EP0013969B1 - Process for producing a paper having a high dry-strength and a low wet-strength - Google Patents

Process for producing a paper having a high dry-strength and a low wet-strength Download PDF

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Publication number
EP0013969B1
EP0013969B1 EP80100302A EP80100302A EP0013969B1 EP 0013969 B1 EP0013969 B1 EP 0013969B1 EP 80100302 A EP80100302 A EP 80100302A EP 80100302 A EP80100302 A EP 80100302A EP 0013969 B1 EP0013969 B1 EP 0013969B1
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EP
European Patent Office
Prior art keywords
paper
weight
strength
acrylic acid
polymer
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EP80100302A
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German (de)
French (fr)
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EP0013969A1 (en
Inventor
Juergen Dr. Hartmann
Joachim Dr. Stedefeder
Walter Denzinger
Sigberg Dr. Pfohl
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BASF SE
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BASF SE
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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
    • D21H17/41—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
    • D21H17/43—Carboxyl groups or derivatives thereof
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/31504—Composite [nonstructural laminate]
    • Y10T428/31855—Of addition polymer from unsaturated monomers
    • Y10T428/3188—Next to cellulosic
    • Y10T428/31895—Paper or wood
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/31504—Composite [nonstructural laminate]
    • Y10T428/31855—Of addition polymer from unsaturated monomers
    • Y10T428/3188—Next to cellulosic
    • Y10T428/31895—Paper or wood
    • Y10T428/31906—Ester, halide or nitrile of addition polymer

Definitions

  • FR-A-931 044 it is known to improve the mechanical strength of paper by impregnating paper with an aqueous solution of a polymer containing acid groups.
  • the free polycarboxylic acids e.g. Polymethacrylic acid or the alkali or ammonium salts of the polycarboxylic acids.
  • the invention has for its object to further improve the mechanical properties of paper, in particular to provide a method for producing paper with high dry strength and low wet strength.
  • the viscosity of the polymer salts in a 2 % strength aqueous solution is 5 to 100 mPas (Brookfield viscometer, 20 revolutions / minute) at a temperature of 20 ° C.
  • the homopolymers and copolymers are prepared by known processes by polymerizing the monomers, cf. US-A 2 819 189 and US-A 2 999 038.
  • the monomers or mixtures thereof are polymerized continuously or discontinuously with the aid of radical polymerization initiators, preferably in water. If the alkali metal or alkaline earth metal salts of acrylic acid or methacrylic acid are already used in the polymerization of the monomers, the copolymer salt solutions to be used according to the invention are obtained directly.
  • Acrylic acid and / or methacrylic acid can be polymerized with the corresponding amides or nitriles in water in the manner of a precipitation polymerization.
  • the resulting copolymers can be neutralized directly with alkali or alkaline earth metal hydroxides.
  • the homopolymers or copolymers obtained in the precipitation polymerization in water can be isolated, dried and mixed with one or more dry, powdered alkaline earth metal hydroxides or oxides. These powdery mixtures can then be easily dissolved in water to give a clear solution.
  • the calcium and magnesium salts of the copolymers mentioned above are of particular importance.
  • the polymers contain 91 to 100, preferably 95 to 100% by weight of acrylic acid and / or methacrylic acid and 0 to 9, preferably up to 5% by weight of acrylonitrile, methacrylonitrile, acrylamide or methacrylamide, vinyl acetate, maleic anhydride, diisobutene and optionally acrylic ester or methacrylic acid ester.
  • the esters are preferably derived from monohydric, primary alcohols having 1 to 4 carbon atoms.
  • the calcium and magnesium salts of homopolymers of acrylic acid and methacrylic acid are of particular importance for the process according to the invention.
  • Calcium and magnesium salts and, if appropriate, mixtures of alkaline earth and alkali salts of homopolymers of acrylic acid or methacrylic acid and copolymers of acrylic acid and acrylamide, acrylic acid and acrylonitrile, acrylic acid, methacrylic acid and acrylamide, and copolymers of acrylic acid, acrylamide and methacrylamide are preferably used. At least 30% of the carboxyl groups in the polymers are neutralized with alkaline earth metal ions. The degree of neutralization is generally 70 to 100%.
  • the mixing ratio of the alkaline earth to alkali salts is preferably 30 to 50 to 70 to 50.
  • a 2% aqueous solution of the alkali metal or alkaline earth metal salts to be used according to the invention has a viscosity (Brookfield 20 / min) of 5 to 100, preferably 10 to, at a temperature of 20 ° C. 30 mPas.
  • the pH of the copolymer salt solution is in the range between 4.0 and 10.0.
  • the water-soluble alkaline earth metal salts of the polymers in question are applied to the paper in the form of a 1 to 10% strength aqueous solution.
  • the paper can be impregnated with the alkaline earth metal salt solution of the copolymers, e.g. in a size press, or spray a solution of the copolymer salt onto the paper.
  • the absorption of preparation solution depends on the absorbency of the paper used. In relation to the solids, to achieve a good increase in dry strength of the paper, it is sufficient to impregnate the paper with 1 to 4% by weight of the alkaline earth metal salts of the polymers described.
  • the increase in the strength of the paper is immediately after drying the paper under usual conditions, e.g. Temperatures of 80 to 110 ° C, obtained. It is not necessary to age the impregnated paper. Also of particular advantage is the fact that it is possible to use the alkaline earth metal salts of the polymers to be used according to the invention together with the starch solutions frequently used in practice, the preparation solutions being 2 to 10% by weight, preferably 2 to 6% by weight. Starch and 1 to 3% by weight of the alkaline earth metal salts of polymers to be used according to the invention.
  • All known paper qualities e.g. Writing, printing and packaging papers are impregnated with the products to be used according to the invention.
  • the papers can be made from a variety of fiber materials such as sulfite or sulfate pulp (bleached or unbleached), wood pulp or waste paper.
  • the use of the alkaline earth metal salts of polymers of acrylic acid and / or methacrylic acid and the comonomers mentioned under b) as surface application agents for paper leads to an unexpected increase in the dry strength of the paper without the wet strength of the paper being appreciably increased.
  • the dry strength properties of the paper which are noticeably improved, are e.g. the tear length, burst pressure, pick resistance, tear resistance and the CMT value.
  • the invention is illustrated by the following examples.
  • the parts given in the examples are parts by weight, the percentages relate to the weight.
  • the viscosities stated were measured at a temperature of 20 ° C. in a Brookfield viscometer at 20 revolutions / minute.
  • the dry tear length was determined in accordance with DIN 53 112, sheet 1 and the wet tear length in accordance with DIN 53 112, sheet 2.
  • the pick resistance of the paper was determined according to the Dennison wax test.
  • a homopolymer of acrylic acid which was obtained by polymerizing acrylic acid in aqueous solution using potassium peroxide disulfate as a catalyst, is neutralized with magnesium hydroxide.
  • a 2% strength aqueous solution of the magnesium salt of the homopolymer is prepared which has a pH of 5.0.
  • a wood-free, unsized offset paper produced on a paper machine with a freeness of 25 ° SR, 14% ash (kaolin) and 2% alum and a weight of 80 g / m 2 is mixed with a 2% aqueous solution of the above-mentioned magnesium salt of the homopolymer impregnated with acrylic acid and then dried at a temperature of 100 ° C.
  • Table 1 shows the viscosity of the preparation solution, the amount of pure polymer salt applied to the paper, based on the weight of the paper, and some properties of the paper obtained.
  • Example 1 The homopolymer of acrylic acid described in Example 1 is neutralized with ammonia instead of magnesium oxide and used as a 2% solution at a pH of 5.0 as an impregnating agent for the offset paper specified in Example 1 (Table 1).
  • Example 1 The homopolymer of acrylic acid described in Example 1 is used in non-neutralized form as a 2% aqueous solution at a pH of 2.5 as an impregnating agent for the offset paper specified in Example 1.
  • Table 1 shows the properties of the paper obtained together with those properties of the paper which were measured after treating the paper with water and drying (comparative example 1c).
  • a 2% solution of this Copolymers are applied to a wood-free, unsized offset paper with 1% alum, a freeness of 25 ° SR, 10% ash (kaolin) and a weight of 80 g / m 2 .
  • the impregnated paper is dried at a temperature of 100 ° C. Further information on the preparation solution and the properties of the impregnated paper can be found in Table 2.
  • the copolymer of 95% acrylic acid and 5% acrylamide described in Example 2 is neutralized with ammonia instead of calcium hydroxide and used as a 2% aqueous solution at a pH of 6.0 as an impregnating agent for the offset paper specified in Example 2 (Table 2 ).
  • Example 2 The copolymer of 95% acrylic acid and 5% acrylamide specified in Example 2 is used without neutralization in the form of a 2% strength aqueous solution which has a pH of 2.5 for impregnating paper, which is described in Example 2.
  • the paper was dried at the same temperature as in Example 2.
  • the results are shown in Table 2.
  • Table 2 For comparison, the values are also given in Table 2, which are obtained when the paper described in Example 2 is impregnated with water and dried at 100.degree.
  • the examples and comparative examples show that the polymer salts to be used according to the invention compared to the corresponding ammonium salts or the polyacids lead to a further increase in the dry strength of the paper without undesirably increasing the wet strength of the paper.

Abstract

A process for the manufacture of paper having a high dry strength and a low wet strength, by treating the surface of the paper with an aqueous solution of an alkali metal and/or alkaline earth metal salt of a polymer of (a) from 91 to 100% by weight of acrylic acid and/or methacrylic acid and (b) from 0 to 9% by weight of acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, vinyl acetate, maleic anhydride, diisobutylene, an ester of acrylic acid and/or an ester of methacrylic acid, which has a viscosity of from 5 to 100 mPas in 2% strength aqueous solution at 20 DEG C., and drying the impregnated paper. The polymer is generally employed in an amount of from 1 to 4% by weight, based on dry paper, and increases the dry strength of the paper without substantially increasing the wet strength.

Description

In der DE-C 27 41 753 wird ein Verfahren zur Herstellung von Papier mit hoher Trockenfestigkeit und niedriger Naßfestigkeit durch Behandeln der Oberfläche des Papiers mit wasserlöslichen Salzen von Polymerisaten auf Basis äthylenisch ungesättigter Carbonsäuren vorgeschlagen, das dadurch gekennzeichnet ist, daß als Salze von Polymerisaten wasserlösliche Alkali- und/oder Erdalkylisalze von CopolymerIsaten aus

  • a) 90 bis 30 Gew.% Acrylsäure und/oder Methacrylsäure,
  • b) 10 bis 70 Gew.% Acrylnitril, Methacrylnitril, Acrilamid und/oder Methacrylamid sowie ggf.
  • c) bis zu 30 Gew.% eines Acrylsäure- oder Methacrylsäureesters,

die in 2 %iger wäßriger Lösung bei einer Temperatur von 20 °C eine Viskosität von 5 bis 100 mPas (Brookfield-Viskosimeter, 20 Umdrehungen/Minute) haben, verwendet werden.DE-C 27 41 753 proposes a process for the production of paper with high dry strength and low wet strength by treating the surface of the paper with water-soluble salts of polymers based on ethylenically unsaturated carboxylic acids, which is characterized in that water-soluble salts of polymers Alkali and / or earth alkyl salts of copolymerizates
  • a) 90 to 30% by weight of acrylic acid and / or methacrylic acid,
  • b) 10 to 70% by weight of acrylonitrile, methacrylonitrile, acrilamide and / or methacrylamide and, if appropriate
  • c) up to 30% by weight of an acrylic or methacrylic ester,

which have a viscosity of 5 to 100 mPas (Brookfield viscometer, 20 revolutions / minute) in a 2% strength aqueous solution at a temperature of 20 ° C.

Aus der FR-A-931 044 ist bekannt, die mechanische Festigkeit von Papier durch Imprägnieren von Papier mit einer wäßrigen Lösung eines Säuregruppen enthaltenden Polymeren zu verbessern. Man verwendet die freien Polycarbonsäuren, z.B. Polymethacrylsäure oder die Alkali- oder Ammoniumsalze der Polycarbonsäuren.From FR-A-931 044 it is known to improve the mechanical strength of paper by impregnating paper with an aqueous solution of a polymer containing acid groups. The free polycarboxylic acids, e.g. Polymethacrylic acid or the alkali or ammonium salts of the polycarboxylic acids.

Der Erfindung liegt die Aufgabe zugrunde, die mechanischen Eigenschaften von Papier weiter zu verbessern, insbesondere ein Verfahren zur Herstellung von Papier mit hoher Trockenfestigkeit und niedriger Naßfestigkeit zur Verfügung zu stellen.The invention has for its object to further improve the mechanical properties of paper, in particular to provide a method for producing paper with high dry strength and low wet strength.

; Die Aufgabe wird erfindungsgemäß dadurch gelöst, daß wasserlösliche Erdalkalisalze von Polymerisaten aus

  • a) 91 bis 100 Gew.% Acrylsäure und/oder Methacrylsäure und
  • b) 0 bis 9 Gew.% Acrylnitril, Methacrylnitril, Acrylamid, Methacrylamid, Vinylacetat, Maleinsäureanhydrid, Diisobuten, Acrylsäure- und/oder Methacrylsäureester

verwendet werden.; The object is achieved in that water-soluble alkaline earth metal salts from polymers
  • a) 91 to 100 wt.% Acrylic acid and / or methacrylic acid and
  • b) 0 to 9% by weight of acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, vinyl acetate, maleic anhydride, diisobutene, acrylic acid and / or methacrylic acid ester

be used.

Die Viskosität der Polymerisatsalze beträgt in 2 %iger wäßriger Lösung bei einer Temperatur von 20 °C 5 bis 100 mPas (Brookfield-Viskosimeter, 20 Umdrehungen/Minute).The viscosity of the polymer salts in a 2 % strength aqueous solution is 5 to 100 mPas (Brookfield viscometer, 20 revolutions / minute) at a temperature of 20 ° C.

Die Homo- und Copolymerisate werden nach bekannten Verfahren durch Polymerisieren der Monomeren hergestellt, vgl. US-A 2 819 189 und US-A 2 999 038. Die Monomeren bzw. deren Mischungen werden dabei kontinuierlich oder diskontinuierlich mit Hilfe von radikalischen Polymerisationsinitiatoren, vorzugsweise in Wasser, polimerisiert. Wenn man bei der Polymerisation der Monomeren bereits die Alkali- bzw. Erdalkalisalze der Acrylsäure oder Methacrylsäure einsetzt, erhält man direkt die gemäß Erfindung zu verwendenden Copolymerisatsalz-Lösungen. Acrylsäure und/oder Methacrylsäure können mit den entsprechenden Amiden oder Nitrilen in Wasser nach Art einer Fällungspolymerisation polymerisiert werden. Die dabei anfallenden Copolymerisate können direkt mit Alkali- bzw. Erdalkalihydroxiden neutralisiert werden.The homopolymers and copolymers are prepared by known processes by polymerizing the monomers, cf. US-A 2 819 189 and US-A 2 999 038. The monomers or mixtures thereof are polymerized continuously or discontinuously with the aid of radical polymerization initiators, preferably in water. If the alkali metal or alkaline earth metal salts of acrylic acid or methacrylic acid are already used in the polymerization of the monomers, the copolymer salt solutions to be used according to the invention are obtained directly. Acrylic acid and / or methacrylic acid can be polymerized with the corresponding amides or nitriles in water in the manner of a precipitation polymerization. The resulting copolymers can be neutralized directly with alkali or alkaline earth metal hydroxides.

Es ist jedoch auch möglich, bei der Polymerisation zu 10 bis 40 % mit Ammonium-, Alkali- oder Erdalkaliionen neutralisierte Acrylsäure bzw. Methacrylsäure in wäßriger Lösung zu polymerisieren und die erhaltene wäßrige Polymerisatlösung anschließend mit Erdalkalisalzen vollständig zu neutralisieren. Ein Herstellverfahren für die Copolymerisate, bei dem teilweise mit Ammoniumionen neutralisierte Acrylsäure oder Methacrylsäure eingesetzt wird, ist aus der DE-B 20 04 676 bekannt. Die Polymerisate können auch nach dem Verfahren der umgekehrten Suspensionspolymerisation, das aus der DE-C 1 081 228 bekannt ist sowie nach dem inversen Emulsionspolymerisationsverfahren gemäß der DE-C 1 089173 hergestellt werden.However, it is also possible to polymerize in the polymerization to 10 to 40% neutralized with ammonium, alkali or alkaline earth ions acrylic acid or methacrylic acid in aqueous solution and then to completely neutralize the aqueous polymer solution obtained with alkaline earth metal salts. A preparation process for the copolymers, in which acrylic acid or methacrylic acid partially neutralized with ammonium ions is used, is known from DE-B 20 04 676. The polymers can also be prepared by the reverse suspension polymerization process known from DE-C 1 081 228 and by the inverse emulsion polymerization process according to DE-C 1 089173.

Man kann jedoch auch die bei der Fällungspolymerisation in Wasser erhaltenen Homo- oder Copolymerisate isolieren, trocknen und mit einem oder mehreren trockenen, pulverförmigen Erdalkalihydroxiden oder -oxiden mischen. Diese pulvrigen Mischungen können dann ohne Schwierigkeiten in Wasser gelöst werden, wobei man eine klare Lösung erhält.However, the homopolymers or copolymers obtained in the precipitation polymerization in water can be isolated, dried and mixed with one or more dry, powdered alkaline earth metal hydroxides or oxides. These powdery mixtures can then be easily dissolved in water to give a clear solution.

Besondere Bedeutung haben die Calcium- und Magnesiumsalze der oben genannten Copolymerisate. Die Polymerisate enthalten 91 bis 100, vorzugsweise 95 bis 100 Gew.% Acrylsäure und/oder Methacrylsäure sowie 0 bis 9, vorzugsweise bis zu 5 Gew.% Acrylnitril, Methacrylnitril, Acrylamid oder Methacrylamid, Vinylacetat, Maleinsäureanhydrid, Diisobuten sowie gegebenenfalls Acrylester oder Methacrylsäureester. Die Ester leiten sich vorzugsweise von einwertigen, primären Alkoholen mit 1 bis 4 Kohlenstoffatomen ab. Besondere Bedeutung für das erfindungsgemäße Verfahren haben die Calcium-und Magnesiumsalze von Homopolymerisaten der Acrylsäure und Methacrylsäure.The calcium and magnesium salts of the copolymers mentioned above are of particular importance. The polymers contain 91 to 100, preferably 95 to 100% by weight of acrylic acid and / or methacrylic acid and 0 to 9, preferably up to 5% by weight of acrylonitrile, methacrylonitrile, acrylamide or methacrylamide, vinyl acetate, maleic anhydride, diisobutene and optionally acrylic ester or methacrylic acid ester. The esters are preferably derived from monohydric, primary alcohols having 1 to 4 carbon atoms. The calcium and magnesium salts of homopolymers of acrylic acid and methacrylic acid are of particular importance for the process according to the invention.

Vorzugsweise verwendet man Calcium- und Magnesiumsalze sowie gegebenenfalls Mischungen von Erdalkali- und Alkalisalzen von Homopolymerisaten der Acrylsäure oder Methacrylsäure sowie Copolymerisate aus Acrylsäure und Acrylamid, Acrylsäure und Acrylnitril, Acrylsäure, Methacrylsäure und Acrylamid, und Copolymerisate aus Acrylsäure, Acrylamid und Methacrylamid. Die Carboxylgruppen der Polymerisate sind zu mindestens 30 % mit Erdalkaliionen neutralisiert. Der Neutralisationsgrad beträgt im allgemeinen 70 bis 100 %. Das Mischungsverhältnis der Erdalkali- zu Alkalisalzen beträgt vorzugsweise 30 bis 50 zu 70 bis 50.Calcium and magnesium salts and, if appropriate, mixtures of alkaline earth and alkali salts of homopolymers of acrylic acid or methacrylic acid and copolymers of acrylic acid and acrylamide, acrylic acid and acrylonitrile, acrylic acid, methacrylic acid and acrylamide, and copolymers of acrylic acid, acrylamide and methacrylamide are preferably used. At least 30% of the carboxyl groups in the polymers are neutralized with alkaline earth metal ions. The degree of neutralization is generally 70 to 100%. The mixing ratio of the alkaline earth to alkali salts is preferably 30 to 50 to 70 to 50.

Eine 2 %ige wäßrige Lösung der erfindungsgemäß zu verwendenden Alkali- bzw. Erdalkalisalze hat bei einer Temperatur von 20 °C eine Viskosität (Brookfield 20/min) von 5 bis 100, vorzugsweise 10 bis 30 mPas. Der pH-Wert der Copolymerisatsalz-Lösung liegt in dem Bereich zwischen 4,0 und 10,0.A 2% aqueous solution of the alkali metal or alkaline earth metal salts to be used according to the invention has a viscosity (Brookfield 20 / min) of 5 to 100, preferably 10 to, at a temperature of 20 ° C. 30 mPas. The pH of the copolymer salt solution is in the range between 4.0 and 10.0.

Die wasserlöslichen Erdalkalisalze der in Betracht kommenden Polymerisate werden in Form einer 1 bis 10 %igen wäßrigen Lösung auf das Papier aufgebracht. Man kann das Papier mit der Erdalkalisalzlösung der Copolymerisate imprägnieren, z.B. in einer Leimpresse, oder eine Lösung des Copolymerisatsalzes auf das Papier aufsprühen. Die Aufnahme an Präparationslösung ist von der Saugfähigkeit des eingesetzten Papiers abhängig. Bezogen auf die Feststoffe reicht es zur Erzielung einer guten Trockenfestigleitssteigerung des Papiers aus, das Papier mit 1 bis 4 Gew.% der beschriebenen Erdalkalisalze der Polymerisate zu imprägnieren.The water-soluble alkaline earth metal salts of the polymers in question are applied to the paper in the form of a 1 to 10% strength aqueous solution. The paper can be impregnated with the alkaline earth metal salt solution of the copolymers, e.g. in a size press, or spray a solution of the copolymer salt onto the paper. The absorption of preparation solution depends on the absorbency of the paper used. In relation to the solids, to achieve a good increase in dry strength of the paper, it is sufficient to impregnate the paper with 1 to 4% by weight of the alkaline earth metal salts of the polymers described.

Die Erhöhung der Festigkeit des Papiers wird direkt nach der Trocknung des Papiers unter üblichen Bedingungen, z.B. Temperaturen von 80 bis 110 °C, erhalten. Eine Alterung des imprägnierten Papiers ist nicht erforderlich. Von besonderem Vorteil ist auch die Tatsache, daß es möglich ist, die erfindungsgemäß zu verwendenden Erdalkalisalze der Polymerisate auch zusammen mit den häufig in der Praxis eingesetzten Stärkelösungen zu verwenden, wobei die Präparationslösungen 2 bis 10 Gew.%, vorzugsweise 2 bis 6 Gew.% Stärke und 1 bis 3 Gew.% der gemäß Erfindung einzusetzenden Erdalkalisalze von Polymerisaten enthalten.The increase in the strength of the paper is immediately after drying the paper under usual conditions, e.g. Temperatures of 80 to 110 ° C, obtained. It is not necessary to age the impregnated paper. Also of particular advantage is the fact that it is possible to use the alkaline earth metal salts of the polymers to be used according to the invention together with the starch solutions frequently used in practice, the preparation solutions being 2 to 10% by weight, preferably 2 to 6% by weight. Starch and 1 to 3% by weight of the alkaline earth metal salts of polymers to be used according to the invention.

Es können alle bekannten Papierqualitäten z.B. Schreib-, Druck- und Verpackungspapiere mit den erfindungsgemäß zu verwendenen Produkten imprägniert werden. Die Papiere können dabei aus einer Vielzahl von Fasermaterialien, wie Sulfit- oder Sulfat-Zellstoff (gebleicht oder ungebleicht), Holzschliff oder Altpapier hergestellt sein. Die Verwendung der Erdalkalisalze von Polymerisaten aus Acrylsäure und/oder Methacrylsäure und den unter b) genannten Comonomeren als Oberflächenauftragsmittel für Papier führt zu einer unerwarteten Erhöhung der Trockenfestigkeit des Papiers, ohne daß dabei die Naßfestigkeit des Papiers nennenswert erhöht wird. Bei den Trockenfestigkeitseigenschaften des Papiers, die merklich verbessert werden, handelt es sich z.B. um die Reißlänge, den Berstdruck, die Rupffestigkeit, Weiterreißfestigkeit und den CMT-Wert.All known paper qualities e.g. Writing, printing and packaging papers are impregnated with the products to be used according to the invention. The papers can be made from a variety of fiber materials such as sulfite or sulfate pulp (bleached or unbleached), wood pulp or waste paper. The use of the alkaline earth metal salts of polymers of acrylic acid and / or methacrylic acid and the comonomers mentioned under b) as surface application agents for paper leads to an unexpected increase in the dry strength of the paper without the wet strength of the paper being appreciably increased. The dry strength properties of the paper, which are noticeably improved, are e.g. the tear length, burst pressure, pick resistance, tear resistance and the CMT value.

Die Erfindung wird anhand der folgenden Beispiele näher erläutert. Die in den Beispielen angegebenen Teile sind Gewichtsteile, die Prozentangaben beziehen sich auf das Gewicht. Die angegebenen Viskositäten wurden bei einer Temperatur von 20 °C in einem Brookfield-Viskosimeter bei 20 Umdrehungen/Minute gemessen. Die Trockenreißlänge wurde gemäß DIN 53 112, Blatt 1 und die Naßreißlänge gemäß DIN 53 112, Blatt 2, bestimmt. Die Rupffestigkeit des Papiers wurde nach dem Dennison-Wachs-Test ermittelt.The invention is illustrated by the following examples. The parts given in the examples are parts by weight, the percentages relate to the weight. The viscosities stated were measured at a temperature of 20 ° C. in a Brookfield viscometer at 20 revolutions / minute. The dry tear length was determined in accordance with DIN 53 112, sheet 1 and the wet tear length in accordance with DIN 53 112, sheet 2. The pick resistance of the paper was determined according to the Dennison wax test.

Beispiel 1example 1

Ein Homopolymerisat der Acrylsäure, das durch Polymerisieren von Acrylsäure in wäßriger Lösung mit Hilfe von Kaliumperoxiddisulfat als Katalysator erhalten wurde, wird mit Magnesiumhydroxid neutralisiert. Es wird eine 2%ige wäßrige Lösung des Magnesiumsalzes des Homopolymerisates hergestellt, die einen pH-Wert von 5,0 aufweist.A homopolymer of acrylic acid, which was obtained by polymerizing acrylic acid in aqueous solution using potassium peroxide disulfate as a catalyst, is neutralized with magnesium hydroxide. A 2% strength aqueous solution of the magnesium salt of the homopolymer is prepared which has a pH of 5.0.

Ein auf einer Papiermaschine hergestelltes holzfreies, ungeleimtes Offsetpapier mit einem Mahlgrad von 25 °SR, 14 % Asche (Kaolin) und 2 % Alaun und einem Gewicht von 80 g/m2 wird mit einer 2 %igen wäßrigen Lösung des oben genannten Magnesiumsalzes des Homopolymerisates der Acrylsäure imprägniert und anschließend bei einer Temperatur von 100 °C getrocknet. In der Tabelle 1 sind die Viskosität der Präparationslösung, die auf das Papier aufgetragene Menge des reinen Polymerisatsalzes, bezogen auf das Gewicht des Papiers, sowie einige Eigenschaften des erhaltenen Papiers zusammengestellt.A wood-free, unsized offset paper produced on a paper machine with a freeness of 25 ° SR, 14% ash (kaolin) and 2% alum and a weight of 80 g / m 2 is mixed with a 2% aqueous solution of the above-mentioned magnesium salt of the homopolymer impregnated with acrylic acid and then dried at a temperature of 100 ° C. Table 1 shows the viscosity of the preparation solution, the amount of pure polymer salt applied to the paper, based on the weight of the paper, and some properties of the paper obtained.

Vergleichsbeispiel 1aComparative Example 1a

Das im Beispiel 1 beschriebene Homopolymerisat der Acrylsäure wird anstelle.von Magnesiumoxid mit Ammoniak neutralisiert und als 2 %ige Lösung bei einem pH-Wert von 5,0 als Imprägnierungsmittel für das im Beispiel 1 angegebene Offsetpapier verwendet (Tabelle 1).The homopolymer of acrylic acid described in Example 1 is neutralized with ammonia instead of magnesium oxide and used as a 2% solution at a pH of 5.0 as an impregnating agent for the offset paper specified in Example 1 (Table 1).

Vergleichsbeispiel 1bComparative Example 1b

Das im Beispiel 1 beschriebene Homopolymerisat der Acrylsäure wird in nicht neutralisierter Form als 2%ige wäßrige Lösung bei einem pH-Wert von 2,5 als Imprägnierungsmittel für das im Beispiel 1 angegebene Offsetpapier verwendet. In der Tabelle 1 sind die Eigenschaften des erhaltenen Papiers zusammen mit denjenigen Eigenschaften des Papiers zusammengestellt, die nach Behandeln des Papiers mit Wasser und Trocknen gemessen wurden (Vergleichsbeispiel 1c).The homopolymer of acrylic acid described in Example 1 is used in non-neutralized form as a 2% aqueous solution at a pH of 2.5 as an impregnating agent for the offset paper specified in Example 1. Table 1 shows the properties of the paper obtained together with those properties of the paper which were measured after treating the paper with water and drying (comparative example 1c).

(Siehe die Tabelle 1, Seite 4)(See table 1, page 4)

Figure imgb0001
Figure imgb0001

Beispiel 2Example 2

Ein Copolymerisat aus 95 % Acrylsäure und 5 % Acrylamid (hergestellt durch Polymerisieren von Acrylsäure und Acrylamid in wäßriger Lösung mit Kaliumperoxidisulfat als Katalysator wird durch Umsetzung mit Calciumhydroxid in das Calciumsalz (pH-Wert = 6,0) umgewandelt. Eine 2%ige Lösung dieses Copolymerisates wird auf ein holzfreies, ungeleimtes Offsetpapier mit 1 % Alaun, einem Mahlgrad von 25°SR, 10 % Asche (Kaolin) und einem Gewicht von 80 g/m2 aufgebracht.A copolymer of 95% acrylic acid and 5% acrylamide (produced by polymerizing acrylic acid and acrylamide in aqueous solution with potassium peroxydisulfate as a catalyst is converted into the calcium salt (pH = 6.0) by reaction with calcium hydroxide. A 2% solution of this Copolymers are applied to a wood-free, unsized offset paper with 1% alum, a freeness of 25 ° SR, 10% ash (kaolin) and a weight of 80 g / m 2 .

Das imprägnierte Papier wird bei einer Temperatur von 100 °C getrocknet. Weitere Angaben über die Präparationslösung sowie die Eigenschaften des imprägnierten Papiers können der Tabelle 2 entnommen werden.The impregnated paper is dried at a temperature of 100 ° C. Further information on the preparation solution and the properties of the impregnated paper can be found in Table 2.

Vergleichsbeispiel 2aComparative Example 2a

Das im Beispiel 2 beschriebene Copolymerisat aus 95 % Acrylsäure und 5 % Acrylamid wird anstelle von Calciumhydroxid mit Ammoniak neutralisiert und als 2%ige wäßrige Lösung bei einem pH-Wert von 6,0 als Imprägnierungsmittel für das im Beispiel 2 angegebene Offsetpapier verwendet (Tabelle 2).The copolymer of 95% acrylic acid and 5% acrylamide described in Example 2 is neutralized with ammonia instead of calcium hydroxide and used as a 2% aqueous solution at a pH of 6.0 as an impregnating agent for the offset paper specified in Example 2 (Table 2 ).

Vergleichsbeispiel 2bComparative Example 2b

Das im Beispiel 2 angegebene Copolymerisat aus 95% Acrylsäure und 5% Acrylamid wird ohne Neutralisation in Form einer 2 %igen wäßrigen Lösung, die einen pH-Wert von 2,5 hat, zum Imprägnieren von Papier verwendet, das im Beispiel 2 beschrieben ist. Das Papier wurde bei der selben Temperatur getrocknet, wie im Beispiel 2. Die Ergebnisse sind in Tabelle 2 angegeben. Zum Vergleich sind außerdem in Tabelle 2 die Werte angegeben, die man erhält, wenn man das im Beispiel 2 beschriebene Papier mit Waser imprägniert und bei 100 °C trocknet.

Figure imgb0002
The copolymer of 95% acrylic acid and 5% acrylamide specified in Example 2 is used without neutralization in the form of a 2% strength aqueous solution which has a pH of 2.5 for impregnating paper, which is described in Example 2. The paper was dried at the same temperature as in Example 2. The results are shown in Table 2. For comparison, the values are also given in Table 2, which are obtained when the paper described in Example 2 is impregnated with water and dried at 100.degree.
Figure imgb0002

Die Beispiele und Vergleichsbeispiele zeigen, daß die erfindungsgemäß zu verwendenden Polymerisatsalze gegenüber den entsprechenden Ammoniumsalzen bzw. den Polysäuren zu einer weiteren Trockenfestigkeitssteigerung des Papiers führen ohne dabei die Naßfestigkeit des Papiers unerwünscht zu erhöhen.The examples and comparative examples show that the polymer salts to be used according to the invention compared to the corresponding ammonium salts or the polyacids lead to a further increase in the dry strength of the paper without undesirably increasing the wet strength of the paper.

Claims (4)

1. A process for the manufacture of paper having a high dry strength and a low wet strength by treating the surface of paper with an aqueous polymer solution, characterized in that there is used a water-soluble alkaline earth metal salt of a polymer of
a) from 91 to 100 % by weight of acrylic acid and/or methacrylic acid and
b) from 0 to 9% by weight of acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, vinyl acetate, maleic anhydride, diisobutylene, an ester of acrylic acid and/or an ester of methacrylic acid.
2. A process as claimed in claim 1, characterized in that there is used a water-soluble calcium salt and/or magnesium salt of a polymer of
a) from 91 to 100 % by weight of acrylic acid and/or methacrylic acid and
b) from 0 to 9 % by weight of acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, vinyl acetate, maleic anhydride, diisobutylene, an ester of acrylic acid and/or an ester of methacrylic acid, which has a viscosity of from 5 to 100 mPas (measured in a Brookfield viscometer at 20 revolutions per minute) in 2 % by weight strength aqueous solution at 20 °C.
3. A process as claimed in claim 1, characterized in that the alkaline earth metal salt is optionally used in conjunction with an alkali metal salt of the polymer, the ratio of alkaline earth metal salt to alkali metal salt being from 30 to 50 : 70 to 50.
4. A process as claimed in claims 1 to 3, characterized in that the polymer salt is used in an amount of from 1 to 4 % by weight, based on dry paper.
EP80100302A 1979-01-27 1980-01-22 Process for producing a paper having a high dry-strength and a low wet-strength Expired EP0013969B1 (en)

Priority Applications (1)

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AT80100302T ATE1591T1 (en) 1979-01-27 1980-01-22 PROCESS FOR MAKING PAPER WITH HIGH DRY STRENGTH AND LOW WET STRENGTH.

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DE19792903218 DE2903218A1 (en) 1979-01-27 1979-01-27 METHOD FOR PRODUCING PAPER WITH HIGH DRY RESISTANCE AND LOW WET STRENGTH
DE2903218 1979-01-27

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EP0013969B1 true EP0013969B1 (en) 1982-09-22

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DE3506832A1 (en) * 1985-02-27 1986-08-28 Basf Ag, 6700 Ludwigshafen METHOD FOR PRODUCING PAPER WITH HIGH DRY RESISTANCE
CA2004296A1 (en) * 1988-11-30 1990-05-31 Shusuke Kakiuchi Water-disintegrable cleaning sheet
US5281306A (en) * 1988-11-30 1994-01-25 Kao Corporation Water-disintegrable cleaning sheet
JP2584508B2 (en) * 1989-02-28 1997-02-26 花王株式会社 Water disintegration paper for cleaning supplies
FR2670516B1 (en) * 1990-12-13 1993-04-09 Hoechst France PROCESS FOR COATING PAPERS AND ITS APPLICATION TO FLEXOGRAPHY.
US5266162A (en) * 1990-12-13 1993-11-30 Societe Francaise Hoechst Process for coating papers and its use in flexographic printing
JP3030976B2 (en) * 1991-09-09 2000-04-10 荒川化学工業株式会社 Rosin emulsion size for papermaking
US5741572A (en) * 1995-02-17 1998-04-21 Lexmark International, Inc. Heat fixing paper or sheet
DE19607674A1 (en) * 1996-02-29 1997-09-04 Basf Ag Use of hydrolyzed polymers of N-vinylcarboxamides as an agent for increasing the dry strength of paper, cardboard and cardboard
DE19758479C2 (en) * 1997-07-02 2002-07-11 Koehler Decor Gmbh & Co Kg impregnating
RU2361853C2 (en) 2003-08-14 2009-07-20 Басф Акциенгезельшафт Method of producing (met)acrolein and/or (met)acrylic acid
US7390846B2 (en) * 2004-11-30 2008-06-24 Crompton Corporation Wood sizing agents for PVC composites
DE102007010422A1 (en) 2007-03-01 2008-09-04 Basf Se Preparation of a catalyst, useful in the heterogeneously catalyzed partial gas phase oxidation of acrolein to acrylic acid, comprises attaching one of the active mass to the surface of the carrier body with the help of a binding agent
DE102009047291A1 (en) 2009-11-30 2010-09-23 Basf Se Producing (meth)acrolein, by heterogeneous catalyzed gas phase-partial oxidation, comprises guiding reaction gas mixture through a fresh fixed catalyst bed present in a reactor at increased temperature
DE102010048405A1 (en) 2010-10-15 2011-05-19 Basf Se Long term operation of heterogeneously catalyzed partial gas phase oxidation of propene to acrolein, comprises conducting reaction gas input mixture containing propene, molecular oxygen and inert gas, through solid catalyst bed
DE102011076931A1 (en) 2011-06-03 2012-12-06 Basf Se Aqueous solution containing acrylic acid and its conjugate base

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FR931044A (en) 1945-02-09 1948-02-11 Ici Ltd Paper treatment process
GB1216337A (en) 1967-08-30 1970-12-16 William Nash Ltd Production of paper base materials
JPS52132A (en) * 1975-06-23 1977-01-05 Nec Corp Memory
JPS5218803A (en) * 1975-08-05 1977-02-12 Nippon Zatsuka Shinkou Sentaa Method of molding wood product
DE2741753B1 (en) 1977-09-16 1979-03-22 Basf Ag Process for making paper with high dry strength and low wet strength

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FI64964B (en) 1983-10-31
DE2903218A1 (en) 1980-08-07
US4294873A (en) 1981-10-13
NO157186B (en) 1987-10-26
ATE1591T1 (en) 1982-10-15
EP0013969A1 (en) 1980-08-06
NO157186C (en) 1988-02-03
DE3060860D1 (en) 1982-11-04
JPS55103393A (en) 1980-08-07
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FI64964C (en) 1984-02-10
ES8105058A2 (en) 1981-04-01

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