Pumpable one-component adhesive composition

[0001] Priority is claimed of European patent application no. 22 190 696.9 that was filed on August 17, 2023.

[0002] The invention relates to a curable one-component adhesive composition comprising (a) liquid epoxy resin; (b) latent epoxy curing agent; (c) silica; and (d) metal oxide; wherein the weight content of the liquid epoxy resin is at least 20 wt.-%, based on all liquid epoxy resin that is contained in the composition and relative to the total weight of the one-component adhesive composition.

[0003] Epoxy paste adhesives are extensively used in various technologies, e.g. in vehicle construction. Epoxy paste adhesives may contain various additives such as curing agents, blowing agents, tougheners, impact modifiers, fillers, and the like. These epoxy paste adhesives are typically applied onto a substrate, e g. robotically, in the uncured state and at a later stage of manufacture activated, e.g. heated, to effect curing.

[0004] Epoxy paste adhesives need to exhibit a good rheological profile to allow for easy handling and applicability, e.g. by means of a robot. Good pumpability at low temperatures is particularly desirable. Epoxy paste adhesives should also be designed to endure relatively high temperatures.

[0005] Prior to curing, the epoxy paste adhesives need to withstand various conditions they are typically exposed to. Once an epoxy paste adhesive has been applied onto a substrate, e.g. a metal panel of a vehicle, the epoxy paste adhesive should sufficiently adhere to the surface of the substrate and not sag.

[0006] During further processing, e g. after possible further steps of construction have been carried out, the entire vehicle assembly is typically subjected to a series of sprays and baths serving various purposes. Some treatments remove oil or dirt, other treatments provide corrosion resistance by applying protective coatings from liquid baths. During these processing steps, the thus applied epoxy paste adhesive is still present in its uncured state and needs to remain on the substrate. It can be difficult to achieve satisfactory properties, particularly when the substrate surface to which the epoxy paste adhesive has been applied is exposed to washing or dipping operations. If the epoxy paste adhesive failed to withstand these conditions, the epoxy paste adhesive would “wash-out” the vehicle assembly and this is to be avoided. It must be ensured that after such washing or dipping operation, adhesive bond quality is not degraded and that the washing or dipping liquid is not contaminated with constituents of the epoxy paste adhesive.

[0007] EP 0 899 300 A2 relates to an epoxy resin type composition comprising an epoxy resin, 100 parts (by weight); a powdery methacrylate type polymer, 2 to 45 parts; a thermally active hardening agent, 1 to 20 parts; a thermally decomposable foaming agent, 0.5 to 20 parts; and a mixture containing an inorganic salt, with a predetermined aspect ratio, and a granular inorganic salt, the mixture amounting to 50 to 200 parts.

[0008] CN 110 885 656 A relates to an automotive amorphous sealant and a preparation method thereof, wherein the automotive amorphous sealant comprises the following raw materials in percentage by weight: 20-30% of butadiene rubber, 20-30% of epoxy resin, 15-25% of inorganic flame retardant, 15- 25% of wollastonite powder, 1.5-3% of cross-linking agent, 1-3% of cross-linking assistant and 2-4% of epoxy assistant.

[0009] US 2004 266899 Al relates to an expandable thermosettable compositions containing at least one epoxy resin, at least one finely divided thermoplastic polymer powder, at least one blowing agent, at least one curing agent, and at least one filler are suitable for the production of thermosetting laminated bodies with a tacky surface.

[0010] US 2006 188726 Al relates to compositions containing at least one liquid epoxy resin, at least one solid epoxy resin, at least one propellant, at least one curing agent and at least one mica-containing filler produce expandable, thermally curable binder systems which may be used without the addition of hollow glass beads for the production of stiffening and reinforcing laminates and for the production of stiffening and reinforcing moldings.

[0011] US 2009 0065143 Al relates to a two-component epoxy adhesive composition comprising a) a first component comprising a first epoxy resin and a second epoxy resin, the second epoxy resin being flexibilized by an elastomer, and b) a second component comprising at least one amine compound with one or more primary and/or secondary amino groups, said amine compound having a molecular weight of less than 450 g/mol. The mixing of the two components a) and b) results in a wash-out resistant composition. Said wash out resistant composition results upon heat-curing in a crash stable structural adhesive.

[0012] US 2010 0272908 Al relates to compositions useful as adhesives and more particularly to the preparation of heat-curable epoxy-based adhesive compositions that are resistant to being washed out substrate surfaces prior to being cured.

[0013] US 2011 036497 Al relates to compositions useful as adhesives and more particularly to the preparation of heat-curable epoxy-based adhesive compositions that are capable of being easily pumped under high shear at temperatures around room temperature but are resistant to being washed out substrate surfaces prior to being cured.

[0014] US 2012 0207925 Al relates to a two-component premix for preparing a heat-expandable and heat-curable epoxy-based material, which comprises an isocyanate, a diol or polyol, an epoxy prepolymer, a heat-activatable hardener for epoxy prepolymers, and a heat-activatable blowing agent. [0015] US 2013 0149531 Al relates to an adhesive material and articles incorporating the same. The adhesive material includes a liquid epoxy resin and rubber, a solid epoxy resin and rubber, one or more curing agents, and a filler.

[0016] US 2016 0244603 Al relates to a curable resin composition containing 1 to 100 parts by mass of a polymer fine particle (B) relative to 100 parts by mass of an epoxy resin (A), wherein the polymer fine particle has a core-shell structure, the core layer of the polymer fine particle is diene rubber, the content of the epoxy group of the polymer fine particle (B) is 0.01 to 0.2 mmol/g.

[0017] US 2018 037708 Al relates to pumpable thermally foaming filler compositions based on combinations of a liquid epoxy resin and a polyvinyl chloride resin and/or an acrylic resin powder.

[0018] US 2018/258329 Al relates to one-component toughened epoxy structural adhesives that contain fibrous mineral fillers that have an aspect ratio of >6. The presence of the fibrous filler is said to lead to increased elastic modulus while having little if any adverse effect on other properties such as dynamic impact peel resistance.

[0019] US 2020 0095418 Al relates to a curable composition, which includes a diluent , an epoxy functionalized resin derived from a nutshell oil, an epoxy - rubber copolymer adduct, and a curing agent.

[0020] US 2020 0231849 Al relates to an epoxy-based crash durable adhesive composition that is pumpable at a temperature of 15° C or greater; and exhibits an increase in wash-out resistance.

[0021] WO 2020/097050 Al relates to a reinforcing patch for stiffening vehicle panels. The reinforcing patch may be fabric free (e.g., free of any reinforcing layer). The reinforcing patch may be cut into small shapes, complex shapes, or both. The stiffening material may be free of a mesh or a fabric, which may allow the reinforcing patch material to be easily produced and easily reprocessed. The reinforcing patch may include one or more reinforcing particulates in combination with one or more discontinuous fiber components to obtain stiffness comparable to traditional patches which include a mesh/fabric layer.

[0022] US 2020/231849 Al relates to an epoxy-based crash durable adhesive composition including: (I) a liquid resin system comprising: (a) at least one epoxy resin; and (b) at least one toughener; wherein the viscosity of the liquid resin system is less than about 800 Pa s at a temperature of 15 °C; and wherein the viscosity of the liquid resin system is greater than about 5 Pa s at a temperature of 60°C; (II) a solid material comprising: (c) at least one hydrophobic fumed silica, wherein the fumed silica is present in the adhesive composition at a concentration of greater than 5 weight percent; and (III) a curative material comprising: (d) at least one latent heat-activated curing agent; wherein the rheology of the epoxy-based crash durable adhesive composition is such that the adhesive composition is pumpable at a temperature of 15 °C or greater. The epoxy-based crash durable adhesive composition is said to exhibit an increase in wash-off resistance. [0023] The epoxy paste adhesives that are known from the prior art are not satisfactory in every respect Several known epoxy paste adhesives do not provide an acceptable wash-out resistance and are not pumpable at low temperatures.

[0024] It is an object of the invention to provide pumpable curable one-component adhesive compositions that have advantages compared to the curable one-component adhesive compositions of the prior art. The pumpable curable one-component adhesive compositions should be wash-out resistant and ageing resistant. The pumpable curable one-component adhesive compositions should provide excellent adhesive properties after curing and should be processable by conventional equipment. Pumpability should allow for application to substrates by means of conventional pumping and application devices such as robotic dispensers.

[0025] This object has been achieved by the subject-matter of the patent claims.

[0026] It has been surprisingly found that silica, preferably fumed silica, and metal oxide, preferably calcium oxide, provide pumpable curable one-component adhesive compositions with advantageous properties, especially in combination with one or more silicates, preferably inosilicates and/or phyllosilicates. Wash-out resistance as well as aging resistance in terms of lap shear resistance in a humid cataplasma test can be significantly improved.

[0027] A first aspect of the invention relates to a curable one-component adhesive composition comprising

(a) liquid epoxy resin, preferably comprising or essentially consisting of liquid glycidyl ether of a bisphenol (e.g. DGEBA, DGEBF, and the like), liquid epoxy novolac resin, or combinations thereof;

(b) latent epoxy curing agent; preferably dicyandiamide;

(c) silica; preferably fumed silica; more preferably polydimethylsiloxane treated fumed silica;

(d) metal oxide; preferably calcium oxide (CaO);

(e) optionally, phyllosilicate; preferably clay (e.g. talc) and/or organophilic phyllosilicate; and

(f) optionally, inosilicate; preferably wollastonite; wherein the weight content of the liquid epoxy resin is at least 20 wt.-%, preferably at least 30 wt.-%, more preferably at least 40 wt.-%, still more preferably at least 50 wt.-%, based on all liquid epoxy resin that is contained in the composition and relative to the total weight of the one-component adhesive composition.

[0028] Components (e) and (f) of the composition according to the invention are independently of one another optional, whereas components (a), (b), (c) and (d) are mandatory. Besides components (a) through (d), the composition according to the invention may contain additional components or ingredients. Besides optional components (e) and (f), additional optional components (g) through (p) are further specified below.

[0029] The composition according to the invention is a one-component composition. Thus, the composition according to the invention is preferably a ready-to use composition that already contains all ingredients that are needed for the desired purpose. In particular, prior to use, the composition according to the invention does preferably not require any addition of further additives nor admixture with other compositions.

[0030] The composition according to the invention is curable, i.e. is capable of autonomously undergoing a curing reaction, typically by cross-linking, after proper stimulation, preferably by heating to elevated temperature. Partial curing or curing (i.e. full curing) may be effected by reacting one or more ingredients that are contained in the composition with one another thereby forming covalent bonds. Activation temperatures to induce curing are typically within the range of from 80 to 210°C, preferably 120 to 160°C. Activation temperatures may be adjusted by conventional means that are known to the skilled person. Latent curing agents are known that are activated at different temperatures and react with epoxy resins, preferably glycidyl ethers of bisphenols, epoxy novolac resins, and the like. Activation temperatures may be further modified by curing accelerators that typically lower activation temperatures.

[0031] The invention provides fast-curing one-component adhesives.

[0032] In preferred embodiments, the list of optional components that may be contained in the composition according to the invention is extended from (e) and (f) to (g) through (p). Preferably, optionally, the curable one-component adhesive composition additionally comprises one or more of the following components (e) to (p):

(d) metal oxide; preferably calcium oxide (CaO);

(e) phyllosilicate; preferably clay (e.g. talc) and/or organophilic phyllosilicate; more preferably zinc strontium phosphosilicate;

(f) inosilicate; preferably wollastonite;

(g) reactive diluent; preferably glycidyl ether epoxy resin of cashew nutshell liquid;

(h) additional curable epoxy resin; preferably semi-solid curable epoxy resin;

(i) fibers; preferably discontinuous fibers; preferably glass fibers;

(j) polyhydroxy carboxylic acid ester;

(k) polyamide;

(l) blowing agent; preferably chemical blowing agent; more preferably azodicarbonamide;

(m) impact modifier; (n) toughening agent and/or flexibilizer;

(o) phenoxy resin; preferably a solid phenoxy resin; more preferably a solid phenoxy resin which is a copolymer of bisphenol A and epichlorohydrin; and/or

(p) curing accelerator.

[0033] Components (e) through (p) of the composition according to the invention are independently of one another optional, whereas components (a), (b), (c) and (d) are mandatory.

[0034] In preferred embodiments, the composition essentially consists of components (a), (b), (c), and (d), and optionally one or more of components (e) to (p).

[0035] In preferred embodiments, the composition comprises or essentially consists of components (a),

(b), (c), (d), and (e); (a), (b), (c), (d), and (f); (a), (b), (c), (d), and (g); (a), (b), (c), (d), and (h); (a), (b),

(c), (d), and (i); (a), (b), (c), (d), and (j); (a), (b), (c), (d), and (k); (a), (b), (c), (d), and (1); (a), (b), (c),

(d), and (m); (a), (b), (c), (d), and (n); (a), (b), (c), (d), and (o); or (a), (b), (c), (d), and (p).

[0036] In preferred embodiments, the composition comprises or essentially consists of components (a),

(b), (c), (d), (e), and (f); (a), (b), (c), (d), (e), and (g); (a), (b), (c), (d), (e), and (h); (a), (b), (c), (d), (e), and (i); (a), (b), (c), (d), (e), and (j); (a), (b), (c), (d), (e), and (k); (a), (b), (c), (d), (e), and (1); (a), (b),

(c), (d), (e), and (m); (a), (b), (c), (d), (e), and (n); (a), (b), (c), (d), (e), and (o); or (a), (b), (c), (d), (e), and (p); (a), (b), (c), (d), (f), and (g); (a), (b), (c), (d), (f), and (h); (a), (b), (c), (d), (f), and (i); (a), (b),

(c), (d), (f), and (j); (a), (b), (c), (d), (f), and (k); (a), (b), (c), (d), (f), and (1); (a), (b), (c), (d), (f), and

(m); (a), (b), (c), (d), (f), and (n); (a), (b), (c), (d), (f), and (o); or (a), (b), (c), (d), (f), and (p); (a), (b),

(c), (d), (g), and (h); (a), (b), (c), (d), (g), and (i); (a), (b), (c), (d), (g), and (j); (a), (b), (c), (d), (g), and (k); (a), (b), (c), (d), (g), and (1); (a), (b), (c), (d), (g), and (m); (a), (b), (c), (d), (g), and (n); (a), (b), (c),

(d), (g), and (o); (a), (b), (c), (d), (g), and (p); (a), (b), (c), (d), (h), and (i); (a), (b), (c), (d), (h), and (j);

(a), (b), (c), (d), (h), and (k); (a), (b), (c), (d), (h), and (1); (a), (b), (c), (d), (h), and (m); (a), (b), (c), (d), (h), and (n); (a), (b), (c), (d), (h), and (o); (a), (b), (c), (d), (h), and (p); (a), (b), (c), (d), (i), and (j); (a),

(b), (c), (d), (i), and (k); (a), (b), (c), (d), (i), and (1); (a), (b), (c), (d), (i), and (m); (a), (b), (c), (d), (i), and (n); (a), (b), (c), (d), (i), and (o); (a), (b), (c), (d), (i), and (p); (a), (b), (c), (d), (j), and (k); (a), (b),

(c), (d), (j), and (1); (a), (b), (c), (d), (j), and (m); (a), (b), (c), (d), (j), and (n); (a), (b), (c), (d), (j), and

(o); (a), (b), (c), (d), (j), and (p); (a), (b), (c), (d), (k), and (1); (a), (b), (c), (d), (k), and (m); (a), (b), (c),

(d), (k), and (n); (a), (b), (c), (d), (k), and (o); (a), (b), (c), (d), (k), and (p); (a), (b), (c), (d), (1), and (m);

(a), (b), (c), (d), (1), and (n); (a), (b), (c), (d), (1), and (o); (a), (b), (c), (d), (1), and (p); (a), (b), (c), (d),

(m), and (n); (a), (b), (c), (d), (m), and (o); (a), (b), (c), (d), (m), and (p); (a), (b), (c), (d), (n), and (o); or (a), (b), (c), (d), (n), and (p).

[0037] Besides components (a) through (p), the composition according to the invention may contain additional ingredients. [0038] Unless expressly stated otherwise, all percentages are weight percentages and are relative to the total weight of the curable one-component adhesive composition.

[0039] Unless expressly stated otherwise, any norms such as EN ISO, ASTM and the like are in the official version that is valid on July 1, 2022.

[0040] The expression "essentially consists of' means a content of at least 95 wt.-%, preferably at least 99 wt.-%, relative to the total weight of the component to which the definition refers.

[0041] The one-component adhesive composition according to the invention comprises (a) liquid epoxy resin, preferably comprising or essentially consisting of liquid epoxy novolac resin. The liquid epoxy resin is preferably a room temperature liquid epoxy resin, i.e. is a liquid at room temperature (25°C).

[0042] Preferably, the weight content of the liquid epoxy resin is at least 30 wt.-%, based on all liquid epoxy resin that is contained in the composition and relative to the total weight of the one-component adhesive composition.

[0043] In preferred embodiments, the liquid epoxy resin comprises or essentially consists of liquid epoxy novolac resin.

[0044] In other preferred embodiments, the liquid epoxy resin comprises or essentially consists of liquid bisphenol diglycidylether resin.

[0045] In still other preferred embodiments, the liquid epoxy resin comprises or essentially consists of a mixture of liquid epoxy novolac resin and liquid bisphenol diglycidylether resin.

[0046] Preferably, the content of liquid epoxy novolac resin is greater than the content of liquid bisphenol diglycidylether resin.

[0047] Preferably, the content of liquid bisphenol diglycidylether resin is greater than the content of liquid epoxy novolac resin.

[0048] Preferably, the content of liquid epoxy novolac resin is equal to the content of liquid bisphenol diglycidylether resin.

[0049] Preferably, the liquid epoxy novolac resin is selected from novolac resins of o-cresol novolac type, phenol novolac type, BPA-novolac type, DCPD type, xylok type, and multi-functional type; preferably phenol novolac type, i.e. a liquid epoxy phenol novolac resin.

[0050] Epoxy phenol novolac (EPN) resins are epoxy resins where the epoxide functional group is attached to the phenolic oxygen of a phenolic novolac. A single EPN polymer contains many epoxide groups, making the molecule multifunctional. Suitable liquid epoxy phenol novolac (EPN) resins are known to the skilled person and commercially available, e.g. under the tradenames D.E.N.® 424, D E N ® 425, D E N ® 426 (Olin), Araldite® EPN 9820, Araldite® EPN 9850 (Huntsman), Epalloy® 8220, Epalloy® 8250 (Huntsman), and the like.

[0051] Preferably, the liquid bisphenol diglycidylether resin is selected from diglycidylether resin of bisphenol A or diglycidylether resin of bisphenol F.

[0052] Bisphenol diglycidylether resins are epoxy resins where the epoxide functional group is attached to the phenolic oxygen of a bisphenol. Suitable liquid bisphenol diglycidylether resins are known to the skilled person and commercially available, e.g. under the tradename D.E.R. ® 301, D.E.R.® 317, D.E.R.® 321, D.E.R.® 322, D.E.R.® 331, D.E.R.® 332, D.E.R.® 336 (Olin), Epalloy® 7200 (Huntsman), and the like.

[0053] Liquid epoxy resins are typically distinguished from semi-solid epoxy resins and from other epoxy resins. Viscosities of liquid epoxy resins are typically determined at 25°C, whereas viscosities of semi-solid epoxy resins are typically determined either at higher temperatures (52°C or 55°C) or in solutions in suitable solvents.

[0054] Preferably, the liquid epoxy resin, preferably comprising or essentially consisting of liquid epoxy novolac resin, more preferably liquid epoxy phenol novolac resin, has an epoxy equivalent weight within the range of from 145 to 200 g/eq, preferably from 160 to 185 g/eq, and more preferably from 165 to 178 g/eq, determined according to ASTM D1652.

[0055] Preferably, the liquid epoxy resin, preferably comprising or essentially consisting of liquid epoxy novolac resin, more preferably liquid epoxy phenol novolac resin, has a viscosity at 25°C of at most 70 Pa s, preferably at most 50 Pa s, more preferably at most 30 Pa s, determined according to ASTM D2196.

[0056] Preferably, the liquid epoxy resin, preferably comprising or essentially consisting of liquid epoxy novolac resin, more preferably liquid epoxy phenol novolac resin, has a viscosity at 25°C within the range of from 14 to 32 Pa s, preferably from 16 to 30 Pa s, more preferably from 18 to 28 Pa s, determined according to ASTM D2196.

[0057] Preferably, the liquid epoxy resin, preferably comprising or essentially consisting of liquid epoxy novolac resin, more preferably liquid epoxy phenol novolac resin, has an epoxy functionality within the range of from 1.3 to 3.9, preferably from 1.7 to 3.5, more preferably from 2.1 to 3.1.

[0058] Preferably, the weight content of the liquid epoxy resin is at least 32 wt.-%, preferably at least 34 wt.-%, more preferably at least 36 wt.-%, still more preferably at least 38 wt.-%, and yet more preferably at least 40 wt.-%, based on all liquid epoxy resin that is contained in the composition and relative to the total weight of the one-component adhesive composition.

[0059] Preferably, the weight content of the liquid epoxy resin is at most 74 wt.-%, preferably at most 70 wt.-%, more preferably at most 66 wt.-%, still more preferably at most 62 wt.-%, yet more preferably at most 58 wt even more preferably at most 52 wt.-%, most preferably at most 48 wt.-%, and in particular at most 44 wt.-%, based on all liquid epoxy resin that is contained in the composition and relative to the total weight of the one-component adhesive composition.

[0060] Preferably, the weight content of the liquid epoxy resin is within the range of 40±20 wt.-%, preferably 40±10 wt.-%, based on all liquid epoxy resin that is contained in the composition and relative to the total weight of the one-component adhesive composition.

[0061] The one-component adhesive composition according to the invention comprises (b) latent epoxy curing agent. For the purpose of the specification, a latent epoxy curing agent does not spontaneously react with the epoxy resin in a curing reaction under ambient conditions (room temperature, 23°C), but requires a stimulus in order to induce curing, typically elevated temperature, preferably at least 80°C, more preferably at least 120°C.

[0062] Preferably, the latent epoxy curing agent is selected from the group consisting of dicyandiamide, aliphatic or aromatic amines or their respective adducts, amidoamines, polyamides, cycloaliphatic amines, anhydrides, polycarboxylic polyesters, isocyanates, phenol-based resins (preferably selected from phenol or cresol novolac resins, copolymers of phenol terpene, polyvinyl phenol, or bisphenol A formaldehyde copolymers, bishydroxyphenyl alkanes), modified and unmodified polyamines or polyamides (preferably selected from triethylenetetramine, diethylenetriamine tetraethylenepentamine, and cyanoguanidine); preferably dicyandiamide. Suitable latent epoxy curing agents such as dicynadiamide are known to the skilled person and commercially available, e.g. under the tradename Dyhard® 100S.

[0063] In a particularly preferred embodiment, the latent epoxy curing agent is dicyanamide.

[0064] Preferably, the weight content of the latent epoxy curing agent is at least 1.4 wt.-%, preferably at least 1.6 wt.-%, more preferably at least 1.8 wt.-%, still more preferably at least 2.0 wt.-%, yet more preferably at least 2.2 wt.-%, even more preferably at least 2.4 wt.-%, most preferably at least 2.6 wt.- %, and in particular at least 2.8 wt.-%, relative to the total weight of the one-component adhesive composition.

[0065] Preferably, the weight content of the latent epoxy curing agent is at most 4.5 wt.-%, preferably at most 4.0 wt.-%, more preferably at most 3.8 wt.-%, still more preferably at most 3.6 wt.-%, yet more preferably at most 3.4 wt.-%, even more preferably at most 3.2 wt.-%, most preferably at most 3.0 wt- %, and in particular at most 2.8 wt.-%, relative to the total weight of the one-component adhesive composition.

[0066] Preferably, the weight content of the latent epoxy curing agent is within the range of 2.8±1.5 wt.-%, preferably 2.8±0.5 wt.-%, relative to the total weight of the one-component adhesive composition.

[0067] The one-component adhesive composition according to the invention comprises (c) silica. [0068] Preferably, the silica is fumed silica, fused silica, silica gel, or quartz; preferably fumed silica; more preferably surface treated fumed silica; still more preferably hydrophobic fumed silica; yet more preferably polydimethylsiloxane treated fumed silica. Suitable silica such as fumed silica is known to the skilled person and commercially available, e.g. under the tradenames Aerosil®, Aerodisp®, Cab-O- Sil Ultrabond® 5760, Cab-O-Sil Ultrabond® 5780, Wacker® HDK, Aeroperl®, and the like.

[0069] Preferably, the silica has the form of particles, flakes, platelets, rods, needles, and/or rectangles.

[0070] Preferably, the total weight content of the silica is least 1.0 wt-%, preferably at least 1.5 wt-%, more preferably at least 2.0 wt-%, still more preferably at least 2.5 wt-%, yet more preferably at least 3.0 wt-%, even more preferably at least 3.5 wt-%, most preferably at least 4.0 wt-%, and in particular at least 4.5 wt-%, relative to the total weight of the one-component adhesive composition.

[0071] Preferably, the total weight content of the silica is at most 19 wt-%, preferably at most 17 wt- %, more preferably at most 15 wt-%, still more preferably at most 13 wt-%, yet more preferably at most 11 wt-%, even more preferably at most 9.0 wt-%, most preferably at most 7.0 wt-%, and in particular at most 5.0 wt.-%, relative to the total weight of the one-component adhesive composition.

[0072] Preferably, the total weight content of the silica is within the range of 5.0±3.0 wt.-%, preferably 5.0±2.0 wt.-%, relative to the total weight of the one-component adhesive composition.

[0073] The one-component adhesive composition according to the invention comprises (d) metal oxide.

[0074] Preferably, the metal oxide is selected from the group consisting of calcium oxide (CaO), magnesium oxide (MgO), barium oxide (BaO), potassium oxide (K ₂ O), lithium oxide (Li ₂ O), sodium oxide (Na ₂ O), and mixtures thereof; preferably CaO. Suitable metal oxides such as CaO are known to the skilled person and are commercially available, e.g. under the tradename Innovox® FG.

[0075] Preferably, the metal oxide has the form of particles, flakes, platelets, rods, needles, and/or rectangles.

[0076] Preferably, the weight content of the metal oxide is at least 1.0 wt.-%, preferably at least 2.0 wt-%, more preferably at least 3.0 wt-%, still more preferably at least 4.0 wt-%, yet more preferably at least 5.0 wt-%, even more preferably at least 6.0 wt.-%, most preferably at least 7.0 wt-%, and in particular at least 8.0 wt-%, relative to the total weight of the one-component adhesive composition.

[0077] Preferably, the weight content of the metal oxide is at most 20 wt.-%, preferably at most 18 wt- %, more preferably at most 16 wt-%, still more preferably at most 14 wt-%, yet more preferably at most 12 wt-%, even more preferably at most 10 wt-%, most preferably at most 8.0 wt-%, and in particular at most 6.0 wt-%, relative to the total weight of the one-component adhesive composition

[0078] Preferably, the weight content ofthe metal oxide is within the range of 5.0±4.0 wt-%, preferably 5.0±2.0 wt.-%, relative to the total weight of the one-component adhesive composition. [0079] The one-component adhesive composition according to the invention optionally comprises (e) phyllosilicate. As already mentioned above, phyllosilicates form sheets. Preferred phyllosilicates according to the invention are selected from the serpentine subgroup, clay minerals, and the mica group, in either case preferably in organically modified form. Suitable phyllosilicates are known to the skilled person and are commercially available, e.g. under the tradename Garamite® 1958, Halox® SZP 391, Halox® SW-111, and the like.

[0080] Preferably, the phyllosilicate has the form of particles, flakes, platelets, rods, needles, and/or rectangles.

[0081] Preferably, the phyllosilicate comprises or essentially consists of one or more clay minerals, preferably talc.

[0082] Preferably, the phyllosilicate comprises or essentially consists of organically modified phyllosilicate; preferably organophilic phyllosilicate.

[0083] Preferably, the phyllosilicate comprises or essentially consists of phosphosilicate; preferably zinc phosphosilicate; more preferably organically modified zinc phosphosilicate; still more preferably strontium zinc phosphosilicate.

[0084] Preferably, the total weight content of the phyllosilicate is at least 0.5 wt.-%, preferably at least 1.0 wt.-%, more preferably at least 1.5 wt.-%, still more preferably at least 2.0 wt.-%, yet more preferably at least 2.5 wt.-%, even more preferably at least 3.0 wt.-%, most preferably at least 3.5 wt.-%, and in particular at least 4.0 wt.-%, relative to the total weight of the one-component adhesive composition.

[0085] Preferably, the total weight content of the phyllosilicate is at most 19 wt.-%, preferably at most 17 wt.-%, more preferably at most 15 wt.-%, still more preferably at most 13 wt.-%, yet more preferably at most 11 wt.-%, even more preferably at most 9.0 wt.-%, most preferably at most 7.0 wt.-%, and in particular at most 5.0 wt.-%, relative to the total weight of the one-component adhesive composition.

[0086] Preferably, the total weight content of the phyllosilicate is within the range of 4.0±3.0 wt.-%, preferably 4.0±1.5 wt.-%, relative to the total weight of the one-component adhesive composition.

[0087] In preferred embodiments, the one-component adhesive composition according to the invention comprises the metal oxide, preferably CaO, and the optional phyllosilicate, preferably organophilic phyllosilicate.

[0088] The one-component adhesive composition according to the invention optionally comprises (f) inosilicate (chain silicate). Silicate minerals are classified into groups according to the structure of their silicate anion: neosilicates (orthosilicates), sorosilicates, cyclosilicates, inosilicates, phyllosilicates, and tectosilicates. Cyclosilicates form rings, inosilicates form single chains or double chains, phyllosilicates form sheets, and tectosilicates form three-dimensional networks. [0089] The inosilicate according to the invention may be selected from single chain inosilicates and double chain inosilicates. Single chain inosilicates are preferred. The single chain inosilicates according to the invention may be selected from the pyroxene group or the pyroxenoid group. Single chain inosilicates from the pyroxenoid group are preferred. Preferably, the inosilicate is selected from wollastonite, rhodonite, or pectolite. Suitable inosilicates such as wollastonite are known to the skilled person and commercially available, e.g. under the tradename Vansil® HR2000.

[0090] Preferably, the inosilicate has the form of particles, flakes, platelets, rods, needles, and/or rectangles; preferably needles.

[0091] In particularly preferred embodiments, the inosilicate comprises or essentially consists of wollastonite; preferably wollastonite needles.

[0092] Preferably, the inosilicate has an aspect ratio of at least 2.0, preferably at least 4.0, more preferably at least 6.0, still more preferably at least 8.0, yet more preferably at least 10, and even more preferably at least 12.

[0093] Preferably, the inosilicate has an aspect ratio of at most 22, preferably at most 20, more preferably at most 18, still more preferably at most 16, yet more preferably at most 14, and even more preferably at most 12.

[0094] Preferably, the inosilicate has an aspect ratio within the range of 12±5.0, preferably 12±2.5.

[0095] Preferably, the inosilicate has a volume median diameter D10 of at least 0.5 pm, preferably at least 1.0 pm, more preferably at least 1.5 pm, still more preferably at least 2.05 pm, yet more preferably at least 2.5 pm, even more preferably at least 3.0 pm, most preferably at least 3.5 pm, and in particular at least 4.0 pm, determined by laser diffraction analysis according to ISO 13320.

[0096] Preferably, the inosilicate has a volume median diameter D10 of at most 12 pm, preferably at most 11 pm, more preferably at most 10 pm, still more preferably at most 9.0 pm, yet more preferably at most 8.0 pm, even more preferably at most 7.0 pm, most preferably at most 6.0 pm, and in particular at most 5.0 pm, determined by laser diffraction analysis according to ISO 13320.

[0097] Preferably, the inosilicate has a volume median diameter D10 within the range of 4.0±2.0 pm, preferably 4.0±1.0 pm, determined by laser diffraction analysis according to ISO 13320.

[0098] Preferably, the inosilicate has a volume median diameter D50 of at least 10 pm, preferably at least 11 pm, more preferably at least 12 pm, still more preferably at least 13 pm, yet more preferably at least 14 pm, even more preferably at least 15 pm, most preferably at least 16 pm, and in particular at least 17 pm, determined by laser diffraction analysis according to ISO 13320.

[0099] Preferably, the inosilicate has a volume median diameter D50 of at most 32 pm, preferably at most 30 pm, more preferably at most 28 pm, still more preferably at most 26 pm, yet more preferably at most 24 gm, even more preferably at most 22 pm, most preferably at most 20 pm, and in particular at most 18 pm, determined by laser diffraction analysis according to ISO 13320.

[0100] Preferably, the inosilicate has a volume median diameter D50 within the range of 17±7.0 pm, preferably 17±3.5 pm, determined by laser diffraction analysis according to ISO 13320.

[0101] Preferably, the inosilicate has a volume median diameter D90 of at least 30 pm, preferably at least 35 pm, more preferably at least 40 pm, still more preferably at least 45 pm, yet more preferably at least 50 pm, even more preferably at least 55 pm, most preferably at least 60 pm, and in particular at least 65 pm, determined by laser diffraction analysis according to ISO 13320.

[0102] Preferably, the inosilicate has a volume median diameter D90 of at most 120 pm, preferably at most 110 pm, more preferably at most 100 pm, still more preferably at most 90 pm, yet more preferably at most 85 pm, even more preferably at most 80 pm, most preferably at most 75 pm, and in particular at most 70 pm, determined by laser diffraction analysis according to ISO 13320.

[0103] Preferably, the inosilicate has a volume median diameter D90 within the range of 65±30 pm, preferably 65±15 pm, determined by laser diffraction analysis according to ISO 13320.

[0104] Preferably, the inosilicate has an average length of at least 30 pm, preferably at least 35 pm, more preferably at least 40 pm, still more preferably at least 45 pm, yet more preferably at least 50 pm, even more preferably at least 55 pm, most preferably at least 60 pm, and in particular at least 65 pm.

[0105] Preferably, the inosilicate has an average length of at most 105 pm, preferably at most 100 pm, more preferably at most 95 pm, still more preferably at most 90 pm, yet more preferably at most 85 pm, even more preferably at most 80 pm, most preferably at most 75 pm, and in particular at most 70 pm.

[0106] Preferably, the inosilicate has an average length within the range 65±30 pm, preferably 65±15 pm.

[0107] Preferably, the inosilicate has an average width of at least 1.0 pm, preferably at least 2.0 pm, more preferably at least 3.0 pm, still more preferably at least 4.0 pm, yet more preferably at least 5.0 pm, even more preferably at least 6.0 pm, and most preferably at least 7.0 pm.

[0108] Preferably, the inosilicate has an average width of at most 20 pm, preferably at most 18 pm, more preferably at most 16 pm, still more preferably at most 14 pm, yet more preferably at most 12 pm, even more preferably at most 10 pm, most preferably at most 9.0 pm, and in particular at most 8.0 pm.

[0109] Preferably, the inosilicate has an average width within the range 7.0±5.0 pm, preferably 7.0±3.5 pm.

[0110] Preferably, the weight content of the inosilicate is at least 3.0 wt.-%, preferably at least 4.0 wt.- %, more preferably at least 5.0 wt.-%, still more preferably at least 6.0 wt.-%, yet more preferably at least 7.0 wt.-%, even more preferably at least 8.0 wt.-%, most preferably at least 9.0 wt .-%, and in particular at least 10 wt.-%, relative to the total weight of the one-component adhesive composition.

[0111] Preferably, the weight content of the inosilicate is at most 30 wt.-%, preferably at most 28 wt.- %, more preferably at most 26 wt.-%, still more preferably at most 24 wt.-%, yet more preferably at most 22 wt.-%, even more preferably at most 20 wt.-%, most preferably at most 18 wt.-%, and in particular at most 16 wt.-%, relative to the total weight of the one-component adhesive composition.

[0112] Preferably, the weight content of the inosilicate is within the range of 15±7.0 wt.-%, preferably 15±3.5 wt.-%, relative to the total weight of the one-component adhesive composition.

[0113] The one-component adhesive composition according to the invention optionally comprises (g) reactive diluent. Preferably, the reactive diluent is an epoxy reactive diluent bearing reactive epoxy functional groups or nucleophilic functional groups that are capable of reacting with epoxy functional groups.

[0114] The reactive diluent may be added to the one-component adhesive composition according to the invention in order to adjust its viscosity. As reactive diluents typically have a comparatively low viscosity, the reactive diluent typically lowers the viscosity of the composition. In this regard, the reactive diluent can lower the viscosity to values that cannot be reached with the liquid epoxy resin alone.

[0115] Preferably, the reactive diluent comprises

- epoxy functional groups;

- hydroxy functional groups;

- aldehyde functional groups;

- oxazolidine functional groups; and/or

- a lactone functional group; preferably epoxy functional groups.

[0116] Preferably, the reactive diluent is a glycidyl ether epoxy resin.

[0117] Preferably, the reactive diluent is selected from phenyl glycidyl ether, alkyl phenol monoglyc- idyl ether, aliphatic monoglycidyl ether, alkylphenol mono glycidyl ether, alkylphenol monoglycidyl ether, 3-glycidoxypropyl trimethoxysilane, 3-glycidoxypropyl trimethoxysilane, 3-glycidoxypropylme- thyldimethox silane, 1 -(3-glycidoxypropyl) 1,1,3,3,3-pentamethyl disiloxane, 1,4-butanediol diglyc- idyl ether, 1,6-hexanediol diglycidyl ether, 1,4-cyclohexanedimethanol, glycidyl ether of soybean oil, glycidyl ether of linseed oil, glycidyl ether of cashew nutshell liquid, diglycidyl ether of resorcinol, diglycidyl ether of cyclohexane dimethanol, diglycidyl ether of neopentyl glycol, diglycidyl ether of cashew nutshell liquid, triglycidyl ether of trimethylolpropane dipentene, trimethylolpropane triglycidyl ether, glycerin triglycidyl ether, pentaerythritol tetraglycidyl ether, and mixtures thereof; preferably glycidyl ether of cashew nutshell liquid, diglycidyl ether of cashew nutshell liquid, and mixtures thereof Suitable reactive diluents are known to the skilled person and are commercially available, e.g. under the tradename Cardura® E10P, Cardolite® NC 514S, Epodil®, and the like.

[0118] Preferably, the reactive diluent has more than one epoxy functional groups; preferably two epoxy functional groups.

[0119] Preferably, the reactive diluent is a diglycidyl ether of cashew nutshell liquid.

[0120] Preferably, the reactive diluent has an epoxy equivalent weight within the range of from 290 to 450 g/eq, preferably from 305 to 435 g/eq, and more preferably from 320 to 420 g/eq, determined according to ASTM DI 652.

[0121] Preferably, the reactive diluent has a viscosity at 25°C within the range of from 0.25 to 12 Pa s, preferably from 0.5 to 6.0 Pa s, more preferably from 1.0 to 3.0 Pa s, determined according to ASTM D2196.

[0122] Preferably, the weight content of the reactive diluent is at least 1.0 wt.-%, preferably at least 2.0 wt.-%, more preferably at least 2.5 wt.-%, still more preferably at least 3.0 wt.-%, yet more preferably at least 3.5 wt.-%, even more preferably at least 4.0 wt.-%, most preferably at least 4.5 wt.-%, and in particular at least 5.0 wt.-%, relative to the total weight of the one-component adhesive composition.

[0123] Preferably, the weight content of the reactive diluent is at most 16 wt.-%, preferably at most 14 wt.-%, more preferably at most 12 wt.-%, still more preferably at most 10 wt.-%, yet more preferably at most 9.0 wt.-%, even more preferably at most 8.0 wt.-%, most preferably at most 7.0 wt.-%, and in particular at most 6.0 wt.-%, relative to the total weight of the one-component adhesive composition.

[0124] Preferably, the weight content of the reactive diluent is within the range of 5.5±3.0 wt.-%, preferably 5.5±1.5 wt.-%, relative to the total weight of the one-component adhesive composition.

[0125] The one-component adhesive composition according to the invention optionally comprises (h) additional curable epoxy resin; preferably semi-solid curable epoxy resin. Viscosities of semi-solid epoxy resins are typically determined at elevated temperature, e.g. 52°C or 55°C.

[0126] Preferably, the additional curable epoxy resin is selected from bisphenol diglycidylether resins, epoxy novolac resins, preferably epoxy phenol novolac resins, and combinations thereof. Preferably, the additional curable epoxy resin is semi-solid.

[0127] Preferably, the additional curable epoxy resin comprises or essentially consists of an epoxy novolac resin, preferably epoxy phenol novolac resin; preferably a semi-solid epoxy novolac resin, preferably epoxy phenol novolac resin.

[0128] Preferably, the additional curable epoxy resin comprises or essentially consists of a bisphenol diglycidylether resin; preferably a dimer acid modified epoxy resin. [0129] Preferably, the additional curable epoxy resin comprises or essentially consists of epoxy novolac resin and bisphenol diglycidylether resin.

[0130] Suitable additional curable epoxy resins such as semi-solid epoxy phenol novolac resins or dimer acid modified epoxy resins are known to the skilled person and commercially available, e.g. under the tradenames Kukdo® YDPN 638, Kukdo® YD172, and the like.

[0131] Dimer acid modified epoxy resins are known to the skilled person and commercially available. Epoxy resins may be classified as six major types, namely (i) bisphenol-A based epoxy resins, (ii) bi- sphenol-F based epoxy resins, (iii) multifunctional epoxies (novolacs), (iv) cycloaliphatic epoxy resins, (v) fire retardant epoxies, and (vi) modified epoxy resins. The latter major type encompasses (a) dimer acid modified epoxy resins besides (b) CTBN modified epoxy resins and (c) silicone modified epoxy resins (see e.g. A.S. Khanna, High-performance organic coatings, Woodhead Publishing, 2008, page 148).

[0132] Preferably, the dimer acid modified epoxy resin according to the invention has the following general formula wherein

R is the moiety of the dimer acid, which may be aliphatic, cycloaliphatic or aromatic, optionally substituted; m is an integer within the range of from 0 to 10; and n is an integer within the range of from 0 to 10.

[0133] Preferably, the additional curable epoxy resin, preferably epoxy novolac resin, more preferably epoxy phenol novolac resin, has an epoxy equivalent weight within the range of from 150 to 210 g/eq, preferably from 160 to 200 g/eq, and more preferably from 170 to 190 g/eq, determined according to ASTM D1652.

[0134] Preferably, the additional curable epoxy resin, preferably the dimer acid modified epoxy resin, has an epoxy equivalent weight within the range of from 400 to 900 g/eq, preferably from 500 to 800 g/eq, and more preferably from 600 to 700 g/eq, determined according to ASTM D1652.

[0135] Preferably, the additional curable epoxy resin, preferably epoxy novolac resin, more preferably epoxy phenol novolac resin, has a solution viscosity of H to K, determined according to Gardner Holdt Method, preferably in butyl carbitol NV 60% solution.

[0136] Preferably, the additional curable epoxy resin has a viscosity at 55°C of at least 100 Pa s, preferably at least 125 Pa s, more preferably at least 150 Pa s, determined according to ASTM D2196.

[0137] Preferably, the additional curable epoxy resin, preferably the dimer acid modified epoxy resin, is semi-solid at 25°C.

[0138] Preferably, the additional curable epoxy resin has an epoxy functionality within the range of from 0.3 to 2.9, preferably from 0.7 to 2.5, more preferably from 1.1 to 2.1.

[0139] Preferably, the weight content of the additional curable epoxy resin is at least 0.5 wt.-%, preferably at least 0.8 wt.-%, more preferably at least 1.1 wt.-%, still more preferably at least 1.4 wt.-%, yet more preferably at least 1.7 wt.-%, even more preferably at least 2.0 wt.-%, most preferably at least 2.3 wt.-%, and in particular at least 2.6 wt.-%, relative to the total weight of the one-component adhesive composition.

[0140] Preferably, the weight content of the additional curable epoxy resin is at most 10 wt.-%, preferably at most 9.0 wt.-%, more preferably at most 8.0 wt.-%, still more preferably at most 7.0 wt.-%, yet more preferably at most 6.0 wt.-%, even more preferably at most 5.0 wt.-%, most preferably at most 4.0 wt.-%, and in particular at most 3.0 wt-%, relative to the total weight of the one-component adhesive composition.

[0141] Preferably, the weight content of the additional curable epoxy resin is within the range of 2.6±2.0 wt.-%, preferably 2.6±1.0 wt.-%, relative to the total weight of the one-component adhesive composition.

[0142] The one-component adhesive composition according to the invention optionally comprises (i) fibers, preferably discontinuous fibers.

[0143] Preferably, the fibers have the form of aggregates, hollow material, chopped material, or mixtures thereof.

[0144] Preferably, the fibers comprise or essentially consist of inorganic fibers, preferably glass (e.g. E-glass or S-glass) fibers or fiberglass; organic fibers, preferably polymer fibers, more preferably selected from polyamide (e g. nylon) fibers, polyester fibers, carbon fibers, aramid fibers, polycarbonate fibers, polyethylene fibers, polypropylene fibers, polybutylene (e g. polybutylene terephthalate) fibers, polystyrene fibers, polyurethane fibers; or mixtures thereof.

[0145] Preferably, the fibers are selected from chopped glass fibers, chopped aramid fibers, aramid pulp and mixtures thereof; preferably chopped glass fibers.

[0146] Suitable fibers such as chopped glass fibers are known to the skilled person and commercially available, e.g. under the trade designation FGCS 3540/3, and the like.

[0147] Preferably, the fibers have an average length of at least 0.5 mm, preferably at least 1.0 mm, more preferably at least 1.5 mm, still more preferably at least 2.0 mm, yet more preferably at least 2.5 mm, even more preferably at least 3.0 mm, most preferably at least 3.5 mm, and in particular at least 4.0 mm.

[0148] Preferably, the fibers have an average length of at most 45 mm, preferably at most 40 mm, more preferably at most 35 mm, still more preferably at most 30 mm, yet more preferably at most 25 mm, even more preferably at most 20 mm, most preferably at most 15 mm, and in particular at most 10 mm.

[0149] Preferably, the fibers have an average length within the range of 7.0±6.0 mm, preferably 7.0±3.0 mm.

[0150] Preferably, the fibers have an average diameter of at least 3.0 pm, preferably at least 4.0 pm, more preferably at least 5.0 pm, still more preferably at least 6.0 pm, yet more preferably at least 7.0 pm, even more preferably at least 8.0 pm, most preferably at least 9.0 pm, and in particular at least 10 pm.

[0151] Preferably, the fibers have an average diameter of at most 45 pm, preferably at most 40 pm, more preferably at most 35 pm, still more preferably at most 30 pm, yet more preferably at most 25 pm, even more preferably at most 20 pm, most preferably at most 15 pm, and in particular at most 12 pm.

[0152] Preferably, the fibers have an average diameter within the range of 10±4.0 mm, preferably 10±2.0 mm.

[0153] Preferably, the weight content of the fibers is at least 1.5 wt.-%, preferably at least 2.0 wt.-%, more preferably at least 2.5 wt.-%, still more preferably at least 3.0 wt.-%, yet more preferably at least 3.5 wt.-%, even more preferably at least 4.0 wt.-%, most preferably at least 4.5 wt-%, and in particular at least 5.0 wt.-%, relative to the total weight of the one-component adhesive composition.

[0154] Preferably, the weight content of the fibers is at most 13 wt.-%, preferably at most 12 wt.-%, more preferably at most 11 wt.-%, still more preferably at most 10 wt.-%, yet more preferably at most 9.0 wt.-%, even more preferably at most 8.0 wt.-%, most preferably at most 7.0 wt.-%, and in particular at most 6.0 wt.-%, relative to the total weight of the one-component adhesive composition. [0155] Preferably, the weight content of the fibers is within the range of 6.0±3.0 wt.-%, preferably 6.0±1.5 wt.-%, relative to the total weight of the one-component adhesive composition.

[0156] The one-component adhesive composition according to the invention optionally comprises (j) polyhydroxy carboxylic acid ester which preferably serves as rheology modifier. Suitable polyhydroxy carboxylic acid esters are known to the skilled person and commercially available, e.g. under the trade- name Rheobyk® R606, and the like.

[0157] Preferably, the total weight content of the polyhydroxy carboxylic acid ester is at least 0.2 wt- %, preferably at least 0.3 wt.-%, more preferably at least 0.4 wt.-%, still more preferably at least 0.5 wt- %, yet more preferably at least 0.6 wt-%, even more preferably at least 0.7 wt-%, most preferably at least 0.8 wt-%, and in particular at least 0.9 wt-%, relative to the total weight of the one-component adhesive composition.

[0158] Preferably, the total weight content of the polyhydroxy carboxylic acid ester is at most 5.0 wt. - %, preferably at most 4.0 wt.-%, more preferably at most 3.0 wt.-%, still more preferably at most 2.0 wt.-%, yet more preferably at most 1.6 wt.-%, even more preferably at most 1.4 wt-%, most preferably at most 1.2 wt-%, and in particular at most 1.0 wt.-%, relative to the total weight of the one-component adhesive composition.

[0159] Preferably, the total weight content of the polyhydroxy carboxylic acid ester is within the range of 1.0±0.9 wt-%, preferably 1.0±0.5 wt.-%, relative to the total weight of the one-component adhesive composition.

[0160] The one-component adhesive composition according to the invention optionally comprises (k) polyamide.

[0161] Preferably, the polyamide is polyamide powder. Suitable polyamide powders are known to the skilled person and commercially available, e.g. under the tradename Crayvallac® (Arkema).

[0162] Preferably, the polyamide has the form of particles, flakes, platelets, rods, needles, and/or rectangles.

[0163] Preferably, the total weight content ofthe polyamide is at least 1.0 wt-%, preferably at least 1.5 wt-%, more preferably at least 2.0 wt-%, still more preferably at least 2.5 wt-%, yet more preferably at least 3.0 wt-%, even more preferably at least 3.5 wt-%, most preferably at least 4.0 wt-%, and in particular at least 4.5 wt-%, and in particular at least 5.0 wt-%, relative to the total weight of the one- component adhesive composition.

[0164] Preferably, the total weight content of the polyamide is at most 15 wt-%, preferably at most 12 wt-%, more preferably at most 11 wt-%, still more preferably at most 10 wt-%, yet more preferably at most 9.0 wt-%, even more preferably at most 8.0 wt-%, most preferably at most 7.0 wt-%, and in particular at most 6.0 wt-%, relative to the total weight of the one-component adhesive composition. [0165] Preferably, the total weight content of the polyamide is within the range of 5.0±3.0 wt.-%, preferably 5.0±1.5 wt.-%, relative to the total weight of the one-component adhesive composition.

[0166] The one-component adhesive composition according to the invention optionally comprises (1) blowing agent. The blowing agent may be selected from chemical blowing agent, physical blowing agents, preferably expandable thermoplastic microspheres, and mixtures thereof.

[0167] Preferably, the one-component adhesive composition is capable of foaming upon activation by heat or any other suitable stimulus. Thus, the material exists in two states, foamable and foamed. Typically, the foamable thermoplastic material becomes a thermoset material after foaming. In the initial foamable state, the material is typically stable at room temperature. Upon heating to its activation temperature, the material undergoes volume expansion due to the activated foaming process thereby yielding the final foamed state of the material. Preferably, the blowing agent (foaming agent) enables the foaming process. At elevated temperature or other activation conditions, the blowing agent decomposes and releases gases. This typically goes along with curing of the composition which is designed to undergo curing at such elevated temperature.

[0168] Preferably, the blowing agent is a chemical blowing agent, preferably selected from the group consisting of azodicarbonamide, dinitrosopentamethylenetetramme, hydrazides such as 4,4-oxy-bis- (benzene-sulphonylhydrazide), trihydrazinotriazine, N,N'-dimethyl-N,N'-dinitrosoterephthalamide, toluenesulfonyl hydrazide (TSH), p-toluenesulfonyl semicarbazide (TSSC), 5-phenyl tetrazole (5-PT), or N-N'-dinitrosopentamethylene tetramine (DNPT); preferably azodicarbonamide. Suitable chemical blowing agents such as azodicarbonamide are known to the skilled person and commercially available, e g. under the tradename Cellcom® AC7000DB, and the like.

[0169] In other preferred embodiments, the blowing agent is physical blowing agents, preferably expandable thermoplastic microspheres. Suitable physical blowing agents such as expandable thermoplastic microspheres are known to the skilled person and commercially available, e g. under the trade- name Expancel®, Advance!!®, and the like.

[0170] Preferably, the weight content of the blowing agent is at least 0.2 wt.-%, preferably at least 0.3 wt.-%, more preferably at least 0.4 wt.-%, still more preferably at least 0.5 wt.-%, yet more preferably at least 0.6 wt.-%, even more preferably at least 0.7 wt.-%, most preferably at least 0.8 wt.-%, and in particular at least 0.9 wt.-%, relative to the total weight of the one-component adhesive composition.

[0171] Preferably, the weight content of the blowing agent is at most 5.0 wt.-%, preferably at most 4.0 wt.-%, more preferably at most 3.0 wt.-%, still more preferably at most 2.0 wt .-%, yet more preferably at most 1.6 wt.-%, even more preferably at most 1.4 wt.-%, most preferably at most 1.2 wt.-%, and in particular at most 1.0 wt.-%, relative to the total weight of the one-component adhesive composition.

[0172] Preferably, the weight content of the blowing agent is within the range of 1.0±0.9 wt.-%, preferably 1.0±0.5 wt.-%, relative to the total weight of the one-component adhesive composition. [0173] The one-component adhesive composition according to the invention optionally comprises (m) impact modifier. For the purpose of the specification, an impact modifier increases the durability. Impact modifiers are known to the skilled person (see e.g. Berzins A.P. Impact Modifiers, Chapter 8 in Lutz J.T., Grossmann R.F. Polymer Modifiers and Adhesives (2001), Marcel Dekker).

[0174] Functionalized elastomer adduct impact modifiers according to the invention are preferably epoxy functionalized or carboxyl functionalized. The elastomer portion may be based on e.g. acryloni- trile/butadiene copolymer. Functionalized acrylomtrile/butadiene copolymers of this type are commercially available, e.g. under the tradenames Hypro™ (Hycar®) CTBN, CTBNX and ETBN.

[0175] Preferably, the impact modifier is selected from functionalized elastomer adducts, preferably elastomer/epoxy adducts, core shell impact modifiers, and combinations thereof. Suitable impact modifier are known to the skilled person and commercially available, e.g. under the tradenames Clearstrength® E950, Kane Ace® MX257 (37/63 CRS/EPX), Struktol Polydis® 3695, Albipox® 8001, and the like. Particularly suitable modified acrylonitrile/butadiene copolymers are those liquid rubbers marketed within the Polydis® product range by Struktol® (Schill-Seilacher), or Albipox® (Nanoresins).

[0176] Core-shell impact modifiers according to the invention generally include graft copolymers that may be characterized as core-shell copolymers having a rubbery "core," a hard "shell," and that swell in the methacrylate and/or acrylate monomer compositions but do not dissolve therein. Examples of coreshell copolymers are those where the hard "shell" monomers, such as styrene, acrylonitrile, or methyl methacrylate, are grafted onto a rubbery "core" made from polymers of butadiene, butyl acrylate, ethyl acrylate, isoprene and the like. One type of core-shell polymers is methacrylate butadiene styrene (MBS) copolymer made by polymerizing methyl methacrylate in the presence of polybutadiene or a polybutadiene copolymer rubber. Commercial examples of core shell impact modifiers are ParaloidTM BTA- 753, Paraloid 2650A, Paraloid 2691A, Clearstrength® E920, Clearstrength XT 100, and Kane AceTM B-564 or Kane AceTM M521.

[0177] In preferred embodiments, the impact modifier is a core shell impact modifier selected from impact modifiers based on butadiene, isoprene, ethylene-propylene and ethylene-butylene in combination with styrene, acrylonitrile and acrylic monomers; acrylonitrile butadiene styrene (ABS) impact modifiers; methacrylate butadiene styrene (MBS) impact modifiers; and MABS impact modifiers.

[0178] In a preferred embodiment, the impact modifier is a (methyl)methacrylate butadiene styrene (MBS) core shell impact modifier. Thus, the impact modifier preferably is a core-shell copolymer where hard "shell" acrylate monomers (preferably (methyl)methacrylates) are grafted onto a rubbery "core" made from butadiene styrene rubber. Impact modifiers of this type are commercially available (e.g. Kane AceTM B564, Kane AceTM M521, ClearstrengthTM XT 100, Paraloid 2650A, Paraloid 2691A, Clearstrength® E920, Clearstrength XT 100). [0179] In another preferred embodiment, the impact modifier is a core shell polybutadiene rubber, which may be dispersed in liquid bisphenol A epoxy resin (e.g. Kane AceTM MX257).

[0180] In still another preferred embodiment, the impact modifier is a a core shell impact modifier having an all-acrylic core shell based on butyl-acrylate rubber. Thus, the impact modifier preferably is a core-shell copolymer where hard "shell" acrylate monomers (preferably (methyl)methacrylates) are grafted onto a rubbery "core" made from butyl acrylate rubber. First impact modifiers of this type are commercially available (e.g. ParaloidTM EXL-2300G, Paraloid EXL-2314, Paraloid EXL 3361).

[0181] Preferably, the one-component adhesive composition according to the invention comprises a first impact modifier and optionally a second impact modifier.

[0182] Preferably, the first impact modifier comprises a methylmethacrylate-butadiene-styrene (MBS) core shell polymer.

[0183] In preferred embodiments, the first impact modifier is a solid impact modifier; preferably a solid methylmethacrylate-butadiene-styrene (MBS) core shell impact modifier.

[0184] Preferably, the weight content of the first impact modifier, preferably the solid first impact modifier, is at least 1.0 wt.-%, preferably at least 2.0 wt.-%, more preferably at least 3.0 wt.-%, still more preferably at least 4.0 wt.-%, yet more preferably at least 5.0 wt.-%, even more preferably at least 6.0 wt.-%, most preferably at least 7.0 wt.-%, and in particular at least 8.0 wt.-%, relative to the total weight of the one-component adhesive composition.

[0185] Preferably, the weight content of the first impact modifier, preferably the solid first impact modifier, is at most 22 wt.-%, preferably at most 20 wt.-%, more preferably at most 18 wt.-%, still more preferably at most 16 wt.-%, yet more preferably at most 14 wt.-%, even more preferably at most 12 wt.-%, most preferably at most 10 wt.-%, and in particular at most 9.0 wt.-%, relative to the total weight of the one-component adhesive composition.

[0186] Preferably, the weight content of the first impact modifier, preferably the solid first impact modifier, is within the range of 8.0±5.0 wt.-%, preferably 8.0±3.0 wt.-%, relative to the total weight of the one-component adhesive composition.

[0187] In further preferred embodiments, the first impact modifier is a liquid impact modifier; preferably a methylmethacrylate-butadiene-styrene (MBS) core shell polymer dispersed in bisphenol A epoxy resin.

[0188] Preferably, the weight content of the first impact modifier, preferably the liquid first impact modifier, is at least 6.0 wt.-%, preferably at least 8.0 wt.-%, more preferably at least 10 wt.-%, still more preferably at least 12 wt-%, yet more preferably at least 14 wt.-%, even more preferably at least 16 wt- %, most preferably at least 18 wt.-%, and in particular at least 20 wt.-%, relative to the total weight of the one-component adhesive composition. [0189] Preferably, the weight content of the first impact modifier, preferably the liquid first impact modifier, is at most 36 wt.-%, preferably at most 34 wt.-%, more preferably at most 32 wt.-%, still more preferably at most 30 wt.-%, yet more preferably at most 28 wt.-%, even more preferably at most 26 wt.-%, most preferably at most 24 wt.-%, and in particular at most 22 wt.-%, relative to the total weight of the one-component adhesive composition.

[0190] Preferably, the weight content of the first impact modifier, preferably the liquid first impact modifier, is within the range of 20±10 wt.-%, preferably 20±5.0 wt.-%, relative to the total weight of the one-component adhesive composition.

[0191] Preferably, the second impact modifier is an elastomer/epoxy adduct; preferably a nitrile rubber modified epoxy resin; still more preferably a nitrile rubber modified epoxy resin based on bisphenol-A- diglycidylether.

[0192] Preferably, the weight content of the second impact modifier is at least 1.0 wt.-%, preferably at least 2.0 wt.-%, more preferably at least 3.0 wt.-%, still more preferably at least 4.0 wt.-%, yet more preferably at least 5.0 wt.-%, even more preferably at least 6.0 wt.-%, most preferably at least 7.0 wt.- %, and in particular at least 8.0 wt.-%, relative to the total weight of the one-component adhesive composition.

[0193] Preferably, the weight content of the second impact modifier is at most 22 wt.-%, preferably at most 20 wt.-%, more preferably at most 18 wt.-%, still more preferably at most 16 wt.-%, yet more preferably at most 14 wt-%, even more preferably at most 12 wt.-%, most preferably at most 10 wt.-%, and in particular at most 9.0 wt.-%, relative to the total weight of the one-component adhesive composition.

[0194] Preferably, the weight content of the second impact modifier is within the range of 8.0±5.0 wt. - %, preferably 8.0±3.0 wt.-%, relative to the total weight of the one-component adhesive composition.

[0195] The one-component adhesive composition according to the invention optionally comprises (n) toughening agent and/or flexibilizer. For the purpose of the specification, a toughening agent increases the ability of the material to absorb energy and plastically deform without fracture. Typical toughening agents are rubbers (elastomers) that can be interspersed as nanoparticles within a polymer matrix to increase the mechanical robustness, or toughness, of the material. Toughening agents are known to the skilled person (see e.g. Bucknail C.B. (1977) Toughened Plastics, Springer; Keskkula H., Paul D R (1994) Toughening agents for engineering polymers. In: Collyer A.A. (eds) Rubber Toughened Engineering Plastics. Springer; Arends Ch. (1996) Polymer Toughening, Marcel Dekker). Suitable toughening agents / flexibilizers are known to the skilled person and commercially available, e.g. under the tradename Butvar® B90 (Eastman), DY 965 CH (Huntsman), and the like.

[0196] Preferably, the toughening agent and/or flexibilizer is selected from the group consisting of polyolefins, polyurethanes, polyvinyl acetals, polyvinyl acetate, polyvinyl alcohols, polytetrafluoro- ethylene, acrylic resins, polyvinyl chloride, polyvinylidene chloride, polystyrene, and combinations thereof; preferably polyurethanes, polyvinyl acetals, and combinations thereof.

[0197] Preferably, the toughening agent and/or flexibilizer comprises or essentially consists of a capped polyurethane adduct and/or a polyvinyl acetal resin; preferably a phenol terminated polyurethane adduct and/or a polyvinyl butyral resin.

[0198] Polyvinyl esters in particular polyvinyl butyral resins such as the Butvar® resins, particularly Butvar® 90 and the Mowital® resins are preferred.

[0199] Preferably, the total weight content of the toughening agent and/or flexibilizer is at least 1.0 wt.- %, preferably at least 1.5 wt.-%, more preferably at least 2.0 wt.-%, still more preferably at least 2.5 wt.- %, yet more preferably at least 3.0 wt.-%, even more preferably at least 3.5 wt.-%, most preferably at least 4.0 wt.-%, and in particular at least 4.5 wt.-%, relative to the total weight of the one-component adhesive composition.

[0200] Preferably, the total weight content of the toughening agent and/or flexibilizer is at most 18 wt.- %, preferably at most 16 wt.-%, more preferably at most 14 wt.-%, still more preferably at most 12 wt.- %, yet more preferably at most 10 wt.-%, even more preferably at most 9.0 wt.-%, most preferably at most 8.0 wt.-%, and in particular at most 7.0 wt.-%, relative to the total weight of the one-component adhesive composition.

[0201] Preferably, the total weight content of the toughening agent and/or flexibilizer is within the range of 6.0±4.0 wt.-%, preferably 6.0±2.0 wt.-%, relative to the total weight of the one-component adhesive composition.

[0202] The one-component adhesive composition according to the invention optionally comprises (o) phenoxy resin; preferably solid phenoxy resin; more preferably solid phenoxy resin which is a copolymer of bisphenol A and epichlorohydrin.

[0203] Suitable phenoxy resins are known to the skilled person and commercially available, e.g. under the trade designations PKHA, PKHB, PKHC, PKHH, PKHJ, PKFE, PKHP, PKHS (InChemRez) or Epokukdo® YP-50.

[0204] The phenoxy resin may be added to the one-component adhesive composition according to the invention in order to adjust its viscosity.

[0205] Preferably, the weight content of the phenoxy resin is at least 3.0 wt-%, preferably at least 4.0 wt.-%, more preferably at least 5.0 wt.-%, still more preferably at least 6.0 wt.-%, yet more preferably at least 7.0 wt.-%, even more preferably at least 8.0 wt.-%, most preferably at least 9.0 wt.-%, and in particular at least 10 wt.-%, relative to the total weight of the one-component adhesive composition. [0206] Preferably, the weight content of the phenoxy resin is at most 26 wt.-%, preferably at most 24 wt.-%, more preferably at most 22 wt-%, still more preferably at most 20 wt.-%, yet more preferably at most 18 wt.-%, even more preferably at most 16 wt.-%, most preferably at most 14 wt.-%, and in particular at most 12 wt.-%, relative to the total weight of the one-component adhesive composition.

[0207] Preferably, the weight content of the phenoxy resin is within the range of 10±6.0 wt.-%, preferably 10±3.0 wt.-%, relative to the total weight of the one-component adhesive composition.

[0208] The one-component adhesive composition according to the invention optionally comprises (p) curing accelerator.

[0209] Preferably, the curing accelerator is selected from the group consisting of modified or unmodified urea, imidazoles, secondary amines, tertiary amines, quaternary ammonium salts, and pyridines; preferably modified urea. Suitable curing accelerators are known to the skilled person and commercially available, e.g. under the tradename Dyhard® UR 400.

[0210] Preferably, the weight content of the curing accelerator is at least 0.1 wt.-%, preferably at least 0.2 wt.-%, more preferably at least 0.25 wt.-%, still more preferably at least 0.3 wt.-%, yet more preferably at least 0.35 wt.-%, even more preferably at least 0.4 wt.-%, most preferably at least 0.45 wt.-%, and in particular at least 0.5 wt.-%, relative to the total weight of the one-component adhesive composition.

[0211] Preferably, the weight content of the curing accelerator is at most 2.5 wt.-%, preferably at most 2.0 wt.-%, more preferably at most 1.75 wt.-%, still more preferably at most 1.5 wt.-%, yet more preferably at most 1.25 wt.-%, even more preferably at most 1.0 wt.-%, most preferably at most 0.75 wt.- %, and in particular at most 0.5 wt.-%, relative to the total weight of the one-component adhesive composition.

[0212] Preferably, the weight content of the curing accelerator is within the range of 0.5±0.4 wt.-%, preferably 0.5±0.2 wt.-%, relative to the total weight of the one-component adhesive composition.

[0213] Preferably, the one-component adhesive composition according to the invention additionally comprises a fdler selected from the group consisting of carbonates, borates, oxides, hydroxides, sulfates, titanates, zirconates, and mixtures thereof.

[0214] Preferably, the weight content of the additional fdler is within the range of 5.0±4.5 wt, relative to the total weight of the one-component adhesive composition.

[0215] Preferably, the additional fdler has the form of particles, flakes, platelets, rods, needles, and/or rectangles.

[0216] The one-component adhesive composition according to the invention may include one or more additives (e.g., functional additives) for improving one or more various properties of the composition. As examples, additives may include antioxidants, antiozonants, ultraviolet absorbers, ultraviolet resistant agents, lubricants, antistatic agents, colorants, flame retardants, heat stabilizers, plasticizers, preservatives, processing aids, stabilizers, or combinations thereof, or the like.

[0217] In preferred embodiments, the curable one-component adhesive composition according to the invention comprises inosilicate, preferably wollastonite, as well as metal oxide, preferably calcium carbonate, wherein the weight content of inosilicate is greater than the weight content of metal oxide, preferably within the range or from 5 : 1 to 1.5: 1.

[0218] In preferred embodiments, the curable one-component adhesive composition according to the invention comprises inosilicate, preferably wollastonite, as well as phyllosilicate, preferably strontium zinc phosphosilicate, wherein the weight content of inosilicate is greater than the weight content of phyllosilicate, preferably within the range or from 15: 1 to 2: 1.

[0219] In preferred embodiments, the curable one-component adhesive composition according to the invention comprises inosilicate, preferably wollastonite, as well as silica, preferably fumed silica, more preferably polydimethylsiloxane treated fumed silica, wherein the weight content of inosilicate is greater than the weight content of silica, preferably within the range or from 10: 1 to 2: 1.

[0220] Preferably, the total content of (a) liquid epoxy resin, (b) latent curing agent, (c) silica, and (d) metal oxide is at least 40 wt-%, preferably at least 42.5 wt.-%, more preferably at least 45 wt.-%, still more preferably at least 47.5 wt.-%, yet more preferably at least 50 wt.-%, even more preferably at least 52.5 wt.-%, most preferably at least 55 wt.-%, and in particular at least 57.5 wt.-%, relative to the total weight of the composition.

[0221] Preferably, the total content of (a) liquid epoxy resin, (b) latent curing agent, (c) silica, (d) metal oxide, (e) optional phyllosilicate if present, and (f) optional inosilicate if present is at least 50 wt.-%, preferably at least 52.5 wt.-%, more preferably at least 55 wt.-%, still more preferably at least 57.5 wt.- %, yet more preferably at least 60 wt.-%, even more preferably at least 62.5 wt.-%, most preferably at least 65 wt.-%, and in particular at least 67.5 wt.-%, relative to the total weight of the composition.

[0222] In preferred embodiments, the curable one-component adhesive composition according to the invention comprises at least 20 wt.-%, preferably 20 to 60 wt.-% liquid epoxy resin, preferably comprising or essentially consisting of liquid epoxy novolac resin, more preferably liquid epoxy phenol novolac resin; and at least 10 wt.-%, preferably 10 to 25 wt.-% inosilicate, preferably wollastonite; relative to the total weight of the composition.

[0223] In preferred embodiments, the curable one-component adhesive composition according to the invention comprises at least 20 wt.-%, preferably 20 to 60 wt.-% liquid epoxy resin, preferably comprising or essentially consisting of liquid epoxy novolac resin, more preferably liquid epoxy phenol novolac resin; at least 10 wt.-%, preferably 10 to 25 wt.-% inosilicate, preferably wollastonite; and at least 3.0 wt.-%, preferably 3.0 to 7.0 wt.-% metal oxide, preferably calcium oxide; relative to the total weight of the composition.

[0224] In preferred embodiments, the curable one-component adhesive composition according to the invention comprises at least 20 wt.-%, preferably 20 to 60 wt.-% liquid epoxy resin, preferably comprising or essentially consisting of liquid epoxy novolac resin, more preferably liquid epoxy phenol novolac resin; at least 10 wt.-%, preferably 10 to 25 wt.-% inosilicate, preferably wollastonite; at least 3.0 wt.-%, preferably 3.0 to 7.0 wt.-% metal oxide, preferably calcium oxide; and at least 3.0 wt.-%, preferably 3.0 to 7.0 wt.-% silica, preferably fumed silica, more preferably polydimethylsiloxane treated fumed silica; relative to the total weight of the composition.

[0225] In preferred embodiments, the curable one-component adhesive composition according to the invention comprises at least 20 wt-%, preferably 20 to 60 wt.-% liquid epoxy resin, preferably comprising or essentially consisting of liquid epoxy novolac resin, more preferably liquid epoxy phenol novolac resin; at least 10 wt.-%, preferably 10 to 25 wt.-% inosilicate, preferably wollastonite; at least 3.0 wt.-%, preferably 3.0 to 7.0 wt.-% metal oxide, preferably calcium oxide; and at least 0.5 wt.-%, preferably 0.5 to 5.0 wt.-% phyllosilicate, preferably strontium zinc phosphosilicate; relative to the total weight of the composition.

[0226] In preferred embodiments, the curable one-component adhesive composition according to the invention comprises at least 20 wt.-%, preferably 20 to 60 wt.-% liquid epoxy resin, preferably comprising or essentially consisting of liquid epoxy novolac resin, more preferably liquid epoxy phenol novolac resin; at least 10 wt.-%, preferably 10 to 25 wt.-% inosilicate, preferably wollastonite; at least 3.0 wt.-%, preferably 3.0 to 7.0 wt.-% metal oxide, preferably calcium oxide; 3.0 to 7.0 wt.-% silica, preferably fumed silica, more preferably polydimethylsiloxane treated fumed silica; and at least 0.5 wt.- %, preferably 0.5 to 5.0 wt.-% phyllosilicate, preferably strontium zinc phosphosilicate; relative to the total weight of the composition.

[0227] In preferred embodiments, the curable one-component adhesive composition according to the invention comprises or essentially consists of

- (a) liquid epoxy resin and optionally (g) reactive diluent, wherein the total weight content of the liquid epoxy resin and the reactive diluent is at least 40 wt.-%, preferably at least 42.5 wt.-%, more preferably at least 45 wt.-%, still more preferably at least 47.5 wt.-%, yet more preferably at least 50 wt.-%, even more preferably at least 52.5 wt.-%, most preferably at least 55 wt.-%, and in particular at least 57.5 wt.-%, relative to the total weight of the one-component adhesive composition;

- (b) latent epoxy curing agent;

- (c) silica;

- (d) metal oxide; - (e) phyllosilicate and/or (f) inosilicate, wherein the total weight content of the phyllosilicate and/or inosilicate is at least 2.5 wt-%, preferably at least 5 wt.-%, more preferably at least 7.5 wt.-%, still more preferably at least 10 wt.-%, yet more preferably at least 12.5 wt.-%, even more preferably at least 15 wt.-%, most preferably at least 17.5 wt.-%, and in particular at least 20 wt.-%, relative to the total weight of the one-component adhesive composition; and

- (m) impact modifier and/or (n) toughening agent and/or flexibilizer, wherein the total weight content of impact modifier and/or toughening agent and/or flexibilizer is at least 2.5 wt.-%, preferably at least 5 wt.-%, more preferably at least 7.5 wt.-%, still more preferably at least 10 wt.-%, yet more preferably at least 12.5 wt.-%, even more preferably at least 15 wt.-%, most preferably at least 17.5 wt.-%, and in particular at least 20 wt.-%, relative to the total weight of the one-component adhesive composition.

[0228] In preferred embodiments, the curable one-component adhesive composition according to the invention comprises or essentially consists of

- (a) liquid epoxy resin and optionally (g) reactive diluent, wherein the total weight content of the liquid epoxy resin and the reactive diluent is at least 40 wt.-%, preferably at least 42.5 wt.-%, more preferably at least 45 wt.-%, still more preferably at least 47.5 wt.-%, yet more preferably at least 50 wt.-%, even more preferably at least 52.5 wt.-%, most preferably at least 55 wt.-%, and in particular at least 57.5 wt.-%, relative to the total weight of the one-component adhesive composition;

- (b) latent epoxy curing agent;

- (c) silica;

- (d) metal oxide;

- (e) phyllosilicate and/or (f) inosilicate, wherein the total weight content of the phyllosilicate and/or inosilicate is at least 2.5 wt-%, preferably at least 5 wt.-%, more preferably at least 7.5 wt-%, still more preferably at least 10 wt-%, yet more preferably at least 12.5 wt-%, even more preferably at least 15 wt-%, most preferably at least 17.5 wt-%, and in particular at least 20 wt-%, relative to the total weight of the one-component adhesive composition; and

- (1) blowing agent;

- (m) impact modifier and/or (n) toughening agent and/or flexibilizer, wherein the total weight content of impact modifier and/or toughening agent and/or flexibilizer is at least 2.5 wt-%, preferably at least 5 wt.-%, more preferably at least 7.5 wt-%, still more preferably at least 10 wt-%, yet more preferably at least 12.5 wt -%, even more preferably at least 15 wt -%, most preferably at least 17.5 wt-%, and in particular at least 20 wt-%, relative to the total weight of the one-component adhesive composition. [0229] Preferably, the one-component adhesive composition according to the invention is thermally curable.

[0230] Preferably, the one-component adhesive composition according to the invention is pumpable; preferably with conventional equipment.

[0231] Preferably, the composition is pumpable at a temperature of at least 20°C, preferably at least 25°C, more preferably at least 30°C, still more preferably at least 35°C, yet more preferably at least 40°C, even more preferably at least 45°C, most preferably at least 50°C, and in particular at least 55°C.

[0232] Preferably, the composition is pumpable at a temperature of at most 105 °C, preferably at most 100°C, more preferably at most 95°C, still more preferably at most 90°C, yet more preferably at most 85°C, even more preferably at most 80°C, most preferably at most 75°C, and in particular at most 70°C.

[0233] Preferably, the composition is pumpable at a temperature within the range of 42±36°C, preferably 42±18°C.

[0234] Preferably, the one-component adhesive composition according to the invention has a viscosity at 25°C of at least 2.0 Pa s, preferably at least 4.0 Pa s, more preferably at least 6.0 Pa s, still more preferably at least 8.0 Pa s, yet more preferably at least 10 Pa s, even more preferably at least 12 Pa s, most preferably at least 14 Pa s, and in particular at least 16 Pa s, determined according to ASTM D1084-16.

[0235] Preferably, the composition has a viscosity at 25°C of at most 1000 Pa s, preferably at most 800 Pa s, more preferably at most 600 Pa s, still more preferably at most 500 Pa s, yet more preferably at most 400 Pa s, even more preferably at most 300 Pa s, most preferably at most 200 Pa s, and in particular at most 150 Pa s, determined according to ASTM D1084-16.

[0236] Preferably, the composition has a viscosity at 25°C of at most 120 Pa s, preferably at most 110 Pa s, more preferably at most 100 Pa s, still more preferably at most 90 Pa s, yet more preferably at most 80 Pa s, even more preferably at most 70 Pa s, most preferably at most 60 Pa s, and in particular at most 50 Pa s, determined according to ASTM D1084-16.

[0237] Preferably, the composition has a viscosity at 25°C within the range of 100±50 Pa s, or 150±100 Pa s, or 150±50 Pa s, or 200±150 Pa s, or 200±100 Pa s, or 200±50 Pa s, or 250±200 Pa s, or 250±150 Pa s, or 250±100 Pa s, or 250±50 Pa s, or 300±250 Pa s, or 300±200 Pa s, or 300±150 Pa s, or 300±100

Pa s, or 300±50 Pa s, or350±300 Pa s, or 350±250 Pa s, or 350±200 Pa s, or 350±150 Pa s, or 350±100

Pa s, or 350±50 Pa s, or400±350 Pa s, or 400±300 Pa s, or 400±250 Pa s, or 400±200 Pa s, or 400±150

Pa s, or 400±100 Pa s, or 400±50 Pa s, or 450±400 Pa s, or 450±350 Pa s, or 450±300 Pa s, or 450±250

Pa s, or 450±200 Pa s, or 450±150 Pa s, or 450±100 Pa s, or 450±50 Pa s, or 500±450 Pa s, or 500±400 Pa s, or 500±350 Pa s, or 500±300 Pa s, or 500±250 Pa s, or 500±200 Pa s, or 500±150 Pa s, or 500±100 Pa s, or 500±50 Pa s, or 550±50 Pa s, or 550±450 Pa s, or 550±400 Pa s, or 550±350 Pa s, or 550±300 Pa-s, or 550±250 Pa-s, or 550±200 Pa-s, or 550±150 Pa-s, or 550±100 Pa s, or 550±50 Pa-s, or 600±550 Pa s, or 600±500 Pa s, or 600±450 Pa s, or 600±400 Pa s, or 600±350 Pa s, or 600±300 Pa s, or 600±250 Pa s, or 600±200 Pa s, or 600±150 Pa s, or 600±100 Pa s, or 600±50 Pa s, or 650±600 Pa s, or 650±550 Pa s, or 650±500 Pa s, or 650±450 Pa s, or 650±400 Pa s, or 650±350 Pa s, or 650±300 Pa s, or 650±250 Pa s, or 650±200 Pa s, or 650±150 Pa s, or 650±100 Pa s, or 650±50 Pa s, or 700±650 Pa s, or 700±600 Pa s, or 700±550 Pa s, or 700±500 Pa s, or 700±450 Pa s, or 700±400 Pa s, or 700±350 Pa s, or 700±300 Pa s, or 700±250 Pa s, or 700±200 Pa s, or 700±150 Pa s, or 700±100 Pa s, or 700±50 Pa s, determined according to ASTM D1084-16.

[0238] Preferably, the composition has a viscosity at 25°C within the range of 10±5.0 Pa s, or 15±10 Pa s, or 15±5.0 Pa s, or 20±15 Pa s, or 20±10 Pa s, or 20±5.0 Pa s, or 25±20 Pa s, or 25±15 Pa s, or 25±10 Pa s, or 25±5.0 Pa s, or 30±25 Pa s, or 30±20 Pa s, or 30±15 Pa s, or 30±10 Pa s, or 30±5.0 Pa s, or 35±30 Pa s, or 35±25 Pa s, or 35±20 Pa s, or 35±15 Pa s, or 35±10 Pa s, or 35±5.0 Pa s, or 40±35 Pa s, or 40±30 Pa s, or 40±25 Pa s, or 40±20 Pa s, or 40±15 Pa s, or 40±10 Pa s, or 40±5.0 Pa s, or 45±40 Pa s, or 45±35 Pa s, or 45±30 Pa s, or 45±25 Pa s, or 45±20 Pa s, or 45±15 Pa s, or 45±10 Pa s, or 45±5.0 Pa s, or 50±45 Pa s, or 50±40 Pa s, or 50±35 Pa s, or 50±30 Pa s, or 50±25 Pa s, or 50±20 Pa s, or 50±15 Pa s, or 50±10 Pa s, or 50±5.0 Pa s, or 55±50 Pa s, or 55±45 Pa s, or 55±40 Pa s, or 55±35 Pa s, or 55±30 Pa s, or 55±25 Pa s, or 55±20 Pa s, or 55±15 Pa s, or 55±10 Pa s, or 55±5.0 Pa s, or 60±55 Pa s, or 60±50 Pa s, or 60±45 Pa s, or 60±40 Pa s, or 60±35 Pa s, or 60±30 Pa s, or 60±25 Pa s, or 60±20 Pa s, or 60±15 Pa s, or 60±10 Pa s, or 60±5.0 Pa s, or 65±60 Pa s, or 65±55 Pa s, or 65±50 Pa s, or 65±45 Pa s, or 65±40 Pa s, or 65±35 Pa s, or 65±30 Pa s, or 65±25 Pa s, or 65±20 Pa s, or 65±15 Pa s, or 65±10 Pa s, or 65±5.0 Pa s, or 70±65 Pa s, or 70±60 Pa s, or 70±55 Pa s, or 70±50 Pa-s, or 70±45 Pa s, or 70±40 Pa-s, or 70±35 Pa s, or 70±30 Pa-s, or 70±25 Pa-s, or 70±20 Pa-s, or 70±15 Pa s, or 70±10 Pa s, or 70±5.0 Pa s, determined according to ASTM DI 084- 16.

[0239] Preferably, the one-component adhesive composition according to the invention is wash-out resistant; preferably in accordance with BMW standard AA-0044 from January 2018. Preferably, the wash-out resistance test involves the following steps:

(a) a bead of the adhesive composition is applied to a hot dip galvanized steel panel (DX54D+Z100, 200 x 40 mm) with an oil layer (PL3802-39S, 1.5 g/m ² = 0.12 g), wherein the steel panel is used as base panel without top panel;

(b) without precuring, the thus prepared sample is placed in an immersion jig and dropped unimpeded from a height of 20 cm into a tank filled with pure water at room temperature;

(c) the sample is mounted to a stirrer in a second tank filled with pure water preheated to 60°C;

(d) the sample is stirred for 3 minutes at a velocity of 140 rpm ( 1.47 m/s);

(e) the sample is removed and visually inspected, wherein the adhesive composition passes the washout resistance test when no significant changes to the adhesive composition are detected. [0240] Preferably, the composition is resistant to aging; preferably under humid conditions; more preferably in accordance with PSA D47 1165, preferably PSA D47 1165 (H7).

[0241] Preferably, the one-component adhesive composition according to the invention is thermally expandable.

[0242] Preferably, the composition exhibits a volume expansion at 190°C of at least 10 vol.-%, preferably at least 50 vol.-%, more preferably at least 100 vol.-%, still more preferably at least 150 vol.-%, relative to the volume of the composition prior to expansion.

[0243] Preferably, the composition exhibits a volume expansion at 190°C of at most 450 vol.-%, preferably at most 400 vol.-%, more preferably at most 350 vol.-%, still more preferably at most 300 vol.- %, relative to the volume of the composition prior to expansion.

[0244] Preferably, the composition exhibits a volume expansion at 190°C within the range of 250±100 vol.-%, preferably 250±50 vol.-%, relative to the volume of the composition prior to expansion.

[0245] Another aspect of the invention relates to a method for preparing a reinforced structural member, the method comprising the steps of

(a) applying a composition according to the invention as described above onto a surface of the structural element;

(b) allowing the applied composition to cure thereby obtaining the reinforced structural member comprising the composition in a cured state.

[0246] Preferably, step (a) of the method according to the invention involves extrusion.

[0247] Preferably, step (a) of the method according to the invention is performed by means of a robot.

[0248] Another aspect of the invention relates to a reinforced structural member comprising a structural element and a composition according to the invention as described above in a cured state.

[0249] Preferably, the reinforced structural member is a structural panel stiffener.

[0250] Another aspect of the invention relates to the use of a composition according to the invention as described above or of a reinforced structural member according to the invention as described above in the manufacture of a vehicle.

[0251] The following examples further illustrate the invention but are not to be construed as limiting its scope.

[0252] Curable one-component adhesive compositions were manufactured comprising the following ingredients at the following weight contents. The compositions were applied to a substrate and washout resistance and aging resistance were tested:

AF: adhesive failure; CF: cohesive failure; n.d.: not determined

[0253] As demonstrated by the above comparative data, loss of lap shear (A lap shear) is improved when the composition contains inosilicate in combination with metal oxide (Examples 3 and 5), even with comparatively low amounts of inosilicate (Examples 1 and 2 contain 14.69 wt.-% inosilicate, whereas Example 5 contains only 9.79 wt.-% inosilicate).

[0254] Wash-out resistance was tested in accordance with BMW standard AA-0044 from January 2018: Adhesive composition 8 was applied to a hot dip galvanized steel panel (DX54D+Z100, 200 x 40 mm) with an oil layer (PL3802-39S, 1.5 g/m ² = 0.12 g). The adhesive bead was applied to the base panel. The sample had no top panel, only a base panel on which the material was extruded to a defined thickness regarding the final application. The adhesive was not pre-cured. The prepared sample was placed in an immersion jig and dropped unimpeded from a height of 20 cm into a water tank filled with water at room temperature. Then the sample was mounted into a stirrer in a second water tank preheated to 60°C. Stirring was performed for 3 minutes at a velocity of 140 rpm (1.47m/s).

[0255] Aging resistance (A lap shear [%] (after 7 d)) was tested with a humid cataplasma test in accordance with PSA D47 1165 on 3 -point bending and lap shear samples. For lap shear samples, two substrates (HX 420 LAD 100) were adhesively bonded to one another at a gap of 4 mm with the adhesive compositions 1 to 5. Curing of the adhesives was performed at 165°C for 30 minutes. For 3 point bending samples, a 1 ,25mm thick material was adhered on a 0.7mm thin substrate and cured at 165°C for 30 minutes. For humid cataplasma, the samples were covered by cotton and then placed in a bag. The same weight of water and cotton was added, then the bag was sealed and put in an oven at 70°C for various duration. After this step, the samples were placed for 2 hours at -20°C, then kept at room temperature (23 °C) to warm and reach room temperature. The samples were tested in an interval of 2 to 4 hours. After immersing the test specimens to humid cataplasma for various duration at 70°C, lap shear strength was measured at 23°C according to ASTM method D 1002, 3 point bending was measured at 23°C according to PSA standard D45 2025.