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
  • D21H19/00—Coated paper; Coating material
  • D21H19/36—Coatings with pigments
  • D21H19/44—Coatings with pigments characterised by the other ingredients, e.g. the binder or dispersing agent
  • D21H19/54—Starch
• • 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
• • 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

Definitions

• This invention relates to a process for surface sizing or coating paper.
• the surface sizing of paper is a coating treatment which serves to make the surface of paper sufficiently smooth and strong, inter alia to improve the writing quality of the paper.
• the paper surface is provided with a layer of pigment, which serves inter alia to obtain a glossy and well printable surface.
• amylopectin starch types types of starch that do not contain amylose, the so-called amylopectin starch types.
• starch esters or starch ethers which exhibit a lesser tendency to retrograde owing to the introduction of substituents into the amylose molecules.
• additives which increase the viscostability of the starch solutions.
• appropriately modifying starch is laborious, while the addition of additives results in starch solutions having a more complex composition.
• the reagents used for etherifying or esterifying starch, the by-products formed in the process and/or the additives used may be undesirable with respect to toxicity and the environment.
• a first object of the invention is to provide a process as described in the preamble, in which an aqueous size or coating liquid is used which possesses a reduced and stable viscosity, so that that liquid can be used readily and reliably for a long time.
• Another object of the invention is to provide such a process which yields a surface size layer or coating layer with a good film strength and binding force.
• Yet another object of the invention is to provide a process for surface sizing paper, in which an aqueous size liquid is used in such a manner that an increase of the starch retention is effected or that, given the same starch retention, greater ease of handling and processability of the size liquid are achieved.
• Still another object of the invention is to provide a process for coating paper, in which an aqueous coating liquid is used which also contains a high concentration of pigment particles in suspension, that coating liquid possessing an improved rheology.
• the object of the invention is also to provide a process for preparing a converted (reduced viscosity) starch solution which is suitable for surface sizing or coating paper.
• an aqueous size or coating liquid which contains converted starch which has been obtained by treating gelatinized starch or a gelatinized modified starch in aqueous medium with a starch-converting enzyme selected from the group of the cyclodextrin glycosyl transferases (EC 2.4.1.19) and the branching enzymes (EC 2.4.1.18).
• a starch-converting enzyme selected from the group of the cyclodextrin glycosyl transferases (EC 2.4.1.19) and the branching enzymes (EC 2.4.1.18).
• Cyclodextrin glycosyl transferases (EC 2.4.1.19), CGT enzyme for short, are enzymes which via an exomechanism are capable of splitting off ring-shaped cyclodextrin molecules (having 6, 7 or 8 glucose units) from starch molecules.
• Branching enzymes (EC 2.4.1.18) are enzymes capable of converting ⁇ -1,4-glycosidic bonds in starch molecules to an ⁇ -1,6-bond.
• CGT enzyme and branching enzyme belong to the starch-converting enzymes, whereby during the conversion the reducing capacity of the starch product is not increased or is increased only to a very minor extent.
• all native (unmodified) starch types can be used, such as potato starch (which may contain 20 to 100 % by weight amylopectin), maize starch, wheat starch, tapioca starch or waxy maize starch. With particular advantage amylose-containing starches are used. Also usable as starting material are modified starches, such as starch esters, starch ethers, including cationic starch, and cross-linked starch.
• the employed cyclodextrin glycosyl transferase (EC 2.4.1.19) can originate from different sources, such as described in the following publications: R.L. Whistler, J.N. Bemiller, E.F. Paschall (Eds) Starch: Chemistry and Technology, Second Edition, 1984, Academic Press, pp. 143-144; D. Duchêne (Ed), Minutes of the Fifth International Symposium on Cyclodextrins, Editions de Santé, Paris 1990, pp. 19-61; and A.R. Hedges (Ed), Minutes of the Sixth International Symposium on Cyclodextrins, Editions de Santé, Paris 1992, pp. 23-58.
• European patent specification 0,418,945 describes processes for obtaining branching enzymes (EC 2.4.1.18).
• the starch For an effective action of the CGT-enzyme or the branching enzyme on the starch molecules, the starch must be in gelatinized condition.
• the gelatinization of the starch can be carried out batchwise or continuously in a steam injection device (jet-cookers).
• the enzyme can be added before or after the gelatinization.
• the starch, in the form of a suspension, wet cake or dry product is first mixed in the desired ratio with the enzyme preparation and, if necessary, dried.
• the dried mixed product (compound) can then be mixed with water in the paper factory, whereafter the starch is gelatinized and the conversion is carried out to obtain a converted starch solution for use in surface sizing or coating paper in accordance with the invention.
• the conversion conditions can vary within wide limits and depend in particular on the starting material, the enzyme, the origin of the enzyme and the desired extent of conversion. Suitable conditions are mentioned in the patent specifications mentioned hereinbefore.
• the enzyme used can be inactivated, for instance by increasing the temperature of the conversion mass.
• the converted starch solution obtained can be diluted with water to the desired processing concentration for surface sizing or coating paper. (SW49).
• Oxidized starch A obtained by oxidation of potato starch with sodium hypochlorite (low viscosity)
• Oxidized starch B obtained by oxidation of potato starch with sodium hypochlorite (medium to low viscosity)
• Oxidized starch C obtained by oxidation of potato starch with sodium hypochlorite (high viscosity)
• Hydroxyethyl starch A obtained by reacting oxidized potato starch (low viscosity) with ethylene oxide to an MS (molar substitution) of 0.07.
• Hydroxyethyl starch B obtained by reacting oxidized potato starch (medium viscosity) with ethylene oxide to an MS of 0.11.
• Hydroxyethyl starch C obtained by reacting oxidized potato starch (medium viscosity) with ethylene oxide to an MS of 0.07.
• ⁇ -amylase enzyme preparation Novoban 240.
• CGT-enzyme cyclodextrin glycosyl transferase (EC 2.4.1.19)
• Branching enzyme (EC 2.4.1.18) enzyme preparation obtained according to European patent specification 0,418,945.
• the degree of branching of a starch product was determined by measuring the DE (Dextrose Equivalent) of the starch product after debranching with the enzyme iso-amylase. The higher the DE (after debranching), the higher the degree of branching.
• potato starch gives a DE of 5.
• the additional branching effected by the branching enzyme according to the invention is calculated as:
• the additionally branched starch was prepared by treating an aqueous solution of potato starch with a branching enzyme preparation. This treatment took place at 50°C for 16 hours. The reaction was discontinued by heating to 100°C. Then the starch solution was purified by means of filtration. The filtrate was then sprayed-dried to a dry additionally branched starch product.
• the viscosity of the starch solutions was determined with a Brookfield viscosimeter, type LVT.
• the properties of the surface-sized paper and the coated paper were determined with the following test methods.
• PAPER TEST APPARATUS/MATERIALS TEST METHODS Brightness Elropho 2000 NEN 1843 Whiteness datacolor Tappi 452 Gloss Novo Gloss Tappi 480 Porosity Bekk, type 131 ED NEN 2014 Porosity Gurley, L & W type 6/2 NEN 2016 Smoothness Bekk, type 131 ED Tappi 479 Bursting strength Lorentzen & Wettre type 14-1 NEN 1765 Stiffness Kodak Pathé Adamel Lhomargy type RM-01 NEN 1840 IGT pick resistance IGT AIC 2-5 NEN 3095 Tappi 514 Dry pick fürbau printability tester type MZ-1 Standard Avebe Wet rub test Adams Spectronic 20 Bausch & Lomb Avebe-report 83171-330033 K & N ink penetration Lorilleus inkt Elrepho 2000 datacolor IGT W 25 CMT-30 Grüneweald Flu
• the CGT-enzyme converted starch solutions were produced as follows. To a suspension of starch in water (30% by weight of starch) was added 0.5% by weight (based on dry substance) of a CGT-enzyme preparation. This suspension was heated with direct steam (3°C per minute) to 75°C, whereafter the starch solution obtained was maintained at 75°C for 10 minutes. The converted starch solution obtained was then passed through a steam injection device (jet-cooker), where the CGT-enzyme was inactivated at 140°C for 45 seconds. The starch solution obtained was then diluted with water to approximately 20% by weight of dry substance and cooled to 50°C. The viscostability of these starch solutions was determined by measuring the viscosities (Brookfield, type LVT, 30 rpm) directly upon the preparation of the solution and subsequently after 1, 2, 4 and 24 hours' storage in an oven.
• the ⁇ -amylase converted starch solutions were produced as follows. To a suspension of starch in water (30% by weight starch) was added 0.025% by weight (based on dry substance) of an ⁇ -amylase preparation. This suspension was heated with direct steam (3°C per minute) to 75°C. Then the converted starch solution obtained was passed through a jet-cooker, where the enzyme was inactivated at 140°C for 45 seconds. The further treatment was the same as described above for the starch solutions converted with CGT-enzyme.
• oxidized starch prepared as follows. A suspension of oxidized starch (potato starch, maize starch) in water (35% by weight dry substance) was passed through a jet-cooker at 110°C (potato starch) or 140°C (maize starch). The thus obtained solution of oxidized starch was then diluted with water to approximately 20% by weight of dry substance and cooled to 50°C. The viscostability was measured as mentioned for the CGT-enzyme converted starch solution.
• Table 1 For potato starch and in Table 2 for maize starch.
• starch products were applied to a base paper (fluting from paper factory De Hoop) in the form of an aqueous solution by means of a horizontal size press (type T.H. Dixon; model 160-B; roll hardness 80 shore).
• the surface-sized paper was then dried with an air foil drier to a moisture content of 5% by weight.
• Table 3 shows the starch concentration (% by weight) and the Brookfield viscosity of the starch solutions to be applied to the base paper. Table 3 further specifies a number of relevant properties of the dried surface-sized paper obtained.
• Example 5 three CGT-enzyme converted potato starch products (produced as described in Example 1) of different viscosity levels are compared with three types of hydroxyethyl starch (with corresponding viscosity levels) as binding agent in paper coating. Table 5 specifies the viscosity of the coating binders.
• Table 6 specifies the basic formulation which is used to prepare the coating composition.
• Table 6 Coating composition Component Parts by weight CPS-clay 100 Starch product (see table 5) 6 Dow 935 (Dow Chemical) 6 Blancophor P (BASF) 0.3 BIP BC 336 (BIP) (hardener) 1 Dispex N40 (Allied Colloids) 0.3 Water to 54-58 wt.% dry substance
• Table 7 specifies the properties of the coating composition to be applied to paper (at 25-26°C and a pH of 8.0).
• Table 7 Properties of coating composition Starch product Viscosity 100 rpm mPa.s Hi-shear Viscosity 1100 rpm mPa.s Dry substance % by weight a) CGT-converted potato starch 800 52 57.30 b) CGT-converted potato starch 1240 87 56.14 c) CGT-converted potato starch 1560 95 54.30 d) Hydroxyethyl starch A 790 57 57.45 e) Hydroxyethyl starch B 1200 94 56.39 f) Hydroxyethyl starch C 1480 113 54.72
• This coating composition was applied to a fine-grade coating base paper (80 g/m2; manufacturer Nymölla), using a puddle type blade (Jagenberg; 50 m/min.) of the Dixon (approximately 15 g/m2).
• the coated paper was dried to 5% by weight of moisture by means of an air foil dryer on the Dixon.
• the coated papers were calendered by means of a laboratory calender at 50°C, 50 kg pressure and 2 nips.
• the paper samples obtained were conditioned and tested at 23°C and 50% relative humidity.
• the properties of the coated papers are specified in Table 8.
• Table 9 is a qualitative presentation of a number of test results of the coated paper.
• the coating composition contained 100 parts by weight of SPS-clay, 12.5 parts by weight of starch product and water.
• Table 10 shows the properties of the coating composition. Table 10 Properties coating composition Properties Additionally branched potato starch Oxidized potato starch Dry substance % 70.3 69.1 Water retention gr 0.5/1.5 kg/cm2 5/5 5/20 Brookfield 100 rpm, mPa.s 1160 1520 Hi-shear, 1100 rpm, mPa.s 332 247 Brookfield after 24 h. mPa.s 1040 1880
• the coating composition was applied to a fine-grade coating base paper (80g/m2; manufacturer Nymölla), using a puddle type blade (Jagenberg; speed 50 m/min.) of the Dixon (approximately 10 g/m2).
• the coated paper was dried to 5% by weight of moisture.
• the paper samples were conditioned and tested at 23°C and 50% relative humidity.
• the properties of the coated papers are shown in Table 11.
• Table 11 Properties of coated papers Properties Additionally branched potato starch Oxidized potato starch Whiteness % 108.1 107.6 Smoothness sec/10 ml 27.4 26.6 Porosity 3.1 2.6 IGT-pick VVP 960 1010 fürbau pick >3 >3

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• Paints Or Removers (AREA)
• Adhesives Or Adhesive Processes (AREA)

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• 1994
  • 1994-06-29 NL NL9401090A patent/NL9401090A/nl not_active Application Discontinuation
• 1995
  • 1995-06-27 DE DE69518702T patent/DE69518702T3/de not_active Expired - Fee Related
  • 1995-06-27 ES ES95201751T patent/ES2151575T5/es not_active Expired - Lifetime
  • 1995-06-27 EP EP95201751A patent/EP0690170B2/de not_active Expired - Lifetime
  • 1995-06-27 AT AT95201751T patent/ATE196172T1/de not_active IP Right Cessation
  • 1995-06-27 DK DK95201751T patent/DK0690170T4/da active

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