Polycarbonate resin and method for producing polycarbonate resin molded article

Abstract

The present invention aims to provide a polycarbonate resin and a manufacturing method for a polycarbonate resin molded product, the polycarbonate resin being excellent in light resistance, transparency, color tone, heat resistance, thermal stability, and mechanical strength. The polycarbonate resin of the present invention contains at least a structural unit derived from a dihydroxy compound having a moiety represented by the following general formula (1) as a partial structure, wherein a case where the moiety represented by the general formula (1) is -CH2-O-H is excluded.

Description

[0001] This application is a divisional application of the invention patent application with application number 201510210492.1, filed on April 29, 2015, entitled "Polycarbonate resin, polycarbonate resin molded article, and method of manufacturing the same".

[0002] The invention patent application with application number 201510210492.1 is a divisional application of the invention patent application with application number 201310296661.9, filed on July 16, 2013, entitled "Polycarbonate Resin and Manufacturing Method Thereof".

[0003] The invention patent application with application number 201310296661.9 is a divisional application of the invention patent application with application number 201080050128.9 (international application number PCT / JP2010 / 071170), international application date of November 26, 2010, entry date into the Chinese national phase of May 4, 2012, and invention title of "polycarbonate resin and manufacturing method thereof". Technical Field

[0004] This invention relates to polycarbonate resins with excellent lightfastness, transparency, hue, heat resistance, thermal stability, and mechanical strength, as well as methods for effectively and stably manufacturing these polycarbonate resins with stable properties. Background Technology

[0005] Polycarbonate resins are typically composed of bisphenols as monomers. Due to their superior properties such as transparency, heat resistance, and mechanical strength, they are widely used as so-called engineering plastics in fields such as electrical and electronic components, automotive components, medical components, building materials, films, sheets, bottles, optical recording media, and lenses.

[0006] However, the color, transparency and mechanical strength of conventional polycarbonate resins deteriorate when used in places where they are exposed to ultraviolet or visible light for extended periods, thus limiting their use outdoors or near lighting fixtures.

[0007] To address this problem, it is well known to add benzophenone-based UV absorbers, benzotriazole-based UV absorbers, or benzoxazine-based UV absorbers to polycarbonate resins (e.g., non-patent literature 1).

[0008] However, while the addition of such UV absorbers has resulted in improvements in color tone and other properties after UV irradiation, it also presents the following problems: it deteriorates the color tone, heat resistance, and transparency of the resin itself, and it volatilizes during molding, causing contamination of the metal mold, etc.

[0009] Bisphenolic compounds, which have been used in polycarbonate resins in the past, have a high UV absorption due to their benzene ring structure. This leads to a deterioration in the lightfastness of polycarbonate resins. Therefore, theoretically, improvements in lightfastness can be expected if monomer units of aliphatic dihydroxy compounds or alicyclic dihydroxy compounds without a benzene ring structure in the molecular backbone, or monomer units of cyclic dihydroxy compounds with ether bonds in the molecule, such as isosorbide, are used. Among these, polycarbonate resins using isosorbide obtained from biological resources as monomers have excellent heat resistance and mechanical strength, and have therefore been extensively studied in recent years (e.g., Patent Documents 1-6).

[0010] However, the aforementioned aliphatic or alicyclic dihydroxy compounds, as well as cyclic dihydroxy compounds with intramolecular ether bonds such as isosorbide, lack phenolic hydroxyl groups. Therefore, they are difficult to polymerize via interfacial methods (interfacial methods are widely known as a method for producing polycarbonate resins from bisphenol A). They are typically manufactured using methods known as transesterification or melt polymerization. In this method, the aforementioned dihydroxy compound is transesterified with a carbonate diester such as diphenyl carbonate in the presence of an alkaline catalyst at a high temperature above 200°C. Phenol and other byproducts generated are removed from the system, and polymerization is then carried out to obtain polycarbonate resin. However, compared to polycarbonate resins obtained using monomers with phenolic hydroxyl groups such as bisphenol A, the aforementioned polycarbonate resins obtained using monomers without phenolic hydroxyl groups have poor thermal stability. Consequently, coloring occurs during polymerization or molding at high temperatures, resulting in poor lightfastness due to absorption of ultraviolet or visible light. In the case of monomers with intramolecular ether bonds such as isosorbide, the color deterioration is significant, requiring substantial improvement.

[0011] On the other hand, as mentioned above, polycarbonate resin is widely used as an engineering plastic in the optical field, such as electrical and electronic components, automotive components, optical recording media, and lenses. The application of optical compensation films for flat panel displays and other products that are rapidly becoming more widespread requires higher optical properties such as low birefringence and low photoelasticity coefficient, which existing aromatic polycarbonates cannot yet meet.

[0012] Furthermore, existing polycarbonates are manufactured using raw materials derived from petroleum resources. However, in recent years, due to concerns about the depletion of petroleum resources, there has been a demand for polycarbonates made from raw materials derived from biological resources such as plants. In addition, due to concerns about climate change caused by increased carbon dioxide emissions and the resulting global warming, there is a demand for the development of polycarbonates made from plant-derived monomers that are carbon neutral even after disposal.

[0013] In this situation, as described in the aforementioned patent documents 1 to 6, a method has been proposed that uses a special dihydroxy compound as a monomer component to remove the byproduct monohydroxy compound generated through transesterification with carbonate by distillation under reduced pressure, thereby simultaneously obtaining polycarbonate.

[0014] However, compared to bisphenols, dihydroxy compounds with such a special structure have a lower boiling point, resulting in severe volatilization during transesterification reactions at high temperatures and reduced pressures. This not only leads to a deterioration in the yield per unit of raw material, but also presents the problem of difficulty in controlling the concentration of terminal groups, which can affect quality, to a predetermined value. Furthermore, when using two or more dihydroxy compounds, the molar ratio of the dihydroxy compounds used will change during polymerization, resulting in the inability to obtain polycarbonate resins with the desired molecular weight and composition.

[0015] To address this problem, methods such as lowering the polymerization temperature and reducing the pressure reduction have been considered. However, while monomer volatilization is suppressed in these methods, they still present the dilemma of reduced productivity.

[0016] In addition, methods using polymerization reactors with specific reflux coolers have been proposed (see, for example, Patent Document 7), but the improvement of the feed unit has not yet reached a satisfactory level, and further improvements are required.

[0017] Furthermore, the byproduct monohydroxy compounds lose a significant amount of latent heat of vaporization during distillation, thus requiring heating with a heating medium to maintain the predetermined polymerization temperature. However, using larger reactors reduces the heat transfer area per unit volume of reaction liquid, necessitating the use of a higher-temperature heating medium. This means that the portion of the reaction liquid in contact with the wall where the heating medium flows is heated at a higher temperature, significantly accelerating the volatilization of low-boiling-point dihydroxy compounds in contact with that wall and causing thermal degradation near that wall, leading to quality deterioration. This problem is exacerbated with larger reactors.

[0018] Existing technical documents

[0019] Patent documents

[0020] Patent Document 1: International Publication No. 04 / 111106

[0021] Patent Document 2: Japanese Patent Application Publication No. 2006-232897

[0022] Patent Document 3: Japanese Patent Application Publication No. 2006-28441

[0023] Patent Document 4: Japanese Patent Application Publication No. 2008-24919

[0024] Patent Document 5: Japanese Patent Application Publication No. 2009-91404

[0025] Patent Document 6: Japanese Patent Application Publication No. 2009-91417

[0026] Patent Document 7: Japanese Patent Application Publication No. 2008-56844

[0027] Non-patent literature

[0028] Non-Patent Document 1: Edited by Seiichi Honma, *Polycarbonate Resin Handbook*, Nikkan Kogyo Shinbunsha, August 28, 1992 Summary of the Invention

[0029] The problem that the invention aims to solve

[0030] The purpose of this invention is to eliminate the aforementioned problems and provide a polycarbonate resin with excellent lightfastness, transparency, color tone, heat resistance, thermal stability, and mechanical strength.

[0031] In addition, another object of the present invention is to eliminate the aforementioned existing problems and provide a method for effectively and stably manufacturing polycarbonate resins with excellent and stable performance in terms of lightfastness, transparency, hue, heat resistance, thermal stability and mechanical strength.

[0032] Methods for solving problems

[0033] In order to solve the above-mentioned problems, the inventors conducted in-depth research and found that polycarbonate resins with the following general formula (1) in the molecule and a transmittance of a specific wavelength of more than a certain value not only have excellent light resistance, but also excellent transparency, color tone, heat resistance, thermal stability and mechanical strength, thereby completing the first aspect of the present invention.

[0034] That is, the first aspect of the present invention is as described below [1] to

[16] .

[0035] [1] A polycarbonate resin containing at least a structural unit derived from a dihydroxy compound having a portion of the structure shown in the following general formula (1), wherein a molded body (thickness 3 mm) formed from the polycarbonate resin has a light transmittance of 60% or more at a wavelength of 350 nm.

[0036] [Chemistry 1]

[0037]

[0038] (This excludes cases where the part shown in the above general formula (1) is part of -CH2-OH.)

[0039] [2] The polycarbonate resin described in [1] above, wherein the molded body (thickness 3 mm) formed from the polycarbonate resin has a light transmittance of 30% or more at a wavelength of 320 nm.

[0040] [3] The polycarbonate resin as described in [1] or [2] above, wherein a molded body (thickness 3 mm) is formed from the polycarbonate resin, and an irradiance of 1.5 kW / m² at a wavelength of 300 nm to 400 nm is applied using a metal halide lamp in an environment of 63°C and 50% relative humidity. 2 After the molded body was irradiated for 100 hours, the yellow index (YI) value based on ASTM D1925-70, measured using transmitted light, was below 12.

[0041] [4] The polycarbonate resin as described in any of [1] to [3] above, wherein the initial yellow index value of the molded body (thickness 3 mm) formed from the polycarbonate resin is 10 or less.

[0042] [5] The polycarbonate resin as described in any one of [1] to [4] above, wherein the absolute value of the difference between the initial yellow index value of the molded body (thickness 3 mm) formed from the above polycarbonate resin and the yellow index (YI) value obtained below is 6 or less, wherein the yellow index (YI) value is obtained by using a metal halide lamp with an irradiance of 1.5 kW / m at a wavelength of 300 nm to 400 nm in an environment of 63°C and 50% relative humidity. 2 After the molded body was irradiated for 100 hours, the yellow index (YI) value based on ASTM D1925-70 was measured using transmitted light.

[0043] [6] The polycarbonate resin as described in any one of [1] to [5] above, wherein the L* value of the molded body (thickness 3 mm) formed from the polycarbonate resin is 96.3 or more.

[0044] [7] The polycarbonate resin as described in any one of [1] to [6] above, wherein the polycarbonate resin contains less than 60 ppm by weight of the following general formula (2) of the following general formula.

[0045] [Chemistry 2]

[0046]

[0047] (In general formula (2), A) 1 and A 2 Each group is independently an aliphatic group with 1 to 18 carbon atoms, either substituted or unsubstituted, or an aromatic group, either substituted or unsubstituted.

[0048] [8] The polycarbonate resin as described in any one of [1] to [7] above, wherein the polycarbonate resin contains less than 700 ppm by weight of an aromatic monohydroxy compound.

[0049] [9] The polycarbonate resin as described in any of [1] to [8] above, wherein the total content of sodium, potassium and cesium in the polycarbonate resin is less than 1 ppm by weight in terms of metal content.

[0050]

[10] The polycarbonate resin as described in any of [1] to [9] above, wherein the concentration of the terminal group represented by the following general formula (3) in the polycarbonate resin is 20 μeq / g or more and 160 μeq / g or less.

[0051] [Chemistry 3]

[0052]

[0053]

[11] The polycarbonate resin described in any of [1] to

[10] above, wherein when the number of moles of H bonded to the aromatic ring in the polycarbonate resin is set as (A) and the number of moles of H bonded to the portion other than the aromatic ring is set as (B), A / (A+B)≦0.1.

[0054]

[12] The polycarbonate resin described in any of [1] to

[11] above, wherein the dihydroxy compound having the portion of the above general formula (1) as a part of the structure is the dihydroxy compound shown in the following general formula (4).

[0055] [Chemistry 4]

[0056]

[0057]

[13] The polycarbonate resin described in any of [1] to

[12] above further contains a structural unit derived from at least one compound selected from the group consisting of aliphatic dihydroxy compounds and alicyclic dihydroxy compounds.

[0058]

[14] The polycarbonate resin described in any of [1] to

[13] above is obtained by polycondensation of a dihydroxy compound having the part of the above general formula (1) as a partial structure with a carbonate diester shown in the following general formula (2) in the presence of a catalyst.

[0059] [Chemistry 5]

[0060]

[0061] (In general formula (2), A) 1 and A 2Each group is independently an aliphatic group with 1 to 18 carbon atoms, either substituted or unsubstituted, or an aromatic group, either substituted or unsubstituted.

[0062]

[15] The polycarbonate resin as described in

[14] above, wherein the catalyst is at least one metal compound selected from the group consisting of lithium and long-period group 2 metals of the periodic table, and the total amount of these compounds is less than 20 μmol of dihydroxy compound per mol of metal.

[0063]

[16] The polycarbonate resin as described in any of [1] to

[14] above, wherein the polycarbonate resin is obtained using at least one metal compound selected from the group consisting of magnesium compounds and calcium compounds as a catalyst, and the total content of lithium, sodium, potassium and cesium in the polycarbonate resin is less than 1 ppm by weight in terms of metal content.

[0064] The inventors further conducted in-depth research and found that polycarbonate resins with the structure shown in the following general formula (1) in the molecule and a transmittance of a specific wavelength above a certain value not only have excellent light resistance, but also excellent transparency, color tone, heat resistance, thermal stability and mechanical strength, thus completing the second aspect of the present invention.

[0065] That is, the second aspect of the present invention is as described below

[17] to

[20] .

[0066]

[17] A polycarbonate resin, which is a polycarbonate resin containing at least structural units derived from dihydroxy compounds having the portion shown in the following general formula (1) as a partial structure, wherein a molded body (thickness 3 mm) is formed from the polycarbonate resin and subjected to irradiance of 1.5 kW / m² at a wavelength of 300 nm to 400 nm using a metal halide lamp in an environment of 63°C and 50% relative humidity. 2 After the molded body was irradiated for 100 hours, the yellow index (YI) value based on ASTM D1925-70, measured using transmitted light, was below 12.

[0067] [Chemistry 6]

[0068]

[0069] (This excludes cases where the part shown in the above general formula (1) is part of -CH2-OH.)

[0070]

[18] The polycarbonate resin described in

[17] above, wherein the initial yellow index value of the molded body (thickness 3 mm) formed from the polycarbonate resin is 10 or less.

[0071]

[19] The polycarbonate resin as described in

[17] or

[18] above, wherein the absolute value of the difference between the initial yellow index value of the molded body (thickness 3 mm) formed from the above polycarbonate resin and the yellow index (YI) value obtained below is 6 or less, wherein the yellow index (YI) value is obtained by using a metal halide lamp with an irradiance of 1.5 kW / m at a wavelength of 300 nm to 400 nm in an environment of 63°C and 50% relative humidity. 2 After the molded body was irradiated for 100 hours, the yellow index (YI) value based on ASTM D1925-70 was measured using transmitted light.

[0072]

[20] The polycarbonate resin described in any of

[17] to

[19] above, wherein the molded body (thickness 3 mm) formed from the polycarbonate resin has a light transmittance of 60% or more at a wavelength of 350 nm.

[0073] The inventors further conducted in-depth research and found that the following polycarbonate resin not only has excellent lightfastness, but also excellent transparency, hue, heat resistance, thermal stability and mechanical strength, thus completing the third aspect of the present invention; the polycarbonate resin is a polycarbonate resin obtained by polycondensation of a dihydroxy compound having a dihydroxy compound having a part of the structure shown in the following general formula (1) and a carbonate diester shown in the following general formula (2) in the presence of a catalyst, wherein the catalyst is a compound containing at least one metal selected from the group consisting of lithium and long-period type periodic table group 2, and the polycarbonate resin is a polycarbonate resin containing an amount of the metal-containing compound of 20 μmol or less relative to 1 mol of the dihydroxy compound and containing an aromatic monohydroxy compound of 700 ppm by weight or less.

[0074] That is, the third aspect of the present invention is as described below

[21] to

[34] .

[0075]

[21] A polycarbonate resin, which is a polycarbonate resin obtained by polycondensation of a dihydroxy compound having a part of the structure shown in the following general formula (1) and a carbonate diester shown in the following general formula (2) in the presence of a catalyst, wherein the catalyst is a compound containing at least one metal selected from the group consisting of lithium and long-period type periodic table group 2, the amount of the compound containing the metal is 20 μmol or less relative to 1 mol of the dihydroxy compound, and the polycarbonate resin contains 700 ppm by weight of an aromatic monohydroxy compound.

[0076] [Chemistry 7]

[0077]

[0078] (This excludes cases where the part shown in the above general formula (1) is part of -CH2-OH.)

[0079] [Chemistry 8]

[0080]

[0081] (In general formula (2), A) 1 and A 2 Each group is independently an aliphatic group with 1 to 18 carbon atoms, either substituted or unsubstituted, or an aromatic group, either substituted or unsubstituted.

[0082]

[22] The polycarbonate resin as described in

[21] above, wherein the catalyst is at least one metal compound selected from the group consisting of magnesium compounds and calcium compounds.

[0083]

[23] The polycarbonate resin as described in

[21] or

[22] above, wherein the total amount of sodium, potassium and cesium in the polycarbonate resin is less than 1 ppm by weight in terms of metal content.

[0084]

[24] The polycarbonate resin as described in any of

[21] to

[23] above, wherein the total amount of lithium, sodium, potassium and cesium in the polycarbonate resin is less than 1 ppm by weight in terms of metal content.

[0085]

[25] The polycarbonate resin as described in any of

[21] to

[24] above, wherein the polycarbonate resin contains less than 60 ppm by weight of the diester of the above general formula (2).

[0086]

[26] The polycarbonate resin described in any of

[21] to

[25] above, wherein the dihydroxy compound having the portion of the above general formula (1) as part of the structure is the compound shown in the following general formula (4).

[0087] [Chemistry 9]

[0088]

[0089]

[27] The polycarbonate resin as described in any one of

[21] to

[26] above, wherein the polycarbonate resin contains structural units derived from a dihydroxy compound having the portion of the above general formula (1) as a partial structure, and structural units derived from at least one compound selected from the group consisting of aliphatic dihydroxy compounds and alicyclic dihydroxy compounds.

[0090]

[28] The polycarbonate resin as described in any of

[21] to

[27] above, wherein the concentration of the terminal group represented by the following general formula (3) in the polycarbonate resin is 20 μeq / g or more and 160 μeq / g or less.

[0091] [Chemistry 10]

[0092]

[0093]

[29] The polycarbonate resin described in any of

[21] to

[28] above, wherein when the number of moles of H bonded to the aromatic ring in the polycarbonate resin is set as (A) and the number of moles of H bonded to the portion other than the aromatic ring is set as (B), A / (A+B)≦0.1.

[0094]

[30] The polycarbonate resin described in any of

[21] to

[29] above, wherein the molded body (thickness 3 mm) formed from the polycarbonate resin has a light transmittance of 60% or more at a wavelength of 350 nm.

[0095]

[31] The polycarbonate resin as described in any of

[21] to

[30] above, wherein the molded body (thickness 3 mm) formed from the polycarbonate resin has a light transmittance of 30% or more at a wavelength of 320 nm.

[0096]

[32] The polycarbonate resin as described in any one of

[21] to

[31] above, wherein a molded body (thickness 3 mm) is formed from the polycarbonate resin, and an irradiance of 1.5 kW / m² at a wavelength of 300 nm to 400 nm is applied using a metal halide lamp at an environment of 63°C and 50% relative humidity. 2 After the molded body was irradiated for 100 hours, the yellow index (YI) value based on ASTM D1925-70, measured using transmitted light, was below 12.

[0097]

[33] The polycarbonate resin as described in any of

[21] to

[32] above, wherein the initial yellow index value of the molded body (thickness 3 mm) formed from the polycarbonate resin is 10 or less.

[0098]

[34] The polycarbonate resin as described in any one of

[21] to

[33] , wherein the absolute value of the difference between the initial yellow index value of the molded body (thickness 3 mm) formed from the above-described polycarbonate resin and the yellow index (YI) value obtained below is 6 or less, wherein the yellow index (YI) value is obtained by using a metal halide lamp at an irradiance of 1.5 kW / m² with a wavelength of 300 nm to 400 nm in an environment of 63°C and 50% relative humidity. 2After the molded body was irradiated for 100 hours, the yellow index (YI) value based on ASTM D1925-70 was measured using transmitted light.

[0099] Furthermore, in order to solve the above-mentioned problems, the present invention is preferably as shown below

[35] and

[36] .

[0100]

[35] A polycarbonate resin molded article, which is obtained by molding the polycarbonate resin described in any one of [1] to

[34] above.

[0101]

[36] The polycarbonate resin molded article as described in

[35] above, wherein the polycarbonate resin molded article is obtained by injection molding.

[0102] Furthermore, the inventors conducted repeated and in-depth research and discovered a method for manufacturing polycarbonate resin. This method involves using diester and dihydroxy compound as monomers to perform polycondensation via transesterification to manufacture polycarbonate resin. This method produces polycarbonate resin with excellent lightfastness, transparency, hue, heat resistance, thermal stability, and mechanical strength by keeping the monomer distilled from the reactor below a specific amount. This completes the fourth aspect of the present invention.

[0103] That is, the fourth aspect of the present invention is as described below

[37] to

[53] .

[0104]

[37] A method for manufacturing polycarbonate resin, comprising using a catalyst and diester and dihydroxy compound as raw material monomers, and employing two or more reactors to polycondense the raw material monomers through a multi-stage transesterification reaction to manufacture polycarbonate resin, wherein:

[0105] The dihydroxy compound includes at least a dihydroxy compound having a portion of the structure shown in the following general formula (1);

[0106] At least one of the reactors that distills the monohydroxy compound, a byproduct of transesterification, at a rate of 20% or more of the theoretical distillate is a reactor having an internal volume of 20 L or more and equipped with a heating unit and a reflux cooler. The heating unit is used to heat the reactor using a heating medium, the temperature of which differs from the temperature of the reaction liquid in the reactor by at least 5 °C.

[0107] The total amount of monomer distilled off during the entire reaction process is less than 10% by weight relative to the total amount of raw monomer.

[0108] [Chemistry 11]

[0109]

[0110] (This excludes cases where the part shown in the above general formula (1) is part of -CH2-OH.)

[0111]

[38] A method for manufacturing polycarbonate resin, comprising using a catalyst and diester and dihydroxy compound as raw material monomers, and using two or more reactors to polycondense the raw material monomers through a multi-stage transesterification reaction to manufacture polycarbonate resin, wherein:

[0112] The dihydroxy compound includes two or more dihydroxy compounds, at least one of which is a dihydroxy compound having the part of the structure shown in the following general formula (1);

[0113] At least one of the reactors that distills the monohydroxy compound, a byproduct of transesterification, at a rate of 20% or more of the theoretical distillate is a reactor having an internal volume of 20 L or more and equipped with a heating unit and a reflux cooler. The heating unit is used to heat the reactor using a heating medium, the temperature of which differs from the temperature of the reaction liquid in the reactor by at least 5 °C.

[0114] The absolute value of the difference of the following molar percentages divided by the molar percentage of the dihydroxy compound at the time of feeding is less than 0.03 for at least one dihydroxy compound and not greater than 0.05 for any one dihydroxy compound. The difference of molar percentages is the difference between the molar percentage of the dihydroxy compound at the time of feeding into the reactor as a raw material and the molar percentage of the dihydroxy compound structural unit in the obtained polycarbonate resin.

[0115] [Chemistry 12]

[0116]

[0117] (This excludes cases where the part shown in the above general formula (1) is part of -CH2-OH.)

[0118]

[39] The method for manufacturing polycarbonate resin as described in

[37] or

[38] above, wherein at least one of the dihydroxy compounds has a boiling point of 300°C or less at atmospheric pressure.

[0119]

[40] The method for manufacturing polycarbonate resin as described in any of

[37] to

[39] above uses at least three reactors.

[0120]

[41] The method for manufacturing polycarbonate resin as described in any of

[37] to

[40] above, wherein the temperature of the refrigerant introduced into the reflux cooler is 45°C to 180°C at the inlet of the reflux cooler.

[0121]

[42] The method for manufacturing polycarbonate resin as described in any of

[37] to

[41] above, wherein the total amount of monomers distilled off in all reaction stages is less than 3% by weight relative to the total amount of raw material monomers.

[0122]

[43] In the method for manufacturing polycarbonate resin as described in any of

[37] to

[42] above, in the first reactor in which the monohydroxy compound by-product of the transesterification reaction is distilled out at a distillation amount of 20% or more of the theoretical distillation amount, at least one metal compound selected from the group consisting of lithium and long-period group 2 metals of the periodic table is used as a catalyst, and the amount of the metal compound used in the first reactor is 20 μmol or less relative to 1 mol of all dihydroxy compounds used as raw materials, based on the total amount of its metal atoms.

[0123]

[44] The method for manufacturing polycarbonate resin as described in

[43] above, wherein the catalyst is at least one metal compound selected from the group consisting of magnesium compounds and calcium compounds.

[0124]

[45] The method for manufacturing polycarbonate resin as described in any of

[37] to

[44] above, wherein the highest temperature of the reaction solution is less than 250°C throughout the entire reaction phase.

[0125]

[46] The method for manufacturing polycarbonate resin as described in any of

[37] to

[45] above, wherein the maximum temperature of the heating medium is less than 265°C.

[0126]

[47] The method for manufacturing polycarbonate resin as described in any of

[37] to

[46] above, wherein the dihydroxy compound includes a compound of the following general formula (4) and at least one compound selected from the group consisting of aliphatic dihydroxy compounds and alicyclic dihydroxy compounds.

[0127] [Chemistry 13]

[0128]

[0129]

[48] ​​A polycarbonate resin obtained by the method described in any one of

[37] to

[47] above, wherein the molded body (thickness 3 mm) formed from the polycarbonate resin has a light transmittance of 60% or more at a wavelength of 350 nm.

[0130]

[49] A polycarbonate resin obtained by the method described in any one of

[37] to

[47] above, wherein the molded body (thickness 3 mm) formed from the polycarbonate resin has a light transmittance of 30% or more at a wavelength of 320 nm.

[0131]

[50] A polycarbonate resin, which is obtained by the method described in any one of

[37] to

[47] above, wherein a molded body (thickness 3 mm) is formed from the polycarbonate resin and subjected to irradiance of 1.5 kW / m² at a wavelength of 300 nm to 400 nm using a metal halide lamp in an environment of 63°C and 50% relative humidity. 2 After the molded body was irradiated for 100 hours, the yellow index (YI) value based on ASTM D1925-70, measured using transmitted light, was below 12.

[0132]

[51] A polycarbonate resin, which is obtained by the method described in any one of

[37] to

[47] above, wherein the initial yellow index value of the molded body (thickness 3 mm) formed from the polycarbonate resin is 10 or less.

[0133]

[52] A polycarbonate resin obtained by the method described in any one of

[37] to

[47] above, wherein the absolute value of the difference between the initial yellow index value of the molded body (thickness 3 mm) formed from the polycarbonate resin and the following yellow index (YI) value is 6 or less, wherein the yellow index (YI) value is obtained by using a metal halide lamp with an irradiance of 1.5 kW / m at a wavelength of 300 nm to 400 nm in an environment of 63°C and 50% relative humidity. 2 After the molded body was irradiated for 100 hours, the yellow index (YI) value based on ASTM D1925-70 was measured using transmitted light.

[0134]

[53] A polycarbonate resin obtained by the method described in any one of

[37] to

[47] above, wherein the L* value of the molded body (thickness 3 mm) formed from the polycarbonate resin is 96.3 or more.

[0135] Invention Effects

[0136] This invention provides a polycarbonate resin that not only possesses excellent lightfastness, but also excellent transparency, hue, heat resistance, thermal stability, moldability, and mechanical strength. Thus, it provides a polycarbonate resin suitable for a wide range of applications, including: injection molding applications for electrical and electronic components, automotive components, etc.; film and sheet applications; bottle and container applications; lens applications such as camera lenses, aiming lenses, CCD, and CMOS lenses; phase retardation films, diffusers, polarizing films, etc., used in liquid crystal or plasma displays; optical discs, optical materials, and optical components; adhesives for immobilizing pigments and charge transfer agents; and more particularly, a polycarbonate resin suitable for outdoor and lighting applications exposed to ultraviolet light, etc.

[0137] Furthermore, the present invention can effectively and stably manufacture the above-mentioned polycarbonate resin. Detailed Implementation

[0138] The embodiments of the present invention will be described in detail below. However, the following description of the technical features is only one example (representative example) of the embodiments of the present invention. The present invention is not limited to the following content as long as it does not go beyond its essential points.

[0139] · First polycarbonate resin

[0140] The first polycarbonate resin of the present invention is a polycarbonate resin containing at least structural units derived from dihydroxy compounds having a portion of the structure shown in the following general formula (1), characterized in that the molded article (3 mm thick) formed from the polycarbonate resin has a light transmittance of 60% or more at a wavelength of 350 nm. The light transmittance at this wavelength is preferably 65% ​​or more, particularly preferably 70% or more. If the light transmittance at this wavelength is less than 60%, absorption increases, and lightfastness may deteriorate.

[0141] [Chemistry 14]

[0142]

[0143] (This excludes cases where the part shown in the above general formula (1) is part of -CH2-OH.)

[0144] This is based on the following insight: it has been discovered that even when a resin does not absorb visible light and its coloration is not detected by the human eye, some resins will color when exposed to sunlight, artificial lighting, etc., while others will not. It was also unexpectedly discovered that this problem can be solved by making the transmittance of light of a specific wavelength exceed a certain value.

[0145] Furthermore, in the first polycarbonate resin of the present invention, the molded body (a flat plate with a thickness of 3 mm) formed from the resin preferably has a light transmittance of 30% or more, more preferably 40% or more, and particularly preferably 50% or more at a wavelength of 320 nm. If the light transmittance at this wavelength is less than 30%, the lightfastness may deteriorate.

[0146] In the first polycarbonate resin of the present invention, a molded body (a flat plate with a thickness of 3 mm) is formed from the resin, and subjected to irradiance of 1.5 kW / m² at a wavelength of 300 nm to 400 nm using a metal halide lamp in an environment of 63°C and 50% relative humidity. 2 After the molded body is subjected to 100 hours of irradiation treatment, the yellow index (YI) value based on ASTM D1925-70, measured using transmitted light, is preferably 12 or less, more preferably 10 or less, and particularly preferably 8 or less. If the yellow index (YI) value is greater than 12, coloring may occur even if the body is not colored immediately after molding, when exposed to light containing ultraviolet light.

[0147] It should be noted that the irradiation treatment using a metal halide lamp in this invention refers to, as described later, employing a specific device and a specific filter to irradiate light with wavelengths primarily between 300nm and 400nm (while minimizing the removal of wavelengths outside this range) at an irradiance of 1.5kW / m². 2 The sample was irradiated for 100 hours.

[0148] Furthermore, regarding the first polycarbonate resin of the present invention, when a plate with a thickness of 3 mm is formed from the resin, and the plate is not subjected to the metal halide lamp irradiation treatment as described above, the yellow index value (i.e., the initial yellow index value, referred to as the initial YI value) measured by transmitted light on the plate is generally preferably 10 or less, more preferably 7 or less, and particularly preferably 5 or less. Moreover, the absolute value of the difference between the yellow index values ​​before and after metal halide lamp irradiation is preferably 6 or less, more preferably 4 or less, and particularly preferably 3 or less.

[0149] If the initial yellow index (YI) value is greater than 10, the lightfastness may deteriorate. In addition, if the absolute value of the difference between the yellow index (YI) values ​​before and after metal halide lamp irradiation is greater than 6, the resin will become discolored after prolonged exposure to sunlight, artificial lighting, etc., and may not be usable in applications where transparency is particularly required.

[0150] Furthermore, for the first polycarbonate resin of the present invention, when the resin is molded into a plate with a thickness of 3 mm, the L* value specified by the International Commission on Illumination (CIE) and measured using transmitted light is preferably 96.3 or higher, more preferably 96.6 or higher, and suitablely 96.8 or higher. If the L* value is lower than 96.3, the lightfastness may deteriorate.

[0151] ·Second polycarbonate resin

[0152] The second polycarbonate resin of the present invention is a polycarbonate resin containing at least structural units derived from dihydroxy compounds having the portion shown in the following general formula (1) as a partial structure, characterized in that a molded body (thickness 3 mm) is formed from the polycarbonate resin and subjected to irradiance of 1.5 kW / m² at a wavelength of 300 nm to 400 nm using a metal halide lamp in an environment of 63°C and 50% relative humidity. 2 After the molded body is subjected to 100 hours of irradiation treatment, the yellow index (YI) value of the molded body, measured using transmitted light based on ASTM D1925-70, is 12 or less. This yellow index (YI) value is preferably 10 or less, and particularly preferably 8 or less.

[0153] [Chemistry 15]

[0154]

[0155] (This excludes cases where the part shown in the above general formula (1) is part of -CH2-OH.)

[0156] This is based on the following insight: it has been found that if the aforementioned metal halide lamps are used at a wavelength of 300nm–400nm with an irradiance of 1.5kW / m², 2 If the yellow index (YI) value measured after 100 hours of irradiation treatment is greater than 12 based on ASTM D1925-70, then even if it is not colored immediately after molding, it may become colored when exposed to light containing ultraviolet light. It was also unexpectedly discovered that this problem can be solved by controlling the heat history experienced in the transesterification reaction (i.e., polycondensation reaction), the catalyst used, the metal components contained, and the content of substances with specific molecular structures.

[0157] Furthermore, in the second polycarbonate resin of the present invention, a plate with a thickness of 3 mm is formed from the polycarbonate resin, and the plate is not subjected to the metal halide lamp irradiation treatment as described above. The yellow index value (i.e., the initial yellow index value, referred to as the initial YI value) of the plate measured by transmitted light is generally preferably 10 or less, more preferably 7 or less, and particularly preferably 5 or less. Moreover, the absolute value of the difference between the yellow index values ​​before and after metal halide lamp irradiation is preferably 6 or less, more preferably 4 or less, and particularly preferably 3 or less.

[0158] If the initial yellow index (YI) value is greater than 10, the lightfastness may deteriorate. In addition, if the absolute value of the difference between the yellow index (YI) values ​​before and after metal halide lamp irradiation is greater than 6, the resin will become discolored after prolonged exposure to sunlight, artificial lighting, etc., and may not be usable in applications where transparency is particularly required.

[0159] Regarding the second polycarbonate resin of the present invention, the molded body (3 mm thick) formed from this resin preferably has a light transmittance of 60% or more, more preferably 65% ​​or more, and particularly preferably 70% or more at a wavelength of 350 nm. If the light transmittance at this wavelength is less than 60%, the absorption increases, and the light resistance may deteriorate.

[0160] Furthermore, regarding the second polycarbonate resin of the present invention, the light transmittance of the molded body (a flat plate with a thickness of 3 mm) formed from this resin at a wavelength of 320 nm is preferably 30% or more, more preferably 40% or more, and particularly preferably 50% or more. If the light transmittance at this wavelength is less than 30%, the lightfastness may deteriorate.

[0161] Furthermore, regarding the second polycarbonate resin of the present invention, when the resin is molded into a 3 mm thick plate, the L* value specified by the International Commission on Illumination (CIE) and measured using transmitted light is preferably 96.3 or higher, more preferably 96.6 or higher, and suitablely 96.8 or higher. If the L* value is lower than 96.3, the lightfastness may deteriorate.

[0162] ·Third polycarbonate resin

[0163] The third polycarbonate resin of the present invention is a polycarbonate resin obtained by polycondensation of a dihydroxy compound with a carbonate diester of the following general formula (2) in the presence of a catalyst. The dihydroxy compound is a dihydroxy compound containing a part having the site shown in the following general formula (1) as a partial structure. The catalyst is a compound of at least one metal selected from the group consisting of lithium and long-period type group 2 of the periodic table. The amount of the metal compound is 20 μmol or less relative to 1 mol of the dihydroxy compound, and the polycarbonate resin contains 700 ppm or less of an aromatic monohydroxy compound by weight.

[0164] [Chemistry 16]

[0165]

[0166] (This excludes cases where the part shown in the above general formula (1) is part of -CH2-OH.)

[0167] [Chemistry 17]

[0168]

[0169] (In general formula (2), A) 1 and A 2 Each group is independently an aliphatic group with 1 to 18 carbon atoms, either substituted or unsubstituted, or an aromatic group, either substituted or unsubstituted.

[0170] The third polycarbonate resin of the present invention is prepared by polycondensation of a dihydroxy compound including the aforementioned specific dihydroxy compound and a diester in the presence of a specific catalyst in a specific amount. By keeping the content of the aromatic monohydroxy compound below a specific amount, a polycarbonate resin with excellent lightfastness, transparency, hue, heat resistance, thermal stability, and mechanical strength is obtained. In particular, regarding lightfastness, absorption in the visible light region has been noted previously. However, the inventors have discovered that even when the resin does not absorb visible light and the coloring is not perceptible to the human eye, some resins will color under exposure to sunlight, artificial lighting, etc., while others will not color, thus completing the present invention.

[0171] Furthermore, regarding the third polycarbonate resin of the present invention, the light transmittance of the molded body (3 mm thick) formed from this polycarbonate resin at a wavelength of 350 nm is preferably 60% or more, more preferably 65% ​​or more, and particularly preferably 70% or more. If the light transmittance at this wavelength is less than 60%, the absorption increases, and the light resistance may deteriorate.

[0172] Furthermore, regarding the third polycarbonate resin of the present invention, the light transmittance of the molded body (3 mm thick) formed from this polycarbonate resin at a wavelength of 320 nm is preferably 30% or more, more preferably 40% or more, and particularly preferably 50% or more. If the light transmittance at this wavelength is less than 30%, the lightfastness may deteriorate.

[0173] Regarding the third polycarbonate resin of the present invention, a molded body (3 mm thick) is formed from this polycarbonate resin and subjected to irradiance of 1.5 kW / m² at a wavelength of 300 nm to 400 nm using a metal halide lamp in an environment of 63°C and 50% relative humidity. 2After the molded body is subjected to 100 hours of irradiation treatment, the yellow index (YI) value based on ASTM D1925-70, measured using transmitted light, is preferably 12 or less, more preferably 10 or less, and particularly preferably 8 or less. If the yellow index (YI) value is greater than 12, coloring may occur even if the body is not colored immediately after molding, when exposed to light containing ultraviolet light.

[0174] Furthermore, regarding the third polycarbonate resin of the present invention, when a molded body (3 mm thick) is formed from this polycarbonate resin, and the molded body is not subjected to the metal halide lamp irradiation treatment as described above, the yellow index value (i.e., the initial yellow index value, referred to as the initial YI value) of the molded body measured using transmitted light is generally preferably 10 or less, more preferably 7 or less, and particularly preferably 5 or less. Moreover, the absolute value of the difference between the yellow index values ​​before and after metal halide lamp irradiation is preferably 6 or less, more preferably 4 or less, and particularly preferably 3 or less.

[0175] If the initial yellow index (YI) value is greater than 10, the lightfastness tends to deteriorate. In addition, if the absolute value of the difference between the yellow index (YI) values ​​before and after metal halide lamp irradiation is greater than 6, the resin will become discolored after prolonged exposure to sunlight, artificial lighting, etc., and may not be usable in applications where transparency is particularly required.

[0176] Furthermore, regarding the third polycarbonate resin of the present invention, the L* value (3 mm thick) of the molded body formed from this polycarbonate resin, as specified by the International Commission on Illumination (CIE) and measured using transmitted light, is generally preferably 96.3 or higher, more preferably 96.6 or higher, and particularly preferably 96.8 or higher. If the L* value is lower than 96.3, the lightfastness may deteriorate.

[0177] The first to third polycarbonate resins described above (hereinafter also referred to as "the polycarbonate resins of the present invention") can exert the effects of the present invention. Such polycarbonate resins can be manufactured, for example, by limiting the concentration of specific metals during polymerization; appropriately selecting the type and amount of catalyst; appropriately selecting the temperature and time during polymerization; reducing compounds with ultraviolet absorption capabilities in the resin (e.g., residual phenol, residual diphenyl carbonate); reducing the amount of substances with ultraviolet absorption as raw material monomers; reducing the amount of substances with ultraviolet absorption as impurities in the raw materials; and so on. In particular, the type and amount of catalyst, and the temperature and time during polymerization are important.

[0178] The method for manufacturing the polycarbonate resin of the present invention will now be described in detail.

[0179] <Ingredients>

[0180] (Dihydroxy compound)

[0181] The polycarbonate resin of the present invention contains at least a structural unit derived from a dihydroxy compound having a portion of the structure shown in the following general formula (1) (hereinafter also referred to as "the dihydroxy compound of the present invention"). That is, the dihydroxy compound of the present invention refers to a compound containing at least two hydroxyl groups and a structural unit of the following general formula (1).

[0182] [Chemistry 18]

[0183]

[0184] (This excludes cases where the part shown in the above general formula (1) is part of -CH2-OH.)

[0185] As the dihydroxy compound of the present invention, there is no particular limitation as long as the part shown in the above general formula (1) is included as a partial structure. Specifically, examples include: diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, and other oxyalkylene glycols; 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-) ... Compounds having aromatic groups in the side chain and ether groups bonded to the aromatic groups in the main chain, such as fluorene (hydroxyethoxy)-3,5-dimethylphenyl), 9,9-bis(4-(2-hydroxyethoxy)-3-tert-butyl-6-methylphenyl), and 9,9-bis(4-(3-hydroxy-2,2-dimethylpropoxy)phenyl)fluorene; anhydrous sugar alcohols represented by dihydroxy compounds of the following general formula (4); and compounds having cyclic ether structures, such as spirocyclic diols of the following general formula (5). Among these, diethylene glycol and triethylene glycol are preferred from the perspectives of ease of acquisition, processing, reactivity during polymerization, and the color of the resulting polycarbonate resin. From the perspective of heat resistance, anhydrous sugar alcohols represented by dihydroxy compounds of the following general formula (4) and compounds having cyclic ether structures of the following general formula (5) are preferred.

[0186] Depending on the required properties of the obtained polycarbonate resin, these dihydroxy compounds can be used alone or in combination of two or more.

[0187] [Chemistry 19]

[0188]

[0189] [Chemistry 20]

[0190]

[0191] As dihydroxy compounds represented by the above general formula (4), examples include isosorbide, isomannitol, and iso-idole, which are spatial isomers. They can be used alone or in combination of two or more.

[0192] Among these dihydroxy compounds, from the perspective of the lightfastness of the polycarbonate resin of the present invention, dihydroxy compounds without aromatic ring structures are preferred. Isosorbide is obtained by dehydrating and condensing sorbitol, which is produced from various starches. Starch is an abundant and readily available plant-derived resource. Isosorbide is most preferred from the perspectives of ease of acquisition and manufacture, lightfastness, optical properties, moldability, heat resistance, and carbon neutrality.

[0193] The polycarbonate resin of the present invention may also contain structural units derived from dihydroxy compounds other than those described above (hereinafter sometimes referred to as "other dihydroxy compounds"). Examples of other dihydroxy compounds include, for instance, aliphatic dihydroxy compounds such as ethylene glycol, 1,3-propanediol, 1,2-propanediol, 1,4-butanediol, 1,3-butanediol, 1,2-butanediol, 1,5-heptanediol, and 1,6-hexanediol; and 1,2-cyclohexanediethanol, 1,3-cyclohexanediethanol, 1,4-cyclohexanediethanol, tricyclodecanediol, pentacyclopentadecanedimethanol, and 2,6-decahydrodiethanol. Alicyclic dihydroxy compounds such as naphthalenediethanol, 1,5-decahydronaphthalenediethanol, 2,3-decahydronaphthalenediethanol, 2,3-norbornenediethanol, 2,5-norbornenediethanol, and 1,3-adamantanediethanol; 2,2-bis(4-hydroxyphenyl)propane [=bisphenol A], 2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane, 2,2-bis(4-hydroxy-3,5-diethylphenyl)propane, 2 2-bis(4-hydroxy-(3,5-diphenyl)phenyl)propane, 2,2-bis(4-hydroxy-3,5-dibromophenyl)propane, 2,2-bis(4-hydroxyphenyl)pentane, 2,4'-dihydroxy-diphenylmethane, bis(4-hydroxyphenyl)methane, bis(4-hydroxy-5-nitrophenyl)methane, 1,1-bis(4-hydroxyphenyl)ethane, 3,3-bis(4-hydroxyphenyl)pentane, 1,1-bis(4-hydroxyphenyl)propane Aromatic bisphenols include cyclohexane (-hydroxyphenyl), bis(4-hydroxyphenyl) sulfone, 2,4'-dihydroxydiphenyl sulfone, bis(4-hydroxyphenyl) sulfide, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxy-3,3'-dichlorodiphenyl ether, 9,9-bis(4-(2-hydroxyethoxy-2-methyl)phenyl)fluorene, 9,9-bis(4-hydroxyphenyl)fluorene, and 9,9-bis(4-hydroxy-2-methylphenyl)fluorene.

[0194] From the perspective of the lightfastness of polycarbonate resin, it is preferable to use at least one compound that does not have an aromatic ring structure in its molecular structure, namely, a compound selected from the group consisting of aliphatic dihydroxy compounds and alicyclic dihydroxy compounds; as aliphatic dihydroxy compounds, 1,3-propanediol, 1,4-butanediol, and 1,6-hexanediol are particularly preferred; as alicyclic dihydroxy compounds, 1,4-cyclohexanediol and tricyclodecanediol are particularly preferred.

[0195] By using these other dihydroxy compounds, the polycarbonate resin can be improved in terms of flexibility, heat resistance, and moldability. However, if the proportion of structural units derived from other dihydroxy compounds is too high, it will lead to a decrease in mechanical properties and heat resistance. Therefore, the proportion of structural units derived from the dihydroxy compounds of the present invention relative to the total structural units derived from all dihydroxy compounds is 20 mol% or more, preferably 30 mol% or more, and particularly preferably 50 mol% or more.

[0196] Among the dihydroxy compounds and other dihydroxy compounds of the present invention, at least one dihydroxy compound has a boiling point below 300°C at atmospheric pressure, and the dihydroxy compound is easily volatilized during the polymerization reaction, thus greatly enhancing the effect of the present invention; the effect is even greater when the boiling point is below 290°C.

[0197] The dihydroxy compounds of the present invention may contain stabilizers such as reducing agents, antioxidants, deoxidizers, light stabilizers, acid stabilizers, pH stabilizers, and heat stabilizers. Particularly, the dihydroxy compounds of the present invention are prone to deterioration under acidic conditions, therefore, it is preferable to contain basic stabilizers. Examples of basic stabilizers include: long-period periodic tables (Inorganic Chemistry Nomenclature: IUPAC 2005 Recommendations). Hydroxides, carbonates, phosphates, phosphites, phosphates, borates, and fatty acid salts of group 1 or group 2 metals in (2005); basic ammonium compounds such as tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, trimethylethylammonium hydroxide, trimethylbenzylammonium hydroxide, trimethylphenylammonium hydroxide, triethylmethylammonium hydroxide, triethylbenzylammonium hydroxide, triethylphenylammonium hydroxide, triethylbenzylammonium hydroxide, triethylphenylammonium hydroxide, tributylbenzylammonium hydroxide, tributylphenylammonium hydroxide, tetraphenylammonium hydroxide, benzyltriphenylammonium hydroxide, methyltriphenylammonium hydroxide, and butyltriphenylammonium hydroxide; and amine compounds such as 4-aminopyridine, 2-aminopyridine, N,N-dimethyl-4-aminopyridine, 4-diethylaminopyridine, 2-hydroxypyridine, 2-methoxypyridine, 4-methoxypyridine, 2-dimethylaminoimidazolium, 2-methoxyimidazolium, imidazolium, 2-mercaptoimidazolium, 2-methylimidazolium, and aminoquinoline. Among these, from the perspective of their effectiveness and ease of removal by distillation as described later, phosphates or phosphites of Na or K are preferred, with disodium hydrogen phosphate and disodium hydrogen phosphite being the most preferred.

[0198] The content of these alkaline stabilizers in the dihydroxy compounds of the present invention is not particularly limited, but if too little is used, the effect of preventing the deterioration of the dihydroxy compounds of the present invention may not be obtained; if too much is used, the dihydroxy compounds of the present invention may be modified. Therefore, the content is usually 0.0001% to 1% by weight, preferably 0.001% to 0.1% by weight, relative to the dihydroxy compounds of the present invention.

[0199] Furthermore, if the dihydroxy compounds of the present invention containing these alkaline stabilizers are used as raw materials for manufacturing polycarbonate resins, the alkaline stabilizers themselves become polymerization catalysts, making it difficult to control the polymerization rate and quality, and also causing deterioration of the initial color tone, resulting in deterioration of the lightfastness of the molded products. Therefore, before using them as raw materials for manufacturing polycarbonate resins, it is preferable to remove the alkaline stabilizers by means of ion exchange resins or by distillation.

[0200] When the dihydroxy compound of the present invention is a compound with a cyclic ether structure, such as isosorbide, it is prone to slow oxidation upon exposure to oxygen. Therefore, during storage and manufacturing, to prevent oxygen-induced decomposition, it is preferable to process it in an oxygen-free environment, preferably using a deoxidizing agent or under a nitrogen atmosphere. If isosorbide oxidizes, decomposition products such as formic acid may sometimes be produced. Furthermore, isosorbide decomposition products are easily produced in the presence of water; therefore, it is important to avoid moisture contamination during storage. If isosorbide containing, for example, these decomposition products is used as a raw material for manufacturing polycarbonate resin, the resulting polycarbonate resin may become discolored and have significantly deteriorated physical properties. Moreover, it may affect the polymerization reaction, potentially resulting in a failure to obtain a high molecular weight polymer, which is therefore undesirable.

[0201] To obtain the dihydroxy compound of the present invention free from the aforementioned oxidative decomposition products, and to remove the aforementioned basic stabilizer, distillation purification is preferably performed. The distillation in this case can be simple distillation or continuous distillation, without particular limitation. As for the distillation conditions, it is preferable to carry out the distillation under reduced pressure in an inert gas atmosphere such as argon and nitrogen, and to suppress thermal modification, the distillation is carried out at a temperature below 250°C, preferably below 200°C, and particularly preferably below 180°C.

[0202] By employing such distillation purification, the formic acid content in the dihydroxy compound of the present invention is reduced to 20 ppm by weight or less, preferably 10 ppm by weight or less, and particularly preferably 5 ppm by weight or less. Therefore, when the dihydroxy compound containing the above-described dihydroxy compound of the present invention is used as a raw material for manufacturing polycarbonate resin, polycarbonate resin with excellent color tone and thermal stability can be produced without impairing the polymerization reactivity. The formic acid content is determined by ion chromatography.

[0203] (diesterol carbonate)

[0204] The polycarbonate resin of the present invention can be obtained by polycondensation through transesterification using a dihydroxy compound containing the dihydroxy compound of the present invention and a diester as raw materials.

[0205] Examples of the dicarbonates used are typically those represented by the general formula (2) below. These dicarbonates can be used alone or in combination of two or more.

[0206] [Chemistry 21]

[0207]

[0208] (In general formula (2), A) 1 and A 2 Each group is independently an aliphatic group with 1 to 18 carbon atoms, either substituted or unsubstituted, or an aromatic group, either substituted or unsubstituted.

[0209] As the diester represented by the above general formula (2), examples include substituted diphenyl carbonates such as diphenyl carbonate and dibenzyl carbonate; dimethyl carbonate, diethyl carbonate, and di-tert-butyl carbonate, etc., preferably diphenyl carbonate or substituted diphenyl carbonates, and particularly preferably diphenyl carbonate (hereinafter sometimes simply referred to as "DPC"). It should be noted that diesters sometimes contain impurities such as chloride ions, which may inhibit the polymerization reaction or deteriorate the color of the obtained polycarbonate resin, and therefore it is preferable to use them after purification by distillation or the like as needed.

[0210] (Catalyst for transesterification)

[0211] Regarding the polycarbonate resin of the present invention, the polycarbonate resin is manufactured by subjecting a dihydroxy compound containing the dihydroxy compound of the present invention to an ester transesterification reaction with the aforementioned diester. More specifically, the polycarbonate resin is obtained by subjecting the raw materials to esterification and removing byproducts such as monohydroxy compounds from the system. In this case, polycondensation is typically carried out by conducting the esterification reaction in the presence of an esterification reaction catalyst.

[0212] The transesterification catalysts mentioned above (hereinafter sometimes simply referred to as "catalysts" or "polymerization catalysts") have a particular effect on light transmittance and yellow index value at a wavelength of 350 nm.

[0213] As for the catalyst used, there are no limitations on the lightfastness, transparency, hue, heat resistance, thermal stability, and mechanical strength of the manufactured polycarbonate resin, as long as the lightfastness is particularly satisfactory, that is, as long as the light transmittance and yellow index at the aforementioned wavelength of 350 nm are predetermined values. Examples of basic compounds include metal compounds from Group 1 or Group 2 (hereinafter simply referred to as "Group 1" and "Group 2") in the long-period periodic table, basic boron compounds, basic phosphorus compounds, basic ammonium compounds, amine compounds, and other basic compounds. Group 1 metal compounds and / or Group 2 metal compounds are preferred.

[0214] Basic compounds such as basic boron compounds, basic phosphorus compounds, basic ammonium compounds, and amine compounds may also be used in combination with group 1 metal compounds and / or group 2 metal compounds as an adjunct, but it is particularly preferred to use only group 1 metal compounds and / or group 2 metal compounds.

[0215] Furthermore, as a group 1 metal compound and / or a group 2 metal compound, it is usually used in the form of hydroxide or in the form of salt such as carbonate, carboxylate and phenol salt. From the perspective of ease of acquisition and ease of processing, hydroxide, carbonate and acetate are preferred, and from the perspective of color and polymerization activity, acetate is preferred.

[0216] Examples of group 1 metal compounds include: sodium hydroxide, potassium hydroxide, lithium hydroxide, cesium hydroxide, sodium bicarbonate, potassium bicarbonate, lithium bicarbonate, cesium bicarbonate, 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, lithium borohydride, cesium borohydride, sodium phenylboronide. Potassium boron phenylide, lithium boron phenylide, cesium boron phenylide, sodium benzoate, potassium benzoate, lithium benzoate, cesium benzoate, disodium hydrogen phosphate, dipotassium hydrogen phosphate, dilithium hydrogen phosphate, dicesium hydrogen phosphate, disodium phenyl phosphate, dipotassium phenyl hydrogen phosphate, dilithium phenyl phosphate, dicesium phenyl phosphate, sodium, potassium, lithium, cesium alkoxides, phenolic salts, disodium salts, dipotassium salts, dilithium salts, and dicesium salts of bisphenol A, with lithium compounds being preferred.

[0217] Examples of group 2 metal compounds include calcium hydroxide, barium hydroxide, magnesium hydroxide, strontium hydroxide, calcium bicarbonate, barium bicarbonate, magnesium bicarbonate, strontium bicarbonate, calcium carbonate, barium carbonate, magnesium carbonate, strontium carbonate, calcium acetate, barium acetate, magnesium acetate, strontium acetate, calcium stearate, barium stearate, magnesium stearate, and strontium stearate. Among these, magnesium compounds, calcium compounds, and barium compounds are preferred. From the perspective of polymerization activity and the color tone of the obtained polycarbonate resin, at least one metal compound from the group consisting of magnesium compounds and calcium compounds is more preferred, and calcium compounds are most preferred.

[0218] Examples of basic boron compounds include sodium, potassium, lithium, calcium, barium, magnesium, or strontium salts of tetramethylboron, tetraethylboron, tetrapropylboron, tetrabutylboron, trimethylethylboron, trimethylbenzylboron, trimethylphenylboron, triethylmethylboron, triethylbenzylboron, triethylphenylboron, triethylbenzylboron, triethylphenylboron, tributylbenzylboron, tributylphenylboron, tetraphenylboron, benzyltriphenylboron, methyltriphenylboron, butyltriphenylboron, etc.

[0219] Examples of basic phosphorus compounds include triethylphosphine, tri-n-propylphosphine, triisopropylphosphine, tri-n-butylphosphine, triphenylphosphine, tributylphosphine, or quaternary phosphorus salts.

[0220] Examples of basic ammonium compounds include tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, trimethylethylammonium hydroxide, trimethylbenzylammonium hydroxide, trimethylphenylammonium hydroxide, triethylmethylammonium hydroxide, triethylbenzylammonium hydroxide, triethylphenylammonium hydroxide, tributylbenzylammonium hydroxide, tributylphenylammonium hydroxide, tetraphenylammonium hydroxide, benzyltriphenylammonium hydroxide, methyltriphenylammonium hydroxide, and butyltriphenylammonium hydroxide.

[0221] Examples of amine compounds include 4-aminopyridine, 2-aminopyridine, N,N-dimethyl-4-aminopyridine, 4-diethylaminopyridine, 2-hydroxypyridine, 2-methoxypyridine, 4-methoxypyridine, 2-dimethylaminoimidazolium, 2-methoxyimidazolium, imidazole, 2-mercaptoimidazolium, 2-methylimidazolium, and aminoquinoline.

[0222] Generally, the amount of the polymerization catalyst used is preferably 0.1 μmol to 300 μmol, more preferably 0.5 μmol to 100 μmol, relative to all the dihydroxy compounds used in 1 mol of polymerization. When using a compound containing at least one metal selected from the group consisting of lithium and Group 2 of the long-period periodic table, and particularly when using at least one metal compound selected from the group consisting of magnesium compounds and calcium compounds, the amount of the polymerization catalyst, based on the metal content, is generally 0.1 μmol or more, preferably 0.5 μmol or more, and particularly preferably 0.7 μmol or more, relative to 1 mol of all the dihydroxy compounds. Furthermore, as an upper limit, it is generally 20 μmol, preferably 10 μmol, further preferably 3 μmol, particularly preferably 1.5 μmol, and especially suitable to be 1.0 μmol.

[0223] If the amount of catalyst is too small, the polymerization rate may slow down. As a result, if the desired molecular weight of polycarbonate resin is to be obtained, the polymerization temperature must be increased, which deteriorates the color and lightfastness of the resulting polycarbonate resin. Alternatively, unreacted raw materials may volatilize during polymerization, disrupting the molar ratio of the dihydroxy compound (including the dihydroxy compound of this invention) to the aforementioned diester, potentially preventing the achievement of the desired molecular weight. On the other hand, if the amount of polymerization catalyst is too large, it will lead to a deterioration in the color of the resulting polycarbonate resin, and the lightfastness of the polycarbonate resin may also deteriorate.

[0224] In addition, if the polycarbonate resin contains a large amount of sodium, potassium and cesium from Group 1 metals, especially lithium, sodium, potassium and cesium, it may have an adverse effect on the color. These metals may be mixed in not only by the catalyst used, but also by the raw materials or reaction equipment. Therefore, the total amount of these compounds in the polycarbonate resin, in terms of metal content, is generally preferably less than 1 ppm by weight, more preferably less than 1 ppm by weight, and even more preferably less than 0.7 ppm by weight.

[0225] Metals in polycarbonate resin can be recovered through methods such as wet ashing, and the amount of metals in the polycarbonate resin can be determined using methods such as atomic emission luminescence, atomic absorption spectroscopy, and inductively coupled plasma (ICP).

[0226] Furthermore, when using diphenyl carbonate, dibenzyl carbonate, or other substitutes for diphenyl carbonate as the diester represented by general formula (2) to manufacture the polycarbonate resin of the present invention, byproducts phenol and substituted phenols are generated, which inevitably remain in the polycarbonate resin. Since phenol and substituted phenols also have aromatic rings, they absorb ultraviolet light and sometimes become the main cause of deterioration in lightfastness; moreover, they sometimes cause odor during molding. The polycarbonate resin contains more than 1000 ppm by weight of aromatic monohydroxy compounds such as phenol after a typical batch reaction. From the perspective of lightfastness and reducing odor, it is preferable to use a horizontal reactor or an extruder with a vacuum exhaust port that has excellent devolatilization performance, preferably 700 ppm by weight or less, more preferably 500 ppm by weight or less, and particularly preferably 300 ppm by weight or less. Among these, complete removal is difficult in industrial applications, and the lower limit of the content of aromatic monohydroxy compounds is usually 1 ppm by weight.

[0227] It should be noted that, depending on the raw materials used, these aromatic monohydroxy compounds may also have substituents, such as alkyl groups with 5 or fewer carbon atoms.

[0228] Furthermore, when the number of moles of H atoms bonded to the aromatic ring in the polycarbonate resin of the present invention is set as (A), and the number of moles of H atoms bonded to sites other than the aromatic ring is set as (B), the ratio of the number of moles of H atoms bonded to the aromatic ring to the total number of H atoms is expressed as A / (A+B). As described above, since the aromatic ring with ultraviolet absorption capacity may affect the lightfastness, A / (A+B) is preferably 0.1 or less, more preferably 0.05 or less, particularly preferably 0.02 or less, and suitablely 0.01 or less. A / (A+B) can be adjusted by... 1 Quantification was performed using H NMR.

[0229] <Manufacturing Method 1>

[0230] The polycarbonate resin of the present invention is obtained by polycondensation of a dihydroxy compound including the dihydroxy compound of the present invention with the above-mentioned diester via transesterification reaction. Preferably, the dihydroxy compound and the diester are uniformly mixed before the transesterification reaction.

[0231] The mixing temperature is typically above 80°C, preferably above 90°C, and its upper limit is typically below 250°C, preferably below 200°C, and more preferably below 150°C. A temperature between 100°C and 120°C is suitable. If the mixing temperature is too low, the dissolution rate will be slow, and the solubility may be insufficient, which may lead to undesirable conditions such as curing. If the mixing temperature is too high, it may cause thermal degradation of the dihydroxy compounds, resulting in a deterioration of the color of the obtained polycarbonate resin, which may adversely affect its lightfastness.

[0232] The operation of mixing the raw material of the polycarbonate resin of the present invention—including the dihydroxy compound of the present invention—with the above-mentioned diester is preferably carried out in an atmosphere with an oxygen concentration of 10 vol% or less, typically 0.0001 vol% to 10 vol%, wherein, from the viewpoint of preventing color deterioration, it is preferably carried out in an atmosphere of 0.0001 vol% to 5 vol%, particularly 0.0001 vol% to 1 vol%.

[0233] To obtain the polycarbonate resin of the present invention, it is preferred to use it in the following molar ratio: the molar ratio of the above-mentioned carbonate diester is 0.90 to 1.20 relative to the dihydroxy compound including the dihydroxy compound of the present invention used in the reaction, and more preferably 0.95 to 1.10.

[0234] If the molar ratio is small, the terminal hydroxyl groups of the polycarbonate resin produced will increase, the thermal stability of the polymer will deteriorate, and coloring may occur during molding, or the rate of transesterification reaction will be reduced, or the desired high molecular weight polymer may not be obtained.

[0235] Furthermore, if the molar ratio is large, the transesterification reaction rate may decrease, making it difficult to produce polycarbonate with the desired molecular weight. A decreased transesterification reaction rate enhances the thermal history of the polymerization reaction, potentially deteriorating the color tone and lightfastness of the resulting polycarbonate resin.

[0236] Furthermore, if the molar ratio of the aforementioned diester increases relative to the dihydroxy compound including the dihydroxy compound of the present invention, the amount of residual diester in the resulting polycarbonate resin increases, which may absorb ultraviolet light and deteriorate the lightfastness of the polycarbonate resin. The concentration of residual diester in the polycarbonate resin of the present invention is preferably 200 ppm by weight or less, more preferably 100 ppm by weight or less, particularly preferably 60 ppm by weight or less, and suitably 30 ppm by weight or less. In practice, polycarbonate resins sometimes contain unreacted diester, and the lower limit of its concentration is typically 1 ppm by weight.

[0237] In this invention, the method for polycondensing dihydroxy compounds with diesters is typically carried out in multiple stages using two or more reactors in the presence of the aforementioned catalyst. The reaction can be carried out in any of the following forms: batch, continuous, or a combination of batch and continuous. Continuous reactions are preferred for reasons such as ease of setting optimal reaction conditions for each reaction stage and ease of reducing unreacted monomers and reaction byproducts.

[0238] In the early stages of polymerization, it is preferable to obtain the prepolymer under relatively low temperature and low vacuum conditions. In the later stages of polymerization, it is preferable to increase the molecular weight to a predetermined value under relatively high temperature and high vacuum conditions. From the perspective of color tone and lightfastness, it is important to appropriately select the jacket temperature, internal temperature, and pressure within the reaction system for each molecular weight stage. For example, if either the temperature or pressure changes too rapidly before the polymerization reaction reaches the predetermined value, unreacted monomers will distill off, altering the molar ratio of dihydroxy compounds to diesters, which will lead to a decrease in the polymerization rate or prevent the acquisition of polymers with the predetermined molecular weight or terminal groups. As a result, the purpose of this invention may not be achieved.

[0239] Furthermore, to suppress the amount of monomer distilled off, using a reflux cooler in the polymerization reactor is effective, especially in the early stages of polymerization when there is a high proportion of unreacted monomers. The temperature of the refrigerant introduced into the reflux cooler can be appropriately selected based on the monomers used. Generally, the temperature of the refrigerant introduced into the reflux cooler at the inlet is 45°C to 180°C, preferably 80°C to 150°C, and particularly preferably 100°C to 130°C. If the temperature of the refrigerant introduced into the reflux cooler is too high, the reflux flow rate will decrease, and its effectiveness will be reduced; if the temperature is too low, the distillation removal efficiency of the monohydroxy compounds to be distilled off may decrease. Warm water, steam, or hot oil can be used as the refrigerant, with steam or hot oil being preferred.

[0240] In order to properly maintain the polymerization rate, suppress monomer distillation, and avoid compromising the color, thermal stability, and lightfastness of the final polycarbonate resin, the selection of the type and amount of the catalyst is very important.

[0241] The polycarbonate resin of the present invention is preferably manufactured using a catalyst and through multi-stage polymerization in two or more reactors. The reasons for using two or more reactors for polymerization are as follows: In the initial stage of the polymerization reaction, the reaction solution contains a large amount of monomer, making it important to suppress monomer volatilization while maintaining the necessary polymerization rate; in the later stage of the polymerization reaction, in order to shift the equilibrium towards polymerization, it is important to thoroughly distill away the byproduct monohydroxy compounds. Therefore, from the perspective of production efficiency, it is preferable to use two or more polymerization reactors arranged in series to set different polymerization reaction conditions.

[0242] As described above, at least two reactors are sufficient for the method of this invention, but from the perspective of production efficiency, three or more are preferred, three to five are particularly preferred, and four are especially preferred.

[0243] In this invention, if there are two or more reactors, the reactors can further have multiple reaction stages with different conditions, and the temperature and pressure can be continuously changed, etc.

[0244] In this invention, the polymerization catalyst can be added to the raw material preparation tank or the raw material storage tank, or it can be added directly to the polymerization tank. From the perspective of supply stability and polymerization control, a catalyst supply pipeline is set up along the raw material pipeline before it is supplied to the polymerization tank, preferably in the form of an aqueous solution.

[0245] If the polymerization temperature is too low, it will lead to a decrease in productivity and a reduced thermal history of the product; if the temperature is too high, it will not only cause the monomer to volatilize, but may also promote the decomposition and coloring of polycarbonate resin.

[0246] Specifically, regarding the first stage reaction, the reaction is carried out at a temperature of 140°C to 270°C, preferably 180°C to 240°C, more preferably 200°C to 230°C, and at a pressure of 110 kPa to 1 kPa, preferably 70 kPa to 5 kPa, more preferably 30 kPa to 10 kPa (absolute pressure), for 0.1 hours to 10 hours, preferably 0.5 hours to 3 hours, while the generated monohydroxy compound is distilled off the reaction system.

[0247] After the second stage, the pressure of the reaction system is slowly reduced from the pressure of the first stage. Then, while removing the generated monohydroxy compound from the reaction system, the final pressure (absolute pressure) of the reaction system is reduced to below 200 Pa. The reaction is carried out for 0.1 to 10 hours, preferably 1 to 6 hours, and particularly preferably 0.5 to 3 hours, at an internal temperature of 210°C to 270°C, preferably 220°C to 250°C.

[0248] In particular, to suppress coloration and thermal degradation of the polycarbonate resin and obtain a polycarbonate resin with good color tone and lightfastness, the maximum internal temperature throughout the entire reaction stage is preferably less than 250°C, and particularly preferably 225°C to 245°C. Furthermore, to suppress the decrease in polymerization rate in the latter half of the polymerization reaction and minimize degradation caused by thermal history, a horizontal reactor with excellent plugging flow and interfacial renewal properties is preferably used in the final stage of polymerization.

[0249] In order to obtain polycarbonate resin with a specific molecular weight, excessively increasing the polymerization temperature or extending the polymerization time will tend to reduce the ultraviolet transmittance and increase the YI value.

[0250] From the perspective of efficient resource utilization, monohydroxy compounds, as byproducts, are preferably refined as needed and reused as raw materials for diphenyl carbonate or bisphenol A, etc.

[0251] <Second Manufacturing Method>

[0252] The second method for manufacturing polycarbonate resin in this invention is a method for manufacturing polycarbonate resin by using a catalyst, diester as a raw material monomer, and a dihydroxy compound, and by using two or more reactors to polycondense the raw material monomer through a multi-stage transesterification reaction, characterized in that:

[0253] The dihydroxy compound includes at least a dihydroxy compound having a portion of the structure shown in the following general formula (1);

[0254] At least one of the reactors that distills the monohydroxy compound, a byproduct of transesterification, at a rate of 20% or more of the theoretical distillate is a reactor having an internal volume of 20 L or more and equipped with a heating unit and a reflux cooler. The heating unit is used to heat the reactor using a heating medium, the temperature of which differs from the temperature of the reaction liquid in the reactor by at least 5 °C.

[0255] The total amount of monomer distilled off during the entire reaction process is less than 10% by weight relative to the total amount of raw monomer.

[0256] [Chemistry 22]

[0257]

[0258] (This excludes cases where the part shown in the above general formula (1) is part of -CH2-OH.)

[0259] In the second manufacturing method, at least one of the reactors from which the monohydroxy compound is distilled at a rate of 20% or more of its theoretical distillate has an internal volume of 20 L or more, preferably 30 L or more. The larger the internal volume of the reactor, the greater the effect of the present invention.

[0260] In the second manufacturing method of the present invention, a dicarbonate and a dihydroxy compound are subjected to polycondensation (sometimes simply referred to as polymerization) through a multi-stage transesterification reaction in two or more reactors in the presence of the aforementioned catalyst. During this polymerization reaction, a monohydroxy compound (for example, phenol if diphenyl carbonate is used as the dicarbonate) is produced as a byproduct. Therefore, polymerization is carried out while the byproduct monohydroxy compound is distilled off the system. In the initial stage of polymerization, the amount of byproduct monohydroxy compound generated per unit time is large, which will capture a large amount of latent heat of vaporization. Therefore, in the present invention, at least one of the reactors in which the monohydroxy compound is distilled off at a rate of 20% or more of its theoretical distillate is a reactor equipped with a heating unit. This heating unit is used to heat the reactor using a heating medium, such that the temperature of the introduced heating medium is higher than the temperature of the reaction liquid in the reactor (hereinafter sometimes referred to as "internal temperature"), that is, the temperature difference is at least 5°C (heating medium temperature > internal temperature).

[0261] Here, in this invention, the theoretical distillation yield of the monohydroxy compound is defined as twice the molar number of the diester used as a feedstock. The term "reactor that distills at a yield of 20% or more of the theoretical distillation yield" refers to a reactor in the case of a batch reaction where the total amount of monohydroxy compound distilled from one reactor is 20% or more of the theoretical distillation yield calculated from the amount of diester initially added as a feedstock; and in the case of a continuous reaction, where the amount of monohydroxy compound distilled from one reactor per unit time is 20% or more of the theoretical distillation yield calculated from the amount of diester supplied as a feedstock per unit time.

[0262] Furthermore, examples of heating units for heating a reactor using a heating medium include jacketed units (hereinafter simply referred to as heating medium jackets) located around (entirely or partially) the reactor, units with internal coils installed inside the reactor, and units with heat exchangers located outside the reactor. A heating medium jacket is preferred. When using a heating medium jacket, it is effective to prevent the temperature of the heating medium within the jacket from becoming excessively high by also installing internal coils inside the reactor, supplying heat from within the reactor, and increasing the heat transfer area.

[0263] If the temperature difference between the heating medium and the reaction liquid is less than 5°C, the heat balance of the reactor will deteriorate, and the temperature of the reaction liquid may not reach the predetermined temperature. In particular, if the size of the reactor increases, for example, if the heating unit is a heating medium jacket, the heat transfer area of ​​the heating medium jacket tends to decrease relative to the internal volume of the reactor. Therefore, it is preferable that the temperature difference between the heating medium and the reaction liquid is large, preferably 10°C or more, and particularly preferably 15°C or more.

[0264] Conversely, if the temperature difference between the heating medium and the reaction liquid is too large, not only will the amount of raw material monomers distilled increase, but the thermal degradation of the contents will also be more severe. Therefore, it is preferable to use temperatures below 80°C, more preferably below 40°C, and particularly preferably below 30°C.

[0265] The temperature of the heating medium introduced can be appropriately determined according to the desired reaction liquid temperature. If the temperature of the heating medium is too high, the amount of raw material monomers distilled will be too much. Therefore, the maximum temperature is preferably below 265°C, more preferably below 260°C, and particularly preferably below 255°C.

[0266] Regarding maintaining the temperature of the heating medium at least 5°C higher than the temperature of the reaction liquid, ensuring this temperature remains at least 5°C higher throughout the entire reaction in the reactor, temperature control can also be implemented only during the time or period when the monohydroxy compound distills significantly. Generally, the former is chosen for continuous reactions, while the latter is chosen for batch reactions.

[0267] It should be noted that, in this invention, the temperature of the heating medium refers to its temperature before it is introduced into the heating unit. For example, if the heating unit is a heating medium jacket, it refers to the temperature of the heating medium before it is introduced into the heating medium jacket located around (all or part of) the reactor. Furthermore, in this invention, the temperature of the reaction liquid refers to the temperature of the reaction liquid measured using a thermocouple or similar measuring instrument.

[0268] In this invention, for reactors in which monohydroxy compounds generated as byproducts of polymerization are distilled out at a rate of 20% or more of the theoretical distillate, the internal temperature of at least one reactor is preferably 140–270°C, more preferably 180–240°C, and even more preferably 200–230°C. If the internal temperature is too high, not only will the distillate yield of the raw material monomer increase, but thermal degradation will also become more severe; if it is too low, the reaction rate will decrease and the production efficiency will decrease.

[0269] In this invention, in order to suppress the amount of monomer distilled out, at least one of the reactors in which the monohydroxy compound is distilled out at a rate of 20% or more of its theoretical distillate is provided with a reflux cooler.

[0270] The temperature of the refrigerant introduced into the reflux cooler is preferably 45°C to 180°C, more preferably 80°C to 150°C, and particularly preferably 100°C to 130°C at the inlet of the reflux cooler. If the refrigerant temperature is too high, the reflux flow rate will decrease, and its effectiveness may be reduced; conversely, if the temperature is too low, the distillation removal efficiency of the monohydroxy compounds that are to be distilled off may be reduced. Warm water, steam, or hot oil are used as the refrigerant, with steam or hot oil being preferred.

[0271] To suppress the amount of monomer distilled, it is preferable that the reactor in which monohydroxy compounds are distilled out in an amount of more than 10% of their theoretical distillate is also equipped with a reflux cooler.

[0272] In the second manufacturing method of the present invention, it is important that the total amount of monomer distilled out in all reaction stages is less than 10% by weight relative to the total amount of raw material monomers.

[0273] The total amount of monomers distilled during the entire reaction process (hereinafter sometimes referred to as "the amount of monomers distilled") refers to the total amount of all monomers distilled from the start to the end of the transesterification reaction.

[0274] When the amount of distilled monomer exceeds 10% by weight relative to the total amount of raw material monomers, it will not only lead to the deterioration of the raw material units, but also have the problem of making it difficult to control the concentration of terminal groups that affect the quality at the predetermined value; when using more than two dihydroxy compounds, the molar ratio of the dihydroxy compounds used changes during polymerization, and the desired molecular weight and composition of polycarbonate resin may not be obtained.

[0275] The amount of monomer distilled is preferably 5% by weight or less, more preferably 3% by weight or less, and particularly preferably 2% by weight or less relative to the total amount of raw monomer.

[0276] If the amount of monomer distilled is small, the improvement of the raw material unit is significant. In addition, it is necessary to make the internal temperature or heating medium temperature too low, the pressure too high, increase the amount of catalyst, or extend the polymerization time. This reduces the production efficiency of polycarbonate resin and causes the quality to deteriorate. Therefore, its lower limit is usually 0.2% by weight, preferably 0.4% by weight, and more preferably 0.6% by weight.

[0277] The amount of monomer distilled as specified in this invention can be achieved, as described above, by appropriately selecting the type and amount of catalyst, the temperature of the reaction solution, the temperature of the heating medium, the reaction pressure, the residence time, and the reflux conditions.

[0278] For example, in the early stages of polymerization, prepolymers are obtained under relatively low temperatures and low vacuum; in the later stages of polymerization, the molecular weight is increased to the predetermined value under relatively high temperatures and high vacuum. Appropriate selection of the heating medium temperature, internal temperature, and pressure within the reaction system is crucial for each molecular weight stage. For instance, if either temperature or pressure changes too rapidly before the polymerization reaction reaches the predetermined value, unreacted monomers will distill off, altering the molar ratio of dihydroxy compounds to diesters, potentially leading to a decrease in polymerization rate or the inability to obtain polymers with the predetermined molecular weight or terminal groups.

[0279] In order to maintain a stable polymerization rate, suppress monomer distillation, and avoid compromising the color, thermal stability, and lightfastness of the final polycarbonate resin, the selection of the type and amount of catalyst mentioned above is also very important.

[0280] In the second manufacturing method of the present invention, the polycarbonate resin is manufactured by multi-stage polymerization of raw materials using a catalyst and employing two or more reactors. The reason for using two or more reactors for polymerization is as follows: In the initial stage of the polymerization reaction, the reaction solution contains a large amount of monomer, so it is important to suppress monomer volatilization while maintaining the necessary polymerization rate; in the later stage of the polymerization reaction, in order to shift the equilibrium towards the polymerization side, it is important to thoroughly distill away the byproduct monohydroxy compounds. Therefore, from the perspective of production efficiency, it is preferable to use two or more polymerization reactors arranged in series to set different polymerization reaction conditions, and as a reaction method, a continuous operation is preferred.

[0281] As described above, the method of the present invention uses at least two reactors, and from the perspective of production efficiency, three or more reactors are preferred, three to five reactors are preferred, and four reactors are particularly preferred.

[0282] In this invention, if there are two or more reactors, the reactors can further have multiple reaction stages with different conditions to change the temperature and pressure in stages or continuously.

[0283] That is, for example, including the following situations: using two reactors and changing the reaction conditions of each reactor to make it a two-stage polymerization; and using two reactors, having two reaction stages with different conditions in the first reactor and one reaction condition in the second reactor to make it a three-stage polymerization, etc.

[0284] In this invention, the catalyst can be added to the raw material preparation tank, the raw material storage tank, or directly to the reactor. From the perspective of supply stability and polymerization control, a catalyst supply pipeline is set up along the raw material pipeline before it is supplied to the reactor, preferably using an aqueous solution for supply.

[0285] If the temperature of the transesterification reaction is too low, it will lead to a decrease in productivity and an increase in the thermal history of the product; if it is too high, it will not only cause the volatilization of monomers, but may also promote the decomposition and coloring of polycarbonate resin.

[0286] Regarding the internal temperature of at least one reactor in which the byproduct monohydroxy compound is distilled out at a rate of 20% or more of the theoretical distillate, as described above, the maximum temperature is 140°C to 270°C, preferably 180°C to 240°C, and more preferably 200°C to 230°C. Other conditions include a pressure typically between 110 kPa and 1 kPa, preferably between 70 kPa and 5 kPa, and more preferably between 30 kPa and 10 kPa (absolute pressure), and a reaction typically lasting 0.1 to 10 hours, preferably 0.5 to 3 hours. Under these reaction conditions, the transesterification reaction is carried out while the generated monohydroxy compound is distilled away from the reaction system.

[0287] In the second stage and thereafter, the pressure of the reaction system is slowly reduced from the pressure in the first stage. Then, while removing the generated monohydroxy compound from the reaction system, the final pressure (absolute pressure) of the reaction system is typically below 1000 Pa, preferably below 200 Pa. The second stage and thereafter are carried out at a maximum internal temperature of 210°C to 270°C, preferably 220°C to 250°C.

[0288] In particular, to suppress coloration and thermal degradation of the polycarbonate resin and to ensure that the amount of distilled monomer is less than 10% by weight relative to the total amount of raw material monomers, the highest internal temperature during the entire reaction stage is preferably less than 250°C, and particularly preferably 225°C to 245°C. In the method of the present invention, from the perspective of efficient resource utilization, the monohydroxy compound, as a byproduct, is preferably purified as needed and reused as a raw material for diesters or bisphenol compounds, etc.

[0289] <Third Manufacturing Method>

[0290] The third method for manufacturing polycarbonate resin in this invention is a method for manufacturing polycarbonate resin by using a catalyst, diester as a raw material monomer, and a dihydroxy compound, and by using two or more reactors to polycondense the raw material monomer through a multi-stage transesterification reaction, characterized in that:

[0291] The dihydroxy compound includes two or more dihydroxy compounds, at least one of which is a dihydroxy compound having the part of the structure shown in the following general formula (1);

[0292] At least one of the reactors that distills the monohydroxy compound, a byproduct of transesterification, at a rate of 20% or more of the theoretical distillate is a reactor having an internal volume of 20 L or more and equipped with a heating unit and a reflux cooler. The heating unit is used to heat the reactor using a heating medium, the temperature of which differs from the temperature of the reaction liquid in the reactor by at least 5 °C.

[0293] The absolute value of the difference between the molar percentage of the dihydroxy compound fed into the reactor as raw material and the molar percentage of the dihydroxy compound structural units in the resulting polycarbonate resin, divided by the molar percentage of the dihydroxy compound fed into the reactor as raw material, is less than 0.03 for at least one dihydroxy compound and not greater than 0.05 for any single dihydroxy compound.

[0294] [Chemistry 23]

[0295]

[0296] (This excludes cases where the part shown in the above general formula (1) is part of -CH2-OH.)

[0297] To provide a more specific explanation, the reactor, heating unit, reflux cooler, and temperature conditions of each piece of equipment are as described in the second manufacturing method above. However, in the third manufacturing method, two or more dihydroxy compounds are used as raw materials. When the various dihydroxy compounds are fed into the reactor as raw materials, the molar percentages of each compound are set as A, B, C…N mol%, and the molar percentages of the structural units derived from each dihydroxy compound in the obtained polycarbonate resin are set as a, b, c…n mol%, respectively. Therefore, (|(aA) / A|, |(bB) / B|, |(cC)…) The value of any one of / C|, ..., |(nN / N|) is 0.03 or less, preferably 0.02 or less, more preferably 0.01 or less, and particularly preferably 0.005 or less. Furthermore, it is necessary that the value is not greater than 0.05 for any dihydroxy compound, preferably 0.03 or less, more preferably 0.02 or less, particularly preferably 0.01 or less, and especially preferably 0.005 or less. This value, as described above, can be achieved by appropriately selecting the type and amount of catalyst, the temperature (internal temperature) of the transesterification reaction, the temperature and pressure of the heating medium, the residence time, and the reflux conditions.

[0298] (Dihydroxy compound)

[0299] In the second and third manufacturing methods of the present invention, the dihydroxy compound used as the raw material monomer may appropriately be the dihydroxy compound described above.

[0300] (diesterol carbonate)

[0301] In the second and third manufacturing methods of the present invention, the diester used as the raw material monomer may appropriately be the diester described above.

[0302] In the second and third manufacturing methods of the present invention, the dihydroxy compound and the diester used as raw materials are preferably mixed uniformly before the transesterification reaction.

[0303] The mixing temperature is typically above 80°C, preferably above 90°C, and its upper limit is typically below 250°C, preferably below 200°C, and more preferably below 150°C. A temperature between 100°C and 120°C is suitable. If the mixing temperature is too low, the dissolution rate will be slow, and the solubility may be insufficient, often leading to undesirable conditions such as curing. If the mixing temperature is too high, it may cause thermal degradation of the dihydroxy compounds, resulting in a deterioration of the color of the obtained polycarbonate resin, which may adversely affect its lightfastness and heat resistance.

[0304] In the second and third manufacturing methods of the present invention, the operation of mixing the dihydroxy compound, which includes the dihydroxy compound of the present invention, as a raw material with the diester is generally preferably carried out in an atmosphere with an oxygen concentration of 10 vol% or less. From the viewpoint of preventing color deterioration, it is further preferred to carry out the operation in an atmosphere of 0.0001 vol% to 10 vol%, wherein it is 0.0001 vol% to 5 vol%, and particularly 0.0001 vol% to 1 vol%.

[0305] In this invention, the diester is typically used in a molar ratio of 0.90 to 1.20 relative to all the dihydroxy compounds containing the dihydroxy compounds of this invention used in the reaction. This molar ratio is preferably 0.95 to 1.10, more preferably 0.97 to 1.03, and particularly preferably 0.99 to 1.02. A molar ratio that is too high or too low will reduce the rate of the transesterification reaction, increase the thermal history of the polymerization reaction, and potentially worsen the color of the resulting polycarbonate resin, and may even prevent the acquisition of the desired high molecular weight polymer.

[0306] (Transesterification catalyst)

[0307] In the second and third manufacturing methods of the present invention, when polycarbonate resin is manufactured by polycondensation of a dihydroxy compound including the dihydroxy compound of the present invention with a diester via a transesterification reaction as described above, a transesterification catalyst is present. That is, a specific compound is present in the first reactor in which a monohydroxy compound generated as a byproduct of the polymerization reaction is distilled off at a rate of 20% or more of the theoretical distillate.

[0308] In the method of the present invention, the transesterification catalyst (polymerization catalyst) has a particular effect on the light transmittance at a wavelength of 350 nm and the yellow index (YI) value.

[0309] The transesterification catalyst described above can be used as the transesterification catalyst.

[0310] Typically, the amount of the catalyst used is preferably 0.1 μmol to 300 μmol, more preferably 0.5 μmol to 100 μmol, relative to all the dihydroxy compounds used. When using a compound containing at least one metal selected from lithium and Group 2 metals of the long-period periodic table, the amount of the catalyst, in terms of metal content, is typically 0.1 μmol or more, preferably 0.5 μmol or more, and particularly preferably 0.7 μmol or more per 1 mol of all the dihydroxy compounds used. Furthermore, as an upper limit, it is typically 20 μmol, preferably 10 μmol, further preferably 3 μmol, particularly preferably 1.5 μmol, and especially preferably 1.0 μmol.

[0311] It should be noted that the above catalyst can be added directly to the reactor, or the following method can be adopted: the dihydroxy compound is premixed with the diester and added to the feed conditioning tank, and then the catalyst is present in the reactor.

[0312] If the amount of catalyst is too small, sufficient polymerization activity will not be obtained, the polymerization reaction will proceed slowly, and it will be difficult to obtain polycarbonate resin with the desired molecular weight. In addition, the amount of raw material monomers entering the polycarbonate resin will decrease, and the amount of monomers distilled off with the by-product monohydroxy compounds will increase. As a result, the raw material units may decrease and their recovery may require additional energy. Furthermore, when copolymerizing with two or more dihydroxy compounds, the composition ratio of the monomers used as raw materials as described above will change with the ratio of structural units derived from each monomer unit in the finished polycarbonate resin.

[0313] On the other hand, if too much catalyst is used, the problem of excessive amount of distilled monomer tends to be improved; however, the color, lightfastness, and thermal stability of the resulting polycarbonate resin may deteriorate.

[0314] In addition, if polycarbonate resin contains a large amount of Group 1 metals, especially sodium, potassium and cesium, and particularly lithium, sodium, potassium and cesium, it may have an adverse effect on the color. These metals may be introduced not only from the catalyst used, but also from the raw materials or reaction equipment. Therefore, the total amount of these compounds in polycarbonate resin, in terms of metal content, is usually less than 1 ppm by weight, preferably less than 0.8 ppm by weight, and more preferably less than 0.7 ppm by weight.

[0315] Metals in polycarbonate resin can be recovered through methods such as wet ashing, and the amount of metals in the polycarbonate resin can be determined using methods such as atomic emission luminescence, atomic absorption spectroscopy, and inductively coupled plasma (ICP).

[0316] In this invention, by suppressing the volatilization of monomers in the polymerization reaction, the molar ratio of the dihydroxy compound used as a raw material to the diester carbonate can be kept close to the theoretical amount of 1.00, and a high molecular weight polycarbonate resin with good color can be obtained without reducing the polymerization rate.

[0317] (The obtained polycarbonate resin)

[0318] For the polycarbonate resin obtained in the second and third manufacturing methods of the present invention, the light transmittance of the molded body (thickness 3 mm) formed from the resin at a wavelength of 350 nm is preferably 60% or more, more preferably 65% ​​or more, and particularly preferably 70% or more. If the light transmittance at this wavelength is less than 60%, the absorption increases and the light resistance may deteriorate.

[0319] Furthermore, the polycarbonate resin obtained in the second and third manufacturing methods of the present invention has a light transmittance of 30% or more, more preferably 40% or more, and particularly preferably 50% or more at a wavelength of 320 nm for the molded body (a flat plate with a thickness of 3 mm) formed from the resin. If the light transmittance at this wavelength is less than 30%, the lightfastness tends to deteriorate.

[0320] For the polycarbonate resins obtained in the second and third manufacturing methods of the present invention, an irradiance of 1.5 kW / m² at a wavelength of 300 nm to 400 nm is applied using a metal halide lamp at an environment of 63°C and 50% relative humidity. 2 After the molded body (3 mm thick) formed from the resin is subjected to irradiation treatment for 100 hours, the yellow index (YI) value based on ASTM D1925-70, measured by transmitted light, is preferably 12 or less, more preferably 10 or less, and particularly preferably 8 or less.

[0321] Furthermore, regarding the polycarbonate resin obtained in the second and third manufacturing methods of the present invention, when the resin is molded into a plate with a thickness of 3 mm, and the plate is not subjected to the metal halide lamp irradiation treatment as described above, the yellow index value (i.e., the initial yellow index value, referred to as the initial YI value) measured by transmitted light is generally preferably 10 or less, more preferably 7 or less, and particularly preferably 5 or less. Moreover, the absolute value of the difference between the yellow index before and after metal halide lamp irradiation is preferably 6 or less, more preferably 4 or less, and particularly preferably 3 or less.

[0322] If the initial yellow index (YI) value is greater than 10, the lightfastness tends to deteriorate. In addition, if the absolute value of the difference between the yellow index (YI) values ​​before and after metal halide lamp irradiation is greater than 6, the resin will become discolored under prolonged exposure to sunlight, artificial lighting, etc., and may not be usable in applications where transparency is particularly required.

[0323] Furthermore, for the polycarbonate resin obtained in the second and third manufacturing methods of the present invention, when the resin is molded into a plate with a thickness of 3 mm, the L* value specified by the International Commission on Illumination (CIE) and measured using transmitted light is generally preferably 96.3 or higher, more preferably 96.6 or higher, and particularly preferably 96.8 or higher. When the L* value is lower than 96.3, the lightfastness tends to deteriorate.

[0324] To obtain such a polycarbonate resin, in addition to the features of the present invention, as described above, it is manufactured by, for example, limiting the specific metal concentration during polymerization, appropriately selecting the type and amount of catalyst, appropriately selecting the temperature and time during polymerization, reducing compounds that cause coloring (e.g., residual monomers, residual phenols, residual diphenyl carbonate), and reducing impurities that contribute to the coloring of the raw material monomers used. In particular, the type and amount of catalyst, and the temperature and time during polymerization are important.

[0325] The molecular weight of the polycarbonate resin obtained in the manufacturing method of the present invention can be expressed as specific viscosity. The specific viscosity is usually 0.30 dL / g or more, preferably 0.35 dL / g or more, and the upper limit of the specific viscosity is preferably 1.20 dL / g or less, more preferably 1.00 dL / g or less, and even more preferably 0.80 dL / g or less.

[0326] If the specific viscosity of polycarbonate resin is too low, the mechanical strength of the molded product may decrease; if it is too high, the fluidity during molding tends to decrease, resulting in reduced productivity or moldability.

[0327] It should be noted that the specific viscosity was determined as follows: using dichloromethane as a solvent, the polycarbonate concentration was precisely adjusted to 0.6 g / dL, and the measurement was performed using an Ubbelohde viscometer at a temperature of 20.0℃±0.1℃.

[0328] Furthermore, the lower limit of the concentration of the terminal group shown in the following structural formula (3) in the polycarbonate resin obtained by the manufacturing method of the present invention is generally preferably 20 μeq / g, more preferably 40 μeq / g, particularly preferably 50 μeq / g, and the upper limit is generally preferably 160 μeq / g, more preferably 140 μeq / g, particularly preferably 100 μeq / g.

[0329] If the concentration of the terminal group shown in the following structural formula (3) is too high, even if the resin has a good color tone immediately after polymerization or during molding, it may cause the color tone to deteriorate after exposure to ultraviolet light; conversely, if the concentration is too low, the thermal stability may be reduced.

[0330] In order to control the concentration of the terminal group shown in the following structural formula (3), the molar ratio of the dihydroxy compound, including the dihydroxy compound of the present invention, to the diester as raw material can be controlled. In addition, methods such as controlling the polymerization pressure and polymerization temperature, and the temperature of the reflux cooler during the transesterification reaction based on the ease of monomer volatilization can also be cited. According to the present invention, since the volatilization of monomer can be suppressed, the molar ratio of raw materials can be easily controlled.

[0331] [Chemistry 24]

[0332]

[0333] The polycarbonate resin obtained in the manufacturing method of the present invention is typically cooled and cured after polycondensation as described above, and then granulated using a rotary cutter or the like.

[0334] There are no limitations on the granulation method. Examples include: discharging the resin from the final polymerization reactor in a molten state, cooling and solidifying it in the form of a filament, and then granulating it; feeding the resin from the final polymerization reactor in a molten state into a single-screw or twin-screw extruder, melting and extruding it, and then cooling and solidifying it to granulate it; or discharging the resin from the final polymerization reactor in a molten state, cooling and solidifying it in the form of a filament for temporary granulation, and then feeding the resin back into a single-screw or twin-screw extruder, melting and extruding it, and then cooling and solidifying it to granulate it; and so on.

[0335] At this point, residual monomers can be depressurized and devolatilized in the extruder, and commonly known heat stabilizers, neutralizers, ultraviolet absorbers, mold release agents, colorants, antistatic agents, slip agents, lubricants, plasticizers, compatibilizers, flame retardants, etc., can be added or mixed.

[0336] The melt mixing temperature in the extruder depends on the glass transition temperature and molecular weight of the polycarbonate resin, and is typically 150°C to 300°C, preferably 200°C to 270°C, and more preferably 230°C to 260°C. If the melt mixing temperature is below 150°C, the melt viscosity of the polycarbonate resin is high, the load on the extruder increases, and the productivity decreases. If the temperature is above 300°C, the thermal degradation of the polycarbonate becomes severe, resulting in a decrease in mechanical strength due to the reduction in molecular weight, discoloration, and gas generation.

[0337] In the method for manufacturing the polycarbonate resin of the present invention, a filter is preferably provided to prevent the contamination of foreign matter. The filter is preferably located downstream of the extruder, and to achieve a filtration accuracy of 99%, the foreign matter removal size (mesh size) of the filter is preferably 100 μm or less. In particular, where the contamination of minute foreign matter is undesirable in membrane applications, it is preferably 40 μm or less, and more preferably 10 μm or less.

[0338] In addition, regarding the extrusion of polycarbonate resin, in order to prevent foreign matter from being mixed in after extrusion, it is preferable to carry out the process in a cleanroom with a high cleanliness level higher than level 7 as defined in JIS B9920 (2002), and even more preferably in a cleanroom with a cleanliness level higher than level 6.

[0339] Furthermore, when cooling and chipping the extruded polycarbonate resin, cooling methods such as air cooling and water cooling are preferred. For air cooling, air that has been pre-filtered with a HEPA filter or similar device to remove impurities is preferred to prevent re-adhesion of airborne impurities. When using water cooling, water that has been treated with an ion exchange resin or similar device to remove metal components and further filtered to remove impurities is preferred. The filter used should have a mesh size of 10 μm to 0.45 μm, with a filtration accuracy of 99% removal.

[0340] The polycarbonate resin obtained in the manufacturing method of the present invention can be molded into molded articles using commonly known methods such as injection molding, extrusion molding, and compression molding.

[0341] In addition, before various molding processes, additives such as heat stabilizers, neutralizers, UV absorbers, release agents, colorants, antistatic agents, slip agents, lubricants, plasticizers, compatibilizers, and flame retardants can be mixed into polycarbonate resin using a drum mixer, super mixer, floating mixer, V-type mixer, NAUTA MIXER, Banbury mixer, extruder, etc.

[0342] The polycarbonate resin obtained in the manufacturing method of the present invention can also be mixed with one or more of the following: aromatic polycarbonate, aromatic polyester, aliphatic polyester, polyamide, polystyrene, polyolefin, acrylic resin, amorphous polyolefin, synthetic resin such as ABS and AS, biodegradable resin such as polylactic acid and polybutylene succinate, and rubber, and used in the form of a polymer alloy.

[0343] This invention can provide polycarbonate resins with excellent lightfastness, transparency, hue, heat resistance, thermal stability, and mechanical strength. In addition, it can reduce monomer loss and effectively manufacture these stable polycarbonate resins.

[0344] Example

[0345] The present invention will be described in more detail below through embodiments, but the present invention is not limited to the following embodiments as long as it does not go beyond its essential points.

[0346] <Examples 1-3>

[0347] The following methods are used to evaluate the physical properties or characteristics of polycarbonate.

[0348] (1) Determination of oxygen concentration

[0349] The oxygen concentration inside the polymerization reactor was measured using an oxygen analyzer (manufactured by AMI Corporation: 1000RS).

[0350] (2) Determination of specific viscosity

[0351] A polycarbonate resin sample was dissolved using dichloromethane as a solvent to prepare a polycarbonate solution with a concentration of 0.6 g / dL. The viscosity was measured using an Ubbelohde viscometer manufactured by Moritomo Rika Kogyo Co., Ltd. at a temperature of 20.0℃ ± 0.1℃. The relative viscosity ηrel was calculated from the solvent outflow time t0 and the solution outflow time t using the following formula.

[0352] ηrel=t / t0

[0353] The specific viscosity ηsp is obtained from the relative viscosity using the following formula.

[0354] ηsp=(η-η0) / η0=ηrel-1

[0355] Divide the specific viscosity by the concentration c (g / dL) to obtain the specific viscosity ηsp / c. The higher this value, the larger the molecular weight.

[0356] (3) Determination of the ratio of structural units derived from each dihydroxy compound and the concentration of terminal phenyl groups in polycarbonate resin

[0357] The structural units derived from various dihydroxy compounds in polycarbonate resin were determined as follows: 30 mg of polycarbonate resin was weighed and dissolved in approximately 0.7 mL of deuterated chloroform to prepare a solution. This solution was then added to an NMR tube with an inner diameter of 5 mm and subjected to NMR at room temperature using a JNM-AL400 (resonance frequency 400 MHz) manufactured by JEOL Ltd. 1 ¹H NMR spectroscopy was performed. The ratio of structural units originating from each dihydroxy compound was determined by the ratio of signal intensities attributable to each structural unit. For the concentration of the terminal phenyl group, 1,1,2,2-tetrabromoethane was used as an internal standard, and the procedure was performed in the same manner as described above. 1 The concentration of terminal phenyl groups was determined by ¹H NMR analysis, based on the ratio of signal intensities attributed to the internal standard and those attributed to the terminal phenyl groups.

[0358] (4) Determination of metal concentration in polycarbonate resin

[0359] Approximately 0.5 g of polycarbonate resin particles were accurately weighed into a microwave decomposition vessel manufactured by Perkin Elmer. 2 mL of 97% sulfuric acid was added, and the mixture was microwaved at 230°C for 10 minutes under a sealed environment. After cooling to room temperature, 1.5 mL of 68% nitric acid was added, and the mixture was microwaved at 150°C for 10 minutes under a sealed environment. The mixture was then cooled to room temperature again, and 2.5 mL of 68% nitric acid was added. The mixture was then microwaved again at 230°C for 10 minutes under a sealed environment to ensure complete decomposition of the contents. After cooling to room temperature, the resulting liquid was diluted with pure water, and the metal concentration was determined using an ICP-MS manufactured by ThermoQuest.

[0360] (5) Determination of phenol and DPC concentrations in polycarbonate resin

[0361] 1.25 g of polycarbonate resin sample was dissolved in 7 mL of dichloromethane to prepare a solution. Acetone was then added to bring the total volume to 25 mL for reprecipitation. The treated solution was then filtered through a 0.2 μm rotating disc filter and quantified using liquid chromatography.

[0362] (6) Evaluation method of initial color tone of polycarbonate resin

[0363] Polycarbonate resin granules were dried at 110°C for 10 hours under a nitrogen atmosphere. Next, the dried polycarbonate resin granules were fed into an injection molding machine (J75EII type, manufactured by Nippon Steel Works), and repeatedly molded into injection molded sheets (60mm width × 60mm length × 3mm thickness) at a resin temperature of 220°C and a molding cycle of 23 seconds. Using a colorimeter (CM-3700d, manufactured by Konica Minolta), the yellow index (initial YI) and L* values ​​under transmitted light in the thickness direction of the injection molded sheets obtained from the 10th to the 20th injection were measured, and the average values ​​were calculated. A lower YI value indicates no yellow tinge and excellent quality, while a higher L* value indicates higher brightness.

[0364] (7) Evaluation method for the hue of polycarbonate resin retained under heating condition

[0365] In the initial color evaluation of the polycarbonate resin, the molding cycle for producing the injection molded sheet using an injection molding machine was set to 60 seconds after the 20th injection, and this molding operation was repeated until the 30th injection. Furthermore, the YI value of the injection molded article obtained after the 30th injection under transmitted light in the thickness direction was measured using the aforementioned colorimeter, and the average value was calculated.

[0366] (8) Determination of light transmittance at wavelengths of 350 nm and 320 nm

[0367] Using a UV-Vis spectrophotometer (Hitachi High-Technologies U2900), the light transmittance in the thickness direction of the injection-molded sheet (width 60mm × length 60mm × thickness 3mm, from the 10th to the 20th injection) obtained in (6) above was measured, and its average value was calculated and evaluated.

[0368] (9) The ratio of the number of moles of H atoms bonded to the aromatic ring (A) to the total number of moles of H atoms (A+B) (where (B) is the number of moles of H atoms not bonded to the aromatic ring)

[0369] The spectrum of deuterated chloroform with pre-added tetramethylsilane (TMS) as an internal standard was measured only to determine the signal ratio of residual H in TMS to that in deuterated chloroform. Next, 30 mg of polycarbonate resin was weighed and dissolved in approximately 0.7 mL of the aforementioned deuterated chloroform. This solution was added to a 5 mm inner diameter NMR tube and the NMR was performed at room temperature using a JNM-AL400 (resonance frequency 400 MHz) manufactured by JEOL Ltd. 1 ¹H NMR spectroscopy was performed. The integral value of the signal appearing in the NMR spectrum at 6.5 ppm to 8.0 ppm was subtracted from the integral value of the signal of residual H in deuterated chloroform (obtained from the integral value of the TMS signal and the previously calculated ratio of TMS to residual H in deuterated chloroform), and this difference was set as 'a'. On the other hand, since the integral value of the signal appearing in the 0.5 ppm to 6.5 ppm was set as 'b', a / (a+b) = A / (A+B), this value was also obtained.

[0370] (10) Metal halide lamp irradiation test

[0371] Using a SUGA TEST INSTRUMENTS metal lamp weathering tester M6T, under conditions of 63°C and 50% relative humidity, a horizontal metal lamp was installed as the light source, a quartz inner filter was used, and a #500 filter was installed around the lamp as an outer filter. The irradiance was set to 1.5 kW / m² for a wavelength of 300 nm to 400 nm. 2 The square surface of the 20th injection plate (60mm width × 60mm length × 3mm thickness) obtained in (6) above was subjected to 100 hours of irradiation treatment. The YI value after irradiation was measured in the same manner as in (6) above.

[0372] The abbreviated symbols of the compounds used in the following examples are as follows.

[0373] ISB: Isosorbide (manufactured by Roquette Freres, trade name POLYSORB)

[0374] CHDM: 1,4-cyclohexanediethanol (Examples 1 and 2 are SKY CHDM manufactured by Shin Nippon Rikan Chemical; Example 3 is manufactured by Eastman Co., Ltd.)

[0375] DEG: Diethylene glycol (manufactured by Mitsubishi Chemical Co., Ltd.)

[0376] BPA: Bisphenol A (manufactured by Mitsubishi Chemical Co., Ltd.)

[0377] DPC: Diphenyl carbonate (manufactured by Mitsubishi Chemical Co., Ltd.)

[0378] (Example 1)

[0379] [Example 1-1]

[0380] In a polymerization reactor equipped with a stirrer and a reflux cooler controlled at 100°C, ISB, CHDM, DPC (which is distilled to reduce chloride ion concentration to below 10 ppb), and calcium acetate monohydrate are added in the following molar ratio: ISB / CHDM / DPC / calcium acetate monohydrate = 0.70 / 0.30 / 1.00 / 1.3 × 10⁻⁶. -6 The mixture was thoroughly purged with nitrogen (oxygen concentration 0.0005 vol%–0.001 vol%). Heating was then initiated using a heat transfer medium, and stirring was started when the internal temperature reached 100°C, maintaining the internal temperature at 100°C while ensuring uniform melting of the contents. The temperature was then increased to 210°C over 40 minutes. Upon reaching 210°C, this temperature was maintained while simultaneously reducing the pressure. After reaching 210°C, the pressure was increased to 13.3 kPa (absolute pressure, the same below) over 90 minutes, and maintained at this pressure for another 60 minutes. The phenol vapor, a byproduct of the polymerization reaction, was introduced into a reflux cooler using vapor with an inlet temperature controlled at 100°C as refrigerant. A small amount of monomer contained in the phenol vapor was returned to the polymerization reactor. The uncondensed phenol vapor was then fed into a condenser using 45°C warm water as refrigerant for recovery.

[0381] The oligomerized contents are temporarily restored to atmospheric pressure and then transferred to another polymerization reactor equipped with a stirrer and a similarly controlled reflux cooler. Heating and depressurization are initiated, and the internal temperature is brought to 220°C and the pressure to 200 Pa over 60 minutes. Subsequently, the internal temperature is reduced to below 230°C and the pressure to below 133 Pa over 20 minutes, and then restored to atmospheric pressure at the desired stirring force. The contents are then removed in thread form and granulated using a rotary cutter.

[0382] Using a twin-screw extruder (LABOTEX30HSS-32) manufactured by Nippon Steel Works with two vents, the resin was extruded in filament form at an outlet temperature of 250°C. The resulting granules were then cooled and cured with water, followed by granulation using a rotary cutter. At this time, the vents were connected to a vacuum pump, and the pressure at the vents was controlled at 500 Pa. The analytical results of the obtained polycarbonate resin and the evaluation results using the above methods are shown in Table 1. A polycarbonate resin with low yellowness, excellent brightness, and good hue was obtained, and the polycarbonate resin also exhibited good lightfastness.

[0383] [Examples 1-2]

[0384] Except for changing the molar ratio of ISB to CHDM, the process was carried out in the same manner as in Example 1-1. As in Example 1-1, a polycarbonate resin with low yellowness, excellent brightness, and good hue was obtained, and the polycarbonate resin also exhibited good lightfastness.

[0385] [Examples 1-3]

[0386] The molar ratios of ISB, CHDM, DPC, and calcium acetate monohydrate were: ISB / CHDM / DPC / calcium acetate monohydrate = 0.70 / 0.30 / 1.00 / 2.5 × 10⁻⁶. -6 The feeding process was carried out in the same manner as in Example 1-1, except that the materials were fed in the same way. As in Example 1-1, a polycarbonate resin with low yellowness, excellent brightness, and good hue was obtained, and the polycarbonate resin also had good lightfastness.

[0387] [Examples 1-4]

[0388] The molar ratios of ISB, CHDM, DPC, and calcium acetate monohydrate were: ISB / CHDM / DPC / calcium acetate monohydrate = 0.70 / 0.30 / 1.00 / 0.9 × 10⁻⁶. -6 The feeding process was carried out in the same manner as in Example 1-1, except that the materials were fed into the polycarbonate resin. Compared with Example 1-1, a polycarbonate resin with less yellowness, better brightness, and better hue was obtained, and the polycarbonate resin also had good lightfastness.

[0389] [Examples 1-5]

[0390] The procedure was carried out in the same manner as in Examples 1-3, except that magnesium acetate tetrahydrate was used instead of calcium acetate monohydrate. As in Examples 1-3, a polycarbonate resin with low yellowness, excellent brightness, and good hue was obtained, and the polycarbonate resin also exhibited good lightfastness.

[0391] [Examples 1-6]

[0392] The procedure was carried out in the same manner as in Examples 1-3, except that barium acetate was used instead of calcium acetate monohydrate. As in Examples 1-3, a polycarbonate resin with low yellowness, excellent brightness, and good hue was obtained, and the polycarbonate resin also exhibited good lightfastness.

[0393] [Examples 1-7]

[0394] The procedure was carried out in the same manner as in Examples 1-3, except that lithium acetate was used instead of calcium acetate monohydrate. As in Examples 1-3, a polycarbonate resin with low yellowness, excellent brightness, and good hue was obtained, and the polycarbonate resin also exhibited good lightfastness.

[0395] [Examples 1-8]

[0396] The procedure was carried out in the same manner as in Examples 1-3, except that DEG was used instead of CHDM. As in Examples 1-3, a polycarbonate resin with low yellowness, excellent brightness, and good hue was obtained, and the polycarbonate resin also exhibited good lightfastness.

[0397] [Examples 1-9]

[0398] Except for omitting the pressure reduction operation through the extruder vent, the procedure was carried out in the same manner as in Examples 1-3. Compared to Examples 1-3, the UV transmittance was slightly reduced.

[0399] [Examples 1-10]

[0400] Instead of calcium acetate monohydrate, cesium carbonate was used, and the final polymerization temperature was set to 226°C. Otherwise, the process was the same as in Examples 1-3. The lightfastness was slightly reduced compared to Examples 1-3.

[0401] [Comparative Example 1-1]

[0402] The procedure was carried out in the same manner as in Examples 1-3, except that cesium carbonate was used instead of calcium acetate monohydrate. Compared with Examples 1-3, the ultraviolet transmittance decreased, the YI value increased, and the brightness and lightfastness both deteriorated.

[0403] [Comparative Examples 1-2]

[0404] The molar ratios of ISB, CHDM, BPA, DPC, and calcium acetate monohydrate are: ISB / CHDM / BPA / DPC / calcium acetate monohydrate = 0.70 / 0.20 / 0.10 / 1.00 / 2.5 × 10⁻⁶. -6 The feeding process was carried out in the same manner as in Examples 1-3, except that the ultraviolet transmittance was reduced, the YI value was increased, and the brightness and lightfastness were both worse.

[0405] [Comparative Examples 1-3]

[0406] Except that the final polymerization temperature was set at 260°C, the process was the same as in Examples 1-3. Compared to Examples 1-3, the UV transmittance decreased, the YI value increased, and the brightness and lightfastness both deteriorated.

[0407] [Comparative Examples 1-4]

[0408] Cesium carbonate was added as shown in Table 1 instead of calcium acetate monohydrate; the final stage of polymerization was carried out at a temperature of 250°C; otherwise, it was carried out in the same manner as in Examples 1-3. Compared with Examples 1-3, the ultraviolet transmittance decreased, the YI value increased, and the brightness and lightfastness deteriorated.

[0409]

[0410] (Example 2)

[0411] [Example 2-1]

[0412] In a polymerization reactor equipped with a stirrer and a reflux cooler controlled at 100°C, ISB, CHDM, DPC (which is distilled and purified to a chloride ion concentration of less than 10 ppb), and calcium acetate monohydrate are mixed in the following molar ratio: ISB / CHDM / DPC / calcium acetate monohydrate = 0.70 / 0.30 / 1.00 / 1.3 × 10⁻⁶. -6Feeding is initiated, followed by thorough nitrogen purging (oxygen concentration 0.0005 vol%–0.001 vol%). Heating is then performed using a heat transfer medium, and stirring is initiated when the internal temperature reaches 100°C, maintaining the internal temperature at 100°C while ensuring uniform melting of the contents. Heating is then increased to 210°C over 40 minutes. Upon reaching 210°C, this temperature is maintained while simultaneously reducing the pressure. After reaching 210°C, the pressure is increased to 13.3 kPa (absolute pressure, the same below) over 90 minutes, and maintained at this pressure for another 60 minutes. The phenol vapor, a byproduct generated during the polymerization reaction, is introduced into a reflux cooler using vapor controlled at 100°C as refrigerant (measured at the inlet of the reflux cooler). A small amount of monomer contained in the phenol vapor is returned to the polymerization reactor. The uncondensed phenol vapor is then fed into a condenser using 45°C warm water as refrigerant for recovery.

[0413] The oligomerized contents are temporarily restored to atmospheric pressure and then transferred to another polymerization reactor equipped with a stirrer and a similarly controlled reflux cooler. Heating and depressurization are initiated, and the internal temperature is brought to 220°C and the pressure to 200 Pa over 60 minutes. Subsequently, the internal temperature is reduced to below 228°C and the pressure to below 133 Pa over 20 minutes, and then restored to atmospheric pressure at the desired stirring force. The contents are then removed in thread form and granulated using a rotary cutter.

[0414] Using a twin-screw extruder (LABOTEX30HSS-32) manufactured by Nippon Steel Works with two vents, the resin temperature at the outlet was set to 250°C. The resulting granules were extruded in a filament form, cooled and cured with water, and then granulated using a rotary cutter. At this time, the vents were connected to a vacuum pump, and the pressure at the vents was controlled at 500 Pa. The analytical results of the obtained polycarbonate resin and the results evaluated using the above methods are listed in Table 2. A polycarbonate resin with low yellowness, excellent brightness, and good hue was obtained, and the lightfastness of this polycarbonate resin was also good.

[0415] [Example 2-2]

[0416] Except for changing the molar ratio of ISB to CHDM, the process was carried out in the same manner as in Example 2-1. Similar to Example 2-1, a polycarbonate resin with low yellowness, excellent brightness, and good hue was obtained, and the polycarbonate resin also exhibited good lightfastness.

[0417] [Examples 2-3]

[0418] The molar ratios of ISB, CHDM, DPC, and calcium acetate monohydrate were: ISB / CHDM / DPC / calcium acetate monohydrate = 0.70 / 0.30 / 1.00 / 2.5 × 10⁻⁶. -6 The feeding process was carried out in the same manner as in Example 2-1, except that... As in Example 2-1, a polycarbonate resin with low yellowness, excellent brightness, and good hue was obtained, and the polycarbonate resin also exhibited good lightfastness.

[0419] [Examples 2-4]

[0420] The molar ratios of ISB, CHDM, DPC, and calcium acetate monohydrate were: ISB / CHDM / DPC / calcium acetate monohydrate = 0.70 / 0.30 / 1.00 / 0.9 × 10⁻⁶. -6 The feeding process was carried out in the same manner as in Example 2-1, except that the materials were fed into the polycarbonate resin. Compared with Example 2-1, a polycarbonate resin with less yellowness, better brightness, and better hue was obtained, and the polycarbonate resin also had good lightfastness.

[0421] [Examples 2-5]

[0422] The procedure was carried out in the same manner as in Examples 2-3, except that magnesium acetate tetrahydrate was used instead of calcium acetate monohydrate. As in Examples 2-3, a polycarbonate resin with low yellowness, excellent brightness, and good hue was obtained, and the polycarbonate resin also exhibited good lightfastness.

[0423] [Examples 2-6]

[0424] The procedure was carried out in the same manner as in Examples 2-3, except that barium acetate was used instead of calcium acetate monohydrate. As in Examples 2-3, a polycarbonate resin with low yellowness, excellent brightness, and good hue was obtained, and the polycarbonate resin also exhibited good lightfastness.

[0425] [Examples 2-7]

[0426] The procedure was carried out in the same manner as in Examples 2-3, except that lithium acetate was used instead of calcium acetate monohydrate. As in Examples 2-3, a polycarbonate resin with low yellowness, excellent brightness, and good hue was obtained, and the polycarbonate resin also exhibited good lightfastness.

[0427] [Examples 2-8]

[0428] The procedure was carried out in the same manner as in Examples 2-3, except that DEG was used instead of CHDM. As in Examples 2-3, a polycarbonate resin with low yellowness, excellent brightness, and good hue was obtained, and the polycarbonate resin also exhibited good lightfastness.

[0429] [Examples 2-9]

[0430] Examples 2-3 were performed similarly, except that the pressure reduction operation through the extruder vent was omitted. The UV transmittance was slightly lower compared to Examples 2-3.

[0431] [Example 2-10]

[0432] Instead of using calcium acetate monohydrate, cesium carbonate was added as shown in Table 2, and the final polymerization temperature was set to 250°C. Otherwise, the process was carried out in the same manner as in Examples 2-3. The lightfastness was slightly reduced compared to Examples 2-3.

[0433] [Comparative Example 2-1]

[0434] Instead of calcium acetate monohydrate, cesium carbonate was used, resulting in a final polymerization temperature of 230°C. Otherwise, the process was the same as in Examples 2-3. Compared to Examples 2-3, the UV transmittance decreased, the YI value increased, and both brightness and lightfastness deteriorated.

[0435] [Comparative Example 2-2]

[0436] The molar ratios of ISB, CHDM, BPA, DPC, and calcium acetate monohydrate are: ISB / CHDM / BPA / DPC / calcium acetate monohydrate = 0.70 / 0.20 / 0.10 / 1.00 / 2.5 × 10⁻⁶. -6 Feeding was carried out; the final polymerization temperature was set to 230°C; otherwise, the process was carried out in the same manner as in Examples 2-3. Compared with Examples 2-3, the ultraviolet transmittance decreased, the YI value increased, and the brightness and lightfastness both deteriorated.

[0437] [Comparative Examples 2-3]

[0438] Except that the final polymerization temperature was set at 260°C, the process was the same as in Examples 2-3. Compared to Examples 2-3, the UV transmittance decreased, the YI value increased, and both brightness and lightfastness deteriorated.

[0439] [Comparative Examples 2-4]

[0440] Instead of calcium acetate monohydrate, cesium carbonate was used, and the final polymerization temperature was set to 226°C. Otherwise, the process was the same as in Examples 2-3. Compared to Examples 2-3, the lightfastness was worse.

[0441]

[0442] (Example 3)

[0443] [Example 3-1]

[0444] In a polymerization reactor equipped with a stirrer and a reflux cooler controlled at 100°C, ISB, CHDM, DPC (which is distilled and purified to a chloride ion concentration below 10 ppb), and calcium acetate monohydrate are added, with the molar ratio of ISB / CHDM / DPC / calcium acetate monohydrate = 0.70 / 0.30 / 1.00 / 1.3 × 10⁻⁶. -6 The mixture was thoroughly purged with nitrogen (oxygen concentration 0.0005 vol%–0.001 vol%). Heating was then carried out using a heat transfer medium, and stirring was initiated when the internal temperature reached 100°C, maintaining the internal temperature at 100°C while ensuring uniform melting of the contents. The temperature was then increased to 215°C over 40 minutes. Upon reaching 215°C, this temperature was maintained while simultaneously reducing the pressure. After reaching 215°C, the pressure was increased to 13.3 kPa (absolute pressure, the same below) over 90 minutes, and maintained at this pressure for another 60 minutes. The phenol vapor, a byproduct of the polymerization reaction, was introduced into a reflux cooler using vapor controlled at 100°C as a refrigerant (measured at the inlet of the reflux cooler). A small amount of monomer contained in the phenol vapor was returned to the polymerization reactor. The uncondensed phenol vapor was then fed into a condenser using 45°C warm water as a refrigerant for recovery.

[0445] The oligomerized contents are temporarily restored to atmospheric pressure and then transferred to another polymerization reactor equipped with a stirrer and a similarly controlled reflux cooler. Heating and depressurization are initiated, reaching an internal temperature of 220°C and a pressure of 200 Pa over 60 minutes. Subsequently, the internal temperature is reduced to below 230°C and the pressure to below 133 Pa over 20 minutes, and then restored to atmospheric pressure at the desired stirring force. The contents are then removed in thread form and granulated using a rotary cutter.

[0446] Using a twin-screw extruder (LABOTEX 30HSS-32) manufactured by Nippon Steel Works with two vents, the resin temperature at the outlet was set to 250°C. The resulting granules were extruded in a filament form, cooled and cured with water, and then granulated using a rotary cutter. At this time, the vents were connected to a vacuum pump, and the pressure at the vents was controlled at 500 Pa. The analytical results of the obtained polycarbonate resin and the results evaluated using the above method are listed in Table 3. A polycarbonate resin with low yellowness, excellent brightness, and good hue was obtained, and the lightfastness of this polycarbonate resin was also good.

[0447] [Example 3-2]

[0448] Except for changing the molar ratio of ISB to CHDM, the process was carried out in the same manner as in Example 3-1. Similar to Example 3-1, a polycarbonate resin with low yellowness, excellent brightness, and good hue was obtained, and the polycarbonate resin also exhibited good lightfastness.

[0449] [Example 3-3]

[0450] The molar ratios of ISB, CHDM, DPC, and calcium acetate monohydrate were: ISB / CHDM / DPC / calcium acetate monohydrate = 0.70 / 0.30 / 1.00 / 2.5 × 10⁻⁶. -6 The feeding process was carried out in the same manner as in Example 3-1, except that the materials were fed in the same way. As in Example 3-1, a polycarbonate resin with low yellowness, excellent brightness, and good hue was obtained, and the polycarbonate resin also had good lightfastness.

[0451] [Examples 3-4]

[0452] The molar ratios of ISB, CHDM, DPC, and calcium acetate monohydrate were: ISB / CHDM / DPC / calcium acetate monohydrate = 0.70 / 0.30 / 1.00 / 0.9 × 10⁻⁶. -6 The feeding process was carried out in the same manner as in Example 3-1, except that the materials were fed into the polycarbonate resin. Compared with Example 3-1, a polycarbonate resin with less yellowness, better brightness, and better hue was obtained, and the polycarbonate resin also had good lightfastness.

[0453] [Examples 3-5]

[0454] The procedure was carried out in the same manner as in Examples 3-3, except that magnesium acetate tetrahydrate was used instead of calcium acetate monohydrate. As in Examples 3-3, a polycarbonate resin with low yellowness, excellent brightness, and good hue was obtained, and the polycarbonate resin also exhibited good lightfastness.

[0455] [Examples 3-6]

[0456] The procedure was carried out in the same manner as in Examples 3-3, except that barium acetate was used instead of calcium acetate monohydrate. As in Examples 3-3, a polycarbonate resin with low yellowness, excellent brightness, and good hue was obtained, and the polycarbonate resin also exhibited good lightfastness.

[0457] [Examples 3-7]

[0458] The procedure was carried out in the same manner as in Examples 3-3, except that lithium acetate was used instead of calcium acetate monohydrate. As in Examples 3-3, a polycarbonate resin with low yellowness, excellent brightness, and good hue was obtained, and the polycarbonate resin also exhibited good lightfastness.

[0459] [Examples 3-8]

[0460] The procedure was carried out in the same manner as in Examples 3-3, except that DEG was used instead of CHDM. As in Examples 3-3, a polycarbonate resin with low yellowness, excellent brightness, and good hue was obtained, and the polycarbonate resin also exhibited good lightfastness.

[0461] [Examples 3-9]

[0462] In Example 3-1, by reducing the final stirring power setting for polymerization, polycarbonate resin particles with a specific viscosity of 0.40 dL / g and a phenol content of 3500 ppm by weight were obtained. These polycarbonate resin particles were melted in a single-screw extruder under a nitrogen atmosphere and with the barrel temperature set at 230°C. The melted particles were then introduced into a horizontal reactor (manufactured by Hitachi Industrial Equipment Technology Co., Ltd., with spectacle-shaped impellers and an effective internal volume of 6L). This horizontal reactor had two stirring shafts in the horizontal direction and two or more impellers discontinuously arranged on these shafts. The polycondensation reaction was carried out continuously for 60 minutes at a pressure of 133 Pa and an internal temperature of 230°C. The molten polycarbonate resin was extracted in the form of a filament and granulated using a rotary cutter. The resulting polycarbonate resin had a specific viscosity of 0.50 dL / g and a phenol concentration of 204 ppm by weight.

[0463] [Comparative Example 3-1]

[0464] The procedure was carried out in the same manner as in Example 3-1, except that cesium carbonate was used instead of calcium acetate monohydrate. Compared to Example 3-1, there was a tendency for decreased UV transmittance and increased initial YI value. Furthermore, both brightness and lightfastness deteriorated.

[0465] [Comparative Example 3-2]

[0466] Except for omitting the pressure reduction operation through the extruder vent, the procedure was performed in the same manner as Comparative Example 3-1. Compared to Comparative Example 3-1, the ultraviolet transmittance decreased, the initial YI value increased, and both brightness and lightfastness deteriorated.

[0467] [Comparative Example 3-3]

[0468] Except for the addition of calcium acetate monohydrate as described in Table 3, the procedure was the same as in Example 3-1. Compared to Example 3-1, the ultraviolet transmittance decreased, the initial YI value increased, and both brightness and lightfastness deteriorated.

[0469] [Comparative Examples 3-4]

[0470] The final polymerization stage temperature was set to 260°C, and the decompression operation via the vent in the extruder was not performed. Otherwise, the process was the same as in Example 3-3. Compared to Example 3-3, the UV transmittance decreased, the YI value increased, and both brightness and lightfastness deteriorated.

[0471]

[0472] <Example 4>

[0473] The physical properties or characteristics of polycarbonate are evaluated using the following methods.

[0474] (1) Determination of oxygen concentration

[0475] The oxygen concentration inside the polymerization reactor was measured using an oxygen analyzer (manufactured by AMI Corporation: 1000RS).

[0476] (2) Quantitative analysis of the amount of monomer and phenol distilled off

[0477] The weights of each monomer and phenol distilled off at each reaction stage were quantified by composition determined by liquid chromatography.

[0478] (3) Calculation of the ratio (by weight) of the total amount of distilled monomers to the total amount of raw monomers.

[0479] The ratio of the total amount of distilled monomers to the total amount of raw material monomers is calculated from the total amount of all monomers distilled, including diphenyl carbonate, as quantified in (2) above, and the total amount of all monomers added as raw materials.

[0480] (4) Determination of specific viscosity

[0481] A polycarbonate resin sample was dissolved using dichloromethane as a solvent to prepare a polycarbonate solution with a concentration of 0.6 g / dL. The viscosity was measured using an Ubbelohde viscometer manufactured by Moritomo Rika Kogyo Co., Ltd., at a temperature of 20.0℃ ± 0.1℃. The relative viscosity ηrel was calculated from the solvent outflow time t0 and the solution outflow time t using the following formula.

[0482] ηrel=t / t0

[0483] The specific viscosity ηsp is obtained from the relative viscosity using the following formula.

[0484] ηsp=(η-η0) / η0=ηrel-1

[0485] Divide the specific viscosity by the concentration c (g / dL) to obtain the specific viscosity ηsp / c. The higher this value, the larger the molecular weight.

[0486] (5) Determination of the ratio of structural units derived from each dihydroxy compound and the concentration of terminal phenyl groups in polycarbonate resin.

[0487] The structural units of each dihydroxy compound in polycarbonate resin were determined as follows: 30 mg of polycarbonate resin was weighed and dissolved in approximately 0.7 mL of deuterated chloroform to prepare a solution. This solution was then added to an NMR tube with an inner diameter of 5 mm, and NMR was performed at room temperature using a JNM-AL400 (resonance frequency 400 MHz) manufactured by JEOL Ltd. 1 ¹H NMR spectroscopy determination. The ratio of structural units originating from each dihydroxy compound is determined by the signal intensity ratio of the structural units attributed to each dihydroxy compound.

[0488] Using 1,1,2,2-tetrabromoethane as an internal standard, the procedure was performed in the same manner as described above. 1 The concentration of terminal phenyl groups was determined by ¹H NMR measurement and the ratio of signal intensity attributed to the internal standard and terminal phenyl groups.

[0489] (6) The deviation between the composition ratio of each dihydroxy compound added as a raw material and the ratio of structural units derived from each dihydroxy compound in the obtained polycarbonate resin.

[0490] The difference between the molar percentage of dihydroxy compound structural units in the polycarbonate resin calculated in (5) above and the molar percentage of dihydroxy compound added as a raw material is divided by the molar percentage of dihydroxy compound added as a raw material. The absolute value of the obtained value is used to determine the deviation. The larger the value, the greater the deviation.

[0491] (7) Determination of metal concentration in polycarbonate resin

[0492] Approximately 0.5 g of polycarbonate resin particles were accurately weighed into a microwave decomposition vessel manufactured by Perkin Elmer. 2 mL of 97% sulfuric acid was added, and the mixture was microwaved at 230°C for 10 minutes under a sealed environment. After cooling to room temperature, 1.5 mL of 68% nitric acid was added, and the mixture was microwaved at 150°C for 10 minutes under a sealed environment. The mixture was then cooled to room temperature again, and 2.5 mL of 68% nitric acid was added. The mixture was then microwaved again at 230°C for 10 minutes under a sealed environment until the contents were completely decomposed. After cooling to room temperature, the resulting liquid was diluted with pure water and quantified using an ICP-MS manufactured by ThermoQuest.

[0493] (8) Evaluation method of initial color tone of polycarbonate resin

[0494] Polycarbonate resin granules were dried at 110°C for 10 hours under a nitrogen atmosphere. Next, the dried polycarbonate resin granules were fed into an injection molding machine (J75EII type, manufactured by Nippon Steel Works), and repeatedly molded into injection molded sheets (60mm width × 60mm length × 3mm thickness) at a resin temperature of 220°C and a molding cycle of 23 seconds. Using a colorimeter (CM-3700d, manufactured by Konica Minolta), the yellow index (YI) and L* values ​​of the injection molded sheets obtained from the 10th to the 20th injections were measured under transmitted light in the thickness direction, and the average values ​​were calculated. A lower YI value indicates no yellow tint and excellent quality, while a higher L* value indicates higher brightness.

[0495] (9) Light transmittance at wavelengths of 350nm and 320nm

[0496] Using a UV-Vis spectrophotometer (Hitachi High-Technologies U2900), the light transmittance in the thickness direction of the injection-molded sheet (width 60mm × length 60mm × thickness 3mm, from the 10th to the 20th injection) obtained in (8) above was measured, and its average value was calculated and evaluated.

[0497] (10) Metal halide lamp irradiation test

[0498] Using a SUGA TEST INSTRUMENTS metal lamp weathering tester M6T, at 63°C and 50% relative humidity, a horizontal metal lamp was installed as the light source, a quartz inner filter, and a #500 filter was installed around the lamp as an outer filter. The irradiance was set to 1.5 kW / m² for a wavelength of 300 nm to 400 nm. 2 The square surface of the 20th injection plate (60mm wide × 60mm long × 3mm thick) obtained in (8) above was subjected to 100 hours of irradiation treatment. The YI value after irradiation was measured in the same manner as in (8) above.

[0499] The abbreviated symbols of the compounds used in the following examples are as follows.

[0500] ISB: Isosorbide (manufactured by Roquette Freres, trade name POLYSORB)

[0501] CHDM: 1,4-Cyclohexanediethanol (manufactured by Shin-Nippon Rikasha, trade name SKY CHDM)

[0502] DEG: Diethylene glycol (manufactured by Mitsubishi Chemical Co., Ltd.)

[0503] DPC: Diphenyl carbonate (manufactured by Mitsubishi Chemical Co., Ltd.)

[0504] [Example 4-1]

[0505] (Phase 1 response)

[0506] In a 40L polymerization reactor equipped with a heating medium jacket using oil as the heating medium, an agitator, and a condenser connected to a vacuum pump, 30.44 mol of ISB, 13.04 mol of CHDM, 43.48 mol of DPC (which was distilled and purified to a chloride ion concentration of less than 10 ppb), and an aqueous solution of calcium acetate monohydrate were added (the amount of calcium acetate monohydrate added was 1.25 × 10⁻⁶ per mol of all dihydroxy compounds). -6 The reaction mixture was prepared by first purging calcium acetate monohydrate (mol), followed by thorough nitrogen purging (oxygen concentration 0.0005 vol%–0.001 vol%). A reflux cooler using steam (inlet temperature 100°C) as refrigerant was installed on the condenser tube, and a condenser using warm water (inlet temperature 45°C) as refrigerant was installed downstream of the reflux cooler. Next, the heating medium was circulated in the reactor, and stirring was started when the reaction liquid (i.e., internal temperature) reached 100°C. The contents were allowed to melt uniformly while maintaining the internal temperature at 100°C. Heating was then initiated, and the internal temperature was raised to 220°C over 40 minutes. Pressure was then reduced at 220°C, and the pressure was adjusted to 13.3 kPa (absolute pressure, the same below) over 90 minutes. If pressure reduction was initiated, the phenol vapor generated in the reaction would rapidly begin to distill off. The temperature of the oil introduced into the heating medium jacket (heating medium jacket inlet temperature) was adjusted appropriately to maintain the internal temperature at a constant 220°C. During periods when phenol distillation is high, the temperature of the heating medium oil is set at 242°C; during other periods, the temperature is kept below 242°C.

[0507] After reaching 13.3 kPa, the pressure was maintained for another 60 minutes to obtain polycarbonate oligomers.

[0508] The byproduct phenol and distilled monomer generated during the polymerization reaction are partially condensed using a reflux condenser and returned to the polymerization reactor. Uncondensed phenol and uncondensed monomer from the reflux condenser are fed into a condenser for recovery. The phenol distilled in this stage represents 94% of the theoretical distillate.

[0509] (Phase 2 response)

[0510] The polycarbonate oligomer obtained in the first stage is fed into a polymerization reactor equipped with a heating medium jacket using oil as the heat medium, an agitator, and a condenser connected to a vacuum pump, under a nitrogen atmosphere. A reflux cooler using steam (inlet temperature 100°C) as the refrigerant is installed on the condenser, and a condenser using warm water (inlet temperature 45°C) as the refrigerant is installed downstream of the reflux cooler. A cold trap using dry ice as the refrigerant is also installed downstream of the condenser.

[0511] After the oligomer is conveyed, the pressure is reduced, and the internal temperature is brought to 220°C and the pressure to 200 Pa over 60 minutes. Then, the internal temperature is reduced to below 230°C and the pressure to below 133 Pa over 20 minutes, before being restored to atmospheric pressure at the predetermined stirring power. The contents are then removed in thread form and granulated using a rotary cutter. The time from when the pressure reaches 1 kPa to when the predetermined stirring power is reached is measured.

[0512] The byproducts phenol and distilled monomer generated during the polymerization reaction are partially condensed using a reflux cooler and returned to the polymerization reactor. Uncondensed phenol and uncondensed monomer from the reflux cooler are fed into a condenser for recovery. Further, the uncondensed fraction in the condenser is recovered using a cold trap located downstream of the condenser.

[0513] For the fractions recovered using reflux coolers, condensers, and cold traps at each reaction stage, their weight and composition were determined, and the distilled byproducts phenol and monomers were quantified. For the monomers distilled from each stage as determined in this way, their total weight was calculated, and the ratio of this total weight to the monomers added as feedstock was calculated, as shown in Table 4.

[0514] Using a twin-screw extruder (LABOTEX30HSS-32) manufactured by Nippon Steel Works with two vents, the resin temperature at the outlet was set to 250°C. The resulting granules were extruded in a linear fashion, cooled and cured with water, and then granulated using a rotary cutter. At this point, the vents were connected to a vacuum pump, and the pressure at the vents was controlled at 500 Pa.

[0515] The analytical results of the obtained polycarbonate resin and the evaluation results using the above methods are listed in Table 4. The monomer distillation was minimal, and the deviation between the ratio of dihydroxy compounds added as raw materials and the ratio of dihydroxy compound structural units in the obtained polycarbonate resin was small. A polycarbonate resin with low yellowness, excellent brightness, and good hue was obtained, and the polycarbonate resin also exhibited good lightfastness.

[0516] [Example 4-2]

[0517] The molar ratio of ISB to CHDM and the maximum temperature of the heat transfer medium in the first stage reaction were changed, but otherwise, the process was the same as in Example 4-1. Similar to Example 4-1, the monomer distillation was minimal, and the deviation between the ratio of dihydroxy compounds added as raw materials and the ratio of dihydroxy compound structural units in the obtained polycarbonate resin was small. A polycarbonate resin with low yellowness, excellent brightness, and good hue was obtained, and the polycarbonate resin also exhibited good lightfastness.

[0518] [Example 4-3]

[0519] Compared to the total amount of 2.50 × 10⁻⁶ mol of dihydroxy compound, this represents an increase of 2.50 × 10⁻⁶ mol per mol of total dihydroxy compound. -6 The temperature of the heat medium in the first stage reaction was set to a maximum of 244°C using calcium acetate monohydrate. Otherwise, the process was carried out in the same manner as in Example 4-1. Similar to Example 4-1, the monomer distillation was minimal, and the deviation between the ratio of dihydroxy compounds added as raw materials and the ratio of dihydroxy compound structural units in the obtained polycarbonate resin was small. A polycarbonate resin with low yellowness, excellent brightness, and good hue was obtained, along with good lightfastness.

[0520] [Example 4-4]

[0521] Relative to the addition of 0.90 × 10⁻⁶ per 1 mol of all dihydroxy compounds. -6 The temperature of the heat medium in the first stage reaction was set to a maximum of 239°C using calcium acetate monohydrate. Otherwise, the process was carried out in the same manner as in Example 4-1. Similar to Example 4-1, less monomer distillation was observed, resulting in a polycarbonate resin with a smaller deviation between the ratio of dihydroxy compounds added as raw materials and the ratio of dihydroxy compound structural units in the obtained polycarbonate resin. Furthermore, compared to Example 4-1, the polycarbonate resin exhibited lower yellowness, superior brightness, and better lightfastness.

[0522] [Examples 4-5]

[0523] Relative to the addition of 0.25 × 10⁻⁶ units of all dihydroxy compounds per 1 mol of total dihydroxy compound. -6 The reaction was carried out in the same manner as in Example 4-1, except that calcium acetate monohydrate was used to make the maximum temperature of the heat medium in the first stage reaction 233°C. Compared with Example 4-1, the polymerization rate of the second stage was reduced and the monomer distillation was slightly increased, but a polycarbonate resin with low yellowness, excellent brightness and good color tone was obtained, and the polycarbonate resin also had good light resistance.

[0524] [Examples 4-6]

[0525] Magnesium acetate tetrahydrate was used instead of calcium acetate monohydrate; the maximum temperature of the heat medium in the first stage reaction was changed; otherwise, it was carried out in the same manner as in Examples 4-3. Similar to Examples 4-3, the monomer distillation was less, and the deviation between the ratio of dihydroxy compounds added as raw materials and the ratio of dihydroxy compound structural units in the obtained polycarbonate resin was smaller. A polycarbonate resin with low yellowness, excellent brightness, and good hue was obtained, and the polycarbonate resin also exhibited good lightfastness.

[0526] [Examples 4-7]

[0527] Barium acetate was used instead of calcium acetate monohydrate; the maximum temperature of the heat medium in the first stage reaction was changed; otherwise, it was carried out in the same manner as in Examples 4-3. Similar to Examples 4-3, the monomer distillation was minimal, and the deviation between the ratio of dihydroxy compounds added as raw materials and the ratio of dihydroxy compound structural units in the obtained polycarbonate resin was small. A polycarbonate resin with low yellowness, excellent brightness, and good hue was obtained, and the polycarbonate resin also exhibited good lightfastness.

[0528] [Examples 4-8]

[0529] Lithium acetate was used instead of calcium acetate monohydrate; the maximum temperature of the heat medium in the first stage reaction was changed; otherwise, it was carried out in the same manner as in Examples 4-3. Similar to Examples 4-3, the monomer distillation was minimal, and the deviation between the ratio of dihydroxy compounds added as raw materials and the ratio of dihydroxy compound structural units in the obtained polycarbonate resin was small. A polycarbonate resin with low yellowness, excellent brightness, and good hue was obtained, and the polycarbonate resin also exhibited good lightfastness.

[0530] [Examples 4-9]

[0531] DEG was used instead of CHDM; the maximum temperature of the heat transfer medium in the first stage reaction was changed; otherwise, it was carried out in the same manner as in Examples 4-3. Similar to Examples 4-3, the monomer distillation was minimal, and the deviation between the ratio of dihydroxy compounds added as raw materials and the ratio of dihydroxy compound structural units in the obtained polycarbonate resin was small. A polycarbonate resin with low yellowness, excellent brightness, and good hue was obtained, and the polycarbonate resin also exhibited good lightfastness.

[0532] [Examples 4-10]

[0533] Instead of calcium acetate monohydrate, cesium carbonate was used; the maximum temperature of the heat medium in the first stage reaction was changed; otherwise, it was carried out in the same manner as in Examples 4-3. Compared with Examples 4-3, the monomer distillation was slightly increased, the polymerization time was increased, and the deviation between the ratio of dihydroxy compounds added as raw materials and the ratio of dihydroxy compound structural units in the obtained polycarbonate resin was also slightly increased.

[0534] [Example 4-11]

[0535] Compared to the total amount of 5.00 × 10⁻⁶ mol of dihydroxy compound, this represents a total input of 5.00 × 10⁻⁶ mol of dihydroxy compound. -6 mol calcium acetate monohydrate was added to change the maximum temperature of the heat medium in the first stage reaction to 248°C. Otherwise, the process was carried out in the same manner as in Example 4-1. Similar to Example 4-1, the deviation between the ratio of dihydroxy compounds added as raw materials and the ratio of dihydroxy compound structural units in the obtained polycarbonate resin was reduced, but slight discoloration was observed.

[0536] [Comparative Example 4-1]

[0537] Except for omitting or not using the reflux cooler in stages 1 and 2, the process was carried out in the same manner as in Examples 4-10. In stage 2, even after 180 minutes from the moment 1 kPa was reached, the predetermined power was not achieved, so the polymer was extracted. Not only was the amount of monomer distilled off excessive, and the ratio of dihydroxy compounds added as raw materials to the ratio of dihydroxy compound structural units in the obtained polycarbonate resin deviated significantly, but the yellowness and lightfastness also deteriorated.

[0538] [Comparative Example 4-2]

[0539] In the first stage, the raw material mixture was uniformly melted at 100°C, and the internal temperature was brought to 220°C in 60 minutes. When the internal temperature reached 220°C, the pressure was reduced and the pressure was adjusted to 13.3 kPa in 120 minutes. Otherwise, it was carried out in the same manner as Comparative Example 4-1.

[0540] In the second stage, even after 180 minutes from the moment 1 kPa was reached, the predetermined power was not achieved, so the polymer was extracted. The amount of monomer distilled off was reduced compared to Comparative Example 4-1, but was still considerable, and the ratio of dihydroxy compounds added as raw materials deviated significantly from the ratio of dihydroxy compound structural units in the obtained polycarbonate resin.

[0541] [Comparative Example 4-3]

[0542] In the first stage of the reaction, the raw material mixture was uniformly melted at 100°C, and the internal temperature was raised to 250°C over 40 minutes. Pressure was then reduced at the moment the internal temperature reached 250°C, and the pressure was adjusted to 13.3 kPa over 90 minutes, bringing the maximum temperature of the heat medium in the first stage of the reaction to 275°C. Otherwise, the process was the same as in Example 4-1. In the second stage, even after 180 minutes from the moment 1 kPa was reached, the predetermined kinetic energy was not achieved, and the polymer was extracted. The monomer distillation rate was high, and the ratio of dihydroxy compounds added as raw materials deviated significantly from the ratio of dihydroxy compound structural units in the obtained polycarbonate resin. Furthermore, the viscosity was low, making molding impossible.

[0543] [Reference Example]

[0544] (Phase 1 response)

[0545] In a 0.5 L glass polymerization reactor equipped with a stirrer and a condenser connected to a vacuum pump, 0.5 mol of ISB, 0.227 mol of CHDM, and 0.773 mol of DPC (which was distilled to reduce chloride ion concentration to below 10 ppb) were added. Calcium acetate monohydrate in aqueous solution was also added, with the amount of calcium acetate monohydrate added being 1.25 × 10⁻⁶ per mol of all dihydroxy compounds. -6 The reactor was then purged with nitrogen. Next, it was immersed in an oil bath, and stirring was started when the reaction solution (also known as the internal temperature) reached 100°C. The contents were allowed to dissolve uniformly while maintaining the internal temperature at 100°C. The temperature was then increased, reaching 220°C over 40 minutes. Upon reaching 220°C, the pressure was reduced, and adjusted to 13.3 kPa over 90 minutes. If the pressure was reduced, the phenol vapor generated in the reaction would rapidly begin to distill off. The oil bath temperature was adjusted appropriately to maintain a constant internal temperature of 220°C. During periods of increased phenol distillation, the oil bath temperature was maintained at 224°C; otherwise, it was kept below 224°C.

[0546] After reaching 13.3 kPa, the pressure was maintained for another 60 minutes to obtain polycarbonate oligomers.

[0547] The byproduct phenol and distilled monomer generated during the polymerization reaction are fed into a condenser (refrigerant inlet temperature 45°C) for recovery. The phenol distilled in this stage represents 90% of the theoretical distillate.

[0548] (Phase 2 response)

[0549] Next, while heating the oil bath, depressurization was initiated, and the internal temperature was brought to 220°C and the pressure to 200 Pa over 60 minutes. Then, the internal temperature was lowered to below 230°C and the pressure to below 133 Pa over 20 minutes, and the pressure was restored to atmospheric pressure at the predetermined stirring power. The contents were then extracted in the form of a thread. The time from when the pressure reached 1 kPa to when the predetermined stirring power was reached was measured. The phenol and distilled monomers generated as byproducts in the polymerization reaction were fed into a condenser (refrigerant inlet temperature 45°C) for recovery, similar to the reaction in stage 1. The fractions that did not condense in the condenser were recovered using a cold trap located downstream of the condenser.

[0550] For the fractions recovered using reflux coolers, condensers, and cold traps at each reaction stage, their weight and composition were determined, and the distilled byproducts phenol and monomers were quantified. For the monomers distilled from each stage as determined in this way, their total weight was calculated, and the ratio of this total weight to the monomers added as feedstock was calculated, as shown in Table 4.

[0551]

[0552] Although the invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various modifications or alterations can be made without departing from the spirit and scope of the invention. This application incorporates, by reference, the contents of Japanese Patent Application No. 2009-272413, filed November 30, 2009; Japanese Patent Application No. 2009-272414, filed November 30, 2009; Japanese Patent Application No. 2009-272415, filed November 30, 2009; and Japanese Patent Application No. 2009-281977, filed December 11, 2009.

[0553] Industrial applicability

[0554] The polycarbonate resin of the present invention exhibits excellent transparency, color tone, heat resistance, thermal stability, and mechanical strength, and also possesses excellent optical properties. Therefore, it can provide materials suitable for a wide range of applications, including: injection molding applications for electrical and electronic components, automotive components, etc.; film and sheet applications; applications for bottles and containers requiring heat resistance; lens applications such as camera lenses, aiming lenses, CCD and CMOS lenses; films and sheets such as retardation films, diffusers, and polarizing films used in liquid crystal and plasma displays; optical discs, optical materials, and optical components; and adhesive applications for fixing pigments, charge transfer agents, etc.

[0555] Furthermore, the method for manufacturing polycarbonate resin according to the present invention can effectively and stably produce polycarbonate resin with excellent light resistance, transparency, hue, heat resistance, thermal stability and mechanical strength, and stable performance.

Claims

1. A method for manufacturing a polycarbonate resin, comprising polycondensing a dihydroxy compound with a diester of the following general formula (2) in the presence of a catalyst using two or more reactors via a multi-stage transesterification reaction to obtain the polycarbonate resin, wherein: At least one of the reactors that distills the monohydroxy compound, a byproduct of the transesterification reaction, at a distillation rate of 20% or more of the theoretical distillate is a reactor having an internal volume of 20 L or more and equipped with a heating unit and a reflux cooler. The heating unit is used to heat the reactor using a heating medium, the temperature of which differs from the temperature of the reaction liquid in the reactor by 15°C to 30°C. The temperature of the refrigerant introduced into the reflux cooler is 45°C to 180°C at the inlet of the reflux cooler. The total amount of monomer distilled off during the entire reaction process is less than 10% by weight relative to the total amount of raw monomer. The highest temperature of the reaction solution during the entire reaction process was 230℃. The dihydroxy compound includes a dihydroxy compound having the part of the following general formula (1) as a partial structure, wherein the catalyst is a compound containing at least one metal selected from the group consisting of lithium and long-period type group 2 of the periodic table, and the amount of the metal-containing compound is less than 20 μmol relative to 1 mol of the dihydroxy compound. Furthermore, the polycarbonate resin contains less than 700 ppm by weight of aromatic monohydroxy compounds, and the total amount of sodium, potassium, and cesium in the polycarbonate resin, expressed as metals, is less than 0.8 ppm by weight. [Chemistry 7] This excludes cases where the part represented by the general formula (1) is part of -CH2-OH. [Chemistry 8] In general formula (2), A 1 and A 2 Each group is independently an aliphatic group with 1 to 18 carbon atoms, either substituted or unsubstituted, or an aromatic group, either substituted or unsubstituted. Among them, the dihydroxy compound having the part of the structure shown in general formula (1) is the compound shown in general formula (4) below. [Chemistry 9] ， The polycarbonate resin contains structural units derived from dihydroxy compounds having the portion shown in the general formula (1) as part of the structure, and structural units derived from at least one compound selected from the group consisting of aliphatic dihydroxy compounds and alicyclic dihydroxy compounds. When the number of moles of H atoms bonded to the aromatic ring in the polycarbonate resin is set as A, and the number of moles of H atoms bonded to sites other than the aromatic ring is set as B, then A / (A+B)≦0.

1. The 3mm thick molded body made from the polycarbonate resin has a light transmittance of more than 65% at a wavelength of 350nm.

2. The method for manufacturing polycarbonate resin according to claim 1, wherein, The catalyst is at least one metal compound selected from the group consisting of magnesium compounds and calcium compounds.

3. The method for manufacturing polycarbonate resin as described in claim 1, wherein, The total amount of lithium, sodium, potassium and cesium in the polycarbonate resin, expressed as metal content, is less than 0.8 ppm by weight.

4. The method for manufacturing polycarbonate resin according to claim 1, wherein, The polycarbonate resin contains less than 60 ppm by weight of the diester of the general formula (2).

5. The method for manufacturing polycarbonate resin according to claim 1, wherein, The concentration of the terminal groups represented by the following general formula (3) in the polycarbonate resin is 20 μeq / g or more and 160 μeq / g or less. [Chemistry 10] 。 6. The method for manufacturing polycarbonate resin according to claim 1, wherein, The 3mm thick molded body made from the polycarbonate has a light transmittance of more than 30% at a wavelength of 320nm.

7. The method for manufacturing polycarbonate resin according to claim 1, wherein, A 3mm thick molded body was formed from the polycarbonate and subjected to irradiance of 1.5kW / m² at a wavelength of 300nm–400nm using a metal halide lamp in an environment of 63°C and 50% relative humidity. 2 After the molded body was irradiated for 100 hours, the yellow index (YI) value based on ASTM D1925-70, measured using transmitted light, was below 12.

8. The method for manufacturing polycarbonate resin according to claim 1, wherein, The initial yellow index value of the 3mm thick molded body made from the polycarbonate is below 10.

9. The method for manufacturing polycarbonate resin according to claim 1, wherein, A molded body with a thickness of 3 mm is formed from the polycarbonate resin. The absolute value of the difference between the initial yellow index value of the molded body and the yellow index (YI) value obtained below is less than 6. The yellow index (YI) value is obtained by using a metal halide lamp with an irradiance of 1.5 kW / m² at a wavelength of 300 nm to 400 nm in an environment of 63°C and 50% relative humidity. 2 After the molded body was irradiated for 100 hours, the yellow index (YI) value based on ASTM D1925-70 was measured using transmitted light.

10. A method for manufacturing a polycarbonate resin molded article, comprising molding the polycarbonate resin manufactured by any one of claims 1 to 9 to obtain the molded article.

11. The method for manufacturing a polycarbonate resin molded article as described in claim 10, wherein, The polycarbonate resin molded article is obtained by injection molding.

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