JPWO2007052580A1 - Resin composition containing ultrafine oxide particles - Google Patents

Abstract

From inorganic oxide ultrafine particles containing titanium oxide having a rutile-type crystal structure with a refractive index of 1.5 to 2.8, or a coating layer containing one or more inorganic oxides using the ultrafine particles as core fine particles It is a resin composition containing the composite inorganic oxide ultrafine particles, and an optical member formed using the resin composition.

Description

  The present invention relates to a resin composition containing inorganic oxide ultrafine particles or composite inorganic oxide ultrafine particles.

  Inorganic glass is excellent in various physical properties such as excellent transparency, and is used in a wide field as an optical member. However, it is disadvantageous in that it is heavy and easily damaged, and the workability and productivity are poor. Thus, transparent optical resins have been actively developed as a material to replace inorganic glass. Non-represented by acrylic resin, styrene resin, polycarbonate resin, polyester resin, olefin resin, alicyclic acrylic resin, alicyclic olefin resin, polyurethane resin, polyether resin, polyamide resin, polyimide resin A curable resin such as a crystalline thermoplastic resin, an epoxy resin, or an unsaturated polyester resin has good transparency in the visible region wavelength, and more moldability, mass productivity, or flexibility than an inorganic glass material. It is a general-purpose transparent resin material having excellent characteristics such as toughness and impact resistance. By providing such a transparent resin material with a high refractive index, a thin and light optical lens (glass lens, pickup lens in information recording equipment such as CD, DVD, lens for photographing equipment such as digital camera, etc.), optical prism Development to high refractive optical member materials such as optical waveguides, optical fibers, thin film moldings, optical adhesives, and optical semiconductor sealing materials is expected.

  For example, in the field of spectacle lenses, in order to meet the needs of fashionableness, it is necessary to reduce the center thickness, edge thickness, and curvature of the lens, and to be thin overall. In this respect, a higher refractive index is required. In recent years, research into increasing the refractive index by using a monomer containing an element having a large atomic number such as sulfur or a halogen element has been actively conducted. For example, there is a resin obtained by thermally polymerizing a thiol compound and an isocyanate compound to form a thiourethane bond (nd = 1.60 to 1.67) (Japanese Patent Laid-Open No. 9-110956). However, since it is a special high refractive index resin using a non-general special monomer, there is a problem that the industrial application field is extremely limited. Although it is increased by the introduction of such a halogen element or sulfur element, the refractive index of the organic resin is determined by the element used and the molecular structure, and is usually limited to a range of about 1.4 to 1.7. Therefore, amorphous resin represented by acrylic resin, styrene resin, polycarbonate resin, polyester resin, olefin resin, alicyclic acrylic resin, alicyclic olefin resin, polyurethane resin, polyether resin, polyamide resin, polyimide resin. High refractive index technology using a general-purpose transparent resin such as a curable thermoplastic resin, or a curable resin such as an epoxy resin or an unsaturated polyester resin, particularly a high refractive index resin having a refractive index of 1.7 or more is strongly demanded. ing.

  Also, for example, for a polymer optical fiber using an acrylic resin such as polymethyl methacrylate (PMMA), the refractive index of the core part (center part in the optical fiber cross section) is higher than that of the cladding part (same outer peripheral part). As the rate difference is larger, the numerical aperture corresponding to the maximum angle at which light can propagate can be increased.

  For example, in a light emitting diode, a light emitting element portion is sealed with an epoxy resin or the like. In general, the refractive index of a semiconductor constituting the semiconductor element portion is very high. If the refractive index of a substance in contact with the semiconductor element portion is low, the critical angle is small and total reflection tends to occur. Therefore, the angle at which the total reflection occurs can be increased by sandwiching the light emitting element with a material having a higher refractive index, and the light beam extraction efficiency is improved accordingly.

  Furthermore, there is a demand for the development of a material that uses a plurality of materials having different refractive indexes, such as an optical fiber, an optical waveguide, and some lenses, or has a distribution in the refractive index. In order to cope with these materials, it is indispensable to arbitrarily adjust the refractive index.

  General-purpose resins used for optical members, such as acrylic resins, styrene resins, polycarbonate resins, polyester resins, olefin resins, alicyclic acrylic resins, alicyclic olefin resins, polyurethane resins, polyether resins, polyamides It is strongly desired to increase the refractive index of a thermoplastic resin typified by a resin, a polyimide resin or the like, or a curable resin such as an epoxy resin or an unsaturated polyester resin.

  In recent years, for the purpose of increasing the refractive index of resins, transparent inorganic oxide fine particles having a high refractive index having a crystal structure such as Zr, Sn, Sb, Mo, In, Zn, Ti, or composite oxides thereof have been dispersed. A technique for forming a colorless and transparent high refractive index resin by introducing it into the resin while maintaining the state has been proposed. Since high dispersibility and transparency are required for use in such applications, the metal oxide is preferably ultrafine particles.

  However, in the above technique, it has not been sufficient to design a resin having a high refractive index while using a matrix amount that can maintain strength and the like. This is because if the content of fine particles is too large to increase the refractive index, the resin becomes brittle.

  Therefore, a method using titanium oxide fine particles has been proposed. Since titanium oxide has a particularly high refractive index and high transparency, the resin can have a high refractive index in a smaller amount than other fine particles. Titanium oxide includes a rutile type and an anatase type as typical crystal types. So far, materials mainly composed of anatase-type titanium oxide ultrafine particles having a refractive index no = 2.56 and ne = 2.49 have been mainly used as high refractive index metal oxide ultrafine particle sol solutions. Yes. On the other hand, the refractive index of rutile-type titanium oxide has a refractive index no = 2.61, ne = 2.9 (no: refractive index for ordinary light, ne: refractive index for extraordinary light) (Chemical Society of Japan, Experimental Science) It is known that the optical properties such as high refractive index and ultraviolet absorption are superior to those of anatase type, and attempts to synthesize the rutile titanium oxide ultrafine particles and sol liquid are positive. It was done. 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), an aggregate having an aggregate particle diameter of 200 to 400 nm formed by gathering long fibrous rutile type titanium oxide is produced. Then, it was impossible to use industrially.

  On the other hand, a resin composed of an organic matrix and titanium oxide fine particles has a drawback that its light resistance is lowered. That is, due to the photocatalytic action of titanium oxide, organic matter decomposition due to electron-holes generated by light absorption occurs, and transparency, light resistance, weather resistance, heat resistance, ultraviolet shielding properties, and the like are serious problems.

  At present, for the purpose of improving the light resistance of a resin composition containing such anatase-type titanium oxide ultrafine particles, for example, ultrafine particles combining anatase-type titanium oxide and an inorganic oxide as described in Patent Document 1, or anatase Ultrafine particles obtained by coating type titanium oxide with an inorganic oxide and sol liquids thereof are applied.

All of these are aimed at inactivating the anatase-type titanium oxide ultrafine particles by coating with an inorganic oxide. Thus, light resistance is improved by coat | covering a titanium oxide ultrafine particle with an inorganic oxide. However, since the titanium oxide used is anatase type, the refractive index is about 2.5, and when coated with an oxide to improve light resistance, the refractive index is greatly reduced, The refractive index is lower than that of the original anatase titanium oxide, and the effect of improving the refractive index of optical materials, hard coat materials, resin lenses, etc. is low. Further, even if the amount of the metal oxide to be coated is reduced and the refractive index is increased, the light resistance is insufficient, and the transparency, heat resistance, ultraviolet shielding property, etc. of the resin composition are problematic.
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.

Similarly, ultrafine particles with a high refractive index and sol solution excellent in transparency, dispersibility, light resistance, weather resistance, etc., and sol liquid are optical lenses (photographing lenses such as eyeglass lenses, CDs, DVDs, pickup lenses, digital cameras, etc.) Lenses for equipment, etc.), optical prisms, optical waveguides, optical fibers, thin film molded products, optical adhesives, materials for high refractive optical members such as sealing materials for optical semiconductors, etc., as well as plastic deterioration prevention additives, cosmetic additives There is also a demand in the product fields such as automotive window glass, plasma displays, liquid crystal displays, EL displays, optical members such as optical filters, metal materials, ceramic materials, glass materials, plastic materials, photocatalysts and the like.
JP 2001-123115 A

  The object of the present invention has been achieved in view of the above-described circumstances, and has a high refractive index and excellent transparency, dispersibility, light resistance, weather resistance, etc., and inorganic oxide ultrafine particles and high refractive index in which the ultrafine particles are dispersed. It is in providing a rate resin composition and an optical material. In particular, thin and light optical lenses (glass lenses, pickup lenses in information recording devices such as CDs and DVDs, lenses for photographing devices such as digital cameras), optical prisms, optical waveguides, optical fibers, thin film moldings, optical adhesives An object of the present invention is to provide a material for an optical member such as an optical semiconductor sealing material.

The present invention
(1) Inorganic oxide ultrafine particles having a refractive index of 1.5 to 2.8 containing titanium oxide having a rutile-type crystal structure, or comprising the ultrafine particles as core fine particles and containing one or more inorganic oxides A composite inorganic oxide ultrafine particle having a refractive index of 1.5 to 2.8 composed of a coating layer;
A resin composition comprising:
(2) The resin composition according to (1), wherein the rutile-type titanium oxide is titanium oxide having a tin-modified rutile-type crystal structure.
(3) The resin composition according to (2), wherein the ultrafine particles have a Sn / Ti composition molar ratio of 0.001 or more and 0.5 or less.
(4) The rutile titanium oxide ultrafine particles in the inorganic oxide ultrafine particles containing titanium oxide having the rutile crystal structure have a molar ratio of tin to titanium (Sn / Ti) of 0.001 to 2. It is obtained by reacting a titanium compound aqueous solution having a Ti concentration of 0.07 to 5 mol / l in the range of pH -1 to 3 in the presence of a tin compound, and the Sn / Ti composition molar ratio is 0.001 to 0.5. The resin composition according to (1), which is a tin-modified rutile-type titanium oxide ultrafine particle.
(5) The content of titanium oxide having a rutile-type crystal structure contained in the inorganic oxide ultrafine particles is 5 to 100% by weight based on the weight of the inorganic oxide ultrafine particles. (1) -Resin composition in any one of (4).
(6) Based on the total weight of the resin composition, the content of the inorganic oxide ultrafine particles or the composite inorganic oxide ultrafine particles is 0.1 to 90% by weight of (1) to (5) The resin composition in any one.
(7) The resin composition according to any one of (1) to (6), wherein a weight ratio of the coating layer / nuclear particles of the composite inorganic oxide ultrafine particles is 1/99 to 90/10.
(8) The resin composition according to any one of (1) to (7), wherein a minor axis and a major axis of the crystal diameter of the inorganic oxide ultrafine particles or the composite inorganic oxide ultrafine particles are 2 to 20 nm.
(9) The resin composition according to any one of (1) to (8), wherein an average aggregate particle diameter of an aggregate composed of the inorganic oxide ultrafine particles or the composite inorganic oxide ultrafine particles is 10 to 100 nm.
(10) The resin composition according to any one of (1) to (9), wherein the inorganic oxide ultrafine particles or the composite inorganic oxide ultrafine particles is a sol formed by dispersing in water or an organic solvent.
(11) The resin composition according to any one of (1) to (10), which has a refractive index of 1.5 to 2.8.
(12) An optical member comprising the resin composition according to any one of (1) to (11).
(13) The optical member according to (12), characterized by being used for an optical lens, an optical prism, an optical waveguide, an optical fiber, a thin film molding, an optical adhesive, or an optical semiconductor sealing material,
It is about.
Furthermore, the present invention includes the following configurations.
(A) In the coexistence 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 in a pH range of −1 to 3. And reacting to obtain inorganic oxide ultrafine particles containing titanium oxide having a rutile-type crystal structure, and the Sn / Ti composition molar ratio of the inorganic oxide ultrafine particles is 0.001 to 0.5. And a method for producing a resin composition containing tin-modified rutile-type titanium oxide ultrafine particles.

  The rutile-type titanium oxide ultrafine particles of the present invention can be provided by ultrafine particles having a high refractive index that cannot be obtained by the conventional production method and cannot be obtained by the anatase type. Furthermore, by coating the rutile titanium oxide ultrafine particles with an inorganic oxide, it is possible to provide composite inorganic oxide ultrafine particles with a high refractive index that are excellent in transparency, dispersibility, light resistance, weather resistance and the like. Provided a high refractive index resin composition excellent in transparency, light resistance, weather resistance, heat resistance, molding processability, and the like and an optical member using the same when the obtained ultrafine particles are applied to an optical material. It became possible to do.

  ADVANTAGE OF THE INVENTION According to this invention, it has the outstanding transparency and high refractive index, and can provide the novel resin composition used as an optical member. Specifically, it is composed of a high refractive index rutile-type titanium oxide ultrafine particle excellent in transparency, dispersibility, light resistance, weather resistance, etc., or a coating layer containing the ultrafine particle as a core fine particle and containing one or more inorganic oxides. It is possible to provide a resin composition in which ultrafine particles of composite inorganic oxide are dispersed in an organic medium such as a transparent resin at a high concentration.

  Since the resin composition of the present invention has characteristics such as a high refractive index and a high light transmittance due to the presence of the rutile-type titanium oxide ultrafine particles, it is used in an information recording device such as an optical lens (glasses lens, CD, DVD). It can be used as a material for high refractive index optical members such as pickup lenses, lenses for digital cameras and other imaging devices), optical prisms, optical waveguides, optical fibers, thin film moldings, optical adhesives, sealing materials for optical semiconductors, etc. .

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

The present invention relates to inorganic oxide ultrafine particles containing titanium oxide having a rutile crystal structure with a refractive index of 1.5 to 2.8, or the ultrafine particles as core fine particles, and one or more inorganic oxides are used. A resin composition comprising composite inorganic oxide ultrafine particles composed of a coating layer.
As described above, since the rutile type has a higher refractive index than the anatase type, it is possible to achieve a higher refractive index by using ultrafine particles of rutile type titanium oxide. Furthermore, in order not to impair the transparency of the resin, the rutile titanium oxide needs to be ultrafine particles.

  In the present invention, the inorganic oxide ultrafine particles containing titanium oxide having a rutile-type crystal structure is not particularly limited as long as it contains the ultrafine particles of rutile-type titanium oxide as described above. Usually, in the inorganic oxide ultrafine particles, the ratio of rutile-type titanium oxide is 5 to 100% (weight ratio), preferably 50 to 100%, and more preferably 70 to 100%.

  Further, the components other than the ultrafinely divided rutile type titanium oxide are not particularly limited as long as they do not impair the transparency of the resin of the present invention. Among them, inorganic oxides are desirable. Specific examples include oxides such as Al, Si, V, Fe, Zn, Zr, Nb, Mo, Sn, Sb, and W, and preferably oxidation of Al, Si, Zr, Sn, and Sb. It is a thing.

  In addition, the present inventors have found that a tin compound used as a sintering agent prevents long fiber formation and aggregation, and a tin-modified rutile titanium oxide ultrafine particle, a sol solution excellent in transparency, dispersibility, etc. It was found that it can be obtained. Furthermore, by forming this as a core ultrafine particle and coating with an inorganic oxide, a composite inorganic oxide ultrafine particle having an average particle diameter of 1 to 100 nm having a high refractive index excellent in transparency, dispersibility, light resistance, weather resistance, etc., It has been found that a sol solution having excellent dispersibility can be obtained. And, by dispersing the ultrafine particles in the resin matrix at a high concentration, high refractive index, transparency, light resistance, weather resistance, heat resistance, molding, which could not be obtained when using conventional anatase type titanium oxide Optical materials such as resin compositions having excellent processability and optical lenses (glass lenses, pickup lenses, etc.), optical prisms, optical waveguides, optical fibers, thin-film molded products, optical adhesives, and optical semiconductor sealing materials It was found that it can be obtained.

  In the present invention, a preferable rutile-type titanium oxide ultrafine particle has 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 titanium compound solution in a pH range of −1 to 3, and the Sn / Ti composition molar ratio of the ultrafine particles is 0.001 to 0.5. The ultrafine particles are characterized in that the minor axis and the major axis of the crystal diameter are 2 to 20 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.
The crystal diameter and average aggregated particle diameter of the prepared ultrafine particles are a transmission electron microscope of a sample in which the prepared ultrafine particle sol solution is dropped on an electron microscope observation mesh, or a sample in which a section of ultrafine particle-containing dispersion resin is cut out with a microtome. It can be evaluated by observation.

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. Moreover, the transparency of the resin composition 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 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 composite inorganic oxide ultrafine particles, that is, inorganic oxide-coated tin-modified rutile titanium oxide ultrafine particles will be described.

  In the present invention, when tin-modified rutile type titanium oxide fine particles synthesized as described above or a sol solution thereof is used for a resin composition, it is necessary to impart light resistance in order to prevent deterioration of surrounding organic substances due to the photocatalytic property of titanium oxide. become. For this purpose, tin-modified rutile titanium oxide fine particles are coated with an inorganic oxide. In addition, a coating means both the form which covered the fine particle surface completely, or the form with which the clearance gap was opened.

  Examples of inorganic oxides used for the coating include Zr, Si, Al, Sb, Sn, Mo, Nb, Zn, Ta, Fe, W, Bi, Ce, Pb, Cu, Y, In, V, Mg, La, and the like. The oxide is preferred. These can be used by coating only one kind, or two or more kinds can be used for coating. The inorganic oxide may be individually coated, combined and coated, solid solution coated, or coated with one kind and then coated with another. Further, it may be an amorphous oxide, a crystalline oxide, or a hydrated state. Further, it may be in an adsorbed and bound state on the surface of the core fine particles in the form of acids such as silicic acid and antimonic acid, oligomers thereof or salts thereof.

  The inorganic oxide-coated tin-modified rutile-type titanium oxide ultrafine particles obtained in this way can adjust the refractive index and light resistance of the ultrafine particles themselves depending on the inorganic oxide species and the amount selected for the coating layer. Light resistance can be imparted and the refractive index can be adjusted to 1.5 to 2.8, and further, it can be adjusted in the range of 2.0 to 2.8.

  The coating amount of the inorganic 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 coating method of the inorganic oxide can be performed by applying a known method to a sol solution of tin-modified rutile titanium oxide ultrafine particles. That is, a compound as a raw material is dissolved in water, mixed with a tin-modified rutile-type titanium oxide ultrafine particle sol solution, and stirred. You may heat as needed. Moreover, you may adjust pH as needed.

  For example, when performing silicon oxide coating, examples of the raw material compound used include sodium silicate and potassium silicate.

  For example, when aluminum oxide coating is performed, examples of the raw material compound used include sodium aluminate, aluminum sulfate, and aluminum chloride.

  In addition, for example, when antimony oxide coating is performed, as raw material compounds used, antimony chloride, antimony alkoxide, antimony acetate, antimony oxide, potassium antimony tartrate, potassium hexahydroxoantimonate, potassium antimonate, sodium antimonate, etc. Can be mentioned.

  Further, for example, when coating with zirconium oxide, it can be carried out according to the method described in JP-A No. 2004-18311 found by the present inventors. Examples of the raw material compound used include zirconium oxychloride, zirconium oxysulfate, zirconium oxynitrate, and zirconium oxycarbonate.

  For example, in the case of coating with molybdenum oxide, hexamolybdate hexaammonium tetrahydrate, molybdenum oxide, and the like can be given.

  For example, in the case of coating with niobium oxide, niobium ethoxide, sodium niobate and the like can be mentioned.

  In the present invention, the dispersibility of the inorganic oxide-coated tin-modified rutile-type titanium oxide ultrafine particles can be changed by utilizing the difference in isoelectric point of the inorganic oxide used for coating. For example, when Si, Nb, W, Mo, Sb or the like is used, a sol solution having excellent dispersibility can be obtained particularly under basic conditions. For example, when Zr, Bi or the like is used, a sol having excellent dispersibility can be obtained particularly under acidic conditions.

  In the present invention, it is possible to further improve light resistance and weather resistance by coating with a plurality of inorganic oxides used for coating. Specific examples include tin-modified rutile titanium oxide ultrafine particles coated with antimony oxide and silicon oxide. These can be appropriately selected in consideration of the function to be imparted to the optical member.

  The reaction product obtained as described above may be used as it is as an inorganic 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. Inorganic sol-coated tin-modified rutile-type titanium oxide ultrafine particles dispersed in water sol are replaced with organic solvents such as alcohols such as methanol and cellosolves such as 2-methoxyethanol, and tin dispersed in the organic solvent is dispersed. It can also be used as a modified rutile type titanium oxide ultrafine particle sol solution or an inorganic oxide-coated tin modified rutile type titanium oxide ultrafine particle sol solution.

  In addition, the compatibility between the resin and the fine particles is insufficient, and if ultrafine particles are added at a high concentration, the fine particles aggregate to form large particles, which may cause the transparency of the resin composition to be lost. Tin-modified rutile-type titanium oxide ultrafine particles or inorganic oxide-coated tin-modified rutile-type titanium oxide obtained by the present invention by the methods described in JP-A-2003-037558 and JP-A-2002-047425 By modifying the surface of the ultrafine particles with carboxylic acid, amine, organosilicon oxide, organic polymer, or monomer thereof, the dispersibility and compatibility in the organic solvent, resin, or monomer thereof are improved.

  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.

  The minor axis and major axis of the tin-modified rutile-type titanium oxide ultrafine particles or inorganic oxide-coated tin-modified rutile-type titanium oxide ultrafine particles obtained according to the present invention are 1 to 100 nm, further 2 to 20 nm, average agglomeration The particle diameter is preferably 10 to 100 nm. If the crystal diameter is smaller than 2 nm, the originally obtained refractive index may not be obtained. If it is larger than 20 nm, light scattering may occur. If the average aggregate particle size is larger than 100 nm, the resulting resin composition may become cloudy and opaque.

  Next, the resin used in the present invention will be described. Optical resin is required to have characteristics such as colorless and transparent, low birefringence, low hygroscopicity, no hygroscopic deformation, high heat resistance in the manufacturing process and usage environment, and excellent moldability. Any conventional optical lens (glasses lens, pickup lens, etc.), optical prism, optical waveguide, optical fiber, thin film molding, optical adhesive, optical semiconductor sealing material, etc. It may be used as a material for the high refractive index optical member. For example, amorphous resin represented by acrylic resin, styrene resin, polycarbonate resin, polyester resin, olefin resin, alicyclic acrylic resin, alicyclic olefin resin, polyurethane resin, polyether resin, polyamide resin, polyimide resin A curable thermoplastic resin or a curable resin such as an epoxy resin or an unsaturated polyester resin is preferable.

  Specifically, acrylic resin such as methyl methacrylate (PMMA), styrene resin as polystyrene (PS), styrene and acrylonitrile copolymer (SAN), styrene and methyl methacrylate copolymer, polyester resin, etc. Examples thereof include polyethylene terephthalate and polyethylene naphthalate, and examples of the olefin resin include polymethylpentene (TPX).

  Polycarbonate resin is a polymer produced by the reaction of bisphenols and carbonates such as phosgene. The alicyclic acrylic resin is an acrylic resin in which an aliphatic cyclic hydrocarbon such as tricyclodecane is introduced into an ester substituent, and examples thereof include polycyclomethacrylate tricyclodecane and polymethacrylate norbornane. It has excellent low birefringence, low hygroscopicity, and heat resistance, and is used for pickup lenses, imaging lenses, and the like. An alicyclic olefin resin is a product in which a sterically rigid alicyclic group is introduced into the main chain of an olefin polymer, has excellent heat resistance and low hygroscopicity, and is used for lenses such as in-vehicle CD players. It has been.

  A polyether resin, a polyamide resin, a polyimide resin, or the like, which is a polymer in which a benzene ring, an aliphatic ring, or the like is connected through an ether bond, can also be used. Moreover, it is also possible to use resins in which sulfur atoms are introduced, such as thiourethane resins used for spectacle lens applications.

  In addition, a thermosetting epoxy resin is suitably used for semiconductor sealant applications.

  The method for producing the resin composition in the present invention is not particularly limited, and any method known in the art may be used as long as it is a method used to uniformly mix the fine particles and the resin.

Specifically, for example, the resin component and the ultrafine particle sol solution or the ultrafine particle powder are prepared independently, and then both are mixed or kneaded. Any method can be employed, such as a method for producing ultrafine particles under the condition that a previously produced resin is present.
In addition, ultrafine particles treated with a silane coupling agent such as trimethoxypropylmethyl acrylate are dissolved and dispersed in an acrylate monomer, which is injected and molded into a desired mold, and an optical member such as a high refractive index lens is formed by ultraviolet curing. A method of creating can also be adopted.

  From the viewpoint of dispersion stability of ultrafine particles, a method of obtaining a resin composition by uniformly mixing an ultrafine particle sol solution and a resin-dissolved solution and removing the solvent, or dispersing ultrafine particles in a resin monomer Preferred examples include a method of preparing a resin composition directly by polymerization.

  When the resin composition of the present invention is thermoplastic, conventionally known molding processes such as extrusion molding, injection molding, vacuum molding, blow molding, compression molding and the like are possible, and various molded products such as disks and films are obtained. I can do it.

  There is no restriction | limiting in particular in the quantity of the said resin matrix component used in this invention, Although it sets suitably according to a use, Ultrafine particle content contained in a resin composition is 0.1 to 90 weight% Is preferred. More preferably, it is 10 to 70% by weight. If it is smaller than this, there is a possibility that the characteristics of the fine particles such as an increase in refractive index are not imparted. When larger than this, flexibility, toughness, etc. may be insufficient.

  The ultrafine particles and sol liquid used in the present invention are preferably only tin-modified rutile titanium oxide ultrafine particles or ultrafine particles obtained by coating the ultrafine particles with an inorganic oxide. It can also be used in combination with other inorganic oxide ultrafine particles that are inferior in the effect of improving the rate. Examples thereof include colloidal silica and antimony oxide colloid.

  In addition, the resin composition of the present invention requires an ultraviolet absorber, an antioxidant, a heat stabilizer, a light stabilizer, an antistatic agent, a release agent, a plasticizer, a disperse dye, a pigment, a dye, a dye improver, and the like. Depending on the case, it is also possible to add any additive.

  Therefore, the rutile-type titanium oxide ultrafine particles according to the present invention, or the composite inorganic oxide ultrafine particles composed of a coating layer containing one or more inorganic oxides with the ultrafine particles as core fine particles have a high refractive index and are transparent. The resin composition formed using the ultrafine particles has high refractive index, transparency, light resistance, weather resistance, heat resistance, molding processability, etc. The refractive index can be arbitrarily adjusted and is suitably used for an optical member.

  There is no restriction | limiting in particular in the optical member comprised including the resin composition of this invention, For example, it can use for all or one part of a member. More specifically, materials for high refractive index optical members such as optical lenses (glasses lenses, pickup lenses, etc.), optical prisms, optical waveguides, optical fibers, thin film molded products, optical adhesives, optical semiconductor sealing materials, etc. Can be mentioned.

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

(Preparation of tin-modified rutile titanium oxide ultrafine particles and sol solution)
[Production Example 1]
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 a white precipitate was collected. When 20 mL of ion-exchanged water (pH 6.2) was added and the pH was raised, it was redispersed. This was ultrafiltered to obtain a sol solution having a solid content of 2% by weight. It was rutile type titanium oxide when the powder X-ray-diffraction measurement was performed after performing hot-air drying for 2 hours at 120 degreeC. 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.

[Production Example 2]
The same operation as in Production Example 1 was carried out except that 0.9 g of tin tetrachloride pentahydrate was used in Production Example 1. (Sticking 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 Production Example 1, the average crystal diameter was 5 nm for the minor axis and 8 nm for the major axis, respectively. It was a rutile type titanium oxide having an average aggregated particle size of 20 nm. The element molar ratio of Sn / Ti was 0.06.

(Preparation of inorganic oxide-coated tin-modified rutile-type titanium oxide ultrafine particle sol solution)
[Production Example 3]
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 the 2 wt% tin-modified rutile-type titanium oxide ultrafine particle sol solution prepared in Production Example 1, 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.

[Production Example 4]
A sol solution was prepared in the same manner as in Production Example 3 except that the tin-modified rutile-type titanium oxide ultrafine particle sol solution prepared in Production Example 2 was used.

(Preparation of resin composition)
(Experimental example 1)
The sol solution obtained in Production Example 1 was replaced with methanol by an evaporator to obtain a 4 wt% sol solution. 50 g was taken out, 50 ml of acetic acid was added, and the mixture was stirred at room temperature for 60 hours. The precipitate was centrifuged and washed three times with ethyl acetate. The obtained cake was added in a wet state into 100 ml of 1-butanol, and sonication was carried out for 1 hour. To this was added 100 ml of toluene to obtain a solution in which ultrafine particles were uniformly dispersed. After adding 50 ml of n-hexylamine to this solution and stirring for 1 hour, the produced precipitate was collected by centrifugation, and then the operations of washing with methanol and centrifugation were repeated twice. In a solution in which the precipitate of acetic acid / hexylamine composite modified ultrafine particles is uniformly dispersed in 40 ml of chloroform, a separately prepared copolymer of purified bisphenol A and epichlorohydrin (manufactured by Sigma Aldrich Japan Co., Ltd.) A solution prepared by dissolving 2 g of pellets in 20 ml of chloroform was mixed and stirred for 30 minutes. A part of the solution was concentrated with an evaporator, and then cast and dried at 60 ° C. for a whole day and night to form a 2 mm thick film. The film was colorless and transparent. Further, a part of the solution was put into heptane, and the obtained white powder was dried under reduced pressure at 60 ° C. and hot-pressed to produce a colorless and transparent 2 mm thick film. (Fine particle / resin weight ratio = 0.5)

(Experimental example 2)
A resin composition was prepared in the same manner as in Experimental Example 1 except that the sol solution obtained in Production Example 2 was used.

(Experimental example 3)
A resin composition was prepared in the same manner as in Experimental Example 1 except that the sol solution obtained in Production Example 3 was used.

(Experimental example 4)
A resin composition was prepared in the same manner as in Experimental Example 1 except that the sol solution obtained in Production Example 4 was used.

(Experimental example 5)
The sol solution obtained in Production Example 3 was replaced with methanol by an evaporator to obtain a 4 wt% sol solution. 0.2 g of acrylic acid was added to 37.5 g of the sol solution (1.5 g of fine particles) and stirred. Furthermore, 1.3 g of a mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate (DPHA, manufactured by Nippon Kayaku Co., Ltd.), 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (TMDPO) as a photoinitiator 0.17 g was added, and the mixture was sufficiently stirred to remove the solvent, and irradiated with a metal halide lamp (strength 120 W / cm) for 60 seconds to form a 2 mm thick film. (Fine particle / resin weight ratio = 0.5)

(Experimental example 6)
A resin composition was prepared in the same manner as in Experimental Example 5 except that the sol solution obtained in Production Example 4 was used.

(Preparation of inorganic oxide-coated anatase-type titanium oxide ultrafine particle sol solution and resin composition)
(Production Example 5)
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 chloride 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. When the solid content of the obtained sol solution was analyzed in the same manner as in Example 1, it was anatase-type titanium oxide having an average of 5 nm on both the minor axis and the major axis. 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.

(Experimental example 7)
A resin composition was formed in the same manner as in Experimental Example 1 except that the sol solution obtained in Production Example 5 was used.

(Experimental example 8)
A resin composition was prepared in the same manner as in Experimental Example 5 except that the sol solution obtained in Experimental Example 7 was used.

(Synthesis of rutile titanium oxide, preparation of resin composition)
(Production Example 6)
It carried out like manufacture example 1 except not adding a tin tetrachloride pentahydrate. The white precipitate obtained did not redisperse. When analyzed in the same manner, it was a rutile type titanium oxide having an aggregate particle diameter of 200 nm or more.

(Experimental example 9)
A resin composition was formed in the same manner as in Experimental Example 1 except that the sol solution obtained in Production Example 6 was used.

  The refractive index of the ultrafine particles and resin composition prepared by the above method was evaluated as follows. The results are shown in Table 1.

(A) Measurement of refractive index:
Fine particle refractive index: 200 mg of polyvinylpyrrolidone added to a sol solution corresponding to a solid content of 0.2 g and further 10 g of ion-exchanged water are applied on a quartz substrate to a film thickness of about 700 mm by spin coating, and the coating film is 120 After drying at ° C., the measurement was performed immediately using an automatic wavelength scanning ellipsometer M-150 (manufactured by JASCO Corporation). The refractive index of the solid content was evaluated from the volume fraction of the contained solid content.
-Resin composition: The dissolved resin composition solution was applied on a quartz substrate by a spin coat method to a film thickness of about 700 mm, and a coating film dried with hot air was measured.

(Table 1)

  In addition, the light resistance of the inorganic oxide-coated tin-modified rutile-type titanium oxide ultrafine particles and the resin composition prepared by the above method was evaluated as follows. The results are shown in Table 2.

(B) Light resistance: The resin composition obtained was free from cracking, yellowing and browning after irradiation for 300 hours by a solar simulator (Type: sss-252161-ER manufactured by Ushio Electric Co., Ltd.). A.
A ... No change B ... Browning and cracking

(Table 2)

  In Experimental Examples 1 to 6, tin-modified rutile type titanium oxide ultrafine particles were used. As can be seen from the above results, the composite inorganic oxide ultrafine particles having a higher refractive index than the case of anatase-type titanium oxide by using tin-modified rutile titanium oxide ultrafine particles and having light resistance by coating with an inorganic oxide. It can be seen that a resin composition is obtained.

Claims (13)

From an inorganic oxide ultrafine particle having a refractive index of 1.5 to 2.8 containing titanium oxide having a rutile-type crystal structure, or from a coating layer containing the ultrafine particle as a core fine particle and containing one or more inorganic oxides A composite inorganic oxide ultrafine particle having a refractive index of 1.5 to 2.8,
A resin composition comprising:   The resin composition according to claim 1, wherein the rutile-type titanium oxide is titanium oxide having a tin-modified rutile-type crystal structure.   The resin composition of Claim 2 whose Sn / Ti composition molar ratio of the said ultrafine particle is 0.001 or more and 0.5 or less.   Coexistence of tin compounds in which the rutile titanium oxide ultrafine particles in the inorganic oxide ultrafine particles containing titanium oxide having the rutile crystal structure have a molar ratio of tin to titanium (Sn / Ti) of 0.001 to 2 The tin modification obtained by reacting a titanium compound aqueous solution having a Ti concentration of 0.07 to 5 mol / l in a pH range of −1 to 3 and having a Sn / Ti composition molar ratio of 0.001 to 0.5. The resin composition according to claim 1, wherein the resin composition is rutile-type titanium oxide ultrafine particles.   The content of titanium oxide having a rutile-type crystal structure contained in the inorganic oxide ultrafine particles is 5 to 100% by weight based on the weight of the inorganic oxide ultrafine particles. The resin composition in any one.   The content of the inorganic oxide ultrafine particles or the composite inorganic oxide ultrafine particles is 0.1 to 90% by weight based on the total weight of the resin composition. Resin composition.   The resin composition according to any one of claims 1 to 6, wherein the composite inorganic oxide ultrafine particle has a coating layer / core fine particle weight ratio of 1/99 to 90/10.   The resin composition according to any one of claims 1 to 7, wherein a minor axis and a major axis of the crystal diameter of the inorganic oxide ultrafine particles or the composite inorganic oxide ultrafine particles are 2 to 20 nm.   The resin composition according to any one of claims 1 to 8, wherein an average aggregate particle diameter of an aggregate composed of the inorganic oxide ultrafine particles or the composite inorganic oxide ultrafine particles is 10 to 100 nm.   The resin composition according to any one of claims 1 to 9, which is a sol in which the inorganic oxide ultrafine particles or the composite inorganic oxide ultrafine particles are dispersed in water or an organic solvent.   The resin composition according to any one of claims 1 to 10, having a refractive index of 1.5 to 2.8.   An optical member comprising the resin composition according to claim 1.   13. The optical member according to claim 12, wherein the optical member is used for an optical lens, an optical prism, an optical waveguide, an optical fiber, a thin film molding, an optical adhesive, or an optical semiconductor sealing material.