EP0819193B1 - Paper sizing agent mixtures - Google Patents

Abstract

Paper sizing agent mixtures of: (A) finely divided aqueous dispersions of C14 to C22 alkyl diketenes obtainable by dispersing the alkyl diketenes in water in the presence of cationic starch with an amylopectin content of at least 95 wt.%, and (B) finely divided aqueous polymer dispersions forming a paper sizing agent, process for producing the paper sizing agent mixtures by mixing th e components (A) and (B) and the use of the paper sizing agent mixtures as mass and surface sizing agents for paper, pasteboard and cardboard.

Description

(A) feinteiligen, wäßrigen Dispersionen von C₁₄- bis C₂₂-Alkyldiketenen, die durch Dispergieren der Alkyldiketene in Wasser in Gegenwart von kationischer Stärke erhältlich sind und

(B) Polymerdispersionen, die ein Leimungsmittel für Papier sind,

The invention relates to paper sizing mixtures

(A) finely divided, aqueous dispersions of C ₁₄ -C ₂₂ -alkyldiketenes which can be obtained by dispersing the alkyldiketenes in water in the presence of cationic starch and

(B) polymer dispersions that are a sizing agent for paper,

Process for the preparation of the above-mentioned paper sizing agent mixtures by mixing components (A) and (B) or by emulsifying C ₁₄ -C ₂₂ -alkyldiketenes in a mixture of aqueous suspensions of cationic starches and finely divided, aqueous polymer dispersions which are a sizing agent for paper , at temperatures of at least 70 ° C, and the use of paper sizing mixtures as mass and surface sizing agents for paper, cardboard and cardboard.

The above-mentioned paper sizing mixtures as well as their Production and use are known from WO-A 94/05855.

The aqueous dispersions indicated under (A) and (B) belong the state of the art. For example, from the US-A-3 130 118 aqueous alkyl diketene dispersions known by dispersing the alkyldiketenes in water in the presence of cationic starch are available. Fatty alkyl diketene dispersions, which in the presence of cationic condensates and where appropriate, cationic starch are produced, for example known from DE-A-30 00 502 and DE-A-33 16 179. Stabilized aqueous alkyldiketene dispersions are known from EP-B-0 437 764 known, the up to 40 wt .-% alkyl diketene can contain dispersed and as a stabilizer in addition to cationic Starch long chain fatty acid esters and / or urethanes contain.

Aqueous polymer dispersions that are a sizing agent for paper are described, for example, in the following references: JP-A-58/115 196, EP-B-0 257 412, EP-B-0 267 770, EP-B-0 051 144, EP-A-0 058 313 and EP-A-0 150 003. These References are cited in the above-mentioned WO-A-94/05855.

From DE-A-3 235 529, paper sizing mixtures are known which consist of emulsions of C ₁₄ -C ₂₀ -alkyldiketenes and finely divided polymer dispersions containing copolymerized nitrogen-containing monomers, which are known from EP-B-0 051 144 mentioned above. These sizing mixtures are prepared by combining a fatty alkyl diketene emulsion with an aqueous, finely divided polymer dispersion or are only formed in the paper stock before sheet formation by simultaneously adding the emulsified fatty alkyl diketene and the finely divided aqueous dispersion to the paper stock and thoroughly mixing the system. Mixtures which can only be obtained by stirring cationic, finely divided aqueous polymer dispersions into fatty alkyl diketene dispersions are not sufficiently stable in storage.

From EP-B-0 353 212 sizing agents are in the form of storage-stable aqueous Emulsions known that a hydrophobic cellulose-reactive sizing agent, e.g. Fatty alkyl diketene, and a cationic starch with an amylopectin content of at least 85% and a degree of cationization (D.S.) from 0.045 to 0.40. The share of Amylopectin in the cationic starch is preferably 98 until 100 %. Starch which is preferably used is waxy corn starch.

Furthermore, the emulsions can also accelerate sizing Synthetic resins, or other properties of the sizing agent containing synthetic resins.

EP-B-0 369 328 discloses aqueous, stable alkyldiketene dispersions, which contain up to 30% by weight of ketene dimer. More essential Components of these alkyldiketene dispersions are cationic Starch, preferably cationic waxy maize starches, Aluminum sulfate, carboxylic acids with 1 to 10 carbon atoms, and Sulfonates such as lignin sulfonic acid or condensation products from Formaldehyde and naphthalene sulfonic acids.

The present invention has for its object an improved Paper sizing agents containing fatty alkyl diketenes to provide that when used as a mass sizing agent there is sufficient instant sizing and that does not affect the whiteness of the paper and an improved shear and compared to the known mixtures Has storage stability.

(A) feinteiligen, wäßrigen Dispersionen von C₁₄- bis C₂₂-Alkyldiketenen, die durch Dispergieren der Alkyldiketene in Wasser in Gegenwart von kationischer Stärke erhältlich sind und

(B) feinteiligen, wäßrigen Polymerdispersionen, die ein Leimungsmittel für Papier sind,

wenn der Amylopektingehalt der kationischen Stärke der Komponente (A) mindestens 95 % beträgt. Der Amylopektingehalt der kationischen Stärke beträgt vorzugsweise 98 bis 100 %. Geeignete Stärken dieser Art sind vorzugsweise kationische Wachsmaisstärken.The object is achieved according to the invention with paper size mixtures

(A) finely divided, aqueous dispersions of C ₁₄ -C ₂₂ -alkyldiketenes which can be obtained by dispersing the alkyldiketenes in water in the presence of cationic starch and

(B) finely divided, aqueous polymer dispersions which are a sizing agent for paper,

if the amylopectin content of the cationic starch of component (A) is at least 95%. The amylopectin content of the cationic starch is preferably 98 to 100%. Suitable starches of this type are preferably cationic waxy maize starches.

(A) feinteiligen, wäßrigen Dispersionen von C₁₄- bis C₂₂-Alkyldiketenen, die durch Dispergieren der Alkyldiketene in Wasser in Gegenwart von kationischer Stärke erhältlich sind, mit

(B) feinteiligen, wäßrigen Polymerdispersionen, die ein Leimungsmittel für Papier sind,

oder durch Emulgieren von C₁₄- bis C₂₂-Alkyldiketenen in einer Mischung aus wäßrigen Suspensionen von kationischen Stärken von feinteiligen, wäßrigen Polymerdispersionen, die ein Leimungsmittel für Papier sind, bei Temperaturen von mindestens 70°C. Das Verfahren ist dadurch gekennzeichnet, daß der Amylopektingehalt der kationischen Stärken mindestens 95 % beträgt.The invention also relates to a method for producing paper size mixtures by mixing

(A) finely divided, aqueous dispersions of C ₁₄ -C ₂₂ -alkyldiketenes, which can be obtained by dispersing the alkyldiketenes in water in the presence of cationic starch

(B) finely divided, aqueous polymer dispersions which are a sizing agent for paper,

or by emulsifying C ₁₄ to C ₂₂ alkyl diketenes in a mixture of aqueous suspensions of cationic starches of finely divided, aqueous polymer dispersions which are a sizing agent for paper at temperatures of at least 70 ° C. The process is characterized in that the amylopectin content of the cationic starches is at least 95%.

The invention also relates to the use of those described above Paper sizing mixtures as mass and surface sizing agents for paper, cardboard and cardboard.

For the preparation of component (A) one starts from C ₁₄ to C ₂₂ alkyl diketenes or from mixtures of such alkyl diketenes. Alkyldiketenes are known and commercially available. They are produced, for example, from the corresponding carboxylic acid chlorides by splitting off hydrogen chloride with tertiary amines. Suitable fatty alkyldiketenes are, for example, tetradecyldiketene, hexadecyldiketene, octadecyldiketene, docosyldiketene, palmityldiketene, stearyldiketene and behenyldiketene. Also suitable are diketenes with different alkyl groups, for example stearyl palmityldiketene, behenylstearyldiketene, behenyloleyldiketene or palmitylbehenyldiketene. Stearyldiketene, palmityldiketene, behenyldiketene or mixtures of stearyldiketene and palmityldiketene or mixtures of behenyldiketene or mixtures of behenyldiketene or mixtures are preferably used. The diketenes are present in the aqueous emulsions in concentrations of 5 to 60, preferably 10 to 40,% by weight.

The alkyldiketenes become more cationic in water in the presence of Starch emulsifies, which according to the invention have an amylopectin content of has at least 95, preferably 98 to 100%. Such strengths can, for example, by fractionating more common native Starches or through breeding measures from such plants which produce practically pure amylopectin starch, see. Günther Tegge, Starch and Starch Derivatives, Hamburg, Bers-Verlag 1984, pages 157 to 160. Cationic strengths with an amylopectin content of at least 95, preferably 98 to 100% by weight are available on the market. The amylopectin strengths have a branched structure and a high degree of polymerization. The molecular weights (number average) are, for example 200 million to 400 million. For waxy corn starch with an amylopectin content of 99 to 100% are in the Literature average molecular weights (number average) of about Stated 320 million. According to the invention, cationized Starches are used whose amylopectin content is at least 95%. The degree of cationization of starch is determined by means of the degree of substitution (D.S.) specified. This value gives the number of the cationic groups per monosaccharide unit in the cationic Strength again. The degree of substitution (D.S. value) of the cationic starches is, for example, 0.010 to 0.150. In in most cases it is below 0.045, e.g. point the possible cationic starches preferably one Degree of substitution (D.S.) from 0.020 to 0.040.

oder mit Dialkylaminoalkylchloriden der Formel

oder vorzugsweise mit epoxidgruppenhaltigen quartären Ammoniumsalzen der Formel

oder der entsprechenden Halogenhydrine der Formel

The starch containing at least 95% by weight of amylopectin is cationized by introducing groups which contain tertiary or quaternary nitrogen atoms, for example by reacting the starches in question, in particular waxy maize starch, with dialkylaminoalkyl epoxides of the formula

or with dialkylaminoalkyl chlorides of the formula

or preferably with quaternary ammonium salts of the formula containing epoxide groups

or the corresponding halohydrins of the formula

In the formulas I to IV, the substituents R ² , R ³ and R ^{4 represent} alkyl, aryl, aralkyl or hydrogen, R ^{1 represents} an alkylene group, for example C ₁ -C ₆ alkylene. Examples of such compounds are 3-chloro-2-hydroxypropyltrimethylammonium chloride or glycidyltrimethylammonium chloride.

In addition to the preferred preferred waxy maize starch wax potato starch, wax wheat starch or mixtures the mentioned strengths in cationized form.

The cationic starches with amylopectin contents of at least 95% are contained in the aqueous alkyldiketene dispersion in an amount of 0.5 to 5, preferably 1 to 3% by weight. The finely divided, aqueous dispersions of component (A) are usually prepared by first converting the starches containing at least 95% amylopectin to a water-soluble form. This can be done, for example, with the aid of oxidative or hydrolytic degradation in the presence of acids or simply by heating the cationic starches. The starch is preferably digested in a jet cooker at temperatures in the range from 100 to 150.degree. At least one C ₁₄ -C ₂₂ -alkyldiketene is then dispersed in the aqueous solution of the cationic starch with a minimum amylopectin content of at least 95% by weight at temperatures above 70 ° C., for example in the range from 70 to 85 ° C. The alkyl diketenes dispersion is then cooled so that the alkyl diketenes are in solid form. Finely divided aqueous alkyldiketene dispersions having an average particle diameter of, for example, 0.5 to 2.5, preferably 0.8 to 1.5 μm are obtained. The alkyldiketenes can optionally also be dispersed in water in the presence of ligninsulfonic acid, condensates of formaldehyde and naphthalenesulfonic acids, polymers containing styrene sulfonic acid groups or the compounds containing alkali metal and / or ammonium salts of the aforementioned sulfonic acid groups. These substances act as dispersants and stabilize the resulting alkyl diketene dispersions. If these dispersants are used in the preparation of the alkyldiketene dispersions, the amounts used are, for example, 0.01 to 1, preferably 0.02 to 0.2% by weight, based on the alkyldiketene dispersion.

In the preparation of the alkyldiketene emulsions, in addition to the cationic wax strengths, other customary protective colloids which have hitherto been used in the production of alkyldiketene emulsions may also be used, for example water-soluble cellulose ethers, polyacrylamides, polyvinyl alcohols, polyvinylpyrrolidones, polyamides, polyamidoamines and mixtures of these mentioned connections. Component (A) may optionally contain further substances which are customary in alkyldiketene dispersions, for example C ₁ -C ₁₀ -carboxylic acids, for example formic acid, acetic acid or propionic acid. If they are contained in the alkyldiketene dispersions, the acids are used in amounts of 0.01 to 1% by weight. The alkyldiketene dispersions may also contain conventional biocides, which can be used in amounts of up to 1% by weight.

(a) Styrol, Acrylnitril und/oder Methacrylnitril,

(b) Acrylsäure- und/oder Methacrylsäureester von C₁- bis C₁₈-Alkoholen und/oder Vinylester von gesättigtem C₂- bis C₄-Carbonsauren und gegebenenfalls

(c) anderen monoethylenisch ungesättigten copolymerisierbaren Monomeren

in wäßriger Lösung in Gegenwart von 1 Gew.-Teil eines Lösungscopolymerisats aus

(1) Di-C₁- bis C₄-Alkylamino-C₂- bis C₄-Altyl(meth)acrylaten, die gegebenenfalls protoniert oder quaterniert sein können,

(2) nichtionischen, hydrophoben, ethylenisch ungesättigten Monomeren, bei diesen Monomeren, wenn sie für sich alleine polymerisiert werden, hydrophobe Polymerisate bilden und gegebenenfalls

(3) monoethylenisch ungesättigten C₃- bis C₅-Carbonsäuren oder ihren Anhydriden, wobei das Molverhältnis von (1) : (2) : (3) = 1 : 2,5 bis 10 : 0 bis 1,5 beträgt, copolymerisiert.

Component (B) of the paper size mixtures according to the invention consists of finely divided, aqueous polymer dispersions which are a size for paper. Such polymer dispersions are known, for example, from EP-B-0 051 144, EP-B-0 257 412, EP-B-0 276 770, EP-B-0 058 313 and EP-B-0 150 003 . Such polymer dispersions which act as paper sizing agents can be obtained, for example, by mixing 1 to 32 parts by weight of a mixture

(a) styrene, acrylonitrile and / or methacrylonitrile,

(b) Acrylic acid and / or methacrylic acid esters of C ₁ to C ₁₈ alcohols and / or vinyl esters of saturated C ₂ to C ₄ carboxylic acids and optionally

(c) other monoethylenically unsaturated copolymerizable monomers

in aqueous solution in the presence of 1 part by weight of a solution copolymer

(1) di-C ₁ to C ₄ alkylamino C ₂ to C ₄ allyl (meth) acrylates, which may optionally be protonated or quaternized,

(2) nonionic, hydrophobic, ethylenically unsaturated monomers, in the case of these monomers, if they are polymerized on their own, form hydrophobic polymers and, if appropriate

(3) monoethylenically unsaturated C ₃ to C ₅ carboxylic acids or their anhydrides, the molar ratio of (1): (2): (3) = 1: 2.5 to 10: 0 to 1.5 being copolymerized.

A solution copolymer is first prepared in which the monomers of groups (1) and (2) and optionally (3) are copolymerized in a water-miscible organic solvent. Suitable solvents are, for example, C ₁ to C ₃ carboxylic acids, such as formic acid, acetic acid and propionic acid, or C ₁ to C ₄ alcohols, such as methanol, ethanol, n-propanol or isopropanol, and ketones such as acetone. The group (1) monomers used are preferably dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, dimethylaminopropyl methacrylate and dimethylaminopropyl acrylate. The monomers of group (1) are preferably used in protonated or quaternized form. Suitable quaternizing agents are, for example, methyl chloride, dimethyl sulfate or benzyl chloride.

The group (2) monomers used are nonionic, hydrophobic, ethylenically unsaturated compounds which, when polymerized on their own, form hydrophobic polymers. These include, for example, styrene, methylstyrene, C ₁ - to C ₁₈ -alkyl esters of acrylic acid or methacrylic acid, for example methyl acrylate, ethyl acrylate, N-propyl acrylate, isopropyl acrylate, n-butyl acrylate, tert-butyl acrylate and isobutyl acrylate as well as isobutyl methacrylate, n-butyl methacrylate and n-butyl methacrylate . Acrylonitrile, methacrylonitrile, vinyl acetate, vinyl propionate and vinyl butyrate are also suitable. Mixtures of the group 2 monomers can also be used in the copolymerization, for example mixtures of styrene and isobutyl acrylate. The solution copolymers used as emulsifiers can optionally also contain copolymerized monomers of group (3), for example monoethylenically unsaturated C ₃ to C ₅ carboxylic acids or their anhydrides, for example acrylic acid, methacrylic acid, itaconic acid, maleic acid, maleic anhydride or itaconic anhydride. The molar ratio of (1): (2): (3) is 1: 2.5 to 10: 0 to 1.5. The copolymer solutions thus obtained are diluted with water and, in this form, serve as a protective colloid for the polymerization of the above-mentioned monomer mixtures of components (a) and (b) and, if appropriate, (c). Monomers of group (a) are styrene, acrylonitrile, methacrylonitrile or mixtures of styrene and acrylonitrile or of styrene and methacrylonitrile. The monomers of group (b) used are acrylic acid and / or methacrylic acid esters of C ₁ to C ₁₈ alcohols and / or vinyl esters of saturated C ₂ to C ₄ carboxylic acids. This group of monomers corresponds to the monomers of group (2), which has already been described above. Preferably used as the monomer of group (b) are butyl acrylate and butyl methacrylate, for example isobutyl acrylate, n-butyl acrylate and isobutyl methacrylate. Monomers of group (c) are, for example, C ₃ -C ₅ -monoethylenically unsaturated carboxylic acids, acrylamidomethylpropanesulfonic acid, sodium vinyl sulfonate, vinylimidazole, N-vinylformamide, acrylamide, methacrylamide and N-vinylimidazoline. 1 to 32 parts by weight of a monomer mixture of components (a) to (c) are used per 1 part by weight of the copolymer. The monomers of components (a) and (b) can be copolymerized in any ratio, for example in the molar ratio 0.1: 1 to 1: 0.1.

The monomers of group (c) are used for modification if necessary the properties of the copolymers used.

(a) 20 bis 65 Gew.-% Styrol, Acrylnitril und/oder Methacrylnitril,

(b) 80 bis 35 Gew.-% Acrylsäure- und/oder Methacrylsäureestern von einwertigen gesättigten C₃- bis C₈-Alkoholen und

(c) 0 bis 10 Gew.-% anderen monoethylenisch ungesättigten copolymerisierbaren Monomeren

in Gegenwart von Radikale bildenden Initiatoren nach Art einer Emulsionspolymerisation in einer wäßrigen Lösung einer abgebauten Stärke als Schutzkolloid hergestellt. Die abgebaute Stärke hat vorzugsweise Viskositäten η_i = 0,04 bis 0,50 dl/g. Diese Stärken sind einem oxidativen, thermischen, azidolytischem oder einem enzymatischen Abbau unterworfen worden. Für diesen Abbau können sämtliche nativen Stärken eingesetzt werden, z.B. Stärken aus Kartoffeln, Weizen, Reis, Tapioka und Mais sowie Stärken mit Amylopektingehalten von mindestens 95, vorzugsweise 98 bis 100 Gew.-%, z.B. Wachsmaisstärke, Wachskartoffelstärke, Wachsweizenstärke oder Mischungen der genannten Stärken. Außerdem sind chemisch modifizierte Stärken einsetzbar, wie Hydroxyethyl-, Hydroxypropyl- oder quaternisierter Aminoalkylgruppen enthaltende Stärken mit Viskositäten in dem obenangegebenen Bereich. Besonders geeignet sind oxidativ abgebaute Kartoffelstärken, kationisierte, abgebaute Kartoffelstärken oder Hydroxyethylstärke. Die Mischung aus leimend wirkender Copolymerisatdispersion und einer nicht aufgeschlossenen Stärke wird vorzugsweise mindestens 10 Minuten bei 85°C gerührt. Dadurch wird die Stärke aufgeschlossen.The finely divided, aqueous dispersions described as sizing agents for paper, which are known from EP-0 257 412 and EP-B-0 276 770, are preferably used. These dispersions are obtained by copolymerizing

(a) 20 to 65% by weight of styrene, acrylonitrile and / or methacrylonitrile,

(b) 80 to 35% by weight of acrylic acid and / or methacrylic acid esters of monohydric saturated C ₃ to C ₈ alcohols and

(c) 0 to 10% by weight of other monoethylenically unsaturated copolymerizable monomers

prepared in the presence of free radical initiators in the manner of an emulsion polymerization in an aqueous solution of a degraded starch as a protective colloid. The degraded starch preferably has viscosities η _i = 0.04 to 0.50 dl / g. These starches have been subjected to oxidative, thermal, acidolytic or enzymatic degradation. All native starches can be used for this degradation, for example starches from potatoes, wheat, rice, tapioca and corn, and starches with amylopectin contents of at least 95, preferably 98 to 100% by weight, for example waxy corn starch, wax potato starch, wax wheat starch or mixtures of the starches mentioned . In addition, chemically modified starches can be used, such as starches containing hydroxyethyl, hydroxypropyl or quaternized aminoalkyl groups with viscosities in the range given above. Oxidatively degraded potato starches, cationized, degraded potato starches or hydroxyethyl starch are particularly suitable. The mixture of size-acting copolymer dispersion and an undigested starch is preferably stirred at 85 ° C. for at least 10 minutes. This unlocks the strength.

The degraded starches act as emulsifiers in the copolymerization of the monomers (a) to (c) in an aqueous medium in the manner of an emulsion polymerization. The monomers are copolymerized in an aqueous solution which contains 1 to 21, preferably 3 to 15% by weight of degraded starch. In 100 parts by weight of such a solution, 10 to 140, preferably 40 to 100 parts by weight of the monomer mixture of (a) and (b) and optionally (c) are usually polymerized. The diameter of the dispersed polymer particles is 50 to 350, preferably 100 to 250 nm. Also suitable as monomer of group (b) are vinyl esters of C ₂ - to C ₄ -saturated carboxylic acids. Suitable monomers of group (c) are, for example, acrylamide, methacrylamide, stearyl acrylate, stearyl methacrylate, palmitylacrylate, acrylic acid, methacrylic acid, maleic acid, maleic anhydride, itaconic acid, vinylsulfonic acid, acrylamidopropanesulfonic acid and acrylic and methacrylic acid esters of amino alcohols, for example dimethylaminoethylamylamethylataminate, dimethylaminoethyl amyl acrylate dimethyl methylethyl amyl acrylate dimethyl methylethyl amyl acrylate,

The paper sizing mixtures according to the invention are produced by known processes, cf. DE-A-32 35 529 and WO-A-94/05855. The procedure is, for example, that (A) finely divided, aqueous dispersions of C ₁₄ -C ₂₂ -alkyldiketenes, which can be obtained by dispersing the alkyldiketenes in water in the presence of cationic starch with an amylopectin content of at least 95%, with ( B) finely divided, aqueous polymer dispersions, which are a sizing agent for paper, mixed together or C ₁₄ - to C ₂₂ -alkyldiketenes in a mixture of aqueous solutions of cationic starches with an amylopectin content of at least 95%, the starches being converted into a water-soluble form have been and emulsified finely divided, aqueous polymer dispersions, which are a size for paper, at temperatures of at least 70 ° C. The emulsification is preferably carried out here under the action of high shear forces, for example in so-called homogenizers. The resulting emulsions are preferably rapidly cooled to room temperature. The resulting dispersions of paper size mixtures have a pH in the range from 2 to 4, preferably the pH is 3. The paper size mixtures can also be prepared by mixing components (A) and (B), for example in a stirred kettle and this mixture may be homogenized under the action of high shear forces at temperatures of, for example, 20 to 70.degree. The paper size mixtures according to the invention contain, for example, 1 to 55, preferably 10 to 30% by weight of alkyldiketenes and 1 to 60, preferably 3 to 25% by weight of finely divided polymer dispersions, in each case based on the solids.

For the production of the paper size mixtures according to the invention used for example on 1 part by weight (diketene) component (A) 0.1 to 1.2, preferably 0.3 to 0.9 parts by weight Polymer dispersion of component (B), based on the Solids. For example, you can have a single finely divided aqueous solution Polymer dispersion or a mixture of 2 or more Use polymer dispersions, each a sizing agent for Are paper. The particle diameter of the finely divided aqueous Polymer dispersions are, for example, 50 to 400, preferably 100 to 250 nm. The sizing agent mixtures according to the invention are stable in storage, i.e. they do not tend to separate and don't get stuck either. You also have a very low viscosity (e.g. after storage of The viscosity is below 90 days at room temperature 100 mPas, measured in a Brookfield viscometer 100 rpm, and a temperature of 25 ° C with spindle No. 1) and are also characterized by a high stability against the Exposure to shear forces, such as when pumping occur. The sizing mixtures are called bulk and Surface sizing agent used for paper, cardboard and cardboard. Use as a mass sizing agent is preferred during production of paper.

The percentages in the examples mean% by weight, the parts are parts by weight.

Examples Polymer dispersion 1

In a 1 l four-necked flask equipped with a stirrer, reflux condenser, dosing device and a device for working under a nitrogen atmosphere 34.0 g starch A as well 8.4 g of starch B suspended in 148 g of water and stirred on Heated to 85 ° C.

Starch A is a degraded cationic potato starch with a viscosity η _i of 0.47 dl / g, a degree of substitution of 0.015-COOH and 0.027 N mol / mol glucose units and a solids content of 83%.

Starch B is a degraded, cationic potato starch with a viscosity η _i of 1.16, a degree of substitution of 0.07 N mol / mol glucose units and a solids content of 83%.

After 30 minutes at 85 ° C., 2.6 g of an aqueous 10% calcium acetate solution and 10 g of a 1% enzyme solution (α-amylase A) are added. After a further 20 minutes at 85 ° C, the enzymatic starch breakdown is stopped by adding 1.5 g of glacial acetic acid. Then 16.5 g of a 1% iron (II) sulfate solution and 1.75 g of 30% hydrogen peroxide are added. After 20 minutes the hydrogen peroxide has decomposed and the oxidative starch degradation has ended. The intrinsic viscosity of the starch mixture is then 0.08 dl / g. Then 1.8 g of 30% hydrogen peroxide are added and an emulsion is immediately started which consists of 93.7 g of acrylonitrile, 76.4 g of n-butyl acrylate and a solution of 0.2 g of Na-C ₁₄ -alkyl sulfonate 50 g of water consist, add 50 g of a 3.12% hydrogen peroxide solution evenly within 1 hour and simultaneously separately within 1.75 hours. During this time and 60 minutes after the end of the monomer metering, the temperature of the reaction mixture is kept at 85 ° C. A dispersion with a solids content of 41.0% and a particle diameter (without starch shell) of 100-150 nm is obtained. The dispersion is diluted to a solids content of 33% by adding water.

Polymer dispersion 2

A mixture of 20 parts (1.92 mol) styrene, 7 parts (0.41 mol) dimethylaminopropyl methacrylamide, 3.5 parts (0.486 mol) acrylic acid and 10 parts acetic acid was added inside of 1 hour using a pump in a heated to 90 ° C Pumped boiler. Simultaneously and also within 1 hour with the help of another metering device, 2 parts of azoisobutyronitrile were added and 10 parts of acetic acid. The mixture was heated to a temperature of 90 ° C for 30 min and then in Dissolved 180 parts of water. Then 0.01 part of iron sulfate was added and polymerized a mixture therein at a temperature of 85 ° C of 32 parts of styrene and 32 parts of isobutyl acrylate. Separately 33 parts of a 6% hydrogen peroxide solution were added continuously to the prepolymer within 2 hours. After post-polymerization for 1 hour at a temperature of 85 ° C resulted in a finely divided dispersion with a solids content of 31.4% and a particle diameter of 150-250 nm Dispersion is achieved by adding water to a solids content diluted by 20%.

example 1

A 2.80% aqueous solution of a commercially available solution is prepared cationic waxy maize starch (D.S. 0.03, amylopectin content > 98%) by putting the required amount of starch in water suspended and the suspension at a temperature for 15 minutes at 95 ° C. Adds to 85 parts of the starch solution available in this way 15 parts of the polymer dispersion 1 are obtained at a temperature of 85 ° C. to. The mixture is stirred for 10 minutes.

16 parts of a C ₁₆ / C ₁₈ -alkyldiketene melt are added to 84 parts of the mixture of waxy maize starch and polymer dispersion 1 described above and the mixture is briefly treated with an Ultraturrax. This mixture is then homogenized twice at 150 bar in an intensive mixer. The emulsion is then rapidly cooled to room temperature. The properties of the size dispersion are given in Table 1.

Example 2

A 3.66% aqueous solution of a commercially available solution is prepared cationic waxy maize starch (D.S. 0.03, amylopectin content > 98%) by adding the required amount of starch in water suspended and the suspension in the jet cooker at one Temperature of 125 ° C. To 65 parts of the so available Starch solution is added at a temperature of 85 ° C 35 parts of the Polymer dispersion 2 too. The mixture is then 10 min. touched.

84 parts of the above-described mixture of the aqueous solution of the digested cationic starch and the polymer dispersion 2 are added to 16 parts of a C ₁₆ / C ₁₈ alkyldiketene melt and the mixture is briefly treated with an Ultraturrax. This mixture is then treated twice in a homogenizer at 150 bar and then quickly cooled to room temperature. The properties of the paper sizing mixture are given in Table 1.

Example 3

A 4.17% aqueous solution of a commercially available cationic waxy maize starch (DS 0.04, amylopectin content> 98%) is prepared by first suspending the starch in water and digesting it in a jet cooker at a temperature of 125.degree . 0.1 part of the sodium salt of a lignin sulfonic acid and then 20 parts of a C ₁₆ / C ₁₈ alkyldiketene melt are then added to the starch solution and the mixture is treated with an Ultraturrax. The initially coarse suspension is passed through a homogenizer twice at a temperature of 85 ° C. and a pressure of 150 bar and then rapidly cooled to room temperature.

90 parts of the alkyldiketene dispersion described above then with 10 parts of polymer dispersion 1 with stirring mixed and twice in a homogenizer under one Treated pressure of 150 bar. The properties of the paper sizing mixture are given in Table 1.

Example 4

A commercial cationic waxy maize starch (DS 0.04, amylopectin content 100%) is introduced into water in such an amount that a 4.17% aqueous suspension is formed. This suspension is then digested in a jet cooker at a temperature of 125 ° C., so that an aqueous starch solution is obtained, to which 0.15 part of the sodium salt of a lignosulfonic acid and then 25 parts of a C ₁₆ / C ₁₈ alkyl diketene melt are added. The mixture is first treated with an Ultraturrax and then twice in a homogenizer under a pressure of 150 bar and a temperature of 85 ° C. and then quickly cooled to room temperature.

70 parts of the alkyl diketene emulsion described above are added Add 30 parts of polymer dispersion 2 and homogenize the resulting Mix twice in a homogenizer at a pressure of 150 bar. The properties of the paper sizing mixture thus obtainable are given in Table 1.

Comparative Example 1

First, a 5.13% aqueous suspension of a commercially available cationic starch (D.S. 0.02, amylopectin content 70%), gave 50 parts of this suspension to 50 parts of the Polymer dispersion 1 and closed the starch by 10 minutes Heat in the mixture with the polymer dispersion 1 to one Temperature of 85 ° C.

To 78 parts of the mixture of the digested starch and the Polymer dispersion 1 was given a melt heated to 90 ° C. 20 parts of stearyl diketene and 2 parts of stearic acid oleate and The mixture was then homogenized as described in Example 1. A stable, 20% strength aqueous stearyl diketene emulsion was obtained, which, apart from stearyl diketene, 2% strong, 2% stearic acid oleylester as a stabilizer and 12.9% of the polymer dispersion 1 contained. The properties of the dispersion are given in Table 1.

Comparative Example 2

Example 1 was repeated with the changes that a 5.13% strength aqueous suspension of a commercially available cationic starch (degree of substitution 0.02, amylopectin content 75%) was prepared, mixed with 50 parts of polymer dispersion 2 and the starch was heated to 85 by heating the mixture ° C for a total of 10 minutes. A melt of 20 parts of stearyl diketene and 2 parts of stearic acid ethyl ester, heated to 90 ° C., was then added to 78 parts of the mixture of digested starch and polymer dispersion 2 thus obtained and the melt therein was emulsified as described in Example 1. The properties of the sizing mixture are given in Table 1. example Viscosity after manufacture [mPas] Viscosity after 3 months [mPas] middle Particle size distribution [µm] Final sizing (Cobb) Stability during storage (3 months) 1 14.0 16.1 1.21 25th stable 2nd 22.8 32.8 1.65 27 stable 3rd 13.9 45.3 2.05 30th stable 4th 30.8 43.7 2.62 30th stable See Example 1 39.2 135 2.20 27 Phase separation See Example 2 27.1 236 2.45 27 Phase separation

The shear stability of the sizing agent mixtures described in the examples and comparative examples was determined by pumping the mixtures through a 400 μm filter using a centrifugal pump. 500 ml each of the paper sizing mixture was used and the temperature of the mixture was kept at 25 ° C. during the test. Table 2 shows the times after which the filter became blocked or the test was stopped. Shear stability test (pump test) Sizing agent mixture according to example Termination after [min] Remarks 1 60 Filter free 2nd 55 Filter clogged 3rd 60 Filter free 4th 44 Filter clogged See example 1 15 Filter clogged See example 2nd 23 Filter clogged

Claims (11)

1. A paper sizing agent mixture comprising

   (A) finely divided, aqueous dispersions of C₁₄- to C₂₂-alkyldiketenes, which are obtainable by dispersing the alkyldiketenes in water in the presence of a cationic starch, and

   (B) finely divided, aqueous polymer dispersions which are a sizing agent for paper,

   wherein the amylopectin content of the cationic starch of component (A) is at least 95%.
2. A paper sizing agent mixture as claimed in claim 1, wherein the amylopectin content of the cationic starch is from 98 to 100%.
3. A paper sizing agent mixture as claimed in claim 1, wherein the cationic starch is a cationic waxy cornstarch.
4. A paper sizing agent mixture as claimed in one of claims 1 to 3, wherein in the preparation of the component (A) the dispersion of the alkyldiketenes in water is additionally carried out in the presence of lignosulfonic acid, condensates of formaldehyde and naphthalenesulfonic acids, polymers containing styrenesulfonic acid groups or compounds containing the alkali metal and/or ammonium salts of the sulfonic acid groups mentioned.
5. A process for preparing paper sizing agent mixtures by mixing

   (A) finely divided, aqueous dispersions of C₁₄- to C₂₂-alkyldiketenes, which are obtainable by dispersion of the alkyldiketenes in water in the presence of cationic starch, with

   (B) finely divided, aqueous polymer dispersions which are a sizing agent for paper,

   or by emulsifying C₁₄- to C₂₂-alkyldiketenes in a mixture of aqueous suspensions of cationic starches and finely divided, aqueous polymer dispersions which are a sizing agent for paper, at at least 70°C, wherein the amylopectin content of the cationic starches is at least 95%.
6. A process as claimed in claim 5, wherein the amylopectin content of the cationic starches is from 98 to 100%.
7. A process as claimed in claim 5 or 6, wherein the starches employed are cationic waxy cornstarches.
8. A process as claimed in one of claims 5 to 7, wherein the degree of substitution (D.S.) of the cationic starches is from 0.010 to 0.150.
9. A process as claimed in claim 8, wherein the degree of substitution (D.S.) of the cationic starches is below 0.045.
10. A process as claimed in claim 8, wherein the degree of substitution (D.S.) of the cationic starches is from 0.020 to 0.040.
11. The use of the paper sizing agent mixtures as claimed in claims 1 to 4 as engine and surface sizing agents for paper, card and cardboard.