Method of improving dewatering efficiency, increasing sheet wet web strength, increasing sheet wet strength and enhancing filler retention in papermaking
Methods of improving dewatering efficiency, increasing sheet wet web strength, increasing sheet wet strength, and enhancing filler retention in a papermaking process are disclosed. The methods improve the efficiency of drainage aids, wet web strength aids, and/or wet strength aids by coating at least some of the filler particles with a material that prevents the filler materials form adhering to a those additives.
1. A method of papermaking, comprising:
treating filler particles in a container with a composition of matter, in the absence of a cellulose fiber stock, by contacting the filler particles in the container with a rotating admixing apparatus having a distribution head rotating at a rotational speed of 1800 to 3000 rpm while the filler particles and the composition of matter are in the container, wherein the filler particles are selected from precipitated calcium carbonate, ground calcium carbonate, an organic pigment, an inorganic pigment, clay, talc, titanium dioxide, alumina trihydrate, barium sulfate, magnesium hydroxide, and any combination thereof;
combining the treated filler particles with the cellulose fiber stock thereby forming a filler and fiber stock combination, wherein the cellulose fiber stock comprises a plurality of cellulose fibers and water;
treating at least one of the cellulose fiber stock and the filler and fiber stock combination with a member selected from the group consisting of a wet strength aid, a wet web strength additive, a drainage additive, and any combination thereof; and
forming a paper mat;
wherein the distribution head is rotated by a drive, arranged in the container containing the filler particles, and associated with a rotational plane, the distribution head having, along a circumference thereof, which surrounds the rotational axis, distributed outlets from which the composition is passed into the container, the outlets comprising openings and the distribution head comprising mixing blades extending transverse to the rotational plane and having a length equal to at least half of an inner diameter of the container.
2. The method of claim 1 , wherein at least a portion of the precipitated calcium carbonate is in a form selected from the group consisting of undispersed calcium carbonate, dispersed slurry calcium carbonate, chalk, and any combination thereof.
3. The method of claim 1 , wherein at least a portion of the precipitated calcium carbonate comprises a dispersed slurry, the dispersed slurry comprising a member selected from the group consisting of a polyacrylic acid polymer dispersant, a sodium polyphosphate dispersant, a kaolin clay slurry, and any combination thereof.
4. The method of claim 1 , wherein the filler particles comprise 50% ground calcium carbonate and 50% precipitated calcium carbonate.
5. The method of claim 1 , wherein the composition of matter is a coagulant.
6. The method of claim 5 , wherein the coagulant is selected from the group consisting of an inorganic coagulant, an organic coagulant, a condensation polymerization coagulant, alum, sodium aluminate, a polyaluminum chloride, aluminum chlorohydroxide, aluminum hydroxide chloride, polyaluminum hydroxychloride, a sulfated polyaluminum chloride, polyaluminum silica sulfate, ferric sulfate, ferric chloride, epichlorohydrin-dimethylamine (EPI-DMA), an EPI-DMA ammonia crosslinked polymer, a polymer comprising ethylene dichloride, a dimethylamine polymer, a condensation polymer comprising diethylenetriamine, a condensation polymer comprising tetraethylenepentamine, a condensation polymer comprising hexamethylenediamine, a condensation polymer comprising ethylenedichloride, a melamine polymer, a formaldehyde resin polymer, a cationically charged vinyl addition polymer, and any combination thereof.
7. The method of claim 1 , wherein the composition of matter is a polymer comprising diallyldimethylammonium chloride (DADMAC) and acrylamide.
8. The method of claim 1 , wherein at least one of the drainage additive, the wet web strength additive, and the wet strength aid is selected from the group consisting of a glyoxylated acrylamide/DADMAC copolymer, a polyvinylamine, a polyvinylamide, a polydiallylamine, and any combination thereof.
9. The method of claim 1 , wherein the filler particles comprise ground calcium carbonate.
10. The method of claim 1 , wherein the filler particles exclude precipitated calcium carbonate.
11. The method of claim 1 , wherein the paper mat comprises a solid portion, the solid portion comprising greater than 50% by weight of the filler particles.
12. The method of claim 1 , wherein the composition of matter comprises a charge, the charge being the same as a charge of at least one of the drainage additive, the wet web strength additive, and the wet strength aid.