Electrically de-bondable, chemically resistant adhesives

Abstract

Adhesive compositions comprising a polyurethane-based polymer that includes the reaction product of a polyisocyanate, a polyol, and a curable diol, wherein the polyol has a total solubility parameter of from 10 to 14 (cal / cm3)½; and a first ionic liquid. Articles including the disclosed adhesive compositions and methods of separating substrates adhered using the adhesive compositions.

Description

[0001] ELECTRICALLY DE-BONDABLE, CHEMICALLY RESISTANT ADHESIVES

[0002] FIELD

[0003] The present disclosure generally relates to the field of electrically debondable adhesives.

[0004] BACKGROUND

[0005] New adhesives are needed for use in the preparation of electronic devices and in various industrial applications. For example, in electronic devices, particularly mobile electronic devices (e.g., hand-held, or wearable electronic devices), various adhesives such as pressure-sensitive adhesives are used to bond the cover glass (or lens) to the underlying display module, bond the touch sensor to the cover glass and display, or bond the lower components of the display to the housing. The selected adhesive typically should have sufficiently high adhesive strength to properly maintain good adhesion to those components, not only when the mobile electronic devices are operating under normal conditions, but also when they are subjected to traumatic forces (e.g., when impacted and / or dropped onto a hard surface).

[0006] Further, new adhesives are needed for electronic devices that can perform well during the lifetime of the devices but that can be removed (e.g., de-bonded) from die electronic components after the useful lifetime of the device or to repair the device to extend its useful lifetime. Hie removal of the adhesives is preferably clean so that the electronic components can be reused or recycled, or so that the electronic device can be repaired. Additionally, debonding enables reworking of mistakes made during manufacturing before a device is fully assembled using the adhesives.

[0007] SUMMARY

[0008] The present disclosure provides polyurethane pressure-sensitive adhesive ("PSA") compositions that include electrically responsive ionic liquids and that also exhibit chemical resistance. Beneficially, the ionic liquid does not leach upon exposure to artificial sweat. Applying a voltage to the substrates bonded by the PSA drops adhesion by more than 50% and in some cases, up to 100%, even after exposure to artificial sweat.

[0009] In one aspect, provided herein are adhesive compositions comprising a polyurethane-based polymer that comprises the reaction product of a polyisocyanate, a polyol, and a curable diol, wherein the polyol has a total solubility parameter of from 10 to 14 (cal / cm3) / 2; and an ionic liquid. In another aspect, articles including the adhesive compositions are disclosed.

[0010] In another aspect methods of separating adhered substrates are provided.

[0011] As used herein:

[0012] The term “base polymer” refers to the polyurethane-based polymer.

[0013] The terms “a”, “an”, “the”, “at least one”, and “one or more” are used interchangeably.

[0014] The term “and / or” means one or both such as in the expression A and / or B refers to A alone, B

[0015] The term “alkyl” refers to a monovalent radical of an alkane. Suitable alkyl groups can have up to 50 carbon atoms, up to 40 carbon atoms, up to 30 carbon atoms, up to 20 carbon atoms, up to 16 carbon atoms, up to 12 carbon atoms, up to 10 carbon atoms, up to 8 carbon atoms, up to 6 carbon atoms, up to 4 carbon atoms, or up to 3 carbon atoms. The alkyl groups can be linear, branched, cyclic, or a combination thereof. Linear alkyl groups often have 1 to 30 carbon atoms, 1 to 20 carbon atoms, 1 to 10 carbon atoms, 1 to 6 carbon atoms, or 1 to 4 carbon atoms. Branched alkyl groups often have 3 to 50 carbon atoms, 3 to 40 carbon atoms, 4 to 20 carbon atoms, 3 to 10 carbon atoms, or 3 to 6 carbon atoms. Cyclic alkyl groups often have 3 to 50 carbon atoms, 5 to 40 carbon atoms, 6 to 20 carbon atoms, 5 to 10 carbon atoms, or 6 to 10 carbon atoms.

[0016] The term “alkylene” refers to a divalent group that is a radical of an alkane. The alkylene can be straight-chained, branched, cyclic, or combinations thereof. The alkylene typically has 1 to 20 carbon atoms. In some embodiments, the alkylene contains 4 to 14 carbon atoms, 1 to 10 carbon atoms, 1 to 8 carbon atoms, 1 to 6 carbon atoms, or 1 to 4 carbon atoms. The radical centers of the alkylene can be on the same carbon atom (i.e., an alkylidene) or on different carbon atoms. In certain embodiments, the alkylene can be substituted with an OH group.

[0017] The term “hydroxyl group” means a monovalent group of formula -OH.

[0018] The term “aryl” refers to a monovalent group that is radical of an arene, which is a carbocyclic, aromatic compound. The aryl can have one to five rings that are connected to or fused to the aromatic ring. The other ring structures can be aromatic, non-aromatic, or combinations thereof. Examples of aryl groups include, but are not limited to, phenyl, biphenyl, terphenyl, naphthyl, acenaphthyl, anthraquinonyl, phenanthryl, anthracenyl, pyrenyl, perylenyl, and fluorenyl.

[0019] The term “(meth)acrylate” means acrylate or methacrylate.

[0020] The term “(meth)acryloyl” refers to a group of formula CH2=CR-(C=O)- where R is hydrogen (for an acryloyl group) or methyl (for a methacryloyl group). The term “macromer” refers to a monomer having a polymeric group. A macromer is a subset of the term “monomer”.

[0021] The term “monomeric unit” refers to the reaction product of a polymerizable component (i.e., a monomer (including a macromer)) within the (meth)acrylate copolymer. As an example, the monomeric unit of acrylic acid where the asterisks (*) indicate the attachment site to another group such as another monomeric unit or terminal group in the (meth)acrylate copolymer.

[0022] The term “polyester” refers to repeating difunctional polymer wherein the repeat units are joined by ester linkages. Ester groups have the general formula -R — C(0) — OR’. The term “polyether” refers to repeating difunctional alkoxy radicals having the general formula -0-R-. Preferred R and R’ groups have the general formula -CnEhn- and include, for example, methylene, ethylene, propylene (including n-propylene and i-propylene) and butylene, or a combination thereof. Combinations of R and R’ groups may be provided, for example, as random or block type copolymers.

[0023] The term “pressure-sensitive adhesive” (“PSA”) is used in its conventional manner according to the Pressure-Sensitive Tape Council, which states that pressure-sensitive adhesives are known to possess properties including the following: (1) aggressive and permanent tack, (2) adherence with no more than finger pressure, (3) sufficient ability to hold onto an adherend, and (4) sufficient cohesive strength to be removed cleanly from the adherend. Materials that have been found to function well as PSAs include polymers designed and formulated to exhibit the requisite viscoelastic properties resulting in a desired balance of tack, peel adhesion, and shear holding power. PSAs are characterized by being normally tacky at room temperature (e.g., 20°C). Central to all PSAs is a desired balance of adhesion and cohesion that is often achieved by optimizing the physical properties of the elastomer, such as glass transition temperature and modulus. A pressure-sensitive adhesive may also meet the Dahlquist criterion described in Handbook of Pressure-Sensitive Adhesive Technology, D. Satas, 2nded., page 172 (1989).

[0024] The terms “ambient temperature” and “room temperature” refer to a temperature in the range of 20 degrees Celsius to 25 degrees Celsius, inclusive.

[0025] The terms “cure” and “curable” refer to joining polymer chains together by covalent chemical bonds, usually via crosslinking molecules or groups, to form a network polymer. Therefore, in this disclosure the terms “cured” and “crosslinked” may be used interchangeably. A cured or crosslinked polymer is generally characterized by insolubility but may be swellable in the presence of an appropriate solvent.

[0026] The term “polymerizable component” refers to any material (e.g., monomers, crosslinkers, oligomers, macromers, prepolymers, polymers, etc.) that participates in a curing or crosslinking reaction in forming a polymer and / or crosslinked polymer.

[0027] The term “resin” with respect to “parts per hundred parts resin” refers to 100 parts of the total polymerizable components.

[0028] The term “backbone” refers to the main continuous chain of a polymer.

[0029] The term “substantially”, unless otherwise specifically defined, means to a high degree of approximation (e.g., within + / - 10% for quantifiable properties) but again without requiring absolute precision or a perfect match. Terms such as same, equal, uniform, constant, strictly, and the like, are understood to be within the usual tolerances or measuring error applicable to the specific circumstance rather than requiring absolute precision or a perfect match.

[0030] By definition, the total weight percentages of all ingredients in a composition equals 100 weight percent.

[0031] The term “film” or “layer” refers to a single stratum within a multilayer film or article.

[0032] The term “substrate” encompasses films, layers, and articles.

[0033] The term “thickness” refers to the smallest dimension of a film or layer, e.g., in a z-axis while a major surface of the film or layer is in the x- and y-axes. Thickness may be determined using a micrometer gauge or doing a microscopic analysis of a cross-sectional sample of a layer or an article.

[0034] Features and advantages of the present disclosure will be further understood upon consideration of the detailed description as well as the appended claims.

[0035] BRIEF DESCRIPTION OF THE DRAWINGS

[0036] FIG. 1 is representation of the experimental setup for Electrical Debonding Tensile Pushout Testing.

[0037] Repeated use of reference characters in the specification and drawings is intended to represent the same or analogous features or elements of the disclosure. It should be understood that numerous other modifications and embodiments can be devised by those skilled in the art, which fall within the scope and spirit of the principles of the disclosure. The figures may not be drawn to scale. DETAILED DESCRIPTION

[0038] Electronics bonding customers desire the ability to de-bond pressure-sensitive adhesives ("PSAs") by applying an electrical current to the substrates in contact with the PSA. Applying a voltage to the substrates in contact with the adhesive should significantly lower the adhesion force and result in clean separation (i.e., no cohesive failure) from the substrates such that they can be recovered rapidly. In some applications, another desirable attribute is resistance to various household chemicals such as, for example, sweat, skin oils, sunscreen, and hand sanitizer, that the PSA may contact. The PSA should maintain its ability to electrically de-bond after exposure to these chemicals.

[0039] The present disclosure provides polyurethane PSA compositions that include electrically responsive ionic liquids and that also exhibit chemical resistance. Beneficially, the ionic liquid does not leach upon exposure to artificial sweat. Applying a voltage to the substrates bonded by the PSA drops adhesion by more than 50% and in some cases, up to 100%, even after exposure to artificial sweat.

[0040] Provided herein are adhesive compositions adhesive compositions comprising a polyurethane -based polymer that comprises the reaction product of a polyisocyanate, a polyol, and a curable diol, wherein the polyol has a total solubility parameter of from 10 to 14 (cal / cm3) / 2; and an ionic liquid.

[0041] Polyurethane-based polymers of the present disclosure may be prepared by methods known to those of ordinary skill in the relevant arts and are described in the Examples below. Polyisocyanates

[0042] Polyisocyanates useful in embodiments of the present disclosure may comprise various polyfiinctional isocyanate compounds. Examples of such polyfunctional isocyanate compound include polyfiinctional aliphatic isocyanate compounds, polyfunctional aliphatic cyclic isocyanate compounds, and polyfiinctional aromatic isocyanate compounds.

[0043] Examples of the polyfiinctional aliphatic isocyanate compounds include trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-propylene diisocyanate, 1,3-butylene diisocyanate, dodecamethylene diisocyanate, and 2,4,4-trimethylhexamethylene diisocyanate.

[0044] Examples of the polyfiinctional aliphatic cyclic isocyanate compounds include 1,3- cyclopentene diisocyanate, 1,3 -cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, isophorone diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated tetramethylxylene diisocyanate, and bio-based polyfunctional aliphatic cyclic isocyanates, such as 2-heptyl-3,4-bis(9- isocyanatononyl)-l -pentylcyclohexane from BASF Corporation under tradename DDI 1410.

[0045] Examples of the polyfunctional aromatic isocyanate compounds include phenylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 2,2'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-toluidine diisocyanate, 4,4'-diphenyl ether diisocyanate, 4,4'-diphenyl diisocyanate, 1,5 -naphthalene diisocyanate, and xylylene diisocyanate.

[0046] In some embodiments, the polyfunctional isocyanate comprises a polyisocyanate that is a liquid at 25 °C alone or in combination with minor amount of a polyisocyanate that is a solid at 25°C. In other embodiments, such as when the polyol is an aliphatic polyol, the polyfunctional isocyanate is a solid at 25 °C.

[0047] In some embodiments, the polyfunctional isocyanate compound comprises an aliphatic cyclic isocyanate compound, such as isophorone diisocyanate (“IPDI”), hexamethylene diisocyanate, or mixtures thereof. In other embodiments, the polyfunctional isocyanate compound comprises an ortho- or meta- aromatic isocyanate compound, such as 1,4 methylene diphenyl diisocyanate (“MDI”). Mixtures of (e.g. cyclic) aliphatic and aromatic polyfunctional isocyanate compounds may also be utilized.

[0048] In some preferred embodiments the polyisocyanate is selected from the group consisting of aliphatic polyisocyanates, aromatic polyisocyanates, and combinations thereof.

[0049] In some preferred embodiments the polyisocyanate comprises a linear diisocyanate.

[0050] In some preferred embodiments the polyisocyanate comprises a branched polyisocyanate having an isocyanate functionality of 2 to 4 inclusive.

[0051] Polyols

[0052] Polyols useful in embodiments of the present disclosure are selected to have certain solubility parameters computed employing group contribution methods as described in the paper by K.L. Hoy, J. Coated Fabrics, Volume 19, 53 (1989). The calculations were carried out employing the program Molecular Modeling Pro Plus from Norgwyn Montgomery Software, Inc. (North Wales, Pa.)

[0053] In preferred embodiments, the polyol has a total solubility parameter of at least 10 (cal / cm3)1 / 2. The total solubility parameter of the polyol is typically no greater than 14 (cal / cm3)1 / 2. In some embodiments, the total solubility parameter is no greater than 13, 12.5, 12, 11.5 or 11 (cal / cm3)1 / 2.

[0054] In some embodiments the polyol comprises a polyester polyol. In some embodiments the polyol is represented by the structure where

[0055] R is independently an alkylene group comprising 2 to 36 carbon atoms inclusive, optionally 2 to 9 carbon atoms inclusive,

[0056] R1is an alkylene group comprising 2 to 36 carbon atoms inclusive, optionally 4 to 9 carbon atoms inclusive, and n is 2 to 35 inclusive.

[0057] In some embodiments the polyol is represented by the structure where Ri is independently an alkylene group comprising 4 to 6 carbon atoms inclusive, n is 2 to 24 inclusive, and the ester group substituents are bonded to the ring in an ortho- and / or meta- orientation. In some embodiments, the polyol comprises a mixture of the polyols described above. Examples of such polyols include, for example, polyester polyol available under the trade name STEPANPOL PH-56, polyester polyol available under the trade name EMEROX 14550, polyester polyol available under the trade name XPS-221, and polyester polyol, available under the trade name DESMOPHEN 1700.

[0058] Curable Diols

[0059] Polyurethane adhesive compositions of the present disclosure comprise the reaction product of the above-described polyisocyanate and polyol components, as well as a curable diol, where the curable diol includes at least one of a (meth)acrylate functional group and an acid containing compound. Illustrative functional acid containing curable diol compounds include dihydroxycarboxylic acids, dihydroxysulphonic acids, dihydroxyphosphonic acids and salts thereof such as dimethylolpropionic acid (“DMPA”) depicted as follows (or its derivatives from GEO Specialty Chemicals, Inc. under tradenames such as DMPA Polyol HA-0135, DMPA Polyol HA-0135LV2, DMPA Polyol HC-0123 and DMPA Polyol BA-0132):

[0060] In some preferred embodiments the curable diol comprises a functional group selected from the group consisting of an acid functional group, a (meth)acrylate functional group, and combinations thereof.

[0061] Ionic Liquids

[0062] Adhesive compositions disclosed herein comprise at least a first ionic liquid and can undergo electrically induced adhesive debonding, wherein the adhesive composition can be debonded on demand with the application of a voltage across adherend substrates. Although not wanting to be limited by theory, it is believed that when a voltage is applied to the adhesive composition comprising an ionic liquid, electrolysis of the ionic liquid occurs, wherein the cations migrate toward the cathode side and the anions migrate toward the anode side, thereby weakening the adhesive interface. In some embodiments, adhesive compositions of the present disclosure further comprise a second ionic liquid.

[0063] In some embodiments, the first ionic liquid has hydroxyl functionality.

[0064] In some embodiments the first ionic liquid is independently selected from an ionic liquid which has monol or diol functionality.

[0065] In some embodiments the first ionic liquid has the structure wherein each R1comprises independently an alkyl, alicyclic, aryl, alkalicyclic, alkaryl, alicyclicalkyl, aralicyclic, or alicyclicaryl moiety, wherein such moiety may comprise one or more heteroatoms such as for example, nitrogen, oxygen, or sulfur, R1may be cyclic or aromatic and include N+ in the cycle;each R2comprises independently an alkyl, alicyclic, aryl, alkalicyclic, alkaryl, alicyclicalkyl, aralicyclic, or alicyclicaryl moiety, wherein such moiety may comprise one or more heteroatoms such as for example, nitrogen, oxygen, or sulfur, R2 may be cyclic or aromatic and include N+ in the cycle, and further has a primary or secondary alcohol group; a is an integer of 1 to 2; and X- is an anion with the proviso that if the cation is C8Hi7N+(CH3)(CH2CH2OH)2 the X- anion is not Br-, BF4-, or -O3SCH3.

[0066] In some embodiments the first ionic liquid comprises a (meth)acrylate moiety.

[0067] In some embodiments the first ionic liquid is a diol and the diol is incorporated into a polyurethane-based polymer backbone via the isocyanate / alcohol reaction. In some embodiments the first ionic liquid comprises a quaternary ammonium salt moiety.

[0068] In some embodiments the first ionic liquid comprises two quaternary ammonium salt moieties.

[0069] In some embodiments the first ionic liquid is selected from the group consisting of first ionic liquid is selected from the group consisting of l-butyl-3-methylimidazolium hexafluorophosphate, trimethyl ammonium ethyl acrylate bis(trifluoromethanesulfonyl)imide, trimethyl ammonium ethyl acrylate bis(fluorosulfonyl)imide, di-methyl-butyl-ammonium ethyl acrylate bis(fluorosulfonyl)imide, di-methyl-hexyl-ammonium ethyl acrylate bis(fluorosulfonyl)imide, l-butyl-3-methylimidazolium iodide, l-butyl-3-methylimidazolium tricyanomethanide, 3-sulfopropyl acrylate N-octyl-N-methyl-imidazolium, 3-sulfopropyl acrylate N-butyl-N-methyl-imidazolium, N-vinyl-imidazolium bis(fluorosulfonyl)imide, N-vinyl imidazolium hexafluorophosphate, sulfopropyl acrylamide N-butyl-N'-methyl imidazolium, sulfopropyl acrylamide N-octyl-N'-methyl imidazolium, styrene sulfonate N-butyl-N'-methyl imidazolium, styrene sulfonate N-octyl-N'-methyl imidazolium, l-butyl-3-methylimidazolium bis(fluorosulfonyl)imide, l-butyl-3-methylimidazolium thiocyanate, 1 -butyl- 1- methylpyrrolidinium dicyanamide, triethylsulfonium bis(trifluoromethylsulfonyl)imide, octylmethyl-bis(2-hydroxyethyl)ammonium bis(fluorosulfonyl)imide, octylmethyl-bis(2- hydroxyethyl)ammonium hexafluorophosphate, butylmethyl-bis(2-hydroxyethyl)ammonium bis(fluorosulfonyl)imide, dodecylmethyl-bis(2-hydroxyethyl)ammonium bis(fluorosulfonyl)imide, hexadecylmethyl-bis(2-hydroxyethyl)ammonium bis(fluorosulfonyl)imide, octylmethyl-bis(2-hydroxypropyl)ammonium bis(fluorosulfonyl)imide, octyldimethyl-(2-hydroxyethyl)ammonium bis(fluorosulfonyl)imide, octyldimethyl-(2- hydroxyethyl)ammonium hexafluorophosphate, 1 -methyl-3- [ 12-(3 -methylimidazol- 1 -ium- 1 - yl)dodecyl]imidazol-3-ium;di-hcxafluorophosphate, and combinations thereof.

[0070] In some preferred embodiments, the second ionic liquid is a diol where the diol is incorporated into a polyurethane-based polymer backbone via the isocyanate / alcohol reaction.

[0071] In some preferred embodiments the adhesive composition comprises

[0072] 5 to 20 wt.% of the polyisocyanate,

[0073] 60 to 90 wt.% of the polyol,

[0074] 0.2 to 10 wt.% of the curable diol; and

[0075] 0.5 to 25 parts per hundred, optionally 2 to 20 parts per hundred, optionally 5 to 15 parts per hundred of the ionic liquid based on the parts per hundred of the base polymer. In some embodiments the adhesive composition of the present disclosure further comprises an additive selected from the group consisting of a multifunctional epoxy resin, a photoinitiator, a pigment, a UV stabilizer, an antioxidant, and combinations thereof. In some embodiments the adhesive comprises a pressure -sensitive adhesive. In some embodiments the polyurethane -based polymer has a weight average molecular weight of 30,000 to 200,000 g / mol. In some embodiments the adhesive composition is a thermally curable composition, a UV- curable composition, or an e-beam curable composition.

[0076] Articles comprising the adhesives of the present disclosure are contemplated. The pressure sensitive adhesive article comprises an adhesive composition comprising the at least partially polymerized reaction product according to the present disclosure, wherein the adhesive composition is disposed on at least a portion of a substrate.

[0077] Liners

[0078] Suitable (e.g., release) liners may comprise flexible paper and polymeric fdms having sufficient dimensional stability to hold layers formed thereon in position without excessive stretching. Suitable paper liners include, but are not limited to, densified Kraft paper (commercially available from, for example, Loparex North America, Willowbrook, IL), polycoated paper such as polyethylene coated Kraft paper, and the like. Suitable polymeric film / liners include, but are not limited to, thermoplastic polymer films including polyalkylenes, e.g., polyethylene and polypropylene; polybutadiene, polyisoprene; polyalkylene oxides, e.g., polyethylene oxide; polyesters, e.g., PET and PBT; polyamides; polycarbonates, polystyrenes, block copolymers of any of the preceding polymers, and combinations thereof. Other suitable polymeric materials include polyimide, polysilicone, polytetrafluoroethylene, polyethylenephthalate, polyvinylchloride, or combinations thereof. Polymer blends of any of the above may also be employed, and nonwoven or woven liners may also be used.

[0079] In some embodiments, any or all of the major surfaces of a release liner may include a release coating, which may be the same or different, to tune or otherwise modify their release values. In various embodiments, which are not intended to be limiting, the release coatings applied to the major surfaces of the release liners may be selected from a fluorine-containing material, a silicone -containing material, a fluoropolymer, a silicone polymer, or a poly(meth)acrylate ester derived from a monomer including an alkyl (meth)acrylate having an alkyl group with 12 to 30 carbon atoms. In one embodiment, the alkyl group on the alkyl (meth)acrylate can be branched. Illustrative examples of useful fluoropolymers and silicone polymers can be found in U.S. Patent No. 4,472,480 (Olson), U.S. Patent No. 4,567,073 and U.S. Patent No. 4,614,667 (both Earson et al), incorporated herein by reference in their entireties. Illustrative examples of useful poly(meth)acrylate esters can be found in U.S. Patent Appl. Publ.

[0080] No. 2005 / 0118352 (Suwa), incorporated herein by reference in its entirety.

[0081] Carriers

[0082] In some embodiments, an adhesive composition may be easily coated upon a carrier film to produce adhesive coated sheet materials cured via ultraviolet radiation. Coating techniques known in the art may be used such as spray coating, flood coating, knife coating, Meyer bar coating, gravure coating, and double roll coating. The coating thickness will vary depending upon various factors such as, for example, the particular application or the coating formulation. Coating thicknesses of at least 10, 20, 25, 30, 40, 50, 60, 75, or even 100 pm (micrometers) and at most 125, 150, 200, 250, 300, or even 500 pm are contemplated. In some embodiments, having an adhesive layer with a thickness towards the higher end of the range may be preferable, for example, for better impact resistance performance.

[0083] The carrier film may be a flexible or inflexible backing material, a release liner, or a conductive carrier. Exemplary materials useful as the carrier film for the pressure sensitive adhesive articles of the disclosure include, but are not limited to, polyolefins such as polyethylene, polypropylene (including isotactic polypropylene and high impact polypropylene), polystyrene, polyester, including polyethylene terephthalate), polyvinyl chloride, poly(butylene terephthalate), poly(caprolactam), polyvinyl alcohol, polyurethane, poly(vinylidene fluoride), cellulose and cellulose derivatives, such as cellulose acetate and cellophane, and wovens and nonwovens. Commercially available carrier film include kraft paper (available from Monadnock Paper, Inc.); spun-bond poly(ethylene) and poly(propylene), such as those available under the trade designations “TYVEK” and “TYPAR” (available from The Chemours Co.); and porous films obtained from poly(ethylene) and poly(propylene), such as those available under the trade designations “TESLIN” (available from PPG Industries, Inc.), and “CELLGUARD” (available from Hoechst-Celanese). Exemplary conductive materials include for instance and without limitation, a layer of (e.g., metal) foil, a metal-coated polymeric film, a layer of a conductive primer coated onto or transferred onto the adhesive, a conductive primer deposited on a carrier layer, a conductive woven fabric, a conductive nonwoven fabric, a conductive mesh fabric (metal-coated insulative fibers), a conductive foam, a conductive elastomer, a conductive polymer film (e.g., poly(3,4-ethylenedioxythiophene), PEDOT) or coating on another film or polymer layer, and a conductive ceramic / alloy and / or oxides (e.g., Indium Tin Oxide, ITO) with or without a carrier layer.

[0084] The carrier film delivers the adhesive of the present disclosure to the desired substrate. The carrier film may comprise on the surface opposite the adhesive, a pigment, indicia, text, design, etc., which is then fixedly attached to the surface of the substrate or the carrier film may be free of such pigments and / or markings.

[0085] The thickness of an adhesive layer is typically at least 10, 15, 20, or even 25 microns and at most 50, 60, 70, 80, 90, 100, 400 microns, or 1000 microns thickness. The adhesive can be coated in single or multiple layers. In some preferred embodiments, the adhesive layer has a thickness of 10 to 1000 microns, optionally 50 to 300 microns, or optionally 75 to 200 microns. Backings

[0086] Adhesive compositions disclosed herein may advantageously be used to prepare a wide range of adhesive tapes and articles. Many of these tapes and articles contain backings or release liners used to support the layer of adhesive. As used herein a backing is a permanent support intended for final use of the adhesive article. A liner, on the other hand, is a temporary support that is not intended for final use of the adhesive article and is used during the manufacture or storage to support and / or protect the adhesive article. A liner is removed from the adhesive article prior to final use. To facilitate easy removal from the adhesive layer, the liner is typically coated with a release coating comprising a release agent. Such release agents are known in the art and are described, for example in "Handbook of Pressure Sensitive Adhesive Technology," D. Satas, editor, Van Nostrand Reinhold, New York, N.Y., 1989, pp. 585-600. In one embodiment, the release agent migrates to the surface (on the liner or release coating) to provide the appropriate release properties. Examples of release agents include carbamates, silicones and fluorocarbons. Illustrative examples of surface applied (i.e., topical) release agents include polyvinyl carbamates such as disclosed in U.S. Pat. No. 2,532,011 (Dahlquist et al.), reactive silicones, fluorochemical polymers, epoxysilicones such as are disclosed in U.S. Pat. Nos. 4,313,988 (Bany et al.) and 4,482,687 (Kessel et all), polyorganosiloxane-polyurea block copolymers such as are disclosed in EP Pat. No. 0250248 Bl (Leir et all), etc.

[0087] In some embodiments, the pressure sensitive adhesive article is a double-sided tape, featuring adhesive on opposite sides of a backing layer. The adhesives (i.e., a first adhesive layer and a second adhesive layer) on the two sides may be the same or different. The backing layer may be a film, a non-woven web, paper, or a foam as further described below. The double-sided tape may comprise one or two release liners protecting the adhesive surface not in contact with the backing layer. In one embodiment, the adhesive layer is disposed between two release liners, which may be the same or different. In another embodiment, the adhesive layer is disposed on a backing and the opposing side of the backing comprises a release agent. The adhesive article is wound upon itself such that the exposed surface of the adhesive layer (opposite the backing) contacts the release-coated backing forming, for example, a roll of tape. In yet another embodiment, the adhesive is disposed between a backing and release liner. In some embodiments, the adhesive tapes and articles do not contain a backing and therefore are freestanding adhesive layers. Transfer adhesive tapes are an example of such an adhesive article. Transfer adhesive tapes, also called transfer tapes, have an adhesive layer delivered on one or more release liners. The adhesive layer has no backing within it, so once delivered to the target substrate and the liner is removed, there is only adhesive. Some transfer tapes are multi-layer transfer tapes with at least two adhesive layers that may be the same or different. Transfer tapes are widely used in the printing and paper making industries for making flying splices, as well as being used for a variety of bonding, mounting, and matting applications both by industry and by consumers.

[0088] Advantageously, in some embodiments according to the present disclosure, an adhesive composition exhibits a tensile pushout strength of greater than 0.2 megaPascals (“MPa”), as determined by the Tensile Pushout Test Method. The Tensile Pushout Test Method is described in detail in the Examples below. In some cases, an adhesive composition exhibits a tensile pushout strength of greater than 0.3 MPa, 0.4 MPa, 0.5 MPa, 0.6 MPa, 0.7 MPa, 0.8 MPa, 0.9 MPa, 1.0 MPa, 1.1 MPa, 1.2 MPa, 1.3 MPa, 1.4 MPa, 1.5 MPa, 1.6 MPa, 1.7 MPa, 1.8 MPa, 1.9 MPa, 2 MPa. 12. 1 MPa, 2.2 MPa, 2.3 MPa, 2.4 MPa, 2.5 MPa, or even greater than 2.6. MPa, as determined by the Tensile Pushout Test Method.

[0089] In some embodiments according to the present disclosure, an adhesive composition exhibits a decrease in tensile pushout strength of at least 15% following subjection to 50 volts (V) for one minute or 5 minutes, as determined by the Tensile Pushout Test Method. In some cases, an adhesive composition exhibits a decrease in tensile pushout strength of at least (discuss limits) 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, or at least 95%, as determined by the Tensile Pushout Test Method. The decrease in tensile pushout strength following subjection to the voltage is a measure of the extent of electro-debonding capability of an adhesive composition, with a larger decrease indicating greater debonding.

[0090] In some embodiments, the peak stress required to debond adhered substrates is reduced by at least 50%, at least 60%, or at least 70% after applying the electric potential to the substrates. In some embodiments, applying the electric potential is for at least 5 minutes at 50V. In some preferred embodiments, the adhered substrates are exposed to artificial sweat before application of the potential. Objects and advantages of this disclosure are further illustrated by the following nonlimiting examples, but the particular materials and amounts thereof recited in these examples, as well as other conditions and details, should not be construed to unduly limit this disclosure.

[0091] EXAMPLES

[0092] Unless otherwise noted or readily apparent from the context, all parts, percentages, ratios, etc. in the Examples and the rest of the specification are by weight.

[0093] Table 1. Materials Used in the Examples.

[0094] Preparation of Materials Into a 3-necked 250mL flask equipped with overhead stirrer was charged C15 (100.00g,

[0095] 0.2359 equivalents, 424g / amine equivalent) and 3g of sodium carbonate. The flask was placed in a 110C bath, allowed to warm for 15 min with stirring under nitrogen, followed by addition of DMS (28.26g, 0.2241 equivalents) over about 20 min. The reaction ran at temperature for 16.5h at 110C and allowed to cool overnight to provide the desired product.

[0096] C25-DMS

[0097] In a fashion similar to that for C15-DMS, C25 (100.00g, 0.1158 equivalents, 863.5 g / amine equivalent), 3g sodium carbonate and DMS (13.88g, 0.1100 equivalents) were reacted to provide the desired product.

[0098] C15-FSI

[0099] A 3 -necked 250mL flask equipped with overhead stirrer was charged with C15-DMS (50.0g, 0.0909 equivalents, 550.13 equivalent weight) and about 63g water. Next LiFSI (18.70g, 0.100 equivalents) was dissolved in about 55g of water, and was added to the flask, which turned the solution milky. To the reaction was added CH2CI2 (200g). After 5 minutes of stirring the layers were separated and the lower organic layer was washed with 50g of water and the layers were again separated. The lower organic layer was dried over anhydrous magnesium sulfate, fdtered and concentrated at aspirator pressure on a rotary evaporator for 30 min at 60C to provide the product as a light brown oil.

[0100] C15-FSI-IEA

[0101] A two-necked 250mL flask equipped with a stirbar was charged with C15-FSI (15.00g, 0.0484 equivalents, 309.6g / hydroxyl equivalent weight), 10 mg of TEMPO, 5.5 mg of BHT, and 1 drop of XK-672 from a 2ml, 22cm Samco Scientific plastic pipette (available from Amazon.com). The flask was placed in a 55C bath under dry air, and IEA (6.84g, 0.0484 equivalents) were added to the flask over 30 min. The reaction was monitored by FTIR, and after 7h at 55C and cooling overnight, no -NCO peak at 2272 cm'1was present, providing the product as a thick brown oil.

[0102] C8-NMDEA-Br C8HI7N(CH3)(CH2CH2OH)2+ -Br A 500mL 3-necked flask equipped with overhead stirrer was charged with C8Br (81.03g, 0.4196 mol) and NMDEA (50.00g, 0.4196 mol) and placed under a nitrogen atmosphere in a bath that was heated from room temperature 80C over about 2h, then held at 90C overnight for about 24h. The material cooled to provide a clear glass.

[0103] C4-NMDEA-Br C4H9N(CH3)(CH2CH2OH)2+ -Br

[0104] In a manner similar to that for C8-NMDEA_Br, C4Br (57.49, 0.4196 mol) and NMDEA (50.00g, 0.4196 mol) were reacted to provide the desired product as a slightly yellow liquid.

[0105] C12-NMDEA-Br Ci2H25N(CH3)(CH2CH2OH)2+ -Br

[0106] In a manner similar to that for C8-NMDEA_Br, C12Br (43.54g, 0.175 mol) and NMDEA (23.13g, 0.194mol) were reacted at 115C for 17hto provide the desired product as a foamy solid.

[0107] C16-NMDEA-Br CI6H33N(CH3)(CH2CH2OH)2+ -Br

[0108] In a manner similar to that for C8-NMDEA_Br, C16Br (71.93g, 0.236 mol) and NMDEA (28.07g, 0.236 mol) were reacted at 125C for 16h, followed by addition of NMDEA (2.81g, 0.0236mol) at 145C for 16h to provide the desired product as a solid.

[0109] C8-NMDIPA-Br C8Hi7N(CH3)(CH2CH(OH)CH3)2+ -Br

[0110] A 500mL 3 -necked flask equipped with overhead stirrer under a nitrogen atmosphere was charged with C8Br (65.59g, 0.3396 mol) and NMDIPA (50.00g, 0.3396 mol) and placed under a nitrogen atmosphere in a bath that was heated from room temperature 115C over about 2h, then heated for an additional 30h at 125C to provide the material as a whitish solid filled with air bubbles.

[0111] C8-OMs C8HI7O3SCH3

[0112] To a 2L 3-neck RB with overhead stirrer was charged octanol (150.0g, 1.152 mol), TEA (139.86g, 1.38 mol), and EtOAc (450g). The flask was placed in an ice bath and cooled to an internal temperature of 5C. MsCl (151.73g, 1.325 mol) was added via a pressure equalizing over about Ih 20 min, keeping the temperature below 17C. The reaction was allowed to stir and warm to room temperature overnight. Concentrated HC1 (7.24g, mol) was added to make lOOOmL of solution to make 0.1M HC1. To the stirred reaction was added 900g of the 0.1 M HC1 solution and after 8 min, the reaction was poured into a 2L separatory funnel and the layers allowed to separate for 15 min. The top organic layer was then put back into the flask and stirred for 8 min with a solution made from mixing 225g of saturated brine with 225g of water and 150g of 5% aqueous sodium carbonate in water. The layers were separated and the isolated top organic layer was dried over MgSC>4, filtered and concentrated on a rotary evaporator at aspirator pressure for Ih at 60C. It was then further concentrated on a rotary evaporator at 107 Pa at 55C for 30 min.

[0113] C8-NMDEA-OMs C8Hi7N(CH3)(CH2CH2OH)2+ -O3SCH3

[0114] A 250mL 3-necked flask equipped with overhead stirrer under a nitrogen atmosphere was charged with C8-OMs (50.0g, 0.0.240 mol, 208.28 g / mol) and NMDEA (31.47g, 0.264mol) and placed in a bath that was heated from room temperature to 85C over about 30, then heated for an additional 20h at 85C to provide the material as a whitish solid.

[0115] C8-NMDEA-FSI C8Hi7N(CH3)(CH2CH2OH)2+ -N(SO2F)2 , octylmethyl-bis(2- hydroxyethyl)ammonium bis(fluorosulfonyl)imide

[0116] A 3 -necked 500mL flask equipped with overhead stirrer was charged with C8-NMDEA- Br (53.14g, 0.170 equivalents, 312.28 equivalent weight) and dissolved with heating in about 53g water. Next LiFSI (35.02g, 0. 187 equivalents) was dissolved in about 43g of water, and was added to the flask, which turned the solution milky. After stirring for 2 min, the reaction separated into a top cloudy layer and a lower clear layer. To the reaction was added CH2CI2 (200g). After 10 minutes of stirring, the layers were separated, and the lower organic layer was stirred with 100g water for 10 min and the layers were again separated. The lower organic layer was dried over MgSC>4, filtered and concentrated on a rotary evaporator at aspirator pressure for 30 min at 65C to provide the product as a viscous liquid.

[0117] C8-NMDEA-BF4 C8HI7N(CH3)(CH2CH2OH)2+ -BF4

[0118] A 3 -necked 500mL flask equipped with overhead stirrer was charged with C8- NMDEA-Br (55.23g, 0.177 equivalents, 312.28 equivalent weight) and dissolved with heating in about 55g water. Next NaBF4 (21.36g, 0.195 equivalents) was dissolved in about 35g of water, and was added to the flask, and the reaction stayed clear. The reaction was stirred with 250g of EtOAc for 4 min, then allowed to separate in a funnel. The top organic layer was stirred with 100g of water for 3 min, then allowed to separate in a funnel over a weekend. The top organic layer was dried over 25g of MgSC>4, filtered and concentrated on a rotary evaporator at aspirator pressure for at 65C for 45 min. It was then further concentrated on a rotary evaporator at 65-75C for 2h at 133 Pa to provide the material as a viscous oil.

[0119] C8-NMDEA-PF6 C8HI7N(CH3)(CH2CH2OH)2+ -PF6, octylmethyl-bis(2- hydroxyethyl)ammonium hexafluorophosphate A 3 -necked 500mL flask equipped with overhead stirrer was charged with C8-NMDEA- Br (51 ,77g, 0.166 equivalents, 312.28 equivalent weight) and dissolved with heating in about 52g water. Next NaPF6 (30.63g, 0.182 equivalents) was dissolved in about 31g of water, and was added to the flask, which turned the solution milky and quickly separated into two layers. To the reaction was added CH2CI2 (200g). After 5 minutes of stirring the layers were separated and the lower organic layer was washed with 150g of water, and the layers were again separated. The lower organic layer was dried over anhydrous magnesium sulfate, filtered and placed over activation 3 Angstrom sieves overnight. The layer was decanted from the sieves and concentrated at aspirator pressure on a rotary evaporator for 30 min at 65C to provide the product as a viscous oil.

[0120] C4-NMDEA-FSI C4H9N(CH3)(CH2CH2OH)2+ -N(SO2F)2 , butylmethyl-bis(2- hydroxyethyl)ammonium bis(fluorosulfonyl)imide A 3 -necked 500mL flask equipped with overhead stirrer was charged with C4-NMDEA-Br (52.19g, 0.2037 equivalents, 256.18 equivalent weight) and dissolved with heating in a 90C bath in about 52g water. Next LiFSI (40.02g, 0.2139 equivalents) was dissolved in about 40g of water, and was added to the flask, resulting in a single clear layer. After separating for 1.5h in a separatory funnel, the cooling mixture then provided two cloudy layers. The lower layer was stirred with 50g water at 55C providing a single layer which separated into two layers overnight. The lower organic layer was concentrated on a rotary evaporator at for 30 min at 60C at 72 Pa to provide the product as a viscous liquid.

[0121] C12-NMDEA-FSI Ci2H25N(CH3)(CH2CH2OH)2+ -N(SO2F)2 , dodecylmethyl-bis(2- hydroxyethyl)ammonium bis(fluorosulfonyl)imide

[0122] A 3-necked 250mL flask equipped with overhead stirrer was charged with C12- NMDEA-Br (66.2g, 0.179 equivalents, 368.39 equivalent weight) and dissolved with heating in a 90C bath in about 99g water. Next LiFSI (35.65g, 0.190 equivalents) was dissolved in about 40g of water, and was added to the flask, and stirred for a few minutes. The layers were separated in a 100C oven-heated separatory funnel. The lower organic layer was stirred at 90C with 70g water for 30 min and the layers were separated in a 100C oven-heated separatory funnel. The lower organic layer was concentrated on a rotary evaporator at for 30 min at 80C at 72 Pa to provide the product as a slightly yellow semi-solid.

[0123] C16-NMDEA-FSI CI6H33N(CH3)(CH2CH2OH)2+ -N(SO2F)2 , hexadecylmethyl-bis(2- hydroxyethyl)ammonium bis(fluorosulfonyl)imide A 3-necked IL flask equipped with overhead stirrer was charged with C16-NMDEA-Br (101.0g, 0.2379 equivalents, 424.5 equivalent weight) and dissolved with heating in a 90C bath in about 400g water. Next LiFSI (48.96g, 0.262 equivalents) was dissolved in about 60g of water, and was added to the flask, resulting in an immediate precipitate. I removed about 117g of the precipitate from the flask, putting it between two pieces of plastic wrap, rolled the material into a sheet, then removed the top plastic wrap. The precipitate was then dried at 90C in a vacuum oven at 23,700 Pa to provide 96g of product that was ground into a powder using liquid nitrogen a mortar and pestle and bottled.

[0124] C8-NMDIPA-FSI C8Hi7N(CH3)(CH2CH(OH)CH3)2+ -N(SO2F)2 , octylmethyl-bis(2- hydroxypropyl)ammonium bis(fluorosulfonyl)imide

[0125] A 3-necked 500mL flask equipped with overhead stirrer was charged with LiFSI (30.23g, 0.161 mol) and 30.2g water and placed in a 60C bath to dissolve the salt in the water. Next, C8- NMDEA-Br (50.00g, 0.147 equivalents, 340.34 equivalent weight) dissolved in 50.00g water was added to the flask and stirred for 20 min. The layers were separated, and the lower bottom layer was stirred with 50.0g water for 10 min, and the layers were again separated. The lower organic layer was concentrated on a rotary evaporator at aspirator pressure for 1 ,5h at 70C to provide the product as a viscous liquid.

[0126] C8-NNDMAE-FSI C8Hi7N(CH3)2CH2CH2OH+ -N(SO2F)2 , octyldimethyl-(2- hydroxyethyl)ammonium bis(fluorosulfonyl)imide

[0127] In a manner similar to that for C8-NMDIPA-FSI, LiFSI (35.56g, 0.195 mol) in 35.6 g water and C8-NNDMAE-OMs (50.00g solids, 0.147 equivalents, 298.1 equivalent weight) dissolved in 50.00g water were reacted and processed to provide the desired product.

[0128] C8-NNDMAE-PF6 C8HI7N(CH3)2CH2CH2OH+ -PF6, octyldimethyl-(2- hydroxyethyl)ammonium hexafluorophosphate

[0129] In a manner similar to that for C8-NMDIPA-FSI, KPF6 (33.11g, 0.180 mol) in 151 g water and C8-NNDMAE-OMs (52.96 g solids, 0. 178 equivalents, 298.1 equivalent weight) dissolved in about 60 g water were reacted and processed to provide the desired product.

[0130] C25-IEA-DMS

[0131] A IL 3necked roundbottom was charged with dried C25 (400.00g, 0.930 equivalents, 430g / equivalent, 207 ppm water), BHT (0.27g), TEMPO (0. 11g) under a dry nitrogen atmosphere. Next, IEA (131.28g, 0.930 equivalents) was added over 21 min, keeping the temperature below 65C. At 2h, with the temperature of the reaction at 50C, an aliquot was taken of the reaction, and the FTIR of that sample had no -NCO peak at 2275 cm’1.

[0132] To that same flask containing C25-IEA (531.28g, 0.4651 eq, 1142.26 equivalent weight), and the 0.38g of inhibitor, was charged via dropping funnel, DMS (55.73g, 0.4419 equivalents) over 25 min, maintaining the temperature below 55C. Next at 35 min, TEMPO (0.246g) was added to the reaction and the temperature was held at 50C for about 3.5h more, then allowed to cool with stirring to room temperature overnight, to provide the desired material.

[0133] Preparation of Cl-C12-Diimidazole diBr

[0134] MIMAZ (100g, 1.218 mol) was heated to 80 C and C12-2Br (99.5g, 0.303 mol) was added in portions as a solid, keeping the exothermic reaction below 100 C. The reaction was stirred 24h at 80C then cooled to RT and washed twice with acetone and separated in a separatory funnel. The top acetone layer was discarded. NMR indicated about 15 mol % 1- methylimidazole bottom layer remaining in the product so it was diluted with - 100 mb acetonitrile, then poured into 500 mb acetone and washed again and separated in a separatory funnel. The top acetone layer was discarded. This was repeated and then the residual solvent in the bottom phase was evaporated by rotary evaporation to give 124.03 (83.1%) of an orange viscous liquid (bis-imidazole salt, l-methyl-3-[12-(3-methylimidazol-l-ium-l- yl)dodecyl] imidazol-3 -ium;dibromide) .

[0135] Preparation of Cl-C12-Diimidazole diPF6

[0136] 2 PFS-

[0137] KPF6 (55 g, 298 mmol) was dissolved in about 800 mb water, and then poured into a separatory funnel. 100 mb CH2CL2 was then added. Bis imidazolium salt (65 g, 132 mmol) was dissolved in about 200 mb water, and that was poured into the separatory funnel. A phase separation occurred and the funnel was shaken and well mixed. Upon settling 3 layers were present. The bottom 2 layers were collected and the top layer extracted with 200 mL CH2CL2. The methylene chloride extract and bottom layers were combined and washed with 500 mL deionized water containing 2 g KPF6. The bottom layers were again collected and washed 2x 500 mL deionized water. The combined bottom 2 layers were collected and acetone was added until the layers combined into a homogenous solution. This was dried over MgSO4 and evaporated via a rotary evaporator to yield 77.93g of a yellow liquid, l-methyl-3-[12-(3- methylimidazol- 1 -ium- 1 -yl)dodecyl]imidazol-3-ium;di-hcxafluorophosphate.

[0138] PU-868

[0139] To a reaction vessel equipped with a mechanical stirrer, a condenser, and an air inlet, was added PH-56 (100.00g), Bis-GMA (1.15g), C15 FSI, (15.40g), Rubinate 9225 (10.25g), Tolonate X FLO 100 (26.32g) and 50 g MEK. The solution was heated up to 78°C and maintained at 78±2° while stirring until no NCO peak was observed by FT-IR. During the reaction, the desired amount of MEK was added to dilute the viscosity of the reactant. After the reaction, additional MEK was added to adjust the solid content of system to be 50 wt% and drained.

[0140] PU-909

[0141] To a reaction vessel equipped with a mechanical stirrer, a condenser, and an air inlet, was added PH-56 (100.00g), Bis-GMA (1.22g), C8-NMDEA-FSI (16.30g), Rubinate 9225 (12.22g), Tolonate X FLO 100 (31.38g) and 50 g MEK. The solution was heated up to 78°C and maintained at 78±2° while stirring until no NCO peak was observed by FT-IR. During the reaction, the desired amount of MEK was added to dilute the viscosity of the reactant. After the reaction, additional MEK was added to adjust the solid content of system to be 50 wt% and drained.

[0142] PU-910

[0143] To a reaction vessel equipped with a mechanical stirrer, a condenser, and an air inlet, was added PH-56 (100.00g), Bis-GMA (1.15g), C8-NMDEA-PF6 (12.03g), Rubinate 9225 (11.19g), Tolonate X FLO 100 (28.73g) and 50 g MEK. The solution was heated up to 78°C and maintained at 78±2° while stirring until no NCO peak was observed by FT-IR. During the reaction, the desired amount of MEK was added to dilute the viscosity of the reactant. After the reaction, additional MEK was added to adjust the solid content of system to be 50 wt% and drained.

[0144] Test Methods Peel Adhesion Testing (“Peel Adhesion Test Method”)

[0145] For all peel adhesion testing, the easy side, RF02N release liner (SKC Haas Display Films LLC, Seoul KR) was removed, and the exposed side of the tacky adhesive transfer tape was rolled by hand lamination using a 6 inch (15 cm) rubberized hand roller, (Polymag Tek, NY) onto a 6 inch (15 cm) wide primed polyester film backing (3M Company, St. Paul, MN), 2-mil (50 pm) biaxially oriented PET film with plasma treatment (conditions described in U.S. Pat. No. 10,134,566 (David et al.)) ensuring no air bubbles were trapped between the adhesive and the primed polyester film. Peel adhesion was measured at an angle of 180 degrees. Peel adhesion testing was performed on annealed 18-gauge, 304 stainless steel ("SS") from Chem. Instruments, Fairfield, OH). The RF12N release liner (SKC Haas Display Films LLC, Seoul KR) was removed from the tapes on PET backings and the adhesives were laminated directly to the 2- inch x 6-inch (5.08 cm x 15.24 cm) substrate using a weighted rubberized (4.5 lb, 2.04 kg) hand roller with four repetitions of 3 -second roll downs. This method followed ASTM D3330, test method E, liner side. All samples and substrates were conditioned in a controlled temperature and humidity ("CTH") room (set at 23°C, 50% RH (relative humidity)) prior to peel testing. SS test panels were cleaned with methyl ethyl ketone before and after testing. Peel testing was done using an SP-2300 iMass (iMass Inc., Accord, MA USA) at a rate of 12 inches / min (0.3 m / min) after a dwell time of 20 minutes or 20 hours as indicated.

[0146] Rheology and Glass Transition Temperature

[0147] Rheological testing was performed on an TA Instruments discovery hybrid rheometer (DHR-3), (New Castle, DE). All data was collected by heating / cooling at a rate of 3 °C / min at oscillatory frequencies of 1 Hz with strain values in the linear viscoelastic regime (1 to 5%). The glass transition temperature (at 1 Hz) was determined as the peak of the tan(5) curve from the rheology plot of G’ and G” (y axis -1) vs. temperature (°C), (x axis) and tan(5) (y axis-2). The peak (i.e. highest value) in tan(5) was selected from y axis-2, and the corresponding temperature on the x axis was selected as the glass transition temperature. Tan(5) is an abbreviation for the tangent of the phase angle between the stress and strain oscillation waves in the shear rheology oscillation.

[0148] Electrical Debonding Tensile Pushout Testing (“Tensile Pushout Test Method”)

[0149] The experimental setup is represented in FIG. 1. A stainless-steel coupon (40mm x 40mm x 3mm) containing a hole in the center (diameter= 24 mm) and a circular stainless-steel puck (diameter = 33mm, 3 mm thick) were adhered using a ring shaped adhesive (outer diameter = 31 mm, inner diameter = 26 mm, 8 mil thick). Samples were weighed down with 8 kg for 30 seconds at 23 °C and dwelled for 1 day at controlled temperature and humidity conditions (23 °C / 50% RH). Then, a BK Precision 1685 B power source was connected to the coupon and puck via a positive and negative electrode. For 300 seconds, a voltage of 50 V was applied across the coupon and puck. Immediately after this time, the samples were disconnected from the power source electrodes and loaded onto an MTS Criterion. The puck was pushed out from the coupon in the direction shown in FIG. 1 at a rate of 10 mm / min. The peak stress required to remove the puck from the coupon was recorded in MPa. Samples where no voltage was applied were also tested in this way and the peak stress for these measurements are reported in Table 5 as "Initial peak stress (MPa)".

[0150] Electrical Debonding ("Push-out") Testing with Artificial Sweat

[0151] The experimental setup is represented in FIG. 1. A stainless steel coupon (40mm x 40mm x 3mm) containing a hole in the center (diameter= 24 mm) and a circular stainless steel puck (diameter = 33mm, 3 mm thick) were adhered using a ring shaped adhesive (outer diameter = 31 mm, inner diameter = 26 mm, 8 mil thick). Samples were weighed down with 8 kg for 30 seconds at 23 °C and dwelled for 1 day at controlled temperature and humidity conditions (23 °C / 50% RH). The samples were then submerged in artificial sweat (1700-0531, obtained from Pickering Laboratories) at 40 °C for 1 day and then wiped clean with a Kimwipe and conditioned for 1 hour at controlled temperature and humidity (23 °C / 50% RH). Then, a BK Precision 1685 B power source was connected to the coupon and puck via a positive and negative electrode. For 300 seconds, a voltage of 50 V was applied across the coupon and puck. Immediately after this time, the samples were disconnected from the power source electrodes and loaded onto an MTS Criterion. The puck was pushed out from the coupon in the direction shown in FIG. 1 at a rate of 10 mm / min. The peak stress required to remove the puck from the coupon was recorded in MPa. Samples where no voltage was applied were also tested in this way and the peak stress for these measurements are reported in Table 5 as ‘Initial peak stress (MPa)’.

[0152] Sample Preparation

[0153] Polyurethane ("PU") Synthesis

[0154] The compositions used to synthesize the PU polymers are summarized in Table 2. To a resin reaction vessel equipped with a mechanical stirrer, a condenser and a nitrogen inlet were added polyols, isocyanates, catalyst XK-651 (500 ppm based on total solid) and MEK of 50.0 grams. The reactants were stirred and heated up to 78 °C for reaction. The temperature was maintained at 78 ± 2 °C until no free NCO group was observed by FT- IR at around 2270 cm'1. During the reaction, MEK was added to adjust the viscosity. After reaction, the PU solution with a solid content of 50 wt% was obtained with an IV range from 0.43-0.56. Also see the descriptions for the synthesis ofPU-868, PU-909, and PU-910.

[0155] Preparation of Transfer Tape Samples

[0156] Adhesive sample formulations are summarized in Table 3 and Table 6. Approximately 20-40 g of a given PU solution was measured into a glass jar. The appropriate amounts of additives were then thoroughly mixed with the PU solution. Ionic liquid was added directly, except in the case of TMAEA TFSI, which was added as a 50 wt% solution in MEK. Tetrad-X was added as a 20 wt% solution in MEK. For samples with photoinitiators (Irgacure 651 or TPO-L), the photoinitiator was added as a 5 wt% solution in MEK. Once the adhesive formulation was thoroughly mixed, it was coated onto RF12N release liner (SKC Haas Display Films LLC, Seoul KR) with a coater gap of 14 mil (28 mil for El -2, CE1-2). MEK solvent was removed by heating the sample in an exhausted oven at 60 °C for 10 min, then 80 °C for 10 min, then 100 °C for 10 min. Then, RF02N release liner (SKC Haas Display Films LLC, Seoul KR) was laminated onto the exposed adhesive surface. The samples were cured either by thermal treatment (120 °C for 60 min) or UV (1-6 J / cm2UVA).

[0157] Table 2. Base Polymer Composition and IV Measurements

[0158] Table 3. Adhesive Sample Compositions

[0159] Table 4. Rheological and Adhesion Properties of Coated Adhesive Samples Table 5. Electrical De-bonding Results of Tensile Push-out Test

[0160] Table 6. Adhesive Sample Compositions Table 7. Electrical De-bonding Results of Tensile Push-out Test All cited references, patents, and patent applications in the above application for letters patent are herein incorporated by reference in their entirety in a consistent manner. In the event of inconsistencies or contradictions between portions of the incorporated references and this application, the information in the preceding description shall control. The preceding description, given in order to enable one of ordinary skill in the art to practice the claimed disclosure, is not to be construed as limiting the scope of the disclosure, which is defined by the claims and all equivalents thereto.

Claims

What is claimed is:

1. An adhesive composition comprising: a polyurethane-based polymer that comprises the reaction product of a polyisocyanate, a polyol, and a curable diol, wherein the polyol has a total solubility parameter of from 10 to 14 (cal / cm3) / 2; and a first ionic liquid.

2. The adhesive composition of claim 1 , wherein the polyisocyanate is selected from the group consisting of aliphatic polyisocyanates, aromatic polyisocyanates, and combinations thereof.

3. The adhesive composition of claim 1 or claim 2, wherein the polyisocyanate comprises a linear diisocyanate.

4. The adhesive composition of claim 1 or claim 2, wherein the polyisocyanate comprises a branched polyisocyanate having an isocyanate functionality of 2 to 4 inclusive.

5. The adhesive composition of any one of claims 1 to 4, wherein the polyol comprises a polyester polyol.

6. The adhesive composition of any one of claims 1 to 4, wherein the polyol is represented by the structurewhereinR is independently an alkylene group comprising 2 to 36 carbon atoms inclusive, optionally 2 to 9 carbon atoms inclusive,R1is an alkylene group comprising 2 to 36 carbon atoms inclusive, optionally 4 to 9 carbon atoms inclusive, and n is 2 to 35 inclusive.

7. The adhesive composition of any one of claims 1 to 4, wherein the polyol is represented by the structurewherein Ri is independently an alkylene group comprising 4 to 6 carbon atoms inclusive, n is 2 to 24 inclusive, and the ester group substituents are bonded to the ring in an ortho- and / or meta- orientation.

8. The adhesive composition of claim 1, wherein the polyol comprises the polyol of claim 6 and the polyol of claim 7.

9. The adhesive composition of any one of claims 1 to 8, wherein the curable diol comprises a functional group selected from the group consisting of an acid functional group, a (meth)acrylate functional group, and combinations thereof.

10. The adhesive composition of any one of claims 1 to 9, wherein the first ionic liquid has hydroxyl functionality.

11. The adhesive composition of any one of claims 1 to 10, wherein the first ionic liquid is independently selected from an ionic liquid which has monol or diol functionality.

12. The adhesive composition of claim 10 or claim 11 wherein the first ionic liquid has the structurewherein: each R1comprises independently an alkyl, alicyclic, aryl, alkalicyclic, alkaryl, alicyclicalkyl, aralicyclic, or alicyclicaryl moiety, wherein such moiety may comprise one or more heteroatoms such as for example, nitrogen, oxygen, or sulfur, R1may be cyclic or aromatic and include N+in the cycle; each R2comprises independently an alkyl, alicyclic, aryl, alkalicyclic, alkaryl, alicyclicalkyl, aralicyclic, or alicyclicaryl moiety, wherein such moiety may comprise one or more heteroatoms such as for example, nitrogen, oxygen, or sulfur, R2may be cyclic or aromatic and include N+in the cycle, and further has a primary or secondary alcohol group; a is an integer of 1 to 2; andX' is an anion with the proviso that if the cation is CsHi ?N+(CH3)(CH2CH2OH)2 the X' anion is not Br-, BF4-, or -O3SCH3.

13. The adhesive composition of any one of claims 1 to 12, wherein the first ionic liquid comprises a (meth)acrylate moiety.

14. The adhesive composition of any one of claims 1 to 13, wherein the first ionic liquid is a diol and wherein the diol is incorporated into a polyurethane-based polymer backbone via the isocyanate / alcohol reaction.

15. The adhesive composition of any one of claims 1 to 14, wherein the first ionic liquid comprises a quaternary ammonium salt moiety.

16. The adhesive composition of any one of claims 1 to 15, wherein the first ionic liquid comprises two quaternary ammonium salt moieties.

17. The adhesive composition of any one of claims 1 to 14, wherein the first ionic liquid is selected from the group consisting of l-butyl-3-methylimidazolium hexafluorophosphate, trimethyl ammonium ethyl acrylate bis(trifluoromethanesulfonyl)imide, trimethyl ammonium ethyl acrylatebis(fluorosulfonyl)imide, di-methyl-butyl-ammonium ethyl acrylate bis(fluorosulfonyl)imide, di-methyl-hexyl-ammonium ethyl acrylate bis(fluorosulfonyl)imide, l-butyl-3-methylimidazolium iodide, l-butyl-3- methylimidazolium tricyanomethanide, 3-sulfopropyl acrylate N-octyl-N-methyl- imidazolium, 3-sulfopropyl acrylate N-butyl-N-methyl-imidazolium, N-vinyl- imidazolium bis(fluorosulfonyl)imide, N-vinyl imidazolium hexafluorophosphate, sulfopropyl acrylamide N-butyl-N'-methyl imidazolium, sulfopropyl acrylamide N- octyl-N'-methyl imidazolium, styrene sulfonate N-butyl-N'-methyl imidazolium, styrene sulfonate N-octyl-N'-methyl imidazolium, l-butyl-3-methylimidazolium bis(fhiorosulfonyl)imide, l-butyl-3-methylimidazolium thiocyanate, 1 -butyl- 1- methylpyrrolidinium dicyanamide, triethylsulfonium bis(trifluoromethylsulfonyl)imide, octylmethyl-bis(2-hydroxyethyl)ammonium bis(fluorosulfonyl)imide, octylmethyl- bis(2-hydroxyethyl)ammonium hexafluorophosphate, butylmethyl-bis(2- hydroxyethyl)ammonium bis(fluorosulfonyl)imide, dodecylmethyl-bis(2- hydroxyethyl)ammonium bis(fluorosulfonyl)imide, hexadecylmethyl-bis(2- hydroxyethyl)ammonium bis(fluorosulfonyl)imide, octylmethyl-bis(2- hydroxypropyl)ammonium bis(fluorosulfonyl)imide, octyldimethyl-(2- hydroxyethyl)ammonium bis(fluorosulfonyl)imide, octyldimethyl-(2- hydroxyethyl)ammonium hexafluorophosphate, l-methyl-3-[12-(3-methylimidazol-l- ium-l-yl)dodecyl]imidazol-3-ium;di-hcxafluorophosphate, and combinations thereof.

18. The adhesive composition of any one of claim 10 to 17, further comprising a second ionic liquid, wherein the second ionic liquid is a diol and wherein the diol is incorporated into a polyurethane-based polymer backbone via the isocyanate / alcohol reaction.

19. The adhesive composition of any one of claims 1 to 18 comprising:5 to 20 wt.% of the polyisocyanate;60 to 90 wt.% of the polyol;0.2 to 10 wt.% of the curable diol; and0.5 to 25 wt.% of the ionic liquid based on the parts per hundred of the base polymer.

20. The adhesive composition of any one of claims 1 to 19, further comprising an additive selected from the group consisting of a multifunctional epoxy resin, a photoinitiator, a pigment, a UV stabilizer, an antioxidant, and combinations thereof.

21. The adhesive composition of any one of claims 1 to 20, wherein the adhesive comprises a pressure-sensitive adhesive.

22. The adhesive composition of any one of claims 1 to 21, wherein the polyurethane-based polymer has a weight average molecular weight of 30,000 to 200,000 g / mol.

23. The adhesive composition of any one of claims 1 to 22, wherein the adhesive composition is a thermally curable composition, a UV-curable composition, or an e- beam curable composition.

24. An article comprising the adhesive of any one of claims 1 to 23.

25. The article of claim 24, wherein the article is a transfer tape or a double-sided tape.

26. An article comprising the adhesive of any one of claims 1 to 23, the article comprising an adhesive layer, wherein the adhesive layer has a thickness of 10 to 1000 microns, optionally 50 to 300 microns, or optionally 75 to 200 microns.

27. A method of separating adhered substrates the method comprising: obtaining adhered substrates, wherein adhesion is accomplished using the adhesive composition of any one of claims 1 to 23; applying an electric potential to the substrates.

28. The method of claim 27, wherein the peak stress required to debond the substrates is reduced by at least 50%, at least 60%, or at least 70% after applying the electric potential to the substrates.

29. The method of claim 27 or claim 28, wherein applying the electric potential is for at least 5 minutes at 50V.

30. The method of any one of claims 27 to 30, wherein the adhered substrates are exposed to artificial sweat before application of the potential.

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