TWO-COMPONENT COMPOSITION WITH A HIGH DEGREE OF STRENGTH

Abstract

A composition including: —at least one silane group-containing polymer with a silicon content ranging from 0.6 to 2 wt. %, obtained by reacting at least one isocyanate group-containing polymer and at least one amino-, mercapto-, or hydroxysilane, —at least one liquid epoxy resin, and—at least one polyamine with at least three amine hydrogens which are reactive towards epoxy groups. The composition facilitates adhesives, coatings, or sealing compounds with a good storage stability, a fast curing time, even in the event of moisture or humidity, a surprisingly high degree of strength while having a high degree of elasticity, a high degree of resistance against further tearing, a high degree of resistance in particular against glycol/water mixtures, and a high degree of adhesion to many substrates. When used on metals such as steel or aluminum, the composition protects same against corrosion.

Claims

1. A composition comprising at least one polymer containing silane groups and having a silicon content in the range from 0.6% to 2% by weight, obtained from the reaction of at least one polymer containing isocyanate groups and at least one amino-, mercapto- or hydroxysilane, at least one liquid epoxy resin, and at least one polyamine having at least three amine hydrogens reactive toward epoxy groups.

2. The composition as claimed in claim 1, wherein the polymer containing silane groups has a silicon content in the range from 0.7% to 1.5% by weight.

3. The composition as claimed in claim 1, wherein the polymer containing silane groups has silane groups of the formula (I) ##STR00005## where n is 1 or 2 or 3, R.sup.1 is a linear or branched, monovalent hydrocarbyl radical having 1 to 5 carbon atoms, R.sup.2 is a linear or branched, divalent hydrocarbyl radical which has 1 to 12 carbon atoms and which optionally contains cyclic and/or aromatic moieties and optionally one or more heteroatoms, X is O or S or NR.sup.3 where R.sup.3 is a hydrogen atom or a linear or branched hydrocarbyl radical which has 1 to 20 carbon atoms and which optionally contains cyclic moieties, and which optionally contains an alkoxysilyl group or ether or carboxylic ester groups.

4. The composition as claimed in claim 1, wherein the polymer containing isocyanate groups has an NCO content in the range from 1.2% to 4% by weight.

5. The composition as claimed in claim 1, wherein the polymer containing isocyanate groups has been obtained from the reaction of at least one polyoxypropylene diol having an OH number in the range from 18 to 58 mg KOH/g, and optionally having terminal oxyethylene groups, and at least one diisocyanate.

6. The composition as claimed in claim 1, wherein the polymer containing isocyanate groups has aromatic isocyanate groups.

7. The composition as claimed in claim 1, wherein the amino-, mercapto- or hydroxysilane is an aminosilane.

8. The composition as claimed in claim 1, wherein the polyamine is selected from the group consisting of 1,5-diamino-2-methylpentane, 2,2(4),4-trimethylhexamethylenediamine, 1,2-diaminocyclohexane, 1,3-diaminocyclohexane, 1,4-diaminocyclohexane, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane, 2(4)-methyl-1,3-diaminocyclohexane, bis(4-aminocyclohexyl)methane, 2,5(2,6)-bis(aminomethyl)bicyclo[2.2.1]heptane, 1,3-bis(aminomethyl)benzene, polyoxypropylenediamines and polyoxypropylenetriamines with average molecular weight M.sub.n in the range from 200 to 500 g/mol, bis(hexamethylene)triamine, triethylenetetramine, tetraethylenepentamine, N,N′-bis(3-aminopropyl)ethylenediamine, N,N-dimethyldi(1,3-propylene)triamine, N-benzylethane-1,2-diamine, N-benzylpropane-1,2-diamine, N-benzyl-1,3-bis(aminomethyl)benzene, N-(2-phenylethyl)-1,3-bis(aminomethyl)benzene and the adduct of 1,5-diamino-2-methylpentane or propane-1,2-diamine with cresyl glycidyl ether.

9. The composition as claimed in claim 1, wherein it comprises a first component and a second component that are produced, packed and stored separately, wherein the polyamine is not in the same component as the liquid epoxy resin.

10. The composition as claimed in claim 1, wherein it additionally comprises at least one further constituent selected from aminosilanes, driers, accelerators, water, fillers and plasticizers.

11. A method comprising applying the composition as claimed in claim 1 as adhesive, sealant, coating or casting compound.

12. The method as claimed in claim 11, wherein the composition is used for the bonding of battery boxes.

13. A method of bonding, wherein the mixed composition as claimed in claim 1 is applied to at least one of the substrates to be bonded within the pot life, and the substrates are joined to give a bond within the open time, followed by the curing of the mixed composition.

14. A method of coating substrates or of filling cavities, wherein the mixed composition as claimed in claim 1 is applied to a substrate or used to fill a cavity within the pot life, and cures in situ.

15. An article obtained from the method of claim 11.

Description

EXAMPLES

[0211] Working examples are adduced hereinafter, which are intended to elucidate the invention described. The invention is of course not limited to these described working examples.

[0212] “Standard climatic conditions” (“SCC”) refer to a temperature of 23±1° C. and a relative air humidity of 50±5%.

[0213] Unless otherwise stated, the chemicals used were from Sigma-Aldrich Chemie GmbH.

[0214] Diethyl N-(3-trimethoxysilylpropyl)aminosuccinate was prepared from the reaction of diethyl maleate and 3-trimethoxysilylpropylamine.

[0215] Diisodecyl phthalate was used in the form of Palatinol® 10-P (from BASF).

[0216] Comparative examples are identified by (Ref.).

Preparation of Polymers Containing Silane Groups:

Polymer ST-1

[0217] With exclusion of moisture, 400 g of polyoxypropylene diol (Acclaim® 4200, OH number 28 mg KOH/g, from Covestro) and 52 g of diphenylmethane 4,4′-diisocyanate (Desmodur® 44 MC L, from Covestro) were heated to 80° C. with constant stirring and left at that temperature until the NCO content reached a value of 1.85% by weight.

[0218] Subsequently, 70.7 g of diethyl N-(3-trimethoxysilylpropyl)aminosuccinate was added and the mixture was stirred at 60° C. until it was no longer possible to detect any isocyanate by means of FT-IR spectroscopy. The resultant polymer containing silane groups was cooled down to room temperature and stored with exclusion of moisture. It was clear and liquid at room temperature, and had a calculated silicon content of 1.08% by weight.

Polymer ST-2

[0219] With exclusion of moisture, 513.3 g of polyoxypropylene diol (Acclaim® 4200, OH number 28 mg KOH/g, from Covestro), 256.7 g of ethylene oxide-terminated polyoxypropylene triol (Caradol® MD34-02, OH number 35 mg KOH/g, from Shell) and 64.2 g of toluene diisocyanate (Desmodur® T 80 P, from Covestro) were heated to 80° C. with constant stirring and left at that temperature until the NCO content reached a value of 1.5% by weight.

[0220] Subsequently, 105.8 g of diethyl N-(3-trimethoxysilylpropyl)aminosuccinate was added and the mixture was stirred at 60° C. until it was no longer possible to detect any isocyanate by means of FT-IR spectroscopy. The resultant polymer containing silane groups was cooled down to room temperature and stored with exclusion of moisture. It was clear and liquid at room temperature, and had a calculated silicon content of 0.90% by weight.

Polymer ST-3

[0221] With exclusion of moisture, 400 g of polyoxypropylene diol (Acclaim® 4200, OH number 28 mg KOH/g, from Covestro), 44.4 g of isophorone diisocyanate (Vestanat® IPDI, from Evonik) and 0.05 g of dibutyltin dilaurate were heated to 80° C. with constant stirring and left at that temperature until the NCO content reached a value of 1.9% by weight.

[0222] Subsequently, 74.8 g of diethyl N-(3-trimethoxysilylpropyl)aminosuccinate was added and the mixture was stirred at 60° C. until it was no longer possible to detect any isocyanate by means of FT-IR spectroscopy. The resultant polymer containing silane groups was cooled down to room temperature and stored with exclusion of moisture. It was clear and liquid at room temperature, and had a calculated silicon content of 1.15% by weight.

Polymer ST-4

[0223] With exclusion of moisture, 500.0 g of polyoxypropylene diol (Voranol® 2000 L, OH number 55.5 mg KOH/g, from Dow) and 88.7 g of toluene diisocyanate (Desmodur® T 80 P, from Covestro) were heated to 80° C. with constant stirring and left at that temperature until the NCO content reached a value of 3.4% by weight.

[0224] Subsequently, 167.5 g of diethyl N-(3-trimethoxysilylpropyl)aminosuccinate was added and the mixture was stirred at 60° C. until it was no longer possible to detect any isocyanate by means of FT-IR spectroscopy. The resultant polymer containing silane groups was cooled down to room temperature and stored with exclusion of moisture. It was clear and liquid at room temperature, and had a calculated silicon content of 1.8% by weight.

Polymer ST-5 (Ref.)

[0225] With exclusion of moisture, 250.0 g of polyoxypropylene diol (Voranol® 2000 L, OH number 55.5 mg KOH/g, from Dow), 250.0 g of polyoxypropylene diol (Voranol® P1010, OH number 110 mg KOH/g, from Dow) and 130.4 g of toluene diisocyanate (Desmodur® T 80 P, from Covestro) were heated to 80° C. with constant stirring and left at that temperature until the NCO content reached a value of 4.9% by weight.

[0226] Subsequently, 258.5 g of diethyl N-(3-trimethoxysilylpropyl)aminosuccinate was added and the mixture was stirred at 60° C. until it was no longer possible to detect any isocyanate by means of FT-IR spectroscopy. The resultant polymer containing silane groups was cooled down to room temperature and stored with exclusion of moisture. It was clear and liquid at room temperature, and had a calculated silicon content of 2.3% by weight.

Polymer ST-6 (Ref.)

[0227] With exclusion of moisture, 1000 g of polyoxypropylene diol (Acclaim® 12200, from Covestro; OH number 11.0 mg KOH/g), 122.8 g of diisodecyl phthalate, 43.6 g of isophorone diisocyanate (Vestanat® IPDI, from Evonik) and 0.12 g of dibutyltin dilaurate were heated to 90° C. with constant stirring and left at that temperature until the NCO content reached a value of 0.63% by weight.

[0228] Subsequently, 61.8 g of diethyl N-(3-trimethoxysilylpropyl)aminosuccinate was added and the mixture was stirred at 90° C. until it was no longer possible to detect any isocyanate by means of FT-IR spectroscopy. The resultant polymer containing silane groups (90% by weight in diisodecyl phthalate) was cooled down to room temperature and stored with exclusion of moisture. It was clear and liquid at room temperature, and had a calculated silicon content of 0.45% by weight (calculated for 100% by weight of polymer, without diisodecyl phthalate).

[0229] Polymers ST-1 to ST-4 have a silicon content according to the invention. Polymer ST-5 (Ref.) has a higher content and polymer ST-6 (Ref.) a lower content than the silicon content according to the invention. They serve as comparison.

Production of Two-Component Compositions:

Examples Z-1 to Z-7

[0230] For each composition, the ingredients specified in table 1 were mixed in the specified amounts (in parts by weight) of component 1 by means of a centrifugal mixer (SpeedMixer™ DAC 150, FlackTek Inc.) and stored with exclusion of moisture.

[0231] Similarly, the ingredients of component 2 specified in table 1 were processed and stored.

[0232] The two components of each composition were then processed by means of the centrifugal mixer in the specified mixing ratio (0.6/1 by weight) to give a homogeneous liquid and this was tested immediately as follows:

[0233] For the determination of pot life, an amount of 300 g of the freshly mixed composition was stirred in a 500 ml beaker with a spatula at intervals of 5 minutes until it felt as if the composition had thickened to such an extent that it would no longer have good workability.

[0234] For determination of the mechanical properties, the mixed composition was poured onto a PTFE-coated film to give a film of thickness 2 mm and stored under standard climatic conditions. After 1 day, a number of dumbbell-shaped test specimens having a length of 75 mm with a bar length of 30 mm and a bar width of 4 mm were punched out of the film and stored under standard climatic conditions for a further 6 days. Subsequently, these, as described in DIN EN 53504, at a strain rate of 2 mm/min, tensile strength (breaking force), elongation at break and modulus of elasticity at 0.5% to 1% elongation (MoE 0.5-1%) and at 0.5% to 5% elongation (MoE 0.5-5%) were determined. Similarly, a number of test specimens were punched out and stored for determination of tear resistance and were tested in accordance with DIN ISO 34 at a strain rate of 500 mm/min.

[0235] After 7 days under SCC, the appearance of all the films was rated visually. All films were black in color after curing, had absolutely zero tack with a silky matt surface, and were homogeneous and free of blisters. Such films were referred to as “nice”.

[0236] These results are reported in table 2.

[0237] Examples Z-1 to Z-3 and Z-5 to Z-6 are inventive examples in which the polymer containing silane groups has a silicon content according to the invention. Example Z-4 is a comparative example in which the polymer containing silane groups has a lower content than the silicon content of the invention. Example Z-7 is a comparative example in which the polymer containing silane groups has a higher content than the silicon content of the invention.

TABLE-US-00001 TABLE 1 Composition of examples Z-1 to Z-7. Example Z-4 Z-7 Z-1 Z-2 Z-3 (Ref.) Z-5 Z-6 (Ref.) Component 1: Polymer ST-1 ST-1 ST-2 ST-6 ST-3 ST-4 ST-5 62.2 56.0 62.2 62.2 62.2 62.2 62.2 Diisodecyl phthalate 1.4 7.6 1.4 1.4 1.4 1.4 1.4 Vinyltrimethoxysilane 2.4 2.4 2.4 2.4 2.4 2.4 2.4 1,2-Diamino- 27.4 27.4 27.4 27.4 27.4 27.4 27.4 cyclohexane.sup.1 Silquest ® A-1110.sup.2 2.3 2.3 2.3 2.3 2.3 2.3 2.3 Ancamine ® K54.sup.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 Stabilizer.sup.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 Carbon black 1.5 1.5 1.5 1.5 1.5 1.5 1.5 Dibutyltin dilaurate 0.1 0.1 0.1 0.1 0.1 0.1 0.1 Component 2: Bisphenol A 70.2 70.2 70.2 70.2 70.2 70.2 70.2 diglycidyl ether.sup.5 Hexanediol 23.4 23.4 23.4 23.4 23.4 23.4 23.4 diglycidyl ether.sup.6 Emulsifier 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Water 1.9 1.9 1.9 1.9 1.9 1.9 1.9 Fumed silica 2.4 2.4 2.4 2.4 2.4 2.4 2.4 Carbon black 1.5 1.5 1.5 1.5 1.5 1.5 1.5 Dibutyltin dilaurate 0.1 0.1 0.1 0.1 0.1 0.1 0.1 Mixing ratio.sup.7 0.6/1 0.6/1 0.6/1 0.6/1 0.6/1 0.6/1 0.6/1 .sup.1Dytek ® DCH-99 (from Invista) .sup.23-aminopropyltrimethoxysilane (from Momentive) .sup.32,4,6-tris(dimethylaminomethyl)phenol (from Evonik) .sup.4Irganox 1010 (from BASF) .sup.5Araldite ® GY 250 (from Huntsman) .sup.6Araldite ® DY-H (from Huntsman) .sup.7ratio of component 1/component 2 in parts by weight

TABLE-US-00002 TABLE 2 Properties of examples Z-1 to Z-7. Example Z-4 Z-7 Z-1 Z-2 Z-3 (Ref.) Z-5 Z-6 (Ref.) Silicon content 1.08 1.08 0.90 0.45 1.15 1.8 2.3 of the polymer containing silane groups [% by wt.] Diisocyanate in the MDI MDI TDI IPDI IPDI TDI TDI polymer Pot life [min] 30 30 30 30 30 30 30 Tensile strength 23.6 25.2 25.1 8.8 19.5 21.0 20.3 [MPa] Elongation at break 38% 27% 41% 35% 43% 58% 36% MoE 0.5-1% [MPa] 1127 1174 1059 80 735 892 877 MoE 0.5-5% [MPa] 353 385 386 57 263 307 317 Tear resistance 27.5 27.9 29.6 9.4 23.9 19.7 17.5 [N/mm] Appearance nice nice nice nice nice nice nice

[0238] In addition, the corrosion resistance or stability of a bond of two aluminum sheets (5754 alloy, AlMg3, bright) was tested with the composition from example Z-1 under saltwater stress. As a comparison, the same tests were conducted with a commercial two-component epoxy resin adhesive (2K epoxy adhesive) (=impact-resistant structural adhesive 07333, from 3M).

[0239] For this purpose, multiple bonded test specimens were produced by applying the freshly mixed adhesive between two bright, heptane-degreased aluminum sheets (AlMg3, 100×25×1 mm) in a layer thickness of 0.3 mm with an overlapping bond area of 10×25 mm. After a storage time of 7 days under standard climatic conditions, lap shear strength was determined to DIN EN 1465 at a strain rate of 10 mm/min. This value is reported in table 3 as 0 weeks (starting value).

[0240] Further test specimens of this kind were subjected to various cycles with saltwater stress, as described hereinafter. On the first day, the test specimens were placed into a salt solution (5% by weight of NaCl in deionized water) at room temperature for 15 min, then suspended and allowed to drip dry under standard climatic conditions for 95 min, followed by storage in a climate-controlled cabinet at 50° C./90% relative humidity for 22 h (=1 cycle). This was followed by a further 4 days with the same sequence, followed by 48 h in a climate-controlled cabinet at 50° C./90% relative humidity (weekend). This results in a storage time of 1 week with 5 cycles of saltwater stress. The test specimens were stored in this way for 2 weeks (10 cycles) or 4 weeks (20 cycles) or 6 weeks (30 cycles), and then the lap shear strength was determined in each case as described above. On completion of lap shear strength testing, the test specimens were assessed visually with regard to the fracture profile and the condition of the aluminum sheet under the bond (Appearance). “cf” means cohesive failure; “af” means adhesive failure. “No corrosion” means that the aluminum sheet has unchanged shine beneath the bond. “2-3 mm corrosion” means that the aluminum has a matt white color within a range of 2-3 mm from the edges beneath the bond. In the region not covered by the bond, all sheets have a spotty matt white appearance after saltwater stress.

[0241] These results are reported in table 3.

TABLE-US-00003 TABLE 3 Lap shear strength and appearance after saltwater stress of example Z-1 compared to a 2K epoxy adhesive (07333, from 3M) 2K epoxy adhesive Example Z-1 (Ref.) 0 weeks 13.9 MPa 10.5 MPa  25% cf/75% af, 100% af, no corrosion 2-3 mm corrosion 2 weeks (10 cycles) 13.8 MPa 7.9 MPa 25% cf/75% af, 100% af, no corrosion 2-3 mm corrosion 4 weeks (20 cycles) 12.3 MPa 6.3 MPa 25% cf/75% af, 100% af, 0-1 mm corrosion 2-3 mm corrosion 6 weeks (30 cycles) 12.1 MPa 5.2 MPa 25% cf/75% af, 100% af, 2-3 mm corrosion 2-3 mm corrosion

[0242] Adhesion on dry and wet concrete and bitumen was also determined for the composition from example Z-1. For this purpose, 3 concrete slabs (500×500×40 mm) and 3 bitumen slabs (about 300×200×30 mm) were provided. Two slabs were each coated in the dry state with the freshly mixed composition in a layer thickness of about 3 to 4 mm. The third slab was placed into deionized water for 24 h and then, in the wet state with residues of standing water on the surface, likewise coated with the freshly mixed composition in a layer thickness of about 3 to 4 mm. Several acetone-cleaned steel cylinders having a diameter of 20 mm were applied to each of the freshly coated slabs, such that a bond was formed between the steel cylinders and the composition (coating). After a storage time of the coated slabs of 7 days under standard climatic conditions, the bond strength value was determined in each case on one of the two dry slabs and on the wet slab. The further slab coated in the dry state was placed into deionized water for 7 days, the surface was dried, and only then was the bond strength value determined. The value for bond strength was determined in each case by pulling on the bonded steel cylinder according to DIN EN 4624 at a testing speed of 2 mm/min until it broke away from the slab.

[0243] These results are reported in table 4.

TABLE-US-00004 TABLE 4 Bond strength results for the composition from example Z-1 on concrete and bitumen dry + water dry wet for 7 d Concrete bond strength [MPa] 6.54 6.62 6.43 Fracture profile 100% 100% 100% substrate substrate substrate fracture fracture fracture Bitumen bond strength [MPa] 2.35 2.15 2.45 Fracture profile 100% 100% 100% substrate substrate substrate fracture fracture fracture