JP2002241685A - Method for producing polyphenol resin-containing varnish - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method in which hydrochloric acid generated in a production process of a high-molecular weight polyphenol resin varnish and dissolved in a solvent is efficiently removed. SOLUTION: This method for producing the polyphenol resin-containing varnish is characterized by comprising carrying out condensation reaction of phenol with bischloromethylbiphenyl, bismethoxymethylbiphenyl or bismethylbiphenyl, then removing the unreacted phenol, reacting again with the bischloromethylbiphenyl in the presence of a solvent having low compatibility with water and having >=100 deg.C boiling point, then adding water into the system, dissolving hydrochloric acid remained in the solvent into the water with stirring and then heating to >=100 deg.C to distill away the water containing the hydrochloric acid outside the system.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention provides a cured product having excellent flame retardancy without containing a halogen-based flame retardant or an antimony compound, and contains a polyphenol resin having flexibility enough to form a film. The present invention relates to an efficient varnish production method.

[0002]

2. Description of the Related Art Epoxy resins can be cured with various curing agents to give cured products having generally excellent mechanical properties, water resistance, chemical resistance, heat resistance, electrical properties, etc. It is used in a wide range of fields, such as laminates, molding materials, and casting materials. Conventionally, the most commonly used epoxy resin is a bisphenol A type epoxy resin. As other flame retardants, tetrabromobisphenol A and epoxidized products thereof, and compounds obtained by reacting tetrabromobisphenol A with a bisphenol A type epoxy resin are generally known.
Acid anhydrides and amine compounds are known as curing agents for epoxy resins, but phenol novolak is often used in the field of electrical and electronic components from the viewpoint of reliability.

[0003]

However, the compounds containing bromine as described above are excellent in flame retardancy, but may generate substances that cause environmental pollution during disposal or incineration. Has been pointed out. Antimony compounds used as flame retardant auxiliaries are also concerned about their toxicity. In recent years, the demand for halogen-free and antimony-free epoxy resin compositions has been increasing due to the increasing awareness of environmental protection. Although a cured product of an epoxy resin by phenol novolak is excellent in reliability, the cured product is rigid and lacks flexibility. In recent years, the form of electric and electronic components is not limited to conventional large packages and substrates based on glass fiber,
A sheet-like molded product has been developed in which a solvent is removed after coating in a varnish state on a polyimide, PET film, or metal substrate. In such a case, the resin used is required to have sufficient flexibility. In the case of producing such a resin, hydrochloric acid may be generated in the condensation process. In such a case, a part of the generated hydrochloric acid is dissolved in the solvent. However, when the varnish is applied and dried, the hydrochloric acid diffuses into the air and causes corrosion of the manufacturing apparatus.

[0004]

In view of these circumstances, the present inventors have provided a cured product having excellent flame retardancy, and did not impair the flexibility even when formed into a sheet. As a result of intensive research for a method for producing a polyphenol resin having an extremely low residual amount of hydrochloric acid, the present invention has been completed.

That is, the present invention provides (1) the following formula (1)

[0006]

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(Wherein X represents a methyl group, a chlorine atom or a hydroxyl group) The phenol is usually subjected to a condensation reaction at a ratio of 1.5 to 10 mol, preferably 2 to 8 mol, per 1 mol of the compound. After the (first-stage condensation reaction), unreacted phenol is removed, and the formula (2)

[0008]

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The compound represented by the formula (I) may be used in the presence of a solvent having a low affinity for water and a boiling point of 100 ° C or higher in the range of 0.01 to
After a 0.45 mol condensation reaction (second-stage condensation reaction), and after the completion of the reaction, the temperature in the system is lowered to 100 ° C. or less, water is added to the system, and the hydrochloric acid remaining in the solvent is removed with stirring. And then reheating to 100 ° C. or higher to distill water containing hydrochloric acid out of the system. (2) Used in the second stage condensation reaction Wherein the solvent is at least one selected from the group consisting of propylene glycol monomethyl ether, propylene glycol monopropyl ether and propylene glycol monobutyl ether; (3)

[0010]

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(Where n represents a positive number (average value) of 2 to 20), and the weight average molecular weight determined by GPC (gel permeation chromatography) is 3,000 or more (1) or (1). 2) A method for producing a varnish containing a polyphenol resin described in 2).

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention relates to a compound obtained by reacting a compound of the above formula (1) with phenol (first stage condensation reaction) and a compound of the formula (2) in the presence of a specific solvent. Reaction (second stage condensation reaction). In the first-stage condensation reaction, a catalyst is not particularly required when X is chlorine, but an acid catalyst is used when X is chlorine or methoxy group or hydroxyl group. Examples of the acid catalyst that can be used include hydrochloric acid, sulfuric acid, p-toluenesulfonic acid and the like, with p-toluenesulfonic acid being particularly preferred. The amount of the acid catalyst to be used is generally 0.001 to 0.1 part by weight, preferably 0.005 to 0.05 part by weight, per 1 mol of the compound represented by the formula (1). The phenol is used in an amount of 1.5 to 1 mol per 1 mol of the compound of the formula (1).
It must be in the range of 10 moles. If it is less than 1.5 mol, the molecular weight becomes too large and the viscosity rises, resulting in difficulty in workability. On the other hand, if it exceeds 10 moles, removal of unreacted phenol is too costly and not economical.

The first-stage condensation reaction can be carried out without a solvent or in the presence of a solvent. When a solvent is used, usable solvents include methanol, ethanol, isopropanol, methyl ethyl ketone, methyl isobutyl ketone and the like. The amount of the solvent used is usually 1 to the total weight of the compound represented by the formula (1) and phenol.
It is 0 to 300% by weight, preferably 20 to 250% by weight.

The first-stage condensation reaction is performed while confirming by GPC (gel permeation chromatography) until the compound represented by the formula (1) is completely eliminated. The reaction temperature is usually 40 to 150 ° C, and the reaction time is usually 1 to 10 hours.

After completion of the condensation reaction, if necessary, the acid catalyst is removed by neutralization, washing with water, etc., and then the solvent and unreacted phenol are removed under reduced pressure while heating.

The condensate thus obtained has a structure in which a biphenyl molecule and a phenol molecule are bonded via a methylene bond, and the weight average molecular weight thereof is usually 500 to 1500.
The softening point is usually about 50 to 100 ° C., although it depends on the average molecular weight and cannot be unconditionally determined. Next, the compound represented by the formula (2) is used in an amount of usually 0.01 to 0.45 mol, preferably 0.05 to 0.4 mol, per 1 equivalent of the phenolic hydroxyl group of the obtained condensate. Plus 2
The second stage condensation reaction is performed.

In the second stage condensation reaction, a solvent is used because the viscosity increases as the molecular weight of the product increases. The solvent has a boiling point of 100 ° C or higher, preferably 100 to 20 ° C.
At 0 ° C., those which are inert to acids and have low affinity for water, preferably those having a specific gravity smaller than water are used. Specific examples include propylene glycol monomethyl ether,
Propylene glycol monopropyl ether, propylene glycol monobutyl ether, and the like are mentioned, and one kind or a mixture of two or more kinds is used. The solvent is usually 2-200% by weight, preferably 3-150% by weight, based on the weight of the product.
It is added to the reaction system in advance before the second-stage condensation reaction so as to obtain a weight%, or it is appropriately divided and added during the reaction.

The reaction is carried out while confirming by GPC until the compound represented by the formula (2) completely disappears. The reaction temperature is usually 100 to 180 ° C, and the reaction time is usually 1 to 20 hours.

When a chlorine-containing compound is used as the starting biphenyl compound in the first and second condensation reactions, nitrogen is blown from one side of the reactor and hydrochloric acid generated as a by-product from the other side is used. Take out the gas with a tube. The extracted hydrochloric acid is preferably bubbled and trapped in an alkaline aqueous solution such as an aqueous sodium hydroxide solution. When a compound of the formula (1) in which X is a methoxy group or a hydrogen atom is used as the compound of the first step, methanol or water is produced as the reaction proceeds. To remove it from the system. 2
The target polyphenol resin is obtained by the stage condensation reaction. The polyphenol resin thus obtained is usually represented by the formula (3) and has a polymerization average molecular weight of 30 by GPC.
00 or more.

After the completion of the reaction, the mixture is cooled to 70 to 100 ° C. When the viscosity increases in this temperature range and stirring is difficult, the above solvent is usually used in an amount of 10 to 1 based on the weight of the product.
You may add so that it may become 50 weight%, Preferably it is about 15-100 weight%.

Next, the temperature in the system is lowered to 100 ° C. or less,
While maintaining the temperature at 100 ° C., add warm water under stirring. The amount of hot water is usually 10 to 300% by weight based on the weight of the product.
And preferably 20 to 200% by weight. After sufficient stirring, the temperature is raised from 100 ° C. to the boiling point of the solvent, and water containing hydrochloric acid is removed from the system using a diversion tube. The solvent also flows out at the same time due to azeotrope, but the liquid is separated using a diversion tube, and the solvent is returned to the system.

The above washing step is repeated until the distilled water is close to neutral. Usually, the required number of washings is 2-1.
0 times. The polyphenol resin solution obtained after the completion of the water washing can be used as a target varnish as it is, and the solid content of the above solvent or another solvent is usually 10 to 80% by weight, preferably 20 to 70% by weight. In addition, it is possible to adjust the solution viscosity so that it can be easily handled at room temperature. As the solvent used, for example, γ-butyrolactones, N-methylpyrrolidone (N
MP), N, N-dimethylformamide (DMF),
Amide solvents such as N, N-dimethylacetamide, N, N-dimethylimidazolidinone, sulfones such as tetramethylene sulfone, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, propylene glycol, propylene glycol dimethyl ether, propylene glycol monomethyl ether monoacetate, Ether solvents such as propylene glycol monobutyl ether, acetone, methyl ethyl ketone,
Ketone solvents such as methyl isobutyl ketone, toluene,
And aromatic solvents such as xylene. The varnish of the present invention thus obtained can be suitably used as a curing agent for epoxy resin. A varnish-like composition can be obtained by further adding various epoxy resins and a curing agent to the obtained varnish.

[0023]

Next, the present invention will be described in further detail with reference to Examples. In the following, parts are by weight unless otherwise specified. GPC measurement conditions are as follows. Model: Shodex SYSTEM-21 Column: KF-804L + KF-803L (x2) connected Eluent: tetrahydrofuran (1 ml / min., 40
C) Detector: RI (RI-71S) UV (254 nm; UV-41) Sample: Approximately 0.4% by weight THF solution (100 μl injection) Calibration curve: Use standard Shodex polystyrene

Example 1 A flask equipped with a thermometer, a cooling pipe, and a stirrer was purged with nitrogen gas and subjected to the following formula (4).

[0025]

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121 parts of a compound represented by the formula, phenol 1
88 parts were heated to 130 ° C. under stirring and dissolved. Then, 0.5 parts of paratoluenesulfonic acid was added,
Thereafter, the reaction was carried out for 3 hours while removing generated methanol outside the system using a fractionating tube. After confirming the disappearance of the compound of the formula (4) by GPC, 260 parts of methyl isobutyl ketone was added, followed by washing with water three times, and then heating the oil layer using an evaporator under reduced pressure while heating with methyl isobutyl ketone and unreacted. Was removed to obtain 168 parts of compound (A). The obtained compound (A) has a softening point of 70 ° C. and a melt viscosity at 150 ° C. of 0.8 P
a · s and the hydroxyl equivalent were 203 g / eq. G
It was 960 when the weight average molecular weight was measured using PC.

A flask equipped with a thermometer, a fractionating tube, a cooling tube, a stirrer, and a silicon tube attached to the tip of the cooling tube so that hydrochloric acid gas generated in the container can be driven out of the system is purged with nitrogen gas. Compound (A) 101.5
Parts, 31.4 parts of the compound represented by the formula (2) and 12.4 parts of propylene glycol monobutyl ether. Next, the temperature was raised to 165 ° C. with stirring, and a dehydrochlorination reaction was performed under reflux. The generated hydrochloric acid gas was removed outside the system through a silicon tube. The reaction was followed by GPC analysis, and after confirming that the compound represented by the formula (2) had completely disappeared 3 hours after the start of the reaction, stirring was continued for another 3 hours to terminate the reaction. When the temperature in the system is cooled down to 140 ° C., propylene glycol monobutyl ether 3
An additional 7.1 parts was added to lower the solution viscosity. The temperature in the system was cooled to 90 ° C, 60 parts of 70 ° C hot water was added, and the mixture was stirred at 90 ° C for 30 minutes. Thereafter, the temperature was raised to 165 ° C., and water containing hydrochloric acid and a part of propylene glycol monobutyl ether were distilled out of the system by azeotropic dehydration. Further, liquid separation was carried out using a fractionation tube, water containing hydrochloric acid was removed, and propylene glycol monobutyl ether was returned into the system. Thereafter, similarly, the temperature in the system was lowered to 90 ° C., and 60 parts of 70 ° C. hot water (ion-exchanged water) was added again to perform water washing. This washing step was performed five times. The amount of chlorine in the water distilled off in each washing step was measured by silver nitrate titration, and the results were as shown in Table 1.

Table 1 Number of times of washing The amount of chlorine in the washing water (ppm) 1st 1580 2nd 290 3rd 190 4th 150 5th 90

After the fifth washing with water, the temperature in the system was reduced to 8
The temperature was lowered to 0 ° C., and the mixture was diluted with 74.3 parts of methyl ethyl ketone to obtain 245 parts of a varnish having a solid content of 50%. The obtained polyphenol resin is represented by the formula (3) and the compound is GP
The weight average molecular weight measured using C was 7,800. The total chlorine content in the varnish and the chlorine content in the solid content obtained by evaporating the solvent were measured using a sample combustion apparatus and ion chromatography. As a result, the total chlorine content in the varnish was 90 ppm, and the total chlorine content in the solid content was 140 ppm. When converted from this result, the amount of chlorine contained in the solvent of the varnish was 20 ppm.
Becomes

[0030]

The varnish containing a polyphenol resin according to the production method of the present invention has a very small amount of hydrochloric acid contained in the solvent. Therefore, when a composition is prepared using this varnish and the solvent is evaporated, the production apparatus is Because it does not corrode,
It is extremely useful in a wide range of applications such as molding materials, casting materials, laminate materials, paints, adhesives, resists, and the like.

Claims (3)

[Claims] (1) The following formula (1): (Wherein, X represents any one of chlorine, methoxy group and hydroxyl group). Condensation reaction of phenol in the range of 1.5 to 10 moles with respect to 1 mole of the compound represented by the formula (first stage condensation reaction)
After the reaction, unreacted phenol is removed under reduced pressure by heating, and the compound of the formula (2) A compound having a low affinity for water having a boiling point of 1
A 0.01-0.45 mol condensation reaction (second-stage condensation reaction) is performed in the presence of a solvent at 00 ° C or higher, and after the reaction is completed, the temperature in the system is lowered to 100 ° C or lower, and water is added to the system. Addition of polyphenol resin represented by the formula, wherein the hydrochloric acid remaining in the solvent is dissolved in the water side under stirring, and then heated to 100 ° C. or more again to distill water containing hydrochloric acid out of the system. Varnish production method. 2. The polyphenol resin according to claim 1, wherein the solvent used in the second-stage condensation reaction is at least one selected from the group consisting of propylene glycol monomethyl ether, propylene glycol monopropyl ether and propylene glycol monobutyl ether. Method for producing varnish containing varnish. 3. A polyphenol resin having the formula (3): ## STR3 ## (Where n represents a positive number (average value) of 2 to 20), and the weight average molecular weight by GPC (gel permeation chromatography) is 3,000 or more. Method for producing varnish containing varnish.