JP2008231400A - Resin composition for optical element and curable resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin composition for optical elements, which is excellent in light resistance and heat resistance and can maintain optical transparency from the near ultraviolet region to the visible wavelength region over a long period, and to provide a curable resin composition used for the same. <P>SOLUTION: This resin composition for optical elements is characterized by condensation-reacting two kinds of metal oxides with an organopolysiloxane without adding a reaction catalyst. It is desirable that two or more kinds of metal alkoxides include silicon alkoxides and titanium alkoxides. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a resin composition for optical elements used for light-emitting diode elements and the like, and a curable resin composition used for the same.

  A light emitting diode (LED) element is usually covered with a sealing material in order to protect the LED element and change the color. And in order to take out the light emitted from the LED element efficiently, high optical transparency is requested | required of this sealing material.

Conventionally, the resin used for this sealing material is generally an epoxy resin.
However, when a blue LED element or an ultraviolet LED element is used as the light emitting element, the near-ultraviolet light emitted from the blue LED element or the ultraviolet LED element causes yellowing of the epoxy resin sealing material in the vicinity of the light emitting element, There was a problem of heat deterioration due to heat generation.

  In addition, a silicone resin encapsulant is being investigated as a heat-resistant encapsulant that does not cause yellowing due to near-ultraviolet light or ultraviolet light, but a silicone resin made of dimethylsiloxane has a low refractive index. For example, a method of using a silicone resin having a phenyl group in the molecule (for example, refer to Patent Document 1) or including a metal oxide in a siloxane-based condensate in order to set the refractive index to 1.5 or more. (See, for example, Patent Document 2).

JP 2006-63092 A JP 2006-299251 A

  However, such a method has a problem that it is difficult to maintain optical transparency over a long period in the near-ultraviolet to visible wavelength region.

The object of the present invention is to solve all the above-mentioned problems.
That is, an object of the present invention is to provide an optical element resin composition that is excellent in light resistance and heat resistance and can maintain optical transparency over a long period in the near ultraviolet to visible wavelength region, and a curable resin composition used therefor Is to provide.

(1) The present invention relates to a resin composition for an optical element obtained by subjecting two or more metal alkoxides and an organopolysiloxane to a condensation reaction without adding a reaction catalyst.

(2) The above-described two or more metal alkoxides preferably include silicon alkoxide and titanium alkoxide.

(3) Further, in the above-described two inventions (1) or (2), light transmittance at 350 to 800 nm after irradiation with light of wavelength 365 nm and light amount of 3000 mW / cm ² for 24 hours in an atmosphere of 60 ° C. However, it is related with the resin composition for optical elements which is 80% or more.

(4) In the above-described three inventions (1), (2), or (3), the optical transmittance at 350 to 800 nm after being left in an atmosphere at 200 ° C. for 200 hours is 85% or more. The present invention relates to a resin composition for an element.

(5) Furthermore, the curable resin composition used for the optical element resin composition according to (1), (2), (3) or (4), which is the four inventions described above, comprising a plurality of metal alkoxides and A curable resin composition containing an organopolysiloxane.

  According to the present invention, there are provided a resin composition for an optical element that is excellent in light resistance and heat resistance and can maintain optical transparency over a long period in the near ultraviolet to visible wavelength region, and a curable resin composition used therefor. can do.

Hereinafter, the present invention will be described in detail.
As described above, since the silicone-based condensate has high transparency and heat resistance, it is effective as a material for optical elements.
On the other hand, an inorganic / organic hybrid in which an inorganic component and an organic component are chemically bonded at a molecular level is synthesized by a sol-gel method from a metal alkoxide, and is attracting attention as a new material having both inorganic and organic characteristics.

  However, even in the above method, since a metal catalyst such as a tin-based catalyst is used in the final condensation reaction stage, high transparency cannot be obtained.

  As a result of intensive studies by the present inventors on the above-mentioned problems, a reaction catalyst can be obtained by using two or more metal alkoxides in the hybridization of the inorganic component and the organic component using metal alkoxide and organopolysiloxane. It has been found that the hydrolysis reaction proceeds easily without using it, and the hydrolyzed component can be subjected to a condensation reaction without using a reaction catalyst such as a metal catalyst in the subsequent condensation reaction step.

That is, in the sol-gel method using a metal alkoxide or the like, usually, a raw material such as a metal alkoxide is first hydrolyzed under an acidic or basic catalyst.
However, when two or more metal alkoxides are used, the raw material components can be hydrolyzed without using an acidic or basic catalyst.

  In addition, a metal catalyst such as tin is generally used for the condensation reaction of the hydrolyzate. However, the hydrolyzate obtained by reacting two or more metal alkoxides may be a reaction catalyst such as a metal catalyst. Thus, the condensation reaction can be progressed only by heating without using the above, and the desired cured product (resin composition for optical elements) can be obtained.

And in the inorganic-organic hybrid obtained by the above, since the polycondensate of organopolysiloxane became main, it turned out that high transparency is obtained.
Furthermore, in addition to the above-mentioned excellent optical characteristics, it has been found that the light resistance and heat resistance are also excellent, and the excellent optical characteristics can be maintained even after light irradiation or heating.

Hereinafter, the resin composition for an optical element of the present invention will be described together with its production method.
(Metal alkoxide)
The metal or metalloid forming the metal alkoxide used in the present invention includes boron, aluminum, silicon, titanium, vanadium, manganese, iron, cobalt, zinc, germanium, yttrium, zirconium, niobium, cadmium, tantalum and tungsten. And metal or metalloid capable of forming an alkoxide such as.

  Further, the type of alkoxide is not particularly limited, and examples thereof include methoxide, ethoxide, propoxide, isopropoxide, butoxide and the like. Furthermore, a part of the alkoxy group is β-diketone, β-ketoester and the like. It may be a substituted alkoxide derivative.

  In the present invention, a plurality (two or more) of metal alkoxides are used, and it is preferable that the plurality of metal alkoxides include silicon alkoxide and titanium alkoxide. It is also preferable to use zirconium alkoxide.

  Silicon alkoxides are cheaper and easier to obtain than titanium alkoxides and zirconium alkoxides, and are excellent in workability because of their mild reactions. On the other hand, titanium alkoxide and zirconium alkoxide are more likely to undergo reactions such as hydrolysis and condensation than silicon alkoxide, and it is expected that the hydrolysis reaction described below can proceed without using an acid.

  When a metal alkoxide containing these and an organopolysiloxane are reacted in the presence of water, the alkoxy group of the metal alkoxide is substituted with a hydroxyl group, and the hydroxyl group is dehydrated and condensed with, for example, a silanol group at the end of the organopolymethylsiloxane. By causing the reaction, an inorganic / organic hybrid composed of an inorganic component derived from metal alkoxide and organopolymethylsiloxane is formed.

  Specific examples of the silicon alkoxide include tetramethoxysilane, tetraethoxysilane, tetra-iso-propoxysilane, tetra-n-propoxysilane, tetra-n-butoxysilane, tetra-sec-butoxysilane, tetra-tert- Butoxysilane, tetrapentaethoxysilane, tetrapenta-iso-propoxysilane, tetrapenta-n-propoxysilane, tetrapenta-n-butoxysilane, tetrapenta-sec-butoxysilane, tetrapenta-tert-butoxysilane, methyltrimethoxysilane, methyltrimethoxysilane Ethoxysilane, methyltripropoxysilane, methyltributoxysilane, dimethylmethoxysilane, dimethyldimethoxysilane, dimethylethoxysilane, dimethyldiethoxysilane, di Chill propoxysilane, dimethyl-butoxy silane, methyl dimethoxy silane, methyl diethoxy silane, hexyl trimethoxy silane and the like. These may be used individually by 1 type and may be used in combination of 2 or more type.

  Moreover, as a titanium alkoxide and a zirconium alkoxide, the titanium tetraalkoxide and zirconium alkoxide whose carbon number of an alkoxyl group is 1-10 are used preferably. In order to suppress reactivity and improve workability, titanium tetraalkoxide or zirconium tetraalkoxide having 3 to 8 carbon atoms in the alkoxy group is more preferable. In this titanium tetraalkoxide, the four alkoxyl groups may be the same or different, but the same one is preferably used from the viewpoint of availability.

  Examples of the titanium tetraalkoxide include titanium tetramethoxide, titanium tetraethoxide, titanium tetra-n-propoxide, titanium tetraisopropoxide, titanium tetra-n-butoxide, titanium tetraisobutoxide, titanium tetra-sec- Butoxide, Titanium tetra-tert-butoxide, Titanium tetra-2-ethylhexoxide, Zirconium tetramethoxide, Zirconium tetraethoxide, Zirconium tetra-n-propoxide, Zirconium tetraisopropoxide, Zirconium tetra-n-butoxide, Zirconium tetraiso Butoxide, zirconium tetra-sec-butoxide, zirconium tetra-tert-butoxide, zirconium tetra-2-ethyl hetoxide, and zirconium tetra- ert- pentyl oxide, and the like.

  These including silicon alkoxide may be used individually by 1 type, and may be used in combination of 2 or more type.

  As will be described later, in order to obtain a resin composition for an optical element, there are a case where two liquids each containing a silicon alkoxide and a titanium alkoxide are mixed, and a case where they are reacted in a single liquid containing both. When is mixed, it is desirable that the mass ratio (A / B) of the silicon alkoxide amount A and the titanium alkoxide amount B is in the range of 40/1 to 100/1.

  The content of the plurality of metal alkoxides including silicon alkoxide and titanium alkoxide in the reaction system after mixing is preferably in the range of 1 to 40% by mass, and in the range of 5 to 15% by mass. More preferred.

(Organopolysiloxane)
Examples of the organopolysiloxane used in the present invention include polydimethyl having a functional group capable of reacting with a functional group of a silane compound, metal and / or metalloid alkoxide at one or both ends, such as silanol-modified polydimethylsiloxane. Siloxane (PDMS) or the like can be used.

  As said organopolysiloxane, it is desirable to use what has the weight average molecular weight of polystyrene conversion measured by the gel permeation chromatography in the range of 400-80000. If the weight average molecular weight of the organopolysiloxane exceeds 80,000, the viscosity of the sol solution may become too high and workability may deteriorate. If the weight average molecular weight is less than 400, the resin composition for optical elements is low. The generation of molecular siloxane is increased, and as a result, the insulation failure of the electrical contact is likely to occur.

  The weight average molecular weight of the organopolysiloxane is more preferably in the range of 4000 to 60000, and still more preferably in the range of 10000 to 40000.

  The functional group of polydimethylsiloxane (PDMS) having the functional group, the functional group capable of reacting with the functional group of the PDMS is a functional group having active hydrogen, or a functional group potentially having active hydrogen. It is.

  Examples of the functional group include functional groups 1 to 13 shown below. In the following formula, R and R ′ each independently represents a substituted or unsubstituted alkylene group or alkyl group.

但し、上記において、Ｘは−ＯＣＨ_３、−ＯＣ_２Ｈ_５等のアルコキシル基、のいずれかを表す。

However, in the above, X represents -OCH _3, alkoxyl groups such as _-OC 2 _{H 5,} one of the.

  Organopolysiloxane such as PDMS having such a functional group easily reacts smoothly with the metal alkoxide. The organopolysiloxane is preferably heat-treated in order to remove excess water and low molecular weight components. If moisture removal is performed, when a metal alkoxide is added to the organopolysiloxane solution described later, hydrolysis of the metal alkoxide due to residual moisture can be prevented, and a resin composition for optical elements (organic / organic) due to residual low molecular weight components remains. It is possible to effectively eliminate problems such as surface stickiness of inorganic hybrid) and deterioration of mechanical strength.

  The content of the organopolysiloxane in the condensation reaction system is preferably in the range of 40 to 95% by mass, and more preferably in the range of 70 to 85% by mass.

The resin composition for an optical element of the present invention can be applied by applying a sol solution (curable resin composition) obtained by hydrolyzing two or more metal alkoxides and organopolysiloxane without using a reaction catalyst depending on various applications. It is produced by gelation and gelation by heating without using a reaction catalyst.
In addition, the thing before hydrolyzing the said metal alkoxide and organopolysiloxane and the thing in the middle of a hydrolysis reaction are also contained in the curable resin composition of this invention.

  The metal alkoxide and organopolysiloxane are hydrolyzed by adding both to a solvent and stirring, and then reacting the hydrolyzate of metal alkoxide with the organopolysiloxane, or adding water as necessary.

The solvent is not particularly limited as long as it can uniformly disperse and dissolve the metal alkoxide and organopolysiloxane.
For example, primary alcohols such as methanol, propanol and butanol, secondary alcohols such as isopropanol, isobutanol and sec-butyl alcohol, tertiary alcohols such as tert-butyl alcohol (t-butanol) and tert-amyl alcohol In addition to various alcohols such as ethyl acetate, methoxymethanol, methoxyethanol, ethoxymethanol, and 2-ethoxyethanol, organic solvents such as acetone, methyl ethyl ketone, toluene, and xylene are generally used.
From the viewpoint of the liquid stability (pot life) of the curable resin composition, it is desirable to use a tertiary alcohol such as tert-butyl alcohol or tert-amyl alcohol.

  For example, the metal alkoxide and the organopolysiloxane may be blended in the solvent at the same time, or only the metal alkoxide may be dissolved in advance and the organopolysiloxane may be blended. Furthermore, you may mix | blend organopolysiloxane with respect to the hydrolyzed metal alkoxide.

  The metal alkoxide and organopolysiloxane solution may be prepared separately for each metal alkoxide, or may be prepared by mixing all in one liquid, but divided into a plurality of liquids for each metal alkoxide. A method of preparing and mixing these liquids is preferable from the viewpoint of stability of reaction and stability of the resin composition after curing.

  As a quantitative ratio of the metal alkoxide and the organopolysiloxane to be mixed, the total amount of the metal alkoxide is preferably in the range of 2 to 60% by mass, more preferably in the range of 10 to 30% by mass. Is preferred.

  In addition, other components can be mix | blended with the said liquid mixture in the range which does not impair the effect | action and effect of this invention. Other components may be used alone or in combination of two or more.

  Other optional components include, for example, inorganic phosphors, anti-aging agents, radical inhibitors, UV absorbers, adhesion improvers, flame retardants, surfactants, storage stability improvers, ozone degradation inhibitors, and light stability. Agent, thickener, plasticizer, coupling agent, antioxidant, preservative, heat stabilizer, conductivity imparting agent, antistatic agent, radiation blocking agent, nucleating agent, phosphorus peroxide decomposing agent, lubricant, Examples thereof include pigments, metal deactivators and physical property modifiers.

  As described above, in the hydrolysis, a predetermined amount of water is added to the unhydrolyzed alkoxy group as necessary. In the present invention, a plurality of metal alkoxides and organopolysiloxanes are hydrolyzed in this step, and the amount of water is preferably in the range of 0.01 to 0.25% by mass with respect to the entire raw material liquid used for hydrolysis. , And more preferably in the range of 0.02 to 0.1% by mass.

  The hardness of the resin composition may vary after the condensation reaction due to atmospheric humidity, and it is preferable to add a small amount of water in advance. If the amount of water is less than 0.01% by mass, the resin composition may be highly uneven after the condensation reaction. On the other hand, if it exceeds 0.25% by mass, there may be a portion that is not sufficiently cured.

  In the hydrolysis, the necessary amount of water is added to the solution in which the metal alkoxide is dissolved, and the temperature is 10 to 35 ° C., preferably 20 to 25 ° C., for 0.1 to 2 hours, preferably 0.5 to 1. Do by stirring for hours.

  Next, the hydrolyzed sol solution is formed by applying, injecting or the like according to the shape of the element to be adapted. At this time, the solvent, alcohol produced by hydrolysis, etc. may be distilled off under normal pressure or reduced pressure.

  The application can be performed by, for example, a spray coating method, a dip coating method, a spray coating method, a roll coating method, a spin coating method, or the like, and the injection can be performed by, for example, a pressure injection method, an ink jet method, or the like.

After molding, a condensation reaction is performed by heating to obtain a cured product. At this time, the reaction catalyst is not used in the present invention.
The heating temperature is preferably in the range of 50 to 250 ° C, and more preferably in the range of 100 to 180 ° C.

  If it is lower than 50 ° C., the solvent or the like does not evaporate sufficiently, and hardness and heat resistance may not be obtained. If it exceeds 250 ° C., the heat energy required for heating is large, which is not preferable from the viewpoint of energy saving and may increase the cost. The heating time is preferably in the range of 0.5 to 6 hours, and more preferably in the range of 1 to 4 hours.

  In the condensation reaction, the heating is desirably performed according to the following procedure.

  First, regarding the initial stage of heating, the temperature in a heater such as an oven is set to a sufficiently high temperature before the molded product of the sol solution is charged, and the sol solution is charged into the heater and the temperature is rapidly increased from the beginning. It is desirable to perform heating. Thereby, the dispersion | variation in the characteristic of the resin composition for optical elements which is hardened | cured material can be minimized.

  Since the cured body (resin composition for optical elements) thus obtained contains almost no metal oxide or the like, it can maintain high optical transparency in the near-ultraviolet to visible wavelength region.

  Specifically, in 10 mm × 30 mm × thickness 2 mm, the light transmittance at a wavelength of 350 to 800 nm is desirably 85% or more, and more preferably 90% or more.

  Furthermore, since the resin composition for optical elements of the present invention has a crosslinked structure based on the plurality of metal alkoxides, high light resistance and heat resistance are exhibited.

Specifically, the resin composition for an optical element preferably has a transmittance of 80% or more at 350 to 800 nm even after irradiation with light having a wavelength of 365 nm and a light amount of 3000 mW / cm ² for 24 hours, and 85% or more. Is more desirable. If the transmittance after light irradiation is in the above range, for example, sufficient optical characteristics can be maintained even for long-term use in each color LED.

  Further, the transmittance at 350 to 800 nm after being left in an atmosphere of 200 ° C. for 200 hours is desirably 85% or more, and more desirably 90% or more. If the transmittance after the heat treatment is in the above range, for example, heat deterioration due to heat generation in the used optical element is not caused and sufficient optical characteristics can be maintained.

  The resin composition for optical elements of the present invention is particularly useful as a sealing material for LED elements, and is excellent in light resistance and heat resistance. Therefore, the LED element is a blue LED element or an ultraviolet LED element. It is also useful as a material and exhibits excellent durability even in a high luminance environment. Furthermore, this sealing material can efficiently extract light from the light emitting element.

  In addition, due to its excellent heat resistance, light resistance, transparency, etc., the following display materials, optical recording medium materials, optical equipment materials, optical component materials, optical fiber materials, optical / electronic functional organic materials, It can also be used for applications such as semiconductor integrated circuit peripheral materials.

  Examples of the display material include a liquid crystal display substrate material, a light guide plate, a prism sheet, a deflector plate, a retardation plate, a viewing angle correction film, an adhesive, a liquid crystal film such as a polarizer protective film, etc. Materials: Sealant for color plasma display (PDP), next-generation flat panel display, antireflection film, optical correction film, housing material, front glass protective film, front glass substitute material, adhesive, front glass protective film Alternative materials for front glass, adhesives, etc .; substrate material for plasma addressed liquid crystal (PALC) display, light guide plate, prism sheet, deflector plate, retardation plate, viewing angle correction film, adhesive, polarizer protective film, etc .; organic EL (Electroluminescence) Protective film for front glass of display, Surface glass substitute material, adhesive or the like; various film substrate of a field emission display (FED), front glass protective films, front glass substitute material, adhesives and the like.

  Examples of the optical recording material include VD (video disc), CD, CD-ROM, CD-R / CD-RW, DVD ± R / DVD ± RW / DVD-RAM, MO, MD, PD (phase change disc). ), Disk substrate materials for optical cards, pickup lenses, protective films, sealants, adhesives, and the like.

  Examples of the optical device material include a steel camera lens material, a finder prism, a target prism, a finder cover, a light receiving sensor unit, a video camera photographing lens, a finder, and the like; a projection television projection lens, a protective film, and a seal Agents, adhesives, and the like; materials for lenses of optical sensing devices, sealants, adhesives, films, and the like.

  Examples of the optical component material include a fiber material around an optical switch, a lens, a waveguide, an element sealant, and an adhesive in an optical communication system; an optical fiber material around an optical connector, a ferrule, a sealant, and an adhesive Agents, etc .: Optical passive components, optical circuit components, lenses, waveguides, LED element sealants, adhesives, etc .; substrate materials, fiber materials, element sealants, adhesives around optoelectronic integrated circuits (OEIC) Agents and the like.

  Examples of the optical fiber material include decorative display illumination / light guides, etc .; industrial sensors, displays / signs, etc .; optical fibers for communication infrastructure and for connecting digital devices in the home.

  Examples of the peripheral material for the semiconductor integrated circuit include a resist material for microlithography of LSI and VLSI material.

  Further, examples of the optical / electronic functional organic material include organic EL element peripheral materials, organic photorefractive elements; optical amplification elements that are light-to-light conversion devices, optical arithmetic elements, substrate materials around organic solar cells; fiber materials A sealing agent and an adhesive for these elements.

  EXAMPLES Hereinafter, although an Example demonstrates this invention more concretely, this invention is not limited at all by these Examples. In the examples and comparative examples, “parts” and “%” mean “parts by mass” and “% by mass” unless otherwise specified.

<Measurement methods for various properties>
Various measurements in Examples and Comparative Examples were performed by the following methods.

(Optical transparency)
Each curable resin composition obtained was cut into 10 mm × 30 mm × film thickness 2 mm, and the spectral transmittance (% T) at a wavelength of 350 to 800 nm was measured using a spectrophotometer U-3300 (manufactured by Hitachi, Ltd.). did.

(Refractive index)
Each curable resin composition obtained was cut into 10 mm × 30 mm × film thickness 2 mm to prepare a resin composition for optical elements. About this hardening body, the refractive index of the light of wavelength 587nm in 25 degreeC was measured with the Abbe refractometer made from an Atago company.

(Light resistance, heat resistance)
Samples for light transmission tests prepared under the above conditions were each light-resistant, using a UV spot irradiation device SP-9 manufactured by Ushio Electric Co., Ltd., in an atmosphere of 60 ° C., having a wavelength of 365 nm and a light amount of 3000 mW / cm ² . Light was irradiated for 24 hours, and for heat resistance, a heating oven was used and left in an atmosphere of 200 ° C. for 200 hours, and then the light transmittance was measured under the measurement conditions described above, and compared with the initial state.

(Preparation of raw material liquid)
Tetraisopropoxy titanium (TIPT) (manufactured by Kanto Chemical Co., Inc.) 0.2% by mass is added to 8.2% by mass of t-butanol (manufactured by Wako Pure Chemical Industries, Ltd.), and tetraethoxysilane (TEOS) (Kanto Chemical) (Made by company) 10.2 mass% was added and stirred.

  This solution was put into 81.4% by mass of polydimethylsiloxane (PDMS) (weight average molecular weight: 20000, trade name: XF3905, manufactured by GE Toshiba Silicone), and stirred at room temperature for 30 minutes to obtain a raw material solution (curability). Resin composition) was obtained.

(Preparation of resin composition for optical element)
The raw material liquid was poured into a petri dish made of fluororesin and cured at 100 ° C. for 1 hour in a batch type oven, followed by baking at 120 ° C. for 3 hours (dehydration condensation step) to obtain a cured product.

(Evaluation)
-Initial characteristics-
-Curing characteristics The cured product was evaluated according to the following criteria by visual observation and finger touch.
(Double-circle): It has fully hardened | cured so that it may not drip, and hardness is also uniform.
○: Although sufficiently cured, bubbles are observed.
(Triangle | delta): Although it hardens | cures as a whole, there exists a part with a one part soft feeling and tackiness.
X: Curing is insufficient and dripping as a liquid.
The evaluation results are shown in Table 1.

<Optical characteristics>
Under the conditions described above, the refractive index of light having a wavelength of 587 nm and the light transmittance of 350 to 800 nm at 25 ° C. of the cured product were measured. The results are shown in Table 1.

<Light resistance and heat resistance>
About each sample which performed the light resistance test and the heat resistance test on the above-mentioned conditions, the said light transmittance was measured and compared with the initial stage characteristic. The results are shown in Table 1.

  In the preparation of the raw material liquid of Example 1, a resin composition for an optical element was prepared in the same manner except that isopropyl alcohol was used instead of t-butanol as a solvent, and the same evaluation was performed. The results are shown in Table 1.

  In addition, when the raw material liquid prepared in this example was allowed to stand for 24 hours from the preparation of the liquid and then cured again, sufficient curing characteristics were not obtained as compared with the other examples.

(Preparation of raw material liquid)
-Raw material liquid A-
Tetraethoxysilane (TEOS) (manufactured by Kanto Chemical Co., Inc.) 20.5% by mass, polydimethylsiloxane (PDMS) (weight average molecular weight: 20000, trade name: XF3905, manufactured by GE Toshiba Silicone), 76.9% by mass, 2.5% by mass of t-butanol (manufactured by Wako Pure Chemical Industries, Ltd.) and 0.1% by mass of water were mixed and stirred at room temperature for 30 minutes to obtain a raw material liquid A.

-Raw material liquid B-
Tetraisopropoxytitanium (TIPT) (manufactured by Kanto Chemical Co., Inc.) 0.5% by mass, polydimethylsiloxane (PDMS) (weight average molecular weight: 20000, trade name: XF3905, manufactured by GE Toshiba Silicone) 86% by mass, t -Butanol (made by Wako Pure Chemical Industries) 13.5 mass% was mixed, this was stirred at room temperature for 30 minutes, and the raw material liquid B was obtained.

(Preparation of resin composition for optical element)
The raw material liquid A and the raw material liquid B were mixed at a mass ratio of 1/1, stirred at room temperature for 30 minutes (hydrolysis step), and then defoamed to obtain a colorless and transparent liquid.

  This liquid is poured into a petri dish made of fluororesin, cured at 100 ° C. for 1 hour, and then baked at 120 ° C. for 3 hours (dehydration condensation process) to obtain a colorless and transparent cured product (resin composition for optical elements). It was. Evaluation similar to Example 1 was performed about this hardened | cured material. The results are shown in Table 1.

  In the preparation of the raw material liquid A of Example 3, a resin composition for an optical element was prepared in the same manner except that PDMS was 77.0% by mass and water was not used, and the same evaluation was performed. The results are shown in Table 1.

  In the preparation of the raw material liquid A of Example 3, a resin composition for an optical element was prepared in the same manner except that PDMS was 77.0% by mass and water was 0.14% by mass, and the same evaluation was performed. . The results are shown in Table 1.

(Comparative Example 1)
In the preparation of the raw material liquid of Example 1, TIPT was 0.1% by mass, t-butanol was 13.0% by mass, and an attempt was made to produce a resin composition for an optical element in the same manner except that TEOS was not used. However, a cured product was not obtained after heating.

(Comparative Example 2)
In the preparation of the raw material liquid of Example 1, TEOS was 9.8% by mass, t-butanol was 11.8% by mass, and an attempt was made to produce a resin composition for an optical element in the same manner except that TIPT was not used. However, a cured product was not obtained after heating.

  As shown in Table 1, when a plurality of metal alkoxides of Examples are used, sufficient curing is performed without using a catalyst for the condensation reaction, and the cured product has high transparency, light resistance, and heat resistance. Was maintained. On the other hand, in a comparative example using one kind of metal alkoxide, a cured product was not obtained.

  The colorless and transparent cured product (resin composition for optical elements) obtained in Example 3 was subjected to the following evaluation test.

(Evaluation test 1)
The transparency when the cured product was allowed to stand for 200 hours in an environment of 200 ° C. was measured using the spectrophotometer U-3300 described above.
The initial data was 89.0 to 91.6% T, whereas it was 90.2 to 92.4% T after being left at 200 ° C. for 200 hours.

(Evaluation test 2)
The weight loss when the cured product was allowed to stand in an environment of 200 ° C. for 200 hours was measured.
When the initial data was 100, it was 97.4 after being left at 200 ° C. for 200 hours. That is, the weight loss was 2.6%.

(Evaluation test 3)
The cured product was visually inspected for maintaining its transparency when left in an environment of 150 ° C. for 400 hours. As the evaluation criteria, as a result of visual observation, if there was no peeling, cracking, void, and white turbidity, ○ (= no change in state (degeneration)), and if there was peeling, cracking, void, or white turbidity, it was rated as x. The result was ○.

(Evaluation test 4)
The cured product was subjected to an ultraviolet resistance test using the above-described UV spot irradiation apparatus SP-9. The test conditions were a wavelength of 400 nm, an illuminance center part 10 w / cm ² , an illuminance peripheral part 5 w / cm ² , and a test time of 350 hours. The evaluation criteria are the same as those in the evaluation test 3. The result was ○.

(Evaluation test 5)
The cured product was subjected to a high temperature and high humidity test for 150 hours in an environment of 80 ° C. and 85% Rh. The evaluation criteria are the same as those in the evaluation test 3. The result was ○.

(Evaluation test 6)
The cured product was subjected to a high temperature and high humidity test for 140 hours in an environment of 60 ° C. and 60% Rh. The evaluation criteria are the same as those in the evaluation test 3. The result was ○.

(Evaluation test 7)
About the hardened | cured material, the heat cycle test which repeats -40 degreeC and 120 degreeC 600 cycles was done. The evaluation criteria are the same as those in the evaluation test 3. The result was ○.

(Evaluation test 8)
The tensile strength was measured before and after the cured product was left in an environment of 200 ° C. for 60 hours. The measuring instrument used was a universal testing machine (model number: AGS-1kNG) manufactured by Shimadzu Corporation. As a result, it was found that both initial data and post-test data were 0.5 MPa and did not change before and after being left for 60 hours.

Examples where PDMS is put only in the raw material liquid A will be shown below.
(Preparation of raw material liquid)
-Raw material liquid A-
0.2% by mass of tetraisopropoxy titanium (TIPT) (manufactured by Wako Pure Chemical Industries) and 98% by mass of polydimethylsiloxane (PDMS) (weight average molecular weight: 20000, trade name: XF3905, manufactured by GE Toshiba Silicone) , T-butanol (manufactured by Wako Pure Chemical Industries, Ltd.) 1.8% by mass was mixed and stirred at room temperature for 30 minutes to obtain a raw material liquid A.

-Raw material liquid B-
Tetraethoxysilane (TEOS) (manufactured by Kanto Chemical Co., Inc.) 93% by mass, t-butanol (manufactured by Wako Pure Chemical Industries, Ltd.) 6.8% by mass, and water 0.2% by mass are mixed at room temperature. The mixture was stirred for 30 minutes to obtain a raw material liquid B.

(Production of cured resin molding)
The raw material liquid A was mixed at a mass ratio of the raw material liquid B = 7: 1, and after stirring for 30 minutes at room temperature (hydrolysis step), a colorless and transparent liquid was obtained.
This liquid was poured into a fluororesin petri dish (mold) and baked at 120 ° C. for 4 hours (dehydration condensation process) to obtain a transparent cured product (cured resin molded product).

  An example in which tetrabutoxyzirconium (TBZR) is used in place of tetraisopropoxytitanium (TIPT) in Example 7 is shown below.

(Preparation of raw material liquid)
-Raw material liquid A-
Tetrabutoxyzirconium (TBZR) (manufactured by Wako Pure Chemical Industries, Ltd.) 0.5% by mass and polydimethylsiloxane (PDMS) (weight average molecular weight: 20000, trade name: XF3905, manufactured by GE Toshiba Silicone) 95.2% by mass And t-butanol (manufactured by Wako Pure Chemical Industries, Ltd.) 4.3 mass% were mixed and stirred at room temperature for 30 minutes to obtain a raw material liquid A.

-Raw material liquid B-
Tetraethoxysilane (TEOS) (manufactured by Kanto Chemical Co., Inc.) 93% by mass, t-butanol (manufactured by Wako Pure Chemical Industries, Ltd.) 6.8% by mass, and water 0.2% by mass are mixed at room temperature. The mixture was stirred for 30 minutes to obtain a raw material liquid B.

(Production of cured resin molding)
The raw material liquid A and the raw material liquid B were mixed at a mass ratio of 10: 1 and stirred at room temperature for 30 minutes (hydrolysis step) to obtain a colorless and transparent liquid.
This liquid was poured into a fluororesin petri dish (mold) and baked at 120 ° C. for 4 hours (dehydration condensation process) to obtain a transparent cured product (cured resin molded product).

Below, the Example at the time of changing the solvent in Example 3 into ethyl acetate is shown.
(Preparation of raw material liquid)
-Raw material liquid A-
Tetraethoxysilane (TEOS) (manufactured by Kanto Chemical Co., Inc.) 20.5% by mass, polydimethylsiloxane (PDMS) (weight average molecular weight: 20000, trade name: XF3905, manufactured by GE Toshiba Silicones) 77% by mass, ethyl acetate 2.4% by mass (manufactured by Wako Pure Chemical Industries, Ltd.) and 0.1% water were mixed and stirred at room temperature for 30 minutes to obtain a raw material liquid A.

-Raw material liquid B-
Tetraisopropoxy titanium (TIPT) (manufactured by Wako Pure Chemical Industries, Ltd.) 0.5 mass% and polydimethylsiloxane (PDMS) (weight average molecular weight: 20000, trade name: XF3905, manufactured by GE Toshiba Silicone) 83.5 mass % And ethyl acetate (manufactured by Wako Pure Chemical Industries, Ltd.) 16% by mass were mixed and stirred at room temperature for 30 minutes to obtain a raw material liquid B.

(Production of cured resin molding)
The raw material liquid A and the raw material liquid B were mixed at a mass ratio of 1: 1, and after stirring for 30 minutes at room temperature (hydrolysis step), a colorless and transparent liquid was obtained.
This liquid was poured into a fluororesin petri dish (mold) and baked at 120 ° C. for 4 hours (dehydration condensation process) to obtain a transparent cured product (cured resin molded product).

(Comparative Example 3)
Below, the comparative example at the time of changing the solvent in Example 3 into ethanol is shown.
(Preparation of raw material liquid)
-Raw material liquid A-
Tetraethoxysilane (TEOS) (manufactured by Kanto Chemical Co., Inc.) 20.5% by mass, polydimethylsiloxane (PDMS) (weight average molecular weight: 20000, trade name: XF3905, manufactured by GE Toshiba Silicone) 77% by mass, ethanol ( 2.4% by mass (manufactured by Wako Pure Chemical Industries, Ltd.) and 0.1% water were mixed and stirred at room temperature for 30 minutes to obtain a raw material liquid A.

-Raw material liquid B-
Tetraisopropoxy titanium (TIPT) (manufactured by Wako Pure Chemical Industries, Ltd.) 0.5% by mass and polydimethylsiloxane (PDMS) (weight average molecular weight: 20000, trade name: XF3905, manufactured by GE Toshiba Silicone) 89.5 mass % And ethanol (manufactured by Wako Pure Chemical Industries, Ltd.) 10 mass% were mixed and stirred at room temperature for 30 minutes to obtain a raw material liquid B.

(Production of cured resin molding)
The raw material liquid A and the raw material liquid B were mixed at a mass ratio of 1: 1, and after stirring for 30 minutes at room temperature (hydrolysis step), a colorless and transparent liquid was obtained.
This liquid was poured into a fluororesin petri dish (mold) and baked at 120 ° C. for 4 hours (dehydration condensation step), but a completely cured product (cured resin molded product) could not be obtained.

(Comparative Example 4)
Below, the comparative example at the time of changing the solvent in Example 3 into dimethylformamide is shown.

(Preparation of raw material liquid)
-Raw material liquid A-
Tetraethoxysilane (TEOS) (manufactured by Kanto Chemical Co., Inc.) 20.5% by mass, polydimethylsiloxane (PDMS) (weight average molecular weight: 20000, trade name: XF3905, manufactured by GE Toshiba Silicones) 77% by mass, dimethylformamide (Made by Kanto Chemical Co., Inc.) 2.4 mass% and water 0.1% were mixed, and this was stirred at room temperature for 30 minutes to obtain a raw material liquid A.

-Raw material liquid B-
0.5% by mass of tetraisopropoxy titanium (TIPT) (manufactured by Wako Pure Chemical Industries) and 86% by mass of polydimethylsiloxane (PDMS) (weight average molecular weight: 20000, trade name: XF3905, manufactured by GE Toshiba Silicone) And 13.5% by mass of dimethylformamide (manufactured by Kanto Chemical Co., Inc.) were mixed and stirred at room temperature for 30 minutes to obtain a raw material liquid B.

(Production of cured resin molding)
The raw material liquid A and the raw material liquid B were mixed at a mass ratio of 1: 1, and after stirring for 30 minutes at room temperature (hydrolysis step), a cloudy liquid was obtained.
This liquid was poured into a fluororesin petri dish (mold) and baked at 120 ° C. for 4 hours (dehydration condensation process). However, a colorless and transparent cured product (cured resin molded product) was not obtained, and the cloudy cured product was Obtained.

  The above-described embodiments are illustrated for the purpose of explanation, and the present invention is not limited to them. Those skilled in the art will recognize from the claims and the detailed description of the invention. Modifications and additions can be made without departing from the technical idea of the present invention.

Claims (5)

  A resin composition for an optical element, characterized in that a condensation reaction of two or more metal alkoxides and an organopolysiloxane is carried out without adding a reaction catalyst.   The resin composition for an optical element according to claim 1, wherein the two or more metal alkoxides include a silicon alkoxide and a titanium alkoxide. The optical element resin according to claim 1 or 2, wherein a light transmittance at 350 to 800 nm after irradiation with light having a wavelength of 365 nm and a light amount of 3000 mW / cm ² for 24 hours in an atmosphere of 60 ° C is 80% or more. Composition   4. The resin composition for an optical element according to claim 1, wherein the light transmittance at 350 to 800 nm after being left in an atmosphere of 200 ° C. for 200 hours is 85% or more. 5. A curable resin composition used for the resin composition for an optical element according to any one of claims 1 to 4,
Curable resin composition comprising a plurality of metal alkoxides and organopolysiloxane