WO1998053010A1 - Metal oxide coated titanium dioxide lamellas - Google Patents

Metal oxide coated titanium dioxide lamellas Download PDF

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Publication number
WO1998053010A1
WO1998053010A1 PCT/EP1997/002650 EP9702650W WO9853010A1 WO 1998053010 A1 WO1998053010 A1 WO 1998053010A1 EP 9702650 W EP9702650 W EP 9702650W WO 9853010 A1 WO9853010 A1 WO 9853010A1
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WO
WIPO (PCT)
Prior art keywords
titanium dioxide
metal oxide
pigment
pigments
drying
Prior art date
Application number
PCT/EP1997/002650
Other languages
German (de)
French (fr)
Inventor
Stephanie Andes
Gerd Bauer
Günter BRENNER
Dieter BRÜCKNER
Michael Schmelz
Andrea Heyland
Matthias Kuntz
Karl Osterried
Gerhard Pfaff
Original Assignee
Merck Patent Gmbh
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
Priority to DE19618568A priority Critical patent/DE19618568A1/en
Application filed by Merck Patent Gmbh filed Critical Merck Patent Gmbh
Priority to EP97923992A priority patent/EP0931112B1/en
Priority to DE59709110T priority patent/DE59709110D1/en
Priority to JP10549831A priority patent/JP2000515927A/en
Priority to BR9710754-9A priority patent/BR9710754A/en
Priority to US09/230,261 priority patent/US6238472B1/en
Priority to PCT/EP1997/002650 priority patent/WO1998053010A1/en
Publication of WO1998053010A1 publication Critical patent/WO1998053010A1/en

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    • 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
    • C09C1/0015—Pigments exhibiting interference colours, e.g. transparent platelets of appropriate thinness or flaky substrates, e.g. mica, bearing appropriate thin transparent coatings
    • C09C1/0018—Pigments exhibiting interference colours, e.g. transparent platelets of appropriate thinness or flaky substrates, e.g. mica, bearing appropriate thin transparent coatings uncoated and unlayered plate-like particles
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K8/00—Cosmetics or similar toiletry preparations
    • A61K8/18—Cosmetics or similar toiletry preparations characterised by the composition
    • A61K8/19—Cosmetics or similar toiletry preparations characterised by the composition containing inorganic ingredients
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K8/00—Cosmetics or similar toiletry preparations
    • A61K8/18—Cosmetics or similar toiletry preparations characterised by the composition
    • A61K8/19—Cosmetics or similar toiletry preparations characterised by the composition containing inorganic ingredients
    • A61K8/29—Titanium; Compounds thereof
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61Q—SPECIFIC USE OF COSMETICS OR SIMILAR TOILETRY PREPARATIONS
    • A61Q17/00—Barrier preparations; Preparations brought into direct contact with the skin for affording protection against external influences, e.g. sunlight, X-rays or other harmful rays, corrosive materials, bacteria or insect stings
    • A61Q17/04—Topical preparations for affording protection against sunlight or other radiation; Topical sun tanning preparations
    • 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
    • C08K9/00—Use of pretreated ingredients
    • C08K9/02—Ingredients treated with inorganic substances
    • 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
    • C09C1/0015—Pigments exhibiting interference colours, e.g. transparent platelets of appropriate thinness or flaky substrates, e.g. mica, bearing appropriate thin transparent coatings
    • 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
    • C09C1/0015—Pigments exhibiting interference colours, e.g. transparent platelets of appropriate thinness or flaky substrates, e.g. mica, bearing appropriate thin transparent coatings
    • C09C1/0021—Pigments exhibiting interference colours, e.g. transparent platelets of appropriate thinness or flaky substrates, e.g. mica, bearing appropriate thin transparent coatings comprising a core coated with only one layer having a high or low refractive index
    • 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
    • C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
    • C09D5/36—Pearl essence, e.g. coatings containing platelet-like pigments for pearl lustre
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K2800/00—Properties of cosmetic compositions or active ingredients thereof or formulation aids used therein and process related aspects
    • A61K2800/40—Chemical, physico-chemical or functional or structural properties of particular ingredients
    • A61K2800/42—Colour properties
    • A61K2800/43—Pigments; Dyes
    • 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
    • C09C2200/00—Compositional and structural details of pigments exhibiting interference colours
    • C09C2200/10—Interference pigments characterized by the core material
    • C09C2200/1004—Interference pigments characterized by the core material the core comprising at least one inorganic oxide, e.g. Al2O3, TiO2 or SiO2
    • 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
    • C09C2200/00—Compositional and structural details of pigments exhibiting interference colours
    • C09C2200/30—Interference pigments characterised by the thickness of the core or layers thereon or by the total thickness of the final pigment particle
    • C09C2200/301—Thickness of the core
    • 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
    • C09C2200/00—Compositional and structural details of pigments exhibiting interference colours
    • C09C2200/30—Interference pigments characterised by the thickness of the core or layers thereon or by the total thickness of the final pigment particle
    • C09C2200/302—Thickness of a layer with high refractive material
    • 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
    • C09C2200/00—Compositional and structural details of pigments exhibiting interference colours
    • C09C2200/30—Interference pigments characterised by the thickness of the core or layers thereon or by the total thickness of the final pigment particle
    • C09C2200/303—Thickness of a layer with low refractive material
    • 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
    • C09C2200/00—Compositional and structural details of pigments exhibiting interference colours
    • C09C2200/30—Interference pigments characterised by the thickness of the core or layers thereon or by the total thickness of the final pigment particle
    • C09C2200/306—Thickness of an absorbing layer
    • 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
    • C09C2200/00—Compositional and structural details of pigments exhibiting interference colours
    • C09C2200/30—Interference pigments characterised by the thickness of the core or layers thereon or by the total thickness of the final pigment particle
    • C09C2200/308—Total thickness of the pigment particle
    • 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
    • C09C2220/00—Methods of preparing the interference pigments
    • C09C2220/10—Wet methods, e.g. co-precipitation
    • 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
    • C09C2220/00—Methods of preparing the interference pigments
    • C09C2220/10—Wet methods, e.g. co-precipitation
    • C09C2220/106—Wet methods, e.g. co-precipitation comprising only a drying or calcination step of the finally coated pigment

Definitions

  • the invention relates to very thin pearlescent pigments based on platelet-shaped titanium dioxide coated with metal oxide or coated with metal oxide hydrate.
  • Pearlescent pigments based on Giimmer which have further metal oxide layers on a titanium dioxide layer
  • Aluminum oxide, zirconium oxide, zinc oxide and tin oxide are mentioned as colorless oxides for a second metal oxide layer
  • iron oxide, nickel oxide, cobalt oxide, copper oxide and chromium oxide are mentioned as oxides which have their own color.
  • the deposition of a second metal oxide on the titanium dioxide hydrate layer leads to a clear stabilization with regard to the light sensitivity of this layer.
  • Titanium dioxide pigments containing iron oxide in particular have been used successfully for many years.
  • US Pat. No. 3,874,890 describes a process for the production of gold-colored pearlescent pigments, in which a mica pigment coated with Ti0 2 and / or Zr0 2 is first coated with iron (II) hydroxide, which is then oxidized to Fe 2 0 3 .
  • US 4744832 describes a pearlescent pigment based on platelet-shaped substrates coated with metal oxides, in particular mica, the metal oxide layer containing both titanium and iron and the pigment having a multilayer structure, with a first
  • Layer of Ti0 2 in the rutile form is followed by a layer of pseudobrookite and an iron oxide layer.
  • Mica pigments are widely used in the printing and coatings industry, in cosmetics and in plastics processing. They are characterized by interference colors and a high gloss.
  • mica pigments are not suitable for the formation of extremely thin layers because mica as a substrate for the metal oxide layers of the pigment already has a thickness of 200 to 1200 nm.
  • a further disadvantage is that the thickness of the mica platelets fluctuates significantly around an average value within a certain fraction, which is determined by the platelet size.
  • mica is a naturally occurring mineral that is contaminated by foreign ions. Furthermore, technically very complex and time-consuming preparation steps are necessary. Above all, this includes grinding and classifying.
  • Pearlescent pigments based on thick mica platelets and coated with metal oxides have a clear scattering component due to the thickness of the edge, especially with finer grain size distributions below 20 ⁇ m.
  • Thin glass plates which are obtained by rolling a glass melt with subsequent grinding, have been proposed as a replacement for mica.
  • Interference pigments based on such materials have color effects which are superior to those of conventional mica-based pigments.
  • the glass flakes have a very large average thickness of approximately 10-15 ⁇ m and a very wide distribution of thicknesses (typically between 4 and 20 ⁇ m), while the thickness of interference pigments is typically not greater than 3 ⁇ m.
  • EP 0,384,596 describes a process in which hydrated alkali silicate is subjected to an air jet at temperatures of 480-500 ° C., whereby bubbles with thin walls form; the bubbles are then crushed and you get platelet-shaped
  • DE 11 36 042 describes a continuous belt process for the production of platelet-like or flake-like oxides or oxide hydrates of metals of the IV and V groups and of the iron group of the periodic table. In this case, if necessary, a separating layer of, for example, silicone varnish is first applied to a continuous belt in order to later detach the
  • EP 0.240.952 and EP 0.236.952 have proposed a continuous belt process for the production of various platelet-shaped materials, including silicon dioxide, aluminum oxide and titanium dioxide.
  • a thin liquid film of a defined thickness of a precursor of the platelet-shaped material is applied to a smooth belt using a roller system; the film is dried and peeled off the tape, forming platelet-shaped particles. The particles are then optionally annealed, ground and classified.
  • the thickness of the platelets obtained by the process described in EP 0 240 952 is relatively well defined, since the film is applied very uniformly, for example, to the continuous belt using a roller system.
  • the layer thickness of the platelets is given in the examples as 0.3 to 3.0 ⁇ m.
  • a first roll is wetted with the precursor used by partially immersing this roll in a storage container filled with the precursor.
  • the film is transferred from this reel to a second reel rotating in the same direction, which is in very close contact with the first.
  • the film is unwound from the second roll onto the continuous belt.
  • the use of very expensive precursor materials and, in particular, the increased demands on job security that have to be made when using organometallic compounds are disadvantageous.
  • the complete chemical conversion of the precursor into the desired layer material generally requires a strong heating of the film and the strip material. In addition to the considerable thermal load on the strip material, the high energy consumption and the limitation of the process speed have a very disadvantageous effect on the economy of the process.
  • WO 93/08 237 describes platelet-shaped pigments, consisting of a platelet-shaped matrix of silicon dioxide, which can contain soluble or insoluble colorants and which is coated with one or more reflective layers of metal oxides or metals.
  • the platelet-shaped matrix is produced by solidifying water glass on an endless belt.
  • DE 1 273 098 describes the production of a mother-of-pearl pigment by vapor deposition of ZnS, MgF2, ZnO, CaF2 and TiO2 films on an endless belt.
  • this process like the process described in US Pat. No. 4,879,140, in which platelet-shaped pigments with Si and SiO 2 layers are obtained by plasma deposition from SiH4 and SiCl4, is associated with a very high outlay on equipment.
  • the object of the invention is to provide high-gloss titanium dioxide-containing pearlescent pigments with a layer thickness of less than 500 nm and a layer thickness tolerance of less than 10%.
  • This object is achieved according to the invention by a pearlescent pigment with a multilayer structure, a layer of another metal oxide or metal oxide hydrate being followed by a core of platelet-shaped titanium dioxide, obtainable by solidifying an aqueous solution of a thermally hydrolyzable titanium compound on an endless belt, detaching the resulting layer, coating of the titanium dioxide platelets obtained without intermediate drying in the wet process with another metal oxide, separation, drying and optionally calcining the material obtained.
  • the other metal oxide or metal oxide hydrate that is applied to the titanium dioxide is Fe 2 0 3 , Fe 3 0 4 , FeOOH, Cr 2 0 3 , CuO, Ce 2 0 3) Al 2 0 3 , Si0 2 , B.VO 4 , NiTi0 3 , CoTi0 3 and antimony-doped, fluorine-doped or indium-doped tin oxide.
  • a third layer of a further metal oxide or metal oxide hydrate is present on the second layer made of another metal oxide or metal oxide hydrate.
  • This further metal oxide or metal oxide hydrate is aluminum oxide or aluminum oxide hydrate, silicon dioxide or silicon dioxide hydrate, Fe 2 0 3 , Fe 3 ⁇ 4 , FeOOH, Zr0 2l Cr 2 0 3 and antimony-doped, fluorine-doped or indium-doped tin oxide.
  • the aqueous solution of a thermally hydrolyzable titanium compound for the production of the titanium dioxide flakes on the endless belt is preferably an aqueous titanium tetrachloride solution.
  • the concentration of the titanium salt in these solutions is 7 to 30% by weight, preferably 8 to 15% by weight.
  • this object is achieved according to the invention by a method for producing the pigments according to the invention by an aqueous solution of a thermally hydrolyzable titanium compound is applied as a thin film to an endless belt,
  • the liquid film is solidified by drying and the titanium dioxide is developed from the precursor by a chemical reaction
  • the resulting layer is then removed from the belt and washed
  • the titanium dioxide platelets obtained are suspended in water after or without intermediate drying and are coated with another metal oxide and optionally with further metal oxides,
  • coated titanium dioxide platelets are separated from the aqueous suspension, dried and optionally calcined.
  • the coating of the titanium dioxide platelets with metal oxides or metal oxide hydrates can also be e.g. in a fluidized bed reactor by gas phase coating, e.g. the methods proposed in EP 0.045.851 and EP 0.106.235 for the production of pearlescent pigments can be used accordingly.
  • the invention also relates to the use of the pigments according to the invention for pigmenting lacquers, printing inks, plastics, cosmetics and glazes for ceramics and glasses.
  • the pigments according to the invention are based on platelet-shaped titanium dioxide. These platelets have a thickness between 10 nm and 500 nm, preferably between 40 and 150 nm. The extent in the other two dimensions is between 2 and 200 ⁇ m and in particular between 5 and 50 ⁇ m.
  • the layer of another metal oxide which is applied to the titanium dioxide platelets has a thickness of 5 to 300 nm, preferably between 5 and 150 nm.
  • the pigments according to the invention are produced in a three-stage process.
  • platelet-shaped titanium dioxide particles are produced using an endless belt.
  • Roller applicators and flowers can be used as suitable applicators.
  • the belt speed is between 2 and 400 m / min, preferably 5-200 m / min.
  • the coated strip then runs through a drying section 4 in which the layer is dried at temperatures between 30 and 200 ° C.
  • a drying section 4 in which the layer is dried at temperatures between 30 and 200 ° C.
  • commercially available infrared, circulating air and UV dryers can be used as dryers.
  • the tape is passed through the release baths 5 with a suitable release medium, for example deionized water, where the dried layer is removed from the tape.
  • a suitable release medium for example deionized water
  • the tape is dried in a post-dryer 6 before it is re-coated.
  • the endless belt should be made of a chemically and thermally resistant plastic to ensure a sufficient service life and high drying temperatures.
  • Materials such as polyethylene terephthalate (PET) or other polyesters and polyacrylates are suitable for this.
  • the film width is typically between a few centimeters up to several meters.
  • the thickness is between 10 ⁇ m and a few mm, whereby these two parameters are optimized with regard to the respective requirements.
  • the titanium dioxide flakes detached from the tape are coated in a second process step without prior drying with another metal oxide by a known method.
  • iron (III) salts can be used as described, for example, in US Pat. No. 3,987,828 and US Pat. No. 3,087,829, and iron (II) - salt, as described in US Pat. No. 3,874,890, the initially formed coating of iron (II) hydroxide being oxidized to the iron (III) oxide hydrate.
  • the preferred starting point is iron (III) salts.
  • an aqueous suspension of the titanium dioxide platelets at a temperature of 60 to 90 ° C and an iron (III) chloride solution is metered in at a pH of 2.5 to 4.5. The pH value is kept constant by simultaneous dosing of 32% sodium hydroxide solution. After working up and drying at 110 ° C., a red pigment is obtained.
  • the coating with magnetite (Fe 3 ⁇ 4 ) is carried out by hydrolysis of an iron (II) salt solution, for example iron (II) sulfate, at a pH of 8.0 in the presence of potassium nitrate.
  • an iron (II) salt solution for example iron (II) sulfate
  • the exact precipitation examples are described in EP 0 659 843.
  • a black pigment is obtained after working up and drying at 100 ° C.
  • a coating of the titanium dioxide platelets with yellow FeO (OH) in the goethite modification is also preferred.
  • An aqueous FeS0 4 solution is metered into a suspension of the titanium dioxide platelets in a nitrogen atmosphere at 70 ° C. Then the pH is adjusted to 4 with a 10% Na 2 CO 3 solution and oxygen is introduced into the suspension. After working up and drying at 110 ° C., a yellow pigment is obtained. With regard to the exact precipitation conditions, reference is made to EP 0 659 843.
  • chromium oxide Another metal oxide that is preferentially struck on the titanium dioxide platelets is chromium oxide.
  • the deposition can easily be effected by the thermal hydrolysis which occurs when ammonia evaporates from an aqueous solution of a hexamine-chromium (III) derivative, or by thermal hydrolysis of a chromium salt solution which is buffered with borax.
  • the coating with chromium oxide is described in US 3087828 and 3,087,829.
  • the pigments according to the invention do not have to be calcined in every case. Drying at temperatures of 110 ° C is sufficient for certain applications. If the pigment is calcined, temperatures between 400 ° C and 1000 ° C are set, the preferred range being between 400 ° C and 700 ° C.
  • the pigment of the invention can additionally be coated with sparingly soluble, firmly adhering inorganic or organic colorants.
  • Colored lacquers and in particular aluminum colored lacquers are preferably used.
  • an aluminum hydroxide layer is struck, which is then varnished with a colored varnish. The process is described in more detail in DE 24 29 762 and DE 29 28 287.
  • An additional coating with complex salt pigments in particular cyanoferrate complexes, such as for example Powell Blau and Turnbulls Blau, as described in EP 0 141 173 and DE 23 13 332, is also preferred.
  • the pigment according to the invention can also be coated with organic dyes and in particular with phthalocyanine or metal phthalocyanine and / or indanthrene dyes according to DE 40 09 567.
  • organic dyes and in particular with phthalocyanine or metal phthalocyanine and / or indanthrene dyes according to DE 40 09 567.
  • a suspension of the pigment is prepared in a solution of the dye and this is then brought together with a solvent in which the dye is sparingly soluble or insoluble.
  • Metal chalcogenides or metal chalcogenide hydrates and carbon black can also be used for an additional coating. It is also possible to subject the pigments to a post-coating or post-treatment which further increases the light, weather and chemical stability, or to facilitate the handling of the pigment, in particular the incorporation into different media.
  • the following layers are, for example, those described in DE-PS 22 15 191, DE-
  • the pigments according to the invention represent the ideal state which can be attained as far as possible with pearlescent pigments, since they consist only of optically functional layers and an otherwise customary carrier material, such as mica or glass plates, which does not contribute to the optical effect, is missing. Due to the thickness of the mica, mica pigments are up to 25 times thicker with the same thickness of the functional layers. With regard to technical applications, this results in intrinsic advantages that no other conventional pearlescent pigment can achieve. For example, lacquer layers can be made thinner and the necessary amount of pigment can be reduced because the pigments are more optically active due to the lack of the “filler” carrier material.
  • a circumferential belt made of polyethylene terephthalate (width: 0.3 m, speed: 20 m / min) is coated with a 20% titanium tetrachloride solution in counter-rotation on an application roller.
  • the coating solution contains 0.3% by weight of surfactant (DISPERSE-AYD W-28, manufacturer: DANIEL PRODUCTS COMPANY).
  • the aqueous film on the belt is dried in a drying section by exposure to hot air at 70 ° C. and the layer formed is detached from the belt in a detachment basin filled with deionized water.
  • the platelet-shaped titanium dioxide particles are filtered and washed with deionized water.
  • the silvery, shiny platelets have a layer thickness of 100 ⁇ 10 nm. To coat them with another metal oxide, they are redispersed in deionized water.
  • the Snd4 solution is added to the TiO 2 suspension at 3 ml / min and the pH 1.8 is kept constant with 32% NaOH solution. After the SnO 2 coating, the suspension is stirred for 15 minutes at constant temperature and pH.
  • the pH is then adjusted to 3.0 with 32% NaOH solution and an aqueous 8% iron (III) chloride solution is metered in at a rate of 3 ml / min, the pH being increased by simultaneous addition of the NaOH Solution is kept constant.
  • the FeCI 3 addition is continued until the desired interference color is reached.
  • the pigment obtained is filtered off, washed with deionized water and dried at 110 ° C. for 12 hours.
  • the pigment has the desired interference color and a red body color.

Abstract

The invention relates to a pearly lustre pigment, consisting of a titanium oxide lamella-shaped core and one or several coatings of different metal oxides or metal oxide hydrates, which can be obtained by hardening an aqueous solution of a titanium compound that can be thermally hydrolyzed on a continuous strip, by separating the layer thus arising, by coating the titanium dioxide lamellas thus obtained with one or several metal oxide or metal oxide hydrates, e.g. Fe2O3, Fe3O4, FeOOH or Cr2O3 after or without intermediate drying in a wet process and by separating, drying and optionally calcinating the material thus obtained.

Description

Metalloxidbeschichtete Titandioxidplättchen Metal oxide coated titanium dioxide platelets
Die Erfindung betrifft sehr dünne Perlglanzpigmente auf der Basis von metalloxidbeschichtetem bzw. metalloxidhydratbeschichtetem plättchen- förmigem Titandioxid.The invention relates to very thin pearlescent pigments based on platelet-shaped titanium dioxide coated with metal oxide or coated with metal oxide hydrate.
Perlglanzpigmente auf Giimmerbasis, die auf einer Titandioxidschicht weitere Metalloxidschichten besitzen, sind bekannt. In US 3087 828 und 3 087 829 werden als farblose Oxide für eine zweite Metalloxidschicht Aluminiumoxid, Zirkoniumoxid, Zinkoxid und Zinnoxid und als Oxide, die eine Eigenfärbung aufweisen, Eisenoxid, Nickeloxid, Kobaltoxid, Kupferoxid und Chromoxid genannt. Die Abscheidung eines zweiten Metalloxides auf der Titandioxihydratschicht führt zu einer deutlichen Stabilisierung bezüglich der Lichtempfindlichkeit dieser Schicht. Insbesondere eisenoxid- haltige Titandioxidpigmente werden seit vielen Jahren mit Erfolg angewendet.Pearlescent pigments based on Giimmer, which have further metal oxide layers on a titanium dioxide layer, are known. In US 3087 828 and 3 087 829 aluminum oxide, zirconium oxide, zinc oxide and tin oxide are mentioned as colorless oxides for a second metal oxide layer and iron oxide, nickel oxide, cobalt oxide, copper oxide and chromium oxide are mentioned as oxides which have their own color. The deposition of a second metal oxide on the titanium dioxide hydrate layer leads to a clear stabilization with regard to the light sensitivity of this layer. Titanium dioxide pigments containing iron oxide in particular have been used successfully for many years.
In US 30 87 828 wird beschrieben, daß durch Abscheiden einer Fe203- Schicht auf eine Ti02-Schicht goldfarbene Glimmerpigmente erhalten wer- den, die beim Glühen einen rötlichen Farbton annehmen.In US 30 87 828 it is described that by depositing an Fe 2 0 3 layer on a TiO 2 layer, gold-colored mica pigments are obtained which take on a reddish color when annealed.
In US 3 874890 wird ein Verfahren zur Herstellung von goldfarbenen Perlglanzpigmenten beschrieben, bei dem ein mit Ti02 und/oder Zr02 beschichtetes Glimmerpigment zunächst mit Eisen(ll)-hydroxid beschichtet wird, das dann zu Fe203 oxidiert wird.US Pat. No. 3,874,890 describes a process for the production of gold-colored pearlescent pigments, in which a mica pigment coated with Ti0 2 and / or Zr0 2 is first coated with iron (II) hydroxide, which is then oxidized to Fe 2 0 3 .
US 4744832 beschreibt ein Perlglanzpigment auf Basis von mit Metalloxiden überzogenen plättchenförmigen Substraten, insbesondere Glimmer, wobei die Metalloxidschicht sowohl Titan als auch Eisen enthält und das Pigment einen Mehrschichtaufbau besitzt, wobei auf eine ersteUS 4744832 describes a pearlescent pigment based on platelet-shaped substrates coated with metal oxides, in particular mica, the metal oxide layer containing both titanium and iron and the pigment having a multilayer structure, with a first
Schicht von Ti02 in der Rutilform eine Schicht von Pseudobrookit und eine Eisenoxidschicht folgt. Glimmerpigmente werden in großem Umfang in der Druck- und Lackindustrie, in der Kosmetik und in der Kunststoffverarbeitung verwendet. Sie zeichnen sich durch Interferenzfarben und einen hohen Glanz aus. Für die Ausbildung extrem dünner Schichten sind aber Glimmerpigmente nicht ge- eignet, weil Glimmer als Substrat für die Metalloxidschichten des Pigmentes bereits eine Dicke von 200 bis 1200 nm aufweist. Nachteilig ist weiterhin, daß die Dicke der Glimmerplättchen innerhalb einer bestimmten Fraktion, die durch die Plättchengröße bestimmt wird, teilweise deutlich um einen Mittelwert schwankt. Außerdem handelt es sich bei Glimmer um ein natürlich vorkommendes Mineral, das durch Fremdionen verunreinigt ist. Desweiteren sind technisch sehr aufwendige und zeitraubende Aufbereitungsschritte notwendig. Hierzu zählen vor allem Mahlen und Klassieren.Layer of Ti0 2 in the rutile form is followed by a layer of pseudobrookite and an iron oxide layer. Mica pigments are widely used in the printing and coatings industry, in cosmetics and in plastics processing. They are characterized by interference colors and a high gloss. However, mica pigments are not suitable for the formation of extremely thin layers because mica as a substrate for the metal oxide layers of the pigment already has a thickness of 200 to 1200 nm. A further disadvantage is that the thickness of the mica platelets fluctuates significantly around an average value within a certain fraction, which is determined by the platelet size. In addition, mica is a naturally occurring mineral that is contaminated by foreign ions. Furthermore, technically very complex and time-consuming preparation steps are necessary. Above all, this includes grinding and classifying.
Auf dicken Glimmerplättchen basierende, mit Metalloxiden umhüllte Perl- glanzpigmente haben aufgrund der Dicke des Randes einen deutlichen Streuanteil, speziell bei feineren Korngrößenverteilungen unter 20 μm.Pearlescent pigments based on thick mica platelets and coated with metal oxides have a clear scattering component due to the thickness of the edge, especially with finer grain size distributions below 20 μm.
Als Ersatz für Glimmer sind dünne Glasplättchen vorgeschlagen worden, die durch Walzen einer Glasschmelze mit nachfolgendem Mahlen erhalten werden. Interferenzpigmente auf der Basis derartiger Materialien weisen zwar Farbeffekte auf, die denen herkömmlicher, auf Glimmer basierender Pigmente überlegen sind. Nachteilig ist jedoch, daß die Glasplättchen eine sehr große mittlere Dicke von etwa 10-15 μm und eine sehr breite Dickenverteilung (typischerweise zwischen 4 und 20 μm) aufweisen, während die Dicke von Interferenzpigmenten typischerweise nicht größer als 3 μm ist.Thin glass plates, which are obtained by rolling a glass melt with subsequent grinding, have been proposed as a replacement for mica. Interference pigments based on such materials have color effects which are superior to those of conventional mica-based pigments. However, it is disadvantageous that the glass flakes have a very large average thickness of approximately 10-15 μm and a very wide distribution of thicknesses (typically between 4 and 20 μm), while the thickness of interference pigments is typically not greater than 3 μm.
In EP 0,384,596 wird ein Verfahren beschrieben, bei dem hydratisiertes Alkalisilikat bei Temperaturen von 480-500 °C mit einem Luftstrahl beaufschlagt wird, wobei sich Blasen mit dünnen Wandstärken bilden; die Bla- sen werden anschließend zerkleinert und man erhält plättchenförmigeEP 0,384,596 describes a process in which hydrated alkali silicate is subjected to an air jet at temperatures of 480-500 ° C., whereby bubbles with thin walls form; the bubbles are then crushed and you get platelet-shaped
Alkalisilikatsubstrate mit einer Dicke von weniger als 3 μm. Das Verfahren ist jedoch aufwendig und die Dickenverteilung der erhaltenen Plättchen ist relativ breit. In DE 11 36 042 ist ein kontinuierliches Bandverfahren zur Herstellung plättchen- oder flitterartiger Oxide oder Oxidhydrate von Metallen der IV. und V. Gruppe sowie der Eisen-Gruppe des Periodensystems beschrieben. Dabei wird auf ein kontinuierliches Band ggf. zunächst eine Trenn- schicht aus z.B. Silikonlack aufgebracht, um das spätere Ablösen derAlkaline silicate substrates with a thickness of less than 3 μm. However, the process is complex and the thickness distribution of the platelets obtained is relatively broad. DE 11 36 042 describes a continuous belt process for the production of platelet-like or flake-like oxides or oxide hydrates of metals of the IV and V groups and of the iron group of the periodic table. In this case, if necessary, a separating layer of, for example, silicone varnish is first applied to a continuous belt in order to later detach the
Metalloxidschicht zu erleichtern. Anschließend wird ein Flüssigkeitsfilm aus einer Lösung einer hydrolysierbaren Verbindung des in das gewünschte Oxid umzuwandelnden Metalls aufgebracht, der Film wird getrocknet und anschließend mit einer Rüttelvorrichtung abgelöst. Die Schichtdicke der erhaltenen Plättchen wird mit 0,2 bis 2 μm angegeben, ohne hierfür konkrete Beispiele zu nennen.Lighten metal oxide layer. Then a liquid film is applied from a solution of a hydrolyzable compound of the metal to be converted into the desired oxide, the film is dried and then detached with a vibrating device. The layer thickness of the platelets obtained is given as 0.2 to 2 μm, without giving specific examples.
In EP 0,240,952 und EP 0,236,952 ist ein kontinuierliches Bandverfahren zur Herstellung verschiedener plättchenförmiger Materialien, darunter auch Siliciumdioxid, Aluminiumoxid und Titandioxid vorgeschlagen worden. Dabei wird über ein Roliensystem auf ein glattes Band ein dünner flüssiger Film definierter Dickes eines Precursors des plättchenförmigen Materials aufgebracht; der Film wird getrocknet und von dem Band abgelöst, wobei sich plättchenförmige Teilchen bilden. Die Teilchen werden anschließend gegebenenfalls geglüht, gemahlen und klassiert.EP 0.240.952 and EP 0.236.952 have proposed a continuous belt process for the production of various platelet-shaped materials, including silicon dioxide, aluminum oxide and titanium dioxide. A thin liquid film of a defined thickness of a precursor of the platelet-shaped material is applied to a smooth belt using a roller system; the film is dried and peeled off the tape, forming platelet-shaped particles. The particles are then optionally annealed, ground and classified.
Die Dicke der nach dem in EP 0 240 952 beschriebenen Verfahren erhaltenen Plättchen ist relativ gut definiert, da der Film z.B. auf das kontinuierliche Band über ein Rollensystem sehr gleichmäßig aufgebracht wird. Die Schichtdicke der Plättchen wird in den Beispielen mit 0,3 bis 3,0 μm angegeben. Gemäß Beispiel 1 wird eine erste Rolle mit dem verwendeten Pre- cursor benetzt, indem man diese Rolle teilweise in einen mit dem Precur- sor befüllten Vorratsbehälter eintaucht. Der Film wird von dieser Rolle auf eine zweite, gleichsinnig rotierende Rolle übertragen, die mit der ersten in sehr engem Kontakt steht. Schließlich wird der Film von der zweiten Rolle auf das kontinuierliche Band abgerollt. Nachteilig sind jedoch die Verwendung sehr teurer Precursormaterialien sowie insbesondere die erhöhten Anforderungen an die Arbeitsplatzsicherheit, die beim Einsatz metallorganischer Verbindungen gestellt werden müssen. Die vollständige chemische Umwandlung des Precursors in das gewünschte Schichtmaterial macht in der Regel eine starke Erhitzung des Filmes und des Bandmaterials erforderlich. Neben der dabei auftretenden erheblichen thermischen Belastung des Bandmaterials, wirken sich auch der hohe Energieaufwand und die Einschränkung der Prozeßgeschwindigkeit sehr nachteilig auf die Wirtschaftlichkeit des Verfahrens aus.The thickness of the platelets obtained by the process described in EP 0 240 952 is relatively well defined, since the film is applied very uniformly, for example, to the continuous belt using a roller system. The layer thickness of the platelets is given in the examples as 0.3 to 3.0 μm. According to Example 1, a first roll is wetted with the precursor used by partially immersing this roll in a storage container filled with the precursor. The film is transferred from this reel to a second reel rotating in the same direction, which is in very close contact with the first. Finally, the film is unwound from the second roll onto the continuous belt. However, the use of very expensive precursor materials and, in particular, the increased demands on job security that have to be made when using organometallic compounds are disadvantageous. The complete chemical conversion of the precursor into the desired layer material generally requires a strong heating of the film and the strip material. In addition to the considerable thermal load on the strip material, the high energy consumption and the limitation of the process speed have a very disadvantageous effect on the economy of the process.
WO 93/08 237 beschreibt plättchenförmige Pigmente, bestehend aus einer plättchenförmigen Matrix aus Siliciumdioxid, die lösliche oder nichtlösliche Farbmittel enthalten kann und die mit einer oder mehreren reflek- tierenden Schichten aus Metalloxiden oder Metallen belegt ist. Die plättchenförmige Matrix wird durch Verfestigung von Wasserglas auf einem endlosen Band hergestellt.WO 93/08 237 describes platelet-shaped pigments, consisting of a platelet-shaped matrix of silicon dioxide, which can contain soluble or insoluble colorants and which is coated with one or more reflective layers of metal oxides or metals. The platelet-shaped matrix is produced by solidifying water glass on an endless belt.
In DE 1 273 098 wird die Herstellung eines Perlmuttpigmentes durch Auf- dampfen von ZnS-, MgF2-, ZnO-, CaF2- und Tiθ2-Filmen auf ein endloses Band beschrieben. Dieses Verfahren ist aber ebenso, wie das in US 4 879 140 beschriebene Verfahren, bei dem plättchenförmige Pigmente mit Si- und Siθ2-Schichten durch Plasmaabscheidung aus SiH4 und SiCl4 erhalten werden, mit einem sehr hohen apparativen Aufwand verbunden.DE 1 273 098 describes the production of a mother-of-pearl pigment by vapor deposition of ZnS, MgF2, ZnO, CaF2 and TiO2 films on an endless belt. However, this process, like the process described in US Pat. No. 4,879,140, in which platelet-shaped pigments with Si and SiO 2 layers are obtained by plasma deposition from SiH4 and SiCl4, is associated with a very high outlay on equipment.
Trotz zahlreicher Versuche konnte bisher noch kein wirtschaftliches Verfahren zur Herstellung sehr dünner plättchenförmiger Titandioxidpigmente mit einer Schichtdicke von kleiner als 500 nm entwickelt werden.Despite numerous attempts, it has not yet been possible to develop an economical process for the production of very thin platelet-shaped titanium dioxide pigments with a layer thickness of less than 500 nm.
Aufgabe der Erfindung ist es, hochglänzende titandioxidhaltige Perlglanzpigmente mit einer Schichtdicke von kleiner als 500 nm und einer Schichtdickentoleranz von weniger als 10 % bereitzustellen. Diese Aufgabe wird gemäß der Erfindung gelöst durch ein Perlglanzpigment mit einem Mehrschichtaufbau, wobei auf einen Kern aus plättchen- förmigem Titandioxid eine Schicht aus einem anderen Metalloxid oder Metalloxidhydrat folgt, erhältlich durch Verfestigung einer wäßrigen Lösung einer thermisch hydrolysierbaren Titanverbindung auf einem endlosen Band, Ablösung der entstandenen Schicht, Beschichtung der erhaltenen Titandioxidplättchen ohne Zwischentrocknung im Naßverfahren mit einem anderen Metalloxid, Abtrennung, Trocknung und gegebenenfalls Kalzination des erhaltenen Materials.The object of the invention is to provide high-gloss titanium dioxide-containing pearlescent pigments with a layer thickness of less than 500 nm and a layer thickness tolerance of less than 10%. This object is achieved according to the invention by a pearlescent pigment with a multilayer structure, a layer of another metal oxide or metal oxide hydrate being followed by a core of platelet-shaped titanium dioxide, obtainable by solidifying an aqueous solution of a thermally hydrolyzable titanium compound on an endless belt, detaching the resulting layer, coating of the titanium dioxide platelets obtained without intermediate drying in the wet process with another metal oxide, separation, drying and optionally calcining the material obtained.
Das andere Metalloxid oder Metalloxidhydrat, das auf das Titandioxid aufgebracht wird, ist Fe203, Fe304, FeOOH, Cr203, CuO, Ce203) Al203, Si02, B.VO4, NiTi03, CoTi03 sowie antimondotiertes, fluordotiertes oder indiumdotiertes Zinnoxid.The other metal oxide or metal oxide hydrate that is applied to the titanium dioxide is Fe 2 0 3 , Fe 3 0 4 , FeOOH, Cr 2 0 3 , CuO, Ce 2 0 3) Al 2 0 3 , Si0 2 , B.VO 4 , NiTi0 3 , CoTi0 3 and antimony-doped, fluorine-doped or indium-doped tin oxide.
In einer besonderen Ausführungsform des erfindungsgemäßen Pigmentes ist auf der 2. Schicht aus einem anderen Metalloxid oder Metalloxidhydrat noch eine 3. Schicht aus einem weiteren Metalloxid oder Metalloxidhydrat vorhanden. Dieses weitere Metalloxid oder Metalioxidhydrat ist Alumini- umoxid oder Aluminiumoxidhydrat, Siliziumdioxid oder Siliziumdioxidhydrat, Fe203, Fe3θ4, FeOOH, Zr02l Cr203 sowie antimondotiertes, fluordotiertes oder indiumdotiertes Zinnoxid.In a special embodiment of the pigment according to the invention, a third layer of a further metal oxide or metal oxide hydrate is present on the second layer made of another metal oxide or metal oxide hydrate. This further metal oxide or metal oxide hydrate is aluminum oxide or aluminum oxide hydrate, silicon dioxide or silicon dioxide hydrate, Fe 2 0 3 , Fe 3 θ 4 , FeOOH, Zr0 2l Cr 2 0 3 and antimony-doped, fluorine-doped or indium-doped tin oxide.
Die wäßrige Lösung einer thermisch hydrolysierbaren Titanverbindung für die Herstellung der Titandioxidplättchen auf dem endlosen Band ist bevorzugt eine wäßrige Titantetrachloridlösung.The aqueous solution of a thermally hydrolyzable titanium compound for the production of the titanium dioxide flakes on the endless belt is preferably an aqueous titanium tetrachloride solution.
Die Konzentration des Titansalzes in diesen Lösungen beträgt 7 bis 30 Gew.-%, vorzugsweise 8 bis 15 Gew.-%.The concentration of the titanium salt in these solutions is 7 to 30% by weight, preferably 8 to 15% by weight.
Weiterhin wird diese Aufgabe gemäß der Erfindung gelöst durch ein Verfahren zur Herstellung der erfindungsgemäßen Pigmente, indem eine wäßrige Lösung einer thermisch hydrolysierbaren Titanverbindung als dünner Film auf ein endloses Band aufgebracht wird,Furthermore, this object is achieved according to the invention by a method for producing the pigments according to the invention by an aqueous solution of a thermally hydrolyzable titanium compound is applied as a thin film to an endless belt,
der flüssige Film durch Trocknung verfestigt wird und dabei das Titandioxid durch eine chemische Reaktion aus dem Precursor entwickelt wird,the liquid film is solidified by drying and the titanium dioxide is developed from the precursor by a chemical reaction,
die entstandene Schicht anschließend vom Band abgelöst und gewaschen wird,the resulting layer is then removed from the belt and washed,
die erhaltenen Titandioxidplättchen nach oder ohne Zwischentrocknung in Wasser suspendiert und mit einem anderen Metalloxid und gegebenenfalls mit weiteren Metalloxiden beschichtet werden,the titanium dioxide platelets obtained are suspended in water after or without intermediate drying and are coated with another metal oxide and optionally with further metal oxides,
- die beschichteten Titandioxidplättchen aus der wäßrigen Suspension abgetrennt, getrocknet und gegebenenfalls kalziniert werden.- The coated titanium dioxide platelets are separated from the aqueous suspension, dried and optionally calcined.
Weiterhin kann die Beschichtung der Titandioxidplättchen nach Zwischentrocknung mit Metalloxiden bzw. Metalloxidhydraten auch z.B. in einem Wirbelbettreaktor durch Gasphasenbeschichtung erfolgen, wobei z.B. die in EP 0,045,851 und EP 0,106,235 zur Herstellung von Perlglanzpigmenten vorgeschlagenen Verfahren entsprechend angewendet werden können.After intermediate drying, the coating of the titanium dioxide platelets with metal oxides or metal oxide hydrates can also be e.g. in a fluidized bed reactor by gas phase coating, e.g. the methods proposed in EP 0.045.851 and EP 0.106.235 for the production of pearlescent pigments can be used accordingly.
Gegenstand der Erfindung ist außerdem die Verwendung der erfindungsgemäßen Pigmente zur Pigmentierung von Lacken, Druckfarben, Kunststoffen, Kosmetika und Glasuren für Keramiken und Gläser.The invention also relates to the use of the pigments according to the invention for pigmenting lacquers, printing inks, plastics, cosmetics and glazes for ceramics and glasses.
Hierfür können sich auch als Mischungen mit handelsüblichen Pigmenten, beispielsweise anorganischen und organischen Absorptionspigmenten, Metalleffektpigmenten und LCP-Pigmenten, eingesetzt werden. Die erfindungsgemäßen Pigmente basieren auf plättchenförmigem Titandioxid. Diese Plättchen haben eine Dicke zwischen 10 nm und 500 nm, vorzugsweise zwischen 40 und 150 nm. Die Ausdehnung in die beiden anderen Dimensionen beträgt zwischen 2 und 200 μm und insbesondere zwischen 5 und 50 μm.Mixtures with commercially available pigments, for example inorganic and organic absorption pigments, metallic effect pigments and LCP pigments, can also be used for this purpose. The pigments according to the invention are based on platelet-shaped titanium dioxide. These platelets have a thickness between 10 nm and 500 nm, preferably between 40 and 150 nm. The extent in the other two dimensions is between 2 and 200 μm and in particular between 5 and 50 μm.
Die Schicht eines anderen Metalloxids, die auf die Titandioxidplättchen aufgebracht wird, besitzt eine Dicke von 5 bis 300 nm, vorzugsweise zwischen 5 und 150 nm.The layer of another metal oxide which is applied to the titanium dioxide platelets has a thickness of 5 to 300 nm, preferably between 5 and 150 nm.
Die Herstellung der erfindungsgemäßen Pigmente erfolgt in einem dreistufigen Verfahren. In der ersten Stufe werden plättchenförmige Titandioxidpartikel mit Hilfe eines endlosen Bandes hergestellt.The pigments according to the invention are produced in a three-stage process. In the first stage, platelet-shaped titanium dioxide particles are produced using an endless belt.
Zunächst soll an Hand von Figur 1 das Bandverfahren erläutert werden.First of all, the belt process will be explained with reference to FIG. 1.
Das endlose Band 1 , welches über ein Rollensystem 2 geführt wird, durchläuft ein Auftragswerk 3, wo es mit einem dünnen Film des Precursors beschichtet wird. Als geeignete Auftragswerke können Walzenauftragswerke sowie Fließer eingesetzt werden. Die Bandgeschwindigkeit liegt zwischen 2 und 400 m/min, vorzugsweise 5 - 200 m/min.The endless belt 1, which is guided over a roller system 2, passes through an application unit 3, where it is coated with a thin film of the precursor. Roller applicators and flowers can be used as suitable applicators. The belt speed is between 2 and 400 m / min, preferably 5-200 m / min.
Um eine gleichmäßige Benetzung des Kunststoff bandes zu erzielen, ist es zweckmäßig, der Beschichtungslösung ein handelsübliches Netzmittel zu- zusetzen oder die Bandoberfläche durch Beflammung, Koronabehandlung oder Ionisation zu aktivieren.In order to achieve uniform wetting of the plastic tape, it is advisable to add a commercially available wetting agent to the coating solution or to activate the tape surface by flame treatment, corona treatment or ionization.
Anschließend durchläuft das beschichtete Band eine Trockenstrecke 4 in der die Schicht bei Temperaturen zwischen 30 und 200 °C getrocknet wird. Als Trockner können zum Beispiel handelsübliche Infrarot-, Umluftdüsen- und UV-Trockner eingesetzt werden. Nach dem Passieren der Trockenstrecke wird das Band durch die Ablösebäder 5 mit einem geeignetem Ablösemedium, zum Beispiel vollentsalztem Wasser geführt, wo die getrocknete Schicht vom Band entfernt wird. Der Ablösevorgang wird hierbei durch zusätzliche Vorrichtungen, zum Beispiel Düsen, Bürsten oder Ultraschall, unterstützt.The coated strip then runs through a drying section 4 in which the layer is dried at temperatures between 30 and 200 ° C. For example, commercially available infrared, circulating air and UV dryers can be used as dryers. After passing the drying section, the tape is passed through the release baths 5 with a suitable release medium, for example deionized water, where the dried layer is removed from the tape. The detachment process is supported by additional devices, for example nozzles, brushes or ultrasound.
In einem Nachtrockner 6 wird das Band vor der erneuten Beschichtung getrocknet.The tape is dried in a post-dryer 6 before it is re-coated.
Das endlose Band sollte aus einem chemisch und thermisch beständigem Kunststoff sein, um eine ausreichende Standzeit und hohe Trocknungstemperaturen zu gewährleisten. Hierfür sind Materialien wie Polyethylen- terephthalat (PET) oder andere Polyester und Polyacrylate geeignet.The endless belt should be made of a chemically and thermally resistant plastic to ensure a sufficient service life and high drying temperatures. Materials such as polyethylene terephthalate (PET) or other polyesters and polyacrylates are suitable for this.
Die Folienbreite liegt typischerweise zwischen einigen Zentimetern bis zu mehreren Metern. Die Dicke beträgt zwischen 10 μm bis zu einigen mm, wobei diese beiden Parameter im Hinblick auf die jeweiligen Anforderungen optimiert werden.The film width is typically between a few centimeters up to several meters. The thickness is between 10 μm and a few mm, whereby these two parameters are optimized with regard to the respective requirements.
Weitere Einzelheiten zu kontinuierlichen Bandverfahren sind aus US 3 138475, EP 0 240 952 und WO 93/08237 bekannt.Further details on continuous belt processes are known from US 3 138475, EP 0 240 952 and WO 93/08237.
Die vom Band abgelösten Titandioxidplättchen werden in einer zweiten Verfahrensstufe ohne vorherige Zwischentrocknung mit einem anderen Metalloxid nach bekanntem Verfahren beschichtet.The titanium dioxide flakes detached from the tape are coated in a second process step without prior drying with another metal oxide by a known method.
Bei der Beschichtung mit Hämatit (Fe203) kann sowohl von Eisen(lll)-sal- zen ausgegangen werden, wie es zum Beispiel in US 3 987 828 und US 3 087 829 beschrieben ist, als auch von Eisen(ll)-salzen, wie in US 3 874890 beschrieben, wobei der zunächst gebildete Überzug von Eisen(ll)-hydroxid zum Eisen(lll)-oxidhydrat oxidiert wird. Bevorzugt wird von Eisen(lll)-salzen ausgegangen. Hierzu wird einer wäßrigen Suspension der Titandioxidplättchen bei einer Temperatur von 60 bis 90 °C und bei einem pH-Wert von 2,5 bis 4,5 eine Eisen(lll)-chloridlösung zudosiert. Der pH-Wert wird durch gleichzeitige Dosierung von 32 %iger Natronlauge konstant gehalten. Nach Aufarbeitung und Trocknung bei 110 °C erhält man ein rotes Pigment.When coating with hematite (Fe 2 0 3 ), iron (III) salts can be used as described, for example, in US Pat. No. 3,987,828 and US Pat. No. 3,087,829, and iron (II) - salt, as described in US Pat. No. 3,874,890, the initially formed coating of iron (II) hydroxide being oxidized to the iron (III) oxide hydrate. The preferred starting point is iron (III) salts. For this purpose, an aqueous suspension of the titanium dioxide platelets at a temperature of 60 to 90 ° C and an iron (III) chloride solution is metered in at a pH of 2.5 to 4.5. The pH value is kept constant by simultaneous dosing of 32% sodium hydroxide solution. After working up and drying at 110 ° C., a red pigment is obtained.
Die Beschichtung mit Magnetit (Fe3θ4) erfolgt durch Hydrolyse einer Eisen(ll)-salzlösung, beispielsweise Eisen(ll)-sulfat, bei einem pH-Wert von 8,0 in Gegenwart von Kaliumnitrat. Die genauen Fällungsbeispiele sind in EP 0 659 843 beschrieben. Man erhält ein schwarzes Pigment nach Aufarbeitung und Trocknung bei 100 °C.The coating with magnetite (Fe 3 θ 4 ) is carried out by hydrolysis of an iron (II) salt solution, for example iron (II) sulfate, at a pH of 8.0 in the presence of potassium nitrate. The exact precipitation examples are described in EP 0 659 843. A black pigment is obtained after working up and drying at 100 ° C.
Bevorzugt ist auch eine Beschichtung der Titandioxidplättchen mit gelbem FeO(OH) in der Goethitmodifikation. Dabei wird zu einer Suspension der Titandioxidplättchen in einer Stickstoffatmosphäre bei 70 °C eine wäßrige FeS04-Lösung zudosiert. Anschließend wird mit einer 10 %igen Na2C03- Lösung der pH-Wert auf 4 eingestellt und Sauerstoff in die Suspension eingeleitet. Nach Aufarbeitung und Trocknung bei 110 °C erhält man ein gelbes Pigment. Bezüglich der genauen Fällungsbedingungen wird auf EP 0 659 843 verwiesen.A coating of the titanium dioxide platelets with yellow FeO (OH) in the goethite modification is also preferred. An aqueous FeS0 4 solution is metered into a suspension of the titanium dioxide platelets in a nitrogen atmosphere at 70 ° C. Then the pH is adjusted to 4 with a 10% Na 2 CO 3 solution and oxygen is introduced into the suspension. After working up and drying at 110 ° C., a yellow pigment is obtained. With regard to the exact precipitation conditions, reference is made to EP 0 659 843.
Für eine bessere Haftung der Eisenoxidschichten auf den Titandioxidplättchen ist es zweckmäßig, zuerst eine Zinnoxidschicht aufzubringen. Dabei wird zu der auf einen pH-Wert von 1 ,8 eingestellten Suspension der Titandioxidplättchen eine mit Salzsäure versetzte SnCU-Lösung zudosiert und der pH-Wert durch gleichzeitige Dosierung von 32 %iger Natronlauge konstant gehalten. Nach dem Auffällen der Zinndioxydhydratschicht kann dann unmittelbar die Beschichtung mit einem Eisenoxidhydrat angeschlossen werden.For better adhesion of the iron oxide layers on the titanium dioxide platelets, it is advisable to apply a tin oxide layer first. An SnCU solution mixed with hydrochloric acid is added to the suspension of the titanium dioxide platelets, which is adjusted to a pH value of 1.8, and the pH value is kept constant by simultaneous dosing of 32% sodium hydroxide solution. After the tin dioxide hydrate layer has been noticed, the coating with an iron oxide hydrate can then be connected immediately.
Ein anderes Metalloxid, das bevorzugt auf die Titandioxidplättchen aufgefällt wird, ist Chromoxid. Die Abscheidung kann leicht durch die thermische Hydrolyse, die bei der Verflüchtigung von Ammoniak aus einer wäßrigen Lösung eines Hexam- min-Chrom(lll)-Derivates eintritt, oder durch thermische Hydrolyse einer Chromsalzlösung, die mit Borax gepuffert ist, bewirkt werden. Die Be- Schichtung mit Chromoxid ist in US 3087828 und 3 087 829 beschrieben.Another metal oxide that is preferentially struck on the titanium dioxide platelets is chromium oxide. The deposition can easily be effected by the thermal hydrolysis which occurs when ammonia evaporates from an aqueous solution of a hexamine-chromium (III) derivative, or by thermal hydrolysis of a chromium salt solution which is buffered with borax. The coating with chromium oxide is described in US 3087828 and 3,087,829.
Die erfindungsgemäßen Pigmente müssen nicht in jedem Falle kalziniert werden. Für bestimmte Anwendungen genügt eine Trocknung bei Temperaturen von 110 °C. Wird das Pigment geglüht, werden Temperaturen zwi- sehen 400 °C und 1000 °C eingestellt, wobei der bevorzugte Bereich zwischen 400 °C und 700 °C liegt.The pigments according to the invention do not have to be calcined in every case. Drying at temperatures of 110 ° C is sufficient for certain applications. If the pigment is calcined, temperatures between 400 ° C and 1000 ° C are set, the preferred range being between 400 ° C and 700 ° C.
Das erfindungsgemäße Pigment kann noch zusätzlich mit schwerlöslichen, fest haftenden anorganischen oder organischen Farbmitteln beschichtet werden. Bevorzugt werden Farblacke und insbesondere Aluminiumfarblacke verwendet. Dazu wird eine Aluminiumhydroxidschicht aufgefällt, die in einem zweiten Schritt mit einem Farblack verlackt wird. Das Verfahren ist in DE 24 29 762 und DE 29 28 287 näher beschrieben.The pigment of the invention can additionally be coated with sparingly soluble, firmly adhering inorganic or organic colorants. Colored lacquers and in particular aluminum colored lacquers are preferably used. For this purpose, an aluminum hydroxide layer is struck, which is then varnished with a colored varnish. The process is described in more detail in DE 24 29 762 and DE 29 28 287.
Bevorzugt ist auch eine zusätzliche Beschichtung mit Komplexsalzpigmenten, insbesondere Cyanoferratkomplexen, wie zum Beispiel Berliner Blau und Turnbulls Blau, wie sie in EP 0 141 173 und DE 23 13 332 beschrieben ist.An additional coating with complex salt pigments, in particular cyanoferrate complexes, such as for example Berliner Blau and Turnbulls Blau, as described in EP 0 141 173 and DE 23 13 332, is also preferred.
Das erfindungsgemäße Pigment kann auch mit organischen Farbstoffen und insbesondere mit Phthalocyanin- oder Metallphthalocyanin- und/oder Indanthrenfarbstoffen nach DE 40 09 567 beschichtet werden. Dazu wird eine Suspension des Pigmentes in einer Lösung des Farbstoffes hergestellt und diese dann mit einem Lösungsmittel zusammengebracht, in wel- ehern der Farbstoff schwer löslich oder unlöslich ist.The pigment according to the invention can also be coated with organic dyes and in particular with phthalocyanine or metal phthalocyanine and / or indanthrene dyes according to DE 40 09 567. For this purpose, a suspension of the pigment is prepared in a solution of the dye and this is then brought together with a solvent in which the dye is sparingly soluble or insoluble.
Weiterhin können auch Metallchalkogenide bzw. Metallchalkogenid- hydrate und Ruß für eine zusätzliche Beschichtung eingesetzt werden. Es ist weiterhin möglich, die Pigmente einer Nachbeschichtung oder Nachbehandlung zu unterziehen, die die Licht-, Wetter- und chemische Stabilität weiter erhöht, oder die Handhabung des Pigments, insbesondere die Einarbeitung in unterschiedliche Medien, erleichtert. Als Nachbe- Schichtungen kommen beispielsweise die in den DE-PS 22 15 191 , DE-Metal chalcogenides or metal chalcogenide hydrates and carbon black can also be used for an additional coating. It is also possible to subject the pigments to a post-coating or post-treatment which further increases the light, weather and chemical stability, or to facilitate the handling of the pigment, in particular the incorporation into different media. The following layers are, for example, those described in DE-PS 22 15 191, DE-
OS 31 51 354, DE-OS 3235017 oder DE-OS 3334598 beschriebenen Verfahren in Frage. Aufgrund der bereits ohne diese zusätzlichen Maßnahmen sehr guten Eigenschaften der erfindungsgemäßen Pigmente machen diese ggf. noch aufgebrachten Stoffe nur etwa 0 bis 5, insbeson- dere etwa 0 bis 3 Gew.% des gesamten Pigments aus.OS 31 51 354, DE-OS 3235017 or DE-OS 3334598 methods described in question. Owing to the very good properties of the pigments according to the invention even without these additional measures, these substances which may still be applied make up only about 0 to 5, in particular about 0 to 3% by weight of the total pigment.
Die erfindungsgemäßen Pigmente stellen bezüglich der Dicke den Idealzustand dar, der bei Perlglanzpigmenten maximal erreichbar ist, da sie nur aus optisch funktionellen Schichten bestehen und ein sonst übliches Trä- germaterial, wie beispielsweise Glimmer oder Glasplättchen, das nicht zum optischen Effekt beiträgt, fehlt. Bedingt durch die Dicke des Glimmers besitzen Glimmerpigmente eine bis um den Faktor 25 größere Dicke bei gleicher Dicke der funktionellen Schichten. Bezüglich der technischen Anwendungen ergeben sich hieraus intrinsische Vorteile, die von keinem anderen konventionellen Perlglanzpigment erreicht werden können. Beispielsweise können Lackschichten dünner ausgeführt werden und die notwendige Pigmentmenge kann reduziert werden, weil aufgrund des Fehlens des "Füllstoffs" Trägermaterial die Pigmente optisch aktiver sind.With regard to the thickness, the pigments according to the invention represent the ideal state which can be attained as far as possible with pearlescent pigments, since they consist only of optically functional layers and an otherwise customary carrier material, such as mica or glass plates, which does not contribute to the optical effect, is missing. Due to the thickness of the mica, mica pigments are up to 25 times thicker with the same thickness of the functional layers. With regard to technical applications, this results in intrinsic advantages that no other conventional pearlescent pigment can achieve. For example, lacquer layers can be made thinner and the necessary amount of pigment can be reduced because the pigments are more optically active due to the lack of the “filler” carrier material.
Die nachfolgenden Beispiele sollen die Erfindung erläutern, ohne sie zu begrenzen. The following examples are intended to illustrate the invention without limiting it.
Beispiel 1example 1
Ein umlaufendes Band aus Polyethylenterephthalat (Breite: 0,3m, Geschwindigkeit: 20 m/min) wird über eine Auftragswalze im Gegenlauf mit einer 20%iger Titantetrachloridlösung beschichtet. Die Beschichtungs- lösung enthält 0,3 Gew.-% Tensid (DISPERSE-AYD W-28, Hersteller: DANIEL PRODUCTS COMPANY). Der auf dem Band befindliche wäßrige Film wird in einer Trocknungsstrecke durch Beaufschlagung mit Heißluft von 70 °C getrocknet und die gebildete Schicht in einem mit vollentsalztem Wasser gefüllten Ablösebecken vom Band abgelöst. Die plättchenförmi- gen Titandioxidpartikel werden filtriert und mit vollentsalztem Wasser gewaschen. Die silbrig glänzenden Plättchen haben eine Schichtdicke von 100 ± 10 nm. Zur Beschichtung mit einem anderen Metalloxid werden sie in vollentsalztem Wasser redispergiert.A circumferential belt made of polyethylene terephthalate (width: 0.3 m, speed: 20 m / min) is coated with a 20% titanium tetrachloride solution in counter-rotation on an application roller. The coating solution contains 0.3% by weight of surfactant (DISPERSE-AYD W-28, manufacturer: DANIEL PRODUCTS COMPANY). The aqueous film on the belt is dried in a drying section by exposure to hot air at 70 ° C. and the layer formed is detached from the belt in a detachment basin filled with deionized water. The platelet-shaped titanium dioxide particles are filtered and washed with deionized water. The silvery, shiny platelets have a layer thickness of 100 ± 10 nm. To coat them with another metal oxide, they are redispersed in deionized water.
2 I der Dispersion (Trockensubstanzgehalt: 15 g Tiθ2) werden auf 75 °C erhitzt und mit verdünnter Salzsäure auf einen pH-Wert von 1 ,8 eingestellt.2 l of the dispersion (dry matter content: 15 g TiO 2) are heated to 75 ° C. and adjusted to a pH of 1.8 with dilute hydrochloric acid.
4,3 g SnCl4 • 5 H2O werden in 29 ml HCI gelöst, mit destilliertem Wasser auf 290 ml aufgefüllt und 10 min gerührt.4.3 g of SnCl4 • 5 H2O are dissolved in 29 ml of HCl, made up to 290 ml with distilled water and stirred for 10 min.
Die Snd4-Lösung wird mit 3 ml/min zur Tiθ2-Suspension zugegeben und dabei der pH 1 ,8 mit 32%iger NaOH-Lösung konstant gehalten. Nach der Snθ2-Belegung wird die Suspension 15 min bei konstanter Temperatur und konstantem pH-Wert nachgerührt.The Snd4 solution is added to the TiO 2 suspension at 3 ml / min and the pH 1.8 is kept constant with 32% NaOH solution. After the SnO 2 coating, the suspension is stirred for 15 minutes at constant temperature and pH.
Anschließend wird der pH-Wert mit 32 %iger NaOH-Lösung auf 3,0 eingestellt und eine wäßrige 8 %ige Eisen(lll)-chloridlösung mit einer Geschwindigkeit von 3 ml/min zudosiert, wobei der pH-Wert durch gleichzeitige Zugabe der NaOH-Lösung konstant gehalten wird. Die FeCI3-Zu- gabe wird fortgesetzt bis die gewünschte Interferenzfarbe erreicht ist. Das erhaltene Pigment wird abfiltriert, mit vollentsalztem Wasser gewaschen und bei 110 °C 12 Stunden getrocknet. Das Pigment besitzt die ge- wünschte Interferenzfarbe und eine rote Körperfarbe. The pH is then adjusted to 3.0 with 32% NaOH solution and an aqueous 8% iron (III) chloride solution is metered in at a rate of 3 ml / min, the pH being increased by simultaneous addition of the NaOH Solution is kept constant. The FeCI 3 addition is continued until the desired interference color is reached. The pigment obtained is filtered off, washed with deionized water and dried at 110 ° C. for 12 hours. The pigment has the desired interference color and a red body color.

Claims

Patentansprüche claims
1. Farbiges Perlglanzpigment, bestehend aus einem Kern aus plätt- chenförmigem Titandioxid und einer oder mehrerer Schichten aus anderen Metalloxiden bzw. Metalloxidhydraten, erhältlich durch Verfestigung einer wäßrigen Lösung einer thermisch hydrolisierbaren Titanverbindung auf einem endlosen Band, Ablösung der entstandenen Schicht, Beschichtung der erhaltenen Titandioxidplättchen nach oder ohne Zwischentrocknung im Naßverfahren mit einem oder meh- reren anderen Metalloxiden bzw. Metalloxidhydraten, Abtrennung,1. Colored pearlescent pigment, consisting of a core of platelet-shaped titanium dioxide and one or more layers of other metal oxides or metal oxide hydrates, obtainable by solidifying an aqueous solution of a thermally hydrolyzable titanium compound on an endless belt, detaching the resulting layer, coating the titanium dioxide platelets obtained after or without intermediate drying in the wet process with one or more other metal oxides or metal oxide hydrates, separation,
Trocknung und gegebenenfalls Kalzination des erhaltenen Materials.Drying and optionally calcination of the material obtained.
2. Perlglanzpigment nach Anspruch 1 , dadurch gekennzeichnet, daß das andere Metalloxid Fe203, Fe3θ4, FeOOH oder Cr203 ist.2. Pearlescent pigment according to claim 1, characterized in that the other metal oxide is Fe 2 0 3 , Fe 3 θ 4 , FeOOH or Cr 2 0 3 .
3. Verfahren zur Herstellung des Perlglanzpigmentes nach den Ansprüchen 1 bis 2, dadurch gekennzeichnet, daß3. A process for the preparation of the pearlescent pigment according to claims 1 to 2, characterized in that
eine wäßrige Lösung einer thermisch hydrolysierbaren Titan- Verbindung als dünner Film auf ein endloses Band aufgebracht wird,an aqueous solution of a thermally hydrolyzable titanium compound is applied as a thin film to an endless belt,
der flüssige Film durch Trocknung verfestigt wird und dabei das Titandioxid durch eine chemische Reaktion aus der Lösung entwickelt wird,the liquid film is solidified by drying and the titanium dioxide is developed from the solution by a chemical reaction,
die entstandene Schicht anschließend vom Band abgelöst und gewaschen wird,the resulting layer is then removed from the belt and washed,
- die erhaltenen Titandioxidplättchen nach oder ohne Zwischentrocknung in Wasser suspendiert und mit einem oder mehreren Metalloxiden beschichtet werden, die beschichteten Titandioxidplättchen aus der wäßrigen Suspension abgetrennt, getrocknet und gegebenenfalls kalziniert werden.the titanium dioxide platelets obtained are suspended in water after or without intermediate drying and coated with one or more metal oxides, the coated titanium dioxide platelets are separated from the aqueous suspension, dried and optionally calcined.
4. Verfahren nach den Anspruch 3, dadurch gekennzeichnet, daß die wäßrige Lösung einer thermisch hydrolisierbaren Titanverbindung eine wäßrige Titantetrachloridlösung ist.4. The method according to claim 3, characterized in that the aqueous solution of a thermally hydrolyzable titanium compound is an aqueous titanium tetrachloride solution.
5. Verfahren nach den Ansprüchen 3 und 4, dadurch gekennzeichnet, daß als andere Metalloxide Fe203, Fe3θ4, FeOOH und Cr203 eingesetzt werden.5. Process according to claims 3 and 4, characterized in that Fe 2 0 3 , Fe 3 θ 4 , FeOOH and Cr 2 0 3 are used as other metal oxides.
6. Verfahren nach mindestens einem der Ansprüche 3 bis 5, dadurch gekennzeichnet, daß das Pigment bei Temperaturen von 110 bis 150 °C getrocknet wird.6. The method according to at least one of claims 3 to 5, characterized in that the pigment is dried at temperatures of 110 to 150 ° C.
7. Verfahren nach mindestens einem der Ansprüche 3 bis 6, dadurch gekennzeichnet, daß das Pigment bei Temperaturen von 400 bis 700 °C kalziniert wird.7. The method according to at least one of claims 3 to 6, characterized in that the pigment is calcined at temperatures from 400 to 700 ° C.
8. Verfahren nach mindestens einem der Ansprüche 3 bis 7, dadurch gekennzeichnet, daß das andere Metalloxid bzw. weitere Metalloxide in einem Wirbelbettreaktor durch CVD auf die Titandioxidplättchen aufgebracht werden.8. The method according to at least one of claims 3 to 7, characterized in that the other metal oxide or further metal oxides are applied in a fluidized bed reactor by CVD to the titanium dioxide platelets.
9. Verwendung der Pigmente gemäß den Ansprüchen 1 und 2 zur Pigmentierung von Lacken, Druckfarben, Kunststoffen, Kosmetika und Glasuren für Keramiken und Gläser.9. Use of the pigments according to claims 1 and 2 for pigmenting paints, printing inks, plastics, cosmetics and glazes for ceramics and glasses.
10. Verwendung nach Anspruch 9, dadurch gekennzeichnet, daß die10. Use according to claim 9, characterized in that the
Pigmente als Mischungen mit handelsüblichen Pigmenten eingesetzt werden.Pigments can be used as mixtures with commercially available pigments.
11. Lacke, Druckfarben, Kunststoffe und Kosmetika, welche mit einem Pigment nach den Ansprüchen 1 und 2 pigmentiert sind. 11. Lacquers, printing inks, plastics and cosmetics which are pigmented with a pigment according to claims 1 and 2.
PCT/EP1997/002650 1996-05-09 1997-05-23 Metal oxide coated titanium dioxide lamellas WO1998053010A1 (en)

Priority Applications (7)

Application Number Priority Date Filing Date Title
DE19618568A DE19618568A1 (en) 1996-05-09 1996-05-09 Coloured, uniformly thick nacreous titanium di:oxide pigments with metal oxide coating
EP97923992A EP0931112B1 (en) 1997-05-23 1997-05-23 Metal oxide coated titanium dioxide lamellas
DE59709110T DE59709110D1 (en) 1997-05-23 1997-05-23 METAL OXIDE COATED TITANIUM DIOXIDE PLATES
JP10549831A JP2000515927A (en) 1997-05-23 1997-05-23 Titanium dioxide flake coated with metal oxide
BR9710754-9A BR9710754A (en) 1997-05-23 1997-05-23 Platelets of titanium dioxide coated with metal oxide.
US09/230,261 US6238472B1 (en) 1997-05-23 1997-05-23 Metal oxide coated titanium dioxide lamellas
PCT/EP1997/002650 WO1998053010A1 (en) 1996-05-09 1997-05-23 Metal oxide coated titanium dioxide lamellas

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DE19618568A DE19618568A1 (en) 1996-05-09 1996-05-09 Coloured, uniformly thick nacreous titanium di:oxide pigments with metal oxide coating
PCT/EP1997/002650 WO1998053010A1 (en) 1996-05-09 1997-05-23 Metal oxide coated titanium dioxide lamellas

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CN104069847A (en) * 2014-04-10 2014-10-01 西安工程大学 Preparation method of rear earth europium doped hollow nano TiO2 glass micro beads

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DE10041979A1 (en) * 2000-08-26 2002-03-14 Basf Coatings Ag Use of lamellar effect pigments based on iron oxide to increase the covering power of coatings, e.g. automobile lacquers
US6485556B1 (en) * 2001-10-10 2002-11-26 Engelhard Corporation Interference pigments
DE102009051171A1 (en) 2009-10-29 2011-05-05 Merck Patent Gmbh pigments
EP2559739B1 (en) * 2011-08-16 2014-04-16 JDS Uniphase Corporation Manufacturing of diffractive pigments by fluidized bed chemical vapor deposition
DE102013012023A1 (en) 2013-07-19 2015-01-22 Merck Patent Gmbh pigment mixture
DE102016004164A1 (en) 2016-04-11 2017-10-12 Merck Patent Gmbh pigment mixture
EP3517579B1 (en) 2018-01-23 2022-10-26 Merck Patent GmbH Pigment mixture comprising red, blue and green interference pigments
DE102019003073A1 (en) 2019-04-30 2020-11-05 Merck Patent Gmbh Pigment / frit mixture
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