Manufacture paper carrier bags efficiently with cold glue

Paper carrier bags can be produced efficiently and reliably using Robatech electric cold-glue application heads. High switching frequencies and good adhesive guidance enable coating with precise cut-off and exact edge definition. The advantage: Savings of kraft paper and no excessively protruding paper edges on the inside of the bag. With just two application head types – Presto and Sempre – you can apply coatings in all application widths and beads for reliably glue flat handles and paper carrier bags.

Consumers around the world are demanding packaging and converting solutions that are easily recyclable. Carrying bags made of plastic or plasticized materials are therefore made more often from paper. This trend, known as paperization, presents many companies with new challenges: part of the production process has to be redesigned.

For this reason, Robatech offers an adhesive process with cold glue application for the production of paper carrier bags. Cold glue penetrates the paper and bonds it irreversibly and reliably.

The production of paper carrier bags and flat handles with cold glue basically requires the following stations in the adhesive application:

Coating on an endless strip of paper for the production of flat handles

A coating head continuously applies cold glue to an endless strip of paper. The paper strip is folded, glued again by another coating head, and folded again and then cut. The cut paper strips are then folded into a U-shape. The flat handle is finished.
Bead application on kraft paper for fixing the flat handles

Jetting heads apply cold glue beads to kraft paper. Subsequently, the flat handles are placed on the kraft paper and pressed on slightly. The next step is to cut the kraft paper.
Coating on continuous paper web for placing the flat handles

Two coating heads intermittently apply cold glue to the continuous paper web for the paper carrier bags. The kraft paper with the handles is applied precisely to these adhesive coatings.
Adhesive application on the longitudinal side of the continuous paper web

Depending on the requirements, an adhesive bead or a coating is applied longitudinally to the continuous paper. The web is then folded longitudinally so that a closed paper tube is formed. A transverse cut is made and the bottom is folded.
Bead application on bottom flap

The bottom flap is glued with several beads. Applying light pressure, the bottom is finally closed. The paper bag is finished.

Presto in the multi-head version achieves a maximum application width of up to 165 mm. Ideal for the coating on the paper web to apply the kraft paper with handles. The special feature about Presto: the precise cut-off and the exact edge definition of the application eliminate the risk of adhesive spreading beyond the edge of the kraft paper and sticking the web. Presto thus eliminates the need to add a safety margin. This saves kraft paper and improves quality, because the paper edges on the inside of the bag do not protrude excessively. The application width of the multiple head Presto is also varied by means of a mask.

The handles and bottom of a paper carrier bag must hold particularly well. A reliable bead application is therefore of decisive importance for stability. In plain language, this means: precise start and cut-off as well as exact adhesive application quantity. Criteria that the Sempre electric jetting head fulfils as a matter of course. The amount of adhesive applied is fine-tuned by means of a material pressure regulator and the stroke adjustment integrated in the application head. Optionally, a sensor monitors deviations, presence, placement and volume of the adhesive bead.

Easy system integration

Control of the application heads via PLC up to max. 15 bar or via control unit up to max. 30 bar adhesive pressure.
Compact, narrow design of the application heads