EP1300513A2 - Use of solid preparations of optical brighteners for optically brightening paper - Google Patents

Abstract

Solid whitener preparation comprises (a) 85-99.9 weight percent (wt.%) optical brightener(s) and (b) 0.1-15 (preferably 0.5-10) wt.% residual moisture, where more than 90 (preferably more than 95, especially more than 98) wt.% of the preparation consists of components (a) and (b).

Description

The invention relates to the use of solid, particulate brightener preparations for the optical brightening of paper.

The optical brightening of paper comes from the paper pulp, in the size press and in the paper line for use. When lightening paper in particular of the paper pulp, ecological aspects, e.g. with the meaning of Avoidance of organic wastewater loads and economic aspects, e.g. in the In terms of cost-effective processes. State of the art the use of liquid brightener formulations, be it in the form of solutions or of suspensions, also called slurries or slurries.

Stilbene brighteners substituted by sulfo groups are preferred, in particular Triazinylstilbene brighteners are used, which are often characterized by good substantivity on the one hand distinguish, but accordingly by a limited solubility in cold water on the other hand are marked. In purely aqueous solutions, they already tend to low concentrations to crystalline precipitates, in particular as a result of Hydration of the brightener compounds. Storage-stable aqueous solutions such as these e.g. are described in DE-A-2 928 053, therefore also contain considerable Amounts of fillers and organic solvents.

DE-A-2 715 864 therefore uses "slurries", ie suspensions, as a way out optical brightener described by mixing the water-moist brightener press cake with dispersants and optionally electrolytes, organic Extender agents (urea etc.) and gelling agents are produced. This However, as disclosed in EP-A-385 374, slurries are longer Period not stable to sedimentation. In EP-A-385 374 are therefore aqueous Suspensions of the optical brighteners in the form of their free acids or salts for the Use in liquid detergents described by adding an anionic Polysaccharides (thickeners) can be stabilized against sedimentation. Similar, Formulations of the free containing anionic polyhydroxy compounds Acids of optical brighteners are described in EP-A-835 906 for use in Paper described. However, these suspensions have in terms of their economic Use, especially for lightening paper in bulk, still Disadvantage. The whitening crystals of a wet grinding have to be of a particle size of <20 µm, especially <10 µm and the solubility in Water may only be obtained by adding alkali.

DE-A-2 715 864 also describes the advantages with regard to the dust behavior of Slurries over dry powders by drying and grinding of the water-moist press cake are obtained.

DE-A-3 523 207 describes low-dust solid brightener preparations for use described in textile dye baths, which are spray-dried by mixing optical brightener formulation with an aromatic carboxylic acid ester or Fatty acid polyol esters are obtained, and are characterized by good hot water solubility Mark (80 ° C).

Surprisingly, it has now been found that solid, particulate brightener preparations, which are preferably largely or completely free of crystalline brightener particles, especially their hydrate forms, are one in comparison to the above State of the art improved dissolution rate in water, especially in Cold water, preferably at 10 to 30 ° C, and therefore for continuous and discontinuous lightening of paper in the above-mentioned processes are suitable. Especially for continuous application in the pulp (pulp) in papermaking also have more concentrated solutions above 5% sufficient stability against precipitation for the duration of the application.

a) 85 bis 99,9 Gew.-% wenigstens eines optischen Aufhellers und

b) 0,1 bis 15 Gew.-%, insbesondere 0,5 bis 10 Gew.-% Restfeuchte bezogen auf die feste Präparation

dadurch gekennzeichnet, dass die Präparation zu mehr als 90 Gew.-%, bevorzugt mehr als 95 Gew.-%, insbesondere mehr als 98 Gew.-% aus den Komponenten a) und b) besteht.The invention therefore relates to the use of solid, particulate brightener preparations for optically brightening paper, for example in bulk or in a line containing

a) 85 to 99.9% by weight of at least one optical brightener and

b) 0.1 to 15 wt .-%, in particular 0.5 to 10 wt .-% residual moisture based on the solid preparation

characterized in that the preparation consists of more than 90% by weight, preferably more than 95% by weight, in particular more than 98% by weight, of components a) and b).

Within the scope of the application, a solubility of> 0.1 g / l, preferably> 1 g / l, in particular> 5 g / l at 20 ° C understood.

worin
R¹, R² und R³ unabhängig voneinander Phenoxy; mono- oder disulfoniertes Phenoxy; Phenylamino; mono- oder disulfoniertes Phenylamino; Phenylamino substituiert durch C₁-C₃-Alkyl, Cyano, Halogen, COOR, CONH-R, NH-COR, SO₂NH-R, O-R; Morpholino; Piperidino; Pyrrolidino; -OC₁-C₄-Alkyl; -NH(C₁-C₄-Alkyl); -N(C₁-C₄-Alkyl)₂; -NHC₂-C₄-Alkylen-OR; -N(C₂-C₄-Hydroxyalkyl)₂; -NHC₂-C₄-Alkylen-O-C₂-C₄-Alkylen-OR;
eine Aminosäure oder ein Aminosäureamid, von deren Aminogruppe ein Wasserstoffatom entfernt wurde; -NHCH₂CH₂OH; -N(CH₂CH₂OH)₂; -N(CH₃)(CH₂CH₂OH); -NH₂;
-OCH₃; -S-C₁-C₄-Alkyl; -S-Aryl; -Cl; -NH-CH₂CH₂SO₃H; -N(CH₂CH₂SO₃H)₂ oder -N(CH₂CH₂OH)CH₂CH₂CONH₂ bedeuten, und

R

H oder C₁-C₃-Alkyl und M den Rest eines Alkali-, Erdalkali, Ammonium- oder Aminsalzes bedeutet. Unter Aminsalzionen sind solche der Formel H⊕NR⁴R⁵R⁶ bevorzugt, in denen R⁴, R⁵ und R⁶ unabhängig von einander Wasserstoff, Alkyl, Alkenyl, Hydroxyalkyl, Cyanoalkyl, Halogenalkyl oder Phenylalkyl bedeuten oder worin R⁴ und R⁵ zusammen die Ergänzung zu einem 5 bis 7-gliedrigen gesättigten Stickstoffheterozyklus darstellen, der noch zusätzlich ein Stickstoff- oder Sauerstoffatom als Ringglied enthalten kann, beispielsweise einen Piperidin, Piperazin, Pyrrolidin-, Imidazolin- oder Morpholinring, während R⁶ für Wasserstoff steht.

The optical brighteners of component a) are preferably compounds from the group of 4,4'-bis (triazinylamino) -stilbene-2,2'-disulfonic acids, 4,4'-bis (triazol-2-yl) -stilbene -2,2'-disulfonic acids, 4,4'-dibenzofuranyl biphenyls, 4,4 '- (diphenyl) -stilbenes, bis- (benzoxazol-2-yl) derivatives, bis- (benzimidazol-2-yl) - derivatives, coumarins, pyrazolines, naphthalimides, triazinyl-pyrenes, 2-styryl-benzoxazoles or -naphthoxazoles, benzimidazole-benzofurans or -oxanilides. These are preferably brighteners from the group of the compounds containing sulfo and / or carboxyl groups, in particular from the group of stilbene compounds, very particularly distilbenes and triazinylflavonates of the general formula (I)

wherein
R ¹ , R ² and R ^{3 are} independently phenoxy; mono- or disulfonated phenoxy; phenylamino; mono- or disulfonated phenylamino; Phenylamino substituted by C ₁ -C ₃ alkyl, cyano, halogen, COOR, CONH-R, NH-COR, SO ₂ NH-R, OR; morpholino; piperidino; pyrrolidino; -OC ₁ -C ₄ alkyl; -NH (C ₁ -C ₄ alkyl); -N (C ₁ -C ₄ alkyl) ₂ ; -NHC ₂ -C ₄ alkylene-OR; -N (C ₂ -C ₄ hydroxyalkyl) ₂ ; -NHC ₂ -C ₄ alkylene-OC ₂ -C ₄ alkylene-OR;
an amino acid or an amino acid amide from whose amino group a hydrogen atom has been removed; -NHCH ₂ CH ₂ OH; -N (CH ₂ CH ₂ OH) ₂ ; -N (CH ₃ ) (CH ₂ CH ₂ OH); -NH ₂ ;
-OCH ₃ ; -SC ₁ -C ₄ alkyl; -S-aryl; -Cl; -NH-CH ₂ CH ₂ SO ₃ H; -N (CH ₂ CH ₂ SO ₃ H) ₂ or -N (CH ₂ CH ₂ OH) CH ₂ CH ₂ CONH ₂ , and

R

H or C ₁ -C ₃ alkyl and M represents the remainder of an alkali, alkaline earth, ammonium or amine salt. Preferred amine salt ions are those of the formula H⊕NR ⁴ R ⁵ R ⁶ in which R ⁴ , R ⁵ and R ⁶ independently of one another are hydrogen, alkyl, alkenyl, hydroxyalkyl, cyanoalkyl, haloalkyl or phenylalkyl or in which R ⁴ and R ⁵ together represent the addition to a 5 to 7-membered saturated nitrogen heterocycle which may additionally contain a nitrogen or oxygen atom as a ring member, for example a piperidine, piperazine, pyrrolidine, imidazoline or morpholine ring, while R ^{6 is} hydrogen.

Bevorzugte Aminosäurereste leiten sich z.B. ab von Glycin, Sarcosin, β-Alanin, Asparaginsäure oder Iminodiessigsäure.In particular, R ¹ , R ² and R ³ independently of one another denote -NH ₂ , -NH-CH ₃ , -NH-C ₂ H ₅ , -N (CH ₃ ) ₂ , -N (C ₂ H ₅ ) ₂ , -NH -CH ₂ CH ₂ OH, -NH-C ₂ -C ₄ -hydroxyalkyl, -N (C ₂ -C ₄ -hydroxyalkyl) ₂ -NH-CH ₂ CH ₂ SO ₃ H; -NH-CH ₂ -CH ₂ -O-CH ₂ -CH ₂ -OH, -OCH ₃ , -OCH (CH ₃ ) ₂ , -O-CH ₂ -CH ₂ -O-CH ₃ , -N (CH ₂ -CH ₂ -OH) ₂ , -N (CH ₂ -CHOH-CH ₃ ) ₂ , morpholino, -SCH ₃ , -N (CH ₂ -CH ₂ -OH) CH ₂ -CH ₂ -CONH ₂ and one of the following leftovers

Preferred amino acid residues are derived, for example, from glycine, sarcosine, β-alanine, aspartic acid or iminodiacetic acid.

M is preferably H, Na, Li, K, Ca, Mg, ammonium or ammonium, which is mono-, di-, tri- or terasubstituted by C ₁ -C ₄ alkyl, C ₂ -C ₄ hydroxyalkyl or a mixture it.

R¹ und R²

für -N(CH₂-CH₂-OH)₂ und

R³

für

stehen und

M

die obige Bedeutung hat, insbesondere für Na⁺ oder K⁺ steht.

Optical brighteners of the formula (I) in which

R ¹ and R ²

for -N (CH ₂ -CH ₂ -OH) ₂ and

R ³

For

stand and

M

has the above meaning, in particular stands for Na ⁺ or K ⁺ .

Optical brighteners from the distilbene series, such as them, can also be used are described for example in EP-A-0 385 374, and cationic brighteners. Brighteners may also be used, which are obtained by cationizing anionic ones, in particular brighteners containing sulfo and / or carboxyl groups, for example by means of polymeric quaternary ammonium compounds can be obtained. Such brighteners are e.g. in WO-A-9967317.

The solid preparations to be used according to the invention contain as a component b) water in the form of residual moisture. The amount of water is under residual moisture understood as moisture, based on the solid preparation, comprehensively free Water, trapped water and adsorbed water, not crystal water (i.e. water stoichiometrically integrated in a crystal structure) or constitutional water [see Widmann, Riesen: "Thermoanalyse", Hüthigverlag, Heidelberg 1984]. The solid brightener preparations to be used according to the invention are preferred X-ray amorphous.

If appropriate, the solid brightener preparations can contain further auxiliaries, preferably in an amount of less than 10% by weight, based on the preparation, contain; as such e.g. to be mentioned: formulation aids such as fillers, blending agents, surfactants and / or defoamers, and organic thickeners or protective colloids, preservatives, dedusting agents and Electrolytes. However, the solid Aulheller preparations preferably contain from ecological For this reason, only very small proportions of organic additives, auxiliary agents and / or impurities, in particular less than 5% by weight in total based on brightener of component a), very particularly less than 2% by weight.

Examples of electrolytes are sodium chloride, sodium sulfate, sodium carbonate, or one of the corresponding potassium salts or mixtures of the above Substances. The amount of electrolyte can be less than or equal to 2% by weight, preferably 0.001 to 2 wt .-%, based on the total weight of the solid preparation, in particular 0.001 to 0.5 wt .-%.

A) sulfonierten Aromaten

B) Aldehyden und/oder Ketonen und gegebenenfalls

C) einer oder mehrerer Verbindungen aus der Gruppe der nicht sulfonierten Aromaten, Harnstoff und Harnstoffderivaten.

In particular, the solid brightener preparations to be used according to the invention can contain formulation auxiliaries of component c), preferably 0.1 to 5% by weight, based on the solid preparation, of at least one condensation product based on

A) sulfonated aromatics

B) aldehydes and / or ketones and optionally

C) one or more compounds from the group of unsulfonated aromatics, urea and urea derivatives.

As sulfonated aromatics of Comp. A) are also in the context of this application understood sulfomethylated aromatics. Preferred sulfonated aromatics are: Naphthalenesulfonic acids, phenolsulfonic acids, dihydroxybenzenesulfonic acids, sulfonated Ditolyl ether, sulfomethylated 4,4'-dihydroxydiphenyl sulfone, sulfonated diphenylmethane, sulfonated biphenyl, sulfonated hydroxybiphenyl, especially 2-hydroxybiphenyl, sulfonated terphenyl or benzenesulfonic acids.

Aldehydes and / or ketones of component B) include, in particular, aliphatic, cycloaliphatic as well as aromatic in question. Aliphatic are preferred Aldehydes, with particular preference formaldehyde and other aliphatic aldehydes with 3 to 5 carbon atoms.

Examples of unsulfonated aromatics of component C) are phenol, Cresol, 4,4'-dihydroxydiphenylsulfone or dihydroxydiphenylmethane in question.

As urea derivatives, for example, dimethylol urea, melamine or Guanidine can be called.

A) wenigstens einem sulfonierten Aromaten, ausgewählt aus der Gruppe von Phenolsulfonsäuren, Dihydroxybenzolsulfonsäuren, sulfomethyliertes 4,4'-Dihydroxydiphenylsulfon, sulfoniertes Diphenylmethan, sulfoniertes Biphenyl, sulfoniertes Hydroxybiphenyl, insbesondere 2-Hydroxybiphenyl, sulfoniertes Terphenyl und Benzolsulfonsäuren, insbesondere Naphthalinsulfonsäuren und sulfonierte Ditolylether,

B) Formaldehyd und gegebenenfalls

C) einer oder mehreren Verbindungen, ausgewählt aus der Gruppe von Phenol, Kresol, 4,4'-Dihydroxydiphenylsulfon, Dihydroxydiphenylmethan, Harnstoff, Dimethylolharnstoff, Melamin und Guanidin

eingesetzt.The preferred condensation product of component c) is one based on

A) at least one sulfonated aromatic, selected from the group of phenolsulfonic acids, dihydroxybenzenesulfonic acids, sulfomethylated 4,4'-dihydroxydiphenyl sulfone, sulfonated diphenylmethane, sulfonated biphenyl, sulfonated hydroxybiphenyl, especially 2-hydroxybiphenyl, sulfonated terphenyl acids and benzenesulfonyl sulfonic acids, especially benzenesulfonyl sulfonic acids,

B) formaldehyde and optionally

C) one or more compounds selected from the group of phenol, cresol, 4,4'-dihydroxydiphenylsulfone, dihydroxydiphenylmethane, urea, dimethylolurea, melamine and guanidine

used.

The condensation product preferably obtained in the condensation preferably has an average degree of condensation of 1 to 150, particularly preferred from 1 to 20, in particular from 1 to 5.

The condensation products of component c) can be in the form of an aqueous solution or Suspension or as a solid, for example as a powder or granules, preferably as spray-dried powder or granules.

Preferred condensation products of component c) have an inorganic one Salinity below 10% by weight, preferably below 5% by weight, in particular below 1 wt .-%, based on the aqueous solution or suspension used Component or based on the solid of component c) used.

It is also preferred to have residual monomer-low to residual monomer-free condensation products to use component c).

"Low monomer" means a residual monomer content of less than 30% by weight, preferably less than 20% by weight, based on the condensation product, particularly preferably <10% by weight, preferably <5% by weight. Under In this context, residual monomers are used to produce the condensation product understood reactants used.

Such low salt and low residual monomer condensation products are for example known from EP-A 816 406.

The condensation products of component c) can be produced in this way, for example that the sulfonated aromatics of component A) optionally in a mixture with unsulfonated aromatics of component C) by reacting the underlying aromatics with a sulfonating agent preferably sulfuric acid, especially concentrated sulfuric acid, chlorosulfonic acid, Amidosulfonic acid or oleum.

1 mol of the aromatics on which component A) is based are preferred 0.4 to 3.2 mol, in particular 0.8 to 1.6 mol, of sulfonating agent are used.

The condensation then takes place with aldehydes and / or ketones of the components B), preferably formaldehyde, optionally together with others Compounds of component C). The condensation is preferably carried out in aqueous Solution at a pH of 0 to 9. Here, preferably per mol of sulfonated aromatics A) or per mole of a mixture of sulfonated aromatics of component A) and unsulfonated aromatics of component C) 0.4 to 1.5 mol, in particular 0.4 to 1.0 mol of component B) are used.

This may be followed by the neutralization of the sulfonic acid condensation product component c) with a base.

The separation of the inorganic acid or its salts and the reduction the residual monomer content can, for example, by means of membrane separation processes be performed. The preferred membrane separation processes are Ultrafiltration, diffusion dialysis or electrodialysis in question.

Those used in membrane separation processes, preferably in ultrafiltration In a preferred embodiment, membranes have a molecular weight cut-off (MWCO) of 1,000 to 10,000 daltons.

The separation of the inorganic acid using a membrane separation process is preferably carried out by diafiltration with acid-stable ultra or Cross-flow filtration nanofiltration membranes. As suitable membranes Examples include polyhydantoin membranes such as those found in EP-A 65 20 44 are known.

Preferred membranes for this purpose have a MWCO level of 2,000 to 10,000 daltons. If necessary, concentration is carried out simultaneously in this process step.

In a particular embodiment, the solid brightener preparations to be used according to the invention contain a component d) from the group of inorganic solids, such as, for example, sheet silicates such as bentonite or montmorillonite, optionally hydrophobicized, highly disperse, amorphous pyrogenic silicic acids, highly disperse silica sols, very fine, optionally hydrophobicized kaolin or highly disperse aluminum oxide ; In particular, component d) has a specific surface area [BET method] of 2 to 1,500, preferably 10 to 800 m ² / g.

The brightener preparations can also contain organic thickeners contain.

Suitable thickeners are those from the group of anionic or non-ionic organic water-soluble polymers to name the following Can also be understood as protective colloids for solid brightener preparations can. Organic thickeners, which are preferred, are particularly preferred have a solubility in water of> 100 g / l at 20 ° C.

A compound is preferably used as the organic thickener, whose 4% aqueous solution has a viscosity of ≥ 2 mPa.s at 20 ° C.

• Dextrine oder Cyclodextrine,
• Stärke und Stärkederivate, insbesondere abgebaute oder teilabgebaute Stärke,
• anionische Polyhydroxyverbindungen, insbesondere Xanthan oder Carboxymethylcellulose
• Cellulosederivate wie z.B. Methylcellulose, insbesondere Hydroxymethyl-, Hydroxyethyl- oder Hydroxypropylcellulose,
• partiell hydrolysierte Polymerisate von Vinylacetat, vorzugsweise Polyvinylalkohol, mit einem Hydrolysegrad von mehr als 70% und/oder Vinylalkohol-Copolymerisate, vorzugsweise Copolymere aus Vinylacetat und Alkylvinylester, die partiell oder vollständig verseift sind, sowie Polyinylalkohol selbst,
• Polymerisate von N-Vinylpyrrolidon, oder Copolymerisate mit Vinylestern,
• Polyacrylamide (vorzugsweise nicht ionisch oder anionisch).

Preferred organic thickeners are compounds selected from the following groups:

• Dextrins or cyclodextrins,
• Starch and starch derivatives, especially degraded or partially degraded starch,
• anionic polyhydroxy compounds, especially xanthan or carboxymethyl cellulose
• Cellulose derivatives such as methyl cellulose, especially hydroxymethyl, hydroxyethyl or hydroxypropyl cellulose,
• partially hydrolyzed polymers of vinyl acetate, preferably polyvinyl alcohol, with a degree of hydrolysis of more than 70% and / or vinyl alcohol copolymers, preferably copolymers of vinyl acetate and alkyl vinyl ester, which are partially or completely saponified, and also polyvinyl alcohol itself,
• Polymers of N-vinylpyrrolidone, or copolymers with vinyl esters,
• Polyacrylamides (preferably non-ionic or anionic).

Starch, derivatized starch and in particular are preferred as thickeners degraded starch in question.

Degraded starch is obtained, for example, by e.g. native potato, Wheat, corn, rice or tapioca starch an oxidative, thermal, enzymatic or hydrolytic degradation. Oxidative degradation is preferred here Starches, potato starch oxidatively degraded with hypochlorite is particularly preferred.

Dextrins and cyclodextrins are also particularly suitable. As dextrins are preferably white dextrins, yellow dextrins and maltodextrins with a Cold water solubility of greater than 50% by weight, preferably greater than 90%, measured at 10 g to 200 ml of water at 20 ° C understood.

Preferred cyclodextrins are those of the α-CD type with 6 glucopyranose units, β-CD with 7 glucopyranose units and γ-CD with 8 glucopyranose units as well as branched AB, AC, AD-diclosyl-CD and mixtures of the dextrins mentioned.

Polysaccharides, in particular, come as preferred anionic polyhydroxy compounds Xanthan and carboxymethyl cellulose in question.

As cellulose derivatives, methyl cellulose, Hydroxymethyl cellulose, hydroxyethyl and propyl cellulose can be used.

In particular, at least partially hydrolyzed (saponified) come as thickeners Polymers and copolymers of vinyl acetate, which completely in water dispersible, preferably completely soluble, in question. Are preferred hydrolyzed polymers and copolymers of vinyl acetate with a degree of hydrolysis from 70 to 97%, preferably from 80 to 92%, a molecular weight of 1000 to 150,000, preferably 2000 to 100,000 g / mol and an outlet viscosity (determined on a 4% aqueous solution at 20 ° C) from 2 to 35 mPa.s, preferably 2 to 10 mPa.s.

Partially hydrolyzed polyvinyl alcohols and polyvinyl alcohol are particularly preferred self.

Copolymers of vinyl acetate are used in particular as thickeners fully or partially hydrolyzed vinyl alcohol copolymers understood, in particular fully hydrolyzed Copolymers of alkyl vinyl ester and vinyl acetate with a proportion of alkyl vinyl ester of preferably 5 to 20 mol%, very particularly copolymers of alkyl vinyl acetate and vinyl acetate.

Homopolymers and copolymers of N-vinylpyrrolidone also come as thickeners in question that completely disperse in water.

The molecular weight of the homo- and copolymers of N-vinylpyrrolidone is preferably 2,000 to 1,200,000, preferably 10,000 to 150,000 g / mol.

Homopolymers of N-vinylpyrrolidone and copolymers are very particularly preferred with vinyl esters and Na methacrylate.

The brighteners of component a), in particular of the general formula (I), are either known or can be prepared by methods known per se and are usually as free acid or as its salts, preferably alkali metal salts used.

The solid brightener preparations are preferably produced by Drying a concentrated solution of the brighteners described, if necessary together with the auxiliary substances mentioned.

The process for producing the solid brightener preparations is, for example characterized in that the optical brighteners of component a) are preferred in solid form as finished or unfinished powder, granules or as water-moist Press cake, in an aqueous medium, optionally together with a part of components c) and / or d) and, if appropriate, further additives, completely dissolves and then dries.

An aqueous medium is preferably used which has a pH of 6.5 to 12, in particular from 7.5 to 12. Generally a temperature from 15 to 98 ° C, preferably from 40 to 98 ° C, in particular from 60 to 95 ° C for Achieved a complete solution. If necessary, clarification filtration the solution to separate unwanted by-products (e.g. triazines) to be required.

Subsequently, if appropriate, the aqueous solution is preferably applied to a pH from 6.5 to 10, in particular 7.5 to 9.5, adjusted and dried in the transferred brightener preparation according to the invention. As a suitable method for the drying is in particular spray drying, preferably single-component spray drying using high pressure or swirl chamber nozzles or spray drying Atomizing disks, freeze drying with upstream or downstream granulation or dry processing, spray freeze drying, build-up granulation, for example after the plate or drum granulation process, if necessary with partial pre-dried product, fluid bed drying and granulation, mixer agglomeration and drying, if necessary in combination with fluidized bed or Fluid bed drying. There are also processes such as mixed agglomeration in suspension with subsequent fluidized bed or fluid bed drying, Granulation by means of paste shaping and subsequent drying and crushing or pelleting and steam jet agglomeration in question. Combinations of the methods mentioned are also possible.

Spray drying processes using high-pressure or swirl chamber nozzles, spray drying with integrated and / or downstream Fluid bed agglomeration and / or drying, the build-up granulation using the plate process and fluid bed granulation and drying.

In particular, the solid brightener preparations to be used according to the invention a residual moisture content (component b)) of 0.1 to 15% by weight, in particular 0.5 up to 10% by weight and an average mass-related particle size of greater than or equal to 5 µm, especially 5 to 5000 µm, preferably 15 to 2000 µm and in particular from 40 to 1000 µm. The solid brightener preparations to be used according to the invention are based in particular on a spherical or spherical one or particle structure derived therefrom. Agglomerates also come from Particles from the shapes mentioned in the range of the specified particle size in Question. According to the invention, the solid brightener preparations can be powders, granules or so-called microgranules (e.g. from single-component nozzle spray drying).

After drying, the solid preparations can also be used known methods worked up, in particular dusted. The dedusting can be used directly in connection with drying e.g. as injection dedusting or aerosol dedusting as well as following the drying, for example in a mixer or a fluidized bed.

Both water-soluble and water-insoluble or sparingly soluble compounds are suitable as dedusting agents. Such means are known per se; Examples of water-soluble dustproofing agents are polyglycols (PEG) and PEG block copolymers;
White oils and aromatic or aliphatic alkyl esters boiling above 150 ° C. may be mentioned as poorly soluble dedusting agents. Preferred dedusting agents are polyethylene glycol and glycerol mono (di / tri) acetic acid ester.

The use of the solid brightener preparations according to the invention relates to this Lightening paper pulps in papermaking ("bulk dyeing"), e.g. Cellulose, Wood pulp (chemical and mechanical pulp), the lightening of the paper industry commonly used coating slips, i.e. the lightening of unfilled, especially filled paper masses and pigmented coating slips, as well as lightening in the glue or film press.

The use according to the invention is preferably characterized in that the solid brightener preparation either yourself or, if necessary, after mixing with Water into an aqueous pulp mixture, paper coating slip or size press liquor is introduced.

Mixing with water means preferably dissolving.

When used in the pulp, the dissolving process can take place during or during the Are fed into the pulp mixture and / or in the pulp mixture itself, it is preferred that the dissolving process is complete before the paper sheet is formed is completed.

Use in bulk coloring or surface coating is particularly preferred, which is preferably characterized in that the solid brightener preparation continuously or discontinuously, preferably continuously, with a concentration of 0.01 to 40 wt .-%, based. on component a), in particular 1 to 25 wt .-% at a temperature of 10 to 75 ° C, in particular 15 to 55 ° C, and a pH of 6.0 to 12, in particular 6.5 to 11, very particularly 6.5 to 9.5, is dissolved in water and in an aqueous pulp mixture, paper coating slip or size press liquor is introduced.

In the case of mass staining, an aqueous solution of the solid brightener preparation can preferably be used the pulp at each stage of the paper making process before Sheet formation can be added.

Continuous means that the brightener preparation in the Desired concentration, based on the mass of paper pulp, continuously the paper pulp is added; this advantageously takes place in the both the solid brightener preparation and water in a certain ratio for brightener preparation, for example in a stirrer tank, continuously be brought together, the optical brightener is released and the received, generally concentrated, solution to the material flow or the dilution water is metered into the paper machine in the desired ratio.

The invention further relates to the use in coating compositions for optical Lighten paper.

The preferred coating slips contain, for example, plastic dispersions as binders based on copolymers of butadiene-styrene, acrylonitrile-butadiene-styrene, Acrylic acid esters, ethylene vinyl chloride or ethylene vinyl acetate or based on homopolymers, such as polyvinyl chloride, polyvinylidene chloride, Polyethylene, polyvinyl acetate or polyurethanes. A preferred binder consists of styrene-butyl acrylate or styrene-butadiene-acrylic acid copolymers. Further polymer latices are described, for example, in US Pat. No. 3,265,654. Aluminum silicates, such as, are usually used to pigment the coating slips China clay and kaolin, also barium sulfate, satin white, titanium dioxide or natural or precipitated calcium carbonate.

The coating slips preferably contain 5 to 75% by weight of an at least white pigment. The binder is preferably used in an amount sufficient that the dry content of polymeric compound 1 to 30 wt .-%, preferably Accounts for 5 to 25% by weight of the white pigment. The amount of the invention The fixed brightener preparation to be used is preferably calculated in such a way that the brightener of component a) in amounts of 0.005 to 2 wt .-%, in particular 0.01 to 1.5 wt .-%, based on white pigment, is present.

The coating slip can be produced, for example, by the Components in any order at temperatures from 10 to 100 ° C, preferably 20 to 80 ° C, mixes. The components here also include the usual ones Tools used to regulate rheological properties, such as viscosity or water retention that coating slips can be used. Such Tools are e.g. natural binders such as starch, casein, protein or Gelatin, cellulose ethers, such as carboxyalkyl cellulose or hydroxyalkyl cellulose, Alginic acid, alginates, polyethylene oxide or polyethylene oxide alkyl ethers, copolymers of ethylene oxide and propylene oxide, polyvinyl alcohol, polyvinyl pyrrolidone, water-soluble condensation products of formaldehyde with urea or melamine, Polyphosphates or polyacrylic acid salts.

The solid brightener preparations to be used according to the invention are either into the finished coating slip or into one of the components of the coating slip incorporated. The solid preparations can be added directly or likewise be added in the form of aqueous solutions. Aqueous solutions if necessary, produced continuously and in the process of the so-called intermediate step continuously introduced.

The coating slip can, in particular, be used to coat cellulose-based materials Paper, wood, foils, e.g. Cellulose, cellulose triacetate, cotton fabrics etc. can be used. Application to is particularly preferred Paper, cardboard and cardboard as well as photo paper.

The coating slip can be applied to the substrate by any conventional method be, for example with an air knife, a doctor knife, one Brush, roller, squeegee or rod, whereupon the coating e.g. with an infrared dryer, hot air dryer and / or contact dryer at temperatures the substrate surface in the range from 60 to 200 ° C., preferably from 90 up to 130 ° C, until a residual moisture of 3 to 6 wt .-% is dried.

Draw using the solid brightener preparations described above the coatings obtained by an optimal distribution of the optical brightener over the entire surface and a resulting increase of whiteness as well as high light fastness.

The brightener preparations to be used according to the invention continue to stand out by a number of advantages. As solid, concentrated, particulate preparations they are easy to pour, can be metered and, if necessary, they are low-dust or low-dust adjustable.

In water they have a particularly high pH above 6.5 and at a temperature from 10 to 55 ° C, especially cold water from 10-30 ° C a very high and residue-free solubility combined with good wetting, less Lump formation, a high dissolving speed, and a sufficiently long one Stability of the solutions against precipitation at concentrations up to 40 % By weight, in particular up to 25% by weight.

The solid brightener preparations can be used for the surface in the usual Glue and film press fleets are used, in portions or continuously in the form of solid preparations or concentrated preparations made therefrom Solutions are added.

Example 1:

R¹ und R²

für -N(CH₂-CH₂-OH)₂ und

R³

für

bedeutet,
5,6 Gew.-% Restfeuchte (Bestimmung mittels IR-Trocknung bei 110°C, bis zur Gewichtskonstanz)
eingebracht und vollständig gelöst.Preparation of a 10% solution of a solid brightener preparation to be used according to the invention:
90 ml of deionized water were placed in a beaker at room temperature in a laboratory magnetic stirrer and, with vigorous stirring, containing 10 g of a solid brightener preparation obtained by spray drying
94.4% by weight of the sodium salt of the optical brightener of the formula (I), in which

R ¹ and R ²

for -N (CH ₂ -CH ₂ -OH) ₂ and

R ³

For

means
5.6% by weight of residual moisture (determination by means of IR drying at 110 ° C, until constant weight)
introduced and completely solved.

The approximately 10% clear solution obtained had a pH of 8.5 and was above one Stable for more than 2 hours.

1 shows the X-ray diffraction spectrum of the fixed Aulheller preparation used (reflection diffractometer D5000, Siemens AG, with automatic aperture diaphragm). The preparation showed no crystalline portions of the brightener. The E1 / 1 value as a measure of the color strength determined by means of extinction at a wavelength of 350 nm was 546.

Example 2:

R¹ und R²

für -N(CH₂-CH₂-OH)₂ und

R³

für

bedeutet,
0,5 Gew.% Baykanol®SL (Bayer AG, Formaldehyd-Kondensationsprodukt der Komp.c) auf Basis von sulfonierten Ditolylether) und
5,0 Gew.% Restfeuchte (Bestimmung mittels IR-Trocknung bei 110°C, bis zur Gewichtskonstanz)
eingebracht und vollständig gelöst.Preparation of a 10% solution of a further solid brightener preparation to be used according to the invention:
90 ml of deionized water were placed in a beaker at room temperature in a laboratory magnetic stirrer and, with vigorous stirring, containing 10 g of a solid brightener preparation obtained by spray drying
94.5% by weight of the sodium salt of the optical brightener of the formula (I), in which

R ¹ and R ²

for -N (CH ₂ -CH ₂ -OH) ₂ and

R ³

For

means
0.5% by weight Baykanol®SL (Bayer AG, formaldehyde condensation product of Comp. C) based on sulfonated ditolyl ether) and
5.0% by weight of residual moisture (determination by means of IR drying at 110 ° C, until constant weight)
introduced and completely solved.

The approximately 10% clear solution obtained had a pH of 8.6 and was above one Stable for more than 2 hours.

2 shows the X-ray diffraction spectrum of the solid brightener preparation used. The preparation showed no crystalline portions of the brightener.

The E1 / 1 value as a measure of the color strength determined by means of extinction was also 546th

Example 3:

Preparation of a 10% solution of a further one to be used according to the invention fixed brightener preparation:

A laboratory magnetic stirrer was placed in a beaker at room temperature 90 ml of deionized water are introduced and, with vigorous stirring, 10 g of a solid Brightener preparation as in Example 2, but following the spray drying in a mixer with 0.6% by weight based on the solid preparation triacetin (Glycerol triacetate) was dedusted, introduced and completely dissolved.

The approximately 10% clear solution obtained had a pH of 8.2 and was above one Stable for more than an hour.

3 shows the X-ray diffraction spectrum of the solid brightener preparation used. The preparation showed no crystalline portions of the brightener, only portions of electrolyte in the form of halite (NaCl). The E1 / 1 value as a measure of the color strength determined by means of extinction was 535.

Example 4: Use according to the invention in pulp dyeing

200 ml of a 2.5% aqueous pulp mixture containing 30 parts of Nordic long fiber sulfate pulp and 70 parts of Nordic short fiber sulfate pulp were placed in a laboratory sheet former and made up with 800 ml of deionized water. The brightener solutions of Examples 1-3 were then corresponding to the concentrations ¹ shown in Table ¹ the brightener active ingredients are introduced with stirring and after 10 minutes stirring the hand sheet is formed on the sieve; the sheets obtained were then carefully dried on a drying cylinder at a temperature of 95 ° C. and conditioned for a period of 12 hours at 23 ° C. and 50% relative atmospheric humidity. Were assessed the colorimetric values L *, a *, b * (Cielab 1976), the CIE whiteness, the TAPPI whiteness and visual inspection of sheets of white paper.

By comparison, unlightened papers of the same mixture had a CIE whiteness of 74% and a TAPPI whiteness of 87%.

Example 5: Use according to the invention in paper coating

60 Teile Calciumcarbonat

40 Teile Kaolin

10 Teile SBR-Latex

1 Teil Polyvinylalkohol

0,25 Teile Polyacrylsäure

Brightener-free and wood-free A4 base papers (basis weight 80 g / m ² ) were coated on a laboratory doctor device (Erichsen, K-Control-Coater, model K 202) with coating colors of the following composition:

60 parts calcium carbonate

40 parts of kaolin

10 parts of SBR latex

1 part polyvinyl alcohol

0.25 part polyacrylic acid

The pH of the coating color was adjusted to 8-8.5 with dilute sodium hydroxide solution and the solids content of the coating color was adjusted to 60-65% by adding water. The coating color was divided into 3 parts and in each part of the coating color were the solid brightener preparations described in Examples 1 to 3 in a quantity of 5 g based on 1 kg of coating color homogeneously introduced and over solved a period of 10 min.

The sheets coated in this way were dried in a drying cylinder at 95 ° C. for 1 min and then stored for 3 hours at 23 ° C and a humidity of 50%, before they were measured. In all 3 cases papers with a very high result high whiteness and good levelness.

Example 6: (Application in the paper size press)

50 g/l Stärke und

1 g/l feste Aufhellerpräparationen entsprechend den Zusammensetzung aus Beispiel 1 bis 3.

Brightener-free and wood-free DIN A4 base papers (basis weight 80 g / m ² ) were wetted with aqueous liquors on a laboratory size press (Werner Matthis AG, TYPE No. HF 18374)

50 g / l starch and

1 g / l solid brightener preparations corresponding to the composition from Examples 1 to 3.

The pH of the liquors was about 7. The wet pickup was about 50-60%.

The leaves were then dried in a drying cylinder at 95 ° C. for 1 min then stored for 3 hours at 23 ° C and a humidity of 50% before they were measured. In all three cases papers with a very high result high whiteness.

Example 7: Continuous process according to the invention for continuous dissolving and for use in pulp dyeing

The solid brightener preparation described in Example 1 was used over a period of time of 1 hour (stationary operation) continuously using a dosing screw a quantity of 120 kg / h (average over 10 min discharge time at fixed screw speed) using a hold-up disperser together with 880 l / h 45 ° C warm, partially demineralized water in a 500 l stirred tank with propeller stirrer from Initiated above and at the same time 1000 kg / h of the mixture obtained on the bottom removed by means of a rotor-stator pump. The stirrer speed was set so that a high mixing effect was achieved, so that floating of particles of the solid brightener preparation was avoided. In the stationary Condition was the container filling about 300 l, the average residence time of the mixture 0.3 hours in the stirred container. Samples placed at 5 min intervals behind the discharge pump were removed, contained the desired clear solution of the solid Brightener preparation, only in a few individual cases were <2mm large preparation particles discovered, but also within less than 1 min Solution went. Only negligible foaming in the container was observed. The El / 1 values of the samples of the solution were in the range of 64 +/- 3, the stability the solution against precipitation was more than 3 hours (with cooling Room temperature). The concentrated solution thus obtained was therefore excellent Suitable to continuously in the material flow of a paper machine in the desired Ratio (desired concentration of the brightening agent) to be metered.

With the method described, it was also possible to provide sufficiently stable, adjust clear solutions up to a concentration of more than 18% by weight.

With the same procedure, the fixed Auheller preparations could also be made the compositions from Examples 2 and 3 with a comparably good result be resolved continuously. However, the release stability with the fixed Brightener preparation from example 2 more than 6 hours and clear solutions were found up to a concentration of more than 22% by weight can be obtained.

Claims (14)

Use of solid, particulate brightener preparations for optically brightening paper containing a) 85 to 99.9% by weight of at least one optical brightener and b) 0.1 to 15% by weight, in particular 0.5 to 10% by weight, of residual moisture, characterized in that the preparation consists of more than 90% by weight, preferably more than 95% by weight, in particular more than 98% by weight, of components a) and b). Use of solid Aulheller preparations according to claim 1, characterized in that the optical brightener of component a) is selected from the group of stilbene compounds containing sulfo and / or carboxyl groups. Use according to claim 1, characterized in that the optical brightener of component a) is selected from the group of the distilbenes or the triazinylflavonates of the general formula (I)

wherein

R ¹ , R ² and R ³

independently of each other
phenoxy; mono- or disulfonated phenoxy; phenylamino; mono or disulfonated phenylamino; Phenylamino substituted by C ₁ -C ₃ alkyl, cyano, halogen, COOR, CONH-R, NH-COR, SO ₂ NH-R, OR; morpholino; piperidino; pyrrolidino; -OC ₁ -C ₄ alkyl; -NH (C ₁ -C ₄ alkyl); -N (C ₁ -C ₄ alkyl) ₂ ; -NHC ₂ -C ₄ alkylene-OR; -N (C ₂ -C ₄ hydroxyalkyl) ₂ ; -NHC ₂ -C ₄ alkylene-OC ₂ -C ₄ alkylene-OR; an amino acid or an amino acid amide from whose amino group a hydrogen atom has been removed;
-NHCH ₂ CH ₂ OH; -N (CH ₂ CH ₂ OH) ₂ ; -N (CH ₃ ) (CH ₂ CH ₂ OH); -NH ₂ ; -OCH ₃ ; -SC ₁ -C ₄ alkyl; -S-aryl; -Cl; -NH-CH ₂ CH ₂ SO ₃ H; -N (CH ₂ CH ₂ SO ₃ H) ₂ ; or
-N (CH ₂ CH ₂ OH) CH ₂ CH ₂ CONH ₂ mean, and

R

H or C ₁ -C ₃ alkyl and M represents the remainder of an alkali, alkaline earth, ammonium or amine salt.

Use of solid brightener preparations according to claim 1, characterized in that the optical brightener of component a) is selected from the group of the triazinyl flavonates of the formula (I)

wherein

R ¹ , R ² and R ³

independently of each other
-NH ₂ , -NH-CH ₃ , -NH-C ₂ H ₅ , -N (CH ₃ ) ₂ , -N (C ₂ H ₅ ) ₂ , -NH-CH ₂ CH ₂ OH, -NH-C ₂ -C ₄ -hydroxyalkyl, -N (C ₂ -C ₄ -hydroxyalkyl) ₂ , -NH-CH ₂ CH ₂ SO ₃ H; -NH-CH ₂ -CH ₂ -O-CH ₂ -CH ₂ -OH, -OCH ₃ , -OCH (CH ₃ ) ₂ , -O-CH ₂ -CH ₂ -O-CH ₃ , -N (CH ₂ -CH ₂ -OH) ₂ , -N (CH ₂ -CHOH-CH ₃ ) ₂ , morpholino, -SCH ₃ , -N (CH ₂ -CH ₂ -OH) CH ₂ -CH ₂ -CONH ₂ and one of the following leftovers

and M represents the remainder of an alkali, ammonium or amine salt. Use of solid brightener preparations according to claim 3, characterized in that

R ¹ and R ²

for -N (CH ₂ -CH ₂ -OH) ₂ ,

R ³

For

and

M

has the above meaning, in particular stands for Na ⁺ or K +.

Use according to at least one of claims 1 to 5, characterized in that the brightener preparations are powder and have an average mass-related particle size of more than 5 µm. Use according to at least one of claims 1 to 5, characterized in that the brightener preparations are granules or microgranules with an average mass-related particle size of more than 15 µm, in particular more than 40 µm. Use according to at least one of claims 1 to 7, characterized in that the solid brightener preparations are free of crystalline brightener particles, in particular their hydrate forms. Use according to claim 1, characterized in that the solid brightener preparation is dissolved in water and the resulting aqueous solution is introduced into an aqueous cellulose mixture, paper coating slip and / or size press liquor. Use according to at least one of claims 1-8 additionally containing c) 0.1-5% by weight, based on brightener of component a), of at least one condensation product based on A) sulfonated aromatics B) aldehydes and / or ketones and optionally C) one or more compounds from the group of unsulfonated aromatics, urea and urea derivatives. and or
an aromatic or aliphatic alkyl ester boiling above 150 ° C., in particular glycerol mono (di / tri) acetic acid ester. Use according to at least one of claims 1-10 for optical Lighten paper in bulk. Use of solid brightener preparations according to claim 1 for optical Lightening paper in the surface, especially in paper coating colors and glue or film press fleets. Use of solid brightener preparations according to claim 11 for the optical brightening of paper in bulk, characterized in that a solution of the solid brightener preparation in water with a concentration of 0.01 to 40 wt .-%, based. on component a), in particular 1 to 25% by weight at a temperature of 10 to 75 ° C., in particular 15 to 55 ° C., and a pH of 6.0 to 12, in particular 6.5 to 11, very particularly 6.5 to 9.5 produced and added to the paper pulp in each stage of the paper manufacturing process before drying or the paper coating slip or glue or film press liquor. Use of solid brightener preparations according to claim 11 for the optical brightening of paper in bulk, characterized in that the preparation of the solution in water and the addition (dosage) to the pulp is carried out continuously.

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