CN103842098A - Method of manufacturing object with low reflection film - Google Patents

Abstract

The present invention provides a kind of substrate that can deal with wider width, can make the conveying speed of substrate faster, the amount of required coating composition is less, drying or firing time and coating time are shorter, can form A method for producing a low-reflection film-attached article having a low-reflection film of uniform film thickness and easily forming a low-reflection film with an arbitrary film thickness that can be optically designed (excellent in film thickness controllability). This production method is characterized in that when the coating composition (20) is applied by the coating roll (14) of the reverse roll coater (10) on the substrate (2) conveyed in a predetermined direction to form a low reflection film , the rotation speed of the coating roller (14) is slower than the conveying speed of the substrate (2), and as the coating composition (20), the microparticles (b) comprising the dispersion medium (a) and dispersed in the dispersion medium (a) are used ), and a binder (c) dissolved or dispersed in the dispersion medium (a), and a coating composition having a viscosity of 1 to 10 mPa·s.

Description

Manufacturing method of article with low reflection film

technical field

The present invention relates to a method of manufacturing an article having a low reflection film on a substrate.

Background technique

Articles having an anti-reflection function have been put into practical use in order to reduce reflection of external light or increase light transmittance. As a method for imparting an antireflection function, there is known a method of forming a low reflection film on a base material by a wet coating method (spin coating method, spray coating method, roll coating method, etc.).

The spin coating method is a method of applying the low-reflection film-forming coating composition on the base material by dropping the low-reflection film-forming coating composition on the base material, rotating the base material, and utilizing centrifugal force.

The spray coating method is a method of applying the coating composition for forming a low-reflection film on a substrate by spraying the coating composition for forming a low-reflection film from a shower head onto a substrate conveyed in a predetermined direction.

The roll coating method is a method of applying the low-reflection film-forming coating composition on the base material by transferring the low-reflection film-forming coating composition coated on the surface of the roll to the base material conveyed in a predetermined direction.

However, the spin coating method has the following problems.

·When the base material is enlarged, it is difficult to rotate the base material.

- The low-reflection film tends to become thicker around the periphery of the substrate, and the uniformity of the film thickness of the low-reflection film is poor.

- Since the excess coating composition for low reflection film formation is thrown off from a base material by centrifugal force, the quantity of the coating composition for low reflection film formation required increases.

In addition, the spray coating method has the following problems.

・Because it is necessary to reciprocate the nozzle along the width direction of the substrate, in order to uniformly form a low-reflection film on a wide substrate, it is necessary to arrange multiple nozzles along the conveyance direction of the substrate, or to slow down the conveyance of the substrate speed.

- Since there are many coating compositions for forming a low reflection film scattered into the air without adhering to the base material, the amount of the coating composition for forming a low reflection film required increases.

A roll coating method can be mentioned as a wet coating method that can cope with a wide substrate, can increase the conveyance speed of the substrate, and requires a small amount of the coating composition for forming a low reflection film.

However, the roll coating method has the following problems.

· It was difficult to adjust the gap between the base material and the coating roller, and the uniformity of the film thickness of the low reflection film was poor.

- When the viscosity of the coating composition for low reflection film formation is low, it becomes difficult to form the low reflection film which has arbitrary film thickness which can be optically designed. That is, the film thickness controllability is poor.

·In order to form a low-reflection film having an arbitrary film thickness that can be optically designed, if the viscosity of the coating composition for forming a low-reflection film is increased or repeated coating is performed, drying or firing time and coating time will become longer.

As a roll coating method capable of forming a metal oxide film having a uniform film thickness, the following methods have been proposed.

A method of forming a metal acid compound film by applying a coating composition containing a metal compound and an organic solvent on a substrate conveyed in a predetermined direction by a coating roll of a reverse roll coater, and firing the coating composition, wherein The metal compound concentration (oxide conversion) of the coating composition is 0.1 to 10% by mass, the viscosity of the coating composition is 0.1 to 100 mPa·s, the rotation speed of the coating roller is 2 to 55 m/min, and the The conveyance speed is 1 to 30 m/min, and the method in which the rotation speed of the coating roller is faster than the conveyance speed of the substrate (see Patent Document 1).

However, when this method is used, it is difficult to form a low-reflection film having an arbitrary film thickness that can be optically designed when reducing the viscosity of the coating composition, that is, there is a problem that film thickness controllability is poor.

prior art literature

patent documents

Patent Document 1: Japanese Patent Laid-Open No. 07-068219

Contents of the invention

The technical problem to be solved by the invention

The present invention provides a kind of substrate that can deal with wider width, can make the conveying speed of substrate faster, the amount of required coating composition is less, drying or firing time and coating time are shorter, can form A method for producing a low-reflection film with a uniform film thickness and an article with a low-reflection film that can easily form a low-reflection film with an arbitrary film thickness that can be optically designed (that is, has excellent film thickness controllability).

Technical solutions adopted to solve technical problems

The method for producing an article with a low-reflection film of the present invention is a method for producing an article with a low-reflection film on a base material, and is characterized in that the method includes coating by reverse roll on the above-mentioned base material transported in a predetermined direction. Coating roller of a coating machine applies a coating composition to form the above-mentioned low-reflection film; as the above-mentioned coating composition, a dispersion medium (a), fine particles (b) dispersed in the above-mentioned dispersion medium (a) and dissolved or The binder (c) dispersed in the dispersion medium (a) above, and a coating liquid having a viscosity of 1.0 to 10.0 mPa·s; The rotation speed (that is, peripheral speed; "rotational speed" in the present invention means peripheral speed) of the above-mentioned coating roller is set to be slower than the conveyance speed of the above-mentioned base material.

The above-mentioned coating composition preferably further contains the terpene derivative (d) dissolved or dispersed in the above-mentioned dispersion medium (a).

The quantity of the said terpene derivative (d) is preferably 0.01-2 mass parts with respect to 1 mass part of solid content of the said coating composition.

The solid content concentration of the coating composition is preferably from 1 to 9% by mass.

The mass ratio of the fine particles (b) to the binder (c) (fine particles (b)/binder (c)) is preferably from 10/90 to 95/5.

The conveying speed of the base material is preferably from 3 to 20 m/min.

The rotation speed of the coating roller is preferably not less than 0.28 times and not more than 0.98 times the conveyance speed of the substrate.

The surface hardness (JIS-A standard) of the said coating roller is preferably 10-70.

The base material is preferably patterned glass having pear-skin-like irregularities formed on at least one surface.

The above-mentioned "～" indicating a numerical range is used in the meaning including the numerical values described before and after it as the lower limit value and the upper limit value. Unless otherwise specified, it is also used in the same meaning in the description below. "~".

The effect of the invention

By the method for producing an article with a low-reflection film of the present invention, it is possible to cope with wider substrates, to enable faster conveyance of the substrate, to require less amount of coating composition, drying or firing time and The coating time is short, a low-reflection film having a uniform film thickness can be formed, and a low-reflection film having an arbitrary film thickness that can be optically designed can be easily formed, that is, excellent film thickness controllability.

Description of drawings

Fig. 1 is a cross-sectional view showing an example of an article with a low reflection film of the present invention.

Fig. 2 is a cross-sectional view showing another example of the article with a low reflection film of the present invention.

Fig. 3 is a schematic diagram showing an example of a reverse roll coater.

Detailed ways

<Items with low reflection film>

FIG. 1 is a cross-sectional view showing an example of an article with a low reflection film obtained by the production method of the present invention. The article 1 with a low reflection film has a base material 2 and a low reflection film 3 formed on the surface of the base material 2 .

(Substrate)

As a material of the base material 2, glass, metal, resin, silicon, wood, paper, etc. are mentioned. As glass, soda lime glass, borosilicate glass, aluminosilicate glass, non-alkali glass, mixed alkali-containing glass, etc. are mentioned, for example. The resin may, for example, be polyethylene terephthalate, polycarbonate, triacetyl cellulose or polymethyl methacrylate.

The shape of the substrate 2 is not particularly limited, and generally, a plate, a film, and the like may be mentioned.

As the substrate 2 for a cover glass of a solar cell, patterned glass having a pear-skin-like pattern with concavities and convexities on the surface is preferable. As the above-mentioned glass, as a material for patterned glass, soda-lime glass with less iron content and higher transparency than soda-lime glass (generally called ordinary plate glass) used for ordinary window glass and the like is preferred. (ie, high transmission glass, commonly known as ultra-clear flat glass). The ultra-white flat glass is represented by the mass percentage of the oxide standard, and preferably has the following composition: SiO ₂ : 65-75%, Al ₂ O ₃ : 0-10%, CaO: 5-15%, MgO: 0-10%. 15%, Na ₂ O: 10-20%, K ₂ O: 0-3%, Li ₂ O: 0-5%, Fe ₂ O ₃ : 0-3%, TiO ₂ : 0-5%, CeO ₂ :0～3％, BaO:0～5％, SrO:0～5％, B ₂ O ₃ :0～15％, ZnO:0～5％, ZrO ₂ :0～5％, SnO ₂ :0～5％ 3%, SO ₃ : 0-0.5%. In addition, when the substrate 2 is an alkali-free glass, it preferably has the following composition: SiO ₂ : 39-70%, Al ₂ O ₃ : 3-25%, B ₂ O ₃ : 1-30%, MgO: 0-10%, CaO: 0-17%, SrO: 0-20%, BaO: 0-30%. In addition, when the base material 2 is mixed with alkali-containing glass, it is expressed in mass percent based on oxides, and preferably has the following composition: SiO ₂ : 50 to 75%, Al ₂ O ₃ : 0 to 15%, MgO+CaO+SrO+BaO+ZnO: 6-24%, Na ₂ O+K ₂ O: 6-24%.

As shown in FIG. 2 , the substrate 2 may have a functional layer 5 on the surface of the substrate main body 4 .

As the functional layer 5, a primer layer, an adhesion improving layer, a protective layer, etc. are mentioned.

The undercoat layer functions as an alkali metal barrier layer and a broadband low-refractive index layer. As an undercoat layer, it is preferable to apply an undercoating coating composition comprising a hydrolyzed product of alkoxysilane (gel silica, that is, a silica precursor based on a sol-gel method) on a substrate. layer formed. When coating the below-mentioned coating composition for low-reflection films on the undercoat layer, the undercoat layer may be baked in advance or may be in a wet state. In the case of coating a coating composition for a low-reflection film on the primer layer, the coating temperature (that is, the substrate temperature at the time of coating) is preferably from room temperature to 80°C, and the firing of the coated coating film The temperature is preferably from 30 to 700°C. The film thickness of the undercoat layer is preferably from 10 to 500 nm.

(low reflective film)

The low-reflection film 3 is formed by once coating a coating liquid of a coating composition described later, and is preferably a single-layer film containing a binder (c) or a fired product thereof, and fine particles (b). When the binder is a hydrolyzate of alkoxysilane, the low reflection film 3 is a film in which fine particles (b) are dispersed in a matrix formed of a fired product (SiO ₂ ) of a hydrolyzate of alkoxysilane. When the binder is a resin, the low-reflection film 3 is a film in which fine particles (b) are dispersed in a resin matrix.

The film thickness of the low reflection film 3 is preferably from 50 to 300 nm, more preferably from 80 to 200 nm. When the film thickness of the low reflection film 3 is 50 nm or more, interference of light occurs, and antireflection performance is exhibited. If the film thickness of the low reflection film 3 is 300 nm or less, it can form into a film without cracking.

The film thickness of the low-reflection film 3 can be measured with a reflection spectroscopic film thickness meter.

The reflectance of the low reflection film 3 is preferably at most 2.6%, more preferably at most 1.0%, in terms of the lowest value (so-called minimum reflectance) within a wavelength range of 300 to 1200 nm.

<Manufacturing method of article with low reflection film>

The manufacturing method of the article with the low-reflection film of the present invention is a method as follows: on the substrate 2 conveyed in a predetermined direction, the coating liquid of the coating composition described later is coated by the coating roll of the reverse roll coater, If necessary, the formed coating film is fired or dried to be cured to form the low reflection film 3 .

(Reverse Roll Coater)

Fig. 3 is a schematic diagram showing an example of a reverse roll coater.

The reverse roll coater 10 is equipped with a conveying belt 12, a coating roller 14, a doctor roller 16, a backup roller 18, a first doctor blade 22, and a second doctor blade 24; the conveying belt 12 conveys a substrate 2 in a predetermined direction; The coating roller 14 is arranged with a predetermined gap above the conveyor belt 12 in such a way that its rotation axis direction is perpendicular to the direction of travel of the conveyor belt 12, and rotates in a direction opposite to the direction of travel of the conveyor belt 12; The doctor roll 16 (also referred to as a metering roll) is arranged on the downstream side of the travel direction of the conveyor belt 12 than the coating roll 14, and is in contact with the coating roll 14 with a predetermined pressing thickness; The belt 12 is in contact with the conveyor belt 12 and is arranged under the coating roller 14, and rotates in the same direction as the travel direction of the conveyor belt 12; The liquid accumulation of the coating composition 20 supplied to the surface of the doctor roller 16 is arranged in such a way that it is in contact with the surface of the upper half of the doctor roller 16; Configured in such a manner as to scrape off the coating composition 20 that has not migrated to the surface of the coating roll 14 of the substrate 2 .

In addition, instead of the conveyance belt 12 , a plurality of conveyance rollers may be aligned along the conveyance direction of the substrate 2 so that the direction of the rotation axis is perpendicular to the traveling direction of the conveyance belt 12 .

(coating method)

In the reverse roll coater 10, the coating composition 20 is coated on the surface of the substrate 2 as follows to form a coating film.

The coating composition 20 is supplied to the surface of the doctor roll 16 from above the doctor roll 16 . A predetermined amount of coating composition 20 adhering to the surface of the doctor roll 16 between the doctor roll 16 and the first doctor blade 22 moves toward the coating roll 14 side as the doctor roll 16 rotates. At this time, the movement of the coating composition 20 is restricted by the first scraper 22, so the coating composition 20 that cannot pass between the scraper roll 16 and the first scraper 22 is accumulated between the scraper roll 16 and the first scraper 22, forming an accumulation. liquid.

The coating composition 20 adhering to the surface of the doctor roll 16 and moving toward the coating roll 14 is transferred to the surface of the coating roll 14 while maintaining a predetermined amount between the coating roll 14 and the doctor roll 16 . At this time, the transfer of the coating composition 20 is restricted by the doctor roller 16, so the coating composition 20 that cannot pass between the coating roller 14 and the doctor roller 16 accumulates between the coating roller 14 and the doctor roller 16, forming a liquid accumulation. . The coating composition 20 transferred to the surface of the coating roller 14 moves toward the conveyance belt 12 side as the coating roller 14 rotates.

The coating composition 20 adhering to the surface of the coating roller 14 and moving toward the conveyor belt 12 is transferred to the substrate 2 in a predetermined amount depending on the gap between the conveyor belt 12 and the coating roller 14 and the thickness of the substrate 2 . surface, forming a coating film. At this time, the coating composition 20 that has not been transferred to the surface of the substrate 2 moves toward the second blade 24 side with the rotation of the coating roller 14 in a state of adhering to the surface of the coating roller 14. It scrapes off the surface of the applicator roll 14 .

The first scraper 22 and the second scraper 24 are respectively arranged on the scraper roll 16 and the coating roll 14, so the surface of the scraper roll 16 is not transferred to the surface of the scraper roll 14 and the surface of the scraper roll 16 is The streaks of the coating composition 20 remaining in the form of streaks and the streaks of the coating composition 20 remaining in the form of streaks on the surface of the coating roll 14 without being transferred from the surface of the coating roll 14 to the surface of the substrate 2 can pass through the second coating composition 20. The first doctor blade 22 and the second doctor blade 24 are eliminated, and as a result, the film thickness of the coating film of the coating composition 20 applied on the substrate 2 can be made uniform.

(coating roller)

As the coating roller 14, a rubber-lined roller lined with rubber is generally used.

The surface hardness (JIS-A standard) of the coating roller 14 is preferably from 10 to 70, more preferably from 20 to 50. When the hardness is 10 or more, it is easy to control the film thickness of the coating film of the coating composition 20 applied on the substrate 2 . If the hardness is 70 or less, even when patterned glass is used as the substrate 2, the surface of the coating roller 14 can follow the unevenness of the surface of the patterned glass, and the film thickness of the coating film of the coating composition 20 can be made uniform.

(rotational speed of coating roller)

When coating the above-mentioned coating composition on a base material, the rotation speed (that is, the peripheral speed) of the coating roller 14 is made slower than the conveyance speed of the base material 2 . By making the rotation speed of the coating roller 14 slower than the conveyance speed of the base material 2, it is easy to form a low-reflection film having an arbitrary film thickness that can be optically designed (that is, excellent film thickness controllability). From the viewpoint of more excellent film thickness controllability, the rotational speed of the coating roller 14 is preferably at least 0.28 times and at most 0.98 times the conveying speed of the substrate 2, more preferably at least 0.98 times the conveying speed of the substrate 2. The transport speed is 0.35 times or more and 0.90 times or less of the transport speed of the substrate 2 .

In addition, in Patent Document 1, in order to make the film thickness uniform, the rotation speed of the coating roller 14 is set to be faster than the conveyance speed of the substrate 2, but in the present invention, even if the coating is made The rotation speed of the roller 14 is slower than the conveyance speed of the base material 2, and the film thickness of the coating film of the coating composition 20 applied on the base material 2 can also be made uniform.

(scraper roller)

As the doctor roll 16 , a metal roll whose surface is made of metal or a rubber-lined roll lined with rubber is generally used.

As the doctor roll 16, from the viewpoint of easily holding the coating composition 20 on the surface of the doctor roll 16, it is preferable to form a multi-groove doctor roll on the surface, so that the coating composition coated on the substrate 2 can be easily formed. From the viewpoint of uniform film thickness of 20, a doctor roll having grid-shaped grooves formed on the surface is more preferable.

(extrusion thickness)

The extrusion thickness of the scraper roll 16 to the coating roll 14 (this extrusion thickness refers to that when the coating roll 14 and the scraper roll 16 are configured, the rubber lining on the surface of the coating roll when the scraper roll is squeezed) 0.1-1.0 mm, more preferably 0.1-1.0 mm, more preferably 0.3-0.9 mm. If the extruded thickness is within this range, it is easy to make the thickness of the coating film of the coating composition 20 applied on the substrate 2 uniform, and in addition, it is easy to control the thickness of the coating composition 20 applied on the substrate 2. The film thickness of the film.

(gap)

The gap between the conveyor belt 12 and the coating roller 14 can be appropriately adjusted according to the thickness of the base material 2 , the film thickness of the coating composition 20 coated on the base material 2 , and the like.

(Conveying speed of base material)

The conveyance speed of the substrate 2 is preferably from 3 to 20 m/minute, more preferably from 5 to 15 m/minute. If the conveyance speed of the base material 2 is 3 m/min or more, productivity will improve. If the conveyance speed of the base material 2 is 20 m/min or less, it becomes easy to control the film thickness of the coating film of the coating composition 20 applied on the base material 2.

(temperature)

The coating temperature (the coating temperature refers to the temperature of the substrate when coating the substrate surface) is preferably from room temperature to 80°C, more preferably from room temperature to 60°C.

The drying or firing temperature of the coating film of the coating composition is preferably at least 30°C, and can be appropriately determined according to the materials of the substrate 2, the fine particles (b) or the binder (c). For example, when the materials of the substrate 2, the microparticles (b) or the binder (c) are all resins, the drying or firing temperature is 30° C. or higher and the heat-resistant temperature of the resin is lower, but even at this temperature, the A sufficient anti-reflection effect can be obtained. When the base material 2 is glass, the firing temperature is preferably at least 30°C and at most 750°C. When the base material 2 is glass, the firing step of the low-reflection film 3 and the physical strengthening step of the glass can also be combined into one. In the physical strengthening process, the glass is heated to around the softening temperature. At this time, the firing temperature is set in the range of about 600°C to about 700°C. The firing temperature is usually preferably set to be equal to or less than the heat distortion temperature of the base material 2 . The lower limit of the firing temperature is determined according to the formulation of the coating composition 20 . A certain degree of polymerization occurs even in natural drying, so theoretically, the drying or firing temperature can be set to a temperature around room temperature if there is no time limit.

(coating composition)

The coating composition 20 includes a dispersion medium (a), fine particles (b) dispersed in the dispersion medium (a), and a binder (c) dissolved or dispersed in the dispersion medium (a), including dissolved or dispersed particles as needed. The terpene derivative (d) in the dispersion medium (a) may contain other additives as necessary. The coating composition 20 can be prepared, for example, by mixing a fine particle (b) dispersion, a binder (c) solution, a dispersion medium (a), a terpene derivative (d), and other additives if necessary.

The viscosity of the coating composition 20 as a coating liquid is 1.0 to 10.0 mPa·s, preferably 2.0 to 5.0 mPa·s. When the viscosity of the coating composition 20 is 1.0 mPa·s or more, it is easy to control the film thickness of the coating film of the coating composition 20 applied on the substrate 2 . If the viscosity of the coating composition 20 is 10.0 mPa·s or less, the drying or firing time and coating time are shortened.

The viscosity of the coating composition 20 can be measured with a B-type viscometer.

The solid content concentration of the coating composition 20 is preferably from 1 to 9 mass%, more preferably from 2 to 6 mass%. When the solid content concentration is 1 mass % or more, the film thickness of the coating film of the coating composition 20 can be made thin, and it becomes easy to make the film thickness of the low reflection film 3 finally obtained uniform. When the solid content concentration is 9% by mass or less, it is easy to make the film thickness of the coating film of the coating composition 20 coated on the substrate 2 uniform.

The solid content of the coating composition 20 refers to the sum of the fine particles (b) and the binder (c) (however, when the binder (c) is a hydrolyzed product of alkoxysilane, the solid content concentration is SiO ₂ conversion).

The amount of the terpene derivative (d) is preferably from 0.01 to 2 parts by mass, more preferably from 0.03 to 1 part by mass, based on 1 part by mass of solid content of the coating composition 20 . When the amount of the terpene derivative (d) is at least 0.01 parts by mass, the antireflection effect is sufficiently high compared to the case where the terpene derivative (d) is not added. When the terpene derivative (d) is 2 parts by mass or less, the strength of the low reflection film 3 will be favorable.

The mass ratio of the fine particles (b) to the binder (c) (fine particles (b)/binder (c)) is preferably from 10/90 to 95/5, more preferably from 70/30 to 90/10. When fine particle (b)/binder (c) is 95/5 or less, the adhesiveness of the low reflection film 3 and the base material 2 is high enough. When the fine particle (b)/binder (c) ratio is 10/90 or more, the antireflection effect is sufficiently high.

(dispersion medium (a))

As the dispersion medium (a) (except for the following terpene derivatives (d)), water, alcohols (methanol, ethanol, isopropanol, butanol, diacetone alcohol, etc.), ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.), ethers (tetrahydrofuran, 1,4-di alkane, etc.), cellosolves (methyl cellosolve, ethyl cellosolve, etc.), esters (methyl acetate, ethyl acetate, etc.), glycol ethers (ethylene glycol monoalkyl ether, etc. ), nitrogen-containing compounds (N,N-dimethylacetamide, N,N-dimethylformamide, N-methylpyrrolidone, etc.), sulfur-containing compounds (dimethyl sulfoxide, etc.), etc.

Since water is required for hydrolysis of alkoxysilane, the dispersion medium (a) when the binder (c) is a hydrolyzed product of alkoxysilane needs to contain water.

The dispersion medium (a) is preferably appropriately selected according to the substrate 2 or the binder (c).

As the dispersion medium (a) when the substrate 2 is carbonate, an alcohol dispersion medium containing a solvent capable of dissolving polycarbonate (such as a nitrogen-containing compound, etc.) is preferable.

As the dispersion medium (a) when the substrate 2 is polyethylene terephthalate, an alcohol dispersion containing a solvent capable of dissolving polyethylene terephthalate (for example, dichloromethane, etc.) is preferred. medium.

When the substrate 2 is triacetyl cellulose, polyester, acrylic resin, silicone resin, etc. are used as the binder (c), and the dispersion medium (a) when the binder (c) is polyester is relatively Ethyl acetate and the like are preferred.

(particles (b))

As the fine particles (b), at least one selected from metal oxide fine particles, metal fine particles, pigment-based fine particles, and resin fine particles can be cited as a suitable material.

The material of the metal oxide fine particles may, for example, be selected from Al ₂ O ₃ , SiO ₂ , SnO ₂ , TiO ₂ , ZrO ₂ , ZnO, CeO ₂ , SnO _X (ATO) containing Sb, and In ₂ O containing Sn. ₃ (ITO), and at least one of RuO ₂ as a suitable material. Among them, SiO ₂ is suitable as a material of the low reflection film 3 from the viewpoint of a low refractive index, and thus is particularly preferable.

Examples of the material of the metal fine particles include metals such as Ag and Ru, alloys such as AgPd and RuAu, and the like.

Examples of the pigment-based fine particles include inorganic pigments such as titanium black and carbon black, and organic pigments.

The material of the resin fine particles may, for example, be polystyrene or melamine resin.

The shape of the fine particles (b) may, for example, be spherical, elliptical, needle-like, plate-like, rod-like, conical, cylindrical, cubic, cuboid, diamond-like, star-like, or irregular. In addition, the microparticles (b) may be hollow, open-pored, or interconnected-pored. The fine particles (b) may exist in a state where each fine particle is independent, each fine particle may be connected in a chain, or each fine particle may be aggregated. As the fine particles (b), fine particles of the above-mentioned shapes may be present in admixture.

The fine particles (b) may be used alone or in combination of two or more.

The average aggregated particle size of the microparticles (b) is preferably from 1 to 1000 nm, more preferably from 3 to 500 nm, further preferably from 5 to 300 nm. When the average aggregated particle size of the fine particles (b) is at least 1 nm, the antireflection effect is sufficiently high. When the average aggregated particle size of the fine particles (b) is at most 1000 nm, the haze of the low reflection film 3 can be kept low.

The average aggregated particle diameter of the fine particles (b) is the average aggregated particle diameter of the fine particles (b) in the dispersion medium (a), and is measured by a dynamic light scattering method. When aggregated monodisperse fine particles (b) cannot be observed, the average aggregated particle diameter is equivalent to the average primary particle diameter.

The low-reflection film 3 of the present invention exhibits an anti-reflection effect due to the voids selectively formed around the particles (b), so as the material of the particles (b), it is not necessary to use a low-refractive-index material (such as SiO ₂ ). Therefore, it is possible to form the low-reflection film 3 having various properties possessed by the microparticles (b) and an antireflection effect. For example, when the material of the particles (b) is SiO ₂ , the refractive index of the low-reflection film 3 can be further lowered, so that the low-reflection film 3 with sufficiently low reflectance can be formed. When the material of the fine particles (b) is ATO, the low-reflection film 3 having both conductivity and/or infrared shielding properties and an antireflection effect can be formed. When the material of the microparticles (b) is CeO ₂ or ZnO, the low-reflection film 3 having both ultraviolet absorption and antireflection effects can be formed. In addition, even when the material of the particle (b) is TiO ₂ with a high refractive index, the low-reflection film 3 can be formed in the form of a single-layer coating that was previously unimaginable, so it can be formed with the hydrophilicity possessed by TiO ₂ Low-reflection film 3 with antibacterial properties and anti-reflection effects. When the material of the fine particles (b) is an organic pigment or an inorganic pigment, a colored low-reflection film 3 can be formed, and a colored filter having an antireflection function can be produced.

(Binder (c))

The binder (c) may, for example, be a hydrolyzed product of alkoxysilane (sol-gel silica, that is, a silica precursor based on a sol-gel method), a resin (such as a thermoplastic resin, a thermosetting resin, or UV curable resin, etc.) etc.

The binder (c) is preferably appropriately selected according to the substrate 2 .

When the base material 2 is glass, the binder (c) is preferably a hydrolyzed product of alkoxysilane.

Examples of alkoxysilanes include tetraalkoxysilanes (tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane, etc.), alkoxysilanes having perfluoropolyether groups, etc. base silanes (perfluoropolyether triethoxysilane, etc.), alkoxysilanes with perfluoroalkyl groups (perfluoroethyl triethoxysilane, etc.), alkoxysilanes with vinyl groups (vinyl Trimethoxysilane, vinyltriethoxysilane, etc.), alkoxysilanes with epoxy groups (2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxy Propyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, etc.), alkoxysilanes with acryloyloxy groups ( 3-acryloxypropyltrimethoxysilane, etc.), etc.

In the case of tetraalkoxysilane, the hydrolysis of the alkoxysilane is carried out using water which is 4 times or more the molar amount of the alkoxysilane, and an acid or a base as a catalyst. Examples of the acid include inorganic acids (HNO ₃ , H ₂ SO ₄ , HCl, etc.) and organic acids (formic acid, oxalic acid, monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, etc.). The base may, for example, be ammonia, sodium hydroxide or potassium hydroxide. The catalyst is preferably an acid from the viewpoint of long-term storage stability. In addition, the catalyst is preferably one that does not inhibit the dispersion of the fine particles (b).

(terpene derivatives (d))

A terpene refers to a hydrocarbon having a composition of (C ₅ H ₈ ) _n (where n is an integer of 1 or more) having isoprene (C ₅ H ₈ ) as a constituent unit. Terpene derivatives refer to terpenes with functional groups derived from terpenes. Terpene derivatives (d) also comprise terpene derivatives of different degrees of unsaturation.

As the terpene derivative (d), from the viewpoint of the antireflection effect of the low-reflection film 3, a terpene derivative having a hydroxyl group and/or a carbonyl group in the molecule is preferred, preferably a terpene derivative having a hydroxyl group and an aldehyde group in the molecule. (-CHO), ketone (-C(=O)-), ester bond (-C(=O)O-), and carboxyl (-COOH) functional groups of terpene derivatives, more preferably It is a terpene derivative with more than one functional group selected from hydroxyl, aldehyde and ketone groups in the molecule.

酯等)等。特别优选萜烯醇。Terpene derivatives (d) include terpene alcohols (such as α-terpineol, terpinen-4-ol, L-menthol, (±) citronellol, myrtenol, orange flower alcohol, borneol, farnesol, phytol, etc.), terpene aldehydes (such as citral, β-ring citral, perillaldehyde, etc.), terpene ketones (such as (±) camphor, β-ionone etc.), terpene carboxylic acids (such as citronellic acid, abietic acid, etc.), terpene esters (such as terpineyl acetate, acetic acid

esters, etc.) etc. Particular preference is given to terpene alcohols.

The terpene derivatives (d) may be used alone or in combination of two or more.

(other additives)

As other additives, a surfactant for improving flatness, a metal compound for improving the durability of the low reflection film 3 , and the like may, for example, be mentioned.

As surfactants, silicone oils, acrylics, and the like may, for example, be mentioned.

As a metal compound, zirconium chelate, titanium chelate, aluminum chelate, etc. are preferable. As the zirconium chelate compound, zirconium tetraacetylacetonate, zirconium tributoxystearate, and the like may, for example, be mentioned.

(Effect)

In the method for producing an article with a low-reflection film of the present invention described above, the coating composition is applied as described above by the coating roll of the reverse roll coater, so it is possible to deal with wide substrates and make the substrates The handling speed of the material is faster, so the amount of coating composition required is less.

In addition, in the method for producing an article with a low-reflection film of the present invention described above, when the viscosity of the coating composition is 10 mPa·s or less, the drying or firing time and coating time are relatively short because of the relatively low viscosity. .

In addition, in the method for producing an article with a low reflection film of the present invention described above, since a specific coating composition is used and the rotation speed of the coating roll of the reverse roll coater is slower than the conveying speed of the substrate, the coating Even if the viscosity of the composition is relatively low, a low-reflection film having a uniform film thickness can be formed, and a low-reflection film having an arbitrary film thickness that can be optically designed can be easily formed. That is, the film thickness controllability is excellent.

In addition, since the above-described coating composition contains the above-mentioned various dispersion medium (a), fine particles (b) and binder (c), it can be produced at a low cost and at a relatively low cost by the reverse roll coater method. A low-reflection film with anti-reflection effect is formed at a low temperature.

That is, if a low-reflection film is formed by using the above-mentioned coating composition by the reverse roll coater method unique to the present invention, voids can be selectively formed around the particles (b) in the low-reflection film, and the voids can be utilized. Improve anti-reflection effect.

For example, when the film thickness is thick and non-uniform, volatilization of terpenes cannot proceed uniformly during firing, and voids cannot be formed as intended. On the other hand, if the film thickness is thin and uniform, the terpene is efficiently and smoothly volatilized during firing, and the places where the terpene exists remain as voids, and the volume of the voids increases, so the antireflection effect increases.

In addition, the article with the low-reflection film described above has a high anti-reflection effect, can be manufactured at low cost, and can be formed even at a relatively low temperature, so it has a high anti-reflection effect. Also, there are not so many restrictions on the substrates that can be used when manufacturing the article, and it can be manufactured at a low cost.

Example

Hereinafter, the present invention will be further described in detail through examples.

Examples 1 to 4 are examples, and examples 5 and 6 are comparative examples.

(Average primary particle size of fine particles)

The average primary particle size of fine particles is obtained by converting the specific surface area measured by the BET method and the volume of the spherical particles assuming that the spherical particles are uniformly dispersed in the carrier.

(Average aggregation particle size of fine particles)

The average aggregated particle size of the fine particles was measured with a dynamic light scattering particle size analyzer (MICROTRAC UPA, manufactured by Nikkiso Co., Ltd. (Nikkiso Co., Ltd.).

(viscosity)

The viscosity of the paint composition was measured by adjusting the liquid temperature to 25° C. in a constant temperature bath using a B-type viscometer (manufactured by Toki Sangyo Co., Ltd., Model BL).

(film thickness)

The film thickness of the low-reflection film was measured by using a reflection spectroscopic film thickness meter (Otsuka Electronics Co., Ltd. (Otsuka Electronics Co., Ltd.), FE3000) to measure the spectral reflectance, and the dispersion formula of nk Cauchy (n-kCauch _y ) was determined by the least square method The resulting curves were fitted to the measured reflectance curves for determination. Moreover, the film thickness of the low reflection film was measured at four places, and the average value, and the difference (variation) of the maximum value and the minimum value were calculated.

(Transmittance)

The transmittance of the article with a low reflection film was calculated by measuring the transmittance of light with a wavelength of 400 nm to 1100 nm using a spectrophotometer (manufactured by JASCO Corporation (JASCO Corporation), V670).

The transmittance difference was calculated based on the following formula (1).

Transmittance difference = transmittance of item with low reflection film - transmittance of substrate only...(1).

(Reflectivity)

A black polyvinyl chloride tape (vinyltape) was bonded to the surface of the substrate on the opposite side of the low reflection film so as not to contain air bubbles, and then the reflectance of the low reflection film of 100 mm×100 mm in the center of the substrate was measured. In addition, reflectance is the minimum reflectance in the range of wavelength 300-1200nm (that is, the minimum value in the range of wavelength 300-1200nm). When the wavelength showing the minimum reflectance is 380 nm or less or 780 nm or more, a spectrophotometer (manufactured by JASCO Corporation, V670) was used. When the wavelength showing the lowest reflectance is 380 to 780 nm, a spectrophotometer (manufactured by Otsuka Electronics Co., Ltd., instantaneous multi-spot photometry system MCPD-3000) was used.

(wear resistance)

Felt (manufactured by Shingo Rika Kogyo Co., Ltd. (Shinko Rika Kogyo) Co., Ltd. (Shinko Rika Kogyo Co., Ltd.), grinding pad AM-1) was installed on a grinding tester (manufactured by Ohira Rika Kogyo Co., Ltd. (Ohira Rika Kogyo)), and the felt was weighed at 1 kg. The load reciprocated horizontally on the surface of the low-reflection film, and the transmittance of the article with the low-reflection film after reciprocating the felt 40 times was measured by the same method as the method for measuring the above-mentioned transmittance.

The transmittance change was calculated based on the following formula (2).

Transmittance change = transmittance of article with low reflection film before abrasion resistance test - transmittance of article with low reflection film after abrasion resistance test ... (2).

(Exterior)

The appearance of the low-reflection film of the low-reflection film-attached article was observed with the naked eye, and the following criteria were used for evaluation.

○: There are no streaks or streaks in the film, and the film is uniform.

△: Some stripes and streaks can be confirmed.

×: Many stripes and streaks can be confirmed.

(Preparation of binder solution (c-1))

While stirring 77.6 g of modified ethanol (manufactured by Nippon Alcohol Sales Co., Ltd. (Nippon Alcoll Sales Co., Ltd.), SOLMIX AP-11, a mixed solvent with ethanol as the main ingredient, the same below), 11.9 g of ions were added thereto. The mixed liquid of water and 0.1 g of 61 mass % nitric acid was exchanged, and it stirred for 5 minutes. 10.4 g of tetraethoxysilane (SiO ₂ conversion solid content concentration: 29% by mass) was added thereto, and stirred at room temperature for 30 minutes to prepare a binder solution (c _- 1 ).

The solid content concentration in terms of SiO ₂ is the solid content concentration when all the Si in tetraethoxysilane is converted into SiO ₂ .

(Preparation of binder solution (c-2))

While stirring 80.4 g of modified ethanol (manufactured by Nippon Alcohol Trading Co., Ltd., SOLMIX AP-11, a mixed solvent with ethanol as the main ingredient, the same below), 11.9 g of ion-exchanged water and 0.1 g of A mixed solution of 61% by mass of nitric acid was stirred for 5 minutes. Add _7.6 g of tetraethoxysilane (SiO ₂ conversion solid content concentration: 29% by mass) to this, and stir at room temperature for 30 minutes to prepare a binder solution (c-2 ).

(Chain SiO ₂ particle dispersion (b-1))

Nissan Chemical Industry Co., Ltd. (Nissan Chemical Industry Co., Ltd.), trade name: "SNOWTEX OUP", SiO ₂ conversion solid content concentration: 15.5% by mass, average primary particle size: 10-20 nm, average aggregated particle size: 40-100 nm.

(Preparation of Coating Composition (A))

While stirring 24.5 g of modified ethanol, 24.0 g of isobutanol, 20.0 g of binder solution (c-1), 15.5 g of chain SiO _fine particle dispersion (b-1), 15.0 g Diacetone alcohol (hereinafter referred to as DAA), and 1.0 g of α-terpene alcohol as the terpene derivative (d) were used to prepare a coating composition (A) having a solid content concentration of 3.0% by mass. Its composition and viscosity are shown in Table 1.

(Preparation of Coating Compositions (B), (C))

Coating compositions (B) and (C) were prepared in the same manner as coating composition (A) except changing the compounding ratio shown in Table 1. Its composition and viscosity are shown in Table 1.

[Table 1]

[example 1]

Embossed glass (manufactured by Asahi Glass Co., Ltd., trade name: "Solite" (soda-lime glass (ultra-clear flat glass) with low iron content and high transmittance) was prepared as a base material, and embossed glass with pear skin-like patterns formed on the surface Embossed glass), size: 100mm×100mm, thickness: 3.2mm), use cerium oxide aqueous dispersion to grind and clean the pear skin pattern surface of embossed glass, wash away cerium oxide with water, rinse with ion-exchanged water, Let it dry.

Preheat the patterned glass with a preheating furnace (manufactured by ISUZU Co., Ltd., VTR-115), and keep the glass surface temperature of the patterned glass at 30°C. On the surface, the coating composition (A) was applied by a coating roll of a reverse roll coater (manufactured by Sanwa Seiki Co., Ltd. (Sanwa Seiki Co., Ltd.). Coating conditions are as follows.

The conveying speed of the substrate: 13.8m/min,

Rotational speed of coating roller: 9.0m/min,

The speed of the scraper roller: 9.0m/min,

Gap between coating roller and conveyor belt: 2.9mm,

Extrusion thickness of coating roller and scraper roller: 0.6mm.

As the coating roll, a rubber-lined roll with a surface hardness (JIS-A standard) of 30 and lined with rubber (EPDM rubber) was used. As the doctor roll, a metal roll having grid-shaped grooves formed on the surface was used.

Then, it baked at 500 degreeC for 30 minutes in air|atmosphere, and obtained the thing in which the low reflection film was formed. Rate this item. The results are shown in Table 2.

[Example 2~5]

Except having changed the coating composition and coating conditions into the coating composition and coating conditions shown in Table 2, it carried out similarly to Example 1, and obtained the article which formed the low reflection film. Rate this item. The results are shown in Table 2.

[Example 6]

The embossed glass kept at 30° C. with a preheating furnace was installed on a stand in a painting booth equipped with a spraying robot (manufactured by Kawasaki Robotics, JE005F), and the embossed glass was painted by spraying. Coating composition (X) is applied on top. Then, it baked at 500 degreeC for 30 minutes in air|atmosphere, and obtained the thing in which the low reflection film was formed. Rate this item. The results are shown in Table 2.

[Table 2]

In Example 1, it was found that a low-reflection film having a target film thickness was formed, and that the variation in the film thickness of the low-reflection film was small and the uniformity was good. In addition, in Examples 2 and 3, although the conveying speed was changed and the relative rotational speed was also changed, a uniform film was obtained in the same manner. In addition, in Example 4, the film obtained by changing the ratio of the fine particles and the binder also obtained a uniform film in the same manner.

In Example 5, since the rotation speed of the coating roller was made faster than the conveyance speed of the base material, a low reflection film having a target film thickness was not obtained.

In Example 6, since the low-reflection film was formed by the spray method, the variation in film thickness of the low-reflection film was not large.

Possibility of industrial use

The article with the low-reflection film obtained by the production method of the present invention can be used, for example, for cover glass of solar cells, displays (LCD, PDP, organic EL, CRT, SED, etc.), front panels of these displays, vehicles (automobiles, trams, Window glass for airplanes, window glass for housing, cover glass for touch panels, etc., which have an anti-reflection function in order to reduce the reflection of external light or increase the light transmittance.

The entire contents of the specification, claims, drawings, and abstract of Japanese Patent Application No. 2011-219241 filed on October 3, 2011 are cited here as disclosure of the specification of the present invention.

Explanation of symbols

1 item with low reflection film

2 base material

3 low reflection film

4 Substrate body

5 functional layers

10 reverse roll coater

12 conveyor belt

14 coating roller

16 scraper roller

18 backup rollers

20 coating composition

22 first scraper

24 second scraper

Claims (9)

1. A method for manufacturing an article with a low-reflection film, which is a method for manufacturing an article with a low-reflection film on a base material, characterized in that, The method includes the step of forming the low-reflection film by applying a coating composition on the substrate transported in a predetermined direction by a coating roll of a reverse roll coater; As the coating composition, a dispersion medium (a), fine particles (b) dispersed in the dispersion medium (a), and a binder (c) dissolved or dispersed in the dispersion medium (a) are used , and a coating liquid with a viscosity of 1.0 to 10.0 mPa·s; In the above step, the rotation speed of the coating roller when coating the coating composition on the base material is set to be slower than the conveyance speed of the base material. 2. The method for producing an article with a low reflection film according to claim 1, wherein the coating composition further comprises a terpene derivative (d) dissolved or dispersed in the dispersion medium (a) . 3. The method for producing an article with a low reflection film according to claim 2, wherein the amount of the terpene derivative (d) is 0.01 parts by mass relative to 1 part by mass of the solid content of the coating composition. ~2 parts by mass. 4. The method for producing an article with a low reflection film according to any one of claims 1 to 3, wherein the coating composition has a solid content concentration of 1 to 9% by mass. 5. The method of manufacturing an article with a low reflection film according to any one of claims 1 to 4, wherein the mass ratio of the particles (b) to the binder (c), that is, the particle (b)/binder (c) is 10/90 to 95/5. 6 . The method for producing an article with a low reflection film according to claim 1 , wherein the conveyance speed of the substrate is 3 to 20 m/min. 7. The method of manufacturing an article with a low reflection film according to any one of claims 1 to 6, wherein the rotation speed of the coating roller is 0.28 times or more and 0.98 times the conveying speed of the substrate. times below. 8 . The method for producing an article with a low reflection film according to claim 1 , wherein the coating roller has a surface hardness of 10-70 based on JIS-A. 8 . 9. The method of manufacturing an article with a low reflection film according to any one of claims 1 to 8, wherein the substrate is patterned glass having a pear-skin pattern formed on at least one surface.

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