One-component (1K) curable adhesive composition

Abstract

The present disclosure provides: a) at least one epoxide compound; b) a curing agent consisting of one or more compounds having at least one epoxide reactive group and no disulfide functionality; c) a repair agent comprising one or more compounds containing at least one disulfide functional group and, optionally, at least one epoxide-reactive group selected from hydroxyl; thiol; amine; or carboxyl; and d) electrolytes A curable, electrochemically releasable one-component (1K) adhesive composition comprising: The composition relates to an adhesive composition characterized by a molar ratio of epoxide-reactive groups to epoxide groups of 0.6:1 to 1.2:1.

Description

[Technical Field]

[0001] The present invention relates to one-component (1K) curable adhesive compositions that, after curing, are capable of bonding substrates together and withstanding loads in bonded composite structures, but are also capable of being electrochemically debonded from the particular substrate to which they are applied. More specifically, the present invention relates to one-component (1K) curable, electrochemically debondable adhesive compositions that at least partially regain their ability to bond substrates together and withstand loads in bonded composite structures after an electrochemical debonding operation. [Background technology]

[0002] Adhesive bonds and polymer coatings are commonly used in the assembly and finishing of manufactured products. They replace mechanical fasteners such as screws, bolts, and rivets, reducing processing costs and providing highly adaptable bonds in manufacturing processes. Adhesive bonds distribute stress evenly, reducing the potential for fatigue and sealing the joint from corrosive species.

[0003] Thus, while adhesives offer many advantages over mechanical fasteners, certain drawbacks must be acknowledged. First, adhesively bonded objects tend to be difficult to disassemble when required for practical applications. Second, when an adhesive cures in situ to bond two substrates, a cross-linked chemical network is formed: after disassembly of the bonded objects, that chemical network cannot, in most cases, be reused as an adhesive. These drawbacks are particularly evident in industries (often resource-intensive) where it is beneficial to recycle, reuse, or repurpose manufactured goods.

[0004] The first drawback identified is that removing the adhesive by mechanical processes such as sandblasting or wire brushing is often impossible because the adhesive is located between the substrates and is therefore inaccessible, or because it is difficult to remove the adhesive without destroying the substrate surface. Decomposition by application of chemicals and / or high temperatures, as disclosed in U.S. Pat. No. 4,171,240 (Wong), U.S. Pat. No. 4,729,797 (Linde et al.), and U.S. Patent Application Publication No. 20140287299 (Krogdahl), may be effective, but can be time-consuming and complicated to implement, especially when protecting the substrate surface on which the adhesive remains: the aggressive chemicals and / or the harsh conditions required can remove substantially all of the adhesive, damaging the separated substrates and rendering them unsuitable for subsequent use.

[0005] As an illustrative example, it is clearly desirable to remove, replace, or recycle adhesively attached components in electronic devices such as laptops and cell phones. However, these adhesives are designed and typically strong to maintain adhesion during drop or impact events, and over a wide range of operating temperatures and other environmental conditions. If care is not taken, adhesively bonded device components can be damaged or destroyed when removing the components through mechanical processing, chemicals, or the application of high temperatures.

[0006] In response to these problems, some authors have attempted to develop releasable adhesive compositions that act by passing an electric current through the cured composition, thereby disrupting the bond at the adhesive / substrate interface.

[0007] U.S. Pat. No. 7,465,492 (Gilbert) describes a strippable composition comprising a matrix functional group comprising a monomer selected from the group consisting of acrylic, methacrylic, and combinations thereof; a free radical initiator; and an electrolyte, wherein the electrolyte provides the composition with sufficient ionic conductivity to support a Faradaic reaction in the bond formed between the composition and a conductive surface, thereby enabling the composition to be stripped from the surface.

[0008] U.S. Patent Application Publication No. 2007 / 0269659 (Gilbert) describes a two-interface releasable adhesive composition that (i) comprises a polymer and an electrolyte; (ii) promotes bonding of two surfaces; and (iii) releases from both the anode and cathode surfaces in response to a voltage applied to both surfaces to form an anode interface and a cathode interface.

[0009] US Patent Application Publication No. 2008 / 0196828 (Gilbert) describes a hot melt adhesive composition comprising a thermoplastic component; and an electrolyte that provides the composition with sufficient ionic conductivity to enable a faradaic reaction at the bond formed between the composition and a conductive surface, thereby enabling the composition to be released from the surface.

[0010] WO 2017 / 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 a surface of the non-conductive substrate with a conductive ink; b) applying an electrically releasable hot melt adhesive composition to the conductive ink-coated surface of the first substrate and / or the second substrate; c) contacting the first substrate and the second substrate such that the electrically releasable hot melt adhesive composition is interposed between the two substrates; d) forming an adhesive bond between the two substrates to provide an adhesive substrate; and e) applying a voltage to the adhesive substrate, whereby at least one interfacial adhesion between the electrically releasable hot melt adhesive composition and the substrate surface is substantially weakened.

[0011] WO 2021 / 115771 (Henkel AG & Co. KGaA) relates to a curable one-component (1K) peelable adhesive composition comprising: a) an epoxy resin; b) a hardener for the epoxy resin; c) an electrolyte; and d) a non-conductive filler; wherein the composition also comprises at least one of: e) a combination of a solubilizer and a toughening agent; and f) conductive particles. [Prior art documents] [Patent documents]

[0012] [Patent Document 1] U.S. Patent No. 4,171,240 [Patent Document 2] U.S. Patent No. 4,729,797 [Patent Document 3] US Patent Application Publication No. 2014 / 0287299 [Patent Document 4] U.S. Patent No. 7,465,492 [Patent Document 5] US Patent Application Publication No. 2007 / 0269659 [Patent Document 6] US Patent Application Publication No. 2008 / 0196828 [Patent Document 7] International Application Publication No. 2017 / 133864 [Patent Document 8] International Application Publication No. 2021 / 115771 Summary of the Invention [Problem to be solved by the invention]

[0013] Despite the advantageous development of electrochemically releasable adhesive compositions, none of the above cited documents provide for the reuse of the released adhesive to form composite structures.Therefore, it is believed that there is a need in the art to provide an adhesive composition that can be conveniently applied to the surface of the substrate to be bonded, that upon curing provides effective adhesion within a composite structure including the substrate, and that can be efficiently peeled from the substrate by simply applying an electric potential to the cured adhesive, and that also allows for the reuse of the cured adhesive in effectively bonding the substrates.Such releasable adhesives are particularly useful in electronic devices. [Means for solving the problem]

[0014] According to a first aspect of the present invention, a) at least one epoxide compound; b) a curing agent consisting of one or more compounds having at least one epoxide reactive group and no disulfide functionality; c) a repair agent consisting of one or more compounds containing at least one disulfide functional group and optionally at least one epoxide-reactive group selected from hydroxyl; thiol; amine; or carboxyl; and d) electrolytes A curable, electrochemically releasable one-component (1K) adhesive composition comprising: An adhesive composition is provided, wherein the composition is characterized by a molar ratio of epoxide-reactive groups to epoxide groups of 0.6:1 to 1.2:1.

[0015] In an important embodiment of the present invention, the composition comprises, based on the weight of the composition: 15 to 50 wt. %, preferably 20 to 50 wt. %, more preferably 20 to 40 wt. % of a) at least one polyepoxide compound; 0.01 to 25 wt. %, preferably 5 to 25 wt. %, more preferably 5 to 20 wt. % of b) a curing agent consisting of one or more compounds having at least two epoxide-reactive groups and no disulfide functionality; 0.01 to 10% by weight, preferably 1 to 10% by weight, more preferably 2 to 8% by weight of c) said restorative; 0.5 to 15 wt %, preferably 0.5 to 10 wt %, more preferably 0.5 to 5 wt % of d) the electrolyte; and 0 to 55 wt. %, preferably 1 to 55 wt. %, more preferably 15 to 55 wt. % of e) a rheology control agent; Including, The composition is characterized by a molar ratio of epoxide-reactive groups to epoxide groups of 0.6:1 to 1.1:1, preferably 0.75:1 to 1:1, more preferably 0.75:1 to 0.95:1. The polyepoxide compound of the composition is preferably selected from the group consisting of bisphenol A epoxy resins, bisphenol F epoxy resins, and mixtures thereof.

[0016] Compositions conforming to these definitions have been shown to provide excellent adhesive stability even under high temperature and humidity conditions. The following examples demonstrate stability, inter alia, at 95% relative humidity (RH) and 65°C. Furthermore, when the cured adhesive compositions were used to form composite structures, these structures were easily peeled by applying a potential difference across the adhesive bond.

[0017] The presence of the healing agent allows the cured composition of the present disclosure to be reused to form bonded structures after the initial composite structure has been subjected to an electrochemical peeling operation. It is believed that, under thermal activation, disulfide rearrangement occurs within the cured matrix. The resulting change in the topology of the matrix of the previously cured and peeled adhesive allows the adhesive to bond substrates together. The following examples demonstrate that the adhesive strength after thermal activation is significantly restored to that of the initially cured adhesive composition.

[0018] b) Preferably, the curing agent of the composition comprises or consists of a thiol-functional compound selected from the group consisting of pentaerythritol tetramercaptoacetate (PETMP), tris-(3-mercaptopropionate) (TMP), trimethylolpropane trimercaptoacetate (TMPMP), tris(2-(mercaptopropionyloxy)ethyl)isocyanate, glycol dimercaptoacetate, and mixtures thereof.

[0019] In one embodiment, the repair agent comprises a compound selected from the group consisting of bis(4-aminophenyl)disulfide; bis(2-aminophenyl)disulfide; 2-amino-4-chlorophenyl disulfide; and mixtures thereof. In an alternative embodiment, the repair agent comprises a compound selected from the group consisting of 3,3'-dithiopropionic acid; 4,4'-dithiobutyric acid; bis-(10-carboxydecyl)disulfide; 2,2'-dithiobisethanamine (cystamine); (2R)-2-amino-3-[[(2R)-2-amino-2-carboxyethyl]disulfanyl]propanoic acid (L-cystine); and mixtures thereof. In a further alternative embodiment, the repair agent comprises a liquid mercaptan-terminated polysulfide polymer.

[0020] Regardless of or in addition to this description of the preferences for the curing agent and the healing agent, it is preferred that the electrolyte is selected from the group consisting of: 1-ethyl-3-methyl-1H-imidazol-3-ium methanesulfonate; 1-ethyl-3-methyl-1H-imidazol-3-ium methylsulfate; 1-methylimidazolium bis(trifluoromethylsulfonyl)imide; 3-methylimidazolium bis(trifluoromethylsulfonyl)imide; 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide; 1-propyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide; 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide; 1-butyl-2,3-dimethylimidazolium bis(trifluoromethylsulfonyl)imide; 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide; 1-octyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide. imidazolium bis(trifluoromethylsulfonyl)imide; 1-methyl-3-octylimidazolium bis(trifluoromethylsulfonyl)imide; 1-decyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide; 1-dodecyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide; tetraethylphosphonium bis(trifluoromethylsulfonyl)imide; tetrabutylphosphonium bis(trifluoromethylsulfonyl)imide; tetraoctylphosphonium bis(trifluoromethylsulfonyl)imide; trihexyl(tetradecyl)phosphonium bis(trifluoromethylsulfonyl)imide; tridecyl(tetradecyl)phosphonium bis(trifluoromethylsulfonyl)imide; tributyl(methyl)phosphonium diethyl phosphate; tributyl(ethyl)phosphonium diethyl phosphate; tetraoctylphosphonium diethyl phosphate; and mixtures thereof.It may be mentioned that the electrolytes selected from the group consisting of 1-ethyl-3-methyl-1H-imidazol-3-ium methanesulfonate; 1-ethyl-3-methyl-1H-imidazol-3-ium methylsulfate; trihexyl(tetradecyl)phosphonium bis(trifluoromethylsulfonyl)imide; tributyl(methyl)phosphonium diethylphosphate; tributyl(ethyl)phosphonium diethylphosphate; and mixtures thereof are particularly preferred.

[0021] According to a second aspect of the present invention, a first substrate having a conductive surface; and a second substrate having a conductive surface An adhesive structure comprising: An adhesive structure is provided in which the cured adhesive composition as described hereinabove and defined in the appended claims is disposed between the first and second substrates.

[0022] The present disclosure also provides the use of a cured composition as described hereinabove and defined in the appended claims as an adhesive, wherein use of the previously cured composition is preceded by a heat treatment of the cured composition to activate rearrangement of disulfide bonds therein.

[0023] In accordance with a further aspect of the present invention, there is provided a method of forming and reforming an adhesive structure, the method comprising: a first substrate having a conductive surface; a second substrate having a conductive surface; and a cured adhesive composition as hereinbefore described and defined in the appended claims disposed between said first and second substrates. providing a first adhesive structure comprising: applying a voltage to both conductive surfaces to form an anodic interface and a cathodic interface; peeling the first and second substrates apart; contacting the peeled first substrate with a third substrate such that the cured adhesive composition is interposed between the first substrate and the third substrate; and heat treating the residual cured adhesive composition to bond the first and third substrates together. Includes. [Brief explanation of the drawings]

[0024] [Figure 1a] FIG. 1a shows a bonded structure according to a first embodiment of the present invention. [Figure 1b] FIG. 1b shows a bonded structure according to a second embodiment of the invention. [Figure 2a] FIG. 2a shows the initial delamination of the structure of the first embodiment when current is applied to the structure. [Figure 2b] FIG. 2b shows the initial delamination of the structure of the second embodiment when current is applied to the structure. [Figure 3a] FIG. 3a shows a reconfiguration of the adhesive structure according to a first embodiment of the invention. [Figure 3b] FIG. 3b shows a reconfiguration of the adhesive structure according to a second embodiment of the invention. [Figure 3c] FIG. 3c shows a reconfiguration of the adhesive structure according to a third embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0025] [Definition] As used herein, the singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise.

[0026] As used herein, the terms "comprising," "comprises," and "comprised of" are synonymous with "including," "includes," "containing," or "contains," and are inclusive or open-ended and do not exclude additional, unrecited members, elements, or method steps.

[0027] As used herein, the term "consisting of" excludes any elements, components, materials, or method steps not specified.

[0028] When amounts, concentrations, dimensions, and other parameters are expressed in the form of ranges, preferred ranges, upper values, lower values, or preferred upper and lower values, it is to be understood that any range obtained by combining any upper value or preferred value with any lower value or preferred value is also specifically disclosed, whether or not the resulting range is expressly stated in the context.

[0029] Also, in accordance with standard understanding, weight ranges expressed as "from 0 to x" specifically include 0% by weight: the component defined by said range may be absent from the composition or may be present in the composition in an amount up to x% by weight.

[0030] The words "preferred," "preferably," "desirably," and "particularly" are frequently used herein to refer to embodiments of the present disclosure that may provide particular benefits, under particular circumstances. However, the recitation of one or more preferred, preferred, desirable, or particular embodiments does not imply that other embodiments are not useful, and is not intended to exclude such other embodiments from the scope of the present disclosure.

[0031] The word "exemplary" is used herein to mean serving as an example, instance, or illustration. Any aspect or design described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other aspects or designs. Rather, use of the word exemplary is intended to present concepts in a concrete manner.

[0032] The word "may" as used throughout this application is used in a permissive, i.e., possible, rather than mandatory, sense.

[0033] As used herein, room temperature is 23° C. plus or minus 2° C. As used herein, "ambient conditions" means the ambient temperature and pressure in which the composition is located, or in which the coating layer or substrate for said coating layer is located.

[0034] As used herein, the term "peelable" means that after the adhesive has cured, the adhesive strength can be weakened by at least 50% by applying a potential of 0.5 V to 100 V for 1 second to 60 minutes. The cured adhesive is applied between two adhesively bonded substrates such that a current flows through the adhesive bond line. The adhesive strength is measured by a Tensile Lap Shear (TLS) test of the adhesive assembly according to EN 1465:2009 (German edition), performed at room temperature.

[0035] As used herein, the term "monomer" refers to a substance that can undergo a polymerization reaction to provide a building block for the chemical structure of a polymer. As used herein, the term "monofunctional" means having one polymerizable moiety. As used herein, the term "multifunctional" means having multiple polymerizable moieties.

[0036] As used herein, the term "equivalents (eq.)" refers, as is usual in chemical notation, to the relative number of reactive groups present in a reaction.

[0037] The term "electrolyte" is used herein in accordance with its standard meaning in the art as a material containing free ions capable of conducting electricity by displacement of charge carrier species. The term is intended to encompass molten, liquid, semi-solid, and solid electrolytes in which at least one of the cationic or anionic components of the electrolyte structure is essentially free to move and thus act as a charge carrier.

[0038] The curable adhesive compositions of the present invention and the resulting cured adhesives have "electrolyte functionality" in that the adhesive material allows for the conduction of ions, either anions, cations, or both. Electrolyte functionality is understood to result from the ability of the compositions and cured adhesives to solvate ions of at least one polarity.

[0039] As used herein, "(meth)acryl" is a shorthand term referring to "acryl" and / or "methacryl." Thus, the term "(meth)acrylamide" is a general term for acrylamide and methacrylamide.

[0040] As used herein, "C1-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. 18 An "alkyl" group refers to a monovalent group containing 1 to 18 carbon atoms, which is a radical of an alkane, including straight-chain and branched organic groups. Generally, alkyl groups containing 1 to 12 carbon atoms (C1-C 12 It should be mentioned that alkyl groups, such as alkyl groups containing 1 to 8 carbon atoms (C1-C8 alkyl), are preferred. Examples of alkyl groups include, but are not limited to, methyl; ethyl; propyl; isopropyl; n-butyl; isobutyl; sec-butyl; tert-butyl; n-pentyl; n-hexyl; n-heptyl; and 2-ethylhexyl. In the present invention, such alkyl groups may be unsubstituted or substituted with one or more halogens. If applicable to a given moiety (R), the tolerance for one or more non-halogen substituents in an alkyl group is described in the specification.

[0041] As used herein, "C1-C 18 The term "hydroxyalkyl" refers to a HO-(alkyl) group having from 1 to 18 carbon atoms, where the point of attachment of the substituent is through the oxygen atom and the alkyl group is as defined above.

[0042] "Alkoxy" refers to a monovalent group represented by -OA, where A is an alkyl group. Non-limiting examples include methoxy, ethoxy, and isopropyloxy. As used herein, "C-C 18 The term "alkoxyalkyl" refers to an alkyl group having an alkoxy substituent, as defined above, where the portion (alkyl-O-alkyl) contains a total of 1 to 18 carbon atoms. Such groups include methoxymethyl (-CHOCH), 2-methoxyethyl (-CHCHOCH), and 2-ethoxyethyl. Similarly, as used herein, "C-C 18 The term "alkoxyaryl" refers to an aryl group having an alkoxy substituent, as defined above, where the moiety (aryl-O-alkyl) contains from 7 to 18 total carbon atoms.

[0043] The term "C2-C4 alkylene," as used herein, is defined as a saturated divalent hydrocarbon radical having from two to four carbon atoms.

[0044] "C3-C 18 The term "cycloalkyl" is understood to mean a saturated, monocyclic or polycyclic hydrocarbon group having 3 to 18 carbon atoms. In the present invention, such cycloalkyl groups may be unsubstituted or substituted with one or more halogens. If applicable to a given moiety (R), the tolerance of one or more non-halogen substituents in a cycloalkyl group is described in the specification. Examples of cycloalkyl groups include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, adamantane, and norbornane.

[0045] As used herein, "C6-C 18The term "aryl" used alone or as part of a larger moiety, as in "aralkyl," refers to monocyclic, bicyclic, and tricyclic ring systems in which the monocyclic ring system is aromatic, or in which at least one ring of the bicyclic or tricyclic ring system is aromatic. Bicyclic and tricyclic ring systems include benzo-fused 2- to 3-membered carbocyclic rings. In the present invention, such aryl groups can be unsubstituted or substituted with one or more halogens. If applicable to a given moiety (R), the allowance for one or more non-halogen substituents in an aryl group is described in the specification. Exemplary aryl groups include (C1-C4) alkylphenyl such as phenyl, tolyl, and ethylphenyl, indenyl, naphthalenyl, tetrahydronaphthyl, tetrahydroindenyl, tetrahydroanthracenyl, and anthracenyl. It can be noted that the phenyl group is preferred.

[0046] As used herein, "C2-C 20 "Alkenyl" refers to a hydrocarbyl group having 2 to 20 carbon atoms and at least one unit of ethylenic unsaturation. Alkenyl groups may be straight-chained, branched, or cyclic, and may optionally be substituted with one or more halogens. If applicable to a given moiety (R), the permissible range of one or more non-halogen substituents in an alkenyl group is described in the specification. The term "alkenyl" also encompasses groups having "cis" and "trans" configurations, or alternatively, "E" and "Z" configurations, as understood by those skilled in the art. However, generally, alkenyl groups having 2 to 10 (C 2-10 ) or 2 to 8 pieces (C 2~8 It should be noted that unsubstituted alkenyl groups containing carbon atoms of C2-C are preferred. 12Examples of alkenyl groups include, but are not limited to, -CH=CH2; -CH=CHCH3; -CH2CH=CH2; -C(=CH2)(CH3); -CH=CHCH2CH3; -CH2CH=CHCH3; -CH2CH2CH=CH2; -CH=C(CH3)2; -CH2C(=CH2)(CH3); -C(=CH2)CH2CH3; -C(CH3)=CHCH3; -C(CH3)CH=CH2; -CH=CHCH2CH2CH3; -CH2CH=CHC H2CH3;-CH2CH2CH=CHCH3;-CH2CH2CH2CH=CH2;-C(=CH2)CH2CH2CH3;-C(CH3)=CHCH2CH3;-CH(CH3)CH=CHCH;-CH(CH3)CH=CHCH;-CH(CH3)CH2CH=CH2;-CH2CH=C(CH3)2;1-cyclopent-1-enyl;1-cyclopent-2-enyl;1-cyclopent-3-enyl;1-cyclohex-1-enyl;1-cyclohex-2-enyl; and1-cyclohex-3-enyl.

[0047] As used herein, "alkylaryl" refers to an alkyl-substituted aryl group, both of which are as defined above. Additionally, as used herein, "aralkyl" refers to an alkyl group substituted with an aryl radical, as defined above.

[0048] The term "hetero," as used herein, refers to groups or moieties that include one or more heteroatoms, such as N, O, Si, and S. Thus, for example, "heterocyclic" refers to cyclic groups having, for example, N, O, Si, or S as part of the ring structure. "Heteroalkyl," "heterocycloalkyl," and "heteroaryl" moieties are alkyl, cycloalkyl, and aryl groups, respectively, that include N, O, Si, or S as part of their structure, as defined hereinabove.

[0049] As used herein, the term "equivalent weight" refers to the molecular weight divided by the valence, so "epoxy equivalent weight" (EEW) means the weight (grams) of a resin containing one equivalent of epoxy.

[0050] As used herein, the term "epoxide" refers to a compound characterized by the presence of at least one cyclic ether group, i.e., a compound in which an ether oxygen atom is bonded to two adjacent carbon atoms, thereby forming a cyclic structure. The term is intended to encompass monoepoxide compounds, polyepoxide compounds (having two or more epoxide groups), and epoxide-terminated prepolymers. The term "monoepoxide compound" refers to an epoxide compound having one epoxy group. The term "polyepoxide compound" refers to an epoxide compound having at least two epoxy groups. The term "diepoxide compound" refers to an epoxide compound having two epoxy groups.

[0051] The epoxide may be unsubstituted or may be inertly substituted. Exemplary inert substituents include chlorine, bromine, fluorine, and phenyl.

[0052] As used herein, the term "disulfide group" refers to a functional group having the structure RSS-R'. For a compound to be referred to as a disulfide, the compound must have a -SS- bond.

[0053] Molecular weights as referred to herein can be determined by gel permeation chromatography (GPC), such as performed in accordance with ASTM 3536, using polystyrene calibration standards.

[0054] As used herein, the term softening point (°C) used herein in reference to waxes is the ring and ball softening point unless otherwise specified, and is measured in accordance with ASTM E28.

[0055] The viscosity of the compositions described herein is measured using an Anton Paar Viscometer, Model MCR 301, at standard conditions of 25°C and 50% relative humidity (RH), unless otherwise specified. The viscometer is calibrated annually and serviced. Calibration is performed using known standards with viscosities between 1 and 50,000 cps (parallel plate PP20, shear rate 1 s). -1 The composition of the present invention is measured using a parallel plate PP20 at 1.5 to 100 s. -1 The process is carried out at different shear rates.

[0056] Detailed Description of the Invention [a) Epoxide Compounds] The composition of the present disclosure necessarily contains at least one epoxide compound. Typically, the composition contains 15 to 50 wt. % of a) said at least one epoxide, based on the weight of the composition. Preferably, the total amount of epoxide compounds is 20 to 50 wt. %, for example, 20 to 40 wt. % of the composition.

[0057] The epoxide compounds used herein can include monofunctional epoxide compounds, polyfunctional or multifunctional epoxide compounds, and combinations thereof. Part a) of the composition can be composed of a single epoxide compound, but can also be a mixture of epoxide-functional compounds, such as a mixture of compounds having different numbers of epoxide groups per molecule. The epoxide compounds can be saturated or unsaturated, aliphatic, cycloaliphatic, aromatic, or heterocyclic, and can be substituted. Furthermore, the epoxide compounds can be monomeric or polymeric.

[0058] While not intending to limit the invention, exemplary monoepoxide compounds include: alkylene oxides; epoxy-substituted cycloaliphatic hydrocarbons, such as cyclohexene oxide, vinylcyclohexene monoxide, (+)-cis limonene oxide, (+)-cis, trans-limonene oxide, (-)-cis, trans-limonene oxide, cyclooctene oxide, cyclododecene oxide, and α-pinene oxide; epoxy-substituted aromatic hydrocarbons; monoepoxy-substituted alkyl ethers of monohydric alcohols or phenols, such as glycidyl ethers of aliphatic, cycloaliphatic, and aromatic alcohols. monoepoxy-substituted alkyl esters of monocarboxylic acids, such as the glycidyl esters of aliphatic, cycloaliphatic, and aromatic monocarboxylic acids; monoepoxy-substituted alkyl esters of polycarboxylic acids in which the other carboxy group has been esterified with an alkanol; alkyl and alkenyl esters of epoxy-substituted monocarboxylic acids; epoxy alkyl ethers of polyhydric alcohols in which the other OH group has been esterified or etherified with a carboxylic acid or alcohol; and monoesters of epoxy monocarboxylic acids with polyhydric alcohols in which the other OH group has been esterified or etherified with a carboxylic acid or alcohol.

[0059] By way of example, monoepoxide compounds particularly suitable for use herein may include the following glycidyl ethers: methyl glycidyl ether, ethyl glycidyl ether, propyl glycidyl ether, butyl glycidyl ether, pentyl glycidyl ether, hexyl glycidyl ether, cyclohexyl glycidyl ether, octyl glycidyl ether, 2-ethylhexyl glycidyl ether, allyl glycidyl ether, benzyl glycidyl ether, phenyl glycidyl ether, 4-tert-butylphenyl glycidyl ether, 1-naphthyl glycidyl ether, 2-naphthyl glycidyl ether, 2-chlorophenyl glycidyl ether, 4-chlorophenyl glycidyl ether, 4-bromophenyl glycidyl ether, 2,4,6-trichlorophenyl glycidyl ether, 2,4,6-tribromophenyl glycidyl ether, pentafluorophenyl glycidyl ether, o-cresyl glycidyl ether, m-cresyl glycidyl ether, and p-cresyl glycidyl ether.

[0060] In one embodiment, the monoepoxide compound conforms to formula (E) herein: [ka] (In the formula, R w , R x , R y and R z may be the same or different and independently represent hydrogen, a halogen atom, a C1-C8 alkyl group, a C3-C 10 Cycloalkyl groups, C2-C 12 Alkenyl, C6-C 18 Aryl group or C7-C 18 aralkyl groups, provided that R y and R z At least one of them is not hydrogen.)

[0061] R w , R x and R y is hydrogen and R zis preferably a phenyl group or a C1-C8 alkyl group, more preferably a C1-C4 alkyl group.

[0062] For this embodiment, exemplary monoepoxides include ethylene oxide, 1,2-propylene oxide (propylene oxide), 1,2-butylene oxide, cis-2,3-epoxybutane, trans-2,3-epoxybutane, 1,2-epoxypentane, 1,2-epoxyhexane, 1,2-heptylene oxide, decene oxide, butadiene oxide, isoprene oxide, and styrene oxide.

[0063] The present invention refers to the use of at least one monoepoxide compound selected from the group consisting of ethylene oxide, propylene oxide, cyclohexene oxide, (+)-cis limonene oxide, (+)-cis, trans-limonene oxide, (-)-cis, trans-limonene oxide, cyclooctene oxide, and cyclododecene oxide.

[0064] Although not intended to limit the scope of the present invention, suitable polyepoxide compounds may be liquid, solid, or in solution in a solvent. Furthermore, such polyepoxide compounds should have an epoxide equivalent weight of 100 to 700 g / eq, e.g., 120 to 320 g / eq. Generally, diepoxide compounds having an epoxide equivalent weight of less than 500 g / eq or even less than 400 g / eq are preferred. This is primarily because, from a cost perspective, lower molecular weight epoxy resins require more extensive purification treatment during production.

[0065] Examples of classes or groups of polyepoxide compounds that can be polymerized in the present invention include glycidyl ethers of polyhydric alcohols and polyhydric phenols; glycidyl esters of polycarboxylic acids; and epoxidized polyethylenically unsaturated hydrocarbons, esters, ethers, and amides.

[0066] Suitable diglycidyl ether compounds may be aromatic, aliphatic, or cycloaliphatic in nature and may therefore be derived from dihydric phenols and dihydric alcohols. Useful classes of such diglycidyl ethers include: diglycidyl ethers of aliphatic and cycloaliphatic diols, such as 1,2-ethanediol, 1,4-butanediol, 1,6-hexanediol, 1,8-octanediol, 1,12-dodecanediol, cyclopentanediol, and cyclohexanediol; bisphenol A-based diglycidyl ethers; bisphenol F diglycidyl ethers; diglycidyl o-phthalate, diglycidyl isophthalate, and diglycidyl terephthalate; polyalkylene glycol-based diglycidyl ethers, particularly polypropylene glycol diglycidyl ethers; and polycarbonate diol-based glycidyl ethers. Other suitable diepoxides that may be mentioned include diunsaturated fatty acid C1-C2 diglycidyl ethers. 18 Included are diepoxides of alkyl esters; butadiene diepoxide; polybutadiene diglycidyl ether; vinylcyclohexene diepoxide; and limonene diepoxide.

[0067] Further exemplary polyepoxide compounds include, but are not limited to, glycerol polyglycidyl ether, trimethylolpropane polyglycidyl ether, pentaerythritol polyglycidyl ether, diglycerol polyglycidyl ether, polyglycerol polyglycidyl ether, and sorbitol polyglycidyl ether.

[0068] Examples of highly preferred polyepoxide compounds include bisphenol A epoxy resins such as DER™ 331, DER™ 330, DER™ 337, and DER™ 383; bisphenol F epoxy resins such as DER™ 354; bisphenol A / F epoxy resin blends such as DER™ 353; aliphatic glycidyl ethers such as DER™ 736; polypropylene glycol diglycidyl ethers such as DER™ 732; solid bisphenol A epoxy resins such as DER™ 661 and DER™ 664 UE; solutions of bisphenol A solid epoxy resins such as DER™ 671-X75; epoxy novolac resins such as DEN™ 438; brominated epoxy resins such as DER™ 542; castor oil triglycidyl ethers such as ERISYS™ GE-35 H, etc.; polyglycerol-3-polyglycidyl ethers, such as ERISYS™ GE-38; and sorbitol glycidyl ethers, such as ERISYS™ GE-60.

[0069] Notwithstanding the above, in certain embodiments, the composition comprises a compound of the formula: [ka] wherein each R is independently selected from methyl or ethyl; (n is 1 to 10) The glycidoxyalkylalkoxysilane may include a glycidoxyalkylalkoxysilane having the formula:

[0070] Exemplary silanes include, but are not limited to, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxyethyltrimethoxysilane, γ-glycidoxymethyltrimethoxysilane, γ-glycidoxymethyltriethoxysilane, γ-glycidoxyethyltriethoxysilane, γ-glycidoxypropyltriethoxysilane, and 8-glycidoxyoctyltrimethoxysilane. If present, the epoxide-functional silane should constitute less than 20 wt. %, preferably less than 10 wt. % or less than 5 wt. %, based on the total weight of the epoxide compounds.

[0071] The present invention also does not exclude that the curable composition further comprises one or more cyclic monomers selected from the group consisting of oxetanes, cyclic carbonates, cyclic anhydrides, and lactones. The disclosures of the following references may be useful in disclosing suitable cyclic carbonate-functional compounds: U.S. Pat. No. 3,535,342, U.S. Pat. No. 4,835,289, U.S. Pat. No. 4,892,954, GB 1,485,925, and EP 0,119,840. However, such cyclic comonomers must constitute less than 20% by weight, preferably less than 10% by weight or less than 5% by weight, based on the total weight of the epoxide compounds.

[0072] [Curing agent] The present invention includes in the composition a curing agent that is comprised of one or more compounds that have at least one epoxide-reactive group and no disulfide functionality.

[0073] There is no intention to limit the curing agents that may be useful in the present invention. For example, the curing agent can include or consist of one or more compounds having at least two epoxide-reactive groups per molecule. Similarly, the curing agent can include or consist of a latent curing agent, including a photolatent curing agent. Within the context of the present invention, a combination of a reactive curing agent and a latent curing agent is contemplated. Regardless, the amount of curing agent present in the composition should generally be sufficient to cause complete curing of the epoxide compound.

[0074] More specifically, the amount of curing agent present in the composition should be such that the composition is characterized by a molar ratio of epoxide-reactive groups to epoxide groups of 0.6:1 to 1.2:1, e.g., 0.6:1 to 1.1:1, 0.7:1 to 1:1, or 0.75:1 to 1:1. A 1:1 molar ratio of epoxide-reactive groups to epoxide groups is particularly within these ranges. A highly preferred molar ratio of epoxide-reactive groups to epoxide groups, resulting in an excess of epoxide-reactive groups, is 0.75:1 to 0.95:1. Certainly, the term epoxide-reactive groups includes latent reactive groups, which are therefore included in the molar ratio term; as described later herein, a curing agent can contribute to the total epoxide-reactive groups present in the composition.

[0075] In complementary terms, the composition preferably comprises 0.01 to 25 wt. % of the curing agent of the epoxide compound, based on the weight of the composition. Preferably, the composition comprises 5 to 25 wt. %, for example 5 to 20 wt. % of the curing agent.

[0076] The reactive curing agent may include, among others, one or more of: i) at least one polyamine having at least two amine hydrogens reactive with epoxide groups; ii) at least one mercapto compound having at least two mercapto groups reactive with epoxide groups; and iii) at least one Mannich base.

[0077] The at least one polyamine having at least two amine hydrogens reactive with epoxide groups must in particular contain primary and / or secondary amine groups and have an equivalent weight per primary or secondary amine group of 150 g / eq or less, more preferably 125 g / eq or less.

[0078] Suitable polyamines that may be used alone or in combination include, but are not limited to: i) As aliphatic, cycloaliphatic or arylaliphatic primary diamines, the following may be mentioned by way of example: 2,2-dimethyl-1,3-propanediamine, 1,3-pentanediamine (DAMP), 1,5-pentanediamine, 1,5-diamino-2-methylpentane (MPMD), 2-butyl-2-ethyl-1,5-pentanediamine (Cneodiamine), 1,6-hexanediamine (hexamethylenediamine, HMDA), 2,5-dimethyl-1,6-hexanediamine, 2,2,4- and / or 2,4,4-trimethylhexamethylenediamine, 1,7-heptanediamine, 1,8-octanediamine, 1,9-nonanediamine, 1,10-decanediamine, 1,11-undecanediamine, 1,12-dodecanediamine, 1,2-, 1,3- and 1,4-diamines. norboranediamine, bis(4-aminocyclohexyl)methane, bis(4-amino-3-methylcyclohexyl)methane, bis(4-amino-3-ethylcyclohexyl)methane, bis(4-amino-3,5-dimethylcyclohexyl)methane, bis(4-amino-3-ethyl-5-methylcyclohexyl)methane, 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane (isophoronediamine, IPDA), 2- and / or 4-methyl-1,3-diaminocyclohexane, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, 2,5(2,6)-bis(aminomethyl)-bicyclo[2.2.1]heptane (norboranediamine, NBDA), 3(4),8(9)-bis(aminomethyl)tricyclo[5.2.1.0]heptane 2,6 ]-decane (TCD-diamine), 1,4-diamino-2,2,6-trimethylcyclohexane (TMCDA), 1,8-menthanediamine, 3,9-bis(3-aminopropyl)-2,4,8,10-tetraoxaspiro[5.5]undecane, and 1,3-bis(aminomethyl)benzene (MXDA).

[0079] ii) Specific examples of tertiary amine group-containing polyamines having two or three primary aliphatic amine groups include N,N'-bis(aminopropyl)-piperazine, N,N-bis(3-aminopropyl)methylamine, N,N-bis(3-aminopropyl)ethylamine, N,N-bis(3-aminopropyl)propylamine, N,N-bis(3-aminopropyl)cyclohexylamine, N,N-bis(3-aminopropyl)-2-ethylhexylamine, tris(2-aminoethyl)amine, tris(2-aminopropyl)amine, tris(3-aminopropyl)amine, and products from double cyanoethylation and subsequent reduction of fatty amines derived from natural fatty acids, such as N,N-bis(3-aminopropyl)dodecylamine and N,N-bis(3-aminopropyl)tallow alkylamine, commercially available as Triameen® Y12 D and Triameen® YT (Akzo Nobel).

[0080] iii) Specific examples of ether group-containing aliphatic primary polyamines include the following: bis(2-aminoethyl) ether, 3,6-dioxaoctane-1,8-diamine, 4,7-dioxadecane-1,10-diamine, 4,7-dioxadecane-2,9-diamine, 4,9-dioxadodecane-1,12-diamine, 5,8-dioxadodecane-3,10-diamine, 4,7,10-trioxatridecane-1,13-diamine, and higher oligomers of these diamines, bis(3-aminopropyl)polytetrahydrofuran, and Other polyoxyalkylene di- or -triamines are obtained as products from the amination of polyoxyalkylene di- and -triols, such as polytetrahydrofuran diamines, cycloaliphatic ether group-containing diamines obtained from the propoxylation and subsequent amination of 1,4-dimethylolcyclohexane, e.g., the material commercially available as Jeffamine® RFD-270 (Huntsman). Polyoxyalkylene di- and -triols are commercially available under the names Jeffamine® (Huntsman), Polyetheramines (BASF), or PC Amines® (Nitroil). Particular preference may be given to the use of Jeffamine® D-230, Jeffamine® D-400, Jeffamine® D-600, Jeffamine® D-2000, Jeffamine® D-4000, Jeffamine® T-403, Jeffamine® T-3000, Jeffamine® T-5000, Jeffamine® EDR-104, Jeffamine® EDR-148 and Jeffamine® EDR-176, as well as the corresponding amines from BASF or Nitroil.

[0081] iv) Examples of primary diamines having secondary amine groups include 3-(2-aminoethyl)aminopropylamine, bis(hexamethylene)triamine (BHMT); diethylenetriamine (DETA); triethylenetetramine (TETA); tetraethylenepentamine (TEPA); pentaethylenehexamine (PEHA); higher homologues of linear polyethyleneamines, such as polyethylenepolyamines having 5 to 7 ethyleneamine units (so-called "higher ethylenepolyamines", HEPA); multiple cyanoethylation or cyanoethylation of primary diamines and polyamines having at least two primary amine groups. and products from alkylation followed by hydrogenation, such as dipropylenetriamine (DPTA), N-(2-aminoethyl)-1,3-propanediamine (N3-amine), N,N'-bis(3-aminopropyl)ethylenediamine (N4-amine), N,N'-bis(3-aminopropyl)-1,4-diaminobutane, N5-(3-aminopropyl)-2-methyl-1,5-pentanediamine, N3-(3-aminopentyl)-1,3-pentanediamine, N5-(3-amino-1-ethylpropyl)-2-methyl-1,5-pentanediamine or N,N'-bis(3-amino-1-ethylpropyl)-2-methyl-1,5-pentanediamine.

[0082] v) Examples of polyamines having one primary amino group and at least one secondary amino group include: N-butyl-1,2-ethanediamine; N-hexyl-1,2-ethanediamine; N-(2-ethylhexyl)-1,2-ethanediamine; N-cyclohexyl-1,2-ethanediamine; 4-aminomethyl-piperidine; N-(2-aminoethyl)piperazine; N-methyl-1,3-propanediamine; N-butyl-1,3 -Propanediamine; N-(2-ethylhexyl)-1,3-propanediamine; N-cyclohexyl-1,3-propanediamine; 3-methylamino-1-pentylamine; 3-ethylamino-1-pentylamine; 3-cyclohexylamino-1-pentylamine; fatty diamines, such as N-cocoalkyl-1,3-propanediamine; primary aliphatic diamines with acrylonitrile, maleic or fumaric acid diesters, and citraconic acid diesters. products from Michael-type addition reactions in which methyl acrylates, acrylic and methacrylic acid esters, acrylic and methacrylic acid amides, and itaconic acid diesters are reacted in a 1:1 molar ratio; products from the partial reductive alkylation of primary polyamines with aldehydes or ketones, especially the N-monoalkylation products of the aforementioned polyamines having two primary amine groups, in particular 1,6-hexanediamine, 1,5-diamino-2-methylpentane, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, 1,3-bis(aminomethyl)benzene, BHMT, DETA, TETA, TEPA, DPTA, N3-amines, and N4-amines, where preferred alkyl groups are benzyl, isobutyl, hexyl, and 2-ethylhexyl; and partially styrenated polyamines, such as those commercially available as Gaskamine® 240 (Mitsubishi Gas Chemical Company, Inc.).

[0083] vi) Secondary diamines, in particular the N,N'-dialkylation products of the aforementioned polyamines having two primary amine groups, in particular 1,6-hexanediamine, 1,5-diamino-2-methylpentane, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, 1,3-bis(aminomethyl)benzene, BHMT, DETA, TETA, TEPA, DPTA, N3-amines or N4-amines, where preferred alkyl groups are 2-phenylethyl, benzyl, isobutyl, hexyl and 2-ethylhexyl.

[0084] vii) Aromatic polyamines may include m- and p-phenylenediamine; 4,4'-, 2,4'-, and 2,2'-diaminodiphenylmethane; 3,3'-dichloro-4,4'-diaminodiphenylmethane (MOCA); 2,4- and 2,6-tolylenediamine; a mixture of 3,5-dimethylthio-2,4- and -2,6-tolylenediamine (available from Albermarle as Ethacure® 300); a mixture of 3,5-diethyl-2,4- and -2,6-tolylenediamine (DETDA); 3,3',5,5'-tetraethyl-4,4'-diaminodiphenylmethane (M-DEA); 3,3',5,5'-tetraethyl-2 ,2'-Dichloro-4,4'-diaminodiphenylmethane (M-CDEA);3,3'-Diisopropyl-5,5'-dimethyl-4,4'-diaminodiphenylmethane (M-MIPA);3,3',5,5'-Tetraisopropyl-4,4'-diaminodiphenylmethane (M-DIPA);4,4'-Diaminodiphenylsulfone (DDS);4-Amino-N-(4-aminophenyl)benzenesulfonamide;5,5'-Methylenedianthranilic acid;Dimethyl-(5,5'-methylenedianthranilate);1,3-Propylene-bis(4-aminobenzoate);1,4-Butylene-bis(4-aminobenzoate);Polytetramethyleneoxide-bis(4-aminobenzoate)(Air Available as Versalink® from Chemical Products, Inc.; 1,2-bis(2-aminophenylthio)ethane, 2-methylpropyl-(4-chloro-3,5-diaminobenzoate); and tert-butyl-(4-chloro-3,5-diaminobenzoate).

[0085] viii) Representative polyamidoamines include the reaction products of mono- or polycarboxylic acids or their esters or anhydrides, especially dimeric fatty acids, with aliphatic, cycloaliphatic, or aromatic polyamines, such as polyalkyleneamines, such as DETA or TETA. Commercially available polyamidoamines include Versamid® 100, 125, 140, and 150 (manufactured by Cognis); Aradur® 223, 250, and 848 (manufactured by Huntsman); Euretek® 3607 and 530 (manufactured by Huntsman); and Beckopox® EH 651, EH 654, EH 655, EH 661, and EH 663 (manufactured by Cytec).

[0086] Illustrative compounds among the aforementioned polyamines having at least two primary aliphatic amine groups are: isophoronediamine (IPDA); hexamethylenediamine (HMDA); 1,3-bis(aminomethyl)cyclohexane; 1,4-bis(aminomethyl)cyclohexane; bis(4-aminocyclohexyl)methane; bis(4-amino-3-methylcyclohexyl)methane; NBDA; and ether group-containing polyamines having a number average molecular weight (Mn) of up to 500 g / mol, commercially available examples of which include Jeffamine® D-230 and D-600 (available from Huntsman).

[0087] As noted above, the compositions of the present invention may optionally contain as a curing agent at least one compound having at least two reactive mercapto groups per molecule, provided that the curing agent again does not have disulfide functionality. Suitable mercapto-containing compounds that can be used alone or in combination include, but are not limited to: Mercaptan-terminated polyoxyalkylene ethers obtained by reacting polyoxyalkylene di- and -triols with epichlorohydrin or alkylene oxides, followed by reaction with sodium hydrogen sulfide. Mercaptan-terminated compounds in the form of polyoxyalkylene derivatives known under the trade name Capcure® (manufactured by Cognis), in particular types WR-8, LOF and 3-800. Polyesters of thiocarboxylic acids, examples of which include pentaerythritol tetramercaptoacetate (PETMP); trimethylolpropane trimercaptoacetate (TMPMP); glycol dimercaptoacetate; and esterification products of polyoxyalkylene diols and triols, ethoxylated trimethylolpropane and polyester diols with thiocarboxylic acids, such as thioglycolic acid and 2- or 3-mercaptopropionic acid. 2,4,6-trimercapto-1,3,5-triazine, 2,2'-(ethylenedioxy)-diethanethiol (triethylene glycol dimercaptan) and / or ethanedithiol. · Tris(2-(mercaptopropionyloxy)ethyl)isocyanate.

[0088] It is found that the use of polyesters of thiocarboxylic acids, in particular at least one of pentaerythritol tetramercaptoacetate (PETMP), tris-(3-mercaptopropionate) (TMP), trimethylolpropane trimercaptoacetate (TMPMP), tris(2-(mercaptopropionyloxy)ethyl)isocyanate and glycol dimercaptoacetate, is preferred.

[0089] As mentioned above, the reactive curing agent can contain at least one Mannich base. Such compounds can be characterized by containing at least one phenalkamine, particularly a phenalkamine obtained from the condensation of cardanol (CAS No. 37330-39-5), an aldehyde, and an amine. The reactant amine in the condensation reaction is preferably ethylenediamine or diethyltriamine.

[0090] Mannich bases and phenalkamines are known in the art, and suitable examples include the commercially available phenalkamines Cardolite® NC-541, NC-557, NC-558, NC-566, Lite 2001 and Lite 2002 (available from Cardolite), Aradur® 3440, 3441, 3442 and 3460 (available from Huntsman), and Beckopox® EH 614, EH 621, EH 624, EH 628 and EH 629 (available from Cytec).

[0091] In the present invention, any common latent epoxy curing agent used in the art can be used without any particular limitation.For example, suitable latent epoxy curing agents that can be used in the present invention are described in U.S. Patent No. 4,546,155; U.S. Patent No. 7,226,976; U.S. Patent No. 4,833,226; JP 2008-214,567 A; UK Patent No. 1,121,196; WO 2014 / 165,423 A; and U.S. Patent No. 5,077,376 A. Further examples of commercially available latent epoxy curing agents include Ajicure PN-23, PN-40, PN-H, MY-24, and PN-50 available from Ajinomoto Co., Inc.; EH-4337 S, EH-3293 S, and EH-4357 S available from ADEKA Corporation; Novacure HX-3722 and HXA-3921 HP available from Asahi Kasei Corporation; and Sunmide LH-210, Ancamin 2014AS / FG, and Ancamin 2337S available from Air Products and Chemicals.

[0092] As known in the art, dicyandiamide is generally useful as a latent epoxy curing agent and can be used in the present composition. When used, the dicyandiamide is preferably in a finely divided form; an average particle size (d50) of 0.5 to 100 μm, e.g., 1 to 50 μm or 2 to 20 μm, is desirable. The particle size refers to the diameter or maximum dimension of the particle in the particle size distribution and can be measured by dynamic light scattering.

[0093] Further exemplary latent epoxy curing agents include, but are not limited to, ketimines obtained by the reaction of aliphatic polyamines with ketones; polyethyleneimines, particularly polyethyleneimines having a weight average molecular weight (Mw) of 700 to 1,000,000 g / mol; imidazole derivatives such as 2-heptadeoylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2-phenyl-4-benzyl-5-hydroxymethylimidazole, and the like; 2,4-diamino-8-2-methylimidazolyl-(1)-ethyl-5-triazine; addition products of triazines with isocyanuric acid; and hydrazides such as succinohydrazide, adipohydrazide, isofluranehydrazide, o-oxybenzohydrazide, salicylhydrazide, and the like.

[0094] [Repairing agent] The composition of the present invention is characterized in that it contains a restoring agent, which consists of at least one compound containing at least one disulfide functional group and, optionally, at least one epoxide-reactive group selected from hydroxyl, thiol, amine, or carboxyl.

[0095] In the absence of any epoxide-reactive groups, the healing agent will not react until reactive conditions are met such that a disulfide exchange reaction occurs. This embodiment presents the possibility that the healing agent may not be involved in the cure that achieves initial adhesion with a one-component (1K) composition, but may be activated within the cured matrix, allowing that matrix to re-adhere the substrates in a given assembly.

[0096] In a preferred alternative, where the restorative agent contains epoxide-reactive groups, it participates in a cure where initial adhesion is achieved. Broadly, the cure reaction yields a vitrimer where the polymer network topology obtained after the initial cure can be altered by thermally activating disulfide rearrangement.

[0097] Without being bound by theory, the initial cure involves two competing reactions: i) oligomer formation via epoxide ring opening by the epoxide-reactive groups of the curing agent and, if applicable, the repairing agent; and ii) crosslinking of oligomers via pendant reactive groups resulting from the epoxide ring opening. If the repairing agent contains epoxide-reactive groups, these can participate in the curing reaction, and under certain circumstances, the repairing agent can accelerate the cure rate. When the cure conditions are such that reversible cleavage and reformation of disulfide bonds occurs (usually at elevated temperatures), this increases the collision probability between epoxide groups and epoxide-reactive groups in the reaction mixture. However, a rapid reaction rate can affect the network topology in the cured resin, e.g., the stability of crystalline domains, by reducing the mobility of the oligomers that form and shortening the time for them to order before crosslinking occurs.

[0098] This consideration may be a determining factor in the molar amount of disulfide bonds introduced via a repair agent containing epoxide-reactive groups. The amount of repair agent must effectively promote matrix rearrangement upon thermal activation of the disulfide groups, but not be so excessive as to adversely affect the stability of the cured composition.

[0099] When formulating a curable composition, it is preferred that the composition comprises 0.01 to 10 wt. % of the restoring agent based on the weight of the composition. Preferably, the composition comprises 1 to 10 wt. %, for example 2 to 8 wt. % of the restoring agent.

[0100] In an important embodiment, the repair agent has the general formula (DS1): [ka] (In the formula: R p and R q are independently selected from the group consisting of: H; halogen; C-C 12 Alkyl; C6-C 18 Aryl, C1-C 12 Alkoxy; -(CO)R r , -O(CO)R r , -(SO)R r , -NH-CO-R r , -COOR r , -NR r R s ; R r and R s are independently selected from the group consisting of: -H, C-C 12 Alkyl and C6-C 18 aryl; and t is an integer between 0 and 4. The compound may comprise or consist of a compound having the formula:

[0101] With regard to general formula (DS1), the following are preferred: R p and R q are independently H, halogen, C1-C 12 Alkyl and C6-C 18 aryl; and t is an integer from 0 to 2. In particular examples, R p and R qis independently selected from the group consisting of H, halogen, and C1-C4 alkyl; and t is an integer from 0 to 2. Exemplary compounds according to formula (DS1) include, but are not limited to, bis(4-aminophenyl) disulfide; bis(2-aminophenyl) disulfide; and 2-amino-4-chlorophenyl disulfide.

[0102] In an alternative embodiment, the repair agent comprises or consists of a compound having the general formula (DS2): [ka] (In the formula, R g is H or C1-C6 alkyl; R h and R i are independently H, C1-C6 alkyl, COOR g , SH and OH; R j is NHR g , COOR g selected from the group consisting of , SH and OH; k is an integer from 0 to 10.

[0103] With respect to the general formula DS2, the following are preferred: R g is H;R h is H or C1-C6 alkyl; R i are independently H, C1-C6 alkyl, COOR g , SH, and OH; R j is NHR g , COOR g , SH, and OH; and k is an integer from 0 to 10. In particular examples, R g is H;R h is H;R i are independently H, C1-C6 alkyl, and COOR g selected from the group consisting of: R j is NHR g and COOR gand k is an integer from 0 to 10. Exemplary compounds according to formula (DS2) include, but are not limited to, 3,3'-dithiopropionic acid; 4,4'-dithiobutyric acid; bis-(10-carboxydecyl)disulfide; 2,2'-dithiobisethanamine (cystamine); and (2R)-2-amino-3-[[(2R)-2-amino-2-carboxyethyl]disulfanyl]propanoic acid (L-cystine).

[0104] Further compounds having utility as restorative agents include liquid mercaptan-terminated polysulfide polymers, commercially available examples of which include Thiokol® polymers (available from Morton Thiokol), particularly types LP-3, LP-33, LP-980, LP-23, LP-55, LP-56, LP-12, LP-31, LP-32, and LP-2; and Thioplast® G polymers (available from Akzo Nobel), particularly types G10, G112, G131, G1, G12, G21, G22, G44, and G4.

[0105] [Accelerator] The compositions of the present invention should preferably contain at least one accelerator. Accelerators are substances that promote the reaction of epoxide groups of the curing agent and, if applicable, the repair agent with epoxide-reactive groups, such as the reaction of amine or thiol groups with epoxide groups. A specific example concerns the use of amine accelerators, which deprotonate any reactive thiol (-SH) groups present to form thiolates (-S"). The thiolates react with the epoxide groups by nucleophilic ring-opening polymerization.

[0106] Although it is not intended to limit the accelerators used in the present invention, the following are suitable accelerators: i) acids or compounds hydrolyzable to acids, particularly a) organic carboxylic acids such as acetic acid, benzoic acid, salicylic acid, 2-nitrobenzoic acid, and lactic acid; b) organic sulfonic acids such as methanesulfonic acid, p-toluenesulfonic acid, and 4-dodecylbenzenesulfonic acid; c) sulfonic acid esters; d) inorganic acids such as phosphoric acid; e) Lewis acid compounds such as BF3 amine complexes, SbF6 sulfonium compounds, and bisarene iron complexes; f) Bronsted acid compounds such as pentafluoroantimonate complexes; and e) mixtures of the aforementioned acids and acid esters; ii) phenols, particularly bisphenols; ii) tertiary amines, e.g. imidazoles, such as 2-piperazin-1-ylethanolamine, 1,4-diazabicyclo[2.2.2]octane, benzyldimethylamine, α-methylbenzyldimethylamine, triethanolamine, dimethylaminopropylamine, N-methylimidazole, N-vinylimidazole, and 1,2-dimethylimidazole, and the salts of such tertiary amines; iii) quaternary ammonium salts, such as benzyltrimethylammonium chloride; iv) amidines, such as 1,8-diazabicyclo[5.4.0]undec-7-ene; v) guanidines, such as 1,1,3,3-tetramethylguanidine; vi) phenolic resins; and v) phosphites, such as di- and triphenyl phosphites.

[0107] In one embodiment, the accelerator for curing compositions based on epoxide compounds may be a photobase generator: upon exposure to UV radiation, typically at wavelengths of 320-420 nm, the photobase generator releases an amine, which catalyzes the addition of an epoxide-reactive group to the epoxide. The photobase generator is not particularly limited, as long as it generates an amine directly or indirectly upon irradiation with light. The preparation of suitable photobase generator compounds is known in the art, and a useful reference is U.S. Pat. No. 5,650,261 (Winkel). Apart from that, suitable photobase generators that may be mentioned include benzyl carbamate, benzoin carbamate, o-carbamoylhydroxyamine, o-carbamoyloxime, aromatic sulfonamides, alpha-lactams, N-(2-allylethenyl)amides, aryl azide compounds, N-arylformamides, and 4-(ortho-nitrophenyl)dihydropyridine.

[0108] In an alternative embodiment, the acid accelerator can be selected from photoacid generators (PAGs). Upon exposure to light energy, ionic photoacid generators undergo a fragmentation reaction, releasing one or more molecules of Lewis or Bronsted acids that catalyze the ring-opening and addition of pendant epoxide groups to form crosslinks. Useful photoacid generators are thermally stable, do not undergo heat-induced reactions with the forming copolymer, and are readily soluble or dispersible in the curable composition.

[0109] Exemplary cations that can be used as the cationic portion of the ionic PAGs of the invention include organic onium cations such as those described in U.S. Patent Nos. 4,250,311, 3,113,708, 4,069,055, 4,216,288, 5,084,586, 5,124,417, and 5,554,664. This reference specifically encompasses aliphatic or aromatic Group IVA and Group VIIA (CAS version)-centered onium salts, with I-, S-, P-, Se-, N-, and C-centered onium salts being preferred, such as those selected from sulfoxonium, iodonium, sulfonium, selenonium, pyridinium, carbonium, and phosphonium.

[0110] As is known in the art, the nature of the counteranion in an ionic photoacid generator (PAG) can affect the rate and extent of cationic addition polymerization of epoxide groups; for illustration, the reactivity ranking among commonly used nucleophilic anions is SbF > AsF > PF > BF. The influence of the anion on reactivity is due to three fundamental factors that one skilled in the art must address in this invention: (1) the acidity of the protonic or Lewis acid generated, (2) the degree of ion-pair separation in the propagating cationic chain, and (3) the susceptibility of the anion to fluoride abstraction and subsequent chain termination.

[0111] Overall, the photoinitiator should be present in the photocurable composition in an amount of 0 to 5 wt %, such as 0 to 2.0 wt % or 0 to 1.5 wt %, based on the total weight of the composition.

[0112] As will be recognized by those skilled in the art, photosensitizers can be incorporated into the composition to improve the efficiency with which the photoinitiator uses the supplied energy. The term "photosensitizer" is used according to its standard meaning to refer to a substance that increases the rate of photoinitiated polymerization or alters the wavelength at which polymerization occurs. When present, photosensitizers should be used in amounts of 5-25% by weight, based on the weight of the photoinitiator.

[0113] The use of photoinitiators (and photosensitizers, if applicable) can result in residual compounds from the photochemical reaction in the final cured product. The residues can be detected by conventional analytical techniques such as infrared, ultraviolet, NMR spectroscopy, gas or liquid chromatography, and mass spectrometry. Thus, the present invention can include a cured matrix (co)polymer and a detectable amount of residue from at least the photoinitiator. Such residues are small and typically do not interfere with the desirable physicochemical properties of the final cured product.

[0114] Although not intended to limit the invention, a mixture containing one or more photoinitiators can be irradiated with activating radiation to polymerize the monomer components contained therein. The purpose of irradiation is to generate active species from the photoinitiator that initiate the curing reaction. Once the species are generated, the curing chemistry is subject to the same thermodynamic rules as a thermal chemical reaction, and the reaction rate can be accelerated by heat.

[0115] Those skilled in the art will recognize that accelerator selection is not simply a matter of adding the fastest accelerator. Other factors that may determine accelerator selection include cost; toxicity; solubility; processing effects, such as working time, premature gelation, exothermic decomposition, expansion, off-gassing, etc.; and final properties, such as glass transition temperature (T g ), modulus, strength, elongation at break, chemical resistance, etc.; regulatory concerns; and ease of use.

[0116] In the present invention, it is preferred to use an accelerator comprising or consisting of at least one tertiary amine, at least one amidine, or a mixture thereof. More specifically, said accelerator should be selected from the group consisting of imidazole, methylimidazole, benzyldimethylamine, 1,8-diazabicyclo[5.4.0]undec-7-ene, 1,4-diazabicyclo(2.2.2)octane, and mixtures thereof.

[0117] The accelerator should desirably be present in the composition in an amount of 0.1 to 5% by weight based on the weight of the composition. The accelerator may constitute 0.1 to 2% by weight of the composition, for example 0.1 to 1% by weight.

[0118] [Electrolyte] The composition contains 0.5 to 15 wt. % of the electrolyte based on the weight of the composition. The electrolyte may preferably comprise 0.5 to 10 wt. % of the composition, e.g., 0.5 to 5 wt. %. These amounts are preferred because using an electrolyte in an amount greater than 15 wt. % based on the weight of the composition may provide good release, but may result in incomplete curing, thereby adversely affecting initial adhesion. Conversely, an amount less than 0.5 wt. % based on the weight of the composition may impair release.

[0119] The electrolyte comprises or consists of at least one salt according to formula (I) or formula (II): [ka] (In the formula, R 1 , R 2 , R 3 , R 4 and R 5 are independently hydrogen, C1-C 18 Alkyl, C3-C 18 Cycloalkyl, C6-C 18 Aryl, C7-C 24 Aralkyl, C2-C 20 Alkenyl, -C(O)R q , -C(O)OH, -CN or -NO 2 Selected from; R q is C1-C6 alkyl; X - is the counteranion.)

[0120] For completeness, in formula (I) and formula (II), C1-C n Alkyl, C3-C n Cycloalkyl, C6-C 18Aryl, C7-C 24 Aralkyl, C2-C 20 The term alkenyl means that one or more hydrogen atoms are substituted with a halogen atom (e.g., C1-C 18 haloalkyl) or hydroxyl groups (e.g., C1-C 18 Particularly preferred are groups substituted with R 1 , R 2 , R 3 , R 4 and R 5 are independently hydrogen, C1-C 18 Alkyl, C1-C 18 Haloalkyl, C1-C 18 Hydroxyalkyl or C3-C 18 For example, R 1 , R 2 , R 3 , R 4 and R 5 are independently hydrogen, C1-C 18 Alkyl or C1-C 18 It may be selected from haloalkyl.

[0121] There is no intention to limit the counter anions (X-) that can be used in the electrolyte. Exemplary anions can be selected from the following: · Halides; ·Formula PF6 - , CF3SO3 - , (CF3SO3)2N - , CF3CO2 - and CCl3CO2 - Pseudohalides and halogen-containing compounds of; ·CN - , SCN - and OCN - ; · Phenates; ·General formula SO4 2- , HSO4 - , SO3 2- , HSO3 - , R a OSO3 - and R a SO3 -sulfates, sulfites and sulfonates; ·General formula PO4 3- , HPO4 2- , H2PO4 - , R a PO4 2- , H.R. a PO4 - and R a R b PO4 - phosphates; ·General formula R a HPO3 - , R a R b PO2 - , and R a R b PO4 - phosphonates and phosphinates of; ·General formula PO3 3- , HPO3 2- , H2PO3 - , R a PO3 2- , R a HPO3 - and R a R b PO3 - Phosphites of; ·General formula R a R b PO2 - , R a HPO2 - , R a R b PO - and R a HPO - phosphonites and phosphinites; ·General formula R a COO - carboxylate anion; · Hydroxycarboxylic acid anions and sugar acid anions; · Saccharinates (salts of o-benzoic acid sulfimide); ·General formula BO3 3- , HBO3 2- , H2BO3 - , R a R b BO3 - , R aHBO3 - , R a BO3 2- , B(OR a )(OR b )(OR c )(OR d ) - , B(HSO 4 ) - and B(R a SO4) - Borates of; ·General formula R a BO2 2- and R a R b BO - Boronates of; ·General formula HCO3 - , Co3 2- and R a CO3 - carbonates and carbonate esters; ·General formula SiO4 4- , HSiO4 3- , H2SiO4 2- , H3SiO4 - , R a SiO4 3- , R a R b SiO4 2- , R a R b R c SiO4 - , H.R. a SiO4 2- , H2R a SiO4 - and H.R. a R b SiO4 - silicates and silicate esters; ·General formula R a SiO3 3- , R a R b SiO2 2- , R a R b R c SiO - , R a R b R c SiO3 - , R a Rb R c SiO2 - and R a R b SiO3 2- alkyl- and arylsilanolates; Pyridine and pyrimidinates; ·General formula: [ka] carboxylic acid imides, bis(sulfonyl)imides, and sulfonyl imides; ·General formula: [ka] methides; ·General formula R a O - alkoxides and aryloxides of; and ·General formula S 2- , H.S. - , [S v ] 2- , [HS v ] - and [R a S] - Sulfides, hydrogen sulfides, polysulfides, polyhydrogen sulfides and thiolates (In the general formula, v is a positive integer between 2 and 10, R a , R b , R c and R d are independently hydrogen, C1-C 12 Alkyl, C5-C 12 Cycloalkyl, C5-C 12 Heterocycloalkyl, C6-C 18 Aryl and C5-C 18 Heteroaryl.

[0122] In one embodiment, the counter anion (X - ) is preferably selected from the group consisting of: a OSO3 - sulfates of the general formula Ra SO3 - Sulfonic acid salts of the general formula R a PO4 2- , H.R. a PO4 - and R a R b PO4 - Phosphates of the general formula R a HPO3 - , R a R b PO2 - and R a R b PO3 - Phosphonates and phosphinates of the general formula PO3 3- , HPO3 2- , H2PO3 - , R a PO3 2- , R a HPO3 - and R a R b PO3 - Phosphite of the general formula R a R b PO2 - , R a HPO2 - , R a R b PO - and R a HPO - and phosphonites and phosphinites of the general formula: [ka] (In the formula, R a and R b is as defined above) Carboxylic acid imides, bis(sulfonyl)imides and sulfonyl imides.

[0123] The counter anion (X - ) with respect to R a and R b are independently hydrogen, C1-C 12 Alkyl or C1-C 12Preferably, R is selected from haloalkyl. For example, R a and R b may be independently selected from hydrogen, C-C alkyl, or C-C haloalkyl, or R a and R b may be independently selected from hydrogen, C1-C4 alkyl, or C1-C4 haloalkyl. Particularly preferred counter anions (X - ) are methyl sulfate, ethyl sulfate, methanesulfonate, bis(trifluoromethylsulfonyl)imide, and diethyl phosphate.

[0124] The electrolyte of the composition is preferably selected from the group consisting of: 1-ethyl-3-methyl-1H-imidazol-3-ium methanesulfonate; 1-ethyl-3-methyl-1H-imidazol-3-ium methylsulfate; 1-methylimidazolium bis(trifluoromethylsulfonyl)imide; 3-methylimidazolium bis(trifluoromethylsulfonyl)imide; 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide; 1-propyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide; 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide; 1-butyl-2,3-dimethylimidazolium bis(trifluoromethylsulfonyl)imide; 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide; 1-octyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide. 1-Methyl-3-octylimidazolium bis(trifluoromethylsulfonyl)imide; 1-decyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide; 1-dodecyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide; tetraethylphosphonium bis(trifluoromethylsulfonyl)imide; tetrabutylphosphonium bis(trifluoromethylsulfonyl)imide; tetraoctylphosphonium bis(trifluoromethylsulfonyl)imide; trihexyl(tetradecyl)phosphonium bis(trifluoromethylsulfonyl)imide; tridecyl(tetradecyl)phosphonium bis(trifluoromethylsulfonyl)imide; tributyl(methyl)phosphonium diethyl phosphate; tributyl(ethyl)phosphonium diethyl phosphate; tetraoctylphosphonium diethyl phosphate; and mixtures thereof. It may be mentioned that the use of at least one of 1-ethyl-3-methyl-1H-imidazol-3-ium methanesulfonate, 1-ethyl-3-methyl-1H-imidazol-3-ium methylsulfate, trihexyl(tetradecyl)phosphonium bis(trifluoromethylsulfonyl)imide, tributyl(methyl)phosphonium diethylphosphate and tributyl(ethyl)phosphonium diethylphosphate is particularly preferred.

[0125] The presence of compatible electrolyte compounds in the electrolyte that do not conform to formula (I) or formula (II) is not excluded, but said compounds of formula (I) or formula (II) should constitute at least 90% by weight of the electrolyte, preferably at least 95% by weight, more preferably at least 99% by weight, and most preferably 100% by weight.

[0126] [Rheology control agent] The compositions of the present invention conventionally include a rheology control agent that consists of a non-conductive filler, a conductive filler, or a mixture thereof.

[0127] The presence of a non-conductive filler in the composition can reduce the viscosity of the composition and the thermal expansion coefficient of the adhesive. Generally, there is no particular intention to limit the shape of the particles used as the non-conductive filler, and needle-shaped, spherical, ellipsoidal, cylindrical, bead-shaped, cubic, or plate-shaped particles can be used alone or in combination. Furthermore, the use of aggregates of multiple particle types is also contemplated. Similarly, there is no particular intention to limit the size of the particles used as the non-conductive filler. However, such non-conductive fillers have conventionally had an average volume particle size measured by laser diffraction / scattering of 0.01 to 1500 μm, e.g., 0.1 to 1000 μm, or 0.1 to 500 μm.

[0128] Exemplary non-conductive fillers include, but are not limited to, barium sulfate, calcium carbonate, calcium oxide, calcium metasilicate, silica, fumed silica, sand, quartz, zeolite, bentonite, magnesium carbonate, diatomaceous earth, alumina, clay, talc, flint, mica, glass powder, zinc oxide, and other ground mineral substances. Short fibers such as glass fiber, glass filament, polyacrylonitrile, carbon fiber, and polyethylene fiber can also be added. Preliminarily, it can be mentioned that non-conductive fillers selected from the group consisting of calcium carbonate, calcium oxide, calcium metasilicate, talc, fumed silica, silica, barium sulfate, and mixtures thereof are preferred. The use of precipitated silica and / or fumed (pyrogenic) silica as a rheology control agent in the present composition is particularly preferred. Such precipitated or pyrogenic silica preferably has a viscosity of 25 to 500 m, as measured by nitrogen adsorption according to DIN 66131. 2 / g, e.g., 100-250m 2 / g BET surface area. A commercial example of such a fumed (pyrogenic) silica is Aerosil 200 available from Evonik Industries.

[0129] Also suitable as non-conductive fillers are hollow spheres with mineral or plastic shells. These are, for example, hollow glass spheres commercially available under the trade name Glass Bubbles®. Plastic-based hollow spheres such as Expancel® or Dualite® can also be used and are described in EP 0 520 426. They are made of inorganic or organic materials and each have a diameter of 1 mm or less, preferably 500 μm or less, and more preferably 100 μm to 200 μm.

[0130] Non-conductive fillers that impart thixotropy to the composition may be useful in certain applications. Such fillers have also been described as rheological aids, such as hydrogenated castor oil, fatty acid amides, or swellable plastics such as PVC.

[0131] As mentioned above, the compositions of the present invention can further include a conductive filler as at least a portion of the rheology control agent. Generally, there is no particular intention to limit the shape of the particles used as the conductive filler, and acicular, spherical, ellipsoidal, cylindrical, bead-like, cubic, or plate-like particles can be used alone or in combination. Furthermore, the use of aggregates of multiple particle types is also contemplated. Similarly, there is no particular intention to limit the size of the particles used as the conductive filler. However, such conductive fillers conventionally have an average volume particle size, as measured by laser diffraction / scattering, of 1 to 500 μm, e.g., 1 to 200 μm.

[0132] Exemplary conductive fillers include, but are not limited to, silver, copper, gold, palladium, platinum, nickel, gold- or silver-coated nickel, carbon black, carbon fiber, carbon nanotubes, graphite, aluminum, indium tin oxide, silver-coated copper, silver-coated aluminum, metal-coated glass spheres, metal-coated fillers, metal-coated polymers, silver-coated fibers, silver-coated spheres, antimony-doped tin oxide, conductive nanospheres, nanosilver, nanoaluminum, nanocopper, nanonickel, carbon nanotubes, and mixtures thereof. Particulate silver and / or carbon black are preferably used as the conductive filler.

[0133] The total amount of rheology control agent present in the composition of the present invention is preferably 1 to 55 wt. %, more preferably 15 to 55 wt. %, based on the total weight of the composition. The desired viscosity of the curable composition formed by mixing the components is typically determined by the total amount of rheology control agent added. The composition should desirably have a viscosity of 3000 to 150,000 mPa·s, e.g., 5000 to 100,000 mPa·s. Within this viscosity range, the composition should be easily extrudable from a suitable dispensing device, such as a tube.

[0134] [Adjuvants and Additives] The compositions obtained by the present invention typically further comprise adjuvants and additives that can impart improved properties to these compositions. The adjuvants and additives can impart one or more of improved elastic properties, improved elastic recovery, extended workable time, reduced cure time, and reduced residual tack. These adjuvants and additives include solubilizers, tougheners, plasticizers, stabilizers including UV stabilizers, antioxidants, reactive diluents, driers, adhesion promoters, fungicides, flame retardants, color pigments or color pastes, and / or optionally slightly non-reactive diluents.

[0135] These adjuvants and additives may be used in any combination and proportion desired, provided that they do not adversely affect the properties and essential characteristics of the composition. Subject to possible exceptions, these adjuvants and additives should not exceed 50% by weight of the composition as a whole, and preferably should not exceed 20% by weight.

[0136] Based on the weight of the composition, the solubilizer can comprise 0-15 wt. %, e.g., 1-10 wt. % or 1-5 wt. %. The solubilizer functions to promote miscibility of electrolytes within the adhesive composition. The solubilizer may or may not form part of the polymer matrix formed upon curing of the adhesive composition, but serves to facilitate ion migration therein. The solubilizer is therefore preferably a polar compound, and is desirably liquid at room temperature.

[0137] Suitable classes of solubilizers include: polyphosphazenes; polymethylene sulfides; polyoxyalkylene glycols; polyethyleneimines; silicone surfactants such as polyoxyalkylene-modified polydimethylsiloxanes, including but not limited to polyalkylsiloxanes and poly(C2-C3)oxyalkylene-modified polydimethylsiloxanes; polyhydric alcohols; and sugars. For completeness, fluorinated silicone surfactants, such as fluorinated polysilanes, are intended to be encompassed by the term silicone surfactant.

[0138] Polyhydric alcohols and sugars, such as ethylene glycol, 1,3-propanediol, cyclohexanediol, hydroquinone, catechol, resorcinol, phloroglucinol, pyrogallol, hydroxyhydroquinone, tris(hydroxymethyl)benzene, tris(hydroxymethyl)benzene with three methyl or ethyl substituents attached to the remaining benzene carbon atoms, isosorbide, isomannide, isoidide, glycerol, cyclohexane-1,2,4-triol, 1,3,5-cyclohexanetriol, pentane-1,2,3-triol, hexamethylol, Examples of suitable hydroxybenzoates include 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, 1,1,1-tris(hydroxymethyl)ethane, di(trimethylolpropane), trimethylolpropane ethoxylate, 2-hydroxymethyl-1,3-propanediol, pentaerythritol allyl ether, and pentaerythritol.

[0139] Among the polyoxyalkylene glycols, it may be mentioned that it is particularly preferable to use polyoxy(C2-C3) alkylene glycols having a weight average molecular weight of 200 to 10,000 g / mol, for example 200 to 2,000 g / mol.

[0140] The optional presence of a toughening agent in an amount of up to 10 wt. % based on the weight of the composition may, in certain embodiments, be beneficial to debonding of the cured adhesive. Without intending to be bound by theory, the toughening agent may promote phase separation within the cured adhesive under an applied electric potential. Exemplary toughening agents can be selected from epoxy-elastomer adducts and toughened rubbers in the form of core-shell particles dispersed in an epoxy resin matrix.

[0141] The elastomer-containing adduct may be used alone or in combination with two or more specific adducts. Furthermore, each adduct can be independently selected from solid or liquid adducts at a temperature of 23°C. Typically, useful adducts are characterized by a weight ratio of epoxy to elastomer of 1:5 to 5:1, e.g., 1:3 to 3:1. A useful reference for suitable epoxy / elastomer adducts is U.S. Patent Application Publication No. 2004 / 0204551. Further, exemplary commercially available epoxy / elastomer adducts for use herein include, but are not limited to, HYPDX RK8-4, available from CVC Chemical; and B-Tough A3, available from Croda Europe Limited.

[0142] The term "core-shell rubber" or CSR is used according to its standard meaning in the art to refer to a rubber particle core formed from a polymer primarily composed of an elastomer or rubbery polymer and a shell layer formed from a polymer grafted onto the core. The shell layer partially or completely covers the surface of the rubber particle core in the graft polymerization process. By weight, the core must constitute at least 50% by weight of the core-shell rubber particle.

[0143] The polymeric material of the core must have a glass transition temperature (Tg) not exceeding 0° C., preferably not exceeding −20° C., more preferably not exceeding −40° C., and even more preferably not exceeding −60° C. The polymer of the shell is a non-elastomeric, thermoplastic or thermoset polymer with a glass transition temperature (Tg) above room temperature, preferably above 30° C., and more preferably above 50° C.

[0144] Without intending to limit the invention, the core can be composed of diene homopolymers, such as homopolymers of butadiene or isoprene; diene copolymers, such as 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)acrylic acid ester monomers, such as polybutyl acrylate; polysiloxane elastomers, such as polydimethylsiloxane and crosslinked polydimethylsiloxane.

[0145] Similarly, without intending to limit the invention, the shell may be composed of a polymer or copolymer of one or more monomers selected from (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)acrylamides. The polymer or copolymer used in the shell may have acid groups that are ionically crosslinked through metal carboxylate formation, particularly salt formation of divalent metal cations. The shell polymer or copolymer may also be covalently crosslinked by monomers having two or more double bonds per molecule.

[0146] Preferably, all core-shell rubber particles present have an average particle size (d50) of 10 nm to 300 nm, e.g., 50 nm to 250 nm. The particle size refers to the diameter or largest dimension of a particle in a particle distribution, as measured by dynamic light scattering. For completeness, the present application does not exclude the presence of two or more types of core-shell rubber (CSR) particles with different particle size distributions in the composition to provide a balance of important properties of the resulting cured product, such as shear strength, peel strength, and resin fracture toughness.

[0147] The core-shell rubber can be selected from commercially available products, examples of which include Paraloid EXL 2650A, EXL 2655, and EXL 2691A available from The Dow Chemical Company; Clearstrength® XT100 available from Arkema; ​​Kane Ace® MX series available from Kaneka Corporation, particularly MX 120, MX 125, MX 130, MX 136, MX 551, MX553; and METABLEN SX-006 available from Mitsubishi Chemical Corporation.

[0148] For purposes of the present invention, a "plasticizer" is a substance that reduces the viscosity of the composition and thus facilitates its processability, where the plasticizer can constitute up to 10% by weight or up to 5% by weight, based on the total weight of the composition, and is preferably selected from the group consisting of: diurethanes; monofunctional, linear or branched C4-C 16 Examples of suitable plasticizers include alcohol ethers, such as Cetiol OE (available from Cognis Deutschland GmbH, Düsseldorf); esters of abietic acid, butyric acid, thiobutyric acid, acetic acid, propionic acid, and citric acid; esters based on nitrocellulose and polyvinyl acetate; fatty acid esters; dicarboxylic acid esters; esters of OH-containing or epoxidized fatty acids; glycolic acid esters; benzoic acid esters; phosphate esters; sulfonic acid esters; trimellitic acid esters; polyether plasticizers, such as end-capped polyethylene or polypropylene glycol; polystyrene; hydrocarbon plasticizers; chlorinated paraffins; and mixtures thereof. In principle, phthalate esters could be used as plasticizers, but are not preferred due to toxicological possibilities.

[0149] For the purposes of the present invention, "stabilizer" is understood to mean an antioxidant, UV stabilizer, heat stabilizer, or hydrolysis stabilizer. Here, the stabilizers may constitute up to 10% by weight or up to 5% by weight in total, based on the total weight of the composition. Standard commercial examples of stabilizers suitable for use herein include sterically hindered phenols, thioethers, benzotriazoles, benzophenones, benzoates, cyanoacrylates, acrylates, amines of the hindered amine light stabilizer (HALS) type, phosphorus, sulfur, and mixtures thereof.

[0150] It should be noted that compounds having metal chelating properties may be used in the compositions of the present invention to enhance the adhesion of the cured adhesive to the substrate surface. Additionally, an acetoacetate-functionalized modified resin sold by King Industries under the trade name K-FLEX XM-B301 is also suitable for use as an adhesion promoter.

[0151] To further enhance shelf life, it is often desirable to use a desiccant to further stabilize the compositions of the present invention against moisture penetration. It is also sometimes necessary to use a reactive diluent to reduce the viscosity of the adhesive or sealant compositions of the present invention for specific applications. The total amount of reactive diluent present is typically 0 to 15 wt. %, for example 0 to 5 wt. %, based on the total weight of the composition.

[0152] The presence of solvents and non-reactive diluents in the compositions of the present invention is not excluded if they can effectively adjust the viscosity. For example, and by way of example only, the compositions may contain one or more of the following: xylene; 2-methoxyethanol; dimethoxyethanol; 2-ethoxyethanol; 2-propoxyethanol; 2-isopropoxyethanol; 2-butoxyethanol; 2-phenoxyethanol; 2-benzyloxyethanol; benzyl alcohol; ethylene glycol; ethylene glycol dimethyl ether; ethylene glycol diethyl ether; ethylene glycol dibutyl ether; ethylene glycol diphenyl ether; diethylene glycol; diethylene glycol monomethyl ether; diethylene glycol monoethyl ether; diethylene glycol mono-n-butyl ether; diethylene glycol dimethyl ether; diethylene glycol diethyl ether; diethylene glycol di-n-butyl ether; propylene glycol butyl ether; propylene glycol phenyl ether; dipropylene glycol; dipropylene glycol monomethyl ether; dipropylene glycol dimethyl ether; dipropylene glycol di-n-butyl ether; N-methylpyrrolidone; diphenylmethane; diisopropyl naphthalene; petroleum distillates, such as Solvesso® products (available from Exxon Corporation); alkylphenols, such as tert-butylphenol, nonylphenol, dodecylphenol, and 8,11,14-pentadecatrienylphenol; styrenated phenols; bisphenols; aromatic hydrocarbon resins, especially those containing phenolic groups, such as ethoxylated or propoxylated phenol; adipates; sebacates; phthalates; benzoates; organic phosphates or sulfonates; and sulfonamides.

[0153] Regardless of the above, it is preferred that said non-reactive diluents together constitute less than 10% by weight, in particular less than 5% by weight or less than 2% by weight, based on the total weight of the composition.

[0154] [Methods and Applications] The above components are mixed together to form an initial curable composition. As is known in the art, to form a one-component (1K) curable composition, the elements of the composition are mixed together to homogeneity under conditions that inhibit or prevent the reactive components from reacting. As will be readily understood by those skilled in the art, this may include mixing conditions that limit or prevent exposure to moisture, heat, or radiation, or that limit or prevent activation of the constituent latent catalysts. Therefore, it is often preferable not to mix the components by hand, but instead to mix them mechanically, e.g., by a static or dynamic mixer, in predetermined amounts under anhydrous conditions without intentional heating or radiation.

[0155] The first use of a one-component (1K) curable composition in forming a first adhesive structure will now be described. In accordance with the broadest process embodiment of the present invention, the composition is applied to a material layer and then cured in place. Prior to applying the composition, it is often desirable to pretreat the relevant surface to remove foreign matter therefrom. This step can promote adhesion of subsequent compositions, if applicable. Such treatments are known in the art and can be carried out in single- or multi-stage processes, for example, by using one or more of the following: etching with an acid appropriate for the substrate and, optionally, an oxidizing agent; ultrasonic treatment; plasma treatment, such as chemical plasma treatment, corona treatment, atmospheric plasma treatment, and flame plasma treatment; immersion in an aqueous alkaline degreasing bath; treatment with an aqueous cleaning emulsion; treatment with a cleaning solvent, such as carbon tetrachloride or trichloroethylene; and rinsing, preferably with deionized or demineralized water. If an aqueous alkaline degreasing bath is used, any remaining degreaser on the surface is preferably removed by rinsing the substrate surface with deionized or demineralized water.

[0156] In some embodiments, adhesion of the coating composition of the present invention to a preferably pretreated substrate can be promoted by applying a primer thereto. In fact, a primer composition may be necessary to ensure effective anchorage and / or cure time of the adhesive composition on an inert substrate. While those skilled in the art can select an appropriate primer, useful references for primer selection include, but are not limited to, U.S. Pat. No. 3,855,040; U.S. Pat. No. 4,731,146; U.S. Pat. No. 4,990,281; U.S. Pat. No. 5,811,473; British Patent No. 2,502,554; and U.S. Pat. No. 6,852,193.

[0157] The composition is then preferably applied to the surface of the pre-treated and optionally primed substrate by conventional application methods, such as brushing; roll coating; doctor blade application; printing methods; and spraying methods, including, but not limited to, air-atomized spraying, air-assisted spraying, airless spraying, and high-flow, low-pressure spraying.

[0158] As described above, the present invention provides an adhesive structure comprising a first substrate having an electrically conductive surface; and a second substrate having an electrically conductive surface, wherein a cured electrochemically releasable one-component (1K) adhesive composition as defined herein and in the appended claims is disposed between the first and second substrates. To produce such a structure, the adhesive composition is applied to at least one inner surface of the first substrate and / or the second substrate, and the two layers can then be brought into contact, optionally under pressure, so that the electrically releasable hot melt adhesive composition is sandwiched between the two substrates.

[0159] It is recommended that the composition be applied to the surface at a wet film thickness of 10 to 500 μm. Applying thinner layers within this range is more economical and reduces the possibility of harmful thick cured areas. However, strict control must be exercised when applying thinner coatings or layers to prevent the formation of discontinuous cured films.

[0160] Curing of the coating compositions of the present invention typically occurs at temperatures ranging from 40°C to 200°C, preferably from 50°C to 190°C, and especially from 60°C to 180°C. The appropriate temperature will depend on the particular compounds present and the desired cure rate, and can be determined in each case by those skilled in the art, using simple preliminary tests if necessary. Of course, curing at lower temperatures within the aforementioned ranges is advantageous, since this usually obviates the need for substantial heating or cooling of the mixture from prevailing ambient temperatures. However, if applicable, the temperature of the mixture formed from the components of a one-component (1K) composition may be elevated above the mixing and / or application temperatures using conventional means, including microwave induction.

[0161] For completeness, it should be noted that the present invention does not preclude the initial preparation of an epoxy adhesive in the form of a "film adhesive." A prepolymer mixture of epoxide compound, curing agent, healing agent, electrolyte, and any other desired components is applied as a coating to a plastic substrate, rolled up, and stored at a temperature low enough to inhibit chemical reaction between the components. When desired, the film adhesive is removed from the cold environment and applied to metal or composite components, the substrate is peeled off, the assembly is completed, and the adhesive is cured in an oven or autoclave.

[0162] The initial adhesion and subsequent de-adhesion and re-adhesion of the compositions of the present invention will now be described with reference to the accompanying drawings: FIG. 1a shows a bonded structure according to a first embodiment of the present invention. FIG. 1b shows a bonded structure according to a second embodiment of the invention. FIG. 2a shows the initial delamination of the structure of the first embodiment when current is applied to the structure. FIG. 2b shows the initial delamination of the structure of the second embodiment when current is applied to the structure. FIG. 3a shows a reconfiguration of the adhesive structure according to a first embodiment of the invention. FIG. 3b shows a reconfiguration of the adhesive structure according to a second embodiment of the invention. FIG. 3c shows a reconfiguration of the adhesive structure according to a third embodiment of the present invention.

[0163] As shown in accompanying Figure 1a, an adhesive structure is provided in which a layer of cured adhesive (10) is disposed between two conductive substrates (11). A layer of non-conductive material (12) can be disposed on the conductive substrate (11) to form a more complex adhesive structure, as depicted in Figure 1b. The conductive substrate (11) of each layer is in electrical contact with a power source (13), which may be a battery or a direct current (DC) alternating current power source. The positive and negative terminals of the power source (13) are shown in one fixed position, but those skilled in the art will recognize that the polarity of the system can be reversed.

[0164] The two conductive substrates (11) are shown in the form of layers, which may be composed of, among other things, metal films, metal sheets, metal meshes or grids, vapor-deposited metal particles, resin materials rendered conductive by conductive elements disposed therein, or conductive oxide layers. Exemplary conductive elements include silver filaments, single-walled carbon nanotubes, and multi-walled carbon nanotubes. Exemplary conductive oxides include doped indium oxide, such as indium tin oxide (ITO); doped zinc oxide; antimony tin oxide; cadmium stannate; and zinc stannate. Regardless of the conductive material selected, those skilled in the art will recognize that the effectiveness of the peeling operation may be reduced if the conductive substrate (11) is in the form of a grid or mesh, which limits contact with the cured adhesive layer (10).

[0165] When a voltage is applied between the conductive substrates (11), a current is supplied to the adhesive composition (10) disposed therebetween. This induces an electrochemical reaction at the interface between the substrate (11) and the adhesive composition. This electrochemical reaction is understood to be oxidative at the positively charged or anodic interface and reductive at the negatively charged or cathodic interface. This reaction is believed to weaken the adhesive bond between the substrates, allowing the release composition to be easily removed from the substrates.

[0166] As depicted in Figures 2a and 2b, delamination occurs at the positive interface, which is the interface between the adhesive composition (10) and the conductive surface in electrical contact with the positive electrode (11). Reversing the current direction before separating the substrates can weaken the adhesive bond at both substrate interfaces.

[0167] It should be noted, however, that the composition of the adhesive layer (10) can be tailored to allow delamination to occur at either the positive or negative interface, or both simultaneously. In some embodiments, applying a voltage to both surfaces to form an anodic and cathodic interface results in simultaneous delamination at both the anodic and cathodic adhesive / substrate interfaces. In an alternative embodiment, if the composition is insensitive to direct current at both interfaces, reverse polarity can be used to simultaneously delaminate both substrate / adhesive interfaces. The current can be applied in any suitable waveform, provided that the total time is sufficient to allow delamination to occur at each polarity. In this regard, sine waves, square waves, and triangular waves are suitable and can be applied from a controlled voltage or current source.

[0168] Without intending to limit the invention, it is believed that the peeling operation can be effectively performed when at least one, and preferably both, of the following conditions are met: a) an applied voltage of 0.5 to 100 V; and b) the voltage is applied for 1 second to 60 minutes. If removal of the conductive substrate from the cured adhesive is facilitated by the application of force, for example, via a weight or spring, the potential may only need to be applied for a few seconds. In some embodiments, a potential of 5 V for 10 minutes may be sufficient to achieve a peeling effect, while in some embodiments, a potential of 3.5 V for 30 minutes may be sufficient.

[0169] After peeling, it is desirable that the adhesive composition be located only on the first substrate or the second substrate, meaning that one of the substrates is substantially free of adhesive.

[0170] In the present disclosure, a method for forming a second bonded structure via re-adhesion includes the steps of providing a first re-adhesion substrate (RB1) resulting from the aforementioned electrochemical debonding process and having a residual cured adhesive composition disposed thereon; contacting the first re-adhesion substrate (RB1) with a second re-adhesion substrate (RB2) to interpose the residual cured adhesive composition therebetween; and heat-treating the residual cured adhesive composition. The term "third substrate" in the claims can be used synonymously with second re-adhesion substrate (RB2).

[0171] The second rebonding substrate (RB2) used is not intended to be particularly limited. The composition, physicochemical properties, and structure of the second rebonding substrate (RB2) can be selected independently of the substrate used in the initial bonded structure. However, it is envisioned that this substrate (RB2) can be provided by the remaining substrate from the peeling operation, so that the substrates (RB1, RB2) in the rebonding structure correspond to the first and second substrates of the initial bonded structure. Alternatively, a different substrate can be used as the substrate (RB2). In this regard, consideration should be given to the use of both conductive and non-conductive substrates. That is, if the former is selected, the application of a voltage to the rebonding structure creates anodic and cathodic interfaces, allowing for repeated electrochemical peeling operations. Conversely, selecting a non-conductive substrate as the substrate (RB2) would preclude such a repeatable process.

[0172] As mentioned above, the conductive substrate (RB2) can be composed of, among others, a metal film, a metal sheet, a metal mesh or grid, vapor-deposited metal particles, a resin material made conductive by conductive elements disposed therein, or a conductive oxide layer. Exemplary non-conductive substrates include thermoplastic polymer substrates, thermosetting polymer substrates, cellulosic substrates such as wood, leather, textile substrates, glass substrates, ceramic substrates, and composite materials.

[0173] Regardless of the choice of second re-adhesion substrate (RB2), the substrate may be pre-treated prior to the contacting step. Pre-treatment may be desirable to remove any relevant surface contaminants, and any of the techniques described above may be utilized to achieve this.

[0174] To ensure an effective fixation time, a primer composition comprising the repair agent defined above and, optionally, a solvent and / or non-reactive diluent can be interposed between the first (RB1) and second (RB2) rebonding substrates by the aforementioned contacting step. To achieve this, it is conceivable that a layer of the primer composition can be applied to the residual adhesive disposed on the first rebonding substrate (RB1). However, more conventionally, the optionally pretreated second rebonding substrate (RB2) can be treated with the primer composition before contacting it with the first rebonding substrate (RB1).

[0175] The primer composition may be applied to the relevant surface at a wet film thickness of 5 to 100 μm, for example 5 to 50 μm. In an alternative expression of this application, which is not intended to be mutually exclusive with that shown above, the primer composition may be applied at a wet film thickness of 0.01 to 10 g / m 2 , for example, 0.1 to 2 g / m 2 can be applied at a coating weight of

[0176] The heat treatment of the residual cured adhesive composition must obviously be sufficient to activate rearrangement of disulfides in the residual adhesive. Heat treatment typically involves exposing the residual cured adhesive composition to a temperature in the range of 60° C. to 200° C., preferably 60° C. to 175° C., and especially 60° C. to 120° C. The appropriate temperature will depend on the particular compounds present and can be determined in each individual case by one skilled in the art, using simple preliminary tests if necessary.

[0177] An exemplary embodiment of the reformation of a bonded structure using the adhesive composition of the present invention is shown in the accompanying Figures 3a to 3c, which show the presence of residual cured adhesive composition (30) on the conductive first re-adhesion substrate (31) obtained after the electrochemical peeling operation.

[0178] In the exemplary method of Figure 3a, a second, electrically conductive re-adhesion substrate (32), which itself has been peeled off, is brought back into contact with the residual adhesive layer (30). The second re-adhesion substrate is shown here free of adhesive residue, which may be the result of a peeling operation or a pre-treatment step that removes material from its surface. The contact between the first and second re-adhesion substrates (31, 32) places the previously cured adhesive between them. The resulting composite structure is subjected to the heat treatment conditions described above.

[0179] In the exemplary embodiment of Figure 3b, the second re-bonding substrate (34) is a new substrate in the sense that it is not part of the original composite structure that was debonded. The second re-bonding substrate (34) may have the same or different composition, physicochemical properties, and structure as the conductive first re-bonding substrate (31). Regardless, the second re-bonding substrate (34) is brought into contact with the conductive first re-bonding substrate (31), with the residual adhesive layer (30) interposed therebetween. The resulting composite structure is subjected to the heat treatment conditions described above.

[0180] For the sake of completeness, it is not excluded that the second re-adhesive substrate (34) of Figure 3b may be subjected to a pre-treatment step to remove foreign matter therefrom, as described above, before being adhered.

[0181] In the exemplary embodiment of FIG. 3c, the second substrate (36) is again a new substrate in the sense that it is not part of the original composite structure that was debonded. Again, the second rebond substrate (36) may have the same or different composition, physicochemical properties, and structure as the conductive first rebond substrate. However, in this embodiment, the optionally pretreated second substrate (36) is primed with a layer (37) of a composition comprising a healing agent and, optionally, a solvent or non-reactive diluent. The optionally pretreated and primed second rebond substrate (36) is contacted with the conductive first rebond substrate (31), with the residual adhesive layer (30) interposed therebetween, ensuring that the adhesive layer is in contact with the applied primer layer. The resulting composite structure is then subjected to the heat treatment conditions described above.

[0182] The following examples are illustrative of the present invention and are not intended to limit the scope of the present invention in any way. [Example]

[0183] The following materials were used in the examples: DER 331: Bisphenol-A epoxy resin, available from Olin. Thiocure 330: Trimethylolpropane tri(3-mercaptopropionate), available from Bruno Bock. Ajicure PN-H: Curing catalyst, available from Ajinomoto Fine-Techno Co., Ltd. Bis(2-aminophenyl) disulfide: hardener (rebonding), available from Apollo Scientific. 4-Aminophenyl disulfide: hardener (re-adhesion), available from Sigma Aldrich. Cyphos IL169: Tributyl(ethyl)phosphonium diethylphosphate, available from Solvay. EMIM MS: 1-ethyl-3-methylimidazolium methanesulfonate, available from Proionic. Premix 182: A premix of epoxy (DER331), fumed silica, and barbituric acid, available from Henkel. GPX801: Carbon black, available from Applied Nanostructured Solutions. Omyacarb 4-HD: Calcium carbonate filler, available from Omya. Luzenac 2: Layered talc filler, Imerys, available from Imerys. Aerosil 202: Fumed silica post-treated with polydimethylsiloxane, available from Evonik.

[0184] The following test methods were used to characterize the formulations:

[0185] Initial Adhesion Strength, Tensile Lap Shear (TLS) Test: The substrates tested were stainless steel (1.4301, 1.5 mm thick). The substrates were cut into 2.5 cm x 10 cm plates for tensile testing. The overlap area of ​​each plate was 2.5 cm x 1.0 cm (1 in x 0.4 in), resulting in a bond thickness of 150 microns. For the initial bonding operation, the applied adhesive composition was cured in the overlap area at 100°C for 30 minutes. Then, a tensile lap shear (TLS) test was performed at room temperature, based on EN 1465:2009 (German version) for determining the tensile lap shear strength of adhesive-bonded assemblies. The specimens were placed in the grips of a universal testing machine and pulled at 10 mm / min until failure occurred. The grips used to secure both ends of the assembly were aligned so that the applied force was along the centerline of the specimen. The type of failure observed could be either adhesive, where the adhesive separates from one substrate, or cohesive, where the adhesive ruptures within the adhesive itself.

[0186] Electrochemical peel, tensile lap shear (TLS) test (EN 1465:2009): Test specimens were prepared according to the method described above, but a constant potential (30 V) was applied to the overlap adhesive area for 20 minutes before being placed in the universal testing machine.

[0187] Re-adhesion methods: The specimens obtained after electrochemical peeling were treated in one of three ways. a) Method A: The stainless steel plates used as specimens in the TLS tests after electrochemical peel were used to regenerate adhesive assemblies, as depicted in Figure 3a. The adhesive overlap area was 2.5 cm x 1.0 cm (1 in x 0.4 in), with a bond thickness of 150 microns. The interposed adhesive was cured in the overlap area at 100°C or 140°C for 30 minutes. The temperatures used are recorded in the table below. b) Method B: The bonded assembly was reconstructed using one new stainless steel plate (1.4301, 2.5 cm x 10 cm x 1.5 mm), as depicted in Figure 3b. The bonded area was 2.5 cm x 1.0 cm (1 in x 0.4 in), with a bond thickness of 150 microns. The interposed adhesive was cured in the overlap area at 100°C or 140°C for 30 minutes. The temperatures used are recorded in the table below. c) Method C: As depicted in Figure 3c, one new stainless steel plate (1.4301, 2.5 cm x 10 cm x 1.5 mm) was used, and the surface of the plate was primed with the healing agent present in the adhesive composition, i.e., 4-aminophenyl disulfide or bis(2-aminophenyl) disulfide, to regenerate the adhesive assembly (Tables 1 and 3). The healing agent was applied to the overlapping area at a rate of 0.2 g / cm. 2 The adhesive overlap area was 2.5 cm x 1.0 cm (1 in x 0.4 in) and the adhesive thickness was 150 microns. The interposed adhesive was cured at 100°C or 140°C for 30 minutes. The application temperatures are recorded in the table below.

[0188] Following the TLS test procedure (EN 1465:2009) described above, the adhesive assemblies obtained using methods A to C were placed in the grips of a universal testing machine and pulled at 10 mm / min until failure occurred. The grips used to secure both ends of the assembly were aligned so that the applied force was applied along the centerline of the specimen. The type of failure observed could be either adhesive, where the adhesive separates from one substrate, or cohesive, where the adhesive ruptures within the adhesive itself.

[0189] Aging test: The tested substrates were aluminum (AA6016, 1.25 mm thick). The substrates were cut into 2.5 cm x 10 cm plates for tensile testing. The adhesive overlap area of ​​each substrate was 2.5 cm x 1.0 cm, with an adhesive thickness of 150 microns. The applied adhesive composition was cured at 100°C for 30 minutes in the overlap area. The specimens were stored in a climate chamber at 90% relative humidity and 65°C. At specified time points during storage (1 day, 7 days, 14 days, and 21 days), tensile lap shear (TLS) tests were performed at room temperature according to the method described above (EN 1465:2009, German version). The specimens were placed in the grips of a universal testing machine and pulled at 10 mm / min until failure occurred.

[0190] Example 1 A one-component composition having a molar ratio of epoxide reactive groups to epoxide groups of 0.8:1 was prepared according to Table 1 below. The given components were mixed in a speed mixer (1200 rpm; 1 minute) to ensure the formation of a homogeneous mixture.

[0191] [Table 1]

[0192] Tensile lap shear strength tests were performed as described above, and the results are shown in Table 2 below.

[0193] [Table 2]

[0194] It will be appreciated that this adhesive composition does not exhibit detrimental degradation of bond strength when the bonded assembly is exposed to high humidity and high temperature conditions. This indicates its potential usefulness in consumer products and devices, particularly electronic devices, that require operability over a wide range of operating temperatures and other environmental conditions. Furthermore, this adhesive composition exhibited effective electrochemical release when a 30 V potential was applied for 20 minutes, and furthermore, it showed at least 69% recovery of bond strength in all re-adhesion methods used.

[0195] Example 2 One-component compositions, each having a molar ratio of epoxide-reactive groups to epoxide groups of 0.8:1, were prepared according to Table 3 below. The given components were mixed in a speed mixer (1200 rpm; 1 minute) to ensure the formation of a homogeneous mixture.

[0196] [Table 3]

[0197] Tensile lap shear strength tests were performed as described above, and the results are shown in Table 4 below.

[0198] [Table 4]

[0199] Composition 2A exhibited effective electrochemical release at a 30 V potential for 20 minutes and demonstrated at least 53% bond strength recovery across all reattachment methods used. Composition 2B exhibited greater bond strength weakening under applied potential and demonstrated technically significant bond strength recovery across all reattachment methods.

[0200] Example 3 A 1K component composition was prepared according to composition 2A in Table 3 above. As before, the given components were mixed in a speed mixer (1200 rpm; 1 minute) to ensure a homogenous mixture.

[0201] Tensile lap shear strength tests were performed as described above in a repeatable manner, and the results are shown in Table 5 below.

[0202] [Table 5]

[0203] In view of the foregoing description and examples, it will be apparent to those skilled in the art that equivalent modifications can be made without departing from the scope of the appended claims.

Claims

1. a) at least one epoxide compound; b) a curing agent consisting of one or more compounds having at least one epoxide reactive group and no disulfide functionality; c) a repair agent consisting of one or more compounds containing at least one disulfide functional group and optionally at least one epoxide-reactive group selected from hydroxyl; thiol; amine; or carboxyl; and d) Electrolytes 1. A curable, electrochemically releasable one-component (1K) adhesive composition comprising: An adhesive composition wherein said composition is characterized by a molar ratio of epoxide-reactive groups to epoxide groups of 0.6:1 to 1.2:

1.

2. The composition comprises, based on the weight of the composition: 15 to 50 wt. % of a) at least one polyepoxide compound; 0.01 to 25 wt. % of b) a curing agent consisting of one or more compounds having at least two epoxide-reactive groups and no disulfide functionality; 0.01 to 10 wt. % of c) said restorative; 0.5 to 15 wt. % of d) said electrolyte; and 0-55 wt. % e) rheology control agent; Including, The adhesive composition of claim 1, wherein the composition is characterized by a molar ratio of epoxide-reactive groups to epoxide groups of 0.6:1 to 1.1:

1.

3. The composition comprises, based on the weight of the composition: 20 to 50 wt. %, preferably 20 to 40 wt. % of a) said at least one polyepoxide compound; 5 to 25% by weight, preferably 5 to 20% by weight, of said curing agent consisting of one or more compounds having at least two epoxide-reactive groups and no disulfide functionality; 1-10% by weight, preferably 2-8% by weight of c) said restorative; 0.5% to 10% by weight, preferably 0.5 to 5% by weight, of d) said electrolyte; and 1 to 55 wt. %, preferably 15 to 55 wt. % of e) said rheology control agent; Including, The adhesive composition of claim 2, wherein the composition is characterized by a molar ratio of epoxide-reactive groups to epoxide groups of 0.75:1 to 1.0.95:

1.

4. The composition of any one of claims 1 to 3, wherein the epoxide compound is selected from the group consisting of bisphenol A epoxy resins, bisphenol F epoxy resins, and mixtures thereof.

5. b) The composition of any of claims 1 to 4, wherein the curing agent comprises or consists of a thiol-functional compound selected from the group consisting of pentaerythritol tetramercaptoacetate (PETMP), tris-(3-mercaptopropionate) (TMP), trimethylolpropane trimercaptoacetate (TMPMP), tris(2-(mercaptopropionyloxy)ethyl)isocyanate, glycol dimercaptoacetate, and mixtures thereof.

6. 6. The composition of any of claims 1 to 5, wherein the repair agent comprises a compound selected from the group consisting of bis(4-aminophenyl)disulfide; bis(2-aminophenyl)disulfide; 2-amino-4-chlorophenyldisulfide; and mixtures thereof.

7. 6. The composition of any of claims 1 to 5, wherein the restorative agent comprises a compound selected from the group consisting of 3,3'-dithiopropionic acid; 4,4'-dithiobutyric acid; bis-(10-carboxydecyl)disulfide; 2,2'-dithiobisethanamine (cystamine); (2R)-2-amino-3-[[(2R)-2-amino-2-carboxyethyl]disulfanyl]propanoic acid (L-cystine); and mixtures thereof.

8. The composition of any of claims 1 to 5, wherein the restorative agent comprises a liquid mercaptan-terminated polysulfide polymer.

9. The electrolyte may comprise 1-ethyl-3-methyl-1H-imidazol-3-ium methanesulfonate; 1-ethyl-3-methyl-1H-imidazol-3-ium methylsulfonate; 1-methylimidazolium bis(trifluoromethylsulfonyl)imide; 3-methylimidazolium bis(trifluoromethylsulfonyl)imide; 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide; 1-propyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide; 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide; 1-butyl-2,3-dimethylimidazolium bis(trifluoromethylsulfonyl)imide; 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide; 1-octyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide; 1-methyl-3-octylimidazolium 9. The composition of any of claims 1 to 8, wherein the phosphonium bis(trifluoromethylsulfonyl)imide is selected from the group consisting of 1-decyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide; 1-decyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide; 1-dodecyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide; tetraethylphosphonium bis(trifluoromethylsulfonyl)imide; tetrabutylphosphonium bis(trifluoromethylsulfonyl)imide; tetraoctylphosphonium bis(trifluoromethylsulfonyl)imide; trihexyl(tetradecyl)phosphonium bis(trifluoromethylsulfonyl)imide; tridecyl(tetradecyl)phosphonium bis(trifluoromethylsulfonyl)imide; tributyl(methyl)phosphonium diethylphosphate; tributyl(ethyl)phosphonium diethylphosphate; tetraoctylphosphonium diethylphosphate; and mixtures thereof.

10. 10. The composition of claim 9, wherein the electrolyte is selected from the group consisting of 1-ethyl-3-methyl-1H-imidazol-3-ium methanesulfonate; 1-ethyl-3-methyl-1H-imidazol-3-ium methylsulfonate; trihexyl(tetradecyl)phosphonium bis(trifluoromethylsulfonyl)imide; tributyl(methyl)phosphonium diethylphosphate; tributyl(ethyl)phosphonium diethylphosphate; and mixtures thereof.

11. 11. The composition of any of claims 2 to 10, wherein the rheology control agent comprises a non-conductive filler selected from the group consisting of calcium carbonate; calcium oxide; calcium metasilicate; fumed silica; silica; talc; barium sulfate; and mixtures thereof.

12. a first substrate having an electrically conductive surface; and a second substrate having a conductive surface An adhesive structure comprising: An adhesive structure, wherein the cured adhesive composition according to any one of claims 1 to 11 is disposed between the first and second substrates.

13. i) applying a voltage to both surfaces to form an anodic interface and a cathodic interface; and ii) peeling the two surfaces The method for peeling off the adhesive structure of claim 12, comprising:

14. 14. The method according to claim 13, wherein the voltage applied in step i) is between 0.5 and 100 V, preferably for 1 second to 60 minutes.

15. i) applying a voltage to both surfaces to form an anodic interface and a cathodic interface; ii) peeling said surfaces apart to provide a first substrate having said cured adhesive composition disposed on its conductive surface; iii) contacting the first substrate with a third substrate such that the cured adhesive composition is interposed between the first and third substrates; and iv) heat treating the residual cured adhesive composition to bond the first and third substrates together.

13. A method for treating the bonded structure of claim 12, comprising:

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