ACCELERATOR FOR CURING EPOXY RESINS COMPRISING ALKYLATED AMINES

Abstract

A composition containing calcium nitrate, at least one epoxy resin and at least one amine of formula (I). The composition allows the manufacture of low-emission epoxy-resin coatings that have good workability and that cure particularly rapidly in cold and damp conditions, without blushing-induced surface defects, thus achieving coatings of in particular high mechanical quality, with a minimal tendency to yellowing.

Claims

1. A composition comprising calcium nitrate, at least one epoxy resin and at least one amine of the formula (I),
(H.sub.2N).sub.m-A-(NH—Y).sub.n  (I) where m is 0 or 1, n is 1 or 2 and (m+n) is 2, A is an alkylene radical that optionally contains nitrogen atoms or cyclic or aromatic components and has 2 to 10 carbon atoms, and Y is an alkyl, cycloalkyl or aralkyl radical having 1 to 20 carbon atoms.

2. The composition as claimed in claim 1, wherein calcium nitrate is in the form of an aqueous solution.

3. The composition as claimed in claim 1, wherein 0.1 to 20 parts by weight of calcium is present per 100 parts by weight of all amines having primary and/or secondary amino groups present.

4. The composition as claimed in claim 1, wherein A is 1,2-ethylene, 1,2-propylene, 1,3-cyclohexylenebis(methylene) or 1,3-phenylenebis(methylene).

5. The composition as claimed in claim 1, wherein Y is a radical selected from 2-ethylhexyl, 2-phenylethyl, benzyl, 1-naphthylmethyl and cyclohexylmethyl.

6. The composition as claimed in claim 1, wherein m and n are each 1.

7. The composition as claimed in claim 1, wherein the amine of the formula (I) is N-benzylethane-1,2-diamine or N-benzylpropane-1,2-diamine.

8. The composition as claimed in claim 1, wherein 0.1 to 1.2 mol of amine hydrogens from amines of the formula (I) is present per mole of epoxy groups.

9. The composition as claimed in claim 1, wherein it additionally comprises at least one further constituent selected from further accelerators, reactive diluents, further amines, thinners and fillers.

10. The composition as claimed in claim 1, wherein it comprises 2,4,6-tris(dimethylaminomethyl)phenol.

11. The composition as claimed in claim 1, wherein it comprises at least one further amine selected from the group consisting of 2,2(4),4-trimethylhexane-1,6-diamine, 1,2-, 1,3- or 1,4-diaminocyclohexane, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, bis(4-aminocyclohexyl)methane, 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane, 2(4)-methyl-1,3-diaminocyclohexane, 1,3-bis(aminomethyl)benzene, polyoxypropylenediamines having an average molecular weight M.sub.n in the range from 200 to 500 g/mol, 3-(3-(dimethylamino)propylamino)propylamine, bis(6-aminohexyl)amine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, dipropylenetriamine, N-(2-aminoethyl)propane-1,3-diamine, N,N′-bis(3-aminopropyl)ethylenediamine, adducts of these or further polyamines with mono- or diepoxides, and Mannich bases.

12. The composition as claimed in claim 1, wherein it comprises at least one thinner selected from the group consisting of benzyl alcohol, styrenized phenol, ethoxylated phenol, aromatic hydrocarbon resins containing phenol groups, diisopropylnaphthalene and cardanol.

13. A method of coating, comprising the steps of (i) mixing the components of the composition as claimed in claim 1, (ii) applying the mixed composition to a substrate within the pot life, followed by the curing of the mixed composition.

14. A method of bonding, comprising the steps of (i) mixing the components of the composition as claimed in claim 1, (ii) applying the mixed composition within the pot life, either to at least one of the substrates to be bonded and joining the substrates to form a bond within the open time, or into a cavity or gap between two or more substrates and optionally inserting an anchor into the cavity or gap within the open time, followed by the curing of the mixed composition.

15. An article obtained from the method as claimed in claim 13.

Description

EXAMPLES

[0151] 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.

[0152] “ANEW” stands for amine hydrogen equivalent weight.

[0153] “EEW” stands for epoxy equivalent weight.

[0154] “Standard climatic conditions” refer to a temperature of 23±1° C. and a relative air humidity of 50±5%.

Description of the Measurement Methods:

[0155] Viscosity was measured on a thermostated Rheotec RC30 cone-plate viscometer (cone diameter 50 mm, cone angle 1°, cone tip-plate distance 0.05 mm, shear rate 10 s.sup.−1).

[0156] Amine value was determined by means of titration (with 0.1N HClO.sub.4 in acetic acid versus crystal violet).

Substances and Abbreviations Used:

[0157] Sikafloor®-264N (A) Sikafloor®-264N component A (RAL 5005), filled pigmented resin component of an epoxy resin floor coating, EEW 450 g/eq (from Sika) [0158] B-EDA N-benzylethane-1,2-diamine, prepared as described below, AHEW 50.1 g/eq [0159] B-PDA N-benzylpropane-1,2-diamine, prepared as described below, AHEW 54.8 g/eq [0160] TETA triethylenetetramine, AHEW about 28 g/eq (technical grade, from Huntsman) [0161] Adduct-1 adduct of propylene-1,2-diamine and technical grade o-cresyl glycidyl ether, prepared as described below, AHEW 90 g/eq [0162] Jeffamine® D-230 polyoxypropylenediamine with average molecular weight about 240 g/mol, AHEW 60 g/eq (from Huntsman) [0163] Ca nitrate solution 50% by weight of calcium nitrate tetrahydrate in water [0164] Ancamine® K54 2,4,6-tris(dimethylaminomethyl)phenol (from Air Products)

N-Benzylethane-1,2-diamine (B-EDA)

[0165] A round-bottom flask was initially charged with 180.3 g (3 mol) of ethylene-1,2-diamine under a nitrogen atmosphere at room temperature. With good stirring, a solution of 106.0 g (1 mol) of benzaldehyde in 1200 ml of isopropanol was slowly added dropwise, and the mixture was stirred for 2 hours. The reaction mixture was then hydrogenated in a continuous hydrogenation apparatus with a Pd/C fixed bed catalyst at a hydrogen pressure of 80 bar, a temperature of 80° C. and a flow rate of 5 ml/min. To monitor the reaction, IR spectroscopy was used to check whether the imine band at about 1665 cm.sup.−1 had disappeared. Thereafter, the hydrogenated solution was concentrated on a rotary evaporator at 65° C., removing unreacted ethylene-1,2-diamine, water and isopropanol. The reaction mixture thus obtained was a clear, pale yellowish liquid having an amine value of 678 mg KOH/g. 50 g of this were distilled at 80° C. under reduced pressure, with collection of 31.3 g of distillate at a vapor temperature of 60 to 65° C. and 0.06 mbar. What was obtained was a colorless liquid having a viscosity of 8.3 m.Math.Pas at 20° C., an amine value of 750 mg KOH/g and a purity, determined by GC, of >97%.

N-Benzylpropane-1,2-diamine (B-PDA)

[0166] A round-bottom flask was initially charged with 444.8 g (6 mol) of propane-1,2-diamine under a nitrogen atmosphere at room temperature. With good stirring, a solution of 212.2 g (2 mol) of benzaldehyde in 1′500 ml of isopropanol was slowly added dropwise, and the mixture was stirred for 2 hours. The reaction mixture was then hydrogenated in a continuous hydrogenation apparatus with a Pd/C fixed bed catalyst at a hydrogen pressure of 90 bar, a temperature of 85° C. and a flow rate of 5 ml/min. To monitor the reaction, IR spectroscopy was used to check whether the imine band at about 1665 cm.sup.−1 had disappeared. Thereafter, the hydrogenated solution was concentrated on a rotary evaporator at 65° C., removing unreacted propane-1,2-diamine, isopropanol and water. A clear, pale yellowish liquid was obtained. 300 g of this were distilled at 80° C. under reduced pressure, with collection of 237.5 g of distillate at a vapor temperature of 60 to 65° C. and 0.08 mbar. A colorless liquid having an amine value of 682 mg KOH/g was obtained, which, by .sup.1H NMR, was a mixture of N.sup.1-benzylpropane-1,2-diamine and N.sup.2-benzylpropane-1,2-diamine in a ratio of about 2/1 and had a GC purity of >97%.

Adduct-1:

[0167] An initial charge of 4.15 kg of propane-1,2-diamine under a nitrogen atmosphere was heated to 70° C. and then, with good stirring, 2.93 kg of Araldite® DY-K (o-cresyl glycidyl ether, technical grade, from Huntsman) was added gradually, with the temperature of the reaction mixture from 70 to 80° C. After 1 hour at 80° C., the reaction mixture was cooled down and the volatile constituents were removed by distillation by means of a thin-film evaporator (0.5-1 mbar, jacket temperature 115° C.).

Production of Epoxy Resin Compositions:

Examples 1 to 17

[0168] For each example, the ingredients of the curing agent component indicated in tables 1 to 3 were mixed in the indicated amounts (in parts by weight) by means of a centrifugal mixer (SpeedMixer™ DAC 150, FlackTek Inc.) and stored with the exclusion of moisture.

[0169] The resin component used was Sikafloor®-264N comp. A (blue) (from Sika) in the amount specified in tables 1 to 3 (in parts by weight).

[0170] The two components of each composition were then processed by means of the centrifugal mixer to give a homogeneous liquid and this was tested immediately as follows:

[0171] 10 minutes after mixing, the viscosity was measured at 20° C. (“Viscosity (10′)”). For the determination of Shore D hardness to DIN 53505, two cylindrical test specimens (diameter 20 mm, thickness 5 mm) in each case were produced. One was stored under standard climatic conditions and hardness was measured after 1 day and after 2 days (1 d SCC and 2d SCC); the other was stored at 8° C. and 80% relative humidity and hardness was measured after 1 day and after 2 days in the cold state (1d 8°/80% and 2d 8°/80%).

[0172] A first film coating was applied to a glass plate in a layer thickness of 500 μm, and this was stored/cured under standard climatic conditions. König hardness (König pendulum hardness, measured according to DIN EN ISO 1522) was determined on this film after 1 day (“König hardness (1 d SCC)”), after 2 days (“König hardness (2d SCC)”), after 4 days (“König hardness (4d SCC)”), after 7 days (“König hardness (7d SCC)”) and after 14 days (“König hardness (14d SCC)”). After 14 days, the appearance of the film was assessed (designated

[0173] “Appearance (SCC)” in the table). A film was described as “nice” if it had a glossy and nontacky surface with no structure. “Structure” refers to any kind of marking or pattern on the surface. A film with a nontacky surface without structure and with reduced gloss was described as “matt”.

[0174] A second film coating was applied to a glass plate in a layer thickness of 500 μm and immediately after application this was stored/cured for 7 days at 8° C. and 80% relative humidity and then for 2 weeks under standard climatic conditions.

[0175] 24 hours after application, a polypropylene bottletop beneath which a damp sponge had been positioned was placed onto the film. After a further 24 hours, the sponge and the bottletop were removed and positioned at a new point on the film, from which it was in turn removed and repositioned after 24 hours, and this was done a total of 4 times. The appearance of this film was then assessed (designated “Appearance (8°/80%)” in the tables) in the same way as described for Appearance (SCC). Also reported in each case here was the number and kind of visible marks that had formed in the film as a result of the damp sponge or the bottletop on top. The number of white-colored spots was reported as “blushing”. The intensity of any ring-shaped impression formed by sinking of the first bottletop applied 24 h after application was reported as “ring”. Such a ring-shaped impression indicates that the coating was not ready to be walked upon. The König hardness was again determined on the films thus cured, in each case after 7 days at 8° C. and 80% relative humidity (“König hardness (7d 8°/80%)”) and then after a further 2 days under SCC (“König hardness (+2d SCC)”), 7 days under SCC (“König hardness (+7d SCC)”), and 14 d under SCC (“König hardness (+14d SCC)”).

[0176] Also determined as a measure of yellowing was the change in color after stressing in a weathering tester. For this, a further film was applied to a glass plate in a layer thickness of 500 μm and this was stored/cured under standard climatic conditions for 2 weeks and then stressed for 72 hours (Q-Sun (72h)) at a temperature of 65° C. in a model Q-Sun Xenon Xe-1 weathering tester having a Q-SUN Daylight-Q optical filter and a xenon lamp having a light intensity of 0.51 W/m.sup.2 at 340 nm. The color difference ΔE of the stressed film versus the corresponding unstressed film was then determined using an NH310 colorimeter from Shenzen 3NH Technology Co. LTD equipped with silicon photoelectric diode detector, light source A, color space measurement interface CIE L*a*b*C*H*. ΔE values up to 5 represent slight yellowing.

[0177] The results are reported in tables 1 to 3.

[0178] The examples labeled “(Ref.)” are comparative examples.

TABLE-US-00001 TABLE 1 Composition and properties of examples 1 to 6. 1 3 4 6 Example (Ref.) 2 (Ref.) (Ref.) 5 (Ref.) Resin comp.: Sikafloor ®-264N (A) 450.0 450.0 450.0 450.0 450.0 450.0 Curing agent comp.: B-EDA 50.1 50.1 50.1 50.1 50.1 50.1 Ca nitrate solution — 2.0 — — 2.0 — Salicylic acid.sup.1 — — 2.0 — — 2.0 Ancamine ® K54 — — — 2.0 2.0 2.0 Viscosity (10′) [Pa .Math. s] 2.2 2.6 2.6 2.2 2.4 2.5 Shore D (1 d SCC) 74 78 77 80 78 78 (2 d SCC) 77 80 80 80 80 80 Shore D (1 d 8°/80%) 29 61 51 45 62 53 (2 d 8°/80%) 68 75 74 72 64 74 König h. [s] (1 d SCC) 63 78 67 97 104 95 [s] (2 d SCC) 88 104 104 118 140 132 (4 d SCC) 99 120 115 130 147 139 (7 d SCC) 115 121 131 126 151 157 (14 d SCC) 118 126 140 137 156 162 Appearance (SCC) nice nice nice nice nice nice Q-SUN (72 h) ΔE 2.9 2.7 5.4 3.8 4.7 6.4 König h. [s] (7 d 17 21 20 25 24 27 8°/80%) [s] (+2 d SCC) 35 38 42 55 57 56 (+7 d SCC) 52 53 59 70 76 76 (+14 d SCC) 67 67 78 89 93 95 Appearance (8°/80%) nice nice matt matt nice matt Blushing 3 3 3 3 3 3 Ring average none strong slight none slight .sup.1dissolved in B-EDA

TABLE-US-00002 TABLE 2 Composition and properties of examples 7 to 12. 7 10 12 Example (Ref.) 8 9 (Ref.) 11 (Ref.) Resin comp.: Sikafloor ®-264N (A) 450.0 450.0 450.0 450.0 450.0 450.0 Curing agent comp.: B-EDA 50.1 50.1 50.1 50.1 42.6 42.6 TETA — — — — 4.2 4.2 Benzyl alcohol 10.0 10.0 10.0 10.0 10.0 10.0 Ca nitrate solution — 2.0 2.0 — 2.0 — Ancamine ® K54 — — 2.0 2.0 2.0 2.0 Viscosity (10′) [Pa .Math. s] 1.4 1.9 1.5 1.4 1.7 1.4 Shore D (1 d SCC) 48 52 53 64 60 70 (2 d SCC) 64 64 72 73 74 76 Shore D (1 d 8°/80%) 8 33 23 13 43 32 (2 d 8°/80%) 57 69 64 70 73 72 König h. [s] (1 d SCC) 17 34 48 41 63 62 [s] (2 d SCC) 46 56 78 81 91 90 (4 d SCC) 45 73 98 192 105 105 (7 d SCC) 73 85 104 109 122 113 (14 d SCC) 92 104 113 113 136 125 Appearance (SCC) nice nice nice nice nice nice Q-SUN (72 h) ΔE 2.7 4.0 4.7 3.4 4.2 2.1 König h. [s] (7 d 8°/80% 7 10 13 10 17 15 [s] (+2 d SCC) 14 20 21 18 39 42 (+7 d SCC) 14 24 39 35 65 67 (+14 d SCC) 35 43 60 60 87 85 Appearance (8°/80%) nice nice nice nice nice nice Blushing 1 0 1 1 1 1 Ring average none none slight none none

TABLE-US-00003 TABLE 3 Composition and properties of examples 13 to 17. 14 17 Example 13 (Ref.) 15 16 (Ref.) Resin comp.: Sikafloor ®-264N (A) 450.0 450.0 450.0 450.0 450.0 Curing agent comp.: B-EDA 32.6 — — — — B-PDA — 54.8 54.8 54.8 54.8 Adduct-1 13.5 — — — — Jeffamine ® D-230 12.0 — — — — Ca nitrate solution 2.0 — 2.0 2.0 — Ancamine ® K54 2.0 — — 2.0 2.0 Viscosity (10′) [Pa .Math. s] 2.9 1.9 1.9 1.7 1.3 Shore D (1 d SCC) 71 53 73 70 64 (2 d SCC) 76 74 79 77 76 Shore D (1 d 8°/80%) 5 n.m. n.m. n.m. n.m. (2 d 8°/80%) 58 29 60 62 48 König h. [s] (1 d SCC) 68 85 94 104 108 [s] (2 d SCC) 113 144 154 184 175 (4 d SCC) 154 164 175 189 189 (7 d SCC) 168 188 202 204 200 (14 d SCC) 193 193 204 208 204 Appearance (SCC) nice nice nice nice nice Q-SUN (72 h) ΔE 5.9 1.9 3.5 4.6 4.1 König h. [s] (7 d 8°/80% 23 53 62 69 67 [s] (+2 d SCC) 67 134 147 148 146 (+7 d SCC) 80 140 157 168 165 (+14 d SCC) 84 140 158 169 165 Appearance (8°/80%) nice nice nice nice matt Blushing 1 1 1 1 2 Ring slight strong slight slight strong “n.m.” means “not measurable” (too soft)