Patent GB-1198391-A (GB)
Title: Microporous Sheet Structures
Inventor: KONIG KLAUS
IPC: C08J9/28
Filed: 1968-05-10
Abstract: 1,198,391. Polyurethane laminate; polyurethane films. FARBENFABRIKEN BAYER A.G. 10 May, 1968 [12 May, 1967], No. 22229/68. Headings B5B and B5N. [Also in Divisions B2 and C3] Microporous sheet structures are prepared from (i) a high M.W. prepolymer having at least 2 active hydrogen atoms on at least 2 basic nitrogen atoms and (ii) a high M.W. prepolymer containing at least 2 isocyanate groups and/or a low M.W. monomeric polyisocyanate by dispersing a non-solvent for the polymer to be produced in either of (i) or (ii) and then mixing the dispersion with (ii) or (i) respectively, or by mixing (i) and (ii) and dispersing the product in the non-solvent, and applying the reaction mixture obtained to supports so that a sheet structure is formed before the polyaddition is completed, the non-solvent and any solvents present being removed during and/or after completion of the polyaddition. The prepolymers (i) and/or (ii) may be dispersed or dissolved in a solvent or solvent mixture and may contain a further quantity of non-solvent. The prepolymer (i) may be mixed with low molecular weight polyamines or hydrazines. The prepolyrners (i) may be prepared by reacting prepolymers containing NCO groups with an excess of polyamines or hydrazides in solution, or with sulphonic acid, or with formic acid followed by saponfication, or with secondary or tertiary carbinols followed by decomposition into the corresponding amines, by reacting high M.W. hydroxyl compounds with ammonia or amines in the presence of catalysts with application of pressure and heating, by reacting high M.W. hydroxyl components with acrylonitrile followed by catalytic hydrogenation, by reacting high M.W. hydroxyl components with aminomethyl-5,6-dihydro-(4H) pyran derivatives, by addition of nitro-aryl isocyanates to high MW hydroxyl compounds or by reacting high M.W. hydroxyl compounds with diphenyl carbonate followed by reaction with hydrazine. The prepolymers (ii) may be prepared by reaction of organic polyisocyanate with e.g. polyethers, polyesters and polyester amides. Suitable non solvents are aliphatic hydrocarbons, glycols, alohols, ethers and especially water. Polyaddition is completed on the supports preferably at temperatures above 50 C. Complete removal of the solvent and non- solvent is effected, e.g. by evaporation, optionally under a vacuum, or by flushing out from the resulting sheet structures It is preferred to mix the reaction components in a mixing apparatus which contains a chamber that is free from a gaseous phase. Emulsifiers, fillers, pigments, high M.W. polymers and cross-linking agents may be added to the reaction mixture. Coated products are obtained by applying the reaction components to porous supports such as knitted fabrics, woven fabrics, fleeces, felts and split leather. Films may be produced by stripping the resulting microporous sheets from non-porous supports such as glass, metal, paper or woven fabric coated with perfluoropolyethylene, and these films may be adhered to substrates such as wood, split leather, cardboard, paper and woven or unwoven textile sheets.