*Viscosity:

From their working principle we could find that viscosity of chemical in air knife should be smaller because it is forced by air pressure. If viscosity too high the paper would be damaged by chemicals and high air pressure. So the viscosity we usually

suggested not over 500 CPS.

The viscosity of chemical in blade knife would have a wide range because the chemical is scrapped by the blade knife and higher viscosity is better for coating quality as well. So the viscosity range could be usually from 300-1500 CPS.

*Coating weight:

The coating weight also related to coating thickness.From the working principle, we could easily find that the thickness in an air knife should be lower than the thickness in a blade knife. Forced by air pressure, the chemical in the air knife coating would just tie to the paper rough surface; if there was too much coating weight, the chemical would be splashed and form pinholes, which seriously influenced the coating quality. So the coating weight of the air knife is usually suggested below 6 GSM.

From the blade knife working principle, enough coating weight could ensure chemical uniform filming. If the coating weight is not enough, the paper surface would have problems of uncovering of coating chemical.

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