Electromagnetic converter with a polymer element based on a mixture of polyisocyanate and isocyanate functional prepolymer and a compound with at least two isocyanate reactive hydroxyl groups

ELECTROMAGNETIC CONVERTER WITH A POLYMER ELEMENT BASED ON A MIXTURE OF POLYISOCYANATE AND ISOCYANATE FUNCTIONAL PREPOLYMER AND A COMPOUND WITH AT LEAST TWO ISOCYANATE REACTIVE HYDROXYL GROUPS}

The present invention relates to an electromechanical converter, in particular an electromechanical sensor, an actuator, comprising a polymer element obtainable from a reaction mixture comprising a polyisocyanate, a polyisocyanate prepolymer and a compound having at least two isocyanate-reactive hydroxy groups; / or about the generator. The invention also relates to a method for manufacturing said electromechanical converter and to the use of said polymer element as actuator, sensor and/or generator. The invention also relates to an electronic and/or electrical device comprising the electromechanical converter according to the invention, and to the use of the electromechanical converter according to the invention in an electronic and/or electrical device.

Electromechanical converters convert electrical energy into mechanical energy and vice versa. Thus, the electromechanical converter can be used as a sensor, actuator and/or generator.

The basic structure of such a converter is based on a layer of electroactive polymer coated on both sides with electrodes. An electroactive polymer is understood as a polymer that changes in its volume and/or its shape depending on a voltage applied to it, and/or as a polymer capable of generating a voltage through a change in volume and/or its shape.

WO 01/06575 A1 discloses, for example, that silicone elastomers, acrylic acid elastomers, polyurethanes, thermoplastic elastomers, copolymers comprising polytetrafluoroethylene, fluorinated elastomers, and polymers comprising silicone and acrylic acid groups are described above. It is disclosed that the electromechanical properties of

The unpublished European patent application EP08013648.4 discloses an electromechanical converter produced from polyisocyanates and/or polyisocyanate prepolymers and diamino-functional compounds. The unpublished European patent application EP08018936.8 discloses an electromechanical converter produced from a solution of one or more polyurethanes in an organic solvent. These systems have the disadvantage that their coating possibilities are very limited due to the high content of organic solvents, due to the various requirements that must be complied with from a health and safety point of view, for example to protect workers and to prevent ignition agents. Also, for ecological reasons, a system free of large amounts of organic solvents is desirable.

In addition, conventional polymers used in electromechanical converters often have adverse properties that can adversely affect the functional capabilities of the electromechanical converter. These adverse properties include poor mechanical and other properties, particularly adverse elongation properties, poor insulation behavior, particularly low breakthrough field strength strength and high electrical conductivity, poor machinability and high material cost. In particular, it is impossible to achieve the desired combination of properties in one material using polymers, such as silicones commonly used in electromechanical converters. Even the polyurethane producing converters used in EP08013648.4 and EP08018936.8 show poorer optimal mechanical properties, which is because the polyurethanes have linear polymer chains, in particular resulting in less optimal elastomer properties. Because.

Accordingly, it was an object of the present invention to provide an electromechanical converter which exhibits improved properties and overcomes the disadvantages of known electromechanical converters.

Within the scope of the present invention, the object is an electromechanical converter containing a polymer element obtainable from a reaction mixture comprising a polyisocyanate, a polyisocyanate prepolymer and at least two isocyanate-reactive hydroxyl groups, in particular hydroxyl group-containing polymers. achieved by Definitions and differences between the terms "polyisocyanate" and "polyisocyanate prepolymer" are provided herein below. In each case, there are compounds containing at least two free isocyanate groups.

Accordingly, the present invention contains at least two electrodes and at least one electroactive polymer component located between these two electrodes and in particular in contact with the at least one electrode, said polymer component according to the invention comprising the following components

A) polyisocyanate

B) polyisocyanate prepolymer

C) compounds having at least two isocyanate-reactive hydroxy groups

An electromechanical converter obtainable from a reaction mixture comprising a film-forming reaction mixture is provided.

According to the invention, as polyisocyanates and component A), such as 1,4-butylene diisocyanate, 1,6-hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), 2,2,4- and / or 2,4,4-trimethylhexamethylene diisocyanate, the isomeric bis-(4,4'-isocyanatocyclohexyl)methane, or mixtures thereof having any desired isomeric content, 1,4-cyclohex silane diisocyanate, 4-isocyanatomethyl-1,8-octane diisocyanate (nonane triisocyanate), 1,4-phenylene diisocyanate, 2,4- and/or 2,6-toluylene diisocyanate, 1,5-naphthylene diisocyanate, 2,2'- and/or 2,4'- and/or 4,4'-diphenylmethane diisocyanate, 1,3- and/or 1,4-bis-( 2-isocyanatoprop-2-yl)-benzene (TMXDI), 1,3-bis(isocyanatomethyl)-benzene (XDI), One Suitable are alkyl 2,6-diisocyanatohexanoates (lysine diisocyanates) containing alkyl groups having from to 8 carbon atoms, and mixtures thereof. Also suitable structural units of component A) are compounds based on the above diisocyanates and containing uretdione, isocyanurate, biureth, iminooxadiazinedione or oxadiazinetrione structures.

The polyisocyanate prepolymers which can be used as component B) can be obtained by reaction of at least one diisocyanate with at least one hydroxy-functional polyol (in particular a polymer polyol), optionally with the addition of catalysts as well as auxiliary substances and additives. have. In addition, components for chain extension, such as primary and/or secondary amino groups (NH₂- and/or NH-functional group component) may be used further for the formation of the polyisocyanate prepolymer.

Within the scope of the present invention, component C) may theoretically be a compound having at least two isocyanate-reactive hydroxy groups. For example, component C) may be a polyol having at least two isocyanate-reactive hydroxy groups.

Within the scope of the present invention, the term "a(a)" in relation to components A), B) and C) is used as the indefinite article and not as a number.

Polymeric elements made from the components according to the invention have good mechanical strength and high elasticity. In addition, the polymer element additionally has good electrical properties, such as break-through field strength and permittivity, and thus can be advantageously used in electromechanical converters.

When applying a mechanical load to the converter, the converter deforms (eg, along its thickness), and a strong electrical signal can be detected at the electrode. By doing so, mechanical energy is converted into electrical energy. As a result, the converter according to the invention can be used both as a generator and as a sensor.

On the other hand, by using the reverse action (ie the conversion of electrical energy into mechanical energy), the converter according to the invention can equally be used as an actuator.

In an embodiment of the electromechanical converter according to the invention, component A) in the reaction mixture has a functionality of at least 2 and has a uretdione, isocyanurate, biureth, iminooxadiazinedione or oxadiazinetrione structure It may be a diisocyanate-based polyisocyanate or mixtures thereof, preference is given in particular to component A) having an isocyanurate structure.

In an embodiment of the electromechanical converter according to the invention, component A) may be a polyisocyanate or a polyisocyanate mixture, having an average NCO functionality of 2 to 4, with isocyanate groups bonded alone, either aliphatically or cycloaliphatically. Preferred have a mixture average NCO functionality of 2 to 4, preferably 2 to 2.6 and more preferably 2 to 2.4, uretdione, isocyanurate, biuret, iminooxadiazinedione or oxadiazinetrione Polyisocyanates or polyisocyanate mixtures of the above-mentioned type having the structure and mixtures thereof are provided.

More preferably, in addition to the above-mentioned mixtures of diisocyanates, hexamethylene diisocyanate, isophorone diisocyanate or polyisocyanates based on the isomer bis-(4,4'-isocyanato-cyclohexyl)methane are used in component A ) can be used as

Polyisocyanate prepolymers as component B) are preferably obtainable from the reaction of polymeric polyols with aliphatic diisocyanates. Preferred as component B) are polyisocyanate prepolymers based on polypropylene glycol as polyol and based on hexamethylene diisocyanate as aliphatic diisocyanate.

In addition, according to the invention, the hydroxy-functional polymer polyols for the reaction on the polyisocyanate prepolymer B) are, for example, polyester polyols, polyacrylate polyols, polyurethane polyols, polycarbonate polyols, polyether polyols, polyester polyacrylate polyols, polyurethane polyacrylate polyols, polyurethane polyester polyols, polyurethane polyether polyols, polyurethane polycarbonate polyols and/or polyester polycarbonate polyols. The above compounds can be used individually or in any mixture with one another for the preparation of polyisocyanate prepolymers.

Suitable polyester polyols for the preparation of the polyisocyanate prepolymer B) are polycondensation products of diols as well as optional triols and tetraols, and polycondensation products of dicarboxylic acids as well as optional tricarboxylic acids and tetracarboxylic acids It may be a product of a polymerization, or a product of a polycondensation of a hydroxycarboxylic acid or lactone. It is also possible to use the corresponding polycarboxylic anhydrides or polycarboxylic acid esters of the corresponding lower alcohols for the production of polyesters instead of the free polycarboxylic acids.

Examples of suitable diols include ethylene glycol, butylene glycol, diethylene glycol, triethylene glycol, polyalkylene glycols (eg polyethylene glycol), also 1,2-propanediol, 1,3-propanediol, 1,3- butanediol, 1,4-butanediol, 1,6-hexanediol and isomers, neopentyl glycol or hydroxypivalic acid neopentyl glycol esters or mixtures thereof, preferred are 1,6-hexanediol and isomers, 1,4 -butanediol, neopentyl glycol and hydroxypivalic acid neopentyl glycol esters. In addition, polyols such as trimethylolpropane, glycerol, erythritol, pentaerythritol, trimethylolbenzene or trishydroxyethyl isocyanurate or mixtures thereof may be used.

As dicarboxylic acids, phthalic acid, isophthalic acid, terephthalic acid, tetrahydrophthalic acid, hexahydrophthalic acid, cyclohexanedicarboxylic acid, adipic acid, azelaic acid, sebacic acid, glutaric acid, tetrachlorophthalic acid, maleic acid, fumaric acid, Itaconic acid, malonic acid, suberic acid, 2-methylsuccinic acid, 3,3-diethylglutaric acid and/or 2,2-dimethylsuccinic acid may be used. The corresponding anhydrides may also be used as acid source.

The average functionality of the esterified polyol is provided to be at least 2, and monocarboxylic acids such as benzoic acid and hexanecarboxylic acid can also be used additionally simultaneously.

Preferred acids are aliphatic or aromatic acids of the type mentioned above. In particular, adipic acid, isophthalic acid and phthalic acid are preferred.

Hydroxycarboxylic acids which can be used simultaneously as reactants in the preparation of polyester polyols having terminal hydroxyl groups are, for example, hydroxycaproic acid, hydroxybutyric acid, hydroxydecanoic acid or hydroxystearic acid or mixtures thereof. Suitable lactones include caprolactone, butyrolactone or homologues or mixtures thereof. Caprolactone is preferred.

Likewise, hydroxyl-group-containing polycarbonates, such as polycarbonate polyols, preferably polycarbonate diols, can be used for the preparation of the polyisocyanate prepolymer B). For example, these compounds have a number-average molecular weight M of 400 g/mol to 8000 g/mol, preferably 600 g/mol to 3000 g/mol._ncan have They can be obtained by reaction of a carbonic acid derivative (such as diphenyl carbonate, dimethyl carbonate or phosgene) with a polyol (preferably a diol).

Examples of diols suitable for this purpose include ethylene glycol, 1,2- and 1,3-propanediol, 1,3- and 1,4-butanediol, 1,6-hexanediol, 1,8-octanediol, neopentyl Glycol, 1,4-bishydroxymethylcyclohexane, 2-methyl-1,3-propanediol, 2,2,4-trimethyl-1,3-pentanediol, dipropylene glycol, polypropylene glycol, dibutylene glycols, polybutylene glycols, bisphenol A or lactone-modified diols of the type mentioned above or mixtures thereof.

The diol component preferably contains 40% to 100% by weight of hexanediol, preferably 1,6-hexanediol and/or a hexanediol derivative. The hexanediol derivatives are based on hexanediol and may contain ester or ether groups in addition to terminal OH groups. These derivatives are obtainable, for example, by reaction of hexanediol with a surplus of caprolactone, or by esterification with hexanediol itself, to give di- or tri-hexylene glycol. Within the scope of the present invention, these and other components are selected in a known manner so that the total weight % is less than 100% by weight, in particular the total weight% is 100% by weight.

The hydroxyl-group-containing polycarbonates, in particular polycarbonate polyols, are preferably linear in structure.

Likewise, polyether polyols can be used for the preparation of polyisocyanate prepolymers B). For example, polytetramethylene glycol polyether obtainable by polymerization of tetrahydrofuran by cationic ring opening is suitable. Likewise suitable polyether polyols may be addition products of di- or poly-functional starting molecules with styrene oxide, ethylene oxide, propylene oxide, butylene oxide and/or epichlorohydrin. As suitable starting molecules, for example water, butyl diglycol, glycerol, diethylene glycol, trimethylolpropane, propylene glycol, sorbitol, ethylenediamine, triethanolamine or 1,4-butanediol or mixtures thereof can be used.

Preferred components for the preparation of the polyisocyanate prepolymer B) are polypropylene glycol, polytetramethylene glycol polyether and polycarbonate polyols or mixtures thereof, with polypropylene glycol being particularly preferred.

400 number-average molecular weight M from g/mol to 8000 g/mol, preferably from 400 g/mol to 6000 g/mol and particularly preferably from 600 g/mol to 3000 g/mol_nPolymer polyols having This polymer polyol preferably has an OH function of from 1.5 to 6, more preferably from 1.8 to 3 and most preferably from 1.9 to 2.1.

In addition to the above polymeric polyols, also short-chain polyols can be used for the preparation of the polyisocyanate prepolymer B). For example, ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,3-butylene glycol, cyclohexanediol, 1,4-cyclo Hexanedimethanol, 1,6-hexanediol, neopentyl glycol, hydroquinone dihydroxyethyl ether, bisphenol A (2,2-bis(4-hydroxyphenyl)propane), hydrogenated bisphenol A (2,2-bis( It is possible to use 4-hydroxycyclohexyl)-propane), trimethylolpropane, trimethylolethane, glycerol or pentaerythritol or mixtures thereof.

Also, ester diols in the above molecular weight range, such as α-hydroxybutyl-ε-hydroxy-caproic acid ester, ω-hydroxyhexyl-γ-hydroxybutyric acid ester, adipic acid (β-hydroxyethyl) ester or Terephthalic acid bis(β-hydroxyethyl) ester is suitable.

Furthermore, monofunctional isocyanate-reactive hydroxyl-group-containing compounds can also be used for the preparation of the polyisocyanate prepolymer B). Examples of such monofunctional compounds include ethanol, n-butanol, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, tripropylene glycol mono Methyl ether, dipropylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol monobutyl ether, tripropylene glycol monobutyl ether, 2-ethylhexanol, 1-octanol, 1-dodecanol or 1-hexadecane all or mixtures thereof.

In an embodiment of the invention, for the preparation of the polyisocyanate prepolymer B), the diisocyanate is mixed with a polyol in a ratio of isocyanate groups to hydroxyl groups (NCO/OH ratio) of 2:1 to 20:1, such as 8:1. It is possible to react with In doing so, urethane and/or allophanate structures may be formed. The content of unreacted polyisocyanate can then be separated. For this purpose, for example, thin-layer distillation can be used, and a product with low residual monomers is obtained, for example having a residual monomer content of 1% by weight or less, preferably 0.5% by weight or less, more preferably 0.1% by weight or less. The reaction temperature may be 20 °C to 120 °C, preferably 60 °C to 100 °C. Stabilizers such as benzoyl chloride, isophthaloyl chloride, dibutyl phosphate, 3-chloropropionic acid or methyl tosylate may optionally be added during preparation.

Furthermore, for chain extension in the preparation of polyisocyanate prepolymer B) NH₂- and/or NH-functional group components may optionally be used.

Suitable components according to the invention for chain extension are organic diamines or polyamines. For example, ethylenediamine, 1,2-diaminopropane, 1,3-diaminopropane, 1,4-diaminobutane, 1,6-diaminohexane, isophoronediamine, 2,2,4- and 2, It is possible to use isomer mixtures of 4,4-trimethylhexamethylenediamine, 2-methylpentamethylenediamine, diethylenetriamine, diaminodicyclohexylmethane or dimethylethylenediamine or mixtures thereof.

In addition, compounds containing secondary amino groups in addition to primary amino groups, or OH groups in addition to amino groups (primary or secondary) can also be used for the preparation of the polyisocyanate prepolymer B). Examples thereof include primary/secondary amines such as diethanolamine, 3-amino-1-methylaminopropane, 3-amino-1-ethylaminopropane, 3-amino-1-cyclohexylaminopropane, 3-amino -1-methylaminobutane, alkanolamines such as N-aminoethylethanolamine, ethanolamine, 3-aminopropanol, neopentanolamine. For chain termination, amines with groups reactive towards isocyanates such as methylamine, ethylamine, propylamine, butylamine, octylamine, laurylamine, stearylamine, isononyloxypropylamine, dimethylamine, diethyl amine, dipropylamine, dibutylamine, N-methylaminopropylamine, diethyl(methyl)aminopropylamine, morpholine, piperidine or suitable substituted derivatives thereof, amides of diprimary amines- Amines and monocarboxylic acids, monoketims of diprimary amines, primary/tertiary amines such as N,N-dimethylaminopropylamine are commonly used.

The polyisocyanate prepolymers used according to the invention as component B), or mixtures thereof, may preferably have an average NCO functionality of from 1.8 to 5, more preferably from 2 to 3.5, and most preferably from 2 to 2.5. have.

According to the invention, components A) and B) can preferably first be mixed with each other, and then the mixture of A) and B) can be reacted with C).

In a further embodiment, component C) may be a polyamine or polyol having at least two isocyanate-reactive hydroxy groups. Preferably, polymer polyols can be used as component C). It is also preferred according to the invention that component C) is a polymer with polypropylene glycol having 2 to 4 hydroxy groups, most preferably 2 to 3 hydroxy groups.

According to the invention, as component C) hydroxy-functional groups can be used, in particular polymers, polyols, such as polyether polyols. For example, as obtainable by polymerization of tetrahydrofuran by cationic ring opening, polytetramethylene glycol polyether is suitable. Likewise suitable polyether polyols may be addition products of styrene oxide, ethylene oxide, propylene oxide, butylene oxide and/or epichlorohydrin, added together with di- or poly-functional starting materials. Suitable starting molecules that can be used are, for example, water, butyl diglycol, glycerol, diethylene glycol, trimethylolpropane, propylene glycol, sorbitol, ethylenediamine, triethanolamine or 1,4-butanediol or mixtures thereof.

According to the invention, it is preferred that the polymer polyols from C) have a particularly narrow molecular weight distribution, ie a polydispersity of 1.0 to 1.5 (PD = Mw/Mn) and/or more than 1.9 OH functions. Preferably, the polyether polyol has a polydispersity of 1.0 to 1.5, and more than 1.9 OH functions, more preferably more than 1.95 or 1.95 OH functions.

Said polyether polyols can be prepared in a manner known per se, in particular by alkoxylation of suitable starting molecules using double metal cyanide catalysts (DMC catalysts). Such methods are described, for example, in patent US 5,158,922 and published patent EP 0 654 302 A1.

The reaction mixture for the polymer component according to the invention can be obtained by mixing the components A), B) and C). The ratio of isocyanate-reactive hydroxy groups to free isocyanate groups is preferably from 1:1.5 to 1.5:1, more preferably from 1:1.02 to 1:0.95.

In order to introduce branching or crosslinking into the polymer element, at least one of components A), B) or C) preferably has at least 2.0, preferably at least 2.5, preferably at least 3.0 functional groups. Functional groups refer to the average number of NCO groups per molecule in the case of components A) and B) or, in the case of component C), the average number of OH groups per molecule. This branching or crosslinking results in better mechanical properties and better elastomeric properties, in particular also better elongation properties, for the intended use as electromechanical converters.

Within the scope of the present invention, the polymer element may be a polymer layer, in particular a polymer film, a polymer foil or a polymer coating. For example, the polymer layer may have a layer thickness of 0.1 μm to 1500 μm, such as 1 μm to 500 μm, in particular 5 μm to 200 μm, preferably 10 μm to 100 μm.

The polymer element according to the invention may advantageously have good mechanical strength and high elasticity. In particular, the polymer element according to the invention may have a maximum tension of at least 0.2 MPa, in particular of from 0.4 MPa to 50 MPa, and a maximum elongation of at least 250%, in particular of at least 350%. In addition, the polymer element according to the invention has a tensile strength of 0.1 MPa to 1 MPa, such as 0.1 MPa to 0.8 MPa, in particular 0.1 MPa to 0.3 MPa, in the range of in-service elongation of 100% to 200% (measured according to DIN 53504). can have Furthermore, the polymer element according to the invention may have a modulus of elasticity of 0.1 MPa to 10 MPa, such as 0.2 MPa to 5 MPa, at an elongation of 100% (measured according to DIN EN 150 672 1-1).

In addition, the polymer element according to the invention may advantageously have good electrical properties, and these properties may be measured for breakthrough field strength according to ASTM D 149 and dielectric constant according to ASTM D 150.

Also, the present invention

- manufacturing two or more electrodes,

- the following ingredients

A) polyisocyanate

B) a polyisocyanate prepolymer and

C) compounds having at least two isocyanate-reactive hydroxy groups

A polymer component is prepared by reaction of a reaction mixture comprising:

- positioning the polymer element between the two electrodes,

A method of manufacturing an electromechanical converter according to the present invention is provided.

In particular, a polymeric element may be positioned between two electrodes such that the polymeric element is in contact with one or more electrodes.

Within the scope of embodiments of the present invention, an electroactive polymer element may be positioned between two electrodes such that the electrode opposite the polymer element is adjacent to the polymer element. For example, the polymer element may be coated on both sides with an electrode.

Within the scope of a preferred embodiment of the process according to the invention, the polymer component can be prepared by application of the reaction mixture to one or more electrodes, and reaction of the reaction mixture. The reaction mixture may be applied, for example, by knife application, coating, pouring, spin coating, spraying or extrusion. Likewise, within the scope of the present invention, it is possible to manufacture the electrodes and polymer elements in separate steps and then connect them together.

Within the scope of a preferred embodiment of the process according to the invention, the reaction mixture is dried and/or tempered. Drying can take place in a temperature range of 0° C. to 200° C., for example for 0.1 minutes to 48 hours, in particular for 6 hours to 18 hours. Tempering may take place, for example, in a temperature range of 80° C. to 250° C., for example for 0.1 minutes to 24 hours.

In an embodiment of the process according to the invention, the equivalent ratio of isocyanate groups from B) to isocyanate groups from A) used is at least 1:10 and at most 10:1, more preferably at least 1:5 and at most 5:1. and most preferably 1:3 or more and 3:1 or less. The polymer component prepared in the proportions selected above for the reaction mixture can then have particularly advantageous mechanical and electrical properties.

Until substantial crosslinking and curing of the mixture of A), B) and C) is achieved, the rate at 23° C. is typically from 1 second to 300 minutes, preferably from 1 minute to 20 minutes, more preferably from 1 minute to It can be 10 minutes. Curing may be accelerated by a catalyst. In a preferred embodiment, at least 50 mol % of the isocyanate-reactive groups for curing components A) and B) are polyether polyols. Within the scope of a more preferred embodiment of the present invention, components A) and B) are cured with polyether polyol alone, and most preferably with polypropylene glycol alone.

Based on the final reaction mixture of A), B), C) and optional further components, the preferred amounts by weight are:

A) 1 to 30 parts by weight, preferably 4 to 20 parts by weight,

B) 1 to 50 parts by weight, preferably 25 to 40 parts by weight,

C) 10 to 70 parts by weight, preferably 30 to 65 parts by weight, and

Optionally 0 to 50 parts by weight, preferably 0 to 20 parts by weight of further auxiliary substances, added components or additives. In each case, the above-mentioned parts by weight are such that the sum of all said parts by weight is 100.

On the other hand, the reaction mixture comprising components A), B) and C) can be applied directly to the electrode and cured thereon. On the other hand, it is possible to first prepare a film or foil from the reaction mixture, and optionally fully cure the film or foil, and then combine it with the electrode. In doing so, an adhesive may be used, or the adhesiveness of its reaction mixture itself may be used.

The film-forming reaction mixture according to the invention can be applied by any application method known per se, which can be made, for example, by knife application, coating, pouring, spin coating, spraying or extrusion.

In addition to components A), B) and C), the reaction mixture may further comprise auxiliary substances and additives. Examples of such auxiliary substances and additives include crosslinking agents, thickeners, cosolvents, thixotropic agents, stabilizers, antioxidants, light stabilizers, emulsifiers, surfactants, adhesives, plasticizers, waterproofing agents, pigments, fillers and flow enhancers ( flow improvers).

In addition to components A), B) and C), the reaction mixture may also additionally comprise fillers. The filler may, for example, control the dielectric constant of the polymer element. Preferably, the reaction mixture comprises a filler for increasing the permittivity, such as a filler having a high permittivity. Examples of such fillers are ceramic fillers, in particular barium titanate, titanium dioxide and piezoelectric ceramics such as quartz, lead zirconium titanate, in addition to organic fillers, in particular organic fillers with high electrical polarizability, such as phthalocyanine.

Furthermore, by including an electrically conductive filler below the percolation threshold, also a high permittivity can be achieved. Examples thereof are carbon black, graphite, single-walled or multi-walled carbon nanotubes, electrically conductive polymers such as polythiophene, polyaniline or polypyrrole, or mixtures thereof. Of particular interest in this regard are those of the carbon black type, which exhibit a surface coating, thus increasing the permittivity at low concentrations below the percolation threshold, but nevertheless increasing the conductivity of the polymer.

Also, within the scope of the present invention, additives may be added to increase the dielectric constant and/or the electrical break-through field strength after the formation of the film. This can be done, for example, by making one or more additional layers, or by permeating the additive into the polymeric element (eg by diffusing the additive into the polymeric element).

In addition, multi-layer application of the reaction mixture is additionally possible with optional intermediate drying steps.

Drying and fixing of the reaction mixture can take place at a temperature of 30° C., preferably between 10° C. and 200° C. In doing so, the coated substrate can be carried on a heated surface, for example by means of a roller. Application and drying may be performed discontinuously or continuously, respectively. The whole process is preferably continuous.

The polymer element according to the invention is provided in further functional layers, such as conductive layers, barrier layers to solvents and gases and/or adhesive layers. This can be done on one or both sides, in one layer or in multiple overlapping layers, by coating the entire surface or part of the surface of the polymer element.

Suitable base materials for the production of polymeric films from the reaction mixture are, in particular, glass, release papers, foils and plastics, the polymeric films resulting therefrom, which can optionally be removed in a simple manner.

Processing of the individual layers of the reaction mixture can be carried out by pouring or knife application, carried out manually or by machine. Likewise, printing, screen printing, spraying and dipping are possible process technologies.

After crosslinking, the polymer element in the form of a polymer film, polymer foil or polymer coating according to the invention has a layer of 0.1 μm to 1500 μm, such as 1 μm to 500 μm, in particular 5 μm to 200 μm, preferably 10 μm to 100 μm. may have a thickness.

In addition, the present invention includes the following components

A) polyisocyanate

B) a polyisocyanate prepolymer and

C) compounds having at least two isocyanate-reactive hydroxy groups

The use of a polymer element obtainable from a reaction mixture comprising

The invention also provides an electronic and/or electrical device, in particular a structural component, an automated machine, device or component, comprising an electromechanical converter according to the invention.

The invention also provides for the use of the electromechanical converter according to the invention in electronic and/or electrical devices, in particular actuators, sensors and/or generators. Advantageously, the invention relates to electromechanical and electroacoustic fields, in particular mechanical vibration (energy harvesting), acoustics, ultrasound, medical diagnostics, acoustic microscopy, medical sensor systems, in particular pressure, force and/or strain sensors. In the field of obtaining energy from systems, robotics and/or communication technology, it can be carried out in a number of very diverse applications. Typical examples of these include fiber optics, pyroelectric detectors, capacitors and conditioning systems and "intelligent" floors, in addition to systems that convert water-wave energy, particularly ocean wave energy, into electrical energy. pressure sensors, electroacoustic converters, microphones, loudspeakers, vibration transducers, optical deflectors, membranes, and regulators.

To construct the converter according to the invention, the polymer element according to the invention can be coated on both sides with electrodes, for example as described in WO 01/06575. This basic structure can be advantageously used in a wide variety of configurations to create sensors, actuators and/or generators. Advantageously, the polymer element for an electromechanical converter according to the invention has particularly good mechanical and electrical properties. The electromechanical converter according to the present invention can be used in many different applications.

Further, the present invention is illustrated by, but not limited to, the examples provided below.

<b><u>Example</u></b><b><u>:</u></b>

Unless otherwise indicated, all percentages are by weight.

Unless otherwise indicated, all analytical measurements are based on measurements at a temperature of 23°C.

Conversely, unless otherwise indicated, the NCO content is determined volumetric according to DIN-EN ISO 11909.

The viscosities indicated by the rotary viscometer according to DIN 53019 at 23° C. were measured using a rotary viscometer from Anton Paar Germany GmbH, Helmus-Hirs-Street 6, 73760 Ostfildern, Germany. The incorporation of the filler into the dispersion according to the invention was carried out using a Speedmixer (Model 150 FV from Hauschild &amp; Co. KG, Watercamp 1, Hamm 59075, Germany). carried out.

The film layer thickness was measured using a mechanical contact probe from Dr. Johannes Heidenhain GmbH, Dr. Johannes-Heidenhain-Street 5, 83301 Traunleut, Germany. Test specimens were measured at three different locations, and this average value was used as a representative average value.

Tensile testing according to DIN 53 504 by a tensile testing machine from Zwick (Model No. 1455), equipped with a load cell for a total measuring range of 1 kN, at a pulling speed of 50 mm/min. was performed. S2 tensile rods were used as test specimens. Each measurement was performed on three test samples prepared in the same manner, and the average value of the obtained data was used for evaluation. In particular, for this purpose, not only the tensile strength in [MPa] and the highest elongation in [%], but also the tensile in [MPa] at elongations of 100% and 200% were measured.

On the S2 rod of the sample being tested, the permanent elongation was determined by means of a Zwicki tensile testing machine from Zwick/Roell, equipped with a load cell for a total measuring range of 50 N. In this measurement, the sample is stretched to n*50% at a rate of 50 mm/min, and when this deformation is reached, the sample is relaxed with a force = 0 N, and then the remaining elongation is measured. After that, the next measurement cycle was immediately started with n = n + 1, and the value of n was increased until the sample was torn. Only values of 50% strain were measured here.

Likewise, creep was measured on a Twiki tensile testing machine, and the apparatus corresponded to the test for permanent elongation measurement. The test specimen used in this case is 60 x 10 mm² A sample in the form of a strip of area, which was clamped with a clamp spacing of 50 mm. After a very rapid deformation to 55 mm, this deformation was held constant for 30 minutes, during which time the force progression was measured. Based on the initial value immediately after deformation to 55 mm, the percentage of creep force after 30 minutes was reduced.

Measuring system (measuring bridge) from Novocontrol Technologies GmbH &amp; Co. KG, Obererbacher Strasse 9, Hundsangen 56414, Germany A) Using an analyzer, measuring body: ZGS active sample cell test contact), the measurement of the dielectric constant according to ASTM D 150-98 was performed on a test specimen having a diameter of 20 mm. 10⁷ Hz to 10^-2 The frequencies in the Hz range were tested. As a measure of the permittivity of the tested material, 10 of the actual component^-2 The permittivity in Hz was chosen.

High-voltage supply model LNC 20000-3pos from Heinzinger, 4 Anton-Jacob-Street, 83026 Rosenheim, Germany, and DKI (Deutsche Kunststocktitut 6 Schklossgarten Street, Darmstadt, Germany 64289) Breakthrough field strength according to ASTM D 149-97a was measured using the sample holder configured inside the Deutsches Kunststoffinstitut). This sample holder made contact with a polymer sample of uniform thickness with only a small mechanical preload and prevented the user from coming into contact with voltage. In this system, the voltage is statically increased (in silicone oil for insulation against burst discharge in air) over the polymer film without a preceding load until an electrical break-through occurs through the foil. The measurement result is the voltage (in [V/μm]) reached through the polymer film based on the thickness.

Substances and abbreviations used:

Desmodur^&amp;#174;(Desmodur^&amp;#174;) N 3300: isocyanurate based on hexamethylene diisocyanate, NCO content of 21.8 ± 0.3% (according to DIN EN ISO 11 909), viscosity at 23 ° C of 3000 ± 750 mPa s, from Leverkusen, Germany Bayer MaterialScience AG (Component A)

Desmodur^&amp;#174;XP 2410: low-viscosity, aliphatic polyisocyanate resin based on hexamethylene diisocyanate, NCO content of 23.5 ± 0.5% by weight (DIN EN ISO 11 909), viscosity at 23° C. of 730 ± 100 mPa·s, Germany Buyer MaterialScience AG, Leverkusen (component A)

Desmodur^&amp;#174;XP 2599:Ether-group-containing prepolymers based on aliphatic, hexamethylene-1,6-diisocyanate (HDI), isocyanate content of 6±0.5% (DIN EN ISO 11 909), 23° C. of 2500±500 mPa·s Viscosity at, Buyer MaterialScience AG, Leverkusen, Germany (component B)

DBTDL: Dibutyltin dilaurate from E-Merck KGaA, 250 Frankfurter Street, Darmstadt, D-64293, Germany

<b><u>Example</u></b><b><u> 1</u></b>

Preparation of diisocyanate-functional polyisocyanate prepolymers as component B)

1300 g of hexamethylene-1,6-diisocyanate (HDI), 1.3 g of benzoyl chloride and 1.3 g of para-toluenesulfonic acid methyl ester were placed in a 4 liter four-necked flask with stirring. Within 3 hours, 1456 g of a bifunctional polypropylene glycol-polyether, having a number-average molecular weight of 2000 g/mol, was added at 80° C., followed by stirring at the same temperature for 1 hour. The excess HDI was then distilled off at 130° C. and 0.1 torr by thin film distillation, and 1 g of chloropropionic acid was found in the receiver. The resulting NCO polymer had an NCO content of 3.23% and a viscosity (25° C.) of 1650 mPas.

<b><u>comparison </u></b><b><u>Example</u></b><b><u></u></b><b><u>C1</u></b><b><u>:</u></b>

Preparation of polymer elements not according to the invention

The raw materials used were not individually degassed. In a polypropylene beaker with a speedmixer at 3000 rpm per minute over 3 minutes, 10 g of Desmodur XP 2599 (component B) had a number-average molecular weight of 6000 g/mol and an ethylene oxide unit content of 0 weight % trifunctional polypropylene glycol-polyethylene glycol-polyether (component C) 28.1 g and DBTDL 0.028 g. From the still liquid reaction mixture, a film with a wet layer thickness of 1 mm was applied manually to the glass plate by means of a knife. After preparation, all films were dried overnight in a drying cabinet at 80° C. and then tempered at 120° C. for 5 minutes. After tempering, the film could be easily and manually separated from the glass plate.

<b><u>comparison </u></b><b><u>Example</u></b><b><u></u></b><b><u>C2</u></b><b><u>:</u></b>

Preparation of polymer elements not according to the invention

The raw materials used were not individually degassed. 10 g of Desmodur XP 2599 (component B) in a polypropylene beaker with a speedmixer at 3000 rpm per minute over 3 minutes having a number-average molecular weight of 4000 g/mol and an ethylene oxide unit content of 0 weight % difunctional polypropylene glycol-polyethylene glycol-polyether (component C) 28.06 g and DBTDL 0.028 g. From the still liquid reaction mixture, a film with a wet layer thickness of 1 mm was applied manually to the glass plate by means of a knife. After preparation, all films were dried overnight in a drying cabinet at 80° C. and then tempered at 120° C. for 5 minutes. After tempering, the film could be easily and manually separated from the glass plate.

<b><u>comparison </u></b><b><u>Example</u></b><b><u></u></b><b><u>C3</u></b><b><u>:</u></b>

Preparation of polymer elements not according to the invention

The raw materials used were not individually degassed. In a polypropylene beaker with a speedmixer at 3000 rpm per minute over 3 minutes, 3.91 g of Desmodur N3300 (component A) has a number-average molecular weight of 4000 g/mol and an ethylene oxide unit content of 0% by weight Phosphorus difunctional polypropylene glycol-polyethylene glycol-polyether (component C) 39.88 g and DBTDL 0.12 g. From the still liquid reaction mixture, a film with a wet layer thickness of 1 mm was applied manually to the glass plate by means of a knife. After preparation, all films were dried overnight in a drying cabinet at 80° C. and then tempered at 120° C. for 5 minutes. After tempering, the film could be easily and manually separated from the glass plate.

<b><u>comparison </u></b><b><u>Example</u></b><b><u></u></b><b><u>C4</u></b><b><u>:</u></b>

Preparation of polymer elements not according to the invention

The raw materials used were not individually degassed. In a polypropylene beaker with a speedmixer at 3000 rpm per minute over 3 minutes, 3.58 g of Desmodur XP2410 (component A) has a number-average molecular weight of 6000 g/mol and an ethylene oxide unit content of 0% by weight 39.88 g of phosphorus trifunctional polypropylene glycol-polyethylene glycol-polyether (component C) and 0.12 g of DBTDL. From the still liquid reaction mixture, a film with a wet layer thickness of 1 mm was applied manually to the glass plate by means of a knife. After preparation, all films were dried overnight in a drying cabinet at 80° C. and then tempered at 120° C. for 5 minutes. After tempering, the film could be easily and manually separated from the glass plate.

<b><u>comparison </u></b><b><u>Example</u></b><b><u></u></b><b><u>C5</u></b><b><u>:</u></b>

Preparation of polymer elements not according to the invention

The raw materials used were not individually degassed. In a polypropylene beaker with a speedmixer at 3000 rpm per minute over 3 minutes, 3.91 g of Desmodur N3300 (component A) has a number-average molecular weight of 6000 g/mol and an ethylene oxide unit content of 0% by weight 39.88 g of phosphorus trifunctional polypropylene glycol-polyethylene glycol-polyether (component C) and 0.12 g of DBTDL. From the still liquid reaction mixture, a film with a wet layer thickness of 1 mm was applied manually to the glass plate by means of a knife. After preparation, all films were dried overnight in a drying cabinet at 80° C. and then tempered at 120° C. for 5 minutes. After tempering, the film could be easily and manually separated from the glass plate.

<b><u>comparison </u></b><b><u>Example</u></b><b><u> C6:</u></b>

Preparation of polymer elements not according to the invention

The raw materials used were not individually degassed. In a polypropylene beaker with a speedmixer at 3000 rpm per minute over 3 minutes, 10.0 g of the prepolymer from Example 1 (component B) has a number-average molecular weight of 4000 g/mol, and the ethylene oxide unit content is 0 wt % difunctional polypropylene glycol-polyethylene glycol-polyether (component C) 39.88 g and DBTDL 0.03 g. From the still liquid reaction mixture, a film with a wet layer thickness of 1 mm was applied manually to the glass plate by means of a knife. After preparation, all films were dried overnight in a drying cabinet at 80° C. and then tempered at 120° C. for 5 minutes. It was not possible to produce test specimens from this preparation.

<b><u>according to the invention </u></b><b><u>Example</u></b><b><u></u></b><b><u>E1</u></b><b><u>:</u></b>

Preparation of the polymer element according to the invention

The raw materials used were not individually degassed. 3.0 g of Desmodur N3300 (isocyanurate as described in HDI, component A) and 7.0 g of the prepolymer from example 1 (component B) are weighed in a polypropylene beaker and with a speedmixer at 3000 rpm per minute Mix together for 1 minute. This mixture was then mixed in a polypropylene beaker with a speedmixer at 3000 rpm per minute over 3 minutes in a bifunctional polypropylene glycol having a number-average molecular weight of 4000 g/mol and an ethylene oxide unit content of 0% by weight. -polyethylene glycol-polyether (component C) 41.2 g and 0.041 g content of DBTDL. From the still liquid reaction mixture, a film with a wet layer thickness of 1 mm was applied manually to the glass plate by means of a knife. After preparation, all films were dried overnight in a drying cabinet at 80° C. and then tempered at 120° C. for 5 minutes. After tempering, the film could be easily and manually separated from the glass plate.

<b><u>according to the invention </u></b><b><u>Example</u></b><b><u></u></b><b><u>E2</u></b><b><u>:</u></b>

Preparation of the polymer element according to the invention

The raw materials used were not individually degassed. 3.0 g of Desmodur N3300 (isocyanurate as described in HDI, component A) and 7.0 g of the prepolymer from example 1 (component B) are weighed out in a polypropylene beaker and with a speedmixer at 3000 rpm per minute Mix together for 1 minute. This mixture was then mixed over 3 minutes in a polypropylene beaker with a speedmixer at 3000 rpm per minute in a trifunctional polypropylene glycol having a number-average molecular weight of 6000 g/mol and an ethylene oxide unit content of 0% by weight. -polyethylene glycol-polyether (component C) 41.2 g and 0.041 g content of DBTDL. From the still liquid reaction mixture, a film with a wet layer thickness of 1 mm was applied manually to the glass plate by means of a knife. After preparation, all films were dried overnight in a drying cabinet at 80° C. and then tempered at 120° C. for 5 minutes. After tempering, the film could be easily and manually separated from the glass plate.

<b><u>according to the invention </u></b><b><u>Example</u></b><b><u></u></b><b><u>E3</u></b><b><u>:</u></b>

Preparation of the polymer element according to the invention

The raw materials used were not individually degassed. 4.0 g of Desmodur N3300 (isocyanurate as described in HDI, component A) and 16.0 g of the prepolymer from example 1 (component B) are weighed out in a polypropylene beaker and with a speedmixer at 3000 rpm per minute Mix together for 1 minute. This mixture is then mixed over 3 minutes in a polypropylene beaker with a speedmixer at 3000 rpm per minute, a polyether having a number-average molecular weight of 4000 g/mol and an ethylene oxide unit content of 20% by weight. was mixed with DBTDL in an amount of 66.16 g and 0.132 g of difunctional polypropylene glycol-polyethylene glycol-polyether. From the still liquid reaction mixture, a film with a wet layer thickness of 1 mm was applied manually to the glass plate by means of a knife. After preparation, all films were dried overnight in a drying cabinet at 80° C. and then tempered at 120° C. for 5 minutes. After tempering, the film could be easily and manually separated from the glass plate.

<b><u>according to the invention </u></b><b><u>Example</u></b><b><u></u></b><b><u>E4</u></b><b><u>:</u></b>

Preparation of the polymer element according to the invention

The raw materials used were not individually degassed. Weigh out 1.0 g of Desmodur N3300 (isocyanurate as described in HDI, component A) and 9.0 g of the prepolymer from example 1 (component B) in a polypropylene beaker and with a speedmixer at 3000 rpm per minute Mix together for 1 minute. This mixture is then mixed over 3 minutes in a polypropylene beaker with a speedmixer at 3000 rpm per minute, a polyether having a number-average molecular weight of 4000 g/mol and an ethylene oxide unit content of 20% by weight. It was mixed with DBTDL in an amount of 24.22 g and 0.048 g of difunctional polypropylene glycol-polyethylene glycol-polyether. From the still liquid reaction mixture, a film with a wet layer thickness of 1 mm was applied manually to the glass plate by means of a knife. After preparation, all films were dried overnight in a drying cabinet at 80° C. and then tempered at 120° C. for 5 minutes. After tempering, the film could be easily and manually separated from the glass plate.

Various measurements were made on the samples. The results of the examples not according to the invention and the results of the examples of the polymer element according to the invention are shown in Table 1 below.

<tables num="1"><img file="KR20120052949A_D0001.tif" /></tables>

In this test, it was shown that the polymer element in the form of a film according to the invention offers significant advantages over the prior art. Particular disadvantages of the examples not according to the invention were the low peak elongation and high creep.

A particular advantage of using the film according to the invention is very good mechanical properties, such as high peak elongation, low modulus, low permanent elongation, low creep and high dielectric constant, at the same time very high breakthrough field strength in the unstretched state. is a combination of In particular, by using these polymer elements according to the invention, advantageous properties of the electromechanical converter produced here can be advantageously achieved.