JP2009235325A - Production method for optical resin material, optical resin material, and optical element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a production method for an optical resin material having a refractive index and transparency suitable as an optical element, having a very low refractive index change with respect to a temperature, and having excellent moldability and heat resistance, and to provide the optical resin material and the optical element using the same. <P>SOLUTION: This production method for the optical resin material containing an inorganic oxide fine particle having 1 nm or more to 50 nm or less of average particle size in a host resin material, includes a process for substituting a dispersion of the inorganic oxide fine particle with a solvent by ultrafiltration, and a process for bringing a surface of the inorganic oxide fine particle into an hydrophobic state in the solvent. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an optical resin material and an optical element, and in particular, a method for producing an optical resin material suitably used as a lens, a filter, a grating, an optical fiber, a flat optical waveguide, and the like, an optical resin material, and an optical element using the same About.

  Examples of the optical element that transmits light and achieves a desired optical function include optical lenses and correction elements used in various optical devices. Examples thereof include an imaging optical system used in an imaging apparatus such as a silver salt camera, a digital camera, and a medical imaging apparatus, an optical system of an optical pickup apparatus, an optical element used in an optical communication module, and the like. In general, an optical element made of glass or plastic is used.

  In particular, plastic optical elements can be molded by injection molding, extrusion molding, and the like, and can be molded at a relatively low temperature, and therefore can be manufactured at a lower cost than glass optical elements. There is a strong demand for an optical element made of plastic that can replace this optical element.

  Conventionally, an optical element using a thermoplastic resin is widely known as an optical element used in an imaging optical system or an optical system of an optical pickup device. For example, a copolymer of a cyclic olefin and an α-olefin has been proposed as a thermoplastic resin applicable to an optical element of an optical pickup device (see, for example, Patent Document 1).

  However, optical elements using thermoplastic resins have lower heat resistance compared to glass optical elements, and optical performance may vary when exposed to high temperatures, so high optical accuracy is required. When used as an optical element for an imaging optical system or an optical element for an optical system of an optical pickup device, there may be a problem. Further, the imaging optical system may be exposed to various environments depending on the shooting environment, and the optical pickup device generates heat by driving the device for tracking and focusing, and the optical element is exposed to a high temperature. There is a case.

  On the other hand, for the purpose of improving rigidity and dimensional stability, a resin composition containing a thermoplastic resin and an oxidizing compound having a hydrophobic group and a polar group on its surface (see, for example, Patent Document 2) is disclosed. However, these resin compositions use crystalline silica or amorphous silica particles such as colloidal silica at the time of production, and the strength and rigidity of the resin composition due to the three-dimensional structure generated by the crosslinking reaction between the particles and the host resin material. Therefore, 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.

  In addition, even in the manufacturing process of an imaging device or the like, when a component incorporating a lens passes through a solder reflow process, the lens itself is also exposed to a high temperature of about 260 ° C., so that the heat resistance is further increased. Has been demanded.

  The thermoplastic resin is soft and melts at a relatively low temperature, so that the processability is good, but the molded lens has a drawback that it is easily deformed by heat. For this reason, thermosetting resins such as silicone resins have been studied as other plastic materials used as optical lenses (see, for example, Patent Document 3). However, a thermosetting resin that satisfies moldability and heat resistance and can be used as an optical lens has not been obtained so far.

  Further, a method of dispersing both composite metal oxide nanoparticles produced by a sol-gel method in a resin to achieve both rigidity and transparency is disclosed (for example, see Patent Documents 4 and 5).

However, the methods of Patent Documents 4 and 5 do not consider characteristics such as moldability and heat resistance. In addition, the resin materials produced by the methods described in these documents are not sufficiently satisfactory because of deterioration in transparency due to deformation, coloring, and particle aggregation at high temperatures such as a solder reflow process.
JP 2002-105131 A JP 2004-269773 A JP 2004-146554 A JP 2004-292698 A JP 2005-146042 A

  The present invention has been made in view of the above problems, and the object of the present invention is to have a refractive index and transparency suitable as an optical element, have a very small change in refractive index with respect to temperature, and have moldability and heat resistance. An excellent method for producing an optical resin material, an optical resin material, and an optical element using the same.

  The above object of the present invention is achieved by the following configurations.

  1. A method for producing an optical resin material containing inorganic oxide fine particles having an average particle diameter of 1 nm or more and 50 nm or less in a host resin material, wherein the dispersion of the inorganic oxide fine particles is solvent-substituted by ultrafiltration A method for producing an optical resin material, comprising: a step; and a step of subjecting the inorganic oxide fine particles to a surface hydrophobization treatment in a solvent.

  2. 2. The method for producing an optical resin material as described in 1 above, wherein the step of subjecting the inorganic oxide fine particle dispersion to solvent substitution by ultrafiltration is performed after the surface hydrophobization treatment step of the inorganic oxide fine particles. .

  3. 3. The optical resin material as described in 1 or 2 above, further comprising a step of obtaining a dry powder of the inorganic oxide fine particles after the step of solvent substitution of the dispersion of the inorganic oxide fine particles by ultrafiltration. Manufacturing method.

  4). 4. The method for producing an optical resin material according to any one of 1 to 3, wherein the inorganic oxide fine particles are composite oxide fine particles composed of silicon and another metal element.

  5). 5. The method for producing an optical resin material according to any one of 1 to 4, wherein the surface hydrophobization treatment of the inorganic oxide fine particles is performed using a silicon compound.

  6). An optical resin material produced by the production method according to any one of 1 to 5 above.

  7. 7. An optical element molded using the optical resin material described in 6 above.

  INDUSTRIAL APPLICABILITY According to the present invention, a method for producing an optical resin material having an appropriate refractive index and transparency as an optical element, an extremely small change in refractive index with respect to temperature, and excellent in moldability and heat resistance, and an optical resin A material and an optical element using the material can be provided.

  The best mode for carrying out the present invention will be described in detail below, but the present invention is not limited thereto.

  The present invention will be described in more detail.

<Inorganic oxide fine particles>
The composition of the inorganic oxide fine particles according to the present invention is not particularly limited as long as it does not cause absorption, light emission, fluorescence, or the like in the wavelength region used as an optical element. For example, Li, Na, Mg, Al, Si, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Rb, Sr, Y, Nb, Zr, Mo, Ag, Cd, In, Sn, Sb, Cs, Ba, An oxide of one or more elements such as La, Ta, Hf, W, Ir, Tl, Pb, Bi, and rare earth metal can be used.

  In order to exhibit high transparency when mixed with a resin as in the present invention, it is preferable to change the refractive index of the fine particles with a host resin, and therefore composite oxide fine particles composed of two or more elements are preferred, particularly silicon. It is preferably a composite oxide fine particle in which an oxide (hereinafter referred to as “silica”) and one or more metal oxides other than silicon are combined, and silica and Al, Ti, Nb, Zr, Y, W, Complex oxide fine particles in which metal oxides such as La, Gd, and Ta are complexed are more preferable.

  The composition distribution of the composite oxide particles is not particularly limited, and silica and other metal oxides may be dispersed substantially uniformly or may form a core shell. In the composite oxide particles, silica and other metal oxides are distributed in an average distribution without localization, and there is no refractive index distribution in the inorganic fine particles, and light scattering in the inorganic fine particles. Therefore, it is more preferable that silica and other metal oxides are averagely distributed in the composite oxide particles. In addition, silica and other metal oxides constituting the composite oxide particles may exist as crystals or may be amorphous.

  In the composite oxide particles, the content ratio of silica and a metal oxide other than silica can be arbitrarily determined depending on the type of metal oxide and the refractive index value of the inorganic fine particles to be produced.

  The inorganic fine particles dispersed in the resin in the optical resin material may be one kind of inorganic fine particles or a combination of plural kinds of inorganic fine particles as long as the light transmittance is not lowered. By using a plurality of types of inorganic fine particles having different properties, the optical characteristics required for the optical element can be improved more efficiently.

  The inorganic oxide fine particles of the present invention have an average particle size of 1 nm or more and 50 nm or less, more preferably 1 nm or more and 20 nm or less, and further preferably 1 nm or more and 15 nm or less. The average particle diameter of the fine particles is an average value of the diameters when the simple particles (including simple particles constituting the aggregate) are converted into spheres having the same volume, and this value indicates that the fine particles are dispersed in the resin. It can be evaluated from a transmission electron micrograph of a section of the resin material. When the average particle diameter is less than 1 nm, it is difficult to disperse the fine particles and the desired performance may not be obtained. Therefore, the average particle diameter is preferably 1 nm or more, and when the average particle diameter exceeds 50 nm. Since the resulting resin material composition may become cloudy, the transparency may be reduced and the light transmittance may be less than 80%. Therefore, the average particle size needs to be 50 nm or less.

  Further, the shape of the fine particles is not particularly limited, but spherical fine particles are preferably used. Specifically, the minimum diameter of the fine particles (minimum value of the distance between the tangents when drawing two tangents in contact with the outer periphery of the fine particles) / maximum diameter (the relevant value when drawing two tangents in contact with the outer periphery of the fine particles) The maximum value of the distance between tangents) is preferably 0.5 to 1.0, and more preferably 0.7 to 1.0.

  In addition, 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 than that having a wide distribution is preferably used. It is done. In particular, if even a small number of particles having a particle diameter of 100 nm or more are present, the light transmittance is remarkably deteriorated. Therefore, the coefficient of variation (the value obtained by dividing the standard deviation by the average as an index of variation in the measured value, the dimensionless number) is 30 or less. In particular, it is preferably 10 or less.

  In addition, it is desirable that the inorganic oxide fine particles have a small difference in refractive index from the host resin material described later. According to the study by the present inventors, if the difference in refractive index between the host resin material and the inorganic oxide fine particles dispersed in the resin is small, scattering is difficult to occur when light is transmitted, and the optical property has high transparency. It was found that a resin material can be obtained. In addition, the larger the inorganic oxide fine particles dispersed in the resin, the easier it is to scatter light when transmitting light, but when the difference in refractive index between the resin and the dispersed inorganic oxide fine particles is small, It has been found that even when relatively large inorganic fine particles are used, the frequency of light scattering is reduced, and transparency can be maintained even if the content of the inorganic fine particles is increased.

  As described above, the refractive index difference between the inorganic oxide fine particles and the host resin material is preferably 0.15 or less, more preferably the refractive index difference is 0.1 or less, more preferably the refractive index difference is 0.05 or less. It is.

  And although the refractive index of inorganic oxide microparticles | fine-particles which satisfy | fill such a refractive index difference changes with resin compositions, since the refractive index of resin exists in the range of 1.5-1.6 normally, it is 1.5-1.75. It is preferable that it is, and it is still more preferable that it is 1.5-1.65.

  In particular, in the present invention, the optical resin material in which the inorganic oxide fine particles are dispersed has a light transmittance that can be used as an optical element, and a refractive index nd25 measured by using a sodium D line as a light source at 25 ° C. is 1. It is preferable to adjust the refractive index of the inorganic oxide fine particles so as to be 0.5 or more and 1.7 or less.

  The refractive index is, for example, measured by an Abbe refractometer or the like according to ASTM D542 standard, and values described in various documents can be used. Further, the inorganic oxide fine particles are dispersed in various solvents having a adjusted refractive index, the absorbance of the dispersion is measured, and the refractive index of the solvent having the minimum value is measured. Refractive index can be confirmed.

<< Formation method of inorganic oxide fine particles >>
As the method for forming inorganic oxide fine particles according to the present invention, any known method can be used as long as the oxide fine particles having a small particle diameter can be formed. In general, inorganic oxide particles are prepared by thermal decomposition (a method in which raw materials are thermally decomposed to obtain fine particles), spray drying, flame spraying, plasma, gas phase reaction, and freeze drying. , Heated kerosene method, heated petroleum method, precipitation method (coprecipitation method), hydrolysis method (salt aqueous solution method, alkoxide method, sol-gel method), hydrothermal method (precipitation method, crystallization method, hydrothermal decomposition method, hydrothermal method) Oxidation method). The present invention is characterized in that inorganic oxide fine particles prepared by these methods are dispersed in a solvent, and the subsequent solvent replacement step and ultrafiltration step are performed.

  The method for producing the inorganic oxide fine particles dispersed in the solvent is not particularly limited, and the method of dispersing the inorganic oxide fine particle powder in the solvent using a dispersion apparatus even in the method of preparing the particle dispersion in the solution. But it ’s okay. As the dispersion device, an ultrasonic dispersion machine, a medium stirring mill such as a bead mill, or the like can be used.

  Further, in the case of using complex oxide fine particles having a core-shell structure as the inorganic oxide fine particles of the present invention, it is also preferable to form a shell layer in the solvent after the core particles are dispersed in the solvent.

<Surface hydrophobization treatment of inorganic oxide fine particles>
The production method of the present invention includes a step of subjecting the inorganic oxide fine particles to a surface hydrophobization treatment in a solvent. Examples of the hydrophobic treatment method include a wet heating method, a wet filtration method, a dry stirring method, an integral blend method, and a granulation method. When the surface of uniform oxide particles having a volume average particle size of 100 nm or less is subjected to a hydrophobic treatment, a dry stirring method from the viewpoint of suppressing particle aggregation and the surface adsorbent adsorbing uniformly on the particles A wet stirring method is preferred.

  As the solvent for the wet stirring method, the nonpolar solvent is preferably hexane, heptane, or a polar solvent, preferably toluene, methanol, ethanol, acetone, water, acetonitrile, pyridine, dimethylformamide (DMF), methyl ethyl ketone (MEK), methyl-i-butyl ketone. (MIBK), 1,4 dioxane, and other ethers or ketones are preferred, but ketones are preferred without risk of explosion during concentration.

  Examples of the method of hydrophobizing the surface of the inorganic oxide fine particles include a surface treatment with a coupling agent or the like, a polymer graft, and a hydrophobization treatment with a mechanochemical.

  Examples of the reagent used for the hydrophobic treatment on the surface of the inorganic oxide fine particles include a silane coupling agent, a silicone oil type, a titanate type, an aluminate type and a zirconate type coupling agent. These are not particularly limited, and can be appropriately selected depending on the types of inorganic oxide fine particles and thermosetting resin. Further, two or more various hydrophobizing treatments may be performed simultaneously or at different times.

As a hydrophobizing agent for silicon compounds preferably used in the present invention,
Silazanes: vinylsilazane, hexamethyldisilazane, tetramethyldisilazane,
Chlorosilanes: trimethylchlorosilane, dimethyldichlorosilane, methyltrichlorosilane, vinyltrichlorosilane,
Alkoxysilanes: trimethylmethoxysilane, dimethyldimethoxysilane, methyltrimethoxysilane, vinyltrimethoxysilane,
Silane coupling agents: vinyltriacetoxysilane, vinyltris (methoxyethoxy) silane, vinyltrimethoxysilane, vinyltriethoxysilane, allyltrimethoxysilane,
Etc. are applicable, and trimethylmethoxysilane, dimethyldimethoxysilane, methyltrimethoxysilane, hexamethyldisilazane, trimethylchlorosilane and the like are preferable.

  Silicone oil-based hydrophobizing agents include straight silicone oils such as dimethyl silicone oil, methylphenyl silicone oil, and methyl hydrogen silicone oil, amino-modified silicone oil, epoxy-modified silicone oil, carboxyl-modified silicone oil, and 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 Higher fatty acid containing modified silicone oil, modified silicone oil and fluorine-modified silicone oil can be used.

  As the hydrophobizing agent, silane-based hydrophobizing agents are preferable, and silazanes, chlorosilanes, and silane coupling agents are particularly preferable.

  These hydrophobizing agents may be appropriately diluted with hexane, toluene, methanol, ethanol, acetone or the like.

  These hydrophobizing agents may be used alone or in combination, and furthermore, inorganic oxide fine particles (hydrophobic oxide particles) after the hydrophobizing treatment obtained by the hydrophobizing agent used. However, the affinity with the thermosetting resin used in obtaining the optical resin material can be increased by selecting a hydrophobizing agent. The proportion of the hydrophobizing agent is not particularly limited, but the proportion of the hydrophobizing agent is 10 to 99% by mass with respect to the inorganic oxide fine particles (hydrophobic oxide particles) after the hydrophobizing treatment. It is preferable that it is 30-98 mass%.

  In addition, between the said particle | grain formation process and the said hydrophobization process process, the process of tetramethoxysilane or tetraethoxysilane is performed with respect to the surface of the inorganic oxide fine particle obtained after the particle | grain formation process, The said inorganic oxide fine particle A silica layer made of tetramethoxysilane or tetraethoxysilane may be formed on the surface of this (silica layer forming step), and then the hydrophobic treatment may be performed on the surface of the silica layer.

<< Solvent replacement by ultrafiltration >>
Next, solvent replacement by ultrafiltration will be described.

  The present invention is characterized by including a solvent replacement step by ultrafiltration of the particle dispersion together with the surface treatment step described above. The solvent replacement step is a step of substituting the solvent of the particle dispersion with a solvent suitable for the surface treatment step as a pre-step of the surface treatment step, or a removal of by-products during the surface treatment as a post-step of the surface treatment step. It is preferably carried out as a step of substitution with a solvent suitable for drying the inorganic oxide fine particles after the surface treatment and mixing with the resin. Therefore, the solvent replacement step by ultrafiltration in the present invention may be performed either before or after the surface treatment, but it is preferable to carry out both. In particular, the solvent substitution step after the surface treatment is preferable because it shows a great effect in removing by-products and preventing aggregation during drying.

  Examples of the ultrafiltration method include Research Disclosure No. 1; 10208 (1972), no. 13122 (1975) and no. 16351 (1977) and the like can be referred to. The pressure difference and flow rate that are important as operating conditions can be selected with reference to the characteristic curve described in Haruhiko Oya's “Membrane Utilization Technology Handbook”, Koshobo Publishing (1978), p275. It is necessary to find the optimum condition. There are two methods for replenishing the solvent that is lost due to membrane permeation: a constant volume method in which the solvent is continuously added and a batch method in which the solvent is intermittently added, but the desalting time is relatively short. The formula is preferred.

  As the ultrafiltration unit, a commercially available product can be used. However, in view of detergency and solvent used, those having excellent chemical resistance such as a ceramic membrane and a polysulfone membrane are preferred, and a ceramic membrane is particularly preferred. Further, the molecular weight cut-off serving as an index of the threshold value of the component that can permeate the membrane varies depending on the solvent used, but a molecular weight cut-off in the range of 5000 to 50,000 can be preferably used.

<Drying of inorganic oxide fine particles>
In the present invention, it is preferable to include a step of obtaining a dry powder of the inorganic oxide fine particles after the step of subjecting the inorganic oxide fine particle dispersion to solvent substitution by ultrafiltration. The drying method of the inorganic oxide fine particles according to the present invention is not particularly limited, but freeze drying and spray drying (spray drying) can be preferably used.

  In lyophilization, it is preferable to use a solvent containing at least one of water, cyclohexane, and t-butyl alcohol. These substances have a melting point of from 0 ° C. to a little higher and a high vapor pressure during sublimation, so that they can be easily lyophilized. In the present invention, it is particularly preferable to use t-butyl alcohol.

  In spray drying, it is not preferable to directly heat and dry while containing water, because it causes strong aggregation of particles. Therefore, drying is preferably performed after the solvent replacement step as described above. For example, it is preferable to dry after replacing with an alcohol or ketone solvent.

  Some agglomeration may remain in the powder particles obtained by drying, which can be crushed by various techniques. For example, there are a method of applying shear and impact in the gas phase like a jet mill, and a method of crushing agglomeration with a blade rotating at high speed. It is also possible to dry after dispersing by applying energy such as shear and impact in a non-polar dispersion medium that easily suppresses aggregation during drying.

  As described above, in the present invention, it is preferable to obtain the inorganic particle powder through the freeze-drying step or the spray-drying step, or one of the steps.

《Host resin material》
Next, the host resin material of the present invention will be described.

  In the present invention, a thermoplastic resin or a curable resin is used as the host resin material containing the inorganic oxide fine particles.

(1) Thermoplastic resin First, the thermoplastic resin will be described.

  The thermoplastic resin in which the inorganic oxide fine particles dispersed in the present invention are dispersed is not particularly limited as long as it is a transparent thermoplastic resin material that is generally used as an optical material. However, the processability as an optical element is not limited. In view of the above, it is preferably an acrylic resin, a cyclic olefin resin, a polycarbonate resin, a polyester resin, a polyether resin, a polyamide resin, or a polyimide resin, particularly preferably a cyclic olefin resin, for example, JP-A-2003-73559. The compounds described in the publications can be listed, and preferred compounds are shown in Table 1.

  Moreover, in the thermoplastic resin material which concerns on this invention, it is preferable that a water absorption is 0.2 mass% or less. Examples of the resin having a water absorption of 0.2% by mass or less include polyolefin resin (for example, polyethylene, polypropylene, etc.), fluororesin (for example, polytetrafluoroethylene, Teflon (registered trademark) AF (manufactured by DuPont), Top (made by Asahi Glass Co., Ltd.), cyclic olefin resin (for example, ZEONEX (made by Nippon Zeon), Arton (made by JSR), Apel (made by Mitsui Chemicals), TOPAS (made by Polyplastics), etc.), inden / Styrenic resins, polycarbonates and the like are suitable, but not limited to these. It is also preferable to use other resins compatible with these resins. When two or more kinds of resins are used, the water absorption is considered to be substantially equal to the average value of the water absorption of each resin, and the average water absorption may be 0.2% or less.

  The content of the inorganic oxide fine particles according to the present invention is not particularly limited as long as the effects of the present invention can be exhibited, and can be arbitrarily determined depending on the types of the host resin material and the inorganic oxide fine particles. The content of the inorganic oxide fine particles according to the present invention is preferably such that the volume fraction of the inorganic oxide fine particles with respect to the total volume of the composite material produced is 5% or more and 80% or less, and is 20% or more and 60% or less. It is more preferable that it is 20% or more and 40% 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 oxide fine particles is a, the content is x grams, and the total volume of the composite material produced is Y milliliters. 100 is required.

  The content of the inorganic oxide fine particles can be determined by observing the inorganic oxide fine particle image with a transmission electron microscope (TEM) (information on the composite inorganic oxide fine particle composition can be obtained by local elemental analysis such as EDX), or It can be calculated from the contained mass of a predetermined composition obtained by elemental analysis of ash contained in a given resin composition and the specific gravity of crystals of the composition.

  In the resin material of the present invention, the host resin material made of an organic polymer has a cyclic structure obtained by hydrogenating a copolymer of an α-olefin having 2 to 20 carbon atoms and a cyclic olefin. An olefinic polymer, a compound shown in paragraphs [0032] to [0054] of JP-A-7-145213, or an alicyclic hydrocarbon copolymer comprising a repeating unit having an alicyclic structure. A polymer is preferred. 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.

(2) Curable resin Next, the curable resin according to the present invention will be described.

  The curable resin used in the present invention can be cured by either ultraviolet or electron beam irradiation or heat treatment, and after being mixed with inorganic fine particles in an uncured state, it is transparent by curing. Any resin composition can be used without particular limitation, and examples thereof include epoxy resins, vinyl ester resins, silicone resins, acrylic resins, and allyl ester resins. The curable resin may be an actinic ray curable resin that is cured by being irradiated with ultraviolet rays or electron beams, or may be a thermosetting resin that is cured by heat treatment. Such types of resins can be preferably used.

(2.1) Silicone Resin A silicone resin is a polymer having a main chain of siloxane bonds —Si—O— in which silicon (Si) and oxygen (O) are alternately bonded.

  As the silicone resin, a silicone resin made of a predetermined amount of polyorganosiloxane resin can be used (for example, see JP-A-6-9937).

  The thermosetting polyorganosiloxane resin is not particularly limited as long as it becomes a three-dimensional network structure with a siloxane bond skeleton by a continuous hydrolysis-dehydration condensation reaction by heating, and is generally cured by heating at a high temperature for a long time. Once cured, it is difficult to re-soften by heating.

  Such a polyorganosiloxane resin includes the following general formula (A) as a structural unit, and the shape thereof may be any of a chain, a ring, and a network.

Formula (A) ((R1) (R2) SiO) n
In the general formula (A), R1 and R2 represent the same or different substituted or unsubstituted monovalent hydrocarbon groups. Specifically, as R1 and R2, alkyl groups such as methyl group, ethyl group, propyl group, and butyl group, alkenyl groups such as vinyl group and allyl group, aryl groups such as phenyl group and tolyl group, cyclohexyl group, cyclohexane A cycloalkyl group such as an octyl group, or a group in which a hydrogen atom bonded to a carbon atom of these groups is substituted with a halogen atom, a cyano group, an amino group, or the like, such as a chloromethyl group, 3,3,3-trifluoropropyl Group, cyanomethyl group, γ-aminopropyl group, N- (β-aminoethyl) -γ-aminopropyl group and the like are exemplified. R1 and R2 may be a group selected from a hydroxyl group and an alkoxy group. In the general formula (A), n represents an integer of 50 or more.

  The polyorganosiloxane resin is usually used after being dissolved in a hydrocarbon solvent such as toluene, xylene or petroleum solvent, or a mixture of these with a polar solvent. Moreover, you may mix | blend and use what differs in a composition in the range which mutually melt | dissolves.

  The method for producing the polyorganosiloxane resin is not particularly limited, and any known method can be used. For example, it can be obtained by hydrolysis or alcoholysis of one or a mixture of two or more organohalogenosilanes, and polyorganosiloxane resins generally contain hydrolyzable groups such as silanol groups or alkoxy groups. 1 to 10% by mass in terms of a silanol group.

  These reactions are generally performed in the presence of a solvent capable of melting the organohalogenosilane. It can also be obtained by a method of synthesizing a block copolymer by cohydrolyzing a linear polyorganosiloxane having a hydroxyl group, an alkoxy group or a halogen atom at the molecular chain terminal with an organotrichlorosilane. The polyorganosiloxane resin thus obtained generally contains the remaining HCl, but in the composition of the present embodiment, the storage stability is good, so that the one having 10 ppm or less, preferably 1 ppm or less is used. Is good.

(2.2) Epoxy resin An alicyclic epoxy resin such as 3,4-epoxycyclohexylmethyl-3 ′, 4′-cyclohexylcarboxylate (see International Publication No. 2004/031257 pamphlet) can be used. An epoxy resin containing a spiro ring or a chain aliphatic epoxy resin can also be used.

(2.3) Curable resin having an adamantane skeleton 2-alkyl-2-adamantyl (meth) acrylate (see JP 2002-193883 A), 3,3′-dialkoxycarbonyl-1,1′-biadamantane (See JP 2001-253835 A), 1,1′-biadamantane compound (see US Pat. No. 3,342,880), tetraadamantane (see JP 2006-169177), 2-alkyl A curable resin having an adamantane skeleton having no aromatic ring such as 2-hydroxyadamantane, 2-alkyleneadamantane, and di-t-butyl 1,3-adamantanedicarboxylate (see JP-A-2001-322950), bis ( Hydroxyphenyl) adamantanes and bis (glycidyloxyphenyl) adaman Tan (see JP-A-11-35522 and JP-A-10-130371) can be used.

(2.4) Resin containing allyl ester compound Bromine-containing (meth) allyl ester not containing an aromatic ring (see JP 2003-66201 A), allyl (meth) acrylate (see JP 5-286896 A) , Allyl ester resins (see JP-A-5-286896 and JP-A-2003-66201), copolymer compounds of acrylic esters and epoxy group-containing unsaturated compounds (see JP-A-2003-128725), acrylate compounds (Refer to Unexamined-Japanese-Patent No. 2003-147072), an acrylic ester compound (refer to Unexamined-Japanese-Patent No. 2005-2064), etc. can be used preferably.

"Additive"
Various additives (also referred to as compounding agents) can be added as necessary during the preparation of the resin material of the present invention and in the molding process of the resin composition. 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 resin material 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 singly 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 host resin material according to the present invention. Preferably it is 0.001-5 mass parts with respect to 100 mass parts, 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), the Mn in terms of polystyrene measured by GPC (gel permeation chromatography) using tetrahydrofuran (THF) as a solvent is 1,000 to 10,000. A thing of 2,000-5,000 is more preferable, and a thing of 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 excellent in processing stability, low gas generation and transparency can be obtained by setting the HALS Mn in 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 the like in which a plurality of piperidine rings are bonded via a triazine skeleton. 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, Mixing of 6,6-pentamethyl-4-piperidinol with 3,9-bis (2-hydroxy-1,1-dimethylethyl) -2,4,8,10-tetraoxaspiro [5,5] undecane Such 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 resin material of the present invention is preferably 0.01 to 20 parts by mass, more preferably 0.02 to 15 parts by mass, and particularly preferably 0.05 to 10 parts by mass with respect to 100 parts by mass of the host resin material. Part 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 and the transparency of the lens is lowered.

  Further, by blending the host resin material of the present invention with a compound having the lowest glass transition temperature of 30 ° C. or less, it does not deteriorate various properties such as transparency, heat resistance and mechanical strength for a long time. Can prevent cloudiness in high temperature and high humidity environment.

<Method of mixing host resin material and inorganic oxide fine particles>
The optical resin material of the present invention comprises the host resin material and the inorganic oxide fine particles as described above, but the mixing method is not particularly limited.

  When a thermoplastic resin is used as the host resin material, a method of forming a composite by polymerizing a thermoplastic resin in the presence of inorganic fine particles, a method of forming and combining inorganic fine particles in the presence of a thermoplastic resin, inorganic fine particles A dispersion in a liquid that becomes a solvent for the thermoplastic resin, and then compounding by removing the solvent, preparing inorganic fine particles and the thermoplastic resin separately, melting and kneading, melting in a state containing the solvent It can be produced by any method such as a method of compounding by kneading. Various additives may be added at any step of the compounding process, but the addition timing that does not hinder the compounding can be selected.

  Among these, the method of preparing the inorganic fine particles and the thermoplastic resin separately and combining them by melt-kneading is preferably used because it is simple and can suppress the manufacturing cost. As an apparatus which can be used for melt kneading, for example, a closed kneading apparatus such as a lab plast mill, a Brabender, a Banbury mixer, a kneader, a roll, or a batch kneading apparatus can be given. Moreover, it can also manufacture using a continuous melt-kneading apparatus like a single screw extruder, a twin screw extruder, etc.

  In the method for producing an optical organic-inorganic composite material of the present invention, when melt kneading is used, the thermoplastic resin and the inorganic fine particles may be added and kneaded all at once, or may be divided and added in stages. . In this case, in a melt-kneading apparatus such as an extruder, it is possible to add the components to be added step by step from the middle of the cylinder. In addition, after kneading in advance, when components other than thermoplastic resin that have not been added in advance are added and further melt-kneaded, these may be added all at once and kneaded, or added in stages. And may be kneaded. The method of adding in a divided manner or the method of adding one component in several batches can be adopted, the method of adding one component at a time and the method of adding different components in stages can also be adopted, both of which are combined The method is fine.

  In the case of compounding by melt kneading, the inorganic fine particles can be added in a powder or agglomerated state. Or it is also possible to add in the state disperse | distributed in the liquid. When adding in the state disperse | distributed in the liquid, it is preferable to perform devolatilization after kneading | mixing.

  In the optical resin material of the present invention, when a curable resin is used as the host resin material, a monomer of the curable resin, a curing agent, a curing accelerator, and various additives are mixed with inorganic fine particles appropriately subjected to surface treatment, It can be obtained by curing by either ultraviolet ray or electron beam irradiation or heat treatment.

  In the optical resin material of the present invention, the content of the inorganic fine particles in the optical resin material is not particularly limited as long as the effect of the present invention can be exhibited, and is arbitrarily determined depending on the type of the resin and the inorganic fine particles. Can do.

  However, when the content of the inorganic fine particles is small, the effect of improving the temperature dependence of the optical properties, which is the object of the present invention, may be reduced, so the volume of the inorganic fine particles in the optical organic-inorganic composite material The fraction Φ is preferably 20% or more, and more preferably 30% or more.

  On the other hand, when the content of the inorganic fine particles is high, it becomes difficult to add the inorganic fine particles to the resin, or the optical organic / inorganic composite material becomes hard and kneading or molding becomes difficult. Therefore, the volume fraction Φ of the inorganic fine particles in the optical organic-inorganic composite material is preferably 60% or less, and preferably 50% or less. More preferred.

  The volume fraction Φ of the inorganic fine particles in the optical resin material is calculated by Φ = (total volume of the inorganic fine particles in the optical resin material) / (volume of the optical resin material) × 100. is there.

  The degree of mixing of the resin and the inorganic fine particles in the optical resin material is not particularly limited, but it is desirable that the resin is uniformly mixed in order to achieve the effect of the present invention more efficiently. When the degree of mixing is insufficient, there is a concern that the particle size distribution of the inorganic fine particles in the composite material may become difficult to satisfy the conditions defined in the present invention. Since the particle size distribution of the inorganic fine particles in the thermoplastic resin composition is greatly influenced by the production method, the optimum method should be selected in consideration of the characteristics of the thermoplastic resin and inorganic fine particles used. is important.

  Various molding materials can be obtained by molding the optical resin material as described above, but the molding method is not particularly limited. When a thermoplastic resin is used as the resin, a melt molding method is preferably used in order to obtain a molded product having excellent characteristics such as low birefringence, mechanical strength, and dimensional accuracy, and a commercially available press molding is used as the melt molding method. , Commercially available extrusion molding, and commercially available injection molding. Among these, injection molding is preferably used from the viewpoint of moldability and productivity.

  On the other hand, when a curable resin is used as the resin, a mixture of a resin composition such as a curable resin monomer and a curing agent and inorganic fine particles is used. The resin composition is filled into a predetermined shape mold or the like, or applied onto a substrate and then cured by irradiation with ultraviolet rays and an electron beam. On the other hand, when the curable resin is a thermosetting resin, It can be cured by compression molding, transfer molding, injection molding or the like.

<Characteristics of optical resin materials>
Furthermore, the optical resin material of the present invention is characterized by a small temperature change rate (dn / dT) of refractive index.

  Here, dn / dT, which is an index of the rate of change of the refractive index n with respect to the temperature T, means that the refractive index (n) of the optical resin material changes at a rate of dn / dT with respect to the change of the temperature (T). Is shown. The value of dn / dT can be obtained by measuring the refractive index of the optical 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 optical resin material from, for example, ellipsometry, spectral reflectance method, optical waveguide method, Abbe method, minimum deviation method, and the like.

In the optical resin material of the present invention, | dn / dT |, which is the absolute value of dn / dT, is preferably 0 or more and 9.0 × 10 ⁻⁵ or less, and | dn / dT | is 0 or more. 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 optical resin material of the present invention preferably has transparency in the visible region wavelength. The transparency of the optical resin material of the present invention is generally 60% or more, preferably 70% or more, more preferably 80% or more, and most preferably 90% when the light transmittance in the visible region wavelength is 3 mm. The above is desirable. Such measurement is performed, for example, by a test according to the 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 optical resin material of the present invention is determined by the combination of the host resin material and the inorganic particles, but it is usually made higher than the refractive index of the resin by selecting inorganic particles having a higher refractive index than the resin. Is preferred. Specifically, the range of about 1.45 to 2.0 is preferable, and more preferably 1.49 to 1.7.

  The optical resin material of the present invention is a material composition that has a low refractive index temperature dependency and high transparency, is optically excellent, and is extremely excellent in molding processability. This optical resin material having both excellent optical characteristics and moldability is a characteristic that has not been achieved with the materials disclosed so far, and consists of a specific resin and specific inorganic fine particles. However, it is thought that this contributes to this characteristic.

<Application field>
The molded article of the optical resin material of the present invention can be applied to an optical element or the like. The molded product can be used in various forms such as spherical, rod-shaped, plate-shaped, cylindrical, cylindrical, tube-shaped, fibrous, film or sheet-shaped, and has low birefringence, transparency, machine Since it is excellent in strength, heat resistance and low water absorption, application to various optical elements is suitable.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

  As shown in FIG. 1, an imaging apparatus 100 as an electronic module has a circuit board 1 on which electronic components constituting an electronic circuit of a mobile information terminal device such as a mobile phone are mounted. Module 2 is mounted. The imaging module 2 is a small board mounting camera in which a CCD image sensor and a lens are combined. In a completed state in which the circuit board 1 on which electronic components are mounted is assembled in the cover case 3, the imaging provided in the cover case 3 is performed. The image to be imaged can be captured through the opening 4 for use. In FIG. 1, illustration of electronic components other than the electronic components of the imaging module 2 is omitted.

  As shown in FIG. 2, the imaging module 2 is composed of a board module 5 (see FIG. 3A) and a lens module 6 (see FIG. 3A). By mounting the board module 5 on the circuit board 1, The entire imaging module 2 is mounted on the circuit board 1. The substrate module 5 is a light receiving module in which a CCD image sensor 11, which is an electronic component for imaging, is mounted on a sub-substrate 10, and the upper surface of the CCD image sensor 11 is sealed with a resin 12.

  On the upper surface of the CCD image sensor 11, a light receiving portion (not shown) in which a large number of pixels that perform photoelectric conversion are arranged in a grid pattern is formed, and an optical image is formed on the light receiving portion to store each pixel. The charged charges are output as an image signal. The sub-board 10 is mounted on the circuit board 1 by the conductive material 18, thereby fixing the sub-board 10 to the circuit board 1, and connecting electrodes (not shown) of the sub-board 10 and circuit electrodes on the upper surface of the circuit board 1. (Not shown) is electrically connected.

  The lens module 6 includes a lens case 15 that supports the lens 16. A lens 16 is held at the upper part of the lens case 15, and the upper part of the lens case 15 is a holder portion 15 a for holding the lens 16. A lower portion of the lens case 15 is inserted into a mounting hole 10 a provided in the sub-board 10 and serves as a mounting portion 15 b that fixes the lens module 6 to the sub-board 10. For this fixing, a method of pressing and fixing the mounting portion 15b into the mounting hole 10a, a method of bonding with an adhesive, or the like is used.

  The lens 16 is an image pickup element (optical element) used in the image pickup optical system, and is composed of a composite material. The lens 16 is also composed of only a curable resin as a base material, and a film made of an infrared absorbing / reflecting agent or an ultraviolet absorbing / reflecting agent is formed on the surface of the base material by a known method such as a vapor deposition method. It is good also as a structure.

  Next, a method for manufacturing the imaging device 100 as an electronic module will be described with reference to FIG.

  First, the substrate module 5 and the lens module 6 are assembled. As shown in FIG. 3A, the lens case until the lower end of the collar member 17 mounted in the lens case 15 comes into contact with the upper surface of the sub substrate 10. The 15 mounting portions 15 b are inserted and fixed in the mounting holes 10 a of the sub-board 10 to form the imaging module 2.

  Thereafter, as shown in FIG. 3B, the imaging module 2 and other electronic components are placed at a predetermined mounting position of the circuit board 1 on which the conductive material 18 has been applied (potted) in advance. Thereafter, as shown in FIG. 3C, the circuit board 1 on which the imaging module 2 and other electronic components are placed is transferred to a reflow furnace (not shown) by a belt conveyor or the like, and the circuit board 1 is subjected to reflow processing. Heating at a temperature of about 180 to 270 ° C. As a result, the conductive material 18 melts and the imaging module 2 is mounted on the circuit board 1 together with other electronic components.

  In the present embodiment described above, the lens 16 of the imaging module 2 is composed of a composite material, and since the composite material contains an infrared absorption / reflection agent and an ultraviolet absorption / reflection agent, the lens 16 is heated at a high temperature called a reflow process. Even if it is subjected to treatment (about 180 to 270 ° C.), deformation can be suppressed (see the following examples).

  The optical element 1 is obtained by the above manufacturing method, and is applied to the following optical component, for example.

  For 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; , MO (rewritable optical disc; magneto-optical disc), MD (mini disc), optical disc pick-up lens such as DVD (digital video disc); laser scanning system lens such as laser beam printer fθ lens, sensor lens; Examples include prism lenses for camera viewfinder systems.

  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; 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) 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.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated concretely, this invention is not limited to these.

Example 1
(Preparation of inorganic oxide fine particle dispersion A)
A solution prepared by adding 50 ml of pure water, 390 ml of special grade ethanol (manufactured by Kanto Chemical), and 22 ml of 28% ammonia (manufactured by Kanto Chemical) to 7.2 g of alumina (Alumina C, Nippon Aerosil Co., Ltd., primary particle diameter 13 nm) Then, 0.72 g of tetraethoxysilane (LS-2430 manufactured by Shin-Etsu Chemical Co., Ltd.) was added to this solution, and the solution was used with Ultra Apex Mill UAM-015 (manufactured by Kotobuki Industries Co., Ltd.) using 0.05 mm beads. And dispersed for 1 hour at a peripheral speed of 6 m / sec. Thereafter, 0.72 g of tetraethoxysilane (LS-2430, manufactured by Shin-Etsu Chemical Co., Ltd.) was further added to the dispersion and stirred for 1 hour in the same manner as described above.

  Thereafter, 18.16 g of tetraethoxysilane (LS-2430 manufactured by Shin-Etsu Chemical Co., Ltd.) was diluted with a mixed solution of 40 ml of ethanol and 5 ml of pure water, and the diluted solution was added dropwise to the dispersion obtained in the above dispersion step over 10 minutes. . The solution was stirred at room temperature for 20 hours.

  The obtained dispersion was an ethanol / water mixed solvent dispersion of composite oxide fine particles in which a silica layer was formed on the surface of alumina, and this was designated as inorganic oxide fine particle dispersion A.

<Preparation of optical resin material 1>
The inorganic oxide fine particle dispersion A was centrifuged to precipitate the particles. The particles were dried under reduced pressure at 80 ° C. for 24 hours, and 10% by mass of silane coupling agent hexamethyldisilazane (HMDS) was further added to the particles, followed by heating to 150 ° C. with stirring and surface treatment for 2 hours. went. Then, it dried under reduced pressure at 80 degreeC for 24 hours, and obtained the inorganic fine particle powder.

  1-adamantyl methacrylate prepared according to JP-A-2002-193883 as a thermosetting monomer, 0.2 parts by mass of a phenolic antioxidant (Irganox 1010, manufactured by Ciba Japan) as an antioxidant, and a radical polymerization initiator 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane (manufactured by NOF Corporation, Perhexa 3M-95) 0.01 parts by mass, so that the inorganic fine particles are 20% by volume, The mixture was kneaded with a twin-screw kneader (Toyo Seiki Seisakusho Lab Plast Mill), poured into a mold and polymerized at 80 ° C. for 4 hours to prepare a test plate having a thickness of 3 mm.

<Preparation of optical resin material 2>
The inorganic oxide fine particle dispersion A is dried at 200 ° C. using a spray drying apparatus, and then N ₂ gas, ammonia, and HMDS are flowed as reaction gases in a surface treatment tank maintained at 200 ° C. for surface treatment. went. Using the obtained inorganic fine particle powder, a test plate having a thickness of 3 mm was prepared by kneading and molding with 1-adamantyl methacrylate resin in the same manner as the production method of the optical resin material 1.

<Preparation of optical resin material 3>
The inorganic oxide fine particle dispersion A was circulated through a ceramic UF filter manufactured by NGK with a molecular weight cut off of 20,000 while applying a pressure of 0.5 MPa, and ultrafiltration was performed until the liquid volume became 1/5. Thereafter, the same amount of acetonitrile as the amount of the discharged solvent was added, and the ultrafiltration operation until the liquid amount became 1/5 was repeated four times to prepare an inorganic oxide fine particle dispersion in which the solvent was substituted with acetonitrile. .

  To this acetonitrile dispersion, 50% by mass of HMDS with respect to the amount of inorganic oxide fine particles was added, and surface treatment was performed at 80 ° C. for 2 hours to obtain an acetonitrile dispersion of surface-treated inorganic oxide fine particles. This was designated as inorganic oxide fine particle dispersion B.

  The inorganic oxide fine particle dispersion B was subjected to solvent replacement by ultrafiltration using a ceramic UF filter having a molecular weight cut off of 20,000 and using tert-butyl alcohol in place of acetonitrile in the same manner as described above.

  Further, the resulting tert-butyl alcohol dispersion of the surface-treated inorganic oxide fine particles was freeze-dried to obtain inorganic fine particle powder, which was kneaded and molded with 1-adamantyl methacrylate resin in the same manner as the production method of the optical resin material 1. Thus, a test plate having a thickness of 3 mm was produced.

<Preparation of optical resin material 4>
The inorganic oxide fine particle dispersion B was subjected to solvent substitution by ultrafiltration using a ceramic UF filter with a molecular weight cut off of 20,000 and using ethanol instead of acetonitrile in the same manner as described above. Further, the obtained ethanol dispersion of the surface-treated inorganic oxide fine particles was poured into a stainless steel vat and dried in an oven at 150 ° C. for 2 hours to form inorganic fine particle powders. Similarly, a test plate having a thickness of 3 mm was prepared by kneading and molding with 1-adamantyl methacrylate resin.

<Preparation of optical resin material 5>
The ethanol dispersion of the surface-treated inorganic oxide fine particles obtained in the same manner as in the production of the optical resin material 4 is dried at 200 ° C. using a spray drying apparatus to form inorganic fine particle powders. The test plate having a thickness of 3 mm was prepared by kneading and molding with 1-adamantyl methacrylate resin in the same manner as in the above preparation method.

<Preparation of optical resin material 6>
A biaxial kneader at 200 ° C. was used so that the inorganic fine particle powder obtained in the same manner as the production of the optical resin material 5 was 20% by volume with respect to APEL5014 manufactured by Mitsui Chemicals, which is a thermoplastic resin. Then, the mixture was poured into a mold to prepare a test plate having a thickness of 3 mm.

<Preparation of optical resin material 7>
50 mass% HMDS is added to the amount of silica fine particles to origano silica sol MEK-ST (manufactured by Nissan Chemical Co., Ltd.), which is a MEK dispersion of silica fine particles having an average particle diameter of 15 nm, and surface treatment is performed at 80 ° C. for 2 hours. And a surface-treated silica fine particle MEK dispersion was obtained. The obtained dispersion was subjected to ethanol solvent substitution by ultrafiltration in the same manner as in the production of the optical resin material 5 and was spray-dried to form an inorganic fine particle powder, which was kneaded and molded with 1-adamantyl methacrylate resin to a thickness of 3 mm. A test plate was prepared.

<Preparation of optical resin material 8>
Origano silica sol MEK-ST is dried at 200 ° C. using a spray dryer to form inorganic fine particle powder. Further, 10% by mass of silane coupling agent hexamethyldisilazane (HMDS) is added to the particles, The surface treatment was performed for 2 hours by heating to 150 ° C. with stirring. Then, it dried under reduced pressure at 80 degreeC for 24 hours, and obtained the surface-treated silica fine particle powder. Thereafter, in the same manner as the production method of the optical resin material 1, a test plate having a thickness of 3 mm was produced by kneading and molding with 1-adamantyl methacrylate resin.

<Preparation of optical resin material 9>
Origano silica sol MEK-ST is poured into a stainless steel vat and dried in an oven at 150 ° C. for 2 hours to form an inorganic fine particle powder. Further, silane coupling agent hexamethyldisilazane (HMDS) is added to the particles. 10 mass% was added, and it heated to 150 degreeC, stirring, and surface-treated for 2 hours. Then, it dried under reduced pressure at 80 degreeC for 24 hours, and obtained the surface-treated silica fine particle powder. Thereafter, in the same manner as the production method of the optical resin material 1, a test plate having a thickness of 3 mm was produced by kneading and molding with 1-adamantyl methacrylate resin.

  Table 2 shows details of the optical resin materials 1 to 9 produced as described above.

<Evaluation>
<Measurement of average dispersed particle size>
The average dispersed particle diameter is the diameter when the dispersion is appropriately diluted, a transmission electron micrograph of the slice is taken, and the single particles (including the single particles constituting the aggregate) are converted to spheres of the same volume. The average value was obtained.

<Evaluation of refractive index>
By using an automatic refractometer KPR-200 manufactured by Kalnew Optical Industry Co., Ltd., a test plate of optical resin materials 1-9, changing the refractive index at a wavelength of 588 nm and changing the sample temperature from 10 ° C. to 60 ° C. It was measured. 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 3.

<Measurement of transmittance>
The optical transmittance of the optical resin materials 1 to 9 was measured using a TURBIDITY METER T-2600DA manufactured by Tokyo Denshoku Co., Ltd., in accordance with ASTM D1003. 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 (%). .

  Further, as a substitute test for reflow resistance, each test plate was placed in a furnace at 260 ° C., taken out after 3 minutes, and the light transmittance of the sample was measured. This was designated as transmittance C (%).

  In addition, when the measured light transmittance was 80% 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 3.

  As is apparent from the results shown in Table 3, it can be seen that the optical resin material produced by the production method of the present invention has a low temperature dependency of the refractive index and high transparency relative to the comparative example. 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.

It is a schematic perspective view of the imaging device used by preferable embodiment of this invention. 1 is an enlarged schematic cross-sectional view of a part of an imaging apparatus used in a preferred embodiment of the present invention. It is drawing for demonstrating schematically the manufacturing method of the imaging device in preferable embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Imaging device 1 Circuit board 2 Imaging module 3 Cover case 4 Imaging opening 5 Substrate module 6 Lens module 10 Sub board | substrate 10a Mounting hole 11 CCD image sensor 12 Resin 15 Lens case 15a Holder part 15b Mounting part 16 Lens 17 Color member 18 Conductivity Material

Claims (7)

A method for producing an optical resin material containing inorganic oxide fine particles having an average particle diameter of 1 nm or more and 50 nm or less in a host resin material, wherein the dispersion of the inorganic oxide fine particles is solvent-substituted by ultrafiltration A method for producing an optical resin material, comprising: a step; and a step of subjecting the inorganic oxide fine particles to a surface hydrophobization treatment in a solvent. 2. The optical resin material production according to claim 1, wherein the step of subjecting the inorganic oxide fine particle dispersion to solvent substitution by ultrafiltration is performed after the surface hydrophobization treatment step of the inorganic oxide fine particles. Method. 3. The optical resin according to claim 1, further comprising a step of obtaining a dry powder of the inorganic oxide fine particles after the step of solvent substitution of the dispersion of the inorganic oxide fine particles by ultrafiltration. Material manufacturing method. The method for producing an optical resin material according to any one of claims 1 to 3, wherein the inorganic oxide fine particles are composite oxide fine particles composed of silicon and another metal element. The method for producing an optical resin material according to claim 1, wherein the surface hydrophobization treatment of the inorganic oxide fine particles is performed using a silicon compound. An optical resin material manufactured by the manufacturing method according to claim 1. An optical element molded using the optical resin material according to claim 6.

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