Heat initiated debondable coatings

Abstract

At a high level, the present disclosure is directed to heat-initiated debondable attachment articles that include a first substrate, a first debondable coating made of a blend of thermoplastic polymers, and a first adhesive layer. The first debondable coating is applied directly to the first substrate, and the adhesive layer is applied directly to the debondable coating. Optionally, a second substrate is present, in direct contact with the first adhesive layer. The thermoplastic polymers in the blends are independently selected polyesters, preferably co-polyesters. The first adhesive layer is a curable adhesive, preferably a 2-part adhesive. In preferred embodiments, the article does not include a porous support layer and may optionally contain a toughener and / or an adhesion promoter in the debondable coatings.

Description

PA103197W003HEAT INITIATED DEBOND ABLE COATINGSTechnical Field

[0001] The disclosure relates to heat-debondable attachment articles. The present disclosure further relates to a part assembly comprising the heat-debondable attachment article. The present disclosure also relates to a method for bonding and debonding an assembly. Moreover, the present disclosure further relates to a use of the heat-debondable article in the manufacture of recyclable articles, in particular of vehicle parts or battery parts.Background

[0002] Adhesives have been used in many structural applications. Such structural applications have included vehicles assembly like automobile and aircraft assembly. For example, epoxy-based adhesives are well stablished in those applications. This also applies in increasing extent in the manufacture of the presently quick-growing technical field of manufacturing batteries for the mobile electrification such as the automotive electrification. As common with these adhesive, very strong bonds between substrates, i.e. permanent bonds are generally desired and achieved.

[0003] However, it may become desirable in numerous applications to release the bond between different parts in devices or in certain assemblies. This is in particular true when there is a desire to dissemble said parts or assemblies for in order to recycle at least parts thereof.

[0004] Therefore, there exist an increasing desire in the art for adhesive or bonding technologies which provide not only good bonds between parts, but also enable the debonding of parts at a point when desired.Summary

[0005] The present disclosure provides a heat-initiated debondable attachment article, comprising• a first substrate,• a first debondable coating on the first substrate and having a first major surface immediately adjacent the first substrate and a second major surface, and comprising a first blend of thermoplastic polymers;• a first adhesive layer immediately adjacent the second major surface of the first debondable coating;• optionally a second debondable coating having a first major surface and a second major surface, with the first major surface being immediately adjacent the first adhesive and the second major surface being immediately adjacent a second substrate, and comprising a second blend of thermoplastic polymers; wherein the first blend and the second blend of thermoplastic polymers each comprise at least a first thermoplastic polymer and a second thermoplastic polymer, wherein the first thermoplastic polymer and the second thermoplastic polymer of the first blend are independently selected from the first thermoplastic polymer and the second thermoplastic polymer of the second blend,wherein the first adhesive layer comprises a curable adhesive, preferably a 2-part adhesive, wherein the attachment article does not have a porous support layer, wherein the first thermoplastic polymer and the second thermoplastic polymer are each independently chosen from polyesters, wherein the first debondable coating and / or the second debondable coating optionally comprises at least one toughener.

[0006] The present disclosure further provides a die-cut, comprising the heat-debondable attachment article.

[0007] Also, the present disclosure relates to a methods for bonding and debonding a part assembly. In some embodiments, the method for bonding comprising the following steps:• applying a first debondable coating as recited in any one of embodiments in this disclosure at least part of a surface of a first part;• applying a first adhesive layer to either a portion of a surface of a second part or a surface of the first debondable coating coating;• Attaching the second part to the first part such that the first debondable coating and the first adhesive layer connect the first part to the second part, thereby forming a part assembly;• allowing the at least one first adhesive to cure.

[0008] In other embodiments, the method for debonding comprising the following steps:• providing a part assembly comprising a first part bonded to a second part, and further comprising at least a first debondable coating,• heating the part assembly so as to soften and / or at least partially melt the first debondable coating and / or second debondable coating;• disconnecting the second part from the first part.

[0009] Furthermore, the present disclosure relates to a use of the heat-debondable article in the manufacture of recyclable articles, in particular of vehicle parts or battery parts.

[0010] It is to be understood that the disclosure is not limited in its application to the details of construction and the arrangement of components set forth in the following description. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. As used herein, the term “a”, “an”, and “the” are used interchangeably and mean one or more; and “and / or” is used to indicate one or both stated cases may occur, for example A and / or B includes, (A and B) and (A or B). Also herein, recitation of ranges by endpoints includes all numbers subsumed within that range (e.g., 1 to 10 includes 1.4, 1.9, 2.33, 5.75, 9.98, etc.). Also herein, recitation of “at least one” includes all numbers of one and greater (e.g., at least 2, at least 4, at least 6, at least 8, at least 10, at least 25, at least 50, at least 100, etc.). Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. Contrary to the use of “consisting”, which is meant to be limiting, the use of “including,” “containing”, “comprising,” or “having” and variations thereof is meant to be not limiting and to encompass the items listed thereafter as well as additional items.Furthermore, it is understood that the term “comprise” as used herein may also embrace the term “consists of’ in the sense of “consists only of’, but in general is used according to its meaning generally used in the art. Hence, limiting down “comprise” to “consists of’ or “comprising” to “consisting of’ is fully embraced in the present disclosure.

[0011] Amounts of ingredients of a composition may be indicated by % by weight (or “% wt”. or “wt.-%”) unless specified otherwise. The amounts of all ingredients gives 100 % wt unless specified otherwise. If the amounts of ingredients is identified by % mole the amount of all ingredients gives 100% mole unless specified otherwise.

[0012] The term “polymer” will be understood to include polymers, copolymers (e.g., polymers formed using two or more different monomers), oligomers and combinations thereof, as well as polymers, oligomers, or copolymers that can be formed in a miscible blend. Polymers include those polymerized in- situ from monomers as well as those materials that exist in a polymeric form independent of the processes used to create them. In this context, the term “polyester” used to refer to the first and second thermoplastic polymers includes polyesters made from polyesters monomers as well as co-polyesters, formed using two or more different polyester monomers. In this context, copolyesters are preferred.

[0013] The term “adjacent” refers to the relative position of two elements, such as, for example, two layers, that are close to each other and may or may not be necessarily in contact with each other or that may have one or more layers separating the two elements as understood by the context in which “adjacent” appears.

[0014] The term “immediately adjacent” refers to the relative position of two elements, such as, for example, two layers, that are next to each other and in contact with each other and have no intermediate layers separating the two elements.

[0015] The term "adhesive" as used herein refers to polymeric compositions useful to adhere together two components (adherents).

[0016] In the context of the present disclosure, the terms “room temperature” and “ambient temperature” are used interchangeably and refer to a temperature of 23 °C at ambient pressure condition of about 101 kPa.

[0017] Unless explicitly stated otherwise, all embodiments and optional features of the present disclosure can be combined freely.Brief Description of the Figures

[0018] FIG. 1 shows a representative a heat-initiated debondable attachment article according to the present disclosure.

[0019] FIG. 2 shows workflow used to test repair properties of articles bonded with the coatings of this disclosure.

[0020] FIGs. 3A, 3B and 3C show photographs of test panels having a coating according to this disclosure prior to bonding and also after debonding.Detailed Description

[0021] At a high level, in some embodiments, the present disclosure is directed to heat-initiated debondable attachment articles that include a first substrate, a first debondable coating made of a blend of thermoplastic polymers, and a first adhesive layer. The first debondable coating is applied directly to the first substrate, and the adhesive layer is applied directly to the debondable coating. Optionally, a second substrate is present, in direct contact with the first adhesive layer. The thermoplastic polymers in the blends are independently selected polyesters, preferably co-polyesters. The first adhesive layer is a curable adhesive, preferably a 2-part adhesive. In preferred embodiments, the article does not include a porous support layer and may optionally contain a toughener and / or an adhesion promoter in the debondable coatings.

[0022] In this disclosure, we refer to the coatings of this disclosure as either debondable coatings or as debondable layers. Both terms refer to the same item.

[0023] This article may be attached to surfaces by means of pressure and / or heat, thereby providing ample adhesive bonds between surfaces, i.e. different parts or articles. However, upon application of heat, the at least one thermoplastic polymer in the at least one first debondable layer may be caused to at least soften or partially melt. This has the effect of weaken the bond sufficiently to be released, usually with the application of certain physical means such as wedges or simply moving the parts in different directions. By this means, a reliable bonding and debonding of parts and articles has surprisingly been achieved. In addition, the article may easily be attached onto a surface of a first substrate such as by means of heat and / or pressure. Then, this assembly may be further processed, stored and / or shipped, until a second substrate is attached to the assembly, e.g. by means of an adhesive. This is highly advantageous in a number of applications in industrial manufacturing processes.

[0024] At least one of the first thermoplastic polymer and the second thermoplastic polymer comprise a blend of at least two different polymers. One of those at least two different polymers preferably exhibits a glass transition temperature in the range of from 20°C to 55 °C, preferably from 25°C to 55 °C, and more preferably from 35 °C to 50 °C, and even more preferably from 35 to 45 °C. The second polymer forming the blend of at least two different thermoplastic polymers preferably exhibits a glass transition temperature in the range of from greater than 55 °C to 100°C, preferably from 55°C to 80 °C, and more preferably from 55°C to 75 °C, and even more preferably from 55°C to 70 °C. The Tg was measured using a differential scanning calorimeter (DSC), with a temperature increase rate of 10°C / min (see DIN 53 765). The inventors have found that the use of at least these two types of polymers has the effect that the blend of polymers at least partially melts upon application of heat, and therefore the article loses at least some of its stability, i.e. its bonding properties. This enables the desirable debonding as described herein. Provided the polymers meet the restrictions on glass transition temperature above, each of the at least two different polymers is advantageously independently selected from polyesters, poly(meth)acrylates, acrylonitrile butadiene styrenes, polyamides, polybenzimidazoles, polycarbonates, polyether sulfones, polyoxymethylenes, polyether ether ketones, polyetherimides, polyethylenes, polyphenylene oxides, polyphenylene sulfides, polypropylenes, polystyrenes, polyvinyl chlorides, and any combinations thereof, preferably polyesters. Inthis regard, it is preferred that the each of the at least two different polymers independently exhibits a number average molecular weight determined by titration method in the range of from 5,000 to 50,000 g / mol, preferably from 7,000 to 40,000 g / mol, and more preferably from 8,000 to 30,000 g / mol.

[0025] In particular, in some embodiments, the at least first thermoplastic polymer has a molecular weight from 5,000 g / mol to 15,000 g / mol, preferably from 7,000 to 15,000 g / mol, and more preferably from 8,000 to 15,000 g / mol, even more preferably from 10,000 g / mol to 15,000 g / mol. In other embodiments, the at least second thermoplastic polymer has a molecular weight from 15,500 g / mol to 50,000 g / mol, preferably from 15,500 to 40,000 g / mol, and more preferably from 15,500 to 30,000 g / mol, even more preferably from 15,500 g / mol to 20,000 g / mol.

[0026] Unless specified otherwise, molecular weight in this disclosure refers to average number molecular weight (Mn) and is calculated based on the final hydroxyl number and acid number contained. For Hydroxyl value / OH value: Refer to DIN 53 240-02. Magnesium hydroxide equivalent to the hydroxyl content per gram of sample, in mg KOH / g. The acid value of the solution product was measured as 100% solids resin; Acid value: Refer to DIN EN ISO 2114. The amount of potassium hydroxide needed to neutralize the acidic substance in 1g sample, in mg KOH7g. The acid value of the solution product is measured as 100% solids resin.

[0027] The debondable coatings of this disclosure can be used to bond two substrates by means of the first adhesive. In preferred embodiments, the coating is present on one of the substrate only. In the bonded article, the adhesive is in contact (immediately adjacent) the debondable coating on one side and one of the substrates on the other side. The other substrate is immediately adjacent to the side of the debondable coating not adjacent the adhesive.

[0028] FIG. 1 shows an exemplary attachment article according to this disclosure. The article includes a first substrate (110), a first debondable coating (120), a first adhesive layer (130), and optionally a second substrate (140). Numerical values in FIG. 1 are only exemplary to illustrate how a specific embodiment could be dimensioned, but do not represent limitations on the dimensions that other embodiments of this disclosure can have.

[0029] It is contemplated that in certain circumstances the debondable layer may be coated on both substrates. Any statements made in this disclosure regarding the first debondable coating apply equally to the optional second debondable coating.

[0030] It is further preferred that the at least one first debondable layer and / or the at least one second debondable layer comprises at least one toughener and / or an adhesion promoter. The inventors have found that the presence of the toughener improves adhesive performance such as improved overlap shear strength and / or tensile strength at room temperature without compromising the performance at the maximum service temperature. Furthermore, this will have the effect of a reduced brittleness of the first and / or second debondable layer. Preferably, the at least one toughener is selected from butadiene rubbers, nitrile rubbers, and core-shell rubbers, more preferably from core-shell rubbers. Exemplary compounds which may be advantageously used as butadiene rubbers or nitrile rubbers are carboxyl-, amine-, epoxy-, hydroxyl- or methacrylate-terminated butadiene, butadiene styrene or butadiene acrylonitrile copolymers, preferablyamine terminated butadiene styrene or butadiene acrylonitrile copolymers. Such tougheners are commercially available, for example, under the trade designations Hypro CTBN, ATBN, ETBN, HTB or VTBNX from CVC Thermoset Specialities and Hycar ATBN from Amerald Materials, or of the MX Series from Kaneka such as MX 257.

[0031] With regard to the core-shell rubber as toughener, any core-shell rubber toughener commonly known in the art may be used in the context of the present disclosure. In a typical embodiment, the coreshell rubber toughener is a composite material configured by materials where the core portion on the inside and the shell portion on the outside are mutually different. Herein, the term "different materials" refers to materials where the composition and / or properties are mutually different, and therefore includes materials where the same type of resins are used but the molecular weights are mutually different, and the like.

[0032] From the perspective of favorably achieving a toughening effect on the compositions as described herein, the Tg of the shell portion is preferably higher than the Tg of the core portion. In this case, while flexibility is provided to the cured epoxy adhesive because the core portion which has a relatively low Tg functions as a centralized point of stress, the shell portion suppresses unwanted agglomeration of the core-shell rubber, and thus the core-shell toughener can be uniformly dispersed in the compositions as described herein.

[0033] Examples of the core-shell rubber toughener include methyl methacrylate - butadiene copolymer, methyl methacrylate - butadiene - styrene copolymer, methyl methacrylate - acrylonitrile - butadiene - styrene copolymer, methyl methacrylate - acrylic rubber copolymer, methyl methacrylate - acrylic rubber - styrene copolymer, methyl methacrylate - acrylic butadiene rubber copolymer, methyl methacrylate - acrylic butadiene rubber - styrene copolymer, methyl methacrylate - (acrylic silicone IPN rubber) copolymer, and the like, but are not restricted thereto. Methyl methacrylate - butadiene copolymer, methyl methacrylate - butadiene - styrene copolymer, and methyl methacrylate - acrylic butadiene rubber - styrene copolymer can be advantageously used as the core -shell toughening agent.

[0034] The core-shell toughener is normally in the form of fine particles, and the average value (weight average particle diameter) of the primary particle diameter thereof is generally approximately 0.05 micrometers or higher or approximately 0.1 micrometers or higher to approximately 5 micrometers or lower or approximately 1 micrometer or lower.

[0035] Preferably, the core-shell rubber can be used in a state dispersed in a matrix. It is preferred that the matrix is an epoxy resin. A matrix with favorable affinity to either first or second epoxy resin as described herein is particularly preferable from the perspective of favorable dispersion of the core-shell rubber in the composition as described herein. Examples of the matrix can include epoxy resins (such as bisphenol A and the like).

[0036] The core-shell toughener can be a commercial product that is provided as a resin modifying agent or the like, and examples include BTA 751 (commercially available from Dow Chemical) as a methyl methacrylate-butadiene-styrene (MBS) type core-shell resin, MX-153 (commercially available from Kaneka) as a resin where methyl methacrylate-butadiene-styrene (MBS) dispersed in bisphenol A diglycidyl ether), and MC-257 (commercially available from Kaneka) as a butadiene core-shell resin,dispersed in epoxy, and F351 (commercially available from Aika Industries) as the acrylic core-shell resin, Paraloid 2650A (butadiene rubber), Hycar ATBN (CVC Chemicals, liquid butadiene rubber), and the like.

[0037] With regard to the effects brought about the presence of the at least one first toughener in the compositions as described herein, it is preferred that the at least one toughener is contained in the at least one first debondable layer in an amount in the range of from 1 to 25 wt.-%, preferably from 2.5 to 20 wt.- %, and more preferably from 5 to 15 wt.-%, based on the total weight of the at least one first debondable layer. Similarly, it is preferred that the at least one toughener is contained in the at least one second debondable layer in an amount in the range of from 1 to 25 wt.-%, preferably from 2.5 to 20 wt.-%, and more preferably from 5 to 15 wt.-%, based on the total weight of the at least one second debondable layer.

[0038] Moreover, with regard to the effects described herein, it is preferred that the at least one first debondable layer exhibits a thickness in the range of from 1 to 300 micrometers, preferably from 3 to 250 micrometers, and more preferably from 5 to 200 micrometers. Similarly, it is preferred that the at least one second debondable layer exhibits a thickness in the range of from 1 to 300 micrometers, preferably from 3 to 250 micrometers, and more preferably from 5 to 200 micrometers.

[0039] In particularly preferred embodiments, the thickness of the debondable coating is in the range of a primer coating. The inventors have discovered that the thickness of the debondable layer can be significantly reduced with respect to previous coatings and that a porous support layer is not needed.

[0040] In preferred embodiments, the thickness of the first debondable coating and the optional second debondable coating can vary independently from each other. In some embodiments, the thickness range for these coatings is from 1 micron to 30 microns. More specifically, several embodiments provide narrower ranges for the thickness, such as from 1 micron to 25 microns, from 1 micron to 20 microns, from 1 micron to 10 microns, from 5 micron to 25 microns, from 5 micron to 20 microns, and from 5 micron to 10 microns.

[0041] The complete article, including the adhesive layer may advantageously exhibit a total thickness in the range of from 40 to 500 micrometers, preferably from 70 to 450 micrometers, and more preferably from 90 to 400 micrometers. Alternatively, the complete article may advantageously exhibit a total thickness in the range of from 40 to 500 micrometers, preferably from 70 to 450 micrometers, and more preferably from 90 to 400 micrometers.

[0042] The heat-debondable attachment article according to the present disclosure may further comprise a first adhesive layer disposed on at least part of the second major surface of the first debondable layer. This may add to ease of application and / or enhancing the adhesive properties of the article. Similarly, the heat-debondable attachment article according to the present disclosure may further comprise a second adhesive layer covering the second major surface of the second debondable layer. Preferably, the first adhesive layer and / or the second adhesive layer comprises at least one adhesive selected from structural adhesives, semi-structural adhesives, and pressure sensitive adhesives, preferably pressure sensitive adhesives.

[0043] In certain embodiments the attachment article as described herein comprises perforations. In this regard, it is preferred that either or both first and second debondable layer comprise perforations. Thismay have the effect of effectively encapsulate the heat-initiated debondable layer, which enhances the bonding and debonding capabilities of the article as described herein. Alternatively, the perforations may extend through the complete thickness of the article from the first major surface to the second major surface. It is further preferred that at least a portion of the article comprises perforations. Thereby, adhesive bonding and debonding properties may be distributed as desired over the length or over certain areas of the article as described herein.

[0044] Preferably, the article provides an overlap shear strength for the debondable portion of the article at a temperature range from -40°C to 60 °C higher than 6.5 MPa, for example in the range of from 6.5 to 25 MPa or from 6.5 to 10 MPa and less than 5 MPa, preferably less than 3 MPa, and more preferably less than 1.5 MPa at a temperature in the range of from 80 to 100 °C.

[0045] Preferably, the article provides Floating Roller Peel at a temperature range between -40°C to 60 °C in the range of from 80 N / 2.5 cm to 250 N / 2.5 cm and less than 55 N / 2.5 cm, preferably less than 50 N / 2.5 cm, and more preferably less than 45 N / 2.5 cm and even more preferably less than 35 N / 2.5 cm at a temperature in the range of from 80 to 100 °C.

[0046] The present disclosure further provides a part assembly having a first end and a second end, comprising a first part, a second part, and the heat-initiated debondable attachment article as described herein wherein the first and second substrates are the first and the second parts of the assembly respectively. The first and the second part may be selected from a great variety of shapes and materials. For instance, they may be selected from metal or composite panels as used in vehicle bodies or in aerospace interior or exterior parts. Also, in an advantageous embodiment of the present disclosure, they may be selected from battery casing parts, i.e. one of first and second parts may be a battery casing, and the other part may be a battery lid or the like. This contributes advantageously to the recyclability of a battery system. It is further preferred that the part assembly further comprises at least one adhesive disposed between the attachment article and the at least one first part and / or the at least one second part.

[0047] The at least one adhesive is preferably selected from structural adhesives and semistructural adhesives, such as from two-components structural adhesives. Advantageously, the heat-initiated debondable attachment article bonds the first panel and second parts together. The part assembly may comprise the attachment article in the complete length between the first end and the second end. Alternatively, the attachment article may be disposed only close to the first end and / or close to the second end. This may bring the advantage that only in this position a first cleavage between first and second part may be achieved, which then compromises the bond between the first and second part on the complete length. Thus, an easy debonding may be achieved, with strong or even very strong bonds on the major length of the bond between first and second part where, for example, a strong structural adhesive may be employed. For example, the attachment article may be disposed at a length in the range of from 0.1 to 30 cm, preferably from 0.2 to 20, more preferably from 0.3 to 15 cm starting from the first end and / or from the second end of the part assembly.

[0048] Another aspect of the present disclosure is a method for bonding a part assembly, the method comprising the following steps:• applying a first debondable coating of this disclosure onto at least part of a surface of a first part;• applying a first adhesive layer to either a portion of a surface of a second part or a surface of the first debondable coating coating;• attaching the second part to the first part such that the first debondable coating and the first adhesive layer connect the first part to the second part, thereby forming a part assembly;• allowing the at least one first adhesive to cure.

[0049] In other embodiments, a method for debonding a part assembly is described, the method comprising the following steps:• providing a part assembly comprising a first part bonded to a second part, and further comprising at least a first debondable coating,• heating the part assembly so as to soften and / or at least partially melt the first debondable coating and / or second debondable coating;• disconnecting the second part from the first part.

[0050] The attaching step comprises the activation of the adhesive layer so that the first and second parts are bonded together. Preferably, the material of the first part and / or the material of the second part is selected from metals, polymers, compound materials, carbon fiber materials, and ceramic materials. It is also preferred that the method as described herein is a method of manufacturing and recycling of automotive panel assemblies or battery assemblies.

[0051] Yet another aspect of the present disclosure is the use of the heat-initiated debondable article as described herein in the manufacture of recyclable articles. Preferably, the article is selected from panels, vehicle body parts, battery parts, interior parts, exterior parts. It is further preferred that the manufacture takes place in the automotive industry, the commercial transportation industry, the civil engineering industry, the aerospace industry, or the shipbuilding industry. It is particularly preferred that the recyclable article is a part of a battery, and the battery is part of a car, a truck, a train, an aircraft, a spacecraft, a watergoing vessel such as a ship or a boat, a tool, a household applicance or an electricity system or a photovoltaic system of a building.EXEMPLARY EMBODIMENTS

[0052] 1. A heat-initiated debondable attachment article, comprising• a first substrate,• a first debondable coating on the first substrate and having a first major surface immediately adjacent the first substrate and a second major surface, and comprising a first blend of thermoplastic polymers;• a first adhesive layer immediately adjacent the second major surface of the first debondable coating;• optionally a second substrate immediately adjacent the first adhesive layer; wherein the first blend and the second blend of thermoplastic polymers each comprise at least a first thermoplastic polymer and a second thermoplastic polymer, wherein the first thermoplastic polymer and the second thermoplastic polymer of the first blend are independently selected from the first thermoplastic polymer and the second thermoplastic polymer of the second blend, wherein the first adhesive layer comprises a curable adhesive, preferably a 2-part adhesive, wherein the attachment article does not have a porous support layer, wherein the first thermoplastic polymer and the second thermoplastic polymer are each independently chosen from polyesters, wherein the first debondable coating and / or the second debondable coating optionally comprises at least one toughener and / or at least one adhesion promoter.

[0053] 2. A heat-initiated debondable attachment article, comprising• a first substrate,• a first debondable coating on the first substrate and having a first major surface immediately adjacent the first substrate and a second major surface, and comprising a first blend of thermoplastic polymers;• a first adhesive layer immediately adjacent the second major surface of the first debondable coating;• optionally a second substrate immediately adjacent the first adhesive layer; wherein the first blend and the second blend of thermoplastic polymers each comprise at least a first thermoplastic polymer and a second thermoplastic polymer, wherein the first thermoplastic polymer and the second thermoplastic polymer of the first blend are independently selected from the first thermoplastic polymer and the second thermoplastic polymer of the second blend, wherein the first adhesive layer comprises a curable adhesive, preferably a 2-part adhesive, wherein the first thermoplastic polymer and the second thermoplastic polymer are each independently chosen from polyesters, wherein the first debondable coating and / or the second debondable coating optionally comprises at least one toughener and / or at least one adhesion promoter.

[0054] 3. A heat-initiated debondable attachment article, comprising• a first substrate,• a first debondable coating coated on the first substrate and having a first major surface immediately adjacent the first substrate and a second major surface, and comprising a first blend of thermoplastic polymers;• a first adhesive layer immediately adjacent the second major surface of the first debondable coating;• a second substrate immediately adjacent the first adhesive layer;wherein the first blend and the second blend of thermoplastic polymers each comprise at least a first thermoplastic polymer and a second thermoplastic polymer, wherein the first thermoplastic polymer and the second thermoplastic polymer of the first blend are independently selected from the first thermoplastic polymer and the second thermoplastic polymer of the second blend, wherein the first adhesive layer comprises a curable adhesive, preferably a 2-part adhesive, wherein the attachment article does not have a porous support layer, wherein the first thermoplastic polymer and the second thermoplastic polymer are each independently chosen from polyesters, wherein the first debondable coating and / or the second debondable coating optionally comprises at least one toughener and / or at least one adhesion promoter.

[0055] 4. A heat-initiated debondable attachment article, comprising• a first substrate,• a first debondable coating coated on the first substrate and having a first major surface immediately adjacent the first substrate and a second major surface, and comprising a first blend of thermoplastic polymers;• a first adhesive layer immediately adjacent the second major surface of the first debondable coating;• optionally a second substrate immediately adjacent the first adhesive layer; wherein the first blend and the second blend of thermoplastic polymers each comprise at least a first thermoplastic polymer and a second thermoplastic polymer, wherein the first thermoplastic polymer and the second thermoplastic polymer of the first blend are independently selected from the first thermoplastic polymer and the second thermoplastic polymer of the second blend, wherein the first adhesive layer comprises a curable adhesive, preferably a 2-part adhesive, wherein the attachment article does not have a porous support layer, wherein the first thermoplastic polymer and the second thermoplastic polymer are each independently chosen from polyesters, wherein the first thermoplastic polymer has a glass transition temperature from 20°C to 55 °C and the second thermoplastic polymer has a glass transition temperature from greater than 55 °C to 100°C, wherein the first debondable coating and / or the second debondable coating optionally comprises at least one toughener and / or at least one adhesion promoter.

[0056] 5. A heat-initiated debondable attachment article, comprising• a first substrate,• a first debondable coating coated on the first substrate and having a first major surface immediately adjacent the first substrate and a second major surface, and comprising a first blend of thermoplastic polymers;• a first adhesive layer immediately adjacent the second major surface of the first debondable coating;• optionally a second substrate immediately adjacent the first adhesive layer;wherein the first blend and the second blend of thermoplastic polymers each comprise at least a first thermoplastic polymer and a second thermoplastic polymer, wherein the first thermoplastic polymer and the second thermoplastic polymer of the first blend are independently selected from the first thermoplastic polymer and the second thermoplastic polymer of the second blend, wherein the first adhesive layer comprises a curable adhesive, preferably a 2-part adhesive, wherein the attachment article does not have a porous support layer, wherein the first thermoplastic polymer and the second thermoplastic polymer are each independently chosen from polyesters, wherein the first thermoplastic polymer has a glass transition temperature from 20°C to 55 °C and the second thermoplastic polymer has a glass transition temperature from greater than 55 °C to 100°C, and wherein the first debondable coating and / or the second debondable coating optionally comprises at least one toughener and / or at least one adhesion promoter.

[0057] 6. A heat-initiated debondable attachment article, comprising• a first substrate,• a first debondable coating coated on the first substrate and having a first major surface immediately adjacent the first substrate and a second major surface, and comprising a first blend of thermoplastic polymers;• a first adhesive layer immediately adjacent the second major surface of the first debondable coating;• optionally a second substrate immediately adjacent the first adhesive layer; wherein the first blend and the second blend of thermoplastic polymers each comprise at least a first thermoplastic polymer and a second thermoplastic polymer, wherein the first thermoplastic polymer and the second thermoplastic polymer of the first blend are independently selected from the first thermoplastic polymer and the second thermoplastic polymer of the second blend, wherein the first adhesive layer comprises a curable adhesive, preferably a 2-part adhesive, wherein the attachment article does not have a porous support layer, wherein the first thermoplastic polymer and the second thermoplastic polymer are each independently chosen from polyesters, wherein the first thermoplastic polymer has a glass transition temperature from 20°C to 55 °C and the second thermoplastic polymer has a glass transition temperature from greater than 55 °C to 100°C, and wherein the article has an overlap shear strength at a temperature from -40°C to 60 °C higher than 6.5 MPa, for example in the range of from 6.5 to 25 MPa or from 6.5 to 10 MPa and has an overlap shear strength at a temperature from 80 to 100 °C lower than 5 MPa, preferably less than 3 MPa, and more preferably less than 1.5 MPa, wherein the first debondable coating and / or the second debondable coating optionally comprises at least one toughener and / or at least one adhesion promoter.

[0058] 7. A heat-initiated debondable attachment article, comprising• a first substrate,• a first debondable coating coated on the first substrate and having a first major surface immediately adjacent the first substrate and a second major surface, and comprising a first blend of thermoplastic polymers;• a first adhesive layer immediately adjacent the second major surface of the first debondable coating;• optionally a second substrate immediately adjacent the first adhesive layer; wherein the first blend and the second blend of thermoplastic polymers each comprise at least a first thermoplastic polymer and a second thermoplastic polymer, wherein the first thermoplastic polymer and the second thermoplastic polymer of the first blend are independently selected from the first thermoplastic polymer and the second thermoplastic polymer of the second blend, wherein the first adhesive layer comprises a curable adhesive, preferably a 2-part adhesive, wherein the attachment article does not have a porous support layer, wherein the first thermoplastic polymer and the second thermoplastic polymer are each independently chosen from polyesters, wherein the first thermoplastic polymer has a glass transition temperature from 20°C to 55 °C and the second thermoplastic polymer has a glass transition temperature from greater than 55 °C to 100°C, and wherein the article has an overlap shear strength at a temperature from -40°C to 60 °C higher than 6.5 MPa, for example in the range of from 6.5 to 25 MPa or from 6.5 to 10 MPa and has an overlap shear strength at a temperature from 80 to 100 °C lower than 5 MPa, preferably less than 3 MPa, and more preferably less than 1.5 MPa, wherein the article has a Floating Roller Peel at a temperature range between -40°C to 60 °C in the range of from 80 N / 2.5 cm to 250 N / 2.5 cm and has a Floating Roller Peel at a temperature from 80 to 100 °C less than 55 N / 2.5 cm, preferably less than 50 N / 2.5 cm, and more preferably less than 45 N / 2.5 cm and even more preferably less than 35 N / 2.5 cm at a temperature in the range of from 80 to 100 °C, wherein the first debondable coating and / or the second debondable coating optionally comprises at least one toughener and / or at least one adhesion promoter.

[0059] 8. A heat-initiated debondable attachment article, comprising• a first substrate,• a first debondable coating coated on the first substrate and having a first major surface immediately adjacent the first substrate and a second major surface, and comprising a first blend of thermoplastic polymers;• a first adhesive layer immediately adjacent the second major surface of the first debondable coating;• optionally a second substrate immediately adjacent the first adhesive layer;wherein the first blend and the second blend of thermoplastic polymers each comprise at least a first thermoplastic polymer and a second thermoplastic polymer, wherein the first thermoplastic polymer and the second thermoplastic polymer of the first blend are independently selected from the first thermoplastic polymer and the second thermoplastic polymer of the second blend, wherein the first adhesive layer comprises a curable adhesive, preferably a 2-part adhesive, wherein the attachment article does not have a porous support layer, wherein the first thermoplastic polymer and the second thermoplastic polymer are each independently chosen from polyesters, wherein the first thermoplastic polymer has a glass transition temperature from 20°C to 55 °C and the second thermoplastic polymer has a glass transition temperature from greater than 55 °C to 100°C, and wherein the article has a Floating Roller Peel at a temperature range between -40°C to 60 °C in the range of from 80 N / 2.5 cm to 250 N / 2.5 cm and has a Floating Roller Peel at a temperature from 80 to 100 °C less than 55 N / 2.5 cm, preferably less than 50 N / 2.5 cm, and more preferably less than 45 N / 2.5 cm and even more preferably less than 35 N / 2.5 cm at a temperature in the range of from 80 to 100 °C, wherein the first debondable coating and / or the second debondable coating optionally comprises at least one toughener and / or at least one adhesion promoter.

[0060] 9. A heat-initiated debondable attachment article, comprising• a first substrate,• a first debondable coating coated on the first substrate and having a first major surface immediately adjacent the first substrate and a second major surface, and comprising a first blend of thermoplastic polymers;• a first adhesive layer immediately adjacent the second major surface of the first debondable coating;• optionally a second substrate immediately adjacent the first adhesive layer; wherein the first blend and the second blend of thermoplastic polymers each comprise at least a first thermoplastic polymer and a second thermoplastic polymer, wherein the first thermoplastic polymer and the second thermoplastic polymer of the first blend are independently selected from the first thermoplastic polymer and the second thermoplastic polymer of the second blend, wherein the first adhesive layer comprises a curable adhesive, preferably a 2-part adhesive, wherein the attachment article does not have a porous support layer, wherein the first thermoplastic polymer and the second thermoplastic polymer are each independently chosen from polyesters, wherein the first debondable coating and / or the second debondable coating optionally comprises at least one toughener and / or at least one adhesion promoter,wherein the thickness of the first debondable coating and the thickness of the optional second debondable coating are each, independently from each other, from 1 micron to 25 microns, in other embodiments from 1 to 15 microns, and other embodiments from 1 micron to 10 microns.

[0061] 10. A heat-initiated debondable attachment article, comprising• a first substrate,• a first debondable coating coated on the first substrate and having a first major surface immediately adjacent the first substrate and a second major surface, and comprising a first blend of thermoplastic polymers;• a first adhesive layer immediately adjacent the second major surface of the first debondable coating;• optionally a second substrate immediately adjacent the first adhesive layer; wherein the first blend and the second blend of thermoplastic polymers each comprise at least a first thermoplastic polymer and a second thermoplastic polymer, wherein the first thermoplastic polymer and the second thermoplastic polymer of the first blend are independently selected from the first thermoplastic polymer and the second thermoplastic polymer of the second blend, wherein the first adhesive layer comprises a curable adhesive, preferably a 2-part adhesive, wherein the attachment article does not have a porous support layer, wherein the first thermoplastic polymer and the second thermoplastic polymer are each independently chosen from polyesters, wherein the first debondable coating and / or the second debondable coating optionally comprises at least one toughener, wherein the at least first and second thermoplastic polymers each independently of each other have a molecular weight greater than 5,000g / mol, preferably from 5,000 g / mol to 50,000 g / mol, preferably from 7,000 to 40,000 g / mol, and more preferably from 8,000 to 30,000 g / mol, even more preferably from 10,000 g / mol to 20,000 g / mol.

[0062] 11. A heat-initiated debondable attachment article, comprising• a first substrate,• a first debondable coating coated on the first substrate and having a first major surface immediately adjacent the first substrate and a second major surface, and comprising a first blend of thermoplastic polymers;• a first adhesive layer immediately adjacent the second major surface of the first debondable coating;• optionally a second substrate immediately adjacent the first adhesive layer; wherein the first blend and the second blend of thermoplastic polymers each comprise at least a first thermoplastic polymer and a second thermoplastic polymer, wherein the first thermoplastic polymer and the second thermoplastic polymer of the first blend are independently selected from the first thermoplastic polymer and the second thermoplastic polymer of the second blend, wherein the first adhesive layer comprises a curable adhesive, preferably a 2-part adhesive,wherein the attachment article does not have a porous support layer, wherein the first thermoplastic polymer and the second thermoplastic polymer are each independently chosen from polyesters, wherein the first debondable coating and / or the second debondable coating optionally comprises at least one toughener wherein the at least first thermoplastic polymer has a molecular weight from 5,000 g / mol to13,000 g / mol, preferably from 7,000 to 13,000 g / mol, and more preferably from 8,000 to13,000 g / mol, even more preferably from 10,000 g / mol to 13,000 g / mol, wherein the at least second thermoplastic polymer has a molecular weight from 13,500 g / mol to 50,000 g / mol, preferably from 13,500 to 40,000 g / mol, and more preferably from 13,500 to 30,000 g / mol, even more preferably from 14,000 g / mol to 20,000 g / mol.

[0063] 12. The heat-initiated debondable attachment article according to any of the preceding embodiments, wherein the first thermoplastic polymer in the blend of thermoplastic polymers has a glass transition temperature from 20°C to 55 °C and the second thermoplastic polymer has a glass transition temperature from greater than 55°C to 100°C.

[0064] 13. The heat-initiated debondable attachment article according to any of the preceding embodiments, wherein the article has an overlap shear strength at a temperature from -40°C to 60 °C higher than 6.5 MPa, for example in the range of from 6.5 to 25 MPa or from 6.5 to 10 MPa and has an overlap shear strength at a temperature from 80 to 100 °C lower than 5 MPa, preferably less than 3 MPa, and more preferably less than 1.5 MPa.

[0065] 14. The heat-initiated debondable attachment article according to any of the preceding embodiments, wherein the thickness of the first debondable coating and the thickness of the optional second debondable coating are each, independently from each other, greater than 1 micron or greater than 5 microns.

[0066] 15. The heat-initiated debondable attachment article according to any of the preceding embodiments, wherein the thickness of the first debondable coating and the thickness of the optional second debondable coating are each, independently from each other, from 1 micron to 30 microns or from 5 to 30 microns.

[0067] 16. The heat-initiated debondable attachment article according to any of the preceding embodiments, wherein the thickness of the first debondable coating and the thickness of the optional second debondable coating are each, independently from each other, from 1 micron to 20 microns or from 5 to 20 microns.

[0068] 17. The heat-initiated debondable attachment article according to any of the preceding embodiments, wherein the thickness of the first debondable coating and the thickness of the optional second debondable coating are each, independently from each other, from 1 micron to 10 microns or from 5 to 10 microns.

[0069] 18. The heat-initiated debondable attachment article according to any of the preceding embodiments, wherein the thickness of the first debondable coating and the thickness of the optional seconddebondable coating are each, independently from each other, from 1 micron to 25 microns, in other embodiments from 1 to 15 microns, and other embodiments from 1 micron to 10 microns.

[0070] 19. The heat-initiated debondable attachment article according to any of the preceding embodiments, wherein the article has a Floating Roller Peel at a temperature range between -40°C to 60 °C in the range of from 80 N / 2.5 cm to 250 N / 2.5 cm and has a Floating Roller Peel at a temperature from 80 to 100 °C less than 55 N / 2.5 cm, preferably less than 50 N / 2.5 cm, and more preferably less than 45 N / 2.5 cm and even more preferably less than 35 N / 2.5 cm at a temperature in the range of from 80 to 100 °C.

[0071] 20. The heat-initiated debondable attachment article according to any one of the preceding embodiments, wherein the blend of at least a first and a second thermoplastic polymers exhibits a glass transition temperature in the range of from 60 to 120 °C, preferably from 65 to 100 °C, and more preferably from 80 to 100 °C.

[0072] 21. The heat-initiated debondable attachment article according to any one of the preceding embodiments, wherein the at least first and second thermoplastic polymers is each independently selected from polyesters, poly(meth)acrylates, acrylonitrile butadiene styrenes, polyamides, polybenzimidazoles, polycarbonates, polyether sulfones, polyoxymethylenes, polyether ether ketones, polyetherimides, polyethylenes, polyphenylene oxides, polyphenylene sulfides, polypropylenes, polystyrenes, polyvinyl chlorides, and any combinations thereof, preferably polyesters.

[0073] 22. The heat-initiated debondable attachment article according to any one of the preceding embodiments, wherein the at least first and second thermoplastic polymers each independently of each other have a molecular weight greater than 5,000g / mol, preferably from 5,000 g / mol to 50,000 g / mol, preferably from 7,000 to 40,000 g / mol, and more preferably from 8,000 to 30,000 g / mol, even more preferably from 10,000 g / mol to 20,000 g / mol.

[0074] 23. The heat-initiated debondable attachment article according to any one of the preceding embodiments, wherein the at least first thermoplastic polymer has a molecular weight from 5,000 g / mol to 15,000 g / mol, preferably from 7,000 to 15,000 g / mol, and more preferably from 8,000 to 15,000 g / mol, even more preferably from 10,000 g / mol to 15,000 g / mol.

[0075] 24. The heat-initiated debondable attachment article according to any one of the preceding embodiments, wherein the at least second thermoplastic polymer has a molecular weight from 15,500 g / mol to 50,000 g / mol, preferably from 15,500 to 40,000 g / mol, and more preferably from 15,500 to 30,000 g / mol, even more preferably from 15,500 g / mol to 20,000 g / mol.

[0076] 25. The heat-initiated debondable attachment article according to any one of the preceding embodiments, wherein the at least first thermoplastic polymer has a molecular weight from 5,000 g / mol to 15,000 g / mol, preferably from 7,000 to 15,000 g / mol, and more preferably from 8,000 to 15,000 g / mol, even more preferably from 10,000 g / mol to 15,000 g / mol and wherein the at least second thermoplastic polymer has a molecular weight from 15,500 g / mol to 50,000 g / mol, preferably from 15,500 to 40,000 g / mol, and more preferably from 15,500 to 30,000 g / mol, even more preferably from 15,500 g / mol to 20,000 g / mol.

[0077] 26. The heat-initiated debondable attachment article according to any of the preceding embodiments, wherein the first debondable coating and / or the second debondable coating comprises at least one toughener, and wherein the at least one toughener is selected independently for each coating from butadiene rubbers, nitrile rubbers, and core-shell rubbers, more preferably from core-shell rubbers.

[0078] 27. The heat-initiated debondable attachment article according to any of the preceding embodiments, wherein the first debondable coating and / or the second debondable coating comprises at least one adhesion promoter, and wherein the at least one adhesion promoter is selected independently for each coating from polyisocyanates, silanes, polyesters, tackifiers (e.g. rosins and their derivatives, terpenes and modified terpenes aliphatic, cycloaliphatic and aromatic resins (C5 aliphatic resins, C9 aromatic resins, and C5 / C9 aliphatic / aromatic resins), hydrogenated hydrocarbon resins, and their mixtures, terpene -phenol resins (TPR, used often with ethylene -vinyl acetate adhesives)), novolacs, and combinations thereof.

[0079] 28. The heat-initiated debondable attachment article according to any one of the preceding embodiments, wherein the article comprises perforations.

[0080] 29. A die-cut, comprising the article according to any one of the preceding embodiments.

[0081] 30. A part assembly comprising a first part and a second part, and the heat-initiated debondable attachment article according to any one of embodiments 1 to [,0ft79]^ wherein the first substrate and the second substrate correspond to the first and the second parts respectively.

[0082] 31. A method for bonding a part assembly, the method comprising the following steps:• applying a first debondable coating as recited in any one of embodimentsonto at least part of a surface of a first part;• applying a first adhesive layer to either a portion of a surface of a second part or a surface of the first debondable coating coating;• Attaching the second part to the first part such that the first debondable coating and the first adhesive layer connect the first part to the second part, thereby forming a part assembly;• allowing the at least one first adhesive to cure.

[0083] 32. A method for debonding a part assembly, the method comprising the following steps:• providing a part assembly comprising a first part bonded to a second part, and further comprising at least a first debondable coating,• heating the part assembly so as to soften and / or at least partially melt the first debondable coating and / or second debondable coating;• disconnecting the second part from the first part.

[0084] 33. A method for debonding a part assembly according to embodiment [0QS3J32, wherein the disconnecting step is carried out by a method chosen from applying prying forces, floating roller peel forces (peel forces in general) and tensile forces and combinations thereof.

[0085] 34. A recyclable article comprising a heat-initiated debondable attachment article according to any one of embodiments 1 to .[ 0? k or the die-cut according to embodiment s0980]29.

[0086] 35. A coating solution consisting of, preferably consisting essentially of, a coating composition, wherein the coating composition consists, preferably consists essentially of:a. a first thermoplastic polymer having a glass transition temperature from 20°C to 55 °C, b. a second thermoplastic polymer having a glass transition temperature from greater than 55 °C to 100°C, c. a toughener, d. an adhesion promoter, and e. a solvent. f. Additives (e.g UV dye)

[0087] 36. A coating solution consisting of, preferably consisting essentially of a coating composition, wherein the coating composition consists, preferably consists essentially of: a. a first thermoplastic polymer having a glass transition temperature from 20°C to 55 °C, wherein the first thermoplastic polymer has a molecular weight from 5,000 g / mol to 13,000 g / mol, preferably from 7,000 to 13,000 g / mol, and more preferably from 8,000 to 13,000 g / mol, even more preferably from 10,000 g / mol to 13,000 g / mol, b. a second thermoplastic polymer having a glass transition temperature from greater than 55 °C to 100°C, wherein the second thermoplastic polymer has a molecular weight from 13,500 g / mol to 50,000 g / mol, preferably from 13,500 to 40,000 g / mol, and more preferably from 13,500 to 30,000 g / mol, even more preferably from 14,000 g / mol to 20,000 g / mol, c. an adhesion promoter chosen from polyisocyanates, silanes, polyesters, and tackifiers d. a toughener, wherein the toughener is chosen from Core Shell Rubbers and Polyvinylbutyral, e. optionally a UV indicator, f. optionally a hydrolysis stabilizer, and g. a solvent, preferably methylethylketone and / or dimethyl carbonate.

[0088] 37. A coating solution according to any preceding embodiments directed to coating solutions, wherein: a. the first thermoplastic polymer is present in a concentration from 1.0wt%- 15 wt%. b. the second thermoplastic polymer is present in a concentration from 1.0 - 15 wt%, c. the adhesion promoter is present in a concentration from 0.0 wt% - 8 wt%, d. the toughener is present in a concentration from 0.0 - 8 wt%, e. the UV indicator is present in a concentration from 0 to 1.0wt%, if present is preferably in a concentration of 0.05 to 0.5% f. the hydrolysis stabilizer is present in a concentration from 0 to 1.0wt%, if present is preferably in a concentration of 0.05 to 0.5%and g. the solvent is present in a concentration from 70 - 90 wt% and is chosen from MEK, acetone, 1 -propanol, 2-propanol, 1 -butanol, 2-propanol, t-butanol, propyl acetate, ethyl acetate isopropanol, ethanol, green solvents (e.g., d-limonene, dimethyl carbonate, dibasic esters,) and combinations thereof.

[0089] 38. A coating solution according to any preceding embodiments directed to coating solutions, wherein:a. the first thermoplastic polymer is present in a concentration from 5.0 - 15 wt% b. the second thermoplastic polymer is present in a concentration from 5.0 - 15 wt% c. the adhesion promoter is present in a concentration from 2.0 - 8 wt% d. the toughener is present in a concentration from 2.0 - 8 wt% e. the solvent is present in a concentration from 80 - 90 wt% and is chosen from MEK, d- limonene, dimethyl carbonate, and dibasic esters.

[0090] 39. A kit comprising: g. a primer solution according to any preceding embodiments directed to primer solutions, and h. an adhesive.

[0091] 40. A kit according to any of the preceding embodiments directed to kits, wherein the adhesive is either a structural adhesive or a semi-structural adhesive.EXAMPLES

[0092] The present disclosure is further described without however wanting to limit the disclosure thereto. The following examples are provided to illustrate certain embodiments but are not meant to be limited in any way. All parts and percentages are by weight unless otherwise indicated. The used test methods are described in the respective Example sections. After each Example section the results are evaluated.Used Materials

[0093] Table 1: Used materials, their descriptions and suppliers1Molecular weight / Mn: Calculated based on the final hydroxyl number and acid number contained; Hydroxyl value / OH value: Refer to DIN 53 240-02. Magnesium hydroxide equivalent to the hydroxyl content per gram of sample, in mg KOH / g. The acid value of the solution product was measured as 100% solids resin; Acid value: Refer to DIN EN ISO 2114. The amount of potassium hydroxide needed to neutralize the acidic substance in 1g sample, in mg KOH7g. The acid value of the solution product was measured as 100% solids resin; Glass transition temperature (Tg): Refer to DIN 53 765. The glass transition temperature refers to the transition temperature from the glassy state to the highly elastic state or from the latter to the amorphous state of the amorphous polymer (including the amorphous portion in the crystalline polymer). Using a differential scanning calorimeter (DSC), the temperature increase rate was 10°C / min. Density: Refer to DIN 51 757. (refer to Macroocean Product Catalogue Copolyester Product Line).

[0094] To manufacture the heat initiated debondable coatings 1 - 3, the selected ingredients were added to a coating can and dissolved in the given solvent overnight at ambient temperature under stirring (table 1).

[0095] Table 2: Heat-Initiated Debondable Coating Formulation.Test Methods

[0096] The used test methods are described in detail in the relevant Example sections.Example Section 1 - Sandblasted Aluminum / Aluminum - General TestingTest MethodsOverlap Shear Strength (OLS)

[0097] Overlap Shear Strength was determined according to DIN EN 1465 (issued 2009). Panels of 2024-T3 bare aluminum measuring 10 x 2.5 x 1.6 cm were used. All specimens were sandblasted until a uniform matte appearance was achieved. The loose grit residue was removed using Methylethylketone (MEK) in combination with a lint-free cloth. Bond area was 12.5 x 25 mm in all cases. Bondline thickness was adjusted by adding glass beads of 90-150 microns in diameter to the used adhesive or by using PTFE shims of 1mm.

[0098] Coatings 1 and 2 were applied to the first panel of the assembly by means of a clean lint-free cloth (Example 1 and 2). The coated parts were allowed to dry under ambient conditions for 60 minutes to form a thin film.

[0099] DP 8910 was applied to the first and second panel of the assembly of Example 1 and Comparative Example 1. In case of Example 2 the second panel of the assembly- and in case of Comparative Example 2 both panels of the assembly were primed with 3M 86A according to the technical instructions before DP6330 was applied. All specimens were fixed by means of clamps and allowed to cure for 24 hours at ambient temperature (Example 1, Comparative Example 1) or 7d at ambient temperature (Example 2, Comparative Example 2). Excesses of cured adhesive at the edges of the specimens were removed by means of sandpaper. Two samples were tested per group and the average value, incl. standard deviation (in MPa) was reported. The test was conducted at a rate of 5 mm / minute at -40°C, RT, 60°C and 100°C.Floating Roller Peel (FRP) Strength Test

[0100] The methods of EN2243-2 2006 were followed. Panels of 2024-T3 bare aluminum measuring 25 x 2.5 x 0.16 cm (thick) and 25 x 2.5 x 0.05 cm (thin) were used. All specimens were sandblasted until a uniform matte appearance has been achieved. The loose grit residue was removed using Methylethylketone (MEK) in combination with a lint-free cloth. Bond area was 200 x 25 mm in all cases. Bondline thickness was adjusted by adding glass beads of 90-150 microns in diameter to the used adhesive.Coating 1 and 2 were applied to the thick panel of the assembly by means of a clean lint-free cloth (Example 1 and 2). The coated parts were allowed to dry under ambient conditions for 60 minutes to form a thin film.

[0101] DP 8910 was applied to the thin and thick panel of the assembly of Example 1 and Comparative Example 1. In case of Example 2 the thin panel of the assembly- and in case of Comparative Example 2 both panels of the assembly were primed with 3M 86A according to the technical instructions before DP6330 was applied. All specimens were fixed by means of clamps and allowed to cure for 24 hours atambient temperature (Example 1, Comparative Example 1) or 7d at ambient temperature (Example 2, Comparative Example 2). Excesses of cured adhesive at the edges of the specimens were removed by means of sandpaper. Two samples were tested per group and the average value, incl. standard deviation (in N / 25 mm) was reported. The test was conducted at a rate of 140 mm / minute at ambient temperature and 100°C according to the workflow described in the repair section. In each test, the thinner substrate was peeled from the thicker one, and the results normalized to a width of 25 mm.

[0102] Table 3 : Lap Shear strengths / Floating Roller Peel for coating 1 and 2 of the invention tested on sandblasted Aluminum / Aluminum substrates.MF: Mixed failure mode; CF: Cohesive Failure, AF: Adhesion Failure of adhesive (refer to Example section 5)Evaluation

[0103] As can be seen in Table 3 Coating 1 shows comparable strength to Comparative Example 1 for Overlap Shear strength from -40 - 60°C and a desired significant drop at 100°C of 55% [difference between Example 1 and Comparative Example 1 at 100°C, calculated via e.g.: %Drop = ((7.6 MPa - 3.4 MPa) / 7.6 MPa)* 100]) (90-150 pm bondline Thickness) and 31% (1000 pm bondline thickness). For Floating RollerPeel a drop in strength of 86% was observed at 100°C. Additionally, no adhesive residuals were observed on the first panel of the assembly (OLS) and thick panel (FRP) after testing at 100°C (refer to Example Section 2). Coating 2 shows also comparable strength for OLS against Comparative Example 2 and a significant drop for FRP of 60% at 100°C again with no adhesive residuals on the coated first panel of the assembly. In conclusion, the results show that Coatings 1 and 2 are suitable as debondable coatings.Example Section 2 - Repairability

[0104] In order to show the repair properties of Coating 1, the testing was conducted according to the workflow given in FIG. 2. The repair properties were proven based on Overlap Shear Strength- and Floating Roller Peel testing. Five groups with two specimens each (n=2; e.g. 1.0.a & 1.0.b a 1.0) were manufactured. Group 1.0 was tested at room temperature and can be regarded as reference. Groups 2.0 - 5.0 were debonded at 100°C. Results of the first heat initiated debonding step can be regarded as benchmark for later debonding results. After first repair cycle group 2.1 (made out of group 2.0) was tested at ambient temperature and group 3.1 (made out of group 3.0) was tested at 100°C. Furthermore, groups 4.1 and 5.1 were tested at 100°C. After second repair cycle group 4.2 (made out of group 4.1) was tested at ambient temperature and group 5.2 (made out of group 5.1) was tested at 100°C.Test MethodsOverlap Shear Strength

[0105] The initial specimen manufacturing was conducted according to the described process in Example section 1 following workflow for Example 1 and Comparative Example 1 (Bondline thickness 90 - 150 microns). The test was conducted at a rate of 5 mm / minute at ambient temperature and 100°C according to the workflow described in FIG. 1. Repair Protocol: After debonding at 100°C, the coated panel (1stpanel of the assembly) was cleaned with MEK using a lint-free cloth. Subsequently, Coating 1 was again applied onto the same surface. A new 2ndpanel of the assembly was sandblasted and cleaned according to the procedure described above followed by assembling, curing of the adhesive and testing (refer to Example section 1).Floating Roller Peel (FRP) Strength Test

[0106] The initial specimen manufacturing was conducted according to the described process in Example section 1 following workflow for Example 1 and Comparative Example 1 (Bondline thickness 90 - 150 microns). The test was conducted at a rate of 140 mm / minute at ambient temperature and 100°C according to the workflow described in FIG. 1. In each test, the thinner substrate was peeled from the thicker one, and the results normalized to a width of 25 mm. Repair Protocol: After debonding at 100°C, the coated panel (thick) was cleaned with MEK using a lint-free cloth. Subsequently, Coating 1 was again applied onto the same surface. A new panel measuring 25 x 2.5 x 0.05 cm (thin) was sandblasted and cleaned according to the procedure described above followed by assembling, curing of the adhesive and testing (refer to Example section 3).

[0107] In order to show the repair properties of the invention, the testing was conducted according to the descriptions of Example section 2. Beside the mechanical results the obtained failure modes were evaluated. The results are summarized in table 4.

[0108] Table 4: Repairability of Lap Shear strengths / Floating Roller Peel specimens for Coating 1 of the invention tested on sandblasted Aluminium / Aluminium substrates.MF: Mixed failure mode; CF: Cohesive Failure, AF: Adhesion Failure of adhesive (refer to Example section 5).Evaluation:

[0109] As can be seen in table 4 Example 1 showed an initial Overlap Shear Strength of 18.2 MPa with a mixed failure mode (90% cohesive, 10% adhesive) (Group# 1.0). Comparative Example 1 showed 18.7 MPa. Groups# 2.0 - 5.0 were debonded at 100°C showing a favourable adhesive failure mode on the coatedpart of the panel (no residual of adhesive on substrate). Comparative Example 1 showed 7.6 MPa with cohesive failure tested at 100°C. No repair is possible in this case. After first repair cycle (see procedure above) group# 2.1 again reached comparable values to Group# 1. Groups# 3.1 - 5.1 again showed good debondability at 100°C resulting in comparable results to Groups# 2.0 - 5.0. After second repair cycle group 4.2 again reached comparable values to Group# 2.1 and 1.0. Group 5.0 again showed good debondability at 100°C resulting in comparable results to Groups# 2.0 - 5.0 and 3.1 - 5.1. The same positive results were found for Floating Roller Peel testing. Example 1 showed an initial Floating Roller Peel Strength of 141 N / 2.5 cm with a cohesive failure mode (Group# 1.0). Comparative Example 1 showed 175 N / 2.5 cm in average. Groups# 2.0 - 5.0 were debonded at 100°C showing a favourable adhesive failure mode on the coated part of the panel measuring 25 x 2.5 x 0.16 cm (no residual of adhesive on substrate). Comparative Example 1 showed 216 N / 2.5 cm with cohesive failure tested at 100°C. No repair is possible in this case. After first repair cycle (see procedure above) group# 2.1 again reached comparable values to Group# 1. Groups# 3.1 - 5.1 again showed good debondability at 100°C resulting in comparable results to Groups# 2.0 - 5.0. After second repair cycle group 4.2 again reached comparable values to Group# 2. 1 and 1.0. Group 5.0 again showed good debondability at 100°C resulting in comparable results to Groups# 2.0 - 5.0 and 3.1 - 5.1. In conclusion, the disclosed results showed that Coating 1 allows at least two repair cycles of a given assembly based on Overlap Shear Strength- and Floating Roller Peel testing.Example Section 3 - Environmental Cycle Test (According to PV-1200)Overlap Shear Strength

[0110] Overlap Shear Strength was determined according to DIN EN 1465 (issued 2009). Panels of 2024-T3 bare aluminum measuring 10 x 2.5 x 1.6 cm were used. All specimens were sandblasted until a uniform matte appearance was achieved. The loose grit residue was removed using Methylethylketone (MEK) in combination with a lint-free cloth. Bond area was 12.5 x 25 mm in all cases. Bondline thickness was adjusted by adding glass beads of 90-150 microns in diameter to the used adhesive.Coating 3 was applied to the first panel of the assembly by means of a clean lint-free cloth (Example 4 and 6). The coated parts were allowed to dry under ambient conditions for 60 minutes to form a thin film. DP 8910 was applied to the first and second panel of the assembly of Example 4 and Comparative Example 1. In case of Example 5 the second panel of the assembly- and in case of Comparative Example 2 both panels of the assembly were primed with 3M 86A according to the technical instructions before DP6330 was applied. All specimens were fixed by means of clamps and allowed to cure for 24 hours at ambient temperature (Example 4, Comparative Example 1) or 7d at ambient temperature (Example 5, Comparative Example 2). Excesses of cured adhesive at the edges of the specimens were removed by means of sandpaper. Three samples were tested per group initially and the average value, incl. standard deviation (in MPa) was reported. The test was conducted at a rate of 5 mm / minute at RT. Three samples of each group were put into a climate oven for 50 days following the below described environmental cycle test (50 days, 100 cycles). After 100 cycles all specimens were placed into a room with standard temperature and humidity (23 °C, 50 % RH) for 24h before testing at a rate of 5 mm / minute at RT.

[0111] A 12 hour cycle (720 mins) o Step 1 - 1 hour (60 min) heating phase to +80 °C and 80% rel. humidity, o Step 2 - 4 hours (240 min) holding time at +80 °C and 80% rel. humidity o Step 3 - 2 hours (120 min) cooling phase to -40 °C, when freezing point is reached: approx. 30% rel. humidity, the air humidity remains unregulated as of T < 0 °C (depending on the system, humidity regulation can also be suspended as of T < 10 °C) o Step 4 - 4 hour (240 min) holding time at -40 °C, air humidity remains uncontrolled o Step 5 - 1 hour (60 min) heating phase to +23 °C, rel. humidity is regulated to 30% as of T = 0°CThe tolerances around the set values are as follows: o Temperature Tolerance ± 2°C o Relative Humidity ± 5%

[0112] Table 5: Lap Shear strengths specimens for Coating 3 of the invention before and after environmental Cycle Test (PV-1200) tested on sandblasted Aluminum / Aluminum substrates.Evaluation

[0113] As can be seen in table 5 Coating 3 (Example 4 and 5) showed comparable initial results for OLS. After 100 cycles of environmental cycle test Example 4 and 5 still showed comparable results to Comparative Example 1 and 2, which were provided to show the strength of the bond without debondable layers. In conclusion, assemblies made using the coatings of this disclosure bond the two substrates as well as traditional structural adhesives without debondable coating.Example Section 4 - Coating Thickness Evaluation (Gravimetric Determination)

[0114] The coating thickness was evaluated by gravimetric measurement. Therefore, Coating 2 was applied to a panel measuring 10.5 x 4.8 cm by means of a lint free cloth (n = 2). The specimens where weight before the coating was applied and 60 minutes after application of the coating. The primer thickness was calculated based on formula 1 and results are shown in table 6. The density of Coating 2 was approximately calculated by means of formula 2 (Density: ca. 1.185 g / ml). To evaluate the maximum thickness of Coating 2, Coating 2 was applied a second and third time on the specimens after the coating was dried.(1) T = (m * 10) / (A * D)T = Coating thickness in pm m = mass of the coating in mg A = surface area in cm2D = Density of coating(2) Dmix (DAH441 [1.2 g / ml] + DAH645 [1.17 g / ml]) / 2

[0115] Table 6: Results of Coating Thickness Evaluation.Evaluation

[0116] As can be seen in table 6 even after three times of wiping coating 2 onto the surface, the coating thickness will be < 25 pm.Example Section 5 - Evaluation of Floating Roller Peel (FRP) Specimen after Heat Initiated Debond by means of UV light

[0117] In order to evaluate the split / failure mode of the coating after heat initiated debond at 100°C, a floating roller peel specimen was manufactured following the process according to Example 1, but using Coating 2 which comprises MPI Bright 100. The coated panel (1stpanel of the assembly) was irradiated by means of UV light (266 nm) to visualize the applied coating (FIG. 3a). FIG. 3a shows the coating in blue color under a UV light due to the presence of the UV dye. After heat initiated debond at 100°C (28 ± 3 N / 2.5 cm) no residual of adhesive (DP8910) was found on the first panel of the assembly (FIG. 3b). FIG.3b shows no adhesive residue on the panel on which the debondable coating was applied. After irradiation by means of UV light (266 nm) it was found that UV dye was detected both on the first panel of the assembly and also on the surface of the adhesive which is fully attached to the second panel of the assembly (FIG. 3c). FIG. 3c shows the surfaces of both panels at which debonding occurred in blue color under UV light. This result clearly indicated that the used coating 2 undergoes a cohesive failure that is not further specified in this disclosure . The use of a UV dye in the coatings of this disclosure, as demonstrate in Coating 2, is preferable to ensure high quality during potential debonding and repair processes.

Claims

We Claim:

1. A heat-initiated debondable attachment article, comprising• a first substrate,• a first debondable coating on the first substrate and having a first major surface immediately adjacent the first substrate and a second major surface, and comprising a first blend of thermoplastic polymers;• a first adhesive layer immediately adjacent the second major surface of the first debondable coating;• optionally a second substrate immediately adjacent the first adhesive layer; wherein the first blend and the second blend of thermoplastic polymers each comprise at least a first thermoplastic polymer and a second thermoplastic polymer, wherein the first thermoplastic polymer and the second thermoplastic polymer of the first blend are independently selected from the first thermoplastic polymer and the second thermoplastic polymer of the second blend, wherein the first adhesive layer comprises a curable adhesive, preferably a 2-part adhesive, wherein the attachment article does not have a porous support layer, wherein the first thermoplastic polymer and the second thermoplastic polymer are each independently chosen from polyesters, wherein the first debondable coating and / or the second debondable coating optionally comprises at least one toughener and / or at least one adhesion promoter.

2. The heat-initiated debondable attachment article according to any of the preceding claims, wherein the article has an overlap shear strength at a temperature from -40°C to 60 °C higher than 6.5 MPa, for example in the range of from 6.5 to 25 MPa or from 6.5 to 10 MPa and has an overlap shear strength at a temperature from 80 to 100 °C lower than 5 MPa, preferably less than 3 MPa, and more preferably less than 1.5 MPa.

3. The heat-initiated debondable attachment article according to any of the preceding claims, wherein the thickness of the first debondable coating and the thickness of the optional second debondable coating are each, independently from each other, from 1 micron to 20 microns or from 5 to 20 microns.

4. The heat-initiated debondable attachment article according to any of the preceding claims, wherein the thickness of the first debondable coating and the thickness of the optional second debondable coating are each, independently from each other, from 1 micron to 25 microns, from 1 to 15 microns, and from 1 micron to 10 microns.

5. The heat-initiated debondable attachment article according to any of the preceding claims, wherein the article has a Floating Roller Peel at a temperature range between -40°C to 60 °C in the range of from 80 N / 2.5 cm to 250 N / 2.5 cm and has a Floating Roller Peel at a temperature from 80 to 100 °C less than 55 N / 2.5 cm, preferably less than 50 N / 2.5 cm, and more preferably less than 45 N / 2.5 cm and even more preferably less than 35 N / 2.5 cm at a temperature in the range of from 80 to 100 °C.

6. The heat-initiated debondable attachment article according to any one of the preceding claims, wherein the blend of at least a first and a second thermoplastic polymers exhibits a glass transition temperature in the range of from 60 to 120 °C, preferably from 65 to 100 °C, and more preferably from 80 to 100 °C.

7. The heat-initiated debondable attachment article according to any one of the preceding claims, wherein the at least first and second thermoplastic polymers is each independently selected from polyesters, poly(meth)acrylates, acrylonitrile butadiene styrenes, polyamides, polybenzimidazoles, polycarbonates, polyether sulfones, polyoxymethylenes, polyether ether ketones, polyetherimides, polyethylenes, polyphenylene oxides, polyphenylene sulfides, polypropylenes, polystyrenes, polyvinyl chlorides, and any combinations thereof, preferably polyesters.

8. The heat-initiated debondable attachment article according to any one of the preceding claims, wherein the at least first and second thermoplastic polymers each independently of each other have a molecular weight greater than 5,000g / mol, preferably from 5,000 g / mol to 50,000 g / mol, preferably from 7,000 to 40,000 g / mol, and more preferably from 8,000 to 30,000 g / mol, even more preferably from 10,000 g / mol to 20,000 g / mol.

9. The heat-initiated debondable attachment article according to any one of the preceding claims, wherein the at least first thermoplastic polymer has a molecular weight from 5,000 g / mol to 15,000 g / mol, preferably from 7,000 to 15,000 g / mol, and more preferably from 8,000 to 15,000 g / mol, even more preferably from 10,000 g / mol to 15,000 g / mol.

10. The heat-initiated debondable attachment article according to any one of the preceding claims, wherein the at least second thermoplastic polymer has a molecular weight from 15,500 g / mol to 50,000 g / mol, preferably from 15,500 to 40,000 g / mol, and more preferably from 15,500 to 30,000 g / mol, even more preferably from 15,500 g / mol to 20,000 g / mol.

11. The heat-initiated debondable attachment article according to any one of the preceding claims, wherein the at least first thermoplastic polymer has a molecular weight from 5,000 g / mol to15,000 g / mol, preferably from 7,000 to 15,000 g / mol, and more preferably from 8,000 to 15,000 g / mol, even more preferably from 10,000 g / mol to 15,000 g / mol and wherein the at least second thermoplastic polymer has a molecular weight from 15,500 g / mol to 50,000 g / mol, preferably from 15,500 to 40,000 g / mol, and more preferably from 15,500 to 30,000 g / mol, even more preferably from 15,500 g / mol to 20,000 g / mol.

12. The heat-initiated debondable attachment article according to any of the preceding claims, wherein the first debondable coating and / or the second debondable coating comprises at least one toughener, and wherein the at least one toughener is selected independently for each coating from butadiene rubbers, nitrile rubbers, and core-shell rubbers, more preferably from core-shell rubbers.

13. A method for debonding a part assembly according to claim 0083133-. wherein the disconnecting step is carried out by a method chosen from applying prying forces, floating roller peel forces (peel forces in general) and tensile forces and combinations thereof.

14. A coating solution according to any preceding claims directed to coating solutions, wherein the coating solution consists, preferably consists essentially of:• a first thermoplastic polymer is present in a concentration from, 5.0 - 15 wt%• a second thermoplastic polymer is present in a concentration from 5.0 - 15 wt%• an adhesion promoter is present in a concentration from 2.0 - 8 wt%• a toughener is present in a concentration from 2.0 - 8 wt%• optionally a UV indicator in a concentration from 0 to 1.0wt%• optionally a hydrolysis stabilizer in a concentration from 0 to 1.0wt%, and• a solvent is present in a concentration from 80 - 90 wt% and is chosen from MEK, d- limonene, dimethyl carbonate, and dibasic esters.

15. A kit comprising: a primer solution according to any preceding claims directed to primer solutions, and an adhesive.

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