Curing agents polyamide

Authors R.B. Prime and E. Sacher [51] (1972) System Resin DGEBA (DOW DER 332) Curing Agent polyamide (General Mills Versamid 140) without purification... 

Curing Agent polyamide (General Mills b. System 2 ... 

When compared to other curing agents, polyamides and amidoamines offer the following three unique features. 

Hazardous Decomp. Prods. Heated to decomp., emits toxic fumes of NOx Uses Epoxy resin curing agent polyamide resins oil additives ion exchange resins Manuf./Distrib. Aldrich http //www.sigma-aldrich.com] Fluka http //www.sigma-aldrich.com] Tosoh http //www.tosoh.co.jp... 

The two-part epoxy adhesive, readily available in hardware stores or other consumer outlets, comes in two tubes. One tube contains the epoxy resin, the other contains an amine hardener. Common diamine room temperature epoxy curing agents are materials such as the polyamides, available under the trade name Versamid. These polyamides are the reaction products of dimer acids and aUphatic diamines such as diethylenetriamine [111-40-0] ... 

Aliphatic polyamines, amine adducts and polyamides react with epoxide resins at normal temperatures to give complexes with outstanding chemical resistance. Paints based on this type of reaction must be supplied in two separate containers, one containing the epoxide resin and the other the curing agent , the two being mixed in prescribed proportions immediately before use. 

The FM 123-2, supplied as a supported film on a knitted mlcro-fllament nylon carrier, was applied directly to one pretreated (SAA or FPL) A1 panel (15 cm x 15 cm x 0.3 cm). A second panel was then pressed onto the exposed adhesive side and the "sandwich structure was subsequently cured at 120°C under 40 psi for 1 hr. A 1 1 1 mixture of the epoxy-polyamide formulation (EPON resin Versamld curing agent thinner, MIL-T-81772) was sprayed onto prepared 7075-T6 specimens to a thickness (dry) of 0.015 - 0.023 cm. 

Curing agents account for much of the potential hazard associated with use of epoxy resins. There are several major types of curing agents aliphatic amines, aromatic amines, cycloaliphatic amines, acid anhydrides, polyamides, and catalytic curing agents. The latter two types are true catalysts, in that they do not participate in the curing process. 

The two homologous aliphatic diamines are commonly used as bifunctional monomers for polycondensation reactions. Hexamethylenediamine or 1,6-diaminohexane, Cf,H16N2 (CAS No. 124-09-4, PM Ref.No. 1840), which is most well-known as a polyamide (Nylon 66) monomer, is also copolymerized with sebacic acid to form Nylon 6/ 10, or with isophthalic acid. Besides that, it is applied as a curing agent for expoxy... 

Two curing agents that have found their way into many epoxy adhesive formulations are the polyamides and amidoamines. These are commonly used in the hardware store variety two-part epoxy resins that cure at room temperature. Both are reaction products of aliphatic amines, such as diethylenetriamine, and should be included under the subclassification of modified amines. However, these products have such widespread and popular use, they are addressed here as a separate classification. 

Polyamide curing agents are the reaction products of dimerized fatty acids and aliphatic amines such as diethylenetriamine. This introduces a bulky, oil-compatible, C36 carbon group between the amine sites. Similar to the diglycidyl ether adducts of aliphatic amine, they are manufactured by adding the fatty acid to an excess of amine. They are available in a range of viscosities that can be achieved by varying the amine/acid molar ratio in the reaction. 

The Versamid series of curing agents were the original and best known polyamide curing agents. Current commercial polyamide curing agents and their properties are shown in App. D. More recently developed polyamides provide lower viscosity, better compatibility with epoxy resins, and better cure profiles under adverse conditions. 

Amidoamine or polyamidoamine curing agents have reactivity with DGEBA epoxy resins that is similar to the polyamides. However, they are lower-viscosity products and are also lower in color. Amidoamines are derivatives of monobasic fatty carboxylic acids and aliphatic polyamines. Since the amidoamines have only one amide group per molecule, they are lower in molecular weight, viscosity, and amine functionality than the polyamides. 

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