CN111349190B

CN111349190B - Aqueous polymer emulsion, method for the production thereof and use thereof

Info

Publication number: CN111349190B
Application number: CN201911325514.3A
Authority: CN
Inventors: 孙丽超; 曾重; 李真真; 周娟; 徐双双
Original assignee: BASF SE
Current assignee: BASF SE
Priority date: 2018-12-21
Filing date: 2019-12-20
Publication date: 2023-05-26
Anticipated expiration: 2039-12-20
Also published as: CN111349190A

Abstract

The invention relates to an aqueous polymer emulsion, a method for the production thereof and the use thereof. The aqueous multistage polymer emulsion comprises a multistage polymer having a total calculated Fox Tg (Tg 0) in the range of-15 to +5 ℃, a calculated difference (Δtg) between the Fox Tg (Tg 2) of the second stage polymer and the Fox Tg (Tg 1) of the first stage polymer of more than 10 ℃, and a weight ratio of the first stage polymer to the second stage polymer in the range of 95:5 to 30:70 based on the total amount of monomers used for polymerization per stage. The emulsion has balanced Low Temperature Film Flexibility (LTFF), DPUR and acid resistance properties.

Description

Aqueous polymer emulsion, method for the production thereof and use thereof

Technical Field

The present invention relates to aqueous multistage polymer emulsions, to a process for their preparation and to their use. In particular, the present invention relates to multistage polymer emulsions suitable for coating applications. The invention also discloses a preparation method and application thereof.

Background

Aqueous polymer emulsions are used in many applications, such as coatings, adhesives, and the like. When applied to coatings, particularly exterior wall coatings, polymeric materials are exposed to the atmosphere and subjected to weathering processes wherein the materials dissolve, wear or break into smaller and smaller pieces when contacted with acids, bases, dust, and the like. It is therefore desirable that aqueous polymer emulsions can have excellent resistance to weathering processes. In addition, film flexibility, particularly Low Temperature Film Flexibility (LTFF), is also an important property of coatings, which is typically created by emulsions used in coatings.

Many solutions have been proposed to impart LTFF, acid resistance and stain resistance (DPUR) to coatings. And, emphasis has been placed on aqueous emulsions as the major component in coating formulations. In general, stain resistance requires a hard emulsion polymer, while film flexibility requires a soft emulsion polymer.

CN1256295a discloses a method of balancing DPUR and flexibility by using a multi-stage polymer emulsion. The multistage polymer contains both hard and soft segments in the final polymer. However, to address DUPR performance, the flexibility of the film is sacrificed to some extent.

JP2003147150a discloses an aqueous polymer dispersion capable of forming a coating film having low-temperature flexibility and a method for producing the same. It constructs a two layer film in which layer a comprises a polymer having carboxyl groups with a measured Tg of-15 ℃ and layer B comprises a polymer with a measured Tg of 30-150 ℃. After the formation of the layer a, a layer B is formed by polymerization. This method requires two steps to form a film and requires the use of two different polymers, and is therefore not ideal for exterior wall coatings.

CN106118175a discloses an acid and corrosion resistant coating. The coating comprises a fluorinated acrylate emulsion and polydimethyldiallylammonium chloride (polydadmac). In this application, no antacid data is provided. Also, the use of fluorinated acrylate emulsions will increase the overall cost of the coating.

Thus, there remains a need to develop an emulsion system that is more suitable for use in coatings, especially exterior wall coatings, that requires a balance of Low Temperature Film Flexibility (LTFF), DPUR and acid resistance properties.

Disclosure of Invention

It is an object of the present invention to provide aqueous multistage polymer emulsions having balanced Low Temperature Film Flexibility (LTFF), DPUR and acid resistance properties. The aqueous multistage polymer emulsion comprises a polymer having a total calculated Fox Tg (Tg 0) in the range of-15 ℃ to +5 ℃, a calculated difference (Δtg) between the Fox Tg (Tg 2) of the second stage polymer and the Fox Tg (Tg 1) of the first stage polymer of more than 10 ℃, and a weight ratio of the first stage polymer to the second stage polymer in the range of 95:5 to 30:70 based on the total amount of monomers used for polymerization of each stage.

It is another object of the present invention to provide a method for preparing the same. The aqueous multistage polymer emulsion is synthesized by multistage emulsion polymerization.

It is a third object of the present invention to provide the use of aqueous multistage polymer emulsions, i.e. coatings, especially architectural coatings.

Detailed Description

Unless otherwise defined, all terms/idioms/naming principles used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention pertains.

The words "a," "an," and "the" when used to define a term include both the plural and singular forms of that term.

The term "polymer" as used herein includes both homopolymers, i.e. polymers prepared from a single reactive compound, and copolymers, i.e. polymers prepared by the reaction of at least two monomer compounds having polymer forming reactivity.

The term "multistage emulsion polymer" means a polymer that includes at least a first stage polymer formed during a first emulsion polymerization process and includes at least a second stage polymer that is subsequently polymerized during a second emulsion polymerization process.

The names (meth) acrylate and similar names are used herein as abbreviations for "acrylate and/or methacrylate".

All percentages and ratios are by weight unless otherwise indicated.

The present invention relates to aqueous multistage polymer emulsions having balanced Low Temperature Film Flexibility (LTFF), DPUR and acid resistance properties. The aqueous multistage polymer emulsion comprises a multistage polymer having a total calculated Fox Tg (Tg 0) in the range of-15 ℃ to +5 ℃, a calculated difference (Δtg) between the Fox Tg (Tg 2) of the second stage polymer and the Fox Tg (Tg 1) of the first stage polymer of more than 10 ℃, and a weight ratio of the first stage polymer to the second stage polymer in the range of 95:5 to 30:70 based on the total amount of monomers used for polymerization per stage.

In a preferred embodiment, the total calculated Fox Tg (Tg 0) of the aqueous multistage polymer emulsion is in the range of-10 ℃ to +5 ℃, the calculated difference (Δtg) between Fox Tg (Tg 2) of the second stage polymer and Fox Tg (Tg 1) of the first stage polymer exceeds 10 ℃, and the weight ratio of the first stage polymer to the second stage polymer is in the range of 90:10 to 40:60 based on the total amount of monomers used for polymerization of each stage.

In a more preferred embodiment, the total calculated Fox Tg (Tg 0) of the aqueous multistage polymer emulsion is in the range of-10 ℃ to 0 ℃, the calculated difference (Δtg) between Fox Tg (Tg 2) of the second stage polymer and Fox Tg (Tg 1) of the first stage polymer is in excess of 15 ℃, and the weight ratio of the first stage polymer to the second stage polymer is in the range of 90:10 to 50:50 based on the total amount of monomers used for polymerization of each stage.

In the context of the present application, the term Fox Tg refers to the glass transition temperature (Tg) calculated according to the following Fox equation disclosed in t.g. Fox, bulletin of the American Physical Society, volume 1, phase 3, page 123 (1956):

1/Tg＝W ₁ /Tg ₁ +W ₂ /Tg ₂ +...+W _n /Tg _n

wherein, the liquid crystal display device comprises a liquid crystal display device,

W ₁ 、W ₂ 、…W _n mass fractions of monomers 1, 2,..n, respectively, and

Tg ₁ 、Tg ₂ 、…Tg _n glass transition temperatures in kelvin for homopolymers of monomers 1, 2,..n, respectively.

The homopolymer Tg values of most monomers are known and are listed, for example, in Ullmann's Ecyclopedia ofIndustrial Chemistry, vol.5, column A21, page 169, VCH Weinheim, 1992. Other sources of glass transition temperatures for homopolymers include, for example, J.Brandrup, E.H.Immergut, polymer Handbook, first edition, J.Wiley, new York 1966, second edition, J.Wiley, new York 1975, and third edition, J.Wiley, new York 1989.

The aqueous multistage polymer emulsion comprises one or more multistage polymers in an aqueous medium. There is no particular limitation on the monomers used to prepare the polymer. However, the resulting polymer should have a total Fox Tg in the range of-15 ℃ to 5 ℃, preferably-10 ℃ to 5 ℃ and most preferably-10 ℃ to 0 ℃. It is also necessary that the weight ratio of the first stage polymer to the second stage polymer is in the range of 95:5 to 30:70, preferably 90:10 to 40:60 and most preferably 90:10 to 50:50 based on the total amount of monomer used for polymerization in each stage. In addition, the calculated difference (ΔTg) between the Fox Tg (Tg 2) of the second stage polymer and the Fox Tg (Tg 1) of the first stage polymer must be maintained at 10℃or higher, and preferably 15℃or higher.

The monomers used for the first stage polymer and the second stage polymer may each be independently selected from monomers known in the coating art to be useful in preparing aqueous polymer dispersions. The types of monomers used for the first stage polymer and the second stage polymer may be the same or different, so long as the resulting polymer may have a specific Tg as discussed above.

The monomers for the first stage polymer and the second stage polymer may each independently comprise:

(A) The total amount of the at least one hydrophobic monoethylenically unsaturated monomer (a) may be at least 80 wt%, preferably at least 85 wt%, more preferably at least 90 wt%, most preferably at least 95 wt%; and

(B) The total amount of the at least one hydrophilic monoethylenically unsaturated monomer (b) may be at least 0.1% by weight and not more than 20% by weight, preferably not more than 15% by weight, more preferably not more than 10% by weight, most preferably not more than 5% by weight;

each based on the total weight of monomers used to prepare the respective first stage and second stage polymers.

The at least one hydrophobic monoethylenically unsaturated monomer (a) may be selected from the group consisting of (meth) acrylate monomers, (meth) acrylonitrile monomers, styrene monomers, vinyl alkanoate monomers, and monoethylenically unsaturated dicarboxylic acid ester monomers and monoethylenically unsaturated tricarboxylic acid ester monomers.

In particular, the (meth) acrylate monomer may be (meth) acrylic acid C ₁ -C ₁₉ Alkyl esters such as, but not limited to: methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate, n-octyl (meth) acrylate, n-decyl (meth) acrylate, n-dodecyl (i.e., lauryl (meth) acrylate), tetradecyl (meth) acrylate, oleyl (meth) acrylate, palmityl (meth) acrylate, stearyl (meth) acrylate, isobornyl (meth) acrylate, benzyl (meth) acrylate, phenyl (meth) acrylate, and mixtures thereof.

In particular, the styrene monomer may be unsubstituted styrene or C1-C6-alkyl substituted styrene, such as, but not limited to: styrene, alpha-methylstyrene, o-methylstyrene, m-methylstyrene and p-methylstyrene, o-ethylstyrene, m-ethylstyrene and p-ethylstyrene, o-dimethylstyrene, p-dimethylstyrene, o-diethylstyrene, p-diethylstyrene, isopropylstyrene, o-methyl-p-isopropylstyrene, or any mixture thereof.

In particular, the vinyl alkanoate monomer may be C ₂ -C ₁₁ Vinyl esters of alkanoic acids such as, but not limited to: vinyl acetate, vinyl propionate, and ethyl butyrateVinyl esters, vinyl valerate, vinyl caproate, vinyl versatate, or mixtures thereof.

In addition, monoethylenically unsaturated dicarboxylic acid ester monomers and monoethylenically unsaturated tricarboxylic acid ester monomers may be full esters of monoethylenically unsaturated dicarboxylic acids and monoethylenically unsaturated tricarboxylic acids, such as, but not limited to: diethyl maleate, dimethyl fumarate, ethyl methyl itaconate, or any mixture thereof.

In a preferred embodiment of the invention, one or more (meth) acrylic acids C ₁ -C ₁₂ Alkyl esters, such as methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate and 2-ethylhexyl (meth) acrylate, styrene, or mixtures thereof, are selected as the at least one hydrophobic monoethylenically unsaturated monomer (a).

The at least one hydrophilic monoethylenically unsaturated monomer (b) may be a monoethylenically unsaturated monomer containing at least one functional group selected from the group consisting of carboxyl, carboxylic anhydride, sulfonic acid, phosphoric acid, hydroxyl and amide.

In particular, hydrophilic monoethylenically unsaturated monomers (b) include, but are not limited to: monoethylenically unsaturated carboxylic acids, such as (meth) acrylic acid, itaconic acid, fumaric acid, citraconic acid, sorbic acid, cinnamic acid, glutaconic acid and maleic acid; monoethylenically unsaturated carboxylic anhydrides, such as itaconic anhydride, fumaric anhydride, citraconic anhydride, sorbic anhydride, cinnamic anhydride, glutaric anhydride and maleic anhydride; monoethylenically unsaturated amides, in particular N-alkyl-alkanolamides, such as (meth) acrylamide, N-methylol (meth) acrylamide, 2-hydroxyethyl (meth) acrylamide; and hydroxyalkyl esters of monoethylenically unsaturated carboxylic acids, such as hydroxyethyl (meth) acrylate and hydroxypropyl (meth) acrylate.

In a preferred embodiment of the present invention, acrylic acid, methacrylic acid, itaconic acid, acrylamide, methacrylamide, or mixtures thereof are preferred as the at least one hydrophilic monoethylenically unsaturated monomer (b).

The monomers of the invention may further comprise one or more crosslinking monomers (c). The crosslinking monomer may be selected from di-or poly-isocyanatesIsocyanate, polyethylenimine, polycarbodiimide and poly (I)

Oxazolines, glyoxals, triols, epoxy molecules, organosilanes, carbamates, diamines and triamines, hydrazides, carbodiimides and polyethylenically unsaturated monomers. In the present invention, suitable crosslinking monomers include, but are not limited to: glycidyl (meth) acrylate, N-methylol (meth) acrylamide, (isobutoxymethyl) acrylamide, vinyltrialkoxysilane (e.g., vinyltrimethoxysilane); alkyl vinyl dialkoxysilanes (e.g., dimethoxymethyl vinyl silane), (meth) acryloxyalkyl trialkoxysilanes (e.g., (meth) acryloxyethyl trimethoxysilane, (3-acryloxypropyl) trimethoxysilane and (3-methacryloxypropyl) trimethoxysilane), allyl methacrylate, diallyl phthalate, 1, 4-butanediol dimethacrylate, 1, 2-ethylene glycol dimethacrylate, 1, 6-hexanediol diacrylate, divinylbenzene, or any mixtures thereof.

The amount of crosslinking agent that can be added is not more than 10 wt.%, preferably not more than 8 wt.%, more preferably not more than 5 wt.%, based on the total weight of all monomers used in the polymer synthesis.

The calculated Fox Tg of the polymer can be controlled by varying the weight ratio of hard and soft monomers applied to the polymer synthesis. In the present invention, a monomer is considered a hard monomer if it can produce a homopolymer with a calculated Fox Tg of more than 10 ℃, otherwise it is considered a soft monomer.

Soft monomers may include, but are not limited to: methyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, isooctyl acrylate, nonyl acrylate, ethyl acrylate, decyl methacrylate, isodecyl methacrylate, hexyl (meth) acrylate, cyclohexyl acrylate, dodecyl (meth) acrylate, octyl methacrylate, propyl acrylate, ethylene adipate, diethyl fumarate, 1, 4-butadiene, 1-pentene, di-2-ethylhexyl maleate, di-2-ethylhexyl fumarate, and mixtures thereof. In a preferred embodiment, alkyl acrylates having 4 to 12 carbon atoms in the alkyl radical, such as n-butyl acrylate and 2-ethylhexyl acrylate, are used as soft monomers.

Hard monomers may include, but are not limited to: methyl methacrylate, t-butyl acrylate, benzyl methacrylate, ethyl methacrylate, acrylamide, acrylic acid, methacrylic acid, itaconic acid, fumaric acid, citraconic acid, sorbic acid, cinnamic acid, glutaric acid, and maleic acid vinyl alcohol, vinyl acetate, vinyl butyrate, vinyl formate, vinyl valerate, vinyl versatate, styrene, C1-C6-alkyl substituted styrenes. In a preferred embodiment, acrylic acid, methacrylic acid, methyl (meth) acrylate, styrene, acrylamide, methacrylamide, or mixtures thereof are used as the hard monomer.

It is essential that the total calculated Fox Tg (Tg 0) of the emulsion polymer is in the range of-15 ℃ to +5 ℃, preferably-10 ℃ to +5 ℃ and most preferably-10 ℃ to 0 ℃. A high total Fox Tg of the polymer would decrease film flexibility at low temperatures, while a too low total Fox Tg would decrease DPUR. Acid resistance is also affected by Fox Tg.

It is also necessary to control the weight ratio of the first stage polymer to the second stage polymer and the calculated difference (ΔTg) between the Fox Tg (Tg 2) of the second stage polymer and the Fox Tg (Tg 1) of the first stage polymer. In the present invention, the weight ratio of the first stage polymer to the second stage polymer is in the range of 95:5 to 30:70, preferably in the range of 90:10 to 40:60 and most preferably in the range of 90:10 to 50:50, based on the total amount of monomers used for polymerization in each stage. In the present invention, ΔTg is preferably 10℃or higher, more preferably 15℃or higher.

The aqueous multistage polymer emulsion of the present invention can be prepared by a multistage polymerization process comprising polymerization of a first stage monomer to produce a first stage polymer, and subsequent polymerization of a second stage monomer to produce a second stage polymer. Multistage polymerization techniques well known in the art may be used to prepare the aqueous multistage copolymer dispersions of the present invention, such as the methods disclosed in US2728804A, US20170096575A1, US20170355802A1, and the like.

Emulsion polymerization can be carried out in batch operation or in the form of a feed process (i.e., the reaction mixture is fed to the reactor in a staged or gradient procedure). The feed method is the preferred method. In this process, a small portion of the reaction mixture of the first stage monomers may be introduced as an initial charge and heated to a polymerization temperature that will typically produce polymer seeds. The remainder of the polymerization mixture of the first stage polymer is then fed to the reactor, typically by means of two or more spatially separated feed streams. After completion of the feed, the reaction is further allowed to proceed for a further 10 to 30 minutes and, optionally, the mixture is then completely or partially neutralized. After the completion of the first stage polymerization, the polymerization mixture of the second stage monomers is supplied to the reactor in the same manner as described above. After the feed was completed, the polymerization was maintained for another 30 to 90 minutes. Thereafter, the reaction mixture may be treated with an oxidizing agent, a neutralizing agent, or the like.

In the multistage polymerization process, most surfactants known to those skilled in the art can be used. The surfactant used according to the present invention may be a non-reactive surfactant, a reactive surfactant, or a combination thereof. The surfactant may be formulated with the monomer and fed to the reactor of the reaction. Alternatively, the surfactant may be added to the reaction medium first, followed by the monomer feed. The surfactant may be used in an appropriate amount known to those skilled in the art (e.g., in a total amount of 0.1 to 6 wt%, based on the total weight of the monomers).

The surfactant may be a non-reactive anionic and/or nonionic surfactant. Suitable non-reactive anionic surfactants include, for example, but are not limited to: alkyl, aryl or alkylaryl sulfates, sulfonates or phosphates; alkyl sulfonic acid; sulfosuccinate; fatty alcohol ether sulfates and fatty acids. Suitable non-reactive nonionic surfactants include, for example, ethoxylates of alcohols or phenols, such as polyoxyethylene alkylphenyl ethers.

The surfactant may also be a polymerizable surfactant, also known as a reactive surfactant, containing at least An ethylenically unsaturated functional group. Suitable polymerizable surfactants include, for example, but are not limited to: allyl polyoxyalkylene ether sulfate such as allyl polyoxyalkylene alkyl ether sodium sulfate; allyl alkyl succinate sulfonate; allyl ether hydroxy propane sulfonates, such as sodium salt; polyoxyethylenestyrenated phenyl ether sulfates, e.g. ammonium salts, e.g. DKS

AR 1025 and DKS->

AR 2020; polyoxyethylene alkylphenyl ether ammonium sulfate; polyoxyethylene allyloxy nonylphenoxypropyl ether, and compounds such as +.>

Acrylic acid phosphate esters such as PAM 100 and the like

Acrylic acid phosphate esters such as PAM 200.

Emulsion polymerization may be carried out in the presence of a variety of common initiating systems including, but not limited to, thermal initiators or redox initiators. The initiator is generally used in an amount of not more than 10% by weight, preferably from 0.02 to 5% by weight, more preferably from 0.1 to 1.5% by weight, based on the total weight of the two-stage monomers.

Thermal initiators such as peroxides, persulfates and azo compounds are generally used. Peroxides that may be used include, but are not limited to: inorganic peroxides such as hydrogen peroxide or peroxodisulfates; or organic peroxides, for example tert-butyl hydroperoxide, p-menthyl hydroperoxide or cumyl hydroperoxide, tert-butyl perpivalate and dialkyl or diaryl peroxides, such as di-tert-butyl or dicumyl peroxide. Azo compounds that may be used include, but are not limited to: 2,2 '-azobis (isobutyronitrile), 2' -azobis (2, 4-dimethylvaleronitrile). Among them, sodium Persulfate (SPS), potassium persulfate (KPS), ammonium Persulfate (APS), 2 '-azobis (amidinopropyl) dihydrochloride (AIBA, V-50. TM.) and 4,4' -azobis (4-cyanovaleric acid) (ACVA, V501) are preferable as the thermal initiator.

Redox initiators generally comprise an oxidizing agent and a reducing agent. Suitable oxidizing agents include the peroxides described above. Suitable reducing agents may be alkali metal sulfites, such as potassium sulfite and/or sodium sulfite; or alkali metal bisulfites such as potassium and/or sodium bisulfites. Preferred redox initiators include oxidizing agents selected from t-butyl hydroperoxide and hydrogen peroxide, and reducing agents selected from ascorbic acid, sodium formaldehyde sulfoxylate, sodium acetone bisulfite, and sodium metabisulfite (sodium bisulfite).

The polymerization may be carried out and maintained at a temperature of less than 100 ℃ throughout the reaction. Preferably, the polymerization is carried out at a temperature between 60 ℃ and 95 ℃. Depending on the various polymerization conditions, the polymerization may be carried out for several hours, for example from 2 to 8 hours.

The organic base and/or inorganic base may be added to the polymerization system as a neutralizing agent during the polymerization or after completion of the process. Suitable neutralizing agents include, but are not limited to: an inorganic base such as ammonia, sodium hydroxide/potassium hydroxide, sodium carbonate/potassium carbonate, or any combination thereof. Organic bases such as dimethylamine, diethylamine, triethylamine, monoethanolamine, triethanolamine, or mixtures thereof can also be used as neutralizing agents. Among them, sodium hydroxide, ammonia, dimethylaminoethanol, 2-amino-2-methyl-1-propanol, or any mixture thereof is preferable as the neutralizing agent usable in the polymerization process. After addition of the neutralizing agent, the pH of the final polymer emulsion should be in the range of 6.0 to 10.0, preferably in the range of 7.0 to 9.5, more preferably in the range of 7.0 to 9.0.

The average particle size of the polymer particles dispersed in the aqueous dispersion is preferably less than 300nm, in particular less than 250nm. Particularly preferably, the average particle diameter lies between 50 and 200 nm.

The solids content of the aqueous multistage copolymer dispersion of the present invention may be in the range of from 10 to 70 wt%, preferably from 20 to 60 wt%, more preferably from 30 to 60 wt% and most preferably from 40 to 60 wt%.

The inventionThe clear aqueous multistage polymer emulsion may be formulated with pigments, emulsifiers, buffers, neutralizing agents, rheology modifiers, humectants, wetting agents, biocides, plasticizers, defoamers, colorants, waxes, antioxidants, and other materials for preparing coating compositions. The formulation is not particularly limited, and common formulations known to those skilled in the art, such as those disclosed in US20090149591A1, US20140235752A1, WO2012021826A2, and the like, may be applied. Suitable pigments include, but are not limited to, zinc oxide, antimony oxide, zirconium oxide, titanium dioxide, and Ropaque ^TM Opaque polymers (Rohm and Haas co., philiadelphia, pa., USA). Suitable emulsifiers include, but are not limited to: alkali metal or ammonium salts of alkyl sulfates, alkyl sulfonic acids, fatty acids, nonylphenol ethoxylates, sodium dodecylbenzenesulfonate, sodium dodecylsulfonate, triton ^TM Or Igepal ^TM Or Rhodapon ^TM Those sold. Suitable rheology modifiers include, but are not limited to: starch and cellulose derivatives, alkali swellable acrylic thickeners, materials sold under the trade name ACRYSOL. Suitable defoamers include, but are not limited to: the commodity name is

Colloid and/>

And->

Is a material of (3). Suitable biocides include, but are not limited to: under the trade name Nuosept ^TM And->

Is a compound of (a).

The aqueous multistage polymer emulsions of the present invention can be formulated into coating compositions by various methods known to those skilled in the art. The preparation of the coating composition is not particularly preferred. For example, a suitable amount of pigment is dispersed in an aqueous medium at a high shear rate in a suitable mixer. The aqueous multistage polymer dispersion is then added to the dispersion by continuous feeding. At the same time, other necessary materials are also fed into the mixer, which may include emulsifiers, rheology modifiers, defoamers, plasticizers, colorants, waxes, antioxidants, and the like.

The invention will be further illustrated and exemplified in the examples, but is not limited to the embodiments described in the examples.

Examples

Description of commercially available materials used in the following examples:

RS-710: dispersants, phosphate esters, from Solvay (hereinafter referred to as RS-710).

PAM100: reactive surfactants, phosphate methacrylate derivatives, are derived from Solvay (hereinafter PAM 100).

FF6M: reducing agent, sodium salt of organic sulfinic acid derivative, from Brucggemann Chemical (hereinafter referred to as FF 6M).

DB45: diphenyl oxide disulfonate anionic surfactant from Pilot Chemical Company (hereinafter referred to as DB 45).

24T: phosphate surfactants from BASF.

LDBS23: alkylbenzene sulfonate tableSurfactants from BASF.

ADEKA Resoap SR-1025: the reaction product of a surfactant, ethylene oxide [ (2-propenoxy) methyl ] with a C10-14 branched alcohol, ethylene oxide, and sulfamic acid is from ADEKA CORPORATION, japan (hereinafter SR 1025).

All experiments described below were performed at a temperature of 20 ℃, unless otherwise indicated.

Example 1 (invention):

the first stage mixture pre-emulsion was prepared by the following procedure: 13.6g of SR1025, 8.4g of RS710, 5.2g of PAM100, 763.2g of Butyl Acrylate (BA), 252.2g of Styrene (ST), 16.8g of Acrylic Acid (AA), 44.2g of acrylamide solution (Am, 30% by weight aqueous solution) and 518.7g of deionized water were mixed in a vessel and then emulsified by stirring at 500rpm for 10 minutes using a magnetic stirring bar.

The pre-emulsion of the second stage mixture was prepared by the following procedure: 62.5g of Butyl Acrylate (BA), 150.2g of Styrene (ST), 26.4g of Glycidyl Methacrylate (GMA), 7.2g of SR1025, 4.5g of RS710 and 157.9g of deionized water were mixed in a vessel and then stirred using a magnetic stirring bar at 500rpm for 10 minutes for emulsification.

5.25g of SR1025 and 401.4g of water were charged under a nitrogen atmosphere into a four liter multi-necked flask equipped with a mechanical stirring device. The mixture was heated to a temperature of 90 ℃ under a nitrogen atmosphere, and this condition was maintained in the following operation unless otherwise indicated. 71.4g of the pre-emulsion of the first stage monomer (first part) and 20.8g of sodium persulfate (SPS, 4.1 wt% aqueous solution) were added in parallel to the flask with stirring over 2 minutes. Five minutes after the first portion was added, the remaining pre-emulsion of the first stage monomer was fed over 120 minutes. Then, a pre-emulsion of the second stage monomer was added over 30 minutes. Separately, once the addition of the second part of the first stage monomer was started, the feed of 73.5g SPS (4.1 wt% aqueous solution) was started for 150 minutes. After the SPS feed was completed for 30 minutes, the reaction temperature was lowered to 55 ℃ and 6.47g of ammonia solution (20 wt% aqueous solution) and 10.4g of NaOH solution (8 wt% aqueous solution) were added to neutralize the system. However, the method is that After that, 23.0. 23.0g t-BHP (10 wt% aqueous solution) and 45.4g FF6M (10 wt% aqueous solution) were added in parallel over 90 minutes. After completion of the feeding of t-BHP and FF6M, the reaction mixture was cooled to 20 ℃ and neutralized with aqueous NaOH to ph=8. Finally, biocide (2.7 g

MV and 8.7 g->

MBS, all from THOR, germany) was added to the mixture.

The resulting aqueous polymer emulsion had a pH of 8, a solids content of 49% by weight and a particle size of 156nm.

Example 2 (invention):

the pre-emulsion of the first stage mixture was prepared by the following procedure: 7.5g of DB45, 8.4g of Maphos24T, 5.1g of PAM100, 64.3g of acrylamide solution (Am, 30% by weight aqueous solution), 16.8g of Acrylic Acid (AA), 606.8g of Butyl Acrylate (BA), 139.2g of Styrene (ST) and 514.3g of deionized water were mixed in a vessel and then stirred at 500rpm for 10 minutes using a magnetic stirring bar for emulsification.

Pre-emulsion 2 was prepared by the following procedure: 4.0g of DB45, 4.5g of Maphos24T, 54.4g of acetoacetoxyethyl methacrylate (AAEMA), 214.2g of Butyl Acrylate (BA) and 257.7g of Styrene (ST) and 156.6g of deionized water were mixed in a vessel and then stirred at 500rpm for 10 minutes using a magnetic stirring bar for emulsification.

Under the protection of nitrogen atmosphere, 5.7g of

LDBS23, 0.33g of copper sulfate solution (0.1 wt% aqueous solution) and 398g of deionized water were charged into a four liter multi-necked flask equipped with a mechanical stirring device. The mixture was heated to a temperature of 90 ℃ under a nitrogen atmosphere, and this condition was maintained in the following operation unless otherwise indicated. 79.2g of the pre-emulsion of the first stage monomer (first part) and 20.7g of sodium persulfate (SPS, 4.1% by weight in water) were leveled with stirring over 2 minutesAdded to the flask in rows. Five minutes after the first portion was added, the remaining pre-emulsion of the first stage monomer was fed over 90 minutes. Then, a pre-emulsion of the second stage monomer was added over 60 minutes. Separately, once the addition of the second part of the first stage monomer was started, a feed of 72.9g SPS (4.1 wt% aqueous solution) was started, which feed lasted 150 minutes. After the SPS feed was completed for 30 minutes, the reaction temperature was reduced to 75 ℃ and 6.5g of ammonia solution (20 wt% aqueous solution) was added to neutralize the system. Then, 7.7. 7.7g t-BHP (10 wt% aqueous solution) and 9.8g of sodium acetone bisulfite (SAB, 13 wt% aqueous solution) were added in parallel over 90 minutes. After completion of the feeding of t-BHP and SAB, the reaction mixture was cooled to 20 ℃ and neutralized with aqueous NaOH to ph=8. Finally, biocide (2.7 g +. >

MV and 8.7 g->

MBS, all from THOR, germany) was added to the mixture.

The resulting aqueous polymer emulsion had a pH of 8, a solids content of 49% by weight and a particle size of 130nm.

Example 3 (invention):

the pre-emulsion of the first stage mixture was prepared by the following procedure: 16.7g of SR1025, 9.8g of RS710, 5.1g of PAM100, 45.7g of acrylamide solution (Am, 30 wt% aqueous solution), 10.7g of Acrylic Acid (AA), 19.4g of Glycidyl Methacrylate (GMA), 632.7g of Butyl Acrylate (BA), 343.7g of Styrene (ST) and 524.6g of deionized water were mixed in a vessel and then emulsified by stirring at 500rpm for 10 minutes using a magnetic stirring bar.

The pre-emulsion of the second stage mixture was prepared by the following procedure: 1.5g of SR1025, 7.0g of RS710, 5.7g of Acrylic Acid (AA), 16.3g of Glycidyl Methacrylate (GMA), 192.7g of Butyl Acrylate (BA), 35.2g of Styrene (ST) and 159.7g of deionized water were mixed in a vessel and then stirred at 500rpm for 10 minutes using a magnetic stirring bar for emulsification.

5.3g SR1025 and 405.9g water were charged to a four liter multi-necked flask equipped with a mechanical stirring device under a nitrogen atmosphere. The mixture was heated to a temperature of 90 ℃ under a nitrogen atmosphere, and this condition was maintained in the following operation unless otherwise indicated. 72.2g of a pre-emulsion of the first stage monomer (first part) and 21.1g of sodium persulfate (SPS, 4.1 wt% aqueous solution) were added in parallel to the flask with stirring over 2 minutes. Five minutes after the first portion was added, the remaining pre-emulsion of the first stage monomer was fed over 120 minutes. After the completion of the feeding of the first stage monomer, the reaction was kept as it is for 30 minutes. Then, the addition of the pre-emulsion of the second stage monomer was started and completed within 30 minutes. Separately, once the addition of the second part of the first stage monomer was started, the feed of 74.3g SPS (4.1 wt% aqueous solution) was started. SPS feed was first continued for 120 minutes, then paused for 30 minutes, then continued for another 30 minutes. After the SPS feed was completed for 30 minutes, the reaction temperature was reduced to 55 ℃ and 39.9g NaOH solution (8 wt% aqueous solution) was added to neutralize the system. Then, 23.2. 23.2g t-BHP (10 wt% aqueous solution) and 45.4g FF6M (10 wt% aqueous solution) were added in parallel over 90 minutes. After completion of the feeding of t-BHP and FF6M, the reaction mixture was cooled to 20 ℃ and neutralized with aqueous NaOH to ph=8. Finally, biocide (2.7 g

MV and 8.7 g->

MBS, all from THOR, germany) was added to the mixture.

The aqueous multistage polymer emulsion obtained had a pH of 8, a solids content of 47% by weight and a particle size of 150nm.

Example 4 (invention):

the pre-emulsion of the first stage mixture was prepared by the following procedure: 16.6g of SR1025, 0.08g of RS710, 5.1g of PAM100, 55.5g of acrylamide solution (Am, 30 wt% aqueous solution), 12.0g of Acrylic Acid (AA), 24.8g of Glycidyl Methacrylate (GMA), 670.6g of Butyl Acrylate (BA), 266.7g of Styrene (ST) and 524.6g of deionized water were mixed in a vessel and then stirred at 500rpm for 10 minutes using a magnetic stirring bar for emulsification.

The pre-emulsion of the second stage mixture was prepared by the following procedure: 1.0g of SR1025, 6.4g of RS710, 4.2g of Acrylic Acid (AA), 18.7g of Glycidyl Methacrylate (GMA), 105.7g of Butyl Acrylate (BA), 150.5g of Styrene (ST) and 159.7g of deionized water were mixed in a vessel and then stirred at 500rpm for 10 minutes using a magnetic stirring bar for emulsification.

5.3g SR1025 and 405.9g water were charged to a four liter multi-necked flask equipped with a mechanical stirring device under a nitrogen atmosphere. The mixture was heated to a temperature of 90 ℃ under a nitrogen atmosphere, and this condition was maintained in the following operation unless otherwise indicated. 72.2g of a pre-emulsion of the first stage monomer (first part) and 21.1g of sodium persulfate (SPS, 4.1 wt% aqueous solution) were added in parallel to the flask with stirring over 2 minutes. Five minutes after the first portion was added, the remaining pre-emulsion of the first stage monomer was fed over 120 minutes. After the completion of the feeding of the first stage monomer, the reaction was kept as it is for 30 minutes. Then, the addition of the pre-emulsion of the second stage monomer was started and completed within 30 minutes. Separately, once the addition of the second part of the first stage monomer was started, the feed of 74.3g SPS (4.1 wt% aqueous solution) was started. SPS feed was first continued for 120 minutes, then paused for 30 minutes, then continued for another 30 minutes. After the SPS feed was completed for 30 minutes, the reaction temperature was reduced to 55 ℃ and 39.9g NaOH solution (8 wt% aqueous solution) was added to neutralize the system. Then, 23.2. 23.2g t-BHP (10 wt% aqueous solution) and 45.4g FF6M (10 wt% aqueous solution) were added in parallel over 90 minutes. After completion of the feeding of t-BHP and FF6M, the reaction mixture was cooled to 20 ℃ and neutralized with aqueous NaOH to ph=9. Finally, biocide (2.7 g

MV and 8.7 g->

MBS all fromTHOR, germany) was added to the mixture.

The resulting aqueous polymer emulsion had a pH of 9, a solids content of 48% by weight and a particle size of 156nm.

Example 5 (invention):

the pre-emulsion of the first stage mixture was prepared by the following procedure: 13.4g of SR1025, 8.4g of RS710, 5.1g of PAM100, 43.7g of acrylamide solution (Am, 30 wt% aqueous solution), 16.7g of Acrylic Acid (AA), 754.7g of Butyl Acrylate (BA), 249.4g of Styrene (ST) and 512.9g of deionized water were mixed in a vessel and then stirred at 500rpm for 10 minutes using a magnetic stirring bar for emulsification.

The pre-emulsion of the second stage mixture was prepared by the following procedure: 7.4g of SR1025, 4.5g of RS710, 54.2g of acetoacetoxyethyl methacrylate, 61.8g of Butyl Acrylate (BA), 148.6g of Styrene (ST) and 156.2g of deionized water were mixed in a vessel and then stirred using a magnetic stirring bar at 500rpm for 10 minutes for emulsification.

5.2g of SR1025 and 396.9g of water were charged under a nitrogen atmosphere into a four liter multi-necked flask equipped with a mechanical stirring device. The mixture was heated to a temperature of 90 ℃ under a nitrogen atmosphere, and this condition was maintained in the following operation unless otherwise indicated. 70.6g of a pre-emulsion of the first stage monomer (first part) and 20.6g of sodium persulfate (SPS, 4.1 wt% aqueous solution) were added in parallel to the flask with stirring over 2 minutes. Five minutes after the first portion was added, the remaining pre-emulsion of the first stage monomer was fed over 120 minutes. Then, the addition of the pre-emulsion of the second stage monomer was started and completed within 30 minutes. Separately, once the addition of the second part of the first stage monomer was started, the feed of 72.7g SPS (4.1 wt% aqueous solution) was started for 150 minutes. After the SPS feed was completed for 30 minutes, the reaction temperature was reduced to 75 ℃ and 6.5g of ammonia solution (20 wt% aqueous solution) was added to neutralize the system. Then, 22.7. 22.7g t-BHP (10 wt% aqueous solution) and 30.4g SAB (13 wt% aqueous solution) were added in parallel over 90 minutes. After completion of the feeding of t-BHP and SAB, the reaction mixture was cooled to 20 ℃ and neutralized with aqueous NaOH to ph=8. Finally, it will kill Agent (2.7 g)

MV and 8.7 g->

MBS, all from THOR, germany) was added to the mixture. />

The aqueous multistage polymer emulsion obtained had a pH of 8, a solids content of 49% by weight and a particle size of 166nm.

Example 6 (control):

the pre-emulsion of the first stage mixture was prepared by the following procedure: 16.8g of SR1025, 8.9g of RS710, 5.1g of PAM100, 34.2g of acrylamide solution (Am, 30 wt% aqueous solution), 12.4g of Acrylic Acid (AA), 32.2g of Glycidyl Methacrylate (GMA), 735.1g of Butyl Acrylate (BA), 154.1g of Styrene (ST) and 524.6g of deionized water were mixed in a vessel and then stirred at 500rpm for 10 minutes using a magnetic stirring bar for emulsification.

The pre-emulsion of the second stage mixture was prepared by the following procedure: 1.8g of SR1025, 6.4g of RS710, 5.2g of Acrylic Acid (AA), 24.4g of Glycidyl Methacrylate (GMA), 193.2g of Butyl Acrylate (BA), 103.0g of Styrene (ST) and 159.7g of deionized water were mixed in a vessel and then stirred at 500rpm for 10 minutes using a magnetic stirring bar for emulsification.

5.3g SR1025 and 405.9g water were charged to a four liter multi-necked flask equipped with a mechanical stirring device under a nitrogen atmosphere. The mixture was heated to a temperature of 90 ℃ under a nitrogen atmosphere, and this condition was maintained in the following operation unless otherwise indicated. 72.2g of a pre-emulsion of the first stage monomer (first part) and 21.1g of sodium persulfate (SPS, 4.1 wt% aqueous solution) were added in parallel to the flask with stirring over 2 minutes. Five minutes after the first portion was added, the remaining pre-emulsion of the first stage monomer was fed over 120 minutes. After the completion of the feeding of the first stage monomer, the reaction was kept as it is for 30 minutes. Then, the addition of the pre-emulsion of the second stage monomer was started and completed within 30 minutes. Separately, once the addition of the first stage monomer has begun Then a feed of 74.3g SPS (4.1 wt% aqueous solution) was started. SPS feed was first continued for 120 minutes, then paused for 30 minutes, then continued for another 30 minutes. After the SPS feed was completed for 30 minutes, the reaction temperature was reduced to 55 ℃ and 39.9g NaOH solution (8 wt% aqueous solution) was added to neutralize the system. Then, 23.2. 23.2g t-BHP (10 wt% aqueous solution) and 45.9g FF6M (10 wt% aqueous solution) were added in parallel over 90 minutes. After completion of the feeding of t-BHP and FF6M, the reaction mixture was cooled to 20 ℃ and neutralized with aqueous NaOH to ph=7. Finally, biocide (2.7 g

MV and 8.7 g->

MBS, all from THOR, germany) was added to the mixture.

The aqueous multistage polymer emulsion obtained had a pH of 7, a solids content of 48% by weight and a particle size of 155nm.

Example 7 (control):

the pre-emulsion of the first stage mixture was prepared by the following procedure: 3.2g of SR1025, 2.0g of RS710, 8.8g of acrylamide solution (Am, 30 wt% aqueous solution), 3.4g of Acrylic Acid (AA), 26.4g of Glycidyl Methacrylate (GMA), 62.5g of Butyl Acrylate (BA), 150.2g of Styrene (ST) and 157.9g of deionized water were mixed in a vessel, and then stirred at 500rpm for 10 minutes using a magnetic stirring bar for emulsification.

The pre-emulsion of the second stage mixture was prepared by the following procedure: 17.6g of SR1025, 10.5g of RS710, 5.2g of PAM100, 763.2g of Butyl Acrylate (BA), 252.2g of Styrene (ST), 35.3g of acrylamide solution (Am, 30 wt% aqueous solution), 13.5g of Acrylic Acid (AA) and 518.7g of deionized water were mixed in a vessel and then emulsified by stirring at 500rpm for 10 minutes using a magnetic stirring bar.

5.25g of SR1025 and 401.4g of water were charged under a nitrogen atmosphere into a four liter multi-necked flask equipped with a mechanical stirring device. The mixture was heated to a temperature of 90℃under a nitrogen atmosphere andand this condition is maintained in the following operation unless otherwise specified. 79.5g of the pre-emulsion of the first stage monomer (first part) and 20.8g of sodium persulfate (SPS, 4.1 wt% aqueous solution) were added in parallel to the flask with stirring over 2 minutes. Five minutes after the first portion was added, the remaining pre-emulsion of the first stage monomer was fed over 120 minutes. Then, a pre-emulsion of the second stage monomer was added over 30 minutes. Separately, once the addition of the second part of the first stage monomer was started, the feed of 73.5g SPS (4.1 wt% aqueous solution) was started. SPS feed was first continued for 120 minutes, then paused for 30 minutes, then continued for another 30 minutes. 30 minutes after SPS feed was completed, the reaction temperature was lowered to 55℃and 6.47g of ammonia solution (20% by weight aqueous solution) and 10.4g of NaOH solution (8% by weight aqueous solution) were added to neutralize the system. Then, 23.0. 23.0g t-BHP (10 wt% aqueous solution) and 45.4g FF6M (10 wt% aqueous solution) were added in parallel over 90 minutes. After completion of the feeding of t-BHP and FF6M, the reaction mixture was cooled to 20 ℃ and neutralized with aqueous NaOH to ph=8. Finally, biocide (2.7 g

MV and 8.7 g->

MBS, all from THOR, germany) was added to the mixture.

The aqueous multistage polymer emulsion obtained had a pH of 8, a solids content of 49% by weight and a particle size of 169nm.

Example 8 (control):

the pre-emulsion of the first stage mixture was prepared by the following procedure: 12.9g of SR1025, 11.6g of RS710, 5.0g of PAM100, 53.0g of acrylamide solution (Am, 30 wt% aqueous solution), 15.1g of Acrylic Acid (AA), 0.0014g of Glycidyl Methacrylate (GMA), 587.2g of Butyl Acrylate (BA), 231.5g of Styrene (ST) and 524.6g of deionized water were mixed in a vessel and then stirred at 500rpm for 10 minutes using a magnetic stirring bar for emulsification.

The pre-emulsion of the second stage mixture was prepared by the following procedure: 1.0g of SR1025, 7.7g of RS710, 0.7g of Acrylic Acid (AA), 26.0g of Glycidyl Methacrylate (GMA), 252.9g of Butyl Acrylate (BA), 140.7g of Styrene (ST) and 159.7g of deionized water were mixed in a vessel and then stirred at 500rpm for 10 minutes using a magnetic stirring bar for emulsification.

5.3g SR1025 and 405.9g water were charged to a four liter multi-necked flask equipped with a mechanical stirring device under a nitrogen atmosphere. The mixture was heated to a temperature of 90 ℃ under a nitrogen atmosphere, and this condition was maintained in the following operation unless otherwise indicated. 72.2g of a pre-emulsion of the first stage monomer (first part) and 21.1g of sodium persulfate (SPS, 4.1 wt% aqueous solution) were added in parallel to the flask with stirring over 2 minutes. Five minutes after the first portion was added, the remaining pre-emulsion of the first stage monomer was fed over 120 minutes. After the completion of the feeding of the first stage monomer, the reaction was kept as it is for 30 minutes. Then, the addition of the pre-emulsion of the second stage monomer was started and completed within 30 minutes. Separately, once the addition of the second part of the first stage monomer was started, the feed of 74.3g SPS (4.1 wt% aqueous solution) was started. SPS feed was first continued for 120 minutes, then paused for 30 minutes, then continued for another 30 minutes. After the SPS feed was completed for 30 minutes, the reaction temperature was reduced to 55 ℃ and 39.9g NaOH solution (8 wt% aqueous solution) was added to neutralize the system. Then, 23.2. 23.2g t-BHP (10 wt% aqueous solution) and 45.9g FF6M (10 wt% aqueous solution) were added in parallel over 90 minutes. After completion of the feeding of t-BHP and FF6M, the reaction mixture was cooled to 20 ℃ and neutralized with aqueous NaOH to ph=8. Finally, biocide (2.7 g

MV and 8.7 g->

MBS, all from THOR, germany) was added to the mixture.

The resulting aqueous multistage polymer emulsion had a pH of 8, a solids content of 47% by weight and a particle size of 165nm.

Example 9 (control):

the pre-emulsion mixture was prepared by the following procedure: 11.5g of DB45, 13.0g of Maphos 24T, 5.2g of PAM100, 65.0g of acrylamide solution (Am, 30% by weight aqueous solution), 16.9g of Acrylic Acid (AA), 25.5g of Glycidyl Methacrylate (GMA), 725.5g of butyl acrylate, 505.7g of Styrene (ST) and 678.3g of deionized water were mixed in a vessel and then stirred at 500rpm for 10 minutes using a magnetic stirring bar for emulsification.

Under the protection of nitrogen atmosphere, 5.7g of

LDBS23, 0.33g of copper sulfate solution (0.1 wt% aqueous solution) and 398g of deionized water were charged into a four liter multi-necked flask equipped with a mechanical stirring device. The mixture was heated to a temperature of 90 ℃ under a nitrogen atmosphere, and this condition was maintained in the following operation unless otherwise indicated. 66.5g of the pre-emulsion of the first stage monomer (first part) and 20.7g of sodium persulfate (SPS, 4.1 wt% aqueous solution) were added in parallel to the flask with stirring over 2 minutes. Five minutes after the first portion was added, the remaining pre-emulsion of the first stage monomer was fed over 90 minutes. Then, a pre-emulsion of the second stage monomer was added over 60 minutes. Separately, once the addition of the second part of the first stage monomer was started, the feed of 72.9g SPS (4.1 wt% aqueous solution) was started. SPS feed was first continued for 120 minutes, then paused for 30 minutes, then continued for another 30 minutes. After the SPS feed was completed for 30 minutes, the reaction temperature was reduced to 75 ℃ and 6.5g of ammonia solution (20 wt% aqueous solution) was added to neutralize the system. Then, 7.7. 7.7g t-BHP (10 wt% aqueous solution) and 9.8g SAB (13 wt% aqueous solution) were added in parallel over 90 minutes. After completion of the feeding of t-BHP and SAB, the reaction mixture was cooled to 20 ℃ and neutralized with aqueous NaOH to ph=8. Finally, biocide (2.7 g +. >

MV and 8.7g

MBS, all from THOR, germany) is added to the mixture.

The resulting aqueous multistage polymer emulsion had a pH of 8, a solids content of 49% by weight and a particle size of 144nm.

Method for preparing and testing paint

130g deionized water, 6.5g Dispex AA 4140 (from BASF), 1.5g Dispex ultra FA4480 (from BASF), 2g Foamstar ST2410 AC (from BASF), 3g Natrosol 250HBR (from Ashland), 2g Silres bs168 (from Wacker), 220g Lomon r996 (from Lomon), 110g Omyacarb 2 (from Omya), and 60g DB-80 (from Bright Industrial co.) were first prepared into flasks. Then, 1g of Kathon LX150 (from Dow), acticide MBS (from Thor) containing 81.5g of deionized water was added followed by 324.32g of the polymer emulsion prepared as above, 1.5g Foamstar ST 2410AC (from BASF), 1.5g Dispex ultra FA4480 (from BASF), 5.8g Rheovis HS 1212 (50 wt% aqueous solution from BASF), 1.67g Rheovis PU1291 (50 wt% aqueous solution from BASF) and 46.71g of deionized water. The pigment volume concentration of the resulting coating was 43%.

DPUR and acid resistance tests were carried out according to the procedures and standards established in GB/T9780 2013. Step 6 has been followed for the tests of DPUR and acid resistance properties. DPUR performance was evaluated using only the test score (R value) for petrolatum carbon black, and a score of at least 6 points was considered acceptable. Only the test score (R value) for vinegar was used to evaluate acid resistance, with at least 6 points considered acceptable.

The Low Temperature Film Flexibility (LTFF) test was performed as follows: each of the paints obtained in the above steps was brushed on an A4-sized putty plate. And the coating was uniformly applied to the panels (i.e., the coating thickness was the same throughout the panel), each coated panel contained 40 grams of coating. The coated plate was then placed in a refrigerator at a temperature of 5 ℃ for 12 hours. Finally, the panels were inspected by visual inspection immediately after removal from the refrigerator. If the panel does not show significant cracking, it will be rated as "pass"; otherwise, it will be rated as "failed". For the present invention, a rating of "pass" is required.

The average particle diameter of the copolymer particles referred to herein is referred to as the Z-average particle diameter as determined by Dynamic Light Scattering (DLS) method. The measurement method is described in ISO 13321:1996 standard. For this purpose, a sample of the aqueous copolymer dispersion is diluted and the resulting aqueous dilution is analyzed. In the case of DLS, the aqueous diluent may have a polymer concentration in the range of 0.001 wt% to 0.5 wt% depending on the particle size. For most purposes, a suitable concentration is 0.01% by weight. However, higher or lower concentrations may be used to obtain the best signal-to-noise ratio. To avoid flocculation, dilution may be achieved by adding the aqueous copolymer dispersion to water or to an aqueous solution of surfactant. Typically, dilution is performed by using a 0.1 wt% aqueous solution of a nonionic emulsifier (e.g., an ethoxylated C16/C18 alkanol (18 degree of ethoxylation)) as the diluent.

Measurement configuration: high Performance Particle Sizer (HPPS), from Malvern Instruments, UK, automated with continuous flow cell and Gilson autosampler.

Parameters: measuring the temperature to 20.0 ℃; measurement time 120 seconds (6 cycles, 20s each); scattering angle 173; a laser wavelength 633nm (HeNe); refractive index of the medium 1.332 (water); the viscosity was 0.9546 mPas.

The measurement gives the average of the second order cumulant analysis (fitted average), i.e. Z-average. The "fitted average" is the mean, intensity weighted hydrodynamic particle size in nm.

The results of DPUR, acid resistance and Low Temperature Film Flexibility (LTFF) are listed in Table 1.

Examples 1 to 5 are working examples, which demonstrate that polymer emulsions with properly controlled total Fox Tg (Tg 0), Δtg and weight ratio of first stage polymer to second stage polymer show better performance. In contrast, examples 6 to 9 are regarded as failed examples because at least one requirement is not satisfied.

TABLE 1

However, the invention is not limited in scope to the specific embodiments and examples described herein. Indeed, various modifications of the invention in addition to those described herein will be apparent to those skilled in the art from the foregoing description. Such modifications are intended to fall within the scope of the appended claims.

Claims

1. An aqueous multistage polymer emulsion wherein the total calculated Fox Tg (Tg 0) of the polymer is in the range of-10 ℃ to +5 ℃, the calculated difference (Δtg) between the Fox Tg (Tg 2) of the second stage and the Fox Tg (Tg 1) of the first stage is in excess of 10 ℃, and the weight ratio of the first stage polymer to the second stage polymer is in the range of 95:5 to 30:70, based on the total amount of monomers used for polymerization of each stage;

wherein the monomers used in the first stage and the second stage each independently comprise:

(A) At least one hydrophobic monoethylenically unsaturated monomer (a), the total amount of hydrophobic monoethylenically unsaturated monomers may be at least 80% by weight;

(B) At least one hydrophilic monoethylenically unsaturated monomer (b), the total amount of hydrophilic monoethylenically unsaturated monomers may be at least 0.1% by weight and not more than 20% by weight;

wherein the polymer emulsion comprises from 0.1 wt% to 6 wt% surfactant based on the total weight of the monomers.

2. The aqueous multistage polymer emulsion of claim 1, the total amount of hydrophobic monoethylenically unsaturated monomers may be at least 85% by weight.

3. The aqueous multistage polymer emulsion of claim 1, the total amount of hydrophobic monoethylenically unsaturated monomers may be at least 90 wt%.

4. The aqueous multistage polymer emulsion of claim 1, the total amount of hydrophobic monoethylenically unsaturated monomers may be at least 95% by weight.

5. The aqueous multistage polymer emulsion of claim 1, the total amount of hydrophilic monoethylenically unsaturated monomers may be at least 0.1 wt% and not more than 15 wt%.

6. The aqueous multistage polymer emulsion of claim 1, the total amount of hydrophilic monoethylenically unsaturated monomers may be at least 0.1 wt% and not more than 10 wt%.

7. The aqueous multistage polymer emulsion of claim 1, the total amount of hydrophilic monoethylenically unsaturated monomers may be at least 0.1 wt% and not more than 5 wt%.

8. The aqueous multistage polymer emulsion according to claim 2, wherein the monomers for the first stage and/or the second stage further comprise one or more crosslinking monomers (c).

9. The aqueous multistage polymer emulsion of claim 8, wherein the crosslinking monomer (c) is added in an amount of not more than 10 wt%, based on the total weight of all monomers used for polymer synthesis.

10. The aqueous multistage polymer emulsion according to claim 9, wherein the crosslinking monomer (c) is added in an amount of not more than 8% by weight based on the total weight of all monomers used for polymer synthesis.

11. The aqueous multistage polymer emulsion according to claim 9, wherein the crosslinking monomer (c) is added in an amount of not more than 5% by weight based on the total weight of all monomers used for polymer synthesis.

12. The aqueous multistage polymer emulsion according to any one of claims 1 to 9, wherein the total calculated Fox Tg (Tg 0) is in the range of-10 ℃ to 0 ℃.

13. The aqueous multistage polymer emulsion according to any one of claims 1 to 9, wherein the calculated difference (Δtg) between the Fox Tg of the second stage (Tg 2) and the Fox Tg of the first stage (Tg 1) exceeds 15 ℃.

14. The aqueous multistage polymer emulsion of any one of claims 1 to 9, wherein the weight ratio of first stage polymer to second stage polymer is in the range of 95:5 to 40:60.

15. The aqueous multistage polymer emulsion of claim 14, wherein the weight ratio of first stage polymer to second stage polymer is in the range of 90:10 to 40:60.

16. The aqueous multistage polymer emulsion of claim 14, wherein the weight ratio of first stage polymer to second stage polymer is in the range of 90:10 to 50:50.

17. The aqueous multistage polymer emulsion according to any one of claims 1 to 9, wherein the particle size of the emulsion is in the range of 50-300 nm.

18. The aqueous multistage polymer emulsion of claim 17, wherein the emulsion has a particle size in the range of 50-250 nm.

19. The aqueous multistage polymer emulsion of claim 17, wherein the emulsion has a particle size in the range of 50-200 nm.

20. A method of preparing the aqueous multistage polymer emulsion of any one of claims 1 to 19, comprising:

step 1: polymerizing the first stage polymer;

step 2: the second stage polymer is then polymerized.

21. A coating comprising the aqueous multistage polymer emulsion of any one of claims 1 to 19, or obtained by the method of claim 20.