One component (1K) curable adhesive composition

Abstract

This invention relates to a curable and electrochemically debondable one-component (1K) adhesive composition comprising, based on the weight of the composition: 40 to 90 wt% of i) at least one olefinic unsaturated nonionic monomer; 1 to 30 wt% of ii) a nonpolymerizable electrolyte; 0.1 to 10 wt% of iii) at least one free radical generating thermal initiator; 0 to 20 wt% of iv) a filler; and 0 to 20 wt% of v) a toughening agent.

Description

Technical Field

[0001] This invention relates to adhesive compositions that can be self-applied to a specific substrate for debonding. More specifically, this invention relates to a one-component (1K) curable and electrochemically debonding adhesive composition based on (meth)acrylate monomers. Prior Technology

[0002] Adhesive bonding and polymer coatings are commonly used in the assembly and final processing of products. They replace mechanical fasteners (such as screws, bolts, and rivets) to provide bonding with reduced machining costs and greater adaptability in the manufacturing process. Adhesive bonding distributes stress evenly, reducing the likelihood of fatigue and sealing joints against corrosive species.

[0003] While adhesive bonding offers many advantages over mechanical fasteners, it tends to make disassembly of the bonded objects difficult, which is necessary in practical applications. Removal of adhesives via mechanical processes (such as sandblasting or wire brushing) is often hindered, partly because the adhesive is embedded between substrates and therefore inaccessible to the substrate surfaces and / or difficult to abrade without damaging them. Disassembly by applying chemicals and / or high temperatures (as disclosed in U.S. Patent Nos. 4,171,240 (Wong) and 4,729,797 (Linde et al.) can be effective, but can be time-consuming and complex; furthermore, the aggressive chemicals and / or the required harsh conditions can damage the separating substrates, rendering them unsuitable for subsequent applications.

[0004] Noting these issues, some authors have sought to develop electrochemically debonded adhesive compositions in which an electric current is passed through the cured composition to break the bond at the interface between the adhesive and the substrate.

[0005] WO2007 / 142600 (Stora Enso AB) describes an electrochemically weakening adhesive composition that provides adhesive adhesion to a conductive surface and sufficient ionic conductivity to weaken the adhesive adhesion when a voltage is applied across the adhesive composition, wherein the composition comprises an effective amount of at least one ionic compound to provide the ionic conductivity and wherein the ionic compound has a melting point not greater than 120°C.

[0006] EP 3363875 A (Nitto Denko) provides an electrically removable adhesive composition that forms an adhesive layer with high adhesion and can be easily peeled off after a short period of time with applied voltage. The electrically removable adhesive composition of this invention comprises a polymer and 0.5 to 30% by weight of an ionic liquid based on the polymer, wherein the anion of the ionic liquid is a bis(fluorosulfonyl)imidine anion.

[0007] WO2017 / 133864 (Henkel AG and Co. KGaA) describes a method for reversibly bonding a first substrate and a second substrate, wherein at least the first substrate is a non-conductive substrate, the method comprising: a) coating the surface of the (etc.) non-conductive substrate with a conductive ink; b) applying an electrically descalable hot melt adhesive composition to the conductive ink-coated surface of the first substrate and / or the second substrate; c) contacting the first substrate with the second substrate such that the electrically descalable hot melt adhesive composition is inserted between the two substrates; d) allowing an adhesive bond to be formed between the two substrates to provide a bonded substrate; and e) applying a voltage to the bonded substrate, thereby substantially reducing the adhesion at the interface between the electrically descalable hot melt adhesive composition and the substrate surface. []

[0008] WO2013 / 135677 (Henkel AG and Co. KGaA) describes a hot melt adhesive containing: 20 to 90% by weight of at least one polyamide having a molecular weight (Mw) of 10,000 to 250,000 g / mol; 1 to 25% by weight of at least one organic or inorganic salt; and 0 to 60% by weight of other additives, wherein the adhesive has a softening point of 100°C to 220°C.

[0009] US 2007 / 0269659 (Gilbert) describes an adhesive composition that is debonded at two interfaces, the composition (i) comprising a polymer and an electrolyte; (ii) promoting the bonding of two surfaces; and (iii) debonding from both the anode and cathode surfaces in response to a voltage applied across the two surfaces to form an anodic interface and a cathode interface.

[0010] US 2008 / 0196828 (Gilbert) describes a hot melt adhesive composition comprising: a thermoplastic component; and an electrolyte, wherein the electrolyte provides sufficient ionic conductivity to the composition to enable a Faraday reaction at the adhesive site formed between the composition and a conductive surface and to allow the composition to de-adhere from the surface.

[0011] U.S. Patent No. 7,465,492 (Gilbert) describes an electrochemically debonding composition comprising: a matrix functionality comprising a monomer selected from the group consisting of acrylic acid, methacrylic acid, and combinations thereof; a free radical initiator; and an electrolyte, wherein the electrolyte provides sufficient ionic conductivity to the composition to support a Faraday reaction at the adhesion formed between the composition and a conductive surface and thus allows the composition to debond from the surface. In this reference, the electrolyte comprises a salt solvable into the composition and is a member of the group consisting of ammonium (NH₄⁺), alkali metals, alkaline earth, or rare earth salts, of the anions of perchlorate, tetrafluoroborate, hexafluorophosphate, trifluoromethanesulfonate, and trifluoromethanesulfonylimine.

[0012] There is still a need in this technology for providing curable one-component (1K) adhesive compositions that can be easily applied to the surface of substrates to be bonded, and after curing, can provide effective bonding within such substrates containing composite structures, but can be effectively debonded from such substrates by easily applying a potential across the cured adhesive. Summary of the Invention

[0013] According to a first aspect of the present invention, a curable and electrochemically debondable one-component (1K) adhesive composition is provided, comprising, by weight of the composition: 40 to 90% by weight, preferably 60 to 90% by weight and even more preferably 70 to 90% by weight of (i) at least one olefinic unsaturated nonionic monomer; ii) Non-polymerizable electrolyte, 0.1 to 30% by weight, preferably 1 to 20% by weight; iii) at least one free radical generation thermal initiator, 0.1 to 10% by weight, preferably 0.1 to 5% by weight; 0 to 20% by weight, preferably 0.5 to 10% by weight of (iv) filler; and 0 to 20% by weight, preferably 0.5 to 20% by weight, more preferably 0.5 to 15% by weight of the toughening agent.

[0014] In certain embodiments of the composition, the (meth)acrylate monomers constitute at least 60 mol% and preferably at least 75 mol% of the total molar amount of the olefinic unsaturated nonionic monomers. Preferably, the (meth)acrylate monomers comprise C1-C6 hydroxyalkyl esters of (meth)acrylic acid. Independent of this preference statement or its supplements, preferably, the (meth)acrylate monomers comprise one or more oligomers selected from the group consisting of urethane (meth)acrylates, polyester (meth)acrylates, and polyether (meth)acrylates. Particular preference may be mentioned for the inclusion of at least one urethane (meth)acrylate oligomer in the composition.

[0015] Although the diversity of electrolytes will be discussed in this paper, good results have been obtained in the group consisting of 1-ethyl-3-methyl-1H-imidazol-3-onium methanesulfonic acid, 1-ethyl-3-methylimidazolium trifluoromethanesulfonic acid, 1-ethyl-3-methyl-1H-imidazol-3-onium methylsulfate, and mixtures thereof.

[0016] In key embodiments, the composition of the present invention may contain at least one of iv) the filler or v) the toughening agent. The presence of both the filler and the toughening agent may, for example, promote adhesion between the composition and the substrate surface.

[0017] According to a second embodiment of the present invention, an adhesive structure is provided, comprising: A first material layer having a conductive surface; and A second material layer with a conductive surface, The curable electrochemically debonded single-component (1K) adhesive composition, as defined above and in the claims of the appended patent application, is disposed between the first material layer and the second material layer.

[0018] According to a third aspect of the present invention, a method is provided for debonding an adhesive structure as defined above and in the appended claims, the method comprising the following steps: i) Applying a voltage across the two surfaces to form an anode interface and a cathode interface; and ii) Debond the surfaces.

[0019] Step i) of this method is preferably characterized by at least one of the following: a) Apply a voltage of 0.5 to 200 V; and b) The duration of the applied voltage is from 1 second to 60 minutes.

[0020] The adhesive properties of the composition are disrupted by the application of a potential across the adhesive lines between the composition and the conductive surface. Without being confined to theory, it is assumed that a Faraday reaction occurring at the interface between the adhesive composition and the conductive surface disrupts the interaction between the adhesive and the substrate, thereby weakening the bond. This interface disruption can result from one or more processes, such as chemical degradation of the adhesive material, gas escape at the interface, and / or material embrittlement, despite changes in the crosslinking density of the adhesive composition. [] Simple Explanation of the Diagram

[0021] The present invention will be described with reference to the accompanying drawings, in which:

[0022] Figure 1a illustrates the bonding structure according to a first embodiment of the present invention.

[0023] Figure 1b illustrates the bonding structure according to a second embodiment of the present invention.

[0024] Figure 2a illustrates the initial debonding of the structure after an electric current is passed through it in the first embodiment.

[0025] Figure 2b illustrates the initial debonding of the structure after an electric current is passed through it across the structure of the second embodiment. Implementation

[0026] definition As used herein, unless the context clearly indicates otherwise, the singular forms “a (a / an)” and “the” contain a plural of indicators.

[0027] As used herein, the terms "comprising / comprises / computed of" are synonymous with "including / includes" and "containing / contains," and are inclusive or open-ended and do not exclude other undescribed members, elements, or method steps.

[0028] As used herein, the term "composed of" excludes any unspecified element, component, member, or method step.

[0029] When equivalents, concentrations, dimensions and other parameters are expressed in the form of ranges, preferred ranges, upper limits, lower limits or preferred upper and lower limits, it should be understood that any range that can be obtained by combining any upper or preferred value with any lower or preferred value is specifically disclosed, regardless of whether the obtained range is explicitly mentioned in the context.

[0030] Additionally, according to the standard interpretation, the weight range expressed as "0 to x" specifically includes 0% by weight: the component defined by this range may be absent from the composition or may be present in the composition in an amount of up to x% by weight.

[0031] The terms “preferred,” “more preferably,” “desirably,” and “particularly” are frequently used herein to refer to embodiments of the invention that may provide particular benefits in certain circumstances. However, the detailed description of one or more preferred, preferred, desired, or particular embodiments does not imply that other embodiments are unavailable and is not intended to exclude such other embodiments from the scope of the invention.

[0032] As used throughout this application, the word "may" is used in a permissive sense – that is, meaning possible, not mandatory.

[0033] As used in this article, room temperature is 23°C plus or minus 2°C.

[0034] To describe the macromolecular, oligomer, and polymer components of the curable composition, the molecular weights mentioned in this specification can be measured using gel permeation chromatography (GPC) with polystyrene calibration standards, such as according to ASTM 3536.

[0035] Unless otherwise specified, the viscosity of the compositions described herein was measured using a Brookfield viscometer under standard conditions of 20°C and 50% relative humidity (RH). The Brookfield viscometer calibration method, spindle type, and rotation speed should be selected according to the manufacturer's instructions for the composition to be measured.

[0036] As used herein, the term "electrochemically debonded" means that after the adhesive has cured, the bond strength decreases by at least 50% after a 30 V potential is applied for 20 minutes. The cured adhesive is applied between two substrates bonded by the adhesive, allowing current to flow through the adhesive bond lines. Bond strength is measured at room temperature using a tensile lap shear (TLS) test based on the ASTM D3163-01 standard test method for determining the strength of an adhesive-bonded rigid plastic lap-shear joint under tensile load shear. The bond overlap area is 2.5 cm x 1.0 cm (1" x 0.4"), with a bond thickness of 0.15 cm (60 mils).

[0037] As used herein, the term "monomer" refers to a substance that can undergo polymerization to promote the chemical structure of the constituent units into a polymer. As used herein, the term "monofunctional" refers to having one polymerizable moiety. As used herein, the term "polyfunctional" refers to having more than one polymerizable moiety.

[0038] In this document, the term "electrolyte" is used in accordance with its standard meaning in this art as a substance containing free ions that can conduct electricity through the displacement of a carrier substance. This term is intended to include molten electrolytes, liquid electrolytes, semi-solid electrolytes, and solid electrolytes, wherein at least one of the cation or anionic components of its electrolyte structure is substantially free to displace, thus serving as a carrier.

[0039] The curable adhesive composition of the present invention and the cured adhesive obtained therefrom have "electrolyte functionality" because the adhesive material allows for the conduction of ions (anions, cations, or both). It should be understood that the electrolyte functionality stems from the ability of the composition and the cured adhesive to solvate at least one polar ion.

[0040] The term "Faraday reaction" refers to an electrochemical reaction in which materials are oxidized or reduced.

[0041] As used herein, "(meth)acrylic" is a shorthand term for "acrylic" and / or "methacrylic". Therefore, "(meth)acrylate" is collectively referred to as acrylate and methacrylate.

[0042] As used herein, "C1-Cn alkyl" refers to a monovalent group containing 1 to n carbon atoms, i.e., an alkane group and an organic group comprising straight and branched chains. Therefore, "C1-C18 alkyl" refers to a monovalent group containing 1 to 18 carbon atoms, i.e., an alkane group and an organic group comprising straight and branched chains. Examples of alkyl groups include (but are not limited to): methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, dibutyl, tributyl, n-pentyl, n-hexyl, n-heptyl, and 2-ethylhexyl. In this invention, such alkyl groups may be unsubstituted or may be substituted with one or more halogens. Where applicable to a given part (R), the tolerance of one or more non-halogen substituents within the alkyl group will be specified in this specification.

[0043] As used herein, the term "C1-C18 hydroxyalkyl" refers to a HO-(alkyl) having 1 to 18 carbon atoms, wherein the substituent is attached through an oxygen atom and the alkyl group is as defined above.

[0044] "Alkoxy" refers to a monovalent group represented by -OA, where A is an alkyl group: non-limiting examples include methoxy, ethoxy, and isopropoxy. As used herein, the term "C1-C18 alkoxyalkyl" refers to an alkyl group having an alkoxy substituent as defined above, wherein the moiety (alkyl-O-alkyl) comprises a total of 1 to 18 carbon atoms: such groups include methoxymethyl (-CH2OCH3), 2-methoxyethyl (-CH2CH2OCH3), and 2-ethoxyethyl.

[0045] As used herein, the term "C2-C4 alkyl" is defined as a saturated divalent hydrocarbon group having 2 to 4 carbon atoms.

[0046] The term "C3-C18 cycloalkyl" should be understood to mean a saturated monocyclic or polycyclic hydrocarbon group having 3 to 18 carbon atoms. In this invention, such cycloalkyl groups may be unsubstituted or may be substituted with one or more halogens. Where applicable to a given part (R), the tolerance of one or more non-halogen substituents within the cycloalkyl group will be specified in this specification. Examples of cycloalkyl groups include: cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, adamantyl, and norbornyl.

[0047] As used herein, "C6-C18 aryl" alone or as a majority part—such as in "aralkyl"—refers to monocyclic, bicyclic, and tricyclic ring systems, wherein the monocyclic ring system is aromatic or at least one of the rings in the bicyclic or tricyclic ring system is aromatic. Bicyclic and tricyclic ring systems comprise benzofused 2- to 3-membered carbon rings. In this invention, such aryl groups may be unsubstituted or may be substituted with one or more halogens. Where applicable to a given part (R), the tolerance of one or more non-halogen substituents within the aryl group will be specified in this specification. Exemplary aryl groups include: phenyl; (C1-C4)alkylphenyl, such as tolyl and ethylphenyl; indenyl; naphthyl, tetrahydronaphthyl, tetrahydroindenyl; tetrahydroanthrayl; and anthracel. It may be noted that phenyl is preferred.

[0048] As used herein, "C2-C24 alkenyl" refers to a hydrocarbon group having 2 to 24 carbon atoms and at least one alkenyl unsaturated unit. The alkenyl group can be straight-chain, branched-chain, or cyclic and may be substituted with one or more halogens, as appropriate. Where applicable to a given part (R), the tolerance of one or more non-halogen substituents within the alkenyl group will be specified in this specification. The term "alkenyl" also includes groups having "cis" and "trans" configurations, or, alternatively, "E" and "Z" configurations, as understood by those skilled in the art. Generally, however, a preference should be specified for unsubstituted alkenyl groups containing 2 to 10 (C2-10) or 2 to 8 (C2-8) carbon atoms. Examples of such C2-C12 alkenyl groups include (but are not limited to): -CH=CH2, -CH=CHCH3, -CH2CH=CH2, -C(=CH2)(CH3), -CH=CHCH2CH3, -CH2CH=CHCH3, -CH2CH2CH=CH2, -CH=C(CH3)2, -CH2C(=CH2)(CH3), -C(=CH2)CH2CH3, -C(CH3)=CHCH3, -C(CH3)CH=CH2, -CH=CHCH2CH2CH3, -CH2CH=CHCH2CH3, -CH2CH2CH=CHCH3, -CH2CH2CH2CH=CH2, -C(=CH2)CH2CH2CH3, -C(CH3)=CHCH 2CH 3, -CH(CH 3)CH=CHCH, -CH(CH 3)CH 2CH=CH 2, -CH 2CH=C(CH 3) 2, 1-cyclopent-1-enyl, 1-cyclopent-2-enyl, 1-cyclopent-3-enyl, 1-cyclohex-1-enyl, 1-cyclohex-2-enyl, and 1-cyclohex-3-enyl.

[0049] As used herein, "alkylaryl" refers to an alkyl-substituted aryl group, and "substituted alkylaryl" refers to an alkylaryl group having one or more substituents, such as halogen, nitro, cyano, acetamyl, amino, sulfonyl, sulfinyl, thioalkyl, thiooxy, urea, thiourea, aminesulfonyl, sulfonylamine, and hydroxyl. Additionally, as used herein, "aralkyl" means an alkyl group substituted with an aryl group as defined above.

[0050] As used herein, the term "hetero" refers to a group or part containing one or more heteroatoms (such as N, O, Si, and S). Thus, for example, "heterocyclic" refers to a cyclic group having, for example, N, O, Si, or S as a part of its ring structure. "Heteroalkyl," "heterocycloalkyl," and "heteroaryl" portions are alkyl, cycloalkyl, and aryl groups as defined above, each containing N, O, Si, or S as a part of its structure.

[0051] The compositions of this invention may be defined herein as "substantially free" of certain compounds, elements, ions, or other similar components. The term "substantially free" is intended to mean that compounds, elements, ions, or other similar components are not intentionally added to the composition and are present at most in trace amounts that will not have an (adverse) effect on the desired properties of the coating. An exemplary trace amount is less than 1000 ppm by weight of the composition. The term "substantially free" includes embodiments where the specified compounds, elements, ions, or other similar components are either completely absent from the composition or present in any amount measurable by techniques generally used in this art.

[0052] 1. Nonionic matrix monomer The compositions of the present invention comprise 40 to 90% by weight of at least one olefinic unsaturated nonionic monomer based on the weight of the composition, which (co)polymerizes to produce a matrix capable of debonding adhesives. Preferably, the composition comprises 60 to 90% by weight, for example 70 or 75 to 90% by weight of the at least one olefinic unsaturated nonionic monomer. These monomers can, in principle, be any olefinic unsaturated nonionic monomer. However, the present invention is particularly applicable to compositions in which the total molar amount of the olefinic unsaturated nonionic monomer present as a (meth)acrylate monomer is at least 60 molars, preferably at least 75 molars.

[0053] [] 1.1 (Meth)acrylate monomers There is no particular intention in this document to limit the use of (meth)acrylates or to consider (meth)acrylate monomers to be any ester of acrylic acid or methacrylic acid known in this art. Nevertheless, exemplary (meth)acrylate monomers include (but are not limited to): ● C1-C18 alkyl esters of (meth)acrylate, such as methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate (all isomers), hexyl (meth)acrylate, n-heptyl (meth)acrylate, n-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-nonyl (meth)acrylate, n-decyl (meth)acrylate, n-dodecyl (meth)acrylate, and n-stearyl (meth)acrylate; ● C3-C18 cycloalkyl esters of (meth)acrylate, such as cyclohexyl (meth)acrylate and isobornyl (meth)acrylate; ● C6-C18 aryl esters of (meth)acrylic acid, such as phenyl (meth)acrylic acid and toluene (meth)acrylic acid; ● C7-C24 aryl esters of (meth)acrylate, such as benzyl (meth)acrylate; ● C1-C18 alkoxyalkyl esters of (meth)acrylic acid, such as 2-methoxyethyl (meth)acrylic acid, 2-ethoxyethyl (meth)acrylic acid, and 3-methoxybutyl (meth)acrylic acid; ● Fluorinated C1-C18 alkyl esters of (meth)acrylic acid, such as trifluoromethyl methacrylate, 2-trifluoromethyl ethyl methacrylate, 2-perfluoroethyl methacrylate, 2-perfluoroethyl-2-perfluorobutyl ethyl methacrylate, 2-perfluoroethyl methacrylate, perfluoromethyl methacrylate, diperfluoromethyl methacrylate, 2-perfluoromethyl-2-perfluoroethyl methacrylate, 2-perfluorohexyl ethyl methacrylate, 2-perfluorodecyl ethyl methacrylate, and 2-perfluorohexadecyl ethyl methacrylate; ● C1-C18 hydroxyalkyl esters of (meth)acrylic acid and, more specifically, C1-C6 hydroxyalkyl esters of (meth)acrylic acid, such as 2-hydroxyethyl (meth)acrylic acid, 2-hydroxypropyl (meth)acrylic acid and pentaerythritol tri(meth)acrylic acid; ● Di / polyfunctional alcohols and their di / polyesters, such as ethylene glycol di(meth)acrylate, 1,3 or 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, and trimethylolpropane tri(meth)acrylate; ● C1-C18 aminoalkyl esters of (meth)acrylic acid, such as 2-aminoethyl (meth)acrylic acid, dimethylaminoethyl (meth)acrylic acid, and (meth)acryloxyethoxyethylamine; ● C1-C18 alkoxysilane esters of (meth)acrylic acid, such as γ-(methacryloyloxypropyl)trimethoxysilane; ● (Meth)acrylic acid adducts of ethylene oxide or propylene oxide; and ● (Meth)acrylates formed by alcohols having other functional groups, such as tetrahydrofuran (meth)acrylate.

[0054] For completeness, it is not excluded that the composition may contain a macromonomer component consisting of one or more oligomers selected from the group consisting of urethane (meth)acrylates, polyester (meth)acrylates, and polyether (meth)acrylates. However, such oligomers (which may be monofunctional or polyfunctional relative to polymerizable (meth)acrylates, but are based on repeating urethane, ester, and ether subunits) should generally not constitute more than 30% by weight of the total (meth)acrylate monomers in the composition.

[0055] As is known in this art, urethane (meth)acrylate oligomers can be prepared by reacting a hydroxyl-containing polyfunctional (meth)acrylate with a polyisocyanate as defined above. Specifically, the hydroxyl-containing polyfunctional (meth)acrylate may be selected from the group consisting of: 2-hydroxyethyl (meth)acrylate, 2-hydroxyisopropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, hydroxyethylcaprolactone (meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and combinations thereof.

[0056] Suitable polyester (meth)acrylate oligomers are obtained by reacting (meth)acrylic acid with polyesters prepared from polybasic acids or their anhydrides and polyols. Examples of polybasic acids include (but are not limited to) phthalic acid, succinic acid, adipic acid, glutaric acid, sebacic acid, isosebacic acid, tetrahydrophthalic acid, hexahydrophthalic acid, dimer acids, benzotriic acid, pyrocyanic acid, pimecrolic acid, and azelaic acid. Examples of polyols include (but are not limited to): 1,6-hexanediol, diethylene glycol, 1,2-propanediol, 1,3-butanediol, neopentyl glycol, dipropylene glycol, polyethylene glycol, and polypropylene glycol.

[0057] As is known in the art, polyether (meth)acrylate oligomers can be obtained by transesterification between a polyether and a (meth)acrylate (such as ethyl methacrylate). Exemplary polyethers include those obtained by ethoxylation or propoxylation of trimethylolpropane, pentaerythritol or the like, or by polyetherification with 1,4-propanediol or the like.

[0058] In a preferred embodiment, the composition comprises at least one (meth)acrylate monomer selected from the group consisting of: methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, tributyl methacrylate, n-pentyl methacrylate, n-hexyl methacrylate, cyclohexyl methacrylate, n-heptyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate, nonyl methacrylate, decyl methacrylate, and dodecyl methacrylate. Ester, phenyl methacrylate, toluene methacrylate, benzyl methacrylate, 2-methoxyethyl methacrylate, 3-methoxybutyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, stearyl methacrylate, glycidyl methacrylate, isobornyl methacrylate, 2-aminoethyl methacrylate, γ-(meth)acryloxypropyltrimethoxysilane, methacrylate-ethylene oxide adduct, trifluoromethyl methacrylate, 2-trifluoromethyl methacrylate, methacrylate 2-Perfluoroethyl ethyl acrylate, 2-Perfluoroethyl-2-perfluorobutyl ethyl acrylate, 2-Perfluoroethyl acrylate, Perfluoromethyl acrylate, Di-Perfluoromethyl methacrylate, 2-Perfluoromethyl-2-perfluoroethyl methacrylate, 2-Perfluorohexyl ethyl acrylate, 2-Perfluorodecyl ethyl acrylate, 2-Perfluorohexadecyl ethyl acrylate, Ethoxylated trimethylolpropane triacrylate, Trimethylolpropane trimethacrylate, Dipentaerythritol monohydroxypentaacrylate, Pentaerythritol triacrylate, Ethoxylated trimethylolpropane triacrylate Acrylates, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, pentaerythritol tetraacrylate, 1,2-butanediol diacrylate, trimethylolpropane ethoxylated tri(meth)acrylate, propoxylated tri(meth)acrylate glyceryl ester, trimethylolpropane tri(meth)acrylate, dipentaerythritol monohydroxypenta(meth)acrylate, tripropylene glycol di(meth)acrylate, propoxylated neopentyl glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, triethylene glycol di(meth)acrylate, butylene glycol di(meth)acrylate, and ethoxylated bisphenol A di(meth)acrylate.

[0059] When the composition contains at least one (meth)acrylate monomer selected from the group consisting of C1 to C6 hydroxyalkyl esters of (meth)acrylate, good results are obtained.

[0060] 1.2 Copolymerizable acid As specified above, the composition may, where appropriate, contain at least one copolymerizable acid. When used, the acid may be added in an amount of up to 40 mol% of the total molar amount of the olefinic unsaturated nonionic monomers, for example, up to 20 mol%. For example, the at least one copolymerizable acid may constitute 0 to 15 mol% of the total molar amount of the olefinic unsaturated nonionic monomers. For completeness, although these monomers should generally be used in the form of free acids, the presence of acid groups in monomers that have been appropriately alkali-neutralized or completely neutralized is not excluded, provided that this does not impair their participation in copolymerization.

[0061] Without limiting the invention, the copolymerizable acid monomer should be selected from: olefinic unsaturated carboxylic acids, olefinic unsaturated sulfonic acids, and vinyl phosphoric acid. Suitable olefinic unsaturated sulfonic acids are, for example, vinyl sulfonic acid, styrene sulfonic acid, and acrylamide methylpropanesulfonic acid.

[0062] Preferably, the at least one copolymerizable acid in the composition comprises or is composed of an olefinic unsaturated carboxylic acid selected from the group consisting of: α,β-mono-olefinic unsaturated monocarboxylic acid, α,β-mono-olefinic unsaturated dicarboxylic acid, C1-C6 alkyl half-esters of α,β-mono-olefinic unsaturated dicarboxylic acid, α,β-mono-olefinic unsaturated tricarboxylic acid, and C1-C6 alkyl esters of α,β-mono-olefinic unsaturated tricarboxylic acid having at least one free carboxylic acid group, and mixtures thereof. Specifically, the at least one copolymerizable acid in the composition comprises or is composed of an olefinic unsaturated carboxylic acid selected from the group consisting of: methacrylic acid, acrylic acid, itaconic acid, maleic acid, aconitic acid, crotonic acid, fumaric acid, and mixtures thereof.

[0063] 1.3 Other monomers It should be noted that the present invention does not exclude the presence of vinyl monomers in the composition, such monomers being copolymerizable with (meth)acrylate monomers and selected from the group consisting of: styrene monomers, such as styrene, vinyltoluene, α-methylstyrene, and chlorostyrene; fluorinated vinyl monomers, such as perfluoroethylene, perfluoropropylene, and fluorinated vinyl groups; silicone vinyl monomers, such as vinyltrimethoxysilane and vinyltriethoxysilane; maleimide monomers, such as maleimide, methylmaleimide, ethylmaleimide, propylmaleimide, and butylmaleimide. Imines, hexylmaleimine, octylmaleimine, dodecylmaleimine, stearylmaleimine, phenylmaleimine, and cyclohexylmaleimine; nitrile-containing vinyl monomers, such as acrylonitrile and methacrylonitrile; amide-containing vinyl monomers, such as acrylamide and methacrylamide; vinyl esters, such as vinyl acetate, vinyl propionate, vinyl pentanoate, vinyl benzoate, and vinyl cinnamate; olefins, such as ethylene and propylene; conjugated dienes, such as butadiene and propylene; and vinyl chloride, vinylidene chloride, allyl chloride, and allyl alcohol.

[0064] [] 2. Non-polymerizable electrolytes The composition comprises 0.1 to 30% by weight of a nonpolymerizable electrolyte based on the weight of the composition: the nonpolymerizable electrolyte preferably constitutes 1 to 20% by weight, for example 1 to 15% by weight, of the composition.

[0065] The non-polymerizable electrolyte preferably comprises at least one salt having a formula selected from the group consisting of: Wherein: R1, R2, R3, R4, R5 and R6 are independently selected from hydrogen, C1-C18 alkyl, C3-C18 cycloalkyl, C6-C18 aryl, C7-C24 aralkyl, C2-C20 alkenyl, -C(O)Rq, -C(O)OH, -CN and -NO2; and R q is a C1-C6 alkyl group.

[0066] When using ammonium salts, the condition is that at most three of the groups R1 to R4 and at most two of them may be hydrogen. []

[0067] For completeness, the terms C1-C18 alkyl, C3-C18 cycloalkyl, C6-C18 aryl, C7-C24 aralkyl, and C2-C20 alkenyl explicitly include groups in which one or more hydrogen atoms are substituted with a halogen atom (e.g., C1-C18 haloalkyl) or a hydroxyl group (e.g., C1-C18 hydroxyalkyl). Specifically, preferably, R1, R2, R3, R4, R5, and R6 are independently selected from hydrogen, C1-C12 alkyl, C1-C12 haloalkyl, C1-C12 hydroxyalkyl, and C3-C12 cycloalkyl. For example, R1, R2, R3, R4, R5, and R6 may be independently selected from hydrogen, C1-C6 alkyl, C1-C6 haloalkyl, and C1-C6 hydroxyalkyl. []

[0068] There is no particular intention to limit the counterions (X-) that can be used in non-polymerizable electrolytes. Exemplary anions may be selected from: [] ● Halogen ions; ● Halogen ions and halogen-containing compounds such as PF6-, CF3SO3-, (CF3SO3)2N-, CF3CO2-, and Cl3CO2-; ● CN-, SCN-, and OCN-; ● Phenol group; ● Sulfate, sulfite, and sulfonate ions of the general formulas SO₄²⁻, HSO₄⁻, SO₃²⁻, HSO₃⁻, RaOSO₃⁻, and RaSO₃⁻; ● Phosphate groups of the general formulas PO₄³⁻, HPO₄²⁻, H₂PO₄⁻, RaPO₄²⁻, HRaPO₄⁻, and RaRbPO₄⁻; ● Phosphonate and phosphonite groups of the general formulas RaHPO3-, RaRbPO2-, and RaRbPO3-; ● General formulas: phosphate groups of PO₃³⁻, HPO₃²⁻, H₂PO₃⁻, RaPO₃²⁻, RaHPO₃⁻, and RaRbPO₃⁻; ● Hypophosphite and hypophosphite of the general formulas RaRbPO₂⁻, RaHPO₂⁻, RaRbPO₂⁻, and RaHPO₂⁻; ● Carboxylic acid anion of general formula RaCOO-; ● Hydroxycarboxylic acid anions and glycoacid anions; ● Saccharin (a salt of sulfadiazine); ● Borates of the general formulas BO33-, HBO32-, H2BO3-, RaRbBO3-, RaHBO3-, RaBO32-, B(OR a)(OR b)(OR c)(OR d)-, B(HSO4)- and B(RaSO4)-; ● Borate ions of the general formulas RaBO₂²⁻ and RaRbBO⁻; ● Carbonates and carbonates of the general formulas HCO3-, CO32- and RaCO3-; ● Silicates and silicates of the general formulas SiO₄⁴⁻, HSiO₄³⁻, H₂SiO₄²⁻, H₃SiO₄⁻, RaSiO₄³⁻, RaRbSiO₄²⁻, RaRbRcSiO₄⁻, HRaSiO₄²⁻, H₂RaSiO₄⁻, and HRaRbSiO₄⁻; ● Alkyl silicates and aryl silicates of the general formulas RaSiO3 3-, RaRbSiO2 2-, RaRbRcSiO-, RaRbRcSiO3-, RaRbRcSiO2- and RaRbSiO3 2-; ● Pyridine and pyrimidine salts; ● Carboxylic acid imines, bis(sulfonylurea) imines, and sulfonylurea imines of the following general formulas: ● Methylates of the following general formulas: ; ● Alkyl oxides and aromatic oxides of the general formula RaO-; and ● Sulfides, hydrogen sulfides, polysulfides, and thiolates of general formulas S²⁻, HS⁻, [Sv]²⁻, [HSv]⁻, and [RaS]⁻ In this general formula v is a positive integer from 2 to 10. Ra, Rb, Rc, and Rd are independently selected from hydrogen, C1-C12 alkyl, C5-C12 cycloalkyl, C5-C12 heterocycloalkyl, C6-C18 aryl, and C5-C18 heteroaryl.

[0069] Based on the definitions in the above list, preferred anions are selected from the following groups: halides; halides and halogen-containing compounds as defined above; carboxylic acid anions, specifically formate, acetate, propionate, butyrate, and octanoate; hydroxycarboxylic acid anions, such as lactate; pyridinium and pyrimidine; carboxylic acid imines, bis(sulfonyl)imines, and sulfonylimines; sulfates, specifically methyl sulfate and ethyl sulfate; sulfite; sulfonates, specifically methanesulfonate; and phosphates, specifically dimethyl phosphate, diethyl phosphate, and di-(2-ethylhexyl) phosphate.

[0070] The nonpolymerizable electrolyte of the composition is preferably selected from the group consisting of: 1-ethyl-3-methyl-1H-imidazol-3-onium methanesulfonate, 1-ethyl-3-methyl-1H-imidazol-3-onium methylsulfate, 2-(2-fluoroanilino)pyridine-1-hexyl-3-methylimidazolium, 1-hexyl-3-methylimidazolium nitriloide, 2-(2-fluoroanilino)pyridine-1-butyl-1-methyl-pyrrolidone, 1-butyl-1-methyl-pyrrolidone nitriloide, 2-(2-fluoroanilino)pyridine-1-butyl-1-methyl-pyrrolidone, 1-butyl-1-methyl-pyrrolidone nitriloide, 2-(2-fluoroanilino)pyridine-1-butyl-1-methyl-pyrrolidone nitriloide, 2-(2-fluoroanilino)pyridine-1-methyl ...1-methyl-pyrrolidone nitriloide, 2-(2-fluoroanilino)pyridine-1 Aniline-pyridinetrihexyl(tetradecyl)phosphonium, cyclohexyltrimethylammonium bis(trifluoromethanesulfonyl)imidine, di(2-hydroxyethyl)ammonium trifluoroacetate, N,N-dimethyl(2-hydroxyethyl)ammonium octanoate, methyltrioctylammonium bis(trifluoromethanesulfonyl)imidine, N-ethyl-NNNN-tetramethyltrifluoromethanesulfonate, trifluoromethanesulfonate, 1-butyl-4-methylpyridinium bromide, 1-butyl-3-methylpyridinium tetrafluoroborate, 1-butyl-3-hydroxymethylpyridinium ethyl sulfate, 1 1-Butyl-1-methylpyrrolidone bis(trifluoromethylsulfonylmethane)imidine, tris(pentafluoroethyl)trifluorophosphate 1-butyl-methylpyrrolidone, ethyl sulfate 3-methylimidazolium, 1-ethyl-3-methylimidazolium chloride, 1-ethyl-3-ethyl-methylimidazolium bromide, 1-butyl-3-methylimidazolium chloride, 1-hexyl-3-methylimidazolium chloride, 1-octyl-3-methylimidazolium chloride, 1-methyl-3-octylimidazolium chloride, 1-propyl-3-methylimidazolium iodide Azazole, 1-butyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium trifluoromethanesulfonate, 1-butyl-3-methylimidazolium hexafluorophosphate, 1-ethyl-3-methylimidazolium trifluoromethanesulfonate, 1-butyl-2,3-dimethylimidazolium tetrafluoroborate, 1-butyl-2,3-dimethylimidazolium hexafluorophosphate, 1-butylimidazolium, 1-methylimidazolium tetrafluoroborate, tetrabutylphosphonium trifluorophosphate (pentafluoroethyl)trifluorophosphate, trihexyl(tetradecyl)phosphonium tetrafluoroborate, and mixtures thereof. It may be mentioned that the use of at least one of 1-ethyl-3-methylimidazolium chloride, 1-ethyl-3-methyl-1H-imidazolium methanesulfonate, 1-ethyl-3-methylimidazolium trifluoromethanesulfonate and 1-ethyl-3-methyl-1H-imidazolium methylsulfate is particularly preferred.

[0071] 3. Thermal initiator The compositions of the present invention comprise at least one thermal initiator for free radical generation. As will be understood by those skilled in the art, a thermal initiator is a compound that can be activated by thermal energy to generate its free radicals upon heating or irradiation in the infrared or microwave wavelength region, for example. The compositions of the present invention should conventionally comprise 0.1 to 10% by weight, for example 0.1 to 5% by weight or 0.1 to 2.5% by weight of the at least one thermal initiator for free radical generation, based on the total weight of the composition.

[0072] Without being intended to limit the invention, exemplary categories of free radical generation thermal initiators used herein are selected, for example, organic peroxides selected from cyclic peroxides, diacyl peroxides, dialkyl peroxides, hydroperoxides, peroxy carbonates, peroxy dicarbonates, peroxy esters, and peroxy ketals.

[0073] While certain peroxides (such as dialkyl peroxides) have been disclosed as usable initiators, particularly in U.S. Patent Nos. 3,419,512 (Lees) and 3,479,246 (Stapleton), and are indeed practically applicable herein, hydroperoxides represent a preferred class of initiators for this invention. Furthermore, although hydrogen peroxide itself can be used, most desired polymerization initiators are organic hydroperoxides. For completeness, hydroperoxides are included within the definition of organic peroxides or organic peresters, which decompose or hydrolyze to form organic hydroperoxides in situ: examples of such peroxides and peresters are cyclohexyl and hydroxycyclohexyl peroxides and tributyl perbenzoate, respectively.

[0074] In embodiments of the present invention, the free radical generation thermal initiator comprises or consists of at least one hydroperoxide compound represented by the following formula: R pOOH Wherein: Rp is an aliphatic or aromatic group containing up to 18 carbon atoms, and Preferably, Rp is a C1-C12 alkyl, C6-C18 aryl, or C7-C18 aryl.

[0075] Exemplary peroxide initiators that can be used alone or in combination include: cumene hydroperoxide (CHP), p-menthane hydroperoxide, tert-butyl hydroperoxide (TBH), tert-butyl perbenzoate, tert-butyl perpentanoate, di-tert-butyl peroxide, tert-butyl peracetate, tert-butyl peroxy-2-hexanoate, tert-pentyl hydroperoxide, 1,2,3,4-tetramethylbutyl hydroperoxide, benzoyl peroxide, and di-butyl peroxide. Benzyl, 1,3-bis(tert-butylperoxyisopropyl)benzene, diacetyl peroxide, butyl 4,4-bis(tert-butylperoxy)valerate, p-chlorobenzene peroxide, tert-butyl peroxide, ditert-butyl peroxide, diisopropylbenzene peroxide, 2,5-dimethyl-2,5-ditert-butylperoxyhexane, 2,5-dimethyl-2,5-ditert-butyl-peroxyhex-3-yne and 4-methyl-2,2-ditert-butylperoxypentane.

[0076] Without limiting the invention, another exemplary class of free radical generation thermal initiators used herein is selected from, for example, azo polymerization initiators such as azo nitrile, azo ester, azo amide, azomididine, azo imidazoline, and macroazo initiators.

[0077] Representative examples of suitable azo polymerization initiators include: 2,2'-azobis(2-methylbutyronitrile), 2,2'-azobis(isobutyronitrile), 2,2'-azobis(2,4-dimethylpentanonitrile), 2,2'-azobis(4-methoxy-2,4-dimethylpentanonitrile), 1,1'-azobis(cyclohexane-1-carboxynitrile), 4,4'-azobis(4-cyanopentanoic acid), dimethyl 2,2'-azobis(2-methylpropionate), 2,2'-azobis[2-methyl-N-(2-hydroxyethyl)propionamide], 2,2 '-Azobis(N-butyl-2-methylpropane), 2,2'-azobis[2-(2-imidazolin-2-yl)propane] dihydrochloride, 2,2'-azobis[2-(2-imidazolin-2-yl)propane], 2,2'-azobis(2-methylpropanediamine) dihydrochloride, 2,2'-azobis[N-(2-carboxyethyl)-2-methylpropanediamine] tetrahydrate, 4,4-azobis(4-cyanopentanoic acid) polymer with α,ω-bis(3-aminopropyl)polydimethylsiloxane (VPS-1001, purchased from Wako Pure Chemical Industries, Ltd.), and 4,4'-azobis(4-cyanopentanoic acid) polyethylene glycol polymer (VPE-0201, purchased from Wako Pure Chemical Industries, Ltd.).

[0078] [] 4. Curing accelerator The compositions of the present invention may contain at least one curing accelerator, comprising 0 to 5% by weight, preferably 0.1 to 2.5% by weight, based on the weight of the composition. Non-limiting examples of usable curing accelerators that may be present in the composition alone or in combination include: (i) Aromaticamines of the following general formula: Wherein: R1′ is an aryl group that is substituted as appropriate, specifically a phenyl group that is substituted as appropriate with an alkyl group; R 2′ has the same meaning as R 1′ or, as appropriate, a substituted straight-chain or branched alkyl group; R 3′ is a straight-chain or branched alkyl group, which may be substituted, but contains at least one hydrogen atom at the α-position of nitrogen; and Any two of R1′ to R3′ can be combined to form a monocyclic or polycyclic ring structure, which may be a fused ring structure, and may subsequently be substituted; (ii) Compounds having the following general formula: Wherein: R 4′ is a phenyl group substituted with a C1-C4 alkyl group; and R 5′ is selected from hydrogen, alkyl, cycloalkyl, alkenyl, cycloalkenyl, aryl, alkoxy, aryloxy, carbonyl, amino, and the following groups: R 7′ is selected from alkyl groups containing 1 to 10 carbon atoms; (iii) sulfonylureas; or (iv) Hydropyridine.

[0079] Other specific non-limiting examples of curing accelerators include: saccharin; toluidine, such as N,N-diethyl-p-toluidine (DE-pT) and N,N-dimethyl-o-toluidine (DM-oT); acetylphenylhydrazine (APH); and maleic acid. Other exemplary curing accelerators include: sulfonamides and their oxygen and sulfur derivatives, such as those described in U.S. Patent No. 6,958,368 (Klemarczyk); phenylglycine and its derivatives; 1,4-aminobenzoyl compounds; phenylpyrazolone, sulfenimine derivatives, and sulfenamide derivatives, as disclosed in U.S. Patent No. 7,411,025 (Messana); trithiazazacyclopentadiene, as described in U.S. Patent No. 6,583,289 (McCardle); the reaction product of succinic anhydride and phenylhydrazine (SPH), which can be prepared according to U.S. Patent No. 6,835,782 (Morita); and compounds comprising -C(=O)-NH-NH- bonds linked to organic acid functional groups on the same molecule, as disclosed in U.S. Patent No. 6,835,762 (Klemarczyk).

[0080] 5. Solubilizer The compositions of the present invention may, as appropriate, contain a solubilizer. Such compositions may, for example, contain 0 to 10% by weight or 0 to 5% by weight of a solubilizer based on the weight of the composition. The solubilizer has the function of promoting the miscibility of electrolytes ii) within the adhesive composition: the solubilizer may or may not form part of the polymer matrix formed after the adhesive composition has cured, but it does indeed serve to promote ion transfer therein. Therefore, the solubilizer is preferably a polar compound and should ideally be a liquid at room temperature.

[0081] Suitable categories of solubilizers include: polyphosphazenes; polymethylene sulfides; polyoxyalkylene glycols; polyethyleneimine; polysiloxane surfactants, such as polyalkylsiloxanes and polyoxyalkylene-modified polydimethylsiloxanes, including (but not limited to) poly(C2 to C3)oxyalkylene-modified polydimethylsiloxanes; copolymers of functionalized polyalkylsiloxanes and epoxy resins, such as copolymers of polydimethylsiloxane (PDMS) and epoxy resins; polyols; and sugars. For completeness, fluorinated polysiloxane surfactants, such as fluorinated polysilanes, are intended to be included within the term polysiloxane surfactant.

[0082] Polyols and sugars, such as ethylene glycol, 1,3-propanediol, cyclohexanediol, hydroquinone, catechol, resorcinol, phloroglucinol, biphenyl pyroglucinol, hydroxyhydroquinone, hydroxymethylbenzene, hydroxymethylbenzene with three methyl or ethyl substituents bonded to the remaining carbon atoms of benzene, isosorbide, isomannitol, isoidide, glycerol, cyclohexane-1,2,4-triol, 1,3,5-cyclohexanetriol, pentane-1,2,3- Triol, hexane-1,3,5-triol, erythritol, 1,2,4,5-tetrahydroxybenzene, threitol, arabinol, xylitol, ribitol, mannitol, sorbitol, inositol, fructose, glucose, mannose, lactose, 1,1,1-tris(hydroxymethyl)propane, 1,1,1-tris(hydroxymethyl)ethane, di(trimethylolpropane), trimethylolpropane ethoxide, 2-hydroxymethyl-1,3-propanediol, pentaerythritol allyl ether, and pentaerythritol.

[0083] In polyoxyalkylene glycols, polyoxy(C2-C3)alkylene glycols having an average molecular weight (Mw) of 200 to 10,000 g / mol, for example 200 to 2,000 g / mol, are particularly preferred. For completeness, the term polyoxy(C2-C3)alkylene refers to a polyether group derived from ethylene oxide, propylene oxide, or both ethylene oxide and propylene oxide.

[0084] [] Additives and auxiliary ingredients The compositions obtained in this invention will generally further comprise adjuvants and additives that impart improved properties to the compositions. For example, such adjuvants and additives may impart one or more of the following: improved elasticity, improved elastic recovery, longer start-up time, faster curing time, and lower residual viscosity. Such adjuvants and additives include: toughening agents, conductive particles, non-conductive fillers, plasticizers, abrasion-resistant additives (including thermoplastic polyurethanes), stabilizers (including UV stabilizers), antioxidants, reactive diluents, driers, adhesion promoters, bactericides, flame retardants, rheology adjuvants, color pigments or color pastes, and / or, where applicable, also to a small extent, non-reactive diluents.

[0085] These adjuvants and additives may be used in the desired combination and proportions, provided that they do not adversely affect the properties and essential properties of the composition. Although there may be exceptions in some cases, these adjuvants and additives should not all exceed 30% by weight of the total composition and preferably should not exceed 20% by weight of the composition.

[0086] The presence of toughening agents in the compositions of the present invention can be advantageous for debonding of cured adhesives. Not to be limited to theory, these toughening agents promote phase separation within the cured adhesive under applied potential. Specifically, good debonding results have been obtained when the compositions of the present invention contain 0 to 20% by weight, for example 0.5 to 20% by weight or 0.5 to 15% by weight of at least one toughening agent selected from: core-shell elastomeric adducts dispersed in a matrix polymer and tough rubber, based on the weight of the composition.

[0087] The term "core-shell rubber" or CSR is used according to its standard meaning in this art, referring to a rubber particle core formed of a polymer comprising an elastic or rubbery polymer as the main component and a shell formed of a polymer grafted to the core. The shell partially or completely covers the surface of the rubber particle core during the grafting polymerization process. The core should constitute at least 50% by weight of the core-shell rubber particle.

[0088] The polymeric material of the core should have a glass transition temperature (Tg) not greater than 0°C and preferably -20°C or lower, more preferably -40°C or lower, and even more preferably -60°C or lower. The polymer of the shell is a non-elastic, thermoplastic, or thermosetting polymer with a glass transition temperature (Tg) greater than room temperature, preferably greater than 30°C, and more preferably greater than 50°C.

[0089] Without limiting the invention, the core may comprise: diene homopolymers, such as butadiene or isoprene homopolymers; diene copolymers, such as copolymers of butadiene or isoprene with one or more olefinic unsaturated monomers (such as vinyl aromatic monomers, (meth)acrylonitrile, or (meth)acrylate); polymers based on (meth)acrylate monomers, such as polybutyl acrylate; and polysiloxane elastomers, such as polydimethylsiloxane and cross-linked polydimethylsiloxane.

[0090] Similarly, without limiting the invention, the shell may comprise a polymer or copolymer selected from one or more of the following monomers: (meth)acrylates, such as methyl methacrylate; vinyl aromatic monomers, such as styrene; vinyl cyanides, such as acrylonitrile; unsaturated acids and anhydrides, such as acrylic acid; and (meth)acrylamide. The polymer or copolymer used in the shell may have acid groups cross-linked through metal carboxylates, specifically through salt ions forming divalent metal cations. The shell polymer or copolymer may also be covalently cross-linked by monomers having two or more double bonds per molecule.

[0091] Preferably, any included core-shell rubber particles have an average particle size (d50) of 10 nm to 300 nm, for example 50 nm to 250 nm: this particle size refers to the diameter or maximum size of the particle in the particle distribution and is measured by dynamic light scattering. For completeness, this application does not exclude the presence of two or more types of core-shell rubber (CSR) particles with different particle size distributions in the composition to provide a balance of key properties of the resulting cured product, including shear strength, peel strength, and resin fracture toughness.

[0092] The core-shell rubber can be selected from commercially available products, examples of which include: Paraaloid EXL 2650A, EXL 2655 and EXL2691 A from Dow Chemical; Clearstrength® XT100 from Arkema Inc.; Kane Ace® MX series from Kaneka, and specifically MX 120, MX 125, MX 130, MX 136, MX 551 and MX553; and METABLEN SX-006 from Mitsubishi Rayon.

[0093] As specified above, the compositions of the present invention comprise 0 to 20% by weight, for example, 0.5 to 10% by weight, of a filler. This filler may be used independently of or in combination with the toughening agents mentioned above. The use of conductive and / or non-conductive fillers is contemplated; however, in one embodiment, the filler contained in the composition consists of or is substantially composed of non-conductive particulate fillers.

[0094] As specified, the compositions of the present invention may therefore contain conductive particulate fillers. The composition may, for example, contain 0 to 10% by weight or 0.5 to 5% by weight of conductive particles based on the weight of the composition.

[0095] Broadly speaking, there is no particular intention to limit the shape of the particles used as conductive fillers: needle-shaped, spherical, elliptical, cylindrical, bead-like, cubic, or flake-like particles can be used alone or in combination. Furthermore, it is conceivable to use aggregates of more than one particle type. Similarly, there is no particular intention to limit the size of the particles used as conductive fillers. However, these conductive fillers will conventionally have an average volume particle size of 0.1 to 1500 μm, for example, 1 to 1250 μm, as measured by laser diffraction / scattering methods.

[0096] Exemplary conductive particulate fillers include (but are not limited to): silver, copper, gold, palladium, platinum, nickel, nickel coated with gold or silver, carbon black, carbon fiber, graphite, aluminum, indium tin oxide, silver-coated copper, silver-coated aluminum, metal-coated glass spheres, metal-coated fillers, metal-coated polymers, silver-coated fibers, silver-coated spheres, antimony-doped tin oxide, conductive nanospheres, nano-silver, nano-aluminum, nano-copper, nano-nickel, carbon nanotubes, and mixtures thereof. The use of particulate silver and / or carbon black as conductive fillers is preferred.

[0097] The compositions of the present invention may further comprise non-conductive particulate fillers. The composition may, for example, contain 0 to 10% by weight or 0.5 to 10% by weight of non-conductive particles based on the weight of the composition.

[0098] Broadly speaking, there is no particular intention to limit the shape of the particles used as non-conductive fillers: needle-shaped, spherical, elliptical, cylindrical, bead-like, cubic, or flake-like particles can be used alone or in combination. Furthermore, it is conceivable to use aggregates of more than one particle type. Similarly, there is no particular intention to limit the size of the particles used as non-conductive fillers. However, such non-conductive fillers will conventionally have an average volume particle size of 0.1 to 1500 μm, for example, 1 to 1250 μm, as measured by laser diffraction / scattering methods.

[0099] Exemplary non-conductive fillers include (but are not limited to) calcium carbonate, calcium oxide, calcium hydroxide (lime powder), fuming silica, amorphous silica, precipitated and / or pyrogenic silicic acid, zeolite, bentonite, wollastonite, magnesium carbonate, diatomaceous earth, barium sulfate, alumina, clay, talc, titanium dioxide, iron oxide, zinc oxide, sand, quartz, flint, mica, glass beads, glass powder, and other ground minerals. Organic fillers may also be used, specifically wood fiber, wood flour, sawdust, cellulose, cotton, pulp, wood chips, chopped straw, bran, ground walnut shells, and other chopped fibers. Short fibers, such as glass fiber, glass filament, polyacrylonitrile, carbon fiber, Kevlar fiber, or polyethylene fiber, may also be added.

[0100] Pyrogenic and / or precipitating silica advantageously has a BET surface area of ​​10 to 90 m² / g. When used, it does not cause any additional increase in viscosity of the compositions according to the invention, but does help to strengthen the cured compositions.

[0101] Similarly, it is conceivable to use pyrogenic and / or precipitated silica with a higher BET surface area of ​​advantageously 100 to 250 m² / g as a filler: because of the larger BET surface area, the effect of enhancing the cured composition is achieved by utilizing a smaller proportion of silica by weight.

[0102] It is also suitable as a non-conductive filler for hollow spheres with mineral or plastic shells. These can be, for example, hollow glass spheres commercially available under the trademark Glass Bubbles®. Plastic-based hollow spheres, such as Expancel® or Dualite® and described in EP 0 520 426 B1, can be used: they are composed of inorganic or organic materials and each has a diameter of 1 mm or less, preferably 500 µm or less.

[0103] Non-conductive fillers that impart thixotropic properties to the composition are preferred for many applications: such fillers are also described as rheology adjuvants, for example, hydrogenated castor oil, fatty acid amides, or expandable plastics (such as PVC).

[0104] The desired viscosity of the resulting curable composition determines the amount of filler used. Regarding the latter consideration, the total amount of filler present in the composition – both conductive and non-conductive – should not prevent the composition from being easily applied to a substrate by the chosen application method. For example, a curable composition intended to be extruded from a suitable dispensing device (such as a tube) should have a viscosity of 1,000 to 150,000, preferably 10,000 to 100,000 mPas.

[0105] For the purposes of this invention, "plasticizer" is a substance that reduces the viscosity of a composition and thus promotes its processability. The plasticizer herein may constitute at most 10% by weight or at most 5% by weight based on the total weight of the composition, and is preferably selected from the group consisting of: diaminocarbamates; ethers of monofunctional linear or branched C4-C16 alcohols, such as Cetiol OE (available from Cognis Deutschland GmbH, Düsseldorf); esters of rosin acid, butyric acid, thiobutyric acid, acetic acid, propionate, and citric acid; esters based on nitrocellulose and polyvinyl acetate; fatty acid esters; dicarboxylic acid esters; esters carrying OH- groups or epoxidized fatty acids; glycolates; benzoates; phosphate esters; sulfonates; benzotriesters; polyether plasticizers, such as terminally capped polyethylene glycol or polypropylene glycol; polystyrene; hydrocarbon plasticizers; chlorinated paraffins; and mixtures thereof. It should be noted that phthalates can be used as plasticizers in principle, but these are not preferred due to their potential toxicity.

[0106] For the purposes of this invention, "stabilizer" should be understood as an antioxidant, heat stabilizer, or hydrolytic stabilizer. Stabilizers as used herein may constitute at most 10% by weight or at most 5% by weight based on the total weight of the composition. Standard commercial examples of stabilizers suitable for use herein include: sterically hindered phenols, thioethers, benzotriazoles, benzo[a]ones, benzoates, cyanoacrylates, acrylates, hindered amine light stabilizers (HALS) type amines, phosphorus, sulfur, and mixtures thereof.

[0107] It should be noted that compounds with metal chelating properties can be used in the compositions of the present invention to help enhance the adhesion of the cured adhesive to the substrate surface. Additionally, acetylacetic acid-functionalized modified resins sold by King Industries under the trademark K-FLEX XM-B301 are also suitable as adhesion promoters.

[0108] To further enhance shelf life, it is generally recommended to further stabilize the compositions of the present invention by using a desiccant to address moisture penetration. Occasionally, there is also a need, for specific applications, to reduce the viscosity of the adhesive compositions according to the present invention by using a reactive diluent. The total amount of reactive diluent present is typically 0 to 10% by weight, for example, 0 to 5% by weight, based on the total weight of the composition.

[0109] While this may help to mitigate viscosity, the presence of solvents and non-reactive diluents in the compositions of the present invention is not excluded. For example, but only for illustrative purposes, such compositions may contain one or more of the following: xylene, 2-methoxyethanol, dimethoxyethanol, 2-ethoxyethanol, 2-propoxyethanol, 2-isopropoxyethanol, 2-butoxyethanol, 2-phenoxyethanol, 2-benzyloxyethanol, benzyl alcohol, ethylene glycol, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, ethylene glycol diphenyl ether, diethylene glycol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol mono-n-butyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol di-n-butyl ether, propylene glycol butyl ether, propylene glycol Phenyl ether, dipropylene glycol, dipropylene glycol monomethyl ether, dipropylene glycol dimethyl ether, dipropylene glycol di-n-butyl ether, N-methylpyrrolidone, diphenylmethane, diisopropylnaphthalene, petroleum ether solvents (such as Solvesso® products (purchased from Exxon)), alkylphenols (such as tert-butylphenol, nonylphenol, dodecylphenol and 8,11,14-pentadecanetinylphenol), styrene-modified phenol, bisphenol, aromatic resins (especially those containing phenolic groups, such as ethoxylated or propoxylated phenol), adipate esters, sebate esters, phthalate esters, benzoate esters, organophosphonic acids or sulfonates, and sulfonamides.

[0110] In addition to the above, preferably, all of these non-reactive diluents constitute less than 10% by weight, specifically less than 5% by weight or less than 2% by weight, based on the total weight of the composition.

[0111] [] Methods and Applications To form the defined curable composition, the components are brought together and mixed. Importantly, this mixing ensures that the electrolyte (non-polymerizable compound (above 2)) is uniformly distributed within the adhesive composition: this thorough and effective mixing determines the uniform distribution of charged substances within the polymer matrix obtained after curing and thus provides sufficient ionic conductivity to support electrochemical reactions at the interface with the conductive substrate.

[0112] As is known in this art, to form a single-component (1K) curable composition, the elements of the composition are brought together and uniformly mixed under conditions that inhibit or prevent the reaction of reactive components: these conditions are easily understood by a skilled technician. Therefore, it is generally preferred that the curable elements are not mixed by hand, but rather by machine (e.g., a static or dynamic mixer) in predetermined amounts under anhydrous conditions and without deliberate light exposure.

[0113] According to the most extensive process configuration of the present invention, the above-described composition is applied to the material layer(e.g.) and then cured in situ. Prior to applying the composition, it is generally recommended to pretreat the relevant surfaces to remove foreign matter, and if applicable, this step can promote the subsequent adhesion of the composition to them. Such treatments are known in the art and can be performed in a single-stage or multi-stage manner, for example, using one or more of the following: etching treatment using an acid suitable for the substrate and, where appropriate, an oxidizing agent; acoustic treatment; plasma treatment, including chemical plasma treatment, corona treatment, atmospheric plasma treatment, and flame plasma treatment; immersion in an aqueous alkaline degreasing bath; treatment with an aqueous cleaning emulsion; treatment with a cleaning solvent, such as acetone, carbon tetrachloride, or trichloroethylene; and rinsing with water, preferably deionized water or demineralized water. In the case of using an aqueous alkaline degreasing bath, any of the degreasing agents remaining on the surface should be removed by rinsing the substrate surface with deionized water or demineralized water.

[0114] In some embodiments, adhesion of the coating composition of the present invention to a preferably pretreated substrate can be promoted by applying a primer to it. Indeed, the primer composition may be necessary to ensure effective fixation and / or curing time of the adhesive composition on an inactive substrate. While a skilled craftsman can select a suitable primer, illustrative references for selecting a primer include (but are not limited to): U.S. Patent Nos. 3,855,040, 4,731,146, 4,990,281, 5,811,473, GB 2502554, and 6,852,193.

[0115] The composition is then applied to a preferably pretreated, or if appropriate, primer-coated surface of a substrate by conventional coating methods such as brushing, rolling, scraping, printing, and spraying, including (but not limited to) air atomization spraying, air-assisted spraying, airless spraying, and high-volume low-pressure spraying.

[0116] As specified above, the present invention provides an adhesive structure comprising: a first material layer having a conductive surface; and a second material layer having a conductive surface, wherein a curable electrochemically debonding adhesive composition as defined above and in the appended claims is disposed between the first material layer and the second material layer. To produce this structure, an adhesive composition may be applied to at least one inner surface of the first and / or second material layers, and then the two layers may be brought into contact under applied pressure, thereby inserting an electrochemically debonding adhesive composition between the two layers.

[0117] It is recommended that the composition to be applied to the surface have a wet film thickness of 10 to 500 μm. Applying thinner layers within this range is more economical and offers the possibility of reducing harmful thick cured areas. However, strict controls must be implemented when applying thinner coatings or layers to avoid the formation of discontinuous cured films.

[0118] Given that the composition contains a thermal initiator, it must be cured by raising the temperature of the composition above the activation temperature of the initiator. The activation temperature, of course, depends on the specific compound present, but this temperature needs to ensure the desired curing rate and, in some cases, can be determined by a skilled technician using simple preliminary tests (if necessary). Without limiting the invention, complete curing of the applied curable composition should generally occur within a temperature range of 20°C to 150°C, preferably 20°C to 120°C, and specifically 45°C to 100°C. Where applicable, conventional methods (including microwave induction) can be used to raise the temperature of the curable composition above the mixing temperature and / or application temperature.

[0119] As shown in Figure 1a, an adhesive structure is provided in which a layer of cured adhesive (10) is disposed between two conductive substrates (11). A layer of non-conductive material (12) may be disposed on the conductive substrate (11) to form a more complex adhesive structure as shown in Figure 1b. Each layer of the conductive substrate (11) is in electrical contact with a power source (13), which may be a battery or a direct current (DC) AC drive. The positive and negative terminals of the power source (13) are shown in a fixed position, but a skilled technician will naturally know the polarity of the reversible system.

[0120] Two conductive substrates (11) are shown in the form of layers, which may be particularly composed of: metal films, metal meshes or grids, deposited metal particles, resin materials or conductive oxide layers that conduct electricity by means of conductive elements deposited therein. As exemplary conductive elements, silver wires, single-walled carbon nanotubes and multi-walled carbon nanotubes may be mentioned. As exemplary conductive oxides, indium oxide, such as indium tin oxide (ITO); zinc oxide; antimony tin oxide; cadmium stannate and zinc stannate may be mentioned. In addition to the selection of conductive materials, those skilled in the art will know that when the conductive substrates (11) are in the form of meshes or grids that provide limited contact with the layers of cured adhesive (10), the efficiency of the debonding operation can be reduced.

[0121] When a voltage is applied between the conductive substrates (11), current is supplied to the adhesive composition (10) disposed between them. This induces an electrochemical reaction at the interface between the substrates (11) and the adhesive composition, which should be understood as oxidation at the positively charged or anodic interface and reduction at the negatively charged or cathode interface. It is believed that these reactions weaken the adhesion between the substrates, allowing the removable adhesive composition to be easily removed from the substrates.

[0122] As shown in Figures 2a and 2b, debonding occurs at the positive interface, where the interface between the adhesive composition (10) and the conductive surface (11) is in positive electrical contact. By reversing the current direction before separating the substrates, adhesive bonding can be weakened at the interface between the two substrates.

[0123] However, it should be noted that the composition of the adhesive layer (10) can be adjusted so that debonding occurs at the positive or negative interface, or simultaneously at both. For some embodiments, applying a voltage across both surfaces to form an anodic and a cathode interface will cause debonding to occur simultaneously at both the anodic and cathode adhesive / substrate interfaces. In alternative embodiments, if the composition is not responsive to DC at both interfaces, opposite polarities can be used to debond both substrate / adhesive interfaces simultaneously. Current can be applied using any suitable waveform, provided sufficient total time is allowed for debonding to occur at each polarity. In this regard, sinusoidal, rectangular, and triangular waveforms are suitable and can be applied from a controllable voltage or controllable current source.

[0124] Without intending to limit the invention, it is considered that the debonding operation can be effectively performed under at least one and preferably both of the following conditions: a) an applied voltage of 0.5 to 200 V, for example 10 to 100 V; and b) an applied voltage lasting from 1 second to 120 minutes, for example 1 second to 60 minutes. In cases where the release of the self-curing adhesive on the conductive substrate is facilitated by applied force – for example, by a weight or spring – only a few seconds of applied potential may be required.

[0125] The following examples illustrate the invention and are not intended to limit the scope of the invention in any way.

[0126] [, , ] Example The following materials were used in the example: HEMA (Hydroxyethyl methacrylate monomer) Monomer blend 1: Polyurethane methacrylate (PUMA, Mw 2000 to 5000 g / mol) and isobornyl methacrylate Saccharin accelerator, purchased from Sigma Aldrich Acetylphenylhydrazine accelerator, purchased from Sigma Aldrich Cumene peroxide curing agent, purchased from Sigma Aldrich 1-Ethyl-3-methylimidazolium methanesulfonate: Purchased from TCI America Inc. 1-Ethyl-3-methylimidazolium chloride: Purchased from TCI America Inc. Aerosil 200: Hydrophilic fuming silicon dioxide, purchased from Evonik Industries. Clearstrength® XT100: Core-shell toughening agent (methyl methacrylate-butadiene-styrene, MBS), purchased from Arkema Inc. Estane 5715: Polyester thermoplastic polyurethane (TPU), purchased from Lubrizol Premix 18: Tetrasodium EDTA solution (9% by weight). Premix 31: Etiphosphate solution (5.5% by weight).

[0127] [] Examples 1 to 3 The compositions were prepared according to Table 1 below. The given components were mixed in a speed mixer (1200 rpm; 1 minute) to ensure the formation of a homogeneous mixture. [surface] [1] [] Element Example 1 (by weight %) Example 2 (by weight %) Example 3 (by weight %) HEMA 40.0 43.3 38.4 Monomer Blend 1 38.9 41.9 37.0 saccharin 1.3 1.2 0.9 Cumene hydroperoxide 1.0 1.0 0.7 Acetylphenylhydrazine 0.7 0.7 0.5 Premix 18 body 0.1 Premix 31 body 0.1 EMIM MS 10.7 10.0 10.2 Aerosil 200 1.8 1.8 1.8 Estane 5715 5.8 Clearstrength XT100 10.2 total 100.0 100.0 100.0

[0128] The test substrate was aluminum (AA6016) with a surface cleaned with ethyl acetate. The substrate was provided at a thickness of 0.1 inches and cut into six 2.5 cm x 10 cm (1" x 4") samples for tensile testing. The tensile lap shear (TLS) test was performed at room temperature based on the ASTM D3163-01 standard test method for determining the strength of bonded rigid plastic lap-shear joints under tensile load shear. The overlap area of ​​each specified substrate was 2.5 cm x 1.0 cm (1" x 0.4"), with a bond thickness of 0.15 cm (60 mils).

[0129] The applied adhesive composition was cured in the overlapping area by applying a temperature of 100°C for 30 minutes. The bonded structure was then stored at 25°C and 20% relative humidity for 24 hours, after which tensile testing was initiated.

[0130] For each bonded structure, the tensile lap shear strength was studied both before and after the 24-hour storage period, prior to the application of a constant potential of 30 V across the adhesive layer for 20 minutes. The average results are recorded in Table 2 below. [surface] [2] [] Example Initial bond strength (MPa) Bond strength (MPa) after 30 V for 20 minutes 1 5.3 ± 0.8 2.7 ± 0.5 2 8.2 ± 2.2 2.8 ± 0.9 3 4.3 ± 1.4 1.0 ± 0.7

[0131] Based on the above description and examples, it is obvious that those familiar with this technology can make equivalent modifications without departing from the scope of the patent application.

[0132] 10: Adhesive composition 11: Conductive substrate 12: Non-conductive materials 13: Power supply

Claims

1. A curable and electrochemically debondable one-component (1K) adhesive composition comprising, based on the weight of the composition: 60 to 90 wt% of i) at least one olefinic unsaturated nonionic monomer, wherein (meth)acrylate monomers constitute at least 60 moles of the total mole amount of the olefinic unsaturated nonionic monomers, and wherein the (meth)acrylate monomers include C1-C6 hydroxyalkyl esters of (meth)acrylic acid; 1 to 20 wt% of ii) a nonpolymerizable electrolyte; 0.1 to 10 wt% of iii) at least one radical-generating thermal initiator; 0 to 20 wt% of iv) a filler; and 0 to 20 wt% of v) a toughening agent; The non-polymerizable electrolyte is selected from the group consisting of: 1-ethyl-3-methyl-1H-imidazol-3-onium methanesulfonate, 1-ethyl-3-methyl-1H-imidazol-3-onium methylsulfate, 2-(2-fluoroanilino)pyridine-1-hexyl-3-methylimidazolium, 1-hexyl-3-methylimidazolium amide, 2-(2-fluoroanilino)pyridine-1-butyl-1-methyl-pyrrolidone, 1-butyl-1-methyl-pyrrolidone amide. Amines, 2-(2-fluoroaniline)-pyridinetrihexyl(tetradecyl)phosphonium, cyclohexyltrimethylammonium bis(trifluoromethanesulfonyl)imidine, di(2-hydroxyethyl)ammonium trifluoroacetate, N,N-dimethyl(2-hydroxyethyl)ammonium octanoate, methyltrioctylammonium bis(trifluoromethanesulfonyl)imidine, N-ethyl-NNNN-tetramethylguanidine trifluoromethanesulfonate, guanidine trifluoromethanesulfonate, 1-butyl-4-methylpyridinium bromide, 1-butyl-3-methylpyridinium tetrafluoroborate 1-Butyl-3-hydroxymethylpyridinium ethyl sulfate, 1-Butyl-methylpyrrolidinium trifluorophosphate (pentafluoroethyl)trifluorophosphate, 3-methylimidazolium ethyl sulfate, 1-Ethyl-3-methylimidazolium chloride, 1-Ethyl-3-methylimidazolium bromide, 1-Butyl-3-methylimidazolium chloride, 1-Hexyl-3-methylimidazolium chloride, 1-Octyl-3-methylimidazolium chloride, 1-Propyl-3-methylimidazolium iodide, 1-Butyl-3-tetrafluoroboronic acid 1-Methylimidazolium, 1-ethyl-3-methylimidazolium trifluoromethanesulfonate, 1-butyl-3-methylimidazolium trifluoromethanesulfonate, 1-butyl-3-methylimidazolium hexafluorophosphate, 1-butyl-2,3-dimethylimidazolium tetrafluoroborate, 1-butyl-2,3-dimethylimidazolium hexafluorophosphate, 1-butylimidazolium, 1-methylimidazolium tetrafluoroborate, tetrabutylphosphonium trifluorophosphate (pentafluoroethyl)trifluorophosphate, trihexyl(tetradecyl)phosphonium tetrafluoroborate, and mixtures thereof.

2. The curable and electrochemically debondable one-component (1K) adhesive composition of claim 1, wherein the nonpolymerizable electrolyte comprises 1-butyl-1-methylpyrrolidone bis(trifluoromethylsulfonyl)imidinium.

3. The curable and electrochemically debondable one-component (1K) adhesive composition of claim 1, the composition comprising, based on the weight of the composition: 70 to 90 wt% of i) the at least one olefinic unsaturated nonionic monomer; 1 to 20 wt% of ii) the nonpolymerizable electrolyte; 0.1 to 5 wt% of iii) the at least one radical-generating thermal initiator; 0.5 to 20 wt% of iv) the filler; and 0.5 to 20 wt% of v) the toughening agent.

4. The curable and electrochemically debondable one-component (1K) adhesive composition of claim 1, wherein the (meth)acrylate monomer constitutes at least 75 moles of the total mole amount of the olefinic unsaturated nonionic monomer.

5. The curable and electrochemically debondable one-component (1K) adhesive composition of claim 1, wherein the (meth)acrylate monomers comprise one or more oligomers selected from the group consisting of urethane (meth)acrylates, polyester (meth)acrylates and polyether (meth)acrylates.

6. The curable and electrochemically debondable one-component (1K) adhesive composition of claim 5, comprising at least one urethane (meth)acrylate oligomer.

7. The curable and electrochemically debondable one-component (1K) adhesive composition of claim 1, wherein the electrolyte is selected from the group consisting of 1-ethyl-3-methyl-1H-imidazol-3-onium methanesulfonic acid, 1-ethyl-3-methylimidazolium trifluoromethanesulfonic acid, 1-ethyl-3-methyl-1H-imidazol-3-onium methylsulfate, and mixtures thereof.

8. A curable and electrochemically debondable one-component (1K) adhesive composition as claimed in any of claims 1 to 7, wherein the at least one free radical generating thermal initiator is selected from the group consisting of: cumene hydroperoxide (CHP), p-menthane hydroperoxide, tert-butyl hydroperoxide (TBH), tert-butyl perbenzoate, tert-butyl perpentanoate, di-tert-butyl peroxide, tert-butyl peracetate, tert-butyl peroxy-2-hexanoate, tert-pentyl hydroperoxide, and hydrogen... 1,2,3,4-Tetramethylbutyl peroxide, benzoyl peroxide, 1,3-bis(tert-butylperoxyisopropyl)benzene, diacetyl peroxide, butyl 4,4-bis(tert-butylperoxy)valerate, p-chlorobenzoyl peroxide, tert-butylisopropylbenzene peroxide, diisopropylbenzene peroxide, 2,5-dimethyl-2,5-ditert-butylperoxyhexane, 2,5-dimethyl-2,5-ditert-butyl-peroxyhex-3-yne, and 4-methyl-2,2-ditert-butylperoxypentane.

9. A curable and electrochemically debonding one-component (1K) adhesive composition of any one of claims 1 to 7, further comprising at least one curing accelerator in a weight percentage of up to 5% based on the weight of the composition.

10. A curable and electrochemically debondable one-component (1K) adhesive composition of any one of claims 1 to 7, further comprising 0.5 to 10% by weight of non-conductive particulate filler based on the weight of the composition.

11. A curable and electrochemically debonding one-component (1K) adhesive composition of any one of claims 1 to 7, comprising 0.5 to 15% by weight of the toughening agent.

12. An adhesive structure comprising a first material layer having a conductive surface; a second material layer having a conductive surface; wherein a cured electrochemically debondable one-component (1K) adhesive composition as defined in any one of claims 1 to 11 is disposed between the first material layer and the second material layer.

13. A method for debonding an adhesive structure as claimed in claim 12, the method comprising the steps of: 1) applying a voltage across two surfaces to form an anode interface and a cathode interface; and 2) debonding the surfaces, wherein the voltage applied in step 1 is from 0.5 to 200 V and is applied for from 1 second to 60 minutes.

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