Roll coating techniques

There are different coating techniques. The woven and nonwoven fabrics normally involves three steps as it passes from the unwind roll to the rewind roll. Powder is metered onto the fabric, heated in an oven (gas or electric) that are usually divided into several heating zones, and cooled by a chill roll. 

A great variety of techniques is available but as a basis for vinyl wallcoverings two only have become popular—reverse-roll coating and screen coating—both of which have the virtues of accuracy and high speed. 

Proper solvent selection ensures that the vinyl-based polymers can be applied via conventional fluid techniques of spread and roll coating, dipping, spraying, brushing, etc. When used alone they behave as conventional lacquers. When used in conjunction with other polymer systems the reactive vinyl polymers permit crosslinking. 

Two-Roll Coating - Any coating technique in which two rolls are involved can be generally called two-roll coating. One roll is in contact with the liquid coating and transfers the liquid to a web that is wrapped around the second roll. The first roll is called the applicator roll and the second roll is called the back-up roll. 

Aside from the coating techniques presented here, flexo, screen, and offset printing can also be used to manufacture uniform films in roll-to-roll processes. These techniques are described in Section 4.4. 

Latex adhesives replace solvent-based adhesives more easily than solution adhesives. Most latex adhesives are produced from polymers that were not designed for use as adhesives. This is why they require extensive formulation in order to obtain the proper appUcation and performance properties. Application methods for latex adhesives include brush, spray, roll coat, curtain coat, flow, and knife coat. The bonding techniques used for latex adhesives are similar to those used for solvent adhesives. The following techniques are popular ... 

Wash-coating techniques for metal foils exist in automotive exhaust treatment technology [646]. Adomaitis et al. has presented the Metreon process, which was developed for coating of unstructured Fecralloy metal foils [646]. The foils wrapped up as coils were processed through rolls, where they received a corrugated structure. 

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