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US 4,445,970 AGranted
High mineral composite fine paper
AssigneePenntech Papers, Inc.
InventorsRichard L. Post, Robert G. Fort
Life of this patent
Estimating the term…
Abstract
Composite fine paper suitable for offset and gravure printing at high speeds and containing over 30% filler up to 70% filler for basis weights of 30-150 lbs/3300 ft.sup.2, is produced on a high speed paper-making machine from a furnish containing large quantities of filler, preferably a mixture of clay and talc, and including 3-7% of an ionic latex which is selected to provide good retention and good strength without leaving a residue on the screen.
Claims28
A method of manufacturing fine paper containing mineral filler at a high speed comprising:
- preparing an acidic paper furnish including paper-making fibers;
- an amount sufficient of mineral filler to retain internally in the fine paper web formed of 30-70% mineral filler, and wherein said mineral filler is system compatible;
- at least one retention aid agent which comprises a water soluble cationic polymer;
- and 3-7%, based on the dry furnish, of a cationic latex or amphoteric latex which is cationic at acid pH, said cationic or amphoteric latex being selected from latices which provide good mineral filler retention without substantial reduction in strength, which have a charge opposite to and less than the sum of the charges of the other ingredients of said furnish, and which precipitate on the fibers and fillers to exhaustion or near exhaustion;
- forming a wet paper web from said furnish such as to produce fine paper of thickness 1.5-15 mils and weight 30-150 lbs/3300 ft.sup.2 containing internally greater than 30% mineral filler up to 70% mineral filler, and having tensile and Z-directional strength sufficient to withstand high-speed offset or gravure printing;
- drying said web;
- and surface treating the dried web to improve the printability thereof.
4 more elements
Dependencies are inferred from the claim text.