Polymer dispersion coated HD papers

High density papers use extensively beaten chemical pulp. The paper therefo re has a layered structure and closed surface with few large surface pores. Extrusion coating of these papers with polyethylene gives a structure with low oxygen and water vapor transmission rates. A similar improvement in ga s barrier is now possible by coating the papers with aqueous, nonchlorine b arrier polymer dispersions. Properties and grammage of the paper and coatin g are important. This technique offers an interesting alternative to conven tional extrusion coating.