WO1996036441A1 - ENROBAGE DE PIGMENT DE TiO2 PAR REACTIONS EN PHASE GAZEUSE ET DE SURFACE - Google Patents

ENROBAGE DE PIGMENT DE TiO2 PAR REACTIONS EN PHASE GAZEUSE ET DE SURFACE Download PDF

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Publication number
WO1996036441A1
WO1996036441A1 PCT/US1996/007886 US9607886W WO9636441A1 WO 1996036441 A1 WO1996036441 A1 WO 1996036441A1 US 9607886 W US9607886 W US 9607886W WO 9636441 A1 WO9636441 A1 WO 9636441A1
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Prior art keywords
metal
reactor
coating
precursor
group
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Application number
PCT/US1996/007886
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English (en)
Inventor
Toivo Kodas
Quint Powell
Bruce Anderson
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Kemira Pigments, Inc.
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Application filed by Kemira Pigments, Inc. filed Critical Kemira Pigments, Inc.
Priority to AU62501/96A priority Critical patent/AU6250196A/en
Publication of WO1996036441A1 publication Critical patent/WO1996036441A1/fr

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    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
    • C23C16/22—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the deposition of inorganic material, other than metallic material
    • C23C16/30—Deposition of compounds, mixtures or solid solutions, e.g. borides, carbides, nitrides
    • C23C16/40—Oxides
    • C23C16/401—Oxides containing silicon
    • C23C16/402—Silicon dioxide
    • 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
    • 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
    • C09C1/3669—Treatment with low-molecular organic compounds
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
    • C23C16/22—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the deposition of inorganic material, other than metallic material
    • C23C16/30—Deposition of compounds, mixtures or solid solutions, e.g. borides, carbides, nitrides
    • C23C16/40—Oxides
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
    • C23C16/22—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the deposition of inorganic material, other than metallic material
    • C23C16/30—Deposition of compounds, mixtures or solid solutions, e.g. borides, carbides, nitrides
    • C23C16/40—Oxides
    • C23C16/403—Oxides of aluminium, magnesium or beryllium
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
    • C23C16/22—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the deposition of inorganic material, other than metallic material
    • C23C16/30—Deposition of compounds, mixtures or solid solutions, e.g. borides, carbides, nitrides
    • C23C16/40—Oxides
    • C23C16/405—Oxides of refractory metals or yttrium
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
    • C23C16/44—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of 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
    • 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
    • C01P2002/00—Crystal-structural characteristics
    • C01P2002/70—Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/01—Particle morphology depicted by an image
    • C01P2004/04—Particle morphology depicted by an image obtained by TEM, STEM, STM or AFM
    • 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
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2006/00—Physical properties of inorganic compounds
    • C01P2006/19—Oil-absorption capacity, e.g. DBP values

Definitions

  • This invention pertains to a process of coating titanium dioxide particles with metal oxides by gas-phase reaction.
  • the gas-phase reaction of TiCl 4 and 0 2 is used to make particulate Ti0 2 often of a size useful as a white pigment.
  • the pigment particles are usually not used in typical applications such as paint without first coating them with materials including, but not limited to, Si0 2 , A1 2 0 3 and mixtures thereof. To coat the particles, they are typically collected from the gas and dispersed in a liquid where the coating is applied by precipitation. This liquid-phase coating process often results in coatings with high surfaces areas, high oil absorption, and non-uniform thickness.
  • U.S. Patent 4,803,056 describes a method for increasing the capacity of a titanium dioxide producing process. Titanium tetrachloride is added at a second point in the system downstream of the main inlet for titanium tetrachloride to increase the yield of Ti0 2 . The process is exclusively used for the production of uncoated titanium dioxide. The addition of other reagents at the second point of introduction in order to produce a coating on the Ti0 2 particles is not suggested or disclosed.
  • Huncr and Katz disclose a process for forming coated particles in a flame.
  • non-pigmentary Ti0 2 can be coated with Si0 2 in a flame reactor whereby TiCl 4 and SiCl 4 are added simultaneously into the same flame.
  • the reaction conditions must be carefully adjusted such that Ti0 2 condenses before Si0 2 in order to achieve a coating of Si0 2 on the already formed Ti0 2 particles. It is difficult to reliably produce Si0 2 -coated Ti0 2 particles of a uniform quality in terms of size and coating hardness with this process.
  • the process for making pigment-grade Ti0 2 coated with a metal oxide according to the present invention is primarily characterized by the following steps: introducing a thermally decomposable volatile titanium-containing precursor into a reactor; thermally decomposing the titanium- containing precursor within the reactor to form Ti0 2 pigment particles; subsequently injecting at least one thermally decomposable volatile metal-containing coating precursor into the reactor; and reacting the at least one metal- containing coating precursor within the reactor to form a coating of at least one metal oxide on the Ti0 2 pigment particles.
  • the coating is selected from the group consisting of Si0 2 , Al 2 0 3 , Zr0 2 , and mixed metal oxide.
  • the titanium-containing precursor is selected from the group consisting of TiCl 4 , TiBr 4 , and Ti(OR) 4 , wherein R is an alkyl group.
  • the method advantageously further comprises the step of adding a thermally decomposable volatile aluminum-containing precursor to the titanium-containing precursor to form Al-doped Ti0 2 .
  • a thermally decomposable volatile aluminum-containing precursor to the titanium-containing precursor to form Al-doped Ti0 2 .
  • water may also be added to control the particle size of the formed Ti0 2 pigment particles.
  • the metal-containing coating precursor is selected from the group consisting of SiX 4 , A1X 3 , and ZrX 4 , wherein X is Cl, Br or OR, R being an alkyl group.
  • X is Cl, Br or OR, R being an alkyl group.
  • other metal-containing coating precursors can be used equally successfully.
  • metal alkyls metal alkenyls, metal alkynes, metal allyls, metallocenes, metal cyclopentadienes, metal arenes, metal alkoxides, and metal ⁇ -diketonates, all well known to a person skilled in the art. It is also possible to use metal carbonyls, metal oxyhalides, and metal hydrides.
  • the method further comprises the step of adding a co-reactant, preferably water, to the metal-containing coating precursor.
  • a co-reactant preferably water
  • water may be used to modify or control the reaction of the coating precursor.
  • the reactor is advantageously a tubular flow reactor.
  • the method further comprises the step of selecting a location for an injection element for injecting the at least one metal-containing coating precursor downstream of a Ti0 2 -formation zone of the tubular flow reactor.
  • the injection element is selected from the group consisting of a slot, a porous wall element, an annular segment of a coaxial tube of the tubular flow reactor, and a radially extending injection port.
  • At least two of the metal-containing coating precursors are injected at a single point through an injection element selected from the group consisting of a slot and a porous wall segment.
  • the inventive method according to another embodiment further comprises the step of selecting a plurality of locations for injection elements for injecting at least two of the metal- containing coating precursors downstream of a Ti0 2 -formation zone of the tubular flow reactor.
  • the coating precursors may be injected as mixtures, or separately but simultaneously at the same point in the reactor, or may be injected separately at different points in the reactor to produce mixed oxide coatings or to produce a coating comprising separate layers of metal oxides.
  • the injection elements are selected from the group consisting of a slot, a porous wall element, an annular segment of coaxial tube of the tubular flow reactor, and a radially extending injection port.
  • each separate coating layer has a thickness of 1-100 nm.
  • the coating has a total thickness of 1-100 nm.
  • the step of thermally decomposing includes the step of heating by fuel combustion, by conduction or by a plasma arc for initiating the formation of Ti0 2 .
  • the step of introducing the titanium- coating precursor includes the step of selecting a first and a second location of introduction, wherein the second location is arranged downstream of the first location.
  • the step of introducing the titanium- containing precursor and/or the step of injecting the metal-containing coating precursor may include the step of employing a carrier gas, for example, oxygen.
  • the method further comprises the step of collecting the Ti0 2 pigment particles downstream of the flow reactor.
  • the reactor is maintained at atmospheric pressure during the inventive process. It is also possible to maintain less than atmospheric pressure (vacuum) within the reactor or perform the inventive process at a pressure of 1 to 10 atm (atmospheres) within the reactor.
  • the present invention describes a gas- phase method for making coated pigment grade Ti0 2 . It allows multi-component coatings and multilayer coatings.
  • the coatings produced by the inventive process are dense and have low oil absorption. The inventive process eliminates the need to collect the particles before the coating can be applied thereby simplifying the manufacturing process.
  • Ti0 2 pigment particles are produced by a gas-phase reaction of titanium-containing precursors, for example, TiX 4 , suspended in a gas stream and are then coated with a coating of metal oxide(s) produced by gas-phase and surface reactions of thermally decomposable volatile metal atom- or ion-containing coating reactants introduced at a single point or multiple points into a tubular flow system at a location downstream of the formation zone in which the Ti0 2 pigment particles are fully formed.
  • titanium-containing precursors for example, TiX 4
  • the inventive system or apparatus consists of three sections including sequentially: a tubular flow formation zone in which the Ti0 2 particles are formed, a zone in which the thermally decomposable volatile metal atom- or ion-containing coating reactants (precursors) are introduced into the gas stream carrying the Ti0 2 particles to be coated, and a coating zone in which the Ti0 2 particles are coated by the metal oxide(s) being formed from the metal-containing coating precursor(s) .
  • the titanium dioxide particles are formed by gas-phase reaction.
  • the volatile metal-containing coating precursors are injected which react in the gas phase as well as on the surface of the titanium dioxide particles to form a coating.
  • the coated particles are then collected at the exit of the flow reactor.
  • the inventive system consists of the following components: a pigment particle generator (particle formation zone) , an introduction zone for the thermally decomposable volatile metal- containing coating precursor (reactant) , and a coating zone.
  • a pigment particle generator particle formation zone
  • an introduction zone for the thermally decomposable volatile metal- containing coating precursor reactant
  • a coating zone In the particle formation zone, TiCl 4 reacts with 0 2 to form respective Ti0 2 particles (illustrated as small circles) .
  • the drawing shows the introduction of three thermally decomposable volatile metal-containing coating reactants downstream of the particle formation zone: ML n , M'L n , and M''L n where M, M' , M' ' represent a metal atom and L represents a ligand attached to the metal atom. However, the reaction of only one coating reactant ML n is shown.
  • reaction to form the metal oxide can take place in the gas phase (formation of small particles, illustrated by small cross-hatched circles) which are then captured by the preformed Ti0 2 particles to form the coating or can take place at the surface of the Ti0 2 particles resulting in a direct coating of the Ti0 2 particle (the produced coating is schematically represented by cross-hatching) .
  • Preferred compounds are, for example,
  • organic ligands such as metal alkyls, metal alkenyls, metal alkynes, metal allyls, metallocenes, metal cyclopentadienes, metal arenes, metal alkoxides, and metal ⁇ - diketonates
  • inorganic ligands such as metal carbonyls, metal oxyhalides, and metal hydrides.
  • the given compounds are examples only and not meant to limit the scope of the inventive process
  • the drawing shows the sequential nature of the process in which the particles are formed first, followed by introduction of the thermally decomposable volatile metal-containing coating reactants, and then coating. It is also obvious that only one or a plurality of thermally decomposable volatile metal-containing coating reactants can be used, as desired and needed for the Ti0 2 pigment product properties. Thus, the invention is not limited with respect to the number of thermally decomposable volatile metal- containing coating reactants that can be used, the order in which they are introduced into the reactor, or the type of thermally decomposable volatile metal-containing coating reactant.
  • TiCl 4 as a titanium precursor can be mixed with A1C1 3 , introduced into the reactor with oxygen (carrier gas) at a temperature of about 900 °C or higher, and reacted in a tubular flow system to give Ti0 2 particles containing Al.
  • oxygen carrier gas
  • water can be added, as is well known in the art, in order to help adjust or control the Ti0 2 particle size.
  • the gist of the present invention is the addition (injection) of a thermally decomposable volatile metal-containing coating reactant into a reactor tube at a location downstream of the zone in which the Ti0 2 particles are formed, but where the temperature is still high enough to cause reaction of the thermally decomposable volatile metal-containing coating reactants both in the gas phase and on the surfaces of the Ti0 2 pigment particles.
  • thermally decomposable volatile metal-containing coating reactants it is also possible to add two thermally decomposable volatile metal-containing coating reactants at the same time to give a single coating which is a mixed oxide of the two metals.
  • SiX 4 and A1X 3 can be added together resulting in a mixed oxide [Si0 2 ] x [Al 2 0 3 ] y wherein essentially any ratio between the two oxides is possible.
  • two or more thermally decomposable volatile metal-containing coating reactants are added sequentially to give a coating comprised of two or more layers of individual metal oxides.
  • the invention can be carried out in a variety of apparatus configurations.
  • the preferred embodiment is a tubular flow system in which the thermally decomposable volatile metal- containing coating reactants are introduced from the exterior of the reactor tube into the reactor tube at points downstream of the zone in which the Ti0 2 particles are formed but where the temperature is still high enough to cause reaction of the thermally decomposable volatile metal- containing coating reactants both in the gas phase and on the surfaces of the particles.
  • Various approaches can be used to introduce the thermally decomposable volatile metal-containing coating reactants into the reactor.
  • the thermally decomposable volatile metal-containing coating reactants can be 10 added through a porous wall or through radially extending injection points. It is also possible to use coaxial injection.
  • the temperature at which the thermally decomposable volatile metal-containing coating reactants are to be decomposed must be sufficiently high in order for the coating reactants to react at the surface of the Ti0 2 20 particles or for the particles of the coating material, formed in the gas phase, to be able to collide with the Ti0 2 pigment particles and fuse into their surfaces. Temperatures that are too low result in formation of separate particles 25 comprised of the coating material that are not incorporated into the coating. Temperatures that are too high result in reaction of the coating
  • the temperature For the coating of Ti0 2 with Si0 2 using SiCl 4 , the temperature must be greater than 1300°C. When Ti0 2 is to be coated with Al 2 0 3 , the temperature must be greater than 1100°C. For coating Ti0 2 with a mixed Si/Al oxide, the temperature must be greater than 1200°C. However, in any case, the temperature must not be too high in order to prevent interdiffusion and/or reaction between Ti0 2 and the coating material.
  • the flow reactor can be heated to the required reaction temperature by conventional methods such as fuel combustion, conduction, a plasma arc or other means well known to a person skilled in the art.
  • the energy derived from the exothermic reaction of the Ti-containing precursor with oxygen for heating the flow reactor to the desired reaction temperature when the gaseous reactants (Ti- containing precursor and oxygen) are preheated to a suitable preheating temperature.
  • the exothermicity of the reaction aids in reaching the required temperature in all possible process variations.
  • the inventive process can be carried out under various pressures.
  • the reactor can simply be maintained at atmospheric pressure during the inventive process. It is also possible to maintain less than atmospheric pressure (vacuum) within the reactor or perform the inventive process at a pressure of 1 to 10 atm (atmospheres) within the reactor.
  • Example 1 Formation of Ti0 2 particles coated with SiO,
  • a tubular flow reactor was used at a temperature of 1500 °C.
  • Oxygen gas carrier gas
  • the resulting gas mixture was then introduced into a reactor tube with a residence time of less than 10 seconds.
  • the gas mixture reacted to form Ti0 2 particles in the reactor.
  • Liquid SiCl 4 was vaporized by heating at
  • the surface reaction resulted in the direct deposition of a uniform continuous coating with a thickness of 10 nm as shown by Transmission Electron Microscopy.
  • the composition of the coating was confirmed by energy dispersive spectroscopy which showed only Si and O. X-ray diffraction showed only Ti0 2 and confirmed that the coating process did not degrade the properties of the pigment by forming additional undesired phases.
  • Example 2 Formation of Ti0 2 particles coated with A1 2 0 3 .
  • a tubular flow reactor was used at a temperature of 1500 °C.
  • Oxygen (carrier gas) was guided through TiCl 4 to vaporize and introduce TiCl 4 into the carrier gas.
  • the resulting gas mixture was then introduced into a reactor tube with a residence time of less than 10 sec. The gas mixture reacted to form Ti0 2 particles in the reactor.
  • A1C1 3 was vaporized by heating at less than 250 °C and passing a carrier gas over the powder. The vapor was introduced into the hot region of the reactor using tubes inserted from the exit of the reactor. This allowed A1C1 3 to be introduced into the reactor in a region where the temperature was near 1500°C. A1C1 3 reacted both in the gas phase and on the surfaces of the formed Ti0 2 particles. The gas phase reaction of the metal-containing coating precursor A1C1 3 resulted in the formation of small particles of Al 2 0 3 which were captured by the Ti0 2 particles and incorporated into the surface as a coating by sintering. Because of the small size of the Al 2 0 3 particles, sintering was rapid.
  • the particles were collected on a filter after exiting the reactor.
  • the surface reaction resulted in the direct deposition of a uniform continuous coating with a thickness of 10 nm as shown by Transmission Electron Microscopy.
  • the composition of the coating was confirmed by energy dispersive spectroscopy which showed only Al and 0. X-ray diffraction showed only Ti0 2 and confirmed that the coating process did not degrade the properties of the Ti0 2 pigment particles by forming additional undesired phases.
  • a tubular flow reactor was used at a temperature of 1500 °C.
  • Oxygen carrier gas
  • TiCl 4 was guided through TiCl 4 to vaporize and introduce TiCl 4 into the carrier gas.
  • the resulting gas mixture was then introduced into a reactor tube with a residence time of less than 10 sec. The gas mixture reacted to form Ti0 2 particles in the reactor.
  • SiCl 4 was vaporized by heating at 25°C without a carrier gas, and A1C1 3 was vaporized by heating at less than 250°C with carrier gas flowing over the AlCl 3 powder.
  • the streams were combined and introduced as a vapor into the hot region of the reactor using tubes inserted from the exit of the reactor. This allowed the SiCl 4 and A1C1 3 to be introduced into the reactor in a region where the temperature was near 1500°C.
  • SiCl 4 and A1C1 3 reacted both in the gas phase and on the surfaces of the particles.
  • the gas phase reaction resulted in the formation of small metal oxide particles which were captured by the formed Ti0 2 particles and incorporated into the surface as a coating by sintering.
  • the coated Ti0 2 pigment particles were collected onto a filter after exiting the reactor.
  • the surface reaction resulted in the direct deposition of a uniform continuous coating with a thickness of 10 nm as shown by Transmission Electron Microscopy.
  • the composition of the coating was confirmed by energy dispersive spectroscopy which showed only Si, Al and 0. X- ray diffraction showed only Ti0 2 and confirmed that the coating process did not degrade the properties of the pigment by forming additional undesired phases.

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  • Organic Chemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
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  • Metallurgy (AREA)
  • Inorganic Chemistry (AREA)
  • Inorganic Compounds Of Heavy Metals (AREA)

Abstract

Dans un procédé de production de TiO2 de qualité pigmentaire enrobé d'un oxyde de métal, on introduit dans un réacteur un précurseur contenant du titane volatile thermodécomposable. Le précurseur contenant du titane est thermodécomposé à l'intérieur du réacteur afin de former des particules de pigment de TiO2. Ensuite, on injecte dans le réacteur un ou plusieurs précurseurs d'enrobage volatiles thermodécomposables contenant un métal. On fait réagir le ou les précurseurs contenant du métal à l'intérieur du réacteur afin de former un enrobage d'un ou de plusieurs oxydes de métal sur les particules de pigment de TiO2.
PCT/US1996/007886 1995-05-17 1996-05-17 ENROBAGE DE PIGMENT DE TiO2 PAR REACTIONS EN PHASE GAZEUSE ET DE SURFACE WO1996036441A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU62501/96A AU6250196A (en) 1995-05-17 1996-05-17 Coating of tio2 pigment by gas-phase and surface reactions

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US44305595A 1995-05-17 1995-05-17
US08/443,055 1995-05-17

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WO1996036441A1 true WO1996036441A1 (fr) 1996-11-21

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Cited By (19)

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US5728205A (en) * 1996-12-11 1998-03-17 E. I. Du Pont De Nemours And Company Process for the addition of boron in a TiO2 manufacturing process
EP0908494A2 (fr) * 1997-10-08 1999-04-14 E.I. Dupont De Nemours And Company Oxyde métallique uniformément revêtu
WO1999032562A1 (fr) * 1997-12-23 1999-07-01 E.I. Du Pont De Nemours And Company PROCEDE DE PRODUCTION D'UN PIGMENT ENROBE DE TiO2 PAR COOXYDATION POUR L'OBTENTION DE REVETEMENTS A BASE D'OXYDE AQUEUX
DE19824440C1 (de) * 1998-05-30 1999-09-02 Karlsruhe Forschzent Verfahren zur Herstellung eines goldhaltigen Pigments
WO2000020516A1 (fr) * 1998-10-02 2000-04-13 Sri International Processus a sec pour enrobage de particules d'anhydride de titane
WO2001081480A3 (fr) * 2000-04-27 2002-02-28 Du Pont Procede de realisation de pigment de dioxyde de titane durable dans le procede au chlore sans utilisation de traitement humide
US6416721B1 (en) * 1998-10-02 2002-07-09 Sri International Fluidized bed reactor having a centrally positioned internal heat source
DE10260718A1 (de) * 2002-12-23 2004-07-08 Degussa Ag Mit Siliziumdioxid umhülltes Titandioxid
WO2005113442A1 (fr) * 2004-05-21 2005-12-01 Degussa Ag Poudre ternaire a base d'oxydes metalliques mixtes
EP1785395A1 (fr) 2005-11-12 2007-05-16 Degussa GmbH Procédé de préparation de particules d'oxyde métallique dopé
DE102005002846A1 (de) * 2005-01-20 2007-05-16 Seoul Nat Univ Ind Foundation Vorrichtung und Verfahren zum Herstellen von beschichtetem Nanopartikelverbund
WO2007085493A2 (fr) * 2006-01-30 2007-08-02 Kronos International, Inc. PARTICULES PIGMENTAIRES DE DIOXYDE DE TITANE POURVUES D'UN ENROBAGE DE SiO2 DOPÉ ET DENSE ET PROCÉDÉ DE FABRICATION DE CES PARTICULES
WO2008019905A1 (fr) * 2006-08-17 2008-02-21 Evonik Degussa Gmbh Particules d'oxyde de zinc enrobées de silice pouvant être obtenues par un procédé de pyrolyse à flamme
WO2009027433A2 (fr) * 2007-08-28 2009-03-05 Basf Se Fabrication de particules de dioxyde de titane revêtues de sio2, à revêtement réglable
US7763110B2 (en) 2006-01-30 2010-07-27 Kronos International Inc Titanium dioxide pigment particles with doped, dense SiO2 skin and methods for their manufacture
EP2209618A1 (fr) * 2007-11-16 2010-07-28 Millennium Inorganic Chemicals, Inc. Production de phase gazeuse de dioxyde de titane revêtu
EP2222794A2 (fr) * 2007-12-05 2010-09-01 M. Kamal Akhtar Procédé de fabrication de pigments à base de dioxyde de titane enduit
US7905953B2 (en) 2006-01-30 2011-03-15 Kronos International Inc Titanium dioxide pigment particles with doped, dense SiO2 skin and methods for their manufacture
CN103298744A (zh) * 2011-01-10 2013-09-11 纳幕尔杜邦公司 二氧化钛制备中控制粒度和添加剂覆盖率的方法

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US4050951A (en) * 1974-12-20 1977-09-27 Societa' Italiana Resine S.I.R. S.P.A. Process for the post-treatment of titanium dioxide pigments

Cited By (39)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5728205A (en) * 1996-12-11 1998-03-17 E. I. Du Pont De Nemours And Company Process for the addition of boron in a TiO2 manufacturing process
EP0908494A2 (fr) * 1997-10-08 1999-04-14 E.I. Dupont De Nemours And Company Oxyde métallique uniformément revêtu
EP0908494A3 (fr) * 1997-10-08 1999-11-10 E.I. Dupont De Nemours And Company Oxyde métallique uniformément revêtu
US6086668A (en) * 1997-10-08 2000-07-11 E. I. Du Pont De Nemours And Company Uniformly coated particulate metal oxide
AU750442B2 (en) * 1997-12-23 2002-07-18 E.I. Du Pont De Nemours And Company Process for producing coated TiO2 pigment using cooxidation to provide hydrous oxide coatings
WO1999032562A1 (fr) * 1997-12-23 1999-07-01 E.I. Du Pont De Nemours And Company PROCEDE DE PRODUCTION D'UN PIGMENT ENROBE DE TiO2 PAR COOXYDATION POUR L'OBTENTION DE REVETEMENTS A BASE D'OXYDE AQUEUX
US5922120A (en) * 1997-12-23 1999-07-13 E. I. Du Pont De Nemours And Company Process for producing coated TiO2 pigment using cooxidation to provide hydrous oxide coatings
DE19824440C1 (de) * 1998-05-30 1999-09-02 Karlsruhe Forschzent Verfahren zur Herstellung eines goldhaltigen Pigments
WO2000020516A1 (fr) * 1998-10-02 2000-04-13 Sri International Processus a sec pour enrobage de particules d'anhydride de titane
US6416721B1 (en) * 1998-10-02 2002-07-09 Sri International Fluidized bed reactor having a centrally positioned internal heat source
WO2001081480A3 (fr) * 2000-04-27 2002-02-28 Du Pont Procede de realisation de pigment de dioxyde de titane durable dans le procede au chlore sans utilisation de traitement humide
US6852306B2 (en) * 2000-04-27 2005-02-08 E. I. Du Pont De Nemours And Company Process for making durable rutile titanium dioxide pigment by vapor phase deposition of surface treatments
US7029648B2 (en) 2000-04-27 2006-04-18 E. I. Du Pont De Nemours And Company Process for making durable rutile titanium dioxide pigment by vapor phase deposition of surface treatment
DE10260718A1 (de) * 2002-12-23 2004-07-08 Degussa Ag Mit Siliziumdioxid umhülltes Titandioxid
WO2004056927A2 (fr) 2002-12-23 2004-07-08 Degussa Ag Dioxyde de titane recouvert de silice
US7244302B2 (en) 2002-12-23 2007-07-17 Degussa Ag Titanium dioxide coated with silicon dioxide
WO2005113442A1 (fr) * 2004-05-21 2005-12-01 Degussa Ag Poudre ternaire a base d'oxydes metalliques mixtes
DE102005002846B4 (de) * 2005-01-20 2015-07-23 Seoul National University Industry Foundation Vorrichtung und Verfahren zum Herstellen von beschichtetem Nanopartikelverbund
DE102005002846A1 (de) * 2005-01-20 2007-05-16 Seoul Nat Univ Ind Foundation Vorrichtung und Verfahren zum Herstellen von beschichtetem Nanopartikelverbund
WO2007054412A1 (fr) * 2005-11-12 2007-05-18 Evonik Degussa Gmbh Procédé pour la production de particules d'oxyde de métal dopées
EP1785395A1 (fr) 2005-11-12 2007-05-16 Degussa GmbH Procédé de préparation de particules d'oxyde métallique dopé
US8535633B2 (en) 2005-11-12 2013-09-17 Evonik Degussa Gmbh Process for the production of doped metal oxide particles
US7905953B2 (en) 2006-01-30 2011-03-15 Kronos International Inc Titanium dioxide pigment particles with doped, dense SiO2 skin and methods for their manufacture
WO2007085493A3 (fr) * 2006-01-30 2007-09-13 Kronos Int Inc PARTICULES PIGMENTAIRES DE DIOXYDE DE TITANE POURVUES D'UN ENROBAGE DE SiO2 DOPÉ ET DENSE ET PROCÉDÉ DE FABRICATION DE CES PARTICULES
JP2009525368A (ja) * 2006-01-30 2009-07-09 クローノス インターナショナル インコーポレイテッド ドープされた緻密なＳｉＯ２皮膜を備えた二酸化チタン顔料粒子及びその製造方法
US7763110B2 (en) 2006-01-30 2010-07-27 Kronos International Inc Titanium dioxide pigment particles with doped, dense SiO2 skin and methods for their manufacture
WO2007085493A2 (fr) * 2006-01-30 2007-08-02 Kronos International, Inc. PARTICULES PIGMENTAIRES DE DIOXYDE DE TITANE POURVUES D'UN ENROBAGE DE SiO2 DOPÉ ET DENSE ET PROCÉDÉ DE FABRICATION DE CES PARTICULES
WO2008019905A1 (fr) * 2006-08-17 2008-02-21 Evonik Degussa Gmbh Particules d'oxyde de zinc enrobées de silice pouvant être obtenues par un procédé de pyrolyse à flamme
JP2009545509A (ja) * 2006-08-17 2009-12-24 エボニック デグサ ゲーエムベーハー 火炎熱分解法により得られたシリカ被覆酸化亜鉛粒子
WO2009027433A2 (fr) * 2007-08-28 2009-03-05 Basf Se Fabrication de particules de dioxyde de titane revêtues de sio2, à revêtement réglable
WO2009027433A3 (fr) * 2007-08-28 2009-05-14 Basf Se Fabrication de particules de dioxyde de titane revêtues de sio2, à revêtement réglable
EP2209618A1 (fr) * 2007-11-16 2010-07-28 Millennium Inorganic Chemicals, Inc. Production de phase gazeuse de dioxyde de titane revêtu
EP2209618A4 (fr) * 2007-11-16 2014-01-22 Cristal Usa Inc Production de phase gazeuse de dioxyde de titane revêtu
US8663380B2 (en) 2007-11-16 2014-03-04 Cristal Usa Inc. Gas phase production of coated titania
EP2222794A4 (fr) * 2007-12-05 2010-12-01 Akhtar M Kamal Procédé de fabrication de pigments à base de dioxyde de titane enduit
EP2222794A2 (fr) * 2007-12-05 2010-09-01 M. Kamal Akhtar Procédé de fabrication de pigments à base de dioxyde de titane enduit
CN103298744A (zh) * 2011-01-10 2013-09-11 纳幕尔杜邦公司 二氧化钛制备中控制粒度和添加剂覆盖率的方法
CN103298744B (zh) * 2011-01-10 2015-07-29 纳幕尔杜邦公司 二氧化钛制备中控制粒度和添加剂覆盖率的方法
US9416277B2 (en) 2011-01-10 2016-08-16 The Chemours Company Tt, Llc Process for controlling particle size and additive coverage in the preparation of titanium dioxide

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