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
  • D21H17/63—Inorganic compounds
  • D21H17/67—Water-insoluble compounds, e.g. fillers, pigments
  • D21H17/675—Oxides, hydroxides or carbonates
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
  • D21H17/20—Macromolecular organic compounds
  • D21H17/21—Macromolecular organic compounds of natural origin; Derivatives thereof
  • D21H17/24—Polysaccharides
  • D21H17/28—Starch
  • D21H17/29—Starch cationic
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
  • D21H17/20—Macromolecular organic compounds
  • D21H17/21—Macromolecular organic compounds of natural origin; Derivatives thereof
  • D21H17/24—Polysaccharides
  • D21H17/31—Gums
  • D21H17/32—Guar or other polygalactomannan gum
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
  • D21H17/20—Macromolecular organic compounds
  • D21H17/33—Synthetic macromolecular compounds
  • D21H17/34—Synthetic macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
  • D21H17/41—Synthetic macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds containing ionic groups
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
  • D21H17/20—Macromolecular organic compounds
  • D21H17/33—Synthetic macromolecular compounds
  • D21H17/34—Synthetic macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
  • D21H17/41—Synthetic macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds containing ionic groups
  • D21H17/44—Synthetic macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds containing ionic groups cationic
• • 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
  • 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
  • D21H21/00—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties
  • D21H21/50—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties characterised by form
  • D21H21/52—Additives of definite length or shape
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H23/00—Processes or apparatus for adding material to the pulp or to the paper
  • D21H23/02—Processes or apparatus for adding material to the pulp or to the paper characterised by the manner in which substances are added

Definitions

• the present invention relates to the use of a precipitated calcium carbonate (PCC) suspension, and in particular, a suspension of ultrafine PCC particles, in papermaking.
• PCC precipitated calcium carbonate
• the present invention also relates to an improved method for dewatering and an improved process for the production of paper.
• colloidal silica such as that associated with the various Compozil® systems, in the production of paper to obtain improved retention and dewatering.
• a suspension comprising ultrafine PCC particles is utilized in the manner analogous to the previously employed colloidal silica. It has been surprisingly discovered that these suspensions can provide, in combination with agents such as cationic polymers, a substantial improvement of the retention and dewatering in the production of paper. The improvements in dewatering can, for example, allow the speed of the papermaking machine to be increased. Accordingly, the economics of the papermaking process can be substantially improved.
• the primary function of the PCC particles is the ability to provide a desired charge, e.g., typically a negative charge, thereby enhancing the charge characteristics of the system.
• one aspect of the invention relates to a suspension of ultrafine PCC particles.
• ultrafine it is meant particles having a mean particle size of less than 200nm, preferably less than 100 nm with particles sized on the order of 25-75 nm being suitable.
• the PCC suspension according to the present invention can comprise ultrafine PCC particles such as those available from Solvay SA under the SOCAL® trademark. Specific examples of such ultrafine particles are illustrated in the following chart:
• the ultrafine particles employed in the present invention typically have a higher surface area and a higher charge density which make them particularly suitable for use in the invention.
• the ultrafine particles can be employed in an aqueous suspension in an amount suitable to provide the desired dewatering improvement.
• a suitable suspension includes about 10 % by weight of the ultrafine particles in an aqueous suspension.
• the suspension can be produced by techniques recognized in the art and need not be described in detail here.
• suspensions according to the present invention can be used as a replacement for colloidal silica in paper-making processes.
• paper-making processes are well recognized in the art, they need not be described in detail.
• the inventors offer the following remarks regarding the paper-making suspensions that are suitable for the present invention.
• the present invention can employ a variety of paper-making suspensions containing a variety of cellulose-containing fibers.
• the suspensions should typically contain a suitable amount of fibers to provide the desired consistency at the various points of the paper making process.
• the consistency of the fiber in thick stock can typically be on the order of 3%, of thin stock on the order of 0.5 to 1 % and later, at the drying section, at least about 50 percent by weight of such fibers, based on dry material. Such amounts are well recognized in this field.
• the components can for example be used for suspensions of fibers from chemical pulp, such as sulphate and sulphite pulp, thermomechanical pulp, refiner pulp or groundwood pulp from both hardwood and softwood and can also be used for suspensions based on recycled fibers.
• the suspension can also contain mineral fillers, such as for example kaolin, titanium dioxide, gypsum, chalk and talcum.
• paper and paper-making do of course not include solely paper and its production but also other cellulose fiber containing products in sheet or web form such as pulp sheets, board and cardboard and their production.
• cationic polymers suitable for use in the invention include natural, e.g. based on carbohydrates, and synthetic polymers.
• suitable polymers include cationic starch, cationic guar gum, cationic acrylamide based polymers, cationic polyethyleneimines, polyamidoamines and poly(diallyldimethyl ammonium chloride).
• the polymers can be used singly or in combination with each other.
• the amount of polymer is to a high degree dependent on the type of this and other effects desired from this.
• synthetic polymers at least 0.01 kg polymer per ton, calculated as dry on dry fibers and optional fillers are usually used.
• amounts of from 0.01 to 3 and preferably from 0.03 to 2 kg per ton are used.
• polymers based on carbohydrates such as cationic starch and cationic guar gum
• amounts of at least 0.1 kg/ton calculated as dry on dry fibers and optional fillers, are used.
• these are used in amounts of from 0.5 to 30 kg/ton and preferably from 1 to 15 kg/ton.
• PCC suspension The other significant component of the paper-making suspension is the PCC suspension.
• the amount of PCC suspension employed in the context of the present invention can vary within wide limits depending on, among other things, the type of suspension being employed.
• the weight ratio of cationic polymer(s) to PCC is typically based on the charge characteristics of the system.
• the other primary factor relates to the economics of the system. It is particularly suitable where the ratio of polymer to PCC in suspension is not less than 10, more preferably not less than 20.
• the paper-making suspensions employed in the present invention can include one or more conventional paper additives such as hydrophobing agents, dry strength agents, wet strength agents etc. Such additives are suitable for, but not significant to, the present invention.
• suitable additive examples include aluminum compounds that can be employed in combination with the PCC suspension and cationic polymers, since it has been found that aluminum compounds may provide a further improvement of retention and dewatering.
• Any known aluminum compound for use in papermaking can be used, for example alum, polyaluminium compounds, aluminates, aluminum chloride and aluminum nitrate.
• the polyaluminium compounds can for example be polyaluminium chlorides, polyaluminium sulphates and polyaluminium compounds containing both chloride and sulphate ions.
• the polyaluminium compounds can also contain other anions than chloride ions, for example anions from sulphuric acid, phosphoric acid, organic acids such as citric acid and oxalic acid.
• the process includes the forming and dewatering of the fiber-containing suspension on a wire to form paper.
• techniques and devices for forming and dewatering the paper-making suspension are well-recognized in the art and need not be described in detail here. It is noted that the PCC suspension can be effectively employed over the entire pH range of 4 to 10 in papermaking, with 4.5 to 8.5 being typically preferred.
• SOCAL® U3 A 10% suspension of SOCAL® U3 was employed. (Stirring speed 1500 rpm, small dissolver) 9854: 10 ml of a 1% hot suspension of starch in a magnetic stirrer was produced (regulation M1).
• the thick material became on a concentration of ⁇ 7.0 g/l by addition of deionized water opposed.
• the setting of the concentration occurs about the regulation of the whole retention (Regulation P.5.).
• salt, NaCl was added to reach a conductivity of 1.2 M / cms.
• Table I illustrates that the results for SOCAL®U3 while, Table II show the results for Compozil ® in tabular form.

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Citations (8)

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• 2004
  • 2004-04-16 EP EP04101574A patent/EP1586704A1/de not_active Withdrawn
• 2005
  • 2005-04-14 WO PCT/EP2005/051660 patent/WO2005100690A1/en active Application Filing
  • 2005-04-14 EP EP05733443A patent/EP1756363A1/de not_active Withdrawn

Patent Citations (8)

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