JP5857852B2 - Polycarbonate production method, polycarbonate pellet and transparent film - Google Patents

Description

  The present invention relates to a method for efficiently and stably producing a polycarbonate excellent in optical properties, hue and thermal stability and having few foreign matters, and a transparent film obtained therefrom.

  Polycarbonate is generally made of bisphenol as a monomer component, making use of advantages such as transparency, heat resistance or mechanical strength, so-called engineering in the optical field such as electrical / electronic parts, automotive parts, optical recording media or lenses. Widely used as plastic.

  In recent years, copolymer polycarbonates derived from dihydroxy compounds having a fluorene structure in the side chain have been reported. Particularly, copolymer polycarbonates with aliphatic dihydroxy compounds have excellent optical properties such as a low photoelastic coefficient. It is shown (patent documents 1 to 3).

  Patent Document 4 discloses that a retardation film made of a polycarbonate containing a fluorene structure has a low photoelastic coefficient and a reverse wavelength dispersion that decreases as the retardation becomes shorter. It is disclosed that it is useful for optical applications such as.

  When the copolymer polycarbonate using the dihydroxy compound having the fluorene structure is produced, it is produced by a method called a transesterification method or a melting method in which various dihydroxy compounds can be used as raw materials.

  In the above method, a polycarbonate is obtained by transesterifying a dihydroxy compound and a carbonic acid diester such as diphenyl carbonate at a high temperature of 200 ° C. or higher in the presence of a polymerization catalyst, and removing the by-product phenol out of the system to obtain a polycarbonate. It was.

  However, when a copolymerization reaction between a dihydroxy compound having a fluorene structure and the above-mentioned aliphatic dihydroxy compound is performed, the aliphatic dihydroxy compound has lower thermal stability than bisphenols, and the polycondensation reaction is performed at a high temperature. There was a problem that the resin was colored by the thermal decomposition of.

  One way to solve this problem is to increase the reaction efficiency by increasing the surface area of the reaction solution using a horizontal stirring reactor, thereby performing a polymerization reaction with less heat history and improving the color tone of the resulting polymer. Has been proposed (see Patent Document 5).

Japanese Unexamined Patent Publication No. 10-101786 Japanese Unexamined Patent Publication No. 2004-67990 International Publication No. 2006/41190 Japanese Unexamined Patent Publication No. 2008-111047 Japanese Unexamined Patent Publication No. 2009-161745

  According to the study by the present inventors, when a polycarbonate is produced by a transesterification method using a dihydroxy compound having a fluorene structure, in order to provide the resin with sufficient moldability and mechanical strength, in the reaction step, up to a certain molecular weight. On the other hand, it is important to lower the reaction temperature as much as possible in order to reduce the coloration of the resin, and when trying to achieve both, the molten resin is very high at the end of the reaction process. The problem of viscosity became obvious.

  In addition, if the viscosity of the molten resin becomes too high, the molten resin wraps around the stirring shaft in the reactor and does not hang down, making it difficult to extract the molten resin from the reactor at a constant flow rate. The process was interrupted in the middle, and the subject to which the yield of manufacture deteriorated was discovered.

  Furthermore, when the pelletization is stopped in this way, the amount of foreign matter temporarily contained in the resin after the operation even if the pelletization process is isolated in a clean room when performing the operation to restore the pelletization again. The problem of increasing was also found.

  In particular, when used in optical materials, foreign matter can be a fatal defect of the product. Especially when the obtained resin is used for optical film applications, the stage of film formation or the assembly stage of components The product yield will also deteriorate.

  Therefore, the present invention solves the above-mentioned problems in the production of a polycarbonate using a dihydroxy compound having a fluorene structure, stabilizes a polycarbonate having excellent properties such as optical properties and mechanical properties with little coloring. It aims at manufacturing with high quality and high yield, and in particular, even when an aliphatic dihydroxy compound having lower thermal stability than bisphenols is used in combination, the object is to solve the above problems.

That is, the present invention is as follows.
1. A method of polycarbonate in which a dihydroxy compound containing a dihydroxy compound having a fluorene structure, a carbonic acid diester, and a polymerization catalyst are continuously supplied to a reactor and polycondensed to produce a polycarbonate, wherein the reactor is at least in series. A plurality of devices are connected, the internal temperature of the reactor immediately before the final polymerization reactor is 200 ° C. or higher and lower than 225 ° C., and the reaction liquid at the outlet of the reactor immediately before the final polymerization reactor The manufacturing method of polycarbonate characterized by the melt viscosity of 20 Pa · s or more and 1000 Pa · s or less.

2. When the reduced viscosity of the reaction liquid at the outlet of the reactor immediately before the final polymerization reactor is P and the reduced viscosity of the reaction liquid at the outlet of the final polymerization reactor is Q, the following formula (2) is satisfied. 2. A process for producing a polycarbonate according to item 1 above.
1.5 ≦ Q / P ≦ 3.0 (2)

3. 3. The method for producing a polycarbonate according to item 1 or 2, wherein the final polymerization reactor is a horizontal stirring reactor having a plurality of horizontal rotation axes therein, and the reaction condition satisfies the following formula (3): .
500 ≤ ωμ ≤ 20000 (3)
[Ω: stirring blade rotation speed (rpm), μ: melt viscosity (Pa · s) of the reaction liquid at the outlet of the horizontal reactor]

4). 4. The method for producing a polycarbonate according to item 3, wherein reaction conditions of the horizontal stirring reactor satisfy the following formula (4).
2 ≦ V / A ≦ 13 (4)
[V: Horizontal reactor volume (L), A: Reaction liquid throughput (kg / hr)]

5. 5. The method for producing a polycarbonate according to any one of items 1 to 4, wherein the melt viscosity of the reaction solution at the outlet of the final polymerization reactor is 1800 Pa · s or more and 5000 Pa · s or less.

6). 6. The method for producing a polycarbonate according to any one of 1 to 5 above, wherein the temperature of the heating medium in the final polymerization reactor is 220 ° C. or higher and 260 ° C. or lower.

7). 7. The method for producing a polycarbonate according to any one of items 1 to 6 above, wherein a molar ratio of charging the carbonic acid diester to all dihydroxy compounds used in the reaction when charged into the first reactor is 0.990 or more and 1.030 or less. .

8). 8. The method for producing a polycarbonate according to any one of 1 to 7 above, wherein the amount of all hydroxy end groups in the reaction solution at the outlet of the final polymerization reactor is 50 ppm or more and 1000 ppm or less.

9. The amount of the monohydroxy compound in the reaction liquid at the inlet of the final polymerization reactor is 10 ppm or more and 3 wt% or less, and the amount of the monohydroxy compound in the reaction liquid at the outlet of the final polymerization reactor is 1 ppm or more and 1500 ppm or less. 9. The method for producing a polycarbonate according to any one of 1 to 8 above.

10. 10. The method for producing a polycarbonate according to any one of 1 to 9 above, wherein the pressure in the final polymerization reactor is 10 Pa or more and 2 kPa or less.

11. 11. The method for producing a polycarbonate according to any one of items 1 to 10, 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.

12 12. The method for producing a polycarbonate according to any one of items 1 to 11, wherein the dihydroxy compound having a fluorene structure is a compound represented by the following formula (1).

[In General Formula (1), R ^{1 to} R ⁴ are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted carbon group having 6 to 20 carbon atoms. It represents a cycloalkyl group or a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, and the same or different groups are arranged as each of the four substituents on each benzene ring. X is a substituted or unsubstituted alkylene group having 2 to 10 carbon atoms, a substituted or unsubstituted cycloalkylene group having 6 to 20 carbon atoms, or a substituted or unsubstituted carbon atom having 6 to 20 carbon atoms. Represents an arylene group. m and n are each independently an integer of 0 to 5. ]

13. In addition to the dihydroxy compound having a fluorene moiety represented by the formula (1), a dihydroxy compound containing a specific dihydroxy compound having a moiety represented by the following formula (5) in a part of the structure is used for the reaction. The method for producing a polycarbonate according to any one of the above.

[Except where moiety represented by the formula (5) is a portion constituting a part of the dihydroxy compound having when a portion constituting a part of -CH 2 _-OH, and the fluorene structure. ]

14 14. The method for producing a polycarbonate according to any one of items 1 to 13, wherein the specific dihydroxy compound having a site represented by the formula (5) is a compound having a cyclic structure and an ether structure.

15. 15. The method for producing a polycarbonate according to 14 above, wherein the specific dihydroxy compound having a bond structure of the formula (5) is a compound having a heterocyclic group represented by the following structural formula (6).

16. 16. The method for producing a polycarbonate according to any one of the preceding items 1 to 15, comprising a step of supplying the polycarbonate obtained by polycondensation to a filter in a molten state without solidification and filtering.

17. Any one of the preceding items 1 to 16, comprising a step of discharging a polycarbonate obtained by polycondensation or a resin obtained by filtering the polycarbonate through the above-mentioned filter in the form of a strand from a die head, cooling and then pelletizing with a cutter. A method for producing the polycarbonate according to 1.

18. 18. Polycarbonate pellets produced by the production method according to item 17 above.

19. 19. The polycarbonate pellet according to 18 above, wherein the number of foreign matters having a maximum length of 20 μm or more is 1000 / m ² or less, which is included when the film has a thickness of 30 μm ± 5 μm.

20. 18. A transparent film obtained by forming a film of the polycarbonate obtained by the production method according to any one of items 1 to 17 above.

21. 21. A transparent film obtained by stretching the transparent film according to item 20 in at least one direction.

22. 22. The transparent film as described in 20 or 21 above, wherein the ratio of the retardation (Re450) measured at a wavelength of 450 nm and the retardation (Re550) measured at a wavelength of 550 nm satisfies the following formula (7).
0.5 ≦ Re450 / Re550 ≦ 1.0 (7)

  By the method for producing a polycarbonate of the present invention, a polycarbonate excellent in optical properties, hue, heat resistance, thermal stability, mechanical strength and the like can be produced efficiently and stably. In particular, according to the method for producing a polycarbonate of the present invention, it is possible to produce a polycarbonate having a small amount of foreign matter and suitably used for optical applications with a high yield.

FIG. 1 is an overall process diagram showing an example of a method for producing a polycarbonate according to the present invention. FIG. 2 is a perspective view of a biaxial glasses-type stirring blade. FIG. 3 is a schematic plan view showing an example of a horizontal stirring reactor.

  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.

  The polycarbonate production method of the present invention is a method for producing a polycarbonate by continuously supplying a dihydroxy compound containing a dihydroxy compound having a fluorene structure, a carbonic acid diester, and a polymerization catalyst to a reactor and performing polycondensation. A plurality of the reactors are connected in series, and the internal temperature of the reactor immediately before the final polymerization reactor is 200 ° C. or higher and lower than 225 ° C., and The melt viscosity of the reaction liquid at the outlet of the reactor is 20 Pa · s or more and 1000 Pa · s or less. Hereinafter, the production method of the polycarbonate of the present invention may be referred to as “the production method of the present invention”.

<Outline of polycarbonate production process>
In the production 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 weight). Polycarbonate is produced by condensation.

  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 whose main purpose is to mix and dissolve the raw materials in advance, or the piping for transferring the reaction liquid, even if the reaction proceeds slightly, Not included in the reactor.

  In the present specification, the “final polymerization reactor” is a reactor provided on the most downstream side, and the reduced viscosity of the reaction solution at the outlet of the reactor is the reaction preceding the reactor. That which is 1.5 times or more the reduced viscosity of the reaction solution in the vessel. However, as long as the reduced viscosity satisfies the above conditions, an extruder or the like is regarded as a final polymerization reactor.

  The polymerization process is divided into two stages, a pre-stage reaction and a post-stage reaction. The pre-reaction is preferably carried out at a temperature of 130 to 225 ° C., more preferably 150 to 220 ° C., preferably for 0.1 to 10 hours, more preferably 0.5 to 3 hours. To produce oligomers.

  In the latter stage reaction, the pressure in the reaction system is gradually lowered from the previous stage reaction, the reaction temperature is gradually increased, and the monohydroxy compound generated at the same time is removed from the reaction system, and the pressure in the reaction system is preferably reduced to the final reaction. The polycondensation reaction is performed under a temperature range of 2 kPa or less, preferably 200 to 260 ° C., more 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 the reactor for the first stage reaction preferably has one or more vertical stirring reactors, and the reactor for the second stage reaction preferably has one or more horizontal stirring reactors. .

  In the production method of the present invention, the reaction conditions of the horizontal stirring reactor in the final stage can have an important influence not only from the quality of the resin obtained but also from various viewpoints such as the production yield or the amount of foreign matter in the resin. In addition, not only the relationship between the former stage and the latter stage, but also between the former stage reactors and between the latter stage reactors, the temperature increased stepwise and the pressure decreased stepwise as the latter reactor was reached. Setting is preferable.

  The connection between the reactor and the next reactor may be performed by direct piping only, 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 without cooling and solidifying, has no gas phase on the polymer side, and does not cause a dead space.

  The temperature of the heating medium for heating each of the reactors is preferably 260 ° C. or higher, more preferably 255 ° C. or higher, and particularly preferably 250 ° C. or higher. If the temperature of the heating medium is too high, thermal deterioration on the reactor wall surface is promoted, which may lead to problems such as an increase in different structures or decomposition products, or deterioration in color tone.

  In particular, the temperature of the heating medium in the reactor before the final polymerization reactor is preferably less than 230 ° C., since an unreacted dihydroxy compound is likely to generate a colored product by thermal decomposition. The lower limit of the 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, a reactor having a coiled heat transfer tube inside, and the like can be mentioned.

  The reaction method of the production method according to the present invention is preferably a continuous method. As the reactor, a plurality of vertical stirring reactors and then at least one horizontal stirring reactor are used. These reactors are installed in series and processed continuously.

  After the polycondensation step, the obtained polycarbonate is formed into pellets having a predetermined particle size. Further, a step of devolatilizing and removing an unreacted raw material or a reaction byproduct monohydroxy compound in the polycarbonate, a step of adding a thermal stabilizer, a release agent, or the like may be added as appropriate.

  Monohydroxy compounds such as phenol generated in the reactor are collected in a tank and, after effective recovery from the viewpoint of effective resource utilization, recovered and reused as raw materials such as DPC or 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 concerning the manufacturing method of this invention is demonstrated. The production method of the present invention comprises a dihydroxy compound containing a dihydroxy compound (fluorene dihydroxy compound) having a fluorene structure such as 9,9-bis [4- (2-hydroxyethoxy) phenyl] fluorene (BHEPF) as a raw material monomer; , Diphenyl carbonate (DPC) and other carbonic acid diesters are each melted to prepare a raw material mixed melt (raw material preparation step), and these compounds are melted in the presence of a polymerization catalyst in a plurality of reactors. The polycondensation reaction is performed in multiple stages (polycondensation step).

  In the reaction, since a monohydroxy compound is by-produced, the monohydroxy compound is removed from the reaction system, so that the reaction proceeds to produce polycarbonate. 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.

<Raw material preparation process>
The dihydroxy compound including the fluorene-based dihydroxy compound used as a raw material for polycarbonate and the carbonic acid diester use a batch, semi-batch or continuous stirring tank type apparatus in an inert gas atmosphere such as nitrogen or argon. Then, it is prepared as a raw material mixed melt, or these are dropped independently into a reaction vessel.

  For example, when BHEPF is used as the fluorene-based dihydroxy compound and a dihydroxy compound having a cyclic ether structure such as ISB described later is used and DPC is used as the carbonic acid diester, the temperature of the melt mixing is 80 ° C. to 180 ° C. Preferably, it is selected from the range of 90 ° C to 130 ° C.

  Moreover, you may add antioxidant to the said raw material mixing melt. By adding a hindered phenolic antioxidant and / or a phosphorus-based antioxidant that is generally known, by improving the storage stability of the raw material in the raw material preparation step, and suppressing coloring during polymerization, The hue of the resulting resin can be improved.

  The polymerization catalyst to be used is usually preferably prepared in advance as an aqueous solution. 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 can also select other solvents, such as acetone, alcohol, toluene, or phenol.

  Specific examples of the polymerization catalyst will be described later. The property of water used for dissolving the polymerization catalyst is not particularly limited as long as the kind and concentration of impurities contained are constant, but usually distilled water or deionized water is preferably used.

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.

  The reaction is preferably carried out continuously in a multi-tank system of 1 tank or more, more preferably 2-6 tanks, and 40% to 95% of the theoretical amount of monohydroxy compound produced as a by-product is distilled off. preferable. The reaction temperature is preferably 130 ° C. to 225 ° C., more 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 preferably from 0.1 to 10 hours, more preferably from 0.5 to 5 hours, still more preferably from 0.5 to 3 hours.

  If the temperature is too high, thermal decomposition is promoted, the generation of different structures or colored components is increased, 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 be distilled and the reactivity will be lowered. If it is too low, raw materials such as unreacted dihydroxy compound and / or carbonic acid diester will be distilled, so that the molar ratio of the raw materials will be shifted and desired Control of the reaction becomes difficult, for example, the molecular weight is not reached, 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 200 ° C. to 250 ° C. to obtain a polycarbonate. This reaction is preferably carried out continuously in one or more horizontal stirring reactors, more preferably 1 to 3 horizontal stirring reactors.

  The reaction temperature is preferably 210 to 260 ° C, more preferably 220 to 250 ° C. The pressure is preferably 13.3 kPa to 10 Pa, more preferably 1 kPa to 20 Pa. In particular, in the final polymerization reactor, the pressure is preferably 2 kPa to 10 Pa, more preferably 1 kPa to 20 Pa. The average residence time is preferably 0.1 to 10 hours, more preferably 0.5 to 5 hours, and still more preferably 0.5 to 2 hours.

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

  Examples of the reactor include a vertical stirring reactor and a horizontal stirring reactor. Specific examples include a stirred tank reactor, a thin film reactor, a centrifugal thin film evaporation reactor, a surface renewal type biaxial kneading reactor, a biaxial horizontal type stirred reactor, a wet wall reactor, and polymerizing while freely dropping. Examples thereof include a perforated plate reactor, and a perforated plate reactor with a 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 according to the present invention, regardless of the preceding stage and the subsequent stage, from the viewpoint of the color tone of the polycarbonate, a part that contacts the raw material monomer or polymerization liquid of components constituting the reaction apparatus, piping, etc. The surface material is a ratio that occupies at least 90% or more of the total surface area of the wetted part, and is one of stainless steel, glass, nickel, tantalum, chromium and Teflon (registered trademark) having a nickel content of 10% by weight or more. It is preferably composed of seeds or two or more kinds.

  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-described substance and another substance, or a material obtained by plating the 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 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 Industries Co., Ltd.], helical ribbon blades and twisted lattice blades [manufactured by Hitachi, Ltd.].

  Further, the horizontal stirring reactor mentioned above has a plurality of stirring blades extending in a substantially vertical direction with respect to the rotation axis of a plurality of stirring blades provided in the horizontal direction (horizontal direction). The stirring blades provided on the respective horizontal rotating 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 and a paddle type, and HVR, SCR, N-SCR [manufactured by Mitsubishi Heavy Industries, Ltd.], Vivolak [manufactured by Sumitomo Heavy Industries, Ltd.] ], A biaxial type stirring blade such as a spectacle blade and a lattice blade [manufactured by Hitachi, Ltd.]. In addition, for example, stirring blades such as a wheel shape, a saddle shape, a rod shape, and a window frame shape may be mentioned.

  Such a stirring blade is provided in at least two or more stages per rotating shaft, and the reaction solution is scraped up or expanded by the stirring blade to update the surface of the reaction solution. Further, L / D is preferably 1 to 15, more 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.

  In the production method of the present invention, since the reaction conditions in the final polymerization reactor affect not only the quality of polycarbonate but also the production yield, both the quality and the yield are considered in consideration of the above conditions. It is preferable to set the reaction conditions.

  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 preferable to set a higher vacuum.

  In order to prevent quality deterioration such as color tone of the obtained polycarbonate, it is preferable to set a low temperature and a short residence time as much as possible. However, when the reaction temperature is lowered, the melt viscosity becomes high and the fluidity of the reaction liquid is lowered. In particular, in the case of a horizontal stirring reactor, the reaction liquid may be entangled with the stirring shaft and may not sag.

  When the reaction liquid stops flowing quantitatively at the outlet of the reactor, bubbles are trapped in the reaction liquid, and in the pelletizing step, the strand containing the bubbles is cut and the pelletization is stopped. Furthermore, since the operation | work which connects a strand to a cutter generate | occur | produces in order to recover pelletization, there exists a possibility that the foreign material resulting from the fiber of clothes, dust, etc. may mix in a product. For this reason, it is not necessary to simply lower the reaction temperature.

  On the other hand, from the viewpoint of the color tone of the polycarbonate obtained, it is necessary to minimize the residence time in the final polymerization reactor where the reaction temperature is the highest, so the reaction liquid charged into the final polymerization reactor is It is preferable that the temperature be as low as possible and have a high molecular weight (high viscosity).

  For this reason, the internal temperature of the reactor at the outlet of the reactor immediately before the final polymerization reactor is less than 225 ° C, preferably 220 ° C or less, more preferably 215 ° C or less. On the other hand, if the temperature is too low, the reaction does not proceed sufficiently and the viscosity increases too much, so the internal temperature of the reactor immediately before the final polymerization reactor is 200 ° C. or higher, preferably 210 ° C. or higher. .

  The melt viscosity of the reaction solution at the outlet of the reactor immediately before the final polymerization reactor is 20 Pa · s or more, preferably 50 Pa · s or more, more preferably 100 Pa · s or more. On the other hand, it is 1000 Pa · s or less, preferably 800 Pa · s or less.

  In order to remove low-molecular components such as monohydroxy compounds remaining in the polymer, it is preferable that the degree of vacuum of the final polymerization reactor is as high as possible. However, if the viscosity of the reaction solution is too low, the reaction solution foams violently and is ideal. The plug flow property cannot be obtained, and the molecular weight cannot be controlled. On the other hand, if the viscosity is too high, the fluidity in the final polymerization reactor is lowered, the residence time becomes excessive, and the quality such as the color tone of the obtained polycarbonate is deteriorated.

The melt viscosity of the reaction liquid at the outlet of the reactor immediately before the final polymerization reactor can be controlled to a desired viscosity by appropriately adjusting the temperature or pressure of the previous reaction, the amount of catalyst, or the like. In the present specification, the melt viscosity refers to the melt viscosity at a shear rate of 91.2 s ⁻¹ measured at the same temperature as the reaction solution using a capillary rheometer [manufactured by Toyo Seiki Co., Ltd.].

  The temperature of the heating medium in the final polymerization reactor is preferably 260 ° C. or lower, more preferably 255 ° C. or lower, and further preferably 250 ° C. or lower. On the other hand, if the viscosity is too low, the viscosity will increase too much, so the temperature of the heating medium is preferably 220 ° C. or higher, more preferably 230 ° C. or higher.

  Further, in the final polymerization reactor, in order to efficiently remove low molecular components from the reaction solution, monohydroxy such as phenol contained in the reaction solution at the outlet of the reactor immediately before the final polymerization reactor. The amount of the compound is preferably 3 wt% or less, more preferably 2 wt% or less, and particularly preferably 1.5 wt% or less.

  To reduce the content of monohydroxy compounds, there are methods such as reducing the pressure and increasing the residence time in the reactor upstream of the final polymerization reactor, but the viscosity of the reaction solution does not increase excessively. Thus, it is preferable to adjust the reaction conditions.

  In addition, although the amount of the monohydroxy compound contained is preferably as small as possible, it is impossible in practice, but is ideally 0 wt%. However, it is impossible in practice, and it is usually preferably 500 ppm or more.

  On the other hand, in the final polymerization reactor, it is necessary to improve the molecular weight to such an extent that the obtained resin has sufficient mechanical properties, so the melt viscosity of the reaction liquid at the outlet of the final polymerization reactor is 1800 Pa · s or more. More preferably, it is 2000 Pa · s or more, and particularly preferably 2200 Pa · s or more.

  On the other hand, if the melt viscosity is increased too much, the fluidity of the reaction solution is impaired, and the load on the stirrer motor increases, so the melt viscosity is preferably 5000 Pa · s or less, and preferably 4000 Pa · s or less. It is more preferable.

  The melt viscosity of the reaction liquid at the outlet of the final polymerization reactor should be controlled by adjusting the reaction conditions such as the temperature, pressure or residence time of the final polymerization reactor or the amount of catalyst, or adjusting the end group balance. Can do. The end group balance is adjusted by controlling the charged molar ratio of the carbonic diester and the dihydroxy compound, or the amount of unreacted monomer distilled in the previous reaction.

  In the above reaction conditions, when the degree of increase in molecular weight in the final polymerization reactor is expressed by reduced viscosity, the range of the following formula (2) is preferable. Q / P is preferably 1.5 or more, more preferably 1.6 or more, still more preferably 1.7 or more, and on the other hand, it is preferably 3.0 or less, more preferably 2.9. Hereinafter, it is more preferably 2.8 or less.

1.5 ≦ Q / P ≦ 3.0 (2)
(P: reduced viscosity of the reaction liquid at the outlet of the reactor immediately before the final polymerization reactor, Q: reduced viscosity of the reaction liquid at the outlet of the final polymerization reactor)

  By setting Q / P to the upper limit value or less, it is possible to suppress the thermal history from becoming excessive in the final polymerization reactor and to prevent the color tone of the resulting resin from deteriorating. Further, by setting Q / P to the lower limit value or more, it is possible to suppress an excessive increase in the heat history before the final polymerization reactor, and to prevent deterioration of the color tone of the resin obtained in the same manner. Further, the molecular weight does not increase more than the target in the final polymerization reactor, and the reaction can be easily controlled.

  As described above, Q and P can be adjusted by adjusting temperature, pressure, residence time, catalyst amount or end group balance, etc., and Q / P can be controlled by appropriately combining these conditions. can do.

  For example, up to the reactor immediately before the final reactor, the temperature is decreased, the pressure is increased, the residence time is shortened, P is decreased, and as it is, Q is simultaneously decreased. The Q / P can be increased by decreasing the pressure in the reactor and keeping Q constant.

  In ordinary polycarbonate polymerization, in the case of a vertical stirring reactor, the amount of liquid in the reactor is increased / decreased according to the amount of reaction liquid processed (the amount of resin produced) to control the appropriate residence time. . However, since the final polymerization reactor has a very high melt viscosity of the reaction liquid, it is difficult to control the amount of liquid in the reactor, so the final polymerization reactor is suitable for the throughput of the reaction liquid. It is preferable to set a large capacity.

  In the case of a polycarbonate using a fluorene-based dihydroxy compound used in the present invention, it is more easily decomposed than bisphenols used in ordinary polycarbonates, and therefore, the liquid volume is more severely adjusted.

  For this reason, it is preferable that the said final polymerization reactor in this invention satisfy | fills following formula (4). V / A is preferably 2 or more, more preferably 3 or more, and on the other hand, it is preferably 13 or less, more preferably 10 or less.

2 ≦ V / A ≦ 13 (4)
[V: Horizontal reactor volume (L), A: Reaction liquid throughput (kg / hr)]

  By setting V / A to be equal to or less than the above upper limit value, it is possible to prevent the capacity of the reactor from becoming excessive with respect to the amount of the reaction liquid, and when the residence time is to be shortened, the liquid volume in the reactor is reduced. It is restrained, it can suppress that a reaction liquid stops flowing into the exit of a reactor, and can improve the yield of pelletization. In addition, if the amount of liquid is increased beyond an appropriate amount, the residence time becomes too long, the color tone of the resulting resin is deteriorated, and the molecular weight is excessively higher than the target, making it difficult to control the reaction. Tend to be.

  On the other hand, by setting V / A to be equal to or higher than the lower limit, the residence time is not excessively shortened, and the molecular weight can be improved to a desired level. Further, the surface renewability of the reaction solution is improved, residual low molecular components such as monohydroxy compounds (for example, phenol) can be reduced, and the quality of the resulting resin can be improved.

  In order to adjust V / A, for example, after determining the horizontal reactor vessel V to be used, V / A is reduced by increasing the reaction solution throughput A, and V is reduced by reducing the reaction solution throughput A. / A increases.

  By the way, when manufacturing the polycarbonate of this invention using substituted diphenyl carbonates, such as diphenyl carbonate or ditolyl carbonate, as said carbonic acid diester, the phenol or substituted phenol which is a monohydroxy compound byproduces, and remains in a polycarbonate. It is inevitable.

  However, these monohydroxy compounds such as phenol and substituted phenol may cause odor during molding. The polycarbonate obtained by the usual 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 1500 ppm or more. Note that these monohydroxy compounds may have a substituent depending on the raw material used, and may have, for example, an alkyl group having 5 or less carbon atoms.

  In order to reduce the residual low molecular components in the resin, including such a monohydroxy compound, it is effective to reduce the pressure in the final polymerization reactor as much as possible and distill it off. However, since the aliphatic polycarbonate using the fluorene-based dihydroxy compound or the dihydroxy compound having a cyclic ether structure as a monomer has a larger reaction equilibrium constant than the conventional aromatic polycarbonate using bisphenol A as a monomer, The molecular weight increase rate in the latter stage reaction is fast. For this reason, if the pressure is lowered too much, the reaction is promoted too much, so that the reaction tends to be difficult to control.

  In the production method of the present invention, the reaction rate is usually maximized when the amount of the hydroxy terminal is equal to the amount of the phenyl carbonate terminal represented by the following structural formula (8). By increasing the amount of phenyl carbonate and increasing the amount of phenyl carbonate terminals, it is possible to moderate the viscosity increase rate and reduce the pressure in the final polymerization reactor. 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 diester carbonate charge to the total dihydroxy compound is more preferably 0.995 or more, while more preferably 1.25 or less.

  By making the molar ratio of the carbonic acid diester 0.990 or more, disappearance of the hydroxy terminal in the subsequent reaction can be suppressed, and the desired molecular weight can be achieved. By setting the molar ratio of the carbonic acid diester to 1.030 or less, an increase in the hydroxy terminal is suppressed, and the thermal stability of the resulting resin is improved.

  By controlling the terminal balance in this way, it is possible to control the rate of viscosity increase in the final polymerization reactor, and the pressure in the final polymerization reactor can be reduced. The pressure in the final polymerization reactor is preferably 2 kPa or less, more preferably 1.5 kPa or less, and still more preferably 1.0 kPa or less. In addition, although it is so preferable that it is low, in many cases, it will become the limit of pressure reduction substantially at 10 Pa.

  Thus, the amount of hydroxy end groups of the polycarbonate resin obtained by polycondensation according to the present invention is preferably such that the amount of all hydroxy end groups in the reaction solution at the outlet of the final polymerization reactor is 1000 ppm or less. . More preferably, it is 900 ppm or less, Most preferably, it is 800 ppm or less.

  The smaller the amount of hydroxy end groups the resulting polycarbonate resin has, the better from the viewpoint of thermal stability, but if the hydroxy ends completely disappear, there is a risk that the reaction will peak and the desired molecular weight may not be reached. The amount of all hydroxy end groups in the reaction solution at the outlet of the final polymerization reactor is preferably 50 ppm or more.

  The amount of the monohydroxy compound contained in the polycarbonate resin obtained by polycondensation in the present invention is preferably 1500 ppm or less, more preferably 1000 ppm or less, at the reactor outlet immediately before the final polymerization reactor. Especially preferably, it is 500 ppm or less. However, it is difficult to remove completely industrially, and the lower limit of the content of the monohydroxy compound is usually 1 ppm.

  Furthermore, the amount of the monohydroxy compound contained in the polycarbonate resin is preferably 10 ppm or more and 3 wt% or less in the reaction solution at the outlet of the reactor immediately before the final polymerization reactor. Moreover, 1500 ppm or less is preferable at the exit of the final polymerization reactor, more preferably 1000 ppm or less, and particularly preferably 500 ppm or less. However, it is difficult to remove completely industrially, and the lower limit of the content of the monohydroxy compound is usually 1 ppm.

  Monohydroxy compounds at the outlet of these reactors are removed by making the reactor pressure as low as possible. Furthermore, the monohydroxy compound in resin can further be reduced by supplying a reaction liquid to an extruder after a polymerization reaction and performing vacuum devolatilization.

  As described above, since the polycarbonate obtained by polycondensation of the dihydroxy compound containing the dihydroxy compound having the fluorene structure according to the present invention has lower thermal stability than the conventional aromatic polycarbonate, the reaction temperature is set as low as possible. However, the viscosity of the reaction solution is higher than that of the conventional polycarbonate.

  When the viscosity of the reaction solution increases, the reaction solution may wrap around the stirring shaft and not sag. When a horizontal reactor having a plurality of horizontal rotation axes is used inside the final polymerization reactor, in order to stably extract the reaction solution from the reactor, the number of revolutions of the stirring blade is set according to the melt viscosity of the reaction solution. It is necessary to set appropriately, and it is preferable to set in the range of the following formula (3).

500 ≦ ωμ ≦ 20000 (3)
[Ω: stirring blade rotation speed (rpm), μ: melt viscosity (Pa · s) of the reaction liquid at the outlet of the horizontal reactor]

  In addition, since the said conditions do not depend on the shaft diameter of a stirring blade, it is not related to the reaction scale. ωμ is preferably 500 or more, on the other hand, preferably 20000 or less, more preferably 15000 or less.

  By setting ωμ to the upper limit value or less, it is possible to suppress the reaction liquid from being wrapped around the stirring shaft, to improve the yield in the pelletizing step, and to prevent the increase of foreign substances in the resin. . By setting ωμ to 500 or more, the stirring efficiency becomes sufficient, the amount of residual low molecular components in the reaction solution is suppressed from increasing, and the reaction solution is prevented from staying on the reactor wall surface and deteriorating in color. be able to.

  As a method for controlling ωμ, for example, when the pressure of the horizontal reactor is kept constant and the molecular weight of the reaction solution is increased by increasing the pressure, the melt viscosity μ of the reaction solution increases and ωμ increases. Therefore, ωμ can be kept within a preferable range by reducing the stirring blade rotational speed ω with increasing molecular weight.

  In order to stably produce a polycarbonate resin having a high molecular weight without deteriorating the quality such as color tone, the stirring blade rotational speed ω is preferably less than 5 rpm, more preferably less than 4 rpm, and particularly preferably 3. Less than 5 rpm, especially less than 3 rpm is optimal. If the rotating speed of the stirring blade is excessively high, local shear heat generation due to stirring will rise, not only deteriorating the quality of the polycarbonate resin, but also the tangling of the polycarbonate resin to the stirring blade will become strong, and the polycarbonate resin from the horizontal reactor will The discharge becomes unstable, which may cause the trouble that the stabilization of the molecular weight is hindered or the strand at the time of pelletization is cut halfway.

  On the other hand, if the stirring blade rotational speed ω is too small, the interface renewability is deteriorated, the increase in molecular weight is hindered, and a polycarbonate resin having a molecular weight suitable for a stretched film may not be obtained. Above, more preferably 0.5 rpm or more, particularly preferably 0.8 rpm or more.

  The polycarbonate obtained by polycondensation according to the present invention may be subjected to the above-mentioned polycondensation reaction and then filtered through a filter in a molten state. In particular, in order to remove low molecular weight components contained in the resin, or to add and knead a heat stabilizer or 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.

<Steps after polycondensation reaction>
In the production 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 polymerization reactor is extracted in a molten state using a gear pump or a screw, and filtered through a filter, and the final polymerization reactor is melted and uniaxially or biaxially extruded. The resin is supplied to the machine, melt-extruded, filtered through a filter, cooled and solidified in the form of a strand, pelletized with a rotary cutter, etc., uniaxial or biaxial in the molten state from the final polymerization reactor After the resin is supplied to the extruder 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 pellets From the final polymerization reactor in a molten state, and cooled and solidified in the form of strands without passing through an extruder, and then once pellets After allowed to supplies pellets to an extruder uniaxial or biaxial, after melt extrusion, and filtered through a filter, which is solidified by cooling in the form of a strand method or the like for pelletizing.

  Above all, in order to minimize the heat history and suppress the deterioration of hue or molecular weight, or the thermal deterioration, the resin is supplied from the final polymerization reactor to the uniaxial or biaxial extruder in the molten state. After the melt extrusion, 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.

  In the present invention, the form of the extruder is not limited, but it is usually preferable to use a single or twin screw extruder. Among them, a twin screw extruder is preferable for improving the devolatilization performance described later or for uniform kneading of the additive. In this case, the rotation direction of the shaft may be different or the same, but the same direction is preferable from the viewpoint of kneading performance. The use of an extruder can stabilize the supply of polycarbonate resin to the filter.

  In addition, in the polycarbonate obtained by polycondensation as described above, it is usually a by-product in the raw material monomer and transesterification reaction that may adversely affect the product due to hue or heat stability, and further bleed out. Low molecular weight compounds such as monohydroxy compounds or polycarbonate oligomers remain, but they are devolatilized by using an extruder having a vent port, preferably by reducing the pressure from the vent port using a vacuum pump or the like. It is also possible to remove it. 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.

  Further, in the above-mentioned extruder, a heat stabilizer, a neutralizing agent, an ultraviolet absorber, a release agent, a colorant, an antistatic agent, a lubricant, a lubricant, a plasticizer, a compatibilizing agent or Flame retardants can be added and kneaded.

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

  Examples of the form of the filter include known ones such as a candle type, a pleat type, and a leaf disk type. Among these, a leaf disk type that can provide a large filtration area with respect to the storage container of the filter is preferable, and a plurality of combinations are preferably used so that a large filtration area can be obtained.

  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 medium 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 or SUS316L with a low iron content is particularly preferable. .

  As the type of weaving, a non-woven fabric type can be used in addition to a regular weaving portion of the foreign matter collecting portion such as a plain weave, a twill weave, a plain tatami mat or a twill mat weave. 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 99 μm or less when it is particularly desired to reduce foreign matter, as 99% filtration accuracy.

  In addition, if the aperture is reduced, the pressure loss in the filter increases, and the filter may be damaged, or the polycarbonate resin may be deteriorated by shearing heat generation. Therefore, the filtration accuracy of 99% is 1 μm or more. Preferably there is.

Here, the aperture defined as 99% filtration accuracy is the value of χ when the βχ value represented by the following formula (9) determined in accordance with ISO 16889 (2008) is 1000. say.
βχ = (number of particles on the primary side larger than χμm) / (number of particles on the secondary side larger than χμm) …… (9)
(Here, “primary side” indicates before filtration with a filter, and “secondary side” indicates after filtration.)

  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 includes, for example, a method in which a filter is immersed in an acid such as nitric acid or an acid is passed through the filter to form a passive state on the surface, and roasting (heating) in the presence of water vapor or oxygen ) The method of processing, the method of using these together, etc. are mentioned. Among them, it is preferable to perform both nitric acid treatment and roasting.

  The roasting temperature is preferably 350 ° C. to 500 ° C., more preferably 350 ° C. to 450 ° C., and the roasting time is preferably 3 hours to 200 hours, more 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, more preferably 10% to 30% by weight, and the temperature during the treatment is preferably 5 ° C to 100 ° C, More preferably, it is 50 to 90 ° C., and the treatment time is preferably 5 to 120 minutes, more preferably 10 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 production 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. Alternatively, it is a 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 production method of the present invention, it is preferable to dispose 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 preferable to carry out in a clean room with higher cleanliness than class 6.

  The polycarbonate resin filtered through the filter is cooled and solidified and pelletized with a rotary cutter or the like, and it is preferable to use a cooling method such as air cooling or water cooling during the pelletization. As the air used for air cooling, it is preferable to use air from which foreign matters in the air have been removed in advance with a hepa filter or the like to prevent reattachment of foreign matters in the air.

  When using water cooling, it is preferable 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.

<Step before polycondensation reaction>
On the other hand, in the production 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 raw material filter at that time may be any type such as a basket type, a disc type, a leaf disc type, a tube type, a flat cylindrical type or a pleated cylindrical type. A pleated type having a large filtration area is preferable.

  Moreover, as a filter medium which comprises the said raw material filter, any, such as a metal wind, a laminated metal mesh, a metal nonwoven fabric, or a porous metal plate, may be sufficient. From the viewpoint of filtration accuracy, a laminated metal mesh or a metal nonwoven fabric is preferred, and among them, a type in which a metal nonwoven fabric is sintered and fixed is preferred.

  There are no particular restrictions on the material of the raw material filter, and metal or resin ceramics can be used. However, from the viewpoint of heat resistance or color reduction, a metal filter having an iron content of 80% or less is used. Among these, stainless steel such as SUS304, SUS316, SUS316L, or 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 μm. When the aperture of the filter in the downstream unit is D μm, C is preferably larger than D (C> D) in at least one combination. When the said conditions are satisfy | filled, it becomes difficult to obstruct | occlude a filter and it can aim at reduction of the replacement frequency of the said raw material filter.

  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. In addition, the opening of the said raw material filter said here is also determined based on the above-mentioned ISO16889 (2008).

  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. It is preferable that it is 200 degreeC, More preferably, it is 100 to 150 degreeC.

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

<Example of manufacturing equipment>
Next, an example of the manufacturing 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, or catalyst described below is an example of an embodiment of the present invention, and the present invention is not limited to the example described below.

  FIG. 1 is a diagram showing an example of a manufacturing apparatus used in the manufacturing method of the present invention. In the production apparatus shown in FIG. 1, the polycarbonate of the present invention comprises a raw material preparation step for preparing the raw material dihydroxy compound and carbonic acid diester, and a polycondensation reaction of these raw materials in a molten state using a plurality of reactors. It is manufactured through a process. The distillate produced in the polycondensation step is liquefied by the condensers 12a, 12b, 12c and 12d and collected in the distillate collection tank 14a.

  After the polycondensation step, the step of devolatilizing and removing unreacted raw materials or reaction by-products in the polymerization reaction solution, the step of adding a heat stabilizer, a release agent or a colorant, or the polycarbonate into pellets of a predetermined particle size Through the forming step, polycarbonate pellets are formed.

  In the following, BHEPF (9,9-bis (4- (2-hydroxyethoxy) phenyl) fluorene), ISB (specific dihydroxy compound) and polyethylene glycol 1000 (PEG1000) are used as the raw material dihydroxy compound, and carbonic acid diester as the raw material. As an example, a case where DPC is used and magnesium acetate is used as a catalyst will be described.

  First, in the raw material preparation step, a DPC melt prepared at a predetermined temperature in a nitrogen gas atmosphere is supplied from the raw material supply port 1a to the raw material mixing tank 2a. The powdered BHEPF is supplied from the raw material supply port 1b, and then the ISB melt and the PEG 1000 melt measured in a nitrogen gas atmosphere are supplied from the raw material supply ports 1c and 1d to the raw material mixing tank 2a. Continuously supplied. 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, magnesium acetate aqueous solution is continuously supplied as a raw material catalyst from the catalyst supply port 1e in the middle of the transfer piping of the raw material mixed melt.

  In the polycondensation step of the production apparatus of FIG. 1, a first vertical stirring 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 polymerization reactor in the present invention, and the third vertical stirring reactor 6c corresponds to the reactor immediately before the final polymerization reactor. To do.

  The first vertical stirring 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.

  Since the first vertical stirring reactor 6a and the second vertical stirring reactor 6b may have a particularly large amount of supplied heat, the internal heat exchanger 8a, respectively, may be used so that the temperature of the heating medium does not become excessively high. 8b 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 temperature of the heating medium 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 withdrawn 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, or the like is 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 a product bag 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 of each reactor and the temperature and pressure of the heating medium 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: 210 ° C. to 260 ° C., pressure: 2 kPa to 10 Pa, temperature of heating medium 210 to 260 ° 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 is produced under temperature and pressure conditions suitable for performing 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. In the present invention, it is necessary to set the internal temperature of the third vertical stirring reactor 6c, which is the previous reactor of the horizontal stirring reactor 6d, to 200 ° C. or higher and lower than 225 ° C.

  The horizontal stirring reactor 6d has one or two or more horizontal rotation shafts, such as a disk shape, a wheel shape, a saddle shape, a rod shape, or a window frame shape extending vertically 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 two or more types 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.

  An example of a stirrer having a biaxial glasses-type stirring blade 7d as the horizontal stirring reactor 6d is shown in FIGS. FIG. 2 is a perspective view of the biaxial glasses-type stirring blade 7d, and FIG. 3 is a schematic view of the horizontal stirring reactor 6d containing the same, as viewed from above.

  The stirring blades 21A and 21B are in a phase difference of 90 degrees from each other, and the respective shafts 22A and 22B are rotated in reverse. As a result, the tip portions of the respective stirring blades 21A and 21B rotate while scraping off the resin adhered to the other stirring blades 21B and 21A. A plurality of such stirring blades 21A, 21B are connected in the axial direction.

  The reaction temperature in the latter reaction step is usually preferably 200 to 260 ° C., more preferably 210 to 250 ° C., and the reaction pressure is usually preferably 13.3 kPa to 10 Pa, more preferably. Is 2 kPa to 30 Pa, more preferably 1 kPa to 50 Pa.

  In the production method of the present invention, the residence time of the reaction liquid can be appropriately set 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, and By suppressing shearing heat generation, the temperature can be lowered, and a polycarbonate having improved mechanical properties and excellent mechanical properties can be obtained.

  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 production 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.

  The molecular weight of the polycarbonate of the present invention obtained by polycondensation in this way can be expressed by reduced viscosity, preferably 0.20 dL / g or more, more preferably 0.30 dL / g or more. On the other hand, it is preferably 1.20 dL / g or less, more preferably 1.00 dL / g or less, and further 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, and if it is too large, the fluidity at the time of molding is lowered, and the productivity or moldability tends 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.

According to the production method of the present invention, a resin having little coloring and few foreign matters can be obtained while being a polycarbonate having the structure of the above formula (1). Specifically, a foreign matter having a maximum length of 20 μm or more contained in a film having a thickness of 30 μm ± 5 μm formed from the polycarbonate resin of the present invention is preferably 1000 / m ² or less, more preferably 500 / m ^2. Hereinafter, it can be most preferably 200 pieces / m ² or less.

<Raw materials and catalysts>
Hereinafter, raw materials and catalysts that can be used for the polycarbonate of the present invention will be described.

(Dihydroxy compound)
The dihydroxy compound used for the production of the polycarbonate of the present invention includes a dihydroxy compound having a fluorene structure (fluorene-based dihydroxy compound). From the viewpoint of heat resistance, mechanical strength, optical properties, or polymerization reactivity of the obtained polycarbonate, those represented by the following formula (1) having a 9,9-diphenylfluorene structure are preferable.

In the general formula (1), R ^{1 to} R ⁴ are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted carbon atom having 6 to 20 carbon atoms. It represents a cycloalkyl group or a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, and the same or different groups are arranged as each of the four substituents on each benzene ring. X is a substituted or unsubstituted alkylene group having 2 to 10 carbon atoms, a substituted or unsubstituted cycloalkylene group having 6 to 20 carbon atoms, or a substituted or unsubstituted carbon atom having 6 to 20 carbon atoms. Represents an arylene group. m and n are each independently an integer of 0 to 5.

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

  Specifically, for example, 9,9-bis [4- (2-hydroxyethoxy) phenyl] fluorene, 9,9-bis (4-hydroxyphenyl) fluorene, 9,9-bis (4-hydroxy-2-) Methylphenyl) fluorene, 9,9-bis [4- (2-hydroxypropoxy) phenyl] fluorene, 9,9-bis [4- (2-hydroxyethoxy) -3-methylphenyl] fluorene, 9,9-bis [4- (2-hydroxypropoxy) -3-methylphenyl] fluorene, 9,9-bis [4- (2-hydroxyethoxy) -3-isopropylphenyl] fluorene, 9,9-bis [4- (2- Hydroxyethoxy) -3-isobutylphenyl] fluorene, 9,9-bis [4- (2-hydroxyethoxy) -3-tert-butylphenyl] Luolene, 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 and 9, And 9-bis [4- (3-hydroxy-2,2-dimethylpropoxy) phenyl] fluorene.

  The polycarbonate of the present invention may contain a structural unit derived from a dihydroxy compound other than the fluorene-based dihydroxy compound in order to adjust the desired optical properties. From the viewpoint of optical properties such as moderate birefringence or low photoelastic coefficient, heat resistance or mechanical strength, a dihydroxy compound having a site represented by the above formula (5) in a part of the structure (specific dihydroxy compound) is preferable. .

  Specific examples include oxyalkylene glycols, dihydroxy compounds having an ether group bonded to an aromatic group in the main chain, and dihydroxy compounds having a cyclic ether structure.

  Specific examples of the specific dihydroxy compound having a site represented by the above formula (5) in a part of the structure include, for example, oxyalkylene glycols and dihydroxy compounds having an ether group bonded to an aromatic group in the main chain. And dihydroxy compounds having a cyclic 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 2,2-bis [4- (2-hydroxyethoxy) phenyl] propane and 2,2-bis [4- (2 -Hydroxypropoxy) phenyl] propane, 1,3-bis (2-hydroxyethoxy) benzene, 4,4′-bis (2-hydroxyethoxy) biphenyl, bis [4- (2-hydroxyethoxy) phenyl] sulfone, and the like. Can be mentioned.

  Examples of the dihydroxy compound having a cyclic ether structure include a dihydroxy compound represented by the following formula (10) and a spiroglycol represented by the following formula (11) or the following formula (12).

  The “cyclic ether structure” of the “dihydroxy compound having a cyclic ether structure” means an organic compound 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 formula (10) include isosorbide (ISB), isomannide, and isoidet, which have a stereoisomeric relationship. These may be used individually by 1 type and may be used in combination of 2 or more type.

  Among these dihydroxy compounds, the hydroxy compounds represented by the formula (10), (11) or (12) are representative from the viewpoint of easy availability, handling, reactivity during polymerization, and hue of the obtained polycarbonate. The dihydroxy compound having a cyclic ether structure is preferred, and the dihydroxy compound represented by the above formula (10) or the dihydroxy compound having two cyclic ether structures such as spiroglycol represented by the following formula (11) is more preferred. Anhydrosugar alcohol which is a dihydroxy compound having two sugar-derived cyclic ether structures, such as a dihydroxy compound represented by the following formula (10), is particularly preferable.

  Of these specific dihydroxy compounds, it is preferable to use a dihydroxy compound having no aromatic ring structure from the viewpoint of optical properties of the polycarbonate. Among them, anhydrous sugar alcohols such as dihydroxy compounds represented by the above formula (10) obtained by dehydrating condensation of sorbitol produced from various starches that are abundant as plant-derived resources are available. And most preferable from the viewpoints of ease of production, light resistance, optical properties, moldability, heat resistance and carbon neutral.

  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 dihydroxy compound having the bond structure of the formula (2) may contain a stabilizer such as a reducing agent, an antioxidant, an oxygen scavenger, a light stabilizer, an antacid, a pH stabilizer or a heat stabilizer. . In particular, since the specific dihydroxy compound of the present invention is easily altered under acidic conditions, it is preferable to include a basic stabilizer.

  Examples of the basic stabilizer 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). Acid salts, borates and fatty acid salts, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, trimethylethylammonium hydroxide, trimethylbenzylammonium hydroxide, trimethylphenylammonium hydroxide, Triethylmethylammonium hydroxide, triethylbenzylammonium hydroxide, triethylphenylammonium Basic ammonium compounds such as nium hydroxide, tributylbenzylammonium hydroxide, tributylphenylammonium hydroxide, tetraphenylammonium hydroxide, benzyltriphenylammonium hydroxide, methyltriphenylammonium hydroxide and butyltriphenylammonium hydroxide, diethylamine , Dibutylamine, triethylamine, morpholine, N-methylmorpholine, pyrrolidine, piperidine, 3-amino-1-propanol, ethylenediamine, N-methyldiethanolamine, diethylethanolamine, 4-aminopyridine, 2-aminopyridine, N, N- Dimethyl-4-aminopyridine, 4-diethylaminopyridine, 2-hydroxypyridine, 2-methoxy Amine compounds such as pyridine, 4-methoxypyridine, 2-dimethylaminoimidazole, 2-methoxyimidazole, imidazole, 2-mercaptoimidazole, 2-methylimidazole and aminoquinoline, and di- (tert-butyl) amine, 2, Examples include hindered amine compounds such as 2,6,6-tetramethylpiperidine. Among the stabilizers, tetramethylammonium hydroxide, imidazole or hindered amine stabilizers are preferable from the viewpoint of stabilizing effect.

  The content of these basic stabilizers in the dihydroxy compound is not particularly limited. However, the dihydroxy compound having the structure represented by the formula (2) used in the present invention is unstable in an acidic state, and thus the above-mentioned stability. It is preferable to add a stabilizer so that the pH of the aqueous solution of the dihydroxy compound containing the agent is 7 or more.

  If the amount is too small, there is a possibility that the effect of preventing the alteration of the fluorene-based dihydroxy compound or the specific dihydroxy compound of the present invention may not be obtained, and if the amount is too large, the fluorene-based dihydroxy compound or the specific dihydroxy compound may be modified. Therefore, it is usually preferably 0.0001% by weight to 1% by weight and more preferably 0.001% by weight to 0.1% by weight with respect to each dihydroxy compound used in the present invention.

  In addition, since the specific dihydroxy compound having the structure represented by the formula (2) is apt to be gradually oxidized by oxygen, moisture is not mixed to prevent decomposition by oxygen during storage or handling during manufacture. In addition, it is preferable to use an oxygen scavenger or to have 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.

  The polycarbonate of the present invention may contain a structural unit derived from a dihydroxy compound other than the fluorene-based dihydroxy compound and the specific dihydroxy compound (hereinafter may be referred to as “other dihydroxy compound”).

  Examples of the other dihydroxy compounds include linear aliphatic hydrocarbon dihydroxy compounds, linear branched aliphatic hydrocarbon dihydroxy compounds, alicyclic hydrocarbon dihydroxy compounds, 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, 1,2 -Butanediol, 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, and tricyclodecanedi. Methanol, pentacyclopentadecane dimethanol, 2,6-decalin dimethanol, 1,5-decalin dimethanol, 2,3-decalin dimethanol, 2,3-norbornane dimethanol, 2,5-norbornane dimethanol, 1, Examples thereof include dihydroxy compounds derived from terpene compounds such as 3-adamantane dimethanol and limonene.

  Examples of the aromatic bisphenols include 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane, and 2,2-bis (4 -Hydroxy-3,5-diethylphenyl) propane, 2,2-bis (4-hydroxy- (3,5-diphenyl) phenyl) propane, 2,2-bis (4-hydroxy-3,5-dibromophenyl) Propane, 2,2-bis (4-hydroxyphenyl) pentane, 2,4′-dihydroxy-diphenylmethane, bis (4-hydroxyphenyl) methane, bis (4-hydroxy-5-nitrophenyl) methane, 1,1- Bis (4-hydroxyphenyl) ethane, 3,3-bis (4-hydroxyphenyl) pentane, 1,1-bis (4-hydroxyphenyl) Nyl) cyclohexane, bis (4-hydroxyphenyl) sulfone, 2,4′-dihydroxydiphenylsulfone, bis (4-hydroxyphenyl) sulfide, 4,4′-dihydroxydiphenyl ether and 4,4′-dihydroxy-3,3 ′ -Dichlorodiphenyl ether etc. are mentioned.

  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, and after combining two or more kinds, the fluorene-based dihydroxy compound or the specific dihydroxy compound. You may use together.

  Among these, from the viewpoint of the optical properties 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 the polycarbonate of the present invention is particularly 1,3-propanediol, 1,4-butanediol, 1,5-heptanediol, 1,6-hexanediol and the like. A straight-chain aliphatic hydrocarbon dihydroxy compound having 3 to 6 carbon atoms and having hydroxy groups at both ends is preferred.

  As the alicyclic hydrocarbon dihydroxy compound, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol or tricyclodecane dimethanol is particularly preferable, and 1,2-cyclohexanedimethanol is more preferable. It is a dihydroxy compound having a cyclohexane structure such as 2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, or 1,4-cyclohexanedimethanol.

(Carbonated diester)
The polycarbonate of the present invention can be obtained by polycondensation by a transesterification reaction using a dihydroxy compound containing the fluorene-based dihydroxy compound and a carbonic acid diester as raw materials.

  As a carbonic acid diester used, what is normally represented by following formula (13) is mentioned. These carbonic acid diesters may be used alone or in combination of two or more.

In the formula (13), 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 May be the same or different. A preferable example of A ¹ and A ² is a substituted or unsubstituted aromatic hydrocarbon group, and a more preferable example is an unsubstituted aromatic hydrocarbon group.

  Examples of the carbonic acid diester represented by the formula (13) include substituted diphenyl carbonates such as diphenyl carbonate (DPC) and ditolyl carbonate, dimethyl carbonate, diethyl carbonate, and di-t-butyl carbonate. Among them, preferred is diphenyl carbonate or substituted diphenyl carbonate, and particularly preferred is diphenyl carbonate.

  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)
The polycarbonate of the present invention is produced by transesterifying the dihydroxy compound containing the specific dihydroxy compound and the carbonic acid diester represented by the formula (13) 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 the transesterification reaction, polycondensation is carried out in the presence of a 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 a catalyst or a polymerization catalyst). Can greatly influence the reaction rate or 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. For example, metal compounds of Group 1 or Group 2 (hereinafter simply referred to as “Group 1” or “Group 2”) in the long-period periodic table, as well as basic boron compounds, basic phosphorus compounds, and basic ammonium compounds And basic compounds such as 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 phenide boron, potassium phenide boron, lithium phenide boron, cesium phenide boron, sodium benzoate, potassium benzoate, lithium benzoate, cesium benzoate, hydrogen phosphate 2 Thorium, 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, Examples include cesium alcoholate, phenolate, disodium salt of bisphenol A, dipotassium salt, dilithium salt, and dicesium salt. Of these, lithium compounds are preferred from the viewpoint of polymerization activity and the hue of the resulting polycarbonate.

  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. Examples thereof include magnesium, strontium carbonate, calcium acetate, barium acetate, magnesium acetate, strontium acetate, calcium stearate, barium stearate, magnesium stearate, and strontium stearate. Of these, magnesium compounds, calcium compounds and barium compounds are preferred, and magnesium compounds and / or calcium compounds are more preferred from the viewpoint of polymerization activity and the hue of the resulting polycarbonate.

  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 and 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 usually preferably 0.1 μmol to 300 μmol, more preferably 0.5 μmol to 100 μmol, per 1 mol of all dihydroxy compounds used in the polymerization.

  In particular, when a compound containing at least one metal selected from the group consisting of Group 2 and lithium in the long-period periodic table is used, particularly when a magnesium compound and / or a calcium compound is used, the amount of metal is The amount is preferably 0.1 μmol or more, more preferably 0.3 μmol or more, particularly preferably 0.5 μmol or more per 1 mol of the dihydroxy compound. Moreover, as an upper limit, 40 micromol is preferable normally, More preferably, it is 30 micromol, More preferably, it is 20 micromol.

  However, the specific dihydroxy compound having a fluorene moiety used in the present invention may contain sulfur impurities derived from the catalyst used in the synthesis, and has the effect of deactivating the polymerization catalyst. The polymerization catalyst to be added is preferably used in excess of the above range by the amount deactivated.

  When the total sulfur element content per mol of all dihydroxy compounds used in the reaction is A μmol and the amount of metal element of the polymerization catalyst is B μmol, it is preferable to be within the range of the following formula (14).

  0.1 ≦ B / A ≦ 2 (14)

  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. For this reason, there is a high possibility that the hue of the resulting polycarbonate will deteriorate, and the unreacted raw material may volatilize during the polymerization, causing the molar ratio of the dihydroxy compound and the carbonic acid diester to collapse and not reaching the desired molecular weight. is there.

  On the other hand, when the amount of the polymerization catalyst used is too large, an undesirable side reaction may occur at the same time, which may lead to deterioration of the hue of the resulting polycarbonate or coloring of the resin during molding.

  Among group 1 metals, sodium, potassium, and cesium may adversely affect the hue when contained in a large amount in 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 the metal compound in the polycarbonate is preferably 2 μmol or less, more preferably 1 μmol or less, and even more preferably 0.5 μmol or less, per 1 mol of the total dihydroxy compound as the metal amount.

<Physical properties and uses of polycarbonate>
The molecular weight of the polycarbonate of the present invention thus obtained can be represented by a reduced viscosity, and the reduced viscosity is preferably 0.20 dL / g or more, more preferably 0.30 dL / g or more. On the other hand, it is preferably 1.00 dL / g or less, more preferably 0.80 dL / g or less, and further preferably 0.70 dL / g or less.

  If the reduced viscosity of the polycarbonate is too low, the mechanical strength of the molded product may be reduced. If it is too high, the fluidity at the time of molding tends to decrease, and the productivity or moldability tends to decrease. The reduced viscosity is measured by using a Ubbelohde viscometer at a temperature of 20.0 ° C. ± 0.1 ° C., precisely adjusting the polycarbonate concentration to 0.6 g / dL using methylene chloride as a solvent.

  The glass transition temperature of the polycarbonate resin in the present invention is preferably 100 ° C. or higher and 160 ° C. or lower, more preferably 110 ° C. or higher and 150 ° C. or lower. If the glass transition temperature is excessively low, the heat resistance tends to deteriorate, and there is a possibility of causing a dimensional change after film formation.

  Moreover, when polycarbonate resin is used as a retardation film and laminated with a polarizing plate, the image quality may be lowered. On the other hand, if the glass transition temperature is excessively high, the molding stability may be deteriorated, such as unevenness of the film thickness at the time of film formation or the film becomes brittle, and the transparency of the film may be impaired.

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

  As a method for producing a film using the polycarbonate resin of the present invention, a melt extrusion method is preferred from the viewpoint of productivity. In the melt extrusion method, a method of extruding a resin using a T die and sending it to a cooling roll is preferably used. The melting temperature at this time is determined from the molecular weight, Tg, melt flow characteristics, etc. of the polycarbonate, but is preferably in the range of 150 ° C. to 300 ° C., more preferably in the range of 170 ° C. to 280 ° C.

  If the temperature is too high, problems such as coloring due to thermal deterioration, appearance defects due to the occurrence of foreign matter or silver, or die lines from the T-die are likely to occur. If the temperature is too low, the viscosity increases and polymer orientation or stress strain tends to remain.

  The retardation value of the formed film is preferably 20 nm or less, more preferably 10 nm or less. When the retardation value of the film is larger than this, it is not preferable because when the film is stretched to obtain a retardation film, the dispersion of the retardation value in the film surface increases.

  A solution casting method can also be used as a method for producing the film. As the solvent, for example, methylene chloride, chloroform, 1,2-dichloroethane, 1,1,2,2-tetrachloroethane, dioxolane, dioxane, tetrahydrofuran, toluene or methyl ethyl ketone is preferable.

  The amount of residual solvent in the film obtained by the solution casting method is preferably 2% by weight or less, more preferably 1% by weight or less. By setting it to 2% by weight or less, it is possible to prevent a decrease in the glass transition temperature of the film due to a large amount of residual solvent, which is preferable in terms of heat resistance.

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

  A retardation film can be obtained by stretching and orienting the unstretched film thus obtained. Examples of the stretching method include known methods such as longitudinal uniaxial stretching and lateral uniaxial stretching using a tenter, and simultaneous biaxial stretching and sequential biaxial stretching in combination thereof.

  Stretching may be performed batchwise, but it is preferable in terms of productivity to be performed continuously. Further, a continuous retardation film with less variation in retardation within the film surface can be obtained compared to a batch system. The stretching temperature is preferably in the range of (Tg-20 ° C) to (Tg + 30 ° C), more preferably in the range of (Tg-10 ° C) to (Tg + 20 ° C) with respect to the glass transition temperature of the polycarbonate resin. It is.

  Although the draw ratio is determined by the target retardation value, it is preferably 1.05 to 4 times, more preferably 1.1 to 3 times in the longitudinal and lateral directions.

  The transparent film formed by molding the polycarbonate resin in the present invention preferably has a birefringence of 0.001 or more, and more preferably 0.0014 or more. When birefringence is excessively small, when a retardation film is used, in order to develop the same retardation, the film thickness must be increased, which may not be suitable for thin devices. In addition, the said birefringence is the value which measured the transparent film which carried out fixed uniaxial stretching at the glass transition temperature +15 degreeC extending | stretching temperature of the polycarbonate resin of this invention.

  The retardation film according to the present invention is used as a retardation plate for various liquid crystal display devices or organic EL display devices by laminating and laminating a known iodine-based or dye-based polarizing plate and an adhesive. Can be used.

  In the transparent film according to the present invention, the ratio of the retardation (Re450) measured at a wavelength of 450 nm to the retardation (Re550) measured at a wavelength of 550 nm is preferably 0.5 or more and 1.0 or less, and 0.70 or more and 1 0.0 or less is more preferable, and 0.80 or more and 0.95 or less is still more preferable.

  If the ratio is within the above range, an ideal phase difference characteristic can be obtained at each wavelength in the visible region. For example, a retardation film having such wavelength dependency is prepared as a quarter wavelength plate, and a circularly polarizing plate or the like can be manufactured by laminating with a polarizing plate, and polarization with less hue wavelength dependency. A board and a display device can be realized.

  On the other hand, when the ratio is out of the above range, the wavelength dependence of hue tends to increase, and optical compensation is not performed at all wavelengths in the visible region, or light passes through the polarizing plate or the display device. Problems such as coloring or reduced contrast can occur.

In general, "film" refers to a thin and flat product whose thickness is extremely small compared to the length and width and whose maximum thickness is arbitrarily limited, and is usually supplied in the form of a roll. In general, the term “sheet” refers to a product that is thin by definition in JIS and whose thickness is small and flat for the length and width. However, since the boundary between the “sheet” and the “film” is not clear and it is not necessary to distinguish the two in terms of the present invention, even if the term “film” is used in this specification, the “sheet” As a concept including “

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

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

  As the liquid crystal display device, a reflective liquid crystal display device including a reflective liquid crystal panel is preferable. A reflective liquid crystal display device comprising a polarizing film, a quarter-wave plate, and a liquid crystal cell including a liquid crystal layer between two substrates having transparent electrodes in this order. A display device with excellent image quality can be obtained by using it for a display device, particularly a polarizing film single-reflection type liquid crystal display device.

  As the reflective liquid crystal display device, a polarizing film, a retardation film, a substrate with a transparent electrode, a liquid crystal layer and a substrate with a scattering reflection electrode, a polarizing film, a scattering plate, a retardation film, and a transparent electrode A substrate, a liquid crystal layer, and a substrate with a specular reflective electrode, a polarizing film, a retardation film, a substrate with a transparent electrode, a liquid crystal layer, a substrate with a transparent electrode, and a reflective layer. .

  Further, the quarter-wave plate can be used in a liquid crystal display device having both a transmission type and a reflection type. Examples of the configuration of the liquid crystal display device include a polarizing film, a retardation film, a substrate with a transparent electrode, a liquid crystal layer, a substrate with a reflection / transmission electrode, a retardation film, a polarizing film, and a backlight system.

  Further, for example, in a reflective polarizing film made of cholesteric liquid crystal that reflects only the left or right circularly polarized light, if the circularly polarized light is used as an element for converting linearly polarized light, good linearly polarized light can be obtained in a wide band.

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

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 value of various manufacturing conditions and evaluation results in the following examples has a meaning as a preferable value of the upper limit or the lower limit in the embodiment of the present invention, and the preferable range is the above-described upper limit or lower limit value. A range defined by a combination of values of the following examples or values of the examples may be used.
The abbreviations of the compounds used in the description of the following examples are as follows.
BHEPF: 9,9-bis [4- (2-hydroxyethoxy) phenyl] fluorene [manufactured by Osaka Gas Chemical Co., Ltd.]... Sulfur element content of 5 ppm to 7 ppm was used.
-ISB: Isosorbide [Rocket Fleure, trade name: POLYSORB]
PEG # 1000: Polyethylene glycol Number average molecular weight 1000 [manufactured by Sanyo Chemical Industries, Ltd.]
・ DEG: Diethylene glycol [Mitsubishi Chemical Corporation]
CHDM: 1,4-cyclohexanedimethanol [New Nippon Rika Co., Ltd., trade name: SKY CHDM]
・ DPC: Diphenyl carbonate [Mitsubishi Chemical Corporation]
The composition analysis of polycarbonate and the evaluation of physical properties were performed by the following methods 1) to 8).

1) Content of monohydroxy compound (phenol) in 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 or 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: 260 nm
Eluent: Liquid A: 0.1% phosphoric acid aqueous solution, Liquid B: acetonitrile A / B = 40/60 (vol%) to A / B = 0/100 (vol%) in 10 minutes Gradient Flow rate: 1mL / min
Sample injection volume: 10 μL

2) Measurement of total amount of hydroxyl end groups in polycarbonate 30 mg of polycarbonate was weighed and dissolved in about 0.7 mL of deuterated chloroform, and this was put into an NMR tube having an inner diameter of 5 mm, and a ¹ H NMR spectrum was measured. The amount of total hydroxy end groups was quantified from the ratio of the intensity of signals based on the hydroxy end groups derived from each dihydroxy compound constituting the polycarbonate and the structural units derived from each dihydroxy compound. The equipment or conditions used are as follows.
Device: JNM-AL400 (resonance frequency 400 MHz) manufactured by JEOL Ltd.
-Measurement temperature: normal temperature-Relaxation time: 6 seconds-Number of integrations: 512 times The calculation method is as follows.

Analysis of ¹ H NMR in the case of the copolymer polycarbonate of BHEPF, ISB and PEG1000 exemplified in the present invention is performed as follows. Calculate the integrated value of the next peak.
(Α): 8.0-7.6 ppm: derived from all BHEPF structural units (proton number: 2, molecular weight: 464.51)
(Β): 5.6-4.8 ppm: derived from all ISB structural units (proton number: 3, molecular weight: 172.14)
(Γ): 3.7-3.5 ppm: derived from all PEG1000 structural units (proton number: 82.3, molecular weight: 1025.99)
(Δ): 2.8-1.0 ppm: derived from hydroxy end group (proton number: 1, molecular weight: 17.01)

  Hydroxy terminal group amount [ppm] = (δ) integral value × 17.01 / {(α} integral value / 2 × 464.51 + (β) /3×172.14+ (γ) /82.3×1025.99 } × 1000000

3) Reduced viscosity A methylene chloride was used as a solvent to prepare a polycarbonate solution having a concentration of 0.6 g / dL. Measured at a temperature of 20.0 ° C. ± 0.1 ° C. using an Ubbelohde viscometer manufactured by Moriyu Rika Kogyo Co., Ltd., and the relative viscosity η _rel is determined from the following equation from the solvent passage time t ₀ and the solution passage time t ,
η _rel = t / t ₀
From the relative viscosity, the specific viscosity ηsp was determined from the following formula.
η _sp = (η−η ₀ ) / η ₀ = η _rel −1
The reduced viscosity η _sp / C was determined by dividing the specific viscosity by the concentration C (g / dL). The higher this value, the higher the molecular weight.

4) 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.

5) Quantitative determination of foreign matter in polycarbonate resin The barrel set temperature of a 20 mm diameter single screw extruder equipped with a T die was set to 220 ° C, 230 ° C, 240 ° C, 240 ° C, 230 ° C from the pellet supply side, and the cooling roll was A film having a thickness of 30 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. Polycarbonate pellets were sampled every 3 hours during a 24-hour operation, and an average value measured 8 times was used.

6) Measurement of the amount of sulfur element in the polycarbonate resin A sample of the polycarbonate resin is collected in a platinum boat and heated in a quartz tube tubular furnace (AQF-100 type manufactured by Mitsubishi Chemical Corporation) to reduce the sulfur content in the combustion gas to 0. Absorbed with 0.03% aqueous hydrogen peroxide. SO ₄ ²⁻ in the absorbing solution was measured by an ion chromatograph (ICS-1000 type manufactured by Dionex).

7) Phase difference and wavelength dispersion of phase difference 4.0 g of polycarbonate resin sample vacuum-dried at 80 ° C. for 5 hours was heated by a hot press using a spacer having a width of 8 cm, a length of 8 cm and a thickness of 0.5 mm. After pressurizing for 1 minute at a press temperature of 250 ° C. under preheating for 1 minute and a pressure of 20 MPa, the spacers are taken out, and cooled with a water tube cooling press for 3 minutes at a pressure of 20 MPa to produce a film, width 6 cm, length A 6 cm sample was cut out.

  The sample was stretched with a batch-type biaxial stretching apparatus [manufactured by Toyo Seiki Sangyo Co., Ltd.] with a stretching temperature of glass transition temperature of polycarbonate resin + 15 ° C. and a stretching speed of 720 mm / min (strain rate of 1200% / min). Uniaxial stretching was performed at a magnification of 2.0. At this time, it extended | stretched in the perpendicular | vertical direction with respect to the extending | stretching state in the hold | maintained state (drawing ratio 1.0).

  Cut out to 4 cm in width and 4 cm in length from the stretched sample, and measure the phase difference at a measurement wavelength of 450, 500, 550, 590, and 630 nm using a phase difference measuring device [KOBRA-WPR manufactured by Oji Scientific Instruments Co., Ltd.] The wavelength dispersion was measured. For the wavelength dispersion, the ratio (Re450 / Re550) of the phase differences Re450 and Re550 measured at 450 nm and 550 nm was calculated. If the phase difference ratio is greater than 1, the chromatic dispersion is positive, and if it is less than 1, it is negative. It is shown that the smaller the ratio of the respective phase differences is less than 1, the stronger the negative wavelength dispersion.

8) Measurement of melt viscosity Measurement was performed with a capillary rheometer [manufactured by Toyo Seiki Co., Ltd.] using a sample dried in vacuum at 80 ° C for 5 hours. And heated to the same temperature as the reaction temperature, measured melt viscosity between shear rate 9.12～1824Sec ^-1, using a value of melt viscosity at 91.2sec ^-1. The sample at the outlet of the third vertical stirring reactor used an orifice with a die diameter of 1 mmφ × 40 mmL, and the sample at the outlet of the fourth horizontal stirring reactor used an orifice with a die diameter of 1 mmφ × 10 mmL.

[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, each reactor was previously set to the internal temperature and pressure according to reaction conditions as shown in Table-1.
Next, a specific molar ratio of BHEPF, ISB, PEG # 1000, and DPC (BHEPF / ISB / PEG # 1000 / DPC = 0.432 / 0.556 / 0. 0120 / 1.010) and heated to 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. And the liquid level was kept constant, controlling the opening degree of the valve | bulb (not shown) provided in the polymer discharge line of the tank bottom so that average residence time might be 90 minutes.

  Simultaneously with the start of the supply of the raw material mixed melt, a magnesium acetate aqueous solution as a catalyst was continuously supplied into the first vertical stirring reactor 6a from the catalyst supply port 1d at a ratio of 19 μmol with respect to 1 mol of all dihydroxy components.

  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. The actual operating conditions in these reactors are listed in Table-2.

  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 capacity of the fourth horizontal stirring reactor 6d was 250 L, the temperature of the heating medium was 240 ° C., and the reaction solution was supplied at a throughput of 40 kg / hr. The third vertical stirring reactor corresponds to the reactor immediately before the final polymerization reactor. That is, the internal temperature of the reactor immediately before the final polymerization reactor is 220 ° C.

  When the reaction conditions were adjusted so that the reduced viscosity at the outlet of the fourth horizontal stirring reactor 6d was in the range of 0.39 to 0.41, the pressure was 0.8 kPa and the average residence time was 100 minutes. The rotation speed of the stirring shaft was set to 1 rpm.

  The reaction liquid 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, Ltd .: biaxial extruder LABOTEX30HSS-32: L / D = 32] had two vent ports, and 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.

  A gear pump 4c is arranged on the resin discharge side of the extruder 16d, 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.

  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 polycarbonate, the reaction liquid corresponding to the outlet of the reactor immediately before the final polymerization reactor from the valve attached after the gear pump 4b is transferred from the valve attached after the gear pump 4c to the final polymerization reactor outlet. The corresponding reaction solution was sampled with polycarbonate pellets after the strand cutter 16b, and various analyzes were performed by the above-described analysis methods.

  When the operation was carried out for 24 hours under the above reaction conditions, the number of times that the strands were cut during 24 hours and the pelletization was stopped was twice. These results are summarized in Table 2.

[Example 2]
The pressure of the 3rd vertical stirring reactor 6c was 22 kPa, and the molecular weight and melt viscosity of the exit of the 3rd vertical stirring reactor 6c were reduced rather than Example 1. FIG. When the conditions of the fourth horizontal stirring reactor were adjusted so that the reduced viscosity at the outlet of the fourth horizontal stirring reactor 6d was in the range of 0.39 to 0.41 as in Example 1, the pressure was 0.6 kPa. The average residence time was 120 minutes. Items not mentioned were the same as in Example 1.

  Because the reaction time of the fourth horizontal stirring reactor, which is the highest temperature in the reactor, was longer, the color tone of the obtained polycarbonate was slightly worse than in Example 1, but the pelletization was stopped for 24 hours in the pelletizing step. The number of times was 1, which was good.

[Example 3]
The charge molar ratio of the raw materials was BHEPF / ISB / PEG # 1000 / DPC = 0.432 / 0.556 / 0.0120 / 0.995. When the conditions of the fourth horizontal stirring reactor 6d were adjusted in the same manner as in Example 1, the pressure was 1.5 kPa and the average residence time was 100 minutes. Items not mentioned were the same as in Example 1.

  Since the amount of hydroxy terminal and phenyl carbonate terminal was balanced, the rate of increase in molecular weight in the fourth horizontal reactor was increased, and the pressure was increased, so that the content of monohydroxy compound in the polycarbonate increased. The color tone was good.

[Example 4]
The same operation as in Example 1 was performed except that the stirring rotation speed of the fourth horizontal reactor 6d was changed to 6 rpm. The reaction liquid was entangled with the stirring shaft and it was difficult for the reaction liquid to sag to the outlet of the reactor, and the pelletization process was stopped 12 times during the 24-hour operation. The amount of foreign matter in the obtained polycarbonate pellets was significantly increased. The monohydroxy compound content was lower than in Example 1, and the color tone was good.

[Example 5]
The same operation as in Example 1 was performed except that the stirring rotation speed of the fourth horizontal stirring reactor 6d was changed to 0.5 rpm. Although the operation could be continued stably, compared with Example 1, the stirring efficiency was lowered, and therefore the phenol content in the obtained polycarbonate was increased. The amount of foreign matter has become very small. Moreover, the color tone of the pellet YI was also favorable.

[Example 6]
BHEPF, ISB, and DEG were used as the dihydroxy compound (Mole ratio: BHEPF / ISB / DEG / DPC / magnesium acetate = 0.349 / 0.495 / 0.156 / 1.005 / 1.50 × 10 ⁻⁵ ). The raw materials were continuously supplied to the reactor so that the throughput of the final polymerization reactor was 50 kg / hr. The reaction conditions were adjusted so that the reduced viscosity at the outlet of the fourth horizontal stirring reactor 6d was in the range of 0.41 to 0.44, and the conditions of each reactor were also adjusted appropriately according to the progress of the reaction. Unless otherwise specified, the same procedure as in Example 1 was performed.
A polycarbonate having a good color tone and a very small content of monohydroxy compound and no foreign matter in the polycarbonate were obtained.

[Example 7]
BHEPF and CHDM were used as the dihydroxy compound (feeding molar ratio: BHEPF / CHDM / DPC / magnesium acetate = 0.355 / 0.645 / 1.005 / 1.50 × 10 ⁻⁵ ). The raw materials were continuously supplied to the reactor so that the throughput of the final polymerization reactor was 50 kg / hr. The reaction conditions were adjusted so that the reduced viscosity at the outlet of the fourth horizontal stirring reactor 6d was in the range of 0.57 to 0.60, and the conditions of each reactor were also adjusted appropriately according to the progress of the reaction. Unless otherwise specified, the same procedure as in Example 1 was performed.
A polycarbonate having a good color tone and a very small content of monohydroxy compound and no foreign matter in the polycarbonate were obtained.

[Comparative Example 1]
The internal temperature of the third vertical stirring reactor 6c was raised to 230 ° C. When the conditions of the fourth horizontal stirring reactor were adjusted as in Example 1, the pressure was 1.1 kPa and the average residence time was 100 minutes. Items not mentioned were the same as in Example 1. Compared with Example 1, the obtained polycarbonate deteriorated in color and the monohydroxy compound content also increased.

[Comparative Example 2]
In Example 6, the internal temperature of the third vertical stirring reactor 6c was raised to 230 ° C. When the conditions of the fourth horizontal stirring reactor were adjusted in the same manner as in Example 6, the pressure was 0.9 kPa, and the average residence time was 100 minutes. Items not mentioned were the same as in Example 6. Compared with Example 6, the obtained polycarbonate deteriorated in color tone and the monohydroxy compound content also increased.

[Comparative Example 3]
In Example 7, the internal temperature of the third vertical stirring reactor 6c was raised to 230 ° C. When the conditions of the fourth horizontal stirring reactor were adjusted in the same manner as in Example 7, the pressure was 0.8 kPa and the average residence time was 100 minutes. Items not mentioned were the same as in Example 7. Compared with Example 7, the obtained polycarbonate deteriorated in color and the monohydroxy compound content also increased.

  The results of Examples 1 to 7 and Comparative Examples 1 to 3 are shown in Table 2, respectively.

[Summary]
As shown in Table 2, as specified in the production method of the present invention, by appropriately setting the reaction conditions of the reactor immediately before the final polymerization reactor, the quality of the polycarbonate can be improved and the operation can be improved. It has been found that there is an advantage that the yield is improved and the yield is improved. In particular, each of Examples 1 to 5 had a lower pellet YI than Comparative Example 1 and a good color tone. In addition, Examples 6 and 7 had lower pellet YI, better color tone than Comparative Examples 2 and 3, respectively, and the monohydroxy compound content was also low.

  Although the invention has been described in detail using specific embodiments, it will be apparent to those skilled in the art that various modifications and variations can be made without departing from the spirit and scope of the invention. This application is based on a Japanese patent application filed on March 31, 2011 (Japanese Patent Application No. 2011-080053), which is incorporated by reference in its entirety.

1a Raw material (carbonic acid diester) supply port 1b, 1c, 1d Raw material (dihydroxy compound) supply port 1e Catalyst supply port 2a Raw material mixing tank 3a Anchor type stirring blade 4a Raw material supply pump 4b, 4c, 4d Gear pump 5a Raw material filter 6a Type reaction vessel 6b second vertical reaction vessel 6c third vertical reaction vessel 6d fourth horizontal reactors 7a, 7b, 7c max blend blades 7d biaxial glasses type stirring blades 8a, 8b internal heat exchangers 9a, 9b reflux cooling 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 Meter 1 f product bag (paper bag, such as a flexible container bag)

Claims (16)

Dihydroxy compounds including the dihydroxy compound having a fluorene structure and a carbonic acid diester and a polymerization catalyst and fed continuously to the reactor, a method for producing a polycondensation match that polycarbonate,
A plurality of the reactors are connected in series at least;
The internal temperature of the reactor immediately before the final polymerization reactor is 200 ° C. or higher and lower than 225 ° C.,
The melt viscosity of the reaction solution at the outlet of the reactor immediately preceding the final polymerization reactor 20 Pa · s or more state, and are less 1000 Pa · s,
And method for producing a polycarbonate melt viscosity of the reaction solution at the outlet of the final polymerization reactor is characterized by the following der Rukoto 1800 Pa · s or more 5000 Pa · s. When the reduced viscosity of the reaction liquid at the outlet of the reactor immediately before the final polymerization reactor is P and the reduced viscosity of the reaction liquid at the outlet of the final polymerization reactor is Q, the following formula (2) is satisfied. The method for producing a polycarbonate according to claim 1.
1.5 ≦ Q / P ≦ 3.0 (2) 3. The polycarbonate production according to claim 1 or 2, wherein the final polymerization reactor is a horizontal stirring reactor having a plurality of horizontal rotation shafts therein, and the reaction conditions satisfy the following formula (3). Method.
500 ≤ ωμ ≤ 20000 (3)
[Ω: stirring blade rotation speed (rpm), μ: melt viscosity (Pa · s) of the reaction liquid at the outlet of the horizontal reactor] The method for producing a polycarbonate according to claim 3, wherein the reaction condition of the horizontal stirring reactor satisfies the following formula (4).
2 ≦ V / A ≦ 13 (4)
[V: Horizontal reactor volume (L), A: Reaction liquid throughput (kg / hr)] The method for producing a polycarbonate according to any one of claims 1 to 4 , wherein the temperature of the heating medium in the final polymerization reactor is 220 ° C or higher and 260 ° C or lower. First the molar ratio of the feed of carbonic acid diester with respect to all dihydroxy compounds used for the reaction in the charged into the reactor of a polycarbonate according to any one of claims 1 to 5 is 0.990 or more 1.030 or less Production method. The method for producing a polycarbonate according to any one of claims 1 to 6 , wherein the amount of all hydroxy end groups in the reaction solution at the outlet of the final polymerization reactor is 50 ppm or more and 1000 ppm or less. The amount of the monohydroxy compound in the reaction liquid at the outlet of the reactor immediately before the final polymerization reactor is 10 ppm or more and 3 wt% or less, and the monohydroxy compound in the reaction liquid at the outlet of the final polymerization reactor The method for producing a polycarbonate according to any one of claims 1 to 7 , wherein the amount is from 1 ppm to 1500 ppm. The method for producing a polycarbonate according to any one of claims 1 to 8 , wherein the pressure in the final polymerization reactor is 10 Pa or more and 2 kPa or less. The method for producing a polycarbonate according to any one of Claims 1 to 9 , 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 10 , wherein the dihydroxy compound having the fluorene structure is a compound represented by the following formula (1).

[In General Formula (1), R ^{1 to} R ⁴ are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted carbon group having 6 to 20 carbon atoms. It represents a cycloalkyl group or a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, and the same or different groups are arranged as each of the four substituents on each benzene ring. X is a substituted or unsubstituted alkylene group having 2 to 10 carbon atoms, a substituted or unsubstituted cycloalkylene group having 6 to 20 carbon atoms, or a substituted or unsubstituted carbon atom having 6 to 20 carbon atoms. Represents an arylene group. m and n are each independently an integer of 0 to 5. ] The dihydroxy compound containing the specific dihydroxy compound which has a site | part represented by following formula (5) in a part of structure other than the dihydroxy compound which has the fluorene site | part represented by said Formula (1) is used for reaction. 11. The method for producing a polycarbonate according to any one of 11 above.

[Except where moiety represented by the formula (5) is a portion constituting a part of the dihydroxy compound having when a portion constituting a part of -CH 2 _-OH, and the fluorene structure. ] The method for producing a polycarbonate according to any one of claims 1 to 12 , wherein the specific dihydroxy compound having a site represented by the formula (5) is a compound having a cyclic structure and an ether structure. The method for producing a polycarbonate according to claim 13 , wherein the specific dihydroxy compound having the bond structure of the formula (5) is a compound having a heterocyclic group represented by the following structural formula (6).

The method for producing a polycarbonate according to any one of claims 1 to 14 , comprising a step of supplying the polycarbonate obtained by polycondensation to a filter in a molten state without solidification and filtering. Polycarbonate obtained by polycondensation or, was filtered through the filter resin it is ejected from the die head in the form of a strand, cooled, any of claims 1 to 15 comprising the step of pelletizing with cutter A process for producing the polycarbonate according to claim 1.

Images