Polyurethanes. IX. New Types of Highly Elastic Products: Vulcollans. Part 2

In the 6th Communication on the general subject of urethanes, it was shown that, in the presence of an excess of a diisocyanate, in particular naphthalene 1,5-diisocyanate, linear polyesters of adipic acid and simple glycols simultaneously lengthen and become converted into so-called polyester isocyanates, with the isocyanate groups as terminal groups of the chains. While this earlier work was concerned with the problem of cross-linking to form the synthetic elastomer, Vulcollan, with water as the agent, the work described in the present paper deals with other cross-linking agents, including glycols, aminoalcohols, diamines, and other bifunctional compounds. The mechanism of cross-linking is discussed for each of these cases, and it is shown that the chemical nature of the cross-linking agent has a decisive influence on the properties of the resulting Vulcollan product. The methods of preparation which are described point the way to new manufacturing processes, particularly the possibility of molding Vulcollan without having to use a solvent.