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Reply devices, such as tear-off envelopes or foldable postcards with a pre-glued edge, make it easy for customers to return order forms or information requests. Remoistenable glue, applied as part of the printing process, is a cost-effective technique for incorporating such a feature in your direct-mail campaign.
Until 20 years ago, adding pre-glued direct response devices was hampered by the special difficulties of using cold water-soluble glues. Today, newer printing technology and the use of extruded, hot melt, remoistenable glues allow sheet-fed and non-heatset web printers to cost-effectively produce top quality direct reply mailers even for short runs.
Cold Remoistenable Glue
Older water-soluble glues are applied with either a wheel or blanket. Different application pads control the size and direction of the glue strip. However, cold glue requires hot drying, which can create paper curl. Additionally, the start of the glue strip tends to be thicker, which results in non-uniform drying or the possibility that adjacent pieces will adhere to one another.
Extruded Hot Remoistenable Glue
Hot melt extruded glue avoids these disadvantages of cold glue. Since a hot glue process does not add moisture, ragged looking edges or paper curl are avoided. Computer control and motion detection enable more precise control over glue strip appearance and placement on the paper than cold glue can. Additionally, hot glue presents a smooth, shiny, professional appearance that cold glue cannot match.
The hot melt extrusion process has a potential disadvantage however. It only applies glue in parallel lines, so special patterns, such as a ‘U’, require more than one pass through the machine.
Tips for a Successful Remoistenable Glue Run
Paper and Coatings
Remoistenable glue generally adheres well when moistened with both coated and uncoated paper stock of 60 lb. weight or greater. Uncoated paper usually uses more glue to compensate for paper porosity. Varnished paper may prevent good adhesion. When stock is flood-varnished, care should be taken to block or remove the varnish where a hot glue strip is to be placed.
Although remoistenable glue works well with most printed material, paper with 100 percent ink coverage can reduce its adhesion due to the heavy ink solids.
Water-soluble remoistenable glues should only be applied in a climate-controlled environment, especially in high humidity locations. Silica gel packets should be included in packaging as well.
When a job requires more than one glue strip, ensure that strips do not touch one another when packaging them. Glue strips should be staggered to avoid them adhering to each other during shipping.
Flatbed trimming of glued and folded runs should not be attempted. Such trimming requires very small lifts to avoid tearing, which hurts productivity, and the glue line creates an uneven profile that creates knife drag and an uneven cut. Furthermore, the cutting blades will dull very quickly if they cut through the hot melt glue line.
Leave It to the Experts
Bond Tech provides state-of-the-art hot glue technology so you can ensure your direct-mailers are of excellent quality. Professional looking response devices that are easy for customers to manage give you the best opportunity for a successful marketing campaign.
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