RU2429323C2 - Paper sizing - Google Patents

Abstract

FIELD: textile, paper.

SUBSTANCE: invention relates to a water dispersion (its version) of a cellulose-active gluing substance (its version), a method to produce the water dispersion (its version), application of the water dispersion and a method of paper making. The water dispersion of the cellulose-active gluing substance contains an acid anhydride, an anion polyelectrolyte and a nitrogen-containing organic compound, which is an amine or a corresponding quaternary ammonia compound, having the molecular weight of less than 180 or having one or several hydroxyl groups. The method to produce the water dispersion of the cellulose-active gluing substance and its version includes dispersion of the acid anhydride in the water phase in presence of the anion polyelectrolyte and the nitrogen-containing organic compound, which is the amine or the corresponding quaternary ammonia compound, having the molecular weight of less than 180 or having one or several hydroxyl groups. The above specified water dispersions of the cellulose-active gluing substance may be used for sizing in mass or for surface sizing in paper making. The method of paper making includes addition of the above-specified water dispersions of the cellulose-active gluing substance to the water suspension of cellulose with subsequent dehydration of the produced suspension on a net of a paper-making machine or by application of these dispersions onto a surface of a cellulose sheet.

EFFECT: improved stability of the gluing water dispersion and efficiency of sizing, energy and capital cost saving.

41 cl, 13 tbl, 7 ex

Description

The scope of the invention

The present invention relates to paper sizing, and more particularly to aqueous dispersions of a cellulose-active sizing agent and to their preparation and use.

BACKGROUND OF THE INVENTION

Cellulose-active sizing agents, such as those based on alkenyl succinic anhydride (ASA), are widely used in papermaking at a neutral or slightly alkaline pH of the pulp in order to give the paper or paperboard some degree of resistance to wetting or penetration by aqueous liquids. Cellulose-active sizing paper adhesives are usually provided in the form of dispersions containing an aqueous phase and finely divided solids or droplets of a sizing agent dispersed therein. Dispersions are usually prepared using a dispersant system consisting of an anionic compound, for example sodium lignosulfonate, in combination with a high molecular weight amphoteric or cationic polymer, for example cationic starch, polyamine, polyamidamine or vinyl polymer obtained by step polymerization.

International Patent Application WO 96/17127 describes aqueous dispersions that contain a cellulose-active sizing agent and particles of colloidal anionic silica modified with aluminum.

International patent application WO 97/31152 describes aqueous dispersions that contain a reactive adhesive and an anionic micronized substance. In addition, dispersions may contain no more than 2% (by weight of a chemically active adhesive) of a surfactant. The surfactant may be non-ionic or anionic.

International patent application WO 98/33979 A1 describes an aqueous dispersion of a cellulose-active sizing agent and a dispersant system containing a cationic organic compound and an anionic stabilizer.

Although significant improvements have been made in the preparation, properties and performance of aqueous dispersions of akenyl succinic anhydride, there are still some technical problems associated with the use of such dispersions. Dispersions of alkenyl succinic anhydride usually show poor stability, which undoubtedly leads to difficulties in handling these dispersions, for example, during storage and use. One additional drawback is that aqueous dispersions cannot be stored for longer periods of time because alkenyl succinic anhydride is easily hydrolyzed and thus becomes ineffective as a sizing agent.

Consequently, alkenyl succinic anhydride is usually supplied to paper mills in the form of a liquid, which is then dispersed prior to its use as a sizing agent, and the resulting dispersion is usually used within 2 hours to avoid problems associated with insufficient stability and loss of sizing efficiency. The equipment used to produce the dispersions provides large shear forces in order to be able to leave surfaces free and produce dispersions having an appropriate particle size. Such equipment is often both complex and expensive, and due to large shear forces, a significant amount of energy is usually required.

The present invention is the creation of an aqueous dispersion of cellulose-active sizing agent, which can be easily prepared using small shear forces and low energy consumption. An additional objective of this invention is the creation of an aqueous dispersion of cellulose-active sizing agent, showing improved stability and efficiency of sizing. Additional tasks will be apparent further.

Summary of the invention

The invention relates to an aqueous dispersion of a cellulose-active sizing agent containing acid anhydride, an anionic polyelectrolyte and a nitrogen-containing organic compound, which is an amine or its corresponding quaternary ammonium base having a molecular weight of less than 180 and / or having one or more hydroxyl groups.

The invention further relates to a method for producing an aqueous dispersion of a cellulose-active sizing agent, which comprises dispersing an acid anhydride in the aqueous phase in the presence of an anionic polyelectrolyte and a nitrogen-containing organic compound, which is an amine or its corresponding quaternary ammonium base having a molecular weight of less than 180 and / or having one or more hydroxyl groups.

In addition, the invention relates to the use of an aqueous dispersion of a cellulose-active sizing agent as a mass sizing agent or a surface sizing agent in paper manufacturing. The invention further relates to a paper production method, which comprises adding an aqueous dispersion of cellulose-active sizing agent to an aqueous suspension of cellulose and dewatering the resulting suspension on a paper machine grid, as well as a method of manufacturing paper, which comprises applying an aqueous dispersion of cellulose-active sizing agent to a web cellulose.

DETAILED DESCRIPTION OF THE INVENTION

It has been found that according to the present invention, improved sizing of paper can be achieved using this aqueous dispersion of cellulose-active sizing agent. It has also been found that these dispersions show better stability compared to conventional dispersions. In addition, it was found that to obtain aqueous dispersions, lower shear forces can be used compared to those that occur in conventional aqueous dispersions of a cellulose-active sizing agent. Thanks to the present invention, it becomes possible to use simple equipment that saves energy and capital costs and creates small shear forces, such as static mixers. Thus, the present invention provides significant economic and technical benefits.

The cellulose-active sizing agent according to the invention can be selected from any acid anhydride sizing agent known in the art. A suitable wetting agent is a hydrophobic acid anhydride. Suitable hydrophobic acid anhydrides can be characterized by the following general formula (I), in which R ¹ and R ² are independently selected from saturated or unsaturated hydrocarbon groups which suitably contain from 8 to 30 carbon atoms, or R ¹ and R ² together with part -C-O-C- can form a ring with 5-6 elements, optionally additionally substituted with hydrocarbon groups containing up to 30 carbon atoms:

Examples of suitable acid anhydrides are alkyl and alkenyl succinic anhydrides, e.g. tri-isobutenyl succinic anhydride, 1-octyl-2-decenyl succinic anhydride and 1-hexyl-2-octenyl succinic anhydride. Examples of suitable acid anhydrides further include compounds described in US Pat. Nos. 3,102,064, 3,821,069, 3,968,005, 4,040,900 and 4,522,686; and Re. 29960, which are incorporated herein by reference.

The cellulose-active sizing agent according to the invention may contain one or more acid anhydrides, for example, one or more alkyl and / or alkenyl succinic anhydrides. Typically, the acid anhydride of this invention is a liquid at room temperature.

The dispersion according to the invention comprises a dispersant or dispersant system comprising an anionic polyelectrolyte and a nitrogen-containing organic compound. When used together, these compounds are effective as a dispersant for an acid anhydride sizing agent, although when used separately, an anionic polyelectrolyte and a nitrogen-containing organic compound may not be effective as a dispersant. The dispersion is preferably anionic, i.e. the dispersant or dispersant system has a common anionic charge.

The anionic polyelectrolyte according to the invention can be selected from organic and inorganic compounds and can be obtained from natural or artificial sources. Anionic polyelectrodate has two or more anionic groups, which can be the same or different types. Examples of suitable anionic groups, i.e. groups that are anionic or become anionic in the aqueous phase include silanol, aluminosilicate, phosphate, phosphonate, sulfate, sulfonate, sulfonic and carboxylic acid groups, as well as their salts, usually ammonium or alkali metal salts (usually sodium). Anionic polyelectrolytes can be soluble in water, for example, linear and branched anionic polyelectrolytes or dispersible in water, for example, crosslinked and / or dispersed anionic polyelectrolytes. Water-dispersible and dispersed anionic polyelectrolytes are preferably colloidal, i.e. have a particle size in the colloidal range. The colloidal particles suitably have a size of from 1 nm to 100 nm, preferably from 2 to 70 nm, and most preferably from 2 to 40 nm. Water-dispersible and dispersed anionic polyelectrolytes may contain aggregated and / or non-aggregated particles.

Examples of suitable organic anionic polyelectrolytes are anionic polysaccharides, namely starch, guar gum, cellulose, chitin, chitosan, glycan, galactan, glucan, xanthan gum, mannan and dextrin. Further examples of suitable organic anionic polyelectrolytes are synthetic anionic polymers, such as condensation polymers, for example polyurethane and polymers based on naphthalene and melamine, for example condensation formaldehyde naphthalene sulfotates and polymers based on melaminesulfonic acid, and vinyl polymers obtained by stepwise polymerization from ethylene including anionic or potentially anionic monomers, for example acrylic acid, methacrylic acid, maleins w acid, itaconic acid, crotonic acid, vinylsulfonic acid, sulfonated styrene and phosphates of hydroxyalkyl acrylates and methacrylates, optionally copolymerized with non-ionic ethylenically unsaturated monomers, e.g. akrialamidom, alkyl acrylates, styrene and acrylonitrile and derivatives of such monomers, vinyl esters, etc.

Examples of other suitable organic non-ionic polyelectrolytes are water soluble branched polymers and water dispersible crosslinked polymers obtained by polymerizing a mixture of monomers containing one or more ethylenically unsaturated anionic or potentially anionic monomers and, optionally, one or more other ethylenically unsaturated monomers, in the presence of one or more ethylenically unsaturated monomers polyfunctional crosslinking agents. The presence of a multifunctional crosslinking agent in the monomer mixture makes it possible to obtain branched polymers, weakly crosslinked polymers and highly crosslinked polymers that are dispersible in water. Examples of suitable polyfunctional crosslinking agents are compounds having at least two ethylenically unsaturated bonds, for example N, N-methylene bis (meth) acrylamide, polyethylene glycol (meth) acrylate, N-vinyl (meth) acrylamide, divinylbenzene, triallylammonium salts and N-methylallyl (meth) acrylamide; compounds having an ethylenically unsaturated bond and a reactive group, for example glycidyl (meth) acrylate, acrolein and methylol (meth) acrylamide; and compounds having at least two reactive groups, for example dialdehydes such as glyoxal, diepoxy compounds and epichlorohydrin.

Organic anionic polyelectrolyte has an anionic substitution degree (DS _A ) of typically from 0.01 to 1.4, suitably from 0.1 to 1.2, and preferably from 0.2 to 1.0. An anionic polyelectrolyte may contain one or more cationic groups, since it has a common anionic charge. The molecular weight of the anionic polyelectrolyte can vary widely; the molecular weight is usually in excess of 200 and suitably in excess of 500, while the upper limit is usually 10 million and preferably 2 million.

Examples of suitable inorganic anionic polyelectrolytes are anionic siliceous materials, for example silica-based anionic materials obtained using silicic acid, and smectite type clay. These anionic polyelectrolytes usually have negative silanol, aluminosilicate or hydroxyl groups. Examples of suitable inorganic anionic polyelectrolytes are polysilicic acid, polysilicates, polyaluminosilicates, silica-based colloidal particles, for example silica particles, aluminized (modified with aluminum) silica and aluminosilicate, polysilicate microgels, polyaluminosilicate microgels, silica gels, silica gels, silicones bentonite, hectorite, beidelite, nontronite and saponite. Preferred anionic polyelectrolytes include silica-based materials, for example silica-based colloidal particles.

The nitrogen-containing organic compound according to the invention is an amine or its corresponding quaternary ammonium base. Suitable nitrogen-containing organic compounds include primary, secondary, and tertiary amines and their corresponding quaternary ammonium bases. Suitable nitrogen-containing organic compounds further include monoamines, diamines and polyamines and their corresponding quaternary ammonium bases. Suitable ammonium bases include protonated, alkylated, arylated and alkarylated amines of the aforementioned type, which can be formed by the reaction of amines with, for example, acids, for example hydrochloric acid, and methyl chloride, dimethyl sulfate and benzyl chloride. In a preferred embodiment, the nitrogen-containing organic compound is an amine or a corresponding quaternary ammonium base having one or more hydroxyl groups. One or more hydroxyl groups are preferably present at the extreme position of one or more substituents of the nitrogen-containing compound, i.e. ending with a hydroxyl group of an amine or a corresponding quaternary ammonium base.

Examples of suitable nitrogen-containing organic compounds are the following amines and their corresponding quaternary ammonium bases: diethylene triamine, triethylenetetramine, hexamethylenediamine, diethylamine, dipropylamine, di-isopropylamine, cyclohexylamine, pyrrolidine, guanidine, triethanolamine, monoethanol ethanol, ethanol, ethanol, ethanol, ethanol, ethanol, ethanol . Further examples of suitable nitrogen-containing organic compounds are choline hydroxide, tetramethyl ammonium hydroxide and tetraethyl ammonium hydroxide. Preferred nitrogen-containing organic compounds include triethanolamine and its corresponding quaternary ammonium bases.

The molecular weight of a nitrogen-containing organic compound can vary widely. In a preferred embodiment of the invention, the molecular weight of the amine or its corresponding quaternary ammonium base is less than 180, suitably up to 170 and preferably up to 160. The molecular weight is usually at least 30. The molecular weight of the quaternary ammonium base of the amine indicated here means the molecular weight the cationic part of the quaternary ammonium compound and this means that the anionic part of the quaternary ammonium compound is not included in the above values olekulyarnoy mass. For nitrogen-containing organic compounds that are selected from amines and their corresponding quaternary ammonium bases having one or more hydroxyl groups, the molecular weights can be higher, for example, up to 500 and usually up to 300, although the above molecular weights are also suitable for such compounds.

In the aqueous dispersion or emulsion in question, the acid anhydride may be present in an amount of from about 0.1 to about 50 wt.%, Suitably from 0.1 to about 30 wt.% And preferably from about 1 to about 20 wt.% Based on the weight water dispersion. The anionic polyelectrolyte is present in an amount up to about 100 wt.%, Usually from 0.1 to 15 wt.%, Suitably from 0.5 to 10 wt.% And preferably from 1 to 7 wt.%, Based on the weight of the acid anhydride. The nitrogen-containing organic compound may be present in an amount up to 20 wt.%, Usually from 0.1 to 15 wt.%, Suitably from 0.5 to 10 wt.% And preferably from 1 to 7 wt.% Based on the weight of the acid anhydride . In addition to acid anhydride, an anionic polyelectrolyte and a nitrogen-containing organic compound, optional additional compounds may be present in the dispersion. Examples of such compounds are mono-, di- and polyanionic and nonionic surfactants and dispersants, stabilizers, fillers and preservatives, such as hydrolyzed acid anhydrides, for example the aforementioned hydrolyzed alkyl and alkenyl acid anhydrides, preferably hydrolyzed alkenyl succinic anhydrides, for example hydrolyzed acid anhydrides in the form of derivatives of a carboxylic acid and / or carboxylic acid ester, anionic surfactants such as phosphoric acid esters you, such as ethoxylated phosphate esters, alkyl sulphates, sulphonates and phosphates, alkylaryl sulphates, sulphonates and phosphates, such as sodium lauryl sulfonate and ethoxylated, phosphated isotridecyl alcohol. If present, the content of such additional compounds in the dispersion may be from 0.1 to 15 wt.%, Suitably from 1 to 10 wt.% And preferably from 2 to 7 wt.%, Based on the weight of the acid anhydride. Water is also present in the dispersion and can make up the rest of the dispersion up to 100% by weight.

The dispersion according to the invention can be obtained by forming a mixture containing acid anhydride, an anionic polyelectrolyte and a nitrogen-containing organic compound, as defined above, and dispersing the mixture in the presence of water. The dispersion components can be mixed in any order, but preferably the anionic polyelectrolyte and the nitrogen-containing organic compound are mixed and diluted with water to an appropriate concentration, and then the acid anhydride is dispersed therein. The mixture can be dispersed using suitable dispersion equipment that provides a sufficient degree of dispersion, such as a static mixer, creating relatively small shear forces. The resulting dispersion contains drops of acid anhydride, usually having a diameter of from 0.1 to 10 microns.

The aqueous sizing dispersions according to the invention can be used in the usual way in the manufacture of paper using cellulose fibers of any kind, and these aqueous sizing dispersions can be used both for surface sizing and for sizing in bulk. As used herein, the term “paper” covers not only paper but also all kinds of cellulosic materials in the form of a sheet or web, including, for example, paperboard. In addition, the cellulose suspension and the finished paper may contain mineral fillers, while the content of cellulose fibers is usually at least 50 wt.% Based on the dry weight of the substance of the suspension of cellulose or the weight of the finished paper. Examples of common mineral fillers are kaolin, titanium dioxide, gypsum, talc and natural or artificial calcium carbonates, such as chalk, ground marble and precipitated calcium carbonate. The present invention further relates to a paper production method in which the aqueous sizing dispersion in question is either added to an aqueous suspension of cellulose or applied to a sheet or web of cellulose. The amount of cellulose-active sizing agent that is either added to the cellulose suspension to be dehydrated on a grid of a paper machine for forming paper or applied as a surface adhesive to the surface of a cellulose sheet or web — usually in a size press — is suitably from 0.01 to 1.0 wt.%, Preferably from 0.05 to 0.5 wt.% Calculated on the dry weight of the substance of the suspension of cellulose and optional fibers, and this amount depends mainly on the amount of sizing pulp or paper and the desired degree of sizing.

Aqueous sizing dispersions according to the invention are particularly useful in preparing paper from an aqueous suspension of cellulose that has high conductivity. The conductivity of the suspension, which is dehydrated on a paper machine grid, can range from 0.3 mS / cm to 10 mS / cm. According to this invention, good results can be achieved with a conductivity of at least 2.0 mS / cm; they can be achieved appreciably at least 3.5 mS / cm, especially at least 5.0 mS / cm and even at least 7.5 mS / cm. Conductivity can be measured using standard equipment such as the WTW LF 330 instrument supplied by Christian Berner. The above values are determined appropriately by measuring the conductivity of the cellulose suspension that is supplied to or in the headbox of the paper machine, or, on the other hand, by measuring the conductivity of the recycled water resulting from the dewatering of the suspension. High conductivity values mean high levels of salts (electrolytes) that can be extracted from materials used to form the pulp, from various additives introduced into the pulp, from fresh water supplied to the process, etc. In addition, the salt content is usually higher in processes with intensive recirculation of circulating water, which can lead to a significant accumulation of salts in the water recycled in the process.

In connection with the present invention, of course, chemicals that are usually added to a pulp suspension in paper production, such as substances to increase the filler’s retention capacity, aluminum-containing compounds, dyes, resins to give paper moisture resistance, optical brighteners, etc., can be used. Examples of aluminum-containing compounds are alum, aluminates and polyaluminium-containing compounds, for example polyaluminium chlorides and sulfates. Examples of suitable filler retention agents are cationic polymers, anionic inorganic materials in combination with organic polymers, for example bentonite in combination with cationic polymers, silica sols in combination with polymers or cationic and anionic polymers. Particularly good sizing can be achieved by using the dispersion according to the invention in combination with substances to increase the retention of the filler containing cationic polymers. Suitable cationic polymers include cationic starch, acrylate and acrylamide-based polymers, polyethyleneimine, polyamines, polyamidoamines and poly (diallyldimethylammonium chloride), and combinations thereof. Preferred filler retention agents include cationic starch and acrylamide-based cationic polymers. In a preferred embodiment of the invention, dispersions are used in combination with a system of substances to increase the retention of a filler comprising at least one cationic polymer and an anionic siliceous material, for example, silicon-based particles or bentonite. It is possible to pre-mix one or more components of the dispersion in question with a substance to increase the retention of the filler, for example, an anionic siliceous material before introducing the mixture thus obtained into a cellulose suspension. Thus, the considered aqueous sizing dispersion can be prepared immediately prior to its introduction into the cellulose suspension by bringing the acid anhydride and the nitrogen-containing organic compound into contact with an anionic polyelectrolyte, such as an aqueous siliceous material, for example, silica sol or a suspension of bentonite.

The invention will now be illustrated by the following examples, which, however, are not intended to limit the invention. Parts and percentages are indicated in parts by weight, respectively. and wt.%, unless otherwise specified.

Example 1

Aqueous dispersions according to the invention were obtained in a Hash tube static mixer dispersing alkenyl succinic anhydride (ASA) based on an olefin fraction containing iso-hexadecenyl or iso-octadecenyl succinic anhydride in the presence of a mixture of anionic polyelectrolyte and amine.

The aqueous dispersions used for comparison in this and subsequent examples were prepared in a similar manner, except that no amine and no colloidal silica were used, and high molecular weight amines and / or amines did not have any hydroxyl groups.

The anionic polyelectrolyte used in this example was colloidal silica (Eka NR 590) in the form of an aqueous sol having a SiO ₂ content of 8.1 wt.% And containing silica particles with a specific surface area of 850 m ² / G, which were modified by aluminum. The amine used in this example was triethanolamine (TEA) with a molecular weight of 149.

Anionic polyelectrolyte and amine were mixed in the presence of water to form a mixture that was pumped at one end of the pipe at a flow rate of 3.17 l / min, while concentrated ASA was pumped at the side of the pipe at a flow rate of 0.167 l / min. The pressure drop across the mixer was 3.4 bar. The resulting dispersion had an ASA content of 5 wt.% And an anionic polyelectrolyte content (in this example, SiO ₂ content) of 5.0 wt.% Based on ASA, with the amine content varying from 0 to 2.0 wt. .% per ASA.

Dispersions 1-4 were obtained, shown in Table 1, in which the contents of SiO ₂ and amine are given based on ASA.

Table 1 Dispersion No. SiO ₂ (%) TEA (%) one 5 0 2 5 0.5 3 5 1,0 four 5 2.0

The degree of dispersion of the ASA droplets was measured in a Malvern Mastersizer Microplus after dilution of the dispersion with water to an ASA content of 0.5% by weight. The results are shown in Table 2. D (v 0.1), D (v 0.5) and D (v 0.9) mean that, respectively, 10, 50 and 90% of the particles had a diameter smaller than this size.

table 2 Dispersion No. Particle size (μm) D (v 0,1) D (v 0.5) D (v 0.9) one 0.43 4.64 12,42 2 0.82 2,32 6.88 3 0.50 1.78 5.40 four 0.59 1.43 5.30

As can be seen in Table 2, the dispersions according to the present invention, dispersions No. 2-4, showed smaller particle sizes compared with the dispersion used for comparison, dispersion No. 1.

To evaluate the effectiveness of sizing, paper sheets were prepared according to the standard method SСAN-C26: 76 and the sizing was measured in Cobb-60 values according to the standard method Tappi T441.

Paper sheets were prepared by a method in which dispersions were added to an aqueous suspension of cellulose containing recycled cellulose and having a fiber concentration of 0.5 g / L, a conductivity of 0.7 mS / cm and a pH of about 7.0. Dispersions were added in quantities of 0.5, 1.0 and 1.5 kg / t in terms of ASA and based on the dry weight of the cellulose suspension. A system of substances was used to increase the retention of the filler containing 6 kg / t of cationic potato starch (Perlbond 970) and 0.5 kg / t of silica sol (Eka NP 442) in terms of dry matter and based on the dry matter of the cellulose suspension.

Cobb-60 values were measured; the results are presented in Table 3. A lower Cobb value means absorption of less water and, therefore, better sizing.

Table 3 Dispersion No. Cobb-60 0.5 kg / t 1.0 kg / t 1.5 kg / t one 164 144 95 2 142 42 29th 3 145 38 26 four 48 24 21

As can be seen in Table 3, the dispersions according to the present invention, dispersions No. 2-4, showed improved sizing efficiency compared to the dispersion used for comparison, dispersion No. 1.

Example 2

Dispersions were prepared and their sizing efficiency was evaluated in accordance with the general methods of Example 1, except that different silica contents were used at a constant amine content. The dispersions had an ASA content of 5% by weight based on the weight of the dispersion. The results are shown in Table 4.

Table 4 Dispersion No. SiO ₂ (%) TEA (%) Cobb-60 (1 kg / t) 5 0 2 29th 6 one 2 25 7 3 2 23 8 four 2 21 9 5 2 25

As can be seen in Table 4, the dispersions according to the present invention, dispersions No. 6-9, showed improved sizing efficiency compared to the dispersion used for comparison, dispersion No. 5.

Example 3

The dispersions were prepared and evaluated in accordance with the general methods of Example 1. The dispersions in aqueous suspensions of cellulose having increased conductivity due to the addition of calcium chloride were compared. The conductivity of the suspensions was measured using a WTW LF 330 instrument from Christian Berner. The results are presented in Table 5.

Table 5 Dispersion No. ASA (%) SiO ₂ (%) TEA (%) Conductivity, mS / cm Cobb-60 0.5 kg / t 1.0 kg / t 1.5 kg / t 10 5 0 2 four 128 123 117 eleven 5 5 2 four 126 108 48 10 5 0 2 8 146 141 135 eleven 5 5 2 8 125 105 47

As can be seen in Table 5, the dispersion according to the present invention, dispersion No. 11, showed significantly better sizing efficiency compared to the dispersion used for comparison, dispersion No. 10, when the conductivity of the suspension was increased.

Example 4

Received and evaluated dispersion in accordance with the General methods of Example 1, except that they used different amines. The resulting dispersion had an ASA content of 5 wt.%, An SiO ₂ content of 5 wt.% Based on ASA, and an amine content of 2.0 wt.% Based on ASA.

The amines used were triethanolamine (TEA) having a molecular weight of 149, diethylenetriamine (DETA) having a molecular weight of 103, a fractionated coconut oil amine (FCA) having a molecular weight of about 200, and dehydrogenated fat dimethyl ammonium chloride (DTDMAC) having a molecular weight of a mass of about 530.

Particle sizes are presented in Table 6.

Table 6 Dispersion No. Amine in dispersion Particle size (μm) D (v 0,1) D (v 0.5) D (v 0.9) 12 DTDMAC 0.34 2.05 9.79 13 FCA 0.41 33,2 211.0 fourteen Deta 0.13 0.41 1.86 fifteen Tea 0.11 0.27 0.67

The results of evaluating the effectiveness of sizing are shown in Table 7.

Table 7 Dispersion No. Amine in dispersion Cobb-60 0.5 kg / t 1.0 kg / t 1.5 kg / t 12 DTDMAC 106 44 29th 13 FCA 114 83 39 fourteen Deta 87 26 23 fifteen Tea 51 26 21

As can be seen in Tables 6 and 7, the dispersions according to the present invention, dispersions No. 14 and 15, which contained amines having a molecular weight of less than 180 (dispersions No. 14 and 15) and having hydroxyl groups (dispersion No. 15), showed a smaller particle size and significantly improved sizing efficiency compared to dispersions used for comparison, dispersions No. 12 and 13. This also means that according to the present invention requires less energy to leave surfaces free.

Example 5

Prepared and evaluated dispersion in accordance with the General methods of Example 1, except that they used different anionic polyelectrolytes. The resulting dispersion had an ASA content of 5 wt.%, A SiO ₂ content of 5.0 wt.% Based on ASA, and a triethanolamine content of 0 to 2.0 wt.% Based on ASA. The electrolytes used are shown in Table 8.

Table 8 Anionic Polyelectrolyte Description Trade name The size of the primary particles (nm) A Colloidal Aluminized Silica Eka NP 590 3 B Colloidal silica Eka BMA-0 5.5 C Colloidal silica Bindzil 50/80 34 D Bentonite Hydrocol scaly structure E Bentonite Opazil AV scaly structure

Bentonites were suspended in water (5 wt.% Bentonite) and stored for 5 days to achieve sufficient swelling and delamination.

The particle size was determined and stability was evaluated. Stability was measured 2 hours after receipt. If stability was still maintained after 24 hours, then the particle size was again determined. The term "section." means "separation." The results are shown in Table 9.

The results of evaluating the effectiveness of sizing are shown in Table 10.

Table 10 Dispersion No. Anionic Polyelectrolyte Amine Content (%) Cobb-60 0.5 kg / t 0.75 kg / t 1.0 kg / t 16 A - 128 103 64 17 A 2 89 44 29th eighteen B - 129 62 33 19 B 2 91 40 33 twenty C - 116 102 66 21 C 2 128 45 31 22 D - 120 112 91 23 D 2 88 34 28 24 E - 122 127 120 25 E 2 99 41 29th

As can be seen in Tables 9 and 10, dispersions according to the present invention, dispersions No. 17, 19, 21, 23 and 25, which contained both an anionic polyelectrolyte and a nitrogen-containing organic compound, showed better sizing efficiency, better stability and smaller particle size in comparison with the dispersions used for comparison, dispersions No. 16, 18, 20, 22 and 24, which did not contain any nitrogen-containing organic compounds.

Example 6

Dispersions were obtained and particle size and sizing efficiency of the dispersions were evaluated in accordance with the general methods of Example 1, except that various surfactants and their different contents were used. The anionic polyelectrolyte used was colloidal silica (Eka NP 780) in the form of an aqueous sol having a SiO ₂ content of 7.5 wt.% And containing silica particles with a specific surface area of about 900 m ² / g, which were modified with aluminum. The amine used was triethanolamine (TEA). The resulting dispersion had an ASA content of 5 wt.%, An SiO ₂ content of 5 wt.% Based on ASA, and an amine content of 2.0 wt.% Based on ASA.

No surfactant was added to dispersion No. 26. Hydrolyzed ASA as a surfactant was introduced in dispersions Nos. 27 and 28. The surfactant used in dispersion Nos. 29 was a phosphoric acid ester (poly (hydroxy-1,2-ethanediyl) alpha-isotridecyl-omega-hydroxyphosphate ) Surfactant contents in dispersions are based on ASA. The particle size measurements are shown in Table 11.

Table 11 Dispersion No. Surfactant in dispersion Surfactant Content (%) Particle size (μm) D (v 0,1) D (v 0.5) D (v 0.9) 26 - - 0.33 4.67 14.53 27 hydrolyzed ASA one 0.29 2.42 7.63 28 hydrolyzed ASA 2.5 0.12 0.45 1.83 29th phosphoric ester one 0.17 1.05 4.16

Efficiency of sizing with dispersions was evaluated and dispersions were compared in an aqueous suspension of cellulose containing 70% cellulose (Kraft pulp from birch-pine raw materials in a ratio of 80/20) and 30% filler (CaCO ₃ ).

Table 12 Dispersion No. Conductivity, mS / cm Cobb-60 0.5 kg / t 0.75 kg / t 1.0 kg / t 26 0.4 91 84 70 27 0.4 81 69 54 28 0.4 72 48 31 29th 0.4 76 49 41 26 0.7 87 78 75 27 0.7 81 64 54 28 0.7 76 47 31 29th 0.7 73 52 37

As can be seen from the results presented in Tables 11 and 12, dispersions No. 27, 28 and 29 containing a surfactant showed a smaller particle size and better sizing efficiency than a dispersion that did not contain any surfactant.

Example 7

The dispersions of Example 6 were evaluated for sizing efficiency using aqueous pulp suspensions containing unbleached kraft pulp and having different conductivities. The results are shown in Table 13.

Table 13 Dispersion No. Conductivity, mS / cm Cobb-60 0.5 kg / t 0.75 kg / t 1.0 kg / t 26 0.4 one hundred 72 37 27 0.4 86 42 27 28 0.4 40 28 23 29th 0.4 49 28 22 28 0.7 44 27 22 26 4.0 97 one hundred 76 27 4.0 89 52 28 28 4.0 44 27 23 29th 4.0 102 98 76

As can be seen in Table 13, dispersions No. 27, 28 and 29 containing a surfactant showed better sizing efficiency than a dispersion containing no surfactant, dispersion No. 26.

Claims (41)

1. An aqueous dispersion of cellulose-active sizing agent containing acid anhydride, an anionic polyelectrolyte and a nitrogen-containing organic compound, which is an amine or its corresponding quaternary ammonium base having a molecular weight of less than 180. 2. An aqueous dispersion of a cellulose-active sizing agent containing acid anhydride, an anionic polyelectrolyte and a nitrogen-containing organic compound, which is an amine or its corresponding quaternary ammonium base having one or more hydroxyl groups. 3. The aqueous dispersion according to any one of claims 1 and 2, in which the nitrogen-containing compound has a molecular weight of up to 170. 4. The aqueous dispersion according to any one of claims 1 and 2, in which the nitrogen-containing compound has a molecular weight of up to 160. 5. The aqueous dispersion according to claim 1, in which the nitrogen-containing compound has one or more hydroxyl groups. 6. The aqueous dispersion according to claim 5, in which one or more hydroxyl groups are present at the end of one or more substituents of the nitrogen-containing compound. 7. The aqueous dispersion according to any one of claims 1 and 2, in which the nitrogen-containing compound is an amine. 8. An aqueous dispersion according to any one of claims 1 and 2, in which the nitrogen-containing compound is a quaternary ammonium base. 9. The aqueous dispersion according to any one of claims 1 and 2, in which the nitrogen-containing compound is diethylenetriamine, triethylenetetramine, hexamethylenediamine, diethylamine, dipropylamine, diisopropylamine, cyclohexylamine, pyrrolidine, guanidine, triethanolamine, monoethanolamine, diethanolamine, 2-methanolamine, diethanolamine, diethanolamine lysine, choline hydroxide, tetramethylammonium hydroxide or tetraethylammonium hydroxide. 10. An aqueous dispersion according to any one of claims 1 and 2, wherein the anionic polyelectrolyte is an inorganic material. 11. The aqueous dispersion of claim 10, in which the anionic polyelectrolyte is a silicon-containing material. 12. The aqueous dispersion of claim 11, wherein the anionic polyelectrolyte is bentonite. 13. The aqueous dispersion according to claim 11, in which the anionic polyelectrolyte contains particles based on silicon. 14. The aqueous dispersion according to any one of claims 1 and 2, wherein the acid anhydride is iso-octadecenyl succinic anhydride, iso-octadecyl succinic anhydride, n-hexadecenyl succinic anhydride, dodecenyl succinic anhydride, decenyl succinic anhydride, octenyl succinic anhydride, tri-isobutenyl succinic anhydride, 1-octyl-2-decenyl succinic anhydride or 1-hexyl-2-octenyl succinic anhydride. 15. The aqueous dispersion according to any one of claims 1 and 2, in which the acid anhydride is present in an amount of from 0.1 to 30 wt.% Based on the weight of the aqueous dispersion. 16. The aqueous dispersion according to any one of claims 1 and 2, in which the anionic polyelectrolyte is present in an amount of from 0.5 to 10 wt.% Based on the weight of the acid anhydride. 17. The aqueous dispersion according to any one of claims 1 and 2, in which the nitrogen-containing organic compound is present in an amount of from 0.5 to 10 wt.% Based on the weight of the acid anhydride. 18. The aqueous dispersion according to any one of claims 1 and 2, in which the dispersion further comprises an anionic surfactant. 19. The aqueous dispersion of claim 18, wherein the anionic surfactant is hydrolyzed acid anhydride. 20. A method of producing an aqueous dispersion of a cellulose-active sizing agent, which comprises dispersing an acid anhydride in the aqueous phase in the presence of an anionic polyelectrolyte and a nitrogen-containing organic compound, which is an amine or its corresponding quaternary ammonium base having a molecular weight of less than 180. 21. A method for producing an aqueous dispersion of a cellulose-active sizing agent, which comprises dispersing an acid anhydride in the aqueous phase in the presence of an anionic polyelectrolyte and a nitrogen-containing organic compound, which is an amine or its corresponding quaternary ammonium base having one or more hydroxyl groups. 22. The method according to any one of claims 20 or 21, wherein the nitrogen-containing compound has a molecular weight of up to 170. 23. The method according to any one of paragraphs.20 or 21, in which the nitrogen-containing compound has a molecular weight up to 160. 24. The method according to any one of claims 20 or 21, wherein the nitrogen-containing compound has one or more hydroxyl groups. 25. The method according to paragraph 24, in which one or more hydroxyl groups are present at the terminal site of one or more substituents of the nitrogen-containing compound. 26. The method according to any one of claims 20 or 21, wherein the nitrogen-containing compound is an amine. 27. The method according to any one of claims 20 or 21, wherein the nitrogen-containing compound is a quaternary ammonium base. 28. The method according to any one of claims 20 or 21, wherein the nitrogen-containing compound is diethylenetriamine, triethylenetetramine, hexamethylenediamine, diethylamine, dipropylamine, diisopropylamine, cyclohexylamine, pyrrolidine, guanidine, triethanolamine, monoethanolamine, diethanolamine, ethanolamine , choline hydroxide, tetramethylammonium hydroxide or tetraethylammonium hydroxide. 29. The method according to any one of claims 20 or 21, wherein the anionic polyelectrolyte is an inorganic material. 30. The method according to clause 29, in which the anionic polyelectrolyte is a silicon-containing material. 31. The method according to clause 30, in which the anionic polyelectrolyte is bentonite. 32. The method according to clause 30, in which the anionic polyelectrolyte contains particles based on silicon. 33. The method according to any one of claims 20 or 21, wherein the acid anhydride is iso-octadecenyl succinic anhydride, iso-octadecyl succinic anhydride, n-hexadecenyl succinic anhydride, dodecenyl succinic anhydride, decenyl succinic anhydride, octenyl- succinic anhydride, tri-isobutenyl succinic anhydride, 1-octyl-2-decenyl succinic anhydride or 1-hexyl-2-octenyl succinic anhydride. 34. The method according to any one of claims 20 or 21, in which the acid anhydride is present in an amount of from 0.1 to 30 wt.% Based on the weight of the aqueous dispersion. 35. The method according to any one of claims 20 or 21, in which the anionic polyelectrolyte is present in an amount of from 0.5 to 10 wt.% Based on the weight of the acid anhydride. 36. The method according to any one of claims 20 or 21, wherein the nitrogen-containing organic compound is present in an amount of from 0.5 to 10 wt.% Based on the weight of the acid anhydride. 37. The method according to any one of claims 20 or 21, in which the dispersion further comprises an anionic surfactant. 38. The method according to clause 37, in which the anionic surfactant is hydrolyzed acid anhydride. 39. The use of an aqueous dispersion of cellulose-active sizing agent according to any one of claims 1 to 19 for sizing in bulk or surface sizing in paper production. 40. A method of producing paper that comprises adding an aqueous dispersion of cellulose-active sizing agent to an aqueous suspension of cellulose and dewatering the resulting suspension on a paper machine grid or applying an aqueous dispersion of cellulose-active sizing agent to the surface of a sheet or web of cellulose, wherein the dispersion is aqueous a dispersion of cellulose-active substance according to any one of claims 1 to 19. 41. The method according to p, in which the aqueous suspension of cellulose has a conductivity of at least 2.0 MS / cm