ONE COMPONENT (1K) CURABLE ADHESIVE COMPOSITION

Abstract

The present invention is directed to a curable and one component (1K) debondable adhesive composition comprising: a) epoxy resin; b) a curing agent for said epoxy resin; c) an electrolyte; and, d) an electrically non-conductive filler; wherein said composition comprises at least one of: e) a combination of a solubilizer and a toughener; and, f) electrically conductive particles.

Claims

1. A curable and one component (1K) debondable adhesive composition comprising: a) epoxy resin; b) a curing agent for said epoxy resin; c) an electrolyte; and, d) an electrically non-conductive filler; wherein said composition comprises at least one of: e) a combination of a solubilizer and a toughener; and, f) electrically conductive particles.

2. A curable and debondable adhesive composition according to claim 1, wherein said epoxy resin is selected from the group consisting of bis-phenol A epoxy resin, bis-phenol F epoxy resin, mixture of bis-phenol A epoxy resin and bis-phenol F epoxy resin and mixtures thereof.

3. A curable and debondable adhesive composition according to claim 1, wherein said epoxy resin is present in an amount of from 15 to 75% by weight of the total weight of the composition.

4. A curable and debondable adhesive composition according to claim 1, wherein said curing agent comprises of a thiol-based curing agent selected from the group consisting of tris-(3-mercaptopropionate) (TMP), pentaerythritoltetra(3-mercaptopropionate), di-pentaerythritolhexa(3-mercaptopropionate), pentaerythritoltetra(3-mercaptopropionate), tris(2-(mercaptopropionyloxy)ethyl)isocyanate and mixtures thereof.

5. A curable and debondable adhesive composition according to claim 1, wherein said curing agent comprises of an amine-based curing agent, selected from the group consisting of cycloaliphatic amines, aliphatic amines, dicyanodiamides, polyether amines and mixtures thereof, wherein said amine-based curing agent is selected from polyether amines, dicyanodiamides, and mixtures thereof.

6. A curable and debondable adhesive composition according to claim 1, wherein said curing agent is present in an amount of from 0.01 to 25% by weight of the total weight of the composition.

7. A curable and debondable 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 trifluoromethanesulfonate, guanidinium trifluoromethanesulfonate, 1-butyl-4-methylpyridinium bromide, 1-butyl-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, wherein said electrolyte is selected from 1-ethyl-3-methylimidazolium methansulfonate, 1-ethyl-3-methylimidazolium methyl sulfate and mixtures thereof.

8. A curable and debondable adhesive composition according to claim 1, wherein said electrolyte is present in an amount of from 2.0 to 25% by weight of the total weight of the composition.

9. A curable and debondable adhesive composition according to claim 1, wherein said electrically non-conductive filler is selected from the group consisting of calcium carbonate, calcium oxide, talcum, fumed silica, silica, wollastonite, barium sulphate and mixtures thereof.

10. A curable and debondable adhesive composition according to claim 1, wherein said electrically non-conductive filler is present in an amount of from 1 to 50% by weight of the total weight of the composition.

11. A curable and debondable adhesive composition according to claim 1, wherein said solubilizer is selected from: polyoxyalkylene glycols; silicone surfactants; polpolyhydric alcohols; and, sugars.

12. A curable and debondable adhesive composition according to claim 1, wherein said solubilizer is present in an amount of from 1 to 15% by weight of the total weight of the composition.

13. A curable and debondable adhesive composition according to claim 1 wherein toughener is present in an amount of from 5 to 40% by weight of the total weight of the composition.

14. A curable and debondable adhesive composition according to claim 1 comprising electrically conductive particles selected from the group consisting of silver, carbon black and mixtures thereof.

15. A curable and debondable adhesive composition according to claim 1, wherein said electrically conductive particles are present in an amount of from 0.1 to 5% by weight of the total weight of the composition.

16. A bonded structure comprising a first material layer having an electrically conductive surface; and, a second material layer having an electrically conductive surface; wherein curable and debondable adhesive composition according to claim 1 is disposed between the first and second material layers.

17. A method of debonding said bonded structure according to claim 16, the method comprising the steps of: 1) applying a voltage across both surfaces to form an anodic interface and a cathodic interface; and 2) debonding the surfaces.

18. A method according to the claim 17, wherein the voltage applied in step 1 is from 0.5 to 200 V.

Description

[0202] The present invention will be described with reference to the appended drawings in which:

[0203] FIG. 1a illustrates a bonded structure in accordance with a first embodiment of the present invention.

[0204] FIG. 1b illustrates a bonded structure in accordance with a second embodiment of the present invention.

[0205] FIG. 2a illustrates the initial debonding of the structure of the first embodiment upon passage of a current across that structure.

[0206] FIG. 2b illustrates the initial debonding of the structure of the second embodiment upon passage of a current across that structure.

[0207] FIG. 3a illustrates the debonding effect with 75 V over time.

[0208] FIG. 3b illustrates the debonding with different potentials applied for 30 min.

[0209] FIGS. 4, 5 and 6 illustrate stability of the compositions according to the present invention over time.

[0210] FIG. 7 illustrates a bar chart of relative strength over time at a temperature of 140° C. of Example 5a and 5d, as captured in Table 14.

[0211] FIG. 8 illustrates a bar chart of relative strength over time at a temperature of 100° C. of Example 5d, as captured in Table 15.

[0212] FIG. 9 illustrates a bar chart of relative strength over time at a temperature of 140° C. of Example 6a and 6b, as captured in Table 17, and of Example 6c.

[0213] 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.

[0214] 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).

[0215] 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.

[0216] 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.

[0217] 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. 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 200 V; and, b) the voltage being applied for a duration of from 1 second to 120 minutes, for example from 1 second to 60 minutes or from 1 second to 30 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.

[0218] The following examples are illustrative of the present invention and are not intended to limit the scope of the invention in any way.

EXAMPLES

[0219] The following materials were employed in the Examples: [0220] DER 331: Liquid Epoxy Resin, reaction product of epichlorohydrin and bisphenol A, available from Olin. [0221] DER 337: Intermediate epoxy equivalent weight semi-solid resin based on Bisphenol-A epoxy, available from Olin. [0222] DER 337-X80: Intermediate epoxy equivalent weight semi-solid resin based on Bisphenol-A epoxy in xylene, available from Olin. [0223] TMP: Trimethylolpropane tris (3mercaptopropionate) from sigma aldrich [0224] Dyhard 100SH: Dicyandiamide, available from AlzChem Group AG. 1-methylimidazole: Available from BASF. [0225] Ajicure PN—H: Epoxy-amine adduct, available from Ajinmoto. [0226] Cab-O-Sil 720: Fumed silica which has been surface treated with polydimethylsiloxane (PDMS) available from Cabot Corporation. [0227] Clearstrength® XT100: Core-shell toughening agent (methylmethacrylate-butadiene-styrene, MBS) available from Arkema Inc. [0228] Aerosil R202: Fumed silica, available from Degussa. [0229] Omyacarb 4HD: Calcium carbonate filler, available from Omya. [0230] Luzenac 2: Talcum, available from Rio Tinto. [0231] PM182: Premix of Epoxy (DER331), fumed silica and organic acid, available from Henkel. [0232] Printex L: Carbon black powder in 20% DER 331, available from Orion and Cabot. [0233] EMIM-MS: 1-Ethyl-3-methylimidazolium methansulfonate, available from TCI America Inc. [0234] PEG400: Polyethylene glycol, available from Sigma Aldrich. [0235] Gransurf 77 PEG-10 Dimethicone, available from Grant Industries.

Example 1

[0236] The formulation described in Table 1 hereinbelow was formed under mixing.

TABLE-US-00001 TABLE 1 Ingredients Wt. % of Composition DER 331 26.23 TMP 19.64 Omyacarb 4HD 39.76 Luzenac 2 4.7 Aerosil R202 2.07 Premix 182 0.28 Ajicure PN-H 0.85 EMIM MS 6.00 Printex L 0.47

[0237] The application substrate for the following Example 1 was aluminium (AA6016) having a thickness of 1 mm and Steel having a thickness 1.5 mm. The substrate was cut into samples of 2.5 cm×10 cm (1″×4″) in size for tensile testing. Tensile lap shear (TLS) test was performed according to test method describe on page 4.

[0238] The applied one-part (1K) adhesive composition was cured in the overlapping region by the application of a temperature 100° C. for 30 minutes. Subsequently, the samples were stored at 25° C. with 20% humidity in a climate chamber.

[0239] Tensile lap shear strength was investigated after said 24 hour storage period both prior and subsequent to the application of a constant potential of 50V across the adhesive layer for a duration of 20 minutes. The results are documented in Table 2 herein below.

TABLE-US-00002 TABLE 2 Initial Bond Bond Strength Strength after 50 V, Substrate (MPa) 20 minutes (MPa) Steel 12.78 (±0.58) 6.14 (±0.50) Aluminium 12.58 (±1.02) 3.22 (±0.28)

[0240] For the adhesively bonded aluminium substrate (AA6016), lap shear strength (MPa) was investigated under two conditions: a) a constant potential (75 V) was applied across the overlapping bonded area of sample substrates for different time periods up to and including 120 minutes; and, b) different potentials were applied across the overlapping bonded region of sample substrates for a fixed period of time (30 minutes) at each applied potential. The results of these investigations are given in FIGS. 3a and 3b appended hereto.

[0241] 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.

[0242] The lap shear was measured after one day, seven days, 14 days, 28 days and 60 days. The results are documented in Table 3 herein below.

TABLE-US-00003 TABLE 3 Initial Bond Bond Strength Strength after 75 V, Aluminium (MPa) 1 hour (MPa) 1 day 12.58 (±1.0) 3.22 (±0.3) 7 days 12.61 (±0.4) 3.60 (±1.3) 14 days 13.03 (±1.2) 4.97 (±1.2) 28 days 11.92 (±1.4) 3.10 (±0.8) 60 days 13.57 (±1.0) 4.32 (±1.1)

[0243] The stability results are illustrated in FIG. 4. FIG. 4 illustrates adhesion properties and debonding effect on aluminium. 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 2

[0244] The formulation described in Table 4 herein below was formed under mixing.

TABLE-US-00004 TABLE 4 Ingredient Wt. % of Composition DER 337-X80 60.97 Dyhard 100SH 1.91 1-methylimidazole 0.10 EMIM-MS 15.37 PEG 400 4.57 Gransurf 77 0.42 Cab-o-sil TS 720 2.50 Clearstrength XT100 14.17

[0245] The application substrate for the following Example 1 was aluminium (AA6016) having a thickness of 1.25 mm. The substrate was cut into samples of 2.5 cm×10 cm (1″×4″) in size for tensile testing. Tensile lap shear (TLS) test was performed according to test method describe on page 4.

[0246] The applied one-part (1K) adhesive composition was cured in the overlapping region by the application of a temperature 180° C. for 30 minutes. The bonded structures were then stored at room temperature for 24 hours prior to initial tensile testing.

[0247] For each substrate, tensile lap shear strength was investigated after said 24-hour storage period both prior and subsequent to the application of a constant potential of 50V across the adhesive layer for a duration of 20 minutes. The results are documented in Table 5 herein below.

TABLE-US-00005 TABLE 5 Initial Bond Bond Strength Strength after 50 V, Substrate (MPa) 20 minutes (MPa) Aluminium 7.11 (±0.6) 1.01 (±1.36) Stainless Steel 7.35 (±0.9) 0.73 (±1.11)

[0248] Stability test was conducted for the composition of example 2. For this test, normal lap shear samples were prepared and cured at 180° C. for 30 min. Aluminium (thickness of 1 mm) and steel (thickness of 1.5 mm) substrates were used. Subsequently, the samples were stored at 25° C. with 20% humidity in a climate chamber.

[0249] The lap shear was measured after one day, eight days, 15 days, 29 days and 50 days. The results are documented in Tables 6 and 7 herein below.

TABLE-US-00006 TABLE 6 Initial Bond Bond Strength Strength after 75 V, Aluminium (MPa) 1 hour (MPa) 1 day 8.99 (±0.52) 2.99 (±0.91) 8 days 7.89 (±0.50) 1.35 (±0.09) 15 days 7.86 (±0.27) 1.41 (±0.40) 29 days 6.55 (±0.81) 0.42 (±0.09) 50 days 6.78 (±0.86) 0.52 (±0.06)

TABLE-US-00007 TABLE 7 Initial Bond Bond Strength Strength after 75 V, Steel (MPa) 1 hour (MPa) 1 day 7.61 (±0.79) 2.42 (±0.75) 8 days 7.93 (±0.67) 2.54 (±0.90) 15 days 6.80 (±0.62) 0.17 (±0.05) 29 days 5.70 (±0.23) 0.37 (±0.05) 50 days 7.30 (±0.65) 0.33 (±0.16) 85 days 8.23 (±0.81) 0.22 (+0.13)

[0250] The stability results are illustrated in FIGS. 5 and 6. FIGS. 5 an 6 illustrate adhesion properties and debonding effect on aluminium. 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 3

[0251] The formulation described in Table 6 herein below was formed under mixing.

TABLE-US-00008 TABLE 6 Ingredient Wt. % of Composition DER 337-X80 73.16 Dyhard 100SH 2.29 1-methylimidazole 0.12 PEG400 5.48 Gransurf 77 0.50 1-allyl-3-methylimidazolium bis 18.45 (trifluoromethylsulfonyl)imide)

[0252] The application substrate for the following Example 1 was aluminium (AA6016) having a thickness of 1.25 mm inch. The substrate was cut into samples of 2.5 cm×10 cm (1″×4″) in size for tensile testing. Tensile lap shear (TLS) test was performed according to test method describe on page 4.

[0253] The applied one-part (1K) adhesive composition was cured in the overlapping region by the application of a temperature 180° C. for 30 minutes. Subsequently, the samples were stored at 25° C. with 20% humidity in a climate chamber.

[0254] For each substrate, tensile lap shear strength was investigated after said 24-hour storage period both prior and subsequent to the application of a constant potential of 50V across the adhesive layer for a duration of 20 minutes. The results are documented in Table 7 herein below.

TABLE-US-00009 TABLE 7 Initial Bond Bond Strength Strength after 50 V, Substrate (MPa) 20 minutes (MPa) Aluminium 5.47 (±1.75) 1.15 (±0.46)

Example 4

[0255] The formulation described in Table 8 herein below was formed under mixing.

TABLE-US-00010 TABLE 8 Wt. % of Ingredient Composition TMP 21.80 Omyacarb 4HD 39.21 Luzenac 2 4.87 Aerosil R 202 2.04 Premix 182 0.28 Aijcure PN-H 0.84 Reactint Black X95AB 2.32 EMIM MS 4.63 D.E.R 337 24.01

[0256] The application substrate for the following Example 1 was aluminium (AA6016) having a thickness of 1.25 mm. The substrate was cut into samples of 2.5 cm×10 cm (1″×4″) in size for tensile testing. Tensile lap shear (TLS) test was performed according to test method describe on page 4.

[0257] The applied one-part (1K) adhesive composition was cured in the overlapping region by the application of a temperature 100° C. for 30 minutes. Subsequently, the samples were stored at 25° C. with 20% humidity in a climate chamber.

[0258] For each substrate, tensile lap shear strength was investigated after said 24 hour storage period both prior and subsequent to the application of a constant potential of 50V across the adhesive layer for a duration of 20 minutes. The results are documented in Table 9 herein below.

TABLE-US-00011 TABLE 9 Initial Bond Bond Strength Strength after 50 V, Substrate (MPa) 20 minutes (MPa) Aluminium 2.78 (±0.08) 0.64 (±0.34)

Example 5

[0259] The formulation described in Table 10 herein below was formed under mixing.

TABLE-US-00012 TABLE 10 Exam- Exam- Exam- Exam- Exam- Ingredient ple 5a ple 5b ple 5c ple 5d ple 5e TMP 20.33 20.97 20.75 19.71 19.71 Omyacarb 4HD 41.16 42.44 42.01 39.89 39.89 Luzenac 2 4.86 5.01 4.96 4.71 4.71 Aerosil R 202 2.14 2.2 2.18 2.03 2.03 Premix 182 0.29 0.3 0.29 0.28 0.28 Aijcure PN-H 0.88 0.9 0.9 0.85 0.85 GPX 801 (Cabot) 0.10 0.1 0.11 0.1 0.10 EMIM MS 3.00 0.0 1.00 6.00 EMIM dicyanoamide 6.00 D.E.R 331 27.23 28.08 27.79 26.93 26.93

[0260] The application substrate for the following Example 1 was aluminium (AA6016) having a thickness of 1.25 mm. The substrate was cut into samples of 2.5 cm×10 cm (1″×4″) in size for tensile testing. Tensile lap shear (TLS) test was performed according to test method describe on page 4.

[0261] The applied one-part (1K) adhesive composition was cured in the overlapping region by the application of a temperature 100° C. for 30 minutes. Subsequently, the samples were stored at 25° C. with 20% humidity in a climate chamber.

[0262] For each substrate, tensile lap shear strength was investigated after said 24-hour storage period both prior and subsequent to the application of a constant potential of 50V across the adhesive layer for a duration of 20 minutes. The results for example 5a are documented in Table 11 herein below and results for examples 5b-5d in Table 12 below.

TABLE-US-00013 TABLE 11 Initial Bond Bond Strength Strength after 50 V, Substrate (MPa) 20 minutes (MPa) Aluminium 15.86 (±0.62) 2.39 (±0.1)

TABLE-US-00014 TABLE 12 Initial Bond Bond Strength Substrate Strength after 30 V, Aluminium (MPa) 20 minutes (MPa) Example 5b 13.95 (±0.62) Example 5c 13.66 (±1.27) 5.08 (±2.30) Example 5d 11.35 (±1.58) 0.27 (±0.10) Example 5e  8.91 (±0.57) 1.99 (±0.41)

[0263] The samples were prepared on nickel substrate and cured at 100° C. for 30 min and stored at 20% Rh 25° C. for a longer period. The results are documented in table 13 below.

TABLE-US-00015 TABLE 13 1 day 1 day 7 days 7 days Initial bond Bond strength Initial bond Bond strength Nickel strength after 30 V strength after 30 V Substrate (MPa) 20 min (MPa) (MPa) 20 min (MPa) Example 5a 8.58 (±1.15) 0.33 10.11 (±1.91) 0.47

[0264] The aging effect of Example 5a and Example 5d were studied. Aluminum Lap Shear Strength (LSS) samples were prepared and stored in an oven at 140° C. over a longer period. The samples were tested without applying a voltage and after applying a voltage. The table 14 below and FIG. 7 illustrate the results. It is noted that the initial strength did not change and the debonding effect stayed constant.

TABLE-US-00016 TABLE 14 Example 5a Example 5a Example 5d Example 5d Initial bond Bond strength Initial bond Bond strength Storage strength after 30 V strength after 30 V time (MPa) 20 min (MPa) (MPa) 20 min (MPa) 24 h/140° C. 19.87 (±0.77) 3.52 (±1.15) 19.86 (±1.15) 0.90 (±0.14)  6 d/140° C. 21.18 (±0.53) 2.88 (±1.87) 20.20 (±3.31) 1.46 (±0.51) 14 d/140° C. 19.88 (±0.50) 3.75 (±0.67) 21.04 (±0.72) 1.87 (±0.34) 21 d/140° C. 18.94 (±0.53) 4.61 (±0.19) 20.59 (±0.92) 1.94 (±0.28)

[0265] The aging effect of Example 5d was also studied under different aging conditions (20% RH 25° C.). Samples were prepared on Aluminium AA 6016 and stainless steel 1.4301 and cured at 100° C. for 30 minutes. The samples were stored at 20% Rh under 25° C. for a longer period. The results are illustrated in table 15 below and FIG. 8.

TABLE-US-00017 TABLE 15 Example 5D Example 5D Bond strength Storage Initial bond after 75 V time strength (MPa) 20 min (MPa)  2 d 8.81 (±0.55) 0.42 (±0.13)  7 d 9.63 (±1.46) 0.44 (±0.10) 14 d 11.24 (±2.24) 0.55 (±0.03) 21 d 10.51 (±0.72) 0.42 (±0.08) 28 d 10.61 (±1.71) 0.97 (±0.15) 56 d 12.28 (±0.82) 1.48 (±0.50) 134 d  12.76 (±0.30) 0.00 steel

Example 6

[0266] The effect of electrically non-conductive filler was investigated in this example. Composition comprising both electrically non-conductive filler and an electrolyte (examples 6a) was compared to a composition without an electrolyte (example 6b). The composition details are in table 16 below and the results are illustrated in Table 17 below.

TABLE-US-00018 TABLE 16 Example 6a Example 6b TMP 14.71 20.97 Omyacarb 4HD 39.89 42.44 Luzenac 2 4.71 5.01 Aerosil R 202 2.07 2.2 Premix 182 0.28 0.3 Aijcure PN-H 0.85 0.9 GPX 801 (Cabot) 0.1 0.1 EMIM MS 6.0 0.0 D.E.R 331 26.39 28.08

TABLE-US-00019 TABLE 17 Initial value 30 V 20 min Example 6a 11.35 (±1.58) 0.27 (±0.1) Example 6b 8.93 (±0.68) 11.82 (±2.19)

[0267] The results are also illustrated in FIG. 9. Example 6b without electrolyte showed no debonding effect.

[0268] 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.