TWO COMPONENT (2K) CURABLE ADHESIVE COMPOSITION

Abstract

The present invention is directed to a curable and debondable two-part (2K) adhesive composition comprising: i) a first part comprising: (meth)acrylate monomer; co-polymerizable acid; and, an electrolyte; and, ii) a second part comprising: a first curing agent for the monomers of said first part; a second curing agent for the monomers of said first part; and, a solubilizer.

Claims

1. A curable and debondable two-part adhesive composition comprising: a first part comprising (meth)acrylate monomer; co-polymerizable acid; and an electrolyte; and a second part comprising a first curing agent for the (meth)acrylate monomers of said first part; a second curing agent for the (meth)acrylate monomer of said first part; and a solubilizer.

2. A curable and debondable two-part adhesive composition according to claim 1, wherein said (meth)acrylate monomer is selected from the group consisting of methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl(meth)acrylate, isobutyl (meth)acrylate, Cert-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, cyclohexyl (meth)acrylate, n-heptyl (meth)acrylate, n-octyl(meth)acrylate, 2-ethylhexyl-(meth)acrylate, nonyl (meth) acrylate, decyl (meth)acrylate, dodecyl (meth)acrylate, phenyl (meth)acrylate, tolyl (meth)acrylate, benzyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, 3-methoxybutyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl(meth)acrylate, stearyl(meth)acrylate, glycidyl (meth)acrylate, isobornyl (meth)acrylate, 2-aminoethyl (meth)acrylate, y-(meth)acryloyloxypropyl trimethoxysilane, (meth)acrylic acid-ethylene oxide adduct, trifluoromethylmethyl (meth)acrylate, 2-trifluoromethylethyl (meth)acrylate, 2-perfluoro ethylethyl (meth)acrylate, 2-perfluoroethyl-2-perfluorobutylethyl (meth)acrylate, 2-perfluoroethyl (meth)acrylate, perfluoromethyl (meth)acrylate, diperfluoromethylmethyl (meth)acrylate, 2-perfluoromethyl-2-perfluoroethylmethyl (meth)acrylate, 2-perfluorohexylethyl (meth)acrylate, 2-perfluorodecylethyl (meth)acrylate, 2-perfluorohexadecylethyl (meth)acrylate, ethoxylated trimethylolpropane triacrylate, trimethylol propane trimethacrylate, dipentaerythritol monohydroxypentacrylate, pentaerythritol triacrylate, ethoxylated trimethylolpropane triacrylate, 1,6-hexanedioldiacrylate, neopentyl glycoldiacrylate, pentaerythritol tetraacrylate, 1,2-butylene glycoldiacrylate, trimethylopropane ethoxylate tri(meth)acrylate, glyceryl propoxylate tri(meth) acrylate, trimethylolpropane tri(meth)acrylate, dipentaerythritol monohydroxy penta(meth)acrylate, tripropylene glycol di(meth)acrylate, neopentylglycol propoxylate di(meth)acrylate, 1,4-butanediol di(meth)acrylate, polyethyleneglycol di(meth)acrylate, triethyleneglycol di(meth)acrylate, butylene glycol di(meth)acrylate, ethoxylated bisphenol A di(meth)acrylate and mixtures thereof, preferably said (meth)acrylate monomer is selected from the group consisting of methyl methacrylate, methyl acrylate, ethyl methacrylate, ethyl acrylate, isobornyl methacrylate, isobornyl acrylate, ethoxylatedtrimethylolpropanetriacrylate, trimethylolpropane triacrylate and mixtures thereof.

3. A curable and debondable two-part adhesive composition according to claim 1, wherein said (meth)acrylate monomer component is present in an amount of from 20 to 80% by weight of the total weight of the first part.

4. A curable and debondable two-part adhesive composition according to claim 1, wherein said co-polymerizable acid is selected from the group consisting of methacrylic acid, acrylic acid, itaconic acid, maleic acid, aconitic acid, crotonic acid, fumaric acid and mixtures thereof.

5. A curable and debondable two-part adhesive composition according to claim 1, wherein said copolymerisable acid is present in an amount of from 0.25 to 20% by weight of the total weight of the first part.

6. A curable and debondable two-part adhesive composition according to claim 1, wherein said electrolyte is selected from the group consisting of 1-ethyl-3-methylimidazolium methansulfonate, 1-ethyl-3-methylimidazolium methyl sulfate, 1-hexyl-3-methylimidazolium 2-(2-fluoroanilino)-pyridinate, 1-hexyl-3-methylimidazolium imide, 1-butyl-1-methyl-pyrrolidinium 2-(2-fluoroanilino)-pyridinate, 1-butyl-1-methyl-pyrrolidinium imide, trihexyl (tetradecyl) phospholium 2-(2-fluoroanilino)-pyridinate, cyclohexyltrimethylammonium bis (trifluormethylsulfonyl) imide, di (2-hydroxyethyl) ammonium trifluoroaetate, N,N-dimethyl (2-hydroxyethyl) ammonium octanoate, methyltrioctylammonium bis (trifluoromethylsulfonyl) imide, N-ethyl-N—N—N—N-tetramethylguanidinium trifluorometanesulfonate, guanidinium trifluoromethanesulfonate, 1-butyl-4-methylpyridinium bromide, 1-buthyl-3-methylpyridinium tetrafluoroborate, 1-butyl-3-hydroxymethylpyridinium ethylsulfate, 1-butyl-1-methylpyrrolidinium bis (trifluoromethylsulfonyl) imide, 1-butyl-methylpyrrolidinium tris (pentafluoroethyl) trifluorophosphate, 3-methyl imidazolium ethylsulfate, 1-ethyl-3-methylimidazolium chloride, 1-ethyl-3-ethyl-methylimidazolium bromide, 1-butyl-3-methylimidazolium chloride, 1-hexyl-3-methylimidazolium chloride, 1-octyl-3-methylimidazolium chloride, 1-methyl-3-octylimidazolium chloride, 1-propyl-3-methylimidazolium iodide, 1-butyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium trifluoromethanesulfonate, 1-butyl-3-methylimidazolium hexafluorophosphate, 1-butyl-2,3-dimethylimidazolium tetrafluoroborate, 1-butyl-2,3-dimethylimidazolium hexafluorophosphate, 1-butylimidazol, 1-methylimidazolium tetrafluoroborate, tetrabutylphosphonium tris(pentafluoroethyl) trifluorophosphate, trihexyl (tetradecyl) phosphonium tetrafluoroborate and mixtures thereof, preferably selected from 1-ethyl-3-methylimidazolium methansulfonate, 1-ethyl-3-methylimidazolium methyl sulfate, and mixtures thereof.

7. A curable and debondable two-part adhesive composition according to claim 1, wherein said electrolyte is present in an amount of from 2.5 to 25% by weight of the total weight of the first part.

8. A curable and debondable two-part adhesive composition according to claim 1, wherein said first curing agent is a peroxide curing agent, said peroxide curing agent selected from the group consisting of tert-butyl peroxide, tert-butyl perbenzoate, cumene hydroperoxide, tert-butyl peroxybenzoate, diacetyl peroxide, benzoyl peroxide, tert-butyl peracetate, lauryl peroxide and mixtures thereof.

9. A curable and debondable two-part adhesive composition according to claim 1, wherein said first curing agent is present in an amount of from 25 to 75% by weight of the total weight of the second part.

10. A curable and debondable two-part adhesive composition according to claim 1, wherein said second curing agent is a metal compound selected from salts and complexes of iron, copper, cobalt, vanadium and manganese.

11. A curable and debondable two-part adhesive composition according to claim 1, wherein said second curing agent is present in an amount of from 0.01 to 5% by weight of the total weight of the second part.

12. A curable and depondable two-part adhesive composition according to claim 1, wherein said solubilizer is polyethylene glycol or epoxy resin selected from the group consisting of cycloaliphatic epoxides, epoxy novolac resins, bisphenol-A-epoxy resins, bisphenol-F-epoxy resins, bisphenol-A epichlorohydrin based epoxy resins, alkyl epoxides, limonene dioxides, polyepoxides and mixtures thereof.

13. A curable and debondable two-part adhesive composition according to claim 1, wherein said solubilizer is present in an amount of from 20 to 45% by weight of the total weight of the second part.

14. A curable and debondable two-part adhesive composition according to claim 1, wherein said first part and/or said second part further comprise electrically conductive particles selected from the group consisting of carbon black, silver and mixtures thereof.

15. A bonded structure comprising: a first material layer having an electrically conductive surface; and, a second material layer having an electrically conductive surface; wherein the cured debondable two-part adhesive composition according to claim 1 is disposed between the first and second material layers.

16. A method of debonding said bonded structure according to claim 15, the method comprising the steps of: i) applying a voltage across both surfaces to form an anodic interface and a cathodic interface; and, ii) debonding the surfaces.

17. A method according to the claim 16, wherein the voltage applied in step i) is from 0.5 to 100 V.

Description

[0210] The present invention will be described with reference to the appended drawings in which:

[0211] FIG. 1a illustrates a bonded structure in accordance with a first embodiment of the present invention.

[0212] FIG. 1b illustrates a bonded structure in accordance with a second embodiment of the present invention.

[0213] FIG. 2a illustrates the initial debonding of the structure of the first embodiment upon passage of a current across that structure.

[0214] FIG. 2b illustrates the initial debonding of the structure of the second embodiment upon passage of a current across that structure.

[0215] FIGS. 3a and 3b illustrate the results of lap shear strength testing of stainless steel substrates bonded with a cured adhesive composition in accordance with an embodiment of the present invention.

[0216] FIGS. 4a and 4b illustrate the results of lap shear strength testing of aluminium substrates bonded with a cured adhesive composition in accordance with an embodiment of the present invention.

[0217] FIGS. 5a and 5b illustrate the stability over time results.

[0218] FIG. 6 a illustrates bar chart of a storage period and subsequent to the application of a constant potential of 75V across the adhesive layer for a duration of 20 minutes, as captured in Table 14.

[0219] FIG. 7 illustrates a bar chart of a storage period and subsequent to the application of a constant potential of 75V across the adhesive layer for a duration of 20 minutes, as captured in Table 17.

[0220] FIG. 8 illustrates a bar chart of a storage period and subsequent to the application of a constant potential of 30V across the adhesive layer for a duration of 20 minutes, as captured in Table 21.

[0221] FIG. 9 illustrates a bar chart of a storage period and subsequent to the application of a constant potential of 75 V 20 minutes, as captured in Table 24.

[0222] As shown in FIG. 1a appended hereto, a bonded structure is provided in which a layer of cured adhesive (10) is disposed between two conductive substrates (11). A layer of non-conductive material (12) may be disposed on the conductive substrates (11) to form the more complex bonded structure as depicted in FIG. 1b. Each layer of conductive substrate (11) is in electrical contact with an electrical power source (13) which may be a battery or an AC-driven source of direct current (DC). The positive and negative terminals of that power source (13) are shown in one fixed position but the skilled artisan will of course recognize that the polarity of the system can be reversed.

[0223] The two conductive substrates (11) are shown in the form of a layer which may be constituted by inter alia: a metallic film; a metallic sheet; a metallic mesh or grid; deposited metal particles; a resinous material which is rendered conductive by virtue of conductive elements disposed therein; or, a conducting oxide layer. As exemplary conductive elements there may be mentioned silver filaments, single-walled carbon nanotubes and multi-walled carbon nanotubes. As exemplary conducting oxides there may be mentioned: doped indium oxides, such as indium tin oxide (ITO); doped zinc oxide; antimony tin oxide; cadmium stannate; and, zinc stannate. The selection of the conductive material aside, the skilled artisan will recognize that the efficacy of the debonding operation may be diminished where the conductive substrates (11) are in the form of a grid or mesh which offers limited contact with the layer of cured adhesive (10).

[0224] When an electrical voltage is applied between each conductive substrate (11), current is supplied to the adhesive composition (10) disposed there between. This induces electrochemical reactions at the interface of the substrates (11) and the adhesive composition, which electrochemical reactions are understood as oxidative at the positively charged or anodic interface and reductive at the negatively charged or cathodic interface. The reactions are considered to weaken the adhesive bond between the substrates allowing the easy removal of the debondable composition from the substrate.

[0225] As depicted in FIGS. 2a and 2b, the debonding occurs at the positive interface, that interface between the adhesive composition (10) and the electrically conductive surface (11) that is in electrical contact with the positive electrode. By reversing current direction prior to separation of the substrates, the adhesive bond may be weakened at both substrate interfaces.

[0226] It is however noted that the composition of the adhesive layer (10) may be moderated so that debonding occurs at either the positive or negative interface or simultaneously from both. For some embodiments a voltage applied across both surfaces so as to form an anodic interface and a cathodic interface will cause debonding to occur simultaneously at both the anodic and cathodic adhesive/substrate interfaces. In an alternative embodiment, reversed polarity may be used to simultaneously disbond both substrate/adhesive interfaces if the composition does not respond at both interfaces to direct current. The current can be applied with any suitable waveform, provided that sufficient total time at each polarity is allowed for debonding to occur. Sinusoidal, rectangular and triangular waveforms might be appropriate in this regard and may be applied from a controlled voltage or a controlled current source.

[0227] Without intention to limit the present invention, it is considered that the debonding operation may be performed effectively where at least one and preferably both of the following conditions are instigated: a) an applied voltage of from 0.5 to 100 V; and, b) the voltage being applied for a duration of from 1 second to 60 minutes. Where the release of the conductive substrate from the cured adhesive is to be facilitated by the application of a force—exerted via a weight or a spring, for instance—the potential might only need to be applied for the order of seconds. In some embodiments potential of 5V for a duration of 10 minutes is sufficient to have a debonding effect, whereas in some embodiments, potential of 3.5V for a duration of 30 minutes is sufficient.

[0228] It is desired that after the debonding, the adhesive composition is solely on a first substrate or a second substrate, meaning that one of the substrates is substantially free of adhesive.

[0229] The following examples are illustrative of the present invention and are not intended to limit the scope of the invention in any way.

EXAMPLES

[0230] The following materials were employed in the Examples: [0231] Aerosil 200: Hydrophilic fumed silica, available from Evonik Industries. [0232] Clearstrength® XT100: Core-shell toughening agent (methylmethacrylate-butadiene-styrene, MBS) available from Arkema Inc. [0233] 1-Ethyl-3-methylimidazolium methansulfonate: Available from TCI America Inc. [0234] Ferrocene: bis(η5-cyclopentadienyl)iron, available from Sigma Aldrich. [0235] DER 331: Bisphenol-A epoxy resin, available from Dow Chemical. [0236] Benzoyl peroxide (75%): Powder, available from Arkema Inc.

Example 1

[0237] Parts (A) and (B) of a composition 1 were prepared in accordance with Table 1 herein below.

TABLE-US-00001 TABLE 1 Part A Weight % by weight Component [g] of stated part Methylmethacrylate 5.50  54.98% Methacrylic acid 1.20  11.96% 1-Ethyl-3-methylimidazolium 1.70  17.00% methane sulfonate Clearstrength XT 100 1.42  14.17% Aerosil 200 0.19  1.89% Total 10.0 100.00% Part B Weight % by weight Part B [g] of stated part Ferrocene 0.02  0.17% D.E.R. 331 3.61  36.36% Benzoyl peroxide 6.31  63.47% Total 10 100%  

[0238] The parts (A, B) were loaded in an equal amount by weight into separate compartments of a 50 g cartridge and sealed at both ends. The cartridge was then loaded into a cartridge-gun and a mixing tip was installed on the front end. By application of constant pressure on the trigger, the two parts were pushed into the mixing tip to ensure sufficient mixing before application to the stated substrate.

[0239] The substrates were copper (thickness 1 mm), aluminium (AA6016, thickness 1.25 mm) and stainless steel (1.4301, thickness 1.5 mm) each with a thickness of Substrates were cut into 2.5 cm×10 cm (1″×4″) in size for tensile testing.

[0240] Tensile lap shear (TLS) test was performed according to test method described on page 5.

[0241] The applied two-part (2K) adhesive compositions were cured in the overlapping region by the application of a temperature of 100° C. for 30 minutes. Subsequently, the samples were stored at 25° C. with 20% humidity in a climate chamber.

[0242] For each substrate, tensile lap shear strength was investigated both after said storage period and subsequent to the application of a constant potential of 75V across the adhesive layer for a duration of 1 hour. The results are documented in Table 2 herein below.

TABLE-US-00002 TABLE 2 Initial Bond Bond Strength after 75 Substrate Strength (MPa) V, 1 hour (MPa) Copper  2.5 (±0.13) 0.95 (±0.21) Aluminium 15.99 (±1.16) 2.08 (±0.63) Stainless Steel 17.31 (±3.31) 0.06 (±0.03)

[0243] For the adhesively bonded stainless steel substrate, lap shear strength (MPa) was investigated under two conditions: a) over a period of 20 minutes applying a constant potential (75 V) across the overlapping bonded area; and, b) applying different potentials across the overlapping bonded region for a fixed period of time (10 minutes). The results of these investigations are given in FIGS. 3a and 3b appended hereto.

[0244] For the adhesively bonded aluminium substrate, lap shear strength (MPa) was investigated under two conditions: a) over a period of 20 minutes applying a constant potential (75 V) across the overlapping bonded area; and, b) applying different potentials across the overlapping bonded region for a fixed period of time (10 minutes). The results of these investigations are given in FIGS. 4a and 4b appended hereto.

Example 2

[0245] Parts (A) and (B) of a composition 2 were prepared in accordance with Table 3 herein below. Composition 2 was prepared and tested according to the methods described in example 1.

TABLE-US-00003 TABLE 3 Part A Weight % by weight Component [g] of stated part Methylmethacrylate 5.50  54.98% Methacrylic acid 1.20  11.96% 1-Ethyl-3-methylimidazolium 1.70  17.00% methyl sulphate Clearstrength XT 100 1.42  14.17% Aerosil 200 0.19  1.89% Total 10.0 100.00% Part B Weight % by weight Part B [g] of stated part Ferrocene 0.02  0.17% D.E.R. 331 3.61  36.36% Benzoyl peroxide 6.31  63.47% Total 10 100%  

[0246] For each substrate, tensile lap shear strength was investigated both after said storage period and subsequent to the application of a constant potential of 75V across the adhesive layer for a duration of 1 hour. The results are documented in Table 4 herein below.

TABLE-US-00004 TABLE 4 Initial Bond Bond Strength after Substrate Strength (MPa) 75 V, 1 hour (MPa) Aluminium 13.96 (±0.65) 2.26 (±0.42) Stainless Steel 20.81 (±0.65) 0.54 (±0.1) 

Example 3

[0247] Parts (A) and (B) of a composition 3 were prepared in accordance with Table 5 herein below. Composition 3 was prepared and tested according to the methods described in example 1.

TABLE-US-00005 TABLE 5 Part A Weight % by weight Component [g] of stated part Methylmethacrylate 5.63  56.32% Methacrylic acid 1.22  12.20% 1-Ethyl-3-methylimidazolium 1.00  10.00% methane sulfonate Clearstrength XT 100 1.46  14.56% Aerosil 200 0.19  1.92% Silver SF7-AT 0.50  5.00% Total 10.0 100.00% Part B Weight % by weight Part B [g] of stated part Ferrocene 0.02  0.17% D.E.R. 331 3.61  36.36% Benzoyl peroxide 6.31  63.47% Total 10 100%  

[0248] For a substrate, tensile lap shear strength was investigated both after said storage period and subsequent to the application of a constant potential of 75V across the adhesive layer for a duration of 1 hour. The results are documented in Table 6 herein below.

TABLE-US-00006 TABLE 6 Initial Bond Bond Strength after Substrate Strength (MPa) 75 V, 1 hour (MPa) Aluminium 11.94 (±0.5) 5.94(±)

Example 4

[0249] Parts (A) and (B) of a composition 4 were prepared in accordance with Table 7 herein below. Composition 4 was prepared and tested according to the methods described in example 1.

TABLE-US-00007 TABLE 7 Part A Weight % by weight Component [g] of stated part Methylmethacrylate 5.50 54.98 Methacrylic acid 1.20 11.96 1-Ethyl-3-methylimidazolium methane sulfonate 1.70 17.00 Clearstrength XT 100 1.42 14.17 Aerosil 200 0.19 1.89 Total 10.0 100.00 Part B Weight % by weight Part B [g] of stated part saccharin 3.64 1.41 Cumene hydroperoxide 6.35 83.55 Benzoyl peroxide 0.02 0.20 Hydrin C200XL 1.50 15.00 Total 10 100%

[0250] For each substrate, tensile lap shear strength was investigated both after said storage period and subsequent to the application of a constant potential of 75V across the adhesive layer for a duration of 1 hour. The results are documented in Table 8 herein below.

TABLE-US-00008 TABLE 8 Initial Bond Bond Strength after 75 V, Substrate Strength (MPa) 1 hour (MPa) Aluminium 4.47 (±1.09) 0.044(±)

Example 5

[0251] Parts (A) and (B) of a composition 5 were prepared in accordance with Table 9 herein below. Composition 5 was prepared and tested according to the methods described in example 1.

TABLE-US-00009 TABLE 9 Part A Weight % by weight Component [g] of stated part Methylmethacrylate 5.50  54.98% Methacrylic acid 1.20  11.96% 1-Ethyl-3-methylimidazolium methane sulfonate 1.70  17.00% Clearstrength XT 100 1.42  14.17% Aerosil 200 0.19  1.89% Total 10.0 100.00% Part B Weight % by weight Part B [g] of stated part Copper(H)acetylacetonate 0.09  0.17% D.E.R. 331 3.61  36.36% Benzoyl peroxide 6.31  63.47% Total 10 100%  

[0252] For each substrate, tensile lap shear strength was investigated both after said storage period and subsequent to the application of a constant potential of 75V across the adhesive layer for a duration of 1 hour. The results are documented in Table 10 herein below.

TABLE-US-00010 TABLE 10 Initial Bond Strength Bond Strength after 75 V, Substrate (MPa) 1 hour (MPa) Aluminium 14.58 (±0.59) 3.86 (±0.63)

[0253] In view of the foregoing description and examples, it will be apparent to those skilled in the art that equivalent modifications thereof can be made without departing from the scope of the claims.

Example 6

[0254] Stability test was conducted for the composition of example 1. For this test, normal lap shear samples were prepared and cured at 100° C. for 30 min. Aluminium and steel substrates were used. Subsequently, the samples were stored at 25° C. with 20% humidity in a climate chamber. The lap shear was measured after one day, seven days, 14 days, 28 days, 60 days and 90 days. The results are documented in Table 11 and Table 12 herein below.

TABLE-US-00011 TABLE 11 Initial Bond Strength Bond Strength after 75 V, Aluminium (MPa) 1 hour (MPa) 1 day 13.87 +/− 1.49  2.1 +/− 0.78  7 days 14.26 +/− 0.35   2 +/− 0.37 14 days  15.5 +/− 1.16 2.74 +/− 1.05 28 days 15.99 +/− 1.16 2.44 +/− 0.96 60 days 15.69 +/− 0.9  1.93 +/− 0.93

TABLE-US-00012 TABLE 12 Stainless Initial Bond Strength Bond Strength after 75 V, steel (MPa) 1 hour (MPa) 1 day 15.74 +/− 1.27 0.2  7 days 13.34 +/− 3.31  0.1 +/− 0.11 14 days 14.42 +/− 2.77  0.08 +/− 0.11 28 days 18.39 +/− 2.71 0.046 +/− 0.07 60 days 12.76 +/− 0.74  0.08 +/− 0.01 90 days 17.61 +/− 3.39 0

[0255] The stability results are illustrated in FIGS. 5a and 5b. FIG. 5a illustrates adhesion properties and debonding effect on aluminium, while FIG. 5b illustrates the same on stainless steel. The test results show that the composition according to the present invention has good initial adhesion properties and does not lose them over the time. In addition, the composition according to the present invention has good initial debonding effect and maintains it over the time.

Example 7

[0256] Parts (A) and (B) of a composition 6a and 6b were prepared in accordance with Table 13 herein below. Compositions 6a abd 6b were prepared and tested according to the methods described in example 1.

TABLE-US-00013 TABLE 13 Composition 6a Part A Weight % by weight Component [g] of stated part Composition 6a Methylmethacrylate 5.63 54.98% 6.01 60.69 Methacrylic acid 1.22 11.96% 1.32 13.20 1-Ethyl-3- 1.00 17%   2.1 20.9 methylimidazolium methanebsulfonate Clearstrength XT 100 1.46 14.17% 0.00 Cab-O-Sil TS 720 0.19  1.89% 0.52 5.23 Total 10.0 100.00%  10 100 Composition 6a Part B Weight % by weight Composition 6b Part B [g] of stated part Part B Ferrocene 0.02  0.17% 0.02  0.17% D.E.R. 331 3.61 36.36% 3.61 36.36% Benzoyl peroxide 6.31 63.47% 6.31 63.47% Total 10 100%    10 100%   

[0257] For a substrate, tensile lap shear strength was investigated both after said storage period and subsequent to the application of a constant potential of 75V across the adhesive layer for a duration of 20 minutes. The results are documented in Table 14 herein below. The test results are illustrated in FIG. 6.

TABLE-US-00014 TABLE 14 Substrate Initial Bond Strength Bond Strength after 75 AA6016 (MPa) V, 20 minutes (MPa) Composition 6a 18.19 (±1.3) 5.19 (±1.9) Composition 6b 10.38 (±2.2) 0.64 (±)  

Example 8

[0258] Composition 7 was prepared in accordance with Table 15 herein below. It is noted that methacrylic acid was left out from the composition, otherwise the composition is according to the present invention.

TABLE-US-00015 TABLE 15 Part A Weight % by weight Component [g] of stated part Methylmethacrylate 6.69 66.94% Methacrylic acid 0.00 1-Ethyl-3-methylimidazolium 1.70 17.00% methane sulfonate Clearstrength XT 100 1.42 14.17% Aerosil 200 0.19  1.89% Total 10.0 100.00%  Part B Weight % by weight Part B [g] of stated part Ferrocene 0.09  0.17% D.E.R. 331 3.61 36.36% Benzoyl peroxide 6.31 63.47% Total 10 100%   

[0259] Composition 7 does not cure, and the electrolyte separates from the composition.

Example 9

[0260] Compositions 8a, 8b and 8c were prepared in accordance with Table 16 herein below.

TABLE-US-00016 TABLE 16 Composition Composition Composition 8a 8b 8c % by % by % by weight weight weight Weight of stated Weight of stated Weight of stated [g] part [g] part [g] part Part A Part A Part A Methylmethacrylate 5.89 58.88% 5.63 56.32% 5.91 59.12% Methacrylic acid 1.28 12.81% 1.22 12.20% 1.29 12.86% 1-Ethyl-3-methylimidazolium 1.00 10.00% 1.00 10.00% 1.08 10.75% methane sulfonate Clearstrength XT 100 1.52 15.17% 1.46 14.56% 1.52 15.24% Aerosil 200 0.20  2.02% 0.19  1.92% 0.2  2.03% Silver SF7-AT 0.11  1.12% 0.50  5.00% — 0 10.0   100% 10.0   100% 100% Part B Part B Part B Ferrocen 0.02  0.17% 0.02  0.17% 0.02  0.17% D.E.R331 3.64 36.36% 3.64 36.36% 3.64 36.36% Benzylperoxide 6.35 63.47% 6.35 63.47% 6.35 63.47% Total 10.0   100% 10.0   100% 10.0   100%

[0261] For a substrate, tensile lap shear strength was investigated both after said storage period and subsequent to the application of a constant potential of 75V across the adhesive layer for a duration of 20 minutes. The results are documented in Table 17 herein below and in addition the test results are illustrated in FIG. 7.

TABLE-US-00017 TABLE 17 Substrate Initial Bond strength after AA6016 bond strength 75 V 20 minutes Composition 8a 15.19 (±0.86) 10.69 (±0.74) Composition 8b 11.94 (±0.5)   5.93 (±2.27) Composition 8c 16.92 (±0.46) 15.44 (±0.28)

Example 10

[0262] Compositions 9a, 9b and 9c were prepared in accordance with Table 18 herein below.

TABLE-US-00018 TABLE 18 Composition 9a Composition 9b Composition 9c % by % by % by weight of weight of weight of According to Weight stated Weight stated Weight stated Composition [g] part [g] part [g] part 8c Part A Part A Part A Methylmethacrylate 5.89 58.88% 5.63 56.32% 5.91 59.12% 5.91 59.12 Methacrylic acid 1.28 12.81% 1.22 12.20% 1.29 12.86% 1.29 12.86 1-Ethyl-3- 1.00 10.00% 1.00 10.00% 1.08 10.00% 1.08 10.75 methylimidazolium methane sulfonate Clearstrength XT 1.52 15.17% 1.46 14.56% 1.52 15.24% 1.52 1.52 100 Aerosil 200 0.20  2.02% 0.19  1.92% 0.2  2.03% 0.2 2.03 Printex L (Carbon 0.11  1.12% Black) Kappa 20 PWD — 0.11 1.12 (Carbon Black) Y200 (Carbon — — 0.11 1.12 Black) Garamite (rheology 0.33 3.3 0.33 3.3 0.3 3.3 additive) Part B Part B Part B Ferrocen 0.02  0.17% 0.02  0.17% 0.02  0.17% D.E.R331 3.64 36.36% 3.64 36.36% 3.64 36.36% Benzylperoxide 6.35 63.47% 6.35 63.47% 6.35 63.47% Total 10.0   100% 10.0   100% 10.0   100%

[0263] For a substrate, tensile lap shear strength was investigated both after said storage period and subsequent to the application of a constant potential of 75V across the adhesive layer for a duration of 20 minutes. The results are documented in Table 19 herein below.

TABLE-US-00019 TABLE 19 Substrate Initial Bond Bond Strength after 75 AA6016 Strength (MPa) V, 20 minutes (MPa) Composition 9a  7.59 (±1.48)  3.6 (±1.33) Composition 9b 10.16 (±1.11)  4.73 (±2.06) Composition 9c 11.82 (±0.29)  4.55 (±1.55) Composition 8c 16.92 (±0.46) 15.44 (±0.28)

Example 11

[0264] Different electrolyte concentrations were tested. Compositions 10a, 10b, 10c, 10d and 10e were prepared in accordance with Tables 20A and 20B herein below.

TABLE-US-00020 TABLE 20A Composition 10a Composition 10b % by % by weight weight of Composition 10c Weight of stated Weight stated Weight % by weight [g] part [g] part [g] of stated part Part A Part A Part A Methylmethacrylate 8.63 43.14 8.42 42.14 8.23 41.14 Methacrylic acid 1.96 9.81 1.96 9.81 1.96 9.81 1-Ethyl-3-methylimidazolium 2.4 12 2.6 13 2.8 14 methane sulfonate Clearstrength XT 100 2.6 13.01 2.6 13.01 2.6 13.01 Aerosil 200 0.344 1.72 0.344 1.72 0.344 1.72 PEG 400 0.36 1.83 0.36 1.83 0.36 1.83 Zeoforte ZSC2195LCX 0.8 4.00 0.8 4.00 0.8 4.00 Kraton D1155 0.8 4.00 0.8 4.00 0.8 4.00 Blendex 338 0.8 4.00 0.8 4.00 0.8 4.00 Crayvallac SLT 0.8 4.00 0.8 4.00 0.8 4.00 Harcyl 1228 (phosphoric acid 0.2 1.00 0.2 1.00 0.2 1.00 2-hydroxyethyl methacrylate ester) 2,2’-(4-methylphenylimino) 0.3 1.5 0.3 1.5 0.3 1.5 diethanol 20.0   100% 20.0   100% 20   100% Part B Part B Part B Ferrocen 0.017  0,17% 0.017  0,17% 0.017  0,17% D.E.R. 331 3.626 36,26% 3.626 36,26% 3.626 36,26% Benzoylperoxid 5.34 53,37% 5.34 53,37% 5.34 53,37% GPX 801 0.02  0,20% 0.02  0,20% 0.02  0,20% Polyester 1.0 10,00% 1.0 10,00% 1.0 10,00% Total 10.0   100% 10.0   100% 10.0   100%

TABLE-US-00021 TABLE 20B Composition 10d Composition 10e Part A Part A % by % by Weight weight of Weight weight of [g] stated part [g] stated part Methylmethacrylate 8.13 40.64 8.03 40.14 Methacrylic acid 1.96 9.81 1.96 9.81 1-Ethyl-3- 2.9 14.5 3.0 15 methylimidazolium methane sulfonate Clearstrength XT 100 2.6 13.01 2.6 13.01 Aerosil 200 0.344 1.72 0.344 1.72 PEG 400 0.36 1.83 0.36 1.83 Zeoforte ZSC2195LCX 0.8 4.00 0.8 4.00 Kraton D1155 0.8 4.00 0.8 4.00 Blendex 338 0.8 4.00 0.8 4.00 Crayvallac SLT 0.8 4.00 0.8 4.00 Harcyl 1228 (phosphoric 0.2 1.00 0.2 1.00 acid 2-hydroxyethyl methacrylate ester) 2,2′-(4-methyl- 0.3 1.5 0.3 1.5 phenylimino) diethanol 20 100% 20 100% Part B Part B % by % by Weight weight of Weight weight of [g] stated part [g] stated part Ferrocen 0.017  0.17% 0.017  0.17% D.E.R. 331 3.626 36.26% 3.626 36.26% Benzoylperoxid 5.34 53.37% 5.34 53.37% GPX 801 0.02  0.20% 0.02  0.20% Polyester 1.0 10.00% 1.0 10.00% Total 10.0 100%   10.0 100%  

[0265] For a substrate, tensile lap shear strength was investigated both after said storage period and subsequent to the application of a constant potential of 30V across the adhesive layer for a duration of 20 minutes. The results are documented in Table 21 herein below. The test results are illustrated in FIG. 8.

TABLE-US-00022 TABLE 21 Substrate Initial bond Bond strength after AA6016 strength 75 V 20 minutes Composition 10a 17.41_(±1.04)  7.66 (±3.29) Composition 10b 16.09 (±1.17) 4.13 (±0.22) Composition 10c 16.28 (±1.37) 1.84 (±0.84) Composition 10d 13.03 (±0.93) 1.43 (±0.34) Composition 10e 12.12 (±2.24) 0.98 (±0.37)

Example 12

[0266] Different toughener and core shell particles concentrations showing improvement of T-Peel and impact to aging test (90% Rh), stability and LSS values. Compositions 11a, 11b, 11c, 11d and 11e were prepared in accordance with Table 22 herein below.

TABLE-US-00023 TABLE 22 Composition Composition Composition Composition Composition 11a 11b 11c 11d 11e % by % by % by % by % by weight weight weight weight weight of of of of of Weight stated Weight stated Weight stated Weight stated Weight stated [g] part [g] part [g] part [g] part [g] part Part A Part A Part A Part A Part A Methylmethacrylate 5.05 50.47 .05 50.47 4.78 47.82 4.65 46.49 4.2 42.03 Methacrylic 1.96 10.97 1.09 10.97 1.04 10.39 1.01 10.11 0.91 9.14 acid 1-Ethyl-3- 2.4 10 1.0 10 1.0 10 1.0 10 1.0 10 methylimidazolium methane sulfonate Clearstrength 2.6 13.01 1.3 13.01 1.23 12.33 1.2 11.98 1.0 10 XT 100 Aerosil 200 0.344 1.72 0.17 1.72 0.16 1.63 0.16 1.58 0.15 1.5 PEG 400 0.36 1.83 0.18 1.83 0.18 1.83 0.18 1.83 0.18 1.83 3 3 Kraton D1155 0 0 0.4 4.00 0.6 6.00 1 10.00 1 10.00 Blendex 338 0 0 0.4 4.00 0.6 6.00 0.4 4.00 1 10.00 Crayvallac 0.8 4.00 0.4 4.00 0.4 4.00 0.4 4.00 0.4 4.00 SLT 10.0   100% 10.0   100% 10   100% 10   100% 10   100% Part B Part B Part B Part B Part B Ferrocen 0.02  0.17% 0.02  0.17% 0.02  0.17% 0.02  0.17% 0.02  0.17% D.E.R. 331 3.64 36.36% 3.64 36.36% 3.64 36.36% 3.64 36.36% 3.64 36.36% Benzoylperoxid 6.35 63.47% 6.35 63.47% 6.35 63.47% 6.35 63.47% 6.35 63.47% Total 10.0   100% 10.0   100% 10.0   100% 10.0   100% 10.0   100%

[0267] For a substrate, tensile lap shear strength was investigated both after said storage period and subsequent to the application of a constant potential of 30V across the adhesive layer for a duration of 20 minutes. The results are documented in Table 23 herein below.

TABLE-US-00024 TABLE 23 Substrate Initial bond Bond strength after AA6016 strength 75 V 20 minutes Composition 11a 10.54 (±1.5)  0.54 (± 0.24) Composition 11b 15.28 (±0.86) 5.38 (±0.51) Composition 11c 15.33 (±1.37) 2.34 (±0.3)  Composition 11d   14 (±0.35) 5.12 Composition 11e 16.55 (±0.07) 5.5 (±0.4)

[0268] Table 24 below shows Lap shear Strength (LSS) test results, which are also illustrated in FIG. 9.

TABLE-US-00025 TABLE 24 Substrate Wedge impact test Peel Strength AA6016 (ISO 11343) (STM 710) Composition 11a 1.15 (±1.31) 0 Composition 11b 12.8 (±2.8)  2.38 Composition 11c 1.63 (±0.99) 2.39 Composition 11d 1.05 (±0.06) 3.45 Composition 11e 9.46 (±0.84) 2.44