Curing agents for epoxies

Uses. 3-Pentenenitrile, 3PN, is used entirely by the manufacturers to make adiponitrile. i7j -2-Pentenenitrile, 2PN, can be cycli2ed catalyticaHy at high temperature to produce pyndine, a solvent and agncultural chemical intermediate. 2PN is also chlorinated to manufacture pentachloropyndine, an intermediate in the insecticide Dursban produced by Dow. Addition of ammonia to 2PN foUowed by reduction leads to 1,3-pentadiamine (Dytek ep), which is used as a curing agent for epoxy coatings and as a chain modifier in polyurethanes. 

In addition, boron trifluoride and some of its adducts have widespread appflcation as curing agents for epoxy resins (qv), and in preparing alcohol-soluble phenoflc resins (qv) (41). 

Process Raw Material. Industrial solvents are raw materials in some production processes. Eor example, only a small proportion of acetone is used as a solvent, most is used in producing methyl methacrylate and bisphenol A. Alcohols are used in the manufacture of esters and glycol ethers. Diethylenetriamine is also used in the manufacture of curing agents for epoxy resins. Traditionally, chlorinated hydrocarbon solvents have been the starting materials for duorinated hydrocarbon production. 

BMI—y -aminophenol adducts can further react with epoxy resia and subsequendy be cured with imida2ole catalyst. 1 2 BMI—aminophenol adducts have been used as curing agents for epoxy resia (37). 

Cyclic acid anhydrides such as maleic, dodecylsuccinic, hexahydrophthalic, phthalic, phyromellitic, etc. are widely employed as curing agents for epoxy resins. They form esters with epoxy resins. These resins have better thermal stability and good electrical insulation and chemical resistance expect to alkalis. 

Lin, S. C., "Novel Cross-linking System - N-Cyanourea and Its Adducts as Latent Curing Agent for Epoxy Resins," U.S. Patent 4 379 728, 1983. 

Uses. As a curing agent for epoxy and other resins and as a vinyl plasticizer also found in anticorrosive surface coatings, polymers, paints, dyes, and pharmaceuticals... 

Diglycidyl ether of bisphenol-A (DGEBA), epoxy resin (YD 128, Kuk Do Chem., Mn = 378), and bisphenol-A dicyanate (BPACY, Arocy B-10, Ciba-Geigy) were used as the thermoset resin. 4,4 -diaminodiphenyl sulfone (DDS, Aldrich Chem. Co.) was used as a curing agent for epoxy. Polyetherimide (PEI, Ultem 1000, General Electric Co., M = 18,000) and 2-methyl imidazole (2MZ, Aldrich Chem. Co.) were used as the thermoplastic modifier and catalyst. 

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. 

Tertiary amines (TA) may be utilized both as independent curing agents for epoxy resins and as catalysts in the reaction of epoxy compounds with alcohols, phenols, carboxylic adds and their anhydrides i - 5. Besides, the three-... 

The molecular structure of epoxy/metal interphases in the presence of an amino coupling agent was studied by Boerio and co-workers [28] by IR and by XPS. The formation of amide and imide groups in the interphase provided evidence of chemical reaction between the silane primer and the curing agent for epoxy resin. 

Kiyono, S. 1997. Heat resistant epoxy resin composition having excellent stability at normal temperature and curing agent for epoxy resin. U.S. Patent 5,610,209. 

Amines are one of the most important curing agents for epoxy resins. They provide fast cures with a relatively high crosslink density. Unmodified amine cured epoxy resins are generally too brittle for adhesive applications, and so there are many derivatives that have been developed. More information on amine curing agents can be found in Chap. 5. 

Aromatic amines are widely used as curing agents for epoxy resins. However, they are not used as widely in adhesive formulations as they are in composites, molding compounds, and castings. They offer cured epoxy structures with good heat and acid resistance. 

As a family of curing agents for epoxy resins, the amidoamines are lower in viscosity than the polyamides. They exhibit very good adhesive properties due to their chemical structure and easy penetration. Amidoamine cured epoxy adhesives have shown very good properties on concrete and other porous substrates. They cure extremely well under humid conditions. In fact amidoamine cured epoxy formulations have been used to cure underwater in certain applications. A typical general-purpose room temperature curing epoxy-amidoamine system is described in Table 11.7. This adhesive is used as a general-purpose metal-to-metal adhesive and body solder in the automotive industry. 

Amine curing agents for epoxies are poor in oxidizing acids. Anhydride curing agents are poor in caustics. 

Technical Bulletin, The Curezol Series Imidazole Group Curing Agents for Epoxy Resins , Shikoku Fine Chemical Corp., Okura and Co. Inc., New York, NY, U.S.A. 

Table 2.3 Curing agents for epoxies - comparison summary. Source Air Products (Chemicals) pic, Clayton, Manchester, UK.

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