JP2007161980A - Masterbatch, optical element, method for producing masterbatch, and method for manufacturing optical element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To further uniformize composition and enhance transparency compared to conventional art in case of mixing an inorganic fine particle in a resin. <P>SOLUTION: The masterbatch for use in manufacture of an objective lens 15 is obtained by a wet mixing of a cyclic olefin resin with inorganic fine particles having ≤30 nm volume-average dispersion particle diameter as principal components, where the content of the inorganic fine particle is 20-300 pts.vol. relative to 100 pts.vol. of the cyclic olefin resin. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a master batch used for manufacturing an optical element, an optical element using the master batch, a method for manufacturing a master batch, and a method for manufacturing an optical element.

  2. Description of the Related Art Conventionally, information devices such as players, recorders, and drives that read and record information using optical information recording media such as MO, CD, and DVD are provided with an optical pickup device. The optical pickup device includes an optical element unit including an optical element such as a lens for irradiating a medium with light having a predetermined wavelength emitted from a light source or causing a light receiving element to receive reflected light. .

  As a material for such an optical element, a plastic such as a copolymer of a cyclic olefin and an α-olefin is used because it can be manufactured at low cost by means such as injection molding (for example, Patent Document 1). reference).

  Here, optical stability similar to that of glass materials is required for plastic materials used for optical elements. Therefore, for example, a plastic material such as a cyclic olefin has an extremely low water absorption rate as compared with PMMA, which is a plastic material that has been conventionally used, and the refractive index change due to water absorption is greatly improved. However, the temperature dependence of the optical properties has not been solved yet, and it is currently one order of magnitude larger than that of inorganic glass.

In recent years, physical properties such as rigidity and heat resistance have been improved by mixing fillers such as inorganic fine particles with a resin in order to improve the disadvantages of such plastic materials (for example, Patent Documents 1 to 3). reference). In order to use a filler-filled resin composition as an optical material, from the viewpoint of maintaining the transparency of the resin, it is necessary to make the filler diameter sufficiently small or match the refractive index of the filler to the refractive index of the resin, In the latter case, there are many restrictions to make the refractive indexes of the filler and the resin exactly coincide with each other, which is not suitable for practical use. Therefore, the former application is being studied.
JP-A-8-92424 JP 2004-59875 A Japanese Patent Application No. 5-218617

However, in the manufacturing method disclosed in Patent Document 1, since a master batch is prepared by mixing SiO ₂ particles having a large particle size of 1 to ₄ μm with a resin, the transmittance of the plastic material is deteriorated, and the optical application Not suitable for.

  Further, in the manufacturing method disclosed in Patent Document 2, since a master batch is prepared by melt-kneading inorganic fine particle powder and a resin, when the inorganic fine particles have high fluidity, the inorganic fine particles are scattered. Cheap. Therefore, the inorganic fine particles cannot be stably supplied into the resin, and the composition of the master batch and the composite material using the master batch becomes non-uniform.

  Moreover, in the manufacturing method disclosed in Patent Document 3, since the inorganic fine particles are mixed with the thermosetting resin, the inorganic fine particles once mixed in the resin cannot be dispersed again in the resin. Therefore, the composition of the composite material may not be made uniform.

  An object of the present invention is to provide a masterbatch, an optical element, a masterbatch manufacturing method, and an optical element that can make the composition uniform and improve transparency as compared with the conventional case when mixing inorganic fine particles in a resin. It is to provide a manufacturing method.

The invention according to claim 1 is a master batch.
A cyclic olefin resin;
Inorganic fine particles having a volume average dispersed particle size of 30 nm or less are mixed as a main component in a wet manner,
Content of the said inorganic fine particle is 20 volume part or more and 300 volume part or less with respect to 100 volume part of said cyclic olefin resins, It is characterized by the above-mentioned.

The invention according to claim 2 is the masterbatch according to claim 1,
The inorganic fine particles contain at least silicon oxide.

The invention according to claim 3 is the master batch according to claim 1 or 2,
The inorganic fine particles include metal oxide fine particles containing at least two or more different metal atoms.

Invention of Claim 4 is an optical element,
It formed by shape | molding the composite material of the masterbatch as described in any one of Claims 1-3, and a thermoplastic resin, It is characterized by the above-mentioned.

Invention of Claim 5 is a manufacturing method of a masterbatch,
A cyclic olefin resin;
Comprising a mixing step of wet mixing with inorganic fine particles having a volume average dispersed particle size of 30 nm or less as a main component;
In this mixing process,
Content of the said inorganic fine particle shall be 20 to 300 volume parts with respect to 100 volume parts of said cyclic olefin resins.

Invention of Claim 6 is the manufacturing method of the masterbatch of Claim 5,
As the inorganic fine particles, those containing at least silicon oxide are used.

Invention of Claim 7 is a manufacturing method of the masterbatch of Claim 5 or 6,
As the inorganic fine particles, those containing metal oxide fine particles containing at least two or more different metal atoms are used.

The invention according to claim 8 is a method of manufacturing an optical element,
It includes a molding step for forming an optical element by molding a composite material of a master batch produced by the method for producing a master batch according to any one of claims 5 to 7 and a thermoplastic resin. To do.

  According to the invention as described in any one of Claims 1-8, when mixing inorganic fine particles in resin, compared with the former, it can make a composition uniform and can improve transparency.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, in the following embodiments, various technically preferable limitations for carrying out the present invention are given, but the scope of the invention is not limited to the following embodiments and illustrated examples.

First, the master batch according to the present invention will be described.
The masterbatch in the present embodiment constitutes a composite material for an optical element described later by being diluted with a thermoplastic resin, and contains a cyclic olefin resin and inorganic fine particles. Hereinafter, (1) cyclic olefin resin, (2) inorganic fine particles, (3) masterbatch production method, (4) thermoplastic resin, (5) composite material production method using masterbatch, (6) molded body (7) An application example of a molded body as an optical element will be described.

(1) Cyclic Olefin Resin The cyclic olefin resin in the present invention is not particularly limited as long as it is generally used as an optical material. For example, a norbornene polymer, a monocyclic olefin polymer, a cyclic Conjugated diene polymers, hydrogenated products thereof, and the like are specifically mentioned. Specifically, “ZEONEX” (product name, manufactured by Nippon Zeon Co., Ltd.), “Arton” (product name, manufactured by JSR Corporation), “Appel” (product) Name, manufactured by Mitsui Chemicals), “TOPAS” (product name, manufactured by Polyplastics), and the like.

(2) Inorganic fine particles The inorganic fine particles in the present invention have a primary particle size volume average dispersed particle size of 30 nm or less, more preferably 1 nm or more and 30 nm or less, and further preferably 1 nm or more and 10 nm or less. If the volume average dispersed particle size is 1 nm or more, the dispersibility of the inorganic fine particles can be ensured and desired performance can be obtained, and if the volume average dispersed particle size is 30 nm or less, the resulting thermoplasticity Good transparency of the material composition can be obtained, and a light transmittance of 70% or more can be achieved.

  Here, the volume average dispersed particle diameter refers to a diameter when inorganic fine particles in a dispersed state are converted into spheres having the same volume. Moreover, even if the particle size of the aggregated primary particles is 30 nm or more, it is possible to ensure desired transparency by deaggregating and dispersing the aggregate, but the primary particles themselves are 30 nm or more. Since it is difficult to obtain particles having a particle size of 30 nm or less by pulverizing the primary particles, the size of the primary particles is important.

  The shape of the inorganic fine particles that can be used in the present invention is not particularly limited, but spherical fine particles are preferably used. Further, the particle size distribution is not particularly limited, but in order to achieve the effect of the present invention more efficiently, a material having a relatively narrow distribution is preferable to a material having a wide distribution. Used.

  Examples of the inorganic fine particles include oxide fine particles, and more specifically, for example, silica, titanium oxide, zinc oxide, aluminum oxide, zirconium oxide, hafnium oxide, niobium oxide, tantalum oxide, magnesium oxide, calcium oxide. Strontium oxide, barium oxide, yttrium oxide, lanthanum oxide, cerium oxide, indium oxide, tin oxide, lead oxide, lithium niobate, potassium niobate, lithium tantalate, etc., which are double oxides composed of these oxides, Or a phosphate, a sulfate, etc. can be mentioned.

Further, fine particles having a semiconductor crystal composition can be preferably used as the inorganic fine particles. Although there is no restriction | limiting in particular in such a semiconductor crystal composition, What does not produce absorption, light emission, fluorescence, etc. in the wavelength range used as an optical element is desirable. Specific examples of the composition include, for example, a simple substance of Group 14 element of the periodic table such as carbon, silicon, germanium and tin, a simple substance of Group 15 element of the periodic table such as phosphorus (black phosphorus), and a periodicity of selenium, tellurium and the like. Table 16 group element simple substance, compound consisting of plural periodic table group 14 elements such as silicon carbide (SiC), tin oxide (IV) (SnO ₂ ), tin sulfide (II, IV) (Sn (II) Sn (IV) S ₃ ), tin sulfide (IV) (SnS ₂ ), tin sulfide (II) (SnS), tin selenide (II) (SnSe), tin telluride (II) (SnTe), lead sulfide (II) ) (PbS), lead selenide (II) (PbSe), lead telluride (II) (PbTe) periodic table group 14 element and periodic table group 16 element compound, boron nitride (BN), phosphorus Boron phosphide (BP), boron arsenide (BAs), aluminum nitride (AlN), aluminum phosphide ( lP), aluminum arsenide (AlAs), aluminum antimonide (AlSb), gallium nitride (GaN), gallium phosphide (GaP), gallium arsenide (GaAs), gallium antimonide (GaSb), indium nitride (InN), phosphide Compounds of Group 13 elements of the periodic table and Group 15 elements of the periodic table such as indium (InP), indium arsenide (InAs), indium antimonide (InSb), etc. (or III-V group compound semiconductors), aluminum sulfide (Al ₂ S _3), aluminum selenide (Al ₂ Se _3), gallium sulfide (Ga ₂ S _3), gallium selenide (Ga ₂ Se _3), telluride gallium (Ga ₂ Te _3), indium oxide (In ₂ O ₃ ), indium sulfide (In ₂ S _3), indium selenide (In ₂ Se _3), telluride indicator Arm (In ₂ Te ₃₎ Periodic Table compounds of a Group 13 element and Periodic Table Group 16 element such as, thallium chloride (I) (TlCl), thallium bromide (I) (TlBr), thallium iodide (I ) (TlI) and other compounds of group 13 elements of the periodic table and group 17 elements of the periodic table, zinc oxide (ZnO), zinc sulfide (ZnS), zinc selenide (ZnSe), zinc telluride (ZnTe), oxidation Periodic table 12 of cadmium (CdO), cadmium sulfide (CdS), cadmium selenide (CdSe), cadmium telluride (CdTe), mercury sulfide (HgS), mercury selenide (HgSe), mercury telluride (HgTe), etc. Compounds of group elements and group 16 elements of the periodic table (or II to VI compound semiconductors), arsenic sulfide (III) (As ₂ S ₃ ), arsenic selenide (III) (As ₂ Se ₃ ), arsenic telluride (III (As ₂ Te _3), antimony sulfide _{(III) (Sb 2 S 3} ), selenium antimony _{(III) (Sb 2 Se 3} ), antimony telluride _{(III) (Sb 2 Te 3} ), bismuth sulfide (III) Compound of periodic table group 15 element and periodic table group 16 element such as (Bi ₂ S ₃ ), bismuth selenide (III) (Bi ₂ Se ₃ ), bismuth telluride (III) (Bi ₂ Te ₃ ) , Compounds of Group 11 elements of the periodic table and Group 16 elements of the periodic table, such as copper (I) (Cu ₂ O), copper selenide (Cu ₂ Se), copper chloride (I) (CuCl) , Copper (I) bromide (CuBr), copper iodide (I) (CuI), silver chloride (AgCl), silver bromide (AgBr) periodic table group 11 elements and periodic table group 17 elements A compound of a periodic table group 10 element and a periodic table group 16 element such as a compound, nickel oxide (II) (NiO), etc. Cobalt (II) (CoO), compounds of cobalt sulfide (II) (CoS) periodic table Group 9 element and Periodic Table Group 16 element such as, triiron tetraoxide (Fe ₃ O _4), iron sulfide ( II) Compound of periodic table group 8 element such as (FeS) and periodic table group 16 element, compound of periodic table group 7 element such as manganese (II) (MnO) and periodic table group 16 element , Compounds of periodic table group 6 elements and periodic table group 16 elements such as molybdenum sulfide (IV) (MoS ₂ ) and tungsten oxide (IV) (WO ₂ ), vanadium oxide (II) (VO), vanadium oxide (IV) Compound of periodic table group 5 element and periodic table group 16 element such as (VO ₂ ), tantalum oxide (V) (Ta ₂ O ₅ ), titanium oxide (TiO ₂ , Ti ₂ O ₅ , Ti ₂ O _3, Ti ₅ O _9, etc.) compounds of the periodic table group 4 element and periodic table group 16 element such as, sulfide Ma Neshiumu (MgS), compounds of Group 2 elements and Periodic Table Group 16 element such as magnesium selenide (MgSe), cadmium (II) oxide Chromium _{(III) (CdCr 2 O 4} ), cadmium selenide ( II) Chalcogen spinels such as chromium (III) (CdCr ₂ Se ₄ ), copper sulfide (II) chromium (III) (CuCr ₂ S ₄ ), mercury selenide (II) chromium (III) (HgCr ₂ Se ₄ ) And barium titanate (BaTiO ₃ ). In addition, G. Schmid et al .; Adv. Mater. 4, 494 (1991) (BN) ₇₅ (BF ₂ ) ₁₅ F ₁₅ and D. Fenske et al .; Angew. Chem. Int. Ed. Engl. 29, page 1452 (1990), a semiconductor cluster having a fixed structure such as Cu ₁₄₆ Se ₇₃ (triethylphosphine) ₂₂ reported in the same manner is also exemplified.

  As these inorganic fine particles, one type of inorganic fine particles may be used, or a plurality of types of inorganic fine particles may be used in combination. It is also possible to use inorganic fine particles having a composite composition. As the plural types of inorganic fine particles, any of mixed type, core-shell (laminated) type, compound type, and composite type (a type in which one other inorganic fine particle exists in one base material inorganic fine particle) can be used. .

  Examples of the inorganic fine particles having a composite composition include Li, Na, Mg, Al, Si, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Rb, Sr, Y, Two or more metals selected from the group consisting of Nb, Zr, Mo, Ag, Cd, In, Sn, Sb, Cs, Ba, La, Ta, Hf, W, Ir, Tl, Pb, Bi and rare earth metals A metal oxide or the like can be used. Specifically, for example, silicon oxide, titanium oxide, zinc oxide, aluminum oxide, zirconium oxide, hafnium oxide, niobium oxide, tantalum oxide, magnesium oxide, calcium oxide, strontium oxide, barium oxide, indium oxide, tin oxide, oxide Examples thereof include oxide fine particles having a configuration in which two or more oxides such as lead are mixed. Among these, those that do not generate absorption, light emission, fluorescence, or the like in the wavelength region used as an optical element are preferably selected and used.

  In the case of selecting inorganic fine particles from the viewpoint of improving the physical properties such as heat resistance in addition to the improvement of transparency, which is the object of the present invention, silicon oxide and aluminum oxide, zirconium oxide, titanium oxide, zinc oxide, niobium oxide, magnesium oxide, etc. These composite oxides are preferably used from the viewpoints of refractive index, various temperature characteristics, and production costs. In the composition distribution of the composite particles, the outer surface portion (shell portion) and the central portion (core portion) may be different compositions or the same composition, and physical properties such as compatibility with the resin (core / shell) It is appropriately selected in consideration of optical characteristics such as interface scattering and (shell / resin) interface scattering. Here, the outer surface portion is, for example, 90 to 100% of the particle diameter from the particle center, and the center portion is, for example, 0 to 50% of the particle diameter from the particle center, but is not limited thereto. As a method for measuring the composition distribution, there are a method calculated from elemental analysis by EDX, a method based on ASTM D542, a Becke line method, a dispersion method, and the like. In the present invention, values directly calculated by EDX were used.

The content of the inorganic fine particles in the master batch is 25 parts by volume or more and 300 parts by volume or less with respect to 100 parts by volume of the above-mentioned cyclic olefin resin.
Moreover, the volume ratio of the inorganic fine particles in the resin composition when the master batch is diluted with the above-described thermoplastic resin is 1 to 70 vol%, preferably 10 to 50 vol%. When the inorganic fine particle content is 1 vol% or less, desired physical property improvement may not be obtained. In addition, when the inorganic fine particle content of the inorganic fine particle-containing thermoplastic resin composition for optical elements is 70 vol% or more, there is a problem in economic efficiency and moldability.

(2.1) Method for Producing Inorganic Fine Particles The method for producing inorganic particles in the present invention is not particularly limited, and any known method can be used. Spray drying method, flame spray method, plasma method, gas phase reaction method, freeze drying method, thermal kerosene method, thermal petroleum method such as heated petroleum method, coprecipitation method, salt solution method, alkoxide method, hydrolysis method such as sol-gel method, Examples thereof include a hydrothermal method such as a precipitation method, a crystallization method, a hydrothermal decomposition method, and a hydrothermal oxidation method. Among these, the thermal decomposition method, the precipitation method, and the hydrolysis method are preferable from the viewpoint of producing inorganic fine particles having a volume dispersion particle size of 30 nm or less. It is also preferable to combine a plurality of these methods.

  For example, desired oxide fine particles can be obtained by using a single or a plurality of metal halides or alkoxy metals as raw materials and hydrolyzing in a reaction system containing water. At this time, a method of using an organic acid, an organic amine or the like in combination is also used for stabilizing the fine particles. More specifically, for example, in the case of forming titanium dioxide fine particles, the method described in Journal of Chemical Engineering of Japan Vol. 31, No. 1, pp. 21-28 (1998) may be used. In the case of forming zinc sulfide, a known method described in Journal of Physical Chemistry, Vol. 100, pages 468-471 (1996) can be used. According to these methods, for example, titanium oxide having a volume average dispersed particle size of 5 nm is added with a suitable surface modifier when hydrolyzed in a suitable solvent using titanium tetraisopropoxide or titanium tetrachloride as a raw material. By doing so, it can be manufactured easily. Zinc sulfide having a volume average dispersed particle size of 40 nm can be produced by using dimethyl zinc or zinc chloride as a raw material and adding a surface modifier when sulfurating with hydrogen sulfide or sodium sulfide.

  Also, as a commonly used method for producing fine oxide particles, a chemical flame is formed by a burner in an atmosphere containing oxygen, and an amount of metal powder capable of forming a dust cloud is charged into the chemical flame and burned. A desired oxide in the gas phase by a method of synthesizing oxide fine particles having a volume average dispersed particle size of 5 to 30 nm by the reaction of a raw material gas stream and oxygen gas as described in JP-A-2005-218937 A method of obtaining fine particles can also be used.

(2.1.1) Types of surface modifiers The inorganic fine particles can improve the affinity with various resin materials by surface modification. The method of surface modification is not particularly limited, and any known method can be used. For example, there is a method of modifying the surface of the fine particles by hydrolysis under conditions where water is present. In this method, a catalyst such as an acid or an alkali is preferably used, and it is generally considered that a hydroxyl group on the surface of fine particles and a hydroxyl group generated by hydrolysis of a surface modifier dehydrate to form a bond.

Examples of the method for modifying the surface of the inorganic fine particles include surface treatment with a surface modifier such as a coupling agent, polymer graft, and surface treatment with mechanochemical.
Examples of the surface modifier used for the surface modification of inorganic fine particles include silane coupling agents, amino acid dispersants, various silicone oils, titanate, aluminate and zirconate coupling agents. These are not particularly limited, and can be appropriately selected depending on the type of inorganic fine particles and the thermoplastic resin in which the inorganic fine particles are dispersed. Further, two or more surface treatments with various surface treatment agents may be performed simultaneously or at different times.

  Here, specific examples of the silane coupling agent include vinylsilazane trimethylchlorosilane, dimethyldichlorosilane, methyltrichlorosilane, trimethylalkoxysilane, dimethyldialkoxysilane, methyltrialkoxysilane, hexamethyldisilazane, and the like. Although one can be used, hexamethyldisilazane or the like is preferably used in order to widely cover the surface of the inorganic fine particles.

Specific examples of the silicone oil-based treatment agent include straight silicone oils such as dimethyl silicone oil, methylphenyl silicone oil, and methylhydrogen silicone oil, amino-modified silicone oil, epoxy-modified silicone oil, carboxyl-modified silicone oil, Nord-modified silicone oil, methacryl-modified silicone oil, mercapto-modified silicone oil, phenol-modified silicone oil, one-end reactive modified silicone oil, different functional group-modified silicone oil, polyether-modified silicone oil, methylstyryl-modified silicone oil, alkyl-modified silicone Oil, higher fatty acid ester modified silicone oil, hydrophilic special modified silicone oil, higher alkoxy modified silicone N'oiru, can be used higher fatty acid containing modified silicone oil, modified silicone oil and fluorine modified silicone oil.
These surface treatment agents may be appropriately diluted with hexane, toluene, methanol, ethanol, acetone water or the like.

(2.1.2) Surface modification method of inorganic fine particles The method of surface modification of inorganic fine particles is not particularly limited, and any known method can be used. For example, there is a method of modifying the surface of the fine particles by hydrolysis under conditions where water is present. In this method, a catalyst such as an acid or an alkali is preferably used, and it is generally considered that a hydroxyl group on the surface of fine particles and a hydroxyl group generated by hydrolysis of a surface modifier dehydrate to form a bond.

(2.1.3) Surface modification method using a coupling agent In addition to the above surface modification methods, surface modification methods using a coupling agent include a wet heating method, a wet filtration method and an integral blend method. The invention is not particularly limited. Before the production of the master batch according to the present invention, the inorganic fine particles may be surface-treated in advance by these methods.

  Here, the amount of the coupling agent added is relatively large because the inorganic fine particles used are nano-sized and have a large specific surface area. As a specific amount, 5 parts by weight or more is necessary with respect to 100 parts by weight of the inorganic fine particles. Thereby, the expected surface treatment effect can be obtained, and aggregation of particles can be prevented. Moreover, since it can prevent that a void generate | occur | produces in a thermoplastic material, the increase in the linear expansion coefficient resulting from a void and the fall of a light transmittance can be prevented. In addition, from the viewpoint of the increase in cost and the solubilization amount with the resin to be used, it is desirable that the amount of the coupling agent added is suppressed to 20 parts by weight or less with respect to 100 parts by weight of the inorganic fine particles.

(3) Masterbatch Manufacturing Method In the masterbatch manufacturing method according to the present invention, the above-mentioned cyclic olefin resin and inorganic fine particles having a volume average dispersed particle size of 30 nm or less are wet-mixed using a solvent (mixing) Step), the solvent is removed by drying. In this way, by mixing inorganic fine particles having a volume average dispersed particle size of 30 nm or less, a master batch, a composite material using the master batch, an optical element using the composite material, compared to a conventional case larger than 30 nm Can improve transparency. Moreover, the composition of the mixture can be made uniform by wet-mixing the cyclic olefin resin and the inorganic fine particles having a volume average dispersed particle size of 30 nm or less using a solvent.

  Here, the wet mixing means that an interface between the solid and the solvent is newly generated by contact of the solvent with the surface of the inorganic fine particles to be mixed and the solid surface becoming wet and disappearing (hereinafter referred to as condition (i)). And the mixture of the inorganic fine particles and the cyclic olefin resin in a state where the cyclic olefin resin that covers the entire interface is dissolved in the solvent (hereinafter referred to as condition (ii)). . In addition, the minimum amount of the solvent required for actual wet mixing is the larger amount of the necessary amounts for satisfying the above conditions (i) and (ii). However, the amount of the solvent specifically used is appropriately selected depending on the types of the inorganic fine particles and the cyclic olefin resin.

(3.1) Wet mixing device In wet mixing of cyclic olefin resin and inorganic fine particles, known devices such as a tumbler mixer, super mixer, Henschel mixer, screw blender, ribbon blender can be applied. A super mixer or the like that is less affected by materials is preferably used.

Here, the blending amount of the inorganic fine particles with respect to 100 parts by volume of the cyclic olefin resin is preferably 25 parts by volume or more and 100 parts by volume or less. If it is smaller than 25 parts by volume, the effect of the added inorganic fine particles is not sufficiently exhibited. On the other hand, when the volume is larger than 300 parts by volume, the resin as the binder is insufficient and a uniform composition cannot be obtained, and the adhesion between the interface between the inorganic fine particles and the cyclic olefin resin is insufficient and voids are generated. If the composite material is produced using a masterbatch containing voids in this way, resin deterioration occurs due to oxygen contained in the voids, or moisture contained in the air in the voids becomes bubbles as a resin composition. Since the light transmittance is reduced due to the presence in the optical element, the optical element becomes a defective product.
(3.2) Solvent

  As a solvent used for wet mixing, a solvent that dissolves the above composition is good, and from the viewpoint of adverse effects on the final composite material and economical efficiency, the residue after volatilization is 2% or less of the total volume. Those are preferred. Thereby, even if a solvent is dried and removed at the time of masterbatch creation, the influence on the final product by a residual solvent can be suppressed.

  Examples of such solvents include aromatic hydrocarbons such as benzene, toluene and xylene, ketones such as acetone, methyl ethyl ketone, cyclohexanone and heptanone, ethyl acetate, acetic acid-t-butyl, acetic acid-n-butyl, acetic acid. Esters such as -n-hexyl, halogenated hydrocarbons such as 1,2-dichloroethane, chloroform, chlorobenzene, 1,2-dimethoxyethane, diethylene glycol dimethyl ether, diethylene glycol ethyl methyl ether, diethylene glycol diethyl ether, tetrahydrofuran, 1,3 -Ethers such as dioxane and 1,4-dioxane, non-protons such as N, N-dimethylformamide, N, N-dimethylacetamide, dimethyl sulfoxide, N-methyl-2-pyrrolidone and sulfolane It can be mentioned polar solvents. Moreover, these solvents can be used individually or in mixture of 2 or more types.

  In addition, the boiling point of the solvent under atmospheric pressure conditions is preferably 30 to 200 ° C, more preferably 50 to 150 ° C. When the boiling point is lower than 30 ° C., handling is dangerous. On the other hand, if the boiling point is higher than 200 ° C., it is difficult to remove the solvent, and decomposition products remain, or the final product is adversely affected by heating.

  The amount of the solvent is not particularly limited as long as it satisfies both the above conditions (i) and (ii), but 500 to 2000 parts by weight of the solvent is preferable with respect to 100 parts by weight of the cyclic olefin resin. If the solvent is less than 500 parts by weight, the resin may not be completely dissolved and the master batch composition may be non-uniform. On the other hand, when the amount is more than 2000 parts by weight, productivity is lowered and sufficient torque cannot be obtained at the time of wet mixing, so that the composition of the prepared master batch may be non-uniform.

  Further, as the solvent, a non-condensable high-density fluid supercritical fluid exceeding the critical temperature (TC) and the critical pressure (PC) can also be used. In this case, in addition to being superior to other solvents in terms of separation and recovery, drying without causing capillary force is possible, so that aggregation of fine particles at the time of preparing a master batch can be suppressed.

(4) Thermoplastic resin As a thermoplastic resin for diluting the masterbatch according to the present invention, acrylic resin, cyclic olefin resin, polycarbonate resin, polyester resin, polyether resin, Although a polyamide resin, a polyimide resin, etc. can be considered, a cyclic olefin resin is preferable from a compatible viewpoint with a masterbatch. Further, as the thermoplastic resin, it is also preferable to use other resins compatible with these resins. Here, the term “compatible” refers to a property that can take one state of a complete compatibility that is soluble in a molecular state at an arbitrary ratio and a partial compatibility that is compatible under an arbitrary composition and temperature.

  In addition, this thermoplastic resin and the cyclic olefin resin described in the above (1) may include an acid-modified one from the viewpoint of particle dispersibility. Examples of such a resin include a polar group. Those prepared by a known technique such as a method of copolymerizing an unsaturated monomer with an olefin resin are preferably used.

  These resins preferably have a water absorption of 0.2% by mass or less from the viewpoint of dimensional stability. Here, when compatibilizing two or more components of the resin, the resin after compatibilization has the average of each component or the best properties of both of the physical and chemical properties. Therefore, for example, when two or more kinds of resins are used, the water absorption rate of the mixed resin is considered to be substantially equal to the average value of the water absorption rate of each resin, so that the average water absorption rate is 0.2% by mass or less. Good.

(5) Manufacturing method of composite material using masterbatch As a manufacturing method of composite material using masterbatch, from the viewpoint of highly dispersing inorganic fine particles, a masterbatch and a thermoplastic resin as a host material are mixed. However, a method of producing by applying a shearing force with a melt kneader is preferably used.

  Specific kneaders include KRC kneader (manufactured by Kurimoto Iron Works); polylab system (manufactured by HAAKE); nanoplast mill (manufactured by Toyo Seiki Seisakusho); Nauter mixer bus co-kneader (manufactured by Buss) ); TEM type extruder (manufactured by Toshiba Machine Co., Ltd.); TEX twin-screw kneader (manufactured by Nippon Steel Works); PCM kneader (manufactured by Ikegai Iron Works Co., Ltd.); ); Needex (manufactured by Mitsui Mining); MS pressure kneader, nider ruder (manufactured by Moriyama Seisakusho); Banbury mixer (manufactured by Kobe Steel).

  In addition, the ratio of the masterbatch contained in the composite material finally produced is about 5-50 w% normally. When the proportion of the master batch contained in the composite material is significantly small, the effect of improving the physical properties due to the inclusion of inorganic fine particles cannot be expected. On the other hand, when the ratio is significantly large, it takes time for uniform mixing in the kneading apparatus to cause deterioration of the resin, and adhesion of the master batch to the inner wall surface of the kneading apparatus becomes a problem.

Further, the mixing of the masterbatch and the thermoplastic resin is preferably carried out in an atmosphere of Ar, N ₂ or the like, not in the air, in order to prevent functional deterioration due to oxidation.

(5.1) Degree of mixing When the degree of mixing of the masterbatch and the thermoplastic resin is insufficient, the optical properties such as refractive index, Abbe number and light transmittance, thermoplasticity, melt moldability, etc. Sufficient mixing is desirable because it may affect the resin processability. It is important to select the degree of mixing in consideration of the characteristics of the thermoplastic resin and inorganic fine particles used.

(5.2) Resin additive For the masterbatch according to the present invention and the composite material containing the masterbatch, generally used antioxidants, neutralizers, lubricants, antistatic agents, whitening agents, heat Resin additives such as stabilizers, light stabilizers, plasticizers, colorants, impact modifiers, extenders, mold release agents, foaming agents, processing aids and the like can be blended as necessary. These various additives are commonly used and are known to those skilled in the art. Specific examples of such additives are described in R.A. Gachter and H.C. Muller, Plastics Additives Handbook, 4th edition, 1993.

  As such a resin additive, as long as it can be compatibilized with each material used, various additives can be appropriately used within a range not impairing the object of the present invention, and various kinds of additives can be used alone. Or they may be used in combination.

In addition, in the manufacturing method of the masterbatch of said (3), it is also possible to give the dispersion effect of the particle | grains at the time of masterbatch preparation, and a binder function by adding a resin additive to a masterbatch. . However, the resin additive may be added at any timing including when the master batch is created.
Although the specific example of the main thing is given to the following among each resin additive, it is not limited to these.

(5.2.1) Plasticizer The plasticizer is not particularly limited, but is a phosphate ester plasticizer, phthalate ester plasticizer, trimellitic ester plasticizer, pyromellitic acid plasticizer, glyco Examples thereof include rate plasticizers, citrate ester plasticizers, and polyester plasticizers.

  Examples of the phosphate plasticizer include triphenyl phosphate, tricresyl phosphate, cresyl diphenyl phosphate, octyl diphenyl phosphate, diphenyl biphenyl phosphate, trioctyl phosphate, tributyl phosphate, and the like.

  Examples of the phthalate ester plasticizer include diethyl phthalate, dimethoxyethyl phthalate, dimethyl phthalate, dioctyl phthalate, dibutyl phthalate, di-2-ethylhexyl phthalate, butyl benzyl phthalate, diphenyl phthalate, and dicyclohexyl phthalate. it can.

Examples of trimellitic acid plasticizers include tributyl trimellitate, triphenyl trimellitate, triethyl trimellitate, and the like.
Examples of the pyromellitic acid ester plasticizer include tetrabutyl pyromellitate, tetraphenyl pyromellitate, and tetraethyl pyromellitate.

  Examples of the glycolate plasticizer include triacetin, tributyrin, ethyl phthalyl ethyl glycolate, methyl phthalyl ethyl glycolate, butyl phthalyl butyl glycolate, and the like.

  Examples of the citrate plasticizer include triethyl citrate, tri-n-butyl citrate, acetyl triethyl citrate, acetyl tri-n-butyl citrate, acetyl tri-n- (2-ethylhexyl) citrate. Etc.

(5.2.2) Antioxidants Examples of antioxidants include phenolic antioxidants, phosphorus antioxidants, sulfur antioxidants, etc. Among them, phenolic antioxidants, particularly alkyl-substituted ones. Phenol antioxidants are preferred. By blending these antioxidants, it is possible to prevent lens coloration and strength reduction due to oxidative degradation during molding without reducing transparency, heat resistance, and the like. These antioxidants can be used alone or in combination of two or more, and the blending amount thereof is appropriately selected within a range not impairing the object of the present invention.

  Here, conventionally known phenolic antioxidants can be used, such as 2-t-butyl-6- (3-t-butyl-2-hydroxy-5-methylbenzyl) -4-methyl. Japanese Patent Application Laid-Open No. 63-179953 and other documents such as phenyl acrylate and 2,4-di-t-amyl-6- (1- (3,5-di-t-amyl-2-hydroxyphenyl) ethyl) phenyl acrylate Acrylate compounds described in Japanese Utility Model Publication No. 1-168643; octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 2,2'-methylene-bis (4-methyl-6) -T-butylphenol), 1,1,3-tris (2-methyl-4-hydroxy-5-t-butylphenyl) butane, pentaerythrityl-tetrakis [3- ( , 5-di-t-butyl-4-hydroxyphenyl) propionate], thiodiethylenebis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], 1,3,5-trimethyl- 2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, triethylene glycol bis (3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionate) Alkyl-substituted phenolic compounds such as 6- (4-hydroxy-3,5-di-t-butylanilino) -2,4-bisoctylthio-1,3,5-triazine, 4-bisoctylthio-1, Triazine group-containing phenols such as 3,5-triazine and 2-octylthio-4,6-bis- (3,5-di-t-butyl-4-oxyanilino) -1,3,5-triazine Compounds; and the like.

  In addition, the phosphorus antioxidant is not particularly limited as long as it is a substance usually used in the general resin industry. For example, triphenyl phosphite, diphenylisodecyl phosphite, phenyl diisodecyl phosphite, tris (nonyl) Phenyl) phosphite, tris (dinonylphenyl) phosphite, tris (2,4-di-t-butylphenyl) phosphite, tris- (2,6-dimethylphenyl) phosphite, 10- (3,5- Monophosphite compounds such as di-t-butyl-4-hydroxybenzyl) -9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide; 4,4′-butylidene-bis (3- Methyl-6-tert-butylphenyl-di-tridecyl phosphite), 4,4'-isopropylidene-bi (Phenyl - di - alkyl (C12-C15) phosphite), and the like diphosphite compounds such as. Among these, monophosphite compounds are preferable, and tris (nonylphenyl) phosphite, tris (dinonylphenyl) phosphite, tris (2,4-di-t-butylphenyl) phosphite and the like are particularly preferable.

  Examples of the sulfur-based antioxidant include dilauryl 3,3-thiodipropionate, dimyristyl 3,3'-thiodipropionate, distearyl 3,3-thiodipropionate, lauryl stearyl 3,3- Thiodipropionate, pentaerythritol-tetrakis- (β-lauryl-thio-propionate), 3,9-bis (2-dodecylthioethyl) -2,4,8,10-tetraoxaspiro [5,5] undecane Etc.

(5.2.3) Light Stabilizer Examples of the light stabilizer include benzophenone light stabilizer, benzotriazole light stabilizer, hindered amine light stabilizer, etc. In the present invention, the transparency of the lens, From the viewpoint of color resistance and the like, it is preferable to use a hindered amine light-resistant stabilizer (hereinafter referred to as HALS).

  In particular, among HALS, those having a Mn in terms of polystyrene measured by gel permeation chromatography (GPC) using tetrahydrofuran (THF) as a solvent are preferably 1,000 to 10,000, and 2,000 to What is 5,000 is more preferable, and what is 2,800-3,800 is especially preferable. If Mn is too small, volatility may occur when HALS is melted and kneaded with a cyclic olefin resin in a masterbatch manufacturing process, or when melted and kneaded with a thermoplastic resin in the composite material manufacturing process. Therefore, a predetermined amount cannot be blended, and processing stability is lowered, for example, foaming or silver streak occurs during heat-melt molding such as injection molding. Further, when a lens is molded from a composite material, if the lens is used for a long time with the lamp turned on, a volatile component is generated as a gas from the lens. Conversely, if Mn is too large, when a lens is molded from a composite material, the dispersibility of the lens in a cyclic olefin resin or a thermoplastic resin is lowered, the transparency of the lens is lowered, and the effect of improving light resistance is reduced. To do. Therefore, in the present invention, a lens having excellent processing stability, low gas generation and transparency can be obtained by setting the HALS Mn within the above range.

  Specific examples of such HALS include N, N ′, N ″, N ′ ″-tetrakis- [4,6-bis- {butyl- (N-methyl-2,2,6,6-tetramethylpiperidine. -4-yl) amino} -triazin-2-yl] -4,7-diazadecane-1,10-diamine, dibutylamine and 1,3,5-triazine and N, N'-bis (2,2,6 , 6-tetramethyl-4-piperidyl) butylamine, poly [{(1,1,3,3-tetramethylbutyl) amino-1,3,5-triazine-2,4-diyl} { (2,2,6,6-tetramethyl-4-piperidyl) imino} hexamethylene {(2,2,6,6-tetramethyl-4-piperidyl) imino}], bis (2,2,6,6 -Tetramethyl-4-piperidyl) sebacate, 1,6-hexanediamy A polycondensate of -N, N'-bis (2,2,6,6-tetramethyl-4-piperidyl) and morpholine-2,4,6-trichloro-1,3,5-triazine, poly [ (6-morpholino-s-triazine-2,4-diyl) (2,2,6,6, -tetramethyl-4-piperidyl) imino] -hexamethylene [(2,2,6,6-tetramethyl- 4-piperidyl) imino] and other high molecular weight HALS in which a plurality of piperidine rings are bonded via a triazine skeleton; polymerization of dimethyl succinate with 4-hydroxy-2,2,6,6-tetramethyl-1-piperidineethanol 1,2,3,4-butanetetracarboxylic acid, 1,2,2,6,6-pentamethyl-4-piperidinol and 3,9-bis (2-hydroxy-1,1-dimethylethyl) -2 , 4, 8, Examples include high molecular weight HALS in which piperidine rings are bonded via an ester bond, such as a mixed esterified product with 10-tetraoxaspiro [5,5] undecane.

  Among these, polycondensates of dibutylamine, 1,3,5-triazine and N, N′-bis (2,2,6,6-tetramethyl-4-piperidyl) butylamine, poly [{(1, 1,3,3-tetramethylbutyl) amino-1,3,5-triazine-2,4-diyl} {(2,2,6,6-tetramethyl-4-piperidyl) imino} hexamethylene {(2 , 2,6,6-tetramethyl-4-piperidyl) imino}], a polymer of dimethyl succinate and 4-hydroxy-2,2,6,6-tetramethyl-1-piperidineethanol and the like. 5,000 to 5,000 are preferred.

(6) Molded body production method There are no particular restrictions on the production method of molded articles such as optical elements using the above composite materials, but it has characteristics such as low birefringence, mechanical strength, and dimensional accuracy. From the viewpoint of obtaining an excellent molded product, the melt molding method is preferable.
Examples of the melt molding method include a press molding method, an extrusion molding method, and an injection molding method. The injection molding method is preferable from the viewpoints of moldability and productivity.

  In addition, the molding conditions are appropriately selected depending on the purpose of use or the molding method. For example, the temperature of the composite material in the injection molding method is to impart appropriate fluidity to the resin at the time of molding to reduce sink marks and distortion of the molded product. In view of preventing silver streak due to thermal decomposition of the resin and effectively preventing yellowing of the molded product, a range of 150 ° C. to 400 ° C. is preferable, and 200 ° C. to 350 ° C. is more preferable. It is the range of 200 degreeC, Especially preferably, it is the range of 200 to 330 degreeC.

  The molded product thus produced can be used in various forms such as a spherical shape, a rod shape, a plate shape, a cylindrical shape, a tubular shape, a tubular shape, a fibrous shape, a film shape, or a sheet shape. In addition, since this molded product is excellent in low birefringence, transparency, mechanical strength, heat resistance, and low water absorption, it can be used as an optical resin lens that is one of the optical elements according to the present invention. It is also suitably used as other optical components.

(7) Application Example of Molded Body as Optical Element As a specific application example of the molded body obtained by the above manufacturing method to an optical element, for example, an optical lens or an optical prism, a microscope, an endoscope, a telescope Lenses such as lenses, fθ lenses for laser beam printers, laser scanning lenses such as sensor lenses, imaging lenses for cameras, prism lenses for viewfinders, all-light transmission lenses such as eyeglass lenses, pickup lenses for optical disks, etc. Is mentioned.

  As optical disks, CD, CD-ROM, WORM (write-once optical disk), MO (rewritable magneto-optical disk), MD (MiniDisc), DVD (Digital Versatile Disc), BD (Blu-ray Disc), AOD (advanced optical disc) etc. are mentioned.

  Other application examples as optical elements include optical films such as polarizing films, retardation films and light diffusion films, light diffusion plates, optical cards, liquid crystal display element substrates, light guide plates such as liquid crystal displays, and the like. .

  Among these, a pickup lens and a laser scanning system lens that require low birefringence are preferable, and a pickup lens is most preferable. This is because the optical element produced using the master batch according to the present invention has excellent temperature characteristics and is suitably used as a pickup lens for a high-density optical disk using a blue-violet laser light source.

(7.1) Application Example as Pickup Lens Hereinafter, an optical pickup device 1 in which the optical element in the present embodiment is used as an objective lens will be described with reference to FIG.

  As shown in FIG. 1, the optical pickup device 1 in this embodiment includes three types of semiconductor laser oscillators LD1, LD2, and LD as light sources. Among these, the semiconductor laser oscillator LD1 emits a light beam having a specific wavelength of 350 to 450 nm, for example, 405 nm and 407 nm, for the BD (or AOD) 10. Further, the semiconductor laser oscillator LD2 emits a light beam having a specific wavelength in a wavelength of 620 to 680 nm for the DVD 20. Further, the semiconductor laser LD3 emits a light beam having a specific wavelength in the range of 750 to 810 nm for the CD30.

  In the optical axis direction of the blue light emitted from the semiconductor laser oscillator LD1, a shave SH1, a splitter BS1, a collimator CL, splitters BS4 and BS5, and an objective lens 15 are sequentially arranged from the lower side to the upper side in FIG. The optical information recording medium BD10, DVD20 or CD30 is arranged at a position facing the objective lens 15. Further, a cylindrical lens L11, a concave lens L12, and a photodetector PD1 are sequentially disposed on the right side of the splitter BS1 in FIG.

  In the optical axis direction of the red light emitted from the semiconductor laser oscillator LD2, splitters BS2 and BS4 are sequentially arranged from the left to the right in FIG. Further, a cylindrical lens L21, a concave lens L22, and a photodetector PD2 are sequentially disposed below the splitter BS2 in FIG.

  In the optical axis direction of the light emitted from the semiconductor laser oscillator LD3, splitters BS3 and BS5 are sequentially arranged from the right to the left in FIG. A cylindrical lens L31, a concave lens L32, and a photodetector PD3 are sequentially arranged below the splitter BS3 in FIG.

  The objective lens 15 as an optical element according to the present invention is disposed opposite to the BD10, DVD20 or CD30 as an optical information recording medium, and the light emitted from each of the semiconductor laser oscillators LD1, LD2 and LD3 is BD10. The light is condensed on the DVD 20 or the CD 30. Such an objective lens 15 includes a two-dimensional actuator 2, and the objective lens 15 is movable in the vertical direction by the operation of the two-dimensional actuator 2.

Next, the operation of the optical pickup device 1 will be described.
Since the optical pickup device 1 in the present embodiment operates differently depending on the type of the optical information recording medium, details of operation modes for the BD 10, the DVD 20 and the CD 30 will be described below.

First, the operation of the optical pickup device 1 with respect to the BD 10 will be described.
The semiconductor laser oscillator LD1 emits light at the time of recording information on the BD 10 or at the time of reproducing information recorded on the BD 10. As shown in FIG. 1, the light becomes a light beam L1, is shaped by passing through the shave SH1, passes through the splitter BS1, and is collimated by the collimator CL. Then, it passes through each of the splitters BS4 and BS5 and the objective lens 15, and forms a condensed spot on the recording surface 10a of the BD10.

  The light that forms the condensed spot is modulated by the information pits on the recording surface 10a of the BD 10 and reflected by the recording surface 10a. The reflected light passes through the objective lens 15, the splitters BS5 and BS4, and the collimator CL, is reflected by the splitter BS1, and then passes through the cylindrical lens L11 to give astigmatism. Thereafter, this light passes through the concave lens L12 and is received by the photodetector PD1. Thereafter, such an operation is repeatedly performed, and the operation of recording information on the BD 10 and the operation of reproducing information recorded on the BD 10 are completed.

Next, the operation of the optical pickup device 1 for the DVD 20 will be described.
The semiconductor laser oscillator LD2 emits light at the time of recording information on the DVD 20 or at the time of reproducing information recorded on the DVD 20. As shown in FIG. 1, the light becomes a light beam L2, passes through the splitter BS2, and is reflected by the splitter BS4. The reflected light beam L2 passes through the splitter BS5 and the objective lens 15, and forms a condensed spot on the recording surface 20a of the DVD 20.

  The light forming the condensed spot is modulated by the information pits on the recording surface 20a of the DVD 20 and reflected by the recording surface 20a. The reflected light is transmitted through the objective lens 15 and the splitter BS5, reflected by the splitters BS4 and BS2, and then transmitted through the cylindrical lens L21 to give astigmatism. Thereafter, this light passes through the concave lens L22 and is received by the photodetector PD2. Thereafter, such an operation is repeatedly performed, and the operation of recording information on the DVD 20 and the operation of reproducing information recorded on the DVD 20 are completed.

Finally, the operation of the optical pickup device 1 for the CD 30 will be described.
Light is emitted from the semiconductor laser oscillator LD3 when information is recorded on the CD 30 or when information recorded on the CD 30 is reproduced. As shown in FIG. 1, the emitted light becomes a light beam L3, passes through the splitter BS3, and is reflected by the splitter BS5. The reflected light beam L3 passes through the objective lens 15 and forms a condensed spot on the recording surface 30a of the CD 30.

  The light forming the focused spot is modulated by the information pits on the recording surface 30a of the CD 30, and reflected by the recording surface 30a. The reflected light is transmitted through the objective lens 15, reflected by the splitters BS5 and BS3, and then transmitted through the cylindrical lens L31 to give astigmatism. Thereafter, this light passes through the concave lens L32 and is received by the photodetector PD3. Thereafter, such an operation is repeatedly performed, and the recording operation of information on the CD 30 and the reproducing operation of information recorded on the CD 30 are completed.

  The optical pickup device 1 is configured to detect spots of the light detectors PD1, PD2, and PD3 at the time of recording information on the BD 10, DVD 20, or CD 30, and at the time of reproducing information recorded on the BD 10, DVD 20, or CD 30. Intensity detection or track detection is performed by detecting a change in light amount due to a shape change or a position change. In such an optical pickup device 1, the two-dimensional actuator 2 transmits the light from the semiconductor laser oscillators LD1, LD2, and LD3 to the BD10, DVD20, or CD30 based on the detection results of the photodetectors PD1, PD2, and PD3. The objective lens 15 is moved so as to form an image on the recording surfaces 10a, 20a, and 30a, and the light from the semiconductor laser oscillators LD1, LD2, and LD3 is formed on predetermined tracks on the recording surfaces 10a, 20a, and 30a. The objective lens 15 is moved.

  According to the objective lens 15 in the optical pickup device 1 described above, when the inorganic fine particles are mixed in the resin, the volume average dispersed particle size of the inorganic fine particles is 30 nm or less, so compared with the conventional case where the fine particles are larger than 30 nm. Thus, the transparency of the objective lens can be increased.

  Moreover, in the manufacturing process of the master batch for the objective lens 15, since the cyclic olefin resin and the inorganic fine particles are mixed in a wet manner, scattering of the inorganic fine particles during mixing is prevented. Accordingly, since the inorganic fine particles can be stably supplied into the cyclic olefin resin, the composition of the objective lens 15 obtained by molding the composite material using the master batch can be made uniform.

  Hereinafter, the optical element according to the present invention will be described more specifically by giving examples and comparative examples. However, the present invention is not limited to the examples.

以下、これら実施例（１）〜（７）及び比較例（１）〜（６）について詳細に説明する。 As examples and comparative examples of the optical element according to the present invention, Examples (1) to (7) and Comparative Examples (1) to (6) were prepared as shown in Table 1 below.

Hereinafter, these Examples (1) to (7) and Comparative Examples (1) to (6) will be described in detail.

<Example (1)>
Using “TK Hibis Disper Mix 3D-20” (product name, manufactured by Tokushu Kika Kogyo Co., Ltd.), 95 parts by weight of cyclic olefin resin “ZEONEX330R” (product name, manufactured by Nippon Zeon), gas phase process SiO ₂ “ RX300 "(product name, manufactured by Nippon Aerosil Co., Ltd., volume average dispersed particle size 7 nm) 100 parts by weight and cyclohexane (Kanto Chemical Co., Ltd.) 500 parts by weight were wet mixed at 85 ° C., followed by devolatilization and drying. Such a master batch was obtained. In this master batch, the content of inorganic fine particles is 50 parts by volume with respect to 100 parts by volume of the cyclic olefin resin.

Next, using a polylab system (manufactured by Eiko Seiki), the master batch and ZEONEX330R were melt-kneaded at a ratio such that the SiO ₂ particles were 30 vol%, and the composite material was obtained, and then the composite material was injected. It shape | molded with the molding machine and Example (1) was created as an optical element for optical evaluation.

<Example (2)>
Using “TK Hibis Disper Mix 3D-20” (product name, manufactured by Tokushu Kika Kogyo Co., Ltd.), 95 parts by weight of cyclic olefin resin “ZEONEX330R” (product name, manufactured by Nippon Zeon), gas phase process SiO ₂ “ RX200 "(product name, manufactured by Nippon Aerosil Co., Ltd., volume average dispersed particle size 12 nm) 50 parts by weight and cyclohexane (Kanto Chemical Co., Ltd.) 1000 parts by weight were wet mixed at 85 ° C., then devolatilized and dried to obtain the present invention. Such a master batch was obtained. In this master batch, the content of the inorganic fine particles is 25 parts by volume with respect to 100 parts by volume of the cyclic olefin resin.

Next, using a polylab system (manufactured by Eihiro Seiki), the master batch and ZEONEX330R are melt-kneaded at a ratio such that SiO ₂ particles are 20 vol%, and then the composite material is obtained, and then the composite material is injected. It shape | molded with the molding machine and Example (2) was created as an optical element for optical evaluation.

<Example (3)>
Using “TK Hibis Disper Mix 3D-20” (product name, manufactured by Tokushu Kika Kogyo Co., Ltd.), 95 parts by weight of cyclic olefin resin “ZEONEX330R” (product name, manufactured by Nippon Zeon), gas phase process SiO ₂ “ RX200 "(product name, manufactured by Nippon Aerosil Co., Ltd., volume average dispersed particle size 12 nm) 240 parts by weight and xylene (manufactured by Kanto Chemical) 500 parts by weight were wet-mixed at 95 ° C., and then devolatilized and dried. Such a master batch was obtained. In this master batch, the content of the inorganic fine particles is 120 parts by volume with respect to 100 parts by volume of the cyclic olefin resin.

Next, using a polylab system (manufactured by Eiko Seiki), the master batch and ZEONEX330R were melt-kneaded at a ratio such that the SiO ₂ particles were 30 vol%, and the composite material was obtained, and then the composite material was injected. It shape | molded with the molding machine and Example (3) was created as an optical element for optical evaluation.

<Example (4)>
Using “TK Hibis Disper Mix 3D-20” (product name, manufactured by Tokushu Kika Kogyo Co., Ltd.), 104 parts by weight of cyclic olefin resin “APEL5014” (product name, manufactured by Mitsui Chemicals), gas phase SiO ₂ “ RX300 "(product name, manufactured by Nippon Aerosil Co., Ltd., volume average dispersion particle size 7 nm) 100 parts by weight, cyclohexane (Kanto Chemical Co., special grade) 100 parts by weight and tetrahydrofuran (Kanto Chemical Co., special grade) 100 parts by weight are wet mixed at 95 ° C. Then, devolatilization and drying were performed to obtain a master batch according to the present invention. In this master batch, the content of inorganic fine particles is 50 parts by volume with respect to 100 parts by volume of the cyclic olefin resin.

Next, using a polylab system (manufactured by Eiko Seiki), the master batch and ZEONEX330R were melt-kneaded at a ratio such that the SiO ₂ particles were 30 vol%, and the composite material was obtained, and then the composite material was injected. It shape | molded with the molding machine and Example (4) was created as an optical element for optical evaluation.

<Example (5)>
Using “TK Hibis Disper Mix 3D-20” (product name, manufactured by Tokushu Kika Kogyo Co., Ltd.), 104 parts by weight of cyclic olefin resin “APEL5014” (product name, manufactured by Mitsui Chemicals), alumina “TM-3000” After wet mixing at 95 ° C. with 100 parts by weight (product name, manufactured by Daimei Chemical, volume average dispersed particle size 7 nm), 400 parts by weight of cyclohexane (manufactured by Kanto Chemical, special grade) and 100 parts by weight of tetrahydrofuran (manufactured by Kanto Chemical, special grade) Then, devolatilization and drying were performed to obtain a master batch according to the present invention. In this master batch, the content of inorganic fine particles is 50 parts by volume with respect to 100 parts by volume of the cyclic olefin resin.

Next, using a polylab system (manufactured by Eiko Seiki), the master batch and ZEONEX330R were melt-kneaded at a ratio such that the SiO ₂ particles were 30 vol%, and the composite material was obtained, and then the composite material was injected. It shape | molded with the molding machine and Example (5) was created as an optical element for optical evaluation.

<Example (6)>
By using “NanoCreator” (manufactured by Hosokawa Micron), SiO ₂ / ZrO by reacting the raw material gas stream prepared from two metal components Si and Zn and oxygen gas into the reaction space of high temperature atmosphere. ₂ composite particles were obtained. As a result of TEM / EDX observation, the composite particles had a volume average dispersed particle size of 20 nm, a uniform composition, and the volume ratio of SiO ₂ to ZrO ₂ was 22.5: 8.6.

Subsequently, 95 parts by weight of cyclic olefin resin “ZEONEX330R” (product name, manufactured by Nippon Zeon Co., Ltd.) using “TK Hibis Disper Mix 3D-20” (product name, manufactured by Tokushu Kika Kogyo Co., Ltd.), SiO ₂ / ZrO ₂ composite particles (volume average dispersed particle size 20 nm) 224 parts by weight and cyclohexane (manufactured by Kanto Chemical) 500 parts by weight were wet mixed at 85 ° C., then devolatilized and dried, and the master batch according to the present invention was prepared. Obtained. In this master batch, the content of inorganic fine particles is 50 parts by volume with respect to 100 parts by volume of the cyclic olefin resin.

  Next, using the polylab system (manufactured by Eihiro Seiki), the master batch and ZEONEX330R are melt-kneaded at a ratio such that the composite particles become 30 vol%, and then the composite material is obtained. Then, the composite material is injection molded. Example (6) was produced as an optical element for optical evaluation.

<Example (7)>
A mixed solution of 463.1 g of pure water, 104.8 g of 26% ammonia water and 4255.0 g of methanol, a mixed solution of 3192 g of tetramethoxysilane (TMOS) and 229.4 g of methanol, 643.2 g of pure water and 26% ammonia water 104.8 g of the mixed solution was added dropwise over 150 minutes while maintaining the liquid temperature at 25 ° C., and then a mixed solution of 3409 g of titanium tetraisopropoxide and 150 g of isopropyl alcohol was added over 100 minutes, and SiO ₂ / TiO _{2 was} added. _Two composite sols were obtained. The sol was distilled by heating under normal pressure, and pure water was added dropwise while keeping the volume constant. When it was confirmed that the top temperature of the distillation tower reached 100 ° C. and the pH became 8 or less, pure water was used. The dropping was finished to obtain a dispersion of inorganic particles.

Further, 15.4 g of methyltrimethoxysilane was added and stirred at room temperature for 1 hour, and then refluxed for 2 hours. Then, methyl ethyl ketone was added dropwise while keeping the volume constant by heating and distillation under normal pressure, and the addition was terminated when it was confirmed that the tower top temperature reached 79 ° C. and the water content was 1.0% or less. After cooling to room temperature, microfiltration was performed using a 3 μ membrane filter to obtain a methyl ethyl ketone-dispersed SiO ₂ / TiO ₂ composite sol. Thereafter, the solvent was distilled off under reduced pressure to obtain SiO ₂ / TiO ₂ composite particles that had been surface-treated. As a result of TEM / EDX observation, the volume dispersion average particle diameter was 11 nm. Moreover, the SiO ₂ / TiO ₂ composition ratio (volume fraction) of the outer surface portion was 100/0, and it was a core-shell type composite particle in which the composition ratio of TiO ₂ increased toward the center portion.

Subsequently, 95 parts by weight of cyclic olefin resin “ZEONEX330R” (product name, manufactured by Nippon Zeon Co., Ltd.) using “TK Hibis Disper Mix 3D-20” (product name, manufactured by Tokushu Kika Kogyo Co., Ltd.), SiO ₂ / TiO ₂ composite particles (volume average dispersed particle size 11 nm) 120 parts by weight and cyclohexane (manufactured by Kanto Chemical) 500 parts by weight were wet mixed at 85 ° C., then devolatilized and dried, and the master batch according to the present invention was prepared. Obtained. In this master batch, the content of inorganic fine particles is 50 parts by volume with respect to 100 parts by volume of the cyclic olefin resin.

  Next, using the polylab system (manufactured by Eihiro Seiki), the master batch and ZEONEX330R are melt-kneaded at a ratio such that the composite particles become 30 vol%, and then the composite material is obtained. Then, the composite material is injection molded. Example (7) was created as an optical element for optical evaluation.

<Comparative Example (1)>
Using a 20 L super mixer, 95 parts by weight of cyclic olefin resin “ZEONEX330R” (product name, manufactured by ZEON CORPORATION) and gas phase SiO ₂ “RX300” (product name, manufactured by Nippon Aerosil Co., Ltd., volume average dispersed particle size: 7 nm) 100 Part by weight was dry mixed to obtain a powder mixture. In this powder mixture, the content of inorganic fine particles with respect to 100 parts by volume of the cyclic olefin resin is 50 parts by volume.

Next, using a polylab system (manufactured by Eiko Seiki), the powder mixture and ZEONEX330R were melt-kneaded at a ratio such that the SiO ₂ particles were 30 vol%, and then the composite material was obtained. It molded with the injection molding machine and the comparative example (1) was created as an optical element for optical evaluation.

<Comparative Example (2)>
Using a twin screw extruder “2D25-S type 20 mmφ” (product name, manufactured by Toyo Seiki Seisakusho Co., Ltd.), 95 parts by weight of cyclic olefin resin “ZEONEX330R” (product name, manufactured by Nippon Zeon Co., Ltd.), and gas phase process SiO ₂ “ 100 parts by weight of “RX200” (product name, manufactured by Nippon Aerosil Co., Ltd.) (volume average dispersed particle size 12 nm) was melt extruded at 220 ° C. to obtain a master batch. In this master batch, the content of inorganic fine particles is 50 parts by volume with respect to 100 parts by volume of the cyclic olefin resin.

Next, using a polylab system (manufactured by Eiko Seiki), the master batch and ZEONEX330R were melt-kneaded at a ratio such that the SiO ₂ particles were 30 vol%, and the composite material was obtained, and then the composite material was injected. It shape | molded with the molding machine and the comparative example (2) was created as an optical element for optical evaluation.

<Comparative Example (3)>
Using “TK Hibis Disper Mix 3D-20” (product name, manufactured by Tokushu Kika Kogyo Co., Ltd.), 95 parts by weight of cyclic olefin resin “ZEONEX330R” (product name, manufactured by Nippon Zeon), gas phase process SiO ₂ “ RX300 "(product name, manufactured by Nippon Aerosil Co., Ltd., volume average dispersed particle size 7 nm) 660 parts by weight and cyclohexane (manufactured by Kanto Chemical) 500 parts by weight were wet mixed at 85 ° C, then devolatilized and dried to obtain a master batch. It was. In this master batch, the content of the inorganic fine particles is 330 parts by volume with respect to 100 parts by volume of the cyclic olefin resin.

Next, using a polylab system (manufactured by Eiko Seiki), the master batch and ZEONEX330R were melt-kneaded at a ratio such that the SiO ₂ particles were 30 vol%, and the composite material was obtained, and then the composite material was injected. It shape | molded with the molding machine and the comparative example (3) was created as an optical element for optical evaluation. That is, the comparative example (3) is created by the same production process as the above-described example (1) except that 100 parts by weight of “RX300” is changed to 660 parts by weight.

<Comparative Example (4)>
Using “TK Hibis Disper Mix 3D-20” (product name, manufactured by Tokushu Kika Kogyo Co., Ltd.), 95 parts by weight of cyclic olefin resin “ZEONEX330R” (product name, manufactured by Nippon Zeon), gas phase process SiO ₂ “ A50 ”(product name, manufactured by Nippon Aerosil Co., Ltd., BET specific surface area 50 m ² / g, volume average dispersed particle size 40 nm) 100 parts by weight and cyclohexane (manufactured by Kanto Chemical) 500 parts by weight were wet mixed at 85 ° C. Drying was performed to obtain a master batch. In this master batch, the content of inorganic fine particles is 50 parts by volume with respect to 100 parts by volume of the cyclic olefin resin.

Next, using a polylab system (manufactured by Eiko Seiki), the master batch and ZEONEX330R were melt-kneaded at a ratio such that the SiO ₂ particles were 30 vol%, and the composite material was obtained, and then the composite material was injected. It shape | molded with the molding machine and the comparative example (4) was created as an optical element for optical evaluation. That is, the comparative example (4) is created by the same production process as the above-described example (1) except that “RX300” is set to “A50”.

<Comparative Example (5)>
Using “TK Hibis Disper Mix 3D-20” (product name, manufactured by Tokushu Kika Kogyo Co., Ltd.), 95 parts by weight of cyclic olefin resin “ZEONEX330R” (product name, manufactured by Nippon Zeon), gas phase process SiO ₂ “ RX300 "(product name, manufactured by Nippon Aerosil Co., Ltd., volume average dispersed particle size 7 nm) 40 parts by weight and cyclohexane (Kanto Chemical Co., Ltd.) 500 parts by weight were wet mixed at 85 ° C, then devolatilized and dried to prepare a master batch. Obtained. In this master batch, the content of inorganic fine particles is 20 parts by volume with respect to 100 parts by volume of the cyclic olefin resin.

Next, using a polylab system (manufactured by Eihiro Seiki), the master batch and ZEONEX330R were melt-kneaded at a ratio such that the SiO ₂ particles would be 10 vol% to obtain the composite material, and then the composite material was injected. It shape | molded with the molding machine and the comparative example (5) was created as an optical element for optical evaluation.

<Comparative Example (6)>
Using "TK Hibis Disper Mix 3D-20" (product name, manufactured by Tokushu Kika Kogyo Co., Ltd.), 95 parts by weight of cyclic olefin resin "ZEONEX330R" (product name, manufactured by Nippon Zeon) and cyclohexane (manufactured by Kanto Chemical) After 500 parts by weight of wet mixing at 85 ° C., devolatilization and drying were performed to obtain a master batch. In this master batch, the content of the inorganic fine particles is 100 parts by volume with respect to 100 parts by volume of the cyclic olefin resin.

Next, using a polylab system (manufactured by Eiko Seiki), the master batch and ZEONEX330R were melt-kneaded at a ratio such that the SiO ₂ particles were 30 vol%, and the composite material was obtained, and then the composite material was injected. It shape | molded with the molding machine and the comparative example (6) was created as an optical element for optical evaluation. That is, the comparative example (6) is created by the same production process as the above-described example (1) except that “RX300” is not used.

  The light transmittance and the linear expansion coefficient were measured as follows for Examples (1) to (7) and Comparative Examples (1) to (6). The results are shown in Table 1 above.

(Measurement of light transmittance)
Using a spectrophotometer UV-3150 manufactured by Shimadzu Corporation as a measuring device, a wavelength of 405 nm with respect to the thickness direction (1 mm thickness) of Examples (1) to (7) and Comparative Examples (1) to (6) The light transmittance was measured according to ASTM D-1003.

(Measurement of linear expansion coefficient)
CN8098F1 manufactured by Rigaku Corporation was used as a measuring device, and the average linear expansion coefficients of Examples (1) to (7) and Comparative Examples (1) to (6) were measured according to JIS R3102.

As is clear from the results shown in Table 1, it can be seen that the optical element of Example (1) has higher transparency to blue light having a wavelength of 405 nm than the optical elements of Comparative Examples (1) to (5). . Moreover, since the linear expansion coefficient is small, it turns out that the composition is equalized.
Note that the optical element of Comparative Example (6) has an excessively large thermal expansion coefficient and is not suitable for practical use, and thus is not suitable as a comparative control for Examples (1) to (7).

It is a figure which shows schematic structure of an optical pick-up apparatus.

Explanation of symbols

15 Objective lens (optical element)

Claims (8)

A cyclic olefin resin;
Inorganic fine particles having a volume average dispersed particle size of 30 nm or less are mixed as a main component in a wet manner,
Content of the said inorganic fine particle is 20 volume parts or more and 300 volume parts or less with respect to 100 volume parts of the said cyclic olefin resin, The masterbatch characterized by the above-mentioned.   The master batch according to claim 1, wherein the inorganic fine particles contain at least silicon oxide.   The master batch according to claim 1 or 2, wherein the inorganic fine particles include metal oxide fine particles containing at least two or more different metal atoms.   An optical element formed by molding a composite material of the master batch according to any one of claims 1 to 3 and a thermoplastic resin. Comprising a mixing step in which a cyclic olefin resin and inorganic fine particles having a volume average dispersed particle size of 30 nm or less are mixed as a main component in a wet manner;
In this mixing process,
Content of the said inorganic fine particle shall be 20 volume part or more and 300 volume part or less with respect to 100 volume part of said cyclic olefin resin, The manufacturing method of the masterbatch characterized by the above-mentioned.   6. The method for producing a masterbatch according to claim 5, wherein the inorganic fine particles contain at least silicon oxide.   The method for producing a masterbatch according to claim 5 or 6, wherein the inorganic fine particles include metal oxide fine particles containing at least two or more different metal atoms.   It includes a molding step for forming an optical element by molding a composite material of a master batch produced by the method for producing a master batch according to any one of claims 5 to 7 and a thermoplastic resin. A method for manufacturing an optical element.

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