Process for preparing an aqueous polymer dispersion

Abstract

A method for preparing an aqueous polymer dispersion includes: performing free radical-initiated emulsion polymerization in an aqueous medium in the presence of at least one vinyl polymer A to obtain a polymer B comprising a vinyl polymer phase B1 having a glass transition temperature of -20°C to +15°C and a vinyl polymer phase B2 having a glass transition temperature of +50°C to +110°C, provided that the glass transition temperature difference between polymer B1 and polymer B2 is at least 40°C, wherein the weight ratio of polymer B1 to polymer B2 is 80:10 to 10:20, and wherein the at least one polymer A is Obtained by a method comprising the following steps: a free radical-initiated bulk or solution polymerization of the following substances: 5 wt% to 25 wt% of at least one carboxylic acid-functionalized olefinic unsaturated monomer A1, and 75 wt% to 95 wt% of at least one olefinic unsaturated monomer A2 different from monomer A1, wherein the amounts are given relative to the total weight of monomers charged in the polymerization for preparing the vinyl polymer A, wherein the weight-average molecular weight of polymer A is lower than that of polymer B, and wherein the weight ratio of polymer A to polymer B is 10:90 to 40:60.

Description

[0001] This invention relates to the field of aqueous acrylic polymer dispersions that can be used to prepare coatings, particularly coatings for industrial applications. Specifically, this invention relates to a method for preparing an aqueous adhesive composition comprising acrylic polymer particles dispersed in an aqueous medium. The method comprises preparing polymer B by radical-initiated emulsion polymerization in an aqueous medium in the presence of at least one vinyl polymer A with a weight-average molecular weight lower than that of vinyl polymer B.

[0002] In the coatings industry, there is a ongoing need for coating compositions containing a limited amount of coalescing agent that produce coatings with good resistance to a variety of chemicals and exhibit good mechanical properties, such as anti-blocking properties, pencil hardness, and / or König hardness. (hardness). This particular combination is challenging. The problem with existing one-component waterborne acrylic coating compositions is that, unless a high glass transition temperature (T) is applied, they are difficult to apply. g The adhesive is crucial; otherwise, these compositions typically do not combine good chemical resistance (e.g., water resistance, ethanol resistance, red wine resistance, coffee resistance, mustard resistance, and / or onion resistance) and good mechanical properties (e.g., anti-blocking properties, pencil hardness, and / or König hardness) in the resulting coating. High T g Adhesives require high levels of coalescing agents, resulting in high VOC (volatile organic compound) levels and potential health and flammability risks. For most applications, permissible VOC levels are limited. VOCs can pose health, safety, or environmental hazards and may need to be reduced or removed from coating systems. For example, for industrial applications such as furniture coatings, the permissible VOC level in Europe, according to EU Directive 2004 / 42 / EC, is below 130 g / L.

[0003] Furthermore, the mechanical properties, particularly coating hardness, of single-component waterborne acrylic coating systems tend to be inferior to those of polyurethane or two-component acrylic coating systems. However, polyurethane is too expensive for certain applications.

[0004] Two-component acrylic coating systems comprise a first component and a second component, each of which is separate and distinct from the others. The first component contains an acrylic polymer, and the second component contains a crosslinking agent, such as an isocyanate. Two-component acrylic coating systems are typically used when high levels of chemical resistance are required. However, such systems utilize crosslinking agents like isocyanates, which are undesirable from a health, safety, and environmental perspective. For example, isocyanates are known to trigger allergic reactions. Furthermore, two-component coating systems have a limited pot life. Finally, the need for crosslinking agents makes such adhesive systems more expensive.

[0005] Another challenge is that the chemical resistance of coating compositions may decrease when matte and / or tinted. For glossy clear coatings, there are one-component waterborne acrylic coating systems that impart good chemical resistance. However, waterborne acrylic adhesives that provide good chemical resistance in clear coatings may exhibit poorer chemical resistance in matte and / or tinted coatings.

[0006] Surprisingly, we have now discovered that the combination of a vinyl polymer B with two phases (B1 and B2) having different glass transition temperatures and an acid-functionalized vinyl polymer A with a lower weight-average molecular weight than vinyl polymer B allows for excellent chemical resistance, particularly water resistance, ethanol resistance, and coffee resistance, and preferably also red wine resistance, mustard resistance, and onion resistance, in formulations with good mechanical properties, particularly anti-blocking properties, pencil hardness, and König hardness, in a unique combination where the A:B ratio, the B1:B2 ratio, and the T of A are all suitable for the application of these properties. g B1's T g B2 of T g And B1's T g T with B2 g T between g Differences are as defined in this article.

[0007] Using the method of the present invention, an aqueous polymer dispersion with low VOC can be prepared, which can be used to prepare a crack-free membrane having at least good chemical resistance, particularly good water resistance, ethanol resistance and coffee resistance, preferably at least good red wine resistance, mustard resistance and onion resistance, as well as good mechanical properties, particularly anti-blocking properties, pencil hardness and König hardness, and at the same time, the decrease in water resistance, ethanol resistance and coffee resistance, preferably red wine resistance, mustard resistance and onion resistance, in colored and / or matte coating formulations is minimal or at least acceptable.

[0008] According to the present invention, a method for preparing an aqueous polymer dispersion comprising at least three vinyl polymer phases is provided, the method comprising:

[0009] Free radical-initiated emulsion polymerization is carried out in an aqueous medium in the presence of at least one vinyl polymer A to form polymer B comprising a vinyl polymer phase B1 with a glass transition temperature of -20°C to +15°C and a vinyl polymer phase B2 with a glass transition temperature of +50°C to +110°C, provided that the glass transition temperature difference between polymer B1 and polymer B2 is at least 40°C.

[0010] in

[0011] The weight ratio of polymer B1 to polymer B2 is 80:10 to 10:20.

[0012] The at least one polymer A is obtained by a method comprising the following steps:

[0013] The following substances undergo free radical-initiated bulk or solution polymerization:

[0014] 5% to 25% by weight of at least one carboxylic acid-functionalized olefinic unsaturated monomer A1, and

[0015] 75% to 95% by weight of at least one olefinic unsaturated monomer A2, which is different from monomer A1.

[0016] The amount mentioned is given relative to the total weight of monomers charged in the polymerization process for preparing vinyl polymer A.

[0017] The glass transition temperature of the at least one vinyl polymer A is between 40°C and 150°C.

[0018] The weight-average molecular weight of the at least one polymer A is from 1000 g / mol to 70000 g / mol.

[0019] The weight-average molecular weight of polymer A is lower than that of polymer B, and

[0020] The weight ratio of polymer A to polymer B is from 10:90 to 40:60.

[0021] WO2018015169 describes a polymer dispersion made from a polymer 2 prepared in the presence of polymer 1, having a Hansch parameter ≥2.8 and a Tg of at least 20°C, wherein polymer 1 contains 3% to 5% by weight of acidic monomers with a Hansch parameter >1.35. This polymer 1 can be prepared via bulk polymerization, solvent polymerization, or emulsion polymerization. This patent publication teaches the use of these polymers for stain-resistant coatings. EP1333047 describes an aqueous ink binder comprising a first polymer and a second polymer prepared in the presence of the first polymer. The first polymer contains 15% to 75% by weight of acidic monomers, has a low molecular weight, a Tg greater than 70°C, and a Hansch parameter between 1.3 and 2.1, and is prepared by bulk polymerization or solution polymerization. These binders are used for inks with water resistance and resolvability on printing presses. US4151143 describes the synthesis of a solution or bulk polymer, followed by a dispersion step in water and a second polymerization step in an aqueous environment. This patent describes a 2C drying application, but does not teach how to apply this concept to one-component adhesives for coatings that are stain-resistant and have high mechanical strength. No specific preference is given for the polymer phase.

[0022] We have now surprisingly discovered that, with a single T g Compared to polymer dispersions of polymer phases, by using a second high T g Introducing the polymer phase into the heavier-average molecular weight polymer portion of these adhesives can yield coatings with the same or even reduced amounts of coalescing agent (and thus the same or reduced VOC levels in the coatings), which enhance the anti-blocking properties of the coatings and maintain good chemical resistance even in colored and / or matte coating formulations.

[0023] Surprisingly, it has been found that VOC levels in coating formulations can be kept low while simultaneously achieving crack-free coatings with good mechanical properties, particularly König hardness, pencil hardness, and anti-blocking properties, as well as good chemical resistance, especially resistance to water, ethanol, and coffee, and preferably also resistance to red wine, mustard, and onions. Anti-blocking properties prevent the coatings from sticking together (or adhering). Poor anti-blocking properties cause two contacting coatings to stick together, resulting in tearing or peeling upon separation. High anti-blocking properties avoid potential coating damage when separating two coated surfaces stacked or placed in contact with each other during storage, packaging, and / or shipping.

[0024] The present invention further relates to an aqueous polymer dispersion obtained by the method described above or obtainable by the method described above.

[0025] Therefore, for the purposes of this invention, "aqueous polymer dispersion" means a dispersion of at least polymers A, B1, and B2 in a liquid carrier medium in which water is the main or sole component. The dispersions of this invention are typically in the form of aqueous polymer latex and comprise colloidal dispersed particles in which polymers A, B1, and B2 are present. Other polymers may be present in the aqueous polymer dispersions of this invention. The total amount of polymers A, B1, and B2 in the aqueous polymer dispersions of this invention is based on the solids content of the aqueous polymer dispersion, preferably greater than 60% by weight, more preferably greater than 70% by weight, more preferably greater than 80% by weight, particularly greater than 90% by weight, even more particularly greater than 95% by weight, and most particularly greater than 97% by weight. The solids content is determined by the evaporation of volatile compounds (e.g., water) and optionally solvents, as well as volatile amines present in the aqueous polymer dispersion.

[0026] The aqueous polymer dispersions of the present invention can be advantageously used to obtain target formulations having the following properties as described in the experimental section of the specification: transparent gloss, transparent gloss, colored gloss, and colored gloss.

[0027] 1. VOCs:

[0028] For the target formulations with transparent gloss and transparent smoothness as described in the experimental section of the instructions, the VOC calculated as described herein is preferably ≤130 g / L, more preferably ≤120 g / L, even more preferably ≤110 g / L, and most preferably ≤100 g / L; and

[0029] For the target formulations with colored gloss and colored smooth surfaces as described in the experimental section of the specification, the VOC calculated as described herein is preferably ≤130 g / L, more preferably ≤125 g / L, even more preferably ≤120 g / L, and most preferably ≤100 g / L; and

[0030] 2. Chemical resistance:

[0031] For the target formulations described in the experimental section of the instructions, including those with clear gloss, clear finish, colored gloss, and colored finish, the chemical resistance is as follows:

[0032] (i) When tested according to DIN 68861-1B:2011-01 (further referred to herein as DIN 68861-1B), the resistance to 48% EtOH for 1 hour is rated as 3, 4 or 5, preferably 4 or 5, and most preferably 5; and

[0033] When tested according to DIN 68861-1B, the water resistance after 16 hours is rated as 3, 4, or 5, preferably 4 or 5, with 5 being the most preferred; and

[0034] When tested according to DIN 68861-1B, the coffee tolerance after 16 hours is rated as 3, 4, or 5, preferably 4 or 5, with 5 being the most preferred; and

[0035] When tested according to DIN 68861-1B, the 6-hour mustard resistance is preferably rated as 3, 4, or 5, more preferably 4 or 5, and most preferably 5; and

[0036] When tested according to DIN 68861-1B, the wine resistance for 6 hours is preferably rated as 3, 4, or 5, more preferably 4 or 5, and most preferably 5; and

[0037] When tested according to DIN 68861-1B, the onion resistance after 6 hours is preferably rated as 3, 4, or 5, preferably 4 or 5, and most preferably 5; and

[0038] When tested according to DIN 68861-1B, the cumulative resistance to 48% EtOH (1 hour), water (16 hours), coffee (16 hours), mustard (6 hours), red wine (6 hours), and onion (6 hours) is preferably 18 or higher, more preferably 21 or higher, even more preferably 24 or higher, and most preferably 27 or higher. More preferably, when tested according to DIN 68861-1B, the cumulative resistance to 48% EtOH (1 hour), water (16 hours), coffee (16 hours), mustard (6 hours), red wine (6 hours), and onion (6 hours) is preferably 18 or higher, preferably 21 or higher, even more preferably 24 or higher, and even more preferably 27 or higher, wherein no single tolerance is lower than 3; and / or

[0039] (ii) As determined according to IOS-MAT-0066 version AA-163938-9, dd 17-01-2014, the tolerance to 48% EtOH (1 hour), water (16 hours) and coffee (1 hour) is preferably passed by IKEA R2 grade, i.e. result ≥4;

[0040] as well as

[0041] 3. Mechanical properties:

[0042] For the target formulations described in the experimental section of the instructions, which have transparent gloss, transparent smooth surface, colored gloss, and colored smooth surface, the mechanical properties are as follows:

[0043] The adhesion measured using a load of 1 kg / cm² according to the method described herein was rated as 3, 4, or 5, preferably 4 or 5, and most preferably 5; and

[0044] The adhesion measured using a load of 3 kg / cm² according to the method described herein was rated as 3, 4, or 5, preferably 4 or 5, and most preferably 5; and

[0045] The Koenig hardness, determined by the method described herein using a drying time of 16 hours at 50°C after 24 hours at room temperature, is at least 80 seconds, preferably at least 90 seconds, and most preferably at least 100 seconds; and

[0046] The pencil hardness measured according to the method described herein is preferably at least 2B, more preferably at least B.

[0047] For any range given herein, all upper and lower boundaries are included within the given range unless otherwise specified. Therefore, when we say from x to y, we mean including x and y, as well as all intermediate values.

[0048] Polymer A

[0049] The carboxylic acid-functionalized olefinic unsaturated monomer A1 is preferably selected from the group consisting of: acrylic acid, methacrylic acid, β-carboxyethyl acrylate, citraconic acid, crotonic acid, fumaric acid, itaconic acid, monoalkyl esters of itaconic acid (e.g., monomethyl itaconic acid), maleic acid, and potential carboxylic acid-functionalized olefinic unsaturated monomers (e.g., itaconic anhydride or maleic anhydride), and combinations thereof. More preferably, monomer A1 is selected from the group consisting of: acrylic acid, methacrylic acid, itaconic acid, fumaric acid, and mixtures thereof. Most preferably, monomer A1 is methacrylic acid and / or acrylic acid.

[0050] Monomer A2 is an olefinically unsaturated monomer, distinct from monomer A1, and can be copolymerized with monomer A1. Available monomers A2 include acrylates, methacrylates, arylalkylene groups, dienes, vinyl esters, nitriles, olefinically unsaturated halides, and any mixtures thereof. Examples of suitable dienes are 1,3-butadiene and isoprene. Examples of suitable vinyl esters are vinyl acetate. Suitable arylalkylene groups include (optionally substituted with a hydrocarbon group) styrene, and conveniently, the optional hydrocarbon group may be C1. 1-10 Hydrocarbon group, more conveniently C 1-4 Alkyl groups. Suitable arylalkylene monomers may be selected from: styrene, α-methylstyrene, vinyltoluene, tert-butylstyrene, dimethylstyrene and / or mixtures thereof, especially styrene and / or α-methylstyrene. Suitable nitriles are acrylonitrile and methacrylonitrile. Suitable olefinic unsaturated halides are vinyl chloride, vinylidene chloride and vinyl fluoride. The above monomers typically form at least 80% by weight, preferably at least 90% by weight, more preferably at least 92% by weight, more preferably at least 94% by weight and most preferably 100% by weight of the total amount of monomer A2, and thus constitute the principal monomer A2. Preferably, the principal monomer A2 is selected from the group consisting of: acrylates, methacrylates, arylalkylene groups and any mixtures thereof. Preferably, the acrylates or methacrylates include (meth)acrylate hydrocarbon esters, and conveniently, the hydrocarbon moiety may be C10. 1-20 Hydrocarbon group, more conveniently C 1-12 Alkyl groups, most conveniently C10, are used. 1-10 Alkyl, such as C 1-8Alkyl group. Suitable (meth)acrylates may be selected from: methyl (meth)acrylate, ethyl (meth)acrylate, 4-methyl-2-pentyl (meth)acrylate, 2-methylbutyl (meth)acrylate, isoamyl (meth)acrylate, sec-butyl (meth)acrylate, n-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, 2-octyl (meth)acrylate, lauryl (meth)acrylate, isodecanyl (meth)acrylate, cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, and / or mixtures thereof. More preferably, the principal monomer A2 is selected from the group consisting of: methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-butyl methacrylate, n-butyl acrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, styrene, α-methylstyrene, and any mixture thereof. Even more preferably, the principal monomer A2 is styrene, α-methylstyrene, methyl methacrylate, n-butyl acrylate, and / or 2-ethylhexyl acrylate. Even more preferably, the primary monomer A2 is styrene and / or α-methylstyrene.

[0051] Optionally, monomer A2 is used, which is an olefinically unsaturated monomer having functional groups for imparting crosslinkability during the subsequent drying of an aqueous coating formulation comprising an aqueous polymer dispersion. The functional groups for providing crosslinkability are preferably selected from silyl, epoxy, hydroxyl, ketone, and aldehyde groups. Monomer A2 having functional groups for imparting crosslinkability is preferably selected from glycidyl (meth)acrylate, hydroxyalkyl (meth)acrylate (e.g., hydroxyethyl (meth)acrylate), and methyl vinyl ketone, acetoacetoxy esters of hydroxyalkyl (meth)acrylate (e.g., acetoacetoxyethyl (meth)acrylate), and ketone-containing amides (e.g., diacetone acrylamide). The most preferred functional group for providing crosslinkability is a ketone group. In the application of monomer A2 having functional groups for imparting crosslinkability in this invention, the aqueous polymer dispersion is preferably combined with a crosslinking agent (i.e., such that crosslinking occurs, for example, after a coating is formed from the aqueous polymer dispersion). For example, comonomers having hydroxyl functional groups for imparting crosslinkability are used in combination with polyisocyanates or melamine resins, for example, as crosslinking agents, resulting in two-component acrylic coating systems; however, such two-component acrylic coating systems are not preferred. Comonomers having functional groups (including ketone and / or aldehyde functional groups) for imparting crosslinkability are used in combination with polyamines or polyhydrazides, for example, as crosslinking agents. Examples of suitable polyamines are isophorone diamine or polyalkylene imides, such as polyethyleneimine, which are available, for example, from BASF under the trade name... Examples of suitable polyhydrazides are carbodiazid, adipic acid dihydrazides, oxalate dihydrazides, phthalate dihydrazides, and terephthalate dihydrazides. Preferred polyhydrazides are carbodiazid or adipic acid dihydrazides. When the waterborne coating formulation is subsequently dried, the preferred combination of the crosslinking agent and the functional group for imparting crosslinkability is the combination of adipic acid dihydrazide or carbodiazid as a crosslinking agent with at least one ketone group present in monomer A2 having a functional group for imparting crosslinkability. Diacetone acrylamide (DAAM) is a preferred monomer A2 having a ketone functional group, which is used in combination with carbodiazid or adipic acid dihydrazides. Monomer A2 having a functional group for imparting crosslinkability is generally used in an amount of ≤10% by weight, preferably ≤8% by weight, more preferably ≤6% by weight of the total amount of monomer A2. However, in one embodiment of the invention, it is advantageous that the vinyl polymer A is substantially free of, and more advantageously free of, olefinically unsaturated monomers containing crosslinkable groups. It should be noted that monomer A1, particularly (meth)acrylic acid, can also be used as a crosslinkable monomer. For example, (meth)acrylic acid is commonly used as a water-dispersible monomer; however, it can also be used as a crosslinkable monomer. In the context of this invention, such a monomer is considered to be an A1 monomer.

[0052] Monomer A2 is preferably selected from the group consisting of: methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-butyl methacrylate, n-butyl acrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, styrene, α-methylstyrene, and any mixture thereof. Even more preferably, monomer A2 is styrene, α-methylstyrene, methyl methacrylate, n-butyl acrylate, and / or 2-ethylhexyl acrylate. Most preferably, the main monomer A2 is styrene and / or α-methylstyrene.

[0053] The at least one vinyl polymer A comprises:

[0054] 5% to 25% by weight of at least one carboxylic acid-functionalized olefinic unsaturated monomer A1, and

[0055] 75% to 95% by weight of at least one olefinic unsaturated monomer A2, which is different from monomer A1.

[0056] The amounts are given relative to the total weight of monomers charged in the polymerization for preparing vinyl polymer A. Preferably, the total amount of monomers A1 and A2 is 100% by weight, that is, the monomers charged in the polymerization for preparing vinyl polymer A preferably consist of monomers A1 and A2.

[0057] Preferably, the at least one vinyl polymer A comprises:

[0058] 10% to 22.5% by weight of at least one carboxylic acid-functionalized olefinic unsaturated monomer A1, and

[0059] From 77.5% to 90% by weight of at least one olefinically unsaturated monomer A2 different from monomer A1, wherein the amount is given relative to the total weight of monomers charged in the polymerization for preparing vinyl polymer A. Preferably, the total amount of monomers A1 and A2 is 100% by weight, that is, the monomers charged in the polymerization for preparing vinyl polymer A preferably consist of monomers A1 and A2.

[0060] More preferably, the at least one vinyl polymer A comprises:

[0061] 12.5% ​​to 22.5% by weight of at least one carboxylic acid-functionalized olefinic unsaturated monomer A1, and

[0062] From 77.5% to 87.5% by weight, at least one olefinically unsaturated monomer A2 different from monomer A1, wherein the amount is given relative to the total weight of monomers charged in the polymerization for preparing vinyl polymer A. Preferably, the total amount of monomers A1 and A2 is 100% by weight, that is, the monomers charged in the polymerization for preparing vinyl polymer A preferably consist of monomers A1 and A2.

[0063] The weight-average molecular weight of the at least one polymer A is from 1000 g / mol to 70000 g / mol, preferably from 5000 g / mol to 60000 g / mol, more preferably from 7000 g / mol to 50000 g / mol, and most preferably from 10000 g / mol to 40000 g / mol. The molecular weight distribution was determined by SEC and measured at 70°C using three PLgel 10 μm mixed B columns on a Waters Alliance 2695LC system equipped with a Waters 2410DRI detector and a Waters 2996PDA detector. N-methylpyrrolidone (NMP) containing 20% ​​v / v methyl ethyl ketone (MEK) and 10 mmol lithium bromide (LiBr) was used as the eluent at a flow rate of 1 mL / min. The sample was dissolved in the eluent at a concentration of 5 mg polymer / mL solvent. Solubility was determined using a laser pointer after stabilization at room temperature for 24 hours; if any scattering was visible, the sample was first filtered, and 150 μl of sample solution (0.45 μm PTFE filter) was injected. MMD (molecular weight distribution), number-average molecular weight, and weight-average molecular weight results were calculated using narrow-band polystyrene standards ranging from 474 Da to 1,730,000 Da. As used herein, the weight-average molecular weights of polymers A, B1, and B2 were determined using SEC as described above.

[0064] Monomers A1 and A2 are preferably selected such that the glass transition temperature of at least one vinyl polymer A is between 60°C and 140°C, more preferably between 70°C and 130°C. In the case where more than one vinyl polymer A is present in the aqueous dispersion, the weight-average glass transition temperature is used. As used herein, the glass transition temperature is determined by calculation using the Fox equation. Therefore, the Tg in Kelvin of a copolymer having “n” comonomers is... g It is based on the following formula, which is the weight fraction W of each comonomer type and the T of the homopolymer derived from each comonomer. g (In Kelvin) given:

[0065] T g =1 / (∑(W) n / Tg n )

[0066] The glass transition temperature of homopolymers can be found, for example, in the "Polymer Handbook", edited by J. Brandrup and E. Himmergut.

[0067] Monomers A1 and A2 are preferably selected such that the calculated Hansch parameter of polymer A is greater than 1.35, more preferably at least 1.40, and even more preferably at least 1.50. Preferably, the calculated Hansch parameter of polymer A is at most 2.20.

[0068] When more than one vinyl polymer A is present in the aqueous dispersion, the weight-average Hansch parameter is used. The Hansch parameter of the polymer is calculated using the group contribution method. The monomer units forming the polymer are assigned hydrophobic contributions and the hydrophobicity of the polymer. The Hansch parameter is calculated based on the weight average of the monomers present in the monomer mixture used to produce the polymer, as disclosed in Hansch and Fujita, J. Amer. Chem. Soc., 86, 1616-1626 (1964); H. Kubinyi, Methods and Principles of Medicinal Chemistry, Volume 1, R. Mannhold et al., Eds., VCH, Weinheim (1993); C. Hansch and A. Leo, Substituent Constants for Correlation Analysis in Chemistry and Biology, Wiley, New York (1979); and C. Hansch, P. Maloney, T. Fujita, and R. Muir, Nature, 194, 178-180 (1962). High pH Hansch parameters are used. In the context of this invention, the Hansch parameters of the monomer are typically calculated using the software "KOWWIN v1.68" (September 2010), which was developed by the U.S. Environmental Protection Agency (EPA) under the "Estimation Programs Interface Suite". TM Available to the public in "for Microsoft(R) Windows, v4.11"

[2012] , United States Environmental Protection Agency, Washington, DC, USA. This procedure determines the Hansch parameters for monomers A1 and A2 and monomers B1 and B2 in the Hansch parameters used in this document. Since the polymer A used or the aqueous polymer dispersion obtained by the method advantageously has a pH value in the neutral to weakly basic range, it is assumed that the acid-containing monomers are completely deprotonated, and therefore calculations are performed using the salt specified in each case.

[0069]

[0070]

[0071] The at least one vinyl polymer A is prepared by conventional free radical-initiated bulk or solution polymerization known to those skilled in the art. Bulk polymerization is preferably a semi-continuous or continuous process using, for example, a plug flow reactor or a heat pipe reactor. Bulk polymerization of vinyl monomers is described in detail in EP156170, WO82 / 02387, and US4414370. Generally, in a bulk polymerization process, a mixture of two or more vinyl monomers is continuously charged into a reactor zone containing molten vinyl oligomers having the same vinyl monomer ratio as the vinyl monomer mixture. The polymer A prepared by bulk polymerization is preferably made water-dispersible by partial or complete neutralization of the carboxylic acid groups. Suitable neutralizing agents are bases, examples of which include organic bases such as alkylamines (e.g., triethylamine, tributylamine), morpholine, and alkanolamines; and inorganic bases, examples of which include ammonia, NaOH, KOH, and LiOH. Preferably, the base is selected from the group consisting of ammonia, dimethylethanolamine, or mixtures thereof.

[0072] When polymer A is prepared using solution polymerization, polymer A is dissolved in a suitable solvent. Suitable solvents are the coalescing agents described below and / or solvents with a boiling point below 150°C at atmospheric pressure. Preferred solvents are those with a boiling point not exceeding 130°C at atmospheric pressure, more preferably not exceeding 100°C, and most preferably not exceeding 90°C. Preferred solvents are acetone, methyl ethyl ketone, ethanol, isopropanol, ethyl acetate, butyl acetate, and / or toluene. Other suitable solvents will be well known to those skilled in the art. The most preferred solvents are acetone and / or methyl ethyl ketone. In cases where the polymerization temperature exceeds the boiling point of the solvent and / or monomer, polymerization will be carried out under increased pressure. Polymer A prepared by solution polymerization can be dissolved or dispersed in water using an alkali and then used as is. However, it is preferable to remove the solvent used in the polymerization step after dispersing polymer A in water using an alkali. Solvent removal can be carried out by increasing the temperature or decreasing the pressure. A combination of these is preferred. The solvent can be removed after dispersing polymer A and before further use. However, it is contemplated that the solvent can also be removed after polymer A is used in the subsequent steps detailed below.

[0073] To prepare vinyl polymer A, conventional free radical generating initiators can be used. Suitable free radical generating initiators include inorganic peroxides, such as percarbonates; organic peroxides, such as acyl peroxides, including, for example, benzoyl peroxide; alkyl hydroperoxides, such as tert-butyl hydroperoxide and cumene hydroperoxide; dialkyl peroxides, such as di-tert-butyl peroxide; peroxide esters, such as tert-butyl perbenzoate, etc.; mixtures may also be used. Azo-functionalized initiators may also be used. Preferred azo initiators include 2,2'-azobis(2-methylbutyronitrile) and 4,4'-azobis(4-cyanopentanoic acid). The amount of initiator or initiator system used is conventional, for example, in the range of 0.05% to 6% by weight based on the total vinyl monomers used to prepare vinyl polymer A. Preferred initiators include 2,2'-azobis(2-methylbutyronitrile), 4,4'-azobis(4-cyanopentanoic acid), peroxide esters, and mixtures thereof. The molecular weight of vinyl polymer A can be adjusted by the initiator concentration and temperature.

[0074] Vinyl polymer A contains sufficient water-dispersible groups to make it dispersible or partially soluble in an aqueous medium (i.e., at least a portion of the potential ionic carboxylic acid groups of polymer A are deprotonated by neutralizing at least a portion of the carboxylic acid functional groups of polymer A to obtain ionic water-dispersible groups). As used herein, a potential ionic water-dispersible group refers to a group that can be converted into an ionic group under relevant conditions through salt formation. Suitable neutralizing agents are bases, examples of which include organic bases such as alkylamines (e.g., triethylamine, tributylamine), morpholine, and alkanolamines; and inorganic bases, examples of which include ammonia, NaOH, KOH, and LiOH. Preferably, the base is selected from the group consisting of ammonia, dimethylethanolamine, or mixtures thereof. Preferably, neutralization (deprotonation) is performed after the bulk or solution polymerization process for preparing vinyl polymer A, and before, during, or before and during the radical-initiated aqueous emulsion polymerization for preparing polymer B. More preferably, neutralization is performed before performing the radical-initiated aqueous emulsion polymerization for preparing polymer B. Therefore, the method of the present invention preferably further includes at least partially deprotonating a carboxylic acid group to obtain polymer A.

[0075] Preferably, the method further comprises dispersing at least one polymer A in water prior to the free radical-initiated emulsion polymerization of polymer B. The neutralization (deprotonation) and dispersion of polymer A can be carried out sequentially, for example by first adding an alkali to the bulk or solution polymer and then adding water, or by first adding an alkali to the bulk or solution polymer and then adding the composition to water. The neutralization (deprotonation) and dispersion of polymer A can also be carried out simultaneously by adding an alkali and water to the bulk or solution polymer, or by adding the bulk or solution polymer to an aqueous solution of an alkali.

[0076] Preferably, the method of the present invention includes

[0077] A) Prepare at least one vinyl polymer A by a method comprising the following steps:

[0078] The following substances undergo free radical-initiated bulk or solution polymerization:

[0079] 5% to 25% by weight of at least one carboxylic acid-functionalized olefinic unsaturated monomer A1, and

[0080] 75% to 95% by weight of at least one olefinic unsaturated monomer A2, which is different from monomer A1.

[0081] The amounts are given relative to the total weight of monomers charged in the polymerization for preparing vinyl polymer A, and the amounts of monomers A1 and A2 are preferably a total of 100% by weight.

[0082] B) At least partially deprotonating the carboxylic acid group and dispersing polymer A in an aqueous medium to obtain an aqueous dispersion of at least one polymer A, and

[0083] C) A free radical-initiated emulsion polymerization is carried out in the presence of at least one aqueous dispersion of polymer A to form polymer B comprising a vinyl polymer phase B1 with a glass transition temperature of -20°C to +15°C and a vinyl polymer phase B2 with a glass transition temperature of +50°C to +110°C, provided that the glass transition temperature difference between polymer B1 and polymer B2 is at least 40°C.

[0084] The weight ratio of polymer B1 to polymer B2 is 80:10 to 10:20.

[0085] The glass transition temperature of the at least one vinyl polymer A is between 40°C and 150°C.

[0086] The weight-average molecular weight of the at least one polymer A is from 1000 g / mol to 70000 g / mol.

[0087] The weight-average molecular weight of polymer A is lower than that of polymer B, and

[0088] The weight ratio of polymer A to polymer B is from 10:90 to 40:60.

[0089] Polymer B

[0090] Polymer B comprises two polymer phases: a soft vinyl polymer phase B1 with a glass transition temperature of -20°C to +15°C and a hard vinyl polymer phase B2 with a glass transition temperature of +50°C to +110°C.

[0091] The weight ratio of polymer B1 to polymer B2 is 80:10 to 10:20, preferably 70:10 to 10:20, more preferably 60:10 to 10:20, even more preferably 50:10 to 10:18, and most preferably 40:10 to 10:15.

[0092] Polymer B has a higher weight-average molecular weight than polymer A. Polymer B2 may optionally have a lower weight-average molecular weight than polymer A. The weight-average molecular weight of polymer B is preferably at least 100,000 g / mol, thereby the weight-average molecular weight of polymer B2 may optionally be lower than 100,000 g / mol. Preferably, the weight-average molecular weights of polymer phases B1 and B2 in polymer B are not adjusted. Most preferably, the weight-average molecular weight of polymer B1 is at least 100,000 g / mol, and the weight-average molecular weight of polymer B2 is at least 100,000 g / mol.

[0093] Polymer phases B1 and B2 were prepared by conventional free radical-initiated aqueous emulsion polymerization in the presence of polymer A.

[0094] Preferably, polymer phase B1 is prepared by aqueous emulsion polymerization initiated by the free radicals of the following substances in the presence of polymer A:

[0095] 0% to 5% by weight of at least one carboxylic acid-functionalized olefinic unsaturated monomer B1.1, and

[0096] The monomer B1 contains 95% to 100% by weight of at least one olefinically unsaturated monomer B1.2, which is different from monomer B1.1, wherein the amount is given relative to the total weight of monomers charged in the polymerization for preparing the vinyl polymer B1, and wherein the total amount of monomers B1.1 and B1.2 is preferably 100% by weight, i.e., the monomers charged in the polymerization for preparing the polymer phase B1 preferably consist of monomers B1.1 and B1.2. More preferably, in the preparation of polymer B1, the amount of monomer B1.1 is at most 3% by weight, even more preferably at most 2% by weight, and particularly preferably 0% by weight, and correspondingly, the amount of monomer B1.2 is more preferably at least 97% by weight, even more preferably at least 98% by weight, and particularly preferably 100% by weight.

[0097] Preferably, polymer phase B2 is prepared by aqueous emulsion polymerization initiated by the free radicals of the following substances in the presence of polymer A:

[0098] 0% to 5% by weight of at least one carboxylic acid-functionalized olefinic unsaturated monomer B2.1, and

[0099] The polymer contains 95% to 100% by weight of at least one olefinically unsaturated monomer B2.2, different from monomer B2.1, wherein the amount is given relative to the total weight of monomers charged in the polymerization for preparing the vinyl polymer B2, and wherein the total amount of monomers B2.1 and B2.2 is preferably 100% by weight, i.e., the monomers charged in the polymerization for preparing the polymer phase B2 preferably consist of monomers B2.1 and B2.2. More preferably, in the preparation of polymer B2, the amount of monomer B2.1 is at most 3% by weight, even more preferably at most 2% by weight, and particularly preferably 0% by weight, and correspondingly, the amount of monomer B2.2 is more preferably at least 97% by weight, even more preferably at least 98% by weight, and particularly preferably 100% by weight.

[0100] Suitable monomers B1.1 and B2.1 correspond to monomer A1 as described above, and suitable monomers B1.2 and B2.2 correspond to monomer A2 as described above, the difference being that the properties and amounts of these monomers are selected such that polymer B1 obtained from monomers B1.1 and B1.2 has a glass transition temperature of -20°C to +15°C, and polymer B2 obtained from monomers B2.1 and B2.2 has a glass transition temperature of +50°C to +110°C, provided that the glass transition temperature difference between polymer B1 and polymer B2 is at least 40°C.

[0101] The glass transition temperature of the vinyl polymer phase B1 is -20°C to +15°C.

[0102] The glass transition temperature of the vinyl polymer phase B2 is +50°C to +110°C, preferably +55°C to +105°C, and more preferably +60°C to +105°C.

[0103] The glass transition temperature difference between polymer B1 and polymer B2 is at least 40°C, preferably at least 45°C, more preferably at least 50°C, even more preferably at least 55°C, even more preferably at least 60°C, even more preferably at least 65°C, even more preferably at least 70°C, even more preferably at least 75°C. Therefore, the glass transition temperature difference between polymer B2 and polymer B2 is... g T than polymer B1 g The temperature is at least 40°C, preferably at least 45°C, more preferably at least 50°C, even more preferably at least 55°C, even more preferably at least 60°C, even more preferably at least 65°C, even more preferably at least 70°C, even more preferably at least 75°C.

[0104] Monomers B1.2 and B2.2 are olefinically unsaturated monomers, distinct from monomers B1.1 and B2.1, and can be used for copolymerization with monomers B1.1 and B2.1. Useful monomers B1.2 and B2.2 include acrylates, methacrylates, arylalkylene groups, dienes, vinyl esters, nitriles, olefinically unsaturated halides, and any mixtures thereof. Examples of suitable dienes are 1,3-butadiene and isoprene. Examples of suitable vinyl esters are vinyl acetate. Suitable arylalkylene groups include (optionally substituted with a hydrocarbon group) styrene, and conveniently, the optional hydrocarbon group may be C1.2. 1-10 Hydrocarbon group, more conveniently C 1-4 Alkyl groups. Suitable arylalkylene monomers may be selected from: styrene, α-methylstyrene, vinyltoluene, tert-butylstyrene, dimethylstyrene and / or mixtures thereof, especially styrene and / or α-methylstyrene. Suitable nitriles are acrylonitrile and methacrylonitrile. Suitable olefinic unsaturated halides are vinyl chloride, vinylidene chloride and vinyl fluoride. The above monomers generally form at least 80% by weight, preferably at least 90% by weight, more preferably at least 92% by weight, more preferably at least 94% by weight and most preferably 100% by weight of the total amount of monomers B1.2 and B2.2, and thus constitute the main monomers B1.2 and B2.2. Preferably, the main monomers B1.2 and B2.2 are independently selected from the group consisting of: acrylates, methacrylates, arylalkylene groups and any mixtures thereof. Preferably, the acrylates or methacrylates include (meth)acrylate hydrocarbon esters, and conveniently, the hydrocarbon moiety may be C12.2. 1-20 Hydrocarbon group, more conveniently C 1-12 Alkyl groups, most conveniently C10, are used. 1-10 Alkyl, such as C 1-8Alkyl group. Suitable (meth)acrylates may be selected from: methyl (meth)acrylate, ethyl (meth)acrylate, 4-methyl-2-pentyl (meth)acrylate, 2-methylbutyl (meth)acrylate, isoamyl (meth)acrylate, sec-butyl (meth)acrylate, n-butyl (meth)acrylate, tert-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, 2-octyl (meth)acrylate, lauryl (meth)acrylate, isodecanyl (meth)acrylate, cyclohexyl (meth)acrylate and / or mixtures thereof. More preferably, the principal monomers B1.2 and B2.2 are independently selected from the group consisting of: methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-butyl methacrylate, n-butyl acrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, styrene, α-methylstyrene and any mixtures thereof. Even more preferably, the principal monomers B1.2 and B2.2 are independently styrene, methyl methacrylate, n-butyl acrylate, 2-ethylhexyl acrylate, or any mixture thereof. Even more preferably, the principal monomers B1.2 and B2.2 are independently styrene and / or 2-ethylhexyl acrylate.

[0105] Optionally, monomers B1.2 and / or B2.2 are used, which are olefinic unsaturated monomers having functional groups that impart crosslinkability when subsequently drying aqueous coating formulations containing aqueous polymer dispersions. The functional groups providing crosslinkability are preferably selected from silyl, epoxy, hydroxyl, ketone, and aldehyde groups. Monomers B1.2 and / or B2.2 having functional groups for imparting crosslinkability are preferably selected from glycidyl (meth)acrylate, hydroxyalkyl (meth)acrylate (e.g., hydroxyethyl (meth)acrylate), and methyl vinyl ketone, acetoacetoxy esters of hydroxyalkyl (meth)acrylate (e.g., acetoacetoxyethyl (meth)acrylate), and ketone-containing amides (e.g., diacetone acrylamide). The most preferred functional group for providing crosslinkability is a ketone group. In the application of monomers B1.2 and / or B2.2 having functional groups for imparting crosslinkability in this invention, the aqueous polymer dispersion is preferably combined with a crosslinking agent (i.e., such that crosslinking occurs, for example, after a coating is formed from the aqueous polymer dispersion). For example, a comonomer having hydroxyl functional groups for imparting crosslinkability is used in combination with, for example, a polyisocyanate as a crosslinking agent, resulting in a two-component acrylic coating system; however, such a two-component acrylic coating system is not preferred. Comonomers having functional groups for imparting crosslinkability (including ketone and / or aldehyde functional groups) are used in combination with, for example, a polyamine or polyhydrazide as a crosslinking agent. Examples of suitable polyamines are isophorone diamine or polyalkylene imides, such as polyethyleneimine, which are available, for example, from BASF under the trade name... Examples of suitable polyhydrazides are carbodiazid, adipate dihydrazides, oxalate dihydrazides, phthalate dihydrazides, and terephthalate dihydrazides. Preferred polyhydrazides are carbodiazid or adipate dihydrazides. When subsequently drying the waterborne coating formulation, a preferred combination of crosslinking agent and functional group for imparting crosslinkability is a combination of carbodiazid or adipate dihydrazides as crosslinking agents and at least one ketone group present in monomers B1.2 and / or B2.2 having functional groups for imparting crosslinkability. Diacetone acrylamide (DAAM) is a preferred monomer B1.2 and / or preferred monomer B2.2 having ketone functional groups, used in combination with carbodiazid or adipate dihydrazides. Monomer B1.2 having functional groups for imparting crosslinkability and monomer B2.2 having functional groups for imparting crosslinkability are typically used in amounts of ≤10% by weight, preferably ≤8% by weight, more preferably ≤6% by weight, even more preferably ≤4% by weight, and even more preferably ≤2% by weight, of the total weight of monomers incorporated in the preparation of polymer B1 or polymer B2. However, in one embodiment of the invention, polymers B1 and B2 are advantageously substantially free of, and more advantageously free of, olefinically unsaturated monomers containing crosslinkable groups.

[0106] Optional alkylene unsaturated monomers containing at least two non-conjugated alkylene unsaturated double bonds are used as monomers B1.2 and / or B2.2. Examples of these are monomers having two vinyl moieties, monomers having two vinylidene moieties, and monomers having two alkenyl moieties. Particularly advantageous monomers are diesters of diols with α,β-monoalkylene unsaturated monocarboxylic acids, wherein acrylic acid and methacrylic acid are preferred among these α,β-monoalkylene unsaturated monocarboxylic acids. Examples of such monomers having two non-conjugated alkylene unsaturated double bonds are alkylene diacrylates and alkylene dimethacrylates, such as ethylene glycol diacrylate, propane 1,2-diol diacrylate, propane 1,3-diol diacrylate, butane 1,3-diol diacrylate, butane 1,4-diol diacrylate, hexane-1,6-diol diacrylate, and ethylene glycol dimethacrylate, propane 1,2-diol dimethacrylate. Propane 1,3-diol ester, butylene 1,3-dimethacrylate, butylene 1,4-dimethacrylate, hexane-1,6-diol ester, and also divinylbenzene, vinyl methacrylate, vinyl acrylate, allyl methacrylate, allyl acrylate, diallyl maleate, diallyl fumarate, methylenebisacrylamide, cyclopentadienyl acrylate, triallyl cyanurate, and triallyl isocyanurate. Alkenyl unsaturated monomers containing non-conjugated alkene unsaturated double bonds with different reactivity are generally referred to as graft linker monomers. A preferred graft linker monomer is allyl methacrylate. The aforementioned monomers B2.1 and / or B2.2 are generally used in an amount of ≤5% by weight, preferably ≤2% by weight, and more preferably 0% by weight of the total weight of the monomers incorporated in the preparation of polymer B1 or polymer B2.

[0107] Monomers B1.2 and / or B2.2 are preferably independently selected from the group consisting of: methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-butyl methacrylate, n-butyl acrylate, tert-butyl methacrylate, tert-butyl acrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, styrene, α-methylstyrene, and any mixture thereof. Even more preferably, monomers B1.2 and B2.2 are independently styrene, methyl methacrylate, n-butyl acrylate, and / or 2-ethylhexyl acrylate. Even more preferably, monomers B1.2 and B2.2 are independently styrene and / or 2-ethylhexyl acrylate.

[0108] There is no preference regarding whether polymer phase B1 is polymerized first, followed by polymer phase B2, or vice versa. If polymer phase B1 is polymerized first, polymer phase B2 is prepared in the presence of polymer A and polymer B1. If polymer phase B2 is polymerized first, polymer phase B1 is prepared in the presence of polymer A and polymer B2.

[0109] Preferably, polymer B is composed of two polymer phases, B1 and B2.

[0110] The monomer used to prepare the vinyl polymer B1 is preferably selected such that the calculated Hansch parameter is greater than 1.20, more preferably at least 1.40, even more preferably at least 1.60, even more preferably at least 1.80, even more preferably at least 2.0, even more preferably at least 2.20, even more preferably at least 2.40, even more preferably at least 2.60, and even more preferably at least 2.80, and advantageously at most 4.00, more advantageously at most 3.80, more advantageously at most 3.70, and even more advantageously at most 3.60.

[0111] The monomer used to prepare the vinyl polymer B2 is preferably selected such that the calculated Hansch parameter is greater than 1.20, more preferably at least 1.40, even more preferably at least 1.60, even more preferably at least 1.80, even more preferably at least 2.0, even more preferably at least 2.20, even more preferably at least 2.40, even more preferably at least 2.60, and even more preferably at least 2.80, and advantageously at most 4.00, more advantageously at most 3.80, more advantageously at most 3.70, even more advantageously at most 3.60, and even more advantageously at most 3.50.

[0112] Methods for preparing vinyl polymers by free radical-initiated emulsion polymerization in an aqueous medium are known in the art and described, for example, in Handbook Emulsion Polymerization: Theory and Practice, 1975, by DC Blackley (ISBN 978-0-85334-627-2). The preparation of vinyl polymers by means of multi-stage emulsion polymerization is also familiar to those skilled in the art, further seen, for example, WO95 / 29963 and EP710680.

[0113] In this invention, the preparation of polymer B is a continuous free radical-initiated emulsion polymerization process in the presence of a free radical generating initiator and optionally a chain transfer agent. The continuous free radical-initiated emulsion polymerization process for preparing polymer B includes at least two polymerization stages. The emulsion polymerization for obtaining polymer B is a free radical-initiated emulsion polymerization carried out using appropriate heating and agitation (stirring). The free radical-initiated emulsion polymerization is typically carried out at atmospheric pressure and at temperatures ranging from 30°C to 100°C, preferably 50°C to 100°C, more preferably 60°C to 100°C, and even more preferably 60°C to 90°C. Suitable free radical generating initiators include persulfates (e.g., ammonium persulfate, potassium persulfate, and sodium persulfate), or redox initiator systems; combinations, such as tert-butyl hydroperoxide or hydroperoxide or cumene hydroperoxide with isoascorbic acid or sodium formaldehyde sulfoxylate and optionally FeEDTA, are useful. Based on the total monomer weight charged for the preparation of polymer B, the amount of initiator or initiator system is typically from 0.05% to 3% by weight.

[0114] Surfactants can be used to further (further because, advantageously, vinyl polymer A is self-dispersible in water in this invention) help disperse vinyl polymer A and / or vinyl polymer B in water. If a surfactant is used, it is preferably used in the free radical-initiated aqueous emulsion polymerization for the preparation of polymer B. Suitable surfactants include conventional anionic and / or nonionic surfactants and mixtures thereof, such as sodium, potassium, and ammonium dialkyl sulfosuccinates, sodium, potassium, and NH4 salts of sulfated oils, sodium, potassium, and NH4 salts of alkyl sulfonic acids, sodium, potassium, and NH4 salts of alkyl sulfates, alkali metal salts of sulfonic acids; fatty alcohols, ethoxylated fatty acids and / or fatty amides, and sodium, potassium, and NH4 salts of fatty acids, such as sodium stearate and sodium oleate. Other anionic surfactants include alkyl or (alkyl)aryl groups attached to sulfonic acid groups, sulfate half-ester groups (and subsequently to polyethylene glycol ether groups), phosphonic acid groups, phosphate analogs, and phosphate or carboxylic acid groups. Nonionic surfactants include polyethylene glycol ether compounds, and preferably polyethylene oxide compounds, as disclosed in "Non-Ionic Surfactants - Physical Chemistry" edited by M.J. Schick and M. Decker 1987. Preferred surfactants are anionic surfactants. If a surfactant is used, the amount of surfactant used is preferably from 0.03% to 3% by weight, based on the weight of vinyl polymer A and vinyl polymer B.

[0115] The weight ratio of polymer A to polymer B is 10:90 to 40:60, preferably 15:85 to 35:65, and most preferably 15:85 to 30:70.

[0116] According to the present invention, an aqueous coating formulation comprising the aqueous polymer dispersion as described above is further provided, wherein the polymer present in the aqueous polymer dispersion serves as a binder.

[0117] It has been surprisingly found that, using the waterborne coating formulations of the present invention, coatings with excellent chemical resistance, particularly water resistance, ethanol resistance, and coffee resistance, preferably also red wine resistance, mustard resistance, and onion resistance, combined with good mechanical properties, particularly anti-blocking properties, pencil hardness, and König hardness, can be obtained, while the amount of coalescing agent can be limited to less than 130 g coalescing agent / liter of waterborne coating formulation, and in colored and / or matte coating formulations, the aforementioned decrease in chemical resistance is minimal or at least acceptable. The coalescing agent is an organic solvent that acts as a film-forming aid. The coalescing agent is used to lower the minimum film-forming temperature of the polymer binder. Suitable examples include esters, such as methyl ethylene glycol acetate, ethyl ethylene glycol acetate, methoxypropyl acetate, and 2,2,4-trimethylpentane-1,3-diol monoisobutyrate (from Eastman). ), dipropylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate; ethers, such as butanediol, ethyl ethylene glycol ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol mono-n-butyl ether, diethylene glycol mono-n-hexyl ether, diethylene glycol diethyl ether, diethylene glycol dimethyl ether, diethylene glycol di-n-butyl ether, diethylene glycol di-n-hexyl ether, ethylene glycol di-2-ethylhexyl ether, ethylene glycol di-n-butyl ether, ... Dipropylene glycol dipropyl ether, dipropylene glycol dimethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monobutyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monotert-butyl ether, dipropylene glycol ditert-butyl ether, propylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monopropyl ether, propylene glycol monophenyl ether, propylene glycol monotert-butyl ether, propylene glycol diphenyl ether, propylene glycol monobutyl ether, tripropylene glycol monomethyl ether, and poly(allyl glycidyl ether). Mixtures of coalescing agents may also be used.

[0118] Preferably, the waterborne coating formulation contains less than 130 g VOC per liter of waterborne coating formulation. This VOC requirement is listed, for example, in IKEA Specification IOS-MAT-0066 version AA-163938-9,dd 17-01-2014.

[0119] The aqueous coating formulations of the present invention can be advantageously applied as single-component coating systems without the need for mixing reactive materials before application, as is required in two-component coating systems. Compared to two-component coating systems, single-component coating systems offer the advantage of being easier to store, handle, and apply. Using the aqueous polymer dispersions of the present invention, single-component coating systems can be obtained that exhibit low VOCs, good chemical resistance, particularly water resistance, ethanol resistance, and coffee resistance in transparent gloss, clear gloss, colored gloss, and colored gloss formulations, preferably also resistance to red wine, mustard, and onion, as well as good mechanical properties, particularly a favorable combination of anti-blocking properties, pencil hardness, and König hardness.

[0120] The aqueous coating formulations according to the invention comprise the aqueous polymer dispersion according to the invention, and may further comprise pigments, dyes, heat stabilizers, defoamers, fillers, matting agents, ultraviolet (UV) absorbers, and / or antioxidants. Non-limiting examples of coating formulations are varnishes; for example, overprint varnishes for paper or films; film coatings, such as printable substrates, barrier coatings, primers, and protective coatings; and inks, for example, for flexographic printing, gravure printing, and inkjet printing.

[0121] In the case of a transparent and glossy waterborne coating formulation, the weight percentage of polymer A, polymer B1, and polymer B2 together is preferably at least 90% by weight, more preferably at least 95% by weight, representing the solid content of the waterborne coating formulation.

[0122] In the case of a waterborne coating formulation containing a matting agent and a transparent surface, the weight percentage of polymer A, polymer B1, and polymer B2 together is preferably at least 75% by weight, more preferably at least 80% by weight, of the solid content of the waterborne coating formulation.

[0123] In the case of a water-based coating formulation containing pigments and a colored gloss, the weight percentage of polymer A, polymer B1, and polymer B2 together is preferably at least 45% by weight, more preferably at least 50% by weight, of the solid content of the water-based coating formulation.

[0124] In the case of a colored glossy waterborne coating formulation containing a matting agent and a pigment, the weight percentage of polymer A, polymer B1 and polymer B2 together is preferably at least 40% by weight, more preferably at least 45% by weight, of the solid content of the waterborne coating formulation.

[0125] The pigment can be any pigment known in the art, and is preferably an inorganic pigment. Examples of inorganic pigments include, but are not limited to, metal oxides such as titanium dioxide, zinc oxide, iron oxide, cobalt oxide, and chromium oxide; metal powder suspensions such as gold and aluminum; earth colors such as loess, ochre, and brown earth; and lead chromate. The most preferred inorganic pigment is titanium dioxide (rutile).

[0126] Organic pigments include mineral pigments, such as carbon black.

[0127] The pigment volume concentration (PVC) of the waterborne coating composition of the present invention, as defined below, is preferably in the range of 1% to 60%, advantageously 5% to 50%, particularly advantageously 10% to 40%, and most particularly 15% to 25%. The pigment volume concentration is defined as the volume of solid pigment / (volume of solid pigment + volume of solid polymer A + volume of solid polymer B).

[0128] Water-based coating formulations may contain matting agents. Suitable are organic and inorganic matting agents, such as those based on silica.

[0129] The present invention further provides a method for coating a substrate using an aqueous coating formulation as defined above. The present invention further provides a substrate having a coating, the coating being obtainable from or derived from an aqueous polymer composition as defined above. The present invention further provides a coated furniture, the coated furniture being obtained by (1) applying an aqueous coating formulation according to the present invention to the furniture to form a coating on the furniture, and (2) drying the coating.

[0130] The invention will now be further illustrated with reference to the following embodiments, but the invention is by no means limited to these embodiments. Unless otherwise specified, all parts, percentages, and ratios are on a weight basis. The prefix C before the example number indicates that the example number is comparative. Example:

[0131] Components and abbreviations used:

[0132] AA Acrylic Acid

[0133] S styrene

[0134] 2-Ethylhexyl acrylate (2-EHA)

[0135] HDDA 1,6-hexanediol diacrylate

[0136] LMCT lauryl thiol

[0137] Minimum film formation temperature (MFFT)

[0138] BG Butylene Glycol

[0139] DPnB dipropylene glycol n-butyl ether

[0140] DPM dipropylene glycol methyl ether

[0141] RH (Relative Humidity)

[0142] VOC (volatile organic compound) content

[0143] EtOH (ethanol)

[0144] BYK-011 is an antifoaming agent available from BYK.

[0145] Libratex AS-10 is an anionic surfactant available from Libra Specialty Chemicals, UK.

[0146] Tego Airex 902W is an antifoaming agent available from Evonik Industries.

[0147] Rheovis PU1190 is a low-shear associative thickener available from BASF.

[0148] Ceridust 9615 is a micronized blend of polyethylene and amide waxes available from Clariant.

[0149] Disperbyk 2015 Dispersant additives available from BYK

[0150] Tioxide TR92 is a multi-purpose grade of rutile titanium dioxide available from Huntsman.

[0151] Tego Foamex 810 is an antifoaming agent available from Evonik Industries.

[0152] SR10PG is a commercially available oligomer from Indulor AG with an acid value of 215-230 mg KOH / g solid, equivalent to 27.9-29.8% AA by weight.

[0153] Synthesis of Polymer A

[0154] In a high-pressure reactor, 623.3 g of methyl ethyl ketone was added. In a separate vessel, a mixture of styrene (1052.4 g), α-methylstyrene (167.8 g), and acrylic acid (305.0 g) in 135.5 g of methyl ethyl ketone was mixed with 15.3 g of tert-butyl peroxide. The reactor contents were heated to 128°C. The monomer feed was added to the reactor over 4 hours. After the monomer feed was complete, the vessel was rinsed with 30.0 g of methyl ethyl ketone. 30 minutes after the monomer feed was complete, 5.9 g of tert-butyl peroxide was added, followed by rinsing with 30.0 g of methyl ethyl ketone. This step was repeated after another 30 minutes. After stirring at 128°C for another 3 hours, the reactor was cooled, and when the temperature was below 70°C, 300.0 g of methyl ethyl ketone was added. The polymer solution had a solids content of 57.1% and a weight-average molecular weight of 27 kDa.

[0155] Preparation of dispersions of solution polymer A (DPA)

[0156] Polymer A (525.9 g) was placed in a reactor and heated to 40°C. A solution of ammonia (25%, 18 g) in demineralized water (72.0 g) was added over 3 minutes and mixed for 5 minutes. Next, demineralized water (681.0 g) was added over 7 minutes, and the reactor contents were mixed for 15 minutes. During this period, BYK-011 (0.10 g) was added. A vacuum was then applied (from 1 bar down to 65 mbar) to remove methyl ethyl ketone. The final solids content of DPA was 32.0%, pH 7.3, and particle size 47 nm.

[0157] Example 1

[0158] DPA (462.9 g), demineralized water (251.6 g), and Libratex AS-10 (10%, 22.6 g) were charged into the reactor. In a separate vessel, a solution of ammonium persulfate (0.6 g) in demineralized water (41.9 g) was prepared with Libratex AS-10 (5.6 g), and the pH was adjusted to >8 with ammonia (25%). In another vessel, a mixture of demineralized water (106.0 g), Libratex AS-10 (11.3 g), styrene (159.3 g), and 2-ethylhexyl acrylate (141.3 g) was prepared. The reactor contents were heated to 80°C. At 80°C, a solution of ammonium persulfate (1.2 g) in demineralized water (14.2 g, pH adjusted to >8 with ammonia) was added. After 5 minutes, the first monomer and initiator were fed over 60 minutes. The reactor was maintained at 80°C for 45 minutes. Concurrently, a second monomer feed was prepared, consisting of a mixture of demineralized water (106.0 g), Libratex AS-10 (3.8 g), and styrene (300.6 g), and a second initiator feed was prepared, consisting of a solution of ammonium persulfate (1.8 g) in demineralized water (97.8 g), Libratex AS-10 (1.9 g), and ammonia (25%), and the pH was adjusted to >8. Next, the second monomer feed and the second initiator feed were added over 60 minutes, and the feed container was rinsed with demineralized water (13 g total). The reaction mixture was maintained at 80°C for another 30 minutes, then cooled to room temperature. A BIT solution (10%, 9.0 g) was added to preserve the polymer dispersion, and the pH was adjusted to 7-8 with ammonia (25%).

[0159] Examples 2 to 7

[0160] Examples 2 through 7 were prepared according to similar formulations and processes applied to Example 1. The amount of polymer A, the type and amount of monomers used for polymers B1 and B2 are reported in Table 1.

[0161] Example 8

[0162] Example 1 was repeated, except that lauryl mercaptan was used to reduce the molecular weight of polymer B2. The second monomer feed was a mixture of demineralized water (106.0 g), Libratex AS-10 (3.8 g), styrene (291.59 g), and lauryl mercaptan (9.02 g). The weight-average molecular weight of polymer B2 was lower than that of polymer A.

[0163] Comparative Experiment C1

[0164] For comparative experiment C1, the following amounts were used in the reactor contents. SR10PG (150.5 g), demineralized water (524.5 g), Libratex AS-10 (10%, 22.6 g), and ammonia (39.6 g, 25%) were charged into the reactor. The reactor contents were heated to 80°C to dissolve the SR10PG. Once all the SR10PG had dissolved, the formulation and method described above for Example 1 were followed.

[0165] Comparative experiments C2 to C9

[0166] Comparative experiments C2 to C9 were prepared according to Example 1. The amount of polymer A and the type and amount of monomers used for polymers B1 and B2 are reported in Table 1.

[0167] For comparative experiment C2, the two monomer feeds from Example 1 were combined into a single monomer feed added within 120 minutes, and the two initiator feeds were combined into a single feed added within 120 minutes. For comparative experiments C5 and C6, a single monomer feed added within 120 minutes was used, and the two initiator feeds were combined into a single feed added within 120 minutes.

[0168] The specifications of the prepared polymers are given in Table 2.

[0169] Test methods

[0170] Particle size was measured using Malvern zetasizer nano S-90.

[0171] Solid content was measured at 105°C using a Mettler Toledo HB43-S Halogen.

[0172] MFFT was measured using a Sheen MFFT 90.

[0173] Viscosity was measured at 60 RPM at 20°C using a Brookfield Ametek DVE viscometer with a spindle S62.

[0174] VOC content was calculated as Where sg is the specific gravity of all raw materials present in the water-based coating formulation, the theoretically calculated specific gravity of the water-based coating formulation, and %VOC is the weight percentage of VOC relative to the water-based coating formulation. Volatile organic compounds are organic compounds with an initial boiling point of less than or equal to 250°C, measured at standard atmospheric pressure of 101.3 kPa.

[0175] Chemical resistance was assessed according to DIN 68861-1B and IKEA Specification number IOS-MAT-0066, version number AA-163938-9, dd 17-01-2014. A 21*14.9cm white melamine-finished MDF panel was used. Prior to testing, the panel was sanded (P280) and cleaned with a damp cloth, then dried with a clean, dry tea towel. A 150 g / m² chemical resistance coating was applied using a spray gun. 2 The panels were dried for 24 hours in a climate chamber at 22°C (+ / -2°C) and 50% + / -5% relative humidity, followed by aging at 50°C for 16 hours. When the panels cooled to room temperature, a staining assessment was initiated. The liquid was applied to the coating using soaked filter paper, and covered with a glass covered petri dish. The filter paper was obtained from MACHEREY-NAGEL, MN 440, with a diameter of 25 mm. After the surface effect had reached the specified duration, the paper was removed, the surface was patted dry, and after 24 hours, the surface was cleaned with paper soaked in a cleaning agent. Damage to the surface was then investigated. The cleaning agent had the following composition:

[0176] a) 12.5% ​​(m / m) of C 10 To C 14 Polymer alkylaryl sulfonate sodium,

[0177] b) 12.5% ​​(m / m) of C8 to C96 compounds with 5 to 15 ethoxylated groups 16 Polyethoxylated derivatives of primary or secondary alcohols, with a cloud point in 1% (m / m) aqueous solution ranging from 25°C to 75°C (the determination of cloud point is described in ISO 1065:1991).

[0178] c) 5.0% (m / m) ethanol,

[0179] d) 70% (m / m) distilled water.

[0180] Contamination assessments are conducted on a scale of 1 to 5, with 5 being the best and 1 being the worst. Contamination is scored according to the following levels:

[0181] 1 = Dramatic change:

[0182] Significant changes in surface structure, and / or

[0183] Discoloration or change in gloss and color, and / or

[0184] Surface material is removed, either entirely or partially, and / or

[0185] The filter paper still adheres to the surface.

[0186] 2 = Significant change:

[0187] The test area is clearly distinguishable from its surrounding adjacent areas and is visible from all viewing directions.

[0188] For example, discoloration, gloss and color change, and / or

[0189] The surface structure may vary slightly, such as swelling, fiber protrusion, cracking, or blistering.

[0190] 3 = Medium variation:

[0191] The test area is clearly distinguishable from the surrounding adjacent areas and is visible in multiple viewing directions, such as discoloration, gloss, and color changes;

[0192] The surface structure remains unchanged, for example, there is no expansion, fiber protrusion, cracking, or blistering.

[0193] 4 = minute changes:

[0194] The test area can only be distinguished from the surrounding areas, such as discoloration, gloss, and color change, when the light source is mirrored onto the test surface and reflected toward the observer's eye.

[0195] The surface structure remains unchanged, for example, there is no expansion, fiber protrusion, cracking, or blistering.

[0196] 5 = No change:

[0197] The test area cannot be distinguished from the surrounding adjacent areas.

[0198] When the panel cooled to room temperature, the gloss value and pencil hardness of the coating were also evaluated.

[0199] Gloss values ​​were measured at 20°, 60°, and 85° using a micro-Tri gloss meter.

[0200] Pencil hardness was measured using an Elcometer 501 pencil hardness tester. Pencils ranging in hardness from 6B (softest) to 6H (hardest) were pushed into the membrane, and the hardest pencil that did not penetrate the membrane was recorded.

[0201] Adhesion was measured by casting a 100 μm wet film onto a Leneta graph (Figure 8B). The film was dried at 22 °C (+ / - 2 °C) and 50% + / - 5% relative humidity for 10 minutes, followed by drying at 50 °C for 20 minutes. The coating was allowed to cool to room temperature. The film was then cut into fragments and tested using an adhesion tester from Koehler Instrument Company at room temperature over a period of 4 hours at 1 kg / cm². 2 Or 3kg / cm 2Under load, the coated sides were placed together. After the pressure was removed, the coated fragments were pulled apart. Anti-adhesion was rated on a scale of 0-5, where 5 is the best and 0 is the worst. Anti-adhesion was rated according to the following scale:

[0202] 0 = 75-100% sealed together, completely damaged.

[0203] 1 = 25-75% sealed together, severely damaged.

[0204] 2 = 0-25% sealed together, some damaged.

[0205] 3 = Medium viscosity, no damage.

[0206] 4 = Slightly sticky, no damage.

[0207] 5 = Non-sticky, no damage.

[0208] Koenig hardness was measured by casting a 150 μm wet film onto a glass plate. Prior to hardness measurement, the film was applied using a bird applicator and dried for 24 hours at 22°C (+ / -2°C) and 50% + / -5% relative humidity. Next, the panel was dried at 50°C for 16 hours. The panel was then allowed to cool to 22°C, and the Koenig hardness was measured again.

[0209]

[0210] Table 2. Specification

[0211]

[0212] A clear, glossy formulation was prepared using the ingredients and amounts (in grams) listed in Table 3. Test data for the clear, glossy formulation are presented in Tables 4 through 7.

[0213] Table 3. Transparent and glossy preparations

[0214]

[0215] Table 4. Test data on the mechanical properties of the transparent gloss coating.

[0216]

[0217] Table 5. Test data on the chemical resistance properties of the clear gloss coating according to DIN 68861-1B standard and IKEA R2 test.

[0218]

[0219] Table 6. Test data on the mechanical properties of the transparent gloss coating.

[0220]

[0221] Table 7. Test data on the chemical resistance properties of the clear gloss coating according to DIN 68861-1B standard and IKEA R2 test.

[0222]

[0223] Examples 1-Formulation 2 show that reducing VOC levels from 129 g / L to even 98 g / L still results in good performance.

[0224] Comparing experiments 3 and 4, the T of polymer B1 g The concentration was too high, and a defect-free film could not be formed, even when the VOC level was increased to well above 141 g / l. Therefore, gloss values, mechanical properties, and chemical resistance have not been evaluated. Similarly, for the transparent, colored glossy, and colored glossy formulations prepared with the binders of Comparative Experiments 3 and 4, even with such high amounts of coalescing agent (>>141 g / l), defect-free films could not be obtained, and therefore, the gloss values, mechanical properties, and chemical resistance of these formulations have not been evaluated.

[0225] Comparative experiments 2, 5, and 6, which used polymer systems with a single polymer phase, showed that for all three tested polymers, T... g Poor adhesion; 25℃, 35℃ and 49℃.

[0226] Comparative Experiment 7, in which polymer B1's T g Too low a value indicates poor stain resistance (IKEA R2: 1 hour for coffee; DIN 68861-1B: 16 hours for coffee / 6 hours for mustard) and low pencil / König hardness and poor anti-sticking properties.

[0227] Comparative Experiment 8, in which T of polymers B1 and B2 g Too low a value indicates poor stain resistance (IKEA R2: 1 hour for coffee; DIN 68861-1B: 16 hours for coffee / 6 hours for mustard) and low pencil / König hardness and poor anti-sticking properties.

[0228] Comparative Experiment 9, in which polymer B2's T g Too low a value indicates poor anti-adhesion properties.

[0229] The transparent glossy formulation was prepared using the ingredients and amounts (in grams) listed in Table 8. Test data for the transparent glossy formulation with a VOC of 98 g / L are presented in Tables 9 and 10.

[0230] Table 8. Transparent glossy formulation

[0231]

[0232] For C2, the amount of coalescing agent used (resulting in a VOC of 98 g / L) was too small to produce a defect-free coating, resulting in cracks within the coating. Even when the amount of coalescing agent was increased to a VOC level of 128 g / L (just below the VOC specification of 130 g / L listed in IKEA specification IOS-MAT-0066 version AA-163938-9,dd 17-01-2014 (see additional formulations in Table 8)), a crack-free coating could not be obtained. See also Figure 2 Therefore, gloss values, mechanical properties, and chemical resistance have not yet been evaluated.

[0233] Figure 1 and Figure 2

[0234] For Example 1—the adjuvant formulation with a VOC of 128 g / L ( Figure 1 ) and the comparative experiment showed that the adjuvant preparation with C2-VOC was 128 g / L ( Figure 2 Photographs of the coated Leneta charts have been taken. A transparent glossy formulation was cast as a 150 μm wet film onto the Leneta charts, and the Leneta charts were dried at 22 °C (+ / - 2 °C) and 50% + / - 5% relative humidity for 24 hours. Figure 1 The crack-free coating is shown. Figure 2 The coating with numerous cracks is shown.

[0235] Table 9. Test data on the mechanical properties of the transparent glossy coating.

[0236]

[0237] Table 10. Test data on the chemical resistance of the clear gloss coating according to DIN 68861-1B standard and IKEA R2 test.

[0238] IKEAR2 24-hour water resistance 5 5 5 1-hour resistance to EtOH (48%) 5 5 2 1 hour of coffee tolerance 5 5 5 total 15 15 12 DIN 68861-1B 1-hour resistance to EtOH (48%) 5 5 2 6-hour red wine resistance 5 5 5 16-hour coffee tolerance 5 5 5 16 hours of water resistance 5 5 5 6-hour mustard resistance 5 5 5 6-hour onion resistance 5 5 5 total 30 30 27

[0239] Comparative experiment 1, C1 shows that in transparent glossy coatings, adhesives prepared with oligomers with high acid values ​​have poor EtOH resistance.

[0240] Colored gloss formulations were prepared using the ingredients and amounts (in grams) listed in Table 11. Test data for the colored gloss formulations are presented in Tables 12 and 13.

[0241] Table 11. Coloring and glossing agents.

[0242]

[0243] For C2, a colored, glossy, defect-free coating with a VOC level of 121 g / L can be obtained. Although the VOC level of the clear gloss formulation is higher than that of the colored gloss formulation, the colored gloss formulation has a higher coalescing / binder weight ratio.

[0244] Table 12. Test data on the mechanical properties of the colored glossy coating.

[0245]

[0246] Table 13. Test data on the chemical resistance of colored gloss coatings according to DIN 68861-1B standard and IKEA R2 test.

[0247]

[0248] Examples 1-Formulation 4 demonstrate that reducing the VOC level from 121 g / L to even 84 g / L still results in good performance. The results indicate that in colored glossy coatings, adhesives with a single polymer phase having a Tg of 49 °C exhibit poor anti-blocking properties (Comparative Experiment C2), and adhesives prepared with oligomers having higher acid values ​​(Comparative Experiment C1) exhibit poor EtOH resistance.

[0249] Colored glossy formulations were prepared using the ingredients and amounts (in grams) listed in Table 14. Tables 15 through 18 provide test data for the colored glossy formulations.

[0250] Table 14. A glossy preparation that has been colored.

[0251]

[0252] For C2, a crack-free coating cannot be obtained. Therefore, gloss values, mechanical properties, and chemical resistance have not yet been evaluated.

[0253] All adhesives according to embodiments of the present invention were tested in colored glossy formulations, which are the most challenging formulations.

[0254] Table 15.Test data on the mechanical properties of the colored glossy coating.

[0255]

[0256] Table 16. Test data on the chemical resistance of tinted glossy coatings according to DIN 68861-1B and IKEA R2 testing standards.

[0257]

[0258] Table 17. Test data on the mechanical properties of the colored glossy coating.

[0259]

[0260] Table 18. Test data on the chemical resistance of tinted glossy coatings according to DIN 68861-1B and IKEA R2 testing standards.

[0261]

[0262] Examples 1-Formulation 6 show that reducing VOC levels from 120 g / L to even 84 g / L still results in good performance.

[0263] Comparative experiment 1, C1 shows that in colored glossy coatings, adhesives prepared with oligomers with high acid values ​​have poor EtOH resistance.

[0264] Comparative experiment C7, in which polymer B1's T g Too low, indicating poor stain resistance (DIN 68861-1B: coffee 16 hours) and low pencil / König hardness.

[0265] Comparative experiment C8, in which polymers B1 and B2 have T g Too low, indicating poor stain resistance (DIN 68861-1B coffee 16 hours) and low pencil / König hardness.

[0266] Comparative experiment C9, in which polymer B2's T g Too low, indicating low pencil hardness.

Claims

1. A method for preparing an aqueous polymer dispersion, wherein the method comprises: Free radical-initiated emulsion polymerization is carried out in an aqueous medium in the presence of at least one vinyl polymer A to obtain polymer B, said polymer B comprising a vinyl polymer phase B1 with a glass transition temperature of -20°C to +15°C calculated by the Fox equation and a vinyl polymer phase B2 with a glass transition temperature of +50°C to +110°C calculated by the Fox equation, provided that the glass transition temperature difference between polymer B1 and polymer B2 is at least 40°C. in The weight ratio of polymer B1 to polymer B2 is 80:10 to 10:

20. At least one polymer A is obtained by a method comprising the following steps: The following substances undergo free radical-initiated bulk or solution polymerization: From 5% to 25% by weight of at least one carboxylic acid-functionalized olefinic unsaturated monomer A1. wherein the monomer A1 is selected from acrylic acid, methacrylic acid, acrylic acid carboxyethyl ester, citraconic acid, crotonic acid, fumaric acid, itaconic acid, monoalkyl esters of itaconic acid and potentially carboxylic acid functional ethylenically unsaturated monomers and combinations thereof, and 75% to 95% by weight of at least one olefinic unsaturated monomer A2, different from said monomer A1. wherein the monomer A2 is selected from the group consisting of acrylic esters, methacrylic esters, optionally C 1-10 hydrocarbyl substituted styrenes, dienes, vinyl esters, acrylonitrile, methacrylonitrile, ethylenically unsaturated halides, and any mixture thereof, The amount mentioned therein is given relative to the total weight of monomers charged in the polymerization process for preparing the vinyl polymer A. The glass transition temperature of the at least one vinyl polymer A, calculated using the Fox equation, is between 40°C and 150°C. The weight-average molecular weight of the at least one polymer A, as determined by SEC, is between 1000 g / mol and 70000 g / mol. The weight-average molecular weight of polymer A is lower than that of polymer B, and the weight-average molecular weight is determined by SEC. The weight ratio of polymer A to polymer B is from 10:90 to 40:

60. And among them Polymer phase B1 was prepared by aqueous emulsion polymerization initiated by the free radicals of the following substances in the presence of polymer A: 0% to 5% by weight of at least one carboxylic acid-functionalized olefinic unsaturated monomer B1.1, and From 95% to 100% by weight, at least one olefinically unsaturated monomer B1.2 different from monomer B1.1, wherein the amount is given relative to the total weight of monomers charged in the polymerization for preparing vinyl polymer B1. And among them, Polymer phase B2 was prepared by aqueous emulsion polymerization initiated by the free radicals of the following substances in the presence of polymer A: 0% to 5% by weight of at least one carboxylic acid functionalized olefinic unsaturated monomer B2.1, and From 95% to 100% by weight, at least one olefinically unsaturated monomer B2.2 different from monomer B2.1, wherein the amount is given relative to the total weight of monomers charged in the polymerization for preparing vinyl polymer B2. And among them, Monomers B1.2 and B2.2 are independently selected from the group consisting of: acrylates, methacrylates, styrene optionally substituted with C1-10 hydrocarbon groups, dienes, vinyl esters, acrylonitriles, methacrylonitriles, olefinic unsaturated halides, and any mixtures thereof. And among them, Monomers B1.2 and B2.2 may optionally have functional groups selected from the following: silane, epoxy, hydroxyl, ketone, aldehyde and at least two non-conjugated olefinic unsaturated double bonds.

2. The method of claim 1, wherein, Monomers B1.2 and B2.2 are independently selected from the group consisting of acrylates, methacrylates, styrene optionally substituted with C1-10 hydrocarbon groups, and any mixture thereof.

3. The method of claim 1, wherein the method for preparing the at least one polymer A further comprises at least partially deprotonating the carboxylic acid group to obtain polymer A.

4. The method of claim 1, wherein the method further comprises dispersing the at least one polymer A in water prior to performing the radical-initiated emulsion polymerization to obtain the polymer B.

5. The method of claim 1, wherein 10% to 22.5% by weight of monomer A1 and 77.5% to 90% by weight of monomer A2 are used, wherein the amounts are given relative to the total weight of monomers charged in the polymerization for preparing the vinyl polymer A.

6. The method of claim 1, wherein the total amount of monomers A1 and A2 is 100 by weight.

7. The method according to claim 1, wherein the monomer A1 is selected from acrylic acid, methacrylic acid, itaconic acid, fumaric acid and mixtures thereof.

8. The method according to claim 1, wherein the monomer A1 is methacrylic acid and / or acrylic acid.

9. The method of claim 1, wherein the monomer A2 is selected from acrylates, methacrylates, styrene optionally substituted with C1-10 hydrocarbon groups, and any mixture thereof.

10. The method according to claim 1, wherein the monomer A2 is selected from methyl methacrylate, ethyl methacrylate, 4-methyl-2-pentyl methacrylate, 2-methylbutyl methacrylate, isoamyl methacrylate, sec-butyl methacrylate, n-butyl methacrylate, 2-ethylhexyl methacrylate, 2-octyl methacrylate, lauryl methacrylate, isodecanyl methacrylate, cyclohexyl methacrylate, isobornyl methacrylate, and / or mixtures thereof.

11. The method according to claim 1, wherein the monomer A2 is selected from methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-butyl methacrylate, n-butyl acrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, styrene, α-methylstyrene, and any mixture thereof.

12. The method according to claim 1, wherein the monomer A2 is selected from styrene, α-methylstyrene, methyl methacrylate, n-butyl acrylate and / or 2-ethylhexyl acrylate and any mixture thereof.

13. The method according to claim 1, wherein the monomer A2 is styrene and / or α-methylstyrene.

14. The method according to claim 1, wherein the weight-average molecular weight of the at least one polymer A is from 5000 g / mol to 60000 g / mol.

15. The method according to claim 1, wherein the glass transition temperature of the at least one vinyl polymer A is from 60°C to 140°C.

16. The method of claim 1, wherein the monomers A1 and A2 are selected such that the Hansch parameter of the at least one polymer A is greater than 1.35 and at most 2.20, wherein the Hansch parameter is calculated using the group contribution method.

17. The method of claim 1, wherein the glass transition temperature difference between polymer B1 and polymer B2 is at least 50°C.

18. The method of claim 1, wherein the glass transition temperature difference between polymer B1 and polymer B2 is at least 60°C.

19. The method of claim 1, wherein the glass transition temperature difference between polymer B1 and polymer B2 is at least 70°C.

20. The method according to any one of claims 1-19, wherein the glass transition temperature difference between polymer B1 and polymer B2 is at least 50°C.

21. The method according to any one of claims 1-19, wherein the glass transition temperature difference between polymer B1 and polymer B2 is at least 60°C.

22. The method according to any one of claims 1-19, wherein the glass transition temperature difference between polymer B1 and polymer B2 is at least 70°C.

23. The method according to any one of claims 1-19, wherein said monomers B1.2 and B2.2 are independently selected from the group consisting of acrylates, methacrylates, styrene optionally substituted with C1-10 hydrocarbon groups, and any mixture thereof.

24. The method according to any one of claims 1-19, wherein said monomers B1.2 and B2.2 are independently selected from the group consisting of: methyl methacrylate, ethyl methacrylate, 4-methyl-2-pentyl methacrylate, 2-methylbutyl methacrylate, isoamyl methacrylate, sec-butyl methacrylate, n-butyl methacrylate, tert-butyl methacrylate, 2-ethylhexyl methacrylate, 2-octyl methacrylate, lauryl methacrylate, isodecanyl methacrylate, cyclohexyl methacrylate and / or mixtures thereof.

25. The method according to any one of claims 1-19, wherein said monomers B1.2 and B2.2 are independently selected from the group consisting of: methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-butyl methacrylate, n-butyl acrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, styrene, α-methylstyrene, and any mixture thereof.

26. The method according to any one of claims 1-19, wherein said monomers B1.2 and B2.2 are independently styrene, α-methylstyrene, methyl methacrylate, n-butyl acrylate, 2-ethylhexyl acrylate, or any mixture thereof.

27. The method according to any one of claims 1-19, wherein said monomer B1.2 and monomer B2.2 are independently styrene and / or α-methylstyrene.

28. The method according to any one of claims 1-19, wherein the weight ratio of polymer B1 to polymer B2 is 80:10 to 10:

20.

29. The method according to any one of claims 1-19, wherein the Hansch parameters of polymer B1 and polymer B2 are independently greater than 1.20 and at most 4.00, wherein the Hansch parameters are calculated using the group contribution method.

30. The method according to any one of claims 1-19, wherein the preparation of polymer phase B1 is carried out before the preparation of polymer phase B2, or vice versa.

31. The method according to any one of claims 1-19, wherein the polymer B1 has a weight-average molecular weight of at least 100,000 g / mol as determined by SEC, and the polymer B2 has a weight-average molecular weight of less than 100,000 g / mol as determined by SEC.

32. The method according to any one of claims 1-19, wherein the weight-average molecular weight of each of said polymer B1 and said polymer B2, as determined by SEC, is at least 100,000 g / mol.

33. The method of any one of claims 1-19, wherein polymer B comprises two polymer phases B1 and B2.

34. The method according to any one of claims 1-19, wherein the weight ratio of polymer A to polymer B is from 15:85 to 35:

65.

35. An aqueous polymer dispersion obtained by the method according to any one of claims 1-34.

36. The aqueous polymer dispersion of claim 35, wherein, based on the solid content of the aqueous polymer dispersion, the amount of polymer A, polymer B1 and polymer B2 together in the aqueous polymer dispersion is greater than 60 by weight.

37. The aqueous polymer dispersion of claim 35, wherein, based on the solid content of the aqueous polymer dispersion, the amount of polymer A, polymer B1 and polymer B2 together in the aqueous polymer dispersion is greater than 70% by weight.

38. The aqueous polymer dispersion of claim 35, wherein, based on the solid content of the aqueous polymer dispersion, the amount of polymer A, polymer B1 and polymer B2 together in the aqueous polymer dispersion is greater than 80 by weight.

39. The aqueous polymer dispersion of claim 35, wherein, based on the solid content of the aqueous polymer dispersion, the amount of polymer A, polymer B1 and polymer B2 together in the aqueous polymer dispersion is greater than 90% by weight.

40. The aqueous polymer dispersion of claim 35, wherein, based on the solid content of the aqueous polymer dispersion, the amount of polymer A, polymer B1 and polymer B2 together in the aqueous polymer dispersion is greater than 95% by weight.

41. An aqueous coating formulation comprising an aqueous polymer dispersion according to any one of claims 35-40.

42. The waterborne coating formulation according to claim 41, wherein the amount of agglomerator present in the waterborne coating formulation is less than 130 g / L.

43. The waterborne coating formulation according to claim 41, wherein the waterborne coating formulation comprises at least one pigment and / or at least one matting agent.

44. The waterborne coating formulation according to claim 41, wherein the waterborne coating formulation is a single-component coating system.

45. The waterborne coating formulation according to claim 42, wherein the waterborne coating formulation comprises at least one pigment and / or at least one matting agent.

46. ​​The waterborne coating formulation according to claim 42, wherein the waterborne coating formulation is a single-component coating system.

47. A coated furniture, said coated furniture being obtained by (1) applying an aqueous coating formulation according to any one of claims 41 to 46 onto the furniture to form a coating on the furniture, and (2) drying said coating.

48. A method of coating a substrate, providing an aqueous coating formulation according to any one of claims 41 to 46.

49. A substrate having a coating obtainable from an aqueous coating formulation according to any one of claims 41 to 46.

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