EP2257497A2 - Nanoparticules d'oxyde de titane dopées au moyen de métaux alcalins et/ou de métaux alcalino-terreux et procédé de production associé - Google Patents

Nanoparticules d'oxyde de titane dopées au moyen de métaux alcalins et/ou de métaux alcalino-terreux et procédé de production associé

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Publication number
EP2257497A2
EP2257497A2 EP09712673A EP09712673A EP2257497A2 EP 2257497 A2 EP2257497 A2 EP 2257497A2 EP 09712673 A EP09712673 A EP 09712673A EP 09712673 A EP09712673 A EP 09712673A EP 2257497 A2 EP2257497 A2 EP 2257497A2
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EP
European Patent Office
Prior art keywords
particles
titanium dioxide
nanoscale
alkali metal
metal compound
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP09712673A
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German (de)
English (en)
Inventor
Peter William De Oliveira
Thomas Müller
Michael Veith
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Leibniz Institut fuer Neue Materialien Gemeinnuetzige GmbH
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Leibniz Institut fuer Neue Materialien Gemeinnuetzige GmbH
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Publication of EP2257497A2 publication Critical patent/EP2257497A2/fr
Withdrawn legal-status Critical Current

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    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G23/00—Compounds of titanium
    • C01G23/04—Oxides; Hydroxides
    • C01G23/047—Titanium dioxide
    • C01G23/053—Producing by wet processes, e.g. hydrolysing titanium salts
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y30/00—Nanotechnology for materials or surface science, e.g. nanocomposites
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G23/00—Compounds of titanium
    • C01G23/003—Titanates
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09C—TREATMENT OF INORGANIC MATERIALS, OTHER THAN FIBROUS FILLERS, TO ENHANCE THEIR PIGMENTING OR FILLING PROPERTIES ; PREPARATION OF CARBON BLACK  ; PREPARATION OF INORGANIC MATERIALS WHICH ARE NO SINGLE CHEMICAL COMPOUNDS AND WHICH ARE MAINLY USED AS PIGMENTS OR FILLERS
    • C09C1/00—Treatment of specific inorganic materials other than fibrous fillers; Preparation of carbon black
    • C09C1/36—Compounds of titanium
    • C09C1/3607—Titanium dioxide
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D7/00—Features of coating compositions, not provided for in group C09D5/00; Processes for incorporating ingredients in coating compositions
    • C09D7/40—Additives
    • C09D7/60—Additives non-macromolecular
    • C09D7/61—Additives non-macromolecular inorganic
    • C09D7/62—Additives non-macromolecular inorganic modified by treatment with other compounds
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D7/00—Features of coating compositions, not provided for in group C09D5/00; Processes for incorporating ingredients in coating compositions
    • C09D7/40—Additives
    • C09D7/66—Additives characterised by particle size
    • C09D7/67—Particle size smaller than 100 nm
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2002/00—Crystal-structural characteristics
    • C01P2002/50—Solid solutions
    • C01P2002/52—Solid solutions containing elements as dopants
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2002/00—Crystal-structural characteristics
    • C01P2002/50—Solid solutions
    • C01P2002/52—Solid solutions containing elements as dopants
    • C01P2002/54—Solid solutions containing elements as dopants one element only
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/60—Particles characterised by their size
    • C01P2004/64—Nanometer sized, i.e. from 1-100 nanometer
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C08K3/18—Oxygen-containing compounds, e.g. metal carbonyls
    • C08K3/20—Oxides; Hydroxides
    • C08K3/22—Oxides; Hydroxides of metals

Definitions

  • the invention relates to nanoscale titanium dioxide particles having greatly reduced or suppressed photocatalytic activity, and to processes for their preparation. Furthermore, the invention relates to compositions containing these nanoscale particles and their use in optical materials.
  • Nanoscale particles play a major role in the production of optical materials.
  • optical materials having very high refractive indices can be produced.
  • Such materials are also referred to as composite materials.
  • the particles used usually consist of doped or undoped oxides, such as, for example, indium tin oxide (ITO), zirconium dioxide, barium titanate or titanium dioxide. Titanium dioxide in particular is used particularly frequently because of its good availability and its particularly high refractive index.
  • ITO indium tin oxide
  • titanium dioxide in particular is used particularly frequently because of its good availability and its particularly high refractive index.
  • brookite, rutile and anatase only the last two are of technical importance. By treatment with high temperatures anatase is convertible to rutile.
  • titanium dioxide Both are able to absorb UV light due to their electronic structure.
  • coatings or particles of titanium dioxide are often used as additives in UV-light-absorbing layers or compositions, for example in sunscreens. Due to the semiconductor properties of titanium dioxide, however, upon absorption of UV light, reactive electrons / hole pairs are formed which have a relatively long recombination time. Therefore, holes and electrons can migrate to the surface and be available there for chemical reactions. This property is also referred to as the photocatalytic activity or photocatalytic effect of titanium dioxide. According to one theory, the photocatalytic effect of anatase over rutile is much more pronounced due to its larger band gap of 3.05 eV (rutile) and 3.23 eV (anatase).
  • photocatalytic activity is used, for example, for the production of self-cleaning surfaces or for the purification of waste water.
  • the photocatalytic activity poses a major problem, as it leads, for example, to the decomposition of the matrix surrounding the particles.
  • documents WO 03/068682 and US 2005/0233146 describe doping with trivalent ions, for example Al 3+ , Fe 3+ , or Rh 3+ .
  • WO 99/060994 describes the doping with manganese or chromium ions.
  • sodium ions can disrupt the photocatalytic activity of titanium dioxide. This occurs, for example, when intentionally photocatalytic layers are applied to glass containing sodium ions and the sodium ions diffuse into the photocatalytic layer (DE 102 35 803, or WO 04/005577).
  • the size of the particles plays an important role for optical materials. Particles larger than 70 nm break the light and are therefore no longer transparent. In addition, as the surface area of smaller particles increases, so does their photocatalytic activity.
  • DE 102 35 803 or WO 04/005577 describes the preparation of redispersible nanoscale titanium dioxide particles which However, by lattice doping have an increased photocatalytic activity.
  • tin, ammonium or sodium salts in the conversion of amorphous titanium dioxide particles in the rutile modification is known for example from WO 03/068682, or US 2005/0233146, but there they serve to reduce the particle size, while the particles themselves are doped with aluminum ions.
  • a lattice doping with sodium ions for the reduction of the photocatalytic activity is not described.
  • the object of the invention is to provide nanoscale titanium dioxide particles, wherein the photocatalytic activity is reduced by the lattice doping or completely suppressed.
  • the particles should additionally be redispersible to primary particle size and produced by simple and inexpensive processes.
  • nanoscale titanium dioxide particles have at least one or more alkali metal ions and / or or alkaline earth metal ions contain one kind of alkali metal and / or alkaline earth metal ions.
  • doping means a proportion of up to 30 mol% of dopant in titanium dioxide, based on titanium.
  • the proportion of doping is preferably between 0.01 to 30 mol .-%, preferably between 1 to 15 mol .-%.
  • the particles according to the invention are redispersible to primary particle size. As stated above, this is necessary for incorporation in plastics, for example.
  • the alkali metal ions and / or alkaline earth metal ions are advantageously selected from the group comprising sodium, potassium, lithium, calcium and magnesium ions; preference is given to sodium, potassium and lithium ions, particularly preferably sodium ions.
  • the particles of the invention may be present as anatase.
  • the particle-containing composite materials or preparations according to the invention can be shaped by shaping processes known to those skilled in the art, such as, for example, film casting, extrusion on, electrophoresis, injection molding and pressing.
  • they can also be surface-modified, for example with polymerizable or hydrophobic groups. This is known from the prior art.
  • nanoscale particles of the invention are prepared by the following process:
  • the hydrolyzable titanium compound is in particular a compound of the formula TiX ⁇ in which the hydrolyzable groups X, which are different or preferably identical to one another, for example hydrogen, halogen (F, Cl, Br or I, in particular Cl and Br), alkoxy (preferably Ci- 6 - alkoxy, in particular Ci-4-alkoxy, such as methoxy, ethoxy, n-propoxy, i-propoxy, butoxy, i-butoxy, se ⁇ .-butoxy and tert-butoxy), aryloxy (preferably C 6 -i 0 -aryloxy, such as phenoxy), Acyloxy (preferably CI_ 6 acyloxy such as acetoxy or propionic onyloxy) or alkylcarbonyl (preferably C 2 - 7 alkyl-carbonyl such as acetyl), respectively.
  • halogen F, Cl, Br or I, in particular Cl and Br
  • alkoxy preferably Ci- 6 - alkoxy, in particular Ci
  • halide is TiCl 4 .
  • Preferred hydrolysable groups X are alkoxy groups, in particular Ci- 4 alkoxy.
  • Concrete and preferably used titanates are Ti (OCH 3 ) 4 , Ti (OC 2 H 5 ) 4 and Ti (n- or i-OC 3 H 7 ) 4 .
  • the solvent use is made of an organic solvent in which the hydrolyzable titanium compound is preferably soluble.
  • the solvent is also preferably miscible with water.
  • suitable organic solvents include alcohols, ketones, ethers, amides and mixtures thereof.
  • Alcohols are preferably used, preferably lower aliphatic alcohols (C 1 -C 6 -alkyl), such as ethanol, 1-propanol, i-propanol, sec. Butanol, tert. Butanol, isobutyl alcohol, n-
  • butanol and the pentanol isomers especially 1-pentanol, with 1-propanol and 1-pentanol are particularly preferred.
  • the mixture also contains water in a substoichiometric amount relative to the hydrolyzable groups of the titanium compound, i. based on 1 mole of hydrolyzable groups in the titanium compound, less than one mole of water is present.
  • water in a substoichiometric amount relative to the hydrolyzable groups of the titanium compound, i. based on 1 mole of hydrolyzable groups in the titanium compound, less than one mole of water is present.
  • water in a substoichiometric amount relative to the hydrolyzable groups of the titanium compound, i. based on 1 mole of hydrolyzable groups in the titanium compound, less than one mole of water is present.
  • water in a substoichiometric amount relative to the hydrolyzable groups of the titanium compound, i. based on 1 mole of hydrolyzable groups in the titanium compound, less than one mole of water is present.
  • a hydrolyzable titanium compound having 4 hydrolyzable groups based on 1 mole of
  • the mixture also contains a catalyst for the hydrolysis and condensation under sol-gel conditions, in particular an acidic condensation catalyst, for example hydrochloric acid, phosphoric acid or formic acid.
  • a catalyst for the hydrolysis and condensation under sol-gel conditions in particular an acidic condensation catalyst, for example hydrochloric acid, phosphoric acid or formic acid.
  • alkali metal compound and / or alkaline earth compound all compounds suitable for doping can be used, with advantage the compounds used are not basic.
  • the hydrolysis of the titanium compound takes place under acidic conditions. If basic compounds raise the pH of the mixture too much, there is a strong growth of the resulting titanium dioxide particles and it is no longer possible to obtain particles according to the invention.
  • Basic compounds are compounds which contain anions of acids having a pKa value of greater than 15, for example alkoxides or hydroxides.
  • the alkali metal and / or alkaline earth metal compounds used are ionic, ie they are present as salts, wherein it also includes complex compounds.
  • Preferred cations are sodium, potassium, lithium, magnesium, and / or calcium ions, more preferably sodium ions.
  • Preferred anions are halides, in particular chloride or bromide, sulfate, hydrogen sulfate, sulfite, hydrogen sulfite, nitrate, nitrite, sulfide, phosphate, hydrogen phosphate, carbonate, bicarbonate, cyanide, thiocyanate, isocyanate or anions of the oxo acids of the halides, such as perchlorate.
  • anions are the anions NEN of mono- and polycarboxylic acids (carboxylates), such as formate, acetate, oxalate, stearate, oleate or 3, 6, 9-trioxodecanate.
  • carboxylates such as formate, acetate, oxalate, stearate, oleate or 3, 6, 9-trioxodecanate.
  • Alkali halides and alkali salts of the fatty acids are preferred. Particularly preferred are sodium chloride, sodium acetate, sodium formate, sodium oleate and sodium 3, 6, 9-trioxodecanat.
  • the quantitative ratio between the alkali metal and / or alkaline earth metal compounds provided for doping is between 0.0005: 1 to 0.3: 1, preferably 0.001: 1 to 0.2: 1 , more preferably 0.005: 1 to 0.2: 1.
  • the resulting mixture is then treated at a temperature of at least 60 ° C. to form a dispersion or precipitate of doped titanium dioxide particles.
  • This heat treatment is preferably carried out hydrothermally or by heating under reflux. It is expedient to use a relatively high dilution in the heat treatment, in particular when heating under reflux.
  • the heat treatment is preferably carried out over a period of at least 1 h to 30 h, preferably at least 4 h to 24 h, the duration depending on the temperature and an optionally applied pressure.
  • Heating under reflux is carried out suitably above ei ⁇ NEN period of at least 16 hours, for example, if 1-pentanol is used as a solu- solvents.
  • the hydrothermal, lyothermal or solvothermal treatment is used.
  • Under a Lyothermal treatment is generally understood a heat treatment of a solution or suspension under pressure, for. Example, at a temperature above the boiling point of the solvent and a pressure above 1 bar.
  • a hydrothermal process In the special case of an aqueous solution or suspension, the process is referred to as a hydrothermal process.
  • a heat treatment in a predominantly organic solvent, which contains little water at all under pressure as a hydrothermal treatment.
  • the mixture is heat treated in a pressure vessel or autoclave.
  • the treatment is preferably carried out at a temperature in the range of 75 0 C to 300 0 C, preferably above 200 0 C, more preferably from 225 0 C to 275 0 C, for example about 250 0 C.
  • a pressure is built up in the closed container or autoclave (autogenous pressure).
  • the pressure obtained can be, for example, more than 1 bar, in particular 50 to 500 bar or more, preferably 100 to 300 bar, for example 200 bar.
  • the hydrothermal treatment is carried out for at least 1 h and preferably for at least 6 h to 7 h.
  • step c) The heat treatment according to step c) is carried out until the desired doped titanium dioxide particles are formed.
  • the dispersion or the precipitate can be further processed directly or after a solvent exchange, for example for coating compositions.
  • a solvent exchange for example for coating compositions.
  • To obtain the powder of titanium dioxide particles, as well as the Solvent replacement removes the solvent. Methods of removing the solvent are described below.
  • the resulting doped titanium dioxide particles of the dispersion, the precipitate or the powder are predominantly crystalline in the anatase form.
  • the crystalline content of the resulting doped titanium dioxide particles is greater than 90%, preferably greater than 95%, and most preferably greater than 97%, i. the amorphous portion is in particular below 3%, e.g. at 2%.
  • the average particle size is preferably not more than 20 nm, more preferably not more than 10 nm. In a particularly preferred embodiment, particles having an average particle size of about 2 to 10 nm are obtained.
  • the titanium dioxide particles have a particularly homogeneous distribution of the doping metals.
  • the particles In order to obtain the particles as powders, it is necessary to separate the particles, which are present as a dispersion, from the solvent. All methods known to the person skilled in the art can be used for this purpose. Centrifugation is particularly suitable. The separated titanium dioxide particles are then dried (eg at 40 0 C and 10 mbar). In this form, the particles can also be stored well.
  • the dispersion obtained can also be further processed as such without removal of the solvent, for example for producing a composition for coatings.
  • a solvent exchange Suitable for this purpose are, for example, the abovementioned solvents or water.
  • a water / alcohol mixture and more preferably water alone is used as the solvent.
  • titanium dioxide doped with alkali metal and / or alkaline earth metal ions is readily available in just a few steps. According to the application, both the degree and the type of doping can be easily controlled.
  • the particles are available for all types of further processing known to the person skilled in the art. For example, surface modifications can be introduced or coatings applied to the particles.
  • nanoscale particles according to the invention are preferably obtainable by this process presented. This method is particularly suitable for the production of titanium dioxide particles according to the invention in the anatase modification.
  • the titanium dioxide particles according to the invention can be reacted with the aid of surface-modifying agents in order to supplement them with functional groups.
  • particles can be provided with desired properties as needed.
  • they can be improved compared to other materials with which they are to be mixed, if appropriate, for improved compatibility.
  • hydrophobic or hydrophilic properties can be introduced.
  • one or more functional groups are introduced on the surface of the particles via the functional group. These then also allow, for example, reactions with other materials or between the particles. Particular preference is given to functional onelle groups that are suitable for the crosslinking reactions.
  • the particles of the invention are reacted with a surface modifier. These are known processes, as described by the applicant eg in DE 102 35 803 or WO 04/005577.
  • the invention also includes a composition containing the particles of the invention and an organic, inorganic or organically modified inorganic matrix-forming material.
  • These may in particular be inorganic sols or organically modified inorganic hybrid materials or nanocomposites.
  • examples of these are optionally organically modified oxides, hydrolyzates and (poly) condensates of at least one glass- or ceramic-forming element M, in particular an element M from the Grup ⁇ pen 3 to 5 and / or 12 to 15 of the Periodic Table of the Elements, preferably Si, Al, B, Ge, Pb, Sn, Ti, Zr, V and Zn, especially those of Si and Al, most preferably Si, or mixtures thereof.
  • a preferred organically modified inorganic hybrid material is polyorganosiloxanes.
  • hydrolysates of glass- or ceramic-forming elements, in particular of silicon are particularly preferred.
  • the inorganic or organically modified inorganic matrix-forming material is preferably added in an amount such that the molar ratio of titanium of the titanium dioxide particles to glass-forming or ceramic-forming element M is 100: 0.01 to 0.01: 100, preferably 300: 1 to 1: 300. Very good results are obtained at a Ti / M molar ratio of about 10: 3 to 1:30 received. If an organically modified inorganic matrix-forming material is used, all or only part of the contained glass- or ceramic-forming elements M may have one or more organic groups as nonhydrolyzable groups.
  • the inorganic or organically modified inorganic matrix-forming materials can be prepared by known methods, e.g. by flame pyrolysis, plasma processes, gas-phase condensation processes, colloid techniques, precipitation processes, sol-gel processes, controlled nucleation and growth processes, MOCVD processes and (micro) emulsion processes. If solvent-free particles are obtained from the process, they are suitably dispersed in a solvent. Methods are described in detail in the prior art.
  • the inorganic sols and in particular the organically modified hybrid materials are obtained by the sol-gel method.
  • the sol-gel process usually hydrolyzable compounds are hydrolyzed with water, optionally with acidic or basic catalysis, and optionally at least partially condensed.
  • the hydrolysis and / or condensation reactions lead to the formation of compounds or condensates with hydroxyl, oxo groups and / or oxo bridges, which serve as precursors. It is possible to use stoichiometric amounts of water, but also smaller or larger quantities.
  • the forming sol can be adjusted by suitable parameters, eg degree of condensation, solvent or pH, to the viscosity desired for the coating composition. Further details of the sol-gel process are, for example, in CJ. Brinker, GW Scherer: "Sol-Gel Science - The Physics and Chemistry of Sol-Gel Processing ", Academic Press, Boston, San Diego, New York, Sydney (1990).
  • the oxides, hydro lysates or (poly) condensates are obtained by hydrolysis and / or condensation from hydrolyzable compounds of the abovementioned glass- or ceramic-forming elements, which may additionally be used to prepare the organically-modified inorganic hybrid material bear nonhydrolyzable organic substituents.
  • Inorganic sols are formed according to the sol-gel process in particular from hydrolyzable compounds of the general formulas MX n , wherein M is the above-defined glass or ceramic-forming element, X is defined as in the following formula (I), wherein two groups X by an oxo group may be replaced, and n corresponds to the valence of the element and is usually 3 or 4. It is preferably hydrolyzable Si compounds, in particular the following formula (I).
  • Examples of usable hydrolyzable compounds of elements M other than Si are Al (OCHa) 3 , Al (OC 2 Hs) 3 , Al (ODC 3 H 7 ) 3, Al (OiC 3 H 7 ) 3, Al ( OHC 4 Hg) 3 , Al (O-SeJc.C 4 Hg) 3 , AlCl 3 , AlCl (OH) 2 , Al (OC 2 H 4 OC 4 Hg) 3 , TiCl 4 , Ti (OC 2 H 5 ) 4 , Ti (O-nC 3 H 7 ) 4 , Ti (0-1 C 3 H 7 ) 4 , Ti (OC 4 Hg) 4 , Ti (2-ethylhexoxy) 4 , ZrCl 4 , Zr (OC 2 Hs ) 4 , Zr (O-HC 3 H 7 ) 4 , Zr (O-C 3 H 7 ) 4 , Zr (OC 4 Hg) 4 , ZrOCl 2 , Zr (2-ethyl
  • the sol or the organically modified inorganic hybrid material is obtained from one or more hydrolyzable and condensable silanes, optionally wherein at least one silane has a non-hydrolyzable organic radical.
  • silanes having the following general formulas (I) and / or (II) are particularly preferably used:
  • radicals X are identical or different and denote hydrolyzable groups or hydroxyl groups
  • R is the same or different and represents a non-hydrolyzable radical which optionally has a functional group
  • X has the abovementioned meaning and a is 1, 2 or 3, preferably 1 or 2, has.
  • the hydrolyzable groups X are, for example, hydrogen or halogen (F, Cl, Br or I), alkoxy (preferably C ⁇ - 6 -alkoxy, such as methoxy, ethoxy, n-propoxy, i-propoxy and butoxy), aryloxy (preferably C 6 -io ⁇ aryloxy, such as phenoxy), acyloxy (preferably Ci 6 acyloxy such as acetyl Toxy or propionyloxy), alkylcarbonyl (preferably C 2 - 7 - alkylcarbonyl, such as acetyl), amino, monoalkylamino or dialkylamino having preferably 1 to 12, in particular 1 to 6, carbon atoms in the alkyl group (s).
  • alkoxy preferably C ⁇ - 6 -alkoxy, such as methoxy, ethoxy, n-propoxy, i-propoxy and butoxy
  • aryloxy preferably C 6 -io ⁇ aryloxy, such as
  • the non-hydrolyzable radical R is, for example, alkyl (preferably C 1-6 -alkyl, such as, for example, methyl, ethyl, n-propyl, isoproyl). pyl, n-butyl, s-butyl and t-butyl, pentyl / hexyl or cyclohexyl xyl), alkenyl (preferably C 2 - 6 alkenyl, such as vinyl, 1-propenyl, 2-propenyl and butenyl), alkynyl ( preferably C 2-6 -alkynyl, such as, for example, acetylenyl and propargyl) and aryl (preferably C 1-10 -aryl, such as, for example, phenyl and naphthyl).
  • alkyl preferably C 1-6 -alkyl, such as, for example, methyl, ethyl, n-propyl, iso
  • radicals R and X mentioned may optionally contain one or more customary substituents, e.g. Halogen, ether, phosphoric acid, sulfonic acid, cyano, amide-mercapto, thioether or alkoxy groups, as having functional groups.
  • substituents e.g. Halogen, ether, phosphoric acid, sulfonic acid, cyano, amide-mercapto, thioether or alkoxy groups, as having functional groups.
  • the radical R may contain a functional group via which crosslinking is possible.
  • Specific examples of the functional groups of the radical R are epoxy, hydroxyl, amino, monoalkylamino, dialkylamino, carboxy, allyl, vinyl, acryl, acryloxy, methacrylic, methacryloxy, cyano , Aldehyde and alkylcarbonyl groups. These groups are preferably bonded to the silicon atom via alkylene, alkenylene or arylene bridging groups which may be interrupted by oxygen or sulfur atoms or -NH groups.
  • the bridging groups mentioned are derived, for example, from the abovementioned alkyl, alkenyl or aryl radicals.
  • the bridging groups of the radicals R preferably contain 1 to 18, in particular 1 to 8, carbon atoms.
  • Particularly preferred hydrolyzable silanes of the general formula (I) are tetraalkoxysilanes, such as tetramethoxysilane and in particular tetraethoxysilane (TEOS).
  • TEOS tetraethoxysilane
  • Particularly preferred organosilanes of the general formula (II) are epoxysilanes such as 3-glycidyloxypropyltrimethoxysilane (GPTS), methacryloxypropyltri- methoxysilane and acryloxypropyltrimethoxysilane, wherein GPTS hydrolyzates can be used with advantage.
  • GPTS 3-glycidyloxypropyltrimethoxysilane
  • methacryloxypropyltri- methoxysilane and acryloxypropyltrimethoxysilane wherein GPTS hydroly
  • silanes of the formula (II) or a mixture of silanes of the formula (I) and (II) can be used.
  • silanes of the formula (I) are used, with proportionally hydrolyzable compounds of the above formula MX n being added, if appropriate.
  • the inorganic sol consists of disperse oxide particles dispersed in the solvent, they can improve the hardness of the layer. These particles are, in particular, nanoscale inorganic particles.
  • the particle size (X-ray-determined volume average) is e.g. in the range of less than 200 nm, in particular less than 100 ntn, preferably less than 50 nm, e.g. 1 nm to 20 nm.
  • inorganic sols of SiO 2 , ZrO 2 , GeO 2 , CeO 2 , ZnO, Ta 2 O 5 , SnO 2 and Al 2 O 3 (in all modifications, especially as boehmite AlO (OH)), preferably brine of SiO 2 , Al 2 O 3 , ZrO 2 , GeO 2 and mixtures thereof may be used as nanoscale particles.
  • sols are also commercially available, for example, silica sols such as the Levasile® from HC Starck.
  • inorganic or organically modified inorganic matrix-forming material it is also possible to use a combination of such nanoscale particles as hydrolyzates or
  • Iy condensates present inorganic sols or organically modified hybrid materials can be used, which is referred to herein as nanocomposites.
  • organic monomers, oligomers or polymers of all kinds may also be included as organic matrix-forming materials which serve as flexibilizers, which may be conventional organic binders. These can be used to improve coatability.
  • the oligomers and polymers may have functional groups through which crosslinking is possible. This possibility of crosslinking is also possible in the case of the above-described organically modified inorganic matrix-forming materials. Mixtures of inorganic, organically modified inorganic and / or organic matrix-forming materials are also possible.
  • Examples of useful organic matrix-forming materials are polymers and / or oligomers which have polar groups, such as hydroxyl, primary, secondary or tertiary amino, carboxyl or carboxylate groups.
  • Typical examples are polyvinyl alcohol, polyvinylpyrrolidone, polyacrylamide, polyvinylpyridine, polyallylamine, polyacrylic acid, polyvinylacetate, polymethylmethacrylic acid, starch, gum arabic, other polymeric alcohols such as e.g. Polyethylene-polyvinyl alcohol copolymers, polyethylene glycol, polypropylene glycol and poly (4-vinylphenol) or monomers or oligomers derived therefrom.
  • the composition may be, for example, a coating composition, a molding composition, a resin composition, paste, solution or cream.
  • a coating composition the usual methods can be used, for example dipping, rolling, knife coating, flooding, drawing, spraying, spinning or brushing on.
  • the applied dispersion is optionally dried and heat treated, such as for hardening or compaction. Due to the reduced or suppressed photocatalytic activity of the titanium dioxide particles, it is also possible to coat sensitive substrates such as plastics directly.
  • the heat treatment used depends on the substrate. Naturally, very high temperatures can not be used with plastic substrates or plastic surfaces.
  • PC polycarbonate
  • the heat treatment is carried out, for example, at a temperature of 100 to 200 0 C and, if no plastic is present, up to 500 0 C or more.
  • the heat treatment takes place, for example, for 15 minutes to 2 hours.
  • layer thicknesses of 50 nm to 30 ⁇ m are obtained, preferably 100 nm to 1 ⁇ m, for example 50 to 700 nm.
  • one or more coating compositions according to the invention can also be used in combination with other coatings.
  • the inorganic sol or the organically-modified inorganic hybrid material serves not only as a matrix-forming material but also for improved layer adhesion. Titanium dioxide may be present in the layer as a matrix-forming component and / or as a particle.
  • compositions may also be cast into molds and used to make moldings.
  • the nanoscale titanium dioxide particles according to the invention have a high refractive index, which can be slightly reduced by the doping. Their good redispersibility and their reduced or suppressed photocatalytic activity make them suitable for many applications, especially when high refractive indices are required, for example for the production of high-index composite materials. At the same time they are easily accessible through the two specified methods.
  • the particles according to the invention can be used, for example, in refractive or diffractive optical elements, lenses, films, holographic materials, optical waveguides, UV-absorbing coatings, UV-absorbing compositions, such as sunscreens, or pigments.
  • composition according to the invention can be used in optical elements, lenses, films, holographic materials, optical waveguides, UV-absorbing coatings, UV-absorbing compositions, such as sunscreens, or pigments.
  • the matrix used for this purpose can be adapted according to the desired properties.
  • area information always includes all - not mentioned - intermediate values and all imaginable subintervals.
  • suspensions of 1 g of TiO.sub.2 particles in 19 g of a mixture of ethanol / water 1: 1 were prepared with the aid of 1 g of 3,6,9-trioxadecanoic acid as a dispersion aid. These were coated in a dip coating process at a pull rate of 2 mm / s onto suitable glass substrates (eg microscope slides, giving a coated area of approximately 9.25 cm 2 ) and cured at 300 ° C. for 1 h.
  • a coated substrate in a 50 ml aqueous solution of 50 .mu.mol / 1 4-CP contained subjected to irradiation over a period of 60 h in an Atlas Suntester CPS + solar simulator by means of a 750 W xenon arc lamp.
  • the concentration of the 4-CP at the beginning and at the end of an experiment rimentes was determined by UV-vis spectroscopy (Varian Cary 5000).
  • An active control sample showed a 50% reduction in 4-CP content in the course of such an experiment.
  • the reduction of the 4-CP content was in the range of 14-20%, depending on the sodium concentration used to prepare the particles; for non-titania titania, a photolysis reduction of 15% was noted.

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Abstract

L'invention concerne des particules de dioxyde de titane nanoscalaires à activité photocatalytique fortement réduite ou supprimée, ainsi que des procédés de production desdites particules. L'invention concerne également des compositions contenant lesdites particules nanoscalaires ainsi que leur utilisation dans des matériaux optiques.
EP09712673A 2008-02-22 2009-02-17 Nanoparticules d'oxyde de titane dopées au moyen de métaux alcalins et/ou de métaux alcalino-terreux et procédé de production associé Withdrawn EP2257497A2 (fr)

Applications Claiming Priority (2)

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DE102008010663A DE102008010663A1 (de) 2008-02-22 2008-02-22 Alkalimetall und/oder Erdalkalimetall dotierte Titanoxid-Nano-Partikel sowie Verfahren zu deren Herstellung
PCT/EP2009/001113 WO2009103489A2 (fr) 2008-02-22 2009-02-17 Nanoparticules d'oxyde de titane dopées au moyen de métaux alcalins et/ou de métaux alcalino-terreux et procédé de production associé

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CN109790100B (zh) * 2016-09-30 2023-02-17 大金工业株式会社 羧酸盐或磺酸盐以及表面活性剂
US20230312944A1 (en) 2020-08-21 2023-10-05 Basf Se Uv-curable coatings having high refractive index
CN115463542B (zh) * 2022-10-08 2023-10-27 南京大学 一种利用金属单原子修饰的氧化锌纳米颗粒高效光催化烃类小分子气体或甲醛降解的方法

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DE10205920A1 (de) 2002-02-12 2003-08-21 Itn Nanovation Gmbh Nanoskaliger Rutil, sowie Verfahren zu dessen Herstellung
AU2003246667A1 (en) 2002-07-09 2004-01-23 Institut Fur Neue Materialien Gemeinnutzige Gmbh Substrates comprising a photocatalytic tio2 layer
DE10235803A1 (de) 2002-08-05 2004-02-19 Institut für Neue Materialien Gemeinnützige GmbH Substrate mit photokatalytischer TIO2-Schicht
DE102004021425A1 (de) * 2004-04-30 2005-11-24 Institut für Neue Materialien Gemeinnützige GmbH Verwendung photokatalytischer TiO2-Schichten zur Funktionalisierung von Substraten

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