Curing agents suppliers

Cycloaliphatic amines wide variety of modified products from major curing agent suppliers... 

All major curing agent suppliers listed above offer Polyamide curing agents. 

Commercial epoxy adhesives are composed primarily of an epoxy resin and a curing agent. Various additives and modifiers are added to the formulation to provide specific properties. Example trade names and suppliers of these ingredients are included in App. A. The curing agent may be incorporated into the resin to provide a single-component adhesive, or else it may be provided in a separate container to be mixed into the resin immediately prior to application. 

Curing agent Type equivalent weight at 25°C (DGEBA EEW 185) comments Supplier... 

Polyamides. Polyamides are formed by the condensation reaction of polyamines with dimeric fatty acids. They are available from a number of suppliers in a large variety of viscosities and molecular weights. Many products are available in the form of adducts which provide good compatibility with epoxy resins without the need for an induction period and give a better cure under adverse conditions compared with standard polyamides. Polyamide curing agents offer a number of desirable features, as follows (Dow Chemical Company, undated b) ... 

Resin I contains roughly equal amounts of diglycidyl ether of bisphenol A (DGEBA) and an epoxy cresol novolac. Sufficient dicyandiamide (DICY) as a curing agent is present such that the amine/epoxy ratio is 0.85. Monuron is present as an accelerator. The supplier s recommend standard cure is two hours at 127°C. Previous work (1 ) has shown that this cycle produces a fully cured system, as indicated by the disappearance of the epoxide absorbance band in the infrared spectrum. 

Resin II contains tetraglycidyl methylene dianiline (TGMDA) as the principal epoxide with small amounts of a cresol novolac and DGEBA. DICY as curing agent is present in an amount such that the amine epoxy ratio is 0.25. Diuron is the accelerator. The supplier s recommended standard cure is the same as for SP250. However, in this system approximately 20 percent of the epoxide remains unreacted following the cure cycle (1 ). Selected resin plates were subjected to additional cure at 170°C and 220°C. The samples post cured at 220 C for forty minutes showed no residual epoxide absorbance in the IR spectrum. 

Resin III is based upon DGEBA and an epoxy novolac in a one-to-two weight ratio. The curing agent is 3 percent boron trifluoride monoethylamine complex. The supplier s recommend cure cycle is 0.75 hour at 165 C followed by 4 hours post cure at 177 C. Some samples were cured for 24 hours at 80°C before post cure, while other samples were cured for the standard 0.75 hour at 165 C and subjected to different post cure times (2). There is still residual epoxide absorbance following initiaT 165°C cure. This absorbance decreases during post cure reaching zero after 4 hours. 

Curing of TTnsaturated Polyester Resins. The stages covered so far have been concerned only with that portion of the field which concerns the resin supplier.. His objective is to provide a clear, colorless, stable sirup to his consumers. The converters start with the sirup, add a curing agent. 

Curing Agent Application Types (Suppliers) Formulation and Ciel Times... 

The chemistry of this subject is complex and with the variety of epoxy resins and curing agents the reader is referred to references 3.3, 3.4 and 3.5 and should consult with materials suppliers for more detail. 

Major suppliers of epoxy curing agents include Ashland Chemical Inc. Ciba Geigy Corp. Dow Chemical Epic Resins Hexcel Corp. Shell Chemical Co. Thermoset Plastics Inc. Union Carbide and Uniroyal Chemical Co. 

There are numerous suppliers of epoxy curing agents. Some of the major producers are Air Products and Chemicals, Cognis, Degussa, DSM, Huntsman, and Resolution. 

Pre-vulcanized NR latex concentrate is a specialty latex that can provide small-scale manufacturing operators of latex products the convenience of ready-to-use latex compounds. All the necessary curing agents and accelerators have already been added by the latex supplier and it can be used directly, for example at the dipping plant. The rubber molecules within each latex particle of this latex have already been pre-crosslinked by the supplier. However, the particles remain separate and the latex remains fluid and stable. After dipping. 

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