摘要:
This invention relates to crosslinkable polymeric compositions and a process for preparing them which show a low content of vinyl monomers, are suitable for the fabrication of composite materials, have good mechanical properties, and comprise: a liquid polyisocyanate; a polyol having a maximum functionality of 7 and an average molecular weight of from about 200 to about 10,000; an unsaturated polyester or a vinylester resin; a radical polymerization initiator stable at temperatures below 70.degree. C.; a decomposition promoter for the initiator; a trimerization catalyst for the isocyanate; and optionally, a mineral filler having dehydrating properties.
摘要:
A method for producing a novel silicone foam by reaction of a polyisocyanate with a silicone oligomer having a plurality of functional end groups with active hydrogens, optionally in the presence of fire-retardants, under foam forming conditions which creates a new silicone foam for use in items such as residential upholstered furniture industry, seat cushions and bedding etc., and specifically for use in applications that require, high resilience and fire-retardant properties such as aircraft and surface transportation seat cushioning, military and shipboard mattresses etc.
摘要:
Method of making a shell mold for casting molten metals or alloys involves forming a thermally collapsible, low density reaction injection molded (RIM) thermosetting polyurethane foam pattern having a shape corresponding to the casting to be made. The pattern is formulated to have an aggregate density (pattern outer skin and pattern cellular core) in the range of about 10 to 15 lbs/ft3 and a smooth continuous as-molded surface devoid of surface connected open cells, dimensional stability over a range of temperatures, and ready, ashless burnout from the shell mold formed thereon without cracking the shell mold. The pattern is free of organometallic catalysts that should not be present in the casting of aerospace superalloys, such as nickel and cobalt base superalloys and titanium. The pattern then is invested without the need for any surface polymer or other film or layer in a shell mold.
摘要:
Compounds (aminimides) of the class wherein a negatively charged nitrogen atom of an acylamide is directly bonded to a cationic nitrogen atom having one hydroxyethyl and two methyl substituents represent uniquely effective catalysts for the trimerization of the isocyanate radical. These aminimides are especially useful as catalysts for the preparation of rigid polyisocyanate-polyisocyanurate foams.