Polyols and Requirements for Ambient Cure Foams

Abstract

Introduction flexible and semi-rigid urethane foam formulations which generate sufficient exotherm to quickly cure (5-15 minutes) molded foam have received considerable attention by the Urethane industry. Whether termed &dquo;cold cure&dquo; (1), &dquo;cold mold&dquo;, &dquo;ambient cure&dquo;, &dquo;quick strip&dquo; (2) or &dquo;high resiliency&dquo;, they have one ingredient in commona reactive polyol of relatively high molecular weight. Possible cost savings a simplified molding operation (1, 2, 3, 4) might afford added impetus to early development work. Further, the excellent resiliency, comfort (4) and fatigue resistance low density &dquo;ambient cure&dquo; (AC) foams offer are considered very desirable. It is now generally recognized quality molds are necessary for efficient operation and post cure may be necessary to attain suitable strength properties and/or full properties in a reasonable period of time. Rapid mold cycle times are a real advantage in any event. Several patents have issued on the AC process ( 5, 6, 7). The development of &dquo;integral skin&dquo; (IS) foams has also received considerable attention by the Urethane industry (1,2,3,8,9,10,11,12,13), and patents have issued on procedures and techniques for preparing such articles (14,15,16,17,18). The possibility of preparing a finished part in a single operation is very attractive. However, the tendency of urethane foams to discolor and the difficulty of getting low density, resilient IS foams have limited their utility. Generally, trichloromonofluoromethane is used to &dquo;blow&dquo; such foams and high concentrations of polyamines are added to provide urea linkages. Most IS formulations &dquo;ambient cure&dquo;, and, with the above exceptions, most IS foams are formulated like other AC foams.The manufacture of AC molded, and also slab stock foam, especially low density resilient foam, is predicted to increase sharply. The purpose of this report is to summarize the effect of formulation variables on AC foam properties with special attention given to the structure and composition of the polyether component. Although AC foams have the good properties previously mentioned, they do exhibit comparatively poor tear and elongation, high compression set and borderline humid aging resistance. In addition, the formulations are often This paper was originally presented at the SPI Cellular Plastics in Furniture and Home Furnishings Conference on September 14, 15 and 16, 1971. As a Conference Paper, it has not been subjected to the Journal's normal review procedures but is reprinted here as a service to our subscribers. surfactant sensitive (19) and display long tack free time in slab pours. Special attention will be given these problem areas, and, to do this efflciently, it will be assumed the general property trends observed in low density AC, semi-rigid AC and IS foams are correlatable. Formulation ComponentsA. Isocyanate-Toluene diisocyanate (TDI-usually a blend containing 80 to of the 2,4 and 20 % of the 2,6 isomers), crude TDIs of varying compos...

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