Patent GB-1159195-A (GB)
Title: A Method for the Production of Iridescence on Synthetic Polymeric Surfaces
Inventor: STANLEY ROBERT HOLROYD
IPC: C09C1/00
Filed: 1967-04-18
Abstract: 1,159,195. Iridescent coating. BRITISH TITAN PRODUCTS CO. Ltd. 15 March. 1968 [18 April, 1967], No. 17709/67. Heading B2E. [Also in Division Dl] Iridescent synthetic polymeric surfaces are produced by applying to the surface as a film of variable thickness a titanium compound having the formula TiX 4  in which X represents a halogen atom or -OR in which R is an organic radical and wherein two or more X groups can be the same or different, the thickness of the film deposited being adequate to produce iridescence within the visual spectrum and subsequent to application of the film ageing the so-treated surface at above 85C and below the melting point or decomposition point of the surface. Synthetic polymeric materials which can be treated are polyolefines or copolymers of two or more olefines, polyvinyl or polyvinylidene compounds, polyacrylates and polyalkyl acrylates and copolymers of acrylates or alkyl acrylates, polyesters such as cellulosic esters, polycarbonates, polyvinyl alcohol esters and polyethylene condensation esters. Typical polymers are polyethylene, copolymers of ethylene and propylene, polyvinyl chloride polyvinylidene chloride, polymethyl methacrylate, polyethyl acrylate and cellulosic esters, and polyethylene terephthalate. The titanium compounds may be titanium tetrahalides such as the bromide or iodide or tetrachloride, or alkyl titanates e.g. tetra alkyl titanates and alkoxy titanium halides particularly dialkoxy titanium dichlorides and alkanolamino titanates such as triethylanolamine titanate. The titanium compound may be applied by moving the surface longitudinally under one or more orifices above the surface through which the titanium compound is introduced, or the compound may be applied to a jet or by means of a suitable printing technique either as a neat liquid or in solution. Alternatively the synthetic polymeric material can be dipped into a solution of the compound. The compound may be introduced through a jet by means of a carrier gas in which it is dispersed. The orifices may be stationary to produce longitudinal bands of iridescence, or may be moved across the surface as it moves beneath them to produce transverse bands of iridescence. The flow of titanium compound may be continuous or intermittent. Alternatively the surface may be stationary and the orifices moved. The surface may be treated prior to treatment with the titanium compound for example with an electric corona discharge or with a synthetic resin composition, generally a thermosettable resin composition e.g. an hydroxy acrylic resin curable with an amine or with a melamine/formaldehyde resin, or phenol/formaldehyde, resorcinol/formaldehyde, urea/aldehyde and epoxy resins, polyurethanes. The surface may be buffed after treatment. The iridescent polymer films can be used for the production of woven fabrics and to manufacture articles such as eye glass or spectacle frames e.g. by laminating an iridescent film with one or more support sheets of a plastics material and cutting the frame from the laminate. In the drawing, the apparatus comprises a horizontal glass tube 1 provided with a metal end plate 2, 3 at each end, each plate having a horizontal slit 4. Two similarly slotted divider plates 5, 6 are positioned along the tube 1. Asbestos tape 7 carrying an electrical heating element 8 is wound about the outside of the first part of the tube. A glass conduit 11 passes through a hole in the top of the tube and is connected to a supply of dry nitrogen containing titanium tetrachloride vapour. The end plate 2 is also provided with an inlet port 12 supplied to the tube of dry nitrogen only for purging air from the apparatus and the other end plate 3 carries an outlet tube 13 to exhaust excess vapour from a tube 1. Two thermometers 14 and 15 are also fitted. In Example 1 a strip of polyethylene terphthalate film was dipped into a solution comprising hydroxyacrylic resin, butylated' melamine/formaldehyde resin, xylene and butanol, allowed to drain and then passed through the apparatus maintained at 180C. The strip 20 was then fed from reel 18 between two plates 16, 17 faced with baize into tube 1 through slit 4, through tube 1 and out of the slit 4 in the end plate 3 and to a second reel. The tube was maintained at 180C and a dry nitrogen fed into the tube via inlet 12. Nitrogen saturated' with liquid' titanium tetrachloride was continuously supplied to the glass conduit 11.  When the strip 20 had been treated excess titanium tetrachloride was removed through outlet 13 and the strip allowed to cool whilst moving through the last two feet of the apparatus prior to being wound in reel 19. The cool strip was then heated for 70 minutes at 180C. The resulting iridescent strip was found to be able to withstand boiling-in 0.50/) soap solution for up to one hour without losing its colour. In the other examples; (2) polyethylene film and nitro-cellulose were similarly treated as in (1); (3) polyethylene terephthalate films treated with the acrylic copolymer solution as described in (I) are treated by dipping into various solutions of titanium compounds such as a solution of titanium tetrachloride in toluene, diisopropoxy titanium dichloride in isopropanol, triethanolamine titanate is isopropanol, polybutyl titanate in heptane, polypropyl titanate is isopropyl, butyl titanate in butanol; (4) polyethylene terephthalate film is treated with a polyurethane priming composition before treatment with titanium tetrachloride vapour as in (1); (5) the process of (I) is repeated except that the surface was subjected to an electric corona discharge instead of treatment with the acrylic copolymer solution and heating of the treated surface prior to contacted titanium chloride was omitted.