The present invention relates to a size composition of improving the water repellency of paper in papermaking by virtue of adding prior to web formation to the pulp slurry such a sizing dispersion that contains at least a ketene dimer compound as a hydrophobic sizing agent, and further contains colloidal starch in an amount which is at least 150% by weight of the hydrophobic sizing agent. The invention is particularly applicable for improving the water repellency of paper containing calcium carbonate as the filler.
CROSS-REFERENCE TO RELATED APPLICATION
This is a continuation in part of application Ser. No. 08/817,206 of Apr. 11, 1997, now abandoned, based on PCT/FI96/00051 of Jan. 25, 1996.
Solid mixtures of a reactive size and starch, which are obtainable by mixing at least one reactive size with at least one starch in a melt in the presence of at least one destructuring agent for starch under the action of shear forces at from 65 to 250.degree. C. and cooling the melt to room temperature, are used in the form of aqueous dispersions as process assistants in papermaking.
Additives for paper making are disclosed herein. Specifically, the additives are wax-free alternatives to conventional coatings, including ASA, AKD and optionally an acrylic containing composition. Other additives may be included in the coating, such as cationic particles or compositions. The coatings may be used at a variety of points during the paper making process, including on the calender stack and in the wet end.
The non-woven web of the present invention is comprised of recycled cellulose fiber and untreated Clarifier Sludge, and optionally, recycled glass fiber. Unlike uses of reclaimed Clarifier Sludge whereby the material has been treated in some fashion to improve its quality, the non-woven web of the present invention utilizes untreated Clarifier Sludge. The Clarifier Sludge of the present invention is dry enough to handle, and in one example varies between about 30% and about 45% solids. The Clarifier Sludge can be added to web-forming equipment (e.g., papermaking equipment) either in a waste paper disintegrator or into a recycling apparatus (e.g., broke pulper) whose output is metered into a refiner tank of the web-forming equipment. In an embodiment utilizing a broke pulper for introduction of the Clarifier Sludge, the broke pulper is filled with clarifier sludge and water to a consistency of about 3.5% solids.