JPS63185820A - Production of modified titania sol - Google Patents

Abstract

PURPOSE:To obtain a modified titania sol having excellent dispersibility, long- term stability, light resistance, etc., by adding H2O2 to a gel or sol of hydrated titanic acid, heating the resultant solution in the presence of an inorganic compound and reacting the produced titania sol precursor with an Si compound or a Zr compound. CONSTITUTION:H2O2 is added to a sol and/or gel of hydrated titanic acid to effect the dissolution of the hydrated titanic acid and obtain a uniform aqueous solution having a TiO2 concentration of preferably about <=5wt.%. The hydrated titanic acid can be completely dissolved by adding the H2O2 at an H2O2/TiO2 ratio of >=1. The obtained aqueous solution of titanic acid is heated at >=60 deg.C, especially at >=80 deg.C in the presence of an inorganic compound to hydrolyze the titanic acid. The obtained titania sol precursor is reacted with an Si compound (e.g. silicic acid solution) or a Zr compound (e.g. ZrCl2). The modified titania sol produced by this process has the above characteristics and is stable over a wide pH range.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a titania sol, and more particularly to a method for producing a titania sol that has excellent dispersibility and is stable over a wide pH range.

Technical background and problems thereof In recent years, titanium oxide particles have been increasingly used to utilize their chemical properties. For example, titanium oxide is used as a surface coating material for decorative materials or plastics due to its ability to block ultraviolet rays, and as an antireflection coating material due to its high refractive index. They are used in combination as functional hard coat materials.

As mentioned above, titanium oxide is used for many purposes, but in each case, titanium oxide is required to have many functions. For example, when titanium oxide is used as a cosmetic material, it is required not only to have an ultraviolet shielding effect, but also to have smoothness, texture, transparency, etc. Furthermore, when titanium oxide is used as a coating material, in addition to transparency and a high refractive index, it is required to have even better film forming properties, adhesion, film hardness, mechanical strength, abrasion resistance, and the like.

In order to use titanium oxide particles for various purposes,
Titanium oxide particles are required to have various properties depending on their use, but ultrafine particles are preferable no matter what purpose they are used for. Furthermore, when titanium oxide particles are required to have transparency, the particles are required not only to have a uniform particle shape and size, but also to be highly dispersed in a medium during blending. In order to produce titanium oxide particles that satisfy these characteristics, it is particularly preferable to use highly dispersed colloidal titania (titania sol).

Conventional methods for producing titania sol include a method in which metatitanic acid obtained by hydrolyzing a titanium salt aqueous solution is neutralized and then washed, and the resulting gel is peptized with acid, or a titanium salt aqueous solution is Deionize with ion exchange resin etc. 1! ? A method is known in which 1 q of sol is reduced.

However, the titania sol produced by the above manufacturing method has the following problems.

- The dispersed particles of the sol are spherical or floor-shaped aggregates, and the particle size is non-uniform, resulting in cloudiness and poor transparency.

(2) Depending on the sol production conditions, it is possible to obtain a sol with small particle size and excellent transparency; however, in this case, a large amount of acid is required as a stabilizer.

(2) The sol is stable only in an acidic region (I3 or less), and in neutral or alkaline conditions, precipitation or gelation occurs, so its range of use is limited.

■ Even if the sol is mixed with an organic solvent such as alcohol, or if the solvent is replaced with an organic solvent, it becomes unstable and forms a precipitate, making it difficult to use as a hard coating agent on the surfaces of plastics, etc.

(2) Since titania particles obtained from titania sol have a high specific surface area and strong surface activity, when mixed with a resin or the like, they may accelerate the deterioration of the resin.

The present inventors conducted intensive research to solve the above-mentioned problems, and found that if titania sol is manufactured by a specific method, the problems associated with conventional titania sol can be solved.
It was discovered that a titania sol with excellent performance was obtained, and that modified titania particles produced from this titania sol had various excellent properties, leading to the completion of the present invention.

OBJECT OF THE INVENTION The present invention aims to solve the problems associated with the prior art as described above. The object of the present invention is to provide a method for producing a modified titania sol that is stable even when concentrated to a high concentration, does not cause precipitation even when mixed with an organic solvent, and has excellent coating properties.

Futamiko for λ The method for producing a modified titania sol according to the present invention is characterized by comprising the following steps (a) and (b).

(a) A step of preparing a titania sol precursor by adding hydrogen peroxide to a gel or sol of hydrous titanic acid to dissolve the hydrous titanic acid and heating the resulting solution in the coexistence of an inorganic compound; (b) A step of adding a silicon compound or a zirconium compound to the titania sol precursor to cause the silicon compound or zirconium compound to act on the titania sol precursor.

Shakugo Δ Hagiu Drunken Clothes The method for producing the modified titania sol according to the present invention will be specifically described below.

The method for producing titania sol according to the present invention includes (a) a step of preparing a titania sol precursor, and (b) a step of causing a silicon compound or a zirconium compound to act on the titania sol precursor. Each of these steps will be described below. (a) and (b) will be explained.

Step (a) First, a gel or sol of hydrous titanic acid is prepared by a conventionally known method. Hydrous titanate gel is
For example, 1q can be obtained by adding an alkali to an aqueous solution of a titanium salt such as titanium chloride or titanium sulfate to neutralize it. Hydrous titanate sol can also be produced by passing an aqueous solution of titanium salt through an ion exchange resin to remove anions.
It will be done. In order to prepare these sols or gels, not only the above methods but also a wide variety of conventionally known methods can be used. The hydrated titanic acid herein means titanium oxide hydrate or titanium hydroxide obtained by the method described above.

Next, hydrogen peroxide is added to the hydrated titanic acid gel, hydrated titanic acid sol, or a mixture thereof obtained as described above to dissolve the hydrated titanic acid to prepare a uniform aqueous solution. At this time, heat or tli ff as necessary.
- It is preferable to do so. At this time, if the concentration of hydrated titanic acid becomes too high, it will take a long time to dissolve the hydrated titanic acid, and an undissolved gel will precipitate, or the resulting aqueous solution will become too viscous, so this is not preferable. do not have.

Therefore, the TiO2 concentration is preferably about 10,000% by weight or less, preferably about 5% by weight or less.

If the amount of hydrogen peroxide to be added is 1 or more in a weight ratio of 1202/1-102, hydrous titanic acid can be completely dissolved. If the 1-12 o2/TiO2 ratio is less than 1, the hydrous titanic acid will not be completely dissolved and unreacted gel or sol will remain, which is not preferable. Also H O
The larger the /1-io2 ratio is, the faster the dissolution rate of hydrous titanic acid is, and the reaction is completed in a shorter time. However, if an excessive amount of hydrogen peroxide is used, a large amount of unreacted hydrogen peroxide will be present in the system. This is not preferable because it will remain and have an adverse effect on the next process. Therefore, it is preferable to use hydrogen peroxide in a case where the TiO2/TiO2 ratio is 1 to 6, preferably about 2 m6, and when hydrogen peroxide is used in such a case, the hydrous titanic acid is 0.5 It will completely dissolve in about 20 hours.

The reaction temperature at this time is desirably 50'C or more, preferably 70'C or more.

Next, an inorganic compound is mixed in an aqueous solution (titanic acid aqueous solution) in which 1q of hydrous butanoic acid obtained as above is dissolved, and the mixture is heated to 60° C. or higher, preferably 80° C. or higher,
Hydrolyzes titanic acid.

By doing this, 1 q of titania sol precursor in which titania particles are uniformly dispersed is obtained.

The inorganic compound used in the present invention is preferably A
Group Ⅰ of the periodic table such as 1st class, Group 1V such as Ti5Zr, 3i, 3m, Group V such as v, sb, Group Vl such as W, and F
A compound of one or more elements selected from Group Ⅰ such as e is used.

As the form of the compound, oxides, hydroxides, oxyacids, ixic acid salts, etc. are used.

These may be added in solid form or mixed as an aqueous solution. A preferred method uses gels or sols of these inorganic compounds. When using a sol, the average particle size of the dispersed particles is about 30 mμ or less, preferably about 157 mμ.
It is preferably nμ or less.

For example, in the case of silicon, silica gel, silica sol, or silicic acid solution is used. The citric acid solution referred to here is a solution of a low-grade compound of silicic acid obtained by dealkalizing an aqueous alkali silicate solution by an ion exchange method or the like.

The larger the amount of inorganic compounds mixed, the final 1q
The long-term stability and light resistance of the produced titania sol are increased, and a highly concentrated sol can be obtained. However, as the amount of the mixture increases, no increase in long-term stability or light resistance is observed.
This is not preferable because no increase in the effect of adding the inorganic compound is observed. Furthermore, it is observed that as the amount of the mixture decreases, the particle size of the titania particles obtained tends to increase. However, if the amount decreases too much, problems such as non-uniform particle size and agglomeration of particles will occur.

Taking the above into consideration, the inorganic compound to be mixed is the value of titanium oxide in the titanic acid aqueous solution converted to TiO2 and the type of the inorganic compound as oxide (MOx).
It is preferable that the ratio Tie2/MOx (width ratio) of the value converted to is in the range of 0.25 to 200. There are no particular restrictions on the method of mixing the titanic acid aqueous solution and the inorganic compound, and a predetermined amount of the titanic acid aqueous solution and the inorganic compound may be mixed at once, or a portion of the titanic acid aqueous solution and the inorganic compound may be mixed first. and heat as the reaction progresses.
The remainder of both may be added.

Alternatively, a method may be adopted in which the inorganic compound liquor and a portion of the titanic acid aqueous solution are first mixed and heated, and then the remaining titanic acid aqueous solution is added.

In addition, the timing of mixing the inorganic compound does not necessarily have to be after the hydrous titanic acid is dissolved in hydrogen peroxide; it may be mixed at the gel or sol stage before dissolving in hydrogen peroxide, or even when the hydrous titanic acid is mixed with the hydrogen peroxide. It may be mixed when preparing titanic acid glu or sol. In short, it is necessary that the above-mentioned inorganic compound be present when heating and hydrolyzing the titanic acid aqueous solution. When an aqueous titanic acid solution in which no inorganic compounds coexist is heated and hydrolyzed, some titania sol is formed even if the titania concentration is dilute, but the titania sol produced by 1q is extremely unstable, and for example, when it is concentrated, it no longer forms a sol. cannot exist and a precipitate is formed.

In the present invention, when using a titanium compound as an inorganic compound to be mixed with the titanic acid aqueous solution, a hydrous titanic acid gel or sol as the starting material of the present invention may be used, or the titanic acid aqueous solution of the present invention may be mixed without adding an inorganic compound. It is also possible to use a titania sol obtained by directly heating and hydrolyzing it. In these cases, it is preferable to completely dissolve the hydrous titanate glu or sol with hydrogen peroxide to form a titanic acid aqueous solution, and then mix the titanium compound described above.

The titania sol precursor thus obtained is also a titania sol in which titania particles are dispersed in a dispersion medium.

Step (b) Next, a silicon compound or a zirconium compound is added to the titania sol precursor obtained as described above,
A silicon compound or a zirconium compound is made to act on a titania sol precursor to produce 1 q of titania sol according to the present invention.

When preparing the titania sol precursor, titania (T i
02+ inorganic oxide) concentration is usually about 0.01 to 10
In the present invention, this titania sol precursor can be used as it is, or it can be concentrated and used in some cases. However, if the concentration of titania in the titania sol precursor becomes high, the titania particles will tend to aggregate and become unstable, so the titania concentration in the titania sol precursor is preferably about 7% by weight or less.

(1) Addition of a silicon compound The silicon compound added to the titania sol precursor is a silicic acid solution obtained by dealkalizing an aqueous alkali silicate solution with a cation exchange resin, or 1q by neutralizing an alkali silicate with an acid. A solution or dispersion of a silicon compound such as an alkoxide such as ethyl silicate or a hydrolyzate thereof is used. Commercially available silica sols can also be used, and in these cases, the particle size of the silica is preferably about 60° C. or higher.

Methods for adding a solution or dispersion of a silicon compound to a titania sol precursor include a method of gradually adding a solution or dispersion of a silicon compound while heating a liquid of a titania sol precursor, and a solution of a titania sol precursor and a silicon compound. Alternatively, the method may be one in which the mixture is mixed with the dispersion liquid all at once, or a method in which the mixture is heated, and the method should be selected depending on the titania concentration and the silica concentration in the silicon compound solution or dispersion liquid. If the titania concentration is relatively dilute, 1% by weight or less, there is no problem in mixing both at once, but if the titania concentration is high, 1% by weight or more, silica causes titania to coagulate. It is preferable to add the silica gradually, since a high silica concentration may cause aggregation or compatibility with the silica alone.

The temperature at the time of addition or mixing is usually preferably about 60° C. or higher to promote the reaction between the silicon compound and titania. However, when using alkoxides such as ethyl silicate, their hydrolysis rate is fast and colloidal particles of silica are easily generated in the mixed solution, so it is gradually heated at a relatively low temperature of about 40'C or less. A method is used in which the alkoxide is added and, after the addition is complete, the temperature is raised to about 60'C or higher to complete the reaction.

1) H in the mixed solution when adding the silicon compound is preferably neutral or alkaline from the viewpoint of stability of the titania sol precursor and the generated titania sol, and is usually about 6
-10.

As described above, when a silicon compound solution or dispersion is added, the amount of silica added when the silicon compound is converted to SiO2, and the TiO2 in the titania sol precursor.
The weight ratio s+02/T i O2 needs to be at least 0.03 in order to exhibit the effect of adding the silicon compound. However, as the amount of additive increases gradually, the original properties of titania (external ray shielding, high refractive index) are impaired, so the upper limit of the SiO/TiO2 value is approximately 0.
It is preferably about 7.

(2) Addition of zirconium compounds Zirconium compounds added to the titania sol precursor include acid salts such as zirconium chloride and zirconium sulfate, basic salts such as zirconyl ammonium carbonate, and zirconyl salts such as zirconyl oxychloride. Aqueous solutions or dispersions are used.

The method for adding such a zirconium compound to the titania sol precursor may be to mix the aqueous solution or dispersion of the zirconium compound into the titania sol precursor all at once, as in the case of silicon compounds, or to add the zirconium compound gradually to the titania sol precursor. May be added.

The ZrO2/TiO2 (weight ratio) when the zirconium compound added to the titania sol precursor is converted to ZrO2 is at least 0.05 or more and about 0.9 or less for the same reason as in the case of silicon compounds. It is preferable.

In addition, the solid content concentration of the titania sol precursor, temperature,
l) H is the same as in the case of silicon compounds.

The silica- or zirconia-modified titania sol obtained in this way can, if necessary,
can be adjusted to 6 to 10, and salts originating from starting materials such as silica or zirconia or from adjusting the effluent during the process can be removed by conventional means such as ultrafiltration and ion exchange. Generally speaking, titania sol modified with silica or zirconia is concentrated depending on the intended use, and known methods such as evaporation, ultrafiltration, etc. can be employed as the concentration method.

When an aqueous solution or dispersion of a silicon compound or an aqueous solution or dispersion of a zirconium compound is added to the titania sol precursor as described above, silicon oxide or hydroxide is formed on the surface of the titania particles contained in the titania sol precursor. Alternatively, zirconium oxides or hydroxides are adsorbed, or titania particles interact with these oxides or hydroxides,
Some changes occur in the properties of the titania particles. Such a change in the properties of titania particles includes, for example, a slight decrease in the surface activity of titania particles. For this reason, the titania particles obtained from the titania sol produced according to the present invention do not accelerate the deterioration of the resin when used, for example, as a filler for resins, and furthermore, when the titania particles are blended into cosmetics, they are not exposed to ultraviolet light. There is no change in the color tone of the particles.

Roughly speaking, the titania particles obtained from the titania sol produced according to the present invention have the same properties as the titania particles obtained from the titania sol precursor, such as ultraviolet shielding effect and high refractive index. The properties are largely intact. Moreover, the titania sol produced according to the present invention has excellent dispersibility as well as long-term stability and light resistance like the titania sol precursor.

It is also stable in a wide pH range and has a 30fffffi%
It has excellent properties such as being able to be concentrated to a high concentration (11) and being stable even when the proportion of the organic solvent in the dispersion medium is increased.

Effects of the Invention The titania sol produced by the present invention and the titania particles produced from the titania sol have the following excellent properties.

(1) Titania sol has excellent dispersibility, long-term stability, and light resistance, and is stable over a wide DH range.

(2) Titania sol can be concentrated to a high concentration.

(3) Titania sol is stable even if the proportion of the organic solvent in the dispersion medium is increased when the dispersion medium is replaced with an organic solvent.

(4) Titania sol has superior ultraviolet shielding effect and transparency compared to conventional titania fine particle dispersion.

(5) When titania particles obtained from titania sol are blended with a resin and used as a filler or as a coating agent, the deterioration of the resin is prevented and the durability and weather resistance of the resin are improved. do. Therefore, if it is incorporated into a plastic sheet for food packaging, for example, it can be stored for a longer period of time than conventional packaging materials.

(6) When titania particles obtained from titania sol are used as a surface coating agent for transparent substrates such as glass and Plus Deck, they have excellent adhesion to the substrate and have a high refractive index with excellent transparency and ultraviolet shielding effects. 1q of coating film is obtained.

(7) When titania particles obtained by 1q from titania sol are blended into cosmetics, cosmetics with excellent ultraviolet PQ shielding effect, finish, etc. can be obtained, and their deterioration (change in color tone, etc.) can be prevented.

EXAMPLES The present invention will be explained below with reference to Examples, but the present invention is not limited to these Examples.

Example 1 (Preparation of titania sol precursor) Titanium sulfate was dissolved in pure water, and an aqueous solution containing 0.4% by weight of TiO2 was prepared. While stirring this aqueous solution,
Gradually add 15% ammonia water to this aqueous solution, p)
'T8.5 white slurry liquid is Se1. This slurry was filtered and washed to obtain a cake of hydrous titanic acid gel having a solid content concentration of 9% by weight.

Add 5.55Nff of this cake to 33% hydrogen peroxide solution 6.
After adding 0.6Kg of pure water and 13.4Ky of pure water, the mixture was heated at 80°C for 5 hours to obtain 25Kg of a solution containing 2.0% by weight of T i O2. This butanoic acid aqueous solution was yellowish-brown and transparent, and had a pH of 8.1.

Next, 130 g of silica sol with a particle size of 7 mμ and a II degree of 15% by weight, the above titanic acid aqueous solution 9, and 191 K'J of pure water were mixed, and the mixture was heated at 95°C for 60 min.
heated for an hour. The solution was initially a yellow-brown liquid, but after 60 hours it became a milky-white transparent colloidal liquid.

The colloidal liquid thus obtained was concentrated by vacuum evaporation to obtain a titania sol precursor with a solid content of 1.1%.
To! I got j.

(Treatment with silicon compound) A sodium silicate solution with a SiO2 permeability of 23.8% by weight and a 5i02/Na2O molar ratio of 3.0 was diluted with pure water to form a solution of 3.2% by weight.
Dilute sodium silicate of % weight was adjusted, and this was passed through a cation exchange resin (Diaion 5K-18 manufactured by Mitsubishi Chemical Industries, Ltd., manufactured by Mitsubishi Chemical Industries, Ltd.) FM, which had been filled in a column in advance, and then
A 3.0% by weight silicic acid solution was obtained.

Next, sodium hydroxide was added to 2,000 g of the titania sol precursor to reduce 1)H of the titania sol precursor to 9.7
After adjusting to 95°C.

While keeping the titania sol precursor at this temperature, 4 to 10 g of the above silicic acid solution diluted to 0.5% by weight with pure water was gradually added over 12 hours, and after the addition was completed, the titania sol precursor was kept at this temperature for about 1 hour. was held. When the obtained dilute titania sol was concentrated by vacuum evaporation, titania sols as shown in Table 1 were obtained.

Example 2 In Example 1, the amount of added silicic acid liquid was 8809,
A titania sol as shown in Table 1 was obtained in the same manner as in Example 1 except that the addition time was 30 hours.

Example 3 A titania sol as shown in Table 1 was obtained in the same manner as in Example 1, except that the silicic acid solution 22409 was added over 38 hours.

Example 4 Dilute ammonia water was added to 2000 g of the titania sol precursor obtained in 1q in Example 1 to adjust I) Hlo to 8.

To this solution, ethyl silica 1 to 12.4y (14.5% by weight as S102) diluted with ethylic alcohol and 9
．． Add 13.1g of 4% ammonia water through separate addition ports,
Addition took place over 19 hours at 0'C. After the addition was completed, 0.1N hydrochloric acid was added to the reaction solution to adjust pl-1 to 9.2, and then 6
It was heated to 0'C and aged for 1 hour.

The obtained titania sol was subjected to ultrafiltration to remove ethanol, ammonia, and 41 in the solvent, and then concentrated by vacuum evaporation to obtain a titania sol as shown in Table 1.

Example 5 Zirconyl ammonium carbonate (trade name Zircosol AC)
1 Daiichi Kigenso Kagaku Kogyo Co., Ltd.) diluted with pure water
The rO2 was adjusted to 0.5%.

On the other hand, the titania sol precursor 2000 obtained in Example 1
9 was heated to 95° C., and while maintaining this temperature, 630 g of the above zirconyl ammonium carbonate solution was gradually added to the titania sol precursor over 25 hours. After the addition was complete, the temperature was maintained at 95°C for 1 hour. The ammonium carbonate in the solvent was washed from the 1q titania sol by ultrafiltration, and then concentrated by vacuum evaporation to obtain the titania sol shown in Table 1.

Example 6 After mixing 1.0 Kg of the titanic acid aqueous solution prepared in Example 1 with 200 Ky of pure water, the mixture was heated at 95°C for 2 hours.
1 q of titania sol containing 0.01% by weight as TiO2 was prepared. Hydrolysis was carried out under the same conditions as in Example 1, except that this sol was used in place of the silica sol in Example 1, to obtain a titania sol precursor.

Using this titania sol precursor, treatment was carried out with the same citric acid solution as in Example 1 and the same as in Example 1 to obtain titania sol 1 shown in Table 1.

Comparative Example 1 The cake of hydrous titanic acid gel obtained in Example 1 was diluted with pure water to obtain a suspension having a Ti02i looseness of 2.0% by weight. To this, 0.1N hydrochloric acid was gradually added until it became a sol. After the obtained sol was stabilized at 80'C for 1 hour, water was evaporated under reduced pressure to obtain a concentrated sol by peptization.

This sol could be concentrated to 20% by weight, but the pH h;
The sol contained 2.1% by weight of chlorine ions, which was as low as 1.7%.

Test Example 1 The titania sols prepared in Examples 1 to 4 and Comparative Example 1 were tested for solvent substitution with isopropyl alcohol (IPA) and stability of titania powder obtained from these sols. The results shown in 1 are 19. The respective test methods are as follows.

(1) Solvent replacement stability Each concentrated sol was diluted with water to 10ffi1%, and using ultrafiltration method, the IPAIQ degree in the total solvent was 40 m%, 70 m%.
The solvent was replaced until the concentration reached 90% by weight, and the presence or absence of a precipitate was observed.

In the table, the O mark indicates no change, and the X mark indicates the occurrence of a gel-like precipitate.

After evaporating Monsue Gentari Yusol to dryness, it was dried at 110℃ for 12 hours to form T.
iO2 powder is 17.

0.2y of the above powder was added to 1M of a 100% solution of squalane or glycerin, mixed well, and then irradiated with ultraviolet rays for 16 hours using an ultraviolet lamp for a weather meter.
I saw a change in color tone.

Test Example 2 The titania sols obtained in Example 1, Example 3, and Comparative Example 1 were each taken at a solid content of 20 g, and acrylic water-based resin Aron 104 (manufactured by Toagosei Chemical Industry Co., Ltd., concentration 30) was added.
%) 709.

After mixing the isocyanate curing agent Coronato IL (manufactured by Nippon Polyurethane Kogyo Co., Ltd. >1.5 g) with this, it was applied onto a glass plate and dried at 130'C for 30 minutes to obtain a coating film.

The weather resistance of this coating film was measured using a weather meter (Suga Test Instruments).
The yellowing degree (in NBS units) of the resin was tested by measuring the degree of yellowing (in NBS units). The results are shown in Figure 1.

Test Example 3 The titania sol produced by 1q in Example 1 was treated with a TiO2 waterfall degree of 0.
The absorbance in the ultraviolet region (approximately 400 nm or less) and the light transmittance in the visible light region (approximately 4001 m or more) were measured. As a comparative example, fine particle titania (Aerosil, P-25, manufactured by Degutsu Isu Co., Ltd.) obtained by gas-phase oxidation of titanium chloride was dispersed in water, and a dispersion liquid was adjusted to T+021 degrees and the same 0.005 weight ω%. The absorbance and light transmittance of the sample were measured. The results are shown in FIG. In the figure, the 1 tftt line shows the light transmittance of the titania sol of the present invention, - is the curve showing the light transmittance of the titania sol of the comparative example, and O is the curve showing the absorbance of the titania sol of the present invention. , O' is a curve showing the absorbance of the titania sol of the comparative example.

In addition, the measurement was performed using a spectrophotometer (Hitachi Separation, Model 330).

[Brief explanation of the drawing]

Figure 1 shows 1rf from the titania sol produced by the present invention.
FIG. 2 is a diagram showing the weather resistance of a resin when ditania particles are added to the resin. FIG. 2 is a diagram showing the absorbance and light transmittance of the titania sol of the present invention and a commercially available titania fine particle dispersion. Agent Patent Attorney Shunichi Suzuki Figure 1 Time (HR8)

Claims (2)

[Claims] (1) Method for producing a stable modified titania sol consisting of the following steps: (a) Hydrogen peroxide is added to a gel or sol of hydrous titanic acid to dissolve the hydrous titanic acid, and the resulting solution is mixed with an inorganic compound. (b) adding a silicon compound or a zirconium compound to the titania sol precursor to cause the silicon compound or the zirconium compound to act on the titania sol precursor; (2) The silicon compound or zirconium compound is Si
At least 0.0 as O_2/TiO_2 (weight ratio)
3 or at least 0.05 as ZrO_2/TiO_2 (weight ratio).