Imidazole Based Epoxy Resin Curatives

Imidazole Based Epoxy Resin Curatives

PCI Imidazole Epoxy Curatives, Catalysts, and other Additives for Adhesives and Coatings

Imidazole Based Epoxy Resin Curatives

Imidazoles are five membered rings containing two nitrogen's

Cross-linking of epoxy resins using Imidazoles is accomplished by the tertiary amine mechanism. Since the tertiary amines are truly catalysts, there is no stoichiometric level. Because of chain termination and decreased mobility as polymerization proceeds, significant amounts of tertiary amines are required; generally 1 to 10 PHR1

PHR = Parts per Hundred parts of Resin

1. Epoxy Resin Formulator Training Manual, Society of the Plastics Industry

Principal Imidazole Curative Applications

2-MI
2-methylimidazole

Epoxy catalyst, accelerator in dicyandiamide based epoxy systems. 2-MI derived adducts used as latent curatives in "pre-pegs" and coating applications (e.g. corrosion protection/inhibitor, electrical encapsulations).

EMI-24
2-ethyl-4-methylimidazole

Epoxy catalyst in adhesives, coatings, composites. Accelerator for anhydride curing agents. Delays cross-linking of polyester reactions.

EMI-24-LV

Liquid imidazole blend for use in Low Viscosity EMI-24 applications.

2B4MI
2-benzyl-4-methylimidazole

Epoxy catalyst useful in tooling/forms applications, accelerator in organic acid and dicyandiamide based epoxy systems.

EMI-24-CN
1-(2-cyanoethyl)-2-ethyl-4-methylimidazole

Epoxy catalyst for impact and heat resistant adhesives, accelerator for anhydrides (e.g. electrical encapsulation). Catalyst providing extended latency (2 - 3 days) and compatibility with liquid resin systems. Fiber reinforced composite systems. Neutralizer for acid stabilizers in diazo copying compounds. Printing systems for acrylic fabrics with cationic dyes.

2-MICN
1-cyanoethyl-2-methylimidazole

Similar applications to EMI-24-CN product.

2-PHICN
1-(2-cyanoethyl)-2-phenyl-4,5-di(cyanoethoxymethyl)imidazole

Liquid imidazole catalyst providing possibly the most latency (>10 days) and compatibility with liquid resin systems. Reaction rate can be accelerated via addition of Novolak or Bisphenol-A. Excellent accelerator for anhydride and dicyandiamide curing systems. Similar applications to EMI-24-CN product.


"starts with the adduct ion of the pyridine-type nitrogen with the epoxy (1.1, 1.2)."2

2. Kinetics study of imidazole-cured epoxy-phenol resins, Yi-Cheng Chen et al, Dept. of Chem. Eng., National Tai wan University, Journal of Polymer Science Part A: Polymer Chemistry, Vol 37, Issue 16, Pg 3233 - 3242

Imidazole Curing Mechanisms – 2nd Initiation


"results from the ionic nature of the 2,4EMI-phenol interaction (1.4, 1.5)."2

2. Kinetics study of imidazole-cured epoxy-phenol resins, Yi-Cheng Chen et al, Dept. of Chem. Eng., National Tai wan University, Journal of Polymer Science Part A: Polymer Chemistry, Vol 37, Issue 16, Pg 3233 - 3242

Imidazole Curing Mechanisms – Propagation





"consists of three main reaction mechanisms, the epoxide/phenol reaction (1.6), the acid-base reaction (1.3, 1.7), and the epoxide/R-O- reaction (1.8, 1.9)."2

2. Kinetics study of imidazole-cured epoxy-phenol resins, Yi-Cheng Chen et al, Dept. of Chem. Eng., National Tai wan University, Journal of Polymer Science Part A: Polymer Chemistry, Vol 37, Issue 16, Pg 3233 - 3242

Typical Product Performance Data

Product
Recommended
Conc. (PHR)
Working
Pot Life
HDT (°F)

150 (°C)
Gel Time
150 (°C)

150 (°C)
2-MI
1 - 5
4 - 5 hrs
-
35"
2'30"
5'
EMI-24-LV
1 - 5
9 - 10 hrs
325
1'
3'
7'
EMI-24
1 - 5
9 - 10 hrs
315
1'
3'
7'
2B4MI
2 - 4
9 - 10 hrs
-
45'
1'30"
3'30"
EMI-24-CN
4 - 6
3 days
322
1'30"
3'
15'
2-MICN
4 - 5
2 - 2.5 days
318
1'
2'50"
6'
2-PHICN
5 - 7
10 days
350
13'
5'22
15'

Typical Product Properties

2-MI
2-methylimidazole

Stock #: 101491
Pale Yellow to White Crystalline Powder
Assay (GC): 96% min.
Water Content: 0.5% max. (KF)
Melting Point: 133 - 144

EMI-24
2-ethyl-4-methylimidazole

Stock #: 102111
Amber to Yellow Liquid/Solid
Assay (GC): 85% min.
Water Content: 0.4% max. (KF)
Gardner Color: 16 max.

2B4MI
2-benzyl-4-methylimidazole

Stock #: 102698
Yellow Solid
Purity (GC Area): 90% min.

EMI-24-CN
1-(2-cyanoethyl)-2-ethyl-4-methylimidazole

Stock #: 100921
Amber to Brownish Liquid
Assay (GC): 85% min. (sum of 2 regio-isomers)
Water Content: 0.5% max. (KF)
EMI-24 Content: 4.0% max.
Free Acrylonitrile(GC/MS): 500 ppm max.
Gardner Color: less than 16
Viscosity: 200 cps min.
Methanol Content (GC): 2.0% max.

2-MICN
 1-cyanoethyl-2-methylimidazole

Stock #: 100929
Pale Yellow to Amber Liquid
Assay (HPLC): 80% min.
Water Content: 2.0% max. (KF)
2-MI Content: 1.2% max.
Free Acrylonitrile(GC/MS): 2000 ppm max.
Toluene Content (GC): 0.2% max.

2-PHICN
1-(2-cyanoethyl)2-phenyl-4,
5-di-(cyanoethoxymethyl) Imidazole

Stock #: 100924
Light to Dark Brown Viscous Liquid
Assay (HPLC): 90% min.
Acrylonitrile: 500 ppm max.

Additional Additives for Adhesives/Coatings

2-APH
1-acetyl-2-phenylhydrazine

Stock #: 100915
White to Off-White Powder
Assay (HPLC): 97% min.
Loss on Drying: 0.2% max
Melting Point: 127 - 131 C
Metals: Cu 0.4 ppm max., Fe 25 ppm max.

Pilot Production Products

2,4-EMIZ 2-Ethyl-4-Methyl Imidazoline
2B4MIZ 2-Benzyl-4-Methyl Imidazoline
2-EI 2-Ethyl Imidazole
2-PI 2-Phenyl Imidazole
2-PDHMI 2-Phenyl-4,5-Dihydroxymethylimidazole