JP4660183B2 - Method for producing polyarylate - Google Patents

Description

The present invention, little discoloration, to a method for producing a high purity Poriarire preparative high productivity economically.

Polyarylate composed of dihydric phenol and aromatic dicarboxylic acid is 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.
In order to further improve 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 of the polyarylate, and the polymerization catalyst remaining in the polyarylate has the electrical properties of the polyarylate. It was sometimes reduced.

  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, diphenoquinone having an alkyl group introduced therein is highly colored, and polyarylate containing it is remarkably colored. Therefore, application to applications requiring transparency has been limited. In addition, diphenoquinone compounds tend to lower the insulating properties together with dihydric phenols, and polyarylates containing these have limited applications in the electric and electronic fields.

  In order to solve this problem, in Patent Document 1, the polyarylate is heated under a reduced pressure at a temperature from 180 ° C. to the glass transition temperature of the polyarylate to remove the colored substance. Methods have been proposed for producing 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 and a decrease in electrical characteristics due to this. There was a problem.

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, since this method uses a large amount of organic solvent relative to polyarylate, special equipment is required, which is not economical and is a problem of environmental protection, and the total cost including recycling of organic solvent. The rise of was remarkable.
JP 2002-293944 A

An object of the present invention is to provide is to residual catalyst or coloring substances less, to provide an economical manufacturing how the high excellent purity transparency Poriarire bets.

As a result of intensive studies to solve the above-mentioned problems, the present inventor carried out a polymerization reaction using a specific amount of a quaternary ammonium salt having a specific structure as a polymerization catalyst, and before the polymerization reaction stopped, The inventors have found that by adding a carboxylic acid halide, the residual monomer and its oxidized form can be easily removed to produce a polyarylate having a high molecular weight, and the present invention has been completed.
That is, the gist of the present invention is as follows.
(1) In the step of interfacial polymerization reaction between a divalent aromatic carboxylic acid halide and a divalent phenol, a quaternary ammonium salt represented by the following formula (1) is used as a catalyst in an amount of 5 to 5 with respect to the divalent phenol. A method for producing polyarylate, comprising using 20 mol% and adding 3 to 10 mol% of a monovalent carboxylic acid halide with respect to a dihydric phenol before stopping the interfacial polymerization reaction.

(In the formula, Y represents an ethyl group or a benzyl group, and X represents Cl, Br, I, OH, or HSO4.)

  According to the present invention, it is possible to produce a polyarylate having a high molecular weight and a remarkably small amount of catalyst, excellent mechanical properties, and at the same time excellent electrical properties, particularly insulating properties, with good productivity and economically. it can. 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 insulating materials such as electric devices, motors, generators, interphase insulating films, dielectric films such as transformers and capacitors, liquid crystal display plates and various substrates, for example, as films, 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.

The present invention is described in detail below.
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 point transfer (Tg) of polyarylate cannot be 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 needs to be a quaternary ammonium salt represented by the above formula (1) and having 3 or 4 ethyl groups.

  Specific examples of the polymerization catalyst include triethylbenzylammonium chloride, triethylbenzylammonium bromide, triethylbenzylammonium hydroxide, triethylbenzylammonium hydrogensulfate, tetraethylammonium chloride, tetraethylammonium bromide, tetraethylammonium hydroxide, tetraethylammonium hydrogensulfate, etc. Is mentioned. Of these, triethylbenzylammonium chloride is preferred.

The polymerization catalyst needs to be added in an amount of 5 to 20 mol% with respect to the dihydric phenol. High molecular weight polyarylate can be synthesized by adding a polymerization catalyst in an amount of 5 to 20 mol% based on the dihydric phenol. Usually, in the interfacial polymerization method, it is common knowledge that the addition amount of the polymerization catalyst is 1 mol% or less with respect to the dihydric phenol, and even 1 mol% in the usual concept of “catalyst” can be said to be an adequate amount. .
By the way, in order to obtain a high molecular weight polyarylate as in the present invention, it is necessary to use a polymerization catalyst having higher activity, and for this purpose, one having three butyl groups such as tributylbenzylammonium chloride is preferable. However, such a catalyst has a higher lipophilicity than the ethyl group, so that the reactivity can be increased, but the tendency to remain on the organic phase side is strong, and it is easily washed away after completion of the reaction. It becomes difficult. Therefore, in the present invention, this common sense is overcome, and conversely, by adding a larger amount of the catalyst represented by the formula (1), which is relatively low in lipophilicity and easy to wash, the reactivity is increased and washing is performed. It is possible to maintain sex.
As described above, the polymerization catalyst needs to be added in an amount of 5 to 20 mol% with respect to the dihydric phenol. When the addition amount is less than 5 mol%, the polyallylate having a low molecular weight and the characteristics of the present invention is produced. In contrast, even if the amount is more than 20 mol%, a hydrolysis reaction of an ester, which is a side reaction, occurs and the molecular weight decreases. The optimum addition amount of the polymerization catalyst is in the range of 7 to 15 mol%.

  By using the polymerization catalyst, 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.

  Further, a monofunctional compound, specifically, phenol, cresol, p-tert-butylphenol or the like may be added to the aqueous phase as a molecular weight regulator.

  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, To chlorinated solvents such as 2,2-tetrachloroethane, 1,1,1-trichloroethane, o-, m-, p-dichlorobenzene, aromatic hydrocarbons such as toluene, benzene, xylene, or tetrahydrofuran, A phase in which a valent 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 performing an interfacial polycondensation reaction with stirring at a temperature of 25 ° C. or lower for 1 to 5 hours.

  In the present invention, before the polymerization reaction is completed, in order to remove the remaining dihydric phenol and diphenoquinone, it is necessary to add a monovalent carboxylic acid halide that reacts therewith. The carboxylic acid halide used must be monovalent. When divalent or higher carboxylic acid halides are used, they can be removed by reacting with the remaining dihydric phenol or diphenoquinone, but the end-group of the dimer produced after the reaction is carboxylic acid. For this reason, the carboxyl value of the resin as a whole is greatly increased, and the final electrical characteristics are remarkably deteriorated.

  The most suitable time for adding the monovalent carboxylic acid halide is before the stirring of the polymerization is stopped. When added in the initial stage of polymerization, the molar balance of the polymerization is greatly lost, and the molecular weight of polyarylate does not increase. Even if it is added in the middle of the polymerization, the molar balance is greatly lost, a depolymerization reaction occurs, and the molecular weight decreases. Furthermore, when the reaction system is neutralized after completion of the polymerization and then added, there is no effect because bisphenols are precipitated. Therefore, it is appropriate that the monovalent carboxylic acid halide is added before the polymerization is stopped. As an indication of the time to be added, it is appropriate about 5 to 10 minutes before the polymerization is stopped, but since the effect varies depending on the difference in the size of the apparatus and the stirring ability, it may be an optimal time before and after this time. . Further, the addition amount of the monovalent carboxylic acid halide needs to be 3 to 10 mol% with respect to the divalent phenol. If it is less than 3 mol%, the effect is not sufficiently exhibited. Moreover, when it exceeds 10 mol%, monovalent | monohydric carboxylic acids will react and produce | generate an acid anhydride, and this will be contained in resin. When the resin is used, the acid anhydride is easily decomposed by heat or the like, and the carboxylic acid is regenerated, thereby increasing the carboxyl value of the resin and lowering the electrical characteristics.

  Specific monovalent carboxylic acid halides include fats such as acetyl chloride, propionyl chloride, n-butyryl chloride, n-valeryl chloride, stearoyl chloride, benzoyl chloride, p-nitrobenzoyl chloride, and 3,5-dinitrobenzoyl chloride. And aromatic and aromatic carboxylic acid halides. Of these, benzoyl chloride is preferred.

  As described above, the content of the quinone oxide in the polyarylate of the present invention can be reduced to 30 ppm or less by adding a monovalent carboxylic acid halide before the polymerization is stopped. If the content of the quinone oxide exceeds 30 ppm, the degree of coloring increases, and the electrical characteristics are also affected, which is not preferable.

  Moreover, the range of the carboxyl value of the polyarylate of this invention can be 30 mol / t or less by adding a specific amount of monovalent carboxylic acid halide. When the carboxyl value exceeds 30 mol / t, the electrical properties are remarkably lowered when the coating film is formed.

  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 is prepared by dissolving a coating solution dissolved in a solvent, 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 solution 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 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 weight or more. The coating solution may contain various additives as necessary, and after coating on the base material, the solvent is removed to form a film, which can be used as a film or as a film by peeling it off. it can.

  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 chromatograph (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 a biphenol, bisphenols 2,2-bis (3-methyl-4-hydroxyphenyl) propane (hereinafter abbreviated as bisphenol C) 23.43 g (0.091 mol), and p-tert-butylphenol (hereinafter abbreviated as PTBP) 0 as a molecular weight regulator .46 g (0.003 mol), sodium hydroxide 17.31 g (0.433 mol), and triethylbenzylammonium chloride (hereinafter abbreviated as TEBAC) 4.16 g (0.018 mol, total dihydric phenol as a polymerization catalyst) 10 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 previously prepared aqueous phase under strong stirring, and an interfacial polycondensation reaction was performed at 15 ° C. for 2 hours. Benzoyl chloride 1.28 g (0.009 mol) was added 10 minutes before the polymerization was stopped (stopping stirring). Then, after stirring was stopped, the aqueous phase and the organic phase were decanted and separated. Acetic acid was added to the organic phase from which the aqueous phase (alkaline water) had been removed while adding equal amount of ion-exchanged water and stirring until the pH became neutral. Furthermore, after stirring for 20 minutes, it was allowed to stand for 20 minutes, and then decanted to remove the aqueous phase and replace it with new ion-exchanged water. The washing operation was repeated 5 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 the dihydric phenol, the type and addition amount of the polymerization catalyst, and the addition amount of the monovalent carboxylic acid halide 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 (1)

In the step of interfacial polymerization reaction between a divalent aromatic carboxylic acid halide and a divalent phenol, a quaternary ammonium salt represented by the following formula (1) is used as a catalyst in an amount of 5 to 20 mol% based on the divalent phenol. A method for producing polyarylate, which comprises using 3 to 10 mol% of a monovalent carboxylic acid halide with respect to a divalent phenol before stopping the interfacial polymerization reaction.
(In the formula, Y represents an ethyl group or a benzyl group, and X represents Cl, Br, I, OH, or HSO4.)