This invention relates to a new foam product suitable for use as insulation in the building industry. Involved are resin systems which have been previously investigated but not used together in the system disclosed herein. One of these systems is based upon the urethane formation reaction wherein an isocyanate is reacted with a compound containing hydroxyl groups. A second reaction involved is the trimerization of isocyanates, a reaction used in the production of polyisocyanurate products. Finally, a third reaction involved is the curing of an unsaturated polyester resin with a cross-linking vinyl monomer in the presence of a free radical catalyst. The present invention combines these reactions in a manner not previously utilized by mixing two or more reactant streams in the manner to be fully described hereinafter.
One example of such prior operation is Graham et al., U.S. Pat. No. 3,860,537 (1975) where a stepwise reaction is used. In the system disclosed in that patent, a mixture of polyurethane precursors comprising a polyol and a polyisocyanate is mixed with polyester resin precursors comprising an unsaturated polyester and an unsaturated monomer. These mixtures of precursors are mixed and partially cured so that the precursors in the mixture react such that the mixture of the polyfunctional compound and the ethylenically unsaturated polyester are substantially reacted with the polyisocyanate, and the ethylenically unsaturated polyester and the unsaturated monomer are substantially uncopolymerized. The patent describes subsequently carrying out the second polymerization. In the system disclosed herein, all of the reactions take place at substantially the same time.
Additional work in the field is represented by Hutchinsen et al., U.S. Pat. No. 3,886,229 (1975) although this patent does not disclose foam products. In the system of Hutchinson et al., as in Graham et al., a polymeric product is formed by mixing precursors of a polyurethane comprising at least one diisocyanate and at least one difunctional compound with a second component comprising precursors of a cured polyester resin comprising an unsaturated polyester and at least one monomer copolymerizable with the unsaturated groups in the polyester. It will be apparent from the description of the invention disclosed herein that different preliminary mixtures are made prior to the mixing and reaction of the various ingredients.
In view of the above, it is an object of this invention to provide a new system for the production of a new insulating foam board.
A further object of this invention is to provide an insulating foam board based on an unsaturated polyester resin, which is capable of high filler loadings.
A further object of the invention is to provide an insulation foam board having a flame spread less than 50, preferably less than 25, and smoke generation less than 450 in the ASTM E84 test.
Other objects and advantages of the present invention will be apparent to those skilled in the art upon reading this disclosure.