JP2024060758A - Resin composition and method for producing resin composition - Google Patents

Abstract

[Problem] To provide a resin composition containing an acrylic resin and a polycarbonate resin and having excellent transparency. [Solution] A resin composition obtained by kneading an acrylic resin and a polycarbonate resin having a structural unit derived from a compound represented by formula (1), the polycarbonate resin and the acrylic resin being kneaded using a kneader equipped with a disk-shaped segment 22 having a plurality of shaft-penetrating portions 222 through which the rotating shaft of the kneader rotatably passes and a plurality of small holes 221a formed around the plurality of shaft-penetrating portions 222 and serving as a flow path for the kneading material. [Chemical formula 1] TIFF2024060758000012.tif31170 [Selected figure] Figure 1

Description

The present invention relates to a resin composition and a method for producing a resin composition.

Polycarbonate resin is generally manufactured using raw materials derived from petroleum resources. However, in recent years, there have been concerns about the depletion of petroleum resources, and there is a demand for polycarbonate resins made from raw materials obtained from biomass resources such as plants. In addition, there are concerns that global warming due to the increase and accumulation of carbon dioxide emissions will lead to climate change, so there is a demand for the development of polycarbonate resins made from plant-derived monomers that are carbon neutral even when disposed of after use.

For example, it has been proposed to use isosorbide (ISB) as a plant-derived monomer and obtain a polycarbonate resin by transesterification with diphenyl carbonate. It has been shown that polycarbonate resins obtained from dihydroxy compounds such as isosorbide not only have excellent optical properties, but also have extremely excellent weather resistance and surface hardness compared to the aromatic polycarbonate resins that have been widely used up to now (Patent Document 1).

Acrylic resin is also excellent in transparency, weather resistance, high elasticity, and surface hardness, and it is expected that new polymer alloys will be developed by mixing these two types of transparent resins. However, there are concerns that phase separation due to shear heat will occur in the shear flow caused by a kneading machine equipped with a kneading disk. Therefore, a method has been proposed that utilizes extensional flow using blister disks as a method for mixing different resins without shear heat generation (Patent Document 2).

GB 1079686 International Publication No. 2018/155502

According to the inventors' research, there was a problem that kneading polycarbonate resin and acrylic resin in a kneading machine equipped with a kneading disk resulted in a resin composition that lost transparency.

Therefore, the present inventors have found that a resin composition having excellent transparency can be obtained by kneading a polycarbonate resin and an acrylic resin in a kneader equipped with a blister disk as described in Patent Document 2.
An object of the present invention is to provide a resin composition which contains an acrylic resin and a polycarbonate resin and has excellent transparency.

［２］ 前記ポリカーボネート樹脂と前記アクリル樹脂の質量比が、前記ポリカーボネート樹脂：前記アクリル樹脂＝９０：１０～１０：９０である、［１］に記載の樹脂組成物。
［３］ 式（１）で表される化合物に由来する構成単位を有するポリカーボネート樹脂とアクリル樹脂を混練する樹脂組成物の製造方法であって、
前記ポリカーボネート樹脂と前記アクリル樹脂を、混練機の回転軸が回転自在に貫通する軸貫通部と、前記軸貫通部の周囲に穿設された混練材料の流路となる複数の小孔とを有するディスク型セグメントを備える混練機を用いて混練する、樹脂組成物の製造方法。

［４］ ２００～２４０℃の温度で混練する、［３］に記載の樹脂組成物の製造方法。
［５］ 混練時の圧力損失が１～２０ＭＰａである、［３］又は［４］に記載の樹脂組成物の製造方法。 The present invention has the following aspects.
[1] A resin composition obtained by kneading a polycarbonate resin having a structural unit derived from a compound represented by formula (1) and an acrylic resin,
A resin composition obtained by kneading the polycarbonate resin and the acrylic resin using a kneader equipped with a disk-shaped segment having a shaft penetrating portion through which the rotating shaft of the kneader passes freely to allow free rotation, and a plurality of small holes formed around the shaft penetrating portion to serve as a flow path for the material to be kneaded.

[2] The resin composition according to [1], wherein the mass ratio of the polycarbonate resin to the acrylic resin is 90:10 to 10:90.
[3] A method for producing a resin composition by kneading a polycarbonate resin having a structural unit derived from a compound represented by formula (1) with an acrylic resin, comprising the steps of:
The polycarbonate resin and the acrylic resin are kneaded using a kneader equipped with a disk-shaped segment having a shaft penetrating portion through which a rotating shaft of the kneader passes to be able to rotate freely, and a plurality of small holes that serve as a flow path for the kneading material, which are drilled around the shaft penetrating portion.

[4] The method for producing the resin composition according to [3], wherein the mixture is kneaded at a temperature of 200 to 240° C.
[5] The method for producing a resin composition according to [3] or [4], wherein the pressure loss during kneading is 1 to 20 MPa.

The present invention provides a resin composition that contains acrylic resin and polycarbonate resin and has excellent transparency.

FIG. 2 is a front view showing one embodiment of a disk-type segment of a kneader.

Hereinafter, an embodiment of the present invention will be described in detail, but the present invention is not limited to the embodiment described below, and can be modified and implemented as desired without departing from the gist of the present invention.
In the following, a monomer component before polymerization is referred to as "monomer" and may be abbreviated to "monomer". A structural unit constituting a polymer may be referred to as "monomer unit". (Meth)acrylate refers to methacrylate and/or acrylate.
Furthermore, the use of "to" to indicate a range of values means that the values before and after it are included as the lower and upper limits.

[Resin composition]
The resin composition of the present invention is a resin composition obtained by kneading a polycarbonate resin having a structural unit derived from a specific dihydroxy compound (hereinafter also referred to as "polycarbonate resin (A)") and an acrylic resin (hereinafter also referred to as "acrylic resin (B)") using a kneader.

<Polycarbonate resin (A)>
The polycarbonate resin (A) has a structural unit (hereinafter also referred to as "structural unit (1)") derived from a dihydroxy compound represented by formula (1) (hereinafter also referred to as "dihydroxy compound (1)"). The structural unit (1) constituting the polycarbonate resin (A) of the present embodiment is obtained by removing a hydrogen atom from a hydroxy group of the dihydroxy compound (1).

Polycarbonate resin (A) is a polycarbonate resin in which structural units derived from dihydroxy compounds are linked by carbonate bonds.

(Structural unit derived from dihydroxy compound)
The polycarbonate resin (A) may contain a structural unit (1) derived from a dihydroxy compound (1) as a structural unit derived from a dihydroxy compound, and may contain a structural unit derived from a dihydroxy compound other than the dihydroxy compound (1). That is, the polycarbonate compound (A) may be a homopolycarbonate resin having only the structural unit (1) derived from the dihydroxy compound (1) as a structural unit derived from the dihydroxy compound, or may be a copolymer polycarbonate resin having the structural unit (1) derived from the dihydroxy compound (1) and a structural unit (hereinafter also referred to as "structural unit (a)") derived from a dihydroxy compound other than the dihydroxy compound (1) as a structural unit derived from the dihydroxy compound (1). As the polycarbonate compound (A), a copolymer polycarbonate resin is preferable from the viewpoint of being more excellent in impact resistance.

Examples of the dihydroxy compound (1) include isosorbide (abbreviation: ISB, also known as 1,4:3,6-dianhydroglucitol), isomannide (also known as 1,4:3,6-dianhydromannitol), and isoidide (also known as 1,4:3,6-dianhydroiditol), which are stereoisomers.
The hydroxy compound (1) can be used alone or in combination of two or more kinds.

Among the dihydroxy compounds (1), isosorbide (ISB), which is obtained by dehydration and condensation of sorbitol (also known as glucitol), which is produced from various starches that are abundant and readily available as a plant-derived resource, is preferred in terms of availability and ease of production, weather resistance, optical properties, moldability, heat resistance, and carbon neutrality.

The dihydroxy compound (1) is easily oxidized gradually by oxygen. Therefore, when handling during storage or production, in order to prevent decomposition by oxygen, it is preferable to avoid the inclusion of moisture, use an oxygen scavenger, or store under a nitrogen atmosphere.

The polycarbonate resin (A) is preferably a copolymeric polycarbonate resin having a structural unit (1) derived from a dihydroxy compound (1) and a structural unit (a) derived from a dihydroxy compound (a) (referring to a dihydroxy compound other than the dihydroxy compound (1)).
The dihydroxy compound (a) is not particularly limited, but is preferably one or more dihydroxy compounds selected from the group consisting of aliphatic hydrocarbon dihydroxy compounds, alicyclic hydrocarbon dihydroxy compounds, ether-containing dihydroxy compounds, and aromatic group-containing dihydroxy compounds (hereinafter also referred to as "dihydroxy compound (b)"). Hereinafter, the structural unit derived from the dihydroxy compound (b) will be referred to as "structural unit (b)" as appropriate. The dihydroxy compound (b) is preferably one or more dihydroxy compounds selected from the group consisting of aliphatic hydrocarbon dihydroxy compounds, alicyclic hydrocarbon dihydroxy compounds, and ether-containing dihydroxy compounds. These dihydroxy compounds have a flexible molecular structure, so that the impact resistance of the resulting polycarbonate resin can be improved by using these dihydroxy compounds as raw materials. Among them, it is more preferable to use aliphatic hydrocarbon dihydroxy compounds and/or alicyclic hydrocarbon dihydroxy compounds, which have a large effect of improving impact resistance, and it is even more preferable to use alicyclic hydrocarbon dihydroxy compounds. Specific examples of aliphatic hydrocarbon dihydroxy compounds, alicyclic hydrocarbon dihydroxy compounds, ether-containing dihydroxy compounds, and aromatic group-containing dihydroxy compounds are as follows:

Specific examples of the aliphatic hydrocarbon dihydroxy compounds include 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.

Specific examples of the dihydroxy compounds of alicyclic hydrocarbons include dihydroxy compounds which are primary alcohols of alicyclic hydrocarbons, such as dihydroxy compounds derived from terpene compounds, such as 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, tricyclodecane dimethanol, pentacyclopentadecane dimethanol, 2,6-decalin dimethanol, 1,5-decalin dimethanol, 2,3-decalin dimethanol, 2,3-norbornane dimethanol, 2,5-norbornane dimethanol, 1,3-adamantanedimethanol, and limonene; and dihydroxy compounds which are secondary or tertiary alcohols of alicyclic hydrocarbons, such as 1,2-cyclohexanediol, 1,4-cyclohexanediol, 1,3-adamantanediol, hydrogenated bisphenol A, and 2,2,4,4-tetramethyl-1,3-cyclobutanediol.

Specific examples of the ether-containing dihydroxy compound include oxyalkylene glycols and dihydroxy compounds containing an acetal ring.
Specific examples of the oxyalkylene glycols include diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol and polypropylene glycol.
Specific examples of the dihydroxy compound containing an acetal ring include spiro glycol represented by formula (2) and dioxane glycol represented by formula (3).

Specific examples of dihydroxy compounds containing the aromatic group include 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 aromatic bisphenol compounds such as bis(4-hydroxyphenyl)-2-ethylhexane, 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, 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; and

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-hydroxypropoxy)-3-methylphenyl)fluorene, 9,9-bis(4-(2-hydroxyethoxy)-3-isopropylphenyl)fluorene, 9,9-bis(4-(2-hydroxyethoxy)-3-isobutylphenyl)fluorene, 9,9 -bis(4-(2-hydroxyethoxy)-3-tert-butylphenyl)fluorene, 9,9-bis(4-(2-hydroxyethoxy)-3-cyclohexylphenyl)fluorene, 9,9-bis(4-(2-hydroxyethoxy)-3-phenylphenyl)fluorene, 9,9-bis(4-(2-hydroxyethoxy)-3,5-dimethylphenyl)fluorene, 9,9-bis(4-(2-hydroxyethoxy)-3-tert-butyl-6-methylphenyl)fluorene, and 9,9-bis(4-(3-hydroxy-2,2-dimethylpropoxy)phenyl)fluorene are examples of dihydroxy compounds having a fluorene ring.

As the dihydroxy compound containing an aromatic group, it is also possible to use dihydroxy compounds other than those mentioned above.

In the polycarbonate resin (A), the content ratio of the structural unit (1) relative to 100 mol% of all structural units derived from dihydroxy compounds is not particularly limited, but the lower limit is preferably 30 mol% or more, more preferably 40 mol% or more, even more preferably 50 mol% or more, particularly preferably 55 mol% or more, and most preferably 60 mol% or more. The upper limit is more preferably 95 mol% or less, even more preferably 90 mol% or less, and even more preferably 85 mol% or less. In these cases, the content of the biological substance can be further increased, and the heat resistance can be further improved. The content ratio of the structural unit (1) in the polycarbonate resin (A) may be 100 mol%, but from the viewpoint of further increasing the molecular weight and further improving the impact resistance, it is preferable to have a structural unit other than the structural unit (1).

In the case where the polycarbonate resin (A) is a copolymer polycarbonate having the structural unit (b) in addition to the structural unit (1), the content ratio of the structural unit (b) is not particularly limited, but the lower limit is preferably 5 mol% or more, more preferably 10 mol% or more, and even more preferably 15 mol% or more. The upper limit is preferably 70 mol% or less, more preferably 60 mol% or less, even more preferably 50 mol% or less, particularly preferably 45 mol% or less, and most preferably 40 mol% or less. In these cases, a flexible structure is introduced into the polymer chain, so that the toughness of the resin can be further increased and the impact resistance can be further improved.

In addition to the structural unit (1) derived from dihydroxy compound (1) and the structural unit (b) derived from dihydroxy compound (b), polycarbonate resin (A) may further have a structural unit (hereinafter also referred to as "structural unit (c)") derived from a dihydroxy compound other than dihydroxy compound (1) and dihydroxy compound (b) (hereinafter also referred to as "dihydroxy compound (c)"). However, in order for the present invention to have a good effect, the content ratio of structural unit (c) is preferably 10 mol% or less, more preferably 5 mol% or less, relative to 100 mol% of all structural units derived from dihydroxy compounds.

The dihydroxy compound (c) can be appropriately selected depending on the properties required for the polycarbonate resin.
The dihydroxy compound (c) may be used alone or in combination of two or more kinds.
By using the dihydroxy compound (c) in combination with the dihydroxy compound (1), it is possible to obtain effects such as improvements in flexibility, mechanical properties, and moldability of the polycarbonate resin (A).

The dihydroxy compound used as a raw material for polycarbonate resin (A) may contain a stabilizer such as a reducing agent, an antioxidant, an oxygen scavenger, a light stabilizer, an antacid, a pH stabilizer, or a heat stabilizer. In particular, dihydroxy compound (1) has a property of being easily altered under acidic conditions. Therefore, by using a basic stabilizer in the synthesis process of polycarbonate resin (A), the alteration of dihydroxy compound (1) can be suppressed, and the quality of the obtained polycarbonate resin (A) and the resin composition of the present invention can be further improved.

(Carbonate bond)
The polycarbonate resin (A) contains a carbonate bond that connects the structural units derived from a dihydroxy compound. The carbonate bond is a bond derived from a carbonic acid diester.

The carbonic acid diester may be a compound represented by formula (4) (hereinafter, also referred to as "carbonic acid diester compound (4)").
The carbonate diester compound (4) can be used alone or in combination of two or more.

In formula (4), A ¹ and A ² are each independently a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 18 carbon atoms or a substituted or unsubstituted aromatic hydrocarbon group, and A ¹ and A ² may be the same or different. As A ¹ and A ² , it is preferable to adopt a substituted or unsubstituted aromatic hydrocarbon group, and it is more preferable to adopt an unsubstituted aromatic hydrocarbon group.

Specific examples of the carbonate diester compound (4) include diphenyl carbonate (DPC) and substituted diphenyl carbonates such as ditolyl carbonate, dimethyl carbonate, diethyl carbonate, and di-tert-butyl carbonate. As the carbonate diester compound (4), it is preferable to use diphenyl carbonate or ditolyl carbonate, and it is more preferable to use diphenyl carbonate. Note that the carbonate diester may contain impurities such as chloride ions, which may inhibit the polycondensation reaction or deteriorate the color tone of the resulting polycarbonate resin, so it is preferable to use a compound purified by distillation or the like, as necessary.

(Production method of polycarbonate resin (A))
The method for producing the polycarbonate resin (A) is not particularly limited, and any method may be adopted using a dihydroxy compound and a carbonic acid diester as appropriate, such as an interfacial polymerization method, a melt transesterification method, a pyridine method, a ring-opening polymerization method of a cyclic carbonate compound, or a solid-phase transesterification method of a prepolymer.

For example, polycarbonate resin (A) can be synthesized by polycondensing the above-mentioned dihydroxy compound and carbonic acid diester through an ester exchange reaction. More specifically, it can be obtained by removing the monohydroxy compound and the like that are by-produced in the ester exchange reaction from the system during the polycondensation.

The transesterification reaction proceeds in the presence of a transesterification catalyst (hereinafter, the transesterification catalyst is referred to as a "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.

The polymerization catalyst is not limited as long as it satisfies the transparency, color tone, heat resistance, weather resistance, and mechanical strength of the resulting polycarbonate resin (A). For example, metal compounds of Group I or II (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 can be used as the polymerization catalyst. Among these, Group 1 metal compounds and/or Group 2 metal compounds are preferred, with Group 2 metal compounds being more preferred.

The Group 1 metal compounds and/or Group 2 metal compounds are usually used in the form of hydroxides or salts such as carbonates, carboxylates, and phenolates. Hydroxides, carbonates, and acetates are preferred in terms of availability and ease of handling, and acetates are preferred in terms of color and polymerization activity.

Examples of Group 1 metal compounds include sodium hydroxide, potassium hydroxide, lithium hydroxide, cesium hydroxide, sodium hydrogen carbonate, potassium hydrogen carbonate, lithium hydrogen carbonate, cesium hydrogen carbonate, sodium carbonate, potassium carbonate, lithium carbonate, cesium carbonate, sodium acetate, potassium acetate, lithium acetate, cesium acetate, sodium stearate, potassium stearate, lithium stearate, cesium stearate, sodium borohydride, potassium borohydride, lithium borohydride, cesium borohydride, sodium phenyl borohydride, potassium phenyl borohydride, lithium phenyl borohydride, cesium phenyl borohydride, sodium benzoate, potassium benzoate, lithium benzoate, cesium benzoate, disodium hydrogen phosphate, dipotassium hydrogen phosphate, dilithium hydrogen phosphate, dicesium hydrogen phosphate, disodium phenylphosphate, dipotassium phenylphosphate, dilithium phenylphosphate, and dicesium phenylphosphate. Examples of sodium, potassium, lithium, and cesium alcoholates and phenolates are also included. Further examples include disodium salt, dipotassium salt, dilithium salt, and dicesium salt of bisphenol A. Among these examples, cesium compounds and lithium compounds are preferred.

Examples of Group 2 metal compounds include calcium hydroxide, barium hydroxide, magnesium hydroxide, strontium hydroxide, calcium hydrogen carbonate, barium hydrogen carbonate, magnesium hydrogen carbonate, strontium hydrogen carbonate, calcium carbonate, barium carbonate, magnesium carbonate, strontium carbonate, calcium acetate, barium acetate, magnesium acetate, strontium acetate, calcium stearate, barium stearate, magnesium stearate, strontium stearate, etc. Among these examples, magnesium compounds, calcium compounds, and barium compounds are preferred, and at least one of magnesium compounds and calcium compounds is more preferred.

Although it is possible to use auxiliary basic compounds such as basic boron compounds, basic phosphorus compounds, basic ammonium compounds, and amine compounds in combination with the Group 1 metal compounds and/or Group 2 metal compounds, it is particularly preferable to use only the Group 1 metal compounds and/or Group 2 metal compounds.

Specific examples of the basic boron compound include tetramethyl boron, tetraethyl boron, tetrapropyl boron, tetrabutyl boron, trimethylethyl boron, trimethylbenzyl boron, trimethylphenyl boron, triethylmethyl boron, triethylbenzyl boron, triethylphenyl boron, tributylbenzyl boron, tributylphenyl boron, tetraphenyl boron, benzyltriphenyl boron, and methyltriphenyl boron. In addition, sodium salts, potassium salts, lithium salts, calcium salts, barium salts, magnesium salts, and strontium salts of butyltriphenyl boron and the like are also included.

Specific examples of the basic phosphorus compound include triethylphosphine, tri-n-propylphosphine, triisopropylphosphine, tri-n-butylphosphine, triphenylphosphine, tributylphosphine, and quaternary phosphonium salts.

Specific examples of the basic ammonium compound 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.

Specific examples of the amine compounds include 4-aminopyridine, 2-aminopyridine, N,N-dimethyl-4-aminopyridine, 4-diethylaminopyridine, 2-hydroxypyridine, 2-methoxypyridine, 4-methoxypyridine, 2-dimethylaminoimidazole, 2-methoxyimidazole, imidazole, 2-mercaptoimidazole, 2-methylimidazole, and aminoquinoline.

As the polymerization catalyst, at least one metal compound selected from the group consisting of Group 2 metal compounds is preferred. In this case, various physical properties such as transparency, hue, and weather resistance of the polycarbonate resin (A) can be further improved. From the viewpoint of further enhancing this effect, the catalyst is more preferably composed of at least one metal compound selected from the group consisting of magnesium compounds, calcium compounds, and barium compounds, and even more preferably composed of at least one metal compound selected from the group consisting of magnesium compounds and calcium compounds.

The amount of the polymerization catalyst used is preferably 0.1 to 300 μmol, more preferably 0.5 to 100 μmol, and even more preferably 1 to 50 μmol, per mol of the total dihydroxy compounds to be subjected to the reaction.
When the polymerization catalyst is at least one selected from Group 1 metal compounds and Group 2 metal compounds, the amount of the polymerization catalyst used is preferably 0.1 to 300 μmol, more preferably 0.1 to 100 μmol, even more preferably 0.5 to 50 μmol, and still more preferably 1 to 25 μmol, calculated as the metal amount per 1 mol of the total dihydroxy compounds to be subjected to the reaction.
When a compound containing at least one metal selected from the group consisting of Group 2 metals is used as the polymerization catalyst, the amount of the Group 2 metal compound used is preferably 0.1 to 20 μmol, more preferably 0.5 to 10 μmol, and even more preferably 0.7 to 3 μmol, calculated as the metal amount, per 1 mol of the total dihydroxy compounds to be subjected to the reaction.

Considering the adverse effects of sodium, potassium, or cesium among the group 1 metals on the color tone of the polycarbonate resin, and the adverse effects of iron on the color tone of the polycarbonate resin, it is preferable that the total content of sodium, potassium, cesium, and iron in the polycarbonate resin (A) is 1 mass ppm or less. In this case, the deterioration of the color tone of the polycarbonate resin can be further prevented, and the color tone of the polycarbonate resin can be made even better. From the same point of view, it is more preferable that the total content of sodium, potassium, cesium, and iron in the polycarbonate resin is 0.5 mass ppm or less. Note that these metals may be mixed in not only from the catalyst used, but also from the raw materials or the reaction apparatus. Regardless of the source, the total amount of compounds of these metals in the polycarbonate resin is preferably in the above-mentioned range as the total content of sodium, potassium, cesium, and iron.

By adjusting the amount of polymerization catalyst used within the above range, the polymerization rate can be increased, making it possible to obtain polycarbonate resin (A) of the desired molecular weight without necessarily increasing the polymerization temperature, and therefore deterioration of the color tone of polycarbonate resin (A) can be suppressed. In addition, it is possible to prevent unreacted raw materials from volatilizing during the polymerization, which would cause the molar ratio of dihydroxy compound and carbonic acid diester to collapse, so that polycarbonate resin (A) of the desired molecular weight can be obtained more reliably. Furthermore, it is possible to suppress the occurrence of side reactions, so it is possible to further prevent deterioration of the color tone of polycarbonate resin (A) or coloring during molding processing.

The polycarbonate resin (A) is produced by melt-polymerizing a dihydroxy compound including the dihydroxy compound (1) and a carbonic acid diester through an ester exchange reaction. It is preferable to mix the raw materials, the dihydroxy compound and the carbonic acid diester, uniformly before the ester exchange reaction.

The lower limit of the mixing temperature is usually 80°C or higher, and preferably 90°C or higher. The upper limit of the mixing temperature is usually 250°C or lower, preferably 200°C or lower, and more preferably 150°C or lower. The mixing temperature range is preferably 100 to 120°C. If the mixing temperature is too low, the dissolution rate may be slow or the solubility may be insufficient, often resulting in problems such as solidification, and if the mixing temperature is too high, it may result in thermal degradation of the dihydroxy compound, which may result in a deterioration in the hue of the obtained polycarbonate resin (A) and a negative effect on the light resistance.

In addition, the operation of mixing the dihydroxy compound and the carbonic acid diester is preferably carried out in an atmosphere with an oxygen concentration of 10% by volume or less, more preferably in an atmosphere with an oxygen concentration of 0.0001 to 10% by volume, even more preferably in an atmosphere with an oxygen concentration of 0.0001 to 5% by volume, and even more preferably in an atmosphere with an oxygen concentration of 0.0001 to 1% by volume, in order to prevent deterioration of the hue of the resulting polycarbonate resin (A).

The polycarbonate resin (A) is preferably produced by melt polymerization in multiple stages using a catalyst in multiple reactors. The reason for carrying out melt polymerization in multiple reactors is that in the early stages of the melt polymerization reaction, since the reaction liquid contains a large amount of monomers, it is important to suppress the evaporation of the monomers while maintaining the required polymerization rate, and in the later stages of the melt polymerization reaction, it is important to sufficiently distill off the by-product monohydroxy compound in order to shift the equilibrium to the polymerization side. In this way, in order to set different polymerization reaction conditions, it is preferable to use multiple reactors arranged in series from the viewpoint of production efficiency. As described above, the number of the reactors may be at least two or more, but from the viewpoint of production efficiency, it is preferable to use three or more, more preferably three to five, and even more preferably four.

The reaction may be carried out in a batch or continuous manner, or in a combination of a batch and continuous manner. Furthermore, in order to suppress the amount of monomer distilled off, it is effective to use a reflux condenser in the polymerization reactor, and this is particularly effective in a reactor in the early stages of polymerization where there is a large amount of unreacted monomer components. The temperature of the refrigerant introduced into the reflux condenser can be appropriately selected depending on the monomer used, but the temperature of the refrigerant introduced into the reflux condenser is usually 45 to 180°C at the inlet of the reflux condenser, preferably 80 to 150°C, and more preferably 100 to 130°C. If the temperature of the refrigerant introduced into the reflux condenser is too high, the reflux amount decreases and its effect decreases, and if it is too low, the efficiency of distilling off the monohydroxy compound that should be distilled off tends to decrease. As the refrigerant, hot water, steam, heat transfer oil, etc. are used, and steam and heat transfer oil are preferred.

In order to maintain an appropriate polymerization rate and suppress distillation of monomers while not impairing the hue, thermal stability, light resistance, etc. of the polycarbonate resin (A) finally obtained, it is preferable to appropriately select the type and amount of the polymerization catalyst. In producing polycarbonate resin (A), if there are two or more reactors, the reactors may have multiple reaction stages with different conditions, the temperature and pressure may be changed continuously, etc.

In the production of the polycarbonate resin (A), the polymerization catalyst can be added to a raw material preparation tank or a raw material storage tank, or can be added directly to the reactor. From the viewpoints of supply stability and control of melt polymerization, however, it is preferable to install a catalyst supply line in the raw material line prior to supply to the reactor and supply the catalyst in the form of an aqueous solution.
As polymerization conditions, it is preferable to obtain a prepolymer at a relatively low temperature and low vacuum in the early stage of polymerization, and to increase the molecular weight to a predetermined value at a relatively high temperature and high vacuum in the later stage of polymerization, but it is preferable to appropriately select the jacket temperature, the internal temperature, and the pressure in the reaction system at each molecular weight stage from the viewpoint of the hue and light resistance of the obtained polycarbonate resin (A). For example, if either the temperature or the pressure is changed too quickly before the polymerization reaction reaches a predetermined value, unreacted monomers are distilled out, which upsets the molar ratio of the dihydroxy compound and the carbonic acid diester, leading to a decrease in the polymerization rate or failure to obtain a polymer having a predetermined molecular weight or terminal group, and as a result, it is possible that the object of the present invention cannot be achieved.

If the temperature of the transesterification reaction is too low, it may lead to a decrease in productivity and an increase in the heat history of the product, and if it is too high, it may not only lead to the volatilization of the monomer, but also promote the decomposition and coloring of the polycarbonate resin (A). In the production of polycarbonate resin (A), the method of transesterifying a dihydroxy compound including dihydroxy compound (1) with a carbonic acid diester in the presence of a catalyst is usually carried out in a multi-stage process of two or more stages. Specifically, the first stage transesterification reaction temperature (hereinafter sometimes referred to as "internal temperature") is preferably 140°C or higher, more preferably 150°C or higher, even more preferably 180°C or higher, and even more preferably 200°C or higher. In addition, the first stage transesterification reaction temperature is preferably 270°C or lower, more preferably 240°C or lower, even more preferably 230°C or lower, and even more preferably 220°C or lower. The residence time in the first stage transesterification reaction is usually 0.1 to 10 hours, preferably 0.5 to 3 hours, and the first stage transesterification reaction is carried out while distilling off the generated monohydroxy compound outside the reaction system. From the second stage onwards, the transesterification reaction temperature is increased, and the transesterification reaction is usually carried out at a temperature of 210 to 270°C, preferably 220 to 250°C, and while simultaneously removing the generated monohydroxy compound outside the reaction system, the pressure of the reaction system is gradually lowered from the pressure of the first stage, and the polycondensation reaction is carried out for usually 0.1 to 10 hours, preferably 0.5 to 6 hours, more preferably 1 to 3 hours, so that the pressure of the reaction system is finally 200 Pa or less.

If the ester exchange reaction temperature is too high, the color of the molded product may deteriorate and it may be prone to brittle fracture. If the ester exchange reaction temperature is too low, the target molecular weight may not increase and the molecular weight distribution may become broad, resulting in poor impact strength. If the residence time for the ester exchange reaction is too long, it may be prone to brittle fracture. If the residence time is too short, the target molecular weight may not increase and the impact strength may be poor.

From the viewpoint of effective resource utilization, it is preferable to reuse the by-product monohydroxy compound as a raw material for carbonate diesters or various bisphenol compounds after purifying it as necessary. In particular, in order to suppress coloration, thermal deterioration, or discoloration of polycarbonate resin (A) and obtain a good polycarbonate resin (A) with high impact strength, the maximum temperature inside the reactor in all reaction stages is preferably less than 255°C, more preferably 250°C or less, and even more preferably 225 to 245°C. In addition, in order to suppress a decrease in the polymerization rate in the latter half of the polymerization reaction and to minimize the thermal deterioration of polycarbonate resin (A) due to thermal history, it is preferable to use a horizontal reactor with excellent plug flow properties and interface renewal properties in the final stage of the reaction.

In addition, in order to obtain a polycarbonate resin (A) with high impact strength and a high molecular weight, the polymerization temperature may be increased as much as possible and the polymerization time may be extended. In this case, however, foreign matter and discoloration may occur in the polycarbonate resin (A), which may lead to brittle fracture. Therefore, in order to satisfy both the need to increase impact strength and to reduce brittle fracture, it is preferable to keep the polymerization temperature low, use a highly active catalyst to shorten the polymerization time, and adjust the pressure of the reaction system appropriately. Furthermore, in order to reduce brittle fracture, it is also preferable to remove foreign matter and discoloration generated in the reaction system using a filter or the like during the reaction or at the final stage of the reaction.

In addition, when polycarbonate resin (A) is produced using a substituted diphenyl carbonate such as diphenyl carbonate or ditolyl carbonate as the carbonate diester represented by formula (4), it is inevitable that phenol and substituted phenol are by-produced and remain in polycarbonate resin (A). However, since phenol and substituted phenol also have aromatic rings, they absorb ultraviolet light and may cause deterioration of light resistance, as well as odor during molding. After a normal batch reaction, polycarbonate resin (A) contains 1000 mass ppm or more of aromatic monohydroxy compounds having aromatic rings such as by-produced phenols. From the viewpoint of light resistance and odor reduction, it is preferable to use a horizontal reactor with excellent volatilization performance or an extruder with a vacuum vent to reduce the content of aromatic monohydroxy compounds in polycarbonate resin (A) to 700 mass ppm or less, more preferably 500 mass ppm or less, and even more preferably 300 mass ppm or less. However, it is difficult to completely remove aromatic monohydroxy compounds industrially, and the lower limit of the content of aromatic monohydroxy compounds in the polycarbonate resin (A) is usually 1 mass ppm. These aromatic monohydroxy compounds may naturally have a substituent depending on the raw material used, and may have, for example, an alkyl group having 5 or less carbon atoms.

Group 1 metals, particularly lithium, sodium, potassium, and cesium, and especially sodium, potassium, and cesium, may be mixed in not only from the catalyst used but also from the raw materials and reaction equipment. If these metals are contained in large amounts in the polycarbonate resin (A), they may adversely affect the hue. Therefore, it is preferable that the total content of these compounds in the polycarbonate resin (A) of the present invention is small, and the amount of metal in the polycarbonate resin (A) is usually 1 ppm by mass or less, preferably 0.8 ppm by mass or less, and more preferably 0.7 ppm by mass or less.

The amount of metal in polycarbonate resin (A) can be measured by various conventional methods, but after recovering the metal in polycarbonate resin (A) by a method such as wet ashing, it can be measured using a method such as atomic emission, atomic absorption, inductively coupled plasma (ICP), etc.

(Glass-transition temperature)
The glass transition temperature of the polycarbonate resin (A) is not particularly limited, but is preferably 90°C or higher. In this case, the heat resistance and impact resistance of the polycarbonate resin composition can be improved in a well-balanced manner. From the same viewpoint, the glass transition temperature of the polycarbonate resin is more preferably 100°C or higher, more preferably 110°C or higher, and even more preferably 120°C or higher. On the other hand, the glass transition temperature of the polycarbonate resin is preferably 250°C or lower, more preferably 200°C or lower, and even more preferably 170°C or lower. In this case, the melt viscosity can be reduced by the above-mentioned melt polymerization, and a polymer with a sufficient molecular weight can be obtained. In addition, when an attempt is made to increase the molecular weight by increasing the polymerization temperature to reduce the melt viscosity, the heat resistance of the component (a) is insufficient, so that the polymer may be easily colored. From the viewpoint of being able to improve the molecular weight and prevent coloring in a well-balanced manner, the glass transition temperature of the polycarbonate resin is more preferably 165°C or lower, more preferably 160°C or lower, and even more preferably 150°C or lower. The glass transition temperature of the polycarbonate resin can be adjusted, for example, by selecting the constituent units of the resin or changing the ratio thereof.
In the present invention, the glass transition temperature is a glass transition temperature measured by a differential scanning calorimetry (DSC) method according to JIS K 7121:1987 "Method for measuring transition temperature of plastics" and JIS K 7121:2012 "Method for measuring transition temperature of plastics (Supplement 1)".

(Refractive Index)
The refractive index of the polycarbonate resin (A) is preferably 1.480 to 1.620, and more preferably 1.490 to 1.600. When the refractive index is within this range, the transparency of the resin composition obtained by kneading with the acrylic resin (B) is superior. The refractive index of the polycarbonate resin (A) can be adjusted, for example, by selecting the structural units of the resin or changing the ratio.
In the present invention, the refractive index is a refractive index obtained by measuring by Method A of JIS K 7142:2014 "Plastics-Determination of refractive index" (a method for measuring the refractive index of a molded product, a cast sheet or an extruded sheet, or a film using a refractometer).

(Molecular Weight)
The molecular weight of the polycarbonate resin (A) can be expressed by reduced viscosity, and the higher the reduced viscosity, the higher the molecular weight. The reduced viscosity is usually 0.30 dL/g or more, and preferably 0.33 dL/g or more. In this case, the mechanical strength of the molded product molded from the resin composition of the present invention can be further improved. On the other hand, the reduced viscosity is usually 1.20 dL/g or less, more preferably 1.00 dL/g or less, and even more preferably 0.80 dL/g or less. In these cases, the flowability during molding of the resin composition of the present invention can be improved, and the productivity and moldability can be further improved.
The reduced viscosity of the polycarbonate resin (A) is a value measured using a solution in which the concentration of the resin composition is precisely adjusted to 0.6 g/dL using methylene chloride as a solvent, with an Ubbelohde viscometer at a temperature of 20.0° C.±0.1° C. The higher the reduced viscosity, the higher the molecular weight.
Specifically, a sample of polycarbonate resin (A) is dissolved in methylene chloride as a solvent to prepare a solution with a concentration of 0.6 g/dL. Measurement is performed at a temperature of 20.0±0.1° C. using an Ubbelohte viscometer (manufactured by Moritomo Rika Kogyo Co., Ltd.), and the relative viscosity _{η rel} is calculated from the passage time t of the solvent and the passage time t of the solution according to the following formula:
η _rel = t/t ₀
Well, the specific viscosity η _sp is calculated from the relative viscosity according to the following formula.
η _sp = (η - η ₀ ) / η ₀ = η _rel -1
Next, the specific viscosity is divided by the concentration c (g/dL) to obtain the reduced viscosity η _sp /c.

(Components other than polycarbonate)
The polycarbonate resin (A) preferably contains a catalyst deactivator. The catalyst deactivator is not particularly limited as long as it is an acidic substance that has a function of deactivating the polymerization catalyst, and examples thereof include phosphoric acid, trimethyl phosphate, triethyl phosphate, phosphorous acid, phosphonium salts such as octyl sulfonate tetrabutyl phosphonium salt, benzenesulfonate tetramethyl phosphonium salt, benzenesulfonate tetrabutyl phosphonium salt, dodecylbenzenesulfonate tetrabutyl phosphonium salt, and p-toluenesulfonate tetrabutyl phosphonium salt; ammonium salts such as decylsulfonate tetramethylammonium salt, and dodecylbenzenesulfonate tetrabutylammonium salt; and alkyl esters such as benzenesulfonate methyl, benzenesulfonate butyl, p-toluenesulfonate methyl, p-toluenesulfonate butyl, and hexadecylsulfonate ethyl.

The catalyst deactivator preferably contains a phosphorus-based compound (hereinafter also referred to as a "specific phosphorus-based compound") containing either a partial structure represented by formula (5) or a partial structure represented by formula (6). The specific phosphorus-based compound is added after the polycondensation reaction is completed, that is, during the kneading process or pelletizing process, for example, to deactivate the polymerization catalyst described below, and can suppress the unnecessary progress of the polycondensation reaction thereafter. As a result, the progress of polycondensation caused by heating the polycarbonate resin (A) when molding the resin composition of the present invention can be suppressed. In addition, by deactivating the polymerization catalyst, coloration of the polycarbonate resin (A) at high temperatures can be further suppressed.

Specific examples of the specific phosphorus-based compound containing the partial structure represented by formula (5) or the partial structure represented by formula (6) include phosphoric acid, phosphorous acid, phosphonic acid, hypophosphorous acid, polyphosphoric acid, phosphonic acid esters, and acidic phosphoric acid esters. Among the specific phosphorus-based compounds, from the viewpoint of the effect of catalyst deactivation and coloration inhibition, at least one selected from the group consisting of phosphorous acid, phosphonic acid, and phosphonic acid esters is preferred, and phosphorous acid is more preferred.
The specific phosphorus-based compounds may be used alone or in combination of two or more.

The content of the specific phosphorus compound contained in the polycarbonate resin (A) is not particularly limited, but is preferably 0.1 to 5 mass ppm in terms of phosphorus atoms. In this case, the effect of the specific phosphorus compound in preventing catalyst deactivation and coloring can be sufficiently obtained. In addition, in this case, coloring of the polycarbonate resin can be further prevented, particularly in durability tests at high temperatures and high humidity.

In addition, by adjusting the content of the specific phosphorus-based compound according to the amount of the polymerization catalyst, the effect of suppressing catalyst deactivation and coloration can be more reliably obtained. The content of the specific phosphorus-based compound is preferably 0.5 to 5 times the mol of phosphorus atoms per mol of metal atoms of the polymerization catalyst, more preferably 0.7 to 4 times the mol, and even more preferably 0.8 to 3 times the mol.

<Acrylic resin (B)>
The acrylic resin (B) may be a homopolymer of methyl methacrylate (MMA) (hereinafter also referred to as "polymer (B2)"), or a methyl methacrylate copolymer (hereinafter also referred to as "polymer (B1)") in which the content of repeating units derived from MMA (MMA units) is 95 mass% or more and less than 100 mass% based on the total mass of the acrylic resin (B).

(Other monomers)
The monomer other than MMA for constituting the polymer (B1) (hereinafter also referred to as "other monomer") is not particularly limited as long as it is copolymerizable with MMA, and examples thereof include (meth)acrylic acid ester monomers (excluding methyl methacrylate), aromatic vinyl compounds, unsaturated nitrile compounds, ethylenically unsaturated ether compounds, halogenated vinyl compounds, and aliphatic conjugated diene compounds.

Specific examples of the (meth)acrylic acid ester monomer (excluding methyl methacrylate) are methyl acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, n-nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, undecyl (meth)acrylate, n-amyl (meth)acrylate, isoamyl (meth)acrylate, lauryl (meth)acrylate, benzyl (meth)acrylate, phenyl (meth)acrylate, cyclohexyl (meth)acrylate, methoxyethyl (meth)acrylate, ethoxyethyl (meth)acrylate, 2-naphthyl (meth)acrylate, and phenoxymethyl (meth)acrylate.
The (meth)acrylic acid ester monomer (excluding methyl methacrylate) is preferably an alkyl acrylate having an alkyl group moiety with 1 to 8 carbon atoms, more preferably methyl acrylate.

Specific examples of the aromatic vinyl compound are styrene, α-methylstyrene, o-methylstyrene, p-methylstyrene, o-ethylstyrene, p-ethylstyrene, o-chlorostyrene, p-chlorostyrene, p-methoxystyrene, p-acetoxystyrene, α-vinylnaphthalene, and 2-vinylfluorene.

Specific examples of the unsaturated nitrile compound are acrylonitrile, α-chloroacrylonitrile, α-methoxyacrylonitrile, methacrylonitrile, and vinylidene cyanide.

Specific examples of the ethylenically unsaturated ether compound are methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, isopropyl vinyl ether, methyl allyl ether, and ethyl allyl ether.

Specific examples of the vinyl halide compounds are vinyl chloride, vinylidene chloride, 1,2-dichloroethylene, vinyl bromide, vinylidene bromide, and 1,2-dibromoethylene.

Specific examples of the aliphatic conjugated diene compounds are 1,3-butadiene, 2-methyl-1,3-butadiene, 2,3-dimethyl-1,3-butadiene, 2-neopentyl-1,3-butadiene, 2-chloro-1,3-butadiene, 1,2-dichloro-1,3-butadiene, 2,3-dichloro-1,3-butadiene, 2-bromo-1,3-butadiene, 2-cyano-1,3-butadiene, substituted linear conjugated pentadiene, and linear and side-chain conjugated hexadienes.

The other monomers may be used alone or in combination of two or more.
Among these other monomers, at least one selected from the group consisting of methyl acrylate, ethyl acrylate, and n-butyl acrylate is more preferable, and methyl acrylate or ethyl acrylate is even more preferable, since it is less likely to impair the inherent performance of the (meth)acrylic resin and tends to provide an excellent thermal decomposition resistance of a molded article.

(Weight average molecular weight)
The lower limit of the mass average molecular weight of the acrylic resin (B) is preferably 25,000 or more, more preferably 30,000 or more, and even more preferably 35,000 or more. The upper limit of the mass average molecular weight of the acrylic resin (B) is preferably 400,000 or less, more preferably 300,000 or less, and even more preferably 200,000 or less.
When the mass average molecular weight of the acrylic resin (B) is 25,000 or more, the resin composition has excellent mechanical properties, and when the mass average molecular weight of the acrylic resin (B) is 400,000 or less, the resin composition has excellent melt flowability.

The mass average molecular weight of the acrylic resin (B) was measured by gel permeation chromatography using standard polymethyl methacrylate as a standard sample.

(Method for producing acrylic resin (B))
The acrylic resin (B) can be obtained by polymerizing a monomer raw material containing MMA (hereinafter also referred to as "monomer raw material (1)") using a known polymerization method.
The lower limit of the content of MMA contained in the monomer raw material (1) is preferably 95% by mass or more, more preferably 96% by mass or more, and even more preferably 99% by mass or more, based on 100% by mass of the total mass of the monomer raw material (1), from the viewpoint of excellent scratch resistance and transparency of the resin composition of the present invention and the molded article of the resin composition of the present invention. On the other hand, the upper limit of the content of MMA units in the monomer raw material (1) is not particularly limited, and may be 100% by mass or less than 100% by mass, based on the total mass of the monomer raw material (1).

When the acrylic resin (B) is a polymer (B1), it is obtained by polymerizing a monomer raw material (hereinafter also referred to as "monomer raw material (2)") containing 95% by mass or more and less than 100% by mass of MMA and more than 0% by mass and 5% by mass or less of the other monomers by a known polymerization method.

The upper limit of the content of the other monomers contained in the monomer raw material (2) is preferably 5 mass% or less, and more preferably 1 mass% or less, based on the total mass of the monomer raw material (2), in order to prevent the inherent performance of the (meth)acrylic resin from being impaired.
The other monomers are more preferably methyl acrylate, ethyl acrylate, and n-butyl acrylate, and even more preferably methyl acrylate and ethyl acrylate, because they are less likely to impair the inherent performance of the (meth)acrylic resin and the molded article tends to have excellent thermal decomposition resistance.
Examples of the polymerization method of the monomer include bulk polymerization, suspension polymerization, emulsion polymerization, solution polymerization, etc. Among these polymerization methods, bulk polymerization, suspension polymerization, and emulsion polymerization are preferred because they facilitate the formation of a composite between the acrylic resin (B) and the acrylic-silica composite (X), which will be described later.

In order to adjust the mass average molecular weight of the acrylic resin (B), a chain transfer agent may be used when polymerizing the monomer raw material. Examples of the chain transfer agent include known mercaptan compounds, α-methylstyrene dimers, known terpinolene compounds, and the like. These chain transfer agents may be used alone or in combination of two or more types.

The amount of the chain transfer agent used is preferably 0.05 parts by mass or more and 2 parts by mass or less, and more preferably 0.07 parts by mass or more and 1.5 parts by mass or less, relative to 100 parts by mass of the monomer raw material. When the amount of the chain transfer agent used is 0.05 parts by mass or more, the resin composition has excellent melt flow properties. Furthermore, when the amount of the chain transfer agent used is 2 parts by mass or less, the resin composition and the obtained molded article have excellent mechanical strength.

<Mass Ratio of Polycarbonate Resin (A) to Acrylic Resin (B)>
The mass ratio of the polycarbonate resin (A) to the acrylic resin (B) contained in the resin composition of the present invention, i.e., "total mass of the polycarbonate resin (A):total mass of the acrylic resin (B)", is not particularly limited, but is preferably polycarbonate resin (A):acrylic resin (B) = 90:10 to 10:90, more preferably 80:20 to 20:80, and even more preferably 70:30 to 30:70. When the mass ratio of the polycarbonate resin (A) to the acrylic resin (B) is within the above range, a resin composition with excellent transparency can be obtained.

<Components other than polycarbonate resin (A) and acrylic resin (B)>
The resin composition of the present invention may contain components other than the polycarbonate resin (A) and the acrylic resin (B) as long as the effects of the present invention are not impaired.
Such components are not particularly limited as long as they are generally known as additives to resin compositions, and examples thereof include resin additives such as heat stabilizers, neutralizing agents, ultraviolet absorbers, release agents, colorants, antistatic agents, slip agents, lubricants, plasticizers, compatibilizers, and flame retardants.

[Method of producing resin composition]
The resin composition of the present invention can be produced by kneading the polycarbonate resin (A) and the acrylic resin (B).

The polycarbonate resin (A) and the acrylic resin (B) are mixed using a mixer equipped with a disk-shaped segment having a shaft-through portion through which the rotating shaft of the mixer passes freely and a number of small holes that serve as flow paths for the material to be mixed, drilled around the shaft-through portion.

The temperature during kneading of the polycarbonate resin (A) and the acrylic resin (B) is not particularly limited, but is preferably 200 to 240°C. By keeping the kneading temperature at 200°C or higher, it is possible to knead the resins and obtain a resin composition without exceeding the designed pressure resistance of the kneader. In addition, by keeping the kneading temperature at 240°C or lower, a large pressure loss is applied to the resin during kneading, making it possible to reduce the dispersion size of the resin in the resin composition.

The pressure loss during kneading of the polycarbonate resin (A) and the acrylic resin (B) is not particularly limited, but is preferably 1 to 20 MPa. By keeping the pressure loss during kneading at 20 MPa or less, it is possible to knead the resins and obtain a resin composition without exceeding the designed pressure resistance of the kneader. In addition, by keeping the pressure loss during kneading at 1 MPa or more, it is possible to reduce the dispersion size of the resin in the resin composition.

When polycarbonate resin (A) and acrylic resin (B) are kneaded to produce the resin composition of the present invention, the mass ratio of polycarbonate resin (A) to acrylic resin (B), i.e., "total mass of polycarbonate resin (A):total mass of acrylic resin (B)", is not particularly limited, but is preferably polycarbonate resin (A):acrylic resin (B) = 90:10 to 10:90, more preferably 80:20 to 20:80, and even more preferably 70:30 to 30:70. When the mass ratio of polycarbonate resin (A) to acrylic resin (B) is within the above range, a resin composition with superior transparency is obtained.

<Kneading machine>
The kneading machine used for kneading the polycarbonate resin (A) and the acrylic resin (B) will be described.
As shown in FIG. 1, the kneader for kneading the resin composition of this embodiment includes a disk-shaped segment having a shaft-penetrating portion through which the rotating shaft of the kneader passes freely to rotate, and a plurality of small holes that serve as flow paths for the material to be kneaded and are drilled around the shaft-penetrating portion.
As shown in FIG. 1, the disk-shaped segment 22 includes a disk body 221 and a shaft penetrating portion 222 through which the rotating shaft of the kneader passes so as to be rotatable.
Examples of the shaft through portion 222 include bearings such as ball bearings, sleeve bearings, and roller bearings.
The disk-shaped segment 22 does not rotate with the rotation of the rotating shaft of the kneader, and remains fixed during kneading and extrusion.
A plurality of small holes 221a are formed around the shaft through portion 222 to serve as flow paths for the material to be kneaded.
The disk-type segment 22 of this embodiment is a fixed type that does not rotate with the rotation of the rotary shaft of the kneader, and the kneading material passes through the small holes 221a very efficiently. The inventors have found that by applying a large pressure drop and passing through the small holes, the dispersion of each resin in the resin composition is improved by elongational flow.

In the kneader of this embodiment, it is preferable to ensure a pressure loss necessary for the desired dispersion within the designed pressure limit of the kneader, while being careful not to exceed the designed pressure limit of the kneader.
Therefore, it is desirable to design the diameter, axial thickness, number, total opening area of the small holes 221a on the resin flow inlet side, position, extrusion speed, etc. of the small holes 221a taking into consideration the design pressure resistance and dispersibility of the kneader. For example, the pressure loss can be increased by making the small holes thicker, but since the inside of the small holes is a pure shear action, it is desirable to make them as thin as possible to avoid shear heat generation. In addition, the more the number of small holes, the better the distribution action of the nanoparticles can be expected. The diameter of the small holes is usually determined taking into consideration the size of the nanoparticles of the resin additive. From this point of view, a preferable range is described below as an example. That is, for example, the diameter of the small holes 221a can be 0.5 to 1.5 mm, the thickness of the small holes 221a in the axial direction can be 1/12 to 1/4 in terms of the ratio (L/D) of the thickness (L) to the inner diameter (D) of the shaft through part 222, and the number of the small holes 221a can be 2 to 64. In addition, the total opening area of the small holes 221a on the resin flow inlet side can be, for example, 4 to 20% of the inner cross-sectional area of the kneader barrel, preferably within 20%, and more preferably within 10%.

In the kneader of this embodiment, as shown in FIG. 1, 30 small holes 221a are arranged in a row in a concentric circle on the shaft through-hole 222. Alternatively, two or more rows of small holes may be arranged. Also, although no small holes are drilled between two shaft through-holes 222, this is not limited thereto, and small holes may be drilled between multiple shaft through-holes 222.

The present invention will be described in more detail below with reference to experimental examples, but the scope of the present invention is not limited to the following experimental examples.
In the following experimental examples, "parts" refers to "parts by mass."
Experimental Examples 1 to 4 are working examples, and Experimental Example 5 is a comparative example.

[Evaluation method]
The evaluations in the experimental examples were carried out by the following methods.

(Haze rating)
As an index of transparency of the 2 mm-thick plate-like molded bodies obtained in Experimental Examples 1 to 5, the plate-like molded bodies were used as test pieces in accordance with JIS K 7316:2013 using a haze meter (manufactured by Nippon Denshoku Industries Co., Ltd., device name: NDH2020). The haze (unit: %) was measured at room temperature of 23 ° C.
The haze value at room temperature of 23° C. was evaluated in three stages according to the following criteria.
A: Haze is 0.0 or more and less than 20%. B: Haze is 20% or more and less than 50%. C: Haze is 50% or more.

[Production Example of Polycarbonate Resin]
[Ingredients used]
The abbreviations and manufacturers of the compounds used in the following Production Examples are as follows.
<Dihydroxy Compound>
ISB: Isosorbide [manufactured by Rocket Fleuret]
CHDM: 1,4-cyclohexanedimethanol (SK Chemical)
<Carbonate diester>
DPC: diphenyl carbonate (manufactured by Mitsubishi Chemical Corporation)
<Catalyst Deactivator>
Phosphorous acid (manufactured by Taihei Chemical Industry Co., Ltd.; molecular weight 82.0)
<Heat stabilizer (antioxidant)>
Irganox 1010: Pentaerythritol-tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (manufactured by BASF)
AS2112: Tris(2,4-di-tert-butylphenyl)phosphite (manufactured by ADEKA Corporation; molecular weight 646.9)
<Release Agent>
E-275: Ethylene glycol distearate (manufactured by NOF Corporation)

[Production Example 1: Polycarbonate resin (A-1)]
A continuous polymerization facility consisting of three vertical stirring reactors, one horizontal stirring reactor, and a twin-screw extruder was used to polymerize polycarbonate resin. Specifically, ISB, CHDM, and DPC were melted in tanks, respectively, and continuously fed to the first vertical stirring reactor at flow rates of 35.2 kg/hr for ISB, 14.9 kg/hr for CHDM, and 74.5 kg/hr for DPC (molar ratio ISB/CHDM/DPC=0.700/0.300/1.010). At the same time, an aqueous solution of calcium acetate monohydrate was fed to the first vertical stirring reactor so that the amount of calcium acetate monohydrate added as a catalyst was 1.5 μmol per 1 mol of the total dihydroxy compound. The reaction temperature, internal pressure, and residence time of each reactor were as follows: first vertical stirring reactor: 190°C, 25 kPa, 90 minutes, second vertical stirring reactor: 195°C, 10 kPa, 45 minutes, third vertical stirring reactor: 210°C, 3 kPa, 45 minutes, fourth horizontal stirring reactor: 225°C, 0.5 kPa, 90 minutes. The internal pressure of the fourth horizontal stirring reactor was finely adjusted during operation so that the reduced viscosity of the resulting polycarbonate resin was 0.41 dL/g to 0.43 dL/g.

A polycarbonate resin was extracted from the fourth horizontal stirring reactor at a rate of 60 kg/hr, and the resin was then supplied in a molten state to a vented twin-screw extruder [TEX30α, manufactured by Japan Steel Works, Ltd., L/D: 42.0, L (mm): screw length, D (mm): screw diameter].
The polycarbonate resin that had passed through the extruder was passed through a candle-type filter (made of SUS316) with a mesh size of 10 μm while still in a molten state to filter out foreign matter. The polycarbonate resin was then discharged in the form of strands from the die, cooled with water, solidified, and pelletized with a rotary cutter to obtain a polycarbonate resin with a molar ratio of ISB/CHDM of 70/30 mol%. In Table 1, the obtained polycarbonate resin is indicated as "(A-1)".

The extruder had three vacuum vents, where residual low molecular weight components in the resin were degassed and removed. Just before the second vent, 2000 ppm of water was added to the resin, and water injection degassing was performed. Just before the third vent, 0.1 parts by mass, 0.05 parts by mass, and 0.3 parts by mass of Irganox 1010, AS2112, and E-275 were added to 100 parts by mass of polycarbonate resin, respectively. In this way, ISB/CHDM copolymer polycarbonate resin pellets were obtained. 0.65 ppm by mass of phosphorous acid (0.24 ppm by mass as phosphorus atoms) was added to the polycarbonate resin as a catalyst deactivator. The phosphorous acid was added as follows. A master batch was prepared by mixing the polycarbonate resin pellets obtained in Production Example 1 with an ethanol solution of phosphorous acid, and feeding the master batch to the extruder just before the first vent port (the resin feed port side of the extruder) so that the master batch was 1 part by mass per 100 parts by mass of polycarbonate resin in the extruder.

[acrylic resin]
Acrypet VH001 (manufactured by Mitsubishi Chemical Corporation, hereinafter referred to as B-1) was used as the acrylic resin (B).

[Experimental Example 1]
70 parts of pellets of polycarbonate resin (A-1) and 30 parts of pellets of acrylic resin (B-1) obtained in Production Example 1 were placed at the outlet of a hydraulic cylinder with a disk-shaped segment 22 shown in the figure, melted in an Atsukan servo unit (manufactured by TAIYO) heated to 220°C, and discharged into a plate-shaped mold having a thickness of 2 mm under the condition of a pressure loss of 4.0 MPa. The haze of the resin composition test piece kneaded by the obtained elongational flow was measured.
The results are shown in Table 1. The haze was evaluated as A.

[Experimental Examples 2 to 4]
Resin composition test pieces were obtained in the same manner as in Experimental Example 1 except that the conditions were changed to those shown in Table 1, and the haze was measured.
The results are shown in Table 1. The haze evaluation was B for Experimental Examples 2 and 4, and A for Experimental Example 3.

[Experimental Example 5]
70 parts of the polycarbonate resin (A-1) pellets obtained in Production Example 1 and 30 parts of the acrylic resin (B-1) pellets were melt-kneaded using a 35 mm twin-screw extruder (TEM-35B manufactured by Toshiba Machine Co., Ltd.) equipped with a kneading disk in the shaft at a cylinder temperature of 220° C. to obtain a pellet-shaped resin composition. The obtained pellet-shaped resin composition was molded using a 100 ton injection molding machine (IS-100 manufactured by Toshiba Machine Co., Ltd.) to obtain a resin composition test piece having a thickness of 2 mm, and the haze was measured.
The results are shown in Table 1. The haze was evaluated as C.

Looking at the results of Experimental Example 5, which is a comparative example, it can be seen that the dispersed size of the resin becomes large in the molded plate obtained by kneading with a twin-screw extruder equipped with a kneading disk, and that the transparency of the test piece is inferior to that of Experimental Examples 1 to 4, which are examples in which the resin is dispersed by extensional flow, in terms of haze.

22 Disk-shaped segment 221 Disk body 221a Small hole 222 Shaft through-hole

Claims (5)

A resin composition obtained by kneading a polycarbonate resin having a structural unit derived from a compound represented by formula (1) with an acrylic resin,
A resin composition obtained by kneading the polycarbonate resin and the acrylic resin using a kneader equipped with a disk-shaped segment having a plurality of shaft-penetrating portions through which the rotating shaft of the kneader passes freely to allow free rotation, and a plurality of small holes that serve as flow paths for the kneading material and are drilled around the plurality of shaft-penetrating portions.

The resin composition according to claim 1, wherein the mass ratio of the polycarbonate resin to the acrylic resin is 90:10 to 10:90. A method for producing a resin composition by kneading a polycarbonate resin having a structural unit derived from a compound represented by formula (1) with an acrylic resin,
The polycarbonate resin and the acrylic resin are kneaded using a kneader equipped with a disk-shaped segment having a plurality of shaft-penetrating portions through which a rotating shaft of the kneader passes to allow free rotation, and a plurality of small holes that serve as flow paths for the material to be kneaded and are drilled around the plurality of shaft-penetrating portions.

The method for producing the resin composition according to claim 3, wherein the kneading is carried out at a temperature of 200 to 240°C. The method for producing a resin composition according to claim 3 or 4, wherein the pressure loss during kneading is 1 to 20 MPa.

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