Curing agents or hardeners or crosslinker are very important for the final specifications of the cured products. Curing agents are neccesary to convert epoxy resin to hard thermoset network.
Cross-linking = Curing
Epoxy-amine cross-linking through the reaction of the amine group with the epoxide group.
An epoxy group reacts with ONE amine-hydrogen, one hydrogen attached directly to a Nitrogen atom. Every time that an epoxy group is opened; one Hydroxyl group is generated
The linking of the chains with each other; cross linking. In order for this to occur it is necessary that each amine molecule will have more-than-two active amine-hydrogen’s. The inter-linking of larger molecules causes a rapid increase of the observed viscosity.
possible tertiary amine catalysed hydroxyl-cure temperature helps
RECURE curing agents from REAKSIYON KIMYA are used with our epoxy resins REPOX RC 8132, REPOX RC 815 and REPOX RC 820.
Epoxy resins consist of two components, PART A consists of an epoxy resin and Part B is the epoxy curing agent.
There are lots of curing agents available. Commonly used epoxy curing agents for insdustrial coatings are Aliphatic, Cycloaliphatic, Aromatic Amines and Polyamides, Amidoamines, Amidoamines, Aliphatic Amine Adducts and Phenalkamines.
The selection of curing agent plays a major role in determining many of the properties of the final cured epoxy. The selection of a curing agent will be determined by:
| Film Flexibility | Adhesion | Chemical Resistance Acids | Chemical Resistance Solvens | Chemical Resistance Water | Blush Resistance | Color Stability | Low Temp. Application | Corrosion Resistance | Viscosity | |
| Aliphatic Amines | ● | ●●● | ●●●●● | ●●●●●●● | ●● | ● | ●●● | ●●●●●● | ● | ●●●●●● |
| Cycloaliphatic Amines | ●●●● | ●●●● | ●●●●●● | ●●●●● | ●●●● | ●●●● | ●●●●● | ●●●● | ●●●● | ●●●●●●● |
| Aromatic Amines | ●●● | ● | ●●●●●●● | ●●●● | ●●● | ●●● | ● | ● | ●● | ●●●● |
| Polyamides | ●●●●●●● | ●●●●●●● | ● | ●●● | ●●●●●●● | ●●●●●●● | ●●●●●●● | ●●● | ●●●●●●● | ● |
| Amidoamines | ●●●●●● | ●●●●● | ●●● | ● | ●●●●● | ●●●●● | ●●●●●● | ●● | ●●●●●● | ●●●●● |
| Aliphatic Amine Adducts | ●● | ●● | ●●●● | ●●●●●● | ● | ●● | ●●●● | ●●●●● | ●●● | ●●● |
| Phenalkamines | ●●●●● | ●●●●●● | ●● | ●● | ●●●●●● | ●●●●●● | ●● | ●●●●●●● | ●●●●● | ●● |
•The curing agents are key actors which specifies the physical properties of the resin and the curing agents or hardeners are main materials to use with epoxy resin as a reactant.
WHAT IS EPOXY RESIN ?
Epoxy Resin is a class of thermoset polymer which contains at least two epoxide groups.
The most widely used epoxy resins are diglycidyl ethers of Bisphenol A (DGEBPA) obtained from bisphenol A (BPA) and epichlorohydrin (ECH).
There are also other epoxy resins such as
•Bisphenol F Epoxy Resins
•Novolaks Epoxy Resins
•Aliphatic Epoxy Resins
Bisphenol A Epoxy Resin Synthesis
(Bisphenol A) (Epichlorohydrin)
Characteristics of Bisphenol A Epoxy Resins
| Resin Type | Epoxy Equivalent Weight (EEW) | Viscosity (m.Pa.s 25C) | Crosslinking (Group Used |
| Standard Liquid | 185-192 | 12-14 | Epoxide |
| Type 1 | 525-550 | 0.7–0.96 | Epoxide |
| Type 2 | 600-700 | 0.92-1.36 | Epoxide |
| Type 4 | 800-900 | 1.5-2.5 | Epoxide or OH |
| Type 7 | 1700-2300 | 5-10 | OH |
| Type 9 | 2300-2800 | 10-25 | OH |
Epoxy Applications
