Patent GB-1065504-A (GB)
Title: Coated article
IPC: C08J7/044
Filed: 1964-10-05
Abstract: Stereoregular polypropylene articles e.g. fibres, yarns, fabrics, films or moulded articles, ahving insolubilised thereon a coating of a homopolymer of ethylene oxide or a copolymer of ethylene oxide with another lower alkylene oxide, examples of which are given, wherein said copolymer contains at least 40% by weight of ethylene oxide, are characterised in that the coating is insolubilised by cross-linking with an azido cross-linking agent. The coating may be formed by treating the articles with an ethylene oxide polymer or copolymer and with an azido cross-linking agent followed by cross-linking and insolubilisation of the polymer or copolymer coating by the action of heat e.g. by heating to a temperature between 70 DEG C. and the melting point of polypropylene, or radiation e.g. of wave length between 0.01  and 7600 .  The azido cross-linking agent may be an azido formate having the formula <FORM:1065504/D1-D2/1> where X is at least 1 and R is an organic radical inert to the cross-linking reaction containing at least one carbon atom per azido formate group; or an aromatic polyazide of formula <FORM:1065504/D1-D2/2> where R is an aromatic group inert to the cross-linking reaction and X is an integer from 2 to 200; examples are given.  An amount of azido cross-linking agent corresponding to 0.1 to 20% by wt. of ethylene oxide polymer or copolymer may be used.  The amount of ethylene oxide polymer or copolymer used may correspond to 0.01 to 25% by wt. of the polypropylene, or may correspond to a surface layer thickness of from one molecule to 3 mils. e.g. 20  to 1 mil.  The coating may be applied from a solution dispersion, emulsion or melt, by dipping, spraying, padding, painting, roll or doctor blade.ALSO:Stereoregular polypropylene articles e.g. fibres, yarns, fabrics, films or moulded articles, having insolubilised thereon a coating of a homopolymer of ethylene oxide or a copolymer of ethylene oxide with another lower alkylene oxide, examples of which are given, wherein said copolymer contains at least 40% by weight of ethylene oxide, are characterised in that the coating is insolubilised by cross-linking with an azido cross-linking agent. The coating may be formed by treating the articles with an ethylene oxide polymer or copolymer and with an azido cross-linking agent followed by cross-linking and insolubilisation of the polymer or copolymer coating by the action of heat e.g. by heating to a temperature between 70 DEG C and the melting point of polypropyelne, or radiation e.g. of wave length between 0.01 A DEG  and 7600 A DEG .  The azido cross-linking agent may be an azido formate having the formula: <FORM:1065504/B1-B2/1> where X is at least 1 and R is an organic radical inert to the cross-linking reaction containing at least one carbon atom per azido formate group; or an aromatic polyazide of formula: R (N3) X where R is an aromatic group inert to the cross-linking reaction and X is an integer from 2 to 200; examples are given.  An amount of azido cross-linking agent corresponding to 0.1 to 20% by wt. of ethylene oxide polymer or copolymer may be used.  The amount of ethylene oxide polymer or copolymer used may correspond to 0.01 to 25% by wt. of the polypropylene, or may correspond to a surface layer thickness of from one molecule to 3 mils. e.g. 20 A DEG  to 1 mil.  The coating may be applied from a solution dispersion, emulsion or melt, by dipping, spraying, padding, painting, roll or doctor blade.