| 摘要 |
<p>A sheet material, for detaching, ethyleneoxide, contains a coating of a water-soluble salt reactive with ethylene oxide and an indicator which changes colour with increase in hydroxyl ions and optionally a humectant. The compositions may be incorporated in a binder and may be in roll form with a pressure-sensitive adhesive backing. The sheet material may be of paper or polymeric film and binders exemplified are polyvinylpyrrolidone/vinyl pyrrolidone copolymer with vinyl acetate with glycerine. Indicators exemplified are malachite, green oxalate, metacresol purple, bromthymol blue, alizarin yellow, phenolphthalein and thymolphthalein and cupric chloride and cobaltous chloride. Reactive salts include tin and aluminium chlorides, magnesium and lithium bromides, sodium phosphate, thiosulphate and acetate, potassium iodide and isothiocyanate and polydiethyl aminoethyl methacrylate methyl bromide quaternary salt. The sheets may be overprinted with a pattern thus providing a reference colour. U.S.A. Specification 2,940,591 is referred to.</p> |
