JP4641212B2 - Composite oxide ultrafine particles and process for producing the same - Google Patents

Description

  The present invention is a composite oxide ultra-high refractive index average particle diameter of 1 to 100 nm which is excellent in light resistance, weather resistance, transparency, dispersibility and the like useful for applications such as optical materials, hard coat materials, and resin lenses. The present invention relates to fine particles and a method for producing the same.

  Corresponding to the recent increase in the refractive index of plastic lenses, the hard coat film applied on the plastic lens has the disadvantage that a striped pattern occurs unless it has a high refractive index. Is required. Similarly, high refractive index ultrafine particles excellent in dispersion stability, scratch resistance, surface hardness, abrasion resistance, transparency, heat resistance, light resistance, weather resistance, UV shielding, etc., and the sol solution is an antireflection film , Plastic deterioration prevention additive, cosmetic additive, glasses lens, camera lens, automotive window glass, plasma display, liquid crystal display, EL display, optical filter and other optical members, metal materials, ceramic materials, glass materials, plastics It is also required in the field of products such as surface treatment agents such as materials, electronic materials such as dielectric materials and piezoelectric materials, photocatalysts, and water repellents. Since high dispersibility and transparency are required for use in such various applications, the inorganic oxide is desirably ultrafine particles.

  A typical example of such an inorganic oxide is titanium oxide. Titanium oxide is particularly suitable as a high refractive index agent because of its particularly high refractive index and high transparency. Titanium oxide includes rutile type and anatase type as typical crystal types, and so far, as a metal oxide ultrafine particle sol solution for increasing the refractive index, refractive index no = 2.56, ne = 2.49. A material mainly composed of anatase-type titanium oxide ultrafine particles having (no: refractive index with respect to ordinary light, ne: refractive index with respect to extraordinary light) (edited by the Chemical Society of Japan, Chemical Society of Japan) is mainly used. On the other hand, the rutile type titanium oxide has a refractive index no = 2.61 and ne = 2.9, and is superior in an optical characteristic such as a high refractive index and ultraviolet absorption compared to the anatase type. Attempts to synthesize the rutile-type titanium oxide ultrafine particles and the sol liquid are actively made. However, the rutile type titanium oxide ultrafine particles and sol liquid that can be used industrially have not been obtained yet. For example, as reported in Jpn. J. Appl. Phys., 37, 4603 (1998), aggregates having an aggregate particle diameter of 200 to 400 nm in which long-fiber rutile titanium oxide is gathered are formed.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that the tin compound used as a sintering agent prevents long fiber formation and also prevents aggregation. It has already been found that a sol solution having excellent properties can be obtained.

  On the other hand, when these titanium oxide ultrafine particles are used for optical materials, hard coat materials, resin lenses, etc., particularly when used in combination with organic substances such as resins, the light resistance may be inferior due to the photocatalytic action of titanium oxide. I know it. In other words, since electron-holes generated by light absorption of titanium oxide cause organic matter decomposition, the scratch resistance, surface hardness, abrasion resistance, transparency, heat resistance, light resistance, weather resistance, ultraviolet shielding properties, etc. are reduced. It has become a big problem.

  Similarly, ultra-fine particles of high refractive index with excellent light resistance and weather resistance, sol solution is plastic deterioration prevention additive, cosmetic additive, camera lens, automotive window glass, plasma display, liquid crystal display, EL display, optical It is also required in the product field such as optical members such as filters, metal materials for adjusting the refractive index, ceramic materials, glass materials, plastic materials and the like.

  At present, for the purpose of improving the light resistance of optical materials, hard coat materials, resin lenses and the like containing such anatase-type titanium oxide ultrafine particles, for example, anatase-type titanium oxide and a metal oxide as described in Patent Document 1 are used. Composite ultrafine particles, ultrafine particles obtained by coating anatase-type titanium oxide with a metal oxide, and sol solutions thereof are applied.

  These are all aimed to inactivate anatase-type titanium oxide ultrafine particles by metal oxide coating. Thus, light resistance is improved by coat | covering a titanium oxide ultrafine particle with a metal oxide. However, since titanium oxide used is anatase type, the refractive index is about 2.5, and when coated with a metal oxide to improve light resistance, the refractive index is greatly reduced. The refractive index is lower than that of the original anatase-type titanium oxide, and the effect of improving the refractive index of optical materials, hard coat materials, resin lenses, etc. is low. Even if the amount of metal oxide to be coated is reduced and the refractive index is increased, the light resistance becomes insufficient, and scratch resistance, surface hardness, abrasion resistance, transparency, heat resistance of optical materials, hard coat materials, resin lenses, etc. , Light resistance, weather resistance, ultraviolet shielding properties and the like are problems.

On the other hand, the rutile type titanium oxide having a higher refractive index than the conventional anatase type titanium oxide, as described above, has no ultrafine particles and sol liquid that can be used.
JP 2001-123115 A

  The present invention is a composite oxide ultra-high refractive index average particle diameter of 1 to 100 nm which is excellent in light resistance, weather resistance, transparency, dispersibility and the like useful for applications such as optical materials, hard coat materials, and resin lenses. It is an object of the present invention to provide fine particles, a sol liquid, and a production method thereof.

  In order to solve the above-mentioned problems, as a result of intensive studies, the present inventors found that tin-modified rutile titanium oxide ultrafine particles and sol liquid excellent in transparency and dispersibility were used as nuclear ultrafine particles. By coating with antimony oxide and silicon oxide, composite oxide ultrafine particles having a high refractive index excellent in light resistance, weather resistance, transparency, dispersibility, etc. and an average particle diameter of 1 to 100 nm, that is, composite oxide The inventors have found that coated tin-modified rutile-type titanium oxide ultrafine particles can be obtained, and have completed the present invention.

More specifically,
1. In the presence of a tin compound having a molar ratio of tin to titanium (Sn / Ti) of 0.001 to 2, a titanium compound aqueous solution having a Ti concentration of 0.07 to 5 mol / l is reacted in a pH range of −1 to 3. The obtained Sn / Ti composition molar ratio is 0.001 to 0.5, and the rutile-type titanium oxide ultrafine particles having a minor axis of crystal diameter and a major axis of 2 to 20 nm are used as core fine particles, and the antimony oxide. A composite oxide ultrafine particle comprising a coating layer containing a silicon oxide and a minor axis of crystal diameter and a major axis of 2 to 20 nm.
2. The weight ratio of coating layer / nuclear fine particles is 1/99 to 90/10, and the weight ratio of antimony oxide / silicon oxide contained in the coating layer is 100/1 to 1/50. 2. The composite oxide ultrafine particles as described in 1 above.
3. 3. The ultrafine particles according to 1 or 2 above, wherein the refractive index is 1.5 to 2.8.
4). Ultrafine particles characterized in that the average aggregate particle diameter of crystals of the ultrafine particle aggregates comprising the ultrafine particles according to any one of 1 to 3 is 10 to 100 nm.
5. A sol obtained by dispersing the ultrafine particles according to any one of 1 to 4 in water or an organic solvent.
It is about.

  The composite oxide ultrafine particles of the present invention, that is, the composite oxide-coated tin-modified rutile-type titanium oxide ultrafine particles, cannot be achieved by the conventional production method, and the high refractive index ultrafine particles cannot be obtained by the anatase type. A sol solution can be provided. The composite oxide ultrafine particles of the present invention have high refractive index and ultraviolet shielding properties as rutile titanium oxide by coating tin-modified rutile titanium oxide ultrafine particles with antimony oxide and silicon oxide. The photocatalytic property is effectively suppressed. By using the resulting composite oxide ultrafine particles and sol solution, an antireflection film excellent in scratch resistance, surface hardness, abrasion resistance, transparency, heat resistance, weather resistance, ultraviolet shielding properties, etc., Plastic deterioration prevention additive, cosmetic additive, eyeglass lens, camera lens, automotive window glass, plasma display, liquid crystal display, EL display, optical filter and other optical members, metal material, ceramic material, glass material, plastic material It can be suitably used for products such as surface treatment agents such as dielectric materials, electronic materials such as piezoelectric materials, and water repellents.

  Hereinafter, the present invention will be described in more detail.

  The present invention provides a titanium compound aqueous solution having a Ti concentration of 0.07 to 5 mol / l in the coexistence of a tin compound having a molar ratio of tin to titanium (Sn / Ti) of 0.001 to 2, and a pH of −1 to 3. Rutile-type titanium oxide ultrafine particles having a Sn / Ti composition molar ratio of 0.001 to 0.5 and a minor axis of crystal diameter and a major axis of 2 to 20 nm obtained as a result of the reaction are used as core fine particles. And a composite oxide ultrafine particle characterized by comprising a coating layer containing antimony oxide and silicon oxide and having a minor axis of crystal diameter and a major axis of 2 to 20 nm.

  First, tin-modified rutile titanium oxide ultrafine particles, which are core fine particles, will be described.

  The tin-modified rutile-type titanium oxide ultrafine particles of the present invention are titanium compounds having a Ti concentration of 0.07 to 5 mol / l in the presence of a tin compound having a molar ratio of tin to titanium (Sn / Ti) of 0.001 to 2. Tin-modified rutile-type titanium oxide ultrafine particles obtained by reacting an aqueous solution in the range of −1 to 3, the Sn / Ti composition molar ratio of the ultrafine particles being 0.001 to 0.5, and A tin-modified rutile-type titanium oxide ultrafine particle, characterized in that the minor axis and the major axis of the crystal diameter are 2 to 20 nm, and the average aggregate particle diameter of crystals of the ultrafine particle aggregate is 10 to 100 nm.

  The crystal diameter referred to here is a so-called primary particle diameter, and is expressed by the lengths in the a and c axis directions as described in Chemical Handbook Revision 3 (Basic Edition Maruzen Co., Ltd.). In this specification, they are called a short axis and a long axis, respectively. Moreover, the average aggregated particle diameter represents a particle diameter obtained by aggregating primary particles.

  First, a method for producing tin-modified rutile titanium oxide ultrafine particles will be described.

The tin compound used in the present invention is not particularly limited, but specifically, for example, a tin salt compound such as tin chloride, tin nitrate, tin sulfate, stannate, or an oxide, hydroxide, metal Preferred examples include tin compounds selected from tin and the like.
The titanium compound used in the present invention is not particularly limited. Specifically, for example, titanium chloride oxide, titanium sulfate, titanium nitrate, titanium alkoxide, hydrated titanium oxide (a titanium compound in advance under alkaline conditions). Preferred examples include titanium compounds selected from such as hydrolyzed ones).

  First, a tin compound is added to an aqueous solution, and a titanium compound is added thereto. The tin compound and the titanium compound may be added at the same time, or either one may be first. Moreover, the form of a mixed compound may be sufficient. The reaction medium is preferably water, but may be an organic solvent such as alcohol or a mixed medium of water and an organic solvent.

  The amount of tin compound used in the reaction as a modifier for controlling crystal growth of rutile titanium oxide is such that the molar ratio of tin to titanium (Sn / Ti) is 0.001 to 2, preferably 0.01 to 1. It is desirable. If the tin amount is less than the above range, rutile-type titanium oxide ultrafine particles are produced, but the crystal diameter and aggregated particle diameter are increased, and therefore the dispersibility may be deteriorated. In addition, the transparency of optical materials, hard coat materials, resin lenses, etc. may be reduced. Further, even if the amount is larger than the above range, it is possible to synthesize the titanium oxide ultrafine particles having the rutile type, but the time required for the reaction becomes long. In this case, a large amount of tin compound is contained in the rutile type titanium oxide ultrafine particles. There is a possibility that a product with attached will be obtained. On the other hand, if it is larger than this, the amount of the residual tin compound increases, and the particle refractive index may decrease.

  The Ti concentration in the reaction solution is 0.07 to 5 mol / l, preferably 0.1 to 1 mol / l. When the Ti concentration is lower than the above range, there is a possibility that anatase-type and rutile-type mixed titanium oxide ultrafine particles may be produced even if a tin compound is added in the range of 0.01 to 0.03 as Sn / Ti (molar ratio). is there. Similarly, at a Ti concentration lower than the above range, if a tin compound is added in a range larger than 0.03 as Sn / Ti (molar ratio), there is a possibility that titanium oxide-tin oxide mixed ultrafine particles having rutile tin oxide are generated. is there.

  The pH of the reaction solution is desirably −1 to 3. Adjust with hydrochloric acid or nitric acid as necessary. When the reaction is carried out under a condition where the pH is greater than 3, anatase-type titanium oxide is obtained in the case where no tin compound is added, and in order to avoid this, a tin compound is added to obtain a rutile structure. There is a possibility that foreign substances other than rutile-type titanium oxide are produced.

  Regarding the reaction temperature, the Ti concentration and pH may be in the above ranges, and there is no particular limitation, but preferably −10 to 100 ° C., more preferably 20 to 60 ° C. is recommended. Although the reaction completion time is determined depending on the reaction temperature, it is usually carried out in 0.5 to 10 hours.

  The amount of tin compound contained in the tin-modified rutile-type titanium oxide ultrafine particles produced by the above reaction is preferably Sn / Ti molar ratio = 0.001 to 0.5. If the amount of tin is made smaller than the above range, the particle diameter of the rutile titanium oxide ultrafine particles becomes large and the dispersibility may be deteriorated. Also, if the amount is larger than the above range, crystal growth and aggregation can be controlled more efficiently, and ultrafine particles with a small particle diameter can be obtained, but a rutin-type titanium oxide ultrafine particle with a large amount of tin compound attached can be obtained. As a result, ultrafine particles having a low refractive index may be obtained.

  The minor axis and major axis of the tin-modified rutile-type titanium oxide ultrafine particles obtained by this method have a minor axis and a major axis of 2 to 20 nm, and an average aggregated particle diameter of 10 to 100 nm.

  Although the reaction mechanism (reaction mechanism) by which the tin-modified rutile-type titanium oxide ultrafine particles of the present invention are obtained is not sufficiently clear at present, this is characterized in that the surface is modified with a tin compound. It is presumed that the tin compound used as the raw material, the tin ion dissociated in the solution, or the tin compound generated in the solution by hydrolysis or the like adhered to the titanium oxide surface by coordination, adsorption, chemical bonding, or the like. In addition, it is presumed that the tin compound was originally added as a modifier under the conditions for producing rutile type titanium oxide instead of the anatase type, and this was caused as a result of the inhibition of crystal growth in the major axis direction. This indicates that the amount of the modified tin compound necessary for obtaining tin-modified titanium oxide ultrafine particles having a crystal diameter of 2 to 20 nm is far from the amount of titanium oxide coated without a gap, and the molar ratio to titanium is 0. It can be seen from the small amount of 001-0.5.

  The reaction product obtained as described above may be used as tin-modified rutile-type titanium oxide ultrafine particles or sol liquid as it is, or may be subjected to a desired post-treatment. That is, it can be purified by a known method such as vacuum concentration using an evaporator or ultrafiltration, and concentrated to an appropriate concentration. Centrifugation can yield a white precipitate that can be redispersed in water or other desired media. The sol liquid in which tin-modified rutile-type titanium oxide ultrafine particles are dispersed in water is substituted with an organic solvent such as alcohols such as methanol and cellosolves such as 2-methoxyethanol, and organic solvent-dispersed tin-modified rutile-type titanium oxide It can also be used as an ultrafine particle sol solution.

  Next, a method for preparing the coating layer will be described.

  In the present invention, when the tin-modified rutile-type titanium oxide ultrafine particles synthesized above or a sol solution thereof is used for an optical material, a hard coat material, a resin lens, etc., in order to prevent deterioration of surrounding organic substances due to the photocatalytic property of titanium oxide, It is necessary to impart light resistance. For this purpose, tin-modified rutile titanium oxide ultrafine particles are coated with antimony oxide and silicon oxide. In addition, a coating means both the form which covered the ultrafine particle surface completely, or the form with which the clearance gap was vacant.

  The antimony oxide used for the coating is not particularly limited, and examples thereof include antimony chloride, antimony alkoxide, antimony acetate, antimony oxide, antimony potassium tartrate, potassium hexahydroxoantimonate, potassium antimonate, and sodium antimonate. I can do it. The antimony oxide here may be an amorphous oxide, a crystalline oxide, or a hydrated state. Further, it may contain a state in which antimonic acid or a salt thereof is adsorbed and bound to the surface of the nuclear fine particles.

  First, it is coated with antimony oxide. As a method for forming the coating layer, first, an aqueous sol solution of tin-modified rutile-type titanium oxide ultrafine particles is prepared. It is desirable that the concentration of this dispersion is in the range of 0.01 to 50% by weight, preferably 0.1 to 10% by weight as the solid content. If the solid content concentration of the dispersion is less than 0.01% by weight, the productivity is low and not industrially effective, and if the solid content concentration of the dispersion exceeds 50% by weight, the resulting ultrafine particles may become aggregates. There is sex.

  Next, antimony oxide is added to an aqueous sol solution of tin-modified rutile-type titanium oxide ultrafine particles. The amount of antimony oxide added is such that the proportion of antimony oxide in the finally obtained antimony oxide-coated tin-modified rutile titanium oxide ultrafine particles is in the range of 1 to 90% by weight. If it is smaller than this, the light resistance may not be sufficient. If it is larger than this, a sufficient refractive index may not be obtained.

  A solution prepared by dissolving the antimony oxide in water and / or an organic solvent is added to the water-sol solution of the tin-modified rutile-type titanium oxide ultrafine particles while appropriately adjusting the pH and temperature of the solution as necessary. The coating layer can be formed by aging according to the above. After the coating layer is formed, impurities may be removed by washing treatment by ultrafiltration or the like.

  Subsequently, it is coated with silicon oxide. Examples of the silicon oxide used for the coating include silicates such as sodium silicate and potassium silicate. A silicate sol obtained by cation exchange of silicate by a conventionally known method or addition of an acid, or a silicate sol stabilized by adding a base is preferred. The silicon oxide here may be an amorphous oxide, a crystalline oxide, or a hydrated state. Further, a state in which silicic acid, silicic acid oligomer or a salt thereof is adsorbed and bonded to the surface of the core fine particle may be used.

  As a method for forming the coating layer, first, an aqueous sol solution of antimony oxide-coated tin-modified rutile-type titanium oxide ultrafine particles is prepared. It is desirable that the concentration of this dispersion is in the range of 0.01 to 50% by weight, preferably 0.1 to 20% by weight as the solid content. If the solid content concentration of the dispersion is less than 0.01% by weight, the productivity is low and not industrially effective, and if the solid content concentration of the dispersion exceeds 50% by weight, the resulting ultrafine particles may become aggregates. There is sex.

  A solution in which silicon oxide is dissolved in water and / or an organic solvent is continuously or intermittently added to a reaction solution containing nuclear fine particles (in this case, ultrafine particles of tin-modified rutile titanium oxide coated with antimony oxide). The reaction is performed on the surface of the nuclear fine particles. It is desirable to add dropwise to such an extent that the core fine particle sol solution does not gel over 1 to 100 hours. The pH of the reaction solution is preferably maintained in the range of 7 to 11, and more preferably 8 to 10. When the pH is in this range, polymerization on the surface of the core fine particles proceeds and a dense coating layer can be obtained. If it is larger than this range, the dispersibility of the resulting fine particles may be lowered. If it is smaller than this range, the polymerization may not proceed easily.

  The concentration of silicic acid or silicate after completion of dropping in the reaction solution is preferably 0.01 to 5 wt%, more preferably 0.5 to 2 wt% in terms of silicon oxide. If it is smaller than this, silicic acid or silicate may not be polymerized and a dense coating layer may not be formed. If it is larger than this, the polymerization may proceed excessively and gelation or insoluble matter may be generated.

  The reaction temperature is usually preferably from room temperature to 200 ° C, more preferably from 80 ° C to 180 ° C. If it is lower than this, a dense coating layer may not be formed. If it is higher than this, the fine particles may be gelled.

  After forming the coating layer, it is desirable to remove impurities by washing by ultrafiltration or the like.

  The antimony oxide and silicon oxide-coated tin-modified rutile titanium oxide ultrafine particles obtained in this manner have a refractive index of antimony oxide and silicon oxide-coated tin-modified rutile titanium oxide ultrafine particles themselves depending on the amount of the coating layer. And light resistance can be adjusted. Light resistance can be imparted and the refractive index can be adjusted from 1.5 to 2.8.

  The amount of antimony oxide and silicon oxide to be used is not particularly limited, but the weight ratio of coating layer / nuclear fine particles is preferably 1/99 to 90/10. If it is smaller than this range, the photocatalytic property of titanium oxide cannot be suppressed, and the light resistance may deteriorate. If it is larger than this range, the necessary refractive index may not be obtained.

  The weight ratio between the antimony oxide and the silicon oxide contained in the coating layer is not particularly limited, but is preferably antimony oxide / silicon oxide = 100/1 to 1/50. If it is larger than this, the light resistance may deteriorate. If it is smaller than this, the dispersibility may be deteriorated, or the necessary refractive index may not be obtained.

  In the method for producing composite oxide ultrafine particles of the present invention, the coating layer is formed with antimony oxide and then coated with silicon oxide, or the coating layer is formed with silicon oxide and then coated with antimony oxide. However, when tin-modified rutile-type titanium oxide ultrafine particles are first coated with a silicon compound, dispersion stability may be deteriorated, and therefore it is desirable to perform coating with antimony oxide first. One oxide may be added to the core fine particle sol solution to coat, and after purification such as ultrafiltration, the other oxide may be coated, or it may be added as it is without purification.

  The reaction product obtained as described above may be used as it is as an antimony oxide + silicon oxide-coated tin-modified rutile-type titanium oxide ultrafine particle sol solution, or may be subjected to a desired post-treatment. That is, it can be purified by a known method such as vacuum concentration using an evaporator or ultrafiltration, and concentrated to an appropriate concentration. Centrifugation can yield a white precipitate that can be redispersed in water or other desired media. The aqueous sol solution in which antimony oxide + silicon oxide-coated tin-modified rutile-type titanium oxide ultrafine particles are dispersed is replaced with an organic solvent such as alcohols such as methanol and cellosolves such as 2-methoxyethanol. It can also be used as a sol solution of antimony oxide and silicon oxide-coated tin-modified rutile type titanium oxide ultrafine particles dispersed in the solution.

  By modifying the composite oxide ultrafine particles obtained by the present invention, that is, antimony oxide + silicon oxide coated tin-modified rutile titanium oxide ultrafine particles with carboxylic acid, amine, organic silicon oxide, or organic polymer, It can also be used as a surface-modified antimony oxide and silicon oxide-coated tin-modified rutile-type titanium oxide ultrafine particle sol solution. This improves dispersibility and compatibility with organic solvents and resins.

  As the carboxylic acid used for the surface treatment, acetic acid, propionic acid, acrylic acid, methacrylic acid, tartaric acid, glycolic acid and the like are preferably used.

  Further, as the amine used for the surface treatment, propylamine, diisopropylamine, butylamine and the like are preferably used. In order to perform surface treatment with these, for example, ultrafine particles or a sol solution is mixed in a solution such as water or alcohol, and after adding a catalyst as necessary, it is left at room temperature for a predetermined time or is subjected to heat treatment. Good.

  For the organosilicon oxide surface treatment, tetramethoxysilane, methyltrimethoxysilane, (3-glycidoxypropyl) trimethoxysilane, or the like is preferably used. As a treatment method, a sol solution is mixed with a solvent containing an organosilicon oxide, a catalyst is added if necessary, and the mixture is heated for a predetermined time in a range of room temperature to 60 ° C. and then subjected to ultrafiltration, centrifugation, or the like. It is performed by a method such as removing unreacted components in the mixed solution.

  The organic polymer is preferably a polymer having a functional group capable of interacting with the surface of the fine particles such as amino group and carboxylic acid group, such as reaction and adsorption. Polystyrene aminated, chloromethylated, sulfonated, and their derivatives, styrene resins, polymethyl methacrylate, polyethyl acrylate, polyacrylic acid, polyacrylamide and other acrylic resins, vinyl alcohol resins, epoxy Based resins and the like. The surface treatment method may be performed by the method described above.

  The amount of the surface treatment agent to be used is appropriately set in consideration of dispersibility in a binder such as an organic solvent and a resin to be used.

  By this method, ultrafine particles of antimony oxide + silicon oxide-coated tin-modified rutile type titanium oxide having a minor axis and a major axis of 2 to 20 nm and an average aggregated particle diameter of 10 to 100 nm are obtained.

  When the crystal diameter is smaller than 2 nm, there is a possibility that the refractive index originally obtained when used for optical materials, hard coat materials, resin lenses and the like containing these may not be obtained. In addition, when a hard coat film or the like is prepared using a coating solution, scratch resistance and hardness may be insufficient. If it is larger than 20 nm, light scattering may occur. If the average aggregate particle size is larger than 100 nm, the resulting coating film may become cloudy and opaque.

  EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these Examples.

(Preparation of tin-modified rutile-type titanium oxide ultrafine particle sol solution and antimony oxide + silicon oxide-coated tin-modified rutile-type titanium oxide ultrafine particle sol solution)
Preparation)

(Tin-modified rutile titanium oxide ultrafine particle sol solution)
Tin tetrachloride pentahydrate 0.27 g was charged into a 100 ml eggplant type flask, dissolved in 50 ml of ion-exchanged water, and 5 ml of a hydrochloric acid aqueous solution of titanium oxide chloride (containing 15 wt% Ti) was added. The pH of the solution was -0.1. (Ti concentration of Ti = 0.45, Sn / Ti = 0.03) The mixture was stirred with a magnetic stirrer and heated at 50 ° C. for 1 hour to obtain a white precipitate. Centrifugation was performed, and the white precipitate was collected and redispersed in ion-exchanged water. Ultrafiltration was performed to obtain a sol solution having a solid content of 2% by weight. This solid was subjected to powder X-ray diffraction measurement and electron microscope observation. When hot-air drying was performed at 120 ° C. for 2 hours and powder X-ray diffraction measurement was performed, it was a titanium oxide rutile type. The crystal diameter was calculated from the half-value width of the diffraction peak using the Debye-Scherrer equation. As a result, the average crystal diameter was 5 nm for the minor axis and 8 nm for the major axis, respectively. The observation with an electron microscope was performed using a transmission electron microscope, and a solution obtained by dropping a diluted sol solution onto a mesh was observed at a magnification of 200,000 times and 2 million times. As a result, it was a rutile type titanium oxide having an average aggregated particle size of 23 nm. The elemental molar ratio of Sn / Ti by inductively coupled plasma analysis was 0.02.

(Antimony oxide + silicon oxide coated tin modified rutile titanium oxide ultrafine particle sol solution)
After adding 20 g of potassium hydroxide to 240 g of an aqueous suspension of 30 g of antimony trioxide and heating to 70 ° C., 30 g of 35 wt% aqueous hydrogen peroxide was added dropwise to give a 10 wt% antimonate aqueous solution in terms of antimony pentoxide. Prepared. The pH was 8.3.

  Ion exchange water was added to water glass (containing 35% by weight of silicon oxide) to give a 3% by weight aqueous solution in terms of silicon oxide.

  The aqueous solution was passed through a cation exchange resin to prepare a silicate sol solution having a pH of 2.6. Subsequently, a 10 wt% aqueous sodium hydroxide solution was added dropwise until pH = 8.2 to obtain a 2 wt% stabilized silicate sol solution.

  66 g of the above antimonate aqueous solution was added to 1500 g of a 2 wt% tin-modified rutile-type titanium oxide ultrafine particle sol solution and heated at 85 ° C. for 8 hours. The solution was purified by ultrafiltration to obtain a 4 wt% antimony oxide-coated tin-modified rutile-type titanium oxide ultrafine particle sol solution.

  2500 g of this antimony oxide-coated tin-modified rutile titanium oxide ultrafine particle sol solution was heated to 90 ° C. While removing the water under reduced pressure and keeping the liquid volume at 2500 g, 630 g of the above-mentioned stabilized silicate sol solution was added dropwise over 90 hours and further heated for 3 hours. Purification was performed by ultrafiltration to prepare a 10 wt% antimony oxide + silicon oxide-coated tin-modified rutile type titanium oxide ultrafine particle sol solution. After elemental analysis by inductively coupled plasma method after drying with hot air at 120 ° C. for 2 hours, the weight ratio of antimony oxide / silicon oxide / tin modified titanium oxide in terms of oxide = 0.12 / 0.9 / 1. there were. The light resistance evaluation test and the refractive index were evaluated as follows.

(A) Light resistance test Sodium alizarin red sulfonate (hereinafter referred to as AR) was used as a dye. A sol solution ultrafiltered in a 1 cm side quartz cell was taken out in an amount equivalent to 6 mg of solid content, and 3 g of an AR aqueous solution of 2 × 10 ⁻⁴ mol / l was added and stirred. After mixing, the mixture was stirred in the dark and irradiated with a xenon lamp, assuming that the adsorption equilibrium was reached when the absorption peak ceased to change. Cut infrared light by using of H _{2 O} filter illumination light outlet. A cell was placed at a position 10 cm from the outlet and stirred. The illuminance at this position was 120 to 130 mW / cm ² and about 2.5 times that of normal sunlight. Absorption spectrum is measured every 10 minutes, the horizontal axis is time, and the vertical axis is the dye residual ratio (A / A ₀ ) (ratio of absorbance (A) at each time to maximum absorbance (A ₀ ) before irradiation). Were prepared and compared with each sol solution. The absorption spectrum was measured using a spectrophotometer UV-2200 (manufactured by Shimadzu Corporation). The result is shown in FIG.

(B) Measurement of coating film refractive index A solution obtained by adding polyvinylpyrrolidone to each sol solution so that the weight ratio to the fine particles was 1 was spin-coated, dried at 120 ° C., and then immediately measured with an ellipsometer. . The refractive index of the solid content was evaluated from the volume fraction of the contained solid content. The results are shown in Table 1.

(Tin-modified rutile titanium oxide ultrafine particle sol solution)
The same operation as in Example 1 was carried out except that 0.9 g of tin tetrachloride pentahydrate was used in Example 1. (Feed Ti concentration = 0.45, Sn / Ti = 0.1) When the solid content of the obtained sol solution was analyzed in the same manner as in Example 1, the average crystal diameter was 5 nm for the minor axis and 8 nm for the major axis, respectively. It was a titanium oxide rutile type with an average aggregated particle size of 20 nm. The element molar ratio of Sn / Ti was 0.06.

(Antimony oxide + silicon oxide coated tin modified rutile titanium oxide ultrafine particle sol solution)
The same procedure as in Example 1 was performed except that the tin-modified rutile type titanium oxide ultrafine particle sol solution prepared above was used. The weight ratio of antimony oxide / silicon oxide / tin-modified titanium oxide in terms of oxide was 0.12 / 0.9 / 1.

  In addition, FIG. 1 and Table 1 show the light resistance evaluation test and the refractive index evaluation performed in the same manner as in Example 1.

(Tin-modified rutile titanium oxide ultrafine particle sol solution)
[Comparative Example 1]
Using the tin-modified rutile-type titanium oxide ultrafine particle sol solution prepared in Example 2, a light resistance evaluation test was performed. The results are shown in FIG.

(Zirconium oxide-coated tin-modified rutile titanium oxide ultrafine particle sol solution)
[Comparative Example 2]
After ion-exchanged water was added to 37.5 g of the tin-modified rutile-type titanium oxide ultrafine particle sol solution 47.5% by weight prepared in Example 2 to give a 1% by weight sol solution, concentrated hydrochloric acid was added to obtain pH = 0.9. Then, 4 g of zirconium oxide chloride octahydrate was added and heated at 90 ° C. for 8 hours. Ultrafiltration was performed to obtain a sol solution. The composition of the zirconium oxide-coated anatase-type titanium oxide ultrafine particles was zirconium oxide / titanium oxide weight ratio = 0.9 / 1 in terms of oxide. The light resistance evaluation test and the evaluation of the refractive index are shown in FIG.

(Zirconium oxide-coated anatase-type titanium oxide ultrafine particle sol solution)
[Comparative Example 3]
To 2 L of ion-exchanged water, 20 ml of a hydrochloric acid aqueous solution of titanium oxide chloride (Ti content 15% by weight) was added and heated at 60 ° C. for 6 hours. 50 g of an aqueous solution in which 32 g of zirconium oxide octahydrate was dissolved was dropped, heated to 90 ° C., and heated for 1 hour. After cooling to room temperature, ultrafiltration was performed. After cooling to room temperature, it was concentrated and deionized by ultrafiltration to give a 4 wt% sol solution. The composition of the zirconium oxide-coated anatase-type titanium oxide ultrafine particles was zirconium oxide / titanium oxide weight ratio = 0.85 / 1 in terms of oxide. The light resistance evaluation test and the evaluation of the refractive index are shown in FIG.

  As can be seen from the above results, high refractive index and fine particle photocatalytic properties that cannot be obtained by using anatase type titanium oxide by coating rutile type titanium oxide ultrafine particles with antimony oxide + silicon oxide effectively It can be seen that suppressed composite oxide ultrafine particles are obtained.

  The composite oxide ultrafine particles of the present invention, that is, the composite oxide-coated tin-modified rutile-type titanium oxide ultrafine particles, cannot be achieved by the conventional production method, and the high refractive index ultrafine particles cannot be obtained by the anatase type. A sol solution can be provided. The composite oxide ultrafine particles of the present invention have high refractive index and ultraviolet shielding properties as rutile titanium oxide by coating tin-modified rutile titanium oxide ultrafine particles with antimony oxide and silicon oxide. The photocatalytic property is effectively suppressed. By using the resulting composite oxide ultrafine particles and sol solution, an antireflection film excellent in scratch resistance, surface hardness, abrasion resistance, transparency, heat resistance, weather resistance, ultraviolet shielding properties, etc., Plastic deterioration prevention additive, cosmetic additive, eyeglass lens, camera lens, automotive window glass, plasma display, liquid crystal display, EL display, optical filter and other optical members, metal material, ceramic material, glass material, plastic material It can be suitably used for products such as surface treatment agents such as dielectric materials, electronic materials such as piezoelectric materials, and water repellents.

The result of the light resistance evaluation test of an Example and a comparative example is shown.

Claims (5)

  In the presence of a tin compound having a molar ratio of tin to titanium (Sn / Ti) of 0.001 to 2, a titanium compound aqueous solution having a Ti concentration of 0.07 to 5 mol / l is reacted in a pH range of −1 to 3. The obtained Sn / Ti composition molar ratio is 0.001 to 0.5, and the rutile-type titanium oxide ultrafine particles having a minor axis of crystal diameter and a major axis of 2 to 20 nm are used as core fine particles, and the antimony oxide. A composite oxide ultrafine particle comprising a coating layer containing a silicon oxide and a minor axis of crystal diameter and a major axis of 2 to 20 nm.   The weight ratio of coating layer / nuclear fine particles is 1/99 to 90/10, and the weight ratio of antimony oxide / silicon oxide contained in the coating layer is 100/1 to 1/50. The ultrafine composite oxide according to claim 1.   The composite oxide ultrafine particles according to claim 1 or 2, having a refractive index of 1.5 to 2.8.   A composite oxide ultrafine particle, wherein an average aggregate particle diameter of the crystal of the ultrafine particle aggregate comprising the composite oxide ultrafine particle according to any one of claims 1 to 3 is 10 to 100 nm.   A sol obtained by dispersing the composite oxide ultrafine particles according to claim 1 in water or an organic solvent.

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