JP4375625B2 - Dispersion - Google Patents

Abstract

The invention relates to an aqueous dispersion useful for internal sizing or surface sizing in the production of paper, comprising at least one cellulose reactive sizing agent selected from the group consisting of ketene dimers and multimers, at least one cellulose non-reactive sizing agent and at least one emulsifier selected from the group consisting of oxyalkylene phosphate and sulfate esters and salts thereof. The invention further concerns a process for its preparation, use thereof, and processes for the production of paper.

Description

  The present invention relates to an aqueous dispersion comprising a cellulose reactive sizing agent, a cellulose non-reactive sizing agent and an emulsifier, its preparation and its use in papermaking.

  Cellulose reactive sizes such as those based on alkyl ketene dimer (AKD) and alkenyl succinic anhydride (ASA) are widely used for internal sizing in papermaking. They generally give good internal sizing even at low doses. However, under certain circumstances, the efficiency of conventional cellulose-reactive sizing agents has, for example, high cation requirements and significant amounts of lipophilic wood extracts such as resin acids, fatty acids, fatty esters, triglycerides It has been experienced that it is not satisfactorily satisfactory when used in conjunction with paper stocks such as.

  It has also been suggested to use cellulose reactive sizing agents for surface sizing, but it has been found that they can cause problems due to size reversal, toner adhesion and high speed paper processing.

  Cellulose non-reactive sizes have been used so far for surface sizing. Examples of such materials are starch and other polymer sizes such as copolymers of styrene and vinyl monomers such as maleic anhydride, acrylic acid and its alkyl esters, acrylamide and the like. Cellulose non-reactive sizes generally have improved toner adhesion when compared to reactive sizes, little or no effect on coefficient of friction, no effect on high speed processing, or improved effect, and no size reversal Indicates. However, they are less effective than cellulose reactive size during sizing.

  Cellulose reactive sizes are generally provided in the form of a dispersion comprising an aqueous phase and fine particles or droplets of a sizing agent dispersed therein. These dispersions are usually combined with a high molecular weight amphoteric or cationic polymer such as cationic starch, polyamine, polyamidoamine or vinyl addition polymer with the aid of a dispersant system consisting of an anionic compound such as sodium lignosulfonate. Prepared. Depending on the total charge of the dispersant-based compound, the size dispersion will be cationic or anionic in nature.

  U.S. Pat. No. 5,690,011 discloses an improved aqueous dispersion of a cellulose reactive sizing agent dispersed in an aqueous phase by a dispersant system comprising a low molecular weight cationic organic compound and an anionic stabilizer.

  WO 02/090653 discloses a sizing composition comprising a sizing agent, a nonionic surfactant, an anionic surfactant and a monohydric alcohol.

  U.S. Pat. No. 4,529,447 is a sizing comprising a carboxylic anhydride and an alkaline earth metal salt of a polyoxyalkylene nonionic surfactant and / or a sulfur-containing anionic surfactant blocked with a lower alkyl group, an acyl group or a carbamoyl group A composition is disclosed.

  EP-A1-151646 discloses a sizing agent based on alkyl succinic anhydride.

  US Pat. No. 5,498,648 discloses a paper size mixture prepared by mixing a suspension of cationic starch with a polymer dispersion and emulsifying the alkyl diketene in this mixture. However, such formulations have been found to be predominantly cationic and interfere with anionic components used in papermaking, especially fluorescent brighteners.

  US Pat. No. 6,162,328 obtained a cellulose reactive size that is not solid at 25 ° C. and a cellulose nonreactive size, a polymer with a weight average molecular weight greater than about 1500, by sheeting and drying an aqueous pulp suspension. Disclosed is a paper manufacturing method applied to paper. However, particularly for anionic dispersions, it has proven difficult to provide highly stable dispersions containing both cellulose reactive sizes and cellulose non-reactive sizes.

  It is an object of the present invention to provide a highly stable dispersion containing a cellulose reactive sizing agent.

  Another object of the present invention is to provide a dispersion comprising a cellulose reactive sizing agent and a non-cellulose reactive sizing agent.

  Yet another object of the present invention is to provide a highly efficient size for internal sizing.

  A further object of the present invention is to provide a highly efficient size for surface sizing.

  Surprisingly, it has been found that stable dispersions of cellulose-reactive and non-reactive cellulose sizing agents can be obtained by using certain emulsifiers. Thus, the present invention provides at least one cellulose reactive sizing agent selected from the group consisting of ketene dimers and multimers, at least one cellulose non-reactive sizing agent, and oxyalkylene phosphate esters and sulfate esters (the latter is And oxyalkylene sulfonate), and at least one emulsifier selected from the group consisting of these salts (of which oxyalkylene phosphate and its salt are most preferred), It relates to aqueous dispersions useful for internal sizing or surface sizing in the manufacture of paper.

  The weight ratio of the cellulose reactive sizing agent to the cellulose non-reactive sizing agent is preferably from about 1:99 to about 99: 1, most preferably from about 1: 9 to about 9: 1. In dispersions for internal sizing, suitable for addition to paper stock containing cellulose fibers, the weight ratio is preferably from about 0.4: 1 to about 99: 1, most preferably from about 1: 1 to about In a dispersion for surface sizing, suitable for being applied to a paper web, the weight ratio is preferably from about 1:99 to about 1: 1, most preferably about 9: 1. From 1: 9 to about 1: 1.5.

  Preferably, the dispersion also includes at least one cationic organic compound having a weight average molecular weight of about 10,000 or less, at least one anionic stabilizer, or both (which is most preferred).

  In a most preferred embodiment, the dispersion is thus a cellulose reactive sizing agent, a cellulose non-reactive sizing agent and oxyalkylene phosphates and sulfates and their salts selected from the group consisting of ketene dimers and multimers. A dispersion comprising an emulsifier selected from the group consisting of: a cationic organic compound having a weight average molecular weight of about 10,000 or less; and an anionic stabilizer.

  The amount of ketene dimer and multimer in the dispersion is preferably from about 0.1 wt% to about 50 wt%, most preferably from about 0.5 wt% to about 50 wt%. It is preferred that at least one hydrophobic ketene dimer is present. Preferred ketene dimers have the general formula:

Wherein R ¹ and R ² represent the same or different saturated or unsaturated hydrocarbon groups such as alkyl, alkenyl, cycloalkyl, aryl or aralkyl.
Have The hydrocarbon group preferably has from 6 to 36 carbon atoms, most preferably from 12 to 20 carbon atoms. Examples of hydrocarbon groups include octyl, decyl, dodecyl, tetradecyl, hexadecyl, octadecyl, eicosyl, docosyl, tetracosyl, phenyl, benzyl, beta-naphthyl, cyclohexyl and hexadecyl. Is mentioned. Preferred hydrocarbon groups are linear or branched alkyl groups such as hexadecyl and octadecyl groups. Useful ketene dimers include organic acids such as montanic acid, naphthenic acid, 9,10-decylenic acid, 9,10-dodecylenic acid, palmitolic acid, oleic acid, ricinoleic acid, linoleic acid, eleostearic acid, Coconut oil, Babas oil, coconut shell oil, palm oil, olive oil, peanut oil, rapeseed oil, natural mixture of fatty acids found in beef tallow, lard, whale fat, and any one of the fatty acids listed above Also included are those prepared from mixtures.

The amount of emulsifier selected from oxyalkylene phosphates and sulfates and their salts in the dispersion is preferably from about 0.01% to about 10%, most preferably from about 0.1% to about 5% by weight. Up to. Preferred phosphate esters and sulfate esters have the formula:
R ³ -A ¹ -OQR ⁴
(Wherein R ⁴ is —OH or —O—A ² —R ⁵ ,
A ¹ and A ² are, independently of one another, preferably from about 2 to 100 oxyalkylene units, most preferably from 3 to 50 oxyalkylene units, most particularly preferably from 5 to 20 An oxyalkylene chain having an oxyalkylene unit of
Q is PO (OH) or SO ₂ , of which PO (OH) is preferred, and
R ³ and R ⁵ are, independently of one another, preferably a hydrocarbon radical having from 3 to 50 carbon atoms, most preferably from 8 to 20 carbon atoms)
to go into.

  The hydrocarbon group may be, for example, alkyl, alkenyl, cycloalkyl, aryl or aralkyl, and among them, an aliphatic group, particularly an alkyl group is preferable. The oxyalkylene chain is preferably composed of an oxyethylene unit, an oxypropylene unit or a mixture thereof, and among them, a pure oxyethylene chain is most preferable. The most preferred emulsifiers belong to the group of aliphatic mono and di (polyoxyethylene alkyl) phosphate esters having one or two oxyethylene chains, each containing 5 to 15 moles of ethylene oxide, in which case one or more Alkyl groups have 10 to 15 carbon atoms. Examples of such polyoxyethylene alkyl phosphate esters include ethoxylated tridecyl phosphate esters. Most preferably, a mixture of mono and di (polyoxyalkylene alkyl) esters of phosphoric acid is used.

  As already mentioned, the emulsifier may also be one or more salts of the above compounds, preferably ammonium or alkali metal salts such as sodium or potassium salts, but other metals such as magnesium or calcium. Other salts are also possible.

When a cationic organic compound having a weight average molecular weight of about 10,000 or less is present, its amount in the dispersion is preferably from about 0.01% to about 5%, most preferably from about 0.1% to about 2%. Up to%. The cationic organic compound preferably comprises one or more cationic groups of the same or different type, most preferably a cationic compound having one cationic group and a cationic compound having two or more cationic groups; That is, it contains a cationic polyelectrolyte. Examples of suitable cationic groups include sulfonium groups, phosphonium groups, acid addition salts of primary, secondary and tertiary amines or amino and quaternary ammonium groups, such as nitrogen quaternary with methylene chloride, dimethyl sulfate or benzyl chloride. When graded, preferred are amine / amino acid addition salts and quaternary ammonium groups. Cationic polyelectrolytes can have a degree of substitution (DS _c ) that varies over a wide range, for example, from about 0.01 to about 1.0, preferably from about 0.1 to about 0.8, and most preferably from about 0.2 to about 0.6.

Cationic organic compounds suitable for use in the present invention are cations that can function as surfactants and / or dispersants and / or coupling agents between sizing and / or anionic stabilizer particles or droplets. Containing sexual compounds. This cationic organic compound is preferably a surfactant. Preferred cationic surfactants are those of the general formula R ₄ N ⁺ X ⁻ , wherein each R group is independently of one another hydrogen or 1 to 30 carbon atoms, preferably 1 to 22 And a compound having a hydrocarbon group having a carbon atom. The hydrocarbon group is suitably an aliphatic, preferably an alkyl group, interrupted by one or more heteroatoms such as oxygen or nitrogen, and / or groups containing heteroatoms such as carbonyl and acyloxy groups. May be. At least one, preferably at least three, and preferably all of the R groups contain carbon atoms. Suitably at least one, preferably at least two, of said R groups contain at least 7 carbon atoms, preferably at least 9 carbon atoms, most preferably at least 12 carbon atoms. X ⁻ is an anion, preferably a halide ion such as a chloride ion, or a proton, for example, wherein the surfactant is of the formula R ₃ NH ⁺ , where R is as defined above. In the case of a fluorinated amine, it is an anionic group present in the anionic compound of the dispersion. Examples of suitable surfactants include dioctyldimethylammonium chloride, didecyldimethylammonium chloride, dicocodimethylammonium chloride, cocobenzyldimethylammonium chloride, coco (fractionated) benzyldimethylammonium chloride, octadecyltrimethylammonium chloride, dioctadecyldimethyl. Ammonium chloride, dihexadecyldimethylammonium chloride, di (hydrogenated tallow) dimethylammonium chloride, di (hydrogenated tallow) benzylmethylammonium chloride, (hydrogenated tallow) benzyldimethylammonium chloride, dioleyldimethylammonium chloride, and di ( Ethylene hexadecane carboxylate) dimethylammonium chloride. Particularly preferred cationic surfactants thus include those containing at least one hydrocarbon group having from 9 to 30 carbon atoms, in particular quaternary ammonium compounds.

  As useful cationic polyelectrolytes, optionally also degraded, low molecular weight cationic organic polymers such as those derived from polysaccharides such as starch and guar gum, cationic condensations such as cationic polyurethanes Products, polyamidoamines such as polyamidoamine-epichlorohydrin copolymers, polyamines such as dimethylamine-epichlorohydrin copolymers, dimethylamine-ethylenediamine-epichlorohydrin copolymers, ammonia-ethylene dichloride copolymers, cationic groups Vinyl addition polymers formed from monomers having, for example, diallyldimethylammonium chloride, dialkylaminoalkyl acrylates, methacrylates and acrylamides (eg dimethylaminoethyl acrylate) Homopolymers and copolymers) (which are usually optionally copolymerized with nonionic monomers including acrylamide, alkyl acrylates, styrene and acrylonitrile and derivatives of such monomers, vinyl esters, etc., Existing as an addition salt or a quaternary ammonium salt).

  The cationic organic compound may generally have a weight average molecular weight of up to about 10,000, usually up to about 5000, suitably up to about 3000, preferably up to about 800, most preferably at least about 200. Suitable cationic surfactants preferably have a weight average molecular weight of up to about 3000, most preferably from about 200 to about 800.

When an anionic stabilizer is present, its amount in the dispersion is preferably from about 0.01% to about 5%, most preferably from about 0.1% to about 3% by weight. As anionic stabilizers suitable for use in the present invention, only anionic compounds that function as stabilizers and / or are effective in combination with the above cationic organic compounds to stabilize the sizing agent in the aqueous phase. And anionic compounds known to be useful as dispersants in the preparation of size dispersions. This anionic compound is preferably water-soluble or water-dispersible. The anionic stabilizer may be selected from organic or inorganic compounds and may be derived from natural or synthetic sources. The dispersant-based anionic stabilizer includes one or more anionic groups of the same or different types, and includes an anionic compound having one anionic group and an anionic compound having two or more anionic groups (this (Referred to as an anionic polyelectrolyte in the specification). The term anionic polyelectrolyte is also meant to include anionic compounds that act as polyelectrolytes, for example, by chemical nonionic interactions or suction. In a preferred embodiment, the anionic stabilizer is an anionic polyelectrolyte. Examples of suitable anionic groups, ie groups that are anionic or rendered anionic in water, include phosphate groups, phosphonate groups, sulfate groups, sulfonate groups, sulfonic acid groups and carboxylic acid groups and their salts, Usually, an ammonium salt or an alkali metal (generally sodium) salt is used. These anionic groups may be natural or may be introduced by chemical modification in a known manner. The anionic stabilizer can have an anionic substitution degree (DS _A ) that varies over a wide range. The DS _A from 0.01 to 1.4, preferably from 0.1 to 1.2, preferably may be from 0.2 to 1.0. An anionic polyelectrolyte may contain one or more cationic groups as long as it has an anionic total charge.

  In a preferred embodiment, the anionic stabilizer is selected from organic compounds. Suitable anionic stabilizers of this type include polymeric compounds such as those based on polysaccharides such as lignin or starch, guar gum, cellulose, chitin, chitosan, glycans, galactans, glucans, xanthan gums, mannans, dextrins, etc. Preferably not only phosphorylated, sulfonated or carboxylated lignin or polysaccharide, but also condensation products such as anionic polymer compounds based on anionic polyurethane and naphthalene, such as condensed naphthalene sulfonate, and anionic groups. Further monomers produced from, for example, acrylic acid, methacrylic acid, maleic acid, itaconic acid, crotonic acid, vinyl sulfonic acid, sulfonated styrene and hydroxyalkyl acrylate and methacrylate phosphates Synthetic organic polymers such as vinyl addition polymers (optionally copolymerized with nonionic monomers including acrylamide, alkyl acrylate, styrene and acrylonitrile as well as derivatives of such monomers, vinyl esters, etc.) It is done. Particularly preferred organic anionic stabilizers are based on anionic polysaccharides, for example cellulose derivatives such as carboxymethylcellulose, condensed naphthalene or lignin sulfonate, anionic acrylamide-based polymers and acrylic acid and similar acid monomers. Polymers.

  In one embodiment of the invention, the anionic stabilizer is a hydrophobically modified polysaccharide containing one or more hydrophobic groups, suitably hydrophobically modified polysaccharide, preferably carboxymethylcellulose. Examples of suitable groups include hydrophobic substituents containing from 4 to about 30 carbon atoms, especially saturated or unsaturated hydrocarbon chains of at least 4 and preferably 8 to 30 carbon atoms Hydrophobic amide substituents, ester substituents and ether substituents optionally interrupted by one or more heteroatoms, for example oxygen or nitrogen, and / or groups containing heteroatoms, carbonyl or acyloxy Is mentioned.

  When the anionic stabilizer is an organic compound or polymer, its weight average molecular weight is preferably about 200 or more, most preferably 500 or more, but preferably 50,000 or less.

  In another embodiment, the anionic stabilizer is an inorganic anionic material, preferably an anionic inorganic polyelectrolyte, such as a compound containing a silicon atom, such as various forms of condensed or polymerized silica having a negative hydroxyl group. Acids such as oligomeric silicic acid, polysilicic acid, polysilicate and polyaluminum silicate are selected.

  Anionic stabilizers may also be selected from particulate materials, in which case both organic and inorganic anionic materials are included. Suitable particulate materials of this type include highly crosslinked anionic vinyl addition polymers such as acrylamide-based polymers and acrylate-based polymers, anionic condensation polymers such as melamine-sulfonic acid sols, inorganic Silica-based materials such as silica sols, aluminate-treated silica sols, aluminum silicate sols, polysilicate microgels and polyaluminum silicate microgels, as well as aqueous silica-based sols such as silica gel and precipitated silica The type of material present in it. The particulate material is preferably a colloid, ie, a colloidal range of particle size. These colloidal particles suitably have a particle size of about 1 nm to about 40 nm, preferably 2 nm to 35 nm, most preferably 2 nm to 10 nm.

  The cellulose non-reactive sizing agent is preferably present in the dispersion in an amount from about 0.1% to about 50%, most preferably from about 0.5% to about 50% by weight. Suitable cellulose non-reactive sizing agents are preferably polymeric materials having a weight average molecular weight of greater than 50000, most preferably from 50000 to about 1000000. This polymeric material is preferably made from an ethylenically unsaturated monomer.

  Particularly suitable polymers include copolymers of styrene or substituted styrene and at least one other type of ethylenically unsaturated monomer, preferably comprising a monomer containing one or more carboxyl groups. Examples of such monomers include not only maleic anhydride, acrylic acid, methacrylic acid and itaconic acid, but also their esters, amides and nitriles, of which esters are particularly preferred. Preferred esters are alkyl esters whose alkyl groups preferably have from 1 to 12 carbon atoms, most preferably from 1 to 5 carbon atoms. Particularly preferred are esters of acrylic acid or methacrylic acid. Examples of suitable alkyl groups are methyl, ethyl, propyl, n-butyl, iso-butyl, tert-butyl and 2-butyl. Particularly preferred are mixtures of at least two isomeric butyl acrylates or methacrylates, for example n-butyl acrylate or n-butyl methacrylate and t-butyl acrylate or t-butyl methacrylate. The monomer may also be copolymerized with other ethylenically unsaturated monomers.

  In a preferred embodiment, the non-cellulose reactive sizing agent is from about 20% to about 80%, preferably from about 30% to about 70% by weight styrene or substituted styrene, from about 20% to about 80%. %, Preferably about 30% to about 70% by weight of alkyl acrylate or methacrylate, and 0% to about 15% by weight, preferably 0% to about 10% by weight of other ethylenic unsaturations It is a copolymer obtained from an ethylenically unsaturated monomer containing monomer.

  The dispersion of the present invention may also contain other components such as one or more bactericides, antifoaming agents, inorganic compounds such as aluminum compounds or zirconium compounds.

  The dispersion of the present invention is preferably mainly anionic, which reduces the risk of interference with anionic components used in papermaking. The pH is preferably from about 2 to about 6, most preferably from about 3 to about 5, which improves, for example, the stability of ketene dimers. This viscosity is preferably from about 1 mPas to about 300 mPas, most preferably from about 5 mPas to about 100 mPas. This dry content is preferably from about 1% to about 50% by weight, most preferably from about 5% to about 40% by weight.

  It has been found that it is possible to provide a dispersion according to the invention having a low viscosity, in which case both static storage stability and thermal stability are excellent. Furthermore, the dispersion of the present invention was found to be very effective for both internal sizing and surface sizing during papermaking.

  As used herein, the term “paper” is meant to include not only regular paper, but also any type of cellulose-based product in sheet or web form, including, for example, board and paperboard. However, the present invention is particularly advantageous for the preparation of photographic paper used in all kinds of printing methods, for example ink jet printing, laser printing, copying and the like.

  The invention also relates to a method for preparing the dispersion. The method comprises at least one cellulose reactive sizing agent selected from the group consisting of ketene dimers and multimers, at least one cellulose non-reactive sizing agent, oxyalkylene phosphate ester and sulfuric acid in the presence of water. A step of obtaining a mixture by combining at least one emulsifier selected from the group consisting of esters and salts thereof, and a step of obtaining an aqueous dispersion by homogenizing the mixture. The temperature during homogenization is preferably high enough for the cellulose reactive sizing agent to be liquid, and in most cases is preferably from about 20 ° C to about 100 ° C, most preferably from about 50 ° C to about 95 ° C. It is. The cellulose non-reactive sizing agent may be an aqueous dispersion such as a commercially available cellulose non-reactive size such as Trademark Jet Size® AE27, AE35 and AE76 (Eka Chemicals AB), Vasoplast® 400DS. (BASF), a dispersion of poly (styrene / acrylate) commercially available as Perglutin® A281 (Giulini), or preferably in the form of a dispersion described in US Pat. Furthermore, it is preferred to also add a cationic organic compound or anionic stabilizer having a weight average molecular weight of about 10,000 or less, or both (which is most preferred) prior to homogenization. With regard to suitable and preferred variants of these components and their amounts, reference is made to the previous description of the dispersion itself.

The present invention further includes the use of the dispersion of the present invention for paper surface sizing, the step of forming the paper web from a stock containing cellulose fibers, and the aqueous dispersion of the present invention applied to the surface of the paper web. The present invention relates to a paper manufacturing method including a process. The dispersion may be applied to the paper web in a size press or other suitable apparatus by any known method, and is preferably included in the size press. The dispersion of the present invention is preferably supplied to the paper in an amount from about 0.05% to about 20% by weight, preferably from about 0.1% to about 10% by weight, based on the amount of paper produced. . In addition, the size press solution may contain one or more of the following components: preferably an optical brightener in an amount of about 0% to about 2% by weight of the amount of paper produced, preferably about 0 g of the paper produced. / amount of pigment from m ² to about 15 g / m ² (e.g., chalk, precipitated calcium carbonate, kaolin, titanium dioxide, barium sulphate or gypsum), preferably about from about 0 g / m ² paper produced 5 g / It is possible to supply starch, cross-linking agents such as zirconium compounds, insolubilizing agents, antifoaming agents, etc. up to m ² .

  The present invention further includes the use of the dispersion of the present invention for internal sizing during paper manufacture, the step of adding the dispersion of the present invention to a stock containing cellulose fibers, and dewatering the stock on a wire. Thus, the present invention relates to a paper manufacturing method including a step of obtaining paper and white water. The dispersion may be added separately or may be premixed with one or more other additives such as a retention aid.

  The stock preferably comprises from about 50% to about 100% by weight, most preferably from about 70% to about 100% by weight of cellulose fibers, based on dry stock. The stock is also one or more fillers such as kaolin, china clay, titanium dioxide, gypsum, talc, chalk, ground marble or precipitated calcium carbonate, and other commonly used if necessary. It is preferable to contain an additive, for example, a yield aid, an aluminum compound, a dye, a wet strength enhancing resin, a fluorescent brightening agent and the like. Examples of aluminum compounds include alum, aluminate and polyaluminum compounds such as polyaluminum chloride and polyaluminum sulfate. Examples of retention aids are based on cationic polymers, anionic inorganic materials in combination with organic polymers, for example bentonite in combination with cationic polymers, cationic polymers or silicas in combination with cationic polymers and anionic polymers Sol may be mentioned.

  In the dispersion of the present invention, the total amount of added cellulose reactive sizing agent is from about 0.01% to about 10%, most preferably from about 0.03% to about 5% by weight of the paper produced, On the other hand, the total amount of cellulose non-reactive sizing agent added is preferably from about 0.01% to about 10%, most preferably from about 0.03% to about 5% by weight of the paper produced. It is preferably added to the stock and / or paper web in an amount. The exact amount depends on the quality of the pulp and the level of sizing desired.

  It has been found that by using the dispersion of the present invention, the sizing effect compared to the normal size use is improved at a corresponding dose of cellulose reactive sizing agent. The possibility of using a small amount of sizing agent to obtain the desired level of sizing reduces the risk of accumulation of unadsorbed sizing agent in the white water circulating in the process, thereby agglomerating the sizing agent in the paper machine And reduce the risk of adhesion. Thus, the present invention provides for example 1 ton of dry paper from which 0 to 30 tonnes of fresh water is produced, usually 20 tons or less, preferably 15 tons or less, preferably 10 tons or less, most preferably 5 tons or less. It is particularly advantageous for the process with a high degree of white water sealing used per hit. In addition, the present invention provides fast on-machine sizing and very uniform sizing. Furthermore, the dispersion hardly interferes with the strong anionic components present in the papermaking process and therefore does not reduce the effectiveness of, for example, the optical brightener.

  The invention will now be further described in connection with the following examples, which are not intended to limit the scope of the invention. Unless otherwise stated, all parts and percentages represent parts by weight and percentages by weight.

An anionic aqueous sizing dispersion of the present invention was prepared from the following formulation for a 1 kg dispersion.
AKD (alkyl ketene dimer) (Kiwax (registered trademark) SF100, Eka Chemicals) 60g
115 g of aqueous dispersion of poly (styrene / acrylic ester) (Jet Size (registered trademark) AE76, Eka Chemicals)
Di beef tallow dimethylammonium chloride (Arkad ^TM 2HT-75PG, Akzo Noble) 2.75g
Polyoxyethylene phosphate ester (Rodafac ^TM RS-710, Rhodia) 4.5g
Condensed sodium naphthalenesulfonate formaldehyde condensate (Orotan ^TM SN, Rohm and Haas) 3.6g
Water: The balance up to 1000g.

  Di-tallow dimethylammonium chloride is mixed with molten alkyl ketene dimer at 70 ° C. and the mixture is poly (styrene / acrylic ester) (which was preblended with polyoxyethylene phosphate and condensed sodium naphthalene sulfonate) And passed through a homogenizer in the presence of the dispersion.

The dispersion was used for internal sizing in a pilot plant paper machine that produces paper from a premium paper furnish containing 15% ground calcium carbonate (Hydrocarb ^TM 50BG GCC, Omuya) and 0.6% optical brightener. . The yield system used was 0.5% cationic potato starch (Hi-Cat ^™ 142, rocket) and 0.3% anionic silica sol (Eka ^™ NP 442, Eka Chemicals). For comparison, paper was produced under the same conditions, but sized with the usual AKD dispersion Keydim® C (Eka Chemicals). These papers were tested for water absorption according to Cobb 60 (Tappi test method T 441 om-90) and ink resistance according to HST 80 (Tappi test method T 530 pm-89). These results are shown in the table below.

  It is clear that the dispersions according to the invention give a sizing that is considerably improved over the usual AKD-based sizes.

In the same manner as in Example 1, the dispersion of the present invention was treated with 30 g of Keywax (registered trademark) SF100, 200 g of jet size (registered trademark) AE76, 4.8 g of Arcad ^TM 2HT-75PG, 6.3 g of Rhodafak ^TM RS-710, Orotan ^TM SN Prepared from 6.3 g and water (amount to 1000 g). ASA (Lacer® 220) as an internal sizing agent in an amount of 0.75 kg per ton of paper from a high grade paper furnish containing 18% ground calcium carbonate (Hydrocarb ^TM 50BG GCC, Omuya). Used for surface sizing of internally pre-sized paper (Cobb60 = 37 g / m ² ) manufactured by Eka Chemicals. The basis weight was 80 g / m ^2. The yield system was 0.5% cationic potato starch (Hi-Cat ^™ 142, rocket) and 0.5% anionic silica sol (Eka ^™ NP 780, Eka Chemicals). In addition, 0.6% optical brightener was added to the stock. The dispersion of the invention was added to a size press along with potato starch oxygenated at 5% solids (Perfectamil ^TM P 255 SH, Abebe). For comparison, the same type of paper was surface sized with a normal surface size based on a styrene acrylate copolymer dispersion (Jet Size® AE76, Eka Chemicals) under the same conditions. These papers were tested for water absorption according to Cobb 60 and ink resistance according to HST80. These results are shown in the table below.

* Active ingredient represents total amount of alkyl ketene dimer and styrene acrylate copolymer.

  It is clear that the dispersions of the present invention provide sizing that is significantly improved over normal surface sizes.

  Dispersions were prepared in the same manner as in Example 1 and samples were stored in bottles for 5 weeks and then tested for static storage stability by measuring dry content at the top and bottom of the bottle. These formulations (for 1 kg of dispersion) and results are shown in the table below.

  It is clear that the sample without polyoxyethylene phosphate had already separated into two phases after 5 weeks of storage.

  A dispersion was prepared in the same manner as in Example 1 and the samples were shaken at 250 rpm and 30 ° C. for 10 days and tested for thermal stability by measuring the particle size distribution. These formulations (for 1 kg of dispersion) and results are shown in the table below. The numerical values for particle size represent the particle size in which 50% and 90% by volume, respectively, of the particles in each sample are smaller. Thus, in formulation (1) after 10 days, 50% of the particles were smaller than 0.59 μm and 90% were smaller than 0.92 μm.

Claims (13)

At least one cellulose-reactive sizing agent selected from the group consisting of ketene dimers of the following formula (1):

(Wherein R ¹ and R ² represent the same or different saturated or unsaturated hydrocarbon groups),
From the group consisting of copolymers of styrene or substituted styrene with maleic anhydride, acrylic acid, methacrylic acid, itaconic acid and their esters, amides and at least one other type of ethylenically unsaturated monomer selected from the group consisting of nitriles Internal sizing in the manufacture of paper, characterized in that it comprises at least one cellulose non-reactive sizing agent selected and at least one emulsifier selected from the group consisting of oxyalkylene phosphates and oxyalkylene phosphates Aqueous dispersion useful for surface sizing. It has a weight average molecular weight of 10,000 or less and has the general formula R ₄ N ⁺ X ⁻
Wherein each R group is independently of one another hydrogen or a hydrocarbon group having from 1 to 30 carbon atoms, and X is an anion.
The dispersion according to claim 1, further comprising at least one cationic organic compound which is a surfactant selected from the group consisting of compounds having the formula: The dispersion according to any one of claims 1 to 2, further comprising at least one anionic stabilizer selected from the group consisting of condensed naphthalene and lignin sulfonate. The oxyalkylene phosphate ester has the formula:
R ³ -A ¹ -OQR ⁴
(Wherein R ⁴ is —OH or —O—A ² —R ⁵ , A ¹ and A ² are each independently an oxyalkylene chain, and Q is PO (OH) or SO ₂ . And R ³ and R ⁵ are each independently a hydrocarbon group)
The dispersion according to any one of claims 1 to 3, wherein The dispersion according to any one of claims 1 to 4, wherein the at least one other type of ethylenically unsaturated monomer is selected from the group consisting of alkyl esters of acrylic acid or methacrylic acid. The dispersion according to any one of claims 1 to 5, wherein the dispersion is mainly anionic. The dispersion according to any one of claims 1 to 6, wherein the pH is 2 to 6. In the presence of water, at least one cellulose-reactive sizing agent selected from the group consisting of ketene dimers of the following formula (2):

(Wherein R ¹ and R ² represent the same or different saturated or unsaturated hydrocarbon groups),
From the group consisting of copolymers of styrene or substituted styrene with maleic anhydride, acrylic acid, methacrylic acid, itaconic acid and their esters, amides and at least one other type of ethylenically unsaturated monomer selected from the group consisting of nitriles A step of combining at least one cellulose non-reactive sizing agent selected and at least one emulsifier selected from the group consisting of oxyalkylene phosphates and oxyalkylene phosphates , and homogenizing the mixture The method for preparing a dispersion according to any one of claims 1 to 7, further comprising a step of obtaining an aqueous dispersion. 9. The method of claim 8, further comprising adding a cationic organic compound having a weight average molecular weight of 10,000 or less and an anionic stabilizer prior to homogenizing the mixture. Use of the dispersion according to any one of claims 1 to 7 for surface sizing of paper. Use of the dispersion according to any one of claims 1 to 7 for internal sizing during paper manufacture. A paper manufacturing method comprising: forming a paper web from a stock containing cellulose fibers; and applying the aqueous dispersion according to any one of claims 1 to 7 to the surface of the paper web. Method. A step of adding the dispersion according to any one of claims 1 to 7 to a stock containing cellulose fibers, and a step of dehydrating the stock on a wire to obtain paper and white water. A paper manufacturing method.