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
  • D21H11/00—Pulp or paper, comprising cellulose or lignocellulose fibres of natural origin only
  • D21H11/16—Pulp or paper, comprising cellulose or lignocellulose fibres of natural origin only modified by a particular after-treatment
  • D21H11/20—Chemically or biochemically modified fibres
• • 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
  • D21H17/69—Water-insoluble compounds, e.g. fillers, pigments modified, e.g. by association with other compositions prior to incorporation in the pulp or paper
• • 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
  • D21H17/25—Cellulose
  • D21H17/26—Ethers thereof
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
  • D21H17/20—Macromolecular organic compounds
  • D21H17/33—Synthetic macromolecular compounds
  • D21H17/34—Synthetic macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
  • D21H17/41—Synthetic macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds containing ionic groups
  • D21H17/42—Synthetic macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds containing ionic groups anionic
• • 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

Definitions

• the present invention refers to a method of producing a particle or group of particles having a coating of at least two, preferably at least three, outside each other located thin layers of interacting polymers, at which the particle or group of particles is treated in consecutive steps with solutions of the interacting polymers.
• the particles consists at first hand of fibers or filler particles.
• Such a coating modifies the properties of the particles as well as the properties of the products, e g paper and nonwoven, in which the treated fibers and/or filler particles are contained.
• the substrate is herewith immersed altematingly in diluted solutions of a polycation with an intermediate rinsing in order to remove rests of the previous polyion which is not bonded to the substrate.
• the thickness of each deposited layer is described to be between 5-20A. There is no indication that the treated substrates could be particles, such as fibers.
• the object of the present invention is to provide a method for producing particles or groups of particles, especially fibers and/or filler particles, having a coating of at least two, preferably at least three, outside each other located thin layers of interacting polymers, at which the particle or group of particles is treated in consecutive steps with solutions of the interacting polymers. This has been provided by the fact that excess of the previous polymer is removed between each treatment step alternatively that the respective polymer is added only in such an amount in each step that substantially all polymer is adsorbed to the particle surface.
• the particles or groups of particles may be of optional type, however fibers, e g cellulosic fibers, regenerated fibers and different types of synthetic fibers, and filler particles are mainly concerned.
• the interacting polymers are preferably alternating cationic and anionic polyelectro- lytes, but they may also be so called zwitter ions.
• each of said thin layers is preferably between 3 and lOOA, more preferably between 7 and 2 ⁇ A.
• the invention further refers to a paper- or nonwoven product, which contains fibers and/or filler particles produced by the method described above.
• Fig. 1 shows in the form of bar charts the tensile strength index of sheets made of cellulosic fibers with different numbers of applied polymer layers.
• Fig. 2 shows in the form of bar charts the tensile strength index of paper containing different amounts of filler particles treated according to the invention.
• Fig. 3 shows a tensile strength index - opacity diagram for paper containing different amounts of filler particles treated according to the invention.
• Fig. 4 shows in the form of a bar chart the increase of tensile strength of paper containing pulp fibers coated with an anionic and a cationic polymer added at the same time and added separately in six consecutive steps rinsing away the excess of polymer between each step.
• particles or groups of particles are treated with interacting polymers in order to build up thin multilayers of the interacting polymers on the particle surface.
• interacting polymers e g fibers or filler particles
• the technique described in for example above mentioned articles from Thin Solid Films is used in case alternating cationic and anionic polyelectrolytes are used as interacting polymers, with the difference that according to the invention the substrate is fibers or other particles or groups of particles.
• the particles are treated in consecutive steps with solutions of the interacting polymers, at which the treatment time for each step is sufficient for forming a layer of the desired molecular thickness, preferably of the magnitude 5-lO ⁇ A.
• the interaction between the particles can be in the form of electrostatic forces, at which the polymers consist of alternating cationic and anionic polyelectrolytes, or by interaction between nonionic polymers by means of e g dispersion forces or hydrogen bonds. Examples of this type of interaction between nonionic polymers are adsorption of polyethylene oxide on unbleached cellulosic fibers and complex formation between polyethylene oxide and polyacrylic acid.
• the first layer should be a cationic polymer for particles or groups of particles having an anionic surface, which for example is the case for cellulosic fibers, and vice versa.
• Possible excess of the previous polyelectrolyte can be removed between every treatment step, e g by rinsing with water.
• the addition is controlled in such a way that no excess amount of the respective polymer is added in each step, so that substantially all polymer is adsorbed to the particle surface.
• the method is based on electrostatic attraction between oppositely charged polyelectrolytes for building the desired multilayers. By treating the fibers in consecutive steps with a solution containing polyions of opposite charge and permit these spontaneously to adsorb to the particle surface, multilayers of the stated kind are built up. In principle all types of polyelectrolytes may be used.
• ion-exchanging fibers where "membranes" with ion-exchanging properties are provided on the fiber surface, wet strength agents where the added polymers are reactive with the fibers and with each other, in order to provide permanent bonds between the fibers and for the production of highly swelling surface layers, where the added chemicals form swollen gel structures on the fiber surface for use in absorbent hygiene products.
• Another possible application are new types of fibers for printing paper, where the adsorbed polymers change colour when they are exerted to an electric, magnetic or electromagnetic field. Such polymers are available today.
• the fibers that are treated with the method according to the invention can be of optional kind, natural as well as synthetic fibers. Mainly cellulosic fiber are concerned. However it would be possible to treat synthetic fibers, for example for giving them a more hydrophilic surface.
• groups of fibers or particles can be treated according to the method.
• Anionic polyelectrolytes Anionic starch with different degrees of substitution, polystyrene sulphonate, carboxy methyl cellulose with different degrees of substitution, anionic galactoglucomannan, polyphosphoric acid, polymethacrylic acid, polyvinyl sulphate, alginate, copolymers of acryl amide and acrylic acid or 2-acrylic amide-2- alkylpropane sulphonic acid.
• Cationic polyelectrolyte Cationic galactoglucomannan, polyvinyl amine, polyvinyl pyridine and its N-alkyl derivatives, polyvinyl pyrrolidone, chitosan, alginate, modified polyacryl amides, polydiallyl dialkyl, cationic amide amines, condensation products between dicyane diamides, formaldehyde and an ammonium salt, reaction products between epichlorhydrine, polyepichlorhydrine and ammonia, primary and secondary amines, polymers formed by reaction between ditertiary amines or secondary amines or dihaloalkanes, polyethylene imines and polymers formed by polymerisation of N- (dialkylaminoalkyl)acrylic amide monomers.
• the example below shows the increase of tensile strength of sheets made in a dynamic sheet former.
• the pulp that is used was bleached SWK (softwood sulphate pulp) beaten in accordance with SCAN-C 18:65, diluted to 3g/l and pH adjusted to 8.
• PVAm polyvinyl amine
• CMC carboxy methyl cellulose
• an anionic polymer was added in excess, and after 10 minutes non-adsorbed polymer was removed through washing. Admixture of PVAm and CMC was repeated in several steps.
• fillers for papermaking have been used which have been treated through multilayer adsorption with the same polymers as in Example 1 above, i e polyvinyl amine and carboxy methyl cellulose.
• Paper sheets of 80 g/m 2 were made in a dynamic sheet former. The sheets were tested with respect to ash content, tensile strength index and opacity. The results are shown in Table 2 below.
• Ash content here means the content of filler treated as above and which has been added to the paper.
• Fig. 2 shows the effect on strength in the paper containing different amounts of filler particles treated according to the invention.
• Fig. 3 shows the effect on the opacity of paper when using different amounts of fillers treated according to Example 2 above.
• A-PAM anionic polyacryl amide
• DMDAAC cationic polydimethyl diallyl ammonium chloride

Landscapes

• Chemical & Material Sciences (AREA)
• Inorganic Chemistry (AREA)
• Life Sciences & Earth Sciences (AREA)
• Biochemistry (AREA)
• Paper (AREA)
• Paints Or Removers (AREA)
• Processes Of Treating Macromolecular Substances (AREA)
• Multicomponent Fibers (AREA)
• Nonwoven Fabrics (AREA)
• Treatments For Attaching Organic Compounds To Fibrous Goods (AREA)
• Chemical Or Physical Treatment Of Fibers (AREA)

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Cited By (7)

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Citations (7)

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• 1998
  • 1998-11-30 SE SE9804123A patent/SE521591C2/sv not_active IP Right Cessation
• 1999
  • 1999-11-23 BR BR9915750-0A patent/BR9915750A/pt not_active Application Discontinuation
  • 1999-11-23 ES ES99962630T patent/ES2259242T3/es not_active Expired - Lifetime
  • 1999-11-23 PL PL99348462A patent/PL348462A1/xx not_active Application Discontinuation
  • 1999-11-23 AT AT99962630T patent/ATE318289T1/de not_active IP Right Cessation
  • 1999-11-23 DE DE69930005T patent/DE69930005T2/de not_active Expired - Lifetime
  • 1999-11-23 EP EP99962630A patent/EP1137719B1/en not_active Expired - Lifetime
  • 1999-11-23 HU HU0104488A patent/HU225401B1/hu not_active IP Right Cessation
  • 1999-11-23 WO PCT/SE1999/002149 patent/WO2000032702A1/en active IP Right Grant
  • 1999-11-23 JP JP2000585336A patent/JP2002531714A/ja not_active Withdrawn
  • 1999-11-23 AU AU19035/00A patent/AU1903500A/en not_active Abandoned
  • 1999-11-30 CO CO99075241A patent/CO5121087A1/es unknown
• 2001
  • 2001-05-10 ZA ZA200103812A patent/ZA200103812B/en unknown
  • 2001-05-21 US US09/860,560 patent/US20020088579A1/en not_active Abandoned

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