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EP1979421A2 - PARTICULES PIGMENTAIRES DE DIOXYDE DE TITANE POURVUES D'UN ENROBAGE DE SiO2 DOPÉ ET DENSE ET PROCÉDÉ DE FABRICATION DE CES PARTICULES - Google Patents

PARTICULES PIGMENTAIRES DE DIOXYDE DE TITANE POURVUES D'UN ENROBAGE DE SiO2 DOPÉ ET DENSE ET PROCÉDÉ DE FABRICATION DE CES PARTICULES

Info

Publication number
EP1979421A2
EP1979421A2 EP07703117A EP07703117A EP1979421A2 EP 1979421 A2 EP1979421 A2 EP 1979421A2 EP 07703117 A EP07703117 A EP 07703117A EP 07703117 A EP07703117 A EP 07703117A EP 1979421 A2 EP1979421 A2 EP 1979421A2
Authority
EP
European Patent Office
Prior art keywords
sio
doping
titanium dioxide
pigment particles
doped
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Withdrawn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
EP07703117A
Other languages
German (de)
English (en)
Inventor
Lydia Rews-Nicolai
Siegfried Bluemel
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.)
Kronos International Inc
Original Assignee
Kronos International Inc
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Kronos International Inc filed Critical Kronos International Inc
Publication of EP1979421A2 publication Critical patent/EP1979421A2/fr
Withdrawn legal-status Critical Current

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Classifications

    • 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
    • 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
    • C09C1/3653—Treatment with inorganic compounds
    • C09C1/3661—Coating
    • 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
    • C01P2004/80—Particles consisting of a mixture of two or more inorganic phases
    • C01P2004/82—Particles consisting of a mixture of two or more inorganic phases two phases having the same anion, e.g. both oxidic phases
    • C01P2004/84—Particles consisting of a mixture of two or more inorganic phases two phases having the same anion, e.g. both oxidic phases one phase coated with the other
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/24—Structurally defined web or sheet [e.g., overall dimension, etc.]
    • Y10T428/24355—Continuous and nonuniform or irregular surface on layer or component [e.g., roofing, etc.]
    • Y10T428/24372—Particulate matter
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/24—Structurally defined web or sheet [e.g., overall dimension, etc.]
    • Y10T428/24355—Continuous and nonuniform or irregular surface on layer or component [e.g., roofing, etc.]
    • Y10T428/24372—Particulate matter
    • Y10T428/2438—Coated
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/24—Structurally defined web or sheet [e.g., overall dimension, etc.]
    • Y10T428/24355—Continuous and nonuniform or irregular surface on layer or component [e.g., roofing, etc.]
    • Y10T428/24372—Particulate matter
    • Y10T428/2438—Coated
    • Y10T428/24388—Silicon containing coating
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/29—Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
    • Y10T428/2982—Particulate matter [e.g., sphere, flake, etc.]
    • Y10T428/2991—Coated

Definitions

  • the invention relates to titanium dioxide pigment particles, the surface of which is provided with a dense silicon dioxide shell doped with doping elements, and to methods for the production.
  • the titanium dioxide pigment particles according to the invention have improved photostability.
  • Titanium dioxide because of its high refractive index, is used as a high-quality pigment in many fields, e.g. Plastics, coatings, paper, fibers used.
  • titanium dioxide is photoactive, i. UV absorption causes undesirable photocatalytic reactions which lead to decomposition of the pigmented material [The Chemical Nature of Chalking in the Presence of Titanium Dioxide Pigments, H.G. Völz, G. Kaempf, H.G. Fitzky, A. Klaeren, ACS Symp. Ser. 1981, 151, Photodegradation and Photostabilization of Coatings].
  • titanium dioxide pigments absorb light in the near ultraviolet range, so that electron-hole pairs are generated which lead to the formation of highly reactive radicals on the titanium dioxide surface.
  • This shell is intended to prevent free radicals from forming on the particle surface.
  • SiO 2 dense skin treatments are also performed to increase the abrasion resistance of such coated glass fibers and to reduce the lubricity of the fibers in the products produced.
  • US Pat. No. 2,913,419 describes a wet-chemical process in which silica together with polyvalent metal ions such as Cu, Ag, Ba, Mg, Be, Ca, Sr, Zn, Cd, Al, Ti, Zr, Sn, Pb, Cr , Mn, Co, Ni is precipitated on the particle surface.
  • EP 1 042 408 B1 describes a gas phase process for surface coating with Si and B, P, Mg, Nb or Ge oxide.
  • the invention is also based on the object of specifying a production method for this pigment.
  • the object is achieved by titanium dioxide pigment particles whose surface is coated with a dense SiO 2 -HuIIe deposited from the gas phase and doped with at least one doping element, the SiO 2 -HII being characterized thereby; in that the doping with the at least one doping element lowers the energy state densities in the valence band and / or in the conduction band near the band gap or generates additional energy states in the band gap and doping elements from the group AI, B, Ge, Mg, Nb, P and Zr excluded are.
  • the object is further achieved by titanium dioxide pigment particles whose surface is coated with a dense SiO 2 -HuIIe deposited from the gas phase and doped with at least one doping element, wherein the doping element is selected from the group Sn, Sb, In, Y, Zn , F, Mn, Cu, Mo, Cd, Ce, W and Bi and mixtures thereof.
  • the doping element is selected from the group Sn, Sb, In, Y, Zn , F, Mn, Cu, Mo, Cd, Ce, W and Bi and mixtures thereof.
  • the object is further achieved by titanium dioxide pigment particles whose surface is coated with a dense SiO 2 -HIII generated by a wet process and doped with at least one doping element, the SiO 2 -HII being characterized thereby; in that the doping with the at least one doping element lowers the energy state densities in the valence band and / or in the conduction band near the band gap or generates additional energy states in the band gap and doping elements from the group Ag, Al, B, Ba, Be, Ca, Cd , Co, Cr, Cu, Mg, Mn, Ni, Pb, Sn, Sr, Ti, Zn and Zr are excluded.
  • the object is further achieved by titanium dioxide pigment particles whose surface is coated with a dense SiO 2 -HIII generated by a wet process and doped with at least one doping element, the doping element being selected from the group Sb, In, Ge, Y, Nb , F, Mo, Ce, W and Bi and mixtures thereof.
  • the object is further achieved by a process for producing titanium dioxide pigment particles whose surface is coated with a dense SiO 2 -HuIIe doped with at least one doping element, comprising the steps: a) reacting titanium tetrachloride in the gas phase with an aluminum halide and an oxygen containing gas in a reactor at a temperature above 1000 0 C to provide a particle stream containing TiO 2 particles, b) contacting the particle stream with at least two compounds, wherein the first compound is a silica precursor compound and the second compound is selected from the group consisting of oxide precursor compounds of Sn, Sb, In, Y, Zn, Mn, Cu 1 Mo, Cd, Ce, W, Bi and precursor compounds of F and mixtures thereof, c) cooling the particle stream to pigment particles to be provided, which are coated with a doped with at least one doping element dense SiO 2 -HuIIe, preferably i die Doping elements are selected from the group Sn, Sb, In, Y 1 Zn, F,
  • another object of the invention is a process for the production of titanium dioxide pigment particles whose surface is coated with a dense SiO 2 -HuIIe doped with at least one doping element, comprising the steps of: a) providing an aqueous suspension of TiO 2 particles a pH above 10, b) adding an aqueous solution of an alkaline silicon component and at least one aqueous solution of a dopant-containing component, wherein the doping element is selected from the group Sb, In, Ge, Y, Nb, F, Mo , Ce, W and Bi and mixtures thereof, c) depositing a doped with at least one dopant dense SiO 2 -HCiIIe on the particle surface by lowering the pH of the suspension to a value below 9, preferably below 8, wherein the doping elements selected are from the group Sb, In, Ge, Y, Nb, F, Mo, Ce, W and Bi and mixtures.
  • the invention relates to coated titanium dioxide pigments which are further improved in terms of their photostability.
  • the pigments of the invention contain in a dense skin on the
  • Titanium dioxide particle surface 0.1 to 6.0 wt.%, Preferably 0.2 to 4.0 wt.% Silicon, calculated as SiO 2 and 0.01 to 3.0 wt.%, Preferably 0.05 to 2, 0% by weight
  • the particles are with an additional layer of
  • alumina or alumina hydrate calculated as Al 2 O 3 and based on the total pigment coated.
  • the titanium dioxide particles are preferably rutile.
  • the term "doping element” is understood as meaning both the respective element as atom or ion and also a corresponding compound such as, for example, an oxide, as far as applicable. here and below also the corresponding hydrous oxides or to understand the corresponding hydrates. All data disclosed below with regard to pH, temperature, concentration in% by weight or% by volume etc. are to be understood as meaning that all values which are within the range of the respective measuring accuracy known to the person skilled in the art are included.
  • the invention is based on the fact that to increase the photostability of the photocatalytic process must be interrupted in a suitable manner, i. that the generation of highly reactive radicals by excited electron-hole pairs must be made more difficult. This can be done using various mechanisms, for example by increasing the recombination rate of the electron-hole pairs or by building an energetic barrier at the pigment surface.
  • a dense and uniformly applied SiO 2 -HuIIe already builds an energetic barrier at the TiO 2 surface, detectable by a reduced energy state density near the band gap in the valence band and in the conduction band of the coated TiO 2 surface compared to the uncoated TiO 2 surface.
  • the doping of the SiO 2 -HuIIe with selected elements leads to further reduced energy state densities near the band gap, which increases the energy barrier and thus further improves the photostability of TiO 2 pigment thus coated.
  • Additional energy states within the band gap between valence band and conduction band favor the recombination of electron-hole pairs.
  • the doping of the SiO 2 coating with selected elements generates these energy states and thus likewise brings about an improvement in the photostability in comparison to the undoped SiO 2 layer.
  • the elements Sn, Sb, In, Ge, Y, Zr, Zn, Nb, F, Mn, Cu, Mo, Cd, Ce, W and Bi have proved to be suitable doping elements.
  • the doped SiO 2 -HuIIe can be applied both by the wet-chemical and by the gas-phase process. However, it is known that with the gas phase method, in principle, a more uniform shell can be applied as with the wet-chemical method.
  • the invention also encompasses doping the dense SiO 2 -HIIs with further doping elements for which calculated energy state densities are not yet present, but whose calculation can be carried out simply as set out below. All doping elements which generate the energy states according to the invention in the doped SiO 2 shell and have not yet been found by chemical experiments are encompassed by this invention.
  • Known doping elements not covered by the invention are Al, B, Ge, Mg, Nb, P, Zr for the - dry gas phase method and Ag, Al, B 1 Ba, Be, Ca, Cd, Co 1 Cr, Cu, Mg, Mn, Ni, Nb , Sn, Sr, Ti, Zn 1 Zr for the wet-chemical process.
  • suitable combinations of two and more doping elements can be determined by calculating the total energy state densities that are due to interaction of the
  • FIG. 1 shows the energy states during the transition from the atom to the solid (taken from: P.A. Cox: "The Electronic Structure and Chemistry of Solids", Oxford Science
  • FIG. 2 shows the energy state density of the TiO 2 surface without and with SiO 2 .
  • FIG. 3 shows the energy state density of the TiO 2 surface with SiO 2 coating and with
  • FIG. 4 shows the energy state density of the TiO 2 surface with SiO 2 coating and with Sb-doped SiO 2 coating.
  • Figure 5 shows the energy state density of the TiO 2 surface with SiO 2 coating and with
  • FIG. 6 shows the energy state density of the TiO 2 surface with SiO 2 coating and with
  • FIG. 7 shows the energy state density of the TiO 2 surface with SiO 2 coating and with
  • FIG. 8 shows the energy state density of the TiO 2 surface with SiO 2 coating and with
  • FIG. 9 shows the energy state density of the TiO 2 surface with SiO 2 coating and with F-doped SiO 2 coating.
  • FIG. 10 shows the energy state density of the TiO 2 surface with SiO 2 coating and with
  • FIG. 11 shows the energy state density of the TiO 2 surface with SiO 2 coating and with
  • Figure 12 shows the energy state density of the TiO 2 surface with SiO 2 coating and with
  • Figure 13 shows the energy state density of the TiO 2 surface with SiO 2 coating and with Cd-doped SiO 2 coating.
  • FIG. 14 shows the energy state density of the TiO 2 surface with SiO 2 coating and Ce-doped SiO 2 coating.
  • FIG. 15 shows the energy state density of the TiO 2 surface with SiO 2 coating and with W doped SiO 2 coating.
  • FIG. 16 shows the energy state density of the TiO 2 surface with SiO 2 coating and with Bi-doped SiO 2 coating.
  • FIG. 17 shows the energy state density of the TiO 2 surface with SiO 2 coating and with Mg-doped SiO 2 coating.
  • FIG. 18 shows the energy state density of the TiO 2 surface with SiO 2 coating and with Al-doped SiO 2 coating.
  • the energy state densities were quantum mechanically calculated using the software package CASTEP (Version 4.6, June 1, 2001) of the manufacturer Accelrys Inc., San Diego.
  • CASTEP Software Package
  • valence states including the semi-core states were used: 3s, 3p, 3d, 4s and 4p.
  • oxygen the valence states were 2s and 2p and for silicon the
  • the semi-core states 4d and 4s and 4p and 2p were included for indium, yttrium and magnesium.
  • the basic set used for the doping elements was as follows:
  • Sn 5s, 5p, 6s, 6p, 7s
  • Sb 5s, 5p, 6s, 6p, 7s
  • Nb 4s, 4p, 4d, 5s, 5p F: 2s, 2p
  • the kinetic energy cutoff for the plane waves was 380 eV.
  • Geometry optimization was not performed because the computational model could be evaluated and confirmed by known experimental results (coating with Sn, Al, Zr and Zn). The model calculations thus provide sufficient accuracy for the study of photostability.
  • a grid was used according to the Monkhorst-Pack scheme. The calculations of the surfaces were carried out according to the "slab model method" with a vacuum thickness of 10 ⁇ .
  • the invention is based on Examples 1 to 14 (doping of the SiO 2 layer with one of the doping elements Sn, Sb, In, Ge, Y, Nb, F, Mn, Cu, Mo, Cd, Ce, W and Bi) and Comparative Example 1 (pure SiO 2 layer), Comparative Example 2 (doping of the SiO 2 layer with Mg) and Comparative Example 3 (doping of the SiO 2 layer with Al) are explained.
  • Comparative Example 1 is based on the complete coverage of a TiO 2 - (1 10) surface with a monolayer SiO 2 .
  • the unit cell comprises 52 atoms (Ti 8 Si 8 O 36 ). Transferred to the pigment corresponds to the calculated monomolecular coverage with SiO 2 at a layer thickness of about 0.2 nm, a weight fraction of about 0.3 wt .-% SiO 2 based on TiO 2 .
  • the weight fraction was calculated on the basis of the following values: typical value of the specific surface area (according to BET) for TiO 2 particles produced by the chloride method: 6.2 m 2 / g, thickness of the monomolecular layer: 0.2 nm, density of SiO 2 Layer: 2.2 g / cm 3 .
  • Examples 1 to 14 and Comparative Examples 2 and 3 describe the covering of the TiO 2 surface with a monomolecular layer SiO 2 which has been doped in the atomic ratio 1 (doping element X): 7 (Si), ie the unit cell comprises Ti 8 Si 7 X 1 O 36 . Transferred to the TiO 2 pigment, the following proportions by weight of the doping elements calculated as oxide and based on TiO 2 result : Example 1: about 0.10 wt.% SnO 2 ,
  • Example 2 about 0.09 wt.% Sb 2 O 3 ,
  • Example 3 about 0.09 wt.% In 2 O 3 ,
  • Example 4 about 0.07 wt.% GeO 2
  • example 5 about 0.14 wt.% Y 2 O 3 ,
  • Example 6 about 0.09 wt.% Nb 2 O 5 ,
  • Example 7 about 0.01% by weight of F
  • Example 8 about 0.06 wt.% MnO 2 ,
  • Example 9 about 0.06 wt% CuO
  • Example 10 about 0.10 wt% MoO 3
  • Example 11 about 0.09 wt .-% CdO 1
  • Example 12 about 0.12 wt.% CeO 2 ,
  • Example 13 about 0.16% by weight of WO 3 ,
  • Example 14 about 0.09 wt.% Bi 2 O 3
  • Comparative Example 2 about 0.03 wt.% MgO
  • Comparative Example 3 about 0.04 wt.% Al 2 O 3
  • FIG. 1 shows a simplified block diagram representation (d) for the electronic structure. The block diagram represents only the energy bandwidth and position of the
  • FIG. 2 shows the effect of a pure, undoped SiO 2 coating (Comparative Example 1) on the photoactivity of the TiO 2 : the calculated density of states of the pure TiO 2 (HO) surface is shown in dashed lines, and that of the SiO 2 -coated surface is shown as solid ,
  • the positive effect of the SiO 2 coating on photostability is firstly due to the lowering of the density of states in the conduction band (CB) near the band gap compared to the uncoated TiO 2 surface, which reduces the transfer of electron-hole pairs to the surrounding matrix ,
  • the positive effect is reinforced by the fact that in addition a reduction in the density of states in the valence band near the band gap (VB) takes place.
  • FIG. 1 shows the effect of a pure, undoped SiO 2 coating (Comparative Example 1) on the photoactivity of the TiO 2 : the calculated density of states of the pure TiO 2 (HO) surface is shown in dashed lines, and that of the SiO 2 -coated surface
  • FIGS. 4 to 8 show the respective effect of doping the SiO 2 layer with Sb (Example 2, FIG. 4), In (Example 3, FIG. 5), Ge (Example 4, FIG. 6), Y (Example 5, Fig. 7) or Nb (Example 6, Fig. 8).
  • Sb Example 2, FIG. 4
  • In Example 3, FIG. 5
  • Ge Example 4, FIG. 6
  • Y Example 5, Fig. 7
  • Nb Example 6, Fig. 8
  • FIGS. 9 to 16 show the respective effect of doping the SiO 2 layer with F (Example 7, FIG. 9), with Mn (Example 8, FIG. 10), with Cu (Example 9, FIG. 11), with Mo (Example 10, FIG. 12), with Cd (Example 11, FIG. 13), with Ce (Example 12, FIG. 14), with W (Example 13, FIG. 15 or with Bi (Example 14, FIG.
  • a method of coating the titanium dioxide particles with a dense SiO 2 as such are known.
  • the traditional procedures lead through the aqueous phase.
  • a Ti0 2 particle suspension is prepared, optionally mixed with a dispersant and optionally wet-ground.
  • the precipitation of the dense SiO 2 -HuIIe is usually carried out by addition of alkali metal silicate solutions and appropriate pH-value management.
  • the doping element is added in the form of a salt solution together with the silicate solution or separately before or after the addition of the silicate solution.
  • the person skilled in the art is aware of the appropriate compounds and amounts needed to control the pH to produce a dense shell.
  • the doping of the dense SiO 2 -HuIIe according to the invention can be achieved for example by adding the following salts in the suspension, this compilation is not to be understood as limiting the invention.
  • germanium chloride germanates
  • Nb doping niobium chloride, niobate
  • an outer layer of alumina hydrate is additionally applied to the particles by known methods.
  • the dense SiO 2 -HuIIe is deposited from the gas phase on the particle surface.
  • various methods are known.
  • the coating can be carried out in a fluidized bed at temperatures below about 1000 ° C. Such methods are described in US 3,552,995, GB 1,330,157 or US 2001 0041217 A1.
  • the coating takes place in the tubular reactor directly after the TiO 2 particle formation in the chloride process; these processes are described, for example, in patents or patent applications WO 98/036441 A1, EP 0 767 759 B1, EP 1042 408 B1 and WO 01/081410 A2.
  • a silicon halide in particular SiCl 4
  • SiCl 4 is usually used as the precursor compound for the SiO 2 , which is generally introduced downstream of the point of combining the reactants TiCl 4 and AICI 3 with the oxygen-containing gas.
  • WO 01/081410 A2 states that the silicon halide is supplied at a location where the TiO 2 formation reaction is at least 97% complete.
  • the temperatures during the introduction should be above 1000 ° C., preferably above 1200 ° C.
  • the SiO 2 precursor compound is oxidized and precipitates as a dense silica shell on the surface of the TiO 2 particles.
  • the wet-chemical process management are in the
  • Gas phase treatment produces water- and hydrate-free oxide layers, which adsorb hydroxyl ions and water molecules only at the surface.
  • the dopant element is also added as a precursor compound, either in parallel with the SiO 2 precursor compound or upstream or downstream, into the particle stream. Again, the temperature of the particle stream at the point of initiation at more than 1000 0 C, preferably above 1200 ° C must be.
  • Suitable precursor compounds for the various doping elements are the following compounds, without this combination being understood as limiting the invention: doping with Sn: tin halide such as stannous chloride doping with Sb: antimony halide such as antimony chloride doping with In: indium halide such as indium chloride doping with Y: yttrium halide Yttrium chloride doping with Zr: zirconium halide such as zirconium chloride doping with Zn: zinc halide such as zinc chloride doping with Nb: niobium halide such as niobium chloride
  • an outer layer of alumina is additionally applied to the particles by introducing further downstream a suitable alumina precursor compound such as AICI 3 into the particle stream.
  • the titanium dioxide pigments provided with the doped dense SiO 2 -HiIIe can be worked up further by known methods. For example, further inorganic layers of one or more metal oxides can be applied. In addition, a further surface treatment with nitrate and / or an organic surface treatment can take place.
  • the compounds known to the person skilled in the art for the organic surface treatment of titanium dioxide pigment particles are also suitable for the organic surface treatment of the particles according to the invention, for example organosilanes, organosiloxanes, organo-phosphonates etc. or polyalcohols such as trimethylethane (TME) or trimethylpropane (TMP). etc.
  • the titanium dioxide pigment particles according to the invention are suitable for use in plastics, paints, varnishes and papers. They can also be used as a starting point for a suspension for the production of, for example, paper or coatings.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Pigments, Carbon Blacks, Or Wood Stains (AREA)
  • Inorganic Compounds Of Heavy Metals (AREA)
  • Cosmetics (AREA)
  • Paper (AREA)

Abstract

Particules pigmentaires de dioxyde de titane à photostabilité améliorée, dont la surface est couverte d'un enrobage de SiO2 dense dopé à l'aide d'au moins un élément de dopage. Ledit enrobage SiO2 est caractérisé en ce que les densités de niveaux permis dans la bande de valence et / ou dans la bande de conduction sont abaissées à proximité de la bande interdite par le dopage à l'aide de l'élément de dopage, ou alors des niveaux d'énergie supplémentaires sont produits dans la bande interdite. Ledit enrobage SiO2 dense dopé est appliqué selon des procédés chimiques par voie humide connus ou en phase gazeuse sur la surface des particules de dioxyde de titane. Les éléments de dopage particulièrement appropriés sont Sn, Sb, In, Ge, Y, Nb, F, Mn, Cu, Mo, Cd, Ce, W et Bi. Sont exclus de la présente invention les éléments de dopage connus suivants : AI, B, Ge, Mg, Nb, P, Zr pour le procédé en phase gazeuse et Ag, AI, B, Ba, Be, Ca, Cd, Co, Cr, Cu, Mg, Mn, Ni, Nb, Sn, Sr, Ti, Zn, Zr pour le procédé chimique par voie humide.
EP07703117A 2006-01-30 2007-01-30 PARTICULES PIGMENTAIRES DE DIOXYDE DE TITANE POURVUES D'UN ENROBAGE DE SiO2 DOPÉ ET DENSE ET PROCÉDÉ DE FABRICATION DE CES PARTICULES Withdrawn EP1979421A2 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE102006004345 2006-01-30
DE102006054988 2006-11-22
PCT/EP2007/000762 WO2007085493A2 (fr) 2006-01-30 2007-01-30 PARTICULES PIGMENTAIRES DE DIOXYDE DE TITANE POURVUES D'UN ENROBAGE DE SiO2 DOPÉ ET DENSE ET PROCÉDÉ DE FABRICATION DE CES PARTICULES

Publications (1)

Publication Number Publication Date
EP1979421A2 true EP1979421A2 (fr) 2008-10-15

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US (1) US7988780B2 (fr)
EP (1) EP1979421A2 (fr)
JP (1) JP5135231B2 (fr)
KR (1) KR101340904B1 (fr)
AU (1) AU2007209489B2 (fr)
BR (1) BRPI0707322A2 (fr)
MY (2) MY153667A (fr)
RU (1) RU2487150C2 (fr)
UA (1) UA95622C2 (fr)
WO (1) WO2007085493A2 (fr)

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KR101830780B1 (ko) 2011-08-05 2018-04-05 삼성전자주식회사 박막의 제조방법, 박막, 박막의 제조장치 및 전자소자
FI125473B (en) * 2012-11-28 2015-10-15 Sachtleben Pigments Oy Titanium dioxide pigment
JP2015059291A (ja) * 2013-09-20 2015-03-30 王子ホールディングス株式会社 化粧板原紙
RU2555484C2 (ru) * 2013-10-08 2015-07-10 Федеральное государственное бюджетное образовательное учреждение высшего профессионального образования "Томский государственный университет систем управления и радиоэлектроники" Пигмент на основе порошка диоксида титана, модифицированного наночастицами
KR20190045165A (ko) * 2016-08-29 2019-05-02 신에쓰 가가꾸 고교 가부시끼가이샤 코팅 조성물 및 피복 물품
CN108165052B (zh) * 2017-12-14 2020-11-24 华南理工大学 一种具有近红外反射功能的陶瓷色料及其制备方法
CN108033486B (zh) * 2017-12-15 2019-11-05 河北麦森钛白粉有限公司 一种导电介孔纳米二氧化钛的制备方法
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AU2007209489B2 (en) 2011-09-22
UA95622C2 (uk) 2011-08-25
BRPI0707322A2 (pt) 2011-05-03
MY164937A (en) 2018-02-15
WO2007085493A2 (fr) 2007-08-02
KR20080090472A (ko) 2008-10-08
JP5135231B2 (ja) 2013-02-06
AU2007209489A1 (en) 2007-08-02
RU2487150C2 (ru) 2013-07-10
US7988780B2 (en) 2011-08-02
RU2008135142A (ru) 2010-03-10
KR101340904B1 (ko) 2013-12-13
US20100282128A1 (en) 2010-11-11
MY153667A (en) 2015-03-13
JP2009525368A (ja) 2009-07-09
WO2007085493A3 (fr) 2007-09-13

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