Dispersible wax particles

Abstract

The present invention relates to a micronized wax composition, to a process for the preparation thereof, to the use thereof for the preparation of an aqueous formulation, to an aqueous formulation comprising a micronized wax composition and to a process for the preparation of an aqueous formulation.

Description

Technical Field

[0001] The present invention relates to dispersible wax particles and micronized wax compositions, their use for preparing aqueous preparations, aqueous preparations containing the micronized wax compositions and methods for preparing the aqueous preparations. Background Art

[0002] Waxes and their derivatives are used in many areas of industry and the home, in particular in personal care products, for example in cosmetics and hair care products, in care products for floors, furniture, clothing, shoes and cars, in medicine and food, for example as gloss agents, and in the production of plastic compositions, (hot-melt) adhesives, printing inks, lacquers and other preparations.

[0003] DE 10 2013007638 describes a process for preparing acid waxes from mixtures of natural waxes and polyolefin waxes and their use in soaps and shoe polishes.

[0004] DE 102018116113 discloses oxidized natural waxes which are used, inter alia, for shoe care products, car care products, floor care products, furniture care products, industrial release agents, coating agents, hydrophobizing agents, adhesives, cosmetic compositions, as production aids in plastics processing and as release agents or gloss agents for confectionery and chewing gum.

[0005] Liquid wax dispersions are used, inter alia, for the preparation of paints, printing inks and other coatings.However, organic solvents, which are disadvantageous from an economic and ecological point of view and are often a concern for human and animal health, are often used as dispersion media.

[0006] EP-A 2970700 describes coating systems which contain chemically unmodified cellulose, polyolefin waxes and / or Fischer-Tropsch waxes and / or amide waxes and / or biobased waxes and further components.

[0007] The lacquer system has good scratch resistance and can be redispersed in butyl acetate when the lacquer components have settled. However, many of the described formulations contain organic solvents.

[0008] Due to the disadvantages associated with the use of organic solvents, aqueous wax dispersions are becoming increasingly important since they represent a more cost-effective, more environmentally friendly and less toxic alternative to solvent-containing dispersions.

[0009] WO 2006 / 131147 shows a composition for water-based inks comprising a biocide and a wax or paraffin. The composition is prepared by melting the wax in an aqueous biocide solution at 80 to 85° C., then adding casein as a thickener and a surfactant to the mixture, with care being taken to prevent agglomeration. The resulting formulation is added to an acrylic lacquer. Due to the elevated temperatures and the multi-step process, the preparation of the wax dispersion is complicated for an inexperienced user and difficult to carry out without the required expertise.

[0010] DE4330342 (BASF) discloses an aqueous polyolefin wax dispersion containing polyethylene wax or polypropylene wax and a mainly unsaturated C 16-22 Glycerol esters of monocarboxylic acids reacted with 1,2-olefin oxides. These dispersions are prepared by incorporating a micronized wax into a solution of the dispersant in demineralized water.

[0011] Finished wax dispersions can be sold commercially and provided to the user already in a ready-to-use form. However, this generally has the disadvantage that, due to the high water content, significantly larger volumes must be transported and stored than if the wax were sold in solid form and dispersed by the user shortly before use. At the same time, the durability of aqueous wax dispersions is generally poorer than that of solid waxes, and the stability of the dispersions is generally limited, so that the dispersions provided should be used shortly after they are obtained.

[0012] There is therefore a need for waxes which can be easily dispersed in water or in aqueous preparations such as water-based paints and printing inks.

[0013] Easily dispersible wax particles can make it possible for the user to prepare aqueous wax dispersions on site at his own facilities and use them immediately. This can reduce transportation and storage costs, in particular, since only solid wax needs to be obtained.

[0014] DE 10 2004059060 discloses the preparation and use of lipophilic waxes which can be easily incorporated into oil-based inks and varnishes. Dispersibility in water is not mentioned.

[0015] DE 19620810 describes mixtures of unfunctionalized polyethylene wax or polypropylene wax particles with certain hydrophilic dispersants, which are present in particular in the form of free-flowing powders and are intended for subsequent preparation of aqueous wax dispersions. The powder is an unfunctionalized polyolefin wax having mainly unsaturated C 16-22A mixture of glycerol esters of monocarboxylic acids which may additionally contain hydroxyl groups reacted with 1,2-olefin oxides. The mixing is carried out without addition of water. The product obtained is said to be a free-flowing powder which can be incorporated with addition of water. The conditions for preparing the dispersion are not disclosed. The process requires specific dispersants which are not necessarily suitable for every application and some end users may not necessarily have knowledge of the preparation of wax dispersions.

[0016] US2016018334 discloses the use of O / W emulsions prepared according to the PIT method for lubricating conveyor belts in the food industry. Therefore, neither micronized wax additives nor dispersions prepared by dry comminution of wax are disclosed.

[0017] Documents US 5746812 and WO 2012022389 describe wax dispersions containing micronized wax. Dry comminution of wax together with an emulsifier is not described anywhere in these documents.

[0018] US20090294971 describes The dispersed wax is pulverized in the processor with the aid of an emulsifier to obtain a more stable dispersion. Neither the dry pulverization process nor the product obtained by the dry pulverization process is disclosed.

[0019] Jian et al., J. Appl. Polymer Sc., 12.12.2012, 1476-1483, describe polyethylene wax (PEW) microspheres prepared by a solution precipitation method using PEW byproducts as starting materials. Neither the dry pulverization method nor the products obtained by the dry pulverization method are disclosed.

[0020] DE 10 2015226240 describes rice bran waxes bleached with oxygen-containing gases and simultaneously polar-modified. These waxes have the advantage that they can be dispersed better in water and polar solvents than unmodified rice waxes. However, dispersing such modified waxes requires some knowledge and experience, which may not be available to some end users.

[0021] Therefore, there still exists a need for dispersible wax compositions which can be dispersed quickly and without great expenditure in water and aqueous preparations such as water-based paints and printing inks, thereby allowing even inexperienced end users to prepare wax dispersions and allowing the finished products to be easily modified by mixing the compositions. Summary of the invention

[0022] It has now surprisingly been found that by dry comminution of wax in the presence of at least one emulsifier a micronized wax composition is obtained which can be rapidly dispersed in water and water-based preparations, for example by stirring, vibrating or even shaking. The dispersion speed, avoidance of agglomerates and stability of the dispersion obtained are surprisingly significantly better than when mixing of the wax with the emulsifier is already done after comminution. In paints and coatings, the micronized wax composition leads to good scratch resistance. The micronized wax composition further exhibits good free flowability.

[0023] The subject of the present invention is therefore a process for preparing a micronized wax composition (C), comprising the following steps:

[0024] In the presence of at least one emulsifier (E), preferably in liquid or dissolved form, and optionally at a density of >1 g / cm at 20° C. 3 Dry comminuting at least one wax (W) in the presence of at least one density additive (D) of at least one wax (W), wherein the density additive (D) is substantially insoluble in water at 20° C., and optionally in the presence of at least one further additive (A) which is different from the at least one wax (W), the at least one emulsifier (E) and the at least one density additive (D).

[0025] Comminution means dividing a solid material into smaller parts by the action of mechanical forces. Most comminution equipment is configured for dry comminution. Comminution from a paste to a liquid dispersion is called wet comminution (see 9th edition).

[0026] Dry comminution can result in warming of the particles to be comminuted. If the warming is too strong, cooling can be carried out with water. However, this comminution under cooling is not equivalent to wet comminution, because the amount of water is kept low enough not to change the product properties. If the dry comminution is carried out in a mill, the emulsifier (E) is metered into the grinding chamber during the grinding of the wax (W) by volume or weight metering.

[0027] In the sense of the present invention, the melting of solid wax with subsequent comminution by spraying in a spray tower is also referred to as dry comminution.

[0028] "Dissolved form" means that the emulsifier is present in a highly concentrated form in the solvent, i.e. the solvent is used precisely so that the required amount of emulsifier can be completely dissolved and the emulsifier can be sprayed or pumped. However, the amount of solvent should not exceed more than 30% of the amount of solvent required for complete dissolution.

[0029] This limitation of the amount of solvent is necessary so as not to obtain the micronized wax composition (C) as a solid / solvent mixture (dispersion), ensuring the coating of the wax particles with the emulsifier, thus maintaining the advantageous properties of the micronized wax composition.

[0030] Preferably, less than 20% by weight, particularly preferably less than 10% by weight and very particularly preferably less than 5% by weight of water is used in the dry comminution, based on the total amount of wax used for comminution.

[0031] Another subject of the present invention is a micronized wax composition (C) comprising:

[0032] a) at least one wax (W);

[0033] b) at least one emulsifier (E);

[0034] c) optionally at least one density additive (D) having a density of >1 g / cm at 20°C 3 , preferably >1.3g / cm 3 , wherein the density additive (D) is substantially insoluble in water at 20° C.; and

[0035] d) optionally at least one further additive (A) which is different from the at least one wax (W), the at least one emulsifier (E) and the at least one density additive (D),

[0036] Therein the micronized wax composition (C) is obtained by dry comminuting at least one wax (W) in the presence of at least one emulsifier (E), preferably in liquid or dissolved form, and optionally in the presence of at least one density additive (D) and / or at least one further additive (A).

[0037] Preferably, the water content of the micronized wax composition (C) is less than 20% by weight, particularly preferably less than 10% by weight, very particularly preferably less than 5% by weight, based on the total weight of the micronized wax composition (C). The water content is determined using a halogen moisture analyzer HR73 from Mettler Toledo by analyzing a predetermined amount (between 2 and 7 g) of sample at 105° C. (accuracy ±0.0001 g). The measurement is carried out according to the manufacturer's presettings. If the weight loss after 90 seconds is less than 1 mg, the measurement is terminated after this time and the water content is determined.

[0038] Preferably, the micronized wax composition consists of these components.Thus, the wax composition (C) according to the invention is obtainable by the process according to the invention.

[0039] The expression "substantially insoluble in water at 20°C" means that at most 20 g, preferably at most 10 g, more preferably at most 5 g, more preferably at most 1 g of the density additive (D) can be dissolved in 1 L of water at 20°C.

[0040] The expression "micronized" in this context means that the (average) particle size of the substance in question has been reduced compared to the starting state and less than 1% by volume of the particles have a particle size of 1000 μm or more.

[0041] The particle size distribution can be measured, for example, by laser diffraction, as described, for example, in "A Guidebook to Particle Size Analysis" (Horiba Instruments, Inc., 2019). Suitable measuring instruments for this are, for example, the LA-960 from Horiba Instruments, Inc., which can measure particle sizes in the range of 10 nm to 5 mm, or the Mastersizer 3000 from Malvern Panalytical, which can measure particle sizes in the range of 10 nm to 3.5 mm.

[0042] Preferably, the micronized wax composition (C) comprises:

[0043] a) 40 to 99.9 wt. %, preferably 50 to 99 wt. %, more preferably 60 to 98.8 wt. %, more preferably 65 to 98.5 wt. %, more preferably 70 to 98 wt. % of at least one wax (W), based on the weight of the micronized wax composition (C);

[0044] b) 0.1 to 20 wt. %, preferably 1 to 15 wt. %, more preferably 1.2 to 8 wt. %, more preferably 1.5 to 5 wt. %, more preferably 2 to 4 wt. % of at least one emulsifier (E), based on the weight of the micronized wax composition (C);

[0045] c) optionally, 0 to 59.9 wt. %, preferably 0 to 45 wt. %, more preferably 0 to 38 wt. %, more preferably 0 to 30 wt. %, more preferably 0 to 26 wt. %, based on the weight of the micronized wax composition (C), of at least one density additive (D); and

[0046] d) optionally 0 to 50 wt. %, preferably 0 to 45 wt. %, more preferably 0 to 38 wt. %, more preferably 0 to 30 wt. %, more preferably 0 to 26 wt. %, based on the weight of the micronized wax composition (C), of at least one further additive (A).

[0047] Preferably, the sum of a), b), c) and d) is 100% by weight of the micronized wax composition (C), so that the micronized wax composition (C) consists of at least one wax (W), at least one emulsifier (E), optionally at least one density additive (D) and optionally at least one further additive (A).

[0048] When at least one density additive (D) is included, its amount is typically at least 0.1 wt%, preferably at least 1 wt%, more preferably at least 5 wt%, based on the weight of the micronized wax composition (C). In these cases, the upper limit of the amount of wax (W) is adjusted accordingly so that the sum of the components does not exceed 100 wt%.

[0049] When at least one additional additive (A) is included, its amount is typically at least 0.01 wt.-%, preferably at least 0.1 wt.-%, more preferably at least 1 wt.-%, based on the weight of the micronized wax composition (C). In these cases, the upper limit of the amount of wax (W) is adjusted accordingly so that the sum of the components does not exceed 100 wt.-%.

[0050] Another subject of the present invention is an aqueous preparation comprising water and 0.01 to 60% by weight, preferably 0.1 to 50% by weight, more preferably 0.2 to 4% by weight or 30 to 40% by weight, more preferably 0.3 to 3% by weight or 32 to 38% by weight of a micronized wax composition (C), based on the total weight of the aqueous preparation, wherein the micronized wax composition (C) is dispersed in the water.

[0051] Furthermore, the subject of the present invention is a process for preparing a water-based formulation comprising the following steps:

[0052] i) providing water, a micronized wax composition (C) and optionally further components;

[0053] ii) mixing the components provided in step i), preferably by stirring, vibrating or shaking.

[0054] The present invention also provides for the use of the micronized wax composition (C) for preparing aqueous preparations and for the use of the micronized wax composition (C) according to the invention and / or of the wax concentrates obtained therefrom for improving the scratch resistance of coatings or lacquers produced from ready-to-use aqueous preparations.

[0055] The micronized wax composition (C) according to the invention and its components used in the process according to the invention are described in more detail below.

[0056] Wax (W)

[0057] The wax (W) contained in the micronized wax composition (C) can in principle be any wax. For example, the wax (W) can be selected from the group consisting of synthetic organic waxes, partially synthetic organic waxes, natural waxes (bio-based waxes) and mixtures thereof, wherein the wax can optionally be oxidized or otherwise chemically modified.

[0058] As wax components, synthetic hydrocarbon waxes, for example polyolefin waxes, are suitable. These can be prepared by thermal decomposition of branched or unbranched polyolefin plastics or by direct polymerization of olefins. As polymerization methods, for example free radical methods are considered, in which olefins, usually ethylene, are converted into more or less branched polymer chains under high pressure and temperature; in addition, methods are considered in which ethylene and / or higher 1-olefins, for example propylene, 1-butene, 1-hexene, etc. are polymerized to unbranched or branched waxes by means of organometallic catalysts, for example Ziegler-Natta or metallocene catalysts.

[0059] Corresponding processes for preparing olefin homopolymer waxes and olefin copolymer waxes are described, for example, in Ullmann's Encyclopedia of Industrial Chemistry, 5th edition, Volume A 28, Weinheim 1996, Chapters 6.1.1. / 6.1.2. (High-pressure polymerization (waxes), Chapter 6.1.2. (Ziegler-Natta polymerization, polymerization with metallocene catalysts) and Chapter 6.1.4. (Thermal decomposition).

[0060] Furthermore, so-called Fischer-Tropsch waxes can be used. These are prepared catalytically using synthesis gas and differ from polyethylene waxes by having a lower average molar mass, a narrower molar mass distribution and a lower melt viscosity.

[0061] The hydrocarbon waxes used can be unfunctionalized or functionalized by polar groups.

[0062] Such polar functionalities can be introduced subsequently by corresponding modification of nonpolar waxes, for example by oxidation with air or by grafting polar olefin monomers, for example α,β-unsaturated carboxylic acids and / or derivatives thereof, such as acrylic acid or maleic anhydride. In addition, polar waxes can be prepared by copolymerization of ethylene with polar comonomers, for example vinyl acetate or acrylic acid; furthermore by oxidative decomposition of higher molecular weight non-wax ethylene homopolymers and ethylene copolymers. Corresponding examples can be found, for example, in Ullmann's Encyclopedia of Industrial Chemistry, Fifth Edition, Volume A 28, 1996, Chapter 6.1.5.

[0063] Suitable polar waxes are also amide waxes, obtainable, for example, by reacting long-chain carboxylic acids, for example fatty acids, with monofunctional or polyfunctional amines. The fatty acids typically used for this purpose have a chain length in the range of between 12 and 24, preferably between 16 and 22 C atoms, and may be saturated or unsaturated. Fatty acids preferably used are C16-acids and C18-acids, in particular palmitic acid and stearic acid or a mixture of the two acids. Amines come into consideration, in addition to ammonia, particularly polyfunctional, for example difunctional organic amines, of which ethylenediamine is preferred. Particularly preferably, waxes prepared from technical stearic acid and ethylenediamine under the commercially common name EBS wax (ethylene bis stearyl diamide) are used.

[0064] In addition, bio-based waxes can be used, wherein it is generally ester waxes. Generally, bio-based waxes are understood to be those waxes based on renewable raw materials. In this case, it can be either natural or chemically modified ester waxes. Typical natural bio-based waxes are described in Ullmann's Encyclopedia of Industrial Chemistry, the fifth edition, A 28 volumes, 1996, in the 2nd chapter. Among them include palm wax such as carnauba wax, grass wax such as candelilla wax, sugarcane wax and straw wax, beeswax, rice wax, etc. Chemically modified waxes are generally produced by ester wax or vegetable oil-based fatty acids through oxidation (for example, by CrO3 and H2SO4 mixture), esterification, transesterification, amidation, hydrogenation, etc. These examples also include metathesis products of vegetable oils.

[0065] Bio-based waxes furthermore include montan waxes in unmodified or refined or derivatized form. Details of waxes of this type are found, for example, in Ullmann's Encyclopedia of Industrial Chemistry, 5th edition, volume A 28, 1996, chapter 3 (waxes).

[0066] Before dry comminution, the wax (W) may have any particle size. For example, the wax (W) may be a granular material having a particle size of >1 mm, such as 2 to 10 mm. However, before dry comminution, the wax (W) may also have a particle size of ≤1 mm, such as 200 to 900 μm.

[0067] The micronized wax composition (C) according to the invention also has good dispersibility in water and in water-based formulations such as water-based paints and printing inks, even if the wax (W) itself does not substantially form a stable dispersion in water. Therefore, functional groups that can improve the dispersibility of the wax are not necessary. However, the wax (W) can also contain functional groups that influence certain properties of the wax.

[0068] Thus, in one embodiment, the wax (W) does not substantially form a stable dispersion in water. In the present context, this is the case when, after incorporation of the wax (W) in water at 20° C. (about 10% by weight of wax) in the absence of an emulsifier, a visible phase separation occurs within 1 hour at a stirring speed of 700 rpm for 5 minutes with a laboratory blade stirrer.

[0069] In such an embodiment, the wax (W) is preferably not oxidized and is not grafted or copolymerized with heteroatom-containing groups. Preferably, the wax (W) in this embodiment does not contain polar groups.

[0070] Although oxidation and grafting can have a positive effect on the dispersibility of the wax (W) in water and water-based formulations, other properties of the wax can also be negatively influenced here. This embodiment is usually relevant in the case of synthetic or partially synthetic waxes, especially in the case of polyolefin waxes, whose properties are usually adjusted by the selected synthesis conditions and where a change in these properties is undesirable.

[0071] Preferably, such waxes (W) have an acid number (measured according to DIN EN ISO 2114:2000) and preferably a saponification number (measured according to DIN EN ISO 3681:2018) and / or a hydroxyl number (measured according to DIN EN ISO 2554:1997) of in each case 0 to 40 mg KOH / g, preferably 0 to 20 mg KOH / g, more preferably 0 to 10 mg KOH / g. The polyolefin waxes can be prepared especially by Ziegler-Natta catalysis or by metallocene catalysis, preferably metallocene catalysis, and preferably have an acid number of 0 to 5 mg KOH / g.

[0072] Typically, the wax can be selected from polyolefin waxes, mineral waxes, montan waxes, rice bran waxes, beeswax, sunflower waxes, corn waxes, carnauba waxes, Fischer-Tropsch waxes, paraffin waxes, ester waxes and amide waxes. Preferably, the wax is selected from polyethylene waxes, polypropylene waxes, poly(ethylene-to-propylene) waxes, rice bran waxes, corn waxes and sunflower waxes, and more preferably, the wax is HDPE wax (high density polyethylene).

[0073] Micronized wax compositions (C) in which the pure wax (W) contains polar groups also have significantly improved dispersibility. Therefore, in another embodiment, the wax (W) may contain polar groups and may preferably be oxidized, grafted with heteroatom-containing groups or chemically modified in other ways.

[0074] Oxidation is also particularly relevant for natural waxes, especially montan wax, rice wax, sunflower wax, corn wax and carnauba wax, since these waxes are usually dark in the raw state and can be bleached, for example, by oxidation. In the case of waxes (W) containing polar groups, for example in the case of oxidized natural waxes, the acid number is generally more than 15 mg KOH / g, preferably between 20 and 200 mg KOH / g.

[0075] For example, the acid number may be in the range of 45 to 70 mg KOH / g or in the range of 70 to 170 mg KOH / g.Such waxes may also be further derivatized, for example by esterification, amidation or saponification.

[0076] However, the wax (W) may also be derivatized in other ways before micronization. For example, a wax, preferably a polyolefin wax, may be grafted with heteroatom-containing groups. These include, for example, waxes grafted with carboxylic acid derivatives having ethylenically unsaturated groups. Preferably, such a derivatized wax is grafted with a heteroatom-containing group selected from the group consisting of acrylic acid, alkyl acrylates, acrylamide, methacrylic acid, alkyl methacrylates, methacrylamide, maleic acid, alkyl maleates, maleic anhydride and maleimide, more preferably maleic acid, maleic anhydride and maleimide, more preferably maleic anhydride. The wax grafted with these groups is preferably a polyethylene wax, a polypropylene wax or a poly(ethylene-co-propylene) wax, more preferably a polyethylene wax or a polypropylene wax, more preferably a HDPE wax.

[0077] Preferably, the wax (W) is a polyolefin wax having a dropping point (measured according to DIN ISO 2176:1995) in the range of 100 to 160° C., more preferably in the range of 110 to 150° C., more preferably 120 to 145° C., more preferably 125 to 135° C., and a viscosity in the range of 0.88 to 1.06 g / cm 3 In the range of 0.90 to 1.02 g / cm 3 In the range of 0.90 to 1.00 g / cm 3 In the range of 0.90 to 0.98 g / cm 3 Density within the range.

[0078] Emulsifier (E)

[0079] The emulsifier (E) may be any emulsifier which can improve the dispersibility of non-polar solids in polar media, especially water. As emulsifiers, suitable are nonionic, anionic, cationic and amphoteric surfactants.

[0080] Suitable nonionic surfactants include, for example, fatty alcohol alkoxylates (which may optionally be alkyl-terminated), fatty acid alkoxylates (which may optionally be alkyl-terminated), alkyl glucosides, alkyl polyglucosides, alkylphenol ethoxylates, fatty acid esters of polyglycerols and alkoxylated fatty acid glycerides. Preferred nonionic surfactants are C8-C 30 Fatty alcohol alkoxylates and C8-C 30 Fatty acid alkoxylates having 1 to 100, preferably 2 to 50, more preferably 3 to 10 alkylene oxide units, preferably ethylene oxide units and / or propylene oxide units, more preferably ethylene oxide units.

[0081] Suitable anionic surfactants include, for example, fatty acid salts, alkylbenzenesulfonates, alkylsulfonates, fatty alcohol sulfates, alkyl ether sulfates, sulfoacetates and taurine. Preferred anionic surfactants are alkali metal salts of C8-C30 fatty acids, alkali metal salts of C8-C30 alkylbenzenesulfonic acids and alkali metal salts of C8-C30 alkylsulfonic acids.

[0082] Suitable cationic surfactants are, for example, quaternary ammonium salts, preferably halides, more preferably chlorides, such as quaternary ammonium salts having 1, 2 or 3 C8-C 30 tetraalkylammonium salts of C1-C4 alkyl residues and 3, 2 or 1 C1-C4 alkyl residues, and quaternary ammonium salts of alkanolamine fatty acid esters (esterquats). Preferred cationic surfactants are C8-C 30 Alkyl trimethyl ammonium salt, di(C8-C 30 Alkyl) dimethyl ammonium salts and based on C8-C 30 Esterquats of quaternized triethanolamine esters of fatty acids.

[0083] Suitable amphoteric surfactants include, for example, those containing long-chain alkyl groups, preferably C5-C 30 Betaine derivatives containing C5-C6 alkyl groups and betaine derivatives containing C5-C6 alkyl groups 30 Alkyl group sulfobetaines.

[0084] Preferably, the emulsifier (E) is a nonionic emulsifier, such as a nonionic surfactant. More preferably, the emulsifier (E) is a nonionic emulsifier that is liquid at 20°C or soluble in water at 20°C.

[0085] The properties of nonionic emulsifiers can be described, for example, by the mass ratio between the polar part and the nonpolar part of the surfactant and defined by the HLB value ("hydrophile-lipophile balance", the hydrophile-lipophile ratio of the molecule). The extent of this hydrophile-lipophile ratio can be determined by calculating the values ​​of different regions of the molecule, as described by Griffin (see, for example, Journal of the Society of Cosmetic Chemists, 5(4), 249-256 (1954)). The Griffin method was developed primarily for nonionic surfactants; the calculation of the HLB value is given by the following formula:

[0086] HLB=20*Mh / M,

[0087] Where Mh is the molecular mass of the hydrophilic part of the molecule and M is the molecular mass of the entire molecule, this results in a value on a scale from 0 to 20 being given.

[0088] An HLB value of 0 corresponds to a completely lipophilic molecule, and an HLB value of 20 corresponds to a completely hydrophilic molecule.

[0089] The emulsifier (E) used in the process according to the invention and contained in the wax composition (C) is preferably a nonionic emulsifier having an HLB value in the range of 6 to 16, preferably 7 to 15, more preferably 9 to 13, more preferably 10 to 12.

[0090] The micronized wax composition (C) preferably contains the emulsifier (E) in an amount of 0.1 to 20 wt %, more preferably 1 to 15 wt %, more preferably 1.2 to 8 wt %, more preferably 1.5 to 5 wt %, more preferably 2 to 4 wt %, based on the weight of the micronized wax composition (C).

[0091] Optional density additive (D)

[0092] Optionally, the micronized wax composition (C) may contain a density additive (D) having a density of >1 g / cm at 20°C. 3 , preferably >1.1 g / cm 3 , more preferably 1.2 to 10.0 g / cm 3 , more preferably 1.3 to 5 g / cm 3 , more preferably 1.4 to 4.8 g / cm 3 density.

[0093] The density additive (D), when present, serves to increase the density of the micronized wax composition (C) so that it does not float as much as possible on the aqueous phase when dispersed in water. For this reason, the density additive (D) must be substantially insoluble in water at 20° C. Additives that are well soluble in water would increase the density of the aqueous phase and thus exert the opposite effect.

[0094] The amount of density additive (D) in the micronized wax composition (C) is preferably selected so that the density of the micronized wax composition (C) is approximately equal to or slightly higher than the density of water. If the micronized wax composition (C) is intended to be dispersed in an aqueous solution having a density higher or lower than that of pure water, the amount of density additive (D) may also be selected so that the density of the micronized wax composition (C) is approximately equal to or slightly higher than the density of the aqueous solution.

[0095] Preferably, the amount of density additive (D) in the micronized wax composition (C) is selected so that the density of the micronized wax composition (C) at 20° C. is between 0.94 and 1.20 g / cm 3 , preferably 0.96 to 1.10 g / cm 3 , more preferably 0.98 to 1.06 g / cm 3 , more preferably 1.00 to 1.04 g / cm 3 within the range.

[0096] The density additive (D) may be an organic additive or an inorganic additive.

[0097] The organic density additive (D) may have a density of, for example, 1.1 to 2.8 g / cm 3 , preferably a density in the range of 1.3 to 2.5. Suitable organic density additives (D) include, in particular, halogenated organic polymers such as polyvinyl chloride, polyvinylidene chloride, polyvinyl fluoride, polyvinylidene fluoride and polytetrafluoroethylene (PTFE), polyamides and aromatic polyamides, and polysaccharides or polyglucosides such as cellulose, hemicellulose, starch, chitin, chitosan, etc. Preferred organic density additives (D) are PTFE wax and cellulose, more preferably PTFE wax.

[0098] The inorganic density additive (D) may, for example, have a density of 2.0 to 10.0 g / cm 3 , preferably 2.1 to 5.0 g / cm 3 , more preferably 2.5 to 4.8 g / cm 3 The density of the present invention is preferably within a range of 100 to 200 ℃. Suitable inorganic density additives (D) include, in particular, substantially insoluble inorganic salts and minerals. Examples of suitable inorganic density additives (D) are silicon dioxide, magnesium carbonate, magnesium fluoride, calcium carbonate, calcium sulfate, calcium fluoride, strontium carbonate, strontium sulfate, strontium fluoride, barium carbonate, barium sulfate and barium fluoride. Preferred inorganic density additives (D) are sparingly soluble salts of alkaline earth metals, more preferably calcium sulfate, calcium carbonate, barium sulfate or barium carbonate, more preferably calcium carbonate.

[0099] Optional additional additives (A)

[0100] Optionally, the micronized wax composition (C) may comprise at least one further additive (A) which is different from the at least one wax (W), the at least one emulsifier (E) and the at least one density additive (D).

[0101] The further additive (A) may be any additive which does not substantially affect the dispersibility of the micronized wax composition (C) in water. For example, the further additive (A) may comprise conventional wax additives which increase the stability of the wax against external influences.

[0102] Suitable additional additives (A) include, for example, antioxidants, UV stabilizers, heat stabilizers, plasticizers, wetting aids, defoamers, processing aids, thixotropic agents, gelling agents, thickeners, release agents, flow aids, fragrances, biocides, dyes and pigments. In this context, solvent residues, such as water, are also included in the additional additives (A). For example, if at least one emulsifier (E) or another additive (A) is used in dissolved form, these may be contained.

[0103] If present, the further additives (A) are used in the amounts customary for such additives. For example, the further additives (A) may be present in a total amount of 0.01 to 50 wt.-%, preferably 0.05 to 45 wt.-%, more preferably 0.1 to 38 wt.-%, more preferably 0.1 to 30 wt.-%, more preferably 0.1 to 26 wt.-%, based on the weight of the micronized wax composition (C).

[0104] Process for preparing micronized wax composition (C)

[0105] The micronized wax composition (C) is obtained by dry comminution of at least one wax (W) in the presence of at least one emulsifier (E).

[0106] If present, the optional density additive (D) and / or the optional further additive (A) may likewise be present during the dry comminution or may be mixed with the micronized wax composition only after the dry comminution. Preferably, at least the optional density additive (D) and more preferably also the optional further additive (A) are present during the dry comminution of the wax (W).

[0107] In the dry comminution of at least one wax (W), at least one emulsifier (E) can be present in solid, liquid or dissolved form. When the emulsifier is present in solid form, the wax (W) is typically dry mixed with the emulsifier (E) and subsequently comminuted with it, or the solid emulsifier (E) is metered into the grinding chamber during the grinding of the wax (W) by volumetric or weight metering.

[0108] Preferably, however, at least one emulsifier (E) is in liquid or dissolved form during dry comminution of the at least one wax (W). This generally leads to even better dispersibility of the resulting micronized wax composition (C).

[0109] This means that the feeding of the emulsifier (E) and the dry comminution of the wax (W) in the presence of the emulsifier (E) are preferably carried out at a temperature exceeding the melting temperature of the emulsifier (E) when the emulsifier (E) is not present in dissolved form.

[0110] Therefore, when the emulsifier is liquid at room temperature, as in the case of many nonionic surfactants, the feeding and dry pulverization can be carried out at room temperature. In the case of an emulsifier that is solid at room temperature but can be converted into a liquid aggregate state by melting, the dry pulverization of the wax (W) can preferably be carried out at a correspondingly higher temperature.

[0111] Preferably, in these cases, the melting temperature of the emulsifier (E) is at least 10° C. below the melting temperature of the wax (W). Otherwise, partial softening / melting of the wax (W) may impair the dry comminution process.

[0112] Alternatively, the emulsifier (E) may also be present in dissolved form, for example in an aqueous solution. This is particularly useful in the case of emulsifiers (E) which have a high melting point and therefore cannot be provided in liquid form without also melting the wax (W), or which undergo thermal degradation before they can be converted into a liquid aggregate state. This is the case with some ionic surfactants.

[0113] Providing the emulsifier (E) in dissolved form can likewise be advantageous, since this enables a better distribution of the emulsifier (E). At the same time, when the emulsifier (E) is provided in dissolved form, the optional density additive (D) and the optional further additive (A) can also be provided in dispersed or dissolved form in the same solution. Preferably, the emulsifier (E) is a liquid emulsifier at room temperature and / or is provided in the form of an aqueous solution.

[0114] Preferably, the emulsifier (E) is sprayed onto the wax (W) in a liquid or dissolved form when the wax (W) is pulverized.

[0115] Dry comminution can be carried out by any comminution method that allows dry comminution of wax in the presence of an emulsifier (E), preferably in liquid or dissolved form. Preferably, the micronized wax composition (C) has a volume median particle size D in the range of 3 to 30 μm, more preferably 4 to 20 μm, more preferably 5 to 15 μm, more preferably 7 to 10 μm after dry comminution. 50(Measured in water with the device Mastersizer 3000 from Malvern Panalytical). Furthermore, at least 99% by volume of the particles of the micronized wax composition (C) have a size of at most 100 μm, more preferably at most 80 μm, more preferably at most 60 μm, more preferably at most 30 μm after dry comminution.

[0116] In order to obtain such a particle size, suitable mills can be used. Such mills are, for example, impact mills, hammer mills, pin mills and jet mills.

[0117] Preferably, a mechanical impact mill or an air jet mill provided with a classifier can be used. Suitable mills and classifiers are sold, for example, by Hosokawa Alpine AG. The emulsifier (E) can be sprayed into the grinding chamber, for example, via a nozzle (in liquid or dissolved form), or pre-placed with the wax (W). Preferably, the emulsifier (E) is sprayed into the grinding chamber in liquid or dissolved form.

[0118] Preferably, the following amounts of components are used in the case of dry comminution:

[0119] a) 40 to 99.9% by weight, preferably 50 to 99% by weight, more preferably 60 to 98.8% by weight, more preferably 65 to 98.5% by weight, more preferably 70 to 98% by weight, of at least one wax (W), based on the total weight of the components used;

[0120] b) 0.1 to 20% by weight, preferably 1 to 15% by weight, more preferably 1.2 to 8% by weight, more preferably 1.5 to 5% by weight, more preferably 2 to 4% by weight, of at least one emulsifier (E), based on the total weight of the components used;

[0121] c) optionally 0 to 59.9 wt. %, preferably 0 to 45 wt. %, more preferably 0 to 38 wt. %, more preferably 0 to 30 wt. %, more preferably 0 to 26 wt. %, based on the total weight of the components used, of at least one density additive (D); and

[0122] d) optionally 0 to 50% by weight, preferably 0 to 45% by weight, more preferably 0 to 38% by weight, more preferably 0 to 30% by weight, more preferably 0 to 26% by weight, based on the total weight of the components used, of at least one further additive (A).

[0123] Preferably, the sum of a), b), c) and d) is 100% by weight, so that no further components are used.

[0124] When at least one density additive (D) is used, its amount is typically at least 0.1 wt.-%, preferably at least 1 wt.-%, more preferably at least 5 wt.-%, based on the total weight of the components used. In these cases, the upper limit of the amount of wax (W) used is adjusted accordingly so that the sum of the components does not exceed 100 wt.-%.

[0125] The density additive (D) can be co-metered into the grinding chamber by volume or weight to obtain a corresponding composition of the wax composition (C), or premixed by weight with the wax.

[0126] When at least one further additive (A) is used, its amount is typically at least 0.01% by weight, preferably at least 0.1% by weight, more preferably at least 1% by weight, based on the total weight of the components used. In these cases, the upper limit of the amount of wax (W) used is adjusted accordingly so that the sum of the components does not exceed 100% by weight.

[0127] The wax composition (C) according to the invention can be used for preparing aqueous preparations.

[0128] Surprisingly, it has been found that the wax composition (C) according to the invention can be dispersed significantly faster in water or water-based paints and inks than similar compositions in which the wax (W) is mixed with the emulsifier (E) only after micronization. Without wishing to be bound by a particular theory, it is believed that by dry comminution of the wax (W) in the presence of the emulsifier (E) the surface of the wax particles is wetted more uniformly than in the case of mixing after micronization, thus significantly simplifying and accelerating the subsequent dispersion in water and additionally allowing less emulsifier to be used in the wax composition (C) according to the invention.

[0129] The method for preparing an aqueous formulation according to the present invention comprises the following steps: i) providing water, a micronized wax composition (C) according to the present invention and optionally further components; ii) mixing the components provided in step i).

[0130] Providing the micronized wax composition (C) according to the invention in step i) can be carried out, for example, by comminuting at least one wax (W) in the presence of at least one emulsifier (E), preferably in liquid or dissolved form, and optionally in the presence of at least one density additive (D) and / or at least one further additive (A) immediately before step ii). Alternatively, storage of the micronized wax composition (C) can be carried out between dry comminution and mixing in step ii).

[0131] In the case of this process, the amounts of micronized wax composition (C), water and optional further components, and also the types of optional further components, are selected according to the desired concentration in the aqueous formulation described in more detail below.

[0132] Mixing can be done by any method. For example, mixing can be done by stirring, vibrating or even shaking the components. Other methods for mixing can also be applied, such as mixing using a static mixer, by transmitting gas or by creating turbulence through ultrasound.

[0133] Stirring can be carried out, for example, by means of a mechanical stirrer such as a KPG stirrer, a hand mixer, a rod mixer, a stand mixer, a disperser, a blade stirrer, a magnetic stirrer or manually (for example with a spatula or a spoon). Vibration and shaking can likewise be carried out manually or by automated methods, wherein shaking in this context means a milder form of vibration, wherein the formation of bubbles by mixing with the gas phase is avoided as much as possible by avoiding, for example, vertical movements of the container or the components to be mixed.

[0134] Suitable devices for shaking and / or agitation are, for example, mixers, rotators, bottle rollers, swing mixers and vibration devices.

[0135] Preferably, mixing is performed by stirring or shaking, more preferably by stirring.

[0136] The aqueous preparation according to the invention comprises water and 0.01 to 60 wt. %, preferably 0.1 to 50 wt. %, more preferably 0.2 to 4 wt. % or 30 to 40 wt. %, more preferably 0.3 to 3 wt. % or 32 to 38 wt. % of a micronized wax composition (C), based on the total weight of the aqueous preparation, wherein the micronized wax composition (C) is dispersed in water.

[0137] In addition, the aqueous preparation can also contain other components. These other components can be selected arbitrarily, and are typically selected according to the final application of the aqueous preparation. Other components can also include the individual ingredients of the micronized wax composition (C) of other amounts at this. For example, other components can include other emulsifiers (E), density additives (D) and / or other additives (A), even if these are already included in the micronized wax composition (C).

[0138] For example, the further components may comprise stabilizers such as antioxidants, UV stabilizers and heat stabilizers, plasticizers, wetting aids, defoamers, processing aids, thixotropic agents, gelling agents, thickeners, fragrances, antimicrobial agents, dyes and pigments, polymers, film formers, fillers, resins and / or hardening accelerators.

[0139] The aqueous preparation according to the invention can be an aqueous concentrate or can already be a ready-to-use aqueous product, such as a water-based paint or a water-based printing ink. Preferably, the aqueous preparation is an aqueous wax concentrate, a water-based flexographic printing ink, a water-based polyurethane paint or a water-based acrylic paint.

[0140] As a wax concentrate, the aqueous preparation typically comprises 20 to 60 wt %, preferably 25 to 50 wt %, more preferably 30 to 40 wt %, more preferably 32 to 38 wt % of the micronized wax composition (C), based on the total weight of the aqueous preparation.

[0141] Preferably, the wax concentrate further comprises at least one thickener, preferably selected from methylcellulose, xanthan gum, gelatin and agar, more preferably methylcellulose. A suitable amount of thickener is typically between 0.01 and 20 wt %, preferably between 0.05 and 10 wt %, more preferably between 0.1 and 1 wt %, based on the total weight of the aqueous preparation.

[0142] In one embodiment, the aqueous preparation is a wax concentrate comprising water and 30 to 40% by weight, preferably 32 to 38% by weight, more preferably 34 to 36% by weight of a micronized wax composition (C) and a thickener, preferably selected from methylcellulose, xanthan gum, gelatin and agar, more preferably methylcellulose, based on the total weight of the aqueous preparation. Wax concentrates for general use can, for example, consist of a micronized wax composition (C), water and a thickener, and are admixed with additional components such as fragrances, colorants, etc., just for the preparation of ready-to-use aqueous products.

[0143] As a ready-to-use aqueous product, for example as a water-based paint or a water-based printing ink, the aqueous preparation typically comprises 0.01 to 20% by weight, preferably 0.05 to 15% by weight, more preferably 0.1 to 10% by weight, more preferably 0.2 to 4% by weight, more preferably 0.3 to 3% by weight of a micronized wax composition (C), based on the total weight of the aqueous preparation. In addition, such a ready-to-use aqueous product typically comprises additional components customary for the respective type of product.

[0144] Ready-to-use aqueous products such as paints and printing inks can be prepared directly from the micronized wax composition (C) by mixing with water and further components, or from a wax concentrate by mixing with further components. Wax concentrates or micronized wax compositions (C) can likewise be incorporated directly into paints or printing inks, in order, for example, to improve the scratch resistance of the finished paint or printing ink.

[0145] The present invention is more specifically described by the following examples and claims. Example

[0146] Materials used:

[0147] W1: PE 130GR (Clariant SE): HDPE wax pellets with a particle diameter of about 7 mm, a dropping point of 127 to 132°C, an acid value of 0 mg KOH / g and a viscosity of 0.96 to 0.98 g / cm 3 density.

[0148] W2: PE 4201GR (Clariant SE): HDPE wax pellets with a particle diameter of about 5 mm, a dropping point of 125 to 130°C, an acid value of 0 mg KOH / g and a viscosity of 0.96 to 0.98 g / cm 3 density.

[0149] W3: micronized HDPE wax with a D50 value (volume median) of 7.5 to 9.5 μm, a dropping point of 127 to 132 °C, an acid value of 0 mg KOH / g, and an acid value of 0.96 to 0.98 g / cm 3 The density of W1 was prepared by dry comminution as described in Preparation Example 1 (without emulsifier and density additive).

[0150] W4: 3715 (Clariant SE): micronized oxidized HDPE wax with a D50 value of 7.5 to 9.5 μm, a dropping point of 122 to 127°C, an acid value of 2-5 mg KOH / g and an acid value of 0.96 to 0.98 g / cm 3 density.

[0151] W5: AF 30 (BASF SE): micronized HDPE wax with a D50 value of about 6.5 μm, a dropping point of 112 to 120°C, an acid value of 1 to 3.6 mg KOH / g and a viscosity of 0.94 to 0.96 g / cm 3 density.

[0152] W6: A12 (Honeywell, Inc.): micronized oxidized HDPE wax with a D50 value of 10 to 13 μm, a dropping point of about 137°C, an acid value of 26 to 40 mg KOH / g, and a viscosity of about 0.99 g / cm 3 density.

[0153] W7: 1060 Vita (Clariant SE): micronized oxidized rice bran wax with a D50 value of 11-14 μm, a dropping point of 75-80°C, an acid value of 45-55 mg KOH / g and an acid value of about 0.99 g / cm 3 density.

[0154] W8: Licocare RBW 102FL Vita (Clariant SE): oxidized rice bran wax flakes with a flake diameter of about 2-5 mm, a dropping point of 75-80° C., an acid value of 45-55 mg KOH / g and a viscosity of about 0.99 g / cm 3density.

[0155] W9: Ceridust 1041 Vita (Clariant SE): micronized oxidized rice bran wax with a D50 value of 6-9 μm, a dropping point of 75-82°C, an acid value of 15-25 mg KOH / g and a viscosity of about 0.99 g / cm 3 density.

[0156] E1: nonionic emulsifier, fatty alcohol-polyglycol ether with an HLB value of about 11.

[0157] E2: Plant-based nonionic emulsifier, palm fatty alcohol-polyglycol ether with an HLB value of about 10 to 12.

[0158] D1: barium sulfate powder, with a D50 value of about 5 μm; density 4.5 g / cm 3 .

[0159] D2: low molecular weight PTFE wax with an average particle size of 4 μm (determined according to ASTM D4894); density: about 2.2 g / cm 3 .

[0160] D3: mixture of polysaccharides; density: about 1.5 g / cm 3 .

[0161] Verify particle size distribution by means of laser diffraction (Mastersizer 3000 of Malvern Panalytical, measured in water).For this reason, take (about 150mg) sample of the material to be analyzed with a small measuring spoon and place it in a 50mL beaker.Add 0.75ml of 5% emulsifier (nonylphenol polyglycol ether with 9 ethoxy units) aqueous solution, and drip 3 drops of 2-propanol by means of a plastic pipette (3mL, 0.5mL scale).Supplement the mixture with 20mL demineralized water, and stir 3 minutes at 1000 rev / min with a blade stirrer without contacting the wall of the beaker with the stirrer.After stirring, the sample is placed in a cooling ultrasonic bath for 3 minutes, and then immediately checked by means of laser diffraction.Measure according to the operating instructions of the instrument used (Mastersizer 3000 of Malvern Panalytical).

[0162] Preparation Example 1 (according to the present invention):

[0163] The wax (W1( Dry comminution of the PE130 granules), W8 (Licocare RBW 102FL VITA)) was carried out with the aid of a Zirkoplex classifier mill ZPS200 (Hosokawa Alpine AG) with classifying wheels or with the aid of a fluidized bed reverse jet mill AFG 200 (Hosokawa Alpine AG) with integrated classifier.

[0164] Dry comminution is initially carried out without emulsifiers in order to adjust the equipment-specific parameters in order to obtain a micronized wax having a particle size distribution with D50 values ​​in the range of 5 to 15 μm, D90 values ​​in the range of 10 to 40 μm and D99 values ​​in the range of 15 to 70 μm.

[0165] The grinding material comprises the wax (W) and, if present, the density additive (D) as a solid mixture. As described above, the particle size distribution is verified by means of laser diffraction (Mastersizer 3000 from Malvern Panalytical, measured in water). After reaching a particle size distribution within the given range, the parameters remain constant.

[0166] To prepare the wax composition (C), the emulsifier is then sprayed from the side onto the grinding disc (ZPS200) or directly into the grinding chamber (AFG200) during grinding over a period of 5 to 40 minutes.

[0167] To prepare the micronized wax W3, the process is accordingly carried out without density additive (D) and without addition of emulsifier.

[0168] The conditions and results of the dry pulverization are shown in Table 1 (ZPS200) and Table 2 (AFG200).

[0169] Table 1

[0170] Composition (C) C1 C2 C3 C4 C5 C6 C7 Wax (W) W1 W1 W1 W1 W1 W1 W1 Emulsifier (E) E1 E1 E1 E1 E1 E1 E1 Share (E) [wt%]* 1.2 2.7 3.2 3.3 2.5 0.9 4.1 <![CDATA[Density [g / cm 3 > 0.97 0.97 0.97 0.976 0.97 0.97 0.97 D50[μm] 8.48 8.91 9.14 8.87 9.28 9.37 14.4 D90[μm] 17.5 17.9 18.5 17.4 18.4 18.2 35.7 D99[μm] 26.4 26.5 28.5 25.9 27.2 26.4 60.0

[0171] *Amount used is based on the weight of all ingredients used

[0172] Table 2

[0173]

[0174]

[0175] *Amount used is based on the weight of all ingredients used

[0176] Preparation Example 2 (Comparative):

[0177] Micronized wax W3 by Hausschild DAC 150 (Hausschild GmbH & Co. KG) was blended dry (at 2000 RPM) with 3% by weight (composition V1) or with 18% by weight (composition V2) of emulsifier E1.

[0178] Example 1 (Flowability / Free Flowability)

[0179] A down tube (open glass cylinder; 20 cm high, 1.5 cm diameter) was placed on a dark test pad so that the lower opening was closed by the test pad. 2.5 g of each micronized wax composition (Table 3) was filled into the down tube from above. The down tube was lifted to a distance of about 2 cm from the pad so that the wax powder could fall and produce a bulk material cone. The diameter of the resulting bulk material cone was measured with a ruler. Flatter, wider bulk material cones mean better flowability / free flowability.

[0180] Tests have shown that firstly, flowability / free-flowability is better at low emulsifier levels and secondly, dry comminution of the wax in the presence of an emulsifier results in better flowability / free-flowability than when the emulsifier is blended with the micronized wax after micronization.

[0181] Table 3

[0182] Composition V1 V2 C4 Wax (W) W3 W3 W1 D50[μm] 7.5-9.5 7.5-9.5 8.87 Emulsifier (E) E1 E1 E1 Emulsifier content [weight %] 3 18 3 Diameter of cone for loose material [mm] Approx. 45 Approx. 40 Approx. 50

[0183] Example 2 (Dispersibility)

[0184] 35 wt % of the micronized wax composition was dispersed in a mixture containing 64.7 wt % of demineralized water, 0.1 wt % of a thickener (xanthan gum), 0.1 wt % of a defoamer (Evonik Industries AG) and 0.1 wt % of a defoamer. Foamex 810) and 0.1 wt% antimicrobial agent (Proxel TM GXL) in an aqueous solution (1500RPM for 15 min) and observe the duration of dispersion stability.

[0185] Only by first pre-adding the emulsifier E1 in aqueous solution and then incorporating the micronized wax W3 can a stable dispersion with wax W3 be prepared in a conventional manner. In contrast, the micronized wax compositions C1-C12 according to the invention can be directly incorporated into aqueous solution without additional pre-addition of an emulsifier. The dispersion stability at room temperature is shown in Table 4.

[0186] Table 4 (+: stable; -: separated)

[0187]

[0188] Starting from an emulsifier dosage of 2.5% by weight, the micronized wax composition (C) according to the invention can also be dispersed in water within a short time (<2 min) by shaking, manually stirring or agitating the respective container.

[0189] Dispersions containing compositions C9 to C11 comprising density additive (D) remain stable over a longer period of time and show a different phase separation behavior after prolonged storage (the solid does not float on the aqueous solution but sinks to a greater extent below the water surface due to the increased density). This also further facilitates redispersibility in the event of phase separation after longer storage.

[0190] Example 3 (Dispersibility Compared to Polar Modified Wax)

[0191] Initially, 90 g of demineralized water was placed in a 250 mL beaker, and 10 g of micronized wax composition C4 or one of the polar waxes W4, W6 or W7 was added to the water surface. A blade stirrer was then immersed in the water until it was only a few millimeters from the bottom of the beaker.

[0192] The stirring process was started at 700 rpm and then stopped after 5 min. The blade stirrer was then moved upwards and the mixture was observed. The observation was stopped after 2 hours.

[0193] In the case of the micronized wax composition C4, wetting of the solid with water was observed already before the start of stirring. In the case of waxes W4, W6 and W7, the wax floated without visible wetting.

[0194] In the case of waxes W4, W6 and W7, immediately after the stirring process was terminated, the mixture separated completely, forming a clear aqueous phase on which the wax floated. In contrast, the micronized wax composition C4 formed a stable and homogeneous wax dispersion which showed no visible changes even after 2 hours.

[0195] Example 4 (water-based one-component polyurethane paint)

[0196] The dispersion was prepared by pre-preparing a ready-to-use water-based one-component polyurethane lacquer (e.g. Bona Mega from Bona Vertriebsgesellschaft mbH) and slowly or quickly adding the micronized wax composition or the micronized wax and dispersing it with a laboratory disperser (VMA-Getzmann GmbH). LC30) was incorporated into the paint at 500 RPM for 0.5 min and then at 1000 RPM for 1 min (total 1.5 min) to prepare an aqueous formulation.

[0197] The mixture was then mounted between two slides (glass) and the visible wax agglomerates were counted.

[0198] The results are shown in Table 5.

[0199] Table 5

[0200]

[0201] a) Quick Add

[0202] Table 6

[0203]

[0204] a) Quick Add

[0205] In the case of the comparative formulation, a homogeneous dispersion with <50 agglomerates could only be seen at significantly higher stirrer speeds and significantly longer dispersion times (20 min at 2000 RPM).

[0206] It can be clearly seen from these results that the micronized wax composition (C) according to the invention can be incorporated into water-based paints significantly faster and significantly more evenly than commercially available waxes (unmodified and modified) and compared to wax compositions (V1, V2) to which the emulsifier is added only after micronization.

[0207] Similar results were observed for one-component acrylic lacquers and printing inks for flexographic printing.

[0208] Example 5 (Scratch resistance of paint)

[0209] A one-component polyurethane lacquer was prepared as in Example 4, with dispersion at 2000 RPM for 20 min. The dispersion time of 20 min was also chosen in order to allow uniform incorporation of the comparative examples W3 and W4. In the case of shorter dispersion times, these are present in the lacquer in the form of agglomerates, so that the lacquer surface to be tested prepared therefrom is also inhomogeneous and therefore not testable. The wax composition (C) according to the invention is testable even after incorporation according to Example 4.

[0210] The formulations were applied to glass plates, hardened, and their scratch resistance was checked.

[0211] For this purpose, the hardness test needle method (DIN EN ISO 1518-1:2019) and the Schmiss test (ASTM5178-21) were carried out. The results are shown in Table 6.

[0212] Table 7

[0213] (W) / (C) W3 W4 C4 C5 C7 Paint amount [weight %] 100 98 98 98 98 98 (W) / (C) amount [weight %] 0 2 2 2 2 2 Hardness test needle [N] 0.6 0.9 0.7 1.0 1.0 1.2 Schmiss test [N] 0.7 0.9 0.4 1.2 1.4 1.6

[0214] In a similar manner, one-component acrylic lacquers with micronized wax / wax compositions were prepared and their scratch resistance was checked in accordance with DIN EN ISO 1518-1: 2019. The results are shown in Table 7.

[0215] Table 8

[0216] (W) / (C) W3 W4 C2 C3 C4 C5 C7 Paint amount [weight %] 100 98 98 98 98 98 98 98 (W) / (C) amount [weight %] 0 2 2 2 2 2 2 2 Hardness test needle [N] 0.2 1.3 1.2 1.5 1.5 1.6 1.4 1.6 Paint amount [weight %] 100 96 96 96 96 96 96 96 (W) / (C) amount [weight %] 0 4 4 4 4 4 4 4 Hardness test needle [N] 0.2 1.2 1.3 1.7 1.6 1.7 1.5 1.7

[0217] It is evident from the results that paints containing the micronized wax composition (C) according to the invention have comparable or higher scratch resistance than paints with commercially available waxes (unmodified and modified).

Claims

1. A method for preparing a micronized wax composition (C), comprising the following steps: In the presence of at least one emulsifier (E), optionally at a density of >1 g / cm at 20°C 3 Dry comminuting at least one wax (W) in the presence of at least one density additive (D) of at least one wax (W), wherein the density additive (D) is substantially insoluble in water at 20° C., and optionally in the presence of at least one further additive (A) which is different from the at least one wax (W), the at least one emulsifier (E) and the at least one density additive (D).

2. The process according to claim 1, wherein the comminution is carried out with less than 20% by weight of water, based on the amount of wax (W) used for comminution.

3. The method according to claim 1 or 2, wherein the at least one emulsifier (E) is present in liquid or dissolved form during comminution.

4. The process according to claims 1 to 3, wherein the wax (W) does not substantially form a stable dispersion in water.

5. The method according to any one of claims 1 to 4, wherein the density additive (D) comprises an organic additive, preferably selected from halogenated organic polymers and polysaccharides, more preferably selected from polytetrafluoroethylene wax, cellulose, hemicellulose; and / or an inorganic additive, preferably selected from salts, more preferably selected from salts of alkaline earth metals, more preferably selected from calcium sulfate, calcium carbonate, barium sulfate and barium carbonate.

6. The method according to any one of claims 1 to 5, wherein the following amounts of components are used during comminution: a) 40 to 99.9% by weight, preferably 50 to 99% by weight, more preferably 60 to 98.8% by weight, more preferably 65 to 98.5% by weight, more preferably 70 to 98% by weight, of the at least one wax (W), based on the weight of the components used; b) 0.1 to 20% by weight, preferably 1 to 15% by weight, more preferably 1.2 to 8% by weight, more preferably 1.5 to 5% by weight, more preferably 2 to 4% by weight, of the at least one emulsifier (E), based on the weight of the components used; c) optionally 0 to 59.9 wt. %, preferably 0 to 45 wt. %, more preferably 0 to 38 wt. %, more preferably 0 to 30 wt. %, more preferably 0 to 26 wt. % of at least one density additive (D), based on the weight of the components used; and d) optionally 0 to 50% by weight, preferably 0 to 45% by weight, more preferably 0 to 38% by weight, more preferably 0 to 30% by weight, more preferably 0 to 26% by weight, based on the weight of the components used, of the at least one further additive (A).

7. The method according to any one of claims 1 to 6, wherein the wax (W) is selected from the group consisting of synthetic organic waxes, partially synthetic organic waxes, natural waxes and mixtures thereof, wherein the wax may optionally be oxidized or otherwise chemically modified, preferably selected from polyolefin waxes, montan waxes, rice bran waxes, beeswax, sunflower wax, corn wax, carnauba wax, Fischer-Tropsch waxes, paraffin waxes, ester waxes and amide waxes, more preferably selected from polyethylene waxes, polypropylene waxes, poly(ethylene-co-propylene) waxes, rice bran waxes, corn waxes and sunflower waxes, more preferably HDPE waxes.

8. The method according to any one of claims 1 to 7, wherein the emulsifier (E) is sprayed onto the wax (W) in a liquid or dissolved form when the wax (W) is pulverized.

9. The method according to any one of claims 1 to 8, wherein the wax (W) is not oxidized and not grafted with heteroatom-containing groups and preferably contains no polar groups.

10. The process according to any one of claims 1 to 9, wherein the wax (W) contains polar groups, is preferably oxidized or grafted with heteroatom-containing groups.

11. The process according to any one of claims 1 to 10, wherein the amount of density additive (D) is selected such that the density of the micronized wax composition (C) is in the range of 0.94 to 1.20 g / cm at 20°C. 3 , preferably 0.96 to 1.10 g / cm 3 , more preferably 0.98 to 1.06 g / cm 3 , more preferably 1.00 to 1.04 g / cm 3 within the range.

12. The method according to any one of claims 1 to 11, wherein the wax (W) is comminuted to a volume median D50 of a particle size in the range of 3 to 30 μm, preferably 4 to 20 μm, more preferably 5 to 15 μm, more preferably 7 to 10 μm.

13. A micronized wax composition (C) comprising (preferably consisting of): a) at least one wax (W); b) at least one emulsifier (E); c) optionally at least one density additive (D) having a density of >1 g / cm at 20°C 3 , preferably >1.3g / cm 3 , wherein the density additive (D) is substantially insoluble in water at 20° C.; and d) optionally at least one further additive (A) which is different from the at least one wax (W), the at least one emulsifier (E) and the at least one density additive (D), The micronized wax composition (C) is obtained by the method according to any one of claims 1 to 12.

14. The micronized wax composition (C) according to claim 13, wherein the water content of the micronized wax composition (C) is less than 20% by weight, preferably less than 10% by weight, particularly preferably less than 5% by weight, based on the total weight of the micronized wax composition (C), as measured using a moisture analyzer HR73 from Mettler Toledo.

15. The micronized wax composition (C) according to claim 13 or 14, comprising: a) 40 to 99.9 wt. %, preferably 50 to 99 wt. %, more preferably 60 to 98.8 wt. %, more preferably 65 to 98.5 wt. %, more preferably 70 to 98 wt. % of the at least one wax (W), based on the weight of the micronized wax composition (C); b) 0.1 to 20 wt. %, preferably 1 to 15 wt. %, more preferably 1.2 to 8 wt. %, more preferably 1.5 to 5 wt. %, more preferably 2 to 4 wt. % of the at least one emulsifier (E), based on the weight of the micronized wax composition (C); c) optionally 0 to 59.9 wt. %, preferably 0 to 45 wt. %, more preferably 0 to 38 wt. %, more preferably 0 to 30 wt. %, more preferably 0 to 26 wt. % of said at least one density additive (D), based on the weight of the micronized wax composition (C); and d) optionally 0 to 50 wt. %, preferably 0 to 45 wt. %, more preferably 0 to 38 wt. %, more preferably 0 to 30 wt. %, more preferably 0 to 26 wt. % of the at least one further additive (A), based on the weight of the micronized wax composition (C).

16. An aqueous formulation comprising water and 0.01 to 60 wt. %, preferably 0.1 to 50 wt. %, more preferably 0.2 to 4 wt. % or 30 to 40 wt. %, more preferably 0.3 to 3 wt. % or 32 to 38 wt. % of the micronized wax composition (C) according to any one of claims 13 to 15, based on the total weight of the aqueous formulation, wherein the micronized wax composition (C) is dispersed in water.

17. The aqueous formulation according to claim 16, wherein the aqueous formulation is a wax concentrate comprising water and 30 to 40 wt. %, preferably 32 to 38 wt. %, more preferably 34 to 36 wt. % of micronized wax (C), based on the total weight of the aqueous formulation, and a thickener, preferably selected from methylcellulose, xanthan gum, gelatin and agar, more preferably methylcellulose.

18. The aqueous formulation according to claim 16, wherein the aqueous formulation is a water-based printing ink or a water-based paint, preferably a water-based flexographic printing ink, a water-based polyurethane paint or a water-based acrylic paint.

19. A method for preparing a water-based formulation comprising the steps of: i) providing water, a micronized wax composition (C) according to any one of claims 13 to 15 and optionally further components; ii) mixing the components provided in step i), preferably by stirring, vibrating or shaking.

20. The process according to claim 19, wherein the micronized wax composition (C) is provided in step i) by being carried out in the presence of at least one emulsifier (E), preferably in liquid or dissolved form, and optionally in the presence of at least one density additive (D) and / or at least one further additive (A), immediately before step ii), or comprises storage between comminution and mixing in step ii).

21. Use of the micronized wax composition (C) according to any one of claims 13 to 15 for preparing an aqueous formulation.

22. Use of the micronized wax composition (C) according to any one of claims 13 to 15 and / or a wax concentrate obtained therefrom for improving the scratch resistance of coatings produced from aqueous formulations.

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