JP2014114442A - Method for producing polycarbonate resin pellets - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method that can efficiently and stably produce polycarbonate resin which is excellent in heat stability, color tone and mechanical strength, and which has less foreign matter.SOLUTION: The polycarbonate resin pellets are produced by using, as dihydroxy compound of the raw material, a particular dihydroxy compound that has a -CH-O- group, carrying out the polycondensation by an ester exchange reaction, and feeding thus obtained polycarbonate resin that has a glass transition temperature of 80°C or more and lower than 145°C, into an extruder at temperature of 180°C or more and lower than 250°C.

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).

  Before making polycarbonate resin pellets, add or disperse a catalyst deactivator to stop the progress of polymerization, remove residual monomers and other volatile components under reduced pressure, heat stabilizers, release agents, etc. It is required to add and / or disperse the additive in order to impart performance according to the intended use, and in the conventional polycarbonate resin containing bisphenol A as a monomer component, an extruder is used. It has been proposed to use these operations. (For example, refer to Patent Document 7).

International Publication No. 04/111106 Pamphlet Japanese Patent Laid-Open No. 2006-232897 JP 2006-28441 A JP 2008-24919 A JP 2009-91404 A JP 2009-91417 A JP-A-5-239333

  However, since polycarbonate resins containing special dihydroxy compounds other than bisphenols as monomer components start to decompose at a lower temperature than conventional polycarbonate resins containing bisphenols as monomer components, low molecular weight components can be removed or additives In order to mix, if it is supplied to the extruder under the same temperature conditions as before, there is a possibility that the outgassing of the strand may occur due to the decomposition gas generated in the filter in the filtration process by the filter, and the production may become unstable. is there.

  On the other hand, if the melt viscosity of the polycarbonate resin is to be lowered, the by-product monohydroxy compound tends to remain, and it may be difficult to reduce the by-product monohydroxy compound from the polycarbonate resin.

  An object of the present invention is to eliminate the above-mentioned conventional problems, to obtain polycarbonate resin pellets that can stably produce polycarbonate resin pellets and reduce the residual amount of by-product monohydroxy compounds.

  As a result of intensive studies to solve the above-mentioned problems, the present inventor obtained polycondensation by a transesterification reaction using a catalyst, a specific dihydroxy compound and a carbonic acid diester as a raw material monomer, and obtained polycarbonate resin. In the method of producing pellets, the polycarbonate resin pellets can be stably produced by using a specific polycarbonate resin under a specific temperature condition and / or an extruder equipped with a rotor having a specific screw. And it discovered that the polycarbonate resin pellet which reduced the residual amount of the by-product monohydroxy compound could be obtained.

That is, the gist of the present invention resides in the following [1] to [12].
[1] A method for producing a polycarbonate resin pellet by polycondensation by a transesterification reaction using a catalyst and a dihydroxy compound and a carbonic acid diester as raw materials, and supplying the obtained polycarbonate resin to an extruder, The screw of the extruder includes a rotor, the dihydroxy compound includes at least a specific dihydroxy compound having a site represented by the following general formula (1) in a part of the structure, and the screw of the extruder includes a plurality of pieces. The kneading disc is at least one piece, and the total length of the kneading disc used for the screw of the extruder is 3 to 15% of the total length of the screw. Method for producing polycarbonate resin pellets, characterized in that

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

[2] A method of producing a polycarbonate resin pellet by polycondensation by a transesterification reaction using a catalyst, a dihydroxy compound and a carbonic acid diester as raw material monomers, and supplying the obtained polycarbonate resin to an extruder, The screw of the extruder includes a rotor, and the dihydroxy compound includes at least a specific dihydroxy compound having a site represented by the following general formula (1) in a part of the structure, and the polycarbonate resin discharged from the extruder The manufacturing method of the polycarbonate resin pellet characterized by the temperature being 265 degrees C or less.

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

[3] The method for producing polycarbonate resin pellets according to [1] or [2], wherein the polycarbonate resin obtained by polycondensation by transesterification is supplied to the extruder in a molten state.
[4] The screw of the extruder is composed of a plurality of elements, at least one of the elements is a rotor, and the total length of the rotor is 10 to 30% of the total length of the screw. The method for producing a polycarbonate resin pellet according to any one of [1] to [3].

[5] The screw of the extruder is composed of a plurality of pieces of elements, and at least one piece of the elements is a kneading disc, and the number of pieces of the kneading disc is 10 or less. The method for producing polycarbonate resin pellets according to any one of [1] to [3].
[6] The method for producing a polycarbonate resin pellet according to any one of [1] to [5], wherein the glass transition temperature of the polycarbonate resin is 90 ° C. or higher and lower than 160 ° C.

[7] The method for producing a polycarbonate resin pellet according to any one of [1] to [6], wherein the content of the monohydroxy compound contained in the polycarbonate resin pellet is less than 0.1 wt%.
[8] The method for producing a polycarbonate resin pellet according to any one of [1] to [7], wherein the raw material monomer is filtered with a raw material filtration filter before polycondensation.

[9] The method for producing a polycarbonate resin pellet according to any one of [1] to [8], wherein an operation of kneading a heat stabilizer is performed using the extruder.
[10] The polycarbonate resin according to any one of [1] to [9], 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. Pellet manufacturing method.
[11] Any one of [1] to [10], wherein the specific dihydroxy compound is at least one dihydroxy compound selected from the dihydroxy compound represented by the following general formula (2) and the following general formula (10): The manufacturing method of the polycarbonate resin pellet of description.

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

  ADVANTAGE OF THE INVENTION According to this invention, the polycarbonate resin pellet which can manufacture a polycarbonate resin pellet stably and reduced the residual amount of the byproduct monohydroxy compound can be obtained. As a result, it is excellent in mechanical strength and hue, and has few foreign substances, such as electrical and electronic parts, automobile parts and other injection molding fields, films, sheet fields, bottles, container fields, camera lenses, viewfinder lenses, CCDs, etc. Fix lenses such as lenses for CMOS, retardation films used for liquid crystal 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 obtain polycarbonate resin pellets having performance applicable to a wide range of fields such as binder applications.

Process drawing showing an example of a manufacturing process according to the present invention Photograph showing an example of a rotor Photograph showing an example of Nijo full flight Photo showing an example of a kneading disc Photograph showing an example of Nijo type

  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 polycarbonate resin pellets of the present invention comprises polycondensation by a transesterification reaction using a catalyst, a dihydroxy compound and a carbonic acid diester as raw material monomers, and the resulting polycarbonate resin is supplied to an extruder to obtain polycarbonate resin pellets. More specifically, the screw of the extruder is composed of a plurality of pieces of elements, and at least one piece of the elements is a kneading disk, and is used for the screw of the extruder. The total length of the kneading disc is 3 to 15% of the total length of the screw (this is referred to as the first aspect of the present invention), or the screw of the extruder is provided with a rotor. The dihydroxy compound is represented by the following general formula (1) as part of the structure. At least a specific dihydroxy compound having a position, and the temperature of the polycarbonate resin discharged from the extruder is 265 ° C. or less (this is referred to as the second aspect of the present invention), It solves the problem.

However, unless moiety represented by the above general formula (1) 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, compounds having an aromatic group in the side chain and an ether group bonded to the aromatic group in the main chain, the following general Anhydrosugar alcohol typified by the dihydroxy compound represented by the formula (2), a compound having a cyclic ether structure such as spiroglycol represented by the following general formula (3), at least represented by the following general formula (10) Specific dihydroxy compounds that are dihydroxy compounds having a fluorene moiety, etc. Among them, diethylene glycol, triethylene glycol, and polyethylene glycol are preferable from the viewpoint of easy availability, handling, reactivity at the time of polymerization, and hue of the obtained polycarbonate resin. An anhydrous sugar alcohol represented by the dihydroxy compound represented by the formula (2), a compound having a cyclic ether structure represented by the following general formula (3), and at least a fluorene moiety represented by the following general formula (10) A dihydroxy compound is preferable, and among them, at least one dihydroxy compound selected from the dihydroxy compound represented by the following general formula (2) and the following general formula (10) is more 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.

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

  Examples of the dihydroxy compound represented by the general formula (2) include isosorbide, isomannide, and isoidet, which have a stereoisomeric relationship, and these may be used alone or in combination of two or more. You may use it in combination.

  Examples of the dihydroxy compound having at least a fluorene moiety represented by the general formula (10) include 9,9-bis (4- (2-hydroxyethoxy) phenyl) fluorene and 9,9-bis (4-hydroxy-). 2-methylphenyl) fluorene, 9,9-bis (4- (2-hydroxyethoxy-2-methyl) phenyl) fluorene, 9,9-bis (4-hydroxyphenyl) 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-butylpheny ) Fluorene, 9,9-bis (4- (2-hydroxyethoxy) -3-cyclohexylphenyl) fluorene, 9,9-bis (4- (2-hydroxyethoxy) -3-phenylphenyl) fluorene, 9,9 -Bis (4- (2-hydroxyethoxy) -3,5-dimethylphenyl) fluorene, 9,9-bis (4- (2-hydroxyethoxy) -3-tert-butyl-6-methylphenyl) fluorene, 9 , 9-bis (4- (3-hydroxy-2,2-dimethylpropoxy) phenyl) fluorene and the like, and these may be used alone or in combination of two or more.

  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, And aromatic bisphenols such as 3′-dichlorodiphenyl ether.

  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.

  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 80 mol% or less, 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 (4). These carbonic acid diesters may be used alone or in combination of two or more.

A ¹ and A ² are a substituted or unsubstituted aliphatic group having 1 to 18 carbon atoms or a substituted or unsubstituted aromatic group, and A ¹ and A ² may be the same or different.

  Examples of the carbonic acid diester represented by the general formula (4) 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 increases, the rate of transesterification may decrease, and it may be difficult to produce a polycarbonate having a desired molecular weight. 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”).

  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.

  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 Compound is more preferable.

  In addition, a basic compound such as a basic boron compound, a basic phosphorus compound, a basic ammonium compound, and an amine compound can be used in combination with the aforementioned Group 1 metal compound and / or Group 2 metal compound. However, it is particularly preferred to use only Group 1 metal compounds and / or Group 2 metal compounds.

  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, per 1 mol of all dihydroxy compounds used. 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. Moreover, as an upper limit, it is 50 micromol normally, Preferably it is 30 micromol, More preferably, it is 20 micromol.

  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 sodium 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. 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. 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 130 ° 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. The reason for carrying out the polymerization in a plurality of reactors in the present invention is that, in the initial stage of the polymerization reaction, since there are many monomers contained in the reaction solution, the volatilization of the monomers can be suppressed while maintaining the necessary polymerization rate. It is important that, in the latter stage of the polymerization reaction, it is important to sufficiently distill off the by-product monohydroxy compound in order to shift the equilibrium to the polymerization side, and desirable polymerization reaction conditions are different in the early and late stages. . 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, 0.1 to 10 hours, preferably 1 to 6 hours, particularly preferably For 0.5-3 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.

  From the viewpoint of effective utilization of resources, the monohydroxy compound distilled off as a by-product in the reaction is preferably reused as a raw material for diphenyl carbonate, bisphenol A, etc. after purification as necessary.

(Process after polycondensation reaction)
The polycarbonate resin of the present invention is a polycarbonate obtained by polycondensation in order to carry out the removal of low molecular weight components contained in the polycarbonate resin, the addition kneading of a heat stabilizer and the like after the polycondensation reaction described above. Resin is introduced into the extruder. Preferably, the polycarbonate resin discharged from the extruder is then filtered using a filter.

As a method of supplying the polycarbonate resin obtained by polycondensation as described above to an extruder and obtaining pellets, for example, the following method may be mentioned.
1) Polycarbonate resin is supplied from a final polymerization reactor to a uniaxial or biaxial extruder in a molten state, and after melt extrusion, operations such as filtration through a filter are performed as necessary, and then solidified by cooling in the form of a strand. Let it be pelletized with a rotary cutter,
2) 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, and once cooled and solidified in the form of strands, pelletized. For example, a method of introducing again into an extruder and performing an operation such as filtering with a filter as necessary, cooling and solidifying in the form of a strand, and pelletizing.

  Above all, in order to minimize heat history and suppress thermal degradation such as deterioration of hue and molecular weight, polycarbonate resin is fed into a uniaxial or biaxial extruder in a molten state without solidifying from the final polymerization reactor. Is preferably directly filtered through the filter, discharged from a die, cooled and solidified in the form of a strand, and pelletized with a rotary cutter or the like.

<Example of manufacturing equipment>
An example of an apparatus for carrying out the present invention for obtaining polycarbonate resin pellets from the raw material monomers described above is shown in the process diagram of FIG. It is assumed that isosorbide (ISB) is used as the dihydroxy compound of the present invention which is a raw material monomer, diphenyl carbonate (DPC) is used as a carbonic acid diester, and calcium acetate is used as a polymerization catalyst.

  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 reactor 6a via the raw material supply pump 4a and the raw material filtration filter 5a. Moreover, calcium acetate aqueous solution is continuously supplied as a raw material catalyst from the catalyst supply port 1d in the middle of the transfer piping of the raw material mixed melt.

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

  The first vertical stirring reactor 6a, the second vertical stirring reactor 6b, and the third vertical stirring reactor 6c are provided with Max Blend blades 7a, 7b, 7c, respectively. The fourth horizontal stirring reactor 6d is provided with a biaxial glasses-type stirring blade 7d. A gear pump 4b is provided after the third vertical stirring reactor 6c because the transferred reaction liquid has a high viscosity.

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

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

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

  In 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. Further, a cold trap (not shown) is connected to the downstream side of the condensers 12c and 12d attached to the third vertical stirring reactor 6c and the fourth horizontal stirring reactor 6d, respectively. Is continuously solidified and recovered.

  The reaction liquid raised to a predetermined molecular weight is withdrawn from the fourth horizontal stirring reactor 6d and transferred to the 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 as long as the screw of the extruder has a rotor, but a single or twin screw 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. The length of the entire screw is L / D (ratio between the effective length of the screw and the screw diameter), which is 15 or more and less than 100, preferably 20 or more and less than 60. When it is less than 15, kneading and devolatilization are not sufficiently performed, and when it is 100 or more, the resin deteriorates due to shearing heat generation, and there is a risk of molecular weight reduction or coloring.
Usually known in this extruder, heat stabilizer, neutralizer, UV absorber, mold release agent, colorant, antistatic agent, lubricant, lubricant, plasticizer, compatibilizer, flame retardant, etc. Can be added and kneaded.

  Examples of the heat stabilizer include triphenyl phosphite, tris (nonylphenyl) phosphite, tris (2,4-di-tert-butylphenyl) phosphite, tridecyl phosphite, trioctyl phosphite, trioctadecyl phosphite, Didecyl monophenyl phosphite, dioctyl monophenyl phosphite, diisopropyl monophenyl phosphite, monobutyl diphenyl phosphite, monodecyl diphenyl phosphite, monooctyl diphenyl phosphite, bis (2,6-di-tert-butyl-4 -Methylphenyl) pentaerythritol diphosphite, 2,2-methylenebis (4,6-di-tert-butylphenyl) octyl phosphite, bis (nonylphenyl) pentaerythritol diphosphite Phosphite-based thermal stabilizers such as bis (2,4-di-tert-butylphenyl) pentaerythritol diphosphite, distearyl pentaerythritol diphosphite, pentaerythritol tetrakis (3-mercaptopropionate), pentaerythritol tetrakis (3-lauryl thiopropionate), glycerol-3-stearyl thiopropionate, triethylene glycol-bis [3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate], 1,6 -Hexanediol-bis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], pentaerythritol-tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) Propionate] Octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-blu-4- Hydroxybenzyl) benzene, N, N-hexamethylenebis (3,5-di-tert-butyl-4-hydroxy-hydrocinnamide), 3,5-di-tert-butyl-4-hydroxy-benzylphosphonate-diethyl Ester, tris (3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate, 4,4′-biphenylenediphosphinic acid tetrakis (2,4-di-tert-butylphenyl), 3,9-bis { 1,1-dimethyl-2- [β- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy Hindered phenol thermal stabilizers such as ethyl} -2,4,8,10-tetraoxaspiro (5,5) undecane, dilauryl-3,3′-thiodipropionic acid ester, ditridecyl-3,3′- Thiodipropionate, dimyristyl-3,3′-thiodipropionate, distearyl-3,3′-thiodipropionate, laurylstearyl-3,3′-thiodipropionate, pentaerythritol tetrakis (3-laurylthiopropionate), bis [2-methyl-4- (3-laurylthiopropionyloxy) -5-tert-butylphenyl] sulfide, octadecyl disulfide, mercaptobenzimidazole, 2-mercapto-6-methyl Benzimidazole, 1,1′-thiobis (2-na Other sulfur-based heat stabilizers Torr) such as, may also be used hindered amine thermal stabilizers, which are used alone or in combination.

Examples of phosphite heat stabilizers include trisnonylphenyl phosphite, trimethyl phosphate, tris (2,4-di-tert-butylphenyl) phosphite, bis (2,4-di-tert-butylphenyl) pentaerythritol di- Phosphite, bis (2,6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphite is preferably used. These compounds can be used alone or in combination of two or more. Here, the content of the phosphite heat stabilizer is 0.0001 part by weight or more and 1 part by weight or less, preferably 0.001 part by weight or more and 0.1 part by weight, based on 100 parts by weight of the polycarbonate resin (a). Hereinafter, it is more preferably 0.003 parts by weight or more and 0.01 parts by weight or less.
When the content is excessively small, the coloring suppression effect may be insufficient. In addition, if the content is excessively large, deposits increase on the surface of the cooling roll in the case of a mold surface or film molding, and the appearance of the surface of the product may be impaired. May be reduced.

  As the hindered phenol-based heat stabilizer, a compound having an aromatic monohydroxy skeleton substituted with one or more alkyl groups having 5 or more carbon atoms is preferable. Specifically, octadecyl-3- (3,5-di- -Tert-butyl-4-hydroxyphenyl) propionate, pentaerythrityl-tetrakis {3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate}, 1,6-hexanediol-bis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) Benzene and the like are preferred, and pentaerythrityl-tetrakis {3- (3,5-di-t-butyl-4-hydroxyphenyl) pro Onato is more preferable.

Here, the content of the hindered phenol-based heat stabilizer (d) is preferably 0.0001 parts by weight or more and 1 part by weight or less, more preferably 0.001 parts by weight with respect to 100 parts by weight of the polycarbonate resin (a). Part to 0.3 part by weight, more preferably 0.005 part to 0.1 part by weight.
When the content is excessively small, the coloring suppression effect may be insufficient. Moreover, when there is too much said content, in the case of a metal mold | die surface or film shaping | molding, there exists a possibility that a deposit may increase on the surface of a cooling roll, and the surface external appearance of a product may be impaired. When the phosphite heat stabilizer and the hindered phenol heat stabilizer are used in combination, the effect is great.

  Release agents include higher fatty acids, higher fatty acid esters of mono- or polyhydric alcohols, natural animal waxes such as beeswax, natural plant waxes such as carnauba wax, natural petroleum waxes such as paraffin wax, and montan wax. Natural coal wax, olefin wax, silicone oil, organopolysiloxane and the like can be mentioned, and higher fatty acid and higher fatty acid ester of monohydric or polyhydric alcohol are particularly preferable.

  The higher fatty acid ester is preferably a partial ester or a total ester of a substituted or unsubstituted monovalent or polyhydric alcohol having 1 to 20 carbon atoms and a substituted or unsubstituted saturated fatty acid having 10 to 30 carbon atoms. . Such partial esters or total esters of monohydric or polyhydric alcohols and saturated fatty acids include stearic acid monoglyceride, stearic acid diglyceride, stearic acid triglyceride, stearic acid monosorbite, stearyl stearate, behenic acid monoglyceride, behenyl behenate, Pentaerythritol monostearate, pentaerythritol tetrastearate, pentaerythritol tetrapelargonate, propylene glycol monostearate, stearyl stearate, palmityl palmitate, butyl stearate, methyl laurate, isopropyl palmitate, biphenyl biphenate Sorbitan monostearate, 2-ethylhexyl stearate and the like. Of these, stearic acid monoglyceride, stearic acid triglyceride, pentaerythritol tetrastearate, and behenyl behenate are preferably used.

  As the higher fatty acid, a substituted or unsubstituted saturated fatty acid having 10 to 30 carbon atoms is preferable. Examples of such saturated fatty acids include myristic acid, lauric acid, palmitic acid, stearic acid, behenic acid and the like. One of these release agents (e) may be used alone, or two or more thereof may be mixed and used. The content of the release agent (e) is 0.0001 to 2 parts by weight, preferably 0.01 to 1 part by weight, more preferably 100 parts by weight of the polycarbonate resin (a). Is 0.1 to 0.5 parts by weight. If the content of the release agent is small, the effect tends to be small, and if it is excessively large, in the case of mold surface or film molding, the deposit on the cooling roll surface increases and the surface appearance of the product is impaired. There is a fear.

  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 amount of water introduced is usually 0.01 parts by weight to 0.5 parts by weight, preferably 0.1 parts by weight to 0.3 parts by weight, when the polycarbonate resin to be treated is 100 parts by weight. The number of vent ports may be one or plural, but preferably two or more.

<screw>
The extruder according to the present invention is characterized in that the screw includes a rotor. An example of this rotor is shown in FIG. Details will be described below.

  In order to suppress the 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. To do. 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 may be an element (screw element) composed of a plurality of pieces in order to have various functions. In general, a full flight consisting only of a spiral screw (flight) mainly for the purpose of transporting the resin (see FIG. 2 (b) as an example of a two-row full flight), a kneading disc for the purpose of resin kneading (Refer to FIG. 2 (c)), a reverse flight is used which is composed of a seal ring or the like for the purpose of resin sealing, and in which screws are arranged in the direction opposite to the resin transport direction depending on the purpose. There are two types (see FIG. 2 (d)) and three types depending on how the threads are cut. In the present invention, the amount of processing can be increased with respect to the screw diameter of the extruder, and shear heat generated by screw rotation. A double-striped deep groove type capable of suppressing the above is preferable.

Moreover, the element which consists of several pieces which comprise the screw of the extruder of this invention may be sufficient. In that case, at least one has a rotor. The total length of the rotor is preferably 10 to 30% of the total length of the screw. From the viewpoint of reducing residual phenol, 12% or more is more preferable. Further, from the viewpoint of the dispersibility of the additive, 25% or less is more preferable, and 20% or less is particularly preferable. If this range is significantly deviated, problems such as an increase in residual phenol and insufficient dispersion of additives may occur.
Moreover, it is preferable that the screw of an extruder can be decomposed | disassembled into several pieces of 0.10-10, preferably 0.20-3 in L / D. If it is less than 0.1, the film becomes too thin and may be deformed. If it is more than 10, it is difficult to change the screw configuration or clean the screw.

  Further, at least one piece of the element is preferably a kneading disk, and it is particularly preferable that the number of pieces of the kneading disk used for the screw is 10 or less. When the number of pieces of the kneading disc is more than 10, the resin temperature rises, and there is a risk that the strands will run out of gas due to the decomposition gas. The number of pieces of the kneading disc is more preferably 8 or less.

  Moreover, it is preferable that the total length of this kneading disk is 3 to 15% of the length of the whole screw, More preferably, it is 4 to 10%. 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 during devolatilization and kneading of the additive may be deteriorated.

  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.

  Further, the polycarbonate resin supplied to the extruder preferably has a glass transition temperature of 80 ° C. or higher, preferably 85 ° C. or higher, particularly preferably 90 ° C. or higher. When the glass transition temperature is too low, the heat resistance is inferior, and the field of use is limited when forming the obtained pellets into a molded product.

  On the other hand, if the glass transition temperature is high, the melt viscosity becomes too high, and in an industrial reactor having a practically upper limit of temperature, a polycarbonate resin having practical mechanical properties cannot be obtained, or thermal stability In the case of a polycarbonate resin that is inferior to the above, if the polymerization temperature is increased, the decomposition reaction may emerge and a polycarbonate resin having practical mechanical properties may not be obtained.

  Moreover, even if a polycarbonate resin is obtained by a polymerization reaction, a polycarbonate resin having a high glass transition temperature has a high melt viscosity in a region having a practical molecular weight. The glass transition temperature of the polycarbonate resin in the present invention is preferably less than 160 ° C., preferably 150 ° C. or less, particularly preferably 145 ° C. or less.

  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.

In the first aspect of the present invention, the temperature of the polycarbonate resin discharged from the extruder is preferably 290 ° C. or less, more preferably 280 ° C. or less, further preferably 270 ° C. or less, particularly preferably 265 ° C. It is as follows. When the polycarbonate resin discharged from the extruder exceeds 290 ° C., the polycarbonate resin tends 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. 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 shear heat generation tends to be suppressed by that amount. However, if the temperature of the polycarbonate resin itself is high, the deterioration tends to occur, resulting in a deterioration in hue and a decrease in molecular weight. 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.
In the second aspect of the present invention, the temperature of the polycarbonate resin discharged from the extruder is 265 ° C. or lower.

  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 these may vary depending on the screw rotation speed and the configuration of the screw element, 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, after the polycarbonate resin obtained by polycondensation is devolatilized and mixed with additives in the extruder, the filter is used to remove foreign matters such as burns and gels contained in the resin. It is preferable to filter. 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) and a filtering member (hereinafter also referred to as media), and storing these filters (in some cases, a plurality or plural). It is used in the form of a unit (sometimes called a filter unit) stored in a container.

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

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 opening defined as 99% filtration accuracy means the value of χ when the βχ value represented by the following formula (5) 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) (5)
(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 in 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. 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 filtering with the filter becomes too low, the polycarbonate has a high melt viscosity, and the load on the filter increases and may cause damage to the filter. Above, more preferably 230 ° C or higher, particularly preferably 240 ° C or higher.

  In the method of the present invention, the temperature of the polycarbonate resin discharged from the die after devolatilization and mixing in the extruder, preferably through filtration with the filter, is preferably 200 ° C. or more, preferably 220. The upper limit 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 is too low, the melt viscosity becomes high and the extruded strand is not stable and may be difficult to be pelletized with a rotary cutter or the like. . 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.

  Normally, when polycarbonate resin is mixed with the extruder, shear heat is generated due to screw rotation, and when using a filter, if the filter is filtered with a small mesh, the temperature rises due to shear heat and is discharged from the die. To control the temperature of the polycarbonate resin, the throughput of the polycarbonate resin in the extruder, barrel temperature setting, screw rotation speed and peripheral speed, element configuration, etc., opening of the filter, filtration area, temperature It is important to comprehensively control the setting, the temperature setting of the pipe through which the die and polymer flow, the molecular weight of the polycarbonate resin, and the like.

In the method of the present invention, the terminal double bond of the polycarbonate resin before introduction into the extruder obtained by polycondensation by the transesterification reaction is kneaded with the extruder at Xμeq / g, and in some cases, the filter When the terminal double bond of the polycarbonate resin constituting the polycarbonate resin pellet obtained by using a cutter after cooling is Yμeq / g, it is discharged as follows. It is preferable to satisfy Expression (6).
Y−X ≦ 10 (6)
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.

Further, in the method of the present invention, the reduced viscosity (ηsp / c) of the polycarbonate resin supplied to the extruder obtained by polycondensation by the transesterification reaction is kneaded with a, the extruder. Is filtered using the filter, discharged in the form of a strand from a die, cooled, and when the reduced viscosity (ηsp / c) of the polycarbonate resin constituting the polycarbonate resin pellet obtained using the cutter is B In addition, it is preferable to satisfy the following formula (7).
0.8 <B / a <1.1 (7)
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 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 rises in the extruder, 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.

Further, when a filter is installed on the downstream side of the extruder in the method of the present invention, the reduced viscosity (ηsp / c) of the polycarbonate resin supplied to the filter is filtered using A, the filter, and the strand from the die. When the reduced viscosity (ηsp / c) of the polycarbonate resin constituting the polycarbonate resin pellet obtained by using a cutter is discharged after cooling in the form of B, the following formula (8) is preferably satisfied.
0.8 <B / A <1.1 (8)
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, which is not preferable. 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.

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

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

  Further, the polycarbonate resin devolatilized and mixed by the extruder and optionally filtered by the filter is cooled and solidified, and pelletized by a rotary cutter or the like. It is preferred to use a cooling method. 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.

(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, resin, ceramic, etc. can be used. From the viewpoint of heat resistance and color reduction, the metal content is 80% or less. A filter is preferable, and stainless steel such as SUS304, SUS316, SUS316L, and SUS310S is particularly 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, it is necessary to appropriately select monomer preparation conditions, polymerization reaction conditions, filtration conditions, extrusion conditions, screw elements, thermal stabilizers, mold release agents and the like as described above.

  The molecular weight of the polycarbonate resin constituting the polycarbonate resin pellet obtained in the method of the present invention can be represented by a reduced viscosity (ηsp / c), and the reduced viscosity is usually 0.3 dL / g or more, preferably 0. .35 dL / g or more, more preferably 0.4 dL / g 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. is there. 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 reduced viscosity is precisely measured by using a Ubbelohde viscosity tube at a temperature of 20.0 ° C. ± 0.1 ° C. by accurately measuring polycarbonate resin pellets, using methylene chloride as a solvent, and preparing precisely at 0.6 g / dL. To do.

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 more, preferably 800 Pa · s or more, particularly preferably 1000 Pa · s. The upper limit is usually 3000 Pa · s or less, preferably 2000 Pa · s or less, and particularly preferably 1500 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.

  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 as a raw material to the carbonic acid diester, 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 (4), phenol 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. Additives such as heat stabilizers, neutralizers, UV absorbers, mold release agents, colorants, antistatic agents, lubricants, lubricants, plasticizers, compatibilizers, flame retardants to the polycarbonate resin as necessary Can be kneaded with the extruder. Moreover, it can also mix using a tumbler, a super mixer, a floater, a V-type blender, a Nauta mixer, a Banbury mixer, another extruder, etc.

According to the method of the present invention, polycarbonate resin pellets with less coloring and less foreign matter can be stably obtained. Therefore, preferably 1000 foreign matters having a thickness of 25 μm or more contained in a film having a thickness of 30 μm ± 5 μm formed from the resin. / M ² or less, more preferably 500 pieces / m ² or less, and most preferably 200 pieces / m ² or less. Thus, the characteristic that there are few foreign substances is especially suitable when using a polycarbonate resin pellet for an optical use.

  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 phenol (PHL) content About 1.25 g of polycarbonate resin pellets are precisely weighed and dissolved in 7 ml of methylene chloride to form a solution, and then acetone is added so that the total amount becomes 25 ml. went. Next, the treatment liquid was filtered through a 0.2 μm disk filter and quantified by liquid chromatography.

(2) Hue of polycarbonate resin pellets The obtained pellets are packed into 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.

The abbreviations of the compounds used in the description of the following examples are as follows.
・ ISB: Isosorbide (Rocket Fleure, trade name POLYSORB)
CHDM: 1,4-cyclohexanedimethanol (manufactured by Shin Nippon Rika Co., Ltd., trade name SKY CHDM)
・ 1,6-HD: 1,6-hexanediol (manufactured by BASF)
・ DPC: Diphenyl carbonate (Mitsubishi Chemical Corporation)

<Example 1>
In a raw material preparation tank sufficiently substituted with nitrogen (oxygen concentration 0.0005 vol% to 0.001 vol%), the molar ratio of BHEPF / ISB / PEG (average molecular weight 1000) / DPC was 43.2 / 55.6 / 1.2. / 99 A first polymerization reactor comprising a heat medium jacket using oil as a heat medium, a heat medium internal coil, a stirring blade, a distillation pipe connected to a vacuum pump, and a condenser. In addition, at the same time as supplying a constant amount, magnesium acetate tetrahydrate made into an aqueous solution from the catalyst supply pipe connected to the raw material supply pipe is 19 × 10 ⁻⁶ mol per 1 mol of all dihydroxy compounds (converted to magnesium metal atom) Was continuously fed so as to be. 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 was controlled to be constant at 196 ° C., pressure 26.3 kPa, residence time 1.5 hours, and the reaction solution was continuously fed from the bottom of the reaction vessel. And was fed 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 internal temperature was 207 ° C., the pressure was 23.9 kPa, and the residence time was controlled to be constant at 1 hour. 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 to be constant at an internal temperature of 218 ° C., a pressure of 20.9 kPa, and a residence time of 1 hour, and the polycondensation reaction proceeds while distilling off the by-produced phenol to react the reaction solution. Continuously withdrawn from the bottom of the tank 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 did. The fourth polymerization reactor was controlled so that the internal temperature near the inlet was 220 ° C., the internal temperature near the outlet was 240 ° C., the pressure was 1.4 kPa, and the residence time was 2 hours, and the polycondensation reaction was further advanced. .
The obtained polycarbonate resin was continuously supplied to a twin screw extruder having an additive supply port and three vent ports, L / D = 42, and the screw configuration of the screw 1 shown in Table 1. The temperature at the time of supply was 248 ° C. In the extruder, 2000 ppm of water was supplied to the polycarbonate resin to be treated, a side feeder was installed downstream of the water supply nozzle and the subsequent vent port, and pentaerythrityl tetrakis [3- (3,5- Di-t-butyl-4-hydroxyphenyl) propionate] (trade name: IRGANOX1010) with respect to 100 parts by weight of polycarbonate resin, 0.1 part by weight of tris (2,4-di-t-butylphenyl) phosphite ( The product name: ADK STAB 2112) was continuously supplied to the same amount of 0.05 parts by weight. The vent port was connected to a vacuum pump to remove volatile components contained in the polycarbonate resin. Table 2 shows various setting conditions and results of the extruder (the temperature of the polycarbonate resin discharged from the extruder, the remaining PHL and YI of the obtained pellets).

<Examples 2-3 and Comparative Examples 1-2>
The same procedure as in Example 1 was performed except that the screw configuration, the screw rotation speed of the extruder, and the amount of water injection were changed as shown in Table 2. The results are shown in Table 2.

<Example 4>
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 was continuously supplied to a twin screw extruder having an additive supply port and three vent ports, L / D = 42, and a screw configuration of screw 1 of Table 1 (kneading disk). The other screw element consists of full flight and seal ring). In the extruder, 2000 ppm 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. A side feeder is installed downstream of the water supply nozzle and the subsequent vent port, and pentaerythrityl tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] (trade name: IRGANOX 1010) 0.1 parts by weight of 100 parts by weight of polycarbonate resin, 0.05 parts by weight of tris (2,4-di-t-butylphenyl) phosphite (trade name: ADK STAB 2112), stearic acid monoglyceride (RIKEN) (Manufactured by Vitamin Co., Ltd.) was also continuously supplied to 0.3 parts by weight. Table 2 shows various setting conditions and results of the extruder (the temperature of the polycarbonate resin discharged from the extruder, the remaining PHL and YI of the obtained pellets).

<Comparative Examples 3-4>
The same procedure as in Example 4 was performed except that the screw configuration and the screw rotation speed of the extruder were changed as shown in Table 2. The results are shown in Table 2.

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 reactor 6b Second vertical stirring reactor 6c Third vertical stirring reactor 6d Fourth horizontal stirring reactor 7a, 7b, 7c Max blend blade 7d Two-shaft 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 (11)

A catalyst and a dihydroxy compound and a carbonic acid diester as raw material monomers are subjected to polycondensation by transesterification, and the resulting polycarbonate resin is supplied to an extruder to produce polycarbonate resin pellets,
The screw of the extruder comprises a rotor,
The dihydroxy compound includes at least a specific dihydroxy compound having a site represented by the following general formula (1) in a part of the structure;
The screw of the extruder is composed of a plurality of pieces of elements, and at least one piece of the elements is a kneading disc;
A method for producing polycarbonate resin pellets, characterized in that the total length of the kneading disks used for the screw of the extruder is 3 to 15% of the total length of the screw.
(However, the site represented by the above general formula (1) unless it is part of _-CH 2 -O-H.) A catalyst and a dihydroxy compound and a carbonic acid diester as raw material monomers are subjected to polycondensation by transesterification, and the resulting polycarbonate resin is supplied to an extruder to produce polycarbonate resin pellets,
The screw of the extruder comprises a rotor,
The dihydroxy compound includes at least a specific dihydroxy compound having a site represented by the following general formula (1) in a part of the structure;
The method for producing polycarbonate resin pellets, characterized in that the temperature of the polycarbonate resin discharged from the extruder is 265 ° C or lower.
(However, the site represented by the above general formula (1) unless it is part of _-CH 2 -O-H.)   The manufacturing method of the polycarbonate resin pellet of Claim 1 or 2 which supplies the said polycarbonate resin obtained by polycondensation by transesterification to the said extruder in a molten state.   The screw of the extruder is composed of a plurality of elements, at least one of the elements is a rotor, and the total length of the rotor is 10 to 30% of the total length of the screw, The manufacturing method of the polycarbonate resin pellet of any one of Claims 1-3 to do.   The screw of the extruder is composed of a plurality of pieces of elements, and at least one piece of the elements is a kneading disc, and the number of pieces of the kneading disc is 10 or less. The manufacturing method of the polycarbonate resin pellet of any one of claim | item 1-3.   The glass transition temperature of the said polycarbonate resin is 90 degreeC or more and less than 160 degreeC, The manufacturing method of the polycarbonate resin pellet of any one of Claims 1-5.   The method for producing a polycarbonate resin pellet according to any one of claims 1 to 6, wherein a content of the monohydroxy compound contained in the polycarbonate resin pellet is less than 0.1 wt%.   The manufacturing method of the polycarbonate resin pellet of any one of Claims 1-7 which filters the said raw material monomer with a raw material filtration filter before polycondensation.   The manufacturing method of the polycarbonate resin pellet of any one of Claims 1-8 which performs operation which knead | mixes a heat stabilizer using the said extruder.   The method for producing a polycarbonate resin pellet according to any one of claims 1 to 9, 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 polycarbonate resin according to claim 1, wherein the specific dihydroxy compound is at least one dihydroxy compound selected from a dihydroxy compound represented by the following general formula (2) and the following general formula (10). Pellet manufacturing method.
(In the above formula (10), R ^{1 to} R ⁴ are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted 6 to 20 carbon atoms. Represents a cycloalkyl group or a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, and the same or different groups are arranged as each of the four substituents on each benzene ring. ¹ and X ² are each independently a substituted or unsubstituted alkylene group having 2 to 10 carbon atoms, a substituted or unsubstituted cycloalkylene group having 6 to 20 carbon atoms, or a substituted or unsubstituted group. Represents an arylene group having 6 to 20 carbon atoms, m and n are each independently an integer of 0 to 5)