WO2012133237A1

WO2012133237A1 - Method for manufacturing polycarbonate resin, polycarbonate resin, polycarbonate-resin film, and methods for manufacturing polycarbonate-resin pellets and polycarbonate-resin films

Info

Publication number: WO2012133237A1
Application number: PCT/JP2012/057622
Authority: WO
Inventors: 正志横木; 慎悟並木; 剛一永尾; 正規山本
Original assignee: 三菱化学株式会社
Priority date: 2011-03-31
Filing date: 2012-03-23
Publication date: 2012-10-04
Also published as: CN103459112A; JP2012214729A; KR20130122980A; KR20130116376A; JP2013010965A; KR101380522B1; JP5229418B2

Abstract

The present invention relates to a polycarbonate-resin manufacturing method whereby polycarbonate-resin pellets or polycarbonate-resin films that contain little foreign material and exhibit excellent optical properties, thermal stability, hue, and mechanical strength are manufactured efficiently and stably.

Description

Production method of polycarbonate resin, polycarbonate resin, polycarbonate resin film, and production method of polycarbonate resin pellet and polycarbonate resin film

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 / electronic parts, automotive parts, optical recording media, lenses, and other optical fields. Widely used as engineering plastics.

However, for retardation film applications or lens applications such as flat panel displays, which have been rapidly spreading recently, more advanced optical properties such as low birefringence or low photoelastic coefficient have been required, and conventional bisphenols have been required. Aromatic polycarbonate resins containing monomers as monomer components cannot meet the demand.

In recent years, a polycarbonate resin using a dihydroxy compound having a fluorene structure as a monomer has been proposed, and a retardation film that exhibits a specific retardation (for example, Patent Documents 1 to 4) or a lens having a small birefringence (for example, Patent Documents). Application to 5, 6) has been proposed.

In applications where such high optical properties are required, higher optical reliability is required compared to general injection molded parts or extruded parts, and contamination or coloring of foreign matters has been a particularly serious problem. As a method for solving this, a method is disclosed in which a polycarbonate resin having a fluorene structure is extruded with an extruder and then filtered with a filter (for example, Patent Document 7).

Japanese Patent No. 3325560 Japanese Unexamined Patent Publication No. 2003-90914 Japanese Unexamined Patent Publication No. 2007-171756 Japanese Laid-Open Patent Publication No. 2010-230832 Japanese Laid-Open Patent Publication No. 2004-67990 Japanese Unexamined Patent Publication No. 2010-189508 Japanese Unexamined Patent Publication No. 2007-70392

However, the polycarbonate resin having a fluorene structure has a problem that when it is filtered using a filter in a melted state, the melt viscosity is too high and the resin is deteriorated due to shear heat generation during filtration.

Also, if you want to use a filter with high filtration accuracy while suppressing deterioration due to shear heat generation with the filter, you will have to reduce the amount of polycarbonate resin treatment or increase the filtration area, and consequently require filtration treatment The time becomes longer, causing problems such as the deterioration of the polycarbonate resin.

On the other hand, in order to shorten the time required for the filtration treatment, if the melt viscosity of the polycarbonate resin is to be lowered, it is necessary to lower the molecular weight of the polycarbonate resin itself or raise the filtration temperature.

However, if the molecular weight of the polycarbonate resin itself is lowered, the mechanical strength or heat resistance is lowered. If the temperature during filtration is increased, the resin is decomposed and deteriorated, and a resin satisfying physical properties such as mechanical strength cannot be obtained. In addition, there was a dilemma in that pelletization or film formation could not be performed stably by facilitating coloring, or by causing outgassing of strands or silver strip defects of the film by the decomposition gas.

The object of the present invention is to eliminate the above-mentioned conventional problems, and to efficiently and stably produce polycarbonate resin pellets or polycarbonate resin films having excellent optical characteristics, thermal stability, hue, mechanical strength, and few foreign matters. It is to provide a method of manufacturing.

As a result of intensive studies to solve the above problems, the present inventor has obtained optical characteristics by filtering the polycarbonate resin under specific conditions in a method of producing a polycarbonate resin pellet or film having a fluorene structure. The present inventors have found a method for stably producing polycarbonate resin pellets or polycarbonate resin films that are excellent in mechanical strength and hue and have few foreign matters.

That is, the gist of the present invention resides in the following [1] to [28].
[1] A method for producing a polycarbonate resin in which a polycarbonate resin obtained by polycondensation of a dihydroxy compound and a carbonic acid diester is filtered and then solidified by cooling, wherein the dihydroxy compound is represented by the following general formula (1) The polycarbonate resin is filtered so that the filter has an opening of 50 μm or less and the temperature of the polycarbonate resin after filtration using the filter is 200 ° C. or higher and lower than 280 ° C. A method for producing a polycarbonate resin.

[In the general formula (1), R ₁ to R ₄ are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted carbon number 6 to 20 carbon atoms. Or a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, and X is a substituted or unsubstituted alkylene group having 2 to 10 carbon atoms, substituted or unsubstituted carbon number It represents a cycloalkylene group having 6 to 20 carbon atoms or a substituted or unsubstituted arylene group having 6 to 20 carbon atoms, and m and n are each independently an integer of 0 to 5. ]

[2] The method for producing a polycarbonate resin according to [1], wherein the polycarbonate resin obtained by cooling and solidifying has a glass transition temperature of 50 ° C. or higher and lower than 180 ° C.

[3] The polycarbonate resin according to [1] or [2], wherein the reduced viscosity (ηsp / c) of the polycarbonate resin obtained by cooling and solidifying is 0.2 dL / g or more and 0.6 dL / g or less. Manufacturing method.

[4] The polycarbonate resin obtained by cooling and solidifying has a melt viscosity of 1000 Pa · s to 5000 Pa · s at a shear rate of 91.2 sec ⁻¹ measured at 240 ° C. [1] to [3]. A method for producing a polycarbonate resin according to any one of the above.

[5] The polycarbonate resin obtained by cooling and solidifying is obtained by using 18 mol% or more of the dihydroxy compound represented by the general formula (1) as a raw material monomer with respect to the total dihydroxy compound [ [1] The method for producing a polycarbonate resin according to any one of [4].

[6] When the reduced viscosity (ηsp / c) of the polycarbonate resin before filtering with the filter is A, and the reduced viscosity (ηsp / c) of the polycarbonate resin obtained by cooling and solidification is B, The method for producing a polycarbonate resin according to any one of [1] to [5], which satisfies the following formula (2).
0.8 <B / A <1.1 (2)

[7] The polycarbonate resin is obtained by polycondensation of at least a dihydroxy compound represented by the general formula (1) and a carbonic acid diester by a transesterification reaction in the presence of a catalyst. [1] Thru | or the manufacturing method of polycarbonate resin in any one of [6].

[8] The method for producing a polycarbonate resin according to [7], wherein the polycarbonate resin obtained by the polycondensation is supplied to the filter in a molten state without being solidified and filtered.

[9] The polycondensation is performed using a catalyst, and the catalyst is at least one metal compound selected from the group consisting of a metal of Group 2 of the long-period periodic table and lithium [7]. Or the manufacturing method of polycarbonate resin as described in [8].

[10] In addition to the dihydroxy compound represented by the general formula (1) as a raw material monomer, the polycarbonate resin uses a dihydroxy compound having a portion represented by the following general formula (3) in a part of the structure [ [1] The method for producing a polycarbonate resin according to any one of [9].

[However, the case where the moiety represented by the general formula (3) is a part of —CH ₂ —O—H is excluded. ]

[11] The dihydroxy compound having the moiety represented by the general formula (3) is a compound having a cyclic ether structure, and the moiety represented by the general formula (3) is a part of the cyclic ether structure [ [10] A process for producing a polycarbonate resin according to [10].

[12] In addition to the dihydroxy compound represented by the general formula (1) as a raw material monomer, the polycarbonate resin is represented by the following dihydroxy compound represented by the following general formula (4) and the following general formula (5). [1] to [11], wherein one or more dihydroxy compounds selected from the group consisting of a dihydroxy compound and a dihydroxy compound represented by the following formula (6) are used. A method for producing a polycarbonate resin.

[In the general formula (4), R ₅ represents a substituted or unsubstituted cycloalkylene group having 4 to 20 carbon atoms. ]

[In the general formula (5), R ₆ represents a substituted or unsubstituted cycloalkylene group having 4 to 20 carbon atoms. ]

[In General Formula (6), R ₁₁ represents a chain alkylene group having 2 to 20 carbon atoms. ]

[13] The filter is stored in a container, and a value obtained by dividing the internal volume (m ³ ) of the storage container by the flow rate (m ³ / min) of the polycarbonate resin to be filtered is 2 to 10 minutes. [1] A method for producing a polycarbonate resin according to any one of [12].

[14] The method for producing a polycarbonate resin according to any one of [1] to [13], wherein the linear velocity of the molten resin on the filter surface is 0.01 to 0.5 m / h.

[15] Any one of [1] to [14], wherein the content of the aromatic monohydroxy compound contained in the polycarbonate resin obtained by cooling and solidifying is 0.0001% by weight or more and less than 0.2% by weight. A method for producing a polycarbonate resin as described in 1. above.

[16] The method for producing a polycarbonate resin according to any one of [1] to [15], wherein the raw material monomer is filtered with a raw material filter before the polycondensation reaction.

[17] The method for producing a polycarbonate resin according to any one of [1] to [16], wherein the filter is made of a metal that has been previously roasted at a temperature of 350 ° C. or higher and 500 ° C. or lower.

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

[19] The polycarbonate resin according to any one of [1] to [18], wherein the polycarbonate resin is devolatilized by a twin-screw extruder having a vent port, and then supplied to the filter and filtered. Manufacturing method.

[20] The screw of the extruder is composed of a plurality of elements, and at least one of the elements is a kneading disk, and the total length of the kneading disk is 20% of the total length of the screw. The method for producing a polycarbonate resin according to [19], which is as follows.

[21] When the weight of the resin extruded per hour by the extruder is W (kg / h) and the cross sectional area of the barrel of the extruder is S (m ² ), the following formula (7) is satisfied: [19] The method for producing a polycarbonate resin according to [20].

12000 ≦ W / S ≦ 60000 (7)
[22] The method for producing a polycarbonate resin according to any one of [19] to [21], wherein the temperature of the polycarbonate resin supplied to the extruder is 200 ° C. or higher and lower than 250 ° C.

[23] The method for producing a polycarbonate resin according to any one of [19] to [22], wherein the temperature of the polycarbonate resin supplied to the filter is 230 ° C. or higher and lower than 280 ° C.

[24] When the reduced viscosity (ηsp / c) of the polycarbonate resin supplied to the extruder is a and the reduced viscosity (ηsp / c) of the polycarbonate resin obtained by cooling and solidification is B, the following formula The method for producing a polycarbonate resin according to any one of [19] to [23], which satisfies (8).
0.8 <B / a <1.1 (8)

[25] The method for producing a polycarbonate resin according to any one of [19] to [24], wherein a gear pump is disposed between the extruder and the filter.

[26] A polycarbonate resin having a yellow index value of 70 or less obtained by the production method according to any one of [1] to [25].

[27] A polycarbonate resin obtained by the production method according to any one of [1] to [25] or a film having a thickness of 20 μm to 200 μm obtained by extrusion molding of the polycarbonate resin according to [26]. A polycarbonate resin film having a maximum length of 25 μm or more contained in the film of 1000 / m ² or less.

[28] A polycarbonate resin obtained by using a dihydroxy compound having a structural unit represented by the following general formula (1) as a raw material monomer is filtered using a filter in a molten state, discharged from a die, and cooled. Thereafter, a method for producing a polycarbonate resin pellet or a polycarbonate resin film, wherein the dihydroxy compound includes at least a dihydroxy compound having a site represented by the following general formula (1) in a part of the structure, and the aperture of the filter Is 50 μm or less, and the temperature of the resin discharged from the die is 200 ° C. or higher and lower than 280 ° C. A method for producing a polycarbonate resin pellet or polycarbonate resin film,

INDUSTRIAL APPLICABILITY According to the present invention, a retardation film having excellent optical characteristics, mechanical strength and hue and having less foreign matters, and further applicable to optical fields such as camera lenses, viewfinder lenses, CCD or CMOS lenses, etc. Polycarbonate resin pellets or films having excellent performance can be produced efficiently and stably.

FIG. 1 is a process diagram showing an example of a manufacturing process according to the present invention.

DESCRIPTION OF EMBODIMENTS Embodiments of the present invention will be described in detail below. However, the description of the constituent elements described below is an example (representative example) of an embodiment of the present invention. It is not limited to the contents. In addition, when the expression “˜” is used in this specification, it is used in the meaning including numerical values or physical values before and after the expression.

<Raw material monomers and polymerization catalyst>
(Dihydroxy compound)
In the method for producing a polycarbonate resin of the present invention, a dihydroxy compound is used as a raw material monomer, and at least one of the dihydroxy compounds is a specific dihydroxy compound having a site represented by the following general formula (1) in a part of the structure. (Hereinafter sometimes referred to as “the dihydroxy compound of the present invention”).

In the general formula (1), R ₁ to R ₄ are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted carbon atom having 6 to 20 carbon atoms. Represents a cycloalkyl group or a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, and X is a substituted or unsubstituted alkylene group having 2 to 10 carbon atoms, substituted or unsubstituted 6 carbon atoms. Represents a cycloalkylene group having 20 carbon atoms, or a substituted or unsubstituted arylene group having 6 to 20 carbon atoms, and m and n are each independently an integer of 0 to 5.

The dihydroxy compound of the present invention is a compound represented by the above general formula (1). In the formula, each of R ₁ to R ₄ independently represents a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 6 to 20 carbon atoms, or Represents a substituted or unsubstituted aryl group having 6 to 20 carbon atoms.

Here, examples of the substituent include an ester group, an ether group, a carboxylic acid, an amide group, and a halogen. Of these, a hydrogen atom, an unsubstituted alkyl group having 1 to 4 carbon atoms, an unsubstituted cycloalkyl group having 5 to 7 carbon atoms, or a phenyl group is preferable.

X is an unsubstituted or ester group, an ether group, a carboxylic acid, an amide group, a halogen-substituted alkylene group having 2 to 10 carbon atoms, an unsubstituted or ester group, an ether group, a carboxylic acid, an amide group, a halogen A cycloalkylene group having 6 to 20 carbon atoms substituted with an aryl group or the like, or an arylene group having 6 to 20 carbon atoms which is unsubstituted or substituted with an ester group, an ether group, a carboxylic acid, an amide group, a halogen or the like. And is preferably an alkylene group having 2 to 6 carbon atoms.

M and n are each independently an integer of 0 to 5, preferably 0 or 1, particularly preferably a compound of m = 0 and n = 0, or a compound of m = 1 and n = 1.

Specific examples of the dihydroxy compound of the present invention include 9,9-bis (4-hydroxyphenyl) fluorene, 9,9-bis (4-hydroxy-3-methylphenyl) fluorene, and 9,9-bis. (4-hydroxy-3-ethylphenyl) fluorene, 9,9-bis (4-hydroxy-3-n-propylphenyl) fluorene, 9,9-bis (4-hydroxy-3-isopropylphenyl) fluorene, 9, 9-bis (4-hydroxy-3-n-butylphenyl) fluorene, 9,9-bis (4-hydroxy-3-sec-butylphenyl) fluorene, 9,9-bis (4-hydroxy-3-tert- Butylphenyl) fluorene, 9,9-bis (4-hydroxy-3-cyclohexylphenyl) fluorene, 9,9-bis (4- Loxy-3-phenylphenyl) fluorene, 9,9-bis [4- (2-hydroxyethoxy) phenyl] fluorene, 9,9-bis [4- (2-hydroxyethoxy) -3-methylphenyl] fluorene, 9 , 9-bis [4- (2-hydroxyethoxy) -3-isopropylphenyl] fluorene, 9,9-bis [4- (2-hydroxyethoxy) -3-isobutylphenyl] fluorene, 9,9-bis [4 -(2-hydroxyethoxy) -3-tert-butylphenyl] fluorene, 9,9-bis [4- (2-hydroxyethoxy) -3-cyclohexylphenyl] fluorene, 9,9-bis [4- (2- Hydroxyethoxy) -3-phenylphenyl] fluorene, 9,9-bis [4- (2-hydroxyethoxy) -3,5-dimethyl Ruphenyl] fluorene, 9,9-bis [4- (2-hydroxyethoxy) -3-tert-butyl-6-methylphenyl] fluorene, 9,9-bis [4- (3-hydroxy-2,2-dimethyl) Propoxy) phenyl] fluorene and the like.

Among these, 9,9-bis (4-hydroxy-3-methylphenyl) fluorene, 9,9-bis [4- (2-hydroxyethoxy) phenyl] fluorene or 9,9-bis (4- (2-hydroxyethoxy) -3-methylphenyl) fluorene, particularly preferably 9,9-bis (4- (2-hydroxyethoxy) phenyl) fluorene.

Among these, 9,9-bis (4-hydroxy-3-methylphenyl) fluorene or 9,9-bis [4- (2-hydroxyethoxy) phenyl] fluorene is preferred from the viewpoint of handling properties and physical properties of the obtained polymer. Is preferably 9,9-bis [4- (2-hydroxyethoxy) phenyl] fluorene.

The polycarbonate resin of the present invention is preferably obtained by using 18 mol% or more of the specific dihydroxy compound having the structural unit represented by the general formula (1) as a raw material monomer with respect to the total dihydroxy compound, More preferably, it is 20 mol% or more, Especially preferably, it is 25 mol% or more, Most preferably, it is 30 mol% or more. Moreover, it is preferably 90 mol% or less, more preferably 70 mol% or less, and particularly preferably 50 mol% or less.

If the amount of the monomer having the structural unit is too small, the obtained polycarbonate resin may not exhibit the desired optical performance. If the amount is too large, the melt viscosity of the resulting polycarbonate resin will be high, making it difficult to filter using a filter with a small opening, resulting in increased foreign matter, and making pelletization or film formation difficult. There is. Also, if a filter with a small aperture is used forcibly, the filter may be damaged, or the polycarbonate resin may be colored or the molecular weight may be reduced.

Desired optical performance includes coloring, foreign matter, or phase difference that affects light transmittance. In particular, when the polycarbonate resin of the present invention is used as a quarter-wave plate for a retardation film, it is important to have a retardation in the vicinity of a quarter of the wavelength in any wavelength region. For this purpose, it is necessary to provide so-called birefringence reverse wavelength dispersion, in which the birefringence decreases as the wavelength decreases and increases as the wavelength increases.

The birefringence wavelength dispersibility is measured by preparing a stretched film having a uniform thickness, measuring a retardation (R450) at a measurement wavelength of 450 nm and a retardation (R550) at 550 nm, and a ratio of R450 to R550 (R450 / R550). ) Can be evaluated.

If the value is smaller than 1, it indicates reverse wavelength dispersion (sometimes referred to as negative wavelength dispersion). In the present invention, R450 / R550 is preferably 0.80 to 0.95, more preferably 0.85 to 0.93, and particularly preferably 0.87 to 0.91. Reverse wavelength dispersion cannot be achieved if the structural unit represented by the general formula (1) is too much or too little, but is also affected by the structure or content of other structural units. .

In the method for producing a polycarbonate resin of the present invention, a dihydroxy compound represented by the general formula (3) can be used as a raw material monomer.

However, the case where the site represented by the general formula (3) is a part of —CH ₂ —O—H is excluded.

Specific examples of the dihydroxy compound represented by the general formula (3) include oxyalkylene glycols such as diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, polypropylene glycol, and polytetramethylene glycol; Examples thereof include compounds having a cyclic ether structure such as an anhydrosugar alcohol represented by the dihydroxy compound represented by the general formula (9) and a spiro glycol represented by the following general formula (10).

Among these, diethylene glycol, triethylene glycol, or polyethylene glycol is preferable from the viewpoints of availability, handling, reactivity during polymerization, and hue of the obtained polycarbonate resin.

From the viewpoint of heat resistance, an anhydrous sugar alcohol represented by the dihydroxy compound represented by the following general formula (9), or a cyclic ether structure such as spiroglycol represented by the following general formula (10) [preferably, A compound having a moiety represented by the general formula (3) that is part of a cyclic ether structure] is preferred.

In addition, examples of the dihydroxy compound represented by the general formula (9) include isosorbide, isomannide, and isoide which are related to stereoisomers. Among these dihydroxy compounds, isosorbide obtained by dehydration condensation of sorbitol produced from various starches that are abundant as resources and are readily available is easy to obtain and manufacture, optical properties and moldability From the viewpoint of the above, it is most preferable.

In the present invention, the amount used when using a compound having a cyclic ether structure such as isosorbide or spiroglycol is not limited, but the lower limit thereof is preferably 10 mol% or more, more preferably 20 mol% or more, Especially preferably, it is 30 mol% or more, Most preferably, it is 40 mol% or more. Moreover, as an upper limit, Preferably it is 90 mol% or less, More preferably, it is 70 mol% or less, Most preferably, it is 60 mol% or less.

If the amount of the monomer having the structural unit is too small, the obtained polycarbonate resin may not exhibit the desired optical performance. If the amount is too large, not only the desired optical performance may not be exhibited, but also the thermal stability of the obtained polycarbonate resin is adversely affected, the melt viscosity becomes high, and pelletization or film formation is difficult. There is a possibility of becoming.

In the method for producing a polycarbonate resin of the present invention, a dihydroxy compound represented by the general formula (4) can be used as a raw material monomer.

In the general formula (4), R ₅ represents a substituted or unsubstituted cycloalkylene group having 4 to 20 carbon atoms.

Examples of the dihydroxy compound represented by the general formula (4) include a plurality of compounds such as 2,6-decalindiol, 1,5-decalindiol, 2,3-decalindiol tricyclodecanediol, and pentacyclopentadecanediol. Compounds having an alicyclic structure, 1,2-cyclopentanediol, 1,3-cyclopentanediol, 1,2-cyclohexanediol, 1,3-cyclohexanediol, 1,4-cyclohexanediol, 2-methyl-1 , 4-cyclohexanediol, 1,3-tetramethylcyclobutanediol, and other compounds containing a monocyclic cycloalkylene group. By setting it as a monocyclic structure, the toughness when the polycarbonate resin obtained is used as a film can be improved.

Moreover, the compound containing a 5-membered ring structure or a 6-membered ring structure is mentioned normally. By being a 5-membered ring structure or a 6-membered ring structure, the heat resistance of the obtained polycarbonate resin can be increased. The six-membered ring structure may be fixed in a chair shape or a boat shape by a covalent bond.

Further, when it has a substituent, the substituent is preferably an alkyl group having 1 to 4 carbon atoms.

Specific examples of the dihydroxy compound represented by the general formula (4) include 1,2-cyclopentanediol, 1,3-cyclopentanediol, 1,2-cyclohexanediol, and 1,3-cyclohexane. Examples thereof include diol, 1,4-cyclohexanediol and 2-methyl-1,4-cyclohexanediol.

In the method for producing a polycarbonate resin of the present invention, a dihydroxy compound represented by the general formula (5) can be used as a raw material monomer.

In the general formula (5), R ₆ represents a substituted or unsubstituted cycloalkylene group having 4 to 20 carbon atoms.

Examples of the dihydroxy compound represented by the general formula (5) include a plurality of compounds such as 2,3-norbornane dimethanol, 2,5-norbornane dimethanol, adamantane dimethanol, decalin dimethanol, and tricyclotetradecane dimethanol. Examples thereof include compounds having an alicyclic structure and compounds containing a monocyclic cycloalkylene group such as 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol and 1,4-cyclohexanedimethanol.

When a dihydroxy compound having a plurality of alicyclic structures is used, the heat resistance may be improved, but the toughness may be deteriorated, or the viscosity at the time of melting may be increased and the fluidity may be deteriorated. Therefore, from the viewpoint of improving the toughness and fluidity at the time of melting, a dihydroxy compound having a monocyclic structure, particularly a dihydroxy compound containing a 5-membered ring structure or a 6-membered ring structure is preferable.

The heat resistance of the obtained polycarbonate resin can be improved by being a 5-membered ring structure or a 6-membered ring structure. The six-membered ring structure may be fixed in a chair shape or a boat shape by a covalent bond.

Further, when it has a substituent, the substituent is preferably an alkyl group having 1 to 4 carbon atoms. Specific examples include 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol and 1,4-cyclohexanedimethanol.

Of the above-described specific examples of the alicyclic dihydroxy compound, cyclohexanedimethanols are particularly preferable, and 1,4-cyclohexanedimethanol and 1,3-cyclohexane are preferable from the viewpoint of easy availability and handling. Dimethanol or 1,2-cyclohexanedimethanol is preferred. Of these, 1,4-cyclohexanedimethanol is preferred from the viewpoint of improving polymerization reactivity and toughness.

In the method for producing a polycarbonate resin of the present invention, a dihydroxy compound represented by the general formula (6) can be used as a raw material monomer.

In the general formula (6), R ₁₁ represents a chain alkylene group having 2 to 20 carbon atoms.

The dihydroxy compound represented by the general formula (6) may be linear or branched, but is preferably a linear alkylene diol. Specific examples include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,5-pentanediol, and 1,6-hexanediol.

Of these, 1,3-propylene glycol, 1,4-butanediol, and 1,6-hexanediol are preferable. When the molecular weight is small, 1,6-hexanediol is most preferred because it volatilizes during polymerization or the effect of imparting toughness is small.

In the method for producing the polycarbonate resin of the present invention, a bisphenol compound may be used as a raw material monomer. Examples of the bisphenol compound include 2,2-bis (4-hydroxyphenyl) propane [= bisphenol A], 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane, and 2,2-bis. (4-hydroxy-3,5-diethylphenyl) propane, 2,2-bis [4-hydroxy- (3,5-diphenyl) phenyl] propane, 2,2-bis (4-hydroxy-3,5-dibromo Phenyl) propane, 2,2-bis (4-hydroxyphenyl) pentane, 2,4′-dihydroxy-diphenylmethane, bis (4-hydroxyphenyl) methane, bis (4-hydroxy-5-nitrophenyl) methane, 1, 1-bis (4-hydroxyphenyl) ethane, 3,3-bis (4-hydroxyphenyl) pentane, 1,1-bis ( -Hydroxyphenyl) cyclohexane, bis (4-hydroxyphenyl) sulfone, 2,4'-dihydroxydiphenylsulfone, bis (4-hydroxyphenyl) sulfide, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxy-3, Examples include 3'-dichlorodiphenyl ether and 4,4'-dihydroxy-2,5-diethoxydiphenyl ether.

The polycarbonate resin in the present invention includes a dihydroxy compound having a site represented by the general formula (3), a dihydroxy compound represented by the general formula (4), a dihydroxy compound represented by the general formula (5), One or more dihydroxy compounds selected from the group consisting of the dihydroxy compound represented by the general formula (6) and the bisphenol compound, the total of them being 25 mol% or more when the total dihydroxy compound is 100 mol% It is preferable that it is obtained by using, More preferably, it is 30 mol% or more, More preferably, it is 35 mol% or more. Moreover, it is preferable that it is 82 mol% or less, More preferably, it is 75 mol% or less.

These dihydroxy compounds having a site represented by the general formula (3), dihydroxy compounds represented by the general formula (4), dihydroxy compounds represented by the general formula (5), and general formula (6) When the amount of one or more dihydroxy compounds selected from the group consisting of dihydroxy compounds and bisphenol compounds is too small, the toughness of the obtained polycarbonate resin is reduced, making pelletization or film formation difficult. There is a possibility. On the other hand, if the amount is too large, the obtained polycarbonate resin may not exhibit the desired optical performance.

Among these, in the present invention, from the viewpoint of optical properties, heat resistance, toughness of the obtained polymer and fluidity upon melting, the dihydroxy compound represented by the general formula (1) is 9,9-bis ( 4-Hydroxy-3-methylphenyl) fluorene and / or 9,9-bis (4- (2-hydroxyethoxy) phenyl) fluorene are preferred. Moreover, as a dihydroxy compound represented by the said Formula (4), the polycarbonate resin which copolymerized isosorbide and / or spiroglycol is preferable.

Further, for imparting toughness, at least one dihydroxy compound selected from diethylene glycol, triethylene glycol, polyethylene glycol, 1,4-cyclohexanedimethanol and 1,6-hexanediol is used, and three or more monomers are used. It is preferable to use a polycarbonate resin obtained by copolymerizing.

Particularly preferably, in addition to 9,9-bis [4- (2-hydroxyethoxy) phenyl] fluorene and isosorbide, diethylene glycol, triethylene glycol, polyethylene glycol, 1,4-cyclohexanedimethanol or 1,6-hexanediol is used. It is a polycarbonate resin obtained by copolymerizing at least one dihydroxy compound selected from the group of 30 mol% or less, more preferably 20 mol% or less.

The polycarbonate resin in the present invention can be obtained by interfacial polycondensation using the dihydroxy compound and phosgene. In particular, as a dihydroxy compound, when m = n = 0 or a bisphenol compound is used among the compounds represented by the general formula (1), an aqueous solution of an alkali metal salt of a dihydroxy compound and phosgene are chlorinated. It is preferably obtained by an interfacial polycondensation method in which the reaction is carried out in the presence of a solvent such as methylene.

In addition, when the dihydroxy compound has a structure having no phenolic hydroxyl group, that is, the compound represented by the general formula (1), the compound having the site represented by the general formula (3) and / or the general formula. When the dihydroxy compound represented by (4), (5) or (6) is used in combination, the monohydroxy compound produced as a by-product by transesterifying the dihydroxy compound and the carbonic acid diester in the presence of a catalyst is removed from the system. It is preferable to obtain by a transesterification method in which the molecular weight is increased while removing.

The polycarbonate resin using the dihydroxy compound having the site represented by the general formula (3) or the dihydroxy compound represented by the general formula (4), (5), or (6) as a monomer component starts to decompose at a low temperature. When attempting to filter at a temperature that does not cause decomposition of the polycarbonate resin, the viscosity is too high, and the pressure loss at the filter becomes large at the normal filtration area, causing damage to the filter or during filtration. There was a problem that the resin was deteriorated by shearing heat generation. Conversely, in order to avoid breakage, a filter having a small pressure loss and low filtration accuracy (a large opening) had to be used.

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

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

These problems are likely to occur when a dihydroxy compound having a site represented by the general formula (3), particularly a dihydroxy compound having a cyclic ether structure, is used as a monomer component.

Therefore, when the dihydroxy compound having the site represented by the general formula (3) or the dihydroxy compound represented by the general formula (4), (5) or (6) is used as a monomer component, a filter is used. Therefore, it is important to control the temperature of the resin during filtration, and the present invention is particularly useful.

(Carbonated diester)
Examples of the carbonic acid diester used in the present invention include those represented by the following general formula (11). 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.

A ¹ and A ² are preferably a substituted or unsubstituted aromatic hydrocarbon group, more preferably an unsubstituted aromatic hydrocarbon group. Examples of the substituent of the aliphatic hydrocarbon group include an ester group, an ether group, a carboxylic acid, an amide group, and a halogen. Examples of the substituent of the aromatic hydrocarbon group include alkyl groups such as a methyl group and an ethyl group.

Examples of the carbonic acid diester represented by the general formula (11) include substituted diphenyl carbonates such as diphenyl carbonate and ditolyl carbonate, dimethyl carbonate, diethyl carbonate, and di-t-butyl carbonate. Among these, diphenyl carbonate or substituted diphenyl carbonate is 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 polycondensing a dihydroxy compound containing the dihydroxy compound of the present invention and a carbonic acid diester by a transesterification reaction.

The raw material dihydroxy compound and carbonic acid diester can be transesterified even if they are dropped independently into the reaction tank, but they can be mixed uniformly before the transesterification.

The mixing temperature is preferably 80 ° C. or higher, more preferably 90 ° C. or higher, and the upper limit is preferably 250 ° C. or lower, more preferably 200 ° C. or lower, still 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 may be deteriorated.

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%, It is preferably performed in an atmosphere of 0.0001 vol% to 5 vol%, particularly preferably 0.0001 vol% to 1 vol%, from the viewpoint of preventing hue deterioration.

In the present invention, the carbonic acid diester is preferably used in a molar ratio of 0.90 to 1.20, more preferably 0.95 to 1.20, based on all dihydroxy compounds including the dihydroxy compound of the present invention used in the reaction. 10, more preferably 0.97 to 1.03, particularly preferably 0.99 to 1.02.

When the molar ratio is decreased, the terminal hydroxyl group of the produced polycarbonate resin is increased, the thermal stability of the polymer is deteriorated, coloring is caused at the time of molding, the rate of the transesterification reaction is decreased, and the desired high molecular weight. The body may not be obtained.

On the other hand, when the molar ratio increases, the rate of transesterification decreases, the production of polycarbonate having a desired molecular weight becomes difficult, the amount of residual carbonic diester in the polycarbonate resin increases, and during extrusion or molding In some cases, gas may be generated. The decrease in the transesterification reaction rate may increase the thermal history during the polymerization reaction and may deteriorate the hue of the resulting polycarbonate resin.

Furthermore, when the molar ratio of the carbonic diester is increased with respect to all the dihydroxy compounds including the dihydroxy compound of the present invention, the amount of residual carbonic diester in the obtained polycarbonate resin increases, which becomes a gas at the time of molding and causes molding defects. Bleed out from the product, which is not preferable.

The concentration of the carbonic acid diester remaining in the polycarbonate resin pellet or film obtained by the method of the present invention is preferably 200 ppm by weight or less, more preferably 100 ppm by weight or less, still more preferably 60 ppm by weight or less, and particularly 30 ppm by weight or less. preferable.

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

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

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

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, Potassium carbonate, lithium carbonate, cesium carbonate, sodium acetate, potassium acetate, lithium acetate, cesium acetate, sodium stearate, potassium stearate, lithium stearate, cesium stearate, sodium borohydride, potassium borohydride, borohydride Lithium, cesium borohydride, sodium borohydride, potassium phenyl borohydride, lithium phenyl borohydride, cesium phenyl borohydride, sodium benzoate, potassium benzoate, lithium benzoate, cesium benzoate, 2 sodium hydrogen phosphate, 2 potassium hydrogen phosphate, 2 lithium hydrogen phosphate, 2 cesium hydrogen phosphate, 2 sodium phenyl phosphate, 2 potassium phenyl phosphate, 2 lithium phenyl phosphate, 2 cesium phenyl phosphate, sodium, Examples thereof include potassium, lithium, cesium alcoholate, phenolate, disodium salt of bisphenol A, 2 potassium salt, 2 lithium salt, and 2 cesium salt. Of these, 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, and carbonic acid. Examples thereof include calcium, barium carbonate, magnesium carbonate, strontium carbonate, calcium acetate, barium acetate, magnesium acetate, strontium acetate, calcium stearate, barium stearate, magnesium stearate, and strontium stearate.

Among them, a magnesium compound, a calcium compound or a barium compound is preferable, and at least one metal compound selected from the group consisting of a magnesium compound and a calcium compound is more preferable from the viewpoint of polymerization activity and the hue of the obtained polycarbonate resin, most preferably magnesium. A compound.

In addition, a basic compound such as a basic boron compound, a basic phosphorus compound, a basic ammonium compound, or an amine compound can be used in combination with the Group 1 metal compound and / or the Group 2 metal compound. However, it is particularly preferable to use only the Group 1 metal compound and / or the Group 2 metal compound because it may volatilize during the polymerization reaction and cause trouble.

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 and strontium such as phenylboron, tributylbenzylboron, tributylphenylboron, tetraphenylboron, benzyltriphenylboron, methyltriphenylboron and butyltriphenylboron Examples include salts.

Examples of the basic phosphorus compound that can be used in combination include triethylphosphine, tri-n-propylphosphine, triisopropylphosphine, tri-n-butylphosphine, triphenylphosphine, tributylphosphine, and quaternary phosphonium salts. .

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 Phenyl Nmo onium hydroxide and butyltriphenyl ammonium hydroxide, and the like.

Examples of the amine compounds 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, more preferably 0.5 μmol to 100 μmol, still more preferably 0.5 μmol to 50 μmol, and particularly preferably 0.5 μmol to 20 μmol per 1 mol of all dihydroxy compounds used. Most preferably, it is 1 μmol to 15 μmol.

In particular, when using at least one metal compound selected from the metals of Group 2 of the long-period periodic table and lithium, the amount of metal is preferably usually 0.1 μmol or more per 1 mol of all dihydroxy compounds used, Preferably it is 0.5 micromol or more, More preferably, it is 0.7 micromol or more. The upper limit is usually preferably 50 μmol, more preferably 30 μmol, still more preferably 20 μmol, particularly preferably 15 μmol, and particularly preferably 10 μmol.

If the amount of the catalyst used is too small, the polycondensation reaction will not proceed easily, and a polycarbonate resin having a desired molecular weight may not be obtained. On the other hand, if the amount of the catalyst used is too large, the hue of the polycarbonate resin obtained by an undesired side reaction may be deteriorated or foreign matter may be caused.

In addition, when a large amount of Group 1 metal, especially sodium, is contained in the polycarbonate resin, the hue may be adversely affected, and the metal may be mixed not only from the catalyst used but also from the raw material or the reactor. Therefore, the total amount of these compounds in the polycarbonate resin is usually preferably 1 ppm by weight or less, more preferably 0.8 ppm by weight or less, and even more preferably 0.7 ppm by weight or less as the amount of metal. .

The amount of metal in the polycarbonate resin can be measured using a method such as atomic emission, atomic absorption, or 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.

(Polycondensation method by transesterification)
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 reaction format may be any of batch, continuous, or a combination of batch and continuous. Among these, the continuous type is preferable from the viewpoint of stabilizing the quality. In the initial stage of polymerization, it is preferable to obtain a prepolymer at a relatively low temperature and low vacuum, and to increase the molecular weight to a predetermined value at a relatively high temperature and high vacuum in the late stage of polymerization.

It is preferable from the viewpoints of hue and thermal stability that the jacket temperature and internal temperature at each molecular weight stage and the pressure in the reaction system are appropriately selected. For example, if either the temperature or the pressure is changed too quickly before the polymerization reaction reaches a predetermined value, unreacted monomers 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 monomer to be distilled off, and the effect is particularly great in a reactor in the early 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.

Usually, the temperature of the refrigerant introduced into the reflux condenser is preferably 45 to 180 ° C. at the inlet of the reflux condenser, more preferably 80 to 150 ° C., and particularly preferably 100 to 140 ° C.

If the temperature of the refrigerant is too high, the amount of reflux is reduced 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 be reduced. 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 or thermal stability, Selection of type and quantity is important.

In the present invention, it is preferable that the catalyst is used for polymerization in multiple stages using a plurality of reactors. In the initial stage of the polymerization reaction, since a large amount of monomer is contained in the reaction solution, it is preferable to suppress the volatilization of the monomer while maintaining a necessary polymerization rate. In the latter stage of the polymerization reaction, it is preferable to sufficiently distill off the by-produced monohydroxy compound in order to shift the equilibrium to the polymerization side. Therefore, since preferable polymerization reaction conditions are different between the initial stage and the late stage, it is preferable to carry out the polymerization in a plurality of reactors. 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 is preferably at least two, more preferably three or more, and still more preferably 3 to 5 from the viewpoint of production efficiency. And particularly preferably 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 or 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. The catalyst supply pipe is preferably installed in the middle of the raw material pipe before being supplied, and more preferably supplied as an aqueous solution.

If the temperature of the polymerization reaction is too low, the productivity is lowered or the thermal history of the product is increased. If the temperature is too high, not only the monomer is volatilized but also decomposition or coloring of the polycarbonate resin may be promoted. .

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., more preferably 170 to 240 ° C., still more preferably 180 to 210 ° C., and preferably 110 to 1 kPa, More preferably 70 to 5 kPa, still more preferably 30 to 10 kPa (absolute pressure), preferably 0.1 to 10 hours, more preferably 0.5 to 3 hours. It is carried out while distilling off.

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. Preferably it is 2 kPa or less, more preferably 1 kPa or less, preferably 210 ° C. or more, more preferably 220 ° C. or more, preferably 270 ° C. or less, more preferably 250 ° C. or less, still more preferably 240 ° C. or less, preferably 0 1 to 10 hours, more preferably 1 to 6 hours, particularly preferably 0.5 to 3 hours.

In particular, in order to suppress the coloring or thermal deterioration of the polycarbonate resin and obtain a polycarbonate resin having a good hue or thermal stability, the maximum internal temperature in all reaction steps is preferably 260 ° C. or less, more preferably 250 ° C. or less, Especially preferably, it is 245 degrees C or less, Especially it is preferable that it is 240 degrees C or less.

Here, the internal temperature indicates 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 is necessary to note that the yellow index (YI) value representing the hue tends to increase when the polymerization temperature is increased and the polymerization time is excessively prolonged.

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

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

Examples of the method for pelletizing the polycarbonate resin obtained by polycondensation as described above by using a filter include the following methods.

For example, in order to generate a pressure required for filtration, a method of extracting polycarbonate resin in a molten state from a final polymerization reactor using a gear pump or a screw and filtering with the filter;
Polycarbonate resin is supplied from a final polymerization reactor to a uniaxial or biaxial extruder in a molten state, melt extruded, filtered through the filter, cooled and solidified in the form of a strand, and pelletized with a rotary cutter or the like. Method;
Polycarbonate resin is supplied to a single-screw or twin-screw extruder in a molten state without being solidified from the final polymerization reactor, melt-extruded, then cooled and solidified in the form of a strand, pelletized, and the pellet is extruded again. A method of introducing into a machine, filtering with the filter, cooling and solidifying in the form of a strand, and pelletizing;
Alternatively, the polycarbonate resin is extracted from the final polymerization reactor in a molten state, cooled and solidified in the form of strands without passing through an extruder, and once pelletized, then the pellets are supplied to a single or twin screw extruder and melted. A method of extruding, filtering through the filter, cooling and solidifying in the form of a strand, and pelletizing;
Etc.

In particular, in order to minimize heat history and suppress thermal degradation such as deterioration of hue or molecular weight, the resin is put into a single or twin screw extruder in a molten state without solidifying from the final polymerization reactor. A method of feeding, melting and extruding, feeding to the filter using a gear pump, filtering, discharging from a die, cooling and solidifying in the form of a strand, and pelletizing with a rotary cutter or the like is preferable.

<Example of manufacturing equipment>
An example of an apparatus for carrying out the present invention for obtaining polycarbonate resin pellets obtained by cooling and solidification from the raw material monomers described above (hereinafter, “cooled and solidified polycarbonate resin” may be simply referred to as “polycarbonate resin”). Is shown in the process diagram of FIG.

9,9-bis [4- (2-hydroxyethoxy) phenyl] fluorene and isosorbide (ISB) are used as the raw material monomer of the present invention, diphenyl carbonate (DPC) is used as the carbonic acid diester, and magnesium acetate is used as the polymerization catalyst. Shall be used.

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 9,9-bis [4- (2-hydroxyethoxy) phenyl] fluorene powder weighed under a nitrogen gas atmosphere are fed from the raw

material supply ports

1b and 1c, respectively, into the raw material mixing tank. 2a is continuously supplied. And these are mixed by the stirring blade 3a in the raw material mixing tank 2a, and a uniform raw material mixing melt is obtained.

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

In the polycondensation step of the production apparatus of FIG. 1, a first vertical stirring reaction tank 6a, a second vertical stirring reaction tank 6b, a third vertical stirring reaction tank 6c, and a fourth horizontal stirring reaction tank 6d are provided in series. It is done. In each reactor, the liquid level is kept constant, the polycondensation reaction is continuously performed, and the polymerization reaction liquid discharged from the bottom of the first vertical stirring reaction tank 6a is transferred to the second vertical stirring reaction tank 6b. Subsequently, the third vertical stirring reaction tank 6c and the fourth horizontal stirring reaction tank 6d are sequentially and continuously supplied, 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.

Max blend blades

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

In the first vertical stirring reaction tank 6a and the second vertical stirring reaction tank 6b, the amount of supplied heat may be particularly large, so that the

internal heat exchangers

8a and 8b are respectively provided so that the heat medium temperature does not become excessively high. Is provided.

In addition, distilling

tubes

11a, 11b, 11c, and 11d for discharging by-products generated by the polycondensation reaction are attached to these four reactors, respectively. For the first vertical stirring reaction tank 6a and the second vertical stirring reaction tank 6b,

reflux condensers

9a and 9b and

reflux pipes

10a and 10b are provided in order to return a part of the distillate to the reaction system. The reflux ratio can be controlled by appropriately adjusting the pressure of the reactor and the heat medium temperature of the reflux condenser.

The

distillation pipes

11a, 11b, 11c, and 11d are connected to

condensers

12a, 12b, 12c, and 12d, respectively, and each reactor is in a predetermined depressurized state by a

decompression device

13a, 13b, 13c, and 13d. To be kept.

Further, by-products such as phenol (monohydroxy compound) are continuously liquefied and recovered from the

condensers

12a, 12b, 12c, and 12d attached to the respective reactors. Further, a cold trap (not shown) is provided downstream of the

condensers

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

The reaction liquid raised to a predetermined molecular weight is withdrawn from the fourth horizontal stirring reaction tank 6d, and the pipe connecting the extruder 15a by the gear pump 4c is a jacket-type double pipe in which the heat medium flows to the outside. preferable.

The temperature of the heating medium can be appropriately determined in consideration of the viscosity of the polycarbonate resin, the pressure loss of the piping, and the thermal stability of the polycarbonate resin. However, if the temperature is too high, the polycarbonate resin may be deteriorated or gas may be generated. Usually, it is preferably 300 ° C. or lower, more preferably 280 ° C. or lower, further preferably 260 ° C. or lower, particularly preferably 250 ° C. or lower, and particularly preferably 240 ° C. or lower.

On the other hand, if the temperature of the heating medium is too low, the pressure loss in the piping becomes large and the piping diameter needs to be increased, but at the same time, the residence time in the piping of the polycarbonate resin becomes long and may cause thermal deterioration. Therefore, it is usually preferably 150 ° C. or higher, more preferably 180 ° C. or higher, further preferably 200 ° C. or higher, particularly preferably 210 ° C. or higher, and particularly preferably 220 ° C. or higher.

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, or the like is 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 the form of a strand from the die 15c, and after cooling and solidifying the resin with water in the strand cooling tank 16a, the resin is 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.

There are no restrictions on the types of gear pumps 4c and 4d, but there is a circuit that leads a part of the polymer from the discharge side of the gear pump to the ground through the valve, applies a certain pressure to the shaft seal, and returns it to the suction port. A self-circulating seal type gear pump that does not use a gland packing at the seal portion is preferable from the viewpoint of reducing foreign matter.

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

In addition, in the polycarbonate resin obtained by polycondensation as described above, hue or thermal stability, and further, raw material monomers that may adversely affect the product due to bleed-out, etc. Low molecular weight compounds such as hydroxy compounds or polycarbonate oligomers often remain.

It is also possible to devolatilize and remove the low molecular weight compound by using an extruder having a vent port and preferably reducing the pressure from the vent port using a vacuum pump or the like. Moreover, volatile liquids, such as water, can be introduce | transduced in the said extruder, and devolatilization can also be accelerated | stimulated. The number of vent ports may be one or plural, but preferably two or more.

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

Furthermore, 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 preferably 300 rpm or less, more preferably 250 rpm or less, More preferably, it is 200 rpm or less. By setting the number of rotations of the screw to 300 rpm or less, it is possible to suppress an increase in shear heat generation of the polycarbonate resin, and to prevent a deterioration in hue or a decrease in molecular weight.

On the other hand, if the number of rotations of the screw is too small, not only may the devolatilization performance deteriorate, or the additive kneading performance deteriorates, but the throughput per unit time decreases, resulting in deterioration of 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 rotational speed of the extruder, but in order to suppress thermal deterioration such as coloring or molecular weight reduction due to heat generated by shearing of the polycarbonate resin, Usually, it is preferably 1.0 m / second or less, more preferably 0.6 m / second or less, and particularly preferably 0.4 m / second or less.

On the other hand, if the peripheral speed becomes too small, venting up during vacuum devolatilization tends to occur, or devolatilization performance or additive dispersion performance tends to decrease. Therefore, it is usually preferably 0.05 m / second or more. More preferably, it is 0.1 m / second or more.

Usually, the screw of the extruder is composed of a plurality of elements (screw elements) in order to have various functions. Generally, it consists of a full flight consisting mainly of spiral screws (flight) for the purpose of transporting the resin, a kneading disc for the purpose of resin kneading, or a seal ring for the purpose of resin sealing. . Depending on the purpose, a reverse flight in which screws are arranged in the direction opposite to the direction of resin conveyance is also used.

Also, depending on how the screw is cut, there are two-row type or three-row type, but in the present invention, a double-row deep groove capable of taking a large amount of processing with respect to the screw diameter of the extruder and suppressing shearing heat generated by screw rotation. Type is preferred.

In the present invention, the configuration of these screw elements is not limited, but it is preferable to have a kneading disk. Among them, the total length of the kneading disk is 20% of the total length of the screw. % Or less, more preferably 15% or less, and most preferably 10% or less. If the total length of the kneading disk is too long, local heat generation due to the shearing of the resin increases, and the problem of deterioration of the hue or molecular weight of the polycarbonate resin tends to occur.

On the other hand, if the total length of the kneading disk is too short, the performance during devolatilization or kneading of the additive may be deteriorated. It is preferably 3% or more of the length, and more preferably 5% or more.

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

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

In the present invention, when the weight of the resin extruded per hour by the extruder is W (kg / h) and the sectional area of the barrel of the extruder is S (m ² ), the following formula (7) is satisfied. It is preferable to satisfy.
12000 ≦ W / S ≦ 60000 (7)

If W / S is too small, not only will the size of the extruder be excessive with respect to the amount of polycarbonate resin to be processed, but also the residence time in the extruder will increase, resulting in a decrease in molecular weight or deterioration of the coloring of the polycarbonate resin. The lower limit is preferably 12000, more preferably 15000, still more preferably 20000, and particularly preferably 25000.

On the other hand, if it is too large, an excessively large polycarbonate resin is supplied with respect to the size of the extruder, which may lead to a decrease in devolatilization efficiency and deterioration of the polycarbonate resin due to shearing heat generation. Therefore, the upper limit is preferably 60000, More preferably, it is 50000, still more preferably 40000, and particularly preferably 35000.

In the present invention, the temperature of the resin when the polycarbonate resin is supplied in the molten state to the extruder is preferably 200 ° C. or higher, and particularly preferably 210 ° C. or higher, particularly 220 ° C. or higher. Further, the upper limit is preferably 250 ° C. or lower, more preferably 245 ° C. or lower, particularly 240 ° C. or lower.

If the temperature of the polycarbonate resin supplied to the extruder is too low, the melt viscosity of the polycarbonate resin becomes too high and the supply becomes unstable, and the load on the drive motor of the extruder becomes excessive. In addition to the possibility of not being able to satisfy, there is a possibility that the shear heat generation in the extruder becomes large and the polycarbonate resin is deteriorated. On the other hand, when the temperature is too high, the polycarbonate resin is likely to be deteriorated, which tends to cause a deterioration in hue, a decrease in molecular weight, or a decrease in mechanical strength associated therewith.

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

Furthermore, in the present invention, the temperature of the polycarbonate resin discharged from the extruder is usually preferably less than 300 ° C, more preferably less than 280 ° C, still more preferably less than 270 ° C, particularly preferably 260 ° C. Is less than.

If the temperature of the polycarbonate resin discharged from the extruder becomes too high, the polycarbonate resin tends to be deteriorated, which tends to cause a deterioration in hue or a decrease in molecular weight, and a decrease in mechanical strength associated therewith.

Conversely, if the temperature of the polycarbonate resin discharged from the extruder becomes too low, the melt viscosity of the polycarbonate resin is high, the load on the extruder increases, screw rotation becomes unstable, and the motor is overloaded. Therefore, it is preferably 220 ° C. or higher, more preferably 230 ° C. or higher, and particularly preferably 240 ° C. or higher.

Usually, in an extruder, heat is generated by shearing of the resin accompanying the rotation of the screw, and generally the temperature of the discharged polycarbonate resin tends to be higher than the temperature of the supplied polycarbonate resin. This tendency becomes significant when the molecular weight is high and the melt viscosity is high.

If the temperature of the polycarbonate resin is raised, the melt viscosity will decrease, and the shearing heat generation will tend to be suppressed accordingly.However, if the temperature of the polycarbonate resin itself is high, the deterioration tends to occur, the hue deteriorates or the molecular weight decreases, or it accompanies it. Since there is a tendency to cause a decrease in mechanical strength, it is not easy to perform extrusion by preventing deterioration of a polycarbonate resin having high viscosity that is inferior in thermal stability.

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

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

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

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

The 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 50 μm or less, preferably 30 μm or less, more preferably 20 μm or less, as 99% filtration accuracy. When it is desired to reduce foreign matters, the thickness is preferably 15 μm or less. However, if the aperture is reduced, the pressure loss in the filter may increase, and the filter may be damaged, or the polycarbonate resin may be deteriorated by shearing heat generation. Therefore, the filtration accuracy of 99% is preferably 1 μm or more.

Here, the aperture defined as 99% filtration accuracy is the value of χ when the βχ value represented by the following formula (12) determined in accordance with ISO 16889 (2008) is 100. To tell.
βχ = (number of particles on the primary side larger than χ μm) / (number of particles on the secondary side larger than χ μm) (12)
(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 necessary for resin filtration, but stainless steel such as SUS316 or SUS316L with a low iron content is particularly preferable.

Also, as the type of weaving, a nonwoven fabric type can be used in addition to a regular weaving part of the foreign matter such as plain weave, twill weave, plain tatami mat or twill mat weave. In the present invention, a non-woven fabric type having a high gel-capturing ability, particularly a type in which steel wires constituting the non-woven fabric are sintered and fixed is preferable.

In 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.

As the passivation treatment, for example, 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 passivated surface, and roasting is performed in the presence of water vapor or oxygen. The method of (heating) processing, the method of using these together, etc. are mentioned. Among them, it is preferable to perform both nitric acid treatment and roasting.

The temperature when the filter is roasted is preferably 350 ° C. to 500 ° C., more preferably 350 ° C. to 450 ° C., and the roasting time is usually preferably 3 hours to 200 hours, More preferably, it is 5 hours to 100 hours.

If the roasting temperature is too low or the time is too short, the formation of passivity is insufficient, and the polycarbonate resin tends to deteriorate during filtration. On the other hand, if the temperature of roasting is too high or the time is too long, the filter media may be severely damaged and the required filtration accuracy may not be achieved.

Further, the concentration of nitric acid when the filter is treated with nitric acid is usually preferably 5 to 50% by weight, more preferably 10 to 30% by weight, and the temperature during the treatment is usually 5 ° C. It is preferably from -100 ° C, more preferably from 50 ° C to 90 ° C, and the treatment time is usually preferably from 5 minutes to 120 minutes, more preferably from 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 containment vessel because it facilitates filtration under pressure while securing a necessary filtration area. The material of the storage container 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 will be deteriorated during filtration, so it is preferably 1 minute to 20 minutes, more preferably 2 minutes to 10 minutes, and more preferably 3 to 8 minutes.

In the present invention, the linear velocity of the molten resin on the filter surface is preferably 0.01 to 0.5 m / h. The linear velocity of the molten resin on the filter surface can be determined by dividing the processing volume of polycarbonate resin per hour by the filtration area of the filter. If the linear velocity is excessively low, the residence time during filtration may be prolonged, leading to deterioration of the polycarbonate resin, which may cause coloring or foreign matter generation.

Further, if the linear velocity is excessively high, shear heat generation during filtration increases, which may cause coloring or generation of foreign matter. Therefore, it is more preferably 0.03 to 0.3 m / h, particularly preferably. 0.05 to 0.15 m / h.

In the method of the present invention, the temperature of the polycarbonate resin supplied to the filter is usually preferably less than 300 ° C, more preferably less than 280 ° C, further preferably less than 270 ° C, and particularly preferably 265 ° C. Less than 260.degree.

If the temperature before filtering with the filter becomes too high, thermal deterioration in the filter unit is likely to occur, and there is a tendency to cause deterioration in hue or molecular weight, or mechanical strength associated therewith.

Conversely, if the temperature before filtering with the filter is too low, the melt viscosity of the polycarbonate is high and the load on the filter increases, which may cause damage to the filter. The temperature of the polycarbonate resin is preferably 220 ° C. or higher, more preferably 230 ° C. or higher, particularly preferably 240 ° C. or higher.

In the present invention, the temperature of the polycarbonate resin after filtration is 200 ° C. or higher, preferably 220 ° C. or higher, more preferably 230 ° C. or higher. If the temperature of the polycarbonate resin after filtration using the filter is too low, the melt viscosity becomes high and the extruded strands are not stable and tend to be difficult to be pelletized with a rotary cutter or the like. There is.

On the other hand, the temperature of the polycarbonate resin after filtration is less than 280 ° C, preferably less than 270 ° C, more preferably less than 265 ° C, and still more preferably less than 260 ° C. If the temperature of the polycarbonate resin after filtration using the filter is too high, the polycarbonate resin is likely to be thermally deteriorated, which tends to cause a deterioration in hue, a molecular weight, or a mechanical strength associated therewith.

Examples of the resin temperature after the filtration include a method in which the resin discharged from the filter is taken out and directly measured, and a method in which a sensor is installed inside the pipe of the filter outlet channel and the like.

When measuring with the sensor installed inside the pipe of the filter outlet channel, it may be difficult to measure the correct resin temperature due to the influence of the heater installed outside the pipe around the sensor. If a device that discharges resin such as a die is installed near the filter outlet and the temperature of the resin discharged from the device can be regarded as equivalent to the resin temperature on the filter outlet side, The temperature of the discharged resin may be the resin temperature after filtration according to the present invention.

For the purpose of increasing the accuracy of the resin temperature after filtration, a sensor is installed inside the pipe of the filter outlet channel, and the temperature of the resin discharged from a die installed near the filter outlet is measured. Both methods can also be implemented.

In the method of the present invention, the filter unit is usually provided with a heater composed of a plurality of blocks on the outside thereof for temperature control, but if the set temperature is too high, the polycarbonate resin may be deteriorated. It is set to 280 ° C. or lower, more preferably 260 ° C. or lower, particularly preferably 250 ° C. or lower.

On the other hand, if the set temperature is too low, the melt viscosity becomes high and it is difficult to filter with a filter. Therefore, it is usually preferably 150 ° C. or higher, more preferably 180 ° C. or higher, particularly preferably 200 ° C. or higher.

Also, a pipe for guiding the polycarbonate resin discharged from the filter unit to the die is usually provided with a heater outside thereof, but since the polycarbonate resin may be deteriorated if its set temperature is too high, it is usually preferable. It is set to 280 ° C. or lower, more preferably 260 ° C. or lower, particularly preferably 250 ° C. or lower.

On the other hand, if the set temperature is too low, the melt viscosity becomes high and the pressure loss in the piping increases, so that it is usually preferably 150 ° C. or higher, more preferably 180 ° C. or higher, and particularly preferably 200 ° C. or higher.

Further, if the residence time of the polycarbonate resin from the outlet of the filter unit to the die is long, the polycarbonate resin may be deteriorated. Therefore, it is usually preferably 1 to 30 minutes, more preferably 3 to 20 minutes.

In the method of the present invention, the temperature of the polycarbonate resin discharged from the die through filtration with the filter is preferably 200 ° C. or higher, more preferably 220 ° C. or higher, further preferably 230 ° C. or higher, The upper limit is preferably less than 280 ° C, more preferably less than 270 ° C, even more preferably less than 265 ° C, and particularly preferably less than 260 ° C.

If the temperature of the polycarbonate resin discharged from the die after filtration is too low, the melt viscosity becomes high and the extruded strands are not stable and may be difficult to pelletize with a rotary cutter or the like There is sex. On the other hand, if the temperature is too high, thermal degradation of the polycarbonate resin is likely to occur, which may lead to a deterioration in hue, a decrease in molecular weight, or a decrease in mechanical strength associated therewith.

Usually, a heater is installed in the die, but if the set temperature is too high, the polycarbonate resin may be deteriorated. Therefore, the temperature is usually preferably 280 ° C. or less, more preferably 260 ° C. or less, particularly preferably. Set to 250 ° C or lower.

Normally, when polycarbonate resin is filtered through the above-mentioned filter having a small mesh opening, the temperature rises due to shearing heat generation, and when using an extruder, shearing heat generation due to screw rotation is also added, so the polycarbonate discharged from the die through filtration To control the temperature of the resin, it is important to comprehensively control the opening of the filter, the filtration area, the temperature setting, the molecular weight of the polycarbonate resin, the temperature setting of the filter unit or the temperature setting from the filter outlet to the die, etc. become.

In addition, when the extruder is used for supplying to the filter, the processing amount of the polycarbonate resin in the extruder, the rotational speed or peripheral speed of the screw, or the configuration of the element or the like can be selected as described above. Become important.

In the method of the present invention, the difference between the temperature of the polycarbonate resin before being filtered by the filter and the temperature of the polycarbonate resin after the filtration is preferably within 50 ° C, more preferably within 30 ° C, most preferably Preferably it is within 10 degreeC.

When the temperature difference between the temperature of the polycarbonate resin before being filtered by the filter and the temperature of the polycarbonate resin after the filtration becomes too large, particularly when a filter unit is constituted by a plurality of leaf disk filters, the resin supply side and The pressure balance may be lost on the discharge side, and the filter may be damaged.

In the method of the present invention, the reduced viscosity (ηsp / c) of the polycarbonate resin obtained by polycondensation by the transesterification reaction before being filtered through the filter is filtered using the filter A and the die is obtained. When the reduced viscosity (ηsp / c) of the polycarbonate resin pellets obtained by discharging in the form of strands and cooling and using a cutter after cooling is B, it is preferable to satisfy the following formula (2).
0.8 <B / A <1.1 (2)

More preferably, B / A> 0.85, still more preferably B / A> 0.9, and particularly preferably B / A> 0.95. By setting B / A to more than 0.8, it is possible to suppress the generation of a coloring component or a coloring precursor that is considered to be generated by a side reaction, which is preferable. On the other hand, when the reduced viscosity rises in the polymer filter, the generation of foreign matters such as gel or burnt rises, and therefore it is more preferable that B / A ≦ 1.0. A method for measuring the reduced viscosity will be described later.

When the extruder is installed between the polycondensation reactor and the filter, when the reduced viscosity (ηsp / c) of the polycarbonate resin supplied to the extruder is a, For B, it is preferable to satisfy the following formula (8).
0.8 <B / a <1.1 (8)

More preferably, B / a> 0.85, and particularly preferably B / a> 0.9. By setting B / a to more than 0.8, it is possible to suppress the generation of a coloring component or a coloring precursor that is considered to be generated by a side reaction, which is preferable. On the other hand, when the reduced viscosity is increased, the generation of foreign matters such as gels or burns rises. Therefore, it is more preferable that B / a ≦ 1.0.

In order to make the change in the reduced viscosity in the polymer filter or the extruder within the above range, the temperature of the polycarbonate resin in the final reactor, the temperature of the polycarbonate resin entering the polymer filter, the temperature of the polycarbonate resin discharged from the polymer filter, Selection of throughput per unit time or opening of polymer filter, temperature control or residence time from polymer filter to die, when using an extruder, temperature of polycarbonate resin supplied to the extruder, discharge from the extruder It is important to select the temperature of the polycarbonate resin to be used, the devolatilization pressure, the presence or absence of water injection, the amount of water injection, the rotation speed or peripheral speed of the screw, or the element configuration.

Furthermore, when the extruder is used, it is preferable to dispose a gear pump between the extruder and the filter in order to stabilize the supply amount of the polycarbonate resin to the filter. There is no restriction on the type of gear pump, but in particular, a part of polymer from the discharge side of the gear pump is guided to the gland part through the valve, a certain pressure is applied to the shaft seal part, and there is a circuit to return it to the suction port, and the seal A self-circulation type in which no gland packing is used for the part is preferable from the viewpoint of reducing foreign matter.

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

The polycarbonate resin filtered by the filter is cooled and solidified, and pelletized by a rotary cutter or the like, and it is preferable to use a cooling method such as air cooling or water cooling when pelletizing.

The air used for air cooling is preferably air from which foreign matter in the air has been removed in advance with a hepa filter or the like to prevent reattachment of foreign matter in the air. When water cooling is used, it is preferable to use water from which metal in water has been removed with an ion exchange resin or the like, and further, foreign matter in water has been removed with the filter. The opening of the filter to be used is preferably 10 to 0.45 μm in terms of filtration accuracy with 99.9% removal.

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

Among these, addition of a phosphite ester or a hindered phenol heat stabilizer is preferable because it can suppress a decrease in molecular weight or a deterioration in color tone during extrusion or filtration of the polycarbonate resin of the present invention.

Specific examples of the phosphite-based heat stabilizer include triphenyl phosphite, tris (nonylphenyl) phosphite, tris (2,4-di-tert-butylphenyl) phosphite, and tridecyl phosphite. Phyto, 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) pentaerythrityl diphosphite, 2,2-methylenebis (4,6-di-tert-butylphenyl) octyl phosphite, bis (nonylpheny ) Pentaerythrityl diphosphite, bis (2,4-di-tert-butylphenyl) pentaerythrityl diphosphite, distearyl pentaerythrityl diphosphite, tributyl phosphate, triethyl phosphate, trimethyl phosphate, triphenyl phosphate, Diphenyl monoorthoxenyl phosphate, dibutyl phosphate, dioctyl phosphate, diisopropyl phosphate, 4,4′-biphenylenediphosphinic acid tetrakis (2,4-di-tert-butylphenyl), benzene phosphonate dimethyl, benzenephosphonate diethyl and benzenephosphone Examples include dipropyl acid.

Among them, trisnonylphenyl phosphite, trimethyl phosphate, tris (2,4-di-tert-butylphenyl) phosphite, bis (2,4-di-tert-butylphenyl) pentaerythrityl diphosphite, bis ( 2,6-di-tert-butyl-4-methylphenyl) pentaerythrityl diphosphite or dimethylbenzenephosphonate is preferred, and tris (2,4-di-tert-butylphenyl) phosphite is more preferred.

Specific examples of the hindered phenol-based heat stabilizer include pentaerythrityl tetrakis (3-mercaptopropionate), pentaerythrityl tetrakis (3-laurylthiopropionate), glycerol-3-stearylthio. Propionate, 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], pentaerythrityltetrakis [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-butyl-4-hydroxybenzyl) benzene, N, N-hexamethylenebis (3,5-di-tert-butyl-4-hydroxy-hydro Cinnamide), 3,5-di-tert-butyl-4-hydroxy-benzylphosphonate-diethyl ester, tris (3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate, 4,4′-biphenylene Tetrakis (2,4-di-tert-butylphenyl) diphosphinate and 3,9-bis {1,1-dimethyl-2- [β- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyl Oxy] ethyl} -2,4,8,10-tetraoxaspiro (5,5) undecane and the like It is.

Among them, preferably pentaerythrityltetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] or octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) Propionate, particularly preferably pentaerythrityltetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate].

These heat stabilizers may be used alone or in combination of two or more. The blending amount of these heat stabilizers is preferably 0.0001 to 1 part by weight, more preferably 0.0005 to 0.5 part by weight, and 0.001 to 0.2 part, based on 100 parts by weight of the polycarbonate resin. Part by weight is more preferred.

(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, disk type, leaf disk type, tube type, flat cylindrical type, or pleated cylindrical type, among which compact and has a large filtration area. 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 preferred, and 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 or resin ceramics can be used. From the viewpoint of heat resistance and color reduction, a metal filter having an iron content of 80% or less. Among them, stainless steel such as SUS304, SUS316, SUS316L, or SUS310S is preferable.

Further, in order to extend the life of the raw material filtration filter while ensuring the filtration performance during the filtration of the raw material monomer, it is preferable to use a plurality of filter units, and in particular, the filter eyes in the upstream unit. In the case where the opening is C μm and the opening of the filter in the downstream unit is D μm, in at least one combination, C is preferably larger than D (C> D). 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 determined based on the above-mentioned ISO16889 (2008).

In the present invention, there is no restriction on the temperature of the raw material fluid when the raw material is passed through the raw material filtration filter, but if it is too low, the raw material is solidified, and if it is too high, there is a problem such as thermal decomposition. ˜200 ° C., more 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 90 or less, more preferably 70 or less, particularly preferably 50 or less, and most preferably 40 or less. In order to lower the yellow index value, as described above, it is necessary to appropriately select the monomer preparation conditions, the polymerization reaction conditions, the filtration conditions, and the extrusion conditions or screw elements when using an extruder.

Further, the molecular weight of the polycarbonate resin obtained in the method of the present invention can be represented by a reduced viscosity (ηsp / c), and the reduced viscosity is preferably 0.2 dL / g or more, more preferably 0.8. It is 25 dL / g or more, More preferably, it is 0.3 or more, It is preferable that it is 0.6 dL / g or less, More preferably, it is 0.5 dL / g or less, Most preferably, it is 0.45 dL / g or less.

If the reduced viscosity of the polycarbonate resin is too low, the mechanical strength of the molded product may be small, and if the stretching operation is performed after forming into a film, there is a possibility that the stretching will be broken. On the other hand, if it is too large, not only the fluidity at the time of molding tends to be lowered and the productivity or moldability tends to be lowered, but also there is a possibility that the deterioration is severe due to shearing heat generation during filtration or extrusion.

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 of the polycarbonate resin obtained by the method of the present invention at a shear rate of 91.2 sec ⁻¹ measured at 240 ° C. is preferably 500 Pa · s or more, more preferably 1000 Pa · s or more, and particularly preferably 1500 Pa. S or more, and the upper limit thereof is preferably 5000 Pa · s or less, and preferably 4000 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, shear heat generation in 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.

Although there is no restriction | limiting in the glass transition temperature of the polycarbonate resin obtained by the method of this invention, It is preferable that it is 50 degreeC or more, More preferably, it is 110 degreeC or more, More preferably, it is 120 degreeC or more, Especially preferably, it is 130 degreeC or more. . If the glass transition temperature is too low, the heat resistance is inferior, and therefore the reliability of the optical member may be inferior.

On the other hand, if the glass transition temperature is high, the polycarbonate resin may deteriorate due to shear heat generation during extrusion, or the melt viscosity when filtering with a filter becomes too high, which may cause deterioration of the polycarbonate resin. The temperature is preferably less than 180 ° C, more preferably 150 ° C or less, further preferably 145 ° C or less, and particularly preferably 140 ° C or less.

The glass transition temperature can be measured with a differential scanning calorimeter (DSC), and the temperature at which the change in heat capacity appears at the lowest temperature (Tig) when measured at a heating rate of 20 ° C./min using about 10 mg of a sample. ) Is defined as the glass transition temperature in the present invention.

In the transesterification performed in the present 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 (11), Alternatively, it is inevitable that aromatic monohydroxy compounds such as substituted phenols are by-produced and remain in the polycarbonate resin.

Aromatic monohydroxy compounds may cause gas generation during filtration or odor during molding. Therefore, using an extruder equipped with a vacuum vent, it is preferably less than 0.2% by weight, more preferably 0. It is preferable to make it less than 1% by weight, particularly less than 0.08% 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.

In addition, these aromatic monohydroxy compounds may naturally have a substituent depending on the raw material to be 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 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. Before performing various moldings, if necessary, the resin may be heat stabilizer, neutralizer, UV absorber, mold release agent, colorant, antistatic agent, lubricant, lubricant, plasticizer, compatibilizer or Additives such as flame retardants can also be mixed with a tumbler, super mixer, floater, V-type blender, nauter mixer, Banbury mixer or extruder. Moreover, after filtering on the said conditions, it can also shape | mold directly on a film, without making it a pellet.

According to the method of the present invention, a polycarbonate resin with less coloring and less foreign matter is obtained. Therefore, a foreign matter having a maximum length of 25 μm or more contained in a film having a thickness of 35 μm ± 5 μm obtained by extrusion molding from the resin is preferably used. It can be 1000 / m ² or less, more preferably 500 / m ² or less, and most preferably 200 / m ² or less. Such a characteristic with less foreign matters is particularly preferable when the polycarbonate resin is used for optical applications.

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

According to the present invention, it is possible to provide a polycarbonate resin pellet or a polycarbonate resin film that is excellent in thermal stability, hue, and mechanical strength and has few foreign substances. In the production of polycarbonate resin film, the polycarbonate resin pellets are manufactured not only by using the pellets after the above procedure, but also by molding into a film without going through the pellet state. May be.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples unless it exceeds the gist. In the following, the physical properties and characteristics of polycarbonate were evaluated by the following methods.

In the following, physical properties and characteristics of polycarbonate were evaluated by the following methods. *

(1) Measurement of oxygen concentration in polymerization reactor
An oxygen meter (manufactured by AMI: 1000RS) was used for measurement.

(2) Reduced viscosity A polycarbonate resin having a concentration of 0.6 g / dL was prepared by dissolving methylene chloride using a polycarbonate resin as a solvent. Using an Ubbelohde type viscosity tube (Moriyu Rika Kogyo Co., Ltd.), measurement is performed at a temperature of 20.0 ° C. ± 0.1 ° C., and the relative viscosity ηrel is obtained from the following equation from the solvent passage time t0 and the solution passage time t. ,
ηrel = t / t0
From the relative viscosity, the specific viscosity ηsp was determined from the following formula.
ηsp = (η−η0) / η0 = ηrel−1
The reduced viscosity ηsp / c was determined by dividing the specific viscosity by the concentration c (g / dL). The higher this value, the higher the molecular weight.

(3) Glass Transition Temperature of Polycarbonate Resin The glass transition temperature of the polycarbonate resin was measured using a differential scanning calorimeter (DSC 6220 manufactured by SII Nano Technology). About 10 mg of a polycarbonate resin sample was put in an aluminum pan manufactured by the same company and sealed, and the temperature was raised from room temperature to 250 ° C. at a temperature rising rate of 20 ° C./min under a nitrogen stream of 50 mL / min. After maintaining the temperature for 3 minutes, it was cooled to 30 ° C. at a rate of 20 ° C./min. The temperature was maintained at 30 ° C. for 3 minutes, and the temperature was increased again to 200 ° C. at a rate of 20 ° C./min. From the DSC data obtained at the second temperature increase, the extrapolated glass transition start temperature was adopted.

(4) Measurement of the structural unit ratio derived from each dihydroxy compound in the polycarbonate resin The structural unit ratio derived from each dihydroxy compound in the polycarbonate resin was obtained by weighing 30 mg of the polycarbonate resin and dissolving it in about 0.7 mL of deuterated chloroform. The solution was put into an NMR tube having an inner diameter of 5 mm, and a 1H NMR spectrum was measured at room temperature using JNM-AL400 (resonance frequency 400 MHz) manufactured by JEOL. The structural unit ratio derived from each dihydroxy compound was determined from the signal intensity ratio based on the structural unit derived from each dihydroxy compound.

(5) Measurement of phenol content and DPC content in polycarbonate resin Dissolve 1.00 g of a polycarbonate resin sample in 5 ml of methylene chloride to prepare a solution, and then add acetone to make the total amount 25 ml for reprecipitation treatment. Went. The solution was filtered through a 0.2 μm disk filter and quantified by liquid chromatography.

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

Measure using white calibration plate CM-A210, L * is 99.40 ± 0.05, a * is 0.03 ± 0.01, b * is −0.43 ± 0.01, YI is − It was confirmed to be 0.58 ± 0.01. The pellets were measured by putting the pellets to a depth of 30 mm or more in a cylindrical glass container having an inner diameter of 30 mm and a height of 50 mm. The operation of taking out the pellet from the glass container and then performing the measurement again was repeated twice, and the average value of the measurement values of three times in total was used. The smaller the YI value, the better the quality without yellowness.

(7) Melt viscosity Melt viscosity (Pa · s):
A sample dried at 120 ° C. for 6 hours was heated to 240 ° C. using a capillary rheometer (manufactured by Toyo Seiki Co., Ltd.) equipped with a die having a capillary having a diameter of 1 mmφ × length of 10 mmL, and a shear rate γ = 9 .12 ~ measured between 1824 ^{(sec -1),} it was read melt viscosity at 91.2sec ^-1.

(8) Birefringence wavelength dispersibility Polycarbonate resin vacuum-dried at 80 ° C. for 5 hours is converted into a single-screw extruder (made by Isuzu Chemical Industries, screw diameter 25 mm, cylinder set temperature: 220 ° C.), T-die (width 200 mm). A film having a thickness of 100 μm ± 5 μm was prepared using a film forming apparatus equipped with a chill roll (set temperature: 120 to 130 ° C.) and a winder.

A sample having a width of 6 cm and a length of 6 cm was cut out from the film. This sample was placed in a batch type biaxial stretching apparatus (manufactured by Toyo Seiki Co., Ltd.) with a glass transition temperature of the polycarbonate resin + 15 ° C. and a stretching speed of 720 mm / min (strain speed of 1200% / min). Uniaxial stretching of 0 times was performed to obtain a transparent film having a uniform thickness. At this time, it extended | stretched in the perpendicular | vertical direction with respect to the extending | stretching state in the hold | maintained state (drawing ratio 1.0).

A sample obtained by cutting the transparent film into a width of 4 cm and a length of 4 cm is measured for a phase difference (R450) at a measurement wavelength of 450 nm and a phase difference (R550) at 550 nm using a phase difference measuring device (KOBRA-WPR manufactured by Oji Scientific Instruments). did. And the ratio (R450 / R550) of the measured phase difference (R450) and phase difference (R550) was calculated. If the phase difference ratio is greater than 1, the chromatic dispersion is positive, and if it is less than 1, it is negative (reverse dispersion). It is shown that the smaller the ratio of the respective phase differences is less than 1, the stronger the negative wavelength dispersion.

(9) Evaluation method for the number of foreign substances: OPTICAL CONTROL SYSTEMS, Inc., single screw extruder (caliber 20 mm, single flight, L / D = 25), cast film die (150 mm width), chill roll, cylinder setting temperature 250 ° C. A film having a thickness of 35 ± 5 μm was formed at a roll temperature of 133 ° C., and foreign matters of 25 μm or more were counted using a gel counter system (form FSA100).
(10) Frequency of strands running out of gas Continuous operation was performed, and the frequency of strands running out of gas was counted.

The abbreviations of the compounds used in the description of the following examples are as follows.
BHEPF: 9,9-bis (4- (2-hydroxyethoxy) -phenyl) fluorene (Osaka Gas Chemical Co., Ltd.)
BCF: 9,9-bis (4-hydroxy-3-methylphenyl) fluorene (manufactured by Osaka Gas Chemical Co., Ltd.)
ISB: Isosorbide (Rocket Fleure, trade name: POLYSORB PS)
・ PEG: Polyethylene glycol (manufactured by Sanyo Chemical Industries)
・ DEG: Diethylene glycol (Mitsubishi Chemical Corporation)
・ CHDM: 1,4-cyclohexanedimethanol (manufactured by Shin Nippon Rika Co., Ltd.)
・ 1,6-HD: 1,6-hexanediol (manufactured by BASF)
SPG: Spiroglycol (also known as 3,9-bis (1,1-dimethyl-2-methoxyethyl) -2,4,8,10-tetraoxaspiro [5.5] undecane) (Mitsubishi Gas Chemical Co., Ltd.) )
・ DPC: Diphenyl carbonate (Mitsubishi Chemical Corporation)

[Example 1]
In a raw material preparation tank sufficiently purged 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, while supplying a constant amount continuously, the 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 (converted to magnesium metal atom) per 1 mol of all dihydroxy compounds. Was continuously supplied.

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. A horizontal stirring reactor having two horizontal rotating shafts and discontinuous stirring blades mounted substantially at right angles to the horizontal shaft, continuously extracted from the tank bottom using a self-circulating sealed gear pump (4th polymerization reactor).

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 has an additive supply port and three vent ports, L / D = 42, the length of the kneading disk occupying the length of the element constituting the entire screw of the extruder (kneading element) A self-circulating seal type gear pump was continuously supplied to a twin screw extruder having a ratio of 6%. The pipe connecting the gear pump and the extruder is a jacket-type double pipe in which the heat medium flows to the outside, and the temperature of the heat medium is set to 250 ° C.

The temperature of the resin supplied to the extruder was 248 ° C. when measured with a resin thermometer installed at the inlet of the extruder. In the extruder, 0.1% of water was supplied to the polycarbonate resin to be treated, and the vent port was connected to a vacuum pump to remove volatile components contained in the polycarbonate resin.

The heater temperature of the barrel of the extruder was set to 245 ° C. for the upstream 4 blocks, 225 ° C. for the 6 blocks downstream, and the screw speed was 274 rpm. At this time, the polycarbonate resin supplied to the extruder was temporarily extracted and subjected to various analyses. The results are shown in Table 1.

In Table 1, the kneading element ratio is a value calculated from the following formula.
Kneading element ratio (%) = (total length of kneading disc / total length of screw) × 100

The polycarbonate resin processed by the extruder was supplied to a filter unit having a resin inlet at the bottom and an outlet at the top through a gear pump installed at the outlet. Table 1 shows the temperature of the resin sampled before the filter unit and various measured values.

Inside the filter unit, a leaf disk filter having a mesh size of 7 μm [manufactured by Nippon Pole Co., Ltd.] [material is stainless steel (SUS304, SUS316)] was installed to remove foreign substances in the polycarbonate resin. Prior to use, the filter was roasted at 310 ° C. for 40 hours in a water vapor atmosphere and then at 420 ° C. for 52 hours in an air atmosphere, cooled to room temperature, and then immersed in a 30% by weight nitric acid aqueous solution for 30 minutes. Then, an oxide film was formed, washed and dried.

The filter unit was equipped with a heater composed of a plurality of blocks, and each temperature was set to 245 ° C. On the outlet side of the filter unit, a die was installed through a polymer pipe equipped with a heater composed of a plurality of blocks. The set temperature of the heater of the polymer pipe was set to 240 ° C., and the heater of the dice was set to 235 ° C.

¡A sensor for measuring the resin temperature was installed in the outlet channel of the filter unit. The temperature of the polycarbonate resin discharged from the die was measured using a thermometer. The resin temperature at the die outlet was directly measured by inserting a thermometer into the die hole. The polycarbonate resin was extracted in the form of a strand in a room maintained at a class 10000 cleanness from the die, solidified in a water tank, and pelletized with a rotary cutter. The analytical values are shown in Table 1.

[Example 2]
The raw materials were prepared so that the molar ratio of BHEPF / ISB / PEG (average molecular weight 1000) / DPC was 40.3 / 59.4 / 0.3 / 99, and the internal temperature of the first polymerization reactor was 194 ° C. The pressure is 27.8 kPa, the internal temperature of the second polymerization reactor is 208 ° C., the pressure is 25.8 kPa, the internal temperature of the third polymerization reactor is 221 ° C., the pressure is 23.0 kPa, and the vicinity of the inlet of the fourth polymerization reactor The inner temperature of the outlet is 225 ° C., the inner temperature near the outlet is 239 ° C., the pressure is 1.3 kPa, the screw speed of the extruder, the polycarbonate resin extrusion rate / extruder barrel cross-sectional area, the filter heater set temperature, and the filter surface This was performed in the same manner as in Example 1 except that the molten resin linear velocity was changed as shown in Table 1. The analytical values are shown in Table 1.

[Example 3]
Set the heater temperature of the barrel of the extruder to 240 ° C for the upstream 4 blocks and 220 ° C for the 6 blocks downstream. Table 1 shows the screw rotation speed of the extruder, the heater setting temperature of the filter, and the heater setting temperature of the die. The procedure was the same as Example 2 except that the procedure was changed. The analytical values are shown in Table 1.

[Example 4]
The same procedure as in Example 1 was carried out except that a part of the polycarbonate resin was extracted from the piping for supplying the polycarbonate resin to the extruder from the fourth polymerization reactor, and the amount of the resin supplied to the extruder was reduced.

[Example 5]
The raw materials were prepared so that the molar ratio of BHEPF / ISB / DPC was 40/60/100, the pressure of the first polymerization reactor was 33 kPa, the internal temperature of the second polymerization reactor was 201 ° C., the pressure was 25 kPa, The internal temperature of the 3 polymerization reactor is 241 ° C., the pressure is 18.3 kPa, the internal temperature near the inlet of the fourth polymerization reactor is 235 ° C., the internal temperature near the outlet is 250 ° C., and the pressure is 1.1 kPa. Except that the amount of extrusion / cross-sectional area of the barrel of the extruder, the inner volume of the filter storage container / the flow rate of the polycarbonate resin, and the linear velocity of the molten resin on the filter surface were changed as shown in Table 1, the same procedure as in Example 1 was performed. The analytical values are shown in Table 1.

[Example 6]
A side feeder is installed downstream of the vent port, and pentaerythrityl tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] (trade name: IRGANOX1010) is added to 100 parts by weight of polycarbonate resin. In contrast to the above, 0.1 parts by weight of tris (2,4-di-t-butylphenyl) phosphite (trade name: ADK STAB 2112) was continuously supplied to the same amount of 0.05 parts by weight. Same as 2.

[Example 7]
The length of the kneading disk occupying the length of the elements constituting the entire screw of the extruder is 12%, a side feeder is installed downstream of the vent port, and pentaerythrityl tetrakis [3- (3,5-dioxy -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 (product) Name: ADK STAB 2112) was carried out in the same manner as in Example 1 except that 0.05 parts by weight was continuously supplied.

[Example 8]
In the fourth polymerization reactor, the internal temperature near the inlet is 220 ° C., the internal temperature near the outlet is 235 ° C., the pressure is 1.2 kPa, and the heat medium temperature of the pipe connecting the gear pump and the extruder at the fourth polymerization reactor outlet Is set to 230 ° C, the heater temperature of the barrel of the extruder is set to 240 ° C for the upstream 4 blocks, and 220 ° C for the 6 blocks downstream, and the screw speed of the extruder, the heater set temperature of the filter, The heater set temperature was changed as shown in Table 1.

A side feeder is installed downstream of the vent port, and pentaerythrityl tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] (trade name: IRGANOX1010) is added to 100 parts by weight of polycarbonate resin. In contrast, 0.1 parts by weight of tris (2,4-di-t-butylphenyl) phosphite (trade name: ADK STAB 2112) was continuously supplied to the same amount of 0.05 parts by weight. 1 was performed.

[Example 9]
As a raw material monomer, a raw material prepared so that the molar ratio of BHEPF / ISB / DEG / DPC was 37.0 / 52.7 / 10.3 / 101 was used, and magnesium acetate tetrahydrate was used as a catalyst. The dihydroxy compound was used in an amount of 14 × 10 ⁻⁶ mol per 1 mol of the dihydroxy compound (magnesium metal atom equivalent), and the feed rate per unit time of the raw material was increased from that in Example 8, and the residence time of the first polymerization reactor was 0.9. The residence time of the second polymerization reactor is 0.6 hours, the residence time of the third polymerization reactor is 0.6 hours, the residence time of the fourth polymerization reactor is 1.1 hours, Implementation was performed except that the pressure was 0.7 kPa, the filter opening was 15 μm, and tris (2,4-di-t-butylphenyl) phosphite (trade name: ADK STAB 2112) was not added. 8 and was carried out in the same manner.

[Example 10]
As a raw material monomer, a raw material prepared so that the molar ratio of BCF / SPG / CHDM / DPC was 29.3 / 35.9 / 34.8 / 103 was used, and calcium acetate monohydrate was used as a catalyst. The dihydroxy compound was used at 200 × 10 ⁻⁶ mol (calcium metal atom equivalent) per mol, and the heat medium temperature of the pipe connecting the gear pump at the outlet of the fourth polymerization reactor and the extruder was set to 240 ° C. The same procedure as in Example 1 was carried out except that no stabilizer was added.

[Example 11]
As a raw material monomer, a raw material prepared so that the molar ratio of BCF / SPG / 1,6-HD / DPC was 30.9 / 47.4 / 21.7 / 102 was used, and calcium acetate monohydration was used as a catalyst. The product was used in the same manner as in Example 10, except that the product was used in an amount of 250 × 10 ⁻⁶ mol (calculated as calcium metal atom) per mol of the total dihydroxy compound.

[Comparative Example 1]
Example 1 except that the kneading element ratio of the extruder was 12%, the screw rotation speed of the extruder was 285 rpm, the heater setting temperature of the filter, the heater setting temperature of the polymer pipe, and the die setting temperature were 280 ° C. It carried out like. Although the pressure difference at the inlet / outlet of the filter decreased and it became easier to filter, the obtained pellets and film were markedly colored and foreign matter increased.

Results are shown in Tables 1 and 2.

The entire contents of the specification, claims, drawings and abstract of Japanese Patent Application No. 2011-78639, as well as part or all of the contents disclosed in the patent documents cited in this specification, are cited here. However, it is incorporated as the disclosure content of the specification of the present invention.

1a Raw material (carbonic acid diester)

supply port

1b, 1c Raw material (dihydroxy compound) supply port 1d Catalyst supply port 2a Raw material mixing tank 3a Anchor type stirring blade 4a Raw material mixed

liquid transfer pump

4b, 4c, 4d Gear pump 5a Raw material filtration filter 6a First Vertical stirring reaction tank 6b Second vertical stirring reaction tank 6c Third vertical stirring reaction tank 6d Fourth horizontal stirring

reaction tank

7a, 7b, 7c Max blend blade 7d Biaxial

glasses stirring blade

8a, 8b

Internal heat exchanger

9a,

9b Reflux coolers

10a,

10b Reflux pipes

11a, 11b, 11c,

11d Distillate pipes

12a, 12b, 12c,

12d Condensers

13a, 13b, 13c, 13d Depressurizer 14a Distillate recovery tank 15a Extruder 15b Polymer Filter 15c Die 16a Strand cooling tank 16b Strand cutter 16c Air feed blower 16 Product hopper 16e meter 16f product bag (paper bag, such as a flexible container)

Claims

A polycarbonate resin obtained by polycondensation of a dihydroxy compound and a carbonic acid diester is filtered using a filter and then cooled and solidified.
The dihydroxy compound includes at least a dihydroxy compound represented by the following general formula (1),
The aperture of the filter is 50 μm or less,
A method for producing a polycarbonate resin, comprising filtering the polycarbonate resin so that the temperature of the polycarbonate resin after filtration using the filter is 200 ° C. or higher and lower than 280 ° C.

[In the general formula (1), R 1 to R 4 are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted carbon number 6 to 20 carbon atoms. Or a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, and X is a substituted or unsubstituted alkylene group having 2 to 10 carbon atoms, substituted or unsubstituted carbon number It represents a cycloalkylene group having 6 to 20 carbon atoms or a substituted or unsubstituted arylene group having 6 to 20 carbon atoms, and m and n are each independently an integer of 0 to 5. ]
The method for producing a polycarbonate resin according to claim 1, wherein the polycarbonate resin obtained by cooling and solidifying has a glass transition temperature of 50 ° C or higher and lower than 180 ° C.
The method for producing a polycarbonate resin according to claim 1 or 2, wherein the reduced viscosity (ηsp / c) of the polycarbonate resin obtained by cooling and solidifying is 0.2 dL / g or more and 0.6 dL / g or less.
4. The melt viscosity at a shear rate of 91.2 sec −1 measured at 240 ° C. of the polycarbonate resin obtained by cooling and solidifying is 1000 Pa · s or more and 5000 Pa · s or less. 5. A method for producing a polycarbonate resin as described in 1. above.
The polycarbonate resin obtained by cooling and solidifying is obtained by using 18 mol% or more of the dihydroxy compound represented by the general formula (1) as a raw material monomer with respect to the total dihydroxy compound. 5. The method for producing a polycarbonate resin according to any one of 4 above.
When the reduced viscosity (ηsp / c) of the polycarbonate resin before filtering through the filter is A, and the reduced viscosity (ηsp / c) of the polycarbonate resin obtained by cooling and solidification is B,
The manufacturing method of the polycarbonate resin of any one of Claims 1 thru | or 5 which satisfy | fills following formula (2).
0.8 <B / A <1.1 (2)
The polycarbonate resin is obtained by polycondensation of at least a dihydroxy compound represented by the general formula (1) and a carbonic acid diester by an ester exchange reaction in the presence of a catalyst. 2. A method for producing a polycarbonate resin according to item 1.
The method for producing a polycarbonate resin according to claim 7, wherein the polycarbonate resin obtained by the polycondensation is supplied to the filter in a molten state without being solidified and filtered.
The polycondensation is performed using a catalyst;
The method for producing a polycarbonate resin according to claim 7 or 8, 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 said polycarbonate resin uses the dihydroxy compound which has a site | part represented by following General formula (3) in a part of structure other than the dihydroxy compound represented by the said General formula (1) as a raw material monomer. The method for producing a polycarbonate resin according to any one of 9.

[However, the case where the moiety represented by the general formula (3) is a part of —CH 2 —O—H is excluded. ]
The dihydroxy compound having a site represented by the general formula (3) is a compound having a cyclic ether structure, and the site represented by the general formula (3) is a part of the cyclic ether structure. The manufacturing method of polycarbonate resin of description.
In addition to the dihydroxy compound represented by the general formula (1) as a raw material monomer, the polycarbonate resin is a dihydroxy compound represented by the following general formula (4), a dihydroxy compound represented by the following general formula (5), The production of a polycarbonate resin according to any one of claims 1 to 11, wherein at least one dihydroxy compound selected from the group consisting of a dihydroxy compound represented by the dihydroxy compound represented by the following general formula (6) is used. Method.

[In the general formula (4), R 5 represents a substituted or unsubstituted cycloalkylene group having 4 to 20 carbon atoms. ]

[In the general formula (5), R 6 represents a substituted or unsubstituted cycloalkylene group having 4 to 20 carbon atoms. ]

[In General Formula (6), R 11 represents a chain alkylene group having 2 to 20 carbon atoms. ]
The filter is stored in a container, and a value obtained by dividing the internal volume (m 3 ) of the storage container by the flow rate (m 3 / min) of the polycarbonate resin to be filtered is 2 to 10 minutes. 13. The method for producing a polycarbonate resin according to any one of 12 above.
The method for producing a polycarbonate resin according to any one of claims 1 to 13, wherein a linear velocity of the molten resin on the filter surface is 0.01 to 0.5 m / h.
The polycarbonate according to any one of claims 1 to 14, wherein the content of the aromatic monohydroxy compound contained in the polycarbonate resin obtained by cooling and solidifying is 0.0001 wt% or more and less than 0.2 wt%. Manufacturing method of resin.
The method for producing a polycarbonate resin according to any one of claims 1 to 15, wherein the raw material monomer is filtered through a raw material filter before the polycondensation reaction.
The method for producing a polycarbonate resin according to any one of claims 1 to 16, wherein the filter is made of a metal that has been previously baked at a temperature of 350 ° C or higher and 500 ° C or lower.
18. The production of a polycarbonate resin according to claim 1, wherein the polycarbonate resin before filtration is supplied from a lower part of the storage container of the filter, and the polycarbonate resin after filtration is discharged from an upper part of the storage container. Method.
The method for producing a polycarbonate resin according to any one of claims 1 to 18, wherein the polycarbonate resin is devolatilized by a twin screw extruder having a vent port, and then supplied to the filter and filtered.
The screw of the extruder is composed of a plurality of elements, at least one of the elements is a kneading disk, and the total length of the kneading disk is 20% or less of the total length of the screw. The manufacturing method of the polycarbonate resin of Claim 19.
The following formula (7) is satisfied when the weight of the resin extruded per hour by the extruder is W (kg / h) and the cross-sectional area of the barrel of the extruder is S (m 2 ): 20. A method for producing a polycarbonate resin according to 20.
12000 ≦ W / S ≦ 60000 (7)
The method for producing a polycarbonate resin according to any one of claims 19 to 21, wherein the temperature of the polycarbonate resin supplied to the extruder is 200 ° C or higher and lower than 250 ° C.
The method for producing a polycarbonate resin according to any one of claims 19 to 22, wherein the temperature of the polycarbonate resin supplied to the filter is 230 ° C or higher and lower than 280 ° C.
The reduced viscosity (ηsp / c) of the polycarbonate resin supplied to the extruder is a,
When the reduced viscosity (ηsp / c) of the polycarbonate resin obtained by cooling and solidifying is B,
The method for producing a polycarbonate resin according to any one of claims 19 to 23, wherein the following formula (8) is satisfied.
0.8 <B / a <1.1 (8)
The method for producing a polycarbonate resin according to any one of claims 19 to 24, wherein a gear pump is disposed between the extruder and the filter.
A polycarbonate resin having a yellow index value of 70 or less obtained by the production method according to any one of claims 1 to 25.
A polycarbonate resin obtained by the production method according to any one of claims 1 to 25 or a film having a thickness of 20 µm to 200 µm obtained by extrusion molding of the polycarbonate resin according to claim 26, A polycarbonate resin film having a maximum length of 25 μm or more contained in a film of 1000 / m 2 or less.
A polycarbonate resin obtained by using a dihydroxy compound having a structural unit represented by the following general formula (1) as a raw material monomer is filtered using a filter in a molten state, discharged from a die, cooled, and then polycarbonate A method for producing a resin pellet or a polycarbonate resin film,
The dihydroxy compound includes at least a dihydroxy compound having a site represented by the following general formula (1) in a part of the structure;
The aperture of the filter is 50 μm or less,
The method of producing a polycarbonate resin pellet or a polycarbonate resin film, wherein the temperature of the resin discharged from the die is 200 ° C. or higher and lower than 280 ° C.

[In the general formula (1), R 1 to R 4 are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted carbon number 6 to 20 carbon atoms. Or a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, and X is a substituted or unsubstituted alkylene group having 2 to 10 carbon atoms, substituted or unsubstituted carbon number It represents a cycloalkylene group having 6 to 20 carbon atoms or a substituted or unsubstituted arylene group having 6 to 20 carbon atoms, and m and n are each independently an integer of 0 to 5. ]