JP5928545B2 - Method for producing coating composition and method for producing coated article - Google Patents

Description

  The present invention relates to a method for producing a coating composition containing titanium dioxide particles and a coated article.

  Titanium dioxide pigments are widely used in coating compositions as white pigments that reflect visible light. The titanium dioxide pigment blocks light and imparts high durability to the coating film itself and the coated article on which the coating film is formed. On the other hand, titanium dioxide develops catalytic action by receiving light in the presence of water and oxygen, and generates hydroxyl radicals, singlet oxygen, and triplet oxygen. These are said to attack the resin and pigment and promote the deterioration of the coating film.

  For this reason, an attempt has been made to impart weather resistance by coating various inorganic compounds on the particle surface of titanium dioxide pigments used in architectural paints, automobile paints and the like that require high weather resistance.

  For example, Patent Document 1 describes a technique for obtaining a highly weather-resistant titanium dioxide pigment by using a water-soluble salt of a specific metal when forming a dense hydrous silica coating layer on the surface of titanium dioxide particles. Patent Document 2 describes a technique of a titanium dioxide pigment having an anhydrous inorganic compound coating layer containing at least dense anhydrous silica and a hydrous inorganic compound coating layer in this order on the surface of titanium dioxide particles.

  Further, Patent Document 3 and Patent Document 4 disclose a first coating layer containing cerium oxide on the surface of titanium dioxide particles as a highly weather-resistant titanium dioxide pigment, which is mainly intended for blending into a fluororesin film. And a composite particle technique in which a second coating layer containing silicon oxide is formed is described.

  However, it cannot always be said that sufficient weather resistance is imparted to the coating film obtained when these surface-coated titanium dioxide pigments are used in a coating composition. This is considered to be due to the fact that the titanium dioxide pigment present in the coating film does not have a sufficient technique for removing water, which is a causative substance of the photocatalytic reaction, from the surface of the titanium dioxide. Therefore, in a coating composition containing a titanium dioxide pigment, the coating composition is capable of preventing the entry of water to the vicinity of the titanium dioxide surface in the resulting coating film, thereby forming a coating film having high weather resistance. Things were sought.

JP 2007-9156 A JP 2008-81578 A International Publication No. 2008/078657 Pamphlet International Publication No. 2008/078704 Pamphlet

  In order to solve the above problems, the present invention provides a coating composition containing a titanium dioxide pigment, wherein the resulting coating film has a weather resistance and a coating composition having excellent weather resistance. The purpose is to provide goods.

The manufacturing method of the coating composition of this invention has the structure of the following [1]-[ 2 ]. Moreover, this invention provides the manufacturing method of the coated article which has the structure of the following [ 3 ].
[1] An aggregate of titanium dioxide particles having an average primary particle diameter of 5 μm or less having a dense surface coating layer made of at least one selected from silicon oxide, aluminum oxide, zirconium oxide and cerium oxide, and having an average secondary particle diameter A crushing step of crushing to 0.01 to 5 μm;
It possesses the mixing and dispersing step of mixing and dispersing the coating resin composed of a fluororesin the crushed titanium dioxide particles,
The crushing is performed in a state of a mixture in which the titanium dioxide particles having the surface coating layer and a part of the coating resin contained in the coating composition are mixed, and the crushing is performed in the mixing / dispersing step. The manufacturing method of the composition for coating materials which mixes a part of said resin for coating materials containing a titanium dioxide particle, and the remainder of the said resin for coating materials .

[2] The silicon oxide titanium dioxide particles having a pre-SL surface coating layer, aluminum oxide, performing the crushing against process treated with a metal oxide selected from zirconium oxide and cerium oxide, according to [1] Manufacturing method.
[3] to prepare a coating composition by the method according to [1] or [2], using the coating composition obtained by forming a coating film on the surface of an article for producing a coated article Method.

  ADVANTAGE OF THE INVENTION According to this invention, the coating composition in which the coating film obtained is excellent in a weather resistance can be manufactured in the coating composition containing a titanium dioxide pigment. Moreover, according to this invention, the coated article which has a coating film excellent in a weather resistance can be provided.

  Below, the manufacturing method of the composition for coating materials of this invention and embodiment of a coated article are demonstrated. In the present specification, the term (meth) acryl ... is used as a generic term for both acrylic ... and methacryl ...

The manufacturing method of the coating composition of this invention has the following (A) crushing process and (B) mixing and dispersion | distribution process.
(A) An aggregate of titanium dioxide particles having an average primary particle diameter of 5 μm or less having a dense surface coating layer made of at least one selected from silicon oxide, aluminum oxide, zirconium oxide and cerium oxide has an average secondary particle diameter of 0 Crushing step of crushing to 1-5 μm (B) Mixing / dispersing step of mixing and dispersing the crushed titanium dioxide particles in a resin for coating

(A) Crushing step In the step (A), titanium dioxide particles having an average primary particle diameter of 5 μm or less having a dense surface coating layer made of at least one selected from silicon oxide, aluminum oxide, zirconium oxide and cerium oxide. In this step, the aggregate is crushed so that the average secondary particle diameter is 0.1 to 5 μm. Hereinafter, titanium dioxide particles having a dense surface coating layer composed of at least one selected from silicon oxide, aluminum oxide, zirconium oxide and cerium oxide are referred to as “coated titanium dioxide”.

(Coated titanium dioxide)
The coated titanium dioxide used in the present invention is obtained by forming a dense surface coating layer made of at least one selected from silicon oxide, aluminum oxide, zirconium oxide and cerium oxide on the surface of titanium dioxide particles.

Examples of such coated titanium dioxide include titanium dioxide pigments (coated titanium dioxide) described in Patent Documents 1 to 4 mentioned above.
In the present invention, in particular, coated titanium dioxide (described in Patent Document 2) having an anhydrous inorganic compound coating layer containing at least dense anhydrous silica on the surface of titanium dioxide particles, and a hydrous inorganic compound coating layer in this order, Coated titanium dioxide (described in Patent Documents 3 and 4) in which a first coating layer containing cerium oxide and a second coating layer containing silicon oxide are formed on the surface is preferably used.

  In the anhydrous inorganic compound coating layer containing dense anhydrous silica on the surface of the titanium dioxide particles and the coated titanium dioxide having the hydrated inorganic compound coating layer, the anhydrous inorganic compound includes silicon, zirconium, titanium in addition to the dense anhydrous silica. An anhydrous oxide of at least one element selected from tin, antimony, and aluminum, an anhydride of phosphate, and the like are particularly preferable. Here, the anhydrous oxide of silicon is different from dense anhydrous silica, such as porous anhydrous silica. The anhydrous oxide other than the dense anhydrous silica and the dense anhydrous silica may be laminated on the surface of the titanium dioxide particles, or may be formed by forming a coating layer as a mixture thereof, but in the present invention, it is directly on the surface of the titanium dioxide particles. It is preferable that the anhydrous inorganic compound in contact is dense anhydrous silica.

Moreover, it is preferable that the coating amount of the anhydrous inorganic compound containing dense anhydrous silica is in the range of 2 to 15% by mass with respect to the titanium dioxide particles. Further, the coating amount of dense anhydrous silica itself is preferably in the range of 2 to 10 wt% in terms of SiO _2. When the coating amount of the dense anhydrous silica is less than the above range, desired weather resistance is difficult to obtain, and when it is more than the above range, the dispersibility of the coated titanium dioxide is reduced, and it is difficult to obtain high gloss. A more preferable range of the coating amount is 2 to 7% by mass.

The coating amounts of porous anhydrous silica, anhydrous oxides of zirconium, titanium, tin, antimony, and aluminum are respectively SiO ₂ equivalent, ZrO ₂ equivalent, TiO ₂ equivalent, SnO ₂ equivalent, Sb ₂ O _{3 with} respect to titanium dioxide particles. It is preferable to be in the range of 0.1 to 5% by mass in terms of conversion and Al ₂ O ₃ conversion. When the coating amount is less than the above range, improvement in weather resistance due to the inclusion of anhydrous oxides of these elements cannot be obtained, and when it is more than the above range, dispersibility is lowered and high gloss is hardly obtained. A more preferable coating amount is in the range of 0.5 to 3% by mass in the case of anhydrous oxides of zirconium, titanium, tin and antimony. A more preferable coating amount of the anhydrous oxide of aluminum is in the range of 0.5 to 5% by mass, and more preferably 1 to 4% by mass.

  Examples of the hydrous inorganic compound on the anhydrous inorganic compound coating layer include hydrous oxides and hydrous phosphates of at least one element selected from silicon, zirconium, titanium, tin, antimony and aluminum, Of these, hydrous oxides are preferred, and at least hydrous alumina is more preferred. The hydrous oxide and hydrous alumina of elements other than hydrous alumina may be laminated on the anhydrous inorganic compound coating layer, or may be a mixture of them formed as a mixture layer. In the present invention, the hydrous alumina is formed on the outermost layer. It is preferable to have.

The coating state of the silicon hydrated oxide is not particularly limited, and may be any of dense hydrated silica and porous hydrated silica. The coating amount of the hydrous inorganic compound is preferably 0.5 to 10% by mass in terms of anhydride. Further, the coating amount of hydrous alumina itself, preferably in the 0.5 to 5 mass% in terms _{of Al} 2 _{O 3} relative to titanium dioxide particles, more preferably 1 to 4 wt%. The coating amounts of the hydrous oxides of silicon, zirconium, titanium, tin and antimony other than hydrous alumina are the SiO ₂ equivalent, ZrO ₂ equivalent, TiO ₂ equivalent, SnO ₂ equivalent, Sb ₂ O ₃ equivalent for the titanium dioxide particles, respectively. It is preferably in the range of 0.1 to 5% by mass. When the coating amount of the hydrous inorganic compound including hydrous alumina is less than the above range, the effect of improving the dispersibility due to the inclusion of the hydrous oxide cannot be obtained. It is difficult, and the content of crystallization water is excessively increased, and the weather resistance is also lowered. A more preferable coating amount is in the range of 0.1 to 3% by mass in the case of a hydrous oxide of zirconium, titanium, tin, and antimony.

  The coated titanium dioxide having the anhydrous inorganic compound coating layer containing dense anhydrous silica on the surface of the titanium dioxide particles and the hydrous inorganic compound coating layer is formed on the hydrous inorganic compound coating layer for the purpose of improving the affinity with the organic material. Further, an organic compound is preferably deposited. Examples of such organic compounds include polyols such as trimethylolpropane, trimethylolethane, ditrimethylolpropane, trimethylolpropane ethoxylate, and pentaerythritol, monoethanolamine, monopropanolamine, diethanolamine, dipropanolamine, and triethanolamine. And alkanolamines such as tripropanolamine and derivatives thereof such as organic acid salts such as acetate, oxalate, tartrate, formate and benzoate. These may be processed one kind, may be processed two or more kinds with a mixture, or may be laminated. Among organic compounds, polyols are preferable, and trimethylolpropane and trimethylolethane are more preferable. The amount of the organic compound deposited is preferably in the range of 0.1 to 5% by mass with respect to the titanium dioxide particles, and more preferably in the range of 0.1 to 2% by mass.

  In the coated titanium dioxide in which the first coating layer containing cerium oxide and the second coating layer containing silicon oxide are formed on the surface of the titanium dioxide particles, the amount of cerium oxide contained in the first coating layer is It is preferable that it is 5-30 mass parts with respect to 100 mass parts of titanium dioxide contained in a titanium particle, and 8-20 mass parts is more preferable. Moreover, it is preferable that the quantity of the silicon oxide contained in a 2nd coating layer is 5-60 mass parts with respect to 100 mass parts of titanium dioxide contained in a titanium dioxide particle, and 10-30 mass parts is more preferable. . The first coating layer and the second coating layer may be made of cerium oxide, a composite oxide of silicon oxide and another metal oxide, respectively.

  As the titanium dioxide particles, those having an average primary particle size in the range of 0.1 to 3.0 μm are preferably used, and more preferably in the range of 0.1 to 2.0 μm. The crystal form of titanium dioxide particles supplied industrially includes an anatase type and a rutile type. In the present invention, it is preferable to use a rutile type having excellent weather resistance. The titanium dioxide particles may be obtained, for example, by a so-called sulfuric acid method in which a titanium sulfate solution is hydrolyzed or by a so-called chlorine method in which titanium halide is vapor-phase oxidized, and there is no particular limitation.

  In addition, the titanium dioxide particle used as the said core may contain substances other than a small amount of titanium dioxide. For example, it is also possible to use composite oxide particles containing titanium dioxide-coated mica or titanium dioxide.

  Examples of composite oxides containing titanium dioxide include CrSbTi oxide (orange), FeAlTi oxide (orange), NiSbTi oxide (lemon), NiCoZnTi oxide (green), and MnSbTi oxide (brown). Can be mentioned. Examples of the composite oxide pigment include yellow pigments (titanium yellow, chrome yellow, etc.), green pigments (cobalt zinc titanium, etc.), brown color pigments (manganese brown, etc.), and the like.

  Furthermore, it is also possible to use in the present invention coated titanium dioxide having particles composed of a material made of titanium dioxide doped with at least one selected from niobium, cobalt, nickel, zinc, lead, cerium and the like. As said dope amount, 0.01-5 mass% is preferable as an amount of the metal used for dope with respect to titanium dioxide.

  Here, when the coated titanium dioxide obtained by using the titanium dioxide particles doped with the metal as the core particles is used, it is blended in the coating composition to form a coating film as compared with the case of using the undoped coated titanium dioxide. In this case, the weather resistance is improved. Therefore, it is preferable to use the coated titanium dioxide using the metal-doped titanium dioxide particles depending on the required degree of weather resistance.

  The average primary particle diameter of the coated titanium dioxide used in the present invention is 5 μm or less.

  The average primary particle diameter of the titanium dioxide particles and the coated titanium dioxide is measured using a scanning electron microscope (SEM). The primary particle diameter means the particle diameter of the observed primary particles, and the average primary particle diameter means the average value of 20 particles randomly extracted from the obtained SEM image. Define with In the present invention, the average primary particle size is calculated by this method.

  In the production method of the present invention, such coated titanium dioxide can be produced according to the methods described in Patent Documents 1 to 4, but commercially available products can also be used. Specific examples of commercially available products include PFC105, CR90, CR91, CR93, CR97 (trade names, manufactured by Ishihara Sangyo Co., Ltd.), D958, D2866, D918, TCR52 (trade names, manufactured by Sakai Chemical Industry Co., Ltd.), and the like.

  Moreover, what was further processed with such metal oxides as silicon oxide, aluminum oxide, zirconium oxide, cerium oxide or the like may be subjected to the following crushing treatment as necessary.

  In the production method of the present invention, coated titanium dioxide having an average primary particle size of 5 μm or less is used. In the coated titanium dioxide, primary particles are usually aggregated to form an aggregate. The diameter of the aggregate is referred to as the secondary particle diameter, but the average secondary particle diameter is usually about 10 to 40 μm. When the coated titanium dioxide blended in the coating composition is thus aggregated to form secondary particles at the blending raw material stage, the same amount of about 10 to 40 μm is obtained even after being dispersed in the coating composition. The aggregate state is maintained at the average secondary particle diameter, and the same aggregate state is maintained even after the coating film is formed.

When the coated titanium dioxide is present in the coating film in the form of aggregates, the water that has entered the coating film enters the gaps between the coated titanium dioxide primary particles constituting the aggregate and is trapped in the titanium dioxide. It is thought to cause the action to be manifested.
Therefore, in the production method of the present invention, before blending the coated titanium dioxide into the coating composition, the aggregate is crushed to a state where water cannot enter the gaps between the primary particles.

As a method of crushing, there are usually the same methods as crushing the coated titanium dioxide aggregate, for example, crushing with a kneader, a ball mill or the like. The pulverization is performed under the condition that the average secondary particle diameter of the coated titanium dioxide aggregate is 0.01 to 5 μm, and preferably under the condition that the average secondary particle diameter is 0.01 to 3 μm. The lower limit of the average secondary particle diameter of the coated titanium dioxide aggregate obtained by crushing is not particularly limited, but the average primary particle diameter of the coated titanium dioxide can be set as the lower limit. Moreover, in this crushing process, in order to assist crushing, diluents, such as xylene, butyl acetate, and water, may be added as needed.
In addition, in this specification, the average secondary particle diameter of an aggregate means the value measured using the particle size measuring device scraper for coating materials.

  In the production method of the present invention, before the following (B) mixing / dispersing step, the free water content of the coated titanium dioxide is reduced, preferably 1% by mass or less, more preferably 0.1% by mass or less. It is preferable to perform a treatment for adjusting the free water content. The free water content of the coated titanium dioxide is calculated by measuring the following water content (mass%).

  The free water content used in the present specification is the difference (Ws−Wd) between the mass of titanium dioxide as the initial mass (Ws) and the mass of titanium dioxide after heating at 1000 ° C. for 1 hour (Wd). Is a value represented by mass% with respect to the initial mass ((Ws−Wd) × 100 / Ws). Here, “free water content” indicates water adsorbed on titanium oxide without chemical reaction, which is distinguished from crystal water.

  As a method for adjusting the free water content of the coated titanium dioxide, a baking treatment is preferable. The firing conditions are not particularly limited as long as the free water content of the obtained coated titanium dioxide is within the above range, but specifically, the treatment is preferably performed at a temperature of 300 to 900 ° C. The firing time is preferably about 30 minutes to 4 hours, although depending on the firing temperature and the type of coated titanium dioxide. In addition, the timing for firing may be before or after crushing, but when there is a possibility that the free water content is increased during crushing, it is preferably performed after crushing.

  In addition, when the coated titanium dioxide particles prepared with a low free water content are used, the coated titanium dioxide particles are blended in the coating composition compared with the case where the coated titanium dioxide with a relatively high free water content is used. The weather resistance is improved. Therefore, it is preferable to use this low free water content coated titanium dioxide according to the required degree of weather resistance.

  In the production method of the present invention, this (A) crushing step is further combined with the crushing-coated titanium dioxide in the coating composition in the following (B) mixing / dispersing step: It is preferable to carry out in the state of the mixture which mixed the covering titanium dioxide from the point which improves the dispersion state of a pigment. Here, the amount of the coating resin used in the (A) crushing step is preferably 1 to 40 parts by mass with respect to 100 parts by mass of the coated titanium dioxide to be crushed. The amount by weight is more preferred. Also in this case, a diluent such as xylene, butyl acetate, or water may be added as needed to assist crushing. Furthermore, various additive components other than a part of the coating resin contained in the coating composition may be added.

(B) Mixing / dispersing step In the (B) mixing / dispersing step in the production method of the present invention, the crushed coated titanium dioxide obtained in the step (A) is mixed and dispersed in the coating resin. Thereby, the coating composition in which the obtained coating film is excellent in weather resistance is obtained.

  Here, in the above (A) crushing step, when a part of the coating resin blended in the coating composition is used, the amount of the coating resin blended in the (B) mixing / dispersing step is originally It is the remainder obtained by subtracting the above part from the amount to be blended in the coating composition.

(Resin for paint)
As the coating resin contained in the coating composition to which the production method of the present invention is applied, a coating resin used for coating is usually not particularly limited. Examples of the coating resin include a resin made of a non-curable polymer and a resin made of a curable polymer.

  The non-curable polymer is a polymer that does not have a crosslinkable group in the polymer and does not cure by a crosslinking reaction. Examples of the non-curable polymer include a non-curable polymer having no fluorine atom and a fluorine-containing non-curable polymer having a fluorine atom. However, since the weather resistance is good, the fluorine-containing non-curable polymer is used. Coalescence is preferred.

  As the non-curable polymer having no fluorine atom, polyacrylic resins such as poly ((meth) acrylic acid ester), alkyd resins, and polyester resins are preferred, and polyacrylic resins from the viewpoint of weather resistance. Polyester resins are more preferable. Fluorine-containing non-curable polymers include polyvinylidene fluoride, vinylidene fluoride (VdF) / tetrafluoroethylene (TFE) copolymer, tetrafluoroethylene / ethylene copolymer, and chlorotrifluoroethylene (CTFE) / ethylene copolymer. Polymer, hexafluoropropylene (HFP) / tetrafluoroethylene / vinylidene fluoride copolymer, etc. are preferable, and tetrafluoroethylene / ethylene copolymer and chlorotrifluoroethylene / ethylene copolymer are more preferable from the viewpoint of adhesion. .

  Examples of commercially available products of the above polyacrylic resins include Acryloid B44 (trade name, manufactured by Rohm and Has). Commercially available products of the above-mentioned fluorine-containing non-curable polymer are all trade names of Atchem Co., Ltd., and Kyner 500, Kyner SL, Kyner ADS, and the like.

The curable polymer is a polymer having a crosslinkable group in the polymer and cured by a crosslinking reaction. Examples of the curable polymer include a curable polymer having no fluorine atom and a fluorine-containing curable polymer having a fluorine atom, but a fluorine-containing curable polymer is preferable because of good weather resistance.
Examples of the crosslinkable group that the curable polymer has include a hydroxyl group, a carboxyl group, an epoxy group, an alkoxysilyl group, a carbonyl group, an amino group, an isocyanate group, and an oxetanyl group. From the viewpoint of curability at low temperatures, A carboxyl group, an epoxy group, an alkoxysilyl group, an amino group, and an isocyanate group are preferable.

  As the curable polymer having no fluorine atom, epoxy resins, crosslinkable polyacrylic resins, alkyd resins, crosslinkable polyester resins, polyurethane resins, and silicone resins are preferred, from the viewpoint of weather resistance. Crosslinkable polyacrylic resins and crosslinkable polyester resins are more preferred.

Specific examples of the epoxy resin include bisphenol A (F) diglycidyl ether addition polymer, novolak epoxy resin, and the like.
Specific examples of the alkyd resin include medium oil alkyd resin and short oil alkyd resin.

  Specific examples of the silicone resin include dimethylpolysiloxane, epoxy-modified silicone resin, alkyd-modified silicone resin, acrylic-modified silicone resin, and polyester-modified silicone resin. Examples of commercially available silicone resins include KR271 (manufactured by Shin-Etsu Silicone), silicon ladder polymer (manufactured by Tonen), and Ceraton (manufactured by Suzuki Sangyo Co., Ltd.). An example of the acrylic-modified silicone resin is Kanekazemlac (manufactured by Kaneka Corporation). Examples of the epoxy-modified silicone resin include PSX700 (manufactured by PPGPMC Japan).

  Specific examples of the crosslinkable acrylic resin include a (meth) acrylic acid polymer having a hydroxyl group, a carboxyl group, a glycidyl group, an oxetane group, a silanol group, and an amino group. Examples of the acrylic resin include copolymers such as methacrylic acid and acrylic acid. Acrylic resin containing polyol may be used, and examples thereof include ACRIDIC A800 (manufactured by DIC) and Hitaroid (manufactured by Hitachi Chemical). Examples of the polyurethane resin include a composition obtained by blending polyisocyanate as a curing agent with these polyol resins.

Specific examples of the crosslinkable polyester resin include a polycondensation product of a dibasic acid and a polyol having a hydroxyl group, a carboxyl group, or both.
These resins may be mixed with a curing agent. As the curing agent, polyisocyanate, melamine, block polyisocyanate and the like can be used. The curing / drying temperature can be used in the range from room temperature to 300 ° C.

As the coating resin used in the present invention, a resin comprising a fluorine-containing curable polymer is most preferable because of good weather resistance. As the fluorine-containing curable polymer, a fluorine-containing copolymer having a crosslinkable group is preferable.
The fluorine-containing copolymer having a crosslinkable group (hereinafter sometimes referred to as “crosslinkable fluorine-containing copolymer”) is a copolymer having a fluorine atom and a crosslinkable group. The copolymer preferably has a polymer unit having a fluorine atom and a polymer unit having a crosslinkable group. The polymer unit having a fluorine atom is preferably a polymer unit formed by polymerizing a fluoroolefin, and the polymer unit having a crosslinkable group is a unit formed by polymerizing a monomer having a crosslinkable group. It is preferable that

  Such a crosslinkable fluorine-containing copolymer can be synthesized, for example, by polymerizing the fluoroolefin (a) and the crosslinkable functional group-containing monomer (b). It is also possible to synthesize the fluoroolefin (a) and the monomer (b) together with another alkyl group-containing monomer (c) which is further linked by an ether bond or an ester bond. preferable.

  Specific examples of the fluoroolefin (a) include chlorotrifluoroethylene (CTFE), tetrafluoroethylene (TFE), hexafluoropropylene (HFP), vinylidene fluoride (VdF), vinyl fluoride (VF), and perfluoro. Examples thereof include alkyl vinyl ether (PAVE) and a fluoroalkyl group-containing monomer. Among these, CTFE and TFE are preferable from the viewpoint of the weather resistance and solvent resistance of the coating film obtained by using this for the present invention. A fluoroolefin (a) may be used individually by 1 type, and may be used in combination of 2 or more type.

  The crosslinkable functional group-containing monomer (b) can be used without particular limitation as long as it has a crosslinkable functional group and can be copolymerized with the fluoroolefin (a). The crosslinkable functional group possessed by the monomer (b) is preferably at least one selected from the group consisting of a hydroxyl group, a carboxyl group, an amino group, an epoxy group, a silyl group, a carbonyl group, and an isocyanate group. Among these, a hydroxyl group and a carboxyl group are preferable, and a hydroxyl group is more preferable from the viewpoint of crosslinking reactivity, availability, and ease of introduction into the copolymer.

  As the crosslinkable functional group-containing monomer (b) having a hydroxyl group, specifically, 2-hydroxyethyl vinyl ether, 3-hydroxypropyl vinyl ether, 2-hydroxypropyl vinyl ether, 2-hydroxy-2-methylpropyl vinyl ether, Hydroxyalkyl vinyl ethers such as 4-hydroxybutyl vinyl ether, 4-hydroxy-2-methylbutyl vinyl ether, 5-hydroxypentyl vinyl ether, 6-hydroxyhexyl vinyl ether; diethylene glycol monovinyl ether, triethylene glycol monovinyl ether, tetraethylene glycol monovinyl ether, etc. Ethylene glycol monovinyl ethers; hydroxyethyl allyl ether, hydroxybutyl allyl ether, 2-hydroxy Hydroxyalkyl allyl ethers such as ciethyl allyl ether, 4-hydroxybutyl allyl ether and glycerol monoallyl ether; Hydroxyalkyl vinyl esters such as hydroxyethyl vinyl ester and hydroxybutyl vinyl ester; Hydroxyethyl allyl ester and hydroxybutyl allyl ester And hydroxyalkyl allyl esters such as hydroxyethyl (meth) acrylate (meth) acrylic acid hydroxyalkyl esters and the like.

  Specific examples of the crosslinkable functional group-containing monomer (b) having a carboxyl group include 3-butenoic acid, 4-pentenoic acid, 2-hexenoic acid, 3-hexenoic acid, 5-hexenoic acid, 2- Heptenoic acid, 3-heptenoic acid, 6-heptenoic acid, 3-octenoic acid, 7-octenoic acid, 2-nonenoic acid, 3-nonenoic acid, 8-nonenoic acid, 9-decenoic acid or 10-undecenoic acid, acrylic acid , Methacrylic acid, vinyl acetic acid, crotonic acid, cinnamic acid, and the like; vinyloxyvaleric acid, 3-vinyloxypropionic acid 3- (2-vinyloxybutoxycarbonyl) propionic acid, 3- (2-vinyloxy) Saturated carboxylic acid vinyl ethers such as ethoxycarbonyl) propionic acid; allyloxyvaleric acid, 3-allyloxypropionic acid, 3- (2-allyloxybutoxy) Saturated carboxylic acid allyl ethers such as carbonyl) propionic acid and 3- (2-allyloxyethoxycarbonyl) propionic acid; 3- (2-vinyloxyethoxycarbonyl) propionic acid and 3- (2-vinyloxybutoxycarbonyl) propion Carboxylic acid vinyl ethers such as acids; saturated polycarboxylic acid monovinyl esters such as monovinyl adipate, monovinyl succinate, vinyl phthalate, and vinyl pyromellitic acid; itaconic acid, maleic acid, fumaric acid, maleic anhydride, itaconic Examples thereof include unsaturated dicarboxylic acids such as acid anhydrides or intramolecular acid anhydrides thereof; unsaturated carboxylic acid monoesters such as itaconic acid monoester, maleic acid monoester, and fumaric acid monoester.

As the crosslinkable functional group-containing monomer (b) having an amino group, specifically, an amino vinyl ether represented by CH ₂ ═CH—O— (CH ₂ ) _x —NH ₂ (x = 0 to 10) _{s; CH 2 = CH-O-} CO (CH 2) allylamines represented by x -NH 2 (x = 1~10) ; other aminomethylstyrene, vinylamine, acrylamide, vinylacetamide, vinylformamide or the like.

Specific examples of the crosslinkable functional group-containing monomer (b) having an epoxy group include glycidyl vinyl ether.
As the crosslinkable functional group-containing monomer (b) having a silyl group, specifically, CH ₂ = CHCO ₂ (CH ₂ ) ₃ Si (OCH ₃ ) ₃ , CH ₂ = CHCO ₂ (CH ₂ ) _{3 Si (OC 2 H 5) 3} , CH 2 = C (CH 3) CO 2 (CH 2) 3 Si (OCH 3) 3, CH 2 = C (CH 3) CO 2 (CH 2) 3 Si (OC 2 _{H 5) 3, CH 2 =} CHCO 2 (CH 2) 3 SiCH 3 (OC 2 H 5) 2, CH 2 = C (CH 3) CO 2 (CH 2) 3 SiC 2 H 5 (OCH 3) 2, _{CH 2 = C (CH 3)} CO 2 (CH 2) 3 Si (CH 3) 2 (OC 2 H 5), CH 2 = C (CH 3) CO 2 (CH 2) 3 Si (CH 3) 2 OH CH ₂ ═CH (CH ₂ ) ₃ Si (OCOCH ₃ ) ₃ , CH ₂ ═C (CH ₃ ) CO ₂ (CH ₂ ) ₃ SiC ₂ H ₅ ( OCOCH ₃ ) ₂ , CH ₂ = C (CH ₃ ) CO ₂ (CH ₂ ) ₃ SiCH ₃ (N (CH ₃ ) COCH ₃ ) ₂ , CH ₂ = CHCO ₂ (CH ₂ ) ₃ SiCH ₃ [ON (CH ₃ ) C ₂ H ₅ ] ₂ , CH ₂ ═C (CH ₃ ) CO ₂ (CH ₂ ) ₃ SiC ₆ H ₅ [ON (CH ₃ ) C ₂ H ₂ ] ₂ and other acrylic esters or methacrylic esters CH ₂ = CHSi [ON = C (CH ₃ ) (C ₂ H ₅ )] ₃ , CH ₂ = CHSi (OCH ₃ ) ₃ , CH ₂ = CHSi (OC ₂ H ₅ ) ₃ , CH ₂ = CHSiCH ₃ ( _{OCH 3) 2, CH 2 =} CHSi (OCOCH 3) 3, CH 2 = CHSi (CH 3) 2 (OC 2 H 5), CH 2 = CHSi (CH 3) 2 SiCH 3 (OCH 3) 2, CH 2 = CHSiC ₂ H ₅ (OCOC _{3) 2, CH 2 = CHSiCH} 3 _{[ON (CH 3) C 2 H} 5 ] _2, vinyl silanes such as vinyltrichlorosilane or these partial hydrolyzates; trimethoxysilylethyl vinyl ether, triethoxysilylethyl vinyl ether, tri And vinyl ethers such as methoxysilylbutyl vinyl ether, methyldimethoxysilylethyl vinyl ether, trimethoxysilylpropyl vinyl ether, and triethoxysilylpropyl vinyl ether.

The crosslinkable functional group-containing monomer (b) may be used alone or as a monomer having different crosslinkable groups or a monomer having the same crosslinkable group but different structure. Two or more of these may be used in combination.
Moreover, a part of the hydroxyl group of the unit based on the hydroxyl group-containing monomer may be acid-modified. The acid modification is preferably carried out by allowing dicarboxylic acid or an acid anhydride of dicarboxylic acid to act on the hydroxyl group in the fluorine-containing copolymer. As the acid anhydride, succinic anhydride, phthalic anhydride, 1,2-cyclohexanedicarboxylic anhydride, and cis-4-cyclohexene-1,2-dicarboxylic anhydride are preferable.

  The acid-modified fluorine-containing copolymer and the fluorine-containing copolymer having a unit having a carboxyl group have an advantage of improving pigment dispersibility. Further, by neutralizing a part or all of the carboxyl groups with a basic compound, a water-dispersed coating material with little or no organic solvent content can be obtained.

The alkyl group-containing monomer (c) is a monomer in which an alkyl group and a polymerizable unsaturated group are linked by an ether bond or an ester bond, and the following formulas (2), (3), (4 ).
R ¹ —O—R ² (2)
R ¹ —COO—R ² (3)
R ¹ —OC (O) —R ² (4)
(R ¹ represents a linear or branched alkyl group having 2 to 20 carbon atoms not containing a quaternary carbon, and R ² represents a polymerizable unsaturated group.)

Preferred combinations of the structure of the alkyl group (R ¹ ), the linkage bond, and the structure of the polymerizable unsaturated group (R ² ) are as follows.
When the alkyl group-containing monomer (c) is an alkyl vinyl ether and the alkyl group is a linear monovalent saturated aliphatic hydrocarbon group, ethyl vinyl ether, n-propyl vinyl ether, n-butyl vinyl ether, octadecyl vinyl ether, etc. Linear monovalent saturated aliphatic alkyl vinyl ether is preferred. When the alkyl group is a branched monovalent saturated aliphatic hydrocarbon group, branched monovalent saturated aliphatic alkyl vinyl ethers such as 2-ethylhexyl vinyl ether, isopropyl vinyl ether, and isobutyl vinyl ether are preferable. In the case of a combination in which the alkyl group-containing monomer (c) is an alkyl vinyl ether, the alkyl group-containing monomer (c) is particularly preferably ethyl vinyl ether or 2-ethylhexyl ether.

  When the alkyl group-containing monomer (c) is a carboxylic acid vinyl ester and the alkyl group is a linear monovalent saturated aliphatic group, vinyl propionate, vinyl butyrate, vinyl caproate, vinyl laurate, stearic acid Linear monovalent saturated aliphatic carboxylic acid vinyl esters such as vinyl are preferred. Further, when the alkyl group is a branched monovalent saturated aliphatic hydrocarbon group, branched monovalent saturated aliphatic carboxylic acid vinyl esters such as vinyl isobutyrate and vinyl versatate are preferred.

When the alkyl group-containing monomer (c) is an alkyl allyl ether and the alkyl group is a linear monovalent saturated aliphatic hydrocarbon group, ethyl allyl ether, n-propyl allyl ether, n-butyl allyl ether, Straight chain monovalent saturated aliphatic alkyl allyl ethers such as octadecyl allyl ether are preferred. In addition, when the alkyl group is a branched monovalent saturated aliphatic hydrocarbon group, branched monovalent saturated aliphatic alkyl allyl ethers such as 2-ethylhexyl allyl ether, isopropyl allyl ether, and isobutyl allyl ether are preferable.
When the alkyl group-containing monomer (c) is an alkyl allyl ether, the alkyl group-containing monomer (c) is particularly preferably ethyl allyl ether or 2-ethylhexyl allyl ether.

  When the alkyl group-containing monomer (c) is a carboxylic acid allyl ester and the alkyl group is a linear monovalent saturated aliphatic group, allyl propionate, allyl butyrate, allyl caproate, allyl laurate, stearic acid Linear monovalent saturated aliphatic carboxylic acid allyl esters such as allyl are preferred. When the alkyl group is a branched monovalent saturated aliphatic hydrocarbon group, branched monovalent saturated aliphatic carboxylic acid allyl esters such as allyl vinylisobutyrate and allyl versatate are preferred.

Examples of the alkyl group-containing monomer (c) in which the polymerizable unsaturated group is bonded to the carbon side of the ester bond include (meth) such as ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, butyl methacrylate, isobutyl methacrylate, and cyclohexyl methacrylate. Acrylic esters are preferred.
The alkyl group-containing monomer (c) is preferably used in combination of two or more. In that case, it is particularly preferable to have at least one of ethyl vinyl ether and 2-ethylhexyl vinyl ether as an essential component.

The fluorine-containing copolymer used in the present invention may contain units based on other monomers other than (a) to (c) depending on the required properties. As the other monomer, a non-fluorine monomer is preferable, and a monomer having no crosslinkable group is preferable.
Other monomers include non-fluorinated olefins such as ethylene, propylene, n-butene and isobutene; non-fluorinated aromatic group-containing monomers such as vinyl benzoate and vinyl para-t-butylbenzoate; t-Butyl vinyl ether, vinyl pivalate and the like are preferable.

  The combination of units constituting the fluorinated copolymer is determined by the combination of monomers in producing the fluorinated copolymer, except when the structural units are reacted directly after polymerization such as acid modification. The combination of the monomers includes the fluoroolefin (a), the crosslinkable group-containing monomer (b), and the alkyl group-containing monomer (c) depending on copolymerizability, ease of production, and the crosslinking system. What is necessary is just to select suitably combining the said other monomer as an arbitrary component according to a required characteristic.

  Preferred monomer combinations include, for example, a copolymer of fluoroolefin / hydroxyalkyl vinyl ether / alkyl vinyl ether / other monomers, and a copolymer of fluoroolefin / hydroxyalkyl vinyl ether / alkyl vinyl ester / other monomers. , Copolymer of fluoroolefin / hydroxyalkyl allyl ether / alkyl allyl ether / other monomer, copolymer of fluoroolefin / hydroxyalkyl allyl ether / alkyl allyl ester / other monomer, fluoroolefin / hydroxyalkyl Allyl ether / alkyl vinyl ester / other monomer copolymer, fluoroolefin / hydroxyalkyl allyl ether / alkyl vinyl ether / other monomer copolymer Etc. are preferred.

  More specifically, for example, a copolymer of CTFE / hydroxybutyl vinyl ether / ethyl vinyl ether / other monomers, a copolymer of CTFE / hydroxybutyl vinyl ether / 2-ethylhexyl vinyl ether / other monomers, and TFE / hydroxy A copolymer of butyl vinyl ether / ethyl vinyl ether / other monomers, a copolymer of TFE / hydroxybutyl vinyl ether / 2-ethylhexyl vinyl ether / other monomers, and the like are preferable.

  When the copolymer has a hydroxyl group, a copolymer partially modified with an acid is also preferable. Moreover, the combination which does not contain the other monomer in the combination of a preferable monomer is mention | raise | lifted as a preferable combination similarly.

  The fluoroolefin (a) used in the present invention is polymerized with a crosslinkable functional group-containing monomer (b) and a monomer (c) optionally having a crosslinkable functional group other than the fluoroolefin. In the crosslinkable fluorine-containing copolymer obtained as above, the content ratio of the polymer units comprising the fluoroolefin (a) is 35 to 65 mol% in total with respect to all the polymerized units in the crosslinkable fluorine-containing copolymer. It is preferable that there is, more preferably 40 to 60 mol% in total. Sufficient weather resistance is exhibited by setting the polymerization unit composed of the fluoroolefin (a) in the crosslinkable fluorine-containing copolymer within the above range.

  In the crosslinkable fluorine-containing copolymer used in the present invention, the content ratio of the polymer units (hereinafter referred to as functional group-containing units) composed of the crosslinkable functional group-containing monomer (b) is a crosslinkable property. The total content is preferably 16 to 50 mol%, more preferably 20 to 40 mol%, based on all polymerized units in the fluorinated copolymer. If the content of the functional group-containing unit in the crosslinkable fluorine-containing copolymer is 16 mol% or more, sufficient adhesion can be secured, and if it is 50 mol% or less, gelation occurs when the copolymer is used as a solution. Hateful.

  For example, when a hydroxyl group-containing monomer is used as the crosslinkable group-containing monomer (b), the content of the unit based on the hydroxyl group-containing monomer with respect to all the units in the fluorine-containing copolymer is as follows. The amount that the hydroxyl value of the polymer is 30 to 200 mgKOH / g is preferred, and the amount that is 40 to 150 mgKOH / g is more preferred.

  In the crosslinkable fluorine-containing copolymer used in the present invention, the content ratio of the polymer units composed of the monomer (c) is 45 in total with respect to all the polymerized units in the crosslinkable fluorine-containing copolymer. It is preferably at most mol%, more preferably at most 35 mol%.

  In addition, the crosslinkable fluorine-containing copolymer used for this invention can be obtained by copolymerizing each said monomer by a conventionally well-known method. Moreover, such a crosslinkable fluorine-containing copolymer is also marketed, and a commercial item can also be used for this invention. As commercially available products of such a crosslinkable fluorine-containing copolymer, specifically, Lumiflon LF200, LF800, LF9716, FE4400, LF700F, LF710F (trade name, manufactured by Asahi Glass Co., Ltd.), Zeffle GK570, GK580, GK510, SE310, SE800 (trade name, manufactured by Daikin Industries, Ltd.), Fluonate K702, K704, K600 (trade name: manufactured by DIC), Cefral Coat TBA201 (trade name: manufactured by Central Glass Co., Ltd.), and the like.

  The curing agent that crosslinks and cures the crosslinkable fluorine-containing copolymer is appropriately selected from compounds containing functional groups having reactivity with the crosslinkable fluorine-containing copolymer depending on the type of the crosslinkable functional group. Selected. For example, when the crosslinkable fluorine-containing copolymer has a hydroxyl group as a crosslinkable functional group, an isocyanate curing agent, a melamine resin, a silicate compound, an isocyanate group-containing silane compound, and the like are preferable. Moreover, when a crosslinkable fluorine-containing copolymer contains a carboxyl group as a crosslinkable functional group, an amino-type hardener and an epoxy-type hardener are mentioned preferably. Furthermore, when the crosslinkable fluorine-containing copolymer contains an amino group as a crosslinkable functional group, a carbonyl group-containing curing agent, an epoxy curing agent, or an acid anhydride curing agent is usually employed.

  As for such a curing agent, commercially available products such as Coronate HX (trade name, manufactured by Nippon Polyurethane Co., Ltd.), Bihijoule XP7063 (trade name, manufactured by Bayer), Vestagon B1530 (trade name, Evonik Degussa) Can be used.

  The amount of the curing agent to be used is such that the functional group amount of the curing agent is 0.6 to 1.5 mol with respect to 1 mol of the crosslinking functional group of the crosslinkable fluorine-containing copolymer. The amount is preferred, more preferably 0.7 to 1.4 mol.

As mentioned above, although the crosslinkable fluorine-containing copolymer and the curing agent that are preferably used as the coating resin in the present invention have been described, the coating resin may be used alone or in combination of two or more. Good.
Furthermore, the coating composition contains additives such as a film-forming aid, a surface conditioner, a thickener, a UV absorber, a light stabilizer, and an antifoaming agent in addition to the coating resin and the crushed coated titanium dioxide. You may contain suitably. Moreover, it is also possible to mix | blend coloring materials, such as a matting agent and organic pigments other than the said disintegrated coating titanium dioxide, an inorganic pigment, according to a use.

  In the production method of the present invention, in the step (B), these compounding components are mixed by a usual method, for example, a disper or the like, and a coating composition in which the crushed coated titanium dioxide is dispersed in the composition is obtained. . The blending amount of the crushed coated titanium dioxide can be generally the same as the blending amount of the coated titanium dioxide in the coating composition. Specifically, it is preferable to blend at a ratio of 0.5 to 5% by mass with respect to the total amount of the composition.

  The form of the coating composition obtained by the production method of the present invention may be any of a solvent form, a weak solvent system, a water solubility, an aqueous dispersion, a non-aqueous dispersion, an ionic system (electrodeposition), and a powder form. There may be. According to various forms to be produced, the crushed coated titanium dioxide and paint resin and other various blending components are blended and mixed by a usual method to form a desired composition for the paint. It can be.

  According to the manufacturing method of the coating composition of the present invention described above, the coating material according to this manufacturing method is configured so that the causative substance water is not guided near the surface of the coated titanium dioxide when the coating film is formed. The weather resistance of the coating film obtained by using the composition for the use is improved.

In this invention, the coating article in which the coating film was formed using the coating composition obtained in the manufacturing method of the said coating composition is contained.
The present coated article can be obtained by coating the article to be coated by a conventionally known method suitable for the type of coating resin contained in the coating composition and the various forms produced above.

  Examples of the coated article of the present invention include a coated article that is generally used after being coated with a paint containing a titanium dioxide pigment. Since the coating film obtained by using the coating composition according to the production method of the present invention is excellent in weather resistance, the effect can be exerted particularly when used for a coated article requiring a high degree of weather resistance. Specific examples of such coated articles include solar cell module back sheets, wind power generator blades / towers / transformers, solar thermal power generation mirrors, communication towers, power transmission towers, bridges, marine structures, sashes , Curtain walls, building materials and the like.

  The present invention will be described below based on examples, but the present invention is not limited to these examples. In addition, the following moisture remaining means a free moisture content (mass%). The particle size refers to the average aggregate particle size = average secondary particle size measured with a scraper / ground gauge (manufactured by Toyo Seiki) (hereinafter simply referred to as “scraper”). Moreover, about the various commercial items used for the Example and the comparative example, it was as follows, and it was set as description of only the brand name in each example.

(Coated titanium dioxide particles)
PFC105: Average primary particle size 0.28 μm, manufactured by Ishihara Sangyo Co., Ltd. D958: Average primary particle size 0.25 μm, manufactured by Sakai Chemical Industry Co., Ltd.

(Resin for paint)
Lumiflon LF200: Crosslinkable fluorine-containing copolymer, manufactured by Asahi Glass Co., Ltd. Lumiflon FE4400: Crosslinkable fluorine-containing copolymer, manufactured by Asahi Glass Co., Ltd. Acryloid B44: Polyacrylic resin, manufactured by Rohm and Hass Co., Ltd.

(Curing agent)
Coronate HX: Polyisocyanate compound, manufactured by Nippon Polyurethane Co., Ltd. Bihijoule XP7063: Polyisocyanate compound, manufactured by Bayer

[Example 1]
100 g of PFC105 was prepared as titanium dioxide, and it was confirmed that the remaining amount of water was 1.5% by mass. 40 g of Lumiflon LF200 and 100 g of xylene were blended with 100 g of this PFC105, and 100 g of 2 mmφ glass beads were used for stirring and dispersing treatment for 2 hours with a paint shaker. The glass beads were removed by filtration, and it was confirmed with a scraper that the particle size was 5 μm or less. Further, 126.6 g of Lumiflon LF200 was further added and blended, and 9.2 g of Coronate HX was blended as a curing agent to obtain a coating composition.

  The obtained coating composition was applied to a PET film with a bar coater so that the film thickness after drying was 15 μm, and dried and cured at 120 ° C. for 5 minutes. Next, this coated PET film was mounted with the coated surface as the back sheet of the solar cell module facing outside.

[Example 2]
After preparing 100 g of titanium dioxide D958 and confirming that the remaining amount of water is 1.2% by mass, mix 50 g of water with this and stir for 2 hours with a paint shaker using 100 g of 2 mmφ glass beads.・ Distributed processing. The glass beads were removed by filtration, and it was confirmed with a scraper that the particle size was 5 μm or less. Furthermore, 200 g of fluorine emulsion Lumiflon FE4400 was further blended, and 10 g of Bihijoule XP7063 was blended as a curing agent to obtain a coating composition.
The obtained coating composition was applied to the wind power blade by spraying and dried and cured at room temperature for 3 days to form a coating film.

[Comparative Example 1]
After preparing 100 g of PFC105 as titanium dioxide and confirming that the remaining amount of water is 1.5% by mass, 40 g of Lumiflon LF200 and 100 g of xylene are blended in this, and a paint shaker using 100 g of 2 mmφ glass beads. The mixture was stirred and dispersed for 1.5 hours. The glass beads were removed by filtration, and it was confirmed with a scraper that the particle size was 15 μm or less. Furthermore, 126.6g of Lumiflon LF200 was further added and blended, and 9.2g of Coronate HX was blended as a curing agent to obtain a coating composition.

  The obtained coating composition was applied to a PET film with a bar coater so that the film thickness after drying was 15 μm, and dried and cured at 120 ° C. for 5 minutes. Next, this coated PET film was mounted with the coated surface as the back sheet of the solar cell module facing outside.

The following tests were conducted on the coating compositions prepared in the above Examples and Comparative Examples to evaluate the weather resistance.
[Accelerated weather resistance test]
In the xenon weather meter test indicated by ISO 11341 (2004), the test was carried out by changing the water spray to a 0.2 mass% hydrogen peroxide spray for 2 minutes. This test was developed as a measure of the degree of photocatalytic activity of a coating obtained from a coating composition containing titanium dioxide particles. In the accelerated test, the coating compositions obtained in Examples and Comparative Examples were coated on a 0.8 mm-thick aluminum allodine-treated plate with a film thickness of 25 μm to obtain a test piece. The evaluation was as follows based on a chalking rate of 2 or less as shown in JIS 5600 for a gloss retention of 80%.

○: Maintain over 600 hours.
(Triangle | delta): It maintains over 400 hours and falls below in 600 hours.
X: Less than 200 hours.

The results are shown in Table 1 together with a list of production methods of each example and comparative example.

[Example 3]
Using 50g of PFC105 and 50g of D958 as a total of 100g as titanium dioxide, 30g of Acryloid B44 and 100g of MEK (methyl ethyl ketone) are added to this, and stirring and dispersion treatment for 2 hours with a paint shaker using 100g of 2mmφ glass beads. Went. The glass beads were removed by filtration, and it was confirmed with a scraper that the particle size was 5 μm or less. Further, 70 g of Kyner 500 resin (manufactured by Atchem) and 120 g of MEK were added and blended to prepare a coating composition.

  The coating composition obtained above was coated on an aluminum anodized sash coated with an epoxy resin primer so that the film thickness after drying was 20 μm, and dried at 270 ° C. for 30 seconds. In addition, when the said accelerated weathering test was done about the obtained composition for coating materials, the result was a pass "(circle)".

  By using the coating composition according to the production method of the present invention, it is possible to form a coating film containing a titanium dioxide pigment having excellent weather resistance, and a primer or a metal or plastic such as a steel plate or surface-treated steel plate, or a raw material such as an inorganic material. Useful as an overcoat. In particular, solar cell module backsheets, wind power generator blades / towers / transformers, solar power generation mirrors, communication towers, power transmission towers, bridges, offshore structures, sashes, curtains that require high weather resistance Useful for walls and building materials.

Claims (3)

An aggregate of titanium dioxide particles having an average primary particle diameter of 5 μm or less having a dense surface coating layer made of at least one selected from silicon oxide, aluminum oxide, zirconium oxide and cerium oxide has an average secondary particle diameter of 0.01. A crushing step of crushing to be ~ 5 μm;
It possesses the mixing and dispersing step of mixing and dispersing the coating resin composed of a fluororesin the crushed titanium dioxide particles,
The crushing is performed in a state of a mixture in which the titanium dioxide particles having the surface coating layer and a part of the coating resin contained in the coating composition are mixed, and the crushing is performed in the mixing / dispersing step. The manufacturing method of the composition for coating materials which mixes a part of said resin for coating materials containing a titanium dioxide particle, and the remainder of the said resin for coating materials. Silicon oxide titanium dioxide particles having a pre-SL surface coating layer, aluminum oxide, performing the crushing against process treated with a metal oxide selected from zirconium oxide and cerium oxide, the production method according to claim 1 . How to prepare a coating composition, by using the coating composition obtained by forming a coating film on the surface of an article for producing a coated article by the method according to claim 1 or 2.