Conductive pressure-sensitive adhesive

Abstract

The present invention relates to an electrically conductive pressure-sensitive adhesive comprising a copolymer obtained from a reaction mixture comprising an acrylic monomer mixture and a specific styrene derivative, a method for preparing the electrically conductive pressure-sensitive adhesive composition, and a use thereof. The invention also relates to the acrylic monomers themselves, to a method for the production thereof and to the use thereof in polymerization processes.

Description

[0001] The present invention relates to a conductive pressure-sensitive adhesive comprising a copolymer obtained from a reaction mixture comprising an acrylic monomer mixture and a specific styrene derivative, a preparation method of the conductive pressure-sensitive adhesive composition and use thereof.

[0002] Conductive adhesives are mainly used in electronics, especially in technical fields such as aerospace and automotive. In recent years, conductive adhesives have also become interesting for electrodes in medical and diagnostic applications such as electrocardiograms (ECG), electroencephalograms (EEG) and electromyograms (EMG).

[0003] In this regard, US2018 / 086948 provides an adhesive composition comprising a resin and a conductive material, wherein the conductive material is an ammonium salt of a fluorosulfonic acid having 5 or more carbon atoms represented by the following general formula (1): (R 1 —X—Z—SO3 - ) n M n+ , where R 1 represents a linear, branched or cyclic monovalent hydrocarbon group having 1 to 40 carbon atoms and optionally substituted by a heteroatom or optionally inserted with a heteroatom; X represents any one of a single bond, an ether group, an ester group and an amide group; Z represents a linear or branched alkylene group having 2 to 4 carbon atoms, containing 1 to 6 fluorine atoms and optionally containing a carbonyl group; M n+ represents a cation having one or two ammonium cation structures; and when contained in M n+ When the number of ammonium cation structures in M ​​is 1, "n" is 1, or when the number of ammonium cation structures in M ​​is 1, "n" is 1. n+ When the number of ammonium cation structures in is 2, "n" is 2.

[0004] WO 2020 / 178218 discloses an ion-conductive pressure-sensitive adhesive composition comprising a) a (meth)acrylate resin comprising at least 10% by weight of a (meth)acrylate monomer containing an OH group, based on the total weight of the (meth)acrylate resin; and b) an ionic liquid.

[0005] Despite the efforts that have been made, there is still a need for conductive pressure-sensitive adhesives that can be applied to detect biosignals such as heart rate or brain waves, especially in long-term monitoring. Another issue is sustainability, as the materials can usually only be used once.

[0006] In order to solve the above needs, the present invention provides a conductive pressure-sensitive adhesive based on materials obtainable from renewable resources. In this regard, a first aspect of the present invention is a conductive pressure-sensitive adhesive composition comprising a copolymer obtained from a reaction mixture comprising:

[0007] a) a monomeric acrylic mixture; and

[0008] b) Compounds of formula (I):

[0009]

[0010] Where R 1 is a sulfate group (OSO3 - ), sulfonate group (SO3 - ) or a hydrogen atom (H); R 2 is a sulfate group, a sulfonate group, an alkoxy group or a hydrogen atom,

[0011] And where X + is the counterion, provided that R 1 or R 2 is a sulfate group (OSO3 - ).

[0012] During the course of the present invention, it was found that the conductive pressure sensitive adhesive composition of the present invention provides improved ionic conductivity and increased peel strength, even in the absence of commonly used ionic liquids. The composition of the present invention further has the following advantages: the compound of formula (I) can be incorporated into the acrylate polymer backbone.

[0013] The conductive pressure-sensitive adhesive composition according to the present invention can be advantageously used as a dry film, which provides a solution for long-term monitoring of biological signals by acting as a functional contact between an electrode and the skin. Compared with gel-type electrodes currently on the market, it does not have the disadvantages of drying out or causing skin irritation. In addition, without adding any water, the impedance of the conductive pressure-sensitive adhesive composition according to the present invention is very low.

[0014] Counterion X + Preferably selected from the group consisting of:

[0015] NR 3 R 4 R 5 R 6+ , where R 3 , R 4 , R 5 and R 6 Each of which is independently selected from C1-C8-alkyl,

[0016] Optionally substituted imidazolium,

[0017] ·choline,

[0018] · optionally substituted pyridinium,

[0019] Optionally substituted pyrrolidinium,

[0020] · Phosphonium,

[0021] · Sulfonium,

[0022] and mixtures thereof.

[0023] Counterion X + Rather than a mixture of cations, it may be a single species, preferably one selected from those defined above.

[0024] Where X + is NR as defined above 3 R 4 R 5 R 6+ , R 3 , R 4 , R 5 and R 6 Each of R is independently selected from C2-C6-alkyl. 3 , R 4 , R 5 and R 6 are all the same alkyl groups. Preferably, X + It is N(C4H9)4 + .

[0025] When X + When X is an optionally substituted imidazolium, + The options include unsubstituted imidazolium or dialkyl imidazolium. Preferably, X + is a 1,3-dialkylimidazolium, wherein each alkyl group is independently selected from a linear or branched C1-C6 alkyl group, more preferably a linear or branched C1-C3 alkyl group. Preferably, each alkyl group is independently selected from a linear C1-C6 alkyl group, more preferably a linear C1-C3 alkyl group. A particularly suitable group is 1-ethyl-3-methylimidazolium. X + It may also be tris(2-hydroxyethyl)methylammonium or 1-allyl-3-methylimidazolium.

[0026] When X + When X is an optionally substituted pyridinium, + The options include unsubstituted pyridinium or mono-N-substituted pyridinium, such as 1-alkylpyridinium, wherein the alkyl group is selected from linear or branched C1-C6 alkyl, preferably linear or branched C1-C4 alkyl, more preferably linear C1-C4 alkyl. + Disubstituted pyridiniums may also be included, i.e., substituents are present at positions 1,2, 1,3, or 1,4 on the pyridine ring, such as 1,2-alkylpyridinium, 1,3-alkylpyridinium, or 1,4-alkylpyridinium, wherein each alkyl group is independently selected from a linear or branched C1-C6 alkyl group, preferably a linear or branched C1-C4 alkyl group, and more preferably a linear C1-C4 alkyl group.

[0027] In X + In the case of an optionally substituted pyrrolidinium, X + The options include unsubstituted pyrrolidinium or mono-N-substituted pyrrolidinium, such as 1-alkylpyrrolidinium, wherein the alkyl group is selected from linear or branched C1-C6 alkyl, preferably linear or branched C1-C4 alkyl, more preferably linear C1-C4 alkyl. + Disubstituted pyrrolidiniums may also be included. For example, the nitrogen ring members may be disubstituted. For example, X + It may be a 1,1-dialkylpyrrolidinium, wherein each alkyl group is independently selected from a linear or branched C1-C6 alkyl group, preferably a linear or branched C1-C4 alkyl group, and more preferably a linear C1-C4 alkyl group.

[0028] With regard to the groups R1 and R2, R1 is preferably a sulfate group and R2 is an alkoxy group or a hydrogen atom. In a particularly preferred embodiment, R1 is a sulfate group and R2 is a hydrogen atom.

[0029] The alkoxy group of the compound of formula (I), if present, is preferably selected from OMe, OEt, OPr and OBu, with OMe being preferred.

[0030] In a particularly preferred embodiment, the compound of formula (I) is as follows:

[0031]

[0032] Where X + As defined above. Preferably, X + It is N(C4H9)4 + .

[0033] The conductive pressure sensitive adhesive comprises a copolymer obtained from a reaction mixture comprising a monomer acrylic mixture. In a preferred embodiment, the monomer acrylic mixture comprises at least one of methyl methacrylate, hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, acrylic acid, C1-C18 alkyl (meth)acrylates, (meth)acrylamide, vinyl acetate, N-vinyl caprolactam, acrylonitrile, vinyl ether, benzyl (meth)acrylate, cyclohexyl (meth)acrylate, glycidyl (meth)acrylate, and mixtures thereof, preferably formed from monomers selected from the group consisting of hydroxyethyl acrylate, methyl methacrylate, n-butyl acrylate, 2-ethylhexyl acrylate, and mixtures thereof.

[0034] Particularly preferred is the following embodiment of the present invention, wherein the monomer acrylic mixture comprises at least one of the following, preferably all: 2-ethylhexyl acrylate (abbreviation: 2-EHA), methyl methacrylate (abbreviation: MMA), 2-hydroxyethyl acrylate (abbreviation: 2-HEA), n-butyl acrylate (abbreviation: BA).

[0035] In a preferred embodiment of the conductive pressure sensitive adhesive composition according to the invention, the reaction mixture contains 2-EHA in an amount of 1 to 20 wt. %, preferably 2 to 7 wt. %, in the reaction mixture, based on the total weight of the reaction mixture.

[0036] In a preferred embodiment of the conductive pressure sensitive adhesive composition according to the invention, the reaction mixture contains MMA in an amount of 1 to 7 wt %, preferably 2 to 5 wt %, in the reaction mixture, based on the total weight of the reaction mixture.

[0037] In a preferred embodiment of the conductive pressure sensitive adhesive composition according to the invention, the reaction mixture contains 2-HEA in an amount of 15 to 40 wt. %, preferably 20 to 35 wt. %, in the reaction mixture, based on the total weight of the reaction mixture.

[0038] In a preferred embodiment of the conductive pressure sensitive adhesive composition according to the invention, the reaction mixture contains BA in an amount of 40 to 80 wt. %, preferably 55 to 65 wt. %, in the reaction mixture, based on the total weight of the reaction mixture.

[0039] In a preferred embodiment of the conductive pressure-sensitive adhesive composition according to the invention, the compound of formula (I) is contained in the reaction mixture in an amount of 0.1 to 50% by weight, preferably 0.2 to 30% by weight, in particular 0.5 to 10% by weight, based on the total weight of the reaction mixture.

[0040] During the course of the present invention, it was surprisingly found that the addition of an ionic liquid to a conductive pressure sensitive adhesive composition enables faster build-up of peel strength over time compared to compositions containing only an ionic liquid or a compound of formula (I). Therefore, in a preferred embodiment, the conductive pressure sensitive adhesive composition further comprises an ionic liquid.

[0041] The ionic liquid optionally included in the conductive pressure sensitive adhesive composition is preferably a non-toxic, non-irritating ionic liquid that induces ionic conductivity.

[0042] More specifically, the ionic liquid is selected from the group consisting of imidazolium acetate, imidazolium sulfonate, imidazolium chloride, imidazolium sulfate, imidazolium phosphate, imidazolium thiocyanate, imidazolium dicyanamide, imidazolium benzoate, imidazolium triflate, choline triflate, saccharin choline, choline sulfamate, pyridinium acetate, pyridinium sulfonate, pyridinium chloride, pyridinium sulfate, pyridinium phosphate, pyridinium thiocyanate, pyridinium dicyanamide, pyridinium benzoate, pyridinium triflate, pyrrolidinium acetate, pyrrolidinium sulfonate, pyrrolidinium chloride, pyrrolidinium sulfate, pyrrolidinium phosphate, Pyrrolidinium thiocyanate, pyrrolidinium dicyanamide, pyrrolidinium benzoate, pyrrolidinium trifluoromethanesulfonate, phosphonium acetate, phosphonium sulfonate, phosphonium chloride, phosphonium sulfate, phosphonium phosphate, phosphonium thiocyanate, phosphonium dicyanamide, phosphonium benzoate, phosphonium trifluoromethanesulfonate, sulfonium acetate, sulfonium sulfonic acid ammonium acetate, ammonium sulfonate, ammonium chloride, ammonium sulfate, ammonium phosphate, ammonium thiocyanate, ammonium dicyanamide, ammonium benzoate, ammonium triflate, and mixtures thereof.

[0043] 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 ethyl sulfate, 1-ethyl-3-methylimidazolium diethyl phosphate, 1-ethyl-3-methylimidazolium thiocyanate, 1-ethyl-3-methylimidazolium dicyanamide, 1-ethyl-3-methylimidazolium benzoate, choline trifluoromethanesulfonate, choline saccharinate, choline acetylsulfamate, choline N-cyclohexylaminosulfamate, tris(2-hydroxyethyl)methylammonium methylsulfate, 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-allyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, choline acetate, and mixtures thereof.

[0044] 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 diethyl phosphate, 1-allyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, 1-ethyl-3-methylimidazolium ethyl sulfate, 1-ethyl-3-methylimidazolium thiocyanate, 1-ethyl-3-methylimidazolium dicyanamide, saccharin choline, acetamido choline and mixtures thereof.

[0045] In one embodiment of the conductive pressure-sensitive adhesive composition, two or more ionic liquids are used. In this 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 ethyl sulfate, 1-ethyl-3-methylimidazolium diethyl phosphate, 1-ethyl-3-methylimidazolium thiocyanate, 1-ethyl-3-methylimidazolium dicyanamide, 1-ethyl-3-methylimidazolium benzoate, choline trifluoromethanesulfonate, saccharin choline, acetamidosulfonate, N-cyclohexylaminosulfonate choline, tris(2-hydroxyethyl)methylammonium methyl sulfate, 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-allyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, acetic acid choline; 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 diethyl phosphate, 1-allyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, 1-ethyl-3-methylimidazolium ethyl sulfate, 1-ethyl-3-methylimidazolium thiocyanate, 1-ethyl-3-methylimidazolium dicyanamide, saccharin choline, acetamidosulfonate choline.

[0046] In a particularly preferred embodiment, the ionic liquid is selected from the group consisting of 1-ethyl-3-methylimidazolium trifluoromethanesulfonate, 1-ethyl-3-methylimidazolium acetate, 1-ethyl-3-methylimidazolium methanesulfonate, 1-ethyl-3-methylimidazolium chloride, 1-ethyl-3-methylimidazolium sulfate, 1-ethyl-3-methylimidazolium diethyl phosphate, 1-ethyl-3-methylimidazolium thiocyanate, 1-ethyl-3-methylimidazolium dicyanamide, 1-ethyl-3-methylimidazolium benzoate, 1-ethyl-3-methylimidazolium tetrafluoroborate, choline trifluoromethanesulfonate, choline saccharinate, choline acetylsulfamate, choline N-cyclohexylsulfamate, tris(2-hydroxyethyl)methyl The choline chloride is preferably selected from the group consisting of 1-ethyl-3-methylimidazolium trifluoromethanesulfonate, 1-ethyl-3-methylimidazolium acetate, 1-ethyl-3-methylimidazolium methanesulfonate, 1-ethyl-3-methylimidazolium chloride, 1-ethyl-3-methylimidazolium sulfate, 1-ethyl-3-methylimidazolium diethyl phosphate, 1-ethyl-3-methylimidazolium thiocyanate, 1-ethyl-3-methylimidazolium dicyanamide, 1-ethyl-3-methylimidazolium benzoate, 1-ethyl-3-methylimidazolium tetrafluoroborate, choline trifluoromethanesulfonate, saccharin choline, acetylsulfamate choline, choline acetate and mixtures thereof.

[0047] Suitable commercially available ionic liquids for use in the present invention include, but are not limited to, Basionics ST80, Basionics Kat1, Basionics BC01, Basionics VS1 1, Basionics VS03 and Efka IO 6785, all from BASF.

[0048] The ionic liquid is preferably contained in the conductive pressure sensitive adhesive composition in an amount of 0.1 to 35 wt %, preferably 0.5 to 25 wt %, more preferably 1 to 15 wt %, based on the total weight of the composition.

[0049] Suitably, the conductive pressure sensitive adhesive composition comprises a copolymer obtained from a reaction mixture comprising:

[0050] a.2-EHA

[0051] b.MMA

[0052] c.2-HEA

[0053] d.BA

[0054] e. A compound of formula (I); and an ionic liquid.

[0055] Surprisingly, it was found that the best properties of the conductive pressure sensitive adhesive composition are achieved if a mixture of acrylic monomers is used to obtain the copolymer. Therefore, in a preferred embodiment, the conductive pressure sensitive adhesive composition comprises a copolymer obtained from a reaction mixture comprising:

[0056] a. 2-EHA in an amount of 1 to 20 wt%, preferably 2 to 7 wt%

[0057] b. MMA in an amount of 1 to 7 wt %, preferably 2 to 5 wt %

[0058] c. 2-HEA in an amount of 15 to 40 wt %, preferably 20 to 35 wt %.

[0059] d. BA in an amount of 40 to 80% by weight, preferably 55 to 65% by weight

[0060] e. a compound of formula (I) in an amount of 0.1 to 50% by weight, preferably 0.2 to 30% by weight, in particular 0.5 to 10% by weight,

[0061] are each based on the total weight of the reaction mixture; and

[0062] The ionic liquid is used in an amount of 0.1 to 35 wt %, preferably 0.5 to 25 wt %, and more preferably 1 to 15 wt %, respectively based on the total weight of the conductive pressure sensitive adhesive composition.

[0063] In another aspect, the present invention relates to a process for producing a conductive pressure sensitive adhesive composition according to the present invention, the process comprising the following steps:

[0064] a) providing an initial solution and a feed solution of a reaction mixture comprising a monomeric acrylic mixture and a compound of formula (I);

[0065] b) providing an initial solution and a feed solution of an initiator solution;

[0066] c) adding the initial initiator solution to the initial solution of the reaction mixture at ambient temperature;

[0067] d) heating the reaction mixture of step c) to a temperature between 60°C and 120°C, preferably between 70°C and 90°C;

[0068] e) continuously adding a feed solution of the reaction mixture and a feed solution of the initiator solution.

[0069] In a preferred embodiment, step e) of the process according to the invention is carried out over a period of 2 to 8 hours, preferably 3 to 5 hours.

[0070] The initiator used may be any suitable component for initiating polymerization of acrylic and styrene monomers. Preferably, the initiator is selected from the group consisting of: 2,2'-azobisisobutyronitrile, 1,1'-azobis(cyclohexanecarbonitrile), 2,2'-azobis(2-methylpropionic acid) dimethyl ester, 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2-methylbutyronitrile), benzoyl peroxide, tert-butyl hydroperoxide, tert-butyl peracetate, tert-butyl peroxide, tert-butyl peroxybenzoate, tert-butyl peroxyisopropyl carbonate, cumene hydroperoxide, cyclohexanone peroxide, diisopropylbenzene peroxide, lauroyl peroxide. 2,2'-azobisisobutyronitrile (AIBN) is particularly preferred as the initiator.

[0071] The conductive pressure-sensitive adhesive composition of the invention is particularly suitable for contact with human skin and for long-term monitoring of body functions, such as heart rate or brain waves. Therefore, another object of the present invention is the use of the conductive pressure-sensitive adhesive composition according to the invention in skin applications as a contact medium as part of an electrode for measuring biological signals from the skin, sports tapes, transdermal drug patches, permanent adhesive tapes for industrial use and permanent adhesive tapes for construction work. In addition, the conductive pressure-sensitive adhesive is preferably used in applications such as security labels, masking tapes, price labels and / or electrochemical debonding of power equipment.

[0072] The present invention also relates to compounds of formula (I):

[0073]

[0074] Where R1, R2 and X + As defined herein.

[0075] Both R1 and R2 may be sulfate groups. Alternatively, one of R1 or R2 is a sulfate group. Preferably, R1 is a sulfate group and R2 is a hydrogen atom.

[0076] The present invention also provides a process for preparing a compound of formula (I) as defined herein. The process broadly involves preparing a free acid corresponding to a compound of formula (I) or a substituted salt thereof, followed by reacting with a salt based on an appropriate cation (i.e., a base, wherein X + is a cation of compound (I)) to produce a salt of compound (I). Thus, the method may also involve preparing a free acid form of compound (I) and adding a salt based on an appropriate cation (i.e., a base, wherein X + is the desired cation) to produce a salt of compound (I). The method may also involve the preparation of an alternative salt of compound (I), i.e., wherein X + Different from the required X + and with a salt based on an appropriate cation (i.e., where X +A cation exchange is carried out with a base (which is the desired cation) to produce a salt of compound (I).

[0077] Exemplary methods for preparing compounds of formula (IA) include:

[0078] reacting 4-vinylphenol and sulfur trioxide trimethylamine complex to form a reaction mixture,

[0079] Add tetrabutylammonium hydroxide to the reaction mixture,

[0080] and separating the compound of formula (IA)

[0081]

[0082] As will be well understood by those skilled in the art, starting materials and reagents may be appropriately substituted to prepare other compounds falling within the scope of the compounds of formula (I).

[0083] The present invention also relates to the use of compounds of formula (I) as monomers in polymerization processes:

[0084]

[0085] Where R1, R2 and X + As defined herein.

[0086] It will be appreciated from this disclosure that the present invention may also be described by the following statements:

[0087] 1. A conductive pressure sensitive adhesive composition comprising a copolymer obtained from a reaction mixture comprising:

[0088] a) a monomeric acrylic mixture; and

[0089] b) Compounds of formula (I):

[0090]

[0091] Where R 1 is a sulfate group (OSO3 - ), sulfonate group (SO3 - ) or a hydrogen atom (H); R 2 is a sulfate group, a sulfonate group, an alkoxy group or a hydrogen atom, and wherein X + is the counterion, provided that R 1 or R 2 It is a sulfate group.

[0092] 2. A conductive pressure-sensitive adhesive composition according to statement 1, characterized in that R1 is a sulfate group (OSO3 - ).

[0093] 3. The conductive pressure-sensitive adhesive composition according to statement 2, characterized in that R2 is a hydrogen atom.

[0094] 4. The conductive pressure sensitive adhesive composition according to statement 2, characterized in that R2 is an alkoxy group.

[0095] 5. A conductive pressure-sensitive adhesive composition according to statement 1, characterized in that R2 is a sulfate group (OSO3 - ).

[0096] 6. The conductive pressure-sensitive adhesive composition according to Statement 5, characterized in that R1 is a hydrogen atom.

[0097] 7. The conductive pressure sensitive adhesive composition according to statement 5, characterized in that R1 is an alkoxy group.

[0098] 8. A conductive pressure-sensitive adhesive composition according to any one of the preceding statements, characterized in that X + Selected from NR 3 R 4 R 5 R 6+ , where R 3 , R 4 , R 5 and R 6 Each of X is independently selected from C1-C8 alkyl, preferably C2-C6 alkyl, more preferably X + It is N(C4H9)4 + .

[0099] 9. A conductive pressure-sensitive adhesive composition according to any one of the preceding statements, characterized in that X + is an optionally substituted imidazolium.

[0100] 10. A conductive pressure-sensitive adhesive composition according to statement 9, characterized in that X + It is imidazolium.

[0101] 11. A conductive pressure-sensitive adhesive composition according to statement 9, characterized in that X + is a substituted imidazolium, preferably a 1,3-dialkylimidazolium, wherein each alkyl group is independently selected from a linear or branched C1-C6 alkyl group, more preferably a linear or branched C1-C3 alkyl group.

[0102] 12. A conductive pressure-sensitive adhesive composition according to statement 9, characterized in that X + It is a 1,3-dialkylimidazolium, wherein each alkyl group is independently selected from a straight chain C1-C6 alkyl group, preferably a straight chain C1-C3 alkyl group.

[0103] 13. A conductive pressure-sensitive adhesive composition according to statement 9, characterized in that X + It is 1-ethyl-3-methylimidazolium.

[0104] 14. A conductive pressure-sensitive adhesive composition according to any one of statements 1 to 7, characterized in that X + It's choline.

[0105] 15. A conductive pressure-sensitive adhesive composition according to any one of statements 1 to 7, characterized in that X + is an optionally substituted pyridinium.

[0106] 16. A conductive pressure-sensitive adhesive composition according to statement 15, characterized in that X + It is pyridinium.

[0107] 17. A conductive pressure-sensitive adhesive composition according to statement 15, characterized in that X + is a substituted pyridinium, preferably a mono-N-substituted pyridinium or a di-substituted pyridinium, i.e. having a substituent at the 1,2 or 1,3 or 1,4 position on the pyridine ring, more preferably X + It is 1-alkylpyridinium, 1,2-alkylpyridinium, 1,3-alkylpyridinium or 1,4-alkylpyridinium, wherein each alkyl group is independently selected from a linear or branched C1-C6 alkyl group, preferably a linear or branched C1-C4 alkyl group, more preferably a linear C1-C4 alkyl group.

[0108] 18. A conductive pressure-sensitive adhesive composition according to any one of statements 1 to 7, characterized in that X + is an optionally substituted pyrrolidinium.

[0109] 19. A conductive pressure-sensitive adhesive composition according to statement 18, characterized in that X + It is pyrrolidinium.

[0110] 20. The conductive pressure-sensitive adhesive composition according to statement 18, characterized in that X + is a substituted pyrrolidinium, preferably a mono-N-substituted pyrrolidinium or a disubstituted pyrrolidinium, for example, the nitrogen ring member is disubstituted, more preferably a 1-alkylpyrrolidinium or a 1,1-dialkylpyrrolidinium, wherein each alkyl group is independently selected from a linear or branched C1-C6 alkyl group, preferably a linear or branched C1-C4 alkyl group, more preferably a linear C1-C4 alkyl group.

[0111] 21. A conductive pressure-sensitive adhesive composition according to any one of statements 1 to 7, characterized in that X + It's phosphonium.

[0112] 22. A conductive pressure-sensitive adhesive composition according to any one of statements 1 to 7, characterized in that X + It's sulfonium.

[0113] 23. A conductive pressure-sensitive adhesive composition according to any of the preceding statements, characterized in that the (meth)acrylic mixture comprises at least one of the following: methyl methacrylate, hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, acrylic acid, C1-C18 alkyl (meth)acrylates, (meth)acrylamide, vinyl acetate, N-vinyl caprolactam, acrylonitrile, vinyl ether, benzyl (meth)acrylate, cyclohexyl (meth)acrylate, glycidyl (meth)acrylate and mixtures thereof, preferably formed from monomers selected from the group consisting of hydroxyethyl acrylate, methyl methacrylate, n-butyl acrylate, 2-ethylhexyl acrylate and mixtures thereof.

[0114] 24. Conductive pressure-sensitive adhesive composition according to any of the preceding statements, characterized in that the compound of formula (I) is contained in the reaction mixture in an amount of 0.1 to 50% by weight, based on the total weight of the reaction mixture.

[0115] 25. Conductive pressure-sensitive adhesive composition according to any of the preceding statements, characterized in that the compound of formula (I) is contained in the reaction mixture in an amount of 0.2 to 30% by weight, based on the total weight of the reaction mixture.

[0116] 26. Conductive pressure-sensitive adhesive composition according to any of the preceding statements, characterized in that the compound of formula (I) is contained in the reaction mixture in an amount of 0.5 to 10% by weight, based on the total weight of the reaction mixture.

[0117] 27. A conductive pressure-sensitive adhesive composition according to any of the preceding statements, characterized in that the reaction mixture contains 2-EHA in an amount of 1 to 10 wt. % in the reaction mixture, based on the total weight of the reaction mixture.

[0118] 28. A conductive pressure-sensitive adhesive composition according to any of the preceding statements, characterized in that the reaction mixture contains 2-EHA in an amount of 2 to 7% by weight in the reaction mixture, based on the total weight of the reaction mixture.

[0119] 29. A conductive pressure-sensitive adhesive composition according to any of the preceding statements, characterized in that the reaction mixture contains MMA in an amount of 1 to 7 wt. % in the reaction mixture, based on the total weight of the reaction mixture.

[0120] 30. A conductive pressure-sensitive adhesive composition according to any of the preceding statements, characterized in that the reaction mixture contains MMA in an amount of 2 to 5 wt.-% in the reaction mixture, based on the total weight of the reaction mixture.

[0121] 31. A conductive pressure-sensitive adhesive composition according to any of the preceding statements, characterized in that the reaction mixture contains 2-HEA in an amount of 15 to 40% by weight in the reaction mixture, based on the total weight of the reaction mixture.

[0122] 32. A conductive pressure-sensitive adhesive composition according to any of the preceding statements, characterized in that the reaction mixture contains 2-HEA in an amount of 20 to 35% by weight in the reaction mixture, based on the total weight of the reaction mixture.

[0123] 33. A conductive pressure-sensitive adhesive composition according to any of the preceding statements, characterized in that the reaction mixture contains BA in an amount of 40 to 80 wt.-% in the reaction mixture, based on the total weight of the reaction mixture.

[0124] 34. A conductive pressure-sensitive adhesive composition according to any of the preceding statements, characterized in that the reaction mixture contains BA in an amount of 55 to 65 wt.-% in the reaction mixture, based on the total weight of the reaction mixture.

[0125] 35. A conductive pressure-sensitive adhesive composition according to any of the preceding statements, characterized in that the pressure-sensitive adhesive composition further comprises an ionic liquid, which is preferably selected from the group consisting of: 1-ethyl-3-methylimidazolium trifluoromethanesulfonate, 1-ethyl-3-methylimidazolium acetate, 1-ethyl-3-methylimidazolium methanesulfonate, 1-ethyl-3-methylimidazolium chloride, 1-ethyl-3-methylimidazolium sulfate, 1-ethyl-3-methylimidazolium diethyl phosphate, 1-ethyl-3-methylimidazolium thiocyanate, 1-ethyl-3-methylimidazolium dicyanamide, 1-ethyl-3-methylimidazolium benzoate, 1-ethyl-3-methylimidazolium tetrafluoroborate, choline trifluoromethanesulfonate, choline saccharinate, choline acesulfamerate , N-cyclohexylaminosulfonic acid choline, tris(2-hydroxyethyl)methylammonium methylsulfate, acetic acid choline and mixtures thereof, and more preferably selected from the group consisting of: 1-ethyl-3-methylimidazolium trifluoromethanesulfonate, 1-ethyl-3-methylimidazolium acetate, 1-ethyl-3-methylimidazolium methanesulfonate, 1-ethyl-3-methylimidazolium chloride, 1-ethyl-3-methylimidazolium sulfate, 1-ethyl-3-methylimidazolium diethyl phosphate, 1-ethyl-3-methylimidazolium thiocyanate, 1-ethyl-3-methylimidazolium dicyanamide, 1-ethyl-3-methylimidazolium benzoate, 1-ethyl-3-methylimidazolium tetrafluoroborate, choline trifluoromethanesulfonate, saccharin choline, acetylsulfamate choline, acetic acid choline and mixtures thereof.

[0126] 36. The conductive pressure-sensitive adhesive composition according to statement 35, characterized in that the ionic liquid is present in an amount of 0.1 to 35 weight percent based on the total weight of the pressure-sensitive adhesive composition.

[0127] 37. The conductive pressure-sensitive adhesive composition according to statement 35, characterized in that the ionic liquid is present in an amount of 0.5 to 25 weight percent based on the total weight of the pressure-sensitive adhesive composition.

[0128] 38. The conductive pressure-sensitive adhesive composition according to Statement 35, characterized in that the ionic liquid is present in an amount of 1 to 15 weight percent based on the total weight of the pressure-sensitive adhesive composition.

[0129] 39. A conductive pressure-sensitive adhesive composition according to any of the preceding statements, characterized in that the composition comprises a copolymer obtained from a reaction mixture comprising:

[0130] a) 2-EHA in an amount of 1 to 20 wt%, preferably 2 to 7 wt%

[0131] b) MMA in an amount of 1 to 7 wt. %, preferably 2 to 5 wt. %

[0132] c) 2-HEA in an amount of 15 to 40% by weight, preferably 20 to 35% by weight

[0133] d) BA in an amount of 40 to 80 wt. %, preferably 55 to 65 wt. %

[0134] e) a compound of the formula (I) in an amount of 0.1 to 50% by weight, preferably 0.2 to 30% by weight, in particular 0.5 to 10% by weight,

[0135] Based on the total weight of the reaction mixture; and

[0136] 0.1 to 35 wt %, preferably 0.5 to 25 wt %, especially 1 to 15 wt % of ionic liquid, based on the total weight of the pressure-sensitive adhesive composition.

[0137] 40. A method of preparing a conductive pressure sensitive adhesive composition according to any one of Statements 1 to 39, the method comprising the steps of:

[0138] a) providing an initial solution and a feed solution of a reaction mixture comprising a monomeric acrylic mixture and a compound of formula (I);

[0139] b) providing an initial solution and a feed solution of an initiator solution;

[0140] c) adding the initial initiator solution to the initial solution of the reaction mixture at ambient temperature;

[0141] d) heating the reaction mixture of step c) to a temperature between 60°C and 120°C, preferably between 70°C and 90°C;

[0142] e) continuously adding a feed solution of the reaction mixture and a feed solution of the initiator solution.

[0143] 41. The method according to statement 40 is characterized in that the initiator is selected from the group consisting of: 2,2'-azobisisobutyronitrile, 1,1'-azobis(cyclohexanecarbonitrile), 2,2'-azobis(2-methylpropionic acid)dimethyl ester, 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2-methylbutyronitrile), benzoyl peroxide, tert-butyl hydroperoxide, tert-butyl peracetate, tert-butyl peroxide, tert-butyl perbenzoate, tert-butyl peroxyisopropyl carbonate, cumene hydroperoxide, cyclohexanone peroxide, diisopropyl peroxide, and lauroyl peroxide.

[0144] 42. Use of a pressure-sensitive adhesive composition according to any of statements 1 to 39 as a contact medium in skin applications as part of an electrode for measuring biological signals from the skin, a sports tape, a transdermal drug patch, a permanent adhesive tape for industrial use and a permanent adhesive tape for construction work and / or for safety labels, masking tapes, price tags and / or electrochemical debonding for electrical equipment.

[0145] 43. Compounds of formula (I):

[0146]

[0147] Where R 1 is a sulfate group (OSO3 - ), sulfonate group (SO3 - ) or a hydrogen atom (H); R 2 is a sulfate group, a sulfonate group, an alkoxy group or a hydrogen atom, and wherein X + is the counterion, provided that R 1 or R 2 It is a sulfate group.

[0148] 44. A compound according to statement 43, characterized in that R1 is a sulfate group (OSO3 - ).

[0149] 45. A compound according to statement 44, characterized in that R2 is a hydrogen atom.

[0150] 46. ​​A compound according to statement 44, characterized in that R2 is alkoxy.

[0151] 47. A compound according to statement 43, characterized in that R2 is a sulfate group (OSO3 - ).

[0152] 48. A compound according to statement 47, characterized in that R1 is a hydrogen atom.

[0153] 49. A compound according to statement 47, characterized in that R1 is alkoxy.

[0154] 50. A compound according to any one of Statements 43 to 49, characterized in that X + Selected from NR 3 R 4 R 5 R 6+ , where R 3 , R 4 , R 5 and R 6Each of X is independently selected from C1-C8 alkyl, preferably C2-C6 alkyl, more preferably X + It is N(C4H9)4 + .

[0155] 51. A compound according to any one of Statements 43 to 50, characterized in that X + is an optionally substituted imidazolium.

[0156] 52. The compound according to statement 51, characterized in that X + It is imidazolium.

[0157] 53. The compound according to statement 51, characterized in that X + is a substituted imidazolium, preferably a 1,3-dialkylimidazolium, wherein each alkyl group is independently selected from a linear or branched C1-C6 alkyl group, more preferably a linear or branched C1-C3 alkyl group.

[0158] 54. The compound according to statement 53, characterized in that X + It is a 1,3-dialkylimidazolium, wherein each alkyl group is independently selected from a straight chain C1-C6 alkyl group, preferably a straight chain C1-C3 alkyl group.

[0159] 55. The compound according to statement 53, characterized in that X + It is 1-ethyl-3-methylimidazolium.

[0160] 56. A compound according to any one of Statements 43 to 55, characterized in that X + It's choline.

[0161] 57. A compound according to any one of Statements 43 to 56, characterized in that X + is an optionally substituted pyridinium.

[0162] 58. The compound according to statement 57, characterized in that X + It is pyridinium.

[0163] 59. The compound according to statement 57, characterized in that X + is a substituted pyridinium, preferably a mono-N-substituted pyridinium or a di-substituted pyridinium, i.e. having a substituent at the 1,2 or 1,3 or 1,4 position on the pyridine ring, more preferably X + It is 1-alkylpyridinium, 1,2-alkylpyridinium, 1,3-alkylpyridinium or 1,4-alkylpyridinium, wherein each alkyl group is independently selected from a linear or branched C1-C6 alkyl group, preferably a linear or branched C1-C4 alkyl group, more preferably a linear C1-C4 alkyl group.

[0164] 60. A compound according to any one of Statements 43 to 59, characterized in that X + is an optionally substituted pyrrolidinium.

[0165] 61. The compound according to statement 60, characterized in that X + It is pyrrolidinium.

[0166] 62. The compound according to statement 60, characterized in that X + is a substituted pyrrolidinium, preferably a mono-N-substituted pyrrolidinium or a disubstituted pyrrolidinium, for example, the nitrogen ring member is disubstituted, more preferably a 1-alkylpyrrolidinium or a 1,1-dialkylpyrrolidinium, wherein each alkyl group is independently selected from a linear or branched C1-C6 alkyl group, preferably a linear or branched C1-C4 alkyl group, more preferably a linear C1-C4 alkyl group.

[0167] 63. A compound according to any one of Statements 43 to 62, characterized in that X + It's phosphonium.

[0168] 64. A compound according to any one of Statements 43 to 63, characterized in that X + It's sulfonium.

[0169] 65. A compound according to Statement 43, which has the formula (IA)

[0170]

[0171] 66. Use of a compound as defined in any one of statements 43 to 65 as a monomer in a polymerisation process.

[0172] The present invention will be described in more detail with reference to the following examples. However, these should by no means be construed as limiting the scope and spirit of the present invention.

[0173] Embodiment 1:

[0174] i) Preparation of a monomer of the following formula (IA), which is abbreviated hereinafter as SS (styrene sulfate):

[0175]

[0176] The reaction was carried out in a three-necked flask with a reflux condenser and a magnetic stirrer. Under nitrogen, 4-vinylphenol (4-VP, 6.0 g, 50.0 mmol) and sulfur trioxide trimethylamine complex (SO3NMe, 10.5 g, 75.0 mmol, 1.5 equivalents) were added to the flask and dissolved in 60 mL of anhydrous DMF. The reaction was stirred at T = 80°C oil bath temperature for 72 hours.

[0177] The reaction was cooled to room temperature, 1.1 equivalents of tetrabutylammonium hydroxide (TBAOH, 40% aqueous solution) was added and stirred for 1 hour. More water was added and the solution was extracted with DCM. The solvent was evaporated and the product was purified by column chromatography with 95:5 DCM:MeOH. The product was vacuum dried and solidified into an off-white solid. Isolated yield of SS: 60%.

[0178] Embodiment 2:

[0179] i) Preparation of Conductive Pressure Sensitive Adhesive (PSA) Composition

[0180] The compositions of Table 1 were prepared as follows:

[0181] The initiator solution was added to the initial monomer acrylic mixture containing 2-EHA, MMA, 2-HEA, BA and the compound of formula (IA) as described above and heated to 80° C. while stirring. Additional monomer acrylic mixture solution and initiator solution were added continuously. The mixture was then cooled to room temperature and diluted with ethanol, isopropanol and ethyl acetate to obtain the final polymer solution.

[0182] Table 1:

[0183]

[0184] *)contrast

[0185] ii) Preparation of PSA membranes and procedures for impedance measurements

[0186] The PSA films for the property tests were prepared by casting films of the corresponding polymer solutions on silicone paper. After application, the films were dried in an oven at 115°C for 5 minutes and covered with silicone paper. The film thickness was adjusted to obtain a coating weight of ρ A 30g / m 2 For each polymer solution, two 2 x 2 cm test strips were applied. The two substrates were then bonded together at an angle of 180° and a potentiostat was used at 9 × 10 6 The impedance measurements were performed in the frequency range of Hz≤ν≤0.1 Hz. The resistivity ρ was calculated as shown in Equation 1 using the measured impedance Z, the overlap area A and the layer thickness d.

[0187]

[0188] iii) Reducing resistivity by compounds of formula (I)

[0189] The data collected during the impedance measurements are listed in Table 2 and are Figure 1The resistivity of PSA decreases as the content of the compound of formula (I) increases. Since conductivity is defined as the inverse of resistivity, conductivity increases as the content of the compound of formula (I) increases. This may be advantageous for applications in the electronics industry or medical industry (such as ECG medical patches). Figure 1 It can be clearly seen from the data that the resistivity decreases with the increase of SS content.

[0190] Table 2:

[0191]

[0192] Embodiment 3:

[0193] i) Preparation of polymer-ionic liquid blends

[0194] Polymer solutions were prepared as described in Example 2. Ionic liquid (IL) 1-ethyl-3-methylimidazolium triflate was added to prepare polymer-ionic liquid blends. Blends with 5 wt% or 10 wt% ionic liquid relative to the solids content of the polymer solution were prepared.

[0195] ii) Preparation of PSA film for peeling test

[0196] The PSA films for the property tests were prepared by applying the corresponding polymer solutions on etched polyethylene foil. After application, the films were dried in an oven at 115 °C for 5 min and covered with silicone paper. The film thickness was adjusted to obtain a coating weight of A 30g / m 2 membrane.

[0197] iii) 180° peel test sample preparation and procedure

[0198] The 180° peel test was performed according to the protocol FTM1 defined by the European Association of the Self-Adhesive Label Industry (FINAT).

[0199] The data collected in the 180° peel test of the polymer-ionic liquid blends are listed in Table 3 and visualized in Figure 2. In the absence of IL and with 5 wt% IL, the presence of the compound of formula (I) in the polymer increases the adhesion of the PSA on stainless steel and glass substrates. The peel strength increases with the increase of the content of the compound of formula (I). The need for high-performance PSA increases. Figure 2 summarizes the evaluation of the 180° peel test after 24 hours applied on stainless steel (Figure 2A) and glass (Figure 2B). The crude polymer solution (left) and the polymer-ionic liquid blend were tested, and the polymer-ionic liquid blend had 5 wt% IL (right) with 0 wt% (solid), 0.5 wt% (diagonal), 1.5 wt% (horizontal) and 5 wt% (cross lines) of the compound of formula (I). It can be clearly seen from the data provided that on both substrates with and without the addition of IL, the peel strength increases with the increase of the content of the compound of formula (I).

[0200] Table 3:

[0201]

[0202] iv) Synergistic effect of SS and IL on substrate wetting

[0203] The data collected in the 180 ° peel test of polymer-ionic liquid blends are listed in Table 4 and visualized in Figure 3. If there is no comonomer of formula (I) in the polymer, the adhesive needs time to reach its maximum strength, regardless of the addition of ionic liquid, as shown in the significant difference in the peel strength measured 20 minutes and 24 hours after application. The same observations were made for polymers containing 5 wt % of the compound of formula (I) but not containing ionic liquid. However, if IL is added to the polymer with the comonomer of formula (I), the peel strength of 20 minutes after application significantly increases compared to the previously mentioned system. The maximum peel strength is almost reached after 20 minutes. This observation shows the synergistic effect between the presence of the comonomer of formula (I) in the polymer and the IL, which actively affects the wetting process with respect to the shortened application time.

[0204] Referring to Figure 3, there is shown evaluation data of the 180° peel test of the polymer-ionic liquid blends on stainless steel. Figure 3a ) and 10% by weight of a compound of formula (I) ( Figure 3b) were tested 20 minutes (solid) and 24 hours (dashed line) after application. In the absence of the comonomer of formula (I) and in the absence of the IL, a significant difference in the peel strength was observed over time. In the case of the comonomer of formula (I) and the IL, the maximum peel strength was obtained after 20 minutes, which indicates the synergistic effect of the presence of the comonomer of formula (I) in the polymer and the IL on the wetting of the polymer to the substrate.

[0205] Table 4:

[0206]

[0207] The data presented not only show the improved adhesive properties of the conductive pressure sensitive adhesive compositions of the present invention, but also demonstrate the synergistic effects that can be achieved by combining with ionic liquids.

Claims

1. A conductive pressure sensitive adhesive composition comprising a copolymer obtained from a reaction mixture comprising: a) a monomeric acrylic mixture; and b) Compounds of formula (I): Where R 1 is a sulfate group (OSO3 - ), sulfonate group (SO3 - ) or a hydrogen atom (H); R 2 is a sulfate group, a sulfonate group, an alkoxy group or a hydrogen atom, And where X + is the counterion, provided that R 1 or R 2 It is a sulfate group.

2. The conductive pressure sensitive adhesive composition according to claim 1, characterized in that R1 is a sulfate group (OSO3 - ).

3. The conductive pressure sensitive adhesive composition according to claim 2, characterized in that R2 is a hydrogen atom.

4. The conductive pressure sensitive adhesive composition according to claim 1 or 2, characterized in that: R2 is a sulfate group (OSO3 - ).

5. A conductive pressure-sensitive adhesive composition according to any one of the preceding claims, characterized in that X + Selected from NR 3 R 4 R 5 R 6+ , where R 3 , R 4 , R 5 and R 6 Each of which is independently selected from C1-C8 alkyl, preferably C2-C6 alkyl; optionally substituted imidazolium, preferably 1-ethyl-3-methylimidazolium; choline; optionally substituted pyridinium; optionally substituted pyrrolidinium; phosphonium; sulfonium; and mixtures thereof.

6. A conductive pressure-sensitive adhesive composition according to any one of the preceding claims, characterized in that X + YesNR 3 R 4 R 5 R 6+ , where R 3 , R 4 , R 5 and R 6 Each of which is independently selected from C2-C6 alkyl.

7. A conductive pressure-sensitive adhesive composition according to any one of the preceding claims, characterized in that X + It is N(C4H9)4 + .

8. A conductive pressure-sensitive adhesive composition according to any one of the preceding claims, characterized in that The (meth)acrylic mixture comprises at least one of the following: methyl methacrylate, hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, acrylic acid, C1-C18 alkyl (meth)acrylate, (meth)acrylamide, vinyl acetate, N-vinyl caprolactam, acrylonitrile, vinyl ether, benzyl (meth)acrylate, cyclohexyl (meth)acrylate, glycidyl (meth)acrylate and mixtures thereof, and is preferably formed from monomers selected from the following group: hydroxyethyl acrylate, methyl methacrylate, n-butyl acrylate, 2-ethylhexyl acrylate and mixtures thereof.

9. A conductive pressure-sensitive adhesive composition according to any one of the preceding claims, characterized in that The compound of formula (I) is contained in the reaction mixture in an amount of 0.1 to 50% by weight, preferably 0.2 to 30% by weight, in particular 0.5 to 10% by weight, based on the total weight of the reaction mixture.

10. A conductive pressure-sensitive adhesive composition according to any one of the preceding claims, characterized in that The reaction mixture contains 2-EHA in an amount of 1 to 10 wt %, preferably 2 to 7 wt % in the reaction mixture, based on the total weight of the reaction mixture.

11. A conductive pressure-sensitive adhesive composition according to any one of the preceding claims, characterized in that The reaction mixture contains MMA in an amount of 1 to 7 wt. %, preferably 2 to 5 wt. % in the reaction mixture, based on the total weight of the reaction mixture.

12. A conductive pressure-sensitive adhesive composition according to any one of the preceding claims, characterized in that The reaction mixture contains 2-HEA in an amount of 15 to 40 wt %, preferably 20 to 35 wt % in the reaction mixture, based on the total weight of the reaction mixture.

13. A conductive pressure-sensitive adhesive composition according to any one of the preceding claims, characterized in that The reaction mixture contains BA in an amount of 40 to 80 wt.-%, preferably 55 to 65 wt.-% in the reaction mixture, based on the total weight of the reaction mixture.

14. A conductive pressure-sensitive adhesive composition according to any one of the preceding claims, characterized in that The pressure-sensitive adhesive composition further comprises an ionic liquid, which is preferably selected from the group consisting of 1-ethyl-3-methylimidazolium trifluoromethanesulfonate, 1-ethyl-3-methylimidazolium acetate, 1-ethyl-3-methylimidazolium methanesulfonate, 1-ethyl-3-methylimidazolium chloride, 1-ethyl-3-methylimidazolium sulfate, 1-ethyl-3-methylimidazolium diethyl phosphate, 1-ethyl-3-methylimidazolium thiocyanate, 1-ethyl-3-methylimidazolium dicyanamide, 1-ethyl-3-methylimidazolium benzoate, 1-ethyl-3-methylimidazolium tetrafluoroborate, choline trifluoromethanesulfonate, choline saccharinate, choline acetylsulfamate, choline N-cyclohexylsulfamate, tri(2-methylimidazolium)sulfate, choline trifluoromethanesulfon ... -hydroxyethyl)methylammonium methylsulfate, choline acetate and mixtures thereof, and more preferably selected from the following group: 1-ethyl-3-methylimidazolium trifluoromethanesulfonate, 1-ethyl-3-methylimidazolium acetate, 1-ethyl-3-methylimidazolium methanesulfonate, 1-ethyl-3-methylimidazolium chloride, 1-ethyl-3-methylimidazolium sulfate, 1-ethyl-3-methylimidazolium diethyl phosphate, 1-ethyl-3-methylimidazolium thiocyanate, 1-ethyl-3-methylimidazolium dicyanamide, 1-ethyl-3-methylimidazolium benzoate, 1-ethyl-3-methylimidazolium tetrafluoroborate, choline trifluoromethanesulfonate, saccharin choline, acetylsulfamate choline, choline acetate and mixtures thereof.

15. The conductive pressure sensitive adhesive composition according to claim 14, characterized in that The ionic liquid is present in an amount of 0.1 to 35 wt %, preferably 0.5 to 25 wt %, and especially 1 to 15 wt %, based on the total weight of the pressure-sensitive adhesive composition.

16. A conductive pressure-sensitive adhesive composition according to any one of the preceding claims, characterized in that The composition comprises a copolymer obtained from a reaction mixture comprising: a) 2-EHA in an amount of 1 to 20 wt%, preferably 2 to 7 wt% b) MMA in an amount of 1 to 7 wt. %, preferably 2 to 5 wt. % c) 2-HEA in an amount of 15 to 40% by weight, preferably 20 to 35% by weight d) BA in an amount of 40 to 80 wt. %, preferably 55 to 65 wt. % e) a compound of the formula (I) in an amount of 0.1 to 50% by weight, preferably 0.2 to 30% by weight, in particular 0.5 to 10% by weight, Based on the total weight of the reaction mixture; and 0.1 to 35 wt %, preferably 0.5 to 25 wt %, especially 1 to 15 wt % of ionic liquid, based on the total weight of the pressure-sensitive adhesive composition.

17. A method for preparing a conductive pressure sensitive adhesive composition according to any one of claims 1 to 16, the method comprising the following steps: a) providing an initial solution and a feed solution of a reaction mixture comprising a monomeric acrylic mixture and a compound of formula (I); b) providing an initial solution and a feed solution of an initiator solution; c) adding an initial initiator solution to said initial solution of said reaction mixture at ambient temperature; d) heating the reaction mixture of step c) to a temperature between 60°C and 120°C, preferably between 70°C and 90°C; e) continuously adding the feed solution of the reaction mixture and the feed solution of the initiator solution.

18. The method according to claim 17, characterized in that The initiator is selected from the group consisting of: 2,2'-azobisisobutyronitrile, 1,1'-azobis(cyclohexanecarbonitrile), 2,2'-azobis(2-methylpropionic acid)dimethyl ester, 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2-methylbutyronitrile), benzoyl peroxide, tert-butyl hydroperoxide, tert-butyl peracetate, tert-butyl peroxide, tert-butyl perbenzoate, tert-butyl peroxyisopropyl carbonate, cumene hydroperoxide, cyclohexanone peroxide, diisopropyl peroxide, and lauroyl peroxide.

19. Use of a pressure-sensitive adhesive composition according to any one of claims 1 to 16 as a contact medium in skin applications as part of an electrode for measuring biological signals from the skin, sports tapes, transdermal drug patches, permanent adhesive tapes for industrial use and permanent adhesive tapes for construction work, and / or for safety labels for power equipment, masking tapes, price tags and / or electrochemical debonding.

20. Compounds of formula (I): Where R1, R2 and X + As defined in any one of claims 1 to 7.

21. The compound according to claim 20, which has the formula (IA) 22. Use of a compound as defined in claim 20 or 21 as a monomer in a polymerisation process.

Images