Supported thermally initiated debondable layer for power battery applications

Abstract

The present disclosure provides a thermally initiated debondable article comprising (i) a first debondable layer having a first major surface and a second major surface, and comprising at least one first thermoplastic polymer; (ii) a second debondable layer having a first major surface and a second major surface, and comprising at least one second thermoplastic polymer; (iii) a porous support layer between the first surface of the first debondable layer and the first surface of the second debondable layer; (iv) optionally, a first adhesive layer overlying the second major surface of the first debondable layer; (v) optionally, a second adhesive layer overlying a second major surface of the second debondable layer; (vi) optionally, a first liner on an outer surface of the first adhesive layer or the first debondable layer; and (vii) optionally, a second liner on an outer surface of the second adhesive layer or the second debondable layer.

Description

TECHNICAL FIELD

[0001] The present invention relates to a heat debondable adhesive article. Furthermore, the present disclosure also relates to a die cut and a kit assembly comprising the heat debondable adhesive article. The present disclosure also relates to a method for bonding and debonding an assembly. Furthermore, the present disclosure also relates to the use of the heat debondable article in the process of manufacturing a recyclable article, in particular a vehicle part or a battery part. BACKGROUND

[0002] Adhesives have been used in many structural applications. These structural applications include vehicle assembly, such as automotive and aircraft assembly. For example, epoxy-based adhesives are very stable in these applications. The technical field of manufacturing batteries for mobile electrification, such as automotive electrification, is currently developing rapidly, and the use of adhesives in this technical field is also becoming more and more extensive. As is common with these adhesives, very strong bonding, i.e. permanent bonding, between substrates is often required and achieved.

[0003] However, in many applications it can be desirable to release the bonding between different parts in a device or certain assembly. This is particularly the case when it is desirable to disassemble the parts or assembly in order to recycle at least a portion thereof.

[0004] Therefore, there is an increasing need in the art for adhesives or bonding techniques that not only provide a good bonding between parts, but also enable the parts to be debonded at a certain point in time when required. SUMMARY

[0005] The present disclosure provides a heat-initiated debondable adhesive article comprising

[0006] (i) a first debondable layer having a first major surface and a second major surface, and comprising at least one first thermoplastic polymer;

[0007] (ii) a second debondable layer having a first major surface and a second major surface, and comprising at least one second thermoplastic polymer;

[0008] (iii) a porous support layer located between the first surface of the first debondable layer and the first surface of the second debondable layer;

[0009] (iv) optionally, a first adhesive layer covering the second major surface of the first debondable layer;

[0010] (v) optionally, a second adhesive layer covering the second major surface of the second debondable layer;

[0011] (vi) optionally, a first liner on the outer surface of the first adhesive layer or the first debondable layer; and

[0012] (vii) optionally, a second liner on an outer surface of the second adhesive layer or the second debondable layer.

[0013] In a preferred embodiment, the first and second debondable layers are in contact with each other via a porous support layer.

[0014] The present disclosure also provides a die cut comprising a heat- debondable attachment article.

[0015] In addition, the present disclosure relates to a method for bonding and debonding a component assembly, the method comprising the steps of:

[0016] (I) attaching an article as described herein to at least a portion of a surface of a first component;

[0017] (II) optionally, applying at least one adhesive to a first major surface of a second component;

[0018] (III) attaching the second component to the article attached to the first component, such that the article connects the first component and the second component, thereby forming a component assembly;

[0019] (IV) optionally, curing the at least one adhesive;

[0020] (V) heating the component assembly so as to soften and / or at least partially melt the thermoplastic resin contained in the first and / or second debondable layer;

[0021] (VI) disconnecting the second component from the first component.

[0022] Furthermore, the present disclosure relates to the use of a heat- debondable article in the process of manufacturing a recyclable article, in particular a vehicle component or a battery component. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 A representative heat-initiated debondable attachment article according to the present disclosure is shown.

[0024] Figure 2 A comparative process for producing a heat-initiated debondable attachment article is shown. Figure 3 A first process for producing a heat-initiated debondable attachment article according to the present disclosure is shown.

[0025] Figure 4 A second process for producing a heat-initiated debondable attachment article according to the present disclosure is shown.

[0026] Figure 5 A picture of die cut manufacturing according to the present disclosure is shown.

[0027] Figure 6 Pictures showing die manufacturing according to the comparison process.

[0028] Figure 7 Pictures showing die manufacturing according to the comparison process. Figure 8 Pictures showing die manufacturing according to the comparison process.

[0029] Figure 9 Pictures showing die manufacturing according to the comparison process.

[0030] Figure 10 Pictures showing die manufacturing according to the comparison process. DETAILED DESCRIPTION

[0031] Before any embodiments of the present disclosure are explained in detail, it is to be understood that the application is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The application is capable of other embodiments and of being practiced or being carried out in various ways. Also, the term "one," "an," and "the" as used herein can mean one or more; and "and / or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items, for example, A and / or B can mean A and B individually, or A or B individually, or A and B together, or A and / or B together. Further, in the text, ranges include all of the numbers and amounts between the stated range limits (e.g., a range from 1 to 10 includes 1.4, 1.9, 2.33, 5.75, 9.98, etc.).

[0032] Also, in the text, the expression "at least one of' includes all numbers and amounts greater than one (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 "comprising," "containing" "including," or "having" and variations thereof, which are meant to be taken in their non-limiting sense, the use of "consisting of' and variations thereof is meant to be taken in their limiting sense. In addition, it is to be understood that the use of the term "including" as used herein can also be "consisting of' as the term "consisting of' is also encompassed by the term "including" as used herein, but in general, is used according to its normal meaning as used in the art. Thus, limiting "including" to "consisting of' or limiting "including" to "consisting of' is fully encompassed in the present disclosure.

[0033] The amount of the ingredients of the composition can be indicated in weight % (or "%wt" or "wt.-%"), unless otherwise specified. The amount of all ingredients is given 100 wt.%, unless otherwise specified. If the amount of an ingredient is identified in mole %, the amount of all ingredients is given 100 mole %, unless otherwise specified.

[0034] 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 (± 2 °C) under ambient pressure conditions of about 101 kPa.

[0035] Unless explicitly indicated otherwise, all embodiments and optional features of the present disclosure can be freely combined.

[0036] A first aspect of the present disclosure is a heat-induced debondable attachment article comprising

[0037] (i) a first debondable layer having a first major surface and a second major surface and comprising at least one first thermoplastic polymer;

[0038] (ii) a second debondable layer having a first major surface and a second major surface and comprising at least one second thermoplastic polymer;

[0039] (iii) a porous support layer located between the first surface of the first debondable layer and the first surface of the second debondable layer;

[0040] (iv) optionally, a first adhesive layer covering the second major surface of the first debondable layer;

[0041] (v) optionally, a second adhesive layer covering the second major surface of the second debondable layer;

[0042] (vi) optionally, a first liner on an outer surface of the first adhesive layer or the first debondable layer; and

[0043] (vii) optionally, a second liner on an outer surface of the second adhesive layer or the second debondable layer.

[0044] The article can be attached to a surface by pressure and / or heat, thereby providing sufficient bonding between the surface, i.e. different parts or articles. However, upon application of heat, at least one of the thermoplastic polymers in the at least one first debondable layer and / or the at least one second debondable layer can be at least partially melted. This has the effect of sufficiently weakening the bond to make it reversible, typically by using certain physical means such as a wedge or simply moving the parts in different directions. In this way, reliable bonding and debonding of parts and articles is surprisingly achieved. Furthermore, the heat-activated debondable article according to the present disclosure comprises a porous support layer located between the first surface of the first debondable layer and the first surface of the second debondable layer. The use of such a support structure facilitates the manufacture of die cuts, which is particularly desirable for a wide variety of applications, transportability of the article and ease of application of the article. Furthermore, the article can be easily attached to a surface of a first substrate, such as by heat and / or pressure. The assembly can then be further processed, stored and / or transported until a second substrate is attached to the assembly, e.g. by means of an adhesive. This is highly advantageous in many applications in industrial manufacturing processes.

[0045] In this regard, it is preferred that the porous support layer comprises at least one material selected from the group consisting of tissue paper, mesh, nonwoven, vlies, woven, scrim and any combination thereof, preferably nonwoven, mesh, vlies and any combination thereof. Preferably, the porous support layer comprises at least one material selected from the group consisting of natural fibers and synthetic fibers, preferably selected from synthetic fibers, more preferably selected from polyethylene fibers. Further, it is advantageous that the porous support layer exhibits an area weight in the range of 1 g / m2to 30 g / m2, preferably 2 g / m2to 25 g / m2, more preferably 3 g / m2to 20 g / m2, and most preferably 4 g / m2to 15 g / m2. Preferably, the porous support layer exhibits a thickness in the range of 20 micrometer to 200 micrometer, preferably 40 micrometer to 180 micrometer, and more preferably 50 micrometer to 120 micrometer. In one preferred exemplary embodiment of the present disclosure, the porous support layer is a mesh. 2 to 30 g / m2, 2 , preferably 2 g / m2 2 to 25 g / m2 2 , and more preferably 3 g / m2 2 to 20 g / m2 2 Preferably, the porous support layer exhibits a thickness in the range of 20 micrometer to 200 micrometer, preferably 40 micrometer to 180 micrometer, and more preferably 50 micrometer to 120 micrometer. In one preferred exemplary embodiment of the present disclosure, the porous support layer is a mesh.

[0046] The at least one thermoplastic polymer in the at least one first debondable layer and / or second debondable layer is preferably a polymer exhibiting a glass transition temperature in the range of 20 °C to 100 °C, preferably 25 °C to 80 °C and more preferably 35 °C to 75 °C. This has the effect that the thermoplastic polymer at least partially melts upon application of heat and thus the article loses at least some stability, i.e. adhesive properties. This enables the desired debonding as described herein. The at least one thermoplastic polymer is advantageously selected from the group consisting of polyesters, poly(meth)acrylates, acrylonitrile butadiene styrene, polyamides, polybenzimidazoles, polycarbonates, polyether sulfones, polyoxymethylenes, polyether ether ketones, polyether imides, polyethylenes, polyphenylene ethers, polyphenylene sulfides, polypropylenes, polystyrenes, polyvinyl chlorides and any combination thereof, preferably polyesters. In this regard, it is preferred that the at least one thermoplastic resin exhibits a number average molecular weight in the range of 5,000 g / mol to 50,000 g / mol, preferably 7,000 g / mol to 40,000 g / mol and more preferably 8,000 g / mol to 30,000 g / mol (determined by GPC).

[0047] It is further preferred that the at least one first debondable layer and / or at least one second debondable layer comprises at least one toughener. This has the effect of improving the adhesive properties, such as lap shear strength and / or tensile strength at room temperature, without compromising the performance at the maximum working temperature. Furthermore, this also has the effect of reducing the brittleness of the first debondable layer and / or second debondable layer. Preferably, the at least one toughener is selected from the group consisting of butadiene rubber, nitrile rubber and core-shell rubber, more preferably from core-shell rubber. Exemplary compounds which can advantageously be used as butadiene rubber or nitrile rubber are carboxyl, amine, epoxy, hydroxyl or methacrylate end-capped butadiene, butadiene styrene or butadiene acrylonitrile copolymers, preferably amine end-capped butadiene styrene or butadiene acrylonitrile copolymers. Such tougheners are commercially available, for example, under the trade name Hypro CTBN, ATBN, ETBN, HTB or VTBNX from CVC Thermoset Specialities, under the trade name Hycar ATBN from Amerald Materials, or under the trade name MX series from Kaneka, such as MX 257.

[0048] As for the core-shell rubber as a toughening agent, any core-shell rubber toughening agent generally known in the art can be used in the context of the present disclosure. In typical embodiments, the core-shell rubber toughening agent is a composite material constructed from materials different from each other in the core portion inside and the shell portion outside. In this context, the term "different materials" refers to materials different from each other in composition and / or properties, and thus includes, for example, materials using the same type of resin but different from each other in molecular weight, etc.

[0049] From the viewpoint of advantageously achieving the toughening effect of the composition 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 due to the core portion having a relatively low Tg serving as a stress center point, the shell portion suppresses the core-shell rubber from undergoing disadvantageous agglomeration, and thus the core-shell toughening agent can be uniformly dispersed in the composition as described herein.

[0050] Examples of the core-shell rubber toughening agent 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-butadiene-acrylic rubber copolymer, methyl methacrylate-butadiene-acrylic rubber-styrene copolymer, methyl methacrylate-(acrylic silicone IPN rubber) copolymer, etc., but are not limited thereto. The methyl methacrylate-butadiene copolymer, the methyl methacrylate-butadiene-styrene copolymer, and the methyl methacrylate-butadiene-acrylic rubber-styrene copolymer can be advantageously used as the core-shell toughening agent.

[0051] The core-shell toughening agent is generally in the form of fine particles, and the average value of the primary particle diameter (weight average particle diameter) is generally about 0.05 micrometers or more or about 0.1 micrometers or more to about 5 micrometers or less or about 1 micrometer or less.

[0052] Preferably, the core-shell rubber can be used in a state dispersed in a matrix. It is preferable that the matrix is an epoxy resin. From the viewpoint of good dispersion of the core-shell rubber in the composition as described herein, a matrix having good affinity to the first epoxy resin or the second epoxy resin as described herein is particularly preferable. Examples of the matrix can include epoxy resins such as bisphenol A, etc.

[0053] The core-shell toughening agent can be a commercial product provided as a resin modifier 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 Kukdo Chemical, in which methyl methacrylate-butadiene-styrene (MBS) is dispersed in bisphenol A diglycidyl ether) as a resin, and MC-257 (commercially available from Kukdo Chemical, dispersed in an epoxy resin) as a butadiene core-shell resin, and F351 (commercially available from Aika Industries) as an acrylic core-shell resin, Paraloid 2650A (butadiene rubber), Hycar ATBN (CVC Chemicals, liquid butadiene rubber), and the like.

[0054] With respect to the effects brought about by the presence of at least one first toughening agent in the composition as described herein, it is preferred that the at least one toughening agent is included in the at least one first debondable layer in an amount ranging from 1 wt% to 25 wt%, preferably from 2.5 wt% to 20 wt%, more preferably from 5 wt% 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 toughening agent is included in the at least one second debondable layer in an amount ranging from 1 wt% to 25 wt%, preferably from 2.5 wt% to 20 wt%, more preferably from 5 wt% to 15 wt%, based on the total weight of the at least one second debondable layer. Further, with respect to the effects described herein, it is preferred that the at least one first debondable layer exhibits a thickness ranging from 1 micron to 300 microns, preferably from 3 microns to 250 microns, more preferably from 5 microns to 200 microns. Similarly, it is preferred that the at least one second debondable layer exhibits a thickness ranging from 1 micron to 300 microns, preferably from 3 microns to 250 microns, more preferably from 5 microns to 200 microns.

[0055] The complete article can advantageously exhibit a total thickness ranging from 40 microns to 500 microns, preferably from 70 microns to 450 microns, more preferably from 90 microns to 400 microns. Alternatively, the complete article can advantageously exhibit a total thickness ranging from 40 microns to 500 microns, preferably from 70 microns to 450 microns, more preferably from 90 microns to 400 microns.

[0056] The heat-debondable attachment article according to the present disclosure can further include a first adhesive layer disposed on at least a portion of the second major surface of the first debondable layer. This can enhance the ease of application and / or adhesive properties of the article. Similarly, the heat-debondable attachment article according to the present disclosure can further include 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 the group consisting of a structural adhesive, a semi-structural adhesive, and a pressure sensitive adhesive, preferably a pressure sensitive adhesive.

[0057] It is further preferred that the attachment article as described herein comprises perforations. In this regard, it is preferred that either or both of the first debondable layer and the second debondable layer comprise perforations. This can have the effect of effectively encapsulating the heat-initiated debondable layer, thereby enhancing the bonding and debonding capabilities of the article as described herein. Alternatively, the perforations can extend from the first major surface through the entire thickness of the article to the second major surface. It is further preferred that at least a portion of the article comprises perforations. Thus, the adhesive bonding and debonding properties can be distributed as desired along the length of or over certain areas of the article as described herein.

[0058] Preferably, the article provides a lap shear strength in the range of 5 MPa to 10 MPa at a temperature range between 20 °C and 65 °C, and a lap shear strength of less than 5 MPa, preferably less than 3 MPa, more preferably less than 1.5 MPa at a temperature in the range of 80 °C to 100 °C.

[0059] The present disclosure also provides a die cut, which comprises the article as described herein. The die cut has many advantages in terms of transportability, application, and, in particular, it can provide a precise fit for various shapes and applications.

[0060] The present disclosure also provides a parts assembly having a first end and a second end, comprising a first part, a second part and a heat-induced debondable attachment article as described herein located between the first part and the second part. The first and second parts can be selected from a wide variety of shapes and materials. For example, they can be selected from metal or composite panels as used in car bodies or in aeronautical interior or exterior parts. Further, in advantageous embodiments of the present disclosure, they can be selected from battery housing parts, i.e. one of the first and second parts can be a battery housing and the other part can be a battery cover or the like. Advantageously, this facilitates the recyclability of the battery system. It is further preferred that the parts assembly further comprises at least one adhesive disposed between the attachment article and at least one first part and / or at least one second part. The at least one adhesive is preferably selected from structural adhesives and semi-structural adhesives, such as from two-component structural adhesives. Advantageously, the heat-induced debondable attachment article bonds the first panel and the second part together. The parts assembly can comprise the attachment article over the entire length between the first end and the second end. Alternatively, the attachment article can be disposed only close to the first end and / or the second end. This can bring the advantage that a first cleaving between the first part and the second part can be achieved only at this location, which subsequently weakens the bond between the first part and the second part over the entire length. Thus, debonding can be easily achieved even if the bond between the first part and the second part has a strong or even very strong bond over a major length, e.g. in case a strong structural adhesive is employed. For example, the attachment article can be disposed at a length in the range of 0.1 cm to 30 cm, preferably 0.2 cm to 20 cm, more preferably 0.3 cm to 15 cm, starting from the first end and / or the second end of the parts assembly.

[0061] Another aspect of the present disclosure is a method for bonding and debonding a parts assembly, the method comprising the steps of:

[0062] (I) attaching an article as described herein to at least a portion of a surface of a first part;

[0063] (II) optionally, applying at least one adhesive to a first major surface of a second part;

[0064] (III) attaching the second part to the article attached to the first part, such that the article connects the first part and the second part, thereby forming a parts assembly;

[0065] (IV) optionally, curing the at least one adhesive;

[0066] (V) heating the parts assembly in order to soften and / or at least partially melt the thermoplastic resin contained in the first and / or second debondable layer;

[0067] (VI) disconnecting the second part from the first part.

[0068] The attachment in step (I) can comprise the application of pressure and / or heat. The pressure and / or heat are chosen such that the at least one thermoplastic resin comprised in the at least one first and the at least one second heat-debondable layer at least partially softens and / or at least partially melts, thereby achieving some kind of bonding or lamination of the article to the part. Preferably, the material of the first part and / or the material of the second part is selected from the group consisting of metals, polymers, composite materials, carbon fiber materials, and ceramic materials. It is further preferred that the method as described herein is a method of manufacturing and recycling an automotive panel assembly or a battery assembly.

[0069] Yet another aspect of the present disclosure is the use of a heat-initiated debondable article as described herein or a die-cut piece as described herein in a process of manufacturing a recyclable article. Preferably, the article is selected from the group consisting of a panel, a body part, a battery part, an interior part, an exterior part. It is further preferred that the manufacturing takes place in the automotive industry, the commercial transportation industry, the civil engineering industry, the aviation industry, or the shipbuilding industry. It is particularly preferred that the recyclable article is part of a battery and that the battery is part of an electric power system or a photovoltaic system of an automobile, a truck, a train, an airplane, a spacecraft, a watercraft such as a ship or a boat, a tool, a household appliance, or a building.

[0070] Examples

[0071] The present disclosure is further described, however, without intending to limit the present disclosure thereto. The following examples are provided to illustrate certain embodiments but are not intended to limit in any way. Prior thereto, some test methods for characterizing materials and their properties will be described. Unless otherwise indicated, all parts and percentages are by weight.

[0072] Test Methods

[0073] Overlap Shear Strength

[0074] The lap shear strength was determined according to DIN EN 1465 (published in 2009). The test details are described in the examples section.

[0075] Tensile Strength

[0076] The tensile strength was determined according to LWF-KS-2 method [patent DE 195 22 247 A1].

[0077] Split Strength

[0078] The split strength was determined according to ASTM D1062 using an Instron 5500R tensile tester.

[0079] Example 1 and Comparative Examples 1 and 2 :

[0080]

[0081] A HotMelt foil extrusion of a blend (50:50 wt%) containing Marnex AH441 and Marnex AH645 was extruded on a siliconized PET liner. The thickness of the functional layer can be adjusted between e.g. 10 pm to 200 pm as needed. For mechanical analysis (OLS) of Comparative Example 1, a 50 pm thick functional layer was used, which was laminated to a given substrate by applying heat (105°C) and pressure for 5 minutes (according to the process of Figure 2 For Patent Example 1, two 50 pm thick functional layers (same as for Comparative Example 1) were used in combination with a support layer (Optiveil ™ , fine polyester veil, 8 g / m 2 ). The final functional layer was assembled by applying heat (105°C) and pressure for 5 minutes and was the starting material for the process shown in Figure 3 and Figure 4 .

[0082] The OLS samples of Example 1 were assembled according to the process shown in Figure 4 . As substrates, two combined scenarios were used: galvanized steel or AlClad 2024 + PSA + BR127. In all cases, the gap size between the assembled substrates was 1.0 mm, adjusted by PTFE spacers. In all cases, PUR based DP6330 from 3M was used as adhesive. For mechanical analysis (OLS) of Comparative Example 2, DP6330 was used alone, without any functional layer. To demonstrate the ability to manufacture die cuts, a hydraulic press was used, including a “dog bone shape” die mold. The supported functional layer of Example 1 was compared to an unsupported design (50 pm, 80 pm, 170 pm). In all cases, 10 specimens were tried to be manufactured.

[0083]

[0084] As can be seen in Table 2, compared to the process according to Figure 2 , the process according to Figure 4The new process of Example 1 showed significantly better strength between RT - 60°C. At 90°C, both Example 1 and Comparative Example 1 obtained values low enough that the test specimen was easily delaminated. With regard to the failure mode obtained, a significant difference can also be seen. Cohesive failure was observed in all cases of Example 1. In the case of Comparative Example 1, adhesive failure was most likely to occur. The individual DP6330 without any functional layer showed excellent bond strength between RT - 60°C (Comparative Example 2). No significant performance drop was found at 90°C in this case.

[0085] One particular advantage of the tape support design is the ability to manufacture die cuts. Ten out of ten die cuts were successfully manufactured. Die cuts were not successfully manufactured by the unsupported product design.

[0086] Example 2 and Comparative Example 3 :

[0087]

[0088] HotMelt foils containing a blend of Marnex AH 441 : Marnex AH 645: Paraloid EXL-2650J (Example 2) (45:45:10 wt%) and a blend of Marnex AH 441 : Marnex AH 645 (Comparative Example 3) (50:50 wt%) were manufactured inlayed in Optiveil fine polyester veil. In both cases, the thickness of the tape support functional layer was ~320 pm.

[0089] For mechanical analysis, the overlap shear strength (OLS) and tensile strength were tested. According to Figure 4 Test specimens were manufactured. As a substrate, galvanised steel was used and the gap size between the assembled substrates was 1.00 mm in all cases (Table 4).

[0090]

[0091] As can be seen in Table 4, the addition of a core shell rubber (CSR) based toughener resulted in an OLS / tensile strength boost of the assemblies tested at room temperature.

[0092] Example 3 and Comparative Example 4

[0093]

[0094] A HotMelt foil containing a blend of Marnex AH441 and Marnex AH645 (50:50 wt%) was extruded on a siliconized PET liner. The thickness of the functional layer can be adjusted between e.g. 10 pm to 200 pm as required. For Patent Example 3, two 80 pm thick functional layers were used in combination with a support layer (Optiveil ™ , fine polyester veil, 8 g / m 2 ). According to Example 1, the final tape support functional layer assembly was performed by applying heat (105 °C) and pressure for 5 minutes.

[0095] As a substrate for the cleave test, 6063 T6 10 SWG 25 mm wide 25 mm high 200 mm long aluminium square tube was used. The bonding surface was grit blasted to 2 Ra and subsequently coated with EW5000AS cured for 1 hour in a preheated oven at 140 °C. For Patent Example 3, the primed tube was heated to 120 °C and the tape support functional layer (5 mm x 50 mm) was adhered to the surface (2 mm from the tube end coated, see Figure 7 and Figure 8 ) and then left in the oven for 5 minutes to ensure wet out and then cooled to room temperature (see Firing 1, New Process, Path 1). In the next step, Scotch ® 3434 masking tape was used to mark out 10 mm wide strips on all tubes. A thermocouple was positioned in the centre of the tape support functional layer strip. 3M Structural Adhesive 9860 was applied to the tube and 1 mm glass beads were added to adjust the bead thickness. For assembly, a second primed tube was also covered with SA 9860 beads and finally pressed on top of the first tube. For Comparative Example 4, the same steps were performed although no tape support functional layer was used. All specimens were allowed to cure at room temperature for 7 days. For testing, the samples were clamped in the testing machine and heated to 90 °C using a heat gun (see Figure 9 ). Before starting the test, all specimens (n=3 per group) were left at 90 °C for 30 seconds (test speed: 300 kgf / min).

[0096] As can be seen in Table 6, the use of a tape support functional layer resulted in a reduction of the heat induced cleave force (90 °C) of about 44% compared to Comparative Example 3 which did not contain a tape support functional layer.

[0097]

[0098] Based on the results of Example 3, the tape support functional layer can also be used only in small patches, thereby making the first opening process of the assembly easy to implement. In addition to the use of small patches, another variant is to use a perforated tape support functional layer (see Figure 10 ).

Claims

1. A heat-activated releasable attachment article comprising: (i) a first releasable layer having a first major surface and a second major surface and comprising at least one first thermoplastic polymer; (ii) a second releasable layer having a first major surface and a second major surface and comprising at least one second thermoplastic polymer; (iii) a porous support layer between the first surface of the first releasable layer and the first surface of the second releasable layer; (iv) optionally, a first adhesive layer covering the second major surface of the first releasable layer; (v) optionally, a second adhesive layer covering the second major surface of the second releasable layer; (vi) optionally, a first liner on an outer surface of the first adhesive layer or the first releasable layer; and (vii) optionally, a second liner on an outer surface of the second adhesive layer or the second releasable layer.

2. The heat-activated releasable attachment article according to claim 1, wherein the first releasable layer and the second releasable layer are in contact with each other through the porous support layer.

3. The heat-activated releasable attachment article according to claim 1, wherein the porous support layer comprises at least one material selected from the group consisting of tissue paper, mesh, nonwoven, gauze, woven, scrim, and any combination thereof, preferably nonwoven, mesh, gauze, and any combination thereof.

4. The heat-activated releasable attachment article according to any one of the preceding claims, wherein the porous support layer comprises at least one material selected from the group consisting of natural fibers and synthetic fibers, preferably selected from synthetic fibers, more preferably selected from polyethylene fibers.

6. The heat-activated releasable attachment article according to any one of the preceding claims, wherein the porous support layer exhibits a thickness in the range of 20 micrometers to 200 micrometers, preferably 40 micrometers to 180 micrometers, and more preferably 50 micrometers to 120 micrometers.

5. The thermally initiated debondable attachment article of any one of the preceding claims, wherein the porous support layer exhibits an area weight in the range of 1 g / m2 2 to 30 g / m2 2 , preferably 2 g / m2 2 to 25 g / m2 2 , and more preferably 3 g / m2 2 to 20 g / m2 2 .

7. The heat-activated releasable attachment article according to any one of the preceding claims, wherein at least one thermoplastic polymer exhibits a glass transition temperature in the range of 20 °C to 100 °C, preferably 25 °C to 80 °C, and more preferably 35 °C to 75 °C.

8. The heat-activated releasable attachment article according to any one of the preceding claims, wherein at least one thermoplastic polymer is selected from the group consisting of polyesters, poly(meth)acrylates, acrylonitrile butadiene styrene, polyamides, polybenzimidazoles, polycarbonates, polyether sulfones, polyoxymethylenes, polyether ether ketones, polyether imides, polyethylenes, polyphenylene oxides, polyphenylene sulfides, polypropylenes, polystyrenes, polyvinyl chlorides, and any combination thereof, preferably polyesters. ​ 9. The heat-initiated debondable attachment article according to any one of the preceding claims, wherein the at least one thermoplastic resin exhibits a number average molecular weight in the range of 5,000 g / mol to 50,000 g / mol, preferably 7,000 g / mol to 40,000 g / mol and more preferably 8,000 g / mol to 30,000 g / mol.

10. The heat-initiated debondable attachment article according to any one of the preceding claims, wherein the at least one first and / or second debondable layer comprises at least one toughener, and wherein the at least one toughener is selected from the group consisting of butadiene rubber, nitrile rubber and core-shell rubber, more preferably from core-shell rubber.

11. The heat-initiated debondable attachment article according to any one of the preceding claims, wherein the article comprises perforations.

12. A die-cut piece comprising the article according to any one of the preceding claims.

13. A component assembly having a first end and a second end, the component assembly comprising a first component, a second component and a heat-initiated debondable attachment article according to any one of claims 1 to 12 disposed between the first and second components.

14. A method for bonding and debonding a component assembly, the method comprising the steps of: (I) attaching the article according to any one of claims 1 to 12 to at least a portion of a surface of a first component; (II) optionally, applying at least one adhesive to a first major surface of a second component; (III) attaching the second component to the article attached to the first component such that the article connects the first and second components, thereby forming a component assembly; (IV) optionally, allowing the at least one adhesive to cure; (V) heating the component assembly so as to soften and / or at least partially melt the thermoplastic resin comprised in the first and / or second debondable layer; (VI) disconnecting the second component from the first component.

15. Use of the heat-initiated debondable attachment article according to any one of claims 1 to 12 or the die-cut piece according to claim 13 in a process for manufacturing a recyclable article.

Images