Heat sealed sack of flexible film comprising a relief valve
A heat sealed sack (1) of flexible film of weldable plastic for airtight packaging of foodstuff to be warmed before consuming it, has a valve (2) for releasing pressurized vapors and/or gases in form of an insert of localized detachment of seal surfaces at a point along a weld seam joining juxtaposed edges of said flexible film of weldable plastic. The insert of localized detachment is in the form of a sticker pre-applied at a precisely determined location on the inner surface of said flexible film, in an area of the film destined to be welded for sealing the sack. The sticker comprises a flexible film of weldable plastic having a surface treated to render it peelable and a layer of a pressure activated adhesive over said peelable surface of application of the sticker onto the inner surface of said flexible film of the sack, or a multilayer laminate comprising a flexible film of a peelable film, a layer of pressure activated adhesive on the surface of application onto the inner surface of said flexible film of the sack and a solvent free layer of a weldable laquer or a second flexible film of weldable plastic first film.
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Published patent application
Disclosure date: 10-02-2007
Publication date: 11-03-2010
Applicant: MASTERPACK S P A, IT
Inventor: BINDA VALERIO, IT
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