WO2001051707A1 - Utilisation de sols inorganiques dans la fabrication du papier - Google Patents

Utilisation de sols inorganiques dans la fabrication du papier Download PDF

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Publication number
WO2001051707A1
WO2001051707A1 PCT/US2000/034488 US0034488W WO0151707A1 WO 2001051707 A1 WO2001051707 A1 WO 2001051707A1 US 0034488 W US0034488 W US 0034488W WO 0151707 A1 WO0151707 A1 WO 0151707A1
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WIPO (PCT)
Prior art keywords
polymer
cationic
molecular weight
sol
acrylamide
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PCT/US2000/034488
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English (en)
Inventor
Jose M. Rodriguez
Craig W. Vaughan
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Calgon Corporation
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Priority to AU2001224398A priority Critical patent/AU2001224398A1/en
Publication of WO2001051707A1 publication Critical patent/WO2001051707A1/fr

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Classifications

    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H21/00—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties
    • D21H21/06—Paper forming aids
    • D21H21/10—Retention agents or drainage improvers
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
    • D21H17/20—Macromolecular organic compounds
    • D21H17/21—Macromolecular organic compounds of natural origin; Derivatives thereof
    • D21H17/24—Polysaccharides
    • D21H17/28—Starch
    • D21H17/29—Starch cationic
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
    • D21H17/20—Macromolecular organic compounds
    • D21H17/33—Synthetic macromolecular compounds
    • D21H17/34—Synthetic macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
    • D21H17/41—Synthetic macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds containing ionic groups
    • D21H17/42—Synthetic macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds containing ionic groups anionic
    • D21H17/43—Carboxyl groups or derivatives thereof
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
    • D21H17/20—Macromolecular organic compounds
    • D21H17/33—Synthetic macromolecular compounds
    • D21H17/34—Synthetic macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
    • D21H17/41—Synthetic macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds containing ionic groups
    • D21H17/44—Synthetic macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds containing ionic groups cationic
    • D21H17/45—Nitrogen-containing groups
    • D21H17/455—Nitrogen-containing groups comprising tertiary amine or being at least partially quaternised
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
    • D21H17/63—Inorganic compounds
    • D21H17/67—Water-insoluble compounds, e.g. fillers, pigments
    • D21H17/675—Oxides, hydroxides or carbonates
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H21/00—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties
    • D21H21/50—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties characterised by form
    • D21H21/52—Additives of definite length or shape
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H23/00—Processes or apparatus for adding material to the pulp or to the paper
    • D21H23/76—Processes or apparatus for adding material to the pulp or to the paper characterised by choice of auxiliary compounds which are added separately from at least one other compound, e.g. to improve the incorporation of the latter or to obtain an enhanced combined effect
    • D21H23/765—Addition of all compounds to the pulp

Definitions

  • the invention relates to an improved retention and dewatering system in the paper aking process. More particularly, the invention relates to the use of a microparticle system including an inorganic sol and one or more polymers, such as a coagulant polymer, a polyampholyte polymer, and a high molecular weight water soluble flocculant polymer, in the cellulosic paper slurry to bring about improvements in retention, drainage, and sheet formation.
  • a microparticle system including an inorganic sol and one or more polymers, such as a coagulant polymer, a polyampholyte polymer, and a high molecular weight water soluble flocculant polymer
  • a dilute aqueous composition known as a "furnish” or “stock” is sprayed onto a screen or moving mesh known as a "wire”.
  • Solid components of the composition such as cellulose fibers and inorganic particulate filler material, such as titanium dioxide, kaolin clay, and calcium carbonate, are drained or filtered by the wire to form a paper sheet.
  • the percentage of solid material retained on the wire is known as the "first pass retention" of the papermaking process .
  • Drainage is the rate of removal of water from the furnish as the paper sheet is formed. Drainage usually refers to water removal that takes place in the "drainage zone" (gravity and vacuum sections) of the Fourdrinier-.or twin wire paper machine primarily before any pressing of the wet paper web subsequent to formation of the sheet.
  • drainage aids help to drain the water from the fibrous web in the papermaking process, and are used to improve the overall efficiency of dewatering in the production of paper products in the papermaking process.
  • Retention aids function to increase the amount of fillers remaining in the fibrous web. Retention is believed to be a function of different mechanisms, such as filtration by mechanical entrainment, electrostatic attraction, and bridging between the fibers and the fillers in the furnish.
  • Formation relates to the uniformity of the paper or paperboard sheet produced from the papermaking process. Formation is generally evaluated by the variance in light transmission through a paper sheet. A high variance is generally indicative of "poor” formation and a low variance is indicative of "good” formation. Generally, as the retention level increases, the level of formation generally decreases from good formation to poor formation . Retention, drainage, and formation properties of the final paper or paperboard sheet are particularly desirable to paper producers for several reasons, the most significant of which is productivity. Good retention and good drainage will enable a paper machine to run faster and to increase production. Good sheet formation improves sheet quality. These improvements are realized by the use of retention and drainage aids.
  • retention and drainage aids are additives which are used to flocculate the fine solids present in the furnish to improve retention and drainage in the papermaking process.
  • the use of such additives is limited by the effect of flocculation on the formation of the paper sheet. As more retention aid is added so the size of the aggregates of fine solid material is increased, a variation in density and visible non- uniformity of the paper sheet can result. Over- flocculation can also affect drainage as it may eventually lead to holes in the sheet and a subsequent loss of vacuum pressure in the later stages of dewatering.
  • Retention and drainage aids are generally added to the furnish as the furnish approaches the headbox of the paper machine and may be one of three types, viz.: (a) single polymers;
  • the present invention relates to the use of a retention and drainage aid of the last type, i.e. a microparticle system.
  • This type generally may give the best results.
  • Microparticle systems generally comprise a polymeric flocculant and a fine inorganic particulate material. The inorganic material improves the efficiency of the flocculant and/or allows smaller, more uniform floes to be produced.
  • Microparticle systems have been described widely in the prior art. Examples of publications of microparticle systems include EP-B-235,893 wherein bentonite is used as the inorganic material in conjunction with a high molecular weight cationic polymer in a specified addition sequence; WO-A-94/26972 wherein a vinylamide polymer is described for use in conjunction with one of various inorganic materials; EP-O-748,897 wherein an aluminum compound, such as polyaluminum chlorides, and an anionic inorganic particle, such as silica sol, are mixed immediately prior to addition to the pulp suspension; and EP-O-355,816 wherein a colloidal alumina sol having a positive surface charge and a colloidal alumina concentration in the range between 0.1 to 1% is added to the furnish along with an anionic polymer flocculant.
  • the colloidal alumina has a particle size in the range between 1-50 nanometers and the colloidal alumina sol is added to the furnish in an amount between about 0.025
  • U.S. Patent No. 4,964,954 discloses the use of a three component system comprising a cationic polymeric synthetic retention agent, an anionic inorganic colloid and a polyaluminum compound.
  • anionic inorganic colloids are colloidal montmorillonite and bentonite, titanyl sulphate sols, silica sols, aluminum modified silica sols or aluminum silicate sols.
  • U.S. Patent Nos. 4,388,150 and 4,980,025 disclose the use of silica-based particles generally supplied in the form of aqueous sols.
  • U.S. Patent No. 4,388,150 discloses in a process for making paper the use of colloidal silicic acid and cationic starch.
  • the cationic starch has a degree of substitution of not less than 0.01 and the weight ratio of cationic starch to Si0 2 is between 1:1 and 25:1.
  • U.S. Patent No. 4,980,025 discloses in a process for making paper the use of cationic polyacrylamide and an aluminum modified silicic acid for improving retention and drainage .
  • Johnson discloses a papermaking process in which a cationic starch, a high molecular weight anionic polymer, and a dispersed silica having a particle size ranging from between about 1-50 nanometers are added to the cellulosic pulp prior to formation of the sheet.
  • Lorz et al. disclose a method for draining a paper stock by using activated bentonite, a cationic polyelectrolyte, and a high molecular weight polymer based on acrylamide or methacrylamide .
  • Johnson discloses the use of a cationic starch having a degree of substitution of at least 0.01, a high molecular weight anionic polymer, and a dispersed silica having a particle size ranging from between about 1-50 nanometers .
  • Larsson discloses the use of colloidal silicic acid and either amphoteric or cationic guar gum that may form part of the binder complex in a mixture with cationic starch.
  • Rushmere discloses a retention and dewatering aid comprising a two component combination of an anionic polyacrylamide and a cationic colloidal silica sol.
  • U.S. Patent No. 4,913,775 disclose a process of making paper or paperboard comprising:, a) passing an aqueous cellulosic suspension through one or more shear stages, b) draining the suspension to form a sheet, and c) drying the sheet. Retention, drainage, drying and formation are achieved by adding to the suspension an excess of high molecular weight linear synthetic cationic polymer before shearing the suspension and adding bentonite after shearing.
  • Rushmere discloses a papermaking process, whereby retention and drainage are improved by the addition of a water soluble polyaluminosilicate microgel and an organic cationic polymer.
  • Rushmere discloses the use of anionic polysilicate microgels with an organic polymer to flocculate pulp and filler fines such that water removal is easier and fines retention is greater.
  • Andersson et al disclose the use of an anionic component consisting of an aluminum silicate or an aluminum-modified silicic acid such that the surface groups of the particles contain silicium and aluminum atoms in a ratio of from 9.5:0.5 to 7.5:2.5.
  • a cationic component consists of cationic carbohydrate having a degree of substitution of 0.01-1.0.
  • Johansson discloses the use of a retention agent, aluminum modified silica, and polyaluminium compound in the production of paper.
  • Reed discloses a process for increasing productivity by adding a water soluble cationic polymer, such as a cationic starch or a substantially linear cationic polymer, before the shearing and an inorganic material such as a colloidal silica or a bentonite after the shearing.
  • a water soluble cationic polymer such as a cationic starch or a substantially linear cationic polymer
  • Derrick discloses the use of colloidal siliceous material, such as swelling, clay, in intimate association with a low molecular weight water soluble high anionic charge density organic polymer, such a polyacrylic acid or polyamine.
  • the colloidal siliceous material is preferably added to the aqueous pulp after the addition of a conventional high molecular weight flocculating agent .
  • Derrick et al disclose the addition to the thin stock of bentonite clay in intimate association with a low molecular weight water soluble anionic charge polymer.
  • a non-ionic high molecular polyelectrolyte is added after the last high shear point.
  • Bixler et al disclose a process for improving the papermaking by the addition of a cationic polymer and natural hectorite to the furnish prior to the headbox.
  • Begala discloses a papermaking process that includes the addition to the papermaking cellulosic slurry first a high molecular weight cationic polymer and then a medium molecular weight anionic polymer such as an ionizable sulfonate.
  • Johansson et al disclose the production of alkali metal or ammonium silica sols and the use of this sol in combination with a cationic polymer in the papermaking process.
  • Rushmere et al disclose an improved method for the production of water soluble polyaluminosilicate microgels and their use in the papermaking process.
  • U.S. Patent No. 5,473,033 disclose a drainage aid comprised of a microparticle and a water soluble cationic polymer selected from a water soluble cationic copolymer composed of the polymerization reaction of an N-vinylamide with at least one cationic quaternary amine monomer.
  • Harrington et al disclose a method of improving the drainage characteristics of a pulp slurry in a papermaking operation utilizing the sequential steps of adding alum, ionic polyacrylamide, and cationic starch.
  • Rushmere et al disclose a process for preparing water soluble polyaluminosilicate and their use in the papermaking process .
  • Moffett discloses an improved method of paper formation by using a combination of polysilicate microgel and anionic and cationic polymers with the optional utilization of an aluminum salt.
  • Begala discloses the use of a cationic and an anionic polymer where the anionic polymer comprises a formaldehyde condensate of a naphthalene sulfonic acid salt.
  • Moffett uses a cationic aluminum compound and an anionic aluminum in conjunction with a cationic polymer and an anionic microparticle, such as a polysilicate microgel or a polyaluminosilicate microgel.
  • Kjell et al disclose the formation of a new silica sol with a high content of microgel which are particularly suitable for use as additives in combination with cationic acrylamide based polymers .
  • inorganic sols such as colloidal silica sols, colloidal aluminum sols, and aluminum silicate sols have been proposed for use in microparticle systems
  • the selection of specific inorganic sols as in the present invention to improve, unexpectedly and beneficially, the performance of the microparticle system has not been considered in the prior art.
  • a method of producing paper includes adding to a paper making stock or furnish a microparticle system retention and/or drainage aid which comprises one or more polymers selected from the group consisting of a high molecular weight water soluble flocculant polymer, a polyampholyte polymer and a coagulant polymer, and an inorganic particulate material comprising an inorganic sol selected from the group consisting of zirconia sol and alumina sol.
  • the zirconia sol can exist in an amorphous form and/or a crystalline form.
  • the alumina sol preferably is an alumina hydrate sol.
  • the microparticle system may also comprise a coagulant comprised of a cationic polymer, a polyampholyte polymer or a polysaccharide, which is added to the stock or furnish.
  • microparticle system comprising a high molecular flocculant and an inorganic sol selected from the group consisting of zirconia sol and alumina sol to improve the retention, drainage and formation properties of a paper or paperboard sheet.
  • Figure 1 illustrates the amorphous form of the zirconia sol of the invention in "A”, and the crystalline form of the zirconia sol of the invention in “B” .
  • paper includes products comprising a cellulosic sheet material including paper sheet, paper board and the like.
  • microparticle system refers to the combination of at least a high molecular weight water soluble polymer used as a flocculant and at least one inorganic sol as the inorganic particulate material.
  • the microparticle system of the invention may further comprise a coagulant that may be either a cationic polymer or a polyampholyte polymer, or a polysaccharide may be added.
  • the components of the microparticle system of the invention may be added simultaneously or sequentially to the furnish at the same or different points of addition but, preferably, added separately in the manner and order described herein below.
  • the present invention relates to a papermaking process in which paper is made by the steps of forming an aqueous cellulosic slurry, subjecting the slurry to at least one shear stage, and draining the slurry to form a paper sheet.
  • the process can be further characterized by unique steps concerning the sequence and point of addition of the components of the microparticle system of the invention.
  • microparticle system of the present invention has been found to be particularly effective in improving the retention and drainage properties of the cellulosic slurry.
  • the polyampholyte polymer is preferably a water soluble polymer having a weight average molecular weight of from about 5,000 to 20 million.
  • the polyampholyte polymer may contain at least one cationic monomer selected from the group consisting of a quaternary dialkyldiallyl ammonium, methacryloyloxyethyl trimethyl ammonium chloride, methacryloyloxythyl trimethyl ammonium methosulfate, acrylamido propyl triethyl ammonium chloride, methacrylamido propyl triethyl ammonium chloride, acryloyloxyethyl trimethyl ammonium chloride, quaternized derivatives of N, N-dimethyl amino ethyl methacrylate, dimethyl amino ethyl acrylate, diethyl amino ethyl acrylate, dibutyl amino ethyl methacrylate, dimethyl amino methyl acrylate,
  • the quaternary dialkyldiallyl ammonium halide monomer is selected from the group consisting of dimethyly diallyl ammonium chloride, diethyl diallyl ammonium chloride, dimethyl diallyl ammonium bromide, and diethyl diallyl ammonium bromide.
  • the vinyl alcohol monomer will most conveniently be generated as a monomer simply by hydrolysis of vinyl acetate.
  • acrylic acid and methacrylic acid may conveniently be introduced into the polymer by hydrolysis of acrylamide and methacrylamide, respectively.
  • the cationic coagulant is preferably a low molecular weight water-soluble polymer positively charged species.
  • the positively charged species may be inorganic or organic.
  • the organic coagulant will be a charged polymer having a weight average molecular weight of at least 2,000, although polymers having weight average molecular weights of 2 million are acceptable.
  • Preferred polymers include epichlohydrin/dimethylamine copolymers, ethylene dichloride/ammonia copolymers, diallyldimethylammonium halide polymers and copolymers, e.g. diallyldimethylammonium chloride polymers and diallyldimethylammonium chloride/acrylamide copolymers, and acrylamido N,N-dimethyl piperazine quaternary/acrylamide copolymers .
  • the cationic high molecular weight water-soluble flocculant polymer may be a copolymer derived from at least one cationic monomer selected from the group consisting of a quaternary dialkyldiallyl ammonium, methacryloyloxyethyl trimethyl ammonium chloride, methacryloyloxyethyl trimethyl ammonium methosulfate, acrylamido propyl trimethyl ammonium chloride, methacrylamido propyl triethyl ammonium chloride, acryloyloxyethyl trimethyl ammonium chloride, quaternized derivatives of N, N-dimethyl amino ethyl methacrylate, dimethyl amino ethyl acrylate, diethyl amino ethyl acrylate, dibutyl amino ethyl methacrylate, dimethyl amino methyl acrylate, dimethyl amino methyl methacrylate, diethyl amino propyl acrylate, die
  • the anionic high molecular weight water soluble polymer is derived from monomers from acrylic acid or its homologues, sodium acrylate, vinyl sulfonic acid, sodium vinyl sulfonate, itaconic acid, sodium itaconate, 2- acrylamido-2methylpropanesulfonic acid sodium salt, acrylamidoglycolic acid, 2-acrylamido-2-methylbutanoic acid, 2-acrylamido-2methylpropanephosphonic acid, sodium vinyl phosphate, allyl phosphonic acid and/or admixtures thereof.
  • This polymer may also be either a hydrolyzed acrylamide polymer or a copolymer of its homologues, such as methacrylamide.
  • the polymer may contain nonionic portions and may contain at least one nonionic monomer from the group of acrylamide, N-vinylamide, N- alkylacrylamide, vinyl acetate, vinyl alcohol, acrylate esters, diacetone acrylamide, and N, N- dimethylacrylamide .
  • Acrylic acid and methacrylic acid may conveniently be introduced into the polymer by hydrolysis of acrylamide and methacrylamide, respectively.
  • the anionic polymer may be a homopolymer, copolymer, or terpolymer.
  • the most preferred high molecular weight terpolymers are acrylic acid/acrylamide/2- acrylamido-2-methylpropane sulfonate; acrylic acid/acrylamide/acrylamido methane sulfonate; acrylic acid/acrylamide/2-acrylamido ethane sulfonate; and acrylic acid/acrylamide/2-hydroxy-3-acrylamide propane sulfonate.
  • Commonly accepted counter ions may be used for the salts, such as sodium ion and potassium ion.
  • the high molecular weight polymer i-s an anionic charge polymer, it is selected from the group consisting of a homopolymer of acrylic acid, a copolymer of acrylic acid/acrylamide, acrylic acid/2-acrylamido-2- methylpropane sulfonate/acrylamide, and a terpolymer of acrylic acid/acrylamide/2-acrylamido-2-methylpropane sulfonate.
  • the inorganic sol used in the invention is selected from the group consisting of a zirconia sol (Zr0 2 ) and an alumina sol.
  • a zirconia sol generally is in both amorphous form and crystalline form, and preferably has a positive charge. These two forms are illustrated in Figures 1A and IB, respectively. In solution, these two forms generally are in equilibrium.
  • the morphology and particle size of the sol can be controlled by manipulating the starting materials and conditions.
  • the particle size of the zirconia sol may range between 5nm to about lOOOnm and, preferably, ranges between about 5nm to about lOOnm.
  • the preferred alumina sol is an alumina hydrate sol.
  • the alumina hydrate sol forms a fibrous micro gel and has a positive charge.
  • the high molecular weight water soluble flocculant polymer employed in the microparticle system of the invention generally is an agent for aggregating the solids into floes in the paper making furnish.
  • fines' means fine solid particles including fine fibers as defined in TAPPI Standard No. T261cm-90 entitled "Fines fraction of paper stock by wet screening”.
  • fines are those particles (including fibers) which will pass through a round hole of 76 micron diameter.
  • flocculation of -the fines of the furnish may be brought about by the high molecular weight water soluble polymer itself or in combination with another agent, e.g. a cationic coagulant such as a cationic polymer, a polyampholyte polymer, or a polysaccharide.
  • the degree of flocculation obtained may be measured indirectly by the improvement in retention and/or drainage obtained. Flocculation of fines gives better retention of the fines in the fiber structure of the forming paper sheet thereby giving improved dewatering or drainage.
  • the floes formed by the high molecular weight water soluble polymer may be subject to a shearing action before addition of the inorganic sol of the microparticle system of the invention.
  • the inorganic, sol may be added prior to or at the same stage as the flocculant polymer.
  • a shearing stage may be applied prior to addition of the polymer, if added prior to the inorganic sol, and before or after addition of the inorganic sol.
  • the method of the invention can give an improved combination of drainage and retention and in some cases drying and formation properties, and it can be used to make a wide range of papers of good formation and strength at high rates of drainage and with good retention.
  • the microparticle system of the method of the invention may also surprisingly and beneficially improve one or more optical properties, e.g. brightness of paper sheets formed using the system in a given cellulosic stock.
  • the method can be operated to give a surprisingly good combination of high retention with good formation. Because of the good combination of drainage and drying it is possible to operate the method at high rates of production and with lower vacuum and/or drying energy than is normally required for papers having good formation.
  • the method can be operated successfully at a wide range of pH values and with a wide variety of cellulosic stocks and pigments.
  • the pH range for the stock in the invention is from about 3 to about 10.
  • the method of the invention can be carried out using any conventional paper making apparatus.
  • the furnish or ⁇ thin stock' that is drained to form the paper sheet is often made by diluting a thick stock which typically has been made in a mixing vessel by blending pigment or filler material, such as one or more of the filler materials conventionally used in the art, appropriate fiber, any desired strengthening agent or other additives, and water. Dilution of the thick stock can be by means of recycled water.
  • the thick stock may be cleaned in a conventional manner, e.g. using a vortex cleaner. Usually the thick stock is cleaned by passage through a centriscreen or pressure screen.
  • the thin stock is usually pumped along the apparatus employed to treat the furnish by one or more centrifugal pumps (transfer or fan pumps) .
  • the thick stock may be pumped to the centriscreen by a first fan pump.
  • the thick stock can be diluted by water to the thin stock at the point of entry to this first fan pump or prior to the first fan pump, e.g. by passing the thick stock and dilution water through a mixing pump.
  • the thick stock may be cleaned further, by passage through a further centriscreen.
  • the thin stock that leaves the final centriscreen may be passed through a second fan pump and/or a head box prior to the sheet forming process.
  • the sheet forming process may be carried out by use of any conventional paper or paper board forming machine, for example, flat wire Fourdrinier, twin wire former or vat former or any combination of these.
  • the high molecular weight water soluble polymer used as a flocculant may be added before the thin stock reaches the last point of high shear, i.e. which generally is a centriscreen, and the resultant stock is preferably sheared, e.g. at the last point of high shear, before adding the inorganic sol.
  • the cationic coagulant or polyampholyte, or polysaccharide is added to the thick stock before its passage to the fan pump prior to the thick stock's passage through the centriscreen.
  • the inorganic sol may be.
  • the cationic coagulant, polyampholyte, or polysaccharide is added to the thick stock before its passage to the fan pump and prior to the thick stock's passage through the centriscreen.
  • the cationic coagulant, polyampholyte or polysaccharide is added to the thick stock prior to a fan pump, the high molecular weight flocculant polymer is added to the thin stock after the stock's passage through the fan pump, and the inorganic sol is added to the thin stock after the stock' s passage through the centriscreen or pressure screen.
  • the high molecular weight flocculant polymer of the microparticle system is added to thin stock (i.e. stock having a solids content of desirably not more than 2% or, at the most, 3% by weight) rather than- to thick stock, whereas the cationic coagulant, polyampholyte or polysaccharide is added to the thick stock.
  • the high molecular weight polymer may be added directly to the thin stock or it may be added to the dilution water that is used to convert thick stock to thin stock.
  • the amount of flocculant polymer added to the stock in the method according to the invention may be any amount sufficient to give a substantial effect in flocculating the solids, especially the fines, present in the stock or furnish.
  • the total amount of flocculant polymer added may be in the range 0.005% to 1% by weight (from about 0.10 to about 20 pounds per ton of furnish), more particularly in the range 0.01% to 0.5% by weight (dry weight of polymer based on the dry weight of solids present in the stock or furnish) or from about 0.2 to about 10 pounds per ton of furnish.
  • the addition may be carried out in one or more doses at one or more addition sites .
  • the total amount of cationic coagulant, polyampolyte, or polysaccharide added may be in the range 0.005 to 0.5% (from about 0.1 to about 10 pounds per ton of furnish), more particularly in the range 0.05% to 0.25% by weight (dry weight of polymer based on the dry weight of solids present in the stock or furnish) or from about 1 to about 5 pounds per ton of furnish.
  • the amount of inorganic sol added to the stock according to the present invention may be in the range 0.005% to 1.0% (from about 0.1 to about 20 pounds per ton of furnish), more particularly in the range 0.05% to 0.5% by dry weight based on the dry weight of solids in the furnish or from about 1 to about 10 pounds per ton of, furnish.
  • the addition of the cationic coagulant, polyampolyte, or polysaccharide and the high molecular weight polymer may cause the formation of large floes of the suspended solids in the stock or furnish to which it is added and these are immediately or subsequently broken down by the high shear (usually in the fan pump and/or centriscreen) to very small floes that are known in the art as " icrofIocs" .
  • the resultant stock is a suspension of these microflocs and the inorganic sol may then be added to it when the microflocs have been formed.
  • the stock is desirably stirred during addition of the inorganic sol sufficiently to distribute the inorganic particulate material uniformly throughout the stock to which it is added.
  • the stock that has been treated with the inorganic sol of the microparticle system of the invention is subsequently subjected to substantial agitation or high shear this will tend to reduce the retention properties but improve still further the formation.
  • the stock containing the inorganic sol could be passed through a centriscreen prior to dewatering and the paper sheet product will then have very good formation properties but possibly reduced retention compared to the results if the inorganic particulate material is added after that centriscreen. Because formation in the final sheet is usually good, in the method of the invention, if the inorganic sol is added just before sheet formation and because it is generally desired to optimize retention, it is usually preferred to add the inorganic sol after the last point of high shear.
  • the high molecular weight flocculant polymer is added just before the final shearing stage, e.g. the final centriscreen and the stock with the high molecular weight flocculant polymer added is led from the final centriscreen to a headbox with the inorganic sol being added either to the headbox or between the centriscreen and the headbox, and the stock is then dewatered to form the paper sheet.
  • an inorganic sol selected from the group consisting of a zirconium sol and an aluminum sol along with a high molecular weight flocculant polymer and either a cationic coagulant, a polyampholyte, or a polysaccharide can increase the drainage and retention, and improve sheet formation in a papermaking process.
  • Examples 1-6 are illustrative of the use of zirconia sols in amorphous and crystalline form, as illustrated in Figures 1A and IB, respectively. As stated hereinabove, these two forms in solution can exist in equilibrium. As stated hereinabove, the morphology and particle size of the sol can be controlled by manipulating the starting materials and conditions.
  • Example 7 is illustrative of the use of an alumina hydrate sol. These sols generally form a fibrous microgel and are positively charged.
  • Examples 1-8 are not intended to limit the scope of the invention in any way.
  • the following products were used: Preparation Of The Polyampholyte Polymer Solution: Product A - polyampholyte copolymer consisting of 50/50 acrylamide/DMDAAC; having a reduced viscosity (dl/g) at 0.05 d/dl in 1 N (unit of concentration) NaCl of 5.6; and being 30.2% active emulsion.
  • Product B polyampholyte copolymer consisting of 50/50 acrylamide/DMDAAC, the acrylamide portion being approximately 5% post-hydrolyzed to acrylic acid; having a reduced viscosity (dl/g) at 0.05 d/dl in 1 N NaCl of 7.9; and being 29.4% active.
  • Product C - polyampholyte copolymer consisting of 50/50 acrylamide/DMDAAC, the acylamide portion being approximately 20% post-hydrolyzed to acrylic acid; having a reduced viscosity (dl/g) at 0.05 d/dl in 1 N NaCl of 9.6; and being 29.1% active.
  • Product D polyampholyte copolymer of acrylamide/DMDAAC which is 8% active and which is commercially available under the tradename ECCat TM 777 from ECC International Inc., GA, U.S.A.
  • the polyampholyte polymer solution of at least Products B - D and Product K was prepared by adding 1 ml of the polyampholyte to 100 ml of tap water. The solution was stirred for 1 hour with a magnetic stirrer.
  • Product F water soluble anionic emulsion polymer being 28% active - commercially available from Calgon Corporation, Pittsburgh, PA under the trademark Hydraid ® 8736 and having a molecular weight ranging between 5 and 15 million.
  • Product G water soluble anionic emulsion polymer being 25% active - commercially available from Calgon Corporation, Pittsburgh, PA under the trademark Hydraid ® 7706 and having a molecular weight ranging between 5 and 15 million.
  • Product H - water soluble anionic emulsion polymer consisting of acrylamide and acrylic acid units and being 30% active - commercially available from Calgon Corporation, Pittsburgh, PA under the trademark Hydraid ® 7736 and having a molecular weight ranging between 5 and 15 million.
  • Product M 100% polyacrylic polymer with a molecular weight of approximately 1 million - manufactured by Chemdal International, an AMCOL International Corporation and available under the trademark RMP ® 100.
  • Product N- - water soluble cationic emulsion polymer being 25% active - AM/AETAC copolymer - commercially available from Calgon Corporation, Pittsburgh, PA under the trademark Hydraid ® 954 and having a molecular weight ranging between 5 and 15.
  • Product O a highly charged cationic copolymer - in an aqueous solution of a cationic copolymer of 50% dimethyl diallyl ammonium chloride and 50% acrylamide having a molecular weight of about 5 x 10 6 - available from Calgon Corporation, Pittsburgh PA under the trademark Merquat® 550.
  • a solution was prepared by adding 2 grams of polymer to 98 ml of water. The polymer solution was stirred for 1 hours. Then 1 ml of the above solution was diluted to 100 ml with deionized water.
  • Product I - cationic starch manufactured by Grain Processing Corporation and available under the tradename CHARGEMASTER R-630.
  • Product J - cationic starch manufactured by A.E.Staley Manufacturing Co., Decatur, IL and available under the trademark STA-LOK ® 400.
  • a solution was prepared by adding 22 grams of starch to 97 ml of deionized water. The starch solution was boiled for one hour.
  • Cellulose fibers 80/20wt% bleached hardwood kraft/bleached softwood kraft.
  • Filler 100 wt % water washed kaolin-grade filler clay processed by ECC International Inc., U.S.A. under the tradename ACME. The amount of filler was 20 wt % based on fiber solids.
  • a dry lap pulp of the fibers was soaked in tepid water for about 10 minutes and then diluted to 2wt% solids in water and refined with a laboratory scale Valley Beater to a Canadian Standard Freeness of 250ml.
  • the filler was added to the refined pulp slurry.
  • the pulp slurry was diluted further with water to approximately 0.5% consistency to form thin stock for testing.
  • the pH of the pulp slurry was 5.8 and then adjusted with caustic to raise the pH to 8.2.
  • zirconia sol containing both amorphous and crystalline forms in equilibrium were used in this Example 1.
  • the zirconia sol was obtained from NYACOL Products, Inc. a Company of PQ Corporation. The product characteristics are given in Table 1.
  • the sols were used "as is” without any further dilution.
  • Zr 10/20 refers to zirconia particles with a mean particle size of lOnm and 20wt % solids in the solution.
  • Zr 50/20 would be zirconia particles having a mean particle size of 50nm and a 20wt% solids in solution, etc.
  • Either a polyampholyte or a cationic coagulant polymer solution was added to one liter of thin stock at 0.5wt% consistency prepared as discussed above in this Example 1.
  • the stock was poured into a (Britt) mixing jar.
  • the contents of the jar were mixed for 10 seconds with a Lightning mixer at a constant speed of 1500 rpm.
  • the slurry was then dosed with either a polyampholyte polymer solution prepared above or the high molecular weight polymer solution prepared above and then stirred for an additional minute.
  • the mixer was then turned off and the slurry was allowed to stand for three minutes.
  • the zirconia sol was added and the pulp slurry was poured back and forth five times between two beakers.
  • the slurry was poured into a Britt drainage jar and shaken three times before allowing the slurry to drain.
  • the drainage water was collected for 30 seconds and weighed by using a tarred beaker.
  • the final pH of the slurry was the pH of the drained water.
  • Either the polyampholyte or cationic coagulant polymer solution was added to one liter of thin stock with the 0.5 wt % consistency prepared above in this Example 1.
  • This slurry was poured into a square (Britt) mixing jar and was mixed for 10 seconds with a Lightning mixer at a constant speed of 1500 rpm.
  • the slurry was then dosed with either the polyampholyte polymer solution as prepared herein above or the high molecular weight flocculant polymer solution prepared above. Stirring was continued for an additional minute.
  • the mixer was then turned off and the slurry was allowed to stand for three minutes.
  • the zirconia sol was added to the slurry and the pulp slurry was poured back and forth five times between two. beakers.
  • the slurry was poured into a Britt drainage jar and shaken three times before allowing it to drain. The first 20 ml were collected. This sample was used in the turbidity measurement.
  • the sample . ..turbidity in NTU' s was measured with a portable turbidity meter (Model 2100P) made by Hach Company.
  • This example used the zirconia sol designated in Table 1 as "Zr 50/20" in the dosage indicated in Tables 2 - 8. All dosages are given in pounds of polymer/zirconia sol per ton of solids based on the dry weight of the solids in the slurry.
  • the order of addition of the components of the microparticle system of the invention to the pulp slurry coincide with the listed order from left to right for each component in the following Tables 2-8, i.e.
  • Product D polyampholyte
  • Product F locculant
  • Example 2 The pulp slurry of Example 2 was similar to that used in Example 1.
  • the order of addition of the components was changed from that of Example 1 in that the zirconia sol was added before the polyampholyte polymer (Product C) was added to the slurry.
  • the listed order of the components in Tables 9 and 10 represents the order of addition of these components of the microparticle system of the invention to the pulp slurry, i.e. zirconia sol was added first, followed by the polyampholyte polymer (Product C) .
  • Example 2 show that again the best turbidity (lowest NTU) and the best drainage (higher ml value) occurred when zirconia sol and a polyampholyte polymer were used regardless of the sequence of addition of these two components of the microparticle system of the present invention (compared to the sequence in Example 1) . These results also show that for these zirconia sols, the sol having a mean particle size of 10 nm (Zr 10/20) was more effective than that having a mean particle size of 50 nm (Zr 50/20) in improving retention but that drainage was comparable.
  • Example 3 This Example 3 illustrates the effects of the use of a cationic starch with a high molecular weight flocculant polymer and the three zirconia sols of Table 1.
  • the pulp slurry was similar to that used in Example 1.
  • the preparation of the high molecular anionic emulsion flocculant polymer solution and the preparation of the cationic starch were similar to that described herein above.
  • the water-soluble flocculant polymers were Products F, G, and H, and the cationic starches were Products I and J, described herein above.
  • the order of addition of the components was starch first, followed by the high molecular weight flocculant polymer and then, as in the previous two Examples 1 and 2, after the shearing (mixing) step, adding the zirconia sol. The results are given in Table 11.
  • Example 4 was similar to Example 3, except that instead of a high molecular weight anionic emulsion flocculant polymer, polyampholytes (Products D and K) were used. The order of addition was first cationic starch (Product J) , followed by polyampholyte (Product D or K) , and then after the shearing (mixing) step, a zirconia sol. The zirconia sols were those listed in Table 1.
  • Example 5 a 100 % polyacrylic polymer solution with a molecular weight of approximately 1 million was used. This is Product M described herein above .
  • the water-soluble flocculant polymer used in this experiment was a cationic emulsion polymer, Hydraid ® 954 (Product N) , described herein above.
  • Table 14 shows that again the microparticle system of the invention comprising a zirconia sol, a cationic starch, and a cationic emulsion (flocculant) was effective. The best results occurred for ⁇ Zr 100/20" which gave the lowest turbidity, i.e.- 18 NTU (best retention) and the highest drainage, i.e. 315 ml.
  • Example 7
  • Example 7 illustrates the effectiveness of using an alumina sol as the inorganic sol of the microparticle system of the invention.
  • the alumina sol used was an alumina hydrate sol dispersed in water and manufactured by Nissa Chemical, and available under . the trademark ALUMINASOL® 100.
  • the product properties are given in Table 15.
  • This Example 8 demonstrates the effectiveness of various formulations of the instant invention comprising a zirconia sol as the inorganic sol in improving drainage, retentions, and various sheet properties, including formation, brightness, and opacity, of a synthetic, aqueous cellulosic furnish.
  • the composition of this furnish was designed to mimic a typical alkaline, wood-free furnish used to manufacture base sheet for coated and uncoated magazine or printing and writing grades .
  • the synthetic furnish used for drainage and retention tests and for making handsheets was prepared with the following components :
  • Fiber 50/50 wt % bleached hardwood kraft/bleached softwood kraft
  • Filler 50/50 wt % ground calcium carbonate
  • the dry lap pulp was soaked in tepid water for 10 minutes and then diluted to 2 wt % solids in water and refined with a laboratory scale Valley Beater to a
  • the starch, size, and fillers were subsequently added to the refined pulp in order.
  • the pH of the pulp slurry was typically 7.5 + 0.3.
  • the pulp slurry was diluted further with tap water to approximately 1.0 wt % consistency to form thin stock for testing.
  • Example 8 The drainage and retention tests for Example 8 generally followed the sequence for standard tests under the following conditions, however, only a flocculant, i.e. a high molecular weight water soluble polymer (Product N) and a zirconia sol were used.
  • a flocculant i.e. a high molecular weight water soluble polymer (Product N) and a zirconia sol were used.
  • % Drainage Improvement (Drain Time with No Treatment - Drain Time With Treatment') x 10Q Drain Time with No Treatment Retentions Test Procedure (FPR, FPAR, FPFR)
  • Hand sheets were prepared at 70 gs basis weight using a Noble & Wood Hand Sheet Mold. This apparatus generates a 20cm x 20 cm square hand sheet. The mixing time / speed sequence used in preparing hand sheets was the same as the sequence used for the drainage test procedure. The treated furnish sample is poured into the deckle box of the Noble & Wood handsheet machine and the sheet is prepared employing standard techniques well known by those skilled in the art.
  • Tests 5-16 of Table 17 show that the addition of zirconia sols with a cationic, high molecular weight polymer (Tests 5- 16) significantly improve stock drainage and retention, particularly filler retention.
  • the results of Tests 9 and 13 demonstrate the effectiveness of zirconia sols to improve stock drainage, filler retention, and sheet brightness without sacrificing sheet formation. Increasing dosages of the zirconia sol (Tests 13-15) yield even greater improvements in stock drainage, retentions, sheet brightness and opacity without any loss in sheet formation.

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Abstract

Procédé de fabrication du papier consistant à ajouter à une suspension de pâte à papier ou à une composition de fabrication de la pâte à papier, un système de microparticules servant d'agent de rétention ou d'égouttage comprenant un polymère choisi dans le groupe des polymères polyampholytes, polymères coagulants, polymères solubles dans l'eau à haut poids moléculaire, et un sol inorganique choisi dans le groupe des sols de zircone et des sols d'alumine. Eventuellement, un amidon cationique peut appartenir au système microparticulaire et peut être ajouté préalablement à l'addition du polymère. Selon une variante du procédé, l'addition du sol inorganique peut se faire après la dernière étape de cisaillement.
PCT/US2000/034488 2000-01-12 2000-12-19 Utilisation de sols inorganiques dans la fabrication du papier WO2001051707A1 (fr)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8480853B2 (en) 2010-10-29 2013-07-09 Buckman Laboratories International, Inc. Papermaking and products made thereby with ionic crosslinked polymeric microparticle
CN109293827A (zh) * 2018-09-26 2019-02-01 浙江鑫甬生物化工股份有限公司 珠状阳离子聚丙烯酰胺类助留剂的制备方法及其对纸浆浆料的助留应用

Citations (4)

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Publication number Priority date Publication date Assignee Title
US4911790A (en) * 1987-01-09 1990-03-27 Stfi Paper production
US4964954A (en) * 1987-03-03 1990-10-23 Eka Nobel Ab Process for the production of paper
US5512135A (en) * 1991-07-02 1996-04-30 Eka Nobel Ab Process for the production of paper
US5858174A (en) * 1995-07-07 1999-01-12 Eka Chemicals Ab Process for the production of paper

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4911790A (en) * 1987-01-09 1990-03-27 Stfi Paper production
US4964954A (en) * 1987-03-03 1990-10-23 Eka Nobel Ab Process for the production of paper
US5512135A (en) * 1991-07-02 1996-04-30 Eka Nobel Ab Process for the production of paper
US5858174A (en) * 1995-07-07 1999-01-12 Eka Chemicals Ab Process for the production of paper

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8480853B2 (en) 2010-10-29 2013-07-09 Buckman Laboratories International, Inc. Papermaking and products made thereby with ionic crosslinked polymeric microparticle
CN109293827A (zh) * 2018-09-26 2019-02-01 浙江鑫甬生物化工股份有限公司 珠状阳离子聚丙烯酰胺类助留剂的制备方法及其对纸浆浆料的助留应用
CN109293827B (zh) * 2018-09-26 2021-01-01 浙江鑫甬生物化工股份有限公司 珠状阳离子聚丙烯酰胺类助留剂的制备方法及其对纸浆浆料的助留应用

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