Of amine-cured epoxy coatings

Degradation of Amine-Cured Epoxy Coating on Cold-Rolled Steel... 

Figure 1. FTIR-RA spectra of amine-cured epoxy coating on cold-rolled steel before and after exposure to 40 C and 80% RH...

Fourier transform Infrared spectroscopy has been shown to be an excellent tool for surface and Interface studies (.2), In this paper, the application of reflection/absorption Fourier transform Infrared spectroscopy (FTIR-RA) for studying the degradation of amine-cured epoxy and polybutadiene coatings on cold-rolled steel after exposure to a warm, humid environment is reported. 

S. G. Croll, "Residual Stress in a Solventless Amine-Cured Epoxy Coating", J. of Coatings Technology, Vol. 51, 659. 49-55, Dec. 1979. 

Higher molecular weight epoxy resin hardeners such as fatty polyamides do not have the problems associated with amines and amine adducts. These reaction products of dimer and trlmer acids with polyfunctional amines provide films with fewer surface discontinuities. Polyamide cured epoxy coatings are more forgiving than amine cured epoxy coatings since they require less demanding surface preparation. Also, mix ratios are less critical for poly-amide/epoxy coatings (56). 

The reactive groups attached to the molecules of an epoxy resin can react with several curing agents, such as amines, anhydrides, acids, mercaptans, imidazoles, phenols and isocyanates, to create covalent intermolecular bonds and thus to form a three-dimensional network. Among these compounds, due to the enhanced environmental stability of amine-cured epoxy resin (Dyakonov et al., 1996), primary and secondary amines are the curing agents most commonly used in particular aliphatic or cycloaliphatic amines for low-temperature epoxy systems as adhesives or coatings and aromatic amines to produce matrices for liber-reinforced composites (Pascault and Williams, 2010). In Fig. 5.14 the structures of both an aliphatic and an aromatic amine are shown. 

Figure 11.18 Microcapsule-based self-reporting material amine cured epoxy coating mixed with microcapsules that contained 2, 7 -dichlorofluorescein (DCF), (a) Schematic of the release of DCF solution from broken microcapsules into a crack or scratch where the dye encounters the amine groups of the resin, resulting in colour change, (h) Colour change of a DCF solution in the presence of an amine, (c) Self-reporting properties of the described material.

Rezig A, Nguyen T, Martin D, Sung L, Gu X, Jasmin J, Martin J (2006) Relationship between chemical degradation and thickness loss of an amine-cured epoxy coating exposed to different UV environments. JCT Res 3(3) 173-184... 

The formation of networks by addition polymerization of multifunctional monomers as minor components included with the monofunctional vinyl or acrylic monomer is industrially important in applications as diverse as dental composites and UV-cured metal coatings. The chemorheology of these systems is therefore of industrial importance and the differences between these and the step-growth networks such as amine-cured epoxy resins (Section 1.2.2) need to be understood. One of the major differences recognized has been that addition polymerization results in the formation of microgel at very low extents of conversion (<10%) compared with stepwise polymerization of epoxy resins, for which the gel point occurs at a high extent of conversion (e.g. 60%) that is consistent with the... 

A number of antioxidants were examined for solubility in the monomer, effect upon the photoinitiator, UV stability, effect upon physical properties of the cured coating and their effectiveness as stabilizers. The addition of hydrogen donors, HD-2 or HD-3, or a hindered amine light stabilizer, HALS-1, improves the stability of a cured epoxy acrylate system with a minimal change in the physical properties of the resin. DSC and oxygen absorption measurements show that the secondary hindered amine, HALS-1, imparts the best stability to the resin. 

Elastomer modification of two-package epoxy coatings has been carried out either with rubber addition to the epoxy component or to the hardener component. Amine-reactive nitrile liquids have been examined extensively in polyamide cured epoxy coatings. The... 

Comparisons of the properties of solvent-free Hquid coatings based on unmodified bisphenol A epoxies cured with varying amine hardeners are shown in Table 6. Examples include diethylenetriamine [111-40-0] H2NC2H4NHC2H4NH2 (7), triethylenetetramine [112-24-3] ... 

A waterborne system for container coatings was developed based on a graft copolymerization of an advanced epoxy resin and an acryHc (52). The acryhc-vinyl monomers are grafted onto preformed epoxy resins in the presence of a free-radical initiator grafting occurs mainly at the methylene group of the aHphatic backbone on the epoxy resin. The polymeric product is a mixture of methacrylic acid—styrene copolymer, soHd epoxy resin, and graft copolymer of the unsaturated monomers onto the epoxy resin backbone. It is dispersible in water upon neutralization with an amine before cure with an amino—formaldehyde resin. 

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