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
  • C09C1/04—Compounds of zinc
  • C09C1/043—Zinc oxide
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K8/00—Cosmetics or similar toiletry preparations
  • A61K8/02—Cosmetics or similar toiletry preparations characterised by special physical form
  • A61K8/0241—Containing particulates characterized by their shape and/or structure
• • 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
  • A61K8/27—Zinc; Compounds thereof
• • 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
  • A61K8/72—Cosmetics or similar toiletry preparations characterised by the composition containing organic macromolecular compounds
  • A61K8/84—Cosmetics or similar toiletry preparations characterised by the composition containing organic macromolecular compounds obtained by reactions otherwise than those involving only carbon-carbon unsaturated bonds
  • A61K8/86—Polyethers
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P31/00—Antiinfectives, i.e. antibiotics, antiseptics, chemotherapeutics
  • A61P31/04—Antibacterial agents
• • 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
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B82—NANOTECHNOLOGY
  • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
  • B82Y30/00—Nanotechnology for materials or surface science, e.g. nanocomposites
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
  • C01G1/00—Methods of preparing compounds of metals not covered by subclasses C01B, C01C, C01D, or C01F, in general
  • C01G1/02—Oxides
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
  • C01G23/00—Compounds of titanium
  • C01G23/04—Oxides; Hydroxides
  • C01G23/047—Titanium dioxide
  • C01G23/053—Producing by wet processes, e.g. hydrolysing titanium salts
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
  • C01G25/00—Compounds of zirconium
  • C01G25/02—Oxides
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
  • C01G3/00—Compounds of copper
  • C01G3/02—Oxides; Hydroxides
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
  • C01G45/00—Compounds of manganese
  • C01G45/02—Oxides; Hydroxides
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
  • C01G49/00—Compounds of iron
  • C01G49/02—Oxides; Hydroxides
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
  • C01G51/00—Compounds of cobalt
  • C01G51/04—Oxides; Hydroxides
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
  • C01G53/00—Compounds of nickel
  • C01G53/04—Oxides; Hydroxides
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
  • C01G9/00—Compounds of zinc
  • C01G9/02—Oxides; Hydroxides
• • 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
  • A61K2800/60—Particulates further characterized by their structure or composition
  • A61K2800/61—Surface treated
  • A61K2800/614—By macromolecular compounds
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B82—NANOTECHNOLOGY
  • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
  • B82Y40/00—Manufacture or treatment of nanostructures
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
  • C01P2004/00—Particle morphology
  • C01P2004/60—Particles characterised by their size
  • C01P2004/64—Nanometer sized, i.e. from 1-100 nanometer

Definitions

• the present invention relates to processes for the preparation of surface-modified nanoparticulate particles of at least one metal oxide, metal hydroxide and / or metal oxide hydroxide and of aqueous suspensions of these particles. Furthermore, the invention relates to the surface-modified nanoparticulate particles obtainable by these processes of at least one metal oxide, metal hydroxide and / or metal oxide hydroxide and aqueous suspensions of these particles and their use for cosmetic sunscreen preparations, as a stabilizer in plastics and as an antimicrobial agent.
• Metal oxides are used for a variety of purposes, such.
• As a white pigment as a catalyst, as part of antibacterial skin protection creams and as an activator for the rubber vulcanization.
• In cosmetic sunscreens there are finely divided zinc oxide or titanium dioxide as UV-absorbing pigments.
• Nanoparticles are particles of the order of nanometers. Their size is in the transition region between atomic or monomolecular systems and continuous macroscopic structures. In addition to their usually very large surface, nanoparticles are characterized by particular physical and chemical properties, which differ significantly from those of larger particles. For example, nanoparticles often have a lower melting point, absorb light only at shorter wavelengths, and have different mechanical, electrical, and magnetic properties than macroscopic particles of the same material. By using nanoparticles as building blocks, many of these special properties can also be used for macroscopic materials (Winnacker / Kuchler, Chemical Engineering: Processes and Products, (Ed .: R. Dittmayer, W. Keim, G. Kreysa, A. Oberholz ), Vol. 2: New Technologies, Chapter 9, Wiley-VCH Verlag 2004).
• nanoparticles refers to particles having a mean diameter of from 1 to 500 nm, determined by means of electron microscopy methods.
• Nanoparticulate zinc oxide with particle sizes below about 100 nm is potentially suitable for use as a UV absorber in transparent organic-inorganic hybrid materials, plastics, paints and coatings. In addition, it can also be used to protect UV-sensitive organic pigments.
• Particles, particle aggregates or agglomerates of zinc oxide which are greater than about 100 nm, lead to stray light effects and thus to an undesirable decrease Transparency in the field of visible light. Therefore, the redispersibility, ie the convertibility of the nanoparticulate zinc oxide produced into a colloidal disperse state, is an important prerequisite for the abovementioned applications.
• Nanoparticulate zinc oxide with particle sizes below about 5 nm show a blue shift of the absorption edge due to the size quantization effect (L. Brus, J. Phys. Chem. (1986), 90, 2555-2560) and are therefore suitable for use as UV absorbers in UV -A area less suitable.
• finely divided metal oxides for example of zinc oxide
• dry and wet processes The classical incineration method of zinc, known as the dry process (eg, Gmelin volume 32, 8th Ed., Supplementary Volume, pp. 772 et seq.), Produces aggregated particles with a broad size distribution.
• dispersions having average particle sizes in the lower nanometer range can only be obtained from such powders with great difficulty by virtue of the shearing forces which can be achieved being too low.
• Particularly finely divided zinc oxide is mainly produced wet-chemically by precipitation processes.
• the precipitation in aqueous solution generally yields hydroxide and / or carbonate-containing materials which must be thermally converted to zinc oxide.
• the thermal aftertreatment has a negative effect on fineness, since the particles are subjected to sintering processes which lead to the formation of micrometer-sized aggregates, which can only be broken down to the primary particles by grinding in an incomplete manner.
• Nanoparticulate metal oxides can be obtained, for example, by the microemulsion method.
• a solution of a metal alkoxide is added dropwise to a water-in-oil microemulsion.
• the hydrolysis of the alkoxides to the nanoparticulate metal oxide takes place.
• the disadvantages of this method are, in particular, that the metal alkoxides are expensive starting materials, that in addition emulsifiers must be used and that the preparation of the emulsions with droplet sizes in the nanometer range represents a complex process step.
• nanoparticulate zinc oxide prepared by a precipitation reaction.
• the nanoparticulate zinc oxide is prepared starting from a zinc acetate solution via an alkaline precipitation.
• the centrifuged zinc oxide can be redispersed by addition of methylene chloride to a sol.
• the zinc oxide dispersions prepared in this way have the disadvantage that they have no good long-term stability owing to the lack of surface modification.
• zinc oxide gels are described which contain nanoparticulate zinc oxide with a particle diameter of ⁇ 15 nm and which are redispersible to sols.
• the solids produced by basic hydrolysis of a zinc compound in alcohol or in an alcohol / water mixture are redispersed by the addition of dichloromethane or chloroform.
• the disadvantage here is that no stable dispersions are obtained in water or in aqueous dispersants.
• WO 93/21127 describes a process for producing surface-modified nanoparticulate ceramic powders.
• a nanoparticulate ceramic powder is surface-modified by applying a low molecular weight organic compound, for example, propionic acid.
• a low molecular weight organic compound for example, propionic acid.
• This method can not be used for the surface modification of zinc oxide since the modification reactions are carried out in aqueous solution and zinc oxide dissolves in aqueous organic acids. Therefore, this method can not be used for the production of
• zinc oxide in this application is also not mentioned as a possible starting material for nanoparticulate ceramic powders.
• WO 02/42201 a process for the preparation of nanoparticulate metal oxides is described, in which dissolved metal salts are thermally decomposed in the presence of surfactants.
• the decomposition takes place under conditions under which the surfactants micelles, in addition, depending on the selected metal salt may require temperatures of several hundred degrees Celsius to achieve the decomposition.
• the process is therefore very complex in terms of apparatus and energy.
• WO 2004/052327 describes surface-modified nanoparticulate zinc oxides in which the surface modification comprises a coating with an organic acid.
• DE-A 10 2004 020 766 discloses surface-modified nanoparticulate metal oxides prepared in the presence of polyaspartic acid.
• EP 1455737 describes surface-modified nanoparticulate zinc oxides in which the surface modification comprises a coating with an oligo- or polyethylene glycol acid. Due to the acids used, these products are not suitable for cosmetic applications as they may only be poorly tolerated by the skin.
• Another object of the invention was the development of processes for the preparation of these surface-modified nanoparticulate particles and their aqueous suspensions and for their use.
• This object is achieved by surface-modified nanoparticulate particles of at least one metal oxide, metal hydroxide and / or metal oxide hydroxide which are precipitated from a solution in the presence of a nonionic dispersant.
• the invention thus provides a process for preparing surface-modified nanoparticulate particles of at least one metal oxide, metal hydroxide and / or metal oxide hydroxide, where the metal or metals are selected from the group consisting of aluminum, magnesium, cerium, iron, manganese, cobalt, Nickel, copper, titanium, zinc and zirconium, comprising the steps
• solution 1 Preparation of a solution of water and at least one metal salt of the abovementioned metals (solution 1) and a solution of water and at least one strong base (solution 2), wherein at least one of the two solutions 1 and 2 contains at least one nonionic dispersant whose chemical structure comprising between 2 and 10,000 -CH 2 CH 2 O- groups,
• step b) mixing the solutions 1 and 2 prepared in step a) at a temperature in the range from 0 to 120 ° C., wherein the surface-modified nanoparticulate ren particles and precipitate out to form an aqueous suspension of the solution,
• the metal oxide, metal hydroxide and metal oxide hydroxide may be both the anhydrous compounds and the corresponding hydrates.
• the metal salts in process step a) may be metal halides, acetates, sulfates or nitrates or hydrates of the salts mentioned.
• Preferred metal salts are halides, for example zinc chloride or titanium tetrachloride, acetates, for example zinc acetate dihydrate and nitrates, for example zinc nitrate.
• a particularly preferred metal salt is zinc chloride or zinc nitrate.
• the concentration of the metal salts in the solution 1 is generally in the range of 0.05 to 1 mol / l, preferably in the range of 0.1 to 0.5 mol / l, particularly preferably 0.2 to 0.4 mol / l
• the strong bases to be used according to the invention may generally be any substances capable of having a pH in aqueous solution of from about 8 to about 13, preferably from about 9 to about 12, depending on their concentration. 5 to produce. These may be, for example, metal oxides or hydroxides as well as ammonia or amines. Preference is given to using alkali metal hydroxides such as sodium or potassium hydroxide, alkaline earth metal hydroxides such as calcium hydroxide or ammonia. Particular preference is given to using sodium hydroxide, potassium hydroxide and ammonia. In a preferred embodiment of the invention, ammonia can also be formed by thermal decomposition of urea in situ during process steps a) and / or b).
• the concentration of the strong base in the solution 2 prepared in process step a) is generally selected so that in the solution 2 a Hydroxylionenkon- concentration in the range of 0.1 to 2 mol / l, preferably from 0.2 to 1 mol / l and more preferably from 0.4 to 0.8 mol / l.
• the hydroxyl ion concentration in solution 2 (c (OH-)) is chosen as a function of the concentration and the valence of the metal ions in the solution 1 (c (M n + )), so that they have the formula
• n • c (Mn + ) c (OH-) where c is a concentration and M n + is at least one metal ion of valency n.
• a solution 2 having a hydroxyl ion concentration of 0.4 mol / l is preferably used.
• the nonionic dispersants according to the invention are surface-active substances whose chemical structure comprises between 2 and 10,000 -CH 2 CH 2 O- groups, preferably between 3 and 200 -CH 2 CH 2 O- groups. These groups are formed, for example, by addition of a corresponding number of ethylene oxide molecules to hydroxyl- or carboxyl-containing substrates and usually form one or more contiguous ethylene glycol chains, the chemical structure of the formula - (- CH 2 CH 2 ⁇ -) n - with n from about 2 to about 80 corresponds.
• the nonionic dispersant used is at least one substance from one of the following groups:
• Alkylphenols having 8 to 15 carbon atoms in the alkyl group having 8 to 15 carbon atoms in the alkyl group
• Glycerol mono- and diesters sorbitol mono- and diesters and sorbitan mono- and
• Partial esters based on linear, branched, unsaturated or saturated fatty acids having 12 to 22 carbon atoms,
• Alkyl glucosides eg methyl glucoside, butyl glucoside, lauryl glucoside
• - polyglucosides eg cellulose
• At least one substance from one of the following groups is used as the nonionic dispersant:
• Non-ionic dispersants are under the brand name Cremophor ® (Fa. BASF Aktiengesellschaft) Avail- borrowed commercially.
• the ethylene oxide addition products can always also contain a small proportion of the above-listed free hydroxyl or carboxyl groups-containing substrates in technical quality. In general, this proportion is less than 20 wt .-%, preferably less than 5 wt .-%, based on the total amount of the dispersant.
• the concentration of the nonionic dispersants in the solutions 1 and / or 2 prepared in process step a) is generally in the range from 0.1 to 20 g / l, preferably from 1 to 10 g / l, particularly preferably from 1 to 5 5 g / l.
• a preferred embodiment of the process according to the invention is characterized in that the precipitation of the metal oxide, metal hydroxide and / or metal oxide hydroxide takes place in the presence of a nonionic dispersant which is obtained by reacting hydrogenated castor oil or fatty alcohols with about 35 to about 50 equivalents of ethylene oxide.
• a nonionic dispersant which is obtained by reacting hydrogenated castor oil or fatty alcohols with about 35 to about 50 equivalents of ethylene oxide.
• Cremophor ® CO 40 Fa. BASF Aktiengesellschft
• an addition product of 40 equivalents of ethylene oxide with hydrogenated castor oil or Cremophor ® A 25 is (Fa. BASF Aktiengesellschaft), an addition product of 25 equivalents of ethylene oxide with cetyl stearyl alcohol , used as a nonionic dispersant.
• the mixing of the two solutions 1 and 2 (aqueous metal salt solution and aqueous base solution) in process step b) takes place at a temperature in the range from 0 ° C. to 120 ° C., preferably in the range from 10 ° C. to 100 ° C., more preferably in the range from 15 ° C to 80 ° C.
• mixing may be carried out at a pH in the range of 3 to 13. In the case of zinc oxide, the pH during mixing is in the range of 7 to 11.
• the time for the mixing of the two solutions in process step b) according to the invention is in the range of 1 second to 6 hours, preferably in the range of 1 minute to 2 hours. In general, the mixing time is longer with discontinuous driving than with continuous driving.
• the mixing in process step b) can be carried out, for example, by combining an aqueous solution of a metal salt, for example zinc chloride or zinc nitrate, with an aqueous solution of a mixture of a nonionic dispersant and an alkali metal hydroxide or ammonium hydroxide, in particular sodium hydroxide.
• a metal salt for example zinc chloride or zinc nitrate
• an alkali metal hydroxide or ammonium hydroxide in particular sodium hydroxide.
• an aqueous solution of a mixture of a nonionic dispersant and a metal salt such as zinc chloride or zinc nitrate
• an alkali metal hydroxide or ammonium hydroxide especially sodium hydroxide.
• an aqueous solution of a mixture of a nonionic dispersant and a metal salt for example of zinc chloride or zinc nitrate
• an aqueous solution of a mixture of a nonionic dispersant and an alkali metal hydroxide or ammonium hydroxide, in particular sodium hydroxide can be combined.
• the mixing in process step b) is carried out by adding an aqueous solution of a mixture of a nonionic dispersant and an alkali metal hydroxide or ammonium hydroxide, in particular sodium hydroxide, to an aqueous solution of a metal salt, for example of zinc chloride or zinc nitrate, or Addition of an aqueous solution of an alkali metal hydroxide or ammonium hydroxide, in particular sodium hydroxide, to an aqueous solution of a mixture of a nonionic
• Dispersant and a metal salt such as zinc chloride or zinc nitrate.
• the surface-modified nanoparticulate particles are formed, which precipitate out of the solution to form an aqueous suspension.
• the mixing is carried out while stirring the mixture. After complete union of the two solutions 1 and 2, the stirring is preferably continued for a time between 30 minutes and 5 hours at a temperature in the range of 0 0 C to 120 0 C.
• a further preferred embodiment of the method according to the invention is characterized in that at least one of the method steps a) to d) is carried out continuously. be performed. In continuous operation, the process step b) is preferably carried out in a tubular reactor.
• the continuous process is carried out in the form that the mixing in step b) takes place in a first reaction space at a temperature T1 in which an aqueous solution 1 of at least one metal salt and an aqueous solution 2 of at least one strong base are introduced continuously at least one of the two solutions 1 and 2 contains at least one nonionic dispersant whose chemical structure comprises between 2 and 10,000 -CH 2 CH 2 O- groups from which the suspension formed is continuously removed and transferred to a second reaction space for temperature control at a temperature T2, wherein the surface-modified nanoparticulate particles form.
• the continuous process is carried out in such a way that the temperature T2 is higher than the temperature T1.
• the processes described in the introduction are particularly suitable for the preparation of surface-modified nanoparticulate particles of titanium dioxide and zinc oxide, in particular of zinc oxide.
• the precipitation of the surface-modified nanoparticulate particles of zinc oxide from an aqueous solution of zinc acetate, zinc chloride or zinc nitrate takes place at a pH in the range of 8 to 13 in the presence of a nonionic dispersant.
• a further advantageous embodiment of the process according to the invention is characterized in that the surface-modified nanoparticulate particles of a metal oxide, metal hydroxide and / or metal oxide hydroxide, in particular of zinc oxide, have a BET surface area in the range from 25 to 500 m 2 / g, preferably from 30 to 400 m 2 / g, more preferably 40 to 300 m 2 / g.
• the invention is based on the finding that, by surface modification of nanoparticulate metal oxides, metal hydroxides and / or metal oxide hydroxides with nonionic dispersants, long-term stability of dispersions of the surface-modified nanoparticulate metal oxides, in particular in cosmetic preparations, without undesired changes in the pH during storage of these preparations is achieved can be.
• the separation of the precipitated particles from the aqueous suspension in process step c) can be carried out in a manner known per se, for example by filtration or centrifugation. If necessary, prior to isolation of the precipitated particles, the aqueous dispersion may be applied by a membrane process such as nano-, ultra-,
• step b) It has proved to be advantageous to carry out the removal of the surface-modified nanoparticulate particles from the aqueous suspension obtained in step b) at a temperature in the range from 10 to 50 ° C., preferably at room temperature. It is therefore advantageous to optionally cool the aqueous suspension obtained in step b) to such a temperature.
• the resulting filter cake can be dried in a conventional manner, for example in a drying oven at temperatures between 40 and 100 0 C, preferably between 50 and 80 0 C under atmospheric pressure to constant weight.
• a further subject of the present invention are surface-modified nanoparticulate particles of at least one metal oxide, metal hydroxide and / or metal oxide hydroxide, where the metal or metals are selected from the group consisting of aluminum, magnesium, cerium, iron, manganese, cobalt, Nickel, copper, titanium, zinc and zirconium, and the surface modification comprises a coating with at least one nonionic dispersant, obtainable by the process described in the introduction.
• the present invention furthermore provides surface-modified nanoparticulate particles of at least one metal oxide, metal hydroxide and / or metal oxide hydroxide, in particular of zinc oxide, the surface modification comprising a coating with a nonionic dispersant having a BET surface area in the range from 25 to 500 m 2 / g, preferably 30 to 400 m 2 / g, particularly preferably 40 to 300 m 2 / g.
• the surface-modified nanoparticulate particles of at least one metal oxide, metal hydroxide and / or metal oxide hydroxide are coated with a nonionic dispersant which is an adduct of from 2 to 80 moles of ethylene oxide with linear fatty alcohols containing from 8 to 22 carbon atoms, alkylphenols with 8 to 15 carbon atoms in the alkyl group or castor oil and / or hydrogenated castor oil.
• a nonionic dispersant which is an adduct of from 2 to 80 moles of ethylene oxide with linear fatty alcohols containing from 8 to 22 carbon atoms, alkylphenols with 8 to 15 carbon atoms in the alkyl group or castor oil and / or hydrogenated castor oil.
• the surface-modified nanoparticulate particles have a diameter of from 10 to 200 nm. This is particularly advantageous since good redispersibility is ensured within this size distribution. According to a particularly preferred embodiment of the present invention, the surface-modified nanoparticulate particles have a diameter of 20 to 100 nm. This size range is particularly advantageous because, for example, after redispersion of such zinc oxide nanoparticles, the resulting suspensions are transparent and thus do not influence the coloring when added to cosmetic formulations. In addition, this results in the possibility for use in transparent films.
• Another object of the present invention is the use of surface-modified nanoparticulate particles of at least one metal oxide, metal hydroxide and / or metal oxide, in particular titanium dioxide or zinc oxide, which are prepared by the process according to the invention, as a UV protective agent in cosmetic sunscreen preparations, as a stabilizer in plastics and as an antimicrobial agent.
• the surface-modified nanoparticulate particles of at least one metal oxide, metal hydroxide and / or metal oxide hydroxide, in particular titanium dioxide or zinc oxide are redispersible in a liquid medium and form stable suspensions.
• the suspensions prepared from the zinc oxide according to the invention need not be redispersed before further processing, but can be processed directly.
• the surface-modified nanoparticulate particles of at least one metal oxide, metal hydroxide and / or metal oxide hydroxide are redispersible in polar organic solvents and form stable suspensions. This is particularly advantageous, since this uniform incorporation, for example, in plastics or films is possible.
• the surface-modified nanoparticulate particles of at least one metal oxide, metal hydroxide and / or metal oxide hydroxide are redispersible in water and form stable suspensions there. This is particularly advantageous, since this opens up the possibility of using the material according to the invention, for example in cosmetic formulations, wherein the omission of organic solvents represents a great advantage. Also conceivable are mixtures of water and polar organic solvents.
• a further subject of the present invention is therefore a process for preparing an aqueous suspension of surface-modified nanoparticulate particles of at least one metal oxide, metal hydroxide and / or metal oxide hydroxide, where the metal or metals are selected from the group consisting of aluminum, magnesium, cerium, iron, Manganese, cobalt, nickel, copper, titanium, zinc and zirconium, comprising the steps
• solution 1 Preparation of a solution of water and at least one metal salt of the abovementioned metals (solution 1) and a solution of water and at least one strong base (solution 2), wherein at least one of the two solutions 1 and 2 contains at least one nonionic dispersant whose chemical structure comprising between 2 and 10,000 -CH 2 CH 2 O- groups,
• step b) mixing the solutions 1 and 2 prepared in step a) at a temperature in the range from 0 to 120 ° C., whereby the surface-modified nanoparticulate particles are formed and precipitate out of the solution to form an aqueous suspension, and
• the aqueous suspension formed in step b) can be concentrated in process step c), for example if a higher solids content is desired.
• the concentration can be carried out in a manner known per se, for example by distilling off the water (at atmospheric pressure or at reduced pressure), filtering or centrifuging.
• Suitable by-products are primarily salts dissolved in water which are formed in the inventive reaction between the metal salt and the strong base in addition to the desired metal oxide, metal hydroxide and / or metal oxide hydroxide particles, for example sodium chloride, sodium nitrate or ammonium chloride.
• Such by-products can be largely removed from the aqueous suspension, for example by means of a membrane process such as nano-, ultra-, micro- or cross-flow filtration.
• a further preferred embodiment of the method according to the invention is characterized in that at least one of the method steps a) to c) are carried out continuously.
• a further subject of the present invention are aqueous suspensions of surface-modified nanoparticulate particles of at least one metal oxide, metal hydroxide and / or metal oxide hydroxide, wherein the metal or metals are selected from the group consisting of aluminum, magnesium, cerium, iron, manganese, cobalt, nickel, Copper, titanium, zinc and zirconium, and the surface modification comprises a coating with at least one nonionic dispersant obtainable by the method described above.
• the surface-modified nanoparticulate particles in the aqueous suspensions are coated with a nonionic dispersant which is an adduct of from 2 to 80 moles of ethylene oxide with linear fatty alcohols containing from 8 to 22 carbon atoms and alkylphenols with 8 to 15 carbon atoms in the alkyl group or castor oil and / or hydrogenated castor oil.
• a nonionic dispersant which is an adduct of from 2 to 80 moles of ethylene oxide with linear fatty alcohols containing from 8 to 22 carbon atoms and alkylphenols with 8 to 15 carbon atoms in the alkyl group or castor oil and / or hydrogenated castor oil.
• Another object of the present invention is the use of aqueous suspensions surface-modified nanoparticulate particles of at least one metal oxide, metal hydroxide and / or metal oxide, in particular titanium dioxide or zinc oxide, which are prepared by the process according to the invention, as UV protectants in cosmetic sunscreen preparations, as a stabilizer in synthetic materials and as an antimicrobial agent.
• Solution 1 contained 27.26 g of zinc chloride per liter and had a zinc ion concentration of 0.2 mol / l.
• Solution 1 contained 4 g / l of Cremophor ® CO 40th
• Solution 2 contained 16 g of sodium hydroxide per liter and thus had a hydroxyl ion concentration of 0.4 mol / l.
• a suspension flow of 0.96 l / min was pumped from the suspension obtained via a riser pipe by means of a gear pump (Gather Industrie GmbH, D-40822 Mettmann) and heated to a temperature in a downstream heat exchanger within 1 minute heated to 85 ° C.
• the suspension obtained then passed through a second heat exchanger, in which the suspension was kept at 85 ° C. for a further 30 seconds.
• the suspension subsequently passed through a third and fourth heat exchanger in succession, in which the suspension was cooled to room temperature within a further minute.
• the freshly prepared suspension was dissolved in a crossflow ultrafiltration
• the powder obtained had the absorption band characteristic of zinc oxide at about 350-360 nm.
• the X-ray diffraction of the powder showed only the diffraction reflections of hexagonal zinc oxide. From the half-width of the X-ray reflections a crystallite size was calculated, which lies between 16 nm [for the (102) -reflex] and 57 nm [for the (002) -reflex].
• the obtained powder had an average particle size of 50 to 100 nm.
• the freshly prepared suspension was thickened by the factor 15 in a crossflow ultrafiltration laboratory system (Sartorius, type SF Alpha, PES cassette, cut off 100 kD). Subsequent isolation of the solid powder was carried out using an ultracentrifuge (Sigma 3K30, 20,000 rpm, 40.700g) with subsequent drying at 50 0 C.
• the resulting powder In the UV-VIS spectrum, the resulting powder exhibited the absorption band characteristic of zinc oxide at about 350-360 nm. In line with this, the X-ray diffraction of the powder showed only the diffraction reflections of hexagonal zinc oxide. From the half-width of the X-ray reflections, the crystallite size was calculated to be between 16 nm [for the (102) reflection] and 57 nm [for the (002) reflection]. In the transmission electron microscopy (TEM), the obtained powder had an average particle size of 50 to 100 nm.
• TEM transmission electron microscopy
• Solution 1 contained 27.26 g of zinc chloride per liter and had a zinc ion concentration of 0.2 mol / l.
• the solution contained 1 4 g / l of Cremophor ® A 25th
• Solution 2 contained 16 g of sodium hydroxide per liter and thus had a hydroxyl ion concentration of 0.4 mol / l.
• a suspension flow of 0.96 l / min was pumped out of the suspension obtained via a riser pipe by means of a gear pump (Gather Industrie GmbH, D-40822 Mettmann) and discharged in a downstream Heat exchanger heated to a temperature of 85 ° C within 1 minute.
• the suspension obtained then passed through a second heat exchanger, in which the suspension was kept at 85 ° C. for a further 30 seconds.
• the suspension subsequently passed through a third and fourth heat exchanger in succession, in which the suspension was cooled to room temperature within a further minute.
• the freshly prepared suspension was thickened by the factor 15 in a crossflow ultrafiltration laboratory system (Sartorius, type SF Alpha, PES cassette, cut off 100 kD). Subsequent isolation of the solid powder was carried out using an ultracentrifuge (Sigma 3K30, 20,000 rpm, 40.700g) with subsequent drying at 50 0 C.
• the resulting powder In the UV-VIS spectrum, the resulting powder exhibited the absorption band characteristic of zinc oxide at about 350-360 nm. In line with this, the X-ray diffraction of the powder showed only the diffraction reflections of hexagonal zinc oxide. From the half-width of the X-ray reflections a crystallite size was calculated, which lies between about 15 nm [for the (102) -reflex] and about 60 nm [for the (002) -reflex]. In the transmission electron microscopy (TEM), the obtained powder had an average particle size of 50 to 100 nm.
• TEM transmission electron microscopy
• a suspension flow of 0.96 l / min was pumped out of the glass reactor via a riser pipe by means of a gear pump (Gather Industrie GmbH, D-40822 Mettmann) and within a minute to a temperature of 85 ° in a downstream heat exchanger C heated.
• the suspension obtained then passed through a second heat exchanger, in which the suspension was kept at 85 ° C. for a further 30 seconds.
• the suspension successively passed through a third and fourth heat exchanger, in which the suspension was cooled to room temperature within a further minute.
• the freshly prepared suspension was thickened by a factor of 15 in a crossflow ultrafiltration laboratory system (Sartorius, type SF Alpha, PES cassette, cut off 100 kD).
• Subsequent isolation of the solid powder was carried out using an ultracentrifuge (Sigma 3K30, 20,000 rpm, 40.700g) with subsequent drying at 50 0 C.
• the resulting powder In the UV-VI S spectrum, the resulting powder exhibited the characteristic absorption band for zinc oxide at about 350-360 nm. In line with this, the X-ray diffraction of the powder showed only the diffraction reflections of hexagonal zinc oxide. From the half-width of the X-ray reflections a crystallite size was calculated, which lies between about 15 nm [for the (102) -reflex] and about 60 nm [for the (002) -reflex]. In the transmission electron microscopy (TEM), the obtained powder had an average particle size of 50 to 100 nm.
• TEM transmission electron microscopy
• the X-ray diffraction of the powder showed only the diffraction reflections of hexagonal zinc oxide. From the half-width of the X-ray reflections, the crystallite size was calculated to be between 17 nm [for the (102) reflection] and 45 nm [for the (002) reflection]. In the transmission electron microscopy (TEM), the obtained powder had an average particle size of 40 to 80 nm.
• nanoparticulate zinc oxide prepared according to Example 1, for the preparation of a sunscreen lotions containing 5% by weight of zinc oxide
• phase A is heated to 80 0 C, then the phase B is added, the mixture is homogenized for 3 minutes.
• phase C is heated to 80 ° C and stirred into the mixture of phases A and B.
• the mixture is cooled to 40 0 C while stirring, then the phase D is added.
• the lotion is briefly posthumogenised.
• Solution 1 contained 54.52 g zinc chloride per liter and had a zinc ion concentration of 0.4 mol / l.
• Solution 1 contained 4 g / l of Cremophor ® CO 40th
• the solution 2 contained 32 g of sodium hydroxide per liter and thus had a hydroxyl ion concentration of 0.8 mol / l.
• the freshly prepared suspension was washed in a crossflow ultrafiltration laboratory equipment (Sartorius, type SF Alpha, PES cassette, cut off 100 kD) and thickened by a factor of 15. Subsequent isolation of the solid powder was carried out using an ultracentrifuge (Sorvall RC 6, Fa. Thermo Electron Corporation, 13000 rpm) with subsequent drying at 80 0 C.
• the powder obtained had the absorption band characteristic of zinc oxide at about 350-360 nm.
• the obtained powder had an average particle size of 50 to 100 nm.
• Solution 1 contained 54.52 g zinc chloride per liter and had a zinc ion concentration of 0.4 mol / l. Furthermore, the solution 1 still contained 8 g / l of Cremophor ® CO 40th
• the solution 2 contained 32 g of sodium hydroxide per liter and thus had a hydroxyl ion concentration of 0.8 mol / l.
• the freshly prepared suspension was washed in a crossflow ultrafiltration laboratory system (Sartorius, type SF Alpha, PES cassette, cut off 100 kD) and thickened by a factor of 15. Subsequent isolation of the solid powder was carried out using an ultracentrifuge (Sorvall RC 6, Fa. Thermo Electron Corporation, 13000 rpm) with subsequent drying at 80 0 C.
• the resulting powder In the UV-VIS spectrum, the resulting powder exhibited the absorption band characteristic of zinc oxide at about 350-360 nm. In the transmission electron microscopy (TEM), the obtained powder had an average particle size of 50 to 100 nm.
• TEM transmission electron microscopy
• Solution 2 contained 16 g of sodium hydroxide per liter and thus had a hydroxyl ion concentration of 0.4 mol / l.
• the freshly prepared suspension was washed in a crossflow ultrafiltration laboratory system (Sartorius, type SF Alpha, PES cassette, cut off 100 kD) and thickened by a factor of 15. Subsequent isolation of the solid powder was carried out using an ultracentrifuge (Sorvall RC 6, Fa. Thermo Electron Corporation, 13000 rpm) with subsequent drying at 80 0 C.
• the resulting powder In the UV-VIS spectrum, the resulting powder exhibited the absorption band characteristic of zinc oxide at about 350-360 nm. In the transmission electron microscopy (TEM), the obtained powder had an average particle size of 50 to 100 nm.
• TEM transmission electron microscopy
• Solution 1 contained 27.26 g of zinc chloride per liter and had a zinc ion concentration of 0.2 mol / l.
• Solution 1 contained 4 g / l of Cremophor ® CO 40th Solution 2 contained 16 g of sodium hydroxide per liter and thus had a hydroxyl ion concentration of 0.4 mol / l.
• the freshly prepared suspension was washed in a crossflow ultrafiltration laboratory equipment (Sartorius, type SF Alpha, PES cassette, cut off 100 kD) and thickened by a factor of 15. Subsequent isolation of the solid powder was carried out using an ultracentrifuge (Sorvall RC 6, Fa. Thermo Electron Corporation, 13000 rpm) with subsequent drying at 80 0 C.
• the powder obtained had the absorption band characteristic of zinc oxide at about 350-360 nm.
• the obtained powder had an average particle size of 50 to 100 nm.
• Solution 1 contained 27.26 g of zinc chloride per liter and had a zinc ion concentration of 0.2 mol / l. Furthermore, the solution 1 still contained 8 g / l of Cremophor ® CO 40th
• Solution 2 contained 16 g of sodium hydroxide per liter and thus had a hydroxyl ion concentration of 0.4 mol / l.
• the freshly prepared suspension was washed in a crossflow ultrafiltration laboratory equipment (Sartorius, type SF Alpha, PES cassette, cut off 100 kD) and thickened by a factor of 15. Subsequent isolation of the solid powder was carried out using an ultracentrifuge (Sorvall RC 6, Fa. Thermo Electron Corporation, 13000 rpm) with subsequent drying at 80 0 C.
• the resulting powder had in the UV-VI S-S pectrum the characteristic of zinc oxide absorption band at about 350 - 360 nm.
• the obtained powder had an average particle size of 50 to 100 nm.
• Solution 1 contained 54.52 g zinc chloride per liter and had a zinc ion concentration of 0.4 mol / l.
• the solution contained 1 or 2 g / l of Cremophor ® A 25th
• the solution 2 contained 32 g of sodium hydroxide per liter and thus had a Hydroxylio- nenkonzentration of 0.8 mol / l.
• the freshly prepared suspension was washed in a crossflow ultrafiltration laboratory system (Sartorius, type SF Alpha, PES cassette, cut off 100 kD) and thickened by a factor of 15. Subsequent isolation of the solid powder was carried out using an ultracentrifuge (Sorvall RC 6, Fa. Thermo Electron Corporation, 13000 rpm) with subsequent drying at 80 0 C.
• the powder obtained had the absorption band characteristic of zinc oxide at about 350-360 nm.
• the obtained powder had an average particle size of 50 to 100 nm.
• Solution 1 contained 54.52 g zinc chloride per liter and had a zinc ion concentration of 0.4 mol / l.
• the solution contained 1 4 g / l of Cremophor ® A 25th
• the solution 2 contained 32 g of sodium hydroxide per liter and thus had a hydroxyl ion concentration of 0.8 mol / l.
• the freshly prepared suspension was washed in a crossflow ultrafiltration laboratory system (Sartorius, type SF Alpha, PES cassette, cut off 100 kD) and thickened by a factor of 15. Subsequent isolation of the solid powder was carried out using an ultracentrifuge (Sorvall RC 6, Fa. Thermo Electron Corporation, 13000 rpm) with subsequent drying at 80 0 C.
• the powder obtained had the absorption band characteristic of zinc oxide at about 350-360 nm.
• the obtained powder had an average particle size of 50 to 100 nm.
• Solution 1 contained 54.52 g zinc chloride per liter and had a zinc ion concentration of 0.4 mol / l. Furthermore, the solution 1 still contained 8 g / l of Cremophor ® A 25th
• the solution 2 contained 32 g of sodium hydroxide per liter and thus had a Hydroxylio- nenkonzentration of 0.8 mol / l.
• the powder obtained had the absorption band characteristic of zinc oxide at about 350-360 nm.
• the obtained powder had an average particle size of 50 to 100 nm.

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• 2007
  • 2007-10-10 WO PCT/EP2007/060778 patent/WO2008043790A2/de active Application Filing
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