Epoxy poly amine

Ambient-cure systems are often based on lower molecular-weight soHd epoxy resins cured with aUphatic polyamines or polyamides. Curing normally occurs at ambient temperatures with a working life (pot life) of 8—24 h, depending on the formulation. Epoxy—poly amine systems are typically used for maintenance coatings in oil refineries, petrochemical plants, and in many marine appHcations. Such coverings are appHed by spray or bmsh. These are used widely where water immersion is encountered, particularly in marine appHcations (see COATINGS, MARINE). 

The term epoxy is familiar to nonchemists because of the widespread use of epoxy glues and resins. These are crosslinked polyether thermoplastics made from a liquid resin which is typically a mixture of bisphenol A diglycidyl ether (70) and a polymer (71 Scheme 86). The liquid resin is cured or hardened to the final resin by mixing with a crosslinking reagent, which can be an acid, a di- or poly-alcohol, or a di- or poly-amine (Scheme 86). 

A great variety of aromatic diamines and aliphatic di- and poly-amines are used as epoxy resin curing agents, and tert-amines can act as catalysts for anionic epoxide homopolymerisation. 

Aliphatic poly amines. These are low-viscosity materials with high reactivity and fast cure at ambient temperatures. The basic reaction of aliphatic amines with epoxy resin is shown in Figure 2.7. 

Epotuf Hardener. [Reichhold] Poly-amine, polyamide, w anhydride epoxy hardener. 

Macro-diisocyanates based on the reaction of an excess of 2,4-toluene diisocyanate with different poly(dimethylsiloxane)diols of different lengths have been prepared by Nikolaev et al. [71]. These macro-diisocyanates were reacted with 2 in stoichiometric proportions and the resulting adduct (22) was cured with a commercial epoxy resin in the presence of what was termed poly(ethylene)-poly(amine) at room temp-cerature, 80, and 100°C. The mechanical and thermal properties of steel-to-steel assemblies joined by these adhesives were better than those obtained using more common binders. 

Amidoamines are derivatives of monobasic carboxylic acids (such as ricinoleic acid) and an aliphatic polyamine. Like the polyamides, amidoamines can be used over a range of additive levels to enhance a specific property. The reactivity of amidoamines with epoxies is similar to that of polyamides. However, amidoamines offer several advantages over aliphatic amines and poly amines more convenient mix ratios, increased flexibility, better moisture resistance than aliphatic poly amines, and lower viscosity and color than polyamides. 

Various poly amines also are useful as curatives for epoxy adhesives. An example of a simple polyamine is diethylenetriamine (DETA) ... 

The main disadvantages of the use of poly amines are (1) coating systems blush or sweat under conditions of high humidity, (2) polyamines are skin sensitizers and need special handling and (3) they need precise mixing because small amounts of polyamines are used for the curing of epoxy resins. 

Some commercial durable antistatic finishes have been Hsted in Table 3 (98). Early patents suggest that amino resins (qv) can impart both antisHp and antistatic properties to nylon, acryUc, and polyester fabrics. CycHc polyurethanes, water-soluble amine salts cross-linked with styrene, and water-soluble amine salts of sulfonated polystyrene have been claimed to confer durable antistatic protection. Later patents included dibydroxyethyl sulfone [2580-77-0] hydroxyalkylated cellulose or starch, poly(vinyl alcohol) [9002-86-2] cross-linked with dimethylolethylene urea, chlorotria2ine derivatives, and epoxy-based products. Other patents claim the use of various acryUc polymers and copolymers. Essentially, durable antistats are polyelectrolytes, and the majority of usehil products involve variations of cross-linked polyamines containing polyethoxy segments (92,99—101). 

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