornene-2,3-dicarboxylic anhydride is 48.4%, endo-5-methyl-5-norbornene-2,3-dicarboxylic anhydride is 31.8%, bicyclo [2.2.2 ] -5-octene-2,3-dicarboxylic anhydride is 9.7%, 3-ethyl - [delta ⁴ - tetrahydrophthalic anhydride was 4.2% 4-ethyl - [delta ⁴ - tetrahydrophthalic anhydride Was found to be 5.9%.

The viscosity of the liquid product at 25 ° C was 248 centipoise, and its freezing point was -11 ° C.

Except for using the epoxy resin curing agent obtained above,
A curing reaction and measurement of physical properties of the cured product were performed in the same manner as in Example 1.

As a result, the heat distortion temperature was 159 ° C., and the weight increase rate by the pressure cooker test was 1.23%.

Example 3 An epoxy resin curing agent was produced in the same manner as in Example 1 except that 0.07 g of hydroquinone was added as a polymerization inhibitor together with 98 g of maleic anhydride and 100 g of benzene as a solvent. The obtained pale yellow transparent liquid was 168 g, and the yield based on the diolefin component was 94%. The composition was analyzed by gas chromatography to obtain endo-1-methyl-5-norbornene-2,3.
-17.2% dicarboxylic anhydride and 3% endo-5-methyl-5-norbornene-2,3-dicarboxylic anhydride.
1.8%, exo-5-methyl-5-norbornene-2,3-dicarboxylic anhydride is 31.2%, and bicyclo [2.2.2] -5-octene-2,3-dicarboxylic anhydride is
9.6% 3-ethyl - [delta ⁴ - tetrahydrophthalic anhydride was 4.4% 4-ethyl - [delta ⁴ - tetrahydrophthalic anhydride was found to be a mixture is 5.8%.

The viscosity of the liquid product at 25 ° C. was 225 centipoise, and the freezing point was −15 ° C. or less.

Except for using the epoxy resin curing agent obtained above,
A curing reaction and measurement of physical properties of the cured product were performed in the same manner as in Example 1.

As a result, the heat distortion temperature was 158 ° C., and the weight increase rate by the pressure cooker test was 1.19%.

Comparative Example 1 1,4000 g of the hydrocarbon fraction obtained in the steam cracker used in Example 1 was dropped into a four-necked flask maintained at an internal temperature of 80 ° C. over 1 hour. An epoxy resin curing agent was produced in the same manner as in Example 1 except that the Diels-Alder reaction was performed for 3 hours. A large amount of heavy matter generated by vacuum distillation was removed. 152 g of a pale yellow transparent liquid was obtained at a yield of 85% based on diolefin components.
Was obtained. By analyzing the above product by gas chromatography, the composition was found to be endo-1-methyl-
17.2% of 5-norbornene-2,3-dicarboxylic anhydride
And endo-5-methyl-5-norbornene-2,3
31.7% dicarboxylic anhydride and 3% exo-5-methyl-5-norbornene-2,3-dicarboxylic anhydride.
1.6%, and bicyclo [2.2.2] -5-octene-2,3
-Dicarboxylic anhydride is 9.7%, 3-ethyl-Δ
4.1% of ⁴ -tetrahydrophthalic anhydride;
Ethyl - [delta ⁴ - tetrahydrophthalic anhydride was found to be a mixture is 5.7%.

The viscosity of this liquid product at 25 ° C. was 226 centipoise, and its freezing point was −15 ° C. or less.

Except for using the epoxy resin curing agent obtained above,
A curing reaction and measurement of physical properties of the cured product were performed in the same manner as in Example 1.

As a result, the heat distortion temperature was 158 ° C., and the weight increase rate by the pressure cooker test was 1.20%.

Comparative Example 2 The hydrocarbon fraction obtained in the steam cracker used in Example 1 (14,000 g) was added dropwise to a four-necked flask maintained at an internal temperature of 20 to 25 ° C. over a period of 1 hour. 25 ℃
The epoxy resin curing agent was manufactured in the same manner as in Example 1 except that the Diels-Alder reaction was performed for 10 hours. The obtained pale yellow transparent liquid was 73 g, and the yield based on the diolefin component was 41%. The composition can be analyzed by gas chromatography to determine the end-
1-methyl-5-norbornene-2,3-dicarboxylic anhydride was 23.9%, endo-5-methyl-5-norbornene-2,3-dicarboxylic anhydride was 35.9%, and exo-5- Methyl-5-norbornene-2,3-dicarboxylic anhydride was 35.6%, and bicyclo [2.2.2] -5
Octene-2,3-dicarboxylic anhydride is 0.7%,
- Ethyl - [delta ⁴ - tetrahydrophthalic anhydride is 0.4% 4-ethyl - [delta ⁴ - tetrahydrophthalic anhydride was found to be a mixture of 3.5%.

The viscosity of this liquid product at 25 ° C was 263 centipoise, and its freezing point was -12 ° C.

Except for using the epoxy resin curing agent obtained above,
A curing reaction and measurement of physical properties of the cured product were performed in the same manner as in Example 1. As a result, the heat distortion temperature was 158 ° C., and the weight addition ratio according to the pressure cooker test was 1.20%.

Comparative Example 3 Reagent blade methylcyclopentadiene dimer 16
0 g was introduced into a four-flask having a capacity of 1, and heated to 180 ° C., thereby decomposing and distilling methylcyclopentadiene dimer to obtain 100 g of methylcyclopentadiene. 98 g of maleic anhydride and 100 g of benzene as a solvent were placed in a four-neck flask having a capacity of 3 provided with a reflux condenser and a stirrer.
After introduction, 80 g of the methylcyclopentadiene obtained above was added to 2 g
The solution was dropped from the dropping funnel at 5 to 30 ° C for 1 hour. Thereafter, a Diels-Alder reaction was performed at the same temperature for 2 hours. After completion of the reaction, unreacted methylcyclopentadiene and benzene are distilled off, and then the mixture is heated at 170 ° C. for 3 hours with stirring to perform a stereoisomerization reaction from the endo-form to the exo-form. Purification yielded 166 g of a pale yellow, transparent liquid. The product was analyzed by gas chromatography to find that the composition was such that endo-1-methyl-5-norbornene-2,3-dicarboxylic anhydride was 17.5% and endo-5-methyl-5-norbornene- The mixture was found to be 54.5% 2,3-dicarboxylic anhydride and 28.0% exo-5-methyl-5-norbornene-2,3-dicarboxylic anhydride.

The viscosity of this liquid product at 25 ° C was 272 centipoise, and its freezing point was -11 ° C.

Using the epoxy resin curing agent obtained above, a curing reaction and measurement of physical properties of the cured product were performed in the same manner as in Example 1.
As a result, the heat distortion temperature was 151 ° C., and the weight increase rate by the pressure cooker test was 1.29%. When this epoxy resin curing agent is used, the curing reaction is considered to be slow, and the curing time is 100 ° C. for 2 hours, followed by 150 ° C.
The time was changed to another and the curing reaction was performed again. As a result, the heat distortion temperature of the cured product was 157 ° C., and the weight increase rate by the pressure cooker test was 1.22%.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Hiroshi Ueno 1-3-1, Nishitsurugaoka, Oi-machi, Iruma-gun, Saitama Prefecture Tonen Co., Ltd. (56) References JP 50-159599 (JP, A) JP-A-55-98223 (JP, A) JP-A-63-86717 (JP, A) JP-B-57-28504 (JP, B2) JP-B-44-9370 (JP, B1) (58) (Int.Cl. ⁶ , DB name) C08G 59/42

Claims (1)

(57) [Claims] 1. A hydrocarbon fraction containing 6 to 7 carbon atoms obtained by pyrolyzing a hydrocarbon mixture such as naphtha in the presence of steam and containing a diolefin component such as methylcyclopentadiene. When reacting with maleic anhydride to produce an acid anhydride epoxy resin curing agent,
The reaction is carried out at a temperature of 20-30 ° C., followed by 75-85 ° C.
A method for producing an epoxy resin curing agent, wherein the method is carried out at a temperature of