Patent GB-1148551-A (GB)
Title: Process for applying finish compositions to synthetic microporous polymeric materials
Inventor: CRAVEN JAMES MILTON
IPC: C09D175/08
Filed: 1967-01-12
Abstract: 1,148,551. Polyurethane coating compositions; microporous polyurethanes; acrylic polymer coating compositions. E. I. DU PONT DE NEMOURS & CO. 12 Jan., 1967 [29 Dec., 1966], No. 1746/67. Headings C3C, C3P and C3R. [Also in Division B2] A coating composition comprises (a) a polyurethane consisting essentially of the reaction product of a bis-halo formate of a polyalkylene ether glycol having a molecular weight of more than 400, a bis-haloformate of a glycol having a molecular weight of less than 400 and an organic diamine and (b) a solvent which is (1) a mixture of an aromatic solvent and a hydroxyl terminated organic solvent which is a saturated aliphatic monohydric alcohol having from 1 to 6 carbon atoms or a glycol monoalkylether in which the alkyl group has from 1 to 4 carbon atoms, (2) an aralkyl alcohol, or (3) a halogenated organic liquid having a solubility parameter of from 9À1 to 10À7. The composition may have a polymer solids content of from 01 to 10% by weight. The composition may additionally contain from 0À5 to 10% by weight of the polymer of a silicone resin e.g. dimethylpolysiloxane, up to 50% by weight of the total polymer solids of polyvinyl butyral, and 10 to 50% by volume of one or more pigments. Examples of the components of the polyurethane and of the solvent are given. The chain extended polyurethane of the microporous sheet material may have a molecular weight of from 5000 to 300,000 formed by reacting an organic diisocyanate with an active hydrogen containing polyalkylene-ether glycol or a hydroxy terminated polyester to produce an isocyanate terminated polyurethane prepolymer which is chain extended with a compound having at least two amino nitrogen atoms, each having at least one reactive hydrogen attached thereto. Another coating composition comprises an acrylic polymer consisting essentially of from 1 to 6% by weight of units derived from an α-#-unsaturated monovinylidene carboxylic acid, units derived from a methacrylic acid ester, and units derived from an acrylic acid ester, the ester groups, which may be the same or different, being derived from saturated aliphatic monohydric primary alcohols containing from 1 to 12 carbon atoms. The carboxyl groups or the acrylic polymer may have been reacted with an alkylene imine of formula where R 1 , R 2 , R 3  and R 4  which may be the same or different are hydrogen or alkyl radicals having from 1 to 5 carbon atoms, the nitrogen content of the resulting polymer being from 0À5 to 1% by wt. The polymer may consist of a blend of (1) from 25 to 35% by wt. of a polymer comprising from 30 to 40% by wt. units derived from methyl methacrylate and from 70 to 60% by wt. units derived from ethyl acrylate; and (2) from 75 to 65% by wt. of a polymer comprising from 35 to 40% by wt. units derived from methyl methacrylate, from 50 to 60% by wt. units derived from ethyl acrylate and from 2 to 4% by wt. of units derived from methacrylic acid; and polymer (2) has been reacted with sufficient propylenimine to provide a nitrogen content of from 0À01 to 0À5% by wt. Examples of polymers are given. The polymer may have a tensile strength of at least 500 pounds per square inch and an elongation at break of at least 300%.