METHOD OF HARD POLYURETHAN PRODUCTION

The present invention relates to the obtention of a rigid polyurethane compound, cellular or micro-cellular, reinforced or not, having a density ranging from 0.20 to 1.30 g/cm3; the formation of this compound happens through the mixing of a resin composed of a mixture of polyether and polyester polyols aminated or not, having a molecular weight ranging from 100 to 5000, employed at 5 to 100 parts by weight; surfactant based on dimethylpolysiloxane, employed at 0.1 to 5 parts by weight; amine catalysts of the tetramethylethylenediamine and dimethylcyclohexylamine type employed at 0.1 to 6 parts by weight; fluorinated blowing agents, such as trichloromonofluoromethane, used at 0 to 50 parts by weight; a reinforcing agent such as milled, hammered fiberglass, rice husks, coffee husks or corn husks and polypropylene strands or mineral charges, used at 0 to 50 parts by weight; and a flame retarding agent such as diethyl N,N bis (2-hydroxyethyl) aminoethyl phosphonate of tri (B-chloro-isopropyl)phosphate, used at 5 to 30 parts by weight. An aromatic poly-isocyanate, which can be toluene diisocyanate (TDI) or diphenylmethane diisocyanate (MDI) employed at 90 to 150 parts by weight, is mixed with the resin in an appropriate machine and, when the mixture is injected in a mold having the shape of the part, that mixture acquires exactly the shape thereof, being finished in a few minutes. The utilization of this patent of invention is to replace steel in home appliances such as: panels, parts and doors of refrigerators and freezers, panels and parts of laundering machines, dish washers, clothes driers and microwave ovens.