Method for producing polycarbonate resin and molded body

Abstract

The present invention addresses the problem of providing a new method for producing a polycarbonate resin having excellent properties.　This problem has been solved by providing a method for producing a polycarbonate resin containing a constituent unit derived from an aromatic dihydroxy compound represented by formula (1). The method has a polymerization step for polymerizing the aromatic dihydroxy compound represented by formula (1). In the polymerization step, a raw material substance is used in which the concentration of compounds represented by formula (2), which are impurities, is 80 ppm or less relative to the total weight of the aromatic dihydroxy compound represented by formula (1) and the compounds represented by formula (2). (In formula (1) and formula (2), R1 to R3, X, a, b, m and n are as described in the description of the present application.)

Description

[Technical field]

[0001] The present invention relates to a method for producing a polycarbonate resin. [Background technology]

[0002] 2. Description of the Related Art Conventionally, methods for producing polycarbonate resins have been known that include a step of polymerizing a raw material monomer, a bisphenol compound (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2003-286213 A DISCLOSURE OF THEINVENTION [Problem to be solved by the invention]

[0004] In some conventional methods for producing polycarbonate resins, the properties of the resulting polycarbonate resins are not always fully satisfactory. For example, the conventional methods may produce polycarbonate resins with poor properties such as hue and melt tension.

[0005] Therefore, there has been a need for the development of a new production method that can reliably produce polycarbonate resin having excellent properties. [Means for solving the problem]

[0006] The present invention provides the following method for producing a polycarbonate resin, etc. (I) A method for producing a polycarbonate resin containing a structural unit derived from an aromatic dihydroxy compound represented by the following formula (1), The process includes a polymerization step of polymerizing an aromatic dihydroxy compound represented by the formula (1), In the polymerization step, a raw material having a concentration of an impurity compound represented by the following formula (2) of 80 ppm or less based on the total weight of the aromatic dihydroxy compound of the formula (1) and the compound of the formula (2) is used. [ka] (In formula (1), R1 and R2 each independently represent a hydrogen atom, a halogen atom, an optionally substituted or branched alkyl group having from 1 to 20 carbon atoms, or an optionally substituted aryl group having from 6 to 30 carbon atoms; R3 represents a hydrogen atom, an optionally substituted or branched alkyl group having from 1 to 20 carbon atoms, or an optionally substituted aryl group having from 6 to 30 carbon atoms; X represents an alkyl group having from 1 to 20 carbon atoms, an alkynyl group having from 1 to 20 carbon atoms, an alkenyl group having from 1 to 20 carbon atoms, or an aryl group having from 6 to 30 carbon atoms, which may be branched and may be substituted with a halogen atom; m and n each independently represent an integer of 0 to 2. [ka] (In formula (2), R1 and R2 each independently represent a hydrogen atom, a halogen atom, an optionally substituted or branched alkyl group having from 1 to 20 carbon atoms, or an optionally substituted aryl group having from 6 to 30 carbon atoms; R3 represents a hydrogen atom, an optionally substituted or branched alkyl group having from 1 to 20 carbon atoms, or an optionally substituted aryl group having from 6 to 30 carbon atoms; X represents an alkyl group having from 1 to 20 carbon atoms, an alkynyl group having from 1 to 20 carbon atoms, an alkenyl group having from 1 to 20 carbon atoms, or an aryl group having from 6 to 30 carbon atoms, which may be branched and may be substituted with a halogen atom; a and b each independently represent an integer of 0 to 3, provided that neither a nor b is 0; m and n each independently represent an integer of 0 to 2; However, the value of (a+m) is an integer of 4 or less, and the value of (b+n) is an integer of 4 or less.) (II) The method according to the above (I), wherein the aromatic dihydroxy compound represented by the formula (1) is represented by the following formula (1-a): [ka] (In formula (1-a), R1, R2, and X are the same as those in formula (1). (III) The method according to the above (I), wherein the compound represented by formula (2) is represented by the following formula (2-a): [ka] (In formula (2-a), R1, R2, a, b, and X are the same as those in formula (2). (IV) In the formulas (1) and (2), R1 and R2 are hydrogen, and X is a methyl group; The production method according to the above (I), wherein a is 1 and b is 0 in the formula (2). (V) The method according to the above (I), wherein R3 in the formula (1) and the formula (2) is a phenyl group. (VI) The process according to any one of the above (I) to (V), wherein the polycarbonate resin has an intrinsic viscosity of 0.2 dl / g or more and 1.0 dl / g or less. (VII) In a 7% by mass dichloromethane solution of the polycarbonate resin, * The method according to any one of the above (I) to (VI), wherein the value is 2.3 or less. (VIII) The production method according to any one of (I) to (VII) above, further comprising a concentration calculation step of calculating the concentration of the aromatic dihydroxy compound of formula (1) and the concentration of the compound of formula (2) before the polymerization step. (IX) The method according to any one of the above (I) to (VIII), further comprising an impurity removing step of removing at least a part of the compound of formula (2) from the raw material. (X) The production method according to any one of the above (I) to (IX), wherein in the polymerization step, the aromatic dihydroxy compound of the formula (1) is polymerized by an interfacial polycondensation method. (XI) A molded article comprising a polycarbonate resin obtained by the production method according to any one of (I) to (X) above. (XII) The molded article according to (XI) above, which is a film. Effect of the Invention

[0007] The method for producing a polycarbonate resin of the present invention produces a polycarbonate resin with excellent properties. That is, the production method of the present invention, which has a polymerization step of polymerizing an aromatic dihydroxy compound having a low concentration of a specific type of impurity, can reliably produce a polycarbonate resin with excellent properties such as hue. [Brief description of the drawings]

[0008] [Figure 1] 1 is a graph showing the relationship between the concentration of a specific impurity in the raw material of each Example and Comparative Example and the b* value of the produced polycarbonate resin. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] The present invention will be described in detail below. Note that the present invention is not limited to the following embodiments, and can be modified and carried out as desired within the scope of the effects of the invention.

[0010] [1. Manufacturing method of polycarbonate resin] The method for producing a polycarbonate resin of the present invention includes a polymerization step of polymerizing an aromatic dihydroxy compound of the above-mentioned formula (1), and the produced polycarbonate resin contains structural units derived from the aromatic dihydroxy compound of the formula (1). In the polymerization step, raw materials having a reduced content of impurities are used, i.e., the raw materials have a concentration of the compound represented by the above formula (2) of 80 ppm or less based on the total weight of the aromatic dihydroxy compound and the compound represented by formula (2). The raw materials, each step, and the polycarbonate resin produced in the production method of the present invention will be described below.

[0011] 1-1. Raw materials (a) Raw material monomer In the production of polycarbonate resin, raw materials are used to form structural units of the polymer chain of the polycarbonate resin. The raw materials contain an aromatic dihydroxy compound of the following formula (1) as a raw material monomer, and the aromatic dihydroxy compound of the following formula (1) is preferably the main component of the raw materials. [ka] In formula (1), R1 and R2 each independently represent a hydrogen atom, a halogen atom, an optionally substituted or branched alkyl group having 1 to 20 carbon atoms, or an optionally substituted aryl group having 6 to 30 carbon atoms. R1 and R2 are Preferably, it is a hydrogen atom, an optionally substituted or branched alkyl group having 1 to 10 carbon atoms, or an optionally substituted aryl group having 6 to 16 carbon atoms. More preferably, it is a hydrogen atom, an optionally substituted or branched alkyl group having from 1 to 6 carbon atoms, or an optionally substituted aryl group having from 6 to 12 carbon atoms. Particularly preferred are a hydrogen atom, an optionally substituted or branched alkyl group having 1 to 3 carbon atoms, or an optionally substituted aryl group having 6 to 8 carbon atoms. Preferable specific examples of R1 and R2 include a hydrogen atom, a methyl group, an isopropyl group, a phenyl group, and a hydroxyphenyl group, and among these, a hydrogen atom is preferable. In addition, examples of the substituents of R1 and R2 as an alkyl group or an aryl group include a halogen atom, a hydroxyl group, etc. The above-mentioned number of carbon atoms is the total number of carbon atoms including the number of carbon atoms of the substituent.

[0012] In formula (1), R3 represents a hydrogen atom, an optionally substituted or branched alkyl group having 1 to 20 carbon atoms, or an optionally substituted aryl group having 6 to 30 carbon atoms. R3 is, Preferably, it is a hydrogen atom, an optionally substituted or branched alkyl group having 1 to 10 carbon atoms, or an optionally substituted aryl group having 6 to 16 carbon atoms. More preferably, it is a hydrogen atom, an optionally substituted or branched alkyl group having from 1 to 6 carbon atoms, or an optionally substituted aryl group having from 6 to 12 carbon atoms. Particularly preferred are a hydrogen atom, an optionally substituted or branched alkyl group having 1 to 3 carbon atoms, or an optionally substituted aryl group having 6 to 8 carbon atoms. Preferable specific examples of R3 include a hydrogen atom, a methyl group, and a phenyl group, with the phenyl group being particularly preferable. The substituent of R3 as an alkyl group or an aryl group may be a halogen atom, a hydroxyl group, etc. The above carbon number is the total carbon number including the number of carbon atoms of the substituent.

[0013] In formula (1), X represents an alkyl group having 1 to 20 carbon atoms, an alkynyl group having 1 to 20 carbon atoms, an alkenyl group having 1 to 20 carbon atoms, or an aryl group having 6 to 30 carbon atoms, which may be substituted with a halogen atom and may be branched. X is Preferably, it is an optionally substituted or branched alkyl group having 1 to 10 carbon atoms, or an optionally substituted aryl group having 6 to 16 carbon atoms. More preferably, it is an optionally substituted or branched alkyl group having from 1 to 6 carbon atoms, or an optionally substituted aryl group having from 6 to 12 carbon atoms. Particularly preferred is an optionally substituted or branched alkyl group having 1 to 3 carbon atoms, or an optionally substituted aryl group having 6 to 8 carbon atoms. Preferred specific examples of X include a methyl group and a phenyl group, and among these, a methyl group is preferred. The substituent of X as an alkyl group or an aryl group may be a halogen atom, a hydroxyl group, etc. The above-mentioned number of carbon atoms is the total number of carbon atoms including the number of carbon atoms of the substituent.

[0014] In formula (1), m and n each independently represent an integer of 0 to 2. Preferably, m and n each independently represent 0 or 1, and more preferably 1.

[0015] A preferred example of the aromatic dihydroxy compound of formula (1) is one represented by the following formula (1-a). [ka] In formula (1-a), R1, R2, and X are the same as those in formula (1) above.

[0016] Specific examples of aromatic dihydroxy compounds contained as raw material monomers in raw materials include 1-phenyl-1,1-bis(4-hydroxyphenyl)ethane [=bisphenol AP], 2,2-bis(4-hydroxyphenyl)propane [=bisphenol A], bis(4-hydroxyphenyl)-p-diisopropylbenzene, 4,4'-dihydroxydiphenyl, 2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane, 2,2-bis(4-hydroxy-3-methylphenyl)propane, and propane, 2,2-bis(4-hydroxy-3,5-diethylphenyl)propane, 2,2-bis(4-hydroxy-3-ethylphenyl)propane, 2,2-bis(4-hydroxy-3,5-diphenylphenyl)propane, 2,2-bis(4-hydroxy-3-phenylphenyl)propane, 2,2-bis(4-hydroxy-3,5-dibromophenyl)propane, 2,2-bis(4-hydroxy-3-bromophenyl)propane, 2,2-bis(4-hydroxyphenyl)pentane, 2,4' -Dihydroxy-diphenylmethane, bis-(4-hydroxy-3-methylphenyl)methane, bis-(4-hydroxy-3-nitrophenyl)methane, 1,1-bis(4-hydroxyphenyl)ethane, 1,1-bis(4-hydroxy-3-methylphenyl)ethane, 3,3-bis(4-hydroxyphenyl)pentane, 1,1-bis(4-hydroxyphenyl)cyclohexane [=bisphenol Z], bis(4-hydroxyphenyl)sulfone, 2,4' -dihydroxydiphenylsulfone, bis(4-hydroxyphenyl)sulfide, 4,4' -dihydroxydiphenyl ether, 4,4' -dihydroxy-3,3' -dimethyldiphenyl ether, 4,4' -Dihydroxy-2,5-diethoxydiphenyl ether, 1,1-bis(4-hydroxy-3-methylphenyl)cyclohexane, 1-phenyl-1,1-bis(4-hydroxy-3-methylphenyl)ethane, bis(4-hydroxyphenyl)diphenylmethane, bis(4-hydroxy-3-methylphenyl)diphenylmethane, 9,9-bis(4-hydroxyphenyl)fluorene, 9,9-bis(4-hydroxy-3-methylphenyl)fluorene, 2,Examples of the aromatic dihydroxy compound include 2-bis(4-hydroxyphenyl)hexafluoropropane, but bis(4-hydroxyphenyl)alkanes are preferred, and 1-phenyl-1,1-bis(4-hydroxyphenyl)ethane [=bisphenol AP] is particularly preferred. These aromatic dihydroxy compounds can be used alone or in combination of two or more. The polycarbonate resin may be a homopolymer or a copolymer.

[0017] In addition to the aromatic dihydroxy compound, the raw material may contain a branching agent, such as 1,1,1-tris(4-hydroxyphenyl)ethane, as a raw material monomer for introducing a structural unit contained in the polymer chain of the polycarbonate resin. However, the raw material preferably contains 95% by mass or more of the aromatic dihydroxy compound based on the total weight of the raw material, more preferably 98% by mass or more of the aromatic dihydroxy compound, and particularly preferably 99% by mass or more of the aromatic dihydroxy compound. The branching agent is contained in the raw material in an amount of, for example, less than 5% by mass, preferably less than 2% by mass, more preferably less than 1% by mass based on the total weight of the raw material.

[0018] (b) Impurities in raw materials It is preferable that the source material has a low impurity content. In this specification, the term "impurities" refers to components other than the raw material monomers that form the structural units of the polycarbonate resin to be produced, and refers to trace components in the raw materials that do not fall under the category of those intentionally added for a specific purpose, such as additives. The compound represented by the following formula (2) tends to cause coloration in the polycarbonate resin obtained by polymerization of the raw material monomers, and deteriorates the hue, so that the content of this compound in the raw material material is preferably low. [ka]

[0019] R1 to R3 and X in formula (2) are each independently the same as R1 to R3 and X in formula (1), respectively. In formula (2), a and b each independently represent an integer of 0 to 3, provided that neither a nor b is 0. In formula (2), a and b each independently represent preferably 1 to 3, more preferably 2 or 3. In this way, in the impurity of formula (2) having many phenolic hydroxyl groups, a part of the phenolic hydroxyl groups remains unreacted in the polymerization step, and the ketonization of such free hydroxyl groups is considered to be the cause of coloring or the formation of unintended branched chains. Therefore, it is preferable to keep the content of impurities of formula (2) having many phenolic hydroxyl groups, such as triol bodies and those having a number of phenolic hydroxyl groups or more, in the raw material monomer, particularly low. However, the aromatic dihydroxy compound of formula (1) is prone to being contaminated with a compound of formula (2) in which either a or b is 1 and the other is 0 as an impurity. For this reason, it is important to reliably remove the compound of formula (2) in which a is 1 and b is 0, or the compound of formula (2) in which a is 0 and b is 1. In formula (2), m and n each independently represent an integer of 0 to 2, and are preferably each independently 0 or 1, and more preferably 1. However, in formula (2), the value of (a+m) is an integer of 4 or less, and the value of (b+n) is an integer of 4 or less. Furthermore, in formula (2), the value of (a+m) and the value of (b+n) are each independently preferably 3 or less, and more preferably 2 or less.

[0020] Thus, an example of the compound represented by formula (2) as an impurity (hereinafter also referred to as a specific impurity) is one represented by the following formula (2-a). [ka] In formula (2-a), R1, R2, a, b, and X are the same as those in formula (2).

[0021] The concentration of the specific impurity contained in the raw materials used in the polymerization step is 80 ppm by mass or less based on the total weight of the aromatic dihydroxy compound of formula (1) and the specific impurity, i.e., the compound of formula (2). More preferably, the concentration of the specific impurity based on the total weight of the aromatic dihydroxy compound of formula (1) and the specific impurity is 75 mass ppm or less, more preferably 72 mass ppm or less, and even more preferably 70 mass ppm or less. In addition, the concentration of the specific impurity may be, for example, 60 mass ppm or less, or 50 mass ppm or less. In addition, when the raw material contains raw material monomers such as dihydroxy compounds other than the aromatic dihydroxy compound of formula (1), the concentration of the specific impurities is preferably 80 ppm or less, more preferably 75 ppm or less, even more preferably 72 ppm or less, and particularly preferably 70 ppm or less, based on the total weight of the raw material. In addition, the concentration of the specific impurities may be, for example, 60 ppm or less, or 50 ppm or less.

[0022] As mentioned above, the specific impurities may cause coloration in the polycarbonate resin, so it is preferable to keep the concentration of the specific impurities in the raw material low. Therefore, although it is not particularly important to set a lower limit for the concentration of the specific impurities in the raw material, if a polycarbonate resin is produced using a raw material that does not contain any specific impurities, the melt tension may decrease when the resin is molded into a film. From these viewpoints, the lower limit for the concentration of the specific impurities in the raw material is, for example, 0.01 ppm by mass, 0.1 ppm by mass, or 1.0 ppm by mass.

[0023] The concentration of the specific impurity in the raw material is, for example, 0.01 to 70 ppm by mass, preferably 0.1 ppm to 50 ppm by mass, and more preferably 1 to 40 ppm by mass.

[0024] The raw material may contain impurities other than the specific impurities described above. Compounds of impurities other than the specific impurities include those represented by the following formulas (3) to (6). [ka] In formula (3), i is an integer of 0 to 5. The presence of a compound of the following formula (3-a) where i=0 or a compound of the following formula (3-b) where i=1 was confirmed in the raw material of a comparative example, the details of which will be described later. [ka] [ka]

[0025] The concentration of the compound of formula (3) in the raw material is preferably 400 ppm by mass or less, more preferably 300 ppm by mass or less, even more preferably 250 ppm by mass or less, and particularly preferably 200 ppm by mass or less, for example, 150 ppm by mass or less, or 120 ppm by mass or less.

[0026] Compounds of formula (4) that may be included in the raw material are as follows: [ka] In formula (4), k is an integer of 0 to 5, and compounds in which k=0 and k=1 were confirmed to exist in the raw materials of the examples described in detail below.

[0027] The concentration of the compound of formula (4) in the raw material is preferably 500 ppm by mass or less, more preferably 400 ppm by mass or less, even more preferably 300 ppm by mass or less, and particularly preferably 250 ppm by mass or less, for example, 200 ppm by mass or less, or 180 ppm by mass or less.

[0028] Compounds of formula (5) that may be included in the raw material are as follows: [ka] In formula (5), j is an integer of 1 to 5, and the compound where j=2 was confirmed to exist in the raw materials of the examples described in detail below.

[0029] The concentration of the compound of formula (5) in the raw material is preferably 300 ppm by mass or less, more preferably 250 ppm by mass or less, even more preferably 200 ppm by mass or less, and particularly preferably 150 ppm by mass or less, for example, 120 ppm by mass or less, or even more preferably 100 ppm by mass or less.

[0030] The compound of formula (6) that may be contained in the raw material is a mixture of the following two compounds or either one of them alone. [ka] The presence of the compound of formula (6) was confirmed in the raw materials of the examples described in detail below.

[0031] The concentration of the compound of formula (6) in the raw material is preferably 30 ppm by mass or less, more preferably 25 ppm by mass or less, even more preferably 20 ppm by mass or less, and particularly preferably 15 ppm by mass or less, for example, 12 ppm by mass or less, or even more preferably 10 ppm by mass or less.

[0032] As with the specific impurities, it is preferable to keep the concentration of impurities other than the specific impurities low in the raw material. Therefore, the total impurity concentration in the raw material, i.e., the total concentration of the specific impurities and other impurities in the raw material, is preferably 2.0 mass% or less, more preferably 1.5 mass% or less, and even more preferably 1.0 mass% or less, based on the total weight of the raw material, and particularly preferably 0.8 mass% (or 8,000 mass ppm) or less, for example, 0.6 mass% (or 6,000 mass ppm) or less, or 0.5 mass% (or 5,000 mass ppm) or less. Therefore, the purity of the raw material, i.e., the ratio of the weight of the raw material excluding the total amount of impurities (the total amount of specific impurities and other impurities) to the total weight of the raw material, is preferably higher than 98.0 mass%, more preferably higher than 98.5 mass%, even more preferably higher than 99.0 mass%, and particularly preferably greater than 99.2 mass%, for example, greater than 99.4 mass%, or greater than 99.5 mass%. Furthermore, although it cannot be said that the setting of the lower limit of the total impurity concentration is particularly important, the lower limit of the total impurity concentration is, for example, 0.01 ppm by mass, 0.1 ppm by mass, or 1.0 ppm by mass. As for impurities other than the specific impurities, it is preferable to keep the content of compounds having many phenolic hydroxyl groups, such as triols and compounds having a greater number of phenolic hydroxyl groups, low in the raw material monomers.

[0033] (c) Ingredients other than raw materials When polycarbonate resins are produced by the interfacial polycondensation method, a carbonate binder, a terminal terminator, a phase transfer catalyst, etc. are also used as components other than the raw materials.

[0034] Carbonate binders are used to bond the structural units derived from the raw material monomers, forming carbonyl groups (-C(=O)-) in the polymer chain of the polycarbonate resin. Carbonyl compounds such as phosgene, triphosgene, carbonic acid diesters, carbon monoxide, and carbon dioxide are used as carbonate binders. Examples of the carbonic acid diester include dialkyl carbonate compounds such as dimethyl carbonate, diethyl carbonate, and di-tert-butyl carbonate, diphenyl carbonate, and substituted diphenyl carbonates such as di-p-tolyl carbonate, phenyl-p-tolyl carbonate, and di-p-chlorophenyl carbonate. Among these, diphenyl carbonate and substituted diphenyl carbonates are preferred, and diphenyl carbonate is particularly preferred. These carbonic acid diester compounds can be used alone or in combination of two or more.

[0035] In the production of polycarbonate resins, the carbonate binder may be used in an excess amount relative to the raw materials (raw monomers), and the molar ratio of the raw materials to the carbonate binder is preferably in the range of 1:1.1 to 1:5, more preferably 1:1.2 to 1:3, and even more preferably 1:1.3 to 1:2, for example 1:1.4.

[0036] The terminal terminator is used to terminate the polymerization reaction of the raw material monomers and forms an end group of the polymer chain of the polycarbonate resin. As the terminal terminator, a monohydric phenol is preferably used. Examples of the end terminator include alkylphenols such as phenol, p-cresol, o-cresol, 2,4-xylenol, pt-butylphenol, o-allylphenol, p-allylphenol, p-hydroxystyrene, p-hydroxy-α-methylstyrene, p-propylphenol, p-cumylphenol, p-phenylphenol, o-phenylphenol, p-trifluoromethylphenol, p-nonylphenol, p-dodecylphenol, eugenol, amylphenol, hexylphenol, heptylphenol, octylphenol, nonylphenol, decylphenol, dodecylphenol, myristylphenol, palmitylphenol, stearylphenol, and behenylphenol, and alkyl esters of parahydroxybenzoic acid such as methyl ester, ethyl ester, propyl ester, butyl ester, amyl ester, hexyl ester, and heptyl ester. It is also possible to use two or more of the above monohydric phenols in combination.

[0037] The amount of the terminal terminator used is appropriately determined depending on the target molecular weight of the polycarbonate resin, etc., but the molar ratio of the amount of the raw material to the terminal terminator used is preferably in the range of 100:1 to 10:1, more preferably 50:1 to 15:1, still more preferably 40:1 to 20:1, for example, 25:1.

[0038] In addition, in the polymerization step of the interfacial polycondensation method, it is preferable to use a phase transfer catalyst. The phase transfer catalyst is mixed with the raw material monomer and the carbonate binder to produce a solution, for example, an aqueous solution, which is used in the polymerization reaction. A specific example of the phase transfer catalyst is a nitrogen-containing compound represented by the following general formula (7). [ka] In the general formula (7), n is any one of 2, 3 and 4. Y is an ethyl group, a propyl group, a butyl group, or a benzyl group. X is Cl, Br, OH, or HSO4.

[0039] Specific examples of such nitrogen-containing compounds include triethylbenzylammonium chloride (TEBAC), tributylbenzylammonium chloride (TBBAC), and the like, with triethylbenzylammonium chloride (TEBAC) being preferred.

[0040] The amount of phase transfer catalyst such as the nitrogen-containing compound represented by the general formula (7) is preferably small. Specifically, the amount of phase transfer catalyst is preferably less than 0.10% by mass, more preferably less than 0.05% by mass, and particularly preferably less than 0.02% by mass, based on the total weight of the raw material (raw material monomer) and the phase transfer catalyst. By using an appropriate amount of phase transfer catalyst, it is possible to prevent the formation of oligomers in the polycarbonate resin finally obtained, and it is possible to stably produce the desired polycarbonate resin. If an excessive amount of phase transfer catalyst exists in the reaction system of the polymerization reaction, it is considered to play the same role as a terminal terminator and promote the generation of oligomers.

[0041] In order to ensure the progress of the polymerization reaction, the lower limit of the amount of phase transfer catalyst used is preferably 0.001 mass% or more, more preferably 0.005 mass% or more, and particularly preferably 0.01 mass% or more, based on the total weight of the raw material (raw material monomer) and the phase transfer catalyst.

[0042] Polycarbonate resins can also be produced by the transesterification method, which uses, in addition to the raw materials, a carbonic acid diester, a basic compound catalyst, a transesterification catalyst, and other catalysts.

[0043] Examples of the carbonic acid diester include diphenyl carbonate, ditolyl carbonate, bis(chlorophenyl) carbonate, m-cresyl carbonate, dimethyl carbonate, diethyl carbonate, dibutyl carbonate, dicyclohexyl carbonate, etc. Among these, diphenyl carbonate is particularly preferred from the viewpoints of reactivity and purity. The carbonic acid diester is preferably used in a molar ratio of 0.60 to 1.30, more preferably 0.70 to 1.20, and particularly preferably 1.00 to 1.20, per mole of the raw material (raw material monomer). By adjusting this molar ratio, the molecular weight of the polyester carbonate resin can be controlled within a preferred range.

[0044] Examples of the basic compound catalyst include alkali metal compounds, alkaline earth metal compounds, and nitrogen-containing compounds. Examples of the alkali metal compound include organic acid salts, inorganic salts, oxides, hydroxides, hydrides, and alkoxides of alkali metals. From the viewpoints of catalytic effect, price, distribution volume, effect on the color of the resin, etc., sodium carbonate and sodium hydrogen carbonate are preferred. Examples of the alkaline earth metal compound include organic acid salts, inorganic salts, oxides, hydroxides, hydrides, and alkoxides of alkaline earth metal compounds. Examples of the nitrogen-containing compound include quaternary ammonium hydroxides and their salts, and amines.

[0045] As the transesterification catalyst, a salt of zinc, tin, zirconium or lead is preferably used, which may be used alone or in combination, or may be used in combination with the above-mentioned alkali metal compounds or alkaline earth metal compounds. Specific examples of the transesterification catalyst include zinc acetate, zinc benzoate, zinc 2-ethylhexanoate, tin(II) chloride, tin(IV) chloride, tin(II) acetate, tin(IV) acetate, dibutyltin dilaurate, dibutyltin oxide, dibutyltin dimethoxide, zirconium acetylacetonate, zirconium oxyacetate, zirconium tetrabutoxide, lead(II) acetate, lead(IV) acetate, zirconium acetate, and titanium tetrabutoxide. Among these, zinc acetate, zirconium acetate, and titanium tetrabutoxide are preferred, and titanium tetrabutoxide is more preferred.

[0046] The total amount of the basic compound catalyst and the transesterification catalyst used is 1×10 per mole of the raw material (raw monomer). -9 ~1×10 -3 In terms of molar ratio, preferably 1 x 10 -7 ~1×10 -4 Used in molar ratios.

[0047] 1-2. Polymerization process In the polymerization step, the raw material monomer, which is the main component of the raw material, is polymerized. Since the raw material contains the aromatic dihydroxy compound, at least the aromatic dihydroxy compound is polymerized in the polymerization step. In the polymerization step, as described above, in addition to the interfacial polycondensation method, it is also possible to employ an ester exchange method in which an aromatic dihydroxy compound is reacted with a carbonate diester in the presence of a catalyst.

[0048] The temperature of the polymerization reaction in the interfacial polycondensation method is preferably within the range of 5 to 60°C, more preferably 15 to 50°C, and even more preferably 20 to 40°C, for example, 30°C. In addition, the polymerization reaction in the interfacial polycondensation method is preferably carried out under normal pressure.

[0049] As a catalyst for the polymerization reaction in the interfacial polycondensation method, an alkylamine or the like is used, and as the alkylamine, for example, triethylamine is preferably used. As a catalyst for the polymerization reaction in the transesterification method, an alkali metal compound, an alkaline earth metal compound, or the like is used, and for example, sodium hydrogen carbonate, cesium carbonate, and sodium carbonate are preferably used.

[0050] The polymerization reaction in the transesterification method is preferably carried out under the following conditions. That is, the polymerization reaction in the transesterification method is carried out at a temperature of 120 to 350°C, preferably 180 to 260°C, for 0.1 to 5 hours, preferably 0.5 to 3 hours. Next, the reaction temperature is increased while increasing the degree of vacuum in the reaction system to react the diol compound with the carbonate diester, and finally, a polycondensation reaction is carried out at a temperature of 200 to 350°C under a reduced pressure of 1 mmHg or less for 0.05 to 2 hours. Such a reaction may be carried out continuously or batchwise. The reaction apparatus used in the polymerization reaction of the transesterification method may be a vertical type equipped with an anchor-type impeller, a Maxblend impeller, a helical ribbon-type impeller, etc., or a horizontal type equipped with a paddle impeller, a lattice impeller, a spectacle impeller, etc., or an extruder type equipped with a screw. It is preferable to use a reaction apparatus in which these are appropriately combined, taking into consideration the viscosity of the polycarbonate resin, which is the target product to be polymerized.

[0051] In the polymerization step, it is preferable to employ an interfacial polycondensation method (interfacial method, interfacial polymerization method). When a raw material monomer containing an aromatic dihydroxy compound represented by the above formula (1) is polymerized by the interfacial polycondensation method, the color of the resulting polycarbonate resin tends to be superior to that of a polycarbonate resin produced by other production methods, for example, a melting method.

[0052] 1-3. Concentration calculation process In the method for producing a polycarbonate resin, it is preferable to calculate the concentrations of raw materials and impurities before the polymerization step. That is, it is preferable to carry out a concentration calculation step of calculating the concentration of the aromatic dihydroxy compound in the raw materials, i.e., the purity of the raw materials and the concentration of the specific impurity, which is the compound of formula (2), before the polymerization step. The purity of the raw material and the concentration of specific impurities are calculated based on the masses of the raw material, raw monomer, and specific impurities measured according to known methods, and are preferably calculated as mass % or mass ppm based on the mass of the raw material.

[0053] In the concentration calculation step, it is preferable to calculate the concentration of at least the aromatic dihydroxy compound of formula (1) among the raw material monomers. It is also preferable to calculate the concentration of impurities other than the specific impurity contained in the raw material.

[0054] 1-4. Impurity removal process In the method for producing a polycarbonate resin, it is preferable to carry out an impurity removal step of removing at least a part of the specific impurity, which is a compound of formula (2), from the raw material before carrying out a polymerization reaction of the raw material monomer. In the impurity removal step, it is preferable to remove the specific impurity from the raw material based on crystallization of the raw material. In the impurity removal step, it is preferable to further wash the crystals obtained by crystallization of the raw material, and it is preferable to repeat the crystallization and washing steps. However, the impurity removal step may also include a step of lowering the concentration of the impurity by mixing a raw material having a lower concentration of the specific impurity with a certain raw material based on the result calculated by the above-mentioned concentration calculation step. In the impurity removing step, it is preferable to remove impurities other than the specific impurities.

[0055] According to the above-mentioned impurity removal step, it is possible to improve the purity of the raw material monomers in the raw material, and the color of the produced polycarbonate resin is improved. Although the polycarbonate resin produced by the polymerization reaction may be purified, if the above-mentioned impurities are incorporated into the polymer chain, such a purification step may not be effective in improving the hue sufficiently. In contrast, the impurities that may deteriorate the hue can be reliably removed by the impurity removal step that targets the raw material. Furthermore, in the impurity removing step, impurities can be efficiently removed by referring to the results of the purity and concentration of each component calculated in the concentration calculating step.

[0056] [2. Polycarbonate resin] The polycarbonate resin obtained by the above-mentioned production method will be described below.

[0057] 2-1.Structural units of polycarbonate resin A polycarbonate resin produced by a polymerization reaction of a raw material containing at least the aromatic dihydroxy compound of formula (1) contains a constitutional unit represented by the following formula (1-b) which is derived from the aromatic dihydroxy compound of formula (1). [ka] (In formula (1-b), R1 to R3, m, n, and X are the same as those in formula (1).

[0058] Furthermore, the polycarbonate resin obtained as a copolymer may contain structural units derived from multiple types of aromatic dihydroxy compounds represented by formula (1), or structural units other than the structural units derived from the aromatic dihydroxy compound of formula (1). The polycarbonate resin may be a random copolymer or a block copolymer.

[0059] 2-2. Properties of polycarbonate resin The polycarbonate resin preferably has an intrinsic viscosity of 0.2 dl / g or more and 1.0 dl / g or less, as measured by the method described below in accordance with JIS K-7367-1. The intrinsic viscosity of the polycarbonate resin is more preferably 0.3 dl / g or more and 0.7 dl / g or less, even more preferably 0.4 dl / g or more and 0.5 dl / g or less, and particularly preferably 0.41 dl / g or more and 0.49 dl / g or less.

[0060] For polycarbonate resin, JIS 7136-compliant b * Value, i.e., b of 5 cm solution of 7% by mass of polycarbonate resin in dichloromethane solution * It is preferable that the value of b is 2.3 or less. * The value is more preferably 2.0 or less, further preferably 1.8 or less, particularly preferably 1.6 or less, for example, 1.4 or less. According to the above-mentioned manufacturing method, b * This allows the production of polycarbonate resins with low oxidation resistance and excellent color tone.

[0061] The polycarbonate resin preferably has a viscosity average molecular weight (Mv) within the range of 10,000 to 60,000, more preferably the viscosity average molecular weight (Mv) value is 14,000 to 40,000, and further preferably 16,000 to 25,000.

[0062] The viscosity average molecular weight (Mv) of the above-mentioned polycarbonate resin is a value measured based on the following measurement conditions. <Viscosity average molecular weight (Mv) measurement conditions> Measuring instrument: Ubbelohde capillary viscometer Solvent: Dichloromethane Resin solution concentration: 0.5 grams / dl Measurement temperature: 25℃ Measure under the above conditions, determine the intrinsic viscosity [η] deciliters / gram with a Huggins constant of 0.45, and calculate using the following formula.

[0063]

number

[0064] The polycarbonate resin preferably has a glass transition point within the range of 100°C to 250°C. The glass transition point of the polycarbonate resin is more preferably 140°C to 200°C, and further preferably 160°C to 190°C.

[0065] The glass transition point of the above-mentioned polycarbonate resin is a value measured using a differential scanning calorimeter under the conditions shown below. <Conditions for measuring glass transition temperature> Measurement equipment: Shimadzu Corporation differential scanning calorimeter (DSC-50) Heating rate: 10℃ / min Gas flow environment: Nitrogen 20ml / min Sample pretreatment: Heat melting at 300℃

[0066] [3. Molded body] The molded article of the present invention contains the polycarbonate resin obtained by the above-mentioned production method.

[0067] Specific examples of the molded body include sheets and films, and other examples include thermoformed bodies. Specific examples of the thermoformed body include electric and electronic equipment, OA equipment, information terminal equipment, machine parts, home appliances, vehicle parts, building materials, various containers, leisure goods and sundries, parts of lighting equipment, etc., parts of various household electrical appliances, housings, containers, covers, storage parts, cases, covers and cases of lighting equipment, etc. Examples of the electric and electronic equipment include personal computers, game machines, television receivers, display devices such as liquid crystal displays and plasma display devices, printers, copy machines, scanners, fax machines, electronic organizers and PDAs, electronic desk calculators, electronic dictionaries, cameras, video cameras, mobile phones, smartphones, tablets, battery packs, drives and reading devices for recording media, mice, numeric keypads, CD players, MD players, portable radios and audio players, etc.

[0068] Further examples of the molded article include electric signboards, liquid crystal backlights, lighting displays, traffic signs, signboards, screens, reflectors, meter parts and other automobile parts, toys, ornaments, and the like. EXAMPLES

[0069] The present invention will be described in more detail below with reference to examples, but the present invention should not be construed as being limited to the following examples.

[0070] First, a method for measuring impurities contained in raw materials (raw material monomers) used in the production of polycarbonate resin will be described. <Method for measuring impurities in raw monomer> (1) Creating a calibration curve As a pure raw material monomer, bisphenol AP manufactured by Honshu Chemical Co., Ltd. was used. 200 mg of bisphenol AP was weighed into a 10 mL measuring flask and the solution was adjusted to a constant volume with methanol (20 mg / mL methanol solution). This solution was used as a stock solution and diluted with methanol to prepare calibration curve samples (0.50, 1.0, 2.5, 5.0 μg / mL). These solutions were analyzed by the measurement described below to create a calibration curve.

[0071] (2) Preparation of the measurement solution 200 mg of the raw material monomer was weighed out into a 10 mL measuring flask and diluted with methanol to a constant volume (20 mg / mL methanol solution), and this solution was analyzed by the measurement described below. (3) Measurement The measurement was performed by LC-Tof-MS (ESI-). The device and measurement conditions are described below. Equipment: Waters H-class Column: Waters ACQUITY UPLC BEH C18 (inner diameter 2.1 mm, length 100 mm, particle size 1.7 μm) Eluent: H2O / MeCN=50 / 50(0→5min), 50 / 50→5 / 95(5→10min), 5 / 95(10→15min) Flow rate: 0.3mL / min PDA: 210~500nm Column temperature: 40℃ Source temperature: 120℃ Desolvation temperature: 450℃ Capillary voltage: 3kV Sampling Cone Voltage: 40V Source Offset: 80 Cone Gas Flow: 50L / h Desolvation Gas Flow: 500L / h Injection volume: 0.5 μL (TIC), 1 μL (PDA chromatogram) Ionization method: ESI- Measurement mode: resolution Mass scan range: m / z 50~1000 Scan time: 0.5 seconds LockMass :m / z554.2615(Leucine Enkephalin) The concentration of each impurity in the examples and comparative examples described below was calculated in terms of bisphenol AP from the calibration curve obtained by the above-mentioned method.

[0072] Next, a method for measuring parameters indicating the properties of a polycarbonate resin will be described. <Intrinsic viscosity> The intrinsic viscosity was measured according to JIS K-7367-1. That is, the polycarbonate resin was dissolved in dichloromethane at a concentration of 5.0 g / L, and the intrinsic viscosity was determined using an Ubbelohde viscometer at 25° C. with a Huggins constant of 0.45.

[0073] * Value measurement> The measurement was performed in accordance with JIS K7136. That is, polycarbonate resin was dissolved in dichloromethane at a concentration of 70 g / L, the obtained polycarbonate resin solution was placed in a container with a width of 5 cm, and the transmittance was measured using a color difference meter SD6000 manufactured by Nippon Denshoku Co., Ltd. * The value was calculated.

[0074] Next, the manufacturing method of the bisphenol AP sample used as the raw material monomer for polycarbonate resin will be described. The bisphenol AP samples used were one synthesized from phenol and acetophenone, and a commercially available bisphenol AP. ​Bisphenol AP was synthesized by the method described in Patent 4168646 (JP Patent Publication 2003-286213). That is, acetophenone, phenol, and butyl mercaptan as a catalyst were charged into an autoclave equipped with a thermometer and a stirrer, and the mixture was heated with slow stirring and maintained at 50 to 60°C. Thereafter, the stirring speed was increased, hydrogen chloride gas was introduced, and the reaction was carried out for 6 hours at an internal pressure of 0.05 MPa to 0.10 MPa. The solvent was removed from the reaction liquid to obtain a bisphenol AP sample.

[0075] [Example 1] (Process 1) 100 g of bisphenol AP (BPAP) containing 36 ppm of a specific impurity having the molecular structure of formula (2-a) and 0.5 g of hydrosulfite were added and dissolved in 600 ml of 9 w / w% aqueous sodium hydroxide solution. 360 ml of dichloromethane was added to this solution, and while stirring, the solution temperature was set to 20°C, and 47.9 g of phosgene was further blown in over 30 minutes. (Process 2) After the phosgene injection was completed, 2 g of p-tert-butylphenol (PTBP) dissolved in 50 ml of dichloromethane was added and emulsified by vigorous stirring for 7 minutes, after which 0.5 ml of triethylamine was added as a polymerization catalyst and polymerization was carried out for about 30 minutes. (post-process) The polymerization solution was separated into an aqueous layer and an organic layer, and the organic layer was neutralized with phosphoric acid and repeatedly washed with pure water until the pH of the washing liquid reached pH 7.0. The organic solvent was evaporated from this purified polycarbonate resin to obtain a polycarbonate resin powder. The polycarbonate resin powder was dried at 120°C for 24 hours to completely evaporate the solvent. (Analysis results) The intrinsic viscosity of the obtained polycarbonate resin was 0.431 dl / g. * The viscosity average molecular weight (Mv) was 20,600 and the glass transition temperature was 182°C.

[0076] [Example 2] A polycarbonate resin was synthesized in the same manner as in Example 1, except that the amount of PTBP was 2.21 g. (Analysis results) The intrinsic viscosity of the obtained polycarbonate resin was 0.405 dl / g. * The viscosity average molecular weight (Mv) was 19,200 and the glass transition temperature was 181°C.

[0077] [Example 3, Comparative Example] Using bisphenol AP containing the specific impurity having the molecular structure of formula (2-a) in the amounts shown in Table 1, synthesis and analysis of polycarbonate resin were carried out in the same manner as in Example 1. The results are shown in Table 1. It was confirmed that the specific impurity in bisphenol AP used in Examples 1 to 3 and the Comparative Example had a molecular structure represented by the following formula (2-a), in which one of a and b is 1 and the other is 0, R1 and R2 are hydrogen, and X is a methyl group. [ka] The polycarbonate resin obtained in Example 3 had a viscosity average molecular weight (Mv) of 20,000 and a glass transition point of 184° C. The polycarbonate resin obtained in Comparative Example had a viscosity average molecular weight (Mv) of 19,200 and a glass transition point of 178° C. [Table 1]

[0078] As shown by the results of the above Examples and Comparative Examples, the production method of the present invention can provide polycarbonate resins excellent in properties such as hue.

Claims

1. A method for producing a polycarbonate resin containing a structural unit derived from an aromatic dihydroxy compound represented by the following formula (1-a), The process includes a polymerization step of polymerizing an aromatic dihydroxy compound represented by the formula (1-a), In the polymerization step, a raw material having a concentration of a compound represented by the following formula (2-a) as an impurity of 80 ppm or less based on the total weight of the aromatic dihydroxy compound of the formula (1-a) and the compound of the formula (2-a) is used. 【Chemistry 1】 (In formula (1-a), R １ and R ２ each independently represents a hydrogen atom, a halogen atom, an optionally substituted or branched alkyl group having from 1 to 20 carbon atoms, or an optionally substituted aryl group having from 6 to 30 carbon atoms, X represents an alkyl group having 1 to 20 carbon atoms, an alkynyl group having 1 to 20 carbon atoms, an alkenyl group having 1 to 20 carbon atoms, or an aryl group having 6 to 30 carbon atoms, which may be substituted with a halogen atom and may be branched. 【Chemistry 2】 (In formula (2-a), R １ and R ２ each independently represents a hydrogen atom, a halogen atom, an optionally substituted or branched alkyl group having from 1 to 20 carbon atoms, or an optionally substituted aryl group having from 6 to 30 carbon atoms, X represents an alkyl group having from 1 to 20 carbon atoms, an alkynyl group having from 1 to 20 carbon atoms, an alkenyl group having from 1 to 20 carbon atoms, or an aryl group having from 6 to 30 carbon atoms, which may be branched and may be substituted with a halogen atom; a and b each independently represent an integer of 0 to 3, provided that neither a nor b is 0; m and n each independently represent an integer of 0 to 2; However, the value of (a+m) is an integer of 4 or less, and the value of (b+n) is an integer of 4 or less.

2. The manufacturing method described in claim 1, wherein the purity of the raw material is greater than 99.5 mass%.

3. In the raw material, The concentration of the compound represented by the following formula (3) is 400 mass ppm or less, The concentration of the compound represented by the following formula (4) is 500 mass ppm or less, The concentration of the compound represented by the following formula (5) is 300 ppm by mass or less, or The method according to claim 1 or 2, wherein the concentration of the compound represented by the following formula (6) is 30 ppm by mass or less. 【Chemistry 3】 (In formula (3), i is an integer from 0 to 5.) 【Chemistry 4】 (In formula (4), k is an integer from 0 to 5.) 【Chemistry 5】 (In formula (5), j is an integer from 1 to 5.) 【Chemistry 6】 (The compound of formula (6) is a mixture of the above two compounds or a compound of only one of them.)

4. R in the formulas (1-a) and (2-a) １ , and R ２ is hydrogen, X is a methyl group, The method according to claim 1, wherein a is 1 and b is 0 in the formula (2-a).

5. The method according to any one of claims 1 to 4, wherein the polycarbonate resin has an intrinsic viscosity of 0.2 dl / g or more and 1.0 dl / g or less.

6. In a 7% by mass dichloromethane solution of the polycarbonate resin, ＊ The method according to any one of claims 1 to 5, wherein the value is 2.3 or less.

7. The production method according to any one of claims 1 to 6, further comprising a concentration calculation step of calculating the concentration of the aromatic dihydroxy compound of formula (1-a) and the concentration of the compound of formula (2-a) before the polymerization step.

8. The method according to any one of claims 1 to 7, further comprising an impurity removing step of removing at least a part of the compound of formula (2-a) from the raw material.

9. The method according to any one of claims 1 to 8, wherein in the polymerization step, the aromatic dihydroxy compound of formula (1-a) is polymerized by an interfacial polycondensation method.

10. A molded article comprising a polycarbonate resin obtained by the method according to any one of claims 1 to 9.

11. The molded article according to claim 10, wherein the molded article is a film.

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