EP1945701A1 - Nanopartikuläre zubereitung und verfahren zu ihrer erwärmung - Google Patents
Nanopartikuläre zubereitung und verfahren zu ihrer erwärmungInfo
- Publication number
- EP1945701A1 EP1945701A1 EP06828920A EP06828920A EP1945701A1 EP 1945701 A1 EP1945701 A1 EP 1945701A1 EP 06828920 A EP06828920 A EP 06828920A EP 06828920 A EP06828920 A EP 06828920A EP 1945701 A1 EP1945701 A1 EP 1945701A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- particles
- preparation
- temperature
- nanoparticulate
- range
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G49/00—Compounds of iron
- C01G49/009—Compounds containing, besides iron, two or more other elements, with the exception of oxygen or hydrogen
-
- 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
- C01G49/00—Compounds of iron
- C01G49/0018—Mixed oxides or hydroxides
- C01G49/0072—Mixed oxides or hydroxides containing manganese
-
- 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
- C09C1/22—Compounds of iron
-
- 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
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2006/00—Physical properties of inorganic compounds
- C01P2006/42—Magnetic properties
-
- 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
- C08K3/00—Use of inorganic substances as compounding ingredients
- C08K3/18—Oxygen-containing compounds, e.g. metal carbonyls
- C08K3/20—Oxides; Hydroxides
- C08K3/22—Oxides; Hydroxides of metals
-
- 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
- C08K7/00—Use of ingredients characterised by shape
Definitions
- the invention relates to a nanoparticulate preparation which comprises a coherent phase and at least one particulate phase of superparamagnetic, nanoscale particles having a volume-average particle diameter in the range from 2 to 100 nm dispersed therein, and a method for heating a corresponding nanoparticulate preparation to different temperatures.
- ferrites From WO 03/054102 A1 ferrites are known. These ferrites have a stoichiometry in which
- M a is selected from Mn, Co, Ni, Mg, Ca, Cu, Zn, Y and V
- M b is selected from Zn and Cd, x is 0.05 to 0.95, preferably 0.1 to 0.8, y is 0 to 0.95, and the sum of x and y is at most 1.
- ferrites can be heated under the conditions described there and in DE 100 37 883 A1 with the simultaneous use of microwave radiation having a frequency in the range of 1 to 300 GHz and a magnetic constant field with a field strength in the range of 0.001 to 10 Tesla.
- the microwave radiation causes in conjunction with the DC magnetic field in the substrate embedded in the particles the phenomenon of ferromagnetic resonance (FMR), as indicated in paragraph [0015] to paragraph [0027] of DE 100 37 883 A1, by the energy input from the microwave radiation into the particles leads to the actual heating of the preparation.
- FMR ferromagnetic resonance
- the application of a DC magnetic field serves to set or optimize the resonance frequency, as described on page 16 of WO 03/054102 A1 or in paragraph [0023] of DE 100 37 883 A1.
- nanoscale particles Preparations of particles with particle sizes in the nanometer range (nanoscale particles) have found application in many fields of technology. This is especially true for dispersions containing particles with magnetic, ferroelectric or piezoelectric Contain properties that can be heated under the action of magnetic, electrical or electromagnetic alternating fields. These serve, for example, for the production of adhesives and sealants which harden as a result of the heating induced by the application of alternating magnetic, electric or electromagnetic fields or in which an existing adhesive bond is separated. Such adhesives and sealants are used in many industries, especially in the metalworking industry, such.
- DE-A 199 23 625 describes a process for the preparation of redispersible metal oxides or metal hydroxides having a volume-weighted average crystallite size in the range of 1 to 20 nm, which are particularly suitable for so-called magnetic fluids (ferrofluids).
- DE-A 199 24 138 describes adhesive compositions which contain nanoscale particles with ferromagnetic, ferrimagnetic, superparamagnetic or piezoelectric properties in the binder system and which are suitable for producing releasable adhesive bonds.
- the adhesive bonds can be heated so high under the action of electromagnetic radiation that a slight solution (detackification) is possible.
- WO 01/30932 describes a method for the adhesive separation of adhesive bonds, wherein the adhesive composite comprises a thermally softenable thermoplastic or heat-cleavable thermosetting adhesive layer and a primer layer, wherein the primer layer contains nanoscale particles which can be heated by electromagnetic alternating fields.
- WO-A 01/28771 describes a microwave radiation curable composition
- a microwave radiation curable composition comprising particles capable of microwave absorption with a curie
- the temperature which is higher than the curing temperature of the composition contains, for example, the particles capable of microwave absorption may be ferrites.
- EP-A-0 498 998 describes a method for microwave heating a polymer material to a predetermined temperature, the polymer material containing dispersed ferromagnetic particles having a Curie temperature corresponding to the temperature desired by the heating.
- the particle diameter of the ferromagnetic material is in a range of 1 to 100 nm and the Curie temperature in a range of 50 to 700 0 C.
- the desired heating temperature may be, for example, the curing or melting temperature of the polymer material or for activation act temperature required a cleavage reaction,
- WO 01/14490 describes a method for bonding substrates with hotmelt adhesives, wherein these are used in combination with a microwaved (MW) activatable primer.
- MW microwaved
- the temperature for curing the adhesive is usually smaller than the temperature for detackifying or softening the adhesive.
- the adhesives known from the above prior art have nanoparticles, which are in particular ferrites. These ferrites, as stated above, allow the adhesives to be increased by microwave radiation and applying a DC magnetic field to a temperature limited by the Curie temperature. Although the ferrites provide sufficient energy absorption during curing, they are designed to be intrinsic Temperature limitation (Curie temperature) is effective to prevent overheating during curing, so that the same ferrites are not usable as an energy absorber for a higher temperature during detackifying.
- intrinsic Temperature limitation Cosmetic temperature
- a possible variant would be to use two different ferrites, which require a different bias by the magnetic DC field to achieve maximum energy absorption.
- One of the two ferrites would have a relatively low, but the other a significantly higher limit or end temperature.
- bias bias
- the adjustment of the different temperatures could be carried out by working with a correspondingly lower radiant power during bonding than during later removal.
- the end temperature would no longer be determined by the intrinsic temperature limitation of the ferrites, at least during bonding, but would result from the heat balance between the microwave absorption and the heat dissipation into the environment.
- the temperature-limiting effect of the ferrite would thus be dispensed with here.
- this process would be slower because the cure temperature would not reach so fast as the radiant power would be reduced.
- the object of the invention is to provide a nanoparticulate preparation and a method which makes it possible to heat the corresponding nanoparticulate preparation to different temperatures in a simple manner.
- the method should allow the curing (sticking) and subsequent softening (detackifying) of adhesive compositions.
- a particularly steep rise in temperature is achieved during the first few seconds of the irradiation process, so that particularly short cycle times during bonding are possible in a production.
- a high limit temperature is selected, then the absolute power of the ferrite reaches a maximum only at a fairly high temperature, so that the then very high heat losses are compensated by the heat dissipation.
- the system is still not without complete temperature limitation, since all at the latest at the Curie temperature of the ferrite, the microwave absorption decreases again.
- Gluing and detacking can be carried out in accordance with the same microwave system, for which only the bias must be changed in each case. If the pre-magnetization generated by permanent magnets, so only these magnets must be replaced. In systems using electromagnets, even only a change in the exciting current of the coil of the electromagnet is sufficient.
- the particles are selected from at least one electrically neutral ferrite of the general formula (M a 1-xy M b x FC y) 11 Fe 2 111 O 4 , wherein
- M a is selected from Mn, Co, Ni, Mg, Ca, Cu, Zn, Y and V
- M b is selected from Zn and Cd, x is 0.05 to 0.95, preferably 0.1 to 0.8, y is 0 to 0.95, and the sum of x and y is at most 1. These have proven to be particularly suitable.
- the particles used preferably have a temperature coefficient of the field-shift effect with a sign-independent value ⁇ greater than 0.05 mT / ° C, in particular greater than 0.10 mT / ° C, particularly preferably greater than 0.15 mT / ° C.
- ⁇ temperature coefficient of the field-shift effect with a sign-independent value ⁇ greater than 0.05 mT / ° C, in particular greater than 0.10 mT / ° C, particularly preferably greater than 0.15 mT / ° C.
- f eg 2.45 GHz
- y 28 GHz / T the gyromagnetic constant
- B ext the strength of the bias field
- B 1n the internal magnetic field defined by the composition of the ferrite
- the application of the DC magnetic field serves only to adjust or optimize the resonance frequency of the particle or ferrite.
- the required bias field can be set to satisfy Equation (1) for room temperature (20 ° C.):
- the magnetic field is usually higher when detackifying than when gluing.
- Equation (1) is no longer satisfied and MW absorption continues to decrease with increasing temperature. This results in a temperature-limiting effect of the particles used according to the invention or of the preferably used ferrite, which is also independent of the Curie temperature.
- C d is the volume fraction of the ferrite in the adhesive or polymer (C VO ⁇ ⁇ 0.1);
- ⁇ B is the ferromagnetic resonance (FMR) linewidth of the ferrite.
- the temperature dependence of M was referred to in WO 03/054102 A1 as the essential mechanism for the intrinsic temperature limitation.
- T 0 is the temperature at which the internal magnetic field B in the particle (ferrite) is specified (eg room temperature); ⁇ is the temperature coefficient of the field shift effect according to Eq. (3) and Y is the gyromagnetic constant.
- the preparation can be heated independently of the energy introduced by the microwave radiation only up to a maximum temperature independent of the Curie temperature, using mixed oxides with divalent metals selected as nanoscale particles such that the maximum temperature correlated with the field strength of the magnetic DC field, that is adjustable.
- Nanoscale particles for the purposes of the present application are particles having a volume-average particle diameter of at most 100 nm.
- a preferred particle size range is 4 to 50 nm, in particular 5 to 30 nm and particularly preferably 6 to 15 nm.
- Such particles are characterized by a high degree of uniformity
- the size of the particles is preferably determined by the UPA method (Ultrafine Particle Analyzer), eg by the laser light scattering method.
- a suitable method for producing superparamagnetic nanoscale particles which can be used according to the invention consists in the precipitation from acidic aqueous metal salt solutions by addition of a base.
- a base for example, optionally heated, aqueous hydrochloric acid solutions of metal salts for precipitation with a suitable amount of a heated base can be added.
- the temperature is at the alkaline precipitation in a range of 20 to 100 0 C, particularly preferably 25 to 95 0 C and in particular 60 to 90 0 C.
- the particles used are preferably surface-modified or surface-coated.
- the particles preferably have on at least part of their surface a single- or multi-layer coating which contains at least one compound having ionogenic, ionic and / or nonionic surface-active groups.
- the compounds having surface-active groups are preferably selected from the salts of strong inorganic acids, e.g.
- Nitrates and perchlorates saturated and unsaturated fatty acids such as palmitic acid, margaric acid, stearic acid, isostearic acid, nonadecanoic acid, lignoceric acid, palmitoleic acid, oleic acid, linoleic acid, linolenic acid and elaosteric acid, quaternary ammonium compounds such as tetraalkylammonium hydroxides, e.g. Tetramethylammonium hydroxide, silanes such as alkyltrialkoxysilanes and mixtures thereof.
- DE-A-197 26 282 describes the surface modification of nanoscale particles with at least two shells surrounding the particles.
- WO 97/38058 describes the preparation of nanoscale particles which have been surface-modified with silanes.
- the proportion of surface modifier is generally 1 to 50, preferably 2 to 40 and especially 10 to 30, percent by weight, based on the weight of the particles used.
- the coherent phase of the nanoparticulate preparations according to the invention is preferably selected from water, organic solvents, polymerizable monomers, polymers and mixtures thereof.
- Suitable organic dispersants are, for example, selected from oils, fats, waxes, esters of C with mono-, di- or trihydric alcohols, saturated acyclic and cyclic hydrocarbons, fatty acids, low molecular weight alcohols, fatty alcohols and mixtures thereof.
- These include, for example, paraffin and paraffin oils, mineral oils, linear saturated hydrocarbons having usually more than 8 carbon atoms, such as tetradecane, hexadecane, octadecane, etc., cyclic hydrocarbons, such as cyclohexane and decahydronaphthalene, waxes, esters of fatty acids, silicone oils, etc.
- Preferred are e.g. As linear and cyclic
- Polymerizable monomers and polymers suitable as the coherent phase are mentioned below in the adhesive compositions.
- the rheological properties can be advantageously adjusted in a wide range depending on the type and amount of the dispersant.
- preparations can be produced which have a liquid to gel-like consistency.
- Gel-like consistency shows agents which have a higher viscosity than liquids and which are self-supporting, that is to say retain the shape given to them without a shape-stabilizing coating
- the viscosity of such preparations is, for example, in the range from about 1 to 60,000 mPas.
- the preparations used on the basis of liquid dispersants according to the invention are generally redispersible, d. H. the dispersed particles can be recovered by drying the preparation and then redispersed, substantially without deteriorating the dispersibility and the magnetic and alternating magnetic field absorbing ability.
- the proportion of the nanoscale particles is preferably 1 to 70, in particular 2 to 35 and especially 3 to 10 percent by weight, based on the total weight of the nanoparticulate preparation. Due to the very good ability of the preparations used for energy absorption by absorption of microwaves (MW) according to the invention, the proportion of dispersed particles required to absorb a certain amount of energy can be significantly reduced in comparison with particulate preparations from the prior art.
- the preparation used according to the invention is an adhesive composition.
- the coherent phase of adhesive compositions comprises at least one polymer suitable for use in adhesives and / or at least one polymerizable one VZ
- thermoplastically softenable adhesives based on ethylene-vinyl acetate copolymers, polybutenes, styrene-isoprene-styrene or styrene-butadiene-styrene copolymers, thermoplastic elastomers, amorphous polyolefins, linear, thermoplastic polyurethanes, copolyesters, polyamide resins, polyamide / EVA copolymers, polyaminoamides based on dimer fatty acids, polyester amides or polyether amides.
- the coherent phase of thermally activatable chemically reactive adhesives generally contains one or more components that are susceptible to polyreaction. These include, for example, adhesives containing polyisocyanates with capped thermally activatable isocyanate groups and a component having isocyanate-reactive groups, such as. As a polyol.
- an adhesive composition of a thermosetting polymerization adhesive is preferably used, which polymerizes in a temperature range between 40 and 140 0 C and above 140 0 C by a glass phase transition from solid to a softened state or at temperatures above 140 0 C by thermal Damage to the polymer matrix undergoes a significant loss of strength. Examples include the adhesives Ashland Pliogripp 7770, Dow Betamate, Lord Fusor 380/383.
- thermosetting is understood to mean the heat-initiated curing of an adhesive composition which usually employs a separately present crosslinking agent. This is usually referred to by experts as extraneous networking. If the crosslinking agents are already incorporated into the adhesive composition, this is also referred to as self-crosslinking. According to the invention, the crosslinking is advantageous and is therefore preferred.
- actinic radiation is electromagnetic radiation and corpuscular radiation into consideration.
- the electromagnetic radiation includes near infrared (NIR), visible light, ultraviolet radiation, x-rays and gamma rays, particularly ultraviolet radiation.
- the corpuscular radiation comprises electron radiation, alpha radiation, proton radiation and neutron radiation, in particular electron radiation.
- Materials curable with actinic radiation include, as is known, radiation-curable low molecular weight, oligomeric and / or polymeric compounds, preferably radiation-curable binders, in particular based on ethylenically unsaturated prepolymers and / or ethylenically unsaturated oligomers, optionally one or more reactive diluents and optionally one or more photoinitiators.
- Suitable radiation-curable binders are (meth) acryl-functional (meth) acrylic copolymers, polyether acrylates, polyester acrylates, unsaturated polyesters, Epoxy acrylates, urethane acrylates, amino acrylates, melamine acrylates, silicone acrylates and the corresponding methacrylates. Binders which are free of aromatic structural units are preferably used.
- ferrites are still suitable as particles in which up to 10% of the trivalent iron ions are replaced by other trivalent "rare earths” or Al, Cr, etc.
- Such ferrites have, for example, the following formula: (M a 1-xy M b x Fe y ) "(Fe 2- Z M C Z )" 1 O 4 .
- z ⁇ 0.2 and M c is selected from the group consisting of Al, Cr and the rare earths (Ce, Lu, in particular Gd) or combinations thereof.
- the elements scandium (atomic number 21), yttrium (39) and lanthanum (57) and the 14 lanthanum elements cerium (58), praseodymium (59), neodymium (60), promethium (61), samarium (62 ), Europium (63), gadolinium (64), terbium (65), dysprosium (66), holmium (67), erbium (68), thulium (69), ytterbium (70) and lutetium (71).
- the alternating electromagnetic field of a microwave radiation having a frequency in the range of about 0.1 to 300 GHz is used.
- the preparation is simultaneously exposed to a DC magnetic field whose field strength is approximately in the range of 0.001 to 10 Tesla.
- the frequency of the microwave radiation used is preferably in a range of 100 MHz to 25 GHz.
- the particles preferably used have a linewidth of the FMR absorption maximum ⁇ B of less than 100 mT, in particular less than 50 mT (compare equation (6)).
- the line width is small enough to be heated particularly specifically even when the field strength of the DC magnetic field changes.
- the superparamagnetic, nanoscale particles used in accordance with the invention make it possible to achieve a sharp resonance frequency in the preparations depending on the applied field strength and not, as in the case of particulate preparations from the prior art, a mixture of widely distributed frequencies.
- the microwave absorption frequencies of the individual nanoparticles are never completely equal, so that only that fraction of the dispersed particles always absorbs microwave energy whose absorption frequency actually corresponds to a radiated frequency. All other particles are inactive, which leads to insufficient utilization of the registered energy.
- Particularly preferably used particles have an internal magnetization B int at 20 0 C of greater than 50 mT, in particular greater than 250 mT. At 120 ° C., the internal magnetization B int should be greater than 30 mT, in particular greater than 100 mT. Thus, large field-shift effect can be achieved since ⁇ is dependent on B int (see equation 2), so that considerable differences between the adjustable temperatures are made possible.
- the process according to the invention is very particularly preferably suitable for bonding and detacking of substrates, at least one adhesive being used for bonding i) to at least one part of a surface
- Substrates applies the preparation whose coherent phase at least one
- the adhesive bond can be produced by targeted heating of the adhesive composition (bond-on-command) by introduction of energy in the form of microwave radiation, for example by a chemical reaction between suitable functional groups of the adhesive composition, as described above.
- a curing initiating component for.
- the curing triggering components can be dispersed, for example in the form of microcapsules in the adhesive composition.
- the irradiation can cause a certain heating, which leads to an opening of the microcapsules and release of the components contained. According to this method, it is possible to cure the adhesive composition with a very low energy input since it is not necessary to heat the entire adhesive composition.
- this is for heating to a second temperature, which is higher than the first temperature, a microwave radiation having a frequency in the range of 0.1 to 300 GHz and a DC magnetic field with a second field strength in Range from 0.001 to 10 Tesla, which is higher than the first field strength under Hi), wherein the adhesive bond dissolves at the second higher temperature, so that, optionally under mechanical stress, the bonded substrates can be separated from each other.
- This release of the adhesive bond by deliberate heating of the cured adhesive composition (disbond-on-command) by means of entry of energy in the form of microwaves can be based, for example, on a reversible or irreversible softening of the adhesive bond.
- the adhesive used may be a hot melt adhesive which reversibly softens as a result of the heating caused by the action of the radiation. This reversible softening can then be used both for targeted production as well as for targeted release of an adhesive bond (see above).
- thermoplastic adhesive bonds the heating can take place above the softening point and, in the case of thermosetting adhesive bonds, to one Temperature which causes a cleavage.
- the set adhesive may contain thermally labile bonds that are cleaved as a result of the heating caused.
- the release of the adhesive bond can be carried out in such adhesives without the action of chemicals and under conditions under which the assembled substrates are not significantly heated and thus thermally damaged.
- the adhesive composition may also comprise cleavage reagents in thermally activatable, for example encapsulated, crystalline, chemically blocked, topologically or sterically inactivated or kinetically inhibited form (see above).
- the components causing the cleavage are present, for example, in the form of microcapsules, which are additionally dispersed in the adhesive composition.
- the heating can be limited to just these capsules, so that the energy required energy consumption can be greatly reduced compared with a homogeneous distribution throughout the composition.
- the product was sedimented after precipitation in the reactor with cooling, the supernatant water (10 L) sucked off and the sediment slurried with 9L water.
- the sedimentation, suction and washing was repeated several times until the pH of the wash water was about 10 and a colloidal suspension of nanoferrite particles in the residual liquor, which can no longer be separated by sedimentation.
- the suspension was then heated to 80 0 C and treated at 80 0 C with 1046g of oleic acid under increased agitation.
- step (a) 4.99 g of manganese-zinc ferrite from step (a) were stirred into 25.65 g of toluene until a homogeneous dispersion is formed. To this was slowly added 15.11 g of finely powdered calcium carbonate (anhydrous). The toluene was then first evaporated in air, then under vacuum (100 mbar), so that finally a solid granules was obtained.
- the shell is mounted on the face of a rectangular waveguide (standard R26, 43 x 86 mm cross-section) of a MW system (Mügge, MX 2000 series, with R26 waveguide connection), so that when the granules are heated by the MW radiation a controlled heat flow from the granules through the bottom of the Teflon shell in the waveguide is possible.
- This consists of cast aluminum and has 20 0 C.
- the measuring tip of a glass fiber thermometer is inserted into the granules (Ipitek Lumitherm 500).
- the sample is preheated at a MW radiation power of 240 W MW at 2.45 GHz and without premagnetization, after about 2 minutes a temperature equilibrium at about 100 ° C. in the granules established.
- This heating is based primarily on the dielectric losses of the microwave radiation in the organic components of the granules and only a small part on the energy absorption of the ferrite.
- the specific MW absorption of the ferrites is activated.
- the magnitude of the applied magnetic field B ext is between 48 mT and 90 mT, depending on the strength of the internal field B int of the ferrite material.
- the temperature in the granules continues to rise (FIG. 1).
- the MW absorption at the 48 mT pre-magnetized measurement above 150 0 C decreases sharply, so that 160 0 C are never exceeded.
- the temperature increases by 30 0 C higher.
- FIG. 1 shows the heating and cooling curve of the ferrite granules at different premagnetizations.
- a ferrite of composition Mn 018 Zn 012 Fe 2 O 4 surface-coated with oleic acid was exposed to MW irradiation (as above) at different temperatures and biasing.
- Figure 2 shows the MW energy absorption per gram of ferrite for different bias strengths as a function of temperature (bias: 1 A equals 12 mT).
- bias 1 A equals 12 mT.
- the MW absorption decreases with low bias as a function of temperature (at 54 mT: decrease by 0.3 units between 120 and 180 0 C), on the other hand, with strong premagnetization it increases (at 84 mT: increase by 0.6 units between 120 and 180 ° C)).
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Inorganic Chemistry (AREA)
- Nanotechnology (AREA)
- Physics & Mathematics (AREA)
- Composite Materials (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Materials Engineering (AREA)
- Crystallography & Structural Chemistry (AREA)
- Adhesives Or Adhesive Processes (AREA)
Abstract
Description
Claims
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE102005053657 | 2005-11-10 | ||
PCT/EP2006/010575 WO2007054241A1 (de) | 2005-11-10 | 2006-11-03 | Nanopartikuläre zubereitung und verfahren zu ihrer erwärmung |
Publications (1)
Publication Number | Publication Date |
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EP1945701A1 true EP1945701A1 (de) | 2008-07-23 |
Family
ID=37697973
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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EP06828920A Withdrawn EP1945701A1 (de) | 2005-11-10 | 2006-11-03 | Nanopartikuläre zubereitung und verfahren zu ihrer erwärmung |
Country Status (2)
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EP (1) | EP1945701A1 (de) |
WO (1) | WO2007054241A1 (de) |
Families Citing this family (1)
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DE102018218050A1 (de) * | 2018-10-22 | 2020-04-23 | Robert Bosch Gmbh | Verfahren zur Herstellung einer Baugruppe, einen Batteriedeckel und ein Batterieterminal umfassend |
Family Cites Families (5)
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DE19800294A1 (de) * | 1998-01-07 | 1999-07-08 | Mueller Schulte Detlef Dr | Induktiv aufheizbare magnetische Polymerpartikel sowie Verfahren zur Herstellung und Verwendung derselben |
DE10163399A1 (de) * | 2001-12-21 | 2003-07-10 | Sustech Gmbh & Co Kg | Nanopartikuläre Zubereitung |
DE10258959A1 (de) * | 2002-12-16 | 2004-07-08 | Sustech Gmbh & Co. Kg | Kunststofffolie |
DE102004004764A1 (de) * | 2004-01-29 | 2005-09-01 | Sustech Gmbh & Co. Kg | Interferenzfreie Mikrowellen-Bestrahlung zur Härtung von Klebnähten |
DE102005049136A1 (de) * | 2004-12-01 | 2006-06-08 | Degussa Ag | Zubereitung, enthaltend ein polymerisierbares Monomer und/oder ein Polymer und darin dispergiert ein superparamagnetisches Pulver |
-
2006
- 2006-11-03 EP EP06828920A patent/EP1945701A1/de not_active Withdrawn
- 2006-11-03 WO PCT/EP2006/010575 patent/WO2007054241A1/de active Application Filing
Non-Patent Citations (1)
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See references of WO2007054241A1 * |
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WO2007054241A1 (de) | 2007-05-18 |
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