Aqueous polymer latex of film-forming copolymer suitable as binder in aqueous coating compositions

Abstract

The invention relates to aqueous polymer latices of film-forming copolymers obtainable by aqueous emulsion polymerization of ethylenically unsaturated monomers M comprising 5% to 70% by weight, in particular 10% to 60% by weight, based on the total amount of monomers M, of at least one monomer M1, the cyclopentyl acrylate is selected from cyclopentyl acrylate, cyclopentyl methacrylate and a mixture of cyclopentyl acrylate and cyclopentyl methacrylate; ii. 20% to 90% by weight, in particular 30% to 80% by weight, based on the total amount of monomers M, of at least one monomer M2 selected from the group consisting of C2-C20-alkyl esters of acrylic acid and C5-C20-alkyl esters of methacrylic acid other than tert-butyl acrylate and mixtures thereof; iii. 0% to 40% by weight, in particular 0% to 35% by weight, based on the total amount of monomers M, of one or more monomers M3 selected from the group consisting of tert-butyl acrylate, C1-C4-alkyl esters of methacrylic acid, cyclohexyl methacrylate, isobornyl methacrylate and monovinyl aromatic monomers and mixtures thereof; wherein the total amount of monomers M1 and M3 is in the range of 5% to 70% by weight, in particular at least 10% to 60% by weight, based on the total amount of ethylenically unsaturated monomers M, and wherein the total amount of monomers M1, M2 and M3 is at least 85% by weight, based on the total amount of ethylenically unsaturated monomers M. The invention also relates to a method for producing the aqueous polymer latex of the invention. The method comprises performing an aqueous emulsion polymerization of a monomer M. The invention also relates to the use of these polymer latexes as binders in aqueous coating compositions.

Description

[0001] The present invention relates to an aqueous polymer latex of a film-forming copolymer obtainable by aqueous emulsion polymerization of ethylenically unsaturated monomers M, which ethylenically unsaturated monomers M comprise a combination of (meth)acrylates as monomers. The present invention also relates to a process for producing such polymer latexes and to the use of these polymer latexes as binders in aqueous coating compositions. Furthermore, the present invention relates to an aqueous coating composition comprising a binder polymer in the form of an aqueous polymer latex as defined herein and at least one further component which is conventionally used in aqueous coating compositions and is not a binder.

[0002] Polymer latexes, also known as polymer dispersions, are generally particularly known as binders or binder components for coating compositions, also known as co-binders. As binders or co-binders in coating compositions, one of the important requirements is that they provide hardness and anti-blocking properties to the coating as well as adhesion of the coating to the coated surface. In addition, the polymer latex should provide good opacity, good wet scrub resistance, good soil release properties and low dust accumulation as well as low water absorption.

[0003] Despite progress in many aspects, providing polymer dispersions with balanced application characteristics remains a challenging task, as not only the application characteristics but also the stability of the polymer dispersion must be considered. In particular, it is difficult to reconcile different coating property requirements simultaneously with a binder. Generally, attempts to improve one property of the coating by changing the polymer composition of the binder result in a significant deterioration of other properties of the coating.

[0004] While the polymer dispersions described in the art have particular advantages in one or more respects, they do not always have well-balanced application characteristics. In addition to this, they are based only on monomers prepared from fossil sources. Given the ongoing discussions regarding the impact of CO2 emissions, there is a need to reduce the fossil carbon in polymer latexes. The term bio-based means that the monomers are at least partially prepared from renewable raw materials such as plants, parts of plants, plant waste, biomass, etc. These products are called bio-based and are characterized by having a traceable 14 C carbon content. It is also possible to convert these materials into suitable feeds such as bio-naphtha, as described for example in EP 2 290 045 A1 or EP 2 290 034 A1. Such feeds typically enter a chemical production system such as a steam cracker, in which they are converted along the chemical value chain into products such as acrylic acid, methacrylic acid, acrylates, methacrylates, etc. The content of renewable materials in these products is defined by mass balance methods and can be assigned to these products.

[0005] WO 2014 / 207389 describes the use of 2-octyl acrylate from renewable resources in the production of polymer latexes. The polymer latexes are proposed for use as adhesives. However, a large amount of 2-octyl acrylate in the monomers forming the latex will result in a low glass transition temperature of the resulting polymer, since the homopolymer of 2-octyl acrylate has a glass transition temperature below -40 °C. Thus, latexes with a suitable glass transition temperature will require a substantial amount of conventional fossil-based monomers.

[0006] WO 2018 / 118221 describes copolymer latexes comprising monomers with a high bio-renewable carbon content, the homopolymers of which have a high glass transition temperature, in particular isobornyl methacrylate. However, isobornyl methacrylate can cause problems during emulsion polymerization and can lead to unstable polymer latexes (see, for example, O. Llorente et al. Progress in Organic Coatings 172 (2022) 107137).

[0007] WO 2022 / 018013 describes polymer latexes based on acrylate monomers, methacrylate monomers, and / or monovinyl aromatic monomers, which contain a certain amount of monomers selected from isobutyl acrylate and isopentyl acrylate and mixtures thereof. The coating compositions prepared therefrom produce coatings having improved coating properties such as anti-chalking, water absorption, and flexibility of the coating. Isobutyl acrylate and isopentyl acrylate can be obtained - at least with respect to their alkanol moieties - from biological sources and thus allow for a reduction of fossil carbon in the polymer latex.

[0008] JPH11171927 A describes an aqueous polymer dispersion comprising a polymer based on dicyclopentyl (meth)acrylate. This polymer has a number average molecular weight of 1000 to 1,000,000 and exhibits low odor and high heat resistance.

[0009] However, there is still a need to provide polymer latexes that are at least partially based on bio-based monomers and have acceptable or improved application characteristics that make them suitable as adhesives in aqueous coating compositions, especially for external and internal application.

[0010] Surprisingly, it has been found that polymer latexes based on a combination of a certain amount of monomer M1 selected from cyclopentyl acrylate and cyclopentyl methacrylate and other conventional or bio-based monomers M2 as defined herein improve the coating properties of coating compositions, in particular the coating properties of coating compositions, namely gloss, thickening efficiency, spreading rate (opacity), adhesion to the coated surface, in particular the adhesion of the coating to a surface previously coated with an alkyd resin (alkyd adhesion). In addition, monomer M1 can - at least with respect to its alkanol moiety - be obtained from biological sources and thus allows for a reduction in fossil carbon in the polymer latex.

[0011] Accordingly, the present invention relates to an aqueous polymer latex of a film-forming copolymer obtainable by aqueous emulsion polymerization of ethylenically unsaturated monomers M, said ethylenically unsaturated monomers M comprising

[0012] i. at least one monomer M1 in an amount of 5% to 70% by weight, in particular 10% to 60% by weight, based on the total amount of monomers M, selected from cyclopentyl acrylate, cyclopentyl methacrylate and mixtures thereof;

[0013] ii. at least one monomer M2 in an amount of 20% to 90% by weight, in particular 30% to 80% by weight, based on the total amount of monomers M, selected from C2-C 20 -alkyl esters of acrylic acid and C5-C 20 -alkyl esters of methacrylic acid and mixtures thereof, excluding tert-butyl acrylate;

[0014] iii. one or more monomers M3 in an amount of 0% to 40% by weight, in particular 0% to 35% by weight, based on the total amount of monomers M, selected from tert-butyl acrylate, C1-C4-alkyl esters of methacrylic acid, cyclohexyl methacrylate, isobornyl methacrylate and monovinyl aromatic monomers and mixtures thereof;

[0015] wherein the total amount of monomers M1 and M3 is in the range of 5% to 70% by weight, in particular 10% to 60% by weight, based on the total amount of ethylenically unsaturated monomers M, and wherein the total amount of monomers M1, M2 and M3 is at least 85% by weight based on the total amount of ethylenically unsaturated monomers M.

[0016] The present invention also relates to a method for producing the aqueous polymer latex of the present invention. The method comprises carrying out an aqueous emulsion polymerization of monomers M.

[0017] The present invention also relates to the use of these polymer latexes as binders in aqueous coating compositions.

[0018] Furthermore, the present invention relates to an aqueous coating composition comprising

[0019] a) An adhesive polymer in the form of an aqueous polymer latex as defined herein; and

[0020] b) At least one additional component which is conventionally used in aqueous coating compositions and is not an adhesive.

[0021] The present invention is associated with several benefits.

[0022] - The polymer latex is stable and provides good and well - balanced application characteristics for aqueous coating compositions, such as improved thickening efficiency, improved adhesion characteristics such as high dry alkyd adhesion, improved spreading rate (opacity), high anti - blocking property, good soil - release property, good wet scrub resistance, and low dust accumulation.

[0023] - Since the polymer latex contains a significant amount of monomers M1, M2, and M3, at least with respect to monomer M1 and also some of monomers M2 and M3, which can be obtained from bio - renewable sources, they allow a significant reduction in the need for fossil carbon, in particular a reduction of at least 10%, especially at least 25% or even at least 40%, for example 55%, and up to 100%. The incorporation of bio - carbon and the reduction of fossil carbon can reduce the carbon footprint of the polymer latex.

[0024] Due to their well - balanced application characteristics, the polymer latex can be particularly used as an adhesive in aqueous architectural coatings and has beneficial properties in both aqueous primer and aqueous top - coat formulations, as well as in exterior and interior architectural paints.

[0025] Herein and throughout the specification, the term "bio - based monomer" means that the corresponding monomer is at least partially produced from molecules obtained from bio - renewable resources such as biomass. Such molecules are characterized by a bio - carbon content of at least 90 mol - %, preferably at least 95 mol - %, for example 100 mol - %, based on the total amount of carbon atoms in cyclopentanol.

[0026] The term "bio - carbon" indicates that the carbon is of biological origin and comes from biological materials / renewable resources. Herein and hereinafter, renewable sources and bio - renewable sources are used synonymously and refer to sources of biological origin other than fossil sources. The content of bio - carbon and the content of biological materials are expressions indicating the same value. Materials from renewable sources or biological materials are organic materials in which the carbon comes from CO2 that has been recently (on a human scale) fixed by photosynthesis from the atmosphere. The isotope ratio of biological materials (100% natural - source carbon) 14 C / 12 C is greater than 10 -12 Typically about 1.2×10 -12 while the isotope ratio of fossil materials is zero. In fact, the isotope 14C is formed in the atmosphere and then incorporated via photosynthesis on a time scale of up to several decades. 14 C has a half-life of 5,730 years. Thus, materials from photosynthesis, i.e., typically plants, necessarily have the maximum content of 14 isotopic C. The determination of the content of biological materials or biochar can be carried out according to Standard ASTM D6866-12, Method B (ASTM D 6866-06), and ASTM D 7026 (ASTM D 7026-04).

[0027] Herein and throughout the specification, the term “(meth)acryloyl” includes both acryloyl and methacryloyl. Thus, the term “(meth)acrylate” includes acrylate and methacrylate, and the term “(meth)acrylamide” includes acrylamide and methacrylamide.

[0028] Herein and throughout the specification, the term “aqueous coating composition” means a liquid aqueous coating composition containing an amount of water sufficient to achieve fluidity as the continuous phase.

[0029] Herein and throughout the specification, the terms “wt.-%” and “% by weight (% b.w.)” are used synonymously.

[0030] Herein and throughout the specification, the term “pphm” means parts per 100 monomers, i.e., parts by weight per 100 parts of monomers, and corresponds to the relative amount of a substance based on the total amount of monomer M in % by weight.

[0031] Herein and throughout the specification, the term “ethylenically unsaturated monomer” should be understood as a monomer having at least one C═C double bond, e.g., 1, 2, 3, or 4 C═C double bonds, which double bonds are free-radically polymerizable, i.e., which polymerize under the conditions of an aqueous free-radical emulsion polymerization process to obtain a polymer having a carbon atom backbone. Herein and throughout the specification, the term “monoethylenically unsaturated” should be understood as a monomer having a single C═C double bond that is prone to free-radical polymerization under the conditions of an aqueous free-radical emulsion polymerization.

[0032] Herein and throughout the specification, the terms “ethoxylated” and “polyethoxylated” are used synonymously and refer to a compound having an oligomeric or polyoxyethylene group formed by repeating units O—CH2CH2. In this context, the term “degree of ethoxylation” refers to the number average of the repeating units O—CH2CH2 in these compounds.

[0033] Herein and throughout the specification, in the context of compounds, especially monomers, the term “nonionic” means that the corresponding compound does not carry any ionic functional groups or any functional groups that can be converted into ionic groups by protonation or deprotonation.

[0034] Herein and throughout the specification, the prefix C used in connection with a compound or molecular moiety n -C m each indicates the range of possible numbers of carbon atoms that a molecular moiety or compound may have. The term "C1-C n alkyl" denotes a group of straight-chain or branched-chain saturated hydrocarbon groups having from 1 to n carbon atoms. The term "C n / C m alkyl" denotes a mixture of two alkyl groups, one having n carbon atoms and the other having m carbon atoms.

[0035] For example, the term C1-C 20 alkyl denotes a group of straight-chain or branched-chain saturated hydrocarbon groups having from 1 to 20 carbon atoms, while the term C1-C4 alkyl denotes a group of straight-chain or branched-chain saturated hydrocarbon groups having from 1 to 4 carbon atoms, and C5-C 20 alkyl denotes a group of straight-chain or branched-chain saturated hydrocarbon groups having from 5 to 20 carbon atoms. Examples of alkyl groups include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, 2-methylpropyl (isopropyl), 1,1-dimethylethyl (tert-butyl), pentyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 2,2-dimethylpropyl, 1-ethylpropyl, 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, 1-ethyl-2-methylpropyl, n-heptyl, 2-heptyl, n-octyl, 2-octyl, 2-ethylhexyl, nonyl, isononyl, decyl, undecyl, dodecyl, tridecyl, isotridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, eicosyl, heneicosyl, docosyl, and in the case of nonyl, isononyl, decyl, undecyl, dodecyl, tridecyl, isotridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, eicosyl, heneicosyl, docosyl, their isomers, especially mixtures of isomers, such as "isononyl", "isodecyl". Examples of C1-C4-alkyl are, for example, methyl, ethyl, propyl, 1-methylethyl, butyl, 1-methylpropyl, 2-methylpropyl or 1,1-dimethylethyl.

[0036] As used herein, the term "cyclopentyl" refers to a monocyclic cycloaliphatic group having 5 carbon atoms, which is unsubstituted or substituted with 1, 2, 3 or 4 methyl groups.

[0037] As used herein, the term "cyclohexyl" refers to a monocyclic cycloaliphatic group having 6 carbon atoms, which is unsubstituted or substituted with 1, 2, 3 or 4 methyl groups.

[0038] The term "isobornyl" refers to 1,7,7-trimethylbicyclo[2.2.1]heptyl.

[0039] According to the present invention, the monomer M comprises at least one monomer M1 selected from cyclopentyl acrylate, cyclopentyl methacrylate and mixtures thereof.

[0040] In a specific group of embodiments, the monomer M1 comprises at least 50% by weight, particularly at least 80% by weight, especially at least 90% by weight, based on the total amount of the monomer M1, of cyclopentyl methacrylate. In particular, the monomer M1 is cyclopentyl methacrylate.

[0041] In yet another specific group of embodiments, the monomer M1 is a mixture comprising at least 50% by weight, particularly at least 80% by weight, especially at least 90% by weight, based on the total amount of the monomer M1, of cyclopentyl acrylate and cyclopentyl methacrylate. In this specific group of embodiments, the monomer molar ratio of cyclopentyl acrylate to cyclopentyl methacrylate is particularly in the range of 1:1 to 10:1.

[0042] Cyclopentyl acrylate and cyclopentyl methacrylate are typically produced respectively by the esterification of acrylic acid or methacrylic acid with cyclopentanol, or respectively by the transesterification of methyl (meth)acrylate or ethyl (meth)acrylate with cyclopentanol. (Meth)acrylic acid cyclopentyl ester can - at least with respect to its alkanol moiety - be obtained from biological sources and thus allows for a reduction of fossil carbon in the polymer latex.

[0043] Cyclopentanol can be produced from furfural via catalytic hydrogenation as described in Journal of Energy Chemistry 23 (2014) 91 - 96. Furfural is obtained, for example, from biomass. Such cyclopentanol has a bio - carbon content of approximately 100 mol - %, and thus allows for the production of cyclopentyl methacrylate and cyclopentyl acrylate having a bio - carbon content of at least 55 mol - % and at least 62 mol - %, respectively.

[0044] Acrylic acid and / or methacrylic acid for the esterification can be obtained from fossil sources according to standard procedures. Acrylic acid can also be prepared from renewable raw materials, for example according to WO 2006 / 092272 or DE 10 2006 039 203 A or EP 2 922580.

[0045] Preferably, at least a portion of the isolate used to synthesize M1 is derived from bio-renewable raw materials. Accordingly, specific embodiments of the present invention relate to a polymer latex as defined herein, wherein at least the carbon atoms of the cyclopentyl group in monomer M1 are of biological origin, i.e., they are at least partially made of biological carbon. In particular, the cyclopentanol used to produce monomer M1 preferably has a biological carbon content of at least 90 mol-% based on the total amount of carbon atoms in the cyclopentanol. This content is advantageously higher, particularly greater than or equal to 95 mol-%, preferably greater than or equal to 98 mol-% and advantageously equal to 100 mol-%. Similarly, acrylic acid and / or methacrylic acid can be produced from renewable materials. However, to date, acrylic acid and / or methacrylic acid produced from biological materials are not available on a large scale. Accordingly, monomer M1 has a biological carbon content of preferably at least 51 mol-%, particularly at least 55 mol-%, based on the total amount of carbon atoms in cyclopentyl acrylate and cyclopentyl methacrylate, respectively. By using monomer M1 that is at least partially of biological origin, the demand for fossil carbon in the polymer latex can be significantly reduced. In particular, an amount of carbon of biological origin of at least 10 mol-%, particularly at least 15 mol-% or at least 20 mol-% or higher, such as at least 30 mol-% or at least 40 mol-% or at least 50 mol-% or higher, can be achieved.

[0046] The total amount of monomer M1 is from 5% to 70% by weight, particularly from 10% to 60% by weight or from 15% to 60% by weight, especially from 20% to 50% by weight, based on the total weight of monomer M.

[0047] In addition to monomer M1, monomer M of the polymer forming the latex may comprise one or more monomers M2 as defined above.

[0048] Suitable monomers M2 are selected from the group consisting of:

[0049] - C2-C 20 - alkyl esters of acrylic acid other than tert-butyl acrylate, including but not limited to ethyl acrylate, n-propyl acrylate, n-butyl acrylate, isobutyl acrylate, n-pentyl acrylate, 2-methylbutyl acrylate, isopentyl acrylate, n-hexyl acrylate, n-octyl acrylate, 2-octyl acrylate, 2-ethylhexyl acrylate, n-decyl acrylate, isodecyl acrylate, 2-propylheptyl acrylate, lauryl acrylate, C 12 / C 14 - alkyl esters, C 12 - C 15 - alkyl esters, isotridecyl acrylate, C 17 - alkyl esters, C 16 / C18 - alkyl esters and stearyl acrylate;

[0050] - C5-C 20 - alkyl esters of methacrylic acid, including but not limited to n-butyl methacrylate, n-pentyl methacrylate, n-hexyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate, n-decyl methacrylate, 2-propylheptyl methacrylate, lauryl methacrylate, C 12 / C 14 - alkyl esters, C 12 - C 15 - alkyl esters, isotridecyl methacrylate, C 16 / C 18 - alkyl esters and stearyl methacrylate; and

[0051] - mixtures thereof.

[0052] Preferred monomer M2 is selected from the group consisting of ethyl acrylate, n-propyl acrylate, n-butyl acrylate, isobutyl acrylate, n-pentyl acrylate, 2-methylbutyl acrylate, isopentyl acrylate, n-hexyl acrylate, n-octyl acrylate, 2-octyl acrylate, 2-ethylhexyl acrylate, 2-propylheptyl acrylate and mixtures thereof. Preferably, monomer M2 comprises at least one of n-butyl acrylate, 2-ethylhexyl acrylate, 2-octyl acrylate, isopentyl acrylate (= 3-methylbutyl acrylate), 2-methylbutyl acrylate and isobutyl acrylate or mixtures thereof. Isopentyl acrylate, 2-methylbutyl acrylate or isobutyl acrylate can be produced from fossil sources or can be at least partially biobased. In particular, the isopentyl, 2-methylbutyl and isobutyl moieties of isopentyl acrylate, 2-methylbutyl acrylate and isobutyl acrylate are biobased, i.e., the monomers are obtained by esterification of acrylic acid (which can be biobased or of fossil origin) with biobased isopentanol, 2-methylbutanol or isobutanol, respectively. Similarly, the 2-octanol moiety of 2-octyl acrylate can be biobased, i.e., the monomer is obtained by esterification of acrylic acid (which can be biobased or of fossil origin) with biobased 2-octanol.

[0053] In a preferred group of embodiments, monomer M2 comprises isobutyl acrylate, especially biobased isobutyl acrylate. In particular, the monomer is isobutyl acrylate, especially biobased isobutyl acrylate. In this preferred group of embodiments, monomer M2 can also be a mixture of isobutyl acrylate and at least one other C2-C 10 alkyl acrylate such as n-butyl acrylate, isopentyl acrylate, 2-methylbutyl acrylate, 2-octyl acrylate and 2-ethylhexyl acrylate.

[0054] In the context of this group of embodiments, it is preferred that the amount of isobutyl acrylate is in the range of 20% to 80% by weight, in particular 25% to 75% by weight, especially 30% to 70% by weight, based on the total amount of monomer M.

[0055] In another preferred group of embodiments, monomer M2 comprises n-butyl acrylate. In this group of embodiments, n-butyl acrylate can be the sole monomer or a mixture of n-butyl acrylate and at least one further C2-C 10 alkyl acrylate such as isoamyl acrylate, 2-methylbutyl acrylate, 2-octyl acrylate and 2-ethylhexyl acrylate.

[0056] In the context of this group of embodiments, it is preferred that the amount of n-butyl acrylate is in the range of 20% to 80% by weight, in particular 25% to 75% by weight, especially 30% to 70% by weight, based on the total amount of monomer M.

[0057] Isobutyl acrylate, 2-methylbutyl acrylate, isoamyl acrylate and 2-octyl acrylate are typically produced respectively by the esterification of acrylic acid with isobutanol (2-methylpropan-1-ol), 2-methylbutanol, isoamyl alcohol (3-methylbutan-1-ol) or 2-octanol, or respectively by the transesterification of methyl acrylate or ethyl acrylate with isobutanol (2-methylpropan-1-ol), 2-methylbutan-1-ol, isoamyl alcohol (3-methylbutan-1-ol) or 2-octanol.

[0058] Isobutanol, 2-methylbutanol, and isopentanol, as well as mixtures thereof, can be produced on a large scale by fermentation from a variety of renewable raw materials, including corn, wheat, sorghum, barley, and sugarcane, particularly from cellulosic raw materials and thus from biological or renewable sources. In particular, fermentation can produce a mixture containing different alkanols, and isobutanol, 2-methylbutan-1-ol, and 3-methylbutan-1-ol can be separated from this mixture by conventional techniques such as fractional distillation. Thereby, pure alcohols (purity > 90%) can be obtained, or mixtures containing at least two alcohols selected from the group consisting of isobutanol, 2-methylbutan-1-ol, and 3-methylbutan-1-ol and having a total amount of at least 80%, particularly at least 90%, can be obtained. For example, a mixture containing at least 80% by weight of 2-methylbutanol and 3-methylbutanol and up to 20% by weight of isobutanol can be used for esterification or transesterification. In this mixture, the molar ratio of 3-methylbutanol to 2-methylbutan-1-ol can vary, for example, from 1:10 to 10:1, and particularly in the range of 1:1 to 10:1. 2-Octanol can be produced by base-catalyzed thermal cleavage of ricinoleic acid, with sebacic acid as a by-product. Castor oil, which consists mainly of ricinoleic acid, is the main raw material. Therefore, incorporating these monomers M2 into the polymer latex significantly increases the amount of bio-carbon in the polymer latex. The incorporation of bio-carbon and the reduction of fossil carbon can reduce the carbon footprint of the polymer latex.

[0059] Thus, specific embodiments of the present invention relate to a polymer latex as defined herein, wherein the carbon atoms of at least isobutyl, 2-methylbutyl, isoamyl and 2-octyl in monomer M2, in particular the carbon atoms of at least isobutyl in monomer M2, are of biological origin, i.e., they are at least partially made of biological carbon. In particular, isobutanol, 2-methylbutan-1-ol, 3-methylbutanol and 2-octanol used to produce monomer M2 preferably have a biological carbon content of at least 90 mol-% based on the total amount of carbon atoms in isobutanol, 2-methylpentanol, 3-methylbutanol and 2-octanol, respectively. This content is advantageously higher, especially greater than or equal to 95 mol-%, preferably greater than or equal to 98 mol-% and advantageously equal to 100 mol-%. Similarly, acrylic acid can be produced from renewable materials. However, so far, acrylic acid produced from biological materials is not available on a large scale. Therefore, monomer M2 preferably has a biological carbon content of at least 51 mol-%, in particular at least 54 mol-% and especially at least 57 mol-% based on the total amount of carbon atoms in isobutyl acrylate, 2-methylbutyl acrylate, isoamyl acrylate and 2-octyl acrylate, respectively. By using monomer M2 that is at least partially of biological origin, the demand for fossil carbon in the polymer latex can be significantly reduced. In particular, an amount of carbon of biological origin of at least 10 mol-%, especially at least 15 mol-% or at least 20 mol-% or higher, such as 30 mol-% or 40 mol-% or higher, can be achieved.

[0060] The total amount of monomer M2 is 20% to 90% by weight, in particular 30% to 80% by weight or 30% to 70% by weight, especially 40% to 65% by weight, based on the total weight of monomer M.

[0061] In addition to monomers M1 and M2, monomer M of the polymer forming the latex may comprise one or more monomers M3 as defined above.

[0062] Suitable monomers M3 are selected from the group consisting of:

[0063] - C1-C4-alkyl esters of methacrylic acid, such as methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, sec-butyl methacrylate, isobutyl methacrylate and tert-butyl methacrylate;

[0064] - tert-butyl acrylate;

[0065] - cyclohexyl methacrylate, isobornyl methacrylate;

[0066] - monovinyl aromatic monomers, such as styrene, 2-methylstyrene, 4-methylstyrene; and

[0067] - its mixture.

[0068] In a preferred group of embodiments, monomer M3 is selected from the group consisting of:

[0069] - C1-C4-alkyl esters of methacrylic acid, especially methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isobutyl methacrylate and tert-butyl methacrylate;

[0070] - tert-butyl acrylate;

[0071] - cyclohexyl methacrylate, isobornyl methacrylate;

[0072] - styrene; and

[0073] - its mixture.

[0074] In this group, monomer M3 is particularly selected from the group consisting of:

[0075] - methyl methacrylate, n-butyl methacrylate;

[0076] - tert-butyl acrylate;

[0077] - cyclohexyl methacrylate, isobornyl methacrylate;

[0078] - styrene; and

[0079] - its mixture.

[0080] In a specific group of embodiments (M3-A), monomer M3 contains at least 50% by weight, especially at least 80% by weight or 100% by weight, based on the total amount of monomer M3 in monomer M, of methyl methacrylate. In this group, more particularly, monomer M3 is selected from the group consisting of methyl methacrylate and combinations of methyl methacrylate with n-butyl methacrylate, tert-butyl acrylate, cyclohexyl methacrylate, isobornyl methacrylate or with styrene.

[0081] In this specific group of embodiments M3-A, preferably monomer M3 is methyl methacrylate.

[0082] In the context of group of embodiments M3-A, preferably, the amount of methyl methacrylate is in the range of 1% to 40% by weight, especially 1.5% to 35% by weight, particularly 2% to 30% by weight, based on the total amount of monomer M.

[0083] In another specific group of embodiments (M3-B), monomer M3 comprises styrene in an amount of at least 50% by weight, in particular at least 80% by weight or 100% by weight, based on the total amount of monomer M3 in monomer M. In this group, more particularly, monomer M3 is selected from the group consisting of styrene and combinations of styrene with methyl methacrylate, n-butyl methacrylate, tert-butyl acrylate, cyclohexyl methacrylate or isobornyl methacrylate.

[0084] In this specific group of embodiments M3-A, preferably monomer M3 is methyl methacrylate.

[0085] In the context of group of embodiments M3-B, preferably, the amount of styrene is in the range of 1% to 30% by weight, in particular 1.5% to 25% by weight, especially 2% to 20% by weight, based on the total amount of monomer M.

[0086] The total amount of monomer M3 is 0% to 40% by weight, in particular 0% to 35% by weight or 1% to 35% by weight, based on the total weight of monomer M.

[0087] The total amount of monomers M1 and M3 is preferably in the range of 5% to 70% by weight, in particular in the range of 10% to 65% by weight, especially in the range of 15% to 60% by weight, based on the total amount of ethylenically unsaturated monomer M.

[0088] The total amount of monomers M1, M2 and M3 is at least 85% by weight, in particular at least 90% by weight, especially at least 95% by weight, based on the total amount of ethylenically unsaturated monomer M.

[0089] The weight ratio of M1 to M2 is generally in the range of 1:10 to 10:1, in particular in the range of 1:5 to 5:1, preferably in the range of 1:4 to 4:1, especially in the range of 1:3 to 3:1.

[0090] If M3 is present, the weight ratio of M1 to M3 is generally in the range of 1:5 to 30:1, in particular in the range of 1:4 to 25:1, preferably in the range of 1:2 to 20:1.

[0091] Monomer M may further comprise at least one monomer M4 selected from monoethylenically unsaturated monomers having acidic groups.

[0092] Suitable monomers M4 include but are not limited to

[0093] - monoethylenically unsaturated monocarboxylic acids having 3 to 6 carbon atoms, such as acrylic acid, methacrylic acid, crotonic acid, 2-ethylacrylic acid, 2-propylacrylic acid, 2-acryloyloxyacetic acid and 2-methacryloyloxyacetic acid;

[0094] - Monoethylenically unsaturated dicarboxylic acids having 4 to 6 carbon atoms, such as itaconic acid, citraconic acid, and fumaric acid;

[0095] - Half-esters of monoethylenically unsaturated dicarboxylic acids having 4 to 6 carbon atoms with C1-C4 alkanols such as methanol or ethanol, such as half-esters of itaconic acid, citraconic acid, maleic acid, or fumaric acid with methanol or ethanol;

[0096] - Monoethylenically unsaturated sulfonic acids, such as vinylsulfonic acid, allylsulfonic acid, styrenesulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid,

[0097] - Monoethylenically unsaturated phosphonic acids, such as vinylphosphonic acid, allylphosphonic acid, styrenephosphonic acid, and 2-acrylamido-2-methylpropanephosphonic acid,

[0098] - Monoethylenically unsaturated phosphoric acids, such as monophosphoric esters of hydroxyalkyl acrylates, monophosphoric esters of hydroxyalkyl methacrylates, monophosphoric esters of alkoxylated hydroxyalkyl acrylates, and monophosphoric esters of alkoxylated hydroxyalkyl methacrylates, in particular monophosphoric esters of 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, or 2-hydroxybutyl acrylate, monophosphoric esters of 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, or 2-hydroxybutyl methacrylate, monophosphoric esters of ethoxylated hydroxy-C2-C4 alkyl acrylates, monophosphoric esters of propoxylated hydroxy-C2-C4 alkyl acrylates, monophosphoric esters of ethoxylated hydroxy-C2-C4 alkyl methacrylates, and monophosphoric esters of propoxylated hydroxy-C2-C4 alkyl methacrylates.

[0099] The above monomer M4 can exist in its acidic form or in the form of its salts, in particular in the form of its alkali metal salts or ammonium salts.

[0100] Among the above monomers M4, preferred are monoethylenically unsaturated monocarboxylic acids, monoethylenically unsaturated dicarboxylic acids, and monoethylenically unsaturated sulfonic acids and their salts, especially alkali metal salts and ammonium salts. Particularly preferred are acrylic acid, methacrylic acid, itaconic acid, 2-acrylamido-2-methylpropanesulfonic acid and their salts, especially alkali metal salts and ammonium salts, and combinations thereof. More preferred are monoethylenically unsaturated monocarboxylic acids and monoethylenically unsaturated sulfonic acids and their salts, especially alkali metal salts and ammonium salts, especially acrylic acid, methacrylic acid, 2-acrylamido-2-methylpropanesulfonic acid, its salts, especially alkali metal salts and ammonium salts, and mixtures of the above monomers. In a specific group of embodiments, monomer M4 contains methacrylic acid. In particular, monomer M4 is methacrylic acid or a mixture of acrylic acid and methacrylic acid. In another specific group of embodiments, monomer M4 contains acrylic acid. In another specific group of embodiments, monomer M4 contains 2-acrylamido-2-methylpropanesulfonic acid or its salt, especially an alkali metal salt or an ammonium salt. In particular, monomer M4 is 2-acrylamido-2-methylpropanesulfonic acid or its salt, especially an alkali metal salt or an ammonium salt, or a mixture of acrylic acid and 2-acrylamido-2-methylpropanesulfonic acid or its salt, especially an alkali metal salt or an ammonium salt.

[0101] The total amount of monomer M4 is 0.05% to 5% by weight or 0.1% to 4% by weight, especially 0.05% to 3.5% by weight or 0.1% to 3% by weight, particularly 0.2% to 3% by weight or 0.5% to 3% by weight or 0.5% to 2% by weight, based on the total weight of monomer M.

[0102] Monomer M may further comprise at least one monoethylenically unsaturated nonionic monomer M5 which has a solubility of at least 60 g / L in deionized water at 20 °C and 1 bar.

[0103] Suitable monomers M5 are selected from the group consisting of nonionic monoethylenically unsaturated monomers having functional groups selected from the group consisting of: hydroxyalkyl, especially hydroxy-C2-C4-alkyl, primary formamide groups, urea groups, keto groups and combinations thereof.

[0104] The total amount of monomer M5 will generally not exceed 10% by weight, especially 7% by weight, based on the total amount of monomer M. In particular, if present, the total amount of monomer M5 is generally 0% to 9.95% by weight, 0.05% to 9.95% by weight, especially 0.1% to 7% by weight, particularly 0.1% to 5% by weight or 0.1% to 4% by weight or 0.5% to 3% by weight or 1% to 3% by weight, based on the total weight of monomer M.

[0105] Examples of monomer M5 having a formamide group (monomer M5a hereinafter) include, but are not limited to, primary amides of monoethylenically unsaturated monocarboxylic acids having 3 to 6 carbon atoms, such as acrylamide and methacrylamide, and C1-C4-alkyl amides of monoethylenically unsaturated monocarboxylic acids having 3 to 6 carbon atoms, such as N-methylacrylamide, N-ethylacrylamide, N-propylacrylamide, N-isopropylacrylamide, N-butylacrylamide, N-methylmethacrylamide, N-ethylmethacrylamide, N-propylmethacrylamide, N-isopropylmethacrylamide and N-butylmethacrylamide. Most preferably, monomer M5a is selected from acrylamide and methacrylamide.

[0106] Examples of monomer M5 having a urea group (monomer M5b hereinafter) are C1-C4-alkyl esters of acrylic or methacrylic acid and N-C1-C4-alkyl amides of acrylic or methacrylic acid, wherein the C1-C4-alkyl bears a urea group or a 2-oxoimidazoline group, such as 2-(2-oxo-imidazolidin-1-yl)ethyl acrylate, 2-(2-oxo-imidazolidin-1-yl)ethyl methacrylate (which are also referred to as 2-ureidoethyl acrylate and 2-ureidoethyl methacrylate, respectively), N-(2-acryloyloxyethyl)urea, N-(2-methacryloyloxyethyl)urea, N-(2-(2-oxo-imidazolidin-1-yl)ethyl)acrylamide, N-(-2-(2-oxo-imidazolidin-1-yl)ethyl)methacrylamide, and allyl- or vinyl-substituted ureas and allyl- or vinyl-substituted 2-oxoimidazoline compounds, such as 1-allyl-2-oxoimidazoline, N-allylurea and N-vinylurea.

[0107] Examples of monomer M5 having a keto group (monomer M5c hereinafter) are

[0108] - C2-C8-oxoalkyl esters of acrylic or methacrylic acid and N-C2-C8-oxoalkyl amides of acrylic or methacrylic acid, such as diacetoneacrylamide (DAAM) and diacetonemethacrylamide, and

[0109] - C1-C4-alkyl esters of acrylic or methacrylic acid and N-C1-C4-alkyl amides of acrylic or methacrylic acid, wherein the C1-C4-alkyl bears a 2-acetylacetoxy group having the formula O-C(=O)-CH2-C(=O)-CH3 (also referred to as acetoacetoxy), such as acetoacetoxyethyl acrylate, acetoacetoxypropyl methacrylate, acetoacetoxybutyl methacrylate and 2-(acetoacetoxy)ethyl methacrylate.

[0110] Preferably, monomer M comprises or consists of the following:

[0111] i. Cyclopentyl methacrylate as monomer M1 in an amount of 5% to 70% by weight, in particular 10% to 65% by weight or 15% to 60% by weight, especially 20% to 50% by weight, based on the total amount of monomers M;

[0112] ii. At least one monomer M2 in an amount of 20% to 90% by weight, in particular 30% to 80% by weight or 30% to 70% by weight, especially 40% to 65% by weight, based on the total amount of monomers M, which comprises isobutyl acrylate or is isobutyl acrylate;

[0113] iii. At least one monomer M3 in an amount of 0% to 40% by weight, in particular 0% to 35% by weight or 1% to 35% by weight, based on the total amount of monomers M, which comprises methyl methacrylate, styrene or a combination thereof or is selected from the group consisting of methyl methacrylate, styrene or a combination thereof;

[0114] iv. One or more monoethylenically unsaturated monomers M4 in an amount of 0.05% to 5% by weight, or 0.1% to 4% by weight, in particular 0.05% to 3.5% by weight or 0.1% to 3% by weight, especially 0.2% to 3% by weight or 0.5% to 3% by weight, or 0.5% to 2% by weight, based on the total amount of monomers M, which are selected from monoethylenically unsaturated monomers having acidic groups;

[0115] v. If present, one or more nonionic monomers M5 in an amount of 0% to 9.95% by weight, 0.05% to 9.95% by weight, in particular 0.1% to 7% by weight, especially 0.1% to 5% by weight or 0.1% to 4% by weight or 0.5% to 3% by weight or 1% to 3% by weight, based on the total weight of monomers M, which have a solubility of at least 60 g / L in deionized water at 20 °C and 1 bar,

[0116] or

[0117] i. Cyclopentyl methacrylate as monomer M1 in an amount of 5% to 70% by weight, in particular 10% to 65% by weight or 15% to 60% by weight, especially 20% to 50% by weight, based on the total amount of monomers M;

[0118] ii. At least one monomer M2 in an amount of 20% to 90% by weight, in particular 30% to 80% by weight or 30% to 70% by weight, especially 40% to 65% by weight, based on the total amount of monomers M, which comprises n-butyl acrylate or is n-butyl acrylate;

[0119] iii. At least one monomer M3, based on 0% to 40% by weight, especially 0% to 35% by weight or 1% to 35% by weight of the total amount of monomer M, which comprises methyl methacrylate, styrene or a combination thereof or is selected from the group consisting of methyl methacrylate, styrene or a combination thereof;

[0120] iv. One or more monoethylenically unsaturated monomers M4, based on 0.05% to 5% by weight, or 0.1% to 4% by weight, especially 0.05% to 3.5% by weight or 0.1% to 3% by weight, particularly 0.2% to 3% by weight or 0.5% to 3% by weight, or 0.5% to 2% by weight of the total amount of monomer M, which are selected from monoethylenically unsaturated monomers having acidic groups;

[0121] v. If present, one or more nonionic monomers M5, based on 0% to 9.95% by weight, 0.05% to 9.95% by weight, especially 0.1% to 7% by weight, particularly 0.1% to 5% by weight or 0.1% to 4% by weight or 0.5% to 3% by weight or 1% to 3% by weight of the total weight of monomer M, which have a solubility of at least 60 g / L in deionized water at 20 °C and 1 bar,

[0122] wherein the total amount of monomers M1 and M3 is in the range of 5% to 70% by weight, especially in the range of 10% to 65% by weight, particularly in the range of 15% to 60% by weight, based on the total amount of ethylenically unsaturated monomer M, and wherein the total amount of monomers M1, M2 and M3 is at least 85% by weight, especially at least 90% by weight, particularly at least 95% by weight, based on the total amount of ethylenically unsaturated monomer M.

[0123] In group 1 of the specific embodiments, monomer M comprises the following items or consists of the following items:

[0124] i. Cyclopentyl methacrylate as monomer M1, based on 15% to 69.95% by weight, especially 20% to 64.8% by weight, particularly 25% to 59.4% by weight of the total amount of monomer M;

[0125] ii. Isobutyl acrylate as monomer M2, based on 30% to 84.95% by weight, especially 35% to 79.8% by weight, particularly 40% to 74.4% by weight of the total amount of monomer M;

[0126] iii. One or more monoethylenically unsaturated monomers M4, based on 0.05% to 5% by weight, especially 0.1% to 4% by weight, particularly 0.5% to 3% by weight of the total amount of monomer M, which are selected from monoethylenically unsaturated monomers having acidic groups;

[0127] iv. one or more non-ionic monomers M5 in an amount of 0% to 9.95% by weight, especially 0.05% to 5% by weight, particularly 0.1% to 4% by weight, based on the total weight of monomer M, which have a solubility of at least 60 g / L in deionized water at 20 °C and 1 bar,

[0128] wherein the total amount of monomers M1 and M2 is at least 85% by weight, especially at least 90% by weight, particularly at least 95% by weight, based on the total weight of the ethylenically unsaturated monomers M;

[0129] or

[0130] i. cyclopentyl methacrylate as monomer M1 in an amount of 10% to 68.95% by weight, especially 15% to 63.4% by weight, particularly 15% to 57.4% by weight, based on the total weight of monomer M;

[0131] ii. isobutyl acrylate as monomer M2 in an amount of 30% to 70% by weight, especially 35% to 65% by weight, particularly 40% to 60% by weight, based on the total weight of monomer M;

[0132] iii. monomer M3 in an amount of 1% to 35% by weight, especially 1.5% to 30% by weight, particularly 2% to 25% by weight, based on the total weight of monomer M, which is selected from methyl methacrylate, styrene and combinations thereof;

[0133] iv. one or more monoethylenically unsaturated monomers M4 in an amount of 0.05% to 5% by weight, especially 0.1% to 4% by weight, particularly 0.5% to 3% by weight, based on the total weight of monomer M, which are selected from monoethylenically unsaturated monomers having acidic groups;

[0134] v. one or more non-ionic monomers M5 in an amount of 0% to 9.95% by weight, especially 0.05% to 5% by weight, particularly 0.1% to 4% by weight, based on the total weight of monomer M, which have a solubility of at least 60 g / L in deionized water at 20 °C and 1 bar,

[0135] wherein the total amount of monomers M1 and M3 is in the range of 5% to 70% by weight, especially in the range of 10% to 65% by weight, particularly in the range of 15% to 60% by weight, based on the total weight of the ethylenically unsaturated monomers M, and wherein the total amount of monomers M1, M2 and M3 is at least 85% by weight, especially at least 90% by weight, particularly at least 95% by weight, based on the total weight of the ethylenically unsaturated monomers M;

[0136] or

[0137] i. Cyclopentyl methacrylate as monomer M1 in an amount of 10% to 68.95% by weight, especially 15% to 63.4% by weight, particularly 15% to 57.4% by weight, based on the total amount of monomer M;

[0138] ii. Monomer M2 in an amount of 30% to 70% by weight, especially 35% to 65% by weight, particularly 40% to 60% by weight, based on the total amount of monomer M, which is a mixture of isobutyl acrylate and at least one C2-C 10 alkyl acrylate different from isobutyl acrylate, such as n-butyl acrylate, isopentyl acrylate, 2-methylbutyl acrylate, 2-octyl acrylate, and 2-ethylhexyl acrylate;

[0139] iii. Monomer M3 in an amount of 1% to 35% by weight, especially 1.5% to 30% by weight, particularly 2% to 25% by weight, based on the total amount of monomer M, which is selected from methyl methacrylate, styrene, and combinations thereof;

[0140] iv. One or more monoethylenically unsaturated monomers M4 in an amount of 0.05% to 5% by weight, especially 0.1% to 4% by weight, particularly 0.5% to 3% by weight, based on the total amount of monomer M, which is selected from monoethylenically unsaturated monomers having acidic groups;

[0141] v. One or more nonionic monomers M5 in an amount of 0% to 9.95% by weight, especially 0.05% to 5% by weight, particularly 0.1% to 4% by weight, based on the total weight of monomer M, which has a solubility of at least 60 g / L in deionized water at 20 °C and 1 bar,

[0142] wherein the total amount of monomers M1 and M3 is in the range of 5% to 70% by weight, especially 10% to 65% by weight, particularly 15% to 60% by weight, based on the total amount of ethylenically unsaturated monomer M, and wherein the total amount of monomers M1, M2, and M3 is at least 85% by weight, especially at least 90% by weight, particularly at least 95% by weight, based on the total amount of ethylenically unsaturated monomer M;

[0143] or

[0144] i. Cyclopentyl methacrylate as monomer M1 in an amount of 10% to 68.95% by weight, especially 15% to 63.4% by weight, particularly 15% to 57.4% by weight, based on the total amount of monomer M;

[0145] ii. 30% to 70% by weight, particularly 35% to 65% by weight, especially 40% to 60% by weight, of monomer M2 based on the total amount of monomer M, which is n-butyl acrylate or a mixture of n-butyl acrylate and at least one C2-C 10 alkyl acrylate other than n-butyl acrylate, such as isopentyl acrylate, 2-methylbutyl acrylate, 2-octyl acrylate, and 2-ethylhexyl acrylate;

[0146] iii. 1% to 35% by weight, particularly 1.5% to 30% by weight, especially 2% to 25% by weight, of monomer M3 based on the total amount of monomer M, which is selected from methyl methacrylate, styrene, and combinations thereof;

[0147] iv. 0.05% to 5% by weight, particularly 0.1% to 4% by weight, especially 0.5% to 3% by weight, of one or more monoethylenically unsaturated monomers M4 based on the total amount of monomer M, which is selected from monoethylenically unsaturated monomers having acidic groups;

[0148] v. 0% to 9.95% by weight, particularly 0.05% to 5% by weight, especially 0.1% to 4% by weight, of one or more nonionic monomers M5 based on the total weight of monomer M, which have a solubility of at least 60 g / L in deionized water at 20 °C and 1 bar;

[0149] wherein the total amount of monomers M1 and M3 is in the range of 5% to 70% by weight, particularly in the range of 10% to 65% by weight, especially in the range of 15% to 60% by weight, based on the total amount of ethylenically unsaturated monomer M, and wherein the total amount of monomers M1, M2, and M3 is at least 85% by weight, particularly at least 90% by weight, especially at least 95% by weight, based on the total amount of ethylenically unsaturated monomer M.

[0150] In a specific group of embodiments 1, monomer M preferably comprises or consists of the following (Embodiment Group 1a):

[0151] i. 15% to 69.95% by weight, particularly 20% to 64.8% by weight, especially 25% to 59.4% by weight, of cyclopentyl methacrylate as monomer M1 based on the total amount of monomer M, wherein at least the carbon atoms of the cyclopentyl group in cyclopentyl methacrylate are of biological origin, and in particular the biological carbon content of cyclopentyl methacrylate is at least 51 mol-%, especially at least 55 mol-%;

[0152] ii. Isobutyl acrylate as monomer M2, based on 30% to 84.95% by weight, particularly 35% to 79.8% by weight, especially 40% to 74.4% by weight of the total amount of monomer M, wherein at least the carbon atoms of the isobutyl group in the isobutyl acrylate are of biological origin, and in particular the bio-based carbon content of isobutyl methacrylate is at least 54 mol-%, especially at least 57 mol-%

[0153] iii. One or more monoethylenically unsaturated monomers M4, based on 0.05% to 5% by weight, particularly 0.1% to 4% by weight, especially 0.5% to 3% by weight of the total amount of monomer M, which are selected from monoethylenically unsaturated monomers having acidic groups

[0154] iv. One or more non-ionic monomers M5, based on 0% to 9.95% by weight, particularly 0.05% to 5% by weight, especially 0.1% to 4% by weight of the total weight of monomer M, which have a solubility of at least 60 g / L in deionized water at 20 °C and 1 bar

[0155] wherein the total amount of monomers M1 and M2 is at least 85% by weight, particularly at least 90% by weight, especially at least 95% by weight based on the total amount of ethylenically unsaturated monomer M

[0156] or

[0157] i. Cyclopentyl methacrylate as monomer M1, based on 10% to 68.95% by weight, particularly 15% to 63.4% by weight, especially 15% to 57.4% by weight of the total amount of monomer M, wherein at least the carbon atoms of the cyclopentyl group in the cyclopentyl methacrylate are of biological origin, and in particular the bio-based carbon content of cyclopentyl methacrylate is at least 51 mol-%, especially at least 55 mol-%

[0158] ii. Isobutyl acrylate as monomer M2, based on 30% to 70% by weight, particularly 35% to 65% by weight, especially 40% to 60% by weight of the total amount of monomer M, wherein at least the carbon atoms of the isobutyl group in the isobutyl acrylate are of biological origin, and in particular the bio-based carbon content of isobutyl methacrylate is at least 54 mol-%, especially at least 57 mol-%

[0159] iii. Monomer M3, based on 1% to 35% by weight, particularly 1.5% to 30% by weight, especially 2% to 25% by weight of the total amount of monomer M, which is selected from methyl methacrylate, styrene and combinations thereof

[0160] iv. one or more monoethylenically unsaturated monomers M4 in an amount of from 0.05% to 5% by weight, in particular from 0.1% to 4% by weight, especially from 0.5% to 3% by weight, based on the total amount of monomers M, selected from monoethylenically unsaturated monomers having acidic groups;

[0161] v. one or more non-ionic monomers M5 in an amount of from 0% to 9.95% by weight, in particular from 0.05% to 5% by weight, especially from 0.1% to 4% by weight, based on the total weight of monomers M, having a solubility of at least 60 g / L in deionized water at 20 °C and 1 bar,

[0162] wherein the total amount of monomers M1 and M3 is in the range of from 5% to 70% by weight, in particular from 10% to 65% by weight, especially from 15% to 60% by weight, based on the total amount of ethylenically unsaturated monomers M, and wherein the total amount of monomers M1, M2 and M3 is at least 85% by weight, in particular at least 90% by weight, especially at least 95% by weight, based on the total amount of ethylenically unsaturated monomers M;

[0163] or

[0164] i. cyclopentyl methacrylate as monomer M1 in an amount of from 10% to 68.95% by weight, in particular from 15% to 63.4% by weight, especially from 15% to 57.4% by weight, based on the total amount of monomers M, wherein at least the carbon atoms of the cyclopentyl group in cyclopentyl methacrylate are of biological origin, in particular the biological carbon content of cyclopentyl methacrylate is at least 51 mol-%, especially at least 55 mol-%;

[0165] ii. monomer M2 in an amount of from 30% to 70% by weight, in particular from 35% to 65% by weight, especially from 40% to 60% by weight, based on the total amount of monomers M, which is a mixture of isobutyl acrylate and at least one C2-C 10 alkyl acrylate different from isobutyl acrylate such as n-butyl acrylate, isopentyl acrylate, 2-methylbutyl acrylate, 2-octyl acrylate and 2-ethylhexyl acrylate, wherein at least the carbon atoms of the isobutyl group in isobutyl acrylate are of biological origin, in particular the biological carbon content of isobutyl methacrylate is at least 54 mol-%, especially at least 57 mol-%;

[0166] iii. monomer M3 in an amount of from 1% to 35% by weight, in particular from 1.5% to 30% by weight, especially from 2% to 25% by weight, based on the total amount of monomers M, selected from methyl methacrylate, styrene and combinations thereof;

[0167] iv. from 0.05% to 5% by weight, in particular from 0.1% to 4% by weight, especially from 0.5% to 3% by weight, of one or more monoethylenically unsaturated monomers M4 based on the total amount of monomers M, selected from monoethylenically unsaturated monomers having acidic groups;

[0168] v. from 0% to 9.95% by weight, in particular from 0.05% to 5% by weight, especially from 0.1% to 4% by weight, of one or more non-ionic monomers M5 based on the total weight of monomers M, which have a solubility of at least 60 g / L in deionized water at 20 °C and 1 bar,

[0169] wherein the total amount of monomers M1 and M3 is in the range from 5% to 70% by weight, in particular from 10% to 65% by weight, especially from 15% to 60% by weight, based on the total amount of ethylenically unsaturated monomers M, and wherein the total amount of monomers M1, M2 and M3 is at least 85% by weight, in particular at least 90% by weight, especially at least 95% by weight, based on the total amount of ethylenically unsaturated monomers M;

[0170] or

[0171] i. cyclopentyl methacrylate as monomer M1 from 10% to 68.95% by weight, in particular from 15% to 63.4% by weight, especially from 15% to 57.4% by weight, based on the total amount of monomers M, wherein at least the carbon atoms of the cyclopentyl group in the cyclopentyl methacrylate are of biological origin, in particular the biological carbon content of the cyclopentyl methacrylate is at least 51 mol-%, especially at least 55 mol-%;

[0172] ii. monomers M2 from 30% to 70% by weight, in particular from 35% to 65% by weight, especially from 40% to 60% by weight, based on the total amount of monomers M, which are n-butyl acrylate or a mixture of n-butyl acrylate and at least one C2-C 10 alkyl acrylate different from n-butyl acrylate, such as isopentyl acrylate, 2-methylbutyl acrylate, 2-octyl acrylate and 2-ethylhexyl acrylate;

[0173] iii. monomers M3 from 1% to 35% by weight, in particular from 1.5% to 30% by weight, especially from 2% to 25% by weight, based on the total amount of monomers M, selected from methyl methacrylate, styrene and combinations thereof;

[0174] iv. from 0.05% to 5% by weight, in particular from 0.1% to 4% by weight, especially from 0.5% to 3% by weight, of one or more monoethylenically unsaturated monomers M4 based on the total amount of monomers M, selected from monoethylenically unsaturated monomers having acidic groups;

[0175] v. one or more nonionic monomers M5 in an amount of 0% to 9.95% by weight, particularly 0.05% to 5% by weight, especially 0.1% to 4% by weight, based on the total weight of monomer M, which have a solubility of at least 60 g / L in deionized water at 20 °C and 1 bar;

[0176] wherein the total amount of monomers M1 and M3 is in the range of 5% to 70% by weight, particularly in the range of 10% to 65% by weight, especially in the range of 15% to 60% by weight, based on the total amount of ethylenically unsaturated monomers M, and wherein the total amount of monomers M1, M2 and M3 is at least 85% by weight, particularly at least 90% by weight, especially at least 95% by weight, based on the total amount of ethylenically unsaturated monomers M.

[0177] In a specific group of embodiments 2, the types and amounts of monomers M1, M2, M3, M4 and, if present, M5 are as defined in the specific group of embodiments 1, except that monomer M1 is a mixture of cyclopentyl acrylate and cyclopentyl methacrylate instead of cyclopentyl methacrylate.

[0178] Among the specific group of embodiments 2, embodiment 2a is preferred, wherein the types and amounts of monomers M1, M2, M3, M4 and, if present, M5 are as defined in the specific group of embodiments 1a, except that monomer M1 is a mixture comprising at least 50% by weight, particularly at least 80% by weight, especially at least 90% by weight, based on the total amount of monomer M1, of cyclopentyl acrylate and cyclopentyl methacrylate instead of cyclopentyl methacrylate.

[0179] In addition to the above monomers M1, M2, M3, M4 and M5, monomer M may comprise one or more additional monomers different from the above monomers M. Suitable monomers M different from monomers M1, M2, M3, M4 and M5 include, but are not limited to

[0180] - monomer M6, which is selected from monoethylenically unsaturated nonionic monomers having a silane functional group or an epoxy group;

[0181] - monomer M7, which is selected from polyethylenically unsaturated monomers, i.e., monomers having at least two non-conjugated ethylenically unsaturated double bonds;

[0182] - monomer M8, which is selected from monoethylenically unsaturated copolymerizable UV initiators.

[0183] Suitable monomer M6 includes monoethylenically unsaturated silane-functional monomers (monomer M6a), such as monomers bearing at least one mono-, di- and / or tri-C1-C4-alkoxysilyl group in addition to the ethylenically unsaturated double bond, like vinyltrimethoxysilane, vinyltriethoxysilane, methacryloxymethyltrimethoxysilane, methacryloxymethyltriethoxysilane, methacryloxypropyltrimethoxysilane, methacryloxypropyltriethoxysilane, methacryloxyethyltrimethoxysilane, methacryloxyethyltriethoxysilane, and mixtures thereof. Preferred are methacryloxypropyltrimethoxysilane and vinyltriethoxysilane. If present, based on the total amount of ethylenically unsaturated monomer M, the amount of silane-functional monomer M6a will generally not exceed 1% by weight, and often ranges from 0.01% to 1% by weight, preferably from 0.05% to 0.7% by weight.

[0184] Suitable monomer M6 also includes monoethylenically unsaturated monomers bearing at least one epoxy group (monomer M6b), especially glycidyl groups, such as glycidyl acrylate, glycidyl methacrylate, 2-glycidyloxyethyl acrylate, and 2-glycidyloxyethyl methacrylate. If present, based on the total amount of ethylenically unsaturated monomer M, the amount of monomer M6b will generally not exceed 2% by weight, and often ranges from 0.01% to 2% by weight, preferably from 0.05% to 1% by weight.

[0185] Monomer M may also contain polyethylenically unsaturated monomers (monomer M7), i.e., monomers having at least two non-conjugated ethylenically unsaturated double bonds. Based on the total amount of ethylenically unsaturated monomer M, the amount of monomer M7 will generally not exceed 1% by weight, and often ranges from 0% to 1% by weight, especially from 0% to 0.5% by weight.

[0186] Examples of polyethylenically unsaturated monomer M7 include:

[0187] - Diesters of monoethylenically unsaturated C3-C6 monocarboxylic acids with saturated aliphatic or cycloaliphatic diols, especially diesters of acrylic or methacrylic acid, such as diacrylates and dimethacrylates of ethylene glycol (1,2-ethanediol), propylene glycol (1,2-propanediol), 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol (2,2-dimethyl-1,3-propanediol), 1,6-hexanediol, and 1,2-cyclohexanediol;

[0188] - Mono-esters of mono-ethylenically unsaturated C3-C6 monocarboxylic acids with mono-ethylenically unsaturated aliphatic or cycloaliphatic monohydroxy compounds, such as vinyl alcohol (ethenol), allyl alcohol (2-propen-1-ol), 2-cyclohexen-1-ol or norbornenol acrylates and methacrylates, such as allyl acrylate and allyl methacrylate; and

[0189] - Divinyl aromatic compounds, such as 1,3-divinylbenzene, 1,4-divinylbenzene.

[0190] The polymerized mono-ethylenically unsaturated copolymerizable UV initiator M8 causes crosslinking of the polymer chains upon exposure to sunlight. The monomer M8 bears an ethylenically unsaturated double bond, in particular an acrylate or methacrylate group and a moiety that decomposes upon UV radiation, thereby forming free radicals. Such groups are typically benzophenone groups, acetophenone groups, benzoin groups or carbonate groups attached to a benzene ring. Such compounds are disclosed, for example, in EP 346734, EP 377199, DE 4037079, DE3844444, EP 1213 and US2015 / 0152297. Examples include, but are not limited to, 4-acryloyloxybenzophenone (==4-benzoylphenyl acrylate), 4-methacryloyloxybenzophenone (==4-benzoylphenyl 2-methylacrylate), 4-(2-acryloyloxyethoxy)benzophenone (==2-(4-benzoylphenoxy)ethyl acrylate), 4-(2-methacryloyloxyethoxy)benzophenone (==2-(4-benzoylphenoxy)ethyl 2-methylacrylate), O-(2-(meth)acryloyloxyethyl)-O-(benzoylphenyl) carbonate and O-(2-(meth)acryloyloxyethyl)-O-(acetylphenyl) carbonate. Based on the total amount of the ethylenically unsaturated monomer M, the amount of the monomer M8 will generally not exceed 1% by weight and, if present, typically ranges from 0.01% to 1% by weight, especially from 0.02% to 0.5% by weight.

[0191] In particular, the monomer M consists of the following (Example Group 3):

[0192] i. Cyclopentyl methacrylate as monomer M1 in an amount of 15% to 69.95% by weight, especially 20% to 64.8% by weight, particularly 25% to 59.4% by weight, based on the total amount of monomer M, wherein at least the carbon atoms of the cyclopentyl group in cyclopentyl methacrylate are of biological origin, in particular the bio-based carbon content of cyclopentyl methacrylate is at least 51 mol-%, especially at least 55 mol-%;

[0193] ii. isobutyl acrylate as monomer M2, based on 30% to 84.95% by weight, especially 35% to 79.8% by weight, particularly 40% to 74.4% by weight of the total amount of monomer M, wherein at least the carbon atoms of the isobutyl group in isobutyl acrylate are of biological origin, in particular the bio-based carbon content of isobutyl methacrylate is at least 54 mol-%, especially at least 57 mol-%

[0194] iii. one or more monoethylenically unsaturated monomers M4, based on 0.05% to 5% by weight, especially 0.1% to 4% by weight, particularly 0.5% to 3% by weight of the total amount of monomer M, selected from acrylic acid, methacrylic acid, itaconic acid and combinations thereof

[0195] iv. one or more non-ionic monomers M5, based on 0% to 9.95% by weight, especially 0.05% to 5% by weight, particularly 0.1% to 4% by weight of the total weight of monomer M, having a solubility of at least 60 g / L in deionized water at 20 °C and 1 bar, and having functional groups selected from the group consisting of hydroxyalkyl groups, primary formamide groups, urea groups, ketone groups and combinations thereof; and

[0196] v. one or more monomers M7, based on 0% to 1% by weight, especially 0% to 0.5% by weight of the total weight of monomer M

[0197] wherein the total amount of monomers M1 and M2 is at least 85% by weight, especially at least 90% by weight, particularly at least 95% by weight based on the total amount of ethylenically unsaturated monomer M

[0198] or

[0199] i. cyclopentyl methacrylate as monomer M1, based on 10% to 68.95% by weight, especially 15% to 63.4% by weight, particularly 15% to 57.4% by weight of the total amount of monomer M, wherein at least the carbon atoms of the cyclopentyl group in cyclopentyl methacrylate are of biological origin, in particular the bio-based carbon content of cyclopentyl methacrylate is at least 51 mol-%, especially at least 55 mol-%

[0200] ii. isobutyl acrylate as monomer M2, based on 30% to 70% by weight, especially 35% to 65% by weight, particularly 40% to 60% by weight of the total amount of monomer M, wherein at least the carbon atoms of the isobutyl group in isobutyl acrylate are of biological origin, in particular the bio-based carbon content of isobutyl methacrylate is at least 54 mol-%, especially at least 57 mol-%

[0201] iii. from 1% to 35% by weight, especially from 1.5% to 30% by weight, particularly from 2% to 25% by weight, of monomer M3, selected from methyl methacrylate, styrene and combinations thereof, based on the total amount of monomer M;

[0202] iv. from 0.05% to 5% by weight, especially from 0.1% to 4% by weight, particularly from 0.5% to 3% by weight, of one or more monoethylenically unsaturated monomers M4, selected from acrylic acid, methacrylic acid, itaconic acid and combinations thereof, based on the total amount of monomer M;

[0203] v. from 0% to 9.95% by weight, especially from 0.05% to 5% by weight, particularly from 0.1% to 4% by weight, of one or more non-ionic monomers M5, which have a solubility of at least 60 g / L in deionized water at 20 °C and 1 bar and which have functional groups selected from the group consisting of hydroxyalkyl groups, primary carboxamide groups, urea groups, ketone groups and combinations thereof, based on the total weight of monomer M; and

[0204] vi. from 0% to 1% by weight, especially from 0% to 0.5% by weight, of one or more monomers M7, based on the total weight of monomer M;

[0205] wherein the total amount of monomers M1 and M3 is in the range from 5% to 70% by weight, especially from 10% to 65% by weight, particularly from 15% to 60% by weight, based on the total amount of ethylenically unsaturated monomer M, and wherein the total amount of monomers M1, M2 and M3 is at least 85% by weight, especially at least 90% by weight, particularly at least 95% by weight, based on the total amount of ethylenically unsaturated monomer M;

[0206] or

[0207] i. from 10% to 68.95% by weight, especially from 15% to 63.4% by weight, particularly from 15% to 57.4% by weight, of cyclopentyl methacrylate as monomer M1, wherein at least the carbon atoms of the cyclopentyl group in cyclopentyl methacrylate are of biological origin, in particular the bio-based carbon content of cyclopentyl methacrylate is at least 51 mol-%, especially at least 55 mol-%;

[0208] ii. from 30% to 70% by weight, especially from 35% to 65% by weight, particularly from 40% to 60% by weight, of monomer M2, which is isobutyl acrylate and at least one acrylic C2-C 10A mixture of alkyl esters such as n-butyl acrylate, isopentyl acrylate, 2-methylbutyl acrylate, 2-octyl acrylate and 2-ethylhexyl acrylate, wherein at least the carbon atoms of the isobutyl group in isobutyl acrylate are of biological origin, in particular the bio-based carbon content of isobutyl methacrylate is at least 54 mol-%, especially at least 57 mol-%

[0209] iii. 1% to 35% by weight, especially 1.5% to 30% by weight, in particular 2% to 25% by weight, of monomer M3 based on the total amount of monomer M, which is selected from methyl methacrylate, styrene and combinations thereof;

[0210] iv. 0.05% to 5% by weight, especially 0.1% to 4% by weight, in particular 0.5% to 3% by weight, of one or more monoethylenically unsaturated monomers M4 based on the total amount of monomer M, which are selected from monoethylenically unsaturated monomers having acidic groups;

[0211] v. 0% to 9.95% by weight, especially 0.05% to 5% by weight, in particular 0.1% to 4% by weight, of one or more nonionic monomers M5 based on the total weight of monomer M, which have a solubility of at least 60 g / L in deionized water at 20 °C and 1 bar

[0212] vi. 0% to 1% by weight, in particular 0% to 0.5% by weight, of one or more monomers M7 based on the total weight of monomer M;

[0213] wherein the total amount of monomers M1 and M3 is in the range of 5% to 70% by weight, especially in the range of 10% to 65% by weight, in particular in the range of 15% to 60% by weight, based on the total amount of ethylenically unsaturated monomer M, and wherein the total amount of monomers M1, M2 and M3 is at least 85% by weight, especially at least 90% by weight, in particular at least 95% by weight, based on the total amount of ethylenically unsaturated monomer M;

[0214] or

[0215] i. Cyclopentyl methacrylate as monomer M1 in an amount of 10% to 68.95% by weight, especially 15% to 63.4% by weight, in particular 15% to 57.4% by weight, based on the total amount of monomer M, wherein at least the carbon atoms of the cyclopentyl group in cyclopentyl methacrylate are of biological origin, in particular the bio-based carbon content of cyclopentyl methacrylate is at least 51 mol-%, especially at least 55 mol-%

[0216] ii. 30% to 70% by weight, especially 35% to 65% by weight, particularly 40% to 60% by weight, of monomer M2 based on the total amount of monomer M, which is n-butyl acrylate or a mixture of n-butyl acrylate and at least one C2-C 10 alkyl acrylate other than n-butyl acrylate, such as isopentyl acrylate, 2-methylbutyl acrylate, 2-octyl acrylate, and 2-ethylhexyl acrylate;

[0217] iii. 1% to 35% by weight, especially 1.5% to 30% by weight, particularly 2% to 25% by weight, of monomer M3 based on the total amount of monomer M, which is selected from methyl methacrylate, styrene, and combinations thereof;

[0218] iv. 0.05% to 5% by weight, especially 0.1% to 4% by weight, particularly 0.5% to 3% by weight, of one or more monoethylenically unsaturated monomers M4 based on the total amount of monomer M, which is selected from monoethylenically unsaturated monomers having acidic groups;

[0219] v. 0% to 9.95% by weight, especially 0.05% to 5% by weight, particularly 0.1% to 4% by weight, of one or more nonionic monomers M5 based on the total weight of monomer M, which have a solubility of at least 60 g / L in deionized water at 20 °C and 1 bar;

[0220] vi. 0% to 1% by weight, particularly 0% to 0.5% by weight, of one or more monomers M7 based on the total weight of monomer M;

[0221] wherein the total amount of monomers M1 and M3 is in the range of 5% to 70% by weight, especially in the range of 10% to 65% by weight, particularly in the range of 15% to 60% by weight, based on the total amount of ethylenically unsaturated monomer M, and wherein the total amount of monomers M1, M2, and M3 is at least 85% by weight, especially at least 90% by weight, particularly at least 95% by weight, based on the total amount of ethylenically unsaturated monomer M.

[0222] In a specific group of Examples 4, the types and amounts of monomers M1, M2, M3, M4, and if present, M5, M6, M7, or M8 are as defined in the specific group of Examples 3, except that monomer M1 is a mixture containing at least 50% by weight, especially at least 80% by weight, particularly at least 90% by weight, of cyclopentyl acrylate and cyclopentyl methacrylate based on the total amount of monomer M1 instead of cyclopentyl methacrylate.

[0223] Preferably, the copolymer particles contained in the polymer latex have a Z-average particle size in the range of 30 to 500 nm, particularly in the range of 40 to 350 nm, as determined by quasi-elastic light scattering (QELS). The particle size distribution of the copolymer particles contained in the polymer latex can be unimodal or nearly unimodal, which means that the distribution function of the particle size has a single maximum and no specific shoulder. The particle size distribution of the copolymer particles contained in the polymer latex can also be multimodal or nearly multimodal, which means that the distribution function of the particle size has at least two different maxima or at least one maximum and at least one distinct shoulder.

[0224] If not otherwise stated, the particle size and the particle size distribution are determined by quasi-elastic light scattering (QELS) (also known as dynamic light scattering (DLS)). The measurement method is described in the ISO 13321:1996 standard. The measurement can be carried out using a high-performance particle sizer (HPPS). For this purpose, a sample of the diluted aqueous polymer latex is prepared and the dilution is analyzed. In the context of QELS, depending on the particle size, the aqueous dilution can have a polymer concentration in the range of 0.001% to 0.5% by weight. For most purposes, a suitable concentration will be 0.01% by weight. However, higher or lower concentrations can be used to achieve an optimal signal-to-noise ratio. The dilution can be achieved by adding the polymer latex to water or an aqueous solution of a surfactant to avoid flocculation. Usually, the dilution is carried out using a 0.1% by weight aqueous solution of a non-ionic emulsifier (such as ethoxylated C16 / C18 alkanol with an ethoxylation degree of 18) as the diluent. Measurement configuration: HPPS from Malvern, automated, with a continuous flow cuvette and a Gilson autosampler. Parameters: measurement temperature 20.0 °C; measurement time 120 s (6 cycles, each cycle 20 s); scattering angle 173°; laser wavelength 633 nm (HeNe); refractive index of the medium 1.332 (aqueous); viscosity 0.9546 mPa·s. The measurement gives the average value of the second-order cumulant analysis (fitted average value), i.e., the Z-average. The "fitted average value" is the intensity-weighted average hydrodynamic particle size in nm.

[0225] The hydrodynamic particle size can also be determined by hydrodynamic chromatography fractionation (HDC), as described, for example, by H. Wiese in "Characterization of Aqueous Polymer Dispersions" in Polymer Dispersions and Their Industrial Applications (Wiley-VCH, 2002), pages 41 - 73. For further details, reference is made to the following examples and description.

[0226] In a specific group of embodiments, the particles of the copolymer contained in the polymer latex have a Z - average particle size in the range from 30 to 200 nm, particularly in the range from 40 to 150 nm, as determined by QELS. In this specific group of embodiments, the particle size distribution of the copolymer particles contained in the polymer latex is particularly unimodal or almost unimodal, which means that the distribution function of the particle size has a single maximum.

[0227] The copolymer contained in the polymer particles can form a single phase, or if the polymer particles contain different copolymers, it can form different phases, which are different in terms of their monomer composition. Preferably, the polymer particles contained in the aqueous polymer latex of the present invention comprise a polymer phase having a glass transition temperature Tg not exceeding 40 °C, particularly at most 25 °C, preferably in the range from - 25 °C to + 40 °C, especially in the range from - 20 °C to + 25 °C.

[0228] The glass transition temperature as mentioned herein is the actual glass transition temperature. The actual glass transition temperature can be experimentally determined by differential scanning calorimetry (DSC) method according to ISO 11357 - 2:2013, preferably with sample preparation according to ISO 16805:2003.

[0229] The actual glass transition temperature depends on the monomer composition of the polymer formed, and the theoretical glass transition temperature can be calculated from the monomer composition used in the emulsion polymerization. The theoretical glass transition temperature is usually calculated from the monomer composition by the Fox equation:

[0230] 1 / Tg t = x a / Tg a + x b / Tg b +....x n / Tg n ,

[0231] In this equation, xa , x b ,....x n are the mass fractions of monomers a, b,....n and Tg a , Tg b ,....Tg n is the actual glass transition temperature (in Kelvin) of the homopolymer synthesized once from only one of monomers 1, 2,....n. The Fox equation was described by T.G. Fox in Bull. Am. Phys. Soc. [Bulletin of the American Physical Society] 1956, 1, page 123 and in Ullmann's der technischen Chemie [Ullmann's Encyclopedia of Industrial Chemistry], volume 19, page 18, 4th edition, Verlag Chemie [Chemical Publishing House], Weinheim, 1980. The actual Tg values of the homopolymers of most monomers are known and are listed, for example, in Ullmann’s der technischen Chemie [Ullmann's Encyclopedia of Industrial Chemistry], 5th edition, volume A21, page 169, Verlag Chemie [Chemical Publishing House], Weinheim, 1992. Another source for the glass transition temperature of homopolymers is, for example, J. Brandrup, E.H. Immergut, Polymer Handbook, 1st edition, J. Wiley [John Wiley & Sons], New York 1966, 2nd edition J. Wiley [John Wiley & Sons], New York 1975, 3rd edition J. Wiley [John Wiley & Sons], New York 1989 and 4th edition J. Wiley [John Wiley & Sons], New York 2004.

[0232] Generally, the theoretical glass transition temperature Tg calculated according to Fox as described herein t is similar or even identical to the experimentally determined glass transition temperature as described herein, and they deviate from each other by no more than 5 K, and in particular they deviate by no more than 2 K. Therefore, by selecting appropriate monomers Ma, Mb…Mn and their mass fractions x a , x b ,....x nBoth the actual and the theoretical glass transition temperatures of the polymer phases (1) and (2) are adjusted in order to reach the desired glass transition temperatures Tg(1) and Tg(2), respectively. It is common general knowledge for the person skilled in the art to select an appropriate amount of monomers Ma, Mb…Mn for obtaining a copolymer and / or copolymer phase having the desired glass transition temperature.

[0233] Preferably, the aqueous polymer latex of the invention has a pH of at least 3, for example a pH in the range from pH 3 to pH 11.5.

[0234] The aqueous polymer dispersions of the invention generally have a solids content in the range from 30% to 75% by weight, in particular in the range from 40% to 65% by weight, preferably in the range from 45% to 60% by weight. The solids content describes the proportion of the non-volatile fraction. The solids content of the dispersion is determined by means of a balance with infrared moisture analysis. In this determination, a certain amount of the polymer dispersion is introduced into the instrument, heated to 140 °C and subsequently held at this temperature. Once the average decrease in weight has dropped below 1 mg within 140 seconds, the measuring program is ended. The ratio of the weight after drying to the original mass introduced gives the solids content of the polymer dispersion. The total solids content of the formulation is determined arithmetically from the amounts of substances added and their solids content and concentration.

[0235] If the polymer in the polymer latex has functional groups complementary to the functional groups of a crosslinking agent, the polymer dispersion may contain a crosslinking agent for achieving post-crosslinking of the polymer latex particles. In this context, the term "complementary" should be understood to mean that the functional groups of the latex and the functional groups of the crosslinking agent are prone to undergo a chemical reaction which forms a chemical bond between the atoms of the respective functional groups. Typically, the crosslinking agent has at least two functional groups complementary to the functional groups of the polymer of the polymer latex. Examples of suitable crosslinking agents are described below.

[0236] In addition to the polymer and optionally the crosslinking agent, the aqueous polymer dispersions of the invention may also contain further components which are conventionally present in aqueous polymer dispersions. These further components are, for example, surface-active compounds such as emulsifiers and protective colloids, in particular those used for producing the polymer latex, further defoamers etc. The further components may also be acids, bases, buffers, decomposition products from the polymerization reaction, deodorizing compounds and chain transfer agents. Furthermore, the polymer latex may contain biocides for avoiding microbial spoilage. Based on the total weight of the polymer dispersion, the amount of the respective individual component will typically not exceed 1.5 wt%. Based on the total weight of the polymer latex, the total amount of these stated components will typically not exceed 5 wt%.

[0237] Preferably, the amount of volatile organic substances, i.e., the content of organic compounds having a boiling point of up to 250 °C as determined by gas chromatography via ISO 17895:2005 under standard conditions (101,325 kPa), is less than 0.5% by weight, in particular less than 0.2% by weight, based on the total weight of the polymer latex.

[0238] In addition to the polymer, the aqueous polymer latex also contains an aqueous phase in which the polymer particles of the polymer latex are dispersed. The aqueous phase (also referred to as serum) consists essentially of water and any additional water-soluble components. Based on the total weight of the aqueous phase, the total concentration of any additional components will typically not exceed 10 wt%, in particular 8% by weight.

[0239] The aqueous polymer latex of the present invention can be prepared by any method for preparing an aqueous dispersion of a polymer made from polymerization monomer M. In particular, the aqueous polymer latex of the present invention is prepared by aqueous emulsion polymerization, in particular by free radical aqueous emulsion polymerization of monomer M. The term "free radical aqueous emulsion polymerization" means that the polymerization of monomer M is initiated by free radicals formed by the decay of a polymerization initiator, whereby free radicals are formed in the polymerization mixture. Therefore, it is also referred to as "free radical-initiated emulsion polymerization". The procedures for free radical-initiated emulsion polymerization of monomers in an aqueous medium have been widely described and are thus well known to those skilled in the art [see in this regard "Emulsion Polymerization" in Encyclopedia of Polymer Science and Engineering, Volume 8, pages 659 et seq. (1987); D.C. Blackley, in High Polymer Latices, Volume 1, pages 35 et seq. (1966); H. Warson, The Applications of Synthetic Resin Emulsions, Chapter 5, pages 246 et seq. (1972); D. Diederich, Chemie in unserer Zeit 24, pages 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). A typical procedure for the aqueous emulsion polymerization of ethylenically unsaturated monomers is also described in the patent literature discussed in the introduction section of this patent application.

[0240] Free-radical-initiated aqueous emulsion polymerization is typically carried out by emulsifying ethylenically unsaturated monomers in an aqueous medium forming the aqueous phase, typically by using surface-active compounds such as emulsifiers and / or protective colloids, and polymerizing the system using at least one initiator which decays by forming free radicals and thereby initiates the chain-growth addition polymerization of the ethylenically unsaturated monomer M. The preparation of the aqueous polymer dispersions according to the invention can differ from this general procedure only in the specific use of the above monomers M1 to M8. It is understood here that, for the purposes of this specification, the method should also cover seed, stepwise, one-shot and gradient protocols familiar to the person skilled in the art.

[0241] Free-radical-initiated aqueous emulsion polymerization is triggered by free-radical polymerization initiators (free-radical initiators). These can in principle be peroxides or azo compounds. Of course, redox initiator systems are also available. In principle, the peroxides used can be inorganic peroxides such as hydrogen peroxide, or peroxydisulfates such as the mono- or di-alkali metal or ammonium salts of peroxydisulfuric acid, for example the mono-sodium and di-sodium salts, potassium salts or ammonium salts, or organic peroxides such as alkyl hydroperoxides, for example tert-butyl hydroperoxide, p-menthyl hydroperoxide or cumyl hydroperoxide and also di-alkyl or di-aryl peroxides, such as di-tert-butyl or di-cumyl peroxide. The azo compounds used are essentially 2,2'-azobis(isobutyronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile) and 2,2'-azobis(amidinopropyl) dihydrochloride (AIBA, corresponding to V-50 from Wako Chemicals). Suitable oxidizing agents for redox initiator systems are essentially the peroxides specified above. The corresponding reducing agents which can be used are sulfur compounds in a low oxidation state, such as alkali metal sulfites, for example potassium and / or sodium sulfite; alkali metal bisulfites, for example potassium and / or sodium bisulfite; alkali metal metabisulfites, for example potassium and / or sodium metabisulfite; formaldehyde sulfoxylates, for example potassium and / or sodium formaldehyde sulfoxylate; alkali metal salts of aliphatic sulfinic acids, especially potassium and / or sodium salts; and alkali metal hydrosulfides, for example potassium and / or sodium hydrosulfide; salts of polyvalent metals, such as iron(II) sulfate, ammonium iron(II) sulfate, iron(II) phosphate; enediols, such as dihydroxymaleic acid, benzoin and / or ascorbic acid; and reducing sugars, such as sorbose, glucose, fructose and / or dihydroxyacetone.

[0242] Preferred free radical initiators are inorganic peroxides, especially persulfates.

[0243] Generally, the amount of free radical initiator used is 0.05 to 2 ppmh, preferably 0.1 to 1 ppmh, based on the total amount of monomer M.

[0244] The amount of free radical initiator required for the emulsion polymerization of monomer M can be initially charged completely into the polymerization vessel. However, it is also possible not to charge the free radical initiator or only to charge a part of the free radical initiator, for example not more than 30% by weight, especially not more than 20% by weight, based on the total amount of the free radical initiator, and then to add any remaining amount of the free radical initiator to the free radical polymerization reaction under polymerization conditions. Preferably, at least 70%, especially at least 80%, particularly at least 90% or the total amount of the polymerization initiator is fed into the free radical polymerization reaction under polymerization conditions. The feeding of monomer M can be carried out batchwise in one or more portions or continuously at a constant or variable flow rate during the free radical emulsion polymerization of monomer M according to consumption.

[0245] Generally, the term "polymerization conditions" should be understood to mean those temperatures and pressures at which the free radical-initiated aqueous emulsion polymerization proceeds at a sufficient polymerization rate. They depend in particular on the free radical initiator used. Advantageously, the type and amount of the free radical initiator, the polymerization temperature and the polymerization pressure are selected such that there is always a sufficient amount of initiating radicals to initiate or maintain the polymerization reaction.

[0246] Preferably, the free radical emulsion polymerization of monomer M is carried out by the so-called feeding method (also called monomer feeding method), which means that at least 80%, especially at least 90% or the total amount of monomer M to be polymerized is metered into the polymerization reaction under polymerization conditions during the metering period P. The addition can be carried out batchwise and is preferably carried out continuously at a constant or variable feeding rate. The duration of the period P can depend on the production equipment and can vary from, for example, 20 minutes to 12 h. Frequently, the duration of the period P will be in the range of 0.5 h to 8 h, especially 1 h to 6 h. In a multi-step emulsion polymerization process, the total duration of all steps is typically in the above range. The duration of individual steps is typically shorter. Preferably, at least 70%, especially at least 80%, particularly at least 90% or the total amount of the polymerization initiator is introduced into the emulsion polymerization while adding the monomer.

[0247] Aqueous free radical emulsion polymerization is typically carried out in the presence of one or more suitable surfactants. These surfactants typically contain emulsifiers and provide micelles in which polymerization occurs, and these micelles are used to stabilize monomer droplets during the aqueous emulsion polymerization and also to grow polymer particles. The surfactants used in emulsion polymerization are generally not separated from the polymer dispersion, but remain in the aqueous polymer dispersion obtainable by emulsion polymerization of monomer M.

[0248] The surfactant can be selected from emulsifiers and protective colloids. In contrast to emulsifiers, protective colloids are to be understood as meaning polymeric compounds having a molecular weight above 2000 daltons, while emulsifiers typically have a lower molecular weight. The surfactant can be an anionic or nonionic surfactant or a mixture of nonionic and anionic surfactants.

[0249] Anionic surfactants typically carry at least one anionic group, which is typically selected from phosphate, phosphonate, sulfate and sulfonate groups. Anionic surfactants carrying at least one anionic group are typically used in the form of their alkali metal salts (especially their sodium salts) or in the form of their ammonium salts.

[0250] Preferred anionic surfactants are anionic emulsifiers, especially those carrying at least one sulfate or sulfonate group. Similarly, anionic emulsifiers carrying at least one phosphate or phosphonate group can be used as the sole anionic emulsifier or in combination with one or more anionic emulsifiers carrying at least one sulfate or sulfonate group.

[0251] Examples of anionic emulsifiers carrying at least one sulfate or sulfonate group are, for example,

[0252] - alkyl sulfates, especially C8-C 22 - salts of alkyl esters, especially alkali metal salts and ammonium salts,

[0253] - monoesters of sulfuric acid with ethoxylated alkanols, especially ethoxylated C8-C 22 - salts of monoesters of sulfuric acid with alkanols (preferably having an ethoxylation level (EO level) in the range from 2 to 40), especially alkali metal salts and ammonium salts,

[0254] - alkyl sulfonic acids, especially C8-C 22 - salts of alkyl sulfonic acids, especially alkali metal salts and ammonium salts,

[0255] - dialkyl esters of sulfosuccinic acid, especially di-C4-C 18 - salts of alkyl esters, especially alkali metal salts and ammonium salts,

[0256] - alkylbenzenesulfonic acids, especially C4-C 22Salts of -alkylbenzenesulfonic acids, especially alkali metal salts and ammonium salts, and

[0257] - Mono- or disulfonated alkyl-substituted diphenyl ethers, for example having C4-C on one or both aromatic rings 24 - Salts of bis(benzenesulfonic acid) ethers of alkyls, especially alkali metal salts and ammonium salts. The latter are common knowledge, for example from US-A-4,269,749, and are commercially available, for example as 2A1 (Dow Chemical Company),

[0258] - Surfactants having polymerizable ethylenically unsaturated double bonds as described herein, for example compounds having the formula (I)-(IV), wherein X and Y are each SO3 - or O-SO3 - .

[0259] Examples of anionic emulsifiers bearing phosphate or phosphonate groups include, but are not limited to, the following salts selected from the group consisting of:

[0260] - Mono- and dialkyl phosphates, especially C8-C 22 - Salts of alkyl phosphates, especially alkali metal salts and ammonium salts,

[0261] - Monoesters of phosphoric acid of C2-C3-alkoxylated alkanols (preferably having an alkoxylation level in the range from 2 to 40, especially in the range from 3 to 30), for example ethoxylated C8-C 22 - Monoesters of phosphoric acid of alkanols (preferably having an ethoxylation level (EO level) in the range from 2 to 40), propoxylated C8-C 22 - Monoesters of phosphoric acid of alkanols (preferably having a propoxylation level (PO level) in the range from 2 to 40) and ethoxylated-co-propoxylated C8-C 22 - Monoesters of phosphoric acid of alkanols (preferably having an ethoxylation level (EO level) in the range from 1 to 20 and a propoxylation level from 1 to 20), especially alkali metal salts and ammonium salts,

[0262] - Alkylphosphonic acids, especially C8-C 22 - Salts of alkylphosphonic acids, especially alkali metal salts and ammonium salts, and

[0263] - Alkylbenzenephosphonic acids, especially C4-C 22 - Salts of alkylbenzenephosphonic acids, especially alkali metal salts and ammonium salts.

[0264] - Surfactants having polymerizable ethylenically unsaturated double bonds as described herein, for example compounds having the formula (I)-(IV), wherein X and Y are each HPO3 - 、PO32 、O-HPO3 - or O-PO3 2 。

[0265] The anionic emulsifier may also contain an emulsifier having a polymerizable double bond, such as emulsifiers of formulas (I) to (IV) and their salts, especially their alkali metal salts or ammonium salts:

[0266]

[0267] In formula (I), R 1 is H, C1-C 20 -alkyl, C5-C 10 -cycloalkyl, phenyl optionally substituted by C1-C 20 -alkyl, R 2 and R 2’ are both H or together are O, R 3 and R 4 are H or methyl, m is 0 or 1, n is an integer from 1 - 100, and X is SO3 - 、O-SO3 - 、O-HPO3 - or O-PO3 2- 。

[0268]

[0269] In formula (II), R is H, C1-C 20 -alkyl, C5-C 10 -cycloalkyl, phenyl optionally substituted by C1-C 20 -alkyl, k is 0 or 1, and X is SO3 - 、O-SO3 - 、O-HPO3 - or O-PO3 2- 。

[0270]

[0271] In formula (III), R 1 is H, C1-C 20 -alkyl, O-C1-C 20 -alkyl, C5-C 10 -cycloalkyl, O-C5-C 10 -cycloalkyl, O-phenyl optionally substituted by C1-C 20 -alkyl, n is an integer from 1 - 100, and Y is SO3 - 、HPO3 - or PO3 2- 。

[0272]

[0273] In formula (IV), R 1 is H, C1-C 20 -alkyl or 1-phenylethyl, R 2 is H, C1-C 20 -alkyl or 1-phenylethyl, A is C2-C4-alkanediyl such as 1,2-ethanediyl, 1,2-propanediyl, 1,2-butanediyl or 1,4-butanediyl, n is an integer from 1 to 100, and Y is SO3 - , HPO3 - or PO3 2- .

[0274] Specific examples of the copolymerizable emulsifier having the formula (I) are called sulfates or phosphates of polyethylene glycol monoacrylate. Specific examples of the copolymerizable emulsifier having the formula (I) can also be called phosphonates of polyethylene glycol monoacrylate, or allyl ether sulfates. Commercially available copolymerizable emulsifiers having the formula (I) are emulsifiers, PAM emulsifiers, PD and ADEKA PP-70.

[0275] Specific examples of the copolymerizable emulsifier having the formula (II) are also called alkyl allyl sulfosuccinates. Commercially available copolymerizable emulsifiers having the formula (II) are LF40.

[0276] Specific examples of the copolymerizable emulsifier having the formula (III) are also called branched unsaturated. Commercially available copolymerizable emulsifiers having the formula (III) are Reasoap emulsifiers and KH.

[0277] Specific examples of the copolymerizable emulsifier having the formula (IV) are also called polyoxyethylene alkyl phenyl ether sulfates and polyoxyethylene mono- or di-styryl phenyl ether sulfates. Commercially available copolymerizable emulsifiers having the formula (IV) are BC and AR emulsifiers.

[0278] Further suitable anionic surfactants can be found in Houben-Weyl, Methoden der organischen Chemie [Methods of Organic Chemistry], Volume XIV / 1, Makromolekulare Stoffe [Macromolecular Substances], Georg-Thieme-Verlag, Stuttgart, 1961, pages 192 - 208.

[0279] Preferably, the surfactant comprises at least one anionic emulsifier having at least one sulfate or sulfonate group. The at least one anionic emulsifier having at least one sulfate or sulfonate group can be the sole type of anionic emulsifier. However, a mixture of at least one anionic emulsifier having at least one sulfate or sulfonate group and at least one anionic emulsifier having at least one phosphate or phosphonate group can also be used. In such a mixture, based on the total weight of the anionic surfactants used in the process according to the invention, the amount of the at least one anionic emulsifier having at least one sulfate or sulfonate group is preferably at least 50% by weight. In particular, based on the total weight of the anionic surfactants used in the process according to the invention, the amount of the anionic emulsifier having at least one phosphate or phosphonate group does not exceed 20% by weight.

[0280] Preferred anionic surfactants are anionic emulsifiers selected from the group consisting of, including mixtures thereof:

[0281] - alkyl sulfates, especially C8 - C 22 - salts of alkyl esters, especially alkali metal salts and ammonium salts,

[0282] - sulfuric acid monoesters of ethoxylated alkanols, especially ethoxylated C8 - C 22 - salts of sulfuric acid monoesters of alkanols (preferably having an ethoxylation level (EO level) in the range of 2 to 40), especially alkali metal salts,

[0283] - sulfuric acid monoesters of ethoxylated alkylphenols, especially ethoxylated C4 - C 18 - sulfuric acid monoesters of alkylphenols (EO level preferably 3 to 40),

[0284] - alkylbenzenesulfonic acids, especially C4 - C 22 - alkylbenzenesulfonic acids, and

[0285] - mono - or disulfonated alkyl - substituted diphenyl ethers, for example bis(benzenesulfonic acid) ethers having C4 - C 24 - alkyl groups on one or two aromatic rings.

[0286] - a polymerizable emulsifier of formula (III).

[0287] Particularly preferred are anionic emulsifiers selected from the group consisting of, including mixtures thereof:

[0288] - alkyl sulfates, especially C8-C 22 - salts of alkyl esters, especially alkali metal salts and ammonium salts,

[0289] - sulfuric acid monoesters of ethoxylated alkanols, especially ethoxylated C8-C 22 - salts of sulfuric acid monoesters of alkanols (preferably having an ethoxylation level (EO level) in the range of 2 to 40), especially alkali metal salts,

[0290] - mono- or disulfonated alkyl-substituted diphenyl ethers, for example bis(phenylsulfonic acid) ethers with C4-C 24 - alkyl groups on one or two aromatic rings

[0291] - a polymerizable emulsifier of formula (III) wherein Y is SO3 - .

[0292] In addition to the above anionic surfactants, the surfactant may also contain one or more nonionic surface-active substances, especially selected from nonionic emulsifiers. Suitable nonionic emulsifiers are, for example, araliphatic or aliphatic nonionic emulsifiers such as ethoxylated mono-, di- and trialkylphenols (EO level: 3 to 50, alkyl: C4-C 10 ), ethoxylates of long-chain alcohols (EO level: 3 to 100, alkyl: C8-C 36 ), and polyethylene oxide / polypropylene oxide homopolymers and copolymers. These may contain alkylene oxide units copolymerized in a random distribution or in block form. Very suitable examples are EO / PO block copolymers. Preferred are ethoxylates of long-chain alkanols, especially those having an average ethoxylation level of 5 to 100 and an alkyl C8-C 30 , and among these, those having a straight-chain C 12 -C 20 alkyl and an average ethoxylation level of 10 to 50 are particularly preferred, as well as ethoxylated monoalkylphenols.

[0293] The surfactant used in the process of the present invention will generally comprise not more than 30% by weight, in particular not more than 20% by weight, of non-ionic surfactant based on the total amount of surfactant used in the process of the present invention, and in particular will not contain any non-ionic surfactant. It is also possible to use a combination of at least one anionic surfactant and at least a non-ionic surfactant. In this case, the weight ratio of the total amount of anionic surfactant to the total amount of non-ionic surfactant is in the range of 99:1 to 70:30, especially in the range of 98:2 to 75:25, in particular in the range of 95:5 to 80:20.

[0294] Preferably, the surfactant will be used in an amount such that the amount of surfactant is in the range of 0.2% to 5% by weight, in particular in the range of 0.3% to 4.5% by weight, based on the monomer M to be polymerized. In a multi-step emulsion polymerization, the surfactant will be used in an amount such that the amount of surfactant is generally in the range of 0.2% to 5% by weight, in particular in the range of 0.3% to 4.5% by weight, based on the total amount of monomer polymerized in the respective step.

[0295] Preferably, while adding the monomer, the major part, i.e. at least 80% of the surfactant used, is added to the emulsion polymerization. In particular, the monomer is added as an aqueous emulsion to the polymerization reaction which contains at least 80% of the surfactant used in the emulsion polymerization.

[0296] It has been found to be advantageous to carry out the free radical emulsion polymerization of monomer M in the presence of a seed latex. The seed latex is a polymer latex present in the aqueous polymerization medium before the start of the polymerization of monomer M. The seed latex can help to better regulate the particle size of the final polymer latex obtained in the free radical emulsion polymerization of the present invention.

[0297] In principle, any polymer latex can be used as the seed latex. For the purposes of the present invention, a seed latex is preferred in which the particle size of the polymer particles is relatively small. In particular, the Z-average particle diameter of the polymer particles of the seed latex (as determined by dynamic light scattering (DLS) at 20 °C (see below)) is preferably in the range of 10 to 80 nm, especially in the range of 10 to 50 nm. Preferably, the polymer particles of the seed latex are formed from ethylenically unsaturated monomers which comprise at least 95% by weight, based on the total weight of the monomers forming the seed latex, of one or more monomers selected from the group consisting of: C2-C of acrylic acid 10-alkyl esters, in particular ethyl acrylate, n-butyl acrylate, n-hexyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate; C1-C4-alkyl methacrylates such as methyl methacrylate; monoethylenically unsaturated nitriles such as acrylonitrile; and vinyl aromatic monomers as defined above, such as styrene; and mixtures thereof. In particular, the polymer particles of the seed latex are made of ethylenically unsaturated monomers which comprise, based on the total weight of the monomers forming the seed latex, at least 95% by weight of one or more monomers selected from the group consisting of: C1-C4-alkyl methacrylates such as methyl methacrylate, monoethylenically unsaturated nitriles such as acrylonitrile and vinyl aromatic monomers as defined above such as styrene, and mixtures thereof.

[0298] For this purpose, the seed latex is usually charged into the polymerization vessel before the start of the polymerization of monomer M. In particular, the seed latex is charged into the polymerization vessel and subsequently polymerization conditions are established, for example by heating the mixture to the polymerization temperature. It may be advantageous to charge at least a portion of the free radical initiator into the polymerization vessel before the start of the addition of monomer M. However, monomer M and the free radical polymerization initiator can also be added to the polymerization vessel in parallel.

[0299] The amount of the seed latex calculated as a solid can often be in the range from 0.01% to 10% by weight, preferably in the range from 0.05% to 5% by weight, in particular in the range from 0.05% to 3% by weight, based on the total weight of the monomers in the monomer composition M to be polymerized.

[0300] The free radical aqueous emulsion polymerization according to the invention can be carried out at a temperature in the range from 0 °C to 170 °C. The temperature employed is usually in the range from 50 °C to 120 °C, often in the range from 60 °C to 120 °C and often in the range from 70 °C to 110 °C. The free radical aqueous emulsion polymerization according to the invention can be carried out at a pressure less than, equal to or greater than 1 atm (atmospheric pressure), and thus the polymerization temperature can exceed 100 °C and can be up to 170 °C. The polymerization of the monomers is usually carried out at ambient pressure, but it can also be carried out at elevated pressure. In this case, the pressure can assume values of 1.2, 1.5, 2, 5, 10, 15 bar (absolute pressure) or even higher values. If the emulsion polymerization is carried out under reduced pressure, a pressure of 950 mbar, often 900 mbar and often 850 mbar (absolute pressure) is established. Advantageously, the free radical aqueous emulsion polymerization according to the invention is carried out at ambient pressure (about 1 atm) in the absence of oxygen, for example in an inert gas atmosphere, for example under nitrogen or argon.

[0301] The method for producing the polymer latex of the present invention can be a one-stage polymerization or a multi-stage emulsion polymerization. In the one-stage polymerization, the total composition of the monomer M fed into the polymerization reaction under polymerization conditions remains the same or almost the same, while in the multi-stage emulsion polymerization, the total composition of the monomer M fed into the polymerization reaction under polymerization conditions changes at least once, particularly such that the theoretical glass transition temperature of the resulting polymer formed in one stage differs from the theoretical glass transition temperature of the resulting polymer formed in another stage by at least 10 °C, particularly by at least 20 °C or at least 40 °C.

[0302] In a specific group of embodiments, the method of the present invention is carried out as a two-stage emulsion polymerization, i.e., the composition of the monomer fed into the polymerization reaction under polymerization conditions is modified once, or as a three-stage or four-stage emulsion polymerization, i.e., the composition of the monomer fed into the polymerization reaction under polymerization conditions is modified two or three times.

[0303] The polymerization of monomer M can optionally be carried out in the presence of a chain transfer agent. A chain transfer agent is understood to mean a compound that transfers a radical and reduces the molecular weight of the growing chain and / or controls chain growth in the polymerization. Examples of chain transfer agents are aliphatic and / or araliphatic halogen compounds such as n-butyl chloride, n-butyl bromide, n-butyl iodide, dichloromethane, dichloroethane, chloroform, bromoform, bromotrichloromethane, dibromodichloromethane, carbon tetrachloride, carbon tetrabromide, benzyl chloride, benzyl bromide, organic thio compounds such as primary, secondary or tertiary aliphatic mercaptans, for example ethyl mercaptan, n-propyl mercaptan, 2-propyl mercaptan, n-butyl mercaptan, 2-butyl mercaptan, 2-methyl-2-propyl mercaptan, n-pentyl mercaptan, 2-pentyl mercaptan, 3-pentyl mercaptan, 2-methyl-2-butyl mercaptan, 3-methyl-2-butyl mercaptan, n-hexyl mercaptan, 2-hexyl mercaptan, 3-hexyl mercaptan, 2-methyl-2-pentyl mercaptan, 3-methyl-2-pentyl mercaptan, 4-methyl-2-pentyl mercaptan, 2-methyl-3-pentyl mercaptan, 3-methyl-3-pentyl mercaptan, 2-ethylbutyl mercaptan, 2-ethyl-2-butyl mercaptan, n-heptyl mercaptan and its isomeric compounds, n-octyl mercaptan and its isomeric compounds, n-nonyl mercaptan and its isomeric compounds, n-decyl mercaptan and its isomeric compounds, n-undecyl mercaptan and its isomeric compounds, n-dodecyl mercaptan and its isomeric compounds, n-tridecyl mercaptan and its isomeric compounds, substituted mercaptans such as 2-hydroxyethyl mercaptan, aromatic mercaptans such as benzenethiol, o-, m- or p-methylbenzenethiol, alkyl esters of mercaptoacetic acid (thioglycolic acid) such as 2-ethylhexyl thioglycolate, alkyl esters of mercaptopropionic acid such as octyl mercaptopropionate, and also other sulfur compounds described in Polymer Handbook, 3rd Edition, 1989, J. Brandrup and E. H. Immergut, John Wiley & Sons, Section II, pages 133 to 141, and also aliphatic and / or aromatic aldehydes such as acetaldehyde, propionaldehyde and / or benzaldehyde, unsaturated fatty acids such as oleic acid, dienes having non-conjugated double bonds such as divinylmethane or vinylcyclohexane, or hydrocarbons having hydrogen atoms that are easily abstracted, such as toluene.

[0304] Alternatively, a mixture of the above chain transfer agents that do not interfere with each other can be used. Based on the total amount of monomer M, the total amount of chain transfer agent optionally used in the process of the present invention will generally not exceed 2% by weight, especially 1% by weight. However, it is possible that the amount of chain transfer agent added to the polymerization reaction during a certain period of the polymerization reaction can exceed the value of 2% by weight based on the total amount of monomer M added to the polymerization reaction during said period, and can be up to 8% by weight, especially at most 4% by weight.

[0305] When the aqueous polymer dispersion obtained on completion of the polymerization of monomer M is subjected to a post-treatment to reduce the residual monomer content, this is often advantageous. Such post-treatment is carried out chemically, for example by using a more efficient free-radical initiator system to complete the polymerization reaction (referred to as post-polymerization), and / or physically, for example by stripping the aqueous polymer dispersion with steam or an inert gas. The corresponding chemical and physical methods are familiar to those skilled in the art - see, for example, EP-A 771328, DE-A19624299, DE-A 19621027, DE-A 19741184, DE-A 19741187, DE-A 19805122, DE-A19828183, DE-A 19839199, DE-A 19840586 and DE-A19847115. The combination of chemical and physical post-treatment has the advantage that it removes not only unreacted ethylenically unsaturated monomers from the aqueous polymer dispersion, but also other detrimental volatile organic components (VOCs).

[0306] Since the polymers contained in the aqueous polymer dispersion may contain acidic groups derived from monomer M4 and optionally from the polymerization initiator, the aqueous polymer dispersion obtained by the process of the invention is often neutralized before it is formulated into a coating composition. Neutralization of the acid groups of the polymer is effected after and / or during the polymerization by neutralizing agents known to those skilled in the art. For example, the neutralizing agent can be added in a combined feed with the monomers to be polymerized or in a separate feed. Suitable neutralizing agents include organic amines, alkali metal hydroxides, ammonium hydroxide. In particular, neutralization is effected by using ammonia or an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide.

[0307] In addition, it may be appropriate to formulate the polymer latex of the invention with a post-curing agent. Ideally, such a post-curing agent (also referred to as a post-crosslinking agent) will cause a crosslinking reaction during and / or after film formation by forming coordination or covalent bonds with reactive sites on the surface of the polymer particles.

[0308] Crosslinking agents suitable for providing post-crosslinking are, for example, compounds having at least two functional groups selected from oxazoline, amino, aldehyde, aminoxy, carbodiimide, aziridinyl, epoxy and hydrazide groups, derivatives or compounds bearing an acetoacetyl group. These crosslinking agents react with the reactive sites of the polymers of the polymer dispersion of polymers having complementary functional groups capable of forming covalent bonds with the crosslinking agent. Suitable systems are known to those skilled in the art.

[0309] Since the polymers contained in the polymer dispersions of the present invention carry carboxyl groups, post-crosslinking can thus be achieved by formulating the polymer dispersions with one or more polycarbodiimides, which are described, for example, in US 4977219, US5047588, US 5117059, EP 0277361, EP 0507407, EP 0628582, US 5352400, US2011 / 0151128 and US2011 / 0217471. It is assumed that the crosslinking is based on the reaction of the carboxyl groups of the polymers with the polycarbodiimides. This reaction typically results in covalent crosslinking mainly based on N-acylurea bonds (J.W. Taylor and D.R. Bassett, in E.J. Glass (ed.), Technology for Waterborne Coatings [Technology for Waterborne Coatings], ACS Symposium Series 663 [ACS Symposium Series 663], Am. Chem. Soc. [American Chemical Society], Washington, D.C., 1997, Chapter 8, pp. 137 to 163).

[0310] Likewise, since the polymer particles contained in the polymer dispersions of the present invention carry carboxyl groups derived from monomer M4, suitable post-curing agents can also be water-soluble or water-dispersible polymers bearing oxazoline groups, such as the polymers described, for example, in US5300602 and WO 2015 / 197662.

[0311] Post-crosslinking can also be achieved analogously to EP 1227116, which describes an aqueous two-component coating composition containing a binder polymer having carboxylic acid and hydroxyl functional groups and a polyfunctional crosslinking agent having functional groups selected from isocyanate, carbodiimide, aziridinyl and epoxy groups.

[0312] If the polymers in the polymer dispersions carry keto groups, for example by using monomer M5c such as diacetone acrylamide (DAAM), post-crosslinking can be achieved by formulating the aqueous polymer dispersions with one or more diacylhydrazides, in particular aliphatic dicarboxylic acids such as adipic diacylhydrazide (ADDH), as described in US 4931494, US2006 / 247367 and US2004 / 143058. These components react substantially during and after film formation, although a certain degree of preliminary reaction can occur.

[0313] Other suitable reagents for achieving post-curing include

[0314] - epoxy silanes for crosslinking the carboxyl groups in the polymers;

[0315] - Dialdehydes for crosslinking urea groups or acetoacetoxy groups, such as glyoxal, such as those respectively derived from monomers M5b and M5c as defined herein, in particular (meth)acryloyl urethane or ethyl (meth)acryloyl acetoacetate;

[0316] - Diamines and / or polyamines for crosslinking keto groups or epoxy groups, such as those derived from monomers M5c or M6b as defined herein; and

[0317] - UV initiators, such as benzophenones, including benzophenone, 4-methoxybenzophenone, 4-methylbenzophenone, 2,4,6-trimethylbenzophenone, acetophenones, such as 2-hydroxy-2,2-dimethylacetophenone, 2-phenyl-2,2-dimethylacetophenone, cycloalkyl phenyl ketones, such as 1-benzoylcyclohexan-1-ol (=1-hydroxycyclohexyl phenyl ketone) and benzoin and mixtures thereof, in particular liquid mixtures, such as mixtures of 4-methylbenzophenone and benzophenone, mixtures of 2,4,6-trimethylbenzophenone and benzophenone, and mixtures of 1-hydroxycyclohexyl phenyl ketone and benzophenone.

[0318] Suitable systems are described, for example, in EP 355028, EP 441221, EP 0789724, US 5516453 and US 5498659 and / or are commercially available, for example in the case of UV initiators from Omnirad and IGM Resins (e.g., Esacure TZM, Esacure TZT, Omnirad 4MBZ).

[0319] The present invention also relates to an aqueous coating composition comprising

[0320] a) a binder polymer in the form of an aqueous polymer latex as defined herein; and

[0321] b) at least one additional component which is conventionally used in aqueous coating compositions and is not a binder.

[0322] The aqueous coating composition of the present invention can be formulated as a clear coating or a paint. In the latter case, in addition to the polymer latex, the aqueous coating composition further contains at least one inorganic pigment which, when the aqueous coating composition is used to coat a substrate, imparts a white hue or color to the resulting coating.

[0323] According to the definition in German standard specification DIN 55944:2003-11, pigments for the purposes of the present invention are almost insoluble, finely dispersed, organic or preferably inorganic colorants. Examples of pigments are in particular inorganic pigments, such as white pigments like titanium dioxide (C.I. Pigment White 6), and also colored pigments, for example

[0324] - Black pigments such as iron oxide black (C.I. Pigment Black 11), iron manganese black, spinel black (C.I. Pigment Black 27), carbon black (C.I. Pigment Black 7);

[0325] - Coloring pigments such as chromium oxide, hydrated chromium oxide green; chromium green (C.I. Pigment Green 48); cobalt green (C.I. Pigment Green 50); ultramarine green; cobalt blue (C.I. Pigment Blue 28 and 36); ultramarine blue, iron blue (C.I. Pigment Blue 27), manganese blue, ultramarine violet, cobalt violet, manganese violet, iron oxide red (C.I. Pigment Red 101); cadmium sulfoselenide (C.I. Pigment Red 108); molybdate red (C.I. Pigment Red 104); ultramarine red,

[0326] - Iron oxide brown, mixed brown, spinel and corundum phases (C.I. Pigment Brown 24, 29 and 31), chromium orange;

[0327] - Iron oxide yellow (C.I. Pigment Yellow 42); nickel titanate yellow (C.I. Pigment Yellow 53; C.I. Pigment Yellow 157 and 164); chromium titanate yellow; cadmium sulfide and cadmium zinc sulfide (C.I. Pigment Yellow 37 and 35); chromium yellow (C.I. Pigment Yellow 34), zinc yellow, alkaline earth metal chromates; Naples yellow; bismuth vanadate (C.I. Pigment Yellow 184);

[0328] - Interference pigments such as metal effect pigments based on coated metal flakes, pearlescent pigments based on mica flakes coated with metal oxides, and liquid crystal pigments.

[0329] The aqueous coating composition may also contain one or more fillers. Examples of suitable fillers are aluminosilicates such as feldspar, silicates such as kaolin, talc, mica, magnesite, alkaline earth metal carbonates such as calcium carbonate (e.g., in the form of calcite or chalk), magnesium carbonate, dolomite, alkaline earth metal sulfates such as calcium sulfate, silica, etc. In the coating composition of the present invention, finely divided fillers are naturally preferred. The fillers can be used in the form of a single component. However, in practice, it has been found that filler mixtures are particularly useful, such as calcium carbonate / kaolin, calcium carbonate / talc. Gloss paints usually contain only a small amount of very finely divided fillers or no fillers at all. Fillers also include matting agents that significantly reduce gloss as needed. Matting agents are usually transparent and can be organic or inorganic. Examples of matting agents are inorganic silicates, such as those from W.R.Grace&Company brand and those from Evonik GmbH brand. Organic matting agents can be obtained, for example, from BYK-Chemie GmbH under the brand and brand, and obtained from Deuteron GmbH under the Deuteron brand.

[0330] The proportion of pigments and fillers in an aqueous coating composition can be described in a manner known per se by the pigment volume concentration (PVC). The PVC describes the ratio of the volume of pigments (VP) and the volume of fillers (VF) relative to the total volume in percentage, where the total volume consists of the volume of binder (VB), the volume of pigments (VP), and the volume of fillers (VF) in the dry coating film: PVC [%] = (VP + VF) x 100 / (VP + VF + VB).

[0331] If the aqueous coating compositions are formulated as paints, they generally have a pigment volume concentration (PVC) of at least 5%, in particular at least 10%, and will typically not exceed 90%, especially 85%. In a preferred group of embodiments, the PVC will not exceed a value of 60%, in particular 50%, and specifically in the range of 5% to 60% or 5% to 50%. However, the inventive effect of the polymer dispersions is also manifested in varnishes, which typically have a pigment / filler content of less than 5% by weight based on the varnish and accordingly have a PVC of less than 5%. In yet another group of embodiments, the PVC will be in the range of >60% to 90%, especially in the range of 65% to 85%.

[0332] According to one group of embodiments, the aqueous coating compositions of the present invention are designed as paints containing white pigments - i.e., they contain at least one white pigment and optionally one or more fillers. As white pigments, they particularly include titanium dioxide (preferably in the rutile form), optionally in combination with one or more fillers. Particularly preferably, the coating compositions of the present invention contain a white pigment, more particularly titanium dioxide (preferably in the rutile form) in combination with one or more fillers (such as chalk, talc, or a mixture thereof).

[0333] In another preferred group of embodiments, the aqueous coating compositions of the present invention are designed as clear coatings or wood stain formulations. Compared to paints, clear coatings are substantially free of pigments and fillers, while wood stains contain not too many fillers, i.e., they have a PVC of less than 5%.

[0334] According to a specific group of embodiments, the present invention also relates to an aqueous coating composition (hereinafter also referred to as the aqueous coating composition), which comprises:

[0335] i) at least one aqueous polymer latex as defined above; and

[0336] ii) titanium dioxide pigment.

[0337] According to a further group of specific embodiments, the invention also relates to the use of an aqueous polymer latex as a binder in an aqueous coating composition containing titanium dioxide pigment.

[0338] In the above embodiments, the aqueous polymer latex is combined with a TiO2 pigment slurry or paste. The TiO2 concentration of the aqueous TiO2 pigment slurry or paste used to prepare the aqueous coating composition will generally be in the range of 30% to 85% by weight, often 40% to 80% by weight, and in each case based on the total weight of the aqueous TiO2 pigment slurry or paste. The titanium dioxide pigment of the aqueous dispersion used to prepare the pigment slurry or paste can be any TiO2 pigment conventionally used in coating compositions, especially aqueous coating compositions. Frequently, a TiO2 pigment is used in which the TiO2 particles preferably are in the rutile form. In another preferred embodiment, the TiO2 particles can also be coated with, for example, aluminum, silicon, and zirconium compounds.

[0339] Generally, the weight ratio of the polymer to the titanium dioxide pigment is in the range of ≥0.1:5.0 to ≤5.0:0.1; preferably, the weight ratio of the polymer to the titanium dioxide pigment is in the range of ≥0.5:5.0 to ≤5.0:0.5; particularly more preferably, the weight ratio of the polymer to the titanium dioxide pigment is in the range of ≥0.5:3.0 to ≤3.0:0.5 and especially in the range of ≥0.5:1.5 to ≤1.5:0.5.

[0340] Preferably, the titanium dioxide pigment has an average primary particle size in the range of ≥0.1 μm to ≤0.5 μm as determined by light scattering or by electron microscopy.

[0341] Generally, the aqueous coating composition further comprises at least one additive selected from the group consisting of: thickeners, defoamers, leveling agents, film-forming aids, biocides, wetting or dispersing agents, fillers, and coalescing agents.

[0342] The aqueous coating composition can be simply prepared by mixing TiO2 pigment powder or an aqueous slurry or paste of TiO2 pigment with the aqueous polymer latex of the invention, preferably by applying shear to the mixture, for example by using a dissolver conventionally used for preparing aqueous paints. An aqueous slurry or paste of TiO2 pigment and the aqueous polymer latex of the invention can also be prepared and then incorporated into another polymer latex of the invention or any other polymer latex binder, or mixed with another polymer latex of the invention or any other polymer latex binder.

[0343] An aqueous dispersion of the polymer complex can also be prepared by incorporating the aqueous polymer latex of the present invention as an adhesive or co-adhesive into an aqueous base formulation of a paint already containing TiO2 pigment, for example, by mixing the aqueous polymer latex of the present invention with a pigment formulation already containing additional additives conventionally used in paint formulations.

[0344] To stabilize the TiO2 pigment particles in the aqueous pigment slurry or paste, the mixing can optionally be carried out in the presence of additives (such as dispersants) conventionally used in aqueous pigment slurries or pigment pastes. Suitable dispersants include, but are not limited to, for example, polyphosphates such as sodium polyphosphate, potassium polyphosphate or ammonium polyphosphate, alkali metal salts and ammonium salts of acrylic homopolymers or copolymers or maleic anhydride polymers, polyphosphonates such as sodium 1-hydroxyethane-1,1-diphosphonate, and naphthalenesulfonates, especially their sodium salts.

[0345] In each case based on the total weight of the aqueous polymer latex, the polymer concentration in the aqueous polymer latex for preparing the aqueous dispersion of the polymer complex is generally in the range of 10% to 70% by weight, preferably 20% to 65% by weight and most preferably 30% to 60% by weight.

[0346] In addition to the polymer latex, titanium dioxide pigment and optionally a conventional binder of the present invention, the aqueous coating composition may also contain one or more pigments and / or fillers different from the TiO2 pigment, as described above.

[0347] Preferably, the aqueous coating composition comprises at least one aqueous polymer latex as defined herein and further comprises a rheology modifier. Suitable rheology modifiers include associative thickener polymers and non-associative rheology modifiers. The aqueous liquid composition preferably comprises a thickener selected from the group consisting of associative thickeners and non-associative thickeners and combinations thereof.

[0348] Associative thickener polymers are well-known and are often described in the scientific literature, such as in "Associative Thickeners" by E.J. Schaller et al. in Handbook of Coating Additives, Volume 2 (edited by L.J. Calbo), Marcel Decker 192, pages 105 - 164, and in "PUR-Verdicker" by J. Bieleman in Additives for Coatings (edited by J. Bielemann), Wiley 2000, pages 50 - 58. NiSAT thickener polymers of the HEUR and HMPE types are also described in patent literature such as US 4,079,028, US 4,155,892, EP 61,822, EP 307,775, WO 96 / 31,550, EP 612,329, EP 1,013,264, EP 1,541,643, EP 1,584,331, EP 2,184,304, DE 4,137,247, DE 102,004,008,015, DE 102,004,031,786, US2011 / 0166,291, and WO 2012 / 052,508. In addition, associative thickener polymers are commercially available.

[0349] Associative thickener polymers include anionic acrylate thickener polymers, so-called HASE polymers (hydrophobically modified polyacrylate thickeners), which are copolymers of acrylic acid and acrylic acid alkyl ester monomers, where the alkyl group of the acrylic acid alkyl ester can have 6 to 24 carbon atoms. Associative thickener polymers also include nonionic associative thickeners, so-called NiSAT thickeners (nonionic synthetic associative thickeners), which are generally linear or branched block copolymers having at least one internal hydrophilic part, especially a polyether part, in particular at least one polyethylene oxide part, and two or more terminal hydrocarbon groups, each having at least 4 carbon atoms, especially 4 to 24 carbon atoms, such as a linear or branched alkyl group having 4 to 24 carbon atoms or a phenyl group substituted with an alkyl group having 7 to 24 carbon atoms. NiSAT thickeners include hydrophobically modified polyethylene oxide urethane rheology modifiers (also known as HEUR or PUR thickeners) and hydrophobically modified polyethylene oxide (which is also known as HMPE).

[0350] The amount of associative thickener polymer will depend on the desired viscosity curve and is often in the range of 0.05% to 2.5% by weight, especially 0.1% to 2% by weight, and particularly 0.2% to 2% by weight of the thickener, based on the latex paint.

[0351] Suitable non - associative rheology modifiers are in particular cellulose - based thickeners, especially hydroxyethyl cellulose, and also thickeners based on acrylate emulsions (ASE). Among the non - associative rheology modifiers, preferred are non - associative cellulose - based thickeners.

[0352] The total amount of the thickener polymer will depend on the desired viscosity profile and is often in the range of from 0.05% to 6% by weight, in particular from 0.1% to 5.5% by weight, and especially from 0.15% to 5% by weight of thickener, based on the latex paint.

[0353] The aqueous coating composition of the present invention may also contain conventional auxiliaries. The conventional auxiliaries will depend in a known manner on the type of coating and include, but are not limited to:

[0354] - wetting agents or dispersants,

[0355] - film - forming aids, also known as coalescing agents,

[0356] - leveling agents,

[0357] - UV stabilizers,

[0358] - biocides and

[0359] - defoamers / de - aerators.

[0360] Suitable wetting agents or dispersants are, for example, sodium polyphosphate, potassium polyphosphate or ammonium polyphosphate, alkali metal salts and ammonium salts of acrylic copolymers or maleic anhydride copolymers, polyphosphonates such as sodium 1 - hydroxyethane - 1,1 - diphosphonate, and naphthalenesulfonates, especially their sodium salts.

[0361] Suitable film - forming aids are solvents and plasticizers. Compared with solvents, plasticizers have low volatility and preferably have a boiling point above 250 °C at 1013 mbar, while solvents have higher volatility than plasticizers and preferably have a boiling point below 250 °C at 1013 mbar. Suitable film - forming aids are, for example, white spirit, pine oil, propylene glycol, ethylene glycol, butylene glycol, butylene glycol acetate, butylene glycol diacetate, butyl diglycol, butyl carbitol, 1 - methoxy - 2 - propanol, 2,2,2 - trimethyl - 1,3 - pentanediol monoisobutyrate and glycol ethers and esters, such as those commercially available under the name from BASF SE and and name and those commercially available from Dow under the name The trade name is commercially available. Based on the total formulation, the amount is preferably <5% by weight and more preferably <1% by weight. A formulation without a film-forming aid is also entirely possible. Frequently, the coating composition does not require any film-forming aid.

[0362] Other suitable auxiliaries and components are described, for example, by J. Bieleman in “Additives for Coatings”, Whiley-VCH, Weinheim 2000; by T.C. Patton in “Paint Flow and Pigment Dispersions”, 2nd Edition, John Whiley & Sons 1978; and by M. Schwartz and R. Baumstark in “Waterbased Acrylates for Decorative Coatings”, Curt R. Vincentz Verlag, Hanover 2001.

[0363] The aqueous coating composition of the present invention can also be formulated as a low-VOC paint. In this case, the concentration of volatile compounds in the coating composition is preferably below 0.1 wt.-%, more preferably below 0.05 wt.-%, based on the total amount of the aqueous coating composition. For the purposes of the present invention, volatile compounds are compounds having a boiling point below 250 °C at 1013 mbar.

[0364] The aqueous coating composition of the present invention is particularly useful in architectural coatings, i.e., for coating the exterior or interior parts of buildings. In this case, the substrate can be a mineral substrate such as plaster of Paris, raw gypsum, gypsum board or concrete, wood, wood-based materials, metal, wallpaper or plastics such as PVC.

[0365] The aqueous coating composition can be applied to the substrate to be coated in a conventional manner, for example, by applying it with a brush or a roller, by spraying, by dipping, by roll coating, or by bar coating onto the desired substrate. The preferred application is by brush and / or by roller.

[0366] Generally, the coating of the substrate is carried out in such a way that the substrate is first coated with the aqueous coating composition of the present invention, and then the aqueous coating thus obtained is subjected to a drying step, especially in a temperature range of ≥ -10 °C and ≤ +50 °C, advantageously ≥ +5 °C and ≤ +40 °C and particularly advantageously ≥ +10 °C and ≤ +35 °C.

[0367] A substrate coated with the aqueous coating composition of the present invention has excellent anti - blooming properties when exposed to water or weathering conditions. In addition, the coating has good adhesion properties such as high dry alkyd adhesion, good opacity, high anti - blocking property, good stain - removal property, high wet scrub resistance and low dust - accumulation property.

[0368] Example

[0369] The present invention will be illustrated by the following non - limiting examples.

[0370] 1. Abbreviations:

[0371] MeHQ 4 - methoxyphenol (monomethyl ether of hydroquinone)

[0372] wt% % by weight

[0373] Herein and hereinafter, the terms "room temperature" and "ambient temperature" mean a temperature in the range of 22 °C - 23 °C.

[0374] 2. Analysis of polymer latex

[0375] 2.1 Solids content

[0376] The solids content was determined by drying a specified amount (about 2 g) of the aqueous polymer dispersion in an aluminum crucible with an inner diameter of about 5 cm in an oven at 130 °C to constant weight (2 hours). Two separate measurements were carried out. The values reported in the examples are the average of the two measurements.

[0377] 2.2 Particle size

[0378] Unless otherwise stated, the average particle size of the polymer latex was determined by dynamic light scattering (DLS) using a Malvern HPPS as described above.

[0379] 2.3 Glass transition temperature Tg

[0380] The glass transition temperature was determined by the DSC method (differential scanning calorimetry, 20 K / min, mid - point measurement, DIN 53765:1994 - 03) using a DSC instrument (Q 2000 series from TA Instruments).

[0381] 2.4 pH measurement

[0382] pH measurement was carried out on the reaction mixture using a pH meter.

[0383] 3. Ingredients

[0384] The following components were used in the examples of the present invention:

[0385]

[0386]

[0387]

[0388] Isobutyl acrylate can be prepared by a process similar to that for producing isoamyl acrylate by transesterification of ethyl acrylate with isobutanol as described in WO 2022 / 018013.

[0389] Process for producing cyclopentyl methacrylate

[0390] 1000 g of cyclopentanol was added to a 4 L heatable double-jacketed glass reactor with a heatable lid, which was equipped with a three-stage cross-arm stirrer, a water separator, a powerful cooler, a heating element, and lean air bubbling.

[0391] 3.1 g of sodium borohydride in 40% NaOH was added and stirred. After 2 h, 0.89 g of MeHQ, 1098 g of methacrylic acid, 47.8 g of 70% methanesulfonic acid, 0.24 g of copper(I) chloride, 1.18 g of 50% hypophosphorous acid, and 800 g of cyclohexane were added. The water separator was filled with cyclohexane.

[0392] A bath temperature of 115 °C was applied and the reaction mixture was heated while air was bubbled. At a reservoir temperature of 90 °C - 97 °C, an azeotrope of water and cyclohexane was distilled off. During the reaction, an additional 600 g of cyclohexane was added. Over an 8 h period, 214 g of water was distilled off and the reaction was stopped by cooling to room temperature.

[0393] The reaction mixture was cooled and extracted successively with 2000 g of water, 1255 g of 6.5% NaOH solution, and 2000 g of water. The aqueous phase was discarded.

[0394] A product solution in cyclohexane was obtained, 0.3 g of MeHQ was added, and then the solution was concentrated in vacuo at 60 °C and 380 to 10 mbar.

[0395] Cyclopentyl methacrylate was obtained in a yield of 1528 g (85%), with a GC purity of 96.5 GC area%.

[0396] Process for producing cyclopentyl acrylate

[0397] 100 g of cyclopentanol was placed in a 500 mL four-necked round-bottom flask equipped with a glass stirrer, a water separator with a powerful cooler, an air bubbling tube, and a thermometer.

[0398] Add 0.31 g of a 12% sodium borohydride solution in 40% NaOH and stir. After 2 h, add 0.09 g of MeHQ, 91.9 g of glacial acrylic acid, 4.78 g of 70% methanesulfonic acid, 0.019 g of copper(I) chloride, 0.095 g of 50% hypophosphorous acid, and 40 g of cyclohexane. The water separator is filled with cyclohexane.

[0399] Apply a bath temperature of 115 °C and heat the reaction mixture to an internal temperature of 96 °C with air bubbling, which internal temperature rises to 121 °C during the reaction.

[0400] Continuously distill off the azeotrope of water and cyclohexane. Discard the aqueous phase and transfer the organic phase back to the flask.

[0401] After distilling off 20 g of water, cool the reaction mixture to room temperature. Extract the organic phase with 200 g of water, 25.8 g of 12.5% NaOH, and finally with 200 g of water.

[0402] Add 0.02 g of MeHQ and distill off cyclohexane in vacuo.

[0403] Obtain 123.3 g of cyclopentyl acrylate with a purity of >95 GC area-%.

[0404] 4. Preparation Examples

[0405] 4.1 Adhesive Examples

[0406] Example E1 of the present invention

[0407] An adhesive based on a polymer having cyclopentyl methacrylate and isobutyl acrylate

[0408] Charge 244.3 g of deionized water and 27.3 g of a polystyrene seed dispersion (33 wt%, particle size: 30 nm) into a reactor equipped with a stirrer, a temperature controller, a nitrogen inlet, and multiple injection possibilities. Purge the reaction mixture with nitrogen and heat to 85 °C. At 85 °C, add 5.0 g of Feed 2. After 5 min, add Feed 1 and Feed 2 within 180 min.

[0409] - Feed 1: 400.5 g of deionized water, 18.5 g of Dowfax 2A1, 20.8 g of Lutensol TO 82, 6.9 g of acrylic acid, 13.9 g of acrylamide (50 wt% aqueous solution), 291.1 g of cyclopentyl methacrylate, 360.5 g of isobutyl acrylate.

[0410] - Feed 2: 19.8 g of an aqueous sodium persulfate solution (7 wt%). Carry out post-polymerization of the reaction mixture at 85 °C for 30 min.

[0411] Then, feedstock 3 and feedstock 4 are added within 60 min.

[0412] - Feedstock 3: 6.9 g of an aqueous solution of tert-butyl hydroperoxide (10 wt%).

[0413] - Feedstock 4: 6.2 g of an aqueous solution of Rongalit C (10 wt%).

[0414] Then, the reaction mixture is cooled to ambient temperature and neutralized to pH 8 - 9 with sodium hydroxide.

[0415] Tg (dried dispersion): 19 °C

[0416] Average particle size: 136 nm

[0417] Solid content: 47.4 wt%

[0418] Example E2 of the present invention

[0419] An adhesive based on a polymer having cyclopentyl methacrylate, isobutyl acrylate, and methyl methacrylate

[0420] Charge 244.3 g of deionized water and 27.3 g of a polystyrene seed dispersion (33 wt%, particle size: 30 nm) into a reactor equipped with a stirrer, a temperature controller, a nitrogen inlet, and multiple injection possibilities. Purge the reaction mixture with nitrogen and heat it to 85 °C. At 85 °C, add 5.0 g of feedstock 2. After 5 min, add feedstock 1 and feedstock 2 within 180 min.

[0421] - Feedstock 1: 400.5 g of deionized water, 18.5 g of Dowfax 2A1, 20.8 g of Lutensol TO 82, 6.9 g of acrylic acid, 13.9 g of acrylamide (50 wt% aqueous solution), 149.0 g of cyclopentyl methacrylate, 149.0 g of methyl methacrylate, 381.0 g of isobutyl acrylate.

[0422] - Feedstock 2: 19.8 g of an aqueous solution of sodium persulfate (7 wt%). Carry out post-polymerization of the reaction mixture at 85 °C for 30 min.

[0423] Then, feedstock 3 and feedstock 4 are added within 60 min.

[0424] - Feedstock 3: 6.9 g of an aqueous solution of tert-butyl hydroperoxide (10 wt%).

[0425] - Feedstock 4: 6.2 g of an aqueous solution of Rongalit C (10 wt%).

[0426] Then the reaction mixture was cooled to ambient temperature and neutralized to pH 8 - 9 with sodium hydroxide.

[0427] Tg (of the dried dispersion): 21 °C

[0428] Average particle size: 124 nm

[0429] Solid content: 48.4 wt%

[0430] Comparative Example C1

[0431] An adhesive based on a polymer having n - butyl acrylate and styrene

[0432] 244.3 g of deionized water and 27.3 g of a polystyrene seed dispersion (33 wt%, particle size: 30 nm) were charged into a reactor equipped with a stirrer, a temperature controller, a nitrogen inlet, and multiple injection possibilities. The reaction mixture was purged with nitrogen and heated to 85 °C. At 85 °C, 5.0 g of Feed 2 was added. After 5 min, Feed 1 and Feed 2 were added over 180 min.

[0433] - Feed 1: 400.5 g of deionized water, 18.5 g of Dowfax 2A1, 20.8 g of Lutensol TO 82, 6.9 g of acrylic acid, 13.9 g of acrylamide (50 wt% aqueous solution), 318.8 g of styrene, 360.4 g of n - butyl acrylate.

[0434] - Feed 2: 19.8 g of an aqueous solution of sodium persulfate (7 wt%). The reaction mixture was post - polymerized at 85 °C for 30 min.

[0435] Then Feed 3 and Feed 4 were added over 60 min.

[0436] - Feed 3: 6.9 g of an aqueous solution of tert - butyl hydroperoxide (10 wt%).

[0437] - Feed 4: 6.2 g of an aqueous solution of Rongalit C (10 wt%).

[0438] Then the reaction mixture was cooled to ambient temperature and neutralized to pH 8 - 9 with sodium hydroxide.

[0439] Tg (of the dried dispersion): 18 °C

[0440] Average particle size: 132 nm

[0441] Solid content: 48.1 wt%

[0442] Comparative Example C2

[0443] Adhesive based on a polymer having n-butyl acrylate and methyl methacrylate

[0444] Charge 244.3 g of deionized water and 27.3 g of a polystyrene seed dispersion (33 wt%, particle size: 30 nm) into a reactor equipped with a stirrer, a temperature controller, a nitrogen inlet, and multiple injection possibilities. Purge the reaction mixture with nitrogen and heat it to 85 °C. At 85 °C, add 5.0 g of Feed 2. After 5 min, add Feed 1 and Feed 2 over 180 min.

[0445] - Feed 1: 400.5 g of deionized water, 18.5 g of Dowfax 2A1, 20.8 g of Lutensol TO 82, 6.9 g of acrylic acid, 13.9 g of acrylamide (50 wt% aqueous solution), 349.0 g of methyl methacrylate, 335.0 g of n-butyl acrylate.

[0446] - Feed 2: 19.8 g of an aqueous solution of sodium persulfate (7 wt%). Carry out post-polymerization of the reaction mixture at 85 °C for 30 min.

[0447] Then add Feed 3 and Feed 4 over 60 min.

[0448] - Feed 3: 6.9 g of an aqueous solution of tert-butyl hydroperoxide (10 wt%).

[0449] - Feed 4: 6.2 g of an aqueous solution of Rongalit C (10 wt%).

[0450] Then cool the reaction mixture to ambient temperature and neutralize it with sodium hydroxide to pH 8 - 9.

[0451] Tg (of the dried dispersion): 18 °C

[0452] Average particle size: 138 nm

[0453] Solid content: 48.8 wt%

[0454] Example E3 of the present invention

[0455] Adhesive based on a polymer having cyclopentyl methacrylate, n-butyl acrylate, and methyl methacrylate

[0456] Prepare an emulsion by mixing 238.7 g of deionized water, 7.3 g of Emulsifier 1, 22.0 g of Emulsifier 2, and the corresponding amounts of monomers given in the following table:

[0457] E3 Composition Methyl methacrylate [wt%] 2.7 n-Butyl acrylate [wt%] 52.0 Cyclopentyl methacrylate [wt%] 42.5 Acrylic acid [wt%] 1.3 Acrylamide [wt%] 1.5

[0458] The initiator solution was prepared by dissolving 0.7 g of sodium persulfate in 8.8 g of deionized water.

[0459] The oxidation solution O was prepared by dissolving 0.3 g of tert-butyl hydroperoxide in 3 g of deionized water.

[0460] The reduction solution R was prepared by dissolving 0.45 g of sodium sulfite in 3.6 g of deionized water mixed with 0.2 g of acetone.

[0461] 166 g of deionized water and 5.8 g of seed latex were charged into a reaction vessel equipped with a stirrer and three separate feed lines, and the vessel was preheated to 95 °C. After reaching a temperature of 95 °C, the emulsion was fed into the reaction vessel over a period of 165 minutes while maintaining 95 °C. Simultaneously with the start of the emulsion, the initiator solution was fed into the reaction vessel via a separate feed line over a period of 165 minutes. After the addition of the emulsion and the initiator solution was completed, stirring was continued at 95 °C for an additional 15 minutes. Thereafter, the oxidation solution O and the reduction solution R were fed into the reaction vessel in parallel via separate feed lines over a period of 60 minutes at 95 °C. After the addition of the oxidation solution and the reduction solution was completed, the vessel was cooled to room temperature and 7.3 g of sodium hydroxide solution (10% wt 水溶液 ) was added.

[0462] Emulsifier 1: 45 wt% aqueous solution of C12-alkyl diphenyl ether disulfonate

[0463] Emulsifier 2: 20 wt% aqueous solution of ethoxylated isoc13 alcohol with 8 EO

[0464] Seed latex: Polystyrene latex with a solids content of 33 wt% and a diameter of 30 nm

[0465] Tg (dried dispersion): -1.3 °C

[0466] Average particle size: 196 nm

[0467] Solids content: 49.2 wt%

[0468] Example E4 of the present invention

[0469] An emulsion was prepared for the binder based on a polymer having cyclopentyl methacrylate, n-butyl acrylate, 2-ethylhexyl acrylate and styrene by mixing 209 g of deionized water, 39.3 g of emulsifier 3 and the corresponding amounts of monomers given in the table below:

[0470] E4 Composition n-Butyl acrylate [wt%] 32.5 2-Ethylhexyl acrylate [wt%] 13.0 Cyclopentyl methacrylate [wt%] 45.0 Styrene [wt%] 7.0 Acrylic acid [wt%] 1.2 Vinyltriethoxysilane [wt%] 0.8 2-Acrylamido-2-methylpropanesulfonic acid [wt%] 0.5

[0471] The initiator solution was prepared by dissolving 2.2 g of sodium persulfate in 29.2 g of deionized water.

[0472] The oxidation solution O was prepared by dissolving 1.7 g of tert-butyl hydroperoxide in 14.8 g of deionized water.

[0473] The reduction solution R was prepared by dissolving 1.5 g of sodium sulfite in 11.7 g of deionized water mixed with 0.7 g of acetone.

[0474] 163 g of deionized water and 9.2 g of seed latex were charged into a reaction vessel equipped with a stirrer and three separate feed lines, and the vessel was preheated to 85 °C. After reaching the temperature of 85 °C, the emulsion was fed into the reaction vessel over a period of 150 minutes while maintaining 85 °C. Simultaneously with the start of the emulsion, the initiator solution was fed into the reaction vessel via a separate feed line over a period of 180 minutes. After the addition of the emulsion and the initiator solution was completed, stirring was continued at 85 °C for an additional 30 minutes. Thereafter, the oxidation solution O and the reduction solution R were fed into the reaction vessel in parallel via separate feed lines over a period of 120 minutes at 85 °C. After the addition of the oxidation solution and the reduction solution was completed, the vessel was cooled to room temperature and 29.2 g of sodium hydroxide solution (10% wt 水溶液 ) was added.

[0475] Emulsifier 3: 27% by weight aqueous solution of sodium lauryl ether sulfate

[0476] Seed latex: Polystyrene latex having a solids content of 33 wt% and a diameter of 30 nm

[0477] Tg (of the dried dispersion): 5 °C

[0478] Average particle size: 159 nm

[0479] Solids content: 50.7 wt%

[0480] Comparative Example C3

[0481] Adhesive based on a polymer of methyl methacrylate and n-butyl acrylate

[0482] An emulsion was prepared by mixing 238.7 g of deionized water, 7.3 g of emulsifier 1, 22.0 g of emulsifier 2, and the corresponding amounts of monomers given in the following table:

[0483] C3 Composition Methyl methacrylate [wt%] 41.2 n-Butyl acrylate [wt%] 56.0 Acrylic acid [wt%] 1.3 Acrylamide [wt%] 1.5

[0484] The initiator solution was prepared by dissolving 0.7 g of sodium persulfate in 8.8 g of deionized water.

[0485] The oxidation solution O was prepared by dissolving 0.3 g of tert-butyl hydroperoxide in 3 g of deionized water.

[0486] The reduction solution R was prepared by dissolving 0.45 g of sodium sulfite in 3.6 g of deionized water mixed with 0.2 g of acetone.

[0487] 166 g of deionized water and 5.8 g of seed latex were charged into a reaction vessel equipped with a stirrer and three separate feed lines, and the vessel was preheated to 95 °C. After reaching the temperature of 95 °C, the emulsion was fed into the reaction vessel over a period of 165 minutes while maintaining 95 °C. Simultaneously with the start of the emulsion, the initiator solution was fed into the reaction vessel over a period of 165 minutes via a separate feed line. After the addition of the emulsion and the initiator solution was completed, stirring was continued at 95 °C for an additional 15 minutes. Thereafter, the oxidation solution O and the reduction solution R were fed into the reaction vessel in parallel via separate feed lines over a period of 60 minutes at 95 °C. After the addition of the oxidation solution and the reduction solution was completed, the vessel was cooled to room temperature and 7.3 g of sodium hydroxide solution (10% wt 水溶液 ) was added.

[0488] Emulsifier 1: 45 wt% aqueous solution of C12-alkyl diphenyl ether disulfonate

[0489] Emulsifier 2: 20 wt% aqueous solution of ethoxylated isoc13 alcohol with 8 EO

[0490] Seed latex: Polystyrene latex with a solids content of 33 wt% and a diameter of 30 nm

[0491] Tg (dried dispersion): 8 °C

[0492] Average particle size: 193 nm

[0493] Solids content: 52.5 wt%

[0494] Comparative Example C4

[0495] Adhesive based on a polymer having styrene, n-butyl acrylate and 2-ethylhexyl acrylate

[0496] An emulsion was prepared by mixing 209 g of deionized water, 39.3 g of emulsifier 3 and the corresponding amounts of monomers given in the following table:

[0497] C4 Composition n-Butyl acrylate [wt%] 39.8 2-Ethylhexyl acrylate [wt%] 15.7 Styrene [wt%] 42.0 Acrylic acid [wt%] 1.2 Vinyltriethoxysilane [wt%] 0.8 2-Acrylamido-2-methylpropanesulfonic acid [wt%] 0.5

[0498] The initiator solution was prepared by dissolving 2.2 g of sodium persulfate in 29.2 g of deionized water.

[0499] An oxidation solution O was prepared by dissolving 1.7 g of tert-butyl hydroperoxide in 14.8 g of deionized water.

[0500] A reduction solution R was prepared by dissolving 1.5 g of sodium sulfite in 11.7 g of deionized water mixed with 0.7 g of acetone.

[0501] 163 g of deionized water and 9.2 g of seed latex were charged into a reaction vessel equipped with a stirrer and three separate feed lines, and the vessel was preheated to 85 °C. After reaching the temperature of 85 °C, the emulsion was fed into the reaction vessel over a period of 150 minutes while maintaining 85 °C. Simultaneously with the start of the emulsion, an initiator solution was fed into the reaction vessel over a period of 180 minutes via a separate feed line. After the addition of the emulsion and the initiator solution was completed, stirring was continued at 85 °C for an additional 30 minutes. Thereafter, the oxidation solution O and the reduction solution R were fed into the reaction vessel in parallel via separate feed lines over a period of 120 minutes at 85 °C. After the addition of the oxidation solution and the reduction solution was completed, the vessel was cooled to room temperature and 29.2 g of sodium hydroxide solution (10% wt 水溶液 ) was added.

[0502] Emulsifier 3: 27% by weight aqueous solution of sodium lauryl ether sulfate

[0503] Seed latex: Polystyrene latex having a solids content of 33 wt% and a diameter of 30 nm

[0504] Tg (dried dispersion): 8 °C

[0505] Average particle size: 165 nm

[0506] Solids content: 51.8 wt%

[0507] 4.2 Formulation examples

[0508] Example E5 of the present invention

[0509] Formulation of a semi-gloss paint having the binder from Example E1

[0510] Mix 200.0 g of Kronos 4311 pigment with 15.0 g of water. Add 1.0 g of AMP-95 neutralizer (Angus Chemical Company), 1.0 g of BYK-022 antifoaming agent (BYK), 10.0 g of Tamol 731A dispersant (Dow) and 3.0 g of Hydropalat WE 3320 wetting agent (BASF) at low stirring speed. Add 1.5 g of Attagel 50 (BASF), 25.0 g of Minex 10 (Sibelco) filler, 125.0 g of Kronos 4311 pigment, 2.0 g of Proxel AQ, 20.0 g of Aquaflow NHS-310 (Ashland) nonionic associative thickener and 100.1 g of water at high stirring speed and mix for 30 min. Filter the mixture through a 400 μm filter and then add it to a combination of 502.0 g of the binder from Example E1, 25.0 g of Ropaque Ultra E polymer pigment (Dow), 1.5 g of Tego Foamex 810 antifoaming agent (Evonik) and stir for 5 min. Add 11.0 g of Texanol coalescent (Eastman) and stir for 5 min. Then add 3.0 g of Polyphase 663 fungicide (Troy) and 1.0 g of Rheolate CVS10 nonionic associative thickener (Elementis) and mix for 5 min. Finally, add 1.5 g of Acrysol RM 895 nonionic associative thickener (Dow) and 5.4 g of water and stir the mixture at medium speed for 30 min.

[0511] Example E6 of the present invention

[0512] Formulation of a semi-gloss paint having the binder from Example E2

[0513] Mix 200.0 g of Kronos 4311 pigment with 15.0 g of water. Add 1.75 g of AMP-95 neutralizer (Angus Chemical Company), 5.0 g of propylene glycol (Univar), 2.0 g of Foamstar 2420 defoamer (BASF), 10.0 g of Tamol 165A dispersant (Dow), and 3.0 g of Hydropalat WE 3320 wetting agent (BASF) at low stirring speed. Add 1.5 g of Attagel 50 (BASF), 25.0 g of Minex 10 (Sibelco) filler, 125.0 g of Kronos 4311 pigment, 101.4 g of water, and 20.0 g of Aquaflow NHS-310 (Ashland) nonionic associative thickener at high stirring speed and mix for 30 min. Filter the mixture through a 400 μm filter and then add it to a combination of 496.8 g of the binder from Example E2, 25.0 g of RopaqueUltra E polymeric pigment (Dow), and 2.0 g of Foamstar 2420 defoamer (BASF) and stir for 5 min. Add 9.0 g of Texanol coalescent (Eastman) and 8.4 g of Optifilm 400 coalescent (Eastman) and mix for 5 min. Then add 2.0 g of Proxel AQ biocide (Lonza), 3.0 g of Polyphase 663 fungicide (Troy), and 2.5 g of Rheolate CVS10 nonionic associative thickener (Elementis) and mix for 5 min. Finally, add 1.5 g of Acrysol RM 895 nonionic associative thickener (Dow) and stir the mixture at medium speed for 30 min.

[0514] Comparative Example C5

[0515] Formulation of a semi-gloss paint having the binder from Example C1

[0516] Mix 200.0 g of Kronos 4311 pigment with 15.0 g of water. Add 1.0 g of AMP-95 neutralizer (Angus Chemical Company), 1.0 g of BYK-022 antifoaming agent (BYK), 10.0 g of Tamol 731A dispersant (Dow) and 3.0 g of Hydropalat WE 3320 wetting agent (BASF) at low stirring speed. Add 1.5 g of Attagel 50 (BASF), 25.0 g of Minex 10 (Sibelco) filler, 125.0 g of Kronos 4311 pigment, 2.0 g of Proxel AQ, 20.0 g of Aquaflow NHS-310 (Ashland) nonionic associative thickener and 98.0 g of water at high stirring speed and mix for 30 min. Filter the mixture through a 400 μm filter and then add it to a combination of 500.0 g of the binder from Example C1, 25.0 g of Ropaque Ultra E polymer pigment (Dow), 1.5 g of Tego Foamex 810 antifoaming agent (Evonik) and stir for 5 min. Add 12.0 g of Texanol coalescent (Eastman) and mix for 5 min. Then add 3.0 g of Polyphase 663 fungicide (Troy) and 1.0 g of Rheolate CVS10 nonionic associative thickener (Elementis) and mix for 5 min. Finally, add 1.5 g of Acrysol RM 895 nonionic associative thickener (Dow) and 4.3 g of water and stir the mixture at medium speed for 30 min.

[0517] Comparative Example C6

[0518] Formulation of a semi-gloss paint having the binder from Example C2

[0519] Mix 200.0 g of Kronos 4311 pigment with 15.0 g of water. Add 1.75 g of AMP-95 neutralizer (Angus Chemical Company), 5.0 g of propylene glycol (Univar), 2.0 g of Foamstar 2420 antifoaming agent (BASF), 10.0 g of Tamol 165A dispersant (Dow) and 3.0 g of Hydropalat WE 3320 wetting agent (BASF) at low stirring speed. Add 1.5 g of Attagel 50 (BASF), 25.0 g of Minex 10 (Sibelco) filler, 125.0 g of Kronos 4311 pigment, 109.0 g of water and 20.0 g of Aquaflow NHS-310 (Ashland) nonionic associative thickener at high stirring speed and mix for 30 min. Filter the mixture through a 400 μm filter and then add it to a combination of 495.8 g of the binder from Example C2, 25.0 g of Ropaque Ultra E polymer pigment (Dow) and 2.0 g of Foamstar 2420 antifoaming agent (BASF) and stir for 5 min. Add 9.0 g of Texanol coalescent (Eastman) and 5.8 g of Optifilm 400 coalescent (Eastman) and mix for 5 min. Then add 2.0 g of Proxel AQ biocide (Lonza), 3.0 g of Polyphase 663 fungicide (Troy) and 4.0 g of Rheolate CVS10 nonionic associative thickener (Elementis) and mix for 5 min. Finally, add 2.5 g of Acrysol RM 895 nonionic associative thickener (Dow) and stir the mixture at medium speed for 30 min.

[0520] Example E7 of the present invention

[0521] Formulation of a paint having the binder from Example E3

[0522]

[0523]

[0524] Comparative Example C7

[0525] Formulation of a paint having the binder from Example C5

[0526]

[0527] Example E8 of the present invention

[0528] Formulation of a paint having the binder from Example E4

[0529]

[0530]

[0531] Comparative Example C8

[0532] Formulation of a paint having the binder from Example C4

[0533]

[0534] 4.3 Application properties

[0535] The following application properties were determined.

[0536] Gloss:[[]]

[0537] Coating films were prepared on a Leneta 3B black and white sealed drawdown card using a 3 - mil drawdown bar. The films were dried at room temperature for 24 hours. The gloss was measured with a gloss meter at angles of 20°, 60° and 80° respectively. The results are as follows:

[0538]

[0539] Compared with C6, the gloss of E6 is increased

[0540] Low - shear viscosity:[[]]

[0541] Seven days after preparation, the low - shear viscosity was measured according to ASTM D562. The results are as follows:

[0542]

[0543] High - shear viscosity:[[]]

[0544] Seven days after preparation, the high - shear viscosity was measured according to ASTM D4287. The results are as follows:

[0545]

[0546] Compared with C6, the thickening efficiency of E6 is increased

[0547] Opacity:[[]]

[0548] Coating films were prepared on a Leneta 3B black and white sealed drawdown card using a 3 - mil drawdown bar. The films were dried at room temperature for 24 hours. The opacity was determined by spectrophotometry as the ratio of the reflected light of the dried coating on the black and white parts of the Leneta card. The opacity indicates the ability of the coating to cover a black surface. The results are as follows:

[0549]

[0550] Dry alkyd adhesion:

[0551] The dry alkyd adhesion is measured according to ASTM D3359. The evaluation is carried out after 7 days. The dry alkyd adhesion is rated on a scale of 0 to 5, where mark 0 = complete removal of the film and mark 5 = no removal of the film. The results are as follows:

[0552]

[0553] Mark 0 = complete removal of the film, mark 5 = no removal of the film

[0554] Compared with C6, the dry alkyd adhesion of E6 is improved, and compared with C5, the dry alkyd adhesion of E5 is improved.

[0555] Anti-blocking property:

[0556] The anti-blocking properties of E5 and C5 are measured at room temperature according to ASTM D4946. The evaluation is carried out after 7 days. The anti-blocking property is rated on a scale of 0 to 10, where mark 1 is equal to greater than 90% sealing, and mark 10 is equal to non-sticky.

[0557] The results are as follows: E5: 9, C5: 9.

[0558] For E5 and C5, the anti-blocking property is comparable.

[0559] Soil removability:

[0560] The soil removability is measured according to ASTM D4828. The results for coatings from E5 and E6 for pencil, lipstick, crayon, ballpoint pen, red wine, ketchup, coffee, mustard are comparable to those from coatings of C5 and C6 (visual inspection).

[0561] Dust accumulation property:

[0562] The glaze of the yellow pine wood surface is scrubbed with water and dried overnight. The substrate is divided into multiple parts according to the number of samples to be tested. Using an appropriate brush, the test paint sample is applied at the natural coating rate. The coatings are cured at room temperature for 4 hours and 24 hours respectively. Then, half of the coated area is covered with 2 inches of dry soil (Arizona soil or Carpet soil). The panel is allowed to stand for 15 minutes, then tilted vertically and tapped to dislodge the soil. The dirty areas of each sample are gently brushed (15 light swipes).

[0563] For E5, C5, E6, and C6, the dust accumulation property is comparable (visual evaluation).

[0564] Wet scrub resistance:

[0565] The wet scrub resistance (WSR) of the prepared latex paint was tested by the non-woven pad method according to ISO 11998. The WSR was evaluated based on the weight loss per unit area caused by abrasion and was calculated back to the average thickness loss given in μm.

[0566] E7 C7 E8 C8 Wear [μm] 5 6 15 16

[0567] For E7, C7 and E8, C8, the WSW is comparable.

[0568] Spreading rate:

[0569] Opacity (and accordingly hiding power) was quantified by spreading rate measurements. These measurements were carried out by applying different film thicknesses (e.g., 150, 200, 220, and 250 μm wet) to a specified contrast paper, such as Leneta foil with black and white areas, using a drawdown bar (i.e., a doctor blade), and then measuring the contrast. Subsequently, these values were interpolated to yield the so-called spreading rate, which is the reciprocal of the volume of paint per area required to cover the substrate at a given contrast (e.g., 98% or 99.5%) according to ISO DIN 13300 [m 2 / L] (the reciprocal of the film thickness).

[0570] E7 C7 E8 C8 <![CDATA[Spreading rate at 98% contrast [m 2 / L]]]> 7.4 6.2 7.7 7.1

[0571] The spreading rate of E7 is increased compared to C7, and the spreading rate of E8 is increased compared to C8.

Claims

1. An aqueous polymer latex of a film-forming copolymer obtainable by aqueous emulsion polymerization of ethylenically unsaturated monomers M, said ethylenically unsaturated monomers M comprising i. at least one monomer M1 in an amount of 5% to 70% by weight based on the total amount of monomers M, selected from cyclopentyl acrylate, cyclopentyl methacrylate, and mixtures thereof; ii. at least one monomer M2 in an amount of 20% to 90% by weight based on the total amount of monomers M, selected from C2-C 20 -alkyl esters of acrylic acid and C5-C 20 -alkyl esters of methacrylic acid, other than tert-butyl acrylate, and mixtures thereof; iii. one or more monomers M3 in an amount of 0% to 40% by weight based on the total amount of monomers M, selected from tert-butyl acrylate, C1-C4-alkyl esters of methacrylic acid, cyclohexyl methacrylate, isobornyl methacrylate, and monovinyl aromatic monomers, and mixtures thereof; wherein the total amount of monomers M1 and M3 is in the range of 5% to 70% by weight based on the total amount of ethylenically unsaturated monomers M, and wherein the total amount of monomers M1, M2, and M3 is at least 85% by weight based on the total amount of ethylenically unsaturated monomers M.

2. The aqueous polymer latex according to claim 1, wherein The monomer M1 is cyclopentyl methacrylate.

3. The aqueous polymer latex according to any one of the preceding claims, wherein In these monomers M1, at least the carbon atoms of the cyclopentyl group are of biological origin.

4. The aqueous polymer latex according to any one of the preceding claims, wherein These monomers M2 contain isobutyl acrylate.

5. The aqueous polymer latex according to claim 4, wherein At least the carbon atoms of the isobutyl group of isobutyl acrylate are of biological origin.

6. The aqueous polymer latex according to any one of claims 4 and 5, wherein The amount of isobutyl acrylate is in the range of 20% to 80% by weight based on the total amount of monomers M.

7. The aqueous polymer latex according to any one of the preceding claims, wherein The monomer M3 contains methyl methacrylate or is methyl methacrylate, or the monomer M3 contains styrene or is styrene.

8. The aqueous polymer latex according to any one of the preceding claims, wherein These monomers M further contain at least one monomer M4 selected from monounsaturated monomers having an acidic group.

9. The aqueous polymer latex according to claim 8, wherein These monomers M4 are selected from acrylic acid, methacrylic acid, itaconic acid, and combinations thereof.

10. The aqueous polymer latex according to any one of the preceding claims, wherein These monomers M further contain at least one monounsaturated nonionic monomer M5 that has a solubility of at least 60 g / L in deionized water at 20 °C and 1 bar.

11. The aqueous polymer latex according to any one of the preceding claims, wherein These monomers M consist of: i. cyclopentyl methacrylate as monomer M1 in an amount of 5% to 70% by weight based on the total amount of monomers M; ii. at least one monomer M2 in an amount of 20% to 90% by weight based on the total amount of monomers M, which contains isobutyl acrylate or is isobutyl acrylate, or which contains n-butyl acrylate or is n-butyl acrylate; iii. at least one monomer M3 in an amount of 0% to 40% by weight based on the total amount of monomers M, which is selected from styrene, methyl methacrylate, and combinations thereof; iv. one or more monounsaturated monomers M4 in an amount of 0.05% to 5% by weight based on the total amount of these monomers M, which are selected from monounsaturated monomers having an acidic group; v. one or more nonionic monomers M5 in an amount of 0% to 9.95% by weight based on the total weight of these monomers M, which have a solubility of at least 60 g / L in deionized water at 20 °C and 1 bar.

12. The aqueous polymer latex according to any one of the preceding claims, wherein, The polymer particles contain a polymer phase that has a glass transition temperature Tg in the range of -25 °C to +40 °C.

13. A method for producing an aqueous polymer latex according to any one of the preceding claims, the method comprising carrying out an aqueous emulsion polymerization of monomer M.

14. Use of the aqueous polymer latex according to any one of claims 1 to 12 as an adhesive in an aqueous coating composition.

15. An aqueous coating composition comprising a) an adhesive polymer in the form of an aqueous polymer latex according to any one of claims 1 to 12; and b) at least one additional component which is conventionally used in an aqueous coating composition and is not an adhesive.

16. The coating composition according to claim 15, which is a latex paint, in particular a latex paint for architectural coatings, a wood coating or a wood staining composition or a latex paint for interior coatings.

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