JP7454350B2 - Method for producing polybenzoxazole precursor - Google Patents

Description

The present invention relates to a method for producing a polybenzoxazole precursor.

BACKGROUND ART Polybenzoxazole (hereinafter also referred to as "PBO") precursors are attracting attention in the production of electronic components because they provide cured products with excellent heat resistance and electrical insulation properties.

As a method for synthesizing a polybenzoxazole precursor, a method is known in which an aromatic dicarboxylic acid dihalide and bis(o-aminophenol) are reacted in an aprotic polar solvent. In this synthesis method, a halogen component remains in the obtained polybenzoxazole precursor, but when used as an electronic component, it is necessary to reduce the residual halogen from the viewpoint of long-term reliability such as insulation.

In order to reduce residual halogen, a method has been proposed in which a crude polybenzoxazole precursor obtained by reaction is washed with water or an aqueous alkaline solution (Patent Document 1).

Furthermore, a method has been proposed in which water and a non-aqueous solvent are added to the crude product of the polybenzoxazole precursor obtained by the reaction, the mixture is allowed to stand, and then the aqueous layer is separated (Patent Document 2). .

Japanese Patent Application Publication No. 2007-106786 Japanese Patent Application Publication No. 2013-64130

However, in the method of Patent Document 1, in order to sufficiently reduce residual halogen, it is necessary to repeat washing, so a large amount of water or alkaline aqueous solution is required, and there is a problem that a large amount of waste liquid is generated accordingly. . Furthermore, due to the residual halogen contained in the crude product of the polybenzoxazole precursor, the pH of the cleaning solution is less than 7 immediately after the start of cleaning the crude product, but as the cleaning is repeated, the pH increases. There is also the problem that the solubility of the alkali-soluble polybenzoxazole precursor increases and the yield decreases.

On the other hand, in the method of Patent Document 2 as well, in order to sufficiently reduce residual halogen, it is necessary to repeat the separation of the aqueous layer, and as the separation is repeated, the pH of the aqueous layer increases and the polybenzoxazole precursor There is a problem that the solubility of the body increases and the yield decreases.

An object of the present invention is to provide a method capable of suppressing the discharge of waste liquid and obtaining a polybenzoxazole precursor with a sufficiently reduced residual halogen in a high yield.

In a method for producing a polybenzoxazole precursor, the present inventors dissolved the crude product in a specific alcohol to obtain an alcohol solution, and poured this into water or an aqueous organic acid solution to produce a polybenzoxazole precursor. It has been discovered that the above problems can be solved by precipitation, and the present invention has been completed.

The gist of the present invention is as follows.
[1] A step of reacting a dicarboxylic acid dihalide and bis(o-aminophenol) in an aprotic polar solvent to obtain a crude product of a polybenzoxazole precursor;
The obtained crude product of polybenzoxazole precursor is optionally washed with one or more solvents selected from water and methanol, and then washed with one or more solvents selected from primary alcohols (excluding methanol) and secondary alcohols. and adding the obtained alcohol solution to water or an aqueous organic acid solution to precipitate the polybenzoxazole precursor.
A method for producing a polybenzoxazole precursor, comprising:
[2] The method for producing a polybenzoxazole precursor according to [1], wherein the alcohol has 2 or more and 10 or less carbon atoms.
[3] The method for producing a polybenzoxazole precursor according to [1] or [2], wherein the alcohol is an alcohol having two or more oxygen atoms.
[4] The method for producing a polybenzoxazole precursor according to [3], wherein the alcohol is an alcohol having an ether bond.
[5] Adding an alcohol solution to an aqueous solution of one or more organic acids selected from acetic acid, formic acid, and oxalic acid to precipitate polybenzoxazole, the preparation of the polybenzoxazole precursor according to any one of [1] to [4]. Production method.
[6] The method for producing a polybenzoxazole precursor according to [5], wherein the concentration of the organic acid aqueous solution is 50 ppm or more and 500 ppm or less.

According to the present invention, a method is provided in which it is possible to suppress the discharge of waste liquid and to obtain a polybenzoxazole precursor with a sufficiently reduced residual halogen in a high yield.

<Step of obtaining crude product of polybenzoxazole precursor>
The production method of the present invention includes the step of reacting a dicarboxylic acid dihalide and bis(o-aminophenol) in an aprotic polar solvent to obtain a crude product of a polybenzoxazole precursor.

The dicarboxylic acid dihalide is not particularly limited, but dicarboxylic acid dichloride is preferred from the viewpoint of low temperature reactivity.

Examples of the dicarboxylic acid of the dicarboxylic acid dihalide include isophthalic acid, terephthalic acid, 5-tert-butyl isophthalic acid, 5-bromoisophthalic acid, 5-fluoroisophthalic acid, 5-chloroisophthalic acid, 2,6-naphthalene dicarboxylic acid, 4 , 4'-dicarboxybiphenyl, 4,4'-dicarboxydiphenyl ether, 4,4'-dicarboxytetraphenylsilane, bis(4-carboxyphenyl)sulfone, 2,2-bis(p-carboxyphenyl)propane, Dicarboxylic acids with aromatic rings such as 2,2-bis(4-carboxyphenyl)-1,1,1,3,3,3-hexafluoropropane, oxalic acid, malonic acid, succinic acid, 1,2-cyclobutane Examples include aliphatic dicarboxylic acids such as dicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 1,3-cyclopentanedicarboxylic acid, and di(cyclohexane)-4,4'-dicarboxylic acid. Among them, 4,4'-dicarboxydiphenyl ether is preferred. As the dicarboxylic acid dihalide, dichlorides of these dicarboxylic acids are preferred.

Bis(o-aminophenol) includes, but is not particularly limited to, 3,3'-diamino-4,4'-dihydroxybiphenyl, 4,4'-diamino-3,3'-dihydroxybiphenyl, bis(3-amino- 4-hydroxyphenyl)propane, bis(4-amino-3-hydroxyphenyl)propane, bis(3-amino-4-hydroxyphenyl)sulfone, bis(4-amino-3-hydroxyphenyl)sulfone, 2,2- Bis(3-amino-4-hydroxyphenyl)-1,1,1,3,3,3-hexafluoropropane, 2,2-bis(4-amino-3-hydroxyphenyl)-1,1,1, Examples include 3,3,3-hexafluoropropane. Among them, 2,2-bis(3-amino-4-hydroxyphenyl)-1,1,1,3,3,3-hexafluoropropane is preferred.

Aprotic polar solvents include, but are not limited to, amide solvents such as N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), N-methyl-2-pyrrolidone (NMP), and γ- Examples include cyclic ester solvents such as butyrolactone, γ-valerolactone, and γ-caprolactone, acetone, acetophenone, dimethyl sulfoxide (DMSO), and the like. Among them, NMP is preferred.

The method of reaction of dicarboxylic acid dihalide and bis(o-aminophenol) is not particularly limited, and for example, bis(o-aminophenol) is dissolved in an aprotic polar solvent, and then dicarboxylic acid dihalide is added. An example of this method is to stir the mixture. The dicarboxylic acid dihalide may be added in powder form, or may be added in liquid form by dissolving it in a solvent.
After the reaction, a poor solvent such as water or methanol is added to precipitate the crude product of the polybenzoxazole precursor, and the crude product can be recovered by filtration.

The reaction temperature can be, for example, −15° C. or higher and 60° C. or lower.
The reaction time can be 1 hour or more and 24 hours or less.
The dicarboxylic acid dihalide and bis(o-aminophenol) can be used in an amount such that the number of moles of dicarboxylic acid dihalide:the number of moles of bis(o-aminophenol) is 1:0.5 to 1:2.
The total concentration of dicarboxylic acid dihalide and bis(o-aminophenol) in the reaction system can be 5% by mass or more and 50% by mass or less.
The amount of the poor solvent used for precipitation of the crude product of the polybenzoxazole precursor can be 50 parts by mass or more and 1000 parts by mass or less, and 100 parts by mass or more and 500 parts by mass or less, based on 100 parts by mass of the aprotic polar solvent. It is preferably less than parts by mass.

（式中、
Ｘは、４価の有機基であり、ビス（ｏ－アミノフェノール）から２つの－ＯＨ基と２つのアミノ基を除いた構造に相当し、
Ｙは、２価の有機基であり、ジカルボン酸ジハライドから２つのＣ（＝Ｏ）Ｘ（Ｘは、ハロゲン原子である。）を除いた構造に相当し、
ｎは、１以上の整数であり、好ましくは１０以上５０以下の整数であり、より好ましくは２０以上４０以下の整数である。）
で示される繰り返し構造を有するポリベンゾオキサゾール前駆体の粗生成物を得ることができる。 By reaction, formula (1):

(In the formula,
X is a tetravalent organic group, corresponding to a structure obtained by removing two -OH groups and two amino groups from bis(o-aminophenol),
Y is a divalent organic group and corresponds to a structure obtained by removing two C(=O)X (X is a halogen atom) from a dicarboxylic acid dihalide,
n is an integer of 1 or more, preferably an integer of 10 or more and 50 or less, more preferably an integer of 20 or more and 40 or less. )
A crude product of a polybenzoxazole precursor having a repeating structure shown in can be obtained.

<Washing step with poor solvent (optional step)>
The production method of the present invention can include a step of washing the crude product of the polybenzoxazole precursor with a poor solvent such as water or methanol. The amount of the poor solvent used for one washing can be 3 times or more and 100 times or less, and preferably 5 times or more and 50 times or less, by mass, of the crude product of the polybenzoxazole precursor. When cleaning is performed, it is preferable that the number of times of cleaning be small in terms of suppressing discharge of waste liquid.

<Step of obtaining alcohol solution of crude product of polybenzoxazole precursor>
The production method of the present invention is a step of dissolving a crude product of a polybenzoxazole precursor in one or more alcohols selected from primary alcohols (excluding methanol) and secondary alcohols to obtain an alcohol solution. including. The above-mentioned alcohol is a good solvent for the polybenzoxazole precursor, and alcohol that is liquid at room temperature (25° C.) is preferable.

Examples of primary alcohols include ethanol, 1-propanol, 2-methyl-1-propanol, and 1-butanol, and examples of secondary alcohols include 2-propanol and 2-butanol.

From the viewpoint of solubility of the polybenzoxazole precursor, the alcohol is preferably an alcohol having two or more oxygen atoms, and examples thereof include alcohols having two or more hydroxyl groups, alcohols having an ether bond, and the like. Among these, alcohols having an ether bond are more preferred from the viewpoint of yield. Examples of alcohols having two or more oxygen atoms include ethylene glycol, propylene glycol, diethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol mono-n-propyl ether, ethylene glycol monoisopropyl ether, and ethylene glycol mono- n-butyl ether, ethylene glycol mono-isobutyl ether, ethylene glycol mono-sec-butyl ether, ethylene glycol mono-tert-butyl ether, propylene glycol 1-monomethyl ether, propylene glycol 1-monoethyl ether, propylene glycol 1-mono-n-propyl Ether, propylene glycol 1-monoisopropyl ether, propylene glycol 1-mono-n-butyl ether, propylene glycol 1-mono-isobutyl ether, propylene glycol 1-sec-butyl ether, propylene glycol 1-mono-tert-butyl ether, etc. From the viewpoint of yield, ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol mono-n-butyl ether, propylene glycol 1-monomethyl ether and the like are preferred. The above alcohols may be used alone or in combination of two or more.

The concentration of the crude product of the polybenzoxazole precursor in the alcohol solution is preferably 1% by mass or more, more preferably 5% by mass or more, from the viewpoint of chloride ion removal efficiency. The upper limit of the concentration is not particularly limited as long as it is a concentration that dissolves the crude product, and can be, for example, 50% by mass or less.

<Step of adding the obtained alcohol solution to water or organic acid aqueous solution>
The production method of the present invention includes the step of adding the obtained alcohol solution to water or an aqueous organic acid solution to precipitate the polybenzoxazole precursor. Water or an aqueous organic acid solution is a poor solvent for the polybenzoxazole precursor.

From the viewpoint of yield, it is preferable to use an organic acid aqueous solution. Examples of organic acids include, but are not limited to, formic acid, acetic acid, oxalic acid, hydroxypropionic acid, propanoic acid, lactic acid, butyric acid, citric acid, ascorbic acid, etc. Among them, formic acid, acetic acid, and oxalic acid are preferred, and particularly Oxalic acid is preferred. The organic acids may be used alone or in combination of two or more.

The concentration of the organic acid in the organic acid aqueous solution is preferably 10,000 ppm or less, more preferably 1,000 ppm or less, and even more preferably 500 ppm or less, from the viewpoint of insulation reliability of the cured film. In order to fully obtain the effect of using an organic acid, the concentration of the organic acid in the organic acid aqueous solution can be 1 ppm or more, preferably 20 ppm or more, and more preferably 50 ppm or more.
The pH of the organic acid aqueous solution is preferably 7 or less, more preferably 4 or less, from the viewpoint of the yield of the polybenzoxazole precursor.

The method of adding the alcohol solution to water or the organic acid aqueous solution is not particularly limited, and may be added all at once or in parts, but from the viewpoint of removal efficiency of chloride ions, dropwise addition is preferable. preferable. The dropping can be carried out over a period of 10 minutes or more and 600 hours or less, and preferably 30 minutes or more and 300 hours or less.

The amount of water or organic acid aqueous solution can be, for example, 50 parts by mass or more with respect to 100 parts by mass of alcohol solution. In terms of chloride ion removal efficiency, the amount is preferably 500 parts by mass or less, more preferably 200 parts by mass or less.

The temperature during addition can be -10°C or higher and 60°C or lower, preferably 0°C or higher and 30°C or lower.
After the addition is complete, the solution is preferably allowed to stand, and is preferably allowed to stand for 30 minutes or more and 24 hours or less.
After the addition is completed and before the mixture is allowed to stand still, an organic acid or an aqueous organic acid solution may be added to adjust the pH.

The precipitated polybenzoxazole precursor can be recovered by filtration.

The production method of the present invention is a step of dissolving the polybenzoxazole precursor recovered by filtration in one or more alcohols selected from primary alcohols (excluding methanol) and secondary alcohols to obtain an alcohol solution. The step of adding the obtained alcohol solution to water or an aqueous organic acid solution may be repeated, but from the viewpoint of suppressing the discharge of waste liquid, it is preferable to repeat each of these steps two times or less. It is more preferable to carry out the procedure once at a time.

According to the production method of the present invention, a polybenzoxazole precursor can be obtained in a yield of 80% or more. The yield is preferably 90% or more, more preferably 95%. Further, the residual halogen in the obtained polybenzoxazole precursor can be reduced to 30.0 ppm or less. The amount of residual halogen is preferably 20.0 ppm or less, more preferably 7.0 ppm or less.

EXAMPLES Hereinafter, the present invention will be explained in more detail using Examples, but the present invention is not limited thereto. In the following, "parts" and "%" are based on mass unless otherwise specified.

[Example 1]
65 g of N-methylpyrrolidone (NMP) was added to a 300 mL flask and heated to 60°C. Add 9.9777 g (0.02724 mol) of powdered 2,2-bis(3-amino-4-hydroxyphenyl)-1,1,1,3,3,3-hexafluoropropane (6-FAP), Completely dissolved. Furthermore, 10 g of NMP was added, the flask was immersed in an ice bath, and the mixture was stirred until the temperature of the liquid became 10° C. or lower. Next, 1 g of powdered 4,4'-diphenyl ether dicarboxylic acid chloride (DEDC) was added in 1 g increments (0.02982 mol) while keeping the temperature of the liquid below 20°C. After continuing to stir at room temperature (25°C) for 6 hours, 0.32g of ion-exchanged water was added, the temperature was raised to 50°C, the temperature was maintained at 50°C, and the mixture was stirred for 30 minutes. 141 g of methanol was added and stirring was continued until the mixture became homogeneous.
The obtained solution was added dropwise over 2 hours to an 800 mL beaker containing 282 g of ion-exchanged water, and the precipitated solid was filtered using a filter cloth.
The collected solid was added all at once to an 800 mL beaker containing 282 g of ion-exchanged water, stirred at room temperature for 30 minutes, and filtered to collect the solid. This operation was repeated three times.
The entire amount of the obtained solid was added to a 300 mL beaker, and 206 g of propylene glycol 1-monomethyl ether (1-methoxy-2-propanol (PGM)) was added as a good solvent and stirred until completely dissolved.
The obtained solution was added over 2 hours to an 800 mL beaker containing 302 g of ion-exchanged water as a poor solvent and 0.0605 g of oxalic acid as an organic acid. Prior to addition of the solution, the pH of the liquid in the beaker was below 3.
After the addition, 0.183 g of oxalic acid was further added to the 800 mL beaker and left for one day. The solids collected by filtration were dried under reduced pressure at 80° C. to obtain 16.5 g of polybenzoxazole (PBO) precursor. The molecular weight calculated by GPC in terms of polystyrene was Mn: 12,600 and Mw: 30,300. The chlorine concentration determined by ion chromatography was 6.4 ppm.

[Example 2]
A PBO precursor was prepared in the same manner as in Example 1 except that oxalic acid was changed to acetic acid.

[Example 3]
A PBO precursor was prepared in the same manner as in Example 1 except that oxalic acid was not used.

[Example 4]
A PBO precursor was prepared in the same manner as in Example 1, except that propylene glycol 1-monomethyl ether was changed to ethanol.

[Example 5]
A PBO precursor was prepared in the same manner as in Example 1, except that propylene glycol 1-monomethyl ether was changed to ethylene glycol.

[Comparative example 1]
A PBO precursor was prepared in the same manner as in Example 1, except that N-methylpyrrolidone was used as a good solvent and oxalic acid was not used.

[Comparative example 2]
A PBO precursor was prepared in the same manner as in Example 1, except that acetone was used as a good solvent and oxalic acid was not used.

The chlorine concentration and yield were evaluated for Examples and Comparative Examples. Table 1 shows the results.

Evaluation of chlorine concentration was performed as follows.
(1) Using a freeze-pulverizer TI500DX (CMT Scientific), 1.5 g of the PBO precursor was shaken and crushed at 196° C. for 10 minutes.
(2) Solid-phase extraction of 1 g of pulverized PBO precursor using 10 g of ultrapure water (electrical resistance value: 18.2 MΩ) at 121°C for 20 hours in a polytetrafluoroethylene pressure vessel. did.
(3) Ion chromatography measurements were performed on the aqueous solution obtained in (2), and various ion concentrations were calculated using a one-point calibration curve method using a standard solution. The conditions for ion chromatography are as follows.
Ion chromatography: Aquion (trademark) system (manufactured by Thermo Scientific)
Column used: Dionex IonPac (trademark) AS22-Fast (φ4mm x 150mm) (manufactured by Thermo Scientific)
Column temperature: 30℃
Eluent: 1:1 (weight ratio) mixture of _{4.5mM Na2CO3} aqueous solution and 1.4mM _NaHCO3 aqueous solution Eluent flow rate: 1.2mL/min
Standard solution for calibration curve: Anion standard solution for ion chromatography (manufactured by Kanto Kagaku Co., Ltd.)

The evaluation of chlorine concentration is as follows.
◎◎: 7.0ppm or less ◎: More than 7.0ppm and less than 20.0pm ○: More than 20.0ppm and less than 30.0ppm ×: More than 30.0ppm

Evaluation of yield in Examples was performed as follows.
The yield was calculated using the following formula.
Yield [%] =
Weight of PBO precursor in Example [g]/(DEDC weight [g] + 6-FAP weight [g] - HCl weight [g]) x 100
The weight of the PBO precursor is the value measured using an electronic balance of the PBO precursor that is the final product of each example.
DEDC weight and 6-FAP weight are 4,4'-diphenyl ether dicarboxylic acid chloride (DEDC) and 2,2-bis(3-amino-4-hydroxyphenyl)-1,1,1,3 used in the example. , 3,3-hexafluoropropane (6-FAP).
The HCl weight is a value calculated from the amount of chlorine contained in the DEDC used.

Evaluation of yield is as follows.
◎◎: 95% or more ◎: 90% or more and less than 95% ○: 80% or more and less than 90% ×: less than 80%

Comparative Example 1 using N-methylpyrrolidone as a good solvent had a low yield and insufficient reduction in chlorine concentration. Comparative Example 2 using acetone had a low yield.
On the other hand, in Examples 1 to 5, the evaluation results of both yield and chlorine concentration were good. From the results of Examples 1 to 3, it can be seen that even better results can be obtained by using an organic acid aqueous solution as a poor solvent. In the examples, it can be seen that the chlorine concentration can be sufficiently reduced by suppressing the discharge of waste liquid.

[Reference example]
Preliminary experiments regarding solubility and yield were conducted using the solvents shown in Table 2 below.
Regarding solubility, 1 g of the PBO precursor obtained in Example 1 was added to a 50 mL beaker containing a 2 cm Teflon-coated stirring bar, 19 g of the solvent shown in Table 2 below was added, and the conditions were as follows: room temperature: 25°C, rotation speed: 200 rpm The mixture was stirred for 2 hours and visually evaluated.

Evaluation of solubility is as follows.
○: Completely dissolved △: Some gel exists ×: Insoluble

Regarding the yield, 1 g of the PBO precursor obtained in Example 1 was added to a 50 mL beaker containing a 2 cm Teflon-coated stirrer, 19 g of the solvent shown in Table 2 below was added, and the conditions were as follows: room temperature: 25°C, rotation speed: 200 rpm The mixture was stirred for 2 hours. The obtained solution was added dropwise over 3 minutes to 100 mL to which 20 mL of ion-exchanged water had been added, stirred for an additional 10 minutes, and refined for 10 minutes. The solution was filtered using a filter paper whose weight had been measured in advance (circular qualitative filter paper No. 5B, manufactured by ADVANTEC), and the filter paper was dried for 2 hours in a blow drying oven at 85° C., and then the weight was measured. The yield was determined using the following formula.
Yield [%] = (weight after drying [g] - weight of filter paper [g]) ÷ 1 [g] x 100

Evaluation of yield is as follows.
◎: 95% or more ○: 90% or more △: 80% or more -: Not carried out due to insolubility.

From Table 2, it can be seen that the same effects as in Examples can be expected when using solvents Nos. 3, 4, and 7 to 8.

According to the method for producing a polybenzoxazole precursor of the present invention, it is possible to suppress the discharge of waste liquid, and it is possible to obtain a polybenzoxazole precursor with a sufficiently reduced residual halogen in a high yield, making it suitable for industrial use. The above is highly useful.

Claims (5)

Reacting a dicarboxylic acid dihalide and bis(o-aminophenol) in an aprotic polar solvent to obtain a crude product of a polybenzoxazole precursor;
The obtained crude polybenzoxazole precursor is washed with one or more solvents selected from water and methanol, and then washed with one or more solvents selected from primary alcohols (excluding methanol) and secondary alcohols (excluding methanol). a step of dissolving the polybenzoxazole precursor in at least one kind of alcohol to obtain an alcohol solution; and a step of adding the obtained alcohol solution to water or an aqueous organic acid solution to precipitate the polybenzoxazole precursor.
including;
Here, the alcohol is an alcohol having two or more oxygen atoms,
Method for producing polybenzoxazole precursor. The method for producing a polybenzoxazole precursor according to claim 1, wherein the alcohol is an alcohol having 2 or more and 10 or less carbon atoms. The method for producing a polybenzoxazole precursor according to claim 1, wherein the alcohol is an alcohol having an ether bond. The method for producing a polybenzoxazole precursor according to any one of claims 1 to 3, wherein the alcohol solution is added to an aqueous solution of one or more organic acids selected from acetic acid, formic acid, and oxalic acid to precipitate the polybenzoxazole. . The method for producing a polybenzoxazole precursor according to claim 4, wherein the concentration of the organic acid aqueous solution is 50 ppm or more and 500 ppm or less.