| 摘要 |
A copy sheet has on one side a coating comprising a continuous phase of coating material and two reagents dispersed therein. These two reagents can be brought together by writing pressure, and can then enter into a colour reaction. Each of them is present in the continuous phase in an emulsified form, stabilized by a separate protective colloid. In the example, a copolymer of vinyl chloride and vinyl isobutyl ether and a phthalate plasticizer are dissolved in butyl acetate; ferric chloride, casein and oxalic acid are dissolved in water; potassium cyanide and casein are dissolved in water; the first solution is divided into halves, and the second and third solutions each emulsified in one half; the two emulsions are then mixed and applied to paper or other sheets or films. |
