CATALYST COMPOSITION FOR CURING RESINS CONTAINING EPOXY GROUPS

Abstract

The present invention relates to a catalyst composition for curing resins containing epoxy groups, in particular epoxy/polyurethane hybrid resins, the catalyst composition containing an imidazolium salt, in addition to a base, as well as a method for curing such resins in the presence of the catalyst composition, to the use of the catalyst composition for curing resins containing epoxy groups, to resin systems comprising a resin containing epoxy groups and the catalyst composition, and to a dosing system that comprises the resin and the catalyst composition.

Claims

1. A catalyst composition for curing a resin containing epoxy groups comprising: (i) at least one ionic compound of formula (I) ##STR00003## where X is any anion; is a single or double bond; n is 1, 2 or 3; and R groups are: R.sub.1 and R.sub.3 are in each case selected independently of one another from the group consisting of a linear or branched alkyl having 1 to 20 carbon atoms; a linear or branched alkenyl having 3 to 20 carbon atoms; and a substituted or unsubstituted aryl having 5 to 20 carbon atoms; R.sub.2 is hydrogen; R.sub.4 and R.sub.5 are in each case selected independently of one another from the group consisting of hydrogen, a linear or branched alkyl having 1 to 20 carbon atoms; a linear or branched alkenyl having 3 to 20 carbon atoms; a linear or branched alkoxy having 1 to 20 carbon atoms; and a substituted or unsubstituted aryl having 5 to 10 carbon atoms; or R.sub.1 and R.sub.5 and/or R.sub.3 and R.sub.4 or R.sub.4 and R.sub.5, together with the carbon or nitrogen atoms to which they are bonded, form a 5-6 membered substituted or unsubstituted cycloalkyl-, cycloheteroalkyl-, aryl- or heteroaryl ring, wherein the cycloheteroalkyl- or heteroaryl ring contains 1 to 3 heteroatoms selected from O, N and S; and (ii) at least one base.

2. The catalyst composition according to claim 1, wherein the at least one base is a non-ionic base which contains nitrogen, of formula (II) and/or of formula (III),
NR.sub.6R.sub.7R.sub.8  (II)
N(═R.sub.9)R.sub.10  (III) wherein R.sub.6 to R.sub.8 and R.sub.10 are in each case selected independently of one another from the group consisting of substituted or unsubstituted, linear or branched alkyl having 1 to 20 carbon atoms, substituted or unsubstituted, linear or branched alkenyl having 3 to 20 carbon atoms and substituted or unsubstituted aryl having 5 to 20 carbon atoms, or at least two of R.sub.6 to R.sub.8, together with the nitrogen atom to which they are bonded, form a 5- to 10-membered, heteroalicyclic ring or heteroaryl ring which optionally contains further nitrogen atoms, and R.sub.9 is a substituted or unsubstituted, linear or branched alkylenyl having 3 to 20 carbon atoms or R.sub.9 and R.sub.10, together with the nitrogen atom to which they are bonded, form a 5- to 10-membered, heteroalicyclic ring or heteroaryl ring which optionally contains further nitrogen atoms.

3. The catalyst composition according to claim 1, wherein the at least one base is a non-ionic base which contains nitrogen, which is selected from the group consisting of 1-methylimidazole, 2,4-ethylmethylimidazole, 1,4-diazabicyclo[2.2.2]octane (DABCO), 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) and mixtures thereof.

4. The catalyst composition according to claim 1, wherein the anion X is selected from the group consisting of dicyandiamide anion, F.sup.−, Cl.sup.−, Br.sup.−, I.sup.−, OH.sup.−, HSO.sub.3.sup.−, SO.sub.3.sup.2-, SO.sub.4.sup.2-, NO.sub.2.sup.−, NO.sub.3.sup.−, PO.sub.4.sup.3-, BF.sub.4.sup.−, PF.sub.6.sup.−, ClO.sub.4.sup.−, acetate, citrate, formate, glutarate, lactate, malate, malonate, oxalate, pyruvate, tartrate, cyanamide, SCN— and P(OEt).sub.2O.sub.2.

5. The catalyst composition according to claim 4, wherein the anion X is selected from the group consisting of Cl.sup.−, Br.sup.−, I.sup.−, SO.sub.4.sup.2-, NO.sub.2.sup.−, NO.sub.3.sup.−, PO.sub.4.sup.3-, BF.sub.4.sup.−, SbF.sub.6.sup.−, PF.sub.6.sup.−, ClO.sub.4.sup.−, acetate, cyanamide, SCN.sup.− and P(OEt).sub.2O.sub.2.sup.−.

6. The catalyst composition according to claim 1, having a weight ratio of the at least one ionic compound of formula (I) to the at least one base in a range of from 10:1 to 1:10.

7. The catalyst composition according to claim 1, wherein the catalyst composition further comprises a solvent selected from the group consisting of petroleum, benzene, toluene, xylene, ethylbenzene and mixtures thereof.

8. The catalyst composition according to claim 1, wherein the at least one ionic compound of formula (I) comprises a 1,3-substituted imidazolium compound, where R.sub.1 and R.sub.3 are selected from unsubstituted C.sub.1-4-alkyl residues, unsubstituted or substituted C.sub.6-aryl residues and mixtures thereof; and R.sub.2, R.sub.4 and R.sub.5 are hydrogen.

9. The catalyst composition according to claim 8, wherein R.sub.1 and R.sub.3 are selected from methyl residues; ethyl residues; substituted phenyl residues having one or more C.sub.1-4 alkyl substitutes; and mixtures thereof.

10. The catalyst composition according to claim 8, wherein the at least one base is a non-ionic base which contains nitrogen, and is selected from the group consisting of 1-alkyl-imidazoles, 2,4-dialkyl imidazoles, amidine derivatives, bicyclic tertiary amines and mixtures thereof.

11. The catalyst composition according to claim 10, wherein the at least one base is a non-ionic base which contains nitrogen, which is selected from the group consisting of 1-methylimidazole; 2,4-ethylmethylimidazole; 1,4-diazabicyclo[2.2.2]octane (DABCO); 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU); and mixtures thereof.

12. A method for curing a resin containing epoxy groups comprising a step of contacting the resin containing epoxy groups with the catalyst composition according to claim 1 under conditions which enable curing.

13. The method according to claim 12, wherein the resin containing epoxy groups is an epoxy/polyurethane hybrid resin or an epoxy/isocyanate resin, and the catalyst composition is selected such that the resins containing epoxy groups cure in not less than 1 minute and not more than 30 minutes.

14. The method according to claim 12, wherein 0.01 to 10 wt.-% of the catalyst composition is used, relative to the overall quantity of resin containing epoxy groups.

15. A polymer composition, containing at least one resin containing epoxy groups and a catalyst composition according to claim 1.

16. The polymer composition according to claim 15, wherein the catalyst composition is selected such that pot life ranges from greater than 90 seconds to approximately 6 minutes.

17. A dosing system, wherein the dosing system comprises: (i) a resin containing epoxy groups; and (ii) the catalyst composition according to claim 1; wherein the catalyst and the resin are contained in separate containers; the dosing system optionally comprising a dosing device.

Description

EXAMPLES

Example 1

[0094] Firstly, DER331 (Dow Chemical, liquid epoxy resin of epichlorohydrin and bisphenol A) and PPG2000 (Bayer, polypropylene glycol with Mw 2000) are mixed for 60 seconds (s) at 2000 rpm in the vacuum in the speedmixer. Once the reaction mixture has cooled to room temperature (RT), the imidazolium salt is added and mixing takes place again for 30 s at 2000 rpm in the speedmixer in the vacuum. After cooling again to RT, the non-ionic base is added and then mixing takes place again for 30 s at 2000 rpm. The imidazolium salt and the base are used in a weight ratio of 1:1. The concentrations indicated in the table relate to the sum of both catalysts relative to the overall weight of the reaction mixture. Directly thereafter, Desmodur Vk 5 (Bayer, mixture of monomeric polyisocyanates) is added, and then mixing takes place again for 30 s at 2000 rpm in the vacuum. The obtained resin composition contains 55% epoxy, 5% polyol and 45% isocyanate.

[0095] To determine the mechanical properties, the reaction mixture is poured into an upright mold and gelatinized at RT. Thereafter, the mixture is cured in two stages (1 h at 90° C. and 1 h at 150° C.). After cooling, the testpieces required for the mechanical tests are cut out of the plate obtained in this way.

[0096] To determine the pot life, the reaction mixture is stored at RT and the gel time is determined manually. The results of the test are summarized in tables 1 and 2. The mechanical statistical values were ascertained in a 200 g batch: Tensile test according to EN ISO 527; 3-point bending according to EN ISO 178; fracture toughness according to IOS 13586; Tg by means of DMTA. The pot life (open time) was determined at RT in a 10 g batch.

TABLE-US-00001 TABLE 1 Pot life 1- 2-ethyl-4- methylimidazole methylimidazole DABCO DBU 1H imidazolium, 1- 1%-5 min 1%-3 min 0.2%-3 min 0.4%-2 min ethyl-3-methyl acetate 1H imidazolium, 1- 2%-<10 min 0.3%-5 min 2%-5 min ethyl-3-methyl thiocyanate 1H imidazolium, 1- 0.16%-6 min ethyl-3-methyl salt with cyanocyanamide 1-ethyl-3- 0.2%-<10 min 1.4%-5 min ethylimidazolium diethyl phosphate no imidazolium 1%-60 min 1% >18 h 1%-<5 sec 1%->18 h salt

TABLE-US-00002 TABLE 2 Mechanical properties 1-methyl 2-ethyl-4-methyl imidazole imidazole DABCO DBU 1H imidazolium, No data No data No data Plate with 0.4% 1-ethyl-3-methyl catalyst acetate EN ISO 527/2, 3 Emod: 3070 MPa max: 18 Elongation at break: 0.5 3-point bending Emod: 3160 Fmax: 53 Upsetting: 1.6 K1c: 0.6 1H imidazolium, Plate with 2% Plate with 0.2% Plate with 1% 1-ethyl-3-methyl catalyst catalyst catalyst thiocyanate EN ISO 527/2, 3 EN ISO 527/2, 3 EN ISO 527/2, 3 Emod: 2980 MPa Emod: — Emod: 3050 MPa max: 80.1 MPa max: — max: 65.4 Elongation at Elongation at Elongation at break: 1.77 break: — break: 2.46 3-point bending 3-point bending 3-point bending Emod: 2990 Emod: 3090 Emod: 2951 Fmax: 129.7 Fmax: 69.1 Fmax: 138.3 Upsetting: 5.2 Upsetting: 2.33 Upsetting: 6.99 K1c: 1.22 K1c: 0.57 K1c: 1.75 Tg G″: 163 Tg G″: Tg G″: 104/158 Tg tan delta: 186 Tg tan delta: Tg tan delta: 178 1H imidazolium, No data 1-ethyl-3-methyl salt with cyanocyanamide 1-ethyl-3- Plate with 0.2% Plate with 0.2% ethylimidazolium catalyst catalyst diethyl EN ISO 527/2, 3 EN ISO 527/2, 3 phosphate Emod: 3126 MPa Emod: 3030 MPa max: 36.7 max: 43 Elongation at Elongation at break: 36.7 break: 1.2 3-point bending 3-point bending Emod: 3090 Emod: 2980 Fmax: 69.1 Fmax: 144 Upsetting: 2.33 Upsetting: 7.6 K1c: 0.57 K1c: 1.6 Tg G″: 64 Tg G″: 162 Tg tan delta: 123 Tg tan delta: 183 no imidazolium Plate with Plate with 1% Mixture with 1% Plate with 1% salt 1% catalyst catalyst catalyst cures too catalyst EN ISO EN ISO 527/2, 3 quickly to produce EN ISO 527/2, 3 527/2, 3 Emod: 2797 MPa a testpiece Emod: 2631 MPa Emod:. 2808 MPa max: 87.6 max: 85.7 max: Elongation at Elongation at 90.1 break: 4.80 break: 6.43 Elongation 3-point bending 3-point bending at break: Emod: 2728 Emod: 2461 6.07 Fmax: 130.2 Fmax: 120.2 3-point Upsetting: 7.06 Upsetting: 6.83 bending K1c: 2.41 K1c: 3.09 Emod: 2776 Tg G″: 67/160 Tg G″: 161 Fmax: Tg tan delta: Tg tan delta: 176 130.1 69/178 Upsetting: 6.88 K1c: 2.17 Tg G″: 163 Tg tan delta: 179