Date of Award
Bachelor of Science
Paper Science and Engineering
Dr. Ellsworth H. Shriver
There are many variables which impact the final properties of coated paper. One of the major variables is the drying of the coating. Drying delay time is a significant factor which affects coated sheet properties. Delay times of 0, 5, and 10 seconds were used in this trial.
The cylindrical laboratory coater (CLC) was used to apply coating to paper stock, and the coated paper was tested to determine the effects of increasing the time interval between application of the coating colour to the point when the IR dryer was turned on.
It was found that increasing drying delay time affects both starch/latex and CMC/latex (carboxymethyl cellulose) coating colours. There is notable effect on roughness, porosity, pick, and optical properties.
Porosity, roughness, and K & N ink brightness reduction all experienced maximum values at 5 seconds of delay time. Opacity and brightness values were also greatest at 5 seconds delay time. Gloss measurements revealed lowest values at 5 seconds delay time due to high roughness of the sheet. The general trend of pick strength as measured by the wax pick test was a decrease in pick strength as delay time was increased. This was due to the loss of binder near the surface of the sheet as delay time was increased.
Bentley, Richard, "The Effect of Drying Delay Time on Paper Coatings" (1995). Paper Engineering Senior Theses. 16.