JP2017194632A - Heat-blocking film, heat-blocking paint, and optical instrument - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat-blocking film that has a high reflectance despite its thinness, minimizes an increase in temperature due to the sunlight, has high accuracy of thin film, and has high wear resistance, a heat-blocking paint, and an optical instrument including such a heat-blocking film.SOLUTION: There is provided a heat-blocking film having high-refractive index particles having a d-line refractive index of 2.5 or more and 3.2 or less dispersed in a resin matrix, wherein the resin matrix contains pore-containing particles having an average particle diameter of 100 nm or less in a resin selected from a urethane resin, acrylic resin, epoxy resin, and combination of these, and the high-refractive index particles have an average particle diameter of 2 μm or more and 5 μm or less.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a thermal barrier film, a thermal barrier paint that may be used outdoors, and an optical apparatus having such a thermal barrier film.

  The thermal barrier 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 for suppressing the temperature rise of a member due to sunlight, a method is known in which incident light 1 due to the sun is reflected as reflected light 2 by an infrared reflecting film 4 as shown in FIG. By increasing the ratio of the reflected light 2 to the incident light 1, heat generation by the transmitted light 3 can be suppressed. As other heat shielding methods, there are a method of providing a heat insulating layer having a low thermal conductivity instead of the infrared reflecting film 4, a heat radiating layer for releasing heat to the outside, or a combination thereof.

  On the other hand, since the thermal barrier film is a member that may be touched by human hands, wear resistance is required to withstand contact from the outside in addition to the function of suppressing the temperature rise. In addition, when used in an optical apparatus, it is necessary to adjust the focus, so position accuracy is important. For example, as shown in FIG. 2, the lens barrel of the optical apparatus includes a lens 6 and its lens barrel 8 and the like, and is provided with a sliding fitting portion 7 for adjusting the focus. By providing the thermal barrier 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 such as the focal point can be maintained. Therefore, it is necessary to control the film thickness variation of the coating film for precision instruments such as optical instruments.

Patent Document 1 discloses a film made of a colored layer, an infrared reflecting layer, and a heat insulating layer in a thermal barrier film for a lens barrel. 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 thermal barrier film having improved wear resistance by adding selben having a particle size of 0.1 to 0.4 mm to a synthetic resin emulsion.

JP 2009-139856 A Japanese Patent Laying-Open No. 2015-81303

However, when 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 obtain sufficient positional accuracy of the sliding fitting portion.
In addition, when Serben 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 background art, and a heat-shielding film and a heat-shielding film that have high reflectivity 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 apparatus having such a thermal barrier film.

An optical apparatus of the present invention is an optical apparatus having a lens and a lens barrel provided with the lens inside a lens barrel,
A thermal barrier film on at least a part of the outer peripheral surface of the lens barrel;
The thermal barrier film is a thermal barrier film in which high refractive index particles having a d-line refractive index of 2.5 to 3.2 are dispersed in a resin matrix, and the resin matrix includes a urethane resin, an acrylic resin, an epoxy resin. A resin selected from a resin and a combination thereof includes pore-containing particles having an average particle size of 100 nm or less, and the average particle size of the high refractive index particles is from 2 μm to 5 μm.
The thermal barrier film of the present invention is a thermal barrier film in which high refractive index particles having a d-line refractive index of 2.5 or more and 3.2 or less are dispersed in a resin matrix, and the resin matrix is a urethane resin or an acrylic resin. A resin selected from an epoxy resin and a combination thereof includes pore-containing particles having an average particle diameter of 100 nm or less, and the average particle diameter of the high refractive index particles is 2 μm or more and 5 μm or less. Features.

  The thermal barrier paint of the present invention comprises pore-containing particles having an average particle size of 100 nm or less, d-line refraction in a solution obtained by dissolving a resin selected from urethane resin, acrylic resin, epoxy resin and combinations thereof in a solvent. And a thermal barrier coating containing high refractive index particles having a refractive index of 2.5 or more and 3.2 or less and an average particle diameter of 2 μm or more and 5 μm or less.

  According to the present invention, a thermal barrier film, a thermal barrier coating, and an optical apparatus having such a thermal barrier film that have a high reflectance even in a thin film, have a low temperature rise due to sunlight, have high film thickness accuracy, and high wear resistance. Can be provided.

It is a cross-sectional schematic diagram which shows the state of reflection and absorption of sunlight when an infrared reflective film is formed on the upper surface of a substrate. It is a cross-sectional schematic diagram of a lens barrel. It is a cross-sectional schematic diagram which shows reflection of particle | grains and a resin interface. It is a measurement form schematic diagram 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 thermal barrier coating of the present invention for improving the reflectance of sunlight, the thermal barrier film, and the optical apparatus having such a thermal barrier film will be described.
The optical apparatus of the present invention is an optical apparatus having a lens and a lens barrel provided with the lens inside a lens barrel, and has a heat shielding 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 containing pore-containing particles having an average particle diameter of 100 nm or less in a resin selected from a urethane resin, an acrylic resin, an epoxy resin, and a combination thereof. The “pore-containing particle” refers to a particle having a hollow structure or a porous structure. “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 diameter” is a diameter converted from the volume of the particle, and is determined by a laser diffraction particle size distribution meter.
The median diameter was used as the “average particle diameter” in the present invention.

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

  The range of 0.3 to 3 μm, which is the wavelength of sunlight, is a Mie scattering region for particles having a particle size of several μm. When Mie scattering is calculated, the particle size is about 1 μm. Reflectivity is highest. For this reason, it is general that the particle size of the reflective particles of sunlight is around 1 μm. For the calculation of Mie scattering, the formula of Light Scattering Theory (Department of Mechanical and Aerospace Engineering University of Florida; David W. Hahn) was used.

  The present inventor has intensively studied to further improve the reflectance, and found that the reflectance can be greatly improved by setting the particle diameter and refractive index of the particles and the refractive index of the resin within appropriate ranges. It was.

  First, it was found that the reflectivity increases when particles having a d-line refractive index of 2.5 or more and 3.2 or less and an average particle diameter 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 ° orientations with respect to the incident light. However, the only light that actually reflects the incident light and exits the film is backscattering. Therefore, the larger the particle size, the greater the shielding effect and the less forward scattering. Therefore, in order to actually improve the reflectance, the particle size needs to be 2 μm or more. On the other hand, if the average particle size exceeds 5 μm, the unevenness of the film increases 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 resin matrix is 1.32 or more with respect to the d-line refractive index of the particles of 2.5 or more and 3.2 or less. It has been found that the reflectance is highest at 1.42 or less. As shown in FIG. 3, when the refractive index of the resin 11 is high, the refractive index difference 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 refractive index difference with the hollow particles 10 becomes too wide, and the light that has entered the hollow particles 10 repeats reflection 12 within the particles. As a result, it is presumed that the light is confined without being able to go out to the resin 11 side, and conversely, the reflectance is lowered. Therefore, with respect to the d-line refractive index of the particles of 2.5 or more and 3.2 or less, the reflectance can be improved by the resin matrix of 1.32 or more and 1.42 or less, and the temperature reduction effect can be enhanced.

[Thermal barrier paint for optical equipment]
Below, the material structure of the thermal insulation coating material of this invention and the manufacturing method of the thermal insulation coating material of this invention are demonstrated.

《Material composition》
The thermal barrier coating material for optical equipment according to the present invention comprises pore-containing particles having an average particle diameter of 100 nm or less and a high refractive index having a d-line refractive index of 2.5 or more and 3.2 or less in a solution obtained by dissolving a resin in a solvent. Containing particles.

(Particles having a d-line refractive index of 2.5 to 3.2 (high refractive index particles))
First, the high refractive index particles having a d-line refractive index of 2.5 to 3.2 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 material. In addition, when it is necessary to adjust the color, inorganic pigments such as chromium oxide, titanium, copper oxide, tungsten, platinum, iron oxide, and hematite that absorb in the visible light region, and azo organic pigments can be used. . However, compared with titanium oxide having a low extinction coefficient in the visible to infrared range, a material having a particularly high extinction coefficient in the visible light range tends to have a slightly lower solar reflectance. By adjusting the particle diameter within the range, higher solar reflectance can be obtained. High refractive index particles may be used alone or in combination.

  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. On the other hand, if the average particle size exceeds 5 μm, the unevenness of the film increases and the film thickness accuracy deteriorates.

  Moreover, the surface of the high refractive index particle | grains in this invention may be coat | covered with arbitrary organic materials and inorganic materials. The shape may be indefinite, spherical, flake shaped, or hollow, but more preferably has a shape with less surface irregularities.

  The total content of 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 thermal barrier coating. 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. On the other hand, if the particle content exceeds 90% by weight, the brittleness of the coating film is deteriorated.

(Vacuum-containing particles having an average particle size of 100 nm or less)
Next, the 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 formed by including pore-containing particles having an average particle diameter 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, or an organic resin can be used. Preferably, hollow silica can be used.
As long as the shape of the pore-containing particles having an average particle size of 100 nm or less in the present invention is hollow, a porous structure may be included.
The pore-containing particles having an average particle diameter of 100 nm or less in the present invention may be spherical, irregular, or elliptical.

  As the hollow particles, either through rear (JGC) or SiLINAX (Nippon Mining) can be used.

  The average particle diameter 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. On the other hand, when the average particle size exceeds 100 nm, scattering occurs at the interface between the resin and the hollow particles, and the reflectance is lowered.

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

  In the present invention, the porosity of the pore-containing particles having an average particle size of 100 nm or less is preferably 10% by volume or more and 90% by volume or less. When the porosity is less than 10% by volume, it is difficult to lower 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.

  In the present invention, the content of pore-containing particles having an average particle diameter of 100 nm or less is preferably 5% by volume or more and 50% by volume or less with respect to all components of the thermal barrier paint excluding the solvent. When the content is less than 5% by volume, it is difficult to reduce the refractive index of the coating film. Moreover, when content exceeds 50 volume%, the abrasion resistance of a coating film will deteriorate.

(resin)
Next, the resin of the present invention will be described.
As resin in this invention, it is resin selected from an acrylic resin, a urethane resin, an epoxy resin, and these combination, Preferably a urethane acrylate resin is preferable.

  As acrylic resins, Almatex 784 (Mitsui Chemicals), Almatex 785-5 (Mitsui Chemicals), Almatex 748-5M (Mitsui Chemicals), Metallock (Cemedine), Boncourt 40-418-EF (DIC), Boncourt Any of CE-6400 (DIC) can be used.

  As the urethane resin, any of ADEKA polyether BPX-21 (ADECA), ADEKA polyether EDP-300 (ADEKA), and ADEKA NEW ACE V14-90 (ADECA) can be used. As the urethane resin curing agent, any of Takenate D110N (Mitsui Chemicals), D160N (Mitsui Chemicals), D120N (Mitsui Chemicals), and D140N (Mitsui Chemicals) can be used. 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 of jER828 (Mitsubishi Chemical), jER1001 (Mitsubishi Chemical), 834X90 (Mitsubishi Chemical), EP-4100 (Adeka), EP-5100-75X (Adeka) can be used. Moreover, as an epoxy resin hardening | curing agent, any of ADEKA HARDNER H30 (ADEKA), ADEKA HARDNER 6019 (ADEKA), and ADEKA HARDNER EH-551CH (ADEKA) can be used. About an epoxy resin and a hardening | curing agent, it can mix and use so that an equivalence ratio may be set to 1: 1.

  As urethane acrylate resins, Olester Q164 (Mitsui Chemicals), Olester Q691 (Mitsui Chemicals), Olester Q723 (Mitsui Chemicals), Olester Q628 (Mitsui Chemicals), AH-600 (Kyoeisha Chemical), 8965 (Eupika) Either of these can be used. Further, as a 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.

  Moreover, it is preferable that the pencil hardness of resin is H or more and 5H or less, More preferably, it is 1H or more and 3H or less. When the pencil hardness is less than H, the wear resistance deteriorates. Moreover, when pencil hardness exceeds 5H, it will become weak to a thermal shock. The content of the resin of the present invention is preferably 5% by weight or more and 50% by weight or less, more preferably 7% by weight or more and 35% by weight or less with respect to the thermal barrier coating. When the content of the resin in the present invention is less than 5% by weight, the adhesion with the substrate is deteriorated. On the other hand, when the resin content 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 as a mixture of a plurality of types.

  The preferred viscosity of the thermal barrier coating is 10 mPa · s or more and 10000 mPa · s or less. When the viscosity of the thermal barrier coating is less than 10 mPa · s, there may be a portion where the thickness of the thermal barrier film after application becomes thin. Moreover, when it becomes larger than 10000 mPa · s, the coating property of the heat-shielding paint is lowered.

(Additive)
The thermal barrier coating material of the present invention may contain other optional additives. Examples thereof include dispersants, curing agents, curing catalysts, plasticizers, thixotropic agents, leveling agents, infrared transmissive organic colorants, infrared transmissive inorganic colorants, preservatives, ultraviolet absorbers, antioxidants, Examples include coupling agents, 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 (BIC Chemie Japan), DISPERBYK-110 (BIC Chemie Japan), DISPERBYK-111 (BIC Chemie Japan), DISPERBYK-102 (BIC Chemie Japan), DISPERBYK-190 (BIC Chemie Japan), DISPERBYK -106 (Bicchemy Japan), DISPERBYK-180 (Bicchemy Japan), DISPERBYK-108 (Bicchemy Japan), or Demall EP (Kao) can be used.

<< Production Method of Thermal Barrier Paint >>
The method for producing the thermal barrier paint of the present invention will be described below.
As a method for producing the thermal barrier paint of the present invention, the high refractive index particles having a d-line refractive index of 2.5 to 3.2 and the pore-containing particles having an average particle diameter of 100 nm or less can be dispersed in the paint. Any method can be used. As an example, a bead mill, a ball mill, a jet mill, a three-roller, a planetary rotating device, a mixer, an ultrasonic disperser, and the like can be given.

[Thermal barrier film for optical equipment]
The material structure and film structure of the thermal barrier film of the present invention will be described below.
《Material composition》
The material structure of the thermal barrier film for optical equipment of the present invention will be described below.
The thermal barrier film of the present invention includes a high refractive index particle having a d-line refractive index of 2.5 or more, 3.2 or less, pore-containing particles having an average particle size of 100 nm or less, and a resin.

(High refractive index particles having a d-line refractive index of 2.5 to 3.2)
In the thermal barrier film formed by applying the thermal barrier coating, the content of the high refractive index particles having a d-line refractive index of 2.5 to 3.2 in the present invention is 20 volumes with respect to the thermal barrier film. It is preferable that it is a ratio of% or more and 60 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 the reflectance due to sunlight decreases. Moreover, when content of high refractive index particle | grains exceeds 60 volume%, the brittleness of a coating film will deteriorate.

(Vacuum-containing particles having an average particle size of 100 nm or less)
In the present invention, the content of the pore-containing particles having an average particle diameter of 100 nm or less 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. Moreover, when content exceeds 50 volume%, the abrasion resistance of a coating film will deteriorate.

(resin)
The content of the resin with respect to the heat shielding 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. When the content of the resin in the present invention is less than 10% by volume, the adhesion with the substrate is deteriorated. Moreover, when the resin content in the present invention exceeds 78% by volume, the reflectance of sunlight deteriorates.

(Additive)
The thermal barrier paint of the present invention may contain other optional additives as a part of the resin matrix as long as the d-line refractive index of the resin matrix falls within the range of 1.32 to 1.42. Examples thereof include dispersants, curing agents, curing catalysts, plasticizers, thixotropic agents, leveling agents, infrared transmissive organic colorants, infrared transmissive inorganic colorants, preservatives, ultraviolet absorbers, antioxidants, Examples include coupling agents, 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 structure>
The thermal barrier film 9 of the present invention is formed at least outside the substrate 5. As the form, you may closely_contact | adhere with the base material 5 and the primer layer which improves adhesiveness between the base material 5 and the thermal-insulation film | membrane 9 may be provided.

(Base material)
Any material can be used as the substrate, but metals and plastics are preferred. Examples of the metal material include aluminum, titanium, stainless steel, and a magnesium alloy. As an example of the plastic material, polycarbonate resin, acrylic resin, ABS resin, fluorine resin, and the like can be given.

  The thickness of the substrate 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. When the film thickness is less than 0.5 mm, it is difficult to maintain the shape of the lens barrel. Moreover, when 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 an epoxy resin, a urethane resin, an acrylic resin, a silicone resin, and a fluorine resin. Further, the primer layer includes particles of the present invention or particles other than the present invention, colorant, dispersant, curing agent, curing catalyst, plasticizer, thixotropic agent, leveling agent, organic colorant, inorganic colorant, preservative. , UV absorbers, antioxidants, coupling agents, and 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 be lowered, and if it exceeds 30 μm, the film thickness accuracy may be adversely affected.

(Thickness of the thermal barrier 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 substrate side, and the reflectance of sunlight deteriorates. When 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 Thermal Barrier Film of the Present Invention >>
Any coating method and effect method can be used as long as the thermal barrier coating of the present invention can be applied uniformly so that the thermal barrier coating of the present invention has an average film thickness of preferably 10 μm or more and 70 μm or less.

  As an example of the coating method of the thermal barrier film for the optical apparatus of the present invention, brush coating, spray coating, dip coating, transfer and the like can be mentioned. Further, the heat shielding film may be a single layer coating or a multilayer coating, and may be subjected to a textured process in order to exhibit design properties.

  In addition, as a method for curing a thermal barrier film for an optical device of the present invention, it may be left at room temperature, may be accelerated by arbitrary heat, or may be given ultraviolet rays. Examples of the method of curing by applying heat include a heating furnace, a heater, and infrared heating. The curing temperature is preferably room temperature to 400 ° C, more preferably room temperature to 200 ° C.

[Example]
Hereinafter, preferred embodiments of the present invention will be described.
In Examples 1 to 13, the preparation of the thermal barrier coating, the production of the thermal barrier film, the evaluation of the reflectance, the evaluation of the temperature, the pencil hardness, and the evaluation of the film thickness accuracy were performed as follows.

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

  Next, a method for 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 blank of an alumina sintered body in which 100% reflection occurs on a test piece mounting portion 14 of a test piece whose incident angle is inclined by 5 ° with respect to the incident light 1 was measured, and a baseline measurement was performed. Then, the test piece which formed the light shielding film of this invention instead of the blank in the test piece attachment part 14 was installed, the light of 400 nm-2600 nm was made to inject, and it detected with the detector 15, and measured the reflectance. Moreover, the reflectance described the value of the average reflectance every 1 nm in 400 nm-2600 nm. The reflectivity has a correlation with the temperature evaluation result, and a favorable value was shown in the following temperature evaluation result at 90% or more. From this, it can be said that if the reflectance is 90% or more, it is a good heat-shielding film.

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

The test piece 17 for temperature evaluation was used by forming the thermal barrier film of the present invention on a metal plate of 100 mm square and 1 mm thickness. Any of stainless steel, aluminum, titanium, magnesium alloy and the like was used for the metal plate. Further, the heat-shielding film of the present invention was applied to the surface of the metal plate with a spin coater so as to have a desired film thickness, and baked. The temperature measuring jig 19 was a white cardboard having a surface of 120 mm × 120 mm × 120 mm, and a 90 mm × 90 mm square window portion was provided in the temperature evaluation test piece 17 mounting portion.
As the lamp 16, Hilux MT150FD6500K (Iwasaki Electric) was used.

  Next, a test piece 17 for temperature evaluation was attached to the temperature measurement jig 19, and a thermocouple was attached to the back surface of the test piece 17 for temperature evaluation. A temperature measuring jig 19 to which a test piece 17 for temperature evaluation 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 and 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, 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 are mixed with a planetary rotator for temperature evaluation. This was applied to the surface of the test piece 17 and fired.

  If the temperature reduction effect was 10 ° C. or higher, it was evaluated as a good (in the following table: good) thermal barrier film. Moreover, when a temperature reduction effect will be less than 10 degreeC, it is not a favorable thermal barrier film (the following table | surface: defect).

<Evaluation method of film thickness accuracy>
Below, the evaluation method of film thickness precision is demonstrated. Optical devices have strict positional accuracy, but if the film thickness accuracy varies, the positional accuracy deteriorates. The heat shielding film of the present invention was applied to a metal plate having a thickness of 30 mm square and a thickness of 1 mm on the metal film accuracy evaluation sample by spraying so that the heat shielding film of the present invention had a desired film thickness and baked. Twenty samples for evaluation were prepared, and the film thickness was measured at five locations with a micrometer per sheet, and the average value was calculated to obtain the film thickness. Moreover, the average value of the film thickness of 20 test pieces was calculated, and the maximum deviation from the average value was used as the value of the film thickness variation. The maximum amount of deviation is the maximum amount of deviation for 100 test pieces in total of 20 test pieces × 5 places.

  If the film thickness variation was within ± 10 μm, it was evaluated as a good (the following table: good) thermal barrier film. If the film thickness variation exceeds ± 10 μm, the positional accuracy deteriorates, so that it becomes difficult to use as an optical instrument (the following table: defective).

<Evaluation method of pencil hardness>
Below, the evaluation method of pencil hardness is demonstrated. For the sample for evaluating the film thickness accuracy, the thermal barrier film of the present invention was applied to a metal plate having a 30 mm square and a thickness of 1 mm with a spray so as to have a desired film thickness, followed by firing. If the pencil hardness is H or more, it can be said to be a good thermal barrier film. Therefore, Mitsubishi Pencil High Uni H was used as the test pencil, and centered vertically with # 400 sandpaper. The pressing angle of the pencil was 45 °, and a distance of 10 mm was moved by applying a pressure of 10N. The number of tests is 5 times, and the heat-shielding film without any scratches is (the following table: good (pencil hardness H or higher)), and the film where scratches or peeling is seen (the following table: defective (less than pencil hardness H)) is did.

Example 1
<Preparation of thermal barrier paint>
In Example 1, a thermal barrier paint was produced by the following method. 210 g of titanium oxide (HT0210 (Toho Titanium; average particle size 2 μm)), 35 g of acrylic resin (Almatex 784 (Mitsui Chemicals)), 100 g of hollow silica (through shear (JGC): 50% porosity), 2.4 g of dispersant (DISPERBYK-180 (Bicchemy Japan)) and 30 g of solvent (butyl acetate) were weighed and stirred for 10 minutes with a planetary rotating device (Awatori Nitaro; Sinky) to obtain the thermal barrier paint of Example 1. .

<Preparation of thermal barrier film>
In Example 1, a thermal barrier film was produced by the following method under the materials and conditions described in Table 1. The above thermal barrier paint is 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 as to have a film thickness of 40 μm, and cured at 130 ° C. for 1 hour, The thermal barrier film of Example 1 was obtained.

(Examples 2 to 13)
In Examples 2 to 13, thermal barrier films were produced in the same manner as in Example 1 except that the materials and conditions shown in Tables 1 to 3 were used.
About titanium oxide, hollow silica, and urethane acrylate, the same thing was used in all the Examples and the 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 in a rotary kiln, followed by firing and pulverization at a temperature of 1100 ° C. for 2 hours. JR-1000 (Taika) was used as a particle having an average particle diameter of 1 μm.

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

  As a measurement result, the reflectance of the thermal barrier film is preferably 90% or more. Moreover, it is preferable that the temperature reduction effect has 10 degreeC or more of difference with a blank. The pencil hardness is preferably H or higher. The film thickness accuracy is preferably within ± 10 μm.

  In Example 1, titanium oxide having an average particle diameter of 2 μm, acrylic resin, and hollow silica were used, and the refractive index of the resin matrix composed of acrylic resin and hollow silica was adjusted to 1.41. Table 4 shows the results of evaluating the reflectance and 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 10 degrees C or more and was favorable. Also, 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 polyether BPX-21 (ADEKA)) was used as compared with Example 1. Table 4 shows the results of evaluating the reflectance and 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 10 degrees C or more and was favorable. Also, 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)) was used as compared with Example 1. Table 4 shows the results of evaluating the reflectance and 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 10 degrees C or more and was favorable. Also, 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)) was used as compared to Example 1. Table 4 shows the results of evaluating the reflectance and temperature reduction effect, pencil hardness, and film thickness accuracy of the obtained heat shield film. The evaluation result of reflectance was 98%, which was good. Moreover, the temperature reduction effect was 10 degrees C or more and was favorable. Also, 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, compared with Example 1, urethane acrylate (Olestar Q691 (Mitsubishi Chemical)) was used, and a thermal barrier 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 and 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 10 degrees C or more and was favorable. Also, 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, compared with Example 1, urethane acrylate (Olestar Q691 (Mitsubishi Chemical)) was used, and a thermal barrier 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 and temperature reduction effect, pencil hardness, and film thickness accuracy of the obtained thermal barrier film. The evaluation result of the reflectance was 94%, which was good. Moreover, the temperature reduction effect was 10 degrees C or more and was favorable. Also, 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 is 200 μm or more and a temperature shock is applied, film cracking may occur.

  In Example 7, compared with Example 1, urethane acrylate (Olestar Q691 (Mitsubishi Chemical)) was used, and a thermal barrier 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 and temperature reduction effect, pencil hardness, and film thickness accuracy of the obtained thermal barrier film. The evaluation result of the reflectance was 91%, which was good although slightly inferior. Moreover, the temperature reduction effect was 10 degrees C or more and was favorable. Also, 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, with respect to Example 1, titanium oxide having an average particle diameter of 5 μm was used, urethane acrylate (Olestar Q691 (Mitsubishi Chemical)) was used, and the d-line refractive index of the resin matrix was adjusted to 1.39. . Table 5 shows the results of evaluating the reflectance and temperature reduction effect, pencil hardness, and film thickness accuracy of the obtained thermal barrier film. The evaluation result of the reflectance was 95%, which was good. Moreover, the temperature reduction effect was 10 degrees C or more and was favorable. Also, the pencil hardness was H or higher, which was good. In addition, although some unevenness occurred on the surface, the evaluation result of the film thickness accuracy was within ± 10 μm, which was good.

  In Example 9, compared with Example 1, titanium oxide having an average particle diameter of 1 μm and titanium oxide having an average particle diameter of 2 μm are used in combination, and urethane acrylate (Olestar Q691 (Mitsubishi Chemical)) is used. The linear refractive index was adjusted to 1.39. Table 5 shows the results of evaluating the reflectance and temperature reduction effect, pencil hardness, and film thickness accuracy of the obtained thermal barrier film. The evaluation result of the reflectance was 95%, which was good. Moreover, the temperature reduction effect was 10 degrees C or more and was favorable. Also, 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 diameter of 2 μm was adjusted to 22% by volume with respect to Example 1, and urethane acrylate (Olestar Q691 (Mitsubishi Chemical)) was used. The rate was adjusted to 1.39. Table 5 shows the results of evaluating the reflectance and temperature reduction effect, pencil hardness, and film thickness accuracy of the obtained thermal barrier film. The evaluation result of the reflectance was 95%, which was good. Moreover, the temperature reduction effect was 10 degrees C or more and was favorable. Also, 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 diameter of 2 μm was adjusted to 59% by volume with respect to Example 1, and urethane acrylate (Olestar Q691 (Mitsubishi Chemical)) was used. The rate was adjusted to 1.39. Table 6 shows the results of evaluating the reflectance and temperature reduction effect, pencil hardness, and film thickness accuracy of the obtained thermal barrier film. The evaluation result of reflectance was 98%, which was good. Moreover, the temperature reduction effect was 10 degrees C or more and was favorable. Also, 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 diameter of 2 μm was adjusted to 20% by volume with respect to Example 1, and urethane acrylate (Olestar Q691 (Mitsubishi Chemical)) was used. The rate was adjusted to 1.39. Table 6 shows the results of evaluating the reflectance and temperature reduction effect, pencil hardness, and film thickness accuracy of the obtained thermal barrier film. The evaluation result of the reflectance was 94%, which was good. Moreover, the temperature reduction effect was 10 degrees C or more and was favorable. Also, 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 diameter of 2 μm was adjusted to 60% by volume with respect to Example 1, and urethane acrylate (Olestar Q691 (Mitsubishi Chemical)) was used. The rate was adjusted to 1.39. Table 6 shows the results of evaluating the reflectance and temperature reduction effect, pencil hardness, and film thickness accuracy of the obtained thermal barrier film. The evaluation result of reflectance was 98%, which was good. Moreover, the temperature reduction effect was 10 degrees C or more and was favorable. Also, the pencil hardness was H or higher, which was good. Moreover, the evaluation result of film thickness accuracy was ± 10 μm or less, which was good. However, when the film thickness was 200 μm or more and a temperature shock was applied, the film was sometimes cracked because of the large amount of titanium oxide inorganic pigment.

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

Fluoro-based resins include Poly (2,2,3,3-tetrafluoropropyl methacrylate) (Aldrich), Poly (2,2,3,3-tetrafluoropropyl acrylate) (Aldrich), Poly (2,2,2-trifluoroethyl methacrylate) ) (Aldrich) or Zaffle (Daikin) can be used.
As the zinc oxide, zinc oxide particles #F (Sakai Chemical) having an average particle diameter of 3.8 μm were used.
As silicon particles, silicon SIE23PB (high purity chemistry) having an average particle diameter of 5 μm was used.
Titanium oxide having an average particle diameter of 7 μm was prepared by drying titanium oxide having a particle diameter of 80 nm at a low temperature in a rotary kiln, followed by firing and pulverization at a temperature of 1100 ° C. for 2 hours.
Crosslinked styrene acrylic hollow particles (primary particle size 300 nm; Adachi Shin Sangyo) were used as hollow particles having an average particle size of 100 nm or more.

Tables 7 and 8 show the materials and addition amounts of the thermal barrier films of Comparative Examples 1 to 7.
Tables 9 and 10 show the results of evaluation using the thermal barrier films of Comparative Examples 1 to 7, respectively.
In Comparative Example 1, a fluororesin (Zeffle (Daikin)) having a coating film hardness lower than that of Example 1 was used. Table 9 shows the results of evaluating the reflectance and 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 10 degrees C or more and was favorable. 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, as compared with Example 1, titanium oxide having a small average particle diameter of 1 μm was used. Table 9 shows the results of evaluating the reflectance and 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 90%. Moreover, the temperature reduction effect was less than 10 degreeC and the effect was low. The pencil hardness was H or higher and 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 and 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 90%. Moreover, the temperature reduction effect was less than 10 degreeC and the effect was low. The pencil hardness was H or higher and 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 of d-line refractive index of 4 as compared with Example 1 was used. Table 9 shows the results of evaluating the reflectance and 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 90%. Moreover, the temperature reduction effect was less than 10 degreeC and the effect was low. The pencil hardness was H or higher and was good. Moreover, the evaluation result of the film thickness accuracy was within ± 10 μm, which was good.

  In Comparative Example 5, as compared with Example 1, titanium oxide having an average particle diameter of 7 μm and a large particle diameter was used. Table 9 shows the results of evaluating the reflectance and 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 10 degreeC or more, and was favorable. The pencil hardness was H or higher and was good. However, the evaluation result of the film thickness accuracy exceeded ± 10 μm and was bad.

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

  In Comparative Example 7, as compared with Example 1, solid particles were used as particles having an average particle size of 100 nm or less. Table 10 shows the results of evaluating the reflectance and 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 90%. Moreover, the temperature reduction effect was less than 10 degreeC and the effect was low. The pencil hardness was H or higher and 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 used outdoors and precision equipment.

1. Incident light 2. reflected light; Transmitted light4. Infrared reflective film
5. Base material 6. Lens 7. Fitting part 8. Lens barrel 9. Thermal barrier film 10. Particle 11 Resin 12. Reflection within particles 13. Integrating sphere 14. Test piece attachment part 15. Detector 16. Lamp 17. Test piece for temperature evaluation 18. Temperature measurement point 19. Temperature measurement jig

Claims (19)

An optical apparatus having a lens and a lens barrel provided with the lens inside a lens barrel,
A thermal barrier film on at least a part of the outer peripheral surface of the lens barrel;
The thermal barrier film is a thermal barrier film in which high refractive index particles having a d-line refractive index of 2.5 to 3.2 are dispersed in a resin matrix, and the resin matrix includes a urethane resin, an acrylic resin, an epoxy resin. An optical material comprising pore-containing particles having an average particle diameter of 100 nm or less in a resin selected from a resin and a combination thereof, wherein the average particle diameter of the high refractive index particles is 2 μm or more and 5 μm or less machine.   2. The optical apparatus according to claim 1, wherein the high refractive index particles are contained in a ratio of 20 volume% or more and 60 volume% or less with respect to the thermal barrier film.   The optical apparatus according to claim 1, wherein the high refractive index particles are made of titanium oxide.   The optical device according to any one of claims 1 to 3, wherein the pore-containing particles are hollow particles.   The optical apparatus according to claim 4, wherein an average particle diameter of the pore-containing particles is 5 nm or more and 100 nm or less.   The optical device according to claim 4 or 5, wherein the pore-containing particles are hollow silica.   The optical device according to any one of claims 1 to 6, wherein the pore-containing particles are included in a proportion of 5% by volume or more and 50% by volume or less with respect to the heat shielding film.   The optical instrument according to claim 1, wherein the resin constituting the resin matrix has a pencil hardness of H to 5H.   The optical apparatus according to claim 1, wherein the heat shield film has an average film thickness of 10 μm or more and 70 μm or less.   A thermal barrier film in which high refractive index particles having a d-line refractive index of 2.5 or more and 3.2 or less are dispersed in a resin matrix, the resin matrix comprising a urethane resin, an acrylic resin, an epoxy resin, and combinations thereof A heat shielding film, wherein the selected resin comprises pore-containing particles having an average particle diameter of 100 nm or less, and the average particle diameter of the high refractive index particles is 2 μm or more and 5 μm or less.   The thermal barrier film according to claim 10, wherein the high refractive index particles are contained in a proportion of 20% by volume or more and 60% by volume or less with respect to the thermal barrier film.   The thermal barrier film according to claim 10 or 11, wherein the high refractive index particles are made of titanium oxide.   The thermal barrier film according to any one of claims 10 to 12, wherein the pore-containing particles are hollow particles.   The thermal barrier film according to claim 13, wherein the average particle diameter of the pore-containing particles is 5 nm or more and 100 nm or less.   The thermal barrier film according to claim 13 or 14, wherein the pore-containing particles are hollow silica.   The thermal barrier film according to any one of claims 10 to 15, wherein the pore-containing particles are contained in a proportion of 5% by volume to 50% by volume with respect to the thermal barrier film.   The thermal insulation film according to any one of claims 10 to 16, wherein the resin constituting the resin matrix has a pencil hardness of H or more and 5H or less.   The thermal barrier 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.   2. A hole-containing particle having an average particle diameter of 100 nm or less and a d-line refractive index of 2.5 or more in a solution in which a resin selected from a urethane resin, an acrylic resin, an epoxy resin, and a combination thereof is dissolved in a solvent. A thermal barrier coating comprising 2 or less and a high refractive index particle having an average particle diameter of 2 to 5 μm.

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