JP2011214015A - Polycarbonate resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for efficiently and stably producing a polycarbonate resin having excellent light resistance, transparency, hue, heat resistance, thermal stability and mechanical strength and stable performances.SOLUTION: The method for producing a polycarbonate resin comprises carrying out polycondensation by transesterification using a catalyst and, as raw material monomers, a carbonic acid diester and a dihydroxy compound, in a multistage process in a plurality of reactors. The carbonic acid diester used is purified by distillation. The dihydroxy compound comprises a plurality of kinds of dihydroxy compounds, in which at least one compound includes a -CH-O- moiety as a part of the structure (however, a moiety as a part of -CH-O-H is excluded). At least one reactor gives a distillation amount of monohydroxy compounds as a byproduct of the transesterification reaction, amounting to 20% or more of the theoretical distillation amount, and has an internal volume of 20 L or more, including a heating means for heating the reactor by use of a heating medium, and a reflux cooler, wherein the temperature difference between the heating medium and a reaction liquid in the reactor is at least 5°C. When the difference between a molar percentage of the dihydroxy compound upon feeding the compound as a raw material to the reactor, and a molar percentage of dihydroxy compound structural units in the obtained polycarbonate resin is divided by the molar percentage of the dihydroxy compound upon feeding the compound as a raw material to the reactor, the obtained value in terms of an absolute value falls in a specified range.

Description

  The present invention relates to a method for efficiently and stably producing a polycarbonate resin having excellent light resistance, transparency, hue, heat resistance, thermal stability, and mechanical strength and stable performance.

  Polycarbonate resins generally contain bisphenols as monomer components and take advantage of transparency, heat resistance, mechanical strength, etc., so-called electrical and electronic parts, automotive parts, optical recording media, optical fields such as lenses, etc. Widely used as engineering plastics. However, for optical compensation film applications such as flat panel displays, which have been rapidly spreading recently, more advanced optical properties such as low birefringence and low photoelastic coefficient have been required. With existing aromatic polycarbonates, It is no longer possible to meet that demand.

  Conventional polycarbonates are manufactured using raw materials derived from petroleum resources. However, in recent years, there is a concern about the exhaustion of petroleum resources, and there is a need to provide polycarbonates using raw materials obtained from biomass resources such as plants. It has been demanded. In addition, it is feared that global warming due to the increase and accumulation of carbon dioxide emissions will lead to climate change, etc., so that carbon-neutral plant-derived monomers are used as raw materials even after disposal after use. There is a need to develop polycarbonate.

Under such circumstances, there has been proposed a method for obtaining a polycarbonate while using a special dihydroxy compound as a monomer component and distilling off a monohydroxy compound by-produced by transesterification with a carbonic acid diester under reduced pressure (for example, Patent Documents 1 to 3). 6).
However, since the dihydroxy compound having such a special structure has a lower boiling point than bisphenols, volatilization during the transesterification reaction performed under high temperature and reduced pressure is severe, not only causing deterioration of the raw material unit, The problem is that it becomes difficult to control the terminal group concentration affecting the quality to a predetermined value, and when multiple types of dihydroxy compounds are used, the molar ratio of the dihydroxy compounds used changes during the polymerization, There was a problem that a polycarbonate resin having a molecular weight and a composition of the above could not be obtained.

In order to solve this problem, methods such as lowering the polymerization temperature or reducing the degree of decompression can be considered, but in this method, although the volatilization of the monomer is suppressed, there is a dilemma that causes a decrease in productivity. there were.
Further, although a method using a polymerization reactor having a specific reflux condenser has been proposed (see Patent Document 7), the improvement of the raw material basic unit is not yet satisfactory, and further improvement is demanded.

  Furthermore, since the by-produced monohydroxy compound takes away a large amount of latent heat of evaporation when it is distilled off, it is necessary to heat it with a heat medium (heat medium) to keep it at a predetermined polymerization temperature, but the scale is large. Then, since the heat transfer area per unit reaction liquid in the reactor becomes small, it becomes necessary to heat with a higher temperature heating medium. This means that the reaction liquid in the part in contact with the wall surface through which the heat medium circulates is heated at a higher temperature, and only significantly promotes the volatilization of the dihydroxy compound having a low boiling point that touches the wall surface. However, there is a problem that the quality deteriorates due to thermal degradation in the vicinity of the wall surface, and the problem becomes more serious as the scale becomes larger.

International Publication No. 04/111106 Pamphlet Japanese Patent Laid-Open No. 2006-232897 JP 2006-28441 A JP 2008-24919 A JP 2009-91404 A JP 2009-91417 A JP 2008-56844 A

  The object of the present invention is to eliminate the above-mentioned conventional problems, and to efficiently and stably produce a polycarbonate resin having excellent light resistance, transparency, hue, heat resistance, thermal stability and mechanical strength, and having stable performance. It is to provide a method of manufacturing.

  As a result of intensive investigations to solve the above problems, the present inventor distills from a reactor in a method of producing a polycarbonate resin by polycondensation by a transesterification method using a carbonic diester and a dihydroxy compound as monomers. The present inventors have found a method for producing a polycarbonate resin having excellent light resistance, transparency, hue, heat resistance, thermal stability, mechanical strength and stable performance by making the amount of the monomer to be a specific amount or less.

That is, the gist of the present invention resides in the following [1] to [16].
[1] A method for producing a polycarbonate resin by polycondensation by a transesterification in a plurality of reactors using a carbonic acid diester and a dihydroxy compound as raw materials and a catalyst in multiple stages,
The dihydroxy compound includes at least a dihydroxy compound having a site represented by the following general formula (1) in a part of the structure;
At least one of the reactors in which the distillate of the monohydroxy compound produced as a by-product by the transesterification distills 20% or more of the theoretical distillate is used to heat the reactor using a heat medium having an internal volume of 20 L or more. A reactor having a heating means and a reflux condenser, wherein the temperature difference between the temperature of the heat medium and the reaction liquid in the reactor is at least 5 ° C., and
A method for producing a polycarbonate resin, characterized in that the total amount of monomers distilled out in all reaction stages is 10% by weight or less based on the total amount of raw material monomers.

(However, the site represented by the above general formula (1) unless it is part of _-CH 2 -O-H.)
[2] A method of producing a polycarbonate resin by polycondensation by a transesterification in a plurality of stages using a catalyst and a carbonic acid diester and a dihydroxy compound as raw materials monomers in a plurality of stages,
The dihydroxy compound is composed of a plurality of types of dihydroxy compounds, and at least one of them is a dihydroxy compound having a site represented by the following general formula (1) as part of the structure;
At least one of the reactors in which the distillate of the monohydroxy compound produced as a by-product by the transesterification distills 20% or more of the theoretical distillate is used to heat the reactor using a heat medium having an internal volume of 20 L or more. A reactor having a heating means and a reflux condenser, wherein the temperature difference between the temperature of the heating medium and the reaction liquid in the reactor is at least 5 ° C. or more, and when the reactor is charged as a raw material. The absolute value of the value obtained by dividing the difference between the molar percentage of the dihydroxy compound and the molar percentage of the structural unit of the dihydroxy compound in the obtained polycarbonate resin by the molar percentage of the dihydroxy compound at the time of charging as a raw material to the reactor, It is 0.03 or less for at least one dihydroxy compound, and any dihydroxy compound does not exceed 0.05. Manufacturing method of a polycarbonate resin.

(However, the site represented by the above general formula (1) unless it is part of _-CH 2 -O-H.)
[3] The production method according to [1] or [2], wherein the boiling point at atmospheric pressure of at least one of the dihydroxy compounds is 300 ° C. or lower.
[4] The method for producing a polycarbonate resin according to any one of [1] to [3], wherein at least three reactors are used.
[5] The method for producing a polycarbonate resin according to any one of [1] to [4], wherein the temperature of the refrigerant introduced into the reflux condenser is 45 to 180 ° C. at the inlet of the reflux condenser.
[6] The method for producing a polycarbonate resin according to any one of [1] to [5], wherein the total amount of monomers distilled out in all the reaction steps is 3% by weight or less based on the total amount of raw material monomers.
[7] In the first reactor in which the distillation amount of the monohydroxy compound by-produced by the transesterification distills 20% or more of the theoretical distillation amount, lithium and long-period periodic table 2 [1] to [6], wherein at least one metal compound selected from the group consisting of group metals is used in a total amount of metal atoms of 20 μmol or less per 1 mol of all dihydroxy compounds used as raw materials. Of producing a polycarbonate resin.
[8] The method for producing a polycarbonate resin according to [7], wherein the catalyst is at least one metal compound selected from the group consisting of a magnesium compound and a calcium compound.
[9] The method for producing a polycarbonate resin according to any one of [1] to [8], wherein the maximum temperature of the reaction solution in all reaction stages is less than 250 ° C.
[10] The method for producing a polycarbonate resin according to any one of [1] to [9], wherein the maximum temperature of the heat medium is less than 265 ° C.
[11] The [1] to [10], wherein the dihydroxy compound includes a compound of the following general formula (2) and at least one compound selected from the group consisting of an aliphatic dihydroxy compound and an alicyclic dihydroxy compound. The manufacturing method of the polycarbonate resin in any one.

[12] A polycarbonate resin obtained by the method according to any one of [1] to [11], wherein a molded article (thickness 3 mm) molded from the polycarbonate resin has a light transmittance at a wavelength of 350 nm of 60. % Of polycarbonate resin.
[13] A polycarbonate resin obtained by the method according to any one of [1] to [11], wherein a molded product (thickness 3 mm) molded from the polycarbonate resin has a light transmittance of 30 at a wavelength of 320 nm. % Of polycarbonate resin.
[14] A polycarbonate resin obtained by the method according to any one of [1] to [11], wherein a molded body (thickness 3 mm) molded from the polycarbonate resin is obtained at 63 ° C. and a relative humidity of 50%. Yellow index (YI) in accordance with ASTM D1925-70 measured with transmitted light after irradiation for 100 hours at a wavelength of 300 nm to 400 nm and irradiance of 1.5 kW / m ² using a metal halide lamp. A polycarbonate resin having a value of 12 or less.
[15] A polycarbonate resin obtained by the method according to any one of [1] to [11], wherein an initial yellow index value of a molded body (thickness 3 mm) molded from the polycarbonate resin is 7 or less. Polycarbonate resin characterized by being.
[16] A polycarbonate resin obtained by the method according to any one of [1] to [11], wherein an initial yellow index value of a molded body (thickness 3 mm) molded from the polycarbonate resin, ASTM measured with transmitted light after the molded body was irradiated for 100 hours at an irradiance of 1.5 kW / m ² with a wavelength of 300 nm to 400 nm using a metal halide lamp in an environment of 63 ° C. and 50% relative humidity. A polycarbonate resin, characterized in that the absolute value of the difference from the yellow index (YI) value in accordance with D1925-70 is 6 or less.
[17] A polycarbonate resin obtained by the method according to any one of [1] to [11], wherein a molded product (thickness 3 mm) molded from the polycarbonate resin has an L * value of 96.3 or more. Polycarbonate resin characterized by being.

  According to the present invention, not only has excellent light resistance, but also excellent transparency, hue, heat resistance, moldability, and mechanical strength, and the field of injection molding such as electrical / electronic parts and automotive parts, Film, sheet field, bottle, container field, camera lens, finder lens, lens application such as CCD and CMOS lens, retardation film used for liquid crystal and plasma display, diffusion sheet, polarizing film, etc. It is possible to efficiently and stably produce polycarbonate resin with performance applicable to a wide range of fields such as sheet, optical disc, optical material, optical component, dye and charge transfer agent Become.

DESCRIPTION OF EMBODIMENTS Embodiments of the present invention will be described in detail below. However, the description of the constituent elements described below is an example (representative example) of an embodiment of the present invention. It is not limited to the contents.
A first invention in the present invention is a method for producing a polycarbonate resin by polycondensation by transesterification in a plurality of reactors in multiple stages using a carbonic acid diester and a dihydroxy compound as a catalyst and a raw material monomer, The dihydroxy compound includes at least a dihydroxy compound having a site represented by the following general formula (1) in a part of the structure;
At least one of the reactors in which the distillate of the monohydroxy compound produced as a by-product by the transesterification distills 20% or more of the theoretical distillate is used to heat the reactor using a heat medium having an internal volume of 20 L or more. A reactor having a heating means and a reflux condenser, wherein the temperature difference between the temperature of the heat medium and the reaction liquid in the reactor is at least 5 ° C., and
The total amount of monomers distilled out in all reaction stages is 10% by weight or less with respect to the total amount of raw material monomers.

(However, the site represented by the above general formula (1) unless it is part of _-CH 2 -O-H.)
In the present invention, at least one of the reactors in which the monohydroxy compound distillates at least 20% of the theoretical distillate has an internal volume of 20 L or more, preferably 30 L or more. As described above, the effect of the present invention increases as the internal volume of the reactor increases.

  In the method of the present invention, the carbonic acid diester and the dihydroxy compound are polycondensed (in some cases, simply referred to as polymerization) by transesterification in multiple stages using a plurality of reactors in the presence of a catalyst described later. In the reaction, a monohydroxy compound (for example, phenol when diphenyl carbonate is used as the carbonic acid diester) is produced as a by-product. Therefore, the by-produced monohydroxy compound is polymerized while being distilled out of the system, but in the initial stage of polymerization, the amount of monohydroxy compound by-product per unit time is large, and it takes a lot of latent heat of evaporation. In the present invention, a heating means for heating at least one of the reactors in which the distillate of the monohydroxy compound is distilled at 20% or more of the theoretical distillate using a heat medium is provided. The temperature of the introduced heat medium is higher than the temperature of the reaction liquid in the reactor (hereinafter sometimes referred to as “internal temperature”), that is, the temperature difference is at least 5 ° C. (heat Medium temperature> internal temperature).

  Here, the theoretical distillation amount of the monohydroxy compound in the present invention is twice the number of moles of carbonic acid diester used as a raw material, and a reactor that distills 20% or more of the theoretical distillation amount is a batch. In the case of the formula reaction, it is calculated from the total amount of the monohydroxy compound distilled from one reactor with respect to the amount of the carbonic diester compound initially charged as a raw material, and becomes 20% or more of the theoretical distillation amount. In the case of continuous reaction, it is calculated from the amount of monohydroxy compound per unit time distilled from one reactor with respect to the amount per unit time of carbonic diester fed as a raw material, It means a reactor that is 20% or more of the theoretical distillation amount.

  Further, as a heating means for heating the reactor using a heat medium, a jacket type (hereinafter sometimes simply referred to as a heat medium jacket) provided around the reactor (entirely or partially), Examples of the type include an internal coil installed inside the reactor and a type of heat exchanger provided outside the reactor. The heating means is preferably a heat medium jacket. When using a heat medium jacket, in order not to make the temperature of the heat medium in the jacket excessively high, an internal coil is also installed inside the reactor, and heat is applied also from the inside of the reactor to reduce the heat transfer area. It is effective to increase it.

  When the temperature difference between the temperature of the heat medium and the reaction liquid is less than 5 ° C., the heat balance of the reactor is deteriorated, and the temperature of the reaction liquid may not be set to a predetermined temperature. In particular, when the size of the reactor is increased, for example, when the heating means is a heat medium jacket, the heat transfer area of the heat medium jacket tends to decrease with respect to the internal volume of the reactor. It is desirable to increase the temperature difference between the liquids, preferably 10 ° C. or higher, and more preferably 15 ° C. or higher.

On the other hand, if the temperature difference between the temperature of the heat medium and the reaction liquid becomes too large, not only will the amount of distillate of the raw material monomer increase, but the content will also become severely deteriorated by heat. Preferably it is 40 degrees C or less, Most preferably, it is 30 degrees C or less.
The temperature of the heat medium to be introduced may be appropriately determined depending on the temperature of the reaction liquid to be achieved, but if the temperature of the heat medium becomes too high, the amount of raw material monomer distills too much, so the highest temperature is preferably It is less than 265 ° C, more preferably less than 260 ° C, and particularly preferably less than 255 ° C.

When the temperature of the heat medium is higher than the temperature of the reaction solution by 5 ° C. or more, it may be always higher by 5 ° C. or more during the reaction time in one reactor, You may go only for a period. Generally, the former is used for continuous reactions and the latter is used for batch reactions.
In the present invention, the temperature of the heat medium is a temperature before being introduced into the heating means, for example, when the heating means is a heat medium jacket, it is provided around the reactor (entirely or partially). The temperature of the heat medium before being introduced into the heat medium jacket. In the present invention, the temperature of the reaction liquid refers to the temperature of the reaction liquid measured by a measuring instrument such as a thermocouple .

  In the present invention, the internal temperature of at least one of the reactors in which the distillation amount of the monohydroxy compound by-produced by the polymerization reaction is 20% or more of the theoretical distillation amount is usually 140 to 270 ° C, preferably 180 to 240 ° C. More preferably, it is 200-230 degreeC. If the internal temperature is excessively high, not only will the amount of distillate of the raw material monomer increase, but thermal deterioration will also become severe, and if it is excessively low, the reaction rate will decrease and production efficiency will decrease.

In the present invention, in order to suppress the amount of the monomer to be distilled, at least one of the reactors in which the distillate of the monohydroxy compound distills 20% or more of the theoretical distillate is used. It is characterized by comprising.
The temperature of the refrigerant introduced into the reflux cooler is preferably 45 to 180 ° C., more preferably 80 to 150 ° C., and particularly preferably 100 to 130 ° C. at the inlet of the reflux cooler. If the temperature of the refrigerant is too high, the amount of reflux decreases and the effect tends to decrease. On the other hand, if the temperature is too low, the distillation efficiency of the monohydroxy compound that should be distilled off tends to decrease. As the refrigerant, hot water, steam, heat medium oil or the like is used, and steam or heat medium oil is preferable.

In order to suppress the amount of the monomer to be distilled, the reflux condenser is preferably provided in a reactor in which the distillate of the monohydroxy compound is distilled at 10% or more of the theoretical distillate. In the method of the present invention, it is important that the total amount of monomers distilled out in all reaction stages is 10% by weight or less based on the total amount of raw material monomers.
Here, the total amount of monomers distilled in all the reaction stages (hereinafter sometimes referred to as “the amount of monomers to be distilled”) is the total amount of all monomers distilled from the start to the end of the transesterification reaction. It is.

  If the amount of monomer to be distilled exceeds 10% by weight based on the total amount of raw material monomers, not only will the raw material basic unit be deteriorated, but it will be difficult to control the terminal group concentration affecting the quality to a predetermined value. In the case of using a plurality of dihydroxy compounds, there is a possibility that the molar ratio of the dihydroxy compound to be used changes during the polymerization, and a polycarbonate resin having a desired molecular weight and composition cannot be obtained.

The amount of the monomer to be distilled is preferably 5% by weight or less, more preferably 3% by weight or less, and particularly preferably 2% by weight or less based on the total amount of raw material monomers.
The smaller the amount of monomer distilled, the greater the improvement of the raw material unit, while the internal temperature and heating medium temperature are excessively lowered, the pressure is excessively increased, the amount of catalyst is increased, the polymerization time is increased. The lower limit is usually 0.2% by weight, preferably 0.4% by weight, and more preferably 0.6% by weight. is there.

The amount of monomer to be distilled as defined in the present invention is achieved by appropriately selecting the type and amount of the catalyst, the temperature of the reaction solution, the temperature of the heating medium, the reaction pressure, the residence time, the reflux conditions and the like as described above. Can do.
For example, in the initial stage of polymerization, a prepolymer is obtained at a relatively low temperature and low vacuum, and in the latter stage of polymerization, the molecular weight is increased to a predetermined value at a relatively high temperature and high vacuum. It is important to select the temperature, internal temperature, and pressure in the reaction system appropriately. For example, if either the temperature or the pressure is changed too quickly before the polymerization reaction reaches a predetermined value, the unreacted monomer will be distilled, causing the molar ratio of the dihydroxy compound and the carbonic acid diester to change, resulting in a decrease in the polymerization rate. Or a polymer having a predetermined molecular weight or terminal group may not be obtained.

In order to maintain the polymerization rate appropriately and suppress the distillation of the monomer while maintaining the hue, thermal stability, light resistance, etc. of the final polycarbonate resin, Selection is also important.
In the method of the present invention, the polycarbonate resin is produced in multiple stages using a catalyst and a plurality of reactors using a catalyst. The reason for carrying out the polymerization in a plurality of reactors is that the reaction is performed at the initial stage of the polymerization reaction. Since many monomers are contained in the liquid, it is important to suppress the volatilization of the monomers while maintaining the necessary polymerization rate. In the late stage of the polymerization reaction, by-products are generated in order to shift the equilibrium to the polymerization side. This is because it is important to sufficiently distill off the monohydroxy compound. Thus, in order to set different polymerization reaction conditions, it is preferable from the viewpoint of production efficiency to use a plurality of polymerization reactors arranged in series.

As described above, the number of reactors used in the method of the present invention may be at least two or more. However, from the viewpoint of production efficiency and the like, three or more, preferably 3 to 5, particularly preferably 4 are used. One.
In the present invention, if there are two or more reactors, a plurality of reaction stages having different conditions may be further provided in the reactor, and the temperature and pressure may be changed stepwise or continuously. .

That is, for example, when two reactors are used and the reaction conditions are changed to make two-stage polymerization, or when two reactors are used, the first reactor has two reaction stages with different conditions. And a case where the second reactor has one reaction condition and has three stages.
In the present invention, the catalyst described later can be added to the raw material preparation tank, the raw material storage tank, or can be added directly to the reactor. However, from the viewpoint of supply stability and polymerization control, the catalyst is supplied to the reactor. A catalyst supply line is installed in the middle of the raw material line before being fed, and preferably supplied as an aqueous solution.

If the temperature of the transesterification reaction is too low, it may lead to a decrease in productivity and an increase in the thermal history of the product, and if it is too high, it may not only cause vaporization of the monomer but also promote the decomposition and coloring of the polycarbonate resin. .
As described above, the internal temperature of at least one reactor in which the distillate of the by-produced monohydroxy compound distills 20% or more of the theoretical distillate is 140 to 270 ° C., preferably 180, as the maximum temperature. Although it is -240 degreeC, More preferably, it is 200-230 degreeC, As other conditions, it is usually 110-1 kPa, Preferably it is 70-5 kPa, More preferably, it is 30-10 kPa (absolute pressure), and usually 0.1 The reaction is carried out for 10 to 10 hours, preferably 0.5 to 3 hours while distilling off the generated monohydroxy compound to the outside of the reaction system.

In the second and subsequent stages, the pressure in the reaction system is gradually reduced from the pressure in the first stage, and the monohydroxy compound that is subsequently generated is removed from the reaction system. Usually, the pressure is 1000 Pa or less, preferably 200 Pa or less, and the maximum internal temperature is 210 to 270 ° C., preferably 220 to 250 ° C.
In particular, in order to suppress the coloring and thermal deterioration of the polycarbonate resin, and to make the amount of monomer to be distilled to 10% by weight or less based on the total amount of raw material monomers, the maximum internal temperature in all reaction stages is less than 250 ° C., In particular, the temperature is preferably 225 to 245 ° C. In the method of the present invention, the by-produced monohydroxy compound is preferably reused as a raw material for carbonic acid diester, bisphenol compound, etc., after purification as necessary from the viewpoint of effective utilization of resources.

A second invention in the present invention is a method for producing a polycarbonate resin by polycondensation by a transesterification reaction in multiple stages in a plurality of reactors using a catalyst and a carbonic acid diester and a dihydroxy compound as raw material monomers. ,
The dihydroxy compound is composed of a plurality of types of dihydroxy compounds, and at least one of them is a dihydroxy compound having a site represented by the following general formula (1) as part of the structure;
At least one of the reactors in which the distillate of the monohydroxy compound produced as a by-product by the transesterification distills 20% or more of the theoretical distillate is used to heat the reactor using a heat medium having an internal volume of 20 L or more. A reactor having a heating means and a reflux condenser, wherein the temperature difference between the temperature of the heat medium and the reaction liquid in the reactor is at least 5 ° C., and
The difference between the molar percentage of the dihydroxy compound at the time of charging as a raw material and the molar percentage of the structural unit of the dihydroxy compound in the obtained polycarbonate resin is determined as the mole of the dihydroxy compound at the time of charging as the raw material. The absolute value of the value divided by percentage is 0.03 or less for at least one dihydroxy compound, and 0.05 for any dihydroxy compound.

(However, the site represented by the above general formula (1) unless it is part of _-CH 2 -O-H.)
More specifically, the reactor, heating means, reflux condenser, each temperature condition, and the like are as described in the first invention. In the second invention, a plurality of types of dihydroxy compounds are used. The mole percentage of each dihydroxy compound used as a raw material and charged to the reactor as a raw material is A, B, C,... N mol%, respectively, and is derived from each dihydroxy compound in the obtained polycarbonate resin. (| (A-A) / A |, | (b-B) / B |, | (c-C) where the molar percentages of the structural units are a, b, c. ) / C |,..., (N-N / N |) is 0.03 or less, preferably 0.02 or less, more preferably 0.01 or less, and particularly preferably 0.005 or less. For any dihydroxy compound Is preferably not more than 0.05, preferably not more than 0.03, more preferably not more than 0.02, particularly preferably not more than 0.01, and preferably not more than 0.005. As described above, this can be achieved by appropriately selecting the type and amount of the catalyst, the temperature (internal temperature) of the transesterification reaction, the temperature of the heat medium, the pressure, the residence time, the reflux conditions, and the like.

(Dihydroxy compound)
In the method for producing a polycarbonate resin of the present invention, a carbonic acid diester and a dihydroxy compound are used as raw material monomers, and at least one of the dihydroxy compounds has a portion represented by the following general formula (1) in a part of the structure. It is a compound (hereinafter, sometimes referred to as “dihydroxy compound of the present invention”). That is, the dihydroxy compound of the present invention refers to a compound containing at least two hydroxyl groups and at least a structural unit of the following general formula (1).

(However, the site represented by the above general formula (1) unless it is part of _-CH 2 -O-H.)
The dihydroxy compound of the present invention is not particularly limited as long as it has a site represented by the above general formula (1) in a part of its structure. Specifically, diethylene glycol, triethylene glycol, Oxyalkylene glycols such as tetraethylene glycol and polyethylene glycol, 9,9-bis (4- (2-hydroxyethoxy) phenyl) fluorene, 9,9-bis (4- (2-hydroxyethoxy) -3-methylphenyl ) Fluorene, 9,9-bis (4- (2-hydroxyethoxy) -3-isopropylphenyl) fluorene, 9,9-bis (4- (2-hydroxyethoxy) -3-isobutylphenyl) fluorene, 9,9 -Bis (4- (2-hydroxyethoxy) -3-tert-butylphenyl) fluorene 9,9-bis (4- (2-hydroxyethoxy) -3-cyclohexylphenyl) fluorene, 9,9-bis (4- (2-hydroxyethoxy) -3-phenylphenyl) fluorene, 9,9-bis ( 4- (2-hydroxyethoxy) -3,5-dimethylphenyl) fluorene, 9,9-bis (4- (2-hydroxyethoxy) -3-tert-butyl-6-methylphenyl) fluorene 9,9-bis (4- (3-hydroxy-2,2-dimethylpropoxy) phenyl) fluorene or the like, a compound having an aromatic group in the side chain and an ether group bonded to the aromatic group in the main chain, the following formula (2) A compound having a cyclic ether structure such as an anhydrosugar alcohol typified by a dihydroxy compound represented by formula (3) and a spiroglycol represented by the following formula (3). Among them, a compound having a cyclic ether structure represented by the anhydro sugar alcohols represented by the dihydroxy compound represented by the following formula (2), the following equation (3) is preferable.

  These may be used alone or in combination of two or more depending on the required performance of the polycarbonate resin to be obtained.

Examples of the dihydroxy compound represented by the general formula (2) include isosorbide, isomannide and isoidet which are in a stereoisomeric relationship, and these may be used alone or in combination of two or more. It may be used.
Of these dihydroxy compounds, it is preferable to use a dihydroxy compound having no aromatic ring structure from the viewpoint of the light resistance of the polycarbonate resin, and among them, it is abundant as a plant-derived resource and is produced from various easily available starches. Isosorbide obtained by dehydrating and condensing sorbitol is most preferable from the viewpoints of availability and production, light resistance, optical properties, moldability, heat resistance, and carbon neutral.

  In the method for producing a polycarbonate resin of the present invention, a constituent unit derived from a dihydroxy compound other than the above-described dihydroxy compound of the present invention (hereinafter sometimes referred to as “other dihydroxy compound”) is included as a raw material monomer. As other dihydroxy compounds, ethylene glycol, 1,3-propanediol, 1,2-propanediol, 1,4-butanediol, 1,3-butanediol, 1,2-butanediol, 1,5 -Aliphatic dihydroxy compounds such as heptanediol, 1,6-hexanediol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, tricyclodecane dimethanol, pentacyclo Pentadecane dimethanol, 2,6- Alicyclic dihydroxy such as carindimethanol, 1,5-decalindimethanol, 2,3-decalindimethanol, 2,3-norbornanedimethanol, 2,5-norbornanedimethanol, 1,3-adamantandimethanol, etc. Compound, 2,2-bis (4-hydroxyphenyl) propane [= bisphenol A], 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane, 2,2-bis (4-hydroxy-3) , 5-diethylphenyl) propane, 2,2-bis (4-hydroxy- (3,5-diphenyl) phenyl) propane, 2,2-bis (4-hydroxy-3,5-dibromophenyl) propane, 2, 2-bis (4-hydroxyphenyl) pentane, 2,4′-dihydroxy-diphenylmethane, bis (4-hydroxyphenyl) Nyl) methane, bis (4-hydroxy-5-nitrophenyl) methane, 1,1-bis (4-hydroxyphenyl) ethane, 3,3-bis (4-hydroxyphenyl) pentane, 1,1-bis (4 -Hydroxyphenyl) cyclohexane, bis (4-hydroxyphenyl) sulfone, 2,4'-dihydroxydiphenylsulfone, bis (4-hydroxyphenyl) sulfide, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxy-3, 3'-dichlorodiphenyl ether, 9,9-bis (4- (2-hydroxyethoxy-2-methyl) phenyl) fluorene, 9,9-bis (4-hydroxyphenyl) fluorene, 9,9-bis (4-hydroxy Aromatic bisphenols such as 2-methylphenyl) fluorene .

  Among these, from the viewpoint of improving the hue of the polycarbonate resin, it is preferably at least one compound selected from the group consisting of aliphatic dihydroxy compounds and alicyclic dihydroxy compounds. 3-propanediol, 1,4-butanediol, and 1,6-hexanediol are preferable, and 1,4-cyclohexanedimethanol and tricyclodecanedimethanol are particularly preferable as the alicyclic dihydroxy compound.

  By using these other dihydroxy compounds, it is possible to obtain effects such as improvement in flexibility of polycarbonate resin, improvement in heat resistance, improvement in moldability, etc., but structural units derived from other dihydroxy compounds When the content ratio is too large, mechanical properties and heat resistance may be lowered. Therefore, the ratio of the structural unit derived from the dihydroxy compound of the present invention to the structural unit derived from all dihydroxy compounds is 20 mol. % Or more, preferably 30 mol% or more, and particularly preferably 50 mol% or more.

Among the dihydroxy compounds of the present invention and other dihydroxy compounds, when the boiling point at atmospheric pressure of at least one dihydroxy compound is 300 ° C. or lower, the dihydroxy compound is easily volatilized during the polymerization reaction. The effect is greatly achieved, and the effect is even greater when the temperature is 290 ° C. or lower.
The dihydroxy compound of the present invention may contain a stabilizer such as a reducing agent, antioxidant, oxygen scavenger, light stabilizer, antacid, pH stabilizer, heat stabilizer, etc. Since the dihydroxy compound is easily altered, it is preferable to contain a basic stabilizer. Basic stabilizers include Group 1 or Group 2 metal hydroxides, carbonates, phosphates, phosphites, hypophosphites in the Long Periodic Table (Nomenclature of Inorganic Chemistry IUPAC Recommendations 2005). Acid salts, borates, fatty acid salts, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, trimethylethylammonium hydroxide, trimethylbenzylammonium hydroxide, trimethylphenylammonium hydroxide , Triethylmethylammonium hydroxide, triethylbenzylammonium hydroxide, triethylphenylammonium hydroxide, tributylbenzylammonium hydroxide, tributylphenylammonium Basic ammonium compounds such as monium hydroxide, tetraphenylammonium hydroxide, benzyltriphenylammonium hydroxide, methyltriphenylammonium hydroxide, butyltriphenylammonium hydroxide, 4-aminopyridine, 2-aminopyridine, N, N -Dimethyl-4-aminopyridine, 4-diethylaminopyridine, 2-hydroxypyridine, 2-methoxypyridine, 4-methoxypyridine, 2-dimethylaminoimidazole, 2-methoxyimidazole, imidazole, 2-mercaptoimidazole, 2-methylimidazole And amine compounds such as aminoquinoline. Of these, Na or K phosphates and phosphites are preferred, and hydrogen phosphate 2Na and hydrogen phosphite 2Na are particularly preferred, because of their effects and ease of distillation removal described below.

The content of these basic stabilizers is not particularly limited, but if it is too small, there is a possibility that the effect of suppressing the alteration of the dihydroxy compound of the present invention may not be obtained, and if it is too much, the modification of the dihydroxy compound may be caused. Therefore, it is usually 0.0001% by weight to 1% by weight, preferably 0.001% by weight to 0.1% by weight, based on the dihydroxy compound of the present invention.
Further, when the dihydroxy compound of the present invention containing these basic stabilizers is used as a raw material for producing polycarbonate resin, the basic stabilizer itself becomes a polymerization catalyst, and it becomes difficult to control the polymerization rate and quality. In order to deteriorate the initial hue and consequently deteriorate the light resistance of the molded product, it is preferable to remove the basic stabilizer by ion exchange resin or distillation before using it as a raw material for producing the polycarbonate resin.

  When the dihydroxy compound of the present invention has a cyclic ether structure such as isosorbide, it is likely to be gradually oxidized by oxygen. It is important to use an oxygen agent or the like or handle it under a nitrogen atmosphere. When isosorbide is oxidized, decomposition products such as formic acid may be generated. For example, when isosorbide containing these decomposition products is used as a polycarbonate resin production raw material, the resulting polycarbonate resin may be colored, and may not only significantly deteriorate the physical properties but also affect the polymerization reaction. In some cases, a high molecular weight polymer cannot be obtained.

  In order to obtain the dihydroxy compound of the present invention which does not contain the above oxidative decomposition product, and in order to remove the above basic stabilizer, it is preferable to carry out distillation purification. The distillation in this case may be simple distillation or continuous distillation, and is not particularly limited. As distillation conditions, it is preferable to carry out distillation under reduced pressure in an inert gas atmosphere such as argon or nitrogen. In order to suppress thermal denaturation, it is 250 ° C. or lower, preferably 200 ° C. or lower, particularly 180 °. It is preferable to carry out under the conditions of ℃ or less.

  By such purification by distillation, the dihydroxy compound of the present invention is contained by adjusting the formic acid content in the dihydroxy compound of the present invention to 20 ppm by weight or less, preferably 10 ppm by weight or less, particularly preferably 5 ppm by weight or less. When a dihydroxy compound is used as a raw material for producing a polycarbonate resin, it is possible to produce a polycarbonate resin excellent in hue and thermal stability without impairing polymerization reactivity. The formic acid content is measured by ion chromatography.

(Carbonated diester)
In the present invention, a polycarbonate resin can be obtained by polycondensation by a transesterification reaction using a dihydroxy compound containing the above-described dihydroxy compound of the present invention and a carbonic acid diester as raw materials. Examples of the carbonic acid diester used in the present invention include those represented by the following general structural formula (4). These carbonic acid diesters may be used alone or in combination of two or more.

(In General Formula (4), A ¹ and A ² are a substituted or unsubstituted aliphatic group having 1 to 18 carbon atoms or a substituted or unsubstituted aromatic group, and A ¹ and A ² are the same. Or different.)
Examples of the carbonic acid diester represented by the general formula (4) include diphenyl carbonate (hereinafter sometimes abbreviated as DPC), substituted diphenyl carbonate such as ditolyl carbonate, dimethyl carbonate, diethyl carbonate, and di-t-. Although butyl carbonate etc. are illustrated, Diphenyl carbonate and substituted diphenyl carbonate are preferable, and diphenyl carbonate is particularly preferable. These carbonic acid diesters may be used alone or in combination of two or more. Carbonic acid diesters may contain impurities such as chloride ions, which may hinder the polymerization reaction or worsen the hue of the resulting polycarbonate resin. It is preferable to use what was done.

In the method of the present invention, it is preferable that the raw material dihydroxy compound and carbonic acid diester are mixed uniformly before the transesterification reaction.
The mixing temperature is usually 80 ° C. or higher, preferably 90 ° C. or higher, and the upper limit is usually 250 ° C. or lower, preferably 200 ° C. or lower, more preferably 150 ° C. or lower. Among these, 100 ° C. or higher and 120 ° C. or lower is preferable. If the mixing temperature is too low, the dissolution rate may be slow or the solubility may be insufficient, often causing problems such as solidification, and if the mixing temperature is too high, the dihydroxy compound may be thermally deteriorated. The hue of the polycarbonate resin obtained in this way may deteriorate and adversely affect light resistance and heat resistance.

  In the method of the present invention, the operation of mixing the dihydroxy compound containing the dihydroxy compound of the present invention as a raw material with a carbonic acid diester is usually performed at an oxygen concentration of 10 vol% or less, more preferably 0.0001 vol% to 10 vol%, and more preferably 0.0001 vol%. It is preferable to carry out in an atmosphere of ˜5 vol%, particularly 0.0001 vol% to 1 vol% from the viewpoint of preventing hue deterioration.

  In the present invention, the carbonic acid diester is usually used in a molar ratio of 0.90 to 1.20, preferably 0.95 to 1.10, based on all dihydroxy compounds including the dihydroxy compound of the present invention used in the reaction. More preferably, it is 0.97 to 1.03, and particularly preferably 0.99 to 1.02. If the molar ratio is too large or too small, the rate of the transesterification reaction decreases, which may increase the thermal history during the polymerization reaction, and may deteriorate the hue of the resulting polycarbonate resin. Furthermore, there is a possibility that a desired high molecular weight body cannot be obtained.

(Transesterification catalyst)
In the method of the present invention, as described above, a transesterification catalyst is present when a polycarbonate resin is produced by polycondensing a dihydroxy compound containing the dihydroxy compound of the present invention and a carbonic acid diester by a transesterification reaction. That is, the specific compound is present in the first reactor in which the distillate amount of the monohydroxy compound produced as a by-product by the polymerization reaction is distillate by 20% or more of the theoretical distillate amount.

In the method of the present invention, the transesterification catalyst (polymerization catalyst) can particularly affect the light transmittance at a wavelength of 350 nm and the yellow index (YI) value.
The transesterification catalyst used (hereinafter sometimes simply referred to as a catalyst) is not limited as long as it satisfies the hue, light resistance, etc. of the polycarbonate resin. A basic compound such as a metal compound, a basic boron compound, a basic phosphorus compound, a basic ammonium compound, or an amine compound of a group or group 2 (hereinafter simply referred to as “group 1” or “group 2”) Can be mentioned. Preferably, Group 1 metal compounds and / or Group 2 metal compounds are used.

It is possible to use a basic compound such as a basic boron compound, a basic phosphorus compound, a basic ammonium compound, and an amine compound in combination with the Group 1 metal compound and / or the Group 2 metal compound. It is particularly preferred to use only Group 1 metal compounds and / or Group 2 metal compounds.
In addition, the group 1 metal compound and / or the group 2 metal compound are usually used in the form of a hydroxide or a salt such as a carbonate, a carboxylate, or a phenol salt. From the viewpoint of easiness, a hydroxide, carbonate, and acetate are preferable, and acetate is preferable from the viewpoint of hue and polymerization activity.

  Examples of the Group 1 metal compound include sodium hydroxide, potassium hydroxide, lithium hydroxide, cesium hydroxide, sodium hydrogen carbonate, potassium hydrogen carbonate, lithium hydrogen carbonate, cesium hydrogen carbonate, sodium carbonate, potassium carbonate, lithium carbonate, Cesium carbonate, sodium acetate, potassium acetate, lithium acetate, cesium acetate, sodium stearate, potassium stearate, lithium stearate, cesium stearate, sodium borohydride, potassium borohydride, lithium borohydride, cesium borohydride , Sodium borohydride, potassium borohydride, lithium phenide boron, cesium phenide boron, sodium benzoate, potassium benzoate, lithium benzoate, cesium benzoate, 2 sodium hydrogen phosphate 2 potassium potassium phosphate, 2 lithium hydrogen phosphate, 2 cesium hydrogen phosphate, 2 sodium phenyl phosphate, 2 potassium phenyl phosphate, 2 lithium phenyl phosphate, 2 cesium phenyl phosphate, sodium, potassium, lithium, Examples include cesium alcoholate, phenolate, disodium salt of bisphenol A, 2 potassium salt, 2 lithium salt, 2 cesium salt, etc. Among them, lithium compounds are preferable.

  Examples of the Group 2 metal compound include calcium hydroxide, barium hydroxide, magnesium hydroxide, strontium hydroxide, calcium hydrogen carbonate, barium hydrogen carbonate, magnesium hydrogen carbonate, strontium hydrogen carbonate, calcium carbonate, barium carbonate, magnesium carbonate, Examples include strontium carbonate, calcium acetate, barium acetate, magnesium acetate, strontium acetate, calcium stearate, barium stearate, magnesium stearate, strontium stearate, etc., among which magnesium compounds, calcium compounds and barium compounds are preferred, and polymerization activity and obtained From the viewpoint of the hue of the polycarbonate resin obtained, at least one metal compound selected from the group consisting of a magnesium compound and a calcium compound is more preferable. Most preferably calcium compound.

  Examples of the basic boron compound include tetramethyl boron, tetraethyl boron, tetrapropyl boron, tetrabutyl boron, trimethylethyl boron, trimethylbenzyl boron, trimethylphenyl boron, triethylmethyl boron, triethylbenzyl boron, triethylphenyl boron, tributylbenzyl. Examples include sodium, potassium, lithium, calcium, barium, magnesium, or strontium salts such as boron, tributylphenylboron, tetraphenylboron, benzyltriphenylboron, methyltriphenylboron, butyltriphenylboron, etc. It is done.

Examples of the basic phosphorus compound include triethylphosphine, tri-n-propylphosphine, triisopropylphosphine, tri-n-butylphosphine, triphenylphosphine, tributylphosphine, and quaternary phosphonium salts.
Examples of the basic ammonium compound include tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, trimethylethylammonium hydroxide, trimethylbenzylammonium hydroxide, trimethylphenylammonium hydroxide, Triethylmethylammonium hydroxide, triethylbenzylammonium hydroxide, triethylphenylammonium hydroxide, tributylbenzylammonium hydroxide, tributylphenylammonium hydroxide, tetraphenylammonium hydroxide, benzyltriphenylammonium hydroxide, methyltriphenylammonium hydroxide Sid, butyl triphenyl ammonium hydroxide, and the like.

  Examples of the amine compound include 4-aminopyridine, 2-aminopyridine, N, N-dimethyl-4-aminopyridine, 4-diethylaminopyridine, 2-hydroxypyridine, 2-methoxypyridine, 4-methoxypyridine, 2 -Dimethylaminoimidazole, 2-methoxyimidazole, imidazole, 2-mercaptoimidazole, 2-methylimidazole, aminoquinoline and the like.

  The amount of the catalyst used is usually 0.1 μmol to 300 μmol, preferably 0.5 μmol to 100 μmol, based on 1 mol of all dihydroxy compounds used, and among them, at least 1 selected from lithium and metals of Group 2 of the long-period periodic table When using a seed metal compound, the amount of metal is usually 0.1 μmol or more, preferably 0.5 μmol or more, particularly preferably 0.7 μmol or more, per 1 mol of all dihydroxy compounds used. Further, the upper limit is usually 20 μmol, preferably 10 μmol, more preferably 3 μmol, particularly preferably 1.5 μmol, and most preferably 1.0 μmol.

The catalyst may be added directly to the reactor, or may be added to a raw material adjusting tank in which the dihydroxy compound and the carbonic acid diester are mixed in advance and then exist in the reactor.
If the amount of the catalyst used is too small, sufficient polymerization activity cannot be obtained and the progress of the polymerization reaction is delayed, so that it is difficult to obtain a polycarbonate resin having a desired molecular weight, and the amount of raw material monomer incorporated into the polycarbonate resin is small. As a result, the amount of monomer distilling together with the monohydroxy compound produced as a by-product increases, resulting in deterioration of the raw material basic unit and the possibility of extra energy required for recovery. In the case of copolymerization using a dihydroxy compound, as described above, the composition ratio of the monomer used as a raw material and the constituent unit ratio derived from each monomer unit in the product polycarbonate resin may change. .

On the other hand, if the amount of the catalyst used is too large, the problems due to the excessive amount of monomer distilled as described above will be improved, but on the other hand, the hue, light resistance and heat stability of the obtained polycarbonate resin will be improved. There is a possibility that the sex etc. will deteriorate.
In addition, Group 1 metals, especially sodium, potassium and cesium, especially lithium, sodium, potassium and cesium, may have a bad influence on the hue when contained in the polycarbonate resin in a large amount. The total amount of these compounds in the polycarbonate resin is usually 1 ppm by weight or less, preferably 0.8 ppm by weight or less, more preferably, as the amount of metal. 0.7 ppm by weight or less.

The amount of metal in the polycarbonate resin can be measured using a method such as atomic emission, atomic absorption, or inductively coupled plasma (ICP) after recovering the metal in the polycarbonate resin by a method such as wet ashing.
In the present invention, by suppressing the volatilization of the monomer during the polymerization reaction, the molar ratio of the dihydroxy compound used as the raw material to the carbonic acid diester can be brought close to the theoretical amount of 1.00, thereby reducing the polymerization rate. A polycarbonate resin having a high molecular weight and good hue can be obtained.

(Polycarbonate resin obtained)
The polycarbonate resin obtained by the method of the present invention preferably has a light transmittance at a wavelength of 350 nm of a molded product (thickness 3 mm) molded from the resin of 60% or more, more preferably 65% or more, particularly preferably. Is 70% or more. When the light transmittance at the wavelength is less than 60%, the absorption increases and the light resistance may deteriorate.

In the polycarbonate resin of the present invention, the light transmittance at a wavelength of 320 nm of a molded body (thickness 3 mm flat plate) molded from the resin is preferably 30% or more, more preferably 40% or more, and 50 % Or more is particularly preferable. When the light transmittance at the wavelength is less than 30%, the light resistance tends to deteriorate.
The polycarbonate resin obtained by the method of the present invention is a radiation product having a wavelength of 300 nm to 400 nm using a metal halide lamp in a molded body (thickness 3 mm) molded from the resin in an environment of 63 ° C. and a relative humidity of 50%. It is preferable that the yellow index (YI) value based on ASTM D 1925-70 measured by transmitted light after irradiation treatment at an illuminance of 1.5 kW / m ² for 100 hours is 12 or less, more preferably 10 or less, particularly Preferably it is 8 or less.

In the present invention, the irradiation process using a metal halide lamp will be described later, but with a specific device, a specific filter or the like is used to mainly emit light with a wavelength of 300 nm to 400 nm (light with a wavelength other than this wavelength range). This means irradiating the sample for 100 hours with an irradiance of 1.5 kW / m ² .
In addition, the polycarbonate resin obtained by the method of the present invention is formed into a 3 mm-thick flat plate from the resin, and the yellow index value (measured with transmitted light) without performing irradiation treatment with the metal halide lamp as described above ( The initial yellow index value (referred to as the initial YI value) is usually 10 or less, preferably 7 or less, particularly preferably 5 or less, and the absolute value of the difference in yellow index before and after metal halide lamp irradiation is 6 or less. Is preferable, more preferably 4 or less, and particularly preferably 3 or less.

When the initial yellow index (YI) value exceeds 10, light resistance tends to deteriorate.
Furthermore, the polycarbonate resin obtained by the method of the present invention is molded into a 3 mm thick flat plate from the resin, and the L * value defined by the International Commission on Illumination (CIE) measured by transmitted light is usually 96.3. The above is preferably 96.6 or more, and preferably 96.8 or more. When the L * value is less than 96.3, the light resistance tends to deteriorate.

  In order to obtain such a polycarbonate resin, in addition to the features of the present invention as described above, for example, the type and amount of a catalyst that restricts the specific metal concentration during polymerization are appropriately selected, and the temperature during polymerization. In addition, the compound can be produced by appropriately selecting the time, reducing the compound that causes coloring, for example, reducing the residual monomer, residual phenol, and residual diphenyl carbonate, and reducing impurities that become the color of the raw material monomer to be used. In particular, the type and amount of the catalyst, the temperature and time during the polymerization are important.

The molecular weight of the polycarbonate resin obtained by the method of the present invention can be represented by a reduced viscosity, and the reduced viscosity is usually 0.30 dL / g or more, preferably 0.35 dL / g or more, and the upper limit of the reduced viscosity is 1.20 dL / g or less and 1.00 dL / g or less are more preferable, and 0.80 dL / g or less is still more preferable.
If the reduced viscosity of the polycarbonate resin is too low, the mechanical strength of the molded product may be small. If it is too large, the fluidity at the time of molding tends to decrease, and the productivity and moldability tend to decrease.

The reduced viscosity is measured using a Ubbelohde viscometer at a temperature of 20.0 ° C. ± 0.1 ° C., precisely prepared at a polycarbonate concentration of 0.6 g / dL using methylene chloride as a solvent.
The lower limit of the concentration of the terminal group represented by the following structural formula (5) of the polycarbonate resin obtained in the present invention is usually 20 μeq / g, preferably 40 μeq / g, particularly preferably 50 μeq / g, and the upper limit. Is usually 160 μeq / g, preferably 140 μeq / g, particularly preferably 100 μeq / g.

If the concentration of the end group represented by the following structural formula (5) is too high, even if the hue at the time of polymerization or at the time of molding is good, the hue after UV exposure may be deteriorated. Thermal stability may be reduced.
In order to control the concentration of the terminal group represented by the following structural formula (5), in addition to controlling the molar ratio of the dihydroxy compound containing the dihydroxy compound of the present invention and the diester carbonate, the polymerization pressure during the transesterification reaction And a method of controlling the polymerization temperature, the temperature of the reflux condenser, etc. according to the ease of volatilization of the monomer, and according to the present invention, it is possible to suppress the volatilization of the monomer. Control becomes easy.

The polycarbonate resin obtained by the method of the present invention is usually cooled and solidified after polycondensation as described above, and pelletized with a rotary cutter or the like.
The method of pelletization is not limited, but it is extracted from the final polymerization reactor in a molten state, cooled and solidified in the form of a strand, and pelletized, or from the final polymerization reactor in a molten state, uniaxial or biaxial extrusion. The resin is supplied to the machine, melt-extruded, cooled and solidified into pellets, or extracted from the final polymerization reactor in a molten state, cooled and solidified in the form of strands, once pelletized, and then uniaxially again Alternatively, a method may be mentioned in which resin is supplied to a biaxial extruder, melt-extruded, cooled and solidified, and pelletized.

At that time, in the extruder, the residual monomer under reduced pressure devolatilization, and generally known heat stabilizers, neutralizers, UV absorbers, mold release agents, colorants, antistatic agents, lubricants, lubricants, A plasticizer, a compatibilizer, a flame retardant, etc. can be added and kneaded.
The melt-kneading temperature in the extruder depends on the glass transition temperature and molecular weight of the polycarbonate resin, but is usually 150 to 300 ° C, preferably 200 to 270 ° C, more preferably 230 to 260 ° C. When the melt-kneading temperature is lower than 150 ° C., the melt viscosity of the polycarbonate resin is high, the load on the extruder is increased, and the productivity is lowered. When the temperature is higher than 300 ° C., the thermal deterioration of the polycarbonate becomes severe, resulting in a decrease in mechanical strength due to a decrease in molecular weight, coloring, and gas generation.

  In the production method of the present invention, it is desirable to install a filter in order to prevent foreign substances from entering. The filter installation position is preferably on the downstream side of the extruder, and the foreign matter removal size (opening) of the filter is preferably 100 μm or less as the filtration accuracy for 99% removal. In particular, in the case of disagreeing with the entry of minute foreign matters for film use etc., it is preferably 40 μm or less, more preferably 10 μm or less.

Also, the extrusion of polycarbonate resin is preferably carried out in a clean room having a higher degree of cleanliness than Class 7, more preferably Class 6 as defined in JIS B 9920 (2002), in order to prevent foreign matter from being mixed after extrusion. Is desirable.
Furthermore, when cooling the extruded polycarbonate resin into chips, it is preferable to use a cooling method such as air cooling or water cooling. As the air used for air cooling, it is desirable to use air from which foreign substances in the air have been removed in advance with a hepa filter or the like to prevent reattachment of foreign substances in the air.
When water cooling is used, it is desirable to use water from which metal in water has been removed with an ion exchange resin or the like, and foreign matter in water has been removed with a filter. The opening of the filter to be used is preferably 10 to 0.45 μm as 99% removal filtration accuracy.

The polycarbonate resin obtained by the method of the present invention can be formed into a molded product by a generally known method such as an injection molding method, an extrusion molding method, or a compression molding method.
Also, before performing various moldings, if necessary, the resin is heat stabilizer, neutralizer, UV absorber, mold release agent, colorant, antistatic agent, lubricant, lubricant, plasticizer, compatibilizing Additives such as additives and flame retardants can also be mixed with a tumbler, super mixer, floater, V-type blender, nauter mixer, Banbury mixer, extruder or the like.

  Polycarbonate resins obtained by the method of the present invention include, for example, aromatic polycarbonate, aromatic polyester, aliphatic polyester, polyamide, polystyrene, polyolefin, acrylic resin, amorphous polyolefin, ABS, AS, and other synthetic resins, polylactic acid, polybutylene. It can also be used as a polymer alloy by kneading with one or more of biodegradable resins such as succinate and rubber.

  According to the present invention, a polycarbonate resin excellent in light resistance, transparency, hue, heat resistance, thermal stability, and mechanical strength and having stable performance can be efficiently produced with reduced monomer loss.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited by a following example, unless the summary is exceeded.
In the following, the physical properties and characteristics of polycarbonate were evaluated by the following methods.
(1) Measurement of oxygen concentration
The oxygen concentration in the polymerization reaction apparatus was measured using an oxygen meter (manufactured by AMI: 1000RS).

(2) Quantification of amount of distilled monomer and amount of phenol The weight of each monomer and phenol distilled at each reaction stage was quantified from the composition measured by liquid chromatography.
(3) Calculation of the ratio (% by weight) of the total amount of distilled monomers to the total amount of raw material monomers The total amount of all distilled monomers including diphenyl carbonate, as determined in (2) above, was charged as a raw material. From the total amount of all monomers, the ratio of the total amount of distilled monomers to the total amount of raw material monomers was calculated.

(4) Measurement of reduced viscosity A polycarbonate resin sample was dissolved using methylene chloride as a solvent to prepare a polycarbonate solution having a concentration of 0.6 g / dL. Measured at a temperature of 20.0 ° C. ± 0.1 ° C. using an Ubbelohde viscometer manufactured by Moriyu Rika Kogyo Co., Ltd., and obtained the relative viscosity ηrel from the following equation from the solvent passage time t ₀ and the solution passage time t
ηrel = t / t ₀
From the relative viscosity, the specific viscosity ηsp was determined from the following formula.

ηsp = (η−η ₀ ) / η ₀ = ηrel−1
The reduced viscosity ηsp / c was determined by dividing the specific viscosity by the concentration c (g / dL). The higher this value, the higher the molecular weight.
(5) Measurement of the structural unit ratio derived from each dihydroxy compound in the polycarbonate resin and the terminal phenyl group concentration The ratio of each dihydroxy compound structural unit in the polycarbonate resin was obtained by weighing out 30 mg of the polycarbonate resin to about 0.7 mL of deuterated chloroform. dissolved, a solution, which was placed in a NMR tube having an inner diameter of 5 mm, was analyzed by ¹ H NMR spectrum at room temperature using a Nippon Denshi JNM-AL400 (resonance frequency 400 MHz). The structural unit ratio derived from each dihydroxy compound was determined from the signal intensity ratio based on the structural unit derived from each dihydroxy compound.

The terminal phenyl group concentration was determined from the signal intensity ratio based on the internal standard and the terminal phenyl group by measuring ¹ H-NMR in the same manner as described above using 1,1,2,2-tetrabromoethane as the internal standard.
(6) Deviation between the composition ratio of each dihydroxy compound charged as a raw material and the structural unit ratio derived from each dihydroxy compound in the resulting polycarbonate resin The mole percentage of the dihydroxy compound structural unit in the polycarbonate resin determined in (5) above And the absolute value of the value obtained by dividing the difference in mole percentage of the dihydroxy compound charged as the raw material by the mole percentage of the dihydroxy compound charged as the raw material. The larger the value, the greater the deviation.

(7) Measurement of metal concentration in polycarbonate resin About 0.5 g of polycarbonate resin pellets are precisely weighed in a microwave decomposition vessel manufactured by PerkinElmer, and 2 mL of 97% sulfuric acid is added to make it sealed and microwave at 230 ° C. for 10 minutes. Heated. After cooling to room temperature, 1.5 mL of 68% nitric acid is added, sealed and microwave heated at 150 ° C. for 10 minutes, cooled again to room temperature, added with 2.5 mL of 68% nitric acid, and sealed again. And microwaved at 230 ° C. for 10 minutes to completely decompose the contents. After cooling to room temperature, the liquid obtained above was diluted with pure water and quantified with ICP-MS manufactured by ThermoQuest.

(8) Evaluation Method of Initial Hue of Polycarbonate Resin Pellets of polycarbonate resin are dried at 110 ° C. for 10 hours in a nitrogen atmosphere. Next, the dried polycarbonate resin pellets were supplied to an injection molding machine (J75EII type, manufactured by Nippon Steel Co., Ltd.), and injection molded pieces (width 60 mm × length 60 mm × under conditions of a resin temperature of 220 ° C. and a molding cycle of 23 seconds) Repeat the operation to form a 3mm thick) color tester (Konica Minolta, Inc.) using the yellow index (YI) value and L * value in the transmitted light in the thickness direction of the injection molded pieces obtained in the 10th to 20th shots. An average value was calculated using CM-3700d). The smaller the YI value, the better the quality without yellowness, and the larger the L * value, the higher the brightness.

(9) Light transmittance at wavelengths of 350 nm and 320 nm The light transmittance in the thickness direction of the injection molded piece (width 60 mm × length 60 mm × thickness 3 mm, 10th shot to 20th shot) obtained in (8) above. The measurement was performed using an ultraviolet-visible spectrophotometer (U2900 manufactured by Hitachi High-Technologies Corporation), and the average value was calculated and evaluated.
(10) Metal halide lamp irradiation test Using a metal ring weather meter M6T manufactured by Suga Test Instruments Co., Ltd., a horizontal metal ring lamp as a light source, quartz as an inner filter, and quartz A # 500 filter is attached around as an outer filter, the irradiance at a wavelength of 300 to 400 nm is set to 1.5 kw / m2, and the 20th shot flat plate obtained in (8) above (width 60 mm × length) A square surface having a thickness of 60 mm × thickness of 3 mm was subjected to irradiation treatment for 100 hours. The YI value after irradiation was measured in the same manner as (8) above.

The abbreviations of the compounds used in the description of the following examples are as follows.
ISB: Isosorbide (Rocket Fleure, trade name POLYSORB)
CHDM: 1,4-cyclohexanedimethanol (trade name SKY CHDM manufactured by Shin Nippon Rika Co., Ltd.)
DEG: Diethylene glycol (Mitsubishi Chemical Corporation)
DPC: Diphenyl carbonate (Mitsubishi Chemical Corporation)
[Example 1]
(First stage reaction)
A 40L polymerization reactor equipped with a heat medium jacket and a stirring blade using oil as a heat medium, and a distillation pipe connected to a vacuum pump was subjected to distillation purification by 30.44 mol of ISB, 13.04 mol of CHDM, and chloride. After 43.48 mol of DPC having an ion concentration of 10 ppb or less was charged and calcium acetate monohydrate made into an aqueous solution was charged to 1.25 × 10 ⁻⁶ mol per 1 mol of all dihydroxy compounds, nitrogen substitution was sufficiently performed. (Oxygen concentration 0.0005 vol% to 0.001 vol%). A reflux condenser using steam (inlet temperature 100 ° C.) as a refrigerant and a condenser using hot water (inlet temperature 45 ° C.) as a refrigerant were arranged downstream of the reflux condenser in the distillation pipe. Subsequently, a heated heating medium is circulated through the reactor, and stirring is started when the reaction solution (that is, the internal temperature) reaches 100 ° C., and the contents are melted and uniformly distributed while maintaining the internal temperature at 100 ° C. did. Thereafter, the temperature rise is started, the internal temperature is set to 220 ° C. in 40 minutes, the pressure reduction is started when the internal temperature reaches 220 ° C., and 13.3 kPa (absolute pressure, the same applies hereinafter) in 90 minutes. Was controlled as follows. When depressurization is started, the temperature of the oil introduced into the heat medium jacket (heat medium jacket inlet temperature) is appropriately adjusted so that the vapor of phenol generated by the reaction starts to distill and the internal temperature is controlled to be constant at 220 ° C. It was adjusted. During the time period when the amount of phenol distillate increased, the temperature of the heat medium oil was set at 242 ° C., and other time periods were set at less than 242 ° C.

After reaching 13.3 kPa, the pressure was maintained and maintained for an additional 60 minutes to obtain a polycarbonate oligomer.
Phenol and by-produced monomer produced as a by-product in the polymerization reaction are partly condensed in a reflux condenser and returned to the polymerization reactor, and uncondensed phenol and monomer not condensed in the reflux condenser are led to the condenser. It was collected. The phenol distilled at this stage was 94% of the theoretical distillation amount.

(Second stage reaction)
The polycarbonate oligomer obtained in the first stage was transferred to a polymerization reactor equipped with a heat medium jacket using oil as a heat medium, a stirring blade, and a distillation pipe connected to a vacuum pump under a nitrogen atmosphere. In the distillation pipe, a reflux condenser using steam (inlet temperature 100 ° C.) as a refrigerant, a condenser using hot water (inlet temperature 45 ° C.) as a refrigerant downstream of the reflux condenser, and further downstream of dry ice A cold trap was installed with the refrigerant.

  After transferring the oligomer, decompression was started, and the internal temperature was 220 ° C. and the pressure was 200 Pa in 60 minutes. Thereafter, the internal temperature was set to 230 ° C. over 20 minutes, the pressure was 133 Pa or less, the pressure was restored when the predetermined stirring power was reached, the contents were extracted in the form of strands, and pelletized with a rotary cutter. At this time, the time from the time when the pressure reached 1 kPa to the time when the predetermined stirring power was reached was measured.

Phenol and by-produced monomer produced as a by-product in the polymerization reaction are partly condensed in a reflux condenser and returned to the polymerization reactor, and uncondensed phenol and monomer not condensed in the reflux condenser are led to the condenser. It was collected. Further, the distillate that was not condensed by the condenser was collected by a cold trap installed downstream of the condenser.
At each reaction stage, the distillate collected by a reflux condenser, a condenser, and a cold trap was measured for weight and composition, respectively, and the by-produced phenol and monomer were quantified. Table 1 shows the total weight of the distilled monomer in each stage determined in this way, and the ratio with the monomer charged as a raw material was calculated.

The obtained pellets were extruded in a strand shape using a twin screw extruder (LABOTEX30HSS-32) manufactured by Nippon Steel Works with two vents so that the resin temperature at the outlet was 250 ° C, and cooled and solidified with water. Then, it was pelletized with a rotary cutter. At this time, the vent port was connected to a vacuum pump, and the pressure at the vent port was controlled to be 500 Pa.
Table 1 shows the analysis results of the obtained polycarbonate resin and the results evaluated in the above method. Distillation of monomer is small, and there is little deviation between the ratio of dihydroxy compound charged as a raw material and the ratio of dihydroxy compound structural unit in the obtained polycarbonate resin, resulting in a polycarbonate resin with good yellowness, lightness, and good color tone. The light resistance was also good.

[Example 2]
The same procedure as in Example 1 was conducted except that the molar ratio of ISB and CHDM and the maximum temperature of the heat medium in the first stage reaction were changed. Similar to Example 1, the amount of monomer distilling is small, the deviation of the ratio of the dihydroxy compound charged as a raw material and the ratio of the dihydroxy compound structural unit in the obtained polycarbonate resin is small, the yellowness is small, the lightness is excellent, and the color tone A good polycarbonate resin was obtained, and the light resistance was also good.

[Example 3]
Example 1 except that calcium acetate monohydrate was charged to 2.50 × 10 ⁻⁶ mol per mol of all dihydroxy compounds, and the maximum temperature of the heat medium in the first stage reaction was 244 ° C. It carried out similarly. Similar to Example 1, the amount of monomer distilling is small, the deviation of the ratio of the dihydroxy compound charged as a raw material and the ratio of the dihydroxy compound structural unit in the obtained polycarbonate resin is small, the yellowness is small, the lightness is excellent, and the color tone A good polycarbonate resin was obtained, and the light resistance was also good.

[Example 4]
Calcium acetate monohydrate was charged in an amount of 0.90 × 10 ⁻⁶ mol per 1 mol of all dihydroxy compounds, and the maximum temperature of the heat medium in the first stage reaction was changed to 239 ° C. It carried out similarly. As in Example 1, a polycarbonate resin was obtained in which the amount of distillate of the monomer was small and the difference between the ratio of the dihydroxy compound charged as a raw material and the ratio of the dihydroxy compound structural unit in the obtained polycarbonate resin was small. Moreover, yellowness was smaller than Example 1, the brightness was excellent, and the light resistance was also favorable.

[Example 5]
Example 1 except that calcium acetate monohydrate was charged to 0.25 × 10 ⁻⁶ mol per 1 mol of all dihydroxy compounds and the maximum temperature of the heat medium in the first stage reaction was 233 ° C. It carried out like. Compared to Example 1, the polymerization rate in the second stage was decreased and the distillation of the monomer was slightly increased, but a polycarbonate resin having a small yellowness, excellent lightness, and good color tone was obtained, and light resistance was also good. there were.

[Example 6]
This was carried out in the same manner as in Example 3 except that magnesium acetate tetrahydrate was used instead of calcium acetate monohydrate and the maximum temperature of the heat medium in the first stage reaction was changed. As in Example 3, the amount of distillate of the monomer is small, the difference between the ratio of the dihydroxy compound charged as a raw material and the ratio of the dihydroxy compound structural unit in the obtained polycarbonate resin is small, the yellowness is small, the lightness is excellent, and the color tone A good polycarbonate resin was obtained, and the light resistance was also good.

[Example 7]
The same procedure as in Example 3 was performed except that barium acetate was used instead of calcium acetate monohydrate and the maximum temperature of the heat medium in the first stage reaction was changed. As in Example 3, the amount of distillate of the monomer is small, the difference between the ratio of the dihydroxy compound charged as a raw material and the ratio of the dihydroxy compound structural unit in the obtained polycarbonate resin is small, the yellowness is small, the lightness is excellent, and the color tone A good polycarbonate resin was obtained, and the light resistance was also good.

[Example 8]
The same procedure as in Example 3 was performed except that lithium acetate was used instead of calcium acetate monohydrate and the maximum temperature of the heating medium in the first stage reaction was changed. As in Example 3, the amount of distillate of the monomer is small, the difference between the ratio of the dihydroxy compound charged as a raw material and the ratio of the dihydroxy compound structural unit in the obtained polycarbonate resin is small, the yellowness is small, the lightness is excellent, and the color tone A good polycarbonate resin was obtained, and the light resistance was also good.

[Example 9]
The same procedure as in Example 3 was performed except that DEG was used instead of CHDM and the maximum temperature of the heat medium in the first stage reaction was changed. As in Example 3, the amount of distillate of the monomer is small, the difference between the ratio of the dihydroxy compound charged as a raw material and the ratio of the dihydroxy compound structural unit in the obtained polycarbonate resin is small, the yellowness is small, the lightness is excellent, and the color tone A good polycarbonate resin was obtained, and the light resistance was also good.

[Example 10]
The same procedure as in Example 3 was performed except that cesium carbonate was used instead of calcium acetate monohydrate and the maximum temperature of the heat medium in the first stage reaction was changed. Compared with Example 3, the distillation of the monomer was slightly increased, the polymerization time was increased, and the deviation between the ratio of the dihydroxy compound charged as a raw material and the ratio of the dihydroxy compound structural unit in the obtained polycarbonate resin was also slightly increased. .

[Example 11]
Example 1 except that calcium acetate monohydrate was charged to 5.00 × 10 ⁻⁶ mol per 1 mol of all dihydroxy compounds and the maximum temperature of the heating medium in the first stage reaction was changed to 248 ° C. 1 was carried out. As in Example 1, the difference between the ratio of the dihydroxy compound charged as a raw material and the ratio of the dihydroxy compound structural unit in the obtained polycarbonate resin was small, but slight coloring was observed.

[Comparative Example 1]
The same procedure as in Example 10 was performed except that the reflux condenser was bypassed and not used in the first stage and the second stage. In the second stage, the predetermined power was not reached even after 180 minutes had passed since reaching 1 kPa, so the polymer was extracted there. The amount of monomer distillation was large, and not only the difference between the ratio of the dihydroxy compound charged as a raw material and the ratio of the dihydroxy compound structural unit in the obtained polycarbonate resin was large, but also the yellowness and light resistance deteriorated.

[Comparative Example 2]
In the first stage, after the raw material mixture is uniformly melted at 100 ° C., the internal temperature is set to 220 ° C. over 60 minutes, and when the internal temperature reaches 220 ° C., decompression is started, and in 13 minutes, 13. It implemented similarly to the comparative example 1 except having controlled so that it might be set to 3 kPa.
In the second stage, the predetermined power was not reached even after 180 minutes had passed since reaching 1 kPa, so the polymer was extracted there. Although the amount of monomer distillate decreased from Comparative Example 1, it was still large, and the difference between the ratio of dihydroxy compound charged as a raw material and the ratio of structural units of dihydroxy compound in the obtained polycarbonate resin was large.

[Comparative Example 3]
In the first stage reaction, after the raw material mixture was uniformly melted at 100 ° C., the internal temperature was increased to 250 ° C. over 40 minutes, and when the internal temperature reached 250 ° C., decompression was started, and 90 minutes Control was performed to 13.3 kPa, and the same procedure as in Comparative Example 1 was performed except that the maximum temperature of the heat medium in the first stage reaction was 275 ° C. In the second stage, the predetermined power was not reached even after 180 minutes had passed since reaching 1 kPa, so the polymer was extracted there. There was a large amount of monomer distillate, and the difference between the ratio of the dihydroxy compound charged as a raw material and the ratio of the dihydroxy compound structural unit in the obtained polycarbonate resin was large. Further, the viscosity was low and molding could not be performed.

[Reference example]
(First stage reaction)
0.5B mol of ISB and 0.227 mol of CHDM were distilled into a 0.5L glass polymerization reactor equipped with a stirring blade and a distillation pipe connected to a vacuum pump, and the chloride ion concentration was 10ppb or less by distillation purification. Then, 0.773 mol of DPC was charged and calcium acetate monohydrate made into an aqueous solution was charged to 1.25 × 10 ⁻⁶ mol per 1 mol of all dihydroxy compounds, and then sufficiently substituted with nitrogen. Subsequently, the reactor is immersed in an oil bath, and stirring is started when the reaction solution (sometimes referred to as the internal temperature) reaches 100 ° C., and the contents are melted uniformly while maintaining the internal temperature at 100 ° C. I made it. Thereafter, the temperature increase was started, the internal temperature was set to 220 ° C. in 40 minutes, the pressure reduction was started when the internal temperature reached 220 ° C., and the pressure was controlled to 13.3 kPa in 90 minutes. When depressurization was started, the vapor of phenol generated by the reaction immediately started to distill, and the temperature of the oil bath was appropriately adjusted so that the internal temperature was controlled to be constant at 220 ° C. The oil bath temperature was 224 ° C. during the time when the amount of phenol distillate increased, and the other time zone was less than 224.

After reaching 13.3 kPa, the pressure was maintained and maintained for an additional 60 minutes to obtain a polycarbonate oligomer.
The phenol produced as a by-product in the polymerization reaction and the monomer distilled off were led to a condenser (refrigerant inlet temperature: 45 ° C.) and recovered. Phenol distilled at this stage was 90% of theoretical distillation.

(Second stage reaction)
Then, while raising the temperature of the oil bath, pressure reduction was started and the internal temperature was set to 220 ° C. and the pressure was set to 200 Pa in 60 minutes. Thereafter, the internal temperature was set to 230 ° C. and the pressure was 133 Pa or less over 20 minutes, and when the predetermined stirring power was reached, the pressure was restored and the contents were extracted in the form of strands. At this time, the time from the time when the pressure reached 1 kPa to the time when the predetermined stirring power was reached was measured. The phenol produced as a by-product in the polymerization reaction and the monomer to be distilled are led to a condenser (refrigerant inlet temperature: 45 ° C.) and recovered in the same manner as in the first stage reaction, and the distillate not condensed in the condenser is It was recovered with a cold trap installed downstream of the condenser.

  At each reaction stage, the distillate collected by a reflux condenser, a condenser, and a cold trap was measured for weight and composition, respectively, and the by-produced phenol and monomer were quantified. Table 1 shows the total weight of the distilled monomer in each stage determined in this way, and the ratio with the monomer charged as a raw material was calculated.

  According to the method for producing a polycarbonate resin of the present invention, a polycarbonate resin having excellent light resistance, transparency, hue, heat resistance, thermal stability, mechanical strength and stable performance is produced efficiently and stably. It is possible.

Claims (12)

A method for producing a polycarbonate resin by polycondensation by transesterification in a plurality of reactors using a carbonic acid diester and a dihydroxy compound as raw materials and a catalyst in multiple stages,
Are those carbonic acid diester is purified by distillation, dihydroxy having di-hydroxy compound, a plurality of kinds of dihydroxy compound, a portion which at least one of them is represented by the following general formula (1) in a part of the structure A compound,
At least one of the reactors has a distillation amount of a monohydroxy compound by-produced by the transesterification reaction of 20% or more of the theoretical distillation amount, and a heating means and a reflux for heating the reactor using a heat medium what internal volume 20L more reactors der provided with the condenser, the temperature difference of the reaction solution in the reactor in the temperature of the heat medium is at least 5 ° C. or more,
The difference between the molar percentage of the dihydroxy compound at the time of charging as a raw material and the molar percentage of the structural unit of the dihydroxy compound in the obtained polycarbonate resin is determined as the mole of the dihydroxy compound at the time of charging as the raw material. A method for producing a polycarbonate resin, characterized in that the absolute value of the value divided by percentage is 0.03 or less for at least one dihydroxy compound, and does not exceed 0.05 for any dihydroxy compound.

(However, the site represented by the above general formula (1) unless it is part of _-CH 2 -O-H.) The method for producing a polycarbonate resin according to claim 1, wherein the total amount of monomers distilled out in all reaction steps is 10% by weight or less based on the total amount of raw material monomers. The method for producing a polycarbonate resin according to claim 1 or 2, wherein a boiling point at atmospheric pressure of at least one of the dihydroxy compounds is 300 ° C or lower.   The method for producing a polycarbonate resin according to any one of claims 1 to 3, wherein at least three reactors are used.   The method for producing a polycarbonate resin according to any one of claims 1 to 4, wherein a temperature of the refrigerant introduced into the reflux condenser is 45 to 180 ° C at an inlet of the reflux condenser.   The method for producing a polycarbonate resin according to any one of claims 1 to 5, wherein a total amount of monomers distilled out in all the reaction steps is 3% by weight or less based on a total amount of raw material monomers.   In the first reactor in which the amount of monohydroxy compound produced as a by-product by the transesterification distills 20% or more of the theoretical amount of distillate, lithium and a metal of Group 2 of the long-period periodic table are used as a catalyst. 7. The polycarbonate resin according to claim 1, wherein at least one metal compound selected from the group consisting of 20 μmol or less is used as a total amount of the metal atoms per 1 mol of all dihydroxy compounds used as a raw material. Manufacturing method.   The method for producing a polycarbonate resin according to claim 7, wherein the catalyst is at least one metal compound selected from the group consisting of a magnesium compound and a calcium compound.   The method for producing a polycarbonate resin according to any one of claims 1 to 8, wherein the maximum temperature of the reaction liquid in all reaction stages is less than 250 ° C.   The method for producing a polycarbonate resin according to any one of claims 1 to 9, wherein the maximum temperature of the heat medium is less than 265 ° C. 11. The method according to claim 1, wherein the dihydroxy compound includes a compound represented by the following general formula (2) and at least one compound selected from the group consisting of an aliphatic dihydroxy compound and an alicyclic dihydroxy compound. The manufacturing method of polycarbonate resin of description.

The method for producing a polycarbonate resin according to any one of claims 1 to 10, wherein a chloride ion concentration in the carbonic acid diester is 10 ppb or less.