JP2007138041A - Thermoplastic composite material and optical element, and method for producing thermoplastic composite material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermoplastic composite material and an optical element capable of extremely minimizing changes in a refractive index due to temperature and a method for producing such thermoplastic composite material. <P>SOLUTION: The transparent thermoplastic composite material is produced by dispersing particulates having a mean particle diameter of 1 nm or more and 50 nm or less in a thermoplastic resin comprising an organic polymer, wherein the particulate is an amorphous inorganic fine particle containing aluminium. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a thermoplastic composite material and an optical element that are suitably used as a lens, a filter, a grating, an optical fiber, a flat optical waveguide, etc., and have a small temperature change rate of refractive index, and a method for producing a thermoplastic composite material.

  Information devices such as a player, a recorder, and a drive for reading and recording information on an optical information recording medium (hereinafter also simply referred to as a medium) such as MO, CD, and DVD are provided with an optical pickup device. The optical pickup device includes an optical element unit that irradiates a medium with light having a predetermined wavelength emitted from a light source, and receives the reflected light with a light receiving element. The optical element unit receives the light from a reflection layer or a light receiving medium of the medium. An optical element such as a lens for condensing light by the element is included.

  The optical element of the optical pickup device is preferably made of plastic as a material in that it can be manufactured at low cost by means such as injection molding. As a plastic applicable to an optical element, a cyclic olefin and a thermoplastic composite material-olefin copolymer (for example, see Patent Document 1) is known.

  By the way, in the case of an information device capable of reading and writing information on a plurality of types of media such as a CD / DVD player, for example, the optical pickup device responds to differences in the shape of both media and the wavelength of light to be applied. It is necessary to make it the structure. In this case, it is preferable from the viewpoint of cost and pickup characteristics that the optical element unit is common to all the media.

On the other hand, an optical element unit using plastic as a material is required to be a substance having optical stability such as a glass lens. For example, optical plastic materials such as cyclic olefins have significantly improved refractive index stability with respect to humidity, whereas the improvement in refractive index stability with temperature is not yet sufficient. .
As one of methods for correcting the optical refractive index of the plastic lens as described above, various methods using a fine particle filler have been proposed.

  This fine particle filler is used to modify the refractive index of optical plastics, and by using a filler whose particle size is sufficiently small, no light scattering is caused by the filler. As a result, sufficient transparency can be maintained. For example, Non-Patent Document 1 and Non-Patent Document 2 describe technical documents describing the addition of fine particles for increasing the refractive index of plastics.

  Alternatively, a fine synthetic optical product composed of a polymer-like thermoplastic resin having temperature sensitivity and a dispersed fine particle substance and having reduced temperature sensitivity has been proposed (for example, Patent Documents 2 and 3). reference). In the patent document, for example, it is described that temperature sensitivity is reduced by mixing 40 mass% or more of crystalline fine particles of aluminum oxide or magnesium oxide in a thermoplastic resin. A resin material obtained by mixing a large amount of inorganic fine particles having a large difference in refractive index with a resin has a large decrease in light transmittance, and has only been able to provide a resin material that is not suitable for practical use as an optical element.

  In addition, a transparent resin composition in which silica fine particles having a diameter of a visible light wavelength (380 nm) or less are dispersed and mixed in a transparent amorphous organic polymer for the purpose of ensuring the strength or rigidity and transparency of the resin window. A resin window made of a material (see Patent Document 4). Or the resin composition (refer patent document 5) containing the thermoplastic compound and the oxidation compound which has a hydrophobic group and a polar group on the surface for the purpose of the improvement of rigidity and dimensional stability is disclosed.

On the other hand, as an amorphous structure containing aluminum, for example, an aluminum phosphate composition having pores (see Patent Document 6) and amorphous aluminum silicate particles having an average particle diameter of 0.5 to 5.0 μm (Patent Document) 7) is known.
JP 2002-105131 A JP 2002-207101 A Japanese Patent Application Laid-Open No. 2002-241592 Japanese Patent No. 3559894 JP 2004-269773 A JP-A-6-107403 Japanese Patent Laid-Open No. 5-17622 C. Becker, et al., "Optical and thermodynamic investigations in thermoplastic microsynthetic materials with surfaces modified with silica microparticles", SPIE Proceedings, 3469, July 1998, pages 88-98. B. Braune, et al., "Tantalum Oxide Nanomers for Optical Applications", SPIE Processings, 3469, July 1998, pages 124-132.

However, in the resin compositions of Patent Document 1 to Patent Document 5, amorphous silica particles such as crystalline fine particles or colloidal silica are used at the time of production, and the resin has a three-dimensional structure generated by a crosslinking reaction between the particles and the host resin material. Since the strength and rigidity of the composition are increased, the fluidity is low and there is a problem in moldability. In particular, if the volume fraction of the fine particles is increased, the fluidity is greatly reduced and the transparency is liable to decrease. Therefore, the resin composition obtained by these methods has sufficient light transmission for use as an optical element. Can't get rate.
Further, the aluminum phosphate composition of Patent Document 6 and the amorphous aluminum silicate particles of Patent Document 7 are insufficient to improve the optical characteristics.

  The present invention has been made in view of the above points, and is a thermoplastic composite material that is a resin composition capable of extremely reducing a change in refractive index with respect to temperature, an optical element using the same, and a thermoplastic composite material. It aims at providing the manufacturing method of.

In order to solve the above problems, the invention described in claim 1
A transparent thermoplastic composite material in which fine particles having an average particle diameter of 1 nm or more and 50 nm or less are dispersed in a thermoplastic resin made of an organic polymer, wherein the fine particles contain amorphous inorganic fine particles It is characterized by being.

Invention of Claim 2 is the thermoplastic composite material of Claim 1, Comprising:
The amorphous inorganic fine particles are formed in a liquid phase.

Invention of Claim 3 is the thermoplastic composite material of Claim 1 or Claim 2, Comprising:
The amorphous inorganic fine particles are amorphous aluminum phosphate fine particles having a molar ratio of phosphorus to aluminum of 0.9 to 1.1.

The invention according to claim 4 is the thermoplastic composite material according to claim 3,
The amorphous aluminum phosphate fine particles are formed by mixing an aluminum salt solution and a phosphate solution.

Invention of Claim 5 is the thermoplastic composite material of Claim 3, Comprising:
The amorphous aluminum phosphate fine particles are formed by mixing an aluminum nitrate aqueous solution and an ammonium phosphate aqueous solution.

Invention of Claim 6 is the thermoplastic composite material as described in any one of Claims 1-5, Comprising:
The amorphous inorganic fine particles are characterized in that the surface of the particles is modified with an organosilane compound.

Invention of Claim 7 is a thermoplastic composite material as described in any one of Claims 1-6, Comprising:
The volume fraction of the amorphous inorganic fine particles is 20% or more and 60% or less.

Invention of Claim 8 is a thermoplastic composite material as described in any one of Claims 1-7, Comprising:
The thermoplastic resin includes at least one of acrylic resin, cyclic olefin resin, polycarbonate resin, polyester resin, polyether resin, polyamide resin, and polyimide resin.

The invention according to claim 9 is an optical element,
It is shape | molded using the thermoplastic composite material as described in any one of Claims 1-8.

The invention according to claim 10 is a method for producing a transparent thermoplastic composite material,
The method comprises a step of dispersing fine particles having an average particle diameter of 1 nm or more and 50 nm or less in a thermoplastic resin made of an organic polymer, and the fine particles are formed using amorphous inorganic fine particles containing aluminum. It is characterized by that.

Invention of Claim 11 is a manufacturing method of the thermoplastic composite material of Claim 10, Comprising:
The amorphous inorganic fine particles include a step of forming in a liquid phase.

Invention of Claim 12 is a manufacturing method of the thermoplastic composite material of Claim 10 or Claim 11, Comprising:
The amorphous inorganic fine particles are amorphous aluminum phosphate fine particles, and the amorphous aluminum phosphate fine particles are formed through a step of mixing an aluminum salt solution and a phosphate solution. .

Invention of Claim 13 is a manufacturing method of the thermoplastic composite material of Claim 10 or Claim 11, Comprising:
The amorphous inorganic fine particles are amorphous aluminum phosphate fine particles, and the amorphous aluminum phosphate fine particles are formed through a process of mixing an aluminum nitrate aqueous solution and an ammonium phosphate aqueous solution. .

Invention of Claim 14 is a manufacturing method of the thermoplastic composite material as described in any one of Claims 10-13, Comprising:
The amorphous inorganic fine particles have a step of modifying the particle surface with an organosilane compound.

  According to the present invention, it is possible to provide a thermoplastic resin material having a very small change in refractive index with respect to temperature and a high light transmittance, an optical element using the same, and a method for producing a thermoplastic resin material.

  Details of the present invention will be described below.

  The thermoplastic composite material of the present invention is obtained by dispersing inorganic fine particles in a thermoplastic resin. The material which comprises a thermoplastic composite material is demonstrated in order.

<Inorganic fine particles>
The inorganic fine particles according to the present invention are amorphous inorganic fine particles containing aluminum, and the average particle size is preferably 1 nm or more and 50 nm or less, more preferably 1 nm or more and 30 nm or less, and further preferably 1 nm or more and 20 nm or less. . If the average particle size is less than 1 nm, it is difficult to disperse the inorganic fine particles, so that the desired performance may not be obtained. If the average particle size exceeds 50 nm, the resulting thermoplastic material composition becomes turbid. As a result, the transparency is lowered and the light transmittance may be less than 70%. Here, the average particle diameter means a diameter when converted to a sphere having the same volume as the particle, and the amorphous is a property indicating non-crystallinity, and is clear in X-ray diffraction or electron diffraction. A state in which the crystal structure cannot be confirmed.

  The shape of the inorganic fine particles is not particularly limited, but preferably spherical fine particles are used. Further, the particle size distribution is not particularly limited, but in order to achieve the effect of the present invention more efficiently, a particle having a relatively narrow distribution is preferably used rather than a particle having a wide distribution. Used. Specifically, a coefficient of variation (a value obtained by dividing a standard deviation by an average as an index of variation in measurement values, a dimensionless number) is preferably ± 30, and more preferably ± 10.

  Examples of such inorganic fine particles include aluminum hydroxide, aluminum oxide, aluminum phosphate, aluminosilicate, aluminoborate, potassium aluminate, sodium aluminate and the like. Further, compounds in which other metal elements are partially mixed in these compounds are also preferably used.

Furthermore, the dn / dT value, which is a temperature-dependent physical property value of the refractive index of the inorganic fine particles, is preferably 0 or more, and the dn / dT value of the inorganic fine particles is preferably 0 or more and 0.01 or less, Particularly preferably, it is 5 × 10 ⁻⁵ or more and 5 × 10 ⁻³ or less.

  The inorganic fine particles preferably used in the present invention are non-crystalline and have a dn / dT value of 0 or more, and do not cause aggregation or decomposition in a process such as heating when used for mixing with a resin. It is preferable that the characteristics do not change.

  In view of the above points, the inorganic fine particles preferably used in the present invention particularly preferably include an aluminum phosphate composition containing aluminum and phosphorus in a molar ratio of 0.9 to 1.1.

<Formation method of inorganic fine particles, surface modification>
The method for forming inorganic fine particles according to the present invention is preferably formed in a solution such as water or alcohol in order to form monodisperse amorphous particles having a small particle diameter. Any known method can be used as the particle forming method. For example, desired oxide fine particles can be obtained by using a metal halide or an alkoxy metal as a raw material 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. Further, a reaction crystallization method in which particles are precipitated by mixing two or more kinds of solutions, a uniform precipitation method (urea method) using precipitation due to pH change, and the like can be preferably used. In particular, it is preferably formed by a reaction crystallization method in which two or three soluble salt solutions are mixed in water or alcohol.

In the present invention, the surface of the particles can be further modified after the formation of particles by these methods in water or alcohol to form amorphous inorganic fine particles.
The method for modifying the surface 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. Examples of the surface modifier used for the surface treatment of inorganic fine particles include silane coupling agents, silicone oil, 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 may be performed simultaneously or at different times. 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.

  In the present invention, an organic silane compound generally called a silane coupling agent is preferably used as the surface modifier used for surface modification of the inorganic fine particles. Examples of the organic silane compound include tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane, tetraphenoxysilane, methyltrimethoxysilane, ethyltrimethoxysilane, propyltrimethoxysilane, methyltriethoxysilane, methyltriphenoxysilane, Ethyltriethoxysilane, phenyltrimethoxysilane, 3-methylphenyltrimethoxysilane, dimethyldimethoxysilane, diethyldiethoxysilane, diphenyldimethoxysilane, diphenyldiphenoxysilane, trimethylmethoxysilane, triethylethoxysilane, triphenylmethoxysilane, tri Examples include phenylphenoxysilane.

  Further, for example, a method of modifying the particle surface by adsorbing the dispersant to an acidic group or basic group present on the particle surface is also effective. In particular, a compound having a carboxylic acid group and / or a carboxylic anhydride group adsorbed on a basic group is preferably used. The compound having a carboxylic acid group is not particularly limited, and examples thereof include linear carboxylic acids such as stearic acid, dicarboxylic acids such as cyclohexane carboxylic acid and maleic acid having a cyclic structure, and mercapto groups and amide groups. A compound suitable for the type of resin to be mixed can be selected from those having a relatively small molecular weight, such as those having a substituent, and those having a carboxyl group in the main chain or side chain of the polymer compound. In addition, carboxylic acid anhydrides such as succinic anhydride and maleic anhydride, and acid-modified products obtained by reacting maleic anhydride with polymer chains are also preferably used.

  These compounds have different characteristics such as reaction rate, and compounds suitable for surface modification conditions can be used. Moreover, you may use only one type or may use multiple types together. Furthermore, the properties of the surface-modified fine particles obtained may vary depending on the compound used, and the affinity with the thermoplastic resin used to obtain the material composition can be achieved by selecting the compound used for the surface modification. is there.

  The ratio of the surface modification is not particularly limited, but the ratio of the surface modifier is preferably 10 to 99% by mass and more preferably 30 to 98% by mass with respect to the fine particles after the surface modification. preferable.

  In the present invention, inorganic fine particles can be used after being surface-modified as described above and dispersed in a nonpolar solvent. A nonpolar solvent here refers to the solvent whose content rate of solvents which have polar groups, such as water and alcohol, is 20% or less, Preferably it is 0 to 10%. The kind of the nonpolar solvent is preferably selected from those suitable for mixing with the resin which is the subsequent process. For example, toluene, xylene, hexane, cyclohexane, tetrahydrofuran (THF) and the like that can dissolve the resin are preferable. Can be used.

<< Thermoplastic resin made of organic polymer >>
Next, a thermoplastic resin composed of an organic polymer constituting the thermoplastic resin material of the present invention will be described.

  The thermoplastic resin according to the present invention is not particularly limited as long as it is a transparent thermoplastic resin material that is generally used as an optical material. However, in consideration of processability as an optical element, an acrylic resin, a cyclic olefin resin, A polycarbonate resin, a polyester resin, a polyether resin, a polyamide resin, or a polyimide resin is preferable. For example, compounds described in JP-A-2003-73559 can be given, and the preferable compounds are shown in Table 1.

  In a thermoplastic composite material, an organic polymer thermoplastic resin is an olefin having a cyclic structure obtained by hydrogenating a copolymer of an α-olefin having 2 to 20 carbon atoms and a cyclic olefin. And alicyclic hydrocarbon-based copolymer composed of a repeating unit having an alicyclic structure or a compound shown in paragraphs [0032] to [0054] of JP-A-7-145213 It is preferably a coalescence. Examples of the cyclic olefin resin preferably used in the present invention include, but are not limited to, ZEONEX (Nippon Zeon), APEL (Mitsui Chemicals), Arton (JSR), TOPAS (Chicona) and the like.

<Other ingredients>
In preparing the thermoplastic composite material of the present invention and in the molding process of the thermoplastic composite material (resin composition), various additives (also referred to as compounding agents) can be added as necessary. There are no particular restrictions on the additives, but stabilizers such as antioxidants, heat stabilizers, light stabilizers, weather stabilizers, UV absorbers and near infrared absorbers; resin modifiers such as lubricants and plasticizers An anti-clouding agent such as a soft polymer or an alcohol compound; a colorant such as a dye or a pigment; an antistatic agent, a flame retardant, or a filler. These compounding agents can be used alone or in combination of two or more, and the compounding amount is appropriately selected within a range not impairing the effects described in the present invention. In the present invention, it is particularly preferable that the polymer contains at least a plasticizer or an antioxidant.

[Plasticizer]
The plasticizer is not particularly limited, however, phosphate ester plasticizer, phthalate ester plasticizer, trimellitic ester plasticizer, pyromellitic acid plasticizer, glycolate plasticizer, citrate ester A plasticizer, a polyester plasticizer, etc. can be mentioned.

  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. Trimellitic plasticizers such as diethyl phthalate, dimethoxyethyl phthalate, dimethyl phthalate, dioctyl phthalate, dibutyl phthalate, di-2-ethylhexyl phthalate, butyl benzyl phthalate, diphenyl phthalate, dicyclohexyl phthalate, etc. For pyromellitic acid ester plasticizers such as phenyl trimellitate, triethyl trimellitate, etc. Examples of glycolate plasticizers such as tilpyromelitate, tetraphenylpyromellitate, and tetraethylpyromellitate include triacetin, tributyrin, ethylphthalylethyl glycolate, methylphthalylethyl glycolate, and butylphthalylbutyl glycolate. In the citrate plasticizer, for example, triethyl citrate, tri-n-butyl citrate, acetyl triethyl citrate, acetyl tri-n-butyl citrate, acetyl tri-n- (2-ethylhexyl) citrate, etc. Can be mentioned.

〔Antioxidant〕
Examples of the antioxidant include phenolic antioxidants, phosphorus antioxidants, sulfur antioxidants, etc. Among them, phenolic antioxidants, particularly alkyl-substituted phenolic antioxidants are preferable. By blending these antioxidants, it is possible to prevent lens coloring and strength reduction due to oxidative degradation during molding without lowering 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, but the polymer 100 according to the present invention. Preferably it is 0.001-5 mass parts with respect to a mass part, More preferably, it is 0.01-1 mass part.

  A conventionally well-known thing can be used as a phenolic antioxidant, for example, 2-t-butyl-6- (3-t-butyl-2-hydroxy-5-methylbenzyl) -4-methylphenyl acrylate, 2 , 4-di-t-amyl-6- (1- (3,5-di-t-amyl-2-hydroxyphenyl) ethyl) phenyl acrylate and the like, and JP-A Nos. 63-179953 and 1-168643. Acrylate compounds described in Japanese Patent Publication No. 1; octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 2,2'-methylene-bis (4-methyl-6-tert-butylphenol) ), 1,1,3-tris (2-methyl-4-hydroxy-5-t-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3,5 Di-t-butyl-4-hydroxybenzyl) benzene, tetrakis (methylene-3- (3 ', 5'-di-t-butyl-4'-hydroxyphenylpropionate)) methane [i.e. pentaerythrmethyl- Tetrakis (3- (3,5-di-t-butyl-4-hydroxyphenylpropionate))], triethylene glycol bis (3- (3-t-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, 3,5-triazine, 2-octylthio-4,6-bis- (3,5-di-t-butyl-4-oxyanilino) -1,3,5-tria Triazine group-containing phenol compounds such emissions; and the like.

  The phosphorus antioxidant is not particularly limited as long as it is usually used in the general resin industry. For example, triphenyl phosphite, diphenylisodecyl phosphite, phenyl diisodecyl phosphite, tris (nonylphenyl) Phosphite, tris (dinonylphenyl) phosphite, tris (2,4-di-t-butylphenyl) phosphite, 10- (3,5-di-t-butyl-4-hydroxybenzyl) -9,10 Monophosphite compounds such as -dihydro-9-oxa-10-phosphaphenanthrene-10-oxide; 4,4'-butylidene-bis (3-methyl-6-tert-butylphenyl-di-tridecyl phosphite ), 4,4'-isopropylidene-bis (phenyl-di-alkyl (C12-C15) phosphite) 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-thiodiprote. Pionate, pentaerythritol-tetrakis- (β-lauryl-thio-propionate), 3,9-bis (2-dodecylthioethyl) -2,4,8,10-tetraoxaspiro [5,5] undecane, etc. Can be mentioned.

(Light stabilizer)
Examples of the light-resistant stabilizer include benzophenone-based light-resistant stabilizer, benzotriazole-based light-resistant stabilizer, hindered amine-based light-resistant stabilizer, etc., but in the present invention, from the viewpoint of lens transparency, color resistance, etc., hindered amine-based It is preferable to use a light-resistant stabilizer. Among hindered amine light-resistant stabilizers (hereinafter also referred to as HALS), those having a polystyrene-equivalent Mn of 1,000 to 10,000 as measured by GPC using tetrahydrofuran (THF) as a solvent are preferable, 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, when HALS is blended by heat-melting and kneading into a block copolymer, a predetermined amount cannot be blended due to volatilization, foaming or silver streak occurs during heat-melt molding such as injection molding, etc. Processing stability decreases. 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. Conversely, 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 light resistance is reduced. 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}], 1,6-hexanediamine-N, N'-bis (2,2,6,6-tetramethyl- Polypiperidyl) 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 piperidine rings are bonded via a triazine skeleton. High molecular weight HALS; polymer of dimethyl succinate and 4-hydroxy-2,2,6,6-tetramethyl-1-piperidineethanol, 1,2,3,4-butanetetracarboxylic acid and 1,2,2 , 6,6-pentamethyl-4-piperidinol and 3,9-bis (2-hydroxy-1,1-dimethylethyl) -2,4,8,10-tetraoxaspiro [5,5] undecane Such engagement ester, piperidine ring linked to a high molecular weight HALS, and the like via an ester bond.
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.

The blending amount of the light-resistant stabilizer with respect to the thermoplastic composite material is preferably 0.01 to 20 parts by mass, more preferably 0.02 to 15 parts by mass, and particularly preferably 0.05 to 100 parts by mass of the polymer. -10 parts by mass. If the amount added is too small, the effect of improving light resistance cannot be obtained sufficiently, and coloring occurs when used outdoors for a long time. On the other hand, when the blending amount of HALS is too large, a part of the HALS is generated as a gas, or the dispersibility in the resin is lowered, so that the transparency of the lens is lowered.
In addition, by blending a thermoplastic composite material with a compound having the lowest glass transition temperature of 30 ° C. or less, it can be used for a long period of time without deteriorating various properties such as transparency, heat resistance, and mechanical strength. Can prevent white turbidity in high humidity environment.

<< Method for producing thermoplastic composite material >>
The thermoplastic composite material can be formed by mixing the aforementioned thermoplastic resin as a host material and inorganic fine particles, but the method is not particularly limited. That is, a method in which a thermoplastic resin and inorganic fine particles are separately produced and then mixed together, a method in which a thermoplastic resin is produced under conditions in which pre-made inorganic fine particles exist, and a pre-made thermoplastic resin exists. Any method can be employed, such as a method for producing inorganic fine particles under the conditions to be prepared, a method for producing both thermoplastic resin and inorganic fine particles simultaneously. Specifically, for example, two solutions of a solution in which a thermoplastic resin is dissolved and a dispersion in which inorganic fine particles are uniformly dispersed are uniformly mixed, and the resulting solution is arranged in a solution having poor solubility in the thermoplastic resin. Thus, a method for obtaining a target material composition can be preferably mentioned, but the method is not limited thereto.

  In the thermoplastic composite material, the degree of mixing of the thermoplastic resin and the inorganic fine particles is not particularly limited, but it is desirable that they are uniformly mixed in order to achieve the effect of the present invention more efficiently. If the degree of mixing is insufficient, there is a concern that it may affect the optical properties such as refractive index, Abbe number, and light transmittance, and it will also adversely affect resin processability such as thermoplasticity and melt moldability. There is a fear. The degree of mixing is considered to be affected by the production method, and it is important to select a method in consideration of the characteristics of the thermoplastic resin and inorganic fine particles used. In order to more uniformly mix both the thermoplastic resin and the inorganic fine particles, a method of directly bonding the thermoplastic resin and the inorganic fine particles can be suitably used in the present invention.

  The content of the inorganic fine particles is not particularly limited as long as the effect of the present invention can be exhibited, and can be arbitrarily determined depending on the types of the thermoplastic resin and the inorganic fine particles. The total content of the inorganic fine particles is preferably such that the volume fraction of the inorganic fine particles relative to the total volume of the thermoplastic composite material to be produced is 20% or more and 60% or less, more preferably 20% or more and 50% or less. Preferably, it is 30% or more and 50% or less. The volume fraction of inorganic fine particles here is expressed by the formula (x / a) / Y × where the specific gravity of the inorganic fine particles is a, the content is x grams, and the total volume of the resin of the produced thermoplastic composite material is Y milliliters. 100 is required. The content of inorganic fine particles can be determined by observing particle images with a transmission electron microscope (TEM) (information on the composition can also be obtained by local elemental analysis such as EDX), or the ash content contained in a given resin composition It can be calculated from the content weight of the predetermined particle composition obtained by the elemental analysis and the specific gravity of the particle composition.

  Furthermore, when mixing the thermoplastic resin and the inorganic fine particles, it is preferable to carry out the conditions under which the fine particles do not crystallize.

<Characteristics of thermoplastic composite material>
The thermoplastic composite material of the present invention is characterized in that the temperature change rate (dn / dT) of the refractive index is smaller than that of the thermoplastic resin as the base material.
Here, dn / dT, which is an index of the rate of change of refractive index n with respect to temperature T, indicates that the refractive index (n) of the material changes at a rate of dn / dT with respect to the change in temperature (T). Yes. The value of dn / dT can be obtained by measuring the refractive index of the resin material at each temperature and reading the temperature change rate of the refractive index.
As a method for measuring the refractive index, a preferable method can be selected according to the form of the thermoplastic composite material, for example, ellipsometry, spectral reflectance method, optical waveguide method, Abbe method, minimum deviation method, and the like.

In the thermoplastic composite material of the present invention, it is preferable that | dn / dT | which is the absolute value of dn / dT is 0 or more and 9.0 × 10 ⁻⁵ or less, and | dn / dT | is 0. As described above, it is preferably 5.0 × 10 ⁻⁵ or less. This dn / dT is preferably in the above-mentioned range in all wavelength regions, but if it is in the above-mentioned range in the wavelength region used when used as an optical element, an optical element having superior temperature stability than the conventional one Is preferable.

  The thermoplastic composite material of the present invention preferably has transparency in the visible region wavelength. The transparency of the thermoplastic composite material of the present invention is such that the light transmittance in the visible region wavelength is preferably 70% or more at an optical path length of 3 mm, more preferably 80% or more, and most preferably 90% or more. Is desirable. Such measurement is performed, for example, by a test according to ASTM D-1003 (3 mm thickness) standard. The visible region here means a wavelength region of 400 to 650 nm.

  In addition, the refractive index of the thermoplastic composite material of the present invention is determined by the combination of the thermoplastic resin and inorganic fine particles, but it is usually higher than the thermoplastic resin by selecting inorganic fine particles having a higher refractive index than the thermoplastic resin. Is preferred. Specifically, the range of about 1.45 to 2.0 is preferable, and more preferably 1.49 to 1.7.

  The thermoplastic composite material of the present invention is a material composition that has a low refractive index temperature dependency, high transparency, and excellent optical properties, and further has thermoplasticity and / or injection moldability. It is a thermoplastic material with excellent processability. This material having both excellent optical properties and moldability is a property that has not been achieved with the materials disclosed so far, and is composed of a specific thermoplastic resin and specific inorganic fine particles. It is thought that it contributes to this characteristic.

<< Optical element >>
Next, an optical element will be described as an example of a molded article formed using the thermoplastic composite material of the present invention.

  Examples of the optical element according to the present invention include optical resin lenses applicable to optical lenses and optical prisms. Specific examples of application of optical resin lenses to optical components are as follows.

For example, as an optical resin lens, an imaging system lens of a camera; a lens such as a microscope, an endoscope, a telescope lens; an all-light transmission lens such as a spectacle lens; a CD, a CD-ROM, a WORM (recordable optical disk), MO (rewritable optical disc; magneto-optical disc), MD (mini disc), optical disc pick-up lens such as DVD (digital video disc); laser beam printer fθ lens, laser scanning lens such as sensor lens; camera Finder type prism lenses.
Examples of optical disc applications include CD, CD-ROM, WORM (recordable optical disc), MO (rewritable optical disc; magneto-optical disc), MD (mini disc), DVD (digital video disc), and the like. Other optical applications include light guide plates such as liquid crystal displays; optical films such as polarizing films, retardation films and light diffusing films; light diffusing plates; optical cards;

  Among these, it is suitable as a pickup lens or a laser scanning system lens that requires low birefringence, and is most suitably used for a pickup lens.

<< Method for Manufacturing Optical Element (Optical Resin Lens) >>
Next, a method for manufacturing the optical element (optical resin lens) in the present embodiment will be described.

  An optical resin lens is prepared by first preparing a resin composition (a resin alone or a mixture of a resin and an additive) that is a thermoplastic composite material, and then obtaining the resin composition obtained. It is formed through a process of molding. That is, the molded product of the thermoplastic composite material of the present invention is obtained by molding the resin composition.

  The molding method is not particularly limited, but melt molding is preferable in order to obtain a molded product having excellent 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, and injection molding is preferred from the viewpoints of moldability and productivity.

  The molding conditions are appropriately selected depending on the purpose of use or molding method. For example, the temperature of the resin composition in injection molding (in the case of a resin alone or in a mixture of both a resin and an additive) is appropriate at the time of molding. 150 ° C. to 400 ° C. from the viewpoint of imparting fluidity to the resin to prevent sink marks and distortion of the molded product, preventing the occurrence of silver streak due to thermal decomposition of the resin, and effectively preventing yellowing of the molded product. The range of ° C is preferred, more preferably in the range of 200 ° C to 350 ° C, and particularly preferably in the range of 200 ° C to 330 ° C.

  The molded product according to the present invention 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, and is applied to an optical element. In this case, low birefringence, transparency, mechanical strength, heat resistance, and low water absorption can be improved.

<Optical pickup device>
Hereinafter, an optical pickup device 1 using an optical element that is a molded product of a thermoplastic resin composite material will be described with reference to FIG. Here, FIG. 1 is a schematic diagram showing the internal structure of the optical pickup device 1.

  In this embodiment, the target is a “high-density optical disk” using a so-called blue-violet laser light source having a used wavelength of 405 nm, the protective substrate thickness of this optical disk is 0.1 mm, and the storage capacity is about 30 GB.

As shown in FIG. 1, the optical pickup device 1 in this embodiment includes a semiconductor laser oscillator 2 that is a light source. On the optical axis of the blue light emitted from the semiconductor laser oscillator 2, a collimator 3, a beam splitter 4, a quarter wavelength plate 5, a diaphragm 6, and an objective lens 7 are arranged in a direction away from the semiconductor laser oscillator 2. Are sequentially arranged.
In addition, a sensor lens group 8 and a sensor 9 including two sets of lenses are sequentially disposed in a direction close to the beam splitter 4 and in a direction perpendicular to the optical axis of the blue light described above.

  The objective lens 7 that is an optical element is disposed at a position facing the optical disc D, and condenses the blue light emitted from the semiconductor laser oscillator 2 on one surface of the optical disc D. . Such an objective lens 7 is provided with a two-dimensional actuator 10, and the objective lens 7 is movable on the optical axis by the operation of the two-dimensional actuator 10.

Next, the operation of the optical pickup device 1 will be described.
The optical pickup device 1 in the present embodiment emits blue light from the semiconductor laser oscillator 2 at the time of recording information on the optical disc D or at the time of reproducing information recorded on the optical disc D. As shown in FIG. 1, the emitted blue light becomes a light ray L ₁ , is collimated to infinite parallel light through the collimator 3, and then is transmitted through the beam splitter 4 to be a quarter wavelength plate 5. Transparent. Furthermore, after sequentially passing through the aperture 6 and the objective lens 7 to form a converged spot on the information recording surface D ₂ through the protective substrate D ₁ of the optical disc D.

The light that forms the condensed spot is modulated by the information pits on the information recording surface D ₂ of the optical disc D and reflected by the information recording surface D ₂ . Then, the reflected light becomes a light beam L ₂ , is sequentially transmitted through the objective lens 7 and the diaphragm 6, is changed in polarization direction by the quarter wavelength plate 5, and is reflected by the beam splitter 4. After that, astigmatism is given through the sensor lens group 8, received by the sensor 9, and finally converted into an electric signal by being photoelectrically converted by the sensor 9.
Thereafter, such an operation is repeatedly performed, and the operation of recording information on the optical disc D and the operation of reproducing information recorded on the optical disc D are completed.

Incidentally, the magnitude of the thickness and the information pits of the protective substrate D ₁ of the optical disc D, also the numerical aperture NA required for the objective lens 7 different. In the present embodiment, the optical disc D is a high density, and its numerical aperture is set to 0.85.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto.

[Preparation of inorganic fine particles 1]
2 liters each of 7.06 mole aqueous solution of aluminum nitrate and 7.06 mole aqueous solution of disodium hydrogenphosphate were added to 3 liters of an aqueous solution containing 0.027 moles of disodium hydrogen phosphate, and 10 liters by double jet method. Added over a minute. During the fine particle formation, the pH was controlled to 3.0 using sulfuric acid, and the temperature was controlled to 30 ° C. After the addition, soluble salts were desalted and removed by ultrafiltration to obtain a 10% by mass aluminum phosphate dispersion. When the composition analysis of the obtained particle was performed, it was aluminum phosphate containing a small amount of sodium having a molar ratio of phosphorus to aluminum of 1.05. Further, as a result of X-ray diffraction, it was confirmed that the particles were amorphous particles having no clear crystal structure. Furthermore, 300 g of methanol and a 1 mol% nitric acid aqueous solution were added to 100 g of this dispersion. While this solution was stirred at 50 ° C., a mixed solution of 100 g of methanol and 6 g of cyclopentyltrimethoxysilane was added over 60 minutes, and then the mixture was further stirred for 24 hours for surface treatment. The obtained transparent dispersion was suspended in ethyl acetate and centrifuged to obtain a white fine powder. According to TEM observation, this powder had an average particle size of about 45 nm, and this was designated as inorganic fine particles 1.

[Preparation of inorganic fine particles 2]
Two liters of 7.06 mol of aluminum nitrate aqueous solution and 10.59 mol of disodium hydrogen phosphate aqueous solution were added to 3 liters of an aqueous solution containing 0.027 mol of disodium hydrogen phosphate, and 10 l by double jet method. Added over a minute. During the formation of the fine particles, the pH was controlled at 6.0 using sulfuric acid, and the temperature was controlled at 30 ° C. After the addition, soluble salts were desalted and removed by ultrafiltration to obtain a 10% by mass aluminum phosphate dispersion. When the composition analysis of the obtained particle was conducted, it was aluminum phosphate containing a small amount of sodium having a phosphorus to aluminum molar ratio of 1.15. Further, as a result of X-ray diffraction, it was confirmed that the particles were amorphous particles having no clear crystal structure. Furthermore, 300 g of methanol and a 1 mol% nitric acid aqueous solution were added to 100 g of this dispersion. While this solution was stirred at 50 ° C., a mixed solution of 100 g of methanol and 6 g of trimethylmethoxysilane was added over 60 minutes, and then the mixture was further stirred for 24 hours for surface treatment. The obtained transparent dispersion was suspended in ethyl acetate and centrifuged to obtain a white fine powder. According to TEM observation, this powder had an average particle size of about 45 nm, and this was designated as inorganic fine particles 2.

[Preparation of inorganic fine particles 3]
Two liters of 7.06 mol of aluminum nitrate aqueous solution and 10.59 mol of triammonium phosphate aqueous solution were added to 3 liter of an aqueous solution containing 0.027 mol of triammonium phosphate for 8 minutes by the double jet method. Added. During the fine particle formation, the pH was controlled to 6.5 with sulfuric acid, and the temperature was controlled to 25 ° C. After the addition, soluble salts were desalted and removed by ultrafiltration to obtain a 10% by mass aluminum phosphate dispersion. When the composition analysis of the obtained particle was performed, it was aluminum phosphate whose molar ratio of phosphorus to aluminum was 1.08. Further, as a result of X-ray diffraction, it was confirmed that the particles were amorphous particles having no clear crystal structure. According to TEM observation, this powder had an average particle diameter of about 20 nm, and this was designated as inorganic fine particles 3.

[Preparation of inorganic fine particles 4]
To 100 g of the dispersion of inorganic fine particles 3 obtained in [Preparation of inorganic fine particles 3], 300 g of methanol and a 1 mol% aqueous nitric acid solution were added. While this solution was stirred at 50 ° C., a mixed solution of 100 g of methanol and 6 g of trimethylmethoxysilane was added over 60 minutes, and then the mixture was further stirred for 24 hours for surface treatment. The obtained transparent dispersion was suspended in ethyl acetate and then centrifuged to obtain a white fine powder of aluminum phosphate surface-modified with an organosilane compound. According to TEM observation, this powder had an average particle diameter of about 20 nm, and this was designated as inorganic fine particles 4.

[Preparation of inorganic fine particles 5]
Two liters of 7.06 mol of aluminum nitrate aqueous solution and 7.06 mol of triammonium phosphate aqueous solution were added to 3 liters of an aqueous solution containing 0.027 mol of triammonium phosphate for 8 minutes by the double jet method. Added. During the fine particle formation, the pH was controlled to 4.5 using sulfuric acid, and the temperature was controlled to 25 ° C. After the addition, soluble salts were desalted and removed by ultrafiltration to obtain a 10% by mass aluminum phosphate dispersion. When the composition analysis of the obtained particle | grains was conducted, it was aluminum phosphate whose molar ratio of phosphorus with respect to aluminum is 1.01. Further, as a result of X-ray diffraction, it was confirmed that the particles were amorphous particles having no clear crystal structure. To 100 g of this dispersion, 300 g of methanol and a 1 mol% nitric acid aqueous solution were added. While this solution was stirred at 50 ° C., a mixed solution of 100 g of methanol and 6 g of trimethylmethoxysilane was added over 60 minutes, and then the mixture was further stirred for 24 hours for surface treatment. The obtained transparent dispersion was suspended in ethyl acetate and centrifuged to obtain a white fine powder. According to TEM observation, this powder had an average particle diameter of about 25 nm, and this was designated as inorganic fine particles 5.

[Preparation of inorganic fine particles 6]
3 liters of an aqueous solution containing 0.027 moles of triammonium phosphate and 2 liters each of 7.06 moles of aluminum nitrate aqueous solution and 6.3 moles of triammonium phosphate aqueous solution were applied for 8 minutes by the double jet method. Added. During the fine particle formation, the pH was controlled to 4.5 using sulfuric acid, and the temperature was controlled to 25 ° C. After the addition, soluble salts were desalted and removed by ultrafiltration to obtain a 10% by mass aluminum phosphate dispersion. The composition analysis of the obtained particles revealed that the aluminum phosphate had a molar ratio of phosphorus to aluminum of 0.92. Further, as a result of X-ray diffraction, it was confirmed that the particles were amorphous particles having no clear crystal structure. To 100 g of this dispersion, 300 g of methanol and a 1 mol% nitric acid aqueous solution were added. While this solution was stirred at 50 ° C., a mixed solution of 100 g of methanol and 6 g of trimethylmethoxysilane was added over 60 minutes, and then the mixture was further stirred for 24 hours for surface treatment. The obtained transparent dispersion was suspended in ethyl acetate and centrifuged to obtain a white fine powder. According to TEM observation, this powder had an average particle size of about 25 nm, and this was designated as inorganic fine particles 6.

[Preparation of inorganic fine particles 7]
3 liters of an aqueous solution containing 0.027 moles of triammonium phosphate and 2 liters of each of 7.06 moles of aluminum nitrate aqueous solution and 10.59 moles of triammonium phosphate aqueous solution were applied for 20 minutes by the double jet method. Added. During the fine particle formation, the pH was controlled to 6.5 with sulfuric acid, and the temperature was controlled to 40 ° C. After the addition, soluble salts were desalted and removed by ultrafiltration to obtain a 10% by mass aluminum phosphate dispersion. When the composition analysis of the obtained particle was performed, it was aluminum phosphate whose molar ratio of phosphorus to aluminum was 1.06. Further, as a result of X-ray diffraction, it was confirmed that the particles were amorphous particles having no clear crystal structure. To 100 g of this dispersion, 300 g of methanol and a 1 mol% nitric acid aqueous solution were added. While this solution was stirred at 50 ° C., a mixed solution of 100 g of methanol and 6 g of trimethylmethoxysilane was added over 60 minutes, and then the mixture was further stirred for 24 hours for surface treatment. The obtained transparent dispersion was suspended in ethyl acetate and centrifuged to obtain a white fine powder. According to TEM observation, this powder had an average particle diameter of about 60 nm, and this was designated as inorganic fine particles 7.

[Preparation of inorganic fine particles 8]
In 3 liters of water, 3 liters of an aqueous solution containing 0.6 mol of aluminum nitrate and 3 liters of an aqueous solution containing 3.45 mol of sodium carbonate were added over 10 minutes by the double jet method. After the addition was completed, the soluble salts were desalted and removed by ultrafiltration to obtain a 10% by mass aluminum hydroxide dispersion. As a result of composition analysis and X-ray diffraction of the obtained particles, it was confirmed that the particles were amorphous aluminum hydroxide particles having no clear crystal structure.
The particles were subjected to surface modification in the same manner as in the preparation of the inorganic fine particles 4 to obtain white fine powder. According to TEM observation, this powder had an average particle size of about 30 nm, and this was designated as inorganic fine particles 8.

[Preparation of inorganic fine particles 9]
300 g of methanol and a 1 mol% nitric acid aqueous solution were added to 5 g of aluminum oxide C (average particle size: about 13 nm) fine particles manufactured by Nippon Aerosil Co., Ltd., which are γ-type crystal particles. While stirring this solution at 50 ° C., a mixed solution of 100 g of methanol and 6 g of cyclopentyltrimethoxysilane was added over 60 minutes, and then further stirred for 24 hours. The obtained transparent dispersion was suspended in ethyl acetate and centrifuged to obtain a white fine powder. According to TEM observation, this powder had an average particle diameter of about 15 nm.

<< Production of thermoplastic composite material >>
In the production of the thermoplastic composite materials 1 to 15 described later, thermoplastic resins (cyclic olefin resin and acrylic resin) described in Table 2 below are prepared as the resins used. Further, as preparation before kneading inorganic fine particles in the prepared thermoplastic resin, each resin is dried at 80 ° C. for 8 hours, and the inorganic fine particles 1 to 9 used for producing the thermoplastic composite materials 1 to 14 and The fine particles of Aluminum Oxide C used in the production of the thermoplastic composite material 15 are each dried at 200 ° C. for 4 hours.

[Preparation of thermoplastic composite material 1]
40 g of inorganic fine particle 1 powder was added to 35 g of molten ZEONEX 340R made by Nippon Zeon, and thermoplastic composite material 1 in which the inorganic fine particles were dispersed was prepared by melt kneading. The kneading conditions were as follows: using a kneader manufactured by HAAKE, kneading for 5 minutes after the addition of the powder was completed at a preset temperature of 200 ° C. and 30 rpm.

[Production of thermoplastic composite material 2]
An inorganic fine particle 2 is used in place of the inorganic fine particle 1, and the inorganic fine particle 2 is adjusted so that the added amount of the inorganic fine particle and the content of the inorganic fine particle contained in the thermoplastic composite material are the amounts shown in Table 2. A thermoplastic composite material was prepared in the same manner as the preparation of the thermoplastic composite material 1 except that the fine particles were dispersed, and the thermoplastic composite material obtained was used as the thermoplastic composite material 2.

[Production of thermoplastic composite materials 3 to 6]
The inorganic fine particles 4 are used in place of the inorganic fine particles 1 and the inorganic fine particles 4 are adjusted so that the added amount of the inorganic fine particles and the content of the inorganic fine particles contained in the thermoplastic composite material are the amounts shown in Table 2. A thermoplastic composite material was produced in the same manner as the production of the thermoplastic composite material 1 except that the fine particles were dispersed, and the obtained thermoplastic composite materials were designated as thermoplastic composite materials 3 to 6.

[Preparation of thermoplastic composite material 7]
The inorganic fine particles 5 are used instead of the inorganic fine particles 1, and the inorganic fine particles 5 are adjusted so that the added amount of the inorganic fine particles and the content of the inorganic fine particles contained in the thermoplastic composite material are the amounts shown in Table 2. A thermoplastic composite material was produced in the same manner as the production of the thermoplastic composite material 1 except that the fine particles were dispersed, and the resulting thermoplastic composite material was used as the thermoplastic composite material 7.

[Preparation of thermoplastic composite material 8]
The inorganic fine particles 6 are used instead of the inorganic fine particles 1 and the inorganic fine particles 6 are adjusted so that the added amount of the inorganic fine particles and the content of the inorganic fine particles contained in the thermoplastic composite material are the amounts shown in Table 2. A thermoplastic composite material was prepared in the same manner as the preparation of the thermoplastic composite material 1 except that the fine particles were dispersed, and the resulting thermoplastic composite material was used as the thermoplastic composite material 8.

[Preparation of thermoplastic composite material 9]
An inorganic fine particle 7 is used in place of the inorganic fine particle 1, and the inorganic fine particle 7 is adjusted so that the added amount of the inorganic fine particle and the content of the inorganic fine particle contained in the thermoplastic composite material are the amounts shown in Table 2. A thermoplastic composite material was produced in the same manner as the production of the thermoplastic composite material 1 except that the fine particles were dispersed, and the resulting thermoplastic composite material was used as the thermoplastic composite material 9.

[Production of thermoplastic composite material 10]
An inorganic fine particle 8 is used instead of the inorganic fine particle 1 and the inorganic fine particle 8 is adjusted so that the added amount of the inorganic fine particle and the content of the inorganic fine particle contained in the thermoplastic composite material are the amounts shown in Table 2. A thermoplastic composite material was prepared in the same manner as the preparation of the thermoplastic composite material 1 except that the fine particles were dispersed, and the resulting thermoplastic composite material was used as the thermoplastic composite material 10.

[Production of thermoplastic composite material 11]
Inorganic fine particles 9 are used in place of the inorganic fine particles 1, and the inorganic fine particles 9 are adjusted so that the added amount of the inorganic fine particles and the content of the inorganic fine particles contained in the thermoplastic composite material are the amounts shown in Table 2. A thermoplastic composite material was prepared in the same manner as the preparation of the thermoplastic composite material 1 except that the fine particles were dispersed, and the resulting thermoplastic composite material was used as the thermoplastic composite material 11.

[Production of thermoplastic composite material 12]
Except using Mitsui Chemicals' cyclic olefin resin APL5014DP for the thermoplastic resin, inorganic fine particles are dispersed by the same method as the production of the thermoplastic composite material 5, and the resulting thermoplastic composite material is used as the thermoplastic composite material 12. .

[Preparation of thermoplastic composite material 13]
A thermoplastic composite material is produced in the same manner as the production of the thermoplastic composite material 12 except that the inorganic fine particles 5 are dispersed in place of the inorganic fine particles 4, and the resulting thermoplastic composite material is thermoplastic composite. Material 13 was obtained.

[Production of Thermoplastic Composite Material 14]
40 g of inorganic fine particle 3 powder was added to 42 g of melted acrylic resin Acrypet VH manufactured by Mitsubishi Rayon Co., and a thermoplastic composite material 14 in which inorganic fine particles were dispersed was prepared by melt kneading. The kneading conditions were as follows: using a kneader manufactured by HAAKE, at a preset temperature of 180 ° C. and 30 rpm for 5 minutes after completion of the powder addition.

[Production of thermoplastic composite material 15]
A thermoplastic composite material was prepared in the same manner as the production of the thermoplastic composite material 14 except that the inorganic fine particles were dispersed using aluminum oxide C (average particle size: about 13 nm) fine particles manufactured by Nippon Aerosil Co., Ltd. instead of the inorganic fine particles 3. The thermoplastic composite material produced and obtained was designated as thermoplastic composite material 15.

<Evaluation of thermoplastic composite material>
(Evaluation of refractive index)
Each of the thermoplastic composite materials 1 to 15 was melted and heat-molded to prepare a test plate having a thickness of 3 mm, and the refraction at a wavelength of 588 nm was performed using an automatic refractometer KPR-200 manufactured by Kalnew Optical Industry Co., Ltd. The rate was measured by changing the sample temperature from 10 ° C to 60 ° C. The refractive index at 25 ° C. is nd 25, the temperature change rate of the refractive index from 10 ° C. to 60 ° C. is dn / dT, and the obtained results are shown in Table 2.

(Measurement of transmittance)
Each of the prepared thermoplastic composite materials 1 to 15 was melted and heat-molded to prepare each test plate having a thickness of 3.0 mm. Each of the plates was immediately subjected to a method in accordance with ASTM D1003 by Tokyo Denshoku Co., Ltd. ) The light transmittance was measured using TURBIDITY METER T-2600DA manufactured by this company, and the measured light transmittance was defined as transmittance A (%). Next, each test plate was allowed to stand for 48 hours in an environment of 65 ° C., and then the light transmittance after the forced deterioration treatment was measured by the same method as described above, and this was defined as transmittance B (%). .
In addition, when the measured light transmittance was 70% or less, it was determined that the transparency was poor and it was not suitable for an optical element.

The results obtained as described above are shown in Table 2.

As is apparent from the results shown in Table 2, the thermoplastic composite material of the present invention (thermoplastic composite materials 1-8, 11, 12, 15) is a thermoplastic composite material of the comparative example (thermoplastic composite material 9, 10, 13, and 14), it can be seen that the temperature dependence of the refractive index is small and the transparency is high. Furthermore, even after the forced deterioration treatment is performed, it can be seen that the degree of decrease in transparency is extremely small, and it is extremely useful as a resin material used for optical elements.
Furthermore, as a result of producing and evaluating a plastic optical element using the thermoplastic composite material, the optical element of the present invention has good optical characteristics and is a high-density recording medium such as Blu-ray Disc or HD DVD. Even when irradiated with a blue laser used for recording and reproduction for a long time, it was confirmed that the material was excellent in material alteration resistance such as white turbidity.

It is a schematic diagram which shows the internal structure of the optical pick-up apparatus provided with the objective lens which is the optical element which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical pick-up apparatus 2 Semiconductor laser oscillator 3 Collimator 4 Beam splitter 5 1/4 wavelength plate 6 Aperture 7 Objective lens (optical element)
8 Sensor lens group 9 Sensor 10 Two-dimensional actuator D Optical disk D ₁ Protective substrate D ₂ Information recording surface

Claims (14)

  A transparent thermoplastic composite material in which fine particles having an average particle diameter of 1 nm or more and 50 nm or less are dispersed in a thermoplastic resin made of an organic polymer, wherein the fine particles contain amorphous inorganic fine particles A thermoplastic composite material characterized in that   The thermoplastic composite material according to claim 1, wherein the amorphous inorganic fine particles are formed in a liquid phase.   The heat according to claim 1 or 2, wherein the amorphous inorganic fine particles are amorphous aluminum phosphate fine particles having a molar ratio of phosphorus to aluminum of 0.9 or more and 1.1 or less. Plastic composite material.   The thermoplastic composite material according to claim 3, wherein the amorphous aluminum phosphate fine particles are formed by mixing an aluminum salt solution and a phosphate solution.   The thermoplastic composite material according to claim 3, wherein the amorphous aluminum phosphate fine particles are formed by mixing an aluminum nitrate aqueous solution and an ammonium phosphate aqueous solution.   The thermoplastic composite material according to any one of claims 1 to 5, wherein the amorphous inorganic fine particles have a particle surface modified with an organosilane compound.   The thermoplastic composite material according to any one of claims 1 to 6, wherein the volume fraction of the amorphous inorganic fine particles is 20% or more and 60% or less.   The thermoplastic resin includes at least one of acrylic resin, cyclic olefin resin, polycarbonate resin, polyester resin, polyether resin, polyamide resin, and polyimide resin. The thermoplastic composite material according to one item.   An optical element formed by using the thermoplastic composite material according to any one of claims 1 to 8. A method for producing a transparent thermoplastic composite material, comprising:
The method comprises a step of dispersing fine particles having an average particle diameter of 1 nm or more and 50 nm or less in a thermoplastic resin made of an organic polymer, and the fine particles are formed using amorphous inorganic fine particles containing aluminum. A method for producing a thermoplastic composite material.   The method for producing a thermoplastic composite material according to claim 10, wherein the amorphous inorganic fine particles include a step of forming in the liquid phase.   The amorphous inorganic fine particles are amorphous aluminum phosphate fine particles, and the amorphous aluminum phosphate fine particles are formed through a step of mixing an aluminum salt solution and a phosphate solution. The manufacturing method of the thermoplastic composite material of Claim 10 or Claim 11.   The amorphous inorganic fine particles are amorphous aluminum phosphate fine particles, and the amorphous aluminum phosphate fine particles are formed through a process of mixing an aluminum nitrate aqueous solution and an ammonium phosphate aqueous solution. The manufacturing method of the thermoplastic composite material of Claim 10 or Claim 11.   The method for producing a thermoplastic composite material according to any one of claims 10 to 13, further comprising a step of modifying a particle surface with an organosilane compound with respect to the amorphous inorganic fine particles.

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