Cold glue roll coaters and adhesive spreaders look like similar pieces of glue machinery. However, they have their own unique functions and operations. They are often used on the manufacturing production line for graphic arts, textiles, board products, and packaging. While they both deliver uniform coating, they serve different purposes.
Cold glue roll coaters transfer glue from a wheel to a substrate. They are ideal for use with smooth, flat surfaces, including sheeted components like paper and rigid board. The wheel is coated with glue and is usually traveling at the speed of the substrate. In addition to the roll coater, an additional roller above the glue wheel ensures that the substrate remains in contact with the glue wheel.
Roll coaters are ideal for use with low viscosity adhesives (water-based adhesives). They are typically made of rubber or chrome-plated steel. Because the roller is exposed, it does require regular cleaning to maintain top performance. A motor usually drives roll coaters at either constant or variable speed.
Adhesive spreaders extrude glue onto a substrate and flatten the glue with a nozzle. With manual adhesive spreaders, an operator draws the glue spreader nozzle over the substrate on a flat surface.The glue can be applied with a roller or directly from a nozzle/manifold. Automatic glue spreaders apply continuous coatings to continuous webs of material that are drawn under the nozzle. This application method delivers consistent glue output/coatings to webs moving under the nozzle with precise web tension.
Adhesive spreaders are ideal for use on substrates with coarse or rough surfaces like wood. The roller itself is made of rubber to accommodate the uneven surfaces. Spreaders typically receive glue through a pressurized “closed” system, which minimizes the amount of maintenance they require.