Liquid hardening
The present invention relates to a curing agents for air-drying alkyd-based resins, coatings, such as paint, varnish or wood stain, inks and linoleum floor coverings, based on an iron/manganese complex containing tetradentate, pentadentate or hexadentate nitrogen donor ligands.
1. A curable liquid medium comprising:
a) from 1 to 90 wt % of an alkyd-based resin; and,
b) from 0.0001 to 0.1 wt % of a siccative, wherein the siccative is an iron or manganese complex of a tetradentate, pentadentate or hexadentate nitrogen donor ligand, wherein the ligand is:
wherein each R is independently selected from: hydrogen, F, Cl, Br, hydroxyl, C1-C4-alkylO—, —NH—CO—H, —NH—CO—C1-C4-alkyl, —NH2, —NH—C1-C4-alkyl, and C1-C4-alkyl;
R1 and R2 are independently selected from:
C1-C24-alkyl,
C6-C10-aryl, and,
a group containing a heteroatom capable of coordinating to a transition metal;
R3 and R4 are independently selected from hydrogen, C1-C8 alkyl, C1-C8-alkyl-O—C1-C8-alkyl, C1-C8-alkyl-O—C6-C10-aryl, C6-C10-aryl, C1-C8-hydroxyalkyl, and —(CH2) n C(O)OR5
wherein R5 is independently selected from: hydrogen, C1-C4-alkyl, n is from 0 to 4, and mixtures thereof; and,
X is selected from C═O, —[C(R6) 2 ] y - wherein Y is from 0 to 3 each R6 is independently selected from hydrogen, hydroxyl, C1-C4-alkoxy and C1-C4-alkyl.
2. A curable liquid medium according to claim 1 , wherein in formula (I) the group containing a heteroatom capable of coordinating to a transition metal is pyridin-2-yl.
3. A curable liquid medium according to claim 2 , wherein the heteroatom donor group is unsubstituted pyridinyl.
4. A curable liquid medium according to claim 1 , wherein in formula (I) X is C═O or C(OH)2.
5. A curable liquid medium according to claim 1 , wherein in formula (I): R3=R4 and selected from —C(O)—O—CH3, —C(O)—O—CH2CH3, —C(O)—O—CH2C6H5 and CH2OH.
6. A curable liquid medium according to claim 1 , wherein in formula (I) at least one of R1 or R2 is pyridin-2-ylmethyl and the other is selected from —CH3, —C2H5, —C3H7, —C4H9, C6H13, C8H17, C12H25, and C18H37.
7. A curable liquid medium according to claim 1 , wherein the iron ion is selected from Fe(II) and Fe(III) and the manganese ion selected from Mn(II), Mn(III), and Mn(IV).
8. A curable liquid medium according to claim 1 , wherein the content of the siccative is between 0.0001 and 0.5% w/w.
9. A curable liquid medium according to claim 1 further comprising between 0.001% and 0.1% of an antioxidant selected from the group consisting of: di-tert-butyl hydroxy toluene, Ethoxyquine, α-tocopherol, and 6-hydroxy-2,5,7,8-tetra-methylchroman-2-carboxylic acid.
10. A curable liquid medium according to claim 9 , wherein the composition comprises between 0.002 and 0.05% of antioxidant.
11. A curable liquid medium according to claim 9 , wherein the antioxidant is selected from α-tocopherol.
12. A curable liquid medium according to claim 1 that is stored under nitrogen or argon gas.
13. A curable liquid medium according to claim 1 , containing between 0.001 and 90% of ethylene glycol, diethylene glycol, dipropylene glycol, glycerol, pentaerythritol, dipenta erythritol, neopentyl glycol, trimethylol propane, trimethylol ethane, di-trimethylol propane and 1,6-hexane diol.
14. A curable liquid medium according to claim 13 , containing 0.1 and 50% of ethyleneglycol or glycerol.
15. A curable liquid medium according to claim 14 , containing 0.3 and 5% of ethyleneglycol or glycerol.
16. A curable liquid medium according to claim 1 , containing between 0.001 and 2.5% of lead, zirconium, bismuth, barium, vanadium, cerium, calcium, lithium, strontium, and zinc.
17. A curable liquid medium according to claim 1 when cured.