END-CRAFTING OF OLIGOESTERS BASED ON TEREPHTHALIC ACID AND LINEAR DIOLS FOR HIGH SOLIDS COATINGS

Oligomers derived from terephthalic acid and 1,6-hexanediol or 1,10-de canediol have been chemically modified through end-grafting with succi nic anhydride or trimellitic anhydride followed by glycidyl neodecanoa te. The grafted oligomers are paste-like semisolids or viscous liquids at room temperature. As the grafted oligomers are heated, their visco sity goes down to a minimum, then up to a maximum, and then down again . Combined DSC, crossed polarizing microscopy, and wide-angle x-ray di ffraction indicate that the grafted oligomers form crystalline domains dispersed in amorphous phase. The grafted oligomers are soluble in co mmon organic solvents, such as toluene, at lower concentrations (<14-5 1 wt %) and form stable dispersions at higher concentrations. High sol id coatings formulated with melamine or isocyanate resins gave glossy films with excellent combined hardness and impact resistance. (C) 1996 John Wiley & Sons, Inc.