CN115867586A

CN115867586A - Electrochemically debondable adhesive compositions

Info

Publication number: CN115867586A
Application number: CN202180043616.5A
Authority: CN
Inventors: K·W·周; D·佩拉尔克雷斯波; C·安杜伊克斯坎托; A·M·迪亚斯罗维拉; A·贝尔梅斯列多; V·佩雷斯帕迪利亚
Original assignee: Henkel AG and Co KGaA
Current assignee: Henkel AG and Co KGaA
Priority date: 2020-06-22
Filing date: 2021-05-31
Publication date: 2023-03-28
Also published as: KR20230027053A; JP2023530767A; TW202210598A; WO2021259594A1

Abstract

The present invention relates to a curable and electrochemically debondable adhesive composition comprising, based on the weight of the composition: from 40 to 99 weight percent of a) at least one ethylenically unsaturated nonionic monomer; 0.9 to 50 wt.% of b) at least one polymerizable compoundA sub-compound, wherein the polymerizable ionic compound comprises: b1 At least one compound according to formula IV; and/or b 2) at least one compound according to formula V; and from 0.1 to 10% by weight of c) at least one free-radical initiator.

Description

Electrochemically debondable adhesive compositions

Technical Field

The present invention relates to curable adhesive compositions that can be debonded from the particular substrate to which they are applied. More particularly, the present invention relates to curable and electrochemically debondable adhesive compositions comprising a polymerizable electrolyte.

Background

Adhesive bonds and polymer coatings are commonly used in the assembly and finishing of finished goods. They are used in place of mechanical fasteners (e.g., screws, bolts, and rivets) to provide bonding at reduced machine cost and greater serviceability during manufacturing. Adhesive bonding evenly distributes stress, reduces the likelihood of fatigue, and seals the joint from corrosive substances.

While adhesive bonding provides many advantages over mechanical fasteners, in practical applications (e.g., in recycling of the primary material being adhered) it tends to be difficult to disassemble the adhesively bonded article if desired. Removal of the adhesive by mechanical means (e.g., by grit blasting or by wire brushing) is generally precluded, in part, because the adhesive is disposed between the substrates and is therefore difficult to access or to grind without damaging the substrate surfaces. Disassembly by application of chemicals and/or high temperatures, as disclosed in U.S. patent No. 4,171,240 (Wong) and U.S. patent No. 4,729,797 (Linde et al), can be effective, but can be time consuming and complex to perform; furthermore, the aggressive chemicals and/or harsh conditions required can damage the separated substrates, making them unsuitable for subsequent use.

In view of these problems, some authors have attempted to develop electrochemically debondable adhesive compositions in which an electrical current is acted upon by the cured composition to break the bond at the interface of the adhesive and the substrate.

US 2007/0269659 (Gilbert) describes an adhesive composition debondable at two interfaces, the composition: (i) comprises a polymer and an electrolyte; (ii) facilitating the joining of two surfaces; and (iii) is responsive to a voltage applied across the two surfaces to form an anode interface and a cathode interface, thereby debonding from both the anode surface and the cathode surface.

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 faradaic reaction (faradaic reaction) at a bond formed between the composition and an electrically conductive surface and to allow debonding of the composition from the surface.

WO2007/142600 (Stora Enso AB) describes an electrochemically weakable adhesive composition providing adhesive bonding to an electrically conductive surface and sufficient ionic conductivity to achieve weakening of said adhesive bonding upon application of a voltage across the adhesive composition, wherein said composition comprises an effective amount of at least one ionic compound to impart said ionic conductivity, and wherein the melting point of said ionic compound is not higher than 120 ℃.

EP 3363875A (Nitto Denko Corporation) provides an electrically peelable adhesive composition that forms an adhesive layer that has high adhesiveness and can be easily peeled off when a voltage is applied for a short time. The electrically releasable adhesive composition of the invention comprises a polymer and from 0.5 to 30 wt%, based on the weight of the polymer, of an ionic liquid, wherein the anion of the ionic liquid is a bis (fluorosulfonyl) imide anion.

WO2013/135677 (Henkel AG & co. Kgaa) describes a hot melt adhesive comprising: 20 to 90 wt.% of at least one polyamide with a molecular weight (Mw) of 10000 to 250000 g/mol; 1 to 25 wt% of at least one organic or inorganic salt; and 0 to 60 wt% of further additives, wherein the softening point of the binder is 100 to 220 ℃.

WO2016/135341 (Henkel AG & co. Kgaa) describes a reactive hot melt adhesive composition which at least partially loses its adhesive strength upon application of a voltage and thus allows debonding of substrates which have been bonded using said adhesive. More specifically, the reactive hot melt adhesive composition comprises: a) At least one isocyanate functional polyurethane polymer; and b) at least one organic or inorganic salt.

WO2017/133864 (Henkel AG & 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 one or more non-conductive substrates with a conductive ink; b) Applying an electrically debondable 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 debondable hot melt adhesive composition is sandwiched between the two substrates; d) Forming an adhesive bond between two substrates to provide a bonded substrate; and e) applying a voltage to the bonded substrate, whereby the adhesive force on at least one interface between the electrically debondable hot melt adhesive composition and the substrate surface is substantially weakened.

Where an ionic liquid or electrolyte has been included in the adhesive composition, compatibility of the electrolyte with the polymer matrix may be difficult to achieve. In the known art, leakage and phase separation of electrolyte from the cured polymer matrix has been recognized as a disadvantage in the application of electrically debondable adhesives.

There remains a need in the art to provide an adhesive composition that can be conveniently applied to the surfaces of substrates to be bonded, that can provide effective bonding within a composite structure containing the substrates after it has been cured, but that can be effectively debonded from those substrates by the easy application of an electrical potential across the cured adhesive. Furthermore, the cured adhesive should provide a stable polymer matrix from which leakage of components is minimized and within which no phase separation occurs.

Disclosure of Invention

According to a first aspect of the present invention there is provided a curable and electrochemically debondable adhesive composition comprising, based on the weight of the composition:

from 40 to 99% by weight, preferably from 45 to 90% by weight, of a) at least one ethylenically unsaturated nonionic monomer;

0.9 to 50 wt%, preferably 5 to 30 wt%, of b) at least one polymerizable ionic compound, wherein the polymerizable ionic compound comprises:

b1 At least one compound according to formula IV:

and/or

b2 At least one compound according to formula V):

/>

wherein: r ⁷ Selected from: c ₁ -C ₃₀ An alkyl group; c ₂ -C ₈ An alkenyl group; c ₁ -C ₃₀ A heteroalkyl group; c _3- C ₃₀ A cycloalkyl group; c ₆ -C ₁₈ An aryl group; c ₁ -C ₉ A heteroaryl group; c _7- C ₁₈ An alkylaryl group; c _2- C ₅ A heterocycloalkyl group; or-R ^a -C(＝O)-R ^b Wherein R is ^a Is C ₁ -C ₆ Alkylene, and R ^b Is C ₁ -C ₆ An alkyl group;

each R ⁸ Independently selected from H, C ₁ -C ₁₈ Alkyl radical, C ₁ -C ₁₈ Heteroalkyl group, C ₃ -C ₁₈ Cycloalkyl radical, C ₆ -C ₁₈ Aryl radical, C ₁ -C ₉ Heteroaryl group, C _7- C ₁₈ Alkylaryl, or C ₂ -C ₅ A heterocycloalkyl group;

R ⁹ is H or C ₁ -C ₄ An alkyl group;

each R ¹⁰ Independently selected from: c ₁ -C ₃₀ An alkyl group; c ₁ -C ₃₀ A heteroalkyl group; c _3- C ₃₀ A cycloalkyl group; c ₆ -C ₁₈ An aryl group; c ₁ -C ₉ A heteroaryl group; c _7- C ₁₈ An alkylaryl group; c _2- C ₅ A heterocycloalkyl group; or-R ^a -C(＝O)-R ^b Wherein R is ^a Is C ₁ -C ₆ Alkylene, and R ^b Is C ₁ -C ₆ An alkyl group;

a is a non-polymerizable anion;

t is an ethylenically unsaturated anion;

d and m are each integers having a value of at least 1;

e and n have values such that the compound is electrically neutral; and is

Is a covalent bond, C ₁ -C ₂ Alkylene radical, -CH ₂ OC(＝O)-、-CH ₂ CH ₂ OC (= O) -, p-benzyl, or p-tolyl; and

0.1 to 10 wt.%, preferably 0.1 to 5 wt.%, c) of at least one free-radical initiator.

The adhesive composition may be formulated as a one-part (1K) composition, a two-part (2K) composition, or a multi-part composition. Preference may be given to the moiety b) consisting of said compound according to moiety b 1) and/or moiety b 2).

In an embodiment of the composition, part a) thereof comprises 40 to 95 wt. -%, preferably 45 to 90 wt. -%, based on the weight of the composition, of a 1) at least one (meth) acrylate monomer represented by formula I:

H ₂ C＝CGCO ₂ R ¹ (I)

wherein: g is hydrogen, halogen or C ₁ -C ₄ An alkyl group; and is provided with

R ¹ Is selected from C ₁ -C ₃₀ Alkyl radical, C ₂ -C ₃₀ Heteroalkyl group, C ₃ -C ₃₀ Cycloalkyl radical, C ₂ -C ₈ Heterocycloalkyl radical, C ₂ -C ₂₀ Alkenyl and C ₂ -C ₁₂ Alkynyl.

Part a) of the composition may also be characterized by comprising, based on the weight of the composition, from 0 to 30 wt%, e.g., from 0 to 15 wt%, of a 2) at least one (meth) acrylate monomer represented by formula II:

H ₂ C＝CQCO ₂ R ² (II)

wherein: q may be hydrogen, halogen or C ₁ -C ₄ An alkyl group; and is

R ² May be selected from C ₆ -C ₁₈ Aryl radical, C ₁ -C ₉ Heteroaryl group, C ₇ -C ₁₈ Alkylaryl and C ₇ -C ₁₈ An aralkyl group.

In another embodiment of the composition, which is not intended to be mutually exclusive to those embodiments given above, part a) thereof comprises from 0 to 50 wt%, preferably from 5 to 25 wt%, based on the weight of the composition, of a 3) of at least one (meth) acrylate functionalized oligomer.

As regards electrolyte b) of the curable and electrochemically debondable composition, both the ionic compounds according to formula IV and formula V, as defined above and as detailed below, contain functional groups reactive towards free radical polymerization, preferably vinyl, allyl or acrylic functional groups. Thus, the polymerizable electrolyte should polymerize with any of the aforementioned monomers a).

With respect to compound (b 1) of formula IV, the cation is imidazolium ring based and becomes covalently bonded to the adhesive matrix upon completion of the selected cure profile: the counter anion (a) is free to move within the polymer matrix. In contrast, with respect to the compound (b 2) of formula V, the anion of the polymerizable electrolyte becomes covalently bonded to the binder matrix upon curing, and the cation based on the imidazolium ring is free to move in the matrix.

Preferred compounds b 1) which may be present alone or in combination include, but are not limited to: 3-vinyl-1-methyl-1H-imidazolium iodide; 3-vinyl-1-methyl-1H-imidazolium chloride; 3-vinyl-1-methyl-1H-imidazolium bromide; 3-vinyl-1-methyl-1H-imidazolium methanesulfonate; 3-vinyl-1-methyl-1H-imidazolium 1,1,1-trifluoro-N- [ (trifluoromethyl) sulfonyl ] methanesulfonamide; 3-vinyl-1-ethyl-1H-imidazolium 1,1,1-trifluoro-N- [ (trifluoromethyl) sulfonyl ] methanesulfonamide; 3-vinyl-1-methyl-1H-imidazolium hexafluorophosphate; 3-vinyl-1-methyl-1H-imidazolium 4-methylbenzenesulfonate; 3-vinyl-1-methyl-1H-imidazolium tetrafluoroborate; 3-vinyl-1-ethyl-1H-imidazolium iodide; 3-vinyl-1-ethyl-1H-imidazolium bromide; 3-vinyl-1-ethyl-1H-imidazolium 1,1,1-trifluoro-N- [ (trifluoromethyl) sulfonyl ] methanesulfonamide; 3-vinyl-1-ethyl-1H-imidazolium hexafluorophosphate; 3-vinyl-1-ethyl-1H-imidazolium tetrafluoroborate; 3-vinyl-1- (1-methylethyl) -1H-imidazolium bromide; 3- (1,1-dimethylethyl) -1-vinyl-1H-imidazolium bromide; 3-vinyl-1-propyl-1H-imidazolium bromide; 3-vinyl-1- (phenylmethyl) -1H-imidazolium bromide; 1-vinyl-3- (4-methylphenyl) -1H-imidazolium chloride; 3-vinyl-1- (1-methylpropyl) -1H-imidazolium chloride; 1-butyl-3-vinyl-1H-imidazolium bromide; 3- [ (4-vinylphenyl) methyl ] -1-methyl-iodide; 3- [ (4-vinylphenyl) methyl ] -1-methyl-1H-imidazolium chloride; 3- [ (4-vinylphenyl) methyl ] -1-methyl-1H-imidazolium 1,1,1-trifluoro-N- [ (trifluoromethyl) sulfonyl ] methanesulfonamide; 3- [ (4-vinylphenyl) methyl ] -1-methyl-1H-imidazolium hexafluorophosphate; 3- [ (4-vinylphenyl) methyl ] -1-methyl-1H-imidazolium tetrafluoroborate; 3- [ (4-vinylphenyl) methyl ] -1-ethyl-1H-imidazolium chloride; salts of 1- [ (4-vinylphenyl) methyl ] -3-ethyl-1H-imidazolium with 1,1,1-trifluoro-N- [ (trifluoromethyl) sulfonyl ] methanesulfonamide; 1- (3-aminopropyl) -3- [ (4-vinylphenyl) methyl ] -1H-imidazolium chloride; 1-butyl-3- [ (4-vinylphenyl) methyl ] -1H-imidazolium chloride.

Preferred compounds b 2) which may be present alone or in combination include, but are not limited to: 1-methyl-3-hexyl-1H-imidazolium 4-vinylbenzenesulfonate; 1-dodecyl-3-vinyl-1H-imidazolium 4-vinylbenzenesulfonate; 1-methyl-3-propyl-1H-imidazolium 4-vinylbenzenesulfonate; and 3-ethyl-1-methyl-1H-imidazolium 4- (1-methylvinyl) benzenesulfonate.

In particular, good results have been obtained in the case where part b) of the composition comprises or consists of at least one compound selected from: 3-methyl-1-hexyl-1H-imidazolium 4-vinylbenzenesulfonate; 3-vinyl-1-ethyl-1H-imidazolium 1,1,1-trifluoro-N- [ (trifluoromethyl) sulfonyl ] methanesulfonamide; and 3-methyl-1-butyl-1H-imidazolium 1,1,1-trifluoro-N- [ (trifluoromethyl) sulfonyl ] methanesulfonamide.

According to a second aspect of the present invention, there is provided a bonded structure comprising:

a first layer of material having a conductive surface; and

a second layer of material having a conductive surface,

wherein a cured electrochemically debondable adhesive composition as defined above and in the appended claims is disposed between the first material layer and the second material layer.

According to a third aspect of the present invention, there is provided a method of debonding the bonded structure as defined above and in the appended claims, the method comprising the steps of:

i) Applying a voltage across the two surfaces to form an anode interface and a cathode interface; and

ii) debonding the surface.

Preferably, step i) of the method is characterized by at least one of the following:

a) An applied voltage of 1 to 100V; and

b) The voltage is applied for a duration of 1 second to 180 minutes.

By applying an electrical potential across the adhesive layer between the composition and the conductive surface, the adhesive properties of the composition are destroyed. Without intending to be bound by theory, it is believed that the faradaic 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 therebetween. This interfacial failure can be the result of one or more processes (e.g., chemical degradation of the debondable material, gas evolution at the interface, and/or embrittlement of the material due to changes in the crosslink density of the adhesive composition).

Definition of

As used herein, the singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise.

As used herein, the term "comprising" is synonymous with "including" or "containing" and is inclusive or open-ended and does not exclude additional unrecited members, elements or method steps.

As used herein, the term "consisting of … …" excludes any element, ingredient, member or method step not specified.

When equivalents, concentrations, dimensions, and other parameters are expressed as ranges, preferred ranges, upper values, lower values, or preferred upper and lower values, it is understood that any range that can be obtained by combining any upper value or preferred value with any lower value or preferred value is also specifically disclosed, whether or not the obtained range is explicitly recited in the context.

Furthermore, according to standard understanding, the weight range denoted "0 to x" specifically includes 0 wt%: the ingredients defined by the ranges may be absent from the composition or may be present in the composition in an amount up to x weight percent.

The words "preferred," "preferably," "desirably," and "particularly" are used herein generally to refer to embodiments of the disclosure that may provide particular benefits under certain circumstances. However, recitation of one or more possibly preferred, desired, or particular embodiments does not imply that other embodiments are not useful, and is not intended to exclude those other embodiments from the scope of the disclosure.

As used throughout this application, the word "may" is used in a permissive sense (i.e., meaning having the potential to), rather than the mandatory sense.

As used herein, room temperature is 23 ℃. + -. 2 ℃. As used herein, "ambient conditions" means the temperature and pressure of the environment in which the composition is located or in which the coating or the substrate of the coating is located.

"two-component (2K) composition" in the context of the present invention is understood to be a composition in which: wherein the first component (1) and the second component (2) have to be stored in separate containers due to their (high) reactivity. The two parts are mixed just shortly before application and then reacted, usually without additional activation, with bond formation and thus formation of the polymer network. In this context, higher temperatures may be applied to accelerate the crosslinking reaction.

As used herein, the term "electrochemically debondable" means that after the adhesive cures, the bond strength may decrease by at least 50% after applying a potential of 50V for a duration of up to 60 minutes. The cured adhesive is applied between two substrates bonded by the adhesive such that an electrical current flows through the adhesive bond layer. The adhesive Strength was measured by a Tensile Lap Shear (TLS) Test conducted at room temperature and based on ASTM D3163-01 Standard Test Method for Determining the Strength of Adhesively Bonded Rigid Plastic Lap Shear Joints in Shear by tensile load (Standard Test Method for Determining the Strength of adhesive Bonded Rigid Plastic Lap Shear Joints in Shear by tensile testing). The bond overlap area was 2.5cm by 1.0cm (1 ". Times.0.4"), with a bond thickness of 0.1cm (40 mil).

The term "electrolyte" is used herein according to its standard meaning in the art as a substance containing free ions that can conduct electricity by displacement of charged carrier species. The term is intended to encompass molten electrolytes, liquid electrolytes, semi-solid electrolytes, and solid electrolytes in which at least one of the cationic or anionic components of its electrolyte structure is substantially free to displace, thereby acting as a charge carrier.

The curable adhesive composition of the invention and the cured adhesive obtained therefrom have an "electrolyte function" in that the adhesive material allows conduction of ions (anions, cations, or both anions and cations).

The electrolyte function is understood to result from the ability of the composition and the cured binder to solvate at least one polar ion.

The term "faradaic reaction" means an electrochemical reaction in which a material is oxidized or reduced.

As used herein, the term "monomer" refers to a substance that can undergo a polymerization reaction to provide structural units to the chemical structure of a polymer. As used herein, the term "monofunctional" means having one polymerizable moiety. As used herein, the term "multifunctional" refers to having more than one polymerizable moiety.

As used herein, the term "ethylenically unsaturated monomer" refers to any monomer containing a terminal double bond that is capable of polymerizing under the normal conditions of free radical addition polymerization.

As used herein, the term "equivalent (eq.)" relates to the relative number of reactive groups present in a reaction as is typical in chemical notation.

As used herein, "(meth) acryl" is a shorthand term for "acryl" and/or "methacryl". Thus, the term "(meth) acrylate" refers collectively to both acrylates and methacrylates.

As used herein, "C" is ₁ -C _n An alkyl "group refers to a monovalent group containing 1 to n carbon atoms, which is a radical of an alkane and includes straight-chain and branched organic groups. Due to the fact thatHerein, "C" is ₁ -C ₃₀ An alkyl "group refers to a monovalent group containing 1 to 30 carbon atoms, which is the radical of an alkane and includes both straight-chain and branched organic groups. Examples of alkyl groups include, but are not limited to: a methyl group; an ethyl group; propyl; isopropyl group; n-butyl; an isobutyl group; sec-butyl; a tertiary butyl group; n-pentyl; n-hexyl; a n-heptyl group; and 2-ethylhexyl. In the present invention, such alkyl groups may be unsubstituted or substituted with one or more groups selected from halogen, hydroxyl group, nitrile group (-CN), amide group and amino group (-NH) ₂ ) Is substituted. Where applicable, preference for a given substituent will be indicated in the specification. However, in general, attention should be paid to alkyl groups (C) having 1 to 18 carbon atoms ₁ -C ₁₈ Alkyl) (e.g., alkyl (C) having 1 to 12 carbon atoms ₁ -C ₁₂ Alkyl) or alkyl having 1 to 6 carbon atoms (C) ₁ -C ₆ Alkyl) group).

As used herein, the term "C ₁ -C ₁₈ Hydroxyalkyl "refers to a HO- (alkyl) group having 1 to 18 carbon atoms, wherein the point of attachment of the substituent is through an oxygen atom, and alkyl is as defined above.

"alkoxy" refers to a monovalent group represented by-OA, where a is alkyl: non-limiting examples thereof are methoxy, ethoxy and isopropoxy.

As used herein, the term "C ₁ -C ₆ Alkylene "is defined as a saturated divalent hydrocarbon radical having straight, branched, or cyclic moieties, or combinations thereof, and having from 1 to 6 carbon atoms.

The term "C ₃ -C ₃₀ Cycloalkyl "is to be understood as meaning optionally substituted, saturated, monocyclic, bicyclic or tricyclic hydrocarbon radicals having from 3 to 30 carbon atoms. In general, attention is paid to cycloalkyl groups (C) having 3 to 18 carbon atoms ₃ -C ₁₈ Cycloalkyl) is preferred. Examples of cycloalkyl groups include: a cyclopropyl group; a cyclobutyl group; a cyclopentyl group; a cyclohexyl group; a cycloheptyl group; a cyclooctyl group; adamantane; and norbornane. In the present invention, such cycloalkyl groups may be unsubstituted or substituted by one or more groups selected from halogen, C ₁ -C ₆ Alkyl and C ₁ -C ₆ Substituent of alkoxy.

As used herein, "C" alone or as part of a larger moiety (as in "aralkyl group"), "C" alone or as part of a larger moiety ₆ -C ₁₈ An aryl "group refers to optionally substituted monocyclic, bicyclic, and tricyclic ring systems, wherein a monocyclic ring system is aromatic or at least one of the rings in a bicyclic or tricyclic ring system is aromatic. Bicyclic and tricyclic ring systems include benzo-fused 2-3 membered carbocyclic rings. In the present invention, such aryl groups may be unsubstituted or substituted by one or more groups selected from halogen, C ₁ -C ₆ Alkyl and C ₁ -C ₆ Substituent of alkoxy. Exemplary aryl groups include: a phenyl group; (C) ₁ -C ₄ ) Alkylphenyl groups such as tolyl and ethylphenyl; an indenyl group; naphthyl, tetrahydronaphthyl, tetrahydroindenyl; a tetrahydroanthracenyl group; and an anthracene group. In addition, preference for phenyl groups can be noted.

As used herein, "C" is ₂ -C ₂₀ Alkenyl "refers to a hydrocarbon group having 2 to 20 carbon atoms and at least one ethylenically unsaturated unit. The alkenyl group may be linear, branched or cyclic, and may be optionally substituted. As understood by those of ordinary skill in the art, the term "alkenyl" also includes groups having a "cis (cis)" configuration and a "trans (trans)" configuration, or alternatively an "E" configuration and a "Z" configuration. However, in general, it should be noted that the carbon atoms (C) are those containing 2 to 10 carbon atoms _2-10 ) Or containing 2 to 8 carbon atoms (C) _2-8 ) Preferred is unsubstituted alkenyl of (a). Said C is ₂ -C ₁₂ Examples of alkenyl groups include, but are not limited to: -CH ═ CH ₂ ；—CH═CHCH ₃ ；—CH ₂ CH═CH ₂ ；—C(═CH ₂ )(CH ₃ )；—CH═CHCH ₂ CH ₃ ；—CH ₂ CH═CHCH ₃ ；—CH ₂ CH ₂ CH═CH ₂ ；—CH═C(CH ₃ ) ₂ ；—CH ₂ C(═CH ₂ )(CH ₃ )；—C(═CH ₂ )CH ₂ CH ₃ ；—C(CH ₃ )═CHCH ₃ ；—C(CH ₃ )CH═CH ₂ ；—CH═CHCH ₂ CH ₂ CH ₃ ；—CH ₂ CH═CHCH ₂ CH ₃ ；—CH ₂ CH ₂ CH═CHCH ₃ ；—CH ₂ CH ₂ CH ₂ CH═CH ₂ ；—C(═CH ₂ )CH ₂ CH ₂ CH ₃ ；—C(CH ₃ )═CHCH ₂ CH ₃ ；—CH(CH ₃ )CH═CHCH；—CH(CH ₃ )CH ₂ CH═CH ₂ ；—CH ₂ CH═C(CH ₃ ) ₂ (ii) a 1-cyclopent-1-enyl; 1-cyclopent-2-enyl; 1-cyclopent-3-enyl; 1-cyclohex-1-enyl; 1-cyclohex-2-enyl; and 1-cyclohexyl-3-alkenyl.

As used herein, "alkylaryl" refers to an aryl group substituted with an alkyl group, and "substituted alkylaryl" refers to an alkylaryl group further bearing one or more substituents described above. Furthermore, as used herein, "aralkyl" means an alkyl group substituted with an aryl group as defined above.

As used herein, the term "hetero" refers to a group or moiety containing one or more heteroatoms selected from N, O, si, P, and S. Thus, for example, "heterocycle" refers to a cyclic group having N, O, si, P, or S as part of the ring structure. The "heteroalkyl", "heterocycloalkyl" and "heteroaryl" moieties are alkyl, cycloalkyl and aryl, respectively, as defined above containing N, O, si, P or S as part of their structure.

For completeness, the term "C ₂ -C ₃₀ Heteroalkyl "refers to an" alkyl "group in which at least one carbon atom has been replaced with a heteroatom, the group having a total of 2 to 30 carbon atoms. A specific example of such heteroalkyl is "C ₂ -C ₁₈ Alkoxyalkyl ", which refers herein to an alkyl group having an alkoxy substituent as defined above, and wherein the (alkyl-O-alkyl) moiety contains a total of from 1 to 18 carbon atoms: such groups include methoxymethyl (-CH) ₂ OCH ₃ ) 2-methoxyethyl (-CH) ₂ CH ₂ OCH ₃ ) And 2-ethoxyethyl-CH ₂ CH ₂ OCH ₂ CH ₃ ). A further example of heteroalkyl is "C ₂ -C ₃₀ Aminoalkyl ", which is meant herein to be substituted by at least one substituent selected from the group consisting of-NH (R '), -N (R ') (R ') and N ⁺ (R ') (R ') substituted alkyl, wherein R ', R ' and R ' are C ₁ -C ₆ Alkyl, with the proviso that the group contains a total of 2 to 30 carbon atoms: such groups include 2- (dimethylamino) ethyl, 2- (diethylamino) ethyl and 2- (trimethylamino) ethyl.

The term "C ₁ -C ₉ Heteroaryl "denotes an aromatic group having 1 to 9 carbon atoms and 1 to 4 heteroatoms, which groups may be attached via heteroatoms (if applicable) or carbon atoms. The heteroaryl ring may be fused or otherwise connected to one or more heteroaryl rings, aromatic or non-aromatic hydrocarbon rings, or heterocycloalkyl rings. Examples of heteroaryl groups include, but are not limited to: pyridine; furan; thiophene; 5,6,7,8-tetrahydroisoquinoline; a pyrimidine; a thienyl group; benzothienyl; a pyridyl group; a quinolyl group; a pyrazinyl group; a pyrimidinyl group; an imidazolyl group; a benzimidazolyl group; a furyl group; a benzofuranyl group; a thiazolyl group; a benzothiazolyl group; an isoxazolyl group; an oxadiazolyl group; an isothiazolyl group; benzisothiazolyl; a triazolyl group; a tetrazolyl group; a pyrrolyl group; an indolyl group; a pyrazolyl group; and a benzopyrazolyl group.

The term "C ₂ -C ₈ Heterocycloalkyl "means a saturated cyclic hydrocarbon group having 2 to 8 carbon atoms and 1 to 4 heteroatoms, which groups may be attached via heteroatoms (if applicable) or carbon atoms. The heterocycloalkyl ring may be optionally fused or otherwise connected to other heterocycloalkyl and/or non-aromatic hydrocarbon rings. Preferred heterocycloalkyl groups have 3 to 7 members. Examples of heterocycloalkyl groups include, but are not limited to: piperazine; morpholine; piperidine; tetrahydrofuran; a pyrrolidine; pyrazole; a piperidinyl group; a piperazinyl group; morpholinyl; and a pyrrolidinyl group.

As used herein, the term "aliphatic" includes saturated and unsaturated, non-aromatic, straight-chain, branched, acyclic, or cyclic hydrocarbons, which are optionally substituted with one or more functional groups, provided that the substitution results in the formation of a stable moiety. As will be understood by those skilled in the art, "aliphatic" is intended to include alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, and cycloalkynyl moieties.

As used herein, "aromatic" refers to the primary group of unsaturated cyclic hydrocarbons containing one or more rings, which groups may contain carbon (C), nitrogen (N), oxygen (O), sulfur (S), boron (B), or any combination thereof. At least some carbon is included. Aromatic includes both aryl and heteroaryl rings. The aryl or heteroaryl ring may also be substituted with additional aliphatic, aromatic or other groups, provided that the substitution results in the formation of a stable moiety.

As used herein, the term "free radical initiator" refers to any chemical species that decomposes upon exposure to sufficient energy (in the form of radiation, heat, etc.) into two moieties that are uncharged but each has at least one unpaired electron. For the sake of completeness, the term "radical initiator" includes thermal radical initiators and radical photoinitiators, which can be activated by an energy-carrying activation beam (such as electromagnetic radiation) when irradiated with the energy-carrying activation beam: thermal free radical initiators are preferably used herein.

The molecular weights of the macromolecular, oligomeric, and polymeric components referred to in this specification to describe the curable compositions can be measured using Gel Permeation Chromatography (GPC) using polystyrene calibration standards, as performed according to ASTM 3536.

Unless otherwise specified, the viscosity of the coating compositions described herein is measured using a brookfield viscometer at standard conditions of 20 ℃ and 50% Relative Humidity (RH). The calibration method, rotor type and rotational speed of the brookfield viscometer are selected according to the manufacturer's instructions to be suitable for the composition to be measured.

Detailed Description

a) Nonionic matrix monomers

The compositions of the present invention comprise at least one ethylenically unsaturated nonionic monomer which is (co) polymerized to produce a matrix of debondable adhesive. The monomers a) can in principle be any ethylenically unsaturated nonionic monomer. However, the invention is particularly applicable to such compositions: wherein the (meth) acrylic monomer comprises at least 50 mole%, preferably at least 75 mole%, of the total molar amount of ethylenically unsaturated nonionic monomer present.

a1 Aliphatic and alicyclic (meth) acrylate monomers

In an important embodiment of the invention, the composition of the invention comprises from 40 to 95% by weight, preferably from 45 to 90% by weight, based on the weight of the composition, of a 1) at least one (meth) acrylate monomer represented by formula I:

H ₂ C＝CGCO ₂ R ¹ (I)

R ¹ Selected from the group consisting of: c ₁ -C ₃₀ An alkyl group; c ₂ -C ₃₀ A heteroalkyl group; c ₃ -C ₃₀ A cycloalkyl group; c ₂ -C ₈ A heterocycloalkyl group; c ₂ -C ₂₀ An alkenyl group; and C ₂ -C ₁₂ Alkynyl.

For example, R ¹ May be selected from C ₁ -C ₁₈ Alkyl radical, C ₂ -C ₁₈ Heteroalkyl group, C ₃ -C ₁₈ Cycloalkyl radical, C ₂ -C ₈ Heterocycloalkyl radical, C ₂ -C ₈ Alkenyl and C ₂ -C ₈ Alkynyl.

Desirably, the one or more monomers a 1) are characterized by: r ¹ Is selected from C ₁ -C ₁₈ Alkyl and C ₃ -C ₁₈ A cycloalkyl group. This preferred statement is expressly intended to include where R ¹ Is C ₁ -C ₆ This embodiment of hydroxyalkyl groups.

Examples of (meth) acrylate monomers a 1) according to formula (I) include, but are not limited to: methyl (meth) acrylate; ethyl (meth) acrylate; butyl (meth) acrylate; hexyl (meth) acrylate; 2-ethylhexyl (meth) acrylate; dodecyl (meth) acrylate; lauryl (meth) acrylate; cyclohexyl (meth) acrylate; isobornyl (meth) acrylate; 2-hydroxyethyl (meth) acrylate (HEMA); 2-hydroxypropyl (meth) acrylate; ethylene glycol monomethyl ether (meth) acrylate; ethylene glycol monoethyl ether (meth) acrylate; ethylene glycol monododecyl ether (meth) acrylate; diethylene glycol monomethyl ether (meth) acrylate; trifluoroethyl (meth) acrylate; and perfluorooctyl (meth) acrylate.

a2 Aromatic (meth) acrylate monomers

The composition of the present invention may further comprise 0 to 30 weight percent, such as 0.1 to 30 weight percent, 0.1 to 25 weight percent, or 0.1 to 15 weight percent, based on the weight of the composition, of a 2) at least one (meth) acrylate monomer represented by formula II:

H ₂ C＝CQCO ₂ R ² (ii)

wherein: q may be hydrogen, halogen or C ₁ -C ₄ An alkyl group; and is

R ² May be selected from C ₆ -C ₁₈ Aryl radical, C ₁ -C ₉ Heteroaryl, C ₇ -C ₁₈ Alkylaryl and C ₇ -C ₁₈ An aralkyl group.

Exemplary (meth) acrylate monomers a 2) according to formula (II) that may be used alone or in combination include, but are not limited to: benzyl (meth) acrylate; phenoxyethyl (meth) acrylate; phenoxy diethylene glycol (meth) acrylate; phenoxypropyl (meth) acrylate; and phenoxydipropylene glycol (meth) acrylate.

a3 (meth) acrylate functionalized oligomers

In an important embodiment of the present invention, which is not intended to be mutually exclusive with the inclusion of aliphatic and cycloaliphatic monomers (a 1) and aromatic monomers (a 2), the composition of the present invention should comprise from 0 to 50 wt.%, preferably from 5 to 25 wt.%, based on the weight of the composition, of a 3) of at least one (meth) acrylate functionalized oligomer. The oligomer may have one or more acrylate and/or methacrylate groups attached to the oligomer backbone, and the (meth) acrylate functionality may be located at a terminal position of the oligomer and/or may be distributed along the oligomer backbone.

Preferably, the at least one (meth) acrylate functionalized oligomer: i) Having two or more (meth) acrylate functional groups per molecule; and/or ii) a weight average molecular weight (Mw) of 300 to 1000 daltons.

Examples of such oligomers that may be used alone or in combination include, but are not limited to: (meth) acrylate-functionalized urethane oligomers, such as (meth) acrylate-functionalized polyester urethanes and (meth) acrylate-functionalized polyether urethanes; (meth) acrylate-functionalized polyepoxide resin; (meth) acrylate functionalized polybutadiene; (meth) acrylic polyol (meth) acrylate; a polyester (meth) acrylate oligomer; a polyamide (meth) acrylate oligomer; and a polyether (meth) acrylate oligomer. Such (meth) acrylate functionalized oligomers and methods for their preparation are disclosed, inter alia, in: U.S. Pat. No. 4,574,138; U.S. Pat. No. 4,439,600; U.S. Pat. No. 4,380,613; U.S. Pat. nos. 4,309,526; U.S. Pat. No. 4,295,909; U.S. Pat. No. 4,018,851; U.S. Pat. No. 3,676,398; U.S. Pat. No. 3,770,602; U.S. Pat. No. 4,072,529; U.S. Pat. No. 4,511,732; U.S. Pat. No. 3,700,643; U.S. Pat. No. 4,133,723; U.S. Pat. No. 4,188,455; U.S. Pat. No. 4,206,025; U.S. Pat. No. 5,002,976. Among the above polyether (meth) acrylate oligomers, specific examples include, but are not limited to: PEG 200DMA (n ≈ 4); PEG400 DMA (n ≈ 9); PEG 600DMA (n ≈ 14); and PEG 800DMA (n ≈ 19), where the number assigned (e.g., 400) represents the weight average molecular weight of the diol portion of the molecule.

The present invention does not exclude the presence of other ethylenically unsaturated nonionic monomers which do not conform to the definition of a 1), a 2) and a 3). However, the addition of such additional monomers should be limited to the following conditions: the total amount of ethylenically unsaturated nonionic monomer should not exceed 95% by weight, based on the total weight of the composition. Desirably, the total amount of ethylenically unsaturated nonionic monomer should not exceed 90 weight percent, based on the total weight of the composition.

Without intending to limit the invention, such additional ethylenically unsaturated nonionic monomers may include: silicone (meth) acrylate monomers as taught and claimed in U.S. Pat. No. 5,605,999 (Chu)Those of intensive care, or sexual care; α, β -ethylenically unsaturated monocarboxylic acids having 3 to 5 carbon atoms, such as acrylic acid, methacrylic acid, crotonic acid; c of crotonic acid ₁ -C ₁₈ An alkyl ester; alpha, beta-ethylenically unsaturated dicarboxylic acids containing from 4 to 6 carbon atoms and the anhydrides, monoesters and diesters of those acids; vinyl esters, such as vinyl acetate, vinyl propionate, and VEOVA available from Shell Chemical Company ^TM A series of monomers; vinyl halides and vinylidene halides; vinyl ethers, such as vinyl ethyl ether; vinyl ketones including alkyl vinyl ketones, cycloalkyl vinyl ketones, aryl vinyl ketones, arylalkyl vinyl ketones, and arylcycloalkyl vinyl ketones; aromatic or heterocyclic aliphatic vinyl compounds; poly (meth) acrylates of alkane polyols, such as ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, butylene glycol di (meth) acrylate and neopentyl glycol di (meth) acrylate, hexanediol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, glycerol tri (meth) acrylate and pentaerythritol tetra (meth) acrylate; poly (meth) acrylates of alkylene oxide polyols, such as diethylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, dibutylene glycol di (meth) acrylate, di (1,5-pentanediol) dimethacrylate; polyethylene glycol di (meth) acrylate; and bisphenol a di (meth) acrylates, such as ethoxylated bisphenol a (meth) acrylate ("EBIPMA").

Representative examples of other ethylenically unsaturated polymerizable nonionic monomers include, but are not limited to: ethylene Glycol Dimethacrylate (EGDMA); fumaric, maleic and itaconic anhydrides and C ₁ -C ₄ Monoesters and diesters of alcohols (e.g., methanol, ethanol, propanol, isopropanol, butanol, isobutanol, and tert-butanol). Representative examples of vinyl monomers include, but are not limited to, compounds such as: vinyl acetate; vinyl propionate; vinyl ethers, such as vinyl ethyl ether; and vinyl ethanone. Representative examples of aromatic or heterocyclic aliphatic vinyl compounds include, but are not limited to, compounds such as: styrene, styrene,Alpha-methylstyrene, vinyltoluene, tert-butylstyrene, 2-vinylpyrrolidone, 5-ethylidene-2-norbornene, and also 1-vinylcyclohexene, 3-vinylcyclohexene and 4-vinylcyclohexene.

b) Electrolyte

The composition of the present invention comprises from 0.9 to 50 wt%, such as from 5 to 50 wt% or from 10 to 45 wt%, of b) at least one polymerizable ionic compound, wherein the polymerizable ionic compound comprises:

b1 At least one compound according to formula IV:

and/or

b2 At least one compound according to formula V):

wherein: r ⁷ Selected from the group consisting of: c ₁ -C ₃₀ An alkyl group; c ₂ -C ₈ An alkenyl group; c ₁ -C ₃₀ A heteroalkyl group; c _3- C ₃₀ A cycloalkyl group; c ₆ -C ₁₈ An aryl group; c ₁ -C ₉ A heteroaryl group; c _7- C ₁₈ An alkylaryl group; c _2- C ₅ A heterocycloalkyl group; or-R ^a -C(＝O)-R ^b Wherein R is ^a Is C ₁ -C ₆ Alkylene, and R ^b Is C ₁ -C ₆ An alkyl group;

R ⁹ is H or C ₁ -C ₄ An alkyl group;

a is a non-polymerizable anion;

t is an ethylenically unsaturated anion;

d and m are each integers having a value of at least 1;

e and n have values such that the compound is electrically neutral; and is

Is a covalent bond, C ₁ -C ₂ Alkylene radical, -CH ₂ OC(＝O)-、-CH ₂ CH ₂ OC (= O) -, p-benzyl, or p-tolyl.

In the above formula, preferably, R ⁷ Is selected from C ₁ -C ₁₂ An alkyl group; c ₂ -C ₆ An alkenyl group; c ₁ -C ₁₂ A heteroalkyl group; c _3- C ₁₈ A cycloalkyl group; c ₆ -C ₁₈ An aryl group; c ₁ -C ₉ A heteroaryl group; c _7- C ₁₈ An alkylaryl group; c _2- C ₅ A heterocycloalkyl group; or-R ^a -C(＝O)-R ^b Wherein R is ^a Is C ₁ -C ₆ Alkylene, and R ^b Is C ₁ -C ₆ An alkyl group. More particularly, R ⁷ Is selected from C ₁ -C ₈ An alkyl group; c ₂ -C ₄ An alkenyl group; c ₁ -C ₈ A heteroalkyl group; c _3- C ₁₂ A cycloalkyl group; c ₆ -C ₁₈ An aryl group; c ₁ -C ₉ A heteroaryl group; c _7- C ₁₈ An alkylaryl group; c _2- C ₅ A heterocycloalkyl group; or-R ^a -C(＝O)-R ^b Wherein R is ^a Is C ₁ -C ₄ Alkylene, and R ^b Is C ₁ -C ₄ An alkyl group. Considering R ⁷ May be an alkenyl group, it is noted that the imidazolium moiety may have more than one ethylenically unsaturated group: in this regard, exemplary portions include: 1-3-divinyl-1-H-imidazolium; and 3-vinyl-1- (2-propen-1-yl) -1-H-imidazolium.

Each R ⁸ Preferably independently selected from H or C ₁ -C ₆ Alkyl, more particularly independently selected from H or C ₁ -C ₂ An alkyl group. Preference may be given to at least one R ⁸ Is H. R ⁹ Preferably H or C ₁ -C ₂ Alkyl, and more particularly H or methyl.

Preferably, each R ¹⁰ Independently selected from C ₁ -C ₁₂ An alkyl group; c ₁ -C ₁₂ A heteroalkyl group; c _3- C ₁₈ A cycloalkyl group; c ₆ -C ₁₈ An aryl group; c ₁ -C ₉ A heteroaryl group; c _7- C ₁₈ An alkylaryl group; c _2- C ₅ A heterocycloalkyl group; or-R ^a -C(＝O)-R ^b Wherein R is ^a Is C ₁ -C ₆ Alkylene, and R ^b Is C ₁ -C ₆ An alkyl group. More particularly, R ¹⁰ Selected from: c ₁ -C ₈ An alkyl group; c ₁ -C ₈ A heteroalkyl group; c _3- C ₁₂ A cycloalkyl group; c ₆ -C ₁₈ An aryl group; c ₁ -C ₉ A heteroaryl group; c _7- C ₁₈ An alkylaryl group; c _2- C ₅ A heterocycloalkyl group; or-R ^a -C(＝O)-R ^b Wherein R is ^a Is C ₁ -C ₄ Alkylene, and R ^b Is C ₁ -C ₄ An alkyl group.

With respect to compounds of formula IV, anion a is typically selected from: fluoride ions; chloride ions; bromide ions; iodide ions; perchlorate radicals; nitrate radical; nitrite radical; phosphate radical; sulfate radical; sulfite radicals; a carbonate group; bicarbonate radical; hydrogen phosphate radical; hydrogen sulfate radical; hydrogen sulfite radical; dihydrogen phosphate radical; a trifluorophosphate group; hexafluorophosphate radicals; methyl sulfate radical; ethyl sulfate radical; methyl carbonate radical; a methylsulfonate group; an ethyl sulfonate group; 4-methylbenzenesulfonate; diethyl phosphate radical; formate; acetate radical; propionate; tartrate radical; caprylic acid radical; bis (2,4,4-trimethylpentyl) phosphinate; bis (malonato) borate (bis (malonato) borate); bis (oxalato) borate; bis (pentafluoroethyl) phosphinate; tetracyanoborate; tetrafluoroborate radical; bis (phthalato) borate (bis (phthalato) borate); bis (salicylato) borate; bis (trifluoromethanesulfonate) imide (bis (trifluoromethylsulfonate) imide); bis (trifluoromethanesulfonyl) methane; bis (trifluoromethyl) imidoate; tetrakis (bisulfate) borate; tetrakis (methylsulfonato) borate; a trifluoromethyl sulfonate group; tris (heptafluoropropyl) trifluorophosphate; tris (nonafluorobutyl) trifluorophosphate; tris (pentafluoroethyl) trifluorophosphate; tris (pentafluoroethylsulfonyl) trifluorophosphate; trichlorozincate radical; trifluoroacetic acid radical; a bromoaluminate radical; chloroaluminate radicals; a cupric chloride radical; thiocyanate; a tosylate group; and dicyandiamide.

Preferably, the anion a is selected from: fluoride ions; chloride ions; bromide ions; iodide ions; perchlorate radicals; a nitrate radical; formate; acetate radical; caprylic acid radical; tetrafluoroborate radical; a trifluoro phosphate radical; hexafluorophosphate radicals; methyl sulfate radical; ethyl sulfate radical; methyl carbonate radical; a methylsulfonate group; 4-methylbenzenesulfonate; a trifluoromethyl sulfonate group; bis (trifluoromethylsulfonate) imide, trifluorophosphate, and trifluoroacetate; and tris (perfluoroethyl) trifluorophosphate.

More particularly, the anion a is selected from: fluoride ions; chloride ions; bromide ions; iodide ions; tetrafluoroborate; hexafluorophosphate radicals; methyl sulfate radical; ethyl sulfate radical; a methylsulfonate group; 4-methylbenzenesulfonate; and bis (trifluoromethylsulfonate) imide.

The anion T may be selected from: an ethylenically unsaturated carboxylate anion (R-COO-); ethylenically unsaturated sulfonate anion (R-SO) ₃ ^- ) (ii) a Ethylenically unsaturated phosphonate anion (R-PO) ₃ ^2- ) (ii) a Olefinic bondAn unsaturated phosphinate anion of the formula (R-P (H) O ₂ ^- ) (ii) a And ethylenically unsaturated phosphate anion (R-O-PO) ₃ ^2- ) Wherein R is an organic group containing ethylenic unsaturation, which group polymerizes under normal conditions and is preferably derived from (meth) acrylic acid, vinyl acid or allyl acid.

Representative anions T include: (meth) acrylate; itaconate radical; a maleate radical; a crotonate radical; isocrotonic acid root; vinyl benzoate radical; 2-acrylamido-2-methylpropanesulfonate; sulfoethyl (meth) acrylate; sulfopropyl (meth) acrylate; sulfomethylated acrylamide; an allyl sulfonate group; a vinyl sulfonate group; 4-vinylbenzene sulfonate (4-styrenesulfonate); 4-isopropenylbenzene sulfonate (4-methylstyrene sulfonate); allyl phosphonate; and monoacryloxyethyl phosphate.

Exemplary compounds b 1) according to formula IV include, but are not limited to: 3-vinyl-1-methyl-1H-imidazolium iodide; 3-vinyl-1-methyl-1H-imidazolium chloride; 3-vinyl-1-methyl-1H-imidazolium bromide; 3-vinyl-1-methyl-1H-imidazolium methanesulfonate; 3-vinyl-1-ethyl-1H-imidazolium 1,1,1-trifluoro-N- [ (trifluoromethyl) sulfonyl ] methanesulfonamide; 3-vinyl-1-methyl-1H-imidazolium 1,1,1-trifluoro-N- [ (trifluoromethyl) sulfonyl ] methanesulfonamide; 3-vinyl-1-methyl-1H-imidazolium hexafluorophosphate; 3-vinyl-1-methyl-1H-imidazolium 4-methylbenzenesulfonate; 3-vinyl-1-methyl-1H-imidazolium tetrafluoroborate; 3-vinyl-1-ethyl-1H-imidazolium iodide; 3-vinyl-1-ethyl-1H-imidazolium bromide; 3-vinyl-1-ethyl-1H-imidazolium 1,1,1-trifluoro-N- [ (trifluoromethyl) sulfonyl ] methanesulfonamide; 3-vinyl-1-ethyl-1H-imidazolium hexafluorophosphate; 3-vinyl-1-ethyl-1H-imidazolium tetrafluoroborate; 1,3-divinyl-1H-imidazolium chloride; 1,3-divinyl-1H-imidazolium tetrafluoroborate; 1,3-divinyl-1H-imidazolium hexafluorophosphate; 3-vinyl-1-ethyl-2-methyl-1H-imidazolium iodide; 3-vinyl-1,2-dimethyl-1H-imidazolium iodide; 3-vinyl-1,2-dimethyl-1H-imidazolium chloride; 3-vinyl-2-ethyl-1-methyl-1H-imidazolium iodide; 3- (aminomethyl) -1-vinyl-1H-imidazolium bromide; 3-vinyl-1- (1-methylethyl) -1H-imidazolium bromide; 3- (1,1-dimethylethyl) -1-vinyl-1H-imidazolium bromide; 3-vinyl-1-propyl-1H-imidazolium bromide; 1- (2-aminoethyl) -3-vinyl-1H-imidazolium chloride; 1- (cyanomethyl) -3-vinyl-1H-imidazolium bromide; 1- [2- (diethylamino) ethyl ] -3-vinyl-1H-imidazolium chloride; 3-vinyl-1- (2-propen-1-yl) -1H-imidazolium chloride; 3-vinyl-1- (2-propen-1-yl) -1H-imidazolium 1,1,1-trifluoro-N- [ (trifluoromethyl) sulfonyl ] methanesulfonamide; 3-vinyl-1- (2-propen-1-yl) -1H-imidazolium bromide; 3-vinyl-1- (phenylmethyl) -1H-imidazolium bromide; 1-vinyl-3- (4-methylphenyl) -1H-imidazolium chloride; 3-vinyl-1- (2-hydroxyethyl) -1H-imidazolium chloride; 3-vinyl-1- (1-methylpropyl) -1H-imidazolium chloride; 1-butyl-3-vinyl-1H-imidazolium bromide; 3-vinyl-1- (2-ethoxyethyl) -1H-imidazolium bromide; 1-methyl-3- (2-propen-1-yl) -1H-imidazolium iodide; 1-methyl-3- (2-propen-1-yl) -1H-imidazolium chloride; 1-methyl-3- (2-propen-1-yl) -1H-imidazolium 1,1,1-trifluoro-N- [ (trifluoromethyl) sulfonyl ] methanesulfonamide; 1-methyl-3- (2-propen-1-yl) -1H-imidazolium hexafluorophosphate; 1-methyl-3- (2-propen-1-yl) -1H-imidazolium tetrafluoroborate; 1-ethyl-3- (2-propen-1-yl) -1H-imidazolium iodide; 2-methyl-3- (2-propen-1-yl) -1-propyl-1H-imidazolium bromide; 3- (2-propen-1-yl) -1-propyl-1H-imidazolium bromide; 3- (2-hydroxyethyl) -1- (2-propen-1-yl) -1H-imidazolium bromide; 1-butyl-3- (2-propen-1-yl) -1H-imidazolium bromide; 1,3-di-2-propen-1-yl-1H-imidazolium bromide; 1,3-bis-2-propen-1-yl-1H-imidazolium 1,1,1-trifluoro-N- [ (trifluoromethyl) sulfonyl ] methanesulfonamide; 1,3-di-2-propen-1-yl-1H-imidazolium tetrafluoroborate; 3- (2-hydroxyethyl) -1- (2-propen-1-yl) -1H-imidazolium bromide; 1- (2-cyanoethyl) -3- (2-propen-1-yl) -1H-imidazolium bromide; 1-methyl-3- (2-oxopropyl) -1H-imidazolium tetrafluoroborate; 3- [ (4-vinylphenyl) methyl ] -1-methyl-1H-imidazolium iodide; 3- [ (4-vinylphenyl) methyl ] -1-methyl-1H-imidazolium chloride; 3- [ (4-vinylphenyl) methyl ] -1-methyl-1H-imidazolium 1,1,1-trifluoro-N- [ (trifluoromethyl) sulfonyl ] methanesulfonamide; 3- [ (4-vinylphenyl) methyl ] -1-methyl-1H-imidazolium hexafluorophosphate; 3- [ (4-vinylphenyl) methyl ] -1-methyl-1H-imidazolium tetrafluoroborate; 3- [ (4-vinylphenyl) methyl ] -1-ethyl-1H-imidazolium chloride; salts of 1- [ (4-vinylphenyl) methyl ] -3-ethyl-1H-imidazolium with 1,1,1-trifluoro-N- [ (trifluoromethyl) sulfonyl ] methanesulfonamide; 1- (3-aminopropyl) -3- [ (4-vinylphenyl) methyl ] -1H-imidazolium chloride; 1-butyl-3- [ (4-vinylphenyl) methyl ] -1H-imidazolium chloride; 1-methyl-3- [ [ (1-oxo-2-propen-1-yl) oxy ] methyl ] -1H-imidazolium bromide; 1-ethyl-3- [ [ (1-oxo-2-propen-1-yl) oxy ] methyl ] -1H-imidazolium iodide; and 1-butyl-3- [ [ (1-oxo-2-propen-1-yl) oxy ] methyl ] -1H-imidazolium iodide. For the sake of completeness, such compounds may be present in the compositions of the invention individually or in combinations of two or more.

Without intending to limit the invention, representative compounds according to formula IV include:

for the sake of completeness, in the above description, NTf 2-represents the bistrifluoromethanesulfonylimide anion.

Exemplary compounds b 2) according to formula V include, but are not limited to: 3- (3-cyanopropyl) -1-methyl-1H-imidazolium 2-acrylate; 3-hexyl-1-methyl-1H-imidazolium 2-acrylate; 3-hexadecyl-1-methyl-1H-imidazolium 2-acrylate; 3-ethyl-1-methyl-1H-imidazolium 2-methyl-2-acrylate; 1-methyl-3- (phenylmethyl) -1H-imidazolium 2-methyl-2-acrylate; 3-ethyl-1-methyl-1H-imidazolium 1- [2- [ (1-oxo-2-propen-1-yl) oxy ] ethyl ]1,2-benzenedicarboxylate; 3-ethyl-1-methyl-1H-imidazolium 2-methyl-2- [ (1-oxo-2-propen-1-yl) amino ] -1-propanesulfonate; 3-butyl-1-methyl-1H-imidazolium 3-sulfopropyl 2-methyl-2-acrylate; a salt of 3-ethyl-1-methyl-1H-imidazolium with 2- (phosphonooxy) ethyl 2-methyl-2-acrylate; 1-methyl-3-hexyl-1H-imidazolium 4-vinylbenzenesulfonate; 1-dodecyl-3-vinyl-1H-imidazolium 4-vinylbenzenesulfonate; 3-vinyl-1-hexadecyl-1H-imidazolium 4-vinylbenzenesulfonate; 1-methyl-3-propyl-1H-imidazolium 4-vinylbenzenesulfonate; and 3-ethyl-1-methyl-1H-imidazolium 4- (1-methylvinyl) benzenesulfonate. For the sake of completeness, such compounds may be present in the compositions of the invention individually or in combinations of two or more.

Without intending to limit the invention, representative compounds according to formula V include:

it should be noted that in certain embodiments, the electrically debondable adhesive formulation may contain both: b1 One or more compounds according to formula IV; and b 2) one or more compounds according to formula V. When both are present, it is preferred that the ratio of b 1) to b 2) is 5:1 to 1:1, e.g., 4:1 to 2:1.

c) Free radical initiators

The compositions of the present invention comprise c) at least one free radical initiator. The composition should generally comprise from 0.1 to 10% by weight, for example from 0.1 to 5% by weight or from 0.1 to 2.5% by weight, based on the total weight of the composition, of c) the at least one free radical initiator.

Without intending to limit the invention, one exemplary class of free radical initiators suitable for use herein are organic peroxides selected from, for example: a cyclic peroxide; diacyl peroxides; a dialkyl peroxide; a hydroperoxide; peroxycarbonates (peroxycarbonates); peroxydicarbonates (peroxydicarbanates); a peroxyester; and peroxyketals.

While certain peroxides, such as dialkyl peroxides, have been disclosed as useful initiators, particularly in U.S. Pat. No. 3,419,512 (Lees) and U.S. Pat. No. 3,479,246 (Stapleton), and indeed may have utility herein, hydroperoxides represent a preferred class of initiators for use in the present invention. Furthermore, while hydrogen peroxide itself may be used, the most desirable polymerization initiator is an organic hydroperoxide. For the sake of completeness, included in the definition of hydroperoxide are materials such as organic peroxides or organic peresters which decompose or hydrolyze to form organic hydroperoxides in situ: examples of such peroxides and peresters are cyclohexyl peroxide and hydroxycyclohexyl peroxide, respectively, and tert-butyl perbenzoate.

In an embodiment of the invention, the free radical initiator comprises or consists of at least one hydroperoxide compound represented by the formula:

R ^p OOH

wherein: r ^p Is an aliphatic or aromatic radical containing up to 18 carbon atoms, and

preferably wherein: r ^p Is C ₁ -C ₁₂ Alkyl radical, C ₆ -C ₁₈ Aryl or C ₇ -C ₁₈ An aralkyl group.

As exemplary peroxide initiators which may be used alone or in combination, mention may be made of: cumene Hydroperoxide (CHP); to pair

Alkyl hydroperoxide; tert-butyl hydroperoxide (TBH); tert-butyl perbenzoate; tert-butyl peroxypivalate; di-tert-butyl peroxide; tert-butyl peroxyacetate; tert-butyl peroxy-2-hexanoate; t-amyl hydroperoxide; 1,2,3,4-tetramethylbutyl hydroperoxide; benzoyl peroxide; dibenzoyl peroxide; 1,3-bis (tert-butylperoxyisopropyl) benzene; diacetyl peroxide; 4,4-butyl bis (t-butylperoxy) valerate; p-chlorobenzoyl peroxide; tert-butyl cumyl peroxide; di-tert-butyl peroxide; dicumyl peroxide; 2,5-dimethyl-2,5-di-tert-butylperoxyhexane; 2,5-dimethyl-2,5-di-tert-butyl-peroxy hex-3-yne; and 4-methyl-2,2-di-tert-butylperoxypentane.

Without intending to limit the invention, another exemplary class of free radical initiators suitable for use herein are azo polymerization initiators selected from, for example: azonitriles; azo esters; azoamides; azoamidines; azoimidazoline; and a macroazo initiator.

As representative examples of suitable azo polymerization initiators, mention may be made of: 2,2' -azobis (2-methylbutyronitrile); 2,2' -azobis (isobutyronitrile); 2,2' -azobis (2,4-dimethylvaleronitrile); 2,2' -azobis (4-methoxy-2,4-dimethylvaleronitrile); 1,1' -azobis (cyclohexane-1-carbonitrile); 4,4' -azobis (4-cyanovaleric acid); 2,2' -azobis (2-methylpropionic acid) dimethyl ester; 2,2' -azobis [ 2-methyl-N- (2-hydroxyethyl) propionamide ];2,2' -azobis (N-butyl-2-methylpropionamide); 2,2' -azobis [2- (2-imidazolin-2-yl) propane ] dihydrochloride; 2,2' -azobis [2- (2-imidazolin-2-yl) propane ];2,2' -azobis (2-methylpropionamidine) dihydrochloride; 2,2' -azobis [ N- (2-carboxyethyl) -2-methylpropionamidine ] tetrahydrate; 4,4-a polymer of azobis (4-cyanovaleric acid) and α, ω -bis (3-aminopropyl) polydimethylsiloxane (VPS-1001, available from Wako Pure Chemical Industries, ltd.); and 4,4' -azobis (4-cyanovaleric acid) polyethylene glycol polymer (VPE-0201 available from Wako Pure Chemical Industries, ltd.).

It is not excluded that the composition of the invention may comprise at least one free radical photoinitiator compound which initiates polymerization or hardening of the composition upon irradiation with actinic radiation.

Generally, radical photoinitiators are classified into those that form radicals by cleavage (referred to as "Norrish type I") and those that form radicals by hydrogen abstraction (referred to as Norrish type II). Norrish type II photoinitiators require a hydrogen donor acting as a source of free radicals: since initiation is based on bimolecular reactions, norrish type II photoinitiators are generally slower than free radical based unimolecular formation Norrish type I photoinitiators. On the other hand, norrish type II photoinitiators have better optical absorption properties in the near ultraviolet spectral region. One skilled in the art should be able to select an appropriate free radical photoinitiator based on the actinic radiation employed in the cure and the sensitivity of the one or more photoinitiators at that wavelength.

Preferred free radical photoinitiators are those selected from the group consisting of: benzoylphosphine oxides; an aryl ketone; benzophenone; a hydroxylated ketone; 1-hydroxyphenyl ketone; ketals; and a metallocene. For the sake of completeness, combinations of two or more of these photoinitiators are not excluded from the present invention.

Particularly preferred free radical photoinitiators are those selected from the group consisting of: benzoin dimethyl ether; 1-hydroxycyclohexyl phenyl ketone; benzophenone; 4-chlorobenzophenone; 4-methylbenzophenone; 4-phenylbenzophenone; 4,4' -bis (diethylamino) benzophenone; 4,4' -bis (N, N ' -dimethylamino) benzophenone (michler's ketone); isopropyl thioxanthone; 2-hydroxy-2-methyl propiophenone (Daracur 1173); 2-methyl-4- (methylthio) -2-morpholinopropiophenone; methyl benzoylformate; 2-benzoylbenzoic acid methyl ester; 2-ethylhexyl 4- (dimethylamino) benzoate; ethyl 4- (N, N-dimethylamino) benzoate; phenyl bis (2,4,6-trimethylbenzoyl) phosphine oxide; diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide; and ethyl phenyl (2,4,6-trimethylbenzoyl) phosphinate. Also, combinations of two or more of these photoinitiators are not excluded from the invention for the sake of assurance.

When the composition of the present invention comprises a free radical photoinitiator, irradiation of the curable composition generates reactive species from one or more photoinitiators which initiate the curing reaction. Once the substance is produced, the curing chemistry follows the same thermodynamic rules as any chemical reaction: the reaction rate can be accelerated by heat. The use of thermal processing to enhance the performance of actinic radiation curing of monomers is well known in the art.

As will be appreciated by those skilled in the art, a photosensitizer may be incorporated into the composition to increase the efficiency with which the photoinitiator c) uses the energy delivered. The term "photosensitizer" is used according to its standard meaning to refer to any substance that enhances the rate of photoinitiated polymerization or shifts the wavelength at which polymerization occurs. The photosensitizer should be used in an amount of 0 to 25 wt% based on the weight of the free radical photoinitiator.

The use of free radical (photo) initiators may result in residual compounds in the final cured product from (photo) chemical reactions. The residue can be detected by conventional analytical techniques such as infrared, ultraviolet and NMR spectroscopy, gas or liquid chromatography, and mass spectrometry. Thus, the present invention may comprise a cured matrix (co) polymer and a detectable amount of residue from a free radical (photo) initiator. The residue is present in small amounts and generally does not interfere with the desired physicochemical properties of the final cured product.

d) Solubilizer

The compositions of the present invention may optionally comprise a solubilizing agent. The composition may, for example, contain 0.1 to 10 wt% or 0.1 to 5 wt% of a solubilizer, based on the weight of the composition. The solubilizer has the function of promoting the miscibility of the electrolyte b) in the adhesive composition: the solubilizer may or may not form part of the polymer matrix formed upon curing of the adhesive composition, but does help facilitate ion transfer therein. Thus, the solubilizer is preferably a polar compound and should desirably be a liquid at room temperature.

Suitable classes of solubilizing agents include: polyphosphazene; a polymethylene sulfide; a polyoxyalkylene glycol; a polyethyleneimine; silicone surfactants such as polyalkylsiloxanes and polyoxyalkylene modified polydimethylsiloxanes, including but not limited to poly (C2-C3) oxyalkylene modified polydimethylsiloxanes; copolymers of functionalized polyalkylsiloxanes with epoxy resins, such as copolymers of Polydimethylsiloxane (PDMS) with epoxy resins; a polyol; and a saccharide. For the sake of completeness, fluorinated silicone surfactants (e.g., fluorinated polysilanes) are intended to be encompassed within the term silicone surfactant.

Polyols and saccharides such as ethylene glycol, 1,3-propylene glycol, cyclohexanediol, hydroquinone, catechol, resorcinol, phloroglucinol, pyrogallol, hydroxyhydroquinone, tris (hydroxymethyl) benzene with three methyl or ethyl substituents bonded to the remaining benzene carbon atoms, isosorbide, isomannide (isomannide), isoidide (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, arabitol, xylitol, ribitol, mannitol, sorbitol, inositol, fructose, glucose, mannose, lactose, 1,1,1-tris (hydroxymethyl) propane, 4234 zxft 3534-trimethylolpropane, pentaerythritol, 4264-trimethylolpropane and pentaerythritol, propylene glycol 5364.

Among polyoxyalkylene glycols, it may be noted that particular preference is given to using polyoxy (C) having a weight-average molecular weight of from 200 to 10000g/mol, for example from 200 to 2000g/mol ₂ -C ₃ ) An alkylene glycol.

Additives and auxiliary ingredients

The compositions obtained in the present invention will generally also comprise adjuvants and additives which may impart improved properties to these compositions. For example, adjuvants and additives may impart one or more of the following: improved elasticity; improved elastic recovery; longer allowed processing times; faster curing times; and lower residual tack. Such adjuvants and additives include: a non-polymerizable electrolyte; a toughening agent; conductive particles; a non-conductive filler; a catalyst; a plasticizer; stabilizers, including UV stabilizers; an antioxidant; a reactive diluent; a desiccant; an adhesion promoter; a fungicide; a flame retardant; a rheological adjuvant; a colored pigment or color paste; and/or to a small extent further optionally present non-reactive diluents.

Such adjuvants and additives may be used in such combinations and proportions as are desired, provided they do not adversely affect the characteristics and basic properties of the composition. Although exceptions may be present in some cases, these adjuvants and additives should not amount to more than 20% by weight of the total composition, and preferably should not amount to more than 10% by weight of the composition.

The presence of non-polymerizable electrolytes in the compositions of the present invention is not excluded. Exemplary electrolytes include non-polymerizable salts of cations selected from the group consisting of: ammonium; pyridinium salts; a phosphonium; imidazolium salts; oxazolium (oxazolium); guanidinium (guadinium); and thiazolium. Although there is no particular limitation on the anion of such a non-polymerizable saltBut preferred anions are selected from: halide (halide); PF (particle Filter) ₆ ^- 、CF ₃ SO ₃ ^- 、(CF ₃ SO ₃ ) ₂ N ^- 、CF ₃ CO ₂ ^- And CCl ₃ CO ₂ ^- And a halogen-containing compound; carboxylic acid anions, in particular formate, acetate, propionate, butyrate and lactate; hydroxy carboxylic acid anion; pyridinium (pyridinate) and pyrimidinium (pyrimidinate); carboxylic acid imides, bis (sulfonyl) imides, and sulfonyl imides; sulfates, especially methyl sulfate and ethyl sulfate; sulfite radicals; sulfonates, especially methane sulfonate; and phosphates, in particular dimethylphosphate, diethylphosphate and (2-ethylhexyl) phosphate.

When included in the composition, the non-polymerizable electrolyte should be present in an amount of less than 10 weight percent of the total weight of the polymerizable ionic compound (part b)).

The presence of a toughening agent in the composition of the present invention may facilitate debonding of the cured adhesive. Without intending to be bound by theory, the toughening agent promotes phase separation within the cured adhesive under an applied electrical potential. In particular, good debonding results have been obtained in case the composition of the invention comprises at least one toughening agent selected from: an epoxy resin-elastomer adduct; and a toughening rubber in the form of core-shell particles dispersed in a matrix polymer.

The elastomer-containing adduct may be used alone, or a combination of two or more specific adducts may be used. Further, each adduct may be independently selected from a solid adduct or a liquid adduct at a temperature of 23 ℃. Generally, useful adducts will be characterized by an epoxy resin to elastomer weight ratio of 1:5 to 5:1, e.g., 1:3 to 3:1. Additionally, an instructional reference to suitable epoxy/elastomer adducts is U.S. patent publication 2004/0204551. Further, exemplary commercially available epoxy/elastomer adducts for use herein include, but are not limited to: HYPDX RK8-4 commercially available from CVC Chemical; and B-Tough A3, commercially available from Croda Europe Limited.

The term "core shell rubber" or CSR is used according to its standard meaning in the art to denote a rubber particle core formed of a polymer comprising an elastomeric polymer or a rubbery polymer as a main component and a shell layer formed of a polymer graft-polymerized onto the core. The shell layer partially or completely covers the surface of the rubber particle core during graft polymerization. The core should comprise at least 50% by weight of the core shell rubber particles.

The polymeric material of the core should have a glass transition temperature (T) of not more than 0 ℃ _g ) Preferably a glass transition temperature (T) of-20 ℃ or less, more preferably-40 ℃ or less, even more preferably-60 ℃ or less _g ). The polymer of the shell is the glass transition temperature (T) _g ) A non-elastomeric, thermoplastic or thermosetting polymer above room temperature, preferably above 30 ℃, more preferably above 50 ℃.

Without intending to limit the invention, the core may consist of: diene homopolymers, such as homopolymers of butadiene or isoprene; diene copolymers, for example copolymers of butadiene or isoprene with one or more ethylenically unsaturated monomers, such as vinyl aromatic monomers, (meth) acrylonitrile or (meth) acrylates; polymers based on (meth) acrylate monomers, such as polybutyl acrylate; and silicone elastomers such as polydimethylsiloxanes and crosslinked polydimethylsiloxanes.

Similarly, without intending to limit the invention, the shell may be composed of a polymer or copolymer of one or more monomers selected from the group consisting of: (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 which are ionically crosslinked by the formation of metal carboxylates, in particular by the formation of salts of divalent metal cations. The shell polymer or copolymer may also be covalently crosslinked by monomers having two or more double bonds per molecule.

Preferably, any core shell rubber particles included have an average particle diameter (d 50) of 10nm to 300nm, for example 50nm to 250nm: the particle size refers to the diameter or largest dimension of the particles in the particle distribution and is measured via dynamic light scattering. For the sake of completeness, the present application does not preclude the presence of two or more types of Core Shell Rubber (CSR) particles having 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.

The core shell rubber may be selected from commercially available products, examples of which include: paraloid EXL 2650A, EXL and EXL 2691A available from The Dow Chemical Company; available from Arkema inc

XT100; kane available from Kaneka Corporation>

The MX series, in particular MX 120, MX 125, MX 130, MX 136, MX 551, MX553; and METABLEN SX-006, available from Mitsubishi Rayon.

The composition of the present invention may comprise conductive particles. The composition may, for example, contain 0 to 10 wt% or 0.1 to 5 wt% of conductive particles based on the weight of the composition.

In general, there is no particular intention to limit the shape of the particles used as conductive filler: acicular, spherical, ellipsoidal, cylindrical, beaded, cubic, or flaky particles may be used alone or in combination. Furthermore, it is contemplated that more than one particle type of agglomerates may be used. Also, there is no particular intention to limit the size of the particles used as the conductive filler. However, such conductive fillers will typically have an average volume particle size as measured by laser diffraction/scattering methods of 0.1 to 1500 μm, for example 1 to 1250 μm.

Exemplary conductive particulate fillers include, but are not limited to: silver; copper; gold; palladium; platinum; nickel; gold or silver coated nickel; carbon black; carbon fibers; graphite; aluminum; indium tin oxide; silver coated copper; silver coated aluminum; metal coated glass spheres; a metal-coated filler; a metal-coated polymer; silver coated fibers; silver coated spheres; antimony-doped tin oxide; a conductive nanosphere; nano silver; nano aluminum; nano-copper; nano nickel; a carbon nanotube; and mixtures thereof. Preferably, particulate silver and/or carbon black is used as the conductive filler.

The compositions of the present invention may optionally comprise a non-conductive filler. The composition may, for example, contain 0 to 10 wt% or 0.1 to 5 wt% of the non-conductive particles, based on the weight of the composition.

In general, there is no particular intention to limit the shape of the particles used as non-conductive filler: acicular, spherical, ellipsoidal, cylindrical, beaded, cubic, or flaky particles may be used alone or in combination. Furthermore, it is contemplated that more than one particle type of agglomerates may be used. Also, there is no particular intention to limit the size of the particles used as the non-conductive filler. However, such non-conductive fillers will typically have an average volume particle size as measured by laser diffraction/scattering methods of 0.1 to 1500 μm, for example 1 to 1250 μm.

Exemplary non-conductive fillers include, but are not limited to: calcium carbonate, calcium oxide, calcium hydroxide (lime powder), precipitated and/or pyrogenic silicic acid, zeolites, 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, in particular wood fibers, wood flour, sawdust, cellulose, cotton, pulp, cotton, wood chips, chopped straw, cereal husks, ground walnut shells, and other chopped fibers. Short fibers such as glass fibers, glass filaments, polyacrylonitrile, carbon fibers, kevlar fibers or polyethylene fibers may also be added.

The pyrogenic silicic acid and/or precipitated silicic acid advantageously has a particle size of from 10 to 90m ² BET surface area in g. When they are used, they do not cause any additional increase in the viscosity of the composition according to the invention, but do contribute to the strengthening of the cured composition.

Likewise, it is possible to envisage using a catalyst having a higher BET surface area, advantageously between 100 and 250m ² /gPyrogenic silicic acid and/or precipitated silicic acid as filler: the effect of reinforcing the cured composition is achieved with a smaller proportion by weight of silicic acid due to the larger BET surface area.

Also suitable as non-conductive fillers are hollow spheres with a mineral or plastic shell. For example, these may be under the trade name Glass

Commercially available hollow glass spheres. Plastic-based hollow ball (e.g.. Sup @)>

Or

) Can be used and is described in EP 0 520 426 B1: which are made of an inorganic substance or an organic substance and each have a diameter of 1mm or less, preferably 500 μm or less.

Non-conductive fillers that impart thixotropy to the composition may be preferred for many applications: such fillers are also described as rheological adjuvants, for example hydrogenated castor oil, fatty acid amides, or expandable plastics (such as PVC).

The desired viscosity of the resulting curable composition may determine the amount of filler used. With respect to the latter consideration, the total amount of both the conductive filler and the non-conductive filler present in the composition should not prevent the composition from being readily adaptable for application to a substrate by the selected method. For example, a curable composition intended to be extrudable from a suitable dispensing device (such as a tube) should have a viscosity of 1000 to 150000, preferably 10000 to 100000 mPas.

"plasticizers" for the purposes of the present invention are substances which reduce the viscosity of the composition and thus promote its processability. Herein, the plasticizer may comprise up to 10% by weight or up to 5% by weight, based on the total weight of the composition, and is preferably selected from: a dicarbamate; ethers of monofunctional, linear or branched C4-C16 alcohols, such as Cetiol OE (available from Cognis Deutschland GmbH, dusseldorf); esters of abietic acid, butyric acid, thiobutyric acid, acetic acid, propionic acid and citric acid; esters based on nitrocellulose and polyvinyl acetate; a fatty acid ester; a dicarboxylic acid ester; esters of OH-group-bearing or epoxidized fatty acids; glycolic acid esters; benzoic acid esters; a phosphate ester; a sulfonate ester; trimellitic acid ester; polyether plasticizers, such as capped polyethylene glycols or polypropylene glycols; polystyrene; a hydrocarbon plasticizer; chlorinated paraffin; and mixtures thereof. It should be noted that in principle phthalates can be used as plasticizers, but these are not preferred due to their toxicological potential.

"stabilizer" for the purposes of the present invention is to be understood as meaning an antioxidant, a UV stabilizer, a heat stabilizer or a hydrolysis stabilizer. In this context, the stabilizer may constitute up to 10% by weight or up to 5% by weight in total, based on the total weight of the composition. Standard commercially available examples of stabilizers suitable for use herein include: a sterically hindered phenol; a thioether; benzotriazole; benzophenone; benzoic acid esters; a cyanoacrylate; an acrylate; hindered Amine Light Stabilizer (HALS) type amines; phosphorus; sulfur; and mixtures thereof.

It should be noted that compounds having metal chelating properties may be used in the compositions of the present invention to help enhance the adhesion of the cured adhesive to the substrate surface. Also suitable for use as adhesion promoters are, in addition, acetoacetate-functionalized modified resins sold by King Industries under the trade name K-FLEX XM-B301.

In order to even further increase the shelf life, it is generally recommended to further stabilize the compositions of the invention with respect to moisture penetration by using desiccants. It is also sometimes desirable to reduce the viscosity of the adhesive composition according to the invention for a particular application by using one or more reactive diluents. The total amount of reactive diluent present will generally be from 0 to 10 wt%, for example from 0.1 to 5 wt%, based on the total weight of the composition.

The presence of solvents and non-reactive diluents in the compositions of the invention is also not excluded insofar as it may be useful to adjust the viscosity of the composition. For example, but for illustration only, the composition may contain one or more of the following: xylene; 2-methoxyethanol; IIMethoxyethanol; 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-methyl pyrrolidone; diphenylmethane; diisopropyl naphthalene; petroleum fractions, e.g.

Products (available from Exxon); alkylphenols, such as tert-butylphenol, nonylphenol, dodecylphenol and 8,11,14-pentadecenylphenol; styrenated phenol; a bisphenol; aromatic hydrocarbon resins, especially those containing phenolic groups, such as ethoxylated or propoxylated phenols; an adipate ester; sebacate esters; a phthalate ester; benzoic acid esters; an organic phosphate or sulfonate; and sulfonamides.

In addition to the above, preferably the non-reactive diluents make up less than 10 wt.%, in particular less than 5 wt.% or less than 2 wt.%, based on the total weight of the composition.

Method and use

To form the composition, the above parts are brought together and mixed. It is important that the mixing distributes the polymerizable electrolyte (compound b 1) and/or compound b 2)) homogeneously within the adhesive composition: such thorough and efficient mixing may determine a uniform distribution of charged species within the polymer matrix obtained after curing, thereby providing sufficient ionic conductivity to support electrochemical reactions at the interface with the conductive substrate.

As known in the art, to form a one-part (1K) curable composition, the ingredients of the composition are brought together and uniformly mixed under conditions that inhibit or prevent the reaction of the reactive components: such conditions are readily understood by the skilled person. Thus, it will generally be preferred not to mix the curable ingredients manually, but by a machine (e.g., a static mixer or a dynamic mixer) in a predetermined amount without intentional light irradiation under anhydrous conditions.

For two-component (2K) compositions, the reactive components are brought together and mixed in such a way as to cause hardening thereof. For one-component (1K) compositions and two-component (2K) compositions, the reactive compounds should be mixed under sufficient shear to produce a homogeneous mixture. It is considered that this can be achieved without special conditions or special equipment. That is, suitable mixing devices may include: a static mixing device; a magnetic stir bar device; a wire whisk device (wire whisk device); auger (auger); a batch mixer; a planetary mixer; brabender or C.W.

A type mixer; and high shear mixers such as blade blenders and rotary high speed mixers.

For small-scale liner (liner) applications, which would typically use a volume of less than 2 liters, a preferred package for a two-component (2K) composition would be a side-by-side dual or coaxial cartridge, with two tubular chambers arranged side-by-side or inside each other and sealed with a piston: the driving of these pistons allows the components to be advantageously extruded from the barrel by means of a closely mounted static mixer or dynamic mixer. For larger volume applications, the two components of the composition may be advantageously stored in a drum or pail: in this case, the two components are extruded via a hydraulic press, in particular via a follower plate (follower plate), and supplied via a pipe to a mixing device which ensures a fine and highly uniform mixing of the hardener with the adhesive component. In any case, for any package, it is important that the adhesive component be disposed in an air-tight and moisture-tight seal so that both components can be stored for long periods of time (ideally 12 months or longer).

Non-limiting examples of two-component dispensing apparatus and methods that may be suitable for the present invention include those described in U.S. patent No. 6,129,244 and U.S. patent No. 8,313,006.

Where applicable, the two-component (2K) composition should be broadly formulated to exhibit an initial viscosity (measured immediately after mixing, e.g., up to two minutes after mixing) that does not interfere with the method of applying the composition to a substrate. Furthermore, the two-component (2K) composition should also be formulated to exhibit a pot life of at least 30 minutes and typically at least 60 or 120 minutes, said "pot life" being the time required for the viscosity of the curable composition to reach a value of 2 times the viscosity of a freshly mixed curable composition at 20 ℃ and 50% relative humidity.

According to the broadest method aspect of the present invention, the above-described composition is applied to a substrate and then cured in situ. Prior to application of the composition, it is generally advisable to pretreat the relevant surface to remove foreign substances therefrom: this step (if applicable) may facilitate subsequent adhesion of the composition thereto. Such treatments are known in the art and may be carried out in a single or multi-stage manner, consisting for example of using one or more of the following: an etching treatment with an acid suitable for the substrate and optionally an oxidizing agent; performing acoustic treatment; plasma treatment including chemical plasma treatment, corona treatment, atmospheric pressure plasma treatment and flame plasma treatment; immersing in an aqueous alkaline degreasing bath; treating with an aqueous cleaning emulsion; treatment with a cleaning solvent (e.g., carbon tetrachloride or trichloroethylene); and water rinsing, preferably with deionized water or demineralized water. In those cases where an aqueous alkaline degreasing bath is used, any degreaser remaining on the surface should desirably be removed by rinsing the substrate surface with deionized water or demineralised water.

In some embodiments, adhesion of the coating composition of the present invention to the preferably pretreated substrate may be facilitated by the application of a primer thereto. While one skilled in the art will be able to select an appropriate primer, instructive references for selecting a primer include, but are not limited to: U.S. Pat. No. 3,671,483; U.S. Pat. No. 4,681,636; U.S. Pat. No. 4,749,741; U.S. Pat. No. 4,147,685; and us patent No. 6,231,990.

The composition is then applied to the preferably pretreated, optionally primed surface of the substrate by conventional application methods such as: brushing; roll coating, for example using a 4-applicator roll apparatus in the absence of solvent for the composition or a 2-applicator roll apparatus for the solvent-containing composition; applying a scraper; a printing method; and spray methods including, but not limited to, air atomized spray, air assisted spray, airless spray, and high volume low pressure spray.

As described above, the present invention provides a bonded structure comprising: a first layer of material having a conductive surface; and a second layer of material having an electrically conductive surface, wherein a cured electrochemically debondable adhesive composition as defined above and in the appended claims is disposed between the first layer of material and the second layer of material. To produce such a structure, the adhesive composition may be applied to at least one inner surface of the first material layer and/or the second material layer, and then the two layers are subsequently contacted, optionally under applied pressure, such that the electrically debondable adhesive composition is disposed between the two layers.

It is recommended that the composition is applied to the surface in a wet film thickness of 10 to 5000 μm, for example 50 to 2500 μm. Application of thinner layers in this range is more economical and provides a reduced likelihood of detrimental thick cured areas. However, tight control must be exercised in applying thinner coatings or layers to avoid the formation of both discontinuous cured films and short contacts.

Curing of the applied composition of the invention generally takes place at temperatures of from 40 ℃ to 200 ℃, preferably from 50 ℃ to 190 ℃, in particular from 60 ℃ to 180 ℃. The appropriate temperature depends on the particular compound present and the desired cure rate and can be determined in each case by the person skilled in the art using simple preliminary tests, if necessary. Of course, lower temperature curing in the above range is advantageous because it eliminates the need to substantially heat or cool the mixture from the typically prevailing ambient temperature. Where applicable, however, the temperature of the mixture formed from the ingredients of the composition may be raised above the mixing temperature and/or application temperature using conventional means, including microwave induction.

The invention will be described with reference to the accompanying drawings, in which:

fig. 1a depicts a bonded structure according to a first embodiment of the invention.

Fig. 1b depicts a bonded structure according to a second embodiment of the invention.

Fig. 2a depicts the initial debonding of the structure of the first embodiment when a voltage is applied across the structure.

Fig. 2b depicts the initial debonding of the structure of the second embodiment when a voltage is applied across the structure.

As shown in the attached fig. 1a, a bonded structure is provided in which a cured adhesive layer (10) is disposed between two conductive substrates (11). A layer of non-conductive material (12) may be provided on the conductive substrate (11) to form a more complex bonded structure as depicted in fig. 1 b. Each layer of the conductive substrate (11) is in electrical contact with a power source (13), which power source (13) may be a battery or an alternating current driven Direct Current (DC) source. The positive and negative terminals of the power supply (13) are shown at a fixed location, but those skilled in the art will of course recognize that the polarity of the system may be reversed.

The two electrically conductive substrates (11) are shown in the form of layers which may in particular consist of: a metal film; metal mesh or grid; deposited metal particles; a resin material having conductivity by a conductive element provided therein; or a conductive oxide layer. As exemplary conductive elements, silver wire, single-walled carbon nanotubes and multi-walled carbon nanotubes may be mentioned. As exemplary conductive oxides, mention may be made of: doped indium oxide, such as Indium Tin Oxide (ITO); doped zinc oxide; antimony tin oxide; cadmium stannate; and zinc stannate. In addition to the selection of the conductive material, one skilled in the art will recognize that the effectiveness of the debonding operation may be reduced where the conductive substrate (11) is in the form of a grid or mesh that provides limited contact with the cured adhesive layer (10).

When a voltage is applied between each of the conductive substrates (11), an electric current is supplied to the adhesive composition (10) disposed therebetween. This initiates an electrochemical reaction at the interface of the substrate (11) and the binder composition, which should be understood as being oxidized at a positively charged interface or anode interface and reduced at a negatively charged interface or cathode interface. This reaction is believed to weaken the adhesive bond between the substrates, allowing the debondable composition to be easily removed from the substrates.

As shown in fig. 2a and 2b for illustrative purposes only, debonding occurs at the positive electrode interface, i.e., the interface between the binder composition (10) and the conductive surface (11) in electrical contact with the positive electrode. By reversing the direction of the current flow before separating the substrates, the adhesive bond at the interface of the two substrates can be weakened.

It should be noted, however, that the composition of the binder layer (10) may be adjusted such that debonding occurs at the positive or negative interface or both. For some embodiments, a voltage applied across both surfaces to form an anode interface and a cathode interface will cause debonding to occur simultaneously at the anode and cathode binder/substrate interfaces. In an alternative embodiment, if the composition is not responsive to direct current at both interfaces, the reversed polarity may be used to simultaneously debond both substrate/adhesive interfaces. The current may be applied in any suitable waveform provided that the debonding is allowed to proceed for a sufficient total time at each polarity. In this regard, sinusoidal, rectangular, and triangular waveforms may be suitable and may be applied by a controlled voltage source or a controlled current source.

Without intending to limit the invention, it is believed that the debinding operation can be effectively performed in the event that at least one and preferably both of the following conditions occur: a) An applied voltage of 1 to 100V, for example 20 to 50V; and b) the voltage is applied for a duration of 1 second to 180 minutes, for example 1 second to 30 minutes. In the case where the release of the conductive substrate from the cured adhesive is facilitated by the application of force (e.g., via a weight or spring), the electrical potential may only need to be applied for about a few seconds.

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

Examples

The following materials and abbreviations for said materials are used in the examples:

MMA: methacrylic acid methyl ester

MAA: methacrylic acid

EGDMA: ethylene glycol dimethacrylate

PEG-MEA: polyethylene glycol methyl ether acrylate

Benzyl MA: methacrylic acid benzyl ester

HEMA: (hydroxyethyl) methacrylate

IBOA: acrylic acid isobornyl ester

AIBN: azobisisobutyronitrile, available from Sigma Aldrich

BPO: benzoyl peroxide, available from PanReac Applichem

HEXMIM StSO3: 3-methyl-1-hexyl-1H-imidazolium 4-vinylbenzenesulfonate

EMIM acrylate salt: 1-ethyl-3-methyl-1H-imidazolium acrylate

ViEIM NTf2: 3-vinyl-1-ethyl-1H-imidazolium 1,1,1-trifluoro-N- [ (trifluoromethyl) sulfonyl ] methanesulfonamide

BMIM NTf2: 3-methyl-1-butyl-1H-imidazolium 1,1,1-trifluoro-N- [ (trifluoromethyl) sulfonyl ] methanesulfonamide

PEG400: polyethylene glycol available from Sigma Aldrich

CN966H90: aliphatic polyester-based urethane diacrylate oligomer blended with 10% 2- (2-ethoxyethoxy) ethyl acrylate available from Sartomer

SR9054: acid acrylate adhesion promoters available from Sartomer

Preparation of the first set of formulations: the formulations EDA1 to EDA14 described in table 1a and table 1b below and control 1, control 2 and control 3 were formed under mixing.

TABLE 1a

TABLE 1b

The amounts in parentheses of the polymerizable electrolytes given in table 1a and table 1b are in units of millimoles (mmol).

Control 1, control 2 and control 3 consisted of nonionic matrix monomers that formed the adhesive without any ionic species. The formulations EDA1 to EDA7, EDA9 to EDA11 and EDA13 to EDA14 are based on the copolymerization of a non-ionic matrix monomer with a polymerizable ionic compound.

EDA8 is a mixture of a non-ionic matrix monomer and a cured Polymerizable Electrolyte (PE) copolymer and is obtained as follows: first, viEIM NTf2 (0.359 g) and HexMIM StSO3 (0.104 g) were mixed with azobisisobutyronitrile (0.008 g) at 3600rpm for one minute at high speed; the mixture was then cured at 80 ℃ for 15 minutes, followed by 120 ℃ for 2 hours; finally, the cured material is mixed with the nonionic matrix monomer and azobisisobutyronitrile.

EDA12 forms a reference and is based on a mixture of non-ionic matrix monomers and non-polymerizable ionic compounds (BMIM NTf 2).

The following formulations EDA1 to EDA14 and the application substrate of the control were aluminum (AA 6016) with a thickness of 1.25mm, and the application of the coating composition was carried out using glass beads with a diameter of 100 to 200 micrometers as spacers. The substrate was cut into samples having dimensions of 2.5cm x 10cm for tensile testing. Tensile Lap Shear (TLS) testing was performed at room temperature based on ISO 4587 adhesive-Determination of the tensile lap shear strength of rigid-to-rigid adhesive components (international organization for standardization, 2003). The bond overlap area for each of the substrates was 2.5cm by 1.0cm with a bond thickness of 0.1cm (40 mil). INSTRON 3366 with 10kN cells (cells) was used.

The applied adhesive composition was cured in the overlap region by applying a temperature of 80 ℃ for 15 minutes and a temperature of 120 ℃ for 120 minutes. The bonded structure was then stored at room temperature for 24 hours prior to the initial tensile test.

Example 1

After the 24-hour storage period, tensile lap shear strength was studied before and after applying a constant potential of 50V on the adhesive layer for a duration of up to 30 minutes. The results are reported in table 2 below.

TABLE 2

Adhesive agent	Initial adhesive Strength (MPa)	Adhesive Strength (MPa) after 30 minutes at 50V
			Control 1	2.03(±0.59)	2.11(±0.28)
EDA1	3.67(±0.56)	3.15(±0.06)
			EDA2	2.18(±0.36)	1.48(±0.20)
EDA3	3.44(±0.31)	0
			EDA4	3.07(±0.58)	0.71(±0.62)
EDA5	2.63(±0.51)	1.10(±0.23)
			EDA6	2.66(±0.34)	1.71(±0.12)
EDA7	3.85(±0.71)	2.80(±0.63)
			EDA8	2.09(±0.13)	2.08(±0.33)
EDA9	2.61(±0.09)	0.97(±0.09)
			EDA10	1.98(±0.41)	0
EDA11	2.35(±0.11)	0
			EDA12 (ref.)	1.60(±0.60)	0
Control 2	1.76(±0.77)	1.17(±0.61)
			EDA13	2.60(±0.54)	1.54(±0.12)
Control 3	1.53(±0.63)	2.32(±0.45)
			EDA14	2.67(±0.86)	0

Formulations containing polymerizable ionic compounds increase initial adhesive strength. After application of the voltage, the adhesive strength of the formulations based on the copolymerization of the polymerizable ionic compound with the nonionic matrix monomer decreases.

Example 2

This example investigates the electrical delamination behavior of the adhesive formulation EDA5 described above by measuring the tensile lap shear strength before and after applying different constant potentials on the adhesive layer for durations of up to 30 minutes after said 24-hour pot life. The results are reported in table 3 below.

TABLE 3

Example 3

This example investigates the electrical delamination behavior of some of the above adhesives by measuring the tensile lap shear strength before and after the 24-hour storage period and after a 2-month storage period, before and after applying a constant potential of 50V across the adhesive layer for a duration of up to 30 minutes. The results are reported in table 4 below.

TABLE 4

Formulations based on the copolymerization of nonionic matrix monomers with polymerizable ionic compounds maintain initial adhesive strength after two months and still show a decrease in adhesive strength after application of voltage.

Preparation of the second set of formulations: the formulations EDA15 to EDA19 described in table 5 below and control 4 were formed under mixing.

TABLE 5

Control 4 consisted of a non-ionic matrix monomer that formed the binder without any ionic species. The formulations EDA15 to EDA18 are based on the copolymerization of a non-ionic matrix monomer with a polymerizable ionic compound.

EDA19 forms the reference and is based on a mixture of non-ionic matrix monomers with non-polymerizable ionic compounds (BMIM NTf 2).

The application substrates of the following formulations EDA15 to EDA19 and control 4 were aluminum (AA 6016) with a thickness of 1.25mm and stainless steel (1.4301) with a thickness of 1.5mm, and the application of the coating composition was performed using glass beads with a diameter of 100 to 200 micrometers as spacers. The substrate was cut into samples having dimensions of 2.5cm x 10cm (1 "x 4") for tensile testing. Tensile Lap Shear (TLS) testing was performed at room temperature based on ISO 4587 adhesive-determination of tensile lap shear strength of rigid-to-rigid adhesive assemblies (international organization for standardization, 2003). The bond overlap area for each of the substrates was 2.5cm by 1.0cm with a bond thickness of 0.1cm (40 mil). Zwick Z020 with 20kN elements was used.

The applied adhesive composition was cured in the overlap region by applying a temperature of 80 ℃ for 15 minutes and a temperature of 120 ℃ for 30 minutes. The bonded structure was then stored at room temperature for 24 hours prior to the initial tensile test.

Example 4

After the 24-hour storage period, tensile lap shear strength was studied before and after applying a constant potential of 50V on the adhesive layer for a duration of up to 30 minutes. The results are reported in table 6 below.

TABLE 6

The formulations EDA15 and EDA18 containing the polymerizable ionic compound maintained the initial bond strength, while the formulation EDA17 observed a decrease in initial strength. A 50% reduction in initial strength was observed for formulation EDA19 containing a non-polymerizable ionic liquid. After application of the voltage, the adhesive strength of the formulations based on the copolymerization of the polymerizable ionic compound with the nonionic matrix monomer decreases.

Example 5

This example investigates the electrical delamination behavior of certain of the above adhesives (EDA 15, compared to EDA 19) by measuring the tensile lap shear strength before and after applying a constant potential of 50V on the adhesive layer for a duration of 30 minutes after said 24 hour storage period and after storage periods of 1 week, 1 month, 2 months and 3 months. A climate-controlled chamber (climate chamber) set at 23 ℃ and 50% relative humidity was used. The results are reported in tables 7 and 8 below.

TABLE 7

TABLE 8

Formulation EDA15, based on the copolymerization of a non-ionic matrix monomer with a polymerizable ionic compound, showed a slight decrease (12%) in the adhesive strength after three months. Formulations based on mixtures of non-polymerizable ionic liquids with non-ionic matrix monomers showed a higher reduction (30%) in the adhesive strength to both aluminum and stainless steel after two months. All formulations showed a decrease in adhesive strength after application of the voltage.

In view of the foregoing description and embodiments, it will be evident to a person skilled in the art that equivalent modifications may be made thereto without departing from the scope of the claims.

Claims

1. A curable and electrochemically debondable adhesive composition comprising, based on the weight of the composition:

from 40 to 99 weight percent of a) at least one ethylenically unsaturated nonionic monomer;

0.9 to 50 weight percent of b) at least one polymerizable ionic compound, wherein the polymerizable ionic compound comprises:

b1 At least one compound according to formula IV:

and/or

b2 At least one compound according to formula V):

wherein: r ⁷ Selected from: c ₁ -C ₃₀ An alkyl group; c ₂ -C ₈ An alkenyl group; c ₁ -C ₃₀ A heteroalkyl group; c _3- C ₃₀ A cycloalkyl group; c ₆ -C ₁₈ An aryl group; c ₁ -C ₉ A heteroaryl group; c _7- C ₁₈ An alkylaryl group; c _2- C ₅ A heterocycloalkyl group; or-R ^a -C(＝O)-R ^b In which

R ^a Is C ₁ -C ₆ Alkylene, and R ^b Is C ₁ -C ₆ An alkyl group;

R ⁹ is H or C ₁ -C ₄ An alkyl group;

each R ¹⁰ Independently selected from: c ₁ -C ₃₀ An alkyl group; c ₁ -C ₃₀ A heteroalkyl group; c _3- C ₃₀ A cycloalkyl group; c ₆ -C ₁₈ An aryl group;

C ₁ -C ₉ a heteroaryl group; c _7- C ₁₈ An alkylaryl group; c _2- C ₅ A heterocycloalkyl group; or-R ^a -C(＝O)-R ^b Wherein R is ^a Is C ₁ -C ₆ Alkylene, and R ^b Is C ₁ -C ₆ An alkyl group;

a is a non-polymerizable anion;

t is an ethylenically unsaturated anion;

d and m are each integers having a value of at least 1;

e and n have values such that the compound is electrically neutral; and is

Is a covalent bond, C ₁ -C ₂ Alkylene, -CH ₂ OC(＝O)-、-CH ₂ CH ₂ OC (= O) -, p-benzyl, or p-tolyl; and

0.1 to 10 wt.% of c) at least one free-radical initiator.

2. The adhesive composition of claim 1, comprising:

45 to 95 weight percent of a) the at least one ethylenically unsaturated nonionic monomer;

5 to 30 weight percent of b) the at least one polymerizable ionic compound;

0.1 to 5 wt.% of c) the at least one free radical initiator; and

0 to 10% by weight of d) a solubilizer.

3. The adhesive composition of claim 1 or claim 2, wherein part a) comprises 40 to 95 weight percent, based on the weight of the composition, of a 1) at least one (meth) acrylate monomer represented by formula I:

H ₂ C＝CGCO ₂ R ¹ (I)

wherein: g is hydrogen, halogen or C ₁ -C ₄ An alkyl group; and is

R ¹ Selected from: c ₁ -C ₃₀ An alkyl group; c ₂ -C ₃₀ A heteroalkyl group; c ₃ -C ₃₀ A cycloalkyl group; c ₂ -C ₈ A heterocycloalkyl group; c ₂ -C ₂₀ An alkenyl group; and C ₂ -C ₁₂ Alkynyl.

4. Adhesive composition according to any one of claims 1 to 3, wherein part a) comprises up to 50 wt. -%, preferably 5 to 25 wt. -%, based on the weight of the composition, of a 3) of at least one (meth) acrylate functionalized oligomer.

5. The adhesive composition according to any one of claims 1 to 4, wherein part a) comprises at least one α, β -ethylenically unsaturated monocarboxylic acid having 3 to 5 carbon atoms.

6. The adhesive composition according to any one of claims 1 to 5, wherein in part b):

R ⁷ is selected from C ₁ -C ₈ An alkyl group; c ₂ -C ₄ An alkenyl group; c ₁ -C ₈ A heteroalkyl group; c _3- C ₁₂ A cycloalkyl group; c ₆ -C ₁₈ An aryl group; c ₁ -C ₉ A heteroaryl group; c _7- C ₁₈ An alkylaryl group; c _2- C ₅ HeterocycloalkanesA group; or-R ^a -C(＝O)-R ^b Wherein R is ^a Is C ₁ -C ₄ Alkylene, and R ^b Is C ₁ -C ₄ An alkyl group;

each R ⁸ Preferably independently selected from H or C ₁ -C ₂ An alkyl group;

R ⁹ is H or methyl; and is

R ¹⁰ Is selected from C ₁ -C ₈ An alkyl group; c ₁ -C ₈ A heteroalkyl group; c _3- C ₁₂ A cycloalkyl group; c ₆ -C ₁₈ An aryl group; c ₁ -C ₉ A heteroaryl group; c _7- C ₁₈ An alkylaryl group; c _2- C ₅ A heterocycloalkyl group; or-R ^a -C(＝O)-R ^b Wherein R is ^a Is C ₁ -C ₄ Alkylene, and R ^b Is C ₁ -C ₄ An alkyl group.

7. The adhesive composition according to any one of claims 1 to 5, wherein part b) comprises:

b1 At least one compound selected from the group consisting of: 3-vinyl-1-methyl-1H-imidazolium iodide; 3-vinyl-1-methyl-1H-imidazolium chloride; 3-vinyl-1-methyl-1H-imidazolium bromide; 3-vinyl-1-methyl-1H-imidazolium methanesulfonate; 3-vinyl-1-methyl-1H-imidazolium 1,1,1-trifluoro-N- [ (trifluoromethyl) sulfonyl ] methanesulfonamide; 3-vinyl-1-ethyl-1H-imidazolium 1,1,1-trifluoro-N- [ (trifluoromethyl) sulfonyl ] methanesulfonamide; 3-vinyl-1-methyl-1H-imidazolium hexafluorophosphate; 3-vinyl-1-methyl-1H-imidazolium 4-methylbenzenesulfonate; 3-vinyl-1-methyl-1H-imidazolium tetrafluoroborate; 3-vinyl-1-ethyl-1H-imidazolium iodide; 3-vinyl-1-ethyl-1H-imidazolium bromide; 3-vinyl-1-ethyl-1H-imidazolium 1,1,1-trifluoro-N- [ (trifluoromethyl) sulfonyl ] methanesulfonamide; 3-vinyl-1-ethyl-1H-imidazolium hexafluorophosphate; 3-vinyl-1-ethyl-1H-imidazolium tetrafluoroborate; 3-vinyl-1- (1-methylethyl) -1H-imidazolium bromide; 3- (1,1-dimethylethyl) -1-vinyl-1H-imidazolium bromide; 3-vinyl-1-propyl-1H-imidazolium bromide; 3-vinyl-1- (phenylmethyl) -1H-imidazolium bromide; 1-vinyl-3- (4-methylphenyl) -1H-imidazolium chloride; 3-vinyl-1- (1-methylpropyl) -1H-imidazolium chloride; 1-butyl-3-vinyl-1H-imidazolium bromide; 3- [ (4-vinylphenyl) methyl ] -1-methyl-iodide; 3- [ (4-vinylphenyl) methyl ] -1-methyl-1H-imidazolium chloride; 3- [ (4-vinylphenyl) methyl ] -1-methyl-1H-imidazolium 1,1,1-trifluoro-N- [ (trifluoromethyl) sulfonyl ] methanesulfonamide; 3- [ (4-vinylphenyl) methyl ] -1-methyl-1H-imidazolium hexafluorophosphate; 3- [ (4-vinylphenyl) methyl ] -1-methyl-1H-imidazolium tetrafluoroborate; 3- [ (4-vinylphenyl) methyl ] -1-ethyl-1H-imidazolium chloride; salts of 1- [ (4-vinylphenyl) methyl ] -3-ethyl-1H-imidazolium with 1,1,1-trifluoro-N- [ (trifluoromethyl) sulfonyl ] methanesulfonamide; 1- (3-aminopropyl) -3- [ (4-vinylphenyl) methyl ] -1H-imidazolium chloride; 1-butyl-3- [ (4-vinylphenyl) methyl ] -1H-imidazolium chloride; and/or

b2 At least one compound selected from the group consisting of: 1-methyl-3-hexyl-1H-imidazolium 4-vinylbenzenesulfonate; 1-dodecyl-3-vinyl-1H-imidazolium 4-vinylbenzenesulfonate; 1-methyl-3-propyl-1H-imidazolium 4-vinylbenzenesulfonate; and 3-ethyl-1-methyl-1H-imidazolium 4- (1-methylvinyl) benzenesulfonate.

8. The adhesive composition according to any one of claims 1 to 5, wherein part b) comprises at least one compound selected from the group consisting of: 3-methyl-1-hexyl-1H-imidazolium 4-vinylbenzenesulfonate; 3-vinyl-1-ethyl-1H-imidazolium 1,1,1-trifluoro-N- [ (trifluoromethyl) sulfonyl ] methanesulfonamide; and 3-methyl-1-butyl-1H-imidazolium 1,1,1-trifluoro-N- [ (trifluoromethyl) sulfonyl ] methanesulfonamide.

9. The adhesive composition according to any one of claims 1 to 8, wherein part c) comprises at least one azo free radical initiator selected from the group consisting of: azonitriles; azo esters; azoamides; azoamidines; azoimidazoline; and a macroazo initiator.

10. The adhesive composition according to any one of claims 1 to 9, wherein the composition comprises d) a solubilizer in an amount of up to 10% by weight, based on the weight of the composition, and the solubilizer is selected from the group consisting of: a polyoxyalkylene glycol; a silicone surfactant; a polyol; and a saccharide.

11. The adhesive composition of any one of claims 1 to 10, wherein the composition comprises conductive particles in an amount of up to 10 wt.%, based on the weight of the composition.

12. The adhesive composition of claim 11 wherein the conductive particles are selected from the group consisting of silver, carbon black, and mixtures thereof.

13. A bonded structure, the bonded structure comprising:

a first layer of material having a conductive surface; and

a second layer of material having a conductive surface;

wherein the curable and electrochemically debondable adhesive composition according to any one of claims 1 to 12 is disposed between the first material layer and the second material layer.

14. A method of debonding the bonded structure of claim 13, the method comprising the steps of:

1) Applying a voltage across the two surfaces to form an anode interface and a cathode interface; and

2) Debonding the surface.

15. The method according to claim 14, wherein the voltage applied in step 1 is 0.5 to 200V, and preferably applied for a duration of 1 second to 30 minutes.