DK176562B1 - Dust-free, dispersible compacted or briquetted carbon@ black for colouring building or organic materials - made using processing aid by compacting, pulverising and separating into fractions - Google Patents

Abstract

Production of compacted or briquetted carbon black pigment granulate comprises: (a) mixing the pigment with one or more processing aids; (b) compacting or briquetting the mixture; (c) pulverising the product; (d) separating into two or more fractions; and (e) removing as final product the fraction with at least 85% of particles above 80 (especially above 100) mu m or with size 80-2,000 (especially 100-1,000) mu m and optionally rounding it, and discarding or recycling the other fraction(s).

Description

DK 176562 B1

The present invention relates to a process for preparing formal briquette granules of soot pigments with adjuvants. These granules can be used in the dyeing of building materials such as concrete and asphalt and of organic media such as varnish systems, resins and color pastes.

5 The processing of pigment granules requires the milling of the pigments into primary particles in order to obtain the optimal color impression. The powders thus formed are very strongly dusted, and due to their fineness they tend to adhere and adhere to dosing systems. For toxicologically hazardous substances, it is therefore necessary to take measures to avoid the danger of 10 people and the environment due to the dust formed during processing. However, even in trouble-free inert substances, such as iron oxide pigments, on the part of consumers an ever stronger desire to avoid dust pollution.

Therefore, the avoidance of dust and improved dosing due to better flow properties to obtain a qualitatively uniform color impression when used in building materials and organic media is the aim of handling pigments. This goal is achieved to a greater or lesser extent by the use of granulation processes on pigments.

In addition, structural or spray granulation is usually used. Compression methods have heretofore been less suitable because of the limited dispersibility of the granules thus formed.

20 In principle, pigment consumers require two properties that go in different directions when using pigment granules: mechanical stability of the granulate and good dispersion properties. The mechanical stability ensures good transport properties, both during transport between manufacturer and consumer as well as good dosage and flowability in the use of the pigments. The mechanical stability is induced by high adhesive forces and depends, e.g. by the amount of binder or also by the compression pressure of molding. On the other hand, the dispersibility is affected by a good grinding prior to the granulation (wet and dry grinding), the mechanical energy of incorporation (shear forces) and dispersing aids which immediately reduce the adhesive forces in the dry granulate when incorporated into a medium.

30 However, in pigments, the use of larger amounts of dispersing aids is limited due to the cost / weight ratio of pigment. In addition, a high proportion of additives results in a corresponding decrease in the color strength or the spreading ability. Since the color strength variations are usually below ± 5%, the use of additives is also limited, even when simultaneously acting as a stapler and dispersant aid. Furthermore, the additives must not alter the use characteristics of the final products, such as e.g. building materials, resins and lacquers, in the unfortunate direction, for example by the concrete strength or solidification ratio, by the asphalt compressive or tear strength, and by the resilient strength or notch strength, and by the elastomers (polymers) the elastic properties.

According to the prior art, spraying granulation (spray drying over slab or nozzle) and structural granulating (mixer, swirl layer granulator, plate or drum) can be used as preparation methods for, for example, pigment granules.

In spray-drying granulation, pigment suspensions are used and binders are used. Such methods are described in various patents.

10 In these cases, water-soluble binders are used. Thus, DE-A 3 619 363, EP-A 0 268 645 and EP-A 0 365 046 are based on organic substances such as e.g. lignin sulphonates, formaldehyde condensates, gluconic acids, sutphated polyglycol ethers, while in accordance with DE-A 3 918 694 and US 5 215 583, inorganic salts such as e.g. silicate and phosphate. EP-A 0 507 046 discloses a combination of spray granulation and structure granulation. In DE-A 3 619 363 (column 3, lines 44-47) and EP-A 0 268 645 (column 7, lines 18, 19) the use of a compression method is exempted. In this method, by applying pressure, a strong cohesion of the particles is obtained, so as to obtain good transport stability, but at the same time also lower dispersion properties.

EP-A 0 257 423 and DE-A 3 841 848 disclose the spray granulation using polyorganosiloxanes as hydrophobic, lipophilic additives. The hydrophobic finishing of spray-granulated products results in a granulate with very good flow properties, but which is extremely dusty and also has low wettability with water.

EP-A 0 424 896 discloses the preparation of dust-poor finger granules in a workflow in known intensive mixers. Here, a low wax content is used in combination with emulsifier and wetting agents when applying an aqueous dispersion. As a result, water content is usually obtained from 20 to more than 50%. These granules must first be dried and isolated from the top and bottom grains.

30 DE-A 31 32 303 discloses dust-poor, rice-resistant inorganic pigment granules which are mixed with binders which become liquid under heat and granulated by a sieving process using sieve aid (pressure). Thus, approx. 10-20% of the passed material as fine particle proportion <0.1 mm.

EP-A 0 144 940 discloses dust-poor pigment granules which, from filter sludge by approx. 50% water by the addition of 0.5-10% surfactants and additional mineral oil or wax, which is made liquid, is mixed at 50-200 ° C to the softening point. The process is carried out in intensive mixers and, if necessary, subsequent granulation and drying. In the final product, water is present in an amount of ΙΟΙ 5%, which is unfortunate for incorporation into resins.

DE 4 345 168 A1 discloses a process for producing mold granules of soot pigments in which one or more soot pigments are mixed with one or more auxiliaries. The mixture is subjected to a pressing step and the pressed product is comminuted.

The finely divided product is rounded.

Other methods also have limited utility. The spray granulation due to the droplet formation requires the use of light liquid, ie. thin liquid suspensions. Thus, in the drying process, a greater amount of water must be evaporated than in the frequently used fluidized bed swirl drying of high-pressure pigment filter pastes. This leads to higher energy costs. In the case of pigments prepared in advance by calcination, spray granulation means a further 15 steps of high energy cost. Furthermore, with the spray granulation, a greater or lesser amount of the fine particulate material in the dust filter appears, and this material must be recycled in production.

The structural granulation often also has disadvantages. It can be carried out - based on pigment powder - in mixers under high turbulence, in the fluidized bed process 20 or even by plate and drum granulation. Common to these processes is that the need for binder, mostly water, is high, so that as a subsequent process step a drying must be connected. Here too, granules of different sizes are obtained, especially when there is insufficient binder for the amount of powder available or the actual distribution is not optimal. Then a certain proportion may be too large as granules, while on the other hand too small and thus dusty proportions appear. It is therefore necessary to classify the granules formed with a reflux of upper and lower grains.

The plate granulation leads to a wide particle size spectrum of granules. Where, due to the poor dispersibility of oversized particles, this is not desired, the granulation process must be followed by intensive personnel monitoring and the granulation production must be optimized by manual control of the germ volume. Usually a classification is also made here with the return of upper and lower grains.

Extrusion processes based on pastes result in drying to granules which also because of their size do not ensure optimum dispersibility.

4 DK 176562 B1

DE-A 42 14 195 discloses a method for dyeing asphalt with inorganic pigment granules, in which oil is used as a binder. This is a simple granulation process.

In DE-A 4 336 613 and DE-A 4 336 612, inorganic pigment granules are prepared from pigments by mixing with binders, compression, crushing and granulating. These granules produced in this way are difficult to transport pneumatically and during transport a lot of dust is produced which is undesirable.

Therefore, it is the object of the present application to provide a method which avoids the hitherto described disadvantages of the spray granulation, extrusion granulation, or structure granulation in their application to inorganic pigments, especially soot pigments, and provides sufficiently stable, dosing, dust-poor granules, with preferably the same good dispersants. like the previously known powders.

It has been found that this can be achieved by a multi-stage combination of the mixing, compression, isolation and optionally rounding steps.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a process for the preparation of formal briquette granules of soot pigments with auxiliary agents, the process being characterized in that a) one or more soot pigments are mixed with one or more auxiliaries which promote processing ability; , (c) the molded or briquetted product is comminuted; (d) the comminuted product is separated into two or more fractions by size; (e) the fraction in which at least 85% of the particles are greater than 80 µm, preferably 25 greater than 100 µm, or between 80 and 2,000 µm, preferably between 100 and 1,000 µm, is withdrawn as a product and optionally rounded off in a further step and the other fraction (s) removed from the process or recycled.

Preferred embodiments of the method are set forth in claims 2-11.

Prior to step c), the pressed or briquetted product can preferably be separated into two fractions by size (intermediate step x), after which the coarse fraction in which at least 85% of the particles are greater than 500 µm, preferably 600 µm, can be comminuted in step c ), and the second fine fraction in step d) alone or together with the product of step c) is again separated into two or more fractions.

5 DK 176562 B1

Preferably, only the fine fraction from intermediate step x) is separated into two or more fractions by size in step d), while the coarse fraction from intermediate step x) is comminuted in step c) and then removed from the process as a product.

The intermediate step x may preferably be accomplished by sieving or sieving (mechanical separation). Preferably sieving machines are used.

It is particularly preferred to divide the finely divided product in step d) into two fractions by size, with the fine particle fraction less than 80 µm being withdrawn or recycled in the process and the coarse fraction larger than 80 µm optionally rounded off in a further step.

The finely divided product may also preferably be divided into three fractions according to size 10 in step d), whereby the fine particle and coarse particle fraction is withdrawn from the process or recycled in the process, and the center fraction between 80 and 2,000 µm, especially preferably between 100 and 1,000 µm, particularly preferably between 100 and 500 µm, optionally rounded off in a further step.

The granules preferably have a residual water content of less than 4% by weight, especially preferably less than 2% by weight. This may also be achieved by post-drying.

The rounding step under e) is preferably carried out while removing the dust part.

Preferably, the product obtained after the rounding process in step e) can be further coated with auxiliaries.

When a rounding step is carried out under e), a coarse fraction of particle sizes> 1,500 µm may then be advantageously isolated, which may be recycled in the process.

The soot granules preferably have shaking room weights between 0.1 and 2.5 g / cm 3.

As auxiliaries can be used both inorganic and organic substances.

As auxiliaries, water, salts of the group of phosphates, carbonates, nitrates, sulfates, chlorides, silicates, aluminates and borates, formates, oxalates, citrates and tartrates, polysaccharides, cellulose derivatives such as cellulose ethers, cellulose esters, phosphonocarboxylic acids, modified silanes, silicone oils, oils of biological origin (e.g., rapeseed oil, soybean oil, corn germ oil, olive oil, coconut oil, sunflower oil), refined petroleum oils based on paraffinic and / or naphthenic, alkylphenols, glycols, polyethers, polyglycols, polyglycol derivatives, protein fatty acid condensation products, alkylbenzenesulfonates, alkylnaphthalenesulfonates, lignin sulfonate, sulfated polyglycol ethers, melamine formaldehyde condensates, naphthalene formaldehyde condensates, naphthalene formaldehyde condensates,

6 DK 176562 B1

Further, in the mixture, emulsifiers, wetting agents and dispersants can be used in an amount of 0.01 to 5% by weight, preferably 0.01 to 3% by weight, based on the weight of the pigments used.

In particular, as emulsifiers, emulsifiers having HLB values from 7 to 5 40, especially from 8 to 18, can be used for use in building materials with aqueous systems, such as e.g.

concrete consisting of alkyl, acrylic and hydrophilic intermediate and end groups, such as e.g. amides, amines, ethers, hydroxyl, carboxylate, sulfate, sulfonate, phosphate, amine salt, polyether, polyamide, polyphosphate. The substances can be used individually or in combination with their HLB value.

As wetting agents, alkylbenzene sulfonates, fatty alcohol sulfates, fatty alcohol ether sulfates, fatty alcohol ethoxylates, alkylphenol ethoxylates, alkane, olefin sulfonates are particularly suitable.

As dispersing aids, melamine sulfonates, naphthalene sulfonates, metal soaps, polyvinyl alcohols, polyvinyl sulfates, polyacrylamides, fatty acid sulfates are preferably used.

To enhance stability or to aid in the processing of the granules, it may be advantageous to coat the granules eventually with an additional layer.

This layer may be formed by application of inorganic salts in solution, of polyols, oils or waxes or polyethers, polycarboxylates or cellulose derivatives, preferably carboxymethyl cellulose.

The granules can also be further added to the mixture with preservatives at a concentration of 0.01 to 1% by weight, based on the weight of the pigment. Examples include formaldehyde cleavage compounds, phenolic compounds or isothiazolinone preparations.

Surprisingly, the mold and briquette granules, especially when intended for incorporation into aqueous building material systems such as cement mortar or concrete, are used not only in water-soluble substances as auxiliary, but also water-insoluble substances, such as e.g. oils.

The adjuvants are preferably used in amounts from 0.001 to 10% by weight, especially 30 from 0.01 to 5% by weight, particularly preferably from 0.1 to 3% by weight, based on pigment used.

The auxiliaries may preferably be used in conjunction with additional additives such as e.g. emulsifiers, wetting agents, metal soaps, etc.

7 DK 176562 B1

The pressing or briquetting step b) is preferably carried out on a roller press or die press and preferably at line forces from 0.1 to 50 kN / cm, preferably 0.1-20 kN / cm.

In pressing or briquetting (compression, step b)), an important characteristic size of the compressive force (kN) per cm roller width (line force). The compression between rollers assumes a linear transfer of the pressing force, since no pressing surface can be determined and therefore no pressure (kN / cm2) can be calculated.

The compression is preferably carried out at low line forces. The line forces used are usually preferably in the lower range of the commercially available apparatus, preferably between 0.1 and 50 kN / cm. In particular, linear forces of 0.1-20 kN / cm are preferred. Commercial appliances are e.g. Pharmapaktor 200/50 from the company Bepex GmbH, Leingarten / Germany.

The further separation step x) is preferably carried out with sieving machines, such as e.g. drum screens, swing screens and vibration screens.

The comminution can be carried out with all commercially available comminution assemblies such as crushers, tooth mills, friction rollers and screen granulators.

The finishing step c) is preferably carried out with sieve granulators or sieve mills, in which the material is pressed through a passage sieve having a mesh width of 0.5 to 4 mm, especially preferably from 0.5 to 2.5 mm, especially preferably from 1 to The rotors move, as is well known, rotating or oscillating at a peripheral speed of 0.05 m / sec to 10 m / sec, preferably 0.3-5 m / sec. The distance between the rotor and sieve or hollow disc is 0.1-15 mm, preferably 0.1-5 mm, especially preferably 1 -2 mm.

For example, a Flake Crusher from Frewitt, Freiburg / Switzerland can be used as a comminution apparatus.

After the comminution, the fine particle fraction is separated below 80 μιτι. Preferably, the amount of this fine particle fraction is 10-50 wt%, especially preferably 10-30 wt%. The fine particle fraction is preferably recycled to step b). The remaining proportion is rice-resistant, 30 dosed, stable, dust-poor and has good dispersibility. A further optimization can be achieved by subsequent rounding.

The rounding step under e) is preferably carried out on a turntable, a rotary drum or drum ring drum, on drum sieves or similar apparatus or in a vortex layer or in a sieving system. Here, the dust part can preferably be sucked off or removed in the fluidized bed by air.

8 DK 176562 B1

The process according to DE-A 43 36 613 or DE-A 43 36 612, due to the structure granulation on the turntable, leads to round particles, which are, however, inhomogeneous. They consist of a compact core and one or more buildable outer layers that can be torn off. These products are therefore dusty especially in the pneumatic transport and the flowability is not very good. The products of the process according to the invention do not have these disadvantages, since they consist of homogeneous compact articles of uniform density and strength.

The granules prepared by the process according to the invention are used for dyeing building materials, e.g. concrete, cement mortar and plaster, and for dyeing organic media such as lacquers, resins and color patches, and for producing dispersion paints and slurries.

The granules prepared by the process of the invention are particularly suitable for incorporation into dry cement mortar mixtures and in plaster.

In the present multi-stage process, it is essential that in the first step a sufficiently cohesive homogeneous material be formed by adding the auxiliary in a mixer. The second step then involves briquetting or pressing.

In dyeing building materials, such as concrete with soot pigments, inorganic briquette or mold granules of soot pigments and auxiliaries prepared by the process of the invention are mixed with the building material in an amount of 0.1-10% by weight, preferably 1-5%. % by weight, calculated on cement.

Granules prepared by the process of the invention can also advantageously be used in dispersion dyes and slurries.

By dyeing organic media such as varnish systems, resins and color pastes with soot pigments, inorganic briquette or mold granules of soot pigments made by the process of the invention are mixed with the organic medium in an amount of 0.1 to 10% by weight. , calculated on organic medium.

The test of the dispersibility of building materials is carried out in cement mortar over the color strength measurement on prisms made with white cement: 30 Cement quartz sand ratio 1: 4, water-cement value 0.35, pigmentation height 1.2%, based on cement, used mixer from RK Toni Technik, Berlin, with 5 l mixing bowl, build 1551, speed 140 ο / min, mixture: 500 g cement.

After 100 s, 3 mixture samples (300 g) are taken and sample bodies (5 x 10 x 2.5 cm) are prepared under pressure (300 bar). Hardening of test bodies: 24 hours at 30 ° C and 95% 35 relative humidity with subsequent drying for 4 hours at 60 ° C. Color data measurement via 9 DK 176562 B1

Dataflash 2000 Datacolor International, Cologne, 4 measuring points per stone, 12 measuring points per pigment mixture. The obtained average values are compared with the values for a reference sample. Evaluation of the color distance Eab and the color strength (reference sample = 100%) (DIN 5033, DIN 6174). The dispersibility is rated 5 as good at a color strength difference up to 5% over the reference sample, as satisfactory at a difference up to 10%.

The flow performance test is performed by assessing the outlet ratio of a 100 ml volume funnel with 6 mm aperture in accordance with ASTM test D 1200-88. The flow ratio is denoted as good when the material flows freely. If there is no material outflow or an outflow only after knocking, the flow ratio is considered insufficient.

Determination of the fine particle portion as the screen manor is made on a VA screen according to DIN 4188 with a mesh width of 80 µm on an Alpine 200 LS air jet screen machine. 20 g of sample material is used. The fine particulate material is aspirated over a period of 5 minutes and the amount of coarse particles in the sieve is weighed.

The test of the plastic dispersibility is carried out in accordance with a regulation adapted to DIN 53 775, Part 7, “Priifung von Farbmitteln in weichmacherhaltigen Polyvinylchloride (PVC-P) -formmass; Determination of the dispersion hard by rolling ”.

The pigment being tested is dispersed at 160 ± 5 ° C on a 20 PVC mixed rolling mill. The resulting roller skin is divided and half is then subjected to increased shear forces by rolling at room temperature. In terms of dispersibility, for colored pigments, the color distance ΔΕ according to CIELAB (Din 5033, 6174) between hot and cold rolled PVC skin, or for white pigments, applies the difference in the standard color value Y (DIN 5033) between hot and cold rolled PVC skin. A well dispersible pigment is already dispersed at low shear forces, whereas for the dispersion of a highly dispersible pigment, the increased shear forces are required at the lower temperature rolling. Therefore, the smaller the color distance ΔΕ or the difference in the standard color value ΔΥ, the better the pigment is dispersible.

Especially in granules, dispersibility is of great importance, since granulate particles 30 must first be comminuted before dispersing in the resin. For granules, an aim is as good for dispersibility as for the corresponding pigment powders, so that the characteristics ΔΕ or Y for powder and granules are not significantly different.

The fine dust measurement to assess the strength of granules is carried out in accordance with DIN 55 992. The dusting properties of a granulate can be measured with a 35 Heubach “Dustmeter”. The extraction of fine dust from a rotating drum through which an airflow of defined strength flows through is determined gravimetrically on a fiberglass filter. Measurements after different load times can also determine the course of dust evolution as a function of mechanical impact.

The present invention is further illustrated by the following examples.

EXAMPLE 1 500 g of soda Corasol C 30 (commercial product from Fa. Degussa) or 500 g of soot Monarch 800 (commercial product of Fa. Cabot Corp.) are mixed with ammonium lignin sulfonate and machine oil V 100 in various quantities in a mixer for 18 minutes. The mixture is pressed on a compact type WP50N (Company Alexanderwerk, Remscheid) with different line forces and then comminuted in a finger granulator RFG (Fa. Alexanderwerk, Remscheid) with a screen having a mesh width of 1.5 mm. The finely divided product is separated over a sieve with a mesh width of 250 μτη into two fractions. The fraction above 250 15 μιτι is tested and shows a good flowability (the corresponding powder has a poor flowability). The other data for the fraction as well as the starting powder are shown in Table 1. In addition, the relative color strength of concrete in relation to the pigment content of the granulate (theoretical value) is converted.

EXAMPLE 2 500 g of soot Corasol C 30 (commercial product from Fa. Degussa) is mixed with 8% ammonium lignin sulfate and 1% machine oil V 100 in a mixer for 18 minutes. The mixture is pressed onto a compact type WP50N (Fa. Alexanderwerk, Remscheid) at 7 kN / cm, and then comminuted in a finger granulator RFG (Fa. Alexanderwerk, Remscheid) with a screen having a mesh width of 1.5 mm.

Part of the finely divided product is separated over a sieve with a mesh size of 250 μιτι in two fractions. The fraction above 250 μιτι (60% of the volume) is tested and shows good flowability (the corresponding powder has poor flowability).

The second portion of the finely divided product (about 150 g) including the finial portion is granulated in a 15 cm diameter drum at 60 rpm. minute for 5 minutes.

In this way the finan- cial fraction is 100% granulated. Also, this product has a good flow capability and sufficient dispersibility. The dust conditions in the dust meter, according to Heubach, are clearly different from the two products. The compacted, milled and post-granulated material exhibits 1328 mg of dust, while the compacted, formal and screened but not post-granulated material only develops 548 mg of dust in the test. The starting powder Corasol C 30 develops 2669 mg of dust in the dust meter.

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Claims (11)

13 DK 176562 B1 A process for preparing mold or briquette granules of soot pigments with auxiliary agents, characterized in that a) one or more soot pigments are mixed with one or more auxiliaries which promote processing, b) the mixture is subjected to a pressing or briquetting step, c) it (d) the comminuted product is separated into two or more fractions by size; (e) the fraction in which at least 85% of the particles are greater than 80 µm, preferably 10 greater than 100 µm, or is between 80 and 2,000 µm, preferably between 100 and 1,000 µm, is taken out as a product and optionally rounded off in an additional step and the other fraction (s) are withdrawn from the process or recycled. Process according to claim 1, characterized in that before step c) the pressed or briquetted product from b) is divided into two fractions by size, the coarse fraction, in which at least 85% of the particles are larger than 500 µm, preferably larger than 600 µm, is added to step c) and comminuted, and the fine fraction is added to step d) to be divided into step d) separately or together with the product of step c). Method according to claim 1, characterized in that the finely divided product (d) is divided into two fractions according to size, where the fine particle part less than 80 20 µm is withdrawn or recycled in the process, and optionally the coarse fraction larger than 80 µm is rounded into a subsequent steps. Process according to claim 1, characterized in that the finely divided product is divided into three fractions according to size in step d), the fine particle part and the coarse particle part being taken out or recycled, and optionally the middle fraction 25 is rounded between 80 and 2,000 µm in a further step. Process according to one or more of claims 1-4, characterized in that the rounding step under e) is carried out during removal of the dust part. Process according to one or more of claims 1-5, characterized in that the product obtained according to step d) or optionally the product obtained after rounding in step e) 30 is coated with auxiliaries. Process according to one or more of claims 1-6, characterized in that water, salts from the group of phosphates, silicates, aluminates, borates, polysaccharides and cellulose derivatives, oils of biological origin, refined petroleum oils on paraffin are used as an aid. - and / or naphthenic base, synthetically prepared oils, alkyl phenols, glycols, polyethers, polyglycols, polyglycol derivatives, protein fats, acid benz condensation products, alkyl benzenesulfonates, alkyl naphthalenesulfonates, lignin sulfonated hydrolysates, lignin sulfonated hydrolysates aqueous solutions thereof. Method according to one or more of claims 1-7, characterized in that the auxiliaries are used in amounts from 0.001 to 10% by weight, based on pigment used. Method according to one or more of claims 1-8, characterized in that the pressing or briquetting step b) is carried out on a roller press or matrix press and at line forces of 0.1 to 50 kN / cm, preferably 0.1 20 kN / cm. Method according to one or more of claims 1-9, characterized in that the fi nal in the step (c) is carried out by sieving over a pass sieve with a mesh width of 0.5–4 mm, preferably 0.5–2.5 mm, especially preferably from 1 to 2 mm. Method according to one or more of Claims 1 to 10, characterized in that the rounding step under e) is carried out on a turntable, in a turning drum, in a sieving system or in a vortex layer.