Search

CN-122013588-A - Papermaking filler treatment method and paper product obtained by same

CN122013588ACN 122013588 ACN122013588 ACN 122013588ACN-122013588-A

Abstract

The present invention relates to a process for making paper comprising treating a filler with starch and a dry powder retention aid to form a filler composition of controlled particle size, mixing the filler composition with cellulosic fibers and forming paper, wherein the dry powder retention aid is used in an amount of 0.25 to 2.5 kg/ton relative to absolute dry filler and the starch is used in an amount of 2 to 64 kg/ton relative to absolute dry filler, such that the median particle size of the filler composition obtained after the filler has been treated with the starch and dry powder retention aid is in the range of 10 to 200 microns. The filler composition prepared by the method has controllable particle size and improved paper strength, and the starch and the dry powder retention aid used by the method are widely applied to the papermaking industry, and the on-site operation process of the method is simplified.

Inventors

  • RAO QINGLONG

Assignees

  • 饶庆隆

Dates

Publication Date
20260512
Application Date
20260316

Claims (11)

  1. 1. A method of making paper comprising: a, treating the filler with starch and a dry powder retention aid; b, combining the treated filler with cellulosic fiber raw material, and C, forming paper from the treated filler and cellulosic fiber raw materials; Wherein the dry powder retention aid is used in an amount of 0.25 to 2.5 kg/ton relative to the absolute filler and the starch is used in an amount of 2 to 64 kg/ton relative to the absolute filler; wherein the median particle size of the filler after treatment is from 15 microns to about 200 microns.
  2. 2. The method of claim 1, wherein the starch and the dry powder retention aid have been mixed together prior to treating the filler.
  3. 3. The method of claim 1, wherein the starch and the dry powder retention aid are added to the filler simultaneously.
  4. 4. The method of claim 1, wherein the filler is selected from one or more of calcium carbonate, sludge, kaolin, talc.
  5. 5. The method of claim 1, wherein the starch is selected from one or more of raw starch, nonionic starch, anionic starch, cationic starch, and zwitterionic starch.
  6. 6. The method of claim 5, wherein the starch is a cationic starch.
  7. 7. The method of claim 1, wherein the dry powder retention aid is selected from cationic polyacrylamide, polyvinylamine, polyethylenimine, or mixtures, block copolymers, grafts, or other derivatives thereof.
  8. 8. The method of claim 7, wherein the dry powder retention aid is a cationic polyacrylamide.
  9. 9. The method of claim 1, wherein the dry powder retention aid is present in an amount of 0.5 to 1.5 kg/ton relative to the oven dry filler and the starch is present in an amount of 4 to 32 kg/ton relative to the oven dry filler.
  10. 10. The method of any one of claims 1-9, the method further comprising: adding a charge regulator prior to adding the starch/dry powder retention aid composition; Wherein the charge regulator is one or more materials selected from the group consisting of alum, polyaluminium chloride, cationic polyacrylamide, polyethylenimine, polyamidoamine, polyepichlorohydrin amine, and anionic acrylamide and sodium acrylate copolymer.
  11. 11. A paper product prepared according to the method of any one of claims 1-10.

Description

Papermaking filler treatment method and paper product obtained by same Technical Field The present invention relates to, but is not limited to, the field of papermaking filler treatment methods and paper products obtained therefrom. Background The filler has long history of application in the paper industry. The addition of the filler increases the whiteness and opacity of the paper, improves the uniformity of the paper and promotes the improvement of printing performance. Because fillers are generally much less expensive than papermaking fibers, replacing fibers with fillers generally provides better economic benefits. As a result, the industry will use as much filler as possible in the papermaking process. However, the filler has small particle size and does not generate binding force with the fibers, and the use of the filler instead of the fibers causes a lot of negative problems such as reduction of retention, reduction of chemical efficiency, reduction of strength of paper and the like to the papermaking process and paper. Fillers are typically added to the thick or thin stock of a papermaking stock system, with retention of the filler on the paper being achieved by the addition of a retention aid. To increase the ash content of paper, it is common practice to increase the first layer retention of the slurry by increasing the amount of retention aid. However, increasing the amount of retention aid tends to result in larger pulp flocs, which in turn affects paper formation and in extreme cases results in reduced paper strength, affecting continuous operation of the machine and paper quality. One way to reduce these negative effects caused by the increased filler content is to pre-flocculate the filler before it is added to the wet-end processing system of the paper machine. The flocculation refers to adding one or more flocculation agents into the filler to form filler flocculation with controllable particle size distribution under a certain shearing force, wherein the size, distribution and stability of the filler flocculation are determined by the selection of the flocculation agents and the flocculation process. To prevent the false flocculation of a large amount of unfused filler re-entering the slurry system after shearing, which is caused by insufficient contact of some filler particles with the flocculant, medium and low molecular weight chemicals are typically used as the flocculant. The filler flocculation processed by the flocculation process can reduce the coverage of the filler on the fiber, thereby improving the fiber-fiber combination probability, improving the paper strength, reducing the adsorption of the filler on other wet-end chemicals and improving the efficiency of the wet-end chemicals. Furthermore, the flocculation process must be economically viable. CN107407054 authors disclose a paper making process for increasing the ash content of paper products by treating the filler with a flocculant having a molecular weight of 1,200,000 to 7,500,000 daltons to form filler aggregates having a particle size of 10 microns to 150 microns. The scheme is continuously and stably used on hundreds of paper machines at home and abroad, helps paper to improve ash content by 1-3%, and maintains paper quality and paper machine operation. However, there is a need for improvement in the solution, in which first the filler batt polymer formed by the solution does not form bonds with the fibers, resulting in limited paper strength improvement. Secondly, the scheme uses a medium-low molecular weight flocculating agent to ensure the full contact between the filler and the flocculating agent, and the dosage of medicines is required to be high in order to maintain a certain flocculating particle size of the filler flocculating agent in the paper machine head box. Furthermore, this solution requires the additional introduction of one or more flocculating agents to accomplish the flocculation technique, which creates challenges for layout, chemical quality control and production safety management of the wet end of the paper mill. WO03087472 discloses a filler treatment process comprising preparing an expanded starch-emulsion composition in the presence or absence of co-additives and adding said composition to a filler suspension. The use of treated fillers in the papermaking process increases filler retention and produces papers with higher filler content where filler addition has only minimal negative impact on strength properties. The expanded starch-emulsion composition may be prepared in a batch or jet cooker or mixed with hot water by a mixing device under controlled conditions (i.e., temperature, pH, mixing time) to expand the starch granules sufficiently to improve their performance as a filler additive while avoiding excessive expansion causing them to crack. The expanded starch-emulsion composition is then rapidly mixed with filler (preferably in a static mixer) and added before the papermaking stock