JP5046239B2 - Organic inorganic composite - Google Patents

Description

  The present invention relates to an organic-inorganic composite, and more particularly to an organic-inorganic composite having a high light transmittance for visible light and capable of improving the refractive index and toughness.

  Conventionally, a glass substrate has been often used as a substrate for a flat panel display (FPD) such as a liquid crystal display (LCD), a plasma display (PDP), and an electroluminescence display (EL). However, the glass substrate has problems that it is easily broken, cannot be bent, has a large specific gravity, and is not suitable for weight reduction. Therefore, many attempts have been made to use a plastic substrate having flexibility instead of a glass substrate.

Properties required for plastic substrates for flat panel display (FPD) applications include transparency, refractive index, and mechanical properties.
As inorganic oxide fillers for improving the refractive index of plastic materials, oxide fine particles such as zirconia and titania are used as high refractive index fillers.
Further, in order to make the inorganic oxide filler complex with the resin, a dispersion liquid in which the inorganic oxide filler is dispersed in an aqueous solvent or an organic solvent has been developed, and an improvement in the refractive index of the resin has been studied.
As an example of this composite, a film having a high refractive index and a high transparency of several microns in thickness using a zirconia particle composite plastic in which a zirconia particle having a particle diameter of 10 to 100 nm and a resin are combined has been proposed ( For example, see Patent Document 1).

On the other hand, hydrophilic resins are widely used from pharmaceuticals and daily necessities to industrial raw materials because of their excellent solubility and processability in water and various organic solvents. In particular, in optical applications, characteristics such as high light transmittance and high refractive index are required, and various characteristics such as high thermal stability and high hardness are required.
As a hydrophilic resin for these optical applications, a composition in which a metal oxide is combined with polyvinyl alcohol has been proposed as an attempt to arbitrarily control the refractive index (see, for example, Patent Document 2).
Japanese Patent Laying-Open No. 2005-161111 JP-T 09-500974

By the way, when evaluating the transparency of a substrate using a conventional plastic compounded with inorganic oxide particles, the thickness of the substrate is taken as the optical path length, and the visible light transmittance at this optical path length is obtained. Therefore, if the substrate is thick, it becomes difficult to maintain its transparency.
For example, in the case of a film made of the above-mentioned conventional zirconia particle composite plastic, a thickness of several μm ensures a high refractive index and high transparency, so that the thickness is several tens of μm or more. Then, it becomes difficult to maintain transparency.

In addition, when metal oxide particles such as zirconia particles are combined with a hydrophobic resin, the metal oxide particles and the resin are separated because the surface of the metal oxide particles is hydrophilic. However, it is difficult to form a composite with metal oxide particles while maintaining the transparency of the resin.
Therefore, as a general solution, in order to make the surface of the metal oxide particles hydrophobic, an organic polymer dispersing agent or the like is applied to the surface of the metal oxide particles, so that the phase of the metal oxide particles and the resin is reduced. The device which raises solubility is made.

  However, it is possible to enhance the compatibility between the metal oxide particles and the hydrophobic resin by applying an organic polymer dispersant or the like to the surface of the metal oxide particles. Has a problem in that it contains a large amount of an organic polymer dispersant, so that the amount of metal oxide particles added is limited, and as a result, improvement of its optical function is limited. In addition, there is a problem that the heat resistance is reduced due to the organic polymer dispersant.

  Such problems may also be seen with polyvinyl alcohol, which is a hydrophilic resin, and the resin itself aggregates due to the interaction between the resin and the metal oxide particles due to hydrogen bonding. There is a case where a problem arises when the resin is compounded with polyvinyl alcohol resin without surface treatment. Therefore, when the surface treatment is performed on the metal oxide particles, the compatibility between the metal oxide particles and the resin is increased, and a transparent zirconia particle composite plastic is obtained, but the heat resistance due to the organic components on the surface of the metal oxide particles is obtained. There was a risk of lowering.

In addition, conventional optical functional films, optical films, and optical lenses made of resin generally have low thermal stability, and have disadvantages such as fluctuations in optical characteristics, particularly under high temperature environments. There was a problem that it was difficult to cope with high thermal stability.
In addition, even plastic lenses that are said to have excellent heat resistance and chemical resistance have a low refractive index and are not so high in heat resistance, and it is difficult to meet demands for high thermal stability and high refractive index. It was.

As a conventional material having a high refractive index, there is a composite material in which a high refractive index filler such as zirconia, titania or tin oxide is contained in a resin.
However, in the conventional composite material, any high refractive index filler having a primary particle diameter of a few μm to a fine one of several nanometers is agglomerated, and even if kneaded in a resin, the particles Since it exists in the state of coarse particles having a diameter of several μm, the high refractive index filler could not be uniformly dispersed in the resin. Therefore, there is a problem that it is difficult to further improve the light transmittance, refractive index, and toughness of the composite material with respect to visible light.

  This invention is made | formed in view of the said situation, Comprising: It aims at providing the organic-inorganic composite_body | complex which has high transparency and can improve a refractive index, toughness, and heat resistance.

  The present inventors show that when zirconia particles as an inorganic filler, particularly tetragonal zirconia is added as the second phase of the composite material, the composite material exhibits high toughness due to volume expansion called martensitic transformation. Attention is focused on the fact that conventional zirconia particles have a large primary particle diameter of several μm to a few nanometers, and agglomeration is intense, and even when kneaded in resin, the particle diameter is several μm. As a result of intensive studies in order to overcome the disadvantage that transparency is lost in the state of coarse particles, tetragonal zirconia particles having an average dispersed particle size of 1 nm or more and 20 nm or less are used as zirconia particles. High optical transmittance, high refractive index, high thermal stability, high hardness if optical functional film, optical film and optical lens are composed of organic-inorganic composite containing tetragonal zirconia particles And they found that the weather resistance was satisfied, and completed the present invention.

That is, the organic-inorganic composite of the present invention, the average dispersed particle diameter of 1nm or more and 20nm or less tetragonal zirconia particles, Ri name contains a hydrophilic resin having a nitrogen atom in the main chain or side chain, wherein The hydrophilic resin is characterized by comprising polyoxazolines .

The hydrophilic resin in the previous period is preferably made of either polyvinylpyrrolidone or polyoxazoline.
It is preferable that the tetragonal zirconia particles are dispersed in the hydrophilic resin.
The content of the tetragonal zirconia particles is preferably 1% by mass or more and 90% by mass or less.

  According to the organic-inorganic composite of the present invention, it contains tetragonal zirconia particles having an average dispersed particle diameter of 1 nm or more and 20 nm or less, and a hydrophilic resin containing nitrogen atoms in the main chain or side chain. Transparency can be maintained and refractive index and toughness can be improved.

The best mode of the organic-inorganic composite of the present invention will be described.
This embodiment is specifically described for better understanding of the gist of the invention, and does not limit the present invention unless otherwise specified.

"Organic inorganic composite"
FIG. 1 is a schematic cross-sectional view showing one embodiment of a composite substrate provided with the organic-inorganic composite of the present invention.
The composite base material 10 of this embodiment is roughly composed of a flat transparent base material 11 and an organic-inorganic composite 12 formed on one surface 11 a of the transparent base material 11. The entire organic / inorganic composite 12 forms a light transmission region.

  The organic-inorganic composite 12 is a transparent composite in which tetragonal zirconia particles having an average dispersed particle diameter of 1 nm or more and 20 nm or less are dispersed in a hydrophilic resin containing nitrogen atoms in the main chain or side chain.

  Here, the reason for limiting the zirconia particles to tetragonal zirconia particles is that when the particle size of the fine particles is reduced to 20 nm or less, the tetragonal crystal becomes more stable than the conventionally known monoclinic crystal, and In the transparent composite in which the hardness is high and the mechanical properties of the transparent composite are improved and the zirconia particles are dispersed in the resin, when tetragonal zirconia particles are added as the second phase, This is because, as compared with the case where oblique zirconia particles are added, high toughness is exhibited by volume expansion called martensitic transformation.

The reason why the average dispersed particle size of the tetragonal zirconia particles is limited to 1 nm or more and 20 nm or less is that when the average dispersed particle size is less than 1 nm, the crystallinity is poor and the particle characteristics such as refractive index are exhibited. On the other hand, if the average dispersed particle size exceeds 20 nm, the transparency is lowered in the case of a dispersion or a transparent composite.
Thus, since the tetragonal zirconia particles are nano-sized particles, even if they are combined with a resin to form a transparent composite, light scattering is small, and the transparency of the composite can be maintained.

  Since the organic-inorganic composite 12 can maintain high transparency, the thickness of the organic-inorganic composite 12 is preferably 0.1 μm or more and 1 cm or less, more preferably 1 μm or more and 1 mm or less in order to obtain an optical function.

The content of tetragonal zirconia particles in the organic-inorganic composite 12 is preferably 1% by mass to 90% by mass, more preferably 5% by mass to 80% by mass, and still more preferably 10% by mass to 75% by mass. % Or less.
Here, the reason why the content of tetragonal zirconia particles is limited to 1% by mass or more and 90% by mass or less is that the lower limit of 1% by mass is an additive that can improve the refractive index, mechanical characteristics, and thermal characteristics. This is because the upper limit of 90% by mass is the maximum value of the addition rate that can maintain the characteristics (flexibility) of the resin itself.

In the organic-inorganic composite 12, when the content of tetragonal zirconia particles is 25% by mass, the visible light transmittance is preferably 90% or more, more preferably 92% or more when the optical path length is 1 mm.
This visible light transmittance varies depending on the content of tetragonal zirconia particles in the organic-inorganic composite 12, and is 95% or more when the content of tetragonal zirconia particles is 1% by mass, and the content of tetragonal zirconia particles is 40% by mass. Then, it is 80% or more.

In addition, since the refractive index of tetragonal zirconia particles is 2.15, by dispersing the tetragonal zirconia particles in the resin, the refractive index is higher than that of the polyvinylpyrrolidone resin having a refractive index of about 1.25. It is possible to improve it.
Further, the tetragonal zirconia particles can be expected to improve the toughness value due to martensitic transformation as compared with the monoclinic zirconia particles, and have high toughness and hardness, and are suitable for improving the mechanical properties of the composite.
In addition, since tetragonal zirconia particles are nano-sized particles, even when they are combined with a resin, light scattering is small and the transparency of the composite can be maintained.

As the hydrophilic resin containing a nitrogen atom in the main chain or side chain, polyvinylpyrrolidone or polyoxazoline is preferably used. Although it does not specifically limit as polyvinylpyrrolidone (Polyvinylpyrrolidone, PVP), For example, the molecular weight is 1000 or more and 1000000 or less.
Although it does not specifically limit as polyoxazoline, For example, the molecular weight is 1000 or more and 1 million or less.
Other hydrophilic resins containing nitrogen atoms in the main chain or side chain include polyoxazolines such as poly-2-methyl 2-oxazoline and poly-2-butyl 2-oxazoline, polyacrylamide, and polydimethylacrylamide. And polyamides such as polyisopropylacrylamide, polyvinylformamide, polyvinylacetamide, and polyvinylisobutyramide.

Polyvinyl pyrrolidone and polyoxazoline are hydrophilic resins having a hydrophilic group.
Here, having a hydrophilic group is an essential condition for dispersing tetragonal zirconia particles not subjected to surface treatment in the resin. Furthermore, if the resin is water-soluble, the resin can be dissolved in the aqueous dispersion of tetragonal zirconia particles, so that the tetragonal zirconia particles and the resin can be easily mixed uniformly in water. Then, by removing water after mixing, an organic-inorganic composite in which tetragonal zirconia particles are uniformly dispersed in the resin can be easily produced.

In addition to the above, this organic-inorganic composite may contain other inorganic oxide particles, resin monomers, and the like as long as the characteristics are not impaired.
Examples of inorganic oxide particles other than the above include monoclinic or cubic zirconia particles, titanium oxide, cerium oxide, zinc oxide, tin oxide, antimony-added tin oxide (ATO), tin-added indium oxide (ITO), and the like. Is mentioned.

As the transparent substrate 11, a substrate made of an inorganic material or a resin substrate is used.
Examples of the base material made of an inorganic material include glass such as quartz glass, soda lime glass, and white plate glass, and a base material made of ceramics such as sapphire.
Examples of the resin substrate include acrylates such as polymethyl methacrylate (PMMA) and polycyclohexyl methacrylate, polycarbonate (PC), polystyrene (PS), polyether, polyester, polyarylate, polyacrylate, polyamide, and phenol-formaldehyde. (Phenol resin), diethylene glycol bisallyl carbonate, acrylonitrile / styrene copolymer (AS resin), methyl methacrylate / styrene copolymer (MS resin), poly-4-methylpentene, norbornene polymer, polyurethane, epoxy, silicone The base material which consists of etc. is mentioned.

  In this organic-inorganic composite, since tetragonal zirconia particles having an average dispersed particle diameter of 1 nm or more and 20 nm or less are dispersed in a hydrophilic resin containing nitrogen atoms in the main chain or side chain, transparency is maintained, The refractive index and toughness are also improved. Thereby, transparency, refractive index, thermal stability, hardness and weather resistance are improved, and thus reliability is improved over a long period of time.

"Method for producing organic-inorganic composite"
Next, the manufacturing method of the organic inorganic composite of the present invention will be described.
When producing this organic-inorganic composite, the following zirconia transparent dispersion is used.
This zirconia transparent dispersion is a dispersion containing tetragonal zirconia particles having a dispersed particle diameter of 1 nm or more and 20 nm or less and a dispersion medium.

The dispersion medium basically includes one or more of water, an organic solvent, a liquid resin monomer, and a liquid resin oligomer as a main component.
Examples of the organic solvent include alcohols such as methanol, ethanol, 2-propanol, butanol, and octanol, ethyl acetate, butyl acetate, ethyl lactate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, and γ-butyrolactone. Esters such as diethyl ether, ethylene glycol monomethyl ether (methyl cellosolve), ethylene glycol monoethyl ether (ethyl cellosolve), ethylene glycol monobutyl ether (butyl cellosolve), ethers such as diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, acetone, Methyl ethyl ketone, methyl isobutyl ketone, acetylacetone, cyclohexanone Any ketone, aromatic hydrocarbons such as benzene, toluene, xylene and ethylbenzene, and amides such as dimethylformamide, N, N-dimethylacetoacetamide and N-methylpyrrolidone are preferably used. One of these solvents Or 2 or more types can be used.

As the liquid resin monomer, acrylic or methacrylic monomers such as methyl acrylate and methyl methacrylate, and epoxy monomers are preferably used.
Moreover, as said liquid resin oligomer, a urethane acrylate oligomer, an epoxy acrylate oligomer, an acrylate oligomer, etc. are used suitably.

The content of tetragonal zirconia particles in the zirconia transparent dispersion is preferably 1% by mass to 70% by mass, more preferably 1% by mass to 50% by mass, and even more preferably 5% by mass to 30% by mass. % Or less.
Here, the reason why the content of the tetragonal zirconia particles is limited to 1% by mass or more and 70% by mass or less is that this range is a range in which the tetragonal zirconia particles can take a good dispersion state, and the content is 1% by mass. If it is less than%, the effect as tetragonal zirconia particles is reduced. On the other hand, if it exceeds 70% by mass, gelation and aggregation precipitation occur, and the characteristics as a dispersion are lost.

In addition to the above, the zirconia transparent dispersion may contain other inorganic oxide particles, resin monomers, and the like as long as the characteristics are not impaired.
As inorganic oxide particles other than tetragonal zirconia particles, monoclinic or cubic zirconia particles, titanium oxide, cerium oxide, zinc oxide, tin oxide, antimony-added tin oxide (ATO), tin-added indium oxide (ITO) Etc.

In the zirconia transparent dispersion, when the content of tetragonal zirconia particles is 5% by mass, the visible light transmittance is preferably 90% or more, more preferably 95% or more when the optical path length is 10 mm.
This visible light transmittance varies depending on the content of zirconia particles, and is 95% or more when the content of tetragonal zirconia particles is 1% by mass, and 80% or more when the content of tetragonal zirconia particles is 40% by mass.

Next, the above-mentioned zirconia transparent dispersion is mixed with a hydrophilic resin composed of either polyvinylpyrrolidone or polyoxazoline to prepare a mixed solution having a high fluidity.
Next, after this mixed solution is applied so as to cover one surface 11a of the transparent substrate 11 by various coating methods such as a spin coating method, a bar coating method, a flow coating method, and a dip method, a coating film is formed. The coating film is heated to remove the solvent (dispersion medium), and the organic-inorganic composite 12 in which tetragonal zirconia particles are uniformly dispersed in the resin is formed on the transparent substrate 11.
As described above, the organic-inorganic composite 12 of this embodiment shown in FIG. 1 can be produced.

As described above, according to this embodiment, since the organic-inorganic composite 12 in which tetragonal zirconia particles having a dispersed particle diameter of 1 nm or more and 20 nm or less are dispersed in a hydrophilic resin is provided, the organic-inorganic composite 12 Light transmittance, refractive index, thermal stability, hardness and weather resistance can be improved.
Therefore, it is possible to provide an organic-inorganic composite that is excellent in high light transmittance, high refractive index, high thermal stability, high hardness, and weather resistance.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further more concretely, this invention is not limited to a following example.

"Example 1"
(Preparation of zirconia transparent dispersion)
To a zirconium salt solution in which 2615 g of zirconium oxychloride octahydrate is dissolved in 40 L (liter) of pure water, dilute ammonia water in which 344 g of 28% ammonia water is dissolved in 20 L of pure water is added with stirring, and the zirconia precursor slurry is added. It was adjusted.
Next, an aqueous sodium sulfate solution in which 300 g of sodium sulfate was dissolved in 5 L of pure water was added to this slurry with stirring. The amount of sodium sulfate added at this time was 30% by mass with respect to the zirconia-converted value of zirconium ions in the zirconium salt solution.
Next, this mixture was dried in the air at 130 ° C. for 24 hours using a dryer to obtain a solid.
Next, this solid material was pulverized with an automatic mortar and then baked in the air at 500 ° C. for 1 hour using an electric furnace.
Next, the fired product is put into pure water, stirred to form a slurry, washed using a centrifuge, and after sufficiently removing the added sodium sulfate, dried in a drier. Tetragonal zirconia particles were prepared.

Next, 85 g of water as a dispersion medium was added to 15 g of the tetragonal zirconia particles, and a dispersion treatment was performed by a bead mill using 0.1 mmφ zirconia beads to prepare a zirconia transparent dispersion (Z1).
Next, the average dispersed particle diameter of tetragonal zirconia particles in this zirconia transparent dispersion (Z1) was measured.
For measuring the average dispersed particle size of tetragonal zirconia particles, a dynamic light scattering particle size distribution measuring device (Malvern) was used, and the content of tetragonal zirconia particles in the zirconia transparent dispersion (Z1) was set to 1. A sample prepared for mass% was used as a measurement sample.
As a result, the average dispersed particle diameter of tetragonal zirconia particles in the zirconia transparent dispersion (Z1) was 7 nm.

(Preparation of organic-inorganic composite)
Next, 7.11 g of methanol and 0.85 g of polyvinyl pyrrolidone (k30, manufactured by Wako Pure Chemical Industries, Ltd.) are added to 1.00 g of the above zirconia transparent dispersion (Z1) and mixed to prepare a zirconia / polyvinyl pyrrolidone mixed solution. did.
Next, this mixed solution was applied onto a 50 mm × 50 mm × 2 mm soda lime glass substrate by a bar coating method, and then pre-dried by heating at 60 ° C. for 24 hours with a dryer, and then at 80 ° C. under reduced pressure. And dried for 24 hours to prepare the organic-inorganic composite of Example 1.
The organic / inorganic composite was adjusted so that the film thickness after curing was 100 μm by repeatedly applying and drying the zirconia / polyvinylpyrrolidone mixed solution.
The content of tetragonal zirconia particles in the obtained organic-inorganic composite was 15% by mass.

"Example 2"
The organic of Example 2 was the same as Example 1 except that 6.29 g of methanol and 0.70 g of polyvinylpyrrolidone (k30, manufactured by Wako Pure Chemical Industries, Ltd.) were added to 2.00 g of the zirconia transparent dispersion (Z1). An inorganic composite was prepared.
The content of tetragonal zirconia particles in the obtained organic-inorganic composite was 30% by mass.

"Example 3"
The organic of Example 3 is the same as Example 1 except that 3.30 g of the zirconia transparent dispersion (Z1) is added with 5.20 g of methanol and 0.50 g of polyvinylpyrrolidone (K30, manufactured by Wako Pure Chemical Industries, Ltd.). An inorganic composite was prepared.
The content of tetragonal zirconia particles in the obtained organic-inorganic composite was 50% by mass.

Example 4
The organic of Example 4 was the same as Example 1 except that 3.69 g of methanol and 0.30 g of polyvinylpyrrolidone (k30, manufactured by Wako Pure Chemical Industries, Ltd.) were added to 4.67 g of the zirconia transparent dispersion (Z1). An inorganic composite was prepared.
The content of tetragonal zirconia particles in the obtained organic-inorganic composite was 70% by mass.

"Example 5"
The same procedure as in Example 1 was repeated except that 7.11 g of methanol and 0.85 g of poly-2-ethyl 2-oxazoline (average molecular weight 50000, manufactured by Aldrich) were added to 1.00 g of the zirconia transparent dispersion (Z1). 5 organic-inorganic composites were prepared.
The content of tetragonal zirconia particles in the obtained organic-inorganic composite was 15% by mass.

"Example 6"
The same procedure as in Example 1 was conducted, except that 3.67 g of methanol and 0.30 g of poly-2-ethyl 2-oxazoline (average molecular weight 50000, manufactured by Aldrich) were added to 4.67 g of the zirconia transparent dispersion (Z1). 6 organic-inorganic composite was produced.
The content of tetragonal zirconia particles in the obtained organic-inorganic composite was 70% by mass.

“Comparative Example 1”
To 7.9 g of methanol, 1.0 g of polyvinyl pyrrolidone (k30, manufactured by Wako Pure Chemical Industries, Ltd.) was added and mixed to prepare a polyvinyl pyrrolidone solution.
Next, this polyvinyl pyrrolidone solution was applied onto a 50 mm × 50 mm × 2 mm soda lime glass substrate by a bar coating method, heated at 60 ° C. for 24 hours with a dryer, preliminarily dried, and then subjected to 80 under reduced pressure. The organic-inorganic composite of Comparative Example 1 was produced by drying at 24 ° C. for 24 hours.
The organic / inorganic composite was adjusted so that the film thickness after curing was 100 μm by repeatedly applying and drying the polyvinylpyrrolidone solution.

"Comparative Example 2"
As the zirconia transparent dispersion (Z2), Zirconium (IV) oxide having a content of amorphous zirconia particles of 20% by mass, colloidal dispersion (Alfa-Aesar) was used.
The average particle size of the amorphous zirconia particles was 8 nm.
Next, 6.74 g of methanol and 0.70 g of polyvinylpyrrolidone (k30, manufactured by Wako Pure Chemical Industries, Ltd.) were added to 1.50 g of this zirconia transparent dispersion (Z2) and mixed to prepare a zirconia / polyvinylpyrrolidone mixed solution. .
Thereafter, an organic-inorganic composite of Comparative Example 2 was produced in the same manner as in Example 1.
The content of amorphous zirconia particles in the obtained organic-inorganic composite was 30% by mass.

“Comparative Example 3”
The organic of Comparative Example 3 is the same as Example 1 except that 5.95 g of methanol and 0.50 g of polyvinylpyrrolidone (k30, manufactured by Wako Pure Chemical Industries, Ltd.) are added to 2.50 g of the zirconia transparent dispersion (Z2). An inorganic composite was prepared.
The content of amorphous zirconia particles in the obtained organic-inorganic composite was 50% by mass.

“Comparative Example 4”
As the zirconia transparent dispersion (Z3), Zirconium (IV) oxide, colloidal dispersion (Alfa-Aesar) having a content of microcrystalline zirconia particles of 20% by mass was used.
The average particle size of the microcrystalline zirconia particles was 100 nm.
Next, 6.74 g of methanol and 0.70 g of polyvinylpyrrolidone (k30, manufactured by Wako Pure Chemical Industries, Ltd.) were added to 1.50 g of this zirconia transparent dispersion (Z3) and mixed to prepare a zirconia / polyvinylpyrrolidone mixed solution. .
Thereafter, an organic-inorganic composite of Comparative Example 4 was produced in the same manner as in Example 1.
The content of the microcrystalline zirconia particles in the obtained organic-inorganic composite was 30% by mass.

“Comparative Example 5”
The organic of Comparative Example 5 was the same as Example 1 except that 5.95 g of methanol and 0.50 g of polyvinylpyrrolidone (k30, manufactured by Wako Pure Chemical Industries, Ltd.) were added to 2.50 g of the zirconia transparent dispersion (Z3). An inorganic composite was prepared.
The content of the microcrystalline zirconia particles in the obtained organic-inorganic composite was 50% by mass.

“Comparative Example 6”
A polyoxazoline solution was prepared by adding and mixing 1.0 g of poly-2-ethyl 2-oxazoline (average molecular weight 50000, manufactured by Aldrich) to 7.9 g of methanol.
Next, this polyvinyl pyrrolidone solution was applied onto a 50 mm × 50 mm × 2 mm soda lime glass substrate by a bar coating method, heated at 60 ° C. for 24 hours with a dryer, preliminarily dried, and then subjected to 80 under reduced pressure. The organic-inorganic composite of Comparative Example 6 was produced by drying at 24 ° C. for 24 hours.
The organic-inorganic composite was adjusted so that the film thickness after curing was 100 μm by repeatedly applying and drying the polyoxazoline solution.

"Evaluation of organic-inorganic composites"
About each of the organic inorganic composite produced in Examples 1-6 and Comparative Examples 1-6, evaluation of visible light transmittance, refractive index, and glass transition temperature was performed by the following method.

(1) Visible light transmittance The transmittance | permeability of visible light was measured in the wavelength range of 350 nm-800 nm using the spectrophotometer (V-570, JASCO Corporation make).
Here, a 100 μm-thick organic film obtained by coating polyvinyl pyrrolidone (k30, manufactured by Wako Pure Chemical Industries, Ltd.) on a 50 mm × 50 mm × 2 mm soda lime glass substrate is used as a reference sample, and the transmittance between the glass substrate and the polyvinyl pyrrolidone film. When the transmittance was 100%, the visible light transmittance of 95% or more was evaluated as “◯”, and the transmittance of less than 95% was determined as “X”. The results are shown in Table 1.

(2) Refractive index The mixed solutions prepared in Examples 1 to 6 and Comparative Examples 1 to 6 were applied onto a silicon wafer by a spin coat method, dried to form an organic-inorganic composite, and the obtained organic The refractive index of the inorganic composite was measured using a spectroscopic ellipsometer.
The results are shown in Table 1.

(3) Glass transition temperature The mixed solutions prepared in Examples 1 to 6 and Comparative Examples 1 to 6 were preliminarily dried by heating at 60 ° C. for 24 hours, and then dried at 80 ° C. under reduced pressure for 24 hours. The organic-inorganic composite was formed, and the obtained organic-inorganic composite was subjected to glass transition using a differential scanning calorimeter (manufactured by Seiko Denshi Kogyo Co., Ltd.) under a nitrogen gas flow at a temperature rising rate of 5 ° C./min. The temperature was measured.
The results are shown in Table 1.

From the result of Table 1, since the organic-inorganic composites of Examples 1 to 6 have good visible light transmittance and refractive index, and the glass transition temperature is greatly improved, the high light transmittance and the high refractive index. It was found that the film was excellent in high thermal stability, high hardness and weather resistance.
On the other hand, the organic-inorganic composites of Comparative Examples 1 to 6 were inferior to Examples 1 to 6 in any of visible light transmittance, refractive index, and glass transition temperature.

  The organic-inorganic composite of the present invention contains tetragonal zirconia particles having an average dispersed particle diameter of 1 nm or more and 20 nm or less, and a hydrophilic resin composed of any one of polyvinylpyrrolidone and polyoxazoline, and comprises tetragonal zirconia particles. Since the surface of the substrate is not modified by the surface treatment agent, the refractive index, toughness and heat resistance can be improved and the transparency can be maintained. Therefore, the substrate for liquid crystal display devices and organic EL display devices can be used. Optical sheets such as substrates, color filter substrates, touch panel substrates, solar cell substrates, semiconductor laser (LED) sealing materials, transparent plates, optical lenses, optical elements, optical waveguides, etc. The effect is great even in various industrial fields.

It is a schematic sectional drawing which shows one Embodiment of the composite base material provided with the organic inorganic composite of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Composite base material 11 Transparent base material 12 Organic-inorganic composite

Claims (4)

Mean and dispersion particle diameter is 1nm or more and 20nm or less tetragonal zirconia particles, Ri name contains a hydrophilic resin having a nitrogen atom in the main chain or side chain,
The said hydrophilic resin consists of polyoxazolines, The organic inorganic composite characterized by the above-mentioned . 2. The organic-inorganic composite according to claim 1, wherein the hydrophilic resin is composed of any one of polyoxazoline, poly-2-methyl 2-oxazoline, and poly-2-butyl 2-oxazoline .   The organic-inorganic composite according to claim 1 or 2, wherein the tetragonal zirconia particles are dispersed in the hydrophilic resin.   4. The organic-inorganic composite according to claim 1, wherein the content of the tetragonal zirconia particles is 1% by mass or more and 90% by mass or less.

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