JP5939012B2 - Method for producing polycarbonate resin - Google Patents

Description

  The present invention provides a method for efficiently and stably producing a polycarbonate resin that is excellent in optical properties, hue, thermal stability, and the like and has few foreign matters, and a polycarbonate pellet obtained by the production method.

  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 plastic.

  Recently, a copolymer polycarbonate resin derived from a dihydroxy compound having a fluorene structure in the side chain has been reported. Particularly, a copolymer polycarbonate resin with an aliphatic dihydroxy compound has excellent optical properties such as a small photoelastic coefficient. (Patent Documents 1 to 3). Among them, Patent Document 3 discloses that a retardation film made of a polycarbonate resin containing a fluorene structure has a low photoelastic coefficient and a reverse wavelength dispersion that becomes smaller as the retardation becomes shorter. It is disclosed that it is useful for optical applications such as films.

When the copolymer polycarbonate resin using the dihydroxy compound having the fluorene structure is produced, it is produced by a method called a transesterification method or a melting method in which various dihydroxy compounds can be used as raw materials. In this method, a dihydroxy compound and a carbonic acid diester such as diphenyl carbonate are transesterified at a high temperature of 200 ° C. or higher in the presence of a polymerization catalyst to remove the by-produced phenol out of the system to obtain a polycarbonate resin. Therefore, there has been a problem that the resin is colored due to thermal decomposition during the polycondensation reaction performed at a high temperature.
In order to solve this problem, a method of improving the color tone of a polymer obtained by performing a polymerization reaction with a smaller thermal history using a continuous polymerization process has been proposed (see Patent Document 4).

Further, when the polycarbonate resin after the reaction is subjected to a treatment such as pelletization under heating, there is a problem that the resin is colored due to thermal decomposition of the polymer.
One way to solve this problem is to use a continuous reaction process that continuously feeds the reactor and removes the polycarbonate resin produced at the same time. Is used to reduce the amount of the aromatic monohydroxy compound remaining in the polymer to 1000 ppm or less and to improve the color tone of the resulting polymer (see Patent Document 5). .

JP-A-10-101786 JP 2004-67990 A International Publication No. 2006/41190 Pamphlet JP 2009-161745 A JP 2007-70392 A

  In a continuous polymerization process, piping connecting a plurality of reactors is required, but due to the study by the present inventors, the heat history in the piping of the reaction solution greatly affects the color tone of the obtained polycarbonate resin. It was found. Furthermore, a problem has also been found in which the polycarbonate resin melted after the final polymerization reactor stays in the pipe, whereby the polymerization reaction and thermal decomposition proceed, and the residual low molecular components in the resin increase.

  Furthermore, in the continuous polymerization process, the molten polycarbonate resin coming out of the reactor is passed through an extruder as it is, and a thermal stabilizer such as an antioxidant or a release agent is added, or it is passed through a filter. In addition, there is an advantage that foreign substances contained in the resin can be removed by filtration. However, in the extruder, the temperature of the resin rises due to shearing heat generation, and high viscosity molten resin is filtered by a filter. It has been clarified that a temperature higher than the polymerization temperature is required, which causes coloring of the resin.

  Since the resin used for optical applications is required to have particularly high transparency and less contamination of foreign substances, the present invention solves the above-mentioned problems and contains a fluorene structure that is suitably used for optical applications. An object of the present invention is to provide a method for producing a polycarbonate resin.

Ｔ_i：配管ｉの入口における反応液又は溶融ポリカーボネート樹脂の温度と、出口
における反応液又は溶融ポリカーボネート樹脂の温度のいずれか高い方の温度［Ｋ］
θ_i：配管ｉにおける滞留時間［ｍｉｎ］
［２］最終重合反応器の出口からポリカーボネート樹脂を取り出すまでの滞留時間が３０分以内である［１］に記載のポリカーボネート樹脂の製造方法。
［３］生成するモノヒドロキシ化合物が６ｗｔ％以上含有される反応液を移送する場合は配管中の反応液温度を２１０℃以下とし、３ｗｔ％以上６ｗｔ％未満含有される反応液を移送する場合は配管中の反応液温度を２２０℃以下とし、１ｗｔ％以上３ｗｔ％未満含有される反応液を移送する場合は配管中の反応液温度を２３０℃以下とする［１］又は［２］に記載のポリカーボネート樹脂の製造方法。
［４］最終重合反応器出口におけるポリカーボネート樹脂中のモノヒドロキシ化合物の量をＡ［ｐｐｍ］、得られるポリカーボネート樹脂中のモノヒドロキシ化合物の含有量をＢ［ｐｐｍ］とした場合に、下記式（６）を満たす［１］乃至［３］のいずれかに記載のポリカーボネート樹脂の製造方法。
Ａ−Ｂ ≧ １００ （６）
［５］前記重合触媒が、長周期型周期表第２族の金属及びリチウムからなる群より選ばれる少なくとも１種の金属化合物である［１］乃至［４］のいずれかに記載のポリカーボネート樹脂の製造方法。
［６］前記ジヒドロキシ化合物（Ａ）が、下記構造式（１１）で表されるジヒドロキシ化合物である［１］乃至［５］のいずれかに記載のポリカーボネート樹脂の製造方法。

（上記一般式（１１）中、Ｒ¹〜Ｒ⁴はそれぞれ独立に、水素原子、置換若しくは無置換の炭素数１〜炭素数２０のアルキル基、置換若しくは無置換の炭素数６〜炭素数２０のシクロアルキル基、または、置換若しくは無置換の炭素数６〜炭素数２０のアリール基を表し、Ｘは置換若しくは無置換の炭素数２〜炭素数１０のアルキレン基、置換若しくは無置換の炭素数６〜炭素数２０のシクロアルキレン基、または、置換若しくは無置換の炭素数６〜炭素数２０のアリーレン基を表す。ｍ及びｎはそれぞれ独立に０〜５の整数である。）［７］少なくとも前記ジヒドロキシ化合物（Ａ）と、下記式（１２）で表される部位を有
する１種または複数種のジヒドロキシ化合物（Ｂ）とを原料として用いる［１］乃至［６］のいずれかに記載のポリカーボネート樹脂の製造方法。

（但し、上記式（１２）で表される部位が−ＣＨ₂−ＯＨの一部を構成する部位である場
合と、ジヒドロキシ化合物（Ｂ）が前記（１１）式で表される化合物である場合を除く。）
［８］前記ジヒドロキシ化合物（Ｂ）が、環状エーテル構造を有する化合物である［７］に記載のポリカーボネート樹脂の製造方法。
［９］前記ジヒドロキシ化合物（Ｂ）は、下記構造式（１３）で表される化合物である［８］に記載のポリカーボネート樹脂の製造方法。

［１０］得られるポリカーボネート樹脂が、温度２４０℃、剪断速度９１．２ｓｅｃ^-1における溶融粘度が１０００Ｐａ・ｓ以上、４０００Ｐａ・ｓ以下である［１］乃至［９］のいずれかに記載のポリカーボネート樹脂の製造方法。
［１１］前記重縮合により得られた前記ポリカーボネート樹脂を、固化させることなく溶融状態のまま押出機に供給する工程を含む［１］乃至［１０］のいずれかに記載のポリカーボネート樹脂の製造方法。
［１２］前記重縮合により得られた前記ポリカーボネート樹脂を、固化させることなく溶融状態のままフィルターに供給して濾過する工程を含む［１］乃至［１１］のいずれかに記載のポリカーボネート樹脂の製造方法。
［１３］重縮合により得られたポリカーボネート樹脂、又は、溶融状態でフィルターにより濾過したポリカーボネート樹脂を、ダイスヘッドからストランドの形態で吐出し、冷却後、カッターを用いてペレット化する工程を含む［１］乃至［１２］のいずれかに記載のポリカーボネート樹脂の製造方法。
［１４］［１３］に記載の方法により製造されたポリカーボネートペレット。
［１５］厚さ３５μｍ±５μｍのフィルムに成形したとき、該フィルムに含まれる最大長２５μｍ以上の異物が１０００個／ｍ²以下である［１４］に記載のポリカーボネートペ
レット。 As a result of intensive investigations by the present inventors to solve the above problems, in the method for producing a polycarbonate resin by polycondensation of a dihydroxy compound and a carbonic acid diester, the temperature of the reaction liquid in the transfer pipe or the temperature of the molten polycarbonate resin By setting the parameter related to the heat history represented by the residence time within the specified range, the amount of foreign matter is at a level that does not cause a problem in practice, but it excels in transparency, hue, heat resistance, thermal stability, mechanical strength, etc. The present inventors have found that the polycarbonate resin can be produced efficiently and stably, and have completed the present invention. That is, the gist of the present invention resides in the following [1] to [15].
[1] A method for producing a polycarbonate resin by continuously supplying a dihydroxy compound containing a dihydroxy compound (A) having a fluorene structure (A), a carbonic acid diester, and a polymerization catalyst to a reactor and performing polycondensation, At least a plurality of reactors are connected in series, and a reaction solution or melt in each pipe between the first reactor among the reactors connected to the plurality of reactors and the step of taking out the polycarbonate resin. and the residence time of the polycarbonate resin, the production method of the polycarbonate resin temperature defined by T _i satisfies the following formula (1) in each pipe.

T _i : Temperature [K], whichever is the higher of the temperature of the reaction liquid or molten polycarbonate resin at the inlet of the pipe i and the temperature of the reaction liquid or molten polycarbonate resin at the outlet
θ _i : Residence time in pipe i [min]
[2] The method for producing a polycarbonate resin according to [1], wherein the residence time until the polycarbonate resin is taken out from the outlet of the final polymerization reactor is within 30 minutes.
[3] When transferring a reaction solution containing 6 wt% or more of the produced monohydroxy compound, the reaction solution temperature in the pipe is 210 ° C. or less, and when transferring a reaction solution containing 3 wt% or more and less than 6 wt% When the reaction liquid temperature in the piping is set to 220 ° C. or lower and the reaction liquid contained in the piping at 1 wt% or more and less than 3 wt% is transferred, the reaction liquid temperature in the piping is set to 230 ° C. or lower as described in [1] or [2] A method for producing a polycarbonate resin.
[4] When the amount of the monohydroxy compound in the polycarbonate resin at the outlet of the final polymerization reactor is A [ppm] and the content of the monohydroxy compound in the obtained polycarbonate resin is B [ppm], the following formula (6 The method for producing a polycarbonate resin according to any one of [1] to [3].
A-B ≧ 100 (6)
[5] The polycarbonate resin according to any one of [1] to [4], wherein the polymerization catalyst is at least one metal compound selected from the group consisting of a metal of Group 2 of the long-period periodic table and lithium. Production method.
[6] The method for producing a polycarbonate resin according to any one of [1] to [5], wherein the dihydroxy compound (A) is a dihydroxy compound represented by the following structural formula (11).

(In the general formula (11), R ^{1 to} R ⁴ are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted carbon number 6 to 20 carbon atoms. Or a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, X is a substituted or unsubstituted alkylene group having 2 to 10 carbon atoms, substituted or unsubstituted carbon number Represents a cycloalkylene group having 6 to 20 carbon atoms, or a substituted or unsubstituted arylene group having 6 to 20 carbon atoms, m and n are each independently an integer of 0 to 5.) [7] At least The poly according to any one of [1] to [6], wherein the dihydroxy compound (A) and one or more dihydroxy compounds (B) having a site represented by the following formula (12) are used as raw materials. Method of manufacturing a Boneto resin.

(However, in the case moiety represented by the above formula (12) is a portion constituting a part of -CH ₂ -OH, if the dihydroxy compound (B) is the (11) compound represented by the formula except for.)
[8] The method for producing a polycarbonate resin according to [7], wherein the dihydroxy compound (B) is a compound having a cyclic ether structure.
[9] The method for producing a polycarbonate resin according to [8], wherein the dihydroxy compound (B) is a compound represented by the following structural formula (13).

[10] The polycarbonate resin according to any one of [1] to [9], wherein the obtained polycarbonate resin has a melt viscosity of 1000 Pa · s to 4000 Pa · s at a temperature of 240 ° C. and a shear rate of 91.2 sec ⁻¹ . Manufacturing method.
[11] The method for producing a polycarbonate resin according to any one of [1] to [10], including a step of supplying the polycarbonate resin obtained by the polycondensation to an extruder in a molten state without solidifying.
[12] The production of the polycarbonate resin according to any one of [1] to [11], which includes a step of supplying the polycarbonate resin obtained by the polycondensation to a filter in a molten state without solidification and filtering. Method.
[13] A step of discharging a polycarbonate resin obtained by polycondensation or a polycarbonate resin filtered through a filter in a molten state from a die head in the form of a strand, cooling, and pelletizing using a cutter [1] ] The manufacturing method of the polycarbonate resin in any one of [12].
[14] Polycarbonate pellets produced by the method according to [13].
[15] The polycarbonate pellet according to [14], wherein when formed into a film having a thickness of 35 μm ± 5 μm, foreign matter having a maximum length of 25 μm or more contained in the film is 1000 / m ² or less.

It is a figure which shows an example of the manufacturing apparatus which concerns on the manufacturing method of polycarbonate resin of this invention.

  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. In addition, in this specification, when the expression “to” is used, it is used in a sense including numerical values or physical values before and after that.

Ｔ_i：配管ｉの入口における反応液又は溶融カーボネート樹脂の温度と、出口にお
ける反応液又は溶融ポリカーボネート樹脂の温度のいずれか高い方の温度［Ｋ］
θ_i：配管ｉにおける滞留時間［ｍｉｎ］ In the method for producing a polycarbonate resin of the present invention, a dihydroxy compound containing a dihydroxy compound (A) having a fluorene structure, a carbonic acid diester, and a polymerization catalyst are continuously supplied to a reactor and polycondensed to produce a polycarbonate resin. A plurality of the reactors connected in series, and each pipe between the first reactor of the reactors connected to the plurality of reactors and the step of taking out the polycarbonate resin. temperature following formula defined in T _i in residence time and the pipes of the reaction solution or melt polycarbonate resin in (
This is a method for producing a polycarbonate resin satisfying 1).

T _i : Temperature [K], whichever is higher of the temperature of the reaction liquid or molten carbonate resin at the inlet of the pipe i and the temperature of the reaction liquid or molten polycarbonate resin at the outlet
θ _i : Residence time in pipe i [min]

  In the method of the present invention, the dihydroxy compound containing the dihydroxy compound (A) and the carbonic acid diester are reacted in the presence of a polymerization catalyst (melting) in two or more stages using at least two reactors. (Polycondensation) to produce a polycarbonate resin. Hereinafter, the first reactor is referred to as a first reactor, the second reactor is referred to as a second reactor, the third reactor is referred to as a third reactor, and so on. Further, in this specification, the “reactor” is a device having a heating device for heating to a reaction temperature described later in a step after mixing a dihydroxy compound and a carbonic acid diester, and causing an intentional transesterification reaction. The dissolution tank mainly intended to mix and dissolve the raw materials in advance, and the piping for transferring the raw material mixed solution, even if there is a slight reaction there, Not included in the reactor.

  The reaction system of the production method according to the present invention must be continuous. A molten mixture of raw materials is continuously supplied to the reactor, and a polycondensation reaction is performed to obtain a polycarbonate resin. After the polycondensation process, the process of devolatilizing and removing unreacted raw materials and monohydroxy compounds as reaction by-products in the polycarbonate resin with an extruder equipped with a vacuum vent, heat stabilizer, mold release agent, colorant, etc. A step of removing the foreign matter in the resin with a filter, a step of forming the obtained polycarbonate resin into pellets having a predetermined particle diameter, and the like may be added as appropriate.

The connection between the reactor and the reactor, and the connection between the reactor, the extruder, and the polymer filter may be performed only by direct piping, or may be performed via a preheater or the like as necessary. The pipe is preferably a double pipe type that can transfer the reaction solution or molten polycarbonate resin without cooling and solidifying, has no gas phase on the polymer side, and does not cause dead space.
The pipe whose heat history parameter is defined by the above formula (2) represents a pipe connecting a reactor, an extruder, a filter and the like between the first reactor and the step of taking out the polycarbonate resin. This pipe has only an inlet through which the reaction solution or molten polycarbonate resin flows and an outlet through which it is discharged. A filter for filtering foreign substances in the resin is also regarded as a pipe. The vertical stirring reaction tank, horizontal reactor, and extruder used in the present invention are not regarded as piping because they include a line connected to a vacuum pump.
The temperature of the reaction liquid or molten polycarbonate resin in the pipe used in the above formula (2) is compared with the temperature of the reaction liquid or molten polycarbonate resin at the inlet of the pipe i and the temperature of the reaction liquid or molten polycarbonate resin at the outlet. Te, whichever is higher temperature may be used as the pipe temperature T _i. The residence time is a value [min] obtained by dividing the volume [L] of the pipe by the flow rate [L / hr] per hour of the reaction liquid or molten polycarbonate resin flowing through the pipe.

Ｔ_i：配管ｉの入口における反応液又は溶融ポリカーボネート樹脂の温度と、出口
における反応液又は溶融ポリカーボネート樹脂の温度のいずれか高い方の温度［Ｋ］
θ_i：配管ｉにおける滞留時間［ｍｉｎ］式（３）はポリカーボネート樹脂主鎖の
熱分解反応速度を規定したアレニウスの式より導出された。即ち、式（３）は、一般のアレニウスの式（３'）

Ａ：温度に無関係な因子（頻度因子）
Ｅ：該熱分解反応の生成エネルギー（活性化エネルギー）［ｋＪ／ｍｏｌ］
Ｒ：気体定数［Ｊ／Ｋｍｏｌ］の形をとる。本発明者らは、ポリカーボネート樹脂の色調に対する温度と時間の感度を検証し、着色反応の反応速度パラメータを実験的に取得した。求められた活性化エネルギーからＥ／Ｒを１２０００［Ｋ］とみなし、配管ｉの入口における反応液又は溶融ポリカーボネート樹脂の温度と出口における反応液又は溶融ポリカーボネート樹脂の温度のいずれか高い方の温度［Ｋ］と、配管ｉにおける滞留時間［ｍｉｎ］からχ_iを算出することにより、配管要素ｉにおけるポリカーボネート樹脂の
熱履歴を評価するに至った。 In the above equation (1), the thermal history parameter χ _i in the piping element i is defined as the following equation (3).

T _i : Temperature [K], whichever is the higher of the temperature of the reaction liquid or molten polycarbonate resin at the inlet of the pipe i and the temperature of the reaction liquid or molten polycarbonate resin at the outlet
θ _i : Residence time [min] in pipe i Equation (3) was derived from the Arrhenius equation defining the thermal decomposition reaction rate of the polycarbonate resin main chain. That is, the equation (3) is the general Arrhenius equation (3 ′).

A: Factor unrelated to temperature (frequency factor)
E: Production energy (activation energy) of the thermal decomposition reaction [kJ / mol]
R: takes the form of gas constant [J / Kmol]. The inventors verified the sensitivity of temperature and time to the color tone of the polycarbonate resin, and experimentally obtained the reaction rate parameter of the color reaction. E / R is regarded as 12000 [K] from the determined activation energy, and the temperature of the reaction liquid or molten polycarbonate resin at the inlet of the pipe i and the temperature of the reaction liquid or molten polycarbonate resin at the outlet, whichever is higher [ By calculating χ _i from K] and the residence time [min] in the pipe i, the thermal history of the polycarbonate resin in the pipe element i has been evaluated.

The sum total of the heat history parameters in the piping element i calculated in this way becomes the heat history parameter in the polycondensation step. By setting the thermal history parameter within the range of the above formula (1), the polycarbonate resin satisfying a plurality of quality problems such as improvement of the hue of the obtained polycarbonate resin and reduction of residual low molecular compounds and foreign substances in the polycarbonate resin. Can be obtained.
When the upper limit of the above formula (1) is exceeded, an excessive thermal history is applied to the polycarbonate resin, the hue of the polycarbonate resin is deteriorated, and the residual low molecular components generated by thermal decomposition increase. On the other hand, in order to connect apparatuses, such as a reactor, the piping space more than a certain fixed level is required, so it is difficult to realize a region below the lower limit of the above formula (1).
The upper limit of the formula (1) is 35, but 30 is more preferable. The lower limit of the formula (1) is 4.0, but 6.0 is more preferable.

Further, in the present invention, the molten polycarbonate resin coming out of the final polymerization reactor is in the most viscous state during the production process, and a large pressure loss occurs when it is transported through the piping. Therefore, at least the final polymerization reactor It is preferable to keep the piping at a temperature equal to or higher than the reaction solution temperature. Therefore, the residence time of the pipes after the final polymerization reactor is the largest factor that degrades the quality of the polycarbonate resin.
Therefore, the residence time until the polycarbonate resin is taken out from the final polymerization reactor is preferably within 30 minutes, more preferably within 25 minutes, and particularly preferably within 20 minutes. Even when an extruder or a filter is installed after the final polymerization reactor, it is important to devise the installation of the apparatus so that it can be suppressed to the residence time or less.
Further, in the piping, there is a possibility that decomposed products and colored products generated due to thermal degradation may stay in the reaction solution and the molten polycarbonate resin. In particular, when a large amount of a monohydroxy compound produced from a carbonic acid diester is contained, the reaction solution and the molten polycarbonate resin are likely to be colored due to retention in the piping. On the other hand, if the temperature of the reaction liquid to be transferred is too low, the viscosity becomes high and the transfer becomes difficult. Therefore, it is necessary to set the reaction liquid temperature in the pipe within an appropriate range.
In the present invention, the temperature of the reaction solution in the pipe when transferring a reaction solution containing 6 wt% or more of a monohydroxy compound is 210 ° C. or less, and the reaction solution containing 3 wt% or more and less than 6 wt% is transferred. The reaction liquid temperature in the pipe is preferably 220 ° C. or lower, and the reaction liquid temperature in the pipe in the case of transferring a reaction liquid contained in an amount of 1 wt% or more and less than 3 wt% is preferably 230 ° C. or lower. On the other hand, the reaction liquid temperature in the pipe when transferring the reaction liquid containing 6 wt% or more of the monohydroxy compound is 150 ° C. or higher, and the reaction liquid temperature in the pipe when transferring the reaction liquid containing 3 wt% or more and less than 6 wt% is used. The reaction liquid temperature is preferably 160 ° C. or higher, and the reaction liquid temperature in the pipe in the case of transferring a reaction liquid contained in the range of 1 wt% or more and less than 3 wt% is preferably 170 ° C. or higher.

<Polymerization process>
The polymerization process is divided into two stages, a pre-stage reaction and a post-stage reaction. The pre-reaction is carried out at a temperature of 130 to 230 ° C., preferably 150 to 220 ° C. for 0.1 to 10 hours, preferably 0.5 to 3 hours, to distill off the by-produced monohydroxy compound and generate an oligomer. . In the latter stage reaction, the pressure of the reaction system is gradually lowered from the previous stage reaction, the reaction temperature is gradually raised, and simultaneously the monohydroxy compound generated at the same time is removed from the reaction system. Then, a polycondensation reaction is performed under a temperature range of 200 to 260 ° C., preferably 210 to 250 ° C., to produce a polycarbonate resin. In addition, the pressure in this specification points out what is called an absolute pressure represented on the basis of the vacuum.

As described above, the reactor used in this polymerization step is one in which at least two reactors are connected in series, and the reaction product from the outlet of the first reactor enters the second reactor. The number of reactors to be connected is not particularly limited, but is preferably 2 to 7, more preferably 3 to 5, and still more preferably 3 to 4. The type of the reactor is not particularly limited, but the reactor for the first stage reaction can accommodate one or more vertical stirring reactors, and the reactor for the second stage reaction can accommodate a high-viscosity reaction liquid. One horizontal stirring reactor The above is preferable. In addition, not only the relationship between the former stage and the latter stage, but also between the former stage reactors and between the latter stage reactors, the temperature increased stepwise and the pressure decreased stepwise as the latter reactor was reached. Setting is preferable.
The polycarbonate resin produced in the present invention also increases the viscosity of the reaction solution as the reaction proceeds, as in the case of ordinary polycarbonate resins. Therefore, in each multi-tank reactor, the by-product is produced as the polycondensation reaction proceeds. In order to more effectively remove the monohydroxy compound (which becomes phenol when DPC is used) out of the system and to ensure the fluidity of the reaction solution, the reaction conditions are increased stepwise. It is necessary to set higher temperature and higher vacuum.

  The upper limit temperature of the heating medium for heating each of the reactors is usually 270 ° C., preferably 260 ° C., and particularly preferably 250 ° C. If the temperature of the heating medium is too high, thermal deterioration on the reactor wall surface is promoted, and problems such as an increase in heterogeneous structures, decomposition products, and deterioration in color tone may be caused. In particular, the temperature of the heating medium in the reactor before the final polymerization reactor is preferably less than 250 ° C., since an unreacted dihydroxy compound tends to generate a colored product by thermal decomposition. The lower limit temperature of the heating medium is not particularly limited as long as the reaction temperature can be maintained.

  The reactor used in the present invention may be any known one. For example, a jacket type reactor using hot oil or steam as a heating medium, or a reactor having a coiled heat transfer tube inside may be used.

Next, the method of the present invention will be described more specifically. In the method of the present invention, as a raw material monomer, a dihydroxy compound containing a dihydroxy compound (A) having a fluorene structure and a carbonic acid diester such as diphenyl carbonate (DPC) are respectively melted to prepare a raw material mixed melt (raw material) Preparation step), these compounds are subjected to a polycondensation reaction in multiple stages using a plurality of reactors in a molten state in the presence of a polymerization catalyst (polycondensation step). In this reaction, since a monohydroxy compound is produced as a by-product, the monohydroxy compound is removed from the reaction system to advance the reaction, thereby producing a polycarbonate resin. When DPC is used as the carbonic acid diester, the monohydroxy compound becomes phenol, and the reaction proceeds by removing the phenol under reduced pressure.

  Monohydroxy compounds such as phenol generated in the reactor are collected in a tank, and are collected by purifying as needed from the viewpoint of effective utilization of resources, and then reused as raw materials such as DPC and bisphenol A. It is preferable to do. In the production method of the present invention, the purification method of the by-product monohydroxy compound is not particularly limited, but a distillation method is preferably used.

Next, each process of the manufacturing method will be described.
<Raw material preparation process>
A dihydroxy compound containing a fluorene structure (A) used as a raw material for polycarbonate resin, and a carbonic acid diester are batch, semi-batch or continuous stirring tanks in an inert gas atmosphere such as nitrogen and argon. They are prepared as raw material mixed melts using a mold apparatus, or they are dropped independently into a reaction vessel. The temperature of the melt mixing is, for example, 80.degree. C. or higher when 9,9-bis (4- (2-hydroxyethoxy) phenyl) fluorene (BHEPF) is used as the dihydroxy compound (A) and DPC is used as the carbonic acid diester. 180 degreeC is good, Preferably it selects from the range of 90 to 120 degreeC. Moreover, you may add antioxidant to this raw material mixing melt. Resin obtained by adding commonly known hindered phenolic antioxidants and phosphorus antioxidants to improve the storage stability of raw materials in the raw material preparation process and to suppress coloring during polymerization The hue of can be improved.

The polymerization catalyst to be used is usually prepared as an aqueous solution in advance. The concentration of the catalyst aqueous solution is not particularly limited, and is adjusted to an arbitrary concentration according to the solubility of the catalyst in water. Moreover, it can replace with water and other solvents, such as acetone, alcohol, toluene, and phenol, can also be selected. Specific examples of the polymerization catalyst will be described later. The properties of water used for dissolving the polymerization catalyst are not particularly limited as long as the type and concentration of impurities contained are constant, but usually distilled water, deionized water, and the like are preferably used.
In the method of the present invention, it is also effective to filter the raw material monomer through a filter before polycondensation in order to further reduce foreign matters. Hereinafter, this filter is referred to as a raw material filter.

  In addition, the shape of the material filter at that time may be any type such as basket type, disk type, leaf disk type, tube type, flat cylindrical type, pleated cylindrical type, etc. A pleated type having a large filtration area is preferable. Further, the filter medium constituting the raw material filter may be any of metal wind, laminated metal mesh, metal nonwoven fabric, porous metal plate, etc., but from the viewpoint of filtration accuracy, a laminated metal mesh or metal nonwoven fabric is preferred, among which metal nonwoven fabrics A type in which is fixed by sintering.

  There are no particular restrictions on the material of the material filter, and metal, resin, ceramic, etc. can be used. From the viewpoint of heat resistance and color reduction, a metal filter having an iron content of 80% or less. Of these, stainless steel such as SUS304, SUS316, SUS316L, and SUS310S is preferable.

  When filtering the raw material monomer, it is preferable to use a plurality of filter units in order to extend the life of the raw material filter while ensuring filtration performance. Among them, the opening of the filter in the upstream unit is preferably C [ [mu] m], and when the opening of the filter in the downstream unit is D [[mu] m], in at least one combination, C is preferably larger than D (C> D). When this condition is satisfied, the filter becomes more difficult to block, and the replacement frequency of the raw material filter can be reduced.

The opening of the raw material filter is not particularly limited, but at least one filter preferably has a filtration accuracy of 99% of 10 μm or less, and is preferably on the most upstream side when a plurality of filters are arranged. Is 8 or more, more preferably 10 or more, and preferably 2 or less, more preferably 1 or less on the most downstream side. The opening defined as 99% filtration accuracy refers to the value of χ when the βχ value represented by the following formula (4) determined in accordance with ISO 16889 is 1000.
βχ = (number of particles on the primary side larger than χ μm) / (number of particles on the secondary side larger than χ μm) (4)
(Here, the primary side means before filtration with a filter, and the secondary side means after filtration.)

  In the present invention, the temperature of the raw material fluid when the raw material is passed through the raw material filter is not limited. However, if the raw material is too low, the raw material is solidified. 200 ° C, preferably 100 ° C to 150 ° C.

  Furthermore, in the present invention, any of the raw materials to be used may be filtered, or all of the raw materials may be filtered. The method is not limited, and the dihydroxy compound and the carbonic acid diester are not limited. The raw material mixture may be filtered, or may be mixed after separately filtering. Moreover, in the manufacturing method of this invention, the reaction liquid in the middle of a polycondensation reaction can also be filtered with a filter.

A preferred embodiment of the reaction in the reactor will be described.
<Pre-stage reaction process>
First, the mixture of the dihydroxy compound and the carbonic acid diester is supplied to a vertical stirring reaction tank while being melted, and a polycondensation reaction is performed at a temperature of 130 ° C to 230 ° C.

  This reaction is continuously carried out in a multi-tank system of 1 tank or more, preferably 2-6 tanks, and it is preferable to distill 40% to 95% of the theoretical amount of the monohydroxy compound by-produced. The reaction temperature is preferably 130 ° C to 230 ° C, preferably 150 ° C to 220 ° C, and the pressure is preferably 40 kPa to 1 kPa. In the case of a multi-tank continuous reaction, it is preferable that the temperature of each tank is sequentially increased within the above range, and the pressure of each tank is sequentially decreased within the above range. The average residence time is 0.1 to 10 hours, preferably 0.5 to 5 hours, more preferably 0.5 to 3 hours. If the temperature is too high, thermal decomposition is promoted, the generation of different structures and colored components increases, and the quality of the resin may be deteriorated. On the other hand, if the temperature is too low, the reaction rate is lowered, and thus productivity may be lowered.

  Since the melt polycondensation reaction used in the present invention is an equilibrium reaction, the reaction is promoted by removing the by-product monohydroxy compound out of the reaction system. The pressure is preferably 1 kPa to 40 kPa, more preferably 5 kPa to 30 kPa. If the pressure is too high, the monohydroxy compound will not distill and the reactivity will decrease, and if it is too low, raw materials such as unreacted dihydroxy compound and carbonic acid diester will be distilled, so the molar ratio of the raw materials will shift to the desired molecular weight. It is difficult to control the reaction such as not reaching, and the raw material basic unit may be deteriorated.

<Post reaction process>
Next, the oligomer obtained in the previous polycondensation step is supplied to a horizontal stirring reactor, and a polycondensation reaction is performed at a reaction liquid temperature of 200 ° C. to 260 ° C. in the reactor to obtain a polycarbonate resin. This reaction is continuously carried out in one or more horizontal stirring reactors, preferably 1 to 3 horizontal stirring reactors.

  The reaction temperature is preferably 200 to 260 ° C, more preferably 220 to 250 ° C. The pressure is preferably 13.3 kPa to 10 Pa, and preferably 1 kPa to 10 Pa. Particularly in the final polymerization reactor, the pressure is preferably 1 kPa to 10 Pa, and preferably 0.7 kPa to 10 Pa. The average residence time is 0.1 to 10 hours, preferably 0.5 to 5 hours, more preferably 0.5 to 2 hours.

<Reactor>
In the present invention in which the polycondensation process is performed in a multi-tank system using at least two reactors, a plurality of reactors including a vertical stirring reaction tank are provided to increase the average molecular weight (reduced viscosity) of the polycarbonate resin.

  Here, examples of the reactor include a vertical stirring reactor and a horizontal stirring reactor. Specific examples include a stirring tank reactor, a thin film reactor, a centrifugal thin film evaporation reactor, and a surface renewal type biaxial kneading. Examples thereof include a reactor, a biaxial horizontal stirring reactor, a wet wall reactor, a perforated plate reactor that polymerizes while freely dropping, and a perforated plate reactor with wire that polymerizes while dropping along a wire. As described above, it is preferable to use a vertical stirring reaction tank in the first reaction step, and it is preferable to use a horizontal stirring reactor in the second reaction step.

  In the reactor used in the present invention, from the viewpoint of the color tone of the polycarbonate resin, regardless of whether it is the former stage or the latter stage, from the viewpoint of the color tone of the polycarbonate resin, a part in contact with the raw material monomer or polymerization liquid of the components constituting the reaction apparatus, piping, etc. The surface material of the “wetted part” is a ratio of at least 90% or more of the total surface area of the wetted part, and stainless steel, glass, nickel, tantalum, chromium, Teflon (registered trademark) having a nickel content of 10% by weight or more. ) Is preferably composed of one or more of them. In the present invention, it is only necessary that the surface material of the wetted part is composed of the above-mentioned substance, and a bonding material composed of the above-mentioned substance and another substance or a material obtained by plating the above substance on another substance is used as the surface material. Can be used.

  The vertical stirring reaction tank is a reactor having a vertical rotating shaft and a stirring blade attached to the vertical rotating shaft. Examples of the types of the stirring blades include turbine blades, paddle blades, fiddler blades, anchor blades, full-zone blades (manufactured by Shinko Pantech Co., Ltd.), Sun Meller blades (manufactured by Mitsubishi Heavy Industries, Ltd.), Max Blend blades (Sumitomo Shigeki). Machine Industry Co., Ltd.), helical ribbon blades, twisted lattice blades (manufactured by Hitachi, Ltd.), and the like.

  Further, the horizontal stirring reactor mentioned above has a plurality of stirring blades extending in a substantially vertical direction with respect to the horizontal rotation axis, in which a plurality of stirring blades provided in the inside are horizontal (horizontal). The stirring blades provided on the respective horizontal rotation shafts are arranged so as not to collide with each other by shifting the positions in the horizontal direction. As the type of the stirring blade, for example, a uniaxial stirring blade such as a disk type or a paddle type, HVR, SCR, N-SCR (the above three types are manufactured by Mitsubishi Heavy Industries, Ltd.), Violac (Sumitomo Heavy Industries, Ltd.) In addition to biaxial type stirring blades such as spectacle blades and lattice blades (manufactured by Hitachi, Ltd.), wheel type, saddle type, rod type, window frame type stirring blades, etc. Can be mentioned. At least two stages of such stirring blades are installed per rotation shaft, and the surface of the reaction solution is renewed by scooping up or pushing the reaction solution with the stirring blades. L / D is 1 to 15, preferably 2 to 14, where L is the length of the horizontal rotation axis of the horizontal reactor and D is the rotation diameter of the stirring blade.

  By the way, when a polycarbonate resin is produced by the method of the present invention using a substituted diphenyl carbonate such as diphenyl carbonate or ditolyl carbonate as the carbonic acid diester, phenol or substituted phenol, which is a monohydroxy compound, is produced as a by-product. It is inevitable that it remains inside. However, these monohydroxy compounds such as phenol and substituted phenol may cause odor during molding. The polycarbonate resin obtained by a normal batch reaction, not the continuous type as in the present invention, contains a monohydroxy compound having an aromatic ring such as by-product phenol of 1000 ppm or more. Note that these monohydroxy compounds may have a substituent depending on the raw material used, and may have, for example, an alkyl group having 5 or less carbon atoms.

  In order to reduce the residual low molecular components in the resin, including such a monohydroxy compound, it is effective to reduce the pressure in the final polymerization reactor as much as possible and distill it off. However, a polycarbonate resin using a dihydroxy compound (B) having a structural site of the following formula (12) represented by ISB as a monomer is compared with an aromatic polycarbonate resin using a conventional bisphenol A as a monomer, Since the equilibrium constant of the reaction is large, the molecular weight increase rate in the subsequent reaction is fast. Therefore, if the pressure is lowered, the reaction is promoted too much, so that the control of the reaction becomes difficult. In the method using dihydroxy carbonate (B) having a structural site of the formula (12) described later and diphenyl carbonate as the carbonic acid diester, the amount of the hydroxy terminal and the phenyl carbonate terminal represented by the following structural formula (5) are usually used. The reaction rate is maximized when the amount is equal, but by reducing the amount of hydroxy ends and increasing the amount of phenyl carbonate ends, the viscosity increase rate is moderated and the pressure in the final polymerization reactor is decreased. It becomes possible. Furthermore, the smaller the hydroxy terminal, the more effective the thermal stability of the resulting polycarbonate resin, such as the reduction in coloration when the resin is melted and retained.

  The balance of such end groups can be controlled by the molar ratio of the total dihydroxy compound used in the reaction and the carbonic acid diester when charged to the first reactor. On the other hand, the molar ratio of the carbonic acid diester is preferably 0.990 to 1.030. The molar ratio of the diester carbonate charge to the total dihydroxy compound is more preferably 0.995 to 1.25. If the molar ratio is too large, the hydroxy terminal disappears in the subsequent reaction, and the desired molecular weight cannot be reached. On the other hand, if it is too small, the hydroxy terminal is increased and the thermal stability of the resulting resin is deteriorated. By controlling the terminal balance in this way, it is possible to control the rate of viscosity increase in the final polymerization reactor, and the pressure in the final polymerization reactor can be reduced. The pressure in the final polymerization reactor is preferably 1 kPa or less, more preferably 0.7 kPa or less, and particularly preferably 0.5 kPa or less. In addition, although a pressure is so preferable that it is low, it becomes a limit of pressure reduction in 10 Pa in many cases.

Thus, the amount of hydroxy end groups in the polycarbonate resin obtained by polycondensation in this invention is preferably 60 mol / ton or less at the outlet of the final polymerization reactor. More preferably, it is 50 mol / ton or less, Most preferably, it is 40 mol / ton or less. The smaller the amount of hydroxy end groups of the resulting polycarbonate resin, the better from the viewpoint of thermal stability. However, when the hydroxy ends are completely disappeared, the reaction may end and the desired molecular weight may not be reached. End is 5 mol / to
It is preferable to contain n or more, and more preferably 10 mol / ton or more. Hydroxy end groups can be controlled by the molar ratio of the diester carbonate charge to the total dihydroxy compound described above. By increasing the amount of carbonic acid diester charged, the amount of hydroxy end groups decreases.

  Further, the amount of the monohydroxy compound contained in the polycarbonate resin obtained by polycondensation in the present invention is preferably 1200 ppm or less, more preferably 1000 ppm or less, particularly preferably 800 ppm or less at the outlet of the final polymerization reactor. is there. However, it is difficult to remove completely industrially, and the lower limit of the content of the monohydroxy compound is usually 1 ppm.

<Steps after polycondensation reaction>
The polycarbonate resin obtained by polycondensation according to the present invention may be filtered through a filter in the molten state without solidifying after the polycondensation reaction described above. In particular, in order to remove low molecular weight components contained in the resin and to add and knead a heat stabilizer and the like, the resin obtained by polycondensation is introduced into an extruder, and then the resin discharged from the extruder is It is preferable to filter using a filter.
In the method of the present invention, examples of the method for filtering the polycarbonate resin obtained by polycondensation using a filter include the following methods. In order to generate the pressure necessary for filtration, the final polymerization reactor is extracted in a molten state using a gear pump, a screw, etc., and filtered through a filter, and the final polymerization reactor is melted and uniaxially or biaxially extruded. The resin is supplied to the machine, melt-extruded, filtered through a filter, cooled and solidified in the form of a strand, and pelletized with a rotary cutter or the like, or from the final polymerization reactor in a molten state, uniaxially or biaxially. After supplying the resin to the extruder of the shaft and melt-extruding it, it is once cooled and solidified in the form of a strand, pelletized, the pellet is again introduced into the extruder, filtered through a filter, and cooled and solidified in the form of a strand. , Pelletizing method, extracted from the final polymerization reactor in a molten state, cooled and solidified in the form of a strand without passing through an extruder, and once pelletized After the supplies pellets to an extruder uniaxial or biaxial, after melt extrusion, and filtered through a filter, which is solidified by cooling in the form of a strand method or the like for pelletizing. In particular, in order to minimize thermal history and suppress thermal deterioration such as deterioration of hue and molecular weight, resin is supplied from the final polymerization reactor to a uniaxial or biaxial extruder in a molten state and melted. After extrusion, a method of directly filtering with a filter, cooling and solidifying in the form of a strand from a die head, and pelletizing with a rotary cutter or the like is preferable. This will be specifically described below.

  The form of the extruder used in the method of the present invention is not limited, but usually a single or twin screw extruder is used. Among these, a twin screw extruder is preferable for improving the devolatilization performance described later and for uniform kneading of the additive. In this case, the rotation direction of the shaft may be different or the same. From the viewpoint of kneading performance, a different direction is preferable, but the same direction is preferable from the viewpoint of suppressing the temperature of the resin from increasing due to shear heat generation and deteriorating the hue. The use of an extruder can stabilize the supply of polycarbonate resin to the filter.

In addition, in the polycarbonate resin obtained by polycondensation as described above, usually the hue, heat stability, raw material monomers that may adversely affect the product due to bleed-out, etc. Low molecular weight compounds such as monohydroxy compounds and polycarbonate oligomers remain, but these are devolatilized and removed by using an extruder having a vent port, preferably by reducing the pressure from the vent port using a vacuum pump or the like. It is also possible to do. Moreover, volatile liquids, such as water, can be introduce | transduced in an extruder, and devolatilization can also be accelerated | stimulated. The number of vent ports may be one or plural, but preferably two or more.
Usually, in an extruder, the temperature of the resin rises due to shearing heat generation. In order to improve the hue, it is important to suppress the temperature rise in the extruder as much as possible. Since shear heat generation is particularly affected by the rotational speed of the screw, the effect of adjusting the rotational speed to a low value is high. However, if the rotational speed is too low, there is a limit because there is a concern that the load on the motor will increase or the resin will wind up around the vent port and block the vent line. The cylinder temperature of the extruder is also preferably as low as the motor load permits.

  Furthermore, in the above-mentioned extruder, a heat stabilizer, a neutralizing agent, an ultraviolet absorber, a release agent, an antistatic agent, a lubricant, a lubricant, a plasticizer, a compatibilizing agent and the like that are generally known are added. It can also be kneaded.

  In the present invention, in order to remove foreign matters such as burns and gels in the polycarbonate resin obtained by polycondensation, it may be filtered through a filter. Above all, in order to remove residual monomers, by-product phenol, etc. by vacuum devolatilization and to mix additives such as heat stabilizers and mold release agents, the polycarbonate resin is extruded with the above extruder and then filtered with a filter. It is preferable.

  As the form of the filter, known ones such as a candle type, a pleat type, and a leaf disk type can be used. Among them, a leaf disk type that can take a large filtration area with respect to the storage container of the filter is preferable, and a large filtration area can be obtained. It is preferable to use a combination of two or more.

  The filter used in the present invention is configured by combining a holding member (also referred to as a retainer) with a filtering member (hereinafter sometimes referred to as a medium), and these filters are stored (in some cases, a plurality or plural). It is used in the form of a unit (sometimes called a filter unit) stored in a container.

  In the present invention, a type in which a plurality of aperture media are overlapped so that the differential pressure (pressure loss) of the filter is small and the apertures become finer in order from the resin intrusion direction is preferable. For the purpose of crushing the gel, it is also possible to use a type obtained by sintering metal powder.

  The material of the filter media is not limited as long as it has the strength and heat resistance necessary for filtration of the obtained polycarbonate resin, but stainless steel such as SUS316 and SUS316L with a low iron content is particularly preferable. As the kind of weaving, a nonwoven fabric type can be used in addition to a regular weaving part of the foreign matter, such as a plain weave, a twill weave, a plain tatami mat, a twill mat weave, and the like. In the present invention, a non-woven fabric type having a high gel-capturing ability, particularly a type in which steel wires constituting the non-woven fabric are sintered and fixed is preferable.

In the present invention, the aperture of the filter is preferably 50 μm or less, more preferably 40 μm or less, still more preferably 20 μm or less, and preferably 10 μm or less in order to reduce foreign matter, as 99% filtration accuracy. If the aperture is small, the pressure loss at the filter increases, which may cause the filter to be damaged or the polycarbonate resin to deteriorate due to shear heat generation. Therefore, the filtration accuracy of 99% should be 1 μm or more. Is preferred.
Note that the aperture of the filter referred to here is also determined in accordance with the above-mentioned ISO16889.

  Of the above-mentioned filters, filters containing iron, such as stainless steel, tend to deteriorate the resin during filtration at a high temperature exceeding 200 ° C., and therefore may be passivated before use. preferable. Passivation treatment is a method in which the filter is immersed in an acid such as nitric acid or an acid is passed through the filter to form a passivation on the surface, a method of baking (heating) treatment in the presence of water vapor or oxygen, Although the method etc. which use these together are mentioned, it is preferable to implement both nitric acid treatment and baking.

  The roasting temperature is preferably 350 ° C. to 500 ° C., preferably 350 ° C. to 450 ° C., and the roasting time is 3 hours to 200 hours, preferably 5 hours to 100 hours. If the roasting temperature is too low or the time is too short, the formation of the passive state becomes insufficient, and the polycarbonate resin tends to deteriorate during filtration. On the other hand, if the temperature of roasting is too high or the time is too long, the filter media may be severely damaged and the required filtration accuracy may not be achieved.

  Further, the concentration of nitric acid in the treatment with nitric acid is preferably 5 to 50% by weight, preferably 10 to 30% by weight, and the treatment temperature is preferably 5 to 100 ° C, preferably Is 50 ° C. to 90 ° C., and the treatment time is 5 minutes to 120 minutes, preferably 10 minutes to 60 minutes. If the concentration of nitric acid is too low, the processing temperature is too low, or the processing time is too short, the formation of passives will be insufficient, the concentration of nitric acid will be too high, the processing temperature will be too high, or the processing time will be If it is too long, the filter media will be severely damaged and the required filtration accuracy may not be achieved.

  The material of the containment vessel of the filter used in the method of the present invention is not limited as long as it has strength and heat resistance that can withstand resin filtration, but preferably SUS316 with a low iron content, Stainless steel such as SUS316L.

  Further, the storage container of the filter may be arranged such that the supply port and the discharge port of the polycarbonate resin are arranged substantially horizontally, arranged substantially vertically, or arranged obliquely. In order to prevent gas and polycarbonate resin from staying in the filter storage container and prevent deterioration of the polycarbonate resin, it is preferable that the polycarbonate resin supply port is disposed at the bottom of the filter storage container and the discharge port is disposed at the top. .

  Furthermore, in the method of the present invention, it is preferable to arrange a gear pump between the extruder and the filter in order to stabilize the supply amount of the polycarbonate resin to the filter. Although there is no restriction | limiting about the kind of gear pump, Especially the self-circulation type which does not use a gland packing for a seal | sticker part is preferable from a viewpoint of foreign material reduction.

  In the present invention, in the case of stranding or pelletization in which the polycarbonate resin is in direct contact with the outside air, it is preferably class 7 as defined in JIS B 9920 (2002), more preferably, in order to prevent contamination by foreign matter from the outside air. It is desirable to carry out in a clean room with higher cleanliness than class 6.

  The polycarbonate resin filtered by the filter is discharged from the die head in the form of a strand, cooled and solidified, and pelletized by a rotary cutter or the like, but when the pelletized, a cooling method such as air cooling or water cooling is used. It is preferable to do this. 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 using water cooling, it is desirable to use water from which metal in water has been removed with an ion exchange resin or the like, and further, foreign matter in water has been removed with a water filter. The aperture of the water filter to be used is preferably 10 to 0.45 μm as the filtration accuracy for 99% removal.

By the method of the present invention, a resin with less coloring and less foreign matters can be obtained. Specifically, when the polycarbonate resin produced by the method of the present invention is formed into a film having a thickness of 35 μm ± 5 μm, foreign substances having a maximum length of 25 μm or more contained in the film are preferably 1000 / m ² or less. More preferably, it can be 500 pieces / m ² or less, and most preferably 200 pieces / m ² or less.
In the present invention, by suppressing the thermal decomposition of the molten resin after the final polymerization reactor as described above, the amount of the monohydroxy compound in the molten polycarbonate resin at the outlet of the final polymerization reactor is A [ppm], and finally When the content of the monohydroxy compound in the obtained polycarbonate resin is B [ppm], it is preferable to satisfy the following formula (6).
A-B ≧ 100 (6)

<Example of manufacturing equipment>
Next, an example of the method of the present invention to which the present embodiment is applied will be specifically described with reference to FIG. The production apparatus, raw material, and catalyst described below are examples of embodiments of the present invention, and the present invention is not limited to the examples described below.

FIG. 1 is a diagram showing an example of a manufacturing apparatus used in the method of the present invention. In the production apparatus shown in FIG. 1, the polycarbonate resin includes a raw material preparation step for preparing the raw material dihydroxy compound and carbonic acid diester, and a polycondensation step in which these raw materials are polycondensed using a plurality of reactors in a molten state. It is manufactured after. The distillate produced in the polycondensation step is liquefied by the condensers 12a, 12b, 12c and 12d and collected in the distillate collection tank 14a.
After the polycondensation step, the step of devolatilizing and removing unreacted raw materials and reaction byproducts in the molten polycarbonate resin, the step of adding a heat stabilizer, a release agent, etc., and forming the polycarbonate resin into pellets of a predetermined particle size Through the process, polycarbonate pellets are formed.

  The following are 9,9-bis (4- (2-hydroxyethoxy) phenyl) fluorene (BHEPF) as the raw dihydroxy compound (A), isosorbide (ISB) as the dihydroxy compound (B), and other dihydroxy compounds. A case where diethylene glycol (DEG) is used, diphenyl carbonate (DPC) is used as a carbonic acid diester as a raw material, and magnesium acetate is used as a catalyst will be described as an example.

  First, in the raw material preparation step, a DPC melt prepared at a predetermined temperature in a nitrogen gas atmosphere is supplied from the raw material supply port 1a to the raw material mixing tank 2a. Subsequently, the BHEPF powder, ISB melt, and DEG melt measured in a nitrogen gas atmosphere are supplied to the raw material mixing tank 2a from the raw material supply ports 1b, 1c, and 1d, respectively. And these are mixed within the raw material mixing tank 2a, and a raw material mixing melt is obtained.

  Next, the obtained raw material mixed melt is continuously supplied to the first vertical stirring reaction tank 6a via the raw material supply pump 4a and the raw material filter 5a. Moreover, calcium acetate aqueous solution is continuously supplied as a raw material catalyst from the catalyst supply port 1e in the middle of the transfer piping of the raw material mixed melt.

  In the polycondensation step of the production apparatus of FIG. 1, a first vertical stirring reaction tank 6a, a second vertical stirring reaction tank 6b, a third vertical stirring reaction tank 6c, and a fourth horizontal stirring reactor 6d are provided in series. It is done. In each reactor, the liquid level is kept constant, polycondensation reaction is performed, and the polymerization reaction liquid discharged from the bottom of the first vertical stirring reaction tank 6a is continuously supplied to the second vertical stirring reaction tank 6b. The third vertical stirring reaction tank 6c is successively and continuously supplied to the fourth horizontal stirring reactor 6d, and the polycondensation reaction proceeds. The reaction conditions in each reactor are preferably set so as to become high temperature, high vacuum, and low stirring speed as the polycondensation reaction proceeds. When the apparatus of FIG. 1 is used, the fourth horizontal stirring reactor 6d corresponds to the final polymerization reactor in the present invention, and the third vertical stirring reactor 6c corresponds to the reactor immediately before the final polymerization reactor. To do.

  The first vertical stirring reaction tank 6a, the second vertical stirring reaction tank 6b, and the third vertical stirring reaction tank 6c are provided with Max Blend blades 7a, 7b, 7c, respectively. The fourth horizontal stirring reactor 6d is provided with a biaxial glasses-type stirring blade 7d. Since the reaction liquid to be transferred becomes highly viscous after the third vertical stirring reaction tank 6c, a gear pump 4b is provided.

  In the first vertical stirring reaction tank 6a and the second vertical stirring reaction tank 6b, the amount of heat supplied may be particularly large, so that the internal heat exchangers 8a and 8b are respectively provided so that the heat medium temperature does not become excessively high. Is provided.

  These four reactors are respectively equipped with distillation tubes 11a, 11b, 11c, and 11d for discharging by-products generated by the polycondensation reaction. For the first vertical stirring reaction tank 6a and the second vertical stirring reaction tank 6b, reflux condensers 9a and 9b and reflux pipes 10a and 10b are provided in order to return a part of the distillate to the reaction system. The reflux ratio can be controlled by appropriately adjusting the pressure of the reactor and the heat medium temperature of the reflux condenser.

  The distillation pipes 11a, 11b, 11c, and 11d are connected to condensers 12a, 12b, 12c, and 12d, respectively, and each reactor is in a predetermined depressurized state by a decompression device 13a, 13b, 13c, and 13d. To be kept.

  In the present embodiment, by-products such as phenol (monohydroxy compound) are continuously liquefied and recovered from the condensers 12a, 12b, 12c, and 12d attached to each reactor. In addition, a cold trap (not shown) is provided downstream of the condensers 12c and 12d attached to the third vertical stirring reactor 6c and the fourth horizontal stirring reactor 6d, respectively, so that by-products are continuously present. Solidified and recovered.

  The reaction liquid raised to a predetermined molecular weight is withdrawn as molten polycarbonate resin from the fourth horizontal stirring reactor 6d, and transferred to the twin screw extruder 15a by the gear pump 4c. The twin screw extruder is equipped with a vacuum vent to remove residual low molecular components in the polycarbonate resin. Further, an antioxidant, a light stabilizer, a colorant, a release agent, and the like are added as necessary.

  Resin is supplied from the twin-screw extruder 15a to the polymer filter 15b by the gear pump 4d, and foreign matter is filtered. The resin that has passed through the filter is extracted in the form of a strand from the die head, cooled with water in the strand cooling tank 16a, and then pelletized by the strand cutter 16b. The pellets are pneumatically transported by an air blower 16c and sent to a product hopper 16d. A predetermined amount of product is packed in the product bag 16f by the measuring instrument 16e.

<Start of melt polycondensation in continuous production equipment>
In the present embodiment, polycondensation based on a transesterification reaction between a dihydroxy compound and a carbonic acid diester is started according to the following procedure.

First, in the continuous production apparatus shown in FIG. 1, four reactors connected in series (first vertical stirring reaction tank 6a, second vertical stirring reaction tank 6b, third vertical stirring reaction tank 6c, The four horizontal stirring reactor 6d) is set in advance to a predetermined reaction liquid temperature and pressure, respectively. Here, the reaction liquid temperature in each reactor, the heat medium temperature and pressure in each reactor are not particularly limited, but are preferably set as follows.
(First vertical stirring reaction tank 6a)
Reaction solution temperature in reactor: 130 ° C. to 230 ° C., pressure: 40 kPa to 10 kPa, heating medium temperature 140 ° C. to 240 ° C., reflux ratio 0.01 to 10
(Second vertical stirring reaction tank 6b)
Reaction solution temperature in reactor: 150 ° C. to 230 ° C., pressure: 40 kPa to 8 kPa, heating medium temperature 160 ° C. to 240 ° C., reflux ratio 0.01 to 5
(Third vertical stirring reaction tank 6c)
Reaction solution temperature in reactor: 170 ° C. to 230 ° C., pressure: 20 kPa to 1 kPa, heating medium temperature 180 ° C. to 240 ° C.
(Fourth horizontal stirring reactor 6d)
Reaction liquid temperature in reactor: 200 ° C. to 260 ° C., pressure: 5 kPa to 10 Pa, temperature of heating medium 210 to 270 ° C.

  Next, separately, the dihydroxy compound and the carbonic acid diester are mixed at a predetermined molar ratio in a raw material mixing tank 2a in a nitrogen gas atmosphere to obtain a raw material mixed melt.

  Subsequently, after the reaction liquid temperature and pressure in the four reactors described above reach the range of ± 5% of the respective set values, the raw material mixed melt prepared in the raw material mixing tank 2a is separately prepared. , Continuously fed into the first vertical stirring reaction tank 6a. Simultaneously with the start of the supply of the raw material mixed melt, the catalyst is continuously supplied from the catalyst supply port 1e into the first vertical stirring reaction tank 6a to start the transesterification reaction.

  In the first vertical stirring reaction tank 6a in which the transesterification reaction is performed, the liquid level of the polymerization reaction solution is kept constant so as to have a predetermined average residence time. As a method of keeping the liquid level in the first vertical stirring reaction tank 6a constant, usually, a valve (not shown) provided in a polymer discharge line at the bottom of the tank while detecting the liquid level with a liquid level gauge or the like. A method for controlling the opening degree may be mentioned.

  Subsequently, the polymerization reaction liquid is discharged from the bottom of the first vertical stirring reaction tank 6a, discharged to the second vertical stirring reaction tank 6b, and subsequently discharged from the bottom of the second vertical stirring reaction tank 6b. Sequentially and continuously supplied to the third vertical stirring reaction tank 6c. In this pre-stage reaction step, 50% to 95% of the theoretical amount of phenol produced as a by-product is distilled off to produce oligomers.

  Next, the oligomer obtained in the preceding reaction step is transferred by the gear pump 4b, supplied to the horizontal stirring reactor 6d, and a by-product under temperature and pressure conditions suitable for performing the latter reaction as described later. Phenol and partially unreacted monomer are removed from the system through the distillation pipe 11d to produce a polycarbonate resin.

  This horizontal stirring reactor 6d has one or two or more horizontal rotation shafts, and includes a disk shape, a wheel shape, a saddle shape, a rod shape, a window frame shape and the like extending in the vertical direction from the horizontal rotation shaft. Two or more stirrer blades are installed in the horizontal direction at least in a horizontal direction by combining one or more kinds of stirring blades. When there are two or more horizontal rotation shafts, the stirring blades provided on the respective horizontal rotation shafts are arranged with their horizontal positions shifted so as not to collide with each other. The surface of the reaction solution is renewed by scooping up or spreading the reaction solution with such a stirring blade. The shape is such that L / D is 1 to 15 where L is the length of the horizontal rotation shaft and D is the rotation diameter of the stirring blade. In the present specification, the term “reaction liquid surface renewal” means that the reaction liquid on the liquid surface is replaced with the reaction liquid below the liquid surface.

  The reaction temperature in the latter reaction step is usually 200 to 260 ° C., preferably 220 to 250 ° C., and the reaction pressure is usually 5 kPa to 10 Pa, preferably 1 kPa to 10 Pa.

  In the method of the present invention, by using a horizontal stirring reactor 6d having a larger hold-up than the twin-screw vent type extruder in terms of the device structure, the residence time of the reaction solution can be set appropriately and shearing can be performed. By suppressing the heat generation, the temperature can be lowered, and it becomes possible to obtain a polycarbonate resin with improved color tone and excellent mechanical properties. The horizontal stirring reactor is an apparatus having a horizontal axis and mutually discontinuous stirring blades mounted substantially at right angles to the horizontal axis, and does not have a screw portion unlike an extruder. In the method of the present invention, it is preferable to use at least one such horizontal stirring reactor.

In the present embodiment, in the continuous production apparatus shown in FIG. 1, after the reaction liquid temperature and pressure in the four reactors reach predetermined values, the raw material mixed melt and the catalyst are continuously supplied via the preheater. The melt polycondensation based on the transesterification reaction is started. As a result, the average residence time of the polymerization reaction liquid in each reactor becomes equal to that during steady operation immediately after the start of melt polycondensation. As a result, the polymerization reaction liquid does not receive an excessive heat history, and foreign matters such as gel or burns generated in the obtained polycarbonate resin are reduced. Also, the color tone is good.

<Raw materials and catalysts>
Hereinafter, raw materials and catalysts that can be used in the method for producing a polycarbonate resin of the present invention will be described.
(Dihydroxy compound)
The dihydroxy compound used for the production of the polycarbonate resin of the present invention contains at least a dihydroxy compound having a fluorene structure (fluorene-based dihydroxy compound) (referred to as dihydroxy compound (A) in the present invention). From the viewpoint of heat resistance, mechanical strength, optical properties and polymerization reactivity of the obtained polycarbonate resin, the dihydroxy compound (A) is preferably represented by the following formula (11) having a 9,9-diphenylfluorene structure. Used for.

（上記一般式（１１）中、Ｒ¹〜Ｒ⁴はそれぞれ独立に、水素原子、置換若しくは無置換の炭素数１〜炭素数２０のアルキル基、置換若しくは無置換の炭素数６〜炭素数２０のシクロアルキル基、または、置換若しくは無置換の炭素数６〜炭素数２０のアリール基を表し、Ｘは置換若しくは無置換の炭素数２〜炭素数１０のアルキレン基、置換若しくは無置換の炭素数６〜炭素数２０のシクロアルキレン基、または、置換若しくは無置換の炭素数６〜炭素数２０のアリーレン基を表す。ｍ及びｎはそれぞれ独立に０〜５の整数である。）

(In the general formula (11), R ^{1 to} R ⁴ are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted carbon number 6 to 20 carbon atoms. Or a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, X is a substituted or unsubstituted alkylene group having 2 to 10 carbon atoms, substituted or unsubstituted carbon number A cycloalkylene group having 6 to 20 carbon atoms or a substituted or unsubstituted arylene group having 6 to 20 carbon atoms, m and n are each independently an integer of 0 to 5).

R ^{1 to} R ⁴ are preferably each independently a hydrogen atom or unsubstituted or an ester group, an ether group, a carboxylic acid, an amide group, or a halogen-substituted alkyl group having 1 to 6 carbon atoms, More preferably, it is a 1-6 alkyl group. X is unsubstituted or substituted by an ester group, an ether group, a carboxylic acid, an amide group, or a halogen-substituted alkylene group having 2 to 10 carbon atoms, unsubstituted or an ester group, an ether group, a carboxylic acid, an amide group, or a halogen. Preferred are cycloalkylene groups having 6 to 20 carbon atoms, or unsubstituted or ester groups, ether groups, carboxylic acids, amide groups, and halogen-substituted arylene groups having 6 to 20 carbon atoms. More preferred is an alkylene group of ˜6. M and n are each independently preferably an integer of 0 to 2, with 0 or 1 being preferred.

Specifically, as the dihydroxy compound (A), 9,9-bis (4- (2-hydroxyethoxy) phenyl) fluorene, 9,9-bis (4-hydroxyphenyl) fluorene, 9,9-bis (4 -Hydroxy-2-methylphenyl) fluorene, 9,9-bis (4- (2-hydroxypropoxy) phenyl) fluorene, 9,9-bis (4- (2-hydroxyethoxy) -3-methylphenyl) fluorene, 9,9-bis (4- (2-hydroxypropoxy) -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-t rt-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, and the like. 9,9-bis (4- (2-hydroxyethoxy) phenyl) fluorene and 9,9-bis (4-hydroxy-2) from the viewpoint of optical properties, heat resistance, mechanical properties, or availability and production -Methylphenyl) fluorene is preferred. 9,9-bis (4- (2-hydroxyethoxy) phenyl) fluorene is particularly preferable.

（但し、上記式（１２）で表される部位が−ＣＨ₂−ＯＨの一部を構成する部位である場
合、およびジヒドロキシ化合物（Ｂ）が前記フルオレン構造を有するジヒドロキシ化合物である場合を除く。）
すなわち、ジヒドロキシ化合物（Ｂ）には、−ＣＨ₂−ＯＨ以外に式（１２）で表され
る部位を有さない化合物は含まれないが、−ＣＨ₂−ＯＨ以外に−ＣＨ₂−Ｏ−ＣＨ₂−等
の式（１２）で表される部位を有する化合物は含まれる。 The polycarbonate resin produced by the method of the present invention may contain a structural unit derived from a dihydroxy compound other than the above-mentioned fluorene-based dihydroxy compound in order to adjust it to desired optical properties, and has an appropriate birefringence or low From the viewpoint of optical properties such as photoelastic coefficient, heat resistance, mechanical strength, etc., one or more dihydroxy compounds (B) having a site represented by the formula (12) in a part of the structure are preferably used. . Specific examples include oxyalkylene glycols, dihydroxy compounds having an ether group bonded to an aromatic group in the main chain, and dihydroxy compounds having a cyclic ether structure.

(However, moiety represented by the above formula (12) except when the case is a portion constituting a part of -CH ₂ -OH, and dihydroxy compound (B) is a dihydroxy compound having a fluorene structure. )
That is, the dihydroxy compound (B), but does not include the compound having no moiety represented by the formula (12) in addition to -CH ₂ -OH, -CH ₂ -O- besides -CH ₂ -OH Compounds having a site represented by the formula (12) such as CH ₂ — are included.

  Examples of the oxyalkylene glycols include diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, and polypropylene glycol.

Examples of the dihydroxy compound having an ether group bonded to an aromatic group in the main chain include 2,2-bis (4- (2-hydroxyethoxy) phenyl) propane and 2,2-bis (4- (2-hydroxy Propoxy) phenyl) propane, 1,3-bis (2-hydroxyethoxy) benzene, 4,4′-bis (2-hydroxyethoxy) biphenyl, bis (4- (
2-hydroxyethoxy) phenyl) sulfone and the like.

  Examples of the dihydroxy compound having a cyclic ether structure include a dihydroxy compound represented by the following formula (13), a spiro glycol represented by the following formula (14) and the following formula (15), and the like. The “cyclic ether structure” of the above “dihydroxy compound having a cyclic ether structure” means a structure having an ether group in the cyclic structure and a structure in which the carbon constituting the cyclic chain is an aliphatic carbon. To do. Among these, those having a plurality of ether groups are preferred, those having a plurality of cyclic ether structures are more preferred, and those having two cyclic ether structures are particularly preferred.

  However, examples of the dihydroxy compound represented by the formula (13) include isosorbide (ISB), isomannide, and isoidet which are in a stereoisomeric relationship, and these may be used alone or in combination of two kinds. A combination of the above may also be used.

  Among these dihydroxy compounds (B), it is preferable to use a dihydroxy compound having no aromatic ring structure from the viewpoint of the optical properties of the polycarbonate resin. Ease of availability, handling, reactivity during polymerization, and polycarbonate resin to be obtained From the viewpoint of the hue, a dihydroxy compound having a cyclic ether structure, represented by a hydroxy compound represented by formulas (13), (14), and (15), is more preferred, and a dihydroxy compound represented by the above formula (13) A dihydroxy compound having two cyclic ether structures such as anhydrosugar alcohol, which is a dihydroxy compound having two sugar-derived cyclic ether structures such as a compound, and spiroglycol represented by the following formula (14) is more preferred. 13) Sugar-derived cyclic ether structures such as dihydroxy compounds represented by 13) Anhydrosugar alcohol a dihydroxy compound having two, obtain and ease of manufacture, light resistance, optical properties, moldability, heat resistance, and most preferred from the standpoint of carbon neutral.

  These dihydroxy compounds (B) may be used alone or in combination of two or more depending on the required performance of the polycarbonate resin to be obtained. In order to obtain desired optical characteristics and further balance physical properties such as heat resistance and mechanical strength, the molar ratio of (A) / (B) is preferably 10/90 to 70/30, more preferably 20/80. It is preferably ~ 60/40.

The polycarbonate resin produced by the method of the present invention is the dihydroxy compound (A) described above.
And a structural unit derived from a dihydroxy compound other than the dihydroxy compound (B) (hereinafter sometimes referred to as “dihydroxy compound (C)”). The dihydroxy compound (C) may be a linear fatty acid. A dihydroxy compound of an aromatic hydrocarbon, a dihydroxy compound of an alkyl branched aliphatic hydrocarbon, a dihydroxy compound of an alicyclic hydrocarbon, an aromatic bisphenol, and the like.

  Examples of the straight-chain aliphatic hydrocarbon dihydroxy compound include ethylene glycol, 1,3-propanediol, 1,2-propanediol, 1,4-butanediol, 1,3-butanediol, and 1,2-butane. Examples include diol, 1,5-heptanediol, 1,6-hexanediol, 1,10-decanediol, 1,12-dodecanediol, and the like.

  Examples of the dihydroxy compound of the alkyl branched aliphatic hydrocarbon include neopentyl glycol and hexylene glycol.

  Examples of the alicyclic hydrocarbon dihydroxy compound include 1,2-cyclohexanediol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, tricyclodecane dimethanol, Pentacyclopentadecane dimethanol, 2,6-decalin dimethanol, 1,5-decalin dimethanol, 2,3-decalin dimethanol, 2,3-norbornane dimethanol, 2,5-norbornane dimethanol, 1,3- And dihydroxy compounds derived from terpene compounds such as adamantanedimethanol and limonene.

Examples of the aromatic bisphenols include 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis (3-methyl-4-hydroxyphenyl) propane, and 2,2-bis (4-hydroxy-3). , 5-dimethylphenyl) propane, 2,2-bis (4-hydroxy-3,5-diethylphenyl) propane, 2,2-bis (4-hydroxy- (3-phenyl) phenyl) propane, 2,2- Bis (4-hydroxy- (3,5-diphenyl) phenyl) propane, 2,2-bis (4-hydroxy-3,5-dibromophenyl) propane, bis (4-hydroxyphenyl) methane, 1,1-bis (4-hydroxyphenyl) ethane, 2,2-bis (4-hydroxyphenyl) butane, 2,2-bis (4-hydroxyphenyl) pentane, 1,1 Bis (4-hydroxyphenyl) -1-phenylethane, bis (4-hydroxyphenyl) diphenylmethane, 2,4′-dihydroxy-diphenylmethane, bis (4-hydroxy-3-nitrophenyl) methane, 3,3-bis ( 4-hydroxyphenyl) pentane, 1,3-bis (2- (4-hydroxyphenyl) -2-propyl) benzene, 1,4-bis (2- (4-hydroxyphenyl) -2-propyl) benzene, 2 , 2-bis (4-hydroxyphenyl) hexafluoropropane, 1,1-bis (4-hydroxyphenyl) cyclohexane, bis (4-hydroxyphenyl) sulfone, 2,4′-dihydroxydiphenylsulfone, bis (4-hydroxy Phenyl) sulfide, bis (4-hydroxy-3-methylphenyl) sulfur And bis (4-hydroxyphenyl) disulfide, 4,4′-dihydroxydiphenyl ether, 4,4′-dihydroxy-3,3′-dichlorodiphenyl ether, and the like.

  These dihydroxy compounds (C) may also be used in combination with the dihydroxy compound (A) alone or in combination of two or more depending on the required performance of the polycarbonate resin to be obtained. ) And the dihydroxy compound (B). Among these, from the viewpoint of the optical properties of the polycarbonate resin, a dihydroxy compound having no aromatic ring structure in the molecular structure, that is, an aliphatic hydrocarbon dihydroxy compound or an alicyclic hydrocarbon dihydroxy compound is preferable. May be.

Among the above, as aliphatic hydrocarbon dihydroxy compounds suitable for the polycarbonate resin produced by the method of the present invention, 1,3-propanediol, 1,4-butanediol, 1,5-heptanediol, 1 From the viewpoint of mechanical properties, a straight-chain aliphatic hydrocarbon dihydroxy compound having 3 to 6 carbon atoms and having hydroxy groups at both ends, such as 1,6-hexanediol, is preferable. 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, tricyclodecane dimethanol are preferred, and 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol are more preferred. Cyclohexa such as methanol and 1,4-cyclohexanedimethanol Dihydroxy compound having a structure is preferred.

  By using the dihydroxy compound (C) in combination with the dihydroxy compound (A) or the dihydroxy compound (A) and the dihydroxy compound (B), the flexibility of the polycarbonate resin is improved, the heat resistance is improved, and the molding is performed. It is also possible to obtain effects such as improvement of sex. However, when the content ratio of the structural unit derived from the dihydroxy compound (C) is too large, the heat resistance may be lowered. Therefore, the dihydroxy compound relative to the number of moles of the structural unit derived from all the dihydroxy compounds ( The proportion of structural units derived from C) is preferably 40 mol% or less, more preferably 30 mol% or less, particularly preferably 25 mol% or less. On the other hand, it is preferably at least 1 mol%, more preferably at least 3 mol%, particularly preferably at least 5 mol%.

  All dihydroxy compounds used in the method of the present invention may contain stabilizers such as reducing agents, antioxidants, oxygen scavengers, light stabilizers, antacids, pH stabilizers, heat stabilizers and the like. . Among these, since the dihydroxy compound (B) is susceptible to thermal alteration in the presence of oxygen, the reducing agent, antioxidant, oxygen scavenger, light stabilizer, antacid, pH stabilizer, heat stabilizer, etc. It is preferable that a stabilizer is included, and it is more preferable that a basic stabilizer is included since the dihydroxy compound (B) is more likely to be altered under acidic conditions. Basic stabilizers include hydroxides, carbonates, phosphates, phosphites, hypophosphites of group 1 or group 2 metals in the long-period periodic table (Nomenclature of Inorganic Chemistry IUPAC Recommendations 2005). , Borate, fatty acid salt, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, N, N, N-trimethylethanolamine hydroxide (choline), trimethylethylammonium hydroxy , Trimethylbenzylammonium hydroxide, trimethylphenylammonium hydroxide, triethylmethylammonium hydroxide, triethylbenzyl Ruammonium hydroxide, triethylphenylammonium hydroxide, tributylbenzylammonium hydroxide, tributylphenylammonium hydroxide, tetraphenylammonium hydroxide, benzyltriphenylammonium hydroxide, methyltriphenylammonium hydroxide, butyltriphenylammonium hydroxide, etc. Basic ammonium compounds, diethylamine, dibutylamine, triethylamine, morpholine, N-methylmorpholine, pyrrolidine, piperidine, hydroxylamine, 3-amino-1-propanol, ethylenediamine, N-methyldiethanolamine, diethylethanolamine, 4-aminopyridine 2-aminopyridine, N, N-dimethyl-4-aminopyri , Amines such as 4-diethylaminopyridine, 2-hydroxypyridine, 2-methoxypyridine, 4-methoxypyridine, 2-dimethylaminoimidazole, 2-methoxyimidazole, imidazole, 2-mercaptoimidazole, 2-methylimidazole, aminoquinoline And hindered amine compounds such as di- (tert-butyl) amine and 2,2,6,6-tetramethylpiperidine. Among the stabilizers, tetramethylammonium hydroxide, imidazole, and hindered amine stabilizers are preferable from the viewpoint of stabilizing effect.

Although there is no restriction | limiting in particular in content in the dihydroxy compound of these basic stabilizers, since the dihydroxy compound (B) used by this invention is unstable in an acidic state, of the dihydroxy compound (B) containing said stabilizer It is preferable to add a stabilizer so that the pH of the aqueous solution is 7 or more. If the amount is too small, the effect of preventing the alteration of the dihydroxy compound (B) used in the present invention may not be obtained. If the amount is too large, the dihydroxy compound (B) may be modified. It is 0.0001 weight%-1 weight% with respect to the dihydroxy compound (B) used by invention, Preferably it is 0.001 weight%-0.1 weight%.

  In addition, since the dihydroxy compound (B) is easily oxidized by oxygen, in order to prevent decomposition due to oxygen during storage and handling during manufacture, water should not be mixed and an oxygen scavenger is used. Or in a nitrogen atmosphere is essential. When isosorbide is oxidized, decomposition products such as formic acid are generated. For example, when a polycarbonate resin is produced using isosorbide containing these decomposed products, the resulting polycarbonate resin is not only colored but significantly deteriorated in physical properties, and also affects the polymerization reaction, resulting in a high molecular weight polymer. May not be obtained, which is not preferable.

  When these basic stabilizers are included in the dihydroxy compound used in the present invention and used as a raw material for the production of polycarbonate resin, the basic stabilizer itself becomes a polymerization catalyst, which makes it difficult to control the polymerization rate and quality, as well as the resin. The hue will be deteriorated. For this reason, about the thing which has a basic stabilizer among the said dihydroxy compounds (B), it is preferable to remove a basic stabilizer by ion exchange resin, distillation, etc. before using it as a manufacturing raw material of polycarbonate resin.

  In order to obtain the above-mentioned dihydroxy compound (B) that does not contain decomposition products due to oxidation, and in order to remove the aforementioned basic stabilizer, it is preferable to perform 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 distillation purification, when the dihydroxy compound (B) is used as a polycarbonate resin production raw material, it becomes possible to produce a polycarbonate resin excellent in hue and thermal stability without impairing polymerization reactivity.

(Carbonated diester)
In the present invention, the polycarbonate resin can be obtained by polycondensation by a transesterification reaction using the dihydroxy compound containing the dihydroxy compound (A) and the carbonic acid diester as raw materials.
As a carbonic acid diester used, what is represented by following formula (16) is mentioned normally. These carbonic acid diesters may be used alone or in combination of two or more.

（Ａ¹およびＡ²は、それぞれ置換もしくは無置換の炭素数１〜１８の脂肪族炭化水素基または置換もしくは無置換の芳香族炭化水素基であり、Ａ¹とＡ²とは同一であっても異なっていてもよい。Ａ¹およびＡ²の好ましいものは置換もしくは無置換の芳香族炭化水素基であり、より好ましいのは無置換の芳香族炭化水素基である。

(A ¹ and A ² are each a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 18 carbon atoms or a substituted or unsubstituted aromatic hydrocarbon group, and A ¹ and A ² are the same. A ¹ and A ² are preferably a substituted or unsubstituted aromatic hydrocarbon group, and more preferably an unsubstituted aromatic hydrocarbon group.

Examples of the carbonic acid diester represented by the formula (16) include substituted diphenyl carbonates such as diphenyl carbonate (DPC) and ditolyl carbonate, dimethyl carbonate, diethyl carbonate, and di-t-butyl carbonate. Diphenyl carbonate and substituted diphenyl carbonate are preferable, and diphenyl carbonate is particularly preferable. 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.

(Transesterification reaction catalyst)
In the production method of the present invention, the polycarbonate resin is produced by transesterifying the dihydroxy compound containing the dihydroxy compound (A) and the carbonic acid diester represented by the formula (16) as described above. More specifically, it can be obtained by transesterification and removing by-product monohydroxy compounds and the like out of the system. In this transesterification reaction, polycondensation is performed in the presence of the transesterification reaction catalyst. The transesterification reaction catalyst (hereinafter simply referred to as catalyst or polymerization catalyst) that can be used in the production of the polycarbonate resin of the present invention may be used. ) Can significantly affect the reaction rate and the color tone of the polycarbonate resin obtained by polycondensation.

  The catalyst used is not limited as long as it can satisfy the transparency, hue, heat resistance, thermal stability, and mechanical strength of the produced polycarbonate resin. Examples include basic compounds such as metal compounds of group (hereinafter simply referred to as “Group 1” and “Group 2”), basic boron compounds, basic phosphorus compounds, basic ammonium compounds, and amine compounds. Preferably, Group 1 metal compounds and / or Group 2 metal compounds are used.

  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, and carbonic acid. Lithium, cesium carbonate, sodium acetate, potassium acetate, lithium acetate, cesium acetate, sodium stearate, potassium stearate, lithium stearate, cesium stearate, sodium borohydride, potassium borohydride, lithium borohydride, hydrogenated Cesium boron, sodium tetraphenylborate, potassium tetraphenylborate, lithium tetraphenylborate, cesium tetraphenylborate, sodium benzoate, potassium benzoate, lithium benzoate, cesium benzoate , 2 sodium hydrogen phosphate, 2 potassium hydrogen 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, cesium alcoholate, phenolate, disodium salt of bisphenol A, 2 potassium salt, 2 lithium salt, 2 cesium salt, etc., among others, from the viewpoint of polymerization activity and the hue of the polycarbonate resin obtained, Lithium compounds are preferred.

  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, carbonic acid. Magnesium, strontium carbonate, calcium acetate, barium acetate, magnesium acetate, strontium acetate, calcium stearate, barium stearate, magnesium stearate, strontium stearate, etc. Among them, magnesium compound, calcium compound, barium compound are preferable, polymerization activity From the viewpoint of the hue of the obtained polycarbonate resin, a magnesium compound and / or a calcium compound is more preferable.

In addition, a basic compound such as a basic boron compound, a basic phosphorus compound, a basic ammonium compound, and an amine compound can be used in combination with the aforementioned Group 1 metal compound and / or Group 2 metal compound. However, it is preferable to use only a Group 1 metal compound and / or a Group 2 metal compound, and particularly preferable is at least one metal compound selected from the group consisting of a Group 2 metal and lithium.

  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 Dorokishido, 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, and 4-methoxypyridine. , 2-dimethylaminoimidazole, 2-methoxyimidazole, imidazole, 2-mercaptoimidazole, 2-methylimidazole, aminoquinoline, guanidine and the like.

  The amount of the polymerization catalyst used is preferably 0.1 μmol to 300 μmol, preferably 0.5 μmol to 100 μmol per 1 mol of all dihydroxy compounds used in the polymerization, and more particularly than the group consisting of Group 2 in the long-period periodic table and lithium When using a compound containing at least one selected metal, particularly when using a magnesium compound and / or a calcium compound, the amount of the metal is preferably 0.1 μmol or more per 1 mol of the total dihydroxy compound, and preferably 0.8. 3 μmol or more, particularly preferably 0.5 μmol or more. The upper limit is preferably 20 μmol or less, preferably 10 μmol or less, more preferably 3 μmol or less, and particularly preferably 1.5 μmol or less. However, the dihydroxy compound (A) having a fluorene moiety used in the present invention may contain sulfur impurities derived from the catalyst used in the synthesis, and has the effect of deactivating the polymerization catalyst. The polymerization catalyst to be actually added needs to be used in excess of the above range as much as it is deactivated. When the total sulfur element content per 1 mol of all dihydroxy compounds used in the reaction is P [μmol] and the amount of metal element of the polymerization catalyst is Q [μmol], it is preferably within the range of the following formula (17).

0.1 ≦ Q / P ≦ 2 (17)
If the amount of the catalyst is too small, the polymerization rate is slowed down. Therefore, in order to obtain a polycarbonate resin having a desired molecular weight, the polymerization temperature must be increased accordingly. Therefore, there is a high possibility that the hue of the obtained polycarbonate resin is deteriorated, and the unreacted raw material volatilizes during the polymerization, and the molar ratio of the dihydroxy compound and the carbonic acid diester collapses, and the desired molecular weight may not be reached. There is sex. On the other hand, if the amount of the polymerization catalyst used is too large, undesirable side reactions may occur, which may lead to deterioration of the hue of the obtained polycarbonate resin and coloring of the resin during molding.

However, sodium, potassium, and cesium among Group 1 metals may adversely affect the hue when contained in the polycarbonate resin. And these metals may mix not only from the catalyst to be used but from a raw material or a reaction apparatus. Regardless of the source, the total amount of these metal compounds in the polycarbonate resin is preferably 2 μmol or less, preferably 1 μmol or less, more preferably 0.5 μmol or less, per 1 mol of the total dihydroxy compound as the metal amount.

The molecular weight of the polycarbonate resin obtained by polycondensation in this way can be expressed in terms of reduced viscosity, preferably 0.20 dL / g or more, preferably 0.30 dL / g or more, It is good that it is 0.000 dL / g or less, preferably 0.80 dL / g or less, and more preferably 0.70 dL / g or less. If the reduced viscosity of the polycarbonate resin is too low, the mechanical strength of the molded product may be lowered. If it is too large, the fluidity at the time of molding is lowered, and the productivity and moldability tend to be lowered. The reduced viscosity is a value measured using an Ubbelohde viscometer at a temperature of 20.0 ° C. ± 0.1 ° C., prepared precisely using a methylene chloride as a solvent and a polycarbonate resin concentration of 0.6 g / dL. It is.
Similarly, the melt viscosity of the polycarbonate resin obtained by the method of the present invention is preferably 1000 Pa · s or more and 4000 Pa · s or less at a temperature of 240 ° C. and a shear rate of 91.2 sec ⁻¹ . Furthermore, it is preferably 1200 Pa · s or more and 3800 Pa · s or less, and particularly preferably 1500 Pa · s or more and 3500 Pa · s or less. In the present specification, the melt viscosity is measured using a capillary rheometer (manufactured by Toyo Seiki Co., Ltd.).

  The glass transition temperature of the polycarbonate resin produced by the method of the present invention is preferably 100 ° C to 160 ° C, more preferably 110 ° C to 150 ° C, still more preferably 115 ° C to 145 ° C, and 118 ° C to 142 ° C. Particularly preferred. If the glass transition temperature is excessively low, the heat resistance tends to deteriorate, and there is a possibility of causing a dimensional change after film formation. Moreover, when polycarbonate resin is used as a retardation film and laminated with a polarizing plate, the image quality may be lowered. On the other hand, if the glass transition temperature is excessively high, unevenness of the film thickness may occur at the time of film forming, the film may become brittle, and the molding stability may deteriorate, and the transparency of the film may be impaired. is there.

  Further, the polycarbonate resin obtained by the method of the present invention includes, for example, aromatic polycarbonate, aromatic polyester, aliphatic polyester, polyamide, polystyrene, polyolefin, acrylic, 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.

  Before performing various moldings, the polycarbonate resin produced by the method of the present invention is optionally provided with a heat stabilizer, a neutralizing agent, an ultraviolet absorber, a release agent, an antistatic agent, a lubricant, a lubricant, Additives such as plasticizers and compatibilizers can also be mixed with a tumbler, super mixer, floater, V-type blender, nauter mixer, Banbury mixer, extruder or the like.

  As a method for producing a film using the polycarbonate resin produced by the method of the present invention, a melt extrusion method is preferred from the viewpoint of productivity. In the melt extrusion method, a method of extruding a resin using a T die and sending it to a cooling roll is preferably used. The melting temperature at this time is determined from the molecular weight, Tg, melt flow characteristics, etc. of the polycarbonate resin, but is in the range of 150 ° C. to 300 ° C., more preferably in the range of 170 ° C. to 280 ° C. If the temperature is too high, problems such as coloring due to thermal degradation, appearance defects due to the generation of foreign matter and silver, and die lines from the T die are likely to occur. If the temperature is too low, the viscosity increases, and polymer orientation and stress strain tend to remain. The retardation value of the formed film is preferably 20 nm or less, more preferably 10 nm or less. If the retardation value of the film is too large, it is not preferable because when the film is stretched to obtain a retardation film, dispersion of the retardation value in the film surface increases.

  A solution casting method can also be used as a method for producing the film. As the solvent, methylene chloride, chloroform, 1,2-dichloroethane, 1,1,2,2-tetrachloroethane, dioxolane, dioxane, tetrahydrofuran, toluene, methyl ethyl ketone and the like are preferably used. The amount of residual solvent in the film obtained by the solution casting method is preferably 2% by weight or less, more preferably 1% by weight or less. When the amount of residual solvent is 2% by weight or more, the glass transition temperature of the film is remarkably lowered, which is not preferable from the viewpoint of heat resistance.

  As thickness of the said film, the range of 20 micrometers-400 micrometers is preferable, More preferably, it is the range of 30 micrometers-300 micrometers. In the case where such a film is further stretched to obtain a retardation film, a desired retardation value and thickness of the retardation film may be taken into consideration and appropriately determined within the above range.

  A retardation film can be obtained by stretching and orienting the unstretched film thus obtained. As the stretching method, a known method such as longitudinal uniaxial stretching, lateral uniaxial stretching using a tenter or the like, or simultaneous biaxial stretching or sequential biaxial stretching in combination thereof can be used. Stretching may be performed batchwise, but it is preferable in terms of productivity to be performed continuously. Further, a continuous retardation film with less variation in retardation within the film surface can be obtained compared to a batch system. The stretching temperature is in the range of (Tg-20 ° C) to (Tg + 30 ° C), preferably in the range of (Tg-10 ° C) to (Tg + 20 ° C) with respect to the glass transition temperature of the polycarbonate resin. Although the draw ratio is determined by the target retardation value, it is 1.05 to 4 times, more preferably 1.1 to 3 times, respectively in the longitudinal and lateral directions.

The transparent film formed by molding the polycarbonate resin produced by the method of the present invention preferably has a birefringence of 0.0010 or more, and more preferably 0.0014 or more. When the above transparent film is a retardation film, the retardation is proportional to the thickness. Therefore, if the birefringence is excessively small, the film thickness must be increased in order to develop the same retardation, and the thin film is thin. May not be compatible with the equipment. In addition, the said birefringence is the value which measured the transparent film uniaxially stretched by the fixed end at the glass transition temperature +15 degreeC extending | stretching temperature of polycarbonate resin manufactured by the method of this invention.
The retardation film according to the present invention is used as a retardation plate for various liquid crystal display devices or organic EL display devices by laminating and bonding a known iodine-based or dye-based polarizing plate and an adhesive. Can be used.

  In the transparent film according to the present invention, the ratio of the retardation (Re450) measured at a wavelength of 450 nm to the retardation (Re550) measured at a wavelength of 550 nm is preferably 0.50 to 1.0, and 0.80 to 0.00. 95 is more preferable. When the ratio is within this range, ideal phase difference characteristics can be obtained at each wavelength in the visible region. For example, a retardation film having such wavelength dependency as a quarter wavelength plate is prepared and bonded to a polarizing plate, whereby a circular polarizing plate or the like can be prepared, and a polarizing plate with less hue wavelength dependency In addition, a display device can be realized. On the other hand, when the ratio is out of this range, the wavelength dependence of the hue is increased, optical compensation is not performed at all wavelengths in the visible region, and coloring and contrast due to light passing through the polarizing plate and the display device are lost. Problems such as degradation occur.

The transparent film according to the present invention preferably has a photoelastic coefficient of 50 × 10 ⁻¹² Pa ⁻¹ or less, and more preferably 40 × 10 ⁻¹² Pa ⁻¹ or less. When the photoelastic coefficient is excessively large, when a retardation film is used, there is a possibility that image quality is deteriorated such that the periphery of the screen is blurred in white when pasted to a polarizing plate. This problem is particularly noticeable when used in large display devices.

  The retardation film according to the present invention is for viewing angle compensation of various displays (liquid crystal display device, organic EL display device, plasma display device, FED field emission display device, SED surface electric field display device), antireflection of external light, color It can be used for compensation, conversion of linearly polarized light into circularly polarized light, and the like.

  As the liquid crystal display device, a reflective liquid crystal display device including a reflective liquid crystal panel is preferable. A reflective liquid crystal display device comprising a polarizing film, a quarter-wave plate, and a liquid crystal cell including a liquid crystal layer between two substrates having transparent electrodes in this order. A display device with excellent image quality can be obtained by using it for a display device, particularly a polarizing film single-reflection type liquid crystal display device. This reflective liquid crystal display device is composed of a polarizing film, a retardation film, a substrate with a transparent electrode, a liquid crystal layer, a substrate with a scattering reflection electrode, a polarizing film, a scattering plate, a retardation film, and a transparent electrode. A substrate, a liquid crystal layer, a substrate with a mirror reflective electrode, a polarizing film, a retardation film, a substrate with a transparent electrode, a liquid crystal layer, a substrate with a transparent electrode, and a reflective layer. . Further, the quarter-wave plate can be used in a liquid crystal display device having both a transmission type and a reflection type. Examples of the configuration of the liquid crystal display device include a polarizing film, a retardation film, a substrate with a transparent electrode, a liquid crystal layer, a substrate with a reflection / transmission electrode, a retardation film, a polarizing film, and a backlight system. Furthermore, for example, in a reflective polarizing film made of cholesteric liquid crystal that reflects only the left or right circularly polarized light, if the circularly polarized light is converted into linearly polarized light, good linearly polarized light can be obtained in a wide band.

  The polycarbonate resin according to the present invention has low birefringence, excellent heat resistance and moldability, and also has little transparency and high transparency. Therefore, it is used for other optical films, optical disks, optical prisms, pickup lenses, and the like. You can also.

The abbreviations of the compounds used in the description of the following examples are as follows.
BHEPF: 9,9-bis (4- (2-hydroxyethoxy) phenyl) fluorene (Osaka Gas Chemical Co., Ltd., trade name: BPEF, median diameter 57 μm)
・ ISB: Isosorbide (Rocket Fleure, trade name: POLYSORB PS) ・ DEG: Diethylene glycol (Mitsubishi Chemical Corporation)
・ DPC: Diphenyl carbonate (Mitsubishi Chemical Corporation)

  The composition analysis and physical property evaluation of the reaction solution and the polycarbonate resin were performed by the following methods.

1) Content of monohydroxy compound (phenol) in the reaction solution About 0.5 g of a sample was precisely weighed and dissolved in 5 mL of methylene chloride, and then acetone was added so that the total amount was 25 mL. The solution was filtered through a 0.2 μm disk filter, and the amount of phenol was determined by liquid chromatography, and then the content was calculated. The equipment and conditions used are as follows.
・ Device: manufactured by Shimadzu Corporation System controller: CBM-20A
Pump: LC-10AD
Column oven: CTO-10ASvp
Detector: SPD-M20A
Analytical column: Cadenza CD-18 4.6 mmΦ × 250 mm
Oven temperature: 40 ° C
・ Detection wavelength: 220 nm
Eluent: Liquid A: 0.1% phosphoric acid aqueous solution, Liquid B: acetonitrile A / B = 40/60 (vol%) to A / B = 0/100 (vol%) in 10 minutes Gradient Flow rate: 1mL / min
Sample injection volume: 10 μL

2) Reduced viscosity (η _sp / C)
Using methylene chloride as a solvent, a polycarbonate solution having a concentration of 0.6 g / dL was prepared. Using a Ubbelohde type viscosity tube manufactured by Moriyu Rika Kogyo Co., Ltd., measurement is performed at a temperature of 20.0 ° C. ± 0.1 ° C., and a relative viscosity η _rel is obtained from the following equation from the solvent passage time t ₀ and the solution passage time t. , Η _rel = t / t _{0 The} specific viscosity ηsp was determined from the following equation using the relative viscosity. η _sp = (η−η ₀ ) / η ₀ = η _rel −1 The specific viscosity was divided by the concentration C (g / dL) to obtain the reduced viscosity. The higher this value, the higher the molecular weight. 3) Melt viscosity of polycarbonate resin The polycarbonate resin used for the measurement was vacuum-dried at 80 ° C for 5 hours or more before the measurement.
Using a Capillograph manufactured by Toyo Seiki Co., Ltd., the melt viscosity at a temperature of 240 ° C. and a shear rate of 91.2 sec ⁻¹ was measured using a die having a diameter of 1 mm × length of 10 mm.

4) YI value of polycarbonate resin The hue of the polycarbonate resin was evaluated by measuring the YI value (yellow index value) in the reflected light of the polycarbonate pellets in accordance with ASTM D1925. As the apparatus, a spectrocolorimeter CM-5 manufactured by Konica Minolta Co., Ltd. was used, and the measurement conditions were a measurement diameter of 30 mm and SCE. Petri dish calibration glass CM-A212 was fitted into the measurement part, and zero calibration was performed by placing a zero calibration box CM-A124 thereon, followed by white calibration using a built-in white calibration plate. Measurement was performed using a white calibration plate CM-A210. L * was 99.40 ± 0.05, a * was 0.03 ± 0.01, b * was −0.43 ± 0.01, and YI was −. It was confirmed to be 0.58 ± 0.01. The pellets were measured by packing them into a cylindrical glass container having an inner diameter of 30 mm and a height of 50 mm to a depth of about 40 mm. The operation of taking out the pellet from the glass container and then performing the measurement again was repeated twice, and the average value of the measurement values of three times in total was used. The smaller the YI value, the less yellow the resin is, and the better the color tone.

5) Quantitative determination of foreign matter in polycarbonate resin The barrel set temperature of a 20 mm diameter single screw extruder equipped with a T die was set to 210 ° C, 220 ° C, 230 ° C, 230 ° C, 220 ° C from the pellet supply side, and the cooling roll was A film having a thickness of 35 μm ± 5 μm was formed using an optical control system (Film Quality Testing System (model FSA100)), and the number of foreign matters of 25 μm or more per 1 m ² was measured.
6) Phase difference and wavelength dispersion of phase difference 4.0 g of polycarbonate resin sample vacuum-dried at 80 ° C. for 5 hours was heated by a hot press using a spacer having a width of 8 cm, a length of 8 cm and a thickness of 0.5 mm. After pressurizing for 1 minute at a press temperature of 250 ° C. under preheating for 1 minute and a pressure of 20 MPa, the spacers are taken out, and cooled with a water tube cooling press for 3 minutes at a pressure of 20 MPa to produce a film, width 6 cm, length A 6 cm sample was cut out. This sample was stretched with a batch-type biaxial stretching apparatus (manufactured by Toyo Seiki Sangyo Co., Ltd.) at a stretching temperature of glass transition temperature of polycarbonate resin + 15 ° C. and a stretching speed of 720 mm / min (strain rate of 1200% / min). Uniaxial stretching was performed at a magnification of 2.0. At this time, it extended | stretched in the perpendicular | vertical direction with respect to the extending | stretching state in the hold | maintained state (drawing ratio 1.0).
Cut out to 4 cm in width and 4 cm in length from the stretched sample, and measure the phase difference at a measurement wavelength of 450, 500, 550, 590, and 630 nm using a phase difference measuring device (KOBRA-WPR manufactured by Oji Scientific Instruments). The wavelength dispersion was measured. For the wavelength dispersion, the ratio (Re450 / Re550) of the phase differences Re450 and Re550 measured at 450 nm and 550 nm was calculated. If the phase difference ratio is greater than 1, the chromatic dispersion is positive, and if it is less than 1, it is negative. It is shown that the smaller the ratio of the respective phase differences is less than 1, the stronger the negative wavelength dispersion.

[ Reference Example 1]
As shown in FIG. 1 described above, a polycarbonate resin was produced under the following conditions using a continuous production apparatus having three vertical stirring reactors and one horizontal stirring reactor. First, as shown in Table 1, each reactor was set in advance to the reaction solution temperature and pressure according to the reaction conditions. Next, a specific molar ratio of BHEPF, ISB, DEG, and DPC (BHEPF / ISB / DEG / DPC = 0.348 / 0.490 / 0.162 / 1. 000) and heated to 120 ° C. to obtain a raw material mixed melt.

Subsequently, the raw material mixed melt is continuously supplied into the first vertical stirring reaction tank 6a controlled within a range of ± 5% of the predetermined temperature and pressure described above via a raw material introduction pipe heated to 140 ° C. did. The flow rate was set so that the theoretically produced polymer amount was 50 kg / hr.
The liquid level is kept constant while controlling the opening of a valve (not shown) provided in the polymer discharge line at the bottom of the tank so that the average residence time of the first vertical stirring reaction tank 6a is 80 minutes. It was. Simultaneously with the start of the supply of the raw material mixed melt, an aqueous magnesium acetate solution as a catalyst was continuously supplied into the first vertical stirring reaction tank 6a from the catalyst supply port 1d at a ratio of 10 μmol with respect to 1 mol of all dihydroxy components.

The polymerization reaction liquid discharged from the bottom of the first vertical stirring reaction tank 6a continues to the second vertical stirring reaction tank 6b, the third vertical stirring reaction tank 6c, and the fourth horizontal stirring reactor 6d (biaxial). Glasses blades, L / D = 4) were sequentially and continuously supplied. During the polymerization reaction, the liquid level of each reactor was controlled so that the average residence time shown in Table 1 was obtained.
The reaction liquid between the first reactor and the fourth reactor was sampled from a valve provided in a pipe connecting the reactors.

  The molten polycarbonate resin extracted from the fourth horizontal stirring reactor 6d was transferred to the extruder 15a by the gear pump 4c. The extruder (manufactured by Nippon Steel Works: twin screw extruder TEX30α: L / D = 42) had three vent ports and was devolatilized from the vent ports using a vacuum pump. At this time, the pressure in the vent portion was 1 kPa or less in absolute pressure. When the number of rotations of the screw was lowered to such an extent that the resin did not roll up at the vent port, 180 rpm was the limit. In this state, the cylinder temperature was lowered to the allowable range of the motor load and set to 230 ° C.

In Reference Example 1, the discharge side gear pump 4d and the polymer filter 15b of the extruder 15a were not installed, and a die for stranding the resin after passing through the extruder was mounted. The discharged resin was cooled with water and solidified in the form of a strand, and then pelletized with a rotary cutter. The process from stranding to pelletization was performed in a clean room. Subsequently, the pellets were sent to the product hopper 16d by pneumatic transfer.

During the production of the polycarbonate resin, the reaction solution corresponding to the outlet of the final polymerization reactor is sampled from the valve attached after the gear pump 4c, and the polycarbonate pellets are sampled after the strand cutter 16b. did.
The residence time of the piping was calculated from the volume of the piping at each location and the flow rate of the reaction solution or molten polycarbonate resin. Since the temperature of the piping from the first reactor to the front of the extruder was the highest at the outlet of each piping, the temperature at the piping outlet was used for the calculation. Since the temperature at the pipe inlet (extruder outlet) reached the highest in the pipes after the extruder, the temperature at the pipe inlet was used for the calculation.
The results are summarized in Table 2.

[ Reference Example 2]
The same procedure as in Reference Example 1 was carried out except that no extruder was used. Compared to Reference Example 1, since the monohydroxy compound was not volatilized, the content of the monohydroxy compound increased. It can be seen that the monohydroxy compound is increased before the polycarbonate resin is taken out from the outlet of the final polymerization reactor. However, since the residence time was short, the obtained polycarbonate resin had low YI and good quality.

[ Reference Example 3]
The reaction was performed in the same manner as in Reference Example 1 except that the reaction liquid temperature in the first vertical stirring reaction tank 6a was 210 ° C. and the reaction liquid temperature in the second vertical stirring reaction tank 6b was 210 ° C. Although the color tone was slightly deteriorated as compared with Reference Example 1, the quality of the obtained polycarbonate resin was good.

[Example 1 ]
A gear pump 4d is disposed on the resin discharge side of the extruder 15a, and further downstream, a leaf disk filter (made by Nippon Pole Co., Ltd.) having an outer diameter of 112 mm, an inner diameter of 38 mm, and a filtration accuracy of 99% within the containment vessel. The polymer filter 15b equipped with 10 sheets) was disposed. A die for forming a strand was attached to the discharge side of the polymer filter. Otherwise, the same procedure as in Reference Example 1 was performed.
Considering the torque limit of the gear pump 4d and the pressure resistance of the polymer filter, the temperature setting of the polymer filter was 240 ° C.
Compared to Reference Example 1, the amount of foreign matter in the polycarbonate resin was reduced. On the other hand, since the residence time in the polymer filter was added, the color tone was slightly deteriorated and the content of the monohydroxy compound was increased, but the quality of the obtained polycarbonate resin was good.

[Example 2 ]
The flow rate of the raw material mixed melt supplied to the first reactor was set so that the theoretical polymer amount was 70 kg / hr. The screw speed of the extruder and the temperature setting of the polymer filter were adjusted in the same manner as described above, the screw speed was 252 rpm, and the temperature of the polymer filter was 240 ° C. Except for the above, the same procedure as in Example 1 was performed.
The color tone of the obtained polycarbonate resin was very good and the amount of foreign matter was reduced. The reason for the improved color tone is thought to be that the residence time in each pipe or polymer filter was shortened.

[Comparative Example 1]
The flow rate of the raw material mixed melt supplied to the first reactor was set so that the theoretical polymer amount was 30 kg / hr. The screw speed of the extruder and the temperature setting of the polymer filter were adjusted in the same manner as described above, the screw speed was 108 rpm, and the temperature of the polymer filter was 240 ° C. Except for the above, the same procedure as in Example 1 was performed.
The color tone of the obtained polycarbonate resin deteriorated, resulting in poor quality. Moreover, the content of monohydroxy compounds also increased. Since the flow rate of the reaction solution or the molten polycarbonate resin is reduced, the residence time in each pipe or polymer filter is increased, which is considered to be a cause of thermal deterioration in the pipe.

[Comparative Example 2]
The same procedure as in Example 1 was performed except that the screw speed of the extruder was changed to 230 rpm.
The color tone of the obtained polycarbonate resin deteriorated significantly, resulting in poor quality. Moreover, the content of monohydroxy compounds also increased. In general, the higher the screw speed of the extruder, the better the devolatilization efficiency. However, when the polymer filter is used in combination, the resin temperature rises due to shear heat generation when the screw speed is increased. Since it stays at a higher temperature, the amount of monohydroxy compounds generated by thermal decomposition has increased.

[Comparative Example 3]
Table 2 shows production examples of conventional aromatic polycarbonate resins using bisphenol A as a monomer.

[Summary]
As shown in the results of Table 2, by setting the heat history in the pipe within a predetermined range, it is possible to improve a plurality of qualities of the polycarbonate resin such as color tone and residual amount of monohydroxy compound. Furthermore, by using an extruder or a filter under the condition of suppressing thermal deterioration, it is possible to reduce foreign matter to a level that does not cause a problem in optical applications while maintaining the color tone.

1a Raw material (carbonic acid diester) supply port 1b, 1c, 1d Raw material (dihydroxy compound) supply port 1e Catalyst supply port 2a Raw material mixing tank 3a Anchor type stirring blade 4a Raw material supply pump 4b, 4c, 4d Gear pump 5a Raw material filter 6a Type stirring reaction tank 6b second vertical stirring reaction tank 6c third vertical stirring reaction tank 6d fourth horizontal stirring reactor 7a, 7b, 7c max blend blade 7d biaxial glasses type stirring blade 8a, 8b internal heat exchanger 9a , 9b Reflux coolers 10a, 10b Reflux pipes 11a, 11b, 11c, 11d Distillate pipes 12a, 12b, 12c, 12d Condensers 13a, 13b, 13c, 13d Depressurizer 14a Distillate recovery tank 15a Twin screw extruder 15b Polymer filter 16a Strand cooling tank 16b Strand cutter 16c Air blower 16d Product hopper 16e meter 16f product bag (paper bag, such as a flexible container)

Claims (11)

A method for producing a polycarbonate resin by continuously supplying a dihydroxy compound containing a dihydroxy compound (A) having a fluorene structure (A), a carbonic acid diester, and a polymerization catalyst to a reactor and performing polycondensation,
A plurality of the reactors are connected in series at least, and the reaction liquid in each pipe between the first reactor among the reactors connected to the plurality of reactors and the step of taking out the polycarbonate resin, or and residence time of the molten polycarbonate resin, the temperature defined by T _i in each pipe meets the following formula (1),
Supplying the polycarbonate resin obtained by the polycondensation to an extruder in a molten state without solidifying,
A method for producing a polycarbonate resin, comprising a step of supplying and filtering the polycarbonate resin obtained by the polycondensation to a filter in a molten state without solidifying .

T _i : Temperature [K], whichever is the higher of the temperature of the reaction liquid or molten polycarbonate resin at the inlet of the pipe i and the temperature of the reaction liquid or molten polycarbonate resin at the outlet
θ _i : Residence time in pipe i [min]   The method for producing a polycarbonate resin according to claim 1, wherein the residence time until the polycarbonate resin is taken out from the outlet of the final polymerization reactor is within 30 minutes. When transferring a reaction liquid containing 6 wt% or more of the produced monohydroxy compound, the reaction liquid temperature in the pipe is 210 ° C. or lower, and when transferring a reaction liquid containing 3 wt% or more and less than 6 wt%, The method for producing a polycarbonate resin according to claim 1 or 2, wherein the reaction liquid temperature is 220 ° C or lower, and the reaction liquid temperature in the pipe is 230 ° C or lower when transferring a reaction liquid contained in an amount of 1 wt% or more and less than 3 wt%. . When the amount of the monohydroxy compound in the polycarbonate resin at the outlet of the final polymerization reactor is A [ppm] and the content of the monohydroxy compound in the obtained polycarbonate resin is B [ppm], the following formula (6) is satisfied. The manufacturing method of the polycarbonate resin of any one of Claims 1 thru | or 3.
A-B ≧ 100 (6)   The method for producing a polycarbonate resin according to any one of claims 1 to 4, wherein the polymerization catalyst is at least one metal compound selected from the group consisting of metals of Group 2 of the long-period periodic table and lithium. The method for producing a polycarbonate resin according to any one of claims 1 to 5, wherein the dihydroxy compound (A) is a dihydroxy compound represented by the following structural formula (11).

(In the general formula (11), R ^{1 to} R ⁴ are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted carbon number 6 to 20 carbon atoms. Or a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, X is a substituted or unsubstituted alkylene group having 2 to 10 carbon atoms, substituted or unsubstituted carbon number A cycloalkylene group having 6 to 20 carbon atoms or a substituted or unsubstituted arylene group having 6 to 20 carbon atoms, m and n are each independently an integer of 0 to 5). 7. The method according to claim 1, wherein at least the dihydroxy compound (A) and one or more dihydroxy compounds (B) having a site represented by the following formula (12) are used as raw materials. A method for producing a polycarbonate resin.

(However, in the case moiety represented by the above formula (12) is a portion constituting a part of -CH ₂ -OH, if the dihydroxy compound (B) is the (11) compound represented by the formula except for.)   The method for producing a polycarbonate resin according to claim 7, wherein the dihydroxy compound (B) is a compound having a cyclic ether structure. The method for producing a polycarbonate resin according to claim 8, wherein the dihydroxy compound (B) is a compound represented by the following structural formula (13).

10. The method for producing a polycarbonate resin according to claim 1, wherein the obtained polycarbonate resin has a melt viscosity at a temperature of 240 ° C. and a shear rate of 91.2 sec ⁻¹ of 1000 Pa · s or more and 4000 Pa · s or less. . Polycondensation by the obtained polycarbonate resin, or a polycarbonate resin was filtered by a filter in a molten state, discharged from the die head in the form of a strand, cooled, claims 1 to 10 comprising the step of pelletizing with cutter The manufacturing method of polycarbonate resin of any one of these.

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