WO2024015163A1

WO2024015163A1 - Adhesive composition

Info

Publication number: WO2024015163A1
Application number: PCT/US2023/024257
Authority: WO
Inventors: Eric Cole; Tyler AUVIL
Original assignee: Ddp Specialty Electronic Materials Us, Llc
Priority date: 2022-07-14
Filing date: 2023-06-02
Publication date: 2024-01-18

Abstract

Provided herein is a two-component acrylic-epoxy adhesive composition.

Description

ADHESIVE COMPOSITION Field of Invention The present invention relates to the field of epoxy-acrylic adhesive 5 compositions. Background of the Invention In the automotive industry, adhesives are used in the assembly of various components in which these components are bonded to each other or to other 10 parts of the vehicle. In the assembly process of closures (doors, hood and deck lids), some manufacturers require the adhesive to obtain handling strength via a room temperature curing process 15 minutes before the parts enter the high heat of the E-Coat ovens which can cause part distortion of the panels that are not securely bonded. The adhesive joint must also withstand 15 the high heat of the paint and E-Coat ovens during the assembly of the vehicle. It is a growing trend among automotive manufacturers to consider hem flange joints to be a crash critical component of the vehicle. This is due to crash 20 tests and real-world crash events where closures with adhesively bonded hem flange joints have unzipped or separated during a high-speed crash event. Therefore, room-temperature curing adhesives with heat resistance and impact peel strength are required for the closure application. Typically, the adhesive chemistry is an epoxy-acrylic hybrid in order to attain rapid cure and 25 heat resistance. However, these systems are usually quite brittle and don’t afford the required impact peel strengths. Historically, several families of reactive and non-reactive tougheners have been used in epoxy acrylic hybrid adhesives. One of the most effective and 30 popular reactive tougheners is methacrylate terminated butadiene rubber or methacrylate terminated butadiene acrylonitrile rubber. While this family of reactive tougheners is very effective at imparting impact resistance, they have a very poor supply chain position in that there is only one source of their manufacturing globally. In addition, the manufacturing of these materials is hazardous with negative environmental effects. A need remains for acrylic-epoxy hybrid adhesives that show good impact 5 peel resistance after e-coat exposure. Summary of the Invention In a first aspect, the invention provides a two-component epoxy-acrylic hybrid adhesive, comprising: 10 Part A ai) at least one methacrylate monomer; aii) at least one methacrylate-terminated toughener having a Tg of 0^oC or less; aiii) a phosphorus-containing compound selected from mono-esters of 15 phosphonic, mono- and di-esters of phosphonic and phosphoric acids having one unit of vinyl or allylic unsaturation present; aiv) a tertiary amine radical initiator; Part B bi) at least one epoxy resin; 20 bii) an oxidizing agent. In a second aspect, the invention provides a method for adhering two or more substrates, comprising the steps: (1) providing a two-component epoxy hybrid adhesive, comprising 25 Part A ai) at least one methacrylate monomer; aii) at least one methacrylate-terminated toughener having a T_g of 0^oC or less; aiii) a phosphorus-containing compound selected from mono-esters of 30 phosphonic, mono- and di-esters of phosphonic and phosphoric acids having one unit of vinyl or allylic unsaturation present; aiv) a tertiary amine radical initiator; Part B bi) at least one epoxy resin; bii) an oxidizing agent; (2) mixing Part A and Part B to obtain an adhesive mixture; (3) applying the adhesive mixture to a first substrate, a second substrate or both; 5 (4) bringing the first substrate and the second substrate into adhesive contact; and (5) allowing the adhesive mixture to cure. Detailed Description of the Invention 10 The inventors have found that it is possible to achieve an epoxy-acrylic adhesive having rapid curing at room temperature while having excellent impact peel strength, even after exposure to high-temperature conditions. Definitions and abbreviations 15 MDI 4,4′-Methylenebis(phenyl isocyanate) HDI Hexamethylene diisocyanate HEMA hydroxyethylmethacrylate IPDI isophorone diisocyanate PTMEG poly(tetramethylene oxide) glycol 20 PU polyurethane SEC size exclusion chromatography RH relative humidity CF cohesive failure AF adhesive failure 25 Mp peak molecular weight, the molecular weight of the highest peak FTIR Fourier transform infrared DMA Dynamic mechanical analysis 30 Equivalent and molecular weights are measured by gel permeation chromatography (GPC) using the method and equipment recited in the Examples section. At least one methacrylate monomer (ai) Part A of the adhesive comprises at least one methacrylate monomer. The methacrylate monomer is not particularly limited. Examples include monomers having the general structure of Formula I:

5 where R is an organic radical. In preferred embodiments, R is selected from H, a C₁-C₁₈ substituted or unsubstituted cyclic or noncyclic aliphatic hydrocarbon radical, which may contain one or more heteroatoms, and a C₄-C₁₈ aromatic hydrocarbon radical, 10 which may contain one or more heteroatoms. More preferably, R is selected from a C1-C18 substituted or unsubstituted, cyclic or noncyclic aliphatic hydrocarbon radical, which may contain one or more heteroatoms, in particular R is cyclohexyl or CH2-THF, where THF is a 15 2- or 3-tetrahydrofurfuryl radical. Other examples of methacrylate monomers include isobornyl methacrylate, cyclohexyl methacrylate, methyl methacrylate, and mixtures of these. 20 In some embodiments, Part A comprises two or more methacrylate monomers. In a preferred embodiment, Part A comprises tetrahydrofurfuryl methacrylate (CAS [2455-24-5]). 25 In another preferred embodiment, Part A comprises cyclohexyl methacrylate (CAS [101-43-9]. In another preferred embodiment, Part A comprises a divalent metal salt of 30 methacrylic acid, in particular zinc dimethacrylate. In a particularly preferred embodiment, Part A comprises tetrahydrofurfuryl methacrylate and cyclohexyl methacrylate. 5 In another particularly preferred embodiment, Part A comprises tetrahydrofurfuryl methacrylate, cyclohexyl methacrylate, and a divalent metal salt of methacrylic acid, in particular zinc dimethacrylate. The methacrylate monomer or monomers preferably represent 28-45 wt%, 10 more preferably 30-38 wt% of Part A, based on the total weight of Part A. In a preferred embodiment, Part A comprises 25-35 wt%, more preferably 28- 32 wt% tetrahydrofurfuryl methacrylate, based on the total weight of Part A. 15 In another preferred embodiment, Part A comprises 2-10 wt%, more preferably 3-6 wt% cyclohexyl methacrylate, based on the total weight of Part A. In another preferred embodiment, Part A comprises 0.5-4 wt%, more 20 preferably 0.75-1.5 wt% of a divalent metal salt of methacrylic acid, based on the total weight of Part A. In another preferred embodiment, Part A comprises 0.5-4 wt%, more preferably 0.75-1.5 wt% of zinc dimethacrylate, based on the total weight of 25 Part A. In a particularly preferred embodiment, Part A comprises 25-35 wt%, more preferably 28-32 wt% tetrahydrofurfuryl methacrylate, and 2-10 wt%, more preferably 3-6 wt% cyclohexyl methacrylate, based on the total weight of Part 30 A. In another particularly preferred embodiment, Part A comprises 25-35 wt%, more preferably 28-32 wt% tetrahydrofurfuryl methacrylate, 2-10 wt%, more preferably 3-6 wt% cyclohexyl methacrylate, and 0.5-4 wt%, more preferably 0.75-1.5 wt% of zinc dimethacrylate, based on the total weight of Part A. At least one toughener (aii) 5 Part A comprises at least one methacrylate-terminated toughener having a Tg of 0^oC or less. In a preferred embodiment, the toughener comprises at least one polyether as part of its backbone. 10 In a preferred embodiment, the toughener has a Tg or 120^oC or less, more preferably -40^oC or less. In a preferred embodiment, the at least one toughener comprises or consists 15 of a toughener that is prepared by reacting a polyether polyol with a polyisocyanate in a ratio such that the resulting polymer is an NCO-capped polymer, followed by end-capping with a hydroxyalkyl ester of methacrylic acid. 20 The polyether polyol is not particularly limited. It may be a diol or triol, with diols being preferred. In a preferred embodiment, the polyol is a poly(C₂-C₆-alkylene oxide) diol, with C2, C3 and C4 being preferred, and C4 being particularly preferred [i.e. 25 poly(tetramethylene oxide)glycol or PTMEG]. In another preferred embodiment, the polyether polyol is selected from PTMEG’s having molecular weights from 1,000 to 3,000 Da, more preferably 2,000 Da. 30 The toughener may also comprise a low molecular weight (< 250 Da) polyol having functionality of 3 or 4, such as trimethylol propane. If present, the low molecular weight polyol is preferably used at 0.1-3 wt%, more preferably 0.25- 1 wt%, particularly preferably 0.5 wt%, based on the total weight of the toughener. In a preferred embodiment, the toughener comprises trimethylol propane at 0.1-3 wt%, more preferably 0.25-1 wt%, particularly preferably 0.5 wt%, based on the total weight of the toughener. 5 The polyisocyanate is not particularly limited. It may be aliphatic or aromatic, with aliphatic being preferred. The polyisocyanate is preferably a diisocyanate. 10 In a preferred embodiment, the polyisocyanate is an aliphatic diisocyanate. Examples include hexamethylene diisocyanate (HDI), isophorone diisocyanate, methylene dicyclohexyl diisocyanate. In a preferred embodiment, the polyether polyol is a diol, and the 15 polyisocyanate is a diisocyanate. In another preferred embodiment, the polyether polyol is an aliphatic diol, and the polyisocyanate is an aliphatic diisocyanate. 20 In another preferred embodiment, the polyether polyol is PTMEG and the polyisocyanate is HDI. The hydroxyalkyl ester of methacrylic acid is preferably a C₂-C₆-hydroxyalkyl ester, more preferably C2-C4-hydroxyalkyl, even more preferably C2-C3- 25 hydroxyalkyl, with C2-hydroxyalkyl being the most preferred, in particular hydroxyethyl methacrylate (HEMA): . The toughener is preferably made by reacting the polyether polyol with the polyisocyanate, in the presence of a polyurethane catalyst to produce an NCO-terminated prepolymer. The prepolymer is then reacted with a hydroxyalkyl ester of methacrylic acid, resulting in end-capping. In a preferred embodiment, the toughener is made by reacting PTMEG with 5 HDI, in the presence of a polyurethane catalyst to produce an NCO- terminated prepolymer. The prepolymer is then reacted with HEMA, resulting in end-capping. The resulting toughener is of the general Formula II:

where x has a value between 13 and 42, more preferably 27.8 (this 10 corresponds to a PTMEG of molecular weight 1,000 to 3,000 Da, more preferably 2,000 Da), and y has values of 1.5 to 5 or 1.8 to 4.9, more preferably 2.6. In a preferred embodiment, the toughener is of the general Formula II, having 15 a number average molecular weight (Mn) of 6,119 Da, as determined by gel permeation chromatography (GPC), according to the method recited in the Examples section. In a preferred embodiment, the toughener is of general Formula II, the 20 PTMEG has a molecular weight of 2,000 Da, and the toughener has a number average molecular weight (M_n) of 6,119 Da, as determined by gel permeation chromatography (GPC), according to the method recited in the Examples section. 25 In a preferred embodiment, the toughener is of the general Formula II, having a weight average molecular weight (Mw) of 15,084 Da, as determined by gel permeation chromatography (GPC), according to the method recited in the Examples section. 30 In a preferred embodiment, the toughener is of general Formula II, the PTMEG has a molecular weight of 2,000 Da, and the toughener has a weight average molecular weight (Mw) of 15,084 Da, as determined by gel permeation chromatography (GPC), according to the method recited in the Examples section. 5 In a preferred embodiment, Part A comprises 10-30 wt%, more preferably 15- 25 wt%, particularly preferably 17-22 wt% of toughener (aii), based on the total weight of Part A. In another preferred embodiment, Part A comprises 10-30 wt%, more 10 preferably 15-25 wt%, particularly preferably 17-22 wt% of toughener (aii), based on the total weight of Part A, wherein the toughener is made by reacting an aliphatic polyether diol with an aliphatic diisocyanate. In another preferred embodiment, Part A comprises 10-30 wt%, more 15 preferably 15-25 wt%, particularly preferably 17-22 wt% of toughener (aii), based on the total weight of Part A, wherein the toughener is made by reacting an aliphatic polyether diol with an aliphatic diisocyanate, followed by end-capping with a C2-C6-hydroxyalkyl ester, more preferably C2-C4- hydroxyalkyl, even more preferably C₂-C₃-hydroxyalkyl ester of methacrylic 20 acid, with C₂-hydroxyalkyl being the most preferred (hydroxyethyl methacrylate, HEMA). In another preferred embodiment, Part A comprises 10-30 wt%, more preferably 15-25 wt%, particularly preferably 17-22 wt% of toughener (aii), 25 based on the total weight of Part A, wherein the toughener is made by reacting PTMEG with HDI, followed by end-capping with a C₂-C₆-hydroxyalkyl ester, more preferably C₂-C₄-hydroxyalkyl, even more preferably C₂-C₃- hydroxyalkyl ester of methacrylic acid, with C2-hydroxyalkyl being the most preferred (hydroxyethyl methacrylate, HEMA). 30 In another preferred embodiment, Part A comprises 10-30 wt%, more preferably 15-25 wt%, particularly preferably 17-22 wt% of toughener (aii), based on the total weight of Part A, wherein the toughener is made by reacting PTMEG with HDI, followed by end-capping with HEMA. In another preferred embodiment, Part A comprises 10-30 wt%, more preferably 15-25 wt%, particularly preferably 17-22 wt% of toughener (aii), wherein the toughener is of Formula II: 5 where x has a value between 13 and 42, more preferably 27.73 (this corresponds to a PTMEG of molecular weight 1,000 to 3,000 Da, more preferably 2,000 Da), and y has values of 1.5 to 5 or 1.8 to 4.9, more preferably 2.6. 10 Phosphorus-containing compound (aiii) Part A comprises a phosphorus-containing compound selected from mono- esters of phosphonic, mono- and di-esters of phosphonic and mono-, di- and tri-esters of phosphoric acid having one unit of vinyl or allylic unsaturation 15 present. Preferably the phosphorus-containing compound (aiii) is of the Formulae III, IV and V:

20 where W is the same or different, and each W is independently selected from H, and a divalent organic radical, with at least one W being a divalent organic radical, and at least one X is a vinyl group, and the other(s) is(are) a vinyl group or absent (in case W is H), or H. 25 In another preferred embodiment, the phosphorus-containing compound (aiii) is of Formula V. In another preferred embodiment, the phosphorus-containing compound (aiii) is of Formula V and one, two or three X groups are vinyl. Preferably one X group is vinyl. 5 In another preferred embodiment, the phosphorus-containing compound (aiii) is of Formula V and one, two or three WX groups are of the Formula VI: where the dot represents the point of radical attachment. In the case where one or two WX groups are of Formula VI, the remaining WX group(s) is(are) 10 preferably H. In a particularly preferred embodiment, one WX group is of Formula VI, and the remaining WX groups are H, yielding the Formula VII: In another particularly preferred embodiment, two WX groups are of the Formula VI, and the remaining WX group is H, yielding the Formula VIII:

15 In another preferred embodiment, the phosphorus-containing compound (aiii) is an approximate 2:1 mixture of Formula VII and Formula VIII. Other examples of the phosphorus-containing compound include, without20 limitation, phosphoric acid; 2-methacryloyloxyethyl phosphate; bis-(2- methacryloxyloxyethyl)phosphate; 2-acryloyloxyethyl phosphate; bis-(2- acryloyloxyethyl)phosphate; methyl-(2-methacryloyloxyethyl)phosphate; ethyl methacryloyloxyethyl phosphate; methyl acryloyloxyethyl phosphate; ethyl acryloyloxyethyl phosphate; propyl acryloyloxyethyl phosphate, isobutyl acryloyloxyethyl phosphate, ethylhexyl acryloyloxyethyl phosphate, halopropyl acryloyloxyethyl phosphate, haloisobutyl acryloyloxyethyl phosphate or haloethylhexyl acryloyloxyethyl phosphate; vinyl phosphonic acid; cyclohexene-3-phosphonic acid; (α-hydroxybutene-2 phosphonic acid; 1- 5 hydroxy-1-phenylmethane- 1,1-diphosphonic acid; 1-hydroxy- 1-methyl-1- disphosphonic acid: 1-amino-1phenyl-1,1-diphosphonic acid; 3-amino-3- hydroxypropane-1,1-disphosphonic acid; amino-tris(methylenephosphonic acid); gamma-amino-propylphosphonic acid; gamma- glycidoxypropylphosphonic acid; phosphoric acid-mono-2-aminoethyl ester; 10 allyl phosphonic acid; allyl phosphinic acid; β-methacryloyloxyethyl phosphinic acid; diallylphosphinic acid; β-methacryloyloxyethyl)phosphinic acid and allyl methacryloyloxyethyl phosphinic acid. Preferred phosphorus compounds are 2-hydroxyethylmethacrylate phosphate and phosphonated (meth)acrylic monomer. 15 Tertiary amine radical initiator (aiv) Part A comprises a tertiary amine radical initiator. The tertiary amine radical initiator is not particularly limited. 20 Preferred tertiary amine radical initiators are of the general Formula IX: wherein W is selected from the group consisting of hydrogen, hydroxy, amino, halogen, alkyl having 1 to 8, preferably 1 to 4, carbon atoms, and alkoxy having 1 to 8, preferably 1 to 4, carbon atoms; R¹ and R² are independently 25 selected from branched or linear C_1-4-alkyl; and b is 1 or 2. Examples include N,N-dimethyl aniline, N,N-dimethylaminomethylphenol and N,N-dimethyl-p-toluidine In a particularly preferred embodiment, the tertiary amine radical initiator is N,N-dimethyl-p-toluidine. At least one epoxy resin (bi) 5 Part B comprises at least one epoxy resin. Suitable epoxy resins include the diglycidyl ethers of polyhydric phenol compounds such as resorcinol, catechol, hydroquinone, bisphenol, bisphenol A, bisphenol AP (1,1- bis(4-hydroxylphenyl)-1-phenyl ethane), bisphenol F, 10 bisphenol K, bisphenol M, tetramethylbiphenol, diglycidyl ethers of aliphatic glycols and polyether glycols such as the diglycidyl ethers of C2-24 alkylene glycols and poly(ethylene oxide) or poly(propylene oxide) glycols; polyglycidyl ethers of phenol-formaldehyde novolac resins, alkyl substituted phenol formaldehyde resins (epoxy novalac resins), phenolhydroxybenzaldehyde 15 resins, cresol-hydroxybenzaldehyde resins, dicyclopentadiene-phenol resins and dicyclopentadiene- substituted phenol resins, and any combination thereof. Suitable diglycidyl ethers include diglycidyl ethers of bisphenol A resins such as are sold by Olin Corporation under the designations D.E.R.^®330, D.E.R.^®331, D.E.R.^®332, D.E.R.^®383, D.E.R.^®661 and 20 D.E.R.^®662 resins. In a preferred embodiment, the at least one epoxy resin comprises a reaction product of epichlorohydrin and bisphenol A. 25 In another preferred embodiment, the at least one epoxy resin comprises a liquid reaction product of epichlorohydrin and bisphenol A. In a preferred embodiment, the at least one epoxy resin comprises an epoxy resin that is a liquid reaction product of epichlorohydrin and bisphenol A, 30 having an epoxide equivalent weight of 182-192 g/eq (as measured according to ASTM D-1652), an epoxide percentage of 22.4-23.6 % (as measured according to ASTM D-1652), an epoxide group content of 5,200-5,500 mmol/kg (as measured according to ASTM D-1652), and a viscosity at 25^oC of 11,000-14,000 mPas (as measured according to ASTM D-445). In another preferred embodiment, the at least one epoxy resin comprises a bisphenol A-based epoxy resin with an epoxy equivalent weight of approximately 352.5 g/equivalent. 5 In a particularly preferred embodiment, the at least one epoxy resin comprises a mixture of a liquid reaction product of epichlorohydrin and bisphenol A, having an epoxide equivalent weight of 182-192 g/eq (as measured according to ASTM D-1652), an epoxide percentage of 22.4-23.6 % (as measured 10 according to ASTM D-1652), an epoxide group content of 5,200-5,500 mmol/kg (as measured according to ASTM D-1652), and a viscosity at 25^oC of 11,000-14,000 mPas (as measured according to ASTM D-445), and a bisphenol A-based epoxy resin with an epoxy equivalent weight of approximately 352.5 g/equivalent. 15 In a preferred embodiment, the at least one epoxy resin comprises 50-90 wt%, more preferably 60-80 wt% of a liquid reaction product of epichlorohydrin and bisphenol A, having an epoxide equivalent weight of 182- 192 g/eq (as measured according to ASTM D-1652), an epoxide percentage 20 of 22.4-23.6 % (as measured according to ASTM D-1652), an epoxide group content of 5,200-5,500 mmol/kg (as measured according to ASTM D-1652), and a viscosity at 25^oC of 11,000-14,000 mPas (as measured according to ASTM D-445), based on the total weight of epoxy resin in Part B. 25 In another preferred embodiment, the at least one epoxy resin comprises 10- 50 wt%, more preferably 20-40 wt% of a bisphenol A-based epoxy resin with an epoxy equivalent weight of approximately 352.5 g/equivalent, based on the total weight of epoxy resin in Part B. 30 In another preferred embodiment, the at least one epoxy resin comprises 50- 90 wt%, more preferably 60-80 wt% of a liquid reaction product of epichlorohydrin and bisphenol A, having an epoxide equivalent weight of 182- 192 g/eq (as measured according to ASTM D-1652), an epoxide percentage of 22.4-23.6 % (as measured according to ASTM D-1652), an epoxide group content of 5,200-5,500 mmol/kg (as measured according to ASTM D-1652), and a viscosity at 25^oC of 11,000-14,000 mPas (as measured according to ASTM D-445), and 10-50 wt%, more preferably 20-40 wt% of a bisphenol A- based epoxy resin with an epoxy equivalent weight of approximately 352.5 5 g/equivalent, based on the total weight of epoxy resin in Part B. Part B preferably comprises the at least one epoxy resin comprises from 20 to 80 wt%, more preferably 20 to 60 wt%, more particularly preferably 25 to 40 wt% of epoxy resin, based on the total weight of Part B. 10 Oxidizing agent (bii) Part B comprises an oxidizing agent. The oxidizing agent is not particularly limited. 15 Representative oxidizing agents including, without limitation, organic peroxides, such as benzoyl peroxide and other diacyl peroxides, hydroperoxides such as cumene hydroperoxide, peresters such as β- butylperoxybenzoate; ketone hydroperoxides such as methyl ethyl ketone hydroperoxide, organic salts of transition metals such as cobalt naphthenate, 20 and compounds containing a labile chlorine such as sulfonyl chloride. The most preferred oxidizing agent is benzoyl peroxide. The oxidizing agent, preferably organic peroxide, is preferably present in Part B at 3-10 wt%, more preferably 5-9 wt%, based on the total weight of Part B. 25 In a preferred embodiment, Part B comprises benzoyl peroxide at 3-10 wt%, more preferably 5-9 wt%, based on the total weight of Part B. Optional ingredients 30 The adhesives of the invention may contain additional optional ingredients, such as, for example: Stabilizers/free-radical scavengers may be added to both Part A and Part B, to extend shelf-life of the unmixed parts. Examples of stabilizers/free-radical scavengers include 1, 3, 5-TRIMETHYL-2,4,6-TRIS (3,5-DI-TERT-BUTYL-4- HYDROXYBENZYL) BENZENE, di-ethylhydroxy amine (DEHA), butylated hydroxy toluene (BHT), methyl ether of hydroquinone, hydroquinone, benzoquinone, naphthoquinone, hydroxyl amine, and nitrile oxides. 5 Fillers such as wollastonite, talc, fumed silica, calcium carbonate and glass. Part A may optionally comprise cross-linkers, such as divalent metal salts of methacrylic acid, such as zinc dimethacrylate, calcium dimethacrylate, 10 magnesium dimethacrylate, or mixtures of these. Part A may optionally comprise an additional toughener. Suitable additional tougheners are rubber based, such as acrylate-based tougheners, butadiene- based tougheners, acrylonitrile-butadiene-based tougheners, chlorinated or 15 chlorosulphonated polyethylenes, block copolymers of styrene and conjugated dienes (SBS, SIS), ethylene acrylic elastomers, core-shell graft copolymers. In a preferred embodiment, Part A comprises a rubber-based toughener. 20 In another preferred embodiment, part A comprises a rubber-based toughener selected from acrylate-based tougheners, butadiene-based tougheners, acrylonitrile-butadiene-based tougheners, chlorinated or chlorosulphonated polyethylenes, block copolymers of styrene and conjugated dienes (SBS, 25 SIS), ethylene acrylic elastomers, core-shell graft copolymers. In another preferred embodiment, Part A comprises a rubber-based toughener that is a copolymer of 2-propeneoic acid, 2-methyl-, methyl ester with 1,3-butadiene. 30 If used, the additional rubber-based toughener is preferably used in Part A at 2-24 wt%, more preferably 7.5-18.5 wt%, more particularly preferably 10- 15.75 wt%, based on the total weight of Part A. In a preferred embodiment, Part A comprises a rubber-based toughener, used at 2-24 wt%, more preferably 7.5-18.5 wt%, more particularly preferably 10- 15.75 wt%, based on the total weight of Part A. 5 In another preferred embodiment, part A comprises a rubber-based toughener selected from acrylate-based tougheners, butadiene-based tougheners, acrylonitrile-butadiene-based tougheners, chlorinated or chlorosulphonated polyethylenes, block copolymers of styrene and conjugated dienes (SBS, SIS), ethylene acrylic elastomers, core-shell graft copolymers, used at 2-24 10 wt%, more preferably 7.5-18.5 wt%, more particularly preferably 10-15.75 wt%, based on the total weight of Part A In another preferred embodiment, Part A comprises a rubber-based toughener that is a copolymer of 2-propeneoic acid, 2-methyl-, methyl ester 15 with 1,3-butadiene, used at 2-24 wt%, more preferably 7.5-18.5 wt%, more particularly preferably 10-15.75 wt%, based on the total weight of Part A. Additional optional ingredients may include, for example, adhesion promoters, pigments, thixotropic agents, wetting agents, reactive diluents, antioxidants, 20 inhibitors, and stabilizers. Method of manufacture The at least one toughener is manufactured by a method comprising the steps: 25 (1) mixing a polyetherpolyol and a polyisocyanate; (2) adding a catalyst capable of catalyzing the reaction of a hydroxyl group with an isocyanate group, to form an isocyanate terminated prepolymer; AND (3) reacting the isocyanate prepolymer is then reacted with a hydroxyalkyl ester of methacrylic acid, such that the isocyanate groups are capped with the 30 hydroxyalkyl ester of methacrylic acid. The reactions in steps (2) and (3) are typically carried out under vacuum or under a neutral atmosphere, such as nitrogen or argon. Preferred polyetherpolyols are as listed under the description of the toughener. Preferred polyisocyanates are as listed under the description of the 5 toughener. Preferred hydroxyalkyl esters of methacrylic acid are as listed under the description of the toughener. 10 The catalyst is preferably selected from Lewis bases and Lewis acids. Suitable catalysts include tertiary amines, including diazabicyclo[2.2.2]octane, 2,4,6-tris((dimethylamino)methyl)phenol, DMDEE (2,2'- Dimorpholinodiethylether), imidazoles, such as 4-methylimidazole), triethanolamine, and organometallic catalysts, in particular organotin 15 compounds, such as dibutyl tin dilaurate, dioctyltindineodecanoate, and other metal catalysts such as tetrabutyltitanate, zirconium acetylacetonate, and bismuthneodecanoate. Dibutyl tin dilaurate is particularly preferred. 20 Method of use In use, the adhesive Part A and Part B are mixed to homogeneity and applied immediately. The mixing ratio of Part A to Part B is preferably 2:1 to 10:1, with 3:1 being particularly preferred. 25 Suitable substrates include, for example, electrogalvanized steel, hot dipped galvanized steel, cold rolled steel, aluminium. Effect of the invention 30 The adhesives of the invention show good impact peel strength, particularly when measured according to ISO 11343. In a preferred embodiment, the adhesives show an impact peel strength of at least 15 N/mm, more preferably at least 20 N/mm, when measured according to ISO 11343, using electrogalvanized steel as substrate, with a bond area of 20 X 30 mm, with a 10 mil bond gap, and curing for 1 day at 23^oC, followed by 45 minutes at 190^oC. 5 The adhesives of the invention preferably show at least 90% cohesive failure mode when tested according to ISO 11343, on electrogalvanized steel, after curing for 1 day at 23^oC, followed by 45 minutes at 190^oC. The adhesives of the invention preferably show a lap shear strength of at 10 least 10 MPa, more preferably at least 11 MPa, when measured according to ISO 4587 using electrogalvanized steel as substrate with a ½ square inch overlap as bond area, a 10 mil bond gap, and curing for 16 hours at 23^oC and 45 minutes at 190^oC. 15 The adhesives of the invention preferably show at least 90% cohesive failure mode when tested according to ISO 4587 on electrogalvanized steel, after curing for 16 hours at 23^oC, followed by 45 minutes at 190^oC. Applications 20 The adhesives of the invention are particularly suited to automotive applications in which relatively quick cure is required and in which the bonded part will subsequently be exposed to e-coat conditions. Particularly preferred embodiments 25 The following are particularly preferred embodiments of the invention: 1. A two-component epoxy-acrylic hybrid adhesive, comprising: Part A ai) at least one methacrylate monomer; 30 aii) at least one methacrylate-terminated toughener having a T_g of 0^oC or less; aiii) a phosphorus-containing compound selected from mono- esters of phosphonic, mono- and di-esters of phosphonic and phosphoric acids having one unit of vinyl or allylic unsaturation present; aiv) a tertiary amine radical initiator; Part B 5 bi) at least one epoxy resin; bii) an oxidizing agent. 2. A method for adhering two or more substrates, comprising the steps: (1) providing a two-component epoxy hybrid adhesive, comprising 10 Part A ai) at least one methacrylate monomer; aii) at least one methacrylate-terminated toughener having a Tg of 0^oC or less; aiii) a phosphorus-containing compound selected from mono- 15 esters of phosphonic, mono- and di-esters of phosphonic and phosphoric acids having one unit of vinyl or allylic unsaturation present; aiv) a tertiary amine radical initiator; Part B 20 bi) at least one epoxy resin; bii) an oxidizing agent; (2) mixing Part A and Part B to obtain an adhesive mixture; (3) applying the adhesive mixture to a first substrate, a second substrate or both; 25 (4) bringing the first substrate and the second substrate into adhesive contact; and (5) allowing the adhesive mixture to cure. 3. Embodiment 1 or 2, wherein the at least one toughener has a T_g of - 30 20^oC or less, when measured by DMA. 4. Embodiment 1, 2 or 3, wherein the toughener has a Tg of -40^oC or less, when measured by DMA. 5. Any one preceding embodiment, wherein the at least one toughener comprises or consists of a toughener prepared from a polyetherpolyol reacted with a polyisocyanate, followed by end-capping with a hydroxyalkyl ester of methacrylic acid. 5 6. Any one preceding embodiment, wherein the at least one methacrylate monomer (ai) comprises a molecule of the general structure of Formula I:

10 where R is an organic radical. 7. Any one preceding embodiment, wherein Part A additionally comprises one or more divalent metal salts of methacrylic acid, preferably zinc dimeythacrylate. 15 8. Embodiment 6, wherein R is selected from H, a C₁-C₁₈ substituted or unsubstituted cyclic or noncyclic aliphatic hydrocarbon radical, which may contain one or more heteroatoms, and a C4-C18 aromatic hydrocarbon radical, which may contain one or more heteroatoms. 20 9. Embodiment 6, wherein R is selected from a C1-C18 substituted or unsubstituted, cyclic or noncyclic aliphatic hydrocarbon radical, which may contain one or more heteroatoms, in particular R is cyclohexyl or CH2-THF, where THF is a 2- or 3-tetrahydrofurfuryl radical. 25 10. Any one preceding embodiment, wherein Part A comprises two or more methacrylate monomers. 11. Any one preceding embodiment, wherein the at least one methacrylate 30 monomer comprises tetrahydrofurfuryl methacrylate. 12. Any one preceding embodiment, wherein the at least one methacrylate monomer comprises cyclohexyl methacrylate. 5 13. Any one preceding embodiment, wherein Part A additionally comprises a divalent metal salt of methacrylic acid, in particular zinc dimethacrylate. 14. Any one preceding embodiment, wherein the at least one methacrylate monomer comprises tetrahydrofurfuryl methacrylate and cyclohexyl 10 methacrylate. 15. Any one preceding embodiment, wherein the at least one methacrylate monomer comprises tetrahydrofurfuryl methacrylate and cyclohexyl methacrylate. 15 16. Any one preceding embodiment, wherein the methacrylate monomer or monomers represents 25-35 wt%, more preferably 28-32 wt% tetrahydrofurfuryl methacrylate, based on the total weight of Part A. 20 17. Any one preceding embodiment, wherein Part A comprises 25-35 wt%, more preferably 28-32 wt% tetrahydrofurfuryl methacrylate, based on the total weight of Part A. 18. Any one preceding embodiment, wherein Part A comprises 2-10 wt%, 25 more preferably 3-6 wt% cyclohexyl methacrylate, based on the total weight of Part A. 19. Any one preceding embodiment, wherein Part A comprises 0.5-4 wt%, more preferably 0.75-1.5 wt% of a divalent metal salt of methacrylic acid, 30 based on the total weight of Part A. 20. Any one preceding embodiment, wherein Part A comprises 0.5-4 wt%, more preferably 0.75-1.5 wt% of zinc dimethacrylate, based on the total weight of Part A. 21. Any one preceding embodiment, wherein Part A comprises 25-35 wt%, more preferably 28-32 wt% tetrahydrofurfuryl methacrylate, and 2-10 wt%, more preferably 3-6 wt% cyclohexyl methacrylate, based on the 5 total weight of Part A. 22. Any one preceding embodiment, wherein Part A comprises 25-35 wt%, more preferably 28-32 wt% tetrahydrofurfuryl methacrylate, 2-10 wt%, more preferably 3-6 wt% cyclohexyl methacrylate, and 0.5-4 wt%, more 10 preferably 0.75-1.5 wt% of zinc dimethacrylate, based on the total weight of Part A. 23. Any one preceding embodiment, wherein the polyether polyol used to make the toughener is a diol or triol. 15 24. Any one preceding embodiment, wherein the polyether polyol used to make the toughener is a diol. 25. Any one preceding embodiment, wherein the polyether polyol used to 20 make the toughener is a poly(C₂-C₆-alkylene oxide) diol, with C₂, C₃ and C4 being preferred, and C4 being particularly preferred [i.e. poly(tetramethylene oxide)glycol or PTMEG]. 26. Any one preceding embodiment, wherein the polyether polyol used to 25 make the toughener is selected from PTMEG’s having molecular weights from 1,000 to 3,000 Da, more preferably 2,000 Da. 27. Any one preceding embodiment, wherein the polyisocyanate used to make the toughener is aliphatic or aromatic. 30 28. Any one preceding embodiment, wherein the polyisocyanate used to make the toughener is aliphatic. 29. Any one preceding embodiment, wherein the polyisocyanate used to make the toughener is a diisocyanate. 30. Any one preceding embodiment, wherein the polyisocyanate used to 5 make the toughener is selected from hexamethylene diisocyanate (HDI), isophorone diisocyanate, and methylene dicyclohexyl diisocyanate. 31. Any one preceding embodiment, wherein the polyether polyol used to make the toughener is PTMEG and the polyisocyanate is HDI. 10 32. Any one preceding embodiment, wherein the hydroxyalkyl ester of methacrylic acid used to make the toughener is a C2-C6-hydroxyalkyl ester. 15 33. Any one preceding embodiment, wherein the hydroxyalkyl ester of methacrylic acid used to make the toughener is a C₂-C₄-hydroxyalkyl ester. 34. Any one preceding embodiment, wherein the hydroxyalkyl ester of 20 methacrylic acid used to make the toughener is a C₂-C₃-hydroxyalkyl ester. 35. Any one preceding embodiment, wherein the hydroxyalkyl ester of methacrylic acid used to make the toughener is hydroxyethyl 25 methacrylate, HEMA): . 36. Any one preceding embodiment, wherein the toughener is of the general Formula II: where x has a value between 13 and 42. 37. Embodiment 36, wherein x is 27.8. 5 38. Embodiment 36 or 37, wherein y has values of 1.5 to 5. 39. Any one of embodiments 36 to 38, wherein y has values of 1.8 to 4.9. 10 40. Any one of embodiments 36 to 39, wherein y is 2.6. 41. Any one preceding embodiment, wherein the toughener is of general Formula II, and has a number average molecular weight (Mn) of 6,119 Da, as determined by gel permeation chromatography (GPC), according 15 to the method recited in the Examples section. 42. Any one preceding embodiment, wherein the toughener is of general Formula II, and has a weight average molecular weight (Mw) of 15,084 Da, as determined by gel permeation chromatography (GPC), according 20 to the method recited in the Examples section. 43. Any one preceding embodiment, wherein Part A comprises 10-30 wt% toughener (aii), based on the total weight of Part A. 25 44. Any one preceding embodiment, wherein Part A comprises 15-25 wt% toughener (aii), based on the total weight of Part A. 45. Any one preceding embodiment, wherein Part A comprises 17-22 wt% of toughener (aii), based on the total weight of Part A. 30 46. Any one preceding embodiment, wherein the phosphorus-containing compound (aiii) is is of the Formulae III, IV and V:

where W is the same or different, and each W is independently selected 5 from H, and a divalent organic radical, with at least one W being a divalent organic radical, and at least one X is a vinyl group, and the other(s) is(are) a vinyl group or absent (in case W is H), or H. 47. Any one preceding embodiment, wherein the phosphorus-containing 10 compound (aiii) is of Formula V. 48. Any one preceding embodiment, wherein the phosphorus-containing compound (aiii) is of Formula V and one, two or three X groups are vinyl. 15 49. Any one preceding embodiment, wherein the phosphorus-containing compound (aiii) is of Formula V and one X group is vinyl. 50. Any one preceding embodiment, wherein the phosphorus-containing compound (aiii) is of Formula V and one, two or three WX groups are of 20 the Formula VI: where the dot represents the point of radical attachment. 51. Embodiment 50, wherein one or two WX groups are of Formula VI, and 25 the remaining WX group(s) is(are) H. 52. Any one preceding embodiment, wherein the phosphorus-containing compound comprises a molecule of Formula VII: . 53. Any one preceding embodiment, wherein the phosphorus-containing compound comprises a molecule of Formula VIII: 5 . 54. Any one preceding embodiment, wherein the phosphorus-containing compound (aiii) is an approximate 2:1 mixture of Formula VII and Formula VIII. 10 55. Any one preceding embodiment, wherein the tertiary amine radical initiator is N,N-dimethyl-p-toluidine. 56. Any one preceding embodiment, wherein the at least one epoxy resin 15 comprises a diglycidyl ether of a polyhydric phenol compound. 57. Any one preceding embodiment, wherein the at least one epoxy resin comprises a reaction product of bisphenol A and epichlorohydrin. 20 58. Any one preceding embodiment, wherein the at least one epoxy resin comprises a liquid reaction product of bisphenol A and epichlorohydrin. 59. Any one preceding embodiment, wherein the at least one epoxy resin comprises a liquid reaction product of epichlorohydrin and bisphenol A, 25 having an epoxide equivalent weight of 182-192 g/eq (as measured according to ASTM D-1652), an epoxide percentage of 22.4-23.6 % (as measured according to ASTM D-1652), an epoxide group content of 5,200-5,500 mmol/kg (as measured according to ASTM D-1652), and a viscosity at 25^oC of 11,000-14,000 mPas (as measured according to ASTM D-445). 5 60. Any one preceding embodiment, wherein the at least one epoxy resin comprises a bisphenol A-based epoxy resin with an epoxy equivalent weight of approximately 352.5 g/equivalent. 10 61. Any one preceding embodiment, wherein the at least one epoxy resin comprises a mixture of a liquid reaction product of epichlorohydrin and bisphenol A, having an epoxide equivalent weight of 182-192 g/eq (as measured according to ASTM D-1652), an epoxide percentage of 22.4- 23.6 % (as measured according to ASTM D-1652), an epoxide group15 content of 5,200-5,500 mmol/kg (as measured according to ASTM D- 1652), and a viscosity at 25^oC of 11,000-14,000 mPas (as measured according to ASTM D-445), and a bisphenol A-based epoxy resin with an epoxy equivalent weight of approximately 352.5 g/equivalent. 20 62. Any one preceding embodiment, wherein the at least one epoxy resin comprises 50-90 wt%, more preferably 60-80 wt% of a liquid reaction product of epichlorohydrin and bisphenol A, having an epoxide equivalent weight of 182-192 g/eq (as measured according to ASTM D- 1652), an epoxide percentage of 22.4-23.6 % (as measured according to 25 ASTM D-1652), an epoxide group content of 5,200-5,500 mmol/kg (as measured according to ASTM D-1652), and a viscosity at 25^oC of 11,000-14,000 mPas (as measured according to ASTM D-445), based on the total weight of epoxy resin in Part B. 30 63. Any one preceding embodiment, wherein the at least one epoxy resin comprises 10-50 wt%, more preferably 20-40 wt% of a bisphenol A- based epoxy resin with an epoxy equivalent weight of approximately 352.5 g/equivalent, based on the total weight of epoxy resin in Part B. 64. Any one preceding embodiment, wherein the at least one epoxy resin comprises 50-90 wt%, more preferably 60-80 wt% of a liquid reaction product of epichlorohydrin and bisphenol A, having an epoxide equivalent weight of 182-192 g/eq (as measured according to ASTM D- 5 1652), an epoxide percentage of 22.4-23.6 % (as measured according to ASTM D-1652), an epoxide group content of 5,200-5,500 mmol/kg (as measured according to ASTM D-1652), and a viscosity at 25^oC of 11,000-14,000 mPas (as measured according to ASTM D-445), and 10- 50 wt%, more preferably 20-40 wt% of a bisphenol A-based epoxy resin 10 with an epoxy equivalent weight of approximately 352.5 g/equivalent, based on the total weight of epoxy resin in Part B. 65. Any one preceding embodiment, wherein Part B comprises the at least one epoxy resin at from 20 to 80 wt%, more preferably 20 to 60 wt%, 15 more particularly preferably 25 to 40 wt% of epoxy resin, based on the total weight of Part B. 66. Any one preceding embodiment, wherein the oxidizing agent is an organic peroxide. 20 67. Any one preceding embodiment, wherein the oxidizing agent is selected from benzoyl peroxide and other diacyl peroxides, hydroperoxides such as cumene hydroperoxide, peresters such as β-butylperoxybenzoate; ketone hydroperoxides such as methyl ethyl ketone hydroperoxide, 25 organic salts of transition metals such as cobalt naphthenate, and compounds containing a labile chlorine such as sulfonyl chloride. 68. Any one preceding embodiment, wherein the organic peroxide is benzoyl peroxide. 30 69. Any one preceding embodiment, wherein the organic peroxide is present in Part B at 3-10 wt%, more preferably 5-9 wt%, based on the total weight of Part B. 70. Any one preceding embodiment, wherein Part B comprises benzoyl peroxide at 3-10 wt%, more preferably 5-9 wt%, based on the total weight of Part B. 5 71. Any one preceding embodiment, wherein Part A and/or Part B comprises stabilizers and/or radical stabilizers. 72. Any one preceding embodiment, wherein Part A and/or Part B comprises a stabilizer and/or radical scavenger selected from 1, 3, 5-TRIMETHYL-10 2,4,6-TRIS (3,5-DI-TERT-BUTYL-4-HYDROXYBENZYL) BENZENE, di- ethylhydroxy amine (DEHA), butylated hydroxy toluene (BHT), and mixtures of these. 73. Any one preceding embodiment, wherein Part A and/or Part(B) 15 comprises a filler selected from wollastonite, talc, fumed silica, calcium carbonate and mixtures of these. 74. Any one preceding embodiment, wherein Part A comprises an additional toughener. 20 75. Any one preceding embodiment, wherein Part A comprises an additional toughener that is rubber based, such as acrylate-based tougheners, butadiene-based tougheners, acrylonitrile-butadiene-based tougheners, chlorinated or chlorosulphonated polyethylenes, block copolymers of25 styrene and conjugated dienes (SBS, SIS), ethylene acrylic elastomers, core-shell graft copolymers. 76. Any one preceding embodiment, wherein Part A additionally comprises a rubber-based toughener. 30 77. Any one preceding embodiment, wherein part A additionally comprises a rubber-based toughener selected from acrylate-based tougheners, butadiene-based tougheners, acrylonitrile-butadiene-based tougheners, chlorinated or chlorosulphonated polyethylenes, block copolymers of styrene and conjugated dienes (SBS, SIS), ethylene acrylic elastomers, core-shell graft copolymers. 77. Any one preceding embodiment, wherein Part A additionally comprises a 5 rubber-based toughener that is a copolymer of 2-propeneoic acid, 2- methyl-, methyl ester with 1,3-butadiene. 78. Any one preceding embodiment, wherein the additional rubber-based toughener is used in Part A at 2-24 wt%, more preferably 7.5-18.5 wt%,10 more particularly preferably 10-15.75 wt%, based on the total weight of Part A. 79. Any one preceding embodiment, wherein Part A additionally comprises a rubber-based toughener, used at 2-24 wt%, more preferably 7.5-18.515 wt%, more particularly preferably 10-15.75 wt%, based on the total weight of Part A. 80. Any one preceding embodiment, wherein part A additionally comprises a rubber-based toughener selected from acrylate-based tougheners,20 butadiene-based tougheners, acrylonitrile-butadiene-based tougheners, chlorinated or chlorosulphonated polyethylenes, block copolymers of styrene and conjugated dienes (SBS, SIS), ethylene acrylic elastomers, core-shell graft copolymers, used at 2-24 wt%, more preferably 7.5-18.5 wt%, more particularly preferably 10-15.75 wt%, based on the total25 weight of Part A 81. Any one preceding embodiment, wherein Part A comprises a rubber- based toughener that is a copolymer of 2-propeneoic acid, 2-methyl-, methyl ester with 1,3-butadiene, used at 2-24 wt%, more preferably 7.5-30 18.5 wt%, more particularly preferably 10-15.75 wt%, based on the total weight of Part A. EXAMPLES Ingredients are listed in Table 1.

⁶ _. ² ⁼ ^y, ₈ ^. ₇ ² = _x _e ^r _u ^t _c u_r ^t S _e ^t _r ^{c g} a ^e ^l _n- _A i_{t r} ^{e r} _eT _A M ^a _{h n} ^t _{s a n}M l^l _{y y} _a ^{r r e} ^c _{u e} _i ^f _o ^t _{c h} ^y ^a _x _e ^g _u ^o _r ^{, -} e_f ^o _n ^{e D p}i y _l ^e ^a _h ^e e ^g _{y g} ^e _h ^D u ^l _o ⁿ _i ^wy ^r _a ^l _h ^t _l ^t e ^y _a ^{l c} _i ^{r o t d} _{y l} ^t _a ^{l T} _{g h} w_{b l} ^t d ^a _{n a} ^{l o t p v} _{a , b} h C_d m_ed ^y _y ^r _x _c ^m _i ^e _y _h ^r _e _c m^e _n ^{h a} _y d _n ^r _c ^a _, C^e _r ^oi_t ^e _y _n ^r _c ^r _e ⁿ _o ^, _o _s ⁵ ₈ ^e _r _s ^e ^t _h m_h _n ^aar ^a t_h ^d ^{t c o} _l ^a _h ^o _t ^a ^s _h ^t _e ^o ^pi_t ^a _h ^g _n ^o ⁱ 4^u _s ^c _n ^a _h ^a ^t _h ^m _{o d} ^l ^e _o ^. ₅ ^u _s e _{e n} ^{i c} _y ^t _{e a} ^l _e ^r _p ^c _n ^t _{e v} ⁶ ^a _. ^a ³ _e ^u _f ⁱ _e ^t ^r _e ^g _i ^l _s ^y ^a _l ^{o 6 a} ^f _e ^e C _{n T} m _Z C m _{E u} ^a _c ^u _f m _{h 5} m _{d u} m _{o b p o} m_i ^d _e ^r _g ^{n r} ₈ ⁰ _{I o n} o _{7 A} ^. _k ^{r i} _{t k} ^M _{1 a} _e ^a _{i A} ⁿ _i ^l _E ^{l m} _be ^v ^d _e ^{H 7} ₆ r^M _{a A} _{b F} ^m M ^{M 9} ^a _{a 1} _T ^r _T ^b _a ^H _{T y} H D C _A N R C 32

₀ ³ ^s _i )^r _n _e ⁱ _{f d} _i ⁿ ^d _a _{o 5} m¹ ^t _c ^e ^a _r _p ^a ^y m ⁱ _l ^d ^l _n _e ^a ^h _s ^x ^- _e ^e ^r _r _o ^e _h

^, _d ⁱ _r _c ^a ₁ ^: e ^c ₂ r _i _u ^o _e ^t ^t _{e a} _c ⁿ ^u _e ^m r ^p _i ^x _o t _o ^r _p ^r ^- _p _{S 2} ^p A cⁱ _t ^a _{h e a A} l^{p n} i_{l a g e} _nM_l ^{- t} _a _a ^{a h} _t ⁿ _i ^{v e} _h ^Dl _s ⁱ ^y _{e b e} ^{t h} _p c _l ^e i ^a _r _n ^u _e ^t _a ^l _a ^h ^hw_{b s d a} ^l _y ^s _o o _{r y} ^r _, ^r ₄ ^. _d ^e _e ^{r e} _t - ^r _c ^h m_e ⁱ _t ^e _{t c e 2 r} ^u _o ^{r a} _l ^{y Al a} _{h p} em^c _n ^s _e ^a _h ^m _o ⁶ _{f s} ^c ^S _{e x o} ^{n t} _{e A} _s ^t _h _n ^e C^a _n ^u _fi ^y _l ^t _e ^{g o a} _{e B} ^b _b ^o _{h e}m ^M D^o _i _p m^l _o T ^g m M^u _r ^t E^h _p ⁱ _{d E} H i d_e ^r _g ^h ^{n r} I_{o n t} . _k ^{o g} _{n e} ₁ ^r _a ⁱ _t _e ^{a 0 e} _r ^t _A ^t ⁶ _a l^m _i _e ^v _{e 7} ⁹ _s ^{r 0} ₃ ^h ⁰ _Ap _b ^{a d} _a ^r _{b 1 a 2 9} ^Ms _o _T ^r _T ^b _a N ^e C _l C⁹ E ^R S_E H^h _p 33

u^t _n ^u ^a _s _{c x} ^o _e ^h ^u _l _r ⁱ ^t _s ^t ^y _l ^m S ^o _o _P ^r _F -^{L )} Y-_{I L} D^{- Y} _Z ⁵ ^l _d ⁱ _c ^c _i _a ^{a r} - H e ^p _-l ^T-⁵ _{, 4}- N_. ⁰ y^% _t c^y _E ³ ( _L Y^E B^t _a ^x _o ^w ⁵ i ^c _i ^l _y ^m _h ^{t M} _I ^S _T ^{Y r} _{d .} ^e ⁰ _ti m ^r _o ^gi _{e e} R_I R^U _XE N ^y _h ^{t n} _o _s ^e _ec ^a _l t _h m^a _h ^o ^t _l ^m ^e _i ^d- ⁿ _i ^T- d⁵ _TB _, -₆ - O TR^{E l} Z_{y a} ^t ^h _{e s} ^a _l _e ^y _n ⁱ _n ^a _l ^N _i _, ^u _l ^{3 ,} ^, ₄ ^, R^D ^E _YN E^% _t _t ^e- ⁿ ⁱ _i ^l ^m _o _n ^e C _n M _V ⁱ _s N^o _{t 1 2 T} H _B w _{d a} W i d - e^{r p}-_{g l} ^y ^{n r} ₀ _{I o n} ⁿ _h ^{t 3} ^. _k ^{r oi} _{t a e 3 0} _{1 a} ^a _i ^l _y ^m _{e x} ⁰ e^{l m} b_e ^v _e ^s _i _a ⁿ ^{8 d} _{- i} ^o ^d _{n A 2} _d a^d _a ^r _b ^A A ⁿ T^r _T ^b _a M _{y 9} ^N _i D⁴ _{6 ,} ^u _l ^a _h ^H N^o _t ^t E_E ^a D _y N 34

-₄ ^. ₂ e² dⁱ _f _x ^o _s ^a ₍ ^t ^{o e} _{g d} ^e _n _{p g} ^k ^{e a} _{t /} ^l _{o r} ^e ^u _l ^a ^{n n} a_em_s ^a _v ⁱ g ^c _r ^m _{e u} ^q ⁿ _i ^{e 0}m _e ^/ ^v _{p 0 s} ^a _g _{a e} ⁵ ^h _{, ( 5} ^. , ^d _i ^{x 5} _{- s 2} A^l _o ^{0 a 5} ₃ _o ^p ₀ n _e ² _P _, _{e n} ^{5 m} _y ^l ^a _f ⁰ _e ^t ^h _{p ,} ^o _{0 a} s _t ⁰ _, _i ⁾ ₂ b^{5 n} _e ⁴ m 1 ⁱ _x ^o ^d ₆ ^t n ¹ ^a _{- n} -^o _{0 r} D_c ⁰ ₀ ^p ^, _p ^a ⁿ _i M_p ^u _{1 f} r_d ^T _o ¹ ^y _{h S} ^r _{g f} ^o ^o _t ^h ^{o A} _g _r ^o _eC ⁱ t ^d _i ^o5 _e o_l ^h _g ^x c^{i n} _{i o} ^{2 wt} p ^{d p} _{t n} e _{r e} ^{a e} _l _n ^y _t ^a f ^o _c ⁱ _{s v} ⁱ ^o _t ^{c a} _, c _a ^{) o} _u ^q u^d _{d 2 c} ^s _e _o ^e _r ⁵ _i ₆ ^v _y 1^{a x} ^r _p ^u _{s -} ^d _o ^p n ^a _e ^D _{n e} oⁱ mM ^a _{, n} _t ^c _{a s} ^T) ^a _S2 ^a ^{5 h}t_{i a} e r ₍ ^A ₆ w ^D ^d _q ^o i ^e _t ¹- ⁰ ₀ u _/ _q ^{i g} _{g n} ⁱ ^{n D} _s ⁰ _, l ² _i ^d ^a ₉ s¹ _r M ^e ^T. _r ² _t i - ^o _{c S)} ^{5 y} _x ^h ^o _g ⁱ ^{t 2} ₈ ^c _a ^A ^o ₄ ⁴ _{- p e} _a ^h _t ¹ _{f d t} ^{e w} n ^e _g ^{Dd r} _a i^o _{t r} ^{u n} _i M_e ^{s l} _u _s ^h _{g s} ^{a d} _r ^T e ^e _r ^{i o} _{S a} ^{b c} _e ^l ^{r y} _{e e} _{u x} ^wm_c ^{c A}-_a ^{o A} _o _l ^m ^{t o t} _{s d t} ^o _{n f} _{c p} ^e _n ^{e a} ( ^e _g u_r ^d _{l r} ⁿ _i ^{e o} ^t _i ^{a %u} ^u _v ⁱ _s ^d _{r h} ^{p G} E _u ⁶ _. ^{a o} _{c s} ⁱ M S_q ⁱ _L ^q _{e b} _e ³ ₂ m^c _{a A} ^T P - - d^{r e} _t m a_{e e} ^{z a u e} i^c _n ⁱ _{n e} _{s t} ^{a t} _a ^r ^{l e d} _{i i} _{a b} ^{x c} _i c _{s a o} ^{r t} _t _s ⁿ _n _e ^o _l _b ^a ^r _c ^e r ^h _g ⁱ _p ^o _{r u} ^a d ^y _e ^p _l ⁱ i ^s _a ^ci ^l _{li e} ^a _l m _{a x n} ⁱ _f ^w _{l d} s^{p p g} _i ^{c e} _{t e} ^{t o} _{p s} ^{e o r} _{a a} ^o _{l n} ⁱ m_{e g s} ^{r d} _l ^{y n} _i ^{p m a} _{ti a} ^{n e} _r ^Gl _uD^y _h ^t _I ^tl _s ^e l_{i e e o} ^t _h m^c _l ^mc _a m ^z _{n e} ^{t n} s_{e u} ^{i p} _i _n ^e _c ^{l c} _o ^d _{i y} _e ^b _r ^{u x} _E _o ^c D M_e ^l ₀ ⁰ _e m H _y ^t i - _u ^b ^e C^a _n ^a _T ⁰ ₁ ^p _s ^u _F ^e B^a _r _p G _a C ^r P^a _q _c ⁱ _L ^p E ^T _{o 0} _P m^, ₂ ^r ₆ _T ^, _{1 i} D _i ^d _e -^r ₂ ⁿ _g ^{1 0} ₈ - _e R ^{n r} ₂ _{I o n} ^{/ 7} C ^e _r C ^. _k ^{r oi} ₄ _t ^B _l C ⁰ i₅ _d ^T A G ^b _{r a 0} 1 ₉ ⁰ _l ₂ ^o _l _{1 a} ^a ₁ ^S- ⁿ _{x n} ^{a k} ₃ ^{7 y} _e _e ^{l m} _i _be ^v N ^{1 9 O} _o ^{b o} _r ^e _g ⁰ _c ^r _n ^{e 3} ₅ ^G ^{a d} _e _a ^r _b ^c _{l 1} ⁰ -^b _a ^{e o} _i ^l ₃ ⁷ _{e 5} ² _u ^{R 2} _{E h} ^t 9 M _e ⁿ _a ^p _{I L} T _T ^r _T ^b _a ^a _{L 0} _T G⁰ _{3 a} ^rt C_{l p} U ^u _L ⁰ _{5 e} H₈ ^b D_{u 3} ^k H Q_a H _E D ^Z X ^{T m} _i _P ^r _o _T ^r _p D H _B D 3

_e ^r _u ^t _c u_r ^t S - -_y ^x ^l _o ^l a ^r _d c^y _y _{i h} ^h _t e d ^{e t} _a ^l m_e ^e _y _{t e} ^x _y _o ^r ^r _c _s ^{e a} ^t _h m^a _l ^{y n} t_e _n ^{au u} _d _l ^y _h o _h ^t ^- _e ^e C _{n B t 2} m _i ^d _e ^r _g ^{n r} _{I o n} ^. _k ₁ ^{r o} a ⁱ _t _e ^a ^{l m} _i _be ^v _e ^r _A ^{a d} _{a T} ^M _T ^r _b _T ^b _a ^H B_E H 36 Preparation of toughener 1 The toughener was made using the ingredients listed in Table 2. Table 2. Ingredients in toughener 1 Ingredient Wt% 1 PTMEG 75.82 2 Trimethylol propane 0.52 3 1,6-HDI 13.66 4 DBTL 0.05 5 BHT 0.01 6 HEMA 9.94 Ingredients 1 and 2 (PTMEG and trimethylol propane) were added to a reactor and heated to 120^oC under vacuum while stirring. Stirring was continued for 30 minutes. The reactor was allowed to cool to 60^oC and ingredient 3 (1,6-HDI) was added. Mixing was continued for two minutes. Ingredient 4 (DBTL) was added and mixing was continued for 40 minutes. The NCO content was determined by FTIR to be 3.5 wt%. Ingredient 5 (BHT) was added and mixing was continued for 20 minutes, and the mixture was cooled to 50^oC. Ingredient 6 (HEMA) was added and the mixture was mixed for 40 minutes. The NCO content was determined by FTIR to be approximately 0. The number average molecular weight (M_n) was determined by GPC to be 6,119 Da and the weight average molecular weight (M_w) was determined to be 15,084 Da. The GPC method used was as follows: An aliquot (0.4991 g) of the toughener was weighed into a 16-mL screw capped glass vial equipped with a Teflon-lined screw cap using an analytical balance (Sartorius, model 1702). Ten mL of tetrahydrofuran (THF, Baker Analyzed, HPLC solvent, low water) was transferred into the glass vial using a 10-mL transfer pipette. The content was mixed thoroughly using a vortex mixer (Scientific Industries, Inc., Vortex Genie 2, model G-560). About 1.5 mL of the solution was then transferred into an autosampler vial for GPC analysis. Molecular Weight Calibration Standards: Calibration Standard 1: The following narrow molecular weight distribution polymer standards were weighed into a 25 mL screw capped glass vial equipped with a Teflon-lined screw cap using an analytical balance: Polystyrene, Mp = 139,400 (0.0522 g); Polystyrene, Mp = 32,300 (0.0628 g); Polyethylene Glycol, Mp = 3,140 (0.0735 g); Polyethylene Glycol, Mp = 600 (0.0853 g); Polyethylene Glycol, M_p = 180 (0.1038 g). Twenty five mL of THF was added into the glass vial using a 25-mL transfer pipette. The solution was mixed thoroughly with a vortex mixer. About 1.5 mL of the solution was then transferred into an autosampler vial for GPC analysis. Calibration Standard 2: The following narrow molecular weight distribution polymer standards were weighed into a 25 mL screw capped glass vial equipped with a Teflon-lined screw cap using an analytical balance: Polystyrene, Mp = 568,700 (0.0506 g); Polystyrene, Mp = 61,600 (0.0608 g); Polyethylene Glycol, M_p = 7,750 (0.0757 g); Polyethylene Glycol, M_p = 970 (0.0828 g); Polyethylene Glycol, M_p = 400 (0.1019 g). Twenty five mL of THF was added into the glass vial using a 25-mL transfer pipette. The solution was mixed thoroughly with a vortex mixer. About 1.5 mL of the solution was then transferred into an autosampler vial for GPC analysis. GPC Analysis: Solutions of the test substance and molecular weight calibration standards were analyzed using the following conditions: Chromatograph: Waters 2695 equipped with a Waters column heater module. Column: Four 7.8 mm ID X 300 mm Styragel columns: HR1 + HR2 + HR3 + HR4 (Waters), connected in series Temperature: 35^oC Mobile Phase: THF (Baker Analyzed, HPLC solvent, low water), 1 mL/min, isocratic Injection Volume: 25 μL Run Time: 50 min Detector: Waters 410 Differential Refractive Index Detector Sample Rate: 1 Temperature: 35^oC Filter Time: 1 Sensitivity: 4 Polarity: +ve Waters Empower Software, Build 2154, was used for data acquisition and data processing. Ultraviolet Curing of Urethane Acrylates Cured samples of urethane acrylates were prepared by blending the urethane acrylate with 10 wt% of a photoinitiator, ESACURE KTO 46 (IGM Resins), and speedmixing for 2 minutes at 2000 rpm. The urethane acrylate/photoinitator blends were heated in an oven to 55 °C to reduce the viscosity to allow them to be poured into a 2 mm deep HDPE mold. The molded resins were then cured by passing the samples on a conveyor system under ultraviolet light generated under the following conditions: UV Source: Innovative Machines Mercury 200 W/in, 10 ft/min, 4 A, 1200 V Sample Distance from light – 50 mm Conveyor Speed – 10 ft/min. Irradiance according to EIT Power Puck II S/N 11178: Peak Intensity (mJ/cm2) Total Power (mW/cm2) UVA 698.5 812.2 UVB 684.0 793.2 UVC 114.3 134.4 UVD 477.7 560.3 ________________________________________ Dynamic Mechanical Analysis (DMA) The UV-cured urethane acrylate castings were cut to dimensions of 30 mm x 7 mm x 2 mm (± 0.5 mm) bars. Data was collected on a TA Instruments Q800 DMA in tension film mode from –90 °C to 100 °C with a 3 °C/min ramp rate and 1 Hz frequency. Tanδ as a function of temperature was plotted and the glass transition temperature was measured at the maximum tanδ value. Preparation of adhesive All formulations were mixed using a dual asymmetric centrifugal FlackTek SpeedMixer^® DAC 400 FVZ by Hauschild Engineering using the following procedure. Inventive and comparative samples were prepared using the ingredients listed in Tables 3 and 4. Table 3. Composition of Part A of inventive and comparative samples Inventive Comparative Comparative Example 1 Example 2 Example 3 Part A Part A Part A Ingredient Wt% Wt% Wt% THFMA 31.45 31.45 31.45 Dymalink 708 (zinc dimethacrylate) 1.00 1.00 1.00 CHMA (cyclohexyl methacrylate) 4.00 4.00 4.00 Toughener 1 20.00 -- -- CN1967 (difunctional aliphatic urethane -- 20.00 -- methacrylate oligomer toughener based on polyester polyols) CN1970 (difunctional aliphatic polyester -- -- 20.00 urethane methacrylate oligomer) Clearstrength E920 (MBS core-shell 13.00 13.00 13.00 rubber) SR9036A (ethoxylated bis-A- 6.00 6.00 6.00 dimethacrylate) HEMA phosphate 4.70 4.70 4.70 Methacrylic acid 3.00 3.00 3.00 Dynasilan 6498 (vinyl oligomeric siloxane) 0.50 0.50 0.50 N,N-dimethyl-p-toluidine 0.75 0.75 0.75 Ethanox 330 [1, 3, 5-TRIMETHYL-2,4,6- 0.60 0.60 0.60 TRIS (3,5-DI-TERT-BUTYL-4- HYDROXYBENZYL) BENZENE] pre-blend in THFMA DEHA (diethylhydroxylamine) pre-blend in 0.60 0.60 0.60 THFMA Wollastonite (Nyad 200) 10.00 10.00 10.00 Talc 1N 0.50 0.50 0.50 10 mil glass beads 0.90 0.90 0.90 Cab-O-Sil Ultrabond 5780 (fumed silica) 3.00 3.00 3.00 Table 4. Composition of Part B of inventive and comparative samples B Side Ingredient Wt% Luperox ATC50 (benzoyl peroxide paste in 7.30 plasticizer) Cab-O-Sil Ultrabond 5780 (fumed silica) 0.50 Heliogen Green (dye) 0.10 Hubercarb (CaCO₃) 39.10 Hakuenka CCR (precipitated calcium carbonate) 18.00 DER 331 (epoxy resin) 21.00 XZ92579 (epoxy resin) 6.00 1% BHT in DER 331 pre-blend 8.00 Part A procedure 1. The THFMA was added to a reactor with the Clearstrength core shell rubber and the Dymalink and the mixture was mixed and then speed mixed for 3 minutes at 2,100 rpm. 2. The remaining THFMA was added and mixed and then speed mixed for 2 minutes at 2,100 rpm. The CHMA was added as well as half the Cab-O-Sil. The mixture was mixed for 1 minute at 2,100 rpm. 3. Half of Toughener 1 or urethane methacrylates (CN1967 / CN1970) was added. The mixture was mixed for 2 minutes at 2,100 rpm. The sides were scraped down. The remaining Toughener 1 or urethane methacrylates was added and mixed for 2 minutes at 2100 rpm 4. Add Wollastonite and Talc fillers and mix for mix for 2 minutes at 2100 rpm. 5. The SR9036A was added and mixing was continued for 2 minutes at 2,100 rpm. 6. The HEMA phosphate, Dynasylan 6498, and methacrylic acid were added and mixing was continued for 2 minutes at 2,100 rpm. 7. The N,N-dimethyl toluidine and glass beads were added and mixing was continued for 25 seconds at 800 rpm followed by 1 minute at 2,000 rpm. The sides of the vessel were scraped down and the mix cycle was repeated. 8. The mixture was mixed at 30 mbar vacuum and 1,800 rpm for 3 minutes. Part B procedure 1. The stabilizer pre-blend (1 wt% BHT in DER 331) was made: epoxy resin and BHT were added to a reaction vessel. The mixture was heated to 90^oC and held for 1 hour to dissolve the BHT. The vessel was allowed to cool to 70^oC then speed mixed for 2 minutes at 2,100 rpm. 2. The stabilizer pre-blend (1 wt% BHT in DER 331), epoxy resin and fillers were added and the mixture was mixed for 2 minutes at 2,100 rpm. 3. The sides were scraped down and then mixing was continued for 2 minutes at 2,100 rpm. The mixture was allowed to cool to room temp. 4. The peroxide was added and mixing was continued for 25 seconds at 800 rpm and 1 minute at 2,000 rpm. The sides were scraped down and the mixing cycle was repeated. The mixture was mixed at 30 mbar vacuum and 1,800 rpm for 3 minutes. Impact Peel Testing Impact testing was performed with an Instron CEAST Crush Tower, according to ISO 11343. Specimens were prepared using electrogalvanized steel, cleaned with acetone and then oiled at 3g/m² with Oest Platinol B 804/3 COW-1 metal forming lubricant. Part A and Part B of the adhesive were mixed in a 3:1 weight ratio, and mixed by hand in a bag for 1 minute. The bond area was 20 X 30 mm, with a 10 mil bond gap. The bonded specimens were cured for 1 day at 23^oC, followed by 45 minutes at 190^oC. The high-temperature phase was designed to simulate e-coating conditions, to which such adhesives would likely be exposed. The specimens were bolted to the load cell and a moving wedge was inserted as described in ISO11343 test method. The crosshead with a 50lb weight attached was dropped from a fixed height at a velocity of 6.7 ft/s. The cleavage force was measured and converted to N/mm of bond line. The results are listed in Table 5. Table 5. Impact peel strength for inventive and comparative samples [Part A:Part B = 3:1 by weight], 20 mm X 30 mm bond area, 10 mil bond gap, ISO 11343 method Part A Substrate Cure Test Failure Average temperature mode impact peel (N/mm) over 3 samples Inventive CF¹ Example 1 CF 27.9 CF Comparative Oiled 1 day @ BRIT² Example 2 electrogalvanized 23^oC + 45“ 23^oC BRIT 0.1 steel @ 190^oC BRIT Comparative BRIT Example 3 BRIT 1.0 BRIT 1. CF = cohesive failure 2. BRIT = brittle failure It is clear from the results that Comparative samples using a conventional toughener (e.g. CN1967 and CN1970) show unacceptably low impact peel strength and brittle failure, making them unsuitable for use. The Inventive sample shows excellent impact peel strength and exclusively cohesive failure. Also noteworthy is the fact that the Inventive sample shows excellent impact peel strength even after the high-temperature exposure used to simulate e- coat curing conditions. Acrylic adhesives typically cannot withstand such conditions. Lap Shear testing Lap Shear specimens were prepared and tested according to the ISO Standard ISO 4587. The substrate used was 0.8 mm thick electro-galvanized steel supplied by ACT Laboratories, Inc. Test coupons were cut into 1 X 4 in. strips. The ½ inch bonding overlap section of each coupon was cleaned with acetone and then oiled at a weight of 3 g/m² with Oest Platinol B 804/3 COW- 1 metal forming lubricant. The two components of the adhesive were combined in a 3:1 [Part A: Part B] ratio by weight and mixed by hand in a bag for 1 minute. The adhesive was applied to the bonding section of the coupon. Another coupon was laid on top, and the specimen was assembled in a fixture yielding a ½ inch overlap. The edges of the assembly were scraped clean using a spatula and held together with binder clips while curing at room temperature for 24 hours followed by a 45-minute oven bake at 190°C (metal temperature). The high-temperature phase was designed to simulate e- coating conditions, to which such adhesives would likely be exposed. The loads to failure of the Lap Shears were measured using an Instron^® 5500R Materials Testing System (Instron Corporation) at room temperature. Mechanical grips were used to hold the Lap Shear samples in place. The distance between the grips was seven inches. The crosshead speed was 0.5 in./min. The computer measured the load as a function of crosshead displacement and loads were converted to pounds of force per square inch of bond area. After each Lap Shear was tested to failure, a failure mode was assigned by visual evaluation. Failure modes were classified as either adhesive failure or cohesive failure and a percentage was assigned. The results are listed in Table 6.

Table 6. Lap shear strength for inventive and comparative samples [Part A:Part B = 3:1 by weight], 0.5 in/min., 0.5 in. overlap, 10 mil bond gap, ISO 4587 Part A Substrate Cure Test Failure mode Average max. temperature stress (MPa) over 3 samples Inventive CF Example 1 CF 13.3 CF Comparative 1 day @ CF ¹ ACT EG w/ 23^oC R /TFCF Example 2 T + oil 45“ @ 23^oC CF/TFCF 15.0 190^oC CF/TFCF Comparative CF/TFCF Example 3 CF/TFCF 15.7 CF/TFCF 1. TFCF = Thin Film Cohesive Failure. Adhesive still remains on both sides of the substrate but the adhesive layer after failure is much thinner on one side of the substrate versus the other. The results in Table 6 show that the Inventive sample shows good lap shear strength and is comparable to the Comparative samples. Together with the results in Table 5, these results show that the Inventive sample achieves excellent impact peel strength and good lap shear strength. This combination of characteristics is not easy to achieve with acrylic adhesives when they are subjected to e-coating conditions (high-temperatures of > 180^oC). E-coating is carried out in the final stages of automobile manufacture, making it essential that adhesives be able to maintain their impact peel strength and lap shear strength after exposure to e-coating conditions.

Claims

Claims 1. A two-component epoxy-acrylic hybrid adhesive, comprising: Part A ai) at least one methacrylate monomer; aii) at least one methacrylate-terminated toughener having a T_g of 0^oC or less; aiii) a phosphorus-containing compound selected from mono- esters of phosphonic, mono- and di-esters of phosphonic and phosphoric acids having one unit of vinyl or allylic unsaturation present; aiv) a tertiary amine radical initiator; Part B bi) at least one epoxy resin; bii) an oxidizing agent.

2. A method for adhering two or more substrates, comprising the steps: (1) providing a two-component epoxy hybrid adhesive, comprising Part A ai) at least one methacrylate monomer; aii) at least one methacrylate-terminated toughener having a Tg of 0^oC or less; aiii) a phosphorus-containing compound selected from mono- esters of phosphonic, mono- and di-esters of phosphonic and phosphoric acids having one unit of vinyl or allylic unsaturation present; aiv) a tertiary amine radical initiator; Part B bi) at least one epoxy resin; bii) an oxidizing agent; (2) mixing Part A and Part B to obtain an adhesive mixture; (3) applying the adhesive mixture to a first substrate, a second substrate or both; (4) bringing the first substrate and the second substrate into adhesive contact; and (5) allowing the adhesive mixture to cure.

3. Claim 1 or 2, wherein the at least one toughener has a Tg of -20^oC or less, when measured by DMA.

4. Claim 1, 2 or 3, wherein the toughener has a Tg of -40^oC or less, when measured by DMA.

5. Any one preceding claim, wherein the at least one toughener comprises or consists of a toughener prepared from a polyetherpolyol reacted with a polyisocyanate, followed by end-capping with a hydroxyalkyl ester of methacrylic acid.

6. Any one preceding claim, wherein the at least one methacrylate monomer (ai) comprises a molecule of the general structure of Formula I:

where R is an organic radical.

7. Any one preceding claim, wherein Part A additionally comprises one or more divalent metal salts of methacrylic acid, preferably zinc dimeythacrylate.

8. Claim 6, wherein R is selected from H, a C₁-C₁₈ substituted or unsubstituted cyclic or noncyclic aliphatic hydrocarbon radical, which may contain one or more heteroatoms, and a C4-C18 aromatic hydrocarbon radical, which may contain one or more heteroatoms.

9. Claim 6, wherein R is selected from a C1-C18 substituted or unsubstituted, cyclic or noncyclic aliphatic hydrocarbon radical, which may contain one or more heteroatoms, in particular R is cyclohexyl or CH2-THF, where THF is a 2- or 3-tetrahydrofurfuryl radical.

10. Any one preceding claim, wherein Part A comprises two or more methacrylate monomers.

11. Any one preceding claim, wherein the at least one methacrylate monomer comprises tetrahydrofurfuryl methacrylate.

12. Any one preceding claim, wherein the at least one methacrylate monomer comprises cyclohexyl methacrylate.

13. Any one preceding claim, wherein Part A additionally comprises a divalent metal salt of methacrylic acid, in particular zinc dimethacrylate.

14. Any one preceding claim, wherein the at least one methacrylate monomer comprises tetrahydrofurfuryl methacrylate and cyclohexyl methacrylate.

15. Any one preceding claim, wherein the at least one methacrylate monomer comprises tetrahydrofurfuryl methacrylate and cyclohexyl methacrylate.

16. Any one preceding claim, wherein the methacrylate monomer or monomers represents 25-35 wt%, more preferably 28-32 wt% tetrahydrofurfuryl methacrylate, based on the total weight of Part A.

17. Any one preceding claim, wherein Part A comprises 25-35 wt%, more preferably 28-32 wt% tetrahydrofurfuryl methacrylate, based on the total weight of Part A.

18. Any one preceding claim, wherein Part A comprises 2-10 wt%, more preferably 3-6 wt% cyclohexyl methacrylate, based on the total weight of Part A.

19. Any one preceding claim, wherein Part A comprises 0.5-4 wt%, more preferably 0.75-1.5 wt% of a divalent metal salt of methacrylic acid, based on the total weight of Part A.

20. Any one preceding claim, wherein Part A comprises 0.5-4 wt%, more preferably 0.75-1.5 wt% of zinc dimethacrylate, based on the total weight of Part A.

21. Any one preceding claim, wherein Part A comprises 25-35 wt%, more preferably 28-32 wt% tetrahydrofurfuryl methacrylate, and 2-10 wt%, more preferably 3-6 wt% cyclohexyl methacrylate, based on the total weight of Part A.

22. Any one preceding claim, wherein Part A comprises 25-35 wt%, more preferably 28-32 wt% tetrahydrofurfuryl methacrylate, 2-10 wt%, more preferably 3-6 wt% cyclohexyl methacrylate, and 0.5-4 wt%, more preferably 0.75-1.5 wt% of zinc dimethacrylate, based on the total weight of Part A.

23. Any one preceding claim, wherein the polyether polyol used to make the toughener is a diol or triol.

24. Any one preceding claim, wherein the polyether polyol used to make the toughener is a diol.

25. Any one preceding claim, wherein the polyether polyol used to make the toughener is a poly(C2-C6-alkylene oxide) diol, with C2, C3 and C4 being preferred, and C4 being particularly preferred [i.e. poly(tetramethylene oxide)glycol or PTMEG].

26. Any one preceding claim, wherein the polyether polyol used to make the toughener is selected from PTMEG’s having molecular weights from 1,000 to 3,000 Da, more preferably 2,000 Da.

27. Any one preceding claim, wherein the polyisocyanate used to make the toughener is aliphatic or aromatic.

28. Any one preceding claim, wherein the polyisocyanate used to make the toughener is aliphatic.

29. Any one preceding claim, wherein the polyisocyanate used to make the toughener is a diisocyanate.

30. Any one preceding claim, wherein the polyisocyanate used to make the toughener is selected from hexamethylene diisocyanate (HDI), isophorone diisocyanate, and methylene dicyclohexyl diisocyanate.

31. Any one preceding claim, wherein the polyether polyol used to make the toughener is PTMEG and the polyisocyanate is HDI.

32. Any one preceding claim, wherein the hydroxyalkyl ester of methacrylic acid used to make the toughener is a C2-C6-hydroxyalkyl ester.

33. Any one preceding claim, wherein the hydroxyalkyl ester of methacrylic acid used to make the toughener is a C2-C4-hydroxyalkyl ester.

34. Any one preceding claim, wherein the hydroxyalkyl ester of methacrylic acid used to make the toughener is a C2-C3-hydroxyalkyl ester.

35. Any one preceding claim, wherein the hydroxyalkyl ester of methacrylic acid used to make the toughener is hydroxyethyl methacrylate, HEMA):

.

36. Any one preceding claim, wherein the toughener is of the general Formula II: where x has a value between 13 and 42.

37. Claim 36, wherein x is 27.8.

38. Claim 36 or 37, wherein y has values of 1.5 to 5.

39. Any one of claims 36 to 38, wherein y has values of 1.8 to 4.9.

40. Any one of claims 36 to 39, wherein y is 2.6.

41. Any one preceding claim, wherein the toughener is of general Formula II, and has a number average molecular weight (M_n) of 6,119 Da, as determined by gel permeation chromatography (GPC), according to the method recited in the Examples section.

42. Any one preceding claim, wherein the toughener is of general Formula II, and has a weight average molecular weight (M_w) of 15,084 Da, as determined by gel permeation chromatography (GPC), according to the method recited in the Examples section.

43. Any one preceding claim, wherein Part A comprises 10-30 wt% toughener (aii), based on the total weight of Part A.

44. Any one preceding claim, wherein Part A comprises 15-25 wt% toughener (aii), based on the total weight of Part A.

45. Any one preceding claim, wherein Part A comprises 17-22 wt% of toughener (aii), based on the total weight of Part A.

46. Any one preceding claim, wherein the phosphorus-containing compound (aiii) is is of the Formulae III, IV and V: where W is the same or different, and each W is independently selected from H, and a divalent organic radical, with at least one W being a divalent organic radical, and at least one X is a vinyl group, and the other(s) is(are) a vinyl group or absent (in case W is H), or H.

47. Any one preceding claim, wherein the phosphorus-containing compound (aiii) is of Formula V.

48. Any one preceding claim, wherein the phosphorus-containing compound (aiii) is of Formula V and one, two or three X groups are vinyl.

49. Any one preceding claim, wherein the phosphorus-containing compound (aiii) is of Formula V and one X group is vinyl.

50. Any one preceding claim, wherein the phosphorus-containing compound (aiii) is of Formula V and one, two or three WX groups are of the Formula VI:

where the dot represents the point of radical attachment.

51. Claim 50, wherein one or two WX groups are of Formula VI, and the remaining WX group(s) is(are) H.

52. Any one preceding claim, wherein the phosphorus-containing compound comprises a molecule of Formula VII:

.

53. Any one preceding claim, wherein the phosphorus-containing compound comprises a molecule of Formula VIII: .

54. Any one preceding claim, wherein the phosphorus-containing compound (aiii) is an approximate 2:1 mixture of Formula VII and Formula VIII.

55. Any one preceding claim, wherein the tertiary amine radical initiator is N,N-dimethyl-p-toluidine.

56. Any one preceding claim, wherein the at least one epoxy resin comprises a diglycidyl ether of a polyhydric phenol compound.

57. Any one preceding claim, wherein the at least one epoxy resin comprises a reaction product of bisphenol A and epichlorohydrin.

58. Any one preceding claim, wherein the at least one epoxy resin comprises a liquid reaction product of bisphenol A and epichlorohydrin.

59. Any one preceding claim, wherein the at least one epoxy resin comprises a liquid reaction product of epichlorohydrin and bisphenol A, having an epoxide equivalent weight of 182-192 g/eq (as measured according to ASTM D-1652), an epoxide percentage of 22.4-23.6 % (as measured according to ASTM D-1652), an epoxide group content of 5,200-5,500 mmol/kg (as measured according to ASTM D-1652), and a viscosity at 25^oC of 11,000-14,000 mPas (as measured according to ASTM D-445).

60. Any one preceding claim, wherein the at least one epoxy resin comprises a bisphenol A-based epoxy resin with an epoxy equivalent weight of approximately 352.5 g/equivalent.

61. Any one preceding claim, wherein the at least one epoxy resin comprises a mixture of a liquid reaction product of epichlorohydrin and bisphenol A, having an epoxide equivalent weight of 182-192 g/eq (as measured according to ASTM D-1652), an epoxide percentage of 22.4- 23.6 % (as measured according to ASTM D-1652), an epoxide group content of 5,200-5,500 mmol/kg (as measured according to ASTM D- 1652), and a viscosity at 25^oC of 11,000-14,000 mPas (as measured according to ASTM D-445), and a bisphenol A-based epoxy resin with an epoxy equivalent weight of approximately 352.5 g/equivalent.

62. Any one preceding claim, wherein the at least one epoxy resin comprises 50-90 wt%, more preferably 60-80 wt% of a liquid reaction product of epichlorohydrin and bisphenol A, having an epoxide equivalent weight of 182-192 g/eq (as measured according to ASTM D- 1652), an epoxide percentage of 22.4-23.6 % (as measured according to ASTM D-1652), an epoxide group content of 5,200-5,500 mmol/kg (as measured according to ASTM D-1652), and a viscosity at 25^oC of 11,000-14,000 mPas (as measured according to ASTM D-445), based on the total weight of epoxy resin in Part B.

63. Any one preceding claim, wherein the at least one epoxy resin comprises 10-50 wt%, more preferably 20-40 wt% of a bisphenol A- based epoxy resin with an epoxy equivalent weight of approximately 352.5 g/equivalent, based on the total weight of epoxy resin in Part B.

64. Any one preceding claim, wherein the at least one epoxy resin comprises 50-90 wt%, more preferably 60-80 wt% of a liquid reaction product of epichlorohydrin and bisphenol A, having an epoxide equivalent weight of 182-192 g/eq (as measured according to ASTM D- 1652), an epoxide percentage of 22.4-23.6 % (as measured according to ASTM D-1652), an epoxide group content of 5,200-5,500 mmol/kg (as measured according to ASTM D-1652), and a viscosity at 25^oC of 11,000-14,000 mPas (as measured according to ASTM D-445), and 10- 50 wt%, more preferably 20-40 wt% of a bisphenol A-based epoxy resin with an epoxy equivalent weight of approximately 352.5 g/equivalent, based on the total weight of epoxy resin in Part B.

65. Any one preceding claim, wherein Part B comprises the at least one epoxy resin at from 20 to 80 wt%, more preferably 20 to 60 wt%, more particularly preferably 25 to 40 wt% of epoxy resin, based on the total weight of Part B.

66. Any one preceding claim, wherein the oxidizing agent is an organic peroxide.

67. Any one preceding claim, wherein the oxidizing agent is selected from benzoyl peroxide and other diacyl peroxides, hydroperoxides such as cumene hydroperoxide, peresters such as β-butylperoxybenzoate; ketone hydroperoxides such as methyl ethyl ketone hydroperoxide, organic salts of transition metals such as cobalt naphthenate, and compounds containing a labile chlorine such as sulfonyl chloride.

68. Any one preceding claim, wherein the organic peroxide is benzoyl peroxide.

69. Any one preceding claim, wherein the organic peroxide is present in Part B at 3-10 wt%, more preferably 5-9 wt%, based on the total weight of Part B.

70. Any one preceding claim, wherein Part B comprises benzoyl peroxide at 3-10 wt%, more preferably 5-9 wt%, based on the total weight of Part B.

71. Any one preceding claim, wherein Part A and/or Part B comprises stabilizers and/or radical stabilizers.

72. Any one preceding claim, wherein Part A and/or Part B comprises a stabilizer and/or radical scavenger selected from 1, 3, 5-TRIMETHYL- 2,4,6-TRIS (3,5-DI-TERT-BUTYL-4-HYDROXYBENZYL) BENZENE, di- ethylhydroxy amine (DEHA), butylated hydroxy toluene (BHT), and mixtures of these.

73. Any one preceding claim, wherein Part A and/or Part(B) comprises a filler selected from wollastonite, talc, fumed silica, calcium carbonate and mixtures of these.

74. Any one preceding claim, wherein Part A comprises an additional toughener.

75. Any one preceding claim, wherein Part A comprises an additional toughener that is rubber based, such as acrylate-based tougheners, butadiene-based tougheners, acrylonitrile-butadiene-based tougheners, chlorinated or chlorosulphonated polyethylenes, block copolymers of styrene and conjugated dienes (SBS, SIS), ethylene acrylic elastomers, core-shell graft copolymers.

76. Any one preceding claim, wherein Part A additionally comprises a rubber-based toughener.

77. Any one preceding claim, wherein part A additionally comprises a rubber-based toughener selected from acrylate-based tougheners, butadiene-based tougheners, acrylonitrile-butadiene-based tougheners, chlorinated or chlorosulphonated polyethylenes, block copolymers of styrene and conjugated dienes (SBS, SIS), ethylene acrylic elastomers, core-shell graft copolymers. 77. Any one preceding claim, wherein Part A additionally comprises a rubber-based toughener that is a copolymer of 2-propeneoic acid, 2- methyl-, methyl ester with 1,3-butadiene.

78. Any one preceding claim, wherein the additional rubber-based toughener is used in Part A at 2-24 wt%, more preferably 7.5-18.5 wt%, more particularly preferably 10-15.75 wt%, based on the total weight of Part A.

79. Any one preceding claim, wherein Part A additionally comprises a rubber-based toughener, used at 2-24 wt%, more preferably 7.5-18.5 wt%, more particularly preferably 10-15.75 wt%, based on the total weight of Part A.

80. Any one preceding claim, wherein part A additionally comprises a rubber-based toughener selected from acrylate-based tougheners, butadiene-based tougheners, acrylonitrile-butadiene-based tougheners, chlorinated or chlorosulphonated polyethylenes, block copolymers of styrene and conjugated dienes (SBS, SIS), ethylene acrylic elastomers, core-shell graft copolymers, used at 2-24 wt%, more preferably 7.5-18.5 wt%, more particularly preferably 10-15.75 wt%, based on the total weight of Part A 81. Any one preceding claim, wherein Part A comprises a rubber-based toughener that is a copolymer of 2-propeneoic acid, 2-methyl-, methyl ester with 1,3-butadiene, used at 2-24 wt%, more preferably 7.5-18.5 wt%, more particularly preferably 10-15.75 wt%, based on the total weight of Part A.