Conductive Elastomer Printing Ink for Non-Contact Printing Processes

Abstract

The present invention relates to a conductive crosslinkable silicone elastomer composition as a conductive printing ink in a non-contact printing process for producing electrodes for sensors, actuators or EAP layer systems.

Description

Technical Field

[0001] The present invention relates to a conductive crosslinkable silicone elastomer composition as a conductive printing ink in a non-contact printing process for manufacturing electrodes for sensors, actuators or EAP layer systems.

Background Art

[0002] Conductive printing inks are used in the manufacture of printed electronics and are used to apply electrodes over large areas or in a structured manner on a substrate by any desired printing process in electronic components. Printing of conductive elastomers onto an elastic carrier (such as silicone, TPU, etc.) enables the production of fully or partially elastic electronic components whose electrical properties change little even in the case of stretching or compression. In addition, conductive elastomer printing inks can be printed onto flexible (but not stretchable) substrates such as PET, PE, PTFE or paper, thereby keeping mechanical damage to the printed electrodes low even when mechanical loads due to repeated bending persist, and thus, for example, preventing changes in conductivity due to an increase in resistance. Conductive printing inks for printed electronics are known and some of them are also commercially available. They typically contain at least one polymer binder, at least one conductive component such as metal particles or carbon particles, and at least one solvent for adjusting the viscosity. In principle, conductive carbon particles such as carbon black and carbon nanotubes (CNT) as fillers have the drawback of significantly increasing the viscosity of the formulation, which makes printing this ink much more difficult, resulting in a reduced effective concentration of particles in the printing ink, and therefore a diluting solvent is typically used to enable application of the printing ink. US9253878 describes such a formulation based on silicone elastomer, conductive carbon black and CNT, where the latter is characterized by having a thickness of at least 30 nm. The latter property imparts good printability in screen printing to the solvent-containing conductive printing ink, which is not possible with thin CNT (<30 nm). However, this formulation cannot be done without a solvent.

[0003] US2016351289 states that a silicone-based conductive printing ink must have a solvent content of at least 10% in order to be able to apply the ink. Typically, in the field of silicone printing inks, organic solvents are used, and it is very difficult to completely remove these organic solvents afterwards, which requires high costs for users in terms of occupational safety and environmental protection.

[0004] CNT-containing silicone elastomers are known. CN103160128 describes a silicone elastomer containing both CNTs and carbon black. The silicone elastomers described in this document are characterized by a high proportion of carbon black. At least 3.7 wt% of carbon black is claimed. However, the examples show that a total filler content (CB + CNT) of at least 8.5% is required to obtain good electrical properties such that the resistivity is less than 20 Ω*cm. The printing processes using these compositions are not disclosed.

[0005] Only a few solvent-free silicone-based printing inks are known. For example, US2014060903 describes a solvent-free silicone-based conductive printing ink, but it does not contain any conductive particles (such as carbon nanotubes = CNTs, etc.) with a high aspect ratio and is therefore not suitable for stretchable applications. In stretchable applications including dielectric elastomer sensors, actuators and generators, conductive anisotropic particles with a high aspect ratio, typically CNTs, in combination with a stretchable binder (elastomer) are used. The high aspect ratio of the conductive particles, in contrast to spherical particles, enables the conductive particles to form a conductive network throughout the system with a relatively low filler amount, and this network is ensured to remain even under the stretching and contraction of the elastomer. Therefore, good electron conduction is still guaranteed even in the case of the stretching and contraction of the elastomer.

[0006] Processes known in the prior art for applying a silicone layer, in particular a silicone layer suitable for the manufacture of electrode layers and / or dielectric layers in actuators, sensors and other electroactive polymer layer systems, are limited in terms of their variability, coating accuracy, throughput, as well as in terms of the effectiveness and durability of the components achieved later.

[0007] One of the processes known in the prior art for layer application is what is called laser transfer printing. However, the application of this process has so far been limited to low-viscosity inks and dispersions, as well as metals.

[0008] As an example, WO2009 / 153192A2 describes a method for manufacturing a conductive layer on a semiconductor structure, in which a metal powder dispersion is applied to a carrier and peeled off from the carrier onto a target by a laser beam.

[0009] As an example, WO2010 / 069900A1 describes the laser transfer printing of inks.

[0010] WO2015 / 181810A1 describes a laser transfer process for printing a metal body. This includes selectively heating a metal film on a transparent carrier and placing it in the form of droplets. [Prior Art Documents] [Patent Documents]

[0011] [Patent Document 1] U.S. Patent No. 9,253,878 [Patent Document 2] U.S. Patent Application Publication No. 2016 / 351289 [Patent Document 3] Chinese Patent Application Publication No. 103160128 [Patent Document 4] U.S. Patent Application Publication No. 2014 / 060903 [Patent Document 5] International Publication No. 2009 / 153192

Patent Document 6

Patent Document 7

Summary of the Invention

Problems to be Solved by the Invention

[0012] Therefore, an object of the present invention is to provide a method for producing a conductive crosslinkable silicone elastomer composition that, despite the simultaneous use of conductive carbon black and CNTs having a high aspect ratio, does not involve the use of a solvent and, at the same time, provides a smooth surface free of particles while showing good coating properties as a printing ink after non-contact coating processes such as laser transfer printing, etc.

[0013] Surprisingly, in the present invention, a conductive silicone elastomer composition based on conductive carbon black (0.5 to 3 wt%) and MWCNT (0.1 to 3 wt%) can be used as a printing ink without the addition of a solvent for printing electrodes for dielectric elastomer sensors and actuators when the ink passes through a metal cloth having a mesh size of 200 μm or less (especially 100 μm or less) for pressure filtration before the printing process. The resulting printed image has a smooth surface and no bleeding.

[0014] It is undoubtedly surprising that the filter mesh is not immediately blocked when passing a paste containing particles with a high aspect ratio (length-to-diameter ratio) of (L / B > 10, preferably > 100). This would have resulted in the conductive particles being removed from the paste and thus the filtration process having an adverse effect on the electrical properties of the material. This is not the case. Both the electrical resistance of the uncrosslinked filtered printing ink and the electrical properties of the vulcanized sample therefrom remain constant under stretching and contraction.

[0015] In the description of the present invention, only the preferred embodiments of the individual features are specified below in order not to generate an excessive number of pages.

[0016] However, accordingly, any combination of different levels of preference is clearly disclosed, and the expert reader should clearly understand the method of this disclosure as desired.

Means for Solving the Problems

[0017] Accordingly, the present invention is a method for producing a conductive crosslinkable silicone elastomer composition, wherein the conductive crosslinkable silicone elastomer composition contains the following, - 0.5% to 3.0% by weight of conductive carbon black, - 0.1% to 3.0% by weight of multi-walled carbon nanotubes (MWCNT), - Without solvent, However, a) In the case of a one-component system, all components are mixed in one or more steps, and then pressure filtration is performed by passing through a metal cloth having a mesh size of up to 200 μm, or, b) In the case of a two-component system, in any case, only the components of the A composition or the B composition are mixed in one or more steps, and then, in any case, pressure filtration of the A composition or the B composition is performed by passing through a metal cloth having a mesh size of up to 200 μm, A manufacturing method is provided.

[0018] The MWCNT used according to the present invention preferably has an aspect ratio of L / B > 10, particularly preferably L / B > 100.

[0019] The metal mesh used for pressure filtration preferably has a mesh size of up to 100 μm.

[0020] The method for dispersing the conductive filler, the method for mixing the components, the method for pressure filtration, and the apparatuses that can be used for them are well known to those skilled in the art from the prior art.

[0021] Dispersion is carried out, for example, using a roller mill, a kneader or especially a dissolver (high-speed mixer), and a scraper is also typically used to achieve a uniform distribution of the conductive filler. It is preferable to use a planetary dissolver having a scraper. It is particularly preferable to use a vacuum planetary dissolver having a scraper and a beam stirrer. A dissolver disk having any desired arrangement and number of teeth can be used.

[0022] The base materials used in the silicone elastomer composition can in principle be all silicone elastomer compositions known in the prior art.

[0023] For example, addition-crosslinkable, peroxide-crosslinkable, condensation-crosslinkable or radiation-crosslinkable silicone elastomer compositions can be used. Peroxide-crosslinkable or addition-crosslinkable compositions are preferred. Addition-crosslinkable compositions are particularly preferred.

[0024] The silicone elastomer composition can have a one-component or two-component formulation. Here, the silicone elastomer composition is crosslinked by the supply of heat, UV light and / or moisture. Suitable silicone elastomer compositions include, for example, the following, namely, HTV (addition-crosslinkable), HTV (radiation-crosslinkable), LSR, RTV2 (addition-crosslinkable), RTV2 (condensation-crosslinkable), RTV1, TPSE (thermoplastic silicone elastomer), thiol-ene and cyanoacetamide crosslinking systems.

[0025] In the simplest case, the preferred addition-crosslinkable silicone elastomer composition comprises the following. (A) At least one linear compound containing a group having an aliphatic carbon-carbon multiple bond, (B) At least one, preferably linear, organopolysiloxane compound having Si-bonded hydrogen atoms, Or, instead of (A) and (B), or in addition to (A) and (B), (C) At least one linear organopolysiloxane compound containing an aliphatic carbon-carbon multiple bond and an Si-C bond group having a Si-bonded hydrogen atom, and (D) At least one hydrosilylation catalyst.

[0026] For dispersion, the components of the siloxane composition according to the present invention can be added and dispersed in any desired order.

[0027] In a further preferred embodiment of the process, the conductive carbon black and MWCNT are mixed into a part of the siloxane and optionally dispersed independently of each other, i.e., mixed and dispersed in different mixing vessels, and then the two mixtures (carbon black premix and MWCNT premix) are mixed with any further components and optionally further dispersed. In a further embodiment of the process, one or both of the premixes can be produced using a roller mill.

[0028] It has been found to be advantageous to produce the carbon black premix using a roller mill.

[0029] In a further preferred embodiment of the conductive carbon black and MWCNT of the process, they are mixed together into all or part of the siloxane used and then dispersed together. Here too, instead of the solid carbon black, a pre-produced carbon black premix may be used.

[0030] The amounts of siloxane, conductive carbon black, and MWCNT can be calculated to correspond to the desired solids content of the conductive carbon black and MWCNT in the final mixture, or a so-called masterbatch can also be produced. In the case of a masterbatch, either the amount of siloxane and / or the amount of carbon black and MWCNT is calculated such that the solids content in the mixture is higher than that subsequently required. Both carbon black and MWCNT can be used as solids or in the form of a pre-produced mixture. Once the dispersion is complete, the concentrated solid dispersion can be diluted with additional siloxane to the target value of the solids. This can be done immediately after the dispersion or later, optionally in a different mixing device. The dilution can be carried out using the same siloxane or a different siloxane.

[0031] The addition of MWCNT, carbon black, and components A) to D) can in any case be carried out either little by little or by addition of the total amount, independently of the exact process.

[0032] Prior to the actual dispersion, it may be advantageous to stir or mix the solids into the siloxane at a lower rotational speed of the mixing tool. This makes it possible to achieve a corresponding pre-wetting of the solids by the siloxane.

[0033] The mixing vessel, and thus the mixture present therein, may optionally be temperature-controlled during the dispersion, i.e., maintained at a target temperature by cooling or heating. This temperature is typically in the range of 0 to 200 °C, preferably in the range of 20 to 100 °C.

[0034] The process according to the invention can optionally be carried out under vacuum. The dispersion, i.e., the dispersion interval including dispersion pauses, is preferably carried out under vacuum. The vacuum is typically less than 1000 mbar, preferably less than 800 mbar, and particularly preferably less than 500 mbar.

[0035] It may be further advantageous to apply a vacuum after dispersion. This may be done with the same apparatus as for dispersion or with a different apparatus. The vacuum is typically applied with stirring. The vacuum is typically less than 1000 mbar, preferably less than 800 mbar, particularly preferably less than 500 mbar.

[0036] Subsequently, the dispersion is carried out at a high rotational speed of the dispersion tool, in particular the dissolver disk. The high power input thus achieved results in the desired fine dispersion distribution of the conductive filler, such as MWCNT or carbon black, in the siloxane. The maximum power input of the mixing tool is essential for the dispersion result and thus for the optimally high conductivity of the conductive siloxane mixture. The maximum power input depends on the selected mixing tools, their geometric arrangement, the rotational speed, in particular the rotational speed of the dissolver disk, the temperature and the effective viscosity of the mixture, i.e. the viscosity of the siloxane which depends inter alia on the degree of polymerization of the siloxane and the amount of filler added.

[0037] The invention further provides a conductive crosslinkable silicone elastomer composition obtainable by the method according to the invention.

[0038] The invention further provides the use of a conductive crosslinkable silicone elastomer composition according to the invention as a conductive printing ink in a non-contact printing process for producing a conductive elastomer on an elastic support.

[0039] When the conductive crosslinkable silicone elastomer composition according to the invention produced in this way is used as a printing ink, for example, in a non-contact printing process, a printed image with a smooth surface without particles (spots) is obtained. This is an important advantage when a multilayer system is to be produced (where the conductive material is to be inserted, for example, by lamination or overcoating, between further layers).

[0040] The non-contact printing process has the advantage that the printed substrate is subject to as low a mechanical load as possible during the printing process. The conductive crosslinkable silicone elastomer composition according to the present invention can be used as a printing ink for other non-contact printing processes such as spray processes, drop-on-demand processes or laser transfer printing (LIFT process). It is preferably used in laser transfer printing (LIFT method).

[0041] The conductive crosslinkable silicone elastomer composition according to the present invention is particularly preferably suitable as a printing ink for printing electrodes for dielectric elastomer sensors, actuators and generators and EAP layer systems.

Examples

[0042] The following examples illustrate how the invention can in principle be carried out, but the invention is not limited to that disclosed therein.

[0043] The following examples were carried out at ambient pressure, i.e. about 1013 hPa, and at room temperature, i.e. about 23 °C, or at the temperature established when the reactants were mixed at room temperature without additional heating or cooling, unless otherwise specified.

[0044] <Chemical substances> MWCNT LUCAN BT1001M, LG Chem Ltd., average diameter according to manufacturer's specification: 10 nm

[0045] To produce the carbon black premix, 5 wt% of the highly conductive carbon black Ketjenblack EC-600JD (available from Nouryon) is incorporated into 95 wt% of ViPo 1000 using a three-roll mill.

[0046] ViPo 1000: Vinyl dimethyl siloxy terminated polydimethyl siloxane with a viscosity of 1000 mPa*s available from Gelest Inc., product name DMS-V31 (Gelest catalog)

[0047] HPo 1000: Hydridodimethylsiloxy-terminated polydimethylsiloxane with a viscosity of 1000 mPa*s available from Gelest Inc., product name DMS-H31 (Gelest catalog)

[0048] The crosslinking agent used was α,ω-dimethylhydrogensiloxy-poly(dimethylmethylhydrogen)siloxane (viscosity of 130 - 200 mm 2 / s, H of 0.145 - 0.165 wt%).

[0049] For the one-component system, the selected hydrosilylation catalyst was a platinum complex with a phosphite ligand as described in EP2050768B1 (catalyst 6). For the two-component system, WACKER(R) KATALYSATOR OL (available from Wacker Chemie AG) was used.

[0050] 1-Ethynyl-1-cyclohexanol is available from Sigma Aldrich (CAS number: 78-27-3).

[0051] <Viscosity Measurement> Viscosity measurements were performed at 25 °C using an Anton Paar air-bearing mounted MCR302 rheometer. A cone / plate system (25 mm, 2°) with a gap size of 105 μm was used. Excess material was removed (trimmed) with a spatula at a gap distance of 115 μm. The cone was then moved to a gap distance of 105 μm to fill the entire gap. Prior to each measurement, a pre-shear was performed to erase the shear history resulting from sample preparation, coating, and trimming. The pre-shear was performed at a shear rate of 10 s -1 for 60 seconds, followed by a 300-second rest period. In all cases, the sample was sheared at 1 s -1 、10 s -1 and 100 s -1The shear viscosity is determined by a step profile of shearing for 100 seconds at a constant shear rate. Readings are recorded every 10 seconds to obtain 10 measurement points per shear rate. The average of these 10 measurement points gives the shear viscosity at each shear rate.

[0052] The storage modulus G’ was determined by an amplitude test. In this vibration test, the amplitude γ was varied from 0.01% to 1000% (10s -1 at an angular frequency ω, with a logarithmic slope, 30 measurement points). The linear viscoelastic (LVE) range is typically found at low amplitude values, where the region G’ has a plateau value when plotted double-logarithmically against γ. The plateau value is the storage modulus G’ to be determined.

[0053] <Resistance Measurement> For four-conductor measurements, current is applied to two contacts and the voltage U of the current I already flowing through the sample is measured at two additional contacts, without measuring the contact resistance. U

[0054]

Number

[0055] The resistance R of the unvulcanized siloxane is measured using a Keithley Instruments multimeter model 2110 5 1 / 2 digits, an assembled measuring device made of pure PP, and stainless steel (1.4571) electrodes. The measuring instrument is connected to the electrodes by brass contacts and experimental leads. The measuring device is a mold with dimensions defined for L×W×H of 16 cm × 3 cm × 0.975 cm, into which the siloxane is spread for measurement. Two outer flat electrodes are attached at a distance of 16 cm, thereby ensuring that the current flows through the entire sample. Two point electrodes with a diameter of 1 cm are placed on the base plate at a distance of 12 cm (l) to measure the voltage. The specific resistance is calculated from the measured resistance R using the following formula.

[0056]

Number

[0057] <Change in resistance under expansion and contraction> In accordance with ISO 37, the printing ink was vulcanized in the form of a 2 mm plate, and Type 1 dumbbell test specimens were punched out. Four-conductor measurements were performed on this test specimen. The test specimen was fixed in the center between two conductive clamping jaws, and their distance from each other was set to 84.0 mm. The clamping jaws corresponding to the two outer electrical contacts were structured, thereby achieving the penetration effect (perforation) into the material as a result of this structure.

[0058] Two quick clamps are positioned 25 cm apart from each other, each 29.5 mm away from the nearest clamping jaw, to prepare the two inner contacts. These two inner measurement clamps are pretreated with silver conductive paste. The resistance measured in this way without expansion and contraction (L = L 0 ) is R 0 . The two outer clamping jaws further enable uniaxial expansion and contraction of the test specimen, thus enabling measurement of the resistance R of the printed electrode when the expansion and contraction (L - L 0 ) / L 0 = 50%.

[0059] <Mixing method> In a Labotop 1LA from PC Laborsystem GmbH with a capacity of 1 liter, a mixture was produced at a vacuum of 300 mbar and room temperature. The tools used were a dissolver disk (14 teeth, teeth at 90° to the disk, diameter 52 cm), a beam stirrer (standard tool), and a scraper with temperature measurement. For larger batches, a laboratory mixer (Mischtechnik Hoffmann & Partner GmbH, Andr - Verdun, Austria) with a capacity of 10 L equipped with a toothed dissolver disk (4 teeth, diameter 98 mm), a beam stirrer, and a scraper was used. The double - wall stirring tank was adjusted to a jacket temperature of 19 °C with a thermostat.

[0060] To mix components A and B, a laboratory stirrer (IKA RW20) equipped with a three - blade propeller stirrer (R1381) from IKA(R) - Werke GmbH & Co.KG, Staufen, Germany was used.

[0061] A three - roll mill (model 50l) from EXAKT was used. The roll nip was set to the minimum distance.

[0062] <Filtration> For pressure filtration, the composition was transferred to a cylindrical steel container (capacity 5 L) with an open top and a circular outlet (diameter 31.5 mm) at the base. A double - conical outlet with a circular wire cloth (diameter 80 mm) placed in the center was attached. The pressure plate was lowered, and the composition was vertically extruded through the wire cloth from the steel container at a press pressure of 50 bar. A hydraulic discharge unit from PC Laborsystem was used to lower the pressure plate.

[0063] Wire cloth from PACO Paul GmbH & Co.KG or GKD - Gebr Kufferath AG made of chromium - nickel steel (X5CrNi18 - 10, material number according to DIN / DIN EN 1.4301) with a mesh size of 50 or 25 μm was used.

[0064] [Example 1: Production of Masterbatch M1] In a laboratory mixer with a capacity of 10 L equipped with a toothed dissolution machine disk (diameter 98 mm, 4 teeth), a beam stirrer, and a scraper, a preliminary mixture of MWCNT (36 g) and 1783 g of carbon black was mixed with ViPo 1000 (581 g) at 1800 rpm (dissolution machine) and 50 rpm (beam stirrer) for 60 minutes. The double-wall stirring tank was adjusted to a jacket temperature of 19 °C with a thermostat. A homogeneous black paste with a specific resistance of 5.4 Ω·cm was obtained. This paste had a viscosity of 296 Pa·s at a shear rate of 10 s -1 and a storage modulus G' in the LVE range of 51200 Pa.

[0065] [Example 2: Production of Masterbatch M2] A preliminary mixture of MWCNT (1.0 g) and 50.9 g of carbon black was stirred in ViPo 1000 (16.6 g) using a beam stirrer (80 rpm, Labotop without a dissolution machine disk) for 1 minute, and then incorporated into a three-roll mill twice. A homogeneous black paste with a specific resistance of 6.1 Ω·cm was obtained. This paste had a viscosity of 280 Pa·s at a shear rate of 10 s -1 and a storage modulus G' in the LVE range of 48800 Pa.

[0066] [Example 3: Production of Masterbatch M3] 5.0 g of MWCNT was stirred in 245 g of ViPo 1000 using a beam stirrer (80 rpm, Labotop without a dissolution machine disk) for 1 minute, and then incorporated into a three-roll mill twice. A homogeneous black paste with a specific resistance of 6.9 Ω·cm was obtained. This paste had a viscosity of 80 Pa·s at a shear rate of 10 s -1 and a storage modulus G' in the LVE range of 17000 Pa.

[0067] [Example 4: Production of Printing Ink 1a] In a Labotop 1LA laboratory mixer manufactured by PC Laborsystem GmbH equipped with a toothed dissolution machine disk (diameter 52 mm), a preliminary mixture of 0.8 wt% MWCNT (4.0 g) and 200 g of carbon black was mixed with a mixture of ViPo 1000 (108 g), HPo 1000 (154 g), crosslinking agent (20.0 g), Pt catalyst (0.4 g) and 1-ethynyl-1-cyclohexanol (30 mg) at room temperature, 2000 rpm (dissolution machine) and 200 rpm (beam stirrer) for 60 minutes. The resulting paste was pressed under pressure through a metal cloth having a mesh size of 50 μm. A homogeneous black paste was obtained.

[0068] [Production of Printing Ink 1b in Example 5] Printing ink 1b was prepared in the same manner as printing ink 1a, except that the paste was pressed through a metal cloth having a mesh size of 25 μm.

[0069] [Example 6 Production of Printing Ink 1c (Non-invention)] Printing ink 1c was produced in the same manner as printing ink 1a, except that the paste was not pressed through a metal cloth.

[0070] [Example 7 Production of Printing Ink 2a] The masterbatch M1 from Example 1 was diluted to obtain a platinum-containing component A and a platinum-free component B.

[0071] To produce component A, 1000 g of masterbatch M1 was mixed with ViPo 1000 (855 g) and WACKER(R) KATALYSATOR OL (3.7 g) using a beam stirrer (100 rpm, laboratory mixer without dissolution machine disk) for 30 minutes. Subsequently, the sample was pressed under pressure through a metal cloth (mesh size 50 μm).

[0072] Component B was produced in the same manner as Component A, except that 1000 g of masterbatch M1 was mixed with HPo 1000 (465 g), crosslinking agent (260 g), Vipo 1000 (134 g), and 1-ethynyl-1-cyclohexanol (2.6 g). Subsequently, the sample was pressed through a metal cloth (mesh size 50 μm).

[0073] To produce printing ink 2b, Components A and B were mixed at a 1:1 ratio using a propeller stirrer (800 rpm) for 1 minute. A homogeneous black paste was obtained.

[0074] [Example 8 Production of Printing Ink 2b (Non-Invention)] Printing ink 2b was produced in the same manner as printing ink 2a, except that the two Components A and B were not pressed through the metal cloth before mixing. A homogeneous black paste was obtained.

[0075] [Example 9 Production of Printing Ink 3a] The masterbatch M2 from Example 2 was diluted to obtain a platinum-containing Component A and a platinum-free Component B.

[0076] To produce Component A, 30 g of masterbatch M2 was mixed with Vipo 1000 (25.7 g) and WACKER(R) KATALYSATOR OL (0.11 g) using a beam stirrer (80 rpm, Labotop without dissolution disk) for 30 minutes. Subsequently, the sample was pressed through a metal cloth (mesh size 50 μm) under pressure.

[0077] Component B was produced in the same manner as Component B, except that 30 g of masterbatch M2 was mixed with HPo 1000 (14.0 g), crosslinking agent (7.8 g), Vipo 1000 (4.02 g), and 1-ethynyl-1-cyclohexanol (78 μg). Subsequently, the sample was pressed through a metal cloth (mesh size 50 μm).

[0078] To produce printing ink 3a, Components A and B were mixed at a 1:1 ratio using a propeller stirrer (800 rpm) for 1 minute. A homogeneous black paste was obtained.

[0079] [Example 10 Preparation of Printing Ink 3b (Non-Invention)] Printing Ink 3b was produced in the same manner as Printing Ink 3a, except that the two components were not passed through a metal cloth and pressed before mixing. A homogeneous black paste was obtained.

[0080] [Example 11 Production of Printing Ink 4a] To produce a two-component printing ink, a platinum-containing component A and a platinum-free component B were first produced.

[0081] To produce component A, in a laboratory mixer having a capacity of 10 L equipped with a toothed dissolution machine disk (diameter 98 mm, 4 teeth), a beam stirrer and a scraper, MWCNT (15 g) and 743 g of a carbon black premix were added to a mixture of ViPo 1000 (1097 g) and WACKER(R) KATALYSATOR OL (3.7 g), and mixed at 1800 rpm (dissolution machine) and 50 rpm (beam stirrer) for 60 minutes. The double-wall stirring tank was adjusted to a jacket temperature of 19 °C with a thermostat. Subsequently, sample A was pressed through a metal cloth (mesh size 50 μm) under pressure. Component B was produced in the same manner as component A from MWCNT (15 g), 743 g of a carbon black premix, HPo 1000 (465 g), a crosslinking agent (260 g), Vipo 1000 (373 g) and 1-ethynyl-1-cyclohexanol (2.61 g). Subsequently, sample B was pressed through a metal cloth (mesh size 50 μm) under pressure. To produce Printing Ink 4a, components A and B were mixed at a ratio of 1:1 for 1 minute using a propeller stirrer (800 rpm). A homogeneous black paste was obtained.

[0082] [Example 12 Production of Printing Ink 4b (Non-Invention)] Printing Ink 4b was produced in the same manner as Printing Ink 4a, except that the two components were not pressed through a metal cloth before mixing.

[0083] [Example 13 Production of Printing Ink 5a] 192 g of masterbatch M3 (corresponding to 0.8 wt% MWCNT) and 192 g of carbon black premix were used in a mixture of ViPo 1000 (21.2 g), HPo 1000 (41.4 g) and crosslinking agent (33.6 g), except that the production was carried out in the same manner as the printing ink 1a. The resulting paste was pressed through a metal cloth (mesh size 50 μm) under pressure. A homogeneous black paste was obtained.

[0084] [Example 14 Production of Printing Ink 5b (Non-invention)] Printing ink 5b was produced in the same manner as printing ink 5a, except that the paste was not pressed through a metal cloth.

[0085] [Example 15 Production of Printing Ink 6a] 0.4 wt% MWCNT (2.0 g) and 280 g of carbon black premix (corresponding to 2.8 wt% carbon black in the final formulation) were used in a mixture of ViPo 1000 (48.1 g) and HPo 1000 (150 g), except that the production was carried out in the same manner as the printing ink 1a. The resulting paste was pressed through a metal cloth (mesh size 50 μm) under pressure. A homogeneous black paste was obtained.

[0086] [Example 16 Production of Printing Ink 6b (Non-invention)] Printing ink 6b was produced in the same manner as printing ink 6a, except that the paste was not pressed through a metal cloth.

[0087] [Example 17 Production of Printing Ink 7a] 1.0 wt% MWCNT (5.0 g) and 100 g of carbon black premix (corresponding to 1.0 wt% carbon black in the final formulation) were used in a mixture of ViPo 1000 (221 g) and HPo 1000 (153 g), except that the production was carried out in the same manner as the printing ink 1a. The resulting paste was pressed through a metal cloth (mesh size 50 μm) under pressure. A homogeneous black paste was obtained.

[0088] [Example 18 Production of Printing Ink 7b (Non-Invention)] Printing Ink 7b was produced in the same manner as Printing Ink 7a, except that the paste was not pressed through a metal cloth.

[0089] [Example 19 Production of Printing Ink 8a] Production was carried out in the same manner as Printing Ink 1a, except that 1.2 wt% of MWCNT (6.0 g) and 200 g of a carbon black premix (corresponding to 2.0 wt% of carbon black in the final formulation) were used in a mixture of ViPo 1000 (124 g) and HPo 1000 (150 g). The resulting paste was pressed through a metal cloth (mesh size 50 μm) under pressure. A homogeneous black paste was obtained.

[0090] [Example 20 Production of Printing Ink 8b (Non-Invention)] Printing Ink 8b was produced in the same manner as Printing Ink 8a, except that the paste was not pressed through a metal cloth.

[0091] [Example 21 Production of Printing Ink 9a] Production was carried out in the same manner as Printing Ink 1a, except that 1.5 wt% of MWCNT (7.5 g) and 100 g of a carbon black premix (corresponding to 1.0 wt% of carbon black in the final formulation) were used in a mixture of ViPo 1000 (221 g) and HPo 1000 (152 g). The resulting paste was pressed through a metal cloth (mesh size 50 μm) under pressure. A homogeneous black paste was obtained.

[0092] [Example 22 Production of Printing Ink 9b (Non-Invention)] Printing Ink 9b was produced in the same manner as Printing Ink 9a, except that the paste was not pressed through a metal cloth.

[0093] [Example 23 Production of Printing Ink 10a] 1.2 wt% of MWCNT (2.4 g) and 100 g of a carbon black premix (corresponding to 2.5 wt% of carbon black in the final formulation) were used in a mixture of ViPo 1000 (28.3 g), HPo 1000 (59.3 g), a crosslinking agent (8 g), a Pt catalyst (160 mg), and 1-ethynyl-1-cyclohexanol (12 mg), and the paste was produced in the same manner as Printing Ink 1a except for this. The resulting paste was pressed through a metal cloth (mesh size 50 μm) under pressure. A homogeneous black paste was obtained.

[0094] [Example 24 Production of Printing Ink 10b (Non-invention)] Printing Ink 10b was produced in the same manner as Printing Ink 10a except that the paste was not pressed through a metal cloth.

[0095] [Example 25 Production of Printing Ink 11a] 2.0 wt% of MWCNT (10 g) and 300 g of a carbon black premix (corresponding to 3.0 wt% of carbon black in the final formulation) were used in a mixture of ViPo 1000 (25.3 g) and HPo 1000 (144 g), and the paste was produced in the same manner as Printing Ink 1a except for this. The resulting paste was pressed through a metal cloth (mesh size 50 μm) under pressure. A homogeneous black paste was obtained. A homogeneous black paste was obtained.

[0096] [Example 26 Production of Printing Ink 11b (Non-invention)] Printing Ink 11b was produced in the same manner as Printing Ink 11a except that the paste was not pressed through a metal cloth.

[0097] [Printing Experiment] The LIFT process was carried out as described in WO2020156632. Printing was performed using a commonly used laser engraving system manufactured by TROTEC Laser Deutschland GmbH. A Speedy 100flexx 60 / 20 type system with a dual laser source (60W 10.6μm CO2 laser, 20W 1064nm fiber laser) was used. The carrier and the printing compound carrier used are conventional quartz glass sheets (300×300×3mm) manufactured by GVB GmbH Solution (German glass). A ZAA2300 automatic film plotting unit equipped with a Zehntner GmbH, Switzerland-made ZUA2000 universal applicator was used to apply the printing composition film.

[0098] Using a doctor blade system, a homogeneous layer is centrally applied to one side of the quartz glass sheet with a thickness of 60μm and dimensions of 200×200mm. The edge region of the sheet remains free of the printing compound. A silicone film (ELASTOSIL(R) film with a thickness of 100μm, available from Wacker Chemie AG) fixed to the uncoated glass sheet via a water film is inserted into the laser cutting space as the surface to be printed. The coated sheet is placed on the first sheet with a 200μm gap such that its coated side faces the uncoated sheet. This gap is established using a spacer such as a 100μm microscope slide. The master selected in the control software of the laser system is a two-dimensional filling shape without gray areas and shadows. Furthermore, the laser output in the fiber laser cutting mode is sufficient at 40 - 60% for the 20W laser. The laser speed should be selected between 50% - 70%. The focus should be approximately 4 - 4.5mm above the interface between the coating and the quartz glass sheet. Thus, the selected geometric shape could be transferred onto the silicone film by the laser.

[0099] <Evaluation of the printed matter> The surface of the printed electrode was optically evaluated. The layers printed with printing inks 1a, 1b, 2a, 3a, 4a, 5a, 6a, 7a, 8a, 9a, 10a and 11a were smooth and shiny, with no prominent stains. Therefore, these printing inks are particularly well-suited as electrode materials for multi-layer systems, such as in dielectric elastomer sensors, actuators and generators.

[0100] The layers printed with printing inks 1c, 2b, 3b, 4b, 5b, 6b, 7b, 8b, 9b, 10b and 11b have surfaces with stains protruding from the layers and are therefore not suitable for multi-layer systems.

[0101] The following table compares the amounts of MWCNT and carbon black used in the (Examples), the mesh size used for filtration, and the measurement results.

[0102] [Table 1]

Claims

1. A method for producing a conductive crosslinkable silicone elastomer composition comprising the following, - 0.5% to 3.0% by weight of conductive carbon black - 0.1% to 3.0% by weight of multi-walled carbon nanotubes (MWCNT), - Without solvent, However, a) In the case of a one-component system, all components are mixed in one or more steps and then pressure filtration is carried out by passing through a metal cloth having a mesh size of up to 200 μm, or, b) In the case of a two-component system, in any case, only the components of the A composition or the B composition are mixed in one or more steps and then, in any case, pressure filtration of the A composition or the B composition is carried out by passing through a metal cloth having a mesh size of up to 200 μm.

2. The method according to claim 1, characterized in that the produced conductive crosslinkable silicone elastomer composition is a conductive addition-crosslinkable silicone elastomer composition and contains the following components. (A) At least one linear compound containing a group having an aliphatic carbon-carbon multiple bond, (B) At least one organopolysiloxane compound having Si-bonded hydrogen atoms, Or, instead of (A) and (B), or in addition to (A) and (B), (C) At least one linear organopolysiloxane compound containing an Si-C bond group having an aliphatic carbon-carbon multiple bond and an Si-bonded hydrogen atom, and (D) At least one hydrosilylation catalyst.

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