| 摘要 |
654,664. Wrapping. WINGFOOT CORPORATION. Aug. 20, 1947, No. 23107. Convention date, Feb. 10. [Class 94(i)] [Also in Group VIII] A seal is formed between the surfaces of heat-sealable film wrapping material by treating with a sealing agent a part of the area of at least one of the surfaces while leaving an adjacent area of the surface untreated, and pressing the surfaces together and heating them over treated and untreated areas to a temperature below that at which the untreated area becomes tacky but sufficient to render the treated area tacky, the sealing agent being non-volatile at the said temperature but being dissolved into the surface of the film material by the treatment, whereby the treated area becomes tacky and the surfaces are united over the treated area only. A wrapped package may be sealed by sliding the package over a hot plate, one entire side of the package being heated although the seal is formed from only a small portion of the wrapper on this side of the package. The film material may be rubber hydrochloride and the sealing agent dibutyl phthalate or a mixture of 20 per cent dibutyl phthalate and 80 per cent triglycol dichloride by volume. Other film materials mentioned are polythene and a vinyl copolymer. Specification 451,573, [Group VIII], is referred to. |
