ES2385766T3 - Coating or agglutination formulations of paper and methods for making and using them - Google Patents

Abstract

A paper coating or agglutination formulation, comprising: an aqueous polymer dispersion comprising a copolymer obtained by polymerization of an unsaturated monomer and a carbohydrate derived compound having a dextrose equivalent (DE) of 10 to 35; and a tetrasulfonate based fluorescent bleaching agent.

Description

Coating or agglutination formulations of paper and methods for making and using them

TECHNICAL FIELD

This invention relates to paper coating or agglutination formulations and more particularly to aqueous polymer dispersions and methods for making and using them in paper coating and agglutination formulations.

BACKGROUND

In the production of paper such as sheets of paper, cardboard and cardboard, it is often important to provide a product with desirable aesthetic properties. For example, paper that is white and / or glossy is more attractive to the consumer and provides a greater contrast with the ink or other media provided thereon than paper that is less white or glossy. Typically, the fibers used to form the paper are impregnated or coated with a binder composition that includes a polymer latex and one or more fibers that provide the desired whiteness or gloss of the paper.

One type of filler that is used to provide the desired whiteness or brightness of the paper includes fluorescent bleaching agents or FWA. Fluorescent bleaching agents may be based, for example, on sulphonated stilbene derivatives. In paper coating or agglutination formulations, fluorescent bleaching agents are provided with "activators" or "carriers" to provide the desired bleaching effects of fluorescent bleaching agents on paper. The publication of Bayer Blankophor® P liquid / Blankophor® P150 liquid Fluorescent Whitening Agents describes the use of polyvinyl alcohol (PVOH) and carboxymethylcellulose (CMC) as carriers for use with fluorescent bleaching agents. However, the presence of these carriers or activators increases the viscosity of the coating or agglutination formulation and also increases the cost of the formulation.

WO 01/11139 A, EP 0 806 522 A and EP 0 408 099 A disclose paper binder compositions comprising copolymers obtained by polymerization of an unsaturated monomer and a dextrin compound. US 2002/260509 generally discloses a binder composition comprising a fluorescent bleaching agent.

SUMMARY

A paper coating or agglutination formulation comprises an aqueous polymer dispersion comprising a copolymer obtained by polymerization of an unsaturated monomer and a carbohydrate derived compound having a dextrose equivalent (DE) of about 10 to about 35; and a tetrasulfonate based fluorescent bleaching agent. The carbohydrate-derived compound can have a molecular weight of about 3000 to about 20,000 and can be selected from the group consisting of dextrins, maltodextrins and mixtures thereof. The copolymer can be a pure acrylic copolymer, a styrenic-acrylic copolymer, a styrene-butadiene copolymer or a vinyl-acrylic copolymer. The copolymer can be derived from about 5 to about 45 percent by weight of the carbohydrate derived compound based on the total weight of monomers. In some embodiments, the fluorescent bleaching agent is not activated. The formulation may be substantially free of polyvinyl alcohol, carboxymethyl cellulose, polyvinylpyrrolidone and water insoluble starches.

One method of preparing a paper coating or agglutination formulation includes polymerizing a mixture of an unsaturated monomer and a carbohydrate-derived compound having a dextrose equivalent (DE) of about 10 to about 35, in an aqueous medium to produce a copolymer. in an aqueous polymer dispersion; and mixing the aqueous polymer dispersion with a tetrasulfonate-based fluorescent bleaching agent. The carbohydrate-derived compound can be selected from the group consisting of dextrins, maltodextrins and mixtures thereof.

One method of improving the bleaching properties of the paper includes providing an aqueous polymer dispersion comprising a copolymer obtained by polymerization of an unsaturated monomer and a carbohydrate-derived compound having a dextrose equivalent (DE) of about 10 to about 35; mixing the aqueous polymer dispersion with a tetrasulfonate-based fluorescent bleaching agent to produce a paper coating or agglutination formulation; and apply the formulation as a paper coating. The aqueous polymer dispersion can be provided by polymerizing a mixture of an unsaturated monomer and a carbohydrate-derived compound having a dextrose equivalent (DE) of about 10 to about 35, in an aqueous medium to produce the copolymer. The carbohydrate-derived compound can be selected from the group consisting of dextrins, maltodextrins and mixtures thereof.

In addition, the paper, such as sheets of paper, cardboard or cardboard, comprises a fibrous matrix and a binder composition comprising a copolymer obtained by polymerization of an unsaturated monomer and a carbohydrate-derived compound having a dextrose equivalent (DE) from about 10 to about 35 and / or a molecular weight of about 3000 to about 20,000, and a tetrasulfonate-based fluorescent bleaching agent. The carbohydrate-derived compound can be selected from the group consisting of dextrins, maltodextrins and mixtures thereof. The binder can be provided as a coating layer on a paper substrate.

Paper coating or agglutination formulations provide rheology improvements such as circulation capacity over the coating equipment and low cost while maintaining desirable paper whitening. It was unexpected that a copolymer derived from an unsaturated monomer and a carbohydrate derived compound having the ED or molecular weight described herein would provide desirable bleaching of the paper even to levels comparable to those obtained when used in the carrier formulation or activators

Details of one or more embodiments are indicated in the accompanying drawings and subsequent description. Other features, objectives and advantages will be apparent from the description and drawings, and from the claims.

DESCRIPTION OF THE DRAWINGS

Figure 1 is a graph showing the CIE brightness of paper sheet samples free of mechanical paper pulp including and excluding UV light.

Figure 2 is a graph showing the CIE brightness with UV included minus the CIE brightness with UV excluded from paper sheet samples free of mechanical paper pulp.

Figure 3 is a graph showing the TAPPI brightness of paper sheet samples free of mechanical pulp.

Figure 4 is a graph showing the Prufbau Ósset for samples of paper sheets free of mechanical pulp.

Figure 5 is a graph showing the Repeated ("Picking") in Dry IGT in feet / min for samples of paper sheets free of mechanical paper pulp.

Figure 6 is a graph showing Prufbau's Wet Repellent of paper sheet samples free of mechanical pulp.

Figure 7 is a graph showing the TAPPI brightness of cardboard samples.

Figure 8 is a graph showing the CIE brightness with UV included minus the CIE brightness with UV excluded from formulations applied to glass with a reverse side of paper.

Similar reference symbols in the various drawings indicate similar elements.

DETAILED DESCRIPTION

The term "comprising" and its variations, as used herein, are used synonymously with the term "including" and its variations and are non-limiting open terms. The term "paper", as used herein, includes free sheets of mechanical paper pulp, cardboard, cardboard and the like.

A paper coating or agglutination formulation comprises an aqueous polymer dispersion and a tetrasulfonate-based fluorescent bleaching agent. The aqueous polymer dispersion comprises a copolymer obtained by polymerization of one or more unsaturated monomers and a carbohydrate-derived compound. The aqueous polymer dispersion includes, as the dispersed phase, particles of the copolymer that includes the carbohydrate-derived compound dispersed in an aqueous dispersion medium or aqueous phase. The aqueous polymer dispersion may include the copolymer in an amount of 40-75% solids.

The copolymer can be a pure acrylic copolymer, a styrenic-acrylic copolymer, a styrenebutadiene copolymer or a vinyl-acrylic copolymer. Unsaturated monomers suitable for use in the formation of the copolymer are generally ethylenically unsaturated monomers and include vinylaromatic compounds (eg styrene, a-methylstyrene, o-chlorostyrene and vinyltoluenes); 1,2-butadiene (ie butadiene); conjugated dienes (eg 1,3-butadiene and isoprene); mono- and dicarboxylic acids a, �-monoethylenically unsaturated or their anhydrides (e.g.

ex. acrylic acid, methacrylic acid, crotonic acid, dimethacrylic acid, ethylacrylic acid, allylacetic acid, vinylacetic acid, maleic acid, fumaric acid, itaconic acid, mesaconic acid, methylenemalonic acid, citraconic acid, maleic anhydride, itaconic anhydride and methylmalonic anhydride); mono- and mono-ethylenically unsaturated mono-and dicarboxylic acid esters having 3 to 6 carbon atoms with alkanols having 1 to 12 carbon atoms (eg esters of acrylic acid, methacrylic acid, maleic acid, fumaric acid or itaconic acid, with C1-C12, C1-C8 or C1-C4 alkanols such as acrylates and methacrylates of ethyl, n-butyl, isobutyl and 2-ethylhexyl, dimethyl maleate and n-butyl maleate); alkyl substituted acrylamides and acrylamides (eg (meth) acrylamide, N-tert-butylacrylamide and N-methyl (meth) acrylamide); (meth) acrylonitrile; vinyl halides and vinylidene (eg vinyl chloride and vinylidene chloride); vinyl esters of C1-C18 mono- or dicarboxylic acids (eg vinyl acetate, vinyl propionate, vinyl n-butyrate, vinyl laurate and vinyl stearate); C1-C4 hydroxyalkyl esters of C3-C6 mono- or di-carboxylic acids, especially acrylic, methacrylic acid or maleic acid, or their alkoxylated derivatives with from 2 to 50 moles of ethylene oxide, propylene oxide, butylene oxide or their mixtures,

or esters of these acids with alkoxylated C1-C18 alcohols with 2 to 50 moles of ethylene oxide, propylene oxide, butylene oxide or mixtures thereof (eg hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate and methyl polyglycol acrylate); and monomers containing glycidyl groups (eg glycidyl methacrylate).

Additional monomers that can be used include linear 1-olefins, branched 1-olefins or cyclic olefins (eg, ethene, propene, butene, isobutene, pentene, cyclopentene, hexene and cyclohexene); vinyl- and allyl ethers having 1 to 40 carbon atoms in the alkyl radical, wherein the alkyl radical possibly supports additional substituents such as a hydroxyl group, an amino or dialkylamino group, or one or more alkoxylated groups (e.g. eg methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, isobutyl vinyl ether, 2-ethylhexyl vinyl ether, vinyl cyclohexyl ether, vinyl 4-hydroxybutyl ether, decyl vinyl ether, dodecyl vinyl ether, octadecyl vinyl ether, 2- (diethylamino) ethyl vinyl ether, 2- (di-n-butylamino) ethyl vinyl ether, methyldiglycol vinyl ether and the corresponding allyl ethers); sulfofunctional monomers (eg allylsulfonic acid, metalylsulfonic acid, styrenesulfonate, vinyl sulfonic acid, allyloxybenzenesulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid and their corresponding alkali metal or ammonium salts, sulfopropyl acrylate and sulfopropyl methacrylate); vinyl phosphonic acid, dimethyl vinyl phosphonate and other phosphorus monomers; (meth) alkylaminoalkyl acrylates or alkylaminoalkyl (meth) acrylamides or their quaternization products

(p.

 ex. 2- (N, N-dimethylamino) ethyl acrylate, 3- (N, N-dimethylamino) propyl (ac) acrylate, 2- (N, N, N-trimethylammonium) (meth) acrylate chloride ethyl, 2-dimethylaminoethyl (meth) acrylamide, 3-dimethylaminopropyl (meth) acrylamide and 3-trimethylammoniopropyl (meth) acrylamide chloride); allyl esters of C1-C30 monocarboxylic acids; N-vinyl compounds

(p.

 ex. N-vinylformamide, N-vinyl-N-methylformamide, N-vinyl pyrrolidone, N-vinylimidazol, 1-vinyl-2-methylimidazole, 1-vinyl-2-methylimidazoline, N-vinylcaprolactam, vinylcarbazole, 2-vinylpyridine and 4-vinylpyridine; monomers containing 1,3-diketo (eg (meth) acetoacetoxyethyl or diacetone acrylamide acrylate groups; monomers containing urea groups (eg, ureidoethyl (meth) acrylate, acrylamidoglycolic acid and methacrylamidoglycolate-methyl ether); and monomers containing silyl groups (eg trimethoxysilylpropyl methacrylate).

The monomers may also include one or more crosslinkers such as N-alkylamides of carboxylic acids to, -monoethylenically unsaturated having 3 to 10 carbon atoms and their esters with alcohols having 1 to 4 carbon atoms (eg. N-methylolacrylamide and N-methylolmethacrylamide); glyoxal based crosslinkers; monomers containing two vinyl radicals; monomers containing two vinylidene radicals; and monomers containing two alkenyl radicals. Exemplary crosslinking monomers include diesters of dihydroxylated alcohols with mono-carboxylic acids, monoethylenically unsaturated acids, of which acrylic acid and methacrylic acid can be used. Examples of such monomers containing two unconjugated ethylenically unsaturated double bonds are alkylene glycol diacrylates and dimethacrylates, such as ethylene glycol diacrylate, 1,3-butylene glycol diacrylate, 1,4-butylene glycol diacrylate and propylene glycol diacrylate, divinyl benzene, methacrylate Vinyl, vinyl acrylate, allyl methacrylate, allyl acrylate, diallyl maleate, diallyl fumarate and methylene bisacrylamide. In some embodiments, crosslinking monomers include alkylene glycol diacrylates and dimethacrylates, and / or divinylbenzene. Crosslinking monomers, when used in the copolymer, may be present in an amount of 0.2% to 5% by weight based on the total weight of monomers and are considered part of the total amount of monomers used in the copolymer.

In addition to crosslinking monomers, small amounts (eg, 0.01 to 4% by weight based on the total weight of monomers) of molecular weight regulators, such as tert-dodecylmercaptane, can be added. Such substances are preferably added to the polymerization zone in a mixture with the monomers to be polymerized and are considered part of the total amount of unsaturated monomers used in the copolymer.

In some embodiments, unsaturated monomers may include styrene, a-methylstyrene, (meth) acrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, (meth) methyl acrylate, (meth) ethyl acrylate, (meth) n-butyl acrylate, (meth) isobutyl acrylate, (meth) tert-butyl acrylate, (meth) 2-ethylhexyl acrylate, vinyl acetate, butadiene, (meth) acrylamide, (meth) acrylonitrile, (meth) hydroxyethyl acrylate and glycidyl (meth) acrylate.

In some embodiments, the copolymer may be a styrenic-acrylic copolymer derived from monomers that include styrene, (meth) acrylic acid, esters of (meth) acrylic acid, (meth) acrylamide, (meth) acrylonitrile and mixtures thereof. For example, the styrenic-acrylic copolymer can include styrene and at least one of (meth) acrylic acid, itaconic acid, (meth) methyl acrylate, (meth) ethyl acrylate, (meth) n-butyl acrylate, (meth ) isobutyl acrylate,

tert-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, (meth) acrylamide, (meth) acrylonitrile and (meth) hydroxyethyl acrylate. The styrenic-acrylic copolymer can include 39 to 69% by weight of (meth) acrylates, 30 to 60% by weight of styrene, 0 to 3% by weight of (meth) acrylamide and 0 to 10% by weight of (meth) acrylonitrile. The styrenic-acrylic copolymer can also include 0 to 5% by weight of one or more crosslinking monomers such as those described above, such as alkylene glycol diacrylates and dimethacrylates.

In some embodiments, the copolymer may be a styrene-butadiene copolymer derived from monomers including styrene, butadiene, (meth) acrylamide, (meth) acrylonitrile, itaconic acid and (meth) acrylic acid. The styrene-butadiene copolymer can include from 40 to 75% by weight of styrene, from 25 to 60% by weight of butadiene, from 1 to 10% of itaconic acid and / or (meth) acrylic, from 0 to 3% in weight of (meth) acrylamide and 0 to 20% by weight of (meth) acrylonitrile. The styrene-butadiene copolymer can also include 0 to 5% by weight of one or more crosslinking monomers such as those described above, such as divinylbenzene.

In some embodiments, the copolymer is derived from unsaturated monomers in an amount of more than about 60 to less than 100% by weight, from about 62 to about 95% by weight, from about 65 to about 92% by weight or about 70 to about 85% by weight, based on the total weight of monomers (or weight of dry polymer on paper).

In addition to unsaturated monomers, the copolymer is formed by a carbohydrate-derived compound. The carbohydrate-derived compound may have a dextrose equivalent (ED) of about 10 to about 35, about 12.5 to about 25, or about 15 to about 20. The DE value can be determined according to Lane's test method. and Eynon (International Standard ISO 5377: 1981). The weight average molecular weight (Mw) of the carbohydrate-derived compound may be from about 3000 to about 20,000, from about 5000 to about 17,000 or from about 8,000 to about 14,000. The carbohydrate-derived compound can be soluble in water at room temperature in an amount of more than about 40%, more than about 50% or more than about 60% by weight, or it can even be completely soluble in water at room temperature. Solutions of the carbohydrate-derived compound in an amount of 50% by weight in water at room temperature may have a viscosity of 100 to 1000 cp or 200 to 500 cp.

In some embodiments, the carbohydrate-derived compound may include dextrins, maltodextrins or mixtures thereof. Dextrins, maltodextrins or mixtures thereof may have ED, molecular weights, water solubilities and viscosities described above. Dextrins and maltodextrins are generally degraded starches whose degradation is effected by heating with or without the addition of chemical products, it being possible to recombine degradation fragments under degradation conditions to form new bonds that were not present in this form in the original starch. Roasted dextrins, such as white and yellow dextrins that are prepared by heating wet-dry starch, are usually less preferred, usually in the presence of small amounts of acid. The carbohydrate-derived compound can be prepared as described in Guinther Tegge, Starke und Starkederivate, Behr’s Verlag, Hamburg 1984, p. 173 and p. 220 et seq. And in EP 441 197.

The carbohydrate-derived compound can be prepared from any natural starches, such as cereal starches (eg corn, wheat, rice or barley), tuber and root starches (eg potatoes, tapioca roots or arrowroot ) or sago starches. The carbohydrate-derived compound may also have a bimodal molecular weight distribution and may have a weight average molecular weight as described above. The carbohydrate-derived compound may have an irregularity U (defined as the ratio between the average weight in weight Mw and the average molecular weight in number Mn) that characterizes the molecular weight distribution in the range of 6 to 12, from 7 to 11 or 8 to 10. The weight ratio of carbohydrate-derived compound having a molecular weight of less than 1000 may be 10% to 70% by weight or 20 to 40% by weight. In some embodiments, the carbohydrate-derived compound in an aqueous solution with a concentration of 40% by weight may have a dynamic viscosity r40 [Pa · s], determined according to DIN 53 019 at 25 ° C and a shear gradient of 75 s -1, from 0.01 to 0.06, from 0.015 to 0.04 or from 0.02 to 0.035.

In some embodiments, the carbohydrate-derived compound can be chemically modified such as by etherification or esterification. The chemical modification can also be carried out in advance on a starting starch before its degradation. Esterifications are possible using both inorganic and organic acids, or their anhydrides or chlorides. Also phosphate and acetylated degraded starches can be used. The most common method of etherification is the treatment with organohalogenated compounds, epoxides or sulfates in alkaline aqueous solution. The ethers can be alkyl ethers, hydroxyalkyl ethers, carboxyalkyl ethers and allyl ethers.

The copolymer can be derived from more than 0 to less than about 50% by weight, from about 5 to about 45% by weight, from about 8 to about 40% by weight or from about 15 to about 35% by weight, of the derivative compound of carbohydrate based on the total weight of monomers (or weight of dry polymer on paper).

In addition to the copolymer, the paper coating or agglutination formulation includes a tetrasulfonate-based fluorescent bleaching agent. Suitable tetrasulfonate-based fluorescent bleaching agents include Blankophor® P liquid and Bayer Blankophor® P 150 liquid, which are tetrasulfonated derivatives of 4,4'-diaminoestylbeno-2,2'-disulfonic acid, and Leucophor® T-100 from Clariant Paper Chemicals A portion of the tetrasulfonate based fluorescent bleaching agent may be replaced by a hexasulfonate based fluorescent bleaching agent. On the other hand, although less preferably, up to about 50% of the tetrasulfonate-based fluorescent bleaching agent can be replaced by a disulfonate-based fluorescent bleaching agent. Hexasulfonate-based and disulfonate-based fluorescent bleaching agents are known in the art.

In some embodiments, the fluorescent bleaching agent is not activated. The formulation may be substantially free of an activator used to improve the brightening properties of the fluorescent bleaching agent. Exemplary activators include polyvinyl alcohol, carboxymethyl cellulose, polyvinylpyrrolidone and water insoluble starches. Water insoluble starches are insoluble in water at 25 ° C and are generally not degraded. Water insoluble starches generally have a MW greater than 100,000 (typically 200,000 to 500,000) and an ED of less than 5 (typically about 1). The formulation may be substantially free (eg less than 0.1% by weight based on the solids content of the formulation) of polyvinyl alcohol, carboxymethyl cellulose, polyvinylpyrrolidone and water insoluble starches. The formulation may even be completely free of polyvinyl alcohol (PVOH), carboxymethylcellulose (CMC), polyvinylpyrrolidone (PVP) and water insoluble starches. In some embodiments, an activator may be used but in an amount substantially less than the amount typically used in paper formulations. For example, less than 25% or even less than 10% of the amount of activator typically used, or less than 0.4% by weight or even less than 0.2% by weight based on the total formulation may be included in the formulation . The weight ratio of the activator to the fluorescent bleaching agent is less than 1: 1, less than 0.5: 1, less than 0.2: 1, less than 0.1: 1 or even 0: 1.

The agglutination or paper coating formulation may include fillers, dyes and / or pigments. The fillers can be added to impart certain properties to the paper, such as softness, whiteness, increased density or weight, reduced porosity, increased opacity, smoothness, luster and the like. Suitable charges include calcium carbonate (precipitated or crushed), kaolin, clay, talc, diatomaceous earth, mica, barium sulfate, magnesium carbonate, vermiculite, graphite, carbon black, alumina, silica (pyrolysis or precipitates in powders or dispersions), Colloidal silica, silica gel, titanium oxide, aluminum hydroxide, aluminum trihydrate, satin white, magnesium oxide, plastic pigments, white urea resin pigments and rubber powder.

If the paper is going to be colored or decorated paper, dyes and / or pigments may also be included. Exemplary dyes include basic dyes, acid dyes, direct anionic dyes, cationic direct dyes, anionic pigment dispersions and cationic pigment dispersions. Various organic pigments and inorganic pigments can be used as coloring agents including non-toxic anti-corrosive pigments. Examples of such pigments are anti-corrosive phosphate type pigments such as zinc phosphate, calcium phosphate, aluminum phosphate, titanium phosphate, silicon phosphate and orthophosphates and condensed phosphates thereof; anti-corrosive pigments of molybdate type, such as zinc molybdate, calcium molybdate, calcium and zinc molybdate, potassium and zinc molybdate, potassium and zinc phosphomolibdate and potassium and calcium phosphomolibdate; and anti-corrosive pigments of the borate type such as calcium borate, zinc borate, barium borate, barium metaborate and calcium metaborate.

In some embodiments, the paper agglutination or coating formulation may include a polymer binder that has not been derived from the carbohydrate-derived compound. The polymer binder can be a pure acrylic copolymer, a styrenic-acrylic copolymer, a styrene-butadiene copolymer, a vinyl-acrylic copolymer or one of its mixtures. For example, a styrenic-acrylic copolymer or a styrene-butadiene copolymer could be included.

In some embodiments, the paper agglutination or coating formulation may include a thickener. Suitable thickeners include (meth) acrylic acid / (meth) alkyl acrylate copolymers (eg, Sterocoll® FD thickener and Sterocoll® FS thickener, both commercially available from BASF Corporation), hydroxyethylcellulose, guar gum, Jaguar, carrageenan, xanthan , acetane, konjac mannan, xyloglucan, urethanes and mixtures thereof. The thickener can be added to the formulation as an aqueous dispersion or emulsion or as a solid powder.

In some embodiments, the paper agglutination or coating formulation may include other additives. The additives can be any additive that can generally be included in a coating or paper agglutination composition. Additional additives include surfactants, wetting agents, protective colloids, biocides, dispersing agents, thixotropic agents, stabilizing additives for frozen storage, pH adjusting agents, corrosion inhibitors, ultraviolet light stabilizers, crosslinkers, promoters crosslinking and lubricants.

The paper agglutination or coating composition may include more than 50% solids, 55 to 75% solids or 60 to 70% solids. The copolymer can be present in an amount of 2 to 12% by weight, from 4 to

10% by weight or 6 to 9% by weight of the solids content. The tetrasulfonate fluorescent bleaching agent may be present in an amount of more than 0 to 2% by weight or 0.5 to 1.5% by weight of the solids content. Other polymeric binders may be present in an amount of 0 to 5% by weight, 0 to 3% by weight or 0 to 1% by weight of the solids content. A thickener may be present in an amount of 0 to 5% by weight, more than 0 to 3% by weight or more than 0 to 1% by weight of the solids content. Fillers, pigments and / or dyes may be present in an amount of 82 to 95% by weight or 85 to 90% by weight of the solids content. Other additives may be present in an amount of 0 to 5% by weight, 0 to 3% by weight or 0 to 1% by weight of the solids content.

Aqueous polymer dispersions can be prepared by polymerizing unsaturated monomers using free radical aqueous emulsion polymerization in the presence of the carbohydrate-derived compound. Suitable methods are described in US Pat. UU. No. 6,080,813, which is hereby incorporated by reference in its entirety. The emulsion polymerization temperature is generally 30 to 95 ° C.

or from 75 to 90 ° C. The polymerization medium may include water alone or a mixture of water and water miscible liquids, such as methanol. In some embodiments, water alone is used. The emulsion polymerization can be carried out either as a batch process or in the form of a feeding process, including a stepwise or gradient procedure. In some embodiments, a feed process is used in which part of the polymerization heading is heated to the polymerization temperature and partially polymerized, and the remainder of the polymerization heading is subsequently fed to the polymerization zone continuously, by stages or with the superposition of a concentration gradient, usually through a plurality of spatially separated feed streams, of which one or more contain the monomers in pure or emulsified form, while maintaining the polymerization. The initially introduced mixture and / or the monomer feed stream may contain small amounts of emulsifiers, generally less than 0.5% by weight, based on the total amount of monomers to be polymerized. The monomers can frequently be fed to the polymerization zone after preemulsification with these adjuvant emulsifiers. The feeding process can be designed by initially introducing all of the carbohydrate-derived compound to be used in dissolved form in an aqueous mixture. This means that the aqueous solution produced during the partial hydrolysis of the starting starch can, after the hydrolysis has finished to form the carbohydrate-derived compound, for example by neutralization of the catalytic acid and cooling, also be used directly for emulsion polymerization. watery Prior isolation of the carbohydrate-derived compound, for example by spray drying, is unnecessary but can also be used.

The free radical emulsion polymerization can be carried out in the presence of a free radical polymerization initiator. The free radical polymerization initiators that can be used in the process are all those that are capable of initiating a free radical aqueous emulsion polymerization, including alkali metal peroxydisulphates and H2O2, or azo compounds. Combined systems may also be used comprising at least one organic reducing agent and at least one peroxide and / or hydroperoxide, e.g. eg, tert-butyl hydroperoxide and the metal sodium salt of hydroxymethanesulfinic acid or hydrogen peroxide and ascorbic acid. Combined systems may also be used that additionally contain a small amount of a metal compound that is soluble in the polymerization medium and whose metal component may exist in more than one oxidation state, e.g. e.g., ascorbic acid / iron (II) sulfate / hydrogen peroxide, where ascorbic acid can be replaced by the metal sodium salt of hydroxymethanesulfinic acid, sodium sulphite, sodium hydrogen sulphide or metal sodium bisulfite and hydrogen peroxide can be replaced by tert-butyl hydroperoxide or alkali metal peroxydisulfates and / or ammonium peroxydisulfates. In combined systems, the carbohydrate-derived compound can also be used as the reducing component. In general, the amount of free radical initiator systems employed is 0.1 to 2% by weight, based on the total amount of the monomers to be polymerized. In some embodiments, the initiators are ammonium and / or alkali metal peroxydisulfates (eg sodium peroxydisulfates), alone or as a constituent of the combined systems.

The way in which the free radical initiator system is added to the polymerization reactor during the free radical aqueous emulsion polymerization is not critical. Either everything can be introduced into the polymerization reactor at the beginning or added continuously or in stages as it is consumed during the free radical aqueous emulsion polymerization. In detail, this depends in a manner known to a person skilled in the art both on the chemical nature of the initiator system and on the polymerization temperature. In some embodiments, something is introduced at the beginning and the rest is added to the polymerization zone as it is consumed. It is also possible to carry out the free radical aqueous emulsion polymerization under superatmospheric or reduced pressure.

Aqueous polymer dispersions can be prepared with total solids contents of 10 to 75% by weight, 15 to 65% by weight or 20 to 60% by weight. Next, the aqueous polymer dispersions can be concentrated if desired to provide a total solids content of 40-75% by weight. The aqueous polymer dispersion can be converted, in a manner known per se, into redispersible polymer powders (eg, spray drying, roller drying or drying with suction filter). If the aqueous polymer dispersion is going to

drying, drying aids with the dispersion can be used. The copolymers have a long shelf life and can be redispersed in water for use in the coating or paper agglutination formulation.

The aqueous polymer dispersion can be mixed with the tetrasulfonate-based fluorescent bleaching agent and optionally other components such as polymeric binders, thickeners, fillers, pigments, dyes and other additives. The order of mixing is not critical although sufficient water needs to be present in the formulation for the addition of solid components such as certain fillers.

The coating or agglutination formulation can be applied to the paper as a coating. If the formulation is provided as a coating, it can be applied using any method known in the art such as roller coating, knife coating or a press of measured size. The formulation can be provided in an amount of 7-20 g / m2 per 150 g / m2 of paper. In some embodiments, the formulation may be applied in an amount of less than 15% by weight or 4 to 12% by weight based on the weight of the coated paper.

The resulting paper, such as sheets of paper, cardboard and cardboard, comprises a fibrous matrix and a binder composition comprising a copolymer obtained by polymerization of an unsaturated monomer and a carbohydrate-derived compound and a tetrasulfonate-based fluorescent bleaching agent. The binder can be provided as a coating layer on a paper substrate. The paper substrate that is coated with the formulation can be any paper substrate including, but not limited to, paper, cardboard and cardboard. The formulation can be used with any type of paper coating process such as rotogravure, sheet offset, coil offset and flexographic procedure.

In this application, the weight average molecular weight data for the carbohydrate-derived compound, unless expressly stated otherwise, is determined using gel penetration chromatography (GPC), carried out under the following conditions:

Columns: 3 steel units measuring 7.5 X 600 mm, filled with TSK G 2000 PW gel; G 3000 PW and G 4000 PW. 5 µm mesh

Eluent: Distilled water.

Temp .: TA (room temperature)

Detection: Differential refractometer (for example ERC 7511)

Flow rate: 0.8 ml / min, pump (for example ERC 64.00)

Injection volume: 20 µl, valve (for example VICI 6-way valve)

Evaluation: Bruker Chromstar GPC program

Calibration: Calibration was carried out in the low molecular weight range using glucose, raffinose, maltose and maltopentose. For the higher molecular weight range, a pululane pattern having a polydispersity <1.2 was used.

As described herein, the Prufbau offset test was performed as follows:

one.

 Definitions

1.1. Impressions - passes through the machine.

1.2. Repelling - the lifting of any portion of a paper or coating surface during typographic printing due sometimes to improper sizing and sometimes because the ink is excessively sticky.

2.

 Process

2.1. Device / Reagent Requirements

2.1.1. Multivalent typographic testing machine (Dr. Druner System - Prufbau)

2.1.2. Ink - Novagloss 4 G 655 - K + ink for EA standard offset tests

2.1.3. Print Form - 4 cm wide aluminum disc

2.1.4. Printing Pressure - 800 N

2.1.5. Print Speed - 1 m / s constant

2.1.6. Inking Unit Requirements - 0.3 ml of ink per sample, distribution time

-

 30 seconds, inking time of the print form - 30 seconds

2.1.6.1. Only one disc from each inking station should be used, which is subsequently cleaned, so that fresh ink is used for each sample.

2.1.6.2. If more than four tests are to be performed, the rubber roller must be cleaned.

2.2. Stages of the Procedure

2.2.1. Prepare the sample (paper or cardboard) allowing it to condition for 24 hours under standard TAPPI conditions. Conditioning should be maintained throughout the test.

2.2.2. Cut the samples to measure approximately 240 mm ± 2 mm by 47 ± 0.5 mm. If the sample is too wide, it may interfere with the march through the device. If the sample is too narrow, it may result in the sample being left laterally, or biased.

2.2.3. Place the sample under the clamp located at the end of the sample carrier and fold the sample 180 ° so that it rests flat and parallel on the carrier with the face to be tested facing up. Secure the free end with tape. Do not allow fingerprints to contaminate the portion of the sample to be tested.

2.2.4. The mounted sample is placed in the lane before the printing station and the printing disc is installed. The carrier must have the clamp on the back, so that the tape end of the samples is printed first.

2.2.5. Print the sample.

2.2.6. With the same print disc, after a 10 second pause, print again. Note: the length of the pause can be adjusted to achieve a desired repel. Do not clean the disc between prints.

2.2.7. After another pause of the same duration, print the sample again. The sample is printed a certain number of times or until it begins to repel, in which case the number of prints is noted.

2.2.8 The number of prints that are made when the replay occurs is noted. If repellent does not occur during the last print, the symbol> and the number of the last print are noted. Note: Through progressive drying on both the paper and the printing disc, the ink becomes more sticky. The paper is then subjected to an increasing force from print to print. The tighter the coating is against the fluid portion of the ink, (the lower the increase in the viscosity of the ink), the more passes are possible before the re-starting begins.

As described herein, the Prufbau wet repel test was performed as follows:

1. Procedure

1.1. Device / Reagent Requirements

1.1.1. Multipurpose typographic testing machine (Prufbau with attached wetting unit)

1.1.2. Ink - Test Ink

1.1.3. Print Form - 4 cm wide blanket disk

1.1.4. Printing Pressure - 600 N

1.1.5. Print Speed - 3 m / s constant

1.1.6. Moisture Unit Speed - 1 m / s constant

5 1.1.7. Inking Unit Requirements - approximately 0.16 ml

1.1.8. Wetting Solution - 10 µl of a 90/10 combination of water and isopropyl alcohol (The amount of solution can be increased until repelling is achieved.)

1.1.9. Delay Timer of the Moistening Unit set to reach the

repelled (Start in 1 second, then adjust the delay on the control sample as necessary to observe the repellant.

1.2. Stages of the Procedure

1.2.1. Prepare the sample (paper or cardboard) allowing it to condition for 24 hours under standard TAPPI conditions. Conditioning should be maintained throughout the test. Cut the horn samples measuring approximately 240 mm ± 2 mm by 47

15 ± 0.5 mm If the sample is too wide, it may interfere with the march through the device. If the sample is too narrow, it may result in the sample being left laterally, or biased.

1.2.2. Place the sample under the clamp located at the end of the sample carrier and fold the sample 180 ° so that it rests flat and parallel on the carrier with the

20 face to be tested up. Secure the free end with tape. Do not allow fingerprints to contaminate the portion of the sample to be tested.

1.2.3. Start the power and the cooling unit. Place the ink distribution roller in contact with the conductive rollers. Start the distributor rollers and let them run for at least 15 minutes before testing to allow

25 temperature control balance.

1.2.4. Place the carrier, with the sample attached, in the slot of the carrier in front of the moistening unit.

1.2.5. Fill the pipette of the wetting unit to 10 µl with a wetting solution and place it in the wetting unit.

30 1.2.6. Stop the ink distribution rollers and apply approximately 0.16 ml (1.6 turns in the ink pipette) of ink to the roller station.

1.2.7. Start the ink distribution rollers and the timer simultaneously.

1.2.8. After 30 seconds of elapsed time, contact the felt printing disc with the ink roller.

35 1.2.9. Release the wetting solution at the same time on each sample in the series (range of 50 to 54 seconds).

Start the wetting rollers to release the solution.

1.2.10. After 60 seconds of elapsed time, remove the printing disc from the ink roller and mount on the core of the printing unit.

40 Start the core motor.

1.2.11. At the time of the wetting alarm, lift the lever over the jet. This will send the carrier through the wetting and printing stations.

1.2.12. Remove the test strip from the carrier and allow the ink to dry before detecting the density of the ink.

1.2.13. Stop the core drive motor and the wetting unit.

1.2.14. Repeat steps 1.2.4 to 1.2.13 for each sample to be tested.

5 1.2.15. With the help of a densitometer, determine the density of the ink in 10 dry areas and 10 wet areas of each strip. Introduce the average density in the dry area. Introduce the average density in the wet area. Present the% ink retention ((Medium in Wet / Medium in Dry) X 100)).

Examples

10 A standard coated paper pulp free sheet coating color was formulated using 70 parts Hydrocarb® 90 crushed calcium carbonate and 30 parts Hydralux® 91 fine kaolin clay. The level of binders in the coating formulation was set at 12 parts The binders evaluated were Styronal® BN 4606 latex binder as a commercial control. The carboxylated styrene-butadiene emulsion polymers containing 58% styrene, 38% butadiene and 4% acrylic acid were used as laboratory controls

15 (Comparative Examples 1 and 2). Two separate polymerized laboratory binders (Examples 1 and 2) were prepared in the same manner as in Comparative Examples 1 and 2, except that the binder copolymers were derived using 30 parts of a maltodextrin compound per 100 parts of monomer (i.e., styrene, butadiene and acrylic acid). The maltodextrin compound had an ED = 18 and an Mw of 11,000. Blancophor® P, a 4,4’-diamino-stilbene-2,2’-disulfonic acid tetrasulfonated derivative, was used as a bleaching agent

20 fluorescent in all formulations. Standard fully synthetic formulations using Sterocoll® FD as a thickener were also compared with formulations using standard activators for the fluorescent bleaching agent, including polyvinyl alcohol (PVOH) (Elvano® 51-03L24); carboxymethyl cellulose (CMC) (Finnfix® 10) and a water insoluble starch (Penford® Gum 280). In formulations in which activators were used, the level of Sterocoll® FD was reduced by viscosity considerations; however, the settings of the

The level of binder was only performed under the conditions in which two parts by weight of starch were used as the activator. Calsan® 50, a calcium stearate from BASF Corporation, was used as a lubricant. Eleven coating formulations were prepared as shown in Table 1.

TABLE 1 5

Formulation

one 2 3 4 5 6 7 8 9 10 eleven

Hydrocarb 90

70 70 70 70 70 70 70 70 70 70 70

Alphalux 91

30 30 30 30 30 30 30 30 30 30 30

Stryonal BN 4606

12

Comparative Example 1

 12 12 eleven 12

Comparative Example 2

12

Example 1

12 12 eleven 12

Example 2

  12

(continuation)

Formulation

one 2 3 4 5 6 7 8 9 10 eleven

Blancophor P

one one one one one one one one one one one

Sterocoll FD

0.3 0.3 0.3 0.3 0.3 0.2 0.2 0.2 0.2

Penford 280

2 2

PVOH

    0.5 0.5

Finnfix 10

       0.8 0.8

Calsan 50

one one one one one one one one one one one

Solids

68.5 68.5 68.5 68.5 68.5 68.5 68.5 67.5 67.5 67.7 67.7

Visc. Brookfield at 100 RPM

2624  3068 3256  3040  3100  1980  1920  3324  3272  2508  2260

Hercules High Shear Viscosity

61.0 63.5 71.4 66.3 74.5 46.2 58.5 68.0 68.6 41.3 42.2

The coating formulations were applied on base material for standard mechanical pulp free sheets using a Modem Metal Kraft table topper. The base sheet did not include fluorescent bleaching agents. The objective of the coating weight was 12.5 g. All papers were calendered using a supercalandria with a contact line and 89.3 kg per linear cm (500 pounds per linear inch).

The papers were tested for CIE and TAPPI brightness as shown in Figures 1-3. The CIE brightness was tested with and without the filtered ultraviolet light. The "difference" between the brightness with included UV light and filtered (or excluded) UV light was considered an indication of the various carriers that activated the fluorescent bleaching agent and is shown in Figure 2. The TAPPI T452 Test was used to determine TAPPI brightness.

As can be seen from Figures 1-3, the binder containing maltodextrin of Examples 1 and 2 improves the gloss of the coating. This is particularly evident when comparing the Styronal® BN 4606 latex formulation and Comparative Examples 1 and 2 directly with Examples 1 and 2. Enhanced optical brightener activation of the maltodextrin-derived binder copolymer was evident even in formulations that did not contain activators .

The repel test was also performed on the test papers. In particular, the Prufbau offset test, the IGT dry repel test and the Prufbau wet repel test were all performed on the paper that included the test formulations. Figure 4 is a graph showing the Prufbau Ósset for paper using the compositions tested and this test was performed as described above. Figure 5 is a graph showing the IGT Dry Repellent in feet / min for paper using the compositions tested and these tests were carried out using TAPPI 499. Figure 6 is a graph showing Prufbau's wet repellent of paper using the compositions tested and this test was also performed as described above.

As can be seen in Figure 4, the binder copolymers derived from maltodextrin (Examples 1 and 2) had improved offset test results. This improvement was clearly seen in formulations in which no activators were used. In formulations using an activator such as a water insoluble starch, PVOH or CMC, no appreciable differences were observed in the passes until failure.

The IGT dry repel results are given in Figure 5. The average IGT of the Styronal® BN 4606 latex sample, Comparative Example 1 and Comparative Example 2 where no activator was used was 183 ft / min while the IGT Medium of Examples 1 and 2 (using the binder copolymers derived from maltodextrin) without activators was 207 feet / min. However, when PVOH or CMC was used as the activator, Styronal® BN 4606 and Comparative Examples 1 and 2 indicated a slightly higher resistance but

comparable compared to the binder copolymer derived from maltodextrin (Examples 1 and 2).

Prufbau wet repel tests are provided in Figure 6. These results show that the maltodextrin-derived binder copolymer provided lower wet repellent resistance against the Styronal® BN 4606 example and Comparative Examples 1 and 2. Without However, it should be noted that the examples did not include crosslinking agents and these are typically included in totally synthetic wood-free grades, which would have increased the wet repel resistance of the binder copolymers derived from maltodextrin. For example, a glyoxal type crosslinker could be included in formulations based on Examples 1 and 2 for use in formulations for sheet offset.

A formulation (Comparative Example 3) was prepared which included 60 parts by weight of calcium carbonate (HC 90 Omya), 40 parts by weight of clay (Hydragloss 90 Huber), 14 parts by weight of Acronal® S728 styrenic acrylic latex as a binder (available from BASF Corporation), 0.2 parts by weight of dispersant (Colloids 226), 0.8 parts by weight of calcium stearate lubricant (Calsan® 50), 0.3 parts by weight of Sterocoll® FS thickener, 2.3 parts by weight of tetrasulfonated fluorescent bleaching agent (Leucophor® T-100 from Clariant Paper Chemicals) and 3.3 parts by weight of polyvinyl alcohol as an activator. The resulting formulation for Comparative Example 3 had 65% solids and was adjusted to a pH of 8.5 using caustic soda.

In Examples 3 and 4, the formulation of Comparative Example 3 was modified by modifying the Acronal® S728 latex to include 24 parts by weight of maltodextrin (per 100 parts by weight of monomer). In addition, the amount of polyvinyl alcohol activator was 0.5 parts by weight in Example 3 and 1.0 parts by weight in Example 4, respectively.

Figure 7 is a graph showing the TAPPI gloss of cardboard using Comparative Example 3, Example 3 and Example 4. As shown in this figure, the brightness values for Examples 3 and 4 with significantly less activator were comparable to the brightness value for Comparative Example 3.

Comparative Example 4 was prepared using the same formulation as Comparative Example 3 but including styronal butadiene latex Styronal® BN 4606X as the binder. Example 5 was prepared as Comparative Example 4 except that Styronal® BN 4606X styrene-butadiene latex was modified to include 22 parts by weight of maltodextrin (per 100 parts of monomer). In addition, Example 5 did not include polyvinyl alcohol activator.

Figure 8 is a graph showing the CIE brightness with UV included minus the CIE brightness with UV excluded from Example 5 and Comparative Example 4 when applied to glass with paper backs. As shown in this figure, the presence of maltodextrin in Example 5 significantly improves the CIE brightness difference of the composition, even if no activator is included.

A number of embodiments of the invention have been described. However, it should be understood that various modifications can be made without departing from the spirit and scope of the invention. In addition, although only certain representative combinations of the formulations, methods or products disclosed herein are specifically described, other combinations of the steps of the method or combinations of elements of a composition or product are intended to fall within the scope of the attached claims. Thus, a combination of stages, elements or components may be explicitly mentioned herein; however, all other combinations of stages, elements and components are included, even if not explicitly indicated.

Claims (26)

1. A paper coating or agglutination formulation, comprising: an aqueous polymer dispersion comprising a copolymer obtained by the polymerization of an unsaturated monomer and a carbohydrate-derived compound having a dextrose equivalent (DE) of 10 to 35; Y a fluorescent bleaching agent based on tetrasulfonate.

2.

 The formulation according to claim 1, wherein the carbohydrate-derived compound is selected from the group consisting of dextrins, maltodextrins and mixtures thereof.

3.

 The formulation according to claim 1 or 2, wherein the DE of the carbohydrate-derived compound is 12.5 to 25, preferably 15 to 20.

Four.

 The formulation according to any of claims 1-3, wherein the molecular weight of the carbohydrate-derived compound is 3000 to 20,000, preferably 5000 to 17000.

5.

 The formulation according to any of claims 1-4, wherein the carbohydrate-derived compound is soluble in water at room temperature in an amount of more than 40% by weight.

6.

The formulation according to any of claims 1-5, wherein the copolymer is selected from the group consisting of pure acrylic copolymers, styrenic-acrylic copolymers, styrene-butadiene copolymers and vinyl-acrylic copolymers.

7.

The formulation according to any of claims 1-6, wherein the copolymer is selected from the group consisting of styrenic-acrylic copolymers.

8.

 The formulation according to any of claims 1-7, wherein the unsaturated monomer includes a monomer selected from the group consisting of styrene, (meth) acrylic acid, esters of (meth) acrylic acid, (meth) acrylamide, (meth) acrylonitrile and mixtures

9.

 The formulation according to any of claims 1-8, wherein the copolymer is derived from 5 to 45, preferably from 8 to 40 percent by weight of the carbohydrate derived compound based on the total weight of monomers.

10.

 The formulation according to any of claims 1-9, wherein the aqueous polymer dispersion comprises a dispersed phase and an aqueous phase and the carbohydrate-derived compound provided in the copolymer is present in the dispersed phase.

eleven.

 The formulation according to any of claims 1-10, wherein said fluorescent bleaching agent is not activated.

12.

 The formulation according to any of claims 1-11, wherein the formulation is free of polyvinyl alcohol, carboxymethyl cellulose, polyvinylpyrrolidone and water insoluble starches.

13.

 The formulation according to any one of claims 1-12, wherein the aqueous polymer dispersion further comprises a fluorescent bleaching agent based on hexasulfonate.

14.

 A method for preparing a paper coating or agglutination formulation, comprising:

polymerizing a mixture of an unsaturated monomer and a carbohydrate-derived compound having a dextrose equivalent (DE) of 10 to 35, in an aqueous medium to produce a copolymer in an aqueous polymer dispersion; Y mixing the aqueous polymer dispersion with a tetrasulfonate-based fluorescent bleaching agent. 15. A method to improve the bleaching properties of paper; which includes: providing an aqueous polymer dispersion comprising a copolymer obtained by polymerization of an unsaturated monomer and a carbohydrate derived compound having a dextrose equivalent (SD) from 10 to 35; mixing the aqueous polymer dispersion with tetrasulfonate-based fluorescent bleaching agent to produce a paper coating or agglutination formulation; Y Apply the formulation as a paper coating.

16.

 The method according to claim 15, wherein said provision step comprises polymerizing a mixture of an unsaturated monomer and a carbohydrate-derived compound having a dextrose equivalent (DE) of 10 to 35, in an aqueous medium to produce the copolymer. .

17.

 The method according to any of claims 14-16, wherein the carbohydrate-derived compound is a compound as defined in claims 2-4.

18.

 The method according to any of claims 14 and 16-17, wherein said polymerization step comprises first mixing at room temperature an aqueous solution of a carbohydrate-derived compound comprising more than 40% by weight of the carbohydrate-derived compound with the unsaturated monomer and polymerize the mixture to form the copolymer.

19.

 The method according to claim 14-18, wherein the copolymer is derived from 5 to 45 percent by weight of the carbohydrate derived compound based on the total weight of monomers.

twenty.

 The method according to claim 14-19, wherein said fluorescent bleaching agent is not activated.

twenty-one.

 The method according to claim 14-20, wherein the formulation is free of polyvinyl alcohol, carboxymethyl cellulose, polyvinylpyrrolidone and water insoluble starches.

22

 Paper comprising a fibrous matrix and a binder composition comprising a copolymer obtained by polymerization of an unsaturated monomer and a carbohydrate derived compound as defined in claims 1-5 having a dextrose equivalent (DE) of 10 to 35 and a tetrasulfonate based fluorescent bleaching agent.

2. 3.

 Paper according to claim 22, wherein the copolymer is derived from 5 to 45 percent by weight of the carbohydrate derived compound based on the dry polymer weight.

24.

 Paper according to any of claims 22-23, wherein the fluorescent bleaching agent is not activated.

25.

 Paper according to any of claims 22-24, wherein the binder is free of polyvinyl alcohol, carboxymethyl cellulose, polyvinyl pyrrolidone and water insoluble starches.

26.

 Paper according to any of claims 22-25, wherein the binder is provided as a coating layer on a paper substrate.