Room temperature curable stable adhesive composition

Abstract

The present disclosure provides a curable adhesive composition precursor comprising: a first portion (A) comprising (i) at least one first epoxy curing agent; (ii) at least one first curing aid comprising at least one ammonium salt; a second portion (B) comprising (i) at least one epoxy resin; and (ii) optionally, at least one first impact modifier.

Description

Technical Field

[0001] The present disclosure relates to a curable two-part adhesive composition precursor and an adhesive composition obtained therefrom. In addition, the present disclosure also relates to a method for adhesively connecting parts. In addition, the present disclosure also relates to the use of the curable adhesive composition and its precursor as described herein in industrial manufacturing and assembly operations, particularly in the body-in-white process in the automotive industry. Background Art

[0002] Adhesives have been used in many structural applications. These structural applications include vehicle assembly, such as automobile and aircraft assembly. For example, epoxy-based adhesives are very stable in these applications. In applications particularly in the automotive industry, it has also been determined that epoxy-based adhesives need to exhibit a high degree of toughness in order to improve the impact resistance of the bonded joint. Typically, it is expected in the art that such impact performance needs to cover a wide temperature range, including temperatures below -20°C or even -40°C, depending on the operating temperature of the bonded structure.

[0003] Furthermore, in several applications, epoxy-based adhesives often need to meet challenging requirements regarding bond strength and mechanical properties at elevated temperatures, for example at temperatures up to 100° C. to 120° C.

[0004] A conventional solution to meet these challenging requirements has been described in the prior art to use heat-curable epoxy adhesives. Most of these adhesives are so-called one-part systems, which generally require high temperature curing. In addition, two-part systems have also been described. However, it is also known that these two-part systems generally require a post-cure at a temperature above 80° C. after the initial curing step to develop full bond strength. In addition, in order to reduce the curing temperature, it is known to use so-called curing accelerators or curing aids. However, this may add additional challenges, such as challenges with respect to the viscosity of the adhesive composition.

[0005] While there are currently numerous examples of structural adhesives commercially available for use in manufacturing operations in the automotive industry, such as body-in-white applications, there remains a need for improved adhesives that do not require curing at elevated temperatures and / or do not require an additional curing step at elevated temperatures, that exhibit good processability, and that exhibit good adhesion properties after curing at ambient temperatures, and good impact resistance, particularly as desired by the automotive industry. Summary of the invention

[0006] The present disclosure provides a curable adhesive composition precursor, the curable adhesive composition precursor comprising:

[0007] The first part (A), the first part (A) comprising

[0008] (i) at least one first epoxy curing agent;

[0009] (ii) at least one first curing aid, the at least one first curing aid comprising at least one ammonium salt;

[0010] The second part (B), the second part (B) comprises

[0011] (i) at least one epoxy resin; and

[0012] (ii) Optionally, at least one first impact modifier.

[0013] The present disclosure also provides a curable adhesive composition obtained by curing part (A) and part (B) of the curable adhesive composition precursor as described herein.

[0014] In addition, the present disclosure relates to a method for bonding components, the method comprising the steps of:

[0015] (a) providing an adhesive composition as described herein;

[0016] (b) applying the adhesive composition to at least a portion of the surface of the first component;

[0017] (c) applying a second component to the adhesive composition applied to the first component;

[0018] (d) performing a curing step to cure the adhesive composition as described herein to adhesively bond the first component to the second component.

[0019] Furthermore, the present disclosure relates to the use of a curable adhesive composition precursor as described herein or a curable adhesive composition as described herein for bonding parts. DETAILED DESCRIPTION

[0020] Before explaining any embodiment of the present disclosure in detail, it should be understood that the application of the present disclosure is not limited to the details of the construction and component arrangement given in the following description. The composition and method of the present disclosure can have other embodiments and can be implemented or executed in various ways. As used herein, the terms "one", "a kind of" and "said" are used interchangeably and mean one or more; and "and / or" is used to indicate that one or two described situations may occur, such as A and / or B including (A and B) and (A or B). Moreover, in this article, the range expressed by the endpoint includes all numbers contained in the range (for example, 1 to 10 including 1.4, 1.9, 2.33, 5.75, 9.98, etc.). Moreover, in this article, the expression "at least one" includes one and all numbers greater than one (for example, 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.). Moreover, it should be understood that the wording and terms used herein are for illustrative purposes and should not be regarded as restrictive. In contrast to the use of "consisting of," which is intended to be limiting, the use of "includes," "contains," "includes," or "has," and variations thereof, is intended to be non-limiting and encompass the items listed thereafter as well as additional items. Furthermore, it is understood that the term "comprising," as used herein, may also encompass the term "consisting of" in the sense of "consisting only of," but is generally used according to its commonly used meaning in the art. Thus, limiting "comprise" to "consists of" or limiting "comprising" to "consisting of" is fully encompassed by the present disclosure.

[0021] Unless otherwise indicated, the amount of a component of a composition may be indicated in % by weight (or "% wt" or "wt.-%). Unless otherwise indicated, the amounts of all components are given as 100 wt.%. If the amount of a component is indicated in mole %, the amounts of all components are given as 100 mole % unless otherwise indicated.

[0022] 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.

[0023] Unless explicitly stated otherwise, all embodiments and optional features of the present disclosure can be freely combined.

[0024] A first aspect of the present disclosure is a curable adhesive composition precursor, the curable adhesive composition precursor comprising:

[0025] The first part (A), the first part (A) comprising

[0026] (i) at least one first epoxy curing agent;

[0027] (ii) at least one first curing aid, the at least one first curing aid comprising at least one ammonium salt;

[0028] The second part (B), the second part (B) comprises

[0029] (i) at least one epoxy resin; and

[0030] (ii) Optionally, at least one first impact modifier.

[0031] Curable adhesive composition precursors (such as curable adhesive composition precursors according to the present disclosure) are also referred to as 2-component compositions or 2k compositions. It should be understood that the first part (A) of the curable adhesive composition precursor is physically separated from the second part (B). According to the needs of the user, the first part (A) and the second part (B) are combined and thus mixed before the intended use to obtain a curable adhesive composition. The present disclosure also covers curable adhesive compositions obtained from curable adhesive composition precursors and cured compositions obtained by curing the curable adhesive composition. The use of these 2k compositions provides several advantages, such as a longer storage life; the possibility of forming a curable composition according to the needs of the user; and obtaining a composition that can be easily cured, which itself provides the user with the advantage of further processing, especially in the technical field of bonding metal parts with specific requirements commonly seen in body-in-white processes in the automotive industry.

[0032] The curable adhesive composition precursor according to the present disclosure may exhibit at least one or even a combination of desirable properties, such as good handling properties (such as viscosity expected for common application techniques), fast curing time of the curable adhesive composition obtained therefrom, good mechanical strength of the cured composition (especially good impact resistance at low temperatures), and good adhesion properties (such as lap shear strength at elevated temperatures). This combination of ambient curing temperature and generally good handling and adhesion properties makes the compositions according to the present disclosure highly suitable for use in the automotive industry and in electronic device or battery manufacturing.

[0033] Epoxy curing agents suitable for the present disclosure are compounds capable of crosslinking (curing) epoxy resins. Preferably, the epoxy curing agent as described herein is an amine epoxy curing agent, due to the well-known curing characteristics and generally good commercial availability and the excellent results obtained. Suitable curing agents according to the present disclosure can be primary amines or secondary amines. The epoxy curing agent system present in part (A) comprises at least one first epoxy curing agent. Preferably, the at least one first epoxy curing agent is selected from diamines, polyamidoamines, alkylphenol aldehyde amides (phenalkamide), alkylphenol aldehyde amines (phenalkamine), epoxy-amine adducts, polyetheramines, alicyclic amines and any combination and mixture thereof. In a preferred example, at least one first epoxy curing agent is selected from multifunctional amine epoxy curing agents. Combined with other ingredients of the curable adhesive precursor as described herein, it is found that multifunctional amine epoxy curing agents produce desired high temperature properties after curing. In another preferred example of the present disclosure, at least one first epoxy curing agent is selected from polyetheramines and epoxy-amine adducts, preferably selected from polyetheramine-epoxy adducts and any combination and mixture thereof. These compounds have also been found to impart good mechanical properties to the cured adhesive, such as high lap peel strength.

[0034] It is further preferred that part (A) of the curable adhesive composition precursor further comprises at least one second epoxy curing agent different from the at least one first epoxy curing agent. The at least one second epoxy curing agent is preferably selected from diamines, polyamidoamines, alkylphenol amides, alkylphenol amines, epoxy-amine adducts, polyetheramines, cycloaliphatic amines and any combinations and mixtures thereof.

[0035] In specific aspects, the diamines useful herein may comprise the following general structure:

[0036]

[0037] in

[0038] Residue R 1 , R 2 and R 4 independently of one another may represent hydrogen or a hydrocarbon (such as an alkyl) or an alkoxy or polyoxyalkyl residue containing about 1 to 15 carbon atoms;

[0039] R 3 represents a polyether alkyl residue preferably containing about 1 to 15 carbon atoms;

[0040] n represents an integer from 1 to 10;

[0041] Select residue R 1 , R 2 and R 4 , so that the amine contains two primary amine groups.

[0042] In a specific aspect, the diamine is a polyetheramine having two primary amine moieties.The polyetheramine may have 1 to 12, or even 1 to 6, chain ether (oxygen) atoms.

[0043] In a preferred aspect, the first epoxy curing agent comprises at least one polyetheramine derived from polypropylene oxide or polyethylene oxide. Exemplary polyetheramines suitable for use herein are commercially available under the trade name JEFFAMINE from Huntsman Chemicals or under the trade name TTD (4,7,10-trioxatridecane-1,13-diamine), for example, from BASF, Ludwigshafen Germany.

[0044] Similarly, the diamine used herein is preferably a polymeric diamine, such as an amidoamine or a polyamidoamine. The polyamidoamine may be a branched or unbranched aromatic polyamidoamine or a branched or unbranched aliphatic polyamidoamine. Preferably, the polyamidoamine is an aliphatic polyamidoamine. The polyamidoamine that can be advantageously used in the context of the present disclosure is obtained as described in

[0010] to

[0029] of EP249527A1, the disclosure of which is incorporated herein by reference.

[0045] Preferably, the at least one first epoxy curing agent is selected from multifunctional amine-based epoxy curing agents, polyetheramines and epoxy-amine adducts, and wherein the at least one second epoxy curing agent is selected from epoxy-amine adducts and polyetheramines. This particular combination of the first epoxy curing agent and the second epoxy curing agent was found to produce good high temperature properties, such as good lap shear strength of the cured adhesive composition as described herein, together with the other ingredients of the composition as described herein.

[0046] In this regard, it is preferred that part (A) comprises at least one second epoxy curing agent in an amount of 1 wt % to 25 wt %, preferably 2 wt % to 20 wt %, and more preferably 3 wt % to 10 wt %, based on the total weight of part (A). Similarly, it is preferred that part (A) comprises at least one first epoxy curing agent in an amount of 20 wt % to 90 wt %, preferably 30 wt % to 85 wt %, and more preferably 40 wt % to 80 wt %, based on the total weight of part (A).

[0047] Part (A) also comprises at least one curing aid, which includes at least one ammonium salt. This has the following effect: the viscosity of the adhesive composition is maintained within the desired range, while the curing acceleration performance (such as the curing ability of the adhesive composition under ambient conditions as described herein) is not affected. This is especially true when at least one second curing aid further described herein is used in combination with the at least one curing aid. The at least one ammonium salt of the at least one first curing aid may include an inorganic or organic ammonium salt. In this regard, the at least one ammonium salt of the at least one first curing aid may include at least one organic or inorganic anion. Preferably, the at least one ammonium salt of the at least one first curing aid is an ammonium salt according to formula 1

[0048] NR 1 R 2 R 3 R 4 X(Formula 1)

[0049] in

[0050] R 1 , R 2 , R 3 and R 4 Each of the above may be the same or different and is independently selected from H, linear or branched alkyl or alkoxy, preferably selected from H and linear or branched alkyl; X is selected from chloride, bromide, nitrate, sulfate, triflate, preferably selected from nitrate and triflate, more preferably nitrate. Ammonium nitrate is particularly preferred due to its favorable properties and commercial availability.

[0051] It is also preferred that the at least one first curing aid also includes a metal salt. In this regard, it is preferred that the at least one metal salt includes at least one anion, the at least one anion is selected from chloride, bromide, nitrate, sulfate, thiosulfate, triflate, phosphate and any combination and mixture thereof, preferably selected from nitrate and triflate, and more preferably nitrate. The at least one metal salt preferably includes a metal cation, the metal cation is selected from magnesium ion, calcium ion, strontium ion, preferably selected from magnesium ion and calcium ion, more preferably calcium ion. Particularly preferred is calcium nitrate, which generally produces good results in accelerating the curing reaction with epoxy compounds, even under ambient conditions, a good curing speed is obtained. In a particularly preferred example of a curable adhesive composition precursor according to the present disclosure, the at least one first curing aid includes calcium nitrate and ammonium nitrate. This combination ensures excellent curing speed and good processability, such as the desired viscosity of the curable adhesive composition described herein.

[0052] It is further preferred that part (A) further comprises at least one second curing aid different from at least one first curing aid. Preferably, at least one second curing aid different from at least one first curing aid is selected from the group consisting of imidazole, imidazole salt, imidazoline or aromatic tertiary amine. Together with at least one first curing aid as described herein, a synergistic beneficial effect on curing speed and application performance is produced. Preferably, at least one second curing aid different from at least one first curing aid is selected from aromatic tertiary amines, including aromatic tertiary amines having a structure of formula (2):

[0053]

[0054] in

[0055] R 1 is H or alkyl, such as for example methyl or ethyl, preferably methyl;

[0056] R 2 For CHNR 5 R 6 ;

[0057] R 3 and R 4 may be present or absent independently of each other, and when present, R 3 and R 4 For CHNR 5 R 6 ;

[0058] R 5 and R 6 Each is independently alkyl, preferably CH3 or CH2CH3.

[0059] At least one first curing aid is contained in part (A) in an amount ranging from 0.1 wt% to 20 wt%, preferably from 0.5 wt% to 15 wt%, more preferably from 1 wt% to 10 wt%, based on the total weight of part (A). Similarly, at least one second curing aid is preferably contained in part (A) in an amount ranging from 0.1 wt% to 20 wt%, preferably from 0.5 wt% to 15 wt%, more preferably from 1 wt% to 10 wt%, based on the total weight of part (A). Preferably, part (A) comprises at least one first curing aid and at least one second curing aid in a total amount ranging from 0.2 wt% to 40 wt%, preferably from 1 wt% to 30 wt%, and more preferably from 2 wt% to 20 wt%, based on the total weight of part (A). Advantageously, the weight ratio of at least one first curing aid to at least one second curing aid may be in the range of 10:1 to 1:10, preferably 5:1 to 1:5, more preferably 2:1 to 1:2, most preferably about 1:1.

[0060] According to the part (A) of the curable adhesive composition precursor of the present disclosure and optionally part (B) may also include at least one inorganic filler material. Part (A) may include at least one filler, the amount of the at least one filler based on the total weight of the part (A) of the composition as described herein is in the range of 2 wt % to 35 wt %, preferably 5 wt % to 30 wt % and more preferably 8 wt % to 25 wt %. Similarly, part (B) may include at least one inorganic filler material, the amount of the at least one inorganic filler material based on the total weight of the part (B) of the composition as described herein is in the range of 2 wt % to 35 wt %, preferably 5 wt % to 30 wt % and more preferably 8 wt % to 25 wt %. Inorganic filler material may have at least one advantageous effect, such as reducing the density of the composition, improving the fluidity and / or processability of the composition. Inorganic filler materials are superior to organic filler materials because they do not damage the compressive strength of the composition. Preferably, part (A) and / or part (B) further comprises at least one filler, which is selected from graphite powder, graphite flakes, carbon black, metal oxides, metal hydroxides, fumed silica, fused silica, aluminum oxide, aluminum hydroxide, calcium oxide, calcium carbonate, magnesium oxide, magnesium carbonate, glass beads, glass microspheres (preferably hollow glass microspheres) and any mixtures and combinations thereof, preferably selected from graphite flakes, carbon black, fused silica, fumed silica, calcium carbonate, glass beads, glass microspheres (preferably hollow glass microspheres) and any mixtures and combinations thereof.

[0061] Preferably, the at least one filler material comprises at least one silica compound. The silica compound may have the effect of making the composition as described herein have improved fluidity, improved processability and increase without sacrificing the mechanical strength or water resistance of the cured adhesive obtained therefrom, etc. In this regard, it is preferred that the at least one silica compound is selected from fused silica, pyrogenic silica, perlite and any combination and mixture thereof. The silica compound as described herein may preferably be used in the form of silica particles. Preferably, the silica particles include pyrogenic silica, preferably hydrophobic pyrogenic silica, fused silica, amorphous silica particles, hollow silica particles, silica gel, calcium silicate and any combination thereof. Exemplary commercial fillers include SHIELDEX AC5 (a synthetic amorphous silica, calcium hydroxide mixture available from WR Grace (Columbia, MD, USA); CAB-O-SIL TS 720 (a hydrophobic fumed silica treated with a polydimethylsiloxane polymer available from Cabot GmbH (Hanau, Germany); AEROSIL VP-R-2935 (a hydrophobic fumed silica available from Degussa (Düsseldorf, Germany); =Glass beads type IV (250-300 microns): amorphous silica (available from 3M Deutschland GmbH, Neuss, Germany); MINSIL SF 20 (available from Minco Inc., 510 Midway, Tennessee, USA); amorphous fused silica; and APYRAL 24 ESF (epoxysilane functionalized (2 wt%) aluminum trihydrate available from Nabaltec GmbH (Schwandorf, Germany). Fused silica is available, for example, from Minco Inc., Midway, USA, under the trade name MINSIL.

[0062] It is further preferred that at least one inorganic filler material in part (B), preferably also part (B) comprises inorganic beads. Inorganic beads or microspheres have the effect of producing a certain control on the gap between two parts adhesively connected by the adhesive composition described herein. In addition, a reduced composition density can also be achieved, which is sometimes desirable. Specifically, microspheres have the ability to reduce the density of the composition, that is, the density of the composition containing microspheres as described is lower than the density of the composition without microspheres. Preferably, the inorganic microspheres are hollow inorganic microspheres because the density of the resulting composition is even further reduced. The microspheres are preferably selected glass bubbles or ceramic bubbles. By way of example, the microspheres can be selected from a variety of materials, including glass, silica, ceramics (including sol-gel derived) or zirconium oxide. The inorganic filler material can have an average particle size of generally less than 500 μm, or between 10 μm and 100 μm. Preferred hollow inorganic microspheres include glass microspheres, which are commercially available, for example, from 3M under the trade names Glassbubbles D32, MICROBUBBLES or Scotchlite D32 / 4500. Similarly, preferred inorganic beads include glass beads, which are also commercially available from 3M. Preferably, part (B) comprises glass beads in an amount ranging from 0.01 wt% to 10 wt%, preferably from 0.1 wt% to 8 wt%, more preferably from 0.2 wt% to 5 wt%, based on the total weight of part (B).

[0063] More preferably, part (B) comprises graphite flakes, preferably expandable graphite flakes, in an amount ranging from 0.1 wt% to 10 wt%, preferably from 0.5 wt% to 8 wt%, and more preferably from 1 wt% to 6 wt%, based on the total weight of part (B). This has the effect of improving the failure mode, i.e., the cohesive failure mode (as opposed to the adhesive failure mode).

[0064] According to a specific aspect of the present disclosure, the second epoxy curing agent used herein is selected from the group consisting of imidazole, imidazole salt, imidazoline or aromatic tertiary amine, and these aromatic tertiary amines include those having the structure of the following formula:

[0065]

[0066] in

[0067] R 1 is H or alkyl, such as for example methyl or ethyl, preferably methyl;

[0068] R 2 For CHNR 5 R 6 ;

[0069] R 3 and R 4may be present or absent independently of each other, and when present, R 3 and R 4 For CHNR 5 R 6 ;

[0070] R 5 and R 6 Each is independently alkyl, preferably CH3 or CH2CH3.

[0071] An exemplary second epoxy curing agent for use herein includes tris-2,4,6-(dimethylaminomethyl)phenol commercially available from Air Products and Chemicals Inc under the trade name ANCAMINE K54.

[0072] Part (A) and / or part (B) (preferably part (A) and part (B)) of the composition as described herein comprises at least one first impact modifier and optionally at least one second impact modifier different from the at least one first impact modifier. This produces the advantage that the cured adhesive bond has improved impact resistance over a wide temperature range. This is particularly important for automotive applications because the requirements for the impact resistance of materials are always increasing for passenger safety. In addition, a certain degree of brittleness of the cured material at low temperatures can be avoided. In this regard, "different from the first impact modifier" refers to that at least one second impact modifier is chemically or physically different from the at least one impact modifier. The at least one first impact modifier and the at least one second impact modifier can be independently selected from the list of butadiene rubber, nitrile rubber and core-shell rubber. Preferably, the at least one first impact modifier is selected from the list of core-shell impact modifiers, preferably selected from core-shell rubber. It is also preferred that the at least one second impact modifier is selected from a core-shell impact modifier and a butadiene rubber impact modifier and any combination and mixture thereof. In a preferred example, the at least one first impact modifier and the at least one second impact modifier may be selected from a core-shell impact modifier, wherein the at least one second core-shell modifier has a different particle size from the at least one first impact modifier and / or the at least one second impact modifier has a different T value from the at least one first impact modifier. G In another preferred example, the at least one first impact modifier is selected from core-shell impact modifiers, and the at least one second impact modifier is selected from butadiene rubber and / or nitrile rubber.

[0073] Exemplary compounds that can be advantageously used as butadiene rubber or nitrile rubber are carboxyl, amine, epoxy, hydroxyl or methacrylate terminated butadiene, butadiene styrene or butadiene acrylonitrile copolymers, preferably amine terminated butadiene styrene or butadiene acrylonitrile copolymers. Such impact modifiers are commercially available, for example, from CVC Thermoset Specialities under the trade names Hypro CTBN, ATBN, ETBN, HTB or VTBNX and from Amerald Materials under the trade name Hycar ATBN, or from Kaneka under the trade name of the MX series, such as MX 257.

[0074] With respect to the core-shell rubber as an impact modifier, any core-shell rubber impact modifier commonly known in the art can be used in the context of the present disclosure. In a typical embodiment, the core-shell rubber impact modifier is a composite material constructed from materials in which the core portion inside and the shell portion outside are different from each other. In this article, the term "different materials" refers to materials in which the composition and / or properties are different from each other, and therefore includes materials using the same type of resin but different molecular weights, etc.

[0075] From the perspective 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 acting as a stress center point, the shell portion inhibits the core-shell rubber from being unfavorably agglomerated, and thus the core-shell impact modifier can be uniformly dispersed in the composition as described herein.

[0076] Examples of core-shell rubber impact modifiers include methyl methacrylate-butadiene copolymers, methyl methacrylate-butadiene-styrene copolymers, methyl methacrylate-acrylonitrile-butadiene-styrene copolymers, methyl methacrylate-acrylic rubber copolymers, methyl methacrylate-acrylic rubber-styrene copolymers, methyl methacrylate-acrylic butadiene rubber copolymers, methyl methacrylate-acrylic butadiene rubber-styrene copolymers, methyl methacrylate-(acrylic silicone IPN rubber) copolymers, etc., but are not limited to those described herein. Methyl methacrylate-butadiene copolymers, methyl methacrylate-butadiene-styrene copolymers, and methyl methacrylate-acrylic butadiene rubber-styrene copolymers can be advantageously used as core-shell toughening agents.

[0077] The core-shell impact modifier is usually in the form of fine particles, and the average value of the primary particle size (weight average particle size) is generally about 0.05 microns or more or about 0.1 microns or more to about 5 microns or less or about 1 micron or less.

[0078] Preferably, the core-shell rubber can be used in a state dispersed in a matrix. Preferably, the matrix is ​​an epoxy resin. From the perspective of good dispersion of the core-shell rubber in the composition as described herein, a matrix having good affinity for the first epoxy resin or the second epoxy resin as described herein is particularly preferred. Examples of the matrix may include epoxy resins (such as bisphenol A, etc.).

[0079] The core-shell impact modifier may be a commercial product provided as a resin modifier, etc., 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 Corporation, in which methyl methacrylate-butadiene-styrene (MBS) is dispersed in bisphenol A glycidyl ether) as a resin, and MC-257 (commercially available from Kaneka Corporation, dispersed in 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), etc. Without wishing to be bound by theory, it is believed that the core-shell polymer rubber particularly advantageously affects the low-temperature adhesion characteristics and impact resistance of the composition described herein.

[0080] Regarding the effect brought about by the presence of at least one first impact modifier in the composition as described herein, it is preferred that the impact modifier is contained in the combined part (A) and part (B) in an amount ranging from 10 wt.% to 60 wt.%, preferably from 15 wt.% to 55 wt.% and more preferably from 20 wt.% to 50 wt.%, based on the total weight of the combined part (A) and part (B).

[0081] The second part (B) of the curable adhesive composition precursor according to the present disclosure comprises at least one first epoxy resin and optionally at least one second epoxy resin. In light of the present detailed description, one skilled in the art will readily identify suitable epoxy resins for use herein.

[0082] The epoxy resin used in this article is not particularly limited. Epoxy resin is a polymer having one or more epoxy functional groups. Typically, but not exclusively, the polymer contains repeating units derived from monomers having epoxy functional groups, but epoxy resins may also include, for example, silicone-based polymers containing epoxy groups, or organic polymer particles coated with epoxy groups or modified with epoxy groups, or particles coated with epoxy-containing polymers or dispersed in polymers or modified by polymers. The epoxy functional groups allow the resin to undergo crosslinking reactions. The epoxy resin may have an average epoxy functionality of at least 1, greater than 1, or at least 2.

[0083] Any epoxy resin generally known to those skilled in the art can be used in the context of the present disclosure. The epoxy resin can be aromatic, aliphatic, alicyclic or a mixture thereof. In typical aspects, the epoxy resin used herein is aromatic. Preferably, the epoxy resin contains a glycidyl or polyglycidyl ether type moiety. Such moieties can be obtained, for example, by the reaction of a hydroxyl functional group (such as but not limited to a dihydric or polyhydric phenol or a fatty alcohol including a polyol) with an epichlorohydrin functional group. As described herein, a dihydric phenol is a phenol containing at least two hydroxyl groups (also referred to as "aromatic" hydroxyl groups) bonded to an aromatic ring of the phenol or, in the case of a polyphenol, at least two hydroxyl groups bonded to an aromatic ring. This means that the hydroxyl groups can be bonded to the same ring of the polyphenol or to different rings of the polyphenol. Therefore, the term "dihydric phenol" is not limited to phenols or polyphenols containing two "aromatic" hydroxyl groups, but also encompasses polyphenols, i.e., compounds having more than two "aromatic" hydroxyl groups.

[0084] Examples of useful dihydric phenols include resorcinol, catechol, hydroquinone, and polyphenols including p,p′-dihydroxybibenzyl, p,p′-dihydroxyphenyl sulfone, p,p′-dihydroxybenzophenone, 2,2′-dihydroxyphenyl sulfone, p,p′-dihydroxybenzophenone, 2,2-dihydroxy-1,1-dinaphthylmethane, and the 2,2′, 2,3′, 2,4′, 3,3′, 3,4′, and 4,4′ isomers of dihydroxydiphenylmethane, dihydroxydiphenyldimethylmethane, dihydroxydiphenylethylmethylmethane, dihydroxydiphenylmethylpropylmethane, dihydroxydiphenylethylphenylmethane, dihydroxydiphenylpropenylphenylmethane, dihydroxydiphenylbutylphenylmethane, dihydroxydiphenyltolylethane, dihydroxydiphenyltolylmethylmethane, dihydroxydiphenyldicyclohexylmethane, and dihydroxydiphenylcyclohexane.

[0085] Preferred epoxy resins include epoxy resins containing glycidyl ethers or polyglycidyl ethers of dihydric or polyhydric phenols (such as but not limited to bisphenol A, bisphenol F and combinations thereof) or epoxy resins composed of glycidyl ethers or polyglycidyl ethers of dihydric or polyhydric phenols. They contain one or more repeating units derived from bisphenol A and / or F. These ethers or these repeating units can be obtained, for example, by polymerization of glycidyl ethers of bisphenol A and / or F with epichlorohydrin. Epoxy resins of the diglycidyl ether type of bisphenol A can be represented by the formula, wherein n represents a repeating unit (when n=0, the following formula represents the diglycidyl ether of bisphenol A):

[0086]

[0087] Typically, epoxy resins are blends of several resins. Therefore, n in the above formula may represent an average value of the blend and may not be an integer, but may include values ​​such as, but not limited to, 0.1 to 2.5.

[0088] Typically, the epoxy resin is a liquid. The epoxy resin may include a solid epoxy resin used in dissolved form or dispersed in, for example, another liquid resin. Preferably, the epoxy resin is a liquid at ambient conditions (23° C., 1 bar). The epoxy resin may contain halogens, preferably bromine atoms, to make them non-flammable.

[0089] Examples of suitable and commercially available epoxy resins include diglycidyl ethers of bisphenol A (available under the trade names EPON 828, EPON 830, EPON 1001, or EPIKOTE 828 from Hexion Specialty Chemicals GmbH, Rosbach, Germany, or under the trade names DER-331 or DER-332 from Dow Chemical Co,); diglycidyl ethers of bisphenol F (e.g., EPICLON 830 from Dainippon Ink and Chemicals, Inc. or DER-354 from Dow Chemical Co, Schwalbach / Ts., Germany); diglycidyl ethers of blends of bisphenol A and bisphenol F (e.g., DER-354 from Momentive Specialty Chemicals, Columbus, USA); Other bisphenol-based epoxy resins are commercially available under the trade name EPILOX (Leuna Epilox GmbH, Leuna, Germany); flame-retardant epoxy resins are commercially available under the trade name DER 580 (a brominated bisphenol-based epoxy resin from Dow Chemical Co.). Cycloaliphatic epoxy resins are commercially available under the trade name EPINOX (Hexion Specialty Chemicals GmbH).

[0090] Preferably, the amount of the at least one first epoxy resin in part (B) and the at least one impact modifier in part (B) together equals an amount in the range of 30 wt % to 80 wt %, preferably 35 wt % to 75 wt %, more preferably 40 wt % to 70 wt %, based on the total weight of part (B). More preferably, the amount of the at least one first epoxy resin in part (B) and the at least one impact modifier in part (B) together equals an amount in the range of 30 wt % to 80 wt %, preferably 35 wt % to 75 wt %, more preferably 40 wt % to 70 wt %, based on the total weight of part (B).

[0091] Part (B) of the curable adhesive composition precursor according to the present disclosure may also include at least one second epoxy resin that is different, ie chemically different, from the first epoxy resin. The chemical difference from the first epoxy resin may result in further differences from the first epoxy resin.

[0092] For example, the at least one second epoxy resin can be a multifunctional epoxy resin, preferably selected from triglycidyl ether, tetraglycidyl ether and pentaglycidyl ether. It may be a single epoxy resin, or it may be a combination of two or more epoxy resins. In a preferred embodiment, the equivalent weight of the trifunctional, tetrafunctional or pentafunctional epoxy resin is about 60 or more, or about 70 or more, or about 80 or more from the perspective of ease of procurement and reaction characteristics, and is about 1000 or less, or about 500 or less, or about 300 or less from the perspective of heat resistance of the cured epoxy adhesive.

[0093] Preferred examples of trifunctional epoxy resins used herein include glycidylamine epoxy resins, glycidylphenol epoxy resins, and the like. Examples of glycidylamine epoxy resins include triglycidylaminophenol epoxy compounds, triglycidylaminocresol epoxy compounds. Examples of glycidylphenol epoxy resins include novolac epoxy compounds, triphenylmethane triglycidyl ether compounds, and the like. Epoxy resins that can be used as the trifunctional (or higher functional) second epoxy resin as described herein can be commercially available from Huntsman under the trade names TACTIX and ARALDITE. It is also preferred that at least one of the at least one second epoxy resin is selected from the group generally known to those skilled in the art as novolac epoxy resins. For example, well-known novolac compounds are phenolic compounds bridged by ortho-ortho, ortho-para and para-para methylene. Examples are reaction products of phenol and formaldehyde. Novolac epoxy resins can be obtained, for example, from the reaction of epichlorohydrin with the phenol-formaldehyde novolac compound. The epoxy novolac compound generally has a polyepoxy functionality as defined above of greater than 1, greater than 2, or even greater than 3. The epoxy novolac resin as described herein may be a liquid or semi-solid. An example of a suitable and commercially available epoxy novolac resin is the epoxy novolac resin available from The Dow Chemical Company under the trade name DEN.

[0094] It is also preferred that at least one second epoxy resin is an epoxy resin comprising an additional multifunctional moiety. A functional moiety is a moiety that can react with other functional moieties such as an epoxy moiety. Therefore, the presence of additional functional moieties in at least one second epoxy resin can enhance reactivity and / or the ability to crosslink with other epoxy resins such as at least one first epoxy resin. This can enhance the hardness, water resistance and / or organic solvent resistance, corrosion resistance, mechanical impact resistance, etc. of the adhesive obtained from the composition as described herein. The reactive moiety as described herein can be a moiety selected from alcohols, amines (particularly secondary amines), thiols, sulfides, etc. Exemplary and preferred epoxy resins modified with reactive moieties can be commercially available from CVC Chemicals under the trade name Epalloy (e.g., Epalloy 7200).

[0095] The use of a combination of a first epoxy resin and a second epoxy resin as described herein can produce a particularly desirable combination of properties of the cured composition, such as high mechanical strength and advantageous properties such as high lap shear strength and high peel strength, even at elevated temperatures. In addition, the combination of the first epoxy resin and the second epoxy resin as described herein can also accelerate the cure rate without sacrificing the mechanical strength of the resulting adhesive.

[0096] Preferably, part (B) contains at least one multifunctional resin in an amount ranging from 5 wt % to 45 wt %, preferably from 10 wt % to 40 wt %, and more preferably from 15 wt % to 35 wt %, based on the total weight of part (B).

[0097] It is also preferred that part (B) of the curable adhesive precursor according to the present disclosure comprises an epoxy reactive diluent. The reactive diluent is an epoxy-containing molecule. There is no particular limitation on the epoxy reactive diluent used herein. Any epoxy reactive diluent commonly known in the art can be used in the context of the present disclosure.

[0098] Without wishing to be bound by theory, it is believed that epoxy-based reactive diluents particularly advantageously affect the flow characteristics of the curable compositions as described herein.

[0099] In a particular aspect of the present disclosure, the epoxy reactive diluent used herein has a saturated or unsaturated cyclic backbone and preferably contains a glycidyl ether as a reactive terminal portion.

[0100] According to a preferred aspect, the epoxy reactive diluent used herein is selected from the group consisting of diglycidyl ether of resorcinol, diglycidyl ether of cyclohexanedimethanol, diglycidyl ether of neopentyl glycol, triglycidyl ether of trimethylolpropane, and any mixture thereof.

[0101] Commercially available reactive diluents useful herein include, for example, "Reactive Diluent 107" (available from Hexion) and the "Epodil" series (available from Air Products and Chemical Inc, Allentown, PA, USA), specifically including EPODIL 746, EPODIL 747, EPODIL 748, and EPODIL 757.

[0102] More preferably, part (A) and / or part (B) further comprises at least one wetting agent and / or at least one reactive diluent. Preferably, the at least one wetting agent is selected from silanes, preferably from epoxy silanes. Preferably, part (B) comprises at least one wetting agent and at least one reactive diluent in an amount in the range of 0.5 wt % to 20 wt %, preferably 1 wt % to 15 wt %, more preferably 2 wt % to 10 wt %, based on the total weight of part (B).

[0103] Part (B) may further comprise at least one viscosity modifier, preferably selected from partially or fully hydrogenated epoxy resins, more preferably selected from hydrogenated bisphenol A and / or bisphenol F diglycidyl ether. Adding partially or fully hydrogenated epoxy resins to part (B) of a curable adhesive precursor as described herein has the effect of reducing the viscosity of part (B) and the curable adhesive composition, respectively. This is particularly advantageous when preparing part (B), mixing part (B) with part (A) and applying the curable composition to a substrate. Therefore, in the context of the present disclosure, partially or fully hydrogenated epoxy resins may be referred to as "viscosity modifiers". Preferably, hydrogenated bisphenol A and / or bisphenol F diglycidyl ether are used. For example, hydrogenated bisphenol A diglycidyl ether resins can be commercially available from Hexion under the trade name "Eponex" such as "Eponex 1510". When present, the viscosity modifier is contained in part (B) of the curable adhesive composition precursor according to the present disclosure in an amount of 0.2 wt % to 20 wt %, preferably 1 wt % to 15 wt %, more preferably 2 wt % to 10 wt %, based on the total weight of part (B).

[0104] Preferably, the volume ratio of part (B) to part (A) is in the range of 10:1 to 1:5, preferably 6:1 to 1:3, more preferably 4:1 to 1:1, and even more preferably about 2:1. This can be achieved by including part (A) and part (B) in an applicator including two separate sleeves and a mixing nozzle well known in the art (i.e., part (A) in one sleeve and part (B) in another sleeve). Therefore, the volume ratio is included in this article. In addition, according to the present invention, storing part (A) and part (B) in two separate tanks and pumping part to the mixing nozzle is also included in this article. It should also be understood that the advantageous effects of the composition of the present disclosure are only realized within these mixing ratios. For example, using a lower amount of part (A) can damage the curing speed of the curable adhesive composition and the tolerance of the adhesive obtained therefrom. It should also be understood that using different ratios within the range as described herein will affect the characteristics of the curable adhesive composition and the curing composition. For example, the viscosity of the curable adhesive composition can be adjusted. In addition, the flexibility of the curing adhesive can be adjusted according to the requirements of the corresponding application.

[0105] The present disclosure also provides the curable adhesive composition obtained by combining part (A) and part (B) of a curable adhesive composition precursor as described herein. As used herein, combination has the meaning that this area is usually used for two-component compositions, i.e., combining two parts and then mixing or mixing and combining in one step. In the mixing nozzles that are well known in the art and commercially used and can be used for this purpose, this is a common situation. The curable adhesive composition is preferably directly prepared before its intended use (i.e., applied on the substrate surface). Due to the characteristics of the composition as described herein, the surface is preferably a metal surface such as a steel plate or a steel part of a vehicle such as a body of a car. After application and subsequent curing according to the adhesive composition of the present disclosure, a strong adhesive bond is obtained between two substrates.

[0106] The curable adhesive exhibits highly desirable properties for applications in the automotive, commercial transportation or electronics industries. Preferably, the curable adhesive composition according to the present disclosure exhibits, after curing, a lap shear strength of at least 11 MPa, preferably at least 12 MPa, and more preferably at least 13 MPa at 80° C. according to DIN EN 1465, and / or a lap shear strength of at least 8 MPa, preferably at least 9 MPa, and more preferably at least 10 MPa at 100° C. according to DIN EN 1465, and / or an impact peel of at least 17 MPa, preferably at least 18 MPa, and more preferably at least 20 MPa at -20° C. according to ISO 11343.

[0107] Furthermore, the present disclosure provides a method for bonding components,

[0108] A method for bonding parts, the method comprising the steps of:

[0109] (a) providing an adhesive as described herein;

[0110] (b) applying the adhesive composition to at least a portion of the surface of the first component;

[0111] (c) applying a second component to the adhesive composition applied to the first component;

[0112] (d) performing a curing step to cure the adhesive composition as described herein to adhesively bond the first component to the second component.

[0113] Preferably, the material of the first component and / or the second component is selected from metal, polymer material, carbon fiber, glass fiber, glass, wood, ceramic material, composite material, preferably selected from metal, polymer material, carbon fiber and composite material. Preferably, the metal is selected from metal, the metal is selected from steel, aluminum, magnesium, titanium, zinc and any combination and alloy thereof, preferably selected from aluminum and steel, and more preferably selected from aluminum and its alloy.

[0114] Preferably, the curing step is carried out at a temperature of 10°C to 40°C, preferably 14°C to 35°C and more preferably 18°C ​​to 30°C, even more preferably at ambient temperature. This has the advantage that no additional heating step is required to achieve full bond strength, saving the time, equipment and energy normally required for curing.

[0115] Due to the excellent applicability of the curable adhesive composition precursor according to the present disclosure and the curable adhesive composition obtained therefrom for bonding parts, while curing under ambient conditions to achieve good bonding performance, the present disclosure also provides the curable adhesive composition and its corresponding precursor for bonding, joining or sealing parts, preferably bonding metal and / or composite parts in manufacturing operations in the automotive industry, electronics industry and / or commercial transportation industry. The metals and parts included in the use as described herein are the same as those disclosed herein in conjunction with the method according to the present disclosure. Preferably, the use as described herein is the body-in-white process, battery housing, and electric vehicle in the automotive industry.

[0116] Example

[0117] The present disclosure is further described, however, it is not intended to be limited thereto. The following examples are provided to illustrate certain embodiments but are not intended to be limiting in any way. Prior to this, some test methods for characterizing materials and their properties will be described. Unless otherwise indicated, all parts and percentages are by weight.

[0118] Example

[0119] Materials used :

[0120]

[0121] Test Method

[0122] Curing rate

[0123] Determine cure rate by measuring lap shear strength as described below (except described curing procedure).Apply sample with the adhesive composition mixed and make it solidify at room temperature.Then test lap shear strength after certain interval.The shear strength that relatively passes over time provides the indication of cure rate, i.e. the comparison of cure rate that different embodiments and comparative example pass over time.

[0124] Lap shear strength according to DIN EN 1465 (published in 2009)

[0125] According to DIN EN 1465, a Zwick Z050 tensile tester (commercially available from Zwick GmbH & Co. KG, Ulm, Germany) was used on a 100 mm x 25 mm x 0.8 mm thick steel sheet coated with 3 g / m 2 The lap shear strength was determined on an aluminum substrate coated with a dry lubricant coated with oil (PL 3802-39S, commercially available from Fuchs Petrolub AG, Germany) at a crosshead speed of 10 mm / min. To prepare the lap shear strength test assembly, the epoxy film to be tested (having a thickness of 0.4 mm) was applied to one end of a first steel strip and covered by a second steel strip, thereby forming a 10 mm lap joint. The lap joint was then clamped together using two binder clips, and the test assembly was placed in an air circulating oven with a minimum baking cycle of 20 min at 160°C and a maximum baking cycle of 45 min at 200°C. Here, the test assembly was heated and cooled using a gradient of 3°C / min. The test assembly was then conditioned for 24 hours under ambient conditions of 23+ / -2°C and 50+ / -%% relative humidity before testing. Prior to testing on a Zwick tensile tester, the test assemblies were placed in an environmental chamber (commercially available from RS Simulatoren, Oberhausen, Germany) and the lap shear strength was measured at room temperature (23°C + / - 2°C). Three samples of each example were measured at three different test temperatures, and the results were then averaged and reported in MPa.

[0126] Impact peeling analysis

[0127] The analysis was carried out according to DIN EN ISO 11343. The substrate was stainless steel with a substrate thickness of 0.8 mm. The sample width was 20 mm. The coating was carried out in the joined state at 35° C. for 24 hours. The curing was carried out at 180° C. for 30 minutes. The test equipment used was an Instron VHS 50 / 2 with a test speed of 2 m / s.

[0128] Preparation of Part A and Part B

[0129] Part (A) and Part (B) were prepared using the ingredients listed in Table 1 and Table 2 according to the procedure listed below.

[0130] Element Example 1 Amine adduct 74 Multifunctional aliphatic amines 5 Curing accelerator 10 filler 11

[0131] Table 1: Composition of part (A). All ratios are given in wt %. .

[0132] Raw materials (B) Example 1 Toughened epoxy resin 60 Multifunctional epoxy resin 20 Flexible epoxy resin 7 Graphite flakes 2 Wetting agents and diluents 5 Glass beads 1 filler 5

[0133] Table 2: Composition of part (B). All ratios are given in wt %. .

[0134] Part A :

[0135] Part (A) was prepared by adding calcium nitrate / ammonium nitrate to the primary curing agent and mixing in a high speed mixer (3000 U / min) for 2 minutes. After the calcium nitrate / ammonium nitrate was fully dispersed, the filler was then added and mixing continued for another 2 minutes. Ancamine K54 was then added and mixed. In the final step, part (A) was degassed under vacuum for 2 minutes while mixing. The degassed part A was then filled into one side of a 200 mL Dual Pac cartridge.

[0136] Part B :

[0137] The base resin was made by mixing the toughened epoxy resin with the multifunctional epoxy resin and the flexible epoxy resin in a high speed mixer for 1 minute. Fillers, graphite flakes, wetting agents and diluents were then added stepwise and mixed several times until a uniform mixture was obtained. The mixture was then degassed under vacuum for 2 minutes while mixing. The degassed Part B was filled into the other side of the Dual Pac cartridge. The mixing ratio of Part (A) to Part (B) by volume was 1:2.

[0138] The adhesive properties of Example 1 were then evaluated. In particular, the impact peel and lap shear strength at low temperatures were determined. As comparative examples, commercially available adhesives, namely Comparative Example 1 (3MSA 9822) and Comparative Example 2 (SA9844), were used. The results are summarized in Table 3.

[0139]

[0140] Table 3: Test results .

Claims

1. A curable adhesive composition precursor, comprising: The first part (A), the first part (A) comprising (i) at least one first epoxy curing agent; (ii) at least one first curing aid, the at least one first curing aid comprising at least one ammonium salt; The second part (B), the second part (B) comprises (i) at least one epoxy resin; and (ii) Optionally, at least one first impact modifier. 2 . The curable adhesive composition precursor according to claim 1 , wherein the at least one first epoxy curing agent is selected from multifunctional amine-based epoxy curing agents.

3. The curable adhesive composition precursor according to claim 1 or claim 2, wherein the curable composition precursor further comprises at least one second epoxy curing agent different from the at least one first epoxy curing agent, the at least one second epoxy curing agent is preferably selected from diamines, polyamidoamines, alkylphenol amides, alkylphenol amines, epoxy-amine adducts, polyetheramines, alicyclic amines and any combination and mixture thereof, more preferably selected from polyetheramine-epoxy adducts.

4. The curable adhesive composition precursor according to any one of the preceding claims, wherein the at least one ammonium salt of the at least one first curing aid comprises at least one organic or inorganic anion.

5. The curable adhesive composition precursor according to any one of the preceding claims, wherein the at least one ammonium salt of the at least one first curing aid is an ammonium salt according to Formula 1 NR 1 R 2 R 3 R 4 X-Form 1 in R 1 , R 2 , R 3 and R 4 Each of the may be the same or different and is independently selected from H, linear or branched alkyl or alkoxy, preferably selected from H and linear or branched alkyl; X is selected from chloride, bromide, nitrate, sulfate, triflate, preferably selected from nitrate and triflate, more preferably nitrate.

6. The curable binder composition precursor according to any one of the preceding claims, wherein the at least one first curing aid further comprises at least one metal salt, preferably wherein the at least one metal salt comprises at least one anion selected from chloride, bromide, nitrate, sulfate, thiosulfate, triflate, phosphate and any combination and mixture thereof, preferably selected from nitrate and triflate, and more preferably nitrate.

7. The curable adhesive composition precursor of claim 6, wherein the at least one first curing aid comprises calcium nitrate and ammonium nitrate.

8. A curable adhesive composition precursor according to any one of the preceding claims, wherein part (A) further comprises at least one second curing aid different from the at least one first curing aid, the at least one second curing aid being preferably selected from the group consisting of imidazoles, imidazolium salts, imidazolines or aromatic tertiary amines.

9. The curable adhesive composition precursor according to claim 8, wherein the at least one second curing aid different from the at least one first curing aid is selected from aromatic tertiary amines, including aromatic tertiary amines having the following structure: in R 1 is H or alkyl, such as for example methyl or ethyl, preferably methyl; R 2 For CHNR 5 R 6 ; R 3 and R 4 can be present or absent independently of each other, and when present, R 3 and R 4 For CHNR 5 R 6 ; R 5 and R 6 Each is independently alkyl, preferably CH3 or CH2CH3.

10. A curable adhesive composition according to any one of the preceding claims, wherein part (B) further comprises at least one multifunctional epoxy resin, preferably selected from triglycidyl ether, tetraglycidyl ether and pentaglycidyl ether.

11. A curable adhesive composition precursor according to any one of the preceding claims, wherein part (A) and / or part (B), preferably part A and part (B), further comprises at least one impact modifier.

12. A curable adhesive composition precursor according to any one of the preceding claims, wherein part (A) and / or part (B) further comprises at least one filler, the at least one filler being selected from graphite powder, graphite flakes, carbon black, metal oxides, metal hydroxides, fumed silica, fused silica, aluminum oxide, aluminum hydroxide, calcium oxide, calcium carbonate, magnesium oxide, magnesium carbonate, glass beads, glass microspheres, preferably hollow glass microspheres, and any mixtures and combinations thereof, preferably selected from graphite flakes, carbon black, fused silica, fumed silica, calcium carbonate, glass beads, glass microspheres, preferably hollow glass microspheres, and any mixtures and combinations thereof.

13. A curable adhesive composition obtained by combining part (A) and part (B) of the curable adhesive precursor according to any one of the preceding claims.

14. A method for bonding parts, the method comprising the steps of: (a) providing the adhesive composition according to claim 13; (b) applying the adhesive composition to at least a portion of the surface of the first component; (c) applying a second component to the adhesive composition applied to the first component; (d) performing a curing step to cure the adhesive composition so as to adhesively bond the first member and the second member.

15. Use of a curable adhesive composition precursor according to any one of claims 1 to 12 or a curable adhesive composition according to claim 13 for bonding, joining and / or sealing parts, preferably bonding metal and / or composite parts in manufacturing operations in the automotive industry and / or commercial transportation industry.

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