JP2012214728A - Method for producing polycarbonate resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently and stably produce a polycarbonate resin excellent in thermostability, hue and mechanical strength with less foreign matter.SOLUTION: A specific dihydroxy compound having -CH-O- site is used as a dihydroxy compound of raw material, a polycarbonate resin obtained by polycondensation thereof is filtered by use of a filter having an aperture of 50 μm or less, discharged in a form of strand from a die at a temperature of 200°C or higher and lower than 280°C, and cooled and solidified, whereby the polycarbonate resin is obtained.

Description

  The present invention relates to a method for efficiently and stably producing a polycarbonate resin which is excellent in thermal stability, hue, and mechanical strength and has few foreign matters.

  Polycarbonate resins generally contain bisphenols as monomer components and take advantage of transparency, heat resistance, mechanical strength, etc., so-called electrical and electronic parts, automotive parts, optical recording media, optical fields such as lenses, etc. Widely used as engineering plastics. However, for optical compensation film applications such as flat panel displays, which have been rapidly spreading recently, more advanced optical properties such as low birefringence and low photoelastic coefficient have been required, and conventional bisphenols are used as monomers. The aromatic polycarbonate resin as a component cannot meet the demand.

  In addition, conventional polycarbonate resins are manufactured using raw materials derived from petroleum resources. However, in recent years, there is a concern about the depletion of petroleum resources, and polycarbonate resins using raw materials obtained from biomass resources such as plants are used. Offer is required. In addition, it is feared that global warming due to the increase and accumulation of carbon dioxide emissions will lead to climate change, etc., so that carbon-neutral plant-derived monomers are used as raw materials even after disposal after use. There is a need for the development of such polycarbonate resins.

  Under such circumstances, there has been proposed a method for obtaining a polycarbonate resin while using a special dihydroxy compound as a monomer component and distilling off a monohydroxy compound by-produced by transesterification with a carbonic acid diester under reduced pressure (for example, Patent Document 1). To 6).

  However, the polycarbonate resin obtained in this way has a problem that foreign matters are mixed in during its production process, etc., and foreign matters are mixed into a molded body molded using the resin, and the commercial value is remarkably lowered. there were. In particular, in optical applications and the like, contamination and coloring of foreign matters were particularly serious problems.

  As a method for reducing the mixing of foreign substances, a method of filtering a resin obtained by polycondensation using a filter is proposed for polycarbonate resins containing bisphenols as monomer components (for example, Patent Documents 7 and 8). .

International Publication No. 04/111106 Pamphlet Japanese Patent Laid-Open No. 2006-232897 JP 2006-28441 A JP 2008-24919 A JP 2009-91404 A JP 2009-91417 A JP-A-5-239334 JP 2000-219737 A

  However, the polycarbonate resin containing a special dihydroxy compound other than bisphenol as a monomer component begins to decompose at a lower temperature than the polycarbonate resin containing a bisphenol as a monomer component, so when attempting to filter at a temperature at which the polycarbonate resin does not decompose. In addition, the viscosity is too high, and there is a problem that the pressure loss in the filter becomes large in a normal filtration area, resulting in damage to the filter, or deterioration of the resin due to shearing heat generation during filtration. Conversely, in order to avoid breakage, a filter having a small pressure loss and low filtration accuracy (a large opening) had to be used.

  In addition, if a filter with high filtration accuracy is used while suppressing deterioration due to filter breakage and resin shear heat generation, the filtration area must be increased, resulting in an increase in the time required for the filtration treatment. Problems such as resin degradation have occurred.

  Furthermore, in order to suppress the pressure loss in the filter and shorten the time required for the filtration process, it is necessary to lower the molecular weight of the polycarbonate resin itself or increase the filtration temperature when trying to lower the melt viscosity of the polycarbonate resin. However, if the molecular weight is lowered, the mechanical strength and heat resistance will be reduced.If the temperature during filtration is increased, the resin will decompose and deteriorate, and it will not be possible to obtain a resin that satisfies the physical properties such as mechanical strength. However, there was a problem that the coloring was promoted or the strands were out of gas by the decomposition gas, so that the pelletization could not be stably obtained.

  These problems are particularly significant when the filter openings are reduced to remove smaller foreign matters or when a high molecular weight resin is filtered. The smaller the filter opening, the greater the differential pressure at the filter, which not only makes the supply of polycarbonate resin unstable, but also causes deterioration of the polycarbonate resin due to damage to the filter and shearing heat as described above. I was there. For this reason, it has been difficult to obtain a polycarbonate resin having a good hue, few foreign matters, and sufficient mechanical strength.

  An object of the present invention is to provide a method for efficiently and stably producing a polycarbonate resin that solves the above-mentioned conventional problems and is excellent in thermal stability, hue, and mechanical strength and has few foreign matters. is there.

  As a result of intensive studies to solve the above problems, the present inventor polycondensed by a transesterification reaction using a catalyst, a specific dihydroxy compound and a carbonic acid diester as raw material monomers, and obtained polycarbonate resin. In the production method, the inventors have found a method for stably producing polycarbonate resin pellets that are excellent in mechanical strength and hue and have few foreign matters by filtering the polycarbonate resin under specific conditions.

That is, the gist of the present invention resides in the following [1] to [23].
[1] A method for producing a polycarbonate resin in which a polycarbonate resin obtained by polycondensation of a dihydroxy compound and a carbonic acid diester is filtered using a filter and then solidified by cooling. It contains at least a dihydroxy compound having a site represented by the general formula (1), the mesh opening of the filter is 50 μm or less, and the temperature of the polycarbonate resin after filtration using the filter is 200 ° C. or more and less than 280 ° C. A method for producing a polycarbonate resin, characterized by being filtered.

（但し、上記一般式（１）で表される部位が−ＣＨ_２−Ｏ−Ｈの一部である場合を除く。）

(However, the site represented by the above general formula (1) unless it is part of _-CH 2 -O-H.)

  [2] The method for producing a polycarbonate resin according to [1], wherein the polycarbonate resin obtained by the polycondensation is supplied to the filter in a molten state without being solidified and filtered.

[3] When the terminal double bond of the polycarbonate resin before being supplied to the filter is X μeq / g and the terminal double bond of the polycarbonate resin obtained by cooling and solidification is Y μeq / g, The method for producing a polycarbonate resin according to [1] or [2], which satisfies formula (2).
Y−X ≦ 10 (2)

[4] When the reduced viscosity (ηsp / c) of the polycarbonate resin before being supplied to the filter is A, and the reduced viscosity (ηsp / c) of the polycarbonate resin obtained by cooling and solidification is B The method for producing a polycarbonate resin according to any one of [1] to [3], which satisfies the following formula (3):
0.8 <B / A <1.1 (3)

[5] The melt viscosity at a shear rate of 91.2 sec ⁻¹ measured at 240 ° C. using the polycarbonate resin obtained by cooling and solidifying is 500 Pa · s to 3000 Pa · s [1] to [4 ] The manufacturing method of the polycarbonate resin of any one of.

  [6] Any one of [1] to [5], wherein the glass transition temperature when measured with a differential scanning calorimeter is 50 ° C. or higher and lower than 160 ° C. using the polycarbonate resin obtained by cooling and solidifying. A method for producing a polycarbonate resin as described in 1. above.

  [7] Using the polycarbonate resin obtained by cooling and solidification, the reduced viscosity (ηsp / c) measured at a concentration of 0.6 g / dL and a temperature of 20.0 ° C. ± 0.1 ° C. in methylene chloride is 0. The method for producing a polycarbonate resin according to any one of [1] to [6], which is 3 dL / g or more and 1.2 dL / g or less.

[8] The filter is stored in a container, and a value obtained by dividing the internal volume (m ³ ) of the storage container by the flow rate (m ³ / min) of the polycarbonate resin to be filtered is 2 minutes to 10 minutes. The method for producing a polycarbonate resin according to any one of [1] to [7].

  [9] Any one of [1] to [8], wherein the content of the aromatic monohydroxy compound contained in the polycarbonate resin obtained by cooling and solidifying is 0.0001 wt% or more and less than 0.1 wt%. The manufacturing method of polycarbonate resin as described in claim | item.

  [10] The method for producing a polycarbonate resin according to any one of [1] to [9], wherein the raw material monomer is filtered with a raw material filter before the polycondensation reaction.

  [11] The method for producing a polycarbonate resin according to any one of [1] to [10], wherein the filter is made of a metal that has been previously roasted at a temperature of 350 ° C. or higher and 500 ° C. or lower.

  [12] The polycarbonate resin before filtration is supplied from the lower part of the storage container of the filter, and the polycarbonate resin after filtration is discharged from the upper part of the storage container. Of producing a polycarbonate resin.

  [13] The polycondensation is performed using a catalyst, and the catalyst is at least one metal compound selected from the group consisting of a metal of Group 2 of the long-period periodic table and lithium [1]. Thru | or the manufacturing method of the polycarbonate resin of any one of [12].

  [14] The method for producing a polycarbonate resin according to any one of [1] to [13], wherein the dihydroxy compound having a site represented by the general formula (1) in a part of the structure is isosorbide. .

  [15] The polycarbonate resin obtained by the above polycondensation is devolatilized by an extruder having a twin screw having a vent port, and then supplied to the filter. A method for producing a polycarbonate resin according to claim 1.

  [16] The screw of the extruder is composed of a plurality of elements, and at least one of the elements is a kneading disk, and the total length of the kneading disk is 20% of the total length of the screw. The method for producing a polycarbonate resin according to [15], which is as follows.

  [17] The method for producing a polycarbonate resin according to [15] or [16], wherein the temperature of the polycarbonate resin supplied to the extruder is 200 ° C. or higher and lower than 250 ° C.

  [18] The method for producing a polycarbonate resin according to any one of [15] to [17], wherein the temperature of the polycarbonate resin supplied to the filter is 220 ° C. or higher and lower than 280 ° C.

[19] When the reduced viscosity (ηsp / c) of the polycarbonate resin supplied to the extruder is a and the reduced viscosity (ηsp / c) of the polycarbonate resin obtained by cooling and solidification is B, the following formula The method for producing a polycarbonate resin according to any one of [15] to [18], which satisfies (4).
0.8 <B / a <1.1 (4)

  [20] The method for producing a polycarbonate resin according to any one of [15] to [19], wherein a gear pump is disposed between the extruder and the filter.

  [21] A polycarbonate resin having a yellow index value of 30 or less obtained by the production method according to any one of [1] to [20].

[22] The polycarbonate resin obtained by the production method according to any one of [1] to [20] or the polycarbonate resin according to [21] having a thickness of 20 μm to 200 μm obtained by extrusion molding A film made of a polycarbonate resin, which is a film, wherein the foreign matter having a maximum length of 25 μm or more contained in the film is 1000 pieces / m ² or less.

（但し、上記一般式（１）で表される部位が−ＣＨ_２−Ｏ−Ｈの一部である場合を除く。） [23] Using a catalyst and a dihydroxy compound and a carbonic acid diester as a raw material monomer, polycondensation is carried out by transesterification, and the resulting polycarbonate resin is filtered using a filter and discharged from the die in the form of a strand, A method of producing a polycarbonate resin pellet using a cutter after cooling, wherein the dihydroxy compound includes at least a dihydroxy compound having a site represented by the following general formula (1) in a part of the structure, A method for producing polycarbonate resin pellets, wherein the mesh opening is 50 μm or less, and the temperature of the resin discharged from the die is 200 ° C. or more and less than 280 ° C.

(However, the site represented by the above general formula (1) unless it is part of _-CH 2 -O-H.)

  According to the present invention, it is excellent in mechanical strength and hue, and has few foreign substances. Electric / electronic parts, automotive parts and other injection molding fields, films, sheet fields, bottles, container fields, camera lenses, viewfinder lenses Films such as CCD and CMOS lenses, retardation films used for liquid crystals and plasma displays, films such as diffusion sheets and polarizing films, sheets, optical disks, optical materials, optical components, dyes, charge transfer agents, etc. It becomes possible to efficiently and stably produce polycarbonate resin pellets having performance applicable to a wide range of fields such as a binder application to be fixed.

Process drawing showing an example of a manufacturing process according to the present invention

  DESCRIPTION OF EMBODIMENTS Embodiments of the present invention will be described in detail below. However, the description of the constituent elements described below is an example (representative example) of an embodiment of the present invention. It is not limited to the contents.

  The method for producing a polycarbonate resin pellet of the present invention is a method for producing a polycarbonate resin in which a polycarbonate resin obtained by polycondensation of a dihydroxy compound and a carbonic acid diester is filtered using a filter and then solidified by cooling. The compound includes at least a dihydroxy compound having a site represented by the following general formula (1) in a part of the structure, the opening of the filter is 50 μm or less, and the temperature of the resin after filtration using the filter is It is characterized by filtering so as to be 200 ° C. or higher and lower than 280 ° C.

（但し、上記一般式（１）で表される部位が−ＣＨ_２−Ｏ−Ｈの一部である場合を除く。）

(However, the site represented by the above general formula (1) unless it is part of _-CH 2 -O-H.)

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

  The dihydroxy compound of the present invention is not particularly limited as long as it has a portion represented by the general formula (1) in a part of its structure, and specifically, diethylene glycol, triethylene Oxyalkylene glycols such as glycol, tetraethylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol; 9,9-bis (4- (2-hydroxyethoxy) phenyl) fluorene, 9,9-bis (4- ( 2-hydroxyethoxy) -3-methylphenyl) fluorene, 9,9-bis (4- (2-hydroxyethoxy) -3-isopropylphenyl) fluorene, 9,9-bis (4- (2-hydroxyethoxy)- 3-isobutylphenyl) fluorene, 9,9-bis (4- (2 Hydroxyethoxy) -3-tert-butylphenyl) fluorene, 9,9-bis (4- (2-hydroxyethoxy) -3-cyclohexylphenyl) fluorene, 9,9-bis (4- (2-hydroxyethoxy)- 3-phenylphenyl) fluorene, 9,9-bis (4- (2-hydroxyethoxy) -3,5-dimethylphenyl) fluorene, 9,9-bis (4- (2-hydroxyethoxy) -3-tert- Butyl-6-methylphenyl) fluorene, 9,9-bis (4- (3-hydroxy-2,2-dimethylpropoxy) phenyl) fluorene, etc., have an aromatic group in the side chain and an aromatic group in the main chain A compound having an ether group bonded to an anhydrosugar alcohol represented by a dihydroxy compound represented by the following general formula (5); Among them, compounds having a cyclic ether structure such as spiroglycol represented by the above formulas are mentioned. Among them, diethylene glycol and triethylene glycol are preferred from the viewpoint of availability, handling, reactivity during polymerization, and hue of the obtained polycarbonate resin. Polyethylene glycol is preferable, and from the viewpoint of heat resistance, an anhydrous sugar alcohol represented by the dihydroxy compound represented by the following general formula (5), and a cyclic ether structure such as spiroglycol represented by the following general formula (6) A compound having (preferably, the site represented by the general formula (1) is a part of a cyclic ether structure) is preferable. These may be used alone or in combination of two or more depending on the required performance of the polycarbonate resin to be obtained.

  Examples of the dihydroxy compound represented by the general formula (5) include isosorbide, isomannide, and isoidet, which are stereoisomers, and these may be used alone or in combination of two or more. You may use it in combination.

  Of these dihydroxy compounds, it is preferable to use a dihydroxy compound having no aromatic ring structure from the viewpoint of the hue of the polycarbonate resin. Among them, it is produced from various starches that are abundant as plant-derived resources and are easily available. Isosorbide obtained by dehydrating and condensing sorbitol is most preferable from the viewpoints of availability and production, light resistance, optical properties, moldability, heat resistance, and carbon neutral.

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

  Among these other dihydroxy compounds, from the viewpoint of the hue of the polycarbonate resin, it is selected from the group consisting of dihydroxy compounds having no aromatic ring structure in the molecular structure, that is, aliphatic dihydroxy compounds and alicyclic dihydroxy compounds. It is preferable to use at least one compound, and as the aliphatic dihydroxy compound, 1,3-propanediol, 1,4-butanediol, and 1,6-hexanediol are particularly preferable. As the alicyclic dihydroxy compound, In particular, 1,4-cyclohexanedimethanol and tricyclodecane dimethanol are preferable. Among these, 1,4-cyclohexanedimethanol is preferable from the viewpoint of polymerization reactivity and toughness improvement.

  By using these other dihydroxy compounds, it is possible to obtain effects such as improvement in flexibility of polycarbonate resin, improvement in heat resistance, improvement in moldability, but structural units derived from other dihydroxy compounds. When the content ratio is too large, mechanical properties and heat resistance may be lowered. Therefore, the ratio of the structural unit derived from the dihydroxy compound of the present invention to the structural unit derived from all dihydroxy compounds is 20 mol. % Or more, preferably 30 mol% or more, particularly preferably 50 mol% or more. That is, the proportion of structural units derived from other dihydroxy compounds is preferably less than 80 mol%, preferably 70 mol% or less, and 50 mol% or less with respect to the structural units derived from all dihydroxy compounds. And particularly preferred.

  The dihydroxy compound of the present invention may contain a stabilizer such as a reducing agent, antioxidant, oxygen scavenger, light stabilizer, antacid, pH stabilizer, heat stabilizer and the like. In particular, since the dihydroxy compound of the present invention is easily altered under acidic conditions, it is preferable to contain a basic stabilizer when stored before use. Basic stabilizers include group 1 or group 2 metal hydroxides, carbonates, phosphates, phosphites, hypophosphites in the long-period periodic table (Nomenclature of Inorganic Chemistry IUPAC Recommendations 2005). Salts, borates, fatty acid salts, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, trimethylethylammonium hydroxide, trimethylbenzylammonium hydroxide, trimethylphenylammonium hydroxide, Triethylmethylammonium hydroxide, triethylbenzylammonium hydroxide, triethylphenylammonium hydroxide Basic ammonium compounds such as roxide, tributylbenzylammonium hydroxide, tributylphenylammonium hydroxide, tetraphenylammonium hydroxide, benzyltriphenylammonium hydroxide, methyltriphenylammonium hydroxide, butyltriphenylammonium hydroxide, 4-amino Pyridine, 2-aminopyridine, N, N-dimethyl-4-aminopyridine, 4-diethylaminopyridine, 2-hydroxypyridine, 2-methoxypyridine, 4-methoxypyridine, 2-dimethylaminoimidazole, 2-methoxyimidazole, imidazole Amine compounds such as 2-mercaptoimidazole, 2-methylimidazole and aminoquinoline. Of these, Na or K phosphates and phosphites are preferred, and hydrogen phosphate 2Na and hydrogen phosphite 2Na are particularly preferred, because of their effects and ease of distillation removal described below.

  The content of these stabilizers in the dihydroxy compound of the present invention is not particularly limited, but if it is too small, the effect of preventing alteration of the dihydroxy compound of the present invention may not be obtained. Since modification of the compound may be caused, it is usually 0.0001% by weight to 1% by weight, preferably 0.001% by weight to 0.1% by weight, based on the dihydroxy compound of the present invention.

  In addition, when the dihydroxy compound of the present invention has a cyclic ether structure such as isosorbide, it is easily oxidized by oxygen. Therefore, during storage and production, in order to prevent decomposition by oxygen, do not mix moisture, In addition, it is important to use an oxygen scavenger or the like and handle under a nitrogen atmosphere. In particular, when isosorbide is oxidized, decomposition products such as formic acid may be generated. If isosorbide containing these decomposition products is used as a raw material for the production of polycarbonate resin, it may lead to coloration of the resulting polycarbonate resin, and may not only significantly deteriorate the physical properties but also affect the polymerization reaction. In some cases, a high molecular weight polymer cannot be obtained.

(Carbonated diester)
In the present invention, a polycarbonate resin can be obtained by polycondensation by a transesterification reaction using a dihydroxy compound containing the dihydroxy compound of the present invention described above and a carbonic acid diester as raw materials. Examples of the carbonic acid diester used in the present invention include those represented by the following general structural formula (7). These carbonic acid diesters may be used alone or in combination of two or more.

（Ａ^１、Ａ^２は、置換または無置換の炭素数１〜１８の脂肪族または置換または無置換の芳香族基であり、Ａ^１とＡ^２は同一であっても異なっていてもよい。）
Ａ^１及びＡ^２は置換もしくは無置換の芳香族炭化水素基が好ましく、無置換の芳香族炭化水素基がより好ましい。尚、脂肪族炭化水素基の置換基としては、エステル基、エーテル基、カルボン酸、アミド基、ハロゲンが挙げられ、芳香族炭化水素基の置換基としては、メチル基、エチル基等のアルキル基が挙げられる。

(A ¹ and A ² are substituted or unsubstituted C 1-18 aliphatic or substituted or unsubstituted aromatic groups, and A ¹ and A ² may be the same or different. )
A ¹ and A ² are preferably a substituted or unsubstituted aromatic hydrocarbon group, and more preferably an unsubstituted aromatic hydrocarbon group. In addition, examples of the substituent of the aliphatic hydrocarbon group include an ester group, an ether group, a carboxylic acid, an amide group, and a halogen. Examples of the substituent of the aromatic hydrocarbon group include an alkyl group such as a methyl group and an ethyl group. Is mentioned.

  Examples of the carbonic acid diester represented by the general formula (7) include substituted diphenyl carbonates such as diphenyl carbonate and ditolyl carbonate, dimethyl carbonate, diethyl carbonate, and di-t-butyl carbonate. Diphenyl carbonate and substituted diphenyl carbonate are preferable, and diphenyl carbonate is particularly preferable. Carbonic acid diesters may contain impurities such as chloride ions, which may hinder the polymerization reaction or worsen the hue of the resulting polycarbonate resin. It is preferable to use what was done.

  In the method of the present invention, a polycarbonate resin can be obtained by polycondensation of a dihydroxy compound containing the dihydroxy compound of the present invention and a carbonic acid diester by an ester exchange reaction. The dihydroxy compound and carbonic acid diester as raw materials can be transesterified even if they are dropped independently into the reaction vessel, but they can also be mixed uniformly before the transesterification. The mixing temperature is preferably 80 ° C. or higher, preferably 90 ° C. or higher, and the upper limit thereof is preferably 250 ° C. or lower, preferably 200 ° C. or lower, more preferably 150 ° C. or lower. Among these, 100 ° C. or higher and 130 ° C. or lower is preferable. If the mixing temperature is too low, the dissolution rate may be slow or the solubility may be insufficient, often causing problems such as solidification, and if the mixing temperature is too high, the dihydroxy compound may be thermally deteriorated. As a result, the hue of the polycarbonate resin obtained is deteriorated, which may adversely affect light resistance and heat resistance.

  In the method of the present invention, the oxygen concentration in the operating environment in which the dihydroxy compound containing the dihydroxy compound of the present invention as a raw material and the carbonic acid diester are mixed is preferably 10 vol% or less, more preferably 0.0001 vol% to 10 vol%, and in particular, 0 From the viewpoint of preventing deterioration of hue, it is preferable to carry out in an atmosphere of 0.0001 vol% to 5 vol%, particularly 0.0001 vol% to 1 vol%.

  In the present invention, the carbonic acid diester may be used in a molar ratio of 0.90 to 1.20, preferably 0.95 to 1.10, based on all dihydroxy compounds including the dihydroxy compound of the present invention used in the reaction. More preferably, it is 0.97 to 1.03, and particularly preferably 0.99 to 1.02. When this molar ratio is decreased, the terminal hydroxyl group of the produced polycarbonate resin is increased, the thermal stability of the polymer is deteriorated, coloring occurs during molding, the rate of transesterification reaction is reduced, and the desired high molecular weight. The body may not be obtained. On the other hand, when this molar ratio is increased, the rate of transesterification reaction decreases, the production of polycarbonate having a desired molecular weight becomes difficult, the amount of residual carbonic diester in the polycarbonate resin increases, and during extrusion and molding In some cases, gas may be generated. The decrease in the transesterification reaction rate may increase the thermal history during the polymerization reaction and may deteriorate the hue of the resulting polycarbonate resin.

  Furthermore, when the molar ratio of the carbonic diester is increased with respect to all the dihydroxy compounds including the dihydroxy compound of the present invention, the amount of residual carbonic diester in the obtained polycarbonate resin increases, which becomes a gas at the time of molding and causes molding defects. Bleed out from the product, which is not preferable. The concentration of the carbonic acid diester remaining in the polycarbonate resin pellet obtained by the method of the present invention is preferably 200 ppm by weight or less, more preferably 100 ppm by weight or less, particularly preferably 60 ppm by weight or less, and particularly preferably 30 ppm by weight or less. is there.

(catalyst)
In the method of the present invention, as described above, when a polycarbonate resin is produced by polycondensation of a dihydroxy compound containing the dihydroxy compound of the present invention and a carbonic acid diester by a transesterification reaction, a transesterification catalyst (hereinafter simply referred to as “catalyst”). Or “polymerization catalyst”) can be present.

  In the method of the present invention, the transesterification catalyst (catalyst) can particularly affect the thermal stability of the polycarbonate resin and the yellow index (YI) value representing the hue. The transesterification catalyst used is not limited as long as it satisfies the thermal stability and hue of the polycarbonate resin, but is not limited to Group 1 or Group 2 in the long-period periodic table (hereinafter simply referred to as “1”). Group compounds ”and“ group 2 ”), and basic compounds such as basic boron compounds, basic phosphorus compounds, basic ammonium compounds, and amine compounds. Preferably, Group 1 metal compounds and / or Group 2 metal compounds are used. More preferably, it is a metal compound of a metal selected from the group consisting of a long-period group 2 metal and lithium.

  The group 1 metal compound and / or group 2 metal compound is usually used in the form of a hydroxide or a salt such as a carbonate, carboxylate, or phenol salt. From the viewpoint of easiness, a hydroxide, carbonate, and acetate are preferable, and acetate is preferable from the viewpoint of hue and polymerization activity.

  Specific 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, and carbonic acid. Potassium, lithium carbonate, cesium carbonate, sodium acetate, potassium acetate, lithium acetate, cesium acetate, sodium stearate, potassium stearate, lithium stearate, cesium stearate, sodium borohydride, potassium borohydride, lithium borohydride Cesium borohydride, sodium borohydride, potassium borohydride, lithium phenyl borohydride, cesium phenyl borohydride, sodium benzoate, potassium benzoate, lithium benzoate, cesium benzoate, phosphorus 2 sodium hydrogen, 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, Examples thereof include lithium, cesium alcoholate, phenolate, bisphenol A disodium salt, 2 potassium salt, 2 lithium salt, 2 cesium salt, etc. Among them, lithium compounds are preferred.

  Specific examples of the Group 2 metal compound include calcium hydroxide, barium hydroxide, magnesium hydroxide, strontium hydroxide, calcium hydrogen carbonate, barium hydrogen carbonate, magnesium hydrogen carbonate, strontium hydrogen carbonate, calcium carbonate. , Barium carbonate, magnesium carbonate, strontium carbonate, calcium acetate, barium acetate, magnesium acetate, strontium acetate, calcium stearate, barium stearate, magnesium stearate, strontium stearate, etc., among which magnesium compounds, calcium compounds, barium compounds And at least one metal selected from the group consisting of magnesium compounds and calcium compounds from the viewpoint of polymerization activity and hue of the polycarbonate resin obtained More preferably compounds, most preferably a calcium compound.

  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, since it may volatilize during the polymerization reaction and cause trouble, it is particularly preferable to use only the Group 1 metal compound and / or the Group 2 metal compound.

  Examples of the basic boron compound that can be used in combination include tetramethylboron, tetraethylboron, tetrapropylboron, tetrabutylboron, trimethylethylboron, trimethylbenzylboron, trimethylphenylboron, triethylmethylboron, triethylbenzylboron, and triethyl. Sodium salt, potassium salt, lithium salt, calcium salt, barium salt, magnesium salt, such as phenyl boron, tributyl benzyl boron, tributyl phenyl boron, tetraphenyl boron, benzyl triphenyl boron, methyl triphenyl boron, butyl triphenyl boron, or Examples include strontium salts.

  Examples of the basic phosphorus compound that can be used in combination include triethylphosphine, tri-n-propylphosphine, triisopropylphosphine, tri-n-butylphosphine, triphenylphosphine, tributylphosphine, or a quaternary phosphonium salt. It is done.

  Examples of the basic ammonium compound that can be used in combination include tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, trimethylethylammonium hydroxide, trimethylbenzylammonium hydroxide, and trimethyl. Phenylammonium hydroxide, triethylmethylammonium hydroxide, triethylbenzylammonium hydroxide, triethylphenylammonium hydroxide, tributylbenzylammonium hydroxide, tributylphenylammonium hydroxide, tetraphenylammonium hydroxide, benzyltriphenylammonium hydroxide, methyltrimethyl Phenyla Mode onium hydroxide, butyl triphenyl ammonium hydroxide, and the like.

  Examples of the amine compound that can be used in combination include 4-aminopyridine, 2-aminopyridine, N, N-dimethyl-4-aminopyridine, 4-diethylaminopyridine, 2-hydroxypyridine, 2-methoxypyridine, 4 -Methoxypyridine, 2-dimethylaminoimidazole, 2-methoxyimidazole, imidazole, 2-mercaptoimidazole, 2-methylimidazole, aminoquinoline and the like.

  The amount of the catalyst used is preferably 0.1 μmol to 300 μmol, preferably 0.5 μmol to 100 μmol, more preferably 0.5 μmol to 50 μmol, even more preferably 0.5 μmol to It is 20 μmol, and more preferably 1 μmol to 5 μmol. In particular, when using at least one metal compound selected from the metals of Group 2 of the long-period periodic table and lithium, the amount of metal is usually 0.1 μmol or more, preferably 0.5 μmol, per 1 mol of all dihydroxy compounds used. As described above, particularly preferably 0.7 μmol or more. Further, the upper limit is usually 20 μmol, preferably 10 μmol, more preferably 3 μmol, particularly preferably 1.5 μmol, and most preferably 1.0 μmol.

  On the other hand, if the amount of the catalyst used is too large, the hue or thermal stability of the polycarbonate resin obtained by an undesired side reaction may deteriorate. In addition, Group 1 metals, especially sodium, potassium, and cesium, especially sodium, may adversely affect the hue when contained in a large amount in the polycarbonate resin. The metal is not only from the catalyst used, but also from raw materials and reactors. The total amount of these compounds in the polycarbonate resin is usually 1 ppm by weight or less, preferably 0.8 ppm by weight or less, more preferably 0.7 ppm by weight or less as the amount of metal. . The amount of metal in the polycarbonate resin can be measured using a method such as atomic emission, atomic absorption, Inductively Coupled Plasma (ICP) after recovering the metal in the polycarbonate resin by a method such as wet ashing. I can do it.

  The catalyst may be added directly to the reactor, or may be added to a raw material adjusting tank in which a dihydroxy compound and a carbonic acid diester are mixed in advance, and then present in the reactor. You may add in the piping which supplies a raw material. If the amount of the catalyst used is too small, sufficient polymerization activity cannot be obtained and the progress of the polymerization reaction is delayed, so that it is difficult to obtain a polycarbonate resin having a desired molecular weight, and a long-term heat history is caused. Can get worse.

<Manufacturing method>
(Polycondensation method)
In the method of the present invention, the method for obtaining a polycarbonate resin by polycondensation of the dihydroxy compound and the carbonic acid diester may be carried out in multiple stages using a plurality of reactors in the presence of the catalyst. The type of reaction may be any of batch type, continuous type, or a combination of batch type and continuous type. Among these, the continuous type is preferable from the viewpoint of stabilizing the quality. In the initial stage of polymerization, it is preferable to obtain a prepolymer at a relatively low temperature and low vacuum, and in the latter stage of polymerization, it is preferable to increase the molecular weight to a predetermined value at a relatively high temperature and high vacuum, but the jacket temperature at each molecular weight stage. It is important from the viewpoints of hue and thermal stability to appropriately select the internal temperature and pressure in the reaction system. For example, if either the temperature or the pressure is changed too quickly before the polymerization reaction reaches a predetermined value, the unreacted monomer will be distilled, causing the molar ratio of the dihydroxy compound and the carbonic acid diester to change, resulting in a decrease in the polymerization rate. Or a polymer having a predetermined molecular weight or terminal group cannot be obtained, and as a result, the object of the present invention may not be achieved.

  Furthermore, it is effective to use a reflux condenser for the polymerization reactor in order to suppress the amount of the monomer to be distilled off, and the effect is particularly great in a reactor at the initial stage of polymerization where there are many unreacted monomer components. The temperature of the refrigerant introduced into the reflux condenser can be appropriately selected according to the monomer used, but the temperature of the refrigerant introduced into the reflux condenser is usually 45 to 180 ° C. at the inlet of the reflux condenser. Yes, preferably 80 to 150 ° C, particularly preferably 100 to 140 ° C. If the temperature of the refrigerant is too high, the amount of reflux decreases and the effect is reduced. On the other hand, if the temperature is too low, the distillation efficiency of the monohydroxy compound that should be distilled off tends to decrease. As the refrigerant, hot water, steam, heat medium oil or the like is used, and steam or heat medium oil is preferable.

  In order to maintain the polymerization rate appropriately and suppress the distillation of the monomer while suppressing the occurrence of foreign matter in the final polycarbonate resin and not impairing the hue and thermal stability, Selection of type and quantity is important. In the present invention, it is preferable to produce the catalyst by polymerizing in multiple stages using a plurality of reactors. The reason for carrying out the polymerization in a plurality of reactors is that at the initial stage of the polymerization reaction, since there are many monomers contained in the reaction liquid, it is important to suppress the volatilization of the monomers while maintaining the necessary polymerization rate. In the latter stage of the polymerization reaction, it is important to sufficiently distill off the by-produced monohydroxy compound in order to shift the equilibrium to the polymerization side, and desirable polymerization reaction conditions differ between the initial stage and the latter stage. Thus, in order to set different polymerization reaction conditions, it is preferable from the viewpoint of production efficiency to use a plurality of polymerization reactors arranged in series.

  As described above, the number of reactors used in the polymerization in the present invention may be at least two. However, from the viewpoint of production efficiency, three or more, preferably 3 to 5, particularly preferably. Is four. In the present invention, if there are two or more reactors, different reaction conditions can be set in each reactor, and the temperature and pressure are continuously changed in each reactor. May be.

  In the present invention, the polymerization catalyst can be added to the raw material preparation tank, the raw material storage tank, or can be added directly to the polymerization tank. From the viewpoint of supply stability and polymerization control, the polymerization catalyst is added to the polymerization tank. A catalyst supply pipe may be installed in the middle of the raw material pipe before being supplied, and is preferably supplied as an aqueous solution.

  If the temperature of the polymerization reaction is too low, it causes a decrease in productivity and an increase in the thermal history of the product, and if it is too high, it not only causes the vaporization of monomers but also may promote the decomposition and coloring of the polycarbonate resin. .

  The specific temperature is as follows. In the first stage reaction, the maximum internal temperature of the polymerization reactor is preferably 140 to 270 ° C., preferably 170 to 240 ° C., more preferably 180 to 210 ° C., and preferably 110 to 1 kPa, preferably 70 to 5 kPa, more preferably 30 to 10 kPa (absolute pressure) for 0.1 to 10 hours, preferably 0.5 to 3 hours, while distilling off the by-produced monohydroxy compound out of the reaction system Is done. The reaction in the first stage in the present invention refers to a reaction in a reactor at the uppermost stream of the process in a reactor in which 5% by weight or more of a monohydroxy compound distilled through the entire polymerization reaction is distilled. .

  In the second and subsequent stages, the pressure in the reaction system is gradually reduced from the pressure in the first stage, and the monohydroxy compound that is subsequently generated is removed from the reaction system. 2 kPa or less, preferably 1 kPa or less, 210 ° C. or more, preferably 220 ° C. or more, 270 ° C. or less, preferably 250 ° C. or less, more preferably 240 ° C. or less, and 0.1 to 10 hours, preferably 1 to 6 hours, particularly preferably 0.5 to 3 hours.

  In particular, in order to suppress the coloring and thermal deterioration of the polycarbonate resin and obtain a polycarbonate resin having a good hue and thermal stability, the maximum internal temperature in all reaction stages is less than 260 ° C., preferably less than 250 ° C., particularly 245 It is preferable that it is less than ° C. The internal temperature here refers to the temperature of the process liquid, and is usually measured by a thermometer using a thermocouple or the like provided in the reactor. In order to suppress the decrease in the polymerization rate after the polymerization reaction and minimize deterioration due to thermal history, it is necessary to use a horizontal reactor with excellent plug flow and interface renewability at the final stage of polymerization. preferable. However, in order to obtain a polycarbonate resin having a predetermined molecular weight, it should be noted that the yellow index (YI) value representing the hue tends to increase if the polymerization temperature is increased and the polymerization time is excessively increased.

  The monohydroxy compound distilled off as a by-product in the reaction is preferably used as a raw material for fuels and chemicals from the viewpoint of effective utilization of resources. In particular, it is preferable to recycle as raw materials such as diphenyl carbonate and bisphenol A after purification as necessary.

(Process after polycondensation reaction)
The polycarbonate resin of the present invention is filtered using a filter after performing the above-mentioned polycondensation reaction. In particular, the polycarbonate resin obtained by polycondensation is introduced into an extruder and then discharged from the extruder in order to remove low molecular weight components contained in the polycarbonate resin and to add and knead a heat stabilizer and the like. Is preferably filtered using a filter.

Examples of a method for filtering the polycarbonate resin obtained by polycondensation as described above using a filter include the following methods.
In order to generate the pressure required for filtration, a polycarbonate resin is extracted from the final polymerization reactor in a molten state using a gear pump or a screw, and filtered through the filter.
Polycarbonate resin is supplied from a final polymerization reactor to a uniaxial or biaxial extruder in a molten state, melt extruded, filtered through the filter, cooled and solidified in the form of a strand, and pelletized with a rotary cutter or the like. Method,
Polycarbonate resin is supplied to a single-screw or twin-screw extruder in a molten state without being solidified from the final polymerization reactor, melt-extruded, then cooled and solidified in the form of a strand, pelletized, and the pellet is extruded again. A method of introducing into a machine and filtering with the filter, cooling and solidifying in the form of a strand, and pelletizing,
Alternatively, the polycarbonate resin is extracted from the final polymerization reactor in a molten state, cooled and solidified in the form of strands without passing through an extruder, and once pelletized, then the pellets are supplied to a single or twin screw extruder and melted. After extruding, it is filtered by the filter, cooled and solidified in the form of a strand, and pelletized.
Above all, in order to minimize thermal history and suppress thermal degradation such as deterioration of hue and molecular weight, the resin is put into a single or twin screw extruder in a molten state without solidifying from the final polymerization reactor. A method of feeding, melting and extruding, supplying to the filter using a gear pump, filtering, discharging from a die, cooling and solidifying in the form of a strand, and pelletizing with a rotary cutter or the like is preferable.

<Example of manufacturing equipment>
An apparatus for carrying out the present invention to obtain pellets of a polycarbonate resin obtained by cooling and solidification from the raw material monomers described above (hereinafter, “cooled and solidified polycarbonate resin” may be simply referred to as “polycarbonate resin”) An example is shown in the process diagram of FIG. Isosorbide (ISB) is used as the raw material monomer of the present invention as dihydroxy compound of the present invention, 1,4-cyclohexanedimethanol (CHDM) is used as the other dihydroxy compound, diphenyl carbonate (DPC) is used as the carbonic acid diester, and calcium acetate is used as the polymerization catalyst. It shall be.

  First, in the raw material preparation step, a DPC melt prepared at a predetermined temperature in a nitrogen gas atmosphere is continuously supplied from the raw material supply port 1a to the raw material mixing tank 2a. Also, the ISB melt and the CHDM melt measured in a nitrogen gas atmosphere are continuously supplied to the raw material mixing tank 2a from the raw material supply ports 1b and 1c, respectively. And these are mixed by the stirring blade 3a within the raw material mixing tank 2a, and a raw material mixing melt is obtained.

  Next, the obtained raw material mixed melt is continuously supplied to the first vertical stirring reaction tank 6a via the raw material supply pump 4a and the raw material filtration filter 5a. Further, the raw material catalyst is continuously supplied as an aqueous solution from the catalyst supply port 1d in the middle of the raw material mixed melt transfer pipe.

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

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

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

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

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

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

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

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

<Details of pellet manufacturing process after polymerization reaction>
(Extruder)
In the present invention, the form of the extruder is not limited, but a uniaxial or biaxial extruder is used. Among them, a twin screw extruder is preferable for improving the devolatilization performance described later and for uniform kneading of the additive. In this case, the rotation direction of the shaft may be different or the same, but the same direction is preferable from the viewpoint of kneading performance. Not only can the supply of the polycarbonate resin to the filter be stabilized by the use of an extruder, but also devolatilization and additive kneading can be carried out simultaneously.

  In addition, in the polycarbonate resin obtained by polycondensation as described above, hue, heat stability, raw material monomers that may adversely affect the product due to bleed-out, etc. Low molecular weight compounds such as hydroxy compounds and polycarbonate oligomers often remain, but those having a vent port as the extruder are preferably used 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 the said extruder, and devolatilization can also be accelerated | stimulated. The number of vent ports may be one or plural, but preferably two or more.

  Furthermore, additives such as a thermal stabilizer, a release agent, and a colorant, which will be described later, can be kneaded using the extruder.

  Furthermore, in order to suppress thermal deterioration of the polycarbonate resin in the extruder, the rotational speed of a shaft (hereinafter sometimes referred to as a screw) provided in the extruder is 300 rpm or less, preferably 250 rpm or less, more preferably 200 rpm or less. When the rotational speed of the screw exceeds 300 rpm, the shear heat generation of the polycarbonate resin increases, leading to deterioration of hue and molecular weight. On the other hand, if the number of rotations of the screw is too small, not only may the devolatilization performance deteriorate and the additive kneading performance deteriorates, but the processing amount per unit time decreases, leading to deterioration in productivity. Therefore, it is preferably 50 rpm or more, more preferably 70 rpm or more.

  And the peripheral speed of the screw is appropriately determined by the screw diameter and the number of rotations of the extruder, but in order to suppress thermal deterioration such as coloring and molecular weight reduction due to heat generation due to shearing of the polycarbonate resin, Usually 1.0 m / sec or less, preferably 0.6 m / sec or less, particularly preferably 0.4 m / sec or less. On the other hand, if the peripheral speed becomes too low, venting up during vacuum devolatilization tends to occur, and devolatilization performance and additive dispersion performance tend to decrease. 1 m / sec or more.

  Usually, the screw of an extruder is composed of a plurality of elements (screw elements) in order to give various functions, and generally only a spiral screw (flight) mainly for the purpose of transporting resin. Consists of a full flight consisting of a kneading disk for resin kneading, a seal ring for resin sealing, etc., depending on the purpose, reverse flight with a screw in the direction opposite to the resin transport direction is also used It is done. There are two- and three-row types depending on how the screw is cut. In the present invention, a double-row type deep groove type that can take a large amount of processing with respect to the screw diameter of the extruder and can suppress shearing heat generated by screw rotation. Is preferred.

  In the present invention, the configuration of these screw elements is not limited, but it is preferable to have a kneading disk. Among them, the total length of the kneading disk is 20% of the total length of the screw. % Or less, more preferably 15% or less, and most preferably 10% or less. If the total length of the kneading disk is too long, local heat generation due to the shearing of the resin increases, and problems such as deterioration of the hue and molecular weight of the polycarbonate resin tend to occur. On the other hand, if the total length of the kneading disk is too short, the performance at the time of devolatilization and kneading of the additive may be deteriorated. It is preferably 3% or more of the length, and more preferably 5% or more.

  The kneading disk includes a forward feed type, an orthogonal type, and a reverse feed type with respect to the resin transport direction, and can be appropriately selected according to the viscosity of the resin used and the required performance.

  As the material of the screw element, it is preferable to increase the surface nickel content or the like to keep the iron content low, or to treat the surface hardness with TiN or CrN.

  In the present invention, the temperature of the resin when the polycarbonate resin is supplied in the molten state to the extruder is preferably 200 ° C. or higher, and particularly preferably 210 ° C. or higher, particularly 220 ° C. or higher. Further, the upper limit is preferably less than 250 ° C., more preferably less than 245 ° C., particularly preferably less than 240 ° C. If the temperature of the polycarbonate resin supplied to the extruder is too low, not only the melt viscosity of the polycarbonate resin becomes too high and the supply may become unstable, but also the shear heat generation in the extruder increases and the polycarbonate resin When the temperature is too high, the polycarbonate resin is likely to be deteriorated, and there is a tendency that the hue is deteriorated, the molecular weight is lowered, and the mechanical strength is lowered accordingly.

  The temperature of the polycarbonate resin supplied to the extruder is controlled by a method such as controlling the internal temperature of the final polymerization reactor, controlling the temperature of the piping supplying the polycarbonate resin to the extruder, or installing a heat exchanger. can do.

  In the present invention, the temperature of the polycarbonate resin discharged from the extruder is preferably less than 280 ° C, more preferably less than 270 ° C, and particularly preferably less than 260 ° C. When the polycarbonate resin discharged from the extruder is 280 ° C. or higher, the polycarbonate resin is likely to be deteriorated, which tends to cause a deterioration in hue, a decrease in molecular weight, and a decrease in mechanical strength associated therewith. Conversely, if the temperature of the polycarbonate resin discharged from the extruder becomes too low, the melt viscosity of the polycarbonate resin is high, the load on the extruder increases, screw rotation becomes unstable, and the motor is overloaded. Therefore, it is preferably 220 ° C. or higher, more preferably 230 ° C. or higher, and particularly preferably 240 ° C. or higher. Usually, in an extruder, heat is generated by shearing of the resin accompanying the rotation of the screw, and generally the temperature of the discharged polycarbonate resin tends to be higher than the temperature of the supplied polycarbonate resin. This tendency becomes significant when the molecular weight is high and the melt viscosity is high. Increasing the temperature of the polycarbonate resin tends to reduce the melt viscosity, and the amount of shear heat generation can be suppressed by that amount. Since there is a tendency to cause a decrease in mechanical strength, it is not easy to perform extrusion by preventing deterioration of a polycarbonate resin having high viscosity that is inferior in thermal stability.

  The temperature of the polycarbonate resin discharged from the extruder is usually controlled by the temperature of the polycarbonate resin to be supplied and the temperature of the heater attached to the barrel, but the amount of polycarbonate resin supplied to the extruder and the temperature of the extruder Since this may vary depending on the number of screw rotations, it is preferable to control these conditions together.

  Especially in the case of polycarbonate resin with high viscosity, shear heat generation due to screw rotation increases, and the temperature of the discharged resin tends to rise with respect to the temperature of the supplied resin. Therefore, dispersion of additives, devolatilization performance, and productivity In order to suppress the deterioration of the polycarbonate resin due to the shear heat generation while maintaining the above, it is important to select the number of rotations of the screw, the peripheral speed, and the element configuration.

(filter)
In the present invention, filtration is performed with a filter in order to remove foreign matters such as burns and gels in the polycarbonate resin obtained by polycondensation. Above all, it is possible to remove residual monomer and by-product phenol by vacuum devolatilization and to extrude polycarbonate resin with an extruder and filter with a filter in order to mix additives such as heat stabilizer and mold release agent. preferable.

  As the form of the filter, known ones such as a candle type, a pleat type, a leaf disk type can be used. Among them, a leaf disk type that can take a large filtration area with respect to the storage container of the filter is preferable, and a large filtration area can be taken. Thus, it is preferable to use a plurality of combinations. The leaf disk type filter is configured by combining a holding member (also referred to as a retainer) with a filtering member (hereinafter also referred to as a medium), and the filters (in some cases, a plurality or a plurality of filters). ) Used in the form of a unit (sometimes called a filter unit) stored in a containment vessel.

  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.

In the present invention, the aperture of the filter is preferably not more than 50 μm, more preferably not more than 30 μm, still more preferably not more than 20 μm, and preferably not more than 15 μm in order to reduce foreign matters. If the opening 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. It is preferable. Here, the aperture defined as 99% filtration accuracy refers to the value of χ when the βχ value represented by the following formula (8) determined in accordance with ISO 16889 is 100.
βχ = (number of particles on the primary side larger than χ μm) / (number of particles on the secondary side larger than χ μm) (8)
(Here, the primary side is before filtration with a filter, and the secondary side is after filtration.)

  The material of the filter media is not limited as long as it has the strength and heat resistance required for resin filtration, but stainless steel such as SUS316 and SUS316L, which have a low iron content, is particularly preferable. In addition, as the type of weaving, non-woven fabric types can be used in addition to regular weaving portions such as plain weave, twill weave, plain tatami mat, twill mat weave, etc. 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 addition, if the filter contains an iron component, the resin tends to deteriorate during filtration at a high temperature exceeding 200 ° C. Therefore, as described above, in the case of stainless steel, the iron content is small. In addition, it is preferable to passivate it before use. Passivation treatment is a method in which the filter is immersed in an acid such as nitric acid, or an acid is passed through the filter to form a passive state on the surface, which is roasted (heated) in the presence of water vapor or oxygen. Examples thereof include a method and a method using these in combination, and it is preferable to perform both nitric acid treatment and roasting.

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

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

  It is preferable that the filter is stored in a storage container because it facilitates filtration by applying pressure. The material of the containment vessel is not limited as long as it has strength and heat resistance that can withstand resin filtration, but is preferably a stainless steel such as SUS316 or SUS316L with a low iron content. If the iron content is large, the polycarbonate resin may be deteriorated as described above.

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

Moreover, if the value obtained by dividing the internal volume (m ³ ) of the filter storage container by the polycarbonate resin flow rate (m ³ / min) is too small, the differential pressure of the filter may increase and the filter may be damaged. If it is too large, the polycarbonate resin is deteriorated at the time of filtration, so it is preferably 1 minute to 20 minutes, preferably 2 minutes to 10 minutes, more preferably 2 minutes to 5 minutes.

  In the method of the present invention, the temperature of the polycarbonate resin before filtration supplied to the filter is preferably less than 280 ° C, more preferably less than 270 ° C, particularly preferably less than 265 ° C, and particularly preferably less than 260 ° C. It is. When the temperature before filtering with the filter is 280 ° C. or higher, thermal deterioration in the filter unit is likely to occur, and there is a tendency to cause deterioration in hue, molecular weight, and accompanying mechanical strength. Conversely, if the temperature before filtration with the filter becomes too low, the melt viscosity of the polycarbonate resin is high, the load on the filter increases, and the filter may be damaged. ° C or higher, more preferably 230 ° C or higher, particularly preferably 240 ° C or higher.

Moreover, in this invention, it is preferable that the resin temperature after filtration shall be 200 degreeC or more, More preferably, it is 220 degreeC or more, More preferably, it is 230 degreeC or more. If the temperature of the polycarbonate resin after filtration using the filter is too low, the melt viscosity becomes high and the extruded strands are not stable and tend to be difficult to be pelletized with a rotary cutter or the like. There is. On the other hand, the resin temperature after filtration is preferably less than 280 ° C, more preferably less than 270 ° C, further preferably less than 265 ° C, and still more preferably less than 260 ° C. If the temperature of the polycarbonate resin after filtration using the filter is too high, the polycarbonate resin is likely to be thermally deteriorated, which tends to cause a deterioration in hue, a decrease in molecular weight, and a decrease in mechanical strength associated therewith.
The resin temperature after filtration can be measured by a method in which the resin discharged from the filter is taken out and directly measured, a method in which a sensor is installed inside the pipe of the filter outlet channel, or the like.
When a sensor is installed inside the pipe of the filter outlet channel, it is sometimes difficult to measure the correct resin temperature due to the influence of a heater installed outside the pipe around the sensor. If a device that discharges resin such as a die is installed near the filter outlet and the temperature of the resin discharged from the device can be regarded as equivalent to the resin temperature on the filter outlet side, The temperature of the discharged resin may be the resin temperature after filtration according to the present invention.
For the purpose of increasing the accuracy of the resin temperature after filtration, a sensor is installed inside the pipe of the filter outlet channel, and the temperature of the resin discharged from a die installed near the filter outlet is measured. Both methods can also be implemented.

  In the method of the present invention, the filter unit is usually provided with a heater composed of a plurality of blocks outside thereof to control the temperature. However, if the set temperature is too high, the polycarbonate resin may be deteriorated. Hereinafter, it is preferably set to 260 ° C. or less, particularly preferably 250 ° C. or less. On the other hand, if the set temperature is too low, the melt viscosity becomes high and it is difficult to filter with a filter, so that the temperature is usually 150 ° C. or higher, preferably 180 ° C. or higher, particularly preferably 200 ° C. or higher.

  Also, the piping for guiding the polycarbonate resin discharged from the filter unit to the die is usually provided with a heater outside, but if the set temperature is too high, the polycarbonate resin may be deteriorated. Hereinafter, it is preferably set to 260 ° C. or less, particularly preferably 250 ° C. or less. On the other hand, if the set temperature is too low, the melt viscosity becomes high and the pressure loss in the pipe increases, so that the temperature is usually 150 ° C. or higher, preferably 180 ° C. or higher, particularly preferably 200 ° C. or higher. Furthermore, if the residence time of the polycarbonate resin from the outlet of the filter unit to the die is long, the polycarbonate resin may be deteriorated. Therefore, the time is usually 1 to 30 minutes, preferably 3 to 20 minutes.

  In the method of the present invention, the temperature of the polycarbonate resin discharged from the die through filtration with the filter is preferably 200 ° C. or higher, preferably 220 ° C. or higher, more preferably 230 ° C. or higher. Is preferably less than 280 ° C, preferably less than 270 ° C, more preferably less than 265 ° C, and particularly preferably less than 260 ° C. If the temperature of the polycarbonate resin discharged from the die after filtration is too low, the melt viscosity becomes high and the extruded strands are not stable and may be difficult to pelletize with a rotary cutter or the like There is sex. On the other hand, if the temperature is too high, the polycarbonate resin is likely to be thermally deteriorated, which may cause a deterioration in hue, a decrease in molecular weight, and a decrease in mechanical strength associated therewith.

  The die is usually provided with a heater, but if the set temperature is too high, the polycarbonate resin may be deteriorated. Therefore, the die is usually set to 280 ° C. or less, preferably 260 ° C. or less, particularly preferably 250 ° C. or less. . On the other hand, if the set temperature is too low, the melt viscosity becomes high and the pressure loss in the pipe increases, so that the temperature is usually 150 ° C. or higher, preferably 180 ° C. or higher, particularly preferably 200 ° C. or higher.

  Normally, when polycarbonate resin is filtered through the above-mentioned filter having a small mesh opening, the temperature rises due to shearing heat generation, and when using an extruder, shearing heat generation due to screw rotation is also added, so the polycarbonate discharged from the die through filtration To control the temperature of the resin, it is important to comprehensively control the opening of the filter, the filtration area, the temperature setting, the molecular weight of the polycarbonate resin, the temperature setting of the filter unit, the temperature setting from the filter outlet to the die, etc. become. In addition, when using the extruder for supplying to the filter, it is important to select the processing amount of polycarbonate resin in the extruder, the rotational speed and peripheral speed of the screw, the element configuration, etc. as described above. become.

  In the method of the present invention, the difference between the temperature of the polycarbonate resin before being filtered by the filter and the temperature of the polycarbonate resin after the filtration is preferably within 50 ° C, more preferably within 30 ° C, most preferably Preferably it is within 10 degreeC. When the temperature difference between the temperature of the polycarbonate resin before being filtered by the filter and the temperature of the polycarbonate resin after the filtration becomes too large, particularly when a filter unit is constituted by a plurality of leaf disk filters, the resin supply side and The pressure balance may be lost on the discharge side, and the filter may be damaged.

In the method of the present invention, the terminal double bond of the polycarbonate resin obtained by polycondensation by the transesterification reaction before being supplied to the filter is filtered using the filter at X μeq / g. When the terminal double bond of the polycarbonate resin constituting the polycarbonate resin pellet obtained by discharging in the form of a strand and cooling using a cutter is Yμeq / g, the following formula (2) is preferably satisfied.
Y−X ≦ 10 (2)
More preferably, Y−X ≦ 8, and particularly preferably Y−X ≦ 5. When Y-X exceeds 10, not only tends to generate a colored component that is considered to be derived from the double bond, but also promotes gas generation in and around the filter, and strand discharge is unstable. Therefore, it may be difficult to pelletize with a cutter, which is not preferable.

  Y is preferably 50 μeq / g or less, more preferably 30 μeq / g, and particularly preferably 20 μeq / g. If Y is too large, the polycarbonate resin pellets may be colored.

In the method of the present invention, the reduced viscosity (ηsp / c) of the polycarbonate resin before being supplied to the filter is filtered using A, the filter, discharged from the die in the form of a strand, and cooled. Thereafter, when the reduced viscosity (ηsp / c) of the polycarbonate resin pellet obtained using a cutter is B, it is preferable to satisfy the following formula (3).
0.8 <B / A <1.1 (3)
More preferably, B / A> 0.85, still more preferably B / A> 0.9, and particularly preferably B / A> 0.95. When B / A is 0.8 or less, there is a tendency that a coloring component that is considered to be generated by a side reaction or a component that becomes a coloring precursor is generated. On the other hand, when the reduced viscosity increases in the polymer filter, the generation of foreign matters such as gels and burns rises, so it is preferable that B / A ≦ 1.0. A method for measuring the reduced viscosity will be described later.

When the extruder is installed between the polycondensation reactor and the filter, when the reduced viscosity (ηsp / c) of the polycarbonate resin supplied to the extruder is a, For B, it is preferable to satisfy the following formula (4).
0.8 <B / a <1.1 (4)
More preferably, B / a> 0.85, and particularly preferably B / a> 0.9. When B / a is 0.8 or less, there is a tendency that a colored component considered to be generated by a side reaction or a component that becomes a colored precursor is generated, which is not preferable. On the other hand, when the reduced viscosity increases, the generation of foreign matters such as gels and burns rises, so it is preferable that B / a ≦ 1.0.
In order to bring the change in the reduced viscosity in the polymer filter or extruder into the above range, the temperature of the polycarbonate resin in the final reactor, the temperature of the polycarbonate resin entering the polymer filter, the temperature of the polycarbonate resin discharged from the polymer filter, Selection of throughput and opening of the polymer filter per unit time, temperature control and residence time from the polymer filter to the die, when using an extruder, temperature of the polycarbonate resin supplied to the extruder, discharge from the extruder It is important to select the temperature, devolatilization pressure, water injection amount, water injection amount, screw rotation speed and peripheral speed, and element configuration of the polycarbonate resin to be used.

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

  In the present invention, in the case of stranding or pelletization in which the polycarbonate resin is in direct contact with the outside air, it is preferably class 7 as defined in JIS B 9920 (2002), more preferably, in order to prevent contamination by foreign matter from the outside air. It is desirable 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 desirable to use air from which foreign substances in the air have been removed in advance with a hepa filter or the like to prevent reattachment of foreign substances in the air. When using water cooling, it is desirable to use water from which metal in water has been removed with an ion exchange resin or the like, and further, foreign matter in water has been removed with the filter. The opening of the filter to be used is preferably 10 to 0.45 μm as a filtration accuracy of 99.9% removal.

  Further, in the present invention, a heat stabilizer, a neutralizing agent, an ultraviolet absorber, a release agent, a colorant, an antistatic agent, a lubricant, a lubricant, a plasticizer, a phase, which are generally known in the extruder. A solubilizer, a flame retardant, etc. can be added and kneaded.

(Filtration before polymerization)
On the other hand, in the method of the present invention, in order to further reduce foreign substances contained in the finally obtained polycarbonate resin pellets, it is also effective to pre-filter with a raw material filter before polycondensing the raw material monomers.

  The shape of the raw material filtration filter may be any type such as basket type, disc type, leaf disc type, tube type, flat cylindrical type, pleated cylindrical type, etc. A pleated type that can be taken is preferred. Further, the filter medium constituting the raw material filter may be any of metal wind, laminated metal mesh, metal nonwoven fabric, porous metal plate, etc., but from the viewpoint of filtration accuracy, a laminated metal mesh or metal nonwoven fabric is preferable, among which metal A type in which a nonwoven fabric is sintered and fixed is preferable.

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

  In addition, 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 filtration filter while ensuring the filtration performance, and in particular, the filter in the unit on the upstream side is preferably used. When the aperture is C μm and 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 this condition is satisfied, the raw material filtration filter is less likely to be blocked, and the replacement frequency of the raw material filtration filter can be reduced.

  The opening of the raw material filtration filter is not particularly limited, but in at least one of the raw material filtration filters, the filtration accuracy of 99.9% is preferably 10 μm or less, and the filter unit constituting the raw material filtration filter includes In the case of a plurality of arrangements, it is preferably 8 μm or more, more preferably 10 μm or more on the most upstream side, and preferably 2 μm or less, more preferably 1 μm or less on the most downstream side. In addition, the opening of the said raw material filtration filter said here is also determined based on ISO16889 mentioned above.

  In the present invention, the temperature of the raw material fluid when the raw material is passed through the raw material filtration 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. ° C, preferably 100 ° C to 150 ° C.

  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 the filter similar to the said raw material filtration filter.

(Polycarbonate resin obtained)
The yellow index value of the polycarbonate resin pellet obtained by the method of the present invention is preferably 70 or less, more preferably 30 or less, particularly preferably 15 or less, and most preferably 10 or less. In order to lower the yellow index value, as described above, it is necessary to appropriately select the monomer preparation conditions, the polymerization reaction conditions, the filtration conditions, and the extrusion conditions and screw elements when using an extruder.

  The reduced viscosity measured using an Ubbelohde viscometer at a concentration of 0.6 g / dL and a temperature of 20.0 ° C. ± 0.1 ° C. in methylene chloride using the polycarbonate resin pellet of the present invention is usually 0.3 dL / g. Or more, preferably 0.35 dL / g or more, more preferably 0.4 or more, and the upper limit of the reduced viscosity is usually 1.2 dL / g or less, preferably 0.8 dL / g or less, particularly preferably 0.7 dL. / G or less. If the reduced viscosity is too low, the mechanical strength of the molded product may be small.If the reduced viscosity is too large, not only will the flowability during molding decrease, the productivity and moldability will tend to decrease, but also filtration and Deterioration during extrusion may be severe.

The melt viscosity at a shear rate of 91.2 sec ⁻¹ measured at 240 ° C. using the polycarbonate resin pellets obtained by the method of the present invention is usually 500 Pa · s or higher, preferably 800 Pa · s or higher, particularly preferably 1000 Pa · s. The upper limit is usually 3000 Pa · s or less, preferably 2000 Pa · s or less. If the melt viscosity is too low, the mechanical strength of the molded product tends to be inferior. If it is too high, as described above, the shear heat generated by the filter or the extruder increases, and the deterioration during filtration or extrusion may become severe. There is. In addition, since the melt viscosity varies depending on the molecular structure in addition to the molecular weight, it is important to select these according to the required performance and control them within the above range.

The glass transition temperature when measured with a differential scanning calorimeter (DSC) using polycarbonate resin pellets obtained by the method of the present invention is usually 50 ° C. or higher, preferably 80 ° C. or higher, more preferably 90 ° C. or higher. . If the glass transition temperature is too low, the heat resistance is inferior, so the use as a molded product is limited. On the other hand, when the glass transition temperature is high, the melt viscosity at the time of filtration with a filter becomes too high, which may cause deterioration of the polycarbonate resin. Therefore, it is usually less than 160 ° C, preferably less than 145 ° C, more preferably less than 140 ° C. Particularly preferably, it is less than 130 ° C.
The glass transition temperature of the present invention means that the temperature is raised from room temperature to a temperature sufficiently exceeding the glass transition temperature at a heating rate of 20 ° C./min in a nitrogen stream, and after maintaining the temperature for 3 minutes, it is 20 ° C. to 30 ° C. Obtained by heating at a rate of 20 ° C./min to a temperature well above the glass transition temperature (obtained by the second temperature increase). This refers to the extrapolated glass transition start temperature obtained from DSC data.

  Further, the concentration of the terminal group represented by the following structural formula (9) of the polycarbonate resin constituting the polycarbonate resin pellet obtained in the present invention is preferably 20 μeq / g or more, more preferably 40 μeq / g or more, particularly preferably. It is 50 μeq / g or more. When the concentration of the terminal group is too low, coloring tends to increase during filtration. If it is too high, gas tends to be generated at the time of filtration, and there is a possibility of causing problems such as running out of gas in the strand. Therefore, it is preferably 200 μeq / g or less, more preferably 150 μeq / g or less, particularly preferably. 100 μeq / g or less.

  In order to control the concentration of the terminal group represented by the structural formula (9), in addition to controlling the molar ratio of the dihydroxy compound containing the dihydroxy compound of the present invention and the carbonic acid diester as a raw material, the polymerization pressure during the transesterification reaction And a method of controlling the polymerization temperature, the temperature of the reflux condenser, etc. according to the ease of volatilization of the monomer, among which the use of a reactor having a reflux condenser at the initial stage of polymerization stabilizes the concentration of the above end groups. It is effective for.

  In the transesterification reaction carried out in this invention, 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 represented by the general formula (7), It is inevitable that aromatic monohydroxy compounds such as substituted phenols are by-produced and remain in the polycarbonate resin. Since these may cause generation of gas during filtration and odor during molding, it is preferably less than 0.1% by weight, more preferably 0.05% by weight using an extruder with a vacuum vent. It is preferable to make it less than, especially less than 0.03% by weight. However, it is difficult to remove these compounds completely industrially, and the lower limit of the content of the aromatic monohydroxy compound is usually 0.0001% by weight.

  These aromatic monohydroxy compounds may naturally have a substituent depending on the raw material used, and may have, for example, an alkyl group having 5 or less carbon atoms. When diphenyl carbonate is used as the carbonic acid diester, the aromatic monohydroxy compound is phenol.

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

According to the method of the present invention, polycarbonate resin pellets with less coloring and less foreign matter can be obtained. Therefore, the foreign matter having a thickness of 25 μm or more contained in a 30 μm ± 5 μm-thick film formed from the resin is preferably 1000 / m ^2. Hereinafter, more preferably 500 pieces / m ² or less, and most preferably 200 pieces / m ² or less.

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

  ADVANTAGE OF THE INVENTION According to this invention, the polycarbonate resin pellet which is excellent in thermal stability, a hue, and mechanical strength, and there are few foreign materials can be provided.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited by a following example, unless the summary is exceeded. In the following, the physical properties and characteristics of polycarbonate were evaluated by the following methods.

(1) Measurement of oxygen concentration The oxygen concentration in the polymerization reaction apparatus was measured using an oxygen meter (AMI: 1000RS).

(2) Measurement of reduced viscosity Polycarbonate resin pellets were dissolved using methylene chloride as a solvent to prepare a polycarbonate solution having a concentration of 0.6 g / dL. Measured at a temperature of 20.0 ° C. ± 0.1 ° C. using an Ubbelohde viscometer manufactured by Moriyu Rika Kogyo Co., Ltd., and obtained a relative viscosity ηrel from the following equation from the solvent passage time t0 and the solution passage time t
ηrel = t / t0
From the relative viscosity, the specific viscosity ηsp was determined from the following formula.
ηsp = (ηrel−η0) / η0 = ηrel−1
The reduced viscosity ηsp / c was determined by dividing the specific viscosity by the concentration c (g / dL). The higher this value, the higher the molecular weight.

(3) Measurement of terminal phenyl group concentration and terminal double bond concentration About 30 mg of polycarbonate resin pellets are weighed and dissolved in about 0.7 mL of deuterated chloroform to make a solution, and 1,1,2,2-tetrabromoethane is contained inside. A known amount was added as a standard, and this was put into an NMR tube having an inner diameter of 5 mm, and a 1H NMR spectrum was measured at room temperature using JNM-AL400 (resonance frequency 400 MHz) manufactured by JEOL Ltd. It calculated | required from the signal intensity ratio based on a terminal double bond.
30 mg of polycarbonate was weighed and dissolved in about 0.7 mL of deuterated chloroform, and this was put into an NMR tube having an inner diameter of 5 mm, and a ¹ H NMR spectrum was measured. The amounts of terminal phenyl groups, terminal hydroxy groups, and terminal double bonds were determined from the intensity ratio of signals based on the structural units derived from each terminal group and each dihydroxy compound. The equipment and conditions used are as follows.
Device: JNM-AL400 (resonance frequency 400 MHz) manufactured by JEOL Ltd.
-Measurement temperature: normal temperature-Relaxation time: 6 seconds-Number of integrations: 512 times Analysis of ¹ H NMR in the case of a copolymer polycarbonate of ISB and CHDM exemplified in the present invention is performed as follows. Calculate the integrated value of the next peak.
(A): 5.6-4.8 ppm: derived from all ISB structural units (proton number: 3, molecular weight: 172.14)
(B): 2.2-0.5 ppm: derived from all CHDM structural units (proton number: 10, molecular weight: 170.21)
(C): 4.4 ppm: derived from ISB terminal hydroxy group (proton number: 1, molecular weight: 173.14)
(D): 3.6-3.5 ppm: derived from ISB terminal hydroxy group (proton number: 1, molecular weight: 173.14) and CHDM terminal hydroxy group (proton number: 2, molecular weight: 171.21)
(E): 3.5-3.4 ppm: derived from terminal hydroxyl group of CHDM (proton number: 2, molecular weight: 171.21) and derived from ISB terminal double bond (proton number: 1, molecular weight: 155.13)
(F): 2.6 ppm: derived from terminal hydroxyl group of ISB (proton number: 1, molecular weight: 173.14)
(G): 6.7-6.5 ppm: derived from terminal double bond of ISB (proton number: 1, molecular weight: 155.13)
(H) 2.3 ppm: derived from terminal double bond of CHDM (proton number: 2, molecular weight: 153.20)
(I): 7.5-7.3 ppm: derived from terminal phenyl group (proton number: 2, molecular weight: 93.10)
<Value corresponding to the number of moles of each structure>
All ISB structural units: (a) integral value / 3 = (a ′)
All CHDM structural units: (b) integral value / 10 = (b ′)
ISB terminal hydroxy group: (c) integral value + (f) integral value = (c ′)
CHDM terminal hydroxy group: {(d) integral value− (f) integral value} / 2 + {(e) integral value− (g) integral value)} / 2 = (d ′)
ISB terminal double bond: (g) integrated value = (e ′)
CHDM terminal double bond: (h) integral value / 2 = (f ′)
Terminal phenyl group: (i) integral value / 2 = (g ′)
<Amount of each end group (unit: μeq / g)>
ISB terminal hydroxy group amount: (c ′) / (i ′) × 1000000
-Terminal hydroxyl group amount of CHDM: (δ ') / (i') x 1000000
ISB terminal double bond amount: (e ′) / (i ′) × 1000000
CHDM terminal double bond amount: (f ′) / (i ′) × 1000000
-Terminal phenyl group amount: (g ') / (i') x 1000000
However, (i ′) = (a ′) × 172.14 + (b ′) × 170.21.

(4) Measurement of the glass transition temperature Using a differential scanning calorimeter (DSC 6220 manufactured by SII NanoTechnology Co., Ltd.), about 10 mg of polycarbonate resin pellets cut into an appropriate size are placed in the company's aluminum pan and sealed. The temperature was raised from room temperature to 250 ° C. at a heating rate of 20 ° C./min under a nitrogen stream of 50 mL / min. After maintaining the temperature for 3 minutes, it was cooled to 30 ° C. at a rate of 20 ° C./min. The temperature was maintained at 30 ° C. for 3 minutes, and the temperature was increased again to 200 ° C. at a rate of 20 ° C./min. From the DSC data obtained at the second temperature increase, the extrapolated glass transition start temperature was determined.

(5) Measurement of phenol content and DPC content in polycarbonate resin pellets About 1.25 g of a polycarbonate resin pellet sample is precisely weighed and dissolved in 7 ml of methylene chloride to prepare a solution, and then acetone is added so that the total amount becomes 25 ml. The reprecipitation process was performed by adding. Next, the treatment liquid was filtered through a 0.2 μm disk filter and quantified by liquid chromatography.

(6) Hue of polycarbonate resin pellets The obtained pellets are packed in a 1 cm cell, and the yellow index (YI) value in reflected light is measured three times using a color tester (CM-3700d manufactured by Konica Minolta), and the average value is calculated. Calculated. The smaller the YI value, the better the quality without yellowness.

(7) Quantitative determination of foreign matter The barrel set temperature of a 20 mm diameter single screw extruder equipped with a T die is 210 ° C, 220 ° C, 230 ° C, 230 ° C, 220 ° C from the pellet supply side, and polycarbonate resin pellets are melt extruded. A film having a thickness of 35 μm ± 5 μm was formed using a cooling roll, and the number of foreign matters of 25 μm or more per 1 m ² was measured using an optical control system (Film Quality Testing System (model FSA100)).

(8) Measurement of melt viscosity (Pa · s) A sample dried at 120 ° C. for 6 hours was heated to a constant temperature using a capillary rheometer (manufactured by Toyo Seiki Co., Ltd.) equipped with a die diameter of 1 mmφ × 10 mmL. measured between shear rate γ = 9.12~1824 ^{(sec -1)} Te was read melt viscosity at 91.2sec ^-1.

The abbreviations of the compounds used in the description of the following examples are as follows.
ISB: Isosorbide (Rocket Fleure, trade name POLYSORB)
-TCDDM: Tricyclodecane dimethanol (Oxea)
CHDM: 1,4-cyclohexanedimethanol (trade name SKY CHDM manufactured by Shin Nippon Rika Co., Ltd.)
・ DPC: Diphenyl carbonate (Mitsubishi Chemical Corporation)

[Example 1]
(First stage reaction)
In a polymerization reactor equipped with a heat medium jacket and a stirring blade using oil as a heat medium, a distillation pipe connected to a vacuum pump and a condenser, the molar ratio of ISB / TCDDM / DPC is 70/30/100. The cesium carbonate prepared in an aqueous solution was charged to 2.5 × 10 ⁻⁶ mol (converted to cesium metal atoms) per 1 mol of all dihydroxy compounds, and then sufficiently substituted with nitrogen (oxygen concentration 0.0005 vol% to 0.001 vol%). At this time, the DPC used was purified by distillation to have a chloride ion concentration of 10 ppb or less. Subsequently, a heated heat medium is circulated through the heat medium jacket of the reactor, and stirring is started when the reaction liquid (that is, the internal temperature) reaches 100 ° C., and the contents are kept while maintaining the internal temperature at 100 ° C. Thaw and homogenize. Thereafter, the temperature rise is started, the internal temperature is set to 220 ° C. in 40 minutes, the pressure reduction is started when the internal temperature reaches 220 ° C., and 13.3 kPa (absolute pressure, the same applies hereinafter) in 90 minutes. Was controlled as follows. When depressurization is started, the temperature of the oil introduced into the heat medium jacket (heat medium jacket inlet temperature) is appropriately adjusted so that the vapor of phenol generated by the reaction starts to distill and the internal temperature is controlled to be constant at 220 ° C. It was adjusted. During the time period when the amount of phenol distillate increased, the temperature of the heat medium oil was set at 242 ° C., and other time periods were set at less than 242 ° C.
After reaching 13.3 kPa, the pressure was maintained and maintained for an additional 60 minutes to obtain a polycarbonate oligomer. The phenol distilled at this stage was 94% of the theoretical distillation amount.

(Second stage reaction)
The polycarbonate oligomer obtained in the first stage was transferred to a polymerization reactor equipped with a heat medium jacket using oil as a heat medium, a stirring blade, and a distillation pipe connected to a vacuum pump under a nitrogen atmosphere. In the distillation pipe, a condenser using hot water (inlet temperature 45 ° C.) as a refrigerant and a cold trap using dry ice as a refrigerant were installed downstream of the condenser.
After transferring the oligomer, decompression was started, and the internal temperature was 220 ° C. and the pressure was 200 Pa in 60 minutes. Thereafter, the internal temperature was set to 230 ° C. over 20 minutes, the pressure was 133 Pa or less, the pressure was restored when the predetermined stirring power was reached, the contents were extracted in the form of strands, and pelletized with a rotary cutter.
The resulting pellet had a reduced viscosity of 0.362, a terminal phenyl group concentration of 66 μeq / g, a terminal double bond of 7.5 μeq / g, a YI of 25.4, a phenol content of 965 ppm, a DPC content of 19 ppm, The amount of foreign matter of 25 μm or more was 3035 / m ² .
A gear pump (EPG-28 / 20) manufactured by Nihon Daisnisco Co., Ltd. is disposed on the resin discharge side of a twin screw extruder manufactured by Nippon Steel Works (LABOTEX30HSS-32: L / D = 32) having two vent ports. A leaf disk filter (manufactured by Nippon Seisen Co., Ltd.) having a filtration accuracy of an outer diameter of 112 mm, an inner diameter of 38 mm, and 99% inside the containment container having an inner volume of 0.91 (L) downstream (made of stainless steel (material is stainless steel) A filter unit equipped with four SUS304 and SUS316)) was arranged. Before use, the filter was roasted at 310 ° C. for 40 hours in a water vapor atmosphere and then at 420 ° C. for 52 hours in an air atmosphere, cooled to room temperature, and then immersed in a 30% by weight nitric acid aqueous solution for 30 minutes. Then, an oxide film was formed, washed with water and dried.

The inlet side and the outlet side of the filter unit were set to be horizontal, and a die for forming a strand was attached to the outlet side of the filter unit. The kneading disk length (kneading element ratio) in the length of the elements constituting the entire screw of the extruder was 13.9%. Sensors for measuring the resin temperature are installed in the outlet channel of the extruder, the inlet channel of the filter unit, and the outlet channel of the filter unit. The barrel temperature of the extruder is set to 220 from the pellet supply side. C, 230 ° C, 230 ° C, 235 ° C, 240 ° C, 240 ° C, 240 ° C, 240 ° C, 240 ° C. The polycarbonate resin pellets obtained above were supplied to this at 10 kg / h, and at the same time, the screw rotation speed of the extruder was set to 100 rpm, and devolatilization was performed from a vent port using a vacuum pump. At this time, the pressure in the vent portion was 300 Pa or less in absolute pressure. The temperature of the polycarbonate resin discharged from the die through the filter unit was measured using a thermometer, and it was 257 ° C. The discharged polycarbonate resin was cooled with water in the form of a strand, solidified, and then rotated with a rotary cutter. Pelletized. The pellets had a reduced viscosity of 0.332, a YI of 59.6, a phenol content of 427 ppm, and a DPC content of 25 ppm. Further, the pellet was dried at 110 ° C. for 12 hours using a clean oven, a film was formed by the method described above, and the amount of foreign matter was measured. These results are shown in Table 1.
The kneading element ratio is a value calculated from the following equation.
Kneading element ratio (%) = (total length of kneading disc / total length of screw) × 100

[Example 2]
The same procedure as in Example 1 was performed except that the amount of resin supplied to the extruder was 15 kg / h and the screw rotation speed was 130 rpm. The temperature of the polycarbonate resin discharged from the die was 264 ° C., the reduced viscosity was 0.334, the YI of the pellet was 63.2, the phenol content was 476 ppm, and the DPC content was 27 ppm.

[Example 3]
The same procedure as in Example 1 was performed except that the amount of resin supplied to the extruder was 20 kg / h and the screw rotation speed was 150 rpm. The temperature of the polycarbonate resin discharged from the die was 269 ° C., the reduced viscosity was 0.328, the YI of the pellet was 65.6, the phenol content was 482 ppm, and the DPC content was 29 ppm.

[Example 4]
The same operation as in Example 1 was performed except that a leaf disk filter having a filtration accuracy of 99% of 40 μm was used. The YI of the pellet was 55.3, which was better than that of Example 1, but the amount of foreign matter slightly increased to 1710 / m ² .

[Comparative Example 1]
The extruder barrel temperature is set to 260 ° C, 270 ° C, 270 ° C, 275 ° C, 280 ° C, 280 ° C, 280 ° C, 280 ° C, 280 ° C from the pellet supply side, and the screw speed of the extruder is set to The same operation as in Example 1 was performed except that the rpm was 250 rpm. The temperature of the polycarbonate resin discharged from the die was 282 ° C., and the reduced viscosity decreased to 0.275. Moreover, YI of the pellet deteriorated to 81.1.

[Example 5]
In the raw material preparation tank sufficiently substituted with nitrogen (oxygen concentration 0.0005 vol% to 0.001 vol%), the raw material prepared so that the ISB / CHDM / DPC molar ratio is 50/50/100 is used as the heat medium. To the first polymerization reactor equipped with a heat medium jacket, a heat medium internal coil, a stirring blade, a distillation pipe connected to a vacuum pump and a condenser, and at the same time, a raw material supply pipe From the connected catalyst supply pipe, calcium acetate monohydrate in an aqueous solution was continuously supplied so as to be 1.25 × 10 ⁻⁶ mol (calcium metal atom equivalent) per 1 mol of all dihydroxy compounds. After mixing the raw material and catalyst aqueous solution by piping, install two pleated cylindrical type raw material filtration filters in the flow path to enter the first reactor, the upstream raw material filtration filter opening is 10 μm, downstream The mesh opening was 1 μm. In the first polymerization reactor, the distillation pipe is provided with a reflux condenser using oil (inlet temperature 130 ° C.) as a refrigerant, and phenol and the like that are not condensed in the reflux condenser. In addition, a condenser using warm water (inlet temperature 45 ° C.) as a refrigerant was disposed. While keeping the rotation speed of the stirring blade of the first polymerization reactor constant, the internal temperature is controlled to be constant at 185 ° C., the pressure is 25 kPa, and the residence time is 1.5 hours, and the reaction solution is continuously extracted from the bottom of the reaction tank. To the second polymerization reactor. Similar to the first polymerization reactor, the second polymerization reactor includes a heat medium jacket, a heat medium internal coil, a stirring blade, a distillation pipe connected to a vacuum pump, and a distillation pipe having a reflux condenser and a condenser. The inner temperature was 213 ° C., the pressure was 14 kPa, and the residence time was controlled to be constant at 1 hour, and the reaction solution was continuously withdrawn from the bottom of the reaction vessel and supplied to the third polymerization reactor. The third polymerization reactor is controlled so as to be constant at an internal temperature of 229 ° C., a pressure of 6 kPa, and a residence time of 1 hour. The polycondensation reaction proceeds while distilling off the by-produced phenol, and the reaction solution is transferred to the reaction vessel. It was continuously extracted from the bottom and supplied to a horizontal stirring reactor (fourth polymerization reactor) having two horizontal rotating shafts and mutually discontinuous stirring blades mounted substantially perpendicular to the horizontal shaft. The fourth polymerization reactor was controlled so that the internal temperature near the inlet was 228 ° C., the internal temperature near the outlet was 240 ° C., the pressure was 0.07 kPa, and the residence time was 2 hours, and the polycondensation reaction was further advanced. . The obtained polycarbonate resin has an additive supply port and three vent ports, L / D = 42, and the kneading disk occupies 6% of the length of the elements constituting the entire screw of the extruder. Continuously fed to the twin screw extruder. In the extruder, 0.1% of water was supplied to the polycarbonate resin to be treated, and the vent port was connected to a vacuum pump to remove volatile components contained in the polycarbonate resin. The barrel temperature of the extruder was set to 245 ° C. for the 4 blocks upstream, 225 ° C. for the 6 blocks downstream, and the screw rotation speed was 250 rotations. At this time, the polycarbonate resin supplied to the extruder was temporarily extracted, and temperature measurement and various analyzes were performed. The results are shown in Table 2.

  The polycarbonate resin processed by the extruder was supplied to a filter unit having a resin inlet at the bottom and an outlet at the top through a gear pump installed at the outlet. Table 2 shows the temperature of the resin sampled before the filter unit and various measured values. A leaf disk filter (manufactured by Nippon Pole Co., Ltd.) having a mesh size of 7 μm was mounted inside the filter unit to remove foreign substances in the polycarbonate resin. Before use, the filter was roasted at 310 ° C. for 40 hours in a water vapor atmosphere and then at 420 ° C. for 52 hours in an air atmosphere, cooled to room temperature, and then immersed in a 30% by weight nitric acid aqueous solution for 30 minutes. Then, an oxide film was formed, washed and dried. The filter unit was provided with a heater composed of a plurality of blocks, and each temperature was set to 230 to 240 ° C. On the outlet side of the filter unit, a die was installed through a polymer pipe equipped with a heater composed of a plurality of blocks. The outlet resin temperature of the filter and the outlet resin temperature of the die were measured in the same manner as in Example 1. The polycarbonate resin was extracted in the form of a strand in a room maintained at a class 10000 cleanness from the die, solidified in a water tank, and pelletized with a rotary cutter. The analytical values are shown in Table 2.

[Example 6]
The internal temperature of the first polymerization reactor is 194 ° C., the pressure is 27 kPa, the internal temperature of the second polymerization reactor is 190 ° C., the pressure is 19 kPa, the internal temperature of the third polymerization reactor is 213 ° C., the pressure is 7.5 kPa, The same procedure as in Example 1 was performed except that the inner temperature near the inlet of the fourth polymerization reactor was 214 ° C., the inner temperature near the outlet was 228 ° C., the pressure was 0.7 kPa, and the die heater was set to 230 ° C. It was.

[Example 7]
The internal temperature of the first polymerization reactor is 190 ° C., the pressure is 25 kPa, the internal temperature of the second polymerization reactor is 196 ° C., the pressure is 17.7 kPa, the internal temperature of the third polymerization reactor is 215 ° C., and the pressure is 6. 9 kPa, the internal temperature near the inlet of the fourth polymerization reactor is 218 ° C., the internal temperature near the outlet is 232 ° C., the pressure is 0.9 kPa, the barrel temperature of the extruder is set to 240 ° C. for the upstream 4 blocks, and the downstream The same procedure as in Example 1 was conducted except that the above 6 blocks were changed to 185 ° C.

[Example 8]
In the raw material preparation tank, the molar ratio of ISB / CHDM / DPC is adjusted to 70/30/100, the internal temperature of the first polymerization reactor is 188 ° C., the pressure is 24.2 kPa, and the second polymerization reactor The internal temperature was 194 ° C., the pressure was 19.9 kPa, the internal temperature of the third polymerization reactor was 214 ° C., the pressure was 9.9 kPa, the internal temperature near the inlet of the fourth polymerization reactor was 218 ° C., and the internal temperature near the outlet Was 232 ° C., the pressure was 0.1 kPa, the barrel temperature of the extruder was set in the same manner as in Example 1 except that the upstream 4 blocks were 240 ° C. and the downstream 6 blocks were 195 ° C.

[Example 9]
The same operation as in Example 6 was performed except that the aperture of the filter was changed to 22 μm. The pressure loss in the polymer filter was reduced, the decrease in molecular weight and the increase in the number of double bond ends tended to be suppressed, the pellet color was improved, but the amount of foreign matter increased.

[Example 10]
The same operation as in Example 9 was performed except that the total length of the kneading disk of the extruder was 12% of the total length of the screw.

[Comparative Example 2]
The internal temperature of the third polymerization reactor is 240 ° C., the pressure is 4 kPa, the internal temperature near the inlet of the fourth polymerization reactor is 240 ° C., the internal temperature near the outlet is 252 ° C., the pressure is 0.02 kPa, and the barrel temperature of the extruder The upstream 4 blocks are 250 ° C, the downstream 6 blocks are 260 ° C, the screw speed is 280rpm, the filter unit heater set temperature is 270-280 ° C, the polymer pipe heater set temperature is 270-280 ° C The same procedure as in Example 1 was performed except that the die heater was set at 280 ° C. Although the pressure loss in the polymer filter tended to be suppressed, the temperature of the polycarbonate resin discharged from the die was 285 ° C., and it was remarkably colored. Further, gas was generated from the die, the strands were disturbed, and pellets could not be obtained.

1a Raw material (carbonic acid diester) supply port 1b, 1c Raw material (dihydroxy compound) supply port 1d Catalyst supply port 2a Raw material mixing tank 3a Anchor type stirring blade 4a Raw material mixed liquid transfer pump 4b, 4c, 4d Gear pump 5a Raw material filtration filter 6a First Vertical stirring reaction tank 6b Second vertical stirring reaction tank 6c Third vertical stirring reaction tank 6d Fourth horizontal stirring reaction tank 7a, 7b, 7c Max blend blade 7d Biaxial glasses stirring blade 8a, 8b Internal heat exchanger 9a, 9b Reflux coolers 10a, 10b Reflux tubes 11a, 11b, 11c, 11d Distillate tubes 12a, 12b, 12c, 12d Condensers 13a, 13b, 13c, 13d Decompressor 14a Distillate recovery tank 15a Extruder 15b ( Polymer) Filter 15c Die 16a Strand cooling tank 16b Strand cutter 16c Air blower 6d product hopper 16e meter 16f product bag (paper bag, such as a flexible container)

Claims (23)

A polycarbonate resin obtained by polycondensation of a dihydroxy compound and a carbonic acid diester is filtered using a filter and then cooled and solidified.
The dihydroxy compound contains at least a dihydroxy compound having a site represented by the following general formula (1) in a part of the structure, the opening of the filter is 50 μm or less, and the polycarbonate resin after filtration using the filter The polycarbonate resin is filtered so that the temperature of the resin becomes 200 ° C. or higher and lower than 280 ° C.

(However, the site represented by the above general formula (1) unless it is part of _-CH 2 -O-H.)   The method for producing a polycarbonate resin according to claim 1, wherein the polycarbonate resin obtained by the polycondensation is supplied to the filter and filtered in a molten state without solidifying. The terminal double bond before being supplied to the filter of the polycarbonate resin is Xμeq / g,
When the terminal double bond of the polycarbonate resin obtained by cooling and solidifying is Yμeq / g,
The manufacturing method of the polycarbonate resin of Claim 1 or 2 which satisfy | fills following formula (2).
Y−X ≦ 10 (2) The reduced viscosity (ηsp / c) of the polycarbonate resin before being supplied to the filter is A,
When the reduced viscosity (ηsp / c) of the polycarbonate resin obtained by cooling and solidifying is B,
The manufacturing method of the polycarbonate resin of any one of Claims 1 thru | or 3 which satisfy | fills following formula (3).
0.8 <B / A <1.1 (3) 5. The melt viscosity at a shear rate of 91.2 sec ⁻¹ measured at 240 ° C. using the polycarbonate resin obtained by cooling and solidifying is 500 Pa · s or more and 3000 Pa · s or less. The manufacturing method of polycarbonate resin as described in claim | item.   The polycarbonate resin according to any one of claims 1 to 5, wherein a glass transition temperature when measured with a differential scanning calorimeter is 50 ° C or higher and lower than 160 ° C using the polycarbonate resin obtained by cooling and solidifying. Manufacturing method.   Using the polycarbonate resin obtained by cooling and solidification, the reduced viscosity (ηsp / c) measured at a concentration of 0.6 g / dL and a temperature of 20.0 ° C. ± 0.1 ° C. in methylene chloride was 0.3 dL / The method for producing a polycarbonate resin according to any one of claims 1 to 6, wherein the production method is g or more and 1.2 dL / g or less. The filter is stored in a container, and a value obtained by dividing the internal volume (m ³ ) of the storage container by the flow rate (m ³ / min) of the polycarbonate resin to be filtered is 2 to 10 minutes. The manufacturing method of the polycarbonate resin of any one of thru | or 7.   The polycarbonate according to any one of claims 1 to 8, wherein the content of the aromatic monohydroxy compound contained in the polycarbonate resin obtained by cooling and solidifying is 0.0001 wt% or more and less than 0.1 wt%. Manufacturing method of resin.   The method for producing a polycarbonate resin according to any one of claims 1 to 9, wherein the raw material monomer is filtered through a raw material filter before the polycondensation reaction.   The method for producing a polycarbonate resin according to any one of claims 1 to 10, wherein the filter is made of a metal that has been previously baked at a temperature of 350 ° C or higher and 500 ° C or lower.   The polycarbonate resin production according to any one of claims 1 to 11, wherein the polycarbonate resin before filtration is supplied from a lower part of a containment container of the filter, and the polycarbonate resin after filtration is discharged from an upper part of the containment container. Method. The polycondensation is performed using a catalyst;
The method for producing a polycarbonate resin according to any one of claims 1 to 12, wherein the catalyst is at least one metal compound selected from the group consisting of a metal of Group 2 of the long-period periodic table and lithium.   The method for producing a polycarbonate resin according to any one of claims 1 to 13, wherein the dihydroxy compound having a site represented by the general formula (1) in a part of the structure is isosorbide.   The polycarbonate resin obtained by the polycondensation is subjected to an operation of devolatilizing with an extruder having a biaxial shaft having a vent port, and then supplied to the filter. Of producing a polycarbonate resin.   The screw of the extruder is composed of a plurality of elements, at least one of the elements is a kneading disk, and the total length of the kneading disk is 20% or less of the total length of the screw. The method for producing a polycarbonate resin according to claim 15.   The method for producing a polycarbonate resin according to claim 15 or 16, wherein the temperature of the polycarbonate resin supplied to the extruder is 200 ° C or higher and lower than 250 ° C.   18. The method for producing a polycarbonate resin according to claim 15, wherein the temperature of the polycarbonate resin supplied to the filter is 220 ° C. or higher and lower than 280 ° C. 18. The reduced viscosity (ηsp / c) of the polycarbonate resin supplied to the extruder is a,
When the reduced viscosity (ηsp / c) of the polycarbonate resin obtained by cooling and solidifying is B,
The method for producing a polycarbonate resin according to any one of claims 15 to 18, wherein the following formula (4) is satisfied.
0.8 <B / a <1.1 (4)   The method for producing a polycarbonate resin according to any one of claims 15 to 19, wherein a gear pump is disposed between the extruder and the filter.   A polycarbonate resin having a yellow index value of 30 or less obtained by the production method according to any one of claims 1 to 20. A polycarbonate resin obtained by the production method according to any one of claims 1 to 20, or a film having a thickness of 20 µm to 200 µm obtained by extrusion molding of the polycarbonate resin according to claim 21, A polycarbonate resin film having a maximum length of 25 μm or more contained in the film of 1000 / m ² or less. Using the catalyst and dihydroxy compound and carbonic acid diester as raw material monomers, polycondensation by transesterification reaction, the obtained polycarbonate resin is filtered using a filter, discharged from the die in the form of a strand, after cooling, A method for producing polycarbonate resin pellets using a cutter,
The dihydroxy compound includes at least a dihydroxy compound having a site represented by the following general formula (1) in a part of the structure;
A method for producing polycarbonate resin pellets, wherein the filter has an opening of 50 μm or less, and the temperature of the resin discharged from the die is 200 ° C. or more and less than 280 ° C.

(However, the site represented by the above general formula (1) unless it is part of _-CH 2 -O-H.)

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