Powder coating comprising redispersible dispersion powder

Abstract

The present invention relates to specific pyrrolidone-based (co) polymers as spray drying additives (also referred to as spray drying aids; sDA) for use in powder coatings comprising at least one redispersible dispersion powder (RDP). The invention also relates to a powder coating comprising an RDP comprising at least one (co) polymer selected from the group consisting of acrylate polymers and acrylic-styrene copolymers and at least one pyrrolidone-based (co) polymer, and to a method for producing a coating.

Description

[0001] The present invention relates to the use of specific pyrrolidone-based (co)polymers as spray drying additives (also called spray drying aids; SDA) in powder coatings comprising at least one redispersible dispersion powder (RDP). The present invention also relates to a powder coating comprising an RDP comprising at least one (co)polymer selected from the group consisting of acrylate polymers and acrylic-styrene copolymers and at least one pyrrolidone-based (co)polymer and a method for producing a coating.

[0002] Powder coatings have the advantage of reducing CO2 emissions from transportation due to the reduced overall weight. In addition, powder coatings provide long-term stability because they do not contain a liquid medium.

[0003] A suitable method for converting an aqueous dispersion into a redispersible dispersion powder (RDP) is spray drying. This involves spraying and dehydrating the aqueous dispersion in a stream of hot air. In order to ensure spray drying of the dispersion and redispersibility of the dispersion powder, a spray drying additive (SDA) is usually added to the aqueous dispersion. During the spray drying process, it is assumed that the SDA forms a protective shell around the dispersion particles, thereby preventing the particles from filming during the spray drying process.

[0004] Formaldehyde condensation products can be used as SDAs, such as melamine-formaldehyde (DE 2049114 A1), phenolsulfonic acid-formaldehyde (WO 98 / 03576 A1) and naphthalenesulfonic acid-formaldehyde condensation products (WO 98 / 03577 A1). However, these SDAs described in the prior art have disadvantages. For example, they discolor the dispersion powders, they show a coloring effect under UV light (yellow-brown discoloration), and formaldehyde is emitted during production and / or in the application system.

[0005] Therefore, there is a continuing need to provide suitable spray drying aids for the production of powder coatings and powder coatings comprising these spray drying aids.

[0006] Against this background, it is an object of the present invention to provide a suitable spray drying aid for the manufacture of powder coatings. In this context, it is an object of the present invention to provide an SDA with less discoloration. Furthermore, it is an object of the present invention to provide an SDA with reduced formaldehyde emissions during manufacture and / or in an application system (e.g. in powder coatings). Furthermore, it is an object of the present invention to provide an environmentally friendly SDA. Another object of the present invention is to provide a redispersible dispersion powder with suitable redispersibility. An additional object of the present invention is to provide a stable powder coating. In this context, it is an object of the present invention to provide a powder coating with reduced discoloration and / or reduced formaldehyde emissions. Furthermore, it is an object of the present invention to provide a durable coating.

[0007] It has surprisingly been found that at least one of these objects can be achieved by using a pyrrolidone-based (co)polymer as SDA in a powder coating comprising at least one redispersible dispersion powder (RDP) as claimed. It has also been found that the powder coating as defined below provides improved wet scrub resistance as well as suitable redispersibility.

[0008] In a first aspect, the present invention therefore relates to a pyrrolidone-based (co)polymer for use or the use of a pyrrolidone-based (co)polymer as a spray drying aid in a process for producing a powder coating comprising at least one redispersible dispersion powder (RDP) comprising

[0009] i) a (co)polymer selected from the group consisting of acrylate polymers, acrylic acid-styrene copolymers, styrene-butadiene based copolymers and mixtures thereof,

[0010] and

[0011] ii) The pyrrolidone-based (co)polymers.

[0012] In the following, preferred embodiments of the components of the RDP are described in more detail. It should be understood that each preferred embodiment is relevant both by itself and in combination with other preferred embodiments.

[0013] In a preferred embodiment A1 of the first aspect, the pyrrolidone-based (co)polymer is homopolymeric N-vinylpyrrolidone or a copolymer of N-vinylpyrrolidone and vinyl acetate.

[0014] In a preferred embodiment A2 of the first aspect, the at least one pyrrolidone-based (co)polymer is a pyrrolidone-containing polymer (PP) comprising at least one unit of the general formula (I) to (III):

[0015]

[0016]

[0017] wherein R is independently hydrogen, C1-C4-alkyl, or two groups R are linked to each other to form a six-membered ring;

[0018] X is -O- or -NR;

[0019] A is independently selected from C1-C 20 -alkanediyl, C3-C 20 -cycloalkanediyl and C6-C 20 - a group consisting of an arylene group,

[0020] Among them, C1-C20 -alkanediyl is optionally interrupted by one or more non-adjacent oxygen atoms, sulfur atoms or functional groups -NR-, -CO-, -CO-O-, -CO-NR-, -SO- or -SO2-, in which the nitrogen atom is optionally protonated or quaternized,

[0021] Among them, C1-C 20 -alkanediyl and C3-C 20 -cycloalkanediyl optionally carries at least one selected from C(=O)R 2 and SO3H, where

[0022] R 2 Selected from Cl, Br and OR 3 The group consisting of

[0023] R 3 Choose from H, C1-C 10 Alkyl, C3-C 10 Cycloalkyl and C2-C 15 The group consisting of alkenyl groups,

[0024] Among them, C6-C 20 -arylene is optionally inserted with oxygen, sulfur, -NR-, -SO- or -SO2- and is optionally substituted with -COOH or -SO3H or a mixture of these groups;

[0025] Z is a group of formula (IV)

[0026]

[0027] Where B is C1-C 20 -alkanediyl, C6-C 20 -cycloalkanediyl or a mixture of such radicals, C1-C 20 -alkanediyl optionally interrupted by one or more non-adjacent oxygen atoms, sulfur atoms or functional groups -NR-, -CO-, -CO-O-, -CO-NR-, -SO- or -SO2-, and optionally carrying an additional functional group -COOH or -SO3H, in which the nitrogen atom in the functional group -NR- is optionally protonated or quaternized

[0028] Alternatively, Z is a mixture of a group of formula (IV) and a group A.

[0029] In a second aspect, the present invention relates to a powder coating comprising

[0030] a) 5 to 30% by weight of at least one pigment;

[0031] b) 10 to 25 wt. % of at least one redispersible dispersion powder (RDP) comprising

[0032] i) at least one (co)polymer selected from the group consisting of acrylate polymers and acrylic-styrene copolymers, and

[0033] ii) at least one pyrrolidone-based (co)polymer;

[0034] c) 40% to 78% by weight of at least one filler;

[0035] d) 0 to 2 wt. % of at least one dispersant;

[0036] d) 0% to 2% by weight of at least one thickener; and

[0037] e) 0% to 2% by weight of at least one defoamer,

[0038] each based on the total dry weight of the powder coating, wherein the pyrrolidone-based (co)polymer is a pyrrolidone-containing polymer (PP) comprising at least one unit of the general formula (I) to (III)

[0039]

[0040] wherein R is independently hydrogen, C1-C4-alkyl, or two groups R are linked to each other to form a six-membered ring;

[0041] X is -O- or -NR;

[0042] A is independently selected from C1-C 20 -alkanediyl, C3-C 20 -cycloalkanediyl and C6-C 20 - a group consisting of an arylene group,

[0043] Among them, C1-C 20 -alkanediyl is optionally interrupted by one or more non-adjacent oxygen atoms, sulfur atoms or functional groups -NR-, -CO-, -CO-O-, -CO-NR-, -SO- or -SO2-, in which the nitrogen atom is optionally protonated or quaternized,

[0044] Among them, C1-C 20 -alkanediyl and C3-C 20 -cycloalkanediyl optionally carries at least one selected from C(=O)R 2 and SO3H, where

[0045] R 2 Selected from Cl, Br and OR 3 The group consisting of

[0046] R 3 Choose from H, C1-C 10 Alkyl, C3-C 10 Cycloalkyl and C2-C 15 The group consisting of alkenyl groups,

[0047] Among them, C6-C 20 -arylene is optionally inserted with oxygen, sulfur, -NR-, -SO- or -SO2- and is optionally substituted with -COOH or -SO3H or a mixture of these groups;

[0048] Z is a group of formula (IV)

[0049]

[0050] Where B is C1-C 20 -alkanediyl, C6-C 20 -cycloalkanediyl or a mixture of such radicals, C1-C 20 -alkanediyl optionally interrupted by one or more non-adjacent oxygen atoms, sulfur atoms or functional groups -NR-, -CO-, -CO-O-, -CO-NR-, -SO- or -SO2-, and optionally carrying an additional functional group -COOH or -SO3H, in which the nitrogen atom in the functional group -NR- is optionally protonated or quaternized

[0051] Alternatively, Z is a mixture of a group of formula (IV) and a group A.

[0052] In a third aspect, the invention relates to a method for making a coating, the method comprising mixing a powder coating according to the second aspect with water, preferably wherein the solids content is adjusted to 45 to 70 wt. %, more preferably 50 to 65 wt. %, based on the total weight of the coating. DETAILED DESCRIPTION

[0053] Before describing exemplary embodiments of the present invention in detail, definitions important for understanding the present invention are given.

[0054] As used in this specification and the appended claims, the singular form "one / kind" also includes the respective plural forms, unless the context clearly indicates otherwise. In the context of the present invention, the terms "about" and "approximately" represent the precision range that those skilled in the art will understand to still ensure the technical effect of the discussed feature. The term usually indicates that the deviation from the indicated numerical value is ±10%, preferably ±5%, more preferably ±2%, and especially ±1%. It should be understood that the term "comprising" is not restrictive. For the purposes of the present invention, the term "consisting of..." is considered to be a preferred embodiment of the term "comprising". If a group is defined as comprising at least a certain number of embodiments hereinafter, this means that a group preferably consisting only of these embodiments is also covered. In addition, the terms "first", "second", "third" or "(a)", "(b)", "(c)", "(d)" and the like in the specification and claims are used to distinguish between similar elements, and are not necessarily used to describe sequential or chronological order. It should be understood that the terms used in this way are interchangeable where appropriate, and the embodiments of the present invention described herein can be operated in other sequences different from those described or shown herein. Where the terms "first", "second", "third" or "(a)", "(b)", "(c)", "(d)", "i", "ii", etc. refer to steps of a method or use or an assay, there is no continuity of time or time interval between the steps, i.e., the steps may be performed simultaneously, or there may be time intervals of seconds, minutes, hours, days, weeks, months or even years between the steps, unless otherwise stated in the application presented above or below. It should be understood that the present invention is not limited to the specific methods, protocols, reagents, etc. described herein, as these may vary. It should also be understood that the terminology used herein is for the purpose of describing specific embodiments only and is not intended to limit the scope of the present invention, which is limited only by the appended claims. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art.

[0055] As used herein, the term "substituted" means that a hydrogen atom bonded to a designated atom is replaced with a designated substituent, provided that the substitution results in a stable or chemically feasible compound. Unless otherwise specified, the substituted atom may have one or more substituents and each substituent is independently selected.

[0056] When the term "unsubstituted" or "substituted" is not explicitly mentioned in reference to a moiety, the moiety is deemed to be unsubstituted.

[0057] As used herein, the term "alkyl" represents in each case a straight-chain or branched alkyl group generally having 1 to 10 carbon atoms, preferably 1 to 5 or 1 to 4 carbon atoms or 1 to 3 or 1 or 2 carbon atoms. Examples of alkyl groups are methyl, ethyl, n-propyl, isopropyl, n-butyl, 2-butyl, isobutyl, tert-butyl, n-pentyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 2,2-dimethylpropyl, 1-ethylpropyl, n-hexyl, 1,1-dimethylpropyl, 1,2-dimethylpropyl, 1-methylpentyl, 2-methylpentyl, 3-methylpentyl, 4-methylpentyl, 1,1-dimethylbutyl, 1,2-dimethylbutyl, 1,3-dimethylbutyl, 2,2-dimethylbutyl, 2,3-dimethylbutyl, 3,3-dimethylbutyl, 1-ethylbutyl, 2-ethylbutyl, 1,1,2-trimethylpropyl, 1,2,2-trimethylpropyl, 1-ethyl-1-methylpropyl and 1-ethyl-2-methylpropyl.

[0058] The term "alkanediyl" as used herein represents a hydrocarbon having, for example, 2 to 20 carbon atoms and two free valences in each case. It is therefore a diradical having, for example, 2 to 20 carbon atoms. The term "alkanediyl" encompasses straight and branched chains, as well as saturated and unsaturated hydrocarbons having, for example, 2 to 20 carbon atoms and two free valences. Saturated hydrocarbons are preferred. Examples of C2-C20-alkanediyls are ethylene (second-1,2-diyl, dimethylene), third-1,3-diyl (trimethylene), propylene (third-1,2-diyl) and fourth-1,4-diyl (tetramethylene). The alkanediyl group is bridged to the rest of the molecule by a certain group.

[0059] The term "cycloalkanediyl" as used herein represents in each case a cyclic hydrocarbon having, for example, 3 to 20 carbon atoms and two free valences. It is therefore a diradical having, for example, 3 to 20 carbon atoms. The term "cycloalkanediyl" encompasses cyclic hydrocarbons and hydrocarbons having a cyclic fraction and a straight-chain fraction having, for example, 3 to 20 carbon atoms and two free valences. Examples of C3-C20-cycloalkanediyl are cyclopropanediyl, cyclobutanediyl, cyclopentanediyl, cyclohexanediyl, cycloheptanediyl, cyclooctanediyl and cyclodecanediyl.

[0060] The term "arylene" as used herein represents in each case a linking aromatic cyclic moiety which generally has 6 to 20 carbon atoms, for example 6, 7, 8, 10 or 12 carbon atoms. The arylene group bridges a group to the rest of the molecule. The arylene group can be, for example, a phenylene group. In this connection, it is understood that aromatic means that the Hückel (4n+2) rule is satisfied.

[0061] The term "cycloalkyl" as used herein represents in each case a cyclic hydrocarbon radical having, for example, 3 to 10 carbon atoms. The term "cycloalkyl" also encompasses hydrocarbons having a cyclic fraction and a linear fraction having, for example, 3 to 10 carbon atoms and one free valency. Examples of such cycloalkyl groups include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl and cyclodecyl.

[0062] The term "alkenyl" as used herein represents in each case an unsaturated hydrocarbon group generally having 2 to 15, preferably 2 to 10 carbon atoms, containing at least one carbon-carbon double bond in any position, for example vinyl (vinyl), allyl (2-propene-1-yl), 1-propene-1-yl, 2-propene-yl, methallyl (2-methylprop-2-ene-1-yl), 2-butene-1-yl, 3-butene-1-yl, 2-pentene-1-yl, 3-pentene-1-yl, 4-pentene-1-yl, 1-methylbut-2-ene-1-yl, 2-ethylprop-2-ene-1-yl, pentenyl, hexenyl, etc. If geometric isomers about the double bond are possible, the present invention relates to both E-isomers and Z-isomers. Preferred alkenyl groups according to the present invention are terminal alkenyl groups. The bonding of vinyl is exemplified as follows:

[0063]

[0064] The organic moieties mentioned in the above definitions of the variables are collective names for the individual lists of the individual group members. n -C m The possible number of carbon atoms in the group is indicated in each case.

[0065] In the context of the present invention, "at least one itaconic acid derivative" means exactly one itaconic acid derivative and also mixtures of two or more itaconic acid derivatives. The same applies to terms such as "at least one diamine", "at least one amino acid", "at least one (inorganic / organic) pigment", "at least one redispersible dispersion powder", "at least one (co)polymer", "at least one pyrrolidone-based (co)polymer", "at least one filler", "at least one dispersant", "at least one thickener", "at least one defoamer", etc.

[0066] The terms "component (A)" and "at least one itaconic acid derivative" are used synonymously in the context of the present invention and thus have the same meaning.

[0067] The same applies to the terms "component (B)" and "at least one amino acid". These terms are also used synonymously in the context of the present invention and therefore have the same meaning.

[0068] When referring to weight percentages of compositions and ingredients contained therein, it is to be understood that the total amount of ingredients according to the present invention does not exceed 100% (± 1% due to rounding).

[0069] As used herein, the term "particle" or "polymer particle" refers to a polymer fragment having a specific particle size Dx for a specific particle size distribution, wherein x% of the particles have a diameter less than the Dx value. 50 The particle size is the median of the particle size distribution. The particle size distribution can be determined, for example, via dynamic light scattering (e.g. according to ISO 22412:2008). The particle size distribution can be expressed as a volume distribution, a surface distribution or a number distribution. Preferably, the Dx value is a number distribution in which x% of the total number of particles have a smaller diameter.

[0070] Preferred embodiments of the use of SDA, powder coatings, and methods of making coatings are described below. It should be understood that the preferred embodiments of the invention disclosed herein are intended to be covered individually and in combination with each other. Therefore, all possible combinations of preferred embodiments also form part of the present invention.

[0071] As indicated above, the present invention relates in one embodiment to a pyrrolidone-based (co)polymer used as a spray drying aid or the use of a pyrrolidone-based (co)polymer as a spray drying aid in a process for producing a powder coating comprising at least one redispersible dispersion powder (RDP), the redispersible dispersion powder comprising

[0072] i) a (co)polymer selected from the group consisting of acrylate polymers, acrylic acid-styrene copolymers, styrene-butadiene based copolymers and mixtures thereof,

[0073] and

[0074] ii) The pyrrolidone-based (co)polymers.

[0075] In the following, preferred embodiments of use relevant to all aspects of the invention are described in more detail. It should be understood that each preferred embodiment is encompassed both individually and in combination with other preferred embodiments.

[0076] In a preferred embodiment, the pyrrolidone-based (co)polymer is a homopolymeric N-vinylpyrrolidone or a copolymer of N-vinylpyrrolidone and vinyl acetate.

[0077] The homopolymeric N-vinylpyrrolidone and the copolymer of N-vinylpyrrolidone and vinyl acetate may suitably have a weight average molecular weight (Mw; determined by gel permeation chromatography (GPC) using a 0.05 M aqueous ammonium formate / methanol mixture = 80:20 (volume parts) as eluent) of 5 kDa to 2000 kDa, preferably 6 kDa to 1500 kDa. Further suitable ranges of weight-average molecular weight (Mw; determined as given above) of the homopolymeric N-vinylpyrrolidone and the copolymer of N-vinylpyrrolidone and vinyl acetate are from 6 kDa to 12 kDa or from 20 kDa to 120 kDa or from 1000 kDa to 2000 kDa, preferably from 7 kDa to 11 kDa or from 30 kDa to 100 kDa or from 1100 kDa to 1800 kDa, and in particular from 8 kDa to 10 kDa or from 40 kDa to 70 kDa or from 1300 kDa to 1600 kDa.

[0078] The homopolymeric N-vinylpyrrolidone and the copolymer of N-vinylpyrrolidone and vinyl acetate may have a number average molecular weight (Mn; determined by gel permeation chromatography (GPC) as given above for Mw) of 0.5 kDa to 500 kDa, preferably 1 kDa to 350 kDa. Further suitable number average molecular weight ranges for the homopolymeric N-vinylpyrrolidone and the copolymer of N-vinylpyrrolidone and vinyl acetate are 0.5 kDa to 5 kDa or 9 kDa to 20 kDa or 280 kDa to 400 kDa, preferably 1 kDa to 4 kDa or 10 kDa to 18 kDa or 290 kDa to 280 kDa, and in particular 1 kDa to 3 kDa or 12 kDa to 16 kDa or 310 kDa to 340 kDa.

[0079] In this connection, the determination of the molecular weights (weight average molecular weight (Mw) and number average molecular weight (Mn)) of the polymers is generally carried out as outlined in more detail in the experimental part.

[0080] Commercially available homopolymeric N-vinyl pyrrolidones suitable for use in accordance with the present invention include, but are not limited to, K 17, K 30, K 90 and PVP10.

[0081] Suitable commercially available copolymers of N-vinyl pyrrolidone and vinyl acetate include, but are not limited to, VA 64.

[0082] In a preferred embodiment, the at least one pyrrolidone-based (co)polymer is a pyrrolidone-containing polymer (PP).

[0083] "Pyrrolidone-containing polymer (PP)" as used in the context of the present invention means that the polymer contains pyrrolidone groups, typically as part of the polymer backbone. Pyrrolidone groups are known to those skilled in the art. Pyrrolidone groups are groups having at least one carbon group derived from pyrrolidone, i.e. derived from pyrrolidone by removing one hydrogen atom from a ring atom. Divalent groups are explicitly covered by the term. The polymer may be a pyrrolidone-containing copolymer. In various embodiments, the term as used herein therefore excludes polymers in which pyrrolidone groups are side groups, such as PVP. In various embodiments, the polymer of the present invention is therefore not PVP. Pyrrolidone groups as part of the backbone may mean that they are divalent repeating units of the polymer backbone structure.

[0084] The pyrrolidone-containing polymers (PP) of the present invention are superior to known PVP polymers because they are more biodegradable and can be produced from renewable raw materials such as itaconic acid and amino acids, especially lysine. In addition, they are readily soluble in water and aqueous solutions with high polymer concentrations are readily available. Another advantage is that the polymers of the present invention can be synthesized as a melt or solid and do not have to be reacted in solution. It has further been found that the claimed pyrrolidone-containing polymers (PP) are less viscous, less hygroscopic and more stable on storage than conventional PVP polymers.

[0085] As used herein, "spray drying aids" refer to compounds that protect another compound or composition of spray drying from adverse effects that may occur when drying and being exposed to high temperatures and high pressures typical for commercial spray drying processes. Such adverse effects include, but are not limited to, irreversible aggregation and / or film formation of the spray-dried compound or composition, which may damage its subsequent use and / or application, such as redispersion in a liquid medium. Spray drying aids achieve this by forming a protective shell or matrix that coats or embeds the spray-dried compound / composition during the spray drying process. Therefore, spray drying aids are functionally different from compounds used to dissolve or serve as protective colloids, because the latter are used to improve solubility or dispersibility in liquids (usually aqueous media), while the former need to withstand conditions during spray drying and be able to protect other compounds from the adverse effects of spray drying, such as by forming a protective shell around them or forming a protective matrix in which they are embedded. It is important to note that spray drying aids therefore work in a different manner from solubilizers or protective colloids, which are generally not suitable for preventing the formation of irreversible, insoluble and / or non-dispersible aggregates when drying. In order to avoid incorporation of polymers used as spray-drying aids into the polymer of the aqueous polymer dispersion to be spray-dried, which could impair their functionality, they are generally not present during the formation of the polymer to be spray-dried, but are added to the product polymer or to a composition containing the product polymer (such as the aqueous polymer dispersion referred to herein).

[0086] In a preferred embodiment, the at least one pyrrolidone-based (co)polymer is a pyrrolidone-containing polymer (PP) comprising at least one unit of the general formula (I) to (III):

[0087]

[0088] wherein R is independently hydrogen, C1-C4-alkyl, or two groups R are linked to each other to form a six-membered ring;

[0089] X is -O- or -NR;

[0090] A is independently selected from C1-C 20 -alkanediyl, C3-C 20 -cycloalkanediyl and C6-C 20 - a group consisting of an arylene group,

[0091] Among them, C1-C 20 -alkanediyl is optionally interrupted by one or more non-adjacent oxygen atoms, sulfur atoms or functional groups -NR-, -CO-, -CO-O-, -CO-NR-, -SO- or -SO2-, in which the nitrogen atom is optionally protonated or quaternized,

[0092] Among them, C1-C 20 -alkanediyl and C3-C 20 -cycloalkanediyl optionally carries at least one selected from C(=O)R 2 and SO3H, where

[0093] R 2 Selected from Cl, Br and OR 3 The group consisting of

[0094] R 3 Choose from H, C1-C 10 Alkyl, C3-C 10 Cycloalkyl and C2-C 15 The group consisting of alkenyl groups,

[0095] Among them, C6-C 20 -arylene is optionally inserted with oxygen, sulfur, -NR-, -SO- or -SO2- and is optionally substituted with -COOH or -SO3H or a mixture of these groups;

[0096] Z is a group of formula (IV)

[0097]

[0098] Where B is C1-C 20 -alkanediyl, C6-C 20 -cycloalkanediyl or a mixture of such radicals, C1-C 20 -alkanediyl optionally interrupted by one or more non-adjacent oxygen atoms, sulfur atoms or functional groups -NR-, -CO-, -CO-O-, -CO-NR-, -SO- or -SO2-, and optionally carrying an additional functional group -COOH or -SO3H, in which the nitrogen atom in the functional group -NR- is optionally protonated or quaternized

[0099] Alternatively, Z is a mixture of a group of formula (IV) and a group A.

[0100] In a preferred embodiment, the pyrrolidone-containing polymer (PP) comprises at least one unit of the general formula (I) to (II)

[0101]

[0102]

[0103] wherein R is independently hydrogen or C1-C2-alkyl;

[0104] X is -NR;

[0105] A is independently selected from C1-C 20-alkanediyl group, the C1-C 20 -alkanediyl optionally carries at least one selected from C(=O)R 2 and SO3H, where

[0106] R 2 Selected from Cl, Br and OR 3 The group consisting of

[0107] R 3 Choose from H, C1-C 10 -alkyl, C3-C 10 -cycloalkyl and C2-C 15 A group consisting of alkenyl groups;

[0108] Z is a group of formula (IV)

[0109]

[0110] Where B is C1-C 20 -alkylene, which optionally carries an additional functional group -COOH or -SO3H, or Z is a mixture of a radical of the formula (IV) and a radical A.

[0111] Preferably, A is C1-C 20 -alkanediyl, more preferably C1-C 15 -alkanediyl, and especially C 1-10 -alkanediyl. In some embodiments, A is C1-alkanediyl, C2-alkanediyl, C3-alkanediyl, C4-alkanediyl, C5-alkanediyl or C6-alkanediyl, preferably C5-alkanediyl. The alkanediyl may preferably be linear and saturated. In various embodiments, it preferably carries a functional group C(=O)R 2 , optionally on a terminal carbon atom, such as a C1 carbon atom. In such embodiments, R 2 The group is preferably OR 3 , R 3 Preferably H.

[0112] Preferably, B is C1-C 15 -alkanediyl, more preferably C1-C 10 -alkanediyl, and especially C 1-8 -alkanediyl. In some embodiments, B is C1-alkanediyl, C2-alkanediyl, C3-alkanediyl, C4-alkanediyl, C5-alkanediyl or C6-alkanediyl, preferably C5-alkanediyl. The alkanediyl may preferably be straight chain and saturated. In various embodiments, it preferably carries a functional group -COOH, optionally on a terminal carbon atom, such as a C1 carbon atom.

[0113] In various embodiments, the pyrrolidone-containing polymer (PP) is obtainable by polymerization of a reaction mixture (rM1), wherein the reaction mixture (rM1) comprises at least the following components:

[0114] (A) at least one itaconic acid derivative, preferably wherein component (A) is selected from the group consisting of itaconic acid, itaconic anhydride, itaconic esters and itaconic acid halides, and

[0115] (B) at least one diamine, preferably wherein the diamine is selected from the group consisting of ethylenediamine,

[0116] 1,3-diaminopropane, 1,4-diaminobutane, 1,5-pentanediamine, 1,6-diaminohexane,

[0117] 1,7-diaminoheptane, 1,8-diaminooctane and 1,9-diaminononane, more preferably, is selected from ethylenediamine and 1,5-pentanediamine.

[0118] In a preferred embodiment, the reaction mixture (rM1) comprises at least two diamines, preferably selected from the group consisting of ethylenediamine, 1,3-diaminopropane, 1,4-diaminobutane, 1,5-pentanediamine, 1,6-diaminohexane and 1,7-diaminoheptane, and in particular wherein the reaction mixture (rM1) comprises ethylenediamine and 1,5-pentanediamine.

[0119] Preferably, the reaction mixture (rM1) comprises component (A) and at least one diamine, preferably the sum of at least two diamines, in a molar ratio of 10:1 to 1:10, preferably 5:1 to 1:5, in particular 4:1 to 1:2 or 3:1 to 1:5.

[0120] In a preferred embodiment, component (A) and at least one diamine, preferably the sum of at least two diamines, are present in the reaction mixture (rM1) in a molar ratio of 3:1 to 1:3, preferably 2:1 to 1:2, in particular 1.5:1 to 1:1.5.

[0121] In a preferred embodiment, the reaction mixture (rM1) comprises component (A) in a range of 35% to 99% by weight, preferably 40% to 90% by weight, more preferably 50% to 75% by weight, based on the sum of the weight percentages of component (A) and the at least one diamine, preferably based on the total weight of the reaction mixture (rM1), and the at least one diamine in a range of 1% to 65% by weight, preferably 10% to 60% by weight, more preferably 25% to 50% by weight.

[0122] Unless otherwise stated, all weight percentages of component (A) and the at least one amine and optionally contained solvent (S) such as water are based on the total weight of the composition of the reaction mixture (rM1) before the start of polymerization of the reaction mixture (rM1).

[0123] In various embodiments, the pyrrolidone-containing polymer (PP) preferably has a weight average molecular weight (Mw; determined by gel permeation chromatography (GPC) using a 0.05 M aqueous ammonium formate / methanol mixture = 80:20 (volume parts) as eluent) of 500 g / mol to 100,000 g / mol, more preferably 1,000 g / mol to 10,000 g / mol, still more preferably 2,000 g / mol to 8,000 g / mol, and especially 3,000 g / mol to 6,000 g / mol. Preferably, the pyrrolidone-containing polymer (PP) has a number average molecular weight (Mn; determined by gel permeation chromatography (GPC) with a 0.05 M aqueous ammonium formate / methanol mixture = 80:20 (volume parts) as eluent) of 500 g / mol to 20,000 g / mol, more preferably 800 g / mol to 10,000 g / mol, still more preferably 1,000 g / mol to 8,000 g / mol and in particular 1,000 g / mol to 4,000 g / mol. Preferably, the pyrrolidone-containing polymer (PP) has a K value (determined according to H. Fikentscher, Cellulose-Chemie 13, pages 48-64 and 71-94 (1932)) of 5 to 35, more preferably 10 to 30, still more preferably 14 to 25 and in particular 15 to 22.

[0124] In a preferred embodiment, the reaction mixture (rM1) comprises water. The water comprising the reaction mixture (rM1) is stirred and heated under reflux, preferably for 0.2 to 5 hours, more preferably for 0.5 to 3 hours, and especially for 0.5 to 2 hours. After heating, water is preferably removed via distillation / evaporation. The distillation can be carried out under normal pressure and / or by applying a vacuum.

[0125] In a preferred embodiment, the pyrrolidone-containing polymer (PP) is obtainable by polymerization of a reaction mixture (rM2), wherein the reaction mixture (rM2) comprises at least the following components:

[0126] (A) at least one itaconic acid derivative, preferably wherein component (A) is selected from the group consisting of itaconic acid, itaconic anhydride, itaconic esters and itaconic acid halides, and

[0127] (B) at least one amino acid of the general formula (1)

[0128] H2N–R1 –C(=O)–R 2 (1)

[0129] in

[0130] R 1 Selected from at least monosubstituted C2-C 20 -alkanediyl and at least monosubstituted C3-C 20 - the group consisting of cycloalkanediyl, wherein the substituent is NH2;

[0131] R 2 Selected from Cl, Br and OR 3 The group consisting of

[0132] R 3 Choose from H, C1-C 10 Alkyl, C3-C 10 Cycloalkyl and C2-C 15 A group consisting of alkenyl.

[0133] Preferably,

[0134] R 1 Selected from at least monosubstituted C2-C 20 -alkanediyl group, wherein the substituent is NH2, R 2 Selected from the group consisting of OH and Cl.

[0135] Particularly preferably,

[0136] R 1 Selected from precisely monosubstituted C3-C 10 -alkanediyl, wherein the substituent is NH2, such as linear and saturated C4-alkanediyl, C5-alkanediyl or C6-alkanediyl, preferably C5-alkanediyl,

[0137] R 2 It's OH.

[0138] In a preferred embodiment, component (B) is selected from the group consisting of L-lysine, D-lysine and a racemic mixture of L-lysine and D-lysine. It is particularly preferred that component (B) is L-lysine.

[0139] In a preferred embodiment, the reaction mixture (rM2) comprises component (A) in a range of 0.5% to 70% by weight, preferably 5% to 70% by weight, more preferably 10% to 60% by weight and especially 20% to 50% by weight, based on the sum of the weight percentages of component (A) and the at least one component (B), preferably based on the total weight of the reaction mixture (rM2), and at least one component (B) in a range of 30% to 99.5% by weight, preferably 30% to 95% by weight, more preferably 40% to 90% by weight and especially 50% to 80% by weight.

[0140] In a preferred embodiment, the at least one itaconic acid derivative and the at least one amino acid of general formula (1) are present in the reaction mixture (rM2) in a molar ratio of 10:1 to 1:10, preferably 6:1 to 1:5 or 5:1 to 1:5, and in particular 4:1 to 1:2 or 3:1 to 1:5 or 3:1 to 1:2.

[0141] Pyrrolidone-containing polymers (PP) are preferred, wherein the molar ratio of component (A) to component (B) in the reaction mixture (rM2) is in the range from 3:1 to 1:2 or from 3:1 to 1:10.

[0142] In this connection, the pyrrolidone-containing polymer (PP) preferably has a weight-average molecular weight (Mw; determined by gel permeation chromatography (GPC) with a 0.05 M aqueous ammonium formate / methanol mixture = 80:20 (volume parts) as eluent) of 500 g / mol to 100,000 g / mol, more preferably 1,000 g / mol to 5,0000 g / mol, still more preferably 1,000 g / mol to 10,000 g / mol and in particular 1,500 g / mol to 8,000 g / mol. Preferably, the pyrrolidone-containing polymer (PP) has a number average molecular weight (Mn; determined by gel permeation chromatography (GPC) with a 0.05 M aqueous ammonium formate / methanol mixture = 80:20 (volume parts) as eluent) of 500 g / mol to 20,000 g / mol, more preferably 500 g / mol to 10,000 g / mol, still more preferably 500 g / mol to 8,000 g / mol, and especially 1,000 g / mol to 6,000 g / mol. Preferably, the polydispersity (PD) of the pyrrolidone-containing polymer (PP) is typically in the range of 1.1 to 5, preferably in the range of 1.1 to 4 and most preferably in the range of 1.1 to 3. The polydispersity (PD) is the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the pyrrolidone-containing polymer (PP). Preferably, the pyrrolidone-containing polymer (PP) has an amino value of 20 mg KOH / g to 500 mg KOH / g, more preferably 50 KOH / g to 450 KOH / g, and especially 150 KOH / g to 400 KOH / g, determined by titration. Suitable titration methods are known to the skilled person and are described in further detail in the examples of the present invention.

[0143] Unless stated otherwise, all weight % values ​​for components (A) and (B) and optionally component (C) are based on the total weight of the composition of the reaction mixture (rM2) before the start of its polymerization.

[0144] The phrase "the composition of the reaction mixture (rM2) before the start of polymerization" in the context of the present invention refers to the composition of the reaction mixture (rM2) before the components (A) and (B) and the optional component (C) present in the reaction mixture (rM2) start to react with one another (in other words, before the start of polymerization). Therefore, the components (A) and (B) and the optional component (C) present in the reaction mixture (rM2) are still in their unreacted form at this time. It goes without saying that during the polymerization of components (A) and (B) and the optional component (C), these components react with one another at least partially, with the result that the ratios of the components with one another change, just as the components present in the reaction mixture (rM2) change during the polymerization. These reactions are known to those skilled in the art.

[0145] As stated above for the % by weight, this molar ratio also relates to the molar ratio of component (A) to component (B) before the start of polymerization and thus before components (A) and (B) have reacted with one another.

[0146] The reaction mixture (rM2) may also comprise at least one catalyst as component (C).

[0147] As used in the context of the present invention, "at least one solvent" means exactly one catalyst or a mixture of two or more catalysts.

[0148] The terms "component (C)" and "at least one catalyst" are used synonymously in the context of the present invention and thus have the same meaning.

[0149] Suitable component (C) is a catalyst which catalyzes the reaction between component (A) and component (B). Examples of suitable catalysts are phosphoric acid, alkali metal dihydrogenphosphates, alkali metal hypophosphites, alkali metal hydrogen sulfates, tin octoate, titanium (IV) butoxide and bismuth-2,2-diphenyl undecanoate.

[0150] Therefore, the reaction mixture (rM2) preferably additionally comprises as component (C) at least one catalyst selected from the group consisting of phosphoric acid, alkali metal dihydrogenphosphates, alkali metal hypophosphites, alkali metal hydrogensulfates, tin octoate, titanium(IV) butoxide and bismuth-2,2-diphenylundecanoate.

[0151] Titanium(IV) butoxide is also known as Ti(OBu)4.

[0152] Alkali metal hypophosphites are preferred as component (C). Suitable alkali metal hypophosphites are known to the person skilled in the art and are selected, for example, from the group consisting of lithium hypophosphite, sodium hypophosphite and potassium hypophosphite. Sodium hypophosphite is particularly preferred as component (C).

[0153] For example, based on the sum of the weight percentages of components (A), (B) and (C), preferably based on the total weight of the reaction mixture (rM2), the reaction mixture (rM2) contains component (C) in a range of 0.1 wt % to 5 wt %, preferably in a range of 0.1 wt % to 3 wt %, and particularly preferably in a range of 0.1 wt % to 2 wt %.

[0154] It will be apparent to the skilled person that the weight percentages (wt %) of components (A) and (B) and optional component (C) generally add up to 100 wt %.

[0155] The polymerization of the reaction mixture (rM2) can be carried out in the presence of at least one solvent (S).

[0156] As used in the context of the present invention, "at least one solvent (S)" means both exactly one solvent (S) and a mixture of two or more solvents (S).

[0157] Suitable solvents (S) are known to those skilled in the art and are preferably solvents (S) that are inert to the components contained in the reaction mixture (rM2). Preferably, the at least one solvent (S) is selected from the group consisting of water, DMSO (dimethyl sulfoxide), NMP (N-methyl-2-pyrrolidone), butyl acetate, methyl ethyl ketone and mixtures thereof. Preferably, the at least one solvent (S) is water.

[0158] For example, the polymerization of the reaction mixture (rM2) is carried out at a temperature in the range of 50 to 300°C, preferably in the range of 70 to 250°C and particularly preferably in the range of 90 to 240°C.

[0159] The polymerization can be carried out as a one-step process or as a multistep process. These processes are known to the person skilled in the art and are described in more detail below with regard to the process for producing the pyrrolidone-containing polymer (PP).

[0160] During the polymerization, components (A) and (B) undergo a polycondensation reaction to form the pyrrolidone-containing polymer (PP).

[0161] In a preferred embodiment, the pyrrolidone-containing polymer (PP) is biodegradable. Preferably, the pyrrolidone-containing polymer (PP) has a biodegradability of more than 20%, more preferably more than 30%, still more preferably more than 40%, and in particular more than 45% after 28 days (determined according to OECD 301F). It is also preferred that the pyrrolidone-containing polymer (PP) has a biodegradability of 20% to 100%, more preferably 30% to 99%, still more preferably 40% to 99% or 40% to 90% after 28 days (determined according to OECD 301F).

[0162] Preferably, the pyrrolidone-containing polymer (PP) comprises at least one unit of the general formula (A)

[0163]

[0164] in

[0165] R 4 Selected from at least monosubstituted C2-C 20 -alkanediyl and C3-C 20 -cycloalkanediyl, wherein at least one substituent is C(=O)R 2 ,in

[0166] R 2Selected from Cl, Br and OR 3 The group consisting of

[0167] R 3 Choose from H, C1-C 10 -alkyl, C3-C 10 -cycloalkyl and C2-C 15 -alkenyl group.

[0168] R 4 Preferably selected from at least monosubstituted C2-C 20 -alkanediyl, wherein at least one substituent is C(=O)R 2 ,in

[0169] R 2 Selected from the group consisting of OH and Cl.

[0170] R 4 Most preferably selected from the group consisting of monosubstituted C3-C 10 -alkanediyl, wherein the substituent is C(=O)OH.

[0171] In a preferred embodiment, the powder coating comprises at least one inorganic pigment and / or at least one organic pigment.

[0172] Preferably, the powder coating comprises an inorganic pigment, more preferably selected from the group consisting of titanium dioxide, preferably in rutile form, barium sulfate, zinc oxide, zinc sulfide, basic lead carbonate, antimony trioxide, lithopone (zinc sulfide and barium sulfate), iron oxide, carbon black, graphite, zinc yellow, zinc green, ultramarine, manganese black, antimony black, manganese violet, Prussian blue and Paris green, especially titanium dioxide.

[0173] Preferably, the powder coating comprises an organic pigment, more preferably wherein the organic pigment is in the form of hollow organic particles and / or is based on a polymer comprising a nonionic ethylenically unsaturated monomer, preferably wherein the nonionic ethylenically unsaturated monomer is selected from the group consisting of styrene, acrylonitrile, methacrylamide, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate or mixtures thereof.

[0174] The (co)polymers are preferably composed of olefinically unsaturated compounds (units / monomers) in polymerized form. In this connection, it is understood that the (co)polymers are preferably provided as polymer dispersions, more preferably as aqueous polymer dispersions. The preparation of these addition-polymerizing compounds is usually carried out by metal complex-catalyzed, anion-catalyzed, cation-catalyzed and particularly preferably free-radical-catalyzed polymerization of olefinically unsaturated compounds, as is familiar to those skilled in the art.

[0175] The free-radically catalyzed polymerization of ethylenically unsaturated compounds will be familiar to the person skilled in the art and is carried out in particular by free-radically bulk, emulsion, solution, precipitation or suspension polymerization processes, particular preference being given to free-radically initiated aqueous emulsion polymerization.

[0176] The free-radical initiated emulsion polymerization of ethylenically unsaturated compounds (monomers) in aqueous medium is known [cf. Emulsion polymerization in Encyclopedia of Polymer Science and Engineering, Vol. 8, p. 659 ff. (1987); DC Blackley, in High Polymer Latices, Vol. 1, p. 35 ff. (1966); H. Warson, The Applications of Synthetic Resin Emulsions, Chapter 5, p. 246 ff. (1972); D. Diederich, Chemie in unserer Zeit, 24, pp. 135 to 142 (1990); Emulsion Polymerisation, Interscience Publishers, New York (1965); DE-A 40 03 422 and Dispersionen synthetischer Hochpolymerer, F. Springer-Verlag, Berlin (1969)]. Free-radical initiated aqueous emulsion polymerization is usually carried out by dispersing the monomers (usually with the use of dispersants such as emulsifiers and / or protective colloids) in an aqueous medium and polymerizing them with the aid of at least one water-soluble free-radical polymerization initiator. Usually, the residual content of unreacted monomers in the aqueous polymer dispersion obtained is reduced by chemical and / or physical aftertreatment, the polymer solids content is set to the desired value by dilution or concentration, or other conventional additives such as foam or viscosity-modifying additives are added to the aqueous polymer dispersion.

[0177] Possible monomers are, in particular, monomers which can be free-radically polymerized in a simple manner, for example ethylene, vinylaromatic monomers such as styrene, α-methylstyrene or o-chlorostyrene, vinyl acetate, acrylic acid, esters of acrylic acid and methacrylic acid with alkanols, the alkanols generally having 1 to 12, preferably 1 to 8 and in particular 1 to 4 carbon atoms, in particular methyl, ethyl, n-butyl, isobutyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl (for example hydroxyethyl methacrylate)), esters of acrylic acid and methacrylic acid with alkanes, the alkanes generally having 1 to 12, preferably 1 to 10 and in particular 1 to 8 carbon atoms (for example ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, 2-propylheptyl acrylate) and 1,3-butadiene. When preparing the polymer dispersion, the monomers mentioned usually form the main monomers, which total a proportion of ≥50% by weight, preferably ≥80% by weight and particularly preferably ≥90% by weight, based on the amount of all ethylenically unsaturated compounds used to prepare the polymer dispersion (total amount of monomers). In general, these monomers have only moderate to low solubility in water under standard conditions [20° C., 1 atm (=1.013 bar absolute pressure)].

[0178] In a preferred embodiment, the (co)polymer is an acrylic-styrene copolymer.

[0179] Suitably, the acrylic acid-styrene copolymer is obtainable by free radical polymerization of styrene and / or methylstyrene, especially styrene, with an acrylate selected from the group consisting of methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, hydroxyethyl methacrylate, 2-propylheptyl acrylate and mixtures thereof, especially selected from the group consisting of 2-ethylhexyl acrylate, hydroxyethyl methacrylate, butyl acrylate and mixtures thereof. In this connection, it is understood that methylstyrene generally refers to α-methylstyrene, β-methylstyrene, 2-methylstyrene, 3-methylstyrene and 4-methylstyrene, preferably to α-methylstyrene.

[0180] Preferably, the acrylic acid-styrene copolymer is obtainable by free radical polymerization of 15 to 50% by weight, more preferably 20 to 45% by weight, and especially 25 to 40% by weight of styrene and / or methylstyrene and 50 to 85% by weight, more preferably 55 to 80% by weight, and especially 60 to 75% by weight of at least one acrylic acid ester. In this connection, it is preferred that styrene is polymerized with at least one acrylic acid ester selected from the group consisting of methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, hydroxyethyl methacrylate, 2-propylheptyl acrylate and mixtures thereof, especially selected from the group consisting of 2-ethylhexyl acrylate, hydroxyethyl methacrylate, butyl acrylate and mixtures thereof.

[0181] In a preferred embodiment, the polymer dispersion comprises a styrene-butadiene based copolymer.

[0182] In a preferred embodiment, the polymer dispersion, preferably the aqueous polymer dispersion, has a solid polymer content determined according to DIN EN ISO 3251, based on the total weight of the aqueous polymer dispersion, of 20 to 70% by weight, more preferably 25 to 72% by weight, even more preferably 30 to 65% by weight, and in particular 50 to 62% by weight, and in particular 52 to 62% by weight.

[0183] In a preferred embodiment, the (co)polymer, preferably the acrylic acid-styrene copolymer, has a Tg (glass transition temperature) calculated using the Fox equation of -60°C to 20°C, preferably -50°C to 10°C, more preferably -40°C to 20°C, and especially -30°C to 10°C or -25°C to 0°C or -5°C to 20°C. According to Fox (cf. TGFox, Bull. Am. Phys. Soc. (Ser II) 1, 123,

[1956] and Ullmanns der technischen Chemie, Weinheim (1980), S. 17, 18), the following equation is a suitable approximation for the Tg of polymer dispersions:

[0184]

[0185] Where X 1 , X 2. …, X n is the mass fraction 1, 2, ..., n and Tg 1 , Tg 2 ,…,Tg nis the glass transition temperature in Kelvin of the homopolymer of each monomer 1, 2, ..., n. The respective Tg is known, for example, from Ullmann's Encyclopedia of Industrial Chemistry, VCH, Weinheim, Vol. A21 (1992), p. 169 and from J. Brandrup, EH Immergut, Polymer Handbook 3rd edition, J. Wiley, New York 1989.

[0186] In a preferred embodiment, the (co)polymer, preferably the acrylic acid-styrene copolymer, has an average particle size (D50 value) of the polymer particles measured by dynamic light scattering (e.g. determined according to ISO 22412:2008) of 50 nm to 1000 nm, preferably 100 nm to 900 nm, more preferably 150 nm to 750 nm.

[0187] The aqueous polymer dispersion may additionally comprise at least one surface-active compound. The surface-active compound is used to stabilize the aqueous dispersion of the polymer by keeping the polymer particles dispersed. The surface-active compound may be an emulsifier, a protective colloid or a mixture of the two. The emulsifier and the protective colloid differ from each other in their weight-average molar mass Mw. Emulsifiers typically have a weight-average molar mass Mw below 2000, while the weight-average molar mass Mw of protective colloids can be as high as 50000, especially above 2000 to as high as 50000. Typically, the amount of the surface-active compound is in the range of 0.1 wt % to 10 wt %, especially in the range of 0.5 wt % to 5 wt %, based on the total amount of polymer in the aqueous polymer dispersion.

[0188] Preferably, the surface-active compound comprises one or more emulsifiers. The emulsifier may be nonionic, anionic or cationic. In the case of an emulsifier mixture, their compatibility must be ensured, which can be evaluated by preliminary tests if in doubt. Typically, anionic emulsifiers are compatible with another anionic emulsifier or a nonionic emulsifier. Similarly, cationic emulsifiers are usually compatible with another cationic emulsifier or a nonionic emulsifier. Preferably, the emulsifier is an anionic emulsifier, a combination of two or more anionic emulsifiers or a combination of at least one anionic emulsifier and at least one nonionic emulsifier. Nonionic emulsifiers include, for example, ethoxylated C8-C8 emulsifiers with a degree of ethoxylation of 3 to 50 (=ethylene oxide units [EO]: 3-50). 36 Fatty alcohols and ethoxylated mono-, di- and tri-C4-C 12Examples of conventional nonionic emulsifiers are Eumulgin B grade (cetyl alcohol / stearyl alcohol ethoxylates, RTM BASF), Dehydol LS grade (fatty alcohol ethoxylates, EO units: 1-10, RTM BASF), Lutensol A grade (C 12 C 14 - Fatty alcohol ethoxylate, EO units: 3-8, RTM BASF), Lutensol AO grade (C 13 C 15 -oxo alcohol ethoxylates, EO units: 3-30), Lutensol AT grade (C 16 C 18 - fatty alcohol ethoxylates, EO units: 11-80), LutensolON grades (C10-oxo alcohol ethoxylates, EO units: 3-11) and LutensolTO grades (C 13 -oxo alcohol ethoxylate, EO units: 3-20). Here and hereinafter, the phrase "EO unit" means the average number of ethylene oxide repeating units in the emulsifier. Anionic emulsifiers include, for example, alkali metal salts of dialkyl esters of sulfosuccinic acid, C8-C 12 Alkali metal and ammonium salts of alkyl sulfates, C 12 -C 18 Alkali metal and ammonium salts of alkylsulfonic acids, C9-C 18 Alkali metal and ammonium salts of alkylarylsulfonic acids, ethoxylated C 12 -C 18 Sulfate monoesters of alkanols (EO units: 4-30) or ethoxylated (C4-C 12 Alkali metal salts and ammonium salts of sulfuric acid monoesters of (alkyl) phenol (EO units: 3-50).

[0189] Other anionic emulsifiers include, but are not limited to, fatty alcohol phosphates, alkylphenol phosphates, alkyl polyglycol ether phosphates, alkyl polyoxyalkylene phosphates and fatty alcohol ether phosphates and their salts, especially their alkali metal and ammonium salts, with particular preference for alkali metal salts such as sodium salts.

[0190] A comprehensive description of suitable emulsifiers can be found in Houben-Weyl, Methoden der organischen Chemie, Volume XIV / 1, Makromolekulare Stoffe, Georg-Thieme-Verlag, Stuttgart, 1961, pages 192 to 208.

[0191] Similar to the aforementioned emulsifiers, suitable protective colloids may be nonionic, anionic or cationic. Examples of protective colloids are poly(vinyl alcohol), poly(alkylene glycol), poly(acrylic acid) and its alkali metal salts, poly(methacrylic acid) and its alkali metal salts and gelatin derivatives. Anionic protective colloids may also be copolymers containing an appropriate amount of at least one anionic monomer in polymerized form, such as acrylic acid, methacrylic acid, maleic acid, 2-acrylamido-2-methylpropanesulfonic acid, p-vinylphenylsulfonic acid or their salt forms, preferably their alkali metal salts. Examples of cationic protective colloids are homopolymers and copolymers containing sufficient amounts of cationic monomers, especially monoethylenically unsaturated monomers having one or more N-protonated or N-alkylated amino groups.

[0192] Protective colloids differ from polymers dispersed in aqueous polymer dispersions in that they are water-soluble or water-dispersible. The term "water-soluble or water-dispersible" is understood to mean that the corresponding protective colloid can be dissolved or dispersed in deionized water at 20° C. and 1013 mbar in an amount of at least 10 g / L of polymer, so that the resulting aqueous solution has no particles of measurable size or particles of a size of at most 20 nm as determined by dynamic light scattering according to DIN 22412:2008.

[0193] A comprehensive description of suitable protective colloids can be found in Houben-Weyl, Methoden der organischen Chemie, Volume XIV / 1, Makromolekulare Stoffe, Georg-Thieme-Verlag, Stuttgart, 1961, pages 411 to 420.

[0194] As mentioned above, in a second aspect, the present invention relates to a powder coating comprising:

[0195] a) 5 to 30% by weight of at least one pigment;

[0196] b) 10 to 25 wt. % of at least one redispersible dispersion powder (RDP) comprising

[0197] i) at least one (co)polymer selected from the group consisting of acrylate polymers and acrylic-styrene copolymers, and

[0198] ii) at least one pyrrolidone-based (co)polymer;

[0199] c) 40% to 78% by weight of at least one filler;

[0200] d) 0 to 2 wt. % of at least one dispersant;

[0201] d) 0% to 2% by weight of at least one thickener; and

[0202] e) 0% to 2% by weight of at least one defoamer,

[0203] each based on the total dry weight of the powder coating, wherein the pyrrolidone-based (co)polymer is a pyrrolidone-containing polymer (PP) comprising at least one unit of the general formula (I) to (III)

[0204]

[0205]

[0206] wherein R is independently hydrogen, C1-C4-alkyl, or two groups R are linked to each other to form a six-membered ring;

[0207] X is -O- or -NR;

[0208] A is independently selected from C1-C 20 -alkanediyl, C3-C 20 -cycloalkanediyl and C6-C 20 - a group consisting of an arylene group,

[0209] Among them, C1-C 20 -alkanediyl is optionally interrupted by one or more non-adjacent oxygen atoms, sulfur atoms or functional groups -NR-, -CO-, -CO-O-, -CO-NR-, -SO- or -SO2-, in which the nitrogen atom is optionally protonated or quaternized,

[0210] Among them, C1-C 20 -alkanediyl and C3-C 20 -cycloalkanediyl optionally carries at least one selected from C(=O)R 2 and SO3H, where

[0211] R 2 Selected from Cl, Br and OR 3 The group consisting of

[0212] R 3 Choose from H, C1-C 10 Alkyl, C3-C 10 Cycloalkyl and C2-C 15 The group consisting of alkenyl groups,

[0213] Among them, C6-C 20 -arylene is optionally inserted with oxygen, sulfur, -NR-, -SO- or -SO2- and is optionally substituted with -COOH or -SO3H or a mixture of these groups;

[0214] Z is a group of formula (IV)

[0215]

[0216] Where B is C1-C 20 -alkanediyl, C6-C 20 -cycloalkanediyl or a mixture of such groups, C1-C 20 -alkanediyl optionally interrupted by one or more non-adjacent oxygen atoms, sulfur atoms or functional groups -NR-, -CO-, -CO-O-, -CO-NR-, -SO- or -SO2-, and optionally carrying an additional functional group -COOH or -SO3H, in which the nitrogen atom in the functional group -NR- is optionally protonated or quaternized

[0217] Alternatively, Z is a mixture of a group of formula (IV) and a group A.

[0218] Preferred embodiments, such as preferred embodiments of the at least one (co)polymer and the pyrrolidone-containing polymer (PP), have already been disclosed above for the use of pyrrolidone-based (co)polymers as spray drying aids and are similarly applicable to powder coatings. Particularly preferred embodiments are disclosed again below.

[0219] In a preferred embodiment, the powder coating comprises

[0220] a) 8 to 20% by weight of at least one pigment;

[0221] b) 10 to 19 wt. % of at least one redispersible dispersion powder (RDP) comprising

[0222] i) at least one (co)polymer selected from the group consisting of acrylate polymers and acrylic acid-styrene copolymers, preferably acrylic acid-styrene copolymers, and

[0223] ii) at least one pyrrolidone-based (co)polymer;

[0224] c) 55 to 78% by weight of at least one filler;

[0225] d) 0.2% to 2% by weight of at least one dispersant;

[0226] d) 0.5% to 2% by weight of at least one thickener; and

[0227] e) 0.5 to 2% by weight of at least one defoamer,

[0228] Each is based on the total dry weight of the powder coating.

[0229] Powder coatings comprising the ingredients defined above are particularly suitable as interior coatings.

[0230] In a preferred embodiment, the powder coating comprises

[0231] a) 21 to 30% by weight of at least one pigment;

[0232] b) 15 to 25 wt. % of at least one redispersible dispersion powder (RDP), the redispersible dispersion powder comprising

[0233] i) at least one (co)polymer selected from the group consisting of acrylate polymers and acrylic acid-styrene copolymers, preferably acrylic acid-styrene copolymers, and

[0234] ii) at least one pyrrolidone-based (co)polymer;

[0235] c) 40% to 54% by weight of at least one filler;

[0236] d) 0.2% to 2% by weight of at least one dispersant;

[0237] d) 0.5% to 2% by weight of at least one thickener; and

[0238] e) 0.5 to 2% by weight of at least one defoamer,

[0239] Each is based on the total dry weight of the powder coating.

[0240] Powder coatings comprising the ingredients defined above are particularly suitable as exterior coatings.

[0241] In various embodiments, the pyrrolidone-containing polymer (PP) is obtainable by polymerization of a reaction mixture (rM1), wherein the reaction mixture (rM1) comprises at least the following components:

[0242] (A) at least one itaconic acid derivative, preferably wherein component (A) is selected from the group consisting of itaconic acid, itaconic anhydride, itaconic esters and itaconic acid halides, and

[0243] (B) at least one diamine, preferably wherein the diamine is selected from the group consisting of ethylenediamine,

[0244] 1,3-diaminopropane, 1,4-diaminobutane, 1,5-pentanediamine, 1,6-diaminohexane,

[0245] 1,7-diaminoheptane, 1,8-diaminooctane and 1,9-diaminononane, more preferably, is selected from ethylenediamine and 1,5-pentanediamine.

[0246] In a preferred embodiment, the reaction mixture (rM1) comprises at least two diamines, preferably selected from the group consisting of ethylenediamine, 1,3-diaminopropane, 1,4-diaminobutane, 1,5-pentanediamine, 1,6-diaminohexane and 1,7-diaminoheptane, and in particular wherein the reaction mixture (rM1) comprises ethylenediamine and 1,5-pentanediamine.

[0247] In a preferred embodiment, the pyrrolidone-containing polymer (PP) is obtainable by polymerization of a reaction mixture (rM2), wherein the reaction mixture (rM2) comprises at least the following components:

[0248] (A) at least one itaconic acid derivative, preferably wherein component (A) is selected from the group consisting of itaconic acid, itaconic anhydride, itaconic esters and itaconic acid halides, and

[0249] (B) at least one amino acid of the general formula (1)

[0250] H2N–R 1 –C(=O)–R 2 (1)

[0251] in

[0252] R 1 Selected from at least monosubstituted C2-C 20 -alkanediyl and at least monosubstituted C3-C 20 - the group consisting of cycloalkanediyl, wherein the substituent is NH2;

[0253] R 2 Selected from Cl, Br and OR 3 The group consisting of

[0254] R 3 Choose from H, C1-C 10 Alkyl, C3-C 10 Cycloalkyl and C2-C 15 The group consisting of alkenyl groups, preferably wherein component (B) is selected from the group consisting of L-lysine, D-lysine and a racemic mixture of L-lysine and D-lysine.

[0255] In a preferred embodiment, the at least one pigment is an inorganic white pigment, preferably selected from the group consisting of titanium dioxide, preferably in rutile form, barium sulfate, zinc oxide, zinc sulfide, basic lead carbonate, antimony trioxide and lithopone (zinc sulfide and barium sulfate) or and an inorganic colored pigment, more preferably selected from the group consisting of iron oxide, carbon black, graphite, zinc yellow, zinc green, ultramarine, manganese black, antimony black, manganese violet, Prussian blue and Paris green, especially titanium dioxide.

[0256] In a preferred embodiment, the at least one pigment is an organic pigment. Suitable organic color pigments are, for example, sepia, gamboge, Cassel brown, toluidine red, para red, Hansa yellow, indigo, azo dyes, anthraquinones and indigoid dyes as well as dioxazines, quinacridones, phthalocyanines, isoindolinones and metal complex pigments. Also useful are BASF SE's Brands, e.g. yellow, Brown and In a preferred embodiment, the powder coating comprises an organic pigment, wherein the organic pigment is in the form of hollow organic particles and / or is based on a polymer comprising a nonionic ethylenically unsaturated monomer, preferably wherein the nonionic ethylenically unsaturated monomer is selected from the group consisting of styrene, acrylonitrile, methacrylamide, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate or mixtures thereof.

[0257] In various embodiments, the inorganic pigments and organic pigments disclosed above may also be used in combination.

[0258] Suitable fillers include, for example, matting agents, which significantly reduce the gloss in the desired manner. Matting agents are usually transparent and can be both organic and inorganic. Inorganic fillers based on silica are most suitable and are widely commercially available. Examples are WR Grace & Company's Brands and Evonik Industries AG. Brand. Organic matting agents such as Brand and The brand is obtained from BYK-Chemie GmbH and is marketed under the name Deuteron The brand is available from Deuteron GmbH. Fillers suitable for emulsion paints also include aluminosilicates such as feldspar; silicates such as kaolin, talc, mica, magnesite; alkaline earth metal carbonates such as calcium carbonate (for example in the form of calcite or chalk), magnesium carbonate, dolomite; alkaline earth metal sulfates such as calcium sulfate; silicon dioxide, etc. Finely divided fillers are naturally preferred in paints. Fillers can be used as individual components. However, in practice, filler mixtures have been found to be particularly advantageous, examples being calcium carbonate / kaolin and calcium carbonate / talc. Gloss paints usually include only minimal amounts of very finely divided fillers or are completely free of fillers.

[0259] Finely divided fillers may also be used to enhance opacity and / or conserve white pigment. Blends of fillers and color pigments are preferably used to control opacity and chroma (color intensity) of hue / color.

[0260] In a preferred embodiment, the at least one filler is selected from the group consisting of calcium carbonate, precipitated calcium carbonate, talc, mica, silica, aluminum silicate, nepheline syenite, clay, calcined clay, feldspar and mixtures thereof.

[0261] Suitable dispersants are, for example, sodium polyphosphates, potassium polyphosphates, ammonium polyphosphates, alkali metal and ammonium salts of (meth)acrylic acid copolymers or maleic anhydride copolymers, polyphosphonates (such as sodium 1-hydroxyethane-1,1-diphosphonate) and naphthalenesulfonates, especially the sodium salts thereof.

[0262] In a preferred embodiment, the at least one dispersant is a carboxylic acid copolymer sodium salt in water or a copolymer of maleic acid and an olefin as sodium salt, preferably a carboxylic acid copolymer sodium salt in water. The dispersant may be present in the powder coating in an amount of 0.1 wt % to 2 wt %, preferably 0.2 wt % to 1 wt %, based on the total weight of the formulation. Preferably, the amount is adjusted according to the filler used.

[0263] Suitable defoamers include, for example but not limited to, hydrophobic materials such as silicones, polysiloxanes, mineral oils, vegetable oils and white oils, which are often provided in powder form in combination with a surface-active substance (e.g. FoamStar PB 2922) and usually bound to a carrier substance such as silica (e.g. Agitan P 804).

[0264] In a preferred embodiment, the at least one defoaming agent is a modified polysiloxane.

[0265] Useful thickeners include, for example, associative thickeners, such as polyurethane thickeners. The amount of thickener is preferably less than 2.5% by weight, more preferably less than 1.5% by weight of thickener, based on the coating solids content. Further guidance on wood coating formulations can be found in the detailed description of authors M. Schwartz and R. Baumstark in "Water based acrylates for decorative coatings" ISBN 3-87870-726-6. Other suitable thickeners include, for example, acrylic thickeners, cellulose ethers, chemically modified cellulose derivatives (cellulose products - hydroxyethyl cellulose (HEC), carboxymethyl cellulose (CMC), hydroxypropyl methylcellulose, methylcellulose, hydroxypropyl cellulose, ethyl hydroxyethyl cellulose and other chemically substituted cellulose macromolecules), hydrophobically modified polyethers (HMPE), gums, sugars, polysaccharides and polyvinyl alcohol.

[0266] In a preferred embodiment, the at least one thickener is hydroxyethylcellulose (HEC), preferably having a weight average molecular weight (Mw; determined by gel permeation chromatography (GPC) with a 0.05 M aqueous ammonium formate / methanol mixture = 80:20 (volume parts) as eluent) of 1,000 to 100,000 g / mol, more preferably 5,000 to 60,000 g / mol, still more preferably 10,000 to 50,000 g / mol, and especially 15,000 to 25,000 g / mol.

[0267] The powder coating may also contain a film former. Suitable film formers include, but are not limited to, and for example from BASF SE under the trade name and and from Dow Chemicals under the trade name Commercially available glycol ethers and esters. The amount is preferably <10% by weight and more preferably <5% by weight, based on the total weight of the formulation. It is also possible to formulate completely without solvents or such film formers.

[0268] Wetting agents may also be included in the powder coatings of the present invention. Suitable wetting agents include, but are not limited to, nonionic surfactants, such as nonionic ethoxylated fatty alcohol-based surfactants or nonionic propoxylated fatty alcohol-based surfactants (e.g., Lumiten N-OG). The wetting agent may be present in the powder coating in an amount of 0.1 wt % to 2 wt %, preferably 0.2 wt % to 1 wt %, based on the gross weight of the formulation. Preferably, the amount is adjusted according to the filler used.

[0269] Further information on coating formulations can be found in the following references: the textbook “Additives for Water-borne Coatings” by Wernfried Heilen et al.; Vincentz-Verlag 2021; 978-3-7486-0486-O (ISBN) and Waterbased Acrylates for Decorative Coatings from Manfred Schwartz, Roland Baumstark; Vincentz Press, 2001, Chapter 2).

[0270] As mentioned above, the present invention in a third aspect relates to a method for making a coating or producing a usable coating, which method comprises mixing the powder coating described herein with a certain amount of a suitable solvent (such as water) to adjust the solid content preferably to 45 wt % to 70 wt %, more preferably 50 wt % to 65 wt %, based on the total weight of the coating.

[0271] The coatings of the invention are produced in a known manner by blending the components in a conventional mixer. A tried and tested procedure is to first prepare an aqueous paste or dispersion of pigment, water and optional auxiliaries and then to mix only the polymer binder, i.e. an aqueous dispersion of a polymer, with the pigment paste and the pigment dispersion, respectively.

[0272] The coating materials of the invention can be applied to the substrate in a customary manner, for example by brushing, spraying, dipping, rolling or knife coating.

[0273] Preferred embodiments, such as preferred embodiments of the at least one (co)polymer and the pyrrolidone-containing polymer (PP), have already been disclosed above for the inventive use of pyrrolidone-based (co)polymers as spray drying aids and apply analogously to the coatings of the invention, and vice versa. Particularly preferred embodiments are mentioned again below.

[0274] Preferably, the method comprises stirring the mixture.

[0275] Preferably, the method comprises mixing the above powder coating with deionized water.

[0276] The present invention also discloses and encompasses a coating obtainable by or through the above-mentioned method for making a coating.

[0277] Example

[0278] The present invention is described in more detail by the following examples, which are intended to be illustrative rather than limiting.

[0279] Materials and methods

[0280] Itaconic acid was purchased from Sigma-Aldrich (>99% purity).

[0281] L-Lysine (using ADM, 50% aqueous solution, unless otherwise stated, purity >98%)

[0282] The weight average molecular weight (Mw) was determined by gel permeation chromatography (GPC) using a 0.05 M aqueous ammonium formate / methanol mixture = 80:20 (volume parts) as the eluent.

[0283] The number average molecular weight (Mn) was determined by gel permeation chromatography (GPC) using a 0.05 M aqueous ammonium formate / methanol mixture = 80:20 (volume parts) as the eluent.

[0284] The molecular weight (mass average molar mass (Mw) and number average molar mass (Mn)) of the polymer was determined as follows: a sample was prepared for the determination of the molar mass by dissolving the copolymer solution in a GPC eluent so that the polymer concentration in the GPC eluent was 0.5 wt %. Afterwards, the solution was filtered through a syringe filter with a polyethersulfone membrane and a pore size of 0.45 μm. The injection volume of the filtrate was 50 μL-100 μL. The average molecular weight was determined on a Waters GPC instrument with a model name of Alliance 2690 with a UV detector (Waters 2487) and an RI detector (Waters 2410). The following settings and conditions were used:

[0285] Column: Shodex SB-G guard column and Shodex OHpak SB of SB-800HQ series

[0286] 804HQ and 802.5HQ (PHM gel, 8x300mm, pH 4.0 to 7.5)

[0287] Eluent: 0.05M aqueous ammonium formate / methanol mixture = 80:20 (volume fractions)

[0288] Flow rate: 0.5mL / min

[0289] Temperature: 50℃.

[0290] Injection: 50μL to 100μL

[0291] Detection: RI and UV

[0292] Depending on the nature of the copolymers, their molecular weights were determined relative to poly(ethylene glycol) and poly(ethylene oxide) or polyacrylic acid standards from PSS Polymer Standards Service GmbH. The molecular weight distribution curve of the polyacrylic acid standards was determined by light scattering.

[0293] Amino value :

[0294] The amino value (in mg KOH / g) is determined by titration. A potentiometric titrator (potentiograph) equipped with a Dosimat with a 10 ml interchangeable burette and a combined glass-Ag / AgCl-electrode is used, for example a titration processor 726 model with a Dosimat 685 (Metrohm). In a 100 ml beaker, about 0.1 g to 1.0 g of sample (the exact mass is selected according to the expected amine value) is mixed with 50 ml of glacial acetic acid to obtain a solution. The solution is titrated with 0.1 N trifluoromethanesulfonic acid (standard solution in glacial acetic acid, c(CF3SO3H)=0.1 mol / l) until a potential inflection point of about 600 mV is reached. A blank value is determined using a solvent.

[0295] Calculation of amine value :

[0296]

[0297] in

[0298] Amine value: fraction of total amines calculated in mg KOH / g

[0299] VP: Consumption of standard solution until the inflection point [ml]

[0300] VB: Consumption of standard solution in blank value titration [ml]

[0301] t: titer of standard solution

[0302] c: concentration of standard solution [= 0.1 mol / l]

[0303] E: Weight of sample taken out [g]

[0304] 56.1 is the molar mass of KOH [g / mol]

[0305] For the Examples and Comparative Examples, the following materials and raw materials were used:

[0306] Spray Drying Aids :

[0307] Spray drying additives 1 :

[0308] Commercially available polyvinylpyrrolidone (PVP) is manufactured by BASF and sold under the trade name K 17 was obtained. The molecular weight of the polymer is M W 9kDa and M N 2kDa.

[0309] Spray drying additive 2 :

[0310] Commercially available polyvinylpyrrolidone (PVP) is manufactured by Sigma-Adrich and is available under the trade name PVP10. The molecular weight of this polymer is M W 10kDa.

[0311] Spray drying additives 3 :

[0312] Commercially available polyvinylpyrrolidone (PVP) is manufactured by BASF and sold under the trade name K 30 was obtained. The molecular weight of the polymer is M W 50 kDa and M N 14kDa.

[0313] Spray drying additives 4 :

[0314] Commercially available polyvinylpyrrolidone (PVP) is manufactured by BASF and sold under the trade name K 90 was obtained. The molecular weight of the polymer is M W 1400 kDa and M N 325kDa.

[0315] Spray drying additives 5 :

[0316] A commercially available copolymer of vinyl pyrrolidone and vinyl acetate is manufactured by BASF and marketed under the trade name VA 64 was obtained. The molecular weight of the polymer is M W 65kDa and M N 15kDa.

[0317] Spray drying additive 6 :

[0318] In a reaction vessel (four-necked flask) equipped with a reflux condenser, agitator, a thermometer, a dropping funnel and nitrogen bubbling, a solution of 520.4 g of itaconic acid, 123.6 g of ethylenediamine and 500 mL of water was stirred and refluxed for one hour. Then, 208.5 g of 1,5-pentanediamine was added. Water was removed by a distillation apparatus at normal pressure and later by applying a vacuum. In parallel, the reaction mixture was slowly heated to 180°C. Under a vacuum of <2 mbar, the reaction was continued until the agitator showed a torque of 20 Ncm. The K value of the polymer obtained was 20.6, and the molecular weight M W is ~5020g / mol and M N It is ~2350g / mol.

[0319] Spray drying additives 7 :

[0320] In a manner similar to the synthesis procedure described for spray drying aid 1, 339.9 g of itaconic acid and 133.5 g of 1,5-pentanediamine were used to synthesize spray drying aid 2. Afterwards, 39.5 g of ethylenediamine and 67.1 g of 1,5-pentanediamine were added. The same treatment as described for spray drying aid 1 was then carried out. The K value of the polymer obtained was 18.6 and the molecular weight M W is ~4690g / mol and M N It is ~2190g / mol.

[0321] Spray drying aid 8 :

[0322] In a manner similar to the synthesis procedure described for spray drying aid 1, spray drying aid 3 was synthesized using 390.3 g of itaconic acid and 92.0 g of ethylenediamine. Thereafter, 46.0 g of ethylenediamine and 78.2 g of 1,5-pentanediamine were added. The same treatment as described for spray drying aid 1 was then carried out. The K value of the polymer obtained was 16.5, and the molecular weight M W is ~4360g / mol and M N It is ~2010g / mol.

[0323] Spray drying additives 9 :

[0324] 526.32g of 50% aqueous solution of L-Lysine (1.8mol) was placed in a 2L four-necked flask equipped with a stirrer, a condenser column, a thermometer and a nitrogen inlet. 117.09g of itaconic acid (0.9mol) was added to the L-Lysine solution. The mixture was heated to boiling point and kept under reflux for 10 hours under stirring and an inert atmosphere (N2 flow). Then, the temperature of the external heat source was raised according to the following curve: at 150°C for 1 hour, at 160°C for 1 hour, at 170°C for 1 hour and at 180°C for 1 hour, while water was distilled off. The warm reaction melt was collected in an aluminum container. At room temperature, a solid material was obtained. The amino value of the polymer obtained was 308mg KOH / g. The molecular weight M of the polymer was 2.377 W / m3. W is ~2410g / mol and M N It is ~2175g / mol.

[0325] (Reference) Spray Drying Aid 10 :

[0326] Commercially available polyacrylamide (PAM; catalog number 22581) in water, manufactured by Polysciences Inc. The polymer has a solids content of 50 wt% and a molecular weight M of -10,000 g / mol. W .

[0327] (Reference) Spray Drying Aid 11 :

[0328] In a reaction vessel equipped with a reflux condenser, a stirrer, a thermometer, a dropping funnel and a nitrogen sparge, an initial charge of 280 g of water and 195 g of Na-2-acrylamido-2-methylpropanesulfonic acid (AMPS) was heated to 18° C. While stirring, 70 g of a 50% sodium hydroxide solution was added dropwise at 18° C. Subsequently, 68 g of acrylic acid, 2.8 g of 2,2'-azobis(2-methylpropionamidine) dihydrochloride (Wako V50) and 4 g of mercaptoethanol were metered over 10 minutes while stirring. The reaction solution was stirred at 70° C. to 80° C. for 1.5 hours and then cooled to room temperature. The resulting product was a solids content of 48.1% by weight, a pH of 0.8 and a molecular weight of M W It is a transparent polymer solution of about 8400 g / mol.

[0329] (Reference) Spray Drying Aid 12 :

[0330] In a reaction vessel equipped with a reflux condenser, a stirrer, a thermometer, a dropping funnel and a nitrogen sparge, an initial charge of 350 g of water and 313 g of Na-2-acrylamido-2-methylpropanesulfonic acid (AMPS) was heated to 18° C. While stirring, 112 g of a 50% sodium hydroxide solution was added dropwise at 18° C. Subsequently, 27 g of acrylic acid, 2.8 g of 2,2'-azobis(2-methylpropionamidine) dihydrochloride (Wako V50) and 6 g of mercaptoethanol were metered over 14 minutes while stirring. The reaction solution was stirred at 70° C. to 80° C. for 1.5 hours and then cooled to room temperature. The resulting product was a solids content of 48.5% by weight, a pH of 0.8 and a molecular weight of M W It is a transparent polymer solution of about 7400 g / mol.

[0331] (Reference) Spray drying aid 13: 4-88

[0332] Commercially available partially saponified polyvinyl alcohol (PVOH) is a solid having a degree of hydrolysis of 86.7 mol% to 88.7 mol%, a non-volatile fraction of 97.5% ± 2.5% (measured after drying for 3 hours at 105°C according to DIN 53189 / JIS K 6726), and a viscosity of 3.5 mPa*s to 4.5 MPa*s as a 4% aqueous solution at 20°C (according to DIN 53015 / JIS K 6726). The polymer is manufactured by Kuraray and is available under the trade name 4-88 obtained.

[0333] (Reference) Spray Drying Aid 14 :

[0334] A polyacid based on the monomers methacrylic acid and 2-methyl-2-propene-1-sulfonic acid. The polyacid has a molecular weight M of ∼1400 g / mol. W And synthesized as described in US2020 / 0207671 A1, page 10, paragraphs

[0234] to

[0235] .

[0335] (Reference) Spray Drying Aid 15 :

[0336] The pH is ~2 and the molecular weight M W Sokalan PA 25XS is a 5000 g / mol polyacrylic acid manufactured by BASF and available under the trade name Sokalan PA 25XS.

[0337] (Reference) Spray Drying Aid 16 :

[0338] Phenolsulfonic acid-formaldehyde condensation products with a molecular weight of MW ∼8000 g / mol were synthesized as described in WO 98 / 03576 A1, page 14, line 42 to page 15, line 12.

[0339] Aqueous dispersion

[0340] Dispersion 1 :

[0341] The dispersion was synthesized according to styrene-acrylate as described in US 2020 / 0207671 A1: Dispersion 1 on page 9. The polymer obtained had a solids content of 55% by weight, a glass transition temperature of −15° C. and a particle size of about 600 nm.

[0342] Dispersion 2 :

[0343] This dispersion is based on the same composition as Dispersion 1 and additionally contains 3 parts per hundred monomer (pphm) of M W The obtained polymer has a solid content of 54.6% by weight, a glass transition temperature of -15°C, and a particle size of about 730 nm.

[0344] Dispersion 3 :

[0345] The dispersion was synthesized according to a styrene-acrylate dispersion prepared by emulsion polymerization as described in WO 2013 / 117465 A1: Example "Polymerization Dispersion D" on pages 19-20. The dispersion had a solids content of 57% by weight, a glass transition temperature of -13°C and a particle size of 230 nm.

[0346] Dispersion 4 :

[0347] The dispersion is based on styrene-acrylate. The solids content of the polymer is 60% by weight, the glass transition temperature is -8°C to -10°C, and the particle size is about 550nm. The dispersion contains 68.5pphm n-butyl acrylate, 28.5pphm styrene and 3pphm acrylic acid. The dispersion is stabilized by 2 wt% emulsifier (fatty alcohol (C12-C14) ether sulfate with a degree of ethoxylation of ~30 EO units).

[0348] Spray drying of dispersions

[0349] A) Preparation of Spray Drying Feed :

[0350] To prepare the dispersion to be spray dried, the selected aqueous polymer dispersion (a as described above) is mixed with the selected spray drying aid (selected from spray drying aids No. 1 to No. 16 as described above) while stirring. In addition, the spray feed may be mixed with a dispersing aid such as a sodium salt of a carboxylic acid copolymer in water (Dispex CX 4320) or a copolymer of maleic acid and olefin as a sodium salt of a maleic acid / olefin copolymer in powder form. The amount of the spray drying aid used is shown in Table 1.

[0351] The concentration of the dispersion to be dried was adjusted using additional water to 44% by weight, relative to the solids content in the spray feed.

[0352] B) Spray Drying of Dispersions :

[0353] Spray drying was carried out by a commercially available laboratory-scale spray dryer (Niro atomizer from Niro) using nitrogen as drying gas. The aqueous dispersion to be dried was sprayed through a two-fluid nozzle. The inlet temperature of the drying gas was 130° C. to 140° C. Its outlet temperature was 60° C. to 70° C. The first antiblocking agent (1% by weight of hydrophobic silica powder based on the total amount of all components of the final product) was fed into the drying chamber through a further nozzle.

[0354] After the obtained powder was taken out from the spray dryer, it was mixed with 9-10 wt% (based on the total amount of all components of the final product) of a second antiblocking agent (talc).

[0355] Preliminary test: Determination of redispersibility

[0356] Compositions consisting of dispersions containing the spray drying aids (SDAs) specified in Table 1 were used to produce films and their redispersion was tested. For this purpose, liquid dispersions (5 g solid) in 10 mL-15 mL water were mixed with the described amounts of the respective SDA and dried at room temperature for two days. Approximately 0.5 g of film was placed in 10 mL of distilled water while stirring (200 rpm) at room temperature. Upon rapid redispersion within a few minutes, it was found that these dispersions also have excellent spray drying capabilities and redispersible powders (RDPs) were obtained.

[0357] The redispersion assessment is as follows:

[0358] Complete redispersion within a few minutes: Very good

[0359] Almost complete redispersion within a few minutes: Good

[0360] Incomplete redispersion (some film / powder still evident): Moderate

[0361] Most of the film / powder is insoluble or not redispersible: Poor

[0362] Table 1. Redispersibility of different combinations of dispersions and SDA as films and as RDP

[0363]

[0364]

[0365] *sc=solid content

[0366] **nd = not determined

[0367] When the pre-test was better than or equal to a moderately redispersible film in water, the combination was only spray dried. As can be seen from Table 1, the combination of styrene-acrylate dispersions with homopolymers and copolymers based on vinyl pyrrolidone produced redispersible films and redispersible powders. This was also true for the combination of styrene-acrylate dispersions with the polycondensates of itaconic acid and diamine / lysine.

[0368] Although polyvinyl alcohol (PVOH, spray drying aid 13) is a common protective colloid and spray drying additive for dispersions based on copolymers of vinyl acetate and ethylene (EVA) and for terpolymers of vinyl acetate, ethylene and vinyl ester, the combination of styrene-acrylate dispersions used here with polyvinyl alcohol (PVOH) as SDA is not suitable and neither redispersible films nor redispersible dispersion powders are obtained.

[0369] Possible explanations: For the compatibility of the dispersion with SDA, the nature of the stabilization is important and also the presence / absence of a protective colloid (such as polyvinyl alcohol; PVOH) during the emulsion polymerization can play a role. In case of using PVOH as protective colloid during the emulsion polymerization and as SDA, a suitable combination for spray drying is obtained.

[0370] Other amide based SDAs, such as polyacrylamide (Spray Drying Aid 10) and copolymers containing AMPS (Spray Drying Aids 11 and 12), showed neither redispersible films nor redispersible dispersion powders with the styrene-acrylate dispersions.

[0371] The polyacid based SDAs (Spray Drying Aids 14, 15 and 16) in combination with styrene-acrylate dispersions showed very good redispersible films and powders.

[0372] Application Testing

[0373] The effect of redispersible powders on wet scrub resistance in coating formulations was investigated according to EN 13300. Therefore, a dry formulation was produced according to Table 2 and mixed with 365.00 parts by weight of deionized water.

[0374] Table 2: Coating formulation (dry)

[0375] Function / Components Weight <![CDATA[Basic thickener, HEC, M W 20000]]> 4.00 Dispersant (sodium salt of carboxylic acid copolymer in water; Dispex CX 4320) 3.00 Defoaming agent (modified polysiloxane) 4.00 Rutile; Titanium dioxide 60.00 Filler, fine aluminum silicate 20.00 Filler, precipitated calcium carbonate PCC 50.00 Flaky filler, talc 90.00 Filler, calcite 2μm 80.00 Filler, calcite 5μm 230.00 Dispersion powder 94.00(latex content)

[0376] If the dispersant has been co-spray dried with the dispersion, the dispersant has been removed from the formulation.

[0377] Wet scrub resistance was studied according to EN 13300. The lower the abrasion after 200 cycles, the better the coating formulation. Aqueous dispersions for RDP show the lowest abrasion, since there are no additional water-soluble polymers (SDA) that have no function for the coating system.

[0378] Table 3: Wet scrub resistance of formulations containing RDP; "X" indicates neither the combination nor SDA was added .

[0379] Example combination Dispersion SDA Scrub [μm]*** Reference 1 X 1 X 19 Reference 2 X 4 X 36 Example 1 1 1 1 50 Example 2 2 1 2 42 Example 3 3 1 3 33 Example 4 4 1 4 nd** Example 5 5 1 1 39 Example 6 6 1 3 54 Example 7 7 1 1 40 Example 8 8 1 3 31 Example 9 9 1 1 43 Example 10 10 1 3 35 Embodiment 11 11 1 1 56 Example 12 12 1 3 27 Embodiment 13 13 1 5 73 Embodiment 14 14 4 5 58 Embodiment 15 15 1 6 32 Example 16 16 1 6 29 Embodiment 17 17 1 7 nd** Embodiment 18 18 1 7 45 Embodiment 19 19 1 8 46 Embodiment 20 20 2 9 46 Embodiment 21 21 3 6 36 Embodiment 22 22 4 9 63 Reference Example 23 36 1 14 71 Reference Example 24 37 1 15 130 Reference Example 25 38 1 16 46

[0380] **nd = not determined

[0381] ***After 200 cycles

[0382] In the case of phenolsulfonic acid-formaldehyde condensation products as SDA (spray drying aid 16), the resulting RDP was brown in color and therefore unsuitable for powder coatings.

[0383] In the case of polyacid-based SDAs (spray drying aids 14 and 15), the resulting RDP is acidic and must be neutralized in the coating formulation, as described in DE 19601699 A1. In addition, the wet scrub resistance is poor compared to the polymers of the invention. If the polycarboxylic acid is neutralized before spray drying the dispersion, the resulting dispersion powder is poorly redispersible, as described in WO 2018 / 224519.

[0384] In summary, the powder coatings of the present invention surprisingly offer well-balanced properties with respect to their redispersibility, wet scrub resistance and visual appeal.

Claims

1. Use of a pyrrolidone-based (co)polymer as a spray drying aid in a process for producing a powder coating comprising at least one redispersible dispersion powder (RDP), the redispersible dispersion powder comprising i) a (co)polymer selected from the group consisting of acrylate polymers, acrylic acid-styrene copolymers, styrene-butadiene based copolymers and mixtures thereof, and ii) The pyrrolidone-based (co)polymers.

2. The method according to claim 1, wherein the pyrrolidone-based (co)polymer is a homopolymer of N-vinylpyrrolidone or a copolymer of N-vinylpyrrolidone and vinyl acetate.

3. The use according to claim 1, wherein the at least one pyrrolidone-based (co)polymer is a pyrrolidone-containing polymer (PP) comprising at least one unit of the general formula (I) to (III): wherein R is independently hydrogen, C1-C4-alkyl, or two groups R are linked to each other to form a six-membered ring; X is -O- or -NR; A is independently selected from C1-C 20 -alkanediyl, C3-C 20 -cycloalkanediyl and C6-C 20 - a group consisting of an arylene group, Wherein the C1-C 20 -alkanediyl is optionally interrupted by one or more non-adjacent oxygen atoms, sulfur atoms or functional groups -NR-, -CO-, -CO-O-, -CO-NR-, -SO- or -SO2-, in which the nitrogen atom is optionally protonated or quaternized, Wherein the C1-C 20 -alkanediyl and the C3-C 20 -cycloalkanediyl optionally carries at least one selected from C(=O)R 2 and SO3H, where R 2 Selected from Cl, Br and OR 3 The group consisting of R 3 Choose from H, C1-C 10 -alkyl, C3-C 10 Cycloalkyl and C2-C 15 -alkenyl group, Wherein the C6-C 20 -arylene is optionally inserted with oxygen, sulfur, -NR-, -SO- or -SO2- and is optionally substituted with -COOH or -SO3H or a mixture of these groups; Z is a group of formula (IV) Where B is C1-C 20 -alkanediyl, C6-C 20 -cycloalkanediyl or a mixture of such groups, wherein the C1-C 20 -alkanediyl optionally interrupted by one or more non-adjacent oxygen atoms, sulfur atoms or functional groups -NR-, -CO-, -CO-O-, -CO-NR-, -SO- or -SO2-, and optionally carrying an additional functional group -COOH or -SO3H, in which the nitrogen atom is optionally protonated or quaternized Alternatively, Z is a mixture of a group of formula (IV) and a group A.

4. The method according to claim 3, wherein the pyrrolidone-containing polymer (PP) is obtainable by polymerization of a reaction mixture (rM1), wherein the reaction mixture (rM1) comprises at least the following components: (A) at least one itaconic acid derivative, preferably wherein component (A) is selected from the group consisting of itaconic acid, itaconic anhydride, itaconic esters and itaconic acid halides, and (B) at least one diamine, preferably wherein the diamine is selected from the group consisting of ethylenediamine, 1,3-diaminopropane, 1,4-diaminobutane, 1,5-pentanediamine, 1,6-diaminohexane, 1,7-diaminoheptane, 1,8-diaminooctane and 1,9-diaminononane, more preferably from ethylenediamine and 1,5-pentanediamine.

5. The method according to claim 3, wherein the pyrrolidone-containing polymer (PP) is obtainable by polymerization of a reaction mixture (rM2), wherein the reaction mixture (rM2) comprises at least the following components: (A) at least one itaconic acid derivative, preferably wherein component (A) is selected from the group consisting of itaconic acid, itaconic anhydride, itaconic esters and itaconic acid halides, and (B) at least one amino acid of the general formula (1) H2N-R 1 -C(=O)-R 2 (1) in R 1 Selected from at least monosubstituted C2-C 20 Alkanediyl and at least monosubstituted C3-C 20 - the group consisting of cycloalkanediyl, wherein the substituent is NH2; R 2 Selected from Cl, Br and OR 3 The group consisting of R 3 Choose from H, C1-C 10 -alkyl, C3-C 10 -cycloalkyl and C2-C 15 -alkenyl, preferably wherein component (B) is selected from the group consisting of L-lysine, D-lysine and a racemic mixture of L-lysine and D-lysine.

6. Use according to any one of claims 1 to 5, wherein the powder coating comprises at least one inorganic pigment, preferably titanium dioxide, and / or at least one organic pigment.

7. The method according to any one of claims 1 to 6, wherein the (to)polymer is an acrylic acid-styrene copolymer and / or Tg calculated using the Fox equation is -60°C to 20°C, preferably -50°C to 10°C, more preferably -30°C to 0°C and / or The average particle size (D 50 value) of the polymer particles measured by dynamic light scattering is from 50 nm to 1000 nm, preferably from 100 nm to 900 nm, more preferably from 150 nm to 750 nm.

8. A powder coating, comprising a) 5 to 30% by weight of at least one pigment; b) 10 to 25 wt. % of at least one redispersible dispersion powder (RDP), the redispersible dispersion powder comprising i) at least one (co)polymer selected from the group consisting of acrylate polymers and acrylic-styrene copolymers, and ii) at least one pyrrolidone-based (co)polymer; c) 40% to 78% by weight of at least one filler; d) 0 to 2 wt. % of at least one dispersant; d) 0% to 2% by weight of at least one thickener; and e) 0% to 2% by weight of at least one defoamer, each based on the total dry weight of the powder coating, wherein the pyrrolidone-based (co)polymer is a pyrrolidone-containing polymer (PP) comprising at least one unit of the general formula (I) to (III) wherein R is independently hydrogen, C1-C4-alkyl, or two groups R are linked to each other to form a six-membered ring; X is -O- or -NR; A is independently selected from C1-C 20 -alkanediyl, C3-C 20 -cycloalkanediyl and C6-C 20 - a group consisting of an arylene group, Wherein the C1-C 20 -alkanediyl is optionally interrupted by one or more non-adjacent oxygen atoms, sulfur atoms or functional groups -NR-, -CO-, -CO-O-, -CO-NR-, -SO- or -SO2-, in which the nitrogen atom is optionally protonated or quaternized, Wherein the C1-C 20 -alkanediyl and the C3-C 20 -cycloalkanediyl optionally carries at least one selected from C(=O)R 2 and SO3H, where R 2 Selected from Cl, Br and OR 3 The group consisting of R 3 Choose from H, C1-C 10 -alkyl, C3-C 10 Cycloalkyl and C2-C 15 -alkenyl group, Wherein the C6-C 20 -arylene is optionally inserted with oxygen, sulfur, -NR-, -SO- or -SO2- and is optionally substituted with -COOH or -SO3H or a mixture of these groups; Z is a group of formula (IV) Where B is C1-C 20 -alkanediyl, C6-C 20 -cycloalkanediyl or a mixture of such groups, wherein the C1-C 20 -alkanediyl optionally interrupted by one or more non-adjacent oxygen atoms, sulfur atoms or functional groups -NR-, -CO-, -CO-O-, -CO-NR-, -SO- or -SO2-, and optionally carrying an additional functional group -COOH or -SO3H, in which the nitrogen atom is optionally protonated or quaternized Alternatively, Z is a mixture of a group of formula (IV) and a group A.

9. The powder coating according to claim 8, comprising a) 8 to 20% by weight of at least one pigment; b) 10 to 19 wt. % of at least one redispersible dispersion powder (RDP), the redispersible dispersion powder comprising i) at least one (co)polymer selected from the group consisting of acrylate polymers and acrylic acid-styrene copolymers, preferably acrylic acid-styrene copolymers, and ii) at least one pyrrolidone-based (co)polymer; c) 55 to 78% by weight of at least one filler; d) 0.2% to 2% by weight of at least one dispersant; d) 0.5% to 2% by weight of at least one thickener; and e) 0.5 to 2% by weight of at least one defoamer, Each is based on the total dry weight of the powder coating.

10. The powder coating according to claim 8, comprising a) 21 to 30% by weight of at least one pigment; b) 15 to 25 wt. % of at least one redispersible dispersion powder (RDP), the redispersible dispersion powder comprising i) at least one (co)polymer selected from the group consisting of acrylate polymers and acrylic acid-styrene copolymers, preferably acrylic acid-styrene copolymers, and ii) at least one pyrrolidone-based (co)polymer; c) 40% to 54% by weight of at least one filler; d) 0.2% to 2% by weight of at least one dispersant; d) 0.5% to 2% by weight of at least one thickener; and e) 0.5 to 2% by weight of at least one defoamer, Each is based on the total dry weight of the powder coating.

11. The powder coating according to any one of claims 8 to 10, wherein the pyrrolidone-containing polymer (PP) is obtainable by polymerization of a reaction mixture (rM1), wherein the reaction mixture (rM1) comprises at least the following components: (A) at least one itaconic acid derivative, preferably wherein component (A) is selected from the group consisting of itaconic acid, itaconic anhydride, itaconic esters and itaconic acid halides, and (B) at least one diamine, preferably wherein the diamine is selected from the group consisting of ethylenediamine, 1,3-diaminopropane, 1,4-diaminobutane, 1,5-pentanediamine, 1,6-diaminohexane, 1,7-diaminoheptane, 1,8-diaminooctane and 1,9-diaminononane, more preferably from ethylenediamine and 1,5-pentanediamine.

12. The powder coating according to any one of claims 8 to 10, wherein the pyrrolidone-containing polymer (PP) is obtainable by polymerization of a reaction mixture (rM2), wherein the reaction mixture (rM2) comprises at least the following components: (A) at least one itaconic acid derivative, preferably wherein component (A) is selected from the group consisting of itaconic acid, itaconic anhydride, itaconic esters and itaconic acid halides, and (B) at least one amino acid of the general formula (1) H2N-R 1 -C(=O)-R 2 (1) in R 1 Selected from at least monosubstituted C2-C 20 -alkanediyl and at least monosubstituted C3-C 20 - the group consisting of cycloalkanediyl, wherein the substituent is NH2; R 2 Selected from Cl, Br and OR 3 The group consisting of R 3 Choose from H, C1-C 10 -alkyl, C3-C 10 -cycloalkyl and C2-C 15 -alkenyl, preferably wherein component (B) is selected from the group consisting of L-lysine, D-lysine and a racemic mixture of L-lysine and D-lysine.

13. A powder coating according to any one of claims 8 to 12, wherein the at least one pigment is an inorganic pigment, preferably selected from the group consisting of titanium dioxide, preferably in rutile form, barium sulfate, zinc oxide, zinc sulfide, basic lead carbonate, antimony trioxide, lithopone (zinc sulfide and barium sulfate), iron oxide, carbon black, graphite, zinc yellow, zinc green, ultramarine, manganese black, antimony black, manganese violet, Prussian blue and Paris green, in particular titanium dioxide; or Organic pigments, preferably wherein the organic pigment is in the form of hollow organic particles and / or based on a polymer comprising nonionic ethylenically unsaturated monomers, preferably wherein the nonionic ethylenically unsaturated monomers are selected from the group consisting of styrene, acrylonitrile, methacrylamide, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate or mixtures thereof.

14. The powder coating according to any one of claims 8 to 13, wherein the at least one filler is selected from the group consisting of calcium carbonate, precipitated calcium carbonate, talc, mica, silica, aluminum silicate, nepheline syenite, clay, calcined clay, feldspar and mixtures thereof.

15. A method for producing a coating, the method comprising mixing a powder coating according to any one of claims 8 to 14 with water, preferably wherein the solid content is adjusted to 45 to 70 wt. %, more preferably 50 to 65 wt. %, based on the total weight of the coating.

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