Magnetic, functionalized polymer substrate for high-frequency application

Abstract

To provide a magnetodielectric polymer composite material with increased refractive index and greatly reduced attenuation losses for the miniaturization of antennas in a MHz and bordering GHz frequency range.SOLUTION: There is provided a magnetodielectric polymer composite material, in which, through the use of a polymer compound that is highly branched in the polymer concerned, a magnetic filler component is more efficiently dispersed during processing, and is also better incorporated in a 0-3 structure with a surrounding polymer matrix by virtue of the spacer function of the polymer compound.SELECTED DRAWING: None

Description

[Technical field]

[0001] This patent describes a magnetic dielectric polymer composite with enhanced refractive index and significantly reduced attenuation losses for antenna miniaturization in the MHz and adjacent GHz frequency range, in which the magnetic filler component is efficiently dispersed during processing and well integrated into the 0-3 structure with the surrounding polymer matrix due to the spacer function of the compound, by using highly branched polymer compounds in the polymer. [Background technology]

[0002] Magnetic dielectric polymer composites are heterogeneous mixtures of one or more magnetic filler components in a dielectric plastic matrix, integrating the properties of both magnetic and dielectric materials into the plastic.

[0003] According to the studies by Mosallaei and Sarabandi in “Magneto-Dielectrics in Electromagnetics: Concepts and Applications”, IEEE Transactions on Antennas and Propagation Vol. 52, No. 6 (2004) pp. 1558-1569 and by Juuti and Teirikangas in “Thermoplastic 0-3 Ceramic-Polymer Composites with Adjustable Magnetic and Dielectric Characteristics for Radio Frequency Applications”, International Journal of Applied Ceramic Technology Vol. 7, No. 4 (2010) pp. 452-460, magneto-dielectric polymer composites may be used as substrates for miniaturizing high frequency devices such as antennas.

[0004] The study by Yang et al., "Comprehensive Study on the Impact of Dielectric and Magnetic Loss on Performance of a Novel Flexible Magnetic Composite Material," published in the proceedings of the 38th European Microwave Conference, held in Amsterdam in October 2008, concerns the application of magnetic dielectric polymer composites in radio frequency identification systems (RFID).

[0005] In their 2020 paper, “Flexible Magnetic Polymer Composite Substrate with Ba 1.5 Sr 1.5 In “Z Hexaferrite Particles of VHF / Low UHF Patch Antennas for UAVs and Medical Implant Devices”, Materials 2020, 13, 1021 pp. 1-10, we report on the miniaturization of antennas using an integrated flexible polymer composite of polyurethane / hexaferrite that can be used in the frequency range of several hundred MHz, especially up to 400 MHz in drones or medical implants.

[0006] Using a magnetic dielectric polymer composite, the miniaturization relationship in the context of a stripline antenna with the refractive index n and the miniaturization factor k, in terms of the real components of the permittivity ε' and permeability μ', is as follows:

number

[0007] Stripline antennas using magnetic dielectric polymer substrates have a higher refractive index since μ>1 compared to purely dielectric filled polymer composites and also have better impedance matching IM according to Eq. (2).

number

[0008] Impedance matching IM=(μ' / ε') 1 / 2 In the ideal case of I = 1 or impedance difference ID = 0, reflections and surface waves in a stripline antenna disappear, but such phenomena can themselves cause a certain power loss during operation of the antenna.

[0009] If the magnetic dielectric polymer substrate is chosen unfavorably, especially in the case of strongly damping magnetic fillers and polymer matrices, significant magnetic and dielectric damping losses, and therefore losses of power absorbed and output during reception and transmission by the antenna, can occur in the MHz and GHz frequency range. The resonant frequency f r For antennas with high radiation efficiency and relatively large antenna gain in the range, the dielectric and magnetic attenuation losses of the polymer composite materials used must be very small. The loss tangent values ​​are calculated from the quotient of the imaginary components μ” and ε” and the associated real components ε’ and μ’, respectively, and the attenuation losses are still sufficiently small, less than 0.1.

number

[0010] In the manufacture of magnetic dielectric filled polymer composites, the aim is a high degree of dispersion and substantial individualization of the magnetic filler particles in a 0-3 environment with the polymer matrix. An overview of purely dielectrically filled and magnetically filled polymer-ceramic composites with three-dimensional connectivity of the ceramic component to the polymer phase is given in the work of Sebastian and Jantunen, “Polymer-Ceramic Composites of 0-3 Connectivity for Circuits in Electronics: A Review”, International Journal of Applied Ceramic Technology, Vol. 7, No. 4, (2010) pages 415-434.

[0011] Van der Waals forces are weak interactions between atoms and molecules that, according to Winkler in his paper “Dispergieren von Pigmenten und Fuellstoffen, Farben und Lacke”, published by Vincentz in November 2010, SBN-10:3866309090, decrease by the sixth power as the distance increases, including between filler particles.

[0012] According to a 2015 study by Damavandi at TU Kaiserslautern in his dissertation, “Effect of internal surfaces on the structural and mechanical properties of polymer-metal composites”, section 2.5.5 “Internal surface of the fillers”, van der Waals forces and the tendency to form aggregates increase significantly with increasing packing density, especially when the filler particle size is reduced from a few micrometers to particles with sub-micron or nanoscale dimensions.

[0013] The reduced dispersion and insufficient individualization of the magnetic filler components in the polymer substrate leads to a decrease in the permittivity ε' and the magnetic permeability μ', which is accompanied by a decrease in the refractive index of the polymer composite in the high frequency range.

[0014] The use of hyperbranched or dendritic polymer compounds aims to disperse magnetic filler particles in the polymer matrix and incorporate them in an ideal 0-3 environment with the polymer components. The special spacer function of hyperbranched polymers in highly filled magnetic dielectric polymer composites allows to increase the permittivity ε' and permeability μ', and therefore the refractive index of polymer-based antenna substrates.

[0015] According to Chapter 25, “Dispersants and Coupling” in “Applied Plastics Engineering Handbook”, edited by Myer Kutz, Elsevier Inc. 2017, ISBN: 978-0-323-39040-8, representative dispersing additives with chemical coupling effects suitable for incorporating fillers and pigments into plastics include organosilanes, organometallic compounds (such as titanates, zirconates and aluminates), polymers with unsaturated carboxylic acid, acrylic acid and maleic acid functional groups, which may also contribute to the steric stabilization and good cohesion of magnetic particles in magnetic dielectric polymer composites due to their anchor-buffer structure.

[0016] However, due to the polar nature of these dispersing adjuvants, the dielectric and magnetic damping losses of filled polymer composites increase rapidly.

[0017] Non-polar or polar wax additives without specific coupling function, such as polyolefin waxes, amide waxes and montan waxes, depending on their compatibility with the polymer matrix, may act as external lubricants (incompatible) and internal lubricants (compatible) and improve melt processability during processing, especially reducing viscosity.

[0018] The dispersing effectiveness of free-flowing wax additives is reduced in sintered ferrite due to the porosity of the ceramic particles and the increased absorption of the polymer melt at the open ferrite surfaces.

[0019] In 2015, the University of South Florida published U.S. Patent Application Publication No. 20150255196, “Magneto-Dielectric Polymer Nanocomposites and Method of Making,” the authors reported that CoFe in a butadiene copolymer solution 2 O 4 and Fe 3 O 4Nanoparticles have been claimed, and the surfactants oleylamine and oleic acid have been used to stabilize them, especially with respect to oxidation. However, in the absence of the spatial extent of the highly branched molecular structure of hyperbranched polymers or dendrimers, the surfactants described are unable to develop a suitable individualization and spacer effect between the magnetic particles in the polymer composite.

[0020] LG Electronics' 2018 patent KR20180060496, "Magnetic and Dielectric Composite Structure and Method for Fabricating the Same and Antenna for Using the Same," describes a SiO 2 composite material that is incorporated into a polymer matrix, such as polyvinylpyrrolidone, polydimethylsiloxane, PMMA, PET, cycloolefin copolymer, polystyrene, and polyethylene naphthalate, and used as a magneto-dielectric substrate for antennas (e.g., PIFA) from 700 MHz to 3 GHz. 2、 Al 2 O 3 , TiO 2 and ZrO 2 Coating of soft magnetic metal particles of Fe, Co, Ni, Mn and their alloys with particle sizes of 10-500 nm using electrically insulating oxides such as Cr, Co, Ni, Mn, and their alloys in layers of thickness 1-30 nm has been reported. However, the dielectric and magnetic damping values ​​(tanδ) of the antenna substrates in the frequency range investigated are not satisfactory. ε Approximately 0.25 and tan δ μ Since the upper limit of Equation 3 is much higher than the upper limit of Equation 3, the radiation efficiency and gain of these antenna systems are significantly reduced.

[0021] Rogers Corporation's 2019 patent, WO 2019143502, "Core-Shell Particles, Magneto-Dielectric Materials, Methods of Making, and Uses thereof," claims both the manufacture and use of magnetic particles in magneto-dielectric polymer composites having a core-shell structure (core-shell particles) for the frequency range near and above 1 GHz, where the shell of the Fe, Ni, or Co particles is formed by methods including oxidation using a chemical oxidant such as oxygen or in a plasma, and also from a nitride in a separate process step. The drawback of this additional process step is that the KMnO 4 , K 2 Cr 2 O 7 and HNO 3 One problem is the use of oxidizing agents such as dimethylformamide, dimethyl ether, dimethyl silane, etc., the reaction products of which must be removed from the process and from the treated magnetic particles.

[0022] In recent years, established nanoscale dispersing additives for filled polymer composites have included polyhedral oligosilsesquioxanes (POSS compounds).

[0023] Specific properties and applications of these semi-organic framework silicates are described in Xanthos's "Functional Fillers for Plastics", Chapter 23: Polyhedral Oligomeric Silsesquioxanes. WILEY-VCH, Weinheim, 2010 and in the 2019 study by Blanco et al. "POSS-Based Polymers", Polymers 11, 1727 pp. 1-5.

[0024] According to the paper by Lee, Hwang et al., “Low Dielectric Materials for Micro-electronics in Dielectric Materials”, edited by Silaghi, Chapter: 3, pp. 59-76, INTECH Open Access Publisher from January 2012, the dielectric constant, and therefore the refractive index, of polymer-POSS composites is reduced due to the nanocavities in the cage structure of the POSS compounds.

[0025] Thus, the incorporation of these semi-organic semi-organic framework silicates into the magnetic dielectric polymer composite to more effectively disperse the ferrite component works against the intended refractive index increase and miniaturization of the antenna substrate.

[0026] Blueshift Materials’ 2019 patent, WO 2019006184, “Hyperbranched POSS based Polymer Aerogels,” claims hyperbranched polymer aerogels composed of an open-cell polymer matrix and an organically modified POSS polymer.

[0027] The reduced density allows these polymeric materials to be used in high frequency applications, specifically as antenna substrates with reduced dielectric constants. The reduced density is also accompanied by a reduced refractive index for aerogels, making these materials unsuitable for miniaturizing antennas.

[0028] Gao and Yan, in their study “Hyperbranched Polymers: from Synthesis to Applications”, Progress in Polymer Science, 29, (2004) pp. 183-275, describe the potential of hyperbranched / dendritic polymer compounds to improve processability in plastics processing and in particular their suitability as dispersing additives for filled polymers.

[0029] In the review article by Douloudi et al., “Dendritic Polymers as Promising Additives for the Manufacturing of Hybrid Organoceramic Nanocomposites with ameliorated Properties suitable for an extensive Diversity of Applications”, Nanomaterials 2021, 11, 19, pp. 1-36, hyperbranched and dendritic polymers are also used as additives for analysis (chromatography), functional coatings in electronics and sensor technology, for chemical catalysis, and in medical applications (gene transfer, as antibacterial polymer composites, and for administration of active ingredients).

[0030] Also, in the context of magneto-dielectric materials, the 2018 Rogers Corporation patents, WO 2018119341 “Multi-Layer Magneto-Dielectric Materials” and WO 2018140588 “Method of Making a Multi-Layer Magneto-Dielectric Material”, mention the use of otherwise unspecified dendrimers, as well as the use of a large class of polymer matrices of thermoplastics and thermosets, but these are only used in the dielectric interlayers of the laminate and therefore cannot act as spacers in the 0-3 structure between the magnetic filler particles in the ferromagnetic layers.

[0031] U.S. Patent Application Publication No. 20090053512, a 2009 University of Arizona ABOR patent, entitled "Multifunctional Polymer coated Magnetic Nanocomposite Material," describes polymer-coated nanoparticles consisting of a metallic ferromagnetic core, specifically cobalt, and a polymer shell. These polymer-coated nanoparticles may also contain a dendritic / hyperbranched polymer shell. The shelled particles may also be oriented into chain-like structures under the action of a magnetic field.

[0032] According to the findings of the patent in US Patent Application Publication No. 20090053512 (paragraph 0155), shelled cobalt nanoparticles can be coated or used as microwave absorbers, but their use as low attenuation polymer-based antenna substrates is excluded.

[0033] Shenzhen Halcyon New Materials Co., Ltd.'s 2020 Chinese patent CN111548612, "PCT / LCP Resin Composition for 5G Antenna Oscillator Base Materials as well as Preparation Method and Application thereof," claims a polymer blend of PCT (cyclohexanedimethanol-dimethyl terephthalate-CHDM-DMT) and TLCP (thermoplastic LCP) with glass or wollastonite fibers or mineral components as an antenna substrate for the 5G frequency range.

[0034] Dispersion additives used in PCT / TLCP polymer composites include, in particular, hyperbranched polymers. However, the described PCT / TLCP polymer composites exist only as purely dielectric-filled polymer blends. The dielectric glass fibers or mineral components used contribute only slightly to increasing the refractive index of the polymer composites, in agreement with the review study by Sebastian, Ubic and Jantunen in 2017, “Microwave Materials and Application”, ISBN 9871119208525, First Edition, John Wiley & Sons, pp. 855 ff., due to the low dielectric constant of the fillers compared to the customary titanates, niobates or zirconates, and in particular the magnetic permeability μ' of the non-magnetic fillers is only 1.

[0035] A study by Menezes and Fechine et al., “From Magneto-Dielectric Biocomposite Films to Microstrip Antenna Devices”, Journal of Composite Science, 2020, 4, 144, pp. 1-20, saw the incorporation of superparamagnetic iron oxide nanoparticles (SPIONS) into the biopolymers chitosan, cellulose and collagen. To improve the dispersion of the magnetic iron particles in the polymer matrix and to increase their stability against oxidation, the surface of the nanoparticles was functionalized with hyperbranched polyethyleneimine (bPEI). The suitability of the resulting magneto-dielectric biocomposites as polymer substrates was then investigated in patch antennas.

[0036] In this case, μ' is set to 1 for the real component, so the complex permeability (μ*=μ'-iμ") and the magnetic damping loss tanδ μ The effect of is neglected. However, in the frequency range between 0.4 and 4.5 GHz, significant dielectric damping losses of 0.15–0.4 are found for the investigated biopolymer SPIONS. Combined with the fact that magnetic damping losses are not captured, the use of these highly damped polymer substrates for patch antennas is likely to result in a sharp decrease in antenna gain and radiation efficiency.

[0037] The concept of hyperbranched spacer molecules used below is related to the organic molecular structure of polymer compounds that are characterized by random three-dimensional spatial branching with numerous functional groups and nanocavities and have pseudocenters, so that when these molecules are used in filled polymer composites, the space occupancy function (spacer effect) is also evident. DISCLOSURE OF THEINVENTION

[0038] In the present invention, the palmitic acid C of hyperbranched polyethyleneimine (PEI) after amidation is 15 H 31 The reaction product with COOH was named PEI-C16, and stearic acid C 17 H 35The reaction product with COOH is named PEI-C18, and the abbreviation PEIA is introduced as a generic term.

[0039] It is an object of the present invention to improve the miniaturization of antennas of the patch, dipole and planar inverted-F antenna (PIFA) type, for example for the MHz and adjacent GHz frequency range.

[0040] This objective is achieved by the incorporation and presence of hyperbranched spacer molecules which, within a certain filler range or at a certain filler percentage of the magnetic component, increase the refractive index of the polymer substrate used and thus the permittivity ε' and the permeability μ'.

[0041] Polymer substrates containing hyperbranched polymer compounds used for antenna miniaturization take the form of magnetic dielectric polymer composites containing magnetic fillers, or polymer hybrids containing two or more magnetic filler components.

[0042] These magnetic dielectric polymer substrates are characterized by low dielectric and magnetic damping losses, and have a low tan δ ε = ε” / ε'<0.1 and tan δ μ = μ” / μ' < 0.1.

[0043] The magneto-dielectric polymer substrate achieves improved impedance matching IM by the addition of hyperbranched spacer molecules, with μ′>1 compared to μ′=1 for purely dielectric filled polymer composites, and antenna losses due to surface waves and reflections are also reduced.

[0044] The object of the present invention is achieved by using a magnetic dielectric polymer substrate loaded with magnetic particles surrounded by amphiphilic hyperbranched spacer molecules. The amphiphilic nature of the spacer molecules allows them to attach with their polar side to the high energy surface of the magnetic particles, while the non-polar regions of the spacer compound molecules can extend into the non-polar low energy polymer matrix. As a result, the magnetic particles are coated in a micellar manner by the hyperbranched spacer molecules and are incorporated into the matrix with 0-3 connectivity.

[0045] With the improvement of the dispersion and individualization of the magnetic particles, the permittivity ε' and permeability μ' of the magnetic dielectric polymer composites, and hence the refractive index, are increased, while the dielectric and magnetic damping losses are reduced by tan δ ε <0.1 and tan δ μ Decreases to a value of <0.1.

[0046] The magnetic particles used have soft magnetic properties such as low coercivity Hc<1000 A / m and low remanence (remanent magnetization), so that the value of the real component of the magnetic permeability is μ'>1 or μ'>>1.

[0047] The soft magnetic particles are ceramics or alloys containing the elements cobalt, iron, manganese, or nickel. Particularly suitable for use in polymer substrates for antenna miniaturization in the MHz and adjacent GHz frequency ranges is Z-type barium cobalt hexaferrite (Ba 3 Co 2 Fe 24 O 41 ), general formula Ni a Zinc (1-a) Fe 2 O 4 Nickel zinc ferrite, or magnetite (Fe 3 O 4 ) or any other combination of these materials. The average particle size d of the particles having soft magnetic properties 50 is in the range of 0.05 to 10.0 μm.

[0048] The spacer molecules used are hyperbranched polyethyleneimines that are further functionalized with non-polar groups, which allows the amphiphiles to both interact with the polar surfaces of the magnetic particles and to spread into the non-polar matrix. The magnetic particles are coated in micelles with the hyperbranched spacer molecules, which allows them to be more effectively individualized and more uniformly distributed in the matrix.

[0049] The hyperbranched spacer molecules are preferably functionalized with fatty acids, more preferably palmitic acid and stearic acid.

[0050] The polymer matrix is ​​the main component of the magnetic dielectric polymer substrate in the antenna structure. The matrix provides the strength and structure or flexibility of the plastics used.

[0051] The matrix material has a low dielectric decay tan δ ε <0.02, more specifically, tan δ ε<0.01, for example, polyolefins such as cyclic olefin polymers (COP), cyclic olefin copolymers (COC), polyethylene (PE) and polypropylene (PP), styrene-containing polymers such as polystyrene (PS), high impact modified polystyrene (HIPS) and acrylonitrile-butadiene-styrene copolymers (ABS), polyesters such as polyoxymethylene (POM), polyethylene terephthalate (PET), polybutylene terephthalate (PBT) and polyethylene naphthalate (PEN), polycarbonate (PC), polyphenylene ether (PPO), polyphenylene sulfide (PPS), polytetrafluoroethylene (PTFE), etc. Fluorine-containing polymers such as polyvinylidene fluoride (PTFE), polyvinylidene fluoride (PVDF), perfluoro(ethylene-propylene) (FEP) and ethylene-tetrafluoroethylene copolymer (ETFE), thermoplastic elastomers (TPE) such as polyether block amide (PEBA), one-component solid silicone elastomers such as room temperature vulcanization (RTV) or high temperature vulcanization (HTV) silicone rubber, liquid two-component silicone rubber (liquid silicone rubber, LSR) such as polydimethylsiloxane, or ethylene-propylene-diene rubber (EPDM, ethylene-propylene-diene; M group), epoxy resin casting compound (normal temperature or heat curing type) or acrylate-containing epoxy resin.

[0052] The polymer composite of the present invention is produced by compounding by extrusion or kneading of a thermoplastic matrix polymer or from a liquid particle dispersion of dissolved polymer containing a mixture of amphiphilic hyperbranched spacer molecules and magnetic particles. The magnetic dielectric polymer composite is obtained from the magnetic particle dispersion of dissolved polymer in a further process step after removing the solvent. "Polymer substrate" and "polymer composite" are synonymous and interchangeable in the context of the present invention.

[0053] The magnetically filled polymer composite is pelletized and processed in an injection molding machine to obtain a plate-like intermediate as a polymer substrate for an antenna, or a housing to house the antenna structure.

[0054] Filaments made from pellets of magnetic dielectric polymer composite material can be processed using the additive manufacturing method of fused filament fabrication (FFF) to obtain specific intermediates.

[0055] From the filament, a housing that houses the antenna is printed or the antenna structure is directly coated with a magnetic dielectric polymer composite material by the FFF process.

[0056] To produce magnetically filled polymer composites from one-component solid silicone elastomers or EPDM, the rubber is mixed with amphiphilic hyperbranched spacer molecules and magnetic particles in a kneader, and the mixture is then processed in a roll mill. The magnetically filled rubber mixture is pressed to obtain a plate-like intermediate that can be used as a polymer substrate for the miniaturization of antennas.

[0057] Magnetic particles and amphiphilic hyperbranched spacer molecules are dispersedly incorporated into liquid two-component silicone elastomer or other epoxy resin mixtures by a combined high-speed homogenization and ultrasonic treatment.

[0058] The liquid matrix / magnetic particle dispersion can be poured into the cavity and cured to obtain a plate-like intermediate, which is then used as the polymer substrate for the antenna structure. The liquid matrix / magnetic particle dispersion can also be cast to encapsulate the antenna, allowing for miniaturization of the antenna structure.

[0059] Pellets of magnetic dielectric polymer composites and hybrids can be obtained by drawing the melt as strands through a water bath, pelletizing the strands, and then compounding the polymer and ferritic filler in a twin screw extruder.The pellets are then molded in an injection molding machine to obtain plate-shaped intermediates.

[0060] The preparation of amidated polyethyleneimines (PEIA) such as PEI-C16 and PEI-C18 is described in the study by Gladitz, “Understanding Herstellung, Characterization and Application of Antimikrobiellen Metall-Hybriden for Behavior and Compounds,” a dissertation from the Martin Luther University Halle-Wittenberg dated March 12, 2015.

[0061] The PEIA component is metered into the polymer melt during compounding in the extruder. The PEIA is also incorporated into the polymer / ferrite dispersion by shearing in an acetone polymer solution together with the magnetic ferrite particles, which is then dried under reduced pressure.

[0062] After the organic solvent is removed by evaporation and the film-like residue is pelletized, the magnetically filled polymeric material can be injection molded into a plate-like intermediate body.

[0063] Another polymer composite containing ferrite fillers and amidated polyesterimine can be processed on a catheter extrusion line to yield 1.75 mm thick filaments that can then be printed to obtain plate-like intermediates, and can also be used to coat dipole-type antennas using fused filament fabrication (FFF).

[0064] Polymer adjuvants consisting of polyhedral oligosilsesquioxanes octamethyl-POSS (OMP) and trisilanol isobutyl-POSS (TSP) and the amphiphilic copolymer Tegomer P121 for the dispersion of hard wax-based polymer-filler concentrates are compared with amidated polyethyleneimine (PEIA) as a reference additive in magnetic dielectric polymer-ferrite composites. The permittivity ε' and permeability μ', and hence the refractive index n, of the polymer composites are significantly increased with sufficiently small attenuation losses, tan δ. ε <0.1 and tan δ μ<0.1, it can only be increased by using amphiphilically modified hyperbranched PEIA.

[0065] Preferred Use Magneto-dielectric polymer composites and hybrids have low dielectric and magnetic damping losses, tan δ ε = ε” / ε'<0.1 and tan δ μ Provided that = μ″ / μ′<0.1, it can be used as a substrate material for the miniaturization of antennas in the MHz and adjacent GHz range.

[0066] The amphiphilic hyperbranched polymer PEIA acts as a dispersing aid when the magnetic dielectric composites are processed by extrusion or by incorporation into liquid polymer-ferrite particle dispersions, and unlike the assumed reference additives OMP, TSP and P121, it also acts as an effective spacer molecule between the magnetic filler particles in the polymer composite.

[0067] Since both the permittivity ε' and permeability μ' of the magnetic dielectric polymer composites and hybrids increase with the PEIA component, the refractive index increases significantly, which can be utilized, for example, to further miniaturize the antenna structure or to conserve magnetic fillers while reducing attenuation losses.

[0068] The usable frequencies of the magnetic dielectric polymer composite material of the present invention containing the spacer compound PEIA in small antennas are the emergency frequency of 400 MHz and the mobile communication standard LTE (Long Term Evolution) / 4G 800 MHz or the lower 5G range of 700 to 900 MHz, although the larger frequency range of 50 MHz to 4 GHz is preferred for polymer substrates. [Brief description of the drawings]

[0069] [Figure 1] FIG. 1 shows that modification of hyperbranched PEI with fatty acids of the general formula R-COOH affords amphiphilic hyperbranched PEI (PEIA). [Diagram 2] Figure 2 shows a schematic of the interaction of PEIA (100), which consists of non-polar regions (101) and polar regions (102), with magnetic particles (103) to produce PEIA-coated magnetic particles (104). In the polymer composite (105) of the PEIA-coated magnetic particles (104) and matrix polymer (106), the magnetic particles are individualized by the coating. [Diagram 3] FIG. 3, for example, compares the permittivity ε′, permeability μ′ and refractive index of COC-hexaferrite composites without additional additives, with OMP and with PEIA spacer compound, using practically relevant frequencies of 400 and 800 MHz. [Figure 4] FIG. 4 compares the permittivity ε′, magnetic permeability μ′ and refractive index of ABS-spinel ferrite composites without additional additives, with POSS additives OMP and TSP, and with PEIA compound at 400 and 800 MHz. [Diagram 5] FIG. 5, for example, contrasts the dielectric and magnetic damping losses of ABS-spinel ferrite composites with no additional additives, with POSS additives OMP and TSP, and with a PEIA compound, using a frequency of 800 MHz. [Figure 6] FIG. 6 shows the increase in permittivity ε′, permeability μ′ and refractive index of ABS-magnetite hexaferrite and ABS-spinel hexaferrite hybrids with PEIA spacer compound at 400 and 800 MHz. [Figure 7] Figure 7 shows the experimental setup for the measurement of the shift in resonant frequency due to the surrounding magneto-dielectric material of a flat antenna dipole. The flat antenna dipole (700) is embedded on two sides by magneto-dielectric substrate layers (701). The S11 scattering parameter is measured via port 1 (702) of the network analyzer (703). [Figure 8]Figure 8 shows the shift in resonant frequency of a 9.4 cm long dipole antenna in various magnetic dielectric environments as a function of frequency and refractive index. (800) Antenna in air environment (801) Antenna with ABS (802) Antenna with ABS-65gFi130 composite (803) Antenna with ABS-65gFi130-2 OMP composite (804) Antenna with ABS-65gFi130-2 TSP composite (805) Antenna with ABS-65gFi130-2 PEIA composite [Figure 9] FIG. 9 shows the resonant frequency shift of an antenna structure with two dipoles before coating with air dielectric (900) and after application of a polymer substrate (901) after coating by a 3D printing process with the magneto-dielectric polymer composite UBE-65gFi130-2PEIA and amphiphilically modified polyester-imine components. [Figure 10] FIG. 10 shows a photograph of the antenna structure before coating (1000) and after application of the magnetic dielectric polymer composite material UBE-65gFi130-2PEIA (1001). EXAMPLES

[0070] Working Example method Using the Agilent E4991A impedance analyzer, complex permeability μ was measured through measurement sockets 16454A and 16453A in the frequency range of 10 MHz to 1 GHz. * (μ', μ" and tan δ μ ) and complex permittivity ε * (ε', ε" and tan δ ε ) was measured. The complex permeability μ* was measured using a holed disk with an outer diameter of 19 mm, an inner diameter of 6 mm, and a thickness of 2 mm. The complex permittivity ε * was measured as a function of frequency on 19 mm diameter and 2 mm thick coupons obtained by milling from magneto-dielectric polymer composites and hybrids.

[0071] Chemicals APEL™ APL5014DP is a cyclic olefin copolymer from Mitsu Chemicals America, Inc. with an MFI of 36 g / 10 min, 260° C. / 2.16 kg as measured according to ASTM D1238.

[0072] ELIX ABS 3D GP is an acrylonitrile-butadiene-styrene copolymer from ELIX Polymers, Tarragona, with an MVR of 18 cm according to ISO 1133. 3 / 10min, 220℃ / 10kg.

[0073] UBE68 UBESTA XPA 9068X1 is a polyamide 12 elastomer from Ube Industries, Ltd., Japan, with a MFR of 4g / 10min, 190°C / 2.16kg measured according to ISO 1133-2.

[0074] Co 2 Z is Trans-Tech's Z-type Ba 3 Co 2 Fe 24 O 41 Hexaferrite, d 50 is approximately 5.1 μm.

[0075] gFi130 is a ferrocarite-type NiZn ferrite from Sumida AG, and the d 50 is approximately 0.7 μm.

[0076] Fe 3 O 4 is Lanxess E8707H magnetite, d mean is approximately 0.2 μm.

[0077] Octamethyl-polyoligosilsesquioxane (Octamethyl-POSS, OMP) and trisilanol-isobutyl-polyoligosilsesquioxane (Trisilanol-isobutyl-POSS, TSP) were obtained from Hybrid Plastics, Hattiesburg, MD.

[0078] The dispersion additive Tegomer® P121 is an amphiphilic copolymer from Evonik Nutrition & Care GmbH.

[0079] PEIA is an amidated polyethyleneimine. Its preparation is described in the study by Gladitz, "Untersuchungen zur Herstellung, Characterisierung und Application of antimikrobiellen Metall-Hybriden fur Beschichtungen und Compounds", dissertation, Martin Luther University Halle-Wittenberg, March 12, 2015.

[0080] The polymers, magnetic fillers and special additives used, as well as the detailed processing conditions of the magnetic dielectric polymer composites are shown in Table 1.

[0081] [Table 1]

[0082] In the example given, BASF's polyethyleneimine Lupasol® WF was used, with an average molecular weight of 25,000, a water content of less than 1% and a viscosity (50°C) of 13,000-18,000 mPa·s, which was then amidated with Roth's palmitic acid, with a melting point of 62.5°C and a molecular weight of 256.4 g / mol.

[0083] Example 1 Cyclic olefin copolymer APEL™ APL5014DP was extruded with 60 and 65% Co by weight. 2 Z hexaferrite (Ba 3 Co 2 Fe 24 O 41 ), and in both cases 2% powdered PEIA was incorporated.

[0084] 60 and 65% by weight Co2 For comparison, two formulations containing Z hexaferrite contained no PEIA, and for two corresponding formulations, 2% of the POSS compound OMP was introduced into the COC matrix by extrusion.

[0085] The increased permittivity ε' and permeability μ', and resulting higher refractive index of the magneto-dielectric polymer composite containing amidated polyethyleneimine (PEIA) compared to the comparative formulation containing the POSS compound OMP but without PEIA, is confirmed in Figure 3 at both 400 MHz and 800 MHz.

[0086] Example 2 The polymer ELIX ABS 3D GP was extruded with 65 and 69% by weight of finely ground spinel ferrite gFi130 (NiZn-Fe 2 O 4 ), and in both cases 2% powdered PEIA was incorporated.

[0087] For the two formulations containing 65 and 69% by weight of the spinel ferrite gFi130, no PEIA was included for comparison, for the two formulations containing 65% by weight of gFi130, 2% of the POSS compounds OMP and TSP were included in each case, and for a further reference formulation 2% of the dispersing additive Tegomer P121 was incorporated.

[0088] The use of amidated polyethyleneimine (PEIA) leads to an increase in the permittivity ε' and permeability μ' of the magneto-dielectric polymer composites compared to the tested formulations containing the POSS compounds OMP and TSP without PEIA, and a resulting higher refractive index, which can also be seen at 400 and 800 MHz in Figure 4.

[0089] Example 3 To compare the dielectric and magnetic damping losses, 60, 65, and 69 mass% finely ground spinel ferrite gFi130 (NiZn-Fe 2 O 4) was incorporated into the polymer ELIX ABS 3D GP.

[0090] In further formulations containing 65% by weight of the spinel ferrite gFi130, 2% by weight of the POSS compounds OMP and TSP, and in the formulation containing 65% by weight of gFi130, 2% of the dispersing additive Tegomer P121 was incorporated by extrusion as the reference formulation.

[0091] The dielectric and magnetic damping losses of these reference samples were then compared with the corresponding loss tangent values ​​of extruded ABS-ferrite composites with loading levels of 65 and 69 wt % of the spinel ferrite gFi130, in both cases containing a PEIA component of 2 wt %.

[0092] Due to the more effective dispersion and better spacer effect of amidated polyethyleneimine, the dielectric attenuation losses, especially for the ABS-65gFi130-2PEIA and ABS-69gFi130-2PEIA formulations, are reduced by 25.8 and 51.5%, respectively, compared to the formulation without PEIA.

[0093] Consistent with Figure 5, lower dielectric damping losses were consistently achieved using PEIA compared to ABS-ferrite composites containing the POSS compounds OMP and TSP, and also when using the dispersion additive Tegomer P121. For ABS-gFi130 composites containing 65 and 69 wt. % ferrite and 2 wt. % PEIA, the dielectric and magnetic damping losses were significantly lower at both 400 and 800 MHz than the tan δ ε = ε” / ε'<0.1 and tan δ μ =μ” / μ'<0.1 was achieved.

[0094] Example 4 PEIA was introduced into the liquid acetone ABS-ferrite particle dispersion, which was intensively sheared by combined treatment with Ultraturrax and ultrasound according to Table 1. The acetone was removed under reduced pressure, and the film-like residue of the ABS-ferrite composite was crushed and then injection molded to produce a plate-like intermediate.

[0095] Table 2 shows the permittivity ε' and permeability μ' at 800 MHz and the attenuation loss tanδ between filled ABS-gFi130 composites obtained through the dispersion process of ferrite in acetone ABS solution via melt compounding. ε and tan δ μ are compared.

[0096] The ABS-ferrite composites obtained by the dispersion process are characterized by significantly lower values ​​of the real components of the permittivity ε' and magnetic permeability μ' than the ABS-ferrite compounds obtained by conventional melt compounding.

[0097] The decrease in ε′ and μ′ correlates with the decrease in density of the ABS-ferrite composites produced by the dispersion process.

[0098] The decrease in permittivity ε′ and magnetic permeability μ′ of these ABS-ferrite composites is caused by cavities formed by the evaporation of acetone solvent residues during injection molding of the composites.

[0099] However, when the PEIA component is inserted into the acetone ABS-ferrite dispersion, the permittivity ε′, magnetic permeability μ′, and refractive index n are increased simultaneously compared to the composite without PEIA.

[0100] Of particular interest is the reduction in dielectric and magnetic damping losses by introducing micropores into the highly filled ABS-ferrite composite structure. In the presence of the PEIA spacer compound, the loss tangent values ​​are further reduced.

[0101] [Table 2]

[0102] Example 5 To improve the particle distribution and mixing quality of the magnetic particles in the polymer composite, a second magnetic component was used to increase the refractive index, permittivity ε' and / or permeability μ' of the magneto-dielectric polymer system. The filling level c of the primary magnetic component 1 is the second-order component c 2 For c 1 >c 2 It becomes.

[0103] where the average diameter of the primary magnetic filler, d 1 and the average diameter of the secondary component d 2 The difference in size between 1 >>d 2 or d 1 >d 2 The above conditions must be met.

[0104] Next, the permittivity ε', permeability μ', and refractive index n at 400 and 800 MHz of the ternary magnetic filled polymer hybrids without and with the addition of the PEIA spacer compound were compared with each other.

[0105] Figure 6 Hybrid ABS-10Fe 3 O 4 -55Co 2 Z and ABS-10gFi130-59Co 2 The permittivity ε′ and permeability μ′ of Z are significantly increased as a result of adding PEIA, which, in agreement with Equation 1, increases the refractive index and therefore reduces the miniaturization factor of the antenna with the magneto-dielectric substrate.

[0106] The dielectric and magnetic damping losses of the hybrids with PEIA components are tanδ ε = ε” / ε'<0.1 and tan δ μ =μ” / μ'<0.1.

[0107] Example 6 To measure the S11 scattering parameter (return flow attenuation) with a ZVB14 network analyzer, a 9.4 cm long dipole antenna with a resonant frequency of 1335 MHz in air was surrounded by layers of 2 mm thick injection molded plates of pure ABS, ABS-65gFi130 with no additives, ABS-65gFi130-2OMP and ABS-65gFi130-2TSP containing two different POSS compounds, and ABS-65gFi130-2PEIA containing a PEIA spacer additive. The experimental setup used is shown in Figure 7.

[0108] Resonant frequency f of a dipole antenna r The shift in is plotted as a function of frequency and refractive index for selected polymer substrates in FIG.

[0109] The dipole antenna using sample ABS-65gFi130-2PEIA (805) containing the PEIA component shows the largest shift in resonant frequency in air (800) as well as in comparison to samples ABS (801), ABS-65gFi130 without additives (802), ABS-65gFi130-2OMP (803) and ABS-65gFi130-2TSP (804) containing POSS compounds.

[0110] Since the shift of the resonant frequency of the dipole-type antenna to the lower frequency range is correlated with the refractive index of the studied polymer composite material, the miniaturization factor is minimized when using the sample ABS-65gFi130-2PEIA(805) as the antenna substrate with the maximum refractive index according to Eq.

[0111] Example 7 An antenna structure with two dipoles of lengths 10.7 mm and 5.5 mm, with resonant frequencies in air of 1158 MHz and 2022 MHz, was coated with a polyamide elastomer composite consisting of matrix UBE68, ferrite filler gFi130 and PEIA additive using a fused filament fabrication (FFF) 3D printing process. A filament with a diameter of 1.75 mm was produced from the magnetic dielectric polymer composite UBE68-65gFi130-2PEIA, which contains 65% by mass of spinel ferrite and 2% by mass of PEIA. The thickness of the layer material printed on the antenna structure was 3 mm per side.

[0112] From Figure 9, printing the polymer composite material UBE68-65gFi130-2PEIA around both sides of the antenna structure shifts the original resonant frequencies of 1158 and 2022 MHz (900) to the region of 805 and 1295 MHz (901), resulting in a large increase in f r1 * / f r1 = 805 / 1158 approx. 0.69 and f r2 * / f r2 =1295 / 2022 approx. 0.64, which clearly corresponds to a build size reduction of 31% and 36%.

Claims

1. It has soft magnetic properties and an average particle diameter d ５０ A magnetorectifying polymer composite material comprising a matrix of one or more nonpolar polymers containing dispersed particles having a diameter of 0.05 to 10 μm, wherein the soft magnetic particles are surrounded by amphiphilic superbranched spacer molecules, thereby reducing the dielectric decay loss tanδ of the magnetorectifying polymer substrate. ε is less than 0.1, magnetic attenuation loss tanδ μ The refractive index n is less than 0.1, and the refractive index n increases compared to a magnetorelectric polymer composite material that does not contain amphiphilic superbranched spacer molecules, and the refractive index n is defined as follows: [Math 1] (In the formula, ε' is the dielectric constant of the magnetorectifying polymer composite material, and μ' is the permeability of the magnetorectifying polymer composite material.) A magnetorelectric polymer composite material characterized by the following features.

2. The particles having soft magnetic properties comprise a ceramic or metal oxide compound containing elements of cobalt, iron, manganese and / or nickel, and the formula Ba ３ Co ２ Fe ２４ O ４１ of Z-type cobalt hexaferrite, the general formula Ni ａ Zn （１－ａ） Fe ２ O ４ of nickel zinc ferrite and / or magnetite (Fe ３ O ４ ) particles are preferred, the magnetodielectric polymer composite material according to claim 1.

3. The particles having soft magnetic properties have an average particle diameter d ５０ It is a NiZn ferrite-type microscale / submicron spinel ferrite with a particle size of 0.1 to 10.0 μm, or an average particle size d ５０ The formula Ba has a range of 0.1 to 10.0 μm. ３ Co ２ Fe ２４ O ４１ Co ２ It is either a Z-type microscale / submicron hexaferrite, or has an average particle size d. ５０ Formula Fe is 0.05 to 10.0 μm ３ O ４ The magnetorelectric polymer composite material according to claim 1, wherein the magnetorelectric polymer is a submicron / nanoscale magnetite.

4. The particles having soft magnetic properties have different compositions and different average particle diameters d ５０ A mixture comprising the same composition, wherein each of the particles has the same average particle diameter d ５０ The magnetic dielectric polymer composite material according to claim 3, wherein the difference from those with different compositions is at least 1 μm, preferably at least 2 μm, more preferably at least 3 μm.

5. The amphiphilic hyperbranched spacer molecule having a nonpolar group is a functionalized polyethyleneimine, and the nonpolar group is preferably of the formula -CO-C with n≧6. ｎ H ２ｎ＋１ The magnetic dielectric polymer composite material according to any one of claims 1 to 4, wherein the acyl group is preferably an n=16 hexadecanoyl group or an n=18 octadecanoyl group, and forms an amide bond with the primary amino group of polyethyleneimine.

6. The polymer matrix has dielectric decay tanδ ε <0.02, preferably δ ε A magnetorelectric polymer composite material according to any one of claims 1 to 4, comprising one or more nonpolar polymers having a polarity of <0.

01.

7. The nonpolar polymer in the matrix is ​​a polyolefin, preferably a cyclic olefin polymer (COP), a cyclic olefin copolymer (COC), polyethylene (PE), polypropylene (PP), a styrene-containing polymer, preferably polystyrene (PS), high-impact modified polystyrene (HIPS), and acrylonitrile-butadiene-styrene copolymer (ABS), polyoxymethylene (POM), a polyester, preferably polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and polyethylene naphthalate (PEN), polycarbonate (PC), polyphenylene ether (PPE), polyphenylene oxide (PPO), polyphenylene sulfide (PPS), or fluorine-containing polymer. The magnetic dielectric polymer composite material according to any one of claims 1 to 4, wherein the polymer is preferably polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), perfluoro(ethylene-propylene) (FEP) and ethylene-tetrafluoroethylene copolymer (ETFE), a thermoplastic elastomer, preferably polyether block amide (PEBA), a one-component solid silicone elastomer, preferably room temperature crosslinked (RTV) or high temperature crosslinked (HTV) silicone rubber, a liquid two-component silicone rubber (liquid silicone rubber, LSR), preferably polydimethylsiloxane, ethylene-propylene-diene rubber (EPDM), an epoxy resin casting compound (room temperature or heat curing type) and / or an acrylic acid ester-containing epoxy resin.

8. The magnetorelectric polymer composite material according to any one of claims 1 to 4, wherein the individual components are mixed together by compounding, preferably by mixing in an extruder or kneader, or the material is produced by providing a dispersion comprising a solution of at least one nonpolar polymer, particles having soft magnetic properties, and the amphiphilic hyperbranched spacer molecules, and then removing the solvent.

9. The magnetorelectric polymer composite material according to claim 5, comprising 10 to 80% by weight of at least one nonpolar polymer, 20 to 90% by weight of the particles having soft magnetic properties, and 0.1 to 10% by weight of amphiphilic hyperbranched polyethyleneimine.

10. A magnetorelectric polymer composite material according to any one of claims 1 to 4, comprising an antenna operating in a frequency range of 50 MHz to 4 GHz.

11. A magnetorelectric polymer composite material according to any one of claims 1 to 4, which can be processed by a plastic molding process, preferably by injection molding, injection compression molding, compression molding or extrusion, or by a resin casting process.

12. A magnetic dielectric polymer composite material according to any one of claims 1 to 4, having a form suitable for 3D printing, preferably a filament, pellet, powder, liquid resin, or liquid silicone elastomer.

Images