Abstract: Polyurethane-urea elastomers with improved temperature characteristics, in particular improved low temperature properties, good mechanical properties over a large temperature range and excellent resistance to hydrolysis, are obtained by reacting(A) a prepolymer, possessing cycloaliphatic NCO groups, which has been prepared from essentially difunctional polyhydroxy compounds and organic diisocyanates possessing at least one NCO group bonded to a cycloaliphatic structure, these reactants being used so as to give a ratio of total hydroxyl: NCO groups of from 1:1.2 to 1:10, with(B) 3,3',5,5'-tetramethyl-4,4'-diamino-diphenylmethane, A and B being reacted in the molar ratio of from 1:0.8 to 1:1.2.

Abstract: Hard, rigid, non-elastomeric, non-cellular polyurethane compositions manufactured by reacting a liquid hydroxylic polyether having an OH equivalent weight of from 50 to 250, a monofunctional hydroxylic polyether having a molecular weight of from 150 to 10,000 and devoid of further functional groups which react with isocyanates, and an organic polyisocyanate, with or without catalysts, auxiliaries and additives.

Abstract: Polyurethane elastomers of improved heat stability are made by a process in which a polyisocyanate is reacted with a polyol of high molecular weight with an OH:NCO ratio of 1:0.66 to 1:0.85, and the resulting adduct is later reacted with an excess of symmetrical diisocyanate and a diol as chain extender.

Abstract: The invention concerns a process for making heat-resistant polyurethane elastomers from substantially linear polyhydroxyl compounds of high molecular weight, polyisocyanates, chain extenders, and, if desired, catalysts and additives, in which the polyhydroxyl compound is reacted with diisocyanate material in amounts to give an OH:NCO ratio of 1:1.10 to 1:2 and produce an adduct, and the adduct is subsequently reacted with symmetrical aromatic diisocyanate and a diol as chain extender (preferably a linear diol containing 2,4 or 6 carbon atoms) to obtain a crystalline or crystallizable diurethane or polyurethane of good heat resistance.

Abstract: Fluid photo-crosslinkable composition consisting essentially of a photo-initiator and a mixture ofA. a polyurethane obtained by reacting a hydroxyl-containing saturated aliphatic polyester with a polyisocyanate and a monoacrylate or monomethacrylate of a diol, andB. an N-vinyl lactam optionally in admixture with other monomers.These compositions are suitable for the production of high-quality relief printing plates and have a short processing time.

Abstract: Laminates for the production of relief plates for flexographic printing, by imagewise exposure and washing out with a developer solution have, on a base optionally provided with an elastomeric layer, a photo-crosslinkable layer containing a photoinitiator and consisting of a polyurethane elastomer which has been prepared in a special manner from an aliphatic saturated polyesterglycol, an aliphatic diisocyanate, but-1-ene-3,4-diol and, if desired, another diol and which has a Shore A hardness of 30 to 90.degree. in the photo-crosslinked state, the elastomer being optionally mixed with a photo-crosslinked monomer.