| 摘要 |
PURPOSE:To suppress wrinkles of a cover material after it is heat sealed by embossing a part corresponding at least to the opening of a vessel with satin- or silk mesh-die having specific mesh or more. CONSTITUTION:An embossing to be conducted on a heat sealing cover material 1 is of satin- or silk mesh-die of 45 mesh or more. Such an embossing is conducted to impart rigidity to suppress wrinkles against a pressure reduction sucking force at the time of cooling after heat sealing. If it is less than 45 mesh, the seams of uneven part is excessively rough so that wrinkle preventing effect cannot be expected, and embossing except satin- or silk mesh-die such as cloth mesh-die cannot expect the preventing effect. The embossing of satin-die or silk mesh-die of 45 mesh or more is conducted on a part corresponding at least to the opening 20a of the vessel which is received directly by a sucking force in view of imparting the rigidity of the cover material against pressure reduction sucking force after heat sealing. It is preferable with good productivity to emboss a whole including the peripheral end of the cover material. |
