WO2012133856A1

WO2012133856A1 - Method for producing polycarbonate resin, polycarbonate resin pellets and stretched film

Info

Publication number: WO2012133856A1
Application number: PCT/JP2012/058748
Authority: WO
Inventors: 慎悟並木; 小田　康裕
Original assignee: 三菱化学株式会社
Priority date: 2011-03-31
Filing date: 2012-03-30
Publication date: 2012-10-04
Also published as: JP2012214803A; JP5857852B2

Abstract

The present invention pertains to a method for producing a polycarbonate resin by continuously feeding a carbonic acid diester and a dihydroxy compound containing a dihydroxy compound having a fluorene structure, with a polymerization catalyst, to reaction vessels, and conducting polycondensation. This method for producing a polycarbonate resin is characterized in that: the reaction vessels consists of at least a plurality of vessels connected in a series; the temperature inside the reaction vessel one before the last polymerization reaction vessel is 200°C to 225°C; and the melt viscosity of the reaction solution at the outlet of the reaction vessel one before the last polymerization reaction vessel is 20 Pa⋅s to 1000 Pa⋅s.

Description

Method for producing polycarbonate resin, polycarbonate resin pellet and stretched film

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

Polycarbonate resins generally contain bisphenols as monomer components and take advantage of transparency, heat resistance, mechanical strength, etc., so-called electrical / electronic parts, automotive parts, optical recording media, lenses, and other optical fields. Widely used as engineering plastic.

Recently, a copolymer polycarbonate resin derived from a dihydroxy compound having a fluorene structure in the side chain has been reported. Particularly, a copolymer polycarbonate resin with an aliphatic dihydroxy compound has excellent optical properties such as a small photoelastic coefficient. (Patent Documents 1 to 3).

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

When the copolymer polycarbonate resin using the dihydroxy compound having the above 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 dihydroxy compound and a carbonic acid diester such as diphenyl carbonate are transesterified in the presence of a polymerization catalyst at a high temperature of 200 ° C. or higher, and polymerization is advanced by removing by-product phenol out of the system to obtain a polycarbonate resin. It was.

However, a dihydroxy compound having a fluorene structure has poor heat stability, and particularly has a problem of coloring when a copolymerization reaction with a bisphenol compound or the aliphatic dihydroxy compound is performed. Among them, the aliphatic dihydroxy compound has a problem that the thermal stability is lower than that of bisphenols, and the resin is easily colored by thermal decomposition during the polycondensation reaction performed at a high temperature.

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. However, this method has been proposed (see Patent Documents 5 and 6), which is insufficient to satisfy the color tone and strength required for a stretched film.

Japanese Patent Laid-Open No. 10-101786 Japanese Laid-Open Patent Publication No. 2004-67990 Japanese Unexamined Patent Publication No. 2008-111047 International Publication No. 2006/41190 Japanese Unexamined Patent Publication No. 2009-161745 Japanese Unexamined Patent Publication No. 2007-70392

According to the study by the present inventors, when a polycarbonate resin 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, the molecular weight is increased in the reaction step. Especially when processed into a film and then stretched to produce a retardation film, if the molecular weight is low, it may cause stretch breakage, and stretching such as stretch ratio and stretch temperature to suppress stretch breakage. When the conditions are relaxed, there is a problem that a desired phase difference does not appear. On the other hand, in order to reduce the coloring of the resin, it is important to lower the reaction temperature as much as possible. When trying to achieve both of them, the problem is that the molten resin has a very high viscosity at the end of the reaction process. Became apparent.

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 polycarbonate resin is used for optical materials, the foreign matter becomes a fatal defect of the product, and the obtained polycarbonate resin is used for optical film applications such as retardation films, The product yield at the time of drawing or at the stage of assembling the members is also deteriorated.

Therefore, the present invention solves the above-described problems in the production of a polycarbonate resin using a dihydroxy compound having a fluorene structure, and produces a polycarbonate resin having excellent characteristics such as optical properties and mechanical properties with little coloring. The object is to produce a product with stable quality and high yield, and in particular, to solve the above problems even when an aliphatic dihydroxy compound having lower thermal stability than bisphenols is used in combination.

That is, the present invention is as follows.
1. A method for producing a polycarbonate resin 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 resin, the reactor comprising: At least a plurality of devices are connected in series, the internal temperature of the reactor immediately before the final polymerization reactor is 200 ° C. or more and less than 225 ° C., and the outlet of the reactor immediately before the final polymerization reactor The method for producing a polycarbonate resin, wherein the melt viscosity of the reaction solution in is from 20 Pa · s to 1000 Pa · s.
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 method for producing a polycarbonate resin according to item 1 above.
1.5 ≦ Q / P ≦ 3.0 (2)
3. 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]
4). 4. The method for producing a polycarbonate resin according to item 3 above, 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)]
5. 5. The method for producing a polycarbonate resin according to any one of 1 to 4 above, 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 resin 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. The production of the polycarbonate resin according to any one of the preceding items 1 to 6, wherein the molar ratio of the charged diester to the total dihydroxy compound used in the reaction when first charged into the reactor is 0.990 to 1.030. Method.
8). 8. The method for producing a polycarbonate resin 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 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 9. The method for producing a polycarbonate resin according to any one of 1 to 8 above, wherein the amount is 1 ppm or more and 1500 ppm or less.
10. 10. The method for producing a polycarbonate resin as described in 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 resin 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 resin according to any one of 1 to 11 above, wherein the dihydroxy compound having a fluorene structure is a compound represented by the following formula (1).

[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 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 group 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 resin according to any one of the above.

[However, the case where the site represented by the formula (5) is a site constituting a part of —CH ₂ —OH and the case where it is a site constituting a part of the dihydroxy compound having the fluorene structure are excluded. ]
14 14. The method for producing a polycarbonate resin 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 resin 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 resin according to any one of the preceding items 1 to 15, comprising a step of supplying a polycarbonate resin 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 resin obtained by polycondensation or a resin obtained by filtering the polycarbonate resin in the form of a strand from a die head, cooling, and then pelletizing with a cutter. A process for producing the polycarbonate resin according to claim 1.
18. 18. Polycarbonate resin pellets produced by the production method according to item 17 above.
19. 19. The polycarbonate resin pellet as described in 18 above, wherein a foreign matter 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 polycarbonate resin obtained by the production method according to any one of items 1 to 17 above.
21. 21. A stretched film obtained by stretching the transparent film according to item 20 in at least one direction.
22. 22. The stretched 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)
23. A stretched film made of a polycarbonate resin obtained 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 continuously polycondensing the film. A stretched film having in-plane birefringence at 590 nm of 0.0010 or more.
24. 24. The stretched film according to item 23, wherein the ratio of the retardation (Re450) measured at a wavelength of 450 nm to the retardation (Re550) measured at a wavelength of 550 nm satisfies the following formula (8).
0.80 ≦ Re450 / Re550 ≦ 0.95 (8)
25. 25. The stretched film according to item 23 or 24, wherein the thickness is 80 μm or less.
26. 26. The stretched film as described in any one of 23 to 25 above, wherein the reactor is connected at least in series, and the final polymerization reactor is a horizontal stirring reactor having a plurality of horizontal rotation shafts therein. .
27. In the final polymerization reactor, when the rotation speed of the stirring blade is ω (rpm) and the melt viscosity of the reaction liquid at the outlet of the reactor is μ (Pa · s), the preceding items 23 to 26 satisfying the following formula (3): The stretched film according to any one of 1.
500 ≤ ωμ ≤ 20000 (3)
28. 28. The stretched film as described in any one of 23 to 27 above, wherein the ω is less than 5 rpm.
29. 29. The stretched film according to any one of items 23 to 28, wherein the dihydroxy compound having a fluorene structure is a compound represented by the following formula (1).

[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 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 group having 6 to 20 carbon atoms. Represents an arylene group. m and n are each independently an integer of 0 to 5. ]
30. Any of 23 to 29 above, wherein a dihydroxy compound containing a specific dihydroxy compound having a site represented by the following formula (5) as a part of the structure in addition to the dihydroxy compound having a fluorene site represented by the formula (1) is used. 2. The stretched film according to 1.

[However, the case where the site represented by the formula (5) is a site constituting a part of —CH ₂ —OH and the case where it is a site constituting a part of the dihydroxy compound having the fluorene structure are excluded. ]
31. 31. The stretched film according to any one of items 23 to 30, wherein the specific dihydroxy compound having a site represented by the formula (5) is a compound having a cyclic structure and an ether structure.
32. 32. The stretched film according to any one of items 23 to 31, wherein the specific dihydroxy compound having a bond structure represented by the formula (5) is a compound having a heterocyclic group represented by the following structural formula (6).

33. 33. The stretched film according to any one of the items 23 to 32, wherein the polycarbonate resin has a glass transition temperature of 120 ° C. or higher and 150 ° C. or lower.
34. 34. The stretched film according to any one of items 23 to 33, wherein the reduced viscosity of the polycarbonate resin is 0.38 dL / g or more and 0.50 dL / g or less.
35. The polycarbonate resin is molded into an unstretched film having a thickness of 100 μm ± 10 μm, and stretched to break when subjected to a tensile test at a glass transition temperature of + 6 ° C. and a tensile speed of 625% / min. 35. The stretched film according to any one of items 23 to 34, wherein the degree (tensile elongation at break) is 220% or more.

By the polycarbonate resin production method of the present invention, it is possible not only to efficiently and stably produce a polycarbonate resin excellent in optical characteristics, hue, heat resistance, thermal stability and mechanical strength, but also to have a specific birefringence. It is possible to obtain a stretched film useful for applications such as a phase difference film having a thickness of. In particular, according to the method for producing a polycarbonate resin of the present invention, it is possible to produce a polycarbonate resin having a small amount of foreign matter and suitably used for optical applications such as a retardation film with a high yield.

FIG. 1 is an overall process diagram showing an example of a method for producing a polycarbonate resin 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 the present specification, when the expression “˜” is used, it is used in a sense including numerical values or physical values before and after that. Further, in this specification, “wt%” and “wt%” are synonymous, and when “ppm” is simply described, it means “wt ppm”.

The method for producing a polycarbonate resin of the present invention is a method for producing a polycarbonate resin 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. In addition, 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 is one of the final polymerization reactors. The melt viscosity of the reaction liquid at the outlet of the previous reactor is 20 Pa · s or more and 1000 Pa · s or less. Hereinafter, the production method of the polycarbonate resin of the present invention may be referred to as “the production method of the present invention”.

<Outline of polycarbonate resin 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 resin is produced by condensation.

In the following, the first reactor is referred to as the first reactor, the second reactor is referred to as the second reactor, the third reactor is referred to as the third reactor, respectively. The reactor is also called similarly.

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 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 resin.

In addition, the pressure in this specification refers to what is called an absolute pressure expressed on the basis of a 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 through 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, since the unreacted dihydroxy compound tends to generate a colored product by thermal decomposition, the temperature of the heating medium in the reactor before the final polymerization reactor is preferably less than 230 ° C. The lower limit of the temperature of the heating medium is not particularly limited as long as the reaction temperature can be maintained.

Any known reactor may be used in the present invention. 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. By continuously producing using a horizontal stirring reactor, it becomes possible to efficiently produce a polycarbonate resin having a stable molecular weight and composition, and the orientation when producing a stretched film becomes uniform. A stretched film having a stable retardation can be obtained.

After the polycondensation step, the obtained polycarbonate resin 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 resin, a step of adding a heat stabilizer, a release agent, or the like may be appropriately added.

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 step of the manufacturing method according to the manufacturing method of the present invention will be described. The production method of the present invention comprises a dihydroxy compound containing a dihydroxy compound having a fluorene structure (fluorene-based dihydroxy compound) 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 above reaction, since a monohydroxy compound is by-produced, the monohydroxy compound is removed from the reaction system to advance the reaction and produce a polycarbonate resin. When DPC is used as the carbonic acid diester, the monohydroxy compound becomes phenol, and the reaction proceeds by removing the phenol under reduced pressure.

<Raw material preparation process>
The dihydroxy compound including the fluorene-based dihydroxy compound used as a raw material for the polycarbonate resin and the carbonic acid diester are a batch type, semi-batch type or continuous type stirring tank type apparatus in an atmosphere of an inert gas such as nitrogen or argon. Use to prepare as raw material mixed melt or drop them independently into the reactor.

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.

Further, an antioxidant may be added to the raw material mixed 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.

A specific example 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 being melted, 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 to 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 increases, and the quality of the resin may be deteriorated. On the other hand, if the temperature is too low, the reaction rate is lowered, and thus productivity may be lowered.

Since the melt polycondensation reaction used in the present invention is an equilibrium reaction, the reaction is promoted by removing the by-product monohydroxy compound from the reaction system, and therefore it is preferable to use a reduced pressure. 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 resin. 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 further 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 resin.

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, from the viewpoint of the color tone of the polycarbonate resin, regardless of the former stage and the latter stage, the parts constituting the reaction apparatus, the parts contacting the raw material monomer or the polymerization liquid of the components such as piping (hereinafter referred to as “wetted part”) The surface material of the stainless steel, glass, nickel, tantalum, chromium and Teflon (registered trademark) having a nickel content of 10% by weight or more in a ratio of at least 90% of the total surface area of the wetted part. It is preferably composed of one 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.), Sunmeler 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 rotation shafts are preferably arranged so as to have self-cleaning properties.

As the type of the stirring blade, for example, a uniaxial stirring blade such as a disk type and a paddle type, 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 stirring blades are installed in at least two or more stages per rotating shaft, and the reaction solution is scraped up or spread by the stirring blades to update the surface of the reaction solution. Further, when the length of the horizontal rotation axis of the horizontal reactor is L and the rotation diameter of the stirring blade is D, L / D is preferably 1 to 15, more preferably 2 to 14.

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

The polycarbonate resin produced in the present invention also increases the viscosity of the reaction solution as the reaction proceeds, as in the case of ordinary polycarbonate resins. Therefore, in each multi-tank reactor, the by-product is produced as the polycondensation reaction proceeds. In order to more effectively remove the monohydroxy compound (which becomes phenol when DPC is used) out of the system and to ensure the fluidity of the reaction solution, the reaction conditions are increased stepwise. It is preferable to set a higher temperature and a higher vacuum.

In order to prevent quality deterioration such as color tone of the obtained polycarbonate resin, 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 to the outlet of the reactor, bubbles are trapped in the reaction liquid, and in the pelletization process, the strands containing the bubbles are 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 obtained polycarbonate resin, since it is necessary to minimize the residence time in the final polymerization reactor where the reaction temperature becomes the highest, the reaction liquid charged into the final polymerization reactor Is preferably as low as possible and has 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 liquid 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 of the obtained polycarbonate resin 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 means a melt viscosity at a shear rate of 91.2 s ⁻¹ measured at a temperature equal to the temperature of 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 it 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)

When Q / P is 3.0 or less, it is possible to suppress an excessive heat history in the final polymerization reactor and to prevent the color tone of the resulting resin from deteriorating. Therefore, Q / P is preferably 2.5 or less, more preferably 2.2 or less, and particularly preferably 2.0 or less. Further, by setting Q / P to 1.5 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. Therefore, Q / P is preferably 1.6 or more, more preferably 1.7 or more, and particularly preferably 1.8 or more.

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 normal polycarbonate resin 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 (resin production volume) to control the appropriate residence time. To do. 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 resin using a fluorene-based dihydroxy compound used in the present invention, the liquid volume is more easily decomposed than bisphenols used in a normal polycarbonate resin, so that the liquid volume is more severely adjusted.

For this reason, the final polymerization reactor in the present invention preferably satisfies the 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 13 or less, it is possible to prevent the capacity of the reactor from becoming excessive with respect to the amount of the reaction solution, and to reduce the amount of solution in the reactor when shortening the residence time. It is possible to suppress the reaction liquid from flowing into the outlet of the reactor and improve the pelletization yield. 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 2 or more, the residence time will not be too short, 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 the polycarbonate resin of the present invention is produced using a substituted diphenyl carbonate such as diphenyl carbonate or ditolyl carbonate as the carbonic acid diester, phenol or substituted phenol as a monohydroxy compound is by-produced, and the polycarbonate resin It is inevitable that it remains.

However, monohydroxy compounds such as phenol and substituted phenol may cause odor during molding. The polycarbonate resin obtained by a normal batch reaction, not the continuous type as in the present invention, contains a monohydroxy compound having an aromatic ring such as by-product phenol of 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 remaining 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 to distill it off. However, the aliphatic polycarbonate resin using the fluorene 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 resin using bisphenol A as a monomer. In addition, the molecular weight increase rate in the latter 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 terminal, the more effective the thermal stability of the resulting polycarbonate resin, such as the reduction in coloration when the resin is melted and retained.

The balance of such end groups can be controlled by the molar ratio of the total dihydroxy compound used in the reaction and the carbonic acid diester when charged to the first reactor. On the other hand, the molar ratio of the carbonic acid diester is preferably 0.990 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 1.025 or less.

By making the molar ratio of 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 reached. 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 becomes 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, the polycarbonate resin obtained by polycondensation of the dihydroxy compound containing the dihydroxy compound having the fluorene structure according to the present invention is lower in thermal stability than the conventional aromatic polycarbonate resin, so that the reaction temperature is as low as possible. Although it is necessary to set low, the viscosity of a reaction liquid becomes higher than the conventional polycarbonate resin for that purpose.

When the viscosity of the reaction liquid increases, the reaction liquid 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]

It should be noted that the above condition does not depend on the shaft diameter of the stirring blade, so it does not relate 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 20000 or less, it is possible to suppress the reaction liquid from being wound around the stirring shaft, to improve the yield in the pelletizing step, and to prevent an increase in foreign matters 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 resin obtained by polycondensation according to the present invention may be subjected to the polycondensation reaction described above, and then passed through a filter in a molten state to filter foreign matters. 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, and 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 resin obtained by polycondensation as described above, usually the hue or heat stability, and further, the secondary monomer in the transesterification reaction, which may adversely affect the product due to bleed out, etc. The resulting monohydroxy compound or low molecular weight compound such as polycarbonate resin oligomer remains, but these are reduced 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 devolatilize and remove. 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, it is preferable to filter with a filter in order to remove foreign matters such as burns or gel in the polycarbonate resin obtained by polycondensation. 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 disc 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 nonwoven fabric type can be used in addition to a regular weaving portion of the foreign matter, 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 opening of the filter is preferably 50 μm or less, more preferably 40 μm or less, still more preferably 20 μm or less, and 10 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. To tell.
βχ = (number of particles on the primary side larger than χμm) / (number of particles on the secondary side larger than χμm) …… (9)
(Here, the primary side means before filtration with a filter, and the secondary side means 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 passivated surface, and roasted (heated) 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 treatment temperature is preferably 5 to 100 ° C. More preferably, it is 50 ° C. to 90 ° C., and the treatment time is preferably 5 minutes to 120 minutes, more preferably 10 minutes to 60 minutes.

If the concentration of nitric acid is too low, the processing temperature is too low, or the processing time is too short, the formation of passives will be insufficient, the concentration of nitric acid will be too high, the processing temperature will be too high, or the processing time will be If it is too long, the filter media will be severely damaged and the required filtration accuracy may not be achieved.

The material of the containment vessel of the filter used in the 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 resin from staying in the filter storage container and prevent deterioration of the polycarbonate resin, it is preferable that the polycarbonate resin supply port is disposed at the bottom of the filter storage container and the discharge port is disposed at the top. .

Furthermore, in the 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, when stranding or pelletizing the polycarbonate resin directly in contact with the outside air, it is preferably class 7 as defined in JIS B 9920 (2002), more preferably, in order to prevent foreign matter from being mixed from the outside air. It is preferable to carry out in a clean room with higher cleanliness than class 6.

The polycarbonate resin filtered by the filter is cooled and solidified and pelletized by a rotary cutter or the like, and it is preferable to use a cooling method such as air cooling or water cooling when pelletizing. 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 in terms of 99% removal filtration accuracy.

<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.

The filter medium constituting the raw material filter may be any one of metal wind, laminated metal mesh, metal nonwoven fabric, porous metal plate, and the like. 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. If the raw material is too high, there is a problem such as thermal decomposition. The temperature is preferably 200 ° C, more preferably 100 ° C to 150 ° C.

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

<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 resin 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 condensation 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, a step of devolatilizing and removing unreacted raw materials or reaction by-products in the polymerization reaction solution, a step of adding a heat stabilizer, a release agent, a colorant, or the like, or a polycarbonate resin with pellets having a predetermined particle size Through the step of forming, a pellet of polycarbonate resin is 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 that the high temperature, high vacuum, and low stirring speed are achieved 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. A gear pump 4b is provided after the third vertical stirring reactor 6c because the transferred reaction liquid has a high viscosity.

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.

In addition, distilling

tubes

11a, 11b, 11c, and 11d for discharging by-products generated by the polycondensation reaction are attached to these four reactors, respectively. 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, a cold trap (not shown) is provided downstream of the

condensers

12c and 12d attached to the third vertical stirring reactor 6c and the fourth horizontal stirring reactor 6d, respectively, so that by-products are continuously present. Solidified and recovered.

The reaction liquid raised to a predetermined molecular weight is extracted from the fourth horizontal stirring reactor 6d and transferred to the twin screw extruder 15a by the gear pump 4c. The twin screw extruder is equipped with a vacuum vent to remove residual low molecular components in the polycarbonate resin. Further, an antioxidant, a light stabilizer, a colorant, a release agent, 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 solution is kept constant so as to have a predetermined average residence time. As a method of keeping the liquid level in the first vertical stirring 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 fourth horizontal stirring reactor 6d, and under temperature and pressure conditions suitable for performing the latter reaction as described later, The by-produced phenol and partially unreacted monomer are removed out of the system through the distillation pipe 11d to produce a polycarbonate resin. 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 fourth horizontal stirring reactor 6d has one or more horizontal rotation shafts, and extends from the horizontal rotation shaft in the vertical direction, a disk shape, a wheel shape, a saddle shape, a rod shape, or a window frame shape. One or two or more kinds of stirring blades such as those described above are combined, and at least two stages are installed in the horizontal direction per rotation axis.

When there are two or more horizontal rotation shafts, the stirring blades provided on each horizontal rotation shaft are arranged to have self-cleaning properties. It is easy to stably obtain a polycarbonate resin having a reduced viscosity suitable for a stretched film by renewing the surface of the reaction solution by rolling up or spreading the reaction solution with such a stirring blade.

The shape is such that L / D is 1 to 15 when the length of the horizontal rotation shaft is L and the rotation diameter of the stirring blade is D. 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.

Examples of a stirrer having a biaxial glasses-type stirring blade 7d as the fourth horizontal stirring reactor 6d are 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 the fourth horizontal stirring reactor 6d having a larger hold-up than the twin-screw vent type extruder in terms of the device structure. In addition, by suppressing shearing heat generation, the temperature can be lowered, and it becomes possible to obtain a polycarbonate resin with improved color tone and excellent mechanical properties.

The horizontal stirring reactor is a device 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 numerical values, the raw material mixed melt and the catalyst are continuously supplied to perform the transesterification reaction. Based melt polycondensation is started.

Thereby, the average residence time of the polymerization reaction liquid in each reactor becomes equal to that in the steady operation immediately after the start of the melt polycondensation. As a result, the polymerization reaction liquid does not receive an excessive heat history, and foreign matters such as gel or burns generated in the obtained polycarbonate resin are reduced. Also, the color tone is good.

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

(Dihydroxy compound)
The dihydroxy compound used for the production of the polycarbonate resin of the present invention 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 resin, 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 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 group 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 a hydrogen atom or an unsubstituted or ester group, an ether group, a carboxylic acid, an amide group, or a halogen substituted alkyl group having 1 to 6 carbon atoms, preferably a hydrogen atom or a carbon number More preferred are 1 to 6 alkyl groups. 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. A cycloalkylene group having 6 to 20 carbon atoms, an unsubstituted or ester group, an ether group, a carboxylic acid, an amide group, or an arylene group having 6 to 20 carbon atoms substituted with halogen is preferable. More preferably, it is an alkylene group of ˜6. M and n are each independently preferably an integer of 0 to 2, with 0 or 1 being particularly 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-hydroxy-3-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] fluorene, 9,9-bis [4- (2-hydroxyethoxy) -3-cyclohexylphenyl] fluorene, 9,9-bis [4- (2 -Hydroxyethoxy) -3-phenylphenyl] fluorene, 9,9-bis [4- (2-hydroxyethoxy) -3,5-dimethylphenyl] fluorene, 9,9-bis [4- (2-hydroxyethoxy) -3-tert-butyl-6-methylphenyl] fluorene and 9,9-bis [4- (3-hydroxy-2,2-dimethylpropoxy) phenyl] fluorene.

Among these, 9,9-bis (4-hydroxy-3-methylphenyl) fluorene, 9,9-bis [4- (2) is preferable from the viewpoint of optical performance, handling, availability, and the like. -Hydroxyethoxy) phenyl] fluorene, 9,9-bis [4- (2-hydroxyethoxy) -3-methylphenyl] fluorene, particularly preferably 9,9-bis [4- (2-hydroxyethoxy) Phenyl] fluorene.

The polycarbonate resin of the present invention is preferably obtained by using 18 mol% or more of a fluorene-based dihydroxy compound having a structural unit represented by the above general formula (1) as a raw material monomer, based on the total dihydroxy compound, More preferably, it is 20 mol% or more, Most preferably, it is 25 mol% or more. Moreover, it is preferably 90 mol% or less, more preferably 70 mol% or less, and particularly preferably 50 mol% or less.

If the amount of the monomer having the structural unit is too small or too large, the obtained polycarbonate resin may not exhibit the desired optical performance. If the amount is too large, the melt viscosity of the obtained polycarbonate resin becomes excessively high, and it may not be able to be stably discharged due to wrapping around the stirring blade of the horizontal stirring reactor. May cause deterioration of the polycarbonate resin. Moreover, the fluidity | liquidity at the time of shape | molding to a film etc. falls, and there exists a tendency to reduce productivity or a moldability.

The polycarbonate resin of the present invention preferably contains a structural unit derived from a dihydroxy compound other than the fluorene-based dihydroxy compound in order to adjust the desired optical properties. Among these, from the viewpoint of optical properties such as moderate birefringence or low photoelastic coefficient, heat resistance or mechanical strength, a dihydroxy compound (specific dihydroxy compound) having a portion represented by the above formula (5) in a part of the structure is provided. 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, etc. Can be mentioned.

Examples of the dihydroxy compound having the cyclic ether structure include a dihydroxy compound represented by the following formula (10) and a spiro glycol 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 are in 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 preferred from the viewpoints of availability, handling, reactivity during polymerization, and hue of the obtained polycarbonate resin. A representative dihydroxy compound having a cyclic ether structure is preferable, and a dihydroxy compound represented by the above formula (10) or a dihydroxy compound having two cyclic ether structures such as spiroglycol represented by the following formula (11) is further included. Preferably, an anhydrous sugar 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, dihydroxy compounds having no aromatic ring structure are preferably used from the viewpoint of optical properties of the polycarbonate resin. 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.

Among them, when the dihydroxy compound represented by the above formula (10), (11) or (12) is used as a raw material monomer, it is preferably used in an amount of 10 mol% or more, more preferably 30 mol% or more, especially with respect to the total dihydroxy compound. Preferably it is 40 mol% or more. The upper limit is preferably 80 mol% or less, more preferably 60 mol% or less, and particularly preferably 50 mol% or less. If the amount of the dihydroxy compound used is too small or too large, the obtained polycarbonate resin may not exhibit the desired optical performance.

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

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, and 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, triethylphenyl Basic ammonium compounds such as ammonium 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- Amine compounds such as toxipyridine, 4-methoxypyridine, 2-dimethylaminoimidazole, 2-methoxyimidazole, imidazole, 2-mercaptoimidazole, 2-methylimidazole and aminoquinoline, and di- (tert-butyl) amine; And 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, more preferably 0.001% by weight to 0.1% by weight, based on 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 a polycarbonate resin is produced using isosorbide containing these decomposed products, the resulting polycarbonate resin is not only colored but significantly deteriorated in physical properties, and also affects the polymerization reaction, resulting in a high molecular weight polymer. May not be obtained, which is not preferable.

The polycarbonate resin 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, And dihydroxy compounds derived from terpene compounds such as 3-adamantanedimethanol 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-hydroxy) Enyl) cyclohexane, bis (4-hydroxyphenyl) sulfone, 2,4′-dihydroxydiphenylsulfone, bis (4-hydroxyphenyl) sulfide, 4,4′-dihydroxydiphenyl ether and 4,4′-dihydroxy-3,3 ′ -Dichlorodiphenyl ether and the like.

These other dihydroxy compounds may be used alone or in combination with the specific dihydroxy compound depending on the required performance of the polycarbonate resin to be obtained, and after combining two or more kinds, the fluorene-based dihydroxy compound or the specific dihydroxy compound. You may use together with a compound. Above all, in order to obtain the desired optical performance, to stabilize production, and to obtain a polycarbonate resin having characteristics suitable for a stretched film, two or more kinds of dihydroxy compounds are copolymerized in addition to the fluorene-based dihydroxy compound. Is preferred.

Among these, from the viewpoint of the optical properties of the polycarbonate resin, a dihydroxy compound having no aromatic ring structure in the molecular structure, that is, an aliphatic hydrocarbon dihydroxy compound or an alicyclic hydrocarbon dihydroxy compound is preferable. May be.

Among the above, the aliphatic hydrocarbon dihydroxy compounds suitable for the polycarbonate resin of the present invention include 1,3-propanediol, 1,4-butanediol, 1,5-heptanediol, and 1,6-hexanediol. 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 resin 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.

Examples of the carbonic acid diester used usually include those represented by the following formula (13). 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 carbonate 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 resin. It is preferable to use what was done.

(Transesterification reaction catalyst)
The polycarbonate resin 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 performed in the presence of a transesterification reaction catalyst. The transesterification reaction catalyst (hereinafter simply referred to as a catalyst or a polymerization catalyst) that can be used in the production of the polycarbonate resin of the present invention may be used. ) Can greatly affect the reaction rate or the color tone of the polycarbonate resin obtained by polycondensation.

The catalyst used is not limited as long as it can satisfy the transparency, hue, heat resistance, thermal stability, and mechanical strength of the produced polycarbonate resin. 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 borohydride, potassium phenyl boronate, lithium phenyl boronide, cesium phenyl borohydride, sodium benzoate, potassium benzoate, lithium benzoate, cesium benzoate, hydrogen phosphate Sodium, 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. Among these, lithium compounds are preferable from the viewpoint of polymerization activity and the hue of the obtained polycarbonate resin.

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 polycarbonate resin obtained.

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 Hydroxide and butyltriphenyl 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 generally 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 or less is preferable, More preferably, it is 30 micromol or less, More preferably, it is 20 micromol or less.

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 that the following formula (14) is satisfied.

0.1 ≤ B / A ≤ 2 (14)

If the amount of the catalyst is too small, the polymerization rate is slowed down. Therefore, in order to obtain a polycarbonate resin having a desired molecular weight, the polymerization temperature must be increased by that much. Therefore, there is a high possibility that the hue of the resulting polycarbonate resin 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. There is.

On the other hand, if the amount of the polymerization catalyst used is too large, undesirable side reactions may occur, and the hue of the resulting polycarbonate resin may be deteriorated or the resin may be colored during molding.

Among the Group 1 metals, sodium, potassium, and cesium may adversely affect the hue if they are contained in a large amount in the polycarbonate resin. And these metals may mix not only from the catalyst to be used but from a raw material or a reaction apparatus.

Regardless of the source, the total amount of the compound of the metal in the polycarbonate resin is preferably 2 μmol or less, more preferably 1 μmol or less, still more preferably 0.5 μmol or less, per 1 mol of the total dihydroxy compound as the metal amount.

<Physical properties and applications of polycarbonate resin>
The molecular weight of the polycarbonate resin 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. Preferably, it is 0.35 dL / g or more, more preferably 0.40 or more. On the other hand, it is preferably 1.20 dL / g or less, more preferably 0.80 dL / g or less, further preferably 0.60 dL / g or less, and 0.50 dL / g or less. Particularly preferred, most preferred is 0.45 dL / g or less.

If the reduced viscosity of the polycarbonate resin is too low, the mechanical strength of the molded product will be low, which may cause breakage when processed into a stretched film. If it is reduced, the birefringence required for the retardation film may not be obtained. On the other hand, if the reduced viscosity is too large, it may not be possible to wrap around the stirring blade of the horizontal stirring reactor and prevent stable discharge, but also the fluidity when forming into a film or the like will be reduced, and the productivity will be reduced. Or there exists a tendency to reduce a moldability. The reduced viscosity is a value measured using an Ubbelohde viscometer at a temperature of 20.0 ° C. ± 0.1 ° C., prepared precisely using a methylene chloride as a solvent and a polycarbonate resin concentration of 0.6 g / dL. It is.

The glass transition temperature of the polycarbonate resin in the present invention is preferably 100 ° C. or higher, more preferably 110 ° C. or higher, still more preferably 120 ° C. or higher, and particularly preferably 125 ° C. or higher. If the glass transition temperature is excessively low, after the polycarbonate resin of the present invention is formed into a film, it tends to deteriorate the heat resistance when stretched into a retardation film, etc. There is a possibility that the phase difference changes with time. On the other hand, the glass transition temperature is preferably 160 ° C. or less, more preferably 150 ° C. or less, still more preferably 140 ° C. or less, and particularly preferably 135 ° C. or less.

If the glass transition temperature is excessively high, the melt viscosity during the production of the polycarbonate resin becomes high, and there is a possibility that it will not be able to be discharged stably by wrapping around the stirring blade of the horizontal stirring reactor. As a result, it tends to be difficult to increase the molecular weight (reduced viscosity) which greatly affects the fracture at the time of stretching. Furthermore, when molding into a film, the molding stability may be deteriorated, such as uneven thickness. If the molding temperature is set high in order to suppress this, the resin will be deteriorated and the film may be stretched or machined. Strength may be reduced.

According to the production method of the present invention, a resin with little coloring and less foreign matter can be obtained while being a polycarbonate resin 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.

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 preferable 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 of the polycarbonate resin, Tg, melt flow characteristics, etc., 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 (unstretched 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.

The 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, methyl ethyl ketone and the like are 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.

The thickness of the unstretched film is preferably in the range of 20 μm to 400 μm, more preferably 30 μm to 300 μm, still more preferably 50 μm to 200 μm, and particularly preferably 80 μm to 150 μm. 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.

The polycarbonate resin of the present invention was molded into an unstretched film having a thickness of 100 μm ± 10 μm, and the elongation (tension) until breaking when a tensile test was conducted at a glass transition temperature of + 6 ° C. and a tensile speed of 625% / min. (Elongation at break) is preferably 120% or more, more preferably 150% or more, still more preferably 200% or more, and particularly preferably 220% or more.

The higher the tensile elongation at break, the more the fracture during stretching is suppressed.In general, the greater the elongation at break, the smaller the stress during stretching and the weaker the retardation, so the upper limit is Usually, it is 400% or less, preferably 300% or less.

Polycarbonate resins made from dihydroxy compounds having a fluorene structure have a rigid fluorene structure, so if the molecular structure is copolymerized with a flexible dihydroxy compound or the molecular weight is increased, the tensile elongation at break tends to increase. However, if the dihydroxy compound having a fluorene structure is excessively reduced, the desired optical performance will not be exhibited, and attempts to increase the reduced viscosity may lead to degradation of the polycarbonate resin and manufacturing problems as described above. It is not easy to satisfy all of the plurality of performances.

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. If the stretching temperature is excessively low, the film may be broken at the time of stretching, and if it is excessively high, the birefringence of the stretched film may be reduced and a desired phase difference may not be obtained.

The draw ratio is determined by the target retardation value, but is preferably 1.05 to 4 times, more preferably 1.1 to 3 times, still more preferably 1.5 to 2.5 times. It is. The stretching direction may be the longitudinal direction (longitudinal stretching) of the unstretched film, or may be the perpendicular direction (lateral stretching).

The birefringence when the film formed by molding the polycarbonate resin in the present invention is stretched is usually 0.0010 or more, preferably 0.0014 or more, more preferably 0.0016 or more, still more preferably 0.0018 or more, Particularly preferred is 0.0020. 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, if the birefringence is excessively increased, it is necessary to set the stretching ratio high and the stretching temperature low, and orientation relaxation after stretching tends to occur, and the change in phase difference may increase. Usually, it is 0.0060 or less, preferably 0.0050 or less, more preferably 0.0040 or less, and particularly preferably 0.0035 or less.

The thickness of the stretched film according to the present invention is preferably in the range of 10 μm to 200 μm, more preferably 20 μm to 150 μm, still more preferably 30 μm to 100 μm, and particularly preferably 40 μm to 80 μm. When the stretched film is excessively thick, the thickness when assembled as a retardation plate is increased, and a display having a desired thickness cannot be obtained. On the other hand, if it is too small, it may cause breakage during stretching or assembly.

The retardation of the stretched film (retardation film) according to the present invention is represented by the product of in-plane birefringence and the film thickness, and is usually 30 nm to 400 nm as a value when measured at a measurement wavelength of 590 nm. The thickness is preferably 50 nm to 300 nm, particularly preferably 100 nm to 200 nm. If the retardation is excessively small, the performance as a retardation film tends to be inferior. If the retardation is excessively large, it is necessary to increase the thickness of the film, so that the retardation plate cannot be reduced in weight and size.

The stretched film (retardation film) according to the present invention is laminated and bonded via a known iodine-based or dye-based polarizing plate and an adhesive, thereby being used for various liquid crystal display devices or organic EL display devices. It can be used as a phase difference plate.

In the stretched film according to the present invention, the ratio (Re450 / Re550) 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. 0.70 or more and 1.0 or less is more preferable, 0.80 or more and 0.95 or less is further preferable, and 0.85 or more and 0.93 or less is particularly preferable.

If the ratio is within the above range, ideal phase difference characteristics 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 a decrease in contrast may 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 stretched film of the present invention is used as a retardation film 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), and reflection of external light. It can be used for prevention, color compensation, or conversion of linearly polarized light into circularly polarized light. Especially, it can use suitably in the organic electroluminescence display which plays the role of a reflecting plate with a back electrode being a metal.

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. .

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

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

The polycarbonate resin according to the present invention is excellent in heat resistance and moldability, and further has little transparency and high transparency. Therefore, it can be used for other optical films, optical discs, optical prisms, pickup lenses, and the like.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples unless it exceeds the gist. 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 and physical property evaluation of the polycarbonate resin were performed by the following methods 1) to 8).

1) Content of monohydroxy compound (phenol) in the reaction solution About 0.5 g of a sample was precisely weighed and dissolved in 5 mL of methylene chloride, and then acetone was added so that the total amount was 25 mL. The solution was filtered through a 0.2 μm disk filter, and the amount of phenol was determined by liquid chromatography, and then the content was calculated. The equipment 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
Analysis 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 hydroxy terminal group amount in polycarbonate resin 30 mg of polycarbonate resin was weighed and dissolved in about 0.7 mL of deuterated chloroform, and this was put in an NMR tube having an inner diameter of 5 mm, and ¹ H NMR spectrum was measured. The amount of total hydroxy end groups was quantified from the ratio of signal strength based on the hydroxy end groups derived from each dihydroxy compound constituting the polycarbonate resin and the structural units derived from each dihydroxy compound. The equipment or conditions used are as follows.
・ Equipment: JNM-AL400 manufactured by JEOL Ltd. (resonance frequency 400 MHz)
-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 resin of BHEPF, ISB and PEG # 1000 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 PEG # 1000 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 resin 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 obtained from the following equation from the passage time t _{0 of the} solvent and the passage time t of the solution. ,
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) Glass transition temperature (Tg)
Using a differential scanning calorimeter (DSC220, manufactured by SII Nanotechnology Inc.), about 10 mg of polycarbonate resin was heated at a temperature increase rate of 20 ° C./min, and measured according to JIS-K7121 (1987). Extrapolated glass transition start temperature, which is the temperature at the intersection of the straight line that extends the low-temperature base line to the high-temperature side and the tangent line drawn at the point where the slope of the step change portion of the glass transition is maximized Was determined as the glass transition temperature.

5) Pellets YI value of polycarbonate resin The hue of the polycarbonate resin was evaluated by measuring the YI value (yellow index value) in the reflected light of the pellet according to ASTM D1925. As the apparatus, a spectrocolorimeter CM-5 manufactured by Konica Minolta Co., Ltd. was used, and a measurement diameter of 30 mm and SCE were selected as measurement conditions. A petri dish calibration glass CM-A212 was fitted into the measurement part, and a zero calibration box CM-A124 was placed thereon to perform zero calibration, followed by white calibration using a built-in white calibration plate.

Measure using white calibration plate CM-A210, L * is 99.40 ± 0.05, a * is 0.03 ± 0.01, b * is −0.43 ± 0.01, YI is − It was confirmed to be 0.58 ± 0.01. The pellets were measured by packing them into a cylindrical glass container having an inner diameter of 30 mm and a height of 50 mm to a depth of about 40 mm. The operation of taking out the pellet from the glass container and then performing the measurement again was repeated twice, and the average value of the measurement values of three times in total was used. The smaller the YI value, the less yellow the resin is, and the better the color tone.

6) 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. A polycarbonate resin pellet was sampled every 3 hours during a 24-hour operation, and an average value measured 8 times was used.

7) Measurement of the amount of sulfur element in the polycarbonate resin A sample of the polycarbonate resin is taken in a platinum boat and heated in a quartz tube tubular furnace (AQF-100 type manufactured by Mitsubishi Chemical Corporation), and the sulfur content in the combustion gas is reduced 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).

8) Wavelength dispersibility of retardation of stretched film Polycarbonate resin vacuum-dried at 80 ° C. for 5 hours was converted into a single-screw extruder (made by Isuzu Chemical Industries, screw diameter 25 mm, cylinder setting temperature: 220 ° C.), T-die ( An unstretched film having a thickness of 100 μm ± 10 μm was prepared using a film forming apparatus equipped with a width of 200 mm, a set temperature: 220 ° C., a chill roll (set temperature: 120 to 130 ° C.) and a winder. A sample having a width of 6 cm and a length of 6 cm was cut out from this film.

The sample was uniaxially stretched by a batch type biaxial stretching apparatus [manufactured by Toyo Seiki Sangyo Co., Ltd.] at a stretching speed of 720 mm / min (strain speed of 1200% / min) at a stretching ratio of 2.0 times. 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). The stretching temperature is gradually lowered from the glass transition temperature of the polycarbonate resin + 20 ° C., the stretched film is made 3 times, and a stretched film is created at a temperature 2 ° C. higher than the temperature at which the breakage occurs three times. Used for measurement.

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.

9) (Photoelastic coefficient)
<Sample preparation>
A polycarbonate resin sample (4.0 g), which was vacuum-dried at 80 ° C. for 5 hours, was heated with a hot press at a hot press temperature of 250 ° C. using a spacer having a width of 8 cm, a length of 8 cm, and a thickness of 0.5 mm. After pressurizing under the condition of 20 MPa for 1 minute, the entire spacer was taken out and cooled with a water tube cooling press at a pressure of 20 MPa for 3 minutes, and a sample having a width of 5 mm and a length of 20 mm was cut out.

<Measurement>
Measured using a device that combines a birefringence measuring device composed of a He-Ne laser, a polarizer, a compensation plate, an analyzer, and a photodetector and a vibration type viscoelasticity measuring device ("DVE-3" manufactured by Rheology). . (For details, see Journal of Japanese Society of Rheology, Vol. 19, p93-97 (1991).)

The cut sample was fixed to a viscoelasticity measuring apparatus, and the storage elastic modulus E ′ was measured at a frequency of 96 Hz at a room temperature of 25 ° C. At the same time, the emitted laser light is passed through the polarizer, sample, compensator, and analyzer in this order, picked up by a photodetector (photodiode), and passed through a lock-in amplifier with respect to the amplitude and distortion of the waveform of angular frequency ω or 2ω. The phase difference was determined, and the strain optical coefficient 0 ′ was determined. At this time, the directions of the polarizer and the analyzer were orthogonal to each other, and each was adjusted so as to form an angle of π / 4 with respect to the extending direction of the sample.

The photoelastic coefficient was obtained from the following equation using the storage elastic modulus E ′ and the strain optical coefficient 0 ′.
Photoelastic coefficient = 0 '/ E'

10) Birefringence of stretched film A sample cut into a width of 4 cm and a length of 4 cm from the stretched film prepared in 8) above was used to measure a phase difference of 590 nm using a phase difference measuring device (KOBRA-WPR manufactured by Oji Scientific Instruments). (Re590) was measured. The retardation (Re590) was divided by the thickness (t) of the sample, and birefringence was determined according to the following formula.
Birefringence = Re590 / t

11) Tensile elongation at break of unstretched film The unstretched film prepared in 8) above was cut into a strip shape having a width of 20 mm and a length of 150 mm using a safety razor, and a tensile tester with a thermostatic bath [Toyo Seiki Sangyo Co., Ltd. ), Strograph], the initial chuck distance is 80 mm, the chuck moving speed (tensile speed) is 500 mm / min (625% / min), and the temperature of the thermostatic chamber is set to the glass transition temperature + 6 ° C. The tensile elongation at break was determined by the following formula.

Tensile rupture elongation (%) = length extended until rupture (mm) / distance between chucks (mm) × 100 + 100

12) Measurement of melt viscosity Using a sample which was vacuum-dried at 80 ° C for 5 hours, measurement was performed with a capillary rheometer [manufactured by Toyo Seiki Co., Ltd.]. By heating to the same temperature as the reaction temperature, the melt viscosity was measured at a shear rate of 9.12 to 1824 sec ⁻¹ , and the value of the melt viscosity at 91.2 sec ⁻¹ was used. 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 1-1]
As shown in FIG. 1 described above, a polycarbonate resin was produced under the following conditions using a continuous production apparatus having three vertical stirring reactors and one horizontal stirring reactor.

First, as shown in Table 1, each reactor was previously set to an internal temperature and pressure according to the reaction conditions.
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 treatment rate of 40 kg / hr. The third vertical stirring reactor 6c 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 in the form of a strand and solidified, and then pelletized with a rotary cutter. The process from stranding to pelletization was performed in a clean room. Subsequently, the pellets were sent to the product hopper 16d by pneumatic transfer.

During the production of the polycarbonate resin, the reaction solution corresponding to the outlet of the reactor immediately before the final polymerization reactor from the valve attached after the gear pump 4b is sent from the valve attached after the gear pump 4c to the final polymerization reactor outlet. For the reaction solution corresponding to the above, the polycarbonate resin pellets were sampled 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 the 24 hours and the pelletization was stopped was twice. These results are summarized in Table 2.

[Example 1-2]
The pressure in the third vertical stirring reactor 6c was 22 kPa, and the molecular weight and melt viscosity at the outlet of the third vertical stirring reactor 6c were lower than in Example 1-1. As in Example 1-1, when the conditions of the fourth horizontal stirring reactor 6d 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 The average residence time was 0.6 kPa and 120 minutes. Items not mentioned were the same as in Example 1-1.

Since the reaction time of the fourth horizontal stirring reactor 6d, which is the highest temperature in the reactor, was increased, the color tone of the obtained polycarbonate resin was slightly worse than that of Example 1-1, but 24 hours in the pelletizing step. The number of times of stopping the medium pelletization was 1 time, which was good.

[Example 1-3]
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 as in Example 1-1, the pressure was 1.5 kPa and the average residence time was 100 minutes. Items not mentioned were the same as in Example 1-1.

Since the amounts of the hydroxy terminal and the phenyl carbonate terminal were balanced, the molecular weight increase rate in the fourth horizontal stirring reactor 6d was increased and the pressure was increased, so that the monohydroxy compound content in the polycarbonate resin was increased.
The color tone was good.

[Example 1-4]
The same operation as in Example 1-1 was performed except that the stirring rotation speed of the fourth horizontal stirring 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 resin pellets was remarkably increased. The monohydroxy compound content was lower than in Example 1-1, and the color tone was good.

[Example 1-5]
The same operation as in Example 1-1 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 1-1, the stirring efficiency was lowered, and therefore the phenol content in the obtained polycarbonate resin was increased. The amount of foreign matter has become very small. Moreover, the color tone of the pellet YI was also favorable.

[Example 1-6]
BHEPF, ISB, and DEG were used as the dihydroxy compound (feeding molar 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 1-1 was performed.
A polycarbonate resin having a good color tone and a very small content of monohydroxy compound in the polycarbonate resin and foreign matter was obtained.

[Example 1-7]
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 1-1 was performed.
A polycarbonate resin having a good color tone and a very small content of monohydroxy compound in the polycarbonate resin and foreign matter was obtained.

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

[Comparative Example 1-2]
In Example 1-6, the internal temperature of the third vertical stirring reactor 6c was raised to 230 ° C. When the conditions of the fourth horizontal stirring reactor 6d were adjusted in the same manner as in Example 1-6, the pressure was 0.9 kPa, and the average residence time was 100 minutes. Items not mentioned were the same as in Example 1-6. Compared with Example 1-6, the obtained polycarbonate resin deteriorated in color tone and the monohydroxy compound content also increased.

[Comparative Example 1-3]
In Example 1-7, the internal temperature of the third vertical stirring reactor 6c was raised to 230 ° C. When the conditions of the fourth horizontal stirring reactor 6d were adjusted in the same manner as in Example 1-7, the pressure was 0.8 kPa and the average residence time was 100 minutes. Items not mentioned were the same as in Example 1-7. Compared with Example 1-7, the obtained polycarbonate resin deteriorated in color tone and the monohydroxy compound content also increased.

Table 2 shows the results of Examples 1-1 to 1-7 and Comparative Examples 1-1 to 1-3.

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

[Example 2-1]
As shown in FIG. 1 described above, a polycarbonate resin was produced under the following conditions using a continuous production apparatus having three vertical stirring reactors and one horizontal stirring reactor.

BHEPF, ISB, DEG, and DPC are mixed at a fixed molar ratio (BHEPF / ISB / DEG / DPC = 0.348 / 0.490 / 0.162 / 1.005) in a raw material preparation step in a nitrogen gas atmosphere. And heated to 120 ° C. to obtain a raw material mixed melt.

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 10 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. During the polymerization reaction, the liquid level of each reactor was controlled so that a predetermined average residence time was obtained. The actual operating conditions in these reactors are listed in Table 3.

The capacity of the fourth horizontal stirring reactor 6d was 250 L, the temperature of the heating medium was 242 ° C., the stirring rotation speed was 2 rpm, and the reaction solution was supplied at a throughput of 60 kg / hr.

During the production of the polycarbonate resin, the reaction solution corresponding to the outlet of the final polymerization reactor is sampled from the valve attached after the gear pump 4c, and the polycarbonate resin pellets are sampled after the strand cutter 16b. Carried out. These results are summarized in Table 2.

[Example 2-2]
A polycarbonate resin having a higher molecular weight than that of Example 2-1 was produced by lowering the pressure in the fourth horizontal stirring reactor 6d. In the 4th horizontal stirring reactor 6d, the fluidity of the molten resin has decreased, and it has stopped dripping down to the outlet at the bottom of the tank, so that the molten resin can be stably extracted by lowering the rotation speed of stirring to 1 rpm. Became. When a film was prepared from the obtained polycarbonate resin and stretched, stretching was possible at a stretching temperature lower than that of Example 2-1, and higher in-plane birefringence was obtained.

[Example 2-3]
The same procedure as in Example 2-1 was performed except that the charging ratio of BHEPF, ISB, DEG, and DPC was changed to BHEPF / ISB / DEG / DPC = 0.373 / 0.471 / 0.156 / 1.005. The stretched film had a wavelength difference (Re450 / Re550) of retardation of 0.892, which was stronger than that of Example 2-1. It is possible to obtain desired wavelength dispersion by appropriately adjusting the copolymer composition.

[Example 2-4]
The same procedure as in Example 2-1 was performed except that the charging ratio of BHEPF, ISB, DEG, and DPC was set to BHEPF / ISB / DEG / DPC = 0.373 / 0.523 / 0.104 / 1.005. By reducing the content of DEG compared to Example 2-1, the glass transition temperature of the polycarbonate resin was improved, but the stretchable temperature was increased, and the in-plane retardation of the stretched film was slightly reduced.

[Example 2-5]
BHEPF, ISB, and PEG # 1000 were used as dihydroxy compounds. The charging ratio was BHEPF / ISB / PEG # 1000 / DPC = 0.432 / 0.556 / 0.012 / 1.010. Other than that was carried out similarly to Example 2-1.

[Example 2-6]
Example 2-6, except that the charging ratio of BHEPF / ISB / PEG # 1000 / DPC was BHEPF / ISB / PEG # 1000 / DPC = 0.357 / 0.632 / 0.011 / 1.010 Went to. By reducing the BHEPF content as compared with Example 2-6, the wavelength dispersion of retardation of the stretched film was weakened, but the in-plane retardation was improved.

[Example 2-7]
Example 2-6, except that the charging ratio of BHEPF, ISB, PEG # 1000, and DPC was changed to BHEPF / ISB / PEG # 1000 / DPC = 0.445 / 0.552 / 0.003 / 1.010 Went to. Although the glass transition temperature was improved as compared with the polycarbonate resins of Example 2-1 and Example 2-6, the glass transition temperature was easily broken during stretching, and the film could be stretched only at a high temperature. The in-plane retardation of the stretched film was 0.0009, which was a low value.

[Example 2-8]
BHEPF and ISB were used as dihydroxy compounds. The charging ratio was BHEPF / ISB / DPC = 0.413 / 0.587 / 1.010. Other than that was carried out similarly to Example 2-1. Although the glass transition temperature was improved as compared with the polycarbonate resins of Example 2-1 and Example 2-6, the glass transition temperature was easily broken during stretching, and the film could be stretched only at a high temperature. The in-plane retardation of the stretched film was 0.0008, which was a low value.

[Comparative Example 2-1]
Polymerization was carried out using a batch polymerization apparatus comprising two vertical reactors equipped with a stirring blade and a reflux condenser controlled at 100 ° C. BHEPF and ISB, DEG, DPC, and magnesium acetate in a molar ratio of BHEPF / ISB / DEG / DPC / magnesium acetate = 0.348 / 0.490 / 0.162 / 1.005 / 1.00 × 10 ⁻⁵ It was prepared to become. After sufficiently replacing the inside of the reactor with nitrogen (oxygen concentration 0.0005 to 0.001 vol%), heating was performed with a heating medium, and stirring was started when the internal temperature reached 100 ° C. After 40 minutes from the start of temperature increase, the internal temperature was reached to 220 ° C., and control was performed so as to maintain this temperature. At the same time, pressure reduction was started, and after reaching 220 ° C., the pressure reached 13.3 kPa in 90 minutes. The phenol vapor produced as a by-product with the polymerization reaction was led to a reflux condenser at 100 ° C., and a monomer component contained in a small amount in the phenol vapor was returned to the reactor, and the phenol vapor not condensed was led to a condenser at 45 ° C. and recovered.

Nitrogen was introduced into the first reactor and the pressure was once restored to atmospheric pressure, and then the oligomerized reaction liquid in the first reactor was transferred to the second reactor. Subsequently, the temperature increase and pressure reduction in the second reactor were started, and the internal temperature was 240 ° C. and the pressure was 0.2 kPa in 50 minutes. Thereafter, the polymerization was allowed to proceed to the maximum melt viscosity capable of withdrawing the reaction liquid from the reactor. (The melt viscosity can be controlled by the value of the stirring power of the stirring blade.) When reaching the predetermined power, nitrogen was introduced into the reactor, the pressure was restored, the reaction solution was extracted in the form of a strand, and pelletized with a rotary cutter. .

The reduced viscosity of the obtained polycarbonate resin was 0.356 dL / g, and the molecular weight was lower than that of Example 2-1.

The various analysis was implemented for the obtained polycarbonate resin by the above-mentioned analysis method. Compared to Examples 2-1 and 2-2, the tensile elongation at break was low, and stretching could not be performed unless the stretching temperature was high. The in-plane birefringence of the obtained stretched film was 0.0012, which was a low value.

[Comparative Example 2-2]
Polymerization was performed using a batch polymerization apparatus in the same manner as in Comparative Example 2-1. The same operation as in Comparative Example 2-1 was performed except that the temperature of the second reactor was changed to 255 ° C. The reduced viscosity, tensile elongation at break, and in-plane birefringence of the stretched film of the obtained polycarbonate resin were almost the same as those of Example 2-1, but the color tone of the polycarbonate resin deteriorated because the reaction temperature was increased.

[Comparative Example 2-3]
BHEPF, ISB, and PEG # 1000 were used as dihydroxy compounds. The charging ratio was BHEPF / ISB / PEG # 1000 / DPC = 0.432 / 0.556 / 0.012 / 1.010. Other than that was carried out similarly to Comparative Example 2-1. The obtained polycarbonate resin had a reduced viscosity and a tensile elongation at break as compared with those of Example 2-5, and could only be stretched at a higher temperature. Therefore, the in-plane birefringence of the stretched film was 0.0009. It became a low value.

[Comparative Example 2-4]
BHEPF and ISB were used as dihydroxy compounds. The charging ratio was BHEPF / ISB / DPC = 0.413 / 0.587 / 1.010. Other than that was carried out similarly to Comparative Example 2-1. The obtained polycarbonate resin had a reduced viscosity and a tensile elongation at break as compared with Example 2-8, and could only be stretched at a higher temperature, so that the in-plane birefringence of the stretched film was 0.0008. It became a low value.

[Summary 2]
As shown in Table-3 and Table-4, the polycarbonate resin of the present invention allows the reaction to proceed to a high molecular weight by using a continuous polymerization method, and the tensile breaking elongation is higher than that of the polycarbonate resin obtained by batch polymerization. The degree improved. Therefore, it was possible to perform stretching at a lower temperature, and high in-plane birefringence can be obtained.

Although the present 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 Stirred Reactor 6b Second Vertical Stirred Reactor 6c Third Vertical Stirred Reactor 6d Fourth Horizontal Stirred

Reactor

7a, 7b, 7c Max Blend Blade 7d Two-Axis Glass Stirred

Stirrer

8a, 8b

Internal Heat Exchanger

9a ,

9b Reflux coolers

10a,

10b Reflux pipes

11a, 11b, 11c,

11d Distillate pipes

12a, 12b, 12c,

12d Condensers

13a, 13b, 13c, 13d Depressurizer 14a Distillate recovery tank 15a Twin screw extruder 15b Polymer filter 16a Strand cooling tank

16b Strand cutter

16c Air blower 16d Product hopper 16e meter 16f product bags (paper bags, such as a flexible container bag)

Claims

A method for producing a polycarbonate resin 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 a polycarbonate resin is produced by polycondensation. At least a plurality of devices are connected in series, the internal temperature of the reactor immediately before the final polymerization reactor is 200 ° C. or more and less than 225 ° C., and the outlet of the reactor immediately before the final polymerization reactor The method for producing a polycarbonate resin, wherein the melt viscosity of the reaction solution in is from 20 Pa · s to 1000 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 resin according to claim 1.
1.5 ≦ Q / P ≦ 3.0 (2)
3. The polycarbonate resin according to claim 1, wherein the final polymerization reactor is a horizontal stirring reactor having a plurality of horizontal rotation shafts therein, and the reaction condition satisfies the following formula (3): 3. Production 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 resin 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 resin according to any one of claims 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.
The method for producing a polycarbonate resin according to any one of claims 1 to 5, wherein the temperature of the heating medium of the final polymerization reactor is 220 ° C or higher and 260 ° C or lower.
The polycarbonate resin according to any one of claims 1 to 6, wherein a molar ratio of charged carbonic acid diester to all dihydroxy compounds used in the reaction when first charged into the reactor is 0.990 or more and 1.030 or less. Manufacturing method.
The method for producing a polycarbonate resin according to any one of claims 1 to 7, 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 resin according to any one of claims 1 to 8, wherein the amount is from 1 ppm to 1500 ppm.
The method for producing a polycarbonate resin according to any one of claims 1 to 9, wherein the pressure in the final polymerization reactor is 10 Pa or more and 2 kPa or less.
The method for producing a polycarbonate resin according to any one of claims 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.
The method for producing a polycarbonate resin according to any one of claims 1 to 11, wherein the dihydroxy compound having the fluorene structure is a compound represented by the following formula (1).

[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 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 group 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. 13. The method for producing a polycarbonate resin according to any one of 12 above.

[However, the case where the site represented by the formula (5) is a site constituting a part of —CH 2 —OH and the case where it is a site constituting a part of the dihydroxy compound having the fluorene structure are excluded. ]
The method for producing a polycarbonate resin according to any one of claims 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.
The method for producing a polycarbonate resin according to claim 14, 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 resin according to any one of claims 1 to 15, comprising a step of supplying the polycarbonate resin obtained by polycondensation to a filter in a molten state without solidification and filtering.
The polycarbonate resin obtained by polycondensation, or the resin obtained by filtering it through the filter is discharged from the die head in the form of a strand, and after cooling, pelletized using a cutter. The manufacturing method of the polycarbonate resin of any one.
A polycarbonate resin pellet produced by the production method according to claim 17.
19. The polycarbonate resin pellet according to claim 18, 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.
A transparent film obtained by forming a film of a polycarbonate resin obtained by the production method according to any one of claims 1 to 17.
A stretched film obtained by stretching the transparent film according to claim 20 in at least one direction.
The stretched film according to claim 20 or 21, 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)
A stretched film made of a polycarbonate resin obtained 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 continuously polycondensing the film. A stretched film having in-plane birefringence at 590 nm of 0.0010 or more.
The stretched film according to claim 23, wherein a ratio of a retardation (Re450) measured at a wavelength of 450 nm and a retardation (Re550) measured at a wavelength of 550 nm of the stretched film satisfies the following formula (8).
0.80 ≦ Re450 / Re550 ≦ 0.95 (8)
The stretched film according to claim 23 or 24, wherein the thickness is 80 µm or less.
26. The reactor according to any one of claims 23 to 25, wherein a plurality of the reactors are connected in series, and the final polymerization reactor is a horizontal stirring reactor having a plurality of horizontal rotation shafts therein. Stretched film.
In the final polymerization reactor, when the rotational speed of the stirring blade is ω (rpm) and the melt viscosity of the reaction liquid at the outlet of the reactor is μ (Pa · s), the following formula (3) is satisfied: The stretched film according to any one of 26.
500 ≤ ωμ ≤ 20000 (3)
The stretched film according to any one of claims 23 to 27, wherein the ω is less than 5 rpm.
The stretched film according to any one of claims 23 to 28, wherein the dihydroxy compound having a fluorene structure is a compound represented by the following formula (1).

[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 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 group 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 a fluorene site | part represented by said Formula (1) of Claim 23 thru | or 29 The stretched film of any one of Claims.

[However, the case where the site represented by the formula (5) is a site constituting a part of —CH 2 —OH and the case where it is a site constituting a part of the dihydroxy compound having the fluorene structure are excluded. ]
The stretched film according to any one of claims 23 to 30, 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 stretched film according to any one of claims 23 to 31, wherein the specific dihydroxy compound having a bond structure represented by the formula (5) is a compound having a heterocyclic group represented by the following structural formula (6).
The stretched film according to any one of claims 23 to 32, wherein the polycarbonate resin has a glass transition temperature of 120 ° C or higher and 150 ° C or lower.
The stretched film according to any one of claims 23 to 33, wherein the reduced viscosity of the polycarbonate resin is 0.38 dL / g or more and 0.50 dL / g or less.
The polycarbonate resin is molded into an unstretched film having a thickness of 100 μm ± 10 μm, and stretched until it breaks when subjected to a tensile test at a glass transition temperature of + 6 ° C. and a tensile speed of 625% / min. The stretched film according to any one of claims 23 to 34, wherein a degree (tensile elongation at break) is 220% or more.