EP2590759A1

EP2590759A1 - Methods for producing a dispersion containing silicon dioxide particles and cationization agent

Info

Publication number: EP2590759A1
Application number: EP11721515.2A
Authority: EP
Inventors: Stefan Scharfe; Andrea Heuschen; Christoph Batz-Sohn; Burkhard Standke; Christian Wassmer; Heinz Lach
Original assignee: Evonik Degussa GmbH
Current assignee: Evonik Operations GmbH
Priority date: 2010-07-09
Filing date: 2011-05-23
Publication date: 2013-05-15
Also published as: JP2013537568A; US8980960B2; DE102010031184A1; US20130040078A1; TWI467076B; JP5762534B2; WO2012004044A1; TW201217608A; CN102958619A; CN102958619B

Abstract

The invention relates to a method for producing a dispersion containing silicon dioxide particles and cationization agent by dispersing 50 to 75 parts by weight of water, 25 to 50 parts by weight of silicon dioxide particles having a BET surface area of 30 to 500 m²/g, and 100 to 300 μg of cationization agent per square meter of BET surface area of the silicon dioxide particles, wherein the cationization agent can be obtained by reacting at least one haloalkyl-functional alkoxy silane, the hydrolysis products or condensation products thereof, and/or a mixture of the aforementioned substance with at least one amino alcohol and a defined amount of water and optionally removing the formed hydrolysis alcohol at least partially from the reaction mixture. The invention further relates to a method for producing a dispersion containing silicon dioxide particles and cationization agent by dispersing 50 to 75 parts by weight of water, 25 to 50 parts by weight of silicon dioxide particles having a BET surface area of 30 to 500 m²/g, and 100 to 300 μg of a cationization agent per square meter of BET surface area of the silicon dioxide particles, wherein the cationization agent comprises one or more quaternary, amino-alcohol-functional, organosilicon compounds of the general formula III and/or condensation products thereof, where R_u and R_v are, independently of each other, an alkyl group having 2 to 4 carbon atoms, m = 2 to 5, and n = 2 to 5.

Description

Process for the preparation of a silicon dioxide particles and

Cationizing agent-containing dispersion

The invention relates to a process for the preparation of a dispersion comprising silicon dioxide particles and cationizing agents, to the dispersion itself and to a coating paint obtainable therewith.

It is known that silica-containing aqueous dispersions for

Production of coating colors for ink-receptive layers in the inkjet area to use. To improve the quality, especially the

Waterfastness and color density of the resulting ink receiving layers are disclosed in EP-A-1013605, DE-A-10033054 or US Pat

EP-A-1331254 added cationic polymers. Especially with highly filled dispersions, the better because the recipes of the resulting

Coating colors and economic and environmental reasons (reduced evaporation of water and energy expenditure during drying) are particularly desirable, but the addition of known cationic

Polymers lead to an extreme increase in viscosity and a

Make processing of the dispersions impossible at high degree of filling.

EP-A-1413451 discloses a process for producing a media sheet for ink-jet printing applications in which porous, inorganic macroparticles and an organosilane reagent are reacted on a substrate. The inorganic macroparticles may be silica particles. The organosilane reagent is an oligomer of the structure

wherein x + y = 4, R ¹ and R ^{2 are} aminopropyl and the molecular weight is 270 to 550. With this method, the durability of the printing inks can be improved.

Despite the advances in the art, the processability of the high solids dispersions used and the improvement of inkjet print quality remain key parameters to be improved.

It was therefore the technical object of the present invention

To provide dispersion which does not have the deficiencies of the prior art. Another object was to provide an improved high solids coating paint from this dispersion.

The invention relates to a process for the preparation of a

Silica particles and cationizing agent-containing dispersion, characterized in that

a) 50 to 75 parts by weight of water

b) 25 to 50 parts by weight of silica particles having a BET surface area of 30 to 500 m ² / g and

c) 100 to 300 g of cationizing agent per square meter BET surface of the silica particles

dispersed, wherein

the cationizing agent is obtainable by reacting at least one haloalkyl-functional alkoxysilane, its hydrolysis products or condensation products and / or a mixture of the abovementioned substances with at least one aminoalcohol and a defined amount of water and optionally optionally at least partially removing the hydrolysis alcohol formed from the reaction mixture, the haloalkyl-functional alkoxysilane the general formula I

(R ¹ O) _3- x _-y (R ² ) x Si [(R ³ ) n CH 2 Hal] i _{+ y} (I), in which

Groups R ^{1 are} identical or different and R ^{1 is} a hydrogen, a linear, branched or cyclic alkyl group having 1 to 8 C atoms, an aryl, arylalkyl or acyl group, R ^{2 are the} same or different and R ^{2 is} a linear, branched or cyclic alkyl group having 1 to 8 C atoms or an aryl, arylalkyl or acyl group,

R ^{3 are the} same or different and R ^{3 is} a linear, branched or cyclic alkylene group having 1 to 18 C atoms,

n is 0 or 1 and Hal is chlorine or bromine,

and x is 0, 1 or 2, y is 0, 1 or 2 and (x + y) is 0, 1 or 2,

the aminoalcohol the general formula II

[HO- (CH ₂ ) _m -] z N (R ⁴ ) _3- z (II), in which

Groups R ^{4 are the} same or different and R ^{4 is} a group

comprising C1 to C16 atoms, m is an integer between 1 and 16 and z is 1 or 2 or 3.

In the further embodiments of the invention, the haloalkyl-functional alkoxysilane, its hydrolysis products or condensation products and / or a mixture of the abovementioned substances is to be referred to as component A and the aminoalcohol as component B.

The reaction of component A and component B is carried out in

Presence of a defined amount of water or reacting component A with component B and subsequently hydrolyzing in the presence of a defined amount of water, preferably component A,

in particular of the formula IR ¹ is alkyl having 1 to 4 C atoms, acyl, and R ^{3 is} a linear alkylene group having 1, 2, 3, 4, 5, 6, 7 carbon atoms, preferably having 2 C atoms. Preferred usable haloalkyl-functional alkoxysilanes

3-Chloro-propyltrimethoxysilane, 3-chloropropyltriethoxysilane,

3-chloropropyltripropoxysilane, chloropropylmethyldimethoxysilane,

Chloropropylmethyldiethoxysilane, chloropropyldimethylethoxysilane,

Chloropropyldimethylmethoxysilane, chloroethyltrimethoxysilane,

Chloroethyltriethoxysilane, chloroethylmethyldimethoxysilane,

Chloroethylmethyldiethoxysilane, chloroethyldimethylmethoxysilane, Chloroethyldimethylethoxysilane, chloromethyltriethoxysilane,

Chloromethyltrimethoxysilane, chloromethylnethyldinnethoxysilane,

Chloromethylmethyldiethoxysilane, chloromethyldinnethylnethoxysilane,

Chloromethyldinnethylethoxysilane, 2-chloroisopropyltris (nethethoxyethoxy) silane, 3-chloropropylcyclohexyldiethoxysilane, 3-chloroisobutyltrinnethoxysilane,

3-chloroisobutyltriethoxysilane, 3-chloropropylcyclohexyldimethoxysilane,

3-bromoisopropyldiethylcyclohexoxysilane, 3-chloropropylcyclopentyldienethoxysilane,

3-bromoisobutyltrinnethoxysilane, 3-chloroisobutylbis (ethoxyethoxy) n-methylsilane,

4-bromo-n-butyltriethoxysilane, 4-chloro-n-butyldiethoxycyclopentylsilane,

5-bromo-n-pentyltriethoxysilane, 5-bromo-n-pentyltri-n-butoxysilane,

4-bromo-3-methylbutyldinnethoxyphenylsilane, 5-bromo-n-pentyltri-n-butoxysilane,

5-chloro-n-pentyltriethoxysilane, 6-chloro-n-hexylethoxydimethylsilane,

6-bromo-n-hexylpropyldipropoxysilane, 6-chloro-n-hexyldiethoxyethylsilane,

7-chloro-n-heptyltriethoxysilane, 7-chloroheptyldimethoxycycloheptylsilane,

7-bromo-n-heptyl-diethoxycyclooctylsilane, 8-chloro-n-oxy-triethoxysilane,

8-bromo-n-octyldimethylcyclohexoxysilane, 3-chloropropyldiethoxyphenylsilane, 3-chloropropylmethoxyethoxybenzylsilane, 3-bromopropyldinnethoxybenzylsilane and / or their hydrolysis and / or homo- and / or co-condensation products or advantageously 1,4-chlorophenyltrimethoxysilane,

1, 4-chlorobenzyltriethoxysilane and chloromethyl-p-methylphenyl-trimethoxysilane and / or their hydrolysis and / or homo- and / or co-condensation products.

Particular preference may be given to 3-chloropropyltrimethoxysilane,

3-chloropropyltriethoxysilane, 3-chloropropylmethyldimethoxysilane,

3-chloropropylmethyldiethoxysilane, 3-chloropropyldimethylethoxysilane or 3-chloropropyldimethylmethoxysilane or a hydrolysis or

Condensation product of the aforementioned alkoxysilanes are used.

It is particularly advantageous to use components A and B with respect to the haloalkyl group of component A and the tertiary nitrogen of component B in a molar ratio of 2: 1 to 1: 100, in particular from 2: 1 to 1:10, preferably from 2: 1 to 1: 5, more preferably from about 1: 1 to about 1: 1, 5, wherein, if appropriate, initially setting a ratio of 1: 1 and subsequently each batch of about 0.2 of component B with respect to the present component A in 1 to 4 batches.

A process procedure has proven particularly advantageous in which water is present in an amount of from 0.5 to 500 mol of water per mole

Silicon atoms of component A is used, preferably in at least one of the hydrolysis steps 0.5 mol of water per mole of hydrolyzable alkoxy group on the silane, wherein total preferably in particular 0.5 to 25 moles of water, preferably 5 to 25 moles of water per mole Silicon atoms with respect to

used component A, more preferably 10 to 25 moles of water per mole of silicon atoms, in particular 12 to 25 moles of water per mole of silicon atoms are used.

Depending on the process, it has proved to be advantageous if the reaction is carried out in the presence of a solvent, in particular alcohol, preferably in the presence of the resulting alcohol in the hydrolysis of the alkoxysilanes, particularly preferably in the presence of ethanol, methanol,

n-propanol or iso-propanol. In this case, the added solvent is suitably removed during the removal of the hydrolysis alcohol formed during the reaction from the system. The educated in the implementation

Hydrolysis alcohol is substantially completely removed, preferably by distillation, in particular already during the reaction. According to a particularly preferred procedure, for example, the amount of hydrolysis alcohol removed by distillation and water in the azeotropic mixture can be compensated for by additional addition of water. Volatile solvents, such as an added solvent and / or the alcohol formed in the reaction by hydrolysis, ie groups which are optionally hydrolysable to volatile solvent, in particular hydrolysis alcohol, are removed to a content in the total composition of less than 12 wt.% To 0 wt. -%, preferably by distillation according to the skilled worker methods. A solvent is considered to be a composition if the content of solvents in the overall composition is less than 10 % By weight to 0% by weight, more preferably less than 5% by weight, very particularly preferably less than 2% by weight to 0.0001% by weight, in particular 1 to <0.5% by weight, preferably 0.5 to <0.1 wt .-% could be adjusted, wherein the removal of volatile solvent during the reaction and / or thereafter by distillation, in particular under reduced pressure in the range of 1 to 1000 mbar, preferably from 80 to 300 mbar, more preferably in the range of 80 to 180 mbar, can take place. Suitably, however, one can also lower the pressure in the course of the conversion of ambient pressure to a reduced pressure. The distillation can be carried out batchwise or else continuously by means of a distillation column, thin-film evaporator and further the

Professional common apparatuses. In the distillation is

preferably distilled until at the top of the separation column only water is detectable. Distilled water can be supplemented by re-addition of water. At the end of the distillation can be the desired

Final concentration of the solution can be adjusted by adding more water.

The reaction is preferably carried out at a pressure of 1 mbar to 100 bar, preferably by about 1 mbar to 1, 1 bar, preferably at ambient pressure (atmospheric pressure), and a temperature of 20 and 150 ° C, preferably between 40 to 120 ° C, more preferably between 60 to 100 ° C, in particular from 80 to 95 ° C from.

It may be useful to have a hydrolysis and / or

To add condensation catalyst, for example, an organic or inorganic acid such as formic acid, acetic acid, propionic acid,

Citric acid, hydrogen chloride, as gas, concentrated or aqueous

Hydrochloric acid, boric acid, nitric acid, sulfuric acid or phosphoric acid.

Accordingly, an inorganic or organic acid can also be added at any time to adjust the pH of the composition or reaction mixture. Further, it may be preferable to use metal oxides, preferably

Metal oxides with condensable hydroxy groups. these are

in particular silica, fumed silica, precipitated silica, silicates, boric acid, titanium dioxide, alumina, alumina hydrate, ATH

(Aluminum trihydroxide, Al (OH) ₃ ), magnesium hydroxide (Mg (OH) ₂ ), cerium oxide, yttrium oxide, calcium oxide, iron oxides, zirconium oxide, hafnium oxide, boron oxide, gallium oxide, indium oxide, tin oxide, germanium oxide and corresponding hydroxides and oxide hydrates and mixtures of at least two the aforementioned compounds with each other. Suitable volatile solvents or groups which can be hydrolyzed to volatile solvents are alcohols, such as methanol, ethanol, isopropanol, n-propanol, and alkoxy groups which hydrolyze to alcohols, acyloxy group-containing radicals, and acetic acid or formic acid derived by hydrolysis, or aryloxy groups which can form phenols and also glycols and partially etherified glycols, such as ethylene glycol, diethylene glycol or methoxyethanol, which are either added to the formulation or formed by hydrolysis of their silyl esters conceived.

The invention further relates to a process for the preparation of a special silica particles and cationizing agent-containing dispersion, wherein

a) 50 to 75 parts by weight of water

c) 100 to 300 g of one or more quaternary, amino-functional,

organosilicon compounds per square meter BET surface area of

silica

dispersed,

wherein the cationizing agent comprises one or more quaternary,

aminoalcohol-functional, organosilicon compounds of the general formula III and / or their condensation products, wherein R _u and R _{v are} each independently an alkyl group of 2 to 4 carbon atoms, m is 2 to 5 and n is 2 to 5.

Particularly preferred is an embodiment in which u = v = Me, m = 3 and n = 2.

The condensation products of the quaternary, aminoalcohol-functional, organosilicon compounds can have linear, branched and / or cyclic structures or structural regions with M, D, T structures. According to ²⁹ Si NMR spectroscopy these are, in addition to preferably 0.5 to 5%, particularly preferably 1 to 3%, monomeric structures, preferably 3 to 15%, particularly preferably 5 to 10%, M structures and preferably 35 to 60th %, more preferably 40 to 55%, of D structures. A definition of M-D, T structures can be found in Walter Noll, Chemie und Technologie der Silicones, 1968, Verlag Chemie GmbH, Weinheim, Chapter 1. Furthermore, the quaternary, aminoalcohol-functional, organosilicon compounds preferably have a number average molecular weight M _n of 500 to 5000, particularly preferably 1000 to 2500 on.

The proportion of quaternary, aminoalcohol-functional, organosilicon compounds in the aqueous solution is preferably 30 to 60 wt .-% and particularly preferably 40 to 50 wt .-%.

silica

The silica particles used are amorphous silica particles. The silica particles carry condensable groups on their surface, for example OH groups. To include also Mixed oxides with silica as a component or coated with silica metal oxide particles. The amorphous silica particles can

For example, by means of electric arc method, plasma method, wet-chemical method, such as precipitation and gelling methods, and be prepared by pyrogenic methods. Preferably, the silica particles are pyrogenically produced particles. By pyrogenic is meant the hydrolysis or oxidation of silicon compounds in the gas phase in a flame generated, as a rule, by the reaction of hydrogen and oxygen. Firstly, highly dispersed, non-porous primary particles are formed, which grow together in the further course of the reaction to form aggregates and which can further assemble them into agglomerates.

The BET surface area of the silica particles used can vary over a wide range, from 30 to 500 m ² / g. However, it has been found that the use of pyrogenically prepared silicon dioxide particles having a BET surface area of 200 m ² / g or more, in particular those having a BET surface area of 240 to 330 m ² / g, leads to dispersions which have particularly good properties in the Inkjet area have.

Other starting materials for the preparation of the dispersion

In the method according to the invention, one or more basic substances can additionally be used. As a rule, these may be amines and / or salts thereof. In order to further improve the stability of the dispersion according to the invention, acids can be used. Suitable acids may be hydrochloric acid, C 1 -C 4 -carboxylic acids, C 1 -C 4 -hydroxycarboxylic acids or C 1 -C 4 -dicarboxylic acids. The acid is usually added in an amount such that a pH of the dispersion of 2 to 6, preferably 3 to 5, more preferably 3.5 to 4.5 results. It should be noted, however, that even without the addition of acid stable dispersions can be obtained. Furthermore, organic solvents, bactericides and / or fungicides can be used in the preparation of the dispersion. In general, in the preparation of the dispersion, the procedure is that initially under low energy input, for example by means of a

Dissolvers, a predispersion prepared by adding silica particles to the liquid components of the dispersion. In a second step, the actual dispersion takes place, in which the energy input is higher than in the first step. Suitable Dispregieraggregate are known in the art. An example is a rotor-stator unit called.

Another object of the invention is a dispersion obtainable by the process according to the invention. This has an average particle diameter, determined by means of dynamic light scattering, of preferably 120 to 250 nm, particularly preferably 130 to 180 nm.

In a preferred embodiment, the dispersion according to the invention contains 35 to 40% by weight of pyrogenically prepared silicon dioxide particles having a BET surface area of 250 m ² / g to 350 m ² / g and the average particle diameter determined by dynamic light scattering is 130 to 180 nm ,

coating color

Another object of the invention is a coating color which contains the dispersion according to the invention and at least one binder.

Examples of binders which can be used are: polyvinyl alcohol, partially or completely saponified, and cationized polyvinyl alcohol having a primary, secondary or tertiary amino group or a tertiary one

Ammonium group on the main chain or on the side chain. Further

Combinations of these polyvinyl alcohols with each other and

Polyvinylpyrrolidones, polyvinyl acetates, silanized polyvinyl alcohols, styrene-acrylate latices, styrene-butadiene latices, melamine resins, ethylene-vinyl acetate copolymers, polyurethane resins, synthetic resins such as polymethyl methacrylates, polyester resins (eg unsaturated polyester resins), polyacrylates , modified starch, casein, gelatin and / or cellulose derivatives (eg

Carboxymethyl cellulose). Preference is given to using polyvinyl alcohol or cationized polyvinyl alcohol. Furthermore, the coating color may also contain one or more other pigments such as calcium carbonates, layered silicates, aluminum silicates, plastic pigments (eg polystyrene, polyethylene, polypropylene), silica gels, aluminum compounds (eg aluminum sols, colloidal aluminas and their hydroxy compounds such as pseudoboehmites, boehmites, aluminum hydroxides). .

Magnesium oxide, zinc oxide, zirconium oxide, magnesium carbonates, kaolin, clay, talc, calcium sulfate, zinc carbonate, satin white, lithopone, zeolites.

The coating color may have a content of mixed oxide particles between 10 and 60 wt .-%. It may preferably be greater than 15% by weight, more preferably it may be greater than 25% by weight.

To increase the water resistance of the binder system and thus the

Coating may serve crosslinkers such as zirconium oxides, boric acid,

Melamine resins, glyoxal and isocyanates and other molecules containing the

Connect molecular chains of the binder system. Furthermore, auxiliaries such as optical brighteners, defoamers,

Wetting agents, pH buffers, UV absorbers and viscosity aids are used.

The coating composition according to the invention preferably has a solids content of from 10 to 30% by weight and more preferably from 15 to 30% by weight. Another object of the invention is the use of the

Dispersion according to the invention and coating color for coating ink-receiving inkjet media.

A further subject of the invention is an ink-receiving medium comprising an ink-receiving layer, wherein the ink-receiving layer comprises the coating color of the invention and a support. As the support, there can be used, for example, paper, coated paper, resin films such as a polyester resin including polyethylene terephthalate, polyethylene naphthalate

Diacetate resin, a triacetate resin, an acrylic resin, a polycarbonate resin, a Polyvinyl chloride, a polyimide resin, Celluphan, celluloid and a glass plate can be used.

Preferred are so-called photo base papers, i. Papers on which one or more layers of polyethylene film has been applied to the front and / or back. Furthermore, polyester film, PVC film or

pre-coated papers.

The ink-accepting medium of the present invention also includes media in which the ink-receiving layer consists of multiple coating layers of the same type or other layers. The coating color according to the invention can only be in one or more layers. For example, further ink-absorptive coatings may be included. Further, one or more polymeric layers (e.g., polyethylene) may be applied to the substrate and / or the coating of the present invention to increase mechanical stability and / or gloss in the coating (e.g., photo base paper, lamination).

The carriers can be transparent or opaque. The thickness of the carrier is not limited, preferably thicknesses between 50 and 250 μιτι be used.

To prepare the ink-receiving medium, the coating color can be applied to the support and dried. The application of the

Coating paint can be used with all common application methods, such as roller application, blade coating, air brush, doctor blade (profiled, smooth, nip), cast-bar process, film press, size press, curtain-coating process and slot nozzle application (eg casting squeegee, slot-dye) and

Combinations are applied from this. Preference is given to using processes which permit a very homogeneous coating, such as, for example, casting, curtain coating and slot die application. The coated substrate can with all conventional methods such as air or convection drying (eg hot air duct), contact or

Conduction drying, energy beam drying (e.g., infrared and

Microwaves) are dried.

Examples:

Determination Methods:

Hydrolyzable chloride was titrated potentiographically with silver nitrate (for example, Metrohm, Type 682 silver rod as indicator electrode and Ag / AgCl reference electrode or other suitable reference electrode).

Total chloride content after Wurtzschmitt digestion. For this purpose, the sample is digested in a Wurtzschmittbombe with sodium peroxide. To

Acidification with nitric acid is measured potentiographically with silver nitrate, as above. In the case of a complete conversion of the chloroalkyl function with tertiary amines, the analysis values for hydrolyzable chloride and total chloride are identical and thus a measure of the completeness of the reaction, since with total chloride the sum of salt-like chloride (amine hydrochloride) and covalently bonded chlorine (chloroalkyl function) and with hydrolyzable chloride exclusively salt-like or water-cleavable chloride

(in the present case, amine hydrochloride) is determined. At the beginning of the reaction, the hydrolyzable chloride value is zero and at full conversion increases to the value measured for total chloride. Therefore, these analyzes are excellent in addition to ¹ H and ¹³ C NMR spectroscopy as a reaction control.

The alcohol content after hydrolysis is determined by gas chromatography. For this purpose, a sample of a defined amount is hydrolyzed with sulfuric acid (5 g sample, 25 ml H ₂ SO ₄ , w = 20%). 75 ml of distilled water are added. Then neutralized with sodium hydroxide solution and a

Steam distillation performed. Internal standard 2-butanol. The determination of nitrogen, organically bound, ammonium, etc. organically bound nitrogen can be converted into ammonium by means of Kjeldahl digestion and determined by addition of sodium hydroxide solution as ammonia acidimetrisch. Procedure: Heat up to 5 g sample with 10 ml sulfuric acid (conc.) And a Kjeldahl tablet (Merck 1 .15348) until the

Digestion solution bright and clear of any precipitated silica is clear. The digestion vessel is connected to the distillation apparatus and distilled over ammonia released ammonia (27%) in the template. The ammonia content is titrated with addition of boric acid (2%) with sulfuric acid (c (H ₂ SO ₄ ) = 0.05 mol / l or 0.005 mol / l). V = consumption of sulfuric acid in ml, c = concentration of sulfuric acid in mol / l, z =

Equivalent number of sulfuric acid = 2, E = weight in mg

Evaluation: N [%] = (100 * V * c * z * 14.01) / E

The determination of S1O2 is carried out after decomposition by means of sulfuric acid and Kjeldahl catalyst, by determining the weight of the precipitated S1O2. Procedure: The 1 g sample is spiked in a 250 ml beaker with a Kjeldahl tablet (e.g., Merck # 15348) and 20 mL sulfuric acid (conc.). The solution is heated slowly. The organic components are oxidized until the digestion solution remains clear and bright when the sulfuric acid is being smoked. After cooling and careful dilution to about 200 ml, the precipitated silica is filtered off through a white-band filter. The filter is washed with water until the pH of the wash water is> 4, then dried in platinum crucible and ashed. The residue is calcined at 800 ° C and weighed. After fuming with hydrofluoric acid (conc.) Is annealed again at 800 ° C and weighed, m = weight difference before and after fl uorination in g; E = weight in g

Evaluation: SiO ₂ [%] = 100 ^■ m / E In the following, the DIN standards used to determine the mentioned parameters are reproduced: Solids content according to DIN 38409-1 (1987-01-00), refractive index according to DIN 51423 (2010-02-00), density according to DIN

51757 (1994-04-00), viscosity according to DIN 53015 (2001 -02-00), color number according to DIN EN ISO 6271 (2005-03-00) and haze according to DIN EN ISO 7027 (2000-04-00).

Example 1: Preparation of a cationizing agent

Chloropropyltriethoxysilane (CPTEO) and N, N-Dimethylethanolamine A 41 four-necked flask is charged with 1283.0 g of CPTEO (5.328 mol) and 160.0 g of ethanol. At RT, 143.9g of deionized water (1.5mol H2O / mol of Si) are removed within 16min. dropwise. The bottom temperature rises to about 40 ° C.

Subsequently, 570.5 g (6.400 mol) of dimethylethanolamine within 6 min. been touched. The bottom temperature rises from 40 ° C to about 48 ° C. Subsequently, about 45min. boiled at reflux (bottom temperature about 85 ° C).

At atmospheric pressure 1706.6 g of water / ethanol / dimethylethanolamine is distilled off within about 6 hours. During this time will be in seven

Portions 2038.3 g of water. After about 3 h of distillation 432.4 g of demineralized water were introduced in 3 portions. The swamp sample now shows a good solubility in demineralised water.

Within 1, 7 h at a bottom temperature of 50 ° C to 55 ° C and an absolute pressure of about 140 mbar 529.4 g of water / ethanol /

Dimethylethanoldiamin distilled off mixture. At the end of the distillation 560.17 g of demineralized water are added. Obtained is a slightly cloudy / slightly yellowish low-viscosity liquid. Yield: 2521, 7 g

The physico-chemical data of the cationizing agent from Example 1 are given in Table 1. ¹ H and ¹³ C-NMR: purity of the target compound about 95.8mol%. 4.2 mol% of free dimethylethanolamine. No evidence of transesterification of

Aminoethanolgruppe to SiOR.

²⁹ Si NMR: 1% Si silane, 7% Si M structures, 45% Si D structures, 47% Si T structures

Examples 2: Preparation of Dispersions D1 to D3

The following dispersion examples D1-D3 were developed with the proviso that the dispersions have a low viscosity and similar

Performance in paper coating in terms of pore structure and

Have pore volume. As a measure of the porosity of the coating, the average aggregate size in the dispersion, measured with dynamic light scattering, has been found. Within a system, higher fill levels during dispersion result in a decrease in mean particle size. The examples show that through the use of the invention

Silansystems very high fill levels while maintaining the

desired aggregate size can be realized.

D1: Dispersion from AEROSIL ^® 300 silica and poly-diallyl dimethyl ammonium chloride (p-DADMAC) (Comparative Example)

60g of p-DADMAC are added to 1350g of DI water. Then, 320 g of AEROSIL ^® 300 are by means of a dissolver at 1500 to 4000 rev / min for 40 min and then stirred further predispersed over a period of 5 min at 2000 U / min. Subsequently, with a rotor-stator dispersion at 15000 rev / min with cooling (<30 ° C) is dispersed for 30 minutes. Finally, the dispersion is filtered through a 500 μιτι sieve.

D2: Dispersion from AEROSIL ^® 300 silica and N- butylaminopropyl-trimethoxysilane (Dynasylan ^® 1 189) (Comparative Example)

To 1200 g of deionized water 425 g of AEROSIL ^® 300 are by means of a dissolver at 1500 to 4000 rev / min for 30 min and then stirred predispersed over a period of five minutes at 2000 rev / min on. Subsequently, it is now dispersed with a rotor-stator disperser at 15,000 rpm with cooling (<30 ° C) for 10 min.

Now, again with the dissolver at 2000 U / min and it is carried out the addition of a mixture of 21, 3 g of Dynasylan ^® 1 189, 67 g of methanol and 20 g of formic acid (50 percent solution in water) within 5 min, then is still 60 minutes in the rotor-stator system at 5000 rev / min at 60 ° C finely dispersed and allowed to react. Finally, the dispersion is cooled and filtered through a 500 μιτι sieve.

D3: dispersion starting from AEROSIL ^® 300 silica and the

Cationizing agent from Example 1 (according to the invention)

428 g of AEROSIL ^® 300 are with a dissolver at 1500 to 5000 U / min in a mixture of 805 g of demineralized water and 47.4 g of the solution of Example 1 within 17 min and stirred for 10 minutes at 2000 rev / min

further dispersed. The mixture is then dispersed with a rotor-stator disperser (Kinematica Polytron PT6100) over a period of 30 minutes at 10,000 rpm. Finally, the dispersion is filtered through a 500 μιτι sieve.

The physico-chemical data of the dispersions D1 -D3 can be found in Table 2.

Examples 3: Preparation of Dispersions D4 - D6

The dispersion examples D4-D6 show, regardless of the parameter of the particle diameter, which solids content is possible with the maximum cationizing additive. As expected, the dispersions have very high viscosities but are still liquid and processable.

D4: Dispersion from AEROSIL ^® 300 silica and poly-diallyl dimethyl ammonium chloride (p-DADMAC) (Comparative Example)

60g of p-DADMAC are added to 1 190 g of deionized water. Then, 320 g of AEROSIL ^® 300 are stirred by means of a dissolver at 1500 to 4000 rev / min and then further predispersed over a period of five minutes at 2000 U / min. The following will now be with a rotor-stator disperser dispersed at 15,000 rpm with cooling (<30 ° C) for ten minutes. Finally, the dispersion is filtered through a 500 μηη sieve.

D5: Dispersion from AEROSIL ^® 300 silica and N- t-butylaminopropyl trimethoxysilane (Dynasylan ^® 1 189) (Comparative Example) There are 1035 g of water and 21 2g Dynasilan ^® 1 189 was stirred into the water. After 30 min. Hydrolysis time, the initial solution is adjusted to pH 4.2 with 63.7 g of acetic acid (25 weight percent solution in water). Now 423,9g AEROSIL ^® 300 are stirred by means of a dissolver at 1500 to 4000 rev / min and then pre-dispersed over a period of five minutes at 2000 rev / min on. Below is now with a rotor-stator dispersion at 10000 U / min with cooling (<30 ° C) 30 minutes

enddispergiert. Finally, the dispersion is filtered through a 500 μιτι sieve.

D6: Dispersion from AEROSIL ^® 300 silica and solution of Example 1 (according to invention)

557 g of AEROSIL ^® 300 are stirred with a dissolver at 1500 to 5000 U / min in a mixture of 885 g of demineralized water and 58 g of the solution from Example 1 and 10 minutes further dispersed at 2000 U / min. It is then dispersed with a rotor-stator disperser (Kinematica Polytron PT6100) over a period of 30 minutes at 10,000 rpm. Finally, the dispersion is filtered through a 500 μιτι sieve.

The physico-chemical data of the dispersions D4-D6 can be found in Table 3.

Examples 4: Preparation of Dispersions D7 - D10

In addition to AEROSIL ^® 300 (BET surface area about 300 m ² / g) can

dispersions of the invention are also prepared based on other AEROSIL® types. For this purpose, the AEROSIL ^® powder is stirred with a dissolver at 1500 to 5000 U / min in a mixture of 885 g of DI water and the appropriate amount of cationizing agent from Example 1 and further dispersed at 2000 U / min for 10 minutes. It is then treated with a rotor-stator dispersing device (Kinematica Polytron PT6100) via a Period of 30 minutes at 10,000 rpm dispersed. Finally, the dispersion is filtered through a 500 μηη sieve. Starting materials and quantities, as well as physical-chemical data of the dispersions D7-D10 are shown in Table 4.

Examples: Production of the coating colors S1 -S3

S1_ To the dispersion D1 is in each case by means of a dissolver at 500 U / min, a 12 weight percent solution of polyvinyl alcohol PVA 235, Messrs. Kuraray Europe, and stirred for 10 minutes. Add as much PVA 235 that the ratio of silica to PVA (dry) is 4: 1 (or 5: 1 for S2 and S3). To adjust the viscosity, sufficient water is added to adjust the solids content indicated in the table. Subsequently, a 7 weight percent solution of boric acid in water is added. The amount of boric acid is 12.5% by weight of the amount of the polyvinyl alcohol.

Finally, the glyoxal-containing composition "Cartabond TSI" from Clariant is added, the amount corresponding to 4.8% by weight of the amount of the polyvinyl alcohol.

The viscosity of the ink jet coating is measured after 24 h by means of a Brookfield viscometer.

S2 and S3 are prepared analogously to S1, but using the respective dispersion D2 and D3. The solids contents and viscosities of the coating colors are shown in Table 5.

Examples: Production of ink-jet coatings

The coating colors S1 to S3 are each profiled using a

Doctor blade applied to a photographic base paper (thickness 300 μιτι). The

Wet film thickness of the respective coating color is chosen so that a

comparable application weight is achieved.

The coating is kept at 105 ° C for a period of 8 minutes

dried. It is achieved a uniform application weight of 22 g / m ² . The coated papers are printed on a Canon PIXMA iP6600D ink jet printer with the highest resolution. The rating of

Printing results are shown in Table 6. The advantages of the coating composition according to the invention lie in a processability which is improved over the prior art, a reduced environmental impact due to lacking VOC components and a faster spreadability due to the lower water content. There are no disadvantages in terms of image intensity and image quality to be accepted.

Table 1: Physicochemical data of the cationizing agent from Example 1

Table 2: Physico-chemical data of the dispersions D1 -D3

Table 3: Physico-chemical data of the dispersions D4-D6

Comparison according to the invention

D4 D5 D6

Solids content ^a) Weight% 23.0 30 39 Avg. Particle 0 ^b) nm 132 125 1 14

Viscosity ^c) mPas 5600 2800 5380 Table 4: Starting materials, physical-chemical data of the dispersions D7-D10

a) after drying to constant weight at 125 ° C; b) middle

Particle diameter after dynamic light scattering (Horiba LB-500);

c) at 1000 s ^-1 , 23 ° C;

Table 5: Solids contents, viscosities of the coating colors S1 -S3

d) viscosity (Brookfield d) at 100 rpm and 20 ° C; measured after 24 h

Table 6: Evaluation ⁸ 'of the print results

e) Best grade 1, worst grade 6; f) bleeding;

g) at 60 ° viewing angle

Claims

claims:

1 . Process for the preparation of a silicon dioxide particles and

Cationizing agent-containing dispersion,

characterized in that one

50 to 75 parts by weight of water, 25 to 50 parts by weight

Silica particles having a BET surface area of 30 to 500 m ² / g and 100 to 300 g of cationizing agent per square meter BET surface of the silica particles dispersed, wherein

the cationizing agent is obtainable by adding at least one

haloalkyl-functional alkoxysilane, its hydrolysis products or

Condensation products and / or a mixture of the aforementioned substances with at least one amino alcohol and a defined amount of water and reacts the resulting hydrolysis alcohol optionally at least partially removed from the reaction mixture, wherein

the haloalkyl-functional alkoxysilane has the general formula I

(R ¹ O) _3- x _-y (R ² ) x Si [(R ³ ) n CH 2 Hal] i _{+ y} (I), in which

Groups R ^{1 are} identical or different and R ^{1 is} a hydrogen, a linear, branched or cyclic alkyl group having 1 to 8 carbon atoms, a

Aryl, arylalkyl or acyl group,

R ^{2 are} identical or different and R ^{2 is} a linear, branched or cyclic alkyl group having 1 to 8 C atoms or an aryl,

Arylalkyl or acyl group,

n is 0 or 1 and Hal is chloro or bromo, and

x is 0, 1 or 2, y is 0, 1 or 2 and (x + y) are 0, 1 or 2, the aminoalcohol is the general formula II

[HO- (CH ₂ ) _m -] z N (R ⁴ ) _3- z (II), in which

Groups R ^{4 are the} same or different and R ^{4 is} a group comprising C 1 to C 16 atoms, m is an integer between 1 and 16 and z is 1 or 2 or 3.

2. The method according to claim 1,

characterized in that

haloalkyl-functional alkoxysilane is chloropropyltriethoxysilane and the aminoalcohol is selected from the group consisting of N, N-dimethylethanolamine, Ν, Ν-diethylethanolamine, N-methyldiethanolamine, N-ethyldiethanolamine and triethanolamine.

3. Process for producing a silica particle and

Cationizing agent-containing dispersion,

characterized in that one

a) 50 to 75 parts by weight of water

c) 100 to 300 g of a cationizing agent per square meter BET surface area of the silica particles

dispersed,

wherein the cationizing agent comprises one or more quaternary,

aminoalcohol-functional, organosilicon compounds of the general formula III and / or their condensation products, wherein

R _u and R _{v are} each independently an alkyl group of 2 to 4 carbon atoms, m is 2 to 5 and n is 2 to 5.

4. The method according to claim 3,

characterized in that

the quaternary, aminoalcohol-functional, organosilicon

Compounds having a number average molecular weight M _n of 500 to 5000.

5. The method according to claim 3 or 4,

characterized in that

an aqueous solution with a concentration of the quaternary,

aminoalcohol-functional, organosilicon compounds of 20 to 60 wt .-% is used.

6. Process according to claims 1 to 5,

characterized in that

pyrogenic silicon dioxide particles are used.

7. The method according to claim 6,

characterized in that

the pyrogenically produced silica particles have a BET surface area of 200 m ² / g or more.

8. Process according to claims 1 to 7,

characterized in that

the dispersion is carried out in the presence of one or more basic or acidic substances or salts thereof.

9. Process according to claims 1 to 8,

characterized in that

the dispersion takes place by means of a rotor-stator assembly.

10. Dispersion obtainable according to claims 1 to 9.

1 1. Dispersion according to claim 10,

characterized in that

the determined by means of dynamic light scattering mean

Particle diameter 120 to 250 nm.

12. Dispersion according to claim 10,

characterized in that

it contains 35 to 40 wt .-% pyrogenically prepared silica particles having a BET surface area of 250 m ² / g to 350 m ² / g and by means of dynamic light scattering average particle diameter is 130 to 180 nm.

13. coating color containing the dispersion according to claims 9 to 12 and at least one binder.

14. Use of the dispersion according to claims 9 to 12 and the

Coating paint according to claim 13 for the coating of

Ink-absorbing inkjet media.

An ink-receiving medium comprising an ink-receiving layer, wherein the ink-receiving layer comprises the coating color according to claim 13 and a carrier.