EP1173641A1 - Colloide acide dans un systeme microparticulaire utilise en papeterie - Google Patents

Colloide acide dans un systeme microparticulaire utilise en papeterie

Info

Publication number
EP1173641A1
EP1173641A1 EP99946856A EP99946856A EP1173641A1 EP 1173641 A1 EP1173641 A1 EP 1173641A1 EP 99946856 A EP99946856 A EP 99946856A EP 99946856 A EP99946856 A EP 99946856A EP 1173641 A1 EP1173641 A1 EP 1173641A1
Authority
EP
European Patent Office
Prior art keywords
furnish
melamine
formaldehyde
paper
solids
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP99946856A
Other languages
German (de)
English (en)
Other versions
EP1173641A4 (fr
Inventor
Charles R. Hunter
Craig W. Vaughan
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Calgon Corp
Original Assignee
Calgon Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Calgon Corp filed Critical Calgon Corp
Publication of EP1173641A4 publication Critical patent/EP1173641A4/fr
Publication of EP1173641A1 publication Critical patent/EP1173641A1/fr
Withdrawn legal-status Critical Current

Links

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
    • D21H17/33—Synthetic macromolecular compounds
    • D21H17/46—Synthetic macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
    • D21H17/47—Condensation polymers of aldehydes or ketones
    • D21H17/49—Condensation polymers of aldehydes or ketones with compounds containing hydrogen bound to nitrogen
    • 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
    • D21H17/46—Synthetic macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
    • D21H17/47—Condensation polymers of aldehydes or ketones
    • D21H17/49—Condensation polymers of aldehydes or ketones with compounds containing hydrogen bound to nitrogen
    • D21H17/51—Triazines, e.g. melamine
    • 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
    • D21H17/46—Synthetic macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
    • D21H17/54—Synthetic macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds obtained by reactions forming in the main chain of the macromolecule a linkage containing nitrogen
    • D21H17/55—Polyamides; Polyaminoamides; Polyester-amides
    • 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
    • D21H17/46—Synthetic macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
    • D21H17/54—Synthetic macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds obtained by reactions forming in the main chain of the macromolecule a linkage containing nitrogen
    • D21H17/56—Polyamines; Polyimines; Polyester-imides
    • 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
    • D21H17/68—Water-insoluble compounds, e.g. fillers, pigments siliceous, e.g. clays
    • 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
    • D21H23/02—Processes or apparatus for adding material to the pulp or to the paper characterised by the manner in which substances are added
    • D21H23/04—Addition to the pulp; After-treatment of added substances in the pulp
    • 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
    • D21H23/02—Processes or apparatus for adding material to the pulp or to the paper characterised by the manner in which substances are added
    • D21H23/04—Addition to the pulp; After-treatment of added substances in the pulp
    • D21H23/06—Controlling the addition
    • D21H23/14—Controlling the addition by selecting point of addition or time of contact between components

Definitions

  • the present invention relates to an improved microparticle system for use as an aid in making a paper product, i.e. paper or paperboard, with improved properties in the areas of retention, drainage, and sheet formation. More particularly, it pertains to a microparticle system comprising an acid colloid as a microparticle or an inorganic particulate material of the microparticle system.
  • a dilute aqueous composition known as "furnish” or “stock” is sprayed onto a moving mesh known as a "wire” .
  • Solid components of this composition such as cellulosic fibers and inorganic particulate filler material, 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, retention and formation (D/R/F) aids are used in the papermaking process .
  • 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. Because both the cellulosic fibers and many common filler materials are negatively charged, they are mutually repellent. Generally, the only factor tending to enhance retention is mechanical entrainment. Therefore, a retention aid is generally used to improve retention of the fibers and fillers on the wire. The retention of fines and fillers is important to the papermaker to insure the capture of colloidally sized particles in the sheet. First pass retention (FPR) measures this ability of a retention program. Colloidal silica has been used in the past as a microparticle in a retention aid for alkaline fine paper. Silica has to be used properly in order to enhance the retention of fines and fillers by forming microflocs that capture colloidal material and allow the pulp slurry to dewater quickly.
  • FPR First pass retention
  • Drainage relates to the rate of removal of water from the stock or furnish as the paper sheet is formed. Drainage usually refers to water removal that takes place before any pressing of the paper sheet subsequent to formation of the sheet. Thus, drainage aids are used to improve the overall efficiency of dewatering in the production of paper or paperboard.
  • Formation relates to the formation of the paper or paperboard sheet produced in the papermaking process. Formation is generally evaluated by the variance of light transmission within a paper sheet. A high variance is indicative of "poor" formation and a low variance is generally indicative of "good” formation. Generally, as the retention level increases, the level of formation generally decreases from good formation to poor formation.
  • Retention and drainage aids are additives that are used to flocculate the fine solid material present in the stock or furnish to improve these parameters in the papermaking process .
  • the use of such additives is limited by the effect of flocculation on the paper sheet formation.
  • Retention and drainage aids are generally added to the furnish in the wet-end of the paper machine, and generally are of three types, viz:
  • a microparticle systems which may include flocculant and/or a coagulant.
  • a microparticle system generally gives the best result as a retention and drainage aid, and has been widely described in the prior art.
  • bentonite clay and colloidal silica have been used to improve drainage, retention, and formation.
  • Examples of publications describing 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 disclosed for use in conjunction with one of various inorganic materials such as silica, bentonite, china clay, and organic materials; WO-A-97/16598 wherein kaolin is disclosed for use in conjunction with one of various cationic polymers; and EPO 805234 wherein bentonite, silica, or acrylate polymer is disclosed for use in conjunction with a cationic dispersion polymer.
  • U.S. Patent Nos . 4,305,781 and 4,753,710 disclose the use of high molecular weight nonionic and ionic polymers in conjunction with bentonite clay to aid in dewatering and retention in papermaking.
  • U.S. Patent Nos. 4,388,150 and 4,385,961 teach the use of cationic starch and colloidal silica.
  • U.S. Patent Nos. 4,643,801 and 4,750,974 describe the use of cationic starch, anionic high molecular weight polymer, and colloidal silica in papermaking.
  • U.S. Patent No. 5,185,062 describes anionic polymer acting as a microparticle with a high molecular weight cationic flocculant.
  • U.S. Patent No. 5,167,766 teaches the use of charged organic polymeric microbeads as a microparticle in papermaking.
  • a microparticle system generally comprises a polymer flocculant with or without a cationic coagulant and a fine particulate material.
  • the fine particulate material improves the efficiency of the flocculant and/or allows smaller, more uniform floes to be produced.
  • melamine-formaldehyde (MF) acid colloids for wet strength in paper is well known.
  • Reference is made to TAPPI Monograph No. 29 "Wet Strength in Paper and Paperboard", C.S. Maxwell, J.P. Weidner, ed.. US. Patent No. 2,345,543 describes the preparation of stable melamine-formaldehyde acid colloids.
  • U.S. Patent No. 2,485,080 includes the incorporation of urea into the condensation products.
  • U.S Patent Nos. 2,559,220 and 2,986,489 teach the use of these colloids to increase the wet strength of paper.
  • U.S. Patent No. 5,286,347 describes the use of melamine formaldehyde colloid for pitch control in papermaking.
  • U.S. Patent No. 4,461,858 describes the use of polyvinyl alcohol - melamine formaldehyde colloid blends for wet- strength in paper.
  • U.S. Patent No. 4,009,706 teaches the use of melamine formaldehyde colloid and anionic high molecular weight polymer to flocculate raw sugar.
  • the present invention has met this above described need.
  • the present invention relates to a microparticle system used as a retention and drainage aid in a papermaking process .
  • a method of producing paper which comprises adding to a paper furnish a microparticle system as a retention and/or drainage aid which comprises a high molecular weight polymer flocculant and an inorganic particulate material comprising acid colloid comprised of an aqueous solution of a water soluble polymer or copolymer.
  • a microparticle system which is added to a paper furnish as a retention and/or drainage aid, and which microparticle system comprises a high molecular weight polymer flocculant and an inorganic particulate material comprising an acid colloid comprised of an aqueous solution of a water-soluble polymer or copolymer.
  • a paper or a paperboard product with improved properties in the area of retention, drainage and formation wherein the paper or paperboard product is made by adding a microparticle system to an aqueous cellulosic paper furnish, wherein the microparticle system comprises a high molecular weight polymer flocculant and an inorganic particulate material comprising an acid colloid comprised of an aqueous solution of a water-soluble polymer or copolymer.
  • a fourth aspect of the invention involves a process in which paper or paperboard is made by forming an aqueous cellulosic paper furnish, the steps comprising:
  • the acid colloid is comprised of an aqueous solution of a water-soluble polymer selected from the group consisting of melamine aldehyde, urea aldehyde, and melamine-urea aldehyde and the aldehyde is
  • R ⁇ — C — H wherein Rl is selected from the group consisting of straight and branched C x . 4 alkyl .
  • the acid colloid is present in the stock or furnish in an amount ranging from about 0.0005% to about 0.5% by weight based on the dry weight of the solids in the stock or furnish.
  • the aldehyde is formaldehyde and the acid colloid is melamine formaldehyde, which may be etherfied with a linear or branched alcohol.
  • the high molecular weight (HMW) polymer flocculant is present in an amount ranging from about 0.0025% to about 1.0% by weight based on the dry weight of the solids in the furnish.
  • a high charge density cationic coagulant may be added to the stock or furnish prior to a first shearing stage or may in some instances be added prior to or after the addition of the acid colloid.
  • the acid colloid and/or the flocculant could be added to the stock or furnish prior to the HMW flocculant and/or the coagulant and/or prior to the first shearing stage.
  • the single figure illustrates a portion of a typical paper machine and the points of addition of the components of the microparticle system of the present invention in a preferred form.
  • the invention is directed to a microparticle system used as a retention/drainage/formation (R/D/F) aid for particular use in the wet end of a paper machine in the papermaking process for both acid and alkaline fine paper.
  • R/D/F retention/drainage/formation
  • the term "paper” includes products comprising a cellulosic sheet material including paper sheet, paper board, and the like.
  • the "microparticle system” of the invention refers to the combination of at least one hydrophilic polymer used as a flocculant and at least one inorganic particulate material which is a microparticle in the system, and possibly, a coagulant.
  • the microparticle or inorganic particulate material is an acid colloid.
  • the components of this combination may be added together to the stock or furnish to be treated, but are preferably added separately in the manner and order described herein below.
  • the invention can be carried out using a conventional papermaking machine.
  • 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 or chest by blending pigment or filler material, the appropriate fiber, any desired strengthening agent and/or other additives, and water which may be recycled water.
  • the thin stock may be cleaned in a conventional manner, e.g., using a vortex cleaner.
  • the thin stock is cleaned by passage through a centriscreen.
  • the thin stock is usually pumped along the paper machine by one or more centrifugal pumps known as fan pumps. For instance, the thin stock may be pumped to the centriscreen by a first fan pump.
  • the thick stock can be diluted by water to form the thin stock prior to 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 thin stock may be cleaned further by passage through a second centriscreen or pressure screen and passed through a headbox prior to the sheet forming process of a paper machine.
  • the sheet forming process may be carried out by use of any conventional paper or paperboard forming machine, for example a flat wire fourdrinier, a twin wire former, or a vat former, or any combination of these forming machines .
  • An approach system to a paper machine may comprise the components shown in the single figure. These components include a fan pump 1, a pressure screen 2, and a headbox 3.
  • the thick stock may be diluted by water to form a thin stock prior to the stock's entry into fan pump 1 by passing the thick stock and dilution water through a mixing pump (not shown) .
  • the thin stock is cleaned of contaminants by passage through pressure screen 2 and the thin stock that leaves pressure screen 2 is passed to headbox 3 prior to forming the sheet .
  • the single figure also illustrates the preferred points of addition for the components of the microparticle system of the present invention.
  • the coagulant is added to the thin stock prior to the thin stock being passed through fan pump 1 which travel is indicated by arrow 4 and which addition is indicated by arrow 5.
  • the flocculant is added to the thin stock as it exits fan pump 1, as indicated by arrow 6, and the microparticle particulate material comprising acid colloid is added to the thin stock as the thin stock exits pressure screen 2 as indicated by arrow 7.
  • Fan pump 1 and pressure screen 2 produce high shear stages in the paper machine .
  • the high molecular weight (HMW) flocculant polymer of the microparticle system is preferably added before the thin stock reaches the last point of high shear and the resultant thin stock is preferably sheared, e.g., at the last point of high shear, and preferably before adding the acid colloid material of the microparticle system of the invention.
  • the flocculant is shown as being added before the thin stock travels through pressure screen 2 and the acid colloid is shown as being added after the stock passes through pressure screen 2.
  • the HMW polymer flocculant of the microparticle system of the invention is added to the thin stock (i.e. having a solids content of desirably not more than 2% or, at the most, 3% by weight) rather than to the thick stock.
  • the HMW flocculant 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 high molecular weight flocculant polymer generally comprises an agent for aggregating the solids, especially the fines, in the papermaking furnish.
  • fines means fine solid particles and fibers as defined in TAPPI Test Methods T261 and T269, respectively.
  • Flocculation of the fines in the stock or furnish may be brought about by the high molecular weight polymer itself or in combination with a medium molecular flocculant or a coagulant which may be a high charge density cationic coagulant. 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 high molecular weight polymer flocculant is a polymer providing flocculant action, preferably, by itself.
  • high molecular weight polymer flocculants suitable for use herein are those having a weight average molecular weight of about 100,000 or more, especially 500,000 or more.
  • the weight average molecular weight is about above 1 million and often above about 5 million, and typically, in the range 10 to 30 million or more.
  • These polymers may be linear, branched, cationic, anionic, nonionic, amphoteric, or hydrophobically modified polymers of acrylamide or other nonionic monomers.
  • the amount of high molecular weight polymer flocculant of the microparticle system added to the paper furnish in the present invention may be any amount sufficient to give a substantial effect in flocculating the solids, especially the fines, which are present in the paper furnish.
  • the total amount of water soluble flocculant polymer added may be in the range of about 0.0025% to about 1.0 %, more preferably, in the range 0.01 % to 0.2 %, and most preferably, in the range of about 0.0125 % to about 0.1% by weight (dry weight of polymer based on the dry weight of the solids present in the furnish) .
  • the addition may be carried out in one or more doses at one or more addition sites and, preferably, is carried out in one dose to the thin stock flow after the fan pump, which causes a high shear action.
  • the floes formed by the high molecular weight polymer flocculant are subjected to a shearing action before addition of the acid colloid of the microparticle system of the invention.
  • this shearing action is induced by a pressure screen which causes a high shear action.
  • the acid colloid is comprised of an aqueous solution of a water soluble polymer or copolymer.
  • any melamine aldehyde type polymer or copolymer can be used.
  • the polymer is prepared by using a) melamine or a substituted melamine; and b) an aldehyde having the formula :
  • R x — C — H wherein Rl is selected from the group consisting of straight and branched C 1-4 alkyl .
  • the preferred aldehydes are methanal (formaldehyde), ethanal, propanal, gloyoxal and glutaraldehyde, the most preferred aldehyde being formaldehyde .
  • the mole ratio of component a) to component b) above should range from about 1:1 to about 1:10, with the preferred ratio being about 1:3 to 1:6.
  • the most preferred mole ratio is about 1 mole of melamine or derivative thereof to about 3 moles of an aldehyde.
  • the most preferred polymer is prepared from melamine and formaldehyde, and the mole ratio of melamine to formaldehyde is about 1:3.
  • the melamine aldehyde type polymers of the present invention are insoluble in water, but can be maintained in a colloidal suspension in acidic solutions. Any acid or compatible combination of acids can be used to prepare the melamine aldehyde acid colloids, although hydrochloric acid is preferred.
  • the active content of the melamine aldehyde-type polymer in acidic suspension or solution should range from about 0.1% to about 20%, preferably 1% to about 15%, and most preferably, about 4% to about 12%.
  • the pH should be sufficiently low, i.e., between 1.0 to 2.5 with an aqueous mineral or organic acid, in order to keep the melamine aldehyde type polymer in fine colloidal suspension.
  • Urea aldehyde type polymer solutions suitable for use in the present invention are those wherein the aldehyde is defined as above, most preferably urea- formaldehyde solutions.
  • the mole ratio of urea to aldehyde should range from 1:1 to 1:10, with the most preferred ratio being 1:3 to 1:6.
  • Melamine urea aldehyde copolymer solutions may also be employed in the present invention. These solutions are prepared from an aldehyde component as described above, urea, and melamine or a substituted melamine. Preferred are melamine-urea-formaldehyde copolymer solutions.
  • the melamine-urea-aldehyde copolymer solutions suitable for use in the present invention contain 1 to 70 mole percent urea, 30 to 99 mole percent melamine, and about 1 to 4 moles of aldehyde for each mole of combined melamine and urea in the acidic aqueous medium.
  • the copolymer solution for use in the present invention ranges from 0.1 to 20 percent solids, and preferably 1 to 12 percent solids.
  • the acid colloid of the invention may be a copolymer comprising melamine aldehyde and condensates which include ammeline-aldehyde, dicyandiamidealdehyde, biguanidine-aldehyde, ureaformaldehyde polyalkylene polyamine, and polyureido.
  • the acid colloid is prepared by reaction of the specified aldehydes with the amine and aging the solution under acid conditions, typically using hydrochloric acid. As aging proceeds, the colloidal particles grow to a size of 20 to 200 Angstroms.
  • the average degree of polymerization is 10 to 20 methylolated melamine units.
  • the particle carries a cationic charge, i.e. some of the secondary amine units are protonated.
  • the colloidal solutions characteristically exhibit a blue haze.
  • the solutions are stored at a concentration of 8-12% active polymer.
  • the solutions may be composed exclusively of amine and aldehyde, or may be derivatives thereof.
  • the solutions may be partially etherified with an alcohol, glycol, or other hydroxyl containing species.
  • the solutions may be a co-condensate of melamine - formaldehyde and another aminoplast, which can then be etherified.
  • the solutions may be a mixture of such aminoplasts, which are then used to form the acid colloid.
  • the aminoplasts that form the colloid may also be copolymers of ethylenically unsaturated monomers such as acrylamide, dimethylaminoethyl acrylate, diallyldimethyl ammonium chloride, or methacrylamidopropyl trimethylammonium chloride.
  • these acid colloids are now being applied as part of a microparticle drainage, retention, and formation program with respect to making paper or paperboard.
  • the acid colloid may be that disclosed in the aforesaid U.S. Patent No. 5,382,368 which is incorporated herein by reference.
  • the amount of acid colloid added to the paper furnish ranges between about 0.0005% to about 0.5%, and preferably, between about 0.005% to about 0.25% by dry weight based on the dry weight of the solids present in the paper stock or furnish. This addition may be carried out in one or more dosages at one or more feed points or addition sites, but preferably, in one dose, and preferably, after the pressure screen 2 in the figure and at least between pressure screen 2 and headbox 3.
  • the acid colloid of the microparticle system of the invention preferably is melamine-formaldehyde acid colloid.
  • HMW flocculant polymer generally will cause the formation of large floes of the suspended solids in the paper furnish to which the polymer is added. These large floes are immediately or subsequently broken down by high shear to very small floes that are known in the art as “microflocs” . This "high shear” may be induced by passing the flocced paper furnish through the pressure screen 2 of the figure.
  • a water soluble polymer generally lower in molecular weight than the flocculant, may be employed as a coagulant by its addition to the thick stock, and preferably is added to the furnish prior to the furnish passing through fan pump 1. This coagulant may be a high charge density cationic polymer.
  • the coagulant polymer is a nitrogen containing cationic polymer
  • it may have a charge density of about 0.2, preferably, at least 0.35 and, most preferably, 0.4 to 2.5 or more, equivalents of nitrogen per kilogram of polymer.
  • the amount of cationic monomer will normally be about 2 mole % and usually about 5 mole %, and, preferably, at least about 10 mole %, based on the total amount of monomers used for forming the polymer.
  • Both natural and synthetic inorganic and organic coagulants can be used in the microparticle system of the invention.
  • suitable cationic coagulants include: polydiallyldimethyl ammonium chloride (p-DADMAC) ; polyalkylamines; cationic polymers of epichlorohydrin with dimethylamine and/or ammonia or other primary and secondary amines; polyamidoamines ; copolymers of a non- ionic monomer, such as acrylamide, with a cationic monomer, such as DADMAC or acryloyloxyethyltrimethyl ammonium chloride; cyanoguanidine modified polymers of urea/formaldehyde resins; melamine/formaldehyde polymers; urea/formaldehyde polymers; polyethylene imines; cationic starches; monomeric and polymers of cationic aluminium salts; amphoteric polymers processing a net cationic charge; and blends of the aformentioned coagulants.
  • p-DADMAC polydiallyldimethyl ammonium chlor
  • the amount of coagulant of the microparticle system of the invention added to stock or furnish may be any amount sufficient to give a substantial effect in coagulating the solids present in the paper furnish.
  • the total amount of water soluble coagulant polymer may be in the range of about 0.0025 to 1.0 %, and more preferably, in the range of about 0.005 % to about 0.50 % by weight (dry weight of polymer based on the dry weight of the solids present in the paper furnish) . If a medium molecular weight (MMW) flocculant is used instead of the cationic coagulant, this flocculant may be added prior to the stock passing through fan pump 1.
  • MMW medium molecular weight
  • MMW flocculant suitable for use in the invention are those having a weight average molecular weight ranging from 500,000 to about between 5 and 6 million.
  • This chemical additive may be a copolymer of an acrylamide or any unsaturated monomer.
  • a suitable MMW flocculant may include the ECCatTM 500 copolymers available from Calgon Corporation, PA.
  • the amount of MMW flocculant may be any amount sufficient to give a substantial effect in coagulating the solids present in the paper or furnish.
  • the total amount of MMW flocculant may be in the range of about 0.0025 to 1.0 wt . % based on the dry weight of the solids present in the furnish.
  • the dosages would range from 0.01 to 5.0 lb. /ton polymer.
  • the coagulant or MMW flocculant may be added to the thick stock prior to the fan pump 1
  • the HMW flocculant polymer may be added to the thin stock after the stock's passage through fan pump 1
  • the acid colloid of the invention may be added to the thin stock after the stock's passage through pressure screen 2.
  • these chemical additives may be added to the stock in a different sequence and/or at different feed points than that shown in the figure.
  • the initial thick stock can be made from any conventional papermaking furnish, such as, traditional chemical pulps, for instance bleached and unbleached sulphate or sulphite pulp; mechanical pulps such as groundwood; thermomechanical pulp; or chemi- thermochemical pulp; or recycled pulp, such as deinked waste, fiber filler composites from aggregating or recycling processes; and any mixtures thereof.
  • traditional chemical pulps for instance bleached and unbleached sulphate or sulphite pulp
  • mechanical pulps such as groundwood; thermomechanical pulp; or chemi- thermochemical pulp
  • recycled pulp such as deinked waste, fiber filler composites from aggregating or recycling processes; and any mixtures thereof.
  • the stock or furnish employed in the invention, and in the final paper can be substantially unfilled (e.g., containing less than 10% and generally less than 5% by weight filler in the final paper) , or filled with a filler which can be provided in an amount of up to 50% by weight based on the dry weight of the solids of the stock or up to 40% by weight based on the dry weight of the paper.
  • a filler which can be provided in an amount of up to 50% by weight based on the dry weight of the solids of the stock or up to 40% by weight based on the dry weight of the paper.
  • any conventional white pigment filler such as calcium carbonate, kaolin clay, calcined kaolin, titanium dioxide, or talc, or a combination thereof may be present.
  • the filler (if present) is, preferably, incorporated into the furnish in a conventional manner, and before addition of the components of the microparticle system of the invention.
  • the stock or furnish employed in the invention may include other known optional additives, such as, rosin, alum, neutral sizes or optical brightening agents. It may include a strengthening or binding agent, and this can, for example, comprise a starch, such as cationic starch.
  • the pH of the stock is generally in the range of from about 4 to about 9.
  • the thin stock has a solids content of 0.1% to 3% by weight, or a fiber content of 0.1% to 2% by weight.
  • the thin stock will usually have a solids content of from 0.1% to 2% by weight. These percentages are based on the dry weight of the solids in the stock.
  • the acid colloid employed as the microparticle particulate material in the microparticle system of the invention is preferably melamine-formaldehyde acid colloid or derivatives thereof.
  • the acid colloid is comprised of an aqueous solution of a water- soluble polymer or copolymer, which is preferably a melamine aldehyde, preferably melamine formaldehyde.
  • a water- soluble polymer or copolymer which is preferably a melamine aldehyde, preferably melamine formaldehyde.
  • These particles are readily dispersed in the aqueous pulp suspension in a papermaking process to enhance the surface characteristics of the final paper product. These particles, in general, will have an average particle size of about 10 to about 20 nm.
  • an acid colloid i.e. melamine formaldehyde
  • a flocculant and a coagulant can increase drainage and retention, and improve sheet formation in a papermaking process.
  • MF Melamine-formaldehyde
  • Colloidal Silica - a 15% active solution available from Nalco (Naperville, IL) .
  • Carbital 60 - a dry, ground calcium carbonate available from ECC International, Inc. (Atlanta, GA) .
  • a synthetic alkaline paper furnish was prepared and used in drainage and retention tests and in making handsheets. The following components were used:
  • Fiber 50 / 50 wt % bleached hardwood
  • Kraft / bleached softwood Kraft Filler 50 / 50 wt % ground calcium carbonate (Carbital 60) / precipitated calcium carbonate. Filler loading: 20 wt % based on fiber solids
  • a dry lap pulp was soaked in tepid water for 10 minutes, diluted in water to a consistency of 2 wt % solids, and refined or beaten with a Laboratory Scale Voith Allis Valley Beater to a Canadian Standard Freeness (CSF) of 590 ml.
  • the starch, size, and fillers were added in this sequence to the refined pulp slurry.
  • 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.
  • the furnish is representative of a typical alkaline fine paper furnish used to make printing and writing grades of paper, and was used in Examples 1 through 23. Drainage Test Procedure
  • the contents in the mixing jar were transferred to a 500 ml graduated drainage tube fitted on the bottom with a 100 mesh screen.
  • the tube was inverted 5 times to ensure that the stock was homogenous.
  • the bottom stopper of the tube was removed and the elution times for 100, 200, and 300 ml elution volumes were measured.
  • the elution time at a volume of 300 ml for an untreated stock blank should preferably be greater than 60 seconds.
  • the mixing time / speed (seconds/rpm) sequence was similar to that used in the drainage test procedure above in order to simulate chemical addition points with the following change : at t 30 , the bottom stop cock was opened and the first 100 ml of eluate were collected.
  • Handsheets were prepared at 70 grams per square meter basis weight using a Noble & Wood Hand Sheet Mold. This apparatus generates a 20cm x 20cm square handsheet .
  • the mixing time / speed (seconds/rpm) sequence used in preparing hand sheets was the same as the sequence used for the drainage test procedure.
  • the treated furnish sample was poured into the deckle box of the Noble & Wood handsheet machine and the sheet was prepared employing standard techniques well known by those skilled in the art .
  • Sheet formation was measured on handsheets using an MK Systems Formation Tester, Model M/K950R.
  • Examples 1-8 Drainage
  • Table 1 show drainage improvement results realized when using 10 and 20lbs./ton of cationic starch with an anionic HMW flocculant and melamine- formaldehyde (MF) as the acid colloid in the microparticle system of the invention.
  • the cationic starch was fed pre-fan pump, the anionic flocculant was fed pre-screen, and MF was fed post-screen as described herein above for the mixing time and speed sequence in the drainage test procedure.
  • Table 1 shows an important discovery in the use of MF as a microparticle in the papermaking process.
  • colloidal silica (a prior art microparticle) requires more than lOlb/ton of cationic coagulant or starch in order to be an effective drainage aid in the production of paper.
  • the results of Table 1 seem to indicate that the use of an acid colloid, such as melamine formaldehyde, in conjunction with an anionic flocculant can decrease the amount of cationic starch or coagulant needed in a paper mill to attain desirable drainage levels in the paper machine during the paper making process .
  • Examples 9 - 14 show comparative data between the colloidal silica presently being as a microparticle particulate material and melamine formaldehyde (MF) as the microparticle particulate material of the invention.
  • Examples 9-14 First Pass Retention (FPR)
  • FPR First Pass Retention
  • Table 2 Examples 9-14 demonstrate an enhanced performance from MF compared to silica at the dosages shown with respect to first pass retention when using 10 lb. /ton of cationic starch and 0.5 lb. /ton of an active anionic flocculant. Retention was measured using the Britt method (TAPPI Test Method T269) according to the mixing sequence discussed herein above in the drainage test procedure. Table 2
  • Examples 15-20 First Pass Ash Retention (FPAR)
  • FPAR First Pass Ash Retention
  • Table 3 illustrates an enhanced performance from MR (present invention) compared to colloidal silica (prior art) at the dosages shown when using 10 lb. /ton of cationic starch and 0.5 lb. /ton of an active anionic flocculant.
  • Examples 21-23 Formation Table 4 illustrates the advantage of using melamine formaldehyde (MF) as a microparticle particulate material versus using colloidal silica in sheet formation. (The higher the Formation Index, the better the sheet formation.) Generally, high levels of drainage are associated with large decreases in Formation Index. As seen from Examples 22 and 23, at equivalent drainage levels, melamine formaldehyde produced better sheet formation than the colloidal silica of the prior art.
  • MF melamine formaldehyde

Landscapes

  • Paper (AREA)
  • Separation Of Suspended Particles By Flocculating Agents (AREA)

Abstract

Ce système microparticulaire, utilisé comme agent contribuant à la retenue et à l'égouttage lors de la production de produits papier alcalins et acides, renferme un polymère floculant de poids moléculaire élevé (6) ainsi qu'un colloïde acide (7) et un coagulant cationique ou un floculant de poids moléculaire moyen (5). La teneur en colloïde acide (7), lequel est constitué d'une solution aqueuse d'un polymère hydrosoluble ou d'un copolymère de mélamine-aldéhyde, de préférence, d'aldéhyde formique de mélamine, est comprise entre 0,0005 et 0,5 %, en pourcentage pondéral, du poids sec des matières solides constituant la composition de fabrication. On peut ajouter ce polymère floculant de poids moléculaire élevé (6) à la composition de fabrication en aval de la pompe de soufflante (1) et en amont de l'épurateur sous pression (2). On peut ajouter le colloïde acide (7) à la composition de fabrication en aval de l'épurateur sous pression (2) et le coagulant/floculant de poids moléculaire moyen (5) en amont de la pompe de soufflante (1). Il est également possible de modifier cette suite d'ajouts de substances chimiques et d'ajouter, par exemple, l'acide colloïde (7) en amont ou en aval de la pompe de soufflante (1) ou en amont de l'épurateur sous pression (2). L'adjonction de ce système microparticulaire à la composition de fabrication a l'avantage d'améliorer la retenue et l'égouttage ainsi que de faciliter la formation des feuilles lors du processus de fabrication du papier.
EP99946856A 1998-09-22 1999-09-08 Colloide acide dans un systeme microparticulaire utilise en papeterie Withdrawn EP1173641A1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
US10137798P 1998-09-22 1998-09-22
US101377P 1998-09-22
PCT/US1999/020766 WO2000017451A1 (fr) 1998-09-22 1999-09-08 Colloide acide dans un systeme microparticulaire utilise en papeterie

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EP1173641A1 true EP1173641A1 (fr) 2002-01-23

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KR (1) KR20010075219A (fr)
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AU (1) AU761303B2 (fr)
BR (1) BR9913992A (fr)
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MXPA04003942A (es) * 2003-05-05 2007-06-29 German Vergara Lopez Un sistema de retencion y drenaje recomendado para la fabricacion de papel, cartulina, carton y otros productos similares.
US20070133346A1 (en) * 2005-12-14 2007-06-14 Tommy Jacobson Mixing of chemicals into a thin stock pipe
GB0702248D0 (en) 2007-02-05 2007-03-14 Ciba Sc Holding Ag Manufacture of Filled Paper
GB0702249D0 (en) 2007-02-05 2007-03-14 Ciba Sc Holding Ag Manufacture of paper or paperboard
CN103911902B (zh) * 2013-01-09 2017-11-03 荒川化学工业株式会社 卫生纸添加剂、使用该添加剂的卫生纸制造方法及卫生纸
CN103850150A (zh) * 2014-03-27 2014-06-11 潍坊恒联美林生活用纸有限公司 一种工业无尘擦试纸制造工艺
CN116334946A (zh) * 2022-09-22 2023-06-27 苏州赛维科环保技术服务有限公司 一种改善的废纸抄造系统及其抄造方法

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US2485080A (en) * 1944-01-04 1949-10-18 American Cyanamid Co Colloidal melamine-urea-formaldehyde copolymer solutions
US4385961A (en) * 1981-02-26 1983-05-31 Eka Aktiebolag Papermaking
US4795531A (en) * 1987-09-22 1989-01-03 Nalco Chemical Company Method for dewatering paper
US5382378A (en) * 1993-02-10 1995-01-17 Calgon Corporation Composition useful for treating suspended solids and color bodies in water systems
GB9410920D0 (en) * 1994-06-01 1994-07-20 Allied Colloids Ltd Manufacture of paper

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JP2002526681A (ja) 2002-08-20
AU761303B2 (en) 2003-06-05
WO2000017451A1 (fr) 2000-03-30
EP1173641A4 (fr) 2002-01-23
CN1318121A (zh) 2001-10-17
NZ510318A (en) 2003-07-25
ID29633A (id) 2001-09-06
KR20010075219A (ko) 2001-08-09
AU5917399A (en) 2000-04-10
NO20011442L (no) 2001-05-22
NO20011442D0 (no) 2001-03-21

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