1. How to choose a rubber roller (net roller)? How much glue is appropriate?
Water-based glue has a small amount of glue, so it is very important to choose a suitable rubber roller. For water-based glues, the dimples on the upper roller should be shallow and the openings should be large so that the glue can contact the substrate with the maximum surface area. This results in a uniform coating, fast drying, good composite appearance and high peel strength. A suitable mesh roller is the premise to ensure the amount of glue and peel strength, and the user should adjust it according to the equipment conditions and compounding speed. Motorized engraving rollers from 180 lines/inch to 200 lines/inch are recommended. The pits are interconnected, and the pit depth is 32µ to 35µ. Always clean the rollers during use to prevent clogging, and re-chrome or engrave new cable rollers after a period of use.
The appropriate amount of glue is 1.6g/m2 to 2.4g/m2, and cannot be lower than 1.6g/m2, otherwise the peel strength cannot be guaranteed. Too much glue will affect the drying of the glue, affect the leveling of the glue on the surface of the film, and then affect the composite appearance and peel strength.
2. How to solve high-speed composite bubbles? Can a defoamer be added?
In order to catch up with production schedules and reduce costs, some manufacturers are now very fast, some reaching 160m/min or higher. For this compounding speed, water-based adhesives tend to generate more foam in the tank. If the production continues for several days, the foam will accumulate more and even overflow outside the tank. If you do not take certain measures at this time, it may lead to problems such as less glue, low strength, and white spots. The best solution is to put an even ink stick in a plastic jar for defoaming. At the same time, use recycled glue to ensure that there is not too much glue in the glue tank. Recycling plastic buckets should be used. If the foam in the plastic bucket cannot be eliminated after long-term use, a spare plastic bucket can be used to apply glue, and the foam should be replaced after foaming. The original plastic buckets were eliminated.
YH620S products already contain defoamer, generally do not need to add defoamer, too much defoamer will affect the surface properties of the glue, thereby affecting the composite appearance. The added defoamer does not mix well with the glue and also affects the appearance of the composite.
3. Can water-based plastics be diluted with water?
Most of the water based adhesives on the market are emulsion type. The principle is that high molecular polymers exist stably in water by means of emulsifiers. Actually, it is a metastable state. Many external forces will break the gel and lose it. influences. I do not recommend diluting the glue with water, because diluting with water will increase the surface tension of the glue, destabilize the glue, and cause delamination. In addition, dilution can alter the surface properties of the product, resulting in poor wetting and affecting the appearance of the composite.
4. When using water-based glue for compounding, some white spots appear, which will disappear after aging for a period of time. What is the reason? How to avoid this from happening?
Water-based adhesives generally have a water content of more than 50% and must be completely evaporated in a short time, requiring sufficient temperature and wind speed. There are two reasons for the white appearance of composite products. There are two reasons: first, insufficient glue; second, incomplete drying. White spots can disappear after a short period of ripening, indicating incomplete drying, as ripening can further help water evaporation; otherwise, the amount of glue is insufficient.
To avoid incomplete drying, it is necessary to adjust the drying tunnel temperature and air speed. Drying temperature can be set to 70°C~80°C~90°C
