JP2013221146A - Method for producing polycarbonate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing polycarbonate with excellent characteristics such as hues, mechanical properties, and thermal stability by using a predetermined dihydroxy compound with low thermal stability.SOLUTION: A method for producing polycarbonate is a method to produce polycarbonate by continuously supplying a predetermined dihydroxy compound, a carbonic acid diester, and a polymerization catalyst to reactors, wherein residence time of a reaction liquid or molten polycarbonate in respective pipes between the first reactor, of at least two or more reactors connected with one another in series, and a step to take out polycarbonate, and temperatures in respective pipes satisfy formula (2) (wherein Tis a temperature (K) of a higher one of either a temperature of the reaction liquid or the molten polycarbonate at an inlet of a pipe i, or a temperature of the reaction liquid or the molten polycarbonate at an outlet; and θ: residence time (min) in the pipe i).

Description

  The present invention relates to a method for efficiently and stably producing a polycarbonate having excellent transparency, hue, heat resistance, thermal stability, light resistance, mechanical strength and the like and having few foreign matters, and a polycarbonate obtained by the production method. It provides pellets.

  Polycarbonate is generally composed of bisphenols as monomer components, making use of superiority such as transparency, heat resistance and mechanical strength, so-called engineering in the optical field such as electrical / electronic parts, automotive parts, optical recording media, and lenses. Widely used as plastic.

  Conventional polycarbonates are manufactured using raw materials derived from petroleum resources. However, in recent years, there is a concern about the exhaustion of petroleum resources, and there is a need to provide polycarbonates using raw materials obtained from biomass resources such as plants. ing. In addition, since there is a concern that global warming due to the increase and accumulation of carbon dioxide emissions will lead to climate change, even if it is disposed of after use, the polycarbonate Development is required.

  Under such circumstances, there is a method for obtaining polycarbonate while isosorbide (ISB), which is a dihydroxy compound obtained from biomass resources, is used as a monomer component and the monohydroxy compound by-produced is distilled off under reduced pressure by transesterification with a carbonic acid diester. It has been proposed (see, for example, Patent Documents 1 to 6). Moreover, it is known that the polycarbonate obtained from ISB has excellent optical properties and can be usefully used as an optical material.

  However, a dihydroxy compound such as ISB has a lower thermal stability than bisphenols, and there is a problem that the resin is colored due to thermal decomposition during a 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 less heat history using a continuous polymerization process has been proposed (see Patent Document 7).

International Publication No. 04/111106 Pamphlet Japanese Patent Laid-Open No. 2006-232897 JP 2006-28441 A JP 2008-24919 A JP 2009-91404 A JP 2009-91417 A JP 2009-161745 A

  In the continuous polymerization process, piping that connects 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 resulting polycarbonate. Was found. Furthermore, a problem has also been found in which the polycarbonate melted after the final reactor stays in the pipe, whereby the polymerization reaction and thermal decomposition progress, and the residual low molecular components in the resin increase.

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

Therefore, the present invention solves the above-described multiple problems in the production of a polycarbonate using a specific dihydroxy compound having a —CH ₂ —O— structure, which has lower thermal stability than conventional bisphenols, Another object of the present invention is to provide a method for producing a polycarbonate having excellent properties such as mechanical properties and thermal stability.

（但し、上記式（１）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
を除く。）

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］最終反応器の出口からポリカーボネートが常温下に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の製造方法。
［３］前記反応器には、反応副生物であるモノヒドロキシ化合物を脱揮除去する配管が接
続され、炭酸ジエステルより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の内温を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の内温を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の内温を２３０℃以下とする［１］又は［２］に記載のポリカーボネートの製造方法。
［４］得られるポリカーボネートが、温度２４０℃、剪断速度９１．２ｓｅｃ^-1における溶融粘度が７００Ｐａ・ｓ以上、３５００Ｐａ・ｓ以下である［１］乃至［３］のいずれか１項に記載のポリカーボネートの製造方法。
［５］前記最終反応器の出口における溶融ポリカーボネート樹脂中の全ヒドロキシ末端基の量が５ｍｏｌ／ｔｏｎ以上６０ｍｏｌ／ｔｏｎ以下である［１］乃至［４］のいずれか１項に記載のポリカーボネートの製造方法。
［６］前記最終反応器出口における溶融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（５）を満たす［１］乃至［５］のいずれか１項に記載のポリカーボネートの製造方法。
Ａ−Ｂ ≧ １００ （５）
［７］前記最終反応器の出口のポリカーボネート中における二重結合末端構造の量をＰ（ｍｏｌ／ｔｏｎ）、最終的に得られるポリカーボネート中の二重結合末端構造の量をＱ（ｍｏｌ／ｔｏｎ）とした場合に、下記式（６）を満たす［１］乃至［６］のいずれか１項に記載のポリカーボネートの製造方法。
Ｑ−Ｐ ≦ １０ （６）
［８］前記重合触媒が、長周期型周期表第２族の金属からなる群及びリチウム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［７］のいずれか１項に記載のポリカーボネートの製造方法。
［９］前記式（１）で表される部位を有する特定ジヒドロキシ化合物が、環状エーテル構造を有する化合物である［１］乃至［８］のいずれか１項に記載のポリカーボネートの製造方法。
［１０］前記式（１）で表される部位を有する特定ジヒドロキシ化合物は、下記構造式（１２）で表される化合物である［９］に記載のポリカーボネートの製造方法。

［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１項に記載のポリカーボネートの製造方法。
［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１項に記載のポリカーボネートの製造方法。
［１３］重縮合により得られたポリカーボネート、又は、それをフィルターで濾過した樹脂を、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１項に記載のポリカーボネートの製造方法。
［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時、該フィルムに含まれる最大長２
５μｍ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 repeated studies by the present inventors to solve the above-mentioned problems, in the method for producing a polycarbonate by polycondensation of a dihydroxy compound and a carbonic acid diester, the internal temperature and stagnation of the piping for transferring the reaction liquid or molten polycarbonate By setting the parameters related to the heat history represented by time within the specified range, it is possible to efficiently and stably produce polycarbonate with excellent transparency, hue, heat resistance, thermal stability, mechanical strength, etc. As a result, the present invention has been completed. That is, the gist of the present invention resides in the following [1] to [15]. [1] A dihydroxy compound containing a specific dihydroxy compound having a site represented by the following formula (1) as part of the structure, a carbonic acid diester, and a polymerization catalyst are continuously supplied to a reactor, and polycondensed to form a polycarbonate. A plurality of the reactors connected in series, and each of the reactors between the first reactor of the reactors connected to the plurality of reactors and the step of taking out the polycarbonate. polycarbonate production method temperature defined by T _i in residence time and the pipes of the reaction solution or melt polycarbonate in the pipe satisfies the following equation (2).

(However, the site represented by the above formula (1) unless a portion constituting a part of -CH ₂ -OH.)

T _i : Temperature of the reaction liquid or molten polycarbonate at the inlet of the pipe i and the temperature of the reaction liquid or molten polycarbonate at the outlet, whichever is higher [K] θ _i : Residence time [min] in the pipe i
[2] The method for producing a polycarbonate according to [1], wherein a residence time until the polycarbonate is taken out from the outlet of the final reactor at room temperature is within 30 minutes.
[3] A pipe for devolatilizing and removing the monohydroxy compound as a reaction byproduct is connected to the reactor, and a pipe for transferring a reaction solution containing 6 wt% or more of a monohydroxy compound generated from a carbonic acid diester is used. When transporting a reaction solution containing 3 wt% or more and less than 6 wt% with an internal temperature of 210 ° C or less When transferring a reaction solution containing 1 wt% or more and less than 3 wt% with an internal temperature of the piping of 220 ° C or less Is a method for producing a polycarbonate according to [1] or [2], wherein the internal temperature of the piping is 230 ° C. or lower.
[4] The polycarbonate according to any one of [1] to [3], wherein the obtained polycarbonate has a melt viscosity of 700 Pa · s to 3500 Pa · s at a temperature of 240 ° C. and a shear rate of 91.2 sec ⁻¹ . Manufacturing method.
[5] The production of a polycarbonate according to any one of [1] to [4], wherein the amount of all hydroxy end groups in the molten polycarbonate resin at the outlet of the final reactor is 5 mol / ton or more and 60 mol / ton or less. Method.
[6] When the amount of the monohydroxy compound in the molten polycarbonate resin at the final reactor outlet is A [ppm] and the content of the monohydroxy compound in the obtained polycarbonate is B [ppm], the following formula (5 The method for producing a polycarbonate according to any one of [1] to [5].
AB ≧ 100 (5)
[7] The amount of the double bond terminal structure in the polycarbonate at the outlet of the final reactor is P (mol / ton), and the amount of the double bond terminal structure in the finally obtained polycarbonate is Q (mol / ton). In this case, the polycarbonate production method according to any one of [1] to [6], which satisfies the following formula (6):
Q−P ≦ 10 (6)
[8] The polycarbonate according to any one of [1] to [7], 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. Manufacturing method.
[9] The method for producing a polycarbonate according to any one of [1] to [8], wherein the specific dihydroxy compound having the site represented by the formula (1) is a compound having a cyclic ether structure.
[10] The method for producing a polycarbonate according to [9], wherein the specific dihydroxy compound having a site represented by the formula (1) is a compound represented by the following structural formula (12).

[11] The method for producing a polycarbonate 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 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. Production method.
[13] A step of discharging a polycarbonate obtained by polycondensation or a resin obtained by filtering it through a filter in the form of a strand from a die head, cooling, and then pelletizing using a cutter. [12] The method for producing a polycarbonate according to any one of [12].
[14] Polycarbonate pellets produced by the method according to [13].
[15] When formed into a film having a thickness of 35 μm ± 5 μm, the maximum length 2 contained in the film
The polycarbonate pellet according to [14], wherein foreign matter of 5 μm or more is 1000 pieces / m ² or less.

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

（但し、上記式（１）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
を除く。）すなわち、特定ジヒドロキシ化合物には−ＣＨ₂−ＯＨ以外に式（１）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（１）で表される部位を有する化合物は含まれる。

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 of the present invention, a dihydroxy compound containing a specific dihydroxy compound having a site represented by the following formula (1) in a part of the structure, a carbonic acid diester, and a polymerization catalyst are continuously supplied to a reactor. A method for producing polycarbonate by polycondensation, wherein a plurality of the reactors are connected in series, and the first reactor out of the reactors connected to the plurality of reactors and the step of removing the polycarbonate The temperature defined by the reaction time of the reaction solution or molten polycarbonate in each pipe between them and T _i in each pipe is a method for producing polycarbonate that satisfies the following formula (2).

(However, the site represented by the above formula (1) unless a portion constituting a part of -CH ₂ -OH.) That is, the formula in addition to -CH ₂ -OH in particular dihydroxy compound (1 It does not include compounds having no moiety represented by) but, -CH ₂ -O-CH ₂ other than -CH ₂ -OH -
A compound having a moiety represented by the formula (1) such as is included.

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

  In the method of the present invention, the dihydroxy compound containing the specific dihydroxy compound and the carbonic acid diester are reacted in the presence of a polymerization catalyst in a multistage process of at least two stages using at least two reactors (melt polycondensation). ) To produce polycarbonate. 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. After the polycondensation process, using an extruder equipped with a vacuum vent, etc., the process of devolatilizing and removing unreacted raw materials and reaction by-products in the polycarbonate, heat stabilizers, mold release agents, colorants, etc. You may add suitably the process of removing the foreign material in resin with a filter, the process of forming the obtained polycarbonate in the pellet of a predetermined particle size, etc. in the process to add.

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 liquid or molten polycarbonate 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. This pipe has only an inlet through which the reaction solution or molten polycarbonate 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 reactor, 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 in the pipe used in the above formula (2) is the highest temperature in the pipe. Unless a heating device or cooling device is added in the pipe, the temperature of the reaction liquid or molten polycarbonate at the inlet of the pipe i is compared with the temperature of the reaction liquid or molten polycarbonate at the outlet, and the higher temperature is the pipe temperature. T _i may be used. 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 flowing in 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（４）はポリカーボネート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（４）は、一般のアレニウスの式（４'）

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。さらに、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ｘ_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の熱
履歴を評価する。発明者らは、ポリカーボネート主鎖の熱分解反応によって生じる異種末端構造の生成量と、得られるポリカーボネートの色調が相関することを見出し、ポリカーボネートの色調を熱履歴パラメータｘ_iにより評価するに至った。本発明の重縮合工程に
おける熱分解反応は、ポリカーボネート主鎖の脱炭酸反応のみならず、異種末端構造の生成を伴う複雑な反応の集合体であるが、上記の通り、前記式（４'）における熱分解反応
の生成エネルギーＥは、前記異種末端構造の生成反応における活性化エネルギーとして経験的に求まる。 In the above equation (2), the thermal history parameter x _i in the piping element i is defined as the following equation (4).

T _i : Temperature of the reaction liquid or molten polycarbonate at the inlet of the pipe i and the temperature of the reaction liquid or molten polycarbonate at the outlet, whichever is higher [K] θ _i : Residence time [min] in the pipe i (4) ) Was derived from the Arrhenius equation defining the rate of thermal decomposition of the polycarbonate main chain. That is, the equation (4) is the general Arrhenius equation (4 ′).

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]. Further, assuming that E / R is 12000 [K], the temperature [K] of the reaction liquid or molten polycarbonate at the inlet of the pipe i and the temperature of the reaction liquid or molten polycarbonate at the outlet, whichever is higher, and the pipe i The thermal history of the polycarbonate in the piping element i is evaluated by calculating x _i from the residence time [min]. Inventors have found the production of heterologous terminal structure caused by the thermal decomposition reaction of the polycarbonate backbone, that the color tone of the obtained polycarbonate are correlated, the color tone of the polycarbonate has led to the evaluation by the thermal history parameters x _i. The thermal decomposition reaction in the polycondensation step of the present invention is not only a decarboxylation reaction of the polycarbonate main chain, but also an assembly of complicated reactions involving the generation of heterogeneous terminal structures. As described above, the above-mentioned formula (4 ′) The generation energy E of the thermal decomposition reaction in is determined empirically as the activation energy in the generation reaction of the heterogeneous terminal structure.

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 (2), a polycarbonate satisfying a plurality of quality problems such as improvement of the hue of the obtained polycarbonate and reduction of residual low molecular compounds and foreign substances in the polycarbonate can be obtained. Can do.
When the range of the above formula (2) is exceeded, an excessive heat history is applied to the polycarbonate, the hue of the polycarbonate is deteriorated, and the residual low molecular components generated by thermal decomposition are increased. On the other hand, in order to connect apparatuses, such as a reactor, the piping space more than a certain fixed level is required, Therefore Realization of the area | region which falls below the range of said Formula (2) is difficult.
Furthermore, in the present invention, the molten polycarbonate coming out of the final reactor is in the most viscous state during the production process, and therefore, a large pressure loss occurs when it is transported through the piping. It is preferable to keep the piping at a temperature higher than the temperature. Therefore, the residence time of the piping after the final reactor is the largest factor that degrades the quality of polycarbonate.
Therefore, the residence time until the polycarbonate is taken out from the final reactor at room temperature is preferably within 30 minutes, more preferably 25 minutes or less, and particularly preferably 20 minutes or less. Even when an extruder or a filter is installed after the final reactor, it is important to devise the installation of the apparatus so that the residence time can be kept below the above-mentioned residence time.
In addition, in the piping, decomposition products and colored products generated by thermal degradation may be retained in the reaction solution and the molten polycarbonate. In particular, when a large amount of a monohydroxy compound produced from a carbonic acid diester is contained, the reaction liquid and the molten polycarbonate are likely to be colored due to retention in the piping.
In the present invention, when transferring a reaction liquid containing 6 wt% or more of a monohydroxy compound and molten polycarbonate, the internal temperature of the piping is 210 ° C. or less, and the reaction liquid and molten polycarbonate containing 3 wt% or more and less than 6 wt% are used. The internal temperature of the pipe when transferring is preferably 220 ° C. or less, and the internal temperature of the pipe when transferring the reaction liquid and molten polycarbonate contained in the range of 1 wt% or more and less than 3 wt% is preferably 230 ° C. or less.

<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. 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 one or more vertical stirring reactors can be used for the first stage reaction reactor, and one horizontal stirring reactor can be used for the second stage reaction 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.
In the polycarbonate produced in the present invention, the viscosity of the reaction solution increases with the progress of the reaction, as in the case of ordinary polycarbonates. In order to more effectively remove the hydroxy compound (which becomes phenol when DPC is used) out of the system, and to ensure the fluidity of the reaction solution, the reaction temperature is increased stepwisely, It is necessary to set a higher vacuum.

  The upper limit temperature of the heating medium for heating each of the reactors is usually 270 ° C., preferably 250 ° C., particularly 240 ° 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, since the unreacted dihydroxy compound tends to generate a colored product by thermal decomposition, the temperature of the heating medium in the reactor before the final reactor is preferably less than 240 ° C. 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 specific dihydroxy compound having a site represented by the above formula (1) such as isosorbide (ISB) and a carbonic diester such as diphenyl carbonate (DPC) are melted. The raw material mixture melt is prepared (raw material preparation step), and these compounds are subjected to polycondensation reaction in multiple stages using a plurality of reactors in the molten state in the presence of a polymerization catalyst (polycondensation step). Is done by. In this reaction, since a monohydroxy compound is by-produced, the monohydroxy compound is removed from the reaction system, so that the reaction proceeds and polycarbonate is produced. 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>
The dihydroxy compound containing the specific dihydroxy compound having the site represented by the above formula (1) and the carbonic acid diester used as a raw material of the polycarbonate is a batch type, a semi-batch type or an atmosphere of an inert gas such as nitrogen or argon. Using a continuous stirring tank type apparatus, it is prepared as a raw material mixed melt, or these are dropped independently into a reaction tank. For example, when using ISB as the specific dihydroxy compound and a dihydroxy compound of an alicyclic hydrocarbon as described below and using DPC as a carbonic acid diester, the temperature of the melt mixing is preferably 80 ° C. to 180 ° C., Preferably, it is selected from the range of 90 ° C to 120 ° C. 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 means the value of χ when the βχ value represented by the following formula (11) 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) (11)
(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, and if it is too high, there is a problem such as thermal decomposition. 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 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 reactor while melting, 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 or more and 40 kPa or less, more preferably 5 kPa or more and 30 kPa or less. 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 preceding polycondensation step is supplied to a horizontal stirring reactor, and a polycondensation reaction is performed at an internal temperature of the reactor of 200 ° C. to 260 ° C. to obtain a polycarbonate. 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. In particular, in the final reactor, the pressure is 1 kPa to 10 Pa, 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 this 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 reactor are provided to increase the average molecular weight (reduced viscosity) of the polycarbonate.

  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 reactor in the former reaction step, and it is preferable to use a horizontal stirring reactor in the latter reaction step.

  In the reactor used in the present invention, from the viewpoint of the color tone of the polycarbonate, regardless of whether it is the former stage or the latter stage, from the viewpoint of the color tone of the polycarbonate, the parts that contact the raw material monomer or the polymerization liquid of the components constituting the reaction apparatus, piping, etc. The surface material of the “liquid 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) with a nickel content of 10% by weight or more. It is preferable that it is comprised from 1 type, or 2 or more types. 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 reactor 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. Such a stirring blade is provided in at least two stages per rotation shaft, and the reaction solution is scraped up or spread out by the stirring blade to update the surface of the reaction solution. 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 using the substituted diphenyl carbonate such as diphenyl carbonate and ditolyl carbonate as the carbonic acid diester and producing a polycarbonate by the method of the present invention, phenol or substituted phenol as a monohydroxy compound is produced as a by-product in the polycarbonate. It is inevitable that it remains. However, these monohydroxy compounds such as phenol and substituted phenol may cause odor during molding. The polycarbonate 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 reactor as much as possible to distill it off. However, a polycarbonate using a dihydroxy compound having a structural moiety of the formula (1) represented by ISB as a monomer has a larger reaction equilibrium constant than a conventional aromatic polycarbonate using bisphenol A as a monomer. Therefore, the molecular weight increase rate in the latter stage 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 of using diphenyl carbonate as the dihydroxy compound having the structural moiety of the formula (1) and the carbonic acid diester of the present invention, usually, the amount of the hydroxy end and the amount of the phenyl carbonate end represented by the following structural formula (11) The reaction rate becomes maximum when the amount is equal to each other, but the amount of hydroxy ends is intentionally reduced and the amount of phenyl carbonate ends is increased, thereby slowing the rate of viscosity increase and lowering the pressure in the final reactor. It becomes possible. Furthermore, the smaller the hydroxy end, the more the heat stability of the resulting polycarbonate is improved. For example, the coloration when the resin is melted and retained is reduced.

  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 or more and 1.030 or less. The molar ratio of the charged diester carbonate to the total dihydroxy compound is more preferably 0.995 or more and 1.25 or less. 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 end balance in this way, it is possible to control the rate of viscosity increase in the final reactor, and the pressure in the final reactor can be reduced. The pressure in the final 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 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. The terminal preferably contains 5 mol / ton or more, and more preferably contains 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 according to the present invention is preferably 700 ppm or less, more preferably 500 ppm or less, particularly preferably 200 ppm or less at the outlet of the final reactor. . 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 obtained by polycondensation according to the present invention may be subjected to the polycondensation reaction described above and then filtered through a filter in a molten state without solidifying. 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 required for filtration, the final reactor is extracted in a molten state using a gear pump, a screw, etc., and filtered through a filter, and the final reactor is melted into a single or twin screw extruder. After supplying the resin, melt extrusion, filtering with a filter, cooling and solidifying in the form of a strand, pelletizing with a rotary cutter or the like, or uniaxial or biaxial extrusion in the molten state from the final reactor After the resin is supplied to the machine and melt-extruded, it is once cooled and solidified in the form of strands, pelletized, the pellets are again introduced into the extruder, filtered through a filter, cooled and solidified in the form of strands, and pelletized. The process is carried out by extracting from the final reactor in a molten state, cooling and solidifying in the form of strands without passing through an extruder, once pelletized, and then uniaxially. Supplies pellets twin-screw extruder, was melt-extruded, filtrated with 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 degradation such as deterioration of hue and molecular weight, resin is supplied from the final reactor to a uniaxial or biaxial extruder in a molten state, and melt extrusion is performed. Then, a method of directly filtering with a filter, cooling and solidifying in the form of a strand, 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.

Further, in the polycarbonate obtained by polycondensation as described above, it is usually produced as a by-product in the transesterification reaction, which is a raw material monomer that may adversely affect the product due to hue, heat stability, and further bleed out. Low molecular weight compounds such as monohydroxy compounds and polycarbonate oligomers remain, but these are removed by devolatilization 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. 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, heat stabilizer, neutralizer, ultraviolet absorber, mold release agent, colorant, antistatic agent, lubricant, lubricant, plasticizer, compatibilizer, which are generally known, Flame retardants can be added and 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 taken 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. The types of weaving include plain weave, twill,
Nonwoven fabric types can also be used in addition to those in which the foreign matter collecting portions are regularly woven, such as plain woven fabric and twill woven fabric. 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 from staying in the filter storage container and prevent deterioration of the polycarbonate, it is preferable that the polycarbonate 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.

According to the method of the present invention, a resin having less coloring and less foreign matter can be obtained while being a polycarbonate having the structure of the above formula (1). 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 matters 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 reactor as described above, the amount of the monohydroxy compound in the molten polycarbonate at the outlet of the final reactor is A [ppm], and finally obtained polycarbonate When the content of the monohydroxy compound is B [ppm], the following formula (5) is preferably satisfied.
AB ≧ 100 (5)
Moreover, the polycarbonate which uses the dihydroxy compound and aliphatic dihydroxy compound which have a structure part of the said Formula (1) for a monomer produces | generates a double bond terminal by thermal decomposition. The amount of this terminal group serves as an index indicating the thermal history of the molten polycarbonate, and the amount of the double bond terminal increases as the reaction proceeds at a higher temperature for a longer time. The amount of double bond end groups in the molten polycarbonate at the outlet of the final reactor is P [mol / ton], and the amount of double bond end groups in the finally obtained polycarbonate is Q [mol / ton]. In such a case, it is preferable to satisfy the following formula (6).
Q−P ≦ 10 (6)

As a specific example of the double bond end, for example, an end group of the following structural formula (7) or (7 ′) is generated from ISB. Further, 1,4-cyclohexanedimethanol (CHDM) produces the end group of the following structural formula (8) or (8 ′). When expressed by the general structural formula, a double bond terminal represented by the following structural formula (10) is generated from the dihydroxy compound having a hydroxy group represented by the following structural formula (9). The amount of the double bond terminal structure when ISB and CHDM are used is the sum of the terminal structures represented by the following structural formulas (7), (7 ′), (8), and (8 ′) contained in the resin. Represents an amount. The amount of double bond ends is determined by ¹ H NMR measurement of polycarbonate.

（なお、Ｒ¹，Ｒ²，Ｒ³はそれぞれ水素原子又は置換基を有していても良いアルキル基で
ある。）

(R ¹ , R ² and R ³ are each a hydrogen atom or an alkyl group which may have a substituent.)

<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 undergoes 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. Manufactured. 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, devolatilizing and removing unreacted raw materials and reaction by-products in the molten polycarbonate, adding a heat stabilizer, mold release agent, colorant, etc., forming the polycarbonate into pellets of a predetermined particle size Through the process, polycarbonate pellets are formed.

In the following, isosorbide (ISB) and 1,4-cyclohexanedimethanol (CHDM) were used as the starting dihydroxy compound, diphenyl carbonate (DPC) was used as the starting carbonic acid diester, and calcium acetate was used as the catalyst. An example will be described. ISB corresponds to the specific dihydroxy compound.

  First, in the raw material preparation step, a DPC melt prepared at a predetermined temperature in a nitrogen gas atmosphere is continuously supplied from the raw material supply port 1a to the raw material mixing tank 2a. Also, the ISB melt and the CHDM melt measured in a nitrogen gas atmosphere are continuously supplied to the raw material mixing tank 2a from the raw material supply ports 1b and 1c, 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 reactor 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 1d 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 reactor 6a, a second vertical stirring reactor 6b, a third vertical stirring reactor 6c, and a fourth horizontal stirring reactor 6d are provided in series. It is done. In each reactor, the liquid level is kept constant and a polycondensation reaction is performed, and the polymerization reaction liquid discharged from the bottom of the first vertical stirring reactor 6a passes to the second vertical stirring reactor 6b. The third vertical stirring reactor 6c is successively 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 reactor in the present invention, and the third vertical stirring reactor 6c corresponds to the reactor immediately before the final reactor.

  The first vertical stirring reactor 6a, the second vertical stirring reactor 6b, and the third vertical stirring reactor 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 reactor 6a and the second vertical stirring reactor 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. As for the first vertical stirring reactor 6a and the second vertical stirring reactor 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, cold traps (not shown) are provided downstream of the condensers 12c and 12d attached to the third vertical reactor 6c and the fourth horizontal reactor 6d, respectively, so that by-products are continuously present. Solidified and recovered.

The reaction liquid raised to a predetermined molecular weight is extracted as molten polycarbonate 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. 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 (first vertical stirring reactor 6a, second vertical stirring reactor 6b, third vertical stirring reactor 6c, The four horizontal stirring reactors 6d) are set in advance to a predetermined internal temperature and pressure, respectively. Here, the internal temperature, the heat medium temperature, and the pressure of each reactor are not particularly limited, but are preferably set as follows.
(First vertical stirring reactor 6a)
Internal temperature: 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 reactor 6b)
Internal temperature: 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 reactor 6c)
Internal temperature: 170 ° C. to 230 ° C., pressure: 10 kPa to 1 kPa, heating medium temperature 180 ° C. to 240 ° C.
(Fourth horizontal stirring reactor 6d)
Internal temperature: 200 ° C. to 260 ° C., pressure: 1 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 internal temperature and pressure of the four reactors described above reach within the range of ± 5% of the respective set values, the raw material mixed melt prepared in the raw material mixing tank 2a is separately added to the first reactor. Continuously fed into the vertical stirring reactor 6a. Simultaneously with the start of the supply of the raw material mixed melt, the catalyst is continuously supplied from the catalyst supply port 1d into the first vertical stirring reactor 6a to start the transesterification reaction.

  In the first vertical stirring reactor 6a in which the transesterification reaction is performed, the liquid level of the polymerization reaction liquid 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 reactor 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 tank bottom of the first vertical stirring reactor 6a, discharged to the second vertical stirring reactor 6b, and subsequently discharged from the tank bottom of the second vertical stirring reactor 6b, Sequentially and continuously supplied to the third vertical stirring reactor 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 carrying out the latter reaction as described later. The phenol and partially unreacted monomer to be removed are removed from the system through the distillation pipe 11d to produce a polycarbonate.

  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 solution surface renewal” means that the reaction solution on the liquid surface is replaced with the reaction solution on the lower surface of 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 13.3 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 is possible to obtain a polycarbonate 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 internal temperature and pressure of 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 solution does not receive an excessive heat history, and foreign matters such as gels or burns generated in the obtained polycarbonate are reduced. Also, the color tone is good.

<Raw materials and catalysts>
Hereinafter, raw materials and catalysts that can be used in the polycarbonate production method of the present invention will be described.
(Dihydroxy compound)
The dihydroxy compound used in the method for producing a polycarbonate of the present invention includes a specific dihydroxy compound having a site represented by the formula (1). Specific examples of the specific dihydroxy compound having a site represented by the formula (1) in a part of the structure include oxyalkylene glycols, dihydroxy compounds having an ether group bonded to an aromatic group in the main chain, and cyclic. Examples thereof include dihydroxy compounds having an ether structure.

  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 9,9-bis (4- (2-hydroxyethoxy) phenyl) fluorene and 9,9-bis (4- (2-hydroxy). Propoxy) 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-tert-butylphenyl) fluorene, 9,9-bis (4- (2-hydroxyethoxy) 3-cyclohexylphenyl) fluorene, 9,9-bis (4- (2-hydroxyethoxy) -3-phenylphenyl) fluorene, 9,9-bis (4- (2-hydroxyethoxy) -3,5-dimethylphenyl ) Fluorene, 9,9-bis (4- (2-hydroxyethoxy) -3-tert-butyl-6-methylphenyl) fluorene, 9,9-bis (4- (3-hydroxy-2,2-dimethylpropoxy) ) Phenyl) fluorene, 2,2-bis (4- (2-hydroxyethoxy) phenyl) propane, 2,2-bis (4- (2-hydroxypropoxy) phenyl) propane, 1,3-bis (2-hydroxy) Ethoxy) 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 (12), a spiro glycol represented by the following formula (13) and the following formula (14). 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.

  However, examples of the dihydroxy compound represented by the above formula (12) include isosorbide (ISB), isomannide, and isoidet which are related to stereoisomers, and these may be used alone or in combination. A combination of the above may also be used.

  Among these specific dihydroxy compounds, the dihydroxy compounds represented by the formulas (12), (13), and (14) are selected from the viewpoint of easy availability, handling, reactivity during polymerization, and hue of the obtained polycarbonate. A representative dihydroxy compound having a cyclic ether structure is preferable, and an anhydrous sugar alcohol which is a dihydroxy compound having two sugar-derived cyclic ether structures such as the dihydroxy compound represented by the above formula (12) or the following formula (13) More preferred is a dihydroxy compound having two cyclic ether structures such as spiroglycol represented by formula (12), and is an anhydrous dihydroxy compound having two sugar-derived cyclic ether structures such as the dihydroxy compound represented by the above formula (12). Sugar alcohol is particularly preferred.

  Among these specific dihydroxy compounds, the use of a specific dihydroxy compound having no aromatic ring structure is preferable from the viewpoint of light resistance of the polycarbonate, and among them, various starches that are abundant as plant-derived resources and are easily available. Anhydrosugar alcohols such as dihydroxy compounds represented by the above formula (12) obtained by dehydrating condensation of sorbitol produced are easy to obtain and manufacture, light resistance, optical properties, moldability, heat resistance, carbon Most preferable in terms of neutrality.

  These specific dihydroxy compounds may be used alone or in combination of two or more depending on the required performance of the obtained polycarbonate.

  The polycarbonate produced by the method of the present invention may contain a structural unit derived from a dihydroxy compound other than the specific dihydroxy compound (hereinafter sometimes referred to as “other dihydroxy compound”). Examples of the dihydroxy compound include a linear aliphatic hydrocarbon dihydroxy compound, a linear branched aliphatic hydrocarbon dihydroxy compound, an alicyclic hydrocarbon dihydroxy compound, and aromatic bisphenols.

  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 linear 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 Bis (4-hydroxyphenyl) disulfide, 4,4′-dihydroxydiphenyl ether, 4,4′-dihydroxy-3,3′-dichlorodiphenyl ether, 9,9-bis (4- (2-hydroxyethoxy-2) -Methyl) phenyl) fluorene, 9,9-bis (4-hydroxyphenyl) fluorene, 9,9-bis (4-hydroxy-2-methylphenyl) fluorene and the like.

  These other dihydroxy compounds may be used alone or in combination with the specific dihydroxy compound depending on the required performance of the obtained polycarbonate, or may be used in combination with the specific dihydroxy compound after combining two or more. . Among these, from the viewpoint of the light resistance of polycarbonate, a dihydroxy compound having no aromatic ring structure in the molecular structure, that is, a dihydroxy compound of an aliphatic hydrocarbon or a dihydroxy compound of an alicyclic hydrocarbon is preferable. Also good.

  Among the above, the aliphatic hydrocarbon dihydroxy compound suitable for light resistance is particularly 1,3-propanediol, 1,4-butanediol, 1,5-heptanediol, 1,6-hexanediol. A straight-chain aliphatic hydrocarbon dihydroxy compound having 3 to 6 carbon atoms and having hydroxyl groups at both ends is preferred, and the alicyclic hydrocarbon dihydroxy compound is particularly 1,2-cyclohexanedimethanol, 1,3 -Cyclohexanedimethanol, 1,4-cyclohexanedimethanol, tricyclodecane dimethanol are preferred, and more preferred are 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, etc. Dihydroxy compounds having the cyclohexane structure of Shiino is 1,4-cyclohexanedimethanol.

  By using these other dihydroxy compounds in combination with the specific dihydroxy compound, it is possible to obtain effects such as improvement in flexibility, heat resistance, and moldability of polycarbonate. However, if the content ratio of the structural units derived from the other dihydroxy compounds is too large, the mechanical properties and heat resistance may be decreased. Therefore, the number of moles of structural units derived from all the dihydroxy compounds. The ratio of the structural unit derived from the other dihydroxy compound is preferably 80 mol% or less, more preferably 70 mol% or less, and particularly preferably 60 mol% or less. On the other hand, it is preferably at least 10 mol%, more preferably at least 15 mol%, particularly preferably at least 20 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. . In particular, the specific dihydroxy compound used in the present invention under acidic conditions is likely to be altered, and therefore it is preferable to include a basic stabilizer. 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, trimethylethylammonium hydroxide, trimethyl Benzylammonium hydroxide, trimethylphenylammonium hydroxide, triethylmethylammonium hydroxide, triethylbenzylammonium Bases such as hydroxide, triethylphenylammonium hydroxide, tributylbenzylammonium hydroxide, tributylphenylammonium hydroxide, tetraphenylammonium hydroxide, benzyltriphenylammonium hydroxide, methyltriphenylammonium hydroxide, butyltriphenylammonium hydroxide Ammonium compounds, diethylamine, dibutylamine, triethylamine, morpholine, N-methylmorpholine, pyrrolidine, piperidine, 3-amino-1-propanol, ethylenediamine, N-methyldiethanolamine, diethylethanolamine, diethanolamine, 4-aminopyridine, 2- Aminopyridine, N, N-dimethyl-4-aminopyridine, 4-die Amine compounds such as tilaminopyridine, 2-hydroxypyridine, 2-methoxypyridine, 4-methoxypyridine, 2-dimethylaminoimidazole, 2-methoxyimidazole, imidazole, 2-mercaptoimidazole, 2-methylimidazole, aminoquinoline, Examples thereof include hindered amine compounds such as di- (tert-butyl) amine and 2,2,6,6-tetramethylpiperidine.

  The content of these basic stabilizers in all the dihydroxy compounds used in the present invention is not particularly limited, but the specific dihydroxy compounds used in the present invention are unstable in an acidic state. It is preferable to add a stabilizer so that the pH of the aqueous solution containing the specific dihydroxy compound is 7 or more. If the amount is too small, there is a possibility that the effect of preventing the alteration of the specific dihydroxy compound used in the present invention may not be obtained. If the amount is too large, the specific dihydroxy compound used in the present invention may be modified. It is 0.0001 weight%-1 weight% with respect to each dihydroxy compound, Preferably it is 0.001 weight%-0.1 weight%.

  When these basic stabilizers are included in the dihydroxy compound used in the present invention and used as a raw material for producing polycarbonate, the basic stabilizer itself becomes a polymerization catalyst, which not only makes it difficult to control the polymerization rate and quality, but also the resin hue. Will worsen. Therefore, for specific dihydroxy compounds and those having a basic stabilizer among the other dihydroxy compounds, the basic stabilizer can be removed by ion exchange resin or distillation before being used as a raw material for producing polycarbonate. preferable.

  In addition, since the specific dihydroxy compound used in the present invention is gradually oxidized by oxygen, in order to prevent decomposition due to oxygen during storage or handling during production, water should not be mixed and deoxygenated. It is important to use an agent or to put it in a nitrogen atmosphere. When isosorbide is oxidized, decomposition products such as formic acid are generated. For example, when polycarbonate is produced using isosorbide containing these decomposition products, it not only causes coloration of the resulting polycarbonate and significantly deteriorates physical properties, but also affects the polymerization reaction, thereby obtaining a high molecular weight polymer. It is not preferable because it may not be possible.

  In order to obtain the specific dihydroxy compound which does not contain the decomposition product due to the oxidation, and to remove the above 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. With such distillation purification, when a dihydroxy compound containing the specific dihydroxy compound is used as a polycarbonate production raw material, it is possible to produce a polycarbonate excellent in hue and thermal stability without impairing polymerization reactivity.

(Carbonated diester)
In the present invention, the polycarbonate can be obtained by polycondensation by a transesterification reaction using a dihydroxy compound containing the above-mentioned specific dihydroxy compound and a carbonic acid diester as raw materials.
As a carbonic acid diester used, what is normally represented by following formula (15) is mentioned. 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 (15) 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, and are purified by distillation as necessary. It is preferable to use one.

(Transesterification reaction catalyst)
In the production method of the present invention, the polycarbonate is produced by transesterifying the dihydroxy compound containing the specific dihydroxy compound and the carbonic acid diester represented by the formula (15) 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 carried out in the presence of the transesterification reaction catalyst. The transesterification reaction catalyst that can be used in the production of the polycarbonate of the present invention (hereinafter sometimes simply referred to as catalyst or polymerization catalyst). Can greatly affect the reaction rate and the color tone of the polycarbonate 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, but is not limited to Group 1 or Group 2 in the long-period periodic table. (Hereinafter, simply referred to as “Group 1” and “Group 2”) include basic compounds such as metal compounds, 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 and the like. Among them, from the viewpoint of polymerization activity and hue of the obtained polycarbonate, 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. From the viewpoint of the hue of the polycarbonate obtained, a magnesium compound and / or a calcium compound is more preferable, and a calcium compound is most 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 particularly preferred to use only Group 1 metal compounds and / or Group 2 metal compounds.

  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. If the amount of the catalyst is too small, the polymerization rate becomes slow, so that the polymerization temperature must be increased by that much in order to obtain a polycarbonate having a desired molecular weight. Therefore, there is a high possibility that the hue of the obtained polycarbonate 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, so that the desired molecular weight may not be reached. There is. 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 resulting polycarbonate and coloring of the resin during molding.

  However, sodium, potassium, and cesium among Group 1 metals may adversely affect the hue if they are contained in a large amount in the polycarbonate. 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 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 obtained by polycondensation in this way can be expressed in terms of reduced viscosity, is preferably 0.20 dL / g or more, and preferably 0.30 dL / g or more. It is good that it is 20 dL / g or less, preferably 1.00 dL / g or less, more preferably 0.80 dL / g or less. If the reduced viscosity of the polycarbonate 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 by using a Ubbelohde viscometer at a temperature of 20.0 ° C. ± 0.1 ° C., precisely prepared at a polycarbonate concentration of 0.6 g / dL using methylene chloride as a solvent. is there.
Similarly, the melt viscosity of the polycarbonate obtained by the method of the present invention is preferably 700 Pa · s or more and 3500 Pa · s or less at a temperature of 240 ° C. and a shear rate of 91.2 sec ⁻¹ . Furthermore, 800 Pa · s or more and 3200 Pa · s or less are preferable, and 900 Pa · s or more and 3000 Pa · s or less are particularly preferable. In the present specification, the melt viscosity is measured using a capillary rheometer (manufactured by Toyo Seiki Co., Ltd.).

  The polycarbonate obtained by the method of the present invention can be formed into a molded product by a generally known method such as an injection molding method, an extrusion molding method, or a compression molding method. The method for molding the polycarbonate is not particularly limited, but an appropriate molding method is selected according to the shape of the molded product. When the molded product is in the form of a film or a sheet, the extrusion molding method is preferable, and the injection molding method provides a degree of freedom of the molded product.

  In addition, the polycarbonate obtained by the method of the present invention may be subjected to a heat stabilizer, a neutralizing agent, an ultraviolet absorber, a release agent, a colorant, an antistatic agent, a lubricant, before performing various moldings, if necessary. Additives such as lubricants, plasticizers, compatibilizers, flame retardants and the like can also be mixed with a tumbler, super mixer, floater, V-type blender, nauter mixer, Banbury mixer, extruder, or the like.

  Further, the polycarbonate obtained by the method of the present invention is, for example, aromatic polycarbonate, aromatic polyester, aliphatic polyester, polyamide, polystyrene, polyolefin, acrylic, amorphous polyolefin, ABS, AS, or other synthetic resin, 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.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited by a following example, unless the summary is exceeded. In addition, the symbol of the compound used in description of a following example is as follows. ISB: Isosorbide (Rocket Fleure, trade name: POLYSORB) CHDM: 1,4-cyclohexanedimethanol (New Nippon Rika Co., Ltd., trade name: SKY CHDM) DPC: Diphenyl carbonate (Mitsubishi Chemical Corporation ) Made)

  The composition analysis and physical property evaluation of the reaction solution and polycarbonate 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: A solution: 0.1% phosphoric acid aqueous solution, B solution: acetonitrile A / B = gradient from 40/60 (vol%) to A / B = 0/100 (vol%) in 10 minutes 1mL / min
Sample injection volume: 10 μL

2) Measurement of total hydroxyl end group amount and double bond end group amount in polycarbonate Weighing 30 mg of polycarbonate and dissolving it in about 0.7 mL of deuterated chloroform, putting it in an NMR tube with an inner diameter of 5 mm, ¹ H NMR The spectrum was measured. The amount of total hydroxy end groups and double bond end groups is determined from the ratio of signal strength based on the hydroxy end groups and double bond end groups derived from each dihydroxy compound constituting the polycarbonate, and the structural units derived from each dihydroxy compound. Quantified. The equipment and conditions used are as follows.・ Equipment: JNM-AL400 (resonance frequency 400 MHz) manufactured by JEOL Ltd. ・ Measurement temperature: normal temperature ・ Relaxation time: 6 seconds ・ Number of integrations: 512 times

Analysis of ¹ H NMR in the case of a copolymer polycarbonate of ISB and CHDM exemplified in the present invention is performed as follows. Calculate the integrated value of the next peak.
(A): 5.6-4.8 ppm: derived from all ISB structural units (proton number: 3, molecular weight: 172.14)
(B): 2.2-0.5 ppm: derived from all CHDM structural units (proton number: 10, molecular weight: 170.21)
(C): 4.4 ppm: derived from hydroxy end group of ISB (proton number: 1, molecular weight: 173.14)
(D): 3.6-3.5 ppm: derived from hydroxy end group of ISB (number of protons: 1, molecular weight: 173.14) and derived from hydroxy end group of CHDM (number of protons: 2, molecular weight: 171.21)
(E): 3.5-3.4 ppm: derived from hydroxy end group of CHDM (proton number: 2, molecular weight: 171.21) and ISB double bond end group (proton number: 1, molecular weight: 155.13)
(F): 2.6 ppm: derived from hydroxy end group of ISB (proton number: 1, molecular weight: 17
3.14)
(G): 6.7-6.5 ppm: derived from ISB double bond end group (proton number: 1, molecular weight: 155.13)
(H) 2.3 ppm: derived from CHDM double bond end group (proton number: 2, molecular weight: 153.20)

Value corresponding to the number of moles of each structure. All ISB structural units: (a) integral value / 3 = (a ′)
All CHDM structural units: (b) integral value / 10 = (b ′)
ISB hydroxy end group: (c) integral value + (f) integral value = (c ′)
-Hydroxy terminal group of CHDM: {(d) integral value- (f) integral value} / 2 + {(e) integral value- (g) integral value} / 2 = (d ')
ISB double bond end group: (g) integrated value = (e ′)
CHDM double bond end group: (h) integral value / 2 = (f ′)

Amount of each end group (unit: mol / ton)
ISB hydroxy end group amount: (c ′) / (g ′) × 1000000
-Hydroxyl end group amount of CHDM: (δ ') / (g') x 1000000
ISB double bond end group amount: (e ′) / (g ′) × 1000000
CHDM double bond terminal group amount: (f ′) / (g ′) × 1000000 However, (g ′) = (a ′) × 172.14 + (b ′) × 170.21.

3) Reduced viscosity A methylene chloride was used as a solvent to prepare a polycarbonate solution having a concentration of 0.6 g / dL. 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 η _sp / C. The higher this value, the higher the molecular weight.

4) Melt viscosity of polycarbonate The polycarbonate 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.

5) Polycarbonate pellet YI value The hue of polycarbonate was evaluated by measuring the YI value (yellow index value) in the reflected light of the pellet 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.

6) 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.

[Example 1]
As shown in FIG. 1 described above, polycarbonate 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 internal temperature and pressure according to the reaction conditions. Next, ISB, CHDM, and DPC are mixed at a constant molar ratio (ISB / CHDM / DPC = 0.700 / 0.300 / 1.005) in a nitrogen gas atmosphere in the raw material preparation step, and 120 ° C. To obtain a raw material mixed melt.

Subsequently, this raw material mixed melt is continuously supplied into the first vertical stirring reactor 6a controlled within the range of ± 5% of the above-mentioned predetermined temperature and pressure through the 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 reactor 6a is 80 minutes. It was. Simultaneously with the start of supply of the raw material mixed melt, a calcium acetate aqueous solution as a catalyst is continuously supplied into the first vertical stirring reactor 6a from the catalyst supply port 1d at a ratio of 1.5 μmol with respect to 1 mol of all dihydroxy components. did.

The polymerization reaction liquid discharged from the bottom of the first vertical stirring reactor 6a is continuously supplied to the second vertical stirring reactor 6b, the third vertical stirring reactor 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 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, the limit was 200 rpm. In this state, the cylinder temperature was lowered to the allowable range of the motor load and set to 180 ° C.

In Example 1, the gear pump 4d on the discharge side of the extruder 15a and the polymer filter 15b were not installed, but 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, the reaction liquid corresponding to the final reactor outlet was sampled from the valve attached after the gear pump 4c, and the polycarbonate pellets were sampled after the strand cutter 16b, and various analyzes were performed by the above-described analysis methods.
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. 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.

[Example 2]
The same procedure as in Example 1 was performed except that no extruder was used. Compared to Example 1, the content of the monohydroxy compound increased. It can be seen that the monohydroxy compound is increasing before the polycarbonate is removed from the outlet of the final reactor. However, since the residence time was short, the quality of the obtained polycarbonate was good.

[Example 3]
The same operation as in Example 1 was conducted except that the internal temperature of the first vertical stirring reactor 6a was 200 ° C. and the internal temperature of the second vertical stirring reactor 6b was 210 ° C. Although the color tone was slightly deteriorated as compared with Example 1, the quality of the obtained polycarbonate was good.

[Example 4]
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. Other than that was carried out in the same manner as in Example 1.
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 set to 225 ° C.
Compared to Example 1, the amount of foreign matter in the polycarbonate 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 was good.

[Example 5]
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 280 rpm, and the temperature of the polymer filter was 230 ° C. Except for the above, the same procedure as in Example 4 was performed.
The color tone of the obtained polycarbonate 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. Adjust the screw speed of the extruder and the temperature setting of the polymer filter in the same way as above, the screw speed is 120 rpm, and the polymer filter temperature is 220 ° C.
It was. Except for the above, the same procedure as in Example 4 was performed.
The color tone of the obtained polycarbonate 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 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 4 was performed except that the screw speed of the extruder was 270 rpm.
The color tone of the obtained polycarbonate 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 polycarbonates using bisphenol A as a monomer.

[Summary]
As shown in the results of Table 2, by setting the heat history in the pipe to a predetermined range, it is possible to improve a plurality of qualities of polycarbonate such as color tone and residual low molecular components. Furthermore, by using an extruder or a filter under the condition of suppressing thermal deterioration, it is possible to reduce foreign matters while maintaining the color tone.

1a Raw material (carbonic acid diester) supply port 1b, 1c Raw material (dihydroxy compound) supply port 1d 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 First vertical reaction Tank 6b 2nd vertical reaction tank 6c 3rd vertical reaction tank 6d 4th horizontal reactor 7a, 7b, 7c Max blend blade 7d 2 axis glasses type stirring blade 8a, 8b Internal heat exchanger 9a, 9b Reflux cooler 10a 10b Reflux pipes 11a, 11b, 11c, 11d Distillation 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 Weighing device 16f Goods bag (paper bag, such as a flexible container)

Claims (15)

A dihydroxy compound containing a specific dihydroxy compound having a site represented by the following formula (1) as part of the structure, a carbonic acid diester, and a polymerization catalyst are continuously supplied to the reactor, and polycondensed to produce a polycarbonate. In the method, a plurality of reactors are connected in series at least, and a reaction in each pipe between the first reactor among the reactors connected to the plurality of reactors and the step of taking out the polycarbonate. polycarbonate production method temperature defined by T _i in residence time and the pipes of the liquid or melt polycarbonate satisfies the following formula (2).

(However, the site represented by the above formula (1) unless a portion constituting a part of -CH ₂ -OH.)

T _i : Temperature of the reaction liquid or molten polycarbonate at the inlet of the pipe i and the temperature of the reaction liquid or molten polycarbonate at the outlet, whichever is higher [K] θ _i : Residence time [min] in the pipe i The method for producing a polycarbonate according to claim 1, wherein the residence time until the polycarbonate is taken out from the outlet of the final reactor at room temperature is within 30 minutes. A pipe for devolatilizing and removing the monohydroxy compound as a reaction byproduct is connected to the reactor. When transferring a reaction solution containing 6 wt% or more of a monohydroxy compound produced from a carbonic acid diester, the internal temperature of the pipe Is 210 ° C. or less, and when transferring a reaction liquid containing 3 wt% or more and less than 6 wt%, the internal temperature of the pipe is 220 ° C. or less, and when transferring a reaction liquid containing 1 wt% or more and less than 3 wt%, The method for producing a polycarbonate according to claim 1 or 2, wherein the internal temperature is 230 ° C or lower. 4. The method for producing a polycarbonate according to claim 1, wherein the obtained polycarbonate has a melt viscosity of 700 Pa · s to 3500 Pa · s at a temperature of 240 ° C. and a shear rate of 91.2 sec ⁻¹ . The method for producing a polycarbonate according to any one of claims 1 to 4, wherein the amount of all hydroxy end groups in the molten polycarbonate resin at the outlet of the final reactor is 5 mol / ton or more and 60 mol / ton or less. When the amount of the monohydroxy compound in the molten polycarbonate resin at the final reactor outlet is A [ppm] and the content of the monohydroxy compound in the obtained polycarbonate is B [ppm], the following formula (5) is satisfied. The manufacturing method of the polycarbonate of any one of Claims 1 thru | or 5.
AB ≧ 100 (5) When the amount of the double bond terminal structure in the polycarbonate at the outlet of the final reactor is P (mol / ton), and the amount of the double bond terminal structure in the finally obtained polycarbonate is Q (mol / ton) The manufacturing method of the polycarbonate of any one of Claims 1 thru | or 6 which satisfy | fills following formula (6).
Q−P ≦ 10 (6) The method for producing a polycarbonate according to any one of claims 1 to 7, 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 according to any one of claims 1 to 8, wherein the specific dihydroxy compound having a site represented by the formula (1) is a compound having a cyclic ether structure. The method for producing a polycarbonate according to claim 9, wherein the specific dihydroxy compound having the site represented by the formula (1) is a compound represented by the following structural formula (12).

The method for producing a polycarbonate according to any one of claims 1 to 10, comprising a step of supplying the polycarbonate resin obtained by the polycondensation to an extruder in a molten state without solidifying. The method for producing a polycarbonate according to any one of claims 1 to 11, comprising a step of supplying the polycarbonate resin obtained by the polycondensation to a filter in a molten state without solidification and filtering. The polycarbonate obtained by polycondensation or a resin obtained by filtering it through a filter is discharged from a die head in the form of a strand, cooled, and then pelletized using a cutter. 2. A method for producing a polycarbonate according to item 1. Polycarbonate pellets produced by the method according to claim 13. 15. The polycarbonate pellet according to claim 14, wherein when formed into a film having a thickness of 35 μm ± 5 μm, the number of foreign matters having a maximum length of 25 μm or more contained in the film is 1000 / m ² or less.

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