EP2695210A1

EP2695210A1 - Use of thermoplastic polyurethanes for generating electrical energy from wave energy

Info

Publication number: EP2695210A1
Application number: EP12711387.6A
Authority: EP
Inventors: Joachim Wagner; Wolfgang BRÄUER; Dirk Schapeler
Original assignee: Bayer MaterialScience AG
Current assignee: Covestro Deutschland AG
Priority date: 2011-04-07
Filing date: 2012-03-26
Publication date: 2014-02-12
Also published as: WO2013037508A1; EP2509126A1

Abstract

The invention relates to a method for generating electrical energy from the kinetic energy of sea waves by means of a device that comprises an electroactive polymer. The invention further relates to the use of a thermoplastic polyurethane for generating electrical energy from the kinetic energy of sea waves and to a device for generating electrical energy from the kinetic energy of sea waves, said device comprising an electroactive polymer. Said electroactive polymer comprises a thermoplastic polyurethane which can be obtained by the reaction of at least: (a) one or more linear, bifunctional and hydroxy-terminated polyols with a number average molecular weight M_n of ≥ 500 g/mol to ≤ 6000 g/mol; (b) one or more diol chain extenders with a number average molecular weight M_n of ≥ 60 g/mol to ≤ 400 g/mol; and (c) one or more organic diisocyanates; the molar ratio of NCO groups in (c) to OH groups in (a) and (b) being ≥ 0.9:1 to ≤ 1.1:1.

Description

Use of thermoplastic polyurethanes for generating electrical energy

wave energy

The present invention relates to a method of recovering electrical energy from ocean wave kinetic energy, comprising the steps of providing a device, the device comprising an electroactive polymer, stretching the electroactive polymer from a minimum elongation to a maximum elongation as a result of a mechanical Influence of ocean waves and relaxation of the stretched electroactive polymer from maximum elongation to minimum elongation as a result of decreasing mechanical action by ocean waves. The invention further relates to the use of a thermoplastic polyurethane for

Obtaining electrical energy from kinetic energy of sea waves, as actuator material and / or sensor material, an actuator and / or sensor, comprising a thermoplastic polyurethane and a device for obtaining electrical energy from kinetic energy, wherein the device comprises an electroactive polymer. The energy production from water waves by means of electroactive polymer generators (EAP-

Generators) is based on the principle of converting wave energy into elongation of the EAP generator in a first stage which is then finally converted to electrical energy using an Energy Harvesting Cycle (EHC).

Examples of electromechanical converters can be found in WO 2001/06575 AI. These

Patent application relates to transducers, their use and their manufacture. Such a transducer for converting mechanical energy to electrical energy comprises at least two electrodes and a polymer. The polymer is arranged so that an electric field is changed as a result of a change in length of a first section. Furthermore, a second portion of the polymer is elastically biased. WO 2007/130252 A2 discloses systems and methods which use an EAP converter for

Use conversion of mechanical energy originally contained in one or more waves. Marine deployable devices may use a mechanical energy conversion system that transmits mechanical energy suitable for acting on the EAP converter. Such a marine device comprises a body with a portion of the body located above the water surface as the device floats in the water. The

Apparatus further comprises a system for transferring mechanical energy from a change in the level of the water surface to mechanical regulated by the system Energy. An EAP converter is coupled to a portion of the mechanical energy transfer system and configured to generate electrical energy from the regulated mechanical energy in the mechanical energy transfer system. The EAP converter has an electroactive polymer and at least two electrodes coupled to the electroactive polymer. One of the ways to improve energy production is to change the material of the electroactive polymer.

US 5,877,685 mentions a polyurethane elastomer actuator comprising a polyurethane elastomer which is deformable as a result of an electric field orientation. The

Shrinking deflection at the time of applying an electric field is transferred to another deflection. This polyurethane elastomer actuator requires no electrolyte and no high voltage. Since no chemical reactions or heat development occur, the life hardly deteriorates. The actuator described deforms to a large extent during the driving.

Thermoplastic polyurethane elastomers (TPU) have long been known. They are of industrial importance due to the combination of high quality mechanical properties with the known advantages of low cost thermoplastic processability. The use of different chemical components allows a wide range of variation

achieve mechanical properties. A review of thermoplastic polyurethane elastomers, their properties and applications is given for example in Kunststoffe 68 (1978), pages 819 to 825 or rubber, rubber, Kunststoffe 35 (1982), pages 568 to 584.

Thermoplastic polyurethane elastomers are built up from linear polyols, usually polyester or polyether polyols, organic diisocyanates and short-chain diols (chain extenders). In addition, catalysts can be added to accelerate the formation reaction. To adjust the properties of the structural components can be varied in relatively wide molar ratios. Proven molar ratios of polyols to have

Chain extenders of 1: 1 to 1: 12. This results in products with hardnesses in the range of 70 Shore A to 75 Shore D.

The thermoplastic polyurethane elastomers can be processed continuously or discontinuously. The best known technical processes are the belt process (GB 1,057,018) and the extruder process (DE 1 964 834 and 2 059 570).

The morphology suitable for improved processing behavior is only produced at high hard-segment fractions (chain extender + Diisocyanate) reached. As a result, the mobility of the soft segment (polyol + diisocyanate) is limited so that the low-temperature flexibility and the flow behavior are deteriorated. In addition, it simultaneously increases the degree of hardness of the product.

The change in morphology by increasing the molecular weight of the polyol leads to a stronger phase separation and improved mechanical properties, but by the concomitant reduction of the hard segment portion to a significant reduction in hardness (Seefried et al., J. Appl. Pol., Pp. 19, 2493, 1975 ). An improved recrystallization behavior is therefore not reported.

Previously available electroactive polyurethanes show for the application of energy conversion from sea waves to a low modulus of elasticity and too high electrical conductivity. Especially with the occurring, relatively slow wave movements, a high electrical resistance is necessary because otherwise there is unnecessary Ohmic losses. Furthermore, these materials are not recyclable.

The object of the present invention is therefore to improve an initially mentioned process for obtaining energy with regard to the polymer material used by specifying materials which are more suitable.

The object is achieved by a method for obtaining electrical energy from kinetic energy of sea waves, comprising the steps:

Providing an apparatus, the apparatus comprising an electroactive polymer interposed between electrodes and wherein in the apparatus mechanical energy is transferred from sea waves to the electroactive polymer;

Stretching the electroactive polymer from a minimum elongation to a maximum elongation as a result of a mechanical action, wherein in the stretched state of the electroactive polymer it is charged with an electrical target charge, in which the electrical breakdown field strength of the electroactive polymer is not exceeded; and Relaxing the stretched electroactive polymer from the maximum elongation to the minimum elongation due to a decreasing mechanical impact, wherein during relaxation of the electroactive polymer it is discharged to a residual charge; the process being characterized in that the electroactive polymer comprises a thermoplastic polyurethane obtainable from the reaction of at least:

(A) a linear, bifunctional and hydroxyl-terminated polyol having a number average molecular weight M _n of> 500 g / mol to <6000 g / mol; (b) a diol chain extender having a number average molecular weight M _n of> 60 g / mol to <400 g / mol; and

(c) an organic diisocyanate; wherein the molar ratio of NCO groups in (c) to OH groups in (a) and (b)> 0.9: 1 to <1, 1: 1. Electroactive polymers (EAP) in the context of the present invention are basically polymers that change their shape by the application of an electrical voltage and in particular dielectric elastomers. The electroactive polymer is disposed between electrodes, which may also be stretchable.

The proposed thermoplastic polyurethanes are characterized by a particularly favorable combination of the modulus of elasticity, the electrical resistance and the breakdown field strength. This has a favorable effect on the efficiency of energy production.

In the method according to the invention, the stretched electroactive polymer can be subjected to an electrical charge by means of a suitable unit, which can be called, for example, as power electronics or charging electronics. When relaxing or relaxing this charge is removed again, whereby electrical energy is recovered.

Linear bifunctional polyhydroxyl compounds or polyols (a) are those having an average of> 1.8 to <2.2 Zerewitinoff-active hydrogen atoms and a number average molecular weight M _n of> 500 g / mol to <6000 g / mol, preferably> 900 g / mol to <2500 g / mol. Due to production, they can contain small amounts of non-linear compounds. However, this is according to the invention locked in. Preference is given to polyether, polyester, polycarbonate diols or mixtures of these.

The number average molecular weight M _n is determined by gel permeation chromatography (GPC) in tetrahydrofuran using as calibration relationship polystyrene standards in the relevant molecular weight range.

Suitable polyether diols can be prepared by adding one or more

Alkylene oxides having 2 to 4 carbon atoms in the alkylene radical with a starter molecule containing two active hydrogen atoms bound reacted. Examples of alkylene oxides which may be mentioned are: ethylene oxide, 1,2-propylene oxide, epichlorohydrin and 1,2-butylene oxide and 2,3-butylene oxide.

Preferably used are ethylene oxide, propylene oxide and mixtures of 1,2-propylene oxide and ethylene oxide. The alkylene oxides can be used individually, alternately in succession or as mixtures. Suitable starter molecules are, for example: water, amino alcohols, such as N-alkyl-diethanolamine, for example N-methyl-diethanolamine and diols, such as ethylene glycol, 1,3-propylene glycol, 1,4-butanediol and 1,6-hexanediol. Optionally, mixtures of starter molecules can be used. Suitable polyetherols are also the hydroxyl-containing polymerization of tetrahydrofuran. It is also possible to use trifunctional polyethers in proportions of from 0 to 30% by weight, based on the bifunctional polyethers, but at most in such an amount that a still thermoplastically processable product is formed.

Suitable polyester diols may be, for example, from dicarboxylic acids having 2 to 12

Carbon atoms, preferably 4 to 6 carbon atoms, and polyhydric alcohols. Suitable dicarboxylic acids are, for example: aliphatic

Dicarboxylic acids such as succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid and sebacic acid, or aromatic dicarboxylic acids such as phthalic acid, isophthalic acid and

Terephthalic acid. The dicarboxylic acids may be used singly or as mixtures, for example in the form of an amber, glutaric and adipic acid mixture. For the preparation of the polyester diols, it may be advantageous to use, instead of the dicarboxylic acids, the corresponding dicarboxylic acid derivatives, such as carboxylic acid diesters having 1 to 4 carbon atoms in the alcohol radical, carboxylic acid anhydrides or carbonyl chlorides. Examples of polyhydric alcohols are glycols having 2 to 10, preferably 2 to 6, carbon atoms, such as ethylene glycol,

Diethylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1, 10-decanediol, 2,2-dimethyl-l, 3-propanediol, 1,3-propanediol or dipropylene glycol. Depending on the desired properties, the polyhydric alcohols may be used alone or mixed with each other. Also suitable are esters of carbonic acid with the diols mentioned, in particular those with 4 to 6 Carbon atoms, such as 1-butanediol or 1,6-hexanediol, condensation products of co-hydroxycarboxylic acids such as ω-hydroxycaproic acid or polymerization of lactones, for example optionally substituted ω-caprolactones. Ethanediol polyadipates, 1,4-butanediol polyadipates, ethanediol-1,4-butanediol polyadipates, 1,6-hexanediol neopentylglycol polyadipates, 1,6-hexanediol-1,4-butanediol polyadipates and .alpha. Are preferably used as polyester diols

Polycaprolactones.

Diol chain extenders (b) have an average of from 1.8 to 2.2 Zerewitinoff active

Hydrogen atoms and have a molecular weight M _n of> 60 g / mol to <400 g / mol.

As chain extenders are preferably aliphatic diols having 2 to 14

Carbon atoms such as ethanediol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, 1,6-hexanediol, diethylene glycol and dipropylene glycol. However, also suitable are diesters of terephthalic acid with glycols having 2 to 4 carbon atoms, for example terephthalic acid-bis-ethylene glycol or terephthalic acid bis-l, 4-butanediol, hydroxyalkylene ethers of hydroquinone, for example l, 4-di (.beta.-hydroxyethyl) - hydroquinone, ethoxylated bisphenols such as 1,4-di (.beta.-hydroxyethyl) bisphenol A. Ethanediol, 1,4-butanediol, 1,6-hexanediol, 1,4-di (.beta.-hydroxyethyl) -hydroquinone are particularly preferred as chain extenders or 1,4-di (β-hydroxyethyl) bisphenol A. It is also possible to use mixtures of the abovementioned chain extenders. In addition, smaller amounts of triols can be added

It is also possible that in addition chain extenders with amino groups,

Thiol groups or carboxyl-containing compounds can be used. For example, (cyclo) aliphatic diamines such as isophoronediamine, ethylenediamine, 1,2-propylenediamine, 1,3-propylenediamine, N-methyl-propylene-1,3-diamine, Ν, Ν'-dimethylethylenediamine and aromatic diamines, such as 2,4- Toluylenediamine, 2,6-toluenediamine, 3,5-diethyl-2,4-toluene diamine or 3,5 diethyl-2,6-toluylenediamine or primary mono-, di-, tri- or tetraalkyl-substituted 4,4'-Diaminodiphenylmethane find use.

As organic diisocyanates (c) it is possible to use aliphatic, cycloaliphatic, araliphatic, aromatic and heterocyclic diisocyanates or any desired mixtures of these diisocyanates (see HOUBEN-WEYL "Methods of Organic Chemistry", Volume E20 "Macromolecular Materials", Georg Thieme Verlag, Stuttgart, New York 1987, pp. 1587-1593 or Justus Liebigs Annalen der Chemie, 562, pages 75 to 136).

Specific examples are: aliphatic diisocyanates such as ethylene diisocyanate, 1,4-tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, 1, 12-dodecane diisocyanate; Cycloaliphatic diisocyanates such as isophorone diisocyanate, 1,4-cyclohexane diisocyanate, l-methyl-2,4-cyclohexane diisocyanate and l-methyl-2,6-cyclohexane diisocyanate and the corresponding

Isomer mixtures, 4,4'-dicyclohexylmethane diisocyanate, 2,4'-dicyclohexylmethane diisocyanate and 2,2 'dicyclohexylmethane diisocyanate and the corresponding isomer mixtures; also aromatic diisocyanates, such as 2,4-toluene diisocyanate, mixtures of 2,4-toluene diisocyanate and 2,6-toluene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate and 2,2'-diphenylmethane diisocyanate, mixtures of 2,4 ' Diphenylmethane diisocyanate and 4,4'-diphenylmethane diisocyanate, urethane-modified liquid 4,4'-diphenylmethane diisocyanates or 2,4'-diphenylmethane diisocyanates, 4,4'-diisocyanatodiphenylethane (1,2) and 1,5-naphthylene diisocyanate. Preferably used are 1,6-hexamethylene diisocyanate, isophorone diisocyanate,

Dicyclohexylmethane diisocyanate, diphenylmethane diisocyanate isomer mixtures having a 4,4'-diphenylmethane diisocyanate content of more than 96% by weight and in particular 4,4'-diphenylmethane diisocyanate and 1,5-naphthylene diisocyanate.

The diisocyanates mentioned can be used individually or in the form of mixtures with one another. They can also be used together with up to 15 mol% (calculated on the total diisocyanate) of a polyisocyanate, but at most so much polyisocyanate may be added that a still thermoplastically processable product is formed. Examples of polyisocyanates are triphenylmethane-4,4 ', 4 "-triisocyanate and polyphenyl-polymethylene-polyisocyanates Suitable catalysts are the conventional tertiary amines known from the prior art, for example triethylamine, dimethylcyclohexylamine, N-methylmorpholine, Ν, Ν'-dimethylpiperazine, 2- (dimethylamino-ethoxy) ethanol, diazabicyclo [2,2,2] octane and similar compounds and in particular organic metal compounds such as titanic acid esters,

Iron compounds or tin compounds such as tin diacetate, tin dioctoate, tin dilaurate or the tin dialkyl salts of aliphatic carboxylic acids such as dibutyltin diacetate or dibutyltin dilaurate or similar compounds. Preferred catalysts are organic metal compounds, in particular titanic acid esters, iron and tin compounds. The total amount of catalysts in the TPU according to the invention is generally about 0 to 5% by weight, preferably 0 to 2% by weight, based on the total amount of TPU. Compounds which are monofunctional with respect to isocyanates can be used in amounts of up to 2% by weight, based on TPU, as so-called chain terminators. Suitable examples are monoamines such as butyl and dibutylamine, octylamine, stearylamine, N-methylstearylamine, pyrrolidine, Piperidine or cyclohexylamine, monoalcohols such as butanol, 2-ethylhexanol, octanol, dodecanol, stearyl alcohol, the various amyl alcohols, cyclohexanol and ethylene glycol monomethyl ether.

The thermoplastic polyurethane elastomers to be used according to the invention may contain auxiliaries and additives in amounts of up to a maximum of 20% by weight, based on the total amount of TPU. Typical auxiliaries and additives are lubricants and mold release agents such as

Fatty acid esters, their metal soaps, fatty acid amides, Fettsäureesteramide and silicone compounds, antiblocking agents, inhibitors, hydrolysis stabilizers, light, heat and discoloration, dyes, pigments, inorganic and / or organic fillers, plasticizers, such as phosphates, phthalates, adipates, sebacates and Alkylsulfonsäureester, fungistatic and bacteriostatic substances and fillers and their mixtures and reinforcing agents.

Reinforcing agents are, in particular, fibrous reinforcing materials, such as, for example, inorganic fibers, which are produced according to the prior art and can also be treated with a sizing agent. Further details of the abovementioned auxiliaries and additives can be found in the specialist literature, for example the monograph by J.H. Saunders and K.C. Frisch "High Polymers", volume XVI, polyurethanes, part 1 and 2, published by Interscience Publishers 1962 and 1964, respectively

Paperback for Plastic Additives by R.Gächter u. H. Müller (Hanser Verlag Munich 1990) or DE-A 29 01 774.

For the preparation of the TPU according to the invention, the components (a), (b), (c) and

optionally further components are reacted in amounts such that the

Equivalence ratio of NCO groups of the diisocyanates (c) to the sum of the Zerewitinoff active hydrogen-containing components in (a) and (b) - 0.9: 1 to - £ 1, 1: 1. This ratio can also be> 0.95: 1 to -1.05: 1.

The structure of the thermoplastically processable polyurethane elastomers can be carried out either stepwise (prepolymer process) or by the simultaneous reaction of all components in one step (one-shot process). In the prepolymer process, an isocyanate-containing prepolymer is formed from the polyol and the diisocyanate, which is reacted in a second step with the chain extender. The thermoplastic polyurethanes according to the invention can be prepared batchwise or continuously and shaped articles can be obtained by the injection molding, extrusion or coating process. Embodiments of the method according to the invention are described below, wherein they can be combined in any way, unless clearly the opposite results from the context. In one embodiment of the process according to the invention, the polyol (a) is selected from the group comprising 1,2-polypropylene glycol polyether, 1,4-butanediol polyether and / or

Polyester polyols with 1,4-butanediol as the alcohol component. Preferred polyester polyols with 1,4-butanediol as the alcohol component contain adipic acid as the acid component. In a further embodiment of the method according to the invention, the diol

Chain extender (b) selected from the group comprising 1,4-butanediol, 1,6-hexanediol and / or bis-2-hydroxyethoxy-hydroquinone.

In a further embodiment of the method according to the invention is the organic

Polyisocyanate (c) selected from the group consisting of 4,4'-diphenylmethane diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4-diisocyanate, 1,6-hexamethylene diisocyanate and / or 1,5-naphthylene diisocyanate.

In a further embodiment of the method according to the invention, the thermoplastic polyurethane has a breakdown field strength of> 20 V / μm to <400 V / μm, an electric field

Volume resistance of> 10 ¹² ohm cm to <10 ¹⁸ ohm cm and a modulus of elasticity E 'at 50% elongation of> 2 MPa to <40 MPa. The breakdown field strength can be determined according to ASTM D 149-97a. The electrical volume resistivity can be determined according to ASTM D 257 and the modulus of elasticity E 'at 50% elongation according to DIN 53 504. Preferably, the breakdown field strength is> 60 V / μm to <300 V / μm, the volume electrical resistance> 10 ¹³ ohm cm to <10 ¹⁷ ohm cm and a Young's modulus E 'at 50% elongation of> 3 MPa to <30 MPa.

In the context of the method according to the invention, the device preferably comprises: a buoy; an axially segmented chain of fluid filled bodies of material comprising an electroactive polymer; or an assembly of floats interconnected by a hinge having eccentrically arranged biased portions of material comprising electroactive polymer which expand and relax oppositely to one another as the floats flex.

In the case of a buoy, this is followed by the buoyancy of a wave crest the rising water level and experiences an acceleration. An additional weight is attached to the buoy. On Due to the mass inertia of the additional weight, a change in the relative distance between buoy housing and additional weight will occur in this phase, as a result of which the electroactive polymer is stretched.

Likewise, during the movement of the buoy into the wave trough, a change in the relative distance between the buoy housing and additional weight occurs. For the most efficient generation of energy, at the time of maximum elongation of the polymer, it should be charged and discharged at the time of minimum elongation.

Another possibility for the case of a buoy is when the buoy is anchored to the bottom of the water body via a connection unit. Then the up and down movement of the buoy at

Swell act on a befindliches in the connection unit electroactive polymer.

The axially segmented chain of fluid filled bodies is also referred to as the "anaconda" arrangement. It has communicating fluid-filled bodies made of a material comprising an electroactive polymer. By raising the chain or hose on the wave crest, the fluid in the hose flows into the troughs. By the low

Stiffness of the electroactive polymer, the cross-section in the trough is widened (elongation) and tapered on the wave crest (relaxation).

The arrangement of floats interconnected by a hinge is also referred to as a "pelamis arrangement". It is designed so that two floats are connected to a swivel joint. Eccentrically integrated are prestressed electroactive polymers which expand and relax in opposition to each other during the kink movement of the pelamic arrangement. Rotation in the joint is achieved by placing weights in both floats in close proximity to the joint.

Another object of the present invention is the use of a thermoplastic polyurethane which is obtainable from the reaction of at least: (a) a linear, bifunctional and hydroxyl-terminated polyol having a number average molecular weight M _n of> 500 g / mol to <6000 g / mol ;

(b) a diol chain extender having a number average molecular weight M _n of> 60 g / mol to <400 g / mol; and

(c) an organic diisocyanate; wherein the molar ratio of NCO groups to OH groups is> 0.9: 1 to <1, 1: 1, as a generator material for the recovery of electrical energy from kinetic energy of

Ocean waves.

Details of the individual components have already been linked to the

inventive method explained so that reference is made to avoid repetition thereof.

The present invention also relates to an apparatus for obtaining electrical energy from momentum of ocean waves, the apparatus comprising an electroactive polymer interposed between electrodes; the apparatus being arranged to stretch the electroactive polymer as a result of a mechanical action from a minimum elongation to a maximum elongation and to relax the electroactive polymer as a result of a decreasing mechanical action from the maximum elongation to the minimum elongation; wherein the device is arranged to apply this in the stretched state of the electroactive polymer of this with an electrical target charge, in which the electrical

Breakdown field strength of the electroactive polymer is not exceeded; and wherein the apparatus is arranged to discharge it to a residual charge during relaxation of the electroactive polymer; the device comprising a buoy, an axially segmented chain of fluid filled bodies of material comprising an electroactive polymer, or an assembly of swivel bodies interconnected by a swivel having eccentrically biased portions of material comprising an electroactive polymer which deflects on the floats contrary to each other to stretch and relax, includes; and wherein the electroactive polymer comprises a thermoplastic polyurethane obtainable from the reaction of at least:

(c) an organic diisocyanate; wherein the molar ratio of NCO groups to OH groups> 0.9: 1 to <1, 1: 1. Details of the individual components have already been linked to the

In one embodiment of the device according to the invention, the polyol (a) is selected from the group comprising 1,2-polypropylene glycol polyether, 1,4-butanediol polyether and / or

Polyester polyols with 1,4-butanediol as the alcohol component.

In a further embodiment of the device according to the invention, the diol chain extender (b) is selected from the group comprising 1,4-butanediol, 1,6-hexanediol and / or bis-2-hydroxyethoxy-hydroquinone.

In a further embodiment of the device according to the invention is the organic

Polyisocyanate (c) selected from the group comprising 4,4'-diphenylmethane diisocyanate,

Isophorone diisocyanate, dicyclohexylmethane-4,4-diisocyanate, 1,6-hexamethylene diisocyanate and / or 1,5-naphthylene diisocyanate.

The present invention will be further illustrated by, but not limited to, the following examples. The examples describe the preparation of elastomers which are suitable for use in the method according to the invention for obtaining electrical energy from kinetic energy of ocean waves.

Unless otherwise indicated, all percentages are by weight and all analytical measurements are for temperatures of 23 ° C.

Measurements of film thicknesses were made with a mechanical probe from Dr. Ing. Johannes Heidenhain GmbH, Germany, Dr.-Johannes-Heidenhain-Str. 5, 83301 Traunreut. The specimens were measured at three different locations and the mean value was used as a representative measurement.

The tensile tests were carried out by means of a tractor from Zwick, model number 1455, equipped with a load cell of the total measuring range 1 kN according to DIN 53 504 with a Train speed of 50 mm / min performed. S2 specimens were used as specimens. Each measurement was carried out on three identically prepared test specimens and the mean of the data obtained was used for the evaluation. In addition to the tensile strength in

[MPa] and the elongation at break in [%] nor the stress in [MPa] at 100% and 200% elongation determined.

The determination of the permanent elongation was carried out by means of a tractor Zwicki Zwick / Roell equipped with a load cell of the total measuring range of 50 N, on a S2 rod of the sample to be examined. In this measurement, the sample with a

Speed from 50 mm / min to n * 50% stretched, after reaching this deformation, the sample is relieved to force = 0 N and the remaining strain then determined. Immediately afterwards, the next measurement cycle starts with n = n + 1; the value of n is increased until the sample breaks. Here only the value for 50% deformation is measured.

The determination of the electrical resistance was carried out by means of a laboratory setup of the company Keithley Instruments (Keithley Instruments GmbH, Landsberger Strasse 65, D-82110 Germering, Germany) Model No .: 6517 A and 8009 according to ASTM D 257, a method for determining the

Insulation resistance of materials.

The determination of the breakdown field strength according to ASTM D 149-97a was carried out with a

High Voltage Model hypotMAX made by Associated Research Inc, 13860 W Laurel Drive, Lake Forest, IL 600045-4546, USA and a self-constructed sample holder. The sample holder contacted the homogeneous-thickness polymer samples with little mechanical preload and prevented the operator from coming in contact with the stress. The non-prestressed polymer film was statically loaded in this construction with increasing voltage until an electrical breakdown took place through the film. The result of measurement was the voltage reached at breakdown, based on the thickness of the polymer film in [V / μm]. For each slide, 5 measurements were carried out and the mean value indicated.

Raw materials used:

PE 1000 1,4-butanediol polyether having a molecular weight of M _n = 1000 g / mol

PE 2000 1,4-butanediol polyether having a molecular weight of M _n = 2000 g / mol;

PES 500 1,4-butanediol adipate polyester with a molecular weight of M _n = 500 g / mol PES 1000 1, 4-butanediol adipate polyester with a molecular weight of M _n = 950 g / mol

PES 2250 1,4-butanediol adipate polyester with a molecular weight of M _n = 2250 g / mol

PP 2000 1,2-Polypropylene glycol polyether with molecular weight of M _n = 2000 g / mol MDI diphenylmethane-4,4'-diisocyanate

BUT butanediol-1,4

Hexhexanediol-1,6

HQEE bis-2-hydroxyethoxy-hydroquinone

Stabaxol 1 2,2'-6,6'-Tetraisopropyldiphenylcarbodiimide Example El

100 parts by weight of PE 1000 were heated to 150 ° C. with 0.45 parts by weight of mineral oil and 100 ppm, based on PE 1000, tin dioctoate in a reaction vessel.

While stirring (300 rpm) 55 parts by weight of MDI (60 ° C) were added. The resulting prepolymer was reacted after 1 minute with 22 parts by weight HQEE with strong mixing (1100 U / min) to the thermoplastic polyurethane (TPU). The resulting mixture was poured rapidly onto a coated panel and annealed at 120 ° C for 30 minutes. The resulting casting plates were cut and granulated

Example E2 100 parts by weight of PP 2000 were heated to 180 ° C. with 1.0 part by weight of bis-ethylene stearylamide and 20 ppm, based on PE 2000, titanyl acetylacetonate, in a reaction vessel.

While stirring (300 rpm), 51 parts by weight of MDI (60 ° C) were added. The resulting prepolymer was reacted after 1 minute with 14 parts by weight of BUT with vigorous mixing (1100 rpm) to the TPU. The resulting mixture was poured rapidly onto a coated panel and annealed at 120 ° C for 30 minutes. The resulting casting plates were cut and granulated.

Example E3

100 parts by weight of PE 2000 were heated to 180 ° C. with 0.40 part by weight of bis-ethylene stearylamide and 200 ppm, based on PE 2000, tin dioctoate in a reaction vessel. While stirring (300 rpm), 12.8 parts by weight of BUT were added. Subsequently, the

Mixture with 30 parts by weight of MDI (60 ° C.) with vigorous mixing (1100 rpm). The resulting mixture was poured rapidly onto a coated plate and annealed at 120 ° C. for 30 minutes. The resulting casting plates were cut and granulated Example E4

100 parts by weight of PE 1000 were heated to 180 ° C. in a reaction vessel containing 0.8 part by weight of bis-ethylene stearylamide, 22 parts by weight BUT and 70 ppm, based on PE 1000, tin dioctoate. With vigorous stirring (1100 rpm), 85 parts by weight of MDI (60 ° C) were added. The resulting mixture was poured rapidly onto a coated panel and annealed at 120 ° C for 30 minutes. The resulting casting plates were cut and granulated.

Example E5: (DP 9585A DPS045)

100 parts by weight of PE 1000 were in a reaction vessel with 0.15 parts by weight of bis-ethylene stearylamide, 10.4 parts by weight of BUT, 1.2 parts by weight of HEX and 250 ppm, based on PE 1000, Zinndioctoat to 180 ° C heated.

With vigorous stirring (1100 rpm), 57 parts by weight of MDI (180 ° C) were added. The resulting mixture was poured rapidly onto a coated panel and annealed at 120 ° C for 30 minutes. The resulting casting plates were cut and granulated. Example E6

100 parts by weight of PES 1000 were in a reaction vessel with 0, 1 parts by weight of bis-ethylene stearylamide, 0.6 parts by weight of Stabaxol 1, 17 parts by weight of BUT and 35 ppm, based on PES 1000, Zinndioctoat to 160 ° C heated.

With vigorous stirring (1100 rpm), 73 parts by weight of MDI were added. The resulting mixture was poured rapidly onto a coated panel and annealed at 120 ° C for 30 minutes. The resulting casting plates were cut and granulated.

Example E7

80 parts by weight PES 1000 and 20 parts by weight PES 500 were heated to 180 ° C. in a reaction vessel with 14 parts by weight BUT and 30 ppm, based on PES 1000, titanyl acetylacetonate.

With vigorous stirring (1100 rpm), 70 parts by weight of MDI (180 ° C) were added. The resulting mixture was poured rapidly onto a coated panel and annealed at 120 ° C for 30 minutes. The resulting casting plates were cut and granulated. Foil processing:

The granules were melted in a single-screw extruder 30 / 25D (Plasticorder PL 2000 6 from Brabender) (metering 3 kg / h, 170-235 ° C.) and extruded through a flat-film head into a flat film. On the samples, the electrical resistance, the

Breakdown field strength and the modulus determined in the tensile test. The results are shown in Tables 1 and 2 below.

Table 1

Table 2

It was found in the experiments that the polymer elements as films can offer significant advantages when used in the production of electrical energy, since they have very good internal resistance, high breakdown field strengths / breakdown voltages and high moduli at the operating point (for example at 50% elongation).

Furthermore, these materials have very small permanent elongations at high elongation at break, these polymer elements can advantageously be achieved particularly favorable efficiencies of the thus produced electromechanical transducer in energy production.

Claims

claims

1. A method for obtaining electrical energy from kinetic energy of

Sea waves, including the steps:

Providing a device, the device comprising an electroactive polymer which intervenes

Electrodes are arranged and wherein in the device mechanical energy is transferred from sea waves to the electroactive polymer;

Stretching the electroactive polymer from a minimum elongation to a maximum elongation as a result of a mechanical action, wherein in the stretched state of the electroactive polymer it is charged with an electrical target charge, in which the electrical breakdown field strength of the electroactive polymer is not exceeded; and

Relaxing the stretched electroactive polymer from the maximum elongation to the minimum elongation due to a decreasing mechanical impact, wherein during relaxation of the electroactive polymer it is discharged to a residual charge; The electroactive polymer comprises a thermoplastic polyurethane obtainable from the reaction of at least one of:

(A) a linear, bifunctional and hydroxyl-terminated polyol having a number average molecular weight M _n of> 500 g / mol to <6000 g / mol;

(b) a diol chain extender having a number average molecular weight M _n of> 60 g / mol to <400 g / mol; and (c) one or more organic diisocyanates; wherein the molar ratio of NCO groups in (c) to OH groups in (a) and (b)> 0.9: 1 to <1, 1: 1.

2. The method according to claim 1,

characterized in that

the polyol (a) is selected from the group comprising 1,2-polypropylene glycol polyether, 1,4-butanediol polyether and / or polyester polyols with 1,4-butanediol as the alcohol component.

3. The method according to claim 1 or 2,

characterized in that

the diol chain extender (b) is selected from the group comprising 1,4-butanediol, 1,6-hexanediol and / or bis-2-hydroxyethoxy-hydroquinone.

4. The method according to any one of claims 1 to 3,

characterized in that

the organic polyisocyanate (c) is selected from the group comprising 4,4'-diphenylmethane diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4-diisocyanate, 1,6-hexamethylene diisocyanate and / or 1,5-naphthylene diisocyanate.

5. The method according to any one of claims 1 to 4,

characterized in that

the thermoplastic polyurethane has a breakdown field strength of> 20 V / μm to <400 V / μm, a volume resistivity of> 10 ¹² ohm cm to <10 ¹⁸ ohm cm and a Young's modulus E 'at 50% elongation of> 2 MPa to <40 MPa having.

6. The method according to any one of claims 1 to 5,

characterized in that

the device: a buoy; an axially segmented chain of fluid filled bodies of material comprising an electroactive polymer; or an arrangement of floats interconnected by a hinge having eccentrically arranged biased portions of material comprising electroactive polymer that expand and relax oppositely to each other upon kinking of the floats; includes.

7. Use of a thermoplastic polyurethane obtainable from the reaction of at least:

(c) an organic diisocyanate; wherein the molar ratio of NCO groups to OH groups> 0.9: 1 to <1, 1: 1, as a generator material for obtaining electrical energy from kinetic energy of

Ocean waves.

8. Apparatus for obtaining electrical energy from kinetic energy of

Sea waves, the device comprising an electroactive polymer disposed between electrodes; the apparatus being arranged to stretch the electroactive polymer as a result of a mechanical action from a minimum elongation to a maximum elongation and to relax the electroactive polymer as a result of a decreasing mechanical action from the maximum elongation to the minimum elongation; wherein the device is arranged to apply in the stretched state of the electroactive polymer this with a target electrical charge, in which the electrical breakdown field strength of the electroactive polymer is not exceeded; and wherein the apparatus is arranged to discharge it to a residual charge during relaxation of the electroactive polymer; d a d u r c h e s e n c i n e s, d a s s

the device comprises a buoy, an axially segmented chain of fluid filled bodies of material comprising an electroactive polymer, or an array of floats interconnected by a pivot having eccentrically biased portions of material comprising electroactive polymer which is opposite to an articulation of the floats stretch and relax each other; and the electroactive polymer comprises a thermoplastic polyurethane obtainable from the reaction of at least:

(c) an organic diisocyanate; wherein the molar ratio of NCO groups to OH groups is> 0.9: 1 to <1.1: 1.

9. Apparatus according to claim 8,

characterized in that

10. Apparatus according to claim 8 or 9,

characterized in that

11. Device according to one of claims 8 to 10,

characterized in that