Powder paint composition and method for producing a powder paint composition

Abstract

The invention provides a method for producing a water dispersible powder composition for a paint comprising providing as powder components: (b) a binder with (b1) 1-20 wt.% of at least one cation-metal oxide and / or hydroxide powder, (b2) 5-40 wt.% of at least one water-dispersible polymer (b3) 0-5 wt.% of at least one co-solvent, further comprising as powder components: (c1) a paint film strength improving material comprising 10-50 wt.% of at least one Calcium-Silicate -water (CSH) composition, (d1) 5-60 wt.% of at least one pigment composition, and (e1) at least one rupture preventing material comprising 0-10 wt.% of at least one fibre material, wherein all wt.% are based on the total weight of the composition, therewith providing a powder mixture, and the method further comprising intimately mixing said powder mixture, therewith providing the water dispersible powder composition with a particle size distribution with D99 of between 30 and 200 pm, and D4,3 of 5-30 pm, wherein the particle size distribution is measured using a Malvern Mastisizer 3000 plus Hydro MV sample dispersion unit.

Description

[0001] POWDER PAINT COMPOSITION AND METHOD FOR PRODUCING A

[0002] POWDER PAINT COMPOSITION

[0003] Field of the invention

[0004] The invention relates to a method for producing a water dispersible powder composition for a paint.

[0005] Background of the invention

[0006] Coating compositions and paint are well known. Mostly, these coating compositions comprise a binder, pigments, and a solvent for modifying the rheology of the coating composition for allowing application onto a surface. Often, the binder is a polymer, often air-drying or chemically curing. The solvent is often selected form water or an organic solvent.

[0007] It was found that coating compositions or paints can also be provided as powder compositions. These powder compositions can be mixed with water to form a paint, for instance a wall paint, when it has to be used. In particular, water can be added just before application. Some of the advantages of these powder compositions are clear, for instance a reduced transport volume. An example of these powder compositions is in the following application.

[0008] CN1144832A in its abstract states: ’’powdered solid paint contains organic components (1-5 Wt.5) including water-soluble epoxy resin, urea-formaldehyde resin, polyamide and other water-soluble adhesive, inorganic components (89-98.5 Wt.%) including white cement, high-Al cement, heavy or light calcium carbonate, lime and gypsum, and chemical aids (0.5-6 Wt.%) including defoaming agent, pigment, disperser, setting retarder and expansion inhibitor, and features excellent properties and low cost.”

[0009] CN10500173A in its abstract discloses: “creative environment-friendly dry powder paint for wall decoration. The creative environment-friendly dry powder paint comprises, by weight, 3-30 parts of titanium dioxide, 3-30 parts of white cement, 20-60 parts of acrylic acid rubber powder, 5-40 parts of lime and / or wollastonite, 0.02-0.8 part of cellulose, 0.5-12 parts of citric acid and 0.1-3 parts of defoamer. The creative environment-friendly dry powder paint for wall decoration is inorganic active dry powder wall paint which is resistant to water, crack and weather, free of VOC and formaldehyde, free of the saltpetering phenomenon and quite good in workability, the later-period strength of a coating is high, and the creative environment-friendly dry powder paint can be widely applied to painting and decorating of inner walls and outer walls.”

[0010] Summary of the invention

[0011] Disadvantages of prior art are that the provided water-dispersible powder composition when mixed with water does not provide a paint, or provide a paint that does not match performance and characteristics of current ready-to-use liquid paint, and / or the paint does not have an acceptable consistency, which may lead to spattering, poor transfer or usability issues when applying the paint on a wall. This is in particular the case when used for coating mineral substrates. Further disadvantages of such prior art water-dispersible powder compositions include the presence of TiCh, typically needed to provide the required opacity, but undesired due to its potential toxicity and high carbon footprint, the presence of portland cement or white cement, also undesired due to its high carbon footprint, and the fact that a low wet scrub resistance (typically class 2, 3, or worse) is unavoidable.

[0012] Hence, it is an aspect of the invention to provide an alternative water-dispersible powder composition, which preferably further at least partly obviates one or more of above-described drawbacks.

[0013] There is provided a method for producing a water dispersible powder composition for a paint comprising providing as powder components:

[0014] (b) a binder, the binder comprising

[0015] (bl) 1 - 20 wt.% of at least one powder, in particular 2 - 16 wt.%, more in particular 5 - 15 wt.%, selected from cation-metal oxide MO powders, cation-metal hydroxide MOH powders, and combinations thereof, in particular wherein the valence of the metal M is selected from2+and3+, and in particular wherein the cation is selected from Group 2 elements, more in particular from Ca, and Mg, and combinations thereof, and more in particular wherein the cation is selected from Al, Fe, and combinations thereof, (b2) 5 - 40 wt.% of at least one water-dispersible polymer, in particular 10 - 30 wt.% polymer, more in particular 15 - 21 wt.% polymer, in particular a hydrolysed polymer, more in particular selected from anionic polysaccharides, from polyvinyl alcohols from acidic polymers, from a polystyrene sulphonates, from acidic biopolymers, from a pectin, from a carrageenan, from a gelatine, from polycarboxylic acid polymers, even more in particular from polyvinyl acetate, from polyethene-vinyl acetate, polyethylene-vinyl laurate, from copolymers thereof, and combinations thereof;

[0016] (b3) 0 - 5 wt.% of at least one co-solvent, in particular 0.1 - 5 wt.%, more in particular 0.1 - 2 wt.%, in particular a co-solvent selected from co-solvents comprising at least one OH-moiety, and / or at least one COOH moiety, and / or at least one NH2 moiety, more in particular such as alcohols, alkanols, carboxylic acids, even more in particular polyvinylalcohol, further comprising as powder components:

[0017] (cl) 10-50 wt.% of a paint film strength improving material selected from at least one Calcium-Silicate -water (CSH; (CaO)x(SiO2)y(H2O))Z) composition, a calcium- alumino-silicate compound and a mixture thereof, in particular 10 - 30 wt.%, more in particular 15 - 21 wt.%, wherein the (CaO)x(SiO2)y(H2O))Zis selected from CSH compositions wherein x e [0.25, 0.75], in particular x e [0.4, 0.6], , wherein y e [0.25, 0.75], in particular y e [0.4, 0.6], , wherein z e [0.02, 0.5], in particular z e [0.02, 0.25],

[0018] (dl) 5 - 60 wt.% of at least one pigment composition, in particular 30 - 60 wt.% pigment composition, and

[0019] (el) 0 - 10 wt.%, in particular 3 - 4 wt.%, of at least one rupture preventing material comprising at least one fibre material, selected from natural fibers, in particular from lignin, cellulose, lignocellulose, hemicellulose, and a combination thereof, either as such, or in combination, wherein all wt.% are based on the total weight of the composition, therewith providing a powder mixture, and the method further comprising intimately mixing said powder mixture, under a high shear, in particular at 20 - 9000 rpm, more in particular in a high shear mixer, more in particular a paddle mixer, therewith providing the water dispersible powder composition with a particle size distribution with D99 of between 30 and 200 pm, and D4,3 of 5 - 30 pm, wherein the particle size distribution is measured using a Malvern Mastisizer 3000 plus Hydro MV sample dispersion unit.

[0020] Powder component (bl), also sometimes in the art referred to as amphoteric powder, is hereinbelow also referred to as “cation-metal oxide and / or hydroxide powder”.

[0021] There is further provided a method for providing a paint for application onto a surface, comprising providing 2 weight parts of the water dispersible powder composition, and 0.5 - 2 weight parts of water, in particular 0.8 - 1.2 weight parts of water, more in particular 0.9 - 1.1 weight parts of water, mixing the water dispersible powder composition with water, therewith forming a paint, and applying the paint onto the surface, in particular applying the paint within 36 hours, in particular within 24 hours, more in particular within 4 hours, even more in particular within 2 hours after mixing with water, more in particular wherein the surface is selected from a wall, from a ceiling, such as from a brick surface, from a concrete surface, from a cement, from a plaster, from a bitumen surface, from wood, from a metal, from glass, from paper, and from natural stone.

[0022] The method includes brush, roller, and spray applications.

[0023] The paint of the present invention surprisingly has the look and feel, combined with the mechanical properties, both when applying and when applied, of traditional wall paint.

[0024] There is further provided a wall paint powder composition comprising the water dispersible powder composition.

[0025] There is further provided a paint composition obtainable by mixing the water dispersible powder composition with water, in particular in a weight ratio powder : water of between 1:3 and 3:1 for providing a water based coating composition, in particular a wall paint.

[0026] There is further provided a granulate produced using the water dispersible powder composition. In an embodiment, the granulate has a size of 1-10 mm. In an embodiment, the granulate has a size of 1-5 mm. It was found that when provided as granulate, the granulate was relatively easy to disperse in water. The provision as granulate avoided dust when making the water dispersion for producing the paint composition. The size of the granules allows sufficient accurate dosing.

[0027] In general, a dispersion is a mixture in which a first compound is distributed in a second compound. Examples are colloids, emulsions, suspensions, smoke. Producing such a dispersion is referred to as dispersing. A dispersion under laser illumination is often milky in appearance.

[0028] Below, a dispersion compound (left column) in a dispersant: solid liquid gas solid composite suspension smoke liquid suspension emulsion mist gas foam foam gas

[0029] In paint technology or coatings technology, a dispersion is a mixture of a binder and a solid or liquid compound in a liquid. This liquid often is water, while the dispersed compound (for instance dispersions) are often used in latex wall paints, they can also be diluted with water.

[0030] The water dispersible powder composition can be used for making a paint that for instance can be used for application on mineral substrates. The water dispersible powder composition is based on providing a hybrid binder. In this context, a hybrid binder is a combination of a cation-metal oxide and / or hydroxide powder and a water-dispersible polymer, for instance a film forming self-dispersible emulsion. This resulting water dispersible powder composition, including the paint film strength improving material of the invention, allows the complete avoidance of TiCh as opacifying pigment, and still resulting in acceptable opacifying and whiteness properties and Wet Scrub Resistance. In an embodiment, an opacifying white inorganic pigment / filler combination is used. Furthermore, in an embodiment little to no co-solvents or coalescents are used for film forming. As a result, no emission of volatile organic compounds occurs during application and drying of a ready-made liquidized (addition of water) powder paint that results from mixing the water dispersible powder composition with water.

[0031] More particularly, such a paint composition according to the invention has, when measured according to ISO 11890-2, a VOC (volatile organic compounds) content of 50 g / liter or less, in particular of 30 g / liter or less. In an exemplary embodiment of the invention, the product according to the present invention has a carbon footprint of less than 220 g, in particular less than 200 g, per m2of painted surface having 99.5% opacity.

[0032] The co-solvent in an embodiment can function as a film forming aid.

[0033] The composition can be provided as a powder with which it is easy to produce a water coating composition or water borne coating composition.

[0034] In general, liquid-solid mixing is done to suspend coarse free-flowing solids, or to break up lumps of fine agglomerated solids. In the current case, the powder components are intimately mixed, resulting in the defined water dispersible powder composition. In an embodiment, to attain the described water dispersible powder composition, the powder components are mixed using a mixer. For instance, a mixer can be used that comprises paddles (a mixing paddle) and in an embodiment the mixer is set to 20-9000 rotations per minute (rpm). Mixing can be done in a batch mixer, or in a flow-through mixer. In an embodiment, a dry-blender can be used. The impeller diameter in an embodiment is between 10 and 200 cm, in particular between 10 and 100 cm. A small amount of water may be added during the mixing for producing agglomerates after intimately mixing of the powder components.

[0035] In the current context, reference is made to paint. In general, this is a coating composition. In general, a paint is a composition, mostly liquid, that can be applied to a surface to provide protection and / or for aesthetic purposes. There are many types of paints, adjusted for the use. For instance car paint, protective paint for instance for steel constructions, DIY paints, and more. The current water dispersible powder composition is in particular suitable for application on mineral substrates like stony walls, concrete surfaces, plaster board, dry walls, wall paper, previous paint layers, bitumen, natural stone, and the like. For instance, the current water dispersible powder composition can be used as wall paint. Often, these paints can also be used for ceilings, for instance.

[0036] Before actual application, the current water dispersible powder composition is dispersed in water. For the current water dispersible powder composition, just tap water is suitable. The temperature of the is not very critical, often room temperature is sufficient.

[0037] The current water dispersible powder composition does not require a preservative, a stabilizer, dispersants, nor does it require a biocide, fungicide or the like. Small amounts may be used for protection after application. The paint produced using the water dispersible powder composition can be applied to a surface in most known manners. Usually, a roller or brush application are selected. It is also possible to apply said paint to a surface using a spray gun. The paint resulting from the water dispersible powder composition is most often applied in layer thickness of between 1-200 microns. In some instances, two or more layers are applied.

[0038] The water dispersible powder composition allows for an easy transport to a site of use with no transport of water. Furthermore, it has a very long shelf life, for instance at least five year.

[0039] The paint from the water dispersible powder composition can provide a high opacity, as high as 97%, even 98%, 99% or even 99.5 % (Class 1), with just one layer, and with minimal or even no addition of TiCh (i.e. less than 0.01 wt.%, more particularly less than 0.001 wt.% of TiCh). The composition of the present invention thus has a significantly lower carbon footprint than conventional water dispersible powder compositions.

[0040] The paint from the water dispersible powder composition can be formulated in such a way that it is non-toxic, even during application. Some even refer to it as applicable “ while baby sleeps in the room”....

[0041] It was found that the water dispersible powder composition allowed the provision of a coating composition which once applied provides a high hiding power, as high as 95%, even 98%, and often even a remarkable 99%, with a spreading rate of 8 m2 / litre.

[0042] The paint from the water dispersible powder composition can be formulated in such a way that the resulting coating layer has a high scrub resistance. It is even possible to attain for instance a class 2 wet scrub resistance (ISO 11998), and with careful formulation even higher (Class 1), in particular without addition of TiO2.

[0043] The paint from the water dispersible powder composition allows a formulation that can be applied onto moist surfaces. Further advantages of the water dispersible powder composition of the present invention include but are not limited to high adhesive powder to various substrates, a lack of sensitivity towards storage temperatures and temperatures during transportation (i.e. the composition can be stored or transported at temperatures below 0°C but also at temperatures as high as 35-40°C), provides for a breathable coating layer on substrates, and / or having high UV resistance. Surprisingly, the advantages of the water dispersible composition of the invention are with achieved without the need to add TiCh and without addition of biocides. There is further provided in the composition of method at least one pigment composition. The at least one pigment can be either scattering or translucent. A pigment usually provides opacifying properties to a coating composition, for instance whiteness or alternative colours. Any general pigment used in coating composition applications can be used. Examples of pigment compositions according to the invention include conventionally used pigment compositions comprising white, scattering pigments like barium sulphate, zinc oxide, zinc sulphide, coloured scattering pigments like iron oxide, ground brick, and any other pigment used in coating compositions. As the skilled person is aware, pigment compositions are often a mixture of pigment(s) and filler(s) (see in this respect also en.wikipedia.org / wiki / Mixture; en.wikipedia.org / wiki / Chemical_ substance). In a preferred embodiment, the current water dispersible powder composition allows a coating composition that has a high opacity, even with a minimal amount of titanium dioxide TiCh or even avoiding the use of TiCh completely.

[0044] Detailed description of the invention

[0045] In an embodiment, the at least one co-solvent comprises at least one selected from alcohols, alkanols, carboxylic acids and mixtures thereof. In particular, the at least one co-solvent comprises Cn-based alcohols, alkanols, carboxylic acids and mixtures thereof. More in particular, the at least one co-solvent comprises polyvinylalcohol (PVA).

[0046] In an embodiment, the at least one water-dispersible polymer comprises at least one hydrolysed polymer. In an embodiment, the hydrolysed polymer can be selected from polyvinyl acetate, polyethene-vinyl acetate, polyethylene-vinyl laurate, copolymers thereof, and combinations thereof.

[0047] In an embodiment of the invention, the at least one pigment composition (dl) comprises a pigment selected from the group consisting of white, scattering pigments like barium sulphate, zinc oxide, zinc sulphide, and coloured scattering pigments like iron oxide and ground brick.

[0048] In an embodiment of the method the at least one pigment composition (dl) comprises 0.5 - 60 wt.% of a BaSCU - ZnS powder mixture in a weight ratio BaSCU: ZnS of 1:10 to 10:1. In an embodiment thereof the at least one pigment composition (dl) comprises 5 - 40 wt.% BaSCU. In an embodiment thereof the at least one pigment composition (dl) comprises 10 - 30 wt.% BaSCU. In an embodiment thereof the at least one pigment composition (dl) comprises 18 - 25 wt.% BaSCU. In an embodiment the at least one pigment composition (dl) comprises 5 - 40 wt.% ZnS. In an embodiment the at least one pigment composition (dl) comprises 10 - 30 wt.% ZnS. In an embodiment the at least one pigment composition (dl) comprises 12 -20 wt.% ZnS.

[0049] In an embodiment of the method, the water dispersible powder composition comprises 1 - 10 wt.% of said at least one rupture preventing material (el) with said at least one rupture preventing material providing the fibre material. In an embodiment, the water dispersible powder composition comprises 2 - 7 wt.% of said at least one rupture preventing material (el). In an embodiment, the water dispersible powder composition comprises 2 - 5 wt.% of said at least one rupture preventing material (el).

[0050] In an embodiment, the fibres of said at least one rupture preventing material (el) have a length of 10 - 200 pm. In an embodiment thereof, the fibres have a length of 10 - 100 pm.

[0051] In an embodiment of the method, the fibre material of the water dispersible powder composition is plant based. Examples are fibers from cotton, hemp, wood, annual plants, algae.

[0052] In an embodiment of the method, the metal M in the cation-metal oxide and / or hydroxide powder is selected from Group 3 elements. Alternatively or in combination, the metal M is selected from Group 8 elements. In a particular embodiment, the metal M in the cation-metal oxide and / or hydroxide powder is selected from Fe, Al, and combinations thereof.

[0053] The paint film strength improving material of the invention is selected from at least one Calcium-Silicate-water (CSH; (CaO)x(SiO2)y(H2O))Z) composition, a calcium-alumino-silicate compound and a mixture thereof, in particular 10 - 30 wt.%, more in particular 15 - 21 wt.%, wherein the (CaO)x(SiO2)y(H2O))Zis selected from CSH compositions wherein x e [0.25, 0.75], in particular x e [0.4, 0.6], , wherein y e [0.25, 0.75], in particular y e [0.4, 0.6], , wherein z e [0.02, 0.5], in particular z e [0.02, 0.25],

[0054] In this respect, reference is made to the CSH phase diagram in Figure 1. As the skilled person understands, x, y, and z represent the amount of water (z), CaO (x) and SiO2 (y) in the CSH. X, y, and z range from 0 to 1, where 1 stands for 100% and 0 stands for 0%. Thus, for the CaO comer x is 1 (which means it is pure CaO), and y and z are 0 (i.e. no CaO present); for the SiO2 comer y is 1 (i.e. pure SiO2), and x and z are 0 (i.e. no S1O2 present), and wherein for the H2O comer, z is 1 (i.e. pure water), and x and y are 0 (i.e. no water present). Furthermore, in Figure 1 support lines are visible for determining the respective values of x, y, z for a given point in the figure.

[0055] In an embodiment of the method, the CSH is selected from CSH’s like a-CSH, Afwillit, Bultfonteinit, Dellait, Foshagit, Gyrolit, Hillebrandit, Jaffeit, Jennit, Killalait, Klinotobermorit, K-phase, Okenit, Reyerit, Rheinhardtbraunsit, Tobermorite, Truscottit, Xonotlite, Z-phase, and combinations thereof.

[0056] In an embodiment of the method, the CSH is selected from 9AT, IOAT, 11AT, 14AT, a-CSH, Afwillit, Bultfonteinit, Dellait, Foshagit, Gyro lit, Hillebrandit, Jaffeit, Jennit, Killalait, Klinotobermorit, K-phase, Okenit, Reyerit, Rheinhardtbraunsit, Truscottit, Xonotlite, Z-phase, and combinations thereof. It is noted that 9AT, IOAT, 11 AT, 14AT are all forms of Tobermorite. Thus, 9AT is short for 9AT Tobermorite, IOAT is short for IOAT Tobermorite, 11AT is short for 11AT Tobermorite, and 14AT is short for 14AT Tobermorite (see Figure 1 for details on the composition).

[0057] In an embodiment of the method, the water dispersible powder composition further comprises (fl) 0.25 - 3.0 wt.% of at least one rheology modifier. In an embodiment the water dispersible powder composition comprises 0.5 - 2.5 wt.% of at least one rheology modifier. Examples of rheology modifiers:

[0058] Polyurethanes, latex, styrene / butadiene,

[0059] Clays - attapulgite which also disperses suspensions, bentonite (both flocculating and non-flocculating), and other montmorillonite clays. Usually clays, when dry, exist as a very fine powder, facilitating dispersion and compatibility with other ingredients. Clays generally make matte surfaces, in spite of their fine particulate nature. Not only paints and inks, but other industries such as pharmaceutical, construction, and cosmetics, especially hair styling aids and facial detoxifying masks increasingly favor bentonite and attapulgite clays over other rheology modifiers, dispersion aids, antifoam, and numerous niche uses which exploit the numerous inherent qualities which have drawn artisans to this material. Clays are sustainably sourced and do not involve any egregious environmental damage, which were among the cheapest bulk materials until recently, when the pricing went up steadily, following the upsurge in its use pattern. Examples of rheology modifiers are:

[0060] Cellulosics - CMC, HMC, HPMC, and others, are chemically substituted cellulose macromolecules. The hydroxyl groups are substituted by other functional groups, such as methyl or propyl. The amount of substitution and molecular weight determine viscosity of the solution, assuming concentration stays the same; adding more also increases viscosity.

[0061] Sulfonates - Sodium or calcium salts, good water retention, versatile, and highly efficient.

[0062] Gums - guar, xanthan, cellulose, locust bean, and acacia are the main ones.

[0063] Saccharides - carrageenan, pullulan, konjac, and alginate, sometimes called hydrocolloids, these thickeners are extremely versatile and specific in function — each has a series of grades or types which behave differently, for example kappa carrageenan will form strong gels (potassium activated) but iota carrageenan will not form gels and only thickens.

[0064] Proteins - Casein, collagen, and sometimes albumin.

[0065] Modified castor oil - much like cellulose, castor oil has hydroxyl groups, unlike other oils which at most have double bonds, which castor oil also has, but most substitutions occur at the hydroxyl moieties, allowing exotic derivatives with myriad properties. Examples of castor oil derivatives are for example Organosilicones - Silicone resins, dimethicones, and modified silicones.

[0066] A further example of a rheology modifier is a super plasticizer. In an embodiment the water dispersible powder composition comprises 0.5 - 2.5 wt.% of the at least one super plasticizer. In an embodiment, the water dispersible powder composition comprises 0.8 - 2.0 wt.% of the at least one super plasticizer. In an embodiment, the water dispersible powder composition comprises 1.0 - 2.0 wt.% of the at least one super plasticizer.

[0067] Super plasticizers are also known as high range water reducers. In general, super plasticizers are synthetic polymers. Examples of super plasticizers are:

[0068] Lignosulphonates as their sodium salts.

[0069] Further compounds used as superplasticizers include:

[0070] Sulfonated naphthalene formaldehyde condensate, sulfonated melamine formaldehyde condensate, acetone formaldehyde condensate, polycarboxylates ethers, cross-linked melamine- or naphthalene-sulfonates, referred to as PMS (polymelamine sulfonate) and PNS (polynaphthalene sulfonate). They are prepared by cross-linking of the sulfonated monomers using formaldehyde or by sulfonating the corresponding crosslinked polymer. Naphthalenesulfonate / formaldehyde polymer.

[0071] Polycarboxylate superplasticizer stabilizing a colloidal suspension through steric interactions thanks to its lateral chains.

[0072] Ionomers bearing negatively charged groups (sulfonates, carboxylates, or phosphonates).

[0073] These compounds can be used in combinations thereof.

[0074] In an embodiment of the method, the water dispersible powder composition further comprises (gl) 0.05-2.0 wt.% of at least one hydrophobic additive, in particular 0.2 - 1.0 wt.%, more in particular 0.25-0.5 wt.%.

[0075] In an embodiment of the method, the water dispersible powder composition further comprises (hl) 0.05-1.0 wt.% of at least one wetting agent. In an embodiment, the water dispersible powder composition comprises 0.1 - 0.5 wt.% of the at least one wetting agent. In an embodiment, the water dispersible powder composition comprises 0.2-0.4 wt.% of the at least one wetting agent.

[0076] Wetting agents are also referred to as surfactants.

[0077] Examples of wetting agents are: ethoxylates, fatty alcohol ethoxylates like narrow-range ethoxylate, octaethylene glycol monododecyl ether and pentaethylene glycol monododecyl ether, alkylphenol ethoxylates (APEs or APEOs) like nonoxynols and triton X-100, fatty acid ethoxylates, special ethoxylated fatty esters and oils, ethoxylated amines and / or fatty acid amides like polyethoxylated tallow amine, cocamide monoethanolamine and cocamide diethanolamine, terminally blocked ethoxylates like poloxamers, fatty acid esters of polyhydroxy compounds, fatty acid esters of glycerol like glycerol monostearate and glycerol monolaurate, fatty acid esters of sorbitol, spans like sorbitan monolaurate, sorbitan monostearate and sorbitan tristearate, fatty acid esters of sucrose, alkyl polyglucosides, like decyl glucoside, lauryl glucoside and octyl glucoside.

[0078] In an embodiment of the method, the water dispersible powder composition further comprises (jl) 0.25 - 2.0 wt.% of at least one defoamer. In an embodiment, the water dispersible powder composition comprises 0.5 - 1.5 wt.% of the at least one defoamer. In an embodiment, the water dispersible powder composition comprises 0.65 - 0.8 wt.% of the at least one defoamer. Examples of defoamers, also referred to as anti-foaming agents, are for instance oil-based defoamers. Oil-based defoamers have an oil carrier. The oil might be mineral oil, vegetable oil or any other oil that is insoluble in the foaming medium, except silicone oil. An oilbased defoamer also contains a wax and / or hydrophobic silica to boost the performance. Typical waxes are ethylene bis stearamide (EBS), paraffin waxes, ester waxes and fatty alcohol waxes. These products might also have surfactants to improve emulsification and spreading in the foaming medium.

[0079] Other defoamers are powder defoamers. Powder defoamers are in principle oilbased defoamers on a particulate carrier like silica.

[0080] Yet other defoamers are water-based defoamers.

[0081] Water-based defoamers are different types of oils and waxes dispersed in a water base. The oils are often mineral oil or vegetable oils and the waxes are long chain fatty alcohol, fatty acid soaps or esters. These are normally best as deaerators, which means they are best at releasing entrained air.

[0082] Yet other defoamers silicone-based defoamers.

[0083] Silicone-based defoamers are polymers with silicon backbones. These might be delivered as an oil or a water-based emulsion. The silicone compound consists of a hydrophobic silica dispersed in a silicone oil. The silicone compound might also contain silicone glycols and other modified silicone fluids.

[0084] Yet other defoamers are polydimethylsiloxane.

[0085] Less favourable defoamers are fluorosilicones.

[0086] Yet other defoamers are EO / PO-based defoamers contain polyethylene glycol and polypropylene glycol copolymers. They are delivered as oils, water solutions, or waterbased emulsions.

[0087] In an embodiment of the method, the water dispersible powder composition further comprises (kl) 1 - 7 wt.% of at least one precipitant. In an embodiment, the water dispersible powder composition comprises 2.5 - 5 wt.% of the at least one precipitant. In an embodiment, the water dispersible powder composition comprises 3 - 4.5 wt.% of the at least one precipitant. In an embodiment, the at least one precipitant is CaCO,.

[0088] For the sake of clarity, it is noted that the weight percentages as mentioned above and hereinbelow of all components (al)-(kl) are based on the total weight of the final water dispersible powder composition of the invention. In an embodiment of the method, the pH of the water dispersible powder composition is maintained in a range of [8, 11.5], in particular [9, 11.5]. In an embodiment, the pH of the water dispersible powder composition is maintained in a range of [10, 11]. The various components used are selected keeping in mind their influence on the pH.

[0089] In an embodiment of the method, the water dispersible powder composition further has a water content of 0-10 wt.%. In an embodiment, the water content is 0.1-2 wt.%. In an embodiment, the water content is 0.2-1.0 wt.%.

[0090] In an embodiment of the method, the water dispersible powder composition further comprises a biocide content of the powder is 0.0-0.01 wt.%. In an embodiment, the biocide content is 0.0-10'4wt.%. In an embodiment, the biocide content is 0.0-10'7wt.%. biocides are a chemical substance or microorganism intended to destroy, deter, render harmless, or exert a controlling effect on any harmful organism. Examples of biocides are for instance Zinc Pyrithione, and similar compounds. It should be noted, however, that preferably no biocides are used, or only trace amounts smaller than 10'7wt.%. The current water dispersible powder composition allows this.

[0091] In an embodiment of the method, the water dispersible powder composition further comprises a ratio of the at least one Calcium-Silicate-water (CSH) composition and the at least one pigment composition is between 1:6 and 6: 1 , in particular 1 :2.5 and 2.5-1, more in particular 1:1.5 and 1:4.

[0092] In an embodiment of the method, the at least one Calcium-Silicate-water (CSH) composition has a refractive index n > 1.5. In an embodiment, the at least one Calcium- Silicate-water (CSH) composition has a refractive index n>l,6.

[0093] In an embodiment, the at least one Calcium-Silicate-water (CSH) composition has a Mohs hardness of 3 - 6, the at least one Calcium-Silicate-water (CSH) composition has in particular 3-5.

[0094] In an embodiment of the method, the intimately mixing of the powders for obtaining the water dispersible powder composition of mixture is done for 2-40 minutes. In an embodiment, the mixing is done for 2-20 minutes. Examples of mixing devices are a Hosokawa Cyclomix, a Lodige Powder Turbo Mixer, and similar devices.

[0095] In an embodiment of the method, the water dispersible powder composition comprises less than 5 wt.% TiCh. In an embodiment of the method, the water dispersible powder composition comprises less than 2 wt.% TiCh. In an embodiment of the method, the water dispersible powder composition comprises less than 1 wt.% TiCh. In an embodiment of the method, the water dispersible powder composition comprises less than 0.5 wt.% TiCh, more particularly less than 0.01 wt.% of TiCh. The current water dispersible powder composition in particular allows a composition without TiCh.

[0096] It is noted that the water dispersible powder composition of the invention, preferably comprises less than 1 wt.% of white cement and / or portland cement, more preferably less than 0.5 wt.%, and most preferably less than 0.01 wt.% of white cement and / or portland cement. The term “portland cement” is well known in the art. It is a cement that sets under water and that is made by finely pulverizing the clinker produced by heating a mixture of clay and limestone or similar materials to a high temperature just short of fusing. White cement is a portland cement made from raw materials very low in the iron compounds that give the gray color to the usual portland cement),

[0097] In an embodiment, the water dispersible powder composition is granulated. In an embodiment, the granulate has a size of between 1-10 mm. In a particular embodiment, the granulate have a size of between 1 and 5 mm. The granulate size can be easily determined using a sieve.

[0098] The term “substantially” herein, such as in “substantially consists”, will be understood by the person skilled in the art. The term “substantially” may also include embodiments with “entirely”, “completely”, “all”, etc. Hence, in embodiments the adjective substantially may also be removed. Where applicable, the term “substantially” may also relate to 90% or higher, such as 95% or higher, especially 99% or higher, even more especially 99.5% or higher, including 100%. The term “comprise” includes also embodiments wherein the term “comprises” means “consists of’.

[0099] The term "functionally" will be understood by, and be clear to, a person skilled in the art. The term “substantially” as well as “functionally” may also include embodiments with “entirely”, “completely”, “all”, etc. Hence, in embodiments the adjective functionally may also be removed. When used, for instance in “functionally parallel”, a skilled person will understand that the adjective “functionally” includes the term substantially as explained above. Functionally in particular is to be understood to include a configuration of features that allows these features to function as if the adjective “functionally” was not present. The term “functionally” is intended to cover variations in the feature to which it refers, and which variations are such that in the functional use of the feature, possibly in combination with other features it relates to in the invention, that combination of features is able to operate or function. The word “functionally” as for instance used in “functionally parallel” is used to cover exactly parallel, but also the embodiments that are covered by the word “substantially” explained above. For instance, “functionally parallel” relates to embodiments that in operation function as if the parts are for instance parallel. This covers embodiments for which it is clear to a skilled person that it operates within its intended field of use as if it were parallel.

[0100] Furthermore, the terms first, second, third and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other sequences than described or illustrated herein.

[0101] It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. Use of the verb "to comprise" and its conjugations does not exclude the presence of elements or steps other than those stated in a claim. The article "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

[0102] The invention further pertains to a method or process comprising one or more of the characterising features described in the description and / or shown in the attached drawings.

[0103] The various aspects discussed in this patent can be combined in order to provide additional advantages. Furthermore, some of the features can form the basis for one or more divisional applications.

[0104] Examples and Comparative Examples

[0105] Below, various examples of the current method and water dispersible powder composition are presented. Example 1

[0106] The following components were used in the following amounts:

[0107] Raw Material Amount (wt.%) cation-metal oxide and / or hydroxide powder 10 water-dispersible polymer 24 co-solvent trace amount (below 0.1 wt.%)

[0108] Paint film strength improving material (b3) 20

[0109] Raux® 400V ex Mineraux 40.55

[0110] Hydrophobic additive 0.25

[0111] Rheology modifier 1.7

[0112] Wetting agent 0.3

[0113] Defoamer 0.7

[0114] Rupture-preventing material 2.5

[0115] The components above were introduced into a mixer. For lab-scale testing and preparation, a 7 litre Kenwood kitchen appliance with sealed openings was used. The components were mixed at a set speed of 200 rpm. The resulting composition was sieved with a mesh value of 40.

[0116] The particle size distribution was measured, resulting in D99 of 100 pm and D4,3 of 13.4 pm. The particle size distribution (PSD) is measured using a Malvern Mastisizer 3000 plus Hydro MV sample dispersion unit.

[0117] This resulted in a water dispersible powder composition. For performing the tests below, the water dispersible powder composition was mixed with regular tap water at a room temperature at a mixing ratio powder : water of 1 : 2 for 3 minutes. This resulted in a ready-to-use coating composition.

[0118] The coating composition was applied using a paint film applicator with a 200 pm opening on a Leneta opacity chart and on a Leneta wet scrub resistancy plastic film, 400 pm.

[0119] The following tests were done on the ready-to-use composition in agreement with ISO or European standards (EN)

[0120] Example 2

[0121] This water dispersible powder composition of the invention was prepared in the same manner as described in example 1 from the components as listed in Table 1.

[0122] The particle size distribution was measured, resulting in D99 of 100 pm and D4,3 of 13.4 pm.

[0123] Said water dispersible powder composition was mixed with regular tap water at a room temperature to form the ready-to-use coating composition.

[0124] The coating composition was applied using a paint film applicator with a 200 pm opening on a Leneta opacity chart and on a Leneta wet scrub resistancy plastic film, 400 pm.

[0125] The results are summarized in Table 1.

[0126] Comparative powder and coating compositions were prepared in a similar manner as described for examples 1 and 2, using the components as mentioned in Table 1. The experiments were carried out in the same manner as indicated above for example 2 and the results summarized in Table 1.

[0127] As follows from Table 1, the coating composition of the invention outperforms all other compositions in opacity characteristics. WSR (Wet Scrub Resistance) loss is also substantially better than for most other compositions.

[0128] able 1

[0129] Ex.02 Ex.03 Ex.06 Ex.07 Ex.08

[0130] (Invention) (Comparative) (Comparative) (Comparative) (Comparative) (Comparative) (Comparative

[0131] EVA powder 1) 21% 21% 21% 21% 21%

[0132] Acryllic powder 2) 21% 20%

[0133] Tobermorite powder 17% 17%

[0134] White p. cement (unhydrated) 17% 30%

[0135] Wollastonite (z=0) 17% 30%

[0136] Calcite 17% 17% 6%

[0137] Pigment composition 3) 56% 56% 56% 56% 56%

[0138] Fillers 4) 46%

[0139] TiO210% 10%

[0140] AlCaO42% 2% 2% 2% 2% 2%

[0141] Polycarboxylate 5) 2% 2% 2% 2% 2% 2% 2%

[0142] Wetting agent 6) 1% 1% 1% 1% 1% 1% 1%

[0143] Defoamer ?) 1% 1% 1% 1% 1% 1% 1%

[0144] Total 100% 100% 100% 100% 100% 100% 100%

[0145] Powder : Water ratio 2:1 1:1 2:1 1:1 2:1 2:1 1:1

[0146] Table 1 (cont.)

[0147] Opacity @ 8m2 / Lt 98.4 97.8 89.9 91.9 97.7 96.7 91.6

[0148] WSR loss |im 4.67 14.99 4.35 8.97 9.74 7.77 33.19

[0149] Yield point 220 492 47 56 38 54 176

[0150] Viscosity 1500 3900 115 50 926 62 2850

[0151] 1) Wacker Chemie, water-dispersible polyethylene vinyl acetate powder according to the invention

[0152] 2) Gerstaecker

[0153] 3) Mineraux - RAUX®400V, BaSO4 — based pigment composition according to the invention

[0154] 4) Talc, clay, bentonite, baryte

[0155] 5) Arkema - Ethacryl

[0156] 6) Miinzing - Agitan P840

[0157] 7) Miinzing - Metolat P590

[0158] The coating compositions of example 2 and comparative examples 4, 6, 7, and 8 were prepared by mixing the powder composition with water in a 2 : 1 ratio. The coating compositions of comparative examples 3 and 5 were prepared by mixing the powder composition with water in a 1 : 1 ratio, as otherwise these compositions were too thick to handle.

[0159] It will be clear that the above description is included to illustrate some embodiments of the invention, and not to limit the scope of protection. Starting from this disclosure, many more embodiments will be evident to a skilled person. These embodiments are within the scope of protection and the essence of this invention and are obvious combinations of prior art techniques and the disclosure of this patent.

Claims

Claims1. A method for producing a water dispersible powder composition for a paint comprising providing as powder components:(b) a binder, the binder comprising(bl) 1 - 20 wt.% of at least one powder, in particular 2 - 16 wt.%, more in particular 5 - 15 wt.%, selected from cation-metal oxide MO powders, cation-metal hydroxide MOH powders, and combinations thereof, in particular wherein the valence of the metal M is selected from2+and3+, and in particular wherein the cation is selected from Group 2 elements, more in particular from Ca, and Mg, and combinations thereof, and more in particular wherein the cation is selected from Al, Fe, and combinations thereof,(b2) 5 - 40 wt.% of at least one water-dispersible polymer, in particular 10 - 30 wt.% polymer, more in particular 15 - 21 wt.% polymer, in particular a hydrolysed polymer, more in particular selected from anionic polysaccharides, from polyvinyl alcohols, from acidic polymers, from a polystyrene sulphonates, from acidic biopolymers, from a pectin, from a carrageenan, from a gelatine, from polycarboxylic acid polymers, even more in particular from polyvinyl acetate, from polyethene-vinyl acetate, polyethylene-vinyl laurate, from copolymers thereof, and combinations thereof;(b3) 0 - 5 wt.% of at least one co-solvent, in particular 0.1 - 5 wt.%, more in particular 0.1 - 2 wt.%, in particular a co-solvent selected from co-solvents comprising at least one OH-moiety, and / or at least one COOH moiety, and / or at least one NH2 moiety, more in particular such as alcohols, alkanols, carboxylic acids, further comprising as powder components:(cl) 10 - 50 wt.% of a paint film strength improving material selected from at least one Calcium-Silicate -water (CSH; (CaO)x(SiO2)y(H2O))Z) composition, a calcium- alumino-silicate compound and a mixture thereof, in particular 10 - 30 wt.%, more in particular 15 - 21 wt.%, wherein the (CaO)x(SiO2)y(H2O))Zis selected from CSH compositions wherein x e [0.25, 0.75], in particular x e [0.4, 0.6], whereiny e [0.25, 0.75], in particular y e [0.4, 0.6], wherein z e [0.02, 0.5], in particular z e [0.02, 0.25],(dl) 5 - 60 wt.% of at least one pigment composition, in particular 30 - 60 wt%, and (el) 0 - 10 wt.% of at least one rupture preventing material comprising at least one fibre material, selected from natural fibers, in particular from lignin, cellulose, lignocellulose, hemicellulose, and a combination thereof, either as such, or in combination, wherein all wt.% are based on the total weight of the composition, therewith providing a powder mixture, and the method further comprising intimately mixing said powder mixture under a high shear, in particular at 20 - 9000 rpm, more in particular in a high shear mixer, more in particular a paddle mixer, therewith providing the water dispersible powder composition with a particle size distribution with D99 of between 30 and 200 pm, and D4,3 of 5 - 30 pm, wherein the particle size distribution is measured using a Malvern Mastisizer 3000 plus Hydro MV sample dispersion unit.

2. The method according to claim 1, wherein the at least one pigment composition (dl) comprises 0.5 - 60 wt.% of a BaSCfi - ZnS powder mixture in a weight ratio BaSCfi : ZnS of 1:10 to 10:1, in particular comprising 5 - 40 wt.% BaSCfi, more in particular 10 - 30 wt.% BaSCfi, even more in particular 18 - 25 wt.% BaSCfi, in particular comprising 5 - 40 wt.% ZnS, more in particular 10 - 30 wt.% ZnS, even more in particular 17 - 24 wt.% ZnS.

3. The method according to claim 1 or 2, comprising 1 - 10 wt.% of said at least one rupture preventing material (el) with said at least one rupture preventing material providing the fibre material, in particular 2 - 7 wt.%, more in particular 2 - 5 wt.%, in particular wherein the fibres have a length of 10 - 200 pm, more in particular the fibres have a length of 10 - 100 pm, more in particular wherein the fibre material is plant based, more in particular selected from cotton, hemp, wood, annual plants, algae and a combination thereof.

4. The method according to any one of the preceding claims, wherein the metal M in the powder of (bl) is selected from Group 3 elements, from Group 8 elements, andcombinations thereof, in particular from Fe, and Al, and combinations thereof.

5. The method according to any one of the preceding claims, wherein the CSH is selected from 9AT Tobermorite, 10AT Tobermorite, 11AT Tobermorite, 14AT Tobermorite, a-CSH, Afwillit, Bultfonteinit, Dellait, Foshagit, Gyrolit, Hillebrandit, Jaffeit, Jennit, Killalait, Klinotobermorit, K-phase, Okenit, Reyerit, Rheinhardtbraunsit, Truscottit, Xonotlite, Z-phase, and combinations thereof.

6. The method according to any one of the preceding claims, further comprising (fl) 0.25 - 3.0 wt.% of at least one rheology modifier, in particular 0.5 - 2.5 wt.%, more in particular 0.5 - 2.5 wt.% of at least one super plasticizer, in particular 0.8 - 2.0 wt.%, more in particular 1.0 - 2.0 wt.%, and / or(gl) 0.05-2.0 wt.% of at least one hydrophobic additive, in particular 0.2 - 1.0 wt.%, more in particular 0.25-0.5 wt.%, and / or(hl) 0.05-1.0 wt.% of at least one wetting agent, in particular 0.1 - 0.5 wt.%, more in particular 0.2-0.4 wt.%, and / or(jl) 0.25-2.0 wt.% of at least one defoamer, in particular 0.5 - 1.5 wt.%, more in particular 0.65-0.8 wt.%, and / or(kl) 1-7 wt.% of at least one precipitant, in particular 2.5 -5 wt.%, more in particular 3-4.5 wt.%, in particular comprising CaCCh, and / or wherein the pH of the powder composition is maintained in a range of in particular [8, 11.5], in particular [10, 11], and / or wherein a water content of the powder is 0-10 wt.%, in particular 0.1-1 wt.%, such as 0.2-0.5 wt.%, and / or wherein a biocide content of the powder is 0.0-0.01 wt.%, in particular 0.0-10'4wt.%, such as 0.0-10'7wt.%.

7. The method according to any one of the preceding claims, wherein a ratio of the at least one Calcium-Silicate-water (CSH) composition and the at least one pigment composition is between 1:6 and 6:1 , in particular 1:2.5 and 2.5-1, more in particular 1:1.5 and 1:4.

8. The method according to any one of the preceding claims, wherein the at least one Calcium-Silicate -water (CSH) composition has a refractive index n > 1.5, in particular n>l,6, and / or wherein the at least one Calcium-Silicate-water (CSH) composition has a Mohs hardness of 3 - 6, in particular 3-5.

9. The method according to any one of the preceding claims, wherein the intimately mixing said powder mixture is done for 2-40 minutes, in particular 2-20 minutes.

10. The method according to any one of the preceding claims, comprising less than 5 wt.% TiCh, in particular less than 2 wt.%, in particular less than 1 wt.%, more in particular less than 0.5 wt.%, even more in particular less than 0.01 wt% of TiCh11. The method according to any one of the preceding claims, wherein the water dispersible powder composition is granulated, in particular to provide a granulate having a size of between 1-10 mm, in particular between 1 and 5 mm.

12. Method for providing a paint for application onto a surface, comprising providing 2 weight parts of the water dispersible powder composition of any one claims 1-10, and 0.5 - 2 weight parts of water, in particular 0.8 - 1.2 weight parts of water, more in particular 0.9 - 1.1 weight parts of water, mixing the water dispersible powder composition with water, therewith forming a paint, and applying the paint onto the surface, in particular applying the paint within 36 hours, in particular within 24 hours, and most in particular within 2 hours after mixing with water, more in particular wherein the surface is selected from a wall, from a ceiling, such as from a brick surface, from a concrete surface, from a cement, and from a plaster.

13. A wall paint powder composition comprising the water dispersible powder composition obtained using the method of any one of claims 1-11.

14. A paint composition obtainable by mixing the water dispersible powder composition from the method according to any one of the preceding claims 1-11 with water, in particular in a weight ratio powder : water of between 1:3 and 3:1 for providing a water based coating composition, in particular a wall paint.

15. A granulate produced using the water dispersible powder composition obtained using the method of any one of the preceding claims 1-11, in particular having a size of 1-10 mm, more in particular of 1-5 mm.-o-o-o-o-o-

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