Carbon black dispersion, process for its production, aqueous coating dispersion and aqueous coating

Abstract

Carbon black regrind dispersion, comprising: an aqueous solvent comprising more than 90 wt% water; 30 to less than 60 wt.% of a modified carbon black, wherein the modified carbon black has an STSA between 20 and 300 m 2 / g, measured before treatment, the modified carbon black is modified with a treatment agent containing an organic group and an ionic or ionizable group at a treatment agent concentration between 1.0 and 3.0 µmol / m 2 exhibits; a dispersant concentration of less than 2.4 mg per square meter of soot surface as measured by STSA before treatment; and where less than 10 vol.-% of the soot distributed in the ground material has a particle size of more than 0.5 µm.

Description

Field of invention

[0001] The present disclosure relates to a carbon black regrind dispersion, a process for its production, an aqueous coating dispersion produced from the carbon black regrind dispersion and an aqueous coating. background

[0002] Carbon black pigments are used in a variety of applications, including inks, paints, toners, adhesives, pipes, cables, and color filters. In many cases, the carbon blacks are dispersed in a liquid carrier, which can be either aqueous or non-aqueous. Carbon blacks can be treated with various materials to improve their dispersibility in either aqueous or non-aqueous systems.

[0003] US 2008 / 0087191 A1 concerns dispersions containing a particulate material and a solvent, and optionally a dispersant. The dispersions specified in US 2008 / 0087191 A1 explicitly require a non-aqueous solvent, as the solvent must have a dielectric constant ≤ 50, and this characteristic excludes water in amounts exceeding 50 wt%. The examples in US 2008 / 0087191 A1 explicitly designate the dispersions produced therein as non-aqueous coating compositions. Summary

[0004] In one aspect, a carbon black regrind dispersion is provided, including: an aqueous solvent comprising more than 90 wt% water; 30 to less than 60 wt.% of a modified carbon black, wherein the modified carbon black has an STSA between 20 and 300 m 2 / g, measured before treatment, the modified carbon black is modified with a treatment agent containing an organic group and an ionic or ionizable group at a treatment agent concentration between 1.0 and 3.0 µmol / m 2 exhibits; a dispersant concentration of less than 2.4 mg per square meter of soot surface as measured by STSA before treatment; and where less than 10 vol.-% of the soot distributed in the ground material has a particle size of more than 0.5 µm.

[0005] The soot can also occur at a treatment agent concentration of 1.5 to 3.5, 1.5 to 2.5 or 1.5 to 2 µmol / m³. 2The regrind dispersion may contain modified carbon black particles with an average primary particle size of 15 to 50 nm, and the modified carbon black particles may be treated with an agent comprising an aryl group, a sulfonic acid group or salts thereof, a benzoic acid group or salts thereof, a carboxylic acid group or salts thereof, or a phosphonic acid group or salts thereof. The dispersant may be a non-ionic dispersant, and the regrind may comprise an alkyd or acrylic resin. The treatment agent may be directly bonded to the carbon black. The regrind may have a Brookfield viscosity of less than 700, less than 650, less than 600, or less than 550 mPa·s (cP) at 10 rpm and 25 °C.

[0006] In a second aspect, a carbon black regrind dispersion is provided, including: an aqueous solvent comprising at least 90% by weight water; more than 30 to less than 60 wt% modified carbon black, wherein the modified carbon black is combined with an organic treatment compound having a treatment concentration of between 1 and 3.0 µmol / m³ 2 is treated, the organic treatment compound comprises both an aryl group and an ionic or ionizable group, the modified carbon black is made from untreated carbon black with an STSA of more than 20 m 2 / g and less than 300 m 2 / g is produced; 2.4 mg of dispersant per square meter of soot surface or less; and the carbon black regrind dispersion remains stably dispersed after one week at 52 °C.

[0007] The surface area of ​​the untreated soot is more than 20 m². 2 / g and can also be less than 250, less than 200 or less than 150 m 2The regrind may contain more than 30 to less than 60 wt% of modified carbon black and may contain 40 wt% or more of modified carbon black. It may also contain 0.1, 0.2, 0.5, 1.0, or 1.5 g of dispersant per square meter of carbon black surface or more, and may contain 2.4 mg of dispersant per square meter of carbon black surface or less. The regrind may also contain less than 2.0, less than 1.5, less than 1.0, less than 0.8, less than 0.5, or less than 0.5 mg of dispersant per square meter of carbon black surface. The unmodified carbon black may have a surface area (STSA) of less than 250, less than 200, or less than 150 m². 2 / g, and exhibits an STSA of more than 20 m 2 / g. The regrind can be produced without ball milling and can be mixed into the aqueous carrier using a paddle tip velocity not exceeding 2 m / s, 3 m / s, or 4.2 m / s. The regrind can have a dispersant concentration in mg per square meter of carbon black surface in the range of (1.5 (x-2) 2 + 0.6) + / - 0.5, where x is the treatment concentration in µmol / m 2 corresponds.

[0008] In a third aspect, a carbon black regrind dispersion is provided, comprising 30 to less than 60% of a modified carbon black and less than 2.4 mg of dispersant per square meter of the carbon black surface, wherein the modified carbon black is combined with a treatment agent comprising an organic group and an ionic or ionizable group at a concentration of 2.0 µmol / m³ 2or less treated, the milled material comprises an aqueous solvent comprising at least 90% water, and wherein the sum of the treatment concentration is in µmol / m 2 and the dispersant concentration in mg / m³ 2 2.5 or more. The carbon black granulate dispersion can remain stably dispersed after one week at 52 °C. The surface area of ​​the untreated carbon black can also be less than 250, less than 200, or less than 150 m². 2The regrind may contain more than 30 to less than 60 wt% of modified carbon black and may contain 40 wt% or more. It may also contain 0.1, 0.2, 0.5, 1.0, or 1.5 g of dispersant per square meter of carbon black surface. The regrind may also contain less than 3.5, less than 3.0, less than 2.5, less than 2.0, less than 1.5, less than 1.0, less than 0.8, less than 0.5, or less than 0.5 mg of dispersant per square meter of carbon black surface. The unmodified carbon black may have a surface area (STSA) of less than 350, less than 300, less than 250, less than 200, or less than 150 m². 2The regrind can be produced without ball milling and can be mixed into the aqueous carrier using a blade tip velocity not exceeding 2 m / s, 3 m / s, or 4.2 m / s. The regrind can have a dispersant concentration in mg per square meter of carbon black surface in the range of (1.5 (x-2) 2 + 0.6) + / - 0.5, where x is the treatment concentration in µmol / m³ 2 corresponds.

[0009] Furthermore, the invention relates to aqueous coatings produced from the carbon black ground material dispersions according to the invention.

[0010] Upon inspection according to inspection method A described herein for aqueous coatings, the resulting cured coating can exhibit an opacity of 0.98 or more at a wet film thickness of approximately 0.076 mm. A coating with 1 to 5 wt.% modified carbon black produced from the regrind can exhibit an opacity of 0.95, 0.97, 0.98, or 0.99 or more and can be obtained after the regrind dispersion has been aged for one week at an elevated temperature, for example, 52°C.

[0011] A process for producing a stable aqueous liquid coating comprises mixing non-dispersed carbon black powder in an aqueous, settled coating substrate containing more than 0.0001 wt% and less than 5 wt% of the stable aqueous liquid coating, wherein the stable aqueous liquid coating has a dispersant concentration of less than 2.4 mg per square meter of the carbon black surface, and wherein the liquid coating exhibits an opacity of 0.98 or more at a wet film thickness of 0.0762 mm, and wherein the non-dispersed carbon black powder is suitable for dispersion by stirring the carbon black in the aqueous settled substrate while the paddle tip velocity does not exceed 4 m / s. The process can be carried out in the absence of ball milling or grinding, and the mixing step can use less than 100 watts or less than 50 watts per 200 g of the aqueous liquid coating.The coating may comprise more than 50 wt% aqueous resin, and the resin may be a latex, acrylic, or alkyd resin. The process may use a modified carbon black treated with an organic group comprising a sulfonic acid group or salts thereof, a carboxylic acid group or salts thereof, a benzoic acid group or salts thereof, or a phosphonic acid group or salts thereof. The modified carbon black may have an STSA surface area of ​​more than 20 m². 2 / g and less than 300 m 2 / g, more than 20 m 2 / g and less than 250 m 2 / g or more than 20 m 2 / g and less than 200 m 2 / g. The modified carbon black can have a concentration greater than 1.0, 1.5 or 2.0 µmol / m³. 2 and less than 3.5, 3.0 or 2.5 µmol / m³ 2 containing a treatment agent comprising an organic group that contains an ionic or ionizable group.

[0012] In another aspect, a method for producing an aqueous regrind dispersion is provided, the method comprising: Stirring a non-dispersed modified dry carbon black powder, which contains no grinding media, in an aqueous carrier with a concentration of 30 to less than 60 wt%, based on the final weight of the ground material, to form a carbon black regrind, wherein the modified carbon black is combined with a treatment agent in an amount between 1.0 and 3.0 µmol / m³ 2 is treated, the treatment agent comprises an aryl group and an ionic or ionizable group, the aqueous carrier comprises a solvent that contains more than 90 wt% water and less than 2.4 mg dispersant per square meter of soot surface, and where less than 10 vol% of the soot distributed in the ground material has a particle size of more than 0.5 µm.

[0013] The process can be carried out without the ball grinding or milling step, and the stirring step can use less than 100 watts or less than 50 watts per 200 g of aqueous liquid coating. The process can utilize a modified carbon black treated with an organic group containing a sulfonic acid group or salts thereof, a carboxylic acid group or salts thereof, a benzoic acid group or salts thereof, or a phosphonic acid group or salts thereof. The modified carbon black can have an STSA surface area of ​​more than 20 m². 2 / g and less than 300 m 2 / g, more than 20 m 2 / g and less than 250 m 2 / g or more than 20 m 2 / g and less than 200 m 2 / g. The modified carbon black can have a concentration greater than 1.0, 1.5 or 2.0 µmol / m³. 2 and less than 3.5, 3.0 or 2.5 µmol / m³ 2a treatment agent comprising an organic group containing an ionic or ionizable group. The carbon black can be dispersed at a concentration of 40% by weight. The concentration of the dispersant can be less than 1.7 mg of dispersant per square meter of carbon black surface. Brief description of the drawings Fig. Figure 1 is a copy of a photograph showing the opacity of eight different pigmented coatings; Fig. 2 is a copy of a photograph showing the opacity of another pigmented coating; Fig. Figure 3 graphically represents the blackness of several embodiments of coatings; Fig. Figure 4 graphically represents the opacity of several coating designs; Fig. Figure 5 graphically represents the blue hue values ​​of several coating designs. Fig.6A and Fig. 6B are copies of photographs showing the viscosity of two different embodiments of the milled material; Fig. 7A, Fig. 7B, Fig. 7C and Fig. 7D provides the mass colour tone and colour composition values ​​for embodiments of the acrylic and alkyd resin coatings; Fig. 8A, Fig. 8B, Fig. 8C and Fig. 8D provides the mass colour tone and colour composition values ​​for additional embodiments of the acrylic and alkyd resin coatings; Fig. 9A, Fig. 9B, Fig. 9C and Fig. 9D provides the mass colour tone and colour composition values ​​for additional embodiments of the acrylic and alkyd resin coatings; Fig. 10A and Fig. 10B are copies of electron microscope images showing the dispersion of soot particles from two different embodiments; and Fig.Figure 11 graphically represents the viscosity values ​​for two different embodiments of the ground material. Detailed description

[0014] Various processes, treatments, and additives can be used to disperse carbon black particles in aqueous systems. For example, dispersants can be added to an aqueous carrier, and carbon blacks can be treated with compounds to improve their dispersibility in the aqueous carrier. In general, dispersibility can be improved by increasing the concentration of the dispersant, the treatment concentration of the carbon black, or both. Recognizing that excessive treatment and dispersant levels can adversely affect the properties of a liquid coating, as well as contribute to costs, this disclosure provides details regarding dispersions and processes that utilize certain modified carbon blacks in specific aqueous systems to reduce the amount of treatment and dispersant that would otherwise be required.A low-energy stir-in system is described in which a modified carbon black can be stirred into an aqueous system to produce a stable dispersion without the need for the high-energy grinding processes that are normally employed. The discovery of a stable aqueous dispersion that combines a low level of treatment and low dispersant concentrations provides an economical and flexible system for the production of liquid regrind and coatings.

[0015] In one aspect, a treated (modified) carbon black is stirred into an aqueous support to produce a liquid aqueous (water-based) coating. The modified carbon black can be dispersed directly into the aqueous support without the energy-intensive milling that is normally necessary to disperse unmodified carbon blacks in aqueous supports. The modified carbon blacks described here can have relatively low concentrations of bound functional groups and require no or minimal amounts of dispersants in the aqueous support. For example, the treated carbon blacks can have a treatment agent concentration of more than 1.0, 1.25, 1.5, or 2.0 µmol / m³. 2 and less than 3.0, 2.5, 2.0 or 1.925 µmol / m³ 2 to be modified. In some embodiments, the carbon blacks exhibit a statistical surface thickness (STSA or t-surface, measured according to ASTM D 6556) in the range between 20 m before modification or surface treatment.2 / g and 300 m 2 In a number of processes, non-dispersed dry carbon black powder can be mixed directly into an aqueous coating composition, thereby eliminating the intermediate step of producing a regrind that is subsequently introduced into an aqueous carrier to create a liquid coating. In another set of embodiments, a regrind with a low viscosity and a high modified carbon black content can be produced and then introduced to create a liquid aqueous coating.

[0016] Carbon black is used to provide pigmentation in a wide variety of materials. Coatings can enhance the properties of many surfaces, offering functional, decorative, or protective improvements, for example. Surfaces can include substrates such as metal, plastic, glass, wood, and paper. Some of the products that can benefit from coatings include cars, boats, aircraft, piping, appliances, machinery, furniture, packaging, and electronic displays.

[0017] Most coatings are applied as either liquids or solids. Powder coatings, for example, are applied as a solid, while many coatings are applied as a liquid that can then be converted to a solid. As used here, a "liquid coating" is a liquid coating dispersion containing a dispersed pigment intended for application to a substrate. A liquid coating comprises a liquid carrier and additive components that may be dissolved, dispersed, or suspended within it. A liquid coating is typically converted to a solid coating by drying after application to a substrate. A solid coating, or "coating," is not a liquid but may contain traces of solvents or other liquids. The pigment particles in a coating are fixed and cannot move freely.The conversion from a liquid coating to a coating can be achieved, for example, by evaporating a solvent and / or polymerizing a resin or other polymeric material. A liquid coating is in a state where it can be applied to a substrate without further dilution, unlike a granulated material, which must be primed before application. Liquid coatings can contain a liquid phase or solvent, one or more binders, and one or more pigments. Additionally, a variety of additives can be used, including dispersants, defoamers, wetting agents, coalescing agents, rust inhibitors, and / or antimicrobials. The liquid phase plus the binder is referred to as the carrier. The carrier may also contain non-pigments, such as dispersants, wetting agents, and buffers.Liquid coatings can be aqueous or non-aqueous. As used herein, the solvent fraction (the liquid portion that evaporates when the final coating dries or cures) in an aqueous or water-based coating contains at least 90 wt% water, and in many cases, the solvent system comprises more than 95 wt% or more than 99 wt% water. Similarly, aqueous or water-based coatings may contain more than 50 wt%, more than 80 wt%, or more than 90 wt% water, based on the total mass of the aqueous or water-based coating. Aqueous dispersions typically have higher dielectric constants than non-aqueous dispersions, and in many cases, the dispersions or water-based coatings described herein exhibit dielectric constants of more than 50, more than 60, or more than 70, and up to the dielectric constant of water, approximately 80.

[0018] The pigments in a coating can impart opacity and color, and can also modify other properties such as gloss, mechanical strength, and durability. Pigments also influence the properties of a liquid coating, such as viscosity. Pigments like carbon black can be difficult to disperse in a liquid like water, and a high concentration of carbon black granules is often used to create the liquid coating. Previous attempts to disperse the carbon black directly into the final topcoat required too much energy, resulting in the destruction of the water-based latex emulsion. When a pigment like carbon black is already dispersed in a granulate, adding it to the liquid coating is generally easier than creating a liquid aqueous coating directly from undispersed carbon black powder.Ground materials can contain a high concentration of pigments, such as carbon black, of at least 30 to 58 wt.%, while the liquid coating contains a lower concentration of pigment, usually of 0.5 to 3 wt.%.

[0019] In the field of coatings, liquid coatings, including modified and unmodified carbon blacks, are often produced by ball milling the carbon blacks in a carrier to ensure proper dispersion. The carbon black is typically added to an Eiger mill or other media mill along with grinding media, water, a resin, an antifoaming agent, a coalescing agent, and other optional materials that promote stable dispersion. The mill can be operated for up to several hours at high power. Typically, more than 100 watts of power are required to produce a 200 g sample of the milled material. The grinding media are filtered from the milled material after the dispersion process is complete. The milled material may contain more than 30 wt% of the treated carbon black.The regrind dispersion can be applied as a liquid coating by diluting the regrind with a carrier containing an aqueous solvent (water), a resin, dispersant, wetting agent, and other materials that may vary depending on the application. Although highly treated carbon blacks (more than 10 µmol / m) 2 ) stable aqueous dispersions can be provided, it has been found that the combination of heavily treated carbon black and some resins, such as acrylic resins, can lead to poor coverage in coatings.

[0020] The modified carbon blacks and liquid coatings described here possess properties that eliminate the need for high-energy ball milling. A stirring or agitation process does not require the addition of glass beads or other media that would need to be filtered from the resulting dispersion. Stirring can be performed using a mixer, such as a paddle mixer or a high-speed mixer. Stirring can require less energy than conventional ball milling, meaning that dispersions or emulsions are not destroyed by the high-energy milling process.In many embodiments, the power required to stir in the modified carbon black particles is less than 100 watts, less than 70 watts, less than 50 watts, or less than 40 watts for a 200 g sample, and stable dispersions can be achieved in less than three hours, less than two hours, or less than one hour at these power levels. In some embodiments, the mixer speed can be limited to a mixing blade tip velocity of less than 10 m / s, less than 5 m / s, less than 3 m / s, or less than 2 m / s. Stirring need not raise the temperature of the dispersion, as is the case with pellet milling. For example, in some embodiments, the stirring process can raise the temperature of the liquid carrier by less than 10 °C, less than 5 °C, or less than 1 °C.In contrast, milling processes can increase the temperature of the liquid carrier by more than 10 °C, which can lead to a number of problems, including gelling of the mixture.

[0021] The modified carbon black particles described here can remain dispersed in an aqueous system for months or years. As used here, a stable dispersion is one in which there is no statistically significant decrease in the opacity of a coating prepared from the dispersion containing 1 wt% carbon black after aging the dispersion for one week at an elevated temperature, e.g., 52 °C. If the dispersion contains more than 1 wt% modified carbon black, as in the case of regrind, the dispersion is aged and then coated in an aqueous substrate with a compatible resin containing 1 wt% carbon black to verify the opacity. After drying, the coating contains approximately 3 wt% carbon black.As used herein, “coating” includes liquid coatings produced by diluting a milled material, as well as liquid coatings produced by directly dispersing a non-dispersed pigment in a liquid carrier substance.

[0022] In several embodiments, a modified carbon black pigment can be stirred directly into an aqueous liquid carrier to produce a stable liquid aqueous coating, such as paint or primer. The coating product can be a liquid aqueous coating with a dispersed pigment content of, for example, 1 wt%, 2 wt%, 3 wt%, or 4 wt%. The liquid aqueous coating can be produced without an intermediate step involving the generation of regrind. In one embodiment, a liquid coating containing 1 wt% to 5 wt% modified carbon black can be produced directly from the modified carbon black without generating an intermediate dispersion (regrind) having a carbon black concentration exceeding 10 wt%.Whereas a paint manufacturer might previously have needed several different regrinds to ensure compatibility with various coating compositions, a single dry modified carbon black can replace several regrinds because it contains no potentially incompatible components, such as incompatible resins. Dry modified carbon black can be shipped at a lower cost than regrind containing an equivalent amount of carbon black, and the dry material can also remain stable for a longer period. In addition to the dry powder form, non-dispersed modified carbon black can also be supplied in alternative non-dispersed forms, such as a slurry or gel, which can be stirred into the liquid carrier to form the liquid coating.

[0023] In a further series of embodiments, a highly loaded regrind is produced using the modified carbon blacks described herein. The regrind can contain modified carbon black in concentrations of more than 30 wt.%, more than 35 wt.%, or 40 wt.% or more, and can still achieve a usable viscosity (at 10 rpm, unless otherwise specified) of less than 1100 mPa·s (cP), less than 1000 mPa·s (cP), less than 800 mPa·s (cP), less than 700 mPa·s (cP), less than 650 mPa·s (cP), less than 600 mPa·s (cP), or less than 560 mPa·s (cP). In some embodiments, the regrind can be limited to a modified carbon black concentration of less than 60 wt.% or less than 50 wt.%. Dispersion viscosities are measured using a Brookfield DV-II+ viscometer (Brookfield Engineering Laboratories, Middleboro, MA) using the following procedure.

[0024] After the instrument is switched on, the chiller is turned on and the temperature is set to 25 °C. The instrument is then zeroed using the auto-zero procedure, as instructed by the instrument's display. A spindle is selected by pressing the "Set Spindle" function until the chosen spindle (#3 is used here unless otherwise specified) is highlighted. The "Set Spindle" function is pressed again to confirm the selection. A small sample cup is partially filled with the dispersion to be tested. If a disk geometry (such as #3) is used, the disk is inserted into the dispersion and gently rotated to release any air trapped beneath the disk. Cartridge-shaped geometries can be attached directly to the spindle.The sample cup is then inserted into the enclosed holder on the instrument holder, and if not already attached, the geometry is screwed onto the spindle. Using a pipette, the sample cup is filled to approximately 2.5 mm from the top, and the speed is set to 10 revolutions per minute. The motor is switched on, and the system is equilibrated for one minute at 10 rpm. This is repeated at 20 rpm, 50 rpm, and 100 rpm. After equilibration for one minute at 100 rpm, the test is complete, and the motor is switched off.

[0025] To achieve a specific carbon black concentration in a liquid aqueous coating, a higher carbon black content in a milled material allows for the use of a smaller quantity of material compared to a material with a lower carbon black concentration. Milled materials with higher carbon black content, if stable, can therefore reduce costs, for example, in shipping and storage. At these higher concentrations, the milled materials generally become too viscous to be processed and may be too viscous to pass through a ball mill. For example, to fit through an Eiger mill, milled materials containing carbon blacks with a medium structure are generally limited to a carbon black concentration of around 25%, unless large quantities of dispersant are used. The modified carbon blacks described here provide lower viscosities at higher quantities.Since the modified carbon blacks can be stirred into a granulated material instead of being ground, higher viscosities can be tolerated in the manufacturing process. For example, a carbon black with an STSA surface area of ​​85.5 m² can be produced. 2 / g (STSA before treatment) and a primary particle size of 25 nm, which is approximately 1.925 µmol / m 2When treated with sulfanilic acid, the material readily forms a pourable regrind with a dispersant concentration of less than 2.4 mg per square meter of carbon black surface (STSA before treatment) and a quantity of 40 wt% modified carbon black. This allows for a reduction of approximately 28.5% in the volume of regrind required to produce an equivalent liquid coating, compared to a conventionally regrinded product (25% carbon black). This also means that the composition of the liquid coating allows for more careful control of the types and concentrations of components, such as resins and dispersants, present in the finished liquid coating, as the more concentrated regrind (relative to carbon black) contributes smaller quantities of these materials to the finished aqueous liquid coating. In addition to eliminating or reducing the amount of regrind required, the mixing power (speed) can be significantly reduced.For example, some embodiments of the carbon blacks described herein can be suitably dispersed by mixing at a mixing blade tip speed of less than 10 m / s, less than 5 m / s, less than 4 m / s, less than 3 m / s, or less than 2 m / s. In contrast, currently used modified and unmodified carbon black pigments are usually produced by grinding and mixing at a peak speed of more than 10 m / s, in the presence of an increased concentration of dispersing agent.

[0026] Several measurable optical factors can be used to evaluate coatings containing pigments such as carbon black. Color can be represented three-dimensionally by measuring the color depth (blackness) (L*), blue / yellow (b*), and red / green (a*). An L* value of 0 would be pure black, while higher values ​​are whiter. The liquid coatings described here can result in a coating with an L* value of 5 or less, 4.5 or less, 4 or less, 3.5 or less, or 3 or less. A negative b* value indicates blue undertones, while a positive b* value is yellow. The liquid coatings described here can result in a coating with a b* value of -0.2 or less, -0.3 or less, -0.4 or less, or -0.5 or less. A negative a* value indicates greener undertones, while a positive a* value indicates redder undertones. These values ​​can be measured in a laboratory using instruments such as a Hunter Lab Scan 6000.Another important factor in evaluating a carbon black for use in a coating is the coating's "opacity." Preferred coatings have the ability to completely or substantially mask or obscure the substrate to which they are applied. Many embodiments of the coatings described herein are suitable for masking the substrate with a very thin coating and can result in coatings exhibiting opacity values ​​of 0.95 or greater, 0.97 or greater, 0.98 or greater, 0.99 or greater, and 1 in thin 0.0254 mm coatings. Opacity can be measured using a Leneta® half-black, half-white lacquer test chart or a BYK Opacity Chart #2813. The coating's opacity is the ratio of the optical density on the white area to the optical density on the black area.

[0027] Soot is a well-known term in engineering and includes sewer soot, furnace soot, gas soot, and flame soot. Soot from a variety of suppliers can be used. Some commercially available carbon blacks are sold under the Regal®, Black Pearls®, Elftex®, Monarch®, Mogul®, Spheron®, Sterling® and Vulcan® brands and are available from Cabot Corporation (such as Black Pearls® 1100, Black Pearls® 1000, Black Pearls® 900, Black Pearls® 880, Black Pearls® 800, Black Pearls® 700, Black Pearls® 570, Black Pearls® L, Elftex® 8, Elftex® 320, Monarch® 1100, Monarch® 1000, Monarch® 900, Monarch® 880, Monarch® 800, Monarch® 700, Mogul® L, Regal® 330, Regal® 400, Regal® 660 and Vulcan®). Other commercially available carbon blacks include, but are not limited to, carbon blacks sold under the Raven®, Statex®, Furnex® and Neotex® brands, the CD and HV series available from Columbian Chemicals, and the Corax®, Durax®, Ecorax® and Purex® products available from Orion Engineered Carbons.

[0028] The carbon blacks described here can exhibit a certain range of STSAs. As used herein, the STSA of a modified carbon black means the STSA of the carbon black before modification. In some embodiments, the modified carbon blacks exhibit an STSA between approximately 10 m 2 / g and approximately 350 m 2 / g, between approximately 20 m 2 / g and approximately 300 m 2 / g or between approximately 30 m 2 / g and approximately 150 m 2 / g. In one embodiment, a soot with an STSA of 85.5 m showed 2 / g good results. If the desired surface finish is not immediately available for the intended application, it is known to those skilled in the art that the modified carbon black can be subjected to comminution or a comminution process, such as shot or jet milling or sonication, to reduce the pigment to a smaller particle size, if desired. The modified carbon black can also have a variety of primary particle sizes known in the prior art. For example, the carbon black can have a primary particle size of between approximately 5 nm and approximately 100 nm, including approximately 10 nm to approximately 80 nm and 15 nm to approximately 50 nm. In some embodiments, the carbon black can have a primary particle size of less than 200 nm, less than 100 nm, or less than 75 nm.Furthermore, the carbon black can exhibit a wide range of dibutyl phthalate adsorption (DBP, as defined by ASTM D2414) values, which are a measure of the pigment's structure or branching. For example, carbon black can have a DBP value of approximately 25 to 400 ml / 100 g, including approximately 30 to 200 ml / 100 g and approximately 50 to 150 ml / 100 g. In aqueous dispersions, such as milled materials and liquid coatings, the modified carbon black particle dispersions can have a D90 of less than 0.6 µm, for example, 0.1 to 0.6 µm, 0.1 to 0.4 µm, or 0.15 to 0.5 µm.

[0029] The carbon black prior to treatment may also be carbon black that has been oxidized with an oxidizing agent to introduce ionic and / or ionizable groups onto the surface. Carbon blacks produced in this manner have been shown to have a higher degree of oxygen-containing groups on the surface. Oxidizing agents include, but are not limited to, oxygen gas, ozone, NO₂ (including mixtures of NO₂ and air), peroxides such as hydrogen peroxide, persulfates including sodium, potassium, or ammonium persulfate, hypohalites such as sodium hypochlorite, halites, halates, perhalates (such as sodium chlorite, sodium chlorate, or sodium perchlorate), oxidizing acids such as nitric acid, and transition metal-containing oxidizing agents such as permanganate salts, osmium tetroxide, chromium oxides, or cerium(IV) ammonium nitrate. Mixtures of oxidizing agents may also be used, particularly mixtures of gaseous oxidizing agents such as oxygen and ozone.Additionally, carbon blacks produced using other surface modification processes can be used to introduce ionic or ionizable groups onto a pigment surface, such as chlorination and sulfonylation.

[0030] The carbon black can be a modified carbon black with at least one bound organic group. The organic group can be directly bound. A directly bound group is one that is chemically bonded to the carbon black and not simply associated with it. An organic group is considered directly bound to a carbon black if more than 75% of the organic group remains on the carbon black when it is rinsed with deionized water.

[0031] The modified carbon black can be produced using any process known to a person skilled in the art such that organic chemical groups are bonded to the pigment. For example, the modified pigments can be produced using the processes described in U.S. Patents Nos. 5,554,739; 5,707,432; 5,837,045; 5,851,280; 5,885,335; 5,895,522; 5,900,029; 5,922,118; 6,042,643; and 6,337,358, the descriptions of which are incorporated herein by reference in their entirety. These processes provide a more stable bond of the groups to the carbon black compared to the dispersion process, for example, using polymers and / or surfactants. Other methods for producing the modified carbon blacks include reacting a carbon black with available functional groups with a reagent comprising the organic group, as for example in US patent no. 6,723,783, which is incorporated herein in its entirety by reference.Such functional pigments can be prepared using the methods described in the literature references above. Additionally, modified carbon black-containing functional groups can also be prepared according to the methods described in U.S. Patents Nos. 6,831,194 and 6,660,075, U.S. Patents Nos. 2003-0101901 and 2001-0036994, Canadian Patent No. 2,351,162, European Patent No. 1394221 and PCT Publication WO 04 / 63289, as well as in N. Tsubokawa, Polym. Sci., 17, 417, 1992, each of which is incorporated in its entirety by reference.

[0032] The organic group of the modified carbon black can be a group that enables the modified carbon black to be dispersible in the aqueous carrier of a selected liquid coating or regrind. The organic group can contain an ionized or ionizable group. As used here, an organic group used to treat a carbon black prior to the formation of an aqueous dispersion, for example by diazonium chemistry, is not considered a dispersant in the aqueous liquid dispersion produced from the modified carbon black.

[0033] The binding (treatment) concentration of the organic group on the modified carbon black should be sufficient to provide a stable dispersion of the modified carbon black in the aqueous carrier. Binding concentrations are provided as moles of organic group per area (STSA) of carbon black. For example, organic groups with a concentration of 0.1 to 10.0 µmol / m² can be used. 2 , 0.2 to 5.0 µmol / m 2 , 0.5 to 2.5 µmol / m 2 , 0.5 to 2.0 µmol / m 2 , 0.5 to 1.5 µmol / m 2 , 1.5 to 3.0 µmol / m 2 , 1.5 to 4.0 µmol / m 2 , 1.5 to 4.5 µmol / m 2 or 1.0 to 2.0 µmol / m³ 2 They are bound. In some embodiments, the binding concentration (level of attachment) can be greater than 0.1 µmol / m³. 2 and less than 3.0 µmol / m³ 2 be or greater than 0.1 µmol / m³ 2 and less than 2.0 µmol / m³ 2The groups, including ionic or ionizable groups, can also be quantified in terms of equivalents per area. These bond concentrations can be determined by methods known to a person skilled in the field, such as elemental analysis.

[0034] The groups can be attached to the carbon blacks by processes such as diazonium chemistry, azo chemistry, peroxide chemistry, sulfonation, and cycloaddition chemistry. Diazonium processes disclosed in one or more of the references cited can be adapted to provide a reaction of at least one diazonium salt with a carbon black pigment, for example, a crude organic black pigment that has not yet been surface-modified with bonding groups. A diazonium salt is an organic compound containing one or more diazonium groups. In some processes, the diazonium salt can be prepared prior to the reaction with the organic black pigment material or, more preferably, prepared using in situ techniques such as those described in the cited references.In situ preparation also allows the use of unstable diazonium salts, such as alkyl diazonium salts, and avoids unnecessary handling or manipulation of the diazonium salt. In some methods, both the nitrous acid and the diazonium salt can be generated in situ.

[0035] A diazonium salt, as known in the art, can be produced by reacting a primary amine, a nitrite, and an acid. The nitrite can be any metal nitrite, preferably lithium nitrite, sodium nitrite, potassium nitrite, or zinc nitrite, or any organic nitrite, such as isoamyl nitrite or ethyl nitrite. The acid can be any acid, inorganic or organic, that is effective in the production of the diazonium salt. Preferred acids include nitric acid, HNO₃, hydrochloric acid, HCl, and sulfuric acid, H₂SO₄. The diazonium salt can also be produced by reacting the primary amine with an aqueous nitrogen dioxide solution. The aqueous nitrogen dioxide solution, NO₂ / H₂O, can provide the nitrous acid required to produce the diazonium salt.In general, the preparation of a diazonium salt from a primary amine, a nitrite, and an acid requires two equivalents of the acid, based on the amine. In an in situ process, the diazonium salt can be prepared using one equivalent of the acid. If the primary amine contains a strong acid group, the addition of a separate acid may be unnecessary in some processes. The acid group or groups of the primary amine can provide one or both of the required acid equivalents. If the primary amine contains a strong acid group, preferably zero to one equivalent of additional acid can be added to a process to prepare the diazonium salt in situ. An example of such a primary amine that has exhibited exceptional properties is para-aminobenzenesulfonic acid (sulfanilic acid).

[0036] The surface-modified carbon blacks can contain a carbon black pigment having at least one bonded organic group. The modified carbon black can have at least one organic group with the formula -XZ, where X, which is a first chemical group directly bonded to the carbon black, can be an arylene group, a heteroarylene group, an aralkylene group, or an alkarylene group, and Z is a second chemical group. Z can be non-polymeric. For example, Z can be at least one ionic group or at least one ionizable group.

[0037] As previously stated, group X can be an arylene or heteroarylene group, an aralkylene group, or an alkarylene group. X can be directly bonded to the pigment and is further substituted with the Z group. X can be a connecting group (e.g., a connecting diradical) that is preferably bonded directly between the pigment surface and the Z group. The arylene and heteroarylene groups can be aromatic groups, including, but not limited to, unsaturated cyclic hydrocarbons containing one or more rings. For the heteroarylene groups, one or more ring carbon atoms of the aromatic group are substituted by a heteroatom. The heteroatoms are not carbon atoms, such as N, S, O, or others. The hydrogen atoms of the aromatic group can be substituted or unsubstituted. As stated, X can be a heteroarylene group.It has been shown that the use of a diazonium chemistry route, including heterocyclic diazonium salts, for the treatment of organic black pigment surfaces, such as black perylene surfaces, can facilitate the binding of surface modification groups.

[0038] The heteroarylene group can be a compound group that includes, for example, at least one heterocyclic ring containing one or more heteroatoms (e.g., one, two, three, or more). The heterocyclic ring can, for example, contain 3 to 12 ring element atoms, or 5 to 9 ring elements, or be a 5-, 6-, 7-, or 8-membered ring. The heterocyclic ring can, for example, contain at least one carbon atom, at least two carbon atoms, or any other number of carbon atoms. If multiple heteroatoms are used in a heterocyclic ring, the heteroatoms can be the same or different. The heterocyclic group can contain a single heterocyclic ring or fused rings that contain at least one heterocyclic ring.The heteroarylene group can be, for example, imidazolylene, pyrazolylene, thiazolylene, isothiazolylene, oxazolylene, isoxazolylene, thienylene, furylene, fluorenylene, pyranylene, pyrrolylene, pyridylene, pyrimidylene, indolylene, isoindolylene, tetrazolylene, quinolinylene, isoquinolinylene, quinazolinylene, carbazolylene, purinylene, xanthenylene, dibenzofurylene, 2H-chromenylene, or any combination thereof. X can also represent an arylene group, such as phenylene, naphthylene, biphenylphenyl, anthracene, and the like. If X represents an alkylene group, examples include, but are not limited to, substituted or unsubstituted alkylene groups, which may be branched or unbranched. For example, the alkylene residue could be a C1-C group. 12 -group, such as methylene, ethylene, propylene or butylene, or other alkylenes.

[0039] Group X can also be substituted with groups other than Z, such as one or more alkyl or aryl groups. Furthermore, group X can be substituted with, for example, one or more functional groups. Examples of functional groups include, but are not limited to, R, OR, COR, COOR, OCOR, carboxylates, halogens, CN, NR₂, SO₃H, sulfonates, sulfates, NR(COR), CONR₂, NO₂, PO₃H₂, phosphonates, phosphates, N-NR, SOR, NSO₂R, where R, which can be the same or different, can be hydrogen, branched or unbranched C₁-C₁. 20 , substituted or unsubstituted, saturated or unsaturated hydrocarbons, for example alkyl, alkenyl, alkynyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted alkaryl or substituted or unsubstituted aralkyl.

[0040] As already indicated, group Z can be at least one ionic group or ionizable group. Group Z can also comprise a mixture of an ionic group and an ionizable group. The ionic group can be either anionic or cationic and can be associated with a counterion of opposite charge, including counterions such as Na. + , K + , Li + , NH 4+ , NR 4+ , Acetate, NO 3- , SO4 2- , R'SO 3- , R'OSO 3- , OH - and Cl -, where R' represents hydrogen or an organic group, such as a substituted or unsubstituted aryl and / or alkyl group. The ionizable group can be one capable of forming an ionic group in the medium used. Anionizable groups can form anions, and cationizable groups can form cations. Ionic groups include those described in US Patents 5,698,016, 5,837,045, and 5,922,118, the disclosures of which are incorporated herein in full by reference. The anionic groups are negatively charged ionic groups that can be formed from groups with ionizable substituents capable of forming anions (anionizable groups), such as acidic substituents. They can also be the anion in the salts of ionizable substituents. Representative examples of anionic groups include -COO-, -SO3-, -OSO3-, -HPO3-, and -OPO3-. -2 and -PO3 -2The anionic group can include a counterion, which is a monovalent metal salt, such as a Na⁺. + Salt, a K + salt or a Li + The salt may be included. The counterion can also be an ammonium salt, for example NH₄⁺. 4+ Salt. Representative examples of anionizable groups include -COOH, -SO3H, -PO3H2, -R'SH, -R'OH, and -SO2NHCOR', where R' represents hydrogen or an organic group, such as a substituted or unsubstituted aryl and / or alkyl group. Cationic groups are positively charged ionic groups formed from ionizable substituents that can form cations (cationizable groups), such as protonated amines. For example, alkyl or arylamines can be protonated in acidic media to form ammonium groups -NR'2H. +to form, where R' represents an organic group, such as a substituted or unsubstituted aryl and / or alkyl group. Cationic groups can also be positively charged organic ionic groups. Examples include quaternary ammonium groups (-NR' 3+ ) and quaternary phosphonium groups (-PR' 3+ Here, R' represents hydrogen or an organic group, such as a substituted or unsubstituted aryl and / or alkyl group. The cationic group can comprise an alkylamine group or a salt thereof, or an alkylammonium group.

[0041] Group Z can comprise at least one carboxylic acid group or salt thereof, at least one sulfonic acid group or salt thereof, at least one sulfate group, at least one phosphonic acid group or salt thereof, at least one alkylamine group or salt thereof, or at least one alkylammonium group. Since it is preferred that group X be a heteroarylene group or an arylene group, the bonded organic groups of formula -XZ can include, but are not limited to, heteroarylcarboxylic acid groups, heteroarylsulfonic acid groups, arylcarboxylic acid groups, arylsulfonic acid groups, or salts thereof. For example, the bonded organic group can comprise an imidazolylcarboxylic acid, an imidazolylsulfonic acid group, a pyridinylcarboxylic acid group, a pyridinylsulfonic acid group, a benzenecarboxylic acid group, a benzenedicarboxylic acid group, a benzenetricarboxylic acid group, a benzenesulfonic acid group, or salts thereof.The bound organic group can also be a substituted derivative of one of these.

[0042] As used here, dispersants are substances that can be used in aqueous systems to facilitate the formation of a dispersion of otherwise non-dispersible carbon black particles. Dispersants strongly associate with particles and are selected for their ability to keep particles apart. Dispersants may contain surfactants, functionalized polymers, and oligomers. Dispersants can be nonionic or ionic, and may contain both anionic and cationic dispersants. Nonionic dispersants are preferred, and among ionic dispersants, anionic dispersants are preferred. Dispersants can be amphiphilic and may be polymeric or include a polymeric group. Dispersants do not include other additives that may be used in aqueous coatings, such as wetting agents, defoaming agents, and co-solvents.

[0043] The concentration of dispersants in a milled material or aqueous coating can be measured in various ways known to experts in the field. It is assumed that the amount of dispersant required to adequately disperse carbon black is more accurately a function of the surface area of ​​the particles in the dispersion, rather than the mass of the particles. Therefore, unless otherwise specified, the concentration of a dispersant in a given dispersion should be expressed in units of mass of dispersant per total surface area (STSA) of carbon black in the dispersion. For example, the units might be milligrams of dispersant per square meter of carbon black surface area, as determined by STSA.Since it can be difficult to accurately determine the surface area of ​​a modified (treated) carbon black in the case of a dispersion comprising a modified carbon black, the area of ​​the corresponding untreated carbon black is used when the concentration of a dispersing agent in the dispersion is specified.

[0044] Specific examples of polymeric dispersants include synthetic polymeric dispersants. Ethoxylates are commonly used as dispersants in aqueous compositions. For example, alkylphenol ethoxylates and alkyl ethoxylates are used. Examples include PETROLITE® D-1038 from Baker Petrolite. Polymers and related materials that can be used as dispersants and additives in aqueous coatings are contained in Evonik's Tego products, Lyondell's Ethacryl products, BASF's Joncryl polymers and EFKA dispersants, and BYK's Disperbyk® and Byk® dispersants. Exemplary dispersants that can be used include DisperBYK182, Disperbyk 190, or Disperbyk 192, all available from BYK Chemie; Solsperse™ dispersants, available from Lubrizol, including 46000; and EFKA4585, ELKA4550 and EFKA4560 from Ciba, however, are not limited to these.

[0045] Various rheology modifiers can also be used in conjunction with the aqueous coating composition to adjust the viscosity of the composition and to provide other desirable properties. Suitable compounds include, but are not limited to, water-soluble polymers and copolymers such as gum arabic, polyacrylate salts, polymethacrylate salts, polyvinyl alcohols (Elvanols from DuPont, Celvoline from Celanese), hydroxypropylene cellulose, hydroxyethylcellulose, polyvinylpyrrolidone (such as Luvatec from BASF, Kollidon and Plasdone from ISP, and PVP-K, Glide), polyvinyl ethers, starch, polysaccharides, polyethyleneimines, derivatized with ethylene oxide and propylene oxide, and the like, or undivatized. Furthermore, the binder can be added or be in dispersion or latex form.For example, the polymeric binder can be a latex of acrylate or methacrylate copolymers (such as NeoCryl® materials from NSM Neoresins, the AC and AS polymers from Alberdingk-Boley) or a water-dispersible polyurethane (such as ABU from Alberdingk-Boley) or polyester (such as AQ polymers from Eastman Chemical). Polymers such as those listed above, variations, and related materials that can be used as binders in aqueous coatings are included in BASF's Joncryl® polymers, DSM Neoresins' NeoCryl materials, and Alberdingk-Boley's AC and AS polymers.

[0046] Various additives can also be used to control or adjust the pH of the aqueous coating compositions described here. Examples of suitable pH regulators include various amines, such as diethanolamine and triethanolamine, as well as various hydroxide reagents. A hydroxide reagent is a reagent containing an OH group. - The ion comprises, for example, a salt with a hydroxide counterion. Examples include sodium hydroxide, potassium hydroxide, lithium hydroxide, ammonium hydroxide, and tetramethylammonium hydroxide. Other hydroxide salts, as well as mixtures of hydroxide reagents, can also be used. Furthermore, other alkaline reagents containing OH can be used. - To generate ions in an aqueous medium. Examples include carbonates, such as sodium carbonate, bicarbonates, such as sodium bicarbonate, and alkoxides, such as sodium methoxide and sodium ethoxide. Buffers can also be added.

[0047] In a group of embodiments, it has been found that readily dispersible modified carbon blacks can be produced by surface treatment of the untreated carbon black with sulfanilic acid using diazonium chemistry, resulting in a modified carbon black containing the benzenesulfonic acid group: Benzenesulfonic acid salt, which is chemically bonded to soot (not to scale)

[0048] In a second group of embodiments, para-aminobenzoic acid is used to treat soots using diazonium chemistry to obtain a modified soot with a benzoic acid group: Benzoic acid salt, which is chemically bound to soot (not to scale)

[0049] These groups can be helpful in making the modified carbon black dispersible, and, as shown below, many of these treated carbon blacks can be stirred into coatings without the use of high energy or grinding media. Although higher amounts of treatment agent are used to improve the dispersibility of the carbon black, it has been shown that a reduced concentration of treatment results in a pigment that provides a stirred-in liquid coating, which dries to a coating with excellent coverage and color tones. It has also been found that, contrary to prior art assumptions, additional dispersant can have a detrimental effect on the dispersibility of some treated carbon blacks. As used here, a "stirred-in" or "stirred-in" carbon black is a modified carbon black that does not require pellet milling to be stably dispersed in an aqueous support.For example, very specific modified carbon blacks have an STSA of less than 300 m. 2 / g and a treatment concentration of less than 3.5, less than 3.0, less than 2.5 or less than 2.0 or 2.0 µmol / m³ 2 It has been shown that excellent coverage and color are provided by the "stirred-in" liquid coatings. Surprisingly, a treated carbon black with a low treatment concentration (e.g., less than 3.5 µmol / m²) can therefore be treated. 2) to form a stable aqueous dispersion when produced using a low-energy mixing process, resulting in a coating with high opacity and color. Contrary to conventional knowledge, these results can be achieved with low concentrations of the dispersant. For example, relative to the amount of carbon black in a liquid coating, the dispersant concentration can be less than 5.0, less than 3.0, less than 2.4, less than 2.0, less than 1.8, less than 1.5, less than 1.0, less than 0.7, and less than 0.5, 0.5, 0.2, or 0.2 mg of dispersant per square meter of carbon black surface area (STSA). In the same or other embodiments, the dispersant concentration can be greater than 0.01, 0.1, 0.2, or 0.5 mg of dispersant per square meter of carbon black surface area.Specific dispersant ranges can depend, for example, on the treatment concentration of the modified carbon black being dispersed. These dispersant ranges can be, for example, 0.1 to 3.5, 0.1 to 3.0, 0.1 to 2.5, 0.1 to 2.0, 0.1 to 1.5, 0.1 to 1.0, 0.1 to 0.7, and 0.1 to 0.5 mg of dispersant per square meter of carbon black surface. It has been found that one embodiment, in which the modified carbon black is treated with an organic treatment quantity of approximately 1.84 µmol / m², 2The modified carbon black, when treated, requires a minimal amount of dispersant. For example, in this embodiment, the amount of dispersant used to produce an aqueous granulate with 40 wt% modified carbon black can range from 0.1 to 1.0, 0.1 to 0.7, or 0.1 to 0.5 mg of dispersant per square meter of carbon black surface. When applied to an aqueous coating dispersion (1–5% modified carbon black), the granulate exhibits low viscosity, excellent opacity, good color depth, and good color tones. It is surprising that modified carbon blacks also exhibit these properties at higher treatment concentrations, e.g., 3.5 µmol / m³. 2 or more, actually requiring a larger amount of dispersant to achieve this level of coverage and color.

[0050] In a number of embodiments, it was found that a dispersion with a specific combination of a carbon black with a low treatment concentration and a liquid carrier with a low dispersant concentration can provide dispersions with properties as good as or better than dispersions produced using higher treatment concentrations or higher dispersant concentrations. For example, in one embodiment, the treatment concentration can be reduced to less than 3.5 µmol / m³. 2 The concentration of the dispersant can be limited to less than 2.4 mg per square meter of carbon black. In a further embodiment, the treatment concentration can be reduced to less than 3.0 µmol / m². 2The dispersant concentration can be limited to less than 2.4 mg per square meter of carbon black. In another embodiment, the treatment concentration can be reduced to less than 1.84 µmol / m². 2 The concentration of the dispersant can be limited to less than 1.7 mg per square meter of carbon black. In a further embodiment, the treatment concentration can be reduced to less than 3.0 mmol / m². 2 with a dispersant concentration of less than 1.0 mg per square meter of carbon black. In each of these embodiments with the limitations regarding the treatment concentration and dispersant concentrations, if the treatment concentration is in the unit µmol / m² 2 The concentration of dispersant is added in the unit mg of dispersant per square meter of soot, the sum being, for example, 2.0, 2.5, 3.0 or 3.5 or more. Evaluation procedures for aqueous coatings

[0051] To evaluate the use of carbon black regrind in the manufacture of aqueous coatings, the following procedure, referred to here as "Evaluation Procedure A for Aqueous Coatings," can be used to produce a film that is tested for properties such as color, hue, and opacity. The regrind to be evaluated is mixed with a 200 g ready-to-use dispersion containing the components and quantities specified in the table below, in order to achieve a carbon black concentration of 1 wt.% in the finished liquid coating. When cured, this composition results in a hardened coating with a carbon black content of approximately 3 wt.%. If one of the substrate components is unavailable, it can be replaced by a similar material known to a person skilled in the art. For example, Neocryl A-6085 can be replaced by another anionic acrylic styrene copolymer latex resin.The carbon black regrind is stirred into the acrylic latex coating carrier from Table 12 using a Stir-Pak® Heavy Duty laboratory mixer with a propeller-type stainless steel blade. The mixer is operated at a setting of 1.5 (500–1000 rpm) for 10 minutes. The resulting liquid dispersion is then applied to an opacity chart or stainless steel substrate of a selected thickness and cured to provide a pigmented coating, which can then be evaluated for optical properties such as color depth (L*), blue / yellow tint (b*), red / green tint (a*), and opacity. Aqueous acrylic topcoat for evaluation method A for aqueous coatings Neocryl A-6085 80,0 Water 8,4 Sodium nitrite (25%) 1,2 Dehydran 1293 0,4 Surfynol 104 DPM 0,4 BYK 346 0,1 Dipropylene glycol methyl ether 2,4 Propylene glygol n-butyl ether 4,8 Dipropylene glycol n-butyl ether 2,4 sum 100,0 % solids 32,7 Examples

[0052] To evaluate the properties of coatings produced using the modified stir-in carbon blacks described here, a series of coatings were produced using the same untreated carbon black with varying levels of organic treatment. The stir-in coatings were compared to coatings produced using the same untreated carbon black and liquid support, but using a conventional ball milling process. Example 1

[0053] An unmodified carbon black (Regal 330R) was treated with varying amounts of sulfanilic acid using conventional diazonium chemistry to obtain treated carbon blacks with treatment concentrations of 1.925 (sample 1), 2.2 (sample 2), 3.3 (sample 3) and 4.4 µmol / m³. 2 (Sample 4) to be produced. Regal 330R soot has an STSA of 85.5 m 2 / g, a DBP structure of 65 ml / 100 g, and an average primary particle size of 25 nm. The modified carbon black samples were stirred into the acrylic latex coating carrier from Table 1 using an overhead laboratory paddle mixer at 500 rpm to achieve a carbon black concentration of 1 wt% in the liquid coating. This resulted in a finished cured coating with approximately 3 wt% carbon black. For a 200 g sample, the energy required for mixing was less than 40 watts, and the dry modified carbon black was dispersed in less than 60 minutes. The control was unmodified Regal 330R, which was conventionally dispersed first into a granulate with a carbon black concentration of 15%. The granulate was then mixed into a liquid coating with 1 wt% carbon black.-% carbon black was applied using the same materials as in the experimental sample, except that a dispersant (PETROLITE D-1038) was added to achieve a concentration of 1.47 mg per square meter of carbon black surface. This contrasts with the value of 0.35 mg dispersant per square meter of carbon black surface as specified in experimental samples 1-4. Each of the samples was drawn onto an opacity chart using a squeegee at a wet film thickness of 0.0254 mm. Each of the films dried to a film thickness of approximately 0.0082 mm. Copies of photographs of these films are in the . Fig. 1 provided. As can be clearly seen from these photographs, the opacity of the material stirred in with low energy corresponds to the treatment concentrations at 1.925 and 2.2 µmol / m². 2 of the ball-milled Regal 330R. Samples with higher treatment concentrations (3.3 and 4.4 µmol / m³). 2However, they showed poor coverage. Fig. Figure 2 shows a film produced from a coating using stirred Regal 330R, as in samples 1-4, without ball milling. This example demonstrates poor coverage, highlighting the importance of modified carbon blacks, as described here, for achieving good coverage when a stir-in method is used. The experiments thus show that a low-energy stirred-in carbon black with a relatively low concentration of dispersant can replace a high-energy ball-milled carbon black with a high concentration of dispersant, which must be incorporated as milled material in the finished coating. Table 1 Components function Percentage (wt%) Neocryl A-6085 resin 32,0 Water carrier 56,4 Sodium nitrite (25%) Rust inhibitor 1,2 Dehydran 1293 Defoamer and vent 0,4 Surfynol 104 DPM Defoamer, wetting agent 0,4 BYK 346 wetting agent 0,1 Dipropylene glycol methyl ether Coalescent agent 2,4 Propylene glygol n-butyl ether Coalescent agent 4,8 Dipropylene glycol n-butyl ether Coalescent agent 2,4 Example 2

[0054] In a further series of experiments, milled materials containing the modified carbon black of sample 1 (1.925 µmol / m³) were tested. 2) with various dispersant concentrations, including 0.35 mg dispersant (PETROLITE D-1038) per square meter of carbon black surface, 0.70 mg dispersant per square meter of carbon black surface, 1.05 mg dispersant per square meter of carbon black surface, and 1.47 mg dispersant per square meter of carbon black surface. These regrinds were coated using the composition shown in Table 1 to provide a liquid coating. Fig. 2A, Fig. 2B and Fig. Figure 2C shows graphical results comparing the L* (color depth), b* (hue), and opacity of the liquid coatings with a conventional Regal 330R coating containing 1.47 mg of dispersant (PETROLITE D-1038) per square meter of the carbon black surface. As shown in Fig.Figure 3 shows that the L* color performance on a steel substrate is significantly improved compared to the color performance obtained using the control (L* value of approximately 5). Without dispersant, sample 1 provides an L* value of less than 3, and with 0.35 mg of dispersant per square meter of the carbon black surface, sample 1 provides an L* value of 3.3. With 0.70 mg of dispersant per square meter of the carbon black surface, sample 1 provides an L* value of 3.5, while the conventional coating with a dispersant concentration of 1.47 mg of dispersant per square meter of the carbon black surface exhibits an L* value of 4.9.

[0055] Fig.Figure 4 graphically shows the opacity of all samples. The coatings were applied to a thickness of 0.0254 mm and dried. The opacity was evaluated using the BYK opacity diagram #2813. The ball-milled control sample had a dispersant concentration of 1.47 mg / m². 2 and all experimental samples showed an opacity of 1. This illustrates that the experimental samples can exhibit the same opacity as aqueous coatings made from a conventional carbon black with a higher dispersion agent concentration, which has been ground with high energy.

[0056] Fig. Figure 5 provides graphical data showing the bluish tint values ​​for the experimental samples and the control. The conventional bead-milled material has a density of 1.47 mg / m³. 2The dispersant provided a b* value of approximately 0.0. Except in the case where no dispersant was present, all stirred liquid coatings resulted in coatings with negative (preferred) color tones of approximately -0.6. This demonstrates the excellent bluish tint of the stirred coatings produced from the modified carbon black systems described herein. Example 3

[0057] In a further experiment, a regrind (S) was produced using modified carbon blacks and the methods described here and was compared with a regrind (M) produced using conventional carbon blacks. Regrind S was mixed with 35.5 wt% carbon black using the composition according to Table 2 at 0.35 mg / m³. 2 A quantity of dispersant was prepared. Sample S was prepared using 92 grams of Regal 330R, which has a concentration of 1,925 µmol / m³. 2Sample M was treated with sulfanilic acid. Sample M was prepared using untreated Regal 330R. Sample S was stirred with a vertical blade stirrer at 500 rpm (1.05 m / s peak speed) and 40 watts. Sample M was initially intended to undergo a premixing step using a high-speed mixer (10 m / s peak speed), followed by a milling step in an Eiger mill. However, after the premixing step, the paste was found to be too thick to pass through the mill. Table 2 Components Mass (g) Water 128,2 AMP-95 5,3 Dehydran 1293 6 Petrolite D1038 27,6 soot 92

[0058] The results of each sample are in the Fig. 6A and Fig.6B is shown. As clearly illustrated, sample S (6A) produced a pourable, well-dispersed regrind. Its viscosity was measured at 530 mPa·s (cP) using the Brookfield viscometer and the procedure described here. However, sample M (6B) resulted in a thick paste that was not pourable and unsuitable for use as regrind.

[0059] Another modified carbon black (sample 5) was obtained by treating Black Pearls 800 (Cabot Corporation) with a surface concentration of 2.90 µmol / m². 2(STSA) Sulfanilic acid was prepared. To prepare a regrind with incorporated carbon black, Sample 5, water, base (AMP-95), defoamer (Dehydran 1293), and dispersant (Petrolite D-1038) were mixed using a Dispermat® (40 mm diameter Cowles blade) at 500 rpm (peak speed of 1.05 m / s) for 1–2 min (see Table 3). Sample 5 was added while stirring for 60 seconds. The mixing speed was then increased to 1000 rpm (peak speed 2.10 m / s), and mixing was continued at 1000 rpm for 30 min. The regrind contained 17.6 wt% carbon black, and the active dispersant / carbon black ratio was approximately 3 wt% or 0.157 mg of active dispersant per square meter of carbon black surface. Table 3 Starting material % by weight Water 73,1 AMP-95 1,0 Dehydran 1293 (10% active) 3,0 Petrolite D-1038 (10% active) 5,3 Sample 5 CB 17,6 In total 100,0

[0060] To produce a carbon black regrind using conventional carbon black of the same morphology as sample 5 but without surface treatment, the composition according to Table 4 was used. Water, base, defoamer, and dispersant were mixed with a Dispermat® at 500 rpm for 1–2 minutes. Then, conventional carbon black (Black Pearls 800 (STSA 191 m)) was added. 2 / g), Example 6) was added while stirring. After all the carbon black had been added, the mixing speed was increased to 4000 rpm (peak speed of 8.4 m / s) and the components were mixed for approximately 5 minutes. The premix was then passed through a horizontal ball mill for approximately 20 minutes. The milled material contained 17.6% carbon black, identical to the milled material with carbon black mixed in. However, the active dispersant / carbon black ratio had to be significantly higher for conventional carbon black (approximately 25% wt / wt or 1.3 mg dispersant per square meter of carbon black surface) to disperse and obtain a stable milled material. Table 4 Starting material % by weight Water 34,4 AMP-95 1,0 Dehydran 1293 (10% active) 3,0 Petrolite D-1038 (10% active) 44,0 Sample 6 17,6 In total 100,0

[0061] The carbon black regrind (from samples 5 and 6) was then combined to form both aqueous acrylic and alkyd resins. For aqueous acrylic coatings, the acrylic topcoat masterbatch composition according to Table 5 was used. To produce a finished black acrylic coating, 5.2 g of carbon black regrind was slowly added to 94.8 g of acrylic topcoat with vigorous stirring, according to the composition in Table 6, and mixing was continued for 15 minutes. Similarly, for the aqueous alkyd coatings, the alkyd topcoat was prepared according to the alkyd masterbatch composition in Table 7, and the finished alkyd coating was prepared according to the composition in Table 8. Table 5 Starting material % by weight Neocryl A-6085 (40% solid acrylic latex) 80.0 Water 8.4 Sodium nitrite (25% water) 1.2 Dehydran 1293 (10% active) 0.4 Surfynol 104 DPM (wetting agent) 0.1 BYK346 0.1 Dipropylene glycol methyl ether 2.4 Propylene glycol-n-butyl ether 4.8 Dipropylene glycol n-butyl ether 2.4 In total 100.0 Table 6 Starting material % by weight Acrylic coating masterbatch 94.8 Soot mill 5.2 In total 100.0 Table 7 Starting material Quantity (g) Uradil az-760 (53% solid) 88.8 Water 5.4 Dehydran 1293 (10% active) 0.5 Surfynol 104 DPM 0.7 BYK 346 0.2 Dipropylene glycol methyl ether 1.8 Propylene glycol-n-butyl ether 2.6 In total 100.0

[0062] Another modified carbon black (sample 7) was produced using the same procedures as above, by combining ELFTEX® 320 (STSA 62 m 2 / g) (Cabot Corporation) to a surface concentration of 2.1 µmol / m² 2 The sample was treated with sulfanilic acid. To prepare a stirred-in carbon black regrind, Sample 7, water, base (A P-95), defoamer (Dehydran 1293), and dispersant (Petrolite D-1038) were mixed using a Dispermat® (40 mm diameter Cowles blade) at 500 rpm (peak speed of 1.05 m / s) for 1–2 min (see Table 3). Sample 7 was added while stirring. The mixing speed was then increased to 1000 rpm for 30 min, and mixing was continued at 1000 rpm for 30 min. The regrind contained 17.6 wt% carbon black, and the active dispersant / carbon black ratio was approximately 3 wt / wt or 0.5 mg dispersant per square meter of carbon black. Results

[0063] A tinting study was conducted to evaluate the difference between samples 5 and 6. For the tinting study, a white tint base containing TiO2 was prepared, and a black topcoat was subsequently added to achieve a carbon black to TiO2 solids ratio of 1.3 wt%.

[0064] The resulting coatings were drawn onto steel plates using a 0.0762 mm (3 mil) drawing bar (~0.0254 mm (1 mil) dry film thickness) for color measurement. Color measurement was performed using a Hunter Labscan XE spectrophotometer from HunterLab Inc. For opacity measurement, the coatings were drawn down on an opacity chart using a 0.0762 mm (3 mil) drawing bar (~0.0254 mm (1 mil) dry film thickness). The ratio of optical density in the white portion of the chart to optical density in the black portion was calculated to determine the opacity of each sample. For the acrylic coatings, the plates were exposed for 20 min and then baked at 70 °C for 30 min before measurements were taken. The alkyd coatings were air-dried at room temperature for 7 days before measurements were taken.

[0065] Fig.Figure 2 shows the opacity of the acrylic coatings with a regrind made from conventional, untreated carbon black, which was produced using only a high-speed mixer according to the composition shown in Table 1. It is clear that the untreated carbon black did not disperse properly with the high-speed mixer, as large clumps of carbon black were observed. Consequently, the film did not achieve its full color potential. When conventional treatment concentrations (greater than 3.3 µmol / m²) were used, the opacity was significantly reduced. 2 When used, the treated carbon blacks were easily dispersible in water. However, when the liquid coatings dried, the conventionally treated carbon black with excessively hydrophilic groups was incompatible with the aqueous resin, resulting in large areas of the film lacking carbon black and thus degrading the color performance, as shown in Fig. The last plate is shown. Only when the treatment concentration is below 3.3 µmol / m³ 2The treated carbon black was easily dispersible in water and compatible with aqueous coating resins after the coating had dried. Consequently, a dark black film with excellent opacity was obtained, as shown in Fig. 1. First two records shown.

[0066] The Fig. 7A and Fig. Figure 7B shows the comparison of the color performance of Sample 5 and Black Pearls 800, which have identical morphology with respect to the solid (A) and tint (B) compositions in the acrylic coating. It is clear that Sample 5 provides a lower L* with respect to both the solid and tint compositions compared to conventional carbon black (Black Pearls 800), indicating greater color depth in the solid composition and greater color strength in the tint composition. The same advantage was observed when Sample 5 was introduced into alkyd coatings, as in Fig. 7C and Fig.7D representation. It was also observed that Sample 5, in solid-color compositions, resulted in coatings with a bluish tint (low b-value), which is often indicative of a finer degree of carbon black dispersion. Furthermore, these color performance benefits for Sample 5 were achieved only when using a Dispermat® mixer to produce the carbon black regrind without a grinding step. Additionally, Sample 5 required only about 0.157 mg of active dispersant per square meter of carbon black surface, whereas conventional carbon black requires 1.3 mg of active dispersant per square meter of carbon black surface. The use of an excess of dispersant not only contributes to significant costs for coating or regrind manufacturers but also makes the surface of finished coatings more hydrophilic due to the migration of dispersant to the coating surface, thereby degrading the coating's durability and weather resistance.

[0067] The same information regarding full tone and hue for sample 2 and the untreated Regal 330R is in the Fig. Samples 8A to 8D were provided. As explained above for Example 5, experimental sample 2 provided a lower L* compared to conventional carbon black (Regal 330R), suggesting greater color depth in the solid color composition and greater color strength in the tint composition. Sample 2 also provided similar improvements to the alkyd coatings.

[0068] The Fig. 9A-9D provide corresponding values ​​for sample 7 and the untreated Elftex 320 carbon black. Sample 7 provided a lower L* compared to conventional carbon black (Elftex 320), suggesting greater color depth of the solid color composition and greater color strength of the tint composition. Sample 7 also provided similar improvements to the alkyd coatings as in the Fig.9C and Fig. 9D was shown. Therefore, for each of the samples 5, 2, and 7, it was demonstrated that these provided improved color depth and hue compared to the untreated carbon blacks from which each sample was produced. This was also true for low concentrations of the dispersant and in two different coating types: acrylic and alkyd coatings.

[0069] To verify the degree of dispersion of each of the soot samples, a cross-sectional scanning electron microscope (TEM) examination was performed. The coatings on the opacity diagrams were microtomized using a PowerTome PC (Boeckeler), and thin slices were photographed on copper grids for TEM examination using a JEM1200 (JEOL) at an accelerating voltage of 80,000 V. Fig. 10A and Fig. The magnification for 10B is 2000x. Fig.Figure 10A shows the distribution of sample 5 in the acrylic coating. It was found that these fine carbon black particles were well dispersed in the coating polymer matrix; their size appeared to be close to the basic aggregate size of 100–200 nm. This demonstrates that the carbon black regrind containing sample 5, produced using only a Dispermat®, was very well deagglomerated, confirming that the stirring-mixing conditions were sufficient to disperse sample 5 to almost the aggregate level. Fig. Figure 10B shows the distribution of Black Pearls 800 with identical morphology to that of sample 5 in the acrylic coating. The Black Pearls 800 regrind was first obtained by a premixing step with a Dispermat®, followed by a grinding step using a horizontal mill. As shown in Figure 10B, the distribution of Black Pearls 800 with identical morphology to that of sample 5 in the acrylic coating was first obtained by a premixing step with a Dispermat®, followed by a grinding step using a horizontal mill. Fig.As can be seen in 10B, even with horizontal milling and a much higher amount of dispersant (1.3 mg versus 0.157 mg dispersant per square meter of carbon black surface), deagglomeration of the conventional carbon black to the basic aggregate size was difficult to achieve, and a certain concentration of particle agglomeration remained in the finished coating. The dispersant used for sample 5 and for Black Pearls 800 was the same.

[0070] To demonstrate dispersibility at higher concentrations, a carbon black regrind containing 30% of Sample 5 was prepared without a dispersant using a Dispermat® at 1000 rpm for 30 minutes. The resulting regrind was a fluid. In another example, Sample 2 was used to prepare a stirred regrind containing 35.5% carbon black in the presence of 3% dispersant using a Dispermat® at 1000 rpm for 30 minutes. The resulting regrind had a viscosity of approximately 600 cP at low shear and exhibited shear-thinning behavior, as shown in Fig.Figure 11 shows that, in contrast, the untreated Regal 330R, with identical morphology to Sample 2, required a horizontal mill to produce a milled product. The maximum carbon black content in the milled product was approximately 20%; above this value, the milled product was too viscous to pass through the horizontal mill. At this solids content (> 20 wt%), the viscosity of the premix was similar to the viscosity of the milled product (without premix) of Sample 2, which had a solids content of 35.5%, as shown in Figure 11. Fig. 11 shown. The higher carbon black regrind concentration, made possible by the addition of carbon black, as revealed here, allows for greater flexibility in the composition of the coatings and also enables regrind manufacturers to ship less water in their products.

[0071] To illustrate the importance of selecting the correct carbon black treatment concentration and dispersant concentration, a series of regrind samples with very similar compositions, but with slight variations in treatment and / or dispersant concentration, were produced. Unless otherwise specified, the dispersions produced from the modified carbon blacks described herein were prepared using the following procedure. The modified carbon blacks were dispersed using a Dispermat® CV3+ mixer (VMA-GETZMANN GmbH) with a 40 mm Cowles paddle and a stainless steel mixing vessel. The geometry was configured as recommended by the manufacturer. The following example provides details for the production of a 200 g dispersion from 30 wt% modified carbon black and 0.185 mg dispersant per square meter of carbon black surface area (STSA).The specific modified carbon black and dispersant concentrations were adjusted in the subsequent series to produce the milled products provided in Table 9. The sample milled products contained 40 wt% modified carbon black, except for samples 8A, 8B, 13, and 14 (30 wt%) and samples 15 and 16 (10 wt%), as these samples were not dispersed with 40% of the dispersant. Samples 8A through 14 were milled using Regal® 660R (STSA of 121 m). 2 / g and DBP of 65) as the base carbon black produced. Sample 15 showed an STSA of 370 m 2 / g before treatment and a DBP structure of 100 cm 3 / g. Sample 16 showed an STSA of 325 m 2 / g and a DBP structure of 100 cm 3 / g. The base carbon blacks of samples 15 and 16 were prepared according to the process described in U.S. Patent No. RE28,974 and were treated with sulfanilic acid as described in U.S. Patent No. 5,707,432. These two patents are incorporated herein by reference.

[0072] 111.6 g of water (132 g for 8A, 8B, 13, and 14; 169.5 g for 15 and 16), 6.0 g of Dehydran® 1293 (defoamer), 0.5 g of AMP-95 (pH adjuster), and 1.94 g of Disperbyk 192 dispersant (1.45 g for 8A, 8B, 13, and 14; 4.0 g for 15 and 16) were introduced into a 600 ml stainless steel beaker with an inner diameter of 90 mm. The beaker was placed on the Dispermat, and the 40 mm paddle was adjusted to a height of 15 mm to ensure the liquid completely covered the paddle. The components were then mixed together for one to two minutes at 1000 rpm. 80 g (60 g for 8 A, 8 B, 13 and 14) of the dry modified carbon black powder, treated with sulfanilic acid, were weighed into a separate container and slowly added to the aqueous mixture over 60 seconds. A visual inspection was carried out to confirm that all the modified carbon black was wetted.The Cowles paddle was then set to a height of 20 mm and the speed to 2000 rpm, corresponding to a paddle tip velocity of 4.2 m / s. The mixer was operated at 2000 rpm for 30 minutes to produce the aqueous dispersion of the modified carbon black. For sample 8B, the mixer was operated at 4000 rpm instead of 2000 rpm for the same 30-minute period.

[0073] The treatment concentration, dispersant concentration, and particle size distribution for each sample are provided in Table 9. Experiments were conducted to process additional milled material samples using modified carbon blacks with treatment concentrations of 4, 5, and 6 µmol / m³. 2 to produce, but the samples were not further investigated. In addition, a modified carbon black with a treatment concentration of 1 µmol / m³ was found. 2The sample containing 0.2 mg of dispersant (Disperbyk 192) could not be converted into a usable 30% carbon black dispersion by weight, as it was not wetted. Particle size distributions were determined using a Horiba Scientific LA-950V2 particle size analyzer. For particle size determination, each dispersion was diluted with water at pH 10.5 to a solids concentration of approximately 0.1 wt%. Volume-averaged agglomerate size distribution curves were generated by performing each sample twice. Table 9 presents the mean value, mode, D10, and D90 of the particle size distribution for each dispersion. The D90, in particular, is considered a good indicator of how well a carbon black is dispersed and is provided on a volume-averaged basis. The surface area value used to determine the treatment concentration and dispersant concentration is the STSA of the unmodified carbon black.Each analysis was performed in duplicate. Sample 13 showed a bimodal distribution with a small second mode at approximately 2 µm, and sample 16 showed a bimodal distribution with two modes at 1 µm and 100 µm. Samples 15 and 16 were not dispersible at 30 wt%, and large particles were observed at a dispersion of 10 wt%. This means that these carbon blacks are not suitable for use in blended milled materials with more than 30% carbon black, and that carbon blacks with a large surface area (STSA) greater than 300 m² are not recommended. 2 / g are unsuitable for this purpose. Table 9 Sample ID Treatment concentration µmol / m³ 2 Active dispersant concentration mg / m³ 2 D50 (average) µm Whiteµm D10µm D90 µm 8A Row 1 1,0 2,4 0,182 0,185 0,102 0,307 8A Row 2 1,0 2,4 0,183 0,185 0,102 0,309 8B Row 1 1,0 2,4 0,103 0,106 0,070 0,153 8B Row 2 1,0 2,4 0,103 0,106 0,070 0,153 9 Row 1 1,84 0,2 0,195 0,185 0,100 0,446 9 Row 2 1,84 0,2 0,195 0,185 0,100 0,425 10 Row 1 1,84 0,5 0,118 0,122 0,077 0,181 10 Row 2 1,84 0,5 0,115 0,122 0,075 0,177 11 Row 1 1,84 1,7 0,105 0,107 0,071 0,158 11 Row 2 1,84 1,7 0,105 0,107 0,071 0,158 12 Row 1 1,84 2,4 0,102 0,094 0,070 0,152 12 Row 2 1,84 2,4 0,102 0,094 0,070 0,151 13 Row 1 3,5 0,2 0,125 0,122 0,076 0,732 13 Row 2 3,5 0,2 0,125 0,122 0,076 0,788 14 Row 1 3,5 2,4 0,103 0,107 0,070 0,156 14 Row 2 3,5 2,4 0,104 0,107 0,070 0,156 15 Row 1 2,2 0,5 0,794 0,819 0,362 1,796 15 Row 2 2,2 0,5 0,796 0,819 0,362 1,800 16 Row 1 1,6 0,6 28,234 1,067 0,920 115,572 16 Row 2 1,6 0,6 27,903 1,066 0,914 115,277

[0074] Table 10 below provides additional values ​​for the same dispersions prepared in Table 9. In addition to the D90, the table provides viscosity values ​​for each of the samples for each of the milled materials for which viscosity could be tested. Each sample was tested using the Brookfield DV-II+ viscometer and the procedure described herein. Each sample was evaluated, and the viscosities were recorded at 10, 20, 50, and 100 min. There was no direct correlation between dispersant concentration and relative viscosity. Table 10 Sample No. . % wt. soot Treatment concentration µmol / m³ 2 Active dispersant concentration mg / m³ 2 D90 particle size µm Viscosity (mPa·s = cP) 10 rpm 20 rpm 50 rpm 100 rpm 8B 30 1 2,4 0,153 3484 2232 1302 843 9 40 1,84 0,2 0,436 9263 4861 2083 1141 10 40 1,84 0,5 0,179 361 311 253 202 11 40 1,84 1,7 0,158 1069 744 454 315 12 40 1,84 2,4 0,152 6386 3732 1885 1141 13 30 3,5 0,2 0,760 298 174 98,0 62 14 30 3,5 2,4 0,156 4216 1972 856 484

[0075] The samples were lacquered to determine their opacity, color, and tint properties when applied as a finished coating. Color depth (L*), blue / yellow tint (b*), and red / green tint (a*) were measured for a wet film thickness (WTF) of 0.0762 mm using a Hunter Lab Scan XE spectrophotometer and are reported in Table 11 below. Opacity was evaluated for a wet film thickness of 0.0762 mm (WTF) using a BYK Opacity Chart #2813 with half black and half white. Coating opacity was determined using an X-rite® Exact Densitometer and is also reported in Table 11. Due to their inability to disperse, samples 15 and 16 were unsuitable for use in an aqueous coating granulate, and therefore no color and opacity values ​​are reported for these samples.The samples exhibiting good opacity (> 0.99) and low viscosity (Table 10) were those with a relatively low combination of treatment concentration and dispersant quantity in the milled material. Conversely, the samples with high treatment concentrations and / or high concentrations of dispersant were not optimal for at least one of the opacity, color, viscosity, or particle size. In summary, these data show that some of the best results are indeed achieved in dispersions with a relatively low treatment concentration, for example, less than 3 µmol / m. 2 , as well as containing a low concentration of dispersant, e.g., 2.4 mg per square meter of the carbon black surface or less. Thus, an effective stirred-in regrind or liquid coating dispersion can be produced with a low concentration of organic treatment and reduced concentrations of dispersant. Table 11 sample Dispersant wt.% L* a* b* Opacity @ WFT of 0.0762 mm 8A 29 2,55 0,37 0,51 0,99 8B 29 2,72 0,41 0,64 1,00 9 2,5 2,13 0,28 0,18 0,97 10 6,0 N / A N / A N / A 1,00 11 20 2,11 0,26 0,16 1,00 12 29 2,08 0,27 0,21 0,99 13 2,5 1,79 0,1 -0,01 0,95 14 29 1,88 0,13 0,03 0,98

[0076] All definitions, as previously defined and used herein, are to be understood as including dictionary definitions, definitions in documents referenced, and / or the ordinary meaning of the defined terms.

[0077] The indefinite articles “ein” and “eine”, as used here in the description and in the claims, are to be understood as “at least one”, unless clearly stated otherwise.

[0078] The expression "and / or," as used here in the description and in the claims, should be understood to mean that "either one or both" of the elements are combined, i.e., elements that are present together in some cases and separately in other cases. Other elements may be present, besides those specifically identified by the "and / or" clause, whether related or unrelated to the specifically named elements, unless otherwise stated.

[0079] All references, patents and patent applications and publications cited or mentioned in this application are included in their entirety by reference.

Claims

[1] Carbon black regrind dispersion, comprising: an aqueous solvent comprising more than 90 wt% water; 30 to less than 60 wt.% of a modified carbon black, wherein the modified carbon black has an STSA between 20 and 300 m 2 / g, measured before treatment, the modified carbon black is modified with a treatment agent containing an organic group and an ionic or ionizable group at a treatment agent concentration between 1.0 and 3.0 µmol / m 2 exhibits; a dispersant concentration of less than 2.4 mg per square meter of soot surface as measured by STSA before treatment; and where less than 10 vol.-% of the soot distributed in the ground material has a particle size of more than 0.5 µm. [2] Carbon black regrind dispersion, comprising: an aqueous solvent comprising at least 90% by weight water; more than 30 to less than 60 wt% modified carbon black, wherein the modified carbon black is combined with an organic treatment compound having a treatment concentration of between 1 and 3.0 µmol / m³ 2 is treated, the organic treatment compound comprises both an aryl group and an ionic or ionizable group, the modified carbon black is made from untreated carbon black with an STSA of more than 20 m 2 / g and less than 300 m 2 / g is produced; 2.4 mg of dispersant per square meter of soot surface or less; and the carbon black regrind dispersion remains stably dispersed after one week at 52 °C. [3] Carbon black regrind dispersion comprising 30 to less than 60% of a modified carbon black and less than 2.4 mg dispersant per square meter of carbon black surface, wherein the modified carbon black is combined with a treatment agent comprising an organic group and an ionic or ionizable group at a concentration of 2.0 µmol / m² 2 or less treated, the milled material comprises an aqueous solvent comprising at least 90% water, and wherein the sum of the treatment concentration is in µmol / m 2 and the dispersant concentration in mg / m³ 2 2.5 or more. [4] Ground material dispersion according to one of claims 1, 2 or 3, wherein, when tested using the evaluation method A for aqueous coatings, the resulting hardened coating has an opacity of 0.98 or more at a wet film thickness of approximately 0.076 mm on stainless steel. [5] Ground material dispersion of the preceding claims, wherein the modified carbon black has an average primary particle size of 15 - 50 nm. [6] Ground material dispersion according to one of the preceding claims, wherein the treatment agent comprises an aryl group. [7] Ground material dispersion according to any of the preceding claims, wherein the treatment agent comprises a sulfonic acid group or salts thereof, a benzoic acid group or salts thereof, a carboxylic acid group or salts thereof or a phosphonic acid group or salts thereof. [8] Ground material dispersion according to one of the preceding claims, wherein the carbon black ground material contains a non-ionic dispersing agent. [9] Aqueous coating dispersion produced from the ground material according to any of the preceding claims, wherein the aqueous coating dispersion comprises an aqueous alkyd or acrylic resin. [10] Ground material dispersion according to one of claims 1-8, wherein the treatment agent is directly bound to the soot. [11] Aqueous coating produced by coating the ground material dispersion according to one of the preceding claims to a concentration of the modified carbon black of between 0.01 and 5 wt.%. [12] Ground material dispersion according to one of claims 1-8 and 10, wherein the dispersion has a Brookfield viscosity of less than 1.1 Pa·s (1100 cP) at 10 rpm and 25 °C. [13] Method for producing an aqueous dispersion of ground material, the method comprising: Stirring a non-dispersed modified dry carbon black powder, which contains no grinding media, in an aqueous carrier with a concentration of 30 to less than 60 wt%, based on the final weight of the ground material, to form a carbon black regrind, wherein the modified carbon black is combined with a treatment agent in an amount between 1.0 and 3.0 µmol / m³ 2is treated, the treatment agent comprises an aryl group and an ionic or ionizable group, the aqueous carrier comprises a solvent that contains more than 90 wt% water and less than 2.4 mg dispersant per square meter of soot surface, and where less than 10 vol% of the soot distributed in the ground material has a particle size of more than 0.5 µm. [14] Method according to claim 13, wherein less than 10 vol% of the soot particles distributed in the ground material have a particle size of more than 0.4 µm. [15] Method according to claim 13, wherein the carbon black is dispersed in a concentration of 40 wt.% or more. [16] Method according to claim 13, wherein the dispersing agent is present in a concentration of less than 1.7 mg of dispersing agent per square meter of the soot surface.

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