JP5611067B2 - Internal antireflection black paint for optical elements - Google Patents

Description

  The present invention forms a coating film on the edge or edge of an optical element such as a lens or a prism, or a peripheral part such as an edge, and absorbs stray light that causes flare or ghosting. It relates to paint.

  In an optical system configured by combining optical elements such as lenses and prisms, stray light due to diffuse reflection or scattering is generated when light is inserted into the peripheral parts such as the edges and ridges of each optical element. Occurs, which is one of the causes of image quality degradation.

  Therefore, in order to suppress the deterioration of the optical performance due to such stray light, a coating film of a high refractive index black paint is formed on the periphery of the optical element such as an edge or a ridge to prevent internal reflection.

  Therefore, as a paint having such an internal reflection preventing function, a method of containing a black pigment having a refractive index of 1.5 or more and a particle diameter of 0.1 μm or less, a refractive index of 1.5 or more and a particle diameter of 0.1 μm A method containing the following non-black inorganic particles and a black pigment has been proposed. (Patent Document 1).

  However, when using the configuration proposed here for an optical element having a high refractive index of 1.7 or more, which is required recently, the inclusion of high refractive index inorganic particles with respect to the solid content of the coating film in order to obtain a sufficient internal antireflection effect The rate was at least 35% by mass. However, even if such a paint having a high inorganic pigment content is prepared, the stability of the paint is poor, and the coating work itself is difficult due to a sudden increase in viscosity just after the paint is stored at room temperature for several days. I found out that

  For this reason, the development of an internal antireflection black paint for optical elements that has sufficient internal antireflection effects even for optical elements with a high refractive index and that can ensure coating workability even when the paint is stored for a long time. I was waiting.

Japanese Patent Application Laid-Open No. 07-82510

  The present invention provides an internal antireflection black paint for optical elements that has a sufficient internal antireflection effect even for optical elements having a high refractive index, and that can ensure coating workability even when the paint is stored for a long period of time. For the purpose.

The present invention for solving the above problems
In the inner surface antireflection black paint for optical elements containing at least titanium dioxide, carbon black, binder resin, dispersant, and solvent,
The titanium dioxide has a methanol hydrophobization degree of 30% to 80%, a pH of 3.0 to 8.0, an average primary particle size of 7 nm to 50 nm, and the inner surface for an optical element. It is contained in an amount of 35% by mass to 75% by mass with respect to the solid content of the antireflection black paint,
The carbon black has a volatile content of 0.6 mass% to 6.0 mass%, a pH of 3.0 to 8.0, an average primary particle size of 14 nm to 80 nm, and 2% by mass or more and 20% by mass or less based on the solid content of the inner surface antireflection black paint for optical elements,
The dispersant is a combination of a phthalocyanine compound and a polymer dispersant,
The phthalocyanine compound is contained in an amount of 1% by mass to 20% by mass with respect to 100% by mass of the carbon black,
The polymer dispersant has an amine value of 5 mgKOH / g or more and 100 mgKOH / g or less, and is contained in an amount of 5% by mass or more and 40% by mass or less when the total of the titanium dioxide and the carbon black is 100% by mass. An internal reflection-preventing black paint for optical elements.

  According to the present invention, there is provided an internal antireflection black paint for optical elements that has sufficient internal antireflection effects even for optical elements having a high refractive index, and that can ensure coating workability even when the paint is stored for a long period of time. It becomes possible to provide.

It is the cross-sectional schematic which shows an example which applied the inner surface antireflection black paint for optical elements of this invention to the lens for cameras, and formed the antireflection film. It is the schematic of the sample for internal surface reflectance evaluation which applied the internal-surface antireflection black paint for optical elements of this invention to the right-angled triangular prism, and formed the antireflection film. It is the schematic for demonstrating the measuring method of the internal surface reflectance by a spectrophotometer.

Hereinafter, the present invention will be described in detail.
The present invention provides an internal antireflection black paint for optical elements containing at least titanium dioxide, carbon black, a binder resin, a dispersant, and a solvent.
The titanium dioxide has a methanol hydrophobization degree of 30% to 80%, a pH of 3.0 to 8.0, an average primary particle size of 7 nm to 50 nm, and the inner surface for an optical element. It is contained in an amount of 35% by mass to 75% by mass with respect to the solid content of the antireflection black paint,
The carbon black has a volatile content of 0.6 mass% to 6.0 mass%, a pH of 3.0 to 8.0, an average primary particle size of 14 nm to 80 nm, and 2% by mass or more and 20% by mass or less based on the solid content of the inner surface antireflection black paint for optical elements,
The dispersant is a combination of a phthalocyanine compound and a polymer dispersant,
The phthalocyanine compound is contained in an amount of 1% by mass to 20% by mass with respect to 100% by mass of the carbon black,
The polymer dispersant has an amine value of 5 mgKOH / g or more and 100 mgKOH / g or less, and is contained in an amount of 5% by mass or more and 40% by mass or less when the total of the titanium dioxide and the carbon black is 100% by mass. It is characterized by.

  FIG. 1 is a schematic cross-sectional view of an example in which the antireflection black paint of the present invention is applied to a camera lens which is one form of an optical element. Here, the antireflective black paint film 2 of the present invention is formed on the edge of the lens 1. This coating film 2 suppresses or prevents light (stray light) 4 that reaches the edge of the incident light 3 that enters from the outside of the lens and reflects from the inner surface, and suppresses phenomena such as ghost and flare in an image photographed by the camera. Yes.

The degree of suppression / prevention of the internal reflection light is determined by, for example, forming the coating film 2 on the entire bottom surface of the right triangular prism 5 as shown in FIG. 2 and measuring the internal reflectivity by the measurement method as shown in FIG. It can be measured.
The light emitted from the light source 6 is passed through the polarizing plate 12 set to N-polarized light, and the incident light 7 collected by the slit 13 is inserted into the right triangular prism 5 to be internally reflected by the coating film 2. The reflected light 8 emitted from the triangular prism (inner surface) is received by an integrating sphere / light receiver 9 and the light intensity is measured. At this time, the measured values of the internal reflection light 8 are the direction of the polarizing plate 12, the degree of condensing the incident light 7 by the slit 13, the size of the right triangular prism 5, the distance A to the integrating sphere 9, and the integrating sphere 9 It should be noted that the value varies depending on the size and the size B of the opening diameter.
In the right triangular prism 5 without the coating film 2, when the refractive index is n and the refractive index of air is 1.0, the critical angle of total reflection of incident light 7 on the prism bottom surface is perpendicular to the prism bottom surface. Assuming that the angle formed by the line (perpendicular line) 10 is θ, the following formula is obtained according to Snell's law.
θ = sin ⁻¹ (sin 90 ° / n)
That is, in the right triangular prism 5 with n = 1.8, θ = sin ⁻¹ (sin 90 ° / 1.8) ≈33.7 ° is the critical angle, and the incident light 7 is incident from 33.7 ° to 90 °. At the corner, total reflection occurs.
In order to narrow the angle region in which such total reflection occurs, it is effective to make the refractive index of the coating film 7 close to or higher than the refractive index of the right triangular prism.

According to the antireflective black paint of the present invention, titanium dioxide (refractive index 2.5 to 2.7), which is a high refractive agent in order to improve the refractive index of the coating film, is 35% by mass or more based on the solid content of the paint With high content, it is possible to contain more than 2% of carbon black as a light absorber with respect to the solid content of the paint, and the anti-reflective black paint obtained is highly stable over time. It is suitable as an inner surface antireflection black paint.
In the present invention that has made it possible to achieve this, the titanium hydrophobization degree of the titanium dioxide is 30% or more and 80% or less and the pH is limited to 3.0 or more and 8.0 or less, Both pigments that are likely to occur normally by using a carbon black having a volatile content of 0.6 mass% or more and 6.0 mass% or less and a pH limited to 3.0 or more and 8.0 or less. Aggregation between them can be prevented.
Furthermore, in order to improve the temporal dispersion stability of the titanium dioxide and the carbon black (hereinafter sometimes abbreviated as “both pigment particles”), a phthalocyanine compound and a polymeric dispersant are used in combination as a dispersant, Maintaining the effect of preventing aggregation between the two pigments by adsorbing a polymer dispersant having an amine value of 5 mg / KOH or more and 100 mg / KOH or less to the polar part of the surface of both pigment particles. I let you. In addition, carbon black with high self-aggregation power efficiently adsorbs phthalocyanine compounds having a π-electron conjugated system as a planar structure on the hydrophobic surface, and does not hinder the adsorption of polymeric dispersants to carbon black. Therefore, the present invention was successfully found by limiting the pH to 3.0 to 8.0.

Here, the polymer dispersant and the phthalocyanine compound are dissolved in the solvent used in the antireflective black paint of the present invention and separated to the molecular level so as to be effectively adsorbed on both pigment particle surfaces. Is desirable.
The characteristics and manufacturing methods of each material contained in the antireflection paint of the present invention that have led to the solution of this problem are as follows.

(titanium dioxide)
As titanium dioxide, those synthesized by a wet method such as a sulfuric acid method or a chlorine method can be used. When synthesized by these wet methods, it is manufactured by adding a base such as ammonia and neutralizing, but by adjusting the amount of addition of this base and adjusting the cleaning method of the obtained titanium dioxide, The pH can be adjusted in the range of about 2.0 to 10.0. The titanium dioxide used in the present invention is adjusted to pH 3.0 or more and 8.0 or less. When the pH is less than 3.0, there is a concern that aggregation occurs due to the interaction with carbon black having a relatively basic functional group. On the other hand, when the pH is greater than 8.0, the affinity with the polymer dispersant used in the present invention is weak and aggregation tends to occur.

The pH of titanium dioxide was measured by measuring 5.0 g of titanium dioxide in a beaker, 100 ml of distilled water (for high-performance liquid chromatography, manufactured by Kishida Chemical Co., Ltd.), ethyl alcohol (pure content 99.5% or more, for high-performance liquid chromatography, kida 5 ml of Chemical Co., Ltd. is added, and the beaker is covered with a watch glass (so as not to be sealed) and boiled for 5 minutes. After cooling to room temperature and supplementing and mixing with distilled water in an amount reduced by boiling, the supernatant can be determined with a glass electrode pH meter.
Further, the methanol hydrophobization degree of titanium dioxide used in the present invention needs to be 30% or more and 80% or less. If it is lower than 30%, a large amount of hydrophilic functional groups are present on the surface of titanium dioxide, so that self-aggregation of titanium dioxide itself tends to occur, and as a result, the aggregates settle and cause caking. On the other hand, if it is larger than 80%, the functional group that ensures affinity with the polymer dispersant on the titanium dioxide surface is extremely reduced, and the hydrophobic functional groups are aggregated by a moderate intermolecular force, causing an increase in viscosity over time. End up.
In order to control the degree of methanol hydrophobization of titanium dioxide, for example, surface treatment with an alkylsilane compound, a silane coupling agent, silicone, titanate coupling agent, zirconia, alumina, silica, etc. can be mentioned. It is possible to adjust the amount of the surface treating agent by using one kind or a plurality of kinds in combination.
Preferably, hydrophobic treatment with an alkylsilane compound, specifically, methylmethoxysilane, n-propyltrimethoxysilane, diisopropyldimethoxysilane, isobutyltrimethoxysilane, 3,3,3-trifluoropropyltrimethoxysilane, etc. It is done.

The methanol hydrophobization degree (%) of titanium dioxide is as follows. At room temperature (about 25 ° C.), 0.1 g of a sample is weighed in a 200 ml beaker, and 50 g of ion-exchanged water is added and stirred with a magnetic stirrer. Into this, about 2 ml of methanol is dropped from the burette every 10 seconds, and the degree of methanol hydrophobization (%) is calculated from the following equation with the end of the state where the sample that has floated on the liquid surface is completely removed.
Methanol hydrophobicity (%) = [Titration / (Titration + 50)] × 100

When surface treatment is performed on titanium dioxide as described above, the pH may slightly change from that before the surface treatment, but the final degree of methanol hydrophobization is 30% to 80% and the pH is 3 If it is within the range of 0.0 or more and 8.0 or less, there is no problem.
Moreover, it is preferable that the average primary particle diameter of the titanium dioxide used by this invention is 7 nm or more and 50 nm or less.
Further, the titanium dioxide used in the present invention needs to be 35% by mass or more and 75% by mass or less with respect to the solid content of the paint. When the amount is less than 35% by mass, a sufficient inner surface antireflection effect cannot be obtained when the refractive index of the optical element is 1.7 or more, and further 1.8 or more. On the other hand, when the amount is more than 75% by mass, the amount of the binder constituting the coating film is extremely small, so that there is a concern that the coating film strength becomes weak and the film is easily peeled off from the optical element.

Here, since the water | moisture content normally adheres to the surface of a titanium dioxide particle about several mass%, when calculating | requiring the amount T (mass%) of titanium dioxide in paint solid content, it converts as follows.
1) First, the solid content (mass%) of titanium dioxide excluding moisture contained in the titanium dioxide particles used for blending is determined. X1 (g) of titanium dioxide powder is weighed in an aluminum dish that is stored in a desiccator and sufficiently dried. Next, this aluminum dish containing titanium dioxide is put into a dryer at 140 ° C. for 1 hour to volatilize water adhering to the titanium dioxide surface. The aluminum pan taken out from the dryer is stored in a desiccator and slowly cooled to room temperature. The dry titanium dioxide remaining in the aluminum pan is weighed by X2 (g). And solid content A1 (mass%) of titanium dioxide is calculated | required by a following formula.
A1 = [(X2) / (X1)] / 100
2) Next, a paint using this titanium dioxide is blended and prepared, and the blending amount (mass%) of titanium dioxide with respect to the entire paint is set to A2.
3) Store the blended and prepared paint in a desiccator and weigh Z1 (g) into a well-dried aluminum dish. The aluminum dish containing the paint is allowed to stand at room temperature for 30 minutes, and then placed in a dryer at 140 ° C. for 1 hour to be dried and cured. The aluminum pan taken out from the dryer is stored in a desiccator and slowly cooled to room temperature. Z2 (g) is measured for the dried and hardened paint solids remaining in the aluminum pan.
4) From the above measurement results, the amount T (mass%) of titanium dioxide in the solid content of the paint is obtained by the following formula 1.
T = [(Z1) × (A2) × (A1)] / [(Z2) × 100] (Formula 1)
In the present invention, the titanium dioxide needs to be contained in an amount of 35% by mass to 75% by mass with respect to the solid content of the paint. When the amount is less than 35% by mass, a sufficient inner surface antireflection effect cannot be exhibited. On the other hand, when it is more than 75% by mass, the ratio of the binder resin in the solid content of the coating becomes too small, and the strength of the coating film may be lowered.
Moreover, it is preferable that the average primary particle diameter of the titanium dioxide used for this invention is 7 nm or more and 50 nm or less.
Here, the average primary particle diameter of titanium dioxide can be obtained from an observation image of a transmission electron microscope.
In the present invention, the titanium dioxide may be used in a mixture of two or more types having different hydrophobizing treatments, different pH values, and the like.

(Carbon black)
In the present invention, carbon black is used as a light absorber. Carbon black can absorb light with wavelengths from the infrared to the ultraviolet region and is an excellent material as a light absorber. However, if it is not uniformly dispersed in the paint, it absorbs light (internal antireflection performance). ) Will fall.
In particular, when other dispersed particles are present in the paint (corresponding to titanium dioxide in the present invention), care must be taken in selecting the compounding material so that aggregation does not occur due to the interaction with the dispersed particles.

In particular, the coating material of the present invention contains and disperses 35% by mass or more and 75% by mass or less of titanium dioxide having the above characteristics with respect to the solid content of the coating material.
Therefore, the present invention is characterized in that a carbon black to be used has a volatile content of 0.6% by mass or more and 6.0% by mass or less and a pH of 3.0 or more and 8.0 or less.
If the volatile content of carbon black is less than 0.6% by mass, there will be very few hydrophilic functional groups present on the surface of the carbon black and the hydrophobicity will be too high, making it difficult to adsorb the polymer dispersant used in the present invention. The self-aggregation between the carbon black particles tends to occur. On the other hand, when the amount is more than 6.0% by mass, there are too many hydrophilic functional groups present on the surface of the carbon black, the affinity with the phthalocyanine compound becomes weak, and the carbon black particles are not properly dispersed. Here, the volatile matter of the carbon black is a material in which the surface functional groups of the carbon black are eliminated in the form of CO, CO ₂ , H ₂ O, etc. The carbon black is put in a crucible and heated at 950 ° C. for 7 minutes. This is expressed as a percentage (%) of weight loss over time.
Also, if the pH of the carbon black is less than 3.0, there are too many acidic hydrophilic functional groups present on the surface of the carbon black, and there is a concern that they will interact and aggregate with titanium dioxide having a relatively basic functional group. There is. On the other hand, if the pH is greater than 8.0, the number of acidic hydrophilic functional groups present on the surface of the carbon black will be too small, and the polymer dispersant used in the present invention will be difficult to adsorb, and self-aggregation between the carbon black particles will occur. It becomes easy to happen.
The pH of carbon black can be obtained by the same method as described above, except that titanium dioxide is replaced with carbon black in the method of measuring the pH of titanium dioxide.

Furthermore, the average primary particle size of the carbon black used in the present invention is preferably 14 nm or more and 80 nm or less, and the DBP absorption is preferably 40 ml / 100 g or more and 170 ml / 100 g or less. Here, the average primary particle diameter of carbon black can be obtained from an observation image of a transmission electron microscope. Here, the DBP absorption amount conforms to JIS K6217.
These carbon blacks may be used alone or in combination of two or more.

Furthermore, the carbon black needs to be contained in an amount of 2% by mass to 20% by mass with respect to the solid content of the paint. If the amount of carbon black is less than 2% by mass, the light absorption of carbon black becomes weaker than the light scattering property of titanium dioxide, and the internal reflectance rapidly increases. On the other hand, when the content is more than 20% by mass, the dispersion stability of carbon black in the paint deteriorates and the storage stability with time deteriorates.
Further, it is considered that about several mass% of water is usually attached to the surface of the carbon black used in the present invention as well as titanium dioxide. The amount of carbon black (% by mass) in the solid content of the coating can be similarly determined by substituting “titanium dioxide” with “carbon black” for “Formula 1” for determining the amount of titanium dioxide (% by mass).
The carbon black used in the present invention is not particularly limited, and examples thereof include channel black, oil furnace black, gas furnace black, thermal black, acetylene black and bone black. Among these carbon blacks, channel black, gas furnace black and oil furnace black are preferably excellent in dispersibility.

上記構造式において、Ｍは中心金属あるいは無金属（配位位置の４つの窒素のうち２つは水素が結合する）、Ｘ_１〜Ｘ_４はＣｌ、Ｂｒ、アルキルスルホニル、カルボキシル、カルボン酸塩、カルボン酸エステル、チオール、チオニル、チオエステル、イミン、イミドメチル、フタルイミドメチル、クロロメチル、クロロスルホニル、スルホン酸塩、スルホニルアミド、スルフィド、スルフォキシド、アルキルアミド、アルキル、アルキルアミノ、芳香族アミンなどの置換基を表し、ｎ、ｍ、ｌ、ｋは0から４の整数である。
また、フタロシアニンの中心金属は、イオン結合的な要素の強いＮａ、Ｋ、Ｂｅ、Ｃａ、Ｂａ、Ｃｄ、Ｍｇ及びＨｇ等の元素や、共有結合的要素の強いＣｕ、Ｆｅ、Ｚｎ、Ｃｏ、Ｐｔ、Ｃｒ、Ｎｉ及びＰｔ等が挙げられる。 (Phthalocyanine compound)
The structure of the phthalocyanine compound used in the present invention is represented by the following formula.

In the above structural formula, M is a central metal or no metal (two of the four nitrogen atoms at the coordination position are bonded with hydrogen), X _{1 to} X ₄ are Cl, Br, alkylsulfonyl, carboxyl, carboxylate, Substituents such as carboxylic acid ester, thiol, thionyl, thioester, imine, imidomethyl, phthalimidomethyl, chloromethyl, chlorosulfonyl, sulfonate, sulfonylamide, sulfide, sulfoxide, alkylamide, alkyl, alkylamino, aromatic amine, etc. N, m, l and k are integers from 0 to 4.
The central metal of phthalocyanine is composed of elements such as Na, K, Be, Ca, Ba, Cd, Mg and Hg, which have strong ion binding elements, and Cu, Fe, Zn, Co, Pt, which have strong covalent elements. , Cr, Ni, Pt and the like.

The above phthalocyanine compounds can be synthesized by various methods. For example, a method of synthesizing from diiminoisoindolenin in the presence of a metal salt, a method of using phthalonitrile as a precursor in the presence of a metal chloride (phthalonitrile method), anhydrous phthalate Examples include a method using an acid, a metal salt, and urea (Weiler method). Among these, a copper phthalocyanine compound is particularly preferable.
Further, a metal-free phthalocyanine compound can be synthesized by directly synthesizing from diiminoisoindolenine or phthalonitrile (1,2-dicyanobenzene), and can be used as the phthalocyanine compound of the present invention.

In general, there are various phthalocyanine compounds, but the phthalocyanine compound used in the present invention is adsorbed on the hydrophobic surface portion of the carbon black used in the present invention in the paint, and is used to prevent aggregation between the carbon blacks. The pH of the phthalocyanine compound used in the present invention is preferably 3.0 or more and 8.0 or less.
Here, the pH of the phthalocyanine compound can be determined in the same manner as described above, except that titanium dioxide is replaced with a phthalocyanine compound in the method of measuring the pH of titanium dioxide.

As the phthalocyanine compound that can be used in the present invention, for example, the following are commercially available.
VALIFAST BLUE2670 (pH 7.7) manufactured by Orient Chemical Industries, Ltd. Aizen Spiro Blue 2BNH (pH 7.5) manufactured by Hodogaya Chemical Co., Ltd. EFKA6745 (pH 4.5) manufactured by BASF Japan Ltd. Nippon Lubrizol Corporation, SOLSPERS5000 (pH 3.8). BYK-SYNERGIST 2100 (pH 6.1) manufactured by Big Chemie Japan Co., Ltd.
0.1-100 mass parts is preferable with respect to 100 mass parts of electroconductive fine particles, and, as for the addition amount of a phthalocyanine compound, More preferably, it is 1-50 mass parts. When the amount is less than 0.1 parts by mass, the effect of suppressing sedimentation and resistance change of the conductive particles is reduced, and when the amount is more than 100 parts by mass, the phthalocyanine compound itself starts to reaggregate.
The phthalocyanine compound is preferably contained in an amount of 1% by mass to 20% by mass with respect to 100% by mass of the carbon black.

(Polymer dispersant)
The polymer dispersant used in the present invention is used to adsorb and stabilize the dispersion on the surfaces of carbon black and titanium dioxide used in the present invention.
The polymer dispersant used in the present invention means a dispersant having a weight average molecular weight of 1,000 or more. Preferably it is the range of weight average molecular weight 2,000-300,000, More preferably, it is the range of weight average molecular weight 3,000-10,000.
The main chain skeleton of the polymer dispersant is not particularly limited, and examples thereof include a polyurethane skeleton, a polyacryl skeleton, a polyester skeleton, a polyamide skeleton, a polyimide skeleton, a polyurea skeleton, and the like, from the viewpoint of storage stability of the ink composition. A polyurethane skeleton, a polyacryl skeleton, and a polyester skeleton are preferable. The structure of the polymer dispersant is not particularly limited, and examples thereof include a random structure, a block structure, a comb structure, and a star structure. Similarly, in terms of storage stability, a block structure or a comb structure. Is preferred.

Furthermore, the polymer dispersant used in the present invention is required to have an amine value of 5 mgKOH / g or more and 100 mgKOH / g or less. Here, the amine value represents an amine value per 1 g of the solid content of the polymer dispersant, and is a value converted to an equivalent of potassium hydroxide after being obtained by a potentiometric titration method using a 0.1N hydrochloric acid aqueous solution.
The value of the amine value is important as an index of the number of basic functional groups present in the polymer dispersant molecule. When the amine value is less than 5 mgKOH / g, the hydrophilicity of titanium dioxide and carbon black used in the present invention is The affinity with the functional group becomes weak, and the dispersion stability of both pigment particles becomes poor. On the other hand, if the amine value is larger than 100 mgKOH / g, the number of basic functional groups in the polymer dispersant molecule becomes too large, and the polymer dispersant causes bridging aggregation of both pigment particles. The viscosity of the paint may increase.

  The polymer dispersant is contained in an amount of 5% by mass to 40% by mass when the total of carbon black and titanium dioxide used in the present invention is 100% by mass. If it is less than 5% by mass, the polymer dispersant cannot be adsorbed on the entire surface of carbon black and titanium dioxide, and the state in which both pigments are dispersed in the paint cannot be maintained. On the other hand, when the amount is more than 40% by mass, the strength of the coating film becomes weak and the coating film may be peeled off from the optical element of the base material.

As the polymeric dispersant that can be used in the present invention, for example, the following are commercially available.
BASF Japan Ltd., EFKA series 4008 (amine value 15.8 mgKOH / g), 4009 (amine value 19.2 mgKOH / g), 4010 (amine value (11.8 mgKOH / g), 4015 (amine value 21.0 gKOH) / G), 4020 (amine number 13.8 mgKOH / g), 4046 (amine number 47.5 mgKOH / g), 4047 (amine number 48.6 mgKOH / g), 4050 (amine number 30.0 mgKOH / g), 4060 ( (Amine value 26.7 mgKOH / g) SOLSPERS series 13240 (amine value 93.5 mgKOH / g), 20000 (amine value 32.1 mgKOH / g), 24000SC (amine value 41.6 mgKOH / g) manufactured by Nippon Lubrizol Corporation ), 26000 (amine number 37.). mgKOH / g), 32000 (amine value 31.2 mgKOH / g), 71000 (amine value 77.4 mgKOH / g) Ajinomoto Fine Techno Co., Ltd., Ajisper series PB821 (amine value 9.0 mgKOH / g), PB822 ( Amine value 13.0 mg KOH / g).

(Binder resin)
The binder resin used in the present invention is not particularly limited as long as it is a resin that adheres to the surface of the optical element that is the object to be coated and has a coating film strength that is not harmful to practical use. , Polyurethane resin, acrylic resin, vinyl resin, polyester resin, silicone resin, fluororesin, phenol resin, nitrocellulose, etc., preferably epoxy resin, polyurethane resin, acrylic resin, vinyl resin, polyester resin, silicone resin More preferably, an epoxy resin, a polyurethane resin, an acrylic resin, or a silicone resin is used.

Epoxy resin is a general term for compounds having two or more oxirane rings (epoxy groups) in the molecule, and usually has a curing agent (amine, acid or acid anhydride, basic active hydrogen compound, imidazoles, etc.) It can be used as a two-component curable coating in combination with a hydrogen compound. It is also possible to add a catalyst for controlling the curing reaction rate.
Examples of the epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, brominated epoxy resin, bisphenol S type epoxy resin, diphenyl ether type epoxy resin, hydroquinone type epoxy resin, naphthalene type epoxy resin, biphenyl type epoxy resin, and fluorene. Type epoxy resin, bisphenol A type novolac epoxy resin, phenol novolac type epoxy resin, orthocresol novolac type epoxy resin, dicyclopentadiene phenol type epoxy resin, trishydroxyphenylmethane type epoxy resin, trifunctional type epoxy resin, tetraphenylol Ethane type epoxy resin, tetrafunctional type epoxy resin, hydrogenated bisphenol A type epoxy resin, bisphenol A nucleated polyol type epoxy resin, Heterocyclic epoxies such as propylene glycol type epoxy resin, glycidyl ester type epoxy resin, glycidyl amine type epoxy resin, glioxal type epoxy resin, alicyclic epoxy resin, alicyclic polyfunctional epoxy compound, triglycidyl isocyanate (TGIC) Resin.

  Examples of amine curing agents include aliphatic polyamines such as ethylenediamine, diethylenetriamine, and triethylenetetramine, alicyclic polyamines such as isophoronediamine and 1,3-bisaminomethylcyclohexane, and aromatic polyamines such as diaminodiphenylmethane and diaminodiphenylsulfone. Obtained by reacting secondary amines such as linear diamine, tetramethylguanidine, triethanolamine, piperidine, pyridine, benzyldimethylamine or tertiary amines, dimer acid and polyamines such as diethylenetriamine and triethylenetetramine. And polyamidoamine.

  Examples of the acid or acid anhydride curing agent include polycarboxylic acids such as adipic acid, azelaic acid, trimellitic acid, pyromellitic acid and decanedicarboxylic acid, phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, Aromatic acid anhydrides such as 3,3 ′, 4,4′-benzophenonetetracarboxylic anhydride, cyclic aliphatic acid anhydrides such as maleic anhydride, succinic anhydride, tetrahydrophthalic anhydride, and methyltetrahydrophthalic anhydride And aliphatic acid anhydrides such as polyadipic acid anhydride, polyazeline acid anhydride, polysebacic acid anhydride, dodecenyl succinic acid anhydride, and poly (ethyl) octadecanedioic acid anhydride.

  Examples of the basic active hydrogen compound include organic acid dihydrazide.

  Examples of imidazoles include 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-heptanedecylimidazole, and the like.

  Examples of the catalyst include tertiary amine, imidazole, boron trifluoride-amine complex and the like.

  The polyurethane resin can be used as a two-component curable coating material using a compound having two or more hydroxyl groups (also referred to as polyol) and a compound having two or more isocyanate groups (also referred to as isocyanate compound) as a curing agent. In addition to the above hydroxyl groups, isocyanate compounds also undergo a curing reaction with active hydrogen compounds having functional groups such as amino groups, mercapto groups, and carboxyl groups, so these active hydrogen compounds can be used in combination with these active hydrogen compounds or in the polyol molecule. It is possible to adjust the strength of the cured coating film and the stability of the paint by introducing a hydrogen functional group. In addition, a catalyst may be added for controlling the curing reaction rate. In addition, the isocyanate compound can be made into a one-component curable coating material that can coexist with a polyol in a coating material and can be cured by heating at the time of forming a coating film by masking the isocyanate group with a blocking agent in advance. . In addition, by increasing the molecular weight of the isocyanate compound, it is possible to obtain a moisture curable coating that slows the curing reaction and reacts with moisture in the atmosphere to cure.

  Examples of the polyol include polyether polyol, polyester polyol, silicone glycol, polyolefin polyol, castor oil polyol, hydrogenated castor oil polyol, acrylic polyol, phosphorus-containing polyol, halogen-containing polyol, polymer polyol, phenol-based polyol, and 1,4-butane. Examples thereof include polyhydric alcohols such as diol, 1,5-pentanediol, 1,6-hexanediol, ethylene glycol, propylene glycol, glycerin and trimethylolpropane and derivatives thereof.

  Examples of the polyether polyol include polyethylene polyol, polypropylene polyol, and polytetramethylene ether glycol.

  Examples of polyester polyols include the following. Examples include polyethylene glycol adipate, diethylene adipate glycol, butylene glycol adipate, diethylene glycol adipate, polycaprolactone polyol, lactone-modified styrene-acrylic alcohol copolymer, lactone-modified acrylic monomer, polycarbonate polyol, caprolactone-modified polycarbonate diol, and caprolactone-modified acrylic polyol. .

  Examples of silicone glycols include reactive silicone oils that contain an active hydroxyl group in the molecule.

  Examples of the polyolefin-based polyol include polybutadiene polyol, hydrogenated polybutadiene polyol, and hydrogenated isoprene polyol.

  The acrylic polyol is obtained by copolymerizing an acrylic (methacrylic) monomer having a hydroxyl group, an acrylic (methacrylic) acid ester, styrene and the like.

  The phosphorus-containing polyol can be obtained by adding alkylene oxide to a phosphoric acid compound. The halogen-containing polyol can be obtained by ring-opening polymerization of epichlorohydrin or trichlorobutylene oxide.

  Examples of the polymer polyol include those obtained by polymerizing an ethylenically unsaturated monomer in the presence of a polymerization initiator in the polyol.

  Examples of the phenolic polyol include monocyclic polyhydric phenols such as pyrogallol, hydroquinone, and phloroglucin; bisphenols such as bisphenol A and bisphenol sulfone; and phenol and formaldehyde condensates (novolaks).

  Among the polyols listed above, preferred are polyether polyol, polyester polyol, acrylic polyol, and polycarbonate polyol. Moreover, you may use these polyols in mixture of 2 or more types as needed.

  The isocyanate compound is not particularly limited as long as it is a compound having two isocyanate groups in one molecule. For example, aliphatic diisocyanates such as hexamethylene diisocyanate (HMDI) and trimethylhexamethylene diisocyanate (TMDI); isophorone diisocyanate Alicyclic diisocyanates such as (IPDI); aromatic-aliphatic diisocyanates such as xylylene diisocyanate (XDI); aromatic diisocyanates such as tolylene diisocyanate (TDI) and 4,4-diphenylmethane diisocyanate (MDI); Hydrogenated diisocyanates such as dimer acid diisocyanate (DDI), hydrogenated TDI (HTDI), hydrogenated XDI (H6XDI), hydrogenated MDI (H12MDI); It can be mentioned adducts of a polyhydric alcohol such as these and trimethylol propane, water or a low molecular weight polyester resin; dimers, trimers, 4 polyisocyanates mer or more multimers.

  Since the urethane curing reaction starts when the polyol and the isocyanate compound are mixed in the paint, the pot life is short. In order to extend this pot life, it can also be used as a blocked isocyanate compound in which the reactive group (isocyanate group) of the isocyanate compound is blocked with an appropriate blocking agent. The blocking agent is not particularly limited, and examples thereof include oxime blocking agents such as methyl ethyl ketoxime, acetoxime, cyclohexanone oxime, acetophenone oxime, and benzophenone oxime; phenol blocking agents such as m-cresol and xylenol; methanol, ethanol, Alcohol-based blocking agents such as butanol, 2-ethylhexanol, cyclohexanol, ethylene glycol monoethyl ether; Lactam-based blocking agents such as ε-caprolactam; Diketones such as diethyl malonate and acetoacetate; Examples include mercaptan blocking agents; urea blocking agents such as thiourea; imidazole blocking agents; carbamic acid blocking agents. Of these, lactam blocking agents, oxime blocking agents, alcohol blocking agents, and diketone blocking agents are preferred.

  Examples of the catalyst include triethylenediamine, tetramethylguanidine, N, N, N′N′-tetramethylhexane-1,6-diamine, N, N, N′N ″ N ″ -pentamethyldiethylenetriamine, bis ( And tertiary amines such as 2-dimethylaminoethyl) ether, 1,2-dimethylimidazole, N-methyl-N ′-(2-dimethylamino) ethylpiperazine, and diazabicycloundecene. In addition, stannous octoate, dibutyltin diacetate, dibutyltin dilaurate, dibutyltin thiocarboxylate, dibutyltin thiocarboxylate, dibutyltin dimaleate, dioctyltin thiocarboxylate, dioctyltin thiocarboxylate, phenylmercury propionate, octenoic acid Organic metal compounds such as lead can be mentioned. Furthermore, the carboxylate of the said tertiary amine etc. are mentioned.

  The acrylic resin can be used as a polymer composed of (meth) acrylate ([(meth) acrylate] means both acrylate and methacrylate) and a copolymer thereof. Examples of the (meth) acrylate include alkyl (meth) acrylates such as methyl, ethyl, propyl, or butyl (meth) acrylate; hydroxymethyl, hydroxyethyl, hydroxypropyl, hydroxybutyl, hydroxypentyl (meth) acrylate, and the like. And hydroxyalkyl (meth) acrylates.

  Examples of the polymer and copolymer include methyl methacrylate polymer, methyl methacrylate / butyl methacrylate copolymer, methyl methacrylate / butyl acrylate / hydroxyethyl methacrylate / methacrylic acid copolymer, and styrene / (meth) acrylate copolymer. Polymers, and other (meth) acrylates as the main component include copolymers of comonomers such as acrylic acid, methacrylic acid, styrene, acrylamide, vinyltoluene, glycidyl methacrylate, and hydroxyethyl acrylate.

  Further, for example, by introducing a monomer having a hydroxyl group into the above copolymer, a two-component room temperature curable paint using an isocyanate compound as a curing agent, or a baking curable coating using a melamine resin as a curing agent may be used. Moreover, it is good also as a thermosetting coating material which uses an epoxy resin or an acid anhydride as a hardening | curing agent by introduce | transducing the monomer which has a carboxyl group and an epoxy group into the said copolymer, for example. In addition, a self-curing coating material may be obtained by copolymerizing an alkoxysilyl group monomer or the like with the copolymer.

  Examples of the vinyl resin include a vinyl chloride resin and a vinyl acetate resin. The vinyl chloride resin is obtained by suspending or emulsion polymerizing vinyl chloride alone or together with vinylidene chloride, vinyl acetate, vinyl propionate or the like. When these vinyl chloride resins are used, a plasticizer (for example, dioctyl phthalate) or a stabilizer (for example, metal soap, epoxy compound, amine compound, etc.) can be added and used as a sol type paint.

  The vinyl acetate resin is obtained by emulsion polymerization using vinyl acetate alone or together with ethylene, a fatty acid vinyl ester monomer or the like using polyvinyl alcohol as a protective colloid.

Examples of the polyester resin include alkyd resins and unsaturated polyesters.
The alkyd resin is obtained by, for example, heating a polyhydric alcohol such as ethylene glycol, glycerin (glycerol) or pentaerythritol and a dibasic acid such as phthalic anhydride or maleic anhydride to form an ester bond. It may be modified with dry oil (such as linseed oil, paulownia oil, soybean oil) or unsaturated fatty acids (linoleic acid, oleic acid, etc.) constituting them, or dehydrated castor oil. Of these oils, when the oil length is 45% or more, the medium / long oil alkyd resin has many unsaturated double bonds, so add a curing catalyst (dryer) such as lead naphthenate, cobalt, manganese, etc. It may be used as a one-component room temperature curable coating that is crosslinked by oxidative polymerization.
The unsaturated polyester resin is obtained by, for example, ester-bonding a polyhydric alcohol and an unsaturated polyvalent carboxylic acid to introduce a radical polymerizable double bond in the main chain. A vinyl compound that is a copolymerizable monomer is added to the obtained paint, and an organic peroxide-based initiator and a curing catalyst (dryer) are added to form a room-temperature-curing paint, or UV or electron beam curing is possible. it can.

  Examples of the polyhydric alcohol component include ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, dipropylene glycol, 1,3-butylene glycol, 2,3-butylene glycol, 1,6-hexanediol, 2-ethyl- Examples include 1,3-hexanediol, 2,2,4-trimethyl-1,3-pentanediol, neopentyl glycol, trimethylol ethane, trimethylol propane, glycerin, pentaerythritol, and bisphenol / alkylene oxide adducts. it can.

  Examples of the unsaturated polyvalent carboxylic acid include maleic anhydride, maleic acid, itaconic anhydride, itaconic acid, fumaric acid, endomethylenetetrahydrophthalic anhydride and the like. Further, other polyvalent carboxylic acids (aromatic polyvalent carboxylic acids and saturated polyvalent carboxylic acids) can be used in combination with the unsaturated polyvalent carboxylic acids. Examples of other polyvalent carboxylic acids include phthalic anhydride, phthalic acid, terephthalic acid, isophthalic acid, tetrahydrophthalic acid, tetrahydrophthalic anhydride, succinic acid, citraconic acid, adipic acid, and sebacic acid.

  Examples of the vinyl compound include styrene, vinyl acetate, methyl (meth) acrylate, vinyl toluene, and the like.

  The unsaturated polyester resin may be modified with, for example, paulownia oil, linseed oil, soybean oil, cottonseed oil, safflower oil, coconut oil, or the like.

  Further, the unsaturated polyester resin may be blended with a curing catalyst when used as a paint to form a two-part curable paint, or may be blended in advance to form a one-part curable paint.

  Specific examples of the curing catalyst include inorganic acids such as hydrochloric acid, nitric acid, phosphoric acid and boric acid, organic acids such as acetic acid, formic acid, maleic acid, phthalic acid, benzoic acid and p-toluenesulfonic acid, dibutyltin laurate, dibutyltin octyl Organic tin compounds such as acrylate, dibutyltin acetate and dioctyltin laurate, organic titanium compounds such as tetrabutyl titanate, tetrapropyl titanate and tetrabutoxy titanate, phosphate esters such as monomethyl phosphate and monoethyl phosphate, γ-aminopropyltrimethoxy Silane coupling agents such as silane, N-β-aminoethyl-γ-aminopropyltrimethoxysilane, γ-ureidopropyltriethoxysilane, tris (acetylacetonato) aluminum, tris (ethylacetoacetate) alumini Organoaluminum compounds such as tetrabutyl zirconate, butoxytris (acetylacetonate), etc., amine compounds such as ethylenediamine, diethylenetriamine, piperazine, metaphenylenediamine, diethanolamine, triethanolamine, sodium hydroxide, water Alkali compounds such as potassium oxide, epoxy compounds and the like can be mentioned.

  Among these, inorganic acids, organic acids, organic tin compounds, organic aluminum, and the like are preferable. A curing catalyst can be used individually by 1 type, or can use 2 or more types together. Although the usage-amount of a curing catalyst can be suitably selected from a wide range with the kind of catalyst, for example, when using hydrochloric acid, 0.1-2 mass parts is preferable with respect to 100 mass parts of unsaturated polyester resins.

  A silicone resin has a siloxane bond (—Si—O—Si—) as a main skeleton as a resin binding component, an organic group such as a methyl group or a phenyl group, a hydroxyl group, an alkoxy group, or the like in the side chain or main chain Si atom. It contains an organopolysiloxane bonded with a curing reactive functional group. Such a silicone resin may be modified with various resins such as an alkyd resin, an epoxy resin, a phenol resin, an acrylic resin, and a melamine resin. When using such a silicone-based resin as a paint, for example, monoalkyltrichlorosilane such as monomethyltrichlorosilane and monoethyltrichlorosilane is reacted with dimethyldichlorosilane, diethyldichlorosilane and the like, and further cured. An initial condensate obtained by reacting a chlorosilane containing a curing reactive functional group containing a hydroxyl group or an alkoxy group as a reactive functional group is dissolved in a solvent, and a water repellent such as liquid paraffin or silicone oil is dissolved therein. May be blended.

  In addition, a hydrolyzable group (eg, acetoxy group, oxime group, ketoxy group, ketosim group, etc.) is introduced (bonded) in advance to such a silicone-based resin, and a polyfunctional silane compound is cross-linked with a crosslinking agent. When the hydrolyzable silicone resin in the coating material is reacted with the polyfunctional silane compound using a metal organic acid salt as a curing catalyst, it can be cured at room temperature or under heating.

  Examples of the polyfunctional silane compound as the crosslinking agent include methyl-triacetoxysilane, methyl-trimethoxysilane, methyl-tri (cyclohexylamino) silane, tri (methyl-methoxycarbonylamino) methylsilane, cyclic aminoxysiloxane, and the like. Is mentioned. Examples of the metal organic acid salt as the curing catalyst include dibutyltin dilaurate, tin dioctenoate, iron stearate, lead octylate, peroxide, organic amine and the like.

  The fluororesin is a polymer or copolymer of tetra- or trifluoro (monochloro) ethylene, and can be used as a baking type or a room-temperature curing type by taking its degree of polymerization or various copolymers.

  Phenol resins are classified into a novolac type in which phenol and formalin are bonded using an acid catalyst, and a resol type using an alkali catalyst. The novolak type is thermoplastic and can be used as an evaporative dry paint, and the resol type has a large thermosetting property and can be used as a thermosetting paint.

  Nitrocellulose can be added as an additive to the above-mentioned various binder resins as a main binder resin or for improving workability such as quick drying.

(solvent)
The solvent used in the present invention is used for securing fluidity as a paint, and a solvent used in a known general paint can be applied.
Specifically, for example, chain hydrocarbons such as neopentane, n-hexane, n-heptane and solvesso, aromatic hydrocarbons such as toluene and xylene, halogenated hydrocarbons such as trichloroethylene and perchloroethylene, methanol, ethanol, Alcohols such as isopropanol and n-butanol, ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone, esters such as ethyl acetate and n-butyl acetate, ethers such as cellosolve, butylsolve and cellosolve acetate, mineral spirits (hydrocarbons) Oil).
In addition, the said solvent may use together 1 type individually or 2 or more types by arbitrary combinations and ratios.

In addition to the above essential material, various additives may be added to the present invention.
Various additives are added for the purpose of adjusting the viscosity of the paint, improving the leveling property of the coating film, matting the surface of the coating film, adjusting the black color tone, preventing mold and rust. For example, as a viscosity adjustment, a thickener such as bentonite, silica fine particles, silicone elastomer, thickening polysaccharide, glycols, or a diluent solvent is added. Silane coupling agent, silicone coupling agent, aluminate coupling agent, titanate coupling agent, etc. for improving adhesion of the coating film to the substrate. Leveling agents such as silicone oils and surfactants are used to improve the leveling properties of the coating film, and resin particles, glass powder, quartz powder and silica powder of about 0.1 to 20 μm are used for matting the coating film surface. Etc. are added. In order to adjust the color tone of the black paint, a coloring dye or a coloring pigment is added as a complementary color. An anti-fungal agent is added to the anti-mold, and an anti-rust agent is added to the anti-rust.

(Manufacturing method of paint)
As a method for producing the antireflection black paint for optical elements of the present invention, a general method for producing a pigment-dispersed paint can be applied. For example, a portion of titanium dioxide, carbon black, binder resin, dispersant, and solvent are weighed in a stainless steel tank and thoroughly stirred and mixed with a three-one motor (premix). It is transferred to a tank connected to the machine and circulated and dispersed by a bead mill. During the dispersion of the slurry, sampling is performed as appropriate, and haze, gloss, particle size distribution and the like are used as indices of the degree of dispersion of titanium dioxide and carbon black to achieve the desired degree of dispersion. The remaining slurry of the binder resin and the remainder of the solvent are added to the obtained slurry, and various additives are added as necessary to obtain the inner surface antireflection black paint for optical elements of the present invention.

  Here, when the binder resin to be used is a two-part curable resin, for example, if it is a two-part curable epoxy resin, a curing agent such as amines and acid anhydrides is blended and stirred immediately before application to the optical element. use.

  Here, examples of the wet media disperser include a ball mill, a paint shaker, a basket mill, a dyno mill, an ultra visco mill, and an annular disperser.

  The media used in the wet media disperser are preferably materials such as alumina, zirconia, steel, and glass, and the media diameter is preferably 0.1 to 5.0 mm.

  In addition, since the paint of the present invention is a co-dispersion system of titanium dioxide and carbon black, aiming at further stabilization as a paint, both pigments are dispersed to an optimum dispersion degree, and then mixed to be mixed. Alternatively, the following method may be used.

Hereinafter, the present invention will be described in more detail with reference to examples.
The following materials were used in the following examples and comparative examples.

O Titanium dioxide / titanium dioxide A: Surface-treated titanium dioxide produced in Production Example 1 below. The average primary particle diameter was 21 nm, the hydrophobization degree of methanol was 57%, the solid content was 99% by mass, and the pH of this titanium dioxide was 6.5. The measuring method of pH is as follows. Add 5.0 g of titanium dioxide into a wide-mouth glass bottle containing 50 g of ion-exchanged water and 5 g of ethanol, and boil on a hot plate for 2 minutes. Cooled to room temperature, measured with a glass electrode pH meter after stirring and adding ion-exchanged water for the boiling loss.

[Production Example 1 (Production of Titanium Dioxide A)]
1) Production of surface untreated titanium dioxide:
(I) Dilution step: 10 kg of deionized water is added to a stainless steel 20 liter jacketed stirring tank connected to a chiller, and the inside of the tank is maintained at 5 to 10 ° C. with the rotating speed of the stirrer set to 300 rpm. In this state, 500 g of titanium tetrachloride (content 98%) was added, and the mixture was stirred and mixed for 2 hours. The solution became clear and dissolution of titanium tetrachloride was confirmed.
(Ii) Neutralization step: The number of revolutions of the stirrer was set to 600 rpm, and 20% aqueous ammonia was added at a rate of 5 g / min, and a white precipitate was generated while observing the pH change of the solution. When the pH reached 7.0, the ammonia water addition was terminated.
(Iii) Washing step (1): This solution is filtered with a vacuum filter, and then a 200 liter washing tank into which 100 parts by mass of distilled water has been put in advance in order to wash the white filter cake (containing titanium hydroxide) Then, the rotation speed of the propeller stirrer was set to 300 rpm, the mixture was stirred for 2 hours, vacuum filtered again, and this washing operation was repeated three times.
(Iv) Shape conversion step: The filter cake after washing three times is put into a 40 liter tank in which 20 parts by mass of deionized water has been put in advance, the rotation speed of the propeller stirrer is set to 300 rpm, and the mixture is stirred and mixed for 1 hour. Then, 0.05 part by mass of perchloric acid was added and further stirred for 30 minutes. The tank was heated with a band heater while stirring, and stirred for 6 hours with the temperature of the solution raised to 80 to 90 ° C., then cooled, and then added with 20% aqueous ammonia to adjust the pH of the solution. When the value reached 7.0, the addition of aqueous ammonia was terminated.
(V) Washing step (2): After this solution is filtered with a vacuum filter, in order to wash a white filter cake (high purity titanium dioxide), a 200 liter washing solution in which 100 parts by mass of distilled water has been previously added. It put into the tank, the rotation speed of the propeller stirrer was set to 300 rpm, it stirred for 2 hours, vacuum filtration was performed again, and this washing | cleaning operation was repeated 3 times.
(Vi) Dry pulverization step: The filter cake after washing three times is put into a dryer at 110 ° C. and dried, and after cooling to room temperature, the dried aggregates of titanium dioxide are crushed by the pulverizer to obtain average primary particles. A titanium dioxide having a diameter of 21 nm and an untreated surface was obtained.

2) Surface treatment of titanium dioxide:
Particles do not coalesce while stirring 10 parts by mass of surface-treated titanium dioxide obtained above and 0.9 parts by mass of isobutyltrimethoxysilane at a rotation speed of 600 rpm of a propeller in a stainless steel tank containing 100 parts by mass of toluene. And stirring was continued for 3 hours. This solution was passed through a vacuum filter, and the filter cake was dried with a 110 ° C. dryer, then cooled to room temperature and pulverized with a pulverizer to obtain surface-treated titanium dioxide A.

Titanium dioxide B: Titanium dioxide B was obtained in the same manner as in “2) Surface treatment of titanium dioxide” in Production Example 1 except that isobutyltrimethoxysilane was replaced with 0.6 parts by mass. The physical properties were an average primary particle diameter of 21 nm, a degree of hydrophobicity of methanol of 31%, a solid content of 98% by mass, and the pH of this titanium dioxide was 6.4.

Titanium dioxide C: Titanium dioxide C was obtained in the same manner as in “2) Surface treatment of titanium dioxide” in Production Example 1 except that 1.8 parts by mass of isobutyltrimethoxysilane was replaced. The physical properties were an average primary particle diameter of 21 nm, a degree of methanol hydrophobicity of 78%, a solid content of 99% by mass, and the pH of this titanium dioxide was 7.2.

Titanium dioxide D: The same operation as in Production Example 1 “1) Production of surface untreated titanium dioxide” except that the pH adjustment values in the neutralization step and the shape conversion step were replaced with 2.8. Titanium D was obtained. The physical properties were an average primary particle diameter of 21 nm, a degree of methanol hydrophobization of 58%, a solid content of 98% by mass, and the pH of this titanium dioxide was 3.0.

Titanium dioxide E: The same operation as in Production Example 1 “1) Production of surface untreated titanium dioxide” except that the pH adjustment values in the neutralization step and the shape conversion step were replaced with 8.5. Titanium E was obtained. The physical properties were an average primary particle size of 21 nm, a degree of methanol hydrophobization of 60%, a solid content of 99% by mass, and the pH of this titanium dioxide was 8.0.

Titanium dioxide F: Surface-treated titanium dioxide produced in Production Example 2 below. The average primary particle size was 7 nm, the degree of hydrophobicity of methanol was 66%, the solid content was 98% by mass, and the pH of this titanium dioxide was 6.4.

[Production Example 2 (Production of Titanium Dioxide F)]
In a stainless steel tank containing 100 parts by mass of toluene, 10 parts by mass of titanium dioxide “ST-01” (trade name, manufactured by Ishihara Sangyo Co., Ltd.) having an average primary particle diameter of 7 nm and 0.9 parts by mass of isobutyltrimethoxysilane were added to a propeller stirrer. While stirring at a rotation speed of 600 rpm, particles were added so as not to coalesce, and stirring was continued for 3 hours. This solution was passed through a vacuum filter, and the filter cake was dried with a 110 ° C. dryer, then cooled to room temperature and pulverized with a pulverizer to obtain surface-treated titanium dioxide F.

Titanium dioxide G: The same operation as in Production Example 2 except that titanium dioxide “ST-01” was replaced with titanium dioxide “MT-600B” (trade name, manufactured by Teika Co., Ltd.) having an average primary particle diameter of 50 nm. And titanium dioxide G was obtained. The physical properties were an average primary particle size of 50 nm, a degree of methanol hydrophobicity of 52%, a solid content of 99% by mass, and the pH of this titanium dioxide was 6.7.

Titanium dioxide H: Titanium dioxide H was the surface untreated titanium dioxide that was not subjected to “2) surface treatment of titanium dioxide” in Production Example 1. The physical properties were an average primary particle size of 21 nm, a degree of hydrophobicity of methanol of 0%, a solid content of 97% by mass, and the pH of this titanium dioxide was 6.9.

Titanium dioxide I: The same operation as in Production Example 1 “1) Production of surface untreated titanium dioxide” except that the pH adjustment values in the neutralization step and the shape conversion step were replaced with 10.0. Titanium I was obtained. The physical properties were an average primary particle diameter of 21 nm, a degree of methanol hydrophobization of 41%, a solid content of 98% by mass, and the pH of this titanium dioxide was 8.6.

Carbon black / carbon black A: Mitsubishi carbon black MA100 (trade name, manufactured by Mitsubishi Chemical Corporation). The average primary particle size was 24 nm, the DBP absorption was 100 ml / 100 g, the volatile content was 1.5 mass%, the solid content was 97 mass%, and the pH of this carbon black was 6.0. The pH value was measured by the same method as the pH measurement of titanium dioxide.

Carbon black B: Mitsubishi carbon black # 40 (trade name, manufactured by Mitsubishi Chemical Corporation). The average primary particle diameter was 24 nm, the DBP absorption was 110 ml / 100 g, the volatile content was 0.8 mass%, the solid content was 97 mass%, and the pH of this carbon black was 7.5.

Carbon black C: Mitsubishi carbon black MA200RB (trade name, manufactured by Mitsubishi Chemical Corporation). The average primary particle size was 30 nm, the DBP absorption was 91 ml / 100 g, the volatile content was 5.5% by mass, the solid content was 96% by mass, and the pH of this carbon black was 3.0.

Carbon black D: Mitsubishi carbon black MA8 (trade name, manufactured by Mitsubishi Chemical Corporation). The average primary particle size was 24 nm, the DBP absorption amount was 51 ml / 100 g, the volatile content was 3.0% by mass, the solid content was 97% by mass, and the pH of this carbon black was 3.0.

Carbon black E: Mitsubishi carbon black # 52 (trade name, manufactured by Mitsubishi Chemical Corporation). The average primary particle diameter was 27 nm, the DBP absorption was 63 ml / 100 g, the volatile content was 0.8 mass%, the solid content was 98 mass%, and the pH of this carbon black was 8.0.

Carbon Black F: Talker Black # 7050 (trade name, manufactured by Tokai Carbon Co., Ltd.). The average primary particle diameter was 66 nm, the DBP absorption was 66 ml / 100 g, the volatile content was 1.0 mass%, the solid content was 97 mass%, and the pH of this carbon black was 8.0.

Carbon black H: SUNBLACK240 (trade name, manufactured by Asahi Carbon Co., Ltd.). The average primary particle size was 80 nm, the DBP absorption was 63 ml / 100 g, the volatile content was 0.7 mass%, the solid content was 97 mass%, and the pH of this carbon black was 7.5.

Carbon black I: Mitsubishi carbon black # 45 (trade name, manufactured by Mitsubishi Chemical Corporation). The average primary particle diameter was 24 nm, the DBP absorption amount was 46 ml / 100 g, the volatile content was 0.8 mass%, the solid content was 98 mass%, and the pH of this carbon black was 8.0.

Carbon black J: Mitsubishi carbon black # 3350B (trade name, manufactured by Mitsubishi Chemical Corporation). The average primary particle diameter was 24 nm, the DBP absorption was 165 ml / 100 g, the volatile content was 1.4 mass%, the solid content was 97 mass%, and the pH of this carbon black was 7.0.

Carbon black K: Mitsubishi carbon black # 2350 (trade name, manufactured by Mitsubishi Chemical Corporation). The average primary particle diameter was 13 nm, the DBP absorption was 73 ml / 100 g, the volatile content was 7.5% by mass, the solid content was 96% by mass, and the pH of this carbon black was 3.0.

Carbon black L: Mitsubishi carbon black # 4000B (trade name, manufactured by Mitsubishi Chemical Corporation). The average primary particle diameter was 20 nm, the DBP absorption was 102 ml / 100 g, the volatile content was 0.3 mass%, the solid content was 98 mass%, and the pH of this carbon black was 10.0.

○ Phthalocyanine compound / dispersant A: Copper phthalocyanine derivative “EFKA-6745” (trade name, manufactured by BASF Japan Ltd.), pH 4.5. This pH value was measured by the same method as the pH measurement of titanium dioxide.
Dispersant B: Copper phthalocyanine derivative “SOLSPERSE 5000” (trade name, manufactured by Nippon Lubrizol Corporation), pH 3.8.
Dispersant C: Copper phthalocyanine sulfonic acid derivative “VALIFAST BLUE2670” (trade name, manufactured by Orient Chemical Industries, Ltd.), pH 7.7.

Polymer dispersing agent / dispersing agent D: Polymer dispersing agent solution “SOLSPERSE24000SC” (trade name, manufactured by Nippon Lubrizol Co., Ltd., active ingredient 100 mass%, amine value 42 mg KOH / g) methyl isobutyl ketone in advance A solution with a concentration of 40% by mass dissolved in
Dispersant E: Polymeric dispersant “KF-1500” (trade name, manufactured by Kawaken Fine Chemical Co., Ltd.), active ingredient 100 mass%, amine value 7 mg KOH / g.
Dispersant F: Polymeric dispersant solution “EFKA-4401” (trade name, manufactured by BASF Japan Ltd.), active ingredient 50% by mass, amine value 50 mg KOH / g (= amine value for active ingredient is 100 mg KOH / g) .
Dispersant G: Polymeric dispersant solution “PA-111” (trade name, manufactured by Ajinomoto Fine Techno Co., Ltd.), amine value 0 mg KOH / g

Binder resin component / isocyanate A: HDI isocyanurate “Duranate TPA-100” (trade name, manufactured by Asahi Kasei Chemicals Corporation), NCO content of 23.1% by mass to 40% by mass with methyl isobutyl ketone Diluted mixed solution.
Isocyanate B: isocyanurate of HDI, methyl ethyl ketoxime block product “Duranate TPA-B80E” (trade name, manufactured by Asahi Kasei Chemicals Corporation), NCO content 12.5% by mass.

[Example 1]
(Preparation of internal antireflection black paint)
The following materials were weighed in a stainless steel tank and stirred and mixed with a propeller stirrer for 12 hours to obtain a mill base.
-Titanium dioxide A: 2.500 parts by mass-Carbon black A: 0.284 parts by mass-Modified polycarbonate diol ("Nipporan 983" trade name, manufactured by Nippon Polyurethane Industry Co., Ltd., OH value 115 mgKOH / g): 1.550 parts by mass Part / Dispersant A: 0.014 parts by mass Dispersant D: 1.375 parts by mass Methyl isobutyl ketone: 2.219 parts by mass For this mill base, the media (glass beads having an average particle size of 0.8 mm) were One-pass dispersion was performed using a wet media disperser (Ultraviscomil (trade name), manufactured by Imex Co., Ltd.) filled at a filling rate of 80% by volume. The processing conditions were a disk peripheral speed of 6 m / s and a processing speed of 200 ml / min.

  The mill base that had been subjected to the one-pass dispersion treatment was transferred to a stainless steel circulation tank, and the dispersion was carried out for 12 hours at a disk peripheral speed of 6 m / s and a treatment speed of 200 ml / min. The peripheral speed was changed to 3 m / s, the processing speed was 400 ml / min, 1.000 parts by mass of methyl isobutyl ketone was added, and the dispersion was further performed for 1 hour to prepare the base material of the paint A.

8.94 parts by mass of the main component of the paint A and 1.06 parts by mass of isocyanate A were placed in a container and stirred and mixed for 1 minute while being careful not to cause excessive foam with a disper.
A small amount of this mixed solution is sampled, the viscosity at 23 ° C. is measured with an E-type viscometer, and 1.00 parts by mass of methyl isobutyl ketone is added and diluted so that the viscosity value is within 30 to 60 mPa · s. When stirring and measurement of the viscosity value were repeated, when 2.00 parts by mass of methyl isobutyl ketone was added, the viscosity value became 32.5 mPa · s, and the dilution was completed. This value was defined as the initial viscosity value (M) mPa · s. .
The contents of titanium dioxide and carbon black in the solid content of the paint were determined using the above “Formula 1” and found to be 45.2% by mass and 5.1% by mass, respectively.

[Various evaluations]
(Preparation of internal reflectance evaluation sample)
The coating material A obtained above was set on a rotating table of a spin coater so that the bottom surface of the evaluation triangle was horizontal and the bottom surface was horizontal, and the entire bottom surface was spin coated so as to spread to a uniform film thickness. This was dried at room temperature for 30 minutes and then cured at 140 ° C. for 1 hour in an electric furnace to obtain a sample for evaluating internal reflectance as shown in FIG. The thickness of the coating film was adjusted to be 10 μm or more so that the transparency of the coating film was lost. As the right triangle prism, S-LAH53 (manufactured by OHARA INC., Nd = 1.81) was used. As for the size of this right triangle prism, the length of two sides sandwiching the right angle was set to 30 mm. All surfaces of this right triangle prism were polished into mirror surfaces.

<Measurement method of internal reflectance>
As shown in FIG. 3, when the triangular prism 5 having the coating film 2 formed in the spectrophotometer is installed in the sample installation section and the incident light 7 is passed from the light source 6, the coating film is refracted into the prism at an incident angle θ. 2 and the internal reflection light 8 is emitted. The inner surface reflected light 8 is received by an integrating sphere and a photodetector 9, and the intensity of light at each wavelength is measured.
For the uncoated triangular prism 5 not provided with the coating film 2, the inner surface reflected light intensity with respect to light having a wavelength of 400 to 700 nm is measured in advance at an interval of 5 nm, and the light intensity at each wavelength is set to an inner surface reflectance of 100%. . Then, the inner surface reflected light intensity with respect to light having a wavelength of 400 to 700 nm measured at intervals of 5 nm was converted into% for the inner surface reflectance measurement sample (coated triangular prism) prepared above, and the arithmetic average value of the result was taken. And the inner surface reflectance (L) of the sample.

(Evaluation of storage stability of paint over time)
The base material of the paint A prepared above was sealed in a glass bottle and stored for 30 days in a 10 ° C. environment. The main component of paint A, isocyanate A and methyl ethyl ketone were mixed at the same mass part ratio when the main component of paint A, which was stored over time, was stirred for 1 minute on a paint shaker and blended and prepared in the above-mentioned “Preparation of Internal Antireflection Black Paint”. In the container, care was taken to avoid excessive foaming with the disperser, and the storage viscosity over time (N) mPa · s was measured.
Then, the storage stability of the paint over time was evaluated by the following formula.
“Thickening rate of paint over time (%)” = (N) / (M) × 100
The “viscosity thickening ratio (%) of paint over time” is most stable when it is 1, and can be regarded as being less stable as it becomes larger than 1. Also, if it is smaller than 1, it can be considered that the stability is poor.

(Evaluation of coating workability of paint over time)
In the above “Evaluation of storage stability of paint over time”, 0.1 g of the paint used for the measurement of storage viscosity over time is dropped on an aluminum dish, washed with acetone in advance and dried to create a brush (HC-9000 series Dip into the tip of a flat brush 3/8 inch, manufactured by Handy Crown Co., Ltd.) and blend in evenly. One side of the slide glass (water edge polished frost, 76 x 26 mm, thickness 0.9 to 1.2 mm, frost width 15 x 26 mm, manufactured by Matsunami Glass Industrial Co., Ltd.), the surface of which has been washed with acetone in advance, is removed. The coating was performed over a period of time (23 ± 3 ° C., 53 ± 10% RH environment), and the degree of occurrence of coating unevenness was visually evaluated in the following three stages.
○: The entire slide glass can be applied smoothly and there is almost no coating irregularity. △: The entire slide glass could be applied, but coating unevenness occurred. ×: The entire slide glass could not be applied, and coating The above-mentioned various evaluation results are shown in Table 1.

[Example 2]
In Example 1 "Preparation of black paint for preventing internal reflection", except that Titanium dioxide A introduced at the time of mill base preparation was replaced with 2.526 parts by mass of titanium dioxide B and 2.193 parts by mass of methyl isobutyl ketone. In the same manner as in Example 1, a main component of Paint B was obtained.
8.94 parts by mass of the main component of paint B and 1.06 parts by mass of isocyanate A were placed in a container and stirred, and diluted with methyl isobutyl ketone in the same manner as in Example 1 to obtain paint B. The initial viscosity value of the paint B was 35.8 mPa · s, and the contents of titanium dioxide and carbon black in the solid content of the paint were 45.1% by mass and 5.0% by mass, respectively.
[Various evaluations]
The obtained paint was subjected to various evaluations in the same manner as in Example 1. Various evaluation results are shown in Table 1.

Example 3
A main component of paint C was obtained in the same manner as in Example 1 except that in preparation of the black paint for preventing internal reflection in Example 1, titanium dioxide A to be added at the time of mill base preparation was replaced with titanium dioxide C.
A main component of this paint C, 8.94 parts by mass and 1.06 parts by mass of isocyanate A, were placed in a container and stirred, and diluted with methyl isobutyl ketone in the same manner as in Example 1 to obtain paint C. The initial viscosity value of the paint C was 40.3 mPa · s, and the contents of titanium dioxide and carbon black in the solid content of the paint were 45.2% by mass and 5.0% by mass, respectively.
[Various evaluations]
The obtained paint was subjected to various evaluations in the same manner as in Example 1. Various evaluation results are shown in Table 1.

Example 4
In Example 1 “Preparation of black anti-reflective coating”, except that titanium dioxide A to be added at the time of mill base preparation was replaced with 2.526 parts by mass of titanium dioxide D and 2.193 parts by mass of methyl isobutyl ketone. In the same manner as in Example 1, the main component of Paint D was obtained.
The main component of this paint D, 8.94 parts by mass and 1.06 parts by mass of isocyanate A, were placed in a container and stirred, and diluted with methyl isobutyl ketone in the same manner as in Example 1 to obtain paint D. The initial viscosity value of the paint D was 50.2 mPa · s, and the contents of titanium dioxide and carbon black in the paint solid content were 45.2% by mass and 5.0% by mass, respectively.
[Various evaluations]
The obtained paint was subjected to various evaluations in the same manner as in Example 1. Various evaluation results are shown in Table 1.

Example 5
A main component of paint E was obtained in the same manner as in Example 1 except that in preparation of black antireflective coating for internal reflection in Example 1, titanium dioxide A introduced during mill base preparation was replaced with titanium dioxide E.
8.94 parts by mass of the main component of paint E and 1.06 parts by mass of isocyanate A were placed in a container and stirred, and diluted with methyl isobutyl ketone in the same manner as in Example 1 to obtain paint E. The initial viscosity value of the paint E was 45.0 mPa · s, and the contents of titanium dioxide and carbon black in the solid content of the paint were 45.2% by mass and 5.1% by mass, respectively.

Example 6
In "Preparation of black paint for preventing internal reflection" in Example 1, 1.667 parts by mass of titanium dioxide A to be added at the time of mill base preparation, 2.253 parts by mass of Nipponran 983, 0.963 parts by mass of dispersant D, methyl A base material of the paint F was obtained in the same manner as in Example 1 except that 2.282 parts by mass of isobutyl ketone was replaced.
8.46 parts by mass of the main component of the paint F and 1.54 parts by mass of isocyanate A were placed in a container and stirred, and diluted with methyl isobutyl ketone in the same manner as in Example 1 to obtain paint F. The initial viscosity value of the paint F was 36.3 mPa · s, and the contents of titanium dioxide and carbon black in the solid content of the paint were 35.1% by mass and 5.0% by mass, respectively.
[Various evaluations]
The obtained paint was subjected to various evaluations in the same manner as in Example 1. Various evaluation results are shown in Table 1.

Example 7
In "Preparation of black paint for preventing internal reflection" in Example 1, 3.889 parts by mass of titanium dioxide A, 0.419 parts by mass of Nipporan 983, and 1.925 parts by mass of dispersant D, which are added when preparing the mill base A main component of the paint G was obtained in the same manner as in Example 1 except that 2.184 parts by mass of isobutyl ketone was replaced.
9.71 parts by mass of the main component of this paint G and 0.29 parts by mass of isocyanate A were placed in a container and stirred, and diluted with methyl isobutyl ketone in the same manner as in Example 1 to obtain paint G. The initial viscosity value of the paint G was 39.1 mPa · s, and the contents of titanium dioxide and carbon black in the solid content of the paint were 75.0% by mass and 5.0% by mass, respectively.
[Various evaluations]
The obtained paint was subjected to various evaluations in the same manner as in Example 1. Various evaluation results are shown in Table 1.

Example 8
A base material of paint H was obtained in the same manner as in Example 1 except that in the “preparation of black paint for internal reflection prevention” in Example 1, carbon black A to be added at the time of mill base preparation was replaced with carbon black B.
The main component of this paint H, 8.94 parts by mass and 1.06 parts by mass of isocyanate A, were placed in a container and stirred, and diluted with methyl isobutyl ketone in the same manner as in Example 1 to obtain paint H. The initial viscosity value of the paint H was 42.0 mPa · s, and the contents of titanium dioxide and carbon black in the solid content of the paint were 45.1% by mass and 5.0% by mass, respectively.
[Various evaluations]
The obtained paint was subjected to various evaluations in the same manner as in Example 1. Various evaluation results are shown in Table 1.

Example 9
In the “preparation of black antireflection coating for inner surface” in Example 1, except that the carbon black A introduced at the time of mill base preparation was replaced with 0.287 parts by mass of carbon black C and methyl isobutyl ketone was replaced with 2.216 parts by mass. In the same manner as in Example 1, the main component of Paint I was obtained.
8.94 parts by weight of the main component of Paint I and 1.06 parts by weight of Isocyanate A were placed in a container and stirred, and diluted with methyl isobutyl ketone in the same manner as in Example 1 to obtain Paint I. The initial viscosity value of the paint I was 50.3 mPa · s, and the contents of titanium dioxide and carbon black in the solid content of the paint were 45.2% by mass and 5.1% by mass, respectively.
[Various evaluations]
The obtained paint was subjected to various evaluations in the same manner as in Example 1. Various evaluation results are shown in Table 1.

Example 10
The main component of paint J was obtained in the same manner as in Example 1 except that in the “preparation of black paint for preventing internal reflection” in Example 1, the carbon black A introduced during mill base preparation was changed to carbon black D.
The main component of this paint J, 8.94 parts by mass and 1.06 parts by mass of isocyanate A, were placed in a container and stirred, and diluted with methyl isobutyl ketone in the same manner as in Example 1 to obtain paint J. The initial viscosity value of the paint J was 52.6 mPa · s, and the contents of titanium dioxide and carbon black in the paint solid content were 45.2% by mass and 5.1% by mass, respectively.
[Various evaluations]
The obtained paint was subjected to various evaluations in the same manner as in Example 1. Various evaluation results are shown in Table 1.

Example 11
In “Preparation of black paint for preventing internal reflection” in Example 1, 0.281 parts by mass of carbon black E, 1.361 parts by mass of Nipponran 983, and 2.439 parts by mass of methyl isobutyl ketone were added. In the same manner as in Example 1 except that 1.031 parts by mass of isocyanate B was added, a base material for paint K was obtained.
10.00 parts by mass of the main component of the paint K was placed in a container and stirred, and diluted with methyl isobutyl ketone in the same manner as in Example 1 to obtain paint K. The initial viscosity value of the paint K was 51.1 mPa · s, and the contents of titanium dioxide and carbon black in the solid content of the paint were 45.2% by mass and 5.1% by mass, respectively.
[Various evaluations]
The obtained paint was subjected to various evaluations in the same manner as in Example 1. Various evaluation results are shown in Table 1.

Example 12
In “Preparation of black paint for preventing internal reflection” in Example 1, 0.028 parts by mass of carbon black A, 1.554 parts by mass of Nippon Black 983, and 0.0014 parts by mass of Dispersant A were added at the time of mill base preparation. The main component of paint L was obtained in the same manner as in Example 1 except that 1.251 parts by mass of dispersant D and 2.488 parts by mass of methyl isobutyl ketone were added and 1.177 parts by mass of isocyanate B was added. .
10.00 parts by mass of the main component of the paint L was placed in a container and stirred, and diluted with methyl isobutyl ketone in the same manner as in Example 1 to obtain paint L. The initial viscosity value of the paint L was 39.8 mPa · s, and the contents of titanium dioxide and carbon black in the solid content of the paint were 45.1% by mass and 0.50% by mass, respectively.
[Various evaluations]
The obtained paint was subjected to various evaluations in the same manner as in Example 1. Various evaluation results are shown in Table 1.

Example 13
In “Preparation of black paint for preventing internal reflection” in Example 1, 1.134 parts by mass of carbon black A, 0.719 parts by mass of Nipporan 983, 0.055 parts by mass of dispersant A, dispersed in the mill base preparation The base material of the paint M was obtained in the same manner as in Example 1 except that the agent D was replaced with 1.788 parts by mass and 2.259 parts by mass of methyl isobutyl ketone and 0.545 parts by mass of isocyanate B was added.
10.00 parts by mass of the main component of this paint M was placed in a container and stirred, and diluted with methyl isobutyl ketone in the same manner as in Example 1 to obtain paint M. The initial viscosity value of the paint M was 40.8 mPa · s, and the contents of titanium dioxide and carbon black in the solid content of the paint were 45.2% by mass and 20.2% by mass, respectively.
[Various evaluations]
The obtained paint was subjected to various evaluations in the same manner as in Example 1. Various evaluation results are shown in Table 1.

Example 14
In “Preparation of black paint for preventing internal reflection” in Example 1, Nippon Run 983 to be added at the time of mill base preparation was acrylic resin (“Acridic A-136-55” trade name, manufactured by DIC Corporation, active ingredient 55.0 mass%. ) A base material of paint N was obtained in the same manner as in Example 1 except that 3.995 parts by mass, dispersant A was changed to 0.0028 parts by mass, and methyl isobutyl ketone 0.844 parts by mass.
10.00 parts by mass of the main component of paint N was placed in a container and stirred, and diluted with methyl isobutyl ketone in the same manner as in Example 1 to obtain paint N. The initial viscosity value of the paint N was 35.5 mPa · s, and the contents of titanium dioxide and carbon black in the solid content of the paint were 45.2% by mass and 5.0% by mass, respectively.
[Various evaluations]
The obtained paint was subjected to various evaluations in the same manner as in Example 1. Various evaluation results are shown in Table 1.

Example 15
In Example 1 "Preparation of black antireflective coating," Nippon Poly 983 to be added at the time of mill base preparation is polyester resin ("KA-2070", trade name, Arakawa Chemical Industries, Ltd., active ingredient 40.0 mass%) 5 A main component of paint O was obtained in the same manner as in Example 1, except that 363 parts by mass, 0.055 parts by mass of dispersant A, and methyl isobutyl ketone were not added.
10.00 parts by mass of the main component of this paint O was placed in a container and stirred, and diluted with methyl isobutyl ketone in the same manner as in Example 1 to obtain paint O. The initial viscosity value of the paint O was 33.6 mPa · s, and the contents of titanium dioxide and carbon black in the solid content of the paint were 45.1% by mass and 5.0% by mass, respectively.
[Various evaluations]
The obtained paint was subjected to various evaluations in the same manner as in Example 1. Various evaluation results are shown in Table 1.

Example 16
In “Preparation of black paint for preventing internal reflection” in Example 1, Nipponran 983 to be added at the time of mill base preparation was replaced with silicone resin (“TSR108” trade name, manufactured by Momentive Performance Materials Japan LLC, active ingredient 55.0 mass) %) 3.895 parts by weight, Dispersant D is replaced by 0.550 parts by weight of Dispersant E, and methyl isobutyl ketone is replaced by 1.421 parts by weight, coin catalyst ("CR12" trade name, Momentive Performance Materials Japan) A main component of paint P was obtained in the same manner as in Example 1 except that 0.336 parts by mass of an active ingredient (13.0% by mass, manufactured by Godo Kaisha) was added.
10.00 parts by mass of the main component of this paint P was placed in a container and stirred, and diluted with methyl isobutyl ketone in the same manner as in Example 1 to obtain paint P. The initial viscosity value of the paint P was 50.2 mPa · s, and the contents of titanium dioxide and carbon black in the solid content of the paint were 45.1% by mass and 5.0% by mass, respectively.
[Various evaluations]
The obtained paint was subjected to various evaluations in the same manner as in Example 1. Various evaluation results are shown in Table 1.

Example 17
In “Preparation of black paint for preventing internal reflection” in Example 1, 1.457 parts by weight of the epoxy resin (“jER828”, trade name, manufactured by Mitsubishi Chemical Corporation, epoxy equivalent 190) of Nippon Run 983 to be added at the time of mill base preparation, dispersant A base material for paint Q was obtained in the same manner as in Example 1, except that D was replaced with 1.100 parts by mass of dispersant F and 1.421 parts by mass of methyl isobutyl ketone.
9.271 parts by mass of the main component of the paint Q and 0.729 parts by mass of an epoxy curing agent (“Dytoclar D-677” trade name, manufactured by Daito Sangyo Co., Ltd., active hydrogen equivalent 94.4) were placed in a container and stirred. In the same manner as in Example 1, it was diluted with methyl isobutyl ketone to obtain paint Q. The initial viscosity value of the paint Q was 51.3 mPa · s, and the contents of titanium dioxide and carbon black in the paint solid content were 45.2% by mass and 5.1% by mass, respectively.
[Various evaluations]
The obtained paint was subjected to various evaluations in the same manner as in Example 1. Various evaluation results are shown in Table 1.

Example 18
In “Preparation of black paint for preventing internal reflection” in Example 1, 1.43 parts by mass of Nipponran 983, 0.344 parts by mass of Dispersant D, and 2.756 parts by mass of methyl isobutyl ketone, which were added at the time of mill base preparation. Except that, the base material of the paint R was obtained in the same manner as in Example 1.
The main component of this paint R, 8.74 parts by mass and 1.26 parts by mass of isocyanate A were placed in a container and stirred, and diluted with methyl isobutyl ketone in the same manner as in Example 1 to obtain paint R. The initial viscosity value of the paint R was 45.8 mPa · s, and the contents of titanium dioxide and carbon black in the solid content of the paint were 45.2% by mass and 5.1% by mass, respectively.
[Various evaluations]
The obtained paint was subjected to various evaluations in the same manner as in Example 1. Various evaluation results are shown in Table 1.

Example 19
In “Preparation of black paint for preventing internal reflection” in Example 1, 1.160 parts by mass of Nipponran 983, 2.750 parts by mass of Dispersant D, and 1.500 parts by mass of methyl isobutyl ketone were added at the time of mill base preparation. Except that, the base material of the paint S was obtained in the same manner as in Example 1.
A main ingredient of this paint S, 9.21 parts by mass and 0.79 parts by mass of isocyanate A were placed in a container and stirred, and diluted with methyl isobutyl ketone in the same manner as in Example 1 to obtain paint S. The initial viscosity value of the paint S was 46.0 mPa · s, and the contents of titanium dioxide and carbon black in the solid content of the paint were 45.2% by mass and 5.0% by mass, respectively.
[Various evaluations]
The obtained paint was subjected to various evaluations in the same manner as in Example 1. Various evaluation results are shown in Table 1.

Example 20
In the “preparation of black paint for preventing internal reflection” in Example 1, except that titanium oxide A to be added at the time of mill base preparation was replaced with 2.526 parts by mass of titanium oxide F and 2.193 parts by mass of methyl isobutyl ketone. In the same manner as in Example 1, the main component of the paint T was obtained.
8.94 parts by weight of the main component of the paint T and 1.06 parts by weight of isocyanate A were placed in a container and stirred, and diluted with methyl isobutyl ketone in the same manner as in Example 1 to obtain paint T. The initial viscosity value of the paint T was 49.2 mPa · s, and the contents of titanium dioxide and carbon black in the solid content of the paint were 45.1% by mass and 5.0% by mass, respectively.
[Various evaluations]
The obtained paint was subjected to various evaluations in the same manner as in Example 1. Various evaluation results are shown in Table 1.

Example 21
In the “preparation of black paint for preventing internal reflection” in Example 1, except that titanium oxide A to be added at the time of mill base preparation was replaced with 2.526 parts by mass of titanium oxide G and 2.193 parts by mass of methyl isobutyl ketone. In the same manner as in Example 1, a main ingredient of paint U was obtained.
8.94 parts by mass of the main component of paint U and 1.06 parts by mass of isocyanate A were placed in a container and stirred, and diluted with methyl isobutyl ketone in the same manner as in Example 1 to obtain paint U. The initial viscosity value of the paint U was 41.5 mPa · s, and the contents of titanium dioxide and carbon black in the solid content of the paint were 45.0 mass% and 5.0 mass%, respectively.
[Various evaluations]
The obtained paint was subjected to various evaluations in the same manner as in Example 1. Various evaluation results are shown in Table 1.

[Example 22]
In Example 1 “Preparation of black paint for preventing internal reflection”, except that carbon black A to be added at the time of mill base preparation was replaced with 0.286 parts by mass of carbon black G and 2.216 parts by mass of methyl isobutyl ketone. In the same manner as in Example 1, a main ingredient of paint V was obtained.
The main component of this paint V, 8.94 parts by mass and 1.06 parts by mass of isocyanate A, were placed in a container and stirred, and diluted with methyl isobutyl ketone in the same manner as in Example 1 to obtain paint V. The initial viscosity value of the paint V was 33.9 mPa · s, and the contents of titanium dioxide and carbon black in the solid content of the paint were 45.2% by mass and 5.0% by mass, respectively.
[Various evaluations]
The obtained paint was subjected to various evaluations in the same manner as in Example 1. Various evaluation results are shown in Table 1.

Example 23
A base material of the paint W was obtained in the same manner as in Example 1 except that the carbon black A introduced in the mill base preparation was replaced with the carbon black H in “Preparation of black paint for internal reflection prevention” in Example 1.
The main component of this paint W, 8.94 parts by mass and 1.06 parts by mass of isocyanate A, were placed in a container and stirred, and diluted with methyl isobutyl ketone in the same manner as in Example 1 to obtain paint W. The initial viscosity value of the paint W was 45.4 mPa · s, and the contents of titanium dioxide and carbon black in the solid content of the paint were 45.1% by mass and 5.0% by mass, respectively.
[Various evaluations]
The obtained paint was subjected to various evaluations in the same manner as in Example 1. Various evaluation results are shown in Table 1.

Example 24
In the “preparation of black antireflection coating for inner surface” in Example 1, except that the carbon black A introduced at the time of mill base preparation was replaced with 0.281 parts by mass of carbon black I and 2.222 parts by mass of methyl isobutyl ketone. In the same manner as in Example 1, a main component of paint X was obtained.
The main component of this paint X, 8.94 parts by mass and 1.06 parts by mass of isocyanate A, were placed in a container and stirred, and diluted with methyl isobutyl ketone in the same manner as in Example 1 to obtain paint X. The initial viscosity value of the paint X was 38.7 mPa · s, and the contents of titanium dioxide and carbon black in the solid content of the paint were 45.2% by mass and 5.0% by mass, respectively.
[Various evaluations]
The obtained paint was subjected to various evaluations in the same manner as in Example 1. Various evaluation results are shown in Table 1.

Example 25
A base material of paint Y was obtained in the same manner as in Example 1 except that carbon black A introduced during mill base preparation was replaced with carbon black J in “Preparation of black paint for internal reflection prevention” in Example 1.
A main component of this paint Y, 8.94 parts by mass and 1.06 parts by mass of isocyanate A, were placed in a container and stirred, and diluted with methyl isobutyl ketone in the same manner as in Example 1 to obtain paint Y. The initial viscosity value of the paint Y was 53.2 mPa · s, and the contents of titanium dioxide and carbon black in the solid content of the paint were 45.2% by mass and 5.1% by mass, respectively.
[Various evaluations]
The obtained paint was subjected to various evaluations in the same manner as in Example 1. Various evaluation results are shown in Table 1.

Example 26
A main component of paint Z was obtained in the same manner as in Example 1, except that, in “Preparation of black paint for preventing internal reflection” in Example 1, Dispersant A used in preparing the mill base was replaced with Dispersant B.
8.94 parts by weight of the main component of paint Z and 1.06 parts by weight of isocyanate A were placed in a container and stirred, and diluted with methyl isobutyl ketone in the same manner as in Example 1 to obtain paint Z. The initial viscosity value of the paint Z was 55.8 mPa · s, and the contents of titanium dioxide and carbon black in the solid content of the paint were 45.2% by mass and 5.0% by mass, respectively.
[Various evaluations]
The obtained paint was subjected to various evaluations in the same manner as in Example 1. Various evaluation results are shown in Table 1.

Example 27
In the “Preparation of black paint for preventing internal reflection” in Example 1, the main component of Paint A was obtained in the same manner as in Example 1 except that Dispersant A added during mill base preparation was replaced with Dispersant C.
8.94 parts by weight of the main component of Paint A and 1.06 parts by weight of isocyanate A were placed in a container and stirred, and diluted with methyl isobutyl ketone in the same manner as in Example 1 to obtain Paint A. The initial viscosity value of this paint A was 57.7 mPa · s, and the contents of titanium dioxide and carbon black in the solid content of the paint were 45.2% by mass and 5.0% by mass, respectively.
[Various evaluations]
The obtained paint was subjected to various evaluations in the same manner as in Example 1. Various evaluation results are shown in Table 1.

[Comparative Example 1]
In Example 1 "Preparation of black paint for preventing internal reflection", except that the titanium oxide A to be added at the time of mill base preparation was replaced with 2.552 parts by mass of titanium oxide H and 2.167 parts by mass of methyl isobutyl ketone. In the same manner as in No. 1, a base material for paint b was obtained.
8.94 parts by mass of the main component of paint B and 1.06 parts by mass of isocyanate A were placed in a container and stirred, and diluted with methyl isobutyl ketone in the same manner as in Example 1 to obtain paint B. The initial viscosity value of this paint was 38.2 mPa · s, and the contents of titanium dioxide and carbon black in the paint solids were 45.1 mass% and 5.0 mass%, respectively.
[Various evaluations]
The obtained paint was subjected to various evaluations in the same manner as in Example 1. Various evaluation results are shown in Table 1.

[Comparative Example 2]
In Example 1 "Preparation of black paint for preventing internal reflection", except that titanium oxide A to be added at the time of mill base preparation was replaced with 2.526 parts by mass of titanium oxide I and 2.193 parts by mass of methyl isobutyl ketone. In the same manner as in No. 1, a main component of paint C was obtained.
8.94 parts by mass of the main component of the coating material C and 1.06 parts by mass of isocyanate A were placed in a container and stirred, and diluted with methyl isobutyl ketone in the same manner as in Example 1 to obtain coating material C. The initial viscosity value of the coating material C was 35.6 mPa · s, and the contents of titanium dioxide and carbon black in the solid content of the coating material were 45.1% by mass and 5.0% by mass, respectively.
[Various evaluations]
The obtained paint was subjected to various evaluations in the same manner as in Example 1. Various evaluation results are shown in Table 1.

[Comparative Example 3]
In "Preparation of black paint for preventing internal reflection" in Example 1, 1.389 parts by mass of titanium oxide A, 2.487 parts by mass of Nipponran 983, 0.825 parts by mass of dispersant D, A base material for paint D was obtained in the same manner as in Example 1 except that the amount was replaced with 2.303 parts by mass of isobutyl ketone.
8.30 parts by mass of the main component of the coating material D and 1.70 parts by mass of isocyanate A were placed in a container and stirred, and diluted with methyl isobutyl ketone in the same manner as in Example 1 to obtain coating material D. The initial viscosity value of this paint D was 45.8 mPa · s, and the contents of titanium dioxide and carbon black in the paint solids were 25.0 mass% and 5.0 mass%, respectively.
[Various evaluations]
The obtained paint was subjected to various evaluations in the same manner as in Example 1. Various evaluation results are shown in Table 1.

[Comparative Example 4]
In Example 1 “Preparation of black paint for preventing internal reflection”, except that carbon black A introduced at the time of mill base preparation was replaced with 0.286 parts by mass of carbon black K and 2.216 parts by mass of methyl isobutyl ketone. In the same manner as in No. 1, a main component of paint ho was obtained.
8.94 parts by mass of the main component of this paint ho and 1.06 parts by mass of isocyanate A were placed in a container and stirred, and diluted with methyl isobutyl ketone in the same manner as in Example 1 to obtain paint ho. The initial viscosity value of the paint ho was 48.3 mPa · s, and the contents of titanium dioxide and carbon black in the solid content of the paint were 45.2% by mass and 5.0% by mass, respectively.
[Various evaluations]
The obtained paint was subjected to various evaluations in the same manner as in Example 1. Various evaluation results are shown in Table 1.

[Comparative Example 5]
Example 1 except that in the “preparation of black paint for preventing internal reflection” in Example 1, the carbon black A introduced during mill base preparation was replaced with 0.281 parts by mass of carbon black L and 2.222 parts by mass of methyl isobutyl ketone. In the same manner as in No. 1, a main agent for paint was obtained.
8.94 parts by mass of the main agent for this paint and 1.06 parts by mass of isocyanate A were placed in a container and stirred, and diluted with methyl isobutyl ketone in the same manner as in Example 1 to obtain a paint. The initial viscosity value of this paint was 50.1 mPa · s, and the contents of titanium dioxide and carbon black in the paint solids were 45.2% by mass and 5.1% by mass, respectively.
[Various evaluations]
The obtained paint was subjected to various evaluations in the same manner as in Example 1. Various evaluation results are shown in Table 1.

[Comparative Example 6]
In Example 1 “Preparation of black antireflective coating,” dispersant A added at the time of mill base preparation was not added, and Nipponran 983 was replaced with 1.560 parts by mass and 2.215 parts by mass of methyl isobutyl ketone. Was the same as in Example 1 to obtain the main component of the paint.
8.93 parts by mass of the main agent for this paint and 1.07 parts by mass of isocyanate A were placed in a container and stirred, and diluted with methyl isobutyl ketone in the same manner as in Example 1 to obtain a paint. The initial viscosity value of this paint was 48.2 mPa · s, and the contents of titanium dioxide and carbon black in the paint solids were 45.1% by mass and 5.0% by mass, respectively.
[Various evaluations]
The obtained paint was subjected to various evaluations in the same manner as in Example 1. Various evaluation results are shown in Table 1.

[Comparative Example 7]
In “Preparation of black paint for preventing internal reflection” in Example 1, Dispersant A added at the time of mill base preparation was replaced with 0.083 parts by mass, Nipponran 983 was replaced with 1.501 parts by mass, and methyl isobutyl ketone 2.232 parts by mass. In the same manner as in Example 1 except that the above was obtained, a base material for paint h was obtained.
8.97 parts by mass of the main component of this paint and 1.03 parts by weight of isocyanate A were placed in a container and stirred, and diluted with methyl isobutyl ketone in the same manner as in Example 1 to obtain paint. The initial viscosity value of this paint was 43.2 mPa · s, and the contents of titanium dioxide and carbon black in the paint solids were 45.1 mass% and 5.0 mass%, respectively.
[Various evaluations]
The obtained paint was subjected to various evaluations in the same manner as in Example 1. Various evaluation results are shown in Table 1.

[Comparative Example 8]
In Example 1 “Preparation of black paint for internal reflection prevention”, the dispersant D added during mill base preparation was not added, and Nipponran 983 was replaced with 1.940 parts by mass and methyl isobutyl ketone 2.937 parts by mass. Was the same as in Example 1 to obtain a base material for paint.
8.67 parts by mass of the main component of this paint and 1.33 parts by mass of isocyanate A were placed in a container and stirred, and diluted with methyl isobutyl ketone in the same manner as in Example 1 to obtain a paint. The initial viscosity value of this paint was 46.6 mPa · s, and the contents of titanium dioxide and carbon black in the solid content of the paint were 45.1% by mass and 5.0% by mass, respectively.
[Various evaluations]
The obtained paint was subjected to various evaluations in the same manner as in Example 1. Various evaluation results are shown in Table 1.

[Comparative Example 9]
In Example 1 "Preparation of black anti-reflective coating," dispersant D added during mill base preparation was replaced with 0.550 parts by weight of dispersant G, and methyl isobutyl ketone was replaced with 3.044 parts by weight. In the same manner as in Example 1, a main component of paint paint was obtained.
8.94 parts by mass of the main component of this paint and 1.06 parts by mass of isocyanate A were placed in a container and stirred, and diluted with methyl isobutyl ketone in the same manner as in Example 1 to obtain a paint. The initial viscosity value of the paint film was 40.7 mPa · s, and the contents of titanium dioxide and carbon black in the solid content of the paint were 45.1% by mass and 5.0% by mass, respectively.
[Various evaluations]
The obtained paint was subjected to various evaluations in the same manner as in Example 1. Various evaluation results are shown in Table 1.

1 Lens 2 Internal antireflection black paint film 3 Incident light (external light)
4 Internal reflection light (stray light)
5 Right triangle prism (30 x 30 mm, t15 mm, apex angle 90 °)
6 Light source (spectrum in units of 5 nm is possible between 400 and 700 nm)
7 Incident light 8 Internal reflection light 9 Φ60 mm integrating sphere with photodetector 10 Vertical line (perpendicular) to prism bottom
11 Contact surface with integrating sphere entrance 12 Polarizing plate (set to N polarization)
13 Slit (Vertical 1mm x Horizontal 3mm Aperture)
θ Angle A between incident light 7 and perpendicular 10 Distance from perpendicular 10 from prism apex to integrating sphere entrance 11 (15 · √2 mm)
B Integral sphere opening diameter (φ15mm)

Claims (5)

In the inner surface antireflection black paint for optical elements containing at least titanium dioxide, carbon black, a binder resin, a dispersant, and a solvent, the titanium dioxide has a methanol hydrophobization degree of 30% or more and 80% or less. The pH is 3.0 or more and 8.0 or less, the average primary particle diameter is 7 nm or more and 50 nm or less, and 35% by mass or more and 75% by mass with respect to the solid content of the inner surface antireflection black paint for optical elements. % Or less,
The carbon black has a volatile content of 0.6 mass% to 6.0 mass%, a pH of 3.0 to 8.0, an average primary particle size of 14 nm to 80 nm, and 2% by mass or more and 20% by mass or less based on the solid content of the inner surface antireflection black paint for optical elements,
The dispersant is a combination of a phthalocyanine compound and a polymer dispersant,
The phthalocyanine compound is contained in an amount of 1% by mass to 20% by mass with respect to 100% by mass of the carbon black,
The polymer dispersant has an amine value of 5 mgKOH / g or more and 100 mgKOH / g or less, and is contained in an amount of 5% by mass or more and 40% by mass or less when the total of the titanium dioxide and the carbon black is 100% by mass. An internal reflection-preventing black paint for optical elements. The DBP absorption amount of the carbon black is 40 ml / 100 g or more and 170 ml / 100 g or less, the inner surface antireflection black paint for optical elements according to claim 1 . The pH of the said phthalocyanine compound is 3.0 or more and 8.0 or less, The inner surface antireflection black coating material for optical elements of Claim 1 or 2 characterized by the above-mentioned. The inner surface antireflection black paint for optical elements according to any one of claims 1 to 3, wherein the phthalocyanine compound is a copper phthalocyanine compound. As the binder resin, at least an epoxy resin, a polyurethane resin, an acrylic resin, a polyester resin, the inner surface antireflection optical device according to any one of claims 1 to 4, characterized in that it contains one of the silicone resin Black paint.

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