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
  • D21H17/21—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

Definitions

• This invention relates to a method for manufacturing paper, which comprises adding a cationic amylopectin potato starch, optionally in addition to other additives, to an aqueous suspension of cellulose fibers and then forming paper from this suspension in the conventional manner.
• a fibrous pulp By grinding raw materials used for paper-making, a fibrous pulp is obtained, in which the fibers are in a condition suitable for the paper formation.
• additives can be added to this fibrous pulp, such as resin glue, synthetic sizing agents, pigments and fillers (clay, titanium dioxide, talc, calcium carbonate, calcium sulphate), alum, retention agents and colloidal binders.
• the pulp mass is fed to a paper machine, where the paper formation takes place.
• the added additives serve inter alia to impart greater strength to the paper and to improve its writing and/or printing properties.
• colloidal binder in paper-making is cationic starch.
• cationic starch in paper-making is described in U.S. Patent 2,935,436.
• the use of cationic starch provides a number of advantages over the use of non-cationic starch. Mentioned as advantages are: increased retention of starch, fillers and pigments; increased paper strength (bursting strength, breaking strength, folding strength and picking resistance) and lower dosage.
• starch consist of granules in which two types of glucose polymers occur, viz. amylose (15-35% by weight on dry substance) and amylopectin (65-85% by weight on dry substance).
• Amylose consists of non-branched or little branched molecules having an average degree of polymerization of 1,000 to 5,000 (depending on the kind of starch).
• Amylopectin consists of very large, highly branched molecules having an average degree of polymerization of about 2,000,000.
• the commercially most important types of starch viz. maize starch, potato starch, wheat starch and tapioca starch, contain 15-30% by weight of amylose.
• starch granules consist substantially completely of amylopectin. Calculated as a percentage by weight of the dry substance, these starch granules contain more than 95% and usually more than 98% of amylopectin. The amylose content of these cereal starch granules is therefore less than 5% and usually less than 2%. It has been found that during the formation of amylopectin cereal starch granules in the grain plant, the enzyme that catalyzes the synthesis of amylose molecules is absent.
• the above cereal varieties are sometimes designated as waxy cereal grains and the amylopectin starch granules isolated therefrom as waxy cereal starches.
• amylopectin content of at least 85% in paper-making.
• the required amylopectin content can be achieved by fractionating an amylose-containing starch.
• a cereal variety is used that already has a very high amylopectin content by nature, such as waxy maize starch, which contains 99-100% amylopectin.
• amylopectin potato starch is herein understood to mean the potato starch granules, isolated from potato tubers, having an amylopectin content of at least 95% by weight, calculated on the dry substance.
• amylopectin potato starch differs from those of the waxy cereal starches.
• amylopectin potato starch has a much lower content of lipids and proteins than the waxy cereal starches.
• Problems regarding odour and foam formation which may arise on account of the lipids and proteins when using waxy cereal starch products (native and modified), do not arise or do so to a much lesser extent when corresponding amylopectin potato starch products are used.
• amylopectin potato starch contains chemically bound phosphate groups. As a result, in dissolved condition amylopectin potato starch products have a specific polyelectrolyte character.
• cationic amylopectin potato starch is eminently suitable for use as colloidal binder in paper-making. With regard to drainage, retention and paper strength, cationic amylopectin potato starch gives equivalent or better results compared with corresponding cationic derivatives of other starch raw materials.
• the invention accordingly relates to a method for the manufacture of paper, which comprises adding to an aqueous suspension of cellulose fibers a water-soluble or dissolved cationic amylopectin potato starch, optionally in addition to other additives, and then forming paper from this suspension in conventional manner.
• cationic starch Methods for manufacturing cationic starch have been described by D.B. Solarek: Cationic Starches, in the book of O.B. Wurzburg (Ed.): Modified Starches: Properties and Uses, CRC Press Inc., Boca Raton, Florida, 1986, pp. 113-130.
• the methods described therein can also be used for the preparation of cationic amylopectin potato starch.
• the amylopectin potato starch may be additionally modified physically, chemically and/or enzymatically.
• the invention also embraces the use of these additionally modified amylopectin potato starch products.
• the degree of substitution (DS) of the cationic amylopectin potato starch to be used according to the invention is preferably between 0.005 and 0.5 and more preferably between 0.01 and 0.2.
• the amount of cationic amylopectin potato starch which according to the invention is included in the paper pulp depends inter alia on the kind of pulp used, the working conditions used and the desired paper properties. Preferably, 0.05 to 10% by weight and more preferably 0.1 to 2% by weight of starch derivative (dry substance) calculated on the paper pulp (dry substance) is used.
• the cationic amylopectin potato starch to be used according to the invention is preferably first gelatinized in water, whereafter the resultant starch solution (optionally after dilution) is added to the pulp mass. It is also possible, however, to mix pre-gelatinized cold-soluble cationic amylopectin potato starch (as dry product or after dissolution in water) with the pulp mass.
• the cationic amylopectin potato starch can be added at any point in the paper-making process.
• the cationic starch product can therefore be added to the pulp while it is disposed in the head box, the Hollander, the hydropulper or the dusting box.
• an anionic amylopectin potato starch can also be added to the pulp. (SW 50).
• the cationic starch products were slurried in water, forming a starch suspension with 10% by weight of starch. This suspension was gelatinized with steam. The obtained starch solution was diluted with water to 1% by weight dry substance.
• the test pulp was prepared by mixing a diluted fiber suspension (containing 100% bleached birch sulphate on dry substance), with 20% by weight (calculated on dry cellulose fiber) of calcium carbonate (filler) and diluted starch solution. The amount of added cationic starch was 1.25% by weight (dry substance) calculated on the dry fiber. The consistency of the tested pulp was 0.4%.
• the test pulps were made into handsheets with a FRET sheetformer. The handsheets were dried in vacuum dryers to a moisture content of 7% by weight.
• the properties of the formed paper were determined with the following test methods: Paper test Apparatus/materials Test method Sheet weight Balance NEN 1109 Bursting strength Lorentzen & Wettre type 14-1 Burstomatic NEN 1765 Tappi T403 -om-85 Tensile strength Adamel Lhomargy type DY-20 NEN 1249 Tappi T494 -om-88 Internal Bond Schröder-Werkstoff fürmaschinen type SN.22.91.1007 Tappi T506 -wd-83 UM 584 Starch content Spectrophotometer Hexokinase method according to Boehringer The test results are recorded in Table 1.
• the cationic amylopectin starch gave equivalent or higher strength values in the paper test sheets, as compared to the other cationic starch products.
• the pulp used comprised an aqueous slurry of 70% by weight (on dry substance) of short fiber and 30% by weight of long fiber. Calcium carbonate (20% by weight on dry pulp) was added to the stock. The pulp was beaten with a consistency of 1.8% in a Pilao refiner to 27°SR. The pulp was diluted with water containing 100 ppm CaCl2 and 150 ppm NaHCO3.
• the cationic amylopectin potato starch was slurried in water (10% dry substance) and cooked with steam (25 minutes; 850 rpm).
• the starch solution was added in quantities of 0.75%, 0.875% and 1.0% by weight of dry starch calculated on dry fiber.
• the pulp was further diluted with white water.
• the obtained starch solution was diluted with water to 1% by weight dry substance.
• the pulp consisted of 80% by weight bleached birch sulphate and 20% by weight calcium carbonate as a filler (both calculated on consistency). The pulp had a consistency of 0.6%.
• the sheets were made with a FRET sheetformer, obtained from the CTP in Grenoble.
• the amount of starch added to the pulp was 0.55% and 0.65% by weight, calculated as dry substance on consistency. Before dewatering, the pulp with the added starch was diluted to 0.3%.
• the handsheets were dried in vacuum dryers to a moisture content of approximately 4% by weight.
• the obtained paper was tested according to the above-mentioned test methods, after being conditioned to a temperature of 23°C and a relative humidity of 50%.
• the results of the tests are collected in the following Tables 3 (0.55% added starch) and 4 (0.65% added starch).

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• Paper (AREA)
• Diaphragms For Electromechanical Transducers (AREA)
• Pens And Brushes (AREA)

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Cited By (8)

Citations (3)

• 1994
  • 1994-09-13 NL NL9401487A patent/NL9401487A/nl not_active Application Discontinuation
• 1995
  • 1995-09-12 DK DK95202472T patent/DK0703314T3/da active
  • 1995-09-12 AT AT95202472T patent/ATE180296T1/de not_active IP Right Cessation
  • 1995-09-12 DE DE69509722T patent/DE69509722T2/de not_active Revoked
  • 1995-09-12 ES ES95202472T patent/ES2133659T3/es not_active Expired - Lifetime
  • 1995-09-12 EP EP95202472A patent/EP0703314B1/de not_active Revoked
  • 1995-09-13 FI FI954282A patent/FI954282L/fi not_active Application Discontinuation

Patent Citations (3)

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