Hak Lae Lee

The poor barrier properties and hygroscopic nature of cellulosic paper impede the wide application of cellulosic paper as a packaging material. Herein, a polyvinyl alcohol (PVA)-based polymer coating was used to improve the barrier performance of paper through its good ability to form a film. Alkyl ketene dimer (AKD) was used to enhance the water resistance. The effect of the absorptive characteristics of the base paper on the barrier properties was explored, and it was shown that surface-sized

Abstract Pre-flocculation is a technique that aggregates filler particles by means of polyelectrolytes. The size of the filler flocs is a critical factor affecting the properties of the paper. Process variables including the concentration of the flocculants, the stirring speed, and the dilution of the suspension change the size of the flocculated fillers. Ground calcium carbonate and cationic polyacrylamide were used to investigate the influence of these variables on flocculation. The median par

Abstract Due to the micro-sized pores on cellulosic substrate surface and the hygroscopic nature of cellulosic fibers, paper has poor barrier properties. Dispersion coating can improve the barrier properties of cellulosic paper noticeably by forming a continuous, non-porous polymer film on paper surface. In this work, the excellent film-forming performance of polyvinyl alcohol (PVA) was used to seal the surface pores of paper, thus enhancing the barrier properties. Alkyl ketene dimer (AKD) was a

The quality of coated paper, including its appearance and printing properties, is closely related to the structure of its coating layer, which is affected by components such as the pigment and binder. The binder, in particular, contributes to the structural formation and maintenance of the whole framework of the coating layer. Hydroxyethyl methacrylate (HEMA) is a hydrophilic monomer that is used as a functional monomer for the emulsion polymerization of styrene-acrylate (S/A) latex. In this stu

The glass transition temperature (Tg) of an S/B latex binder, which is highly related to the film-forming properties of latex, has long been of interest, and its effects on the properties of the coating layer are well-known. Measurements of the bulk and surface properties of coating layers or the properties of coated papers have been used to investigate the effect of Tg on the coating structure. However, these approaches cannot provide a detailed analysis of the coating structure because they gi

We have developed a new method for characterizing paper coating structure using FIB milling technique and FE-SEM. A new image analysis method combining smart blur and locally adaptive thresholding technique was applied. Compared to conventional method, this method preserved the edge of target and gave better automatic image segmentation of pores. We applied this method for the measurement of the pore structure in pigment coating layers. Staining with OsO4 and resin-embedding treatments were used

Abstract The adsorption characteristics of alkanes on high surface area cellulose were investigated by inverse gas chromatography. The enthalpy and entropy of adsorption of alkanes on the solvent exchanged cellulose were greater than the values on non-porous cellulose. The difference in the heats of adsorption of alkanes between the non-porous and the solvent exchanged cellulose was greater for larger molecules indicating stronger interaction for the higher alkanes in the pore structure. For n-h

The mechanical properties of paper coating layers are important in various processes and applications. Proper evaluation of the coating layers is essential for improving coating layer design. In this study, a novel method for the evaluation of the mechanical properties of coating layers was developed using a surface and interfacial characterizing analysis system (SAICAS) instrument, which has an important advantage of not requiring any special sample preparation process. Failure analysis results

Stickies contained in the recycled waste paper cause serious deterioration of product quality and paper machine runnability if they are not removed or controlled appropriately. To understand the stickies problem it is necessary to determine the amounts of macro and micro stickies in samples taken from various places in the papermaking processes. The effect of process modification or chemical additives on stickies control can then be evaluated. In this study, macro and micro stickies contained in

Abstract The partial solubility parameters of cellulose and AKD (Alkylketene dimer) treated paper were determined by inverse gas chromatography. The Snyder/Karger-Hansen interaction model was used, where -ΔEA = Viδl d + δl pδj p + δj h δj h). The adsorption internal energies of a series of n-alkanes and five polar probes were measured. From the ΔEA values of n-decane, acetone and THF, which give the largest normalized determinant M(n), the partial solubility parameters of the stationary phases w

Coated paper with a porous coating layer may have enhanced light-scattering ability and thus favorable optical properties. However, the increased porosity of such a coating layer is likely to decrease the strength of the coated paper, thereby adversely affecting the quality of the paper in the printing and converting processes. In this research, polymer-stabilized (PS) latex was prepared and used as a cobinder for the pigment coating of the paper. The PS latex particles were colloidally stabiliz