Method for producing thermoplastic resin, and thermoplastic film

Abstract

To provide a method for producing a thermoplastic resin, capable of stably producing the thermoplastic resin containing a small amount of foreign matter even at the initial stage of starting the production of another resin in the case of producing a certain resin and then producing another resin in a resin production plant.SOLUTION: A method for producing a thermoplastic resin, the method including producing a first thermoplastic resin and a second thermoplastic resin that are different from each other, the first thermoplastic resin and the second thermoplastic resin each including a predetermined structural unit and a carbonate bond, the method including a step of producing the first thermoplastic resin as a step (A), a step of changing a supply ratio of raw materials as a step (B), and a step of producing the second thermoplastic resin as a step (C), the method not including a step of cleaning an inside of the reactor between the step (A) and the step (B).SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] Thermoplastic resins are widely used in industrial products such as injection molded products, extrusion molded products, and films. In recent years, as the range of uses for thermoplastic resins has diversified, users' demands for more advanced performance have increased, leading to demands for further improvements in quality. For example, in the case of optical films used as display components, higher resolution is required for smartphones and AR glasses, and this has led to a demand for reducing impurities in the resin.

[0003] On the other hand, while mass production using continuous production plants has been the mainstream method for manufacturing thermoplastic resins, in recent years, in order to respond to diverse industrial demands, there has been an increasing need to produce a wide variety of products in small quantities using the same equipment, or to produce in batch-type plants. In this case, switching work is required, but if the resin types before and after the switch are different, production must be stopped once, and the resin and degraded materials remaining in the reactor must be cleaned, and then the production process must be restarted (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-94029 Summary of the Invention [Problem to be solved by the invention]

[0005] However, restarting a production process for a different type of resin is inefficient because it involves an increase in the number of steps, and the inventors' investigations have revealed that cleaning the inside of the reactor is insufficient, resulting in a large amount of foreign matter in the resin in the initial production period after the switch.

[0006] The present invention has been made in light of the above-mentioned background, and aims to provide a method for producing a thermoplastic resin, which, when a certain resin is produced in a resin production plant and then another resin is produced, can stably produce a thermoplastic resin with little foreign matter even in the early stages of production of the other resin. [Means for solving the problem]

[0007] The present inventors have conducted extensive research in light of the above problems and have completed the following invention.

[0008] [1] A method for producing a first thermoplastic resin and a second thermoplastic resin that are different from each other, comprising: The first thermoplastic resin and the second thermoplastic resin each contain a structural unit represented by the following formula (1) and a carbonate bond, The method includes, as step (A), a step of supplying at least two or more raw materials to a reactor and causing a polymerization reaction in the reactor to produce the first thermoplastic resin, The method includes a step (B) after the step (A) of changing the feed ratio of the raw materials, Further, after the step (B), a step (C) of producing the second thermoplastic resin is included, The process does not include a step of cleaning the inside of the reactor between the step (A) and the step (B). Method for producing thermoplastic resins.

[0009] [ka]

[0010] [2] The raw materials of the first thermoplastic resin and the second thermoplastic resin both contain two common monomers, the two common monomers are monomer (a) and monomer (b), When the sum of the molar ratios of the structural units derived from the monomer (a) and the structural units derived from the monomer (b) contained in the first thermoplastic resin or the second thermoplastic resin is taken as 100 mol %, the molar ratio occupied by the structural units derived from the monomer (a) is taken as X (mol %), The method for producing a thermoplastic resin according to [1], wherein the X (mol %) differs by 1 or more between the first thermoplastic resin and the second thermoplastic resin.

[0011] [3] The method for producing a thermoplastic resin according to [2], wherein the X (mol %) differs by 10 or more between the first thermoplastic resin and the second thermoplastic resin.

[0012] [4] Using at least a first reactor and a second reactor, connecting the first reactor and the second reactor; supplying two or more raw material monomers to the first reactor; transferring at least a portion of the product produced in the first reactor to the second reactor, and causing a further polymerization reaction in the second reactor; The manufacturing method according to any one of [1] to [3].

[0013] [5] The method according to any one of [1] to [4], wherein the glass transition temperatures of the first thermoplastic resin and the second thermoplastic resin differ by 5°C or more.

[0014] [6] The method according to any one of [2] to [5], wherein the structural unit derived from the monomer (a) is a structural unit represented by the formula (1).

[0015] [7] The first thermoplastic resin and the second thermoplastic resin are polycarbonate resins; raw materials for the first thermoplastic resin and the second thermoplastic resin contain one or more dihydroxy compounds and one or more carbonate diesters; At least one step of carrying out a melt polycondensation reaction, The method for producing a thermoplastic resin according to any one of [1] to [6].

[0016] [8] A thermoplastic resin containing a structural unit represented by the following formula (1), 2 A thermoplastic resin film with no more than 100 foreign particles of 25 μm or larger per film.

[0017] [ka]

[0018] [9] A method for producing two different thermoplastic resins, comprising: The method includes, as step (A), a step of supplying at least two or more raw materials to a reactor and causing a polymerization reaction in the reactor to produce a first thermoplastic resin, The method includes a step (B) after the step (A) of changing the feed ratio of the raw materials, Further, after the step (B), a step (C) is included in which a second thermoplastic resin different from the first thermoplastic resin is produced, The process does not include a step of cleaning the inside of the reactor between the step (A) and the step (B). Method for producing thermoplastic resins. [Effects of the Invention]

[0019] According to the present invention, when two different types of resins are produced, a thermoplastic resin containing little foreign matter can be stably produced even in the early stages of production of the other resin. [Brief explanation of the drawings]

[0020] [Figure 1] FIG. 1 is a flow diagram showing an example of an apparatus for a raw material preparation step that can be used in the thermoplastic resin production method of the present invention. [Figure 2] FIG. 1 is a flow diagram showing an example of an apparatus for a polymerization step that can be used in the method for producing a thermoplastic resin of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0021] The following describes in more detail the embodiments of the present invention. However, the description of the constituent elements described below is an example of an embodiment of the present invention, and the present invention is not limited to these contents, and can be implemented in various modifications within the scope of its gist.

[0022] In this specification, the term "structural unit" refers to a partial structure constituting a resin, such as a partial structure sandwiched between adjacent linking groups in a resin, or a partial structure sandwiched between a polymerizable reactive group present at the terminal portion of a polymer and a linking group adjacent to the polymerizable reactive group. More specifically, in the case of a polycarbonate resin, a carbonyl group is the linking group, and a partial structure sandwiched between adjacent carbonyl groups is referred to as a structural unit.

[0023] <Method of manufacturing thermoplastic resin> The method for producing a thermoplastic resin of the present invention is a method for producing two different thermoplastic resins, and includes, as step (A), a step of supplying at least two or more raw materials to a reactor and causing a polymerization reaction in the reactor to produce a first thermoplastic resin, and includes, after step (A), as step (B), a step of changing the feed ratio of the raw materials, and further, after step (B), as step (C), a step of producing a second thermoplastic resin different from the first thermoplastic resin, and does not include a step of cleaning the inside of the reactor between steps (A) and (B).

[0024] In the above-mentioned production method, the "two different thermoplastic resins" are not particularly limited in type as long as they are thermoplastic resins made from a common raw material, and examples thereof include acrylonitrile butadiene styrene resin, acrylonitrile styrene resin, acrylic resin, polyacetal, modified polyphenylene ether, polyethylene terephthalate, polyethersulfone, polyarylate, polyether ether ketone, thermoplastic polyimide, polyamideimide, polyolefin resin, polyamide resin, polyester resin, and polycarbonate resin. Two different types of thermoplastic resins can be produced by changing the ratio of raw materials, and therefore may need to be copolymers as needed.

[0025] In step (A), a first thermoplastic resin is produced from at least two or more raw materials for producing the first thermoplastic resin. Thereafter, in step (B), the supply ratio of the at least two or more raw materials is changed, and in the subsequent step (C), a second thermoplastic resin is produced at the changed raw material supply ratio.

[0026] The above production method does not include a step of cleaning the inside of the reactor between steps (A) and (B). Conventionally, when different types of resins are produced using the same equipment, the inside of the equipment is cleaned after the production of the first resin is completed and before the production of the next resin is started to remove resin, deteriorated materials, etc. that may remain inside the equipment, and then the next raw material is supplied and production of the new resin is started. However, even if a cleaning step is provided in this way, a phenomenon in which foreign matter in the resin increases in the early stages of production of the subsequent resin is observed.

[0027] The inventors of the present invention have unexpectedly discovered that by simply changing the supply ratio of raw materials without providing a cleaning step between the production process of the first resin and the production process of the subsequent resin, the amount of foreign matter present in the initial stage of production in the resulting subsequent resin can be reduced, and have completed the present invention.

[0028] <Method for producing thermoplastic resin (preferred embodiment)> A preferred embodiment of the method for producing a thermoplastic resin of the present invention is a method for producing a first thermoplastic resin and a second thermoplastic resin which are different from each other, wherein the first thermoplastic resin and the second thermoplastic resin both contain a structural unit represented by the following formula (1) and a carbonate bond: The method includes, as step (A), a step of supplying at least two or more raw materials to a reactor and causing a polymerization reaction in the reactor to produce the first thermoplastic resin, The method includes a step (B) after the step (A) of changing the feed ratio of the raw materials, Further, after the step (B), a step (C) of producing the second thermoplastic resin is included, The process does not include a step of cleaning the inside of the reactor between the step (A) and the step (B). A method for producing thermoplastic resin.

[0029] [ka]

[0030] In the preferred embodiment of the method for producing a thermoplastic resin, the first and second thermoplastic resins, which are different from each other, contain a structural unit represented by formula (1) and a carbonate bond. That is, they are polycarbonate resins produced by polycondensation reactions using different raw material ratios.

[0031] The polycondensation reaction is carried out at high temperatures and under high vacuum, and by removing the monohydroxy compound by-produced from the carbonic acid diester (when diphenyl carbonate is used as the carbonic acid diester, the monohydroxy compound by-produced is phenol), the reaction equilibrium is shifted toward the product (polymer) and the molecular weight is increased.

[0032] (Raw materials for the first thermoplastic resin and the second thermoplastic resin (raw materials for the polycarbonate resin)) Dihydroxy compounds The polycarbonate resin of the present invention contains a structural unit derived from a dihydroxy compound represented by formula (1) (hereinafter, sometimes simply referred to as "structural unit (1)"). Examples of dihydroxy compounds represented by formula (1) include isosorbide (ISB), isomannide, and isoidet, which are stereoisomers. These may be used alone or in combination of two or more. Among these, isosorbide, which is obtained by dehydration condensation of sorbitol produced from various starches that are abundant and easily available as a plant-derived resource, is most preferred in terms of availability, ease of production, and properties of the resulting molded articles (e.g., heat resistance, impact resistance, surface hardness, carbon neutrality).

[0033] When the total amount of structural units derived from dihydroxy compounds in the polycarbonate resin is taken as 100 mol%, the molar ratio of structural unit (1) is not particularly limited, but is usually 10 mol% or more and 90 mol% or less, preferably 20 mol% or more, more preferably 25 mol% or more, and even more preferably 30 mol% or more. Depending on the application, 35 mol% or more is even more preferable, and 40 mol% or more is particularly preferable. The molar ratio is preferably 80 mol% or less, more preferably 75 mol% or less, and even more preferably 70 mol% or less. Depending on the application, 65 mol% or less is even more preferable, and 60 mol% or less is particularly preferable. Within the above range, practical heat resistance is maintained while excellent mechanical properties and chemical resistance are obtained.

[0034] The polycarbonate resin of the present invention may contain other structural units. Examples of compounds that form other structural units include aliphatic dihydroxy compounds, alicyclic dihydroxy compounds, ether-containing dihydroxy compounds, acetal-containing dihydroxy compounds, aromatic-containing dihydroxy compounds, and diester compounds. Note that polycarbonate resins partially incorporating structural units derived from diester compounds are called polyester carbonate resins. In this specification, polycarbonate resins include polyester carbonate resins.

[0035] Examples of the aliphatic dihydroxy compound include the following dihydroxy compounds: straight-chain aliphatic dihydroxy compounds such as ethylene glycol, 1,3-propanediol, 1,2-propanediol, 1,4-butanediol, 1,5-heptanediol, 1,6-hexanediol, 1,9-nonanediol, 1,10-decanediol, and 1,12-dodecanediol; and branched-chain aliphatic dihydroxy compounds such as 1,3-butanediol, 1,2-butanediol, neopentyl glycol, and hexylene glycol.

[0036] Examples of the alicyclic dihydroxy compound include the following dihydroxy compounds: dihydroxy compounds which are primary alcohols of alicyclic hydrocarbons, exemplified by 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, tricyclodecane dimethanol, pentacyclopentadecanedimethanol, 2,6-decalindimethanol, 1,5-decalindimethanol, 2,3-decalindimethanol, 2,3-norbornane dimethanol, 2,5-norbornane dimethanol, 1,3-adamantanedimethanol, and dihydroxy compounds derived from terpene compounds such as limonene; and dihydroxy compounds which are secondary or tertiary alcohols of alicyclic hydrocarbons, exemplified by 1,2-cyclohexanediol, 1,4-cyclohexanediol, 1,3-adamantanediol, hydrogenated bisphenol A, and 2,2,4,4-tetramethyl-1,3-cyclobutanediol.

[0037] Examples of the ether-containing dihydroxy compound include oxyalkylene glycols and dihydroxy compounds containing an acetal ring. Examples of the oxyalkylene glycol include diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, polypropylene glycol, and polytetramethylene glycol.

[0038] Examples of the acetal-containing dihydroxy compound that can be used include spiroglycol (also known as 3,9-bis(1,1-dimethyl-2-hydroxyethyl-2,4,8,10-tetraoxaspiro[5,5]undecane) and dioxane glycol (also known as 2-(1,1-dimethyl-2-hydroxyethyl)-5-ethyl-5-hydroxymethyl-1,3-dioxane).

[0039] As the aromatic-containing dihydroxy compound, for example, the following dihydroxy compounds can be used: 2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(3-methyl-4-hydroxyphenyl)propane, 2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane, 2,2-bis(4-hydroxy-3,5-diethylphenyl)propane, 2,2-bis(4-hydroxy-(3-phenyl)phenyl)propane, 2,2-bis(4-hydroxy-(3,5-diphenyl)phenyl)propane, 2,2-bis(4-hydroxy-3,5-dibromophenyl)propane, bis(4-hydroxyphenyl)methane, 1,1-bis(4-hydroxyphenyl)ethane, 2,2-bis(4-hydroxyphenyl)butane, 2,2-bis(4-hydroxyphenyl)pentane, 1,1-bis(4-hydroxyphenyl)-1-phenylethane, bis(4-hydroxyphenyl)diphenylmethane, 1,1-bis(4-hydroxyphenyl)-2-ethylhexyl San, 1,1-bis(4-hydroxyphenyl)decane, bis(4-hydroxy-3-nitrophenyl)methane, 3,3-bis(4-hydroxyphenyl)pentane, 1,3-bis(2-(4-hydroxyphenyl)-2-propyl)benzene, 1,3-bis(2-(4-hydroxyphenyl)-2-propyl)benzene, 2,2-bis(4-hydroxyphenyl)hexafluoropropane, 1,1-bis(4-hydroxyphenyl)cyclohexane, bis(4-hydroxyphenyl)sulfone, 2,4'-dihydroxydiphenylsulfone aromatic bisphenol compounds such as bis(4-hydroxyphenyl)sulfone, bis(4-hydroxyphenyl)sulfide, bis(4-hydroxy-3-methylphenyl)sulfide, bis(4-hydroxyphenyl)disulfide, 4,4'-dihydroxydiphenyl ether, and 4,4'-dihydroxy-3,3'-dichlorodiphenyl ether; dihydroxy compounds having an ether group bonded to an aromatic group such as 2,2-bis(4-(2-hydroxyethoxy)phenyl)propane, 2,2-bis(4-(2-hydroxypropoxy)phenyl)propane, 1,3-bis(2-hydroxyethoxy)benzene, 4,4'-bis(2-hydroxyethoxy)biphenyl, and bis(4-(2-hydroxyethoxy)phenyl)sulfone;9,9-bis(4-(2-hydroxyethoxy)phenyl)fluorene, 9,9-bis(4-hydroxyphenyl)fluorene, 9,9-bis(4-hydroxy-3-methylphenyl)fluorene, 9,9-bis(4-(2-hydroxypropoxy)phenyl)fluorene, 9,9-bis(4-(2-hydroxyethoxy)-3-methylphenyl)fluorene, 9,9-bis(4-(2-hydroxypropoxy)-3-methylphenyl)fluorene, 9,9-bis(4-(2-hydroxyethoxy) 9,9-bis(4-(2-hydroxyethoxy)-3-isopropylphenyl)fluorene, 9,9-bis(4-(2-hydroxyethoxy)-3-isobutylphenyl)fluorene, 9,9-bis(4-(2-hydroxyethoxy)-3-tert-butylphenyl)fluorene, 9,9-bis(4-(2-hydroxyethoxy)-3-cyclohexylphenyl)fluorene, 9,9-bis(4-(2-hydroxyethoxy)-3-phenylphenyl)fluorene, 9,9-bis(4-(2-hydroxyethoxy)-3,5-dimethylphenyl)fluorene, 9,9-bis(4-(2-hydroxyethoxy)-3-tert-butyl-6-methylphenyl)fluorene, 9,9-bis(4-(3-hydroxy-2,2-dimethylpropoxy)phenyl)fluorene, and other dihydroxy compounds having a fluorene ring;

[0040] Examples of the diester compound include the following dicarboxylic acids: aromatic dicarboxylic acids such as terephthalic acid, phthalic acid, isophthalic acid, 4,4'-diphenyldicarboxylic acid, 4,4'-diphenyletherdicarboxylic acid, 4,4'-benzophenonedicarboxylic acid, 4,4'-diphenoxyethanedicarboxylic acid, 4,4'-diphenylsulfonedicarboxylic acid, and 2,6-naphthalenedicarboxylic acid; alicyclic dicarboxylic acids such as 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, and 1,4-cyclohexanedicarboxylic acid; and aliphatic dicarboxylic acids such as malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, and sebacic acid. These dicarboxylic acid components can be used as raw materials for polyester carbonate resins as dicarboxylic acids themselves, but depending on the production method, dicarboxylic acid esters such as methyl esters and phenyl esters, or dicarboxylic acid derivatives such as dicarboxylic acid halides can also be used as raw materials.

[0041] Among the above-mentioned other structural units, aliphatic dihydroxy compounds and alicyclic dihydroxy compounds are preferred from the viewpoint of improving mechanical properties and fluidity during melt molding. Among them, 1,4-cyclohexanedimethanol and tricyclodecanedimethanol are preferred, and 1,4-cyclohexanedimethanol is particularly preferred.

[0042] When the total amount of structural units derived from dihydroxy compounds in the polycarbonate resin of the present invention is taken as 100 mol%, the molar ratio of the other structural units is typically 5 mol% or more and 90 mol% or less. The content is preferably 10 mol% or more, more preferably 20 mol% or more, even more preferably 25 mol% or more, and even more preferably 30 mol% or more. The molar ratio is preferably 80 mol% or less, more preferably 75 mol% or less, even more preferably 70 mol% or less, even more preferably 65 mol% or less, and particularly preferably 60 mol% or less. Within the above ranges, the excellent properties of the structural unit (1) are not significantly impaired, and the balance of other physical properties can be improved.

[0043] The use of aromatic-containing dihydroxy compounds or diester compounds, such as bisphenol compounds, as copolymerization components can sometimes improve the heat resistance of polycarbonate resins. However, the polycarbonate resin tends to have poor weather resistance if it contains a large number of aromatic structures. Furthermore, because there is a significant difference in the polymerization reactivity between bisphenol compounds or diester compounds and the dihydroxy compounds that form structural unit (1), the bisphenol compounds or diester compounds tend to remain in the terminal groups, making it difficult to obtain a high-molecular-weight polycarbonate resin and resulting in poor mechanical properties such as impact resistance. Increasing the reaction temperature to accelerate the reaction tends to cause thermal decomposition of structural unit (1), resulting in discoloration of the resulting polycarbonate resin. For these reasons, the content of structural units derived from aromatic-containing dihydroxy compounds or diester compounds is preferably 20 mol% or less, more preferably 10 mol% or less.

[0044] Carbonate diester The polycarbonate resin of the present invention can be obtained by polycondensing a dihydroxy compound and a carbonic acid diester through a transesterification reaction. The carbonic acid diester used in the method of the present invention is preferably a compound represented by the following formula (4):

[0045] [ka]

[0046] (4) R in Eq. 1 , R 2 are each a hydrogen atom, an optionally substituted alkyl group having 1 to 10 carbon atoms, an optionally substituted acyl group having 1 to 10 carbon atoms, an optionally substituted alkoxy group having 1 to 10 carbon atoms, or an optionally substituted alkyl ester group having 1 to 10 carbon atoms.

[0047] Among the carbonate diesters represented by the formula (4), diphenyl carbonate is particularly preferred from the viewpoints of reactivity and availability.

[0048] In the polycondensation reaction, a monohydroxy compound is by-produced from the carbonate diester. When diphenyl carbonate is used as the carbonate diester, phenol is by-produced.

[0049] (polymerization catalyst) The polycondensation reaction proceeds in the presence of a transesterification catalyst (hereinafter, the transesterification catalyst will be referred to as the "polymerization catalyst"). The type of polymerization catalyst can have a significant effect on the reaction rate of the transesterification reaction and the quality of the resulting polycarbonate resin.

[0050] The polymerization catalyst is not particularly limited as long as it can satisfy the transparency, color tone, optical properties, heat resistance, and mechanical properties of the resulting polycarbonate resin. Examples of polymerization catalysts that can be used include metal compounds of Group 1 or Group 2 (hereinafter simply referred to as "Group 1" and "Group 2") in the long-form periodic table, as well as basic compounds such as basic boron compounds, basic phosphorus compounds, basic ammonium compounds, and amine compounds. Among these, Group 1 metal compounds and / or Group 2 metal compounds are preferred because of their good polymerization activity and the good color tone of the resulting polycarbonate resin.

[0051] Examples of Group 1 metal compounds include the following compounds: sodium hydroxide, potassium hydroxide, lithium hydroxide, cesium hydroxide, sodium hydrogen carbonate, potassium hydrogen carbonate, lithium hydrogen carbonate, cesium hydrogen carbonate, sodium carbonate, potassium carbonate, lithium carbonate, cesium carbonate, sodium acetate, potassium acetate, lithium acetate, cesium acetate, sodium stearate, potassium stearate, lithium stearate, cesium stearate, sodium borohydride, potassium borohydride, lithium borohydride, cesium borohydride, sodium phenylborohydride, potassium phenylborohydride, lithium phenylborohydride, cesium phenylborohydride, sodium benzoate, potassium benzoate, lithium benzoate, cesium benzoate, disodium hydrogen phosphate, dipotassium hydrogen phosphate, dilithium hydrogen phosphate, dicesium hydrogen phosphate, disodium phenylphosphate, phenylphosphate, Examples of the Group 1 metal compound include dipotassium phenylphosphate, dilithium phenylphosphate, dicesium phenylphosphate, alcoholates and phenolates of sodium, potassium, lithium and cesium, and disodium, dipotassium, dilithium and dicesium salts of bisphenol A. As the Group 1 metal compound, lithium compounds are preferred from the viewpoints of polymerization activity and the color tone of the resulting polycarbonate resin.

[0052] Examples of Group 2 metal compounds include the following compounds: calcium hydroxide, barium hydroxide, magnesium hydroxide, strontium hydroxide, calcium hydrogen carbonate, barium hydrogen carbonate, magnesium hydrogen carbonate, strontium hydrogen carbonate, calcium carbonate, barium carbonate, magnesium carbonate, strontium carbonate, calcium acetate, barium acetate, magnesium acetate, strontium acetate, calcium stearate, barium stearate, magnesium stearate, and strontium stearate. As the Group 2 metal compound, magnesium compounds, calcium compounds, or barium compounds are preferred, and from the viewpoints of polymerization activity and the color tone of the resulting polycarbonate resin, magnesium compounds and / or calcium compounds are more preferred, and calcium compounds are most preferred.

[0053] Although it is possible to use a basic compound such as a basic boron compound, a basic phosphorus compound, a basic ammonium compound, or an amine compound in combination with the Group 1 metal compound and / or Group 2 metal compound, it is more preferable to use only a Group 1 metal compound and / or a Group 2 metal compound, and from the viewpoint of the color tone of the resulting polycarbonate resin, it is most preferable to use only a Group 2 metal compound.

[0054] The amount of the polymerization catalyst used is preferably 0.1 μmol or more, more preferably 0.5 μmol or more, and particularly preferably 1 μmol or more, per mol of all dihydroxy compounds used in the reaction. The amount of the polymerization catalyst used is preferably 300 μmol or less, more preferably 100 μmol or less, and particularly preferably 50 μmol or less, per mol of all dihydroxy compounds used in the reaction. By adjusting the amount of the polymerization catalyst used within the above-mentioned range, the polymerization rate can be increased, and it becomes possible to obtain a polycarbonate resin with a desired molecular weight while keeping the polymerization temperature low and suppressing reactions that cause quality degradation such as coloration and thermal decomposition.

[0055] (Step (A), Step (C): Melt Polycondensation Reaction) In the method of the present invention, steps (A) and (C) are steps of polycondensation reaction of a dihydroxy compound, including a dihydroxy compound represented by formula (1), with a carbonate diester. The method of the present invention uses a melt polycondensation method. The melt polycondensation method does not use solvents or highly toxic compounds, so it can reduce the environmental burden and is excellent in productivity and quality stability.

[0056] When producing a resin by the melt polycondensation method, a dihydroxy compound, a carbonic acid diester, and a polymerization catalyst are mixed and subjected to a polycondensation reaction in a molten state, and the reaction rate is increased while removing elimination components from the system. Toward the end of the polymerization, the reaction is continued under high temperature and high vacuum conditions until the desired molecular weight is achieved. Once the reaction is complete, the molten resin is withdrawn from the reactor, yielding the polycarbonate resin of the present invention.

[0057] In the melt polycondensation reaction, the reaction rate and the molecular weight of the resulting resin can be controlled by strictly adjusting the molar ratio of all dihydroxy compounds to all diester compounds used in the reaction, and further, by changing the flow rate of the raw materials of the present invention during the production process, it is possible to control the terminal groups and obtain different resins. In the case of polycarbonate resins, the molar ratio of carbonate diester to all dihydroxy compounds is preferably adjusted to 0.80 to 1.20, more preferably 0.85 to 1.15, and particularly preferably 0.90 to 1.10.

[0058] By setting the molar ratio within the above range, a resin having a desired molecular weight can be produced. Furthermore, by ensuring that the molar ratio is at least as large as the lower limit, the amount of terminal hydroxy groups in the produced resin can be suppressed, which tends to improve the thermal stability of the resin, and the amount of unreacted dihydroxy compound remaining in the resulting polycarbonate resin can be reduced, which can suppress contamination of the molding machine in the subsequent molding step and poor appearance of the molded product. Furthermore, by ensuring that the molar ratio is equal to or less than the upper limit, it is possible to improve the rate of the transesterification reaction under the same conditions, or to suppress the amount of the carbonate diester or diester compound remaining in the produced polycarbonate resin, thereby suppressing problems caused by the residues in the molding step.

[0059] The melt polycondensation method is usually carried out in two or more multi-stage processes. The polymerization reaction may be carried out in two or more stages using one polymerization reactor by sequentially changing the reaction conditions, or may be carried out in two or more stages using two or more reactors by changing the conditions for each reactor. From the viewpoint of production efficiency, it is preferable to carry out the polymerization reaction using two or more, preferably three or more, reactors. The polymerization reaction may be carried out in a batch system, a continuous system, or a combination of a batch system and a continuous system, but from the viewpoint of production efficiency and quality stability, it is preferable to use a continuous system.

[0060] ·Raw material preparation process In order to maintain a constant reaction rate and the quality of the polycarbonate resin during the melt polycondensation reaction, it is necessary to strictly control the molar ratio of the dihydroxy compound to the carbonate diester compound. Since it is difficult to achieve the required quantitative accuracy using a method in which solids are supplied, the dihydroxy compound and carbonate diester compound used as raw materials for polycarbonate resin are usually handled as molten liquids in a batch, repetitive batch, or continuous stirred tank-type apparatus under an atmosphere of an inert gas such as nitrogen or argon.

[0061] In order to prevent the incorporation of foreign matter derived from the raw materials or from the outside, it is preferable that the molten raw materials are filtered through a filter before being supplied to the reactor. In the present invention, among the multiple raw materials used, any one of the raw materials or all of the raw materials may be filtered, and the method is not limited. A mixture of all the raw materials may be filtered, or the raw materials may be filtered separately and then mixed. In addition, the reaction liquid during the polycondensation reaction may be filtered through a filter. Although a filter may be installed on each raw material line, from the viewpoint of simplifying the equipment, it is preferable to mix all the raw materials and then pass them through a single filter.

[0062] ·Polymerization process In the polymerization process, it is important to properly control the balance between temperature and pressure in the reaction system. If either the temperature or pressure is changed too quickly, unreacted monomers may be distilled out of the reaction system. As a result, the molar ratio of the dihydroxy compound and the carbonate diester compound may change, and a resin with the desired molecular weight may not be obtained.

[0063] The polymerization rate is controlled by the balance between hydroxyl end groups and ester end groups. Therefore, particularly when polymerization is carried out in a continuous system, if the balance of end groups fluctuates due to the distillation of unreacted monomers, it becomes difficult to control the polymerization rate at a constant rate, and the molecular weight of the resulting resin may fluctuate greatly. Since the molecular weight of a resin is correlated with its melt viscosity, the melt viscosity of the resin produced in this manner may fluctuate during molding, which may lead to problems such as the inability to obtain molded products of uniform dimensions.

[0064] The following description will be given using the flow diagram of an example of a continuous polymerization process for polycarbonate resin shown in FIG. 2. In FIG. 2, a reactor can be used that combines four stirred reactors: three vertical stirred reactors (first vertical stirred reactor 21a, second vertical stirred reactor 21c, and third vertical stirred reactor 21e) and one horizontal stirred reactor (final reactor) 21g. Reflux condensers 21b and 21d are installed above the first vertical stirred reactor 21a and the second vertical stirred reactor 21c, respectively, for reflux. The pot liquid of the third vertical stirred reactor 21e is sent to the horizontal stirred reactor 21g by a gear pump 21f. Then, the gas components separated in the reflux condensers 21b and 21d at the top of the first vertical stirred reactor 21a and the second vertical stirred reactor 21c, and the gas components from the third vertical stirred reactor 21e and the horizontal stirred reactor 21g are recovered in the distillate recovery tank 23a while being cooled.

[0065] Specifically, the following conditions can be adopted as reaction conditions for the first-stage reaction. That is, the internal temperature of the polymerization reactor is set within a range of usually 130°C or higher, preferably 150°C or higher, more preferably 170°C or higher, and usually 250°C or lower, preferably 240°C or lower, more preferably 230°C or lower. The pressure of the polymerization reactor is set within a range of usually 70 kPa or lower (hereinafter, pressure refers to absolute pressure), preferably 50 kPa or lower, more preferably 30 kPa or lower, and usually 1 kPa or higher, preferably 3 kPa or higher, more preferably 5 kPa or higher. The reaction time is set within a range of usually 0.1 hour or higher, preferably 0.5 hour or higher, and usually 10 hours or lower, preferably 5 hours or lower, more preferably 3 hours or lower.

[0066] In the first reaction step, most of the monohydroxy compound produced as a by-product from the diester compound is distilled off outside the reaction system.

[0067] In the first stage reaction, lowering the vacuum pressure can accelerate the polymerization reaction, but it also increases the amount of unreacted monomer distilled off. To achieve both the suppression of unreacted monomer distillation and the promotion of the reaction by reducing the pressure, it is effective to use a reactor equipped with a reflux condenser. It is particularly effective to use a reflux condenser in the early stages of the reaction when there is a lot of unreacted monomer.

[0068] From the second stage onwards, it is preferable to gradually reduce the pressure of the reaction system from the pressure of the first stage, and ultimately reduce the pressure (absolute pressure) of the reaction system to 1 kPa or less while continuously removing the generated monohydroxy compound from the reaction system. The maximum internal temperature of the polymerization reactor is usually set in the range of 200 to 260°C, preferably 210 to 245°C, and particularly preferably 215 to 230°C. The reaction time in each stage is usually set in the range of 0.1 to 10 hours, preferably 0.5 to 5 hours, and particularly preferably 1 to 3 hours.

[0069] Once it is confirmed that the specified melt viscosity (molecular weight) has been reached using the stirring power as an indicator, nitrogen is introduced into the reactor to return the pressure to normal pressure and stop the polymerization reaction.The molten resin is then continuously extracted from the reactor and cooled to stop the polymerization reaction.

[0070] The molten resin is discharged from the die head in the form of strands, cooled and solidified, and then pelletized using a rotary cutter or the like. If necessary, extrusion devolatilization, extrusion kneading, and extrusion filtration processes may be added before pelletization. In these processes, additives are mixed into the resin, low-molecular-weight components are devolatilized using a vacuum vent, and foreign matter is removed using a polymer filter.

[0071] Specifically, the molten resin is continuously extracted from the fourth horizontal stirring reactor (final reactor) 21h using the gear pump 4b in Fig. 1. It is then sent to a vacuum vent twin-screw extruder 22a, and then sent to a die 22d via a polymer filter 22c by a gear pump 22b, where it is extruded in the form of strands, cooled and solidified, and pelletized using a rotary cutter or the like.

[0072] In the case of continuous polymerization, a method can be suitably employed in which the polycarbonate resin obtained in step (A) or step (C) is continuously fed to an extruder in a molten state without being solidified, and heat is applied to the resin by shear heat generated by the extruder.

[0073] In the method of the present invention, the polycarbonate resin obtained in step (A) or step (C), i.e., the polycarbonate resin extracted from the final reactor, is preferably supplied to the extruder while maintaining a molten state without being solidified. In this case, the molten resin can be subjected to the above-mentioned treatment in the extruder without coming into contact with air (oxygen), thereby suppressing coloration of the resin.

[0074] (Process (B): Process of changing the raw material supply ratio) The method for producing a thermoplastic resin of the present invention includes, after step (A) and before step (C), step (B) of changing the feed ratio of raw materials fed to a reactor.

[0075] The raw materials for the first thermoplastic resin and the second thermoplastic resin preferably contain two common monomers, where the two common monomers are monomer (a) and monomer (b), and the sum of the molar ratios of the structural units derived from monomer (a) and the structural units derived from monomer (b) contained in the first thermoplastic resin or the second thermoplastic resin is taken as 100 mol %, the molar ratio of the structural units derived from monomer (a) is defined as X (mol %), and it is preferable that X (mol %) differs between the first thermoplastic resin and the second thermoplastic resin by 1 or more. Furthermore, it is more preferable that X (mol %) differs between the first thermoplastic resin and the second thermoplastic resin by 10 or more, even more preferably by 13 or more, and particularly preferably by 15 or more.

[0076] The structural unit derived from the monomer (a) is preferably a structural unit represented by the following formula (1).

[0077] [ka]

[0078] Furthermore, the structural unit derived from the monomer (b) is preferably the above-mentioned "other structural unit."

[0079] In step (B), the raw material ratio is preferably changed, for example, by changing the supply amount ratio (molar ratio) of monomer (a) to monomer (b) to a ratio similar to the molar ratio of structural units derived from monomer (a) and monomer (b) in the resin to be obtained after changing the raw material ratio.

[0080] In the method for producing a thermoplastic resin of the present invention, first, in step (A), a first thermoplastic resin is produced, then, in step (B), the supply ratio of raw materials used in the production of the first thermoplastic resin is changed to another supply ratio, and then, in step (C), a second thermoplastic resin is produced at the different supply ratio.

[0081] Steps (A), (B), and (C) are carried out continuously, and a step of cleaning the inside of the reactor used between steps (A) and (C) is not included. Here, "used reactor" refers to all reactors used in steps (A) and (C), including reactors used in the raw material preparation step and polymerization step. Furthermore, "cleaning" includes washing monomers, oligomers, resins, and degraded materials that may remain in the reactor with an organic solvent, washing with an aqueous solution or water, or washing with raw materials to be used in a subsequent step.

[0082] <Characteristics of polycarbonate resin> (molecular weight) The molecular weight of a polycarbonate resin can be expressed, for example, by reduced viscosity. The higher the value obtained by these measurement methods, the higher the molecular weight. The reduced viscosity of the polycarbonate resin obtained by the method of the present invention is usually 0.20 dL / g or more and 2.00 dL / g or less, preferably 0.25 dL / g or more, more preferably 0.30 dL / g or more, even more preferably 0.35 dL / g or more, and even more preferably 0.40 dL / g or more. Furthermore, the reduced viscosity is preferably 1.40 dL / g or less, more preferably 1.20 dL / g or less, even more preferably 1.00 dL / g or less, and even more preferably 0.80 dL / g or less. By keeping the reduced viscosity within the above range, a resin with a good balance between mechanical properties and melt processability can be obtained. The method for adjusting the reduced viscosity is not particularly limited and can be carried out by a conventional method. For example, the reduced viscosity can be adjusted by finely adjusting the pressure, temperature, stirring speed, etc. in each reaction vessel while sampling a small amount of sample from the reactor and measuring the reduced viscosity.

[0083] The reduced viscosity of the polycarbonate resin (A) is measured using an Ubbelohde viscometer at a temperature of 20.0°C ± 0.1°C after precisely adjusting the concentration of the polycarbonate resin to 0.6 g / dL using methylene chloride as a solvent.

[0084] (glass transition temperature) The glass transition temperature of the polycarbonate resin is preferably 60°C or higher and 180°C or lower. The lower limit is more preferably 80°C or higher, and particularly preferably 90°C or higher. The upper limit is more preferably 160°C or lower, and particularly preferably 140°C or lower. Within the above range, the polycarbonate resin has sufficient heat resistance and is easy to mold.

[0085] In the method for producing a thermoplastic resin of the present invention, the glass transition temperatures of the first thermoplastic resin and the second thermoplastic resin preferably differ by 5°C or more, more preferably by 10°C or more, even more preferably by 15°C or more, and particularly preferably by 20°C or more.

[0086] (melt viscosity) The polycarbonate resin in the present invention is measured at a temperature of 240°C and a shear rate of 91.2 sec -1 The melt viscosity at 100 Pa·s or more and 10,000 Pa·s or less is preferred. The lower limit is more preferably 300 Pa·s or more, even more preferably 500 Pa·s or more, and particularly preferably 700 Pa·s or more. The upper limit is more preferably 8,000 Pa·s or less, and particularly preferably 6,000 Pa·s or less. By setting the viscosity within the above range, a resin with an excellent balance between mechanical properties and melt processability can be obtained.

[0087] (Number of foreign particles in the film) When a thermoplastic resin film is formed using the polycarbonate resin of the present invention, 1 m of the film 2 The number of foreign particles of 25 μm or more per particle is preferably 100 or less, and more preferably 80 or less. Note that the term "foreign particles" as used herein means particles having a major diameter of 25 μm or more.

[0088] (Number of foreign particles in the plate) Seven molded articles (plates) of 60 mm x 60 mm x 3.0 mm thick are produced using the polycarbonate resin of the present invention, and the number of foreign matter with a major axis of 50 μm or more on all seven plates (total number of foreign matter on seven plates) is preferably 1 or less, and more preferably zero.

[0089] <Additives> The polycarbonate resin obtained by the present invention may be blended with catalyst deactivators, antioxidants, heat stabilizers, light stabilizers, ultraviolet absorbers, release agents, lubricants, fillers such as fillers, antifogging agents, antiblocking agents, colorants, flame retardants, antistatic agents, conductivity-imparting agents, crosslinking agents, crosslinking aids, metal deactivators, molecular weight modifiers, antibacterial agents, fluorescent brightening agents, light diffusing agents, and the like, within the scope of not impairing the effects of the present invention.

[0090] Furthermore, for the purpose of improving the mechanical properties, solvent resistance, and other properties of the resin, the resin may be kneaded with one or more synthetic resins such as other polycarbonates, polyesters, polyamides, polystyrenes, polyolefins, acrylics, amorphous polyolefins, ABS, AS, and other rubbers to form a polymer alloy.

[0091] The additives and modifiers can be produced by mixing the resin obtained by the present invention with the above components simultaneously or in any order using a mixer such as a tumbler, V-blender, Nauta mixer, Banbury mixer, kneading roll, extruder, etc. Among these, kneading using an extruder, particularly a twin-screw extruder, is preferred from the viewpoint of improving dispersibility.

[0092] <Reasons why the present invention is effective> The reason why the present invention is effective is not yet clear, but is presumed to be as follows. If the production process includes a step of stopping the production of resin after its manufacture, there may be substances generated by depolymerization of the resin remaining in the reactor, or solid, liquid, or gel-like thermal degradation products (including carbonized products) generated by applying heat for a long period of time to resin remaining in the reactor that could not be removed by washing or other methods (for example, resin that was produced in the same production process prior to its manufacture). The present invention can provide a manufacturing method that does not generate such thermal degradation products and allows for stable production by continuously operating different thermoplastic resins.

[0093] <Uses of the thermoplastic resin (polycarbonate resin) obtained by the present invention (thermoplastic resin film, etc.)> The thermoplastic resin obtained by the present invention and a resin composition containing the same can be molded into a molded article by a commonly known method such as injection molding, extrusion molding, or compression molding, and a molded article having excellent optical properties, heat resistance, and mechanical strength can be obtained.

[0094] The thermoplastic resin film using the thermoplastic resin obtained by the method of the present invention is made of a thermoplastic resin containing a structural unit represented by the following formula (1), 2 The number of foreign particles of 25 μm or larger per unit area is 100 or less.

[0095] [ka]

[0096] As described above, since the number of foreign matters is small, the film of the present invention is suitable for optical applications, and can be suitably used, for example, as a film for displays, a film for smartphones, and a film for AR glasses. [Example]

[0097] The present invention will be described in more detail below using examples, but the present invention is not limited to the following examples as long as the gist of the invention is not exceeded.

[0098] [Measurement method] The various physical properties were measured according to the following methods.

[0099] < 1 H-NMR Approximately 15 mg of resin sample was weighed out and dissolved in approximately 0.7 mL of deuterated chloroform, and this was placed in an NMR tube with an inner diameter of 5 mm. 1 The H-NMR spectrum was measured, and the molar ratio of each structural unit derived from the raw material monomer used in the resin sample was calculated based on the obtained spectrum. That is, for example, in the case of a copolymerized polycarbonate resin using ISB and CHDM as dihydroxy compounds, the molar ratio of each structural unit was calculated based on the ratio of the signal intensities based on each structural unit of the copolymerized polycarbonate resin.

[0100] The apparatus and conditions used are as follows: Device: JNM-ECZ400S (manufactured by JEOL Ltd.) ·Measurement temperature: 30℃ Relaxation time: 6 seconds Number of times accumulated: 64

[0101] ISB and CHDM copolymer polycarbonate resin1 H-NMR analysis was carried out as follows. obtained 1 In the H-NMR spectrum, the relative area value obtained by integrating the signal intensity within each chemical shift range shown below was treated as the integral value of the signal derived from the protons derived from the following compounds.

[0102] [Table 1]

[0103] (Calculation of the value corresponding to the molar ratio of each structure) ·Total ISB-derived structural units (a´): (a) integral value / 4 Total CHDM-derived structural units (b´): (b) integral value / 10

[0104] (Difference in molar ratio of structural units in resin before and after changing raw material composition) the above 1 By H-NMR analysis, the absolute value of the difference in the molar ratio of structural units in the copolymerized polycarbonate resin before and after changing the monomer feed ratio was calculated.

[0105] <Foreign substances contained in the film> A single-screw extruder (diameter 20 mm, single flight, L / D = 25, cylinder temperature 240 °C), a cast film die (150 mm wide), and a cooling roll were used to extrude a film with a thickness of 35 μm ± 5 μm. The extruded film was measured inline over a 3 m time period using a film quality evaluation device (Optical Control System, model "FSA100") and a black-and-white camera. 2 Observe the film and use the fact that it appears white or gray to identify any black areas as foreign matter. 2 The number of foreign particles with a major axis of 25 μm or more observed per pellet (hereinafter simply referred to as "foreign particle count") was measured. The raw material composition was changed and equal amounts of pellets were collected and mixed immediately, 2 hours later, and 4 hours later, and the number of foreign particles in the pellets is shown in Table 1 as "film foreign particle count."

[0106] <Foreign matter contained in the plate> Using an injection molding machine (manufactured by The Japan Steel Works, Ltd., model "J50EII") and a mold temperature controller (manufactured by Matsui Manufacturing Co., Ltd., model "MCIII-15"), the cylinder temperature was set to 230°C, and seven molded products (plates) measuring 60 mm x 60 mm x 3.0 mm thick were molded. All seven molded products were checked in bright light using a magnifying glass with a scale. Taking advantage of the fact that the plates appeared white, transparent, or almost white, black, brown, or other dark-colored substances were identified as foreign matter, and the number of foreign matter with a major axis of 50 μm or more present across the entire plate (total number of foreign matter on the seven plates) was counted as the "number of foreign matter on the plate." The number of foreign particles in pellets that were collected immediately, 2 hours, and 4 hours after starting resin production with the raw material composition changed and mixed in equal amounts is shown in Table 1 as "number of foreign particles on plate."

[0107] <Glass transition temperature (Tg)> The glass transition temperature of the resin was measured using a differential scanning calorimeter (DSC6220, manufactured by SII NanoTechnology). Approximately 10 mg of resin sample was placed in a sealed aluminum pan manufactured by SII NanoTechnology and heated from 30 to 200 °C at a rate of 20 °C / min under a 50 mL / min nitrogen flow. After holding the temperature for 3 min, the sample was cooled to 30 °C at a rate of 20 °C / min. The sample was then held at 30 °C for 3 min and again heated to 200 °C at a rate of 20 °C / min. From the DSC (Differential Scanning Calorimetry) data obtained during the second heating run, the extrapolated glass transition onset temperature (Tg) was determined. This temperature was defined as the temperature at the intersection of a line drawn by extending the low-temperature baseline toward the high-temperature side and a tangent drawn at the point where the gradient of the step-like portion of the glass transition curve is maximum.

[0108] [Raw materials used] In the following Examples and Comparative Examples, the explanations and manufacturers of the compounds indicated by abbreviations are as follows:

[0109] <Dihydroxy compounds> ISB: Isosorbide (manufactured by Rocket Fleuret) CHDM: 1,4-cyclohexanedimethanol (SK Chemical Co., Ltd.) <Carbonate diester> DPC: Diphenyl carbonate (Mitsubishi Chemical Corporation)

[0110] <Catalyst deactivator> Phosphonic acid (Tokyo Chemical Industry Co., Ltd.) <Heat stabilizer (antioxidant)> Irganox 1010: Pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate) (BASF) AS2112: Tris(2,4-di-tert-butylphenyl)phosphite (ADEKA)

[0111] <Release agent> E-275: Ethylene glycol distearate (NOF Corporation) <UV absorber> SEESORB709: 2-(2-hydroxy-5-tert-octylphenyl)-2H-benzotriazole (Shipro Chemicals) <Polymerization catalyst> Calcium acetate monohydrate (Kanto Chemical Co., Ltd.) Calcium acetate monohydrate was dissolved in demineralized water to prepare an aqueous solution of a predetermined concentration.

[0112] (Measurement of reduced viscosity) Resin samples obtained in the following Examples and Comparative Examples were dissolved in methylene chloride to prepare resin solutions with a concentration of 0.6 g / dL. Measurements were carried out at a temperature of 20.0°C ± 0.1°C using an Ubbelohde viscometer manufactured by Moritomo Rika Kogyo Co., Ltd., to measure the solvent transit time t0 and the solution transit time t. The relative viscosity ηrel was calculated using the obtained values ​​of t0 and t according to the following formula (i), and the obtained relative viscosity η rel The specific viscosity ηsp was calculated using the following equation (ii). η rel =t / t0 (i) η sp =(η-η0) / η0=η rel-1 (ii) (η0 is the viscosity of the solvent.) Then, the obtained specific viscosity η sp Divide by the concentration c [g / dL] to obtain the reduced viscosity (η sp The higher this value, the larger the molecular weight.

[0113] [Example 1] 1 and 2, polymerization of polycarbonate resin was carried out using a continuous polymerization equipment using three vertical stirring reactors (21a, 21c, 21e), one horizontal stirring reactor 21g, and a twin-screw extruder 22a. Each continuous polymerization equipment was washed with phenol before use.

[0114] <Step (A-1): Production of polycarbonate resin (PC-1)> ISB, CHDM, and DPC were melted in their respective tanks, and the molten raw materials were continuously supplied to the first vertical stirred reactor 21a using pumps. At this time, the ratio of the amounts of the raw materials fed was adjusted so that the mass ratio and molar ratio of each structural unit in the resulting copolymeric polycarbonate resin would be as follows: Molar ratio: ISB:CHDM:DPC = 0.700:0.300:1.010 Mass ratio…ISB:CHDM:DPC=58.8:24.9:16.3 Thereafter, at the same time, an aqueous solution of calcium acetate monohydrate, which was a polymerization catalyst, was supplied to the first vertical stirred reactor 21a in an amount such that the amount of calcium acetate monohydrate was 1.5 μmol per 1 mol of the total dihydroxy compounds.

[0115] The internal temperature, internal pressure and residence time of the first to third vertical stirred reactors and the horizontal stirred reactors (21a, 21c, 21e and 21g) were adjusted as follows. First vertical stirred reactor 21a: 190°C, 25 kPa, 120 minutes, Second vertical stirred reactor 21c: 195°C, 10 kPa, 90 minutes, Third vertical stirred reactor 21e: 205°C, 4.0 kPa, 45 minutes Horizontal stirred reactor 21g: 220°C, 0.1-1.0 kPa, 120 min The horizontal stirred reactor 21g was operated while finely adjusting the internal pressure so that the resulting copolymeric polycarbonate resin would have a reduced viscosity of 0.41 to 0.45 dL / g.

[0116] The copolymeric polycarbonate resin extracted from the horizontal stirred reactor was supplied in a molten state to a vented twin-screw extruder 22a (manufactured by The Japan Steel Works, Ltd., model "TEX30α"). The extruder had three vacuum vents, through which residual low-molecular-weight components in the resin were removed by volatilization. Phosphonic acid was added as a catalyst deactivator just before the first vent (0.64 ppm by weight per 100 parts by weight of copolymerized polycarbonate resin). Irganox 1010, AS2112, SEESORB 709, and E-275 were added just before the third vent (1000 ppm by weight, 500 ppm by weight, 200 ppm by weight, and 3000 ppm by weight per 100 parts by weight of copolymerized polycarbonate resin). The copolymerized polycarbonate resin that had passed through the extruder was passed through a 10-μm Ultipleat candle filter (PALL) while still in the molten state to remove foreign matter. Thereafter, the copolymer polycarbonate resin was extruded in the form of strands from the die, cooled with water, solidified, and then cut into pellets with a rotary cutter to obtain a copolymer polycarbonate resin (PC-1).

[0117] <Process (B-1): Change of raw materials> Following the step (A-1), a step (B-1) of changing the raw material was carried out. That is, without stopping the operation of the step (A-1), the feed ratio of each raw material was changed so that the mass ratio and molar ratio of each structural unit in the resulting copolymeric polycarbonate resin would be as follows. Molar ratio: ISB:CHDM:DPC = 0.500:0.500:1.010 Mass ratio…ISB:CHDM:DPC=42.1:41.5:16.4

[0118] <Step (C-1): Production of Polycarbonate Resin (PC-2)> Following the step (B-1), polymerization of a copolymeric polycarbonate resin was carried out in the same manner as in the step (A-1), except that the total feed ratio was kept at the ratio after changing in the above-mentioned step (B-1) and the reduced viscosity of the resulting copolymeric polycarbonate resin was adjusted to 0.49 to 0.53 dL / g, thereby obtaining a copolymeric polycarbonate resin (PC-2). 1 H-NMR analysis and characterization confirmed that the molar ratio of structural units derived from ISB and CHDM in the resulting resin (PC-2) was 50:50. Thereafter, pelletization of PC-2 was initiated, and pellet samples were taken immediately after the start of pelletization, and 2 and 4 hours later. Equal amounts of the pellets taken at each time were mixed together to form a sample, which was then used to measure and evaluate the number of foreign particles in the film and the number of foreign particles on the plate.

[0119] [Example 2] <Step (A-2): Production of Polycarbonate Resin (PC-3)> A polycarbonate resin (PC-3) was produced in the same manner as in the step (A-1) except that the feed ratio of each raw material was adjusted so that the mass ratio and molar ratio of each structural unit in the resulting copolymeric polycarbonate resin would be as follows, and the reduced viscosity of the resulting copolymeric polycarbonate resin was adjusted to 0.49 to 0.53 dL / g. Molar ratio: ISB:CHDM:DPC = 0.500:0.500:1.010 Mass ratio…ISB:CHDM:DPC=42.1:41.5:16.4

[0120] <Process (B-2)> Following the step (A-2), a step (B-2) of changing the raw material was carried out. That is, without stopping the operation of the step (A-2), the feed ratio of each raw material was changed so that the mass ratio and molar ratio of each structural unit in the resulting copolymeric polycarbonate resin would be as follows. Molar ratio: ISB:CHDM:DPC = 0.700:0.300:1.010 Mass ratio…ISB:CHDM:DPC=58.8:24.9:16.3

[0121] <Process (C-3)> Following the step (B-2), a polycarbonate resin (PC-4) was produced in the same manner as in the step (A-2), except that the total feed ratio was kept at the ratio after changing in the above step (B-2) and the reduced viscosity of the resulting copolymer polycarbonate resin was adjusted to 0.41 to 0.45 dL / g. 1 H-NMR analysis and characterization confirmed that the molar ratio of structural units derived from ISB and CHDM in the resulting resin (PC-4) was 70:30. Thereafter, pelletization of PC-4 was initiated, and pellet samples were taken immediately after the start of pelletization, and 2 and 4 hours later. Equal amounts of the pellets taken at each time were mixed together to form a sample, which was then used to measure and evaluate the number of foreign particles in the film and the number of foreign particles on the plate.

[0122] [Comparative Example 1] A polycarbonate resin (PC-5) was produced in the same manner as in step (A-2).

[0123] Comparative Example 2 A polycarbonate resin (PC-6) was produced in the same manner as in step (A-1).

[0124] [Table 2]

[0125] As shown in Table 2, the polycarbonate resins PC-2 and PC-4 in the examples contained little foreign matter, and it was found that by switching to the production of a different resin without a cleaning process, a resin with little foreign matter could be produced even in the early stages of production of the different resin. In contrast to this, in Comparative Examples 1 and 2 in which resin production was carried out after cleaning the polymerization equipment, it was found that the number of foreign matters increased in the early stage immediately after production.

[0126] As described above, according to the present invention, when two different types of resins are produced, a thermoplastic resin with little foreign matter can be stably produced even in the early stages of production of the other resin. [Explanation of symbols]

[0127] 2a:ISB flexible container 2b:ISB dissolution tank 2c:ISB storage tank 2d:ISB metering pump 3b: Melting DPC tank 3c: DPC metering pump 3d:DPC raw material dissolution tank 3e: Transfer pump 3f:DPC storage tank 3g: DPC metering pump 4a: Static mixer 4b: Filter 4c: Catalyst aqueous solution tank 4d: Catalyst aqueous solution metering pump 5a: CHDM storage tank 5b: CHDM metering pump 21a: First vertical stirred reactor 21b: Reflux condenser 21c: Second vertical stirred reactor 21d: Reflux condenser 21e: Third vertical stirred reactor 21f: Gear pump 21g: Fourth horizontal stirred reactor 21h: Gear pump 22a: Vacuum vent type twin screw extruder 22b: Gear pump 22c: Polymer filter 22d: Dice 23a: Distillate recovery tank 23b: Distillate metering pump 23c: First distillation column 23d: Metering pump 23e: Reflux condenser 23f: Second distillation tower 23g: Metering pump 23h: Reflux condenser

Claims

1. 1. A method for producing a first thermoplastic resin and a second thermoplastic resin that are different from each other, comprising: The first thermoplastic resin and the second thermoplastic resin each contain a structural unit represented by the following formula (1) and a carbonate bond, The method includes, as step (A), a step of supplying at least two or more raw materials to a reactor and causing a polymerization reaction in the reactor to produce the first thermoplastic resin, The method includes a step (B) after the step (A) of changing the feed ratio of the raw materials, Further, after the step (B), a step (C) of producing the second thermoplastic resin is included, The method does not include a step of cleaning the inside of the reactor between the step (A) and the step (B). Method for producing thermoplastic resins. 【Chemistry 1】

2. the raw materials of the first thermoplastic resin and the second thermoplastic resin each contain two common types of monomers; the two common monomers are monomer (a) and monomer (b), When the sum of the molar ratios of the structural units derived from the monomer (a) and the structural units derived from the monomer (b) contained in the first thermoplastic resin or the second thermoplastic resin is taken as 100 mol %, the molar ratio occupied by the structural units derived from the monomer (a) is taken as X (mol %), The method for producing a thermoplastic resin according to claim 1 , wherein the X (mol %) differs by 1 or more between the first thermoplastic resin and the second thermoplastic resin.

3. The method for producing a thermoplastic resin according to claim 2, wherein the difference in X (mol%) between the first thermoplastic resin and the second thermoplastic resin is 10 or more.

4. Using at least a first reactor and a second reactor, connecting the first reactor and the second reactor; supplying two or more raw material monomers to the first reactor; transferring at least a portion of the product produced in the first reactor to the second reactor, and causing a further polymerization reaction in the second reactor; The method of claim 1.

5. The manufacturing method according to claim 1 , wherein the glass transition temperatures of the first thermoplastic resin and the second thermoplastic resin differ by 5° C. or more.

6. The method according to claim 2 , wherein the structural unit derived from the monomer (a) is a structural unit represented by the formula (1).

7. the first thermoplastic resin and the second thermoplastic resin are polycarbonate resins; raw materials for the first thermoplastic resin and the second thermoplastic resin contain one or more dihydroxy compounds and one or more carbonate diesters; At least one step of carrying out a melt polycondensation reaction, A method for producing the thermoplastic resin according to claim 1.

8. The thermoplastic resin contains a structural unit represented by the following formula (1): ２ A thermoplastic resin film having 100 or less foreign particles of 25 μm or more per film. 【Chemistry 2】

9. 1. A method for producing two different thermoplastic resins, comprising: The method includes, as step (A), a step of supplying at least two or more raw materials to a reactor and causing a polymerization reaction in the reactor to produce a first thermoplastic resin, The method includes a step (B) after the step (A) of changing the feed ratio of the raw materials, Further, after the step (B), a step (C) is included in which a second thermoplastic resin different from the first thermoplastic resin is produced, The method does not include a step of cleaning the inside of the reactor between the step (A) and the step (B). Method for producing thermoplastic resins.

Images