JPH0615408B2 - Surface-modified titanium oxide ultrafine particles - Google Patents

Description

TECHNICAL FIELD The present invention relates to surface-modified titanium oxide ultrafine particles,
More specifically, the present invention relates to surface-modified ultrafine titanium oxide particles useful as an ultraviolet deterioration inhibitor, an ultraviolet shielding sheet and film, a sunscreen paint, and the like.

[Problems to be Solved by Prior Art and Invention]

Titanium oxide is widely used in the fields of cosmetics, paints, etc. because it has excellent weather resistance and has a high hiding power. However, titanium oxide fine particles have a problem that they are not dispersed in an organic solvent. Therefore, in the future, titanium oxide, which is surface-modified and easily dispersed in an organic solvent or resin, is required in order to develop a wide range of applications.

As a surface modification method, a crystalline granular titanium oxide is treated with a silane coupling agent having an amino group (eg, aminoalkoxysilane, polyethyleneimine-containing silane, etc.), and then a hydrophobizing agent (eg, silazane, lower alkylalkoxysilane, A method of treating with a silicone oil, a hydrogenated silicone oil, etc. (JP-A-58-184505) and a method of treating crystalline granular titanium oxide with hydroxylamine or cycloimine and then treating with the above-described hydrophobizing agent. (JP-A-59-137305, etc.) have been proposed.

However, the conventional surface modification method as described above is unsuitable for the recently developed amorphous and granular titanium oxide ultrafine particles (Japanese Patent Laid-Open No. 61-201604), and sufficient modification is required. It turned out that the effect could not be obtained.

Therefore, the present inventors have conducted earnest studies to develop amorphous and spherical ultrafine particulate titanium oxide having high dispersibility in organic solvents and resins and having a high specific surface area.

[Means for solving problems]

As a result, it was found that the spherical amorphous titanium oxide ultrafine particles having a high specific surface area were treated as a raw material with a specific surface modifier and had the above-mentioned desired physical properties. . The present invention has been completed based on such findings.

That is, the present invention is an average particle surface-modified with one or more compounds selected from the group consisting of anionic or nonionic organotitanium compounds, anionic surfactants and anionic or nonionic organosilicon compounds. Diameter 100 ~
The present invention provides ultrafine amorphous spherical titanium oxide particles having a surface area of 1000Å and a specific surface area of 50 to ²⁰⁰ m ² / g.

The surface-modified titanium oxide ultrafine particles in the present invention,
It is amorphous and spherical, and has an average particle size of 100 to 1000Å and a specific surface area of 50 to ²⁰⁰ m ² / g. Such surface-modified titanium oxide ultrafine particles may be obtained by subjecting amorphous and spherical titanium oxide ultrafine particles having the same or slightly larger specific surface area as those described above to a raw material and subjecting this to surface treatment with the above-mentioned surface modifier. can get. Here, the titanium oxide ultrafine particles to be surface-modified can be produced by various methods, but preferably, for example, by the method disclosed in JP-A-61-201604.
That is, titanium oxide before surface modification is obtained by vaporizing or atomizing a volatile titanium compound (for example, titanium tetraisopropoxide), and then decomposing it under heating to form titanium oxide ultrafine particles, and immediately after decomposing the titanium oxide. What is produced by cooling to a temperature at which the ultrafine particles do not coalesce again is applied.

The surface-modified titanium oxide ultrafine particles of the present invention comprises the above amorphous spherical titanium oxide ultrafine particles composed of an anionic or nonionic organotitanium compound, an anionic surfactant and an anionic or nonionic organosilicon compound. The surface treatment is performed by using one or more compounds selected from the group as a surface modifier.

Here, as the anionic or nonionic organic titanium compound, a titanium coupling agent, for example, an organic titanium compound having a -Ti-O bond, such as isopropyltriisostearoyl titanate, isopropyltridodecylbenzenesulfonyl titanate, isopropyltris (dioctylpyroyl). Phosphate) titanate, tetraisopropyl bis (dioctyl phosphite) titanate, tetraoctyl bis (ditridecyl phosphite)
Citatate, tetra (2,2-diallyloxymethyl-
1-butyl) bis (ditridecyl) phosphite titanate, bis (dioctylpyrophosphate) oxyacetate titanate, bis (dioctylpyrophosphate) ethylene titanate, isopropyl trioctanoyl titanate, isopropyl dimethacryl isostearoyl titanate, isopropyl isostearoyl diacrylic titanate , Isopropyl tri (dioctyl phosphate) titanate, isopropyl tricumyl phenyl titanate, dicumyl phenyloxyacetate titanate, diisostearoyl ethylene titanate and the like.

When the organic titanium compound is used, it is usually used in a proportion of 5% by weight or more, preferably 5 to 20% by weight, based on the raw material titanium oxide (dry weight). If the amount of the organic titanium compound used is too small, the effect of hydrophobization (lipophilicity) does not appear, and conversely, if it is too large, the effect is saturated, which is not economical.

In order to modify the surface of titanium oxide with an anionic or nonionic organotitanium compound, the organotitanium compound is added to the compound 1
After being dissolved in an organic solvent having a weight ratio of 0.5 to 50, it is mixed with titanium oxide at room temperature in the above ratio,
It may be stirred for 5 to 60 minutes to obtain powdery or slurry-like treated titanium oxide, which may be dried at room temperature to 110 ° C. for 3 to 24 hours. Here, as the organic solvent, hexane, acetone, ethanol, toluene or the like can be used.

The anionic surfactant used in the present invention is preferably a fatty acid alkali salt. Here, the fatty acid may have a straight chain or a branched chain, and may be a monobasic acid or a polybasic acid having two or more dibasic acids. As the anionic surfactant, a straight-chain fatty acid alkali salt is preferable, and specific examples thereof include sodium laurate, sodium myristate, sodium palmitate, sodium stearate and the like.

When an anionic surfactant is used, it is usually used in a proportion of 5% by weight or more, preferably 5 to 20% by weight of the raw material titanium oxide (dry weight). If this amount is too small, the effect of hydrophobization (lipophilicity) does not appear,
On the other hand, if the amount is too large, the effect will be saturated, which is not economical.

When surface modification is performed using an anionic surfactant,
The surface-active agent 1 is dissolved in water at a weight ratio of 0.5 to 50, stirred for 10 to 120 minutes, and then mixed with titanium oxide in the above ratio to give a granular or slurry treatment. Titanium oxide may be obtained and dried at room temperature to 110 ° C. for 3 to 24 hours. The treated titanium oxide in a slurry form may be suction filtered, washed with water having a weight ratio of 1 to titanium oxide of 5 to 50, and dried at room temperature to 110 ° C. for 3 to 24 hours.

Examples of the anionic or nonionic organosilicon compound used in the present invention include silane coupling agents such as the above organosilicon compounds having a hydrolyzable group bonded to a silicon atom. Here, examples of the hydrolyzable group include chlorine, an alkoxy group, and an alkanoyl group.
Specific examples of the organosilicon compound that can be used in the present invention include the following compounds.

_{CH 2 = CHSiCl 3 CH 2 =} CHSi (OC 2 H 5) 3 CH 2 = CHSi (OCH 3) 3 CH 2 = CHSi (OC 2 H 4 OCH 3) 3 CH 2 = CCH 3 COOC 3 H 6 Si (OCH ₃ ) ₃ CH ₂ ═C (CH ₃ ) COOC ₃ H ₆ Si (OC ₂ H ₄ OCH ₃ ).
_{3 ClC 3 H 6 Si (OCH 3} ) 3 HSC 3 H 6 Si (OCH 3) 3 HSC 3 H 6 Si (OC 2 H 5) 3 C 6 H 5 Si (OC 2 H 5) 3 polymer silane OCnC ₃ H _{6 Si (OC 2 H 5)} 3 n-C 8 H 17 Si (OC 2 H 5) 3 Polyalkylene oxide silane Anionic or nonionic antistatic silane When an anionic or nonionic organosilicon compound is used, it is usually added in an amount of 5% by weight or more, preferably 5 to 40% by weight based on the starting titanium oxide (dry weight). If this addition amount is too small, the effect of making hydrophobic (lipophilic) will not be achieved, and if it is too large, the effect will be saturated,
Not economical.

When the surface is modified with the above organosilicon compound,
The same operation as in the case of using the organic titanium compound may be performed.

The case where the anionic or nonionic organotitanium compound, the anionic surfactant or the anionic nonionic organosilicon compound is used alone is as described above, but the titanium oxide is surface-modified by using two or more of these. You can also do it. When the surface modification treatment is carried out using two or more kinds, it may be carried out according to the above-mentioned single operation.

〔Example〕

Next, a more detailed description will be given with reference to Examples and Comparative Examples of the present invention.

Example 1 1.4 g of bis (dioctylpyrophosphate) oxyacetate titanate was placed in a 200 ml beaker and dissolved in 35 ml of hexane. This solution has an average particle size of 20
Add 7 g (dry basis) of spherical amorphous titanium oxide (unmodified surface) with 0Å and a specific surface area of 130 m ² / g, and add 10 at room temperature.
Stir for minutes. Since it became a slurry, the slurry was transferred to a glass dish and dried in air at 110 ° C. for 3 hours. After drying, the lumped titanium oxide was ground in a porcelain mortar to give a powder. When the obtained surface-modified titanium oxide was evaluated by the lipophilicity evaluation method described later, the lipophilicity was 52%, and no particles precipitated even when left in toluene. The modified titanium oxide had an average particle diameter of 200Å and a specific surface area of 90 m ² / g.

In this experiment, the same titanium oxide was treated with various additions of bis (dioctylpyrophosphate) oxyacetate titanate (modifier), and the lipophilicity of the obtained surface-modified titanium oxide was measured, The relationship between the amount of modifier added and the degree of lipophilicity is shown in FIG.

Lipophilicity evaluation test Put 50 ml of distilled water in a 100 ml beaker, and put 0.2 g of lipophilic fine powder sample to be further evaluated. If the sample is sufficiently lipophilic, it is completely floating on the water surface. To the floating water of this sample, methanol is dripped from a buret whose tip is immersed in water while stirring with a small magnetic stirrer. As methanol is added, the sample powder floating on the water surface becomes wet and disperses in water. Read the amount of methanol added when the sample is completely floating and completely wet. Measured value is a
In ml, the lipophilicity is defined by the following formula.

Therefore, the larger the lipophilicity is, the higher the concentration of the methanol aqueous solution is, and the higher the lipophilicity is, the higher the lipophilicity is.

Example 2 A surface-modified titanium oxide was obtained in the same manner as in Example 1 except that hexane was 7 ml and the drying step and the crushing step were omitted.
The lipophilicity was 51%, and no particles were precipitated when left in toluene.

Example 3 70 ml of ion-exchanged water was placed in a 200 ml beaker, and then 7 g of titanium oxide used in Example 1 was dispersed by stirring with a stirrer. Subsequently, 1.4 g of sodium laurate was added, and the mixture was stirred at room temperature for 30 minutes. Next, suction filtration, washing with water (70 ml of deionized water, room temperature), and then at 110 ° C. for 3
Dried for hours. The dried product was pulverized to obtain surface-modified titanium oxide. Its lipophilicity was 59% and the particles precipitated after standing.

Example 4 4 ml of ion-exchanged water was placed in a 200 ml beaker, and then 0.185 g of sodium laurate was added and dissolved. Further, 4 g of the titanium oxide used in Example 1 was added and stirred for 10 minutes to obtain powdered treated titanium oxide. Next, it was dried in air at 110 ° C. for 3 hours to obtain a surface-modified titanium oxide. The lipophilicity was 35%. The surface-modified titanium oxide has an average particle size of 200Å and a specific surface area of 95.
It was m ² / g.

Example 5 A surface-modified titanium oxide was obtained in the same manner as in Example 3 except that evaporation and drying were performed without suction filtration and washing with water. The lipophilicity was 58%.

Example 6 The obtained 35 ml was placed in a 200 ml beaker, and 2.8 g of vinyltriethoxysilane was added and dissolved. Titanium oxide used in Example 1 was added to the solution, stirred at room temperature for 10 minutes, and then treated in the same manner as in Example 1. The lipophilicity was 27%. The surface-modified titanium oxide had an average particle size of 200Å and a specific surface area of 80 m ² / g.

Comparative Example 1 The same operation as in Example 3 was carried out except that 1.4 g of polyoxyethylene sorbitan monostearate, which was a nonionic surfactant, was used in place of sodium laurate.
A surface-modified titanium oxide was obtained. The lipophilicity was 0%. The average particle size of this surface-modified titanium oxide is 200
Å, the specific surface area was 110 m ² / g.

Application Example 1 To 90 parts by weight of polystyrene, 10 parts by weight of the surface-modified granular amorphous titanium oxide ultrafine particles obtained in Example 1 were added, and 10 × 4 at 250 ° C. with a minimax molding machine.
A 0 mm test piece was prepared. Further, this test piece was formed into a sheet-like test piece having a thickness of 200 μm at 250 ° C. by a press molding machine. The absorbance at 500 nm of this test piece was 0.30.

Comparative Example 2 A test piece was prepared in the same manner as in Application Example 1 except that untreated spherical amorphous titanium oxide ultrafine particles were used instead of the surface-modified spherical amorphous titanium oxide ultrafine particles. 500n
When the absorbance at m was measured, the absorbance was 0.40, and the transparency was lower than in Application Example 1.

Comparative Example 3 As the titanium oxide, mixed crystalline anatase-type and rutile-type crystalline rice titanium oxide (P-25 manufactured by Degussa Co.) was used, and this was treated with bis (dioctylpyrophosphate) oxyacetate titanate in the same manner as in Example 1. Processed to produce surface-modified titanium oxide. A test piece was prepared in the same manner as in Application Example 1 except that the thus-prepared surface-modified granular titanium oxide was used, and the absorbance was measured and found to be 0.50, indicating that the test piece was cloudy.

〔The invention's effect〕

The surface-modified titanium oxide ultrafine particles of the present invention are amorphous, spherical, have a high specific surface area, and have high surface hydrophobicity. That is, according to the present invention, surface-modified titanium oxide ultrafine particles having remarkably improved dispersibility in an organic solvent or a resin are provided.

Therefore, the surface-modified titanium oxide ultrafine particles of the present invention,
It is expected to be effectively used as an excellent UV deterioration inhibitor for UV-shielding plastic sheets and films and sunscreen paints for automobiles.

[Brief description of drawings]

FIG. 1 is a graph showing the relationship between the amount of modifier added and the degree of lipophilicity of surface-modified titanium oxide in Example 1.

Claims (4)

[Claims] 1. Average particles surface-modified with one or more compounds selected from the group consisting of anionic or nonionic organotitanium compounds, anionic surfactants and anionic or nonionic organosilicon compounds. Diameter 100-100
Amorphous spherical titanium oxide ultrafine particles having 0Å and a specific surface area of 50 to ²⁰⁰ m ² / g. 2. The ultrafine particles according to claim 1, wherein the anionic or nonionic organotitanium compound is an organotitanium compound having a —Ti—O— bond. 3. The ultrafine particles according to claim 1, wherein the anionic surfactant is an aliphatic alkali salt. 4. The ultrafine particles according to claim 1, wherein the anionic or nonionic organosilicon compound is an organosilicon compound having a hydrolyzable group bonded to a silicon atom.