Sizing and size retention mechanisms of alum-treated base paper by tub sizing with anionic rosin emulsion size were studied using some analytical methods and model experiments. Alum- or cationic polymer-treated base paper sheets were subjected to tub sizing with anionic rosin emulsion size, anionic and cationic petroleum resin emulsion sizes and anionic fatty acid emulsion size. Size retention ratios in the sheets were measured by pyrolysis-gas chromatography. Sizing levels as well as size retention ratios of paper by tub sizing with the anionic emulsion sizes increased with increasing aluminum content in the base paper sheets. The obtained results indicated that some cationic sites are formed at the aluminum components in the base paper sheets in water during the tub sizing process, and thus more anionic rosin size particles are adsorbed and retained in the alum-treated base sheets by electrostatic interactions. Furthermore, the formation of such electrostatic interactions brings about an anchoring or f ixing effect of the size particles in the sheets with more even size distributions. This anchoring effect by the aluminum components in the base paper sheets enhances sizing performance in tub sizing. The cationic polymer-treated base paper sheets had a sizing and size retention behavior similar to that of the alum-treated base paper, and thus the presence of some cationic sites in the base paper is required for tub sizing. Therefore, aluminum components in the base paper sheets participate in both size retention and distributions of size particles in the sheets in tub sizing, and greatly influence the resultant sizing behavior.
All Science Journal Classification (ASJC) codes
- General Materials Science