Adhesive system including tape having foam support layer

Abstract

An adhesive system comprising a tape and an activator, the activator comprising an oxidizer and being liquid at ambient temperature and pressure, the tape comprising a curable adhesive free-standing film adjacent to a curable foam support layer, the curable adhesive free-standing film comprising a) a film-forming polymer or oligomer, b) a species comprising an unsaturated free-radically polymerizable group, which may be a) or a species other than a), and c) a transition metal cation.

Description

[Background technology]

[0001] Curable adhesive films and tapes including such films are known. Such films and tapes are typically used with species that activate the cure of the adhesive on contact to produce a structural adhesive bond. The adhesive film may be a pressure sensitive adhesive prior to curing, and the tape may include a foam support layer, but additional adhesive systems with foam support layers having improved strength and gap spanning capabilities are needed. Summary of the Invention

[0002] In one aspect, there is provided an adhesive system comprising a tape and an activator for adhering a curable adhesive free-standing film to a substrate, the activator being liquid at room temperature and pressure and comprising an oxidizer, the tape comprising a curable adhesive free-standing film adjacent to a curable foam support layer, the curable adhesive free-standing film comprising a) a film-forming polymer or oligomer, b) a species comprising an unsaturated free-radically polymerizable group, which may be a) or a species other than a), and c) a transition metal cation.

[0003] In another aspect, there is provided an adhesive system as described above, wherein the curable adhesive free-standing film is a first curable adhesive free-standing film, and the tape further comprises a second curable adhesive free-standing film, the second curable adhesive free-standing film comprising components comprising: a') a film-forming polymer or oligomer; b') a species comprising an unsaturated free-radically polymerizable group, which can be a') or a species other than a'); and c') a transition metal cation, and the second curable adhesive free-standing film is adjacent to a surface of the curable foam support layer opposite the first curable adhesive free-standing film.

[0004] Also provided are embodiments that include a barrier film support layer in addition to the curable foam support layer.

[0005] In another aspect, the present disclosure provides a method for producing a bonded article. The method includes applying the above-mentioned tape to a first substrate, applying the described activator to a second substrate, and contacting the tape on the first substrate with the activator on the second substrate to bond the first substrate and the second substrate. Other methods of using the adhesive system of the present disclosure are also described.

[0006] The term "curable" means capable of crosslinking when contacted with an activator. Both the foam support layer and the adhesive free-standing film are curable in that they are crosslinkable, although they may be crosslinkable by the same or different mechanisms.

[0007] The term adjacent, as used throughout this specification, refers to two superimposed layers within a tape or within a structure comprising a tape, an activator, and one or more substrates that are arranged directly adjacent to one another, i.e., abutting one another and typically in direct contact with one another.

[0008] Of two adjacent layers, one layer may be "carried on" the other layer, or one layer may be "directly bonded" to the other layer. In the former case, the layers are typically made in one step, for example, occurring in a coating or coextrusion process. In the latter case, the layers are typically made in two or more steps, for example, occurring in a lamination process.

[0009] The term "film-forming" means, in some embodiments, capable of forming a continuous and coherent film, which may result from one or more of solidification, hardening, drying, or solvent removal of a melt, solution, suspension, etc.

[0010] The term "free-standing film" means a film that is solid at ambient temperature and pressure and has mechanical integrity independent of contact with any supporting material (specifically excluding surface coatings that are dried or cured in place, such as liquids, paints or primers, and surface coatings that do not have independent mechanical integrity).

[0011] The term "hot melt processable" in the context of one of the polymer-containing layers or films described herein means that the polymer-containing composition contains little or no conventional solvents that can be hot melt processed under conventional conditions (in various embodiments, conventional solvents may be less than 5 weight percent, less than 3 weight percent, less than 1 weight percent, less than 0.5 weight percent, less than 0.1 weight percent, or less than 0.01 weight percent), where hot melt processes include hot melt blending and extrusion.

[0012] The term "(meth)acrylate" includes, individually and collectively, methacrylates and acrylates.

[0013] The term "monomer unit" of a polymer or oligomer is a segment of the polymer or oligomer that is derived from a single monomer.

[0014] The term "normal temperature and pressure" or "NTP" refers to a temperature of 20° C. (293.15 K, 68° F.) and an absolute pressure of 1 atmosphere (14.696 psi, 101.325 kPa).

[0015] The term "pendant" in the context of a functional group of a polymer or oligomer is a functional group that does not form part of the backbone of the polymer or oligomer and is not an end group of the polymer.

[0016] The term "structural adhesive" refers to an adhesive that bonds by irreversible cure, typically having a strength when bonded to its intended substrate of at least 4.52 MPa (655 psi), more typically at least 5.36 MPa (777 psi), and in some embodiments at least 6.29 MPa (912 psi), measured as the break stress (peak stress) using the Dynamic Shear Adhesion Test described in the Examples section.

[0017] The term "glass transition temperature" or "Tg" refers to the temperature at which a material changes from a glass-like state to a rubber-like state. In this context, the term "glass-like" means that the material is hard and brittle (and therefore breaks relatively easily), and the term "rubber-like" means that the material is elastic and flexible. For polymeric materials, the Tg is the critical temperature that separates glass-like from rubber-like behavior. When a polymeric material is at a temperature below its Tg, the material is essentially frozen, so large-scale molecular motion is very limited. On the other hand, when a polymeric material is at a temperature above its Tg, molecular motion on the scale of repeat units occurs and the material becomes soft and rubber-like. Any reference herein to the Tg of a monomer refers to the Tg of a homopolymer formed from that monomer. The glass transition temperature of a polymeric material is often measured using methods such as Dynamic Mechanical Analysis ("DMA") or Differential Scanning Calorimetry (e.g., Modulated Differential Scanning Calorimetry). Alternatively, the glass transition of a polymeric material can be calculated using the Fox equation if the amount and Tg of each monomer used to form the polymeric material are known.

[0018] The term "alkyl" refers to a monovalent group that is a saturated hydrocarbon. An alkyl can be linear, branched, cyclic, or a combination thereof and typically has 1 to 32 carbon atoms. Unless otherwise specified, an alkyl group contains 1 to 25, 1 to 20, 1 to 18, 1 to 12, 1 to 10, 1 to 8, 1 to 6, or 1 to 4 carbon atoms. Examples of alkyl groups include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, n-hexyl, cyclohexyl, n-heptyl, n-octyl, 2-ethylhexyl, 2-octyl, and 2-propylheptyl.

[0019] The term "aryl" refers to a monovalent group that is aromatic and optionally carbocyclic. An aryl has at least one aromatic ring. Any additional rings may be unsaturated, partially saturated, saturated, or aromatic. Optionally, the aromatic ring may have one or more additional carbocyclic rings fused to the aromatic ring. Unless otherwise specified, an aryl group typically contains 6 to 30 carbon atoms. In some embodiments, an aryl group contains 6 to 20, 6 to 18, 6 to 16, 6 to 12, or 6 to 10 carbon atoms. Examples of aryl groups include phenyl, naphthyl, biphenyl, phenanthryl, and anthracyl.

[0020] The term "aralkyl" refers to a monovalent group that is an alkyl substituted with an aryl group, such as, for example, a benzyl group. The term "alkaryl" refers to a monovalent group that is an aryl group substituted with an alkyl group, such as, for example, a tolyl group. Unless otherwise specified, the alkyl portion in either group often has 1-10 carbon atoms, 1-6 carbon atoms, or 1-4 carbon atoms, and the aryl portion often has 6-20 carbon atoms, 6-18 carbon atoms, 6-16 carbon atoms, 6-12 carbon atoms, or 6-10 carbon atoms.

[0021] The term "alkylene" refers to a divalent group that is a radical of an alkane, and includes groups that are straight chain, branched chain, cyclic, bicyclic, or combinations thereof. Unless otherwise specified, alkylene groups typically have 1 to 30 carbon atoms. In some embodiments, alkylene groups have 1 to 20 carbon atoms, 1 to 10 carbon atoms, 1 to 6 carbon atoms, or 1 to 4 carbon atoms. Examples of "alkylene" groups include methylene, ethylene, propylene, 1,4-butylene, 1,4-cyclohexylene, and 1,4-cyclohexyldimethylene.

[0022] The term "arylene" refers to a divalent group that is aromatic and optionally carbocyclic. An arylene has at least one aromatic ring. Optionally, the aromatic ring can have one or more additional carbocyclic rings fused to the aromatic ring. Any additional rings can be unsaturated, partially saturated, or saturated. In some embodiments, an arylene group has up to 5 rings, up to 4 rings, up to 3 rings, up to 2 rings, or 1 aromatic ring. For example, an arylene group can be phenylene. Unless otherwise specified, an arylene group often has 6 to 20 carbon atoms, 6 to 18 carbon atoms, 6 to 16 carbon atoms, 6 to 12 carbon atoms, or 6 to 10 carbon atoms.

[0023] The term "aralkylene" refers to a divalent group that is an alkylene group substituted with an aryl group or an alkylene group bonded to an arylene group. The term "alkarylene" refers to a divalent group that is an arylene group substituted with an alkyl group or an arylene group bonded to an alkylene group. Unless otherwise specified, the alkyl or alkylene moieties in either group typically have 1 to 20 carbon atoms, 1 to 10 carbon atoms, 1 to 6 carbon atoms, or 1 to 4 carbon atoms. Unless otherwise specified, the aryl or arylene moieties in either group typically have 6 to 20 carbon atoms, 6 to 18 carbon atoms, 6 to 16 carbon atoms, 6 to 12 carbon atoms, or 6 to 10 carbon atoms.

[0024] The term "hydrocarbyl" includes aryl and alkyl.

[0025] As used herein, the term "or" is generally used in its ordinary sense including "and / or" unless the content clearly dictates otherwise.

[0026] As used herein, the term "and / or" is used to indicate that either or both of the stated things can occur; for example, A and / or B includes (A and B) and (A or B).

[0027] As used herein, the term "room temperature" refers to a temperature in the range of 20°C to 25°C.

[0028] As used herein, the term "comprising" and variations thereof do not have a limiting meaning when these terms are described in the specification and claims. Such terms will be understood to imply the inclusion of the described step or element or group of steps or elements, but not the exclusion of any other step or element or group of steps or elements. "Consisting of" means including and limiting everything before the phrase "consisting of". Thus, the phrase "consisting of" indicates that the recited elements are necessary or mandatory, and no other elements may be present. "Consisting essentially of" means including everything before the phrase, and limited to other elements that do not interfere with or contribute to the activity or action specified in this disclosure for those recited elements. Thus, the phrase "consisting essentially of" indicates that the recited elements are necessary or mandatory, but other elements are optional and may or may not be present depending on whether they substantially affect the activity or action of the recited elements. Any element or combination of elements described herein with open-ended language (e.g., comprise and its derivatives) shall be deemed to be further described with closed-ended language (e.g., consist and its derivatives) and partially closed-ended language (e.g., consist essentially and its derivatives).

[0029] The words "preferred" and "preferably" refer to embodiments of the present disclosure that may provide certain benefits, under particular circumstances. However, other embodiments may also be preferred, under the same or other circumstances. Moreover, the recitation of one or more preferred embodiments does not imply that other claims are not useful, and is not intended to exclude other embodiments from the scope of the present disclosure.

[0030] In this application, terms such as "a," "an," and "the" are not intended to refer to only a singular entity, but include general classes, specific examples of which may be used for illustration. The terms "a," "an," and "the" are used interchangeably with the term "at least one." The phrases "at least one of" and "including at least one of" following a list refer to any one of the items in the list, and any combination of two or more items in the list.

[0031] Also, all numbers herein are intended to be modified by the term "about," and in certain embodiments, preferably by the term "exactly." When used herein in the context of a measured quantity, the term "about" refers to the variation in the measured quantity as would be expected by one of ordinary skill in the art making the measurement and exercising a level of care commensurate with the purpose of the measurement and the precision of the measuring device used. As used herein, a "up to" number (e.g., up to 50) is inclusive of that number (e.g., 50).

[0032] Also herein, the recitation of numerical ranges by endpoints includes all numbers subsumed within that range, as well as the endpoints thereof (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, 5, etc.) and any subranges (e.g., 1 to 5 includes 1 to 4, 1 to 3, 2 to 4, etc.).

[0033] The terms "in the range" or "within a range" (and similar descriptions) include the endpoints of the stated range.

[0034] References throughout this specification to "one embodiment," "an embodiment," "particular embodiment," or "some embodiments" mean that the particular feature, configuration, composition, or characteristic described in connection with an embodiment is included in at least one embodiment of the disclosure. Thus, the appearances of such phrases in various places throughout this specification do not necessarily refer to the same embodiment of the disclosure. Furthermore, the particular features, configurations, compositions, or characteristics may be combined in any suitable manner in one or more embodiments.

[0035] The above summary of the disclosure is not intended to describe each of the disclosed embodiments or all implementations of the disclosure. The following description illustrates exemplary embodiments in more detail. In several places throughout the application, guidance is provided through lists of examples, which can be used in various combinations. In each instance, the listed list serves only as a representative group and should not be construed as an exclusive list. Thus, the scope of the disclosure should not be limited to the specific exemplary structures described herein, but rather extends at least to the structures described by the language of the claims and equivalents of those structures. Any of the elements expressly described herein as alternatives can be expressly included or excluded from the claims in any combination as desired. Various theories and possible mechanisms may be discussed herein, but in no event should such discussion be construed as limiting the subject matter that can be claimed. [Brief description of the drawings]

[0036] [Figure 1] FIG. 1 is a cross-sectional view of one embodiment of a tape according to the present disclosure. [Diagram 2] FIG. 1 is a cross-sectional view of one embodiment of a double-sided tape having two curable adhesive free-standing film layers according to the present disclosure. [Diagram 3]3 is a cross-sectional view of one embodiment of a structure using a double-sided tape of the type shown in FIG. 2 according to the present disclosure, where the curable and curable layers are referenced by the same numerical designation. Structure 300 includes substrate 320, activator 370, tape 310 (including curable or cured adhesive layer 340, curable or cured foam support layer 350, curable or cured adhesive layer 360), activator 380, and substrate 330. [Figure 4] FIG. 1 is a cross-sectional view of one embodiment of a double-sided tape having a single curable adhesive free-standing film layer according to the present disclosure. [Diagram 5] 1 is a cross-sectional view of one embodiment of a double-sided, multi-layer tape having a barrier film support layer according to the present disclosure. [Figure 6] 1 shows migration data of crosslinker from FTIR migration test. [Figure 7] 3 is a cross-sectional view of another embodiment of a structure using double-sided tape of the type shown in FIG. 2 according to the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0037] The present disclosure provides an adhesive system including a tape and an activator. The tape includes a curable adhesive free-standing film adjacent to a curable foam support layer. The activator is liquid at ambient temperature and pressure and includes an oxidizer. The activator is used to initiate curing of the curable adhesive free-standing film while in contact with a substrate, thereby forming a structural adhesive bond between the tape and the substrate.

[0038] The adhesive system does not require mixing of liquid components for use, rather, an activator is applied to a substrate and the activator-coated substrate is contacted with the curable adhesive free-standing film of the tape. Upon contact with the activator-coated substrate, the curable adhesive film of the tape of the present disclosure begins to cure, resulting in a structural adhesive bond. In some embodiments of the adhesive system, curing can be achieved at ambient temperature and pressure without heat or autoclave. Similarly, in some embodiments of the adhesive system, curing can be achieved without UV or other radiation treatment, and the cure propagates well to areas inaccessible to radiation curing. In some embodiments of the adhesive system, the components of the adhesive system do not need to be refrigerated or stored in the dark.

[0039] As shown in FIG. 1 (not to scale), an exemplary tape 110 includes a curable adhesive free-standing film 140 (having two major surfaces 142 and 144) adjacent to a curable foam support layer 150 (having two major surfaces 152 and 154). The curable adhesive free-standing film includes a) a film-forming polymer or oligomer; b) a species that includes an unsaturated free-radically polymerizable group, which can be a) or a species other than a); and c) a transition metal cation. In certain embodiments, b) is a) in the curable adhesive free-standing film. In certain embodiments, b) is a species other than a), where a) does not include an unsaturated free-radically polymerizable group.

[0040] In the tapes described herein, the curable adhesive free-standing film 140 may be carried on a curable foam support layer (e.g., major surface 152 of curable foam support layer 150 in FIG. 1). That is, the layer is typically made in one step, such as occurs in a coating or coextrusion process. Alternatively, the curable adhesive free-standing film 140 is directly bonded to the curable foam support layer (e.g., major surface 152 of curable foam support layer 150 in FIG. 1). That is, the layer is typically made in two or more steps, such as occurs in a lamination process. Such procedures are well known in the preparation of tapes. However made, the major surface 144 of the curable adhesive free-standing film 140 is adjacent to the major surface 152 of the curable foam support layer 150.

[0041] In certain embodiments, the tape is a double-sided tape having one curable adhesive free-standing film adjacent to each major surface of the curable foam support layer (i.e., a second curable adhesive free-standing film adjacent to the surface opposite the first curable adhesive free-standing film). Thus, in this embodiment, the first curable adhesive free-standing film is adjacent to the first major surface of the curable foam support layer and the second curable adhesive free-standing film is adjacent to the second major surface of the curable foam support layer.

[0042] 2 (not to scale), the exemplary double-sided tape 210 includes a first curable adhesive free-standing film 240 (having two major surfaces 242 and 244) and a second curable adhesive free-standing film 260 (having two major surfaces 262 and 264), each of which is adjacent to an opposing surface of a curable foam support layer 250 (having two major surfaces 252 and 254). More specifically, the first major surfaces 242 and 262 form the outer adhesive side of the double-sided tape 210, with the second major surface 244 of the first adhesive free-standing film 240 adjacent to the first major surface 252 of the foam support layer 250 and the second major surface 264 of the second adhesive free-standing film 260 adjacent to the second major surface 254 of the foam support layer 250.

[0043] The second curable adhesive free-standing film comprises a') a film-forming polymer or oligomer, b') a species comprising an unsaturated free-radically polymerizable group, which can be a') or a species other than a'), and c') a transition metal cation. The components of the first and second curable adhesive free-standing films can be the same or different. In certain embodiments, b') is a') in the curable adhesive free-standing film. In certain embodiments, b') is a species other than a'), where a') does not comprise an unsaturated free-radically polymerizable group.

[0044] 2, a first curable adhesive freestanding film 240 is supported on a first major surface 252 of a curable foam support layer 250, and a second curable adhesive freestanding film 260 is supported on a second major surface 254 of a curable foam support layer 250. In another embodiment of FIG. 2, a first curable adhesive freestanding film 240 is bonded directly to the first major surface 252 of a curable foam support layer 250, and a second curable adhesive freestanding film 260 is bonded directly to the second major surface 254 of a curable foam support layer 250.

[0045] Such adhesive tapes are used with an activator, which includes an oxidizing agent, that initiates curing of the curable adhesive film and the curable foam backing layer upon contact between the activator and the curable adhesive film. Typically, the oxidizing agent of the activator migrates to the curable adhesive film and the curable foam backing layer, thereby initiating curing of both the curable adhesive film and the curable foam backing layer.

[0046] In use, the activator is typically applied to a substrate, dried, and a curable adhesive free-standing film of the tape is applied to the activator-coated substrate. Referring to FIG. 3 (not to scale), in one embodiment, a structure 300 includes a tape 310 and substrates 320 and 330. The substrate can be any suitable material. Suitable substrate materials can include metals, such as aluminum, titanium, steel, and the like. Suitable substrate materials can include polymeric materials, such as polyolefins, polyethylene, polypropylene, polystyrene, poly(meth)acrylates, polyurethanes, natural or synthetic rubbers, polydienes, and the like. Suitable substrate materials can include natural materials, such as wood, stone, and the like, or derivatives, such as composite boards or concrete, and the like. Suitable substrate materials can include glass or ceramic materials. When two substrates are bonded to each other using the adhesive system of the present disclosure, they are selected independently.

[0047] As shown in FIG. 3, an activator according to the present disclosure is applied to a first substrate 320 and allowed to dry to form an activator layer 370 adjacent to the first substrate 320. Similarly, an activator according to the present disclosure is applied to a second substrate 330 and allowed to dry to form an activator layer 380 adjacent to the second substrate 330. The activators used to form the activator layers 370 and 380 may be the same or different. A double-sided tape 310 according to one embodiment of the present disclosure, including curable adhesive free-standing films 340 and 360 adjacent to a single curable foam support layer 350, is applied to the activator layers 370 and 380 such that the curable adhesive free-standing films 340 and 360 are in contact with the activator layers 370 and 380, respectively. In some embodiments, during use, the assembly is held by an external force, e.g., a clamp, until the curable adhesive film cures, while in other embodiments, the tackiness of the tape alone holds the assembly until curing. The tape cures to form a cured structural adhesive layer from the curable adhesive free-standing films 340 and 360 adjacent to the activator layers 370 and 380, and the cured foam support layer 350. The activator layers 370 and 380 can be cured or simply dried in a final structure comprising two substrates bonded together by double-sided tape using a structural adhesive bond.

[0048] As used herein, "curable" means capable of crosslinking when contacted with an activator. Both the foam support layer and the adhesive free-standing film are curable in that they are crosslinkable, although they may be crosslinkable by the same or different mechanisms.

[0049] The curable adhesive free-standing film comprises a film-forming polymer or oligomer. It also comprises a crosslinkable species (i.e., a crosslinking agent). Such a crosslinkable species may be a species that comprises an unsaturated free-radically polymerizable group, which may be a film-forming polymer or oligomer or a species other than a film-forming polymer or oligomer. That is, the crosslinkable species may be a film-forming polymer or oligomer if it comprises an unsaturated free-radically polymerizable group. Alternatively, the crosslinkable species may be different from the film-forming polymer or oligomer.

[0050] In certain embodiments, the curable foam support layer comprises a base polymer or oligomer and a crosslinker within the curable foam support layer (using a mechanism similar to that of the curable adhesive free-standing film). Such a crosslinker can be a film-forming polymer or oligomer or a species that contains unsaturated free-radically polymerizable groups, which can be a species other than a film-forming polymer or oligomer. That is, the base polymer or oligomer of the curable foam support layer can be the same as the film-forming polymer or oligomer of the curable adhesive free-standing film, which may or may not contain unsaturated free-radically polymerizable groups.

[0051] If the base polymer or oligomer of the curable foam support layer does not contain unsaturated free-radically polymerizable groups, such groups may be provided by separate species within the curable foam support layer (as described herein for the curable adhesive free-standing film) or by species that migrate into the curable foam support layer. Thus, in certain embodiments, the curable foam support layer comprises a base polymer or oligomer that can accept a crosslinking agent that is transferable to the curable foam support layer. Typically, in such embodiments, the crosslinking agent migrates from the curable adhesive free-standing film.

[0052] The crosslinker of the curable foam support layer may be the same as or different from the crosslinker (i.e., the species containing unsaturated free radically polymerizable groups) of the curable adhesive free-standing film. In certain embodiments, the crosslinker of the curable foam support layer is the same as the species containing unsaturated free radically polymerizable groups of the curable adhesive free-standing film. In certain embodiments, the crosslinker of the curable foam support layer is the species containing unsaturated free radically polymerizable groups of the curable adhesive free-standing film that migrates to the curable support layer.

[0053] Thus, in the present disclosure, the curable free-standing film includes a crosslinking species therein prior to activator-initiated cure, while the curable foam support layer may include a crosslinking species therein prior to activator-initiated cure or the curable foam support layer may be capable of receiving a migratory crosslinking species prior to activator-initiated cure. In this context, the crosslinking species and cure process are distinct from any crosslinking agents, such as crosslinking monomers, used during preparation that includes crosslinking of the adhesive free-standing film and / or curable foam support layer prior to formation of the tape.

[0054] The curable foam support layer of the tapes of the present disclosure is in the form of a foam that can be closed cell, open cell, syntactic, or non-syntactic foam. Such foams can be made using chemical blowing agents, physical blowing agents, mechanical foaming processes, etc. In certain embodiments, the curable foam support layer comprises a blowing agent and the same ingredients as the curable adhesive free-standing film.

[0055] Preferably, the tape is a multi-layer tape. In certain embodiments, the tape of the present disclosure may include one or more curable self-supporting adhesive films (having two major surfaces) and one or more curable foam support layers (having two major surfaces). In certain embodiments, the multi-layer tape of the present disclosure also includes one or more barrier film support layers (having two major surfaces), one or more conventional adhesive layers (having two major surfaces) that include an adhesive that does not cure when contacted with an activator, and a tape backing material and a release liner that are commonly used in multi-layer tapes.

[0056] For example, a double-sided tape of the present disclosure may include only one curable adhesive free-standing film and only one curable foam support layer, but may include a second adhesive layer that does not cure upon contact with an activator.

[0057] As shown in FIG. 4 (not to scale), the exemplary tape 410 includes a curable adhesive free-standing film 440 and a second adhesive layer 460, which may be any of a variety of conventional adhesives (e.g., pressure-sensitive adhesives) that do not cure upon contact with an activator, each adjacent to an opposing surface of a curable foam support layer 450. Exemplary conventional adhesives include pressure-sensitive adhesives that are tacky and bond instantly when pressure is applied, thermoplastic adhesives that bond when heat and pressure are applied and may be thermally reversible, or thermosetting adhesives that bond when subjected to heat and pressure for a period of time and cause some irreversible chemical reaction. In some embodiments, the second adhesive layer 460 is a conventional pressure-sensitive adhesive that achieves a lower adhesive strength than the curable adhesive free-standing film 440 applied to an activator on a substrate.

[0058] One or more barrier film support layers (i.e., barrier layers) may be used in the multilayer tapes of the present disclosure to provide a barrier against, for example, migration of crosslinkable species. For example, a tape of the type described in Figure 1 may further include a barrier film support layer adjacent to a major surface of the curable foam support layer opposite a major surface of the curable adhesive freestanding film, such that a three-layer tape is formed comprising curable adhesive / curable foam / barrier.

[0059] In another example, a tape of the type described in Figure 2 can further include a barrier film support layer disposed between the curable foam support layer and one of the curable adhesive free-standing films. In this embodiment, the first curable adhesive free-standing film is adjacent to the curable foam support layer, which is adjacent to the barrier film support layer, and the barrier film support layer is adjacent to the second curable adhesive free-standing film, such that a four-layer tape is formed that includes curable adhesive / curable foam / barrier / curable adhesive. Stated another way, the first curable adhesive free-standing film is adjacent to the curable foam support layer, the barrier film support layer is adjacent to the surface of the curable foam support layer opposite the first curable adhesive free-standing film, and the second curable adhesive free-standing film is adjacent to the surface of the barrier film support layer opposite the curable foam support layer.

[0060] In another example, a multi-layer tape can be prepared from two tapes of the type described in FIG. 1 with a barrier film support layer disposed between the curable foam layers of the two tapes such that a five-layer tape is formed comprising curable adhesive / curable foam / barrier / curable foam / curable adhesive.

[0061] In yet another example, a multi-layer tape may be prepared from two double-sided tapes of the type shown in Figure 2 with a barrier film backing layer disposed between the two tapes such that a seven-layer tape is formed that includes curable adhesive / curable foam / curable adhesive / barrier / curable adhesive / curable foam / curable adhesive. That is, in such an embodiment, a first curable adhesive freestanding film, a first curable foam backing layer, a second curable adhesive freestanding film, a barrier film backing layer, a third curable adhesive freestanding film, a second curable foam backing layer, and a fourth curable adhesive freestanding film are stacked in sequence.

[0062] More specifically, as shown in FIG. 5 (not to scale), tape 510 includes a first curable adhesive freestanding film 540 and a second curable adhesive freestanding film 560, each adjacent to opposing major surfaces of a first curable foam support layer 550. Tape 510 also includes a third curable adhesive freestanding film 540' and a fourth curable adhesive freestanding film 560', each adjacent to opposing major surfaces of a second curable foam support layer 550'. Curable adhesive freestanding film 560 has a surface 562 adjacent a first surface 592 of barrier film support layer 590, and curable adhesive freestanding film 560' has a surface 562' adjacent a second surface 594 of barrier film support layer 590. Barrier film support layer 590 prevents migration of crosslinkable species across it. Thus, different curing mechanisms and curable components can be used on both sides of the barrier layer (ie, in layers 540 / 550 / 560 compared to layers 540' / 550' / 560').

[0063] The multilayer tapes of the present disclosure may include two or more curable adhesive free-standing films having the same or different (i.e., independently selected) components. The multilayer tapes of the present disclosure may include two or more curable foam support layers having the same or different (i.e., independently selected) components. The multilayer tapes of the present disclosure may include two or more barrier film support layers having the same or different (i.e., independently selected) components. The structures of the present disclosure may include two or more activator layers having the same or different (i.e., independently selected) components.

[0064] The curable or cured adhesive free standing adhesive film can be of any suitable thickness. In some embodiments, the thickness is at least 20 micrometers, at least 25 micrometers, at least 50 micrometers, at least 100 micrometers, at least 200 micrometers, at least 250 micrometers, at least 300 micrometers, or at least 350 micrometers. In some embodiments, the thickness is no more than 2000 micrometers, no more than 1000 micrometers, or no more than 500 micrometers.

[0065] The curable or cured foam support layer can be of any suitable thickness. In some embodiments, the thickness is at least 20 micrometers, at least 25 micrometers, at least 50 micrometers, at least 100 micrometers, at least 200 micrometers, at least 250 micrometers, at least 300 micrometers, or at least 350 micrometers. In some embodiments, the thickness is no more than 2000 micrometers, no more than 1000 micrometers, or no more than 500 micrometers.

[0066] The barrier film support layer can be of any suitable thickness. In some embodiments, the thickness is at least 10 micrometers, at least 15 micrometers, at least 20 micrometers, at least 25 micrometers, or at least 50 micrometers. In some embodiments, the thickness is no more than 2000 micrometers, no more than 1000 micrometers, or no more than 500 micrometers.

[0067] The activator layer can be of any suitable thickness. In some embodiments, the thickness is at least 1 micrometer, at least 2 micrometers, at least 3 micrometers, at least 4 micrometers, or at least 5 micrometers. In some embodiments, the thickness is no more than 20 micrometers, no more than 15 micrometers, or no more than 10 micrometers.

[0068] Tapes of the present disclosure preferably have an extensibility of at least 0.5 mils (12.7 micrometers) according to the Lang Test described in the Examples section.

[0069] Curable adhesive free standing film The curable adhesive free-standing film (i.e., the curable adhesive film) of the tapes of the present disclosure comprises a film-forming polymer or oligomer, a species that comprises unsaturated free-radically polymerizable groups, which can be a film-forming polymer or oligomer (i.e., a reactive polymer or oligomer that comprises unsaturated free-radically polymerizable groups) or a species other than a film-forming polymer or oligomer, and a transition metal cation.

[0070] In some embodiments, the unsaturated free radically polymerizable groups are selected from ethylenically unsaturated groups, including vinyl-containing groups, such as (meth)acrylate groups.

[0071] The curable adhesive film is typically a solid at room temperature.

[0072] In some embodiments, the curable free-standing film comprises a blend of a reactive polymer or oligomer that comprises unsaturated, typically pendant, free-radically polymerizable groups, and a transition metal cation. In some embodiments, the curable free-standing film comprises a blend of a film-forming polymer or oligomer, a reactive species that comprises unsaturated, free-radically polymerizable groups, and a transition metal cation. In certain embodiments, the curable free-standing film also comprises a redox accelerator.

[0073] In some embodiments, the curable adhesive film has an outer surface, i.e., the surface facing the substrate, that includes embossed air release channels that can aid in the escape of air during application of the outer surface to the substrate. The channels and their manufacturing method may be as taught in U.S. Pat. No. 6,655,281 (Jordan et al.). Such channels serve a unique purpose in the use of the articles of the present disclosure. By allowing the escape of trapped air bubbles, the air release channels may help improve contact with an activator or second film that initiates the curing of the curable adhesive film. When an adhesive film or tape has one embossed and non-embossed surface, the non-embossed surface may be placed on the first substrate, and then the second substrate may be contacted with the embossed surface. This approach may be particularly useful when two rigid substrates are to be bonded, as it allows for air release and conformability to uneven surfaces despite the inflexibility of the substrates.

[0074] The curable adhesive film can be made using conventional techniques, such as solution coating onto a web. In a preferred embodiment, the curable adhesive film is hot melt processable and made by a hot melt process. Hot melt processing, such as hot melt blending or hot melt extrusion, can be accomplished by any suitable means, including those disclosed in U.S. Patent Application Publication No. 2013 / 0184394(A1) (Satrijo et al.).

[0075] Film-forming polymer or oligomer In some embodiments, the film-forming polymer or oligomer is a poly(meth)acrylate polymer or oligomer. Other examples of film-forming polymers or oligomers include aromatic or aliphatic polyurethanes (including polymers made with aliphatic or aromatic diols, polyamides, saturated and unsaturated polyesters (e.g., polybutylene terephthalate, polyethylene terephthalate, polyglycolic acid, polylactic acid, poly-2-hydroxybutyrate, polycaprolactone, and combinations containing maleic acid repeat units); polyethers (e.g., polyacetals and their copolymers, polyphenylene oxides, polyetherketones, polyetheretherketones); natural and synthetic rubbers (e.g., polyisoprene, polychloroprene, nitrile rubber, butadiene-based rubber); alkyds; phenolic resins (e.g., novolacs and resols); amino resins (e.g., urea-formaldehyde resins, melamine-formaldehyde resins, and melamine-urea copolymer resins); epoxies (e.g., those made from adducts using bisphenol A, or telechelic amino resins capped with oxirane functional groups), and the like. In some embodiments, the film-forming polymer or oligomer is a (meth)acrylate-functional polymer, such as those made by adding (meth)acrylate end groups to a polyester, polyurethane, polybutadiene, or polyether polymer.

[0076] In some embodiments, the film-forming polymer or oligomer of the curable adhesive free-standing film is a poly(meth)acrylate polymer or oligomer.

[0077] In certain embodiments, the curable adhesive films are pressure sensitive adhesives before they are cured in contact with an activator. Thus, they can hold a substrate in place without clamps or other supports under shop or factory conditions, even before they are cured. A preferred such pressure sensitive adhesive comprises a first (meth)acrylate copolymer, the first (meth)acrylate copolymer comprising 0.1 weight percent to 12 weight percent (meth)acrylic acid monomer units, based on the weight of the first (meth)acrylate copolymer, and a second (meth)acrylate copolymer comprising 15 weight percent to 40 weight percent (meth)acrylic acid monomer units, based on the weight of the second (meth)acrylate copolymer.

[0078] In such embodiments in which the curable adhesive film is a pressure sensitive adhesive, the first (meth)acrylate copolymer and / or the second (meth)acrylate copolymer, preferably the first (meth)acrylate copolymer and the second (meth)acrylate copolymer, contain as main monomer units methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl acrylate, isobutyl acrylate, tert-butyl (meth)acrylate, n-pentyl (meth)acrylate, iso-pentyl (meth)acrylate, n-hexyl (meth)acrylate, iso-hexyl (meth)acrylate, cyclohexyl (meth)acrylate, phenyl (meth)acrylate, octyl ...butyl acrylate, isobutyl acrylate, tert-butyl (meth)acrylate, n-pentyl (meth)acrylate, iso-pentyl (meth)acrylate, n-hexyl (meth)acrylate, iso-hexyl (meth)acrylate, ethyl (meth)acrylate, n-butyl acrylate, isobutyl acrylate, tert-butyl (meth)acrylate, n-butyl acrylate, isobutyl acrylate, tert-butyl (meth)acrylate, n-butyl acrylate, and any combination or mixture thereof.

[0079] In an exemplary embodiment, the first (meth)acrylate copolymer and / or the second (meth)acrylate copolymer, preferably the first (meth)acrylate copolymer and the second (meth)acrylate copolymer, comprise as the main monomer unit a linear or branched alkyl (meth)acrylate ester monomer unit selected from the group consisting of 2-ethylhexyl (meth)acrylate, 2-propylheptyl (meth)acrylate, iso-octyl (meth)acrylate, and any combination or mixture thereof. In yet another exemplary embodiment, the first (meth)acrylate copolymer and / or the second (meth)acrylate copolymer, preferably the first (meth)acrylate copolymer and the second (meth)acrylate copolymer, comprise as the main monomer unit a 2-ethylhexyl (meth)acrylate monomer.

[0080] In certain embodiments, a first (meth)acrylate copolymer for use herein has a Tg of 0° C. or less and a second (meth)acrylate copolymer for use herein has a Tg above 0° C. In certain embodiments, the second (meth)acrylate copolymer has a Tg of 100° C. or less, 80° C. or less, 60° C. or less, 50° C. or less, 45° C. or less, or even 40° C. or less.

[0081] In certain embodiments, the first (meth)acrylate copolymer has a Tg of -70°C to 0°C, -70°C to -10°C, -60°C to -10°C, -60°C to -20°C, -60°C to -30°C, -55°C to -35°C, or -50°C to -40°C. In certain embodiments, the second (meth)acrylate copolymer has a Tg of 2°C to 100°C, 2°C to 80°C, 2°C to 60°C, 2°C to 50°C, 2°C to 45°C, 5°C to 45°C, 5°C to 40°C, 5°C to 35°C, or 10°C to 30°C.

[0082] In certain embodiments, the pressure-sensitive adhesive composition of the curable adhesive film of the present disclosure comprises 65 to 99 weight percent, 70 to 95 weight percent, 75 to 95 weight percent, 75 to 90 weight percent, or even 75 to 85 weight percent of the first (meth)acrylate copolymer, where the weight percentages are based on the total weight of the pressure-sensitive adhesive composition.

[0083] In certain embodiments, the pressure-sensitive adhesive composition of the curable adhesive film of the present disclosure comprises from 1 to 35 weight percent, from 1 to 30 weight percent, from 2 to 25 weight percent, from 3 to 25 weight percent, from 3 to 20 weight percent, from 4 to 20 weight percent, or even from 4 to 15 weight percent of the second (meth)acrylate copolymer, where the weight percentages are based on the total weight of the pressure-sensitive adhesive composition.

[0084] Exemplary pressure-sensitive adhesive compositions for the curable adhesive films are described in U.S. Patent Application Publication No. 2021 / 0102099 (Unverhau et al.).

[0085] Various combinations of film-forming polymers or oligomers can be used in the curable adhesive free-standing films of the present disclosure.

[0086] Unsaturated free radical polymerizable groups The curable adhesive free-standing film comprises a species that comprises unsaturated free-radically polymerizable groups, which can be a film-forming polymer or oligomer (i.e., a reactive polymer or oligomer that comprises unsaturated free-radically polymerizable groups) or a species other than a film-forming polymer or oligomer.

[0087] In some embodiments, the unsaturated free radically polymerizable groups are selected from ethylenically unsaturated groups, including vinyl-containing groups, such as (meth)acrylate groups.

[0088] In some embodiments, the unsaturated free radically polymerizable group is part of a crosslinker (i.e., a crosslinkable species) that is different from the film-forming polymer or oligomer. Such crosslinkers contain two or more, preferably three or more, unsaturated free radically polymerizable groups, including vinyl-containing groups such as (meth)acrylate groups. In some embodiments, the crosslinker is a crosslinking monomer. In some embodiments, the crosslinker is an oligomer.

[0089] Exemplary crosslinking agents include trimethylolpropane triacrylate (TMPTA), ethoxy trimethylolpropane triacrylate, propoxy glycerol triacrylate, pentaerythritol triacrylate, bis trimethylolpropane tetraacrylate, pentaerythritol tetraacrylate, ethoxy pentaerythritol tetraacrylate, trimethylolpropane trimethacrylate, ethoxy pentaerythritol triacrylate, ditrimethylolpropane tetraacrylate, or combinations thereof. Other exemplary crosslinking agents include multifunctional polyol derivatives. For example, acrylic or methacrylic acid esters of selected polyols, at least two of which are esterified, can be used as crosslinking agents. Exemplary such crosslinkers are ethylene glycol diacrylate, diethylene glycol diacrylate, glycerol diacrylate, glycerol triacrylate, ethylene dimethacrylate, 1,3-propanediol dimethacrylate, 1,2,4-butanetriol trimethacrylate, pentaerythritol tri- and tetraacrylate and methacrylate, trimethylolpropane triacrylate, hexanediol diacrylate, tetraethylene glycol diacrylate, neopentyl glycol diacrylate, and the like.

[0090] Transition metal cations The curable adhesive film further comprises a transition metal cation. Examples of suitable transition metal cations include molybdenum, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, or zinc. In some embodiments, the transition metal cation is a copper cation, such as Cu(II), as can be found in copper(II) acetate monohydrate and copper(II) naphthenate. In some embodiments, the transition metal cation is an iron cation, such as Fe(II) or Fe(III), as can be found in Black11 (Fe3O4 or FeO·Fe2O3), Red102 (Fe2O3), or Yellow42 (Fe2O3·H2O).

[0091] Useful transition metal complexes are described in WO 2018 / 215889 (Townsend et al.) and have the general formula: [ML p ] n+ A - where M represents a transition metal capable of participating in redox cycles with oxidants and reductants. Useful transition metals M include catalytically active valence states of Cu, Fe, Ru, Cr, Mo, Pd, Ni, Pt, Mn, Rh, Re, Co, V, Au, Nb, and Ag. Preferred low valence transition metals include Cu(II), Fe(II), Ru(II), and Co(II). Other valence states of these metals may be used, and active low valence states may be generated in situ.

[0092] Expression [ML p ] n+ A -In such exemplary complexes of, L represents a ligand. The ligand L can be used to solubilize the transition metal salt in a suitable solvent and adjust the redox potential of the transition metal for appropriate reactivity and selectivity. The ligand can direct the transition metal complex to undergo a desired one-electron transfer process rather than a two-electron process such as oxidative addition / reductive elimination. The ligand may further enhance the stability of the complex in the presence of different monomers and solvents or at different temperatures. Acidic monomers and monomers that strongly complex the transition metal can still be efficiently polymerized by appropriate selection of the ligand.

[0093] Useful ligands include ligands having one or more nitrogen, oxygen, phosphorus, and / or sulfur atoms that can be coordinated to the transition metal through a sigma bond, ligands containing two or more carbon atoms that can be coordinated to the transition metal through a pi bond, and the like.

[0094] Such ligands may be monodentate or polydentate compounds preferably containing up to about 10 carbon atoms and up to 10 heteroatoms selected from aluminum, boron, nitrogen, sulfur, non-peroxide oxygen, phosphorus, arsenic, selenium, antimony, and tellurium, where upon addition to the metal atom, after losing 0, 1, or 2 hydrogens, the polydentate compounds preferably form a metal M n+ Together with the aryl group, they form a 4-, 5-, or 6-membered saturated or unsaturated ring. Examples of suitable monodentate ligands are carbon monoxide; alcohols such as ethanol, butanol, and phenol; pyridine, nitrosonium (i.e., NO + ); compounds of Group 15 elements such as ammonia, phosphine, trimethylamine, trimethylphosphine, tributylphosphine, triphenylamine, triphenylphosphine, triphenylarsine, or tributylphosphite; nitriles such as acetonitrile or benzonitrile; isonitriles such as phenylisonitrile or butylisonitrile; carbene groups such as ethoxymethylcarbene or dithiomethoxycarbene; alkylides such as methylidene or ethylidene.

[0095] Exemplary suitable polydentate compounds or groups include dipyridyl; 1,2-bis(diphenyl-phosphino)ethane; 1,2-bis(diphenylarsino)ethane; bis(diphenylphosphino)methane; polyamines such as ethylenediamine, propylenediamine, tetramethylethylenediamine, hexamethyltris-aminoethylamine, diethylenetriamine, 1,3-diisocyanopropane, and hydridotripyrazolylborate; hydroxycarboxylic acids such as glycolic acid, lactic acid, and salicylic acid; polyhydric phenols such as catechol and 2,2'-dihydroxybiphenyl; hydroxyamines such as ethanolamine, propanolamine, and 2-aminophenol; diethyldithiocarbamate, dibenzylamine, and the like. dithiocarbamates such as dildithiocarbamate; xanthates such as ethyl xanthate, phenyl xanthate; dithiolenes such as bis(perfluoromethyl)-1,2-dithiolenes; aminocarboxylic acids such as alanine, glycine and o-aminobenzoic acid; diamine dicarboxylic acids such as oxalamide, biuret; diketones such as 2,4-pentanedione; hydroxyketones such as 2-hydroxyacetophenone; α-hydroxyoximes such as salicylaldoxime; ketoximes such as benzyloxime; 1,10-phenanthroline, porphyrins; crown ethers such as cryptands and 18-crown-6 ether, and glyoximes such as dimethylglyoxime.

[0096] Other suitable ligands that can coordinate to transition metals via sigma bonds include, for example, F - , O.H. - , Cl - , Br - , I - , and hydrides, as well as inorganic groups such as, for example, CN - , SCN -The ligands are organic groups such as aryloxy, acetoxy, formyloxy, and benzoyloxy. The ligands can also be units of polymers, for example, amino groups in poly(ethyleneimine), phosphino groups in poly(4-vinylphenyldiphenylphosphine), carboxylic acid groups in poly(acrylic acid), and isonitrile groups in poly(4-vinylphenylisonitrile).

[0097] Useful ligands containing two or more carbon atoms capable of coordinating to a transition metal through a pi bond are provided by any monomeric or polymeric compound having available unsaturated groups, such as ethylenic, acetylenic, or aromatic groups that have available pi electrons regardless of the total molecular weight of the compound.

[0098] Exemplary pi-bonded ligands include linear and cyclic ethylenic and acetylenic compounds having less than 100 carbon atoms (if monomeric), preferably less than 60 carbon atoms, and 0-10 heteroatoms selected from nitrogen, sulfur, non-peroxide oxygen, phosphorus, arsenic, selenium, boron, aluminum, antimony, tellurium, silicon, germanium, and tin, the ligands being ethylene, acetylene, propylene, methylacetylene, α-butene, 2-butene, diacetylene, butadiene, 1,2-dimethylacetylene, cyclobutene, pentene, cyclopentene, hexene, cyclohexene, 1,3-cyclohexadiene, cyclopentadiene, 1,4-cyclohexadiene, cycloheptene, 1-octene, 4-octene, 3,4-dimethyl-3-hexene, and 1-decene; 3 -Allyl, η 3 -Pentenyl, norbornadiene, η 5 -cyclohexadienyl, cycloheptatriene, cyclooctatetraene, and substituted and unsubstituted carbocyclic and heterocyclic aromatic ligands having up to 25 rings and up to 100 carbon atoms and up to 10 heteroatoms selected from nitrogen, sulfur, non-peroxide oxygen, phosphorus, arsenic, selenium, boron, aluminum, antimony, tellurium, silicon, germanium, and tin, such as, for example, η 5-Cyclopentadienyl, benzene, mesitylene, toluene, xylene, tetramethylbenzene, hexamethylbenzene, fluorene, naphthalene, anthracene, chrysene, pyrene, η 7 -Cycloheptatrienyl, triphenylmethane, paracyclophane, 1,4-diphenylbutane, η 5 - Piroro, eta 5 -Thiophene, η 5 -Furan, pyridine, γ-picoline, quinaldine, benzopyran, thiochrome, benzoxazine, indole, acridine, carbazole, triphenylene, silabenzene, arsabenzene, stibabenzene, 2,4,6-triphenylphosphabenzene, η 5 -Selenophene, dibenzostampin, eta 5 -Tellurophene, phenothiazine, selenanthrene, phenoxaphosphine, phenarsazine, phenatellazine, η 5 -Methylcyclopentadienyl, η 5 -pentamethylcyclopentadienyl, and 1-phenylborabenzene. Other suitable aromatic compounds can be found by reference to any of the many chemical handbooks.

[0099] Preferred ligands include unsubstituted and substituted pyridines and bipyridines, N,N,N',N'-tetramethylethylenediamine and tris(N,N-dimethylamino-ethyl)amine, acetonitrile, tertiary amines including phosphites (e.g., (CHO)P), 1,10-phenanthroline, porphyrins, cryptands and polydentate amines such as crown ethers (e.g., 18-crown-6 ether). Most preferred ligands are polydentate amines, bipyridines, and phosphites. Ligands and ligand-metal complexes useful in the initiator system of the present disclosure are described in Matyjaszewski and Xia, Chemical Reviews, 2001, vol. 101, pp. 2921-2990.

[0100] Expression [ML p ] n+ A -In such an exemplary complex of - represents an anion. Exemplary useful anions A - Examples of the cation ion include halide ions (e.g., chloride ion, bromide ion, fluoride ion), alkoxy groups having 1 to 6 carbon atoms (i.e., C1 to C6 alkoxy), nitrate ion, sulfate ion, phosphate ion, diphosphate ion, hexafluorophosphate ion, triflate, methanesulfonate ion, arenesulfonate ion, cyanide ion, alkanecarboxylate ions (e.g., acetate ion), and arenecarboxylate ions (e.g., benzenecarboxylate ion).

[0101] Expression [ML p ] n+ A - In such exemplary complexes, n is a formal charge on the transition metal having an integer value from 1 to 7, preferably from 1 to 3, and p is the number of ligands on the transition metal having a value from 1 to 9, preferably from 1 to 2.

[0102] Redox accelerator In some embodiments, the curable adhesive free-standing film further comprises a redox accelerator, such as a quaternary amine. In other embodiments, the redox accelerator may be selected from organic or inorganic chloride ion-containing compounds, such as amine hydrochlorides or sodium chloride.

[0103] For example, the quaternary ammonium salt dimethyl benzyl aniline chloride (DMBAC) is an active component of a redox couple for radical initiation of acrylic or vinyl polymerization in solvents.

[0104] Exemplary quaternary ammonium salts have the formula: [ka] (In the formula, R 7 , R 8 , R 9 , and R 11may be the same or different and are hydrocarbyl, hydrocarbylaryl, aryl, or substituted derivatives thereof, and X is Cl, Br, or F, or a soft anion such as SbF, BF, or PF.

[0105] Phosphonium salts may also be useful as redox promoters. Exemplary phosphonium salts have the formula: [ka] (In the formula, R 12 , R 13 , R 14 , and R 15 may be the same or different and are hydrocarbyl, hydrocarbylaryl, aryl, or substituted derivatives thereof, and X is Cl, Br, I, or F, or a soft anion such as SbF, BF, or PF.

[0106] Preferably, R 12 , R 13 , and R 14 are each phenyl or C1-C5 alkyl.

[0107] Desirably, the phosphonium salt used is selected from allyltriphenylphosphonium bromide (ATPB), 2-(ethoxycarbonyl)ethyl-triphenylphosphonium bromide, 1-ethoxycarbonylethyltriphenylphosphonium bromide, 4-ethoxycarbonylbutyltriphenylphosphonium bromide, carbethoxymethyltriphenylphosphonium bromide, or methyltriphenylphosphonium bromide.

[0108] Various combinations of redox promoters may be used if desired.

[0109] In certain embodiments, the redox accelerator is used in an amount of at least 0.25 weight percent, and typically up to 4 weight percent, based on the weight of the curable adhesive free-standing film (e.g., the combination of the film-forming polymer, the transition metal compound, the crosslinker, and the redox accelerator).

[0110] The redox accelerator and the transition metal cation are involved in a redox reaction initiated by an oxidizing agent in the activator that results in crosslinking of the crosslinkable species. For example, the oxidizing agent (e.g., tert-butylperoxy-2-ethylhexyl carbonate (TBEC)) is believed to oxidize the transition metal cation (e.g., Cu(I) to Cu(II)) to form a radical (e.g., tert-butoxy radical), which initiates (typically catalytically) crosslinking of the crosslinkable species, thereby forming a crosslinked network. Without wishing to be bound by theory, in this example, the redox accelerator is believed to function as a reducing agent for the initially provided Cu(II) cation to Cu(I).

[0111] Curable foam support layer In certain embodiments, the curable foam support layer comprises a base polymer or oligomer that may be the same as or different from the film-forming polymer or oligomer of the curable adhesive free-standing film. In certain embodiments, the curable foam support layer comprises a base polymer or oligomer that is the same as the film-forming polymer or oligomer of the curable adhesive free-standing film.

[0112] In certain embodiments, the curable foam support layer includes a crosslinking agent mixed therein. In certain embodiments, the system includes a crosslinking agent that is transferable (from the curable adhesive free-standing film) to the curable foam support layer. Exemplary crosslinking agents are those described herein with respect to the curable adhesive free-standing film.

[0113] In certain embodiments, the curable foam support layer further comprises a polymeric modulus modifier to provide a desired modulus. In certain embodiments, the polymeric modulus modifier comprises a polymer having a Tg of 100° C. or less, 90° C. or less, 80° C. or less, 70° C. or less, 60° C. or less, 50° C. or less, or 40° C. or less. In certain embodiments, the polymeric modulus modifier comprises a polyvinyl acetal resin, in particular polyvinyl butyral (PVB). In certain embodiments, the polymeric modulus modifier comprises a high acid polymer.

[0114] In some embodiments, the curable foam support layer comprises a transition metal cation as described for the curable adhesive free-standing film. In some embodiments, the curable foam support layer also comprises a redox accelerator as described for the curable adhesive free-standing film.

[0115] Base polymer or oligomer The curable foam support layer may be a closed cell, open cell, syntactic, or non-syntactic foam. Foams may be made using chemical blowing agents, physical blowing agents, mechanical mechanisms, etc., as known in the art.

[0116] In some embodiments, the base polymer or oligomer includes a film-forming polymer or oligomer, such as aromatic or aliphatic polyurethanes (including polymers made with aliphatic or aromatic diols, polyamides, saturated and unsaturated polyesters (e.g., polybutylene terephthalate, polyethylene terephthalate, polyglycolic acid, polylactic acid, poly-2-hydroxybutyrate, polycaprolactone, and combinations containing maleic acid repeat units); polyethers (e.g., polyacetals and their copolymers, polyphenylene oxides, polyetherketones, polyetheretherketones); natural and synthetic rubbers (e.g., polyisoprene, polychloroprene, nitrile rubber, butadiene-based rubber); alkyds; phenolic resins (e.g., novolacs and resols); amino resins (e.g., urea-formaldehyde resins, melamine-formaldehyde resins, and melamine-urea copolymer resins); epoxies (e.g., those made from adducts using bisphenol A, or telechelic amino resins capped with oxirane functional groups), and the like. In some embodiments, the film-forming polymer or oligomer is a (meth)acrylate-functional polymer, such as those made by adding (meth)acrylate end groups to a polyester, polyurethane, polybutadiene, or polyether polymer.

[0117] In some embodiments, the base polymer or oligomer of the curable foam support layer is a poly(meth)acrylate polymer or oligomer. In certain embodiments, the base polymer of the curable foam support layer is a silicone polymer. Acrylate and silicone foams are useful for their UV light stability, conformability, and ability to distribute stress. The acrylate polymer can be, for example, an acrylic acid ester of a non-tertiary alcohol having 1 to 18 carbon atoms. In some embodiments, the acrylic acid ester comprises a carbon-carbon chain having 4 to 12 carbon atoms, terminated with a hydroxyl oxygen atom, the chain containing at least half of the total number of carbon atoms in the molecule.

[0118] Particular useful acrylic acid esters can be polymerized into tacky, stretchable, and elastic adhesives.Examples of acrylic acid esters of non-tertiary alcohols include, but are not limited to, 2-methylbutyl acrylate, isooctyl acrylate, lauryl acrylate, 4-methyl-2-pentyl acrylate, isoamyl acrylate, sec-butyl acrylate, n-butyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, n-decyl acrylate, isodecyl acrylate, isodecyl methacrylate, and isononyl acrylate.Suitable acrylic acid esters of non-tertiary alcohols include, for example, 2-ethylhexyl acrylate and isooctyl acrylate.

[0119] To improve the strength of the foam, the acrylic acid ester may be copolymerized with one or more monoethylenically unsaturated monomers having a highly polar group. Such monoethylenically unsaturated monomers include, for example, acrylic acid, methacrylic acid, itaconic acid, acrylamide, methacrylamide, N-substituted acrylamide (e.g., N,N-dimethylacrylamide), acrylonitrile, methacrylonitrile, hydroxyalkyl acrylate, cyanoethyl acrylate, N-vinylpyrrolidone, N-vinylcaprolactam, and maleic anhydride. In some embodiments, these copolymerizable monomers are used in an amount of less than 20% by weight of the base polymer matrix.

[0120] Particularly useful are acrylate copolymers containing at least 6% by weight acrylic acid, and in other embodiments at least 8% by weight, or at least 10% by weight acrylic acid, each based on the total weight of the monomers in the acrylate copolymer. The adhesive may also contain small amounts of other useful copolymerizable monoethylenically unsaturated monomers, such as alkyl vinyl ethers, vinylidene chloride, styrene, and vinyl toluene.

[0121] In certain embodiments, the base polymer or oligomer of the curable foam support layer comprises a first (meth)acrylate copolymer comprising from 0.1 weight percent to 12 weight percent of (meth)acrylic acid monomer units, based on the weight of the first (meth)acrylate copolymer described herein with respect to the pressure sensitive adhesive of the curable self-supporting adhesive film. That is, in such embodiments, the base polymer or oligomer of the curable foam support layer may contain, as major monomer units, methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl acrylate, isobutyl acrylate, tert-butyl (meth)acrylate, n-pentyl (meth)acrylate, iso-pentyl (meth)acrylate, n-hexyl (meth)acrylate, iso-hexyl (meth)acrylate, cyclohexyl (meth)acrylate, phenyl (meth)acrylate, octyl (meth)acrylate, iso-octyl (meth)acrylate, 2-octyl (meth)acrylate, The (meth)acrylate copolymer comprises a linear or branched alkyl (meth)acrylate ester monomer unit selected from the group consisting of 2-ethylhexyl (meth)acrylate, decyl (meth)acrylate, undecyl (meth)acrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, heptadecyl (meth)acrylate, 2-propylheptyl (meth)acrylate, stearyl (meth)acrylate, isobornyl (meth)acrylate, benzyl (meth)acrylate, nonyl (meth)acrylate, isofloryl (meth)acrylate, and any combination or mixture thereof. In certain embodiments, the (meth)acrylate copolymer has a Tg of 0° C. or less. In certain embodiments, the (meth)acrylate copolymer has a Tg of -70°C to 0°C, -70°C to -10°C, -60°C to -10°C, -60°C to -20°C, -60°C to -30°C, -55°C to -35°C, or -50°C to -40°C.

[0122] In some embodiments, the base polymer or oligomer of the curable foam support layer is made from a silicone polymer. Suitable silicone polymers can include, for example, MQ resins containing a resinous core and non-resinous polyorganosiloxane groups terminated with silicon-bonded hydroxyl groups, treated MQ resins, and polydiorganosiloxanes terminated with condensation reactive groups.

[0123] Such compositions can be used in structural glazing applications, as described in US Pat. No. 8,298,367 (Beger et al.).

[0124] Improved cohesive strength of the curable foam support layer can also be achieved by using a crosslinking agent such as 1,6-hexanediol diacrylate with a photoactive triazine crosslinking agent as taught in U.S. Patents 4,330,590 (Vesley) and 4,329,384 (Vesley et al.), or with a heat-activated crosslinking agent such as a lower alkoxylated aminoformaldehyde condensate having a C14 alkyl group, for example hexamethoxymethylmelamine or tetramethoxymethylurea or tetrabutoxymethylurea. Crosslinking may also be achieved by irradiating the composition with electron beam (i.e., "e-beam") radiation, gamma radiation, or X-rays. This crosslinking occurs in the preparation of the curable foam support layer and occurs prior to contact with the activator.

[0125] The base polymer or oligomer used in the foam can be prepared by any suitable polymerization method. Suitable polymerization methods include, but are not limited to, photopolymerization, thermal polymerization, or ionizing radiation polymerization. These methods can be carried out in solution, in emulsion, or in bulk without solvent. Bulk polymerization methods are described in U.S. Pat. No. 5,804,610 (Hamer et al.). Optionally, the photopolymerizable monomer may be partially polymerized to a viscosity of 1000-40,000 cps to facilitate coating. Alternatively, partial polymerization may be brought about by heat. If desired, the viscosity can also be adjusted by mixing the monomer with a thixotropic agent such as fumed silica.

[0126] Photopolymerization can be carried out in an inert atmosphere, such as under a blanket of nitrogen or argon gas. Alternatively, the inert environment can be achieved by temporarily covering the photopolymerizable coating with a plastic film transparent to ultraviolet light and irradiating the coating through the film. If the polymerizable coating is not covered during photopolymerization, the tolerable oxygen content of the inert atmosphere can be increased by incorporating an oxidizable tin compound, such as those disclosed in U.S. Patent No. 4,303,485 (Levens), into the photopolymerizable composition, allowing relatively thick coatings to be polymerized in air.

[0127] Crosslinking Agent In certain embodiments, the curable foam support layer includes a crosslinking agent mixed therein. In certain embodiments, the system includes a crosslinking agent that is transferable (from the curable adhesive free-standing film) to the curable foam support layer. Exemplary crosslinking agents are those described herein with respect to the curable adhesive free-standing film.

[0128] In certain embodiments, the crosslinker is the same as or different from the species containing unsaturated free radically polymerizable groups of the curable adhesive freestanding film. In certain embodiments, the crosslinker is the same as the species containing unsaturated free radically polymerizable groups of the curable adhesive freestanding film. In certain embodiments, the crosslinker is the species containing unsaturated free radically polymerizable groups of the curable adhesive freestanding film. That is, in certain embodiments, the crosslinker is the species containing unsaturated free radically polymerizable groups of the curable adhesive freestanding film that is transferred to the curable support layer.

[0129] The crosslinking agent (i.e., crosslinkable species) contained within the curable foam support layer and / or migrated into the curable foam support layer and contained within the curable adhesive free-standing film is activated when contact between the curable adhesive film and the activating surface initiates an oxidation-reduction cycle, thereby initiating crosslinking. This crosslinking of the crosslinking agent results in the curing of both the curable adhesive film and the curable foam support layer. It is believed that an interpenetrating crosslinked network is formed in the bulk of the adhesive layer, with a first network formed from the crosslinking agent and a second network formed from the film-forming polymer or oligomer. This crosslinked network is formed across the boundaries between the various layers of the cured tape (e.g., across the boundaries between the cured adhesive free-standing film and the cured foam support layer), as evidenced by cohesive failure of the cured tape.

[0130] FIG. 6 shows that Examples 1, 2, and 4 in the following examples have significant migration of crosslinker from the curable adhesive free-standing film to the curable foam support layer. Example 3 was prepared first with crosslinker in both the curable foam support layer and the curable adhesive free-standing film. Comparative Example 1 shows no substantial migration of crosslinker in FIG. 6, with no curable component present in the tape support layer. As shown in Table 3, the dynamic shear adhesion is much higher for Examples 1-4 than for Comparative Example 1.

[0131] Polymer Modulus Modifier In certain embodiments, the curable foam support layer further comprises a polymeric modulus modifier to provide a desired modulus, hi certain embodiments, the polymeric modulus modifier comprises a polymer having a Tg of 100° C. or less, 90° C. or less, 80° C. or less, 70° C. or less, 60° C. or less, 50° C. or less, or 40° C. or less.

[0132] In certain embodiments, the polymeric modulus modifier comprises a polyvinyl acetal resin, particularly polyvinyl butyral (PVB). In certain embodiments, the polymeric modulus modifier comprises a high acid polymer. It is believed that the polymeric modulus modifier does two things: it increases the foam's modulus and it strengthens the system against applied forces.

[0133] In certain embodiments, the polyvinyl acetal resin has the formula: [ka] (wherein R1 is hydrogen or an alkyl group having 1 to 7 carbon atoms (C1 to C7)).

[0134] As is known in the art, the polyvinyl acetal resin can be obtained, for example, by reacting polyvinyl alcohol with an aldehyde. The polyvinyl alcohol resin is not limited by the production method. For example, a resin produced by saponifying polyvinyl acetate or the like with an alkali, acid, aqueous ammonia, or the like can be used. The polyvinyl alcohol resin may be completely saponified or partially saponified. It is desirable to use a resin having a saponification degree of 80 mol% or more. The polyvinyl alcohol resin can be used alone or in combination of two or more.

[0135] Aldehydes used in the production of polyvinyl acetal resins include formaldehyde (including paraformaldehyde), acetaldehyde (including para-acetaldehyde), propionaldehyde, butyraldehyde, n-octylaldehyde, amylaldehyde, hexylaldehyde, heptylaldehyde, 2-ethylhexylaldehyde, cyclohexylaldehyde, furfural, glyoxal, glutaraldehyde, benzaldehyde, 2-methylbenzaldehyde, 3-methylbenzaldehyde, 4-methylbenzaldehyde, p-hydroxybenzaldehyde, m-hydroxybenzaldehyde, phenylacetaldehyde, beta-phenylpropionaldehyde, etc. These aldehydes can be used alone or in combination of two or more.

[0136] In some embodiments, the alkyl residue of the aldehyde contains 1 to 7 carbon atoms. In other embodiments, the alkyl residue of the aldehyde contains 3 to 7 carbon atoms, such as in butyraldehyde, hexylaldehyde, and n-octylaldehyde. Of these, butyraldehyde, also known as butanal, is the most commonly utilized. Polyvinyl butyral ("PVB") resins are commercially available from Kuraray under the trade name MOWITAL and from Solutia under the trade name BUTVAR.

[0137] In some embodiments, the polyvinyl acetal (e.g. butyral) resin has a Tg in the range of 60°C to 80°C or 60°C to 75°C. In some embodiments, the Tg of the polyvinyl acetal (e.g. butyral) resin is at least 65°C or at least 70°C. If other aldehydes such as n-octyl aldehyde are used in the preparation of the polyvinyl acetal resin, the Tg may be less than 65°C, or even less than 60°C. The Tg of the polyvinyl acetal resin is typically at least 35°C, at least 40°C, or at least 45°C. If the polyvinyl acetal resin has a Tg less than 60°C, a higher concentration of high Tg monomers can be used compared to those utilizing polyvinyl butyral resins. If other aldehydes such as acetaldehyde are used in the preparation of the polyvinyl acetal resin, the Tg may be greater than 75°C, or greater than 80°C. When the polyvinyl acetal resin has a Tg greater than 70° C., a higher concentration of low Tg monomer can be used compared to those utilizing polyvinyl acetal butyral resins.

[0138] Polyvinyl acetal (e.g., PVB) resins typically have a weight average molecular weight (Mw) of at least 10,000 g / mole, 15,000 g / mole, or 30,000, and no greater than 100,000 g / mole, 80,000 g / mole, or 60,000 g / mole.

[0139] Polyacetal resins are typically random copolymers, although block copolymers and tapered block copolymers may provide similar benefits as random copolymers. Exemplary polyvinyl acetal resins are described in U.S. Patent Application Publication No. 2021 / 0102100 (Xia et al.).

[0140] In certain embodiments, if used, the polyvinyl acetal resin is used in an amount of at least 5 weight percent, at least 7 weight percent, or at least 10 weight percent, based on the total weight of the curable foam support layer composition, If used, the polyvinyl acetal resin is used in an amount of up to 25 weight percent, up to 20 weight percent, or up to 15 weight percent, based on the total weight of the curable foam support layer composition.

[0141] In certain embodiments, the polymeric modulus modifier comprises a high acid polymer. High acid in this context means that there is an acrylate polymer with a higher amount of acrylic acid than in conventional pressure sensitive adhesives, which are typically 90:10 isooctyl acrylate:acrylic acid. This makes the polymer "stiffer" (i.e., has a higher modulus).

[0142] In certain embodiments, the high acid polymer is a second (meth)acrylate copolymer that includes 15 weight percent to 40 weight percent of (meth)acrylic acid monomer units, based on the weight of the second (meth)acrylate copolymer described herein with respect to the pressure sensitive adhesive of the curable self-supporting adhesive film. That is, in such embodiments, the high acid polymer (i.e., the second (meth)acrylate copolymer described herein) comprises, as major monomer units, methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl acrylate, isobutyl acrylate, tert-butyl (meth)acrylate, n-pentyl (meth)acrylate, iso-pentyl (meth)acrylate, n-hexyl (meth)acrylate, iso-hexyl (meth)acrylate, cyclohexyl (meth)acrylate, phenyl (meth)acrylate, octyl (meth)acrylate, iso-octyl (meth)acrylate, 2-octyl (meth)acrylate, 2-methyl-3-phenylpropanediol ... )acrylate, 2-ethylhexyl (meth)acrylate, decyl (meth)acrylate, undecyl (meth)acrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, heptadecyl (meth)acrylate, 2-propylheptyl (meth)acrylate, stearyl (meth)acrylate, isobornyl (meth)acrylate, benzyl (meth)acrylate, nonyl (meth)acrylate, isophoryl (meth)acrylate, and any combination or mixture thereof. In certain embodiments, the high acid polymer has a Tg of 100° C. or less, 80° C. or less, 60° C. or less, 50° C. or less, 45° C. or less, or even 40° C. or less. In certain embodiments, the high acid polymer has a Tg of 2°C to 100°C, 2°C to 80°C, 2°C to 60°C, 2°C to 50°C, 2°C to 45°C, 5°C to 45°C, 5°C to 40°C, 5°C to 35°C, or 10°C to 30°C.

[0143] The high acid polymers are believed to provide outstanding mechanical properties, particularly due to the relatively high concentration of (meth)acrylic acid monomer units.

[0144] In certain embodiments, if used, the high acid polymer is used in an amount of at least 1 weight percent, at least 2 weight percent, at least 3 weight percent, or at least 4 weight percent, based on the total weight of the curable foam support layer, If used, the high acid polymer is used in an amount of up to 35 weight percent, up to 30 weight percent, up to 25 weight percent, up to 20 weight percent, or up to 15 weight percent, based on the total weight of the curable foam support layer.

[0145] Optional Additives Optionally, the curable foam support layer contains one or more additives, which may include, for example, fillers, antioxidants, viscosity modifiers, pigments (inorganic or organic), tackifying resins, fibers, flame retardants, antistatic and slip agents, thermally conductive particles, electrically conductive particles, continuous microfibers, filaments, and mixtures thereof.

[0146] Useful fillers include, for example, glass beads, metal oxide particles, silica particles (e.g., fumed silica), ceramic microspheres, hollow polymeric microspheres (such as those available under the trade name EXPANCEL 551DE from Akzo Nobel, Duluth, GA), hollow glass microspheres (such as those available under the trade name K37 from 3M Co., St Paul, MN), carbonates, metal oxides, silicates (e.g., talc, asbestos, clay, mica), sulfates (e.g., barium sulfate), metals in powder form (e.g., aluminum, zinc, and iron), silicon dioxide, and aluminum trihydrate. In certain embodiments, the filler comprises a solid or hollow particle. In certain embodiments, the solid or hollow particle comprises a polymer, glass, ceramic, or metal oxide material. If desired, a combination of two or more fillers may be used.

[0147] Examples of useful organic pigments include halogenated copper phthalocyanines, aniline black, anthraquinone black, benzimidazolone, azo condensates, arylamides, diarylides, disazo condensates, isoindolinones, isoindolines, quinophthalones, anthrapyrimidines, flavanthrones, pyrazolone oranges, perinone oranges, beta-naphthols, BON arylamides, quinacridones, perylenes, anthraquinones, dibromoanthrones, pyranthrones, diketopyrrolo-pyrrole pigments (DPP), dioxazine violet, copper and copper-free phthalocyanines, indanthrones, and the like.

[0148] Examples of useful inorganic pigments include titanium dioxide, zinc oxide, zinc sulfide, lithopone, antimony oxide, barium sulfate, carbon black, graphite, black iron oxide, black micaceous iron oxide, brown iron oxide, metal complex brown, lead chromate, cadmium yellow, yellow iron oxide, bismuth vanadate, lead chromate, lead molybdate, cadmium red, red iron oxide, Prussian blue, ultramarine, cobalt blue, chrome green (Brunswick green), chromium oxide, hydrated chromium oxide, organometallic complex, and lake dye pigments.

[0149] In certain embodiments, the curable foam support layer comprises a filler. In certain embodiments, the filler comprises fumed silica. In certain embodiments, the filler comprises solid or hollow particles. In certain embodiments, the solid or hollow particles comprise a polymer, a glass, a ceramic, or a metal oxide material.

[0150] The various additives may be used in amounts typical for adhesive tapes.

[0151] Preparation of the Curable Foam Support Layer The polymers used to make the curable foam support layer can be made using conventional techniques, such as solution coating onto a web. In a preferred embodiment, the polymers of the curable foam support layer are hot melt processable and made in a hot melt process. Hot melt processing, such as hot melt blending or hot melt extrusion, can be accomplished by any suitable means, including those disclosed in U.S. Patent Application Publication No. 2013 / 0184394(A1) (Satrijo et al.).

[0152] The polymers used to make the curable foam support layer may be initially coated onto and polymerized against a flexible backing sheet (e.g., a release liner) that has a low adhesion surface from which the polymerized layer is easily removable and is in most cases self-sustaining. If the opposite surface of the backing sheet also has a low adhesion surface, the backing sheet together with its polymerized layer can be wound up in roll form and stored prior to assembling the finished adhesive article.

[0153] In some embodiments, the curable foam support layer may be an open cell foam, a closed cell foam, or a combination thereof. It may be a syntactic foam or a non-syntactic foam.

[0154] In certain embodiments, the curable foam support layer is a foam made using a blowing agent. In certain embodiments, the curable foam support layer includes a blowing agent and a base polymer or oligomer. In certain embodiments, the curable foam support layer includes a blowing agent and the same ingredients as the curable adhesive free-standing film.

[0155] In certain embodiments, the blowing agent comprises expandable microspheres, hollow glass bubbles, nitrogen bubbles, and optionally surfactant-stabilized bubbles formed from physical agitation and stabilized with a surfactant, preferably a silicone, or fluorochemical known to be useful for foaming organic liquids having low surface tension, such as fluorosurfactants available under the trade name FC-4430 from 3M Company, St. Paul, Minn., and those described in U.S. Pat. No. 4,415,615 (Esmay et al.).

[0156] In some embodiments, the foam is a syntactic foam containing hollow microspheres, e.g., hollow glass microspheres. Useful hollow glass microspheres include those having a density of less than 0.4 grams per milliliter (g / mL) and a diameter of 5 to 200 micrometers. The microspheres may be clear, coated, dyed, or combinations thereof. The microspheres typically comprise 5 to 65 volume percent of the foam composition. Examples of useful acrylic foams made in this manner are disclosed in U.S. Pat. Nos. 4,415,615 (Esmay et al.) and 6,103,152 (Gehlsen et al.).

[0157] In some embodiments, foams may be formed by blending expanded polymeric microspheres into a polymerizable composition. In some embodiments, foams may be formed by blending expandable polymeric microspheres into a composition and expanding the microspheres. Expandable polymeric microspheres include a polymer shell and a core material in the form of a gas, liquid, or combinations thereof. Upon heating to a temperature at or below the melting or flow temperature of the polymer shell, the polymer shell expands to form the microspheres. Suitable core materials include propane, butane, pentane, isobutane, neopentane, isopentane, and combinations thereof. The thermoplastic resin used for the polymeric microsphere shell can affect the mechanical properties of the foam, and the foam properties can be adjusted by the selection of the microspheres or by using a mixture of different types of microspheres. Examples of commercially available expandable microspheres include those available under the trade name EXPANCEL from Akzo Nobel Pulp and Performance Chemicals AB, Sundsvall, Sweden. Methods for making foams containing expandable polymeric microspheres and details of these microspheres are described in US Pat. No. 6,103,152 (Gehlsen et al.).

[0158] Foams may also be prepared by forming gas voids in the composition using various mechanisms, including, for example, mechanical mechanisms, chemical mechanisms, and combinations thereof. Useful mechanical foaming mechanisms include, for example, agitating the composition (e.g., shaking, stirring, or whipping the composition, and combinations thereof), injecting gas into the composition (e.g., inserting a nozzle under the surface of the composition and blowing gas into the composition), and combinations thereof. A method for making foams containing voids formed by a blowing agent is described in U.S. Patent No. 6,586,483 (Kolb et al.).

[0159] In an exemplary embodiment, the curable support foam layer has a hardness of 320 kilograms per cubic meter (kg / m 3 )~1041kg / m 3, 400kg / m 3 ~880kg / m 3 , or 561 kg / m 3 ~800kg / m 3 The foam has a density of 0.01g / g.

[0160] Optional Barrier Film Support Layer Suitable materials for the barrier film support layer include, for example, metals, polyolefins such as high-density polyethylene (HDPE), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), ultra linear low-density polyethylene (U-LLDPE) and polypropylene (PP); polyvinyl polymers such as polyvinyl chloride (PVC) and polyvinyl acetate (PVA); polyolefin-based copolymers such as ethylene-methacrylic acid copolymer (EEMA) and ethylene-vinyl acetate copolymer (EVA); polyurethanes; natural or synthetic rubbers; block copolymers such as acrylic block copolymers and styrene-isoprene-vinyl acetate copolymers; polyamide-modified polyethers, and thermoplastic elastomers (TPE); acrylate resins such as polymethyl methacrylate (PMMA). methacrylate, PMMA; polyesters such as polyethylene terephthalate (PET); polycarbonate; norbornene-based resins; triacetyl cellulose (TAC); and metal foils such as aluminum foil. Such materials can be used alone or in combination.

[0161] The above materials may be composed of one of the aforementioned materials or a combination of two or more of them. For example, one or both of the barrier film support layers may be a composite film obtained by laminating and integrating two or more polymer films. Alternatively, one or both of the barrier film support layers may be a blend or copolymer of two or more of the aforementioned polymers.

[0162] Preferred materials for the barrier film support layer are thermoplastics that are semi-crystalline and have a melting temperature of at least 70° C., at least 75° C., at least 80° C., or at least 85° C. Preferred semi-crystalline thermoplastics have a melting temperature of at most 130° C., at most 125° C., at most 120° C., or at most 112° C.

[0163] The barrier film support layer may also contain fillers including reinforcing agents, core-shell particles, solid or hollow microspheres (polymeric, glass, ceramic, or metal oxide), fibers, electrically or thermally conductive materials, dyes, colorants, plasticizers, tackifiers, UV stabilizers, and the like.

[0164] Activator An activator designed to bond a curable adhesive free-standing film to a substrate is a liquid at ambient temperature and pressure. It contains a component that initiates the curing of the curable adhesive free-standing film. In some embodiments, the activator includes an oxidizing agent and a film-forming polymer or oligomer.

[0165] Oxidizing agent Any suitable oxidizing agent can be used. Suitable oxidizing agents include, for example, organic peroxides, inorganic peroxides, and persulfates. Suitable organic peroxides include, for example, hydroperoxides, di-peroxides, ketone peroxides, diacyl peroxides, dialkyl peroxides, peroxyketals, peroxyesters, and peroxydicarbonates.

[0166] Suitable organic peroxides include hydroperoxides containing the structural moiety ROOH, where R is straight chain alkyl (e.g., C1-C20 straight chain alkyl), branched chain alkyl (e.g., C3-C20 branched chain alkyl), cycloalkyl (e.g., C6-C12 cycloalkyl), alkaryl (e.g., C7-C20 alkaryl), aralkyl (e.g., C7-C20 aralkyl), and aryl (e.g., C6-C12 aryl). Exemplary organic hydroperoxides include t-butyl hydroperoxide, t-amyl hydroperoxide, p-diisopropylbenzene hydroperoxide, cumene hydroperoxide, pinane hydroperoxide, p-methane hydroperoxide, and 1,1,3,3-tetramethylbutyl hydroperoxide.

[0167] Suitable organic peroxides include those having the moiety R 1 -OOR 2 -OOR 3 and di-peroxides containing R 1 and R 3 is independently selected from H, straight chain alkyl (e.g., C1-C6 straight chain alkyl), branched chain alkyl (e.g., C1-C6 branched chain alkyl), cycloalkyl (e.g., C5-C10 cycloalkyl), alkaryl (e.g., C7-C12 alkaryl), aralkyl (e.g., C7-C20 aralkyl), or aryl (e.g., C6-C10 aryl); R 2 is selected from straight chain alkyl (eg, C1 to C6 straight chain alkyl) or branched chain alkyl (eg, C1 to C6 branched chain alkyl).

[0168] Suitable ketone peroxides include, for example, methyl ethyl ketone peroxide, methyl isobutyl ketone peroxide, methyl cyclohexanone peroxide, and cyclohexanone peroxide.Suitable peroxyesters include, for example, alpha-cumyl peroxyneodecanoate, t-butyl peroxypivalate, t-butyl peroxyneodecanoate, 2,2,4-trimethylpentyl peroxy-2-ethylhexanoate, t-amyl peroxy-2-ethylhexanoate, t-butyl peroxy-2-ethylhexanoate, di-t-butyl peroxyisophthalate, di-t-butyl peroxyhexahydroterephthalate, t-butyl peroxy-3,3,5-trimethylhexanoate, t-butyl peroxyacetate, t-butyl peroxybenzoate, and t-butyl peroxymaleate. Suitable peroxydicarbonates include, for example, di-3-methoxyperoxydicarbonate, di-2-ethylhexylperoxy-dicarbonate, bis(4-t-butylcyclohexyl)peroxydicarbonate, diisopropyl-1-peroxydicarbonate, di-n-propylperoxydicarbonate, di-2-ethoxyethyl-peroxydicarbonate, and diallylperoxydicarbonate.

[0169] Suitable diacyl peroxides include, for example, acetyl peroxide, benzoyl peroxide, decanoyl peroxide, 3,3,5-trimethylhexanoyl peroxide, 2,4-dichlorobenzoyl peroxide, and lauroyl peroxide.

[0170] Suitable dialkyl peroxides include, for example, di-t-butyl peroxide, dicumyl peroxide, t-butylcumyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, 1,3-bis(t-butylperoxyisopropyl)benzene, and 2,5-dimethyl-2,5-di(t-butylperoxy)-3-hexane.

[0171] Suitable peroxyketals include, for example, 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(t-butylperoxy)cyclohexane, 2,2-bis(t-butylperoxy)butane, 2,2-bis(t-butylperoxy)octane, and 4,4-bis(t-butylperoxy)valeric acid-n-butyl ester.

[0172] Other suitable organic peroxides may further include t-butyl peroxyethylhexyl carbonate, t-butyl peroxytrimethylhexanoate, t-butyl peroxyethylhexanoate, t-amyl peroxyethylhexanoate, t-octyl peroxyethylhexanoate, t-amyl peroxyethylhexyl carbonate, t-butyl peroxyisopropyl carbonate, t-butyl peroxyneodecanoate, and t-butyl peroxyisobutyrate.

[0173] In certain embodiments, the oxidizing agent is present in the activator in an amount of at least 0.5 weight percent, at least 1 weight percent, at least 2 weight percent, or at least 4 weight percent, based on the total weight of the activator composition. In certain embodiments, the oxidizing agent is present in the activator in an amount of up to 20 weight percent, up to 15 weight percent, up to 10 weight percent, or up to 5 weight percent, based on the total weight of the activator composition.

[0174] Film-forming polymer or oligomer In addition to an oxidizing agent, in some embodiments, the activating agent comprises a film-forming polymer or oligomer.

[0175] In some embodiments, the film-forming polymer or oligomer is as described herein with respect to the curable adhesive free-standing film. In some embodiments, the film-forming polymer or oligomer is a reactive polymer or oligomer that includes an unsaturated free-radically polymerizable group, as described herein with respect to the curable adhesive free-standing film. In some embodiments, the film-forming polymer or oligomer is different from the reactive species that includes an unsaturated free-radically polymerizable group, as described herein with respect to the curable adhesive free-standing film. Thus, in some embodiments, the activator may include a reactive species that includes an unsaturated free-radically polymerizable group, as described herein with respect to the curable adhesive free-standing film. These components may be the same or different from those components in the curable adhesive free-standing film.

[0176] In some embodiments, the film-forming polymer may include a rubber and / or a (meth)acrylic resin. In some embodiments, the (meth)acrylic resin is a (meth)acrylic polymer made from any of the monomers described above with respect to the curable adhesive free-standing film and the curable foam support layer. In some embodiments, the (meth)acrylic polymer is any of those described above with respect to the curable adhesive free-standing film and the curable foam support layer.

[0177] In some embodiments, the rubber comprises a block copolymer of styrene and an alkene. In some embodiments, the rubber comprises a styrene-ethylene / butylene-styrene block copolymer grafted with maleic anhydride. In some embodiments, the rubber comprises at least one of a styrene-isoprene-styrene copolymer, a styrene-butadiene-styrene copolymer, a styrene-ethylene-butylene-styrene copolymer.

[0178] In some embodiments, the (meth)acrylic resin is an amine-functional (meth)acrylic resin that is the polymerization reaction product of an amine-functional (meth)acryloyl compound (e.g., amine-functional (meth)acrylic acid esters and amides) with a non-amine vinyl monomer, as described in U.S. Pat. No. 10,640,656 (Moren et al.). In some embodiments, the amine-functional (meth)acrylic resin has a calculated glass transition temperature (Tg) of 12° C. or greater. In some embodiments, the amine-functional (meth)acrylic resin has a calculated Tg of 20° C. or greater. In some embodiments, the amine-functional (meth)acryloyl compounds (e.g., amine-functional (meth)acrylic acid esters and amides) include 2-(N,N-dimethylaminoethyl)(meth)acrylate, 2-(N,N-diethylaminoethyl)(meth)acrylate, 2-(t-butylaminoethyl)(meth)acrylate, 2-(N,N-dimethylaminoethyl)(meth)acrylamide, 2-(N,N-diethylaminoethyl)(meth)acrylamide, 2-(t-butylaminoethyl)(meth)acrylamide, and N-(meth)acryloylpiperidine. In some embodiments, the non-amine vinyl monomer is selected from the group consisting of (meth)acrylic acid, (meth)acrylic acid esters, (meth)acrylamides, vinyl esters, styrene, (meth)acrylonitrile, and mixtures thereof. In some embodiments, the non-amine vinyl monomer is a (meth)acrylic acid ester of a C1 to C18 alcohol.

[0179] Optional Additives In some embodiments, the activator also includes a component as described herein with respect to the curable adhesive free-standing film. For example, in some embodiments, the activator also includes a transition metal cation as described herein with respect to the curable adhesive free-standing film.

[0180] In some embodiments, the activator comprises a plasticizer. In some embodiments, the plasticizer has the following formula: (RX-) nZ, where each R can be hydrogen, C1-C14 alkyl, aryl, alkaryl, or aralkyl, each optionally interrupted by oxygen, nitrogen, carbonyl, carboxyl, or carbamide; each X can be oxygen, nitrogen, carbonyl, carboxyl, or carbamide; Z can be hydrogen, C1-C14 alkyl, aryl, alkaryl, aralkyl, C1-C14 alkylene, arylene, alkarylene, aralkylene, each optionally interrupted by oxygen, nitrogen, carbonyl, carboxyl, or carbamide; and n is an integer from 1 to 5. In some embodiments, n is an integer from 1 to 4.

[0181] In some embodiments, the plasticizer is selected from at least one of the following: benzoate, myristate, citrate, acetate, succinate, glutarate, adipate, sebacate, and combinations thereof. In some embodiments, the plasticizer is selected from at least one of the following: benzoate, myristate, citrate, and combinations thereof. The citrate may have 1, 2, 3, or 4 R groups.

[0182] The activator composition further comprises a liquid carrier. In some embodiments, the liquid carrier is a solvent. In some embodiments, the activator composition comprises from 75 weight percent to 99 weight percent, or from 93 weight percent to 98 weight percent of the solvent, all weight percentages being based on the total weight of the activator composition.

[0183] In some embodiments, the activator composition further comprises a silane (eg, an epoxy silane).

[0184] In some embodiments, the activator is free of tackifiers, free of species containing unsaturated free-radically polymerizable groups, or both.

[0185] Method for manufacturing a bonded article As shown in FIG. 7, a double-sided tape 610 according to one embodiment of the present disclosure, including curable adhesive free-standing films 640 and 660 adjacent to a single curable foam support layer 650, is applied to a first substrate 630 such that the curable adhesive free-standing film 660 is in contact with the first substrate 630. An activator in the adhesive system of the present disclosure is applied to a second substrate 620 and typically allowed to dry to form an activator layer 670 adjacent to the second substrate 620. After applying the tape and activator to the respective substrates and waiting any desired independently selected amount of time, the activator layer 670 is brought into contact with the curable adhesive free-standing film 640 of the double-sided tape 610. Once the activator layer 670 and the curable adhesive free-standing film 640 are in contact, curing begins and continues through the foam support layer 650 and the curable adhesive free-standing film 660. The tape cures to form a cured structural adhesive layer from the curable adhesive free-standing films 640 and 660 and the cured foam support layer 650. In some embodiments, the assembly is held by an external force, such as a clamp, until the curable adhesive film cures, while in other embodiments, the tackiness of the tape alone holds the assembly until curing. The activator layer 670 can be cured or simply dried in the final cured structure 600, which includes two substrates bonded together by double-sided tape that includes a structural adhesive bond.

[0186] In some embodiments of the adhesive system of the present disclosure, the tape may be attached to the substrate at the time of manufacture and bonded at a different time and / or location. In some embodiments, the tape may be attached to the first substrate at the time of manufacture, and the tape may be optionally covered with a conventional release liner for any period of time before bonding to the activated second substrate. An activator may be applied to the second substrate and allowed to dry at the second manufacturing time, and the first substrate with the tape thereon and the activated second substrate may be bonded at the second manufacturing time, or even at a third time and / or location.

[0187] Advantageously, as shown in the examples below, the tape in the adhesive system of the present disclosure can be applied to a first aluminum substrate, and can be optionally covered with a release liner to prevent any contamination of the surface of the curable adhesive free-standing film. Upon removing the release liner and contacting the curable adhesive free-standing film with a second aluminum substrate having an activator layer, the tape cures and forms a structural adhesive, as evidenced by the overlap shear data in Table 4. Also, as shown in Table 4, the overlap shear strength provided by the adhesive system of the present disclosure remains stable for a period of 3 days up to 6 weeks after the tape is applied to the first aluminum substrate. Thus, it is possible to apply the tape to a substrate at a first time or location and bond it to an activated second substrate at a later time or at a different location, providing flexibility in the manufacture of bonded articles using the adhesive system of the present disclosure.

[0188] Thus, the present disclosure provides a method for producing a bonded article. The method includes applying the tape in any of its embodiments to a first substrate, applying the activator in any of its embodiments to a second substrate, and contacting the tape on the first substrate with the activator on the second substrate to bond the first substrate and the second substrate. In some embodiments, applying the tape is performed at least 1, 3, or 5 days, or at least 1, 2, 3, 4, 5, or 6 weeks before contacting the tape on the first substrate with the activator on the second substrate. In some embodiments, the tape is covered with a release liner, in some embodiments for any of the above times, and the release liner is removed before contacting the tape on the first substrate with the activator on the second substrate. In some embodiments, the activator is allowed to dry before contacting the tape on the first substrate with the activator on the second substrate.

[0189] In another embodiment of the method of manufacturing a bonded article, a tape 510 including a barrier layer 590 as shown in FIG. 5 may be useful. An activator may be used when bonding the tape 510 to a first substrate, for example via a third curable adhesive freestanding film 540'. The layer 540' / 550' / 560' cures to form a cured structural adhesive layer, while the barrier 590 can prevent the layer 540 / 550 / 560 from curing. Another independently selected activator may be used to bond the tape 510 to a second substrate via the first curable adhesive freestanding film 540. The layer 540 / 550 / 560 can then cure to form a structural adhesive layer. This embodiment also allows the tape to be applied to a substrate at a first time or location and bonded to an activated second substrate at a later time or at a different location, providing flexibility in the manufacture of bonded articles using the adhesive system of the present disclosure.

[0190] SELECTED EMBODIMENTS OF THE DISCLOSURE In embodiment 1, A tape comprising a curable adhesive free-standing film adjacent to a curable foam support layer, the curable adhesive free-standing film comprising: a) a film-forming polymer or oligomer; b) a species comprising an unsaturated free-radically polymerizable group, which may be a) or a species other than a), and c) a transition metal cation (in certain embodiments, the curable free-standing film also comprises a redox accelerator); and d) an activator for adhering a curable adhesive free-standing film to a substrate, the activator comprising an oxidizer and being a liquid at ambient temperature and pressure.

[0191] Embodiment 2 is the adhesive system of embodiment 1, wherein the foam is a closed cell, open cell, syntactic, or non-syntactic foam.

[0192] Embodiment 3 is the adhesive system of embodiment 1 or 2, wherein the curable foam support layer comprises a base polymer or oligomer that may be the same or different than the film-forming polymer or oligomer of the curable adhesive free-standing film.Embodiment 4 is the adhesive system of embodiment 3, wherein the curable foam support layer comprises a base polymer or oligomer that is the same as the film-forming polymer or oligomer of the curable adhesive free-standing film.

[0193] Embodiment 5 is the adhesive system of embodiment 3 or 4, wherein the base polymer or oligomer comprises an acrylate or silicone.Embodiment 6 is the adhesive system of embodiment 5, wherein the base polymer or oligomer comprises a poly(meth)acrylate polymer or oligomer.

[0194] Embodiment 7 is the adhesive system of any one of embodiments 1 to 6, where the curable foam support layer comprises a crosslinker therein or where the curable foam support layer comprises a crosslinker that is migratable (from the curable adhesive free-standing film) to the curable foam support layer. Embodiment 8 is the adhesive system of embodiment 7, where the crosslinker is the same or different species containing unsaturated free-radically polymerizable groups as the curable adhesive free-standing film. Embodiment 9 is the adhesive system of embodiment 8, where the crosslinker is the same species containing unsaturated free-radically polymerizable groups as the curable adhesive free-standing film. Embodiment 10 is the adhesive system of embodiment 9, where the curable foam support layer comprises a blowing agent and the same ingredients as the curable adhesive free-standing film. Embodiment 11 is the adhesive system of embodiment 8, where the crosslinker is a species containing unsaturated free-radically polymerizable groups of the curable adhesive free-standing film and migrates and / or has migrated (i.e., has migrated) to the curable support layer.

[0195] Embodiment 12 is the adhesive system of any one of embodiments 3 to 11, wherein the curable foam support layer comprises a blowing agent and a base polymer or oligomer.Embodiment 13 is the adhesive system of embodiment 10 or 12, wherein the blowing agent comprises expandable microspheres, hollow glass bubbles, nitrogen bubbles, optionally surfactant stabilized bubbles formed from physical agitation and stabilized with a surfactant (e.g., a fluorinated surfactant), or a combination thereof.

[0196] Embodiment 14 is the adhesive system of any one of embodiments 1-13, wherein the curable foam support layer further comprises a polymeric modulus modifier.Embodiment 15 is the adhesive system of embodiment 14, wherein the polymeric modulus modifier comprises a polymer having a Tg of 100° C. or less, 90° C. or less, 80° C. or less, 70° C. or less, 60° C. or less, 50° C. or less, or 40° C. or less.Embodiment 16 is the adhesive system of embodiment 15, wherein the polymeric modulus modifier comprises a polyvinyl acetal resin (e.g., polyvinyl butyral).Embodiment 17 is the adhesive system of embodiment 15, wherein the polymeric modulus modifier comprises a high acid polymer.

[0197] Embodiment 18 is the adhesive system of any one of embodiments 1-17, wherein the curable foam support layer further comprises optional additives selected from the group of fillers, antioxidants, viscosity modifiers, pigments, tackifying resins, fibers, flame retardants, antistatic and slip agents, thermally conductive particles, electrically conductive particles, continuous microfibers, filaments, and mixtures thereof. In certain embodiments, the curable foam support layer also comprises a transition metal cation and a redox accelerator, as described herein for the curable adhesive free standing film.

[0198] Embodiment 19 is the adhesive system of any one of embodiments 1-18, wherein the curable foam support layer comprises a filler. Embodiment 20 is the adhesive system of embodiment 19, wherein the filler comprises fumed silica. Embodiment 21 is the adhesive system of embodiment 19, wherein the filler comprises solid or hollow particles. Embodiment 22 is the adhesive system of embodiment 21, wherein the solid or hollow particles comprise a polymer, glass, ceramic, or metal oxide material.

[0199] Embodiment 23 is the adhesive system of any one of embodiments 1-22, wherein the curable foam support layer is hot melt processable.Embodiment 24 is the adhesive system of any one of embodiments 1-23, wherein the curable adhesive free standing film is a hot melt processable adhesive.

[0200] Embodiment 25 is the adhesive system of any one of embodiments 1-24, wherein the curable adhesive free-standing film is carried on the first major surface of the curable foam support layer.

[0201] Embodiment 26 is the adhesive system of any one of embodiments 1-24, wherein the curable adhesive free-standing film is directly bonded (e.g., laminated) to the first major surface of the curable foam support layer.

[0202] Embodiment 27 is the adhesive system of any one of claims 1 to 26, further comprising a barrier film support layer adjacent the surface of the curable foam support layer opposite the curable adhesive free-standing film.

[0203] Embodiment 28 is the adhesive system of any one of claims 1-26, further comprising a second adhesive layer adjacent the surface of the curable foam support layer opposite the curable adhesive free-standing film.

[0204] Embodiment 29 is the curable adhesive free-standing film is a first curable adhesive free-standing film; the tape further comprises a second curable adhesive free-standing film, the second curable adhesive free-standing film comprising a component comprising: a') a film-forming polymer or oligomer; b') a species comprising an unsaturated free-radically polymerizable group, which can be a') or a species other than a'); and c') a transition metal cation; The adhesive system of any one of the preceding embodiments, wherein a second curable adhesive free-standing film is adjacent to the surface of the curable foam support layer opposite the first curable adhesive free-standing film.

[0205] Embodiment 30 is the adhesive system of embodiment 29, wherein a first curable adhesive free-standing film is supported on a first major surface of the curable foam support layer and a second curable adhesive free-standing film is supported on a second major surface of the curable foam support layer.Embodiment 31 is the adhesive system of embodiment 29, wherein a first curable adhesive free-standing film is directly bonded to the first major surface of the curable foam support layer and a second curable adhesive free-standing film is directly bonded to the second major surface of the curable foam support layer.

[0206] Embodiment 32 is the curable adhesive free-standing film is a first curable adhesive free-standing film; the tape further comprises a barrier film support layer and a second curable adhesive free-standing film, the second curable adhesive free-standing film comprising a component comprising: a') a film-forming polymer or oligomer; b') a species comprising an unsaturated free-radically polymerizable group, which may be a species other than a') or a'); and c') a transition metal cation; a barrier film support layer adjacent to a surface of the curable foam support layer opposite the first curable adhesive free-standing film; 25. The adhesive system of any one of the preceding embodiments, wherein a second curable adhesive free-standing film is adjacent to the barrier film support layer on the surface opposite the curable foam support layer.

[0207] Embodiment 33 is the curable adhesive free-standing film is a first curable adhesive free-standing film; the curable foam support layer is a first curable foam support layer; the tape further comprises a barrier film support layer, a second adhesive free-standing film, and a second curable foam support layer, the second curable adhesive free-standing film comprising a component comprising: a') a film-forming polymer or oligomer; b') a species comprising an unsaturated free-radically polymerizable group, which may be a species other than a') or a'); and c') a transition metal cation; a barrier film support layer adjacent to a surface of the first curable foam support layer opposite the first curable adhesive free-standing film; a second curable foam support layer adjacent to a surface of the barrier film support layer opposite the first curable foam support layer; 25. The adhesive system of any one of the preceding embodiments, wherein a second curable adhesive free-standing film is adjacent to the surface of the second curable foam support layer opposite the barrier film support layer.

[0208] Embodiment 34 is the curable adhesive free-standing film is a first curable adhesive free-standing film; the curable foam support layer is a first curable foam support layer; the tape further comprises a barrier film support layer, second, third, and fourth adhesive free-standing films, and a second curable foam support layer; the layers are arranged in the following order: a first curable adhesive free-standing film, a first curable foam support layer, a second curable adhesive free-standing film, a barrier film support layer, a third curable adhesive free-standing film, a second curable foam support layer, and a third curable adhesive free-standing film; 25. The adhesive system of any one of embodiments 1-24, wherein the curable adhesive free-standing film comprises the same or different (i.e., independently selected) components and the curable foam support layer comprises the same or different (i.e., independently selected) components.

[0209] Embodiment 35 is an adhesive system according to any one of embodiments 1 to 34, comprising a barrier film support layer, the barrier film support layer comprising, for example, metal, polyolefin, such as high density polyethylene (HDPE), low density polyethylene (LDPE), linear low density polyethylene (LLDPE), ultra-linear low density polyethylene U-LLDPE and polypropylene (PP); polyvinyl polymer, such as polyvinyl chloride (PVC) and polyvinyl acetate (PVA); polyolefin-based copolymer, such as ethylene-methacrylic acid copolymer (EEMA) and ethylene-vinyl acetate copolymer (EVA); polyurethane; natural or synthetic rubber; block copolymer, such as acrylic block copolymer and styrene-isoprene-vinyl acetate copolymer; polyamide modified polyether, and thermoplastic elastomer (TPE); acrylate resin, such as polymethyl methacrylate (PMMA); polyester, such as polyethylene terephthalate (PET); polycarbonate; norbornene-based resin; and triacetyl cellulose (TAC).

[0210] Embodiment 36 is the adhesive system of any one of embodiments 1-35, wherein the tape has an extensibility of at least 0.5 mils (12.7 micrometers) by the Lang test described in the Examples section.

[0211] Embodiment 37 is the adhesive system of any one of embodiments 1-36, wherein b) is a) in the curable adhesive free standing film.Embodiment 38 is the adhesive system of any one of embodiments 1-36, wherein b) is a species other than a), and a) does not contain an unsaturated free radically polymerizable group.

[0212] Embodiment 38 is the adhesive system of any one of embodiments 1 to 37, wherein the activator comprises a film-forming polymer or oligomer.

[0213] Embodiment 39 is the adhesive system of any one of embodiments 1 to 38, wherein the activator does not include a tackifier, does not include a species containing an unsaturated free radically polymerizable group, or both.

[0214] Embodiment 40 is an adhesive system according to any one of embodiments 1 to 39, wherein the curable adhesive free-standing film comprises an outer surface having embossed air release channels that can aid in the escape of air during application of the outer surface to a substrate.

[0215] Embodiment 41 is a method for producing a bonded article, the method including applying a tape described in any one of embodiments 1-37 or 40 to a first substrate; applying an activator described in any one of embodiments 1, 38, and 39 to a second substrate; and contacting the tape on the first substrate with the activator on the second substrate to bond the first substrate and the second substrate.

[0216] Embodiment 42 is the method of embodiment 41, wherein applying the tape occurs at least 1, 3, or 5 days, or at least 1, 2, 3, 4, 5, or 6 weeks, before contacting the tape on the first substrate with the activator on the second substrate.

[0217] Embodiment 43 is the method of embodiment 41 or 42, wherein the tape is covered with a release liner, and the method further comprises removing the release liner before contacting the tape on the first substrate with the activator on the second substrate.

[0218] Embodiment 44 is the method of embodiment 41 or 42, further comprising applying an activator of any one of embodiments 1, 38, or 39 to the first substrate, and wherein the tape is any one of embodiments 32-35. EXAMPLES

[0219] Objects and advantages of the present disclosure are further illustrated by the following non-limiting 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 the disclosure.

[0220] Unless otherwise stated, all parts, percentages, ratios, etc. in the examples and elsewhere in this specification are by weight.

[0221] [Table 1-1]

[0222] [Table 1-2] [Example]

[0223] Preparation of Acrylate Ester Polymers A terpolymer of isooctyl acrylate / N-vinyl caprolactam / acrylic acid (IOA / NVC / AA) in a weight ratio of 78:20:2 was prepared as follows: To a 237 mL narrow-mouth bottle were added 39 grams (g) of IOA, 10 g of NVC, 1 g of AA, 0.1 g of AIBN, and 75 g of ethyl acetate. The resulting solution was purged with dry argon for 3 minutes and sealed. The sealed bottle was then rotated in a rotating water bath at 55° C. for 24 hours. The conversion was determined to be 99.1% by infrared spectrophotometric analysis. The solution had a viscosity of about 7500 cps. The intrinsic viscosity was determined to be about 0.72 deciliters per gram (dl / g) using the test method described below.

[0224] Preparation of Adhesive Film 1 Adhesive film 1 was made by combining the polymer with the liquid blend. The polymer was prepared as described in Synthesis Example S1 of U.S. Patent Application Publication No. 2013 / 0184394(A1) (Satrijo et al.), except that the pre-adhesive composition was as follows: 89.480 weight percent M1, 9.942 weight percent AA, 0.149 weight percent photoinitiator-1, 0.030 weight percent CuOAc, 0.398 weight percent antioxidant-1, and 0.001 weight percent HDDA. A liquid blend was prepared by adding 132.8 pounds (lb) (60.2 kilograms (kg)) of DTMPTA using a diaphragm pump (Wilden Pump and Engineering, Grand Terrace, CA, USA) to a HM-2.5 basket mill (Hockmeyer Equipment Corporation, Elizabeth City, NC, USA) with 9 spindle hubs preloaded with clean Zirmil 1.5 millimeter (mm) bead media and equipped with a 0.5 mm tungsten coated screen and an HM-2.5 turboprop. Once the addition of DTMPTA was complete, 17.2 lb (7.8 kg) of BTEAC was added to the basket mill using a paddle mixer to incorporate. The mixture was milled at 800 revolutions per minute (rpm) for 3 hours with the cooling jacket set at 70°F (21°C). The ground material was further diluted by adding 254.1 lb (115.3 kg) of DTMPTA for every 45.9 lb (20.8 kg) of ground material. This diluted material, liquid blend, was combined at 28.5 weight percent with 71.5 weight percent of the above polymer as described in Hotmelt Compounding of PSA Adhesive Tape in WO 2021 / 176376 (Kugel et al.) to produce Adhesive Film 1.

[0225] Preparation of Curable Foam Support Layer 1 with High Acid Polymer A curable foam support layer 1 having a high acid polymer (HAP) was made by making a liquid mixture containing the high acid polymer and coating it onto a film. The high acid polymer (having the composition shown in Table 1) was prepared as described below.

[0226] [Table 2]

[0227] Polymerization of the monomers listed in Table 1 was carried out using a Büchi Polycave stainless steel reactor (Büchi Labortechnik GmbH, The Netherlands). The Büchi reactor was charged with 250 grams of a mixture consisting of the monomer mixture and amounts shown in Table 1. The reactor was sealed, purged of oxygen, and then maintained at approximately 1 bar of nitrogen pressure. The reaction mixture was heated to 60°C and the reaction was allowed to proceed adiabatically. The reaction peak temperature was 110°C. Once the reaction was complete, the mixture was cooled to less than 50°C. The polymerization conversion was approximately around 35%. The high acid polymer was then combined in the polymerization precursor containing EHA and AA. During dilution, the resulting composition was mixed and mixing was stopped when the viscosity reached 2000-4500 mPas (measured with a Brookfield viscometer (AMETEK GmbH / BU Brookfield, Hadamar-Steinbach, Germany) using spindle 4 at 12 rpm at a temperature of 25°C). Once the desired viscosity was reached, PI 3, HDDA, DCPA, and FS were added and mixed again. Finally, GB was added and the mixture was stirred with a propeller stirrer (300 rpm) for 5 minutes until they were uniformly dispersed. The exact composition (weight percent) of the liquid mixture is listed in Table 2 below.

[0228] [Table 3]

[0229] A curable foam support layer 1 with high acid polymer was obtained by coating the liquid mixture onto a 75 micron (3 mil) siliconized PET liner (SLVK liner with dimensions of 300 mm x 300 mm) using a dual liner laboratory coater. The line speed of the coater was set at 1 meter per minute (m / min). The resulting thickness was 140 microns (5.5 mils). Curing was accomplished from both the top and bottom sides at a UV curing station with a length of 300 centimeters (cm) at the above line speed. The total irradiation intensity cumulatively irradiated from top to bottom was approximately 3 milliwatts per cubic centimeter (mW / cm 2 ) was.

[0230] Preparation of Curable Foam Support Layer 2 with PVB A curable foam support layer 2 with PVB was prepared by making a liquid mixture and then coating it onto a film. First, a liquid mixture was prepared as described in the adhesive composition of Example 2 of US Patent Application Publication No. 2021 / 0102100 (Xia et al.), except that the composition was as follows: 50.3863 weight percent EHA, 8.3977 weight percent IBOA, 14.2509 weight percent AA, 14.2509 weight percent HEA, 1.1001 weight percent Photoiniator-2, 11.5637 weight percent PVB, and 0.0504 weight percent HDDA. Second, the delivered UV was 4 mW / cm2 for 200 seconds on the top and bottom. 2 The mixture was coated and cured as described in Example 13 of WO 2017 / 112453 (Janoski et al.), except that the total gap setting was adjusted to deliver a final thickness of 0.005 inches (127 micrometers) and the composition was sparged with nitrogen before coating with the stabilizer using an Oakes Foamer (ETOakes Corporation, Hauppauge, NY).

[0231] Preparation of Curable Foam Support Layer 3 Curable Foam Support Layer 3 was prepared as described for Adhesive Film 1, except that its composition was as follows: 67.7 weight percent of the polymer used in preparing Adhesive Film 1, 28.8 weight percent of the liquid blend used in preparing Adhesive Film 1, and 3.5 weight percent of the density modifier. The thickness was 10 mils (0.26 mm).

[0232] Preparation of double-sided tape The multi-layer construction was assembled by placing the curable foam support material face up on a horizontal surface. Adhesive Film 1 was applied by rolling the release liner-attached adhesive film 1 onto the exposed flat surface of the support using a 2-inch (5.1 cm) hard rubber roller (MARSHALLTOWN, Marshalltown, IA). After initial contact was made, the rubber roller was used to roll over the entire surface to minimize air bubbles between the curable foam support and adhesive film 1 and ensure complete contact. This process was repeated on the other side of the support so that both sides of the support were facing adhesive film 1. This process was performed for each of the curable foam support layers 1, 2, and 3, and PE.

[0233] Preparation of Multilayer Tape of Example 5 A three-layer coextruded tape was prepared by coextruding a first and a second curable adhesive free-standing film layer on either side of a curable support layer. The composition of the curable foam support layer was 68.74 weight percent of the polymer used in preparing adhesive film 1, 28.5 weight percent of the liquid blend used in preparing adhesive film 1, 2.00 weight percent of a density modifier, and 0.76 weight percent of BP. The composition of the first and second curable adhesive free-standing films was 70.71 weight percent of the polymer used in preparing adhesive film 1, 28.5 weight percent of the liquid blend used in preparing adhesive film 1, and 0.79 weight percent of BP. The total thickness of the tape from the three-layer multi-manifold film die was 12 mils (0.30 mm). The three-layer coextruded tape was cast between a silicone-coated casting roll and a silicone-coated paper liner that was captured by a second chill roll. The chill roll was cooled with water at a temperature of about 13°C. Once cooled, the coextruded tape was released from the silicone release coated roll, thereby adhering to a silicone coated paper liner, which was then wound up at a winding station.

[0234] Preparation of activator An activator was prepared as described in Example 1 of WO 2021 / 176376 (Kugel et al.), except that the composition was as follows: 4.0 weight percent TBEC and 96.0 weight percent UPUV.

[0235] Preparation of the activator used in Example 5 A 5-liter flask equipped with overhead stirring, thermocouple, condenser, and nitrogen inlet was charged with 100.0 grams of Polymer 2, 0.15 grams of OB, 48.0 grams of ATBC, 120.0 grams of acrylic ester polymer, and 4.0 grams of SI. Stirring was started, 2090 grams of heptane was added, and the mixture was heated at 60° C. for 3 hours to ensure a homogenous solution. The solution was cooled to ambient temperature and then sequentially diluted with 1710 grams of methyl acetate and 301.1 grams of TBEC. The final solution was found to have a solids content of 11.65 weight percent.

[0236] Test Method intrinsic viscosity Intrinsic viscosity was measured by conventional means by measuring the flow time of 10 mL of polymer solution (0.15 g of polymer per deciliter of ethyl acetate) using a Cannon-Fenske #50 viscometer in a water bath controlled at 25°C.

[0237] Dynamic Shear Adhesion Test Dynamic overlap shear testing was performed at 71°F (22°C) using an Insight 30EL load frame (MTS, Eden Prairie, MN). The specimen was attached to the grips and the crosshead was operated at 10 inches (25.4 cm) per minute to load the specimen to failure. The breaking stress was recorded in pounds per square inch (psi) using the test method disclosed in ASTM D1002. Six specimens were prepared and an average was taken and recorded. The adhesive failure mode was recorded as cohesive, adhesive, or 2-bond. Cohesive failure is defined as failure within the curable foam support layer that separates the foam. Adhesive failure is defined as failure between adhesive film 1 and the substrate. 2-bond failure is defined as interlaminar failure between adhesive film 1 and the curable foam support layer.

[0238] Lung extensibility test A 3 inch by 11 inch by 0.25 inch (7.6 cm by 27.9 cm by 6.5 mm) acrylic substrate was cleaned with IPA. A Fineness of Grind Gauge No. 65 (Paul N. Gardner Company, Pompano Beach, FL) was cleaned with MEK. Coupons were made by cutting strips of double-sided adhesive tape measuring 1 inch by 6 inches (2.5 cm by 15.2 cm). The strip was then applied to the acrylic substrate such that the edges of the strip were 0.5 inches (1.3 cm) from the sides and 0.5 inches (1.3 cm) from the ends of the acrylic substrate. The rubber roller described above was used to remove any air bubbles and ensure contact of the entire strip with the acrylic substrate. After removing the release liner from the adhesive strip, the acrylic substrate with adhesive was gently applied adhesive side down to a Fineness of Grind Gauge. Application was made so that the strip filled the 0.5 inch (1.3 cm) gap on the right side of the gauge and the adhesive edge was aligned with the shallow end of the gauge centered on the long edge of the adhesive along the length of the gauge (i.e., 0.25 inch (0.64 cm) of adhesive on either side of the gap). The stack was inserted into an air-driven hydraulic press (Fred S. Carver, Inc. Hydraulic Equipment, Menomonee Falls, WI) and sandwiched, acrylic side up, between two rubber gaskets. The shallow end of the gauge was aligned flush with the backside of the press plate and the adhesive strip was centered over the center of the press plate. With the sample in place, the press was set to 20 psi, run, and held for 5 minutes. Ignoring any air bubbles less than 0.13 inch (0.32 cm) in diameter, the reported value is the point where the adhesive transitions from contact to non-contact, read in "mils" on the markings on the side of the gauge, and estimated to the nearest 1 / 2 mil. Three specimens were prepared and the average was taken and reported.

[0239] FTIR Transition Test Fourier transform infrared spectroscopy in attenuated total reflectance (ATR) mode was utilized to monitor the migration of the curable components to the support layer at room temperature. The samples used for testing were prepared by first laminating Adhesive Film 1 to one side of one of the curable foam support layers discussed above. For measurements, a 0.5 inch (1.3 cm) wide strip of the test sample was directly applied, Adhesive Film 1 side, and laminated over one quarter of a 2 inch long multi-bounce zinc selenide (ZnSe) ATR crystal with an incidence angle of 45 degrees. To ensure complete contact, the film was gently pressed by hand to displace air from the interface between the crystal and the adhesive. For each scan, data was captured for a new piece from the sample laminate, and the time interval between the scan and the time of lamination was recorded. 1726 cm -1 The absorbance of the carbonyl group at 1380 cm was used as a measure for normalization between samples measured at different times. -1 (1355cm -1 and 1428cm -1 The absorbance at 810 cm (a two-point baseline was applied between 810 cm and 810 cm) was found to be unchanged for all scans and independent of the transition, which was used as a measure of normalization. -1 (795 and 826 cm -1 The change in peak area associated with the reactive double bond absorbance of the acrylate group from the migrating component at 810 cm (a two-point baseline between 810 cm and 820 cm was applied) was measured for each scan. Evidence of migration was observed at 810 cm under consecutive observation days. -1 The peak area was determined by the decrease in

[0240] Working Example Examples for dynamic shear adhesion were prepared using 1 inch x 4 inch x 0.064 inch (2.5 cm x 10 cm x 1.6 mm) aluminum substrates that had been washed three times with MEK, then a 50 / 50 water / IPA solution, then acetone, followed by air drying for at least 2 minutes. The substrates were then activated with activator. Activation was accomplished by folding a small laboratory wipe three times to create an approximately 1 inch strip, dipping this into the activator solution, and wiping from the edge to the center of the substrate so that approximately 2 inches were coated. The activated substrates were allowed to air dry for a minimum of 2 minutes before applying the adhesive. Coupons were made by cutting 1 inch (2.5 cm) strips of the double-sided tape described above. One liner was removed and the double-sided tape was placed over the activated portion of the substrate. A 2 inch (5.1 cm) stiff rubber roller (MARSHALLTOWN, Marshalltown, IA) was used to ensure complete contact of the adhesive. A bond was formed by removing the top release liner to expose the adhesive and introducing it to a second activated substrate. The closed bond was then subjected to application of approximately 50 lbf (222 N) of pressure and the bonded test assembly was left at room temperature (71° F. (22° C.)) for 7 days before testing. Using this format, Example 1 was made from a double-sided tape made from curable backing layer 1, Example 2 was made from a double-sided tape made from curable backing layer 2, and Example 3 was made from a double-sided tape made from curable backing layer 3. Comparative Example 1 was made in this manner using a double-sided tape made from PE. Example 4 was made by applying Example 1 to both sides of PET, thereby producing the structure shown in FIG. 5.

[0241] The Lang test and FTIR migration examples used the same nomenclature (e.g., Curable Foam Support Layer 1 corresponds to Example 1), except that the sample preparation for each test is described in the corresponding test method description for those tests, and the tests were performed without activator (i.e., on uncured tape).

[0242] Sample preparation for Example 5 Examples for dynamic shear adhesion were prepared using 1 inch x 4 inch x 0.064 inch (2.5 cm x 10 cm x 1.6 mm) aluminum substrates that had been cleaned three times with MEK, then a 50 / 50 water / IPA solution, then acetone, followed by air drying for at least 2 minutes. Coupons were made by cutting 1 inch (2.5 cm) strips of the multilayer tape of Example 5 described above. The strip of tape was placed across the cleaned aluminum substrate and trimmed flush with the edge of the substrate to form a 1 inch x 1 inch bond area. A 2 inch (5.1 cm) stiff rubber roller (MARSHALLTOWN, Marshalltown, IA) was used to ensure complete adhesive contact. These coupons were allowed to sit at room temperature (71°F (22°C)) for the lengths of time indicated in Table 4. After the sitting period, a second set of substrates was cleaned as described above and activated with the activator of Example 5. Activation was performed by folding a small laboratory wipe three times to create an approximately 1 inch strip, dipping this into the activator solution, and wiping from the edge to the center of the substrate so that approximately 2 inches were coated. The activated substrates were allowed to air dry for a minimum of 2 minutes before forming a bond. A bond was then formed by removing the top release liner of the rested specimen to expose the adhesive, which was then introduced to a second activated substrate. The closed bond was then subjected to the application of approximately 50 lbf (222 N) of pressure, and the bonded test assembly was allowed to rest at room temperature (71° F. (22° C.)) for 3 days before testing. The final structure is shown in FIG. 7. The tape structure of Example 5 was made as described in Preparation of the Multilayer Tape of Example 5, and a dynamic shear adhesive bond was made by activating only one substrate, thereby producing the structure shown in FIG. 7.

[0243] [Table 4]

[0244] In Comparative Example 1, the failure mode indicates that the migrating crosslinker did not migrate across the interface and become part of the curable support layer. Figure 6 shows that Examples 1, 2, and 4 have significant migration of crosslinker from the curable adhesive freestanding film to the curable foam support layer. Example 3 shows no migration because the curable foam support layer of that example is already saturated with crosslinker. Comparative Example 1 shows no substantial migration of crosslinker, demonstrating the importance of migration to performance in some embodiments.

[0245] [Table 5]

[0246] All references, patents, and patent applications cited in the above application for Letters Patent are incorporated herein by reference in their entirety for consistency. In the event of any inconsistency or discrepancy between any of the incorporated references and this application, the information in the foregoing description shall prevail. The foregoing description is intended to enable one skilled in the art to practice the disclosure as set forth in the claims, and should not be construed as limiting the scope of the present disclosure, which is defined by the claims and all equivalents thereof.

Claims

1. 1. A tape comprising a curable adhesive free-standing film adjacent to a curable foam support layer, said curable adhesive free-standing film comprising: a) a film-forming polymer or oligomer; b) a species comprising an unsaturated free-radically polymerizable group, which may be a) or a species other than a); c) a transition metal cation; and a tape, 1. An activator for adhering a curable adhesive free-standing film to a substrate, comprising: d) Oxidizing Agent an activator which is liquid at room temperature and pressure; 1. An adhesive system comprising:

2. 10. The adhesive system of claim 1, wherein the foam is at least one of a closed-cell foam or a syntactic foam.

3. 10. The adhesive system of claim 1, wherein the curable foam support layer comprises a base polymer or oligomer that may be the same as or different from the film-forming polymer or oligomer of the curable adhesive free-standing film.

4. The adhesive system of claim 3 wherein the base polymer or oligomer comprises a poly(meth)acrylate polymer or oligomer.

5. The adhesive system of claim 1 , wherein the curable foam support layer comprises a crosslinker within the curable foam support layer.

6. 6. The adhesive system of claim 5, wherein said crosslinker is different from said unsaturated, free-radically polymerizable group-containing species of said curable adhesive free-standing film.

7. 6. The adhesive system of claim 5, wherein the crosslinker is a species containing the unsaturated free-radically polymerizable groups of the curable adhesive free-standing film and migrates to the curable support layer.

8. 10. The adhesive system of claim 1, wherein the curable foam support layer further comprises a polymeric modulus modifier comprising a polymer having a Tg of 100°C or less.

9. 9. The adhesive system of claim 8, wherein the polymeric modulus modifier comprises a polyvinyl acetal resin.

10. The adhesive system of claim 8 , wherein the polymeric modulus modifier comprises a high acid polymer.

11. The adhesive system of claim 1 , wherein the curable foam support layer is hot melt processable.

12. 10. The adhesive system of claim 1, wherein the curable adhesive free standing film is a hot melt processable adhesive.

13. 10. The adhesive system of claim 1, wherein the curable adhesive free-standing film is carried on or directly bonded to a first major surface of the curable foam support layer.

14. 10. The adhesive system of claim 1, further comprising a barrier film support layer adjacent the surface of the curable foam support layer opposite the curable adhesive free-standing film, or a second adhesive layer adjacent the surface of the curable foam support layer opposite the curable adhesive free-standing film.

15. the curable adhesive free-standing film is a first curable adhesive free-standing film; The tape further comprises a second curable adhesive self-supporting film, the second curable adhesive self-supporting film comprising: a') a film-forming polymer or oligomer; b') a species containing an unsaturated free-radically polymerizable group, which can be a species other than a') or a'); c') a transition metal cation; and Contains ingredients including 14. The adhesive system of any one of claims 1 to 13, wherein the second curable adhesive free-standing film is adjacent to the surface of the curable foam support layer opposite the first curable adhesive free-standing film.

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