Resins, average molecular properties

Blends of piperylenes and amylenes (mixed 2-methyl-1-butene and 2-methyl-2-butene) or UOP propylene dimers can be adjusted to produce softening points of 0—100°C and weight average molecular weights of <1200 (32,33). Careful control of the diolefin/branched olefin ratio is the key to consistent resin properties (34). 

The property levels of cresol free solvent based poly(ester-imide) enamels are inferior to the cresylic products. In Table 3 the cresylic poly(ester-imide) varnish, solved in a mixture of cresol and Solvesso and the cresol free varnish 1, solved in a mixture of diethyleneglycol monomethyl and monoethyl ether plus some small amounts of Solvesso have the same resin composition. The cresylic product is superior. The reason is that the preparation of the cresol free resin was made using diethyleneglycol monomethyl ether as solvent in the synthesis, causing a lower average molecular weight of the polymer. The cresol free po-... 

The best known product made from aromatic polyester, however, is the blow-molded soda bottle, where the growth has been particularly dramatic during the past few years.This application accounts for 70-80% of the resin consumption and exploits the excellent barrier properties of the resin to carbon dioxide. It also requires the resin to be processed under conditions that would yield an amorphous (transparent) polymer with good gas barrier properties. The number-average molecular weight of the grade of resin used in bottles is about 80,000 (that used in fibers and films is about 45,000). 

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