Amine-epoxy resin adduct

Primary or secondary amine/epoxy resin adducts are also used as accelerators for 10-cured compositions. Mixtures of polyalkylene diamines, imidazole (33), and 10 have been heat blended with epoxy resins to give curable compositions which show excellent flexibility and adhesion compared to compositions prepared without the polyalkylene diamines. Adducts of piperazine (34) or homopiperazine (35) with DGEBA-type resins have been used in 10-cured epoxy formulations both to promote shelf stability and to accelerate cure. DGEBA-type resins cured with 10 and 2 1 DGEBA-resin-iV-methylpiperazine adduct gel in 90s at 160°F, yet have a shelf life of 50 days at 50 C. If the unsubstituted piperazine is used in the... 

Resinous adducts, 10 394 Resinous odor, 3 229t Resins. See also Epoxy resins Lacquer resins Novolac resins Phenolic resins Resole resins Thermoplastic resins acidic cation-exchange, 12 191 advanced materials, 1 693 antilipemic agents, 5 141 aromatic glycidyl amine, 10 372—373 chromatographic, 14 383-384 for coatings, 7 95-107 derived from furfuryl alcohol, 12 271— 272... 

BMI/amine Michael adduct resins may be further modified and blended with other thermosets or reactive diluents to achieve either specific end-use properties or processability. Epoxy resins are very suitable for the modification of BMI/primary amine adducts, because the secondary amine functionality in the aspartimide structure is a curative for the epoxy group. 

Heat resistant resin compositions based on BMI/aminophenol-Epoxy blends are achieved by reacting a BMI/p-aminophenol 1 1 adduct with epoxy resin (62). Both the secondary amine and phenol functionality may react with the epoxy resin and subsequently cure through an imidazole catalyst. Imidazole catalysts promote both the epoxy/phenol reaction and the anionic maleimide crosslinking. The formation of a 1 2 BMI/aminophenol adduct, as in Fig. 20, is claimed in a patent (63). The hydroxy terminated BMI/aminophenol adduct is an advantageous curing agent for epoxy resins when high temperature performance is desired. 

Epoxy adduct of aromatic amine (25) Araldite (Series) Epoxy resins... 

The cure kinetics of some epoxy resin powder coating composition were reported by Olcese et al.108). These were mixtures of BADGE resins with DICY and an epoxide-amine adduct or an imidazole as accelerator, together with TiOz and plasticisers. Data from DSC scans were analysed using Eq. (2-12) to obtain the apparent activation energy, E. Also Eq. (2-13) and (2-13 a) were used to obtain estimates of E and order... 

Epoxy-amine adducts are produced to provide curing agents that have reduced skin and eye irritation and better flexibility than unmodified amines. These epoxy amines are formed by the reaction of either a primary or secondary amine with an epoxy resin. They are more fully described in Chap. 5. 

Suitable curatives for the polysulfide-epoxy reaction include liquid aliphatic amines, liquid aliphatic amine adducts, solid amine adducts, liquid cycloaliphatic amines, liquid amide-amines, liquid aromatic amines, polyamides, and tertiary amines. Primary and secondary amines are preferred for thermal stability and low-temperature performance. Not all amines are completely compatible with polysulfide resins. The incompatible amines may require a three-part adhesive system. The liquid polysulfides are generally added to the liquid epoxy resin component because of possible compatibility problems. Optimum elevated-temperature performance is obtained with either an elevated-temperature cure or a postcure. 

The binders used in these ambient-cured formulations are generally low molecular weight reactive epoxy resins. These are cured with either amine or amine adducts to give the best chemical resistance, or with polyamide to give better water resistance, weathering and recoating properties (Dow Chemical Company, undated a). 

In our own work towards cathodic systems with high bare steel corrosion resistance we first prepared a number of epoxy resin/ amine adducts of the formal composition ... 

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). 

Polyamines. Aliphatic polyamines cure epoxy resins via their epoxy groups at ambient temperature. Excess amine is generally prereacted with the epoxy resin to form a polyamine adduct. Amines react with monomeric or dimeric fatty acids to form polyamidoamines. Polyamine-adduct-cured epoxy resins have a high chemical resistance. Polyamidoamine-cured epoxy resins exhibit good adhesion and flexibility. 

Epoxy resins cured with aminoamide resins or amine adducts are often used for large metal constructions. Paints based on these resins are normally applied in four layers. Epoxy coatings form films that are resistant to organic solvents and a wide range of chemicals. Epoxy coatings are currently used for the majority of steel and aluminum constructions, but are also suitable for use on other construction materials (e.g., concrete). They can protect buildings in chemical plants and nuclear power... 

Anticorrosive primer formulations are based on epoxy resins that react at ambient temperature with amine adducts, aminoamide resins, or isocyanates (two-pack primers). Zinc or strontium chromates are used as anticorrosive pigments. These electrolytically active pigments prevent dangerous filiform corrosion. Extensive development work is being carried out on chromate-free aircraft primers [11.8], [11.9]. 

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. 

Chem. Descrip. Aliphatic amine adduct in solvents Uses Epoxy curing agent for solv.-based coatings with solid epoxy resins Features Offers faster cure times, lower reaction temps Properties Gardner 4 max. color sp.gr. 0.98 dens. 8.2 Ib/gal vise. 4-7 poise amine no. 166-240 thru cure 17 h R.T. 48% solids... 

Such paints are prone to surface exudation. The risk of getting this fault can be minimized by allowing the paint to stand 12-16 hours before it is used. This is quite safe, since pot-lives are arranged to be about 48 hours at normal temperatures. An alternative, more reliable method is to pre-react some epoxy resin with an excess of amine, so that an adduct containing unreacted amino hydrogen atoms is produced. 

Ester and ketone solvents, which react with amines, must not be present. The adduct is a polyamine and can therefore be used to crosslink epoxy resins. It has advantages in that it is odourless (simple amines are unpleasant to handle), part-reacted (which speeds up drying) and free from simple amines (which cause exudation). It can be seen now why it is an advantage to age paints cured by simple amines amine adducts are formed during the ageing. 

Surface- mount adhesives DGEBA Resin (GY 6010, DER 331, Shell 828) 40-50% Amine epoxy adduct or polyamide (Versamide , Ancamide, Aradur , etc.) 20-30% Mineral filler and thixotrope 12-25% Amicon 125 D3, Amicon E 6752, Epo-Tek 70E-4 Chipbonder series (Loctite), Epi-bond 7275 (Vantico)... 

Resin acid dimer adducts with maleic anhydride and acrylic acid were also used to prepare epoxy resins [107, 109]. The epoxy precursors were prepared by the reaction of the Diels-Alder adducts with di(ethanol)amine, followed by treatment with epychlorydrine under alkaline conditions, as shown in Fig. 4.21 for the acrylic acid adduct [109]. After curing, the ensuing materials produce high stability coats [109]. 

FIGURE 3.29 Amine adducts for cure of epoxy resins. 

This adduct is formulated with the epoxy resin during adhesive manufacture. Amine-terminated RLPs (ATBNs) are used as hardeners in two-part epoxy systems. These are prepared by reacting a CTBN with N-aminoethylpiperazine. 

Epoxy adduct n. Resin having all the required amine incorporated but requiring additional epoxy resin for curing. 

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