A comparative study of the effect of cellulose-based deep coating and pulp refining on the structural and mechanical properties of paper

Abstract

A new coating method was developed, based on cellulose regenerated from an N-methylmorpholine N-oxide (NMMO) solution applied to paper. In particular, the purpose of this study was to compare the effectiveness of the “deep coating” method using cellulose regenerated from NMMO solution and the classic pulp refining process as methods to improve paper mechanical properties and overall quality. The “deep coating” name comes from the fact that the coating process is combined with subsequent heating of the coating before its final solidification. As a result of this operation, deep penetration of the cellulosic solution into the paper structure occurs. This increases the contact surface of the solution with the cellulosic fibers, which increases the strength properties of the paper structure. It was found that the cellulosic coating increased the apparent density of the paper, the tensile strength, the elongation, the resistance to bursting, and the double fold number. However, the coating also decreased the air permeability and the tear resistance of the paper samples. Despite some technological difficulties, this method could be an attractive solution in the case of a need for additional functionalization of a paper structure.

Improving the Optical Properties and Filler Content of White Top Testliners by Using a Size Press

“…First, the dispersant used in the coating process helped in creating a more homogeneous suspension, which contributed to an even distribution of the GCC coating pigment. Second, the addition of 10% total solids of starch as a binder helped in binding the coating pigments together and improved the retention of the filler mineral . The presence of both GCC and starch in the coating suspension created a favorable environment for high levels of light reflectance, which improved the whiteness of the WTT paper.…”

“…Second, the addition of 10% total solids of starch as a binder helped in binding the coating pigments together and improved the retention of the filler mineral. 22 The presence of both GCC and starch in the coating suspension created a favorable environment for high levels of light reflectance, which improved the whiteness of the WTT paper. The whiteness of a paper is a color parameter that provides information about the color rendering capacity of the substrate and measures its reflectance across all wavelengths in the visible light spectrum (400–800 nm).…”

“…This method, similar to that used by wall plasterers, helps in reducing the roughness of the paper surface. The term “coated paper” refers to the process of applying the coating to the surface of the paper. − Traditional coating formulas commonly include an inorganic pigment such as kaolin, calcium carbonate (CaCO 3 ), or titanium dioxide (TiO 2 ); a binder like starch, polyvinyl alcohol, acrylic acid, carboxymethyl cellulose, or styrene butadiene latex; and other auxiliary components . The inorganic pigment serves as a colorant and filler, while the binder helps in holding the pigments together and adhering the coating to the paper surface.…”

“…19 − 21 Traditional coating formulas commonly include an inorganic pigment such as kaolin, calcium carbonate (CaCO 3 ), or titanium dioxide (TiO 2 ); a binder like starch, polyvinyl alcohol, acrylic acid, carboxymethyl cellulose, or styrene butadiene latex; and other auxiliary components. 22 The inorganic pigment serves as a colorant and filler, while the binder helps in holding the pigments together and adhering the coating to the paper surface. The auxiliary components are added to enhance specific properties, such as brightness or durability.…”

Effects of precipitated and ground calcium carbonate coating on mechanical properties of fluting paper

“…kaolin, calcium carbonate (CaCO 3 ) and titanium dioxide (TiO 2 )], a binder (e.g. starch, polyvinyl alcohol, acrylic acid, carboxymethyl cellulose, styrene butadiene latex) and additives are commonly included in traditional coating formulations (Krysztof et al , 2021). Although the mechanical characteristics of paper coatings have a substantial influence on the end-use performance of coated paper, the main focus has been on the printability of coated paper and the fluid dynamics of the coating mix (Morsy and El-Sherbiny, 2004).…”