Controlled deposition of melt-adhesive on plastics bag bottoms - by applying a U-shaped track of adhesive in specified position

摘要

In a method of applying meld-adhesive onto bottoms of plastics bags or carrier bags made of webs that are laid out to form a tube and are to be glued in machine direction, in such a way that the adhesive is applied in a conformity with the shape of the bag bottom, by applying the adhesive, as a melt, onto blocks made of a matl. whose adhesion to the liq. adhesive is good but whose wettability w.r.t. the adhesive is appreciably lower than the wettability of the adhesive w.r.t. the matl. to be flued; and then contacting the adhesive-coated block with the tubular film, as in parent patent, the melt-adhesive is applied, in known manner, onto the still-open section of plastics film, provided with pre-folded flaps, from which it is intended to form a bag bottom, in a U-shaped track so that the leg of the U run parallel to the longitudinal direction of the tubular film and the arc connecting the legs of the U lies on the inside of the bottom closure forming the covering flap. The track of the adhesive applied will conform accurately with the shape of the bottom to be formed.