JP7633016B2 - Organic-inorganic composite composition - Google Patents

Description

The present invention relates to an organic-inorganic composite composition containing a polycarbonate resin and inorganic fine particles.

In recent years, there has been active development of optical materials. For example, in the field of optical lens materials, there is a demand for optical materials with high refractive index, high Abbe number, heat resistance, and excellent transparency. The glass that has been used traditionally is capable of achieving the various required optical properties and has excellent environmental resistance, but it has the problem of poor processability. In response to this, resin materials, which are cheaper and more processable than glass materials, have come to be used for optical components. However, since resins generally have a lower refractive index than glass, it is necessary to increase the refractive index of the material itself in order to make optical components thinner.

One method for increasing the refractive index is to uniformly disperse fine particles of inorganic oxides, such as titanium oxide and zirconium oxide, in the resin. However, because such fine particles have a large surface energy, it is difficult to disperse them uniformly in the matrix resin, and various studies have been conducted to date.

One method for dispersing fine particles uniformly in a resin is to chemically modify the surface of the fine particles with a surface modifier. For example, Patent Document 1 describes a method in which fine particles modified with a specific chemical structure are mixed with a resin to prepare a master batch, which is then melt-kneaded with a thermoplastic resin to obtain a transparent resin composition. Although this method improves dispersibility to a certain extent by selecting a surface modifier, it is still difficult to say that sufficient dispersibility is obtained. In addition, there is a problem that the content of inorganic fine particles is low and is not sufficient in terms of increasing the refractive index.

Patent Document 2 describes a method of introducing carboxyl groups to the terminals of a polycarbonate resin after polymerization, and a method of obtaining a carboxyl-containing polycarbonate resin by copolymerizing a diol compound having a carboxyl group, and describes that a film composited with inorganic fine particles has excellent transparency. The method of introducing carboxyl groups to the terminals utilizes the reaction between hydroxyl groups at the polymer terminals and acid anhydrides. In this method, a multifunctional compound is used as the acid anhydride, so gelation may be a problem, especially in processing at high temperatures. In addition, in the copolymerization method, the carboxyl groups react with other diol compounds during polymerization, making it difficult to control the amount of carboxyl groups introduced, and the dispersion stability of the inorganic fine particles may be a problem, especially under high temperature conditions.

JP 2011-38012 A JP 2018-138624 A

In order to increase the refractive index of polycarbonate, a method of designing the molecular structure of the polymer to improve the electron density is commonly used, but the method of increasing the refractive index by uniformly dispersing fine particles in the resin is hardly used in practice. This is because, in addition to the difficulty of obtaining a resin composition in which fine particles are uniformly dispersed, as described above, even if such a resin composition is obtained, when the resin composition is molded, the dispersion state of the fine particles may change and the fine particles may aggregate.

The object of the present invention is to provide an organic-inorganic composite composition in which inorganic fine particles are sufficiently dispersed in a polycarbonate resin, so that the composition can be practically used as an optical resin even after molding.

As a result of extensive research, the inventors have found that the dispersibility of inorganic particles in polycarbonate resin can be improved by using a polycarbonate resin having a specific structural unit at the polymer chain end, and have demonstrated that an organic-inorganic composite composition containing the polycarbonate resin and inorganic particles has excellent transparency, moldability, and refractive index, thereby completing the present invention.

That is, according to the present invention, the object of the invention is achieved as follows.
1. An organic-inorganic hybrid composition comprising a polycarbonate resin containing a structural unit represented by the following formula (1) at a polymer chain end, and inorganic fine particles:

In formula (1), R ¹ and R ² may be independent or the same and represent at least one group selected from the group consisting of a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, a cycloalkyl group, a cycloalkoxy group, an alkenyl group, an aryl group, an aryloxy group, an aralkyl group, an aralkyloxy group, a nitro group, an aldehyde group, and a cyano group; a and b each represent an integer of 1 to 2; X represents a single bond or a group represented by the following formula (2):

wherein ^R5 represents at least one group selected from the group consisting of an alkylene group, an aralkylene group, an arylene group, and a cycloalkylene group; ^R3 and ^R4 each independently represent at least one group selected from the group consisting of an alkylene group, an aralkylene group, an arylene group, and a cycloalkylene group; and a hydrogen atom in ^R4 may be substituted with a carboxyl group.

2. The organic-inorganic hybrid composition according to the above item 1, wherein the molar ratio of the polymer chain end is from 1.0 mol % to 10 mol % based on 100 mol % of all carbonate repeating units.
3. The organic-inorganic hybrid composition according to item 1 or 2 above, wherein the formula (1) contains a structural unit represented by the following formula (3):

(In formula (3), ^R6 represents at least one group selected from the group consisting of a single bond, an alkylene group, an aralkylene group, an arylene group, and a cycloalkylene group.)

4. The organic-inorganic hybrid composition according to the preceding paragraph 1 or 2, wherein the formula (1) contains a structural unit represented by the following formula (4):

(In formula (4), ^R7 represents at least one group selected from the group consisting of an alkylene group, an aralkylene group, an arylene group, and a cycloalkylene group.)

5. The organic-inorganic hybrid composition according to any one of items 1 to 4 above, wherein the polycarbonate resin has a carboxyl group amount of 1 eq/ton to 200 eq/ton.
6. The organic-inorganic hybrid composition according to any one of items 1 to 5 above, wherein the surfaces of the inorganic fine particles are modified with a surface modifying agent.
7. The organic-inorganic hybrid composition according to item 6 above, wherein the surface modifier has an acidic functional group.
8. The organic-inorganic hybrid composition according to item 7 above, wherein the acidic functional group is at least one acidic functional group selected from the group consisting of a sulfonic acid group, a phosphonic acid group, a phosphinic acid group, and a carboxylic acid group.
9. The organic-inorganic hybrid composition according to any one of items 6 to 8 above, wherein the surfaces of the inorganic fine particles are modified with the surface modifying agent in an amount of 1 to 30% by mass based on the inorganic fine particles.
10. The organic-inorganic hybrid composition according to any one of items 1 to 9 above, wherein the inorganic fine particles have an average particle size of 1 to 20 nm.
11. The organic-inorganic hybrid composition according to any one of items 1 to 10 above, wherein the content of the inorganic fine particles is 1 to 50% by mass based on the polycarbonate resin.
12. The organic-inorganic hybrid composition according to any one of items 1 to 11 above, wherein the inorganic fine particles are at least one selected from the group consisting of ZrO ₂ (zirconium oxide), TiO ₂ (titanium oxide), SnO ₂ (tin oxide), SiO ₂ (silicon oxide), and Al ₂ O ₃ (aluminum oxide).
13. A molded article obtained by using the organic/inorganic hybrid composition according to any one of items 1 to 12 above.
14. A film or sheet obtained by using the organic/inorganic hybrid composition according to any one of items 1 to 12 above.

According to the present invention, by using a polycarbonate resin having a specific structural unit at the polymer chain end and inorganic fine particles, it is possible to provide an organic-inorganic composite composition that has improved dispersibility of the inorganic fine particles in the polycarbonate resin and is excellent in transparency, moldability, and refractive index.

The photograph in FIG. 1 shows a TEM image of the organic-inorganic hybrid composition prepared in Example 1. The photograph in FIG. 2 shows a TEM image of the organic-inorganic hybrid composition prepared in Comparative Example 3.

The following describes in detail the embodiments of the present disclosure. The present disclosure is not limited to the following embodiments, and can be modified in various ways within the scope of the invention.

One aspect of the present invention is characterized by using a polycarbonate resin containing a structural unit having a carboxyl group at the polymer chain end, as represented by the above formula (1). The organic-inorganic composite composition of the present invention has excellent dispersion stability of inorganic fine particles under high temperature conditions, and is excellent in transparency, moldability, and refractive index.

On the other hand, the method described in the above Patent Document 2 uses a polymer having a carboxyl group at the side chain or end to produce an organic-inorganic composite composition with excellent transparency. However, according to the investigations of the present inventors, it has become clear that under high temperature conditions such as injection molding, the transparency decreases and decomposition occurs during molding, making it impossible to obtain a molded product.

Although it is not intended to limit the technical scope of the present invention, the mechanism by which such effects are obtained in the present invention is presumed to be as follows. By introducing a structural unit having a carboxyl group, such as that represented by the above formula (1), into the polymer chain end of a polycarbonate resin, it becomes easier to effectively coat the surface of inorganic fine particles, and a high level of transparency can be maintained even under high temperature conditions. Furthermore, since it becomes easier to coat the surface of inorganic fine particles, active hydroxyl groups on the surface of the inorganic fine particles are effectively shielded, so that hydrolysis of the polymer under high temperature conditions can be suppressed. As a result, it is possible to provide an organic-inorganic composite composition that can be molded under high temperature conditions while obtaining high transparency and simultaneously suppressing hydrolysis.

The present invention is described in detail below.

<Polycarbonate resin>
The polycarbonate resin used in the present invention is a polycarbonate resin having a structural unit represented by the following formula (1) at the polymer chain terminal.

In formula (1), R ¹ and R ² may be independent or the same, and each represents at least one group selected from the group consisting of a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, a cycloalkyl group, a cycloalkoxy group, an alkenyl group, an aryl group, an aryloxy group, an aralkyl group, an aralkyloxy group, a nitro group, an aldehyde group, and a cyano group, a and b each represent an integer of 1 to 2, and X represents a single bond or a group represented by the following formula (2):

wherein ^R5 represents at least one group selected from the group consisting of an alkylene group, an aralkylene group, an arylene group, and a cycloalkylene group; ^R3 and ^R4 each independently represent at least one group selected from the group consisting of an alkylene group, an aralkylene group, an arylene group, and a cycloalkylene group; and a hydrogen atom in ^R4 may be substituted with a carboxyl group.

In the above formula (1), preferably, R ¹ and R ² are each independently at least one group selected from the group consisting of a hydrogen atom, a halogen atom, an alkyl group having 1 to 18 carbon atoms, an alkoxy group having 1 to 18 carbon atoms, a cycloalkyl group having 6 to 20 carbon atoms, a cycloalkoxy group having 6 to 20 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an aryl group having 6 to 14 carbon atoms, an aryloxy group having 6 to 14 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, an aralkyloxy group having 7 to 20 carbon atoms, a nitro group, an aldehyde group, a cyano group, and a carboxyl group. When there are a plurality of ^{R 1} and R ² , they may be the same or different.

Halogen atoms include fluorine atoms, chlorine atoms, bromine atoms, etc.

Examples of alkyl groups having 1 to 18 carbon atoms include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, dodecyl, and tetradecyl groups. Preferred are alkyl groups having 1 to 6 carbon atoms.

Examples of alkoxy groups having 1 to 18 carbon atoms include methoxy, ethoxy, propoxy, butoxy, pentoxy, hexoxy, and octoxy groups. Alkoxy groups having 1 to 6 carbon atoms are preferred.

Examples of cycloalkyl groups having 6 to 20 carbon atoms include cyclohexyl and cyclooctyl groups. Cycloalkyl groups having 6 to 12 carbon atoms are preferred.

Preferred examples of cycloalkoxy groups having 6 to 20 carbon atoms include cyclohexyloxy groups and cyclooctyloxy groups. Cycloalkoxy groups having 6 to 12 carbon atoms are preferred.

Examples of alkenyl groups having 2 to 10 carbon atoms include methenyl, ethenyl, propenyl, butenyl, and pentenyl groups. Alkenyl groups having 2 to 6 carbon atoms are preferred.

Examples of aryl groups having 6 to 14 carbon atoms include phenyl groups and naphthyl groups. Examples of aryloxy groups having 6 to 14 carbon atoms include phenyloxy groups and naphthyloxy groups.

Examples of aralkyl groups having 7 to 20 carbon atoms include benzyl groups and phenylethyl groups. Examples of aralkyloxy groups having 7 to 20 carbon atoms include benzyloxy groups and phenylethyloxy groups.

Preferably, a and b in formula (1) are each an integer of 1 to 2, and more preferably, a and b are each an integer of 1.

Preferably, R ⁵ in formula (2) is at least one group selected from the group consisting of a single bond, an alkylene group having 1 to 10 carbon atoms, an aralkylene group having 7 to 20 carbon atoms, an arylene group having 6 to 10 carbon atoms, and a cycloalkylene group.

Preferably, R ³ and R ⁴ in formula (2) may be independent or the same and represent at least one group selected from the group consisting of an alkylene group, an alkylidene group, an aralkylene group, an arylene group, and a cycloalkylene group. Preferably, R ³ and R ⁴ may be independent or the same and represent an alkylene group having 1 to 10 carbon atoms, an arylene group having 6 to 10 carbon atoms, or an aralkylene group having 7 to 20 carbon atoms, more preferably an alkylene group having 1 to 6 carbon atoms, an arylene group having 6 to 10 carbon atoms, or an aralkylene group having 7 to 12 carbon atoms.

The molar ratio of the polymer chain end having the structural unit represented by the formula (1) is preferably 1.0 mol% or more and 10 mol% or less, more preferably 1.5 mol% or more and 8.0 mol% or less, even more preferably 2.0 mol% or more and 7.0 mol% or less, and particularly preferably 3.0 mol% or more and 6.0 mol% or less, relative to 100 mol% of all carbonate repeating units in the polycarbonate resin. If it is within the above range, the effects of the present invention can be fully exerted.

(Preferred embodiment (1))
In the present invention, a preferred embodiment (1) is one in which the formula (1) contains a structural unit represented by the following formula (3):

In formula (3), ^R6 represents at least one group selected from the group consisting of a single bond, an alkylene group, an aralkylene group, an arylene group, and a cycloalkylene group. ^R6 is preferably at least one group selected from the group consisting of a single bond, an alkylene group having 1 to 10 carbon atoms, an aralkylene group having 7 to 20 carbon atoms, an arylene group having 6 to 10 carbon atoms, and a cycloalkylene group.

The polycarbonate resin containing the structure represented by the above formula (3) at the polymer chain end is produced by using a method of using a phenolic compound having a carboxyl group as a terminal terminator in a reaction means known per se for producing a normal polycarbonate resin, or a method of performing a polymerization reaction using a phenolic compound having a carboxylic acid ester group as a terminal terminator and then performing an acid modification reaction to modify the carboxylic acid ester group to a carboxyl group, or by using both of these methods. Examples of the polymerization reaction method include an interfacial polycondensation method, a melt transesterification method, and a solid-phase transesterification method of carbonate prepolymer. Among them, from the viewpoint of quantitatively introducing the structure represented by formula (3) at the polymer chain end, a method in which a phenolic compound having a carboxyl group or a phenolic compound having a carboxylic acid ester group, or both of them, act as a terminal terminator in the interfacial polycondensation method is preferred.

Examples of phenol compounds having a carboxyl group that are used as end terminators include 4-hydroxybenzoic acid, 3-hydroxybenzoic acid, and 2-hydroxybenzoic acid. From the viewpoint of efficiency of introduction to the polymerization end, 4-hydroxybenzoic acid and 3-hydroxybenzoic acid are preferred, and 4-hydroxybenzoic acid is more preferred. These may be used alone or in combination of two or more types.

Examples of phenol compounds having a carboxylate group that are used as end terminators include tertiary butyl 4-hydroxybenzoate, isopropyl 4-hydroxybenzoate, and methyl 4-hydroxybenzoate. From the viewpoint of the efficiency of the deprotection reaction described below, tertiary butyl 4-hydroxybenzoate and isopropyl 4-hydroxybenzoate are preferred, and tertiary butyl 4-hydroxybenzoate is more preferred. These may be used alone or in combination of two or more. By making the carboxyl group into a carboxylate structure, hydrophobicity is improved, and it is easy to quantitatively introduce it into the polymer chain end.

Phenol compounds that do not have a carboxyl group or a carboxylic acid ester group may be used in combination as a terminal terminator. Examples of phenol compounds that do not have a carboxyl group or a carboxylic acid ester group include phenol, m-methylphenol, p-methylphenol, m-propylphenol, p-propylphenol, 1-phenylphenol, 2-phenylphenol, p-tert-butylphenol, p-cumylphenol, isooctylphenol, and p-long-chain alkylphenol. By using these phenol compounds that do not have a carboxyl group in combination as a terminal terminator, the amount of carboxyl groups at the polymer chain ends can be quantitatively adjusted, and the thermal stability of the organic-inorganic composite composition, the dispersibility of inorganic fine particles, and the fluidity when melted can be controlled.

In the method using a phenolic compound having a carboxylate group, a polycarbonate resin is produced by a polymerization reaction, and then the carboxylate group is converted to a carboxyl group by an acid modification reaction, so that the polymer chain end can have a structure represented by formula (3). The acid modification reaction can be, for example, but is not limited to, a method in which an acidic compound is applied, a method of heat treatment, or other known methods. From the viewpoint of reaction efficiency, the method using an acidic compound is preferred. Examples of acidic compounds include, but are not limited to, strong acidic compounds such as trifluoroacetic acid and hydrochloric acid. From the viewpoint of reaction efficiency, trifluoroacetic acid is particularly preferred.

The manufacturing process of the acid modification reaction using an acidic compound may be, for example, a process of dissolving the solidified polymer in a solvent and reacting with an acidic compound, or, in the case of a polymerization method using a solvent such as the interfacial polycondensation method, a process of reacting an acidic compound with the polymer solution after the polymerization reaction has been completed may be used.

(Preferred embodiment (2))
In a preferred embodiment (2) of the present invention, the formula (1) preferably contains a structural unit represented by the following formula (4):

In formula (4), ^R7 represents at least one group selected from the group consisting of an alkylene group, an aralkylene group, an arylene group, and a cycloalkylene group. ^R7 is preferably an alkylene group having 1 to 10 carbon atoms, an arylene group having 6 to 10 carbon atoms, or an aralkylene group having 7 to 20 carbon atoms, and more preferably an alkylene group having 1 to 6 carbon atoms, an arylene group having 6 to 10 carbon atoms, or an aralkylene group having 7 to 12 carbon atoms.

The polycarbonate resin having the structure represented by formula (4) used in the present invention can be produced, for example, by a step of producing a polycarbonate resin having a carbon-carbon double bond (step (I)) and a step of reacting the polycarbonate resin with a thiol compound having a carboxyl group (step (II)).

(Step I)
A polycarbonate resin having a carbon-carbon double bond at a polymer chain end is produced by using at least one phenol compound having a carbon-carbon double bond by a reaction means known per se for producing a normal polycarbonate resin. Examples of the reaction method include an interfacial polycondensation method, a melt transesterification method, and a solid-phase transesterification method of a carbonate prepolymer. Among them, from the viewpoint of quantitatively introducing the structure represented by formula (4) into the polymer chain end, a method in which a phenol compound having a carbon-carbon double bond acts as a terminal terminator in the interfacial polycondensation method is preferred.

Examples of phenol compounds having a carbon-carbon double bond that can be used as end terminators include parahydroxyallylphenol, metahydroxyallylphenol, and orthohydroxyallylphenol. From the viewpoint of efficiency of introduction to the polymerization end, orthohydroxyallylphenol is particularly preferred. These may be used alone or in combination of two or more types.

Phenol compounds that do not have a carbon-carbon double bond may be used in combination as a terminal terminator. Examples of phenol compounds that do not have a carbon-carbon double bond include phenol, m-methylphenol, p-methylphenol, m-propylphenol, p-propylphenol, 1-phenylphenol, 2-phenylphenol, p-tert-butylphenol, p-cumylphenol, isooctylphenol, and p-long-chain alkylphenol. By using these phenol compounds that do not have a carbon-carbon double bond in combination as a terminal terminator, the amount of carboxyl groups at the polymer chain end can be quantitatively adjusted, and the thermal stability of the organic-inorganic composite composition, the dispersibility of inorganic fine particles, and the flowability when melted can be controlled.

(Step II)
The polycarbonate resin having the carbon-carbon double bond produced in step (I) is reacted with a thiol compound having a carboxyl group (enethiol reaction) to produce a polycarbonate resin having a structure represented by the formula (4). The enethiol reaction is a reaction in which a carbon-carbon double bond and a thiol group are added in a one-to-one ratio. That is, when a thiol is irradiated with light or a radical generator is added, a thiyl radical is easily generated and added to the carbon-carbon double bond. The carbon radical thus generated extracts hydrogen from the thiol group to produce a one-to-one adduct. The thiol group from which hydrogen has been extracted becomes a thiyl radical, and the reaction proceeds in a chain reaction. In this way, the enethiol reaction can be used to quantitatively produce a polycarbonate resin having a carboxyl group in a high yield.

Examples of thiol compounds having a carboxyl group include 3-mercaptopropanoic acid, 3-mercapto-2-methylpropanoic acid, mercaptosuccinic acid, 2-mercaptobenzoic acid, and 1-(mercaptomethyl)cyclopropaneacetic acid.

In the enethiol reaction, it is preferable to use a radical generator as a reaction catalyst. However, it may also be a radical reaction caused by irradiation with light (ultraviolet rays). Examples of radical generators include azo compounds and organic peroxides, and either one that generates radicals by heat or by irradiation with light can be suitably used. Examples of azo compounds include azobisisobutyronitrile (AIBN) and 1,1'-azobis(cyclohexanecarbonitrile) (ABCN). Examples of organic peroxides include di-tert-butyl peroxide and benzoyl peroxide.

More specifically, the enethiol reaction can be carried out by dissolving a polycarbonate resin having a carbon-carbon double bond, a thiol compound having a carboxyl group, and a radical generator in an organic solvent and maintaining the solution under conditions in which radicals are generated. Examples of organic solvents include alcohols (alkyl alcohols such as ethanol, propanol, and isopropanol, glycols such as ethylene glycol and propylene glycol, etc.), hydrocarbons (aliphatic hydrocarbons such as hexane, alicyclic hydrocarbons such as cyclohexane, aromatic hydrocarbons such as toluene and xylene, etc.), halogenated hydrocarbons (methylene chloride, chloroform, etc.), ethers (chain ethers such as dimethyl ether and diethyl ether, cyclic ethers such as dioxane and tetrahydrofuran, etc.), esters (methyl acetate, ethyl acetate, butyl acetate, ethyl lactate, ethyl butyrate, etc.), ketones (acetone, ethyl methyl ketone, methyl isobutyl ketone, cyclohexanone, N-methyl-2-pyrrolidone, etc.), Examples of organic solvents include cellosolves (methyl cellosolve, ethyl cellosolve, butyl cellosolve, etc.), carbitols (methyl carbitol, ethyl carbitol, butyl carbitol, etc.), propylene glycol monoalkyl ethers (propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol mono n-butyl ether, etc.), glycol ether esters (ethylene glycol monomethyl ether acetate, propylene glycol monomethyl ether acetate, etc.), amides (N,N-dimethylformamide, N,N-dimethylacetamide, etc.), sulfoxides (dimethyl sulfoxide, etc.), nitriles (acetonitrile, benzonitrile, etc.), and N-methylpyrrolidone. The organic solvents may be used alone or in combination of two or more kinds. The reaction temperature is not particularly limited, but is preferably 50 to 120°C.

(Other units)
As the unit other than the polymer chain end, i.e., the unit of the main chain, various diol compounds can be mentioned. Such diol compounds may be any of aromatic diol compounds, aliphatic diol compounds, and alicyclic diol compounds, and include the diol compounds described in WO 2004/111106 and WO 2011/021720, and oxyalkylene glycols such as diethylene glycol, triethylene glycol, tetraethylene glycol, and polyethylene glycol. These may be used alone or in combination of two or more. Representative specific examples of the diol component are shown below, but the other components of the present invention are not limited thereto.

Specific examples of aromatic diol compounds include 4,4'-biphenol, 3,3',5,5'-tetrafluoro-4,4'-biphenol, α,α'-bis(4-hydroxyphenyl)-o-diisopropylbenzene, α,α'-bis(4-hydroxyphenyl)-m-diisopropylbenzene (usually referred to as "BPM"), α,α'-bis(4-hydroxyphenyl)-p-diisopropylbenzene, α,α'-bis(4-hydroxyphenyl)-m-bis(1,1,1,3,3,3-hexafluoroisopropyl)benzene, 1,1-bis(4-hydroxyphenyl) 1,1-bis(4-hydroxyphenyl)cyclohexane, 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane, 1,1-bis(4-hydroxyphenyl)-4-isopropylcyclohexane, 1,1-bis(3-cyclohexyl-4-hydroxyphenyl)cyclohexane, 1,1-bis(4-hydroxyphenyl)cyclopentane, 1,1-bis(3-fluoro-4-hydroxyphenyl)cyclohexane, 1,1-bis(4-hydroxyphenyl)perfluorocyclohexane, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxy-3,3'-di Methyl diphenyl ether, 4,4'-dihydroxydiphenyl sulfone, 4,4'-dihydroxydiphenyl sulfoxide, 4,4'-dihydroxydiphenyl sulfide (hereinafter sometimes abbreviated as "TDP"), 3,3'-dimethyl-4,4'-dihydroxydiphenyl sulfide (hereinafter sometimes abbreviated as "HMPS"), 3,3'-dimethyl-4,4'-dihydroxydiphenyl sulfone, 4,4'-dihydroxydiphenyl sulfone, 4,4'-dihydroxy-3,3'-diphenyl sulfide, 4,4'-dihydroxy-3,3'-diphenyl sulfoxide , 4,4'-dihydroxy-3,3'-diphenylsulfone, 1,1-bis(4-hydroxyphenyl)methane, 1,1-bis(4-hydroxyphenyl)ethane, 2,2-bis(4-hydroxyphenyl)propane (commonly referred to as "BPA"), 1,1-bis(4-hydroxyphenyl)-1-phenylethane, 2,2-bis(4-hydroxy-3-methylphenyl)propane (commonly referred to as "BPC"), 9,9-bis(4-hydroxyphenyl)fluorene (hereinafter sometimes abbreviated as "BPF"), 9,9-bis(4-hydroxy-3-methylphenyl)fluorene fluorene (hereinafter sometimes abbreviated as "BCF"), 9,9-bis(4-hydroxy-3-phenylphenyl)fluorene (hereinafter sometimes abbreviated as "BPPF"), 2,2-bis(4-hydroxyphenyl)butane, 2,2-bis(4-hydroxyphenyl)pentane, 2,2-bis(4-hydroxy-3-phenylphenyl)propane, 2,2-bis(3-isopropyl-4-hydroxyphenyl)propane, 2,2-bis(3-t-butyl-4-hydroxyphenyl)propane, 2,2-bis(4-hydroxyphenyl)butane, 4,4-bis(4-hydroxyphenyl) Heptane, 2,2-bis(4-hydroxyphenyl)octane, 1,1-bis(4-hydroxyphenyl)decane, 1,1-bis(3-methyl-4-hydroxyphenyl)decane, 1,1-bis(2,3-dimethyl-4-hydroxyphenyl)decane, 2,2-bis(3-bromo-4-hydroxyphenyl)propane, bis(4-hydroxyphenyl)diphenylmethane, 1,1-bis(4-hydroxyphenyl)-4-isopropylcyclohexane, 2,2-bis(4-hydroxyphenyl)-1,1,1,3,3,3-hexafluoropropane (commonly known as "BPAF" (also referred to as 6,6'-dihydroxy-3,3,3',3'-tetramethyl-1,1'-spirobiindane, 7,7'-dimethyl-6,6'-dihydroxy-3,3,3',3'-tetramethyl-1,1'-spirobiindane, 7,7'-diphenyl-6,6'-dihydroxy-3,3,3',3'-tetramethyl-1,1'-spirobiindane, 2,2-bis(4-hydroxy-3-methylphenyl)-1,1,1,3,3,3-hexafluoropropane, 2,2-bis(3,5-dimethyl-4-hydroxyphenyl)-1,1,1,3,3,3-hexafluoropropane propane, 2,2-bis(3-fluoro-4-hydroxyphenyl)-1,1,1,3,3,3-hexafluoropropane, and 2,2-bis(3,5-difluoro-4-hydroxyphenyl)-1,1,1,3,3,3-hexafluoropropane, 2,2-bis(3,5-dibromo-4-hydroxyphenyl)propane, 2,2-bis(3,5-dichloro-4-hydroxyphenyl)propane, 2,2-bis(3,5-dimethyl-4-hydroxyphenyl)propane, and 2,2-bis(3-cyclohexyl-4-hydroxyphenyl)propane.

Of the above, BPM, TDP, HMPS, BPA, BPC, BPF, BCF, and BPPF are preferred.

Aliphatic diol compounds include 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-dodecanediol, 2-methyl-1,3-propanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, 2-n-butyl-2-ethyl-1, Examples include 3-propanediol, 2,2-diethyl-1,3-propanediol, 2,4-diethyl-1,5-pentanediol, 1,2-hexane glycol, 1,2-octyl glycol, 2-ethyl-1,3-hexanediol, 2,3-diisobutyl-1,3-propanediol, 2,2-diisoamyl-1,3-propanediol, and 2-methyl-2-propyl-1,3-propanediol.

Examples of alicyclic diol compounds include cyclohexanedimethanol, tricyclodecane dimethanol, adamantanediol, pentacyclopentadecanedimethanol, 2,2,4,4-tetramethyl-1,3-cyclobutanediol, and isosorbide (1,4;3,6-dianhydro-D-sorbitol).

(Method of producing polycarbonate resin polymer)
In the reaction using, for example, phosgene as a carbonate precursor, the reaction is usually carried out in the presence of an acid binder and a solvent. As the acid binder, for example, an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide or an amine compound such as pyridine is used. As the solvent, for example, a halogenated hydrocarbon such as methylene chloride or chlorobenzene is used. In addition, a catalyst such as a tertiary amine or a quaternary ammonium salt can be used to promote the reaction. In this case, the reaction temperature is usually 0 to 40°C, and the reaction time is several minutes to 5 hours.

The transesterification reaction using, for example, a carbonic acid diester as a carbonate precursor is carried out by heating and stirring a predetermined proportion of aromatic dihydroxy components with a carbonic acid diester under an inert gas atmosphere, and distilling off the resulting alcohol or phenol. The reaction temperature varies depending on the boiling point of the resulting alcohol or phenol, but is usually in the range of 120 to 300°C. The reaction is completed by reducing the pressure from the beginning and distilling off the resulting alcohol or phenol. In order to promote the reaction, a catalyst usually used in transesterification reactions can also be used. Examples of carbonic acid diesters used in the transesterification reaction include diphenyl carbonate, dinaphthyl carbonate, bis(diphenyl)carbonate, dimethyl carbonate, diethyl carbonate, and dibutyl carbonate. Of these, diphenyl carbonate is particularly preferred.

The polycarbonate resin of the present invention can be copolymerized with a fatty acid as necessary. Examples include 1,10-dodecanedioic acid, adipic acid, hexanedioic acid, isophthalic acid, 1,3-benzenedicarboxylic acid, terephthalic acid, 1,4-benzenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 3-hydroxybenzoic acid, and 4-hydroxybenzoic acid.

The polycarbonate resin of the present invention includes polyester carbonates copolymerized with aromatic or aliphatic (including alicyclic) bifunctional carboxylic acids. The aliphatic bifunctional carboxylic acids are preferably α,ω-dicarboxylic acids. Examples of the aliphatic bifunctional carboxylic acids include linear saturated aliphatic dicarboxylic acids such as sebacic acid (decanedioic acid), dodecanedioic acid, tetradecanedioic acid, octadecanedioic acid, and icosane diacid, as well as alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid. These carboxylic acids may be copolymerized to the extent that the purpose is not hindered. The polycarbonate resin of the present invention may also be copolymerized with a structural unit containing a polyorganosiloxane unit, if necessary.

The polycarbonate resin of the present invention can be made into a branched polycarbonate by copolymerizing a constituent unit containing a trifunctional or higher polyfunctional aromatic compound as required. Suitable examples of the trifunctional or higher polyfunctional aromatic compound used in the branched polycarbonate include trisphenols such as 4,6-dimethyl-2,4,6-tris(4-hydroxyphenyl)heptene-2, 2,4,6-trimethyl-2,4,6-tris(4-hydroxyphenyl)heptane, 1,3,5-tris(4-hydroxyphenyl)benzene, 1,1,1-tris(4-hydroxyphenyl)ethane, 1,1,1-tris(3,5-dimethyl-4-hydroxyphenyl)ethane, 2,6-bis(2-hydroxy-5-methylbenzyl)-4-methylphenol, and 4-{4-[1,1-bis(4-hydroxyphenyl)ethyl]benzene}-α,α-dimethylbenzylphenol. Of these, 1,1,1-tris(4-hydroxyphenyl)ethane is preferred. The content of the structural units derived from such polyfunctional aromatic compounds is preferably 0.03 to 1.5 mol %, more preferably 0.1 to 1.2 mol %, and particularly preferably 0.2 to 1.0 mol %, based on a total of 100 mol % including the structural units from other divalent components.

The branched structural unit may be derived not only from a polyfunctional aromatic compound, but also from a side reaction occurring during a polymerization reaction by a melt transesterification method without using a polyfunctional aromatic compound. The proportion of such branched structures can be calculated by ^1H -NMR measurement.

(Viscosity Average Molecular Weight)
The viscosity average molecular weight of the polycarbonate resin of the present invention is preferably 5,000 to 40,000, more preferably 8,000 to 30,000, further preferably 10,000 to 25,000, and particularly preferably 12,000 to 23,000. When it is in such a range, it is preferable because it has an excellent balance between moldability and mechanical strength.

The viscosity average molecular weight of the polycarbonate resin of the present invention is determined by first determining the specific viscosity (η _SP ) calculated by the following formula using an Ostwald viscometer from a solution in which 0.7 g of the resin is dissolved in 100 ml of methylene chloride at 20° C.:
Specific viscosity (η _SP )=(t−t ₀ )/t ₀
[ _t0 is the number of seconds that methylene chloride falls, and t is the number of seconds that the sample solution falls]
The viscosity average molecular weight Mv was calculated from the determined specific viscosity (η _SP ) according to the following formula.
η _SP /c = [η] + 0.45 × [η] ² c (where [η] is the intrinsic viscosity)
[η]=1.23×10 ⁻⁴ Mv ^0.83
c=0.7

(Glass transition temperature: Tg)
The glass transition temperature (Tg) of the polycarbonate resin is preferably 90 to 200° C., more preferably 100 to 190° C., and even more preferably 110 to 180° C. If the Tg is within the above range, the heat resistance stability and moldability are good when used as an optical molded body, which is preferable. The glass transition temperature (Tg) is measured using a 2910-type DSC manufactured by TA Instruments Japan Ltd. at a heating rate of 20° C./min.

(Amount of carboxyl groups)
The amount of carboxyl groups in the polycarbonate resin of the present invention is preferably 1 to 200 eq/ton, more preferably 10 to 170 eq/ton, further preferably 30 to 150 eq/ton, and particularly preferably 50 to 120 eq/ton. When the amount of carboxyl groups is equal to or more than the lower limit, the dispersion stability of inorganic fine particles under high temperature conditions is sufficient, and a transparent organic-inorganic hybrid composition can be obtained. When the amount is equal to or less than the upper limit, the molecular weight reduction of the polycarbonate resin can be suppressed, which has a favorable effect on the physical properties.

The amount of carboxyl groups in the present invention can be measured, for example, as follows. First, polycarbonate resin is dissolved in benzyl alcohol under a nitrogen atmosphere, and titrated with a benzyl alcohol solution of sodium hydroxide using phenol red as an indicator, and the amount of carboxyl groups is calculated from the amount of the solution dropped.

<Inorganic fine particles>
The inorganic fine particles used in the present invention are preferably modified with a surface modifier. The inorganic fine particles preferably have an average particle size in the nanoscale range of 20 nm or less.
Those modified with a surface modifying agent having an acidic functional group are preferably used.

Examples of types of inorganic fine particles include _ZrO2 (zirconium oxide), _TiO2 (titanium oxide), _SnO2 (tin oxide), _SiO2 (silicon oxide), _Al2O3 (aluminum oxide), etc. Among these, in the present invention, _ZrO2 and _TiO2 are preferred from the viewpoint of use as optical members and optical _components , and _ZrO2 is particularly preferred.

The surface modifier for inorganic fine particles in the present invention is not particularly limited as long as it can ensure the dispersibility of inorganic fine particles in the polycarbonate resin to be composited, but it is preferable to have an acidic functional group such as a sulfonic acid group, a phosphonic acid group, a phosphinic acid group, or a carboxylic acid group, as this provides excellent dispersibility and refractive index improvement effects. Representative examples of surface modifiers are shown below, but the surface modifier of the present invention is not limited to these. They may be used alone, or multiple types may be mixed and used. In particular, when dispersing inorganic fine particles after surface modification treatment in a resin, it is desirable to appropriately select and use a surface modifier that is likely to improve affinity with the resin depending on the type of resin.

Examples of sulfonic acids include alkyl sulfonic acids such as butanesulfonic acid, hexanesulfonic acid, and dodecanesulfonic acid, and aryl sulfonic acids such as benzenesulfonic acid, methylbenzenesulfonic acid, and dodecylbenzenesulfonic acid. Among these, aryl sulfonic acids are preferred in view of their dispersibility in resins and their effect of improving the refractive index.

Examples of phosphonic acids include alkyl phosphonic acids such as propane phosphonic acid, and aryl phosphonic acids such as benzene phosphonic acid. Among these, aryl phosphonic acids are preferred in view of their dispersibility in resins and their effect of improving the refractive index.

Examples of phosphinic acids include alkyl phosphinic acids such as dimethylphosphinic acid, diethylphosphinic acid, and di(2-ethylhexyl)phosphinic acid, and aryl phosphinic acids such as phenylphosphinic acid and diphenylphosphinic acid. In addition, by using thiophosphinic acid or dithiophosphinic acid in which the oxygen atoms constituting the phosphinic acid group are replaced with sulfur atoms, inorganic fine particles with a higher refractive index than when phosphinic acid is used can be obtained. Among these, in view of dispersibility in resin and the effect of improving the refractive index, arylphosphinic acids are preferred, phenylphosphinic acid and diphenylphosphinic acid are more preferred, and diphenylphosphinic acid is particularly preferred.

Examples of carboxylic acids include alkyl carboxylic acids such as butanoic acid, isobutanoic acid, methacrylic acid, hexanoic acid, octanoic acid, oleic acid, linoleic acid, and lauric acid, and aryl carboxylic acids such as benzoic acid, hydroxybenzoic acid, and phenoxybenzoic acid. In addition, by using thiocarboxylic acids and dithiocarboxylic acids in which the oxygen atoms constituting the carboxyl group of the carboxylic acid are replaced with sulfur atoms, inorganic fine particles with a higher refractive index than when carboxylic acids are used can be obtained. Among these, in view of dispersibility in resins and the effect of improving the refractive index, aryl carboxylic acids are preferred, and phenoxybenzoic acid having a phenoxy group at the ortho, meta, or para position is more preferred, and paraphenoxybenzoic acid is particularly preferred.

In the present invention, the surface modification of inorganic fine particles is carried out, for example, by the following process. That is, a surface modifier having an acidic functional group is added to a mixture of a transparent aqueous dispersion in which hydrophilic inorganic fine particles having an average particle size of about 20 nm or less are dispersed, and methanol, and then the water and methanol are removed by azeotropy and the solvent is replaced with toluene or methylene chloride to prepare a toluene dispersion or methylene chloride dispersion in which the surface-modified inorganic fine particles are dispersed. The solvent is then distilled off to obtain a white powder of the surface-modified inorganic fine particles.

In inorganic microparticles modified with a surface modifier, the content of the surface modifier is preferably 1 to 30% by mass, more preferably 3 to 28% by mass, and particularly preferably 5 to 25% by mass, relative to the inorganic microparticles, in consideration of dispersibility in resin and the effect of improving the refractive index. From the viewpoint of dispersibility in a resin composite, the higher the content of the surface modifier, the better, and from the viewpoint of the effect of improving the refractive index, the lower the content of the surface modifier, the better. It is desirable to adjust the content of the surface modifier appropriately according to the dispersibility and the desired refractive index.

<Components other than polycarbonate resin and inorganic fine particles>
The organic-inorganic hybrid composition of the present invention may contain, in addition to the polycarbonate resin and inorganic fine particles, functional agents known per se, such as a release agent, a heat stabilizer, an ultraviolet absorber, a flow modifier, and an antistatic agent, within the scope of not impairing the effects of the present invention.

The method for blending resins other than polycarbonate resin and additives into the organic-inorganic composite composition of the present invention is not particularly limited, and any known method can be used. The most commonly used method is to premix the polycarbonate resin, inorganic fine particles, and additives, then feed the mixture into an extruder for melt kneading, cool the extruded thread, and cut it with a pelletizer to produce a pellet-shaped molding material.

<Method of producing organic-inorganic composite composition>
The method for producing the organic-inorganic hybrid composition of the present invention includes obtaining a polycarbonate resin having a structure represented by the above formula (1) at a polymer chain terminal, and dispersing inorganic fine particles that have been surface-modified with a surface modifier in the polycarbonate resin.

The process for dispersing inorganic fine particles in polycarbonate resin is not particularly limited, but specific examples include a method of mixing a polycarbonate resin solution with an inorganic fine particle dispersion, and a method of melt-mixing a polycarbonate resin powder with an inorganic fine particle powder, and any of these methods may be used to prepare the dispersion.

For example, in a method of mixing a polycarbonate resin solution and an inorganic particle dispersion, the polycarbonate resin solution and the inorganic particle dispersion may be mixed all at once, or the polycarbonate resin solution may be gradually added dropwise to the inorganic particle dispersion and mixed. A plasticizer may also be present, and such a plasticizer may be added in advance to the resin solution or the inorganic particle dispersion, or may be added when the resin solution and the inorganic particle dispersion are mixed.

The content of inorganic fine particles in the organic-inorganic composite composition of the present invention is preferably 1 to 50% by mass, more preferably 3 to 40% by mass, and most preferably 5 to 30% by mass. If the surface-modified inorganic fine particles are less than the lower limit, it is difficult to obtain the effect of containing inorganic fine particles, and if the content exceeds the upper limit, the strength of the organic-inorganic composite decreases.

An organic-inorganic composite composition containing a polycarbonate resin having the structure represented by formula (1) at the polymer chain end and inorganic fine particles surface-modified with a surface modifier can also be added to another resin as a master resin and mixed for use. By using this method, it is possible to adjust the refractive index and Abbe number within any range and obtain an organic-inorganic composite composition suitable as an optical resin.

(Molding method)
The organic-inorganic composite composition of the present invention can be molded by injection molding, extrusion molding, compression molding, solution casting, or other general molding methods for polycarbonate resins. The organic-inorganic composite composition of the present invention has excellent transparency and high refractive index, and can be used as various molded articles. In particular, it can be advantageously used as a molded article suitable for structural materials for optical components such as optical lenses, optical disks, liquid crystal panels, optical cards, sheets, films, optical fibers, connectors, evaporated plastic reflectors, and displays, electrical and electronic components such as exteriors and front panels of personal computers and mobile phones, automotive applications such as automobile headlamps and windows, or functional material applications, and is particularly suitable for optical lenses and optical films.

(Average particle size)
In the organic-inorganic hybrid composition of the present invention, the inorganic fine particles have an average particle size of preferably 1 to 100 nm, more preferably 1 to 50 nm, and further preferably 1 to 20 nm. If the average particle size exceeds the upper limit of this range, the transparency of the organic-inorganic hybrid composition may be insufficient.

(Transmittance)
The organic-inorganic hybrid composition of the present invention preferably has high transmittance. The D-line transmittance of a molded article having a thickness of 1 mm is preferably 70% or more, and more preferably 80% or more. By satisfying such characteristics, the composition can be suitably used for optical lenses and optical films.

(Refractive Index)
The refractive index (hereinafter sometimes abbreviated as nD) of the organic/inorganic hybrid composition of the present invention at a wavelength of 589 nm measured at 25° C. is preferably 1.500 to 2.000. When the refractive index is equal to or higher than the lower limit, the spherical aberration of the lens can be reduced, and further the focal length of the lens can be shortened.

The present invention will be described in detail below with reference to examples, but the present invention is not limited thereto. In the examples, "parts" means "parts by mass." The polycarbonate resin, inorganic fine particles, and evaluation methods used in the examples are as follows.

<Evaluation method>
(Composition ratio)
Each repeating unit was measured by proton NMR using JNM-AL400 manufactured by JEOL Ltd., and the polymer composition ratio (molar ratio) was calculated.

(Viscosity Average Molecular Weight)
The specific viscosity (η _SP ) calculated by the following formula was determined using an Ostwald viscometer from a solution of 0.7 g of a sample dissolved in 100 ml of methylene chloride at 20° C.
Specific viscosity (η _SP )=(t−t ₀ )/t ₀
[ _t0 is the number of seconds that methylene chloride falls, and t is the number of seconds that the sample solution falls]
The viscosity average molecular weight Mv was calculated from the determined specific viscosity (η _SP ) according to the following formula.
η _SP /c = [η] + 0.45 × [η] ² c (where [η] is the intrinsic viscosity)
[η]=1.23×10 ⁻⁴ Mv ^0.83
c=0.7

(Glass Transition Temperature (Tg))
Using 8 mg of a sample, a thermal analysis system DSC-2910 manufactured by TA Instruments was used to perform the measurement in accordance with JIS K7121 under the conditions of a nitrogen atmosphere (nitrogen flow rate: 40 ml/min) and a temperature rise rate of 20° C./min.

(Amount of carboxyl groups)
The sample was dissolved in benzyl alcohol under a nitrogen atmosphere, and the content was calculated by titrating with a benzyl alcohol solution of sodium hydroxide using phenol red as an indicator.

(Moldability)
The pellets melted and kneaded in the extruder were molded by an injection molding machine (J-75E3 manufactured by Japan Steel Works) under conditions of a cylinder temperature of 300°C, a mold temperature of 80°C, a pressure holding time of 20 seconds, and a cooling time of 20 seconds to form a three-stage resin plate having a width of 50 mm, a length of 90 mm, and a thickness of 3 mm (length 20 mm), 2 mm (length 45 mm), and 1 mm (length 25 mm) from the gate side, and various evaluations were performed. When a three-stage resin plate was obtained under the above conditions, the moldability was evaluated as "◎", when a resin plate was obtained but a poor appearance such as the generation of bubbles occurred, the moldability was evaluated as "◯", and when the strength of the resin was insufficient due to hydrolysis or the like and a resin plate could not be obtained, the moldability was evaluated as "×".

(Average particle size)
The pellets melted and kneaded in the extruder were press molded in a hot press molding machine (compression molding machine: SFV-10, vacuum pump unit: GXD-360, manufactured by Shinto Metal Industries Co., Ltd.) to obtain a molded plate with a thickness of about 1 mm. The press molding conditions were a mold temperature of 220°C, a primary pressure of 1 MPa (30 seconds), and a secondary pressure of 1.5 MPa (5 minutes). This molded plate was cut to prepare ultrathin slices, which were attached to a grid (EM FINE GRID No. 2632 F-200-CU 100PC/CA, manufactured by JEOL Ltd.), and observed at an accelerating voltage of 200 kV using a transmission electron microscope TEM JEM-2100, manufactured by JEOL Ltd.
Using a micrograph at a magnification of 100,000 times, particle analysis was performed using image analysis software Win ROOF Ver. 6.6 (Mitani Shoji Co., Ltd.) to obtain the average size and particle size distribution (frequency distribution) of inorganic fine particles in the sample slice. Here, the maximum major axis (the length when any two points on the outer contour of the particle are selected so that the length between them is the maximum) was used as the size of each particle. The same analysis was performed on three sample slices, and the average value was used as the value for each sample.

(Transparency)
The three-stage resin plate obtained by injection molding was evaluated as having a spectral transmittance of 80% or more at 589 nm in a thickness of 1.0 mm, and as "good" if it was less than 80%.

(Refractive Index)
The refractive index (nD) (wavelength: 589 nm) of the three-stage resin plate obtained by injection molding at 25° C. was measured using an ATAGO DR-M2 Abbe refractometer.

<Production of polycarbonate resin>
(Production Example 1)
(Polymerization reaction)
A reactor equipped with a thermometer, a stirrer, and a reflux condenser was charged with 8,523 parts of ion-exchanged water and 3787 parts of 25% aqueous sodium hydroxide solution, and 901 parts of 2,2-bis(4-hydroxyphenyl)propane (hereinafter sometimes referred to as BPA) and 1,010 parts of 2,2-bis(4-hydroxy-3-methylphenyl)propane (hereinafter sometimes referred to as BPC) as dihydric phenols, and 5.73 parts of hydrosulfite were dissolved therein. Then, 6708 parts of methylene chloride was added, and 1,000 parts of phosgene (hereinafter sometimes abbreviated as "FH") was blown in over 70 minutes at 16 to 24°C under stirring. 631 parts of an aqueous 25% sodium hydroxide solution was added, and a solution of 58.2 parts of tertiary butyl 4-hydroxybenzoate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) dissolved in 580 parts of methylene chloride was added as a terminal terminator, and the mixture was stirred to an emulsified state, and then stirred vigorously again. With this stirring, 2.0 parts of triethylamine was added when the reaction solution was at 28°C, and the reaction was terminated by continuing stirring at a temperature of 26 to 31°C for 1 hour. After the reaction was completed, the organic phase was separated, diluted with methylene chloride and repeatedly washed with water, and when the washing solution became neutral, it was washed with acidic hydrochloric acid water. Thereafter, it was repeatedly washed with ion-exchanged water, and when the conductivity of the aqueous phase became almost the same as that of the ion-exchanged water, it was put into a kneader filled with warm water, and the methylene chloride was evaporated while stirring to obtain a resin powder. After dehydration, it was dried at 100°C for 12 hours in a hot air circulation dryer.

(Acid Modification Reaction)
500 parts of the resin powder was placed in a reactor equipped with a thermometer, a stirrer, and a reflux condenser, dissolved in 650 parts of methylene chloride, and 500 parts of trifluoroacetic acid (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was added over 30 minutes while stirring, and the reaction was terminated by continuing stirring at a temperature of 20 to 30°C for 5 hours. After the reaction was completed, the mixture was diluted with methylene chloride and repeatedly washed with ion-exchanged water until the conductivity of the aqueous phase became almost the same as that of the ion-exchanged water. The mixture was then placed in a kneader filled with warm water, and the methylene chloride was evaporated while stirring to obtain a resin powder. After dehydration, the mixture was dried at 100°C for 12 hours using a hot air circulation dryer. The viscosity average molecular weight of the obtained resin was 19,800, the glass transition temperature was 130°C, and the amount of carboxyl groups was 68 eq/ton.

(Production Example 2)
This was produced in the same manner as in Production Example 1, except that the dihydric phenol was changed to 1,988 parts of BPA, and the end terminators were changed to 54.1 parts of tert-butyl 4-hydroxybenzoate and 7,401 parts of methylene chloride.
(Acid Modification Reaction)
It was produced in the same manner as in Production Example 1. The viscosity average molecular weight of the resulting resin was 22,300, the glass transition temperature was 148° C., and the amount of carboxyl groups was 72 eq/ton.

(Production Example 3)
(Polymerization reaction)
This was produced in the same manner as in Production Example 1, except that the dihydric phenol was changed to 2,538 parts of 9,9-bis(4-hydroxy-3-phenylphenyl)fluorene (hereinafter sometimes referred to as BPPF) and 735 parts of 4,4'-dihydroxydiphenyl sulfide (hereinafter sometimes referred to as TDP), and the end terminator was changed to 83.3 parts of tert-butyl 4-hydroxybenzoate and 7,154 parts of methylene chloride.
(Acid Modification Reaction)
It was produced in the same manner as in Production Example 1. The viscosity average molecular weight of the resulting resin was 15,000, the glass transition temperature was 179° C., and the amount of carboxyl groups was 112 eq/ton.

(Production Example 4)
(Polymerization reaction)
A resin powder was obtained in the same manner as in Production Example 1, except that the dihydric phenol was changed to 901 parts of BPA and 1,010 parts of BPC, and the end terminator was changed to 40.2 parts of 2-allylphenol (manufactured by Tokyo Chemical Industry Co., Ltd.).
(Acid Modification Reaction)
In a reactor equipped with a thermometer, a stirrer, and a reflux condenser, 500 parts of the resin powder and 5,000 parts of 1,2-dichloroethane were added and dissolved, and then 117 parts of azobisisobutyronitrile (hereinafter AIBN) and 150 parts of 3-mercaptopropanoic acid were added, and the mixture was heated to 70°C under a nitrogen atmosphere and reacted for 4 hours. After the reaction was completed, the reaction solution was added to acetone to precipitate the polycarbonate resin, and the precipitate was collected by vacuum filtration. Next, the precipitate was dissolved in methylene chloride and added to acetone to precipitate the polycarbonate resin, and the precipitate was collected by vacuum filtration. The obtained precipitate was collected by vacuum filtration and dried to obtain a polycarbonate resin powder. The viscosity average molecular weight of the obtained resin was 20,300, the glass transition temperature was 136°C, and the amount of carboxyl groups was 58 eq/ton.

(Production Example 5)
(Polymerization reaction)
A resin powder was obtained in the same manner as in Production Example 1, except that the dihydric phenol was changed to 1,712 parts of BPA and 122 parts of 2,2-bis(3-allyl-4-hydroxyphenyl)propane (hereinafter referred to as BPDAL), and the end terminator was changed to 47.3 parts of p-tert-butylphenol.
(Acid Modification Reaction)
It was produced in the same manner as in Production Example 4. The viscosity average molecular weight of the resulting resin was 20,400, the glass transition temperature was 132° C., and the amount of carboxyl groups was 228 eq/ton.

(Production Example 6)
The resin was produced in the same manner as in Production Example 1 (polymerization reaction), except that the end terminator was changed to 45.0 parts of p-tert-butylphenol, and no acid modification reaction was carried out. The viscosity average molecular weight of the resulting resin was 20,000, and the glass transition temperature was 131° C.

(Production Example 7)
The resin was produced in the same manner as in Production Example 2 (polymerization reaction), except that the end terminator was changed to 41.8 parts of p-tert-butylphenol, and no acid modification reaction was carried out. The viscosity average molecular weight of the resulting resin was 22,000, and the glass transition temperature was 146°C.

(Production Example 8)
The resin was produced in the same manner as in Production Example 3 (polymerization reaction), except that the end terminator was changed to 64.4 parts of p-tert-butylphenol, and no acid modification reaction was carried out. The viscosity average molecular weight of the resulting resin was 15,200, and the glass transition temperature was 180° C.

<Production of inorganic fine particles>
(Production Example 9)
In a 2L eggplant flask equipped with a stirrer tip, 3.84 g of paraphenoxybenzoic acid was taken as a surface modifier, and 300 mL of methanol and 700 mL of chloroform were added and dissolved. Next, 37.2 of _ZrO2 aqueous dispersion (manufactured by Sakai Chemical Industry Co., Ltd.: SZR-W) was added dropwise over 15 minutes. The mixture was stirred at room temperature for 1 hour, and the solvent was distilled off to about 200 mL using a rotary evaporator. The distillation was performed by reducing the pressure to a level at which bumping did not occur in the liquid phase. 300 mL of methanol and 700 mL of chloroform were further added to the mixture to make a transparent dispersion with no interface again, and the solvent was distilled off again to about 200 mL. This operation was repeated three times to obtain a powdery solid.

500 mL of methylene chloride was added to the solid to make a transparent dispersion with no interface again, and the solvent was distilled off until the volume was about 100 mL. This operation was repeated three times to replace the water/methanol/chloroform mixed solvent with methylene chloride alone, obtaining a methylene chloride dispersion of ZrO2 _fine particles. Furthermore, this methylene chloride dispersion was vacuum dried at room temperature for 24 hours to remove the methylene chloride, and then further dried at 120°C for 48 hours to obtain a powder of surface-modified _ZrO2 .

(Production Example 10)
A surface-modified _ZrO2 powder was obtained in the same manner as in Production Example 9, except that 1.34 g of diphenylphosphinic acid was used as the surface modifier.

<Production of Organic-Inorganic Composite Composition>
[Examples 1 to 6, Comparative Examples 1 to 4]
The inorganic fine particles were dispersed in methylene chloride, and the methylene chloride solution of the polycarbonate resin was added dropwise over 5 minutes, followed by stirring for 30 minutes. This methylene chloride dispersion was dried at 80°C for 4 hours to remove the methylene chloride, and then further dried at 120°C for 24 hours to obtain flakes of the organic-inorganic composite. The flakes were melt-kneaded using a twin-screw extruder (KZW15-25MG manufactured by Technobel Co., Ltd.) at a cylinder and die temperature of 300°C, and the discharged resin was cut with a pelletizer while being cooled in a water tank to obtain pellets. The extruded pellets were molded using an injection molding machine (J-75E3 manufactured by Japan Steel Works) under conditions of a cylinder temperature of 300° C., a mold temperature of 80° C., a pressure holding time of 20 seconds, and a cooling time of 20 seconds to form a three-stage resin plate having a width of 50 mm, a length of 90 mm, and thicknesses of 3 mm (length 20 mm), 2 mm (length 45 mm), and 1 mm (length 25 mm) from the gate side. Various evaluations were performed, and the results are shown in Table 3. The types of resins used, the types of surface modifiers, and the amounts of inorganic fine particles added are as shown in Table 3.

As in Examples 1 to 6, when the polycarbonate resin of the present invention was used, an organic-inorganic composite composition with excellent moldability, transparency, and refractive index was provided. When a polycarbonate resin having carboxyl groups on the side chains but not at the polymer chain ends was used as in Comparative Example 1, decomposition was significant and melt moldability was poor. When a polycarbonate resin having no carboxyl groups at the polymer chain ends was used as in Comparative Examples 2 to 4, the inorganic fine particles could not be uniformly dispersed, the fine particles aggregated, and the transmittance was low.

Figure 1 shows a TEM image of the organic-inorganic composite composition obtained in Example 1. It was highly transparent and the inorganic particles were uniformly dispersed.

2 shows a TEM image of the organic-inorganic hybrid composition obtained in Comparative Example 3. The composition had low transparency and inorganic fine particles were aggregated.

The organic-inorganic composite composition of the present invention is excellent in terms of transparency, refractive index, and moldability. In addition, the refractive index and other properties can be adjusted as desired by adjusting the content of inorganic fine particles. Therefore, molded articles, films, and sheets obtained using the present invention can be used in a variety of fields.

Claims (13)

An organic-inorganic hybrid composition comprising a polycarbonate resin having a structural unit represented by the following formula (1) at a polymer chain end, and inorganic fine particles:
In formula (1), R ¹ and R ² may be independent or the same and represent at least one group selected from the group consisting of a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, a cycloalkyl group, a cycloalkoxy group, an alkenyl group, an aryl group, an aryloxy group, an aralkyl group, an aralkyloxy group, a nitro group, an aldehyde group, and a cyano group; a and b each represent an integer of 1 to 2; and X represents a group represented by the following formula (2):
In this case, ^R3 and ^R4 each independently represent at least one group selected from the group consisting of an alkylene group, an aralkylene group, an arylene group, and a cycloalkylene group, and a hydrogen atom in ^R4 may be substituted with a carboxyl group. The organic-inorganic composite composition according to claim 1, wherein the molar ratio of the polymer chain end is 1.0 mol% or more and 10 mol% or less relative to 100 mol% of all carbonate repeating units. The organic-inorganic hybrid composition according to claim 1 or 2, wherein the formula (1) includes a structural unit represented by the following formula (4):
(In formula (4), ^R7 represents at least one group selected from the group consisting of an alkylene group, an aralkylene group, an arylene group, and a cycloalkylene group.) 4. The organic-inorganic hybrid composition according to claim 1 , wherein the polycarbonate resin has a carboxyl group content of 1 eq/ton to 200 eq/ton. 5. The organic-inorganic hybrid composition according to claim 1 , wherein the surfaces of the inorganic fine particles are modified with a surface modifying agent. The organic-inorganic hybrid composition according to claim 5 , wherein the surface modifier has an acidic functional group. 7. The organic-inorganic hybrid composition according to claim 6 , wherein the acidic functional group is at least one acidic functional group selected from the group consisting of a sulfonic acid group, a phosphonic acid group, a phosphinic acid group, and a carboxylic acid group. 8. The organic-inorganic hybrid composition according to claim 5 , wherein the surfaces of the inorganic fine particles are modified with the surface modifying agent in an amount of 1 to 30% by mass based on the inorganic fine particles. The organic-inorganic hybrid composition according to any one of claims 1 to 8 , wherein the inorganic fine particles have an average particle size of 1 to 20 nm. The organic-inorganic hybrid composition according to any one of claims 1 to 9 , wherein the content of the inorganic fine particles is 1 to 50% by mass based on the polycarbonate resin. The organic-inorganic hybrid composition according to any one of claims 1 to ₁₀ , wherein the inorganic fine particles are at least one selected from the group consisting of _ZrO2 (zirconium oxide), _TiO2 (titanium oxide), _SnO2 (tin oxide), _SiO2 (silicon oxide), and _Al2O3 (aluminum oxide). A molded article obtained by using the organic/inorganic hybrid composition according to any one of claims 1 to 11 . A film or sheet obtained by using the organic/inorganic hybrid composition according to any one of claims 1 to 11 .