Accelerator solution and process for curing curable resins

1. Accelerator solution comprising (i) at least one organic solvent, (ii) a manganese salt, a copper salt, or a combination thereof, and (iii) an iron complex of a tetradentate tridentate, pentadentate or hexadentate nitrogen donor ligand according to any of the formulae (I), (II), (III), (IV), (V), and (VI),

the ligand of formula (I) having the following structure:

wherein each R is independently selected from: hydrogen, F, Cl, Br, hydroxyl, C 1-12 -alkylO—, —NH—CO—H, —NH—CO—C 1-12 -alkyl, —NH 2 , —NH—C 1-12 -alkyl, and C 1-12 -alkyl;

R1 and R2 are independently selected from: C 1-24 -alkyl, C 6-10 -aryl, and a group containing a heteroatom capable of coordinating to a transition metal;

R3 and R4 are independently selected from hydrogen, C 1-12 alkyl, C 1-12 -alkyl-O—C 1-12 -alkyl, C 1-12 -alkyl-O—C 6-10 -aryl, C 6-10 -aryl, C 1-12 -hydroxyalkyl, and —(CH 2 ) n C(O)OR5, wherein R5 is independently selected from hydrogen and C 1-4 -alkyl and n ranges from 0 to 4,

X is selected from C═O, —[C(R6) 2 ] y — wherein y ranges from 0 to 3 and each R6 is independently selected from hydrogen, hydroxyl, C 1-12 -alkoxy, and C 1-12 -alkyl;

the ligand of formula (II) having the following structure:

wherein each R1 and R2 independently represents —R 4 —R 5 , R3 represents hydrogen, optionally substituted alkyl, aryl or arylalkyl, or —R 4 —R 5 , each R 4 independently representing a single bond or optionally substituted alkylene, alkenylene, oxyalkylene, aminoalkylene, alkylene ether, carboxylic ester or carboxylic amide, and

each R 5 independently representing an optionally N— substituted aminoalkyl group or an optionally substituted heteroaryl group selected from pyridinyl, pyrazinyl, pyrazolyl, pyrrolyl, imidazolyl, benzimidazolyl, pyrimidinyl, triazolyl, and thiazolyl;

the ligand of formula (III) having the following structure:

wherein each R20 is selected from alkyl, cycloalkyl, heterocycloalkyl, heteroaryl, aryl, and arylalkyl groups optionally substituted with a substituent selected from hydroxy, alkoxy, phenoxy, carboxylate, carboxamide, carboxylic ester, sulphonate, amine, alkylamine and N + (R 21 ) 3 , wherein R 21 is selected from hydrogen, alkanyl, alkenyl, arylalkanyl, arylalkenyl, oxyalkanyl, oxyalkenyl, aminoalkanyl, aminoalkenyl, alkanyl ether, alkenyl ether, and —CY 2 —R 22 , in which Y is independently selected from H, CH 3 , C 2 H 5 , C 3 H 7 and R 22 is independently selected from optionally substituted pyridinyl, pyrazinyl, pyrazolyl, pyrrolyl, imidazolyl, benzimidazolyl, pyrimidinyl, triazolyl and thiazolyl groups, and wherein at least one of R20 is —CY 2 —R 22 ;

the ligand of formula (IV) having the following structure:

wherein Q is independently selected from

wherein p is 4, R is independently selected from hydrogen, C 1-12 -alkyl, CH 2 CH 2 OH, pyridin-2-ylmethyl, and CH 2 COOH;

R 1 , R 2 , R 3 , R 4 , R 5 and R 6 are independently selected from H, C 1-12 -alkyl, and C 1-12 -alkylhydroxy;

the ligand of formula (V) having the following structure:

wherein R 1 is independently selected from H and linear or branched, substituted or unsubstituted C 1-20 -alkyl, -alkylaryl, -alkenyl or -alkynyl;

and all nitrogen atoms in the macropolycyclic rings are capable of coordinating to transition metals;

the ligand of formula (VI) having the following structure:

(R 17 )(R 17 )N—X—N(R 17 )(R 17 )  (VI)

wherein X is selected from —CH 2 CH 2 —, —CH 2 CH 2 CH 2 —, and —CH 2 C(OH)HCH 2 —; and each R 17 is independently selected from the group consisting of alkyl, cycloalkyl, heterocycloalkyl, heteroaryl, aryl and arylalkyl groups optionally substituted with a substituent selected from hydroxy, alkoxy, phenoxy, carboxylate, carboxamide, carboxylic ester, sulphonate, amine, alkylamine and N + (R 19 ) 3 , wherein R 19 is selected from hydrogen, alkanyl, alkenyl, arylalkanyl, arylalkenyl, oxyalkanyl, oxyalkenyl, aminoalkanyl, aminoalkenyl, alkanyl ether, alkenyl ether, and —CY 2 —R 18 , in which Y is independently selected from H, CH 3 , C 2 H 5 , C 3 H 7 and R 18 is independently selected from an optionally substituted heteroaryl group selected from pyridinyl, pyrazinyl, pyrazolyl, pyrrolyl, imidazolyl, benzimidazolyl, pyrimidinyl, triazolyl and thiazolyl; and wherein at least two of R 17 are —CY 2 —R 18 .

2. The accelerator solution according to claim 1 wherein the iron complex comprises a nitrogen donor ligand according to formula (I).

3. The accelerator solution according to claim 1 wherein the manganese salt is selected from Mn(II) chloride, Mn(II) nitrate, Mn(II) sulphate, Mn(II) lactate, Mn(II) 2-ethyl hexanoate, Mn(II) octanoate, Mn(II) nonanoate, Mn(II) heptanoate, Mn(II) neodecanoate, Mn(II) naphthenate, and Mn(II) acetate.

4. The accelerator solution according to claim 1 wherein the copper salt is selected from Cu(II)acetate, Cu(I)chloride, Cu(II) octanoate, Cu(II) nonanoate, Cu(II) heptanoate, Cu(II) neodecanoate, and Cu(II) naphthenate.

5. The accelerator solution according to claim 1 comprising both a copper salt and a manganese salt.

6. The accelerator solution according to claim 1 additionally comprising a promoter selected from amines and metal carboxylates.

7. The accelerator solution according to claim 6 wherein the promoter is selected from the group consisting of triethyl amine, dimethylaniline, diethylaniline, N,N-dimethyl-p-toludine, 1,2-(dimethyl amine)ethane, diethyl amine, triethanol amine, dimethylamino ethanol, diethanol amine, monoethanol amine, and the 2-ethyl hexanoates, octanoates, nonanoates, heptanoates, neodecanoates, and naphthenates of Na, K, Li, Ba, Cs, Ce, Mg, Ca, Zn, Cu, Ni, Mn, Sn, Cr, Au, Ag, Pd, and Pt.

8. The accelerator solution according to claim 1 wherein the iron complex is present in an amount of 0.01-10 wt % Fe, based on the total weight of the accelerator solution.

9. The accelerator solution according to claim 1 wherein the manganese salt is present in an amount of 0.01-10 wt %, based on the total weight of the accelerator solution.

10. The accelerator solution according to claim 1 wherein the copper salt is present in an amount of 0.01-10 wt % based on the total weight of the accelerator solution.

11. A method for curing a curable resin comprising contacting a curable resin with an accelerator solution according to claim 1 .

12. The method according to claim 11 wherein the curable resin is an unsaturated polyester resin, a (meth)acrylate resin, or a vinyl ester resin.

13. The method according to claim 12 wherein the curable resin is an unsaturated polyester resin selected from the group consisting of ortho-resins, iso-resins, iso-npg resins, and dicyclopentadiene (DCPD) resins.

14. The method according to claim 12 further comprising adding one or more ethylenically unsaturated monomers to the curable resin.

15. The accelerator solution according to claim 5 wherein the manganese salt is selected from Mn(II) chloride, Mn(II) nitrate, Mn(II) sulphate, Mn(II) lactate, Mn(II) 2-ethyl hexanoate, Mn(II) octanoate, Mn(II) nonanoate, Mn(II) heptanoate, Mn(II) neodecanoate, Mn(II) naphthenate, and Mn(II) acetate.

16. The accelerator solution according to claim 5 wherein the copper salt is selected from Cu(II)acetate, Cu(I)chloride, Cu(II) octanoate, Cu(II) nonanoate, Cu(II) hoptanoate, Cu(II) neodecanoate, and Cu(II) naphthenate.

17. The accelerator solution according to claim 16 further comprising a promoter selected from amines and metal carboxylates.

18. The accelerator solution according to claim 17 wherein the promoter is selected from the group consisting of triethyl amine, dimethylaniline diethylaniline, N,N-dimethyl-p-toludine 1,2-(dimethyl amine)ethane diethyl amine, triethanol amine, dimethylamino ethanol, diethanol amine, monoethanol amine, and the 2-ethyl hexanoates, octanoates, nonanoates, heptanoates, neodecanoates, and naphthenates of Na, K, Li, Ba, Cs, Ce, Mg, Ca, Zn, Cu, Ni, Mn, Sn, Cr, Au, Ag, Pd, and Pt.