| 摘要 |
1,209,243. Polyurethane foams. FARBENFABRIKEN BAYER A.G. 15 March, 1968 [15 March, 1967], No. 12806/68. Headings C3C and C3R. Polyurethane foams are prepared under compression in closed moulds by reacting therein at least one polyisocyanate and at least one reactive hydrogen-containing compound in the presence of up to 0À2 mol. of an organic solvent blowing agent per 100 grams of the reactive hydrogen-containing compound, such that the sum of the density, in grams/cm,<SP>3</SP>, of the foam produced without compression and the degree of compression employed during foaming in a closed mould is 1.45 to 8.15 and the product of said density and said degree of compression is from 0.2 to 1.2, the foam having a density which gradually decreases towards the centre thereof, where it is substantially at a minimum. Conventional polyisocyanates, reactive hydrogen containing compounds, such as polyethers and polyesters, blowing agents (other than water), catalysts and stabilizers are used in the production of the foams. Numerous fillers may be added to the foam-forming mixtures, a preferred one being cut glass fibre. |
