Classifications

• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09C—TREATMENT OF INORGANIC MATERIALS, OTHER THAN FIBROUS FILLERS, TO ENHANCE THEIR PIGMENTING OR FILLING PROPERTIES ; PREPARATION OF CARBON BLACK  ; PREPARATION OF INORGANIC MATERIALS WHICH ARE NO SINGLE CHEMICAL COMPOUNDS AND WHICH ARE MAINLY USED AS PIGMENTS OR FILLERS
  • C09C1/00—Treatment of specific inorganic materials other than fibrous fillers; Preparation of carbon black
  • C09C1/40—Compounds of aluminium
  • C09C1/42—Clays
• • 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
  • C01—INORGANIC CHEMISTRY
  • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
  • C01P2002/00—Crystal-structural characteristics
  • C01P2002/20—Two-dimensional structures
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
  • C01P2002/00—Crystal-structural characteristics
  • C01P2002/20—Two-dimensional structures
  • C01P2002/22—Two-dimensional structures layered hydroxide-type, e.g. of the hydrotalcite-type
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
  • C01P2004/00—Particle morphology
  • C01P2004/20—Particle morphology extending in two dimensions, e.g. plate-like
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
  • C01P2004/00—Particle morphology
  • C01P2004/54—Particles characterised by their aspect ratio, i.e. the ratio of sizes in the longest to the shortest dimension
• • 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
  • C09C2200/102—Interference pigments characterized by the core material the core consisting of glass or silicate material like mica or clays, e.g. kaolin

Definitions

• Air gap interference pigments their production and use
• the invention relates to platelet-shaped pigments which differ from previously known pigments by a new, characteristic structure.
• colorants are divided into inorganic and organic colorants.
• the inorganic colorants include the inorganic pigments, which are further converted into inorganic white pigments (e.g. barium sulfate, titanium dioxide, zinc oxide), inorganic colored pigments (e.g. chrome yellow, iron oxide red, cobalt blue), inorganic black pigments (e.g. iron oxide black, pigment black), inorganic luminous pigments (e.g. phosphorescent pigments fluorescent pigments) and inorganic gloss pigments.
• inorganic white pigments e.g. barium sulfate, titanium dioxide, zinc oxide
• inorganic colored pigments e.g. chrome yellow, iron oxide red, cobalt blue
• inorganic black pigments e.g. iron oxide black, pigment black
• inorganic luminous pigments e.g. phosphorescent pigments fluorescent pigments
• inorganic gloss pigments e.g. phosphorescent pigments fluorescent pigments
• These pigments are essentially based on purely metallic reflection. Without going into the theory of metallic reflection in detail, it can also be understood as a refraction, but due to the very high refractive index of the metal, the light only enters the surface for a very short distance, on the order of magnitude less angstroms, and is then reflected. Examples of such metallic effect pigments are aluminum and copper-zinc alloys.
• Pearlescent pigments have a platelet-shaped substrate which has a diameter / thickness ratio of at least 1:50, but usually 1: 100 and above and which is covered with a thin layer of a highly light-refractive oxide.
• a high refractive index difference must exist between the platelet-shaped substrate and the applied oxide layer, for example as with mica 1.5 and rutile 2.6 to 2.9 or other metal oxides to 3.
• the oxide layer applied to the platelet-shaped substrate must be tight and without an air layer issue.
• the thickness of the oxide layer must be such that light rays reflected on the surface as a result of the high refractive index differences come to interference.
• Examples of such pearlescent pigments are titanium dioxide on mica, see here for example
• the pearlescent pigments thus represent interference pigments in which the above-mentioned features are realized.
• the effect of the pearlescent pigments is largely dependent on the grain size or the platelet diameter. With a diameter of less than 15 ⁇ m, the pearlescent pigments only have a matt, diffuse, not very strong pearlescent effect and good hiding power, with grain sizes between 5 and 25 ⁇ m they have a silk gloss and moderate hiding power, with a grain size between 10 and 40 ⁇ m they have a pronounced pearlescent and medium hiding power, with a grain size between 3 and 10 ⁇ m they have a shimmering pearlescent with a low hiding power and with a grain size between 20 and 200 ⁇ m they have a tinsel luster with poor hiding power.
• Hiding power is understood here to mean the covering power on a normative base when the respective pigment is stirred into a transparent or film-forming organic binder, it being noted that such pigments can only be used in organic binders, but not in inorganic binders.
• the colored interference pigments can be divided into two groups:
• Fire-colored metal bronzes which are obtained by coating metals by oxidative treatment of the surface with a thin metal oxide layer, which is translucent due to the small thickness.
• the metal-reflecting substrate reflects the light passing through the oxide layer almost completely and interference occurs in the penetrating and reflected beam, which leads to color effects in connection with the oxide color.
• interference colors of a clear type appear, which give rise to a gold tone, a silver tone, a red tone, a green tone, etc., whereas the previously mentioned pearlescent pigments show a colored pearlescent luster.
• Colored pearlescent pigments multi-layer interference absorption pigments: The same requirements apply as for pearlescent pigments, but in addition to the titanium dioxide layer there is another layer of a translucent but light-absorbing oxide, such as iron oxide or chromium oxide. Examples of such pigments are iron oxide over titanium oxide on mica. Depending on the thickness of the oxide layers, interference pigments with a pronounced metal character, such as silver, gold, bronze, or also extremely colored pigments are formed.
• Air gap interference pigments :
• the new air gap interference pigments differ from the pearlescent pigments and the colored interference pigments in that the colors are caused by air gaps between them, which are very small, for example in the range of 1/10 ⁇ m and even significantly less.
• the material layer lying above and below the air gaps can consist of the same material and thus also have the same refractive index.
• the refractive index itself can be small and be of the order of 1.5 to 1.6 (biotite 1.6 to 1.66, muscovite 1.55 to 1.64, vermiculite 1.58, pyrophyllite 1.55 to 1 , 6, talc 1.58 to 1.54).
• the diameter / thickness ratio of the platelet-shaped substrate can be in the range from 1: 5 to a maximum of 1:50.
• the substrate must be platelet-shaped; the diameter / thickness ratio of the plate can be well below 50; in the platelet itself there must be fine air gaps with a thickness of significantly less than 1 ⁇ m, so that the platelet is made up of platelet-shaped solid substance-air gap-platelet-shaped solid substance; the refractive index of the platelet-shaped substrate can be low, around 1.5 or below; in contrast to the pearlescent pigments and the colored interference pigments, after the production of the air gap interference pigments, these can be subjected to a post-grinding, whereby the grain sizes can be approached down to the smallest unit, in which at least one layer package of solid substance-air gap solid substance is also contained . Furthermore, there must not be as much plane parallelism between the top and bottom of the plate as with pearlescent pigments or colored pearlescent pigments.
• the present invention thus relates to platelet-shaped air gap interference pigments which are distinguished by closely adjacent layers of medium to low refractive index minerals with interposed air gaps of less than 1 ⁇ m in thickness.
• the platelets have a diameter / thickness ratio in the range from 1: 5 to 1:50.
• the mineral layers can be monomineral or heteromineral. A high plane parallelism is not necessary.
• each substrate is colored, add a certain additive color to the interferences solid-air gap-solid or solid-gas-solid. If, for example, the substrate with a low refractive index has a somewhat gray to bluish tint, a silver effect is produced; if the substrate has a brownish tint, then there is a gold effect; if the substrate has a greenish tint, a silver-bronze effect is produced.
• the air gap must not exceed 1 ⁇ m. If it were too large, when the pigment is embedded in a binder, it enters the air gap. However, if the organic binding agent entered the air gap, this would be eliminated and the desired gloss effect would inevitably disappear.
• phyllosilicates (leaf silicates) are of particular interest, in which the essential component of the silicates, the SiO 4 tetrahedra, is two-dimensionally networked in rings.
• Phyllosilicates are characterized by a platelet shape and excellent splittability perpendicular to the platelet axis.
• two structural elements can be distinguished in phyllosilicates, namely a tetrahedral layer (Si, Al, Fe 3 ) and an octahedral layer with octahedral medium-sized cations.
• the phyllosilicates can be systematically built up through a variable combination of the octahedron and tetrahedron layers, which are divided into two-layer, three-layer and four-layer minerals.
• Specific examples of phyllosilicates which can be used according to the invention are mica, hydro-mica, illite, muscovite, biotite, phlogopite, pyrophtyllite, chlorite and talc.
• the formation of layers of medium-low to low-index minerals with intermediate, at most 1 ⁇ m thick thin air gaps, essential to the invention can be brought about by the fact that three- and four-layer phyllosilicates undergo a temperature treatment above the H 2 O-, OH- or fluorine - be subjected to the escape temperature.
• a temperature treatment only water up to a temperature of about 250 ° C. is expelled first, from a temperature in the larger range of 400 to 600 ° C. then also OH and F. Later, new phases are formed, with the OH ions escaping between there are several 100 ° temperature differences between the grid and the emergence of the new phases can.
• manipulation of the color can be brought about by leaching the phyllosilicates with chemicals.
• the leaching can take place before and / or after the temperature treatment and can be carried out with acids, preferably hydrochloric acid, or by adding foreign ions, expediently as leaching in corresponding salt solutions, as hydrothermal treatment or as pressure treatment or vacuum treatment in such salt solutions.
• the temperature treatment according to the invention can be carried out both in normal air, in inert gases, in a reducing atmosphere or in a pure oxygen atmosphere.
• the use of different atmospheres in temperature treatment creates special effects by forcing ion types with several valences into certain valences.
• chlorite which takes on a gold effect (trivalent iron) during a temperature treatment in an oxidizing atmosphere (air)
• a silver effect can be achieved by temperature treatment in an inert atmosphere.
• platelet-shaped air gap interference pigments according to the invention no change in grinding. They are weather-resistant and chemically inert and are therefore suitable for use in a wide variety of areas, in particular for pigmentation, effecting, coloring and utilizing the platelet structure in pigment pastes, paints and varnishes based on organic and inorganic binders, paper and cardboard, building materials, plastics, alloys and melts, ceramics and glasses, roof coatings and cosnetics (personal care products).
• binder decomposition does not occur, as is the case with titanium dioxide modifications.
• the procedure for producing the platelet-shaped air gap interference pigments according to the invention is as follows:
• the 0.125 to 0.5 mm fraction is sieved out of the mined raw material and subjected to gravity sorting.
• the fraction with predominantly platelet-shaped material is submitted to a strong field magnetic separation and the magnetic fraction is separated off.
• This concentrate is calcined at 500 to 1,100 ° C; the burning time depends on the grain distribution and composition.
• the calcined product is ground and sieved into the desired grain fractions.
• Plastics and casting resins can be formulated, for example, from 70% by weight polyester resin and 30% by weight air gap interference pigment.
• a decorative resin, for example for surfboards, can be built up from 98% by weight of casting resin and 2% by weight of air gap interference pigment.
• the new air gap interference pigments can be used, for example, as a scattering agent for wallpapers; in the ceramic field, the new pigments can be embedded in the glaze or directly in the fragments.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Dispersion Chemistry (AREA)
• Paints Or Removers (AREA)
• Pigments, Carbon Blacks, Or Wood Stains (AREA)
• Coloring (AREA)
• Inks, Pencil-Leads, Or Crayons (AREA)
• Cosmetics (AREA)
• Silicates, Zeolites, And Molecular Sieves (AREA)
• Paper (AREA)
• Road Signs Or Road Markings (AREA)
• Steroid Compounds (AREA)

Applications Claiming Priority (2)

Publications (2)

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• 1988
  • 1988-05-26 AT AT0138588A patent/AT405838B/de not_active IP Right Cessation
• 1989
  • 1989-05-26 AU AU36837/89A patent/AU3683789A/en not_active Abandoned
  • 1989-05-26 HU HU893639A patent/HUT52537A/hu unknown
  • 1989-05-26 FI FI900400A patent/FI900400A0/fi not_active IP Right Cessation
  • 1989-05-26 AT AT89906006T patent/ATE78846T1/de not_active IP Right Cessation
  • 1989-05-26 EP EP89906006A patent/EP0368973B1/de not_active Expired
  • 1989-05-26 JP JP1505301A patent/JPH02504527A/ja active Pending
  • 1989-05-26 WO PCT/AT1989/000053 patent/WO1989011508A1/de not_active Ceased
• 1990
  • 1990-01-25 DK DK020390A patent/DK20390A/da not_active Application Discontinuation

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