EP0043790B1 - Process for increasing or improving the whitening effect during the optical brightening of coating compositions - Google Patents

Abstract

A process is disclosed for obtaining coating compositions of improved whiteness for coating paper or cardboard using fluorescent whitening agents of the bis-triazinylaminostilbene-2,2'-disulfonic acid series, which process comprises adding to the coating compositions, in addition to the respective fluorescent whitening agent, an acid phosphoric acid ester of an oxyalkylated fatty amine of the formula <IMAGE> (1) or an alkali metal salt, ammonium salt or amine salt thereof, wherein R is an aliphatic hydrocarbon radical of 8 to 22 carbon atoms, Y1 and Y2 are both hydrogen, or one of Y1 and Y2 is hydrogen and the other is methyl, X is the acid radical of phosphoric acid, the acid hydrogen atoms of which radical can be replaced by alkali metal ions, ammonium ions or amine salt ions, and m and n are integers, the sum of which is 2 to 30. To the coating compositions can also be added organic solubilizers, non-ionic or anionic surfactants and/or polar organic compounds. Coating compositions which contain the above fluorescent whitening agents and assistants are also disclosed.

Description

The present invention relates to a method for increasing or improving the white effect in the optical brightening of coating slips for the coating of paper or cardboard with the aid of brighteners of the bis-triazinylaminostilbene-2,2'-disulfonic acid series and optically brightened coating slips and paper coated with these coating slips or box.

Brighteners from the class of bis-triazinylaminostilbene-2,2'-disulfonic acids are also suitable for lightening paper. When lightening coating slips, however, problems occur depending on the brightener and the composition of the coating slip, so that either insufficient white effects are obtained or that some brighteners are out of the question for application in certain coating slips. Particularly at higher brightener concentrations, there is often a sharp decrease in the degree of whiteness instead of an increase in the degree of whiteness, with the coating composition often becoming greener. This undesirable effect occurs in some of the brighteners mentioned, particularly in the case of coating slips with artificial binders.

Efforts have already been made to deal with the difficulties described. Solubilizers, especially polyethylene glycol, were added to the coating slip. With some brighteners, this measure brings a certain increase in effect, with other brighteners, in turn, it fails. In addition, if effect increases are achieved, these are often insufficient.

Furthermore, the addition of surfactants (see GB-A-1 294 173) or of amide-formaldehyde resins (see DE-A-2 229 872) has been proposed in the lightening of the coating slips. Brightenings are then obtained, but they do not meet the requirements regarding whiteness. Otherwise, these measures can only be applied in coating slips with synthetic binders, but not for the technically important mixtures of natural and synthetic binders.

DE-A-2 806 194 and 2 806 195 disclose coating compositions to which a dispersion brightener, but also bis-triazinylaminostilbene-2,2'-disulfonic acid brightener, mixed with water, an organic liquid boiling above 150 ° C., e.g. B. triethyl phosphate, trioctyl phosphate, tricresyl phosphate or trichloroethyl phosphate, and a solubilizer, for. B. a nonionic emulsifier is added. This method is mainly suitable for dispersion brighteners. In addition, the use of relatively expensive, high-boiling organic solvents is not advantageous for various reasons.

DE-A-2 412 785 describes a process for optically brightening cellulose and polyamide textiles in which certain oxyalkylation products of fatty amines, optionally esterified with sulfuric acid, are used as auxiliaries. By using these aids, the maximum white that can be achieved on textiles can be increased slightly. An application in the paper sector is not mentioned.

It was an object of the present invention to find a process which does not have the disadvantages described in the lightening of coating slips, which leads to higher whitening effects, especially when bistriazinylaminostilbene-2,2'-disulfonic acid lightening agents are used in coating slips, which leads to higher whitening effects Lightening concentrations of greening that frequently occurs are eliminated and this should enable the use of some brighteners of the class mentioned in coating slips which were previously not considered suitable for this application.

Surprisingly, this object was achieved by adding an acidic phosphoric acid ester of a fatty amine oxalkylation product of the formula (1) below to the coating slip in addition to the brightener. This measure significantly improves the whiteness of the lightened coating slips, in particular at higher brightener concentrations, and the undesired greening is avoided. In contrast to the usual lightening of coating slips with bis-triazinylaminostilbene-2,2 'disulfonic acid brighteners, the degree of whiteness increases practically linearly with the logarithm of the increasing brightener concentration, so that very high degrees of whiteness can be achieved.

oder dessen Alkalimetall-, Ammonium- oder Aminsalz einverleibt, worin R einen aliphatischen Kohlenwasserstoffrest mit 8-22 C-Atomen, Y₁ und Y₂ beide Wasserstoff oder eines dieser beiden Symbole Wasserstoff und das andere Methyl, X den Säurerest der Phosphorsäure, wobei die sauren Wasserstoffatome dieses Restes durch Alkalimetall-, Ammonium- oder Aminsalzionen ersetzt sein können, und m und n ganze Zahlen bedeuten, wobei die Summe n + m zwischen 2 und 30 liegt.The process for increasing or improving the white effect in the optical brightening of coating slips for the coating of paper or cardboard with the aid of brighteners of the bis-triazinylamino-2,2'-disutonic acid series is now characterized in that the coating slips are in addition to the respective Brightener an acidic phosphoric acid ester of a fatty amine oxyalkylation product of FormAl

or incorporates its alkali metal, ammonium or amine salt, in which R is an aliphatic hydrocarbon radical having 8-22 carbon atoms, Y ₁ and Y _{2 are} both hydrogen or one of these two symbols is hydrogen and the other methyl, X is the acid radical of phosphoric acid, the acidic hydrogen atoms of this radical can be replaced by alkali metal, ammonium or amine salt ions, and m and n are integers, the sum n + m being between 2 and 30.

worin R' einen Alkyl- oder Alkenylrest mit 10 bis 18 C-Atomen, X' den Säurerest der Phosphorsäure, wobei die sauren Wasserstoffatome dieses Restes auch durch Alkalimetall- oder Ammoniumionen ersetzt sein können, und n' und m' ganze Zahlen bedeuten, wobei die Summe n' + m' zwischen 4 und 20 liegt.In auxiliaries of the formula (1) used in the process according to the invention, the aliphatic radical R preferably denotes an alkyl or alkenyl radical (branched or unbranched) having 10 to 18 carbon atoms. Auxiliaries which can preferably be used correspond to the formula

wherein R 'is an alkyl or alkenyl radical having 10 to 18 carbon atoms, X' is the acid radical of phosphoric acid, the acidic hydrogen atoms of this radical can also be replaced by alkali metal or ammonium ions, and n 'and m' are integers, where the sum n '+ m' is between 4 and 20.

Compounds of the formula (2) in which n '+ m' is 6 to 8 are particularly preferably used, in particular those in which R 'represents the lauryl radical (C ₁₂ H ₂₅ ). The number 8 is then particularly advantageous for the sum n '+ m'.

In general, the radical R need not have a certain number of carbon atoms, but can also be a mixture of hydrocarbon chains of different lengths, as is the case with many fatty amines derived from natural fats. A preferred residue of this type is the hydrocarbon residue of tallow fatty amine. In formula (1), V _I and Y _{2 are} preferably hydrogen.

The acid component of the ester of formula (1) is phosphoric acid. X is therefore the rest of the phosphoric acid, and the terminal OH groups of the ethylene oxide or propylene oxide chains can be completely or only partially esterified. The number of acidic hydrogen atoms in the phosphoric acid residue X depends on the degree of esterification, which need not be an integer. These acidic hydrogen atoms can also be replaced by alkali metal, ammonium or amine salt ions, so that the residue X is in salt form. However, the radical X is preferably in its acidic form.

Depending on the degree of esterification, possible boundary structures of the compounds of the formula (1) would be, for example, the following (for Y, = Y ₂ = H):

usw.

etc.

eingesetzt, worin

• M Wasserstoff, ein Alkalimetall-, Ammonium - oder Aminsalzion,
• R¹ und R²
  
  
  
  
  
  
  oder
  
  bedeuten.

Bis-triazinylaminostilbene-2,2'-disulfonic acid brighteners which are used according to the invention for the optical brightening of coating slips are, in particular, those of the formula

used where

• M is hydrogen, an alkali metal, ammonium or amine salt ion,
• R ¹ and R ²
  
  
  
  
  
  
  or
  
  mean.

worin R;

A brightener of the formula is preferably used

wherein R;

R₂

oder

und M' Wasserstoff oder ein Alkalimetallion, ein Ammonium-, Diäthanolammonium- oder Triäthanolammonium bedeuten.or

R ₂

or

and M 'represents hydrogen or an alkali metal ion, ammonium, diethanolammonium or triethanolammonium.

The sulfo groups -S0 ₃ M in the compounds of formula (3) can be in free form (M = H) or in salt form. M then denotes an alkali metal ion, in particular a sodium, potassium ion, an ammonium ion or an, amine salt ion, e.g. B. a primary or secondary alkylamine, the alkyl group (s) by halogen. Hydroxy (e.g. ethanolamine, diethanolamine, triethanolamine) or alkoxy may be substituted or a cyclic amine e.g. B. a piperidine, pyrrolidine, piperazine or morpholine.

The acidic hydrogen atoms in the phosphoric acid residue X of the compounds of formula (1) or (2) can optionally be replaced by the same ions as defined for M above. The rest X is then in salt form.

In addition to the brighteners and auxiliaries of the formula (1), it may often be expedient to incorporate further substances into the coating slips which either further improve the effect or which have a positive effect on the properties of the coating slurry in another way. Non-ionic or anionic surfactants, organic solubilizers and / or certain organic polar compounds can be considered as such additional aids.

• Niedere einwertige Alkohole, mehrwertige Alkohole, Ätheralkohole, nicht zu hochmolekulare Polyglykole oder Carbonsäureamide. Beispiele solcher Lösungsmittel sind Propanol, Isopropanol, Äthylenglykol, Propylenglykol, Butylenglykol, Glycerin, Äthylenglykolmonomethyl-, monoäthyl-, -monopropyl- oder -monobutyläther, Dipropylenglykol, Formamid, Dimethylformamid, Dimethylacetamid und N-Methylpyrrolidon. Bevorzugt sind hierbei Äthylenglykol und Polyäthylenglykole. Weiters kommen Amine wie Triäthanolamin und andere wasserlösliche polare Verbindungen wie Dimethylsulfoxid, Dimethylmethanphosphonat, Dimethylsulfon, Sulfolan (=Tetrahydrothiophen-1,1-dioxid), Äthylen-oder Propylencarbonat sowie Harnstoff oder substituierte Harnstoffe, beispielsweise Tetramethylharnstoff, in Betracht.

The following can be used as organic solubilizers and polar organic compounds:

• Lower monohydric alcohols, polyhydric alcohols, ether alcohols, not too high molecular weight polyglycols or carboxamides. Examples of such solvents are propanol, isopropanol, ethylene glycol, propylene glycol, butylene glycol, glycerin, ethylene glycol monomethyl, monoethyl, monopropyl or monobutyl ether, dipropylene glycol, formamide, dimethylformamide, dimethylacetamide and N-methylpyrrolidone. Ethylene glycol and polyethylene glycols are preferred. Amines such as triethanolamine and other water-soluble polar compounds such as dimethyl sulfoxide, dimethyl methane phosphonate, dimethyl sulfone, sulfolane (= tetrahydrothiophene-1,1-dioxide), ethylene or propylene carbonate and urea or substituted ureas, for example tetramethyl urea, are also suitable.

• Anlagerungsprodukte von Alkylenoxiden, insbesondere von Äthylenoxid, an höhere Fettsäuren, Fettsäureamide, aliphatische Alkohole, Mercaptane oder Amine, an Alkylphenole oder Alkylthiophenole, deren Alkylreste mindestens 7 Kohlenstoffatome aufweisen oder an Phenylphenole wie z. B. Polyglykol-(monoalkyl-phenyl)-äther, deren Alkylgruppe 8 bis 12 Kohlenstoffatome aufweist, mit mindestens 8 gegebenenfalls substituierten Glykoleinheiten, wie Decaäthylenglykol-mono-octoyl-phenyläther oder das Umsetzungsprodukt von Monononylphenol mit 5 bis 35 Molen Äthylenoxid; Blockpolymere aus Äthylenoxid und höheren Alkylenoxiden, wie z. B. Propylenoxid oder Butylenoxid; nichtionogene Ester der Anlagerungsprodukte von Alkylenoxiden, wie z. B. der tertiäre Phosphorsäureester des Anlagerungsproduktes von 40 Molen Äthylenoxid an Monononylphenol; Ester von Polyalkoholen, insbesondere Monoglyceride von Fettsäuren mit 12 bis 18 Kohlenstoffatomen, z. B. die Monoglyceride der Laurin-, Stearin- oder Ölsäure; N-acylierte Alkanolamine des gleichen Typs wie bei den Sulfaten dieser Verbindungen erwähnt (siehe unten), so z. B. die N,N-Bis-(ω-hydroxyalkyl)-amide der unter dem Sammelbegriff »Cocosölfettsäuren« zusammengefaßten Säuregemische, vor allem N,N-Bis-(β-hydroxyäthyl)- oder N,N-Bis-(y-hydroxypropyl)-amide, ferner die Anlagerungsprodukte von Äthylenoxid an diese N-acylierten Alkanolamine; Reaktionsprodukte von höheren Fettsäuren mit einem Alkanolamin, wobei das Molverhältnis Alkanolamin zu Fettsäure größer als 1, z. B. 2, ist. Als Fettsäuren kommen vor allem solche mit 8 bis 18 Kohlenstoffatomen sowie die als Cocosölfettsäuren bezeichne-ten Gemische, als Alkanolamine insbesondere Diäthanolamin, in Betracht.

Examples of nonionic surfactants that can be used are:

• Addition products of alkylene oxides, especially of ethylene oxide, to higher fatty acids, fatty acid amides, aliphatic alcohols, mercaptans or amines, to alkylphenols or alkylthiophenols, the alkyl radicals of which have at least 7 carbon atoms or to phenylphenols such as, for. B. polyglycol (monoalkylphenyl) ether, the alkyl group of which has 8 to 12 carbon atoms, with at least 8 optionally substituted glycol units, such as decaethylene glycol mono-octoyl phenyl ether or the reaction product of monononylphenol with 5 to 35 moles of ethylene oxide; Block polymers of ethylene oxide and higher alkylene oxides, such as. B. propylene oxide or butylene oxide; nonionic esters of the adducts of alkylene oxides, such as. B. the tertiary phosphoric acid ester of the adduct of 40 moles of ethylene oxide with monononylphenol; Esters of polyalcohols, especially monoglycerides of fatty acids with 12 to 18 carbon atoms, e.g. B. the monoglycerides of lauric, stearic or oleic acid; N-acylated alkanolamines of the same type as mentioned for the sulfates of these compounds (see below), e.g. B. the N, N-bis (ω-hydroxyalkyl) amides of the acid mixtures summarized under the collective term "coconut oil fatty acids", especially N, N-bis (β-hydroxyethyl) - or N, N-bis- (y- hydroxypropyl) -amides, also the addition products of ethylene oxide with these N-acylated alkanolamines; Reaction products of higher fatty acids with an alkanolamine, the molar ratio of alkanolamine to fatty acid being greater than 1, e.g. B. 2. Suitable fatty acids are, in particular, those having 8 to 18 carbon atoms and the mixtures referred to as coconut oil fatty acids, and, in particular, diethanolamine as alkanolamines.

• Sulfatierte Alkylenoxidaddukte, insbesondere sulfatierte Äthylenoxidaddukte, wie sulfatierte Anlagerungsprodukte von 1 bis 40 Mol Äthylenoxid an Fettsäureamide, Mercaptane oder Amine, besonders aber an Fettsäuren, aliphatische Alkohole oder Alkylphenole mit 8 bis 20 Kohlenstoffatomen in der Alkylkette, z. B. an Stearinsäure, Ölsäure, Laurylalkohol, Myristylalkohol, Stearylalkohol, Oleylalkohol, Octylphenol oder Nonylphenol. Anstelle der Sulfate können auch die Ester anderer mehrwertiger Säuren eingesetzt werden. Hierher gehören z. B. die primären und sekundären Ester der Phosphorsäure sowie die Halbester der Sulfobernsteinsäure; Sulfate N-acylierter Alkanolamine, z. B. die sulfatierten Amide von Capryl-, Pelargon-, Caprin-, Laurin-, Myristin- oder Stearinsäure oder von durch Alkylphenoxygruppen substituierten niederen Fettsäuren, wie Octyl- oder Nonylphenoxyessigsäure, mit Mono- oder Bis-hydroxyalkylaminen, wie β-Hydroxyäthylamin, γ-Hydroxypropylamin, β,γ-Dih- ydroxypropylamin, Bis-(β-hydroxyäthyl)-amin oder mit N-Alkyl-N-hydroxyalkylaminen, wie N-Methyl- bzw. N-Äthyl-N-(β-hydroxyäthyl)-amin; Sulfatierte veresterte Polyoxyverbindungen, z. B. sulfatierte partiell veresterte mehrwertige Alkohole, wie das Natriumsalz des sulfatierten Monoglycerids der Palmitinsäure.

The following can be used as anionic surfactants:

• Sulfated alkylene oxide adducts, in particular sulfated ethylene oxide adducts, such as sulfated addition products of 1 to 40 moles of ethylene oxide with fatty acid amides, mercaptans or amines, but especially with fatty acids, aliphatic alcohols or alkylphenols with 8 to 20 carbon atoms in the alkyl chain, e.g. B. on stearic acid, oleic acid, lauryl alcohol, myristyl alcohol, stearyl alcohol, oleyl alcohol, octylphenol or nonylphenol. Instead of the sulfates, the esters of other polyvalent acids can also be used. This subheading includes: B. the primary and secondary esters of phosphoric acid and the half esters of sulfosuccinic acid; Sulfates of N-acylated alkanolamines, e.g. B. the sulfated amides of caprylic, pelargonic, capric, lauric, myristic or stearic acid or of lower fatty acids substituted by alkylphenoxy groups, such as octyl or nonylphenoxyacetic acid, with mono- or bis-hydroxyalkylamines, such as β-hydroxyethylamine, γ -Hydroxypropylamine, β, γ-Dih- ydroxypropylamine, bis- (β-hydroxyethyl) amine or with N-alkyl-N-hydroxyalkylamines, such as N-methyl or N-ethyl-N- (β-hydroxyethyl) amine ; Sulfated esterified polyoxy compounds, e.g. B. sulfated partially esterified polyhydric alcohols, such as the sodium salt of the sulfated monoglyceride of palmitic acid.

worin die allgemeinen Symbole wie in Formel (1) definiert sind, mit Phosphorsäure, Phosphorpentoxid oder einem Halogenid der Phosphorsäure erhalten werden. Bevorzugt ist die Umsetzung mit Phosphorpentoxid. Die Veresterung erfolgt zweckmäßig durch einfaches Vermischen der Reaktions- _'partner unter Erwärmen, z. B. auf 50-100" C. Die sauren Ester können, falls erwünscht, in die entsprechenden Salze (Alkalimetall-, Ammonium- oder Aminsalze) übergeführt werden, z. B. in üblicher Weise durch Zugabe der entsprechenden Basen, z- B. Ammoniak, Monoäthanolamin, Triäthanolamin, Alkalimetallhydroxide.The acidic phosphoric acid esters of fatty amine oxalkylation products of the formula (1) used in the process according to the invention are known and can be obtained simply by esterification of a fatty amine oxalkylation product of the formula

wherein the general symbols as defined in formula (1) can be obtained with phosphoric acid, phosphorus pentoxide or a halide of phosphoric acid. The reaction with phosphorus pentoxide is preferred. The esterification is advantageously carried out by simply mixing the reaction _'partner under heating, z. B. to 50-100 "C. If desired, the acidic esters can be converted into the corresponding salts (alkali metal, ammonium or amine salts), for example in a customary manner by adding the appropriate bases, for example Ammonia, monoethanolamine, triethanolamine, alkali metal hydroxides.

worin n" + m" die Zahl 8 ist und X einen sauren Phosphorsäurerest bedeutet, kann wie folgt vorgegangen werden:For the preparation of the compound of the formula

where n "+ m" is the number 8 and X is an acidic phosphoric acid residue, can be carried out as follows:

worin n" + m" = 8, werden bei Raumtemperatur in einem Kolben vorgelegt und unter Rühren mit einem Wasser/Eisbad auf 18 C gekühlt. Dann werden 80,94 g Phosphorpentoxid schnell zugegeben. Nach Entfernung des Kühlbades steigt die Temperatur der gelblichen Suspension auf Raumtemperatur an. Nun wird mit einem Ölbad innerhalb 2 Stunden auf 40" C und anschließend innerhalb weiterer 2 Stunden auf 60 C erwärmt. Es wird noch eine Stunde bei 60" C gerührt. Das erhaltene Produkt der Formel (6) ist bei Raumtemperatur ein gelbes, gut gießbares Gel. Die analogen Verbindungen der Formeln (6a), (6b), (6c) und (6d) (siehe Beispiele) werden ebenfalls nach der obigen Vorschrift erhalten.914.6 g of the compound of the formula

where n "+ m" = 8, are placed in a flask at room temperature and cooled to 18 ° C. with stirring with a water / ice bath. Then 80.94 g of phosphorus pentoxide are added quickly. After removing the cooling bath, the temperature of the yellowish suspension rises to room temperature. Now the mixture is heated to 40 ° C. in the course of 2 hours and then to 60 ° C. in the course of a further 2 hours. The mixture is stirred at 60 ° C. for another hour. The product of formula (6) obtained is a yellow, easily pourable gel at room temperature. The analogous compounds of the formulas (6a), (6b), (6c) and (6d) (see examples) are also obtained according to the above procedure.

The addition products of the formula (5) are known and can be obtained in a known manner from Anla tion of 2 to 30 moles of ethylene or propylene oxide to an aliphatic amine with a hydrocarbon radical of 8 to 22 carbon atoms.

The process according to the invention is expediently carried out in such a way that, for example, the brightener, an acidic phosphoric acid ester of a fatty amine oxyalkylation product of the formula (1) and, if appropriate, one or more of the above-mentioned additional auxiliaries, individually and for the respective coating liquor which is prepared in the customary manner admixed in any order and finely divided therein, for example at temperatures between 10 and 150 ° C. Alternatively, the whitener can also be mixed with an acidic phosphoric acid ester of a fatty amine oxalkylation product of the formula (1) and optionally with one or more of the above before the coating liquor is added the additional auxiliaries mentioned, advantageously with the addition of water, and the brightener preparation obtained can then, as described above, be added to the coating liquor, and paper or cardboard can then be coated with conventional coating apparatus with the finished coating composition with, for example, an air knife, a doctor knife, a brush, a roller, a doctor blade, a rod or any other coating apparatus customary in the paper industry.

The amount of compound of the formula (1) used in the process according to the invention can vary within wide limits. Even at a ratio of brightener to compound of formula (1) of 1: 0.5, positive effects are observed. This ratio is preferably 1: 1 to 15, in particular 1: 1 to 1: 3. Particularly good effects are achieved at a ratio of 1: 2. It would also be entirely possible to use more compound of the formula (1) than corresponds to the ratio 1: 5; however, this is not practical either for economic reasons or because of the associated influence on the consistency of the coating slip. The amount of optional aids (surfactants, solubilizers, polar compounds) can vary within wide limits. The ratio of brightener to these aids can be between 1: 0.1 to 1:10, depending on the type of aid used (see also examples).

The amount of brightener that is added to the coating slips is within the normal range in the paper industry. For example, amounts between 1 g and 50 g / l of coating liquor are considered, preferably those between 4 and 20 g / l. As already mentioned, the method according to the invention also allows brightener concentrations higher than they are usually used (for example 4 to 8 g / l). Without the addition of compounds of formula (1), a drop in whiteness or severe greening often occurs, for example, at concentrations of more than 10 g of brightener per liter. On the other hand, this effect is eliminated when compounds of the formula (1) are added according to the invention: with an increasing brightener concentration, the attainable degree of whiteness also increases.

The process according to the invention is suitable for the optical brightening of the coating slips usually used in the paper industry, specifically of unpigmented, but in particular pigmented coating slips. These coating slips contain a polymeric binder, an inorganic pigment (in the case of pigmented coating slips) and optionally other additives such as. B. waxes, dispersants, wetting agents or other surface-active agents, viscosity regulators, antifoams, lubricants, plasticizers and / or preservatives.

Suitable polymeric binders are the customary polymeric adhesive binder systems used in the paper industry. For example, any of the known, modified or converted types of starch, such as extra oxidized, hydrolyzed or hydroxyethylated starches, can be used. In addition to the different types and types of starch, other natural or synthetic polymeric binder systems can be used alone or in particular in the case of synthetic polymeric binders in combination with one another. Plastic dispersions based on copolymers of butadiene-styrene, acrylonitrile-butadiene-styrene, acrylic acid esters, ethylene-vinyl chloride and ethylene-vinyl acetate; or based on homopolymers such as polyvinyl chloride, polyvinylidene chloride, polyethylene, polyvinyl pyrrolidone, polyvinyl alcohol and polyvinyl acetate, and polyurethanes are suitable as binders for the coating slips to be lightened in the process according to the invention. Further degraded starch, alginates, carboxymethyl cellulose, proteins (e.g. gelatin, casein, soy protein) etc. can be used as binders.

For example, aluminum-magnesium silicates (China-Clay®), calcium carbonate, CaS04 10 H ₂ 0 (satin white), aluminum silicates and hydroxides, barium sulfate (Blancfix) or titanium dioxide or mixtures of such pigments can be used as white pigments. In addition, the coating liquors can be used to eliminate undesirable traces of metal (e.g. Fe (III)) metal-binding agents such as. B. water-soluble poly- or metaphosphates and polycarboxylic acid salts.

To obtain good flow properties, an alkaline coating liquor is used for the pigment coat. The alkaline reaction is expediently set with ammonia or with NaOH or KOH or with Na or K carbonates or borates or mixtures thereof.

As wetting agents such. B. unsulfated or sulfated higher alkanol or alkylphenol polyglycol ether with an 8 to 14 carbon atom-containing alkyl radical with 1 to 20 ethylene oxide groups. Recipes of such known coating slips to be lightened by the process according to the invention are described, for example, in JP Casey, “Pulp and Paper”; Chemistry and Chemical Technology, 2n ^d Ed, Vol. 111, p. 1648-1649 and in Mc Graw-Hill, "Pulp and Paper Manufacture", ^2d Ed., Vol 11 _n., P. 497.

The present invention further relates to the coating compositions lightened by the process according to the invention, that is to say an optical brightener of the bis-triazinylaminostilbene-2,2'-disulfonic acid series, preferably one of the formula (3), in particular one of the formula (4) and contain an acidic phosphoric acid ester of a fatty aminoxyalkylation product of the formula (1), preferably one of the formula (2).

Furthermore, in addition to the optical brightener and the acidic phosphoric acid ester of a fatty amine oxalkylation product, the coating compositions according to the invention can additionally contain nonionic or anionic surfactants, organic solubilizers and / or polar organic compounds, for. B. as organic solubilizers hydrophilic organic solvents, for example lower monohydric alcohols, polyhydric alcohols, ether alcohols, glycols, polyglycols, glycol and polyglycol ethers, amides and / or amines or as polar organic compounds dimethyl sulfoxide, dimethyl sulfone, ethylene or propylene carbonate and / or urea , or nonionic surfactants such as adducts of alkylene oxides with higher fatty acids, fatty acid amides, aliphatic alcohols, mercaptans or amines, with alkylphenols, alkylthiophenols or phenylphenols, block polymers from ethylene oxides and higher alkylene oxides, nonionic esters of the adducts with alkylene oxides, esters of polyalcohols and their addition products with ethylene oxide and reaction products from higher fatty acids with an alkanolamine and / or as anionic surfactants alkylene oxide adducts with sulfate or other acid residues, sulfates of N-acylated alkanolamines and sulfated esterified polyoxyves ties.

Finally, the present invention relates to paper and cardboard coated with coating slips according to the invention (as described above).

In the following examples, parts and percent are always parts by weight and percent by weight, unless stated otherwise.

example 1

• a) In a 2 liter beaker, 100 g of starch ("Paperol R 10") ® and 950 ml of demineralized water are heated to 80 "C within 10-15 minutes with stirring and then stirred at 80-85'C for 15 minutes A slightly cloudy, gray, colloidal solution is obtained, then the mixture is cooled to about 40 ° C., 50 ml of 4-nonylphenol 1:25, which is ethoxylated with 9.7 mol of ethylene oxide, are added and the solution is demineralized at 40 ° C. Make up to 1000 ml and shake briefly, then adjust the pH to 8-9 with concentrated ammonia.
• b) 15 ml of the starch liquor obtained according to a) are mixed with 5 ml of a brightener solution, which consists of 11.6 g of the optical brightener of the formula
  
  20 g of the acidic phosphoric acid ester of a fatty amine oxalkylation product of the formula (6), 10 g of a 4-nonylphenol ethoxylated with 9.7 mol of ethylene oxide, 15 g of ethylene glycol, 18 g of polyethylene glycol 300 and 25.4 g of water. The mass obtained is homogeneously mixed on a magnetic stirrer.
• c) After a waiting time of about 20 minutes, the coating slip obtained in b) is stirred again and strips of coating base paper prepared therewith are coated in the customary manner. In this way a paper is obtained whose whiteness is significantly higher than that of a comparison paper which is coated with a coating liquor which contains no compound of the formula (6).

Example 2

• b) 15 ml der gemäß a) erhaltenen Stärkeflotte werden mit 5 ml einer Aufhellerlösung versetzt, die 11,6 g des Aufhellers der Formel (10) in 88,4 g Wasser enthält. Die erhaltene Masse wird auf einem Magnetrührer homogen vermischt.
• c) Nach einer Wartezeit von ca. 20 Minuten wird die gemäß b) erhaltene Streichmasse nochmals gerührt und damit vorbereitete Streifen Streichrohpapier in üblicher Weise beschichtet. Man erhält auf diese Weise ein Papier, dessen Weißgrad deutlich höher ist als der eines Vergleichspapiers, das mit einer Streichflotte beschichtet ist, die keine Verbindung der Formel (6) enthält.

In a 2-1 beaker 100 g ("Paperol R 10") ® and 950 ml of demineralized water are heated to 80 ° C with stirring within 10-15 minutes and then stirred at 80-85 "C for 15 minutes a slightly cloudy, gray, colloidal solution to which 7.5 g of the acidic phosphoric acid ester of a fatty amine oxalkylation product of the formula (6) are added, after which the mixture is cooled to about 40 ° C., 50 ml of which is ethoxylated with 9.7 mol of ethylene oxide 4-Nonylphenol 1:25 added and filled with deionized water from approx. 40 "C to 1000 ml and shaken briefly. Then with conc. Ammonia adjusted a pH of 8-9.

• b) 15 ml of the starch liquor obtained according to a) are mixed with 5 ml of a brightener solution which contains 11.6 g of the brightener of the formula (10) in 88.4 g of water. The mass obtained is on a Magnetic stirrer mixed homogeneously.
• c) After a waiting time of about 20 minutes, the coating slip obtained according to b) is stirred again and strips of coating base paper prepared therewith are coated in the customary manner. In this way a paper is obtained whose whiteness is significantly higher than that of a comparison paper which is coated with a coating liquor which contains no compound of the formula (6).

Example 3

ein, so erhält man Papier mit ähnlich hohem Weißgrad.If example 1 is repeated, but instead of the brightener of the formula (10), the corresponding amount of a brightener of the following formulas is used:

, paper with a similarly high degree of whiteness is obtained.

Example 4

If example 2 is repeated, but instead of using the brightener of formula (10), the corresponding amount of a brightener of formula (11), (12), (13), (14) or (15) is used, paper with similar results high whiteness.

Example 5

• A) 20 g der Verbindung der Formel (6) 11,6 g des Aufhellers der Formel (10) 15 g Äthylenglykol 53,4 g Wasser;
• B) 10 g der Verbindung der Formel (6) 5,8 g des Aufhellers der Formel (10) 9 g Polyäthylenglykol 300 25,2 g Wasser;
• C) 10 g der Verbindung der Formel (6) 5,8 g des Aufhellers der Formel (10) 5 g eines mit 9,7 Mol Äthylenoxid äthoxylierten 4-Nonylphenols 29,2 g Wasser;
• D) 10 g der Verbindung der Formel (6) 5,8 g des Aufhellers der Formel (10) 5 g eines mit 9,7 Mol Äthylenoxid äthoxylierten 4-Nonylphenols 7,5 g Äthylenglykol 21,7 g Wasser;
• E) 10 g der Verbindung der Formel (6) 5,8 g des Aufhellers der Formel (10) 7,5 g Äthylenglykol 9 g Polyäthylenglykol 300 17,7 g Wasser

5 ml of the following brightener solutions are added to 15 ml of a starch liquor obtained according to Example 1 a):

• A) 20 g of the compound of the formula (6) 11.6 g of the brightener of the formula (10) 15 g of ethylene glycol 53.4 g of water;
• B) 10 g of the compound of the formula (6) 5.8 g of the brightener of the formula (10) 9 g of polyethylene glycol 300 25.2 g of water;
• C) 10 g of the compound of the formula (6) 5.8 g of the brightener of the formula (10) 5 g of a 4-nonylphenol ethoxylated with 9.7 mol of ethylene oxide 29.2 g of water;
• D) 10 g of the compound of the formula (6) 5.8 g of the brightener of the formula (10) 5 g of a 4-nonylphenol ethoxylated with 9.7 mol of ethylene oxide 7.5 g of ethylene glycol and 21.7 g of water;
• E) 10 g of the compound of formula (6) 5.8 g of the brightener of formula (10) 7.5 g of ethylene glycol 9 g of polyethylene glycol 300 17.7 g of water

The coating slip is finished and the paper is coated as described in Examples 1b) and 1c). In each case paper with a high degree of whiteness is obtained, which is considerably higher than that which is achieved with the individual brightener formulations A) to E), but without the compound of the formula (6).

If you replace the brightener of the formula (10) in the brightener solutions A) to E) with appropriate amounts of brightener of the formula (11), (12), (13), (14) or (15), you come to paper similarly high whiteness.

The individual components listed in the brightener solutions A) to E) can also be added individually and in any order to the coating slip, and similar results are then obtained.

Example 6

• A) 30 g der Verbindung der Formel (6) 16,7 g des Aufhellers der Formel
  
  und 53,3 g Wasser;
• B) 30 g der Verbindung der Formel (6) 16,7 g des Aufhellers der Formel (10a) 9 g Harnstoff 44,3 g Wasser;
• C) 30 g der Verbindung der Formel (6) 16,9 g des Aufhellers der Formel
  
  und 53,1 g Wasser,
• D) 30 g der Verbindung der Formel
  
  worin n"' + m"' die Zahl 12 ist und X wie in Formel (6) definiert ist, 16,9 g des Aufhellers der Formel (10 b) 53,1 g Wasser;
• E) 30 g der Verbindung der Formel
  
  worin n^IV + m^IV die Zahl 20 ist und X wie in Formel (6) definiert ist, 16,9 g des Aufhellers der Formel (10 b) 53,1 g Wasser;
• F) 30 g der Verbindung der Formel
  
  worin n" + m" die Zahl 8 ist, X wie in Formel (6) definiert ist und R_i den Kohlenwasserstoffrest des Talgfettamins bedeutet, 16,9 g des Aufhellers der Formel (10 b) 53,1 g Wasser.

5 ml each of the following brightener solutions are added to 15 ml of a starch liquor obtained according to Example 1a):

• A) 30 g of the compound of formula (6) 16.7 g of the brightener of the formula
  
  and 53.3 g water;
• B) 30 g of the compound of formula (6) 16.7 g of the brightener of formula (10a) 9 g of urea 44.3 g of water;
• C) 30 g of the compound of formula (6) 16.9 g of the brightener of the formula
  
  and 53.1 g of water,
• D) 30 g of the compound of the formula
  
  where n "'+ m"' is the number 12 and X is as defined in formula (6), 16.9 g of the brightener of formula (10 b) 53.1 g of water;
• E) 30 g of the compound of the formula
  
  wherein n ^IV + m ^{IV is} 20 and X is as defined in formula (6), 16.9 g of the brightener of formula (10 b) 53.1 g of water;
• F) 30 g of the compound of the formula
  
  where n "+ m" is the number 8, X is as defined in formula (6) and R _{i is} the hydrocarbon residue of tallow fatty amine, 16.9 g of the brightener of formula (10 b) 53.1 g of water.

The coating slip is finished and the paper is coated as described in Examples 1b) and 1c). In each case paper with a high degree of whiteness is obtained, which is considerably higher than that which is achieved with the individual brightener formulations A) to F), but without the compound of the formulas (6), (6a), (6b) or (6c).

If the brightener of the formula (10a) or (10b) in the brightener solutions A) to F) is replaced by corresponding amounts of brightener of the formula (11), (12), (13), (14) or (15), see above one comes to paper with a similarly high degree of whiteness.

The individual components listed in the brightener solutions A) to F) can also be added individually and in any order to the coating slip, and similar results are then obtained.

Example 7

A. 15 ml of a starch liquor obtained according to Example 1a) are added 1.1 g of the brightener of the formula (15), 0.85 g of the acid ester of the formula (6) and 3 g of water. The mass obtained is homogeneously mixed on a magnetic stirrer.

B. 15 ml of a starch liquor obtained according to Example 1a) are mixed with 1.1 g of the brightener of the formula (15), 0.51 g of the acid ester of the formula (6c) and 3.4 g of water. The mass obtained is homogeneously mixed on a magnetic stirrer.

C. Process B is repeated, but instead of the acidic ester of the formula (6c), the same amount of an ester of the formula (6a) is used.

D. Process B is repeated, but instead of the acidic ester of the formula (6c), the same amount of an ester of the formula (6b) is used.

After a waiting time of approx. 20 minutes, the coating slips obtained according to A to D are stirred again and strips of coating base paper thus prepared are coated in the usual way. In this way papers are obtained whose whiteness is significantly higher than that of a comparison paper which is coated with a coating liquor which does not contain an acidic ester of the formula (6), (6a), (6b) or (6c).

Example 8

• a) 150 ml of an aqueous plastic dispersion of a copolymer of acrylic acid ester and styrene (free from plasticizers and solvents), 100 ml of sodium salt of a polycarboxylic acid (solution 1:50), 500 ml of China Clay Dinkie A® and 50 ml of one with 9 , 7 mol of ethylene oxide ethoxylated 4-nonylphenol (solution 1:25) in 600 ml of water. The mixture is stirred until a homogeneous coating liquor is obtained. The pigmented coating liquor thus produced is sieved (nickel sieve), deaerated and freed from coarser impurities.
• b) 15 ml of the pigment coating liquor obtained according to a) are mixed with 5 ml of a brightener solution, which consists of 11.6 g of the brightener of the formula (10), 20 g of the acidic phosphoric acid ester of a fatty amine oxyalkylation product of the formula (6), 10 g of a with 9.7 mol of ethylene oxide ethoxylated 4-nonylphenol, 15 g of ethylene glycol, 18 g of polyethylene glycol 300 and 25.4 g of water. The mass obtained is homogeneously mixed on a magnetic stirrer.
• c) After a waiting time of about 20 minutes, the coating slip obtained according to b) is stirred again and strips of coating base paper prepared therewith are coated in the customary manner. In this way a paper is obtained whose whiteness is significantly higher than that of a comparison paper which is coated with a coating liquor which contains no compound of the formula (6).

Example 9

• a) 14 g of the compound of formula (6), 150 ml of an aqueous plastic dispersion of a copolymer of acrylic acid ester and styrene (free from plasticizers and solvents), 100 ml of sodium salt of a polycarboxylic acid (solution 1:50), 500 ml of China Clay Dinkie AC, and 50 ml of a 4-nonylphenol (solution 1:25) ethoxylated with 9.7 mol of ethylene oxide in 600 ml of water. The mixture is stirred until a homogeneous coating liquor is obtained. The pigmented coating liquor thus produced is sieved (nickel sieve), deaerated and freed from coarser impurities.
• b) 15 ml of the pigment coating liquor obtained according to a) are mixed with 5 ml of a brightener solution which contains 11.6 g of the brightener of the formula (10) in 88.4 g of water. The mass obtained is homogeneously mixed on a magnetic stirrer.
• c) After a waiting time of about 20 minutes, the coating slip obtained according to b) is stirred again and strips of coating base paper prepared therewith are coated in the customary manner. In this way a paper is obtained whose whiteness is significantly higher than that of a comparison paper which is coated with a coating liquor which contains no compound of the formula (6).

Example 10

If Example 8 is repeated, but instead of using the brightener of the formula (10), the corresponding amount of a brightener of the formula (11), (12), (13), (14) or (15) is used, paper with similar is obtained high whiteness.

Example 11

If Example 9 is repeated, but instead of using the brightener of formula (10), the corresponding amount of a brightener of formula (11), (12), (13), (14) or (15) is used, paper with similar results high whiteness.

Example 12

5 ml each of the brightener solutions A) to E) defined in Example 5 are added to 15 ml of a pigment coating liquor obtained according to Example 8a). The coating slip is finished and the paper is coated as described in Examples 8b) and 8c). In each case paper with a high degree of whiteness is obtained, which is considerably higher than that which is achieved with the individual brightener formulations A) to E), but without the compound of the formula (6).

If you replace the brightener of the formula (10) in the brightener solutions A) to E) with appropriate amounts of brightener of the formula (11), (12), (13), (14) or (15), you come to paper similarly high whiteness.

Example 13

a) 600 ml of demineralized water, 10 ml of conc. Ammonia and 35 g of casein are placed in a 2 liter beaker and heated with stirring to 70 ° C. in the course of 10 minutes. The mixture is stirred for a further 15 minutes at 70-75 ° C. A cloudy, sand-colored, colloidal solution is obtained Casein solution cooled to 30 ° C. is added to a mixture of 50 ml of the sodium salt of a polycarboxylic acid (aqueous solution 1:50) and 400 g of china clay SPS ^O. The mixture obtained is slowly stirred for 3 minutes Any pigment adhering to the wall is scraped off with a scraper, then slowly stirred for another 2 minutes, then 3 ml of concentrated ammonia and 80 ml of styrene-butadiene latex are added with stirring and the mixture is slowly stirred for a further 3 minutes 9.7 mol of ethylene oxide ethoxylated 4-nonylphenol (1:25) were added and the mixture was stirred for about 15 seconds again.

The fleet thus produced is vented through a nickel sieve and freed of agglomerates and coarser impurities. The mass is then placed in a 1 liter Erlenmeyer flask and adjusted to a weight of 1260 g per liter with deionized water.

b) 15 ml of the art print coating liquor obtained in accordance with a) are mixed with 5 ml of a brightener solution which consists of 11.6 g of the brightener of the formula (10), 20 g of the acidic phosphoric acid ester of a fatty aminoxalkylation product of the formula (6), 10 g of one with 9 , 7 moles of ethylene oxide ethoxylated 4-nonylphenol, 15 g of ethylene glycol, 18 g of polyethylene glycol 300 and 25.4 g of water. The mass obtained is homogeneously mixed on a magnetic stirrer.

c) After a waiting time of about 20 minutes, the coating slip obtained according to b) is stirred again and strips of coating base paper prepared therewith are coated in the customary manner. In this way a paper is obtained whose whiteness is significantly higher than that of a comparison paper which is coated with a coating liquor which contains no compound of the formula (6).

Example 14

Example 13 is repeated, but 14 g of the compound of the formula (6) were additionally added in the preparation of the art print coating slip according to Example 13a). 15 ml of the coating slip otherwise prepared as described in Example 13a) are then mixed with 5 ml of a brightener solution consisting of 11.6 g of the brightener of the formula (10) and 88.4 g of water. Further workup is carried out as described in Example 13. A paper with a much higher degree of whiteness than that obtained by coating with a corresponding coating liquor which does not contain the compound of the formula (6) is likewise obtained.

In Examples 13 and 14, those of the formulas (11), (12), (13), (14) and (15) can be used with equal success instead of the brightener of the formula (10).

Replacing the acidic ester of formula (6) with one of formula (6a), (6b) or (6c) in the procedures of Examples 8 to 14 also gives well-lightened paper which has a higher degree of whiteness than Paper that is coated with a coating liquor that does not contain such an acid ester.

Claims (12)

1. A process for obtaining coating compositions of improved whiteness for coating paper or cardboard using fluorescent whitening agents of the bis-triazinylaminostilbene-2,2'-disulfonic acid series, which process comprises adding to the coating compositions, in addition to the respective fluorescent whitening agent, an acid phosphoric acid ester of an oxyalkylated fatty amine of the formula

or an alkali metal salt, ammonium salt or amine salt thereof, wherein R is an aliphatic hydrocarbon radical of 8 to 22 carbon atoms, Y₁ and Y₂ are both hydrogen, or one of Y, and Y₂ is hydrogen and the other is methyl, X is the acid radical of phosphoric acid, the acid hydrogen atoms of which radical can be replaced by alkali metal ions, ammonium ions or amine salt ions, and m and n are integers, the sum of which is 2 to 30.

2. A process according to claim 1, which comprises the use of an acid phosphoric acid ester of an oxyalkylated fatty amine, of the formula

wherein R' is an alkyl or alkenyl radical of 10 to 18 carbon atoms, preferably the lauryl radical or the hydrocarbon radical of tallow fatty amine, X' is the acid radical of phosphoric acid, the acid hydrogen atoms of which radical can also be replaced by alkali metal ions or ammonium ions, and n' and m' are integers, the sum of which is 4 to 20, especially 6 to 8.

3. A process according to claim 1, which comprises the use of a fluorescent whitening agent of the formula

wherein R₁ and R₂ are

or

and M is hydrogen, an alkali metal ion, an ammonium ion or an amine salt ion, preferably of a fluorescent whitening agent of the formula

wherein Riis

or

R_z is

or

and M' is hydrogen or an alkali metal ion, an ammonium, diethanolammonium or triethanolammonium ion.

4. A process according to any one of claims 1 to 3, which comprises adding to the coating composition, besides fluorescent whitening agent and acid phosphoric acid ester of an oxyalkylated fatty amine, also a non-ionic or anionic surfactant, an organic solubiliser and/or a polar organic compound.

5. A process according to claim 4, which comprises adding to the coating composition, as solubiliser, a hydrophilic organic solvent such as a lower monohydric alcohol, a polyhydric alcohol, an ether alcohol, a glycol, polyglycol, glycol ether or polyglycol ether, an amide or amine, and/or, as polar organic compound, dimethylsulfoxide, dimethyl methanephosphonate, dimethyl sulfone, sulfolane, ethylene carbonate or propylene carbonate, urea or a substituted urea.

6. A process according to claim 4, which comprises adding to the coating composition, as non-ionic surfactant, an adduct of an alkylene oxide with a higher fatty acid, fatty acid amide, aliphatic alcohol, mercaptan or amine, with an alkylphenol, alkylthiophenol or phenylphenol, a copolymer of ethylene oxide and a higher alkylene oxide, a non-ionic ester of an adduct of an alkylene oxide, an ester of a polyalcohol, a N-acylated alkanolamine or an adduct thereof with ethylene oxide, and a reaction product of a higher fatty acid with an alkanolamine and/or, as anionic surfactant, an alkylene oxide adduct containing sulfate or other acid radicals, a sulfate of a N-acylated alkanolamine, or a sulfated esterified polyoxy compound.

7. A process according to any one of claims 1 to 6, wherein the fluorescent whitening agent is mixed with the acid phosphoric acid ester of an oxyalkylated fatty amine and, if desired, with optional assistants as defined in claims 4 to 6 and, optionally, water, and this mixture is mixed with the coating composition.

8. A process according to any one of claims 1 to 6, which comprises adding to the coating composition, independently of one another and separately, the fluorescent whitening agent, the acid phosphoric acid ester of an oxyalkylated fatty amine and, if desired, the optional assistants as defined in claims 4 to 6.

9. A whitened coating composition for coating paper and cardboard, said composition containing a fluorescent whitening agent of the bis-triazinylaminostilbene-2,2'-disulfonic acid series, preferably of the formula (3) and, most preferably, of the formula (4) according to claim 3, and an acid phosphoric acid ester of an oxyalkylated fatty amine, of the formula (1), preferably of the formula (2), according to claims 1 and 2.

10. A coating composition according to claim 9 which, in addition to containing the fluorescent whitening agent and the acid phosphoric acid ester of an oxyalkylated fatty amine, contains a non-ionic or anionic surfactant, preferably as defined in claim 6, an organic solubiliser and/or a polar organic compound, preferably as defined in claim 5.

11. Paper or cardboard coated with a coating composition as defined in claim 9 or 10.