JP2002188052A - Composition for aqueous coating material of fluorine- based copolymer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composition for an aqueous coating material of a fluorine-based copolymer excellent in stability and film-forming capability as a dispersion, and also improving blocking resistance, solvent resistance, weather resistance, waterproofness, soil resistance, transparency and close adhesion of its coating film. SOLUTION: This composition for the aqueous coating material is obtained by dispersing a fluorine-based copolymer consisting of (a) polymerizing unit based on a fluoroolefin, (b) a polymerizing unit based on propylene, (c) a polymerizing unit based on ethylene and/or (d) a polymerizing unit based on butylenes and (e) a polymerizing unit based on a vinyl monomer having hydroxy group, and having a specific melting point and a polyisocyanate compound in water.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluorine-containing copolymer composition for aqueous coating.

[0002]

2. Description of the Related Art Conventionally, vinylidene fluoride resins have been widely used as baking type paints because they have good weather resistance, heat resistance and chemical resistance and are soluble in solvents at high temperatures. As this vinylidene fluoride resin, a vinylidene fluoride homopolymer or a copolymer of vinylidene fluoride and a fluoroolefin (tetrafluoroethylene, hexafluoropropylene, chlorotrifluoroethylene, etc.) has been proposed.

[0003] Copolymers of fluoroolefins with cyclohexyl vinyl ether and various other monomers are soluble in organic solvents at room temperature, and when used as coatings, have a high transparency and high gloss. It is known that a coating film having excellent properties such as weather resistance, water / oil repellency, stain resistance, and non-adhesion is provided (for example, see JP-A-55-4).
See No. 4083. ), And its use is increasing in the field of weather-resistant paints for interiors and exteriors of buildings and the like.

On the other hand, in recent years, from the viewpoint of environmental protection such as air pollution, the use of organic solvents has been increasingly regulated, and there has been an increasing social demand for aqueous paints and powder paints that do not use organic solvents.

[0005] From this viewpoint, fluororesins are also
A study has been made on aqueous dispersion, and in the case of vinylidene fluoride-based resin, a method of emulsion-polymerizing an acrylic monomer in the presence of vinylidene fluoride-based resin particles (see, for example,
See JP-A-8884, JP-A-4-325509 and the like. ) Has been proposed.

Aqueous dispersion of a copolymer of a fluoroolefin with cyclohexyl vinyl ether and other various monomers has been studied, and it has been reported that the copolymer can be produced by emulsion polymerization (for example, Japanese Patent Application Laid-Open No. 5
See JP-A-7-34107, JP-A-61-231044 and the like. ). Further, there has been proposed an aqueous dispersion in which a fluorinated copolymer containing a polymerized unit based on a macromonomer having a hydrophilic portion as an essential component is dispersed in water (for example, see JP-A-2-225550). ).
It has been reported that this aqueous dispersion has excellent film-forming properties and good mechanical strength of a coating film, and can be produced without using an emulsifier or a hydrophilic organic solvent.

However, the stability of the aqueous dispersion of the vinylidene fluoride resin is not always good, and the transparency of the coating film is poor due to the crystallinity of the resin. When the crystallinity is lowered for improvement, there is a problem that the glass transition temperature of the coating film is too low and the stain resistance is deteriorated. These problems are alleviated by seed polymerization of acrylic monomers, but are not sufficient. There was also a problem in film forming properties. Further, the cost of the vinylidene fluoride-based resin increases because it is composed of only a fluoroolefin. Copolymers of fluoroolefins with cyclohexyl vinyl ether and other various monomers have good transparency and film forming properties and are sufficiently practical, but the monomers are relatively expensive. Further improvement was desired.

The present inventors have found that a composite aqueous dispersion of a fluoroolefin, a copolymer of ethylene, propylene or the like, and a (meth) acrylate copolymer solves the above problems. However, when an article is coated in a factory and the coating is heated and dried, if the coating film hardness is insufficient, the coated articles after drying are stacked on each other (see, for example, JP-A-2000-128934). As a result, it has been found that a decrease in gloss, scratches and the like of the coating film occur, which causes the appearance unevenness. Further, in order to stack the coated articles efficiently, it is necessary to improve the coating efficiency, shorten the cooling time after heating and drying, and increase the number of stacked articles. Therefore, in order to increase the efficiency of commercialization of a coated article in a coating factory, it is necessary to increase the blocking resistance of the coating film so that no problem occurs in the stacking process.

[0009]

SUMMARY OF THE INVENTION The present invention is intended to solve the above-mentioned problems of the prior art, and is excellent in blocking resistance, water resistance, weather resistance and stain resistance of a coating film. An object of the present invention is to provide an excellent fluorine-based copolymer water-based coating composition.

[0010]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and according to the present invention, the following inventions are provided.

(1) (a) a polymerized unit based on a fluoroolefin, (b) a polymerized unit based on propylene,
A copolymer comprising (c) a polymerization unit based on ethylene and / or (d) a polymerization unit based on butylene, and (e) a polymerization unit based on a vinyl monomer having a hydroxyl group and a molecular weight of less than 250. A fluorine-based copolymer (A1) having a melting point in the range of 40 to 150 ° C. and a self-emulsifying polyisocyanate compound (B) dispersed in water. Composition.

(2) (a) a polymerized unit based on a fluoroolefin, (b) a polymerized unit based on propylene,
(C) a polymerization unit based on ethylene and / or (d) a polymerization unit based on butylene, (e) a polymerization unit based on a vinyl monomer having a hydroxyl group and a molecular weight of less than 250, and (f) a vinyl ester or a vinyl ether A polymer unit based on at least one selected from the group consisting of isopropenyl ether and allyl ether and / or (g) a polymer unit based on a macromonomer having a hydrophilic group and a molecular weight of 250 or more. And its melting point is 40
A fluorine-based copolymer (A2) in the range of ~ 150 ° C,
And a self-emulsifying polyisocyanate compound (B) dispersed in water.

(3) (a) a polymerized unit based on a fluoroolefin, (b) a polymerized unit based on propylene,
A fluorine-based copolymer (X1) containing (c) a polymerization unit based on ethylene and / or (d) a polymerization unit based on butylene;
(H) In the presence of 100 parts by mass of the particles of (A), (h) a (meth) acrylic acid alkyl ester having an alkyl group having 1 to 18 carbon atoms and (i) a hydroxyl group, and having a molecular weight of less than 250 (meth) A composite particle (A3) obtained by emulsion polymerization of 5 to 100 parts by mass of a radical polymerizable monomer mixture (Y1A) containing an acrylate ester, and a self-emulsifying polyisocyanate compound (B) A composition for an aqueous paint, which is dispersed in water.

(4) (a) polymerized units based on fluoroolefin, (b) polymerized units based on propylene,
Fluorine containing (c) a polymerization unit based on ethylene and / or (d) a polymerization unit based on butylene, and (j) a polymerization unit based on a vinyl monomer having a reactive group that does not react with a hydroxyl group of the following (i). Of the particles of the copolymer (X2A)
(H) an alkyl group having 1 carbon atom in the presence of 00 parts by mass;
To (18) alkyl (meth) acrylates, (i)
(Meth) acrylic acid esters having a hydroxyl group and a molecular weight of less than 250, and (l) having a reactive group other than a hydroxyl group capable of reacting with the reactive group of the above (j) to form a bond, Composite particles (A4) obtained by emulsion polymerization of 5 to 100 parts by mass of a radically polymerizable monomer mixture (Y2A) containing (meth) acrylic acid and / or (meth) acrylic acid ester; An aqueous coating composition, wherein the emulsifiable polyisocyanate compound (B) is dispersed in water.

(5) The monomer mixture (Y2A) is
The aqueous coating composition according to the above (4), further comprising (k) a (meth) acrylic acid ester having a hydrophilic group and a molecular weight of 250 or more (excluding the above (1)).

(6) The aqueous coating composition according to any one of (1) to (5), wherein the solid content in the composition is 10%.
An aqueous coating composition in which 0.1 to 100 parts by mass of a solid content of an inorganic silicon compound and / or an organic silicon compound is blended with respect to 0 parts by mass.

(7) At least one selected from the group consisting of an ultraviolet absorber, a film-forming aid and a thickener is blended with the aqueous coating composition according to any one of the above (1) to (6). Aqueous paint compositions.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, preferred embodiments of the present invention will be described in detail. In the present invention, basically,
(A) a polymerized unit based on a fluoroolefin, (b) a polymerized unit based on propylene, (c) a polymerized unit based on ethylene and / or (d) a polymerized unit based on butylene, and (e) a hydroxyl group. An aqueous dispersion of a fluorinated copolymer (A1) containing a polymerized unit based on less than 250 vinyl monomers (hereinafter sometimes abbreviated as a hydroxyl group-containing vinyl monomer) is used.

Here, the fluorine-based copolymer (A1) is preferably constituted by a composition ratio of polymerized units based on the following monomers (hereinafter, sometimes referred to by the names of the monomers). That is, (a) 20 to 70 mol% of a fluoroolefin, (b) 10 to 60 mol% of propylene, (c) ethylene (2) to (40) mol%, (d) butylene (2) to (40) mol% (E) 1-30 mol% of a vinyl monomer having a hydroxyl group.

The composition ratio is more preferably (a) 25 to 65 mol% of a fluoroolefin, (b) 12 to 55 mol% of propylene, (c) ethylene (3) to (35) mol%, and (d) butylene. (3) to (35) mol%, (e) 2 to 25 mol% of a vinyl monomer having a hydroxyl group,

Most preferably, (a) 30 to 60 mol% of fluoroolefin, (b) 14 to 50 mol% of propylene, (c) ethylene (4) to (30) mol%, (d) butylene (4) to (30) mol%, (e) 3-20 mol% of a vinyl monomer having a hydroxyl group.

Here, the composition ratio of the polymerization units (c) ethylene and (d) butylene is shown in parentheses (40),
The notations (35), (30) and the like have the following meanings. That is, as specified in the claims, at least one of (c) and (d) is always included, and the other may not be included at all.
(35), (30) and the like indicate the content of the contained component (c) or (d) alone in that case. In addition,
When both (c) and (d) are contained, (4)
0), (35), (30) and the like indicate the total content of both components.

If the proportion of the polymerized unit (a) based on the fluoroolefin in the present invention is too small, the weather resistance will be poor, and if it is too large, the cost will be higher than the improvement in weather resistance. Not preferred. The above range is selected in consideration of these.

In addition, polymerized units (b) based on propylene
If the proportion is too small, the melting point will be too high, and the flexibility of the coating film will be insufficient. If it is too large, the fluorocopolymer will be rubbery and the hardness of the coating film will be insufficient. Thus, the above range is selected.

As described above, the polymerized unit (c) based on ethylene and the polymerized unit (d) based on butylene may be used together, or only one of them may be used. At least one must be used. (C)
If the ratio of (d) is too large, the melting point is too high, and the crystallization of the coating film is large, and the transparency is reduced. Conversely, if the amount is too small, the fluorocopolymer becomes rubbery and the hardness is insufficient. The above range is selected as preferable in consideration of these.

When the proportion of the polymerized unit (e) based on a vinyl monomer having a hydroxyl group and a molecular weight of less than 250 is too large,
When the aqueous dispersion is polymerized, the stability at the time of polymerization is lowered. When the amount is too small, the crosslinking density of the coating film is lowered and the blocking resistance is insufficient. The above range is selected as preferable in consideration of these.

In the present invention, the fluoroolefin (a) includes trifluoroethylene, chlorotrifluoroethylene, tetrafluoroethylene, vinylidene fluoride, trifluoropropylene, tetrafluoropropylene, pentafluoropropylene, hexafluoropropylene, tetrafluoropropylene, A fluoroolefin having about 2 to 4 carbon atoms containing a fluorine atom, such as fluorobutylene and pentafluorobutylene, is preferred, and a perfluoroolefin is particularly preferred. Most preferably, it is tetrafluoroethylene. Note that other halogen atoms such as a chlorine atom may be contained together with the fluorine atom.

In the present invention, 1-butylene, 2-butylene and isobutylene can be used as the butylene of (d). Isobutylene is most preferred in terms of availability. Further, a mixture thereof may be used.

In the present invention, (e) having a hydroxyl group,
Examples of the vinyl monomer having a molecular weight of less than 250 include 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, 1-hydroxymethyl-4-vinyloxymethylcyclohexane, 2-hydroxyethyl crotonate, 2-hydroxyethylallyl ether, Allyl alcohol, 2-hydroxyethyl (meth) acrylate,
3-hydroxypropyl (meth) acrylate, (meth)
Examples thereof include 2-hydroxypropyl acrylate and 4-hydroxybutyl (meth) acrylate. The hydroxyl group-containing vinyl monomer (e) has a molecular weight of less than 250. If the molecular weight of (e) is 250 or more, the hardness of a crosslinked coating film formed by reacting with the self-emulsifying polyisocyanate compound (B) is undesirably reduced.

The melting point of the fluorine-based copolymer (A1 or A2) in the present invention is from 40 to 150 ° C., preferably from 60 to 120 ° C. The range of the melting point of the fluorine-based copolymer (X1A or X2A) described later is 40 to 1
50 ° C is preferable, and particularly preferably 60 to 120 ° C. If the melting point is too low, the hardness of the coating film will be insufficient. If the melting point is too high, sufficient fluidity will not be obtained at the time of heating and coating will impair the appearance of the coating film.

In the present invention, the fluorine-based copolymer (hereinafter referred to as "the copolymer")
Unless otherwise specified, A1, A2, X1A and X2A are included. The range of the glass transition temperature is -20 ° C to 80 ° C.
And more preferably 0 to 70 ° C. If the glass transition temperature is too low, the hardness of the coating film is insufficient, and if it is too high, sufficient fluidity cannot be obtained at the time of heating coating, and the appearance of the coating film is impaired.

The melting point was measured by a scanning differential calorimeter (DS).
The exothermic peak when the sample was heated at 10 ° C./min was determined by C), and the temperature at that time was determined as the melting point. In the case where the distribution of the melting point peaks was wide, the lowest point of the downwardly convex portion was defined as the melting point. The glass transition temperature was defined as the point where two tangents intersect at a portion where a rapid change in the temperature gradient occurs in the DSC temperature rise curve.

The Q value as an index of the molecular weight of the fluorocopolymer in the present invention is preferably in the range of 0.1 to 10,000. More preferably 1 to 1000,
More preferably, it is 10 to 500.

When the Q value is less than 0.1, the fluidity of the particles tends to decrease, and the film forming property and the smoothness of the coating film tend to decrease. If it exceeds 10,000, the mechanical strength of the coating film is impaired.

Note that the Q value is determined using a high-level flow tester.
Filling a cylinder with an inner diameter of 11.3mm with a nitrogen-based copolymer
And a diameter of 2.1 mm under a load of 140 ° C. and 68.6 N,
Extruded from 8.0mm long nozzle, unit time at that time
Volume extruded between (mm ^Three/ Sec)
Value.

The range of the particle size of the fluorine-based copolymer in the present invention is preferably from 50 nm to 300 nm, more preferably from 70 to 200 nm.

The particle size is an average particle size measured using a laser light scattering particle size measuring device (ELS-3000, manufactured by Otsuka Electronics Co., Ltd.).

If the particle size is less than 50 nm, the mechanical stability tends to decrease, and the film forming property tends to decrease. 30
If it is larger than 0 nm, sedimentation stability, thermal stability,
Impairs mechanical and chemical stability. However, if it is less than 10% by mass, particles having a particle diameter outside the range may be present.

The content of fluorine atoms in the fluorocopolymer of the present invention is preferably in the range of 20 to 65% by mass, more preferably 30 to 60% by mass. If the content of the fluorine atom is too small, the weather resistance will be reduced, and if it is too large, the adhesion of the coating film to the substrate will be reduced.

The fluorine-based copolymer of the present invention comprises (f) a vinyl ester, vinyl ether, isopropenyl ether and allyl ether in addition to the polymerized units based on the monomers (a) to (e). It may be a copolymer (A2) containing a polymerized unit based on at least one monomer selected from the group.

When (f) a polymerized unit based on a monomer such as a vinyl ester is contained, not only the pigment dispersibility and the adhesion to the substrate are improved, but also the affinity for the acrylic monomer is improved. It has the characteristic that the transparency and weather resistance of the coating film are improved by improving the properties.

If the amount of the polymerized units based on the monomer (f) such as vinyl ester, vinyl ether, isopropenyl ether or allyl ether is too large, the coating film becomes tacky. The effect of improving dispersibility, adhesion to a substrate, affinity with an acrylic monomer, and the like is not sufficiently exhibited.

Therefore, the content of the polymerized unit based on the component (f) such as vinyl ester is preferably about 5 to 20 mol%.

Examples of the vinyl ester include vinyl acetate, vinyl propionate, vinyl butyrate, vinyl pivalate, vinyl caproate, vinyl caprylate, and vinyl stearate. Examples of the vinyl ether include methyl vinyl ether, ethyl vinyl ether, isopropyl vinyl ether, n-butyl vinyl ether, and cyclohexyl vinyl ether.
Examples of the isopropenyl ether include methyl isopropenyl ether, ethyl isopropenyl ether, isopropyl isopropenyl ether, n-butyl isopropenyl ether, and cyclohexyl isopropenyl ether. Examples of the allyl ether include ethyl allyl ether, isopropyl allyl ether, n-butyl allyl ether, isobutyl allyl ether, and the like.

In the fluorine-based copolymer of the present invention, in addition to the polymerization units based on the monomers (a) to (e) or (a) to (f), (g) a hydrophilic group Has,
It may be a copolymer (A2) containing a polymerized unit based on a macromonomer having a molecular weight of 250 or more (hereinafter sometimes abbreviated as a hydrophilic macromonomer).

When the polymer units (g) based on the hydrophilic macromonomer are contained, not only the mechanical stability and chemical stability of the aqueous dispersion of the present invention are improved, but also the film forming property and coating property are improved. The film is excellent in mechanical strength, and has the feature that water resistance and stain resistance are improved because an emulsifier for stabilization is not required or used at all.

The macromonomer is a low molecular weight polymer or oligomer having a radically polymerizable unsaturated group in the molecule or at one end. That is, it is a compound having a radical polymerizable unsaturated group in the molecule or at one end and having at least four repeating units such as the following polyoxyethylene groups in order to obtain sufficient water dispersion stability. A compound having a radically polymerizable unsaturated group at one terminal is preferred because of its high polymerization reactivity. Depending on the type of repeating unit,
Usually, those having 50 or less repeating units are preferably employed from the viewpoint of polymerizability, water resistance and the like.

The molecular weight of the hydrophilic macromonomer (g) is 250 or more. When the molecular weight is less than 250, the effect of stably dispersing the particles in water becomes insufficient.

Here, the radical polymerizable unsaturated group includes a vinyl group (CH ₂ ＣＨCH—) and an allyl group (CH ₂ ＣC
HCH ₂ —), propenyl group (CH ₃ CH ＝ CH—), isopropenyl group (CH ₂ ＣC (CH ₃ ) —), acryloyl group (CH ₂ ＣＨCHCO—), methacryloyl group (CH ₂
ＣC (CH ₃ ) CO—), an alkenyl group (—CH ＝ CH)
−) And the like. In particular, one having a vinyl ether type or allyl ether type at one end is preferable.

As the hydrophilic group, a nonionic hydrophilic group is desirable. A nonionic hydrophilic group such as a polyoxyethylene group or a polyoxypropylene / polyoxyethylene group is particularly preferable from the viewpoint of the influence on the strength of the hydrophilic property and the physical properties of the coating film.

For example, (1) CH ₂ = CHOCH ₂ -cyclo-C ₆ H ₁₀ -CH ₂ O (CH ₂ CH ₂ O) _t X (where t is an integer of 4 to 40, X is a hydrogen atom, It represents a lower alkyl group or a lower acyl group.)

(2) CH ₂ = CHO-RO- (CH ₂ CH ₂ O) _t X (where t and X have the same meanings as described above. R is a divalent carbon having 2 to 15 carbon atoms) Represents a hydrogen group.)

(3) CH ₂ = CHO-RO- (CH ₂ CH (CH ₃ ) O) _u -CH ₂ O
_{(CH 2 CH 2 O) t} X ( where, u is an integer of from 1 to 10, R, t, X have the same meanings as defined above.)

(4) CH_Two= CHCH_TwoO-R-O- (CH_TwoCH (CH_Three) O)_u-CH
_TwoO (CH_TwoCH_TwoO)_tX (where R, u, t, and X have the same meanings as above)
You. ) Are exemplified. (-Cyclo-C₆H_Ten- )
There are 1,4-, 1,3-, 1,2-
Usually, 1,4- is adopted.

Among them, (g) having a vinyl ether type structure at one end is preferred because it has excellent alternating copolymerizability with fluoroolefin and good weather resistance of the copolymer coating film. For example, the following are exemplified. _{(5) CH 2 = CHOCH 2} -cyclo-C 6 H 10 -CH 2 O- (CH 2 CH 2 O) n H (6) CH 2 = CHO-C 4 H 8 -O- (CH 2 CH 2 O ) _n H (7) CH ₂ = CHO-C ₄ H ₈ -O- (CH ₂ CH (CH ₃ ) O) _m -CH ₂ O (CH ₂ CH ₂ O) _n
H In the above formulas (5), (6) and (7), m is 1 to 1
Integer of 0 and n show the integer of 4-40.

These hydrophilic macromonomers can be prepared by polymerizing formaldehyde with an alkyl vinyl ether or alkyl allyl ether having a hydroxyl group,
Alternatively, it can be produced by a method such as ring-opening polymerization of a compound having an alkylene oxide or a lactone ring. It can also be produced by introducing a vinyl ether group, an allyl ether group or the like into the terminal of a hydrophilic polymer such as polyethylene glycol.

The fluorinated copolymer (A2) in the present invention
It is desirable that the polymer units (g) based on the hydrophilic macromonomer are contained in a proportion of 0.1 to 25 mol%, preferably 0.3 to 20 mol%. When the content of the polymerized unit based on the hydrophilic macromonomer is too small, the mechanical stability and the chemical stability of the aqueous dispersion cannot be remarkably improved. However, it is not preferable because the water resistance decreases.

In the present invention, by incorporating (j) a vinyl monomer having a reactive group into a fluorine-based copolymer as a base, a complexing treatment as described later is carried out to make the coating film transparent. It can also improve the performance.

The vinyl monomer having a reactive group (j) has at least one functional group selected from the group consisting of a hydroxyl group, a carboxyl group, an epoxy group, a hydrolyzable silyl group and an amino group. Preferably, there is. However, the reactive group in (j) is the following (i)
Does not react with the hydroxyl group of

As the vinyl monomer having a hydroxyl group as the above (j), the monomers exemplified in the above (e) can be used. Examples of the vinyl monomer having a carboxyl group as (j) include acrylic acid, methacrylic acid, crotonic acid, isocrotonic acid, 10-undecenoic acid, 9-octadecenoic acid (oleic acid), fumaric acid, and maleic acid. Examples thereof include monomers having a carboxyl group, such as unsaturated fatty acids, and carboxylic acid group-containing monomers represented by the following formulas (8) and (9).

(8) CH ₂ ＣＨCHOR ¹ OCOR ² COOM (9) CH ₂ ＣＨCHCH ₂ OR ³ OCOR ⁴ COOM (wherein R ¹ and R ³ are divalent hydrocarbon groups having 2 to 15 carbon atoms) , R ² and R ⁴ are a saturated or unsaturated linear or cyclic divalent hydrocarbon group, and M is a hydrogen atom, a hydrocarbon group, an alkali metal or a nitrogen atom-containing group.)

Examples of the vinyl monomer having an epoxy group as (j) include epoxy group-containing alkyl vinyl ethers such as glycidyl vinyl ether; epoxy group-containing alkyl allyl ethers such as glycidyl allyl ether; glycidyl acrylate and glycidyl. Examples include an epoxy group-containing alkyl acrylate such as methacrylate or methacrylate.

Examples of the vinyl monomer having a hydrolyzable silyl group as (j) include trimethoxyvinylsilane, triethoxyvinylsilane, γ- (meth) acryloyloxypropyltrimethoxysilane, γ- (meth)
Acryloyloxypropyltriethoxysilane, γ-
Examples include hydrolyzable silyl group-containing esters such as (meth) acryloyloxypropylmethyldimethoxysilane and γ- (meth) acryloyloxypropyltriisopropenyloxysilane. The polymerizable unit containing a hydrolyzable silyl group can be introduced by copolymerizing these monomers containing a hydrolyzable silyl group.

Examples of the vinyl monomer having an amino group as (j) include diethylaminoethyl (meth) acrylate and dimethylaminoethyl (meth) acrylate.

The proportion of the vinyl monomer having a reactive group (j) is 0.1 to 30 mol%. If the content is too large, it becomes unstable at the time of polymerization. If the content is too small, the effect of transparency by the compounding treatment is small.

The fluorinated copolymer in the present invention is one dispersed in water. Here, the water-based paint composition of the present invention basically has excellent dispersion stability without using an emulsifier usually used in a fluorine-based copolymer water-based paint composition, but excludes the use of an emulsifier. It does not do.

As the emulsifier, a commonly used nonionic emulsifier or anionic emulsifier can be used alone or in combination.

The above-mentioned emulsifier is usually added and used at the time of polymerization, but the same kind of emulsifier and / or different kinds of emulsifier may be added to the aqueous dispersion after polymerization.

The initiation of emulsion polymerization in the present invention is carried out by the addition of a polymerization initiator in the same manner as in the usual initiation of emulsion polymerization. As the polymerization initiator, a usual radical initiator can be used, and particularly, a water-soluble initiator is preferably employed, and specifically, a persulfate such as ammonium persulfate, hydrogen peroxide or hydrogen peroxide or hydrogen peroxide is used. Sodium, a redox initiator composed of a combination with a reducing agent such as sodium thiosulfate, an inorganic initiator in which a small amount of iron, ferrous salt, silver sulfate and the like coexist, or a disuccinic peroxide, diglutar Examples thereof include dibasic acid peroxides such as acid peroxide, azobisisobutylamidine hydrochloride, and organic initiators such as azobisisobutyronitrile.

The amount of the polymerization initiator to be used can be appropriately changed according to the kind thereof, the emulsion polymerization conditions and the like, but is usually 0.005 per 100 parts by mass of the monomer to be emulsion-polymerized.
About 0.5 part by mass is preferred. Further, these polymerization initiators may be added all at once, or may be added in portions as needed.

In order to raise the pH of the emulsion, p
An H adjuster may be used. Examples of the pH adjusting agent include inorganic bases such as sodium carbonate, potassium carbonate, sodium hydrogen orthophosphate, sodium thiosulfate, and sodium tetraborate, and organic bases such as triethylamine, triethanolamine, dimethylethanolamine, and diethylethanolamine. Is exemplified.

The amount of the pH adjuster to be added is generally about 0.05 to 2 parts by weight, preferably about 0.1 to 2 parts by weight, per 100 parts by weight of the emulsion polymerization medium. The higher the pH, the higher the polymerization rate tends to be.

The starting temperature of the emulsion polymerization is selected as appropriate depending on the type of the polymerization initiator.
A temperature of 100 ° C, especially about 10 to 90 ° C, is preferably employed. The polymerization temperature is about 20 to 120 ° C. The reaction pressure can be appropriately selected, but is usually 0.1 to 10 M
It is desirable to adopt Pa, especially about 0.2 to 5 MPa.

In the emulsion polymerization of the present invention, additives such as a monomer, water, an emulsifier, a polymerization initiator and the like may be charged as they are and polymerization may be carried out. For the purpose of improving various properties such as stability and gloss of the coating film, the emulsion may be pre-emulsified using a stirrer such as a homogenizer before the polymerization initiator is added, and then the initiator may be added and polymerized. . Further, the method of charging the monomer is a method of charging the entire amount of the monomer at a time, a method of continuously charging the entire amount of the monomer, and a method of charging the entire amount of the monomer separately. Various methods can be adopted, such as a method, a method in which a part of the monomer is charged and reacted first, and then the remaining is divided or continuously charged. In the case of divisional addition, the monomer composition may be different.

The fluorocopolymer of the present invention is obtained by further emulsifying a monomer having the same combination and composition as the particles, in the presence of particles of the fluorocopolymer which have been polymerized in advance. It may be polymerized. By pre-existing copolymer particles in water in this way, gaseous monomers are easily absorbed, and the polymerization rate is improved. In this case, the stability of the dispersion liquid can be further improved by performing emulsion polymerization after diluting the particles of the fluorine-based copolymer that has been polymerized in advance.

In this case, it is desirable to carry out the polymerization at a ratio of 100 to 10,000 parts by mass of the mixture of monomers with respect to 100 parts by mass of the fluorine-based copolymer particles previously charged during the polymerization. If the ratio of the particles of the fluorine-based copolymer to be charged in advance is too small, the effect of improving the polymerization rate is small, and if it is too large, the yield of the aqueous dispersion obtained by one polymerization operation is reduced, which is not economical.

To further improve the gas absorption of the gaseous monomer into the aqueous dispersion, alcohols such as methanol, ethanol, isopropanol, n-butyl alcohol, isobutyl alcohol and t-butyl alcohol; A hydrophilic organic compound such as an alkylene glycol such as glycol or propylene glycol may be added during polymerization. In this case, the addition amount is preferably about 0.1 to 10% by mass relative to the water of the aqueous dispersion. More preferably, it is 1 to 5% by mass.

If the addition amount is less than this, the gas absorbing effect is small, and if it is too large, the viscosity of the aqueous dispersion increases, making it difficult to form a coating, which is not preferable.

In the present invention, excellent coating film properties can be obtained by emulsion-polymerizing a monomer mixture containing a (meth) acrylic acid alkyl ester or the like as a main component, based on the above-mentioned fluorine-based copolymer. To give an aqueous dispersion of a fluorinated copolymer that imparts the following.

That is, first, as defined in claim 3, (a) a polymerized unit based on a fluoroolefin, (b) a polymerized unit based on propylene, and (c) a polymerized unit based on ethylene and / or Or (d) an alkyl (meth) acrylate having an alkyl group having 1 to 18 carbon atoms in the presence of 100 parts by mass of particles of a fluorocopolymer (X1A) containing (d) a polymerized unit based on butylene. (Meth) having an ester and (i) a hydroxyl group and having a molecular weight of less than 250
5 to 100 parts by mass of a radical polymerizable monomer mixture (Y1A) containing an acrylate ester is emulsion-polymerized to form composite particles (A3) (the composite particles are also referred to as core-shell type particles). It is.

More preferably, a complex treatment of a fluorine-based copolymer / alkyl (meth) acrylate-based copolymer can be performed. Here, the “composite treatment” means that the base fluoropolymer particles and the (meth) acrylate copolymer particles each contain a reactive group that can be bonded to each other, and are used during emulsion polymerization. This is a treatment in which part or all of the copolymers are bonded to each other to suppress phase separation.

A coating film formed by using the aqueous dispersion of the above-mentioned complexing treatment as a coating binder is such that when the applied coating film is heated and the aqueous solvent is dried and removed, the reactive groups of both copolymers are removed. It is believed that further binding occurs and the fusion is strong.
Therefore, the transparency, mechanical strength, and the like of the coating film can be further improved while maintaining the characteristics such as the weather resistance of the base fluoropolymer.

As described above, by subjecting the particles of the base fluorocopolymer to a complex treatment with a (meth) acrylic acid ester or the like, the mechanical properties of the fluorocopolymer are maintained while maintaining the properties such as weather resistance. Stability, chemical stability, film forming property, transparency, pigment dispersibility, and workability can be further improved.

That is, second, as defined in claim 4, (a) a polymerized unit based on a fluoroolefin, (b) a polymerized unit based on propylene, (c) a polymerized unit based on ethylene, and / or 100% of particles of a fluorocopolymer (X2A) containing (d) a polymerized unit based on butylene and (j) a polymerized unit based on a vinyl monomer having a reactive group which does not react with a hydroxyl group in the following (i). In the presence of parts by mass, (h) an alkyl (meth) acrylate having 1 to 18 carbon atoms in the alkyl group, (i) a (meth) acrylate having a hydroxyl group and a molecular weight of less than 250, and ( l) A radii containing (meth) acrylic acid and / or (meth) acrylic acid ester having a reactive group other than a hydroxyl group, which can react with the reactive group of (j) to form a bond. Le polymerizable monomer mixture (Y2
5 to 100 parts by mass of (A) are subjected to emulsion polymerization to form composite particles (A).
4).

In the present invention, the monomer mixture (Y
2A) further has (k) a hydrophilic group and a molecular weight of 25
It may contain 0 or more (meth) acrylic acid esters (however, excluding (1) above).

The ratio of the monomer mixture (Y1A or Y2A) is determined by the ratio of the base fluorine-containing copolymer (X1A or X1A).
5 to 100 parts by mass, preferably 10 to 80 parts by mass, more preferably 20 parts by mass per 100 parts by mass of the particles of 2A).
５０50 parts by mass. Therefore, in order to obtain the composite particles (A3 or A4), 5 to 100 parts by mass of the above (h) is added to the reaction vessel in the presence of 100 parts by mass of the base fluorocopolymer (X1A or X2A). ), A monomer mixture (Y1A or Y2A) mainly containing (meth) acrylic acid alkyl ester or the like may be charged and emulsion polymerization may be performed.

The alkyl (meth) acrylate (h) has an alkyl group having 1 to 18 carbon atoms.
For example, methyl (meth) acrylate,
Ethyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate,
N-Amyl (meth) acrylate, isoamyl (meth) acrylate, n-hexyl (meth) acrylate, (meth)
Examples thereof include isohexyl acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, and cyclohexyl (meth) acrylate. Among them, in particular, an alkyl group having 1 to 5 carbon atoms (meth)
Acrylic esters are preferred.

The preferred ratio of the above (h) in the monomer mixture (Y1A or Y2A) is 20 to 95% by mass. More preferably, the content is 30 to 80% by mass. (H)
If the ratio is too small, the weather resistance and gloss of the coating film will be poor, and if it is too large, the transparency and mechanical strength of the coating film will tend to be poor.

The above (i) having a hydroxyl group and having a molecular weight of 250
Examples of the less than (meth) acrylate include hydroxyalkyl (meth) acrylates having 1 to 10 carbon atoms in the hydroxyalkyl group, such as hydroxyethyl (meth) acrylate and 2 (meth) acrylate. -Hydroxypropyl, 4-hydroxybutyl (meth) acrylate, 5-hydroxypentyl (meth) acrylate and the like. Among them, especially carbon number 1
(Meth) acrylic esters having from 5 to 5 hydroxyalkyl groups are preferred. When the molecular weight is 250 or more,
When forming a crosslinked coating film by reacting with the self-emulsifying polyisocyanate compound (B), the hardness of the coating film is insufficient.

The preferred ratio of (i) in the monomer mixture (Y1A or Y2A) is 1 to 60% by mass. More preferably, it is 5 to 50% by mass. If the proportion of (i) is too small, crosslinking of the coating film becomes insufficient and the solvent resistance and the like deteriorate, and if it is too large, the weather resistance and the like of the coating film tend to deteriorate.

(L) As (meth) acrylic acid and / or (meth) acrylate having a reactive group other than a hydroxyl group, which can react with the reactive group of the above (j) to form a bond. For example, (meth) acrylate having a reactive group selected from the group consisting of a carboxyl group, an epoxy group (glycidyl group), a hydrolyzable silyl group and an amino group can be used.

The (l) includes (meth) acrylic acid, 2-carboxyethyl (meth) acrylic acid, glycidyl (meth) acrylate, γ- (meth) acryloyloxypropyltrimethoxysilane, γ- (meth) Acryloyloxypropyltriethoxysilane, γ- (meth) acryloyloxypropyldimethoxysilane, γ
-(Meth) acryloyloxypropyltriisopropenyloxysilane, (meth) acrylic acid dimethylaminoethyl ester and the like.

Since the above (1) reacts with the reactive group of the above (j) to form a bond, it is preferably used in a ratio of 0.5 to 5 times the number of moles of the above (j). Desirably, a ratio of 0.8 to 4 times is particularly preferable. Further, a preferable ratio of the (l) in the monomer mixture (Y2A) is 1 to
It is 60% by mass, more preferably 5 to 50% by mass.

(K) having a hydrophilic group and having a molecular weight of 2
As the hydrophilic group of 50 or more (meth) acrylates, a nonionic hydrophilic group is usually preferable. Above all, a nonionic hydrophilic group such as a polyoxyethylene group or a polyoxypropylene / polyoxyethylene group is preferred from the viewpoint of the influence on the strength of the hydrophilic property and the physical properties of the coating film. In (k), the number of repeating units such as a polyoxyethylene group and a polyoxypropylene / polyoxyethylene group as hydrophilic groups is preferably 4 or more and 50 or less from the viewpoint of polymerizability and durability. . Specific examples of the (k) include, for example, NK-ester M90G (trade name: manufactured by Shin-Nakamura Chemical Co., Ltd.). Further, the (k) (meth) acrylic acid ester having a hydrophilic group (excluding the above (1)) has a molecular weight of 250 or more. When it is less than 250, the aqueous dispersion stability of the composite particles (A4) is reduced.

The preferred ratio of (k) in the monomer mixture (Y2A) is 0.1 to 20% by mass.
More preferably, it is 0.5 to 15% by mass. If the proportion of (k) is too small, the stability of the aqueous dispersion will be poor, and if it is too large, the water resistance of the coating will tend to be poor.

Further, for the purpose of improving the gloss and the like of the coating film,
Along with the above (h) to (k), other monomers copolymerizable with the above (h) to (k), for example, aromatic vinyl compounds such as styrene and α-methylstyrene, (meth) acrylonitrile, An amide compound such as (meth) acrylamide may be used in an amount of 50% by mass or less, preferably 30% by mass or less based on the monomer mixture (Y1A or Y2A).

The conditions for the emulsion polymerization of the monomer mixture (Y1A or Y2A) can be adopted according to the conditions for the emulsion polymerization for the above-mentioned fluorine-based copolymer (A1 or A2).

The composite particles (A3 or A4) in the present invention
Is preferably in the range of 40 to 150 ° C, more preferably 60 to 120 ° C. If the melting point is too low, the hardness of the coating film will be insufficient. If the melting point is too high, sufficient fluidity will not be obtained at the time of heating and the appearance of the coating film will be impaired.

The glass transition temperature of the composite particles (A3 or A4) is preferably in the range of -20 ° C to 80 ° C, more preferably 0 to 70 ° C. If the glass transition temperature is too low, the film will be tacky, and if it is too high, the flexibility of the film will be impaired.

The Q value, which is an index of the molecular weight of the composite particles (A3 or A4), is preferably in the range of 0.1 to 10,000. More preferably 1 to 1,000
And more preferably 10 to 500. When the Q value is less than 0.1, the fluidity of the particles is reduced,
The smoothness of the coating film tends to decrease. If it is larger than 10,000, the mechanical strength of the coating film is impaired.

The average particle diameter of the composite particles (A3 or A4) is preferably in the range of 50 nm to 300 nm. More preferably, it is 70 to 200 nm. When the particle diameter is less than 50 nm, mechanical stability is reduced,
Also, the film-forming properties tend to decrease. If it is larger than 300 nm, sedimentation stability, thermal stability, mechanical stability, and chemical stability are impaired. However, if it is less than 30% by mass, particles having a particle diameter outside the range may be mixed.

The water-based paint composition of the present invention is obtained by blending the above-mentioned fluorine-based copolymer (A1 or A2) or the above-mentioned composite particles (A3 or A4) with a self-emulsifiable polyisocyanate compound (B). Characterized in that:
Here, a self-emulsifying polyisocyanate compound (B)
The term “compound” does not require an emulsifier or is a compound that can be emulsified and dispersed in water with a small amount of an emulsifier. Thus, the aqueous coating composition can form a crosslinked structure from the NCO group in the polyisocyanate compound (B) and the hydroxyl group in the fluorine-based copolymer and the like. A coating film having excellent solvent resistance can be formed.

Here, the polyisocyanate compound as a raw material of the above (B) includes aliphatic polyisocyanates such as hexamethylene diisocyanate;
-Phenylene diisocyanate, 2,4- or 2,6-
Tolylene diisocyanate, diphenylmethane-4,4
Aromatic polyisocyanates such as diisocyanate, naphthalene-1,5-diisocyanate, 4,4-diisocyanate-3,3-dimethyldiphenyl; bis-
Alicyclic polyisocyanates such as (isocyanatecyclohexyl) methane and isophorone diisocyanate;
Examples include crude polyisocyanates such as crude tolylene diisocyanate and crude diphenylmethane diisocyanate; and modified polyisocyanates such as carbodiimide-modified diphenylmethane diisocyanate, polyol-modified diphenylmethane diisocyanate, and polyol-modified hexamethylene diisocyanate.

The polyisocyanate compound may be a dimer or trimer of a buret type, isocyanurate ring type or uretdione type, or may be obtained by reacting an isocyanate group with a blocking agent. Or blocked isocyanates. Examples of the blocking agent include alcohols, phenols, caprolactams, oximes, active methylene compounds and the like. In addition, since blocked polyisocyanates usually do not cure unless the temperature is 140 ° C. or higher, it is preferable to use unblocked polyisocyanates when curing at a lower temperature.

The self-emulsifiable polyisocyanate compound (B) used in the present invention is, for example, a prepolymer obtained by reacting a hydrophilic polyoxyalkylene with the above-mentioned polyisocyanate compound. Here, the hydrophilic polyoxyalkylenes to be subjected to the reaction are preferably those having at least one isocyanate-reactive group such as a hydroxyl group and having a molecular weight of 200 to 40,000. Particularly preferred are polyoxyalkylene glycols such as polyoxyalkylene polyol or polyoxyalkylene monool having a molecular weight in the range of 300 to 15,000. If the molecular weight is too small, the self-emulsifying property is not sufficiently achieved, and if the molecular weight is too large, the self-emulsifying property is good, but the stability in water is poor, and the crystallinity is high. Storage stability decreases, and turbidity occurs. As the polyoxyalkylene chain, those in which all or many of them are oxyethylene groups are preferable from the viewpoint of hydrophilicity.

The reaction between the polyisocyanate and the polyoxyalkylene glycol is carried out by using a catalyst such as a tertiary amine, an alkyl-substituted ethyleneimine, a tertiary alkylsulfine, a metal alkylacetonate, or a metal salt of an organic acid. The reaction can be carried out in the presence, if necessary, in the presence of a promoter at a temperature of 100 ° C. or lower. In this reaction, it is preferable that the amount of the residual isocyanate groups is adjusted to 10 to 24% by mass. If the amount of the residual isocyanate group is small, the reactivity with the fluorine-based copolymer may decrease, which is not preferable. Further, since a large amount of isocyanate compound is required to achieve a sufficient degree of crosslinking, the weather resistance of the coating film may be adversely affected, which is not preferable. On the other hand, if the amount of the residual isocyanate groups is too large, it is difficult to form a stable emulsion, which is not preferable. Incidentally, such a self-emulsifying isocyanate compound,
It is described in Japanese Patent Publication No. 4-15270.

The aqueous coating composition of the present invention can be prepared by mixing the above-mentioned fluorine-based copolymer and a self-emulsifying polyisocyanate compound. The mixing method is as follows. That is, a method of adding a self-emulsifying polyisocyanate compound to an aqueous dispersion of a fluorine-based copolymer and stirring the mixture, or mechanically dispersing the polyisocyanate compound in water, followed by mixing with the aqueous dispersion of a fluorine-based copolymer And so on.

Further, an aqueous dispersion of a fluorocopolymer is
When adding and dispersing the self-emulsifiable polyisocyanate compound, a more stable dispersion can be obtained by adding an emulsifier. As the emulsifier, those used at the time of the polymerization described above are used. However, those having an ionic property, particularly an active hydrogen atom, are not preferable because they react during dispersion to increase the viscosity or decrease the dispersibility. Therefore, nonionic emulsifiers, especially emulsifiers having polyoxyethylene chains, are preferred.

Further, a fluorine-based copolymer or the like (A1 to A
The mixing ratio of 4) and the self-emulsifying polyisocyanate compound (B) is not particularly limited, but may be NCO / O
The ratio of H (molar ratio) (where NCO is the molar amount of NCO in the polyisocyanate compound and OH is the molar amount of OH in the fluorine-based copolymer) is 0.1 to 0.1.
It is preferable to set the range of 2.0. NCO
If the / OH (molar ratio) is too large, an excess of isocyanate groups may remain in the coating film, or may react with moisture to generate air bubbles, which may cause defects in the coating film. On the other hand, if NCO / OH (molar ratio) is too small, the effect of crosslinking cannot be sufficiently obtained, which is not preferable. In particular, it is preferable that NCO / OH (molar ratio) be in the range of 0.5 to 1.5.

The aqueous dispersion according to the present invention, when used as a paint base and formed into a paint, has good adhesion, weather resistance and chemical resistance to inorganic and organic substrates to be coated. In order to further improve the stain resistance in addition to the film-forming properties, an inorganic silicon compound and / or an organic silicon compound (hereinafter, referred to as an organic silicon compound) (Abbreviated as inorganic / organosilicon compound). Examples of such inorganic silicon compounds include water-soluble silicates such as water glass and water-dispersible colloidal silica.

Examples of the water-soluble silicate include those represented by the formula (I): T ₂ O · kSiO ₂ (I) (wherein T is an alkali metal or N (CH ₂ CH ₂ O)
_{H) 4, -N (CH 2} OH) 4, -N (CH 2 CH 2 OH)
₃ or -C (NH ₂₎ a ₂ NH, k is 0.5 to 5
It is. )). The water-soluble silicate may or may not have water of crystallization.

Examples of the colloidal silica include, for example, sodium removal from water glass (ion exchange method, acid decomposition method,
Peptization), and the primary particle diameter is 4 to
It has a thickness of 150 nm, preferably 5 to 50 nm, and is usually supplied as an aqueous dispersion, which can be used as it is in the present invention. (For example, trade name Snowtex-O or Snowtex 20: manufactured by Nissan Chemical Industries, Ltd.)

Further, specific examples of the organosilicon compound include, for example, tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, methyltrimethoxysilane, methyltriethoxysilane, dimethyldimethoxysilane and the like.

The ratio of the solid content of the fluorine-based copolymer or the like in the aqueous coating composition of the present invention to the compounded inorganic / organic silicon compound is 100 parts by mass of the solid / inorganic / organic silicon compound. The silicon compound is 0.1 to 100 parts by mass. More preferably, it is in the range of 1 to 50 parts by mass. When the ratio of the inorganic / organic silicon compound is smaller than 0.1, the non-staining property of the surface of the coating film obtained may be insufficient,
If the thickness exceeds, defects such as cracks are likely to occur in the coating film due to lack of flexibility at the time of forming the coating film or over time.

The water-based paint composition of the present invention can be used as a water-based paint as it is as a paint binder. If necessary, a coloring agent, a plasticizer, an ultraviolet absorber, an ultraviolet stabilizer, a leveling agent, a defoaming agent, Additives usually added to aqueous paints, such as a pigment dispersant, a thickener, an anti-cissing agent, an anti-burr agent, and a curing agent, may be appropriately selected and mixed. Furthermore,
A metallic pigment such as an aluminum paste may be used.

In the present invention, the aqueous coating composition according to any one of the above (1) to (6) may be added to an ultraviolet absorbent,
A water-based coating composition containing at least one selected from the group consisting of a film-forming aid and a thickener can be exemplified as a preferable one.

Examples of the coloring agent include dyes, organic pigments, inorganic pigments and the like. Examples of the plasticizer include conventionally known plasticizers, for example, low molecular weight plasticizers such as dioctyl phthalate, and high molecular weight plasticizers such as vinyl polymer plasticizers and polyester plasticizers.

Examples of the ultraviolet absorber include 2-hydroxybenzophenone, 2-hydroxy-4-benzyloxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2-hydroxy-5-chlorobenzophenone,
2-aminobenzophenone, high molecular weight modified bensophenone (for example, trade name: T-5, manufactured by Adeka Argus Co., Ltd.)
Benzophenones such as 7); 2- (2′-hydroxy-)
5′-t-butylphenyl) benzotriazole, 2-
(2′-hydroxy-5′-t-butylphenyl) -5
-Chlorobenzotriazole, 2- (2'-hydroxy-5'-methoxyphenyl) benzotriazole, 2-
Benzotriazoles such as (2'-hydroxy-3 ', 5'-dineopentylphenyl) benzotriazole and high molecular weight modified benzotriazole (for example, trade names: Tinuvin 900, Tinuvin 1130, manufactured by Ciba Specialty Chemicals) And the like.

As the ultraviolet stabilizer, a high molecular weight modified hindered amine (for example, trade name: MARK LA 57, 62, 63, 67, 6 manufactured by Adeka Argus Co., Ltd.)
8), Tinuvin 292 (trade name) manufactured by Ciba Specialty Chemicals, and the like.

Examples of the film-forming aid include dipropylene glycol-n-butyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether,
Polyhydric alcohol monoalkyl ethers such as diethylene glycol monobutyl ether and organic acid esters are used. Examples of the thickener include a cellulose thickener represented by hydroxyethylcellulose and carboxymethylcellulose, a urethane thickener, and a polycarboxylic acid thickener.

In order to improve the stability of the aqueous coating composition of the present invention, sodium carbonate, potassium carbonate,
A pH adjuster such as sodium orthophosphate, triethylamine and triethanolamine may be added.

[0122]

EXAMPLES The present invention will be specifically described below with reference to synthesis examples and examples, but the present invention is not limited to these examples and the like. The number of parts in the following examples indicates parts by mass unless otherwise specified.

(Synthesis Example 1) (1) 1100 g of ion-exchanged water, 4.75 g of an anionic emulsifier (sodium lauryl sulfate), and a nonionic emulsifier (N-1110; Nippon Emulsifier Co., Ltd.) 24.7 g and t-
39.8 g of butanol was charged, and air was removed by repeating deaeration with a vacuum pump and pressurization with nitrogen gas.
Next, (a) 70.4 g of tetrafluoroethylene,
(B) 8.3 g of propylene, (c) 1.1 g of ethylene,
(E) 4-hydroxybutyl vinyl ether (hereinafter HB
4.1 g) were introduced into the autoclave.

(2) When the temperature in the autoclave reached 65 ° C., the pressure showed 2.42 MPa. Thereafter, 7 mL of a 30% aqueous solution of ammonium persulfate was added to start the reaction. (A) 59.1 mol% of tetrafluoroethylene,
(B) propylene 20.4 mol%, (c) ethylene 2
630 g of a 0.5 mol% mixed gas was continuously added to continue the reaction. In addition, (e) 33 g of HBVE was injected 5
It was added in portions.

After 15 hours, the supply of the mixed gas was stopped, and the autoclave was cooled with water to reach room temperature. Then, unreacted monomers were purged, and the autoclave was opened to release the solid content.
A 5% aqueous dispersion was obtained.

(3) The obtained aqueous dispersion was settled by a centrifugal separator, and the polymer was filtered through a glass filter.
After removing water over 5 hours under reduced pressure of 539 Pa,
The powder was pulverized with an impact hammer mill to obtain a powder of a fluorine-based copolymer. The result of composition analysis of the copolymer by ¹³ C-NMR was as follows: (a) 55 mol% of polymerized units based on tetrafluoroethylene, and (b) polymerized units 19 based on propylene.
Mol%, (c) 19 mol% of polymerized units based on ethylene,
(E) The polymerization unit was 7 mol% based on HBVE. The melting point was 117.2 ° C. Table 1 shows the results.

(Synthesis Example 2) (1) 100 g of ion-exchanged water and potassium carbonate (K ₂ C) were placed in a 2 L stainless steel autoclave equipped with a stirrer.
O ₃₎ 3.2 parts of a nonionic emulsifier (N-1110; manufactured by Nippon Emulsifier Co., Ltd.) 20.7 parts, anionic emulsifiers (sodium lauryl sulfate) 7.3 g, t-butanol 28.4
g, (e) HBVE 8.1 g, (f) vinyl acetate 2.6
g, and air was removed by repeating deaeration with a vacuum pump and pressurization with nitrogen gas. Next, (a) 69.2 g of tetrafluoroethylene and (b) propylene 7.2
g, (c) 2.2 g of isobutylene were introduced into the autoclave.

(2) When the temperature in the autoclave reached 65 ° C., the pressure showed 2.35 MPa. Thereafter, 10 mL of a 30% aqueous solution of ammonium persulfate was added to start the reaction. While maintaining the pressure as the pressure drops,
630 g of a mixed gas of (a) 78 mol% of tetrafluoroethylene, (b) 19 mol% of propylene, and (c) 3 mol% of isobutylene was continuously added to continue the reaction. Also, a mixed solution of (e) 86.3 g of HBVE and (f) 64 g of vinyl acetate was added in five portions through a press-fit tube.

(3) After 12 hours, supply of the mixed gas was stopped, and the autoclave was cooled with water to reach room temperature. Then, unreacted monomers were purged, and the autoclave was opened to obtain a concentration of 37.
A 2% aqueous dispersion was obtained. The obtained aqueous dispersion was settled by a centrifugal separator, the polymer was filtered with a glass filter, and water was removed under a reduced pressure of 133 Pa for 5 hours, and then pulverized with an impact hammer mill to obtain a fluorocopolymer. Was obtained. The results of compositional analysis of this copolymer by ¹³ C-NMR were as follows: (a) 52 mol% of polymerized units based on tetrafluoroethylene, (b) 25 mol% of polymerized units based on propylene, and (e) polymerized units based on isobutylene. 5
Mol%, (f) 10 mol% of polymerized units based on vinyl acetate, and (e) 8 mol% of polymerized units based on HBVE. The melting point was 61.4 ° C. Table 1 shows the results.

(Synthesis Examples 3 to 5) The monomer composition used in the emulsion polymerization was changed as shown in Table 1, and otherwise, an aqueous dispersion of a fluorine-based copolymer was prepared according to the method described in Synthesis Examples 1 and 2. Obtained.

(Synthesis Example 6) A 500-mL glass flask equipped with a thermometer, a stirrer, a reflux, and a condenser was prepared as shown in Table 1.
300 g of the aqueous dispersion obtained in Synthesis Example 5 was prepared (the amount of the fluorine-based copolymer in the dispersion was 116 g).
Heated to 80 ° C. When the temperature reached 80 ° C., (i) 3.2 g of 2-hydroxyethyl methacrylate,
(H) 31.5 g of t-butyl methacrylate, 0.3 g of nonionic emulsifier (N-1110; manufactured by Nippon Emulsifier Co.), 0.02 of anionic emulsifier (sodium lauryl sulfate)
g of water and 29.7 g of water were added dropwise over 1 hour. Immediately thereafter, a 2% aqueous solution of ammonium persulfate 1
mL was added to start the reaction. After a reaction time of 3 hours, the temperature in the flask was raised to 90 ° C., and the reaction was further carried out for 1 hour to complete the polymerization. A composite aqueous dispersion was obtained. Table 2 shows the results.

(Synthesis Examples 7 to 11) The composition of the monomers used in the emulsion polymerization was changed as shown in Table 2, and otherwise, a composite aqueous dispersion was obtained according to the method described in Synthesis Example 6. .

[0133]

[Table 1]

[0134]

[Table 2]

The melting point was measured by using a scanning differential calorimeter (DS).
The exothermic peak when the sample was heated at 10 ° C./min was determined by C), and the temperature at that time was determined as the melting point. In the case where the distribution of the melting point peaks was wide, the lowest point of the downwardly convex portion was defined as the melting point. The glass transition temperature was defined as the point where two tangents intersect at a portion where a rapid change in the temperature gradient occurs in the DSC temperature rise curve. In addition, in each composition of Table 1, for example, the composition of tetrafluoroethylene is “72/55”, which means that the composition of the molecule “72” is 72 mol% in the feed monomer, and the denominator is “55” indicates that the polymerized units based on tetrafluoroethylene in the copolymer are 55%.

Example 1 71 parts of an aqueous dispersion of the fluorocopolymer obtained in Synthesis Example 1 and 24 g of self-emulsifying polyisocyanate (AQ-200: NCO content: 12%, manufactured by Nippon Polyurethane Industry Co., Ltd.) , Lithium silicate (Si
O ₂ / Li ₂ O molar ratio 4.5: lithium silicate 45,
3.5 g of Nissan Chemical Industries, 5.4 g of a film-forming auxiliary, 0.3 g of a thickener, 0.8 g of a dispersant, 0.6 g of a defoamer, and 10.3 g of ion-exchanged water are shown in Table 3. And a clear paint formulation was performed. The film-forming aid was Cs-12 (manufactured by Chisso), the thickener was Leobis CR (manufactured by Hoechst Gosei),
The dispersant is Noscosperse 44-C (manufactured by San Nopco), and the antifoaming agent is FS Antifoam 90 (manufactured by Dow Corning).

(Examples 2 to 4) The clear paints shown in Table 3 were prepared in the same manner as in Example 1 except that the aqueous dispersions of the fluorocopolymers were obtained according to Synthesis Examples 2, 3, and 4, respectively. Formulation was performed.

Comparative Example 1 A clear coating composition shown in Table 3 was prepared in the same manner as in Example 1 except that the aqueous dispersion of the fluorocopolymer was obtained according to Synthesis Example 5.

Example 5 70 parts of an aqueous dispersion of the fluorocopolymer obtained in Synthesis Example 6, 18 g of self-emulsifying polyisocyanate (AQ-100: NCO content: 17%, manufactured by Nippon Polyurethane Industry Co., Ltd.) , Lithium silicate (Si
O ₂ / Li ₂ O molar ratio 4.5: lithium silicate 45,
3.5 g of Nissan Chemical Industry Co., Ltd., 1.0 g of ultraviolet absorber,
5.4 g of a film-forming auxiliary, 0.3 g of a thickener, 0.8 g of a dispersant,
The clear paint shown in Table 4 was prepared by using 0.6 g of the defoamer and 10.3 g of ion-exchanged water in the amounts shown in Table 3. In addition,
The ultraviolet absorber was Tinuvin 900 (manufactured by Ciba Specialty Chemicals), the film-forming aid was butyl carbitol acetate, the thickener was Leobis CR (manufactured by Hoechst Gosei), and the dispersant was Noscosperse 44-C. (Manufactured by San Nopco) and the antifoaming agent are FS Antifoam 90 (manufactured by Dow Corning).

(Examples 6 to 9) Table 4 was prepared in the same manner as in Example 1 except that the aqueous dispersions of the fluorocopolymer were obtained according to Synthesis Examples 7, 8, 9, and 10, respectively. The clear paint formulation shown was performed.

Comparative Example 2 Example 1 was repeated except that the aqueous dispersion of the fluorocopolymer was obtained according to Synthesis Example 11.
In the same manner as described above, the clear paint shown in Table 4 was blended.

(Coating Film Test) The paints obtained in Examples 1 to 9 and Comparative Examples 1 and 2 were applied to a slate plate with an acrylic emulsion primer (Bonflon aqueous primer S: manufactured by Asahi Glass Coat & Resin Co.) On the painted specimen
Apply by air spray to a dry film thickness of 40 μm,
The test piece was obtained by drying at 90 ° C. for 40 minutes. Blocking test, solvent resistance test, weather resistance,
Water resistance, stain resistance, adhesion and transparency tests were performed.
The results are shown in Tables 3 and 4.

The test method was as follows. Blocking resistance test: Two test pieces were placed on top of each other,
After a load of 0.05 MPa was applied and left at 50 ° C. for 1 hour, the state of the coating film when the test piece was separated was observed.
○ indicates no change in the coating film surface, △ indicates that the coating film was partially damaged, and x indicates that the entire coating film was damaged.

Solvent resistance test: The state of the coating film after rubbing 50 times with gauze impregnated with xylene was observed.
○ indicates no change in the coating film surface, Δ indicates that the gloss of the coating film surface was reduced, and x indicates that the coating film was melted.

Evaluation of weather resistance: When the gloss was significantly reduced after 3000 hours in a QUV test using a fluorescent ultraviolet light weather tester manufactured by Q Panel Co., it was evaluated as x, and when the gloss was not significantly reduced, it was evaluated as ○.

Water resistance evaluation: After immersion in warm water of 60 ° C. for one week, the coating was evaluated for blistering or peeling. A sample without swelling or peeling was rated as "O", and a sample with swelling or the like was rated as "x".

Stain resistance: Exposure was performed outdoors at 45 ° on the south side for 1 year.
Those exceeding 5 were evaluated as x.

Transparency: The test piece was heated at 200 ° C. for 10 minutes, and a completely transparent sample was evaluated as ○, a slightly turbid sample as Δ, and a fairly opaque sample as ×.

Adhesion: A tape peeling test was performed based on JIS K5400.剥離 indicates that no complete peeling was observed, △ indicates partial peeling, and x indicates fairly peeling.

[0150]

[Table 3]

[0151]

[Table 4]

[0152]

As described above, the composition for water-based coating of the fluorocopolymer of the present invention provides a coating film having excellent blocking resistance, solvent resistance, weather resistance, water resistance, stain resistance, transparency and adhesion. And is extremely useful as a weather-resistant aqueous paint.

Since the fluorocopolymer composition of the present invention is basically based on a stable aqueous dispersion without using an organic solvent, it is subject to restrictions such as solvent regulations. And can be applied to a wide range of applications. For example, it is particularly useful for weather-resistant coating of exterior inorganic building materials such as glass, metal and cement.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takao Hirono 10 Goi Kaigan, Ichihara City, Chiba Prefecture Asahi Glass Co., Ltd. F-term (reference) 4J034 BA03 DA01 DA05 DP03 DP04 DP12 DP15 DP17 DP18 DQ08 DQ15 DQ22 HB08 HB09 HC03 HC12 HC13 HC17 HC22 HC35 HD03 HD05 HD07 JA42 MA04 MA17 RA07 4J038 BA092 DG002 DG191 DG271 DG281 DG291 DG301 GA02 GA03 GA06 GA07 GA09 GA12 GA15 HA156 HA446 HA456 JA26 JA33 JA35 JB35 JC32 KA07 KA08 MA08 MA10 MA14 NA15 NA05 NA04 NA05

Claims (7)

[Claims] 1. A polymerization unit based on (a) a fluoroolefin, (b) a polymerization unit based on propylene, (c) a polymerization unit based on ethylene and / or (d) a polymerization unit based on butylene, and (e) a hydroxyl group. Has a molecular weight of 250
A fluorine-based copolymer (A1) having a melting point in the range of 40 to 150 ° C., and a self-emulsifying polyisocyanate compound ( And B) are dispersed in water. (2) a polymerization unit based on fluoroolefin, (b) a polymerization unit based on propylene, (c) a polymerization unit based on ethylene, and / or (d) a polymerization unit based on butylene, and (e) a hydroxyl group. A polymerized unit based on a vinyl monomer having a molecular weight of less than 250; and (f) a polymerized unit based on at least one selected from the group consisting of vinyl esters, vinyl ethers, isopropenyl ethers and allyl ethers, and / or (g). A fluorine-based copolymer (A2) having a hydrophilic group and a polymerization unit based on a macromonomer having a molecular weight of 250 or more, the melting point of which is in the range of 40 to 150 ° C .; An aqueous coating composition, wherein the emulsifiable polyisocyanate compound (B) is dispersed in water. 3. A polymerized unit based on (a) a fluoroolefin, (b) a polymerized unit based on propylene, and (c)
In the presence of 100 parts by mass of particles of a fluorocopolymer (X1A) containing a polymerized unit based on ethylene and / or a polymerized unit based on (d) butylene, (h) the alkyl group has 1 to 18 carbon atoms. Emulsifies 5 to 100 parts by mass of a radically polymerizable monomer mixture (Y1A) containing (meth) acrylic acid alkyl ester and (i) a (meth) acrylic acid ester having a hydroxyl group and a molecular weight of less than 250. A composition for water-based paint, wherein composite particles (A3) obtained by polymerization and a self-emulsifying polyisocyanate compound (B) are dispersed in water. 4. A polymerized unit based on (a) a fluoroolefin, (b) a polymerized unit based on propylene, (c) a polymerized unit based on ethylene and / or (d) a polymerized unit based on butylene, and (j) (h) in the presence of 100 parts by mass of particles of a fluorocopolymer (X2A) containing a polymerized unit based on a vinyl monomer having a reactive group that does not react with a hydroxyl group of i), (h) the number of carbon atoms of the alkyl group Reacts with 1 to 18 alkyl (meth) acrylates, (i) a (meth) acrylate having a hydroxyl group and a molecular weight of less than 250, and (l) a reactive group of (j) to bind to A radical polymerizable monomer mixture containing a (meth) acrylic acid and / or a (meth) acrylic acid ester having a reactive group other than a hydroxyl group,
A composition for water-based paint, wherein composite particles (A4) obtained by emulsion polymerization of 5 to 100 parts by mass of A) and a self-emulsifying polyisocyanate compound (B) are dispersed in water. object. 5. The monomer mixture (Y2A) further comprises (k) a hydrophilic group, and (meth) having a molecular weight of 250 or more.
The aqueous coating composition according to claim 4, comprising an acrylate ester (except for (1)). 6. The aqueous coating composition according to claim 1, wherein the solid content of the inorganic silicon compound and / or the organic silicon compound is 0 with respect to 100 parts by mass of the solid content in the composition. A water-based coating composition containing 1 to 100 parts by mass. 7. A water-based paint in which at least one selected from the group consisting of an ultraviolet absorber, a film-forming aid and a thickener is blended with the water-based paint composition according to any one of claims 1 to 6. Composition.