WO2017021917A1 - Finely divided, anionic, aqueous polymer dispersions, processes for the preparation and use as sizes in papermaking - Google Patents

Finely divided, anionic, aqueous polymer dispersions, processes for the preparation and use as sizes in papermaking Download PDF

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Publication number
WO2017021917A1
WO2017021917A1 PCT/IB2016/054704 IB2016054704W WO2017021917A1 WO 2017021917 A1 WO2017021917 A1 WO 2017021917A1 IB 2016054704 W IB2016054704 W IB 2016054704W WO 2017021917 A1 WO2017021917 A1 WO 2017021917A1
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weight
finely divided
acrylate
ethylenically unsaturated
added
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PCT/IB2016/054704
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French (fr)
Inventor
Klaus Moeller
Carmen-Elena Cimpeanu
Petra Arnold
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Basf Se
Basf (China) Company Limited
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Publication of WO2017021917A1 publication Critical patent/WO2017021917A1/en

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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F2/00—Processes of polymerisation
    • C08F2/12—Polymerisation in non-solvents
    • C08F2/16—Aqueous medium
    • C08F2/22—Emulsion polymerisation
    • C08F2/24—Emulsion polymerisation with the aid of emulsifying agents
    • C08F2/26—Emulsion polymerisation with the aid of emulsifying agents anionic
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F257/00—Macromolecular compounds obtained by polymerising monomers on to polymers of aromatic monomers as defined in group C08F12/00
    • C08F257/02—Macromolecular compounds obtained by polymerising monomers on to polymers of aromatic monomers as defined in group C08F12/00 on to polymers of styrene or alkyl-substituted styrenes
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F265/00—Macromolecular compounds obtained by polymerising monomers on to polymers of unsaturated monocarboxylic acids or derivatives thereof as defined in group C08F20/00
    • C08F265/02—Macromolecular compounds obtained by polymerising monomers on to polymers of unsaturated monocarboxylic acids or derivatives thereof as defined in group C08F20/00 on to polymers of acids, salts or anhydrides
    • 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
    • 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
    • D21H17/35—Polyalkenes, e.g. polystyrene
    • 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
    • D21H17/37—Polymers of unsaturated acids or derivatives thereof, e.g. polyacrylates
    • 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
    • D21H21/14—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 function or properties in or on the paper
    • D21H21/16—Sizing or water-repelling agents
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F212/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an aromatic carbocyclic ring
    • C08F212/02—Monomers containing only one unsaturated aliphatic radical
    • C08F212/04—Monomers containing only one unsaturated aliphatic radical containing one ring
    • C08F212/06—Hydrocarbons
    • C08F212/08—Styrene

Definitions

  • Finely divided, anionic, aqueous polymer dispersions processes for the preparation and use as sizes in papermaking.
  • the invention relates to finely divided, aqueous polymer dispersions which are obtainable by emulsion polymerization of ethylenically unsaturated monomers in an aqueous medium containing a protective colloid, processes for the preparation of the dispersions and their use as sizes for paper, board and paperboard.
  • EP 0 276 770 B1 and EP 0 257 412 B2 disclose sizes based on finely divided, aqueous dispersions which are obtainable by copolymerization of ethylenically unsaturated monomers, such as acrylonitrile and (meth)acrylates and optionally up to 10% by weight of other monomers, such as styrene, by an emulsion polymerization in the presence of initiators comprising peroxide groups, in particular of redox initiators, and degraded starch.
  • chain-transfer agents such as terpenes, is not disclosed in any of the documents.
  • WO 99/42490 A1 likewise discloses aqueous, finely divided polymer dispersions which are used for the surface sizing of paper, board and cardboard.
  • the dispersions are obtainable by free radical emulsion polymerization of ethylenically unsaturated monomers in the presence of degraded starch having a number average molecular weight M n of from 500 to 10,000.
  • the monomers consist of (i) at least one optionally substituted styrene, (ii) at least one C C 4 -alkyl (meth)acrylate and (iii) optionally up to 10% by weight of other ethylenically unsaturated monomers.
  • the polymerization is effected in the presence of a graft-linking, water-soluble redox sys- tern.
  • chain-transfer agents from the group consisting of the mercaptans is disclosed for adjusting the molecular weight.
  • WO 2002/14393 A1 discloses a process for the preparation of polymer dispersions which are used as sizes and coating materials. These polymer dispersions are obtainable by emulsion copolymerization of a monomer mixture comprising at least one (meth)acrylate of monohydric, saturated Cs-Cs-alcohols an at least one further ethylenically unsaturated monomer in the presence of a starch or of a starch derivative and of an initiator comprising peroxide groups.
  • the emulsion polymerization is distinguished in that both the monomers and the initiator are metered in continuously, a first amount of initiator being metered in within a first feed period of from 5 to 60 minutes and a second amount of initiator which is smaller than the first amount of initiator being metered in within a second feed period of from 5 to 180 minutes.
  • the use of chain- transfer agents is not disclosed.
  • Finely divided, starch-containing polymer dispersions as sizes for paper, board and cardboard are also disclosed in WO 2007/000419 A1 . These are obtainable by emulsion polymerization, in an aqueous medium, using redox initiators, of ethylenically unsaturated monomers comprising (i) at least one optionally substituted styrene, methyl methacrylate, acrylonitrile and/or methacry- lonitrile, (ii) at least one Ci-Ci2-alkyl (meth)acrylate and at least (iii) one ethylenically unsaturat- ed copolymerizable monomer in the presence of a degraded, cationic starch which has a molar mass M w of from 1000 to 65 000 g/mol.
  • WO 2007/000420 A1 likewise discloses finely divided, aqueous, starch-containing polymer dispersions as sizes for paper, board and cardboard, which are obtainable by free radical emulsion polymerization of (i) at least one optionally substituted styrene, methyl methacrylate, acrylonitrile and/or methacrylonitrile, (ii) at least one Ci-C4-alkyl methacrylate, (iii) at least one Cs-C22-alkyl (meth)acrylate and (iv) optionally at least one other ethylenically copolymerizable monomer and (v) a degraded starch having a molar mass M w of from 1000 to 65 000 in the presence of a chain-transfer agent.
  • tert-dodecyl merpatan is the preferred chain-transfer agent, which is also used in all examples.
  • WO 201 1/039185 discloses a finely divided, starch containing polymer dispersions which are obtained by free radical emulsion polymerisation of ethylenically unsaturated monomers in the presence of at least one redox initiator and starch.
  • the polymers are formed by polymerisation of at least one optionally substituted styrene, at least one Ci-Ci2-alkyl acrylate or methacrylate and optionally other ethylenically unsaturated monomer.
  • the polymerisation employs at least one terpene-containing chain-transfer agent.
  • WO2013053840 teaches a finely divided, starch containing polymer dispersion obtainable by free radical emulsion polymerisation of a monomer mixture comprising less than 40% by weight, at least one optionally substituted styrene, and from greater than 60 to 100% by weight of at least one Ci-Ci2-alkyl acrylate or methacrylate and optionally other ethylenically unsaturated monomer.
  • the polymerisation is carried out in at least one degraded starch, which has a molar mass Mw of from 1000 to 65,000 g/mol and in the presence of at least 0.01 % by weight, based on the monomers, of at least one chain transfer agent.
  • the polymer dispersion optionally comprises an aluminium compound.
  • DE69725779 discloses latex dispersions, for instance resulting from the polymerisation of a mixture of hydrophobic monomers composed of styrene and of (meth) acrylic esters emulsion in an aqueous solution of water-soluble or water dispersible amphiphilic copolymer consisting of a combination of hydrophobic monomers and hydrophilic monomers bearing carboxylic acid func- tions, in the presence of claim radical initiator.
  • the amphiphilic copolymer has a molecular mass of between 500 and 5000. Examples of amphiphilic copolymers include polymers of maleic anhydride and styrene. This disclosure describes the application of such latex dispersions to the bonding of papers.
  • the objective of the present invention is to provide finely divided, anionic polymer aqueous dispersions which are effective surface sizing agents for paper, board and cardboard.
  • a further objective of the present invention is to provide such a polymer dispersion in which a synthetic protective colloid is employed.
  • the present invention relates to a finely divided, anionic, aqueous polymer dispersion which is obtainable by emulsion polymerisation of a mixture of ethylenically unsaturated monomers in an aqueous medium containing a protective colloid, in which the mixture of ethylenically unsaturated monomers comprises: (a) from 40 to 90% by weight of at least one optionally substituted styrene;
  • aqueous polymer dispersions have been found to be very useful surface sizing agents for paper, board and cardboard.
  • the present invention also relates to a process for the preparation of a finely divided, anionic, aqueous polymer dispersion, in which a mixture of ethylenically unsaturated monomers comprising:
  • an at least partially hydrolysed polymer we mean that at least some of the anhydride groups of the maleic anhydride repeating units have been hydrolysed to carboxylic acid functional groups or salts of carboxylic acid functional groups, such as ammonium salts or alkali metal salts, such as sodium or potassium.
  • carboxylic acid functional groups or salts of carboxylic acid functional groups such as ammonium salts or alkali metal salts, such as sodium or potassium.
  • from 30% to 100% of the anhydride groups have been hydrolysed to carboxylic acid groups or salts thereof.
  • from 50% to 100% of the anhydride groups have been hydrolysed.
  • 70 or 80% up to 90 or 100% of the anhydride groups have been hydrolysed.
  • the protective colloid may desirably be formed from
  • the components of the protective colloid should be (i) from 55 to 90% by weight of at least one optionally substituted styrene; and (ii) from 10 to 45% by weight of maleic anhydride. More preferably component (i) should be from 60 to 85% or from 65 to 85%, most preferably from 65 to 80%, by weight of at least one optionally substituted styrene; and more preferably component (ii) should be from 15 to 40% or from 15 to 35%, most preferably from 20 to 35%, by weight of maleic anhydride.
  • the protective colloid may exhibit an acid number of up to 500 mg of potassium hydroxide per gram of polymer (mg KOH/g).
  • the acid number may be from 100 to 500 mg KOH/g.
  • the acid number should be from 200 to 400 mg KOH/g and more preferably from 250 to 350 mg KOH/g. This may be determined by standard test method ASTM D 3644-06 (2012).
  • the protective colloid may have a glass transition temperature (Tg) of from 80°C to 200°C, such as from 100°C to 200°C, suitably from 1 10°C to 180°C, for instance from 120°C to 170°C. Glass transition temperature may be determined by the test method given according to ISO 3146.
  • the protective colloid is a polymer having a weight average molar mass of at least 8,000 g/mol, for instance from 8,000 to 500,000 g/mol.
  • the weight average molar mass may be at least 9,000 g/mol, for instance from 9,000 to 400,000 g/mol.
  • the weight average molar mass may be at least 10,000 g/mol, for instance from 10,000 to 300,000 g/mol.
  • the weight average molar mass should be at least 20,000 g/mol, for instance from 20,000 to 200,000 g/mol, preferably in the range of from 50,000 to 150,000 g/mol.
  • Weight average molar mass (Mw) may for instance be determined by standard techniques such as Gel Permeation Chromatography (GPC). Typically the GPC technique may use aqueous eluents and an apparatus combination from Agilent, for instance series 1 100.
  • the eluent may be THF (tetrahydrofuran) with 0.1 % trifluroacetic acid.
  • the separation should take place in a separating column combination. Suitable column numbers are for instance 1621 , 1512 and 1626 (7.5 mm x 5 cm, 7.5 mm x 30 cm and 7.5 mm x 30 cm, respectively) adding as the separation material Plgel 10 ⁇ Guard, Plgel 10 ⁇ and Plgel 10 ⁇ , respectively.
  • the flow rate can be in the region of 1 ml/min, and a column temperature of 35°C.
  • any suitable amount of the protective colloid may be used to prepare the polymer dispersion.
  • the amount of protective colloid may be from 20% to 70 or 80% or more by weight of active protective colloid on the total active content of the monomer mixture.
  • the amount of protective colloid should be at least 30% and preferably from 40% to 50%.
  • active protective colloid we mean on the basis of 100% polymeric protective colloid.
  • total active content of the monomer mixture we mean 100% of the monomers in the monomer mixture.
  • Monomers of group (i) of the protective colloid and independently group (a) are optionally substituted styrenes.
  • This group includes styrene and substituted styrenes, such as, for example, a- methylstyrene, styrenes halogenated on the ring, such as chlorostyrene, or Ci-C4-substituted styrenes, such as vinyltoluene.
  • styrene and substituted styrenes such as, for example, a- methylstyrene, styrenes halogenated on the ring, such as chlorostyrene, or Ci-C4-substituted styrenes, such as vinyltoluene.
  • a preferably used monomer of this group is styrene, which is preferably used alone from this group.
  • the monomers of group (a) are present in an amount of from 40% to 90% by weight, preferably from 50% to 85% by weight, in the ethylenically unsaturated monomer mixture comprising (a), (b), (c) and (d). More preferably monomers of group (a) may be present in an amount of from 55% to 85% by weight, often from 60% to 80%, typically from 65% to 75% by weight.
  • Suitable monomers of group (b) are all esters of acrylic acid and of methacrylic acid which are derived from monohydric Ci-Ci2-alcohols, such as methyl acrylate, ethyl acrylate, ethyl methac- rylate, n-propyl acrylate, n-propyl methacrylate, isopropyl acrylate, isopropyl methacrylate, n- butyl acrylate, n-butyl methacrylate, isobutyl acrylate, isobutyl methacrylate, tert-butyl acrylate, tert-butyl methacrylate, sec-butyl acrylate, sec-butyl methacrylate, n-pentyl acrylate, n-pentyl methacrylate, neopentyl acrylate, neopentyl methacrylate, cyclohexyl acrylate, cyclo
  • Preferably used monomers of this group are esters of acrylic acid and methacrylic acid with Ci-Cs-alcohols, such as methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, sec-butyl acrylate, isobutyl acrylate, tert-butyl acrylate, cyclohexyl acrylate, 2-ethylhexyl acrylate and 2-ethylhexyl methacrylate.
  • Ci-Cs-alcohols such as methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, sec-butyl acrylate, isobutyl acrylate, tert-butyl acrylate, cyclohexyl acrylate, 2-ethylhexyl acrylate
  • esters of acrylic acid with Ci-C 4 -alcohols such as n-butyl acrylate, sec-butyl acrylate, isobutyl acrylate and tert-butyl acrylate are particularly preferred. Of these n-butyl acrylate and tert-butyl acrylate are examples of especially preferred monomers of this group.
  • At least one Ci-Ci2-alkyl acrylate and/or Ci-Ci2-alkyl methacrylate is used as a monomer of group (b), for example two or more of the abovementioned esters in any desired mixtures with one another.
  • group (b) Preferably only one monomer from the group (b) is used as a monomer of the group and particularly preferably a monomer from the group consisting of the esters of acrylic acid with C C 4 -alcohols.
  • the monomers of group (b) are present in an amount of from 10 to 60% by weight, preferably from 15 to 50% by weight, in the ethylenically unsaturated monomer makes the comprising (a), (b), (c) and (d). More preferably the monomers of group (b) may be present in an amount of from 15 to 45% by weight, often from 20 to 40%, typically from 25 to 35% by weight.
  • the monomers of group (a) are present in an amount of from 40% to 90% by weight, preferably from 50% to 85% by weight, in the ethylenically unsaturated monomer mixture comprising (a), (b), (c) and (d). More preferably monomers of group (a) may be present in an amount of from 55% to 85% by weight, often from 60% to 80%, typically from 65% to 75% by weight.
  • Examples of monomers of group (c) are ethylenically unsaturated C3- to carboxylic acids, such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, ethacrylic acid, crotonic acid, monoesters of ethylenically unsaturated dicarboxylic acids, such as mono methyl maleate, mono methyl fumarate, mono ethyl maleate, mono ethyl fumarate, mono propyl male- ate, mono propyl, fumarate, mono-n-butyl maleate, mono-n-butyl fumarate, and styrene carboxylic acids and ethylenically unsaturated anhydrides, such as maleic anhydride and itaconic an- hydride.
  • carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, ethacrylic acid, crotonic acid
  • the anhydride group of monomers may be hydrolysed to carboxyl groups.
  • monomers comprising sulpho- and/or phosphonic acid groups such as 2-acrylamido-2-methyl propane sulphonic acid and vinyl phosphonic acid, are suitable as monomers (c).
  • the monomers comprising acid groups can be used in the form of free acid groups and in the form of partly or completely neutralised with alkali metal bases, alkaline earth metal bases, ammonia and/or amines.
  • sodium hydroxide solution, potassium hydroxide solution, sodium carbonate, sodium bicarbonate, ammonia, trimethyl amine, triethyl amine, morpholine, ethanola- mine, diethanolamine, triethanolamine, or diethylene triamine is used for neutralising the acid groups of the monomers. It is of course possible to use two or more bases as neutralising agents. From this group of monomers, acrylic acid and methacrylic acid or mixtures of acrylic acid and methacrylic acid in any desired ratio are preferably used. The monomers of group (c) are present in an amount of from 0 to 5% by weight.
  • these monomers may be included in an amount of from 0.5 to 5% by weight, suitably from 0.7 to 3.5% by weight, for instance between 1.5 and 2.5% by weight, such as around 2% by weight, in the monomer mixture comprising (a) to (d).
  • Component (d) of the monomer mixture used for the preparation of the above mentioned resin can, if appropriate, comprise non-ionic, ethylenically unsaturated monomers which are different from the monomers (a) or (b).
  • monomers are amides, such as, for example, acrylamide, methacrylamide, N-methyl acrylamide, N-methyl methacrylamide, N-ethyl acryla- mide and N-ethyl methacrylamide; vinyl compounds, such as vinyl acetate, vinyl propionate or vinylformamide; Ci3-3o alkyl (meth) acrylates.
  • the alkyl moiety of the ester may contain between 13 and 30 carbon atoms, such as, for example, tridecyl acrylate, tridecyl methacrylate, tetradecyl acrylate, tetradecyl methacrylate, pentadecyl acrylate, pentadecyl methacrylate, hex- a
  • esters of acrylic acid or methacrylic acid having been prepared by reacting at least one ethylene oxide unit, for example hydroxyl ethyl methacrylate or diethylene glycol monomethacrylate.
  • suitable monomers of this group include acryloni- trile and methacrylonitrile. It is of course also possible to use mixtures of said monomers. If the monomers group (d) are used, they are present in an amount of up to 20% by weight, in general in an amount of up to 10% by weight, for instance in an amount of up to 5% by weight, based on the total amount of monomers (a) to (d) in the monomer mixture.
  • these monomers may be included in an amount of from 0.5 to 5% by weight, suitably from 0.7 to 3.5% by weight, in the monomer mixture comprising monomers (a) to (d) in the monomer mixture.
  • the sum of the values in % by weight for the monomers (a) to (d) is always 100.
  • Preferred finely divided, anionic, aqueous polymer dispersions are those in which the monomer mixture employed in the emulsion polymerisation comprises (a) from 60 to 80% by weight of at least one optionally substituted styrene;
  • More preferred finely divided, anionic, aqueous polymer dispersions are those in which the monomer mixture employed in the emulsion polymerisation comprises
  • a particularly preferred finely divided, anionic, aqueous polymer dispersion which is obtainable by emulsion polymerisation of a mixture of ethylenically unsaturated monomers in an aqueous medium containing a protective colloid, in which the mixture of ethylenically unsaturated monomers comprises:
  • the protective colloids described above are used for stabilising the monomer emulsions.
  • the emulsion polymerisation is effected in general in a temperature range of from 40 to 150°C, preferably from 60 to 90°C.
  • the emulsion polymerisation is conducted in the presence of second polymerisation initiators, which are preferably water-soluble.
  • Initiators for the emulsion polymerisation may be used in any conventional amount. In general, from 0.2 to 5%, preferably from 0.4 to 3.5 %, more preferably 0.5 to 2.5% by weight of at least one initiator, based on the monomer is to be polymerised are used.
  • Suitable second polymerisation initiators for use in the emulsion polymerisation are, for example, azo compounds, peroxides, hydroperoxides, inorganic peroxides and redox systems, such as combinations of hydrogen peroxide and ascorbic acid or tert-butyl hydroperoxide and ascorbic acid.
  • the redox systems can moreover comprise metal cations, such as cerium, manganese or iron(ll) ions, for activation.
  • the monomers can either be metered directly into the initially taken mixture or they can be fed in the form of an aqueous emulsion or mini emulsion to the polymerisation batch.
  • a part of the aqueous solution and/or colloidal dispersion of the protective colloid described above optionally diluted with water can be used as an emulsifier, or the monomers maybe emulsifier with the aid of customary non-ionic, anionic, cationic or amphoteric emulsifiers in water.
  • Customary emulsifiers may be used if desired.
  • the amounts used are, for example, from 0.05 to 3% by weight and preferably in the range from 0.5 to 2% by weight, based on the combined weight of total monomer components (a) + (b) + (c) + (d) and protective colloid.
  • Customary emulsifiers are described in detail in the literature, cf. for example M. Ash, I. Ash, Handbook of Industrial Surfactants, Third Edition, Synapse Information Resources Inc.
  • customary emulsifiers include the reaction products of long chain monohydric alcohols (C10- to C22- alkanols) with from 4 to 80 mol of ethylene oxide and/or propylene oxide per mole of alcohol or ethoxylated phenols or alkoxylated alcohols esterified with sulphuric acid, which are generally used in the form neutralised with alkalis.
  • emulsifiers are, for example, sodium alkane sulphonates, sodium alkyl sulphates, sodium dodecylbenzene sulphonates, sulpho- succinate esters, quaternary alkyl ammonium salts, alkyl benzyl ammonium salts, such as dime- thyl-Ci2 to Cis-alkyl benzyl ammonium chlorides, primary, secondary and tertiary fatty amine salts, quaternary amido amine compounds, alkylpyridinium salts, alkyl imidazolinium salts and alkyl oxazolinium salts.
  • no emulsifiers are used.
  • the metering of the monomers for carrying out emulsion polymerisation can be effected continuously or batchwise.
  • the metering of the monomers can be effected as a mixture or separately or in a manner of a step or gradient procedure.
  • the addition can be effected uniformly or non-uniformly, i.e. with a changing metering rate, over the metering period.
  • the first polymerisation for the preparation of the resin and/or the emulsion polymerisation is/are carried out in the presence of polymerisation regulators.
  • Suitable regulators are, for example, mercaptans, such as ethyl mercaptan, n- butyl mercaptan, tert-butyl mercaptan, n-dodecyl mercaptan or tetradodecyl mercaptan, thiogly- colic acid, 2-mercaptoethanol and 2-ethylhexyl thioglycolate, carbon tetrabromide, or isopropa- nol.
  • suitable regulators are from the class consisting of the terpenes, preferably from the class consisting of the monocyclic terpenes and particularly preferably from a group consisting of the menthadienes.
  • terpinolene is very particularly preferred.
  • the amounts of regulator are, For example, from 0.1 to 10% by weight, preferably for 0.3 to 5% by weight.
  • the pH of the reaction mixture is, for example, in the range from 6 to 12, in general from 7 to 10, in the polymerisation stage.
  • the emulsion polymerisation may be carried out at a temperature higher than ambient (i.e. higher than 25°C).
  • the polymerisation may be carried out at temperatures from 70 to 95°C, suitably from 75 to 95°C, particularly from 80 to 90°C.
  • a post polymerisation is expediently carried out after the end of the emulsion polymerisation.
  • an initiator from the group consisting of hydroperoxide, peroxides, such as hydrogen peroxide, and/or azo initiators is added to the polymer dispersion after the end of the main polymerisation.
  • suitable reducing agents such as, for example, ascorbic acid or sodium bisulphite, is also possible.
  • Oil soluble, sparingly water-soluble initiators are preferably used, for example customary organic peroxides, such as dibenzoyl peroxide, di-tert-butyl peroxide, tert-butyl hydroperoxide, cumyl hydroperox- ide or biscyclohexyl peroxybicarbonate.
  • the reaction mixture is heated, for example, to a temperature which corresponds the temperature at which the main polymerisation was carried out or which is up to 20°C, preferably up to 10°C, lower.
  • the main polymerisation is complete when the polymerisation initiator has been consumed or the monomer conversion is, for example, at least 98%, preferably at least 99.5%.
  • tert-butyl hydroperoxide is preferably used.
  • the polymerisation is carried out, for example, in a temperature range of from 40 to 1 10°C, in general from 50 to 105°C.
  • the mean particle size of the dispersed particles is, for example 5 to 250 nm, preferably less than 120 nm, particularly preferably from 10 to 100 nm.
  • the mean particle size can be determined by methods known to the person skilled in the art, such as, for example, laser correlation spectroscopy, ultracentrifuging or CHDF.
  • a further measure of the particle size of the dispersed polymer particles is the LT value.
  • the polymer dispersion to be investigated in each case is measured in 0.1 % strength by weight aqueous formulation in a cell having an edge length of 2.5 cm with light of wavelength 600 nm.
  • the mean particle size can be calculated from the measured values of cf. B. Verner, M. Barta, B. Sedlacek, Tables of Scattering Functions For Spherical Particles, Prague 1976, Edice Marco, Rada D-DATA, SVAZEK D-1.
  • the polymer concentration of the aqueous dispersions obtained in the emulsion polymerisation is, for example, from 10 to 40, preferably from 15 to 30% by weight.
  • the finely divided, anionic aqueous polymer dispersions described above are used as sizing agents for paper, board and cardboard. They can be used for the production of all paper varie- ties, for example of writing and printing papers and packaging paper is and papers for the packaging of liquids. They are suitable particular for the surface sizing of paper products.
  • the dispersions according to the invention can be processed by all methods suitable in surface sizing, but they can also be used for internal sizing.
  • the aqueous polymer dispersions are diluted by adding water, generally to a polymer content, for example, from 0.05 to 5% by weight. The amount of polymer dispersion depends on the desired degree of sizing of the papers or paper products to be finished.
  • Such preparation solutions can, if appropriate, comprise further substances, for example starch, dyes, optical brighteners, biocides, paper strength agents, fixing agents, antifoams, retention aids and/or drainage aids.
  • the size dispersion can be applied to paper, board or cardboard by means of a size press or other application units, such as film press, speed size or gate roll.
  • the amount of polymer which is applied to the surface of the paper products is, for example, from 0.005 to 1.0 g/m 2 , preferably from 0.01 to 0.5 g/m 2 .
  • the polymer dispersions according to the invention exhibit an excellent sizing effect on papers produced with a variety of fibre types from unbleached softwood, unbleached deciduous wood, unbleached hardwood, bleached softwood, bleached deciduous wood, bleached hardwood, deinked fibres or mixtures of different fibre types. Furthermore, the dispersions according to the invention exhibit very good compatibility with the customary starches, for example potato starch, cornstarch, wheat starch, tapioca starch. Moreover, the dispersions according to the invention exhibit complete development of sizing after the production and drying of the paper web.
  • the monomer feed consisting of 25.2 g of styrene, 10.80 g of n-butyl acrylate, 0.15 g of a 40% by weight Emulga- torTM K 30 (available from Bayer) solution and 39 g of demineralized water was also started and fed over 120 min.
  • 12 g of demineralized water is added to the reactor and after the completion of the initiator feed the polymerization mixture was further stirred for 30 min. Afterwards 1.2 g of a 10% by weight tert- butyl hydroperoxide solution were added to the reactor and polymerization mixture was then stirred for another 30 min.
  • the polymerization mixture is cooled down to room temperature.
  • a finely divided polymer dispersion having a solids content of 17.8% by weight and a particle size of 36 nm (HPPS) was obtained.
  • the initiator feed consisting of 9.0 g of a 5% by weight sodium peroxodisulfate solution in water was started and fed into the reactor over 150 min.
  • the monomer feed consisting of 25.2 g of styrene, 10.80 g of n-butyl acrylate, 0.15 g of a 40% by weight Emulga- torTM K 30 (available from Bayer) solution and 39 g of demineralized water was also started and fed over 120 min.
  • the monomer feed consisting of 30.0 g of styrene, 12.0 g of n-butyl acrylate, 0.15 g of a 40% by weight Emulga- torTM K 30 (available from Bayer) solution and 39 g of demineralized water was also started and fed over 120 min.
  • 12 g of demineralized water is added to the reactor and after the completion of the initiator feed the polymerization mixture was further stirred for 30 min. Afterwards 1.2 g of a 10% by weight tert- butyl hydroperoxide solution were added to the reactor and polymerization mixture was then stirred for another 30 min.
  • the polymerization mixture is cooled down to room temperature.
  • a finely divided polymer dispersion having a solids content of 21.4% by weight and a particle size of 177 nm (HPPS) was obtained.
  • the initiator feed consisting of 9.0 g of a 5% by weight sodium peroxodisulfate solution in water was started and fed into the reactor over 150 min.
  • the monomer feed consisting of 25.2 g of styrene and 10.80 g of n-butyl acrylate was also started and fed over 120 min.
  • the end of the monomer feed 6 g of demineralized water is added to the reactor and after the completion of the initiator feed the polymerization mixture was further stirred for 30 min.
  • the initiator feed consisting of 9.0 g of a 5% by weight sodium peroxodisulfate solution in water was started and fed into the reactor over 150 min.
  • the monomer feed consisting of 30 g of styrene and 12 g of n-butyl acrylate was also started and fed over 120 min.
  • the end of the monomer feed 6 g of demineralized water is added to the reactor and after the completion of the initiator feed the polymerization mixture was further stirred for 30 min.
  • Example 12 Dispersion 12 (GM 0197-0786)
  • the monomer feed consisting of 33 g of styrene and 15 g of n-butyl acrylate was also started and fed over 120 min.
  • 6 g of demineralized water is added to the reactor and after the completion of the initiator feed the polymerization mixture was further stirred for 30 min.
  • 1.2 g of a 10% by weight tert- butyl hydroperoxide solution were added to the reactor and polymerization mixture was then stirred for another 30 min.
  • the polymerization mixture is cooled down to room temperature.
  • a finely divided polymer dispersion having a solids content of 26.2 % by weight and a particle size of 259 nm (HPPS) was obtained.
  • the monomer feed consisting of 30 g of styrene, 15 g of n-butyl acrylate, 0.1 g of a 58% by weight LumitenTM ISC (available from BASF) solution and 24 g of demineralized water was also started and fed over 120 min.
  • 6 g of demineralized water is added to the reactor and after the completion of the initiator feed the polymerization mixture was further stirred for 30 min. Afterwards 1.2 g of a 10% by weight tert- butyl hydroperoxide solution were added to the reactor and polymerization mixture was then stirred for another 30 min.
  • the polymerization mixture is cooled down to room temperature.
  • a finely divided polymer dispersion having a solids content of 26.3% by weight and a particle size of 166 nm (HPPS) was obtained.
  • the monomer feed consisting of 30 g of styrene, 15 g of n-butyl acrylate, 0.1 g of a 58% by weight LumitenTM ISC (available from BASF) solution and 24 g of demineralized water was also started and fed over 120 min.
  • 6 g of demineralized water is added to the reactor and after the completion of the initiator feed the polymerization mixture was further stirred for 30 min.
  • 1.2 g of a 10% by weight tert- butyl hydroperoxide solution were added to the reactor and polymerization mixture was then stirred for another 30 min.
  • the polymerization mix- ture is cooled down to room temperature.
  • a finely divided polymer dispersion having a solids content of 27.1 % by weight and a particle size of 246 nm (HPPS) was obtained.
  • the monomer feed consisting of 30 g of styrene, 15 g of n-butyl acrylate, 0.1 g of a 58% by weight LumitenTM ISC (available from BASF) solution, 0.3 g of 2-ethylhexyl thioglycolate and 24 g of demineralized water was also started and fed over 120 min.
  • 6 g of demineralized water is added to the reactor and after the completion of the initiator feed the polymerization mixture was further stirred for 30 min.
  • Example 20 Dispersion 20
  • the monomer feed consisting of 30 g of styrene, 15 g of n-butyl acrylate, 0.1 g of a 58% by weight LumitenTM ISC (available from BASF) solution, 0.3 g of 2-ethylhexyl thioglycolate and 24 g of demineralized water was also started and fed over 120 min.
  • 6 g of demineralized water is added to the reactor and after the completion of the initiator feed the polymeriza- tion mixture was further stirred for 30 min.
  • the monomer feed consisting of 27 g of styrene, 12 g of n-butyl acrylate, 0.1 g of a 58% by weight LumitenTM ISC (available from BASF) solution and 24 g of demineralized water was also started and fed over 120 min.
  • 6 g of demineralized water is added to the reactor and after the completion of the initiator feed the polymerization mixture was further stirred for 30 min. Afterwards 1.2 g of a 10% by weight tert- butyl hydroperoxide solution were added to the reactor and polymerization mixture was then stirred for another 30 min.
  • the polymerization mixture is cooled down to room temperature.
  • a finely divided polymer dispersion having a solids content of 20.2% by weight and a particle size of 123 nm (HPPS) was obtained.
  • the monomer feed consisting of 27 g of styrene, 12 g of n-butyl acrylate, 0.1 g of a 58% by weight LumitenTM ISC (available from BASF) solution and 24 g of demineralized water was also started and fed over 120 min.
  • 6 g of demineralized water is added to the reactor and after the completion of the initiator feed the polymerization mixture was further stirred for 30 min. Afterwards 1.2 g of a 10% by weight tert- butyl hydroperoxide solution were added to the reactor and polymerization mixture was then stirred for another 30 min.
  • the polymerization mixture is cooled down to room temperature.
  • a finely divided polymer dispersion having a solids content of 21.1 % by weight and a particle size of 158 nm (HPPS) was obtained.
  • the monomer feed consisting of 42 g of styrene, 18 g of n-butyl acrylate and 0.56 g of Terpinolene (90% by weight) was also started and fed over 120 min.
  • 10 g of demineralized water is added to the reactor and after the completion of the initiator feed the polymerization mixture was further stirred for 30 min.
  • 2 g of a 10% by weight tert- butyl hydroperoxide solution were added to the reactor and polymerization mixture was then stirred for another 30 min.
  • the polymerization mixture is cooled down to room temperature.
  • a finely divided polymer dispersion having a solids content of 21 .8% by weight and a particle size of 89 nm (HPPS) was obtained.
  • XiranTM SZ 26080 (available from Polyscope Polymers) were also added. The pre-charge was heated to 85°C and stirred 16 h until the entire amount of XiranTM SZ 26080 was solubilized. Afterwards, at the same temperature (85°C), under stirring, the initiator feed consisting of 15.0 g of a 5% by weight sodium peroxodisulfate solution in water was started and fed into the reactor over 150 min. Concurrently the monomer feed consisting of 42 g of styrene, 18 g of n-butyl acrylate and 0.56 g of Terpinolene (90% by weight) was also started and fed over 120 min.
  • the initiator feed consisting of 15.0 g of a 5% by weight sodium peroxodisulfate solution in water was started and fed into the reactor over 150 min.
  • the monomer feed consisting of 42 g of styrene, 18 g of n-butyl acrylate and 0.56 g of Terpinolene (90% by weight) was also started and fed over 120 min.
  • the end of the monomer feed 10 g of demineralized water is added to the reactor and after the completion of the initiator feed the polymerization mixture was further stirred for 30 min.
  • the initiator feed consisting of 15.0 g of a 5% by weight sodium peroxodisulfate solution in water was started and fed into the reactor over 150 min.
  • the monomer feed consisting of 42 g of styrene, 18 g of n-butyl acrylate and 0.56 g of Terpinolene (90% by weight) was also started and fed over 120 min.
  • the end of the monomer feed 10 g of demineralized water is added to the reactor and after the completion of the initiator feed the polymerization mixture was further stirred for 30 min.
  • the initiator feed consisting of 15.0 g of a 5% by weight sodium peroxodisulfate solution in water was started and fed into the reactor over 150 min.
  • the monomer feed consisting of 42 g of styrene, 18 g of n-butyl acrylate and 0.56 g of Terpinolene (90% by weight) was also started and fed over 120 min.
  • the end of the monomer feed 10 g of demineralized water is added to the reactor and after the completion of the initiator feed the polymerization mixture was further stirred for 30 min.
  • the percentage data in the examples are percent by weight, unless evident otherwise from the context.
  • the particle sizes were determined by means of a high performance particle sizer (HPPS) from Malvern using a He-Ne laser (633 nm) at a scattering angle of 173°.
  • HPPS high performance particle sizer
  • aqueous solution of a degraded corn starch was adjusted to the desired concentration.
  • the dispersions of the examples and comparative example which were to be tested were then me- tered into the starch solution so that the size press liquor comprised 100 g/l of a degraded corn starch and 1 -3 g/l of the respective dispersion.
  • the mixture of starch solution and polymer dispersion was then applied by means of a size press to a paper having a grammage of 80 g/m, which was slightly presized in the pulp with AKD (alkyldiketene), at a temperature of 50° C.
  • the uptake of the preparation was in the region of about 45%.
  • the papers thus treated were dried by means of contact drying at 90°C, conditioned for 24 h at 50% atmospheric humidity and then subjected to the tests.
  • test paper used was a paper which was slightly presized in the pulp with AKD and had the following composition: fiber composition (80% of bleached birch sulfate pulp and 20% of bleached pine sulfate pulp) having a filler content of 19% (Hydrocarb 60ME from Omya)
  • the Cobb value according to DIN EN 20 535 was determined.
  • the water absorbing of the paper sheet in g/m after contact with water and a contact time of 60 s is defined as the Cobb6o value.
  • the T95 penetration measuring method was carried out on the formed paper sheets employing the EST 12 device, available from the company Emtec Electronic GmbH, in order to characterize the penetration behavior of liquids as they hit the paper surface, thereby simulating the properties of the paper during the printing process, such as during the application of printing inks onto paper or the ingress of water into the paper
  • the principle of the T95 measuring method can be described as follows: The test paper surface is brought into contact with the test liquid between the ultrasonic transmitter and the ultrasonic sensor. The part of the paper which is not tested is attached to the rear side of the device by means of a double-sided adhesive tape on a carrier plate. The ultrasonic sensor detects a waveform of the ultrasonic signal (increase and decrease) over time.
  • the so determined T95 value can be explained as follows. T stands for time, 95 stands for 95% of the maximum ultrasonic signal. This signal decreases after immersion of the paper in the test liquid as a result of the penetration of the liquid into the paper surface and hence as a conse- quence of the onset of air displacement by liquid over time.
  • the T95-value therefore represents the time after which the ultrasound signal is decreased to 95% of its maximum.
  • results demonstrate that dispersions prepared using a styrene, maleic anhydride polymer protective colloid of weight average molar mass within the claimed range exhibit improved surface sizing is achieved by comparison to analogous styrene, maleic anhydride polymer protective colloid of weight average molar mass of 5,000 g/mol. Further, the results also indicate that dispersions prepared with higher contents of the styrene, maleic anhydride polymer protective colloid, such as 40% and 50% by weight (active polymeric protective colloid on total monomer mixture content) exhibited better sizing results than compositions containing lower amounts of protective colloid.

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Abstract

Finely divided, anionic, aqueous polymer dispersions, processes for the preparation and use as sizes in papermaking. The present invention relates to a finely divided, anionic, aqueous polymer dispersion which is obtainable by emulsion polymerisation of a mixture of ethylenically unsaturated monomers in an aqueous medium containing a protective colloid, in which the mixture of ethylenically unsaturated monomers comprises: (a) from 40 to 90% by weight of at least one optionally substituted styrene; (b) from 10 to 60% by weight of at least one C1 to C12 alkyl (meth) acrylate; (c) from 0 to 5% by weight of at least one ethylenically unsaturated monomer comprising an acid group; and (d) from 0 to 20% by weight of at least one non-ionic, ethylenically unsaturated monomer differing from (a) or (b); the sum of (a) + (b) + (c) +(d) being 100% by weight, wherein the protective colloid is an at least partially hydrolysed polymer of (i) at least one optionally substituted styrene; and (ii) maleic anhydride, in which the polymer has a weight average molar mass of at least 8,000 g/mol. The invention also relates to a process for producing the finely divided, anionic, aqueous polymer dispersion and the use of the dispersions as sizing agents in the manufacture of paper, board or cardboard.

Description

Finely divided, anionic, aqueous polymer dispersions, processes for the preparation and use as sizes in papermaking.
Description
The invention relates to finely divided, aqueous polymer dispersions which are obtainable by emulsion polymerization of ethylenically unsaturated monomers in an aqueous medium containing a protective colloid, processes for the preparation of the dispersions and their use as sizes for paper, board and paperboard.
EP 0 276 770 B1 and EP 0 257 412 B2 disclose sizes based on finely divided, aqueous dispersions which are obtainable by copolymerization of ethylenically unsaturated monomers, such as acrylonitrile and (meth)acrylates and optionally up to 10% by weight of other monomers, such as styrene, by an emulsion polymerization in the presence of initiators comprising peroxide groups, in particular of redox initiators, and degraded starch. The use of chain-transfer agents, such as terpenes, is not disclosed in any of the documents.
WO 99/42490 A1 likewise discloses aqueous, finely divided polymer dispersions which are used for the surface sizing of paper, board and cardboard. The dispersions are obtainable by free radical emulsion polymerization of ethylenically unsaturated monomers in the presence of degraded starch having a number average molecular weight Mn of from 500 to 10,000. The monomers consist of (i) at least one optionally substituted styrene, (ii) at least one C C4-alkyl (meth)acrylate and (iii) optionally up to 10% by weight of other ethylenically unsaturated monomers. The polymerization is effected in the presence of a graft-linking, water-soluble redox sys- tern. The use of chain-transfer agents from the group consisting of the mercaptans is disclosed for adjusting the molecular weight.
WO 2002/14393 A1 discloses a process for the preparation of polymer dispersions which are used as sizes and coating materials. These polymer dispersions are obtainable by emulsion copolymerization of a monomer mixture comprising at least one (meth)acrylate of monohydric, saturated Cs-Cs-alcohols an at least one further ethylenically unsaturated monomer in the presence of a starch or of a starch derivative and of an initiator comprising peroxide groups. The emulsion polymerization is distinguished in that both the monomers and the initiator are metered in continuously, a first amount of initiator being metered in within a first feed period of from 5 to 60 minutes and a second amount of initiator which is smaller than the first amount of initiator being metered in within a second feed period of from 5 to 180 minutes. The use of chain- transfer agents is not disclosed.
Finely divided, starch-containing polymer dispersions as sizes for paper, board and cardboard are also disclosed in WO 2007/000419 A1 . These are obtainable by emulsion polymerization, in an aqueous medium, using redox initiators, of ethylenically unsaturated monomers comprising (i) at least one optionally substituted styrene, methyl methacrylate, acrylonitrile and/or methacry- lonitrile, (ii) at least one Ci-Ci2-alkyl (meth)acrylate and at least (iii) one ethylenically unsaturat- ed copolymerizable monomer in the presence of a degraded, cationic starch which has a molar mass Mw of from 1000 to 65 000 g/mol. The disclosure comprises a multiplicity of chain-transfer agents but the example according to the invention is carried out without a chain transfer agent. WO 2007/000420 A1 likewise discloses finely divided, aqueous, starch-containing polymer dispersions as sizes for paper, board and cardboard, which are obtainable by free radical emulsion polymerization of (i) at least one optionally substituted styrene, methyl methacrylate, acrylonitrile and/or methacrylonitrile, (ii) at least one Ci-C4-alkyl methacrylate, (iii) at least one Cs-C22-alkyl (meth)acrylate and (iv) optionally at least one other ethylenically copolymerizable monomer and (v) a degraded starch having a molar mass Mw of from 1000 to 65 000 in the presence of a chain-transfer agent. The description discloses a multiplicity of potential chain-transfer agents but tert-dodecyl merpatan is the preferred chain-transfer agent, which is also used in all examples. WO 201 1/039185 discloses a finely divided, starch containing polymer dispersions which are obtained by free radical emulsion polymerisation of ethylenically unsaturated monomers in the presence of at least one redox initiator and starch. The polymers are formed by polymerisation of at least one optionally substituted styrene, at least one Ci-Ci2-alkyl acrylate or methacrylate and optionally other ethylenically unsaturated monomer. The polymerisation employs at least one terpene-containing chain-transfer agent.
WO2013053840 teaches a finely divided, starch containing polymer dispersion obtainable by free radical emulsion polymerisation of a monomer mixture comprising less than 40% by weight, at least one optionally substituted styrene, and from greater than 60 to 100% by weight of at least one Ci-Ci2-alkyl acrylate or methacrylate and optionally other ethylenically unsaturated monomer. The polymerisation is carried out in at least one degraded starch, which has a molar mass Mw of from 1000 to 65,000 g/mol and in the presence of at least 0.01 % by weight, based on the monomers, of at least one chain transfer agent. The polymer dispersion optionally comprises an aluminium compound.
DE69725779 discloses latex dispersions, for instance resulting from the polymerisation of a mixture of hydrophobic monomers composed of styrene and of (meth) acrylic esters emulsion in an aqueous solution of water-soluble or water dispersible amphiphilic copolymer consisting of a combination of hydrophobic monomers and hydrophilic monomers bearing carboxylic acid func- tions, in the presence of claim radical initiator. The amphiphilic copolymer has a molecular mass of between 500 and 5000. Examples of amphiphilic copolymers include polymers of maleic anhydride and styrene. This disclosure describes the application of such latex dispersions to the bonding of papers. The objective of the present invention is to provide finely divided, anionic polymer aqueous dispersions which are effective surface sizing agents for paper, board and cardboard. A further objective of the present invention is to provide such a polymer dispersion in which a synthetic protective colloid is employed.
The present invention relates to a finely divided, anionic, aqueous polymer dispersion which is obtainable by emulsion polymerisation of a mixture of ethylenically unsaturated monomers in an aqueous medium containing a protective colloid, in which the mixture of ethylenically unsaturated monomers comprises: (a) from 40 to 90% by weight of at least one optionally substituted styrene;
(b) from 10 to 60% by weight of at least one Ci to C12 alkyl (meth) acrylate;
(c) from 0 to 5% by weight of at least one ethylenically unsaturated monomer comprising an acid group; and
(d) from 0 to 20% by weight of at least one non-ionic, ethylenically unsaturated monomer differ- ing from (a) or (b); the sum of (a) + (b) + (c) +(d) being 100% by weight, wherein the protective colloid is an at least partially hydrolysed polymer of
(i) at least one optionally substituted styrene; and
(ii) maleic anhydride, in which the polymer has a molar mass of at least 8,000 g/mol.
The aqueous polymer dispersions have been found to be very useful surface sizing agents for paper, board and cardboard.
The present invention also relates to a process for the preparation of a finely divided, anionic, aqueous polymer dispersion, in which a mixture of ethylenically unsaturated monomers comprising:
(a) from 40 to 90% by weight of at least one optionally substituted styrene;
(b) from 10 to 60% by weight of at least one Ci to C12 alkyl (meth) acrylate;
(c) from 0 to 5% by weight of at least one ethylenically unsaturated monomer comprising an acid group; and
(d) from 0 to 20% by weight of at least one non-ionic, ethylenically unsaturated monomer differing from (a) or (b); wherein the sum of (a) + (b) + (c) +(d) being 100% by weight, are polymerised by emulsion polymerisation in the presence of a redox initiator in an aqueous medium containing a protective colloid, wherein the protective colloid is an at least partially hydrolysed polymer of
(i) at least one optionally substituted styrene; and
(ii) maleic anhydride, in which the polymer has a weight average molar mass of at least 8,000 g/mol.
By an at least partially hydrolysed polymer we mean that at least some of the anhydride groups of the maleic anhydride repeating units have been hydrolysed to carboxylic acid functional groups or salts of carboxylic acid functional groups, such as ammonium salts or alkali metal salts, such as sodium or potassium. Suitably, from 30% to 100% of the anhydride groups have been hydrolysed to carboxylic acid groups or salts thereof. Generally from 50% to 100% of the anhydride groups have been hydrolysed. Often from 70 or 80% up to 90 or 100% of the anhydride groups have been hydrolysed.
The protective colloid may desirably be formed from
(i) from 50 to 95% by weight of at least one optionally substituted styrene; and
(ii) from 5 to 50% by weight of maleic anhydride.
Preferably the components of the protective colloid should be (i) from 55 to 90% by weight of at least one optionally substituted styrene; and (ii) from 10 to 45% by weight of maleic anhydride. More preferably component (i) should be from 60 to 85% or from 65 to 85%, most preferably from 65 to 80%, by weight of at least one optionally substituted styrene; and more preferably component (ii) should be from 15 to 40% or from 15 to 35%, most preferably from 20 to 35%, by weight of maleic anhydride.
Suitably the protective colloid may exhibit an acid number of up to 500 mg of potassium hydroxide per gram of polymer (mg KOH/g). Desirably the acid number may be from 100 to 500 mg KOH/g. Preferably, the acid number should be from 200 to 400 mg KOH/g and more preferably from 250 to 350 mg KOH/g. This may be determined by standard test method ASTM D 3644-06 (2012).
The protective colloid may have a glass transition temperature (Tg) of from 80°C to 200°C, such as from 100°C to 200°C, suitably from 1 10°C to 180°C, for instance from 120°C to 170°C. Glass transition temperature may be determined by the test method given according to ISO 3146.
The protective colloid is a polymer having a weight average molar mass of at least 8,000 g/mol, for instance from 8,000 to 500,000 g/mol. Suitably the weight average molar mass may be at least 9,000 g/mol, for instance from 9,000 to 400,000 g/mol. The weight average molar mass may be at least 10,000 g/mol, for instance from 10,000 to 300,000 g/mol. Desirably the weight average molar mass should be at least 20,000 g/mol, for instance from 20,000 to 200,000 g/mol, preferably in the range of from 50,000 to 150,000 g/mol. Weight average molar mass (Mw) may for instance be determined by standard techniques such as Gel Permeation Chromatography (GPC). Typically the GPC technique may use aqueous eluents and an apparatus combination from Agilent, for instance series 1 100.
In such a GPC technique the eluent may be THF (tetrahydrofuran) with 0.1 % trifluroacetic acid. The separation should take place in a separating column combination. Suitable column numbers are for instance 1621 , 1512 and 1626 (7.5 mm x 5 cm, 7.5 mm x 30 cm and 7.5 mm x 30 cm, respectively) adding as the separation material Plgel 10 μιτι Guard, Plgel 10 μιτι and Plgel 10 μιτι, respectively. Typically the flow rate can be in the region of 1 ml/min, and a column temperature of 35°C. A suitable calibration can be effective using Polystyrol standards from Poly- mer Laboratories with M = 580 and M = 6.870000.
Any suitable amount of the protective colloid may be used to prepare the polymer dispersion. Suitably the amount of protective colloid may be from 20% to 70 or 80% or more by weight of active protective colloid on the total active content of the monomer mixture. Often the amount of protective colloid should be at least 30% and preferably from 40% to 50%.
By active protective colloid we mean on the basis of 100% polymeric protective colloid. By total active content of the monomer mixture we mean 100% of the monomers in the monomer mixture.
Monomers of group (i) of the protective colloid and independently group (a) are optionally substituted styrenes. This group includes styrene and substituted styrenes, such as, for example, a- methylstyrene, styrenes halogenated on the ring, such as chlorostyrene, or Ci-C4-substituted styrenes, such as vinyltoluene. Of course, mixtures of optionally substituted styrenes can also be used. A preferably used monomer of this group is styrene, which is preferably used alone from this group.
The monomers of group (a) are present in an amount of from 40% to 90% by weight, preferably from 50% to 85% by weight, in the ethylenically unsaturated monomer mixture comprising (a), (b), (c) and (d). More preferably monomers of group (a) may be present in an amount of from 55% to 85% by weight, often from 60% to 80%, typically from 65% to 75% by weight.
Suitable monomers of group (b) are all esters of acrylic acid and of methacrylic acid which are derived from monohydric Ci-Ci2-alcohols, such as methyl acrylate, ethyl acrylate, ethyl methac- rylate, n-propyl acrylate, n-propyl methacrylate, isopropyl acrylate, isopropyl methacrylate, n- butyl acrylate, n-butyl methacrylate, isobutyl acrylate, isobutyl methacrylate, tert-butyl acrylate, tert-butyl methacrylate, sec-butyl acrylate, sec-butyl methacrylate, n-pentyl acrylate, n-pentyl methacrylate, neopentyl acrylate, neopentyl methacrylate, cyclohexyl acrylate, cyclohexyl meth- acrylate, 2-hexyl acrylate, 2-hexyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, n-octyl acrylate, n-octyl methacrylate, isooctyl acrylate, isooctyl methacrylate, decyl acrylate and decyl methacrylate, dodecyl acrylate, dodecyl methacrylate, 2-propylheptyl acrylate and 2-propylheptyl methacrylate. Preferably used monomers of this group are esters of acrylic acid and methacrylic acid with Ci-Cs-alcohols, such as methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, sec-butyl acrylate, isobutyl acrylate, tert-butyl acrylate, cyclohexyl acrylate, 2-ethylhexyl acrylate and 2-ethylhexyl methacrylate. The esters of acrylic acid with Ci-C4-alcohols, such as n-butyl acrylate, sec-butyl acrylate, isobutyl acrylate and tert-butyl acrylate are particularly preferred. Of these n-butyl acrylate and tert-butyl acrylate are examples of especially preferred monomers of this group.
According to the invention, at least one Ci-Ci2-alkyl acrylate and/or Ci-Ci2-alkyl methacrylate is used as a monomer of group (b), for example two or more of the abovementioned esters in any desired mixtures with one another. Preferably only one monomer from the group (b) is used as a monomer of the group and particularly preferably a monomer from the group consisting of the esters of acrylic acid with C C4-alcohols.
The monomers of group (b) are present in an amount of from 10 to 60% by weight, preferably from 15 to 50% by weight, in the ethylenically unsaturated monomer makes the comprising (a), (b), (c) and (d). More preferably the monomers of group (b) may be present in an amount of from 15 to 45% by weight, often from 20 to 40%, typically from 25 to 35% by weight.
The monomers of group (a) are present in an amount of from 40% to 90% by weight, preferably from 50% to 85% by weight, in the ethylenically unsaturated monomer mixture comprising (a), (b), (c) and (d). More preferably monomers of group (a) may be present in an amount of from 55% to 85% by weight, often from 60% to 80%, typically from 65% to 75% by weight.
Examples of monomers of group (c) are ethylenically unsaturated C3- to carboxylic acids, such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, ethacrylic acid, crotonic acid, monoesters of ethylenically unsaturated dicarboxylic acids, such as mono methyl maleate, mono methyl fumarate, mono ethyl maleate, mono ethyl fumarate, mono propyl male- ate, mono propyl, fumarate, mono-n-butyl maleate, mono-n-butyl fumarate, and styrene carboxylic acids and ethylenically unsaturated anhydrides, such as maleic anhydride and itaconic an- hydride. Depending on the water content of the solvent used in the first polymerisation stage, the anhydride group of monomers may be hydrolysed to carboxyl groups. In addition, monomers comprising sulpho- and/or phosphonic acid groups, such as 2-acrylamido-2-methyl propane sulphonic acid and vinyl phosphonic acid, are suitable as monomers (c). The monomers comprising acid groups can be used in the form of free acid groups and in the form of partly or completely neutralised with alkali metal bases, alkaline earth metal bases, ammonia and/or amines. For example, sodium hydroxide solution, potassium hydroxide solution, sodium carbonate, sodium bicarbonate, ammonia, trimethyl amine, triethyl amine, morpholine, ethanola- mine, diethanolamine, triethanolamine, or diethylene triamine is used for neutralising the acid groups of the monomers. It is of course possible to use two or more bases as neutralising agents. From this group of monomers, acrylic acid and methacrylic acid or mixtures of acrylic acid and methacrylic acid in any desired ratio are preferably used. The monomers of group (c) are present in an amount of from 0 to 5% by weight. Desirably these monomers may be included in an amount of from 0.5 to 5% by weight, suitably from 0.7 to 3.5% by weight, for instance between 1.5 and 2.5% by weight, such as around 2% by weight, in the monomer mixture comprising (a) to (d).
Component (d) of the monomer mixture used for the preparation of the above mentioned resin can, if appropriate, comprise non-ionic, ethylenically unsaturated monomers which are different from the monomers (a) or (b). Examples of such monomers are amides, such as, for example, acrylamide, methacrylamide, N-methyl acrylamide, N-methyl methacrylamide, N-ethyl acryla- mide and N-ethyl methacrylamide; vinyl compounds, such as vinyl acetate, vinyl propionate or vinylformamide; Ci3-3o alkyl (meth) acrylates.The alkyl moiety of the ester may contain between 13 and 30 carbon atoms, such as, for example, tridecyl acrylate, tridecyl methacrylate, tetradecyl acrylate, tetradecyl methacrylate, pentadecyl acrylate, pentadecyl methacrylate, hex- adecyl acrylate, hexadecyl methacrylate, heptadecyl acrylate, heptadecyl methacrylate, octade- cyl acrylate, such as n-octadecyl acrylate (stearyl acrylate), octadecyl methacrylate, such as n- octadecyl acrylate (stearyl acrylate), nonadecyl acrylate, nonadecyl methacrylate, cosyl acrylate, cosyl methacrylate, eicosyl acrylate, eicosyl methacrylate, docosyl acrylate, docosyl methacrylate, tricosyl acrylate, tricosyl methacrylate, tetracosyl acrylate, tetracosyl methacrylate or mixtures thereof. Alternatively the esters of acrylic acid or methacrylic acid having been prepared by reacting at least one ethylene oxide unit, for example hydroxyl ethyl methacrylate or diethylene glycol monomethacrylate. Other suitable monomers of this group include acryloni- trile and methacrylonitrile. It is of course also possible to use mixtures of said monomers. If the monomers group (d) are used, they are present in an amount of up to 20% by weight, in general in an amount of up to 10% by weight, for instance in an amount of up to 5% by weight, based on the total amount of monomers (a) to (d) in the monomer mixture. Desirably these monomers may be included in an amount of from 0.5 to 5% by weight, suitably from 0.7 to 3.5% by weight, in the monomer mixture comprising monomers (a) to (d) in the monomer mixture. The sum of the values in % by weight for the monomers (a) to (d) is always 100.
Preferred finely divided, anionic, aqueous polymer dispersions are those in which the monomer mixture employed in the emulsion polymerisation comprises (a) from 60 to 80% by weight of at least one optionally substituted styrene;
(b) from 20 to 40% by weight of at least one Ci to C4 alkyl (meth) acrylate; (c) from 0 to 5% by weight of at least one ethylenically unsaturated monomer comprising an acid group; and
(d) from 0 to 20% by weight of at least one non-ionic, ethylenically unsaturated monomer differing from (a) or (b), the sum of (a) + (b) + (c) +(d) being 100% by weight.
More preferred finely divided, anionic, aqueous polymer dispersions are those in which the monomer mixture employed in the emulsion polymerisation comprises
(a) from 60 to 80 % by weight of styrene;
(b) from 20 to 40% by weight of at least one of n-butyl acrylate and/or tert-butyl acrylate;
(c) from 0 to 5% by weight of acrylic acid and/or methacrylic acid;
(d) from 0 to 5% by weight of one or more of acrylamide, methacrylamide, N-methyl acrylamide, N-methyl methacrylamide, N-ethyl acrylamide and N-ethyl methacrylamide; vinyl acetate, vinyl propionate or vinylformamide; tridecyl acrylate, tridecyl methacrylate, tetradecyl acrylate, tetradecyl methacrylate,pentadecyl acrylate, pen- tadecyl methacrylate, hexadecyl acrylate, hexadecyl methacrylate, heptadecyl acrylate, heptadecyl methacrylate, octadecyl acrylate, such as n-octadecyl acrylate (stearyl acrylate), octadecyl methacrylate, such as n-octadecyl acrylate (stearyl acrylate), nonadecyl acrylate, nonadecyl methacrylate, cosyl acrylate, cosyl methacrylate, eicosyl acrylate, eicosyl methacrylate, docosyl acrylate, docosyl methacrylate, tricosyl acrylate, tricosyl methacrylate, tetracosyl acrylate, tetracosyl methacrylate; hydroxyl ethyl methacrylate or diethylene glycol monomethacrylate; acrylonitrile or methacrylonitrile.
A particularly preferred finely divided, anionic, aqueous polymer dispersion which is obtainable by emulsion polymerisation of a mixture of ethylenically unsaturated monomers in an aqueous medium containing a protective colloid, in which the mixture of ethylenically unsaturated monomers comprises:
(a) from 60 to 80 % by weight of styrene;
(b) from 20 to 40% by weight of at least one of n-butyl acrylate and/or tert-butyl acrylate;
(c) from 0 to 5% by weight of acrylic acid and/or methacrylic acid;
(d) from 0 to 5% by weight of one or more of acrylamide, methacrylamide, N-methyl acrylamide, N-methyl methacrylamide, N-ethyl acrylamide and N-ethyl methacrylamide; vinyl acetate, vinyl propionate or vinylformamide; tridecyl acrylate, tridecyl methacrylate, tetradecyl acrylate, tetradecyl methacrylate, pentadecyl acrylate, pen- tadecyl methacrylate, hexadecyl acrylate, hexadecyl methacrylate, heptadecyl acrylate, heptadecyl methacrylate, octadecyl acrylate, such as n-octadecyl acrylate (stearyl acrylate), octadecyl methacrylate, such as n-octadecyl acrylate (stearyl acrylate), nonadecyl acrylate, nonadecyl methacrylate, cosyl acrylate, cosyl methac- rylate, eicosyl acrylate, eicosyl methacrylate, docosyl acrylate, docosyl methacrylate, tricosyl acrylate, tricosyl methacrylate, tetracosyl acrylate, tetracosyl methacrylate; hydroxyl ethyl methacrylate or diethylene glycol monomethacrylate; acrylonitrile or methacrylonitrile; the sum of (a) + (b) + (c) +(d) being 100% by weight, wherein the protective colloid is an at least partially hydrolysed polymer of
(i) from 65 to 85% by weight of styrene; and
(ii) from 15 to 35% by weight of maleic anhydride, in which the polymer has a weight average molar mass of from 50,000 to 150,000 g/mol.
The polymerisation of the monomers (a), (b), if appropriate (c) and, if appropriate, (d) is effected by an emulsion polymerisation method, i.e. the monomer is to be polymerised are present in the polymerisation mixture as an aqueous emulsion. The protective colloids described above are used for stabilising the monomer emulsions.
The emulsion polymerisation is effected in general in a temperature range of from 40 to 150°C, preferably from 60 to 90°C. The emulsion polymerisation is conducted in the presence of second polymerisation initiators, which are preferably water-soluble. Initiators for the emulsion polymerisation may be used in any conventional amount. In general, from 0.2 to 5%, preferably from 0.4 to 3.5 %, more preferably 0.5 to 2.5% by weight of at least one initiator, based on the monomer is to be polymerised are used. Suitable second polymerisation initiators for use in the emulsion polymerisation are, for example, azo compounds, peroxides, hydroperoxides, inorganic peroxides and redox systems, such as combinations of hydrogen peroxide and ascorbic acid or tert-butyl hydroperoxide and ascorbic acid. The redox systems can moreover comprise metal cations, such as cerium, manganese or iron(ll) ions, for activation.
In the emulsion polymerisation, the monomers can either be metered directly into the initially taken mixture or they can be fed in the form of an aqueous emulsion or mini emulsion to the polymerisation batch. In order to emulsify the monomers in water, for example, a part of the aqueous solution and/or colloidal dispersion of the protective colloid described above, optionally diluted with water can be used as an emulsifier, or the monomers maybe emulsifier with the aid of customary non-ionic, anionic, cationic or amphoteric emulsifiers in water.
Customary emulsifiers may be used if desired. The amounts used are, for example, from 0.05 to 3% by weight and preferably in the range from 0.5 to 2% by weight, based on the combined weight of total monomer components (a) + (b) + (c) + (d) and protective colloid. Customary emulsifiers are described in detail in the literature, cf. for example M. Ash, I. Ash, Handbook of Industrial Surfactants, Third Edition, Synapse Information Resources Inc. Examples of customary emulsifiers include the reaction products of long chain monohydric alcohols (C10- to C22- alkanols) with from 4 to 80 mol of ethylene oxide and/or propylene oxide per mole of alcohol or ethoxylated phenols or alkoxylated alcohols esterified with sulphuric acid, which are generally used in the form neutralised with alkalis. Further customary emulsifiers are, for example, sodium alkane sulphonates, sodium alkyl sulphates, sodium dodecylbenzene sulphonates, sulpho- succinate esters, quaternary alkyl ammonium salts, alkyl benzyl ammonium salts, such as dime- thyl-Ci2 to Cis-alkyl benzyl ammonium chlorides, primary, secondary and tertiary fatty amine salts, quaternary amido amine compounds, alkylpyridinium salts, alkyl imidazolinium salts and alkyl oxazolinium salts. Preferably, however, no emulsifiers are used.
The metering of the monomers for carrying out emulsion polymerisation can be effected continuously or batchwise. With the use of a monomer mixture, the metering of the monomers can be effected as a mixture or separately or in a manner of a step or gradient procedure. The addition can be effected uniformly or non-uniformly, i.e. with a changing metering rate, over the metering period. By adding a portion of the monomer to the initially taken mixture comprising aqueous solution and/or aqueous colloidal dispersion of cationic or amphoteric protective colloid, metering by means of swelling procedure is possible. In a preferred embodiment of the present invention, the first polymerisation for the preparation of the resin and/or the emulsion polymerisation is/are carried out in the presence of polymerisation regulators. Suitable regulators are, for example, mercaptans, such as ethyl mercaptan, n- butyl mercaptan, tert-butyl mercaptan, n-dodecyl mercaptan or tetradodecyl mercaptan, thiogly- colic acid, 2-mercaptoethanol and 2-ethylhexyl thioglycolate, carbon tetrabromide, or isopropa- nol. Furthermore, suitable regulators are from the class consisting of the terpenes, preferably from the class consisting of the monocyclic terpenes and particularly preferably from a group consisting of the menthadienes. Among said regulators of the group consisting of menthadi- enes, terpinolene is very particularly preferred. If polymerisation regulators are used, the amounts of regulator are, For example, from 0.1 to 10% by weight, preferably for 0.3 to 5% by weight.
The pH of the reaction mixture is, for example, in the range from 6 to 12, in general from 7 to 10, in the polymerisation stage. The emulsion polymerisation may be carried out at a temperature higher than ambient (i.e. higher than 25°C). Typically the polymerisation may be carried out at temperatures from 70 to 95°C, suitably from 75 to 95°C, particularly from 80 to 90°C.
In order to remove the remaining monomers as substantially as possible from the polymer dis- persion, a post polymerisation is expediently carried out after the end of the emulsion polymerisation. For this purpose, for example, an initiator from the group consisting of hydroperoxide, peroxides, such as hydrogen peroxide, and/or azo initiators is added to the polymer dispersion after the end of the main polymerisation. Combining of the initiators with suitable reducing agents, such as, for example, ascorbic acid or sodium bisulphite, is also possible. Oil soluble, sparingly water-soluble initiators are preferably used, for example customary organic peroxides, such as dibenzoyl peroxide, di-tert-butyl peroxide, tert-butyl hydroperoxide, cumyl hydroperox- ide or biscyclohexyl peroxybicarbonate. For the post polymerisation, the reaction mixture is heated, for example, to a temperature which corresponds the temperature at which the main polymerisation was carried out or which is up to 20°C, preferably up to 10°C, lower. The main polymerisation is complete when the polymerisation initiator has been consumed or the monomer conversion is, for example, at least 98%, preferably at least 99.5%. For the post polymeri- sation, tert-butyl hydroperoxide is preferably used. The polymerisation is carried out, for example, in a temperature range of from 40 to 1 10°C, in general from 50 to 105°C.
In the emulsion polymerisation, finely divided, aqueous polymer dispersions which have anionic properties are obtained. The mean particle size of the dispersed particles is, for example 5 to 250 nm, preferably less than 120 nm, particularly preferably from 10 to 100 nm. The mean particle size can be determined by methods known to the person skilled in the art, such as, for example, laser correlation spectroscopy, ultracentrifuging or CHDF. A further measure of the particle size of the dispersed polymer particles is the LT value. For determining the LT value (light transmittance), the polymer dispersion to be investigated in each case is measured in 0.1 % strength by weight aqueous formulation in a cell having an edge length of 2.5 cm with light of wavelength 600 nm. The mean particle size can be calculated from the measured values of cf. B. Verner, M. Barta, B. Sedlacek, Tables of Scattering Functions For Spherical Particles, Prague 1976, Edice Marco, Rada D-DATA, SVAZEK D-1. The polymer concentration of the aqueous dispersions obtained in the emulsion polymerisation is, for example, from 10 to 40, preferably from 15 to 30% by weight.
The finely divided, anionic aqueous polymer dispersions described above are used as sizing agents for paper, board and cardboard. They can be used for the production of all paper varie- ties, for example of writing and printing papers and packaging paper is and papers for the packaging of liquids. They are suitable particular for the surface sizing of paper products. The dispersions according to the invention can be processed by all methods suitable in surface sizing, but they can also be used for internal sizing. For use as a sizing agent, the aqueous polymer dispersions are diluted by adding water, generally to a polymer content, for example, from 0.05 to 5% by weight. The amount of polymer dispersion depends on the desired degree of sizing of the papers or paper products to be finished. Such preparation solutions can, if appropriate, comprise further substances, for example starch, dyes, optical brighteners, biocides, paper strength agents, fixing agents, antifoams, retention aids and/or drainage aids. The size dispersion can be applied to paper, board or cardboard by means of a size press or other application units, such as film press, speed size or gate roll. The amount of polymer which is applied to the surface of the paper products is, for example, from 0.005 to 1.0 g/m2, preferably from 0.01 to 0.5 g/m2.
The polymer dispersions according to the invention exhibit an excellent sizing effect on papers produced with a variety of fibre types from unbleached softwood, unbleached deciduous wood, unbleached hardwood, bleached softwood, bleached deciduous wood, bleached hardwood, deinked fibres or mixtures of different fibre types. Furthermore, the dispersions according to the invention exhibit very good compatibility with the customary starches, for example potato starch, cornstarch, wheat starch, tapioca starch. Moreover, the dispersions according to the invention exhibit complete development of sizing after the production and drying of the paper web.
The invention is illustrated in more detail by reference to the following, non-limiting examples. Examples
Polymers Used as Protective Colloids in the Examples
Xiran™ SL26080N 10 - hydrolyzed styrene maleic anhydride copolymers as ammonium salt solutions (10% by weight in water), stated Mw = 80.000 g/mol, Tg = 160°C, acid number = 300 mg KOH/g. Maleic anhydride content is 26%.
Xiran™ SL26120N 10 - hydrolyzed styrene maleic anhydride copolymers as ammonium salt solutions (10% by weight in water), stated Mw = 120.000 g/mol, Tg = 160°C, acid number = 300 mg KOH/g. Maleic anhydride content is 26%.
Xiran™ SZ26080 - Styrene-maleic anhydride polymer granules, stated Mw = 80,000 g/mol, Tg = 160°C, acid number = 300 mg KOH/g. Maleic anhydride content is 26%.
Xiran™ SZ26120 - Styrene-maleic anhydride polymer granules, stated Mw = 120,000 g/mol, Tg = 160°C, acid number = 300 mg KOH/g. Maleic anhydride content is 26%.
Xiran™ SZ40005 - Styrene-maleic anhydride polymer granules, stated Mw = 5,000 g/mol, Tg = 130°C, acid number = 480 mg KOH/g. Maleic anhydride content is 42%. Xiran™ SZ25010 - Styrene-maleic anhydride polymer granules, stated Mw = 10,000 g/mol, Tg = 130°C, acid number = 285 mg KOH/g. Maleic anhydride content is 25%.
All of these products are available from Polyscope Polymers.
Example 1 : Dispersion 1
In a ground-joint 2 I flask equipped with stirrer and internal temperature measurement, 240 g of Xiran™ SL 26080N 10 (available from Polyscope Polymers) 10% by weight polymer solution (neutralized with ammonia) were added and the pre-charge was heated to 85°C. At 85°C, under stirring, the initiator feed consisting of 9.0 g of a 5% by weight sodium peroxodisulfate solution in water was started and fed into the reactor over 150 min. Concurrently the monomer feed consisting of 25.2 g of styrene, 10.80 g of n-butyl acrylate, 0.15 g of a 40% by weight Emulga- tor™ K 30 (available from Bayer) solution and 39 g of demineralized water was also started and fed over 120 min. At the end of the monomer feed 12 g of demineralized water is added to the reactor and after the completion of the initiator feed the polymerization mixture was further stirred for 30 min. Afterwards 1.2 g of a 10% by weight tert- butyl hydroperoxide solution were added to the reactor and polymerization mixture was then stirred for another 30 min. The polymerization mixture is cooled down to room temperature. A finely divided polymer dispersion having a solids content of 17.8% by weight and a particle size of 36 nm (HPPS) was obtained.
Example 2: Dispersion 2
In a ground-joint 2 I flask equipped with stirrer and internal temperature measurement, 240 g of Xiran™ SL 26120N 10 (available from Polyscope Polymers) 10% by weight polymer solution
(neutralized with ammonia) were added and the pre-charge was heated to 85°C. At 85°C, under stirring, the initiator feed consisting of 9.0 g of a 5% by weight sodium peroxodisulfate solution in water was started and fed into the reactor over 150 min. Concurrently the monomer feed consisting of 25.2 g of styrene, 10.80 g of n-butyl acrylate, 0.15 g of a 40% by weight Emulga- tor™ K 30 (available from Bayer) solution and 39 g of demineralized water was also started and fed over 120 min. At the end of the monomer feed 12 g of demineralized water is added to the reactor and after the completion of the initiator feed the polymerization mixture was further stirred for 30 min. Afterwards 1.2 g of a 10% by weight tert- butyl hydroperoxide solution were added to the reactor and polymerization mixture was then stirred for another 30 min. The polymerization mixture is cooled down to room temperature. A finely divided polymer dispersion having a solids content of 15.3% by weight and a particle size of 74 nm (HPPS) was obtained.
Example 3: Dispersion 3
In a ground-joint 2 I flask equipped with stirrer and internal temperature measurement, 180 g of Xiran™ SL 26080N 10 (available from Polyscope Polymers) 10% by weight polymer solution
(neutralized with ammonia) were added and the pre-charge was heated to 85°C. At 85°C, under stirring, 3.0 g of a 5% by weight sodium peroxodisulfate solution in water were added to the reactor and afterwards a feed consisting of 9.0 g of a 5% by weight sodium peroxodisulfate solution in water was started and fed into the reactor over 150 min. Concurrently the monomer feed consisting of 30.0 g of styrene, 12.0 g of n-butyl acrylate, 0.15 g of a 40% by weight Emulga- tor™ K 30 (available from Bayer) solution and 39 g of demineralized water was also started and fed over 120 min. At the end of the monomer feed 12 g of demineralized water is added to the reactor and after the completion of the initiator feed the polymerization mixture was further stirred for 30 min. Afterwards 1.2 g of a 10% by weight tert- butyl hydroperoxide solution were added to the reactor and polymerization mixture was then stirred for another 30 min. The polymerization mixture is cooled down to room temperature. A finely divided polymer dispersion having a solids content of 21.4% by weight and a particle size of 140 nm (HPPS) was obtained. Example 4: Dispersion 4
In a ground-joint 2 I flask equipped with stirrer and internal temperature measurement, 180 g of Xiran™ SL 26120N 10 (available from Polyscope Polymers) 10% by weight polymer solution (neutralized with ammonia) were added and the pre-charge was heated to 85°C. At 85°C, under stirring, 3.0 g of a 5% by weight sodium peroxodisulfate solution in water were added to the reactor and afterwards a feed consisting of 9.0 g of a 5% by weight sodium peroxodisulfate solution in water was started and fed into the reactor over 150 min. Concurrently the monomer feed consisting of 30.0 g of styrene, 12.0 g of n-butyl acrylate, 0.15 g of a 40% by weight Emulga- tor™ K 30 (available from Bayer) solution and 39 g of demineralized water was also started and fed over 120 min. At the end of the monomer feed 12 g of demineralized water is added to the reactor and after the completion of the initiator feed the polymerization mixture was further stirred for 30 min. Afterwards 1.2 g of a 10% by weight tert- butyl hydroperoxide solution were added to the reactor and polymerization mixture was then stirred for another 30 min. The polymerization mixture is cooled down to room temperature. A finely divided polymer dispersion having a solids content of 21.4% by weight and a particle size of 177 nm (HPPS) was obtained.
Example 5: Dispersion 5
In a ground-joint 2 I flask equipped with stirrer and internal temperature measurement, 240 g of Xiran™ SL 26080N 10 (available from Polyscope Polymers) 10% by weight polymer solution
(neutralized with ammonia) were added and the pre-charge was heated to 85°C. At 85°C, under stirring, the initiator feed consisting of 9.0 g of a 5% by weight sodium peroxodisulfate solution in water was started and fed into the reactor over 150 min. Concurrently, the monomer feed consisting of 25.2 g of styrene and 10.80 g of n-butyl acrylate was also started and fed over 120 min. At the end of the monomer feed 6 g of demineralized water is added to the reactor and after the completion of the initiator feed the polymerization mixture was further stirred for 30 min. Afterwards 1.2 g of a 10% by weight tert- butyl hydroperoxide solution were added to the reactor and polymerization mixture was then stirred for another 30 min. The polymerization mixture is cooled down to room temperature. A finely divided polymer dispersion having a solids content of 21.5% by weight and a particle size of 103 nm (HPPS) was obtained.
Example 6: Dispersion 6
In a ground-joint 2 I flask equipped with stirrer and internal temperature measurement, 240 g of Xiran™ SL 26120N 10 (available from Polyscope Polymers) 10% by weight polymer solution (neutralized with ammonia) were added and the pre-charge was heated to 85°C. At 85°C, under stirring, the initiator feed consisting of 9.0 g of a 5% by weight sodium peroxodisulfate solution in water was started and fed into the reactor over 150 min. Concurrently, the monomer feed consisting of 25.2 g of styrene and 10.80 g of n-butyl acrylate was also started and fed over 120 min. At the end of the monomer feed 6 g of demineralized water is added to the reactor and after the completion of the initiator feed the polymerization mixture was further stirred for 30 min. Afterwards 1.2 g of a 10% by weight tert- butyl hydroperoxide solution were added to the reactor and polymerization mixture was then stirred for another 30 min. The polymerization mix- ture is cooled down to room temperature. A finely divided polymer dispersion having a solids content of 20.7% by weight and a particle size of 153 nm (HPPS) was obtained.
Example 7: Dispersion 7
In a ground-joint 2 I flask equipped with stirrer and internal temperature measurement, 180 g of Xiran™ SL 26080N 10 (available from Polyscope Polymers) 10% by weight polymer solution (neutralized with ammonia) were added and the pre-charge was heated to 85°C. At 85°C, under stirring, the initiator feed consisting of 9.0 g of a 5% by weight sodium peroxodisulfate solution in water was started and fed into the reactor over 150 min. Concurrently the monomer feed consisting of 30 g of styrene and 12 g of n-butyl acrylate was also started and fed over 120 min. At the end of the monomer feed 6 g of demineralized water is added to the reactor and after the completion of the initiator feed the polymerization mixture was further stirred for 30 min. Afterwards 1.2 g of a 10% by weight tert- butyl hydroperoxide solution were added to the reactor and polymerization mixture was then stirred for another 30 min. The polymerization mixture is cooled down to room temperature. A finely divided polymer dispersion having a solids content of 26.7 % by weight and a particle size of 163 nm (HPPS) was obtained.
Example 8: Dispersion 8
In a ground-joint 2 I flask equipped with stirrer and internal temperature measurement, 180 g of Xiran™ SL 26120N 10 (available from Polyscope Polymers) 10% by weight polymer solution
(neutralized with ammonia) were added and the pre-charge was heated to 85°C. At 85°C, under stirring, the initiator feed consisting of 9.0 g of a 5% by weight sodium peroxodisulfate solution in water was started and fed into the reactor over 150 min. Concurrently the monomer feed consisting of 30 g of styrene and 12 g of n-butyl acrylate was also started and fed over 120 min. At the end of the monomer feed 6 g of demineralized water is added to the reactor and after the completion of the initiator feed the polymerization mixture was further stirred for 30 min. Afterwards 1.2 g of a 10% by weight tert- butyl hydroperoxide solution were added to the reactor and polymerization mixture was then stirred for another 30 min. The polymerization mixture is cooled down to room temperature. A finely divided polymer dispersion having a solids content of 26.4 % by weight and a particle size of 192 nm (HPPS) was obtained.
Example 9: Dispersion 9
In a ground-joint 2 I flask equipped with stirrer and internal temperature measurement, 285 g of demineralized water and 13.2 g of a 25% by weight ammonia solution were added, then under stirring 30 g Xiran™ SZ 26080 (available from Polyscope Polymers) were also added. The pre- charge was heated to 60°C and stirred 24 h until the entire amount of Xiran™ SZ 26080 was solubilized. Afterwards the pre-charge is heated to 85°C, under stirring, the initiator feed consisting of 26.2 g of a 4.7% by weight ammonium peroxodisulfate solution in water was started and fed into the reactor over 120 min. Concurrently the monomer feed consisting of 32.5 g of styrene and 37.5 g of n-butyl acrylate was also started and fed over 120 min. The polymerization mixture is cooled down to room temperature. A finely divided polymer dispersion having a solids content of 24.9% by weight and a particle size of 315 nm (HPPS) was obtained. Example 10: Dispersion 10
In a ground-joint 2 I flask equipped with stirrer and internal temperature measurement, 285 g of demineralized water and 13.2 g of a 25% by weight ammonia solution were added, then under stirring 30 g Xiran™ SZ 26120 (available from Polyscope Polymers) were also added. The pre- charge was heated to 60°C and stirred 24 h until the entire amount of Xiran™ SZ 26120 was solubilized. Afterwards the pre-charge is heated to 85°C, under stirring, the initiator feed consisting of 26.2 g of a 4.7% by weight ammonium peroxodisulfate solution in water was started and fed into the reactor over 120 min. Concurrently the monomer feed consisting of 32.5 g of styrene and 37.5 g of n-butyl acrylate was also started and fed over 120 min. The polymerization mixture is cooled down to room temperature. A finely divided polymer dispersion having a solids content of 24.9% by weight and a particle size of 391 nm (HPPS) was obtained.
Example 1 1 : Dispersion 1 1
In a ground-joint 2 I flask equipped with stirrer and internal temperature measurement, 285 g of demineralized water and 17.65 g of a 25% by weight ammonia solution were added, then under stirring 40 g Xiran™ SZ 26080 (available from Polyscope Polymers) were also added. The pre- charge was heated to 60°C and stirred 24 h until the entire amount of Xiran™ SZ 26080 was solubilized. Afterwards the pre-charge is heated to 85°C, under stirring, the initiator feed con- sisting of 26.2 g of a 4.7% by weight ammonium peroxodisulfate solution in water was started and fed into the reactor over 120 min. Concurrently the monomer feed consisting of 27.86 g of styrene and 32.14 g of n-butyl acrylate was also started and fed over 120 min. The polymerization mixture is cooled down to room temperature. A finely divided polymer dispersion having a solids content of 24.71 % by weight and a particle size of 101 nm (HPPS) was obtained.
Example 12: Dispersion 12 (GM 0197-0786)
In a ground-joint 2 I flask equipped with stirrer and internal temperature measurement, 285 g of demineralized water and 17.65 g of a 25% by weight ammonia solution were added, then under stirring 40 g Xiran™ SZ 26120 (available from Polyscope Polymers) were also added. The pre- charge was heated to 60°C and stirred 24 h until the entire amount of Xiran™ SZ 26120 was solubilized. Afterwards the pre-charge is heated to 85°C, under stirring, the initiator feed consisting of 26.2 g of a 4.7% by weight ammonium peroxodisulfate solution in water was started and fed into the reactor over 120 min. Concurrently the monomer feed consisting of 27.86 g of styrene and 32.14 g of n-butyl acrylate was also started and fed over 120 min. The polymeriza- tion mixture is cooled down to room temperature. A finely divided polymer dispersion having a solids content of 25% by weight and a particle size of 204 nm (HPPS) was obtained.
Example 13: Dispersion 13
In a ground-joint 2 I flask equipped with stirrer and internal temperature measurement, 120 g of Xiran™ SL 26080N 10 (available from Polyscope Polymers) 10% by weight polymer solution (neutralized with ammonia) and 54 g of demineralized water were added and the pre-charge was heated to 85°C. At 85°C, under stirring, the initiator feed consisting of 9.0 g of a 5% by weight sodium peroxodisulfate solution in water was started and fed into the reactor over 150 min. Concurrently the monomer feed consisting of 33 g of styrene and 15 g of n-butyl acrylate was also started and fed over 120 min. At the end of the monomer feed 6 g of demineralized water is added to the reactor and after the completion of the initiator feed the polymerization mixture was further stirred for 30 min. Afterwards 1.2 g of a 10% by weight tert- butyl hydroperoxide solution were added to the reactor and polymerization mixture was then stirred for another 30 min. The polymerization mixture is cooled down to room temperature. A finely divided polymer dispersion having a solids content of 26.3 % by weight and a particle size of 140 nm (HPPS) was obtained.
Example 14: Dispersion 14
In a ground-joint 2 I flask equipped with stirrer and internal temperature measurement, 120 g of Xiran™ SL 26120N 10 (available from Polyscope Polymers) 10% by weight polymer solution (neutralized with ammonia) and 54 g of demineralized water were added and the pre-charge was heated to 85°C. At 85°C, under stirring, the initiator feed consisting of 9.0 g of a 5% by weight sodium peroxodisulfate solution in water was started and fed into the reactor over 150 min. Concurrently the monomer feed consisting of 33 g of styrene and 15 g of n-butyl acrylate was also started and fed over 120 min. At the end of the monomer feed 6 g of demineralized water is added to the reactor and after the completion of the initiator feed the polymerization mixture was further stirred for 30 min. Afterwards 1.2 g of a 10% by weight tert- butyl hydroperoxide solution were added to the reactor and polymerization mixture was then stirred for another 30 min. The polymerization mixture is cooled down to room temperature. A finely divided polymer dispersion having a solids content of 26.0 % by weight and a particle size of 171 nm (HPPS) was obtained.
Example 15: Dispersion 15
In a ground-joint 2 I flask equipped with stirrer and internal temperature measurement, 120 g of Xiran™ SL 26120N 10 (available from Polyscope Polymers) 10% by weight polymer solution (neutralized with ammonia) and 54 g of demineralized water were added and the pre-charge was heated to 85°C. At 85°C, under stirring, the initiator feed consisting of 9.0 g of a 5% by weight sodium peroxodisulfate solution in water was started and fed into the reactor within 5 min. Concurrently the monomer feed consisting of 33 g of styrene and 15 g of n-butyl acrylate was also started and fed over 120 min. At the end of the monomer feed 6 g of demineralized water is added to the reactor and after the completion of the initiator feed the polymerization mixture was further stirred for 30 min. Afterwards 1.2 g of a 10% by weight tert- butyl hydroperoxide solution were added to the reactor and polymerization mixture was then stirred for another 30 min. The polymerization mixture is cooled down to room temperature. A finely divided polymer dispersion having a solids content of 26.0 % by weight and a particle size of 145 nm (HPPS) was obtained. Example 16: Dispersion 16
In a ground-joint 2 I flask equipped with stirrer and internal temperature measurement, 120 g of Xiran™ SL 26120N 10 (available from Polyscope Polymers) 10% by weight polymer solution (neutralized with ammonia), 54 g of demineralized water and 0.6 g of Lutensol™ AT 25 (availa- ble from BASF) 100% by weight were added and the pre-charge was heated to 85°C. At 85°C, under stirring, the initiator feed consisting of 9.0 g of a 5% by weight sodium peroxodisulfate solution in water was started and fed into the reactor over 150 min. Concurrently the monomer feed consisting of 33 g of styrene and 15 g of n-butyl acrylate was also started and fed over 120 min. At the end of the monomer feed 6 g of demineralized water is added to the reactor and after the completion of the initiator feed the polymerization mixture was further stirred for 30 min. Afterwards 1.2 g of a 10% by weight tert- butyl hydroperoxide solution were added to the reactor and polymerization mixture was then stirred for another 30 min. The polymerization mixture is cooled down to room temperature. A finely divided polymer dispersion having a solids content of 26.2 % by weight and a particle size of 259 nm (HPPS) was obtained.
Example 17: Dispersion 17
In a ground-joint 2 I flask equipped with stirrer and internal temperature measurement, 150 g of Xiran™ SL 26080N 10 (available from Polyscope Polymers) 10% by weight polymer solution (neutralized with ammonia) were added and the pre-charge was heated to 85°C. At 85°C, under stirring, the initiator feed consisting of 9.0 g of a 5% by weight sodium peroxodisulfate solution in water was started and fed into the reactor over 150 min. Concurrently the monomer feed consisting of 30 g of styrene, 15 g of n-butyl acrylate, 0.1 g of a 58% by weight Lumiten™ ISC (available from BASF) solution and 24 g of demineralized water was also started and fed over 120 min. At the end of the monomer feed 6 g of demineralized water is added to the reactor and after the completion of the initiator feed the polymerization mixture was further stirred for 30 min. Afterwards 1.2 g of a 10% by weight tert- butyl hydroperoxide solution were added to the reactor and polymerization mixture was then stirred for another 30 min. The polymerization mixture is cooled down to room temperature. A finely divided polymer dispersion having a solids content of 26.3% by weight and a particle size of 166 nm (HPPS) was obtained.
Example 18: Dispersion 18
In a ground-joint 2 I flask equipped with stirrer and internal temperature measurement, 150 g of Xiran™ SL 26120N 10 (available from Polyscope Polymers) 10% by weight polymer solution (neutralized with ammonia) were added and the pre-charge was heated to 85°C. At 85°C, under stirring, the initiator feed consisting of 9.0 g of a 5% by weight sodium peroxodisulfate solution in water was started and fed into the reactor over 150 min. Concurrently the monomer feed consisting of 30 g of styrene, 15 g of n-butyl acrylate, 0.1 g of a 58% by weight Lumiten™ ISC (available from BASF) solution and 24 g of demineralized water was also started and fed over 120 min. At the end of the monomer feed 6 g of demineralized water is added to the reactor and after the completion of the initiator feed the polymerization mixture was further stirred for 30 min. Afterwards 1.2 g of a 10% by weight tert- butyl hydroperoxide solution were added to the reactor and polymerization mixture was then stirred for another 30 min. The polymerization mix- ture is cooled down to room temperature. A finely divided polymer dispersion having a solids content of 27.1 % by weight and a particle size of 246 nm (HPPS) was obtained.
Example 19: Dispersion 19
In a ground-joint 2 I flask equipped with stirrer and internal temperature measurement, 150 g of Xiran™ SL 26080N 10 (available from Polyscope Polymers)10% by weight polymer solution (neutralized with ammonia) were added and the pre-charge was heated to 85°C. At 85°C, under stirring, the initiator feed consisting of 9.0 g of a 5% by weight sodium peroxodisulfate solution in water was started and fed into the reactor over 150 min. Concurrently the monomer feed consisting of 30 g of styrene, 15 g of n-butyl acrylate, 0.1 g of a 58% by weight Lumiten™ ISC (available from BASF) solution, 0.3 g of 2-ethylhexyl thioglycolate and 24 g of demineralized water was also started and fed over 120 min. At the end of the monomer feed 6 g of demineralized water is added to the reactor and after the completion of the initiator feed the polymerization mixture was further stirred for 30 min. Afterwards 1 .2 g of a 10% by weight tert- butyl hy- droperoxide solution were added to the reactor and polymerization mixture was then stirred for another 30 min. The polymerization mixture is cooled down to room temperature. A finely divided polymer dispersion having a solids content of 25.9% by weight and a particle size of 165 nm (HPPS) was obtained. Example 20: Dispersion 20
In a ground-joint 2 I flask equipped with stirrer and internal temperature measurement, 150 g of Xiran™ SL 26120N 10 (available from Polyscope Polymers) 10% by weight polymer solution (neutralized with ammonia) were added and the pre-charge was heated to 85°C. At 85°C, under stirring, the initiator feed consisting of 9.0 g of a 5% by weight sodium peroxodisulfate solution in water was started and fed into the reactor over 150 min. Concurrently the monomer feed consisting of 30 g of styrene, 15 g of n-butyl acrylate, 0.1 g of a 58% by weight Lumiten™ ISC (available from BASF) solution, 0.3 g of 2-ethylhexyl thioglycolate and 24 g of demineralized water was also started and fed over 120 min. At the end of the monomer feed 6 g of demineralized water is added to the reactor and after the completion of the initiator feed the polymeriza- tion mixture was further stirred for 30 min. Afterwards 1 .2 g of a 10% by weight tert- butyl hydroperoxide solution were added to the reactor and polymerization mixture was then stirred for another 30 min. The polymerization mixture is cooled down to room temperature. A finely divided polymer dispersion having a solids content of 26.8% by weight and a particle size of 254 nm (HPPS) was obtained.
Example 21 : Dispersion 21
In a ground-joint 2 I flask equipped with stirrer and internal temperature measurement, 210 g of Xiran™ SL 26080N 10 (available from Polyscope Polymers) 10% by weight polymer solution (neutralized with ammonia) were added and the pre-charge was heated to 85°C. At 85°C, under stirring, the initiator feed consisting of 9.0 g of a 5% by weight sodium peroxodisulfate solution in water was started and fed into the reactor over 150 min. Concurrently the monomer feed consisting of 27 g of styrene, 12 g of n-butyl acrylate, 0.1 g of a 58% by weight Lumiten™ ISC (available from BASF) solution and 24 g of demineralized water was also started and fed over 120 min. At the end of the monomer feed 6 g of demineralized water is added to the reactor and after the completion of the initiator feed the polymerization mixture was further stirred for 30 min. Afterwards 1.2 g of a 10% by weight tert- butyl hydroperoxide solution were added to the reactor and polymerization mixture was then stirred for another 30 min. The polymerization mixture is cooled down to room temperature. A finely divided polymer dispersion having a solids content of 20.2% by weight and a particle size of 123 nm (HPPS) was obtained.
Example 22: Dispersion 22
In a ground-joint 2 I flask equipped with stirrer and internal temperature measurement, 210 g of Xiran™ SL 2621 ON 10 (available from Polyscope Polymers) 10% by weight polymer solution (neutralized with ammonia) were added and the pre-charge was heated to 85°C. At 85°C, under stirring, the initiator feed consisting of 9.0 g of a 5% by weight sodium peroxodisulfate solution in water was started and fed into the reactor over 150 min. Concurrently the monomer feed consisting of 27 g of styrene, 12 g of n-butyl acrylate, 0.1 g of a 58% by weight Lumiten™ ISC (available from BASF) solution and 24 g of demineralized water was also started and fed over 120 min. At the end of the monomer feed 6 g of demineralized water is added to the reactor and after the completion of the initiator feed the polymerization mixture was further stirred for 30 min. Afterwards 1.2 g of a 10% by weight tert- butyl hydroperoxide solution were added to the reactor and polymerization mixture was then stirred for another 30 min. The polymerization mixture is cooled down to room temperature. A finely divided polymer dispersion having a solids content of 21.1 % by weight and a particle size of 158 nm (HPPS) was obtained.
Example 23: Dispersion 23
In a ground-joint 2 I flask equipped with stirrer and internal temperature measurement, 266.6 g of Xiran™ SL 26080N 10 (available from Polyscope Polymers) 10% by weight polymer solution (neutralized with ammonia) were added and the pre-charge was heated to 85°C. At 85°C, under stirring, the initiator feed consisting of 9.0 g of a 5% by weight sodium peroxodisulfate solution in water was started and fed into the reactor over 150 min. Concurrently the monomer feed consisting of 25.2 g of styrene and 10.8 g of n-butyl acrylate was also started and fed over 120 min. At the end of the monomer feed 6 g of demineralized water is added to the reactor and after the completion of the initiator feed the polymerization mixture was further stirred for 30 min. Afterwards 1.2 g of a 10% by weight tert- butyl hydroperoxide solution were added to the reactor and polymerization mixture was then stirred for another 30 min. The polymerization mix- ture is cooled down to room temperature. A finely divided polymer dispersion having a solids content of 20.1 % by weight and a particle size of 128 nm (HPPS) was obtained.
Example 24: Dispersion 24
In a ground-joint 2 I flask equipped with stirrer and internal temperature measurement, 266.6 g of Xiran™ SL 26120N 10 (available from Polyscope Polymers) 10% by weight polymer solution (neutralized with ammonia) were added and the pre-charge was heated to 85°C. At 85°C, under stirring, the initiator feed consisting of 9.0 g of a 5% by weight sodium peroxodisulfate solution in water was started and fed into the reactor over 150 min. Concurrently the monomer feed consisting of 25.2 g of styrene and 10.8 g of n-butyl acrylate was also started and fed over 120 min. At the end of the monomer feed 6 g of demineralized water is added to the reactor and after the completion of the initiator feed the polymerization mixture was further stirred for 30 min. Afterwards 1.2 g of a 10% by weight tert- butyl hydroperoxide solution were added to the reactor and polymerization mixture was then stirred for another 30 min. The polymerization mixture is cooled down to room temperature. A finely divided polymer dispersion having a solids content of 19.5 % by weight and a particle size of 181 nm (HPPS) was obtained. Example 25: Dispersion 25
In a ground-joint 2 I flask equipped with stirrer and internal temperature measurement, 333.3 g of Xiran™ SL 26080N 10 (available from Polyscope Polymers) 10% by weight polymer solution (neutralized with ammonia) were added and the pre-charge was heated to 85°C. At 85°C, under stirring, the initiator feed consisting of 9.0 g of a 5% by weight sodium peroxodisulfate solution in water was started and fed into the reactor over 150 min. Concurrently the monomer feed consisting of 21 .0 g of styrene and 9.0 g of n-butyl acrylate was also started and fed over 120 min. At the end of the monomer feed 6 g of demineralized water is added to the reactor and after the completion of the initiator feed the polymerization mixture was further stirred for 30 min. Afterwards 1.2 g of a 10% by weight tert- butyl hydroperoxide solution were added to the reactor and polymerization mixture was then stirred for another 30 min. The polymerization mixture is cooled down to room temperature. A finely divided polymer dispersion having a solids content of 15.6 % by weight and a particle size of 101.4 nm (HPPS) was obtained.
Example 26: Dispersion 26
In a ground-joint 2 I flask equipped with stirrer and internal temperature measurement, 333.3 g of Xiran™ SL 26120N 10 (available from Polyscope Polymers) 10% by weight polymer solution (neutralized with ammonia) were added and the pre-charge was heated to 85°C. At 85°C, under stirring, the initiator feed consisting of 9.0 g of a 5% by weight sodium peroxodisulfate solution in water was started and fed into the reactor over 150 min. Concurrently the monomer feed consisting of 21 .0 g of styrene and 9.0 g of n-butyl acrylate was also started and fed over 120 min. At the end of the monomer feed 6 g of demineralized water is added to the reactor and after the completion of the initiator feed the polymerization mixture was further stirred for 30 min. Afterwards 1.2 g of a 10% by weight tert- butyl hydroperoxide solution were added to the reactor and polymerization mixture was then stirred for another 30 min. The polymerization mix- ture is cooled down to room temperature. A finely divided polymer dispersion having a solids content of 16.2 % by weight and a particle size of 144 nm (HPPS) was obtained.
Example 27: Dispersion 27
In a ground-joint 2 I flask equipped with stirrer and internal temperature measurement, 266.7 g of Xiran™ SL 26080N 10 (available from Polyscope Polymers) 10% by weight polymer solution (neutralized with ammonia) were added and the pre-charge was heated to 85°C. At 85°C, under stirring, the initiator feed consisting of 9.0 g of a 5% by weight sodium peroxodisulfate solution in water was started and fed into the reactor over 150 min. Concurrently the monomer feed consisting of 24.0 g of styrene, 1 1 .4 g of n-butyl acrylate and 0.6 g of acrylic acid was also started and fed over 120 min. At the end of the monomer feed 6 g of demineralized water is added to the reactor and after the completion of the initiator feed the polymerization mixture was further stirred for 30 min. Afterwards 1.2 g of a 10% by weight tert- butyl hydroperoxide solution were added to the reactor and polymerization mixture was then stirred for another 30 min. The polymerization mixture is cooled down to room temperature. A finely divided polymer dispersion having a solids content of 18 % by weight and a particle size of 204 nm (HPPS) was obtained. Example 28: Dispersion 28
In a ground-joint 2 I flask equipped with stirrer and internal temperature measurement, 266.7 g of Xiran™ SL 26120N 10 (available from Polyscope Polymers) 10% by weight polymer solution (neutralized with ammonia) were added and the pre-charge was heated to 85°C. At 85°C, under stirring, the initiator feed consisting of 9.0 g of a 5% by weight sodium peroxodisulfate solution in water was started and fed into the reactor over 150 min. Concurrently the monomer feed consisting of 24.0 g of styrene, 1 1 .4 g of n-butyl acrylate and 0.6 g of acrylic acid was also started and fed over 120 min. At the end of the monomer feed 6 g of demineralized water is added to the reactor and after the completion of the initiator feed the polymerization mixture was further stirred for 30 min. Afterwards 1.2 g of a 10% by weight tert- butyl hydroperoxide solution were added to the reactor and polymerization mixture was then stirred for another 30 min. The polymerization mixture is cooled down to room temperature. A finely divided polymer dispersion having a solids content of 18.1 % by weight and a particle size of 186 nm (HPPS) was obtained.
Example 29: Dispersion 29
In a ground-joint 2 I flask equipped with stirrer and internal temperature measurement, 266.6 g of Xiran™ SL 26080N 10 (available from Polyscope Polymers) 10% by weight polymer solution (neutralized with ammonia) were added and the pre-charge was heated to 85°C. At 85°C, under stirring, the initiator feed consisting of 9.0 g of a 5% by weight sodium peroxodisulfate solution in water was started and fed into the reactor over 150 min. Concurrently the monomer feed consisting of 18.0 g of styrene and 18.0 g of n-butyl acrylate was also started and fed over 120 min. At the end of the monomer feed 6 g of demineralized water is added to the reactor and after the completion of the initiator feed the polymerization mixture was further stirred for 30 min. Afterwards 1.2 g of a 10% by weight tert- butyl hydroperoxide solution were added to the reactor and polymerization mixture was then stirred for another 30 min. The polymerization mix- ture is cooled down to room temperature. A finely divided polymer dispersion having a solids content of 19.0 % by weight and a particle size of 136 nm (HPPS) was obtained.
Example 30: Dispersion 30
In a ground-joint 2 I flask equipped with stirrer and internal temperature measurement, 266.6 g of Xiran™ SL 26120N 10 (available from Polyscope Polymers) 10% by weight polymer solution (neutralized with ammonia) were added and the pre-charge was heated to 85°C. At 85°C, under stirring, the initiator feed consisting of 9.0 g of a 5% by weight sodium peroxodisulfate solution in water was started and fed into the reactor over 150 min. Concurrently the monomer feed consisting of 18.0 g of styrene and 18.0 g of n-butyl acrylate was also started and fed over 120 min. At the end of the monomer feed 6 g of demineralized water is added to the reactor and after the completion of the initiator feed the polymerization mixture was further stirred for 30 min. Afterwards 1.2 g of a 10% by weight tert- butyl hydroperoxide solution were added to the reactor and polymerization mixture was then stirred for another 30 min. The polymerization mixture is cooled down to room temperature. A finely divided polymer dispersion having a solids content of 19.0 % by weight and a particle size of 190 nm (HPPS) was obtained. Example 31 : Dispersion 31
In a ground-joint 2 I flask equipped with stirrer and internal temperature measurement, 350 g of demineralized water, 16 g of a 25% by weight ammonia solution and 1 g of Afranil™ T
(defoamer) (available from BASF) 100% by weight, were added, then under stirring 40 g Xiran™ SZ 26080 (available from Polyscope Polymers) were also added. The pre-charge was heated to 85°C and stirred 16 h until the entire amount of Xiran™ SZ 26080 was solubilized. Afterwards, at the same temperature (85°C), under stirring, the initiator feed consisting of 9.0 g of a 5% by weight sodium peroxodisulfate solution in water was started and fed into the reactor over 150 min. Concurrently the monomer feed consisting of 42 g of styrene, 18 g of n-butyl acrylate and 0.56 g of Terpinolene (90% by weight) was also started and fed over 120 min. At the end of the monomer feed 10 g of demineralized water is added to the reactor and after the completion of the initiator feed the polymerization mixture was further stirred for 30 min. Afterwards 2 g of a 10% by weight tert- butyl hydroperoxide solution were added to the reactor and polymerization mixture was then stirred for another 30 min. The polymerization mixture is cooled down to room temperature. A finely divided polymer dispersion having a solids content of 21 .8% by weight and a particle size of 89 nm (HPPS) was obtained.
Example 32: Dispersion 32
In a ground-joint 2 I flask equipped with stirrer and internal temperature measurement, 340 g of demineralized water, 16 g of a 25% by weight ammonia solution and 1 g of Afranil™ T
(defoamer) (available from BASF) 100% by weight, were added, then under stirring 40 g
Xiran™ SZ 26080 (available from Polyscope Polymers) were also added. The pre-charge was heated to 85°C and stirred 16 h until the entire amount of Xiran™ SZ 26080 was solubilized. Afterwards, at the same temperature (85°C), under stirring, the initiator feed consisting of 15.0 g of a 5% by weight sodium peroxodisulfate solution in water was started and fed into the reactor over 150 min. Concurrently the monomer feed consisting of 42 g of styrene, 18 g of n-butyl acrylate and 0.56 g of Terpinolene (90% by weight) was also started and fed over 120 min. At the end of the monomer feed 10 g of demineralized water is added to the reactor and after the completion of the initiator feed the polymerization mixture was further stirred for 30 min. Afterwards 2 g of a 10% by weight tert- butyl hydroperoxide solution were added to the reactor and immediately a feed consisting of 12.5 g of 10% by weight ascorbic acid solution were started and fed over 15 min into the reactor and polymerization mixture was then stirred for another 15 min. The polymerization mixture is cooled down to room temperature. A finely divided polymer dispersion having a solids content of 21 .6% by weight and a particle size of 96 nm (HPPS) was obtained.
Example 33: Dispersion 33
In a ground-joint 2 I flask equipped with stirrer and internal temperature measurement, 340 g of demineralized water, 16 g of a 25% by weight ammonia solution, 2.0 g of Lutensol™ AT 25 (available from BASF) 1 g of Afranil™ T (defoamer) (available from BASF) 100% by weight, were added, then under stirring 40 g Xiran™ SZ 26080 (available from Polyscope Polymers) were also added. The pre-charge was heated to 85°C and stirred 16 h until the entire amount of Xiran™ SZ 26080 was solubilized. Afterwards, at the same temperature (85°C), under stirring, the initiator feed consisting of 15.0 g of a 5% by weight sodium peroxodisulfate solution in water was started and fed into the reactor over 150 min. Concurrently the monomer feed consisting of 42 g of styrene, 18 g of n-butyl acrylate and 0.56 g of Terpinolene (90% by weight) was also started and fed over 120 min. At the end of the monomer feed 10 g of demineralized water is added to the reactor and after the completion of the initiator feed the polymerization mixture was further stirred for 30 min. Afterwards 2 g of a 10% by weight tert- butyl hydroperoxide solution were added to the reactor and immediately a feed consisting of 25 g of 10% by weight ascorbic acid solution were started and fed over 15 min into the reactor and polymerization mixture was then stirred for another 15 min. The polymerization mixture is cooled down to room temperature. A finely divided polymer dispersion having a solids content of 21 .6% by weight and a particle size of 106 nm (HPPS) was obtained.
Example 34: Dispersion 34
In a ground-joint 2 I flask equipped with stirrer and internal temperature measurement, 350 g of demineralized water, 16 g of a 25% by weight ammonia solution and 0.5 g of Afranil™ T
(defoamer) (available from BASF) 100% by weight, were added, then under stirring 40 g Xiran™ SZ 26080 (available from Polyscope Polymers) were also added. The pre-charge was heated to 85°C and stirred 12 h until the entire amount of Xiran™ SZ 26080 was solubilized. Afterwards, at the same temperature (85°C), under stirring, the initiator feed consisting of 15.0 g of a 5% by weight sodium peroxodisulfate solution in water was started and fed into the reactor over 150 min. Concurrently the monomer feed consisting of 42 g of styrene and 18 g of n-butyl acrylate was also started and fed over 120 min. At the end of the monomer feed 10 g of demineralized water is added to the reactor and after the completion of the initiator feed the polymerization mixture was further stirred for 30 min. Afterwards 2 g of a 10% by weight tert- butyl hy- droperoxide solution were added to the reactor and polymerization mixture was then stirred for another 30 min. The polymerization mixture is cooled down to room temperature. A finely divided polymer dispersion having a solids content of 21.4% by weight and a particle size of 149 nm (HPPS) was obtained.
Comparative example 1 : Dispersion 35
In a ground-joint 2 I flask equipped with stirrer and internal temperature measurement, 275 g of demineralized water and 21.0 g of a 25% by weight ammonia solution were added, then under stirring 30 g Xiran™ SZ 40005 (available from Polyscope Polymers) were also added. The pre- charge was heated to 60°C and stirred 24 h until the entire amount of Xiran™ SZ 40005 was solubilized. Afterwards the pre-charge is heated to 85°C, under stirring, the initiator feed consisting of 26.2 g of a 4.7% by weight ammonium peroxodisulfate solution in water was started and fed into the reactor over 120 min. Concurrently the monomer feed consisting of 32.5 g of styrene and 37.5 g of n-butyl acrylate was also started and fed over 120 min. The polymerization mixture is cooled down to room temperature. A finely divided polymer dispersion having a solids content of 25% by weight and a particle size of 136 nm (HPPS) was obtained. Comparative example 2: Dispersion 36
In a ground-joint 2 I flask equipped with stirrer and internal temperature measurement, 270 g of demineralized water and 28.0 g of a 25% by weight ammonia solution were added, then under stirring 40 g Xiran™ SZ 40005 (available from Polyscope Polymers) were also added. The pre- charge was heated to 60°C and stirred 24 h until the entire amount of Xiran™ SZ 40005 was solubilized. Afterwards the pre-charge is heated to 85°C, under stirring, the initiator feed consisting of 26.2 g of a 4.7% by weight ammonium peroxodisulfate solution in water was started and fed into the reactor over 120 min. Concurrently the monomer feed consisting of 27.86 g of styrene and 32.14 g of n-butyl acrylate was also started and fed over 120 min. The polymerization mixture is cooled down to room temperature. A finely divided polymer dispersion having a solids content of 25% by weight and a particle size of 83 nm (H PPS) was obtained.
Example 35: Dispersion 37
In a ground-joint 2 I flask equipped with stirrer and internal temperature measurement, 285 g of demineralized water and 12.16 g of a 25% by weight ammonia solution were added, then under stirring 30 g Xiran™ SZ 25010 (available from Polyscope Polymers) were also added. The pre- charge was heated to 60°C and stirred 24 h until the entire amount of Xiran™ SZ 25010 was solubilized. Afterwards the pre-charge is heated to 85°C, under stirring, the initiator feed consisting of 26.2 g of a 4.7% by weight ammonium peroxodisulfate solution in water was started and fed into the reactor over 120 min. Concurrently the monomer feed consisting of 32.5 g of styrene and 37.5 g of n-butyl acrylate was also started and fed over 120 min. The polymerization mixture is cooled down to room temperature. A finely divided polymer dispersion having a solids content of 25% by weight and a particle size of 42 nm (H PPS) was obtained.
Example 36: Dispersion 38
In a ground-joint 2 I flask equipped with stirrer and internal temperature measurement, 285 g of demineralized water and 16.8 g of a 25% by weight ammonia solution were added, then under stirring 40 g Xiran™ SZ 25010 (available from Polyscope Polymers) were also added. The pre- charge was heated to 60°C and stirred 24 h until the entire amount of Xiran™ SZ 25010 was solubilized. Afterwards the pre-charge is heated to 85°C, under stirring, the initiator feed con- sisting of 26.2 g of a 4.7% by weight ammonium peroxodisulfate solution in water was started and fed into the reactor over 120 min. Concurrently the monomer feed consisting of 27.86 g of styrene and 32.14 g of n-butyl acrylate was also started and fed over 120 min. The polymeriza- tion mixture is cooled down to room temperature. A finely divided polymer dispersion having a solids content of 25% by weight and a particle size of 60 nm (H PPS) was obtained.
Comparative example 3: Dispersion 39
In a ground-joint 2 I flask equipped with stirrer and internal temperature measurement, 340 g of demineralized water, 25.64 g of a 25% by weight ammonia solution and 1.0 g of Afranil™ T (defoamer) (available from BASF) 100% by weight, were added, then under stirring 40 g Xiran™ SZ 40005 (available from Polyscope Polymers) were also added. The pre-charge was heated to 85°C and stirred 12 h until the entire amount of Xiran™ SZ 40005 was solubilized. Afterwards, at the same temperature (85°C), under stirring, the initiator feed consisting of 15.0 g of a 5% by weight sodium peroxodisulfate solution in water was started and fed into the reactor over 150 min. Concurrently the monomer feed consisting of 42 g of styrene, 18 g of n-butyl acrylate and 0.56 g of Terpinolene (90% by weight) was also started and fed over 120 min. At the end of the monomer feed 10 g of demineralized water is added to the reactor and after the completion of the initiator feed the polymerization mixture was further stirred for 30 min. Afterwards 2 g of a 10% by weight tert- butyl hydroperoxide solution were added to the reactor and polymerization mixture was then stirred for another 30 min. The polymerization mixture is cooled down to room temperature. A finely divided polymer dispersion having a solids content of 20.5 % by weight and a particle size of 154 nm (HPPS) was obtained.
Example 37: Dispersion 40
In a ground-joint 2 I flask equipped with stirrer and internal temperature measurement, 350 g of demineralized water, 15.2 g of a 25% by weight ammonia solution and 1 .0 g of Afranil™ T (defoamer) (available from BASF) 100% by weight, were added, then under stirring 40 g Xiran™ SZ 25010 (available from Polyscope Polymers) were also added. The pre-charge was heated to 85°C and stirred 12 h until the entire amount of Xiran™ SZ 25010 was solubilized. Afterwards, at the same temperature (85°C), under stirring, the initiator feed consisting of 15.0 g of a 5% by weight sodium peroxodisulfate solution in water was started and fed into the reactor over 150 min. Concurrently the monomer feed consisting of 42 g of styrene, 18 g of n-butyl acrylate and 0.56 g of Terpinolene (90% by weight) was also started and fed over 120 min. At the end of the monomer feed 10 g of demineralized water is added to the reactor and after the completion of the initiator feed the polymerization mixture was further stirred for 30 min. Afterwards 2 g of a 10% by weight tert- butyl hydroperoxide solution were added to the reactor and polymerization mixture was then stirred for another 30 min. The polymerization mixture is cooled down to room temperature. A finely divided polymer dispersion having a solids content of 21 .3 % by weight and a particle size of 61 nm (HPPS) was obtained.
Information Applicable to All Examples The percentage data in the examples are percent by weight, unless evident otherwise from the context. The particle sizes were determined by means of a high performance particle sizer (HPPS) from Malvern using a He-Ne laser (633 nm) at a scattering angle of 173°.
Use of the Respective Dispersions from Each of the Examples as Sizing Agents for Paper
Application test:
An aqueous solution of a degraded corn starch was adjusted to the desired concentration. The dispersions of the examples and comparative example which were to be tested were then me- tered into the starch solution so that the size press liquor comprised 100 g/l of a degraded corn starch and 1 -3 g/l of the respective dispersion. The mixture of starch solution and polymer dispersion was then applied by means of a size press to a paper having a grammage of 80 g/m, which was slightly presized in the pulp with AKD (alkyldiketene), at a temperature of 50° C. The uptake of the preparation was in the region of about 45%. Thereafter, the papers thus treated were dried by means of contact drying at 90°C, conditioned for 24 h at 50% atmospheric humidity and then subjected to the tests.
The test paper used was a paper which was slightly presized in the pulp with AKD and had the following composition: fiber composition (80% of bleached birch sulfate pulp and 20% of bleached pine sulfate pulp) having a filler content of 19% (Hydrocarb 60ME from Omya)
For determining the degree of sizing of the surface-sized papers, the Cobb value according to DIN EN 20 535 was determined. The water absorbing of the paper sheet in g/m after contact with water and a contact time of 60 s is defined as the Cobb6o value. The lower the Cobb value, the better is the sizing effect of the dispersion used. Cobb 60 values - woodfree unsized; speed 4 m/min, 1 application cycle; drying temperature 120°C
The T95 penetration measuring method was carried out on the formed paper sheets employing the EST 12 device, available from the company Emtec Electronic GmbH, in order to characterize the penetration behavior of liquids as they hit the paper surface, thereby simulating the properties of the paper during the printing process, such as during the application of printing inks onto paper or the ingress of water into the paper
The principle of the T95 measuring method can be described as follows: The test paper surface is brought into contact with the test liquid between the ultrasonic transmitter and the ultrasonic sensor. The part of the paper which is not tested is attached to the rear side of the device by means of a double-sided adhesive tape on a carrier plate. The ultrasonic sensor detects a waveform of the ultrasonic signal (increase and decrease) over time. The so determined T95 value can be explained as follows. T stands for time, 95 stands for 95% of the maximum ultrasonic signal. This signal decreases after immersion of the paper in the test liquid as a result of the penetration of the liquid into the paper surface and hence as a conse- quence of the onset of air displacement by liquid over time. The T95-value therefore represents the time after which the ultrasound signal is decreased to 95% of its maximum.
The higher the T95 value is, the better is the sizing effect of the dispersion used.
The results are shown in tables 1 , 2 and 3.
Table 1
Cobb6o-Value T95 Xiran content
[g/m2] [s] (percentage)
Applied amount
1 2 3 1 2 3
[g/l solid]
Basoplast 400 DS 84 78 34 0.68 2.1 2.5 -
Basoplast 420 G 86 43 29 0.99 2.66 2.49 -
Example 1 53 29 23 1.45 1.96 2.1 1 40
Example 2 45 25 23 1.6 2.1 2.24 40
Example 3 82 30 24 1 2.06 2.09 30
Example 4 84 40 33 0.76 1.75 1 .89 30
Example 5 58 30 27.5 2.1 2.69 2.85 40
Example 6 59.5 30 28.5 1.86 2.54 3.17 40
Example 7 98.5 35.5 29.5 1.06 2.17 2.42 30
Example 8 89.5 43 32.5 0.79 2.1 2.26 30
Figure imgf000030_0001
Table 3
Figure imgf000031_0001
The results demonstrate that dispersions prepared using a styrene, maleic anhydride polymer protective colloid of weight average molar mass within the claimed range exhibit improved surface sizing is achieved by comparison to analogous styrene, maleic anhydride polymer protective colloid of weight average molar mass of 5,000 g/mol. Further, the results also indicate that dispersions prepared with higher contents of the styrene, maleic anhydride polymer protective colloid, such as 40% and 50% by weight (active polymeric protective colloid on total monomer mixture content) exhibited better sizing results than compositions containing lower amounts of protective colloid.

Claims

Claims
1. A finely divided, anionic, aqueous polymer dispersion which is obtainable by emulsion polymerisation of a mixture of ethylenically unsaturated monomers in an aqueous medium con- taining a protective colloid, in which the mixture of ethylenically unsaturated monomers comprises:
(a) from 40 to 90% by weight of at least one optionally substituted styrene;
(b) from 10 to 60% by weight of at least one Ci to C12 alkyl (meth) acrylate;
(c) from 0 to 5% by weight of at least one ethylenically unsaturated monomer comprising an acid group; and
(d) from 0 to 20% by weight of at least one non-ionic, ethylenically unsaturated monomer differing from (a) or (b); the sum of (a) + (b) + (c) +(d) being 100% by weight, wherein the protective colloid is an at least partially hydrolysed polymer of (i) at least one optionally substituted styrene; and
(ii) maleic anhydride, in which the polymer has a weight average molar mass of at least 8,000 g/mol.
2. The finely divided, anionic, aqueous polymer dispersion according to claim 1 in which the protective colloid is formed from
(i) from 60 to 90% by weight of at least one optionally substituted styrene; and
(ii) from 10 to 40% by weight of maleic anhydride.
3. The finely divided, anionic, aqueous polymer dispersion according to claim 1 or claim 2 in which the protective colloid is a polymer having a weight average molar mass of at least 20,000 g/mol, preferably in the range of from 50,000 to 150,000 g/mol.
4. The finely divided, anionic, aqueous polymer dispersion according to any preceding claim in which the monomer mixture employed in the emulsion polymerisation comprises
(a) from 60 to 80% by weight of at least one optionally substituted styrene;
(b) from 20 to 40% by weight of at least one Ci to C4 alkyl (meth) acrylate;
(c) from 0 to 5% by weight of at least one ethylenically unsaturated monomer comprising an acid group; and (d) from 0 to 20% by weight of at least one non-ionic, ethylenically unsaturated monomer differing from (a) or (b), the sum of (a) + (b) + (c) +(d) being 100% by weight.
5. The finely divided, anionic, aqueous polymer dispersion according to any preceding claim in which the emulsion polymerisation is carried out in the presence of from 0.01 to 10% by weight of at least one polymerisation regulator.
6. The finely divided, anionic, aqueous polymer dispersion according to any preceding claim in which the polymerisation regulator is a monocyclic monoterpene, preferably terpinolene.
7. A process for the preparation of a finely divided, anionic, aqueous polymer dispersion according to any of claims 1 to 6, in which a mixture of ethylenically unsaturated monomers comprising:
(a) from 40 to 90% by weight of at least one optionally substituted styrene;
(b) from 10 to 60% by weight of at least one Ci to C12 alkyl (meth) acrylate;
(c) from 0 to 5% by weight of at least one ethylenically unsaturated monomer comprising an acid group; and
(d) from 0 to 20% by weight of at least one non-ionic, ethylenically unsaturated monomer differing from (a) or (b); wherein the sum of (a) + (b) + (c) +(d) being 100% by weight, are polymerised by emulsion polymerisation in the presence of a redox initiator in an aqueous medium containing a protective colloid, wherein the protective colloid is an at least partially hydrolysed polymer of
(i) at least one optionally substituted styrene; and
(ii) maleic anhydride, in which the polymer has a weight average molar mass of at least 8,000 g/mol.
8. The process according to claim 7 in which the protective colloid is formed from
(i) from 60 to 90% by weight of at least one optionally substituted styrene; and
(ii) from 10 to 40% by weight of maleic anhydride.
9. The process according to claim 7 or claim 8 in which the protective colloid is a polymer having a weight average molar mass of at least 20,000 g/mol, preferably in the range of from 50,000 to 150,000 g/mol.
10. The process according to any of claims 7 to 9, in which the monomer mixture employed in the emulsion polymerisation comprises
(a) from 60 to 80% by weight of at least one optionally substituted styrene;
(b) from 20 to 40% by weight of at least one Ci to C4 alkyl (meth) acrylate;
(c) from 0 to 5% by weight of at least one ethylenically unsaturated monomer comprising an acid group; and
(d) from 0 to 20% by weight of at least one non-ionic, ethylenically unsaturated monomer differing from (a) or (b), the sum of (a) + (b) + (c) +(d) being 100% by weight.
1 1. The process according to any of claims 7 to 10, in which the emulsion polymerisation is carried out in the presence of from 0.01 to 10% by weight of at least one polymerisation regulator.
12. The process according to any of claims 7 to 1 1 , in which the polymerisation regulator is a monocyclic monoterpene, preferably terpinolene.
13. The process according to any of claims 7 to 12, in which an initiator from the group consist- ing of hydrogen peroxide, peroxides, hydroperoxides and/or azo initiators is added to the polymer dispersion after the end of the main polymerisation, and a post-polymerisation is carried out.
14. The process according to claim 13, in which tertiary butyl hydroperoxide, is added to the polymer dispersion for post polymerisation.
15. The use of the finely divided, anionic, aqueous polymer dispersion according to claims 1 to 6 or obtainable by the process according to claims 7 to 14 as a size for paper, board and cardboard.
PCT/IB2016/054704 2015-08-06 2016-08-04 Finely divided, anionic, aqueous polymer dispersions, processes for the preparation and use as sizes in papermaking WO2017021917A1 (en)

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH05501575A (en) * 1989-11-25 1993-03-25 ヘンケル・コマンディットゲゼルシャフト・アウフ・アクチェン Method for producing stable polymer dispersions using amphoteric polymers as stabilizers
JPH06172408A (en) * 1992-12-07 1994-06-21 Showa Highpolymer Co Ltd Production of emulsion having super water resistance
CN1177602A (en) * 1996-05-31 1998-04-01 埃尔夫阿托化学有限公司 Bonding of paper using latex-dispersions of copolymers made of hydrophobic monomers/polymers of styrene/maleic anhydride type
CN102300940A (en) * 2009-02-02 2011-12-28 瓦克化学股份公司 Cross-linkable, in water redispersible polymer powder compound
CN103415539A (en) * 2010-11-25 2013-11-27 巴斯夫欧洲公司 Finely divided, cationic or amphoteric, aqueous polymer dispersions, process for their preparation, their use, cationic or amphoteric protective colloids and their preparation

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH05501575A (en) * 1989-11-25 1993-03-25 ヘンケル・コマンディットゲゼルシャフト・アウフ・アクチェン Method for producing stable polymer dispersions using amphoteric polymers as stabilizers
JPH06172408A (en) * 1992-12-07 1994-06-21 Showa Highpolymer Co Ltd Production of emulsion having super water resistance
CN1177602A (en) * 1996-05-31 1998-04-01 埃尔夫阿托化学有限公司 Bonding of paper using latex-dispersions of copolymers made of hydrophobic monomers/polymers of styrene/maleic anhydride type
CN102300940A (en) * 2009-02-02 2011-12-28 瓦克化学股份公司 Cross-linkable, in water redispersible polymer powder compound
CN103415539A (en) * 2010-11-25 2013-11-27 巴斯夫欧洲公司 Finely divided, cationic or amphoteric, aqueous polymer dispersions, process for their preparation, their use, cationic or amphoteric protective colloids and their preparation

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