JP2015533954A - Filler suspension and its use in the manufacture of paper - Google Patents

Abstract

Provided herein is a filler suspension comprising ionic starch, complementary ionic co-additives and filler particles. Pulp furnishes containing the filler suspension and papers containing pulp furnishes are also provided. Also provided are processes for making filler suspensions and processes for their use in the manufacture of paper. Accordingly, one aspect of the present invention is a filler suspension for use in papermaking comprising filler particles, ionic starch and complementary ionic co-additives.

Description

  The invention herein relates to a filler suspension comprising filler particles, ionic starch and complementary ionic co-additives. Also provided are methods of using this suspension for the preparation of paper furnishes, and methods of making paper from the furnish.

  In the manufacture of filler paper, the filler slurry is conventionally added to the pulp suspension before being transferred to the forming section of the paper machine. A retention modifier or a retention modifier system comprising several components is generally added to the pulp / filler suspension to retain the filler in the resulting paper sheet and is used in the paper industry. Forms what is called a furnish.

  Adding fillers to the paper can provide many improvements in sheet properties including improved opacity, whiteness, texture, and print sharpness. Further, when the filler is less expensive than pulp, the addition of filler to the sheet results in cost savings. These savings can be substantial when low cost fillers such as precipitated calcium carbonate (PCC) are used to replace expensive chemical pulp fibers. In addition, filled paper can be easier to dry than paper without filler, and as a result, the paper machine can run faster with less steam consumption, which further reduces costs. And can improve productivity.

  However, there is a limit to the amount of filler that can be added for a given sheet weight. Other factors such as retention, drainage and sizing should also be considered, but the resulting paper strength is the most important factor along with the paper machine efficiency that limits the filler content.

  Producing paper with a high filler content requires an efficient retention modifier system. The retention improver should provide good filler retention under the high shear and turbulence that occurs in the paper manufacturing process and should improve drainage without impeding formation. Retention improving chemicals are generally added to the furnish before or at the entrance to the paper machine headbox. Retention modifiers typically improve filler and fines retention by crosslinking and / or agglomeration mechanisms and are one, two or three component chemical additives. These chemicals can cause filler particles and fines (small fibrous fragments) to adhere to long fibers, or they can agglomerate into larger agglomerated particles that are more easily retained in the web. Help to cause. In order to produce this adhesion and agglomeration, these chemicals must adsorb on the surfaces of fillers, fines and fibers. The degree of adsorption and adhesion of chemicals depends on the cleanness of the furnish and the chemical properties of the furnish, the properties of the added chemical, the degree of shear in the papermaking process and the retention modifier and furnish ingredients. It is affected by many things including the contact time between.

  An ongoing industry trend is to increase the filler content in paper to further reduce costs. However, the strength of the paper is not only because there are fewer fibers in the sheet, thereby reducing the number of fiber-fiber bonds, but also because the presence of the filler reduces the contact between the remaining fibers, Reduced by replacement of fiber with filler. The filler particles do not bond between themselves and their positioning in the fiber-fiber bonded region prevents hydrogen bonding from occurring between the pulp fibers. As a result, large quantities of fillers produce more fragile sheets that can be more easily torn in paper machines, sizing presses, coating machines, winders and printing presses. More fragile fiber-fiber bonds also reduce the surface strength of the paper, causing reduced pick resistance and increased linting. Insufficient bonding of filler particles in the fibrous structure can also increase dust in the press chamber.

  In general, all inorganic fillers commonly used in papermaking (eg, but not limited to clay, heavy calcium carbonate (GCC), precipitated calcium carbonate (PCC), chalk, talc, titanium dioxide, heavy Calcium sulfate (GCS) and precipitated calcium sulfate (PCS)) are known to reduce paper strength and increase chemical requirements. Fillers with large surface areas have a substantial negative impact on strength and increase the chemical need for additives used for strength, sizing and retention. Due to its shape and narrow particle size distribution, PCC has a tendency to reduce bonding in the sheet and also makes the sheet more permeable than other common papermaking fillers such as chalk, GCC and clay Or give the sheet an open structure that makes it porous. As filler content is increased in the furnish, the need for sizing chemicals such as alkyl ketene dimers (AKD) and alkenyl succinic anhydrides (ASA) maintains the desired degree of sizing / waterproofing. To be increased. This is because an unbalanced portion of the sizing chemical is adsorbed on the filler particles. In recent years, many paper mills producing wood-containing paper grades have switched to neutral paper making it possible to use bright calcium carbonates such as GCC and PCC. However, major interest regarding the use of calcium carbonate fillers in these grades of paper remains, particularly in the areas of retention, sheet strength and printing operations.

  Another ongoing industry trend is to reduce the weighing of the sheets to reduce costs. Unfortunately, as the weight is reduced, almost all paper properties, including the limiting factors of opacity, bending stiffness and permeability, deteriorate. Reduction in weighing can also reduce filler retention during the papermaking process and can increase the frequency of sheet tearing both on the paper machine and during print processing and printing. To overcome the loss in sheet opacity, papermakers can add more high opacity fillers, but this can cause further deterioration in sheet strength. The industry requires cost-effective techniques for the production of lightweight grades of paper with good filler retention and drainage and acceptable strength, formation, optical and printing properties.

  Accordingly, one aspect of the present invention is a filler suspension for use in papermaking comprising filler particles, ionic starch and complementary ionic co-additives.

  In one aspect of the present invention, the filler particles comprise clay, talc, synthetic silicate, magnesium magnesium aluminosilicate, sodium aluminosilicate, heavy calcium carbonate (GCC), chalk, precipitated calcium carbonate (PCC), heavy sulfuric acid. Selected from the group consisting of calcium (GCS), precipitated calcium sulfate (PCS), titanium dioxide and combinations thereof.

  In one aspect of the invention, the ionic starch is a raw starch.

  In one aspect of the invention, the ionic starch is a swollen ionic starch.

  In one aspect of the invention, the ionic starch is a cooked ionic starch.

  In one aspect of the invention, the ionic starch is cationic.

  In one aspect of the invention, the ionic starch is anionic.

  In one aspect of the invention, the ionic starch is amphoteric.

  In one aspect of the invention, the ionic starch comprises corn starch, rice starch, potato starch, cassava starch, tapioca starch, waxy corn starch, wheat starch, sorghum starch and waxy sorghum starch. Selected from the group consisting of

  In one aspect of the invention, the swollen ionic starch is formed by heating an aqueous suspension of the raw starch at a gel point temperature of the raw starch of ± 10 ° C.

  In one aspect of the present invention, the swollen ionic starch is formed by heating an aqueous suspension of the raw starch in a temperature range from the starch gel point temperature to the starch gel point temperature + 10 ° C. The

  In one aspect of the invention, the complementary ionic co-additive is an anionic flocculant.

  In one aspect of the invention, the anionic flocculant comprises a copolymer of acrylamide and sodium acrylate.

  In one aspect of the present invention, the complementary ionic co-additive is selected from the group consisting of NALCO61815, Nalco61816, Nalco61830, Fennosil® ES210, Fennosil® ES211, Telioform® M305. The

  In one aspect of the invention, the complementary ionic co-additive is an anionic inorganic microparticle.

  In one aspect of the invention, the anionic inorganic particles are selected from the group consisting of bentonite, colloidal silica, sodium borosilicate, aluminum hydroxide, or combinations thereof.

  In one aspect of the invention, the complementary ionic co-additive is nanocellulose.

  In one aspect of the invention, the complementary ionic co-additive is polyvinyl alcohol.

  In one aspect of the invention, the complementary ionic co-additive is an anionic or amphoteric PVAm.

  In one aspect of the invention, the complementary co-additive is a biopolymer.

  In one aspect of the invention, the biopolymer is starch based.

  In one aspect of the invention, the starch-based biopolymer is EcoSphere® 2202 binder.

  In one aspect of the invention, the complementary ionic co-additive is anionic polyacrylic acid or a sodium salt of polyacrylic acid.

  In one aspect of the invention, the complementary ionic co-additive is a natural polymer.

  In one aspect of the invention, the natural polymer is selected from the group consisting of carboxymethylcellulose, natural rubber, soy polymer, or combinations thereof.

  In one aspect of the invention, the filler particles are precipitated calcium carbonate.

  One aspect of the present invention is a pulp furnish comprising pulp fibers and a filler suspension of the present invention.

  In one aspect of the present invention, the pulp furnish includes a sizing agent, a dry strength agent, a wet strength agent, a retention improver, and other functional chemicals (eg, optical brighteners, dyes, And an additive selected from the group consisting of an agent, bioside and combinations thereof.

  One aspect of the present invention is a paper product comprising the above pulp furnish.

(Detailed explanation)
FIG. 1 is a schematic diagram of a papermaking process in which ionic water starch, complementary ionic co-additives and filler particles are added to an aqueous medium essentially simultaneously.

FIG. 2 is a schematic diagram of a papermaking process where complementary ionic co-additives are premixed with ionic starch in an aqueous medium prior to the addition of filler particles.

FIG. 3 is a schematic diagram of a papermaking process in which complementary ionic co-additives are premixed with filler particles in an aqueous medium prior to addition of ionic starch starch.

FIG. 4 is a schematic diagram of a papermaking process where ionic starch is premixed with filler particles in an aqueous medium prior to the addition of complementary ionic co-additives.

FIG. 5 is a graph of the viscosity response of potato starch when heated to and beyond the gel temperature.

FIG. 6 includes microscopic images of potato starch granules when heated in water at various temperatures.

FIG. 7 is a graph showing the tensile strength of paper sheets made using various filler compositions including the filler composition of the present invention.

FIG. 8 is a graph showing the stiffness of paper sheets made using various filler compositions including the filler composition of the present invention.

(Short description of the table)
Table 1 shows a paper in paper made using a filler composition comprising swollen cationic starch and a filler composition comprising swollen cationic starch + anionic micropolymer co-additive. A comparison of sheet properties is shown.

  Table 2 shows a comparison of paper sheet properties for paper made using a filler composition with the composition components added in different order of addition.

  Table 3 shows paper made with PCC filler treated with swollen cationic starch only, and paper made with PCC filler treated with swollen cationic starch and co-additives. The comparison of improvement in tensile strength is shown.

  Table 4 shows a comparison of percent improvement in specific paper tensile strength / break length depending on the order of addition of swollen starch and various co-additives to the PCC.

    Table 5 shows a comparison of tensile strength improvement over non-PCC treated baseline in paper as a result of various PCC treatments.

    Table 6 includes PCC treated with swollen cationic starch or PCC treated with cooked cationic starch, or PCC treated with cooked cationic starch with various co-additives Figure 3 shows a comparison of paper properties using a filler composition.

(Discussion)
Unless expressly stated otherwise, the use of the singular herein includes the plural and vice versa. That is, "a" and "the" refer to one or more whatever the word modifies. For example, “a lightly cross-linked polymer” includes one such polymer, two such polymers, or even a larger number of such polymers under the right circumstances. Similarly, such as, but not limited to, “sizing agents” (unless it is clearly stated or otherwise clear from the context) that such is not intended. The term may refer to a plurality of such agents or simply a single such agent.

  Approximate terms (eg, including but not limited to “about”, “substantially”, “essentially” and “approximately”) are such that the features so modified It does not have to be the described feature, which means that it can vary to some extent from the described feature. The extent to which the description can vary is how much change can be enacted, and how much change will allow one of ordinary skill in the art that the modified feature still has the required characteristics and possibilities of the unmodified feature. It depends on whether or not it is recognized that it has. In general, however, in accordance with the above discussion, explicitly stated or implied values modified herein by approximate language may vary ± 15% from the stated values.

(Composition)
In one embodiment herein, a filler for use in papermaking comprising filler particles, ionic starch and complementary ionic co-additives in a liquid vehicle (typically water). A suspension is provided.

  In another embodiment, a pulp furnish is provided comprising a filler suspension and pulp fibers as described herein in an aqueous vehicle. The furnish may also contain other papermaking agents.

  In yet another embodiment, a method is provided for producing paper by adding a filler suspension of the present invention to a pulp fiber stock to form a pulp furnish and then manufacturing the paper from the furnish. Is done. Other anionic and cationic agents can be added to the furnish to improve retention and improve drainage. As previously mentioned, the furnish may also include other papermaking agents as are known to those skilled in the art.

  The present invention also provides a process for producing starch / co-additive compositions and combinations thereof with filler particles to form a filler suspension.

  The starches herein may be raw, swollen, cooked, or a combination thereof.

  As used herein, “raw” starch is sufficient to be in a swollen or cooked state (these states are as described below). Refers to starch that has not been exposed to treatment with hot water or steam.

  As used herein, a “swollen” starch is preferably water so that no further water can be absorbed without breaking the swollen granules at this time. Refers to raw starch that has absorbed and expanded. Exemplary swollen starches suitable for use in the filler suspensions herein are each incorporated by reference as if fully set forth herein. Including but not limited to those disclosed in patents 7,074,845; 7,625,962; and 8,354,004.

  In general, the preparation of swollen starch requires that swelling be performed under carefully controlled temperature and time conditions. Other parameters of interest include slurry pH, consistency and mixing. The control parameters vary from starch type to starch type and are usually determined empirically for each type of starch before being used in factory scale paper production. The general procedure is to suspend the raw ionic starch in cold water and then heat the suspension until the starch is swollen. This swollen starch may then be added in any desired order (i.e., all ingredients may be added essentially simultaneously, or any two ingredients may be premixed and the remaining ingredients subsequently added. May be mixed with complementary ionic co-additives and filler particles to form a filler suspension. For example, in FIG. 1, swollen ionic starch 1, complementary ionic co-additive 8a and filler particles 2 are mixed in a mixer 4 to form a filler suspension, which is then mixed with the mixer. 5 where it is mixed with pulp fiber 3 to form a furnish. In FIG. 2, the swollen ionic starch 1 and the complementary ionic co-additive 8a are premixed and then the combination is mixed with the filler particles 2 in the mixer 4 and then the formed packing. The material suspension is mixed with the pulp fiber 3 in the mixer 5. In FIG. 3, complementary ionic co-additive 8a is premixed with filler particles 2 and the combination is mixed with ionic starch 1 in mixer 4 and this formed filler suspension. Is moved to a mixer 5 where it is mixed with pulp fibers 3 to form a furnish. In FIG. 4, ionic starch 1 and filler particles 2 are premixed in mixer 4 and this premix is moved to mixer 5, where complementary ionic co-additive 8 a is essentially mixed with mixer 4. It is added to this premix during the passage between the mixers 5. In each of these aspects, the furnish containing the filler suspension is then moved to the paper machine 6 with additives 7 as needed to form paper 9. During the operation of drying the paper, the retained swollen starch granules break and liberate amylopectin and amylose macromolecules, which act to bind the solid components of the sheet.

  As used herein, “cooked” starch is heated to a temperature above the gel point, and the starch granules swell and essentially all the swollen granules break. Says starch maintained at that temperature until.

  The combination of ionic starch, ionic co-additive and filler particles can be used for papermaking under acid, neutral or alkaline conditions. This composition is primarily used to ensure that the filler and starch are well retained in the paper sheet during the papermaking process while having a minimal adverse effect on sheet strength. Using an ionic starch / ionic co-additive / filler particle composition tends to provide greater strength than using a single starch or co-additive with the filler particles.

(Filler)
The filler particles can be any known to those skilled in the art, and the filler suspension can contain a single type of filler or more than one type of filler. Filler particles typically have an average particle size ranging from 0.5 to 30 μm, more commonly from 1 to 10 μm, typically inorganic materials such as clay, heavy calcium carbonate (GCC), chalk. , Precipitated calcium carbonate (PCC), talc, heavy calcium sulfate (GCS) and precipitated calcium sulfate (PCS), titanium dioxide, synthetic silicates, sodium magnesium aluminosilicate, sodium aluminosilicate and blends thereof. It is not limited.) The pulp slurry to which the filler suspension is added can be composed of mechanical pulp, chemical pulp, regenerated pulp and mixtures thereof.

(starch)
Starches suitable for use in the present invention include, but are not limited to, starches derived from corn, waxy corn, potato, wheat, tapioca, sorghum, waxy sorghum and rice. Starch can be cationic, anionic or amphoteric; any of these forms are well known in the art and are generally commercially available. According to a non-limiting example method, the starch may be made cationic by the inclusion of quaternary ammonium cations in the starch, or made anionic by including carboxyl groups or sulfate groups in the starch. Alternatively, and may be made amphoteric by preparing a starch comprising a combination of the above. Since all these ionic starch forms are well known to papermakers, they are not further described herein.

Starch granules are insoluble in cold water. The starch is heated in an aqueous suspension to disperse or “cook” the starch. As the heating proceeds, the starch granule undergoes a critical temperature (strong swelling, referred to as “pasting”, “gelatinization” or simply “gel” temperature, A minor reversible swelling phase is first passed until a temperature is reached that causes a significant increase in viscosity. If maintained for a sufficient period above the gel temperature, the viscosity returns to a lower level due to the breakage of the swollen granules. Every type of starch has its own gelation temperature. Many starch gelling temperatures are available in existing literature,
Or it can easily be determined empirically by heating a given starch suspension while monitoring the viscosity. Swelled starch granules are different from cooked starch. Cooked starch results when the swollen starch granules break apart at temperatures above the gelling temperature and thereby release amylose and amylopectin that dissolve in the aqueous medium.

  By carefully controlling the processing of a particular starch, the starch can be swollen or cooked. For swollen starch, depending on the source of the starch, the final particle size of the swollen starch granules ranges from about 25 μm to about 100 μm. An example of the preparation of a typical but non-limiting swollen starch is given in the examples.

(Co-additive)
Co-additives are included in the filler suspension to improve the effect of the ionic starch in improving the properties of the paper by modifying the filler suspension. The co-additive may be cationic, anionic, or amphoteric. This is selected to have a net charge that is complementary to the net charge of the ionic starch. By “complementary”, if the starch was cationic, now
It is meant that the co-additive is preferred to be anionic and vice versa. If the starch is amphoteric, the co-additive may be cationic, anionic, or itself amphoteric. Anionic co-additives include, but are not limited to, carboxymethylcellulose, nanocellulose, polyacrylic acid, alginate, colloidal silica, bentonite, polyacrylamide, natural rubber and soluble soap. Cationic co-additives include, but are not limited to, polyethyleneimine, chitosan, polyvinylamine, poly (dadmac), polyacrylamide, alum, trivalent and tetravalent cations. Soy polymer may also be used as a co-additive. More than one co-additive may be used with certain starches and fillers.

  A non-limiting example of an amphoteric co-additive suitable as a co-additive for use in the filler suspensions of the present invention is Ashland-Hercules Hercobond® 1303.

  Other materials suitable for use as co-additives in the filler suspensions of the present invention include anionic colloidal silica nanoparticles (eg, Eka NP® 090, Eka NP® 200, Eka NP (registered trademark) 320, Eka NP (registered trademark) 32K, Eka NP (registered trademark) 442, Eka NP (registered trademark) 590/670, Eka NP (registered trademark) 780, Eka NP (registered trademark) 882, Eka NP (R) 890 and Eka NP (R) 2180, all from AlzoNobel; Fennosil (R) 525 from Kemira, and POSITEK (R) 8699 from Nalco, including but not limited to .)

  Also suitable for use as co-additives in the filler suspensions of the present invention are Nalco Ultra POSITEK® 8692, 8893, BD420 and TR420, which are sodium borosilicate nanoparticles (typically 1 to 100 nm in size).

  Altonite® from S & B Industrial Minerals, Fenollite® LF5 from Kemira and Hydrocol® from BASF are suitable for use as co-additives in the filler suspensions of the present invention Bentonite.

  Anionic aluminum hydroxide microparticles are also considered suitable for use as a co-additive in the filler suspensions of the present invention.

  Perform SP® 7200 and 9232, an anionic acrylamide copolymer from Hercules Incorporated (now Ashland-Hercules), are also suitable for use as co-additives in the filler suspensions of the present invention. . Perform (R) 7200 is disclosed in MSDS 999 1060 1076, Ver. 3.

  A copolymer of sodium acrylate and acrylamide dispersed in mineral oil, as described in the MSDS issued March 23, 2006 from Ciba Specialty Chemicals Corporation (now BASF) Trademark M305 is likewise suitable as a co-additive for use in the filler suspensions of the present invention. Other Telioform® compositions (eg, including but not limited to Telioform® M100, M135, M200, M300, S10, M100A, M8A and SC22) are also fillers of the present invention. It may be suitable for use as a co-additive in suspension.

  An anionic form exemplified by Fennosil® ES-210, Fennosil® ES-211 (both based on acrylamide / acrylic acid copolymer) and Fennosil® ES-325; and Fennosil (Registered trademark) E130 (formulation containing acrylamide / p-amine), E128 (formulation containing polyacrylamide / polydimethyldiallylammonium chloride (DADMAC) copolymer), ES-325 (formulation containing polyacrylamide / salt) Also suitable as co-additives in the filler suspensions of the present invention are additives of the Fennosil® family comprising cation forms exemplified by E-126 and acrylamide / p-amine.

  Nanocellulose as described in (but not limited to) WO 2007/091942 and WO 2009/126106, both of which are hereby incorporated by reference in their entirety, is also described in this book. Suitable as a co-additive for use in the inventive filler suspension.

  Yet another material that is currently considered suitable for use as a co-additive in the filler suspensions of the present invention is a cellulose-based material such as Engineered Cellulose Additive (ECA) from AkzoNove. And noble fibrils as described in US Pat. No. 6,156,118, which is incorporated by reference as if fully set forth herein; hemicellulose and highly hemicellulose-containing materials.

  Carboxymethylcellulose (CMC) is also suitable as a co-additive in the filler suspension of the present invention.

  Natural rubbers such as guar and xanthan are also suitable co-additives in the filler suspensions of the present invention.

  Other materials currently considered to be suitable co-additives for use in the filler suspensions of the present invention are the glyoxylated DADMAC / acrylamide copolymer compositions NALCO 64110, 64114 and 64170 and An anion that is a copolymer of acrylamide and sodium acrylate, as generally described in US Pat. No. 8,088,213, incorporated by reference as if fully set forth herein. NALCO 61815, 61816 and 61830, which are sexual flocculants.

  Yet another material suitable for use as a co-additive in the filler suspensions of the present invention is Ashland-Hercules Hercobond® HA5305 and SP7200 and Eka PL8660.

  Polyvinyl alcohol (PVA) is likewise suitable for use as a co-additive in the filler suspension of the present invention.

  Also suitable as co-additives in the filler suspensions of the present invention include anionic polyvinylamine (PVAm) and amphoteric polyvinylamine (eg, amphoteric terpolymers of vinylformamide, vinylamine and acrylic acid, A non-limiting example of this is XELOREX® F3000 from BASF, but is not limited to this.

  Biopolymers can also be used as co-additives in the filler suspensions of the present invention. Suitable biopolymers for use as filler additives include, but are not limited to, starch-based biopolymers. The biopolymer can be micro- or nanoparticulate. Biopolymers include, but are not limited to, EcoSphere® 2202 binder from Ecosynthetics of Burlington, Ontario, Canada.

  If the co-additive is a polymer, it may be uncrosslinked, lightly crosslinked, or heavily crosslinked

  The co-additive may be water-soluble or water-insoluble. A non-limiting example of a water-soluble co-additive is the polyacrylamide-based anionic polymer Telioform® M303.

  The polymeric co-additive can be a micropolymer. As used herein, “micropolymer” refers to polymeric particles obtained by emulsion polymerization, dispersion polymerization, and water-in-water polymerization, in which the reaction of a water-soluble monomer is a coagulant ( For example, but not limited to, polyamines such as DADMAC or DIMAPA). Micropolymers may be “structured”, that is, they may have a three-dimensional structure in which the individual polymer strands in the polymeric particles are stable.

  By “lightly cross-linked” it is meant that the crosslinked polymer remains substantially water soluble. That is, lightly cross-linked polymers appear to resemble “branched” polymers rather than fully cross-linked polymers in which the polymer chains are intertwined intimately and thus rendered insoluble in water. As used herein, lightly crosslinked and branched are used interchangeably to refer to a polymer that is crosslinked but still water soluble. Examples of anionic, branched, water soluble polymers are described in US Pat. No. 5,958,188, 6, incorporated herein by reference in its entirety as if fully set forth herein. 391,156 B1, 6,395,134 B1, 6,406,593 B1 and 6,454,902 B1.

  “Heavy crosslinking” simply refers to a polymer that is soluble when uncrosslinked or lightly crosslinked, but is no longer water soluble as a result of the degree of crosslinking.

(Filler / ionic starch / ionic co-additive suspension)
Generally, this suspension contains 60 to 99.5% by weight filler, 35 to 0.499% by weight ionic starch and 5.0 to 0.001% by weight complementary ionic co-additives. , Based on the total solids content of filler particles, ionic starch and complementary ionic co-additives.

  The suspension contains a complex of ionic starch and complementary ionic co-additive, but it is understood that free ionic starch and free ionic co-additive may also be included.

(Paper making agent)
The compositions, suspensions and furnishes herein further include conventional papermaking agents (eg, sizing agents such as alkyl ketene dimers, alkenyl succinic anhydrides and rosins; wet and dry strength agents and cationic Or anionic polymeric retention modifier, but is not limited thereto). This composition consists of a single chemical (eg anionic microparticles (colloidal silicic acid, bentonite), anionic polyacrylamide, cationic polymer (cationic polyacrylamide, cationic starch)), two-component chemical system (Cationic polymer / anionic microparticle, cationic polymer / anionic polymer) or three-component system (cationic polymer / anionic microparticle / anionic polymer, cationic polymer / anionic micropolymer / anionic polymer) Possible retention modifiers may be included. The selection of retention modifier chemicals and their point of addition in the paper forming process depends on the nature of the ionic charge of the treated filler slurry, the papermaking furnish and the shear forces generated in the papermaking process.

  Generally, the filler suspensions herein are used in amounts of 5% to 70% as dry solids based on the dry weight of the pulp in the furnish.

  A paper sheet made with a filler suspension according to the present invention may show better internal bond strength than a control sheet made without filler treatment, as measured by the Scott bond technique. . With the same filler content, the wet and dry strength properties of sheets made using the filler suspensions herein can be greater than sheets made with filler alone.

  The use of the filler suspension of the present invention enables the production of filled papers such as fine coated and uncoated paper, supercalender paper and newsprint paper with minimal strength loss and good optical properties. . Thus, using the filler suspension of the present invention may allow a papermaker to produce a filled paper having a higher filler content in the paper sheet. In general, the potential benefits from using the treated filler suspensions of the present invention are improved sizing, wet strength, dry strength and printability, and / or reduced use of expensive reinforced chemical pulp fibers. including.

  Under certain conditions, the combination of ionic starch and ionic co-additive can be used to enhance paper grades that do not include fillers such as bag paper and paperboard products.

  The examples provided below are intended to be merely an aid to understanding various aspects of the present invention. They are not intended nor should they be construed as limiting the scope of the invention in any manner.

(General)
In the examples below, the results were obtained using laboratory scale techniques.

  When the starch to be used is raw, it can be suspended in water, or it can be suspended in water and not swell the starch to a significant extent or digest this It may be heated to a temperature that is well below its gel point.

  On the other hand, if swollen starch is desired, the raw starch in an aqueous slurry that is typically 0.5 to 20% solids at room temperature can be mixed in a batch digester, jet digester, or hot water. Can be swollen at a temperature close to the gel point of the starch. A preferred method is to swell the granules by mixing a starch slurry prepared in cold water with hot water. The temperature of the hot water used depends on the consistency of the initial starch slurry in cold water, the final target temperature of the swollen starch, the temperature of the cold starch slurry, the pH and the residence time. The temperature and reaction time for preparing the swollen starch depends on the type of starch used, the pH of the starch slurry and the heating time. The following is an example of a process for the preparation of swollen starch for the purposes of the present invention.

Example 1
The raw ionic starch dispersion in cold water is swollen by heating it to a temperature close to the gel point of this particular starch. When the starch is swollen, complementary co-additives are added and the mixture is added to the stirred filler suspension.

(Example 2)
The starch dispersion is first swollen and then added to the stirred filler suspension, followed by the co-additive. In this method, the starch powder is dispersed in cold water and then mixed with hot water or heated to a temperature close to the starch gel point. The swollen starch is then rapidly mixed with the filler suspension at a temperature below the starch gel point, followed by the co-additive.

(Example 3)
The starch suspension is first swollen and then added to the stirred co-additive / filler suspension. In this method, the starch powder is dispersed in cold water and then mixed with hot water or heated to a temperature close to the gelation temperature of this particular starch. The swollen starch is then rapidly mixed with the filler suspension.

  The combination of swollen starch, co-additives and fillers is performed under good mixing conditions. Other additives can be added during the preparation of the starch / co-additive / filler suspension to form a composite with the filler prior to the addition of swollen starch and co-additives. .

  The treated filler suspension can be introduced directly into the pulp slurry, or can be diluted if desired, and at the entrance of a sheet forming process (eg, mixing chest, machine chest, or fan pump). ) Before the pulp stock of the paper machine. In general, treated filler suspensions tend to maintain agglomeration characteristics over time when added to a papermaking pulp slurry. Anionic microparticles (colloidal silica, bentonite, organic micropolymers), anionic polymers (anionic polyacrylamide), cationic polymers (cationic polyacrylamide), cationic polymers ( The dosage of retention improvers such as cationic polyacrylamides (cationic starches) can be increased.

Example 4
A 0.3% strength stock was prepared by mixing the internal cationic starch with a pulp furnish, followed by pre-treated PCC, and finally a retention modifier. An 80 g / m ² wood-free handsheet was made using a dynamic sheet former (DSF) followed by dynamic sheet pressing and dried at 120 ° C. Prior to the paper test, the paper sheet was colandered under the same conditions and then placed under conditions of 50% relative humidity (RH) and 22 ° C.

The raw materials used in the sheet making were:
Fiber: 100% eucalyptus was used as the pulp and was beaten to a SR value of 30 (at 20 ° C.) using a Valley Beater lab beater.

  Filler: Specialty Minerals Inc. Precipitated calcium carbonate (ALBACAAR® LO PCC), average particle size 2.3 μm. The PCC content in the sheet varied between 19.3% and 25.9% by weight.

  Swelled cationic starch used for PCC pretreatment: Cationic potato starch. The swollen cationic starch was prepared by mixing dry cationic starch powder with water to make a 3% solids slurry and then heated to 63 ° C. with mixing. The swollen cationic starch was used for PCC pretreatment by mixing 5 kg swollen cationic starch per metric ton (metric ton, tn) of paper with PCC at 20% solids. Some filler samples were only pretreated with swollen cationic starch, and some were pretreated with swollen starch and anionic co-additives.

  Co-additives used for PCC pretreatment with swollen cationic starch: anionic micropolymer (TELIOFORM M305®, registered trademark of BASF). PCC treatment was performed by mixing swollen cationic starch and anionic micropolymer with PCC. Different addition sequences were used and the amount of swollen cationic starch was fixed on 5 kg / metric ton paper while the amount of anionic micropolymer was 0.05% as received material / dry PCC weight. Yes, and 0.1% as received material / dry PCC weight.

Internal starch: Cationic potato starch. The dried starch powder was mixed with water until a 1% solids slurry was cooked at 97 ° C. with subsequent mixing. The cooked cationic starch was used at 8 kg / paper metric ton by mixing it with pulp furnish.
Retention modifier: 0.2 kg / metric ton of cationic polyacrylamide (CPAM) was used for retention.

(Example 5)
Table 1 shows the properties of sheets made from PCC treated with swollen starch only, and PCC treated with swollen starch followed by anionic micropolymer. The amount of anionic micropolymer was 0.05% to 0.1% as received material / dry PCC weight. Compared to PCC treated with only swollen starch, the sheet with anionic micropolymer in PCC pretreatment exhibits better strength properties-tensile, internal bond, bending stiffness. The best strength performance was achieved with 0.1% anionic micropolymer content. This allows for an increase in filler by 6% without loss in strength properties.

  PCC: precipitated calcium carbonate, SST: cationic swollen starch, AMP: anionic micropolymer.

  Tensile and stiffness values are geometric means from the machine direction and the cross direction.

(Example 6)
Table 2 presents the properties of PCCs treated with swollen starch only, and sheets made with PCC treated with starch and anionic micropolymers swelled using different order of addition: swollen PCC treated with an anionic micropolymer following the modified starch, and a PCC treated with the starch that was subsequently swollen after being treated with the anionic micropolymer. The presence of anionic micropolymers improves the strength properties of sheets made of PCC treated with swelled starch independent of the order of addition.

  PCC: precipitated calcium carbonate, SST: cationic swollen starch, AMP: anionic micropolymer

  The tensile value is the geometric mean from the machine and transverse directions.

(Example 7)
The microscopic image in FIG. 6 illustrates how the starch granules swell and how the viscosity increases until it begins to decrease due to breakage of the swollen starch granules. These images show samples of potato starch at 25 ° C, 56 ° C, 60 ° C, 66 ° C, and 95 ° C.

  For the purposes of the present invention, the swollen starch has a large swollen granule as seen in the 66 ° C image after the majority of the granules begin to swell as shown in the 56 ° C image. Mention the state up to the point where it is still visible. Thus, along with microscopic images, the viscosity curve can be used to determine when the starch is sufficiently swollen for use in preparing the filler suspension of the present invention. The maximum viscosity region in FIG. 5 is where most of the starch granules are swollen but not broken. The temperature range within which useful swollen starch granules can be obtained is in the range extending +/− 10 ° C. from the peak region of FIG. Preferably, the temperature at which the raw starch suspension is heated to produce swollen starch is between the peak temperature of FIG. 5 and the peak temperature + 10 ° C., where all starch granules are swollen, And all unswelled granules are eliminated.

(Example 8)
The handmade paper making process was similar to that previously described.
The raw materials used in making this sheet were:

  Fiber: 100% eucalyptus was used as the pulp and was beaten to a SR value of 30 (at 20 ° C.) using a Valley Beater lab beater.

  Filler: Specialty Minerals Inc. Precipitated calcium carbonate (ALBACAAR® LO PCC), average particle size 2.1 μm. The PCC content in the sheet varied between 20.4% and 25.5% by weight. The PCC was used 1) not pretreated, 2) pretreated using swollen starch only, and 3) pretreated with anionic micropolymer and raw starch.

  Starch used for PCC pretreatment: Cationic corn starch, which was used in two ways:

  1. Prepared by mixing water and dry cationic starch powder to make a 3% solids slurry and used as such a slurry with co-additives, the starch was in granular form.

  2. A 3% starch slurry was initially prepared by mixing water and dry starch powder, and the slurry was then used as swollen starch by heating to 77 ° C. with mixing. PCC pretreatment with swollen starch was performed by mixing PCC and swollen starch 5 kg / paper tn at 20% solids.

  Co-additives used for PCC pretreatment with raw starch granules: anionic polymer (Telioform® M305, registered trademark of BASF, commercialized as “micropolymer”). The PCC treatment was performed by first mixing PCC and Telioform®, followed by the addition of cold feed starch slurry. The amount of Telioform® M305 was 0.04 kg / tn paper. The amount of raw material cationic starch was 5 kg / tn paper.

    Internal starch: cationic corn starch. The dried starch powder was mixed with water until a 1% solids slurry was reached, which was then digested at 97 ° C. with mixing. The cooked cationic starch was used in 8 kg / tn paper as internal starch by mixing it with pulp furnish.

  Retention modifier: An additional 0.15 kg / paper tn of cationic polyacrylamide (CPAM) and 1.5 kg / paper tn of silica were used for retention.

  As shown in FIG. 7, PCC pretreatment with swollen starch improves paper strength compared to paper made without such pretreatment.

  Further improvements can be achieved by using anionic micropolymers to improve the interaction between cationic starch and cationic PCC. The cationic starch can even be raw as shown in the examples. Similar behavior is seen in the stiffness in FIG.

Example 9
The 0.3% stock is mixed with pulp furnish, followed by pre-treated PCC (or standard PCC without any pre-treatment in the case of baseline) and internal cationic starch. Prepared by. Retention modifier was added to the stock before forming the paper sheet. An 80 g / m ² wood-free handsheet was made using a dynamic sheet former (DSF) followed by dynamic sheet pressing and then dried at 120 ° C. Prior to paper testing, the paper sheet was calendered under the same conditions and then placed under conditions of 50% relative humidity and 22 ° C.

  The raw materials used in making this sheet were:

  Fiber: 100% eucalyptus was used as the pulp and was beaten to a SR value of 30 (at 20 ° C.) using a Valley Beater lab beater.

  Filler: Specialty Minerals Inc. Precipitated calcium carbonate (ALBACAAR® LO PCC), average particle size 2,3 μm. The amount of filler in the sheet was adjusted to two levels of 20% and 25% by weight.

  Swelled starch used for PCC pretreatment: cationic corn starch. The swollen starch was prepared by mixing water and dry cationic starch powder to make a 3% solids slurry, which was then heated to 75 ° C. with mixing. Cationic swollen starch was used for PCC pretreatment by mixing 5 kg of PCC and swollen starch / paper tn at 20% solids. Some filler samples were only pretreated with swollen starch, and some were pretreated with swollen starch and co-additives.

  Co-additives used for PCC pretreatment with swollen starch: PCC treatment was performed by mixing PCC with swollen starch and co-additives. Different order of addition and co-additive amounts were used. The amount of starch swollen was always fixed at 5 kg / tn of paper. The mixing time for each component was 1 minute. The co-additives tested were: carboxymethylcellulose (CMC), polyacrylic acid, soy polymer and nanocellulose.

  Internal starch: cationic corn starch. The dried starch powder was mixed with water to obtain a 1% solids slurry, which was then digested at 97 ° C. with mixing. The cooked cationic starch was used at 8 kg / paper tn as the internal starch by mixing it with the pulp furnish.

  Retention modifier: An additional 0.2 kg / paper tn of cationic polyacrylamide (CPAM) was used for retention.

  Table 3 shows the improvement in tensile strength achieved by the PCC filler pretreatment as compared to baseline conditions without any PCC treatment. The PCC filler was either pretreated only with swollen starch or pretreated with swollen starch and additional co-additives. Tensile strength comparisons were made at equal ash levels.

Using the technique previously described, treatment of swollen starch alone gave an average improvement of 7.4% in tensile strength compared to the baseline without PCC treatment. By using additional co-additives such as carboxymethylcellulose or polyacrylic acid with swollen starch, the tensile strength can be improved slightly, as shown in Table 3. The use of nanocellulose as a co-additive in PCC treatment of swollen starch can significantly improve strength properties, as shown in Table 3.

  PCC: precipitated calcium carbonate, SST: cationic swollen starch

  The value of specific tensile strength is the geometric mean from the machine direction and the cross direction.

(Example 10)
The 0.5% stock is mixed with pulp furnish, followed by pre-treated PCC (or standard PCC without any pre-treatment in the case of baseline) and internal cationic starch. Prepared by. Retention modifier was added to the stock before forming the paper. 80 g / m ² wood-free handmade paper was made using a Formax sheet former followed by dynamic sheet pressing and then dried at 120 ° C. Prior to paper testing, the paper sheet was placed under conditions of 50% relative humidity and 23 ° C. and was calendered initially from both sides at 180 psi and then from both sides at 220 psi.

  The raw materials used in making this sheet were:

  Fiber: 100% eucalyptus was used as the pulp and was beaten to a SR value of 30 (at 20 ° C.) using a Valley Beater lab beater.

  Filler: Specialty Minerals Inc. Precipitated calcium carbonate (ALBACAAR® LO PCC), average particle size 2,3 μm. The amount of filler in the sheet was adjusted to two levels of 20% and 25% by weight.

  Swelled starch used for PCC pretreatment: cationic corn starch. The swollen starch is prepared by mixing water and dry cationic starch powder to make a 1% solids slurry, which is then heated to 75 ° C under mild mixing in a starch digester. It was. Cationic swollen starch was used for PCC pretreatment by mixing 5 kg of PCC and swollen starch / paper tn at 20% solids. Some filler samples were only pretreated with swollen starch, and some were pretreated with swollen starch and co-additives.

Co-additives used for PCC pretreatment with swollen starch: PCC treatment was done by mixing PCC with swollen starch and co-additives at a temperature of 55 ° C. Different order of addition and co-additive amounts were used. The mixing time for each component was 1 minute. After all ingredients were mixed with PCC, the blend was heated to 70 ° C. under constant low shear mixing.
Co-additives tested: anionic aluminum hydroxide, natural rubber, silica, bentonite, polyvinyl alcohol (PVA), PVAm, biopolymers and some anionic polymers.

  Internal starch: cationic corn starch. The dried starch powder was mixed with water to obtain a 0.5% solids slurry, which was then cooked at 95 ° C. with low mixing in a starch digester. The cooked cationic starch was used at 8 kg / paper tn as the internal starch by mixing it with the pulp furnish. In one of the examples, cooked cationic starch was used at 5 kg / tn for PCC pretreatment instead of swollen starch. Processing of the digested starch was performed with and without co-additives.

  Retention modifier: An additional 0.2 kg / paper tn of cationic polyacrylamide (CPAM) was used for retention.

(Example 11)
The method of Example 10 was followed.

Different order of addition of PCC, swollen starch and co-additive was tested on a laboratory scale. PCC treatment is either by mixing the swollen starch first with PCC and then with the co-additive, or by mixing the co-additive first with PCC and then with the swollen starch. It was conducted.

The lab-scale results shown in Table 4 show that similar intensity increases can be achieved independent of the order of addition when the same co-additive and the same chemical dose are used. As can be appreciated, there is no difference whether PCC is treated with initially swollen starch or with a co-additive.

  PCC: precipitated calcium carbonate, SST: cationic swollen starch

(Example 12)
The method of Example 10 is followed.

  Table 5 shows the improvement in tensile strength achieved by the PCC filler pretreatment as compared to baseline conditions without any PCC treatment. The PCC filler was either pretreated only with swollen starch or pretreated with swollen starch and additional co-additives. Comparisons were made at equal ash levels.

When the previously described Example 10 technique was used, treatment of swollen starch only resulted in an average 9.2% improvement in tensile strength compared to baseline without filler pretreatment. Gave. By introducing the co-additive into the filler pretreatment with the swollen starch, the strength outcome has progressed from a slight improvement to a greater than double improvement, as shown in Table 5.

  PCC: precipitated calcium carbonate, SST: cationic swollen starch

(Example 13)
The method of Example 10 was followed.

  PCC pre-treatment may be performed with cooked starch instead of swollen starch, but the strength results with cooked starch are significantly greater than the strength results with swollen starch. Low. Table 6 shows the results of treating the PCC with only the swollen starch and the result of treating with the cooked starch only. In either case, 5 kg / tn starch was used. Treatment of the swollen starch gave a 13% improvement in tensile strength, whereas the cooked starch gave a 3% improvement at equal ash levels.

Similar to the treatment of swollen starch, the processing of the cooked starch filler can be improved by using co-additives, as shown in Table 6. Depending on the dose, the outcome can be doubled compared to the digested starch treatment alone.

  PCC: precipitated calcium carbonate

    All patents and patent applications cited herein are hereby incorporated by reference as if each individual patent and patent application was clearly and individually described herein.

  Although the claimed invention has been described in terms of various embodiments, those skilled in the art will recognize that various changes, substitutions, omissions and changes may be made without departing from the spirit of the invention. Therefore, it is intended that the scope of the invention be limited only by the scope of the following claims, including equivalents thereof.

One aspect of the present invention is a paper product comprising the above pulp furnish.
For example, the present invention provides the following.
(Item 1)
A filler suspension for use in papermaking comprising:
Filler particles;
Ionic starch,
A complementary ionic co-additive,
A filler suspension.
(Item 2)
The filler particles are clay, talc, synthetic silicate, sodium magnesium aluminosilicate, sodium aluminosilicate, heavy calcium carbonate (GCC), chalk, precipitated calcium carbonate (PCC), heavy calcium sulfate (GCS), precipitated calcium sulfate. Item 4. The filler suspension of item 1, selected from the group consisting of (PCS), titanium dioxide, and combinations thereof.
(Item 3)
Item 2. The filler suspension according to Item 1, wherein the ionic starch is a raw material starch.
(Item 4)
Item 2. The filler suspension according to Item 1, which is an ionic starch in which the ionic starch is swollen.
(Item 5)
Item 2. The filler suspension according to Item 1, wherein the ionic starch is a digested ionic starch.
(Item 6)
Item 2. The filler suspension according to Item 1, wherein the ionic starch is cationic.
(Item 7)
Item 2. The filler suspension according to Item 1, wherein the ionic starch is anionic.
(Item 8)
Item 2. The filler suspension according to Item 1, wherein the ionic starch is amphoteric.
(Item 9)
The ionic starch is selected from the group consisting of corn starch, rice starch, potato starch, cassava starch, tapioca starch, waxy corn starch, wheat starch, sorghum starch and waxy sorghum starch; Item 9. The filler suspension according to any one of items 1 to 8.
(Item 10)
Item 5. The filler suspension of item 4, wherein the swollen ionic starch is formed by heating an aqueous suspension of the raw starch at a gel point temperature of the raw starch of ± 10 ° C.
(Item 11)
Item 4 wherein the swollen ionic starch is formed by heating an aqueous suspension of the raw starch in a temperature range from the gel point temperature of the starch to the gel point temperature of the starch + 10 ° C. A filler suspension according to claim 1.
(Item 12)
12. Filler suspension according to any one of items 1 to 6 and 8 to 11, wherein the complementary ionic co-additive is an anionic flocculant.
(Item 13)
Item 13. The filler suspension of item 12, wherein the anionic flocculant comprises a copolymer of acrylamide and sodium acrylate.
(Item 14)
14. Packing according to item 13, wherein the complementary ionic co-additive is selected from the group consisting of NALCO61815, Nalco61816, Nalco61830, Fennosil® ES210, Fennosil® ES211, Teleioform® M305 Material suspension.
(Item 15)
Item 12. The filler suspension of any one of items 1 to 6 and 8 to 11, wherein the complementary ionic co-additive is an anionic inorganic microparticle.
(Item 16)
Item 16. The filler suspension according to Item 15, wherein the anionic inorganic particles are selected from the group consisting of bentonite, colloidal silica, sodium borosilicate, aluminum hydroxide, or a combination thereof.
(Item 17)
Item 12. The filler suspension of any one of items 1 to 11, wherein the complementary ionic co-additive is nanocellulose.
(Item 18)
Item 12. The filler suspension of any one of items 1 to 6 and 8 to 11, wherein the complementary ionic co-additive is polyvinyl alcohol.
(Item 19)
Item 12. A filler suspension according to any one of items 1 to 11, wherein the complementary ionic co-additive is anionic PVAm or amphoteric PVAm.
(Item 20)
Item 12. The filler suspension of any one of items 1 to 11, wherein the complementary co-additive is a biopolymer.
(Item 21)
Item 21. Filler suspension according to item 20, wherein the biopolymer is based on starch.
(Item 22)
Item 22. The filler suspension of item 21, wherein the starch-based biopolymer is EcoSphere (R) 2202 binder.
(Item 23)
Item 12. The filler suspension of any one of items 1 to 6 and 8 to 11, wherein the complementary ionic co-additive is an anionic polyacrylamide or a sodium salt of polyacrylic acid.
(Item 24)
Item 12. The filler suspension of any one of items 1 to 11, wherein the complementary ionic co-additive is a natural polymer.
(Item 25)
25. A filler suspension according to item 24, wherein the natural polymer is selected from the group consisting of carboxymethylcellulose, natural rubber, soy polymer, or combinations thereof.
(Item 26)
26. A filler suspension according to any one of items 1 to 25, wherein the filler particles are precipitated calcium carbonate.
(Item 27)
27. A pulp furnish comprising pulp fibers and a filler suspension according to any one of items 1 to 26.
(Item 28)
Selected from the group consisting of sizing agents, dry strength agents, wet strength agents, retention modifiers and other functional chemicals (eg optical brighteners, dyes, deforming agents, biosides and combinations thereof) 28. A pulp furnish according to item 27, further comprising additives to be added.
(Item 29)
29. A paper product comprising the pulp furnish of item 27 or item 28.

Claims (29)

A filler suspension for use in papermaking comprising:
Filler particles;
Ionic starch,
A complementary ionic co-additive,
A filler suspension.   The filler particles are clay, talc, synthetic silicate, sodium magnesium aluminosilicate, sodium aluminosilicate, heavy calcium carbonate (GCC), chalk, precipitated calcium carbonate (PCC), heavy calcium sulfate (GCS), precipitated calcium sulfate. The filler suspension according to claim 1, selected from the group consisting of (PCS), titanium dioxide and combinations thereof.   The filler suspension according to claim 1, wherein the ionic starch is a raw material starch.   The filler suspension according to claim 1, wherein the ionic starch is swelled ionic starch.   The filler suspension according to claim 1, wherein the ionic starch is a digested ionic starch.   The filler suspension according to claim 1, wherein the ionic starch is cationic.   The filler suspension according to claim 1, wherein the ionic starch is anionic.   The filler suspension according to claim 1, wherein the ionic starch is amphoteric.   The ionic starch is selected from the group consisting of corn starch, rice starch, potato starch, cassava starch, tapioca starch, waxy corn starch, wheat starch, sorghum starch and waxy sorghum starch; The filler suspension according to any one of claims 1 to 8.   The filler suspension according to claim 4, wherein the swollen ionic starch is formed by heating an aqueous suspension of the raw starch at a gel point temperature of the raw starch of ± 10 ° C.   The swollen ionic starch is formed by heating an aqueous suspension of the raw starch in a temperature range from the gel point temperature of the starch to the gel point temperature of the starch + 10 ° C. 4. Filler suspension according to 4.   12. Filler suspension according to any one of claims 1 to 6 and 8 to 11, wherein the complementary ionic co-additive is an anionic flocculant.   13. A filler suspension according to claim 12, wherein the anionic flocculant comprises a copolymer of acrylamide and sodium acrylate.   14. The complementary ionic co-additive is selected from the group consisting of NALCO61815, Nalco61816, Nalco61830, Fennosil (R) ES210, Fennosil (R) ES211, Telioform (R) M305. Filler suspension.   12. The filler suspension according to any one of claims 1 to 6 and 8 to 11, wherein the complementary ionic co-additive is an anionic inorganic microparticle.   16. The filler suspension according to claim 15, wherein the anionic inorganic particles are selected from the group consisting of bentonite, colloidal silica, sodium borosilicate, aluminum hydroxide, or combinations thereof.   The filler suspension according to any one of claims 1 to 11, wherein the complementary ionic co-additive is nanocellulose.   12. Filler suspension according to any one of claims 1 to 6 and 8 to 11, wherein the complementary ionic co-additive is polyvinyl alcohol.   The filler suspension according to any one of claims 1 to 11, wherein the complementary ionic co-additive is anionic PVAm or amphoteric PVAm.   12. The filler suspension according to any one of claims 1 to 11, wherein the complementary co-additive is a biopolymer.   21. Filler suspension according to claim 20, wherein the biopolymer is based on starch.   The filler suspension according to claim 21, wherein the starch-based biopolymer is EcoSphere® 2202 binder.   12. The filler suspension according to any one of claims 1 to 6 and 8 to 11, wherein the complementary ionic co-additive is an anionic polyacrylamide or a sodium salt of polyacrylic acid.   The filler suspension according to any one of claims 1 to 11, wherein the complementary ionic co-additive is a natural polymer.   25. The filler suspension according to claim 24, wherein the natural polymer is selected from the group consisting of carboxymethylcellulose, natural rubber, soy polymer, or combinations thereof.   26. A filler suspension according to any one of claims 1 to 25, wherein the filler particles are precipitated calcium carbonate.   A pulp furnish comprising pulp fibers and a filler suspension according to any one of claims 1 to 26.   Selected from the group consisting of sizing agents, dry strength agents, wet strength agents, retention modifiers and other functional chemicals (eg optical brighteners, dyes, deforming agents, biosides and combinations thereof) 28. The pulp furnish of claim 27, further comprising an additive that is added.   A paper product comprising the pulp furnish of claim 27 or claim 28.

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