Internal sizing composition for paper
AssigneeRaisio Chemicals Oy
InventorsClaes Zetter, Olof Malmstrom, Markku Nurminen
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Abstract
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.
Claims29
An internal sizing composition for increasing the hydrophobicity of paper, which comprises a water dispersion of a ketene dimer compound and degraded starch, wherein the weight ratio of the ketene dimer and the starch is at most 1:1, on the solid weight basis.
A sizing composition for hydrophobizing paper by internal sizing, which composition as hydrophobizing compounds contains ketene dimer and alkenyl succinic anhydride dispersed in water together with degraded starch, wherein the weight ratio of the hydrophobizing compounds and the starch is at least 1:1, on the solid weight basis.
A sizing composition for hydrophobizing paper by internal sizing, which composition as hydrophobizing compounds contains ketene dimer and rosin dispersed in water together with degraded starch, wherein the weight ratio of the hydrophobizing compounds and the starch is at least 1:1, on solid weight basis.
Dependencies are inferred from the claim text.