JP6701648B2 - Composite polymer particles and method for producing the same - Google Patents

Description

The present invention relates to composite polymer particles composed of a fluoropolymer and an acrylic polymer and a method for producing the same.

Patent Document 1 discloses that in order to provide an aqueous polymer dispersion in which the drawbacks of the fluoropolymer are improved while maintaining the original excellent performance of the fluoropolymer, the fluoropolymer in an aqueous medium is used. A method for producing an aqueous polymer dispersion is described, in which the polymer is used as a seed polymer and the ethylenically unsaturated monomer is emulsion-polymerized in the presence of these fluoropolymer particles.

In Patent Document 2, a fluoropolymer (A) is dissolved in an ethylenically unsaturated group-containing monomer (b), and the obtained polymer solution is subjected to emulsion polymerization. A method of making an aqueous dispersion of particles is described.

In Patent Document 3, a fluoropolymer (A) is dissolved in an ethylenically unsaturated group-containing monomer (b) to prepare a polymer solution (I), and the polymer solution is used to prepare an ethylenic An emulsion polymerization step of emulsion-polymerizing a saturated group-containing monomer (b) to produce an aqueous dispersion of fluorine-containing composite polymer particles (II), and an aqueous dispersion of the fluorine-containing composite polymer particles (II). A composite including an impregnation polymerization step of polymerizing the ethylenically unsaturated group-containing monomer (c) while adding the ethylenically unsaturated group-containing monomer (c) and impregnating it into the fluorine-containing composite polymer particles (II). A method of making an aqueous dispersion of particles (III) is described.

JP-A-62-32102 International Publication No. 2007/15477 JP, 2009-242479, A

However, there is a demand for composite polymer particles capable of forming a clear coating film that is more excellent in initial water resistance, blocking resistance and transparency than conventional composite polymer particles.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a composite polymer particle capable of forming a coating film having excellent initial water resistance, blocking resistance, and transparency.

Another object of the present invention is to provide a method for producing composite polymer particles capable of forming a coating film having excellent initial water resistance, blocking resistance and transparency in view of the above-mentioned current situation.

In the present invention, the fluoropolymer (A) and the acrylic polymer (B) are contained in the same particle, and the differential value peak intensity calculated from the differential scanning calorimetry curve obtained by the differential scanning calorimetry is 2.2×10 ^−. It is a composite polymer particle characterized by being ² mW/° C. or less.

The fluoropolymer (A) preferably contains vinylidene fluoride units.

The fluoropolymer (A) preferably contains a vinylidene fluoride unit and at least one fluoroolefin unit selected from the group consisting of tetrafluoroethylene, hexafluoropropylene and chlorotrifluoroethylene.

The acrylic polymer (B) preferably contains at least one acrylic monomer unit selected from the group consisting of acrylic acid, acrylic acid ester, methacrylic acid and methacrylic acid ester.

The acrylic polymer (B) preferably contains a methacrylic acid ester unit and at least one acrylic monomer unit selected from the group consisting of acrylic acid, methacrylic acid and acrylic acid ester.

The mass ratio (A/B) of the fluoropolymer (A) and the acrylic polymer (B) is preferably 10/90 to 75/25.

The present invention is also an aqueous dispersion containing the above-mentioned composite polymer particles.

The aqueous dispersion is preferably a paint.

The present invention is also a coating film obtained from the above aqueous dispersion.

The present invention is also a coated article comprising a substrate and a coating film obtained from the above aqueous dispersion.

The present invention comprises a step (1) of preparing an aqueous dispersion (1) containing particles of a fluoropolymer (A), an acrylic monomer being added to the aqueous dispersion (1), and at least the above-mentioned acrylic monomer added. The step (2) of obtaining an aqueous dispersion (2) containing intermediate particles by polymerizing the acrylic monomer until 95% by mass is consumed, and further, in the aqueous dispersion (2), the acrylic is added. The method for producing composite polymer particles also includes a step (3) of obtaining a composite polymer particle dispersed in the aqueous dispersion (3) by adding a monomer and polymerizing the acrylic monomer.

Since the composite polymer particle of the present invention has the above constitution, it is possible to form a coating film excellent in initial water resistance, blocking resistance and transparency.

Since the coating film and coated article of the present invention have the above-mentioned constitutions, they are excellent in initial water resistance, blocking resistance and transparency.

Since the production method of the present invention has the above constitution, it is possible to produce composite polymer particles capable of forming a coating film excellent in initial water resistance, blocking resistance and transparency.

FIG. 3 is a diagram showing a DSC curve of the composite polymer particles obtained in Example 4. FIG. 3 is a diagram showing a DSC curve of the composite polymer particles obtained in Comparative Example 1.

Hereinafter, the present invention will be specifically described.

The composite polymer particle of the present invention contains the fluoropolymer (A) and the acrylic polymer (B) in the same particle. The fluoropolymer (A) and acrylic polymer (B) are present in a single particle. In this respect, the aqueous dispersion containing the fluorine-containing composite polymer particles of the present invention is different from the aqueous dispersion formed by simply mixing the fluoropolymer (A) and the acrylic polymer (B). The fluoropolymer (A) and the acrylic polymer (B) are not chemically bonded.

The composite polymer particles of the present invention have a differential peak intensity calculated from a differential scanning calorimetry curve (hereinafter, also referred to as DSC curve) obtained by differential scanning calorimetry (hereinafter, also referred to as DSC (Differential scanning calorimetry)). It is characterized in that it is 2.2×10 ⁻² mW/° C. or less. FIG. 1 is a diagram showing a DSC curve of the composite polymer particles obtained in Example 4. Although the composite polymer particles include the fluoropolymer (A) and the acrylic polymer (B) in the above mass ratio, a gently sloping curve is obtained by DSC measurement, and a small differential peak intensity is obtained. Is calculated.

On the other hand, a clear baseline shift is recognized in the DSC curve of the fluoropolymer (A) or the acrylic polymer (B), and a large differential peak intensity is calculated. In the DSC curve of the composition obtained by mixing the fluoropolymer (A) and the acrylic polymer (B), an endothermic peak showing the melting point of the former and a baseline shift showing the glass transition temperature of the latter were observed, and a large differential The value peak intensity is calculated. Further, a clear baseline shift is also recognized in the DSC curve of the conventional composite polymer particle, and a large derivative peak intensity is calculated. FIG. 2 is a diagram showing a DSC curve of a conventional composite polymer particle obtained in Comparative Example 1. As is clear from FIG. 2, a clear baseline shift is recognized in the DSC curve of the conventional composite polymer particles.

The DSC is performed by the following method.
The measurement is performed using a differential scanning calorimeter (manufactured by METTLER TOLEDO, DSC822e, calculation software: STARe). The measurement method is to hold 10 mg of the sample at −50° C. for 8 minutes while purging with nitrogen at 40 to 50 ml/min, and then raise the temperature to 80° C. at 20° C./min (hereinafter referred to as 1stRun). Immediately after reaching 80° C., the temperature is lowered at 100° C./min, again held at −50° C. for 8 minutes, and then raised to 80° C. at 20° C./min (hereinafter referred to as 2ndRun). A DSC curve and its derivative curve are obtained. A baseline from the start to the end of the peak is drawn on the peak of the differential curve of 2ndRun, the peak intensity from the peak top to the baseline is measured, and this is taken as the differential value peak intensity.

Since the composite polymer particles of the present invention have a differential value peak intensity of 2.2×10 ⁻² mW/° C. or less, it is possible to form a coating film excellent in initial water resistance, blocking resistance and transparency. it can. When a plurality of differential value peak intensities are obtained, it is necessary that all the differential value peak intensities be 2.2×10 ⁻² mW/° C. or less. The differential peak intensity is preferably 2.0×10 ⁻² mW/° C. or lower, and more preferably 1.9×10 ⁻² mW/° C. or lower. The lower limit is not particularly limited, but may be 1.0×10 ⁻³ mW/° C.

The composite polymer particles preferably have a mass ratio (A/B) of the fluoropolymer (A) and the acrylic polymer (B) of 10/90 to 75/25. The mass ratio (A/B) is more preferably 40/60 or more, and more preferably 70/30 or less. If the mass ratio (A/B) is too large, the resulting coating film tends to have poor film-forming properties, initial water resistance and blocking resistance, and tends to have high manufacturing costs. If the mass ratio (A/B) is too small, the resulting coating film tends to have poor weather resistance and transparency.

The fluoropolymer (A) contains a repeating unit (fluoroolefin unit) based on fluoroolefin. Examples of the fluoroolefin include tetrafluoroethylene (TFE), hexafluoropropylene (HFP), perfluoro(alkyl vinyl ether) (PAVE),

などのパーフルオロオレフィン；クロロトリフルオロエチレン（ＣＴＦＥ）、フッ化ビニル（ＶＦ）、ビニリデンフルオライド（ＶｄＦ）、トリフルオロエチレン、トリフルオロプロピレン、ヘキサフルオロイソブテン、２，３，３，３−テトラフルオロプロペン、１，３，３，３−テトラフルオロプロペン、１，１，３，３，３−ペンタフルオロプロペンなどの非パーフルオロオレフィンが挙げられる。パーフルオロ（アルキルビニルエーテル）としては、パーフルオロ（メチルビニルエーテル）（ＰＭＶＥ）、パーフルオロ（エチルビニルエーテル）（ＰＥＶＥ）、パーフルオロ（プロピルビニルエーテル）（ＰＰＶＥ）などが挙げられる。

Perfluoroolefins such as; chlorotrifluoroethylene (CTFE), vinyl fluoride (VF), vinylidene fluoride (VdF), trifluoroethylene, trifluoropropylene, hexafluoroisobutene, 2,3,3,3-tetrafluoro Non-perfluoroolefins such as propene, 1,3,3,3-tetrafluoropropene, 1,1,3,3,3-pentafluoropropene and the like. Examples of perfluoro(alkyl vinyl ether) include perfluoro(methyl vinyl ether) (PMVE), perfluoro(ethyl vinyl ether) (PEVE), perfluoro(propyl vinyl ether) (PPVE) and the like.

A functional group-containing fluoroolefin can also be used as the fluoroolefin.
Examples of the functional group-containing fluoroolefin include those represented by the general formula:
CX ³ ₂ =CX ⁴ −(Rf) _m −Y ¹
(In the formula, Y ¹ is —OH, —COOM ² , —SO ₂ F, —SO ₃ M ² (M ² is a hydrogen atom, an NH ₄ group or an alkali metal), a carboxylate, a carboxyester group, an epoxy group or A cyano group; X ³ and X ⁴ are the same or different and each is a hydrogen atom or a fluorine atom; Rf is a divalent fluorine-containing alkylene group or a fluorine-containing oxyalkylene group having 1 to 40 carbon atoms, or 2 to 40 carbon atoms A divalent fluorine-containing alkylene group or a fluorine-containing oxyalkylene group having an ether bond; m is a compound represented by 0 or 1).

Specific examples of the functional group-containing fluoroolefin include, for example,

Etc.

As the fluoroolefin, an iodine-containing monomer, for example, perfluoro(6,6-dihydro-6-iodo-3-oxa-1) described in JP-B-5-63482 and JP-A-62-12734. -Hexene), perfluoro(5-iodo-3-oxa-1-pentene) and other iodides of perfluorovinyl ethers can also be used.

Among them, the fluoroolefin is preferably at least one selected from the group consisting of vinyl fluoride, vinylidene fluoride, tetrafluoroethylene, hexafluoropropylene, and chlorotrifluoroethylene.

The fluoroolefin is more preferably vinylidene fluoride and at least one selected from the group consisting of tetrafluoroethylene, hexafluoropropylene and chlorotrifluoroethylene.

The fluoropolymer (A) may contain, in addition to the above-mentioned fluoroolefin unit, a non-fluorine-based monomer unit copolymerizable with the fluoroolefin. Examples of the non-fluorine-based monomer that can be copolymerized with the fluoroolefin include olefins such as ethylene, propylene and isobutylene, vinyl ether-based monomers, allyl ether-based monomers, vinyl ester-based monomers, and acrylics. Examples of the monomer include methacrylic monomers and methacrylic monomers.

Since the fluoropolymer (A) can form a coating film that is more excellent in initial water resistance, blocking resistance and transparency, it preferably contains a vinylidene fluoride unit as the fluoroolefin unit. From the viewpoint of compatibility with the acrylic polymer (B), it is preferable that the fluoropolymer (A) has a vinylidene fluoride unit content of 50 mol% or more based on all polymer units constituting the fluoropolymer (A). , 70 mol% or more, more preferably 95 mol% or less. The fluoropolymer (A) more preferably contains a vinylidene fluoride unit, and further contains at least one fluoroolefin unit selected from the group consisting of tetrafluoroethylene, hexafluoropropylene and chlorotrifluoroethylene.

The fluoropolymer (A) includes VdF/TFE/CTFE copolymer, VdF/TFE copolymer, VdF/TFE/HFP copolymer, VdF/CTFE copolymer, VdF/HFP copolymer, and PVdF. At least one selected from the group consisting of, VdF/TFE/CTFE=40 to 99/1 to 50/0 to 30 (mol %), VdF/TFE=50 to 99/1 to 50( Mol%), VdF/TFE/HFP=45 to 99/0 to 35/5 to 50 (mol %), VdF/CTFE=40 to 99/1 to 30 (mol %), and VdF/HFP=50 to It is more preferably at least one selected from the group consisting of 99/1 to 50 (mol %).

The acrylic polymer (B) contains a repeating unit based on an acrylic monomer (acrylic monomer unit). The acrylic monomer is preferably at least one selected from the group consisting of acrylic acid, acrylic acid ester, methacrylic acid and methacrylic acid ester.

The acrylic polymer (B) preferably contains at least one type of acrylic monomer unit selected from the group consisting of acrylic acid, acrylic acid ester, methacrylic acid and methacrylic acid ester, and a methacrylic acid ester unit, acrylic acid and methacrylic acid unit. More preferably, it contains at least one acrylic monomer unit selected from the group consisting of an acid and an acrylic ester.

The acrylate ester is preferably an acrylate alkyl ester having an alkyl group having 1 to 10 carbon atoms. Among them, methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, among others, can provide a coating film having more excellent initial water resistance, blocking resistance and transparency. More preferably, it is at least one alkyl acrylate ester selected from the group consisting of cyclohexyl acrylate and glycidyl acrylate, and at least one selected from the group consisting of n-butyl acrylate and 2-ethylhexyl acrylate. More preferably, it is an acrylic acid alkyl ester. The acrylic ester does not contain a hydrolyzable silyl group.

As the methacrylic acid ester, a methacrylic acid alkyl ester having an alkyl group having 1 to 10 carbon atoms is preferable. Among them, methyl methacrylate, n-propyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isopropyl methacrylate, 2-ethylhexyl methacrylate, cyclohexyl methacrylate, among others, from the viewpoint of obtaining a coating film having more excellent initial water resistance, blocking resistance and aesthetics. And at least one methacrylic acid alkyl ester selected from the group consisting of glycidyl methacrylate, and more preferably at least one methacrylic acid alkyl ester selected from the group consisting of methyl methacrylate and cyclohexyl methacrylate. More preferably. The methacrylic acid ester does not contain a hydrolyzable silyl group.

The acrylic polymer (B) is selected from the group consisting of a methacrylic acid ester unit and acrylic acid, methacrylic acid and an acrylic acid ester because a coating film having more excellent initial water resistance, blocking resistance and transparency can be obtained. It is preferable to contain at least one kind of acrylic monomer unit, and a methacrylic acid unit, a methacrylic acid ester unit, an acrylic acid unit, and an acrylic acid can be obtained because a coating film having more excellent initial water resistance, blocking resistance and transparency can be obtained. More preferably, it contains an acid ester unit.

The acrylic polymer (B) is 1 to 10% by mass of methacrylic acid unit, 5 to 90% by mass of methacrylic acid ester unit, and 1 to 10% by mass of acrylic with respect to all the constituent units of the acrylic polymer (B). It is more preferable to contain an acid unit and 5-90 mass% acrylic acid ester unit.

The acrylic polymer (B) may contain a hydrolyzable silyl group-containing monomer unit. As the hydrolyzable silyl group-containing monomer,
CH ₂ =CHSi(OCH ₃ ) ₃ ,
_{CH 2 = CHSi (CH 3)} (OCH 3) 2,
CH ₂ =C(CH ₃ )Si(OCH ₃ ) ₃ ,
_{CH 2 = C (CH 3)} Si (CH 3) (OCH 3) 2,
_{CH 2 = CHSi (OC 2 H} 5) 3,
_{CH 2 = CHSi (OC 3 H} 7) 3,
_{CH 2 = CHSi (OC 4 H} 9) 3,
_{CH 2 = CHSi (OC 6 H} 13) 3,
_{CH 2 = CHSi (OC 8 H} 17) 3,
_{CH 2 = CHSi (OC 10 H} 21) 3,
_{CH 2 = CHSi (OC 12 H} 25) 3,
_{CH 2 = CHCOO (CH 2)} 3 Si (OCH 3) 3,
_{CH 2 = CHCOO (CH 2)} 3 Si (CH 3) (OCH 3) 2,
_{CH 2 = CHCOO (CH 2)} 3 Si (OC 2 H 5) 3,
_{CH 2 = CHCOO (CH 2)} 3 Si (CH 3) (OC 2 H 5) 2,
_{CH 2 = C (CH 3)} COO (CH 2) 3 Si (OCH 3) 3,
_{CH 2 = C (CH 3)} COO (CH 2) 3 Si (CH 3) (OCH 3) 2,
_{CH 2 = C (CH 3)} COO (CH 2) 3 Si (OC 2 H 5) 3,
_{CH 2 = C (CH 3)} COO (CH 2) 3 Si (CH 3) (OC 2 H 5) 2,
_{CH 2 = C (CH 3)} COO (CH 2) 2 O (CH 2) 3 Si (OCH 3) 3,
_{CH 2 = C (CH 3)} COO (CH 2) 2 (CH 2) 3 Si (CH 3) (OCH 3) 2,
_{CH 2 = C (CH 3)} COO (CH 2) 11 Si (OCH 3) 3,
_{CH 2 = C (CH 3)} COO (CH 2) 11 Si (CH 3) (OCH 3) 2,
_{CH 2 = CHCH 2 OCO (o} -C 6 H 4) COO (CH 2) 3 Si (OCH 3) 3,
_{CH 2 = CHCH 2 OCO (o} -C 6 H 4) COO (CH 2) 3 Si (CH 3) (OCH 3) 2,
_{CH 2 = CH (CH 2)} 4 Si (OCH 3) 3,
_{CH 2 = CH (CH 2)} 8 Si (OCH 3) 3,
_{CH 2 = CHO (CH 2)} 3 Si (OCH 3) 3,
_{CH 2 = CHCH 2 O (CH} 2) 3 Si (OCH 3) 3,
_{CH 2 = CHCH 2 OCO (CH} 2) 10 Si (OCH 3) 3
Etc. These hydrolyzable silyl group-containing monomers may be used alone or in combination of two or more.

Among them, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropyltriethoxysilane, and γ-methacryloxypropylmethyl from the viewpoint of good adhesion and storage stability. At least one selected from the group consisting of diethoxysilane is preferable.

The content of the hydrolyzable silyl group-containing monomer unit is preferably 0.1 to 2 mass% with respect to all the constituent units of the acrylic polymer (B). If it is less than 0.1% by mass, the adhesion may be insufficient, or the transparency of the clear coating film may be deteriorated, and if it exceeds 2% by mass, the film forming property and the storage stability may be unstable. There is. A more preferable upper limit is 1.5% by mass. A more preferable lower limit is 0.2% by mass.

The acrylic polymer (B) contains non-fluorinated olefin units such as unsaturated carboxylic acids, hydroxyl group-containing alkyl vinyl ethers, carboxylic acid vinyl esters, α-olefins, aromatic vinyl monomers and epoxy group-containing monomers. It may include one.

Specific examples of unsaturated carboxylic acids include, for example, vinylacetic acid, crotonic acid, cinnamic acid, 3-allyloxypropionic acid, 3-(2-allyloxyethoxycarbonyl)propionic acid, itaconic acid, itaconic acid monoester, maleic acid. , Maleic acid monoester, maleic anhydride, fumaric acid, fumaric acid monoester, vinyl phthalate, vinyl pyromellitic acid, undecylenic acid and the like. Among these, vinyl acetic acid, crotonic acid, itaconic acid, maleic acid, maleic acid monoester, fumaric acid, and fumaric acid monoacid are low in homopolymerity and difficult to form a homopolymer, and easy to control the introduction of a carboxyl group. At least one selected from the group consisting of ester, 3-allyloxypropionic acid, and undecylenic acid is preferable.

Specific examples of the hydroxyl group-containing alkyl vinyl ethers include 2-hydroxyethyl vinyl ether, 3-hydroxypropyl vinyl ether, 2-hydroxypropyl vinyl ether, 2-hydroxy-2-methylpropyl vinyl ether, 4-hydroxybutyl vinyl ether and 4-hydroxy-. 2-methylbutyl vinyl ether, 5-hydroxypentyl vinyl ether, 6-hydroxyhexyl vinyl ether, 2-hydroxyethyl allyl ether, 4-hydroxybutyl allyl ether, glycerol monoallyl ether and the like can be mentioned. At least one selected from the group consisting of 4-hydroxybutyl vinyl ether and 2-hydroxyethyl vinyl ether is preferable in terms of excellent polymerization reactivity.

Specific examples of the carboxylic acid vinyl ester include, for example, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl isobutyrate, vinyl pivalate, vinyl caproate, vinyl versatate, vinyl laurate, vinyl stearate, vinyl cyclohexylcarboxylate. , Vinyl benzoate, vinyl para-t-butyl benzoate and the like. By using the carboxylic acid vinyl ester, the coating film obtained from the aqueous dispersion of the present invention can be provided with properties such as improved gloss and increased glass transition temperature.

Specific examples of α-olefins include ethylene, propylene, n-butene, isobutene and styrene. By using α-olefins, it is possible to impart characteristics such as improved flexibility to the coating film obtained from the aqueous dispersion of the present invention.

Specific examples of the aromatic vinyl monomer include styrenes such as styrene and α-methylstyrene. Specific examples of the epoxy group-containing monomer include allyl glycidyl ether.

An aqueous dispersion comprising the above-mentioned composite polymer particles is also one aspect of the present invention. The above aqueous dispersion further contains water in addition to the composite polymer particles. In addition to water, an organic solvent such as alcohol, glycol ether or ester may be contained.

The aqueous dispersion may include 10 to 60 mass% of composite polymer particles.

In the above aqueous dispersion, if necessary, a film forming aid, an antifreezing agent, a pigment, a filler, a pigment dispersant, an antifoaming agent, a leveling agent, a rheology modifier, an antiseptic, an ultraviolet absorber, an antioxidant, A matting agent, a lubricant, a vulcanizing agent, etc. can also be added.

The above aqueous dispersion can be suitably used as a paint. As a method for coating the above aqueous dispersion, conventionally known methods and conditions can be adopted. For example, there may be mentioned a method in which a base material is applied by a coating method such as spray coating, roll coating, flow coating, roller or brush coating to form a coating film, and then dried at 5 to 200°C. By such a method, a coating film having excellent initial water resistance, blocking resistance and transparency can be formed.

The coating film obtained from the above-mentioned aqueous dispersion is excellent in initial water resistance, blocking resistance and transparency. Further, the coated article including the substrate and the coating film obtained from the above-mentioned aqueous dispersion is excellent in initial water resistance, blocking resistance and transparency. The coated article is preferably obtained by coating the substrate with the aqueous dispersion.

Examples of the base material include metal base materials such as hot dip plated steel plate, stainless steel plate and aluminum steel plate; ceramic base materials such as slate, ceramic siding material, foam concrete and glass; PVC sheet, PET film, polycarbonate, acrylic It can be applied to plastic substrates such as films. Examples of the hot-dip galvanized steel sheet include hot-dip galvanized steel sheet, hot-dip zinc-aluminum-magnesium alloy-plated steel sheet, hot-dip aluminum-zinc-plated steel sheet, hot-dip aluminum-plated steel sheet and the like.

As a method of coating the above-mentioned aqueous dispersion on a substrate, conventionally known methods and conditions can be adopted. For example, a coating method such as spray coating, roll coating, flow coating, roller, or brush coating can be used for the substrate.

The drying method after coating is not particularly limited, and may be natural drying at ambient temperature or low temperature (5 to 60° C.) over a drying time. Even in forced drying at 60° C., especially 60 to 200° C. (base material temperature), a coating film excellent in initial water resistance, blocking resistance and aesthetic appearance can be formed. The time required for forced drying is usually 3 seconds to 10 minutes.

Examples of the above-mentioned paints include weather-resistant paints, especially weather-resistant paints for construction/construction materials, interior/exterior paints for automobiles, interior/exterior paints for electric appliances, paints for office equipment or kitchen appliances, and the like. It has excellent properties and durability and can be advantageously applied to weather-resistant paints for building materials.

The coated article can be used in a wide variety of applications. For example, the interior and exterior of electric appliances (microwave oven, toaster, refrigerator, washing machine, hair dryer, TV, video, amplifier, radio, electric kettle, rice cooker, radio cassette, cassette deck, compact disc player, video camera, etc.) Air conditioner indoor units, outdoor units, air outlets and ducts, air cleaners, heaters and other air conditioner interiors and exteriors, fluorescent lights, chandeliers, reflectors and other lighting equipment, furniture, machine parts, ornaments, combs, Eyeglass frames, natural fibers, synthetic fibers (threads and textiles obtained from them), office equipment (telephones, facsimiles, copiers (including rolls), photographic machines, overhead projectors, physical projectors, clocks, slide projectors. , Desks, bookshelves, lockers, document shelves, chairs, bookends, electronic whiteboards, etc.), automobiles (wheels, door mirrors, malls, door knobs, license plates, handles, instrumental panels, etc.), or kitchen equipment Partitions, bath units, shutters, blinds, curtain rails, accordion curtains, walls, ceilings, floors, etc. for painting various types (range hoods, sinks, cooktops, knives, cutting boards, faucets for water supplies, gas stoves, ventilation fans, etc.) For indoor coating, for exterior use, exterior walls, handrails, gates, shutters and other general house exteriors, building exteriors, ceramic siding materials, foam concrete panels, concrete panels, aluminum curtain walls, steel sheets, galvanized steel sheets, It has a wide range of uses such as stainless steel sheets, PVC sheets, PET films, polycarbonate, acrylic film and other building exterior materials, siding materials, window glass, and others.

A siding material is particularly preferable as a coated article obtained by coating the base material with the aqueous dispersion of the present invention. Examples of siding materials include ceramic siding materials, metal siding materials, and plastic siding materials.
In particular, in the ceramic siding material, in order to improve water resistance, weather resistance and appearance, etc., an acrylic-based, acrylic silicon-based, acrylic urethane-based coating film is often formed on the surface, but the composition of the present invention The coating film obtained from (1) firmly adheres to an acrylic coating film, has excellent hot water resistance, and has excellent transparency. That is, the coated article of the present invention is particularly suitable as a ceramic siding material. The ceramic siding material is, for example, one having a ceramic base material and a coating film obtained by coating the above composition on a ceramic base material, and the ceramic base material has a surface made of an acrylic resin. May be

As the ceramic base material, conventionally known materials can be used. For example, to obtain a wet sheet by papermaking of an aqueous slurry mainly composed of cement, dehydrate press-mold this, dry and cure harden it, and extrude and cast an aqueous kneaded product such as cement. It is possible to use a conventionally known composition such as a cured product of the molded product obtained in the above. The ceramic base material may have an acrylic resin layer on the surface of the molded body.

The composite polymer particles of the present invention can be produced by the production method of the present invention.

The manufacturing method of the present invention is
A step (1) of preparing an aqueous dispersion (1) containing particles comprising a fluoropolymer (A),
Aqueous dispersion (2) containing intermediate particles by adding an acrylic monomer to the aqueous dispersion (1) and polymerizing the acrylic monomer until at least 95% by mass of the added acrylic monomer is consumed. (2) to obtain ), and
Further, a step (3) of adding the acrylic monomer to the aqueous dispersion (2) and polymerizing the acrylic monomer to obtain composite polymer particles dispersed in the aqueous dispersion (3).
It is characterized by including.

The production method of the present invention is not to dissolve fluoropolymer particles in an acrylic monomer, but to prepare an aqueous dispersion of fluoropolymer particles, add the acrylic monomer to the aqueous dispersion, and add an aqueous dispersion containing intermediate particles. It is characterized in that it gains a body. The production method of the present invention is further characterized in that the acrylic monomer is seed-polymerized and then the acrylic monomer is further polymerized, instead of the conventionally known seed polymerization. Due to these characteristics, composite polymer particles having a small differential peak strength can be obtained, and a coating film excellent in initial water resistance, blocking resistance and aesthetics can be formed.

Although it is similar to the production method described in Patent Document 3, the fluorine-containing polymer is dissolved in an ethylenically unsaturated group-containing monomer to prepare a polymer solution, and then an ethylenically unsaturated group-containing unit amount is prepared. When the body is polymerized, it is not possible to obtain composite polymer particles having a small differential peak intensity. Therefore, a coating film having excellent initial water resistance, blocking resistance and transparency cannot be obtained.

The aqueous dispersion (1) containing particles of the fluoropolymer (A) can be prepared by a known method.

The step (2) is performed by adding the acrylic monomer to the aqueous dispersion (1) and polymerizing the acrylic monomer. The above-mentioned polymerization is a seed polymerization in which particles of the fluoropolymer (A) are used as seed particles to emulsion-polymerize an acrylic monomer in water. The aqueous dispersion (1) may contain water, an emulsifier, etc. in addition to the fluoropolymer (A). The solid content concentration of the fluoropolymer (A) in the aqueous dispersion (1) may be 20 to 70% by mass.

In addition to the acrylic monomer, it is preferable to add a polymerization initiator. The acrylic monomer and the polymerization initiator may be added while polymerizing the acrylic monomer.

The total amount of the acrylic monomer added is preferably 20 to 300 parts by mass and more preferably 25 to 230 parts by mass with respect to 100 parts by mass of the particles made of the fluoropolymer (A).

The polymerization initiator used in the step (2) is not particularly limited as long as it can be subjected to a free radical reaction in water, and in some cases, it can be used in combination with a reducing agent. Examples of usable water-soluble polymerization initiators include persulfate and hydrogen peroxide, and examples of the reducing agent include sodium pyrobisulfite, sodium bisulfite, sodium L-ascorbate and Rongalit. Examples of oil-soluble polymerization initiators include diisopropyl peroxydicarbonate (IPP), benzoyl peroxide, dibutyl peroxide, azobisisobutyronitrile (AIBN), and the like. The amount of the polymerization initiator used is preferably 0.05 to 2.0 parts by mass per 100 parts by mass of the acrylic monomer.

In addition to the acrylic monomer, an emulsifier, a chain transfer agent, a chelating agent, a pH adjusting agent, etc. may be added.

The emulsifier used in step (2) may be a reactive emulsifier, a non-reactive emulsifier, or a combination thereof. As the non-reactive emulsifier, conventionally known anionic emulsifiers and nonionic emulsifiers may be used alone or in combination. An amphoteric emulsifier can also be used depending on the case.

Examples of the chain transfer agent used in the step (2) include halogenated hydrocarbons such as chloroform and carbon tetrachloride; mercaptans such as n-dodecyl mercaptan, tert-dodecyl mercaptan and n-octyl mercaptan. it can. The amount of the chain transfer agent used is preferably 0 to 5.0 parts by mass per 100 parts by mass of the acrylic monomer.

In step (2), the polymerization temperature of the acrylic monomer may be 10 to 90° C., and the polymerization time may be 0.5 to 6 hours.

In step (2), the acrylic monomer is polymerized until at least 95 mass% of the added acrylic monomer is consumed. The consumption of the acrylic monomer is preferably 97% by mass or more, more preferably 99% by mass or more.

The consumption of the acrylic monomer is calculated by the following formula by measuring the amount of the unreacted acrylic monomer contained in the aqueous dispersion (2) using gas chromatography.
Consumption amount = {(acrylic monomer addition amount)-(unreacted acrylic monomer amount)}/(acrylic monomer addition amount) x 100

In the production method of the present invention, it is necessary to start the step (3) after polymerizing most of the acrylic monomer added in the step (2). If a large amount of unreacted acrylic monomer remains in the aqueous dispersion (2), the seed polymerization in the step (2) will not be completed, and the step (3) will be started in a state where the seed polymerization is not completed. .. Unless the seed polymerization in the step (2) is completed, composite polymer particles having a small differential peak intensity cannot be obtained.

The acrylic polymer (b-1) formed by the acrylic monomer consumed in the step (2) preferably has a glass transition temperature (Tg) of 40°C or higher. Since the Tg of the acrylic polymer (b-1) is within the above range, the composite polymer particles having a differential peak intensity calculated from a DSC curve of 2.2×10 ⁻² mW/° C. or less can be easily produced. can do. The Tg of the acrylic polymer (b-1) is more preferably 80° C. or higher. The Tg of the acrylic polymer (b-1) may be 150°C or lower.

The Tg of the acrylic polymer (b-1) is calculated from the amount of the monomer constituting the acrylic polymer (b-1) (the consumption of the acrylic monomer in the step (2)) by using the following Fox equation. ..
<Fox formula>
1/Tg=W ₁ /Tg ₁ +W ₂ /Tg ₂ +...+W _n /Tg _n
Tg[K]: Glass transition temperature (K) of acrylic polymer (b-1) composed of n kinds of monomers
Tg _n [K]: glass transition temperature of the homopolymer of each monomer (K)
W _n : Weight fraction of each monomer, W ₁ +W ₂ +... +W _n =1.
As the glass transition temperature of the homopolymer of each monomer, a value obtained by measuring with a suggestive scanning calorimeter can be used.

The step (3) is performed by adding the acrylic monomer to the obtained aqueous dispersion (2) after the step (2) and polymerizing the acrylic monomer. The polymerization is a seed polymerization in which the intermediate particles are used as seed particles and the acrylic monomer is emulsion-polymerized in water. The aqueous dispersion (2) may contain water, an emulsifier, etc. in addition to the above intermediate particles. The solid content concentration of the intermediate particles of the aqueous dispersion (2) may be 20 to 70% by mass.

It is preferable to add a polymerization initiator in addition to the acrylic monomer. The acrylic monomer and the polymerization initiator may be added while polymerizing the acrylic monomer.

The total amount of the acrylic monomer added is preferably 5 to 300 parts by mass, and more preferably 10 to 230 parts by mass, relative to 100 parts by mass of the intermediate particles.

The polymerization initiator used in the step (3) is not particularly limited as long as it can be subjected to a free radical reaction in water, and in some cases, it can be used in combination with a reducing agent. Examples of usable water-soluble polymerization initiators include persulfate and hydrogen peroxide, and examples of the reducing agent include sodium pyrobisulfite, sodium bisulfite, sodium L-ascorbate and Rongalit. Examples of oil-soluble polymerization initiators include diisopropyl peroxydicarbonate (IPP), benzoyl peroxide, dibutyl peroxide, azobisisobutyronitrile (AIBN), and the like. The amount of the polymerization initiator used is preferably 0.05 to 2.0 parts by mass per 100 parts by mass of the acrylic monomer.

In addition to the acrylic monomer, an emulsifier, a chain transfer agent, a chelating agent, a pH adjusting agent, etc. may be added.

The emulsifier used in step (3) may be a reactive emulsifier, a non-reactive emulsifier, or a combination thereof. As the non-reactive emulsifier, conventionally known anionic emulsifiers and nonionic emulsifiers may be used alone or in combination. An amphoteric emulsifier can also be used depending on the case.

Examples of the chain transfer agent used in the step (3) include halogenated hydrocarbons such as chloroform and carbon tetrachloride; mercaptans such as n-dodecyl mercaptan, tert-dodecyl mercaptan and n-octyl mercaptan. it can. The amount of the chain transfer agent used is preferably 0 to 5.0 parts by mass per 100 parts by mass of the acrylic monomer.

In the step (3), the polymerization temperature of the acrylic monomer may be 10 to 90°C, and the polymerization time may be 0.5 to 6 hours.

The acrylic polymer (b-2) formed by the acrylic monomer consumed in the step (3) preferably has a glass transition temperature (Tg) of -10 to 30°C. When the Tg of the acrylic polymer (b-2) is within the above range, a composite polymer particle having a differential value peak intensity calculated from a DSC curve of 2.2×10 ⁻² mW/° C. or less can be easily produced. can do. The Tg of the acrylic polymer (b-2) is more preferably -5 to 10°C.

The Tg of the acrylic polymer (b-2) is calculated according to the method described for the acrylic polymer (b-1).

The Tg of the acrylic polymer (b-1) is higher than the Tg of the acrylic polymer (b-2), and the difference in Tg between the acrylic polymer (b-1) and the acrylic polymer (b-2) is larger than 35°C. Is preferred. This makes it possible to easily produce composite polymer particles having a differential value peak intensity calculated from a DSC curve of 2.2×10 ⁻² mW/° C. or less. The difference in Tg is more preferably 50° C. or higher. The difference in Tg may be 150°C or lower.

The acrylic polymer (b-1) and the acrylic polymer (b-2) constitute the acrylic polymer (B) in the composite polymer particles of the present invention.

In the step (3), composite polymer particles dispersed in the aqueous dispersion (3) can be obtained. The above-mentioned composite polymer particles can be recovered as coagulated particles by adding a coagulant to the aqueous dispersion (3). Further, the aqueous dispersion (3) in which the composite polymer particles are dispersed can be used as it is as a coating material. The above-mentioned pigment and the like may be added to the above aqueous dispersion (3) to prepare a coating material. The obtained composite polymer particles are characterized by the differential peak intensity in the above range.

Next, the present invention will be described with reference to examples, but the present invention is not limited to these examples.

Each numerical value in the examples was measured by the following method.

(1) Initial water resistance test An aluminum plate was prepared by adding 10% of the auxiliary agent diethyldiglycol to the solid content of the obtained aqueous dispersion (100 g of a mixture of acrylic pigment as a precoat and black pigment paste in advance). /M ² and dried at room temperature for 1 day) with a bar coater #30 and dried at 100° C. for 3 minutes to prepare a test coated plate.
After drying, the coated plate within 1 hour was placed in warm water of 60° C., and the warm water was placed in a constant temperature bath of 15° C. After confirming that the warm water was cooled to 15° C., it was taken out from the water and dried in a constant temperature bath at 15° C. for 3 hours. After 3 hours, it was visually confirmed whether the coating film had any abnormality.
The tint was measured with a color difference meter, and those having a ΔL value of 2.0 or less before and after the test were evaluated as ◯, those having 2.1 to 5.0 as Δ, and those having 5.1 or more as x.

(2) Storage elastic modulus (E')
Using a dynamic viscoelastic device DVA220 manufactured by IT-Measurement Control Co., a sample (coating made from the obtained aqueous dispersion) having a length of 35 mm, a width of 5 mm and a thickness of 0.050 mm was measured in a tensile mode, a grip width of 20 mm, and measured. Temperature Measured from room temperature to 100° C., temperature rising rate of 2° C./min, and frequency of 10 Hz. From the measurement result, the storage elastic modulus at 40° C. was described.

(3) Blocking resistance The aqueous dispersion obtained was supplemented with 10% of the auxiliary diethyldiglycol based on the solid content, coated on a aluminum plate with a 6-mil applicator, and dried by heating at 100°C for 3 minutes. Immediately after drying, the foamed polyurethane was placed thereon, a load of 2.5 kg/cm ² was applied, and the mixture was stored at 40°C. After 16 hours, if the traces of the polyurethane could not be visually confirmed on the coating film, it was evaluated as O, if it was slightly attached, it was evaluated as Δ, and if it was clearly attached, it was evaluated as X.

(4) Transparency An aluminum plate was prepared by adding 10% of the diethyldiglycol auxiliary agent to the solid content of the obtained aqueous dispersion (100 g/m of a mixture of an acrylic-based paint and a black pigment paste as an undercoat in advance). ² ) and dried at room temperature for 1 day) with a bar coater #30 and dried at 100° C. for 3 minutes to prepare a test coated plate.
The transparency of the obtained coating film was visually confirmed. When the coating film had no turbidity, it was evaluated as ◯, when the coating film had a slight turbidity, as Δ, and when the entire coating film was clouded as x.

(5) Differential value Peak intensity It was measured using a differential scanning calorimeter (manufactured by METTLER TOLEDO, DSC822e, calculation software: STARe). The measurement method was as follows: 10 mg of the sample was held at -50°C for 8 minutes while purging with nitrogen at 40 to 50 ml/min, and then heated to 80°C at 20°C/min (hereinafter referred to as 1st Run). Immediately after reaching 80°C, the temperature was lowered at 100°C/min, the temperature was again held at -50°C for 8 minutes, and then the temperature was raised to 80°C at 20°C/min (hereinafter referred to as 2nd Run). The DSC curve and its derivative curve were obtained. A baseline from the start to the end of the peak was drawn on the peak of the differential curve of 2nd Run, the peak intensity from the peak top to the baseline was measured, and this was taken as the differential value peak intensity.

Example 1
A 2-liter glass four-neck separable flask equipped with a stirrer, a reflux tube, a thermometer, and a dropping funnel was placed in a VdF/TFE/CTFE copolymer (VdF/TFE/CTFE) copolymer as an aqueous dispersion of seed particles of a fluoropolymer. /TFE/CTFE=72.1/14.9/13 (mol %)) in an aqueous dispersion (solid concentration 46.6 mass %) of 820.82 parts by mass of polyoxyalkylene polycyclic phenyl ether. 7.65 parts by mass of the sulfate ammonium salt and 178 parts by mass of ion-exchanged water were added and mixed sufficiently to prepare an aqueous dispersion.
Next, at room temperature with stirring, a mixed monomer of 252.45 parts by mass of methyl methacrylate (MMA), 2.54 parts by mass of methacrylic acid (MAA), and 2.55 parts by mass of γ-methacryloxypropyltriethoxysilane was added dropwise. After the temperature was raised to 75° C., ammonium persulfate (APS) was added in a predetermined amount to proceed polymerization. After that, sampling is performed, and it is confirmed by gas chromatography that each monomer is within 1%, and the next polymerization is performed. With stirring at 75°C,
Methyl methacrylate (MMA) 58.40 parts by mass, cyclohexyl methacrylate (CHMA) 12.75 parts by mass, acrylic acid (AA) 3.83 parts by mass, 2-hydroxyethyl methacrylate (HEMA) 6.38 parts by mass, 2-ethylhexyl. Polymerization was proceeded by adding 46.16 parts by mass of a mixed monomer of acrylate (2-EHA) and a predetermined amount of ammonium persulfate (APS). After the polymerization, sampling was performed, and it was confirmed by gas chromatography that each monomer was within 1%. After aging, the reaction solution was cooled to room temperature to terminate the reaction and neutralized with a pH adjuster to obtain an aqueous dispersion of polymer particles.

Using the obtained aqueous dispersion, various tests and measurements were performed by the methods described above. The results are shown in Table 1.

Examples 2-8 and Comparative Examples 1-7
An aqueous solution of polymer particles was prepared in the same manner as in Example 1 except that the types and amounts of the VdF-based polymer and the acrylic monomer used in the first, second and third stages were changed as shown in Tables 1 and 2. A dispersion was obtained and various tests and measurements were performed. In Comparative Examples 5 and 6, a mixture of the polymer particles described in the "second step" and the polymer particles described in the "third step" in the table at a predetermined ratio was used. The results are shown in Tables 1 and 2.

The abbreviations in Tables 1 and 2 are as follows.
VTC: VdF/TFE/CTFE copolymer (VdF/TFE/CTFE=72.1/14.9/13 (mol %))
VTH: VdF/TFE/HFP copolymer (VdF/TFE/HFP=77/17/6 (mol %))
VH:VdF/HFP copolymer (VdF/HFP=78/22 (mol %))
MMA: methyl methacrylate n-BA: n-butyl acrylate CHMA: cyclohexyl methacrylate MAA: methacrylic acid AA: acrylic acid GMA: glycidyl methacrylate n-BMA: n-butyl methacrylate 2-EHA: 2-ethylhexyl acrylate 2-HEMA: 2- Hydroxyethyl methacrylate

Claims (10)

The fluoropolymer (A) and the acrylic polymer (B) are contained in the same particle, and the differential value peak intensity calculated from the differential scanning calorimetry curve obtained by the differential scanning calorimetry is 2.2×10 ⁻² mW/° C. or less, the weight ratio of the fluoropolymer (a) and the acrylic polymer (B) (a / B) is Ri 40 / 60-75 / 25 der acrylic polymer (B), .gamma.-methacryloxypropyl trimethoxysilane A hydrolyzable silyl group-containing unit based on at least one selected from the group consisting of silane, γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropyltriethoxysilane, and γ-methacryloxypropylmethyldiethoxysilane. Composite polymer particles containing 0.1 to 2 mass% of a monomer unit with respect to all constituent units of the acrylic polymer (B) . The composite polymer particle according to claim 1, wherein the fluoropolymer (A) contains a vinylidene fluoride unit. The fluoropolymer (A) contains a vinylidene fluoride unit and at least one fluoroolefin unit selected from the group consisting of tetrafluoroethylene, hexafluoropropylene and chlorotrifluoroethylene. Coalesced particles. The composite polymer particle according to claim 1, 2 or 3, wherein the acrylic polymer (B) contains at least one acrylic monomer unit selected from the group consisting of acrylic acid, acrylic acid ester, methacrylic acid and methacrylic acid ester. The acrylic polymer (B) contains a methacrylic acid ester unit and at least one acrylic monomer unit selected from the group consisting of acrylic acid, methacrylic acid, and an acrylic acid ester. Composite polymer particles. An aqueous dispersion comprising the composite polymer particles according to claim 1, 2, 3, 4 or 5. The aqueous dispersion according to claim 6, which is a paint. A coating film obtained from the aqueous dispersion according to claim 6. A coated article comprising a substrate and a coating film obtained from the aqueous dispersion according to claim 6. A step (1) of preparing an aqueous dispersion (1) containing particles comprising a fluoropolymer (A),
An aqueous dispersion (2) containing intermediate particles by adding an acrylic monomer to the aqueous dispersion (1) and polymerizing the acrylic monomer until at least 95% by mass of the added acrylic monomer is consumed. (2) to obtain ), and
Furthermore, a step (3) of obtaining the composite polymer particles dispersed in the aqueous dispersion (3) by adding the acrylic monomer to the aqueous dispersion (2) and polymerizing the acrylic monomer.
Including,
The acrylic polymer (b-1) formed by the acrylic monomer consumed in the step (2) has a glass transition temperature (Tg) of 40° C. or higher,
The acrylic polymer (b-2) formed by the acrylic monomer consumed in the step (3) has a glass transition temperature (Tg) of -10 to 30°C,
The Tg of the acrylic polymer (b-1) is higher than the Tg of the acrylic polymer (b-2), and the difference in Tg between the acrylic polymer (b-1) and the acrylic polymer (b-2) is larger than 35° C.,
The mass ratio of the fluoropolymer constituting the composite polymer particles (A) and the acrylic polymer (B) (A / B) Ri is 40 / 60-75 / 25 der,
The acrylic polymer (B) is selected from the group consisting of γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropyltriethoxysilane, and γ-methacryloxypropylmethyldiethoxysilane. 0.1 to 2% by mass of the hydrolyzable silyl group-containing monomer unit based on at least one of the above-mentioned, based on the total constitutional units of the acrylic polymer (B). Method for producing coalesced particles.

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