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WO2018063273A1 - Système de drainage et processus de fabrication de produit en papier ou similaire - Google Patents

Système de drainage et processus de fabrication de produit en papier ou similaire Download PDF

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Publication number
WO2018063273A1
WO2018063273A1 PCT/US2016/054630 US2016054630W WO2018063273A1 WO 2018063273 A1 WO2018063273 A1 WO 2018063273A1 US 2016054630 W US2016054630 W US 2016054630W WO 2018063273 A1 WO2018063273 A1 WO 2018063273A1
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WIPO (PCT)
Prior art keywords
polyacrylamide
water
structurally modified
drainage system
soluble
Prior art date
Application number
PCT/US2016/054630
Other languages
English (en)
Inventor
Yuping Luo
Junhua Chen
Zheng DANG
Original Assignee
Kemira Oyj
Kemira Chemicals Inc.
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Filing date
Publication date
Application filed by Kemira Oyj, Kemira Chemicals Inc. filed Critical Kemira Oyj
Priority to PCT/US2016/054630 priority Critical patent/WO2018063273A1/fr
Publication of WO2018063273A1 publication Critical patent/WO2018063273A1/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
    • 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
    • D21H17/37—Polymers of unsaturated acids or derivatives thereof, e.g. polyacrylates
    • D21H17/375—Poly(meth)acrylamide
    • 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
    • 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

Definitions

  • the present invention relates to a process for manufacturing paper product or the like according to the preambles of the independent claims presented below, in which process a drainage system is incorporated into a fibre suspension.
  • the systems of drainage and retention aids comprising cationic high molecular weight retention polymers (polymer molecular weight range in 10- 15 million Dalton) and silica based microparticles are one of the most commonly used drainage systems on paper machines. These drainage systems are introduced into the fibre suspension in order to facilitate drainage and increase adsorption of fine particles onto the cellulose fibres so that they are retained with the fibres.
  • the efficiency of the conventional drainage and retention aids usually is deteriorated in the presence of the detrimental substances or high conductivities.
  • the loss of polymer performance leads to decreases in drainage efficiency, retention of fibre and fibre fines, and press dewatering, which increases the drying demand of the paper, requiring an increase in steam consumption in the dryer section. Steam availability is limited in the paper production facility. Consequently, drying demand of the paperboard is often a rate limiting step with respect to productivity rates.
  • the conventional high molecular weight retention polymers cannot be used in increasing dosages because they have the adverse effect of over flocculating the sheet due to the extremely high molecular weight and resulting in uneven formation of final paper.
  • One object of the present invention is to provide a process for making a paper product or the like with improved drainage, and optionally improved retention. More detailed, the object of the present invention is to provide a use of a structurally modified, water-soluble glyoxylated polyacrylamide in a papermaking process with inorganic siliceous microparticles for improving drainage, and optionally retention.
  • Another object of the present invention is to provide a process for manufacturing a paper product or the like with improved drainage, and optionally retention, when using fibre suspension comprising recycled fibre material.
  • a process, a drainage system, a use or a paper product, to which the present disclosure is related, may comprise at least one of the embodiments of the present disclosure described in this specification.
  • the embodiments and advantages mentioned in this text relate, where applicable, both to the process, the drainage system as well as to the uses according to the invention, even though it is not always specifically mentioned.
  • Typical process according to the invention for manufacturing paper product or the like comprises
  • a drainage system into the fibre suspension, which drainage system comprises inorganic siliceous microparticles and a structurally modified, water-soluble glyoxylated polyacrylamide having an intrinsic viscosity at least 0.5 dl/g, preferably at least 0.7 dl/g and more preferably at least 1 .0 dl/g, as determined by gel permeation chromatography (GPC), and
  • Typical drainage system according to the invention for improving drainage in manufacturing of paper product or the like comprises inorganic siliceous microparticles and a structurally modified, water-soluble glyoxylated polyacrylamide having an intrinsic viscosity at least 0.5 dl/g, preferably at least 0.7 dl/g and more preferably at least 1 .0 dl/g, as determined by gel permeation chromatography (GPC).
  • GPC gel permeation chromatography
  • Typical paper product comprises the drainage system according to invention, or it is manufactured by the process according to the invention.
  • the structurally modified, water-soluble glyoxylated polyacrylamide is a structurally modified, water-soluble glyoxylated cationic polyacrylamide.
  • the structurally modified, water-soluble glyoxylated polyacrylamide according to the invention when used in combination with inorganic siliceous microparticles, provide drainage improvements beyond the standard additive program of high molecular weight retention polymer and silica sol, even if the standard additive program is boosted with a conventional GPAM polymer.
  • the structurally modified, water-soluble glyoxylated polyacrylamide is a glyoxylated cationic polyacrylamide according to the invention
  • the combination with inorganic siliceous microparticles provides exceptional drainage improvements.
  • the structurally modified, water-soluble glyoxylated polyacrylamide according to the invention is preferably an aqueous composition obtainable by
  • the structurally modified, water-soluble glyoxylated polyacrylamide according to the invention is preferably made from dry polyacrylamide backbones by the method disclosed above, when it may achieve higher molecular weight than the conventional GPAM polymers, typically manufactured by glyoxylating low molecular weight cationic polyacrylamide based polymers obtained by solution polymerization.
  • the structurally modified, water-soluble glyoxylated polyacrylamide according to the invention has been found to yield stronger synergistic interaction with inorganic siliceous microparticles used as drainage aids, compared to the conventional GPAMs. Especially, a pronounced synergistic interaction has been found with inorganic siliceous microparticles having high specific surface area (SSA) and high structure in terms of low S-value, such as silica sols.
  • SSA specific surface area
  • a structurally modified, water-soluble glyoxylated polyacrylamide according to the invention has an intrinsic viscosity (IV) at least 0.5 dl/g, preferably at least 0.7 dl/g and more preferably at least 1 .0 dl/g, as determined by gel permeation chromatography (GPC); said structurally modified, water- soluble glyoxylated polyacrylamide has preferably been obtained by the method described in this application.
  • the GPC system and measurement conditions are described more specifically in Example 1 .
  • a polydispersity index (Mw/Mn) of a structurally modified water-soluble glyoxylated polyacrylamide according to the invention is ⁇ 5.0, preferably ⁇ 4.0 and more preferably ⁇ 3.5.
  • a typical mass average molar mass (Mw) of a structurally modified, water-soluble glyoxylated polyacrylamide according to the invention is at least 0.5 Mg/mol, preferably at least 0.7 Mg/mol and more preferably at least 1 .0 Mg/mol.
  • a number average molar mass (Mn) of a structurally modified, water-soluble glyoxylated polyacrylamide according to a typical embodiment of the invention is at least 2.8 x 10 5 g/mol, preferably at least 3.0 x 10 5 g/mol and more preferably at least 3.2 x 10 5 g/mol.
  • Mw, Mn and polydispersity index (Mw/Mn) are determined by GPC. The GPC system and measurement conditions are described more detailed in Example 1 . It is believed that the high molecular weight in combination with the novel structure of the structurally modified water-soluble polymer according to the invention facilitates strong interaction with the inorganic siliceous microparticles yet without over-flocculating the papermaking system in ever increasing polymer dosage. The opportunity to increase dosage without over- flocculation is especially advantageous when the fibre suspension contains detrimental substances and/or high conductivities.
  • exceptional drainage improvement for fibre suspensions comprising recycled fiber materials has been discovered when the structurally modified, water-soluble glyoxylated polyacrylamide according to the invention is used with inorganic siliceous microparticles. Therefore, the benefit of the invention is to improve the drainage of fibre suspensions comprising recycled fibre material and thus comprising even high amounts of detrimental substances such as dissolved solids and/or high ash content.
  • an exceptional drainage improvement can be expected for fibre suspensions comprising high filler content when the structurally modified, water-soluble glyoxylated polyacrylamide according to the invention is used with inorganic siliceous microparticles. Therefore, the benefit of the invention is to improve the drainage of fibre suspensions comprising high filler content.
  • All paper products and the like may benefit from the drainage system according to the present invention, especially recycled paperboard, tissue/towel, and printing and writing papers, just to name a few.
  • This invention is for use of structurally modified, water-soluble glyoxylated polyacrylamide as boosters for inorganic siliceous microparticle drainage aids and as paper strength resins.
  • FIGS 1 to 3 show the results of dynamic drainage analyser (DDA) studies according to Examples 2 to 4.
  • Standard viscosity is used herein to reflect or indicate the molecular weights for polymers having molecular weights more than 1 million Dalton. Standard viscosity as used herein is determined with a Brookfield DVII T viscometer. A 0.2 weight-% water solution of a polymer is diluted to 0.1 weight-% concentration with 1 1 .7 weight-% NaCI solution to make a 50:50 solution of the polymer and 1 1 .7 weight-% NaCI in a 250 ml_ beaker, i.e. 0.1 weight-% polymer concentration in 1 M NaCI.
  • pH of the 0.15 weight-% salt dilute polymer solution is adjusted to pH 8.0 - 8.5 by dilute NaOH solution or H 2 S0 4 solution before the viscosity measurement.
  • 19 ml of solution is taken using a graduated cylinder, and slowly poured into the Brookfield SV chamber and the temperature of the SV solution in the chamber is adjusted to 25 °C.
  • the viscosity of 0.1 weight-% solution is measured at 25 °C, using spindle #00, the spindle speed being 60 RPM.
  • the unit of SV is centipoise (cP).
  • Bulk viscosity is used herein to indicate the viscosity of an aqueous solution of a polymer in the prevailing solids content. As used herein, bulk viscosity is determined with a Brookfield DVII T viscometer at 25 °C. The unit of bulk viscosity is equally centipoise (cP).
  • a backbone of a polyacrylamide refers in this disclosure to the main chain of the polyacrylamide which is a result of the (co)polymerisation reaction of acrylamide, and optionally any cationic, anionic or non-ionic monomers copolymerisable with acrylamide.
  • Anionic monomers are monomers possessing a negative net charge
  • cationic monomers are monomers possessing a positive net charge
  • non-ionic monomers are monomers possessing a net charge of 0.
  • the main chain is substantially linear chain to which all other chains may be regarded as pendant.
  • water-soluble is understood so that the glyoxalated polyacrylamide is miscible with water.
  • the glyoxalated polyacrylamide is preferably fully dissolved and the obtained glyoxalated polyacrylamide solution is preferably essentially free from discrete polymer particles or granules. Excess of water means that the obtained glyoxalated polyacrylamide solution is not a saturated solution.
  • degradation agent refers to any compound or mixture of compounds which is capable of reducing the standard viscosity of a polyacrylamide when in an aqueous environment by cleaving the backbone of the polyacrylamide, i.e. the main chain of the acrylamide polymer, into fragments. The effect of the degradation agent and the cleavage of the polymer backbone can be seen in the decreasing viscosity of the aqueous medium comprising the polyacrylamide.
  • cross-linking refers to covalently linking two target groups present in the polyacrylamide and/or in the fragments thereof, which fragments are resulted from the cleaving of the polyacrylamide backbone.
  • glyoxal is a preferred cross-linking agent for covalently linking cleaved fragments of the acrylamide polymer to other said fragments and/or to the backbone of the acrylamide polymer.
  • the present invention provides a process for manufacturing paper product or the like, wherein a drainage system is incorporated into a fibre suspension, which drainage system comprises inorganic siliceous microparticles and a structurally modified, water-soluble glyoxylated polyacrylamide having an intrinsic viscosity at least 0.5 dl/g, preferably at least 0.7 dl/g and more preferably at least 1 .0 dl/g, as determined by GPC.
  • the structurally modified, water-soluble glyoxylated polyacrylamide is obtained by
  • the glyoxylated polyacrylamide may be obtained in the form of an aqueous, non-gelled composition surprisingly expressing a synergistic interaction with inorganic siliceous microparticles providing an exceptional drainage improvement. Furthermore, the structurally modified, water-soluble glyoxylated polyacrylamide may provide an excellent strength response.
  • the polyacrylamide used in the method for preparing a structurally modified water-soluble glyoxylated polyacrylamide has a standard viscosity of at least 1 .2 cP, preferably at least 1 .5 cP, more preferably at least 2.0 cP, measured at 0.1 weight-% polymer concentration in 0.1 M NaCI, at 25 °C, pH 8.0-8.5, using Brookfield DVII T viscometer.
  • Higher standard viscosity of the polyacrylamide corresponds to higher molecular weight.
  • High molecular weight polymers are available in higher solids content, even as dry powders.
  • the polyacrylamide backbone being subjected to degradation agent has higher molecular weight
  • the structurally modified water-soluble polyacrylamide obtained after cross- linking with glyoxal may have higher molecular weight.
  • the polyacrylamide has a molecular weight of at least 2 million Dalton, preferably at least 5 million Dalton or even more preferably at least 10 million Dalton.
  • the polyacrylamide has a molecular weight in the range of 10 to 20 million Dalton, or in the range of 10 to 15 million Dalton.
  • the polyacrylamide is a dry polymer which allows for improved logistics both cost and product robustness for challenging climate conditions.
  • the degradation agent and the cross- linking agent may be pre-mixed together before addition, or they may be added separately such as sequentially, the degradation agent being added before glyoxal as the cross-linking agent.
  • the additions of the degradation agent and the glyoxal may also overlap, in which case the addition of the degradation agent may continue when the glyoxal addition is started. In this way the degradation agent starts breaking of the polyacrylamide backbone earlier than the cross-linking starts, but breaking of the backbone into fragments still continue at same time with cross-linking reaction.
  • the polyacrylamide and the degradation agent are introduced into the aqueous composition first, and the cross-linking agent, preferably glyoxal, is introduced thereto subsequently.
  • the degradation agent starts breaking of the polyacrylamide backbone before the cross- linking starts.
  • the degradation agent continues breaking of the polyacrylamide backbone in parallel with cross-linking e.g. by the glyoxylation, until all of the degrading power of the degradation agent has been consumed or quenched.
  • Cross-linking reaction may be an equilibrium reaction, as is the case for e.g. glyoxylation.
  • the bulk viscosity of the aqueous composition of the cross-linking and degrading polyacrylamide evolves until the degrading power of the degradation agent has been consumed or quenched and the cross-linking, preferably glyoxylation, reaction has reached an equilibrium.
  • the polyacrylamide and the degradation agent is dissolved in the aqueous medium simultaneously as a dry mixture.
  • the dry mixture may be provided by mixing dry polyacrylamide and dry degradation agent. This embodiment has the additional utility that the dry mixture has good storage stability, is easily and cost-efficiently transported to the site of use, and the cleaving of the backbone of the polyacrylamide does not start before the dry mixture is brought into an aqueous environment.
  • the degradation agent is mixed into a further aqueous medium and then combined with the polyacrylamide in the aqueous medium.
  • dry polyacrylamide is dissolved in an aqueous solution of the degradation agent.
  • step (iii) of the method is initiated after all degradation agent has been incorporated to the aqueous medium in step (ii) of the method, i.e. cross-linking of the polyacrylamide subjected to cleaving is initiated to the aqueous medium only after all degradation agent has been incorporated to the aqueous medium.
  • at least step (iii) of the method, i.e. crosslinking of the polyacrylamide subjected to cleaving is conducted on site of the use of the aqueous composition of the structurally modified, water-soluble glyoxylated polyacrylamide.
  • the degradation agent used in the method for preparing a structurally modified, water-soluble glyoxylated polyacrylamide may be any compound or mixture of compounds capable of breaking, i.e. cleaving the backbone of the polyacrylamide in an aqueous environment into smaller polymeric fragments. This has the effect of reducing the standard viscosity of the polyacrylamide, and the effect of reducing the bulk viscosity of an aqueous composition comprising the polyacrylamide.
  • the degradation agent may be any compound or mixture of compounds capable of reducing the standard viscosity of the polyacrylamide by cleaving the backbone of the polyacrylamide into polymeric fragments thereof.
  • the degradation agent used in the method for preparing a structurally modified, water-soluble glyoxylated polyacrylamide may be selected from compounds or mixtures of compounds capable of reducing the standard viscosity of the polyacrylamide by at least 5 %, advantageously by at least 10 %. Mere hydrolysis of side groups of e.g. an acrylamide based copolymer does not cause sufficient reduction of viscosity.
  • the degradation agent is selected from oxidizing degradation agents, reducing degradation agents, or any combinations thereof.
  • the degradation agent is a reducing degradation agent.
  • the oxidizing degradation agent is selected from the group consisting of sodium percarbonate, sodium hypochlorite, sodium persulfate, potassium persulfate, ammonium persulfate, hydrogen peroxide, sodium perborate, or any combinations thereof.
  • the reducing degradation agent is selected from the group consisting of an iron compound, tin(ll) chloride, sodium borohydride (NaBH 4 ), sodium dithionite, or any combinations thereof. Reducing degradation agents may provide faster degradation than oxidizing agents.
  • the degradation agent may also be an enzymatic degradation agent, such as an oxidase.
  • the degradation agent is selected from the group consisting of an iron compound, sodium borohydride (NaBH 4 ), sodium dithionite, sodium percarbonate, sodium persulfate, potassium persulfate, ammonium persulfate, hydrogen peroxide, sodium perborate, to avoid incorporating chlorides.
  • an iron compound sodium borohydride (NaBH 4 ), sodium dithionite, sodium percarbonate, sodium persulfate, potassium persulfate, ammonium persulfate, hydrogen peroxide, sodium perborate, to avoid incorporating chlorides.
  • the degradation agent comprises an iron compound.
  • This compound is advantageously a ferrous compound such as a ferrous salt or a ferric compound such as a ferric salt, these being available in dry powder form.
  • Iron compounds are generally environmentally friendly compounds.
  • ferrous is used according to its customary meaning to indicate a divalent iron compound (+2 oxidation state or Fe(ll)).
  • ferric is used according to its customary meaning to indicate a trivalent iron compound (+3 oxidation state or Fe(lll)).
  • the ferrous salt comprises an organic anion, an inorganic anion, or a mixture thereof.
  • the ferrous salt is ferrous citrate, ferrous chloride, ferrous bromide, ferrous fluoride, ferrous sulfate, ammonium iron sulfate or any combinations thereof.
  • the iron- containing degradation agent comprises ferrous sulfate.
  • the ferric salt comprises an organic anion, an inorganic anion, or a mixture thereof.
  • the ferric salt is ferric citrate, ferric chloride, ferric bromide, ferric fluoride, ferric sulfate, and any combinations thereof.
  • the most advantageous polymer degradation agent for use in the present disclosure is iron(ll)sulfate.
  • Iron sulfate in particular ferrous sulfate, is able to dissolve and degrade at ambient pulp suspension conditions whereas the other degradation agents require elevated temperature to achieve the same polymer degradation effectiveness.
  • another polymer degradation agent may be used, such agent being advantageously selected from the group consisting of persulfates, peroxides, sodium chlorite, tin(ll)chloride and percarbonates.
  • the amount of the degradation agent varies from 0.5 to 15 weight-% of the polyacrylamide, preferably 2.5 to 10 weight-%, calculated as dry.
  • the expression calculated as dry includes the crystal water. In this range the degradation of the polymer backbone proceeds adequately, yet controllably, so as to avoid the degradation from proceeding too extensively thereby causing too low molecular weight.
  • the amount of the degradation agent is expressed excluding the potential bound water.
  • the polyfunctional cross-linking agent is a dialdehyde cross-linking agent providing aldehyde functionality to the cross-linked polyacrylamide, rendering the polyacrylamide cellulose-reactive.
  • the cross-linking agent is a glyoxal, which is a common commercially available dialdehyde. Glyoxal may provide faster cross-linking reaction compared e.g. to dialdehydes having higher chain length / number of carbon atoms.
  • the cross-linking reaction of preparing a structurally modified, water-soluble glyoxylated polyacrylamide, such as glyoxylation itself in the present disclosure may be any known or obvious glyoxalation sequence.
  • An example of a representative disclosure for carrying out glyoxylation is presented in US 8,435,382.
  • conventional GPAM is prepared by reacting a cationic polyacrylamide backbone, with glyoxal in a slightly alkaline aqueous solution, pH from about 7 to 8, and by stabilizing under acidic conditions pH from about 3 to 6.
  • the amount of glyoxal is from 5 to 80 weight-%, preferably from 8 to 60 weight-%, more preferably from 8 to 30 weight-% of the acrylamide polymer, calculated as dry. Amounts above 80 weight-% may provide extremely high reaction speed. On the other hand amounts below 5 weight-% may provide unreasonably slow reaction rate. Amounts up to 60 weight-%, especially up to 30 weight-%, may provide reaction speed that is convenient to control.
  • glyoxal to acrylamide unit molar ratio is at least 0.4.
  • glyoxal to acrylamide unit molar ratio is from 0.4 to 0.70.
  • the polyacrylamide used in said method for preparing a structurally modified, water-soluble polymer is a copolymer originating from at least 50 mol-% of acrylamide monomers.
  • Dialdehyde cross-linking agents such as glyoxal may react with the amide group of the acrylamide.
  • the acrylamide monomer level of at least 50 mol-% provides good cross-linking rate and level of cross-linking thereby increasing the molecular weight of the cross-linked polymer, and thus the strength performance thereof in papermaking.
  • the polyacrylamide is a cationic polyacrylamide, i.e. a (co)polymer having net cationic charge.
  • the polyacrylamide is an anionic polyacrylamide, i.e. a (co)polymer having net anionic charge.
  • the polyacrylamide is a nonionic polyacrylamide, i.e. an acrylamide (co)polymer, such as homopolymer, not having charge. Net cationic charge is preferred as cationic charge binds efficiently to anionic fibres and anionic particles in the fibre suspension.
  • anionic net charge may be preferred, for example when interaction with other, cationic chemicals is desired.
  • non-ionicity may be preferred, for example when presence of charges would interfere other interactions taking place, or when the nonionic polymer comprises hydrophobic monomers as the interacting groups.
  • the polyacrylamide is a copolymer comprising units originating from acrylamide and cationic monomers, wherein cationic monomers are preferably selected from the group consisting of 2- (dimethylamino)ethyl acrylate (ADAM), [2-(acryloyloxy)ethyl] trimethylammonium chloride (ADAM-CI), 2-dimethylaminoethyl methacrylate (MADAM), [2-(methacryloyloxy)ethyl] trimethylammonium chloride (MADAM- Cl), [3-(acryloylamino)propyl] trimethylammonium chloride (APTAC), [3- (methacryloylamino)propyl] trimethylammonium chloride (MAPTAC), and diallyldimethylammonium chloride (DADMAC).
  • ADAM 2- (dimethylamino)ethyl acrylate
  • ADAM-CI 2-dimethylaminoethyl me
  • the cationic monomers are selected from [2-(acryloyloxy)ethyl] trimethylammonium chloride (ADAM-CI), [2-(methacryloyloxy)ethyl] trimethylammonium chloride (MADAM-CI), and diallyldimethyhammonium chloride (DADMAC).
  • ADAM-CI [2-(acryloyloxy)ethyl] trimethylammonium chloride
  • MADAM-CI [2-(methacryloyloxy)ethyl] trimethylammonium chloride
  • DDADMAC diallyldimethyhammonium chloride
  • Quaternary amines are preferred cationic monomers because their charge is not pH dependent. More preferably the cationic monomer is [2-(acryloyloxy)ethyl] trimethylammonium chloride (ADAM-CI).
  • the polyacrylamide is a copolymer originating from at most 30 mol-%, preferably at most 25 mol-%, and more preferably at most 20 mol- % of cationic monomers.
  • Cationic polyacrylamide originating from at most 30 mol-% of cationic monomers have the benefit of easier metering compared to use of highly charged, cationic polymers, the use of which involves the challenge of exact metering and risk of over cationization of the paper machine circuit.
  • the polyacrylamide when synthesizing the polyacrylamide, lowering the amount of cationic monomers and increasing available acrylamide units may enhance the cross-linking rate such as glyoxylation rate of the polyacrylamide and the equilibrium of cross-linking.
  • the cationicity of the polyacrylamide may have an effect on the strength response of paper. For example, cationic charges may decrease strength response of paper with fibre suspensions having low zeta-potential.
  • the polyacrylamide is a copolymer originating from at most 10 mol-% of cationic monomers, based on the total monomer content. Typically, the polyacrylamide is a copolymer originating from 8-25 mol-% of cationic monomers.
  • the polyacrylamide used for preparing a structurally modified, water-soluble glyoxylated polyacrylamide may be an acrylamide containing polymer including acrylamide homopolymers, copolymers, and terpolymers including polyacrylamide; polyacrylamide derivatives; partially hydrolyzed polyacrylamide; partially hydrolysed polyacrylamide derivatives; methacrylamide homopolymers, copolymers, and terpolymers; diacetone acrylamide polymers; N-methylolacrylamide polymers; friction-reducing acrylamide polymers; and any combinations thereof.
  • the polyacrylamide is PVAm obtained by partial or complete hydrolysis of poly(N- vinylformamide).
  • the method for manufacturing the aqueous composition of a structurally modified, water-soluble glyoxylated polyacrylamide further comprises buffering the aqueous medium before introducing glyoxal thereto.
  • the pH of the aqueous composition is subsequently adjusted by buffering the composition by adding buffer solution thereto.
  • the pH of the aqueous medium is adjusted to a value of at least 7.0, preferably to a value between 7.0 and 7.5, providing optimal pH for the cross-linking reaction of glyoxal.
  • the higher the pH the higher is the degradation rate, especially when using reducing agents such as ferrous sulphate.
  • the aqueous composition of a structurally modified water-soluble glyoxylated polyacrylamide has a bulk viscosity of at most 50 cP, preferably at most 20 cP, more preferably at most 15 cP, measured at 25 °C using Brookfield DVII T viscometer.
  • the bulk viscosity is at most 50 cP, the composition is easier to dose and over-flocculation is easier to avoid.
  • the solids content of the aqueous composition of the structurally modified water-soluble glyoxylated polyacrylamide may be at most 5 weight-%, preferably at most 3 weight-%, and more preferably around 2 weight-%. By using such low solids contents high viscosities may be avoided thereby making the composition easier to handle and mix with the fibre suspension.
  • fibre suspension into which drainage system is incorporated, is understood as an aqueous suspension which comprises fibres and optionally fillers.
  • the fibre suspension may also be called pulp slurry or pulp suspension.
  • the fibre suspension may comprise recycled fibre material and/or paper machine broke.
  • the recycled fibre material is selected from old corrugated cardboard, mixed office waste, double liner kraft, or any mixtures thereof.
  • old corrugated cardboard OCC
  • DS OCC double sorted corrugated cardboard
  • mixed office waste MOW
  • double lined kraft a material comprising clean sorted unprinted corrugated cardboard cartons, boxes, sheet or trimmings, e.g. of kraft or jute liner.
  • Presence of any of these in the fibre suspension decrease drainage and paper strength, and provide a substantial load of dissolved and colloidal substances to the process, interfering with the performance, especially of cationic retention and dry-strength agents, and wet-strength resins, as well as causing deposits.
  • Conventionally increased washing has been used to reduce colloidal substances, however this operation is not desired nor typically available in closed systems.
  • a fibre suspension comprises at least 20 weight-%, preferably at least 30 weight-%, more preferably at least 40 weight-%, calculated as dry of recycled fibre material.
  • the drainage system of the present disclosure performs when using high amounts of recycled fibre materials, even up to 100 weight-%.
  • the fibre suspension has a conductivity of at least 2.0 mS/cm, preferably at least 2.5 mS/cm, and more preferably at least 3.0 mS/cm, as measured at the headbox of the papermaking process.
  • the conductivity of the fibre suspension may be even higher, such as at least 5.0 mS/cm.
  • the drainage system according to the invention may perform even when added into a fibre suspension having conductivity of 10 mS/cm. It has been observed that the drainage system according to the invention has good drainage performance in these conductivities, compared to a performance of traditional paper chemicals which start to lose their performance already at slightly elevated conductivities. The present invention continues performing well even in high conductivities.
  • the fibre suspension comprises ash at least 10 weight-%, preferably at least 15 weight-%, more preferably at least 20 weight-% based on dry total solids.
  • the ash may originate from added filler, and/or from fillers and/or mineral pigments of recycled fibre material, and/or from paper machine broke. The amount of ash is calculated by drying the stock, and measuring the ash content. Standard ISO 1762, at temperature 525 °C is used for ash content measurements.
  • Ash may be any filler or pigment conventionally used in paper and board making, such as ground calcium carbonate, precipitated calcium carbonate, clay, talc, gypsum, titanium dioxide, synthetic silicate, aluminium trihydrate, barium sulphate, magnesium oxide or their any of mixtures.
  • the drainage system of the invention provides improved drainage and retention for high ash content fibre suspensions compared to the existing systems.
  • a drainage system is used for improving drainage of a fibre suspension comprising recycled fibre materials and having a conductivity of at least 2.0 mS/cm.
  • a drainage system is used for improving drainage of a fibre suspension comprising recycled fibre materials including mixed office waste (MOW).
  • Fibre suspensions comprising MOW have typically very high stock conductivity level of at least 2.0 mS/cm, or higher.
  • Recycled fibre materials comprising MOW have lower quality than e.g. chemical pulp also in other terms than conductivity, such as elevated content of ash and stickies, and lower fibre strength, increasing disturbances in the papermaking process.
  • the drainage system for manufacture of paper product or the like comprises inorganic siliceous microparticles, such as silica or bentonite or mixture thereof.
  • inorganic siliceous microparticles are selected from silica based particles, silica microgels, colloidal silica, silica sols, silica gels, polysilicates, aluminosilicates, polyaluminosilicates, borosilicates, polyborosilicates, zeolites and swellable clays, such as bentonite.
  • inorganic siliceous microparticles are silica sols. These embodiments may provide improved retention and drainage, compared to other inorganic siliceous microparticles.
  • Silica sols may be characterized by their specific surface area (SSA) and/or level of aggregation or structuring. High SSA and structured or aggregated silica sols are beneficial in applications where flocculation is desirable.
  • the degree of aggregation is normally characterized by the S-value, which is a measure of the silica (as percent) in the disperse phase.
  • the silica sol has either an S-value less than 40 %, preferably less than 35 %, or a specific surface area of at least 800 m 2 /g, preferably at least 900 m 2 /g. These embodiments may provide further improved retention and drainage compared to silica sols with higher S-values or lower specific surface areas.
  • the silica sol has both an S-value less than 40 % and a specific surface area of at least 800 m2/g, preferably the S-value is less than 35 % and the specific surface area is at least 800 m2/g or at least 900 m2/g. These embodiments may provide even further improved retention, and drainage compared to silica sols with either the S-value or the specific surface area outside said ranges.
  • the structurally modified, water-soluble glyoxylated polyacrylamide and inorganic siliceous microparticles may be introduced to the fibre suspension throughout the paper making process prior to the headbox of the paper machine.
  • the inorganic siliceous microparticles and the structurally modified, water-soluble glyoxylated polyacrylamide may be added simultaneously into a fibre suspension.
  • the inorganic siliceous microparticles and the structurally modified, water-soluble glyoxylated polyacrylamide are added sequentially into a fibre suspension.
  • the structurally modified, water-soluble glyoxylated polyacrylamide polymer is added to a fibre suspension before the addition of the inorganic siliceous microparticles.
  • the structurally modified, water-soluble glyoxylated polyacrylamide has more time to adsorb onto the fibres before delivering to the headbox and the commencement of sheet forming, thereby providing higher strength improvement to the paper.
  • a fibre suspension having a consistency of above 20 g/l is called thick stock, before it is diluted with white water into thin stock.
  • the structurally modified, water-soluble glyoxylated polyacrylamide is added into the fibre suspension at a consistency of above 20 g/l.
  • Examples of possible addition points in a process for manufacturing paper or the like include any point after a machine chest, such as the suction side of the machine chest pump, up to the point of thick stock dilution to obtain thin stock.
  • the structurally modified, water-soluble glyoxylated polyacrylamide has not only more time to adsorb onto the fibres, but also is in closer proximity with the fibres due to the higher consistency, thereby providing opportunity for greater interaction, which provides a strength improvement to the paper.
  • the inorganic siliceous microparticles are added into the fibre suspension after the last point of high shear before a headbox, preferably between a pressure screen and a headbox of the process. This embodiment has the benefit of improved bridging of sheared polymer-fibre floes by the inorganic siliceous microparticles, thereby improving retention and drainage.
  • Addition sequences may also include application of the structurally modified, water-soluble glyoxylated polyacrylamide after the inorganic siliceous microparticles.
  • the drainage system further comprises a cationic flocculant.
  • the cationic flocculant may be a copolymer of acrylamide and cationic monomers, or cationic starch.
  • the cationic flocculant is a high molecular weight copolymer of acrylamide and cationic monomers (HMW CPAM)
  • the cationic flocculant may be linear or branched.
  • the cationic flocculant may be added directly to the fibre suspension or it may be added first to an aqueous flow, which is later combined with the fibre suspension at any suitable location, for example at any suitable wet end location.
  • time points or locations include before or after refining of the fibre suspension, at the fan pump, before or at the head box.
  • the cationic flocculant may be added into the fibre suspension in an amount of 0.1 - 2 lb (dry solids)/ton dry fibre suspension.
  • a structurally modified, water-soluble glyoxylated polyacrylamide is added into the fibre suspension, then a cationic flocculant is added, followed by inorganic siliceous microparticles.
  • inorganic siliceous microparticles comprising silica sol is added into the fibre suspension in an amount of 0.1 to 2.0 lb (dry solids)/ton dry fibre suspension, such as 0.15 to 1 .5 lb (dry solids)/ton dry fibre suspension, or 0.2 to 1 .0 lb (dry solids)/ton dry fibre suspension.
  • inorganic siliceous microparticles comprising bentonite is added to the fibre suspension in an amount of 0.2 to 10 lb (dry solids)/ton dry fibre suspension, such as 2 - 8 lb (dry solids)/ton dry fibre suspension, or 3 - 5 lb (dry solids)/ton dry fibre suspension.
  • the slurry of inorganic siliceous microparticles, such as bentonite slurry or silica sol may be further diluted before addition to the fibre suspension, if needed.
  • the structurally modified, water-soluble glyoxylated polyacrylamide is added to the fibre suspension in an amount of 1 - 20 lb (dry solids)/ton dry fiber suspension.
  • the invention relates to a process for the production of paper product or the like from a fibre suspension treated with the process according to the invention, wherein the treated fibre suspension is formed into a fibrous web and drained. The steps of forming a fibre suspension, draining and drying may be carried out in any suitable manner generally known to those skilled in the art.
  • the aim of this example was to characterize glyoxylated polyacrylamide (GPAM) samples according to the invention in terms of molecular weight distribution (MWD) and moments (Mn, Mw, Mz) and intrinsic viscosity (IV) by using Gel Permeation Chromatography (GPC).
  • MFD molecular weight distribution
  • Mn, Mw, Mz moments
  • IV intrinsic viscosity
  • dn/dc where CF is a constant of the detector, Rl is the signal measured and dn/dc is the refractive index increment of the polymer in the NaN0 3 solvent used.
  • the structurally modified, water-soluble glyoxylated polyacrylamide according to the invention exhibits far higher intrinsic viscosity, indicating a completely different molecular structure compared to a conventional GPAM (FB3000, Kemira Oyj). Additionally the polydispersity index is lower suggesting lower heterogeneity of sizes of the molecules.
  • a 100% recycled fibre stock was diluted with white water to obtain a fibre suspension of 0.6 weight-% solids content.
  • the mixed office waste (MOW) 100% recycled fibre stock had a very low freeness of 248 ml measured by Canadian Freeness Tester.
  • the conductivity of the fibre suspension was high, 2800 ps/cm.
  • As 400 ml_ diluted furnish was chemically treated in a Dynamic Drainage Analyzer (DDA) for vacuum drainage test.
  • the vacuum of DDA was set in the range of -200 mbar to -300 mbar. The time needed to show a vacuum break was considered as the indication of drainage.
  • the permeability expressed in pressure units (mbars) was also recorded and it is the indication of sheet porosity.
  • the filtrate was used for the measurement of turbidity by a Hach turbidimeter as an indication of retention.
  • each tested program contained 0.5 lb (dry solids)/ton silica sol (SSA > 900 m 2 /g, S-value ⁇ 35 %) and 0.9 lb (dry solids)/ton high molecular weight cationic flocculant comprising a copolymer of acrylamide and cationic monomers (HMW CPAM).
  • the tested programs further contained either no performance booster; or conventional GPAM FB3000; low molecular weight cationic flocculant comprising a copolymer of acrylamide and cationic monomers (LMW PAM); or the structurally modified, water-soluble glyoxylated polyacrylamide polymer according to the invention (Novel GPAM), as the booster.
  • the structurally modified glyoxylated polyacrylamide exhibited much more interaction with the silica sol than the other cationic polymers in terms of the drainage time.
  • the invention achieved an exceptional drainage improvement as shown in Figure 1 .
  • Example 2 A similar study was performed as in Example 2, using similar fibre suspension, conditions and procedures.
  • To the fibre suspension was added either no processing aid program; or high molecular weight cationic flocculant comprising a copolymer of acrylamide and cationic monomers (HMW CPAM); HMW CPAM and silica; HMW CPAM, silica and conventional GPAM (FB3000); or HMW CPAM, silica and the structurally modified, water-soluble glyoxylated polyacrylamide according to the invention (Novel GPAM), as the test program.
  • HMW CPAM high molecular weight cationic flocculant comprising a copolymer of acrylamide and cationic monomers
  • HMW CPAM HMW CPAM and silica
  • HMW CPAM HMW CPAM, silica and conventional GPAM (FB3000)
  • Novel GPAM the structurally modified, water-soluble glyoxylated polyacrylamide according to the invention
  • the dosages were 0.5 lb (dry solids)/ton dry paper of silica sol (SSA > 900 m 2 /g, S-value ⁇ 35 %), 0.9 lb (dry solids)/ton dry paper of HMW CPAM, and 3 lb (dry solids)/ton dry paper of FB3000 or the structurally modified, water-soluble glyoxylated polyacrylamide according to the invention (Novel GPAM).
  • Novel GPAM the structurally modified, water-soluble glyoxylated polyacrylamide according to the invention
  • the program using HMW CPAM and silica sol boosted with the structurally modified, water-soluble glyoxylated polyacrylamide according to the invention (Novel GPAM), provided an exceptional drainage improvement when compared to any of the tested programs.
  • a drainage improvement of this magnitude is highly exceptional, especially taking into account the low quality recycled fibre stock used in the preparation of the fibre suspension, and the high conductivity thereof, about 3 mS/cm.
  • Example 4 Yet another similar study was performed as in Example 2, using similar fibre suspension, conditions and procedures, but this time the fibre suspension was sized with ASA emulsion 5.5 lb (as is)/ton dry paper. ASA emulsion was prepared by a ratio of 1 : 1 for ASA: liquid starch as is.
  • conventional GPAM FB3000
  • the structurally modified, water-soluble glyoxylated polyacrylamide according to the invention Novel GPAM
  • conventional GPAM and silica sol FB3000 with silica
  • the dosages were 0.5 lb (dry solids)/ton dry paper of silica sol (SSA > 900 m 2 /g, S-value ⁇ 35 %), and 6 lb (dry solids)/ton dry paper of FB3000 or the structurally modified, water-soluble polyacrylamide polymer according to the invention.
  • the structurally modified, water-soluble glyoxylated polyacrylamide according to the invention alone achieved comparable drainage results to a program of conventional GPAM and silica sol.
  • this program yielded the lowest drainage time, i.e. best result of drainage. Additionally it can be seen that this program performs well even without the use of HMW CPAM.

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Abstract

La présente invention concerne un processus amélioré de fabrication de produit en papier ou similaire. Le processus comprend l'incorporation d'un système de drainage dans la suspension fibreuse, lequel système de drainage comprend des microparticules siliceuses inorganiques et un polyacrylamide glyoxylé hydrosoluble structuralement modifié ayant une viscosité intrinsèque d'au moins 0,5 dl/g, de préférence d'au moins 0,7 dl/g et de préférence encore d'au moins 1,0 dl/g, telle que déterminée par chromatographie par perméation de gel (GPC).
PCT/US2016/054630 2016-09-30 2016-09-30 Système de drainage et processus de fabrication de produit en papier ou similaire WO2018063273A1 (fr)

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Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1999050500A1 (fr) * 1998-03-31 1999-10-07 Callaway Corporation Amelioration de la retention et de l'essorage dans la fabrication de papier fin alcalin
WO2000034584A1 (fr) * 1998-12-07 2000-06-15 Hercules Incorporated Polyacrylamides glyoxales utilises comme agents de renforcement du papier
US20020198306A1 (en) * 2001-06-12 2002-12-26 Duncan Carr Aqueous composition
US20100326615A1 (en) * 2009-06-29 2010-12-30 Buckman Laboratories International, Inc. Papermaking And Products Made Thereby With High Solids Glyoxalated-Polyacrylamide And Silicon-Containing Microparticle
US8435382B2 (en) 2007-06-15 2013-05-07 Buckman Laboratories International, Inc. High solids glyoxalated polyacrylamide
WO2014154937A1 (fr) * 2013-03-26 2014-10-02 Kemira Oyj Procédé pour la production de papier ou de carton
WO2015038901A1 (fr) * 2013-09-12 2015-03-19 Ecolab Usa Inc. Procédé et compositions pour la fabrication du papier
WO2015075318A1 (fr) * 2013-11-22 2015-05-28 Kemira Oyj Procédé pour augmenter la résistance du papier

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1999050500A1 (fr) * 1998-03-31 1999-10-07 Callaway Corporation Amelioration de la retention et de l'essorage dans la fabrication de papier fin alcalin
WO2000034584A1 (fr) * 1998-12-07 2000-06-15 Hercules Incorporated Polyacrylamides glyoxales utilises comme agents de renforcement du papier
US20020198306A1 (en) * 2001-06-12 2002-12-26 Duncan Carr Aqueous composition
US8435382B2 (en) 2007-06-15 2013-05-07 Buckman Laboratories International, Inc. High solids glyoxalated polyacrylamide
US20100326615A1 (en) * 2009-06-29 2010-12-30 Buckman Laboratories International, Inc. Papermaking And Products Made Thereby With High Solids Glyoxalated-Polyacrylamide And Silicon-Containing Microparticle
WO2014154937A1 (fr) * 2013-03-26 2014-10-02 Kemira Oyj Procédé pour la production de papier ou de carton
WO2015038901A1 (fr) * 2013-09-12 2015-03-19 Ecolab Usa Inc. Procédé et compositions pour la fabrication du papier
WO2015075318A1 (fr) * 2013-11-22 2015-05-28 Kemira Oyj Procédé pour augmenter la résistance du papier

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