Roller-coat

Roller coating Roller-hearth furnace Roller nulls Roller printing Rollin film Rolling Roll nulls... 

Even more widely used are a variety of roller-coating techniques. In forward roller coating a controlled amount of paint is metered onto the surface of a rubber or gelatine roller rotating such that, at its point of contact with the sheet or web, roller and sheet are moving in the same (forward) direction. Even finer control of thin coatings is obtained if the paint is transferred from gravure cells onto the application roller. 

In the coating of continuous metal coils, reverse roller coating is often used. In this technique the web is moving counter to the application roller direction, so that the paint is partly wiped off by the moving coil. Shear leads to better flowout. Another type of reverse roller coating is used for the application of stiff paste fillers to chipboard. Application is by forward roller, but this is immediately followed by a reverse roller, which presses the filler into the board and doctors it smooth. 

A matter of considerable importance in the selection of an application method is its efficiency. Spray techniques are usually inefficient, since many droplets drift past the target and are lost. Even electrostatic spraying can waste as much as 35% of the paint. There is some loss of paint in most methods, but roller coating, curtain coating and electrodeposition are very efficient. Electrodeposition is also a very useful technique where corrosion resistance is important, since it applies a uniform coating over nearly all surfaces of even the most complex-shaped article. 

The back of the coil is simultaneously roller-coated at each station (if necessary) with a 10 /xm coat of polyester-melamine backer or a 3-5 xm coat of primer and 8-10/xm of backer. 

These coatings are applied by spray on more complex shapes, but on flat sheet or board roller coating is the preferred method, with curtain-coating used for thicker layers. 

Roller coating Raised surfaces can be painted without masking. Special effects like stripes. Roller applicator, either manual or automatic. Special paint feed system required for automatic work. Dryers... 

Water-base coatings for spray and roller coat application... 

The application processes are, for example, spraying, brushing, dipping, roller coating, electrostatic painting... 

Roll coating is widely used for uniform, whether flat or cylindrical, surfaces including fiber bundles. In a roll coating process, fibers are coated between two rollers, an applicator roller and a backup roller coating is fed continuously to the applicator roller by a feed roller which runs partially immersed in a coating bath and the backup roller pulls the fibers by rotating in opposite directions. Slow... 

Roller coating -for food packaging [FOOD PACKAGING] (Volll)... 

Poly(vinyl acetate) dry resins and ethylene-vinyl acetate (EVA) copolymers are used in solvent adhesives, which can be applied by total industrial techniques, e.g., brushing, knife-coating, roller-coating, spraying, or dipping... 

Waterborne Coatings, These coatings utilize either liquid or solid epoxy resins that have been modified to allow their use with water. They are usually in the form of emulsions, suspensions, dispersions, or water-dilutable resins that can be heat- or RT-cured. They are applied by convenient methods such as roller-coating, dipping, spray, or electro deposition. 

Poly(vinyl acetate) emulsions are used to prime-coat fabrics to improve the adhesion of subsequent coatings or to make them adhere better to plastic film. Plasticized emulsions are applied, generally by roller-coating, to the backs of finished rugs and carpets to bind the tufts in place and to impart stiffness and hand. For upholstery fabrics woven from colored yams, PVAc emulsions may be used to bind the tufts of pile fabrics or to prevent slippage of synthetic yams. 

Category 3 (test 10 minutes at 40 °C). Rubber articles which come into contact with food for not more than ten minutes, e.g., milk liners and milking machine tubes, roller coatings and conveyor belts (fatty foods only in both cases), gloves and aprons for food handling. 

Poor flow and leveling, particularly during roller coating, and the need for an external catalyst, are, however, problems with... 

Applying a coating of enamel on flat metal sheets prior to fabrication into a container, or a round container after it has been fabricated. Both are carried out by a roller coating process followed by a curing/drying operation. 

Application of paints by air spray, electrostatic spray, roller coat, dip, and other means can be readily performed and also can be done in existing equipment. 

Use of application methods that can use relatively high-viscosity paints is advantageous. Appropriate methods include roller coating, special electrostatic spray equipment, hot-spray techniques, and two-nozzle spray guns. 

The epoxy-polyamide system may also provide a base for paper and board coatings applied by rotogravure or roller-coating techniques. It is useful for coating plastics and particularly valuable as a resin system for zinc-rich paints. It may be formulated with exempt solvents specified under Rule 66 (37). Higher solid formulations, particularly those formulated with fatty amido amines, are available. These formulations reduce solvent pollution and allow for higher film builds (37, 38). 

---