Accelerator Composition for the Cure of Epoxy Resins with Aromatic Amines

Abstract

The disclosure relates to an accelerator composition for the cure of epoxy resins with aromatic amines comprising: (a) a metal complex with carboxylate ligands; and (b) a boron trifluoride amine complex or a boron trifluoride phenol complex. The disclosure also relates to a curing composition for the cure of epoxy resin comprising: (i) an aromatic amine as curing agent; and (ii) the above accelerator composition or, alternatively, a mixture of (1) a metal complex with carboxylate ligands and (2) neat boron trifluoride or boron trifluoride etherate for in-situ formation of a boron trifluoride amine complex with the aromatic amine . Additionally, the disclosure relates to the use of such compositions and to a cured resin product obtainable from the use of such compositions.

Claims

1. An accelerator composition for the cure of epoxy resins with aromatic amines comprising (a) a metal complex with carboxylate ligands; and (b) a boron trifluoride amine complex or a boron trifluoride phenol complex.

2. The accelerator composition of claim 1, wherein the metal cation of the metal complex with carboxylate ligands is selected from zinc, tin and chromium.

3. The accelerator composition of claim 1 or 2, wherein the carboxylate ligands are selected from octoates, neodecanoates and naphthenates.

4. The accelerator composition according to any of the preceding claims, wherein the amine of the boron trifluoride amine complex is selected from ethylamine, monoisopropylamine, N-methylcyclohexylamine, piperidine and 2,4-dimethylaniline.

5. The accelerator composition of any of the preceding claims, wherein the phenol of the boron trifluoride phenol complex is selected from phenol, 2-methylphenol, 3-methylphenol and 4-methylphenol.

6. The accelerator composition according to any of the preceding claims, wherein the stoichiometric ratio of (a):(b) is in the range from 1:50 to 50:1.

7. The accelerator composition according to claim 6, wherein the stoichiometric ratio of (a):(b) is in the range from 1:10 to 10:1.

8. The accelerator composition according to claim 7, wherein the stoichiometric ratio of (a):(b) is in the range from 1:3 to 3:1.

9. A curing composition for the cure of epoxy resin comprising (i) an aromatic amine as curing agent; and (ii) an accelerator composition according to any the preceding claims or, alternatively, a mixture of (1) a metal complex with carboxylate ligands and (2) neat boron trifluoride or boron trifluoride etherate for in-situ formation of a boron trifluoride amine complex with the aromatic amine.

10. A curable epoxy composition comprising: (i) an epoxy resin; (ii) an aromatic amine as a curing agent; and (iii) an accelerator composition according to any one of claims 1 to 8.

11. The curable epoxy composition of claim 10, wherein the amount of the accelerator composition added with respect to the epoxy resin is in the range from 0.01 to 15 parts of accelerator composition per 100 parts of epoxy resin.

12. A method of preparing a curable epoxy composition comprising mixing (i) an epoxy resin; (ii) an aromatic amine; and (iii) the accelerator composition according to any one of claims 1 to 8 or, alternatively, a mixture of (1) a metal complex with carboxylate ligands and (2) neat boron trifluoride or boron trifluoride etherate for in-situ formation of a boron trifluoride amine complex with the aromatic amine.

13. A method of producing a cured resin product comprising a step of curing the curable epoxy composition of claim 10 for a time and temperature sufficient to substantially cure the curable epoxy composition.

14. A curable resin product obtained by the method of claim 13.

15. Use of an accelerator composition according to any of claims 1 to 8 for curing an epoxy resin with an aromatic amine or of a curing composition according to claim 9 for curing an epoxy resin.

16. The use according to claim 15, wherein the aromatic amine is selected from diethyltoluene diamine, 4,4′-methylenebis(2-ethylaniline), 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylsulfone, 3,3′-diaminophenylsulfone, 1,2-, 1,3- and 1,4-benzenediamine, bis(4-aminophenyl)methane, 1,3-xylenediamine, 1,2-diamino-3,5-dimethylbenzene, 4,4′-diamino-3,3′-dimethylbiphenyl, 4,4′-methylene-bis(2,6-dimethylaniline), 1,3-bis(m-aminophenoxy)benzene, 9,9-bis(4-aminophenyl)fluorene, 3,3′-diaminodiphenylsulfone, 4,4′-diaminodiphenylsulfide, 1,4-bis(p-aminophenoxy)benzene, 1,3-propanediol-bis(4-aminobenzoate and mixtures thereof.

17. The use according to claim 15 or 16, wherein the amount of the accelerator composition added in respect to the epoxy resin is in the range from 0.01 to 15 parts per 100 parts of resin.

18. A cured resin product obtainable from the use according to any of claims 15 to 17.

Description

EXAMPLES

[0055] A standard BADGE (bisphenol A diglycidyl ether) resin (Araldite® GY 250 available from Huntsman Corp. or an affiliate thereof) was cured isothermally at 130° C. followed by Dynamic Scanning calorimetry (DSC) with diethyltoluene diamine (Lonzacure® DETDA 80 from Lonza) in an equimolar ratio (100 parts by weight Araldite® GY 250, 24.1 parts by weight Lonzacure® DETDA 80). Zinc octoate (Alfa Aesar), boron trifluoride ethylamine complex (Sigma Aldrich) and various mixtures according to the present disclosure were investigated as the accelerator species.

TABLE-US-00001 TABLE 1 Screening of synergistic acceleration effect of metal carboxylates in combination with boron trifluoride ethylamine complex for the cure of 100 phr Araldite ® GY 250 with 24.1 phr Lonzacure ® DETDA 80 (0.135 mol) followedby DSC (catalyst loading 0.016 mol, with a molar ratio metal carboxylate/boron trifluoride ethylamine complex of 0.75). Tg onset/Tg Time to 95% midpoint Tg onset/Tg conversion after 60 min midpoint @130° C. @ 130° C. after full Catalyst (min) (° C.) cure (° C.) No >60 63/70 132/138 BF.sub.3- 26.2 136/141 175/183 ethylamine Zinc octoate 26.9 118/128 163/173 Zinc octoate/BF.sub.3- 11.7 143/146 168/174 ethylamine (inventive example) Zinc 25.1 120/128 159/165 neodecanoate Zinc 15.0 140/145 165/171 neodecanoate/BF.sub.3- ethylamine (inventive example) Chromium octoate 4.5 106/116  97/118 Chromium 1.6 139/146 155/162 octoate/BF.sub.3- ethylamine (inventive example) Tin octoate 13.0 143/147 157/165 Tin octoate/BF.sub.3- 8.2 152/157 162/171 ethylamine (inventive example) Tin 10.1 139/144 146/157 neodecanoate Tin 7.0 149/154 158/166 neodecanoate/BF.sub.3- ethylamine (inventive example)

[0056] Mixtures of zinc, tin and chromium carboxylates with boron trifluoride ethylamine complex show a significant synergistic catalyst effect on cure speed and Tg build-up.

TABLE-US-00002 TABLE 2 Screening of synergistic acceleration effect on variation of molar ratio and catalyst loading of tin octoate with boron trifluoride ethylamine complex followed by DSC (System: 100 phr Araldite ® GY 250, 24.1 phr Lonzacure ® DETDA 80 (0.135 mol)). Molar ratio Tg onset/ tin octoate/ Tg midpoint BF.sub.3- Time to 95% after 60 Tg onset/ Catalyst ethylamine conversion min @ Tg midpoint loading (inventive @130° C. 130° C. after full (mol) example) (min) (° C.) cure (° C.) 0.0155 0.75 8.2 152/157 162/171 0.0154 0.45 8.0 154/158 162/172 0.0154 1.18 5.8 151/155 154/162 0.0078 0.75 9.9 154/158 173/179 0.0233 0.75 8.1 143/148 150/160 0.0068 0.54 11.4 153/156 175/179 0.0046 1.08 12.5 145/148 175/180 0.0058 1.61 12.0 153/156 173/180

[0057] Increasing tin octoate or catalyst loading leads to increase in cure speed. A too high tin octoate or catalyst loading may lead to a lower final Tg. As a result there is an optimum catalyst loading and molar ratio of tin octoate with boron trifluoride ethylamine complex, namely 0.005-0.015 mol with a molar ratio of 0.5-2.0 for having a fast cure speed in combination with a high final Tg. However, other formulations may be more interesting, if mainly speed of the reaction is of importance.

TABLE-US-00003 TABLE 3 Screening of synergistic catalytic active boron trifluoride complexes with tin octoate at a catalyst loading of 0.016 mol and a molar ratio of tin octoate to boron trifluoride complexes of 0.75 followed by DSC (System: 100 phr Araldite ® GY 250, 24.1 phr Lonzacure ® DETDA 80 (0.135 mol)). Tg onset/ Tg midpoint Time to 95% after 60 Tg onset/ conversion min @ Tg midpoint @130° C. 130° C. after full Catalyst (min) (° C.) cure (° C.) no >60 63/70 132/138 Tin octoate 13.0 143/147 157/165 Tin octoate/BF.sub.3- 8.2 152/157 162/171 ethylamine (inventive example) BF.sub.3-ethyl amine 26.2 136/141 175/183 Tin octoate/BF.sub.3- 5.5 153/159 160/170 phenol (inventive example) BF3-phenol 18.2 147/152 163/172 Tin octoate/BF.sub.3-N- 9.2 149/153 159/166 methylcyclohexylamine (inventive example) BF.sub.3-N- 31.0 118/126 163/170 methylcyclohexylamine Tin octoate/BF.sub.3- 5.5 142/148 143/153 2,4-dimethylaniline in butanediol (inventive example) BF.sub.3-2,4- 21.8 128/135 137/150 dimethylaniline in butanediol Tin octoate/BF.sub.3- 9.0 149/153 165/170 piperidine (inventive example) BF.sub.3-piperidine 29.7 114/124 159/163 Tin octoate/BF.sub.3- 8.1 151/155 157/164 monoisopropylamine (inventive example) BF.sub.3-mono- 26.0 137/142 170/177 isopropylamine

[0058] All mixtures of boron trifluoride complexes with tin octoate show a significant synergistic catalyst effect on cure speed and Tg build-up.

[0059] The above-disclosed subject matter is to be considered illustrative, and not restrictive, and the appended claims are intended to cover all such modifications, enhancements, and other embodiments, which fall within the true scope of the present disclosure. Thus, to the maximum extent allowed by law, the scope of the present disclosure is to be determined by the broadest permissible interpretation of the following claims and their equivalents, and shall not be restricted or limited by the foregoing detailed description.