EP2695209A1

EP2695209A1 - Use of thermoplastic polyurethanes for converting mechanical energy to electrical energy

Info

Publication number: EP2695209A1
Application number: EP12710290.3A
Authority: EP
Inventors: Joachim Wagner; Wolfgang BRÄUER; Dirk Schapeler
Original assignee: Bayer Intellectual Property GmbH
Current assignee: Bayer Intellectual Property GmbH
Priority date: 2011-04-07
Filing date: 2012-03-26
Publication date: 2014-02-12
Also published as: EP2509127A1; WO2012136503A1

Abstract

The invention relates to a method for generating electrical energy from kinetic energy using a device that comprises an electroactive polymer. The invention further relates to the use of a thermoplastic polyurethane for generating electrical energy from kinetic energy as an actuator material and/or sensor material, to an actuator and/or sensor comprising a thermoplastic polyurethane, and to a device for generating electrical energy from kinetic energy, wherein the device comprises an electroactive polymer. The electroactive polymer comprises a thermoplastic polyurethane, which can be obtained by reacting at least: (a) one or more linear, bifunctional and hydroxyl-terminated polyols having a number average molecular weight M_n of ≥ 500 g/mol to ≤ 6000 g/mol; (b) one or more diol chain extenders having a number average molecular weight M_n of ≥ 60 g/mol to ≤ 400 g/mol; and (c) one or more organic diisocyanates, where the molar ratio between NCO groups in (c) and OH groups in (a) and (b) is ≥ 0.9:1 to ≤ 1.1:1.

Description

Use of thermoplastic polyurethanes for the conversion of mechanical energy into electrical energy

The present invention relates to a method for obtaining electrical energy from kinetic energy, comprising the steps of providing a device, wherein the

Apparatus comprising an electroactive polymer, stretching the electroactive polymer from a minimum elongation to a maximum elongation as a result of mechanical action, and relaxing the stretched electroactive polymer from the maximum elongation to the minimum elongation due to a decreasing mechanical impact. The present invention does not relate to the recovery of electrical energy from the momentum of ocean waves.

The invention further relates to the use of a thermoplastic polyurethane for

Obtaining electrical energy from kinetic energy, as an 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 recovery from kinetic energy by means of electroactive polymer generators (EAP generators) is based on the principle of the conversion of mechanical energy into an elongation of the EAP generator in a first stage, which then using a

Energy Harvesting Cycle (EHC) is finally converted into electrical energy.

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.

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.

JP 3026043 relates to a polyurethane elastomer actuator based on a dielectric polyol. This polyol is oriented in the field direction when an electric field is applied.

JP 07-240544 relates to a polyurethane elastomer actuator based on a polycarbonate polyol. This polyol is oriented in the field direction when an electric field is applied.

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. Molar ratios of polyols to chain extenders of 1: 1 to 1: 12 have proven useful. This results in products with hardnesses in the range from 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 extmder process (DE 1 964 834 and 2 059 570). The morphology which is suitable for improved processing behavior is only achieved in the case of products which are prepared by customary processes at high hard-segment proportions (chain extender + diisocyanate). 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 values, but by the simultaneous Reduction of the hard segment portion to a significant reduction in hardness (Seefried et al., J. Appl. Pol., Sci., 19, 2493, 1975). An improved recrystallization behavior is therefore not reported.

The object of the present invention has been made to improve an initially mentioned method for obtaining energy in terms of the polymer material used by specifying more suitable materials.

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

Providing a device, the device comprising an electroactive polymer disposed between electrodes and wherein mechanical energy is transferred to the electroactive polymer in the device;

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 included according to the invention. 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 be used. 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, suitable are also 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 (β-hydroxyethyl) hydroquinone or 1,4-di (β-hydroxyethyl) bisphenol A are particularly preferably used as chain extenders. 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 tertiary amines known and customary in the prior art, for example triethylamine, dimethylcyclohexylamine, N-methylmorpholine, Ν, Ν'-dimethylpiperazine, 2- (dimethylaminoethoxy) 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 are in the specialist literature, for example the monograph by JH Saunders and KC Frisch "High Polymers", Volume XVI, polyurethanes, part 1 and 2, published by Interscience Publishers 1962 and 1964, the paperback for plastic additives 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 process 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-hydroxyethoxyhydroquinone.

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 ohm cm to <10 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 a further embodiment of the method according to the invention, the kinetic energy is the kinetic energy of air flows or of water flows.

Another object of the present invention is the use of 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;

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

In particular, the above-mentioned thermoplastic polyurethane can be used to recover electric energy from motive energy of air currents or flows of water. The application of this method to the extraction of electrical energy from the

Motion energy from sea waves is not the subject of this invention.

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 a device for obtaining electrical energy from kinetic energy, in particular from air currents or water flows, the device comprising an electroactive polymer which is arranged 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 be in the stretched state of the electroactive

Polymers this apply to 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; wherein 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 to OH groups> 0.9: 1 to <1, 1: 1.

The device according to the invention is not used for obtaining electrical energy from the kinetic energy of sea waves. Details of the individual components have already been explained in connection with the method according to the invention, so that reference is made to avoid repetition.

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.

Another object of the present invention is an actuator and / or sensor comprising a thermoplastic polyurethane obtainable from the reaction of at least:

Again, reference is generally made to avoid repetition on the corresponding statements to the inventive method.

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 process according to the invention.

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 pulling speed of 50 mm / min. 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 Source model hypotMAX from Associated Research Inc, 13860 W Laurel

Drive, Lake Forest, IL 600045-4546, USA and a self-constructed sample holder.

The sample holder contacted the homogeneously thick polymer samples with only little mechanical

Preload and prevented the operator from coming into contact with the tension. 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]. There were ever slide 5

Measurements carried out and the mean 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 having molecular weight 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 after 1 minute with 14 parts by weight 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 was reacted 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 in a reaction vessel were charged 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 heated to PE 1000, Zinndioctoat to 180 ° C.

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, have 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

A method of recovering electrical energy from kinetic energy, comprising the steps of:

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

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

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:

(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 kinetic energy is the kinetic energy of air currents.

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

characterized in that

the kinetic energy is the kinetic energy of water currents

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

(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> 0.9: 1 to <1, 1: 1, for the recovery of electrical energy from kinetic energy, as Aktuatormaterial and / or as a sensor material.

9. A device for obtaining electrical energy from kinetic energy, in particular from air currents or water flows, the device comprising an electroactive polymer which is arranged 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; The electroactive polymer comprises a thermoplastic polyurethane obtainable from the reaction of at least one of:

10. Apparatus according to claim 9,

characterized in that

11. Apparatus according to claim 9 or 10,

characterized in that

12. Device according to one of claims 9 to 11,

characterized in that

An actuator and / or sensor comprising a thermoplastic polyurethane obtainable from the reaction of at least:

(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.