GB1088626A - Production of cellular materials - Google Patents

Abstract

Organic, cellular thermosetting material is prepared by (a) feeding into a mixing zone under pressure: (1) two components which interact exothermally to form a thermosetting resin, at least one component being a viscous, liquid, organic material, (2) a cellulating agent present in sufficient quantity to expand the thermosetting organic material to a cellular state having a density from 1 lb. per cu. ft. to 10 lb. per cu. ft., said cellulating agent being liquid under conditions equivalent to those existing in the foaming zone, but creating a gas concurrently with the reaction proceeding in the thermosetting resin, and (3) an inert gas which is substantially insoluble in the resin components and is present in sufficient quantity to maintain a pressure of from 10 p.s.i.g. to 150 p.s.i.g. in the mixing zone, (b) admixing the inert gas, cellulating agent and the two components, (c) passing the mixture through an aperture to a foaming zone, and (d) maintaining pressure and temperature conditions in said foaming zone which promote curing and foaming of the mixture. The two components are generally fed into the mixing zone at a combined rate of from 0.25 to 20 pounds per minute. The aperture preferably has a diameter of from 1/32 to 1/4 inch. Alternatively, a plurality of apertures, of combined cross-sectional area equivalent to that of a single aperture, may be used. The process is particularly adapted to depositing of the foaming material from the aperture on to a substrate, especially a vertical surface. The cellulating agent preferably has a boiling point of from 60 DEG to 200 DEG F., particularly a halohydrocarbon. Water producing carbon dioxide in situ may be used in the case of a polyurethane. Suitable thermosetting resins are polyurethanes, epoxy resins and unsaturated polyester resins. In the case of polyurethane the two components are a material containing reactive hydrogens, preferably a polyol, and a polyisocyanate; in the case of epoxy resins an epoxide and a curing agent for the epoxide, e.g. amines, carboxylic acids and anhydrides, and in the case of unsaturated polyester resins a blend of an unsaturated polyester and an a ,b -ethylenically unsaturated cross-linking monomer, e.g. styrene or vinyl toluene, and a catalyst system for cross-linking the two.ALSO:Surfaces, particularly vertical ones, are coated with organic, cellular thermosetting resin by (a) feeding into a mixing zone under pressure: (1) two components which interact exothermally to form a thermosetting resin, at least one component being a viscous, liquid, organic material, (2) a cellulating agent present in sufficient quantity to expand the thermosetting resin to a cellular state having a density from 1 lb. per cu. ft. to 10 lb. per cu. ft., said cellulating agent being liquid under conditions equivalent to those existing in the foaming zone, but creating a gas concurrently with the reaction proceeding in the thermosetting resin and (3) an inert gas which is substantially insoluble in the resin components and is present in sufficient-quantity to maintain a pressure of from 10 p.s.i.g. to 150 p.s.i.g. in the mixing zone, (b) admixing the inert gas, cellulating agent and the two components, (c) passing the mixture through an aperture on to the surface and (d) maintaining pressure and temperature conditions which promote curing and foaming of the mixture on the surface. The two components are generally fed into the mixing zone at a combined rate of from 0.25 to 20 pounds per minute. The aperture preferably has a diameter of from 1/32 to 1/4 inch. Alternatively, a plurality of apertures, of combined cross-sectional area equivalent to that of a single aperture, may be used. The foaming resin preferably has a density of from 20 to 70 lbs. per cu. ft. as it strikes the surface. Suitable thermosetting resins are polyurethanes, epoxy resins and unsaturated polyester resins.