Preparation and characterization of cellulose-based barrier coatings for producing a release-liner out of a porous base paper

Abstract

A novel silicone release liner was prepared from porous base paper with a simple biogenic polymeric pre-coat. The introduced method does not require the typical complex pretreatment processes for a paper sheet, such as calendering or pre-coating with clay. Biogenic polymers, hydroxyethyl cellulose and methylcellulose, were used to close the pores of the paper sheet. In addition, we used polyvinyl alcohol (PVA), a commonly used barrier coating with known film-forming capabilities, as a reference to close the pores and prevent silicone penetration into the base paper. In particular, hydroxyethyl cellulose showed promising barrier properties similar to those of PVA coatings. Methyl cellulose is less appropriate for release liner production due to poor film stability and insufficient adhesion to the underlying base paper. Barrier-coatings should be applied by a blade coater rather than a roller coater to obtain homogenous coatings. When a thin silicone layer was applied to the barrier-coated papers, the measured release forces were significantly reduced from 6.5 N/25 mm, for siliconized papers without any pre-coat, to less than 1 N/25 mm after pre-coating, particularly with hydroxyethyl cellulose.