Abstract: A composition having beneficial utility for curing polyurethane prepolymers can be made by (1) forming a mixture of (A) an inert organic liquid and (B) particles of a complex of 4,4'-methylenedianiline and a salt, said mixture containing a small amount of free methylenedianiline, (2) adding to said mixture a small amount of an aromatic monocarbodiimide and (3) allowing said carbodiimide to react with the free methylenedianiline.

Abstract: A heat-activatable polyurethane powder composition is prepared which contains both epoxy and amino end groups, the distribution of which is determined by the order in which the reactants are brought together. When the powder is deposited on a substrate and heated above its melting point, the epoxy groups react with the active hydrogens available from the amino groups, resulting in the formation of a high molecular weight polyurethane film.

Abstract: A segmented, branched thermoplastic copolyester containing intralinear long chain and short chain ester units is produced at a high rate if such production takes place in the presence of a critical amount of a branching agent, said branching agent having the general formula (HO).sub.a X (COOH).sub.b and having a molecular weight of about 92 to 5000, wherein X is a polyfunctional radical, a = 0-6, b = 0-4 and a + b = 3-6.

Abstract: Segmented thermoplastic copolyester elastomers containing recurring polymeric long chain ester units derived from dimer acid and low molecular weight glycols and short chain ester units derived from dicarboxylic acids and low molecular weight glycols. At least 70% of the dicarboxylic acid used is terephthalic acid and at least 70% of the low molecular weight glycol is 1,4-butanediol. The short chain ester units constitute about 25-95% by weight of the polymer. Such copolyesters rapidly harden from the molten state and have outstanding resistance toward heat aging and photodegradation.

Abstract: A heat-activatable polyurethane powder is prepared which contains about stoichiometric amounts of both blocked --NCO groups and active hydrogen-containing groups, the distribution of which is determined by the order in which the reactants are brought together. Typically an emulsified polymeric glycol (which may be admixed with more or less low molecular weight diol) reacts with a limited excess of diisocyanate to produce a dispersion of beads of --NCO-terminated polyurethane prepolymer; these in turn are reacted first with enough phenol or other monofunctional blocking agent to tie up about half of the free --NCO groups and secondly with one mole of a diamine or other difunctional active hydrogen compound per equivalent of the other half of the --NCO groups. When the resulting powder is coated upon a substrate and heated, the blocked --NCO groups are regenerated and thereupon they react with the active hydrogens available, resulting in the formation of a high molecular weight polyurethane film.