JP7635919B2 - UV absorber aqueous composition - Google Patents

Description

The present invention relates to an ultraviolet absorbent composition, a method for producing the same, and a method for producing a coating composition.

Benzotriazole-based ultraviolet absorbers have been widely used due to their excellent ultraviolet absorbing properties, photostability, etc. In particular, 2,2'-methylenebis[6-(2H-benzotriazol-2-yl)-4-tert-octylphenol] (also known as bisoctrizole) is known as an ultraviolet absorber capable of absorbing long wavelengths, but it is an organic compound and is generally used in a molecular state by dissolving it in a volatile organic solvent or the like.
However, because of concerns about the effects of volatile organic solvents on the environment and human body, the use of aqueous solvents is desirable, but bisoctrizole is insoluble in water, so methods for dispersing the compound in water have been reported (Patent Documents 1, 2, 3, 4, and 5).
By dispersing in water, not only can an aqueous solvent be used and no organic solvent is required, but since it is in a dispersed state and not dissolved, the light resistance of the UV absorber itself is improved, and since the dispersed state has increased absorption up to longer wavelengths than the dissolved state, the amount of UV absorber used can be reduced, so that it is expected that the range of applicable products will be expanded to include water-based paints, sol-gel coating liquids, in-line coating liquids, etc. Furthermore, by making it into an aqueous dispersion, it can be processed into a paint form or a film form, and in particular, by making it into a transparent dispersion, it is expected that it will be widely applied to products that require light resistance and transparency, such as fiber materials, inks, cosmetics, etc.

JP 2017-95559 A Patent No. 5270134 WO2015/152057 Patent No. 5396265 Patent No. 5700552

However, the inventor's investigations have revealed that it is difficult to improve visible light transmittance while sufficiently blocking ultraviolet light with the dispersions disclosed in these previously known documents. Specifically, among the above documents, Patent Documents 1 to 3 do not provide a visible light (600 nm) transmittance of more than 25% (values when the ultraviolet absorber concentration is 0.00982%) when the transmittance in the ultraviolet region (200 nm to 380 nm) is 0.0%. For this reason, it is difficult to apply these to applications that require higher transparency than those reported above, such as glass coating.

Furthermore, in Patent Documents 4 and 5, high transmittance is maintained by undergoing a long manufacturing process, and the long manufacturing process does not result in high production efficiency.
Therefore, there has been a demand for a dispersion composition that can be produced efficiently in a short production process while maintaining high transmittance.

The inventors have conducted extensive research to solve the above problems. As a result, they have found that by using a specific UV absorber and dispersing it with a surfactant, it is possible to improve the transmittance in a shorter time than ever before. In other words, the dispersion is a dispersion in which a specific bis-octrizole-related compound is dispersed in water, and the dispersion contains a surfactant.

式中、
R₁及びR_1'は、互いに同一又は異なってもよく、水素原子、ハロゲン原子、ニトロ基、シアノ基、１個ないし１２個の炭素原子を有するペルフルオロアルキル基、R₃ＳＯ－基又はR₃Ｏ₂－基である。
R₂及びR_2'は、互いに同一又は異なってもよく、炭素原子数１～１２のアルキル基、CO₂H基により置換された炭素原子数１～１２のアルキル基、フェニル基、アルキル基部分に１～４個の炭素原子を含むフェニルアルキル基、または炭素原子数５～８のシクロアルキル基である。
R₃は炭素原子数１ないし２０のアルキル基、炭素原子数２ないし２０のヒドロキシアルキル基、炭素原子数２ないし９のアルコキシカルボニル基により置換されたアルキル基、炭素原子数３ないし１８のアルケニル基、炭素原子数５ないし１２のシクロアルキル基、炭素原子数７ないし１５のフェニルアルキル基、炭素原子数６ないし１０のアリール基又は炭素原子数１ないし４のアルキル基１個又は２個により置換された前記アリール基、或いは１，１，２，２－テトラヒドロペルフルオロアルキル基（この基のペルフルオロアルキル部分は、６個ないし１６個の炭素原子からなる）である。
（２） 紫外線吸収剤が、平均分散粒子径１０～３５ｎｍで分散していることを特徴とする上記（１）記載の紫外線吸収剤水性組成物、 That is, the present invention provides
(1) An aqueous composition containing at least an ultraviolet absorbent and a dispersant in an aqueous medium, the ultraviolet absorbent being a compound represented by the following general formula (I), and containing a surfactant;

General formula (I)

In the formula,
R ₁ and R _1' may be the same or different and each is a hydrogen atom, a halogen atom, a nitro group, a cyano group, a perfluoroalkyl group having 1 to 12 carbon atoms, an R ₃ SO-- group or an R ₃ O ₂ -- group.
_R2 and R2 _' may be the same or different and are an alkyl group having 1 to 12 carbon atoms, an alkyl group having 1 to 12 carbon atoms substituted with a _CO2H group, a phenyl group, a phenylalkyl group containing 1 to 4 carbon atoms in the alkyl moiety, or a cycloalkyl group having 5 to 8 carbon atoms.
_R3 is an alkyl group having 1 to 20 carbon atoms, a hydroxyalkyl group having 2 to 20 carbon atoms, an alkyl group substituted by an alkoxycarbonyl group having 2 to 9 carbon atoms, an alkenyl group having 3 to 18 carbon atoms, a cycloalkyl group having 5 to 12 carbon atoms, a phenylalkyl group having 7 to 15 carbon atoms, an aryl group having 6 to 10 carbon atoms, or the above aryl group substituted by one or two alkyl groups having 1 to 4 carbon atoms, or a 1,1,2,2-tetrahydroperfluoroalkyl group (the perfluoroalkyl portion of this group consists of 6 to 16 carbon atoms).
(2) The aqueous ultraviolet absorbent composition according to (1) above, wherein the ultraviolet absorbent is dispersed with an average dispersed particle size of 10 to 35 nm.

(3) The aqueous ultraviolet absorbent composition according to the above (1)-1 or (2), wherein the dispersant is one or more compounds selected from acrylic copolymers of control polymerization.
(4) In the compound of the general formula (I),
The aqueous ultraviolet absorbent composition according to any one of (1) to (4) above, wherein R ₁ is chlorine and R ₂ is tert-octyl.
(5) A method for producing a coating composition, comprising mixing the aqueous ultraviolet absorbent composition according to any one of (1) to (4) above with a resin component to prepare a coating liquid.
is located.

The present invention makes it possible to obtain an ultraviolet absorbent composition that can sufficiently block ultraviolet rays while improving visible light transmittance, and a coating composition using the same.

FIG. 1 is a graph showing the transmittance versus wavelength of the ultraviolet absorbent dispersions of the present invention obtained in Examples 1 and 4 and the ultraviolet absorbent dispersions obtained in Comparative Examples 3 and 7. FIG. 2 is a graph showing absorbance versus wavelength for the ultraviolet absorbent dispersions of the present invention obtained in Examples 1 and 4 and the ultraviolet absorbent dispersions obtained in Comparative Examples 3 and 7.

The present invention will be described in detail below.
[UV absorbing compounds]
1. Structure of UV-Absorbing Compound In the present invention, a UV-absorbing compound represented by the following general formula (1) is used.

General formula (1)

In the formula,
R ₁ and R _1' may be the same or different and each is a hydrogen atom, a halogen atom, a nitro group, a cyano group, a perfluoroalkyl group having 1 to 12 carbon atoms, an R ₃ SO-- group or an R ₃ O ₂ -- group.

_R2 and R2 _' may be the same or different and are an alkyl group having 1 to 12 carbon atoms, an alkyl group having 1 to 12 carbon atoms substituted with a _CO2H group, a phenyl group, a phenylalkyl group containing 1 to 4 carbon atoms in the alkyl moiety, or a cycloalkyl group having 5 to 8 carbon atoms, preferably an alkyl group having 1 to 12 carbon atoms.

_R3 is an alkyl group having 1 to 20 carbon atoms, a hydroxyalkyl group having 2 to 20 carbon atoms, an alkyl group substituted by an alkoxycarbonyl group having 2 to 9 carbon atoms, an alkenyl group having 3 to 18 carbon atoms, a cycloalkyl group having 5 to 12 carbon atoms, a phenylalkyl group having 7 to 15 carbon atoms, an aryl group having 6 to 10 carbon atoms, or the above aryl group substituted by one or two alkyl groups having 1 to 4 carbon atoms, or a 1,1,2,2-tetrahydroperfluoroalkyl group (the perfluoroalkyl portion of this group consists of 6 to 16 carbon atoms).
R ₁ and R _1' are preferably a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a halogen group.
More preferably, it is a hydrogen atom or a halogen group.
Most preferably, it is a chlorine atom.

_R2 and R2 _' are preferably alkyl groups having 1 to 12 carbon atoms.
Most preferably, both R ₂ and R _2′ are the following groups:

These compounds are known and commercially available products can be used, or they can be produced by various known methods for producing benzotriazole compounds. Generally, benzotriazole compounds are produced from phenols as raw materials, and then the benzotriazole is dimerized with aldehydes. For example, they can be produced by the methods described in Japanese Patent 3223377 and German Patent 1,670,951.

2. Glass transition point of ultraviolet absorbing compound The ultraviolet absorbing compound used in the present invention preferably has a glass transition point of 35° C. or higher, more preferably 60° C. or higher, and most preferably 67° C. If the glass transition point is too low, the glass transition point is exceeded due to the heat of dispersion during dispersion, and crystallinity cannot be maintained, making it difficult to proceed with dispersion. This results in an increase in particle size and a decrease in transparency.

3. Melting Point of Ultraviolet Absorbing Compound The ultraviolet absorbing compound used in the present invention preferably has a melting point of 150° C. or higher, more preferably 190° C. or higher, and most preferably 205° C. or higher. If the melting point is too low, the glass transition point also tends to be low, resulting in the above-mentioned problems.

The melting point and glass transition point were measured by DSC. More specifically, they were measured according to the method described in JIS standard K-7121-1987 "Method for measuring transition temperature of plastics."

Molecular Weight of UV Absorber The UV absorbing compound used in the present invention preferably has a molecular weight of 400 to 2500, more preferably 650 to 750, and most preferably 727.76. If the molecular weight is lower than 400, the melting point and glass transition point tend to be low, and if it is higher than 2500, the compound tends to be difficult to crystallize, causing a problem that it cannot be dispersed.

[Surfactant]
In the present invention, a surfactant is contained.
The surfactant can be, for example, ionic surfactant, nonionic surfactant and cationic surfactant.The ionic surfactant can be, for example, fatty acid salt, alkyl sulfate ester salt, alkyl benzene sulfonate salt, alkyl naphthalene sulfonate salt, alkyl sulfosuccinate salt, alkyl diphenyl ether disulfonate salt, polyoxyethylene alkyl sulfate ester salt, polyoxyethylene alkyl aryl sulfate ester salt, alkane sulfonate salt, naphthalene sulfonate formalin condensate, polyoxyethylene alkyl phosphate ester salt, N-methyl-oleoyl taurate salt, α-olefin sulfonate salt. Examples of nonionic surfactants include polyoxyethylene alkyl ethers, polyoxyethylene alkylaryl ethers, polyoxyethylene derivatives, ethylene oxide-propylene oxide block copolymers, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene sorbitol fatty acid esters, glycerin fatty acid esters, polyoxyethylene fatty acid esters, polyoxyethylene alkylamines, acetylene glycols, and ethylene glycol adducts of acetylene glycols. Examples of cationic surfactants and amphoteric surfactants include alkylamine salts, quaternary ammonium salts, alkyl betaines, and amine oxides. These ionic surfactants may be used as dispersants, wetting agents, detergents, and surface tension adjusters, which will be described later.

Particularly preferred surfactants are polyoxyalkylene derivatives having an HLB of 9 to 16, preferably 11 to 15, and most preferably 13.2, having 1 to 3 benzyl groups which may be bonded to any part of the phenyl ether ring, and the hydrophilic group may contain ethylene oxide or propylene oxide, and the ethylene oxide or propylene oxide may contain -SO ₃ NH ₄ , -PO ₃ H ₂ or other ionic group at the terminal.

Commercially available products include Kao's Emulgen A-60, Emulgen A-90, and Emulgen B-66, Toho Chemical's TS1500, TS2000, and TS2600, Clariant's Emulsogen TS160, and Dispersing agent LFH, LFES, Nippon Nyukazai's Newcoal 704, 706, 707, 708, 709, 710, 711, 712, 714, 714(80), 719, 610, 610(80), 2604, 2607, 2609, 2614, 707-F, 710-F, 714-F, 2608-F, 2600-FB, 2616-F, 3612-FA, 707-SF, 707-SFC, 707-SN, 714-SF, 714-SN, 723-SF, 740-SF, 780-SF, 2 607-SF, 2614-SF, Takemoto Oil's New Calgen C-150, C-173, C-200, C-314, CP-50, CP-80, CP-120, CP-15-200, Paionin D-6112, D-6512, D-6414, DTD-51, Miyoshi Oil's Trimin CB#32, Daiichi Kogyo Seiyaku's Hitenol NF-13, Plysurf AL, Noigen EA-87, EA-137, EA-157, EA-167, EA-177 can be used. Most preferably, Emulgen B66.

[Polymer Dispersant]
In addition to the above surfactants, a polymer dispersant may be used in combination. A preferred polymer dispersant is an acrylic copolymer obtained by control polymerization.
Commercially available products include Disperbyk-190, 2010, 2012, 2013, 2015, 2055, 2060, 2061, and 2096 manufactured by BYK-Chemie. Disperbyk-190 and 2015 are preferred, and Disperbyk-2015 is most preferred, as they have high compatibility with the surfactant used in combination and improve dispersibility compared to the case of using the surfactant alone.

[Dispersion medium]
In the present invention, at least the above components are dispersed in water. If a dispersion medium other than water is contained, the ultraviolet absorber will dissolve, which may cause a problem of wavelength shift to shorter wavelengths, so it is preferable to contain as little dispersion medium other than water as possible. It is desirable to suppress the amount of dispersion medium other than water to 1% by weight or less in the dispersion liquid, and preferably the dispersion medium is 100% water.

[Content of each ingredient]
The content of the ultraviolet absorber in the dispersion is preferably 5 to 20% by mass. If it is less than 5%, the shear is not applied and the dispersion does not proceed easily, and if it exceeds 20% by mass, the viscosity becomes high and the dispersion does not proceed easily. It is preferably 8 to 12% by mass, and most preferably 10% by mass.
The content of the surfactant is preferably 1 to 100 parts by mass relative to 100 parts by mass of the ultraviolet absorber. If the content of this surfactant is less than 1 part by mass, it becomes difficult to crush the particles to 50 nm or less, and there are problems such as a long dispersion time. If the content of the surfactant exceeds 100 parts by mass, the viscosity becomes high and dispersion becomes difficult to proceed. It is preferably 50 to 90 parts by mass, and most preferably 70 parts by mass.

When a polymer dispersant is used in combination with a surfactant, it is preferable to use 1 to 100 parts by weight per 100 parts by weight of UV absorber, within the above surfactant content range. If the amount is less than 1 part by weight, the effect of the combination is small, and if the amount exceeds 100 parts by weight, the viscosity increases and dispersion becomes difficult to proceed. It is preferably 5 to 20 parts by weight, and most preferably 10 parts by weight.

[Production of UV absorber dispersion]
The ultraviolet absorbent dispersion of the present invention can be produced using, for example, a media-type disperser or a collision-type disperser. A media-type disperser is a disperser that disperses by moving small-diameter media such as glass, alumina, zirconia, steel, tungsten, etc., at high speed in a vessel and grinding the slurry passing between them with the shear force between the media. Specific examples of the media-type disperser include a ball mill, a sand mill, a pearl mill, a spike mill, an agitator mill, a cobo mill, and an ultravisco mill.

The collision type disperser is a disperser that disperses by crushing pigments and the like in a fluid by colliding a fluid against one wall at high speed or by colliding fluids with each other at high speed. Examples of collision type dispersers include a jet mill that accelerates and crushes raw material particles using a high-speed jet stream, and "Starburst" (registered trademark, manufactured by Sugino Machine Co., Ltd.), which is a wet-type micronization device. Other known dispersing devices, such as a roll mill and an ultrasonic disperser, may also be used for production. Of the various dispersing devices described above, any device and media that can provide sufficient shear force to obtain the desired particle size may be used, and generally, various media-type dispersers are suitable. These devices and media are appropriately selected, the above-mentioned components are added, and the ultraviolet absorbing compound is processed until it becomes fine particles having the above-mentioned desired particle size.

[Physical Properties of UV Absorber Dispersion]
1. Transparency The ultraviolet absorber dispersion of the present invention can be a composition having excellent transparency while maintaining sufficient ultraviolet absorbing performance. This can be confirmed by the following two indexes.
First, the ultraviolet absorber dispersion is diluted with water so that the ultraviolet absorber concentration becomes 0.0982%, and the transmission spectrum is measured at room temperature using a ultraviolet-visible spectrophotometer (Shimadzu Corporation, UV-1850) to confirm the transmittance at 600 nm.

In this case, the composition of the present invention can achieve a transmittance of 75% or more at 600 nm.
Furthermore, it can be 85% or more, and further it can be 93% or more.
In this case, a dispersion with a content lower than 75% will become cloudy and have a low transparency, but as shown in the comparative example described below, it is difficult to achieve a content of 75% or more using conventional techniques.

Next, the ultraviolet absorber dispersion of the present invention is diluted with water so that the ultraviolet absorber concentration becomes 0.002%, and the absorption spectrum is measured at room temperature using a ultraviolet-visible spectrophotometer (Shimadzu Corporation, UV-1850).
In this case, the absorbance at 380 nm (A380) can be set to 0.50 to 0.70.
In addition, A380/A600, which is the ratio of the absorbance at 380 nm (A380) to the absorbance at 600 nm (A600) of the absorption spectrum, can be 200 or more, or can be 250 or more, or can be 600 or more, or can be 650.
A high A380/A600 value means that the material can transmit enough of the visible light range while absorbing enough of the ultraviolet range. If the A380/A600 value is lower than 200, it becomes difficult to maintain high transparency while sufficiently blocking the ultraviolet range.
The relationship between wavelength and transmittance of the ultraviolet absorbent dispersion of the present invention is shown in Figure 1, and the relationship between wavelength and absorbance is shown in Figure 2. As can be seen from these figures, the ultraviolet absorbent dispersion of the present invention has high transmittance in the defective region, is excellent in transparency, and maintains high transparency while sufficiently blocking the ultraviolet region.

2. Dispersed Particle Size In the dispersion of the present invention, the particle size of the ultraviolet absorbing compound is preferably adjusted to fall within a certain range.
Specifically, when the ultraviolet absorber concentration of the ultraviolet absorber dispersion of the present invention is diluted with water so that the loading index is in the range of 0.1 to 100, and the particle diameter is measured at room temperature using a particle size distribution measuring device (Microtrac UPA EX-150, manufactured by Nikkiso Co., Ltd.), the particle diameter is 10 to 35 nm, preferably 10 to 30 nm, and most preferably 13 to 20 nm. Within this range, the balance between the ultraviolet absorbing performance and the transparency described above is the best.
If the particle size is larger than 35 nm, the transparency tends to decrease, whereas if the particle size is smaller than 10 nm, the liquid stability over time tends to decrease, and the ultraviolet absorbing performance tends to decrease.

The viscosity of the ultraviolet absorber dispersion of the present invention, measured at 25° C. using a viscometer (manufactured by Toki Sangyo Co., Ltd., product number “VISCOMETER TV-22”), is preferably 2.0 to 4.5 mPa·s, particularly preferably 2.0 to 3.0 mPa·s.
This range is particularly preferred because it is easy to mix with other materials such as resin components and is easy to handle.
By mixing the above-mentioned components in the above-mentioned ratios, the viscosity can be easily adjusted to a preferred range.

4. pH
The pH of the ultraviolet absorber dispersion of the present invention can be appropriately selected depending on the purpose and the relationship with the pH of other components such as the resin to be blended. The pH can be appropriately adjusted by selecting the functional group of the surfactant.

The aqueous ultraviolet absorbent composition described above can be further mixed with a resin component to form a coating liquid, thereby forming a coating composition.
Here, the coating composition of the present invention is a composition capable of forming a coating film on a substrate. For example, it can be used for various applications such as those described in WO2015/152057.

The coating composition of the present invention contains a highly functional ultraviolet absorber in the coating that is formed, and therefore can reduce damage from sunlight or ultraviolet light in the coating itself that is formed, in a substrate that is coated with the coating, and in a material that is exposed to sunlight or ultraviolet light through the coated substrate (coated article).

The substrate to be coated with the coating composition of the present invention is not limited, and examples thereof include glass, resin glass, metal, plastic, fiber, cloth, paper, wood, concrete, etc. These substrates may be, for example, window glass components, interior and exterior materials, building materials such as architectural structures, containers for food, medicines, cosmetics, chemicals, etc., signs, labels, solar cells, etc. In addition, by using the coating composition of the present invention as a substrate for a printed matter, it is possible to prevent the ink from fading. The coating composition of the present invention may be an ink, and in this case, for example, it is possible to prevent the ink from fading. The coating composition of the present invention may be an adhesive, and in this case, it is possible to prevent the adhesive from deteriorating due to sunlight or ultraviolet rays. Furthermore, it is also possible to produce, for example, clothing, hats, umbrellas, etc., having an ultraviolet ray shielding effect by coating a substrate such as a fiber with the coating composition of the present invention.

The present invention will now be described more specifically with reference to examples.
Example 1
10.0 parts by weight of compound 1 (2,2'-methylenebis[6-(5-chloro-2H _- benzotriazol-2-yl)-4-tert-octylphenol]) in which both R ₁ and R ₁ ' in general formula (I) are chlorine atoms and both R 2 and R _2' are 1,1,3,3-tetramethylbutyl groups, 7.0 parts by weight of polyoxyethylene tribenzyl phenyl ether ("EMULGEN B-66", manufactured by Kao Corporation, HLB 13.2) as a surfactant, and 83.0 parts by weight of water were mixed and ground in a paint conditioner using zirconia beads having a diameter of 0.1 mm for 10 hours, to obtain ultraviolet absorber dispersion 1.
The average particle size of the fine particles of the ultraviolet absorber in the obtained dispersion was measured at room temperature using a particle size distribution measuring device (Microtrac, manufactured by Nikkiso Co., Ltd.) and was found to be 28 nm (median size, D ₅₀ ).
The obtained ultraviolet absorber dispersion 1 was diluted with water so that the ultraviolet absorber concentration was 0.0982%, and the transmission spectrum was measured at room temperature using an ultraviolet-visible spectrophotometer (Shimadzu Corporation, UV-1850). As a result, the transmittance at 600 nm was 86.9%.

Example 2
The ultraviolet absorber was dispersed in the same manner as in Example 1, except that the surfactant used was 7.0 parts by weight of polyoxyethylene tribenzyl phenyl ether ("EMULGEN B-6" manufactured by Kao Corporation, HLB 13.2), the dispersant used was 2.5 parts by weight of a polymer dispersant having an acid value (disperbyk-2015 manufactured by BYK-Chemie, acid value 10 mg KOH/g, active ingredient 40.0 wt%), and the water was 80.5 parts by weight.
The average particle size and transmittance of the ultraviolet absorber in the obtained dispersion were measured in the same manner as in Example 1, and were found to be 15 nm and 93.2%, respectively.

Example 3
The ultraviolet absorber was dispersed in the same manner as in Example 1, except that the surfactant used was 1.0 part by weight of polyoxyethylene tribenzyl phenyl ether ("EMULGEN B-66" manufactured by Kao Corporation, HLB 13.2), the dispersant used was 17.5 parts by weight of a polymer dispersant having an acid value ("disperbyk-2015" manufactured by BYK-Chemie, acid value 10 mg KOH/g, active ingredient 40.0% by mass), and the water was 71.5 parts by weight.
The average particle size and transmittance of the ultraviolet absorber in the obtained dispersion were measured in the same manner as in Example 1, and were found to be 31 nm and 80.4%, respectively.

Example 4
An ultraviolet absorbent was dispersed in the same manner _as in Example ₁ , except that the ultraviolet absorbent was changed to compound 2 (2,2'-methylenebis[6-(2H-benzotriazol-2-yl)-4-tert-octylphenol] ("TINUVIN360" manufactured by BASF)) in which both _R1 and R1 _' in general formula (I) are hydrogen atoms and both R2 and R2' are 1,1,3,3-tetramethylbutyl groups.
The average particle size and transmittance of the ultraviolet absorber in the obtained dispersion were measured in the same manner as in Example 1, and were found to be 32 nm and 78.0%, respectively.

Example 5
An ultraviolet absorbent was dispersed in the same manner as in Example ₂ , except _that the ultraviolet absorbent was changed to compound 2 (2,2'-methylenebis[6-(2H-benzotriazol-2-yl)-4-tert-octylphenol] ("TINUVIN360" manufactured by BASF)) in which both _R1 and R1 _' in general formula (I) are hydrogen atoms and both R2 and R2' are 1,1,3,3-tetramethylbutyl groups.
The average particle size and transmittance of the ultraviolet absorber in the obtained dispersion were measured in the same manner as in Example 1, and were found to be 24 nm and 87.9%, respectively.

Example 6
An ultraviolet absorbent was dispersed in the same manner as in Example ₃ , except _that the ultraviolet absorbent was changed to compound 2 (2,2'-methylenebis[6-(2H-benzotriazol-2-yl)-4-tert-octylphenol] ("TINUVIN360" manufactured by BASF)) in which both _R1 and R1 _' in general formula (I) are hydrogen atoms and both R2 and R2' are 1,1,3,3-tetramethylbutyl groups. The average particle size and transmittance of the ultraviolet absorbent in the obtained dispersion were measured in the same manner as in Example 1, and were found to be an average particle size of 30 nm and a transmittance of 81.9%.

Comparative Example 1
An ultraviolet absorber was dispersed in the same manner as in Example 1, except that the dispersant used was changed to 17.5 parts by weight of a high molecular weight dispersant having an acid value (disperbyk-2015 manufactured by BYK-Chemie, acid value 10 mg KOH/g, active ingredient 40.0 wt%) and 72.5 parts by weight of water. The average particle size and transmittance of the ultraviolet absorber in the obtained dispersion were measured in the same manner as in Example 1, and were found to be an average particle size of 43 nm and a transmittance of 68.5%.

Comparative Example 2
An ultraviolet absorber was dispersed in the same manner as in Comparative Example ₁ , except that the ultraviolet absorber was changed to compound 2 (2,2'-methylenebis[6-(2H-benzotriazol-2-yl)-4-tert-octylphenol] ₍ "TINUVIN360" manufactured by BASF)) in which both _R1 and R1 _' in general formula (I) are hydrogen atoms and both R2 and R2' are 1,1,3,3-tetramethylbutyl groups.
The average particle size and transmittance of the ultraviolet absorber in the obtained dispersion were measured in the same manner as in Example 1, and were found to be 37 nm and 68.2%, respectively.

Comparative Example 3
The ultraviolet absorbent was dispersed in the same manner as in Example 1, except that the ultraviolet absorbent was changed to compound 3 represented by the following chemical formula (II) (2-(5-chloro-2H-benzotriazol-2-yl)-6-tert-butyl-4-methylphenol ("TINUVIN326" manufactured by BASF)).

The average particle size and transmittance of the UV absorber in the resulting dispersion were measured in the same manner as in Example 1, and were found to be 130 nm and 1.3%, respectively.

Comparative Example 4
The ultraviolet absorbent was dispersed in the same manner as in Example 2, except that the ultraviolet absorbent was changed to compound 3 (2-(5-chloro-2H-benzotriazol-2-yl)-6-tert-butyl-4-methylphenol (BASF "TINUVIN326")) as in Comparative Example 3.
The average particle size and transmittance of the ultraviolet absorber in the obtained dispersion were measured in the same manner as in Example 1, and were found to be 119 nm and 1.9%, respectively.

Comparative Example 5
The ultraviolet absorbent was dispersed in the same manner as in Example 3, except that the ultraviolet absorbent was changed to compound 3 (2-(5-chloro-2H-benzotriazol-2-yl)-6-tert-butyl-4-methylphenol (BASF "TINUVIN326")) in Comparative Example 3.
The average particle size and transmittance of the ultraviolet absorber in the obtained dispersion were measured in the same manner as in Example 1, and were found to be 155 nm and 2.1%, respectively.

Comparative Example 6
An ultraviolet absorber was dispersed in the same manner as in Comparative Example 1, except that the ultraviolet absorber was changed to compound 3 (2-(5-chloro-2H-benzotriazol-2-yl)-6-tert-butyl-4-methylphenol ("TINUVIN326" manufactured by BASF)) as in Comparative Example 3. The average particle size and transmittance of the ultraviolet absorber in the obtained dispersion were measured in the same manner as in Example 1, and were found to be 158 nm in average particle size and 4.1% in transmittance.

Comparative Example 7
The ultraviolet absorber was dispersed in the same manner as in Example 1, except that the ultraviolet absorber was changed to compound 4 represented by the following chemical formula (III) (2,2'-(1,4-phenylene)bis-4H-3,1-benzoxazine-4-one (manufactured by Chemipro Chemical Co., Ltd., "KEMISORB500")).

The average particle size and transmittance of the UV absorber in the resulting dispersion were measured in the same manner as in Example 1, and were found to be 90 nm and 1.0%, respectively.

Comparative Example 8
The ultraviolet absorber was dispersed in the same manner as in Example 2, except that the ultraviolet absorber was changed to compound 4 (2,2'-(1,4-phenylene)bis-4H-3,1-benzoxazine-4-one (manufactured by Chemipro Chemical Co., Ltd., "KEMISORB500")) as in Comparative Example 7.
The average particle size and transmittance of the ultraviolet absorber in the obtained dispersion were measured in the same manner as in Example 1, and were found to be 81 nm and 1.7%, respectively.

Comparative Example 9
The ultraviolet absorber was dispersed in the same manner as in Example 3, except that the ultraviolet absorber was changed to compound 4 (2,2'-(1,4-phenylene)bis-4H-3,1-benzoxazine-4-one (manufactured by Chemipro Chemical Co., Ltd., "KEMISORB500")) as in Comparative Example 7.
The average particle size and transmittance of the ultraviolet absorber in the obtained dispersion were measured in the same manner as in Example 1, and were found to be 79 nm and 9.1%, respectively.

Comparative Example 10
The ultraviolet absorber was dispersed in the same manner as in Comparative Example 1, except that the ultraviolet absorber was changed to compound 4 (2,2'-(1,4-phenylene)bis-4H-3,1-benzoxazine-4-one (manufactured by Chemipro Chemical Co., Ltd., "KEMISORB500")) as in Comparative Example 7.
The average particle size and transmittance of the ultraviolet absorber in the obtained dispersion were measured in the same manner as in Example 1, and were found to be 58 nm and 25.4%, respectively.

Table 1 shows the UV absorber, activator and dispersant contained in each dispersion obtained in each of the above examples and comparative examples, as well as the transmittance, absorbance, absorbance ratio, D10, D50, D90 and viscosity.

Compound 1...2,2'-methylenebis[6-(5-chloro-2H-benzotriazol-2-yl)-4-tert-octylphenol]
Compound 2...2,2'-methylenebis[6-(2H-benzotriazol-2-yl)-4-tert-octylphenol]
Compound 3...2-(5-chloro-2H-benzotriazol-2-yl)-6-tert-butyl-4-methylphenol Compound 4...2,2'-(1,4-phenene)-bis[4H-3,1-benzoxazin-4-one]

Comparing the transmittance between the Examples and Comparative Examples, it can be seen that the dispersion using the compound of formula (I) as an ultraviolet absorber according to the present invention and containing a surfactant has a higher transmittance than the other dispersions, and is therefore excellent in transparency.
Comparing the absorbance ratios of the Examples and Comparative Examples, it can be seen that the absorbance ratio of the dispersion in which the compound of formula (I) is used as an ultraviolet absorber according to the present invention and which contains a surfactant is larger than the absorbance ratios of the other dispersions, and thus maintains high transparency while sufficiently blocking the ultraviolet region.

The present invention makes it possible to obtain an aqueous ultraviolet absorbent composition that has excellent transparency and sufficiently blocks ultraviolet rays, and a coating composition using the same.

Claims (4)

The aqueous ultraviolet absorbent composition is an aqueous ultraviolet absorbent composition in which at least an ultraviolet absorbent and a dispersant are present in an aqueous medium, the ultraviolet absorbent being a compound represented by the following general formula (I) and containing a surfactant, the aqueous ultraviolet absorbent composition being characterized in that the ultraviolet absorbent is dispersed with an average dispersed particle diameter of 10 to 35 nm.
General formula (I)

In the formula,
R ₁ and R _1' may be the same or different and each is a hydrogen atom, a halogen atom, a nitro group, a cyano group, a perfluoroalkyl group having 1 to 12 carbon atoms, an R ₃ SO-- group or an R ₃ O ₂ -- group.
_R2 and R2 _' may be the same or different and are an alkyl group having 1 to 12 carbon atoms, an alkyl group having 1 to 12 carbon atoms substituted with a _CO2H group, a phenyl group, a phenylalkyl group containing 1 to 4 carbon atoms in the alkyl moiety, or a cycloalkyl group having 5 to 8 carbon atoms.
_R3 is an alkyl group having 1 to 20 carbon atoms, a hydroxyalkyl group having 2 to 20 carbon atoms, an alkyl group substituted by an alkoxycarbonyl group having 2 to 9 carbon atoms, an alkenyl group having 3 to 18 carbon atoms, a cycloalkyl group having 5 to 12 carbon atoms, a phenylalkyl group having 7 to 15 carbon atoms, an aryl group having 6 to 10 carbon atoms, or the above aryl group substituted by one or two alkyl groups having 1 to 4 carbon atoms, or a 1,1,2,2-tetrahydroperfluoroalkyl group (the perfluoroalkyl portion of this group consists of 6 to 16 carbon atoms). 2. The aqueous ultraviolet absorbent composition according to claim 1 , wherein the dispersant is one or more compounds selected from acrylic copolymers of control polymerization. In the compound of general formula (I),
2. The aqueous ultraviolet absorbent composition according to claim 1 , wherein R ₁ is chlorine or hydrogen, and R ₂ is tert-octyl. 2. A method for producing a coating composition, comprising mixing the aqueous ultraviolet absorbent composition according to claim 1 with a resin component to form a coating liquid.

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