Cross-linked polyesters

Polyester blends Polyester carbonates Polyester containers Polyester-cotton blends Polyester, cross-linked Polyester diols... 

Catalyst selection, in unsaturated polyester cross-linking, 20 107-109 Catalyst Stabilization Technology (CST), 23 337... 

The traditional cross-linking technologies utilized in the coatings market range from hydroxyl functional binders (acrylics or polyesters) cross-linked with melamines (IK) or isocyanates (2K) to drying oils that cure through oxidation of unsaturation in the backbone, to epoxy resins cross-linked with amino resins (amido amines, amines, etc.). 

A simultaneous IPN of epoxy with unsaturated polyester, cross-linked using microwave radiation, has been reported (1). The radiation was intended to yield a more isotropic structure because of uniform heating also, it could reduce grafting reactions between the two networks and produce a more classical IPN structure. Unfortunately, the mechanical properties and morphology of the network were not reported. 

From these data it is apparent that the resin in the body filler is a styrenated diethylene glycol-isophthalic acid polyester cross-linked with maleic anhy-dride/fumaric acid and modified with adipic acid to give the resin flexibility. 

Polyesters flame readily, and sometimes vigorously, after ignition. Unsaturated polyesters, cross-linked with styrene, burn with heavy sooting. They can be flame-retarded mainly by reactive agents. 

While they are difficult to make, ship, store, and handle, the radicals they produce are very useful in vinyl free-radical polymerization, cure of unsaturated polyesters, cross-linking of thermoplastics, grafting, and compatibilization of polymer blends. 

Polyols are selected on the basis of cost, rate of esterification, stability during high temperature processing, functionality, and hydrolytic stability of their esters. The most widely used diol is NPG, and the most widely used triol is TMP. A comparison of results of testing films of coatings made with a series of polyesters from several polyols is given in Reference 167. Coatings based on CHDM polyesters cross-linked with MF resins showed the best hydrolytic stability. 

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