阅读说明：本技术 包含导电丙烯酸酯基压敏粘合剂的电极 (Electrode comprising a conductive acrylate-based pressure sensitive adhesive ) 是由 C·内格勒 I·范德默伦 S·吉利森 T·罗舍克 F·格特尔 A·贝斯莱尔 于 2020-03-02 设计创作，主要内容包括：本发明涉及包括导电压敏粘合剂层和导电层的电极。此外,本发明涉及制造电极的方法和该电极用于监测生物信号的用途。(The present invention relates to an electrode comprising a conductive pressure sensitive adhesive layer and a conductive layer. Furthermore, the invention relates to a method of manufacturing an electrode and the use of the electrode for monitoring a biological signal.)

1. An electrode comprising or consisting of:

(A) an electrically conductive pressure sensitive adhesive layer comprising or consisting of

(A1) At least one (meth) acrylic polymer obtained by polymerizing (meth) acrylic monomers, optionally with vinyl monomers, wherein at least 10% by weight of the (meth) acrylic monomers comprise at least one-OH group, wherein weight percent is based on the total weight of the acrylic polymer;

(A2) at least one ionic liquid;

(A3) optionally at least one ion conductivity promoter;

(A4) optionally at least one conductive particle;

(A5) optionally at least one polyol; and

(A6) optionally at least one solvent;

(B) a conductive layer in contact with the conductive pressure sensitive adhesive layer;

(C) an optional substrate in contact with the conductive layer; and

(D) an optional release liner in contact with the electrically conductive pressure sensitive adhesive layer.

2. The electrode of claim 1, wherein the electrically conductive pressure sensitive adhesive layer (a) comprises or consists of:

(i) the (meth) acrylic monomer containing at least one-OH group is present in at least 15 wt%, preferably at least 20 wt%, more preferably at least 25 wt%, most preferably at least 30 wt% and/or at most 65 wt%, preferably at most 60 wt%, more preferably at most 55 wt%, most preferably at most 50 wt%, based on the total weight of the acrylic polymer; and is

(ii) The (meth) acrylic monomer is selected from the group consisting of methyl (meth) acrylate, hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, butyl acrylate, ethylhexyl acrylate, acrylic acid, C2-C18 alkyl (meth) acrylate, acrylamide, cyclohexyl (meth) acrylate, glycidyl (meth) acrylate, and benzyl (meth) acrylate; and/or

(iii) The vinyl monomer is selected from vinyl acetate, N-vinyl caprolactam, acrylonitrile and vinyl ether; and/or

(iv) The (meth) acrylic monomer is a mixture of at least one selected from methyl (meth) acrylate, butyl acrylate and ethylhexyl acrylate and hydroxyethyl acrylate, or a mixture of at least one selected from methyl (meth) acrylate, butyl acrylate and ethylhexyl acrylate and hydroxyethyl acrylate; and/or

(v) The at least one polyol is selected from polyether polyols, preferably from polyethylene glycol, polypropylene glycol, polytetramethylene glycol or mixtures thereof, more preferably polyethylene glycol having a weight average molecular weight of 300 to 1000g/mol or 350 to 750g/mol or 380 to 420g/mol, wherein the molecular weight is measured by gel permeation chromatography according to DIN 55672-1:2007-08 with THF as eluent; and/or

(vi) The polyol is present at 0.1 to 50 weight percent or 0.5 to 20 weight percent based on the total weight of the electrically conductive pressure sensitive adhesive layer; and/or

(vii) The solvent is selected from the group consisting of water, ethyl acetate, butyl diglycol, 2-butoxyethanol, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, methanol, isopropanol, butanol, dibasic esters, hexane, heptane, 2, 4-pentanedione, toluene, xylene, benzene, hexane, heptane, methyl ethyl ketone, methyl isobutyl ketone, diethyl ether and mixtures thereof, preferably the solvent is selected from the group consisting of ethyl acetate, butyl acetate, ethylene glycol, propylene glycol and mixtures thereof; and/or

(viii) The solvent is present in 0.001 to 10 wt%, preferably 0.001 to 5 wt%, more preferably 0.01 to 1 wt%, based on the total weight of the conductive pressure sensitive adhesive layer (a); and/or

(ix) The acrylic polymer (a1) is present at 10 to 99 weight percent, or 15 to 97 weight percent, or 50 to 95 weight percent, based on the total weight of the electrically conductive pressure sensitive adhesive layer (a); and/or

(x) The ionic liquid (A2) is selected from the group consisting of imidazolium acetate, imidazolium sulfonate, imidazolium chloride, imidazolium sulfate, imidazolium phosphate, imidazolium thiocyanate, imidazolium dicyanamide, imidazolium benzoate, imidazolium trifluoromethanesulfonate, choline saccharinate, choline sulfamate, pyridinium acetate, pyridinium sulfonate, pyridinium chloride, pyridinium sulfate, pyridinium phosphate, pyridinium thiocyanate, pyridinium dicyanamide, pyridinium benzoate, pyridinium trifluoromethanesulfonate, pyrrolidinium acetate, pyrrolidinium sulfonate, pyrrolidinium chloride, pyrrolidinium sulfate, pyrrolidinium phosphate, pyrrolidinium thiocyanate, pyrrolidinium dicyanamide, pyrrolidinium benzoate, pyrrolidinium trifluoromethanesulfonate, pyrrolidinium acetate, pyrrolidinium thiocyanate, pyrrolidinium dicyanamide, pyrrolidinium benzoate, pyrrolidinium trifluoromethanesulfonate, pyrrolidinium chloride, pyrrolidinium sulfate, Phosphonium sulfonate, phosphonium chloride, phosphonium sulfate, phosphonium phosphate, phosphonium thiocyanate, phosphonium dicyanamide salt, phosphonium benzoate, phosphonium trifluoromethanesulfonate, sulfonium acetate, sulfonium sulfonate, sulfonium chloride, sulfonium sulfate, sulfonium phosphate, sulfonium thiocyanate, sulfonium dicyanamide salt, sulfonium benzoate, sulfonium trifluoromethanesulfonate, ammonium acetate, ammonium sulfonate, ammonium chloride, ammonium sulfate, ammonium phosphate, ammonium thiocyanate, ammonium dicyanamide salt, ammonium benzoate, ammonium trifluoromethanesulfonate, and mixtures thereof; and/or

(xi) The ionic liquid is selected from the group consisting of 1-ethyl-3-methylimidazolium acetate, 1-ethyl-3-methylimidazolium methanesulfonate, 1-ethyl-3-methylimidazolium trifluoromethanesulfonate, 1-ethyl-3-methylimidazolium chloride, 1-ethyl-3-methylimidazolium ethylsulfate, 1-ethyl-3-methylimidazolium diethylphosphate, 1-ethyl-3-methylimidazolium thiocyanate, 1-ethyl-3-methylimidazolium dicyanamide salt, 1-ethyl-3-methylimidazolium benzoate, choline trifluoromethanesulfonate, choline saccharinate, choline acetaminosulfonate, choline N-cyclohexylsulfamate, tris (2-hydroxyethyl) methylammonium methylsulfate, 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-allyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide, 1-ethyl-3-methylimidazolium ethylsulfate, choline acetate and mixtures thereof, preferably selected from the group consisting of 1-ethyl-3-methylimidazolium benzoate, 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-ethyl-3-methylimidazolium methanesulfonate, 1-ethyl-3-methylimidazolium chloride, 1-ethyl-3-methylimidazolium trifluoromethanesulfonate, choline trifluoromethanesulfonate, 1-ethyl-3-methylimidazolium acetate, choline acetate, 1-ethyl-3-methylimidazolium diethylphosphate, 1-allyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide, 1-ethyl-3-methylimidazolium ethylsulfate, 1-ethyl-3-methylimidazolium thiocyanate, 1-ethyl-3-methylimidazolium dicyanamide, choline saccharinate, choline acetamidosulfonate, 1-ethyl-3-methylimidazolium ethyl sulfate and mixtures thereof; and/or

(xii) The ionic liquid is present at 0.5 to 50 wt%, or 1 to 40 wt%, or 4 to 25 wt%, based on the total weight of the electrically conductive pressure sensitive adhesive layer; and/or

(xiii) The ionic conductivity promoter is selected from the group consisting of choline chloride, choline bitartrate, choline dihydrogen citrate, choline phosphate, choline gluconate, choline fumarate, choline carbonate, choline pyrophosphate, and mixtures thereof; and/or

(xiv) The ionic conductivity promoter is present at 0.1 to 30 wt.%, or 0.5 to 20 wt.%, or 1 to 15 wt.%, based on the total weight of the electrically conductive pressure sensitive adhesive layer; and/or

(xv) The electrically conductive particles are selected from the group consisting of metal (nano) particles, graphite (nano) particles, carbon nanowires, electrically conductive polymer (nano) particles and mixtures thereof, more preferably from the group consisting of silver-containing particles, silver particles, copper-containing particles, silver nanowires, copper nanowires, graphite particles, carbon particles and mixtures thereof, and even more preferably from the group consisting of graphite particles, carbon particles and mixtures thereof.

3. The electrode of claim 1 or 2, wherein the electrically conductive pressure sensitive adhesive layer

(i) Has a thickness of 1 to 200 μm, or 10 to 50 μm; and/or

(ii) Having a frequency of 10 at 10Hz¹To 10⁷Omega, or 10²To 10⁵Impedance value of Ω.

4. Electrode according to one of the preceding claims, wherein the conductive layer

(i) Selected from a metal or metal salt layer, in particular copper, silver, gold, aluminium, Ag/AgCl, or a carbon layer or a mixture thereof; and/or

(ii) Has a thickness of 0.1 to 500 μm, or 0.5 to 150 μm, or 1 to 25 μm, or 1 to 20 μm; and/or

(iii) Is the only conductive layer contained in the electrode other than the conductive pressure sensitive adhesive.

5. Electrode according to one of the preceding claims, wherein the substrate

(i) Is a flexible film, preferably selected from polyolefin films, polycarbonate films, thermoplastic polyurethane films, silicone films, woven films, non-woven films or paper films, in particular polyethylene films, polypropylene films, polyethylene terephthalate films or thermoplastic polyurethane films; and/or

(ii) Has a thickness of 10 to 500 μm, or 25 to 150 μm.

6. The electrode according to any one of the preceding claims, wherein the release liner is selected from siliconized paper or plastic release liner.

7. Electrode according to one of the preceding claims, wherein the electrode

(i) Substantially free of hydrogel, preferably containing no more than 0.5 wt.%, or 0.1 wt.%, or 0.001 wt.% of hydrogel, or no hydrogel, based on the total weight of the electrode; and/or

(ii) Substantially free of an aqueous electrolyte paste, preferably containing no more than 0.5 wt.%, or 0.1 wt.%, or 0.001 wt.%, based on the total weight of the electrode, of an aqueous electrolyte paste, or containing no aqueous electrolyte paste; and/or

(iii) Substantially free of water, preferably containing no more than 2 wt.%, or 0.5 wt.%, or 0.01 wt.% water, based on the total weight of the electrode, or free of water.

8. Method of manufacturing an electrode according to one of claims 1 to 7, comprising or consisting of the steps of:

(i) optionally providing a substrate on one side of which a conductive layer is applied by flat screen printing, rotary screen printing, flexography, gravure, pad printing, inkjet printing, LIFT printing, vacuum based deposition methods such as CVC, PVD and ALD, spraying, dipping or immersion plating;

(ii) applying the electrically conductive pressure sensitive adhesive layer on the electrically conductive layer by coating, laminating, spraying or printing; and

(iii) a release liner is optionally applied over the conductive pressure sensitive adhesive layer on that side.

9. The method of claim 8, wherein in step (ii), the electrically conductive pressure sensitive adhesive layer partially or completely covers a surface of the electrically conductive layer.

10. The method according to claim 8 or 9, wherein after applying the electrically conductive pressure sensitive adhesive layer, the layer is cured preferably at 20 to 150 ℃, more preferably at 80 to 130 ℃, for 1 second to 2 hours, preferably 3 seconds to 15 minutes.

11. The process according to one of claims 8 to 10, wherein after applying the conductive layer, the conductive layer is dried preferably at 20 to 200 ℃, more preferably at 30 to 150 ℃ for 1 second to 2 hours, preferably 3 seconds to 10 minutes.

12. Use of an electrode according to one of claims 1 to 7 for monitoring a bio signal, preferably an ECG, an EEG, an EMG or a bioimpedance.

Technical Field

The present invention relates to an electrode comprising a conductive pressure sensitive adhesive layer and a conductive layer. Furthermore, the invention relates to a method of manufacturing the electrode and to the use of the electrode for monitoring a biological signal.

Background

Various electrodes are used to measure biological signals such as Electrocardiogram (ECG), electroencephalogram (EEG), and Electromyogram (EMG).

For example, ECG electrodes currently in use are attached to the skin by a gel that acts as an electrolyte and transmits body signals to the electrodes. However, they dry out over time and cannot be used for long time measurements. In most cases, use over 24 hours is not recommended. Furthermore, they can only be stored for a relatively short time, usually only one month after sealing, and they require special packaging to prevent them from drying out.

In particular, currently used gel electrodes have a high salt concentration, which is necessary for low impedance and good signal quality. However, in many cases, high salt concentrations cause skin irritation. Moreover, these electrodes require relatively large amounts of water. High water content is one reason that these electrodes tend to dry out and therefore cannot be used for long term measurements (especially over three days) because the signal quality decreases with decreasing water content. Current gel electrodes are attached to the skin using a ring of pressure sensitive skin adhesive surrounding the inner gel.

There are also tab electrodes on the market today that are attached to the skin by gel type adhesives. These electrodes do not require additional skin adhesive as the gel itself adheres to the skin. However, these electrodes also contain salt and water and dry out over time and are therefore unsuitable for long-time measurements. The adhesion of the binder in these electrodes is often poor, resulting in adhesive failure when the electrode is removed.

Alternatively, a pressure sensitive adhesive containing a conductive filler (such as carbon black) can be used in the electrode to measure the biological signal. A disadvantage of this electrode is that a high concentration of carbon black is required, which leads to a loss of adhesion. In addition, the signal quality in such electrodes is poor due to the lack of ionic conductivity.

In another electrode solution, the electrode comprises a binder comprising a combination of carbon black and a salt. In order to obtain sufficient impedance in the solution, the conductive fillers need to be electrophoretically aligned. However, this electrophoretic activation step makes the electrode production expensive and complicated.

Therefore, there is a need for an electrode for measuring bio-signals that can be used for one week without losing signal or adhesion, without drying out, and without sensitizing or irritating the skin.

Disclosure of Invention

The inventors of the present invention have surprisingly found that one or more of the above disadvantages can be overcome by a specific electrode of the present invention comprising an electrically conductive pressure sensitive adhesive layer, hereinafter also referred to as adhesive layer, comprising at least one acrylic polymer, obtained by polymerizing (meth) acrylic monomers, optionally with vinyl monomers, wherein at least 10 wt% of the (meth) acrylic monomers comprise at least one-OH group, wherein the weight percentages are based on the total weight of the acrylic polymer and the at least one ionic liquid. The electrode of the present invention not only does not dry out and can be used for long-term measurement without irritating the skin, but also can be more easily manufactured. Since no additional hydrogel is required, the electrodes can be printed in a rather simple way at one manufacturer. Due to the fact that the present electrode does not require a gel/hydrogel, the shelf life of the electrode is improved and less demanding packaging materials are required.

Drawings

Fig. 1a-f (cross-section) illustrate a preferred embodiment of an electrode according to the present invention. The following layers were used: a conductive pressure sensitive adhesive layer (10), a conductive layer (20) made of carbon, a flexible substrate (30), a conductive layer (40) made of Ag/AgCl, a metal layer (50), a conductive layer (60) made of Ag, a release liner (70), a conductive element (80) made of a flexible substrate (30) covered with at least one conductive layer ((20), (40) or (60)) in contact with the pressure sensitive adhesive layer (10).

Fig. 2a-e (top view) illustrate a preferred embodiment of the pattern of the conductive pressure sensitive adhesive layer (10) on the conductive element (80).

FIG. 3 illustrates the impedance spectra recorded from examples 1a-d and comparative example 1.

Fig. 4 illustrates ECG spectra recorded from example 1c and comparative example 1.

FIG. 5 illustrates impedance spectra on Ag/AgCl electrodes of compositions according to examples 1 (solid line) and 2 (dashed line).

Fig. 6 illustrates the defibrillation overload recovery test curves of examples 2-4.

Fig. 7 illustrates a defibrillation overload recovery discharge curve according to ANSI/AAMI EC12:2000/(R)2015 for an electrode pair having an electrode adhesive according to example 2.

Fig. 8 illustrates a defibrillation overload recovery discharge curve according to ANSI/AAMI EC12:2000/(R)2015 for an electrode pair having an electrode adhesive according to example 1.

Fig. 9 illustrates the voltage increase during current biasing for electrode samples (examples 1 and 2) with different binder compositions.

Fig. 10 illustrates the voltage increase during long-time current biasing (200nA) of the electrode sample with electrode binder (example 1).

Fig. 11 illustrates the voltage increase during long time current bias (2 μ a) for the electrode sample with electrode binder (example 1).

FIG. 12 illustrates the offset instability and internal noise measurements of an electrode sample (example 1) having an electrode binder according to the present invention.

Detailed Description

In a first aspect, the invention relates to an electrode comprising or consisting of: (A) an electrically conductive pressure sensitive adhesive layer comprising or consisting of

(A1) At least one (meth) acrylic polymer obtained by polymerizing (meth) acrylic monomers, optionally with vinyl monomers, wherein at least 10% by weight of the (meth) acrylic monomers comprise at least one-OH group, wherein the weight percentages are based on the total weight of the acrylic polymer;

(A2) at least one ionic liquid;

(A3) optionally at least one ion conductivity promoter;

(A4) optionally at least one conductive particle;

(A5) optionally at least one polyol; and

(A6) optionally at least one solvent;

(B) a conductive layer in contact with the conductive pressure sensitive adhesive layer;

(C) an optional substrate in contact with the conductive layer; and

(D) an optional release liner in contact with the electrically conductive pressure sensitive adhesive layer.

In a second aspect, the invention relates to a method of manufacturing an electrode according to the invention, the method comprising or consisting of the steps of:

(i) optionally providing a substrate on one side of which a conductive layer is applied by flat screen printing, rotary screen printing, flexography, gravure, pad printing, inkjet printing, LIFT printing, vacuum based deposition methods such as CVC, PVD and ALD, spraying, dipping or immersion plating;

(ii) applying a conductive pressure sensitive adhesive layer on the conductive layer by coating, laminating, spraying, or printing; and

(iii) a release liner is optionally applied over the side conductive voltage sensitive adhesive layer.

In a final aspect, the invention relates to the use of an electrode according to the invention for monitoring a bio-signal, preferably an ECG, EEG, EMG or bioimpedance.

In the following paragraphs, the present invention will be described in more detail. Each described embodiment may be combined with any other aspect or embodiment unless clearly indicated to the contrary. In particular, any feature indicated as being preferred or advantageous may be combined with any other feature or features indicated as being preferred or advantageous.

In the context of the present invention, the terms used will be construed according to the following definitions, unless the context indicates otherwise.

The term "substantially free" means, if not explicitly stated otherwise, a compound or substance at a concentration of less than 0.1 wt.%, preferably less than 0.01 wt.%, more preferably less than 0.001 wt.%, more preferably less than 0.0001 wt.%, in particular free of the compound or substance.

As used herein, the terms "comprising," "comprises," and "consisting of … … (of)" are synonymous with "including," "includes," or "containing," "containing," and are inclusive or open-ended and do not exclude other non-recited members, elements, or method steps.

The recitation of numerical endpoints includes all numbers and fractions within the respective range, as well as the recited endpoint.

All percentages, parts, ratios, etc. mentioned herein are by weight unless otherwise indicated.

When an amount, concentration, or other value or parameter is expressed as a range, preferred upper limit, preferred lower limit, it is to be understood that any range obtained by combining any upper limit or preferred value with any lower limit is also specifically disclosed, regardless of whether the obtained range is explicitly mentioned in the context.

All references cited in this specification are incorporated herein by reference in their entirety.

Unless defined otherwise, all terms used in disclosing the invention, including technical and scientific terms, have the meaning commonly understood by one of ordinary skill in the art to which this invention belongs. By way of further guidance, definitions of terms are included to better understand the teachings of the present invention.

The invention relates to electrodes that do not require a gel or hydrogel, and therefore the term "dry electrode" is also used for electrodes according to the invention.

The electrode comprises a conductive pressure sensitive adhesive layer comprising or consisting of (a1) at least one acrylic polymer obtained by polymerizing (meth) acrylic monomers optionally with vinyl monomers, wherein at least 10 wt% of the (meth) acrylic monomers comprise at least one-OH group, wherein the weight percentages are based on the total weight of the acrylic polymer and the at least one ionic liquid.

Adhesives suitable for use in the present invention are electrically conductive Pressure Sensitive Adhesives (PSAs), particularly ion conductive adhesives, having low resistance and good skin compatibility. The adhesive is present in the electrode in the form of a layer, providing a solution for long term monitoring of bio-signals by acting as a functional contact between the electrode and the skin. It does not dry out and cause skin irritation, compared to gel type electrodes currently on the market. Furthermore, the impedance of the PSA according to the invention is very low without any addition of water.

The electrically conductive pressure sensitive adhesive according to the present invention is based on a polar solvent based acrylic pressure sensitive adhesive with high gas permeability and a non-toxic, non-irritating ionic liquid resulting in ionic conductivity.

In one embodiment, in the adhesive layer, the (meth) acrylic monomer containing at least one-OH group is present at least 15 wt%, preferably at least 20 wt%, more preferably at least 25 wt%, most preferably at least 30 wt% and/or at most 65 wt%, preferably at most 60 wt%, more preferably at most 55 wt%, most preferably at most 50 wt%, based on the total weight of the acrylic polymer. When the content of the (meth) acrylic monomer including at least one-OH group in the (meth) acrylic polymer is more than 65% by weight based on the total weight of the (meth) acrylate polymer, a higher OH-group content may negatively affect the adhesive properties.

In another embodiment, in the adhesive layer, the (meth) acrylic monomer is selected from the group consisting of methyl (meth) acrylate, hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, butyl acrylate, ethylhexyl acrylate, acrylic acid, C2-C18 alkyl (meth) acrylates, (meth) acrylamide, cyclohexyl (meth) acrylate, glycidyl (meth) acrylate, and benzyl (meth) acrylate.

In another embodiment, in the adhesive layer, the vinyl monomer is selected from the group consisting of vinyl acetate, N-vinyl caprolactam, acrylonitrile, and vinyl ether.

In another embodiment, in the adhesive layer, the (meth) acrylic monomer is a mixture of at least one selected from the group consisting of methyl (meth) acrylate, butyl acrylate, and ethylhexyl acrylate with hydroxyethyl acrylate, or a mixture of at least one selected from the group consisting of methyl (meth) acrylate, butyl acrylate, and ethylhexyl acrylate with hydroxyethyl acrylate.

Suitable commercially available (meth) acrylic polymers for use in the present invention include, but are not limited to, LOCTITE DURO-TAK 222A, LOCTITE DURO-TAK 87-202A, LOCTITE DURO-TAK 87-402A, LOCTITE DURO-TAK 73-626A from Henkel.

Applicants have found that pressure sensitive adhesives based on at least one acrylic polymer obtained by polymerizing (meth) acrylic monomers, optionally with vinyl monomers, wherein at least 10 wt% of the (meth) acrylic monomers comprise at least one-OH group, wherein the weight percentages are based on the total weight of the acrylic polymer, provide good resistance and the electrodes do not dry out, and that they can be used for longer time measurements (higher OH content increases the water vapor transmission rate of the polymer, which contributes to increased gas permeability and longer wear time).

In one embodiment, in the adhesive layer, the polyol is selected from polyether polyols, preferably from polyethylene glycol, polypropylene glycol, polytetramethylene glycol, more preferably from polyethylene glycol having a weight average molecular weight of 300 to 1000g/mol or 350 to 750g/mol or 380 to 420g/mol, wherein the molecular weight is measured by gel permeation chromatography according to DIN 55672-1:2007-08 with THF as eluent. The adhesive layer according to the present invention may further comprise a polyether polyol. Preferably, the polyether polyol is selected from the group consisting of polyethylene glycol (PEG), polypropylene glycol (PPG), polytetramethylene glycol (PTMG) and mixtures thereof. The applicant has found that the addition of polyether polyols is a very good host for ion conductivity due to the open and flexible molecular chains and therefore has a positive effect on the impedance. Applicants have found that small amounts of polyether polyols have a positive effect, which is beneficial for the skin compatibility of the composition. Suitable commercially available polyether polyols for use in the present invention include, but are not limited to, Kollisolv PEG 400 from BASF.

In another embodiment, in the adhesive layer, the polyol is present at 0.1 to 50 weight percent or 0.5 to 20 weight percent based on the total weight of the adhesive layer.

In another embodiment, in the adhesive layer, the solvent is selected from the group consisting of water, ethyl acetate, butyl diglycol, 2-butoxyethanol, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, methanol, isopropanol, butanol, dibasic esters, hexane, heptane, 2, 4-pentanedione, toluene, xylene, benzene, hexane, heptane, methyl ethyl ketone, methyl isobutyl ketone, diethyl ether, and mixtures thereof, preferably the solvent is selected from the group consisting of ethyl acetate, butyl acetate, ethylene glycol, propylene glycol, and mixtures thereof.

In another embodiment, in the adhesive layer, the solvent is present in 0.001 to 10 wt%, preferably 0.001 to 5 wt%, more preferably 0.01 to 1 wt%, based on the total weight of the conductive pressure sensitive adhesive layer (a).

Most preferably, the adhesive layer is substantially free of solvent, preferably as defined above.

In one embodiment, in the adhesive layer, (meth) acrylic polymer (a1) is present at 10 to 99 weight percent, or 15 to 97 weight percent, or 50 to 95 weight percent, based on the total weight of the conductive pressure sensitive adhesive layer (a). Less than 10 wt% of the (meth) acrylate polymer may result in poor adhesion properties and is detrimental to film forming properties.

The adhesive layer according to the invention comprises an ionic liquid, preferably a non-toxic, non-irritating ionic liquid which results in ionic conductivity.

In another embodiment, in the adhesive layer, the ionic liquid (a2) is selected from imidazolium acetate, imidazolium sulfonate, imidazolium chloride, imidazolium sulfate, imidazolium phosphate, imidazolium thiocyanate, imidazolium dicyanamide salt, imidazolium benzoate, imidazolium trifluoromethanesulfonate, choline saccharinate, choline sulfamate, pyridinium acetate, pyridinium sulfonate, pyridinium chloride, pyridinium sulfate, pyridinium phosphate, pyridinium thiocyanate, pyridinium dicyanamide salt, pyridinium benzoate, pyridinium trifluoromethanesulfonate, pyrrolidinium acetate, pyrrolidinium sulfonate, pyrrolidinium chloride, pyrrolidinium sulfate, pyrrolidinium phosphate, pyrrolidinium thiocyanate, pyrrolidinium dicyanamide salt, pyrrolidinium benzoate, pyrrolidinium trifluoromethanesulfonate, pyrrolidinium chloride, pyrrolidinium sulfate, pyrrolidinium thiocyanate, pyrrolidinium dicyanamide salt, pyrrolidinium benzoate, pyrrolidinium trifluoromethanesulfonate, and the like, Phosphonium acetate, phosphonium sulfonate, phosphonium chloride, phosphonium sulfate, phosphonium phosphate, phosphonium thiocyanate, phosphonium dicyanamide salt, phosphonium benzoate, phosphonium trifluoromethanesulfonate, sulfonium acetate, sulfonium sulfonate, sulfonium chloride, sulfonium sulfate, sulfonium phosphate, sulfonium thiocyanate, sulfonium dicyanamide salt, sulfonium benzoate, sulfonium trifluoromethanesulfonate, ammonium acetate, ammonium sulfonate, ammonium chloride, ammonium sulfate, ammonium phosphate, ammonium thiocyanate, ammonium dicyanamide salt, ammonium benzoate, ammonium trifluoromethanesulfonate, and mixtures thereof.

In another embodiment, in the adhesive layer, the ionic liquid is selected from the group consisting of 1-ethyl-3-methylimidazolium acetate, 1-ethyl-3-methylimidazolium methanesulfonate, 1-ethyl-3-methylimidazolium trifluoromethanesulfonate, 1-ethyl-3-methylimidazolium chloride, 1-ethyl-3-methylimidazolium ethylsulfate, 1-ethyl-3-methylimidazolium diethylphosphate, 1-ethyl-3-methylimidazolium thiocyanate, 1-ethyl-3-methylimidazolium dicyanamide salt, 1-ethyl-3-methylimidazolium benzoate, choline trifluoromethanesulfonate, choline saccharinate, choline acetaminosulfonate, N-cyclohexylsulfamate, tris (2-hydroxyethyl) methylammonium methylsulfate, 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-allyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide, 1-ethyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide, Choline acetate and mixtures thereof.

Preferably, the ionic liquid is selected from the group consisting of 1-ethyl-3-methylimidazolium acetate, 1-ethyl-3-methylimidazolium methanesulfonate, 1-ethyl-3-methylimidazolium trifluoromethanesulfonate, 1-ethyl-3-methylimidazolium chloride, 1-ethyl-3-methylimidazolium ethylsulfate, 1-ethyl-3-methylimidazolium diethylphosphate, 1-ethyl-3-methylimidazolium thiocyanate, 1-ethyl-3-methylimidazolium dicyanamide salt, 1-ethyl-3-methylimidazolium benzoate, choline trifluoromethanesulfonate, choline saccharinate, choline acetaminosulfonate, choline N-cyclohexylsulfamate, tris (2-hydroxyethyl) methylammonium methylsulfate, 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-allyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide, Choline acetate and mixtures thereof.

More preferably, the ionic liquid is selected from the group consisting of 1-ethyl-3-methylimidazolium benzoate, 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-ethyl-3-methylimidazolium methanesulfonate, 1-ethyl-3-methylimidazolium chloride, 1-ethyl-3-methylimidazolium trifluoromethanesulfonate, choline trifluoromethanesulfonate, 1-ethyl-3-methylimidazolium acetate, choline acetate, 1-ethyl-3-methylimidazolium diethylphosphate, 1-allyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide, 1-ethyl-3-methylimidazolium ethylsulfate, 1-ethyl-3-methylimidazolium thiocyanate, 1-ethyl-3-methylimidazolium dicyanamide, choline saccharinate, choline acetaminosulfonate, and mixtures thereof.

The above ionic liquids are preferred because they show good solubility and low toxicity in the (meth) acrylic polymer according to the present invention.

In one embodiment, two or more ionic liquids are used, in which embodiment the ionic liquid is selected from the group consisting of 1-ethyl-3-methylimidazolium acetate, 1-ethyl-3-methylimidazolium methanesulfonate, 1-ethyl-3-methylimidazolium trifluoromethanesulfonate, 1-ethyl-3-methylimidazolium chloride, 1-ethyl-3-methylimidazolium ethylsulfate, 1-ethyl-3-methylimidazolium diethylphosphate, 1-ethyl-3-methylimidazolium thiocyanate, 1-ethyl-3-methylimidazolium dicyanamide salt, 1-ethyl-3-methylimidazolium benzoate, choline trifluoromethanesulfonate, choline saccharinate, choline acetylaminosulfonate, N-cyclohexylaminosulfonate, tris (2-hydroxyethyl) methylammonium methylsulfate, 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-allyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide, choline acetate;

preferably, the two or more ionic liquids are selected from the group consisting of 1-ethyl-3-methylimidazolium benzoate, 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-ethyl-3-methylimidazolium methanesulfonate, 1-ethyl-3-methylimidazolium chloride, 1-ethyl-3-methylimidazolium trifluoromethanesulfonate, choline trifluoromethanesulfonate, 1-ethyl-3-methylimidazolium acetate, choline acetate, 1-ethyl-3-methylimidazolium diethylphosphate, 1-allyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide, 1-ethyl-3-methylimidazolium ethylsulfate, 1-ethyl-3-methylimidazolium thiocyanate, 1-ethyl-3-methylimidazolium dicyanamide, choline saccharinate, choline acetaminosulfonate.

Suitable commercially available ionic liquids for use in the present invention include, but are not limited to, basitics ST80, basitics Kat1, basitics BC01, basitics VS11, basitics VS03, and Efka IO 6785, all from BASF.

In one embodiment, the ionic liquid is present in the adhesive layer at 0.5 to 50 weight percent, or 1 to 40 weight percent, or 4 to 25 weight percent, based on the total weight of the conductive pressure sensitive adhesive layer.

The adhesive layer according to the present invention may further comprise an ion conductivity promoter, preferably a non-toxic, non-irritating ion conductivity promoter, to create additional ion conductivity.

The ionic conductivity promoter is semi-solid or solid at room temperature and is soluble in the ionic liquid. It has good compatibility with the (meth) acrylate polymers according to the invention.

Suitable ionic conductivity promoters for use in the present invention are selected from the group consisting of choline chloride, choline bitartrate, choline dihydrogen citrate, choline phosphate, choline gluconate, choline fumarate, choline carbonate, choline pyrophosphate, sodium chloride, lithium chloride, potassium chloride, calcium chloride, magnesium chloride, aluminum chloride, silver chloride, ammonium chloride, alkylammonium chloride, dialkylammonium chloride, trialkylammonium chloride, tetraalkylammonium chloride, and mixtures thereof.

In one embodiment, the ionic conductivity promoter is present in the adhesive layer at 0.1 to 30 weight percent, or 0.5 to 20 weight percent, or 1 to 15 weight percent, based on the total weight of the electrically conductive pressure sensitive adhesive layer. If the amount of the ionic conductivity promoter is too small, the adhesive may not exhibit any ionic conductivity and the signal may be lost, while too much may not provide an improvement in the quality of the signal but may increase the chance of skin irritation and decrease the adhesive properties.

The adhesive layer according to the present invention may further comprise conductive particles.

In another embodiment, in the adhesive layer, the electrically conductive particles are selected from the group consisting of metal (nano) particles, graphite (nano) particles, carbon nanowires, electrically conductive polymer (nano) particles, and mixtures thereof, more preferably from the group consisting of silver-containing particles, silver particles, copper-containing particles, silver nanowires, copper nanowires, graphite particles, carbon particles, and mixtures thereof, and even more preferably from the group consisting of graphite particles, carbon particles, and mixtures thereof.

Graphite particles and carbon particles are preferred because of the fact that they do not cause skin irritation, but provide sufficient electrical conductivity. Suitable commercially available conductive particles for use in the present invention include, but are not limited to, Ensaco250G, Timrex KS6 from Timcal, Printex XE2B from Necarbo, C-Nergy Super C65 from Imerys, and Vulcan XC72R from Cabot.

The ion-conductive pressure-sensitive adhesive composition according to the present invention may comprise 0.1 to 35% by weight, preferably 0.5 to 25%, more preferably 1 to 15% by weight of the conductive particles based on the total weight of the composition.

If the amount of the conductive particles is too small, poor conductivity may result, while too much may result in loss of adhesive properties.

The adhesive layer according to the present invention may further comprise a solvent. Preferably, the solvent that may be contained in the adhesive before drying should be volatilized during drying so that the adhesive layer may be formed. In a preferred embodiment, the adhesive layer is substantially free of solvent after the drying step.

Suitable solvents for use in the present invention may be selected from the group consisting of water, ethyl acetate, butyl diglycol, 2-butoxyethanol, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, methanol, isopropanol, butanol, dibasic esters, hexane, heptane, 2, 4-pentanedione, toluene, xylene, benzene, hexane, heptane, methyl ethyl ketone, methyl isobutyl ketone, diethyl ether and mixtures thereof, preferably the solvent is selected from the group consisting of ethyl acetate, butyl acetate, ethylene glycol, propylene glycol and mixtures thereof.

Suitable commercially available solvents for use in the present invention include, but are not limited to, ethyl acetate and ethylene glycol from Brenntag, butyl acetate from Shell Chemicals, and propylene glycol from Lyondell.

The adhesive layer according to the present invention may include 0.001 to 10 wt%, preferably 0.001 to 5 wt%, more preferably 0.01 to 1 wt% of a solvent based on the total weight of the conductive pressure-sensitive adhesive layer (a).

Most preferably, the adhesive layer is substantially free of solvent.

The adhesive layer according to the invention preferably has a resistance value of less than 1,000,000Ohm at 1000Hz, preferably a resistance value of less than 100,000Ohm at 1000Hz and more preferably a resistance value of less than 40,000Ohm at 1000Hz, wherein the resistance is measured by connecting two electrodes, each electrode being coated with a contact area of 0.25cm²25 μm ion-conductive pressure-sensitive adhesive。

The combination of the adhesive layer according to the invention, the (meth) acrylate polymer and the ionic liquid results in a low impedance. The ionic liquid provides ionic conductivity. However, poor ionic conductivity is seen in pressure sensitive adhesives if the ionic liquid is immiscible with the (meth) acrylate polymer. In embodiments where PEG is added to the composition, the additional ether groups from the PEG make the system more polar and enhance the ionic conductivity of the ionic liquid in the (meth) acrylate polymer.

The adhesive layer composition according to the present invention generally has high breathability. Good breathability is obtained if water can easily penetrate into the adhesive layer. To achieve this effect, polar polymers are required, in which case the OH-functional groups support and improve the breathability.

The adhesive layer according to the invention preferably has about 4600g/m within 24 hours²The permeability value of (a). In contrast, a standard acrylic PSA has about 2000g/m over 24 hours²The permeability value of (a). Breathability is measured by Moisture Vapor Transmission Rate (MVTR) measurements according to ASTM D1653-13.

The adhesive layer may be obtained by coating the conductive pressure-sensitive adhesive on a support substrate (such as a film), and drying the layer in an oven at, for example, 120 ℃ for 3 minutes to remove the solvent and form a dried layer of the conductive pressure-sensitive adhesive on the support substrate. Known methods for preparing pressure-sensitive adhesives can be employed. Examples include roll coating, gravure coating, reverse coating, roll brushing, spray and air knife coating methods, dip and curtain coating methods, and extrusion coating methods using a die coater.

In a preferred embodiment, the adhesive layer has a thickness of 1 to 200 μm, or 10 to 50 μm; and/or have a frequency of 10 at 10Hz¹To 10⁷Omega or 10²To 10⁵Impedance value of Ω. Wherein the adhesive layer has a thickness of 0.25cm²To 10cm²Preferably 1cm²To 6cm²Surface area of (a).

The electrode according to the invention comprises a conductive layer, preferably only one conductive layer.

In one embodiment, the conductive layer is selected from a metal or metal salt layer, in particular a copper, silver, gold, aluminum, Ag/AgCl, or carbon layer or a mixture thereof.

In another embodiment, the conductive layer has a thickness of 0.1 to 500 μm, or 0.5 to 150 μm, or 1 to 25 μm, or 1 to 20 μm.

In another embodiment, the conductive layer is the only conductive layer included in the electrode in addition to the conductive pressure sensitive adhesive.

In a preferred embodiment, the electrode according to the invention comprises a substrate. In one embodiment, the substrate is a flexible film, preferably selected from a polyolefin film, a polycarbonate film, a Thermoplastic Polyurethane (TPU) film, a silicone film, a woven film, a nonwoven film or a paper film, in particular a polyethylene film, a polypropylene film, a polyethylene terephthalate film or a thermoplastic polyurethane film.

In another embodiment, the substrate has a thickness of 10 to 500 μm or 25 to 150 μm.

In one embodiment, the conductive layer (B) is a metal, preferably a metal having a thickness of 10 to 500 μm, or 25 to 150 μm. Preferably, the metal is a layer of copper, silver, gold or aluminum.

In order to package the electrode and avoid the adhesive layer sticking to the package, the electrode may comprise a release liner on the surface of the adhesive layer, which is subsequently applied to the area to be measured. All release liners known in the art are suitable, and in one embodiment the release liner is selected from a siliconized paper release liner or a plastic release liner.

As already stated above, the electrode of the present invention does not require a gel/hydrogel. Thus, in one embodiment, the electrode is substantially free of hydrogel, preferably containing more than 0.5 wt.%, or 0.1 wt.%, or 0.001 wt.% of hydrogel, or no hydrogel, based on the total weight of the electrode.

In another embodiment, the electrode is substantially free of an aqueous electrolyte paste, preferably containing more than 0.5 wt.%, or 0.1 wt.%, or 0.001 wt.% of an aqueous electrolyte paste, or no aqueous electrolyte paste, based on the total weight of the electrode.

In another embodiment, the electrode is substantially free of water, preferably does not contain more than 2 wt.%, or 0.5 wt.%, or 0.01 wt.% water, based on the total weight of the electrode, or is free of water.

Impedance is a key parameter of electrode function, and ANSI/AAMI EC12:2000/(R)2015 defines the requirements and measurement procedures for disposable ECG electrodes. For two electrodes attached to each other with their adhesive sides, the impedance requirement of the electrodes at 10Hz is on average below 2000 Ohm. For a suitable conductive layer material, the electrode impedance at 10Hz is determined by the impedance of the binder.

In addition to impedance requirements, medical ECG electrodes must provide some defibrillation overload recovery (measured according to ANSI/AAMI EC12:2000/(R) 2015). Defibrillation overload recovery in this context means that when a 10 muf capacitor (charged to 200V) is discharged through the sample (which consists of two electrodes attached to each other by their adhesive sides; the electrodes here correspond to the adhesive on the Ag/AgCl conductive layer on the non-conductive substrate), the voltage across the electrodes decreases. This must be performed 3 times in succession for a successful test. The allowable voltage ranges are shown in table 1 below, and each value is the maximum allowable voltage at a time or the maximum allowable voltage difference over a time interval:

TABLE 1

Defibrillation overload recovery may be affected by the choice of ionic liquid/salt, especially the anion of the ionic liquid/salt. In particular chloride, provides a rapid defibrillation overload recovery time on Ag/AgCl electrodes. In principle, every chloride can be used, but chlorides of ionic liquids (e.g. EMIM chloride or choline chloride) are preferred because of their good compatibility with the binder material. However, EMIM chloride in the adhesive composition may not result in sufficient bulk conductivity to pass the impedance requirements. Surprisingly, anionic-bearing ionic liquids (e.g., EMIM dicyandiamide) that provide good bulk conductivity do not exhibit rapid defibrillation overload recovery. Therefore, a good balance of ideal electrode behavior between good bulk conductivity and fast discharge characteristics needs to be found. The combination of two or more different ionic liquids or salts in the ionically conductive PSA according to the present invention may be a solution that meets all performance requirements of the electrode.

It has been found that chloride salts already provide fast discharge characteristics in lower amounts (less than 2 wt% of the dry adhesive film according to the invention) because the electrode with the chloride containing adhesive has a DC resistance in the kOhm range, while the electrode with the chloride free adhesive has a DC resistance of about 10 MOhm. Only a low DC resistivity will discharge the sample in a short time and thus the defibrillation overload recovery requirement can be met.

The electrode of the invention is manufactured by a method comprising or consisting of the steps of:

(i) optionally providing a substrate on one side of which a conductive layer is applied by flat screen printing, rotary screen printing, flexography, gravure, pad printing, inkjet printing, LIFT printing, vacuum based deposition methods such as CVC, PVD and ALD, spraying, dipping or immersion plating;

(ii) applying a conductive pressure sensitive adhesive layer on the conductive layer by coating, laminating, spraying or printing; and

(iii) a release liner is optionally applied over the side conductive voltage sensitive adhesive layer.

In one embodiment, in step (ii), the electrically conductive pressure sensitive adhesive layer partially or completely covers the surface of the electrically conductive layer.

Preferably, the electrically conductive pressure sensitive adhesive layer is a printable material. Thus, the layer (a) can be applied in a very easy manner only on a part of the conductive layer (B). Applying a layer only on a part of the conductive layer may increase the gas permeability of the whole electrode, thus even reducing skin irritation.

Thus, in a preferred embodiment, the conductive pressure sensitive adhesive layer is applied only on a portion of the conductive layer. The conductive pressure sensitive adhesive layer may be applied to the conductive layer in different patterns. Preferably, the conductive pressure sensitive adhesive layer does not form a continuous layer on the entire surface of the conductive layer.

In another embodiment, after the conductive pressure sensitive adhesive layer is applied, the layer is cured preferably at 20 to 150 ℃, more preferably at 80 to 130 ℃ for 1 second to 2 hours, preferably 3 seconds to 10 minutes.

In another embodiment, after the conductive layer is applied, the conductive layer is dried preferably at 20 to 200 ℃, more preferably 30 to 150 ℃ for 1 second to 2 hours, preferably 3 seconds to 15 minutes.

The electrode according to the invention is used for monitoring a bio-signal, preferably ECG, EEG, EMG or bio-impedance.

Examples

Materials:

DURO-TAK 222A from AG & Co. KGaA

1-Ethyl-3-methylimidazolium triflate from Proionic

1-Ethyl-3-methylimidazolium dicyanamide salt from BASF

1-Ethyl-3-methylimidazolium chloride from BASF

Example 1 and comparative example 1

Preparation of conductive PSA:

5g of LOCTITE Duro-TAK 222A (solids content: 41%) and 0.171g of 1-ethyl-3-methylimidazolium trifluoromethanesulfonate and 0.057g of 1-ethyl-3-methylimidazolium chloride were mixed in a conditioning mixer at 2000rpm for 3 minutes. The mixture was coated on a release liner and dried at room temperature for 30 minutes, resulting in a PSA film with a thickness of 20 μm. The sample (drawdown) was then cured at 120 ℃ for 3 minutes and covered with another release liner. Preparation of ECG electrodes containing conductive PSA:

the conductive layers were covered with a conductive PSA and adhered together such that the area of the connection was 3.1cm². The electrode pair was connected to the alligator clip and the impedance of the capacitor was measured.

Comparative example 1: 3M Red Dot 2330 resting ECG electrode

Example 1 a: conductive PSA (thickness: 14 μm) on the carbon layer; carbon layer on TPU substrate prepared with LOCTITE ECI 7005E & C

Example 1 b: conductive PSA (thickness: 5 μm) on Ag layer; ag layer prepared with LOCTITE ECI 1010E & C on TPU substrate

Example 1 c: conductive PSA on Ag/AgCl layer (thickness: 12 μm); Ag/AgCl layer on TPU substrate prepared with LOCTITE EDAG 6038E SS E & C

Example 1 d: conductive PSA (thickness: 10 μm) on conductive element from comparative example 1

Figure 3 shows that ECG electrodes comprising conductive PSA (examples 1a-d) according to the present invention have similar impedance spectra compared to a commercial resting ECG electrode (comparative example 1). In all examples, the impedance at 10Hz was below 2000Ohm, meeting the performance requirements according to ANSI/AAMI EC12: 2000.

Figure 3 shows that examples 1a-d result in impedance spectra comparable to commercial conductive elements. Commercial elements were used by removing the hydrogel from the commercial extreme ear electrode. The conductive element obtained was coated with the conductive adhesive according to the present invention and measured as a comparative sample in a capacitor device.

Fig. 4 illustrates a recorded ECG spectrum. ECG signals were recorded using three electrodes (working, counter and reference) placed on the inside of the human forearm (two on the left arm and one on the right arm) and the derivation between the left and right arms was measured. Monitoring is performed while both arms are at rest. Good ECG signals can be obtained in all cases.

Example 2

5g of LOCTITE Duro-TAK 222A (solids content: 41%) and 0.228g of 1-ethyl-3-methylimidazolium trifluoromethanesulfonate were mixed in a conditioning mixer at 2000rpm for 3 minutes. The mixture was coated on a release liner and dried at room temperature for 30 minutes, resulting in a PSA film with a thickness of 20 μm. The sample was then cured at 120 ℃ for 3 minutes and covered with another release liner.

Example 3

5g of LOCTITE Duro-TAK 222A (solids content: 41%) and 0.228g of 1-ethyl-3-methylimidazolium dicyanamide salt are mixed in a mixing blender at 2000rpm for 3 minutes. The mixture was coated on a release liner and dried at room temperature for 30 minutes, resulting in a PSA film with a thickness of 20 μm. The sample was then cured at 120 ℃ for 3 minutes and covered with another release liner.

Example 4

5g of LOCTITE Duro-TAK 222A (solids content: 41%) and 0.228g of 1-ethyl-3-methylimidazolium chloride were mixed in a conditioning mixer at 2000rpm for 3 minutes. The mixture was coated on a release liner and dried at room temperature for 30 minutes, resulting in a PSA film with a thickness of 20 μm. The sample was then cured at 120 ℃ for 3 minutes and covered with another release liner.

Fig. 5 illustrates impedance curves for electrodes with Ag/AgCl conductive layers and binder compositions according to examples 1 (solid line) and 2 (dashed line). The main difference is that the increase at low frequency indicates a lower interfacial (DC) conductivity for example 1.

Fig. 5 illustrates that the impedance spectrum of an electrode with an Ag/AgCl conductive layer without chloride in the binder shows a strong increase in capacitance at low frequencies (corresponding to the presence of the blocking electrode) and thus a high DC resistance, since (almost) no charge transfer occurs across the electrode/binder interface. In contrast, electrodes with chloride containing binders allow for reaction between the Ag/AgCl conductive layer and the electrode binder, resulting in charge transfer (at suitably low voltages), and thus low DC resistance, which enables fast discharge during DOR experiments.

Defibrillation overload recovery was tested for examples 2-4. In this test, the voltage over time during discharge was measured for different electrode binder compositions (example 2 (circle), example 3 (square), example 4 (triangle)) (fig. 6). Fig. 6 illustrates the voltage across the electrodes during discharge. For examples 2 and 3, the voltage was always above 100mV, indicating that no sufficient discharge occurred (condition 2 of table 2 is missed — after 7 seconds <100mV), while sample 4 easily passes the test requirements.

Fig. 7 illustrates three consecutive defibrillation overload recovery discharge curves according to ANSI/AAMI EC12:2000/(R)2015 for an electrode pair having an electrode adhesive according to example 2. A summary of the test conditions for the electrode pairs having electrode binders according to example 2 is shown in table 2 below. Three of the four requirements are not met, indicating the need for an adhesive that allows for faster discharge.

TABLE 2

Fig. 8 illustrates three consecutive defibrillation overload recovery discharge curves according to ANSI/AAMI EC12:2000/(R)2015 for an electrode pair having an electrode adhesive according to example 1. A summary of the test conditions for the electrode pairs having electrode binders according to example 1 is shown in table 3 below.

TABLE 3

All the requirements here are met, which shows the benefit of increasing the DC conductivity to achieve ionic liquids such as chlorides.

ANSI/AAMI EC12:2000/(R)2015 describes that the time of use of the electrodes is limited to only the time that the sample (two electrodes attached to each other by their adhesive sides) can be biased with a 200nA current at a resulting voltage <100 mV. DC offset of >100mV should not be measured. This value is related to the start of the current bias curve.

Fig. 9 illustrates the voltage increase during current biasing for electrode samples with different binder compositions according to the present invention. Example 1-solid line and example 2-dashed line. Example 1 corresponds to a sample with DC conductivity. The voltage is defined by ohm's law. This voltage can be maintained for a long time. Since DC conductivity corresponds to a reversible electrochemical reaction at the interface, the voltage will remain relatively constant as long as the reactants are available at the interface. In the case of example 2, there was no significant DC conductivity at the interface. Thus, the voltage corresponds to the charging of the interface, and the capacitance therefore increases sharply with time.

Electrodes that provide DC conductivity also exhibit longer bias current tolerance and lower DC offset values. Preferably, the electrode binder exhibits DC conductivity and low impedance.

Fig. 10 illustrates the voltage increase during long-time current bias (200nA) of the electrode sample (example 1) having the electrode binder according to the present invention. Due to the long measuring time, the voltage is not recorded continuously here, but only several times per day (weekend break). Sample F, E, C, G corresponds to nominally identical samples that were current biased when connected in series. Therefore, the results were very similar to those expected. The initial change (DC offset) disappeared after two days, resulting in a stable plateau. The voltage started to increase after about 5 days. However, this voltage is still well below the desired 100mV limit. Thus, the test clearly passed (and likely also longer) over the 8 days measured.

Fig. 11 illustrates the voltage increase during long time current bias (2 μ a) for the electrode sample with electrode binder (example 1). 2 mua corresponds to ten times the current required by the standard. The test is intended to identify accelerated tests. The results roughly correspond to the increase that occurred from 40-45 hours. The higher current was taken into account (and the correlation value was calculated to be the flowing charge), which corresponds to 6 days in the standard test (where 5 days were seen). The voltage here is higher (and therefore the onset of the increase may be hidden) due to ohm's law.

ANSI/AAMI EC12:2000/(R)2015 requires a peak-to-peak voltage of less than 150 μ V (after 1 minute of stabilization) to ensure a low noise ECG signal. The AC signal recorded by the ECG system for electrode samples with electrode binders typically has a peak-to-peak voltage below 10 μ V.

Fig. 12 illustrates the offset instability and internal noise of an electrode sample (example 1) having an electrode binder according to the present invention. This measurement corresponds to an ECG measurement with interconnected electrodes instead of the human body. The total bandwidth is about 8 μ V and is therefore much lower than required by the standard (150 μ V).