| 摘要 |
1,025,034. Marking packages. RESTELLO A.B. June 15, 1964 [June 26, 1963], No. 24699/64. Heading B8C. [Also in Divisions B5 and B6] In order to prevent a seal being opened and reclosed without leaving visible marks of having been opened, the seal is formed with an outer sealing zone 3, Fig. 2, defined at its inner edge by a sealing line 3, acting as a moisture bar to protect the contents 2 of a tube 1, and an inner part consisting of a pattern of letters or numerals. The seal may be at both ends of a tube of thermoplastic material, Fig. 2, or along four sides of two sheets for enclosing a flat object, Fig. 3. The pattern is formed by a heated sealing tool having the design in relief, and a dye ribbon may be used, or the pattern may be rendered more clearly visible by supplying the material with bismuth salts which change colour on heating. Alternatively, the material may have an outer layer which is more transparent than an inner layer, producing refraction phenomena at the sealing zones. A plastic layer of the wrapper may be laminated to a layer of paper or cardboard. The' tool may be a metal bar with a relief design, a wire arranged in the pattern or an insulating backing with a broken pattern of metal types heated by a high-frequency magnetic field. |
