JP2021038405A - Heat insulating film, heat insulating coating, and optical device - Google Patents

Abstract

To provide a heat insulating film that, even as a thin film, has high reflectance and resists a temperature rise due to sunlight, and has high thickness accuracy and high wear resistance, a heat insulating coating, and an optical device having such a heat insulating film.SOLUTION: A heat insulating film has a resin selected from urethane resin, acrylic resin, epoxy resin and a combination of them, the resin containing first particles with a d-ray refractive index of 2.5 or more and 3.2 or less, second particles with an average particle size of 5 nm or more and 100 nm or less, and holes of the second particles.SELECTED DRAWING: Figure 3

Description

The present invention relates to a heat shield film, a heat shield paint, and an optical device having such a heat shield film that may be used outdoors.

The heat shield film is a film having a function of suppressing a temperature rise of a member due to sunlight when used outdoors. Conventionally, as a method of suppressing a temperature rise of a member due to sunlight, a method of reflecting incident light 1 by the sun as reflected light 2 by an infrared reflecting film 4 is known as shown in FIG. By increasing the ratio of the reflected light 2 to the incident light 1, it is possible to suppress heat generation due to the transmitted light 3. As another heat shielding method, there is a method of providing a heat insulating layer having a low thermal conductivity instead of the infrared reflective film 4, providing a heat radiating layer for releasing heat to the outside, or a method of combining them.

On the other hand, since the heat-shielding film is a member that may come into contact with human hands, it is necessary to have abrasion resistance to withstand contact from the outside in addition to a function of suppressing a temperature rise. In addition, when used in optical equipment, it is necessary to adjust the focus, so position accuracy is important. For example, as shown in FIG. 2, the lens barrel of an optical instrument is composed of a lens 6 and a lens barrel 8 thereof, and is provided with a sliding fitting portion 7 for focusing adjustment. By providing the heat shield film 9 on the surface layer of the base material 5, even if the optical device is exposed to sunlight, the temperature rise of the optical device due to sunlight can be suppressed, and the position accuracy of the focal point and the like can be maintained. Therefore, it is necessary to control the variation in the film thickness of the coating film for precision equipment such as optical equipment.

Patent Document 1 discloses a heat-shielding film for a lens barrel, which is composed of a colored layer, an infrared reflecting layer, and a heat insulating layer. In Patent Document 1, not only the infrared reflective layer but also a heat insulating layer having a film thickness of 500 μm to 2000 μm is provided to enhance the heat shielding effect.
Patent Document 2 discloses a heat-shielding film having improved wear resistance by adding cerben having a particle size of 0.1 to 0.4 mm to a synthetic resin emulsion.

Japanese Unexamined Patent Publication No. 2009-139856 Japanese Unexamined Patent Publication No. 2015-81303

However, if a heat insulating layer having a film thickness of 500 μm to 2000 μm is provided as in Patent Document 1, the film thickness becomes thick and it is difficult to sufficiently obtain the positional accuracy of the sliding fitting portion.
Further, when celben having a large particle size is added as in Patent Document 2, it is difficult to obtain film thickness accuracy because large irregularities are formed on the surface.

The present invention has been made in view of such a background technique, and is a heat-shielding film and a heat-shielding film having high reflectance even in a thin film, little temperature rise due to sunlight, high film thickness accuracy, and high wear resistance. It is an object of the present invention to provide a coating material and an optical device having such a heat-shielding film.

The optical device of the present invention is an optical device having a lens and a lens barrel having the lens inside the lens barrel.
A heat shield film is provided on at least a part of the outer peripheral surface of the lens barrel.
The heat shield film contains first particles having a d-line refractive index of 2.5 or more and 3.2 or less in a resin selected from urethane resin, acrylic resin, epoxy resin, and a combination thereof. It is characterized by including a second particle having an average particle size of 5 nm or more and 100 nm or less, and a pore due to the second particle.
The heat shield film of the present invention is the first one having a d-line refractive index of 2.5 or more and 3.2 or less in a resin selected from urethane resin, acrylic resin, epoxy resin, and a combination thereof. It is characterized by including particles, second particles having an average particle size of 5 nm or more and 100 nm or less, and pores due to the second particles.

The heat-shielding coating material of the present invention has a d-line refractive index of 2.5 or more and 3.2 or less in a solution in which a urethane resin, an acrylic resin, an epoxy resin, or a resin selected from a combination thereof is dissolved in a solvent. It is characterized by including 1 particle, a second particle having an average particle diameter of 5 nm or more and 100 nm or less, and a pore by the second particle.

According to the present invention, a heat shield film, a heat shield coating, and an optical device having such a heat shield film have high reflectance, little temperature rise due to sunlight, high film thickness accuracy, and high wear resistance even in a thin film. Can be provided.

It is sectional drawing which shows the state of reflection and absorption of sunlight when the infrared reflection film is formed on the upper surface of a base material. It is sectional drawing of the lens barrel. It is sectional drawing which shows the reflection of a particle and a resin interface. It is a schematic diagram of the measurement form of the reflectance by a spectrophotometer. It is a schematic diagram which shows the evaluation method of temperature.

Hereinafter, preferred embodiments of the present invention will be described.
First, the mechanism for improving the reflectance of sunlight will be described. Next, the heat-shielding paint, the heat-shielding film, and the optical device having such a heat-shielding film for improving the reflectance of sunlight will be described.
The optical device of the present invention is an optical device having a lens and a lens barrel having the lens inside the lens barrel, and has a heat shield film on at least a part of the outer peripheral surface of the lens barrel.

In the present invention, the "resin matrix" means a resin in which pore-containing particles having an average particle size of 100 nm or less are contained in a urethane resin, an acrylic resin, an epoxy resin, or a resin selected from a combination thereof. However, the “pore-containing particles” refer to particles containing a hollow structure or a porous structure. The “high-refractive index particle” means a particle having a d-line refractive index of 2.5 or more and 3.2 or less.

In the present invention, the "particle size" is a diameter converted from the volume of particles, and is determined by a laser diffraction type particle size distribution meter.
Further, the median diameter was used as the "average particle size" in the present invention.

[Mechanism for improving sunlight reflectance]
The wavelength of sunlight is in the range of about 0.3 μm to about 3 μm, and when light of these wavelengths becomes transmitted light 3 as shown in FIG. 1, it is converted into thermal energy and the base material 5 generates heat. Therefore, in order to suppress heat generation due to sunlight without a heat insulating layer, it is necessary to increase the ratio of reflected light 2 to incident light 1 as much as possible to suppress heat generation due to transmission of light to the inside.

The wavelength range of 0.3 μm to 3 μm of sunlight is the region of Mie scattering for particles with a particle size of several μm, and when Mie scattering is calculated, when the particle size is around 1 μm, the sunlight The highest reflectance. Therefore, the particle size of the reflected particles of sunlight is generally around 1 μm. The formula of Light Scattering Theory (Department of Mechanical and Aerospace Engineering University of Florida; David W. Hahn) was used for the calculation of Mie scattering.

The present inventor has made extensive studies to further improve the reflectance, and found that the reflectance can be greatly improved by setting the particle size and refractive index of the particles and the refractive index of the resin within an appropriate range. It was.

First, it was found that the reflectance increases when particles having a d-line refractive index of 2.5 or more and 3.2 or less and an average particle size of 2 μm or more are used. This particle size is larger than 1 μm, which is the optimum solution for the calculated value of Mie scattering. A typical Mie scattering calculation calculates the sum of the scattering in all 360 ° directions with respect to the incident light. However, the only light that is actually reflected from the incident light and goes out of the film is backscattering. Therefore, the larger the particle size, the larger the shielding effect and the smaller the forward scattering. Therefore, in order to actually improve the reflectance, the particle size needs to be 2 μm or more. Further, when the average particle size exceeds 5 μm, the unevenness of the film becomes large and the film thickness accuracy deteriorates. Therefore, the average particle size of the particles in the present invention is 2 μm or more and 5 μm or less.

Furthermore, there is a correlation between the refractive index of the resin matrix and the refractive index of the particles, and the d-line refractive index of the particles is 2.5 or more and 3.2 or less, whereas the d-line refractive index of the resin matrix is 1.32 or more. It was found that the refractive index was highest at 1.42 or less. As shown in FIG. 3, when the refractive index of the resin 11 is high, the difference in the refractive index from the hollow particles 10 becomes small, and the amount of reflected light 2 with respect to the incident light 1 decreases. However, if the refractive index of the resin 11 becomes too low, the difference in the refractive index from the hollow particles 10 becomes too wide, and the light entering the hollow particles 10 repeats the reflection 12 in the particles. As a result, it is presumed that the light cannot be emitted to the resin 11 side and the light is confined, and the reflectance is conversely lowered. Therefore, the reflectance can be improved and the temperature reduction effect can be enhanced when the d-line refractive index of the particles is 2.5 or more and 3.2 or less and 1.32 or more and 1.42 or less of the resin matrix.

[Heat-shielding paint for optical equipment]
Hereinafter, the material composition of the heat-shielding paint of the present invention and the method for producing the heat-shielding paint of the present invention will be described.

<< Material composition >>
The thermal barrier coating material for optical instruments of the present invention contains pore-containing particles having an average particle size of 100 nm or less and a high refractive index of 2.5 or more and 3.2 or less in a solution of a resin dissolved in a solvent. Contains rate particles.

(Particles with a d-line refractive index of 2.5 or more and 3.2 or less (high-refractive index particles))
First, high-refractive index particles having a d-line refractive index of 2.5 or more and 3.2 or less in the present invention will be described.
For the high refractive index particles in the present invention, rutile-type titanium oxide and anatase-type titanium oxide can be used as the most suitable materials. When it is necessary to adjust the color, inorganic pigments such as chromium oxide, titanium, copper oxide, tungsten, platinum, iron oxide, and hematite, which absorb in the visible light region, and azo-based organic pigments can be used. .. However, as compared with titanium oxide having a low extinction coefficient in the visible light to infrared region, a material having a high extinction coefficient in the visible light region tends to have a slightly lower reflectance of sunlight. A higher reflectance of sunlight can be obtained by adjusting the particle size within the range of. One type of high-refractive index particles may be used alone, or a plurality of them may be mixed.

The high refractive index particles in the present invention have an average particle size of 2 μm or more and 5 μm or less. When the average particle size is less than 2 μm, the reflectance of sunlight decreases. Further, when the average particle size exceeds 5 μm, the unevenness of the film becomes large and the film thickness accuracy deteriorates.

Further, the surface of the high-refractive index particles in the present invention may be coated with an arbitrary organic material or inorganic material. Further, the shape may be irregular, spherical, flaky or hollow, but more preferably the shape has less surface irregularities.

The content of the total particles including the high refractive index particles and the pore-containing particles in the present invention is preferably 10% by weight or more and 90% by weight or less with respect to the heat-shielding paint. When the content of the particles is less than 10% by weight, the light reaching the base material increases, so that the reflectance due to sunlight decreases. Further, when the content of the particles exceeds 90% by weight, the brittleness of the coating film is deteriorated.

(Void-containing particles with an average particle size of 100 nm or less)
Next, particles having an average particle size of 100 nm or less in the present invention will be described.
In the present invention, as described above, the resin matrix is composed of pore-containing particles having an average particle size of 100 nm or less in the resin.

Since the pore-containing particles having an average particle size of 100 nm or less in the present invention are used for the purpose of lowering the refractive index of the resin, a material having a low refractive index is preferable. As an example, silica, MgF2, and an organic resin can be used. Preferably, hollow silica can be used.
The shape of the pore-containing particles having an average particle size of 100 nm or less in the present invention may include a porous structure as long as it is hollow.
The pore-containing particles having an average particle size of 100 nm or less in the present invention may be spherical, amorphous, or elliptical.

Either Sururia (JGC) or Sirinax (Nittetsu Mining Co., Ltd.) can be used for the hollow particles.

The average particle size of the pore-containing particles in the present invention is preferably 5 nm or more and 100 nm or less. It is technically difficult to adjust the average particle size of the hollow particles to less than 5 nm. Further, when the average particle size exceeds 100 nm, scattering occurs at the interface between the resin and the hollow particles, and the reflectance decreases.

The d-line refractive index of the resin matrix composed of the pore-containing particles having an average particle size of 100 nm or less and the resin in the present invention is preferably 1.32 or more and 1.42 or less. The range of the d-line refractive index is as described above, but when the d-line refractive index of the resin matrix composed of the pore-containing particles having an average particle size of 100 nm or less and the resin in the present invention is less than 1.32, the d-line refractive index is high with the resin. Since the difference in the refractive index of the refractive index particles is large, the refractive index decreases. Further, when the d-line refractive index of the resin matrix composed of the pore-containing particles having an average particle diameter of 100 nm or less and the resin exceeds 1.42, the refractive index is small because the difference in refractive index between the resin and the high refractive index particles is small. Decreases.

The pore ratio of the pore-containing particles having an average particle size of 100 nm or less in the present invention is preferably 10% by volume or more and 90% by volume or less. If the porosity is less than 10% by volume, it becomes difficult to reduce the d-line refractive index of the resin matrix to 1.42 or less. When the porosity exceeds 90% by volume, the strength of the particles decreases.

The content of the pore-containing particles having an average particle size of 100 nm or less in the present invention is preferably 5% by volume or more and 50% by volume or less with respect to all the components of the heat-shielding coating material excluding the solvent. When the content is less than 5% by volume, it is difficult to reduce the refractive index of the coating film. Further, if the content exceeds 50% by volume, the abrasion resistance of the coating film deteriorates.

(resin)
Next, the resin of the present invention will be described.
The resin in the present invention is an acrylic resin, a urethane resin, an epoxy resin, or a resin selected from a combination thereof, and a urethane acrylate resin is preferable.

Acrylic resins include Almatex 784 (Mitsui Chemicals), Almatex 785-5 (Mitsui Chemicals), Almatex 748-5M (Mitsui Chemicals), Metal Lock (Cemedine), Boncoat 40-418-EF (DIC), Boncoat. Any of CE-6400 (DIC) can be used.

As the urethane resin, any one of Adeka Polyether BPX-21 (ADECA), Adeka Polyether EDP-300 (Adeka), and Adeka New Ace V14-90 (ADECA) can be used. Further, as the urethane resin curing agent, any one of Takenate D110N (Mitsui Chemicals), D160N (Mitsui Chemicals), D120N (Mitsui Chemicals) and D140N (Mitsui Chemicals) can be used. The urethane resin and isocyanate as a curing agent can be mixed and used so that the equivalent ratio is 1: 1.

As the epoxy resin, any one of jER828 (Mitsubishi Chemical), jER1001 (Mitsubishi Chemical), 834X90 (Mitsubishi Chemical), EP-4100 (ADEKA), and EP-5100-75X (ADEKA) can be used. Further, as the epoxy resin curing agent, any one of Adeka Hardener H30 (Adeka), Adeka Hardener 6019 (Adeka), and Adeka Hardener EH-551CH (Adeka) can be used. The epoxy resin and the curing agent can be mixed and used so that the equivalent ratio is 1: 1.

Urethane acrylate resins include Olestar Q164 (Mitsui Chemicals), Olestar Q691 (Mitsui Chemicals), Olestar Q723 (Mitsui Chemicals), Orestar Q628 (Mitsui Chemicals), AH-600 (Kyoeisha Chemicals), 8965 (Yupika) Any of can be used. Further, as the curing agent for urethane acrylate, any one of Takenate D110N (Mitsui Chemicals), D160N (Mitsui Chemicals), D120N (Mitsui Chemicals), and D140N (Mitsui Chemicals) containing a urethane bond can be used. The acrylic resin and the curing agent can be mixed and used so that the equivalent ratio is 1: 1.

The pencil hardness of the resin is preferably H or more and 5H or less, and more preferably 1H or more and 3H or less. When the pencil hardness is less than H, the abrasion resistance deteriorates. Further, when the pencil hardness exceeds 5H, it becomes vulnerable to thermal shock. The content of the resin of the present invention is preferably 5% by weight or more and 50% by weight or less, and more preferably 7% by weight or more and 35% by weight or less with respect to the heat-shielding paint. If the content of the resin in the present invention is less than 5% by weight, the adhesion to the substrate deteriorates. Further, when the content of the resin in the present invention exceeds 50% by weight, the reflectance of sunlight deteriorates.

(solvent)
Next, the solvent will be described.
Any material may be used as the solvent. Examples of solvents include water, thinner, ethanol, isopropyl alcohol, n-butyl alcohol, ethyl acetate, propyl acetate, isobutyl acetate, butyl acetate, methyl ethyl ketone, methyl isobutyl ketone, propylene glycol monomethyl ether, toluene, xylene, acetone, cellosolve. , Glycol ethers, ethers and the like. These solvents may be used alone or in admixture of a plurality of types.

The preferable viscosity of the heat-shielding paint is 10 mPa · s or more and 10,000 mPa · s or less. If the viscosity of the heat-shielding paint is less than 10 mPa · s, the film thickness of the heat-shielding film after coating may become thin. Further, when it is larger than 10000 mPa · s, the coatability of the heat-shielding paint is lowered.

(Additive)
The thermal barrier coating material of the present invention may contain any other additive. Examples include dispersants, hardeners, hardeners, plasticizers, thixophilic agents, leveling agents, infrared transmissive organic colorants, infrared transmissive inorganic colorants, preservatives, UV absorbers, antioxidants, etc. Examples thereof include a coupling agent, inorganic particles and organic particles having a d-line refractive index of 2.5 or less, and inorganic particles having a d-line refractive index of 3.2 or more.
Dispersants are DISPERBYK-118 (Big Chemie Japan), DISPERBYK-110 (Big Chemie Japan), DISPERBYK-111 (Big Chemie Japan), DISPERBYK-102 (Big Chemie Japan), DISPERBYK-190 (Big Chemie Japan), DISPERBYK You can use any of -106 (Big Chemie Japan), DISPERBYK-180 (Big Chemie Japan), DISPERBYK-108 (Big Chemie Japan), and Demor EP (Kao).

<< Manufacturing method of heat-shielding paint >>
The method for producing the thermal barrier coating material of the present invention will be described below.
As a method for producing the heat-shielding coating material of the present invention, high-refractive index particles having a d-line refractive index of 2.5 or more and 3.2 or less and pore-containing particles having an average particle size of 100 nm or less can be dispersed in the coating material. Any method can be used. Examples include bead mills, ball mills, jet mills, three rollers, planetary rotating devices, mixers, ultrasonic dispersers, and the like.

[Heat shield film for optical equipment]
The material structure and film structure of the heat shield film of the present invention will be described below.
<< Material composition >>
The material composition of the heat shield film for the optical device of the present invention will be described below.
The heat-shielding film of the present invention contains high-refractive index particles having a d-line refractive index of 2.5 or more and 3.2 or less, pore-containing particles having an average particle size of 100 nm or less, and a resin.

(High-refractive index particles with a d-line refractive index of 2.5 or more and 3.2 or less)
In the heat shield film formed by applying the heat shield paint, the content of high refractive index particles having a d-line refractive index of 2.5 or more and 3.2 or less in the present invention is 20 volumes with respect to the heat shield film. The ratio is preferably% or more and 60% by volume or less. When the content of the high-refractive index particles is less than 20% by volume, the light reaching the base material increases, so that the reflectance due to sunlight decreases. Further, when the content of the high refractive index particles exceeds 60% by volume, the brittleness of the coating film is deteriorated.

(Void-containing particles with an average particle size of 100 nm or less)
The content of the pore-containing particles having an average particle size of 100 nm or less in the above-mentioned invention with respect to the heat-shielding film is preferably 5% by volume or more and 50% by volume or less. When the content is less than 5% by volume, it is difficult to reduce the refractive index of the coating film. Further, if the content exceeds 50% by volume, the abrasion resistance of the coating film deteriorates.

(resin)
The content of the resin with respect to the heat shield film is preferably 10% by volume or more and 75% by volume or less, and more preferably 20% by volume or more and 70% by volume or less. If the content of the resin in the present invention is less than 10% by volume, the adhesion to the substrate deteriorates. Further, when the content of the resin in the present invention exceeds 78% by volume, the reflectance of sunlight deteriorates.

(Additive)
The thermal barrier coating material of the present invention may contain any other additive as a part of the resin matrix as long as the d-line refractive index of the resin matrix is within the range of 1.32 or more and 1.42 or less. Examples include dispersants, hardeners, hardeners, plasticizers, thixophilic agents, leveling agents, infrared transmissive organic colorants, infrared transmissive inorganic colorants, preservatives, UV absorbers, antioxidants, etc. Examples thereof include a coupling agent, inorganic particles and organic particles having a d-line refractive index of 2.5 or less, and inorganic particles having a d-line refractive index of 3.2 or more.

<< Membrane composition >>
The heat shield film 9 of the present invention is formed at least outside the base material 5. As the form thereof, it may be in close contact with the base material 5, or a primer layer for improving the adhesion may be provided between the base material 5 and the heat shield film 9.

(Base material)
Any material can be used as the base material, but metal and plastic are preferable. Examples of the metal material include aluminum, titanium, stainless steel, magnesium alloy and the like. Examples of plastic materials include polycarbonate resin, acrylic resin, ABS resin, fluororesin and the like.

The film thickness of the base material can be any thickness, but is preferably 0.5 mm or more and 5 mm or less, more preferably 0.5 mm or more and 2 mm or less. If the film thickness is less than 0.5 mm, it is difficult to maintain the shape of the lens barrel. Further, if the film thickness exceeds 5 mm, the cost of the member increases.

(Primer layer)
Any material can be used for the primer layer, and examples thereof include epoxy resin, urethane resin, acrylic resin, silicone resin, and fluororesin. Further, in the primer layer, particles of the present invention or particles other than the present invention, colorants, dispersants, curing agents, curing catalysts, plasticizers, texo-imparting agents, leveling agents, organic colorants, inorganic colorants, preservatives , UV absorbers, antioxidants, coupling agents, solvent residues may be included.

The thickness of the primer layer is preferably 2 μm or more and 30 μm or less, and more preferably 5 μm or more and 20 μm or less. If the film thickness is less than 2 μm, the adhesion of the film may decrease, and if it exceeds 30 μm, the film thickness accuracy may be adversely affected.

(Film thickness of the heat shield film of the present invention)
The average film thickness of the heat shield film of the present invention is preferably 10 μm or more and 70 μm or less. When the film thickness is less than 10 μm, light is transmitted to the base material side and the reflectance of sunlight deteriorates. If the film thickness exceeds 70 μm, the film thickness accuracy deteriorates. The average film thickness is preferably ± 10 μm with respect to the standard value.

<< Method for Forming Heat Shielding Film of the Present Invention >>
As the heat-shielding film of the present invention, any coating method and effect method can be used as long as the heat-shielding coating film of the present invention can be uniformly applied so as to have an average film thickness of preferably 10 μm or more and 70 μm or less.

Examples of the method for applying the heat shield film for the optical device of the present invention include brush coating, spray coating, dip coating, transfer and the like. Further, the heat shield film may be coated in one layer or in multiple layers, and may be textured in order to give a design property.

Further, as a method for curing the heat-shielding film for an optical device of the present invention, the film may be left at room temperature, the curing may be promoted by arbitrary heat, or ultraviolet rays may be applied. Examples of the method of applying heat to cure include a heating furnace, a heater, infrared heating and the like. The curing temperature is preferably room temperature to 400 ° C., more preferably room temperature to 200 ° C.

[Example]
Hereinafter, suitable examples of the present invention will be described.
The preparation of the heat-shielding paint, the preparation of the heat-shielding film, the evaluation of the reflectance, the evaluation of the temperature, the pencil hardness, and the evaluation of the film thickness accuracy in Examples 1 to 13 were carried out as follows.

<Measurement method of reflectance>
As shown in FIG. 4, the reflectance was measured using a spectrophotometer (U-4000; Hitachi High-Tech).
For the sample for measurement, the heat shield film of the present invention was formed on a metal plate measuring 30 mm square and having a thickness of 1 mm. For the metal plate, any one of stainless steel, aluminum, titanium, magnesium alloy and the like was used. Further, the surface of the metal plate was coated with the heat-shielding film of the present invention so as to have a desired film thickness with a spin coater, and fired.

Next, a method of measuring the reflectance will be described. As shown in FIG. 4, incident light 1 having a wavelength of 400 nm to 2600 nm was incident on the integrating sphere 13. First, a test piece whose angle of incidence was tilted by 5 ° with respect to the incident light 1 was placed on a blank of an alumina sintered body in which 100% reflection occurs at the test piece mounting portion 14, and baseline measurement was performed. Subsequently, a test piece having the light-shielding film of the present invention formed was placed on the test piece attachment portion 14 instead of the blank, and light of 400 nm to 2600 nm was incident on the test piece, and the light was detected by the detector 15 to measure the reflectance. Further, as the reflectance, the value of the average reflectance at intervals of 1 nm in the range of 400 nm to 2600 nm is described. The reflectance has a correlation with the temperature evaluation result, and when it is 90% or more, a good value is shown in the following temperature evaluation result. From this, it can be said that a good heat-shielding film has a reflectance of 90% or more.

<Evaluation method of temperature reduction effect>
FIG. 5 is a schematic diagram showing a temperature evaluation method. As shown in FIG. 5, a lamp 16, a temperature measuring jig 19, and a temperature evaluation test piece 17 were used for temperature measurement.

For the test piece 17 for temperature evaluation, the heat shield film of the present invention was formed on a metal plate measuring 100 mm square and having a thickness of 1 mm. For the metal plate, any one of stainless steel, aluminum, titanium, magnesium alloy and the like was used. Further, the surface of the metal plate was coated with the heat-shielding film of the present invention so as to have a desired film thickness with a spin coater, and fired. The temperature measuring jig 19 was made of corrugated cardboard having a white surface and having a size of 120 mm × 120 mm × 120 mm, and a 90 mm × 90 mm square window portion was provided at the attachment portion of the test piece 17 for temperature evaluation.
Further, Hilux MT150FD6500K (Iwasaki Electric) was used for the lamp 16.

Next, the temperature evaluation test piece 17 was attached to the temperature measurement jig 19, and the thermocouple was attached to the back surface of the temperature evaluation test piece 17. A temperature measuring jig 19 to which the temperature evaluation test piece 17 was attached was installed so that the distance from the lamp 16 was 100 mm. Next, the lamp 16 was irradiated for 60 minutes, and the temperature after 60 minutes was measured.

The temperature reduction effect was obtained by forming a black blank on the surface of the test piece 17 for temperature evaluation, measuring the temperature, and calculating the difference from the temperature measurement result of the heat shield film of the example to obtain the temperature heat shield effect.

As a black blank, a paint obtained by mixing 20 g of carbon black (MA100; Mitsubishi Chemical), 100 g of epoxy resin (jER828; Mitsubishi Chemical), 70 g of amine curing agent (ST11; Mitsubishi Chemical), and 20 g of thinner with a planetary rotating device is used for temperature evaluation. Was applied to the surface of the test piece 17 and fired to prepare the test piece 17.

When the temperature reduction effect was 10 ° C. or higher, it was evaluated as a good heat shield film (table below: good). If the temperature reduction effect is less than 10 ° C, the heat shield film is not good (table below: defective).

<Evaluation method of film thickness accuracy>
The method for evaluating the film thickness accuracy will be described below. Optical equipment has strict position accuracy, but if the film thickness accuracy varies, the position accuracy deteriorates. For the sample for film thickness accuracy evaluation, the heat shield film of the present invention was applied by spraying to a metal plate having a thickness of 1 mm and a film thickness accuracy of the present invention so as to have a desired film thickness, and the sample was fired. Twenty samples for evaluation were prepared, and the film thickness was measured at five locations with a micrometer for each sample, and the average value was calculated and used as the film thickness. Further, the average value of the film thicknesses of the 20 test pieces was calculated, and the maximum amount of deviation from the average value was used as the value of the film thickness variation. The maximum amount of deviation was defined as the maximum amount of deviation for a total of 100 locations with 20 test pieces x 5 locations.

If the film thickness variation was within ± 10 μm, it was evaluated as a good heat shield film (table below: good). If the film thickness variation exceeds ± 10 μm, the position accuracy deteriorates and it becomes difficult to use it as an optical device (table below: defective).

<Evaluation method of pencil hardness>
The evaluation method of pencil hardness will be described below. For the sample for film thickness accuracy evaluation, the heat shield film of the present invention was applied by spray to a metal plate having a thickness of 30 mm square and a thickness of 1 mm so as to have a desired film thickness, and fired. If the pencil hardness is H or higher, it can be said that it is a good heat shield film. Therefore, Mitsubishi Pencil Hi-Uni H was used as the test pencil, and the centering was performed vertically with # 400 sandpaper. The pressing angle of the pencil was 45 °, and a pressure of 10 N was applied to move the pencil a distance of 10 mm. The number of tests was 5, and the heat-shielding film without any scratches (table below: good (pencil hardness H or higher)) and the film with scratches or peeling (table below: poor (pencil hardness H or lower)). did.

(Example 1)
<Preparation of heat shield paint>
In Example 1, a heat-shielding paint was produced by the following method. Titanium oxide (HT0210 (Toho Titanium; average particle size 2 μm)) 210 g, acrylic resin 35 g (Almatex 784 (Mitsui Chemicals)), hollow silica 100 g (Sulsia (Nikki): 50% porosity), dispersant 2.4 g (DISPERBYK-180 (Big Chemie Japan)), 30 g of solvent (butyl acetate) was weighed and stirred with a planetary rotating device (Kentaro Awatori; Shinky) for 10 minutes to obtain the thermal barrier coating material of Example 1. ..

<Making a heat shield film>
In Example 1, a heat shield film was prepared by the following method under the materials and conditions shown in Table 1. The above heat-shielding paint was applied to a test piece for reflectance measurement, a test piece 17 for temperature evaluation, and a test piece for film thickness accuracy evaluation so that the film thickness was 40 μm, and cured at 130 ° C. for 1 hour. The heat shield film of Example 1 was obtained.

(Examples 2 to 13)
In Examples 2 to 13, a heat shield film was prepared in the same manner as in Example 1 except that the materials and conditions shown in Tables 1 to 3 were used.
As for titanium oxide, hollow silica, and urethane acrylate, the same ones were used in all Examples and Comparative Examples.

Titanium oxide having an average particle size of 5 μm was prepared by drying titanium oxide having a particle size of 80 nm at a low temperature with a rotary kiln, firing at a temperature of 1100 ° C. for 2 hours, and pulverizing. JR-1000 (Taika) was used as the particles having an average particle size of 1 μm.

<Evaluation results>
The results of evaluating the reflectance and temperature reducing effect of the heat shield films of Examples 1 to 13 by the above method are shown in Tables 4 to 6.

As a result of the measurement, the reflectance of the heat shield film is preferably 90% or more. Further, the temperature reduction effect preferably has a difference of 10 ° C. or more from the blank. Moreover, the pencil hardness is preferably H or more. Further, the film thickness accuracy is preferably within ± 10 μm.

In Example 1, titanium oxide having an average particle size of 2 μm, an acrylic resin, and hollow silica were used, and the refractive index of the resin matrix composed of the acrylic resin and hollow silica was adjusted to 1.41. Table 4 shows the results of evaluating the reflectance, temperature reduction effect, pencil hardness, and film thickness accuracy of the obtained heat shield film. The evaluation result of the reflectance was 97%, which was good. Moreover, the temperature reduction effect was good as it was 10 ° C. or higher. The pencil hardness was H or higher, which was good. Moreover, the evaluation result of the film thickness accuracy was within ± 10 μm, which was good.

In Example 2, a urethane resin (Adeka Polyester BPX-21 (Adeka)) was used with respect to Example 1. Table 4 shows the results of evaluating the reflectance, temperature reduction effect, pencil hardness, and film thickness accuracy of the obtained heat shield film. The evaluation result of the reflectance was 97%, which was good. Moreover, the temperature reduction effect was good as it was 10 ° C. or higher. The pencil hardness was H or higher, which was good. Moreover, the evaluation result of the film thickness accuracy was within ± 10 μm, which was good.

In Example 3, an epoxy resin (iER828 (Mitsubishi Chemical Corporation)) was used with respect to Example 1. Table 4 shows the results of evaluating the reflectance, temperature reduction effect, pencil hardness, and film thickness accuracy of the obtained heat shield film. The evaluation result of the reflectance was 95%, which was good. Moreover, the temperature reduction effect was good as it was 10 ° C. or higher. The pencil hardness was H or higher, which was good. Moreover, the evaluation result of the film thickness accuracy was within ± 10 μm, which was good.

In Example 4, urethane acrylate (Olestar Q691 (Mitsubishi Chemical Corporation)) was used with respect to Example 1. Table 4 shows the results of evaluating the reflectance, temperature reduction effect, pencil hardness, and film thickness accuracy of the obtained heat shield film. The evaluation result of the reflectance was 98%, which was good. Moreover, the temperature reduction effect was good as it was 10 ° C. or higher. The pencil hardness was H or higher, which was good. Moreover, the evaluation result of the film thickness accuracy was within ± 10 μm, which was good.

In Example 5, urethane acrylate (Orestar Q691 (Mitsubishi Chemical Corporation)) was used as compared with Example 1, and a heat-shielding film in which the d-line refractive index of the resin matrix was adjusted to 1.32 was used. Table 4 shows the results of evaluating the reflectance, temperature reduction effect, pencil hardness, and film thickness accuracy of the obtained heat shield film. The evaluation result of the reflectance was 94%, which was good. Moreover, the temperature reduction effect was good as it was 10 ° C. or higher. The pencil hardness was H or higher, which was good. Moreover, the evaluation result of the film thickness accuracy was within ± 10 μm, which was good.

In Example 6, urethane acrylate (Orestar Q691 (Mitsubishi Chemical Corporation)) was used as compared with Example 1, and a heat-shielding film in which the d-line refractive index of the resin matrix was adjusted to 1.30 was used. Table 5 shows the results of evaluating the reflectance, temperature reduction effect, pencil hardness, and film thickness accuracy of the obtained heat shield film. The evaluation result of the reflectance was 94%, which was good. Moreover, the temperature reduction effect was good as it was 10 ° C. or higher. The pencil hardness was H or higher, which was good. Moreover, the evaluation result of the film thickness accuracy was within ± 10 μm, which was good. However, when the film thickness was set to 200 μm or more and a temperature impact was applied, film cracking sometimes occurred.

In Example 7, urethane acrylate (Orestar Q691 (Mitsubishi Chemical Corporation)) was used as compared with Example 1, and a heat-shielding film in which the d-line refractive index of the resin matrix was adjusted to 1.48 was used. Table 5 shows the results of evaluating the reflectance, temperature reduction effect, pencil hardness, and film thickness accuracy of the obtained heat shield film. The evaluation result of the reflectance was 91%, which was good although it was slightly inferior. Moreover, the temperature reduction effect was good as it was 10 ° C. or higher. The pencil hardness was H or higher, which was good. Moreover, the evaluation result of the film thickness accuracy was within ± 10 μm, which was good.

In Example 8, titanium oxide having an average particle size of 5 μm was used and urethane acrylate (Orestar Q691 (Mitsubishi Chemical)) was used as compared with Example 1, and the d-line refractive index of the resin matrix was adjusted to 1.39. .. Table 5 shows the results of evaluating the reflectance, temperature reduction effect, pencil hardness, and film thickness accuracy of the obtained heat shield film. The evaluation result of the reflectance was 95%, which was good. Moreover, the temperature reduction effect was good as it was 10 ° C. or higher. The pencil hardness was H or higher, which was good. Further, although some irregularities were generated on the surface, the evaluation result of the film thickness accuracy was within ± 10 μm, which was good.

In Example 9, compared to Example 1, titanium oxide having an average particle size of 1 μm and titanium oxide having an average particle size of 2 μm were used in combination, and urethane acrylate (Olestar Q691 (Mitsubishi Chemical)) was used to form a resin matrix d. The linear refractive index was adjusted to 1.39. Table 5 shows the results of evaluating the reflectance, temperature reduction effect, pencil hardness, and film thickness accuracy of the obtained heat shield film. The evaluation result of the reflectance was 95%, which was good. Moreover, the temperature reduction effect was good as it was 10 ° C. or higher. The pencil hardness was H or higher, which was good. Moreover, the evaluation result of the film thickness accuracy was within ± 10 μm, which was good.

In Example 10, the content of titanium oxide having an average particle size of 2 μm was adjusted to 22% by volume with respect to Example 1, and urethane acrylate (Orestar Q691 (Mitsubishi Chemical)) was used to refract the d-line of the resin matrix. The rate was adjusted to 1.39. Table 5 shows the results of evaluating the reflectance, temperature reduction effect, pencil hardness, and film thickness accuracy of the obtained heat shield film. The evaluation result of the reflectance was 95%, which was good. Moreover, the temperature reduction effect was good as it was 10 ° C. or higher. The pencil hardness was H or higher, which was good. Moreover, the evaluation result of the film thickness accuracy was within ± 10 μm, which was good.

In Example 11, the content of titanium oxide having an average particle size of 2 μm was adjusted to 59% by volume with respect to Example 1, and urethane acrylate (Orestar Q691 (Mitsubishi Chemical)) was used to refract the d-line of the resin matrix. The rate was adjusted to 1.39. Table 6 shows the results of evaluating the reflectance, temperature reduction effect, pencil hardness, and film thickness accuracy of the obtained heat shield film. The evaluation result of the reflectance was 98%, which was good. Moreover, the temperature reduction effect was good as it was 10 ° C. or higher. The pencil hardness was H or higher, which was good. Moreover, the evaluation result of the film thickness accuracy was within ± 10 μm, which was good.

In Example 12, the content of titanium oxide having an average particle size of 2 μm was adjusted to 20% by volume with respect to Example 1, and urethane acrylate (Orestar Q691 (Mitsubishi Chemical)) was used to refract the d-line of the resin matrix. The rate was adjusted to 1.39. Table 6 shows the results of evaluating the reflectance, temperature reduction effect, pencil hardness, and film thickness accuracy of the obtained heat shield film. The evaluation result of the reflectance was 94%, which was good. Moreover, the temperature reduction effect was good as it was 10 ° C. or higher. The pencil hardness was H or higher, which was good. Moreover, the evaluation result of the film thickness accuracy was within ± 10 μm, which was good.

In Example 13, the content of titanium oxide having an average particle size of 2 μm was adjusted to 60% by volume with respect to Example 1, and urethane acrylate (Orestar Q691 (Mitsubishi Chemical)) was used to refract the d-line of the resin matrix. The rate was adjusted to 1.39. Table 6 shows the results of evaluating the reflectance, temperature reduction effect, pencil hardness, and film thickness accuracy of the obtained heat shield film. The evaluation result of the reflectance was 98%, which was good. Moreover, the temperature reduction effect was good as it was 10 ° C. or higher. The pencil hardness was H or higher, which was good. Moreover, the evaluation result of the film thickness accuracy was ± 10 μm or less, which was good. However, when the film thickness is set to 200 μm or more and a temperature impact is applied, the film may crack due to the large amount of the inorganic pigment of titanium oxide.

[Comparative Examples 1 to 7]
Adjustment of the heat-shielding paint for comparison, preparation of the heat-shielding film, evaluation of reflectance, evaluation of temperature reduction effect, evaluation of film thickness accuracy, and evaluation of pencil hardness were carried out in the same manner as in Examples 1 to 13 described above. It was. The differences from Examples 1 to 13 are shown below.

As fluorine-based resins, Poly (2,2,3,3-tetrafluoropropylryl) (Aldrich), Poly (2,2,3,3-tetrafluoropropyl acrylate) (Aldrich), Poly (2,2,2-trifluoroethylcrylic) ) (Aldrich) or Zeffle (Daikin) can be used.
As zinc oxide, zinc oxide particles #F (Sakai Chemical Co., Ltd.) having an average particle size of 3.8 μm were used.
As the silicon particles, silicon SIE23PB (high-purity chemistry) having an average particle size of 5 μm was used.
Titanium oxide having an average particle size of 7 μm was prepared by drying titanium oxide having a particle size of 80 nm with a rotary kiln at a low temperature, firing at a temperature of 1100 ° C. for 2 hours, and pulverizing the mixture.
Crosslinked styrene acrylic hollow particles (primary particle size 300 nm; Adachi Shinsangyo) were used as the hollow particles having an average particle size of 100 nm or more.

Tables 7 and 8 show the materials constituting the heat shield films of Comparative Examples 1 to 7 and the amount of addition.
Tables 9 and 10 show the results of evaluation using the heat shield films of Comparative Examples 1 to 7, respectively.
In Comparative Example 1, a fluororesin (Zefle (Daikin)) having a lower coating film hardness than that of Example 1 was used. Table 9 shows the results of evaluating the reflectance, temperature reduction effect, pencil hardness, and film thickness accuracy of the obtained heat shield film. The evaluation result of the reflectance was 95%, which was good. Moreover, the temperature reduction effect was good as it was 10 ° C. or higher. The pencil hardness was less than H, and the hardness was insufficient. Moreover, the evaluation result of the film thickness accuracy was within ± 10 μm, which was good.

In Comparative Example 2, titanium oxide having an average particle size of 1 μm and a small particle size was used as compared with Example 1. Table 9 shows the results of evaluating the reflectance, temperature reduction effect, pencil hardness, and film thickness accuracy of the obtained heat shield film. The evaluation result of the reflectance was 83%, which was less than the reflectance of 90%. Further, the temperature reduction effect was less than 10 ° C., and the effect was low. The pencil hardness was H or higher, which was good. Moreover, the evaluation result of the film thickness accuracy was within ± 10 μm, which was good.

In Comparative Example 3, zinc oxide having a d-line refractive index of 2 and a low refractive index was used as compared with Example 1. Table 9 shows the results of evaluating the reflectance, temperature reduction effect, pencil hardness, and film thickness accuracy of the obtained heat shield film. The evaluation result of the reflectance was 78%, which was less than the reflectance of 90%. Further, the temperature reduction effect was less than 10 ° C., and the effect was low. The pencil hardness was H or higher, which was good. Moreover, the evaluation result of the film thickness accuracy was within ± 10 μm, which was good.

In Comparative Example 4, silicon having a high refractive index with a d-line refractive index of 4 was used as compared with Example 1. Table 9 shows the results of evaluating the reflectance, temperature reduction effect, pencil hardness, and film thickness accuracy of the obtained heat shield film. The evaluation result of the reflectance was 75%, which was less than the reflectance of 90%. Further, the temperature reduction effect was less than 10 ° C., and the effect was low. The pencil hardness was H or higher, which was good. Moreover, the evaluation result of the film thickness accuracy was within ± 10 μm, which was good.

In Comparative Example 5, titanium oxide having an average particle size of 7 μm and a large particle size was used as compared with Example 1. Table 9 shows the results of evaluating the reflectance, temperature reduction effect, pencil hardness, and film thickness accuracy of the obtained heat shield film. The evaluation result of the reflectance was 94%, which was good. Moreover, the temperature reduction effect was good at 10 ° C. or higher. The pencil hardness was H or higher, which was good. However, the evaluation result of film thickness accuracy exceeded ± 10 μm, which was bad.

In Comparative Example 6, hollow particles having an average particle size of 100 nm or more (crosslinked styrene acrylic hollow particles (primary particle size 300 nm; Adachi Shinsangyo)) were used as compared with Example 1. Table 10 shows the results of evaluating the reflectance, temperature reduction effect, pencil hardness, and film thickness accuracy of the obtained heat shield film. The evaluation result of the reflectance was 88%, which was less than the reflectance of 90%. Further, the temperature reduction effect was less than 10 ° C., and the effect was low. The pencil hardness was H or higher, which was good. Moreover, the evaluation result of the film thickness accuracy was less than ± 10 μm, which was good.

In Comparative Example 7, solid particles were used as particles having an average particle size of 100 nm or less as compared with Example 1. Table 10 shows the results of evaluating the reflectance, temperature reduction effect, pencil hardness, and film thickness accuracy of the obtained heat shield film. The evaluation result of the reflectance was 83%, which was less than the reflectance of 90%. Further, the temperature reduction effect was less than 10 ° C., and the effect was low. The pencil hardness was H or higher, which was good. Moreover, the evaluation result of the film thickness accuracy was within ± 10 μm, which was good.

The light-shielding film for optical equipment of the present invention can be used for members and precision equipment used outdoors.

1. 1. Incident light 2. Reflected light 3. Transmitted light 4. Infrared reflective film
5. Base material 6. Lens 7. Fitting part 8. Lens barrel 9. Heat shield film 10. Particles 11. Resin 12. Reflection in particles 13. Integrating sphere 14. Specimen mounting part 15. Detector 16. Lamp 17. Test piece for temperature evaluation 18. Temperature measurement point 19. Temperature measurement jig

Claims (29)

An optical device having a lens and a lens barrel having the lens inside the lens barrel.
A heat shield film is provided on at least a part of the outer peripheral surface of the lens barrel.
The heat shield film contains first particles having a d-line refractive index of 2.5 or more and 3.2 or less in a resin selected from urethane resin, acrylic resin, epoxy resin, and a combination thereof. An optical instrument comprising a second particle having an average particle diameter of 5 nm or more and 100 nm or less, and a pore due to the second particle. The optical device according to claim 1, wherein the first particles have an average particle size of 2 μm or more and 5 μm or less. The optical device according to claim 1 or 2, wherein the first particles are contained in a proportion of 20% by volume or more and 60% by volume or less with respect to the heat shield film. The optical device according to any one of claims 1 to 3, wherein the first particle is made of titanium oxide. The optical device according to any one of claims 1 to 4, wherein the second particle is a hollow particle. The optical device according to any one of claims 1 to 5, wherein the second particle is silica. The optical device according to any one of claims 1 to 6, wherein the second particles are contained in a proportion of 5% by volume or more and 50% by volume or less with respect to the heat shield film. The optical device according to any one of claims 1 to 7, wherein the pencil hardness of the resin is H or more and 5H or less. The optical device according to any one of claims 1 to 8, wherein the heat shield film has an average film thickness of 10 μm or more and 70 μm or less. In the resin selected from urethane resin, acrylic resin, epoxy resin, and a combination thereof, first particles having a d-line refractive index of 2.5 or more and 3.2 or less and an average particle size of 5 nm. A heat-shielding film comprising a second particle having a diameter of 100 nm or more and a pore due to the second particle. The heat shield film according to claim 10, wherein the first particles have an average particle size of 2 μm or more and 5 μm or less. The heat shield film according to claim 10 or 11, wherein the first particles are contained in a ratio of 20% by volume or more and 60% by volume or less with respect to the heat shield film. The heat-shielding film according to any one of claims 10 to 12, wherein the first particles are made of titanium oxide. The heat shield film according to any one of claims 10 to 13, wherein the second particle is a hollow particle. The heat-shielding film according to any one of claims 10 to 14, wherein the second particle is silica. The heat shield film according to any one of claims 10 to 15, wherein the second particles are contained in a ratio of 5% by volume or more and 50% by volume or less with respect to the heat shield film. The heat-shielding film according to any one of claims 10 to 16, wherein the pencil hardness of the resin is H or more and 5H or less. The heat shield film according to any one of claims 10 to 17, which has an average film thickness of 10 μm or more and 70 μm or less. In a solution prepared by dissolving a resin selected from urethane resin, acrylic resin, epoxy resin, and a combination thereof in a solvent, the first particles having a d-line refractive index of 2.5 or more and 3.2 or less A heat-shielding coating material comprising a second particle having an average particle size of 5 nm or more and 100 nm or less, and pores formed by the second particle. The heat-shielding coating material according to claim 19, wherein the first particles have an average particle size of 2 μm or more and 5 μm or less. A first particle having a d-line refractive index of 2.5 or more and 3.2 or less in a solution prepared by dissolving a resin selected from urethane resin, acrylic resin, epoxy resin, and a combination thereof in a solvent. An optical instrument comprising a step of applying a heat-shielding paint containing a second particle having an average particle size of 5 nm or more and 100 nm or less and pores formed by the second particle to form a heat-shielding film. How to manufacture the equipment. The method for manufacturing an optical instrument according to claim 21, wherein the first particles have an average particle size of 2 μm or more and 5 μm or less. The method for manufacturing an optical instrument according to claim 21 or 22, wherein the first particles are contained in a proportion of 20% by volume or more and 60% by volume or less with respect to the heat shield film. The method for manufacturing an optical instrument according to any one of claims 21 to 23, wherein the first particle is made of titanium oxide. The method for manufacturing an optical instrument according to any one of claims 21 to 24, wherein the second particle is a hollow particle. The method for manufacturing an optical instrument according to any one of claims 21 to 25, wherein the second particle is silica. The method for manufacturing an optical instrument according to any one of claims 21 to 26, wherein the second particles are contained in a proportion of 5% by volume or more and 50% by volume or less with respect to the heat shield film. The method for manufacturing an optical instrument according to any one of claims 21 to 27, wherein the pencil hardness of the resin is H or more and 5H or less. The method for manufacturing an optical device according to any one of claims 21 to 28, wherein the heat shield film has an average film thickness of 10 μm or more and 70 μm or less.

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