MX2008004733A - Plastic composite moulded bodies obtainable by welding in an electromagnetic alternating field - Google Patents

Abstract

The invention relates to plastic composite moulded bodies which are obtainable by welding in an electromagnetic alternating field and whose welding assembling is carried out with the aid of a plastic material containing nanoscale magnetic oxide particles consisting of aggregated primary particles, wherein said primary particles are formed by magnetic metal-oxide domains whose diameter ranges from 2 to 100 nm in a non-magnetic metal-oxide or metalloid-oxide matrix.

Description

Molds of plastic compounds that can be obtained through welding in an alternating electromagnetic field The invention relates to molds of plastic compounds that can be obtained through welding in an alternating electromagnetic field, where the welding is achieved with the help of a plastic material which comprises nano-scale magnetic oxide particles. Plastic molds can agglomerate through a very wide variety of plastic welding processes. The family processes are, welding by heated tool, welding by heated coil, welding by ultrasound, welding by vibration, welding through laser transmission, welding by rotation and welding by high frequency. The joining processes by means of an alternating electromagnetic field or by means of microwaves are used less frequently and are still considered as specialized processes. In the case of laser transmission welding, at least the mold facing the radiation source must be transparent to the laser beam, thus restricting the pigmentation and coloring of the plastic materials that may be used. In contrast, the restrictions regarding dyes do not arise in the case of welding in a automated electromagnetic field. Welding with electromagnetic radiation (induction welding) usually requires a welding aid that is activated magnetically by itself or through correct ingredients. The welding aid is heated by hysteresis losses and / or eddy current losses and energy input here during inductive heating is about 1500 times higher than when conducted heat is used. The phases of induction welding include melting, melting of melts and consolidation, and the welding process can be carried out continuously or by batches. The welding aid can, for example, be placed in the form of sheets or sheets between the joined areas of the molds to be joined. Magnetic activation is often generated through metal inclusions, but this complicates the production process of the plastic parts that will be joined and these inclusions are sometimes undesirable in the subsequent operations of the product. Welding aids with ferromagnetic particulate fillers are relatively expensive and exhibit poor effectiveness factors and this has prevented the process from being one of the well established bonding processes. Therefore, it is an objective of the invention develop plastic materials that are activated magnetically through correct additives, thus providing a welding facility equal to that of the alternating electromagnetic field. These materials must have the ability to be used either in the form of integral constituents of the plastic molds to be joined or in the form of additional welding aids. DE-A-19924138 claims an adhesive composition comprising, inter alia, nano-scale particles with super-paramagnetic properties. DE-A-10163399 describes a preparation of nanoparticles having a coherent phase and at least one particle phase composed of super-paramagnetic nano-scale particles dispersed therein. Preference is given here to the preparations in the form of an adhesive composition. The compositions of DE-A-19923138 and DE-A-10163399 can be heated in an alternating electromagnetic field. The particles used not only in DE-A-19924138 but also in DE-A-10163399 have been preferably surface modified or surface coated, in order to inhibit the agglomeration or segregation of nano-scale particles and / or in order to provide a good dispersion of the particle phase in the coherent phase. A disadvantage here is that the substances used for coating the surface or for modifying the surface can be released in particular on exposure to high temperatures and / or high levels of mechanical action. One consequence is that nano-scale particles can agglomerate or segregate, thus losing its super-paramagnetic properties. The rheological properties of the nanoparticle preparation according to DE-A-10163399 or of the adhesive composition according to DE-A-19924138 can be adjusted widely by the nature and amount of the dispersion medium. However, it is impossible, or only possible up to a certain limit, to adjust the rheology of the preparation through the nano-scale, super-paramagnetic particles by themselves, since the super-paramagnetic properties are associated with certain particle sizes. . The particles almost entirely take the form of the primary particles in the preparation, and therefore the only possible method to adjust the rheology, for example, is to thicken, while involving the variation in the content of super-paramagnetic particles. The earlier patent application DE 102004057830 of 01.12.2004, which was not published on the first date of Priority of the present invention, and the entire content of which is incorporated herein by reference, discloses an adhesive composition comprising a polymerizable monomer and / or a polymer therein that is composed of aggregated primary particles, wherein the Primary particles are composed of magnetic metal oxide domains whose diameter is from 2 to 100 nm in a non-magnetic metal oxide matrix or a non-magnetic metalloid oxide matrix. Surprisingly, it has been found that nano-scale magnetic oxide particles are suitable additives for plastic materials, to provide ease of welding thereof in an alternating electromagnetic field. Correspondingly, the invention provides the use of magnetic oxide particles at nano-scale as additives in plastic materials, to provide ease of welding thereof in the alternating electromagnetic field. The invention also provides a process for the production of plastic composite molds by welding in an alternating electromagnetic field, in which welding is achieved with the aid of a plastic material comprising particles of magnetic oxide at nano-scale. The invention in particular provides welds of plastic composite that are obtained through welding in an alternating electromagnetic field, where welding is achieved with the help of a plastic material comprising nano-scale magnetic oxide particles. The magnetic oxide particles are very substantial in the homogeneous dispersion within the inventive plastic materials and in particular they are in non-agglomerated form. Within the plastic materials, these particles are particularly stable to temperature variation and do not exhibit agglomeration even at high temperatures. Moreover, it is possible to control the rheology of the compositions very substantially independently of the content of these particles. For the purposes of the present invention, the term aggregate indicates three-dimensional structures of the adherent primary particles. Binding between a plurality of aggregates can give agglomerates. These agglomerates can be easily separated again by means of a mechanical action, for example during extrusion processes. In contrast to this, it is generally not possible to separate the aggregates to give primary particles. The diameter of the aggregates of the nano-scale magnetic oxide particles may preferably be greater than 100 nm and less than 1 μp. It is preferred that the diameter of the aggregates of magnetic oxide particles at nano-scale, at least in one spatial direction, is not greater than 250 nm. Figure 1 illustrates this situation, in which the diameter of two branches of an aggregate is 80 nm and 135 nm. The term domain indicates regions spatially separated from each other in a matrix. The diameter of the domains of the magnetic particles at nano-scale is from 2 to 100 nm. The term nano-scale magnetic oxide particles in particular indicates super-paramagnetic particles. The domains also have zones that are not magnetic, but these then do not make contributions to the magnetic properties of the particles. There may also be present magnetic domains that, due to their size, do not exhibit any super-paramagnetism, and induce a remanence. This leads to an increase in volume-specific saturation magnetization. According to the present invention, the number of super-magnetic domains present in the super-paramagnetic particles is such that the inventive plastic materials can be heated to the melting point by means of an electric, magnetic or alternate electromagnetic The surrounding matrix may entirely or only partially surround the domains of the super-paramagnetic particles. The term "partially encircling" indicates that the individual domains may be protruding from the surface of an aggregate. The super-magnetic domains of the particles are not always agglomerated. The domains may be comprised of one or more metal oxides. The magnetic domains may preferably comprise iron oxides, cobalt, nickel, chromium, europium, yttrium, samarium or gadolinium. The manner in which the metal oxides are present in these domains can be in a simple form or in various forms. A particularly preferred magnetic domain is iron oxide in the form of gamma-Fe203 (Y-Fe203) and / or Fe304. The magnetic domains can further take the form of mixed oxides of at least two metals, using the following metal components: iron, cobalt, nickel, tin, zinc, cadmium, magnesium, manganese, copper, barium, magnesium, lithium or yttrium. The magnetic domains can be even more, being the substances whose general formula is? Tt? 2? 4, where M11 is a metal component that covers at least two different divalent metals. One of the divalent metals may preferably be manganese, zinc, magnesium, cobalt, copper, cadmium or nickel. The magnetic domains can also be composed of tertiary systems of the general formula (Mai x and MbxFey) IIFe2III04, where Ma and Mb respectively can be manganese, cobalt, nickel, zinc, copper, magnesium, barium, yttrium, tin, lithium, metals. cadmium, magnesium, calcium, strontium, titanium, chromium, vanadium, niobium or molybdenum, where x = 0.05 to 0.95, y = 0 to 0.95 and x + y < 1. Particularly preferred compounds are ZnFe204, nFe204, Mn0.6Feo.4Fe204, MNo.sZno.5Fe204i Zn0.iFei.9O4 / Zn0.2Fei.8O4, Zno.3Fe1.7O4 or MN0.39Zno.27Fe2.3404, MgFe203, Mg1.2Mno.2 e1.2O4, Mg1.6Mno.6Feo.804, Mgi.6Mno.6Feo.804, There is no additional restriction on the choice of non-magnetic matrix metal oxide. These may preferably be oxides of titanium, zirconium, zinc, aluminum, silica, cerium or tin. For the purposes of the invention, the term metal oxides includes metalloid oxides, such as silica dioxide. The matrix and / or domains can also be amorphous and / or crystalline.

The portion of the magnetic domains in the particles is not subject to any restriction, as long as there is spatial separation of the matrix and the domains. The ratio of the magnetic domains in the super-paramagnetic particles can preferably be from 10 to 90% by weight. The inventive plastic materials may preferably have a super-paramagnetic particle ratio in the range of 0.1 to 40% by weight. Suitable super-paramagnetic particles are described by way of example in EP-A-1284485, and also in DE 10317067, the entire contents of which are incorporated herein by reference. Correspondingly, the super-magnetic particles can be obtained through a process comprising the following compound comprising the metal component or the metalloid component of the non-magnetic matrix and a compound comprising the metal component of the super-paramagnetic domains. , wherein at least one of the compounds contains chlorine and wherein the constitution of the vapor corresponds to the subsequently desired relationship of the super-paramagnetic domains and the non-magnetic matrix; - The introduction of this mixture in a mixing zone, where it is mixed with air and / or oxygen and with a combustion gas, and introducing the mixture into a burner of known design and combustion of this mixture in a flame inside a combustion chamber; - The cooling of hot gases and solid product, the removal of gases from the solid product and, if correct, the purification of the solid product through heat treatment by means of gases moistened with water vapor. These particles can also be obtained through an operation that includes the following steps: - The production of an aerosol through the atomization of a precursor that comprises the metal component of the superparamagnetic domains and takes the form of a solution or a dispersion. of salt; - The mixture of this aerosol with the gas mixture from a process of hydrolysis by flame or from a process of oxidation by flame, where the mixture comprises the precursor of the non-magnetic matrix, in a mixing zone, where the constitution of the vapor corresponds to the subsequently desired relationship of the superparamagnetic domains and the non-magnetic matrix; - The introduction of the gas-aerosol mixture in a burner of known design and the combustion of this mixture in a flame inside a combustion chamber; - The cooling of hot gases and solid product, the removal of gases from solid product and, if correct, the purification of solid product through heat treatment by means of gases moistened with steam; - Where the precursor of the superparamagnetic domains and / or the precursor of the non-magnetic matrix is a compound containing chlorine. The particles can also be obtained through an operation that includes the following steps: - The production, separately or together, of an aerosol through the atomization of a precursor of the supermagnetic domains and of a precursor of the non-magnetic matrix, where these precursors take the form of a solution or dispersion of salts and where the constitution of the aerosol corresponds to the subsequently desired relationship of the super-paramagnetic domains and the non-magnetic matrix; - The introduction, separately or together, of the aerosols of the precursors in a mixing zone, in which they are mixed with air and / or oxygen and with a combustion gas, and; - The introduction of the aerosol-gas mixture in a burner of known design and the combustion of this mixture in a flame inside a combustion chamber; - The cooling of hot gases and the solid product, the removal of gases from the solid product and, if correct, the purification of the solid product through heat treatment by means of moistening the gases with water vapor; - Where the precursor of the superparamagnetic domains and / or the precursor of the non-magnetic matrix is a compound containing chlorine. The combustion gases that can be used preferably are hydrogen or methane. With respect to the ease of welding, the selection of polymer materials underlying the plastic materials of the invention is such that the plastic material that generates the weld preferably can be based on one or two polyurethane components, one or two polyepoxide components , one or two components of silicone polymer, modified silane polymer, polyamide, functional (meth) acrylate polymer, polyester, polycarbonate, cyclo-olefin copolymer, polysiloxane, poly (ether) sulfone, polyether ketone, polystyrene, polyoxymethylene, polyamidimide, polytetrafluoroethylene, polyvinylidene fluoride, propylene copolymer of perfluoroethylene , perfluoroalkoxy copolymer, methacrylate / butadiene / styrene copolymer and / or liquid-crystalline copolyester. The production method for the plastic material comprises nano-scale magnetic oxide particles, preferably mixtures, extrusions and then pills of the underlying polymer materials in the form of powder or pearls with magnetic oxide particles at nano-scale in form of a powder. This form can be particularly advantageous for polyamide polymers. The plastic material then takes the shape of the pills, which can, in turn, be processed through extrusion to give molds, semi-finished products, sheets, sheets and the like. The plastic material can, if correct, be composed not only of polymers but also of polymerizable monomers, water or an organic dispersion medium. The suitable organic dispersion medium can, by way of example, be selected from oils, fats, waxes, esters of C6-C30 monocarboxylic acids with mono, di or trihydric, cyclic and saturated acyclic hydrocarbons, fatty alcohols and mixtures thereof. Among these are, by way of example, paraffins and paraffin oils, mineral oils, linear saturated hydrocarbons having generally more than 8 carbon atoms, for example, tetradecane, hexadecane, octadecane, etc., cyclic hydrocarbons, for example cyclohexane and decahydronaphthalene, waxes, esters of fatty acids, silicone oils, etc. Preferred examples are linear and cyclic hydrocarbons and alcohols. The plastic material comprising the nano-scale magnetic oxide particles which is used according to the invention as a means for generating welding during the production of a plastic composite mold by welding in an alternating electromagnetic field. The plastic molds to be joined may be composed entirely or to some extent of plastic material comprising particles of magnetic oxide at nano-scale. At least one of the molds to be joined here is composed, at least in the region of the joining zone, of this plastic material. The plastic molds can be produced in a manner known per se and in any desired shape. The molds partially provided with particles of nano-scale magnetic oxide, for example, only in the region of the joint zone, can be obtained, by way of example, through co-extrusion or sequential coextrusion, multi-layer extrusion, injection molding of multiple components or by coating. The preliminary products that will join, can, by way of example, be components of hollow bodies. These can be processed to give assembled hollow bodies, such as containers, tubes or lines, that have been welded directly or by means of connection elements, such as sleeves, adapters or flanges. The plastic material that generates the weld may also be present separately, for example in the form of sheets or sheets that are placed between plastic parts resembling sheets and joining them, such as a welding element. The resulting plastic composite molds take the form of multilayer composites composed of welded elements in the manner of a sheet, the examples being sheets and / or sheets. In the corresponding process, the plastic molds to be joined are exposed at least in the region of the joining area to an alternating electric, magnetic or electromagnetic field, where the plastic material generating the weld is heated to melting point.

For the heating process, it is preferable to use an alternating electromagnetic field whose frequency is within a range of 30 Hz to 100 MHz. The known inductor frequencies are adequate, the examples are medium frequencies within the range of 100 Hz to 100 kHz or high frequencies within the range of 10 kHz to 60 MHz, in particular 50 kHz to 3 MHz. The magnetic domains and in particular the nanoparticle domains of the super-paramagnetic particles allow the effective use particularly of the energy input of a radiation electromagnetic available This also applies through analogy to heating through alternating electromagnetic fields of microwave radiation. It is preferable here to use microwave radiation whose frequency is in the range of 0.3 to 300 GHz. In addition to microwave radiation, it is preferable to use a DC magnetic field whose field strength is in the range of 0.001 to 10 teslas, for the resonant frequency adjustment. The resistance of the field should preferably be in the range of 0.015 to 0.045 teslas and in particular 0.02 to 0.06 teslas. Example 1 Production of super-paramagnetic particles Particles P-l: 0.57 kg / h of SiCl4 are vaporized at 200 ° C and are fed in a mixing zone with 4.1 Nm3 / h of hydrogen, and also 11 Nm3 of air. An aerosol obtained from 25% by weight of an aqueous solution of iron (III) chloride (1.27 kg / h) is also introduced by means of a carrier gas (3 Nm3 / h of nitrogen) in a mixing zone , inside the burner, where the gas-aerosol mixture that is homogeneously mixed is subject to a combustion at an adiabatic combustion temperature of about 1200 ° C and with a residence time of about 50 msec. After the reaction, a known method is used to cool the reaction gases and the resulting particulate powder, and, this is isolated by means of a filter from the exhaust gas flow. In a subsequent step, the remaining adherent hydrochloric acid residues are removed from the powder through a nitrogen treatment comprising steam. P-2 particles: 0.17 kg / h of SiCl4, they are vaporized at 200 ° C and are fed into a mixing zone with 4.8 Nm3 / h of hydrogen and also 12.5 Nm3 / h of air. An aerosol obtained from 25% by weight of an aqueous solution of iron (III) chloride (2.16 kg / h) is also introduced by means of a carrier gas (3 Nm3 / h of nitrogen) inside of the mixing zone, inside the burner, where the gas-aerosol mixture that is homogeneously mixed is subjected to combustion at an adiabatic combustion temperature of about 1200 ° C and with a residence time of 50 msec. After the reaction, a known method is used to cool the reaction gases and the resulting particulate powder, and this is isolated by means of a filter from the exhaust gas flow. In a further step, the adhering hydrochloric acid residues are removed from the powder through a nitrogen treatment comprising steam. Particles P-3: 0.57 kg / h of SiCl4 precursor of the matrix, vaporize at around 200 ° C and feed with 4 Nm3 / h of hydrogen, and also 11 Nm3 / h of air and 1 Nm3 / h of nitrogen in the reactor. An aerosol composed of the domain precursors and obtained by means of a twin fluid nozzle of an aqueous solution in which iron (II) chloride, magnesium chloride (II) and manganese chloride are present is also introduced into the reactor by means of a carrier gas (3 Nm3 / h of nitrogen). The aqueous solution comprises 1.8% by weight of MnCl2, 8.2% by weight of MgCl2 and 14.6% by weight of FeCl2. The gas mixture - homogeneously mixed spray it flows into the reactor, where it undergoes a combustion with an adiabatic combustion temperature of around 1350 ° C and with a residence time of around 70 msec. The residence time is calculated from the ratio of the volume of plant through which the substance flows and the flow rate of the operating volume of the process gases to an adiabatic combustion temperature. After the process of flame hydrolysis, the reaction gases and the resulting powder of zinc-magnesium-ferrite-neutralized silicon dioxide are cooled, and the solid is isolated by means of a filter from the exhaust gas flow. In a further step, the remaining adherent hydrochloric acid residues are removed from the powder through the nitrogen treatment comprising steam. Example 2 Production of plastic materials comprising super-paramagnetic particles Example 2.1 2 kg of particles P-l of Example 1 are mixed in the melt, extruded and pelletized with 8 kg of polyamide pills (Vestamid® L1901; terminology for ISO 1874-1; PA12, XN. 18-010; Degussa AG) in a double screw extruder ZE25-33D from Berstorff, at 250 ° C with a production of 10 kg / h. Example 2.2 2 kg of particles Pl of Example 1 are mixed in the melt, extruded and pelletized with 8 kg of Vestodur® X9407 polyurethane terephthalate pills from Degussa AG in a twin screw extruder ZE25-33D from Berstorff, at 250 ° C with production of 10 kg / h. Example 2.3 2 kg of particles Pl of Example 1 are mixed in the melt, extruded and pelletized with 8 kg of polypropylene copolymer pills (Admer® QF551A from Mitsui Deutschland GmbH) in a twin screw extruder ZE25-33D from Berstorff at 200 ° C with production of 10 kg / h. Example 2.4 2 kg of particles Pl of Example 1 are mixed in the melt, extruded and pelletized with 8 kg of nylon-6 pills (Ultramid® B4 of BASF AG) in a twin screw extruder ZE25-33D of Berstorff, at 250 ° C with production of 10 kg / h. Example 2.5 2 kg of particles P-l of Example 1 are mixed in the melt, extruded and pelletized with 8 kg polyvinylidene fluoride (DUFLOR® X7394 from Degussa AG) in an extruder of double screw ZE25-33D of Berstorff, at 250 ° C with production of 10 kg / h. Example 2.6 2 kg of particles Pl of Example 1 are mixed in the melt, extruded and pelletized with 8 kg of polyamide pills (Vestamid® D18 from Degussa AG) in a twin screw extruder ZE25-33D from Berstorff, at 200 ° C. C with production of 10 kg / h. Example 2.7 2 kg of particles Pl of Example 1 are mixed in the melt, extruded and pelletized with 8 kg of polyamide pills (Vestamid® D18 of Degussa AG) in a twin screw extruder ZE25-33D of Berstorff, at 200 ° C with production of 10 kg / h. Example 3 Welding of plastic molds in an alternating electromagnetic field General Method: The plastic materials according to Examples 2.1 to 2.7, comprise super-paramagnetic particles, were extruded to obtain sheets with a thickness of 1 mm. Each of these sheets was alternated with a sheet of the same or different underlying plastic material (without super-magnetic particles), and this structure of Multiple layers are secured through winding with adhesive tape. The multi-layer structure was placed for the prescribed time in an alternating electromagnetic field at 100% power. The data for the inductor coil were as follows: Measurements: 200 x 45 x 40 mm3 (L x W x H) Material: tetragonal copper tube 10 x 6 x 1 mm Effective cross section area: 28 mm2 Coil fed length: 120 mm Coil rotation number: 3 Coil winding length (ef.): 35 mm Coil diameter (internal): 20 mm to 40 mm Coil internal area: 720 mm2 Inductance (at 100 kHz) : around 270 nH Operating frequency: 323 kHz The data for the high-frequency semiconductor generator used were as follows: Producer: STS - Systemtechnik Skorna GmbH Model: STS type M260S Terminal power: 6 kw Inductance range: 250 - 1200 nH Operating frequency: 150 to 400 kHz (323 kHz using inductor coil) The following grades were used to access the adhesion after removal of the specimen from the alternate field: 0 No adhesion 1 Very little adhesion 2 Certain adhesion; easy to separate 3 Good adhesion; can not be separated without great effort and sometimes the use of a tool 4 inseparable link; impossible to separate without cohesive fracture EXAMPLES

Claims (17)

1. CLAIMS 1. A plastic composite mold that is obtained by welding in an alternative electromagnetic field where the welding is obtained through the aid of a plastic material comprising particles of magnetic oxide at nano-scale, characterized in that the particles of Magnetic oxide to nano scale are composed of aggregated primary particles, where the primary particles are composed of metal oxide domains whose diameter is from 2 to 100 nm in a non-magnetic metal oxide matrix or a non-magnetic metalloid oxide matrix.
2. 2. A plastic composite mold according to claim 1, characterized in that the plastic material generating the weld comprises nano-scale magnetic oxide particles.
3. 3. A plastic composite mold according to claim 2, characterized in that the plastic material that generates the weld comprises nano-scale magnetic oxide particles that are composed of aggregated primary particles, wherein the size of the aggregate of the particles of Magnetic oxide is greater than 100 nm and lower than 1 pm.
4. 4. A plastic composite mold according to any of Claims 1 to 3, characterized because the magnetic domains of the magnetic oxide particles comprise iron oxide.
5. 5. A plastic composite mold according to any of Claims 1 to 4, characterized in that the nanoscale magnetic oxide particles have agglomerated super paramagnetic domains.
6. 6. A plastic composite mold according to any of Claims 1 to 5, characterized in that the magnetic domains of the paramagnetic super oxide particles comprise ferrites.
7. 7. A plastic composite mold according to any of Claims 1 to 7, characterized in that the magnetic domains of the super-paramagnetic oxide particles are composed of tertiary systems of the general formula (M *! X and MbxFey) "Fes111 * ^, where Ma and Mb = manganese, cobalt, nickel, zinc, copper, magnesium, barium, yttrium, tin, lithium, cadmium, magnesium, calcium, strontium, titanium, chromium, vanadium, niobium or molybdenum, and, x = of 0.05 to 0.95, y = from 0 to 0.95, and x + y < 1.
8. 8. A plastic composite mold according to Claims 1 to 7, characterized in that the ratio of the magnetic domains in the magnetic oxide particles to nano-scale is from 10 to 90% by weight
9. 9. A plastic composite mold according to any of Claims 1 to 8, characterized because the proportion of the particles of magnetic oxide to nano-scale in the plastic material that generates the welding is from 0.1 to 40% by weight.
10. 10. A plastic composite mold according to any of claims 1 to 9, characterized in that the plastic material generating the weld can be thermoplastically smoothed.
11. A plastic composite mold according to Claim 10, characterized in that the plastic material generating the weld is based on one or two polyurethane components, one or two polyepoxide components, one or two silicone polymer components, polymer modified silane, polyamide, functional (meth) acrylate polymer, polyester, polycarbonate, cyclo-olefin copolymer, polysiloxane, poly (ether) sulfone, polyether ketone, polystyrene, polyoxymethylene, polyamidimide, polytetrafluoroethylene, polyvinylidene fluoride, copolymer of polyfluoroethylene propylene, perfluoroalkoxy copolymer, methacrylate / butadiene / styrene copolymer and / or liquid-crystalline copolyester.
12. 12. A plastic composite mold according to any of Claims 1 to 11 in the form of assembled hollow bodies, such as containers, tubes or lines, which have been welded directly or by means of connection elements, such as shirts, adapters or flanges.
13. 13. A plastic composite mold according to any of claims 1 to 12 in the form of a multilayer composite composed of welded elements in the form of sheets, the examples being sheets and / or sheets.
14. 14. A process for the production of a plastic composite mold by welding in an alternating electromagnetic field, characterized in that the welding is achieved with the aid of a plastic material comprising particles of magnetic oxide at nano-scale which is composed of aggregated primary particles, where the primary particles are composed of magnetic metal oxide domains whose diameter is 2 to 100 mm in a non-magnetic metal oxide matrix or a non-magnetic metalloid oxide matrix.
15. 15. A process according to claim 14, characterized in that at least one of the molds to be joined is composed at least in the region of the joint area of a plastic material comprising nano-scale magnetic oxide particles, which is composed of aggregated primary particles, wherein the primary particles are composed of a magnetic metal oxide domain whose diameter is from 2 to 100 nm in a non-magnetic metal oxide matrix or a non-magnetic metalloid oxide matrix.
16. 16. A process according to claim 14 or claim 15, characterized in that the plastic molds to be joined are exposed at least in the region of the area of attachment to an electric, magnetic or electromagnetic field, where the plastic material that generates the weld It is heated to a melting point.
17. 17. The use of magnetic oxide particles at nano-scale as an additive in plastic materials, where these particles are composed of aggregated primary particles and where the primary particles are composed of magnetic metal oxide domains whose diameter is from 2 to 100 nm in a matrix of non-magnetic metal oxide, in order to provide ease of welding thereof in an alternating electromagnetic field.