Low-solvent paint composition, production, processing and use thereof

Abstract

The invention relates to a paint composition comprising a paint powder, an additive and a binder, wherein the paint composition has a solvent content of ≤ 10 percent by weight relative to the total mass of the paint composition and can be converted into a paint by adding solvent. The invention also relates to a method for manufacturing a paint, as well as to a paint.

Description

[0001] Low-solvent paint composition, its production, processing and use

[0002] Description

[0003] The present invention relates to a novel method for producing a paint, preferably a dispersion paint, for use in interiors and on exterior facades. The invention further relates to its processing and use. A multitude of different paints and paint compositions are known from the prior art, which are adapted to the respective tasks and application scenarios.

[0004] Paints and coatings are a well-known example. These are typically liquid to paste-like, and less frequently powdered, substances or mixtures that, when applied to surfaces, produce a coating that dries physically or hardens chemically. According to DIN 55945, a paint or coating is defined as a liquid to paste-like coating material that is primarily applied by brushing or rolling. Essential components of a paint or coating often include a binder, a colorant (pigment or soluble dye), one or more fillers, a solvent, and possibly an additive such as a thickener, dispersant, or preservative. Paints and coatings containing pigments are also known as coatings or paints. Paints and coatings are often classified according to their film-forming binders.These in turn can be primarily divided into organic and inorganic binders, resulting in the product classes varnish, glaze and oil paints; dispersion paints; lime paints; silicate paints; and liquid plasters.

[0005] A significant market share of coating materials is comprised of facade paints made from dispersion. Dispersion paints are typically viscous to thin-bodied coatings. They consist of a dispersion (usually a suspension) of solvents, binders and solvents, pigments, as well as fillers and auxiliary agents or additives. Although, in this general sense, the majority of liquid coatings (varnishes, paints) are dispersions, the term "dispersion paint" in a narrower and more colloquial sense is usually understood to mean a standard water-based wall paint. Higher-quality paints are often referred to as acrylic or synthetic resin dispersion paints.

[0006] In addition, there are similarly structured water-based wall paints on the market that primarily use vegetable oils instead of synthetic and mineral oil-based ingredients and are called natural dispersion paints.

[0007] Synthetic resin dispersion paints (also known as plastic dispersion paints, coatings, or dispersions) are wall coatings that generally consist of a dispersion of synthetic resin and water. For interior use, their quality characteristics are standardized in EN 13300, while those for exterior use are standardized in EN 1062. The main components are typically water as a solvent, synthetic resins (mostly acrylic resins) or similar plastics (e.g., polyvinyl acetate) derived from fossil monomers and / or bio-based monomers as binders, and colorants or pigments. Synthetic resin dispersion wall paints with particularly high water resistance, for exterior and facade applications as well as for damp areas inside buildings, contain a higher proportion of synthetic resin. Synthetic resin dispersion paints with decorative additives such as glitter are also referred to as latex paints.

[0008] Besides liquid synthetic resin dispersion paints, there are thixotropic (compact) coatings. Their thixotropy is intended to reduce dripping and splattering during application. These types of coatings, known as compact paints, have lost market share because most dispersion paints are now formulated to be drip-resistant (slightly gel-like) and, unlike compact paints, are much easier to apply. White dispersion paints can be tinted with full-tone paints, tinting paints, or pigment preparations. Pigment preparations are pre-dispersed, binder-free products that would not form a film if used alone. Such additives are mostly used in automatic systems and tinting systems. However, there are also a few manufacturers that offer pigment preparations for professional use. Full-tone and tinting paints are ready-to-use coatings that contain film-forming agents.Full-tone and tinting colors are typically used for manual tinting in the "do-it-yourself" sector.

[0009] Pre-tinted paints are available in hardware stores and home improvement centers. The paints are either mixed on-site using computer-controlled systems (point-of-sale tinting) or delivered pre-tinted from the factory (in-plant tinting or "factory tinting"). In some countries, such as the United States, point-of-sale tinting has become the standard and is available not only in home improvement stores but also in retail chains. A minimum order quantity is usually required, as tinting small quantities in particular demands high dosing accuracy and precise adjustment of the pigment preparations used. In principle, the same pigments can be used manually and automatically, achieving the same level of colorfastness in the resulting shades. In practice, automated dosing systems use a limited selection of color-matched and cost-effective pigments that must cover all available coating shades.The color accuracy of automatic dosing systems depends heavily on the number and type of pigments used, as well as on the color formulations stored in the mixer.

[0010] Emulsion paints typically contain preservatives and biocides to prevent bacterial growth and mold formation. Without preservatives, many paint systems would spoil in the container. Some of these substances can cause allergic reactions during application. Preservative-free emulsion paints can also be produced by adjusting the pH value to between 10.5 and 11.4; however, safety goggles should be worn during application, as the elevated pH can cause eye irritation. Paints without biocides can also be stabilized using suitable mineral additives. These are physiologically safer and are used, for example, in the production (coating) of food packaging to ensure food safety. These paints are commercially available and appropriately labeled, and are particularly recommended as wall paints for children's rooms or hospitals.Natural emulsion paints or stains are used like synthetic resin emulsion paints; however, unlike the latter, they consist exclusively or primarily of natural, non-synthetic ingredients. The formulations of natural emulsion paints are largely similar to those of other emulsion paints, except that plant oils such as linseed oil or castor oil are used as drying oils instead of synthetic resin, and pigments such as titanium dioxide are replaced by other natural pigments. Mineral pigments have the advantage over organic pigments of fading less in sunlight. Due to the raw materials, which are rarely mass-produced, natural emulsion paints are generally more expensive than synthetic resin-based paints. The evaporation of the natural oil after application of such paints produces an odor that may be perceived as pleasant or unpleasant, depending on individual perception.A disadvantage is that the natural oils used (especially linseed oil) can lead to yellowing of the paint. However, an advantage is that the formation of dust rings (for example, on picture frames) is usually less than with synthetic resin dispersions, since no static charge occurs.

[0011] For paints and coatings, there are a number of standards and test criteria designed to help users determine which paint is suitable for which application. For example, the EN 13300 standard provides a qualitative classification of wall and ceiling paints according to their intended use and binder type. The following criteria, among others, are used for differentiation: contrast ratio (opacity), gloss / reflectivity, maximum particle size, and wet scrub resistance.

[0012] The aforementioned paints are usually sold ready-to-use. They are sold, for example, through DIY stores, specialist retailers, discount stores, or via e-commerce. There are also retail outlets, especially those of larger paint manufacturers. Using the clearly defined quality criteria, customers can consciously and specifically purchase the desired paint properties.

[0013] A major disadvantage is the large volume and weight of these paints. This results in high freight costs for distribution and significant CO2 emissions during transport. Furthermore, specialist retailers, paint stores, discount stores, DIY stores, and upstream distribution centers, as well as indirectly through e-commerce, require substantial shelf and / or storage space for sales. The desire of many users to select their desired color from the widest possible palette necessitates stocking a large number of different colors in stores. This leads to a significant space requirement and thus high costs. Additionally, the storage time for some colors before they are sold is often very long, requiring the paints to contain a large quantity of biocides and preservatives to remain usable even after extended storage.Some people are allergic to some of the biocides and preservatives.

[0014] For some applications, especially in the home, this disadvantage is circumvented by using dry or powdered paints. These are based, for example, on clay, chalk, marble dust, natural pigments, casein as a binder, and possibly also fiber components, and are mixed with water immediately before application to create a brushable and / or sprayable suspension. Such paints are usually applied immediately after mixing using a brush or roller. These paints can also be applied several times.

[0015] A significant disadvantage of these paints is that their quality is sometimes considerably lower than that of ready-to-use emulsion paints, such as those from DIY stores. The difference compared to professional paints, like those used in the painting trade, is even more pronounced, and the quality of the latter is significantly better. Furthermore, it has been observed that when mixed at home, even with identical proportions of the components, the resulting colors can vary considerably. Differences in the mixing process or preparation have been identified as the cause.They can be induced, for example, by differences in energy input and mixing time, the settling time, the quality of the pigment particle separation, the quality and homogeneity of the distribution of the pigment dyes and thus the color effect, different proportions (for example, due to hygroscopic effects or stirring up the powder), and others.

[0016] It has also been observed that dry paints tend to produce dust when stirred in private households, which is undesirable for various reasons, especially if any ingredients should not be inhaled. Therefore, there is a need for a high-quality paint that can be supplied in a consistent quality, requires less storage space than currently available paints, and is easier to transport. Furthermore, such a paint should be offered to the user in a wide variety of colors.

[0017] Furthermore, the invention aims to provide a method by which a high-quality coating can be produced in consistent quality according to customer-specific requirements.

[0018] This task is solved by a color composition comprising a color powder, one or more additives, fillers and a binder, and characterized by having a solvent content (liquid medium content) < 10 mass percent based on the total mass of the color composition and being convertible into a coating material by adding liquid medium.

[0019] In the context of color compositions, water-based color compositions are often advertised as "solvent-free," even though they contain a solvent, namely water. To avoid such ambiguities, the more general term "liquid medium" is used in this invention instead of "solvent." However, whenever the term "solvent" is used, it should be understood—just like "liquid medium"—in its generally accepted sense, namely that both inorganic and organic liquids are included. The terms "liquid medium" and "solvent" are therefore used synonymously in this invention.

[0020] A liquid medium or solvent can be inorganic or organic, or a mixture of several liquids (each independently inorganic or organic) in any proportion. It can be polar to nonpolar and act as a solvent (dissolving compounds soluble in it, such as salts, additives, polymers, etc.) and / or as a medium for the formation and production of dispersions. Preferably, the liquid medium is water. In one variant, liquid media with lower polarity can be included additionally or alternatively. A paint composition as described above has the advantage of requiring comparatively little volume and is therefore easy to store and transport. It is nevertheless easily converted into a coating and is thus readily available for application as a coating.

[0021] Preferably, the paint composition has a water content of < 10% by mass, more preferably < 8% by mass, more preferably < 5% by mass, further preferably < 3% by mass, and particularly preferably < 1% by mass. This is especially preferred when water is used as the solvent (liquid medium). The weight and volume fraction of water can thus be saved during storage and transport. Since water is readily available almost everywhere in good and, in particular, known quality, it is possible to adjust the water content of the coating to a predefined target value by subsequently adding water in a targeted manner.

[0022] Preferably, the color composition is water-soluble, water-emulsifiable, or water-suspensable. Accordingly, the aforementioned liquid medium can serve as a solvent for dissolving compounds, as well as a component of slurries, for example, for the production of emulsions or suspensions.

[0023] Preferably, the color composition can be converted into a coating by adding > 40% by mass, > 50% by mass, preferably > 55% by mass, more preferably > 60% by mass, further preferably > 65% by mass, and particularly preferably > 70% by mass and < 200% by mass, preferably < 150% by mass, more preferably < 100% by mass, further preferably < 90% by mass, and particularly preferably < 80% by mass of the liquid medium (solvent) based on the mass of the color composition. It has been shown that with this amount of solvent, a readily workable coating can be produced which can be applied to a surface using conventional application methods. For example, it can be brushed, rolled, or sprayed.

[0024] The composition according to the invention is characterized by the fact that, unlike powdered paints available on the market, it can be mixed without lumps or bubbles. Particularly advantageous for providing a lump-free and bubble-free mixable paint composition have been found to be embodiments which are not themselves completely solvent-free (for example, anhydrous) but contain a predetermined liquid content. Preferably, the liquid content is > 1% by mass, > 1.5% by mass, more preferably > 2% by mass, more preferably > 3% by mass, further preferably > 4% by mass, and particularly preferably > 5% by mass of liquid based on the total mass of the paint composition.

[0025] To achieve complete dissolution and / or particularly rapid dispersion or emulsification of the color composition in the coating material, while preventing the formation of lumps of the color composition or stable air bubbles, it is preferred that the color composition comprises at least one disintegrating agent. Such a disintegrating agent serves to break down agglomerates of the color composition upon contact with the solvent. Disintegrating agents of this type are known, for example, from pharmaceuticals and food (supplements), where they ensure complete dissolution of the preparation and thus the release of the active ingredient. A disintegrating agent can also be, for example, quartz sand or glass beads.

[0026] In a preferred embodiment, the color composition comprises kaolin and / or a kaolin derivative, particularly preferably a (partially) calcined kaolin. Alternatively or additionally, it may be advantageous for the color composition to comprise an alkaline earth compound, in particular an alkaline earth carbonate, alkaline earth sulfate, or alkaline earth silicate, or mixtures thereof. Calcium and / or magnesium compounds have proven to be particularly preferred alkaline earth compounds. In a variant, color compositions with a kaolin / kaolin derivative content of < 30% by mass, preferably < 20% by mass, more preferably < 10% by mass, further preferably < 5% by mass, and particularly preferably < 1% by mass of the liquid medium based on the total mass of the color composition are also usable.

[0027] The color composition may comprise one or more additional components besides the additive and binder. Preferably, one of these components is selected from the group consisting of filler, rheology additive, pigment, dye, emulsifier, biocide, and preservative. The addition of a kaolin and / or kaolin derivative and / or a calcium and / or magnesium-containing component has proven particularly preferred. Since the color composition is diluted with at least one solvent during the manufacture of the coating, it has proven advantageous for the color composition to have a comparatively high pigment content for color compositions, preferably a TiC>2 pigment content of > 5% by mass, preferably 10% by mass.

[0028] > 15% by mass, further preferred > 17% by mass, particularly preferred

[0029] > 20 percent by mass based on the total mass of the color composition.

[0030] TiC>2-containing pigments have proven particularly suitable. Such a TiO2-containing pigment can comprise one or both of the two TiO2 modifications, rutile and anatase. Optionally, rutile and / or anatase can be used as a coating. As can be seen from the comparative studies presented below, this results in a high quality of the coating material, as well as a high level of opacity and color appearance.

[0031] Another aspect of the present invention is a coating material which is preferably obtained by dissolving, dispersing and / or emulsifying with > 40% by mass, > 50% by mass.

[0032] > 55% by mass, more preferably 60% by mass, further preferably 65% ​​by mass, and particularly preferably > 70% by mass and < 200% by mass, preferably < 150% by mass, more preferably < 100% by mass, further preferably < 90% by mass, and particularly preferably < 80% by mass in a liquid medium (for example, water) obtained from a color composition as described above. The above mass specifications—like all other mass specifications within the scope of this invention, unless otherwise stated—refer to the mass of the color composition.

[0033] It has been shown that the color compositions according to the invention are significantly more dispersible than powder color compositions known from the prior art, such as those described above. To test the effects of this improved dispersibility, a color composition according to the invention, as well as powder color compositions known from the prior art, were dispersed in two different ways, and selected properties of the resulting coatings were determined. In Method 1, the dispersion was carried out in a manner close to that of a DIY enthusiast and as close as possible to the instructions in the respective product information for the powder color compositions known from the prior art. However, to obtain comparable results, the dispersion conditions were standardized and carried out very gently for 5 minutes at 1000 rpm using a dissolver (here, a Pendraulik laboratory dissolver, Disperlux TD 100).After a 30-minute resting period, the mixture was stirred again for 1 minute at 1000 rpm.

[0034] In comparison method 2, a single dispersion (also using a Pendraulik laboratory dissolver, Disperlux TD 100) was performed under increased energy input, namely for a period of 4 minutes at 3000 rpm, followed by a deaeration phase. This more intensive type of dispersion is intended to simulate the conditions for producing a finished paint as commonly found in hardware stores.

[0035] In a preferred embodiment, a coating material has a pigment and / or filler rub-out degree, measured by a grindometer according to DIN EN 21 524 and / or ISO 1524, after dispersion according to method 1 < 75 pm, preferably < 70 pm, more preferably < 65 pm, most preferably < 60 pm, and after method 2 < 65 pm, preferably < 60 pm, more preferably < 55 pm, most preferably < 50 pm. Thus, the pigment and / or filler rub-out degree is significantly lower than that of all comparable examples of commercially available mixed paint compositions, each of which exhibits a pigment and / or filler rub-out degree > 80 pm and in some cases even exceeds 100 pm when using at least one dispersion method.

[0036] Preferably, a coating material after dispersion according to method 1 has a viscosity > 2000 Pa«s, preferably > 2200 Pa«s, preferably > 2400 Pa«s, further preferably > 2600 Pa«s, most preferably > 2700 Pa«s and according to method 2 > 1200 Pa«s, preferably > 1400 Pa«s, preferably > 1600 Pa«s, further preferably > 1700 Pa«s, most preferably > 1800 Pa«s.

[0037] The shear stress of the coating material after dispersion is preferably (according to both method 1 and method 2) in the range of 300 - 800 Pa, preferably 350 - 750 Pa, preferably 400 - 700 Pa, more preferably 450 - 650 Pa, and most preferably 500 - 630 Pa.

[0038] This means that the rheological properties of such a coating are significantly better than those of commercially available powder-based paint mixtures and almost on par with ready-to-use coatings intended for professional use. Therefore, it can be applied using brushes or rollers, as is common with both DIY and professional paints, as well as by spraying.

[0039] The color properties of an exemplary coating according to the invention are also significantly better than those of the comparison products. If the coating is a white pigment-containing coating, the L* value (both after dispersion according to method 1 and according to method 2) is preferably > 94.75, preferably > 95, preferably > 95.25, more preferably > 95.5, further preferably > 95.75, and most preferably > 96. Additionally or alternatively, the yellow value is preferably < 6, preferably < 5, more preferably < 4.5, and most preferably < 4.

[0040] Further differences in some selected properties of exemplary coating materials according to the invention, compared to selected commercially available paints from various manufacturers, such as ready-to-use DIY paints from hardware stores, are presented below. For comparison purposes, the results of the respective tests on the various quality criteria are also compared to those of ready-to-use coating materials for professional tradespeople (professional paints).

[0041] Five different powder colors were investigated. Of these, four are commercially available "do-it-yourself" (DIY) powder colors, and one is a color composition developed according to the invention following a corresponding formulation. The mixing ratios with water given below for the commercially available powder colors correspond to the manufacturers' recommended specifications.

[0042] The term "color powder" used below refers to commercially available dry mixtures consisting of fillers and, if applicable, pigments or dyes, binders and additives.

[0043] 1. Sample N (Company W)

[0044] Recipe: 360.0 g water

[0045] 440.0 g of color powder. Preparation according to the technical data sheet: no information provided.

[0046] 2. Sample F (DM company) Recipe: 300.0 g water

[0047] 500.0 g color powder

[0048] Preparation according to the technical data sheet: Mix for 5 minutes, then allow 10 minutes of maturation time, and then mix again for 30 seconds.

[0049] 3. Sample L (Company K)

[0050] Recipe: 400.0 g water

[0051] 400.0 g of color powder

[0052] Preparation according to the technical data sheet: Mix with a rotating mixing tool until the mixture is free of agglomerates, then allow to swell for 30 minutes and stir thoroughly again.

[0053] 4. Sample B, (Company L)

[0054] Recipe: 400.0 g water

[0055] 400.0 g of color powder

[0056] Preparation according to the technical data sheet: Mix for 2 minutes with suitable machines (>750 W), then allow to swell for 30 minutes and then stir thoroughly again.

[0057] 5. Example of a coating material with a color composition according to the invention

[0058] Recipe: 400.0 g water

[0059] 554.0 g of color composition comprising color powder, additive and binder

[0060] Preparation: Mix intensively for 10 seconds, then

[0061] Let it soak for 30 minutes and then mix for another 4 minutes.

[0062] The formula mentioned in section 5 is merely an exemplary approach to solving the underlying problems. Other variations are possible. For example, the proportion of the individual components of the color powder in the paint composition can be changed to adjust the paint composition to achieve the desired properties of the paint or coating. Furthermore, depending on the components of the color powder contained in the paint composition, a different amount of water may be advantageous as an additive for the production of the coating.

[0063] Some of the formulation components of a color composition according to the invention can correspond to those used in coatings known from the prior art. This allows a generally good level of quality to be achieved compared to conventional coatings and ensures the usability of application materials available on the market.

[0064] A key difference, however, lies preferably in the fact that at least one selected component, particularly preferably a binder, exhibits exceptionally good dissolving and dispersing properties. Comparative tests conducted by the company demonstrated that the time required to achieve a lump-free solution (assessed as residue-free passage through a 45 pm sieve) of a portion of solid binder in water (magnetic stirrer, 1000 rpm) is only 3 minutes, whereas this time was 15 minutes for the comparison binder. The magnetic stirrer was chosen because it results in a comparatively low shear force input, thus resembling low-powered mixers used in private households.

[0065] Preferably, the color composition is designed, suitable, and / or intended for carrying out the process described below, as well as all process steps described in connection with the process, individually or in combination, or for carrying out individual process steps using the color composition. Conversely, the process for producing a coating material with all the characteristics described within the context of the color composition can be carried out individually or in combination. In particular, the color composition can be used to carry out the process described below.

[0066] The preparation described above is an example of a process according to the invention for producing a coating material. In general, a process according to the invention is characterized by the following steps: a) providing a first color composition comprising a color powder (fillers, pigments, etc.), an additive, and a binder, wherein the first color composition has a solvent content of < 10% by mass based on the total mass of the color composition; b) providing a solvent; c) mixing the first color composition and the solvent in a mixing device.

[0067] As explained above, this can result in a particularly homogeneously dispersed coating material.

[0068] In a particularly preferred variant of the process, the color composition is produced at a different location and time than in step a). This makes it possible to save storage and transport capacity and to provide the coating in a particularly resource-efficient manner.

[0069] It is therefore possible for a color composition to be produced at one location, transported to a second location, and made available there, where a customer or user selects a color. Based on this color selection, the color composition (optionally with one or more additional additives) is reacted with water to form a coating. This reaction preferably occurs through the dissolution and / or dispersion of at least some components of the color composition.

[0070] The production of the (dry) color composition is therefore deliberately separated in time and location from the process of converting it into a coating material or a ready-to-use suspension. It is possible that there may be several different locations for the production of the component packages of the color composition. Likewise, it is conceivable, and in many cases even intended, that there are several different locations for the preparation / production of the coating material or the ready-to-use suspension from the color composition.

[0071] A preferred method variant is in which at least one second color composition is provided with a color different from the first color composition, wherein the second color composition comprises a color powder, an additive and a binder and has a solvent content of < 10% by mass based on the total mass of the second color composition, or at least one second color composition is provided with a color different from the first color composition, wherein the second color composition comprises a color powder, an additive and a binder and has a solvent content of > 10% by mass based on the total mass of the second color composition and is provided as a paste, and this second color composition is mixed with the solvent and / or the first color composition and / or the coating obtained in c).

[0072] This variant allows a customer or user (hereinafter also referred to as end consumer) to individually define a desired color, specifically a desired shade, and to mix it by adjusting the ratio of different color compositions.

[0073] The provision of the first color composition and / or an optional second color composition is preferably based on a selection by an end user.

[0074] The selection can preferably be entered into a computer-aided selection system. Color selection can thus preferably be computer-aided. A display device connected to a computer system can preferably show a customer or user the color impression achieved with a selected mixing ratio of different color compositions. Other properties, such as the type, color, roughness, or wettability of the substrate to which the coating is to be applied, or the application method and thickness (using a brush, roller, or sprayer), could also be included in the calculation of the expected color impression. The type and / or quality of the solvent can also be included in the calculation.

[0075] In a preferred embodiment of the process, the following amounts of solvent, based on the mass of the paint composition, are added to the paint composition: > 40% by mass, > 50% by mass, preferably > 55% by mass, more preferably > 60% by mass, further preferably > 65% by mass, and particularly preferably > 70% by mass and < 200% by mass, preferably < 150% by mass, more preferably < 100% by mass, further preferably < 90% by mass, and particularly preferably < 80% by mass. It has been shown that this mixing ratio achieves the desired effect of reduced transport and storage volume while simultaneously producing a coating that is easy to apply using conventional applicators.

[0076] A particularly advantageous process variant has proven to be the use of water as the solvent. Water is readily available in large quantities and of good, controlled quality almost everywhere. Due to the almost universally known and / or easily measurable water quality, it is possible, if necessary, to add additives to the paint composition and / or coating material. These additives ensure that the desired color effect is achieved even with locally varying water quality. For example, it would be conceivable to add a material to the water, paint composition, and / or coating material that is selected from a group including a complexing agent, a pH reducer, a pH increaser, a buffer system, a descaler, and an antiscalant.

[0077] Preferably, the mixing in c) takes place in at least two stages, wherein after a first mixing process the resulting mixture is allowed to rest for a time interval T and after the time interval T a second mixing process is carried out. For example, the color composition is first stirred with water, then the dispersion produced is allowed to rest for a predetermined time interval and is subsequently stirred again.

[0078] Preferably, the second mixing process is carried out under higher shear forces than the first. This could be achieved, for example, by using a higher rotational speed of a stirring device. Preferably, the rotational speed of the stirring device in a second mixing process is at least s1.2, preferably > 1.5, more preferably e1.8, more preferably e2, and most preferably e3 greater than in a previous first mixing process. It has been shown that this results in a particularly low proportion of larger agglomerates in the coating material, which has a positive effect on the opacity and application.

[0079] This doesn't necessarily have to involve undesirable waiting times for the purchasing (end) customer. Such waiting times, caused by beneficial swelling, settling, or deaeration periods of the mixtures, are avoided by having end customers place their desired color order in advance, for example, via online ordering, specifying their preferred pick-up date or time period. The entity preparing the ready-to-use paint, such as a hardware store, specialist retailer, or even a discount store with the appropriate technology, confirms the order and also specifies any alternative pick-up dates and times. The entire process can be digitized and tracked on a per-order basis, for example, using a QR code or other tracking system. Changes in the process flow can be communicated directly to the client and / or end customer.

[0080] The smooth process, and therefore the quality of the paint, is ensured on-site by trained personnel and a suitable working environment (such as computer-aided process control) at the point where the ready-to-use paint is prepared. Ideally, cleaning, waste management, and wastewater control systems are also established at the mixing site. Unlike when a (private) end user mixes paint themselves, these systems ensure that contamination (of the paint, equipment, and the environment) is avoided. This permanently eliminates the need for individual, potentially very disadvantageous, and wastewater-intensive procedures that occur when mixing dry paints privately using state-of-the-art methods.

[0081] A further significant advantage of the inventive process and the process variants described above is that a sufficiently high color quality can be achieved and reproduced according to customer requirements. The necessary equipment is comparatively inexpensive to invest in and requires little cleaning, which has a positive effect on minimizing residual materials and wastewater. The process is fast and can be implemented locally (for the customer or user). In most cases, this makes it possible to provide a user with a reproducible coating within less than 24 hours, tailored to their individual needs and wishes, in virtually any quantity and with consistent quality. It should be specifically emphasized that the resulting color quality can be provided at such a high level that the customer or user can also be a professional tradesperson.

[0082] Testing of various mixing methods has shown that commercially available mixers, such as those used in hardware stores for tinting conventional paints, can already deliver sufficient color quality with minimal effort. Preferably, shear force is introduced into the paint composition provided in a) before the solvent is added. This shear force is preferably introduced using a stirring device, which is preferably part of the mixing device, and is carried out in step c). This allows, for example, the paint composition to be pulverized in an additional step immediately before mixing with water. This treatment has been shown to offer advantages during mixing, as the paint composition dissolves better or forms a more stable emulsion or suspension.

[0083] Preferably, the (optionally shear-treated) paint composition is transferred as a (dry) powder into a container of a size appropriate to the amount of paint selected by the applicant (e.g., 5, 10, 20 liter bucket, drum, tank) and mixed with the necessary / calculated amount of solvent (e.g., water).

[0084] The mixing process can be supported by dispersing agents, which are added to the container before mixing. Preferably, the mixing in c) is supported by a dispersing agent. A medium-sized solid (d50 sieve analysis) of 5 mm to 50 mm is preferably used as the dispersing agent. Particularly preferred are spheres made of a material from the group consisting of glass, ceramics, aluminum oxide, quartz sand, quartz gravel, and other inert and abrasion-resistant materials. It has been shown that these do not negatively affect the color properties. Furthermore, these or similar dispersing agents lead to better and, above all, faster dispersion of the (dry) paint during the mixing process with the solvent (water). After mixing, these dispersing agents can be removed and reused. Preferably, stirring and dispersion are carried out without these or other dispersing agents.

[0085] Comparative examples

[0086] Uniform preparation of the tested (dry) color compositions

[0087] As explained above, the manufacturers of the paint compositions used for comparison in the test provide different instructions for their preparation. To create optimal comparison conditions and to closely reflect the capabilities of a DIY enthusiast and the specifications of the technical data sheets, the preparation was started on a dissolver for 5 minutes at 1000 rpm according to Method 1 described above, followed by a 30-minute resting period and then stirring for 1 minute at 1000 rpm.

[0088] The comparative test based on coatings produced according to method 2 is based on dispersion over a period of 4 minutes at 3000 rpm with a subsequent deaeration phase.

[0089] Results of comparative tests in accordance with EN 13300

[0090] 1 Grindometer

[0091] At the coarsest particle size, there are significant differences between the individual colors. While some agglomerates are still present when mixed according to DIY conditions as described in Method 1, the (professional) dispersion according to Method 2 reveals the actual top-cut of the ingredients. The exemplary formulation according to the invention is significantly finer, with a considerably lower top-cut, and contains virtually no agglomerates.

[0092] 2 Surface image

[0093] The coatings of commercially available, mixed paints contain pronounced microfoam, macrofoam, and isolated agglomerates, which, when dispersed according to Method 1, completely ruin the surface appearance. Except for the paint from manufacturer K, these defects almost completely disappear in the other four paints after dispersion according to Method 2 and deaeration.

[0094] - = poor surface finish - / o = suboptimal + = good surface finish

[0095] 3 Rheology

[0096] Dispersing according to method 2 and venting results in a significant reduction in viscosity and a slight reduction in shear stress compared to method 1.

[0097] Method 1 Method 2

[0098] Comparison of professional paints DIY paint comparison

[0099] 4 Color location

[0100] In direct comparison, the inventive paint performs best. Individual values ​​(such as the L* value) can be further improved with professional dispersion and deaeration according to Method 2. Method 1

[0101] Method 2

[0102] Comparison of professional paints

[0103]

[0104] DIY comparison

[0105] 5 gloss

[0106] Based on the results, all colors can be classified as matte. However, it appears that the mattifying effect decreases with professional dispersion, caused by the disappearance of agglomerates and macrofoam, leading to an increase in gloss.

[0107] Method 1

[0108] Comparison of professional paints

[0109] DIY comparison

[0110] 6 Wet abrasion

[0111] While the coatings based on color compositions K and L rub off very quickly, the other three coatings are just on the borderline between wet abrasion class 2 and 3 (at 20 pm). Wet abrasion class 2 is only achieved by the coating from company W (Method 1).

[0112] Method 2

[0113] Comparison of professional paints

[0114] DIY comparison

[0115] 4.7 Coverage capacity

[0116] The coatings from DM and K performed rather poorly, while the other three coatings behaved approximately the same. However, significant differences in opacity were observed between the two production methods, 1 and 2. In the 150 m range, dispersion according to method 2 and aeration resulted in an improvement of +1.0 to +3.5 points.

[0117] The opacity, which is one of the most important performance characteristics of a paint, could be increased to 99.7% at a layer thickness of 150 µm in one formulation variant of the dry paint according to the invention. This exemplary formulation thus achieves the performance level of professional paints as described below. The application according to the invention is therefore not limited to the DIY sector, but can also be extended to professional applications if required. Method 1

[0118] Method 2 Comparison of professional paints

[0119] DIY comparison 8. Yield: The yield values ​​after dispersion, based on both DIY and professional dispersion methods, confirm the previous results. Here too, better dispersion leads to sometimes significantly better results.

[0120] Method 1

[0121] Method 2

[0122] Comparison of professional paints

[0123] DIY comparison

[0124] The applicant reserves the right to claim all features disclosed in the application documents as essential to the invention, provided they are novel individually or in combination compared to the prior art. It is further noted that the figure also describes features which may be advantageous on their own. A person skilled in the art will immediately recognize that a particular feature described in the figure may be advantageous even without incorporating other features from that figure. Furthermore, a person skilled in the art will recognize that advantages may also arise from a combination of several features shown in the figure.

Claims

Low-solvent paint composition, its production, processing and use Patent claims 1. A color composition comprising a color powder, an additive and a binder, characterized in that it has a solvent content of < 10% by mass based on the total mass of the color composition and can be converted into a coating material by the addition of solvent.

2. Color composition according to claim 1, characterized in that the solvent content is <10% by mass, preferably <8% by mass, more preferably <5% by mass, further preferably <3% by mass and particularly preferably <1% by mass based on the total mass of the color composition.

3. Colour composition according to one of the preceding claims, characterized in that it is water-soluble, water-emulsifiable or water-suspendenable.

4. Colour composition according to one of the preceding claims, characterized in that it comprises at least one disintegration agent.

5. Method for producing a coating material, comprising the steps of: a) providing a first color composition comprising a color powder, an additive and a binder, wherein the first color composition has a solvent content of < 10% by mass based on the total mass of the color composition, b) Providing a solvent, c) Mixing the first color composition and the solvent in a mixing device.

6. Method for producing a coating material according to claim 5, characterized in that the color composition is produced at a different location and time than a).

7. A method for producing a coating according to claim 5 or 6, characterized in that at least one second color composition is provided with a color different from the first color composition, wherein the second color composition comprises a color powder, an additive and a binder and has a solvent content of < 10% by mass based on the total mass of the second color composition, or at least one second color composition is provided with a color different from the first color composition, wherein the second color composition comprises a color powder, an additive and a binder and has a solvent content of > 10% by mass based on the total mass of the second color composition and is provided as a paste, and this second color composition is mixed with the solvent and / or the first color composition and / or the coating obtained in c).

8. A method for producing a coating according to one of claims 5-7, characterized in that the color composition is supplemented with > 40% by mass, > 50% by mass, preferably > 55% by mass, more preferably 60% by mass, further preferably 65% ​​by mass and in particular preferably 70% by mass and < 200% by mass, preferably < 150% by mass, more preferably < 100% by mass, further preferably < 90% by mass and in particular preferably < 80% by mass of the solvent based on the mass of the color composition.

9. Method for producing a coating material according to one of claims 5-8, characterized in that the mixing in c) is carried out in at least one stage, but preferably in two stages, wherein after a first mixing process the mixture obtained is left to rest for a period of time T and after the period of time T a second mixing process is carried out, wherein preferably the second mixing process is carried out under higher shear forces than the first mixing process.

10. Method for producing a coating material according to one of claims 5-9, characterized in that the provision of the first color composition and / or an optional second color composition is based on a selection by an end user, wherein the selection is preferably entered in a computer-aided selection device.

11. Method for producing a coating material according to one of claims 5-10, characterized in that a shear force is introduced into the color composition provided in a) prior to the addition of the solvent, wherein the shear force is preferably introduced by means of a stirring device, wherein the stirring device is preferably part of the mixing device by means of which step c) is carried out.

12. Method for producing a coating according to one of claims 5-11, characterized in that the mixing in c) is supported by a dispersing aid, wherein the dispersing aid is preferably a solid of medium size (d50 sieve analysis) of 5 mm to 50 mm, particularly preferably spheres made of a material from the group comprising glass, ceramics, aluminium oxide, quartz sand, quartz gravel and other inert and abrasion-resistant materials.

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