JP2008214541A - Polyarylate and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high purity polyarylate being little in the content of remaining colored substances and excellent in transparency and provide its economical manufacturing method. <P>SOLUTION: The manufacturing method of the polyarylate is characterized in that, in the manufacturing process of the polyarylate of formula (1) that is produced by the interfacial polymerization reaction of a divalent aromatic carboxylic acid halide and a divalent phenol containing a biphenyl structure and a bisphenol structure, 20-80 wt.% of an antioxidant is added to the whole divalent phenol (in the formula, R1-R8 each indicate a hydrogen atom or a 1-8C alkyl group and m/n is a value of 80/20-20/80). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for producing a polyarylate, and more particularly to a method for producing a polyarylate having little coloration and high purity.

  Polyarylate is used mainly in the field of electrical and electronic materials due to its high heat resistance and low thermal 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. In order to introduce a biphenyl structure, biphenols are used as monomers of polyarylate. However, these biphenols are easily oxidized, and when they are reacted with an aromatic dicarboxylic acid by an interfacial polymerization method, a part thereof may be converted into 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, a polyarylate is removed by heating at a temperature from 180 ° C. to the glass transition temperature of the polyarylate under reduced pressure, thereby reducing coloring and impurities. A method for producing polyarylate has been proposed. 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 has a total cost including environmental protection problems and recycling of organic solvent. The rise was significant.
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 has 20 to 80% by weight of an antioxidant added to the total dihydric phenol to cause a polymerization reaction to reduce the residual monomer oxidant, The inventors have found that polyarylate can be produced and have completed the present invention.

That is, the gist of the present invention is as follows.
(A) In the production process of polyarylate of the following formula (1) in which a divalent aromatic carboxylic acid halide, a biphenyl structure and a divalent phenol containing a bisphenol structure are produced by an interfacial polycondensation reaction, The manufacturing method of polyarylate characterized by adding 20 to 80 weight% of antioxidant with respect to this.
(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.)
(B) The method for producing polyarylate according to (a), wherein the antioxidant is sodium hyposulfite.
(C) Inherent viscosity is 0.85 to 1.80 dl / g, carboxyl value is 30 mol / t or less, glass transition point (Tg) is 195 ° C. or more, and content of quinone oxide of divalent phenol Is 30 ppm or less, and the amount of residual sulfur is 20 ppm or less.

  According to the present invention, it is possible to economically produce a polyarylate having little residual quinone oxide of dihydric phenol and having excellent electrical characteristics, in particular, insulating characteristics. In addition, 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, which 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.

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

  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. A mixture of 10 to 90 mol% of terephthalic acid halide and 90 to 10 mol% of 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. Specific examples of the biphenols include 4,4′-dihydroxybiphenyl, 2-methyl-4,4′-dihydroxybiphenyl, 3-methyl-4,4′-dihydroxybiphenyl, 3,3′-dimethyl-4,4. '-Dihydroxybiphenyl, 2,2'-dimethyl-4,4'-dihydroxybiphenyl, 2,3'-dimethyl-4,4'-dihydroxybiphenyl, 3,3'-di-tert-butyl-4,4 '-Dihydroxybiphenyl, 3,3'-dimethoxy-4,4'-dihydroxybiphenyl, 3,3', 5,5'-tetramethyl-4,4'-dihydroxybiphenyl, 3,3 ', 5,5' -Tetra-tert-butyl-4,4'-dihydroxybiphenyl, 2,2'-dihydroxy-3,3'-dimethylbiphenyl, 2,2'-dihydroxy-3,3 ', , 5'-tetramethyl-biphenyl, 2,2 '3,3' include 5,5'-hexamethyl-4,4'-biphenol. From the viewpoint of solvent solubility of the produced polyarylate, 3,3 ′, 5,5′-tetramethyl-4,4-dihydroxybiphenyl is preferred.

  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 (1) 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.

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

  The polymerization catalyst needs to be a quaternary ammonium salt having 3 or 4 ethyl groups or butyl groups. Specific materials include tri-n-butylbenzylammonium chloride, tri-n-butylbenzylammonium bromide, tri-n-butylbenzylammonium hydroxide, tri-n-butylbenzylammonium hydrogen sulfate, tetra-n- Examples include butylammonium chloride, tetra-n-butylammonium bromide, tetra-n-butylammonium hydroxide, and 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 total 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 optimum addition amount of the polymerization catalyst is suitably in the range of 0.5 to 1.2 mol%.

  Moreover, in order not to oxidize dihydric phenol in an alkaline solution, it is necessary to add antioxidant. In particular, in the present invention, biphenols that are easily oxidized to diphenoquinone as dihydric phenol are used, which is essential from the stability of the polymerization reaction.

  As the antioxidant, sulfite is preferred. Examples of sulfites include various sulfites. Specific examples include sodium sulfite, sodium hyposulfite (also known as hydrosulfite), sulfur dioxide, potassium sulfite, and sodium hydrogen sulfite. Among these, sodium hyposulfite is most suitable from the viewpoint of the antioxidant effect and the reduction of environmental burden.

  As a constituent requirement of the present invention, it is necessary to add the antioxidant in an amount of 20 to 80% by weight based on the total dihydric phenol. Usually, as an addition amount of the antioxidant, a sufficient antioxidant effect is exhibited by adding about 0.1 to 1.0% by weight with respect to the total dihydric phenol. However, regarding the polyarylate of the present invention, since an easily oxidizable biphenol is used as a reaction monomer, a target resin can be produced for the first time by using a large amount of an antioxidant. Moreover, it is necessary to change the addition amount according to the composition ratio of the biphenols, and the amount of the antioxidant to be added increases as the ratio of the biphenols increases.

  When the addition amount is less than 20% by weight, there is no coloration as in the present invention, and a polyarylate with few impurities cannot be produced. Moreover, when 80 weight% or more is added, the amount of sulfur remaining in the polyarylate increases, which is a problem.

  The amount of sulfur remaining in the polyarylate is preferably 20 ppm or less. When it is more than 20 ppm, the electrical characteristics are deteriorated due to sulfur.

  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, 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, Valent aromatic carboxylic acid halide is dissolved. A high molecular weight polyarylate is 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.

  The inherent viscosity (ηinh) of the polyarylate obtained in the present invention is preferably 0.85 to 1.80 dl / g, and most preferably 0.95 to 1.50 dl / g. If the inherent viscosity is less than 0.85 dl / g, the solution viscosity of the coating solution is low when the mechanical properties of polyarylate are insufficient or when a coating solution is prepared by dissolving the coating solution in a solvent. Since it may be too much to coat, 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 be difficult. Absent. 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.

  Moreover, it is preferable that the range of the carboxyl value of the polyarylate in this invention is 30 mol / t or less. If it exceeds 30 mol / t, the electrical properties are significantly reduced when a coating is formed.

  The glass point transfer (Tg) of the polyarylate in the present invention is preferably 195 ° C. or higher. When it is lower than 195 ° C., there is a problem in terms of heat resistance.

  The residual amount of the bisphenol quinone oxide in the polyarylate is preferably 30 ppm or less. If it 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 produced by the method 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 used as a film-forming resin. it can. 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 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 produced according to the present invention is suitably used as a binder resin or a resin for a film, and is used as a coating liquid as described above by a casting method, or by a melt extrusion method or a calendering method. A coating or film having excellent electrical characteristics 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.

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 dissolving 0.3 g of a sample in 20 ml of methylene chloride in an Erlenmeyer flask, an indicator (phenollet) was added, and the solution was adjusted 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 body The sample was subjected to Soxhlet extraction with acetonitrile, and then subjected to HPLC measurement on the liquid filtered through a disk filter (pore diameter 0.45 μm) under the following conditions.
(HPLC measurement conditions)
<Apparatus> HP1100 HPLC system manufactured by Hewlett Packard
<Column> Wakopak Wakosil 5C18-200T 4.6mm x 150mm (40 ° C)
<Detector> UV 210nm
<Injection volume> 10μm
<Eluent> AcCN / H20 = 40/60 (Flow rate) 1.0ml / min.
5) Residual sulfur amount Using a total chlorine / sulfur analyzer (TSX-10, manufactured by Mitsubishi Chemical Corporation), measurement was performed at an electric furnace inlet temperature of 850 ° C and an electric furnace outlet temperature of 950 ° C.

Example 1
In a reaction vessel equipped with a stirrer, 22.15 g (0.091 mol) of 3,3 ′, 5,5′-tetramethyl-4,4′-dihydroxybiphenyl (hereinafter abbreviated as TMBP) as a divalent phenol 23.43 g (0.091 mol) of 2,2-bis (3-methyl-4-hydroxyphenyl) propane (hereinafter abbreviated as bisphenol C), 50% by weight of sodium hyposulfite as an antioxidant with respect to dihydric phenol .79 g, p-tert-butylphenol 0.46 g (0.003 mol) as a molecular weight modifier, 17.31 g (0.433 mol) sodium hydroxide, tri-n-butylbenzylammonium chloride as a polymerization catalyst In order to prepare 0.7 mol% with respect to the number of moles, 0.39 g (0.001274 mol) was dissolved in 1223 ml of water (aqueous phase) . Separately, 37.42 g (0.184 mol) of a mixture of terephthalic acid chloride / isophthalic acid chloride = 1/1 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. After the polymerization was stopped, the aqueous phase and the organic phase were decanted and separated. After removing the aqueous phase (alkaline water), acetic acid was added until pH = 4 while adding an equal amount of ion-exchanged water and stirring. Further, the operation of stirring for 20 minutes and then decanting for 20 minutes to remove the aqueous phase and replace with new ion-exchanged water was repeated three times. The polymer solution, which is an 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 powdery polymer. After dehydrating the powder polymer, the water-containing powder polymer containing a small amount of water was dried with a vacuum dryer at 120 ° C. for 24 hours under reduced pressure to obtain a polyarylate resin.

Examples 2-5
A polyarylate resin was produced in the same manner as in Example 1 except that the amount of the antioxidant of Example 1 and the composition of the polyarylate resin were changed.

Comparative Examples 1-5
A polyarylate resin was produced in the same manner as in Example 1 except that the amount of the antioxidant of Example 1 and the composition of the polyarylate resin 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 (3)

In the production process of polyarylate of the following formula (1) in which a divalent aromatic carboxylic acid halide, a biphenyl structure and a divalent phenol containing a bisphenol structure are produced by an interfacial polycondensation reaction, A method for producing polyarylate, comprising adding 20 to 80% by weight of an antioxidant.
(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.) The method for producing polyarylate according to claim 1, wherein the antioxidant is sodium hyposulfite. It has an inherent viscosity of 0.85 to 1.80 dl / g, a carboxyl number of 30 mol / t or less, a glass transition point (Tg) of 195 ° C. or more, and a content of quinone oxide of a dihydric phenol of 30 ppm or less. Polyarylate characterized in that the amount of residual sulfur is 20 ppm or less.