| 摘要 |
<p>Permanent colour change obtained by deformation of a flexible softener-free film. N1-. Is achieved by using for the film an emulsion graft copolymer containing vinyl chloride and 5-30 weight % (on the total product), of an elastomer based on butadiene and/or isoprene, higher dienes or halo-substituted dienes, and vinyl monomers, preferably styrene acrylonitrile maleic esters and/or (meth)acrylic ester. The colour change (white fracture) is obtained by deforming the film to above the elastic limit, particularly by deforming the film in a label-stamping machine. The film is transparent. It may be thin, and is flexible enough to be applied to uneven surfaces, to which it will adhere for long periods. The white fracture is stable at up to above 80 degrees C. The process can be applied to decorative and packing materials as well as to labels.</p> |
