WO2017135376A1

WO2017135376A1 - Aromatic polysulfone, prepreg, and method for producing prepreg

Info

Publication number: WO2017135376A1
Application number: PCT/JP2017/003802
Authority: WO
Inventors: 新治大友; 松原　政信
Original assignee: 住友化学株式会社
Priority date: 2016-02-05
Filing date: 2017-02-02
Publication date: 2017-08-10
Also published as: ES2930530T3

Abstract

A thermoplastic aromatic polysulfone obtained by polymerizing a dihalogeno compound (A) represented by formula (A) and a divalent phenol (B) represented by formula (B), wherein: the ratio Mw/Mn of the weight-average molecular weight Mw to the number-average molecular weight Mn is at least 1.91; and the number-average molecular weight (Mn) is at least 6,000 and less than 14,000. [In formulas (A) and (B), X and X' each independently represent a halogen atom, R¹, R², R³ and R⁴ each independently represent a C1-4 alkyl group or a C1-4 alkoxy group, n₁, n₂, n₃ and n₄ each independently represent an integer between 0 and 4, inclusive, and when n₁, n₂, n₃ or n₄ is an integer between 2 and 4, inclusive, the multiple R¹, R², R³ or R⁴ may be identical to or different from one another.]

Description

Aromatic polysulfone, prepreg and method for producing prepreg

The present invention relates to an aromatic polysulfone, a prepreg, and a method for producing a prepreg.
This application claims priority based on Japanese Patent Application No. 2016-021124 filed in Japan on February 5, 2016 and Japanese Patent Application No. 2016-180850 filed on September 15, 2016 in Japan. , The contents of which are incorporated herein.

Aromatic polysulfone is not only excellent in heat resistance, chemical resistance, creep resistance, etc., but also has good adhesion to materials such as metal, glass, ceramic, etc., and is therefore used as various coating materials. As an example of such a utilization method, a method of forming a fluororesin coating film on the surface of a substrate by applying an aromatic polysulfone solution containing a fluororesin to a metal substrate and then performing heat treatment is known. ing.

In order for the aromatic polysulfone to have heat resistance suitable for such use, it is important that its molecular weight and molecular weight distribution are in an appropriate range. For example, the number average molecular weight (Mn) is 11,000 to 25000, An aromatic polysulfone having a polydispersity (Mw / Mn) of 3.0 or less is known (see Patent Document 1).

JP 2002-172675 A

Aromatic polysulfone has a high glass transition temperature (Tg) and is therefore used in many fields including the electronic materials field as a material having excellent heat resistance.
However, these aromatic polysulfones are desired to have further improved heat resistance, and there is still room for improvement in order to develop a high glass transition temperature (Tg).
When manufacturing an electronic device, the components of the electronic device may be exposed to high temperatures as in a reflow process, for example. In order to suppress the deformation of parts, it is required to develop a high glass transition temperature (Tg). Moreover, the same problem may arise about the member exposed not only to an electronic device but to high temperature conditions.

The present invention has been made in view of such circumstances, and provides a novel aromatic polysulfone that can exhibit a high glass transition temperature (Tg), a prepreg using the aromatic polysulfone, and a method for producing the prepreg. This is the issue.

In order to solve the above problems, a first aspect of the present invention is a polymerization of a dihalogeno compound (A) represented by the formula (A) and a dihydric phenol (B) represented by the formula (B). A thermoplastic aromatic polysulfone obtained by the above process, wherein the ratio of the number average molecular weight (Mn) to the weight average molecular weight (Mw) (Mw / Mn) is 1.91 or more, and the number average molecular weight (Mn) is An aromatic polysulfone having a molecular weight of 6000 or more and less than 14,000 is provided.

[In the formulas (A) and (B), X and X ′ each independently represent a halogen atom.
R ¹ , R ² , R ³ and R ⁴ each independently represent an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms. n ₁ , n ₂ , n ₃ and n ₄ each independently represents an integer of 0 to 4. When n ₁ , n ₂ , n ₃ or n ₄ is an integer of 2 to 4, a plurality of R ¹ , R ² , R ³ or R ⁴ may be the same or different from each other. ]

The second aspect of the present invention is a prepreg using the aromatic polysulfone of the first aspect of the present invention, a liquid epoxy resin, a curing agent, and reinforcing fibers.
A third aspect of the present invention is a method for producing a prepreg, comprising a step of impregnating a reinforcing fiber into a mixture obtained by mixing the aromatic polysulfone according to the first aspect of the present invention, a liquid epoxy resin, and a curing agent. Is the method.

That is, the present invention includes the following aspects.
[1] A thermoplastic aromatic polysulfone obtained by polymerizing a dihalogeno compound (A) represented by the formula (A) and a dihydric phenol (B) represented by the formula (B),
An aromatic polysulfone having a Mw / Mn which is a value of a ratio of Mn which is a number average molecular weight and Mw which is a weight average molecular weight is 1.91 or more and Mn which is a number average molecular weight is 6000 or more and less than 14,000.

[In the formulas (A) and (B), X and X ′ each independently represent a halogen atom;
R ¹ , R ² , R ³ and R ⁴ each independently represent an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms;
n ₁ , n ₂ , n ₃ and n ₄ each independently represent an integer of 0 to 4;
When n ₁ , n ₂ , n ₃ or n ₄ is an integer of 2 to 4, a plurality of R ¹ , R ² , R ³ or R ⁴ may be the same or different from each other. ]
[2] The aromatic polysulfone according to [1], wherein in the formula (A), X and X ′ are chlorine atoms.
[3] The aromatic polysulfone according to [1] or [2], wherein n ₁ , n ₂ , n ₃ and n ₄ are 0 in the formula (A) or the formula (B).
[4] A prepreg formed from the aromatic polysulfone according to any one of [1] to [3], a liquid epoxy resin, a curing agent, and reinforcing fibers.
[5] Production of a prepreg comprising a step of impregnating a reinforcing fiber into a mixture obtained by mixing the aromatic polysulfone according to any one of [1] to [3], a liquid epoxy resin, and a curing agent. Method.

According to the present invention, it is possible to provide a novel aromatic polysulfone that can exhibit a high glass transition temperature (Tg), a prepreg using the aromatic polysulfone, and a method for producing the prepreg.

<Aromatic polysulfone>
The aromatic polysulfone of the present invention is a thermoplastic obtained by polymerizing a dihalogeno compound (A) represented by the following formula (A) and a dihydric phenol (B) represented by the following formula (B). Aromatic polysulfone having a ratio of number average molecular weight (Mn) to weight average molecular weight (Mw) (Mw / Mn, that is, polydispersity) is 1.91 or more, and number average molecular weight (Mn) is 6000. The aromatic polysulfone is more than 14,000.
In another aspect of the aromatic polysulfone of the present invention, a dihalogeno compound (A) represented by the following formula (A) and a dihydric phenol (B) represented by the following formula (B) are polymerized. Mw / Mn, which is the value of the ratio of Mn, which is the number average molecular weight, and Mw, which is the weight average molecular weight, is 1.91 or more, and Mn, which is the number average molecular weight, is 6000 or more and less than 14,000, A polysulfone.
Still another aspect of the aromatic polysulfone of the present invention is derived from a structural unit derived from a dihalogeno compound (A) represented by the following formula (A) and a dihydric phenol (B) represented by the following formula (B). Mw / Mn which is a value of the ratio of Mn which is a number average molecular weight and Mw which is a weight average molecular weight is 1.91 or more, and Mn which is a number average molecular weight is 6000 or more and less than 14,000. A thermoplastic aromatic polysulfone.
Here, “derived” means that the chemical structure changes because the dihalogeno compound (A) and the dihydric phenol (B) are polymerized.
In the present specification, the dihalogeno compound (A) represented by the formula (A) may be simply referred to as “dihalogeno compound (A)”. Further, the dihydric phenol (B) represented by the formula (B) may be simply referred to as “dihydric phenol (B)”.
The aromatic polysulfone of the present invention has a dihalogeno compound (A) and a dihydric phenol (B) as monomers, and Mw / Mn and Mn satisfy the above conditions, so that a high glass transition temperature can be expressed, and is excellent. Heat resistance.

[In the formulas (A) and (B), X and X ′ each independently represent a halogen atom;
R ¹ , R ² , R ³ and R ⁴ each independently represent an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms;
n ₁ , n ₂ , n ₃ and n ₄ each independently represent an integer of 0 to 4;
When n _1, _n 2, _{n 3} or _{n 4} is an integer of 2 to 4, a plurality of ^R ^1, R 2, ^{R 3} or ^{R 4} may each also being the same or different. ]

[Dihalogeno Compound (A)]
The dihalogeno compound (A) is a compound represented by the formula (A).
In formula (A), X and X ′ each independently represent a halogen atom. Examples of the halogen atom include a chlorine atom, a bromine atom, and an iodine atom, and a chlorine atom is preferable.
X and X ′ are any of 2-position, 3-position and 4-position of the benzene ring skeleton, where the position number of the carbon atom to which the sulfonyl group (—SO ₂ —) of the benzene ring skeleton is bonded is the 1-position. It may be bonded to a carbon atom, but it is preferably bonded to a 4-position carbon atom. That is, the dihalogeno compound (A) is preferably bis (4-chlorophenyl) sulfone to which one or both of R ³ and R ⁴ may be bonded in place of a hydrogen atom.

In the formula (A), R ³ and R ⁴ each independently represent an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms.
The alkyl group in R ³ and R ⁴ may be linear, branched or cyclic, but is preferably linear or branched. Examples thereof include a methyl group and an ethyl group. , N-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, and tert-butyl group.
The alkoxy group in R ³ and R ⁴ may be linear, branched or cyclic, but is preferably linear or branched. Examples thereof include a methoxy group and an ethoxy group. N-propoxy group, isopropoxy group, n-butoxy group, isobutoxy group, sec-butoxy group, and tert-butoxy group.

In formula (A), n ₃ is the number of bonds of R ³ , n ₄ is the number of bonds of R ⁴ , and represents an integer of 0 to 4 independently of each other.
When n ₃ and n ₄ are other than 0, the corresponding bonding position of R ³ or R ⁴ is not particularly limited. When the position number of the carbon atom to which the sulfonyl group of the benzene ring skeleton is bonded is the 1st position, R ³ or R ⁴ is any of the 2nd, 3rd, 4th, 5th and 6th positions of the benzene ring skeleton. It may be bonded to any carbon atom. However, the carbon atom to which X or X ′ is bonded as the bonding position of R ³ or R ⁴ is excluded. R ³ or R ⁴ is preferably attached to a carbon atom other than 4-position, 3-position or 5-position, or more preferably bonded to the 3-position and 5-position carbon atoms.
When n ₃ or n ₄ is an integer of 2 to 4, a plurality of R ³ or R ⁴ may be the same as or different from each other. For example, when n ₃ is an integer of 2 to 4, all n ₃ R ^{3 s} may be the same or different, and when n ₃ is 3 or 4, Only a part may be the same. The number of n ₄ R ⁴ is the same as that of n ₃ R ³ .
n ₃ and n ₄ are preferably each independently an integer of 0 to 3, more preferably an integer of 0 to 2, and even more preferably 0 or 1.

An example of a preferred dihalogeno compound (A) is bis (4-chlorophenyl) sulfone. Bis (4-chlorophenyl) sulfone is also referred to as 4,4'-dichlorodiphenylsulfone.

[Dihydric phenol (B)]
The dihydric phenol (B) is a compound represented by the formula (B).
In the dihydric phenol (B), the two hydroxy groups (—OH) each represent the 2-position of the benzene ring skeleton, when the position number of the carbon atom to which the sulfonyl group of the benzene ring skeleton is bonded is the 1-position. Although it may be bonded to any of the 3-position and 4-position carbon atoms, it is preferably bonded to the 4-position carbon atom. That is, the dihydric phenol (B) is preferably bis (4-hydroxyphenyl) sulfone to which one or both of R ¹ and R ² may be bonded in place of a hydrogen atom. Bis (4-hydroxyphenyl) sulfone is also referred to as 4,4′-dihydroxydiphenylsulfone.

In formula (B), R ¹ and R ² each independently represent an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms. Examples of the alkyl group having 1 to 4 carbon atoms and the alkoxy group having 1 to 4 carbon atoms in R ¹ and R ² include the same groups as those described in the description of R ³ and R ⁴ .
N ₁ is the number of bonds of R ¹ , n ₂ is the number of bonds of R ² , and represents an integer of 0 to 4 independently of each other. When n ₁ and n ₂ are other than 0, the bonding position of the corresponding R ¹ or R ² is not particularly limited. When the position number of the carbon atom to which the sulfonyl group of the benzene ring skeleton is bonded is the 1st position, R ¹ or R ² is any of the 2nd, 3rd, 4th, 5th and 6th positions of the benzene ring skeleton. It may be bonded to a carbon atom. However, as a bonding position of R ¹ or R ² , a carbon atom to which a hydroxy group is bonded is excluded. R ¹ or R ² is preferably bonded to a carbon atom other than the 4-position, and preferably bonded to the 3-position or 5-position, or the 3-position and 5-position carbon atoms.
When n ₁ or n ₂ is an integer of 2 to 4, a plurality of R ¹ or R ² may be the same as or different from each other. For example, when n ₁ is an integer of 2 to 4, all n ₁ R ^{1 s} may be the same or different, and when n ₁ is 3 or 4, R ¹ may be partially identical. The n ₂ R ² is the same as the case of n ₁ R ¹ .
n ₁ and n ₂ are preferably each independently an integer of 0 to 3, more preferably an integer of 0 to 2, and even more preferably 0 or 1.

As the dihydric phenol (B) as another aspect, bis (4-hydroxyphenyl) sulfone and bis (4-hydroxy-3,5-dimethylphenyl) sulfone are preferable.

The reduced viscosity of the aromatic polysulfone of the present invention is preferably 0.18 dL / g or more, more preferably 0.22 to 0.28 dL / g. Aromatic polysulfone tends to improve heat resistance, strength, and rigidity as its reduced viscosity increases. On the other hand, if the aromatic polysulfone has a reduced viscosity that is too high (that is, if it exceeds the upper limit), the melting temperature or the viscosity tends to be high, and the fluidity tends to be low.
That is, when the reduced viscosity of the aromatic polysulfone of the present invention is within the above range, the heat resistance, strength and rigidity are easily improved, the melting temperature and the melt viscosity are not excessively increased, and the fluidity is hardly decreased.

In the present specification, the reduced viscosity (dL / g) of aromatic polysulfone indicates a value determined by the following method. First, about 1 g of an aromatic polysulfone resin is precisely weighed and dissolved in N, N-dimethylformamide to make its capacity 1 dL. Subsequently, the viscosity (η) of this solution and the viscosity (η0) of N, N-dimethylformamide as a solvent are measured at 25 ° C. using an Ostwald type viscosity tube. Next, the reduced viscosity of the aromatic polysulfone is determined by dividing the specific viscosity ((η−η0) / η0) determined from the measured value by the concentration of the solution (about 1 g / dL).

The number average molecular weight (Mn) of the aromatic polysulfone of the present invention is 6000 or more, preferably 6500 or more, more preferably 7000 or more, and further preferably 7500 or more.
Aromatic polysulfone is remarkably excellent in heat resistance because Mn is not less than the lower limit.
The number average molecular weight (Mn) of the aromatic polysulfone of the present invention is less than 14000, preferably 13500 or less, more preferably 13000 or less, further preferably 12500 or less, still more preferably 12000 or less, and particularly preferably 11500 or less. It is.
When Mn is not more than the above upper limit value, the aromatic polysulfone is remarkably excellent in heat resistance.
The upper limit value and lower limit value of Mn can be arbitrarily combined.
The number average molecular weight (Mn) of the aromatic polysulfone of the present invention is, for example, 6000 or more and less than 14000, preferably 7000 or more and 13000 or less, more preferably 7500 or more and 12000 or less, further preferably 7500 or more and 11500 or less, and 8000 to 11000. It is particularly preferred that

In this specification, the value of Mw / Mn, which is the ratio of the weight average molecular weight (Mw) and the number average molecular weight (Mn) of the aromatic polysulfone, indicates the polydispersity of the aromatic polysulfone. In the aromatic polysulfone of the present invention, the value of Mw / Mn is 1.91 or more, preferably 1.92 or more, more preferably 1.93 or more, preferably 2.60 or less, more Preferably it is 2.50 or less, More preferably, it is 2.40 or less.
Aromatic polysulfone can express a high glass transition temperature because the value of Mw / Mn is not less than the lower limit.
The upper limit value and the lower limit value of Mw / Mn can be arbitrarily combined.
In the aromatic polysulfone of the present invention, the value of Mw / Mn is particularly preferably from 1.91 to 2.00, for example.

In this specification, the weight average molecular weight (Mw) and the number average molecular weight (Mn) of an aromatic polysulfone are values obtained by averaging measured values measured twice by gel permeation chromatography (GPC) analysis, for example. is there. In each measurement, the molecular weight in terms of standard polystyrene is obtained based on a calibration curve obtained by measuring the molecular weight of standard polystyrene.

Mw / Mn can be calculated from the weight average molecular weight (Mw) and the number average molecular weight (Mn) obtained as an average value as described above.

The aromatic polysulfone of the present invention can exhibit a high glass transition temperature. For example, when the glass transition temperature is calculated by a method according to JIS-K7121, the glass transition temperature (° C.) in the aromatic polysulfone of the present invention is preferably 215 ° C. or higher, more preferably 216 ° C. or higher. Moreover, as an upper limit of glass transition temperature (degreeC), 235 degrees C or less is preferable. The glass transition temperature (° C.) serves as an index for judging the degree of heat resistance of the aromatic polysulfone. Generally, it can be said that the higher the temperature, the more excellent the heat resistance of the aromatic polysulfone.

[polymerization]
The step of reacting the dihalogeno compound (A) with the dihydric phenol (B) in a solvent (hereinafter referred to as “polymerization”) will be described.
The polymerization of the dihalogeno compound (A) and the dihydric phenol (B) (hereinafter sometimes referred to as polycondensation) is performed using an alkali metal carbonate as a base, or in an organic solvent which is a polymerization solvent. It is preferable to use an alkali metal salt of carbonic acid as a base, and more preferably in an organic solvent.

The alkali metal carbonate may be an alkali carbonate that is a normal salt, that is, an alkali metal carbonate, or an alkali bicarbonate that is an acidic salt, that is, an alkali bicarbonate or an alkali metal bicarbonate. It may be a mixture of these alkali carbonates and bicarbonates.
Preferred examples of the alkali carbonate include sodium carbonate and potassium carbonate.
Preferred examples of the alkali bicarbonate include sodium bicarbonate (also referred to as sodium bicarbonate), potassium bicarbonate (also referred to as potassium bicarbonate), and the like.

The organic solvent is preferably an organic polar solvent.
Examples of the organic polar solvent include dimethyl sulfoxide, 1-methyl-2-pyrrolidone, sulfolane (also referred to as 1,1-dioxothiolane), 1,3-dimethyl-2-imidazolidinone, 1,3-diethyl-2 -Imidazolidinone, dimethyl sulfone, diethyl sulfone, diisopropyl sulfone, diphenyl sulfone and the like.

The amount of dihalogeno compound (A) used in the polymerization is preferably 90 to 105 mol%, and preferably 93 to 100 mol%, based on the amount (mole number) of dihydric phenol (B). More preferably, it is 93 to 99 mol%, more preferably 93 mol% or more and less than 97 mol%. The target reaction (polymerization) is dehydrohalogenated polycondensation of the dihalogeno compound (A) and the dihydric phenol (B). If no side reaction occurs, the molar ratio of both is close to 1: 1. That is, the closer the amount of dihalogeno compound (A) used is to 100 mol% relative to the amount of dihydric phenol (B) used, the higher the degree of polymerization of the resulting aromatic polysulfone. The reduced viscosity tends to increase, Mn increases, and Mw / Mn tends to decrease. However, in fact, side reactions such as substitution reaction of halogen atoms to hydroxy groups and depolymerization occur due to by-produced alkali hydroxide and the like, and this side reaction reduces the degree of polymerization of the aromatic polysulfone obtained. Therefore, in consideration of the degree of this side reaction, it is necessary to adjust the amount of the dihalogeno compound (A) so that an aromatic polysulfone having a predetermined reduced viscosity, Mn and Mw / Mn can be obtained.

The amount of alkali metal carbonate used is preferably 90 to 110 mol%, and preferably 95 to 105 mol%, as an alkali metal, relative to the number of moles of the hydroxy group of the dihydric phenol (B). More preferably, it is 95 to 100 mol%, more preferably 95 mol% or more and less than 97 mol%. If no side reaction occurs, the greater the amount of alkali metal carbonate used, the faster the target polycondensation will proceed, and the degree of polymerization of the resulting aromatic polysulfone will increase, resulting in the aromatic polysulfone. Tends to increase the reduced viscosity, increase Mn, and decrease Mw / Mn. However, in fact, the larger the amount of alkali metal salt of carbonic acid used, the easier the side reaction similar to the above occurs, and this side reaction reduces the degree of polymerization of the resulting aromatic polysulfone. Therefore, it is necessary to adjust the amount of alkali metal carbonate used so that an aromatic polysulfone having a predetermined reduced viscosity, Mn and Mw / Mn is obtained in consideration of the degree of this side reaction.

In a typical aromatic polysulfone production method, the dihalogeno compound (A) and the dihydric phenol (B) were dissolved in an organic polar solvent as the first step, and the second step was obtained in the first step. The alkali metal salt of carbonic acid is added to the solution to polycondense the dihalogeno compound (A) and the dihydric phenol (B), and as a third stage, unreacted from the reaction mixture obtained in the second stage. An alkali polysulfone is obtained by removing the alkali metal salt of carbonic acid, the by-produced alkali halide, and the organic polar solvent.

The melting temperature in the first stage is preferably 40 to 180 ° C. The polycondensation temperature in the second stage is preferably 180 to 400 ° C., more preferably 300 to 400 ° C., and further preferably more than 300 ° C. and 360 ° C. or less. If no side reaction occurs, the higher the polycondensation temperature, the faster the target polycondensation proceeds, and the higher the degree of polymerization of the resulting aromatic polysulfone. As a result, the aromatic polysulfone tends to have a reduced viscosity, Mn increases, and Mw / Mn decreases. However, in fact, the higher the polycondensation temperature, the easier the side reaction similar to the above occurs, and this side reaction reduces the degree of polymerization of the aromatic polysulfone obtained. Therefore, in consideration of the degree of this side reaction, it is necessary to adjust the polycondensation temperature so as to obtain an aromatic polysulfone having a predetermined reduced viscosity, Mn and Mw / Mn.

In the second stage polycondensation, usually, the temperature is gradually raised while removing by-product water, and after reaching the reflux temperature of the organic polar solvent, further preferably 1 to 50 hours, more preferably 2 It is preferably carried out by keeping the temperature for 30 hours. If no side reaction occurs, the longer the polycondensation time, the more the target polycondensation proceeds, and the higher the degree of polymerization of the aromatic polysulfone obtained. As a result, the aromatic polysulfone tends to have a reduced viscosity, Mn increases, and Mw / Mn decreases. However, actually, the longer the polycondensation time, the more the side reaction similar to that described above proceeds, and this side reaction reduces the degree of polymerization of the resulting aromatic polysulfone. Therefore, in consideration of the degree of this side reaction, it is necessary to adjust the polycondensation time so that an aromatic polysulfone having a predetermined reduced viscosity, Mn and Mw / Mn can be obtained.

In the third stage, first, unreacted alkali metal salt of carbonic acid and by-produced alkali halide are removed from the reaction mixture obtained in the second stage by filtration, extraction, centrifugation, etc. A solution in which the group polysulfone is dissolved in an organic polar solvent is obtained. Subsequently, an aromatic polysulfone is obtained by removing the organic polar solvent from this solution. The removal of the organic polar solvent may be performed by directly distilling off the organic polar solvent from the solution, or the solution is mixed with a poor solvent for the aromatic polysulfone to precipitate the aromatic polysulfone, followed by filtration or You may carry out by isolate | separating by centrifugation etc.

Examples of the poor solvent for aromatic polysulfone include methanol, ethanol, 2-propanol, hexane, heptane, and water, and methanol is preferable because it can be easily removed.

When a relatively high melting point organic polar solvent is used as the polymerization solvent, unreacted alkali metal salt of carbonic acid and by-produced alkali halide, organic polarity are obtained from the reaction mixture obtained in the second step. Aromatic polysulfone may be obtained by extracting and removing impurities such as a solvent. Specifically, the reaction mixture may be cooled and solidified, then pulverized, and the resulting powder may be washed to extract and remove impurities to obtain aromatic polysulfone. In the washing, first, unreacted alkali metal salt of carbonic acid and by-produced alkali halide are extracted from the powder with water, the aromatic polysulfone is not dissolved, and the organic polar solvent is dissolved (uniformly). The organic polar solvent may be extracted and removed with the solvent to be mixed. In that case, the water used for extraction of the unreacted alkali metal salt of carbonic acid and the by-produced alkali halide is preferably warm water.
Here, the temperature of the hot water used for extraction is preferably 40 to 80 ° C.

The volume average particle size of the powder is preferably 200 to 2000 μm, more preferably 250 to 1500 μm, and further preferably 300 to 1000 μm from the viewpoint of extraction efficiency and workability during extraction. When the volume average particle diameter of the powder is equal to or more than the lower limit, solidification during extraction and clogging during filtration and drying after extraction are highly suppressed. Moreover, extraction efficiency becomes higher because the volume average particle diameter of the said powder is below the said upper limit.
In the present specification, the “volume average particle diameter” can be measured by a laser diffraction method.

Examples of the extraction solvent include, for example, a mixed solvent of acetone and methanol when diphenyl sulfone is used as a polymerization solvent. Here, the mixing ratio of acetone and methanol is usually determined from the viewpoint of extraction efficiency and stickiness of the aromatic polysulfone powder.

In another method for producing typical aromatic polysulfone, as a first step, dihydric phenol (B) and an alkali metal carbonate are reacted in an organic polar solvent to remove by-product water. Then, as the second stage, the dihalogeno compound (A) is added to the reaction mixture obtained in the first stage to perform polycondensation, and as the third stage, as in the case of the method described above, Unreacted alkali metal salt of carbonic acid, by-produced alkali halide and organic polar solvent are removed from the reaction mixture obtained in two steps to obtain aromatic polysulfone.

In this alternative method, azeotropic dehydration may be performed by adding an organic solvent azeotropic with water in order to remove by-product water in the first stage. Examples of the organic solvent azeotropic with water include benzene, chlorobenzene, toluene, methyl isobutyl ketone, hexane, cyclohexane and the like. The temperature for azeotropic dehydration is preferably 70 to 200 ° C.

In this alternative method, the reaction temperature in the second stage polycondensation is usually 180 to 400 ° C., preferably 300 to 400 ° C., more preferably more than 300 ° C. and 360 ° C. or less. In this alternative method, as in the case of the method described above, the polycondensation temperature is set so that an aromatic polysulfone having a predetermined reduced viscosity, Mn and Mw / Mn is obtained in consideration of the degree of side reaction. It is necessary to adjust the polycondensation time.

As described above, the aromatic polysulfone of the present invention has a ratio value (Mw / Mn) of the number average molecular weight (Mn) to the weight average molecular weight (Mw) of 1.91 or more, and the number average molecular weight (Mn) is By being 6000 or more and less than 14000, a high glass transition temperature can be expressed.
As for Mn and Mw / Mn of aromatic polysulfone, as described above, the ratio of the amount of dihalogeno compound (A) used during polymerization and the amount of dihydric phenol (B) used, the amount of alkali metal carbonate used, It can be adjusted by controlling the reaction conditions of the second stage polycondensation temperature and the second stage polymerization time. These reaction conditions are independently controlled for the purpose of adjusting Mn and Mw / Mn of the aromatic polysulfone, and can be arbitrarily combined.
In addition, the aromatic polysulfone obtained by the above-described method has a number average molecular weight (Mn) and a weight average molecular weight (Mw) ratio value (Mw / Mn) of 1.91 or more, and the number average molecular weight (Mn). Can be purified or adjusted by a known method so that the value is 6000 or more and less than 14,000.

Since the aromatic polysulfone of the present invention has a high glass transition temperature and excellent heat resistance, its function is sufficiently exhibited even under severe heat treatment conditions. The aromatic polysulfone of the present invention also has good adhesion to materials such as metal, glass and ceramic. Therefore, the aromatic polysulfone of the present invention is suitable as a coating material for members such as metal, glass or ceramic. For the coating of the member, for example, a resin composition (hereinafter, also referred to as a resin solution) containing an aromatic polysulfone and a resin other than this is prepared, and this is applied to a target member and dried. Thus, the resin coating film can be formed on the surface of the member. However, this is only an example, and the use of the aromatic polysulfone of the present invention is not limited thereto. The aromatic polysulfone of the present invention is suitable for use in fields such as automobiles and aircraft.

<Prepreg>
A second aspect of the present invention is a prepreg formed from the aromatic polysulfone according to the first aspect of the present invention, a liquid epoxy resin, a curing agent, and reinforcing fibers.

[Epoxy resin]
The epoxy resin is not particularly limited as long as it is a liquid epoxy resin, and for example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, and the like can be used as appropriate.
The term “liquid” as used herein means a liquid state at 0 to 40 ° C.

[Curing agent]
The curing agent is not particularly limited as long as it can react with the epoxy resin, but an amine curing agent is preferably used. Examples of the curing agent include tetramethylguanidine, imidazole or derivatives thereof, carboxylic acid hydrazides, tertiary amines, aromatic amines, aliphatic amines, dicyandiamide or derivatives thereof.

[Reinforcing fiber]
The reinforcing fiber is preferably at least one selected from the group consisting of carbon fiber, glass fiber, and aramid fiber from the viewpoint of strength, and more preferably carbon fiber. These reinforcing fibers may be woven fabric or non-woven fabric. Moreover, the use of the aromatic polysulfone resin of the present invention is not limited to this, and can also be used as a coating material for a member such as metal, glass or ceramic.

<Method for producing prepreg>
A third aspect of the present invention is a method for producing a prepreg, comprising the step of impregnating a reinforcing fiber into a mixture obtained by mixing the aromatic polysulfone according to the first aspect of the present invention, a liquid epoxy resin, and a curing agent. Is the method.
The method for producing the prepreg is not particularly limited, and a mixture prepared by dissolving the aromatic polysulfone of the first aspect of the present invention, the liquid epoxy resin, and the curing agent in a solvent such as methyl ethyl ketone and methanol is prepared. The mixture may be impregnated with reinforcing fibers. Examples of the solvent to be used include methyl ethyl ketone, methanol, dimethyl sulfoxide, N, N-dimethylformamide, N-methylpyrrolidone, dimethylacetamide and the like.
Examples of methods for impregnating the mixture with reinforcing fibers include a wet method and a hot melt method (also referred to as a dry method).
The wet method is a method of impregnating the aromatic fibers with aromatic polysulfone by immersing the reinforcing fibers in the mixture, then pulling up the reinforcing fibers and evaporating the solvent from the reinforcing fibers using an oven or the like.
The hot melt method is a method of impregnating a reinforcing fiber directly with the mixture whose viscosity has been reduced by heating, or a film in which the mixture is coated on a release paper or the like, and then from both sides or one side of the reinforcing fiber. In this method, the reinforcing fibers are impregnated with a resin by overlapping the films and heating and pressing.

In this way, after impregnating the reinforcing fiber with the epoxy resin and the aromatic polysulfone of the present embodiment, the prepreg is manufactured by, for example, heating to 120 to 140 ° C. and semi-curing the impregnated epoxy resin. be able to.
In this specification, “semi-cured” means a state in which the viscosity or hardness of the epoxy resin has increased until a certain shape can be maintained, and the viscosity or hardness has increased from the above state to a state in which the viscosity or hardness can be further increased. It refers to a state that can be increased.

Hereinafter, the present invention will be described in more detail with reference to specific examples. However, the present invention is not limited to the following examples.
In this example, evaluation of aromatic polysulfone was performed by measuring physical properties by the following methods.

<Measurement of Mn and Mw of aromatic polysulfone, calculation of Mw / Mn>
Gel permeation chromatography (GPC) analysis was performed under the following conditions, Mn and Mw were measured, and Mw / Mn was calculated. Both Mn and Mw were measured twice, and the average values thereof were determined as Mn and Mw, respectively, and the value of Mw / Mn was determined from Mn and Mw determined as average values.
(Measurement condition)
Sample: N, N-dimethylformamide solution of aromatic polysulfone with a concentration of 0.002 g / mL Sample injection volume: 100 μL
Column: Two “TSKgel GMHHR-H” (7.8 mmφ × 300 mm) manufactured by Tosoh Corporation are connected in series. Column temperature: 40 ° C.
Eluent: N, N-dimethylformamide Eluent flow rate: 0.8 mL / min Detector: Differential refractometer (RI) + Light scattering photometer (MALS)
Standard reagent: Polystyrene

<Measurement of glass transition temperature of aromatic polysulfone resin>
The glass transition temperature was calculated by a method according to JIS-K7121 using a differential scanning calorimeter (DSC-50 manufactured by Shimadzu Corporation). About 10 mg of the sample was weighed and raised to 340 ° C. at a heating rate of 10 ° C./min, then cooled to 40 ° C., and again raised to 340 ° C. at a heating rate of 10 ° C./min. From the DSC chart obtained by the second temperature increase, the glass transition temperature was calculated by a method according to JIS-K7121.

<Production and evaluation of aromatic polysulfone>
[Example 1]
In a polymerization tank equipped with a stirrer, a nitrogen introduction tube, a thermometer, and a condenser with a receiver at the tip, 300.3 g of bis (4-hydroxyphenyl) sulfone, 330.8 g of bis (4-chlorophenyl) sulfone, and As a polymerization solvent, 564.9 g of diphenylsulfone was charged, and the temperature was raised to 180 ° C. while nitrogen gas was circulated in the system. After adding 159.7 g of potassium carbonate to the obtained solution, the temperature was gradually raised to 305 ° C., and the mixture was further reacted at 305 ° C. for 3 hours. The obtained reaction solution was cooled to room temperature, solidified, finely pulverized, then washed several times with warm water and with a mixed solvent of acetone and methanol, and the powder impregnated with the solvent obtained by filtration at 150 ° C. Heat drying was performed to obtain aromatic polysulfone as a powder. Table 1 shows Mn, Mw, Mw / Mn and glass transition temperature of the obtained aromatic polysulfone.

[Comparative Example 1]
In a polymerization tank equipped with a stirrer, a nitrogen introduction tube, a thermometer, and a condenser with a receiver at the tip, 300.3 g of bis (4-hydroxyphenyl) sulfone, 331.8 g of bis (4-chlorophenyl) sulfone, and As a polymerization solvent, 564.9 g of diphenylsulfone was charged, and the temperature was raised to 180 ° C. while nitrogen gas was circulated in the system. After adding 160.5 g of potassium carbonate to the obtained solution, the temperature was gradually raised to 290 ° C., and the mixture was further reacted at 290 ° C. for 3 hours. The obtained reaction solution is cooled to room temperature, solidified, finely pulverized, then washed several times with warm water and with a mixed solvent of acetone and methanol, and a powder impregnated with the solvent obtained by decantation and filtration is obtained. Heating and drying at 150 ° C. gave an aromatic polysulfone as a powder. Table 1 shows Mn, Mw, Mw / Mn and glass transition temperature of the obtained aromatic polysulfone.

As is clear from Table 1, the aromatic polysulfone of Example 1 had a higher glass transition temperature than that of Comparative Example 1 and was excellent in heat resistance.

The present invention is extremely useful industrially because it can be used in the field of materials that require high heat resistance, such as coating materials for materials such as metals, glass, and ceramics.

Claims

A thermoplastic aromatic polysulfone obtained by polymerizing a dihalogeno compound (A) represented by the formula (A) and a dihydric phenol (B) represented by the formula (B),
An aromatic polysulfone having a Mw / Mn which is a value of a ratio of Mn which is a number average molecular weight and Mw which is a weight average molecular weight is 1.91 or more and a number average molecular weight (Mn) is 6000 or more and less than 14,000.

[In the formulas (A) and (B), X and X ′ each independently represent a halogen atom;
R 1 , R 2 , R 3 and R 4 each independently represent an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms;
n 1 , n 2 , n 3 and n 4 each independently represent an integer of 0 to 4;
When n 1 , n 2 , n 3 or n 4 is an integer of 2 to 4, a plurality of R 1 , R 2 , R 3 or R 4 may be the same or different from each other. ]
The aromatic polysulfone according to claim 1, wherein in the formula (A), X and X 'are chlorine atoms.
The aromatic polysulfone according to claim 1 or 2, wherein in the formula (A) or the formula (B), n 1 , n 2 , n 3 and n 4 are 0.
A prepreg formed from the aromatic polysulfone according to any one of claims 1 to 3, a liquid epoxy resin, a curing agent, and a reinforcing fiber.
A method for producing a prepreg, comprising a step of impregnating a reinforcing fiber into a mixture obtained by mixing the aromatic polysulfone according to any one of claims 1 to 3, a liquid epoxy resin, and a curing agent.