USE OF TOUGHNESS IMPROVERS FOR INCREASING THE MAXIMUM LINEAR EXPANSION OF SINGLE-COMPONENT HEAT-CURING EPOXY RESIN COMPOSITIONS

Abstract

Methods in which toughness improvers based on terminally blocked polyurethane prepolymers are used to increase the maximum linear expansion of single component heat-curing epoxy resin compositions, in particular for joining substrates having different thermal expansion coefficients, in particular in the framework of transport agents or white goods.

Claims

1. A method comprising: adding at least one toughness improver D to a one-component thermosetting epoxy resin composition in an amount effective to increase the maximum linear expansion Max. elongation of the one-component thermosetting epoxy resin composition, wherein the one-component thermosetting epoxy resin composition comprises: a) at least one epoxy resin A having an average of more than one epoxy group per molecule, and b) at least one latent curing agent for epoxy resins B; where the weight ratio of the at least one epoxy resin A having an average of more than one epoxy group per molecule to the at least one toughness improver D is 0.3-2.2; the toughness improver D is a terminally blocked polyurethane prepolymer of the formula (I): ##STR00016## where R.sup.1 is a p-valent radical of a linear or branched polyurethane prepolymer terminated by isocyanate groups after the removal of the terminal isocyanate groups, p has a value of 2 to 8, and R.sup.2 is a blocking group which is detached at a temperature above 100 C., where R.sup.2 is not a substituent selected from the group consisting of ##STR00017## where R.sup.12 is an alkylene group which has 2 to 5 carbon atoms and optionally has double bonds or is substituted, or is a phenylene group or a hydrogenated phenylene group, especially -caprolactam after removal of the NH proton, and R.sup.19 represents bisphenols, after removal of a hydroxyl group; and the maximum linear expansion Max. elongation is determined in a lap shear test during the cooling of a heated cured lap shear specimen.

2. The method of claim 1, wherein R.sup.2 is independently a substituent selected from the group consisting of ##STR00018## where R.sup.5, R.sup.6, R.sup.7 and R.sup.8 are each independently an alkyl or cycloalkyl or aralkyl or arylalkyl group, or R.sup.5 together with R.sup.6, or R.sup.7 together with R.sup.8, form part of a 4- to 7-membered, optionally substituted ring; R.sup.9, R.sup.9 and R.sup.10 are each independently an alkyl or aralkyl or arylalkyl group or an alkyloxy or aryloxy or aralkyloxy group; R.sup.11 is an alkyl group; R.sup.13 and R.sup.14 are each independently an alkylene group which has 2 to 5 carbon atoms and optionally has double bonds or is substituted, or a phenylene group or a hydrogenated phenylene group; R.sup.15, R.sup.16 and R.sup.17 are each independently H or an alkyl group or an aryl group or an aralkyl group; R.sup.18 is an aralkyl group or is a mono- or polycyclic, substituted or unsubstituted aromatic group optionally having aromatic hydroxyl groups; R.sup.4 is a radical of an aliphatic, cycloaliphatic, aromatic or araliphatic epoxide containing a primary or secondary hydroxyl group after the removal of the hydroxyl and epoxy groups; and m has a value of 1, 2 or 3.

3. The method of claim 1, wherein R.sup.2 is independently a substituent selected from the group consisting of ##STR00019## where R.sup.5, R.sup.6, R.sup.7 and R.sup.8 are each independently an alkyl or cycloalkyl or aralkyl or arylalkyl group, or R.sup.5 together with R.sup.6, or R.sup.7 together with R.sup.8, form part of a 4- to 7-membered, optionally substituted ring; R.sup.15, R.sup.16 and R.sup.17 are each independently H or an alkyl group or an aryl group or an aralkyl group; and R.sup.18 is an aralkyl group or is a mono- or polycyclic, substituted or unsubstituted aromatic group optionally having aromatic hydroxyl groups.

4. The method of claim 1, wherein the weight ratio of the at least one epoxy resin A having an average of more than one epoxy group per molecule to the at least one toughness improver D is 0.4-2.0.

5. The method of claim 1, wherein R.sup.1 is a p-valent radical of a linear or branched polyurethane prepolymer terminated by isocyanate groups after the removal of the terminal isocyanate groups, and the polyurethane prepolymer is prepared from at least one diisocyanate or triisocyanate and from a polymer Q.sub.PM having terminal amino, thiol or hydroxyl groups.

6. The method of claim 5, wherein the polymer Q.sub.PM having terminal amino, thiol or hydroxyl groups comprises polyols, each having an average molecular weight that is between 600 and 6000 daltons, the polyols being selected from the group consisting of polyethylene glycols, polypropylene glycols, polyethylene glycol-polypropylene glycol block polymers, polybutylene glycols, polytetramethylene ether glycols, hydroxyl-terminated polybutadienes, hydroxyl-terminated butadiene-acrylonitrile copolymers and mixtures thereof.

7. The method of claim 6, wherein the polymer Q.sub.PM having terminal amino, thiol or hydroxyl groups comprises polyols, each having an average molecular weight that is between 600 and 6000 daltons, the polyols being selected from the group consisting of polytetramethylene ether glycols and hydroxyl-terminated polybutadienes, wherein the weight ratio of polytetramethylene ether glycol to hydroxyl-terminated polybutadiene is in the range from 100/0 to 70/30.

8. The method of claim 1, wherein the maximum linear expansion Max. elongation is measured in a lap shear test at a strain rate V.sub.st of 0.52 mm/min.

9. The method of claim 1, wherein the temperature of the lap shear specimen in the lap shear test is 190 C. at the start of the measurement and the lap shear specimen is cooled at the start of the measurement at a cooling rate of 40 C./min to a temperature of 25 C. and then left at that temperature.

10. The method of claim 1, wherein the lap shear test is a lap shear test having lap shear test specimens having the following features: steel sheets having the dimensions of 25 mm100 mm1.5 mm, bonding area of the cured one-component thermosetting epoxy resin composition having the dimensions of 10 mm25 mm with a thickness of 1.5 mm.

11. The method of claim 1, wherein the maximum linear expansion Max. elongation is 2.145 mm.

12. The method of claim 1, wherein a maximum force measured is 6000 N.

13. The method of claim 1, wherein a force measured on attainment of the maximum linear expansion Max. elongation of 2.145 mm is 4000 N.

14. The method of claim 1, wherein the latent curing agent for epoxy resins B is selected from the group consisting of dicyandiamide, guanidines, anhydrides of polybasic carboxylic acids, dihydrazides and aminoguanidines.

15. The method of claim 1, wherein the one-component thermosetting epoxy resin composition is a thermosetting epoxy resin adhesive, and the method further comprises either applying the thermosetting epoxy resin adhesive to at least one substrate to bond substrates of a motor vehicle construction, or applying the thermosetting epoxy resin adhesive to at least one substrate to bond substrates of a sandwich panel construction.

Description

EXAMPLES

[0209] Some examples which further illustrate the invention, but which are not intended to restrict the scope of the invention in any way, are cited below.

Determination of Isocyanate Content

[0210] The isocyanate content was determined in % by weight by means of a back-titration with di-n-butylamine used in excess and 0.1 M hydrochloric acid. All determinations were conducted in a semi-manual manner on a Mettler-Toledo DL50 Graphix titrator with automatic potentiometric endpoint determination. For this purpose, 600-800 mg in each case of the sample to be determined was dissolved while heating in a mixture of 10 ml of isopropanol and 40 ml of xylene, and then reacted with a solution of dibutylamine in xylene. Excess di-n-butylamine was titrated with 0.1 M hydrochloric acid, and the isocyanate content was calculated therefrom.
Maximum Linear Expansion (Max. Elongation) and Maximum Force (Max. Force)
Maximum linear expansion (Max. elongation) and maximum force (Max. force) were determined as described above under Description of test method for maximum linear expansion (Max. elongation) and maximum force. A triple determination was conducted for each epoxy resin composition. The maximum linear expansion Max. elongation was determined from the distance traversed. The measurement was evaluated by taking, from the measurement protocol, the averages of the maximum linear expansion Max. elongation (.sub.M2) at maximum force (.sub.M2).

Tensile Strength, Elongation at Break and Modulus of Elasticity (DIN EN ISO 527)

[0211] An adhesive sample was pressed between two Teflon papers to a layer thickness of 2 mm. After curing at 175 C. for 35 min, the Teflon papers were removed and the specimens were die-cut to the DIN standard state. The test specimens were examined under standard climatic conditions at a strain rate of 2 mm/min. Tensile strength, elongation at break and the 0.05-0.25% modulus of elasticity were determined to DIN EN ISO 527.

Lap Shear Strength (LSS) (DIN EN 1465)

[0212] Cleaned test specimens of H420+Z steel (thickness 1.2 mm) that had been reoiled with Anticorit PL 3802-39S were bonded with the adhesive over a bonding area of 2510 mm with glass beads as spacer in a layer thickness of 1.5 mm, and cured under the curing conditions specified.
Curing conditions: a) 35 min at oven temperature 175 C.
Lap shear strength was determined on a tensile tester at a strain rate of 10 mm/min in a triple determination to DIN EN 1465.

T-Peel Strength (DIN 53281)

[0213] 13025 mm test sheets of DC-04+ZE steel (thickness 0.8 mm) were prepared. Test sheets were processed at a height of 30 mm with a suitable die-cutting machine (90). The cleaned 10025 mm surfaces that had been reoiled with Anticorit PL 3802-39S were bonded with the adhesive with glass beads as spacer in a layer thickness of 0.3 mm, and cured for a dwell time of 35 min from attainment of an oven temperature of 175 C. T-peel strength was determined on a tensile tester at a strain rate of 100 mm/min in a duplicate determination as peel force in N/mm in the traversed distance range from to of the distance covered.

Impact Peel Strength (to ISO 11343)

[0214] The specimens were produced with the adhesive and DC04+ZE steel with dimensions of 90200.8 mm. The bonding area here was 2030 mm at a layer thickness of 0.3 mm with glass beads as spacer. Impact peel strength was measured in each case at the temperatures specified (RT=23 C., 30 C.) as a triple determination on a Zwick 450 impact pendulum at 2 m/s. The impact peel strength reported is the average force in N/mm under the measurement curve from 25% to 90% to ISO11343.
The adhesives were cured at oven temperature 175 C. for 35 min.

Viscosity

[0215] Viscosity measurements of the adhesives were effected 1 d after production on an Anton Paar MCR 101 rheometer by oscillation using a plate-plate geometry at a temperature of 25 C. or 50 C. with the following parameters: 5 Hz, 1 mm gap, plate-plate distance 25 mm, 1% deformation.
The following commercial products were used for the production of impact modifiers 1 to 9:

TABLE-US-00001 TABLE 1 Compound Description Manufacturer BHT (Ionol CP) Butylhydroxytoluene stabilizer Evonik PolyTHF 2000 Difunctional polytetramethylene BASF ether glycol having a molar mass of 2000 g/mol Poly bd R45V Hydroxyl-terminated polybutadiene Cray Valley having a molar mass of 2800 g/mol, OH functionality about 2.4-2.6 Vestanat IPDI Isophorone diisocyanate Evonik Dibutyltin Catalyst Thorson dilaurate 4-Methoxyphenol Blocking agent Solvay Phenol Blocking agent Sigma-Aldrich Caprolactam Blocking agent Sigma-Aldrich Methyl ethyl Blocking agent Sigma-Aldrich ketoxime 2-Benzoxazol- Blocking agent Synthesia inone 3,5-Dimethyl- Blocking agent Chemtura pyrazole 2,2-Diallylbis- Blocking agent Sigma-Aldrich phenol A

Example 1: Impact Modifier SM1 (Phenol [1.2 Eq.] as Blocking Agent, PolyTHF2000/Poly BD R45HTLO Backbone)

[0216] 225 g of PolyTHF 2000, 225 g of Poly bd R45V and 2.25 g of BHT as stabilizer were dewatered at 90 C. under reduced pressure with minimal stirring for 1 h. Subsequently, 90.83 g of isophorone diisocyanate (IPDI) and 0.059 g of dibutyltin dilaurate (DBTDL) were added. The reaction was conducted under moderate stirring at 90 C. under reduced pressure for 2 h in order to obtain an isocyanate-terminated polymer: Measured free NCO content: 3.05%.
To the resultant NCO-terminated polymer were added 0.117 g of dibutyltin dilaurate (DBTDL) and 44.35 g of phenol, and the isocyanate groups were depleted by reaction at 110 C. under reduced pressure for 5 h. Measured free NCO content: (directly after preparation) 0.53%, (1 day after preparation) 0.24%.

Example 2: Impact Modifier SM2 (4-Methoxyphenol [1.2 Eq.] as Blocking Agent, PolyTHF2000/PolyBD R45V as Backbone)

[0217] 200 g of PolyTHF 2000, 200 g of Poly bd R45V and 2.00 g of BHT as stabilizer were dewatered at 90 C. under reduced pressure with minimal stirring for 1 h. Subsequently, 80.64 g of isophorone diisocyanate (IPDI) and 0.053 g of dibutyltin dilaurate (DBTDL) were added. The reaction was conducted under moderate stirring at 90 C. under reduced pressure for 2 h in order to obtain an isocyanate-terminated polymer: Measured free NCO content: 2.81%.
To the resultant NCO-terminated polymer were added 0.106 g of dibutyltin dilaurate (DBTDL) and 47.93 g of 4-methoxyphenol (HQMME), and the isocyanate groups were depleted by reaction at 110 C. under reduced pressure for 5 h. Measured free NCO content: (directly after preparation) 2.82%, (1 day after preparation) 0.09%.

Example 3: Impact Modifier SM3 (4-Methoxyphenol [1.2 Eq.] as Blocking Agent, PolyTHF 2000 as Backbone)

[0218] 350 g of PolyTHF 2000 and 3.50 g of BHT as stabilizer were dewatered at 90 C. under reduced pressure with minimal stirring for 1 h. Subsequently, 77.82 g of isophorone diisocyanate (IPDI) and 0.048 g of dibutyltin dilaurate (DBTDL) were added. The reaction was conducted under moderate stirring at 90 C. under reduced pressure for 2 h in order to obtain an isocyanate-terminated polymer: Measured free NCO content: 3.35%.
To the resultant NCO-terminated polymer were added 0.096 g of dibutyltin dilaurate (DBTDL) and 50.76 g of 4-methoxyphenol (HQMME), and the isocyanate groups were depleted by reaction at 110 C. under reduced pressure for 5 h. Measured free NCO content: (directly after preparation) 0.48%, (1 day after preparation) 0.23%.
Viscosity (1 day after preparation): 422 Pa*s at 25 C., 82 Pa*s at 50 C.

Example 4: Impact Modifier SM4 (2-Benzoxazolinone [1.2 Eq.] as Blocking Agent, PolyTHF 2000 as Backbone)

[0219] 400 g of PolyTHF 2000 and 4.50 g of BHT as stabilizer were dewatered at 90 C. under reduced pressure with minimal stirring for 1 h. Subsequently, 88.62 g of isophorone diisocyanate (IPDI) and 0.055 g of dibutyltin dilaurate (DBTDL) were added. The reaction was conducted under moderate stirring at 90 C. under reduced pressure for 2 h in order to obtain an isocyanate-terminated polymer: Measured free NCO content: 3.61%.
To the resultant NCO-terminated polymer were added 0.110 g of dibutyltin dilaurate (DBTDL) and 59.64 g of benzoxazolinone, and the isocyanate groups were depleted by reaction at 110 C. under reduced pressure for 3 h. Measured free NCO content: 0.24%.

Example 5: Impact Modifier SM5 (3,5-Dimethylpyrazole [1.2 Eq.] as Blocking Agent, PolyTHF 2000, Poly bd R45V as Backbone)

[0220] 225 g of PolyTHF 2000, 225 g of Poly bd R45V and 2.25 g of BHT as stabilizer were dewatered at 90 C. under reduced pressure with minimal stirring for 1 h. Subsequently, 77.82 g of isophorone diisocyanate (IPDI) and 0.058 g of dibutyltin dilaurate (DBTDL) were added. The reaction was conducted under moderate stirring at 90 C. under reduced pressure for 2 h in order to obtain an isocyanate-terminated polymer: Measured free NCO content: 3.08%.
To the resultant NCO-terminated polymer were added 0.116 g of dibutyltin dilaurate (DBTDL) and 38.11 g of 3,5-dimethylpyrazole, and the isocyanate groups were depleted by reaction at 110 C. under reduced pressure for 2 h. Measured free NCO content: 0.0%.

Example 6: Impact Modifier SM6 (Dibutylamine [1.0 Eq.] as Blocking Agent, PolyTHF 2000, Poly bd R45V as Backbone)

[0221] 175 g of PolyTHF 2000, 175 g of Poly bd R45V and 1.75 g of BHT as stabilizer were dewatered at 90 C. under reduced pressure with minimal stirring for 1 h. Subsequently, 70.56 g of isophorone diisocyanate (IPDI) and 0.046 g of dibutyltin dilaurate (DBTDL) were added. The reaction was conducted under moderate stirring at 90 C. under reduced pressure for 2 h in order to obtain an isocyanate-terminated polymer: Measured free NCO content: 2.90%.
To the resultant NCO-terminated polymer were added 0.92 g of dibutyltin dilaurate (DBTDL) and 37.52 g of dibutylamine, and the isocyanate groups were depleted by reaction at 70 C. under reduced pressure for 3 h. Measured free NCO content: 0.0%.

Example 7: Impact Modifier SM7 (MEKO [1.2 Eq.] as Blocking Agent)

[0222] 200 g of PolyTHF 2000, 200 g of Poly BD R45V and 2.00 g of BHT as stabilizer were dewatered at 90 C. under reduced pressure with minimal stirring for 1 h. Subsequently, 80.74 g of isophorone diisocyanate (IPDI) and 0.052 g of dibutyltin dilaurate (DBTDL) were added. The reaction was conducted under moderate stirring at 90 C. under reduced pressure for 2 h in order to obtain an isocyanate-terminated polymer: Measured free NCO content: 2.91%.
To the resultant NCO-terminated polymer were added 0.104 g of dibutyltin dilaurate (DBTDL) and 34.82 g of 2-butane oxime (MEKO), and the isocyanate groups were depleted by reaction at 110 C. under reduced pressure for 1 h. Measured free NCO content: 0.00%.

Example 8: Impact Modifier SM8 (2,2-Diallylbisphenol a [1.2 Eq.] as Blocking Agent)

[0223] 290 g of PolyTHF 2000 and 2.90 g of BHT as stabilizer were dewatered at 90 C. under reduced pressure with minimal stirring for 1 h. Subsequently, 64.25 g of isophorone diisocyanate (IPDI) and 0.046 g of dibutyltin dilaurate (DBTDL) were added. The reaction was conducted under moderate stirring at 90 C. under reduced pressure for 2 h in order to obtain an isocyanate-terminated polymer: Measured free NCO content: 3.36%.
To the resultant NCO-terminated polymer were added 0.092 g of dibutyltin dilaurate (DBTDL) and 104.76 g of 2,2-diallylbisphenol, and the isocyanate groups were depleted by reaction at 110 C. under reduced pressure for 5 h. Measured free NCO content after 5 h: 0.74%.
Measured free NCO content the next day at RT: 0.36%.

Example 9: Impact Modifier SM9 (Caprolactam [1.2 Eq.] as Blocking Agent)

[0224] 200 g of PolyTHF 2000, 200 g of Poly bd R45V and 2.00 g of BHT as stabilizer were dewatered at 90 C. under reduced pressure with minimal stirring for 1 h. Subsequently, 80.74 g of isophorone diisocyanate (IPDI) and 0.053 g of dibutyltin dilaurate (DBTDL) were added. The reaction was conducted under moderate stirring at 90 C. under reduced pressure for 2 h in order to obtain an isocyanate-terminated polymer: Measured free NCO content: 3.026%.
To the resultant NCO-terminated polymer were added 0.106 g of dibutyltin dilaurate (DBTDL) and 47.01 g of caprolactam, and the isocyanate groups were depleted by reaction at 110 C. under reduced pressure for 3 h. Measured free NCO content: 0.00%.

Example Adhesives 1 to 9

[0225] The impact modifiers SM1 to SM9 prepared in examples 1 to 9 were each used for production of epoxy resin compositions according to table 2.
Compositions and proportions for epoxy resin compositions containing one of impact modifiers 1 to 9 are summarized in table 2. SM-X relates to the impact modifiers prepared above SM1, SM2, etc.

TABLE-US-00002 TABLE 2 Parts by Chemical weight composition Function 23.0 Epoxy resin based on bisphenol Epoxy resin A, liquid matrix 12.0 Epoxy resin based on bisphenol Epoxy resin A, solid matrix 0.5 p-tert-Butylphenyl glycidyl ether Reactive diluent 50.0 Blocked polyurethane, SM-X Impact modifier 2.43 Dicyandiamide Curing agent 0.13 Urone Curing agent accelerator 5.0 CaCO.sub.3 Filler 6.0 Calcium oxide Moisture scavenger 8.0 Fumed silica Thixotropic agent Total: 107.06 Dicy index: 5.50 mol EP/dicy
The respective epoxy resin compositions were mixed in a planetary mixer in a batch size of 350 g. For this purpose, the mixing vessel was filled with the liquid components, followed by the solid components, and they were mixed at 70 C. under reduced pressure. During the mixing operation (about 45 min), the vacuum was broken several times and the mixing tool wiped clean. After a homogeneous mixture had been obtained, the epoxy resin composition was dispensed into cartridges and stored at room temperature.
Tables 3 and 4 show the results of the evaluation of the resultant epoxy resin compositions with the impact modifiers SM1-9.

TABLE-US-00003 TABLE 3 (Positive examples) Composition 1 2 3 4 5 6 7 Impact modifier SM1 SM2 SM3 SM4 SM5 SM6 SM7 Blocking Phenol HQMME HQMME 2-Benzoxa- 3,5- Dibutylamine MEKO agent zolinone Dimethylpyrazole Backbone PolyTHF2000 PolyTHF2000 PolyTHF2000 PolyTHF2000 PolyTHF2000Poly PolyTHF2000Poly PolyTHF 2000 Poly bd R45V Poly bd R45V bd R45V bd R45V PolyBD R45V Max. elongation 2.5 3.2 3.8 4.0 3.1 3.5 3.2 [mm] Max. force [N] 3151 1933 2304 3972 1178 2025 2503 Modulus of elasticity 336 236 256 433 156 183 264 [MPa] Tensile strength 16.5 12.9 15.0 16.4 5.6 7.9 10.6 [MPa] Elongation at break 141 108 154 115 40 83 47 [%] LSS [MPa] 17.1 16.1 17.1 14.6 12.1 15.2 15.8 T-peel [N/mm] 14.6 10.5 13.6 11.3 8.1 13.0 11.0 I-Peel [N/mm] 54.2 42.4 62.8 36.5 36.4 53.7 46.0 Viscosity [Pa * s] 25 C. 1738 1583 1470 1319 1716 1534 1636 50 C. 559 497 559 452 603 530 553

TABLE-US-00004 TABLE 4 (Negative examples) Composition 8 9 Impact modifier SM8 SM9 Blocking agent Diallylbis-phenol A Caprolactam Backbone PolyTHF2000 PolyTHF 2000 PolyBD R45V Max. elongation [mm] 0.5 0.4 Max. force [N] 166 179 Modulus of elasticity [MPa] 402 299 Tensile strength [MPa] 17.4 16.6 Elongation at break [%] 95 53 LSS [MPa] 17.8 15.3 T-peel [N/mm] 7.6 5.9 I-Peel [N/mm] RT 49.4 31.0 Viscosity [Pa * s] 25 C. 6387 1652 Viscosity [Pa * s] 50 C. 1326 511

Compositions 10-24

[0226] Impact modifiers SM2, SM3 and SM4 were used in different concentrations to produce adhesives according to table 5. The epoxy resin bisphenol A epoxy resin used is a mixture of 2 parts liquid epoxy resin based on bisphenol A and one part solid epoxy resin based on bisphenol A.
Tables 6-8 show the results of the evaluation of the resultant adhesives 10-25 with the impact modifiers SM2, SM3 and SM4.
The maximum linear expansion as a function of the proportion of the impact modifier is shown in FIGS. 2 to 4.

TABLE-US-00005 TABLE 5 Concentration series with SM2, SM3, SM4, *Weight ratio of epoxy resin A/toughness improver SM Composition 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Parts by weight Bisphenol A 70 60 55 46 30 10 60 55 46 30 10 60 46 30 10 Epoxy resin Impact 10 20 25 34 50 70 modifier SM2 Impact 20 25 34 50 70 modifier SM3 Impact 20 34 50 70 modifier SM4 Calcium carbonate 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 Calcium oxide 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 Fumed silica 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 Dicyandiamide 5.77 4.95 4.54 3.79 2.47 0.82 4.95 4.54 3.79 2.47 0.82 4.95 3.79 2.47 0.82 Urone 0.30 0.26 0.24 0.20 0.13 0.04 0.26 0.24 0.20 0.13 0.04 0.26 0.20 0.13 0.04 A/SM* 7 3 2.2 1.4 0.6 0.2 3 2.2 1.4 0.6 0.2 3 1.4 0.6 0.2

TABLE-US-00006 TABLE 6 Results for compositions 10-15 with SM2 Composition 10 11 12 13 14 15 SM2 pts. by wt. 10% 20% 25% 34% 50% 70% Max. elongation 1.40 1.70 2.16 2.40 3.30 5.20 [mm] Max. force [N] 3415 4164 4390 4072 3010 265 Modulus of 1860 1560 1320 966 291 2 elasticity [MPa] Tensile strength 38.5 34.5 29.8 25.5 15 1.8 [MPa] Elongation at 4 8 8 19 121 262 break [%] T-peel [N/mm] 2.6 8.9 10.9 11.4 11.3 4.8 I-Peel [N/mm] 10.4 27.5 40.8 41.6 43.2 22.4 23 C. I-Peel [N/mm] 4.8 26.4 33.5 44.3 51.7 41.3 30 C.

TABLE-US-00007 TABLE 7 Results for compositions 16-20 with SM3 Composition 16 17 18 19 20 SM3 pts. by wt. 20% 25% 34% 50% 70% Max. elongation [mm] 1.6 2.1 2.3 3.8 Composition Max. force [N] 2439 4459 3537 2303 uncured Modulus of elasticity 1430 1340 913 256 [MPa] Tensile strength 29.4 28.3 20.7 15 [MPa] Elongation at break 6 8 14 154 [%] T-peel [N/mm] 4.9 12.2 12.9 13.6 I-Peel [N/mm] 34.1 44.8 52.7 62.8 23 C. I-Peel [N/mm] 10.7 31.6 42.1 61.1 30 C.

TABLE-US-00008 TABLE 8 Results for compositions 21-24 with SM4 Composition 21 22 22 23 24 SM4 pts. by wt. 20% 25% 34% 50% 70% Max. elongation [mm] 1.6 1.9 2.2 3.2 Composition Max. force [N] 3261 4047 3974 3971 uncured Modulus of elasticity 1200 1190 914 433 [MPa] Tensile strength 25.9 28.4 25.8 16.4 [MPa] Elongation at break 7 11 21 115 [%] T-peel [N/mm] 2.6 3.4 7.9 11.3 I-Peel [N/mm] 15.2 30.2 37.9 36.5 23 C. I-Peel [N/mm] 6.3 30.5 41.6 33.8 30 C.