Patent GB-841272-A (GB)
Title: Manufacture of flexible cellular materials
IPC: C08J9/00
Filed: 1958-06-26
Abstract: In manufacturing a flexible cellular product from the reaction of a liquid mixture comprising water, an organic polyisocyanate or mixtures of polyisocyanates and an active-hydrogencontaining polymeric material, the reaction is conducted while the mixture contains air, nitrogen or oxygen present in an amount from 0,01 to 0,03 cubic centimetres (measured at atmospheric pressure) per 100 grams of the polymeric material, and the mixture is formed and set in the presence of the gas.  The gas may be introduced into the liquid mixture by mixing the gas with the active-hydrogen-containing polymeric material, by mixing the gas with a liquid prepolymer formed from the polymeric material and polyisocyanate, or by mixing the gas directly with the liquid mixture.  As active-hydrogen-containing polymeric material, polyesters, polyester amides or hydroxyl-terminated polyethers having an average molecular weight of 1,000-5,000 and an acid number not greater than 5 are preferably employed.  In examples, a first mixture was made from 50 parts by weight of a polyester, prepared from 1,1 mols of a mixture of 80 mol per cent ethylene glycol and 20 mol per cent propylene glycol, and 1,0 mol adipic acid and having an acid number of 2,3 and an average molecular weight of 1900 and 25,8 parts 2,4-tolylene diisocyanate.  A second mixture was made containing 50 parts by weight of the same polyester, 0,9 part of water and 1,0 part of a butyraldehyde/butylamine condensation product which functioned as a catalyst.  Both mixtures were heated to 140 DEG F. and then mixed in the ratio of 1,46 parts of the first mixture to 1,0 parts of the second.  0,02 c.c. per 100 grams of polyester of air, nitrogen or oxygen were metered into successive portions of the blended reaction mixture which was then poured into a mould where foaming took place; in each case the temperature increased from 140 DEG F. to more than 160 DEG F. whereas in control experiments using carbon dioxide or no added gas no temperature rise occurred.  The moulded samples were finally permitted to cure at room temperature for thirty minutes and removed from the mould.  The products had small, uniform pores.  In comparative examples using excess of gas bubbles of occluded gas remained in the finished product.ALSO:In manufacturing a flexible cellular product from the reaction of a liquid mixture comprising water, an organic polyisocyanate or mixtures of polyisocyanates and an active-hydrogen-containing polymeric material, the reaction is conducted while the mixture contains air, nitrogen or oxygen present in an amount from 0,01 to 0,03 cubic centimetres (measured at atmospheric pressure) per 100 grams of the polymeric material, and the mixture is formed and set in the presence of the gas.  The gas may be introduced into the liquid mixture by mixing the gas with the active-hydrogen-containing polymeric material, by mixing the gas with a liquid prepolymer formed from the polymeric material and polyisocyanate, or by mixing the gas directly with the liquid mixture.  As active-hydrogen-containing polymeric material, polyesters, polyesteramides or hydroxyl-terminated polyethers having an average molecular weight of 1,000-5,000 and an acid number not greater than 5 are preferably employed.  In examples, a first mixture was made from 50 parts by weight of a polyester, prepared from 1,1 mols of a mixture of 80 mol per cent ethylene glycol and 20 mol per cent propylene glycol, and 1,0 mol adipic acid, and having an acid number of 2,3 and an average molecular weight of 1900, and 25,8 parts 2,4-tolylene diisocyanate.  A second mixture was made containing 50 parts by weight of the same polyester, 0,9 part of water and 1,0 part of a butyraldehyde/butylamine condensation product which functioned as a catalyst.  Both mixtures were heated to 140 DEG F and then mixed in the ratio of 1,46 parts of the first mixture to 1,0 part of the second.  0,02 c.c. per 100 grams of polyester of air, nitrogen or oxygen were metered into successive portions of the blended reaction mixture which was then poured into a mould where foaming took place; in each case the temperature increased from 140 DEG F to more than 160 DEG F whereas in control experiments using carbon dioxide or no added gas no temperature rise occurred.  The moulded samples were finally permitted to cure at room temperature for thirty minutes and removed from the mould.  The products had small, uniform pores.  In comparative examples using excess of gas bubbles of occluded gas remained in the finished product. Specifications 687,055, 694,982, 696,449, 731,071, 769,682 and U.S.A. Specifications 1,780,326, 1,780,334, 2,674,619, and 2,777,831 are referred to.