JPH0262134B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a method for producing an imide ring-containing epoxy resin. [Prior Art] In order to improve the heat resistance and rigidity of epoxy resins, attempts have been made to introduce imide rings into the molecular skeleton. However, they are either a prepolymer type made by reacting a general-purpose epoxy resin (for example, glycidyl ether of bisphenol A, etc.) with a curing agent having an imide skeleton, or they are made by epoxidizing an imide compound having a terminal double bond such as an allyl group with a peracid. There have been almost no reports of polyfunctional (trifunctional or higher) imide polymers or amide-imide polymers having direct epoxy ends. This is because the inherent imide skeleton is extremely weak and easily hydrolyzed by the base used for epoxidation, and a fully satisfactory product could not be obtained. In extreme cases, the carboxylic acid groups and amino groups produced by hydrolysis cause the painstakingly added epoxy groups to undergo a curing reaction, resulting in gelation, resulting in a product that is completely unusable. [Purpose of the Invention] Therefore, the present inventors aimed to overcome these difficulties and obtain a method for producing an imide ring-containing epoxy resin in which hydrolysis and side reactions of epoxy groups are reduced.
As a result of various studies, we have arrived at the present invention. That is, the gist of the present invention is a method for producing an imide ring-containing epoxy resin, which is characterized by reacting an aromatic imide compound having at least one active hydrogen with epihalohydrin, and then closing the ring with a bicyclic amidine compound. [Structure of the Invention] The present invention will be described in detail below. First, at least one of the
In the aromatic imide compound having active hydrogen, the groups having active hydrogen include -NH ₂ group, -
Examples include OH group, -COOH group, -SH group, and the like. Such an imide compound is obtained by reacting an amino compound having active hydrogen with a polycarboxylic acid or a derivative thereof having the ability to form an imide ring.
That is, for example, (i) an aromatic diamine and an aromatic tri- or tetracarboxylic acid or a derivative thereof; (ii) -
Aromatic monoamine having OH, -COOH, -SH group and aromatic polycarboxylic acid or derivative thereof, (iii)-
Examples include a combination of an aromatic dicarboxylic acid having an OH, -COOH, or -SH group or a derivative thereof and an aromatic mono- or polyamine. Aromatic amino compounds having active hydrogen include aromatic monoamines such as (O-, m-, p-) aminophenol, aminobenzoic acid, aminocresol, aminosalicylic acid, and anthranilic acid;
Or the general formula () H ₂ N-Ar-NH ₂ () (in the formula, Ar represents a divalent aromatic organic group). Aromatic diamines represented by, for example, 4,4'-diaminodiphenylpropane, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfone ,
4,4'-diaminodiphenylsulfone, 4,
4'-diaminodiphenyl ether, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, 3,
3'-diethyl-4,4'-diaminodiphenylmethane 3,3'-dimethoxy-4,4'-diaminodiphenylmethane, methylenebisanthranilic acid, 3,
3'-dimethyl-4,4'-diaminodiphenyl ether, 3,3'-diethoxy-4,4'-diaminodiphenylsulfone, 3,3'-diethyl-4,
4'-diaminodiphenylpropane, 3,3'-dimethyl-4,4'-diaminobenzophenone, 3,
3'-diaminodiphenylmethane, 3,3'-diaminodiphenyl ether, 2,4-diaminotoluene, 2,6-diaminotoluene, 2,4-diaminoanisole, 2,4-diaminomonochlorobenzene, 2,4-diamino Fluorobenzene, m-phenylenediamine, p-phenylenediamine,
Examples include 3,3'-diaminobenzophenone, 1,3-bis(3-aminophenoxy)benzene, and 9,9-bis(4-aminophenyl)fluorene. On the other hand, examples of carboxylic acids having imide ring forming ability include 3,3',4,4'-benzophenonetetracarboxylic acid, pyromellitic acid, 2,3,6,7-naphthalenetetracarboxylic acid, 3,3' , 4,4'-diphenyltetracarboxylic acid, 2,2-bis(3,
4-dicarboxyphenyl)propane, bis(3,4-dicarboxyphenyl)propane, bis(3,4-dicarboxyphenyl)ether,
2,6-dichloronaphthalene-1,4,5,8-
Tetracarboxylic acid, 1,1-bis(2,3-dicarboxyphenyl)methane, bis(3,4-dicarboxyphenyl)sulfone, 1,1,1,
3,3,3-hexafluoro-2,2-bis(3,
Examples include 4-dicarboxyphenyl)propane, trimellitic acid, hydroxyphthalic acid, and the like.
These carboxylic acids can be used in the form of derivatives such as lower alkyl esters and anhydrides, but preferably have the general formula (or () (In the formula, Ar' is a tetravalent aromatic organic group, each of the four carbonyl groups is directly bonded to another carbon atom, and each pair of carbonyl groups is bonded to the adjacent carbon atom in the Ar' group. Ar'' is a trivalent aromatic organic group, each of the three carbonyl groups is directly bonded to a different carbon atom, and a pair of carbonyl groups are bonded to adjacent carbon atoms in the Ar'' group. A tri- or tetracarboxylic acid anhydride represented by The aromatic imide compound having at least one active hydrogen, which is one of the starting materials of the present invention, is prepared by combining the above two components with N,N-dimethylformamide, N,N-dimethylformamide and N,N-dimethylformamide.
- in polar solvents such as dimethylacetamide, N-methyl-2-pyrrolidone, m-cresol etc.
It can be easily obtained by heating at 250°C for 2 to 8 hours. As an example, if an aromatic diamine represented by the above general formula () and a polycarboxylic acid anhydride represented by the general formula () or () are used, and the aromatic diamine is in excess, the amino group represented by the general formula () is used. An imide compound having the following is obtained. [In the formula, Ar, Ar′, Ar″ have the same meanings as in the general formulas (), () and (), and n and m are 0 or a positive integer. However, n+m>0.] Then The obtained aromatic imide compound having active hydrogen is epoxidized with epihalohydrin, which involves an addition reaction of epihalohydrin,
The reaction is carried out in two stages of dehalogenation reaction of the adduct. First, in the first stage addition reaction, the epihalohydrin used has the general formula () (wherein, X is a halogen atom and R is a hydrogen atom or an organic group) is used. For example, epichlorohydrin, β-mether epichlorohydrin, β
-ethyl epichlorohydrin, β-phenyl epichlorohydrin, and the like. This reaction epoxidizes 1 to 4 hydrogen atoms on the diamine group. Although it is possible to epoxidize only a portion of the amine hydrogens, in order to ensure the stability of the epoxy product, it is desirable to epoxidize all four amine hydrogens, that is, the entire amount. Generally, 1 mol or more of epihalohydrin is reacted with 1 mol of the diamine compound, preferably at a ratio of 4 mol or more. In addition, for the reaction, formic acid,
Organic carboxylic acids such as acetic acid, propionic acid, butyric acid can be present. Furthermore, a quaternary ammonium salt or a lithium compound such as lithium hydroxide, lithium chloride, or lithium acetate may be used together with the organic carboxylic acid as a reaction promoter. The amount of organic carboxylic acid used in this case is 50 to 2000% by weight, preferably 100 to 800% by weight, based on the diamine compound. Although this first-stage addition reaction can be carried out without a solvent, a solvent may be used in view of the smoothness and uniformity of the reaction. Solvents that can be used include N,N-dimethylformamide, dimethylsulfoxide, N-methylcaprolactam, N,N-dimethylacetamide, N
-Methyl-2-pyrrolidone, hexamethylphosphoramide, tetramethylene sulfone, butyrolactone and the like. The amount of solvent is not particularly limited, but is generally 0 to 20% relative to the diamine compound.
(by weight) times, preferably 0 to 10 times (by weight). Although the reaction temperature can be raised to the boiling point of the solvent or epihalohydrin, it is generally desirable to carry out the reaction between room temperature and 100° C. or lower in order to suppress side reactions.
This epihalohydrin adduct is poured into a lower alcohol such as methanol or ethanol to uniformly dissolve it, and then slowly poured into a large amount of water to precipitate it. Washing and filtration are repeated several times with a large amount of alcohol/aqueous solution to isolate the epihalohydrin adduct of the diamine. Subsequently, a dehydrohalogenation reaction is performed using a base to close the ring. The base used in this dehydrohalogenation reaction includes bicyclic bases such as 1,8-diazabicyclo[5,4,0]undecene-7, 1,5-diazabicyclo[4,3,0]nonene-5, etc. Use amidines. For example, the epihalohydrin adduct is resolvated in the solvent used in the first stage addition reaction, and the dehydrohalogenation reaction is performed with a bicyclic amidine. The amount of solvent is not particularly limited, but is 0 to 100 times (by weight), preferably 5 to 100 times the amount of the epihalohydrin adduct.
20 (weight) times the amount used. The bicyclic amidine can be added as is or as a solution dissolved in a solvent. The amount of bicyclic amidine used is generally from 2 to 10 mol, preferably from 4 to 10 mol, per mol of epihalohydrin adduct.
6 moles are used. The reaction temperature is preferably room temperature to 100°C, preferably room temperature to 60°C. After the reaction is complete, the solid substance can be isolated with a precipitation solution and used as is as an epoxy resin, but
Furthermore, by adding organic carboxylic acid anhydride,
Any small amounts of bicyclic amidine remaining in the product can be removed. Examples of the organic carboxylic anhydride include acetic anhydride, propionic anhydride, butyric anhydride, and acid anhydrides represented by the above general formula []. The organic carboxylic acid anhydride used is 2 to 100 mol per mol of the amino compound such as diamine,
Preferably 10 to 50 mol is used. The treatment conditions may be one hour or less at room temperature. If the product is obtained in solid form after treatment, it can be used as it is as an epoxy resin, but if it is obtained in solution form, it can be isolated in solid form using a precipitation solvent.
Precipitation solvents include methanol, ethanol, acetone, ethyl acetate, methyl cellosolve,
Benzene, toluene, xylene, cyclohexane, water, etc. can be used. For example, when an imide compound represented by the general formula () is used, the resulting imide ring-containing epoxy resin has the general formula (). [In the formula, Ar, Ar′, Ar″, n, and m mean the above definitions, and Y ¹ , Y ² , Y ³ and Y ⁴ are hydrogen atoms,

[expression] or

[Formula] (R and X mean the above definitions). However, at least one of Y ¹ , Y ² , Y ³ and Y ⁴

〔Example〕

Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited thereto. <Production of active hydrogen-terminated imide compound> Reference example 1 (Imide compound A) The inside of a 500ml four-necked flask equipped with a dropping funnel, thermometer, air-cooled condenser, and stirrer was purged with nitrogen, and 57.6 g of purified 2,4-diaminotoluene was added.
(0.45mole) and dry N-methyl-2-pyrrolidone
I added 180ml. Thereafter, the temperature was raised to 200°C while nitrogen was flowing. Purified 3,3',4,4'-benzophenonetetracarboxylic dianhydride [hereinafter abbreviated as BTDA] 48.3
g (0.15mole) of N-methyl-2-pyrrolidone
The solution was dissolved in 180 ml and added dropwise through a dropping funnel. The temperature inside the system dropped to 175℃, but by expelling the generated water out of the system, the temperature gradually rose and reached 205℃. The solvent was gradually distilled off under reflux and maintained for 4 hours. After cooling, N- was applied at 92℃ and 12mmHg.
160 ml of methyl-2-pyrrolidone was distilled off, and the mixture was cooled to room temperature. The product was poured into 360 ml of demineralized water to separate a precipitate, which was suspended and washed four times with 700 ml of demineralized water, filtered, and dried at 80° C. for 12 hours under reduced pressure to obtain a crude product. Further, this was suspended and mixed in 900 ml of hot acetone for 2 hours for purification. This was dried under reduced pressure at 80°C for 24 hours to obtain an ocher powder. Total amine content of this amine end group-containing imide compound: 3.70×
10 ^-3 eq·mol/g, melting point Tm (DSC method) 288°C, and imidization rate (IR method) 99%. Reference example 2 (Imide compound B) Purified 2,4-diaminotoluene 48g
(0.375mole) and N-methyl-2-pyrrolidone 100
BTDA40.25g (0.125mole) in ml, N-methyl-
170 ml of 2-pyrrolidone solution was added dropwise, and an imide compound was obtained in the same manner as for imide compound A. Next, add 65g (0.625mole) of 35% hydrochloric acid and let it stand at room temperature for 30 minutes.
The mixture was stirred for a minute. Next, 53.8g of sodium acetate
(0.656 mole) was added, and the mixture was further stirred at room temperature for 30 minutes. The reaction product was poured into 600 ml of demineralized water to precipitate. After filtration, suspension washing and filtration were performed several times with a mixed solution of demineralized water and ethanol 1. Then 80℃, 12
Total amine amount 3.10×10 ^-3 eq・
A light brown powder with mol/g, Tm of 270°C, and imidization rate of 99.2% was obtained. Reference Example 3 (Imide Compound C) By the same synthesis method as Reference Example 1, 5 g (0.0253 mole) of 3,3'-diaminodiphenylmethane,
BTDA2.7g (0.0084mole) as N-methyl-2-
The reaction was carried out in 50 ml of pyrrolidone to obtain a gray-white imide compound C. The physical properties (analytical results) of this imide compound C are shown in Table-1. Reference Example 4 (Imide Compound D) 20 g of 3,3'-diaminodiphenylsulfon was prepared using the same synthesis method as Reference Example 1.
(0.0806mole), BTDA8.65g (0.0269mole)
- React in 150 ml of methyl-2-pyrrolidone,
A khaki imide compound D was obtained. Reference Example 5 (Imide Compound E) Purify α by replacing the inside of a 100ml four-necked flask with nitrogen.
-Biphenyltetracarboxylic dianhydride 5g
(0.0170mole) and m-aminophenol 3.9g
(0.0357 mole) was dissolved in 40 ml of dry N-methyl-2-pyrrolidone and heated while flowing nitrogen until the temperature reached
The temperature reached 204℃. Thereafter, the solvent was gradually distilled off in a reflux state and maintained for 6 hours. The mixture was allowed to cool to room temperature to obtain a brown transparent liquid. 800ml of demineralized water,
Pour into a mixture of 200ml of methanol to precipitate,
Suspension washing was carried out twice with the same mixture, further washed several times with methanol, and dried under reduced pressure to obtain an off-white powder with a Tm of 304°C. The yield was 95%, and the purity determined by gel vermiaction chromatography was approximately 100%. Reference Example 6 (Imide Compound F) Purified 2,4-
19.2 g (0.15 mole) of diaminotoluene and dry N,
50 ml of N-dimethylacetamide was added and the mixture was evacuated with nitrogen. When a solution of 21.1 g (0.1 mole) of the 4-acid chloride of trimellitic anhydride dissolved in 100 ml of dry N,N-dimethylacetamide was gradually added dropwise through a dropping funnel at room temperature, an exothermic reaction occurred and the temperature reached 40°C.
reached its maximum temperature. Stirring was continued for 6 hours while keeping the temperature in the system at 30 to 40°C and flowing nitrogen. Thereafter, the air was removed and the mixture was left at room temperature for 15 hours to complete the reaction and produce an amide polymer. As a result of further heating and expelling the generated water from the system using an air-cooled condenser, the system temperature reached 150°C. Thereafter, it was kept in a reflux state for 5 hours. After the product was left to cool, about two-thirds of the N,N-dimethylacetamide was distilled off and poured into a large excess of a stirred solution of demineralized water/ethanol to form a precipitate. Suspension washing several more times,
A purified light ocher powder was obtained by filtration. Infrared analysis (IR) showed the presence of amide and imide groups, and the carboxyl group disappeared. Data regarding the compounds A to F above are shown in Table 1.

【table】

[Table] * Weight average molecular weight in terms of polystyrene by gel permeation chromatography (manufacture of epoxy compounds) Example 1 60 g of imide compound A was placed in a 1000 ml reactor equipped with a thermometer, condenser, nitrogen inlet tube, and stirrer.
(0.111mole) and 328.8g of epichlorohydrin
(3.552 mole) <8 times the equivalent amount> and 300 g of glacial acetic acid were added, and after purging with nitrogen, the mixture was heated and kept at 80°C for 6 hours.
After removing the air and leaving it at room temperature overnight, add ethanol.
500 ml was added, stirred uniformly, and poured into several times the amount of demineralized water.
A small amount of sodium chloride was then added to separate the precipitate from the liquid. Furthermore, it was redissolved in 200 ml of N,N-dimethylformamide and poured into several times the volume of demineralized water to precipitate. The precipitate was suspended and washed several times with demineralized water, filtered, and dried under reduced pressure to obtain a pink powder with a Tm of 225°C. The obtained epichlorohydrin adduct isolate was found to be a product with an addition rate of ~100% without hydrolysis or side reactions by IR, NMR, and GPC. Next, 4.5 g (0.0049 mole) of epichlorohydrin adduct isolate and 50 ml of dry N,N-dimethylformamide were placed in a 100 ml four-necked flask and dissolved, followed by degassing under reduced pressure of 3 mmHg. 1,8-Diazacyclo[5,
4,0] Undecene-7 [hereinafter abbreviated as DBU] 3.45g
(0.0227 mole) <15% excess of the stoichiometrically required amount> was added and warmed to 40° C. for 6 hours. After cooling, acetic anhydride 11.6g (0.1135mole) < 5 DBU
2 moles> was added, and the mixture was stirred at room temperature for 30 minutes. After filtration, the product was poured into a mixed solution of 150 ml of demineralized water and 150 ml of ethanol to precipitate. A small amount of sodium chloride was added to form a precipitate, and the suspension was washed several times with demineralized water and filtered, followed by drying under reduced pressure at 45° C. for 12 hours to obtain a light ocher powder. There is no imide hydrolysis compared to IR. From the NMR spectrum,
The epoxidation rate due to dehydrochloric acid is approximately 90%,
Also, there was no remaining DBU. Physical properties (analysis results)
are shown in Table-2. Example 2 An epichlorohydrin adduct was isolated from imide compound B, epichlorohydrin, and glacial acetic acid in the same manner as in Example 1. From the NMR spectrum, the addition rate of epichlorohydrin to the active hydrogen of the amine was 98%. 20 g of epichlorohydrin adduct isolate in a 300 ml four-necked flask
(0.022 mole) and 15.3 g (0.10 mole) of DBU <15% excess of the stoichiometrically required amount> N,N-dimethylformamide (150 ml) were added all at once. Under nitrogen flow
It was heated to 50°C and kept for 6 hours. After removing the air and leaving it overnight, acetic anhydride 51g (0.050mole) <5 DBU
twice the mole amount was added, and the mixture was stirred at room temperature for 30 minutes. A precipitate was deposited in a mixed solution of demineralized water and ethanol to obtain a light ocher powder. The yield was 92%. There was no hydrolysis of the imide according to IR, and the epoxidation rate was approximately 89% from the NMR spectrum. Example 3 5 g of epichlorohydrin adduct isolated from imide compound C, epichlorohydrin <8 times the equivalent>, and glacial acetic acid in the same manner as in Example 1
(0.0048mole) and DBU3.8g (0.0248mole) <30% excess of the stoichiometrically required amount>, acetic anhydride after dehydrochloric acid reaction from 50ml of N,N-dimethylformamide.
A gray-white powder was obtained by treatment with 10.1 g (0.099 mole) <4 times mole of DBU>. Example 4 20 g of epichlorohydrin adduct isolated from imide compound D, epichlorohydrin <7 times the equivalent amount>, and glacial acetic acid in the same manner as in Example 1
(0.0174mole) and DBU12.2g (0.080mole) <15% excess of the stoichiometrically required amount>, after dehydrochloric acid reaction with 170ml of N,N-dimethylformamide, acetic anhydride
A grayish white powder was obtained by treatment of 40.8 g (0.400 mole) <5 times the mole of DBU>. Example 5 In a 100 ml reactor similar to Example 1, 4 g (0.0084 mole) of imide compound E and 24.8 g of epichlorohydrin were added.
g (0.2688 mole) <16 times the stoichiometrically required amount> and 25 ml of N,N-dimethylformamide were added, and after purging with nitrogen, the mixture was heated and kept at 8φC for 6 hours.
Thereafter, the pressure in the system was reduced to 6 mmHg, and almost all unreacted epichlorohydrin was distilled off. The product was gradually poured into several times the amount of stirring demineralized water to precipitate it, and then the suspension was washed several times with a mixed solution of demineralized water and ethanol, and then filtered. The epichlorohydrin adduct isolate obtained by drying under reduced pressure was a light brown powder. IR and NMR showed that there was no hydrolysis, and the addition rate to active hydrogen was almost 100%. 3 g (0.0045 mole) of epichlorohydrin adduct isolate
DBU1.59g (0.010mole) <15% excess of stoichiometrically required amount>, N,N-dimethylformamide
After adding 30 ml at once, the mixture was heated to 40°C under nitrogen flow and kept for 5 hours. Thereafter, about 2/3 of the amount of N,N-dimethylformamide was distilled off at 40° C. under a reduced pressure of 2 to 3 mmHg. After cooling, acetic anhydride 4.1g (0.04mole)
<4 times the mole of DBU> was added, and the mixture was stirred at room temperature for 20 minutes. A precipitate was deposited in a mixed solution of demineralized water and ethanol to obtain a light brown powder with a Tm of 165°C. More than 96% of the single product was obtained by gel permeation chromatography. The yield was 92.5%. Example 6 A β-methylepichlorohydrin adduct was isolated from imide compound F, β-methylepichlorohydrin <10 times the equivalent amount>, and glacial acetic acid in the same manner as in Example 1. From the NMR spectrum, the addition rate of β-methylepichlorohydrin to amine active hydrogen was 93%. By the same method as in Example 1, 5 g (0.008 mole) of β-methylepichlorohydrin adduct isolate and 6.57 g (0.0432 mole) of DBU
<35% excess of stoichiometrically required amount>, N,N-
After a dehydrochloric acid reaction with 50 ml of dimethylformamide, a light ocher powder was obtained by treatment with 22 g (0.216 mole) of acetic anhydride (5 times mole of DBU).

〔Effect of the invention〕

According to the method of the present invention, hydrolysis of the imide ring and side reactions of the epoxy group are not substantially caused.
An imide ring-containing epoxy resin can be stably obtained.

Claims (1)

[Claims] 1. A method for producing an imide ring-containing epoxy resin, which comprises reacting an aromatic imide compound having at least one active hydrogen with epihalohydrin, and then closing the ring with a bicyclic amidine compound.