JPH083511A - Resin composition for water-repelling coating and production thereof - Google Patents

Abstract

PURPOSE:To provide a water-repelling coating resin composition containing a fluorine-free acrylic resin and fine particles of a specific fluororesin and having improved water-repellency without impairing the characteristics features of acrylic resin as a vehicle resin component. CONSTITUTION:This resin composition contains (A) a fluorine-free acrylic resin and (B) fluororesin fine particles having an average particle diameter of <=5mum and composed of a fluorine-containing (meth)acrylic resin insoluble in the component A and composed mainly of a monomer unit of formula [X is H, Cl, F or methyl; Y is a 1-4C alkylene or group of formula (CH2)nN(R)SO2 (R is H or a 1-4C alkyl; (n) is 1-4); Rf is a 1-15C fluoroalkyl having a perfluoroalkyl on the terminal]. The composition can be produced by the in-situ polymerization of a monomer component composed mainly of the monomer of formula in an organic solvent solution of the component A in the presence or absence of a dispersion stabilizer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solvent-based resin composition for acrylic paints having excellent water repellency and a method for producing the same.

[0002]

2. Description of the Related Art An acrylic resin having a perfluoro group, which is polymerized from a (meth) acrylate having a perfluoroalkyl group (hereinafter sometimes referred to as PFA. The term "(meth) acrylate" means acrylate and methacrylate). The resin is polytetrafluoroethylene (hereinafter referred to as PTF), which is a conventionally known highly water-repellent resin.
It is well known that the surface energy is low and the water repellency is high as compared with olefinic fluororesins such as E) (for example, "Fluorine Resin Handbook", published by Nikkan Kogyo Shimbun).

Utilizing the characteristics of a fluororesin polymerized from such a (meth) acrylate having a perfluoroalkyl group, JP-A-48-4528 or JP-A-50-55630 discloses that: Applications for paint applications are disclosed. Further, in Japanese Patent Application Laid-Open No. 61-14267, an acrylic resin based on an acrylic resin containing a perfluoroalkyl group graft-polymerized with an acrylic resin having a specific degree of polymerization and an acrylic resin is used. There is a disclosure of water and oil repellent paints.

[0004]

On the other hand, it is known that the water repellency of a polymer made of PFA becomes higher as the carbon number of the perfluoroalkyl group becomes larger. It becomes insoluble in general solvents and vehicle components such as epoxy resin and acrylic resin. Therefore, according to the conventional technique, the PF
It was used as a paint by compatibilizing a polymer containing PFA as a polymerization component with a solvent or a vehicle component such as an acrylic resin by incorporating A into the polymerization component and combining it with various copolymerization components. Came.

However, according to the above technique, since P is combined with another polymerization component for solubilization in a solvent or the like, P
The original good water repellency of the FA polymer is sacrificed, and satisfactory performance has not been obtained yet.

The present inventor fully utilizes the high water repellency of a polymer made of PFA, and in order to prevent the good characteristics of the vehicle resin component from being impaired by adding a small amount, the fluorine atom which is the main component of the vehicle is used. It was found that a polymer composed of an acrylic resin and PFA which does not have a polymer is substantially insoluble in each other, and two-phase separated structure having independent domains is preferable. That is, according to the present invention, an acrylic resin-based paint has a two-phase structure in which a polymer obtained by polymerizing an acrylic resin having no fluorine atom, which is a main component of a vehicle, and PFA, which is substantially insoluble in the resin, as a main component. The present invention provides a resin composition for an acrylic water-repellent coating, which enables the formation of such a coating film, and a method for producing the same.

[0007]

That is, the present invention comprises the inventions described below. [1] Acrylic resin (A) containing no fluorine atom and the following general formula (1) which is substantially insoluble in the acrylic resin

Embedded image (Wherein, X represents a hydrogen atom, a chlorine atom, .Y representing a fluorine atom or a methyl group or an alkylene group having 1 to 4 carbon atoms _{- (CH 2) n N (} R) SO 2 -. Represents a wherein R Represents an alkyl group having 1 to 4 carbon atoms or a hydrogen atom, and n is 1
Is an integer of ~ 4. Rf represents a C1-C15 fluoroalkyl group having a perfluoroalkyl group at the terminal. ) Fluorine-containing resin fine particles (B) having an average particle diameter of 5 μm or less and made of a fluorine-containing (meth) acrylic resin mainly containing a perfluoroalkyl group-containing polymerizable monomer unit represented by A resin composition for an acrylic water-repellent coating, which is characterized.

[2] The perfluoro represented by the general formula (1) in an organic solvent in which an acrylic resin (A) containing no fluorine atom is dissolved, in the presence or absence of a dispersion stabilizer. The method for producing a resin composition for an acrylic water-repellent paint according to the above item [1], wherein a monomer component containing an alkyl group-containing polymerizable monomer as a main component is polymerized in situ.

The acrylic water-repellent coating resin composition of the present invention comprises an acrylic resin containing no fluorine atom at the time of forming a coating film and a fluorine-containing (meth) acrylate resin which is substantially insoluble in the acrylic resin. Provides a structure in which the fluororesin phase is uniformly dispersed inside the coating film. In the acrylic resin-based water-repellent coating resin composition of the present invention which is a precursor of the coating film, the average particle diameter of the fluororesin fine particles is 5 μm or less. Average particle size is 5 μm
If it exceeds, it becomes difficult to reduce the leveling property of the coating film and it is difficult to uniformly disperse the fluororesin fine particles in the coating film.

The addition of a dispersion stabilizer to the resin composition for paints makes it possible to improve the dispersion stability of the fluororesin fine particles during storage and to combine the fine particles of the fluororesin fine particles (B) in the coating step. It is also preferable from the viewpoint of suppressing the macro phase separation due to the above and improving the dispersion stability of the fine particles of the fluororesin during storage of the coating material.

The coating composition of the present invention contains a perfluoroalkyl group which is polymerized with PFA as a main component, which is finely divided into fine particles having a particle size of 5 μm or less by crushing or the like with a commercially available ordinary acrylic resin-based coating ( It is also possible to obtain by mixing and dispersing a (meth) acrylate resin. However, obtaining resin fine particles having a particle size of 5 μm or less by pulverization is complicated in the process and is not always preferable industrially.

Further, the fluorine-based resin fine particles (B) are emulsion-polymerized or dispersion-polymerized in an organic solvent to obtain resin fine particles, and the resin fine particle dispersion is mixed with an acrylic resin (A) containing no fluorine atom. The method described below is also useful, but the method described below is a more industrially advantageous method.

That is, in an organic solution in which the acrylic resin (A) containing no fluorine atom is dissolved, a monomer containing the perfluoroalkyl group-containing polymerizable monomer represented by the general formula (1) as a main component. By in-situ polymerizing the components, a perfluoroalkyl group-containing (meth) acrylic resin that is substantially insoluble in the acrylic resin (A) is dispersed in fine particles.

When the monomer to be subjected to in-situ polymerization is insoluble in the solution containing the acrylic resin (A), an emulsifier or a dispersion stabilizer is used to non-aqueously contain the fluorine-containing resin fine particles (B). There are methods of emulsion polymerization and suspension polymerization. Further, the monomer used for the in-situ polymerization is the acrylic resin (A).
In the case of being compatible with a solution containing the above, there is a method of adding a dispersion stabilizer to the solution and performing so-called non-aqueous dispersion polymerization in which the resin is polymerized into fine particles at the same time as the progress of the polymerization.

Each component used in the present invention will be described. The acrylic resin (A) that does not contain a fluorine atom as used herein refers to a paint resin called a conventional acrylic paint, and is obtained by polymerizing from a polymerizable monomer having an acrylate group and / or a methacrylate group. Yes, it means that it is copolymerized with other polymerizable monomers as necessary. Especially when used as a baking type paint,
It is possible to use those obtained by copolymerizing a monomer having a functional group such as a carboxyl group, an epoxy group, a hydroxyl group, or an amino group that easily undergoes a crosslinking reaction.

In the present invention, it is preferable that the acrylic resin (A) containing no fluorine atom is soluble in a usual organic solvent as shown below, but a commercially available solvent-type acrylic paint. You can achieve the purpose by using as it is.

In the present invention, the acrylic resin (A) containing no fluorine atom is used in the form of being dissolved in an organic solvent. As the organic solvent, an inert organic solvent usually used in paints is used. can do. Typical examples of the inert organic solvent include aliphatic hydrocarbon-based pentane, hexane, heptane, octane, cyclohexane, etc., and aromatic hydrocarbon-based benzene, toluene, xylene, etc. Furthermore,
Petroleum ether, tetrahydrofuran, dioxane, methyl ethyl ketone, methyl isobutyl ketone, butanol, isopropanol and the like are also preferably used organic solvents.

The fluororesin fine particles (B) will be described. The following general formula (1) is not substantially dissolved in the acrylic resin (A) containing no fluorine atom.

Embedded image (Wherein, X represents a hydrogen atom, a chlorine atom, .Y representing a fluorine atom or a methyl group or an alkylene group having 1 to 4 carbon atoms _{- (CH 2) n N (} R) SO 2 -. Represents a wherein R Represents an alkyl group having 1 to 4 carbon atoms or a hydrogen atom, and n is 1
Is an integer of ~ 4. Rf represents a C1-C15 fluoroalkyl group having a perfluoroalkyl group at the terminal. ) Fluorine-containing resin fine particles (B) are obtained by polymerizing a monomer component containing a perfluoroalkyl group-containing polymerizable monomer represented by (4) as a main component.

The perfluoroalkyl group-containing polymerizable monomer is not particularly limited as long as it is a compound represented by the above general formula (1) and is water-repellent of the polymerized fluororesin (B). Alternatively, it is particularly preferable that the perfluoroalkyl group contained in Rf has 6 or more carbon atoms because it is not substantially dissolved in the epoxy resin, and one kind or two or more kinds selected from the group is mixed. Can be used. Specific examples of the perfluoroalkyl group-containing (meth) acrylate represented by the above general formula (1) include, but are not limited to, the following compounds.

CH ₂ ═CHCOOCH ₂ (CF ₂ ) _n CF ₃ CH ₂ ═CHCOOCH ₂ CH ₂ (CF ₂ ) _n CF ₃ CH ₂ ═C (CH ₃ ) COOCH ₂ (CF ₂ ) _n CF ₃ CH ₂ ═C (CH ₃ ) COOCH ₂ CH ₂ (CF ₂ ) _{n
CF 3 CH 2 = CHCOOCH 2 CH} 2 N (CH 3) SO
_{2 (CF 2) n CF 3} CH 2 = CHCOOCH 2 CH 2 N (C 3 H 7) SO 2
_{(CF 2) n CF 3 CH} 2 = CFCOOCH 2 (CF 2) n CF 3 CH 2 = CFCOOCH 2 CH 2 (CF 2) n CF 3 ( wherein, n represents an integer of 2 to 14)

The above-mentioned perfluoroalkyl group-containing (meth) acrylate can be polymerized by a conventional radical polymerization. In this case, any method of solution polymerization, dispersion polymerization, suspension polymerization or emulsion polymerization can be used. A method in which it is industrially advantageous to add the monomer together with a polymerization initiator in a resin solution in which an acrylic resin (A) is dissolved in an organic solvent, and carry out non-aqueous suspension polymerization in the presence of a dispersion stabilizer. Is as described above.

As the polymerization initiator, known ones can be used, and as the polymerization initiator, various compounds which generate radicals by thermal decomposition or stimulation of ultraviolet rays can be used. For example, the following may be mentioned. Peroxides such as cumene hydroperoxide, tert-butyl hydroperoxide, dicumyl peroxide, di-tert-butyl peroxide, benzoyl peroxide, acetyl peroxide, methyl ethyl ketone peroxide, lauroyl peroxide,
Azo compounds such as azobisisobutyronitrile (hereinafter referred to as AIBN) having an NN bond, hydrogen peroxide-
Fe ²⁺ , persulfate-NaHSO ₃ , benzoyl peroxide-
Single or dual initiators such as dimethylaniline can be used.

The molecular weight and the molecular weight distribution of the fluorine-containing resin fine particles (B) to be polymerized are controlled by a usual method by appropriately selecting the polymerization conditions and the like.

It is also a useful technique to combine a radical-polymerizable monomer containing a perfluoroalkyl group represented by the above general formula (1) and another radical-polymerizable monomer having no fluorine atom into a copolymer. Is. Acrylic monomers are suitable as these copolymerizable components, and the following can be exemplified. Alkyl (meth) acrylates such as methyl (meth) acrylate, ethyl (meth) acrylate, isobutyl (meth) acrylate, isobutyl (meth) acrylate, alkoxy (meth) acrylate, cyanoethyl (meth) acrylate, acrylamide, (meth) acrylic acid , Glycidyl (meth) acrylate, hydroxyalkyl acrylate and the like.

In the present invention, it is necessary that the fluorine-containing resin fine particles (B), which is an essential component, be substantially insoluble in the acrylic resin (A) and the ordinary organic solvent in which the acrylic resin is dissolved. And in order to obtain high performance by adding a small amount of the fluorine-containing resin fine particles (B), the composition of the fluorine-containing resin fine particles (B) is such that the polymer component containing a fluorine atom-containing monomer is contained. The ratio is 50% by weight or more, and more preferably 70% by weight or more of the fluorine-containing resin fine particles (B).

In the present invention, the composition ratio of the acrylic resin (A) and the fluorine-containing resin fine particles (B) is not particularly limited, but from the viewpoint of stability of the dispersion structure and economy of the composition, the acrylic resin is preferable. The amount of the fluorine-containing resin fine particles (B) is 100 parts by weight or less, more preferably 30 parts by weight or less, relative to 100 parts by weight of the resin (A).

The dispersion stabilizer used in the present invention will be described. As the dispersion stabilizer, for example, an oligomer or a polymer having a perfluoroalkyl group as a hydrophobic group is preferable, but if it contributes to the uniform dispersion of the fluorine-containing monomer or the stability of the dispersion state, Not as long. Specific examples of the dispersion stabilizer preferred in the present invention from commercial products include the following.

(1) MegaFac F-177 (trade name,
Perfluoroalkyl group-containing oligomer manufactured by Dainippon Ink and Chemicals, Inc. (2) Fluorard FC-430 (trade name, Sumitomo 3M
Fluoroaliphatic Polymeric Ester manufactured by Co., Ltd. (3) Unidyne DS-451 (trade name, perfluoroalkyl oligomer manufactured by Daikin Industries, Ltd.) and the like.

The amount of the dispersion stabilizer added is 0.01 to 5 with respect to 100 parts by weight of the acrylic resin (A) solution.
The amount is 0 parts by weight, more preferably 0.1 to 2.0 parts by weight.

If necessary, various components may be further added to the resin composition for paint of the present invention to form a paint.

For example, a dye or pigment can be used as the colorant. For example, titanium oxide, zinc oxide, carbon black, iron black, copper chrome black, copper iron manganese, rouge, zinc iron brown, cadmium red, chrome vermilion, yellow lead, cadmium yellow, zinc chromate, cobalt green. , Chrome green, cobalt chrome green, chrome oxide green, pyridian, cobalt green, navy blue, ultramarine blue, cobalt blue, cobalt violet, manganese violet, manganese violet,
Inorganic pigments such as white carbon, silica white, alumina white, gypsum, precipitated barium sulfate, precipitated barium carbonate, β-naphthol, β-oxynaphthoic acid,
Naphthol NAS type, pyrazolone type, acetoacetate type, phthalocyanine type, anthraquinone type, indigo type, berylylene type, berynone type, dioxazine type, quinacridone type, isoindoline type, metal complex salt type, fluorpin type, quinophthalone type organic type There are pigments, etc.

Further, depending on the purpose of use, talc, mica, calcium carbonate, hydrated alumina, silicon carbide, granular particles such as metal powder, and whiskers such as silicon carbide and aluminum borate may be mixed. Furthermore, as the various components, solvents, viscosity modifiers, dispersants, defoamers, ultraviolet absorbers, antioxidants, light stabilizers, coupling agents and the like commonly used in paints can be used.

[0033]

EXAMPLES The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

Examples 1, 2, 3 Hitaloid 2411S (trade name, manufactured by Hitachi Chemical Co., Ltd., solid content 50% by weight) is a resin solution for acrylic paint which is baked in a 300 cc separable flask equipped with a condenser for cooling. , Aromatic hydrocarbon mixed solvent) 100 g
Then, Florard FC430 (trade name, manufactured by Sumitomo 3M Ltd., a fluorine-based surfactant) was charged as a dispersion stabilizer and the temperature was raised to 100 ° C. Then, β- (perfluorooctyl) as a perfluoroalkyl group-containing polymerizable monomer
A solution obtained by adding 0.1 g of AIBN as a polymerization initiator to 10 g of ethyl acrylate (trade name: light acrylate FA-108 manufactured by Kyoeisha Chemical Industry Co., Ltd.) and dissolving it was added dropwise over 1 hour. Then, polymerization was performed at 100 ° C. for 1 hour. All of the above operations were performed under a nitrogen atmosphere. In this operation, the inside of the system was uniformly transparent at the initial stage of dropping, and became cloudy as the polymerization proceeded. As a result of observing the resin composition with an optical microscope, it was found that the resin composition had a structure in which fine particles of fluororesin having a particle diameter of 1 μm or less were uniformly dispersed. Further, even after the resin composition was allowed to stand at room temperature for one month, the particles did not settle or aggregate, and were stable.

The resin composition comprises 50 parts by weight of acrylic resin (A), 10 parts by weight of fluorine resin fine particles (B),
It is a system consisting of 50 parts by weight of a solvent. This resin composition is
It is designated as F-1. In Examples 2 and 3, PF-1 was diluted with Hitaloid 2411S using the resin composition PF-1, and melamine resin melan 289 (trade name, Hitachi Chemical Co., Ltd. Co., Ltd., solid content 50% by weight), and baked on a steel plate treated with bonderite with a thickness of about 30 μm, and the water repellency of the baked coating film was evaluated by the contact angle to water. The baking was performed at 150 ° C. for 20 minutes. The composition and evaluation results are shown in Table 1.
It was shown to. For the water repellency, the coating film surface and # 1200 polished surface were evaluated.

Examples 4, 5 and 6 In a 300 cc separable flask equipped with a condenser for cooling, Hitaroid 1208C (trade name, manufactured by Hitachi Chemical Co., Ltd., solid content 40% by weight) which is a resin solution for thermoplastic acrylic paint, 100 g of aromatic hydrocarbon mixed solvent) and 1 g of Florard FC430 (trade name, manufactured by Sumitomo 3M Ltd., fluorine-based surfactant) as a dispersion stabilizer were charged.
The temperature was raised to 00 ° C. Then, β- (perfluorooctyl) ethyl acrylate (manufactured by Kyoeisha Chemical Industry Co., Ltd., trade name:
A solution obtained by adding 0.1 g of AIBN as a polymerization initiator to 8 g of light acrylate FA-108) and dissolving it was added dropwise over 1 hour. Then, polymerization was performed at 100 ° C. for 1 hour. All of the above operations were performed under a nitrogen atmosphere.

In this operation, the inside of the system was homogeneous and transparent at the initial stage of dropping, but became cloudy as the polymerization proceeded. As a result of observing the resin composition with an optical microscope, the resin composition had a structure in which fine particles of fluororesin having a particle diameter of 1 μm or less were uniformly dispersed. Also,
Even after the resin composition was allowed to stand at room temperature for one month, the particles did not settle or aggregate, and were stable.

The resin composition comprises 40 parts by weight of acrylic resin (A), 8 parts by weight of fluororesin (B) and 60 parts of solvent.
It is a system consisting of parts by weight. This resin composition is called PF-2. In Examples 5 and 6, using this resin composition PF-2, PF-2 was diluted with Hitaroid 1208C,
It was applied to a steel plate that had been subjected to bonderite treatment so that the coating film would have a thickness of 30 μm after drying, and the water repellency of the coating film was evaluated after being dried overnight at room temperature. In addition, the water repellency depends on the coating surface and # 1200.
The polished surface was evaluated. The performance is shown in Table 1.

Comparative Examples 1 and 2 Hitaloid 2411S and melan 28, which are the solvent-free acrylic paints containing no fluorine, used in the above Examples and 2.
Bake coating consisting of 9 and Hitaloid 1208C
The water repellency was evaluated on the dried coating film from The results are shown in Table 1.
It was shown to.

[0040]

[Table 1]

Claims (2)

[Claims] 1. An acrylic resin (A) containing no fluorine atom and the following general formula (1) which is substantially insoluble in the acrylic resin: (Wherein, X represents a hydrogen atom, a chlorine atom, .Y representing a fluorine atom or a methyl group or an alkylene group having 1 to 4 carbon atoms _{- (CH 2) n N (} R) SO 2 -. Represents a wherein R Represents an alkyl group having 1 to 4 carbon atoms or a hydrogen atom, and n is 1
Is an integer of ~ 4. Rf represents a C1-C15 fluoroalkyl group having a perfluoroalkyl group at the terminal. ) Fluorine-containing resin fine particles (B) having an average particle diameter of 5 μm or less and made of a fluorine-containing (meth) acrylic resin mainly containing a perfluoroalkyl group-containing polymerizable monomer unit represented by A resin composition for an acrylic water-repellent coating, which is characterized. 2. A perfluoroalkyl represented by the general formula (1) in an organic solvent in which an acrylic resin (A) containing no fluorine atom is dissolved, in the presence or absence of a dispersion stabilizer. The method for producing a resin composition for an acrylic water-repellent coating according to claim 1, wherein a monomer component containing a group-containing polymerizable monomer as a main component is polymerized in situ.