JP2006328261A - Inorganic fine particle dispersed composition, thermoplastic resin composition, and optical element - Google Patents

Abstract

[PROBLEMS] To easily and uniformly disperse a large amount of inorganic fine particles in an olefinic resin having no polar group, and to obtain temperature dependence of transparency and refractive index in the obtained thermoplastic resin composition and optical element. To improve.
An inorganic material containing at least one of 0.1 to 20 parts by weight of an olefin resin and 0.1 to 10 parts by weight of a resin additive, 100 parts by weight of inorganic fine particles, and 5 to 20 parts by weight of a surface treatment agent. A fine particle dispersion composition and a cyclic polyolefin resin are mixed to produce a thermoplastic resin composition, and an optical element is produced using the thermoplastic resin composition.
[Selection] Figure 1

Description

  The present invention relates to an inorganic fine particle dispersion composition, a thermoplastic resin composition, and an optical element, and particularly suitably used as a lens, a filter, a grating, an optical fiber, a flat optical waveguide, etc., and has high thermal stability and transparency. The present invention relates to an excellent inorganic fine particle dispersion composition, a thermoplastic resin composition, and an optical element.

  Information devices such as MO (Magneto Optics), CD (Compact Disc), DVD (Digital Versatile Disc), and other information devices such as players, recorders, and drives that perform information reading operations and recording operations include: An optical pickup device is provided. This optical pickup device is provided with an optical element unit that irradiates a medium with light of a predetermined wavelength emitted from a light source and receives the reflected light by a light receiving element. The optical element unit receives these lights. An optical element such as a lens for condensing light by a reflection layer of the medium or a light receiving element is provided.

  For the optical element of the optical pickup device described above, it is preferable to apply plastic as a material from the viewpoint that it is possible to reduce the manufacturing cost by means such as injection molding. Known plastics include copolymers of cyclic olefins and α-olefins.

By the way, conventionally, research and development for improving physical properties such as rigidity or heat resistance by mixing fillers such as inorganic fine particles with a resin material have been actively conducted.
Therefore, using this method, as a thermoplastic resin composition capable of improving physical properties, a polyolefin resin as an optical material is filled with a layered silicate that has been subjected to an organic treatment with an alkylammonium salt. A polyolefin-based composite material has been developed (see, for example, Patent Document 1).

  In addition, as a thermoplastic resin composition capable of improving transparency, after surface treatment is performed on an oxidized compound having a polar group and a part of a hydrophobic group on the surface, it is dispersed in a solvent solution, A resin composition in which an olefin resin having a polar group is mixed has been developed (for example, see Patent Document 2).

  Furthermore, even when the inorganic filler is contained in a large amount, an olefin resin as a thermoplastic resin composition capable of uniformly dispersing the inorganic filler as a whole when mixed with the main material. And the rubber component, the inorganic filler, and the acid-modified resin, and the total amount of the olefin resin, the rubber component, the inorganic filler, and the acid-modified resin is 100 parts by mass, the acid-modified resin is 0. A master batch to be mixed so as to be 2 to 5 parts by mass has been developed (for example, see Patent Document 3).

Japanese Patent Laid-Open No. 10-30039 JP 2004-155942 A JP 2004-149565 A

However, in the case of the thermoplastic resin composition described in Patent Document 1 described above, there is a problem that improvement in physical properties accompanied by filler filling is insufficient and it is difficult to obtain sufficient dispersibility as a composite material. ing.
In addition, in the case of the thermoplastic resin composition described in Patent Document 2, since the inorganic fine particle solution used is expensive and has poor storage stability, there arises a problem that the production cost is increased and the production efficiency is lowered. ing. In addition, since the solvent removal step is included in the production process, there is a problem that it is not suitable for producing a thermoplastic resin composition highly filled with a filler.
Furthermore, in the case of the thermoplastic resin composition described in Patent Document 3, there is no specific description regarding the surface treatment method for the inorganic fine particles, and no mention is made of the optical characteristics thereof, so that it can be applied to optical applications. Whether or not there is any is completely unknown.
Thus, at present, a polyolefin-based thermoplastic resin composition optimal for optical applications has not been obtained.

  The present invention has been made in view of the above points, and has improved inorganic particle dispersibility with respect to olefinic resins, and has excellent inorganic particle dispersion composition and thermoplastic resin composition excellent in temperature dependency of transparency and refractive index. An object is to provide an object and an optical element.

  In order to solve the above problems, the inorganic fine particle dispersion composition according to the invention described in claim 1 includes at least one of 0.1 to 20 parts by weight of an olefin resin and 0.1 to 10 parts by weight of a resin additive. And 100 parts by weight of inorganic fine particles and 5 to 20 parts by weight of a surface treatment agent.

  According to the invention of claim 1, the resin additive added together with the inorganic fine particles acts as a binder with the olefin resin, thereby improving the compatibility of the inorganic fine particles with the olefin resin, Inorganic fine particles can be easily dispersed during kneading. Moreover, with the improvement of the dispersibility of inorganic fine particles, the light transmittance and the linear expansion coefficient can be improved.

  The inorganic fine particle dispersion composition according to the invention of claim 2 is characterized in that the olefin-based resin has a polar group and is compatible with the thermoplastic resin to be mixed.

  According to the invention described in claim 2, by using the olefin resin having a polar group, the bonding between the olefin resin as the host material and the inorganic fine particles is improved, and the surface treatment agent and the inorganic fine particles are A uniformly dispersed thermoplastic resin composition can be obtained.

  The inorganic fine particle dispersion composition according to the invention of claim 3 is characterized in that the resin additive contains at least one of a fatty acid amide and a fatty acid ester.

  According to the invention described in claim 3, by using a fatty acid amide and a fatty acid ester having a polar group, the bond between the olefin resin as the host material and the inorganic fine particles can be improved, and the surface treatment agent and the inorganic A thermoplastic resin composition in which fine particles are uniformly dispersed can be obtained.

  The inorganic fine particle dispersion composition according to the invention of claim 4 is characterized in that the inorganic fine particles have an average particle size of 30 nm or less.

  According to the invention described in claim 4, the dispersibility of the inorganic fine particles in the olefin resin can be improved, and the occurrence of light scattering due to the inorganic fine particles can be suppressed.

  The inorganic fine particle dispersion composition according to claim 5 is characterized in that the surface treatment agent is at least one of a silane coupling agent and a titanium coupling agent.

  According to the fifth aspect of the present invention, the surface of the inorganic fine particles is uniformly surface-treated by at least one of the silane coupling agent and the titanium coupling agent mixed in advance. Localization can be prevented and the dispersibility of the inorganic fine particles in the olefin resin can be improved.

  The inorganic fine particle dispersion composition according to the invention of claim 6 is obtained by uniformly mixing at least one of the olefin resin and the resin additive, the inorganic fine particles, and the surface treatment agent in a solvent, and then drying. It is created by performing processing.

  According to the sixth aspect of the present invention, even if the inorganic fine particles are likely to be aggregated when the solvent is removed, the occurrence of aggregation can be suppressed by the action of the surface treatment agent blended in advance.

  A thermoplastic resin composition according to the invention described in claim 7 is prepared by mixing the inorganic fine particle dispersion composition according to any one of claims 1 to 6 and a cyclic polyolefin resin. It is characterized by that.

  According to the seventh aspect of the invention, the inorganic fine particles are easily and uniformly dispersed even when a large amount of the cyclic polyolefin resin is mixed with the inorganic fine particle dispersed composition. Light transmittance and linear expansion coefficient can be maintained.

  An optical element according to an eighth aspect of the invention is characterized by being molded using the thermoplastic resin composition according to the seventh aspect.

  According to the invention described in claim 8, it is possible to improve the temperature dependency of the transparency and the refractive index of the molded optical element.

  According to the present invention, a large amount of inorganic fine particles can be easily and uniformly dispersed in an olefin resin having no polar group, and the transparency and refractive index of the obtained thermoplastic resin composition and optical element can be improved. The temperature dependency can be improved.

  The best mode for carrying out the present invention will be described below with reference to the drawings. However, although various technically preferable limitations for implementing the present invention are given to the embodiments described below, the scope of the invention is not limited to the following embodiments and illustrated examples.

First, the thermoplastic resin composition will be described.
The thermoplastic resin composition in the present embodiment includes an inorganic fine particle dispersion composition that is a mixture of at least one of an olefin resin and a resin additive, and inorganic fine particles and a surface treatment agent, and the inorganic fine particle dispersion composition. A thermoplastic resin.
Here, the details of the inorganic fine particle dispersion composition and the thermoplastic resin will be described below.

First, the thermoplastic resin will be described.
As the thermoplastic resin in the present embodiment, an olefin resin is used, and a cyclic polyolefin resin is particularly preferably used, but is not limited thereto. Two or more compatible resins may be used as these resins.
Specific examples include the compounds described in JP-A-2003-73559 and the like, and preferred compounds are shown in Table 1 below.

  When used as an optical material, the moisture absorption is preferably 0.2% or less from the viewpoint of dimensional stability. Therefore, polyolefin resin (polyethylene, polypropylene, etc.), fluororesin (polytetrafluoroethylene, manufactured by DuPont: Teflon) (Registered trademark) AF, manufactured by Asahi Glass: Cytop, cyclic polyolefin resin (manufactured by ZEON: ZEONEX, manufactured by Mitsui Chemicals: APEL, manufactured by JSR: Arton, manufactured by Ticona: TOPAS), indene / styrene-based resin, polycarbonate and the like are preferable. Used for.

Moreover, you may use together other resin compatible with these thermoplastic resins.
Here, the compatibility in the present embodiment refers to a completely compatible state that is soluble in a molecular state at an arbitrary ratio and a partially compatible state that is compatible under an arbitrary composition and temperature.

  Furthermore, when compatibilizing two or more components, the resin after compatibilization is the average of the physical and chemical properties of each component, or has physical and chemical properties that indicate the best properties of both. For example, when two or more kinds of resins are used, the water absorption is considered to be substantially the same as the average value of the water absorption in each resin, and the average water absorption should be 0.2% or less. .

Next, the olefin resin in the inorganic fine particle dispersion composition will be described.
The olefin resin in the present embodiment may be the above-described thermoplastic resin, but an olefin resin having a polar group is preferable from the viewpoint of interaction with the filler and the surface treatment agent. Specific examples of the polar group include a carboxyl group, an epoxy group, an amino group, and a hydroxyl group. These olefinic resins having a polar group may have two or more types of polar groups, and a mixture of an olefinic resin having two or more types of polar groups and an olefinic resin having no polar groups. It may be.

  Moreover, the compounding quantity of an olefin resin exists in the range of 0.1-20 weight part with respect to 100 weight part of polymers. This is because when the blending amount of the olefin resin is 0.1 parts by weight or less, the particle dispersion effect or the like is not exhibited, and when it is 20 parts by weight or more, it is inorganic when finally mixed in the olefin resin. This is because the filling rate of the fine particles may be reduced and the desired effect may not be exhibited.

In addition, when the olefin resin described above is used as an optical application, compatibility with the olefin resin that is a host material is required from the viewpoint of transparency, and therefore a polar group is introduced into the host material by an arbitrary method. Olefin resins are also preferably used.
As a method for producing an olefin resin having a polar group, known techniques such as a method of copolymerizing an unsaturated monomer having a polar group with an olefin resin can be applied.

Next, the resin additive will be described.
As the resin additive in the present embodiment, various types of resin additives may be used alone or in combination. Additives in this embodiment include whitening agents, heat stabilizers, antioxidants, light stabilizers, plasticizers, colorants, impact resistance improvers, extenders, antistatic agents, mold release agents, foaming agents, Examples include various substances such as processing aids.
Moreover, the range can be used suitably in the range which does not impair the effect as described in invention.
The resin additive in the present embodiment is intended to have an effect of dispersing inorganic fine particles at the time of creating the master batch and a binder function by being added to the master batch. These resin additives are appropriately selected and used within a range that can be compatibilized with each material used.

The compounding amount of the resin additive is in the range of 0.1 to 10 parts by weight and preferably in the range of 1 to 5 parts by weight with respect to 100 parts by weight of the polymer. This is because if the blending amount is too small, the dispersion effect of the inorganic fine particles is not sufficiently exerted at the time of preparing the inorganic fine particle dispersion composition, so that high filling becomes difficult, and if the blending amount is too large, the compatibility with the resin is maintained. This is because the transparency of the lens decreases.
In addition, the resin additive may be added at any timing including when the master batch is created.

In the following, specific examples of main resin additives among the various resin additives described above will be given, but the present invention is not particularly limited thereto.
Moreover, let the compounding quantity of the resin additive mentioned above be the total amount of the following various additives.

  The plasticizer in the present embodiment is not particularly limited, but is a phosphate ester plasticizer, a phthalate ester plasticizer, a trimellitic ester plasticizer, a pyromellitic acid plasticizer, a glycolate series. Examples thereof include a plasticizer, a citrate ester plasticizer, and a polyester plasticizer.

  In the phosphate ester plasticizer, for example, triphenyl phosphate, tricresyl phosphate, cresyl diphenyl phosphate, octyl diphenyl phosphate, diphenyl biphenyl phosphate, trioctyl phosphate, tributyl phosphate, etc., in the phthalate ester plasticizer, for example , Diethyl phthalate, dimethoxyethyl phthalate, dimethyl phthalate, dioctyl phthalate, dibutyl phthalate, di-2-ethylhexyl phthalate, butyl benzyl phthalate, diphenyl phthalate, dicyclohexyl phthalate, and the like. For trimellitic plasticizers, for example, tributyl trimellitate , Triphenyl trimellitate, triethyl trimellitate, etc., pyromellitic acid ester plasticizer, Examples of glycolate plasticizers include trabutyl pyromellitate, tetraphenyl pyromellitate, tetraethyl pyromellitate, and the like. For example, triacetin, tributyrin, ethyl phthalyl ethyl glycolate, methyl phthalyl ethyl glycolate, butyl phthalyl butyl For example, triethyl citrate, tri-n-butyl citrate, acetyl triethyl citrate, acetyl tri-n-butyl citrate, acetyl tri-n- (2-ethylhexyl) can be used as the citrate plasticizer. ) Citrate and the like.

  The resin additive in the present embodiment preferably contains a plasticizer such as fatty acid amide or fatty acid ester from the viewpoint of heat resistance and dispersibility of inorganic fine particles.

Examples of the antioxidant in the present embodiment include phenolic antioxidants, phosphorus antioxidants, sulfur antioxidants, and the like. Among these, phenolic antioxidants, particularly alkyl-substituted phenolic antioxidants are used. preferable. By blending these antioxidants, it is possible to prevent the lens from being colored or the strength from being reduced due to oxidative degradation during molding without reducing transparency, heat resistance and the like.
In addition, the antioxidants can be used alone or in combination of two or more kinds of antioxidants, and the blending amount thereof is appropriately selected within a range not impairing the object of the present invention. It is preferably in the range of 0.001 to 5 parts by weight, more preferably in the range of 0.01 to 1 part by weight with respect to parts by weight.

  As the phenol-based antioxidant, conventionally known ones can be applied, and 2-t-butyl-6- (3-t-butyl-2-hydroxy-5- 5 described in JP-A No. 63-179953. Methylbenzyl) -4-methylphenyl acrylate, 2,4-di-t-amyl-6- (1- (3,5-di-t-amyl-2-hydroxyphenyl) ethyl) phenyl acrylate, etc. Acrylate compounds described in Japanese Patent No. 1-186443; octadecyl-3- (3,5-di-t-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- (3,5-di- -Butyl-4-hydroxyphenyl) propionate], thiodiethylenebis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], 1,3,5-trimethyl-2,4,6- Alkyl-substituted phenols such as tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene and triethylene glycol bis (3- (3-t-butyl-4-hydroxy-5-methylphenyl) propionate) Compound; 6- (4-hydroxy-3,5-di-t-butylanilino) -2,4-bisoctylthio-1,3,5-triazine, 4-bisoctylthio-1,3,5-triazine, Triazine group-containing phenols such as 2-octylthio-4,6-bis- (3,5-di-t-butyl-4-oxyanilino) -1,3,5-triazine System compound; and the like.

  Phosphorus antioxidants include triphenyl phosphite, diphenylisodecyl phosphite, phenyl diisodecyl phosphite, tris (nonylphenyl) phosphite, tris (dinonylphenyl) phosphite, tris (2,4-di-t -Butylphenyl) phosphite, tris- (2,6-dimethylphenyl) phosphite, 10- (3,5-di-t-butyl-4-hydroxybenzyl) -9,10-dihydro-9-oxa-10 Monophosphite compounds such as phosphaphenanthrene-10-oxide; 4,4′-butylidene-bis (3-methyl-6-tert-butylphenyl-di-tridecyl phosphite), 4,4′-isopropyl Diphosphites such as redene-bis (phenyl-di-alkyl (C12-C15) phosphite) System compounds. 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.

  Sulfur antioxidants 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 and the like. .

Examples of the light resistance stabilizer in the present embodiment include a benzophenone light resistance stabilizer, a benzotriazole light resistance stabilizer, a hindered amine light resistance stabilizer, and the like. Therefore, it is preferable to use a hindered amine light stabilizer. Among hindered amine light-resistant stabilizers (hereinafter referred to as HALS: Hindered Amine Light Stabilizer), the number average molecular weight in terms of polystyrene (hereinafter referred to as Mn) measured by GPC (Gel Permeation Chromatography) using tetrahydrofuran (THF) as a solvent. : Number-average Molecular weight) is preferably in the range of 1000 to 10000, more preferably in the range of 2000 to 5000, and particularly preferably in the range of 2800 to 3800. This is because if Mn is too small, it becomes difficult to mix a predetermined amount due to volatilization when HALS is blended by heating and kneading into a block copolymer, and foaming is performed at the time of heat melting molding such as injection molding. This is because the processing stability is lowered, such as the occurrence of silver streaks. Further, when the lens is used for a long time with the lamp turned on, a volatile component is generated as a gas from the lens. On the contrary, if Mn is too large, the dispersibility in the block copolymer is lowered, the transparency of the lens is lowered, and the effect of improving the light resistance is reduced.
Therefore, in the present invention, a lens excellent in processing stability, low gas generation property, and transparency can be obtained by setting the MLS of HALS within the above-described range.

  Specific examples of such HALS include N, N ′, N ″, N ′ ″-tetrakis- [4,6-bis- {butyl- (N-methy-2,2,6,6-tetra Methylpiperidin-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 A polycondensate of hexanediamine-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] or the like, and high molecular weight HALS in which a plurality of piperidine rings are bonded via a triazine skeleton, dimethyl succinate and 4-hydroxy-2,2,6,6-tetramethyl-1-piperidine Polymer with ethanol, 1,2,3,4-butanetetracarboxylic acid, 1,2,2,6,6-pentamethyl-4-piperidinol and 3,9-bis (2-hydroxy-1,1-dimethyl) As such mixed ester of chill) -2,4,8,10-spiro [5,5] undecane, piperidine ring linked to a high molecular weight HALS, and the like via an ester bond.

  Among the HALS mentioned above, a polycondensation product 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, etc. In addition, it is preferable that Mn is in the range of 2000 to 5000.

Next, inorganic fine particles will be described.
The inorganic fine particles in the present embodiment preferably have an average particle size in the range of 1 nm to 30 nm, more preferably in the range of 1 nm to 20 nm, and in the range of 1 nm to 10 nm. Particularly preferred. When the average particle diameter is less than 1 nm, it is difficult to disperse the inorganic fine particles and the desired performance may not be obtained. Therefore, the average particle diameter is preferably 1 nm or more, and the average particle diameter is preferably 30 nm. If it exceeds the upper limit, the resulting thermoplastic material composition may become turbid, resulting in a decrease in transparency, and the light transmittance may be less than 70%. Therefore, the average particle diameter is preferably 30 nm or less.
Here, the average particle diameter means a diameter when converted to a sphere having the same volume as the particles.

The shape of the inorganic fine particles is not particularly limited, but spherical inorganic fine particles are preferably used. This is because when the inorganic fine particles are spherical, it is possible to prevent thickening during the kneading of the inorganic fine particles.
Further, the particle size distribution of the inorganic fine particles is not particularly limited, but inorganic fine particles having a relatively narrow distribution are preferably used in order to efficiently express the intended effect.

  Examples of the inorganic fine particles include oxide fine particles, sulfide fine particles, selenide fine particles, telluride fine particles, phosphides, double oxide fine particles, oxo acid salt fine particles, double salt fine particles, complex salt fine particles, and the like. More specifically, 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. that are composed of these oxides, phosphates, sulfates, etc. formed in combination with these oxides, Examples thereof include, but are not limited to, zinc sulfide, cadmium sulfide, zinc selenide, cadmium selenide, and the like.

As the inorganic fine particles, fine particles having a semiconductor crystal composition can be suitably used. The semiconductor crystal composition is not particularly limited, but a semiconductor crystal composition that does not absorb, emit light, or fluoresce in a wavelength region used as an optical element is preferable. Specific examples of the composition include simple elements of Group 14 elements of the periodic table such as carbon, silicon, germanium and tin, simple elements of Group 15 elements of the periodic table such as phosphorus (black phosphorus), and periodic tables such as selenium or tellurium. A group 16 element simple substance, a compound composed of a plurality of Group 14 elements of the periodic table 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 (II) sulfide (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), 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 (or III-V compound semiconductors) such as indium (InP), indium arsenide (InAs), indium antimonide (InSb), aluminum sulfide (Al ₂ S ₃ ), aluminum selenide (Al ₂ Se ₃ ), gallium sulfide (Ga ₂ S ₃ ), gallium selenide (Ga ₂ Se ₃ ), gallium telluride (Ga ₂ Te ₃ ), indium oxide (In ₂ O ₃₎ ), indium sulfide _{(In 2 S} 3), indium selenide _{(an In} 2 Se ), Compounds of tellurium indium _(In 2 Te ₃₎ periodic table group 13 elements and the periodic table group 16 element such as, thallium chloride (I) (TlCl), thallium bromide (I) (TlBr), iodine Compounds of periodic table group 13 elements and periodic table group 17 elements such as thallium (I) fluoride (TlI), zinc oxide (ZnO), zinc sulfide (ZnS), zinc selenide (ZnSe), zinc telluride ( ZnTe), cadmium oxide (CdO), cadmium sulfide (CdS), cadmium selenide (CdSe), cadmium telluride (CdTe), mercury sulfide (HgS), mercury selenide (HgSe), mercury telluride (HgTe), etc. Compound (or II-VI group compound semiconductor) of periodic table group 12 element and periodic table group 16 element, 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 ), antimony selenide (III) (Sb ₂ Se ₃ ), antimony telluride (III) (Sb) ₂ Te ₃ ), Bismuth sulfide (III) (Bi ₂ S ₃ ), Bismuth selenide (III) (Bi ₂ Se ₃ ), Bismuth telluride (III) (Bi ₂ Te ₃ ) group 15 elements of the periodic table And a group 16 element of the periodic table, a group 11 element of the periodic table such as copper (I) (Cu ₂ O), copper selenide (Cu ₂ Se), and a group 16 element of the periodic table Group 11 of the periodic table of compounds, copper (I) chloride (CuCl), copper bromide (I) (CuBr), copper iodide (I) (CuI), silver chloride (AgCl), silver bromide (AgBr), etc. Compounds of elements and group 17 elements of the periodic table, such as nickel oxide (II) (NiO) Compounds of Periodic Table Group 10 and Periodic Table Group 16 Elements, Periodic Table Group 9 Elements and Periodic Table Group 16 Elements such as Cobalt (II) Oxide (CoO), Cobalt Sulfide (II) (CoS) Compounds of the periodic table group 8 elements such as triiron tetroxide (Fe ₃ O ₄ ), iron sulfide (II) (FeS), etc., compounds of group 16 elements of the periodic table, manganese (II) (MnO), etc. A periodic table group 6 element and a periodic table group 16 element, molybdenum sulfide (IV) (MoS ₂ ), tungsten oxide (IV) (WO ₂ ), etc. Compounds with Group elements, Periodic Table Group 5 elements and Periodic Table Group 16 such as vanadium (II) oxide (VO), vanadium oxide (IV) (VO ₂ ), tantalum oxide (V) (Ta ₂ O ₅ ), etc. the compounds of the elements titanium oxide _{(TiO 2, Ti 2 O 5} , Ti 2 O 3, Ti O _9, etc.) of the periodic table compounds of the fourth group element and Periodic Table Group 16 element such as, magnesium sulfide (MgS), Group 2 elements and Periodic Table Group 16 element such as magnesium selenide (MgSe) , Cadmium (II) chromium (III) (CdCr ₂ O ₄ ), cadmium selenide (II) chromium (III) (CdCr ₂ Se ₄ ), copper sulfide (II) chromium (III) (CuCr ₂ S) ₄ ), chalcogen spinels such as mercury (II) selenide (II) and chromium (III) (HgCr ₂ Se ₄ ), barium titanate (BaTiO ₃ ) and the like.

In addition, G. Schmid et al., Adv. Mater. (BN) ₇₅ (BF ₂ ) ₁₅ F ₁₅ described in 1991, Vol. 4, p. Fenske et al., Angew. Chem. Int. Ed. Engl. , 1990, Vol. 29, p.1452, a semiconductor cluster having a fixed structure such as Cu ₁₄₆ Se ₇₃ (triethylphosphine) ₂₂ described in the same manner is also exemplified.

As the inorganic fine particles described above, one kind of inorganic fine particles may be used, or a plurality of kinds of inorganic fine particles may be used in combination. It is also possible to use inorganic fine particles having a composite composition.
The inorganic fine particle dispersion composition in the present embodiment is intended to finally obtain a desired thermoplastic resin composition by mixing with a thermoplastic resin. The fine particle concentration is higher than the inorganic fine particle concentration in the thermoplastic resin composition as the final product. This is because in order to obtain a desired thermoplastic resin composition by mixing with a thermoplastic resin, a certain level of inorganic fine particle concentration is required. More specifically, the inorganic fine particle dispersion composition contains inorganic particles. The volume fraction of the fine particles is preferably 10% or more.

  Further, the volume ratio of the inorganic fine particles contained in the thermoplastic resin composition is preferably in the range of 1 to 70 vol%, more preferably in the range of 10 to 50 vol%. This is because when the content of the inorganic fine particles in the thermoplastic resin composition is 1 vol% or less, the desired physical properties may not be improved. Further, when the content of the inorganic fine particles is 70 vol% or more, there is a problem in economic efficiency and moldability.

  The method for producing the inorganic fine particles is not particularly limited, and any known method can be used. Hydrolysis is performed in a reaction system containing water using a metal halide or an alkoxy metal as a raw material. By doing so, desired oxide fine particles can be obtained. 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. As a specific example, in the case of titanium dioxide fine particles, Journal of chemical engineering of Japan, 1998, Vol. 1, No. 1, p. 21-28, in the case of zinc sulfide, Journal of physical chemistry, 1996. It is possible to use a known method described in the year, volume 100, pages 468-471.

Titanium oxide having an average particle diameter of 5 nm can be easily obtained by adding an appropriate surface modifier when hydrolyzed in an appropriate solvent using titanium tetraisopropoxide or titanium tetrachloride as a raw material. Can be created.
Zinc sulfide having an average particle diameter of 40 nm can be prepared by adding a surface modifier when sulfiding with dimethyl zinc or zinc chloride as a raw material with hydrogen sulfide or sodium sulfide.

  The surface modification method of the inorganic fine particles thus produced is not particularly limited, and any conventionally known method can be applied. For example, a method of modifying the surface of the inorganic fine particles by hydrolysis under conditions where water is present can be mentioned. In this method, an acid or alkali catalyst is preferably used, and it is considered that a hydroxyl group on the surface of the inorganic fine particle and a hydroxyl group generated by hydrolysis of the surface modifier are dehydrated to form a bond. Yes.

  In addition to the production of inorganic fine particles from the cluster as described above by a bottom-up process, a top-down process for producing fine particles by pulverizing inorganic fine particles has also been proposed. As the pulverizer used in the top-down process, Ultra Apex Mill (manufactured by Kotobuki Giken); Counter Jet Mill, Micron Jet, Inomizer (manufactured by Hosokawa Micron); IDS type mill, PJM Jet Crusher (manufactured by Nippon Pneumatic Industry); Cross jet mill (manufactured by Kurimoto Iron Works); Urmax (manufactured by Nisso Engineering); SK Jet Oh Mill (manufactured by Seishin Enterprise); Kryptron (manufactured by Kawasaki Heavy Industries); Turbo mill (manufactured by Turbo Industry); Sei Engineering Co., Ltd.).

The inorganic fine particles prepared by such a method are subjected to a surface treatment with a coupling agent such as a silane, silicone oil, titanate, aluminate or zirconate which is a surface treatment agent.
These coupling agents are appropriately selected according to the type of inorganic fine particles used. Moreover, when performing 2 or more types of surface treatments, various surface treatments may be performed simultaneously or at different times.

  As the silane coupling agent, conventionally known ones such as vinylsilazane trimethylchlorosilane, dimethyldichlorosilane, methyltrichlorosilane, trimethylalkoxysilane, dimethyldialkoxysilane, methyltrialkoxysilane, and hexamethyldisilazane may be used. Although possible, hexamethyldisilazane or the like is preferably used in order to cover the surface of the fine particles over a wide range.

Examples of silicone oil coupling agents 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, carbinol-modified silicone oil, Methacryl-modified silicone oil, mercapto-modified silicone oil, phenol-modified silicone oil, one-end reactive modified silicone oil, heterogeneous 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 oil It can be used higher fatty acid containing modified silicone oil, a modified silicone oil such as fluorine-modified silicone oil.
Further, these treatment agents may be appropriately diluted with hexane, toluene, methanol, ethanol, acetone water, or the like.

  Examples of the surface modification method using the coupling agent described above include a wet heating method, a wet filtration method, a dry stirring method, an integral blend method, a granulation method, and the like. The inorganic fine particles may be subjected to a surface treatment in advance.

  The addition amount of the coupling agent is relatively large in consideration of the large specific surface area and the problem of reactivity during kneading into the thermoplastic resin because the inorganic fine particles are nano-order. In view of the increase in the linear expansion coefficient due to the generation of minute spaces in the thermoplastic resin composition and the decrease in light transmittance due to the occurrence of aggregation of the inorganic fine particles, the amount is at least 5 parts by weight relative to 100 parts by weight of the inorganic fine particles In consideration of an increase in manufacturing cost and an increase in viscosity, the amount is 20 parts by weight or less with respect to 100 parts by weight of the inorganic fine particles.

In addition, when mixing the olefin resin or resin additive, the inorganic fine particles, and the surface treatment agent described above, they can be uniformly mixed by using a solvent.
The solvent in the present embodiment is not particularly limited as long as the olefin resin, the resin additive, and the surface treatment agent are dissolved. For example, aromatic hydrocarbons such as benzene, toluene, xylene, Esters such as acetone, methyl ethyl ketone, cyclohexanone, heptanone, 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, Ethers such as 1,3-dioxane and 1,4-dioxane, N, N-dimethylformamide, N, N-dimethylacetamide, dimethyl sulfoxide, N-methyl-2-pyrrolidine, Aprotic polar solvents such as Holland. These solvents can be used alone or in combination.

  The boiling point of the solvent in the present embodiment at atmospheric pressure is preferably in the range of 30 to 200 ° C, and more preferably in the range of 50 to 100 ° C. This is because a boiling point lower than 30 ° C. is dangerous in handling. On the other hand, when the boiling point is higher than 100 ° C., it is difficult to remove the solvent and adversely affect the thermoplastic resin composition, which is the final product, due to residual decomposition products and the influence of heating.

  As a method for preparing the mixture of the olefin resin, the resin additive, the inorganic fine particles, and the surface treatment agent described above, that is, the inorganic fine particle dispersion composition, in addition to the method of stirring and mixing in the solvent described above, a kneading apparatus, Examples thereof include a mixing method using a conventionally known dispersing device and mixing device such as a granulating device.

  In the case of a method of stirring and mixing in a solvent, the volatile residue such as a solvent is 2% or less of the total volume from the viewpoint of adverse effects on the thermoplastic resin composition as the final product and economy. Is preferred.

Next, the manufacturing method of the thermoplastic resin composition in this embodiment is demonstrated.
In order to obtain a composition in which inorganic fine particles are highly dispersed, the method for producing a thermoplastic resin composition in the present embodiment is performed by a melt-kneading apparatus while mixing the inorganic fine particle dispersed composition and the thermoplastic resin in a solvent. It is manufactured by applying a shearing force and carrying out dispersion and surface modification.

  Moreover, the content rate of the inorganic fine particle dispersion composition in the thermoplastic resin composition which is the final product is usually in the range of 5 to 50%. This is because when the content of the inorganic fine particles is very small, the desired physical property improving effect by the inorganic fine particles is impaired. On the other hand, when the content is very large, the resin deteriorates as a result of spending a lot of time to perform uniform mixing in the kneading apparatus, and the inorganic fine particle dispersion composition adheres to the inner wall surface of the kneading apparatus. Because it will end up.

  The mixing of the inorganic fine particle dispersion composition and the thermoplastic resin described above is preferably performed in an atmosphere substituted with argon gas, nitrogen gas, or the like in order to prevent functional deterioration due to oxidation.

  Examples of the kneading apparatus used for melt kneading include a single screw extruder, a twin screw extruder, a roll, a Banbury mixer, a kneader, and the like, and a kneading apparatus with high shear efficiency is particularly preferable. Specific kneaders include KRC kneader (manufactured by Kurimoto Iron Works), polylab system (manufactured by HAAKE), nanocon mixer (manufactured by Toyo Seiki Seisakusho), Nauter mixer bus co-kneader (manufactured by Buss), TEM Extruder (made by Toshiba Machine), TEX twin-screw kneader (made by Nippon Steel), PCM kneader (made by Ikegai Iron Works), three roll mill, mixing roll mill, kneader (made by Inoue Seisakusho), needex (Mitsui Mine) Product), MS pressure kneader, nider ruder (manufactured by Moriyama Seisakusho), Banbury mixer (manufactured by Kobe Steel), and the like.

  In addition, when the degree of mixing is insufficient, there is a risk of affecting the resin processability such as thermoplasticity and melt moldability, and in particular, the light transmittance may be affected. Thus, it is considered that the degree of mixing is affected by the preparation method, and it is necessary to select an optimal method in consideration of the characteristics of the thermoplastic resin and inorganic fine particles used.

  Various molding materials can be obtained by molding the thermoplastic resin composition prepared by the above method. The molding method is not particularly limited, but melt molding is particularly preferable in order to obtain a molded product excellent in characteristics such as low birefringence, mechanical strength and dimensional accuracy. Examples of the melt molding method include commercially available press molding, commercially available extrusion molding, and commercially available injection molding. From the viewpoint of moldability and productivity, injection molding is preferred.

  The molding conditions in the molding process are appropriately selected depending on the purpose of use or the molding method. The temperature of the resin composition in the injection molding is such that an appropriate fluidity is imparted to the resin at the time of molding to prevent sink marks and distortion of the molded product. From the viewpoint of preventing the occurrence of silver streak due to thermal decomposition of the resin, and effectively preventing yellowing of the molded product, it is preferably in the range of 150 ° C to 400 ° C, and 200 ° C to 350 ° C. More preferably, it is in the range of 200C, particularly preferably in the range of 200C to 330C.

The molded product 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 or a sheet shape, and has a low birefringence and transparency. Because of its excellent properties, mechanical strength, heat resistance, and low water absorption, it can be applied to various optical components.
As a specific application example, as an optical lens or an optical prism, an imaging lens of a camera; a lens such as a microscope, an endoscope or a telescope lens; an all-light transmission lens such as a spectacle lens; a CD or a CD-ROM , WORM (recordable optical disc), MO (rewritable optical disc; magneto-optical disc), MD (mini disc), DVD (digital video disc) and other optical disc pickup lens; laser beam printer fθ lens, sensor lens And a laser scanning system lens such as a camera finder system prism lens.
Other optical applications include light guide plates such as liquid crystal displays; optical films such as polarizing films, retardation films, and light diffusion films; light diffusion plates; optical cards; and liquid crystal display element substrates.

  Among the above-described molded products, the thermoplastic resin composition of the present embodiment is suitably used as an optical element such as a pickup lens that requires low birefringence and a laser scanning system lens. An optical pickup device 1 using an optical element formed by an object will be described.

  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 which is an optical element 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, DVD20 or CD30. It is supposed to concentrate on. 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 recording medium, details of the 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 splitter BS5, and the collimator CL, is reflected by the splitter BS1, and then passes through the cylindrical lens L11 to give astigmatism. Thereafter, the 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, the 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, the 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.

  Note that the optical pickup device 1 has spot spots at the photodetectors 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.

Next, examples of the thermoplastic resin composition according to the present invention will be described.
[Example 1]
10 g of cyclic olefin resin (manufactured by Nippon Zeon: ZEONEX 330R), 100 g of alumina (manufactured by Daimei Chemical Co., Ltd .: TM-300, primary particle size 7 nm), 10 g of coupling agent (manufactured by Toray Dow Corning: SZ-6187), amide-based lubricant 5 g (manufactured by NOF Corporation: WA-1) was dissolved in 200 ml of a cyclohexane solution, mixed and stirred, and then dried at a temperature of 80 ° C. to obtain an inorganic fine particle dispersion composition. Thereafter, the inorganic fine particle dispersion composition and the cyclic polyolefin resin (manufactured by Nippon Zeon: ZEONEX 330R) are adjusted to a ratio such that the inorganic fine particles become 20 vol%, and using a twin-screw kneading extruder (manufactured by Nippon Steel: TEX). A thermoplastic resin composition was prepared by kneading at a temperature of 190 ° C. Then, the optical element 1 was created by injection molding.

[Example 2]
100 g of alumina (manufactured by Nippon Aerosil Co., Ltd .: Alumina C, primary particle size 12 nm), 10 g of coupling agent (manufactured by Toray Dow Corning: SZ-6187), and 5 g of amide-based lubricant (manufactured by Nippon Oil & Fats: WA-1) It was dissolved in 200 ml of the solution, mixed and stirred, and then dried at a temperature of 80 ° C. to obtain an inorganic fine particle dispersion composition. Thereafter, the inorganic fine particle dispersion composition and the cyclic polyolefin resin (manufactured by Nippon Zeon: ZEONEX 330R) are adjusted to a ratio such that the inorganic fine particles become 20 vol%, and using a twin-screw kneading extruder (manufactured by Nippon Steel: TEX). A thermoplastic resin composition was prepared by kneading at a temperature of 190 ° C. Then, the optical element 2 was created by injection molding.

[Example 3]
In 400 ml of cyclohexane solution, 100 g of silica (manufactured by Nippon Aerosil Co., Ltd .: A-300, primary particle size 7 nm), 10 g of coupling agent (manufactured by Shin-Etsu Silicone: HMDS), and 10 g of modified olefin resin (manufactured by Ticona: Topas TMG2050) Then, the mixture was stirred and dried at a temperature of 80 ° C. to obtain a master batch. Thereafter, the master batch and the cyclic polyolefin resin (manufactured by Mitsui Chemicals: APEL5014) are adjusted to a ratio such that the inorganic fine particles become 20 vol%, and a biaxial kneading extrusion apparatus (manufactured by Nippon Steel Co., Ltd .: TEX) is used. Kneading was performed at a temperature of 0 ° C. to prepare a thermoplastic resin composition. Then, the optical element 3 was created by injection molding.

[Comparative Example 1]
In Example 1, the optical element 4 was produced by the same method except not using a silane coupling agent.

[Comparative Example 2]
In Example 2, an optical element 5 was produced in the same manner except that no amide lubricant was used.

[Comparative Example 3]
In Example 1, the silane coupling agent was not added to the inorganic fine particle dispersion composition, but was dropped while being kneaded at a temperature of 190 ° C. using a twin-screw kneading extruder (manufactured by Nippon Steel Co., Ltd .: TEX). Other than that, the optical element 6 was produced by the same method.

[Comparative Example 4]
The mass of the amide-based lubricant (made by NOF Corporation: WA-1) in Example 1 was changed from 5 g to 0.05 g, and the type of inorganic fine particles used was changed to alumina (Daimei Chemical Co., Ltd .: TM-300, primary). Optical element 7 was produced in the same manner except that the particle size was changed from 7 nm to 100 g of silica (manufactured by Nippon Aerosil Co., Ltd .: A-200, primary particle size 12 nm).

[Comparative Example 5]
The mass of the amide-based lubricant (manufactured by NOF: WA-1) in Example 1 was changed from 0.05 g to 20 g, and the type of inorganic fine particles used was changed to alumina (Daimei Chemical Co., Ltd .: TM-300, primary). Optical element 8 was produced by the same method except that the particle size was changed from 7 nm to 100 g of silica (manufactured by Nippon Aerosil Co., Ltd .: A-300, primary particle size 7 nm).

[Comparative Example 6]
The mass of 10 g of the coupling agent (Toray Dow Corning Co., Ltd .: SZ-6187) in Example 1 was changed from 10 g to 1 g, and the type of inorganic fine particles used was alumina (Daimei Chemical Co., Ltd .: TM-300, 1 The optical element 9 was produced in the same manner except that the silica particle (made by Nippon Aerosil Co., Ltd .: A-200, primary particle size 12 nm) was changed to 100 g from the secondary particle size 7 nm.

[Comparative Example 7]
The mass of the amide-based lubricant (made by NOF Corporation: WA-1) in Example 1 was changed from 5 g to 25 g, and the kind of inorganic fine particles used was changed to alumina (Daimei Chemical Co., Ltd .: TM-300, primary particle size). The optical element 10 was produced by the same method except that 7 g was changed to 100 g of silica (manufactured by Nippon Aerosil Co., Ltd .: A-300, primary particle size 7 nm).

[Comparative Example 8]
Optical element 11 was produced in the same manner as in Example 1 except that the mass of the cyclic polyolefin resin in Example 1 (manufactured by ZEON Corporation: ZEONEX 330R) was changed from 10 g to 0.05 g.

[Comparative Example 9]
The cyclic polyolefin resin in Example 1 (manufactured by Nippon Zeon: ZEONEX 330R) was changed to an acid-modified olefin resin (manufactured by Ticona: Topas TMG2050), and the addition amount was changed from 10 g to 30 g, as in Example 1. The optical element 12 was produced by the same method.

Finally, an evaluation method for the thermoplastic resin composition will be described.
Evaluation items include a total of two items, light transmittance and linear expansion coefficient, and the details of the measurement method for each item will be described below.

First, a method for measuring light transmittance will be described.
Using a spectrophotometer (manufactured by Shimadzu Corporation: UV-3150), the transmittance at a wavelength of 587.5 nm in the thickness direction (3 mm thickness) of each of the optical elements 1 to 12 described above was measured. It is shown in Table 2.

Next, a method for measuring the linear expansion coefficient will be described.
The linear expansion coefficients of the optical elements 1 to 12 described above were measured by a thermomechanical analysis method (TMA: Thermo Mechanical Analysis) using a thermal analyzer (manufactured by Rigaku: CN8098F1). In addition, after performing the annealing process for 1 hour at the preset temperature of 90 degreeC before a measurement, the linear expansion coefficient in 40-60 degreeC was measured, and the obtained result was shown in following Table 2.

  As a result, optical elements 1, 2, and 3 in which at least one of an olefin resin and a resin additive, an inorganic fine particle, and a surface modifier are contained in the inorganic fine particle dispersion composition, the olefin is added to the inorganic fine particle dispersion composition. Optical element 4 containing no resin or resin additive, optical element 5 containing no surface modifier in the inorganic fine particle dispersion composition, or cyclic polyolefin instead of the inorganic fine particle dispersion composition. Compared with the optical element 6 added to the resin, the optical elements 1, 2 and 3 have higher light transmittance values and lower linear expansion coefficient values, that is, excellent transparency and temperature dependence of the refractive index. It was confirmed that the sex was suppressed.

  Moreover, the compounding quantity of the olefin resin contained in the inorganic fine particle dispersion composition is in the range of 0.1 to 20 parts by weight, and the compounding quantity of the olefin resin is 0.05 and 30 weights. Comparing with the optical elements 11 and 12, which are optical parts, the optical elements 1 and 3 have higher light transmittance values and lower linear expansion coefficient values, that is, excellent transparency and temperature dependency of the refractive index. Was confirmed to be suppressed.

  Furthermore, the optical elements 1 and 2 in which the compounding amount of the resin additive contained in the inorganic fine particle dispersion composition is in the range of 0.1 to 10 parts by weight, and the compounding amount of the resin additive is 0.05 and 20 wt. In comparison with the optical elements 7 and 8, which are optical parts, the optical elements 1 and 2 have higher light transmittance values and lower linear expansion coefficient values, that is, excellent transparency and temperature dependency of the refractive index. Was confirmed to be suppressed.

  Further, the optical element 1, 2, 3 in which the amount of the surface modifier contained in the inorganic fine particle dispersion composition is in the range of 5 to 20 parts by weight, and the amount of the surface modifier is 1 and 25 weights. In comparison with the optical elements 9 and 10 that are optical parts, the optical elements 1 and 2 have higher light transmittance values and lower linear expansion coefficient values, that is, excellent transparency and temperature dependency of the refractive index. Was confirmed to be suppressed.

As described above, according to the inorganic fine particle dispersion composition, the thermoplastic resin composition and the optical element in the present embodiment, since the resin additive as the binder is contained, the compatibility between the olefin resin and the inorganic fine particles is improved. By improving, the dispersibility of the inorganic fine particles during kneading can be improved, and the light transmittance can be improved.
In addition, at the time of preparing the inorganic fine particle dispersion composition, at least one of a silane coupling agent and a titanium coupling agent is added in advance, and orientation is performed with respect to the interface of the inorganic fine particles, whereby the surface treatment agent at the time of kneading is performed. It is possible to perform the uniform surface treatment for the inorganic fine particles.
For this reason, a large amount of the inorganic fine particle dispersion composition can be uniformly added to the olefin resin, and the light transmittance and the linear expansion coefficient in the obtained thermoplastic resin composition can be improved. In addition, an optical element excellent in temperature dependency of the refractive index can be manufactured.

It is the schematic which shows the structure of the optical pick-up apparatus using the optical element which concerns on this invention.

Explanation of symbols

15 Objective lens

Claims (8)

  Inorganic containing at least one of 0.1 to 20 parts by weight of olefin resin and 0.1 to 10 parts by weight of resin additive, 100 parts by weight of inorganic fine particles, and 5 to 20 parts by weight of a surface treatment agent Fine particle dispersion composition.   The inorganic fine particle dispersion composition according to claim 1, wherein the olefin resin has a polar group and is compatible with a thermoplastic resin to be mixed.   2. The inorganic fine particle dispersion composition according to claim 1, wherein the resin additive contains at least one of a fatty acid amide and a fatty acid ester.   The inorganic fine particle dispersion composition according to claim 1, wherein the inorganic fine particles have an average particle size of 30 nm or less.   2. The inorganic fine particle dispersion composition according to claim 1, wherein the surface treatment agent is at least one of a silane coupling agent and a titanium coupling agent.   2. The method according to claim 1, wherein at least one of the olefinic resin and the resin additive, the inorganic fine particles, and the surface treatment agent are uniformly mixed in a solvent and then dried. The inorganic fine particle dispersion composition according to any one of claims 5 to 6.   A thermoplastic resin composition produced by mixing the inorganic fine particle dispersion composition according to any one of claims 1 to 6 and a cyclic polyolefin resin.   An optical element formed by using the thermoplastic resin composition according to claim 7.

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