Abstract: The invention relates to a method of sizing paper and similar cellulose products containing precipitated calcium carbonate as a filler. According to the method, an aqueous suspension of pulp is dewatered and dried in the presence of an aqueous dispersion of a rosin-based sizing agent, which comprises a rosin component and a rosin ester component, and an aqueous dispersion of a cellulose-reactive sizing agent. The invention also relates to an aqueous dispersion of sizing agents which comprises a rosin-based sizing agent, which contains a rosin component and a rosin ester component, and a cellulose-reactive sizing agent.

Abstract: This invention relates to improved rosin sizes, and to improved methods for preparing sized paper. In one embodiment, sized paper is prepared by adding the improved rosin size and a polyamine retention aid to a pulp slurry before sheet formation, without the use of aluminum sulfate. In another embodiment, paper is surface-sized with the improved rosin size in the absence of both aluminum sulfate and retention aids.

Abstract: A sizing agent for use in paper-making comprises an aqueous emulsion of at least one compound of the formulae ##STR1## wherein each R.sup.1 represents a hydrophobic group selected from alkyl, alkenyl, aralkyl or aralkenyl groups, where the R.sup.1 groups in either formula may be the same or different and together they contain from 25 to 60 carbon atoms. The sizing agent can be used for either internal or surface sizing, and is effective in the absence of, or in the presence of, a retention aid.