JP2006328147A - Polyarylate and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyarylate scarcely containing a catalyst remaining therein or coloring matter, excellent in transparency, and having high purity, and to provide a method for easily producing the same. <P>SOLUTION: This method for producing the polyarylate comprises using a quaternary ammonium salt of formula (1) (Y is butyl or benzyl; and X is Cl, Br, I, OH or HSO<SB>4</SB>) as a catalyst in an amount of 0.3-1.5 mol% based on a dihydric phenol and subjecting an aromatic dicarboxylic acid halide and the dihydric phenol to interfacial polycondensation reaction. Further, a process for adding water to an organic phase after the polycondensation reaction and washing the organic phase in the method comprises (A) a process for stirring the organic phase and a water phase, while adding an acid thereto until a pH of the water phase reaches to 4 or less, and then removing the water phase and (B) a process for stirring the organic phase and the water phase and then removing the water phase, wherein the process (A) is conducted, then the process (B) is repeatedly conducted until the pH of the water phase reaches to 5 or more, further the process (A) is conducted, and furthermore the process (B) is repeatedly conducted until the pH of the water phase reaches to 5 or more. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a polyarylate having low coloration and high purity, and a method for producing it economically with high productivity.

Polyarylate composed of dihydric phenol and aromatic dicarboxylic acid is widely used mainly in the field of electric and electronic materials due to its high heat resistance and low heat shrinkage. Various methods for polymerizing polyarylate are known, and an interfacial polymerization method that yields a polymer having a high molecular weight, little coloration, and high purity is considered optimal.
As a measure for further improving the heat resistance of polyarylate, polyarylate having a biphenyl structure introduced into its skeleton has been developed. However, when a polyarylate having a biphenyl structure is polymerized, the polymerization catalyst may remain in the polyarylate due to the structure, and the polymerization catalyst remaining in the polyarylate deteriorates the electrical properties of the polyarylate. That was a problem.

  On the other hand, in order to introduce a biphenyl structure into polyarylate, biphenols are used as a monomer of polyarylate. These biphenols are easily oxidized, and when they are polymerized with an aromatic dicarboxylic acid by an interfacial polymerization method, a part of the biphenols may be converted to a diphenoquinone. In particular, a diphenoquinone compound having an alkyl group introduced as a substituent has a high degree of coloring, and the polyarylate containing it is naturally markedly colored, and its application to applications requiring transparency is limited. It was done. In addition, diphenoquinone bodies tend to lower the insulating properties together with dihydric phenols, and polyarylates containing these have also been limited to applications in the electric and electronic fields.

  In order to solve these problems, in Patent Document 1, the polyarylate is removed by heating at a temperature from 180 ° C. to the glass transition point of the polyarylate under reduced pressure, thereby removing the coloring and impurities. There has been proposed a method for producing a low polyarylate. However, in this method, the heat treatment at a high temperature of 180 ° C. or higher causes the ester bond of the main chain to be cleaved, resulting in a decrease in molecular weight, resulting in an increase in end groups, thereby reducing electrical properties, It was not an ideal solution.

There is also a method of removing these by washing the polyarylate after polymerization using an organic solvent that dissolves a diphenoquinone or dihydric phenol. However, even with this method, a large amount of organic solvent is used for polyarylate, so special equipment is required, which is not economical, environmental protection, and the total cost including recycling of organic solvent. The rise of was remarkable.
JP 2002-293944 A

  The problem to be solved by the present invention is to provide a highly pure polyarylate excellent in transparency, having few residual catalysts and coloring substances, and an economical production method thereof.

As a result of intensive studies to solve the above-mentioned problems, the present inventor conducted a polymerization reaction using a specific amount of a quaternary ammonium salt having a specific structure as a polymerization catalyst, and in the water washing step after polymerization, The present invention was completed by finding that the amount of catalyst remaining could be reduced by once washing with water under acidic conditions of pH 4 or less and changing the aqueous phase having a pH of 5 or more back to acidic conditions of pH 4 or less.
That is, the gist of the present invention is as follows.
(1) A quaternary ammonium salt represented by the following formula (1) is used as a catalyst in an amount of 0.3 to 1.5 mol% with respect to a divalent phenol, and a divalent aromatic carboxylic acid halide and divalent are used. A method for producing polyarylate by interfacial polycondensation reaction with phenol, the step of adding water to the organic phase after the polymerization reaction to wash the organic phase,
(A) The step of removing the aqueous phase after stirring the organic phase and the aqueous phase while adding acid until the pH of the aqueous phase is 4 or less;
(B) a step of removing the aqueous phase after stirring the organic phase and the aqueous phase;
The polyarylate is characterized in that after step A, the step B is repeated until the pH of the aqueous phase becomes 5 or more, and then after step A, the step B is repeated until the pH of the aqueous phase becomes 5 or more. Manufacturing method.
(In the formula, Y represents a butyl group or a benzyl group, and X represents a halogen atom of Cl, Br, or I, OH, or HSO _4. )
(2) Polyarylate represented by the following formula (2), having an inherent viscosity (ηinh) of 0.85 to 1.80 dl / g, a carboxyl value of 30 mol / t or less, and a glass transition point (Tg ) Is 195 ° C. or higher, the content of the quinone oxide of dihydric phenol is 30 ppm or less, and the content of the quaternary ammonium salt represented by the following formula (1) is 20 ppm or less. Polyarylate.
(In the formula, Y represents a butyl group or a benzyl group, and X represents a halogen atom of Cl, Br, or I, OH, or HSO _4. )
(R1 to R8 in the formula represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, and m / n is 80/20 to 20/80.)

  According to the present invention, a polyarylate having a high molecular weight and a remarkably small amount of remaining catalyst, excellent mechanical properties, and at the same time excellent electrical properties, particularly insulating properties, can be produced with good productivity and economically. . Moreover, since the polyarylate of the present invention is easily dissolved in a general-purpose solvent, it can be dissolved in a solvent to prepare a coating solution, and can be easily formed into a film or a surface film. Therefore, the polyarylate of the present invention is applied to, for example, a film, an insulating material such as an electric device, a motor, a generator, an interlayer insulating film, a dielectric film such as a transformer or a capacitor, a liquid crystal display plate or various substrates, In addition, the surface coating can be applied to a coating of an electric wire, an insulating coating material, and the like, and its industrial utility value is extremely high.

Hereinafter, the present invention will be described in detail.
First, the polyarylate of the present invention will be described. Polyarylate is a polyester composed of a dihydric phenol residue and an aromatic divalent carboxylic acid residue. In the present invention, it is synthesized by interfacial polymerization. That is, it is carried out by mixing dihydric phenol (aqueous phase) dissolved in an alkaline aqueous solution and divalent carboxylic acid halide (organic phase) dissolved in an organic solvent that does not dissolve in water (WM EARECKSON). J. Poly.Sci.XL399 1959, Japanese Patent Publication No. 40-1959). The interfacial polymerization method is faster in reaction than the solution polymerization method, and therefore, hydrolysis of the acid halide can be minimized, which is advantageous when obtaining a high molecular weight polyarylate as in the present invention. It is a synthesis method.

  Examples of the divalent aromatic carboxylic acid halide that can be used in the present invention include terephthalic acid halide, isophthalic acid halide, phthalic acid halide, or a mixture in which an aromatic group is substituted with an alkyl group or a halogen group. Preferably, a mixture of 10-90 mol% terephthalic acid halide and 90-10 mol% isophthalic acid halide is used, and industrially advantageous is an equal mixture of both.

  The dihydric phenol used in the present invention is composed of bisphenols and biphenols. As specific examples of the biphenols, 3,3 ′, 5,5′-tetramethyl-4,4′-dihydroxybiphenyl is preferable from the viewpoint of solvent solubility of the produced polyarylate.

  As bisphenols, bisphenols having an isopropylidene group at the center of the skeleton are used. Specific examples include 2,2-bis (4-hydroxyphenyl) propane (bisphenol A), 2,2-bis (3-methyl-4-hydroxyphenyl) propane (bisphenol C), and the like. 2,2-bis (3-methyl-4-hydroxyphenyl) propane (bisphenol C) is preferred in that the resulting polyarylate is excellent in solvent solubility.

  The copolymerization ratio (m / n) shown in the formula (2) needs to be in the range of 80/20 to 20/80, and preferably 70/30 to 30/70. When m is less than 20%, since the solvent solubility of the produced polyarylate is lowered, the molecular weight does not increase. On the other hand, when m exceeds 80%, the effect of copolymerizing the biphenyl component is insufficient, the glass transition point (Tg) of polyarylate cannot be made 195 ° C. or higher, high heat resistance and low heat shrinkage. Polyarylate having a rate cannot be obtained.

  A method for synthesizing polyarylate by interfacial polymerization will be described in detail. First, an aqueous alkali solution of a dihydric phenol is prepared as an aqueous phase, and then a phase to which a polymerization catalyst and a molecular weight modifier are added is used. Examples of the alkali that can be used here include sodium hydroxide and potassium hydroxide.

  In the present invention, the polymerization catalyst is required to be a quaternary ammonium salt represented by the formula (1) and having 3 or 4 butyl groups.

  Specific examples of the polymerization catalyst include tri-n-butylbenzylammonium chloride, tri-n-butylbenzylammonium bromide, tri-n-butylbenzylammonium hydroxide, tri-n-butylbenzylammonium hydrogen sulfate, tetra-n-butylammonium chloride, Examples include tetra n-butylammonium bromide, tetra n-butylammonium hydroxide, tetra n-butylammonium hydrogen sulfate. Of these, tri-n-butylbenzylammonium chloride is preferred.

  The polymerization catalyst needs to be added in an amount of 0.3 to 1.5 mol% with respect to the dihydric phenol. If the addition amount is less than 0.3 mol%, it is impossible to produce a polyarylate having a low molecular weight and the characteristics of the present invention. Decomposition occurs and the molecular weight decreases. The addition amount of the polymerization catalyst is preferably in the range of 0.5 to 1.2 mol%, more preferably 0.5 to 1.0 mol%.

  In addition, a monofunctional compound, specifically phenol, cresol, p-tert-butylphenol, or the like may be added to the aqueous phase as a molecular weight modifier during polymerization.

  Next, as an organic phase, a solvent which is incompatible with water and dissolves polyarylate, specifically, methylene chloride, 1,2-dichloroethane, chloroform, carbon tetrachloride, chlorobenzene, 1,1 , 2,2-tetrachloroethane, 1,1,1-trichloroethane, chlorinated solvents such as o-, m-, p-dichlorobenzene, aromatic hydrocarbons such as toluene, benzene, xylene, etc. A phase in which an aromatic carboxylic acid halide is dissolved is used. A high molecular weight polyarylate can be obtained by mixing this organic phase solution with the aforementioned aqueous phase solution and conducting an interfacial polycondensation reaction with stirring at a temperature of 25 ° C. or lower for 1 to 5 hours.

In the present invention, the step of washing the organic phase by adding water to the organic phase after the polymerization reaction,
(A) The step of removing the aqueous phase after stirring the organic phase and the aqueous phase while adding acid until the pH of the aqueous phase is 4 or less;
(B) a step of removing the aqueous phase after stirring the organic phase and the aqueous phase;
It is necessary to repeat the B process until the pH of the aqueous phase becomes 5 or more after the A process, and then repeat the B process until the pH of the aqueous phase becomes 5 or more after the A process.
That is, after separating the aqueous phase after the polymerization reaction, water is added to the organic phase and stirred while adjusting the pH of the aqueous phase to 4 or less. Thereafter, the organic phase is washed with water, and when the pH of the aqueous phase becomes 5 or more, the pH is adjusted to 4 or less in the same manner, and the water phase is washed until the pH of the aqueous phase becomes 5 or more.

In the present invention, the polymerization catalyst having at least three butyl groups used for the production of polyarylate has higher lipophilicity than the commonly used trimethylbenzylammonium chloride and triethylbenzylammonium chloride, and therefore has a catalytic activity. Therefore, a high molecular weight polyarylate can be obtained with a small addition amount, which is an optimum polymerization catalyst. Further, when this catalyst is used, due to its high activity, the residual monomer which becomes a problem when a normal catalyst is used becomes very small. For this reason, there is no significant coloring phenomenon due to the diphenoquinone produced when biphenols such as the present invention are used, and it is not necessary to perform a special heat treatment step or organic solvent washing step on the produced polymer. This is a great feature.
However, the catalyst used in the present invention tends to remain in the polymer solution because of its high lipophilicity. In particular, in the production of polyarylate having a biphenol structure, even if a normal water washing step is performed, the remaining amount is large, and there is a problem in application to the electric and electronic fields. However, the catalyst can be efficiently removed by performing the water washing step.

The reason for the effect of the present invention can be inferred as follows. That is, when the stirring is stopped after the polymerization of polyarylate is completed, the aqueous phase (alkaline water) and the organic phase (polymer solution) are usually phase-separated with a clear boundary. When only the aqueous phase is removed and neutralized with acid after adding pure water, the boundary between the aqueous phase and the organic phase becomes unclear at the time of pH = 5 to 7, and an intermediate phase (hereinafter referred to as intermediate phase) Is called a phase). When an acid is further added to lower the pH to 4 or less, the intermediate phase disappears and the boundary between the aqueous phase and the organic phase becomes clear again. Normally, in the neutralization step, the polymerization catalyst and ionic substances are removed by ending with pH = 5 to 7 and then washing with water. However, when this intermediate phase is separated and removed, Since it also contains a phase, there are problems such as a decrease in yield and a new intermediate phase.
This intermediate phase contains a polymerization catalyst at a higher concentration than the normal polymer solution due to the nature of the surfactant of the polymerization catalyst, so washing with water in the state where the intermediate phase is formed is very inefficient. It is. It is effective to adjust the pH to 4 or less to eliminate this intermediate phase and wash it. However, by repeating washing, the pH changes to 5 or more and the washing efficiency is lowered.
However, the polymerization catalyst was efficiently removed by eliminating the intermediate phase by adjusting the pH of the aqueous phase to 4 or less again and washing. It should be noted that the efficiency of washing with water is not improved by maintaining the pH at 4 or less from the beginning of the washing, but the polymerization catalyst can be prepared by adjusting the pH of 5 or more to produce an intermediate phase. Efficient redistribution to the water phase is thought to contribute to improving the cleaning efficiency.

  Examples of the acid used for adjusting the pH of the aqueous phase to 4 or less include acetic acid, hydrochloric acid, sulfuric acid, phosphoric acid, nitric acid, and the like. If the aqueous phase can be made acidic, the effects of the present invention can be realized, so that it is particularly limited. It is not something. Preferably, acetic acid is less affected by polymer degradation and the like, and the degree of corrosion of equipment and the like is low.

  By performing the washing method, the amount of the polymerization catalyst remaining in the polyarylate can be reduced to 20 ppm or less. Regardless of the type of polymerization catalyst, if the catalyst content exceeds 20 ppm, the electrical characteristics may be lowered, which may be a problem.

  The inherent viscosity (ηinh) of the polyarylate of the present invention is 0.85 to 1.80 dl / g, optimally 0.95 to 1.50 dl / g. When the inherent viscosity is less than 0.85 dl / g, when the polyarylate has insufficient mechanical properties, or when a coating solution dissolved in a solvent is prepared to form a film, the solution viscosity of the coating solution is Since it may be too low to be applied, it is not preferable. On the other hand, even if it exceeds 1.80 dl / g, the effect is not only saturated, but on the contrary, spinnability may occur during coating, or the viscosity of the coating liquid may increase and handling may become difficult. It is not preferable. The inherent viscosity (molecular weight) can be controlled by adding the polymerization catalyst and the molecular weight modifier. Specifically, high molecular weight can be achieved with an appropriate addition amount of the polymerization catalyst, and fine adjustment can be performed with a molecular weight adjusting agent.

  Since the polyarylate of the present invention is polymerized using a highly active polymerization catalyst, the amount of residual monomer is small. Therefore, it is not necessary to remove this by high-temperature treatment, and the main chain of polyarylate is not cleaved by heat, so that the carboxyl value can be 30 mol / t or less. When the carboxyl value exceeds 30 mol / t, the electrical properties are remarkably lowered when the coating film is formed.

  Moreover, the polyarylate of this invention can make the glass transition point (Tg) 195 degreeC or more by adjusting the ratio (m / n) of copolymerization to a specific range. When the glass transition point (Tg) is lower than 195 ° C., there is a problem in terms of heat resistance.

  Since the polyarylate of the present invention is polymerized using a highly active polymerization catalyst, the amount of residual monomer is reduced, so the content of the divalent phenol quinone oxide remaining in the polyarylate is 30 ppm or less. be able to. If the content of the quinone oxide of dihydric phenol exceeds 30 ppm, the degree of coloring increases, which is a problem, and it also affects the electrical characteristics, which is not preferable.

  Since the polyarylate of the present invention has good solubility in general-purpose solvents, it can be easily dissolved in a solvent to prepare a coating solution and can be used as a film-forming resin. Specific examples of such solvents include methylene chloride, 1,2-dichloroethane, chloroform, carbon tetrachloride, chlorobenzene, 1,1,2,2-tetrachloroethane, 1,1,1-trichloroethane, o-, m. -, Chlorinated solvents such as p-dichlorobenzene, aromatic hydrocarbons such as toluene, benzene and xylene, or tetrahydrofuran. When the coating liquid is used, the polyarylate is preferably completely dissolved in a solvent in which one kind or two or more kinds are appropriately selected so that the concentration is preferably 10% by mass or more. The coating solution contains various additives as necessary, and after coating on the substrate, the solvent is removed to form a film, and the film is coated or peeled off and used as a film. Can do.

  The polyarylate of the present invention is suitably used as a binder resin or a resin for a film. As a coating liquid as described above, the casting liquid, the melt extrusion method or the calendering method can be used to improve wear resistance and electrical properties. Excellent coatings and films can be produced, and can be applied particularly to the field of electronic materials.

  Next, the present invention will be specifically described by way of examples and comparative examples. However, the present invention is not limited to these examples, and various modifications and applications are possible without departing from the scope of the present invention. It is. In addition, the evaluation method was performed by the following method.

1) Inherent viscosity (ηinh)
1,1,2,2-Tetrachloroethane was used as a measurement solvent, and measurement was performed under the conditions of a concentration of 1 g / dl and a temperature of 25 ° C.
2) Carboxyl value After 0.3 g of a sample was dissolved in 20 ml of methylene chloride in an Erlenmeyer flask, an indicator (phenol red) was added, and the solution was determined with a 0.1 N KOH solution.
3) Glass transition temperature (Tg)
It calculated | required with the temperature increase rate of 20 degree-C / min using the differential thermal analyzer (The Perkin-Elmer company make, DSC-7 type | mold).
4) Content of quinone oxide The sample was subjected to Soxhlet extraction with acetonitrile and then subjected to HPLC measurement under the following conditions on the liquid filtered through a disk filter (pore diameter 0.45 μm).
(HPLC measurement conditions)
<Apparatus> HP1100 HPLC system manufactured by Hewlett Packard
<Column> Wakopak Wakosil 5C18-200T 4.6 mm × 150 mm (40 ° C.)
<Detector> UV 210nm
<Injection amount> 10 μm
<Eluent> MeCN / H ₂ 0 = 40/60 (Flow rate) 1.0 ml / min
5) Polymerization catalyst content After dissolving 0.5 g of a sample in 10 ml of chloroform, 40 ml of methanol was added to remove the reprecipitated resin. A fixed amount of diphenyl was added as an internal standard to the methanol solution containing the residual catalyst extracted in this manner, and this was analyzed with a gas chromatogram apparatus (HP-5890 series II manufactured by Hewlett Packard) to quantify the amount of residual catalyst. .

Example 1
In a reaction vessel equipped with a stirrer, 3,3 ′, 5,5′-tetramethyl-4,4′-dihydroxybiphenyl (hereinafter abbreviated as TMBP) 22.15 g (0.091 mol) as biphenols, bisphenols 2,2-bis (3-methyl-4-hydroxyphenyl) propane (bisphenol C) 23.43 g (0.091 mol) as a molecular weight regulator p-tert-butylphenol (hereinafter abbreviated as PTBP) 0.46 g ( 0.003 mol), 17.31 g (0.433 mol) of sodium hydroxide, and 0.39 g (0.001274 mol, total divalent phenol) of tri-n-butylbenzylammonium chloride (hereinafter abbreviated as TBBAC) as a polymerization catalyst. 0.7 mol%) was dissolved in 1223 ml of water (aqueous phase).
Separately, 37.42 g (0.184 mol) of a terephthalic acid chloride / isophthalic acid chloride = 1/1 mixture (hereinafter abbreviated as MPC) was dissolved in 715 ml of methylene chloride (organic phase). This organic phase was added to the aqueous phase prepared previously with vigorous stirring, and an interfacial polycondensation reaction was performed at 15 ° C. for 2 hours. After the polymerization was stopped, the aqueous phase and the organic phase were decanted and separated. Acetic acid was added to pH 4 while adding an equal amount of ion-exchanged water to the organic phase from which the aqueous phase (alkaline water) had been extracted and stirring. Furthermore, after stirring for 20 minutes, it was allowed to stand for 20 minutes, and then the operation of decanting and removing the aqueous phase and replacing it with new ion-exchanged water was repeated three times.
After confirming that the pH of the aqueous phase was 5 or more, acetic acid was added again until the pH reached 4. Thereafter, the operation of removing the aqueous phase and replacing it with new ion-exchanged water was repeated three times.
The polyarylate solution, which is the organic phase after washing, was poured into 50 ° C. warm water contained in a container equipped with a homomixer to evaporate methylene chloride to obtain a powdered polyarylate. After dehydrating the powdery polyarylate, the water-containing powdery polyarylate containing a small amount of water was dried under reduced pressure at 120 ° C. for 24 hours using a vacuum dryer to obtain a polyarylate resin.

Examples 2-10, Comparative Examples 1-10
A polyarylate resin was produced in the same manner as in Example 1 except that the composition of dihydric phenol, the type and amount of polymerization catalyst, and the type of acid added during washing were changed.

  It was shown in Table 1 together with the result of having evaluated the characteristic of the polyarylate obtained by the Example and the comparative example.

Claims (2)

As a catalyst, a quaternary ammonium salt represented by the following formula (1) is used in an amount of 0.3 to 1.5 mol% based on a dihydric phenol, and a divalent aromatic carboxylic acid halide and a dihydric phenol are used. A method of producing polyarylate by interfacial polycondensation reaction, the step of adding water to the organic phase after the polymerization reaction to wash the organic phase,
(A) The step of removing the aqueous phase after stirring the organic phase and the aqueous phase while adding acid until the pH of the aqueous phase is 4 or less;
(B) a step of removing the aqueous phase after stirring the organic phase and the aqueous phase;
The polyarylate is characterized in that after step A, the step B is repeated until the pH of the aqueous phase becomes 5 or more, and then after step A, the step B is repeated until the pH of the aqueous phase becomes 5 or more. Manufacturing method.
(In the formula, Y represents a butyl group or a benzyl group, and X represents a halogen atom of Cl, Br, or I, OH, or HSO _4. ) It is a polyarylate represented by the following formula (2), has an inherent viscosity (ηinh) of 0.85 to 1.80 dl / g, a carboxyl number of 30 mol / t or less, and a glass transition point (Tg) of 195. A polyarylate characterized by having a quinone oxide content of dihydric phenol of 30 ppm or less, and a quaternary ammonium salt content of the following formula (1) of 20 ppm or less. .
(In the formula, Y represents a butyl group or a benzyl group, and X represents a halogen atom of Cl, Br, or I, OH, or HSO _4. )
(R1 to R8 in the formula represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, and m / n is 80/20 to 20/80.)