KR20150063561A - Filler suspension and its use in the manufacture of paper - Google Patents

Abstract

There is provided herein a filler suspension comprising ionic starch, a complementary ionic co-additive and filler particles. Paper comprising pulp furnish, including pulp suspension, and pulp furnish, is also provided. Methods for making filler suspensions and methods for their use in the manufacture of paper are also provided.

Description

FILLER SUSPENSION AND ITS USE IN THE MANUFACTURE OF PAPER BACKGROUND OF THE INVENTION < RTI ID = 0.0 > [0001]

The present invention relates to a filler suspension comprising filler particles, an ionic starch and a complementary ionic coadditive. Methods of using the suspensions for the production of paper furnishes and methods of making paper from the furnish are also provided.

In the production of filled paper, a filler slurry is typically added to the pulp suspension prior to sending the pulp suspension to a forming section of a paper-making machine. A retention aid or retention system comprising several components is generally added to the pulp / filler suspension to form what is referred to as a "paper" in the papermaking field, thereby retaining the filler in the resulting paper sheet.

Adding fillers to paper can provide a number of improvements in sheet properties, including improved opacity, brightness, texture, and print clarity. Further, when the filler is cheaper than the pulp, the cost is reduced by adding the filler to the sheet. This savings can be significant when replacing costly chemical pulp fibers with low cost fillers such as precipitated calcium carbonate (PCC). In addition, the rechargeable paper may be easier to dry than paper without the filler, and as a result, the paper machine can be operated more quickly with less steam consumption, which can further reduce costs and improve productivity .

However, for a given sheet weight, there is a limit to the amount of filler that can be added. Along with the papermaker efficiency, the paper force generated is a major factor limiting filler content, but other factors such as retention, drainage and sizing are also considerations.

There is a need for an efficient retention system for making paper with high filler content. Retention agents should provide good filler retention under high shear and turbulence in the papermaking process and should improve drainage without compromising consistency. Retention chemicals are generally added to the furnish before the head box of the paper machine or at the head box entrance. The retention agent is typically a one-, two-, or three-component chemical additive that improves filler and fine-fiber fines retention by bridging and / or flocculation mechanisms. The chemical helps to attach the filler particles and fine fiber segments (tiny fibrous fragments) to the long fibers, or to cause their entanglement to larger aggregate particles that are more easily retained in the web. In order to cause adhesion and agglomeration, the chemical must be adsorbed to the surface of the filler, fine fiber powder and fibers. The degree of adsorption and adhesion of the chemical depends on many factors, including furnish cleanliness and furnish chemistry, the nature of the added chemical, the shear rate in the papermaking process, and the contact time between the retention agent and the furnish component get affected.

The on-going industry trend is to further reduce the cost by increasing the filler content in the paper. However, by replacing fibers with fillers, the paper stock is reduced because not only are there fewer fibers in the sheet, but also because the presence of the filler reduces the contact between the remaining fibers . The filler particles do not bond between themselves and the location of the filler particles in the fiber-fiber bond region prevents hydrogen bonding between the pulp fibers. As a result, a large amount of filler produces a weaker sheet that can be more easily broken in paper mills, size presses, coaters, winders and printing presses. The weaker fiber-to-fiber bond also reduces the surface force of the paper, causing a decrease in pick resistance and an increase in linting. Poor bonding of the filler particles in the fibrous structure may also increase dust in the printing chamber.

Generally, clay, ground calcium carbonate (GCC), precipitated calcium carbonate (PCC), chalk, talc, titanium dioxide, ground calcium sulphate (GCS) and precipitated calcium sulphate ), All of which are commonly used in paper making, are known to damage paper strength and increase the need for chemicals. Fillers with a high surface area have a significant negative impact on the intellect and increase the chemical demand for additives used for intellect, sizing and retention. Because of its shape and narrow particle size distribution, PCC has an open structure that tends to reduce the bond in the sheet than other conventional padding fillers such as chalk, GCC, and clay, . As the filler content in the furnish increases, the demand for sizing chemicals such as alkylketene dimer (AKD) and alkenyl succinic anhydride (ASA) increases to maintain the desired degree of sizing / water repellency. This is because an unbalanced fraction of the sizing chemical is adsorbed on the filler particles. Recently, many papermaking factories that manufacture wood-containing papers have converted to neutral papermaking, allowing the use of hypochlorite calcium carbonate fillers such as GCC and PCC. However, the major concerns about the use of calcium carbonate in these grades of paper still remain in the fields of retention, sheet holding and printing operations.

Another ongoing industry trend is to reduce sheet grammage to reduce costs. Unfortunately, as the basis weight is reduced, almost all paper properties, including opacity, bending stiffness, and permeability limiting factors, are degraded. The reduction in basis weight also reduces the retention of the filler during the papermaking process and can increase the frequency of sheet breakage on the paper machine and during conversion and printing. To overcome the loss of sheet opacity, the paper maker may add more high opacity filler, but this can further degrade sheet strength. The industry requires cost-effective techniques for producing lightweight papers having excellent filler retention and drainage and acceptable paper strength, consistency, optical properties and printing properties.

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

In terms of the present invention, the filler particles may be selected from the group consisting of clay, talc, synthetic silicate, sodium magnesium aluminosilicate, sodium aluminosilicate, heavy calcium carbonate (GCC), chalk, precipitated calcium carbonate (PCC) , Precipitated calcium sulfate (PCS), titanium dioxide, and combinations thereof.

In the context of the present invention, the ionic starch is a raw starch.

In the context of the present invention, the ionic starch is a swollen ionic starch.

In the context of the present invention, ionic starches are cooked ionic starches.

In the context of the present invention, the ionic starch is cationic.

In the context of the present invention, the ionic starch is anionic.

In the context of the present invention, the ionic starch is amphoteric.

In an aspect of the present invention, 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 starch.

In the context of the present 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 at +/- 10 ° C.

In the aspect of the present invention, the swollen ionic starch is formed by heating an aqueous suspension of the raw starch at a temperature ranging from a gelation point temperature of the starch to a gelation point temperature of the starch + 10 ° C.

In the context of the present invention, the complementary ionic co-additive is an anionic flocculant.

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

In terms of the present invention, the complementary ionic co-additives are selected from the group consisting of NALCO 61815, Nalco 61816, Nalco 61830, Fennosil ES210, Fennosil ES211, Telioform M305.

In the context of the present invention, the complementary ionic co-additives are anionic inorganic microparticles.

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

In the context of the present invention, the complementary ionic co-additive is nanocellulose.

In the context of the present invention, the complementary ionic co-additive is polyvinyl alcohol.

In the context of the present invention, the complementary ionic co-additive is anionic or ampholytic PVAm.

In the context of the present invention, the complementary auxiliary additive is a biopolymer.

In terms of the present invention, the biopolymer is a starch based biopolymer.

In the aspect of the invention, starch-based raw polymer is EcoSphere ^® 2202 binder.

In the context of the present invention, the complementary ionic co-additive is an anionic polyacrylic acid or a sodium salt of polyacrylic acid.

In terms of the present invention, the complementary ionic co-additive is a natural polymer.

In terms of the present invention, the natural polymer is selected from the group consisting of carboxymethylcellulose, natural gum, soybean polymer, or combinations thereof.

In the context of the present 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 the context of the present invention, the pulp furnish may comprise a sizing agent, a dry strength agent, a wet strength agent, a retention agent; And other functional chemicals such as optical brighteners, dyes, defoamers, biocides, and combinations thereof.

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

Figure 1 is a schematic diagram of a papermaking process in which an ionic starch, a complementary ionic co-additive, and filler particles are essentially simultaneously added to an aqueous medium.
Figure 2 is a schematic diagram of a papermaking process in which a complementary ionic co-additive is premixed with an ionic starch in an aqueous medium prior to the addition of filler particles.
Figure 3 is a schematic diagram of a papermaking process in which a complementary ionic co-additive is premixed with filler particles in an aqueous medium prior to the addition of ionic starch.
Figure 4 is a schematic diagram of a papermaking process in which an ionic starch is premixed with filler particles in an aqueous medium prior to the addition of a complementary ionic co-additive.
Figure 5 is a graph of the viscosity response of potato starch when heated to a gelling temperature and above a gelling temperature.
Figure 6 includes a microscopic image of potato starch granules as they are heated at various temperatures in water.
Figure 7 is a graph showing the tensile strength of paper sheets prepared using various filler compositions including the filler composition of the present invention.
Figure 8 is a graph showing the stiffness of a paper sheet made using various filler compositions including the filler composition of the present invention.
A brief description of the table
Table 1 shows a comparison of paper sheet properties in paper made using a filler composition comprising swollen cationic starch and a swollen cationic starch + anionic micropolymer co-additive.
Table 2 shows a comparison of paper sheet properties in paper made using a filler composition in which the components of the filler composition were added in different addition orders.
Table 3 shows a comparison of the tensile strength improvements of paper made with PCC filler treated with swollen cationic starch alone and with paper made with PCC filler treated with swollen cationic starch and ancillary additives.
Table 4 shows a comparison of paper tensile index (%) / fracture length improvements according to the order of addition of swollen starches and various auxiliary additives to PCC.
Table 5 shows a comparison of tensile strength improvements over non-PCC treated baseline in paper as a result of various PCC treatments.
Table 6 shows a comparison of paper properties using a filler composition comprising PCC treated with swollen cationic starch, or treated with cooked cationic starch, or treated with a cooked cationic starch and various auxiliary additives.

Argument

Use of the singular forms herein is meant to include plural forms, and vice versa, unless expressly stated otherwise. That is, "a" and "the" denote one or more of any of the words that the word modifies. For example, "a lightly cross-linked polymer" encompasses one such polymer, two such polymers, or even a greater number of such polymers under the right circumstances. For the same reasons, without limitation, a word such as "sizing agent " may refer to a number of such agents or simply one such agent, unless it is clearly stated or evident from the context in which it is not intended.

Without limitation, words of approximation such as " about, "" substantially," " essentially, "and" approximately, " do. The extent to which the description can vary will depend on how large the change can be set and will allow the skilled artisan to recognize that the trait is still the necessary traits and capabilities of the unmodified trait . In general, except for the subject matter of the preceding discussion, the values explicitly stated or implied herein, which are modified by words of approximation, may vary from the specified value by +/- 15%.

Composition

In one embodiment of the invention, a filler suspension for use in papermaking is provided, comprising a liquid vehicle, typically filler particles in water, ionic starch and a complementary ionic co-additive.

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

In yet another aspect, 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 making paper from the furnish. Other anionic and cationic agents may be added to the furnish to enhance retention and improve drainage. As noted above, the furnish may also contain other papermaking preparations such as those known to those skilled in the art.

The present invention also provides a starch / supplementary additive composition for forming a filler suspension and a method of making a combination thereof with filler particles.

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

As used herein, "raw" starch refers to starch that is not hydrolyzed or steamed enough to swell or cook as in the conditions described below.

As used herein, "swollen" starches represent water-absorbing or bio-starch granules that are swollen to a state in which they are no longer capable of further absorbing water, preferably without rupturing the swollen granules at this time . Exemplary swollen starches suitable for use in the present filler suspensions are described in U.S. Patent Nos. 7,074,845; 7,625, 962; And 8,354,004, each of which is incorporated herein by reference as if set forth fully herein.

Generally, the preparation of swollen starches requires careful, controlled swelling under temperature and time conditions. Other important parameters include slurry pH, consistency and mixing. The control parameters will vary depending on the starch type and are typically determined empirically for each type of starch prior to use in mill-scale paper production. The general process is to suspend the bio-ionic starch in cold water and then heat the suspension until the starch is swollen. The swollen starches can then be mixed with the complementary ionic auxiliary additives and filler particles in any desired order, i. E., All ingredients can be added at essentially the same time, or two of the ingredients can be premixed, The ingredients may be added to form a filler suspension. For example, in Figure 1, the swollen ionic starch 1, the complementary ionic auxiliary additive 8a and the filler particles 2 are mixed together in a mixer 4 to form a filler suspension, , Where it is mixed with the pulp fibers 3 to form a furnish. In Figure 2, the swollen ionic starch 1 and the complementary ionic auxiliary additive 8a are premixed and then this combination is mixed with the filler particles 2 in the mixer 4, The suspension is mixed with the pulp fibers (3) in a mixer (5). In Figure 3, the complementary ionic auxiliary additive 8a is premixed with the filler particles 2, the mixture is mixed with the ionic starch 1 in the mixer 4, and the formed filler suspension is mixed with the mixer 5 ), Which is then mixed with the pulp fibers 3 to form a furnish. 4, the ionic starch 1 and the filler particles 2 are pre-mixed in a mixer 4 and the pre-mix is transferred to a mixer 5, and the complementary ionic supplement additive 8a is essentially mixed Is added to the premix between the mixer (4) and the mixer (5). In each of these situations, the furnish containing the filler suspension is subsequently transferred to the paper machine 6 with optional additives 7 to form the paper 9. During the paper drying operation, the suspended swollen starch granules rupture, liberating amylopectin and amylose macromolecules, which act to combine the solid components of the sheet.

A "cooked" starch as used herein refers to a starch heated to a temperature above its gelation point and maintained until the starch granules are swollen and essentially all swollen granules are ruptured.

The combination of ionic starch, ionic co-additive and filler particles may be used in papermaking under acidic, neutral or alkaline conditions. The composition is mainly used to ensure that the filler and starch have a minimal negative effect on sheet strength and are well retained on the paper sheet during the papermaking process. The use of ionic starch / ionic co-additive / filler particle compositions tends to cause greater intellectivity than using starch or ancillary additives alone with filler particles.

Filler

The filler particles may be any of those known to those skilled in the art, and the filler suspension may comprise a single filler or one or more fillers. The filler particles are typically inorganic materials having an average particle size in the range of 0.5 to 30 占 퐉, more typically 1 to 10 占 퐉, such as, without limitation, clay, heavy calcium carbonate (GCC), chalk, precipitated calcium carbonate ), Talc, heavy calcium sulfate (GCS) and precipitated calcium sulfate (PCS), titanium dioxide, synthetic silicate, sodium magnesium aluminosilicate, sodium aluminosilicate and blends thereof. The pulp slurry to which the filler suspension is added may be comprised of mechanical pulp, chemical pulp, recycled pulp, and mixtures thereof.

Starch

Suitable starches for use in the present invention include, but are not limited to, corn, waxy corn, potato, wheat, tapioca, sorghum, rice bran and rice starch. The starch may be cationic, anionic or amphoteric; Each of these forms is well known in the art and is generally commercially available. By way of non-limiting example, the starch may be made cationic by including a quaternary ammonium cation in the starch, and may be made anionic by including a carboxyl or sulfonic acid group in the starch, and the starch comprising the combination Can be made amphoteric by making it. All of these ionic starch forms are well known to those skilled in the paper art and are not further described herein.

Starch granules are insoluble in cold water. To disperse or "cook" the starch, the starch is heated in an aqueous suspension. As the heating progresses, the starch granules are first subjected to a slightly reversible swelling step until they reach a critical temperature of "pasting", "gelatinization" or simply "gel" temperature, A large amount of swelling occurs, resulting in a large increase in viscosity. If maintained at a gel temperature or higher for a sufficient period of time, the viscosity returns to a lower level due to rupture of the swollen granules. Each of the various starches has its own gel temperature. The gel temperature for many starches is available in the existing literature or can be readily determined empirically by heating the desired starch suspension while monitoring the viscosity. The swollen starch granules are different from cooked starches. The cooked starch is caused when the swollen starch granules rupture at temperatures above the gel temperature to release amylose and amylopectin dissolved in the aqueous medium.

By carefully controlling the treatment of a particular starch, it can be swollen or cooked. With respect to the swollen starch, depending on the starch source, the final particle size of the swollen starch granules ranges from about 25 [mu] m to about 100 [mu] m. Representative but non-limiting examples of the manufacture of swollen starches are shown in the examples.

Auxiliary additives

The auxiliary additive is included in the filler suspension to improve the effect of the ionic starch in improving the properties of the filler paper by modification of the filler suspension. The auxiliary additives may be cationic, anionic or amphoteric. It is selected to have a net charge complementary to the net charge of the ionic starch. "Complementary" means that if the starch is cationic, the anionic additive is preferred in the present invention and vice versa. If the starch is bilaterally, the auxiliary additive may be cationic, anionic or self-amphoteric. Anionic auxiliary additives include, but are not limited to, carboxymethylcellulose, nano-cellulose, polyacrylic acid, alginate, colloidal silica, bentonite, polyacrylamide, natural gum and soluble soap. The cationic co-additives include, but are not limited to, polyethyleneimine, chitosan, polyvinylamine, poly (dadmac), polyacrylamide, alum, trivalent and tetravalent cations. Soybean polymers may also be used as auxiliary additives. One or more auxiliary additives may be used with the particular starch and filler.

Non-limiting examples of amphoteric auxiliary additive suitable as a co-additive for use in a filler suspension of the present invention is the Ashland-Hercules Hercobond ^® 1303.

Other materials suitable for use as auxiliary additives in the filler suspensions of the present invention include Eka NP ^® 090, Eka NP ^® 200, Eka NP ^® 320, Eka NP ^® 32K, Eka NP ^® 442, Eka NP ^® 590/670, Eka NP ^® 780, Eka NP ^® 882, Eka NP ^® 890 and EKA NP ^® 2180 (both manufactured by AkzoNobel); Is an anionic colloidal silica nanoparticle, such as but not limited to Fennosil ^® 525 (Kemira) and POSITEK ^® 8699 (Nalco).

To the sodium borosilicate nanoparticles (typically from 1 to 100nm in size) of ^{Nalco Ultra POSITEK ® 8692, 8693,} BD420 and TR420 used as an auxiliary additive in the filler suspension of the present invention are also suitable.

Altonite ( ^R ) S & B Industrial Minerals, Fennolite ( ^R ) LF5 (Kemira) and Hydrocol (R) (BASF) are bentonites suitable for use as auxiliary additives in the filler suspensions of the present invention.

Anionic aluminum hydroxide microparticles are also considered suitable for use as auxiliary additives in the filler suspensions of the present invention.

The Hercules Incorporated (now Ashland-Hercules) anion from acrylic amide copolymer Perform SP ^® 7200 and 9232 are also suitable for use as an auxiliary additive in the filler suspension of the present invention. Perform ^® 7200 is issued as dated 12 February 2007 MSDS 999 1060 1076, Ver. 3 < / RTI >

Telioform ^® M305, a copolymer of sodium acrylate and acrylamide dispersed in mineral oil, as described in the MSDS published March 23, 2006, by Ciba Specialty Chemicals Corporation (now BASF), is also used in the filler suspensions of the present invention ≪ / RTI > Other Telioform ^® compositions such as, but not limited to, Telioform ^® M100, M135, M200, M300, S10, M100A, M8A and SC22 may also be suitable for use as auxiliary additives in the filler suspensions of the present invention.

^{Fennosil ® ES-210, Fennosil ®} ES-211 ( both of acrylamide / acrylic acid copolymer should by default) and Fennosil ^® ES-325 anionic forms exemplified by; And Fennosil ^® E130 (formulations containing acrylamide / p- amine), E128 (polyacrylamide / polydimethyl diallyl ammonium chloride (DADMAC) dosage form comprising the copolymer), the ES-325 (polyacrylamide / salt the dosage form) and E-126 (acrylamide / p- amine) additives of Fennosil ^® class containing the cationic form is exemplified comprising also suitable as an auxiliary additive in the filler suspension of the present invention.

Nanocellulose, such as those described in WO 2007/091942 and WO 2009/126106, both of which are incorporated herein by reference, are also suitable as ancillary additives for use in the filler suspensions of the present invention can do.

Still other materials contemplated in the present invention that are suitable for use as auxiliary additives in the filler suspensions of the present invention include cellulosic materials and derivatives such as Engineered Cellulose Additive (ECA) from AkzoNobel; Noil fibril as described in U.S. Patent No. 6,156,118, which is incorporated by reference as if fully set forth herein; Hemicellulose and hemi-cellulosic-containing materials.

Carboxymethylcellulose (CMC) is also suitable as an auxiliary additive in the filler suspensions of the present invention.

Natural gums such as guar and xanthan are also suitable auxiliary additives in the filler suspensions of the present invention.

Another material contemplated herein for use as an auxiliary additive suitable for use in the filler suspensions of the present invention is the glyoxylated DADMAC / acrylamide copolymer compositions NALCO 64110, 64114 and 64170, NALCO 61815, 61816 and 61830, which are anionic flocculants that are copolymers of acrylamide and sodium acrylate, as generally described in U.S. Patent No. 8,088,213, which is incorporated by reference herein.

Still other materials suitable for use as an auxiliary additive in the filler suspension of the present invention is the Ashland ^Hercules-® Hercobond HA5305 and SP7200 and Eka PL8660.

Polyvinyl alcohol (PVA) is also suitable for use as an auxiliary additive in the filler suspensions of the present invention.

Amphoteric polyvinylamines (PVAm), and amphoteric polyvinylamines such as, but not limited to, amphoteric copolymers of vinylformamide, vinylamine and acrylic acid, are also suitable as ancillary additives in the filler suspensions of the present invention, non-limiting examples are XELOREX F3000 ^® from BASF.

Biopolymers can also be used as auxiliary 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 may be a micro- or nano-particulate. Raw polymer comprises EcoSphere ^® 2202 from the binder material in which Ecosynthetix Burlington, Ontario, Canada, but are not limited to.

If the co-additive is a polymer, it may be non-crosslinked, slightly crosslinked, or highly crosslinked.

The auxiliary additive may be water soluble or insoluble. Non-limiting examples of water-soluble auxiliary additive is a polyacrylamide based anionic polymer, Telioform ^® M303.

The polymeric co-additive may be a micropolymer. As used herein, "micropolymer" refers to polymer particles obtained by emulsion curing, dispersion polymerization and water-in-water polymerization, wherein the reaction of the water soluble monomers is carried out with polyamines such as DADMAC or DIMAPA But are not limited to, coagulant. The micropolymer can be "structured ", i.e., the individual polymer strands within the polymer particles can adopt a stable three-dimensional structure.

"Lightly crosslinked" means that the crosslinked polymer remains fairly water-soluble. That is, a slightly crosslinked polymer appears more like a "branched" polymer than a fully crosslinked polymer in which the polymer chains become inseparable and become insoluble in water. As used herein, slightly cross-linked and side chains are used interchangeably to denote crosslinked but still water soluble polymers. Examples of anionic, branched, water-soluble polymers are described in U.S. Patent Nos. 5,958,188, 6,391,156 B1, 6,395,134 B1, 6,406,593 B1 and 6,454,902 B1, each of which is incorporated herein by reference as if fully set forth herein have.

"Heavily crosslinked" refers to a polymer that is not only water-soluble when not crosslinked or slightly crosslinked, but is no longer water-soluble as a result of crosslinking.

Filler / ionic starch / ionic auxiliary additive suspension

Generally, the suspension contains from 60 to 99.5% by weight of filler, from 35 to 0.499% by weight of ionic starch, based on the total solids content of the filler particles, the ionic starch and the complementary ionic auxiliary additive, Starch and 5.0 to 0.001% by weight of a complementary ionic co-additive.

It is understood that the suspension contains a complex of ionic starch and a complementary ionic co-additive, but may also contain a free ionic starch and a free ionic co-additive.

Paper formulations

The compositions, suspensions, and furnishings of the present invention may include sizing agents such as alkyl ketene dimers, alkenyl succinic anhydrides and rosins; Wet and dry strength enhancers, and conventional paper formulations, such as, but not limited to, cationic or anionic polymeric retention agents. The composition may be a single chemical, such as anionic microparticles (colloidal silicic acid, bentonite), anionic polyacrylamides, cationic polymers (cationic polyacrylamides, cationic starches), dual chemical systems (Cationic polymer / anionic microparticle / anionic polymer, cationic polymer / anionic microparticle / anionic polymer), or a three component system (cationic polymer / anionic microparticle / anionic microparticle, cationic polymer / anionic polymer) Lt; / RTI > The choice of retentive chemicals and when they are added in the paper-making process will depend on the nature of the ionic charge of the treated filler slurry, the paper making furnace, and the shear forces that occur in the paper making process.

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

The paper sheet made with the filler suspension according to the present invention may exhibit a greater internal bond strength, as measured by the Scott bond technique, than the control sheet produced without filler treatment . At the same filler content, the wet and dry strength properties of the sheet produced using the filler suspensions herein may be greater than the wet and dry strength characteristics of the sheet made with the filler alone.

The use of the filler suspensions of the present invention allows the use of coated paper such as coated and uncoated fine paper, super-calendered paper and newsprint with minimal loss of intelligence and excellent optical properties And produce it. Thus, using the filler suspensions of the present invention, papermakers are allowed to produce filler paper having a higher filler content in the paper sheet. In general, the potential benefits from the use of the treated filler suspensions of the present invention include improved sizing, wet grip strength, dry grip strength and printability, and / or reduced use of expensive reinforcing chemical pulp fibers.

Under certain conditions, a combination of ionic starch and ionic co-additives may be used to fortify non-filler-free papers, such as sack paper and cardboard products.

Example

The embodiments provided below are merely intended to assist in understanding various aspects of the present invention. They should not be construed or interpreted as limiting the scope of the invention in any way.

General description

In the following examples, the results were obtained using laboratory scale techniques.

If the starch to be used is a raw starch, the starch may be suspended in water, or the starch may be suspended in water and heated to a temperature sufficiently lower than its gelation point to such an extent that the starch is swollen to a significant degree or not cooked .

On the other hand, if swollen starches are required, the raw starch present in the aqueous slurry, typically at 0.5 to 20% solids at room temperature, is added to a batch cooker, jet cooker ), Or may be swollen by mixing with hot water. A preferred method is to swell the granules by mixing the 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 method for producing a swollen starch for the purpose of the present invention.

Example  One

The biodegradable starch dispersion in cold water is heated to a temperature that is approximately the gelation point of a particular starch to swell it. When the starch is swollen, a complementary co-additive is added and the mixture is added to the stirred filler suspension.

Example  2

The starch dispersion is first swollen, then it is added to the stirred filler suspension and then the auxiliary additive is introduced. In this method, the starch powder is dispersed in cold water and then mixed with hot water or heated to a temperature approximately equal to the starch gelling point. The swollen starch is then quickly mixed with the filler suspension at a temperature below the starch gelling point, and then the auxiliary additive is added.

Example  3

The starch dispersion is first swollen and then added to the stirred auxiliary 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 that is approximately the gelation temperature of the particular starch. The swollen starch is then quickly mixed with the filler suspension.

The combination of swollen starch, co-additives and filler is carried out under good mixing conditions. During the preparation of the starch / supplementary additive / filler suspension another additive is added to form a complex with the filler, followed by the addition of swollen starch and ancillary additives.

The treated filler suspension can be introduced directly into the pulp slurry or, optionally, before the sheet joining process, for example in a blend chest, in a machine chest or at the inlet of the fan pump, Diluted and added to the paper mill pulp stock. Generally, the treated filler suspensions tend to retain their agglomeration properties over time when added to paper pulp slurries. (Anionic polyacrylamide), a cationic polymer (cationic polyacrylamide, cationic starch) and anionic polymers such as anionic microparticles (colloidal silica, bentonite, organic micropolymer), anionic polymers The capacity of the same retention agents can be increased.

Example  4

The internal cationic starch was mixed with the pulp furnish, then mixed with the pretreated PCC, and finally mixed with the retention agent to produce a 0.3% strength stock. A dynamic sheet pressing (DSF: dymanic sheet former) was used followed by drying at 120 ° C to produce a 80g / m 2 wood-free water handsheet. Prior to the paper test, the paper sheet was calendered under the same conditions and then conditioned at 50% relative humidity (RH) and 22 < 0 > C.

The raw materials used in sheet manufacture were as follows:

Fiber : 100% eucalyptus used as pulp, calibrated at SR 30 (at 20 ° C) using a Valley Beater lab refiner.

Filler : precipitated calcium carbonate (ALBACAR ^® LO PCC, manufactured by Specialty Minerals Inc.), average particle size 2.3 μm. The PCC content in the sheet varied from 19.3 to 25.9% by weight.

Swollen used in the pretreatment PCC Cationic starch : Cationic potato starch. The anhydrous cationic starch powder was mixed with water to prepare a 3% solid slurry and then heated to 63 캜 under mixing to prepare a swollen cationic starch. The swollen cationic starch was used in the PCC pretreatment by mixing 5 kg of swollen cationic starch per ton of paper with 20% solids PCC. Some filler samples were pretreated with only swollen cationic starch, and some were pretreated with swollen starch and anionic auxiliary additives.

Swollen Auxiliary used for the pre-treatment with PCC and cationic starch additive: anionic micro-polymer (TELIOFORM M305 ^®, a registered trademark of BASF). Treatment of PCC was performed by mixing the swollen cationic starch and anionic micropolymer with PCC. The different addition orders were used and the swollen cationic starch capacity was fixed at 5 kg / tonne of paper, while the anionic micro polymer capacity was 0.05% by weight of the material / anhydrous PCC as supplied, and the material / anhydrous PCC 0.1% by weight.

Internal starch : cationic potato starch. The anhydrous starch powder was mixed with water so that it became a 1% solid slurry and then cooked at 97 캜 under mixing. The cooked cationic starch was mixed with pulp furnish and used at 8 kg per ton of paper.

Retention : 0.2 kg of cationic polyacrylamide (CPAM) per tonne of paper was used for retention.

Example  5

Table 1 shows the properties of sheets made with PCC treated with swollen starch and with PCC treated with anionic micropolymer followed by swollen starch. The anionic micro polymer capacity was 0.05-0.1% by weight of the substance / anhydrous PCC as received. Sheets with anionic micropolymers in the PCC pretreatment exhibit superior intellectual properties - tensile, internal bonding, bending stiffness - compared to PCC treated with swollen starch alone. The best intellectual performance was achieved by 0.1% anionic micropolymer capacity. This allowed a 6% unit filler increase without loss of inelastic properties.

The tensile and stiffness values are the geometric mean from the machine direction and from the cross direction.

Example  6

Table 2 shows the PCC treated with swollen starch alone and the PCC treated with swollen starch and anionic micropolymer using different addition orders (PCC treated with swollen starch followed by anionic micropolymer, and PCC) paper sheet treated with an anionic micro polymer followed by a swollen starch. The presence of the anionic micropolymer improves the paper properties of the sheet made of PCC treated with swollen starch, regardless of the order of addition.

The tensile values are the geometric mean from the machine direction and the direction of the span.

Example  7

The microscope images of FIG. 6 illustrate how the starch granules were swollen and how much the viscosity increased until the viscosity began to decrease due to rupture of the swollen starch granules. These images show samples of potato starch at 25 캜, 56 캜, 60 캜, 66 캜 and 95 캜.

For purposes of the present invention, the swollen starches exhibit a state in which most of the granules begin to swell, as shown in the image at 56 DEG C, until the time when the large swollen granules are still visible, as shown in the image at 66 DEG C . Thus, along with microscopic images, a viscosity curve can be used to determine when the starch is swollen enough to be used in the preparation of the filler suspensions of the present invention. The maximum viscosity region in Fig. 5 is a region where most of the starch granules are swollen but not ruptured. The temperature range over which useful swollen starch granules can be obtained is the range extending from the peak area +/- 10 DEG C of FIG. Preferably, the temperature at which the raw starch suspension is heated to produce swollen starches is from the peak temperature of Figure 5 to the peak temperature of Figure 5 + 10 ° C, where all starch granules are swollen and all non- Removed.

Example  8

The manufacturing process of the water base paper was similar to that described above.

The raw materials used for sheet manufacture were as follows:

Fiber : 100% eucalyptus used as pulp, calibrated at SR 30 (at 20 ° C) using a Belly Bitter Wrap separator.

Filler: precipitated calcium carbonate with a mean particle size 2.1㎛ (ALBACAR ^® LO PCC) (manufacturer: Specialty Minerals Inc.). The PCC content in the sheet varied from 20.4 to 25.5% by weight. PCC is used by 1) pretreating without any pretreatment, 2) pretreated with only swollen starch, and 3) pretreated with anionic micropolymer and raw starch.

Starch used in PCC pretreatment : Cationic corn starch used in two ways:

1. Prepared by mixing anhydrous cationic starch powder with water to make a 3% solids slurry, which itself is used in combination with ancillary additives, the starch being in granular form.

2. A 3% starch slurry is first prepared by mixing anhydrous starch powder with water and then used as swollen starch by heating the slurry to 77 ° C with mixing. PCC pretreatment with swollen starch was performed by mixing 5 kg of swollen starch per tonne of paper with PCC in 20% solids.

Secondary additives used in PCC pretreatment to raw starch granules : anionic polymers (Telioform ^® M305, trademark from BASF, sold as "micropolymer"). The treatment of PCC was performed by first mixing Telioform ^® with PCC and then adding cold starch slurry. Telioform ^® M305 capacity was 0.04 kg per ton of paper. The biocompatible starch capacity was 5 kg per ton of paper.

Internal starch : cationic corn starch. Anhydrous starch powder was mixed with water to reach a 1% solids slurry and then cooked at 97 ° C under mixing. The cooked cationic starch was mixed with pulp furnish and used as internal starch at 8 kg per ton of paper.

Retention agent : 0.15 kg of cationic polyacrylamide (CPAM) per ton of paper and 1.5 kg of silica per ton of paper were used for retention.

As shown in FIG. 7, PCC pretreatment with swollen starch improves paper holding power compared to paper prepared without such pretreatment.

Additional improvements can be achieved by using the anionic micropolymer to enhance the interaction between the cationic starch and the cationic PCC. The cationic starch may even be a raw starch as shown in the examples. A similar behavior can be seen in the stiffness of FIG.

Example  9

The internal cationic starch was mixed with the pulp furnish followed by the pretreated PCC (or, in the case of the baseline standard, PCC without any pretreatment) to produce a 0.3% concentration of stock. Before pasting the paper sheet, a retention agent was added to the stock. A dynamic sheet press machine (DSF) was followed by dynamic sheet pressing followed by drying at 120 DEG C to produce a 80 g / m < 2 > wood-free water pond. Prior to the paper test, the paper sheet was calendered under the same conditions and then conditioned at 50% RH and 22 < 0 > C.

The raw materials used in sheet manufacture were as follows:

Fiber : 100% eucalyptus used as pulp, calibrated at SR 30 (at 20 ° C) using a Belly Bitter Wrap separator.

Fillers: The mean particle size of the precipitated calcium carbonate 2.3㎛ (ALBACAR ^® LO PCC) (manufactured; Specialty Minerals Inc.). The amount of filler in the sheet was adjusted to two levels, 20 wt% and 25 wt%.

Swelled starch used in PCC pretreatment : cationic corn starch. The anhydrous cationic starch powder was mixed with water to prepare a 3% solids slurry and then heated to 75 캜 under mixing to produce swollen starches. Cationically swollen starches were used for PCC pretreatment by mixing 5 kg of swollen starch per tonne of paper with 20% solids PCC. Some filler samples were pretreated with swollen starch only, and some were pretreated with swollen starch and ancillary additives.

Auxiliary additives used in PCC pretreatment with swollen starches : The treatment of PCC was carried out by mixing the swollen starches and auxiliary additives with PCC. Different addition orders and amounts of auxiliary additives were used. The amount of swollen starch was kept fixed at 5 kg per ton of paper. The mixing time for each component was 1 minute. The supplementary additives tested were carboxymethylcellulose (CMC), polyacrylic acid, soybean polymer and nanocellulose.

Internal starch : cationic corn starch. Anhydrous starch powder was mixed with water to obtain a 1% solid slurry and then cooked at 97 캜 under mixing. The cooked cationic starch was used as an internal starch at 8 kg / tonne of paper by mixing into pulp furnish.

Retention agent : 0.2 kg of cationic polyacrylamide (CPAM) per tonne of paper was additionally used for retention.

Table 3 shows the tensile strength improvement achieved with PCC filler pretreatment compared to baseline conditions without any PCC treatment. The PCC filler was pretreated with swollen starch alone or pre-treated with swollen starch and additional auxiliary additives. The tensile strength comparison is performed at the same ash level.

Using the technique described above, it was found that, with swollen starch treatment alone, the tensile strength was improved by an average of 7.4% compared to the baseline without PCC treatment. By using a swollen starch such as carboxymethyl cellulose or polyacrylic acid and an additional co-additive, the tensile strength can be slightly improved as shown in Table 3. [ The use of nanocellulose as an auxiliary additive in the swollen starch PCC treatment can significantly improve the grip strength characteristics, as shown in Table 3.

The tensile rate values are the geometric mean from the machine direction and the width direction.

Example  10

The internal cationic starch was mixed with pulp furnish followed by pretreated PCC (or, in the case of baseline standards, PCC without any pretreatment) to produce a 0.5% concentration of stock. Before adding the paper, a retention agent was added to the stock. A Formax sheet jumper was followed by dynamic sheet pressing followed by drying at 120 ° C to produce a 80 g / m 2 wood-free water jumper. Prior to the paper test, the paper sheet was conditioned at 50% RH and 23 DEG C, calendered first at 180 psi from both sides, and calendered on both sides at 220 psi.

The raw materials used for sheet manufacture were as follows:

Fiber : 100% eucalyptus used as pulp, calibrated at SR 30 (at 20 ° C) using a Belly Bitter Wrap separator.

Fillers: The mean particle size of the precipitated calcium carbonate 2.3㎛ (ALBACAR ^® LO PCC) (manufactured; Specialty Minerals Inc.). The amount of filler in the sheet was adjusted to two levels, 20 wt% and 25 wt%.

Swelled starch used in PCC pretreatment : cationic corn starch. The anhydrous cationic starch powder was mixed with water to make a 1% solids slurry and then heated in a starch cooker to 75 < 0 > C under mild mixing to make swollen starches. Cationically swollen starches were used for PCC pretreatment by mixing 5 kg of swollen starch per tonne of paper with 20% solids PCC. Some filler samples were pretreated with swollen starch only, and some were pretreated with swollen starch and ancillary additives.

Auxiliary additives used in PCC pretreatment with swollen starches : The treatment of PCC was carried out by mixing the swollen starches and auxiliary additives with PCC at a temperature of 55 ° C. Different addition orders and amounts of auxiliary additives were used. The mixing time for each component was 1 minute. After mixing all ingredients with PCC, the blend was heated to 70 ° C under constant low shear mixing.

Ancillary additives tested : anionic aluminum hydroxide, natural gum, silica, bentonite, polyvinyl alcohol (PVA), PVAm, biopolymers and some anionic polymers.

Internal starch : cationic corn starch. Anhydrous starch powder was mixed with water to obtain a 0.5% solid slurry, which was then cooked at 95 캜 under low mixing in a starch cooker. The cooked cationic starch was used as an internal starch at 8 kg / tonne of paper by mixing into pulp furnish. In one of the examples, the cooked cationic starch instead of the swollen starch was used at 5 kg / tn for PCC pretreatment. Cooked starch treatment was carried out in the presence and absence of auxiliary additives.

Retention : In addition, 0.2 kg of cationic polyacrylamide (CPAM) per ton of paper was used for retention.

Example  11

The procedure of Example 10 was followed.

Different addition orders for PCC, swollen starch and co-additives were tested on a laboratory scale. The PCC treatment was carried out by first mixing the swollen starch with the PCC and then mixing with the auxiliary additive, or by first mixing the auxiliary additive with the PCC and then mixing with the swollen starch.

The laboratory scale results shown in Table 4 show that similar enhancement can be achieved regardless of the order of addition when the same auxiliary additives and the same chemical doses are used. As can be seen, there is no difference whether the PCC is first treated with swollen starch or with an auxiliary additive.

Example  12

The procedure of Example 10 was followed.

Table 5 shows the improvement in tensile strength achieved with PCC filler pretreatment compared to baseline conditions without any PCC treatment. The PCC filler was pretreated with swollen starch alone or with pretreated swollen starch and additional ancillary additives. The comparison is performed at the same batch level.

Using the technique of Example 10 described above, the swollen starch treatment alone improved the tensile strength by 9.2% on average compared to the baseline without filler pretreatment. By introducing an auxiliary additive into the filler pretreated with the swollen starch, the improvement in the glutinous performance was improved from a slight improvement level to more than two times as shown in Table 5.

Example  13

The procedure of Example 10 was followed.

PCC pretreatment may be performed using cooked starches instead of swollen starches, but the performance of the nutrients with cooked starches is significantly lower than with the swollen starches. Table 6 shows the results when PCC was treated with only swollen starch and only with cooked starch. In both cases, 5 kg / tn starch was used. The swollen starch treatment improved the tensile strength by 13%, while the cooked starch provided 3% improvement at the same batch level.

Similar to the swollen starch treatment, the cooked starch filler treatment may be improved by using ancillary additives as shown in Table 6. Depending on the capacity, the performance can be doubled compared to the cooked starch treatment alone.

All patents and patent applications cited in this specification are herein incorporated by reference as if each individual patent and patent application were specifically and individually indicated to be fully incorporated herein by reference.

While the claimed subject matter is described in terms of various aspects, one skilled in the art will recognize that various modifications, substitutions, omissions, and variations can be made without departing from the spirit thereof. Accordingly, the scope of the subject matter is intended to be limited only by the following claims, including equivalents.

Claims (29)

A filler suspension for use in papermaking, comprising filler particles, an ionic starch and a complementary ionic coadditive. The method of claim 1, wherein the filler particles are selected from the group consisting of clay, talc, synthetic silicate, sodium magnesium aluminosilicate, sodium aluminosilicate, ground calcium carbonate (GCC), chalk, precipitated calcium carbonate wherein the filler suspension is selected from the group consisting of calcium carbonate, ground calcium sulphate (GCS), precipitated calcium sulphate (PCS), titanium dioxide, and combinations thereof. The filler suspension of claim 1, wherein the ionic starch is a raw starch. The filler suspension of claim 1, wherein the ionic starch is a swollen ionic starch. The filler suspension of claim 1, wherein the ionic starch is cooked ionic starch. The filler suspension of claim 1, wherein the ionic starch is cationic. The filler suspension of claim 1, wherein the ionic starch is anionic. 2. The filler suspension of claim 1, wherein the ionic starch is bilateral. 9. The method according to any one of claims 1 to 8, wherein 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, ≪ / RTI > The filler suspension according to claim 4, wherein the swollen ionic starch is formed by heating an aqueous suspension of raw starch at a gelation point temperature of the raw starch of 占 占 폚. The filler suspension according to claim 4, wherein the swollen ionic starch is formed by heating an aqueous suspension of raw starch at a temperature ranging from a gelation point temperature of the starch to a gelation point temperature of the starch + 10 ° C. 12. A filler suspension according to any one of claims 1 to 6 and 8 to 11, wherein the complementary ionic auxiliary additive is an anionic flocculant. 13. The filler suspension of claim 12, wherein the anionic flocculant comprises a copolymer of acrylamide and sodium acrylate. 14. The filler suspension of claim 13, wherein the complementary ionic auxiliary additive is selected from the group consisting of NALCO 61815, Nalco 61816, Nalco 61830, Fennosil ES210, Fennosil ES211, Telioform M305. 12. A 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 micro-particle. 16. The filler suspension of claim 15, wherein the anionic inorganic particles are selected from the group consisting of bentonite, colloidal silica, sodium borosilicate, aluminum hydroxide or combinations thereof. 12. A filler suspension according to any one of claims 1 to 11, wherein the complementary ionic co-additive is nanocellulose. 12. A filler suspension according to any one of claims 1 to 6 and 8 to 11, wherein the complementary ionic auxiliary additive is polyvinyl alcohol. 12. A filler suspension according to any one of claims 1 to 11, wherein the complementary ionic auxiliary additive is anionic or amphoteric PVAm. 12. A filler suspension according to any one of claims 1 to 11, wherein the complementary auxiliary additive is a biopolymer. 21. The filler suspension of claim 20, wherein the biopolymer is a starch based biopolymer. 22. The filler suspension of claim 21, wherein the starch based biopolymer is an EcoSphere 2202 binder. 12. A filler suspension according to any one of claims 1 to 6 and 8 to 11, wherein the complementary ionic co-additive is an anionic polyacrylic acid or a sodium salt of polyacrylic acid. 12. A 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 of claim 24, wherein the natural polymer is selected from the group consisting of carboxymethylcellulose, natural gum, soybean polymer, or combinations thereof. 26. The filler suspension according to any one of claims 1 to 25, wherein the filler particles are precipitated calcium carbonate. A pulp furnish comprising a pulp fiber and a filler suspension of any one of claims 1 to 26. 28. The composition of claim 27, further comprising a sizing agent, a dry strength agent, a wet strength agent, a retension aid, And an additive selected from the group consisting of optical brighteners, dyes, defoamers, biocides, and other functional chemicals such as combinations thereof. 28. A paper product comprising the pulp furnish of claim 27 or 28.

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