JP2022053373A - Resin composition - Google Patents

Abstract

To provide a resin composition which has a high refractive index ratio, is excellent in suppression of aggregation of metal oxide particles, and can be formed into a new optical material.SOLUTION: A resin composition contains metal oxide particles coated with a polymer material, and a binder resin, in which the polymer material and/or the binder resin contains a divalent aromatic hydrocarbon group that may have a substituent, contains a polymer having at least one structural unit selected from the group consisting of a structural unit (A) of -S-, a structural unit (B) of -S(=O)- and a structural unit (C) of -S(=O)2-, and has an element content ratio (O/S) of an oxygen atom O bonded to a sulfur atom S in a main chain to the sulfur atom S in the main chain of 0.1-1.5.SELECTED DRAWING: None

Description

The present invention relates to a resin composition. More specifically, the present invention relates to a resin composition having a high refractive index and excellent in suppressing aggregation of metal oxide particles.

As a high refractive index material, a polycarbonate having an aromatic ring and a polymer material having a fluorene skeleton are known. As a refractive index adjusting material for improving the light extraction efficiency of an LED and a lens material for an imaging system, a material having a large Abbe number, that is, a material having a small light dispersion is required. As a material having such a high refractive index and small light dispersion, a material into which sulfur molecules and halogen molecules have been introduced, a material containing metal oxide nanoparticles, and the like have been developed.

Various studies have been conducted on sulfur-containing polymer materials having a high refractive index and low light dispersion.
For example, Patent Document 1 describes a molding material having a polyarylene sulfide skeleton in which two hydrogen atoms of a benzene ring are substituted with a methyl group as a molding material which is excellent in moldability in a solution state and can be used as an optical member. Are listed.
Further, for example, in Patent Document 2, one hydrogen atom of a benzene ring is methyl as a molding material capable of forming an optical member having excellent moldability in a solution state and having a high refractive index exceeding 1.70. Molding materials having a polyarylene sulfide skeleton substituted with a group are described.

Japanese Unexamined Patent Publication No. 2015-168790 JP-A-2017-52834

However, it cannot be said that the conventional molding material has sufficiently high refractive index and visible light transparency, and there is still room for improvement. Further, in recent years, there has been a demand for a polymer material that can be used in a wide range of applications such as optical applications because it has characteristics such as high transparency and low linear expansion coefficient as well as high refractive index. .. A method of adding metal oxide particles having a high refractive index is known in order to realize a high refractive index, but when such particles are added to a conventional molding material, the particles are aggregated and molded. There are problems that the handleability of the material is lowered and the transparency of the molded product is lowered.

In view of the above situation, it is an object of the present invention to provide a resin composition which has a high refractive index and is excellent in suppressing aggregation of metal oxide particles and can be a new optical material.

As a result of various studies on sulfur-containing molding materials, the present inventor has found that a metal oxide particle coated with a polymer material and a binder resin are contained, and at least the polymer material or the binder resin is a sulfur-containing aromatic polymer. By including the composition, it has been found that the refractive index is extremely high, the metal oxide particles are excellent in suppressing aggregation, and the composition is useful as an optical material, and the present invention has been completed.

That is, the present invention is a resin composition containing a metal oxide particle coated with a polymer material and a binder resin, and the polymer material and / or the binder resin is represented by the following general formula (1). At least selected from the group consisting of the structural unit (A) represented, the structural unit (B) represented by the following general formula (2), and the structural unit (C) represented by the following general formula (3). It is a resin composition characterized by containing a polymer having one kind of structural unit.

(In the above general formulas (1) to (3), X ¹ , X ² and X ³ represent divalent aromatic hydrocarbon groups that may have the same or different substituents.)

The structural unit (A) is a structural unit (A-1) represented by the following general formula (1-1), and the structural unit (B) is represented by the following general formula (2-1). It is a structural unit (B-1), and the structural unit (C) is preferably a structural unit (C-1) represented by the following general formula (3-1).

(In formulas (1-1), (2-1) and (3-1), R ¹ , R ² and R ³ may have the same or different halogen atoms, hydroxyl groups, or substituents. It represents a good alkyl group, alkoxy group, aryl group, aralkyl group, or sulfur-containing substituent. A represents the number of R ¹ and is an integer of 0 to 4. b represents the number of R ² . It is an integer of 0 to 4. ^c represents a number of R3 and is an integer of 0 to 4.)

The polymer preferably has an element content ratio (O / S) of 0.1 to 1.5 between the oxygen atom O bonded to the sulfur atom S in the main chain and the sulfur atom S in the main chain.

The resin composition preferably further contains a compound having a (poly) styrene skeleton.

In the resin composition, it is preferable that the compound having the (poly) styrene skeleton and the metal oxide particles are covalently bonded.

The resin composition is preferably for optics.

According to the present invention, it is possible to provide a resin composition having a high refractive index and excellent suppression of aggregation of metal oxide particles. The resin composition of the present invention can be suitably used for optical applications such as image pickup lens materials.

It is a figure which showed the measurement data of the transmittance of the blend film obtained in Example 1. FIG. It is a photograph of the blend film obtained in Example 1.

The present invention will be described in detail below.
It should be noted that a combination of two or more of the individual preferred embodiments of the present invention described below is also a preferred embodiment of the present invention.

Resin Composition The resin composition of the present invention is a resin composition containing metal oxide particles coated with a polymer material and a binder resin, and the polymer material and / or the binder resin is described below. It is composed of a structural unit (A) represented by the general formula (1), a structural unit (B) represented by the following general formula (2), and a structural unit (C) represented by the following general formula (3). It is characterized by containing a polymer having at least one structural unit selected from the group.

（式（１）～（３）中、Ｘ^１、Ｘ^２及びＸ^３は、同一又は異なって、置換基を有してもよい２価の芳香族炭化水素基を表す。）

(In formulas (1) to (3), X ¹ , X ² and X ³ represent divalent aromatic hydrocarbon groups that may have the same or different substituents.)

The resin composition of the present invention has a high refractive index and is excellent in suppressing aggregation of metal oxide particles. It is presumed that the resin composition of the present invention has such characteristics because the metal oxide particles and the polymer material are uniformly compatible with each other and the aggregation of the particles can be suppressed.

The resin composition of the present invention contains metal oxide particles coated with a polymer material and a binder resin. In the resin composition, at least one of the polymer material and the binder resin contains a polymer having at least one structural unit selected from the group consisting of the structural units (A), (B) and (C). First, the polymer will be described.

<Polymer>
In the present invention, the polymer used as the polymer material and / or the binder resin is the structural unit (A) represented by the general formula (1) and the structural unit (B) represented by the general formula (2). ) And a polymer having at least one structural unit selected from the group consisting of the structural unit (C) represented by the general formula (3) (hereinafter, also referred to as “polymer (X)”). include.

In the above general formulas (1), (2) and (3), X ¹ , X ² and X ³ represent divalent aromatic hydrocarbon groups which may have the same or different substituents.
Examples of the divalent aromatic hydrocarbon group include a phenylene group, a naphthylene group, an anthrylene group, a triphenylene group, a biphenylene group, a phenanthrylene group and the like. Among them, the divalent aromatic hydrocarbon group is preferably a phenylene group, a naphthylene group, an anthrylene group, a biphenylene group, or a triphenylene group, and more preferably a phenylene group, in that the light dispersion becomes smaller. preferable.

The substituent (also referred to as "substituent A") contained in the divalent aromatic hydrocarbon group preferably has a halogen atom, a hydroxyl group, or a substituent (also referred to as "substituent B"). May include an alkyl group, an alkoxy group, an aryl group, an aralkyl group, or a sulfur-containing substituent.

Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, and among them, a bromine atom is preferable.

Examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an s-butyl group, a t-butyl group, a pentyl group, an isopentyl group, a neopentyl group, a hexyl group, and 2 -Methylpentyl group, 3-methylpentyl group, 2,2-dimethylbutyl group, 2,3-dimethylbutyl group, heptyl group and the like can be mentioned. Among them, an alkyl group having 1 to 18 carbon atoms is preferable, an alkyl group having 1 to 6 carbon atoms is more preferable, and a methyl group is further preferable.

Examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, an s-butoxy group, a t-butoxy group, a pentyloxy group, a phenoxy group, a cyclohexyloxy group, a benzyloxy group and the like. Of these, an alkoxy group having 1 to 18 carbon atoms is preferable, an alkoxy group having 1 to 6 carbon atoms is preferable, and a methoxy group is more preferable.

Examples of the aryl group include a phenyl group, a naphthyl group, an anthryl group, a biphenyl group, a triphenyl group and the like. Of these, a phenyl group is preferable. The aryl group preferably has 6 to 30 carbon atoms, more preferably 6 to 18 carbon atoms, and even more preferably 6 to 12 carbon atoms.

Examples of the aralkyl group include a benzyl group, a phenethyl group, a phenylpropyl group, a phenylpentyl group, a phenylhexyl group, a phenyloctyl group and the like. The carbon number of the aralkyl group is preferably 7 to 14, and more preferably 7 to 9.

Examples of the sulfur-containing substituent include a thioalkyl group and a thioaryl group. Of these, the thioalkyl group is preferable. The sulfur-containing substituent preferably has 1 to 8 carbon atoms, more preferably 1 to 6 carbon atoms, and even more preferably 1 to 4 carbon atoms.

The alkyl group, alkoxy group, aryl group, aralkyl group, and sulfur-containing substituent may further have a substituent (substituent B), and the substituent (substituent B) is an alkyl group. Examples thereof include a halogen atom and a hydroxyl group. Among them, an alkyl group is preferable from the viewpoint of solubility of a polymer material, and a halogen atom and a hydroxyl group are preferably mentioned from the viewpoint of dispersibility of metal oxide particles.

Among them, the substituent (substituent A) of the divalent aromatic hydrocarbon group is an alkyl group having 1 to 18 carbon atoms in that the refractive index of the resin composition can be further increased. , Sulfur-containing substituents are more preferred, methyl groups and thioalkyl groups are even more preferred, and methyl groups are particularly preferred.
Further, as the substituent (substituent A) of the divalent aromatic hydrocarbon group, a hydroxyl group or a sulfur-containing substituent is more preferable, and a hydroxyl group or a thioalkyl is preferable in that the dispersibility of the metal oxide particles can be improved. Groups and thioaryl groups are more preferable, and hydroxyl groups are particularly preferable.

The number of substituents A contained in the divalent aromatic hydrocarbon group is not particularly limited, but is preferably as small as possible in that the refractive index of the polymer material is further increased, and specifically, 1 to 6 thereof. Is more preferable, 1 to 3 is more preferable, and 1 is even more preferable.

The structural unit (A) is preferably a structural unit (A-1) represented by the following general formula (1-1).

(In the formula, R ¹ represents an alkyl group, an alkoxy group, an aryl group, an aralkyl group, or a sulfur-containing substituent which may have a halogen atom, a hydroxyl group, or a substituent, which may be the same or different. Represents the number of ^R1 and is an integer from 0 to 4.)

The structural unit (B) is preferably a structural unit (B-1) represented by the following general formula (2-1).

(In the formula, R ² represents an alkyl group, an alkoxy group, an aryl group, an aralkyl group, or a sulfur-containing substituent which may have a halogen atom, a hydroxyl group, or a substituent, which may be the same or different. Represents the number of R ² and is an integer from 0 to 4.)

The structural unit (C) is preferably a structural unit (C-1) represented by the following general formula (3-1).

(In the formula, R ³ represents an alkyl group, an alkoxy group, an aryl group, an aralkyl group, or a sulfur-containing substituent which may have a halogen atom, a hydroxyl group, or a substituent, which may be the same or different. ^Represents the number of R3 and is an integer from 0 to 4.)

The alkyl group, alkoxy group, aryl group, aralkyl group, and sulfur-containing substituent represented by R ¹ , R ² and R ³ which may have a substituent include the above general formula (1). Preferred examples thereof include an alkyl group, an alkoxy group, an aryl group, an aralkyl group, and a group similar to the sulfur-containing substituent described for X ¹ in the above.
Further, as the substituent that these groups may have, the same group as the above-mentioned substituent B is preferably mentioned.
When there are a plurality of R ¹ , R ² and R ³ above, they may be the same or different.

a, b, and c represent the number of substituents of R ¹ , R ² , and R ³ , respectively, and are integers of 0 to 4, preferably 0 to 3, and more preferably 0 to 2. It is an integer.

The polymer (X) may be an alternating copolymer of the structural units (A), (B) and (C), a block copolymer, or a random copolymer. There may be.
The polymer material may have one or more of the above structural units (A), (B), or (C), respectively.

The polymer (X) may be in a form containing only one of the structural units (A), (B) and (C), or in a form containing two structural units. It may be present, or it may be in a form including three structural units. These forms and their content ratios can be appropriately selected according to the purpose and use of the above resin composition.
For example, the polymer (X) preferably contains the structural unit (A), and more preferably contains it as a main component, in that it can have a higher refractive index.
Further, the polymer (X) preferably contains the structural unit (B), and more preferably contains it as a main component, in that it can achieve both solubility and a high refractive index.
Further, the polymer (X) preferably contains the structural unit (C), and more preferably contains it as a main component, in that transparency and a high refractive index can be compatible with each other.

From the above points, in the polymer (X), the content ratio of the structural unit (A) is 1 to 100 mol% with respect to 100 mol% of all the structural units of the polymer from the viewpoint of high refractive index. It is preferably present, more preferably 10 to 100 mol%, still more preferably 50 to 100 mol%.
In this case, the total content ratio of the structural unit (B) and the structural unit (C) is preferably 0 to 99 mol% and 0 to 90 mol% with respect to 100 mol% of all the structural units. Is more preferable, and 0 to 50 mol% is further preferable.

In the polymer (X), the content ratio of the structural unit (B) is 1 to 100 mol% with respect to 100 mol% of all the structural units of the polymer from the viewpoint of high polarity due to solubility. It is preferably 10 to 100 mol%, more preferably 50 to 100 mol%, and even more preferably 50 to 100 mol%.
In this case, the total content ratio of the structural unit (A) and the structural unit (C) is preferably 0 to 99 mol% and 0 to 90 mol% with respect to 100 mol% of all the structural units. Is more preferable, and 0 to 50 mol% is further preferable.

In the polymer (X), the content ratio of the structural unit (C) is preferably 1 to 100 mol% with respect to 100 mol% of all the structural units of the polymer from the viewpoint of high transparency. It is more preferably 10 to 100 mol%, still more preferably 50 to 100 mol%.
In this case, the total content ratio of the structural unit (A) and the structural unit (B) is preferably 0 to 99 mol% and 0 to 90 mol% with respect to 100 mol% of all the structural units. Is more preferable, and 0 to 50 mol% is further preferable.

In the polymer (X), the total content ratio of the structural units (A), (B) and (C) is 50 mol% or more with respect to 100 mol% of all the structural units of the polymer (X). It is more preferably 80 mol% or more, further preferably 90 mol% or more, further preferably 95 mol% or more, and particularly preferably 100 mol%.

The polymer (X) may have a structural unit (A), a structural unit (B), and a structural unit (D) other than the structural unit (C).
Examples of the structural unit (D) include structural units derived from the following monomers.
Carboxy group-containing (meth) acrylates such as 2-carboxyethyl (meth) acrylate, 2-carboxypropyl (meth) acrylate, 3-carboxypropyl (meth) acrylate, 4-carboxybutyl (meth) acrylate; 2 -Acrylic acid group-containing (meth) acrylate such as (meth) acryloyloxyethyl acid phosphate; epoxy group-containing (meth) acrylate such as glycidyl (meth) acrylate and 3,4-epoxycyclohexylmethyl (meth) acrylate; (meth) Vinyl ether group-containing (meth) acrylates such as 2- (2-vinyloxyethoxy) ethyl acrylate.

The content ratio of the structural unit (D) is preferably 0 to 80 mol%, more preferably 0 to 50 mol%, based on 100 mol% of all the structural units of the polymer (X). It is even more preferably 0 to 20 mol%, even more preferably 0 to 10 mol%, and particularly preferably 0 to 5 mol%.

The polymer (X) has an element content ratio (O / S) of the oxygen atom O bonded to the sulfur atom S of the main chain and the sulfur atom S of the main chain of 0.1 to 1.5. Is preferable. When the element content ratio is in the above range, the transparency and the refractive index become higher.
Specifically, the sulfur atom S in the main chain means the sulfur atom S of —S— in the main chain in the structural unit (A) represented by the general formula (1). Further, in the structural unit (B) represented by the general formula (2), it means the sulfur atom S of —SO— in the main chain, and in the structural unit (C) represented by the general formula (3). , Means the sulfur atom S of -SO _2- in the main chain.
The oxygen atom bonded to the sulfur atom S in the main chain is specifically, for example, the oxygen atom O of —SO— in the main chain in the structural unit (B) represented by the general formula (2). In the structural unit (C) represented by the above general formula (3), it means the oxygen atom O of _−SO2- on the main chain.

The element content ratio (O / S) is more preferably 0.3 or more, further preferably 0.7 or more, and further increase the refractive index in that the transparency can be further increased. It is more preferably 1.3 or less, and even more preferably 1.1 or less, in that it can be made even higher.
The element content ratio is measured by evaluating the peak intensities of the 1s orbital (O1s) of the oxygen atom, the 1s orbital (C1s) of the carbon atom, and the 2p orbital (S2p) of the sulfur atom using an X-ray photoelectron spectrometer (XPS). It can be obtained by doing.

The polymer (X) preferably has a glass transition temperature (Tg) of 80 to 250 ° C. When the glass transition temperature is in the above range, the molding process can be easily performed. The glass transition temperature is more preferably 90 ° C. or higher, further preferably 100 ° C. or higher, and 200 ° C. or lower from the viewpoint of facilitating molding processing, from the viewpoint of increasing heat resistance. Is more preferable.
The glass transition temperature is taken from the DSC curve obtained by raising the temperature from room temperature to 250 ° C. (heating rate 10 ° C./min) under a nitrogen gas atmosphere using a differential scanning calorimeter (DSC) as the baseline. It can be obtained by a method of evaluating by the intersection of tangents at the inflection point.

The polymer (X) preferably has an SO binding energy of 163 eV to 167 eV. When the binding energy of SO is in the above range, the refractive index and transparency can be further increased.
The SO binding energy can be obtained by evaluating the position of the peak top of the 2p3 / 2 orbital of the sulfur atom obtained by measuring by X-ray photoelectron spectroscopy (XPS).

The weight average molecular weight (Mw) of the polymer (X) is preferably 500 to 10000000. When the weight average molecular weight is in the above range, it can be suitably used as an optical material. The weight average molecular weight is more preferably 1000 or more, further preferably 3000 or more, still more preferably 10,000 or more, and 1,000,000 or less from the viewpoint of reducing melt viscosity. It is more preferable that it is 100,000 or less, and it is further preferable that it is 100,000 or less.

The degree of dispersion (weight average molecular weight / number average molecular weight) of the polymer (X) is preferably 1 to 10. When the degree of dispersion is in the above range, molding becomes easy. The dispersity is more preferably 5 or less, and even more preferably 3 or less, in that the moldability can be further improved.

The weight average molecular weight and the number average molecular weight can be obtained by measuring by a gel permeation chromatography (GPC) method, and specifically, can be obtained by the method described in Examples described later. The degree of dispersion can be determined by dividing the weight average molecular weight by the number average molecular weight.

The refractive index of the polymer (X) is preferably 1.69 or more. When the refractive index is within the above range, it is used for various purposes such as optical materials (members), mechanical parts materials, electrical / electronic parts materials, automobile parts materials, civil engineering and building materials, molding materials, as well as paints and adhesive materials. Can be suitably used for. The refractive index is more preferably 1.7 or more, and even more preferably 1.71 or more.
The refractive index is measured by forming a film having a thickness of 50 nm using the polymer as a measurement sample, using a spectroscopic ellipsometer UVISEL (manufactured by HORIBA Scientific), and using a Na D line (589 nm). Can be obtained by.

The Abbe number of the polymer (X) is preferably 10 or more. When the Abbe number is in the above range, the light dispersion is small and the optical material suitable for the lens can be obtained. The Abbe number is more preferably 15 or more, further preferably 18 or more, and even more preferably 20 or more. The Abbe number is preferably 60 or less, and more preferably 55 or less, from the viewpoint of adjusting the light dispersibility.
Similar to the refractive index, the Abbe number is formed by forming a film using the polymer, and using the spectroscopic ellipsometer, D line (589.3 nm), F line (486.1 nm), and C line (656 nm). The refractive index at (1.3 nm) can be measured and calculated using the following formula.
Abbe number (v _D ) = (n _D -1) / (n _F -n _C )
In the formula, n _D , n _F , and n _C represent the refractive indexes of Fraunhofer at the D line (589.3 nm), the F line (486.1 nm), and the C line (658.3 nm), respectively.

The polymer (X) preferably has a visible light transmittance of 70% or more. When the visible light transmittance is in the above range, it can be suitably used as an optical material. The visible light transmittance is more preferably 80% or more, more preferably 85% or more, and further preferably 88% or more.
The visible light transmittance is a parallel line transmittance, and a spectrophotometer (for example, Japan) by using a thin film having a thickness of 0.02 mm made of the polymer or by standardizing the thickness to 0.02 mm. It can be obtained by measuring the range of 400 nm to 700 nm in an air object without using an integrating sphere with a spectroscopic ultraviolet-visible-infrared spectrophotometer V-700 series) and evaluating the lowest value of transmittance. ..

The polymer (X) preferably has a linear expansion coefficient of 100 ppm / ° C. or less. When the linear expansion coefficient of the polymer is in the above range, the optical material has a small temperature dependence of the refractive index, and can be suitably used for various applications such as optical materials, encapsulants, and coating materials. The coefficient of linear expansion is more preferably 60 ppm / ° C. or lower, and even more preferably 30 ppm / ° C. or lower, in that the temperature dependence can be further reduced. The lower limit of the linear expansion coefficient is not particularly limited, but is preferably 1 ppm / ° C. or higher, and more preferably 3 ppm / ° C. or higher.
The coefficient of linear expansion can be measured and obtained by a method according to JIS K 7197: 2012.

The polymer (X) is preferably thermoplastic. When the polymer is thermoplastic, the inclusion of the binder resin made of the polymer improves the moldability such that a thin film can be uniformly formed and a complicated shape can be formed with high accuracy, and is suitable for a wide range of applications. Is easy to apply.

(Method for producing polymer (X))
The method for producing the polymer (X) is not particularly limited as long as it can produce a polymer having at least one of the above-mentioned structural units (A) to (C), and the sulfur-containing single amount. It is preferable to carry out by a known polymerization method such as polymerizing a monomer component containing a body. Among them, in that the polymer can be efficiently produced, the method for producing the polymer is a step of polymerizing a monomer component containing a sulfur-containing monomer to obtain a sulfur-containing polymer (1). It is preferable to include the step (2) of oxidizing the sulfur-containing polymer using an oxidizing agent.

Process (1)
The sulfur-containing monomer used in the step (1) is not particularly limited as long as it is a monomer containing a sulfur atom, but in the production method of the present invention, the sulfur-containing monomer is oxidatively polymerized. It is preferable to obtain a sulfur-containing polymer. Preferred examples of the sulfur-containing monomer from which a sulfur-containing polymer can be obtained by oxidative polymerization include a disulfide compound and a thiol compound. Specifically, for example, a diaryl represented by the following general formula (4). More preferably, a disulfide compound and a thioaryl compound represented by the following formula (5) are mentioned.

In the above general formulas (4) and (5), A ¹ and A ² represent monovalent aromatic hydrocarbon groups which may have the same or different substituents.
As the monovalent aromatic hydrocarbon group represented by A ¹ and A ² , for example, a divalent aromatic hydrocarbon group represented by X ¹ in the above general formula (1) is monovalent. Examples thereof include a phenyl group, a naphthyl group, an anthryl group, a triphenyl group, a biphenyl group, a phenanthryl group and the like. Among them, a phenyl group, a naphthyl group, an anthryl group, a biphenyl group, or a triphenyl group is preferable, and a phenyl group is more preferable.

Examples of the substituent contained in the monovalent aromatic hydrocarbon group represented by A ¹ and A ² include a halogen atom, an alkyl group, an alkoxy group, an aryl group, an aralkyl group, and a sulfur-containing substituent. Examples of the halogen atom, alkyl group, alkoxy group, aryl group, aralkyl group, and sulfur-containing substituent include the same groups as the above-mentioned groups.

The diallyl disulfide compound is preferably a compound represented by the following general formula (4-1).
The thioaryl compound is preferably a compound represented by the following general formula (5-1).

(In formulas (4-1) and (5-1), R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ and R ¹¹ are the same or different, and are hydrogen atom and halogen atom. , Or an alkyl group, an alkoxy group, an aryl group, an aralkyl group, or a sulfur-containing substituent which may have a substituent.)
The above-mentioned halogen atom or an alkyl group, an alkoxy group, an aryl group, an aralkyl group, or a sulfur-containing substituent which may have a substituent is represented by R ¹ in the above-mentioned general formula (1-1), respectively. It is similar to each group to be made.
Examples of the substituent that these groups may have include the same as the above-mentioned substituent B, and among them, a halogen atom and a hydroxyl group are preferable.

The disulfide compound can also be prepared by oxidizing a thiol compound. Therefore, in the polymerization step, a thiol compound can also be used as a precursor of the disulfide compound. A disulfide compound can be obtained by oxidatively binding two molecules of a thiol compound.

The method for obtaining the disulfide compound by oxidizing the thiol compound is not particularly limited, and a known method such as a method for oxidizing with hydrogen peroxide, iodine or the like can be used.

Only one type of the sulfur-containing monomer may be used, or two or more types may be used.

The above polymerization is preferably oxidative polymerization. The oxidative polymerization is not particularly limited, and can be carried out by a known method such as a method using a quinone compound or a method using a metal compound such as a vanadium compound. Above all, it is preferable that the oxidative polymer is carried out by using a quinone-based oxidizing agent because the transparency can be improved. It is preferable to use a metal compound in that the amount used for the monomer component is small and the amount of waste is small.

Examples of the quinone-based oxidizing agent include 2,3-dichloro-5,6-dicyano-parabenzoquinone (DDQ), 2,3,5,6-tetrachloroparabenzoquinone (chloranyl), 2,3,5. 6-Tetrabromobenzoquinone (bromanyl), 2,3,5,6-tetrafluoroparabenzoquinone, anthraquinone, 1,4-naphthoquinone, 2,3-dichloro-1,4-naphthoquinone, 2,3-dibromo-1, 4-Naphthoquinone, 2,3-dicyano-1,4-naphthoquinone, 3,4,5,6-tetrachloroorthobenzoquinone (orthochloranyl), 3,4,5,6-tetrabromoortobenzoquinone (orthobromanyl), 3 , 4, 5, 6-Tetrafluorobenzoquinone and the like. Among them, DDQ is preferable because of its high oxidizing power and easy availability. Only one kind of the above-mentioned quinone-based oxidizing agent may be used, or two or more kinds thereof may be used.

The amount of the quinone-based oxidizing agent added is preferably 0.1 to 3 mol, more preferably 0.8 to 1.5 mol, based on 1 mol of the sulfur-containing monomer used. It is more preferably 0.9 to 1.1 mol.

When using the above quinone-based oxidizing agent, an acid may be further added. When the above quinone-based oxidizing agent acts, the quinone-based compound becomes a hydroquinone dianion, but when an acid is added, the quinone can be stabilized and the oxidizing power can be maintained.

The acid is not particularly limited, and is, for example, sulfuric acid, acetic acid, methanesulfonic acid, benzenesulphonic acid, toluenesulphonic acid, trifluoromethanesulphonic acid, 1,1,2,2-tetrafluoroethanesulphonic acid, trifluoroacetic acid. , Perfluoropropionic acid, perfluorobutyric acid and the like. Of these, trifluoroacetic acid is preferable in terms of increasing acidity. Only one kind of the above acid may be used, or two or more kinds may be used.

The amount of the acid added is preferably 10 to 1000 mol, more preferably 50 to 500 mol, and 80 to 120 mol with respect to 100 mol of the total amount of the quinone-based oxidizing agent to be added. Is more preferable.

The reaction temperature is not particularly limited as long as it is a temperature at which the polymerization proceeds, but it is preferably 0 to 200 ° C., more preferably 10 ° C. or higher, and further preferably 15 ° C. or higher, because the above-mentioned oxidative polymerization is likely to proceed. It is preferable, and 180 ° C. or lower is more preferable, and 150 ° C. or lower is further preferable, because side reactions can be suppressed.

The reaction time is not particularly limited, but is usually 0.1 to 100 hours, preferably 1 to 80 hours, more preferably 5 to 50 hours, and further preferably 10 to 24 hours. preferable.

In the above polymerization reaction, a solvent may be used. Preferred solvents include, for example, dichloromethane, chloroform, carbon tetrachloride, 1,2-dichloroethane, tetrachlorethylene, 1,1,2,2-tetrachloroethane, nitromethane, nitrobenzene, chlorobenzene, 1,2-dichlorobenzene, 1,3. -Dichlorobenzene, N-methylpyrrolidone, tetrahydrofuran, ethyl acetate and the like can be mentioned.

In the above polymerization reaction, a monomer component containing a sulfur-containing monomer may be sequentially added during the polymerization reaction.
Further, after the above-mentioned thiol compound is oxidatively polymerized to obtain a disulfide compound, the obtained disulfide compound may be oxidatively polymerized and then polymerized in multiple stages.

Process (2)
After the step (1), an oxidizing agent is used to oxidize the sulfur-containing polymer.
The oxidizing agent to be used is not particularly limited, and known ones can be used, for example, quinone compounds, perbenzoic acid, metachloroperbenzoic acid, lead tetraacetate, tallium acid acetate, tetracyanoquinodimethane. , Tetracyanoquinodimethane, cerium (IV) acetylacetonate, manganese (III) acetylacetonate, peroxide, chloric acid and the like.

In particular, in order to oxidize the sulfur atom (-S-) contained in the main chain to sulfonyl (-SO _2- ), it is preferable to use a peroxide or chloric acid as an oxidizing agent. On the other hand, in order to obtain sulfinyl (-SO-), it is preferable to use a peroxide or chloric acid as an oxidizing agent.

Examples of the peroxide include metachloroperbenzoic acid, hydrogen peroxide, ammonium persulfate, sodium persulfate, peracetic acid, t-butyl hydroperoxide and the like.
Among them, the oxidizing agent is preferably a peroxide, and may be metachloroperbenzoic acid or hydrogen peroxide, in that it can be dissolved in the same solvent as the solvent capable of dissolving the sulfur-containing polymer. More preferred. The above-mentioned oxidizing agent is more preferably metachloroperbenzoic acid in terms of not using water in which the polymer precipitates and in terms of suppressing oxidation of sulfoxide with an excess oxidizing agent.

The amount of the oxidizing agent added is not particularly limited as long as the desired oxidation reaction of sulfur atoms proceeds, but is usually 0.1 to 10 mol with respect to 1 mol of sulfur atoms in the sulfur-containing polymer. It is preferably 0.5 to 5 mol, more preferably 0.8 to 1.5 mol, and even more preferably 0.8 to 1.5 mol.

The reaction temperature of the oxidative reaction is not particularly limited as long as it is a temperature at which the desired oxidative reaction proceeds, but it is preferably 0 to 200 ° C., more preferably 10 ° C. or higher, because the oxidative reaction is likely to proceed. It is preferably 15 ° C. or higher, more preferably 180 ° C. or lower, still more preferably 150 ° C. or lower in terms of suppressing side reactions.

The reaction time is not particularly limited, but is usually 0.1 to 100 hours, preferably 1 to 80 hours, more preferably 5 to 50 hours, and further preferably 10 to 24 hours. preferable.

A solvent may be used in the oxidation reaction of the step (2), and as the solvent, the same solvent as the solvent used in the polymerization step of the step (1) can be preferably mentioned.

It is preferable to wash the polymer obtained in the above step (2) because acids and the like may remain. The cleaning method is not particularly limited, and examples thereof include a method of cleaning with water, an acid, a base, or the like. Further, in order to remove the unreacted substance, the polymer may be filtered or washed with a solvent. The solvent is not particularly limited, but the same solvent as the reaction solvent can be used.

In the method for producing the polymer (X), other steps may be included in addition to the steps (1) and (2). Examples of the other steps include an aging step, a neutralization step, a dilution step, a drying step, a concentration step, a purification step, and the like. These steps can be performed by a known method.

<Metal oxide particles coated with polymer material>
The metal oxide particles coated with the polymer material are particles in a state in which the polymer material adheres to a part or all of the surface of the metal oxide particles to form a coating layer. The above-mentioned adhesion represents a state in which the surface of the metal oxide particles and the polymer material are bonded by a covalent bond. Such a bonded state can be confirmed, for example, by separating from the metal oxide particles when extracted and washed with a solvent.
From the viewpoint of preventing aggregation of the metal oxide particles, it is preferable that the entire surface of the metal oxide particles is coated with a polymer material.

The thickness of the coating layer is preferably 0.1 to 100 nm, more preferably 1 to 20 nm, and more preferably 1 to 10 nm from the viewpoint of high refraction and dispersibility in the resin. More preferred. The thickness of the coating layer can be measured and obtained by a method of thermal decomposition by TGA. Further, it is possible to estimate the film thickness of the coating film by comparing FE-SEM and TEM.

The amount (coating amount) of the coating layer is preferably 0.1 to 500% by mass with respect to 100% by mass of the metal oxide particles coated with the polymer material, and is preferably 5 to 100% by mass. Is more preferable, and 10 to 50% by mass is further preferable.
The content of the coating layer can be determined by measuring by thermogravimetric differential thermal analysis (TG-DTA).

(Metal oxide particles)
The metal oxide particles coated with the polymer material include a single metal oxide composed of one kind of metal element, a composite oxide which is an oxide composed of two or more kinds of metal elements, and the single metal oxidation. Examples thereof include particles of a solid solution oxide in which a dissimilar element is solid-dissolved in a substance or the above-mentioned composite oxide. The dissimilar element may be a metal element or a non-metal element such as nitrogen or fluorine other than oxygen.
Examples of the metal element include lithium (Li), sodium (Na), potassium (K), magnesium (Mg), calcium (Ca), manganese (Mn), strontium (Sr), barium (Ba), and titanium (Ti). , Zirconium (Zr), Iron (Fe), Cobalt (Co), Nickel (Ni), Copper (Cu), Zinc (Zn), Aluminum (Al), Tin (Sn), Silicon (Si), Strontium (Se) , Indium (In) and the like.

Examples of the single metal oxide include magnesium oxide, calcium oxide, strontium oxide, barium oxide, titanium oxide, zinc oxide, cerium oxide, silicon oxide, tin oxide, zirconium oxide, aluminum oxide, indium oxide and the like. ..
Examples of the composite oxide include perovskite-type composite oxides such as barium titanate, barium strontium titanate, strontium titanate, barium titanate strontium titanate, barium titanate zirconium, and lead zircate titanate; spinel, lithium titanate, and the like. Spinel-type composite oxide; Composite oxides such as aluminum titanate can be mentioned.
Examples of the solid solution oxide include solid solution oxides in which a dissimilar metal element and / or a non-metal element other than oxygen, for example, nitrogen or fluorine is solid-dissolved in the single metal oxide or composite oxide.
Only one kind of these metal oxide particles may be used, or two or more kinds of these metal oxide particles may be used in combination.

Among them, particles of zirconium oxide, titanium oxide, or silicon dioxide are more preferable in terms of further improving transparency and low linear expansion of the resin composition, and refraction of the resin composition. From the viewpoint of improving the rate, zirconium oxide or titanium oxide particles are more preferable. Further, perovskite-type oxide particles are preferable in that they have a high relative permittivity and the resin composition can be suitably used as a ferroelectric material or a piezoelectric material. Boron nitride, aluminum hydroxide, and aluminum titanate particles are preferable in that they have high thermal conductivity and the resin composition can be suitably used as a heat dissipation material.

Further, since the metal oxide particles do not absorb or have little absorption in the visual light region, it is easy to obtain a colorless and transparent composition in which coloring by an inorganic substance is suppressed, and Ti, Zr, Ce, Zn. , In, Al, Si, and Sn are more preferable as oxide particles containing metal elements as main components, and of titanium oxide, zirconium oxide, cerium oxide, zinc oxide, indium oxide, aluminum oxide, silicon oxide, and tin oxide. It is more preferably particles.

The shape of the metal oxide particles is not particularly limited, and may be, for example, an indefinite shape, a spherical shape, a plate shape, a rod shape, a polyhedral shape, or the like.

The average particle size of the metal oxide particles is preferably 1 nm or more and 1000 nm or less. When the average particle size of the metal oxide particles is in the above range, the transparency in the visible light region and the infrared region can be improved. The average particle size of the metal oxide particles is more preferably 5 nm or more, further preferably 10 nm or more, still more preferably 100 nm or less, still more preferably 50 nm or less.
The average particle size is about 10 to 1000 individual particles (about 10 to 1000 times) by observing the metal oxide with SEM (magnification: 1,000 to 100,000 times, preferably 10,000 times) and analyzing the obtained image. It is obtained by determining the particle size (diameter equivalent to the circular area) of the primary particles) and evaluating the 50% particle size based on the number-based particle size distribution. For image analysis, known image analysis software (for example, Mac-View manufactured by Mountech) can be used.

The content of the metal oxide particles coated with the polymer material can be appropriately set according to the purpose and application of the resin composition, but usually, the total solid content of the resin composition is 100% by mass. On the other hand, it is preferably 5 to 95% by mass. The content of the metal oxide particles is more preferably 20% by mass or more, and more preferably 40% by mass or more, based on 100% by mass of the total solid content of the resin composition in terms of high refraction. Further, it is more preferably 60% by mass or more, further preferably 90% by mass or less, and further preferably 80% by mass or less from the viewpoint of transparency.

(Preparation of metal oxide particles coated with polymer material)
The method of coating the metal oxide particles with the above-mentioned polymer material is not particularly limited, and a known method can be used. For example, a method using a silane coupling agent or a method of reacting a compound having a phosphoric acid group. , A method of reacting a carboxylic acid group or the like is used, and among them, a method of coating the metal oxide particles with the above-mentioned polymer material by using a silane coupling agent is preferable.

As a method of using the above-mentioned silane coupling agent, for example, a method of surface-treating the metal oxide particles using the silane coupling agent and then reacting the surface-treated metal oxide particles with the polymer material is used. Can be mentioned.

The silane coupling agent is not particularly limited, and a known silane coupling agent can be used, but among them, a silane coupling agent having a halogen atom, a vinyl group, an acrylic group, and a methacryl group is preferable. A silane coupling agent having an atomic or vinyl group is more preferable.

The silane coupling agent having a halogen atom can be prepared by reacting a silane compound having a group capable of reacting with an acid group with a compound having an acid group and a halogen atom.
Preferred examples of the group capable of reacting with the acid group include an epoxy group and the like.
Preferred examples of the acid group include a carboxyl group, a phosphoric acid group, and a sulfo group.

In the surface treatment, the amount of the silane coupling agent used is preferably 0.1 to 1000 parts by mass, more preferably 1 to 100 parts by mass with respect to 100 parts by mass of the metal oxide particles. It is more preferably 10 to 80 parts by mass.

In the above surface treatment, the treatment temperature is preferably 0 to 150 ° C, more preferably 10 to 100 ° C. The treatment time is preferably 1 to 100 hours, more preferably 1 to 24 hours.

In the reaction between the surface-treated metal oxide particles and the polymer material, the amount of the polymer material used is 1 to 10,000 parts by mass with respect to 100 parts by mass of the surface-treated metal oxide particles. It is preferably 10 to 1000 parts by mass, and more preferably 10 to 1000 parts by mass.

In the reaction between the surface-treated metal oxide particles and the polymer material, the reaction temperature is preferably 0 to 150 ° C, more preferably 10 to 120 ° C.
The reaction time is not particularly limited, but is preferably 1 to 100 hours, more preferably 1 to 48 hours.

The surface treatment step and the reaction step may be carried out in a solvent. The solvent used is not particularly limited, and is, for example, an alcohol solvent such as methanol, ethanol, propanol, butanol, and propylene glycol monomethyl ether; a ketone solvent such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ethyl acetate, acetic acid. Ester-based solvents such as isopropyl, butyl acetate and γ-butyrolactone; ether-based solvents such as diethyl ether, diisopropyl ether, 1,2-dimethoxyethane (DME) and tetrahydrofuran (THF); aromatic hydrocarbon-based solvents such as toluene and xylene. Solvents: Halogenated hydrocarbon solvents such as chlorobenzene, fluorobenzene, dichloromethane, chloroform, carbon tetrachloride, 1,2-dichloroethane, benzotrifluoride; amides such as dimethylformamide (DMF), dimethylacetamide, N-methylpyrrolidone Solvent: One or more of dimethyl sulfoxide (DMSO), nitromethane and the like.

In the above-mentioned surface treatment step and reaction step, additives used in a normal surface treatment step or reaction step such as a catalyst may be further used. The types and amounts of these may be appropriately set from known techniques.

After the above reaction, if necessary, the metal oxide particles whose surface is coated with the above-mentioned polymer material can be obtained through an arbitrary step such as a washing step and a solvent removing step. The cleaning step and the solvent removing step can be performed by a known method.

In the reaction step between the surface-treated metal oxide particles and the polymer material, the polymer material is formed in the presence of the surface-treated metal oxide particles instead of using the polymer material. It may be a step of polymerizing a monomer component for this purpose. Even in such a method, metal oxide particles coated with a polymer material can be prepared.

The above-mentioned polymerization step may be appropriately selected from known polymerization methods according to the monomer component to be used and the like. Further, in the above-mentioned polymerization step, commonly used known additives such as an initiator, a catalyst, and a solvent can be appropriately used.

<Binder resin>
The resin composition of the present invention further contains a binder resin.
As described above, the binder resin preferably contains the polymer (X).
As the binder resin, one kind of the above polymer (X) may be used, or two or more kinds of the above polymer (X) may be used.
Further, the polymer (X) used as the binder resin may be the same as or different from the polymer (X) used as the polymer material.

The content of the binder resin can be appropriately set according to the purpose and use of the resin composition, but is 1 to 1000% by mass with respect to 100% by mass of the total solid content of the resin composition. Is preferable. The content of the binder resin is more preferably 10% by mass or more, more preferably 30% by mass or more, based on 100% by mass of the total solid content of the resin composition, in that flexibility and crack resistance can be imparted. It is more preferably 500% by mass or less, and further preferably 200% by mass or less.

<Compound with (poly) styrene skeleton>
The resin composition of the present invention preferably further contains a compound having a (poly) styrene skeleton (hereinafter, also referred to as “compound (Y)”). The compound having the (poly) styrene skeleton can be used as the above-mentioned polymer material or binder resin other than the above-mentioned polymer (X). For example, in the resin composition of the present invention, the polymer (X) is used as the polymer material, and the compound having the (poly) styrene skeleton is used as the binder resin, or the polymer material. As described above, a compound having a (poly) styrene skeleton is used, and the polymer (X) is used as the binder resin, or the polymer (X) is used as both the polymer material and the binder resin. There is a form to use. In particular, in terms of high refraction, it is preferable to use the polymer (X) as both the polymer material and the binder resin.

The compound (Y) having the (poly) styrene skeleton is a compound having a structure represented by the following general formula (6).

(In the formula, R ¹² , R ¹³ and R ¹⁴ represent the same or different hydrogen atom or methyl group. R ¹⁵ , R ¹⁶ and R ¹⁷ , R ¹⁸ and R ¹⁹ are the same or different. Represents a hydrogen atom, an alkyl group, or an alkoxy group.)

In the formula, the alkyl groups represented by R ¹⁵ , R ¹⁶ , R ¹⁷ , R ¹⁸ and R ¹⁹ may be linear, branched or cyclic, but linear or branched chains are preferable. .. The number of carbon atoms of the alkyl group is preferably 1 to 18, more preferably 1 to 8, and even more preferably 1 to 3.

In the formula, the alkoxy group represented by R ¹⁵ , R ¹⁶ , R ¹⁷ , R ¹⁸ and R ¹⁹ preferably has 1 to 18 carbon atoms, more preferably 1 to 8 carbon atoms, and more preferably 1 to 8 carbon atoms. It is more preferably 1 to 3.

Specific examples of the compound (Y) include compounds such as styrene, α-methylstyrene and 4-methylstyrene, and polymers thereof. Of these, (poly) styrene is preferable because it has good compatibility with the polymer (X).

The compound (Y) preferably has a number average molecular weight of 500 to 30000000, more preferably 1000 to 100,000, and more preferably 2000 to 10000, in that the compatibility with the polymer (X) becomes high. It is more preferable to have.
The compound (Y) preferably has a dispersity (Mw / Mn) of 1 to 10, more preferably 1 to 5, and even more preferably 1 to 2.
The number average molecular weight and the degree of dispersion can be obtained by the same method as the method for measuring the molecular weight of the polymer (X) described above.

The glass transition temperature (Tg) of the compound (Y) is preferably 80 to 250 ° C, preferably 90 ° C or higher, further preferably 100 ° C or higher, and more preferably 200 ° C or lower. More preferably, it is 180 ° C. or lower.
The glass transition temperature can be determined by the same method as the glass transition temperature of the polymer (X) described above.

In the case of the resin composition containing the compound (Y), the compound (Y) is preferably covalently bonded to the metal oxide particles. In this case, the compound (Y) is used as the polymer material for coating the metal oxide particles.
The covalent bond between the compound (Y) and the metal oxide particles shall be confirmed by the same method as the method for confirming the state in which the metal oxide particles are coated with the polymer material. Can be done.

The content of the compound (Y) is preferably the content of the polymer material when the compound (Y) is used as the polymer material. When the compound (Y) is used as the binder resin, the content of the binder resin is preferably the above-mentioned content.

<Other ingredients>
In addition to the above-mentioned components, the above-mentioned resin composition includes, for example, resins other than those described above, pigments, dyes, antioxidants, ultraviolet absorbers, reactive diluents, photostabilizers, plasticizers, non-reactive compounds, and the like. Chain transfer agent, thermal polymerization initiator, anaerobic polymerization initiator, polymerization inhibitor, inorganic filler, organic filler, adhesion improver such as coupling agent, heat stabilizer, antibacterial / antifungal agent, flame retardant, gloss Erasing agent, defoaming agent, leveling agent, wetting / dispersing agent, anti-settling agent, thickening agent / sagging inhibitor, color-coding inhibitor, emulsifier, slip / scratch inhibitor, anti-skin agent, desiccant, antifouling agent It may contain components such as an agent, an antistatic agent, a conductive agent (electrostatic aid), and a solvent. These components may be used alone or in combination of two or more. These components can be appropriately selected from known ones and used. In addition, these blending amounts can be appropriately set.

When the resin composition is for an optical material, it may contain other components as appropriate depending on the use of the optical material. Specific examples of the above other components include ultraviolet absorbers, IR cut agents, reactive diluents, pigments, washing agents, antioxidants, light stabilizers, plasticizers, non-reactive compounds, defoamers and the like. Is preferably mentioned.

The resin composition preferably has a glass transition temperature (Tg) of 80 to 400 ° C. When the glass transition temperature is in the above range, the molding process can be easily performed. The glass transition temperature is more preferably 100 ° C. or higher, more preferably 115 ° C. or higher, and 300 ° C. or lower from the viewpoint of facilitating molding processing, from the viewpoint of increasing heat resistance. More preferably, it is more preferably 200 ° C. or lower.
The glass transition temperature can be obtained by the same method as the method for measuring the glass transition temperature of the polymer described above.

The resin composition preferably has a refractive index of 1.6 or more. When the refractive index is in the above range, it can be suitably applied as an optical material or the like. The refractive index is more preferably 1.65 or more, and further preferably 1.7 or more.
The refractive index can be obtained by the same method as the method for measuring the refractive index of the polymer described above.

The resin composition preferably has an Abbe number of 10 or more. When the Abbe number is in the above range, the light dispersion is small and the optical material can be suitable for a lens. The Abbe number is more preferably 15 or more, further preferably 20 or more, and even more preferably 30 or more. The Abbe number is more preferably 60 or less, and further preferably 50 or less, from the viewpoint of adjusting the light dispersibility.
The Abbe number can be obtained by the same method as the method for measuring the Abbe number of the polymer described above.

The resin composition preferably has a visible light transmittance of 75% or more. When the visible light transmittance is in the above range, it can be suitably used for an optical material. The visible light transmittance is more preferably 80% or more, more preferably 85% or more, and further preferably 88% or more.
The visible light transmittance can be obtained by the same method as the method for measuring the visible light transmittance of the polymer described above.

The resin composition preferably has a linear expansion coefficient of 70 ppm / ° C. or less. When the linear expansion coefficient of the resin composition is within the above range, the change in the refractive index due to temperature becomes small, and the resin composition can be suitably used for various applications such as optical materials, encapsulants, and coating materials. The coefficient of linear expansion is more preferably 50 ppm / ° C. or less, and further preferably 20 ppm / ° C. or less, in that changes in optical characteristics due to temperature changes can be suppressed. The lower limit of the linear expansion coefficient is not particularly limited, but is preferably 1 ppm / ° C. or higher, and more preferably 3 ppm / ° C. or higher.
The coefficient of linear expansion can be measured and obtained by a method according to JIS K 7197: 2012.

The method for producing the resin composition is not particularly limited, and examples thereof include a method of mixing the metal oxide particles, a binder resin, and, if necessary, other components. Examples of the mixing include known means such as a bead mill, a roll mill, a ball mill, a jet mill, a kneader, and a blender.

<Use>
Since the resin composition of the present invention has a high refractive index and excellent transparency, it can be suitably used for applications requiring high refractive index or high transparency.

The resin composition of the present invention is, for example, an image pickup lens, an optical material (member), a mechanical component material, an electric / electronic component material, an automobile component material, a civil engineering / building material, a molding material, etc., as well as a paint or adhesive material, etc. Used for various purposes. Among them, it is particularly preferably used for optical materials, optodevice members, display device members, and the like, and is more preferably used for optics. Specific examples of such applications include eyeglass lenses, image pickup lenses for cameras such as (digital) cameras, mobile phone cameras, and in-vehicle cameras, light beam condensing lenses, lenses such as light diffusion lenses, and LEDs. Encapsulants, optical adhesives, bonding materials for optical transmission, filters, diffraction grids, prisms, optical guides, watch glasses, transparent glass such as cover glass for display devices, and optical applications such as cover glass; photosensors, Optodevice applications such as photoswitches, LEDs, light emitting elements, optical waveguides, duplexers, demultiplexers, breakers, optical dividers, optical fiber adhesives; substrates for display elements such as LCDs, organic ELs, and PDPs, colors Examples thereof include display device applications such as filter substrates, touch panel substrates, display protective films, display backlights, light guide plates, antireflection films, and antifogging films.

The resin composition is preferably thermoplastic. If it is thermoplastic, the molding process is easy and the productivity is excellent.

The resin composition can also be suitably used as a molding material. The molding method is not particularly limited, and examples thereof include generally known methods for processing thermoplastic resins such as injection molding, extrusion molding, T-die method, and inflation method. Further, it may be formed into a desired shape by a method such as casting or coating. The shape is not particularly limited, and examples thereof include various known shapes such as a lens, a sheet, and a film.

As described above, the resin composition of the present invention has a high refractive index, is excellent in suppressing aggregation of metal oxide particles, and can be suitably used for various applications such as optics.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

In the examples, each evaluation was performed by the following method.
<Weight average molecular weight (Mw), number average molecular weight (Mn), dispersity (Mw / Mn)>
The weight average molecular weight and the number average molecular weight of the polymer were determined by measurement under the following conditions by gel permeation chromatography (GPC) method. The degree of dispersion was calculated by dividing the weight average molecular weight by the number average molecular weight.
Equipment: SHIMAZU, CBM-20A
Detector: Differential Refractometer Detector (RI) (SHIMAZU, SPD-20MA) and Ultraviolet-Visible Infrared Spectrophotometer (SHIMAZU, SPD-20MA)
Columns: TOSOH, TSKgel SuperHM-N
Column temperature: 40 ° C
Flow velocity: 0.3 mL / min
Calibration curve: Polystyrene Standards
Eluent: Chloroform

<Infrared spectroscopy (IR)>
IR measurement was performed under the following conditions.
Device: JASCO Fourier Transform Infrared Spectrophotometer (FT / IR-6100)
Sample Preparation: About 2 mg of sample was diluted with about 300 mg of dry potassium bromide (KBr). The mixture was ground in a mortar and pestle and molded.

<Thermogravimetric analysis (TGA, TG-DTA)>
The measurement was performed under the following conditions.
Equipment: Rigaku, TG8120
Conditions: Measurement temperature range 20-200 ° C (heating rate: 10.0 deg / min, holding for 30 minutes after reaching 200 ° C)
Between sampling: 1.0 sec
Atmosphere: N ₂ 50 mL / min

<X-ray diffraction measurement (XRD)>
The measurement was performed under the following conditions.
Equipment: Rigaku, RINT-UltimaIII
X-ray source: Cu Kα ray measurement range: 2θ = 10-60 °
Sampling interval: 0.04 °
Scanning speed: 10 ° / min

<Glass transition temperature (Tg)>
From the DSC curve obtained by heating from room temperature to 250 ° C at a heating rate of 10 ° C / min using a differential scanning calorimetry (DSC) manufactured by Seiko Electronics Co., Ltd. and using α-alumina as a reference. It was evaluated and calculated by the intersection of the baseline and the tangent at the inflection.

<Transmittance of blended film>
The measurement was performed with a spectrophotometer (Ultraviolet-visible-infrared spectrophotometer V-700 series manufactured by JASCO Corporation). Air was used as a control sample. In order to evaluate the visible light transmittance, it was evaluated at a transmittance of 400 nm.

<Refractive index (n _D )>
With respect to the obtained film, the phase difference of the polarization and the reflection declination ratio before and after the incident were measured using a spectroscopic ellipsometer UVISEL manufactured by HORIBA Scientific. For the wavelength (450 nm) and incident angle (75 °) of the incident light, the complex refractive index is obtained by using the preset values, the refractive index at 190-2000 nm is calculated, and the refractive index at the wavelength of 589.3 nm is obtained. rice field.
Unless otherwise stated, 30 mg of the polymer or resin composition was dissolved in 1,1,2,2-tetrachloroethane (1 ml), passed through a membrane filter having a pore size of 0.2 μm, and passed through the filter. 0.4 ml of the solution was taken and dropped cast onto a glass substrate (2 cm × 2 cm) to obtain a film having a film thickness of about 50 nm, which was measured.

<Element content ratio O / S ratio>
Using a sample formed by spin-coating 0.25 ml of a polymer solution on a silicon wafer, a JEOL photoelectron spectrometer (JPS-9010TR, XPS device, light source: Mg, X-ray output: 400 W) was used. The O / S ratio was calculated by measuring the peak intensity derived from the 2p orbital of the sulfur atom and the peak intensity derived from the 1s orbital of the oxygen atom and calculating the integral ratio thereof. If necessary, the peak intensity derived from the 1s orbital of the carbon atom was also measured, and the O / S ratio was calculated in consideration of the result.
For the measurement method and the position of the binding energy, the Handbook of X-ray Photoelectron Spectroscopy (JEOL Ltd., published in March 1991) was referred to.

Example 1
(Synthesis of poly (2,6-dimethyl disulfide) (PMPS))
In a nitrogen atmosphere, in a 50 ml three-necked flask, add 3,3', 5,5'-tetramethyldiphenyl disulfide (5 g, 18 mmol) and 2,3-dichloro-5,6-dicyano-parabenzoquinone (DDQ, 2M). And trifluoromethanesulphonic acid (1M) in a 1,1,2,2-tetrachloroethane solution (10 ml) and stirred at room temperature for 40 hours for oxidative polymerization. After 40 hours, the 1,1,2,2-tetrachloroethane solution was added dropwise to hydrochloric acid acidic methanol, and the powder was recovered with a glass filter. Then, it was washed with an aqueous potassium hydroxide solution (0.1 M) and pure water, and vacuum dried to obtain a polymer (PMPS). The glass transition temperature of the polymer was 162 ° C. The O / S ratio was 0.02. The refractive index was 1.69.

(Bromo modification on the surface of titanium oxide fine particles)
4 mL of 3-glycidyloxypropyltrimethoxysilane SCA-ep (1.00 g, 4.23 mmol) and 2-bromo-2-methylpropionic acid (0.84 g, 5.00 mmol) in a 30 mL flask. Was dissolved in tetrahydrofuran (THF) and reacted at 70 ° C. for 20 hours. A bromo-containing silane coupling agent (SCA-Br) was obtained as a yellow viscous liquid through liquid separation with water / chloroform and drying under reduced pressure.
Subsequently, anatase-type TiO ₂ fine particles (manufactured by Aldrich, particle size <25 nm, 1.0 g) were dispersed in toluene (60 mL), and the obtained SCA-Br (0.40 g) and triethanolamine (TEA) ( 0.1 mL) was added, and the mixture was reacted at 50 ° C. for 24 hours under an N ₂ atmosphere. After washing with toluene and chloroform in a dialysis membrane and drying under reduced pressure, titanium oxide fine particles TiO ₂ -Br having a bromo group on the surface were obtained as a white powder.
From IR, a peak derived from CH expansion and contraction near 2900 cm ^-1 and C = O expansion and contraction near 1700 cm ^-1 and O-Si—O expansion and contraction near 1100 cm ^-1 was observed, supporting the progress of the reaction. Further, the modified portion was calculated from TGA as 11 wt% (0.19 mmol Br initiator per 1 g of TiO ₂ -Br).

(Polystyrene modification on the surface of titanium oxide fine particles by ATRP (Atom Transfer Radical Polymerization))
As an initiator, TiO ₂ -Br (0.10 g, Br: 1eq) obtained above and ethyl 2-bromoisobutyrate EBiB (3eq) were stirred in anisole, and styrene (460eq) and CuBr / PMDETA were used as monomers. The catalyst (3eq) was added, degassed, and reacted at 90 ° C. for 24 hours. After the reaction, the reaction solution was dissolved and dispersed in chloroform, the supernatant was recovered by centrifugation, and free polystyrene was removed by precipitation purification with methanol. The precipitate obtained by centrifugation was dispersed again in chloroform, purified by precipitation in methanol, and subjected to centrifugation to obtain polystyrene-modified titanium oxide fine particles TiO ₂ -PS as a white powder. The fine particle TiO ₂ -PS was evaluated by TG-DTA, and the weight ratio of TiO _2- / PS was 78 wt% / 22 wt% and the Tg was 90 ° C. based on the decomposition weight of polystyrene (PS). From the evaluation of the molecular weight of PS, Mn = 6100 and Mw / Mn = 1.1.
From IR, aliphatic and aromatic ring CH expansion and contraction were observed around 2900 to 3050 cm ^-1 , and aromatic ring expansion and contraction was observed around 1500 cm ^-1 . In addition, from XRD, a crystalline peak derived from anatase-type TiO ₂ and an amorphous broad derived from polystyrene were observed in the vicinity of 2θ = 15 ° to 30 °. From the above, we supported the progress of the reaction.

(Evaluation of compatibility of TiO ₂ -PS / PMPS blend film and optical characteristics)
A resin composition was prepared by dissolving and dispersing TiO ₂ -PS (Tg: 94 ° C.) and PMPS (Tg: 162 ° C.) prepared above in toluene at a weight ratio of 1/1 at 20 mg / mL. ..
The obtained resin composition was formed into a film on a glass substrate by a drop casting method. The blend film obtained by drop casting was visually transparent. In addition, DSC showed a single glass transition point (Tg: 120 ° C.). From this, good compatibility (homogeneity) between TiO ₂ -PS and PMPS was confirmed.
In addition, the transmittance of the obtained blended membrane was measured. It showed a high transmittance of 80% or more in the visible light region (400 to 700 nm) and 84.8% at 400 nm.
FIG. 1 shows measurement data of the transmittance of the blend film obtained in Example 1. FIG. 2 shows a photograph of the blend film obtained in Example 1.
The refractive index of the obtained blend film was 1.68.
From the above, it was confirmed that the resin composition of the example has a high refractive index, is excellent in suppressing aggregation of metal oxide particles, and provides a blend film having a high transmittance.

Claims (6)

A resin composition containing metal oxide particles coated with a polymer material and a binder resin.
The polymer material and / or the binder resin has a structural unit (A) represented by the following general formula (1), a structural unit (B) represented by the following general formula (2), and the following general formula. A resin composition comprising a polymer having at least one structural unit selected from the group consisting of the structural unit (C) represented by (3).

(In formulas (1) to (3), X ¹ , X ² and X ³ represent divalent aromatic hydrocarbon groups that may have the same or different substituents.) The structural unit (A) is a structural unit (A-1) represented by the following general formula (1-1).
The structural unit (B) is a structural unit (B-1) represented by the following general formula (2-1).
The resin composition according to claim 1, wherein the structural unit (C) is a structural unit (C-1) represented by the following general formula (3-1).

(In formulas (1-1), (2-1) and (3-1), R ¹ , R ² and R ³ may have the same or different halogen atoms, hydroxyl groups, or substituents. It represents a good alkyl group, alkoxy group, aryl group, aralkyl group, or sulfur-containing substituent. A represents the number of R ¹ and is an integer of 0 to 4. b represents the number of R ² . It is an integer of 0 to 4. ^c represents a number of R3 and is an integer of 0 to 4.) The polymer is characterized in that the element content ratio (O / S) of the oxygen atom O bonded to the sulfur atom S of the main chain and the sulfur atom S of the main chain is 0.1 to 1.5. The resin composition according to claim 1 or 2. The resin composition according to any one of claims 1 to 3, wherein the composition further contains a compound having a (poly) styrene skeleton. The resin composition according to any one of claims 1 to 4, wherein the compound having a (poly) styrene skeleton and the metal oxide particles are covalently bonded. The resin composition according to any one of claims 1 to 5, which is for optical use.

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