KR102249755B1 - Composition for Radiative Cooling Film and Radiative Cooling film Prepared from Same - Google Patents

Abstract

The present invention relates to a composition for manufacturing a radiation cooling film and a radiation cooling film manufactured using the same, wherein the composition for a radiation cooling film according to the present invention has an infrared absorption rate by only a simple process of molding and curing a polymer resin using a conventional technique. It is possible to manufacture a radiation cooling film that is excellent and has a low visible light defect yield. In addition, by varying the type of inorganic particles, a light-transmitting radiation cooling film having a high visible light transmittance or a light-reflecting radiation cooling film having a high visible light reflectance can be prepared, so that it can be appropriately applied in various industrial applications.

Description

Composition for radiation cooling film and radiation cooling film prepared using the composition {Composition for Radiative Cooling Film and Radiative Cooling film Prepared from Same}

The present invention relates to a composition for manufacturing a radiation cooling film and a radiation cooling film manufactured using the composition, and more particularly, a radiation cooling film capable of effectively absorbing radiant heat and significantly lowering the room temperature, is prepared by a simple method. It relates to a composition that can be used and a radiation cooling film.

In general, the wavelength of sunlight can be classified into gamma rays, X-rays, ultraviolet rays, visible rays, infrared rays, microwaves, and radio waves. Among them, the wavelength we feel as visual sunlight is in the visible region, and the wavelength we feel as solar heat in our daily life is It is an infrared region that has a longer wavelength than the visible ray region.

In general, glass reflects only a part of the infrared ray. For this reason, in summer, radiant heat generated from outdoor solar heat enters the room to increase the indoor temperature, and in winter, infrared rays generated from indoor heating devices escape to the outside and reduce the indoor temperature. Energy is wasted by lowering the efficiency of the air conditioner and lowering it.

Therefore, for energy efficiency, a system having an excellent heat shielding effect to prevent the outside solar heat from flowing into the interior in summer, and an excellent insulation effect to prevent the indoor heating heat from escaping to the outside in winter would be desirable.

In this regard, conventionally, in order to impart a better heat dissipation effect to the glass, a heat-reflecting glass is used, but the visible light transmittance is 40%, and there is a problem in that it requires more heating by blocking visible light entering the room in winter.

In addition, low-E glass using a sputtering coating method has been released and sold in order to improve the insulating effect of the glass, but in order to prevent the coating from being oxidized, the coating part must be configured to be embedded in the multilayer glass plate. The structure must be filled with an inert gas, so the manufacturing method is difficult, and edge stripping treatment equipment is required when manufacturing a multilayer glass, so manufacturing and handling are difficult and manufacturing cost is high.

As an alternative, a study has been proposed to block radiant heat by making a radiation cooling film and attaching it to glass. For example, Korean Laid-Open Patent Publication No. 10-2013-0077940 describes a polymer film in which radiation shielding performance is maximized by dispersing a metal powder having radiation shielding performance in a polymer. However, since the film of this document needs to be manufactured into a multilayer tungsten sheet by thermocompressing tungsten particles, there is a problem that the manufacturing process is complicated and expensive.

In addition, Korean Patent Laid-Open Publication No. 10-2018-0080840 describes a thermal barrier film that has excellent durability, does not have a problem of damage due to a difference in thermal expansion rate with a glass substrate, and can effectively block infrared rays. There was a disadvantage that the transmittance of the region remained at the level of 50%.

As described above, since a radiation cooling film according to the prior art requires reflection in a high visible light region, it has a mostly opaque structure, and thus it is technically difficult to provide a radiation cooling film for a solar cell.

As a result of recognizing and researching the above problems, the inventors of the present invention found that it is possible to provide a radiation cooling film applicable to solar cells as well as general radiation cooling by controlling the transmission or reflection of visible light by adjusting the composition of the film. The invention was completed.

It is an object of the present invention to provide a composition for a radiation cooling film capable of producing a radiation cooling film capable of controlling reflectance and transmittance while having excellent absorption in the infrared region and low absorption in the visible region. will be.

Another object of the present invention is to provide a radiation cooling film prepared by using the composition.

Another object of the present invention is to provide a method of manufacturing a radiation cooling film.

In order to achieve the above object, the present invention provides a composition for a radiation cooling film comprising a polymer resin, a lubricant, and a mixture of inorganic particles as a composition for producing a radiation cooling film.

In the present invention, the inorganic particles may include airgel or inorganic nanoparticles.

In the present invention, the polymer resin is polydimethylsiloxane (PDMS), silicone (silicone), perfluoropolyether (PFPE), polyurethane (polyurethane, PU), polylactic acid; PLA), ABS (Acrylonitrile Butadiene Styrene), high density polyethylene (HDPE), polycarbonate (PC), polystyrene (PS), polyester, polyolefin, polyamide ), Poly Vinyl Alcohol, N-vinylpyrrolidone, N-vinyl caprolactam, dimethylacrylamide, hydroxyethylacrylamide, 2-acryloyloxyethyl isocyanate, isobornyl acrylate, tetrahydro Furfuryl acrylate, phenoxy polyethylene glycol acrylate, lauryl acrylate, benzyl acrylate, ethoxyethyl acrylate, phenoxyethyl acrylate, cyclic trimethylolformal acrylate, 6-hexanediol diacrylate, trimethyl All propane triacrylate, pentaerythritol tetraacrylate, tripropylene glycol diacrylate, tetraethylene glycol diacrylate, 1,1 (bisacryloyloxymethyl) ethyl isocyanate, polyester acrylate and urethane acrylate It may be one or more selected from the group consisting of.

In the present invention, the lubricating oil is olive oil, fluorinated oil, silicone oil, essential oil, paraffin oil, and petroleum oil. It may be one or more selected from the group consisting of.

In the present invention, the airgel may be at least one selected from silica gel, carbon airgel, and graphene airgel.

In the present invention, in the case of a film required for radiant cooling of a solar cell, the airgel may have an average diameter of 1 to 20 μm.

In the present invention, in the case of a film required for general radiation cooling, the nanoparticles may have an average diameter of 300 to 1000 nm. The inorganic nanoparticles may be nanoparticles having high visible light reflectance, such as _{TiO 2} , ZnO, and CeO _2.

The composition for a radiation cooling film of the present invention may include 5 to 40 parts by weight of lubricating oil based on 100 parts by weight of the polymer resin.

The composition for a radiation cooling film of the present invention may further include 10 to 100 parts by weight of inorganic particles based on 100 parts by weight of the lubricating oil.

The composition for a radiation cooling film of the present invention adds at least one solvent selected from the group consisting of dichloromethane (DCM), tetrahydrofuran, dioxane, methyl ethyl ketone (MEK), and dimethylformamide (DMF). Can be included as.

In the present invention, the solvent may be included so that the concentration of the total composition is 0.05 to 0.30g/mL.

The present invention also provides a radiation cooling film formed by curing a composition for a radiation cooling film comprising a polymer resin, a lubricant and a blend of inorganic particles.

In the radiation cooling film of the present invention, the inorganic particles are aerogels and may have a visible light transmittance of 90% or more.

In the radiation cooling film of the present invention, the inorganic particles are TiO ₂ nanoparticles, and may have a visible light reflectance of 80% or more.

The radiation cooling film of the present invention may also have a micro or nano structure formed on its surface.

The present invention also comprises the steps of mixing 10 to 100 parts by weight of inorganic particles based on 100 parts by weight of lubricating oil; Mixing 5 to 40 parts by weight of the mixture based on 100 parts by weight of the polymer resin; And it provides a method for producing a radiation cooling film comprising the step of forming a film by molding the mixture.

The composition for a radiation cooling film according to the present invention is capable of producing a radiation cooling film having excellent infrared absorption rate and low visible light defect yield by simply molding and curing a polymer resin using a conventional technique. In addition, by varying the type of inorganic particles, a light-transmitting radiation cooling film having a high visible light transmittance or a light-reflecting radiation cooling film having a high visible light reflectance can be prepared, so that it can be appropriately applied in various industrial applications.

1 shows a manufacturing process of a light-reflective radiation cooling film (a) containing inorganic nanoparticles and a light-transmitting radiation cooling film (b) containing airgel.
2 shows the state of a mixture of a polymer resin and a lubricating oil according to the presence or absence of an airgel.
3 shows a conceptual diagram of manufacturing a radiation cooling film according to an embodiment of the present invention.
4 shows a conceptual diagram of manufacturing a radiation cooling film according to another embodiment of the present invention.
5 shows a conceptual diagram of manufacturing a radiation cooling film according to still another embodiment of the present invention.
6 is a graph showing light absorption, transmittance, and reflectance according to wavelength in the infrared region of a radiation cooling film according to an exemplary embodiment of the present invention.
7 is a graph showing light absorption at visible and infrared wavelengths of a radiation cooling film including _{SiO 2} or TiO ₂ according to an exemplary embodiment of the present invention.
8 shows light transmittance (a) and light reflectance (b) in the visible light region of a radiation cooling film including _{SiO 2} or TiO ₂ according to an exemplary embodiment of the present invention.
9(a) shows an electron microscope (SEM) image of a radiation cooling film including inorganic nanoparticles to which a nanostructure is applied according to an embodiment of the present invention.
9(b) shows an SEM image of a radiation cooling film including an airgel to which a microstructure is applied according to an embodiment of the present invention.
10A is a graph showing reflectance of a radiation cooling film to which a nanostructure is applied and a planar radiation cooling film having the same composition according to an exemplary embodiment of the present invention according to a wavelength in a visible light region.
10(b) is a graph showing the absorption rate according to the wavelength in the infrared region of the radiation cooling film to which the microstructure is applied and the planar radiation cooling film having the same composition according to an exemplary embodiment of the present invention.

Hereinafter, specific aspects of the present invention will be described in more detail. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by an expert skilled in the art to which the present invention belongs. In general, the nomenclature used in this specification is well known and commonly used in the art.

The present invention relates to a composition for producing a radiation cooling film.

The composition of the present invention comprises a blend of a polymer resin and a lubricating oil.

In the present invention, the term "blend" means a state in which two or more substances that are not dissolved in each other are uniformly dispersed.

In the present invention, a radiation cooling film may be prepared by curing a composition in which a polymer resin and a lubricant are uniformly mixed with each other.

In general, the miscibility of two materials can be calculated as the free energy for mixing as follows.

ΔG _mix = ΔH-TΔS

If the free energy of mixing is greater than zero, the two substances are difficult to mix with each other. This means that a large interfacial tension acts between the two substances, so that the two substances prefer to be separated rather than uniformly mixed.

In the present invention, it was found that the interfacial tension of two materials having a free energy of mixing greater than zero can be canceled by using a porous aerogel as a commercial reagent. The porous airgel has nano-sized pores providing an extremely large surface area (about 310 m ² /g), and also has excellent oil adsorption due to its chemical affinity.

When the airgel is added to the mixture, the free energy of mixing can be determined as follows.

ΔG _mix = ΔG _PS + ΔG _LS + ΔG _PL

(P: polymer, L: lubricant, S: solid particles)

Accordingly, the Gibbs energy is changed to less than 0, and the lubricant and the polymer resin can be stably mixed.

The left glass bottle of FIG. 2 shows a mixture of a polymer resin (PDMS) and a lubricant (olive oil) to which no airgel is added. It is confirmed that the two materials were not uniformly mixed and phase separation appeared. On the other hand, in the glass bottle on the right to which the airgel (silica gel) was added, it can be seen visually that the three substances maintain a homogeneous mixture.

The lubricating oil is olive oil, fluorinated oil, silicone oil, essential oil, paraffin oil, mineral oil, etc. desirable. Particularly preferably, it is good to use petroleum oil or silicone oil.

In the present invention, “lubricating oil” may have the same meaning as “oil” in some cases.

Clove oil may be used as the essential oil, and the paraffinic oil is n-octane, n-decane, n-dodecane, hexadecane , Octadecane, and the like, and the petroleum-based oil may be selected from diesel, gasoline, crude oil, and the like.

Including essential oils, particularly clove oil, among the lubricating oils can impart antibacterial effects to the manufactured products.

In the present invention, the lubricating oil may be included in an amount of 5 to 40 parts by weight based on 100 parts by weight of the polymer resin. In the case of lubricating oil, since it has a bonding group that a polymer resin or aerogel does not have, it can absorb infrared light in a region that cannot be absorbed by the polymer resin and aerogel alone. For example, when PDMS is used as a polymer resin and SiO ₂ aerogel is used, it is difficult to absorb the infrared region absorbed by the CC bond, but by including n-hexadecane, the wavelength in the infrared region due to the CC bond can be absorbed. have.

In the present invention, the composition including a mixture of the polymer resin and the lubricant may further include inorganic particles, and the inorganic particles may have the form of airgels or nanoparticles. The inorganic particles may be included in the composition to adjust the visible light transmittance of the prepared film. For example, a radiation cooling film prepared from a composition containing an airgel can be used as a highly transparent film by transmitting visible light. In addition, a radiation cooling film prepared from a composition containing inorganic nanoparticles can be used as a highly reflective film that reflects visible light.

As the airgel, silica gel, carbon airgel, graphene airgel, or the like may be used. The airgel absorbs the lubricating oil so that the lubricating oil is stably mixed with the polymer resin, and the lubricating oil is not easily evaporated even after it is commercialized. The airgel preferably has an average diameter of 1 to 20 µm, more preferably, an average diameter of 5 to 15 µm.

In the case of the nanoparticles, it is preferable to use inorganic nanoparticles having high reflectance in the visible light region, such as _{titanium dioxide (TiO 2} ), zinc oxide (ZnO), cerium oxide (CeO _{2 ), and the like.}

In one embodiment of the present invention, both the radiation cooling film including silica airgel and the radiation cooling film including titanium dioxide nanoparticles exhibit excellent infrared absorption rate and low absorption rate for visible light, but a film including silica airgel It was confirmed that most of the visible light was transmitted, and the film including inorganic nanoparticles such as titanium dioxide reflected most of the visible light.

The inorganic particles are preferably added in an appropriate amount in consideration of the miscibility of the polymer resin and the lubricating oil and the mechanical properties of the product to be manufactured, and may be used in an amount of 10 to 100 parts by weight, and 20 to 50 parts by weight. More preferable.

In the present invention, the polymer resin is polydimethylsiloxane (PDMS), silicone, perfluoropolyether (PFPE), polyurethane (polyurethane, PU), polyimide (PI) Liquid polymers such as the like may be included. The liquid polymer may be mixed with lubricating oil without a separate solvent, and may be mixed with lubricating oil by airgel if necessary.

For example, silicone elastomer and silicone oil can be used in the composition of the present invention because of their excellent miscibility without the addition of airgel, but silicone elastomer and olive oil are not mixed without the addition of airgel.

The polymer resin of the present invention is also polylactic acid (PLA), ABS (Acrylonitrile Butadiene Styrene), high density polyethylene (HDPE), polycarbonate (PC), thermoplastic polyurethane (TPU) , Polystyrene (PS), polyester, polyolefin, polyamide, polyvinyl alcohol, and a thermoplastic polymer resin selected from a combination thereof.

When a thermoplastic polymer resin is used as the polymer resin, it is preferable to dissolve the solid polymer in a solvent to make it liquid and mix it with a lubricant. As a solvent usable in the present invention, dichloromethane (DCM), tetrahydrofuran (THF), dioxane, methyl ethyl ketone (MEK), dimethyl formamide (DMF), and the like can be used.

In order to select a suitable solvent that can be mixed with the lubricating oil while liquefying the solid polymer, the Flory-Huggins solution can be applied. The Flory-Huggins constant (χ) is defined as follows.

In the above formula, δ ₁ and δ ₂ represent the solubility constants of the solvent and the solute, V ₁ represents the molar volume of the solvent, R represents the gas constant, and T represents the absolute temperature.

The smaller the χ value, the better the solvent and solute can be dissolved.

For example, the χ of polylactic acid (PLA) and dichloromethane (DCM) is 0.03, which is much less than the χ of PLA and toluene of 0.42. Therefore, it can be seen that DCM is more suitable than acetone for dissolving PLA.

In addition, the constant χ of DCM and lubricant is also important for mixing. It can be seen that olive oil (χ=0.47) and petroleum oil (χ=0.91) are more easily mixed with DCM than water (χ=21.43) or ethylene glycol (χ=6.08).

The solvent is preferably added in an amount such that the concentration of the total composition is 0.05 to 0.30 g/mL, more preferably 0.05 to 0.15 g/mL.

Types of suitable solvents according to exemplary solid polymer resins are shown in Table 1 below.

polymer menstruum Polylactic acid (PLA) Dichloromethane (DCM)
Tetrahydrofuran
Dioxane Acrylonitrile Butadiene Styrene (ABS) DCM
Methyl ethyl ketone (MEK) Thermoplastic polyurethane (TPU) Dimethylformamide (DMF) Polystyrene (PS) DCM Acrylic MEK Polycarbonate (PC) DCM
DMF

The method of preparing the composition of the present invention using a solid polymer resin comprises the steps of dissolving a polymer resin in a first solvent to prepare a polymer solution; And mixing the polymer solution and a lubricant.

In the above method, mixing the lubricating oil may include mixing a lubricating oil solution obtained by dissolving the lubricating oil in a second solvent.

In a preferred embodiment of the present invention, in the step of mixing the lubricating oil, it is preferable to further mix inorganic particles, and after adding the inorganic particles to the lubricating oil solution, it is most preferable to mix the polymer resin solution and the lubricating oil solution.

According to the present invention, the polymer is dissolved in a solvent to form a liquid phase at room temperature, and the lubricant is dissolved in a separate solvent, and then the liquid polymer and the lubricant are mixed so that the polymer can be well mixed with the lubricant, and the polymer is easily cured. Or prevent the lubricant from evaporating easily at high temperatures.

The first solvent and the second solvent are preferably the same solvent.

The lubricating oil solution preferably has a concentration of 10 to 50% (v/v), more preferably 15 to 30% (v/v).

In the present invention, the mixing of the two solutions is preferably continuously stirred while adding the polymer solution little by little to the lubricating oil solution.

The composition of the present invention can be prepared as a radiation cooling film by a known method.

For example, it can be manufactured using various known techniques such as coating, molding, 3D printing, and the like.

For example, the composition is diluted 1/10 to 1/50 in a solvent such as nucleic acid (hexane), coated by spin coating, cured at 100 to 150°C for 1 to 2 hours, and then separated to a radiation cooling film Can be manufactured.

The radiation cooling film of the present invention may preferably have a thickness of 10 to 500 μm, more preferably 20 to 400 μm. In particular, when manufacturing a radiation cooling film containing airgel, it is preferable to have a thickness of 50 to 100 μm, and when manufacturing a radiation cooling film containing inorganic nanoparticles, it is preferable to control it to have a thickness of 100 to 300 μm. desirable.

As an exemplary manufacturing method of the radiation cooling film of the present invention, as shown in Fig. 3, a polymer-liquid-polymer sandwiched film by thermal compression bonding by a roller or hot press after placing the composition between transparent polymer films It is also possible to manufacture.

Alternatively, as shown in FIG. 4, it is possible to prepare a radiation cooling film having a hydrophobic pattern by applying the composition of the present invention on a mold having a dimple structure and then curing it.

Alternatively, as shown in FIG. 5, the composition of the present invention is mixed with a volatile solvent and then sprayed onto a substrate such as a glass window to form a self-assembled structure to prepare a radiation cooling film. I can.

In addition, in an exemplary embodiment of the present invention, the radiation cooling film may include a micro or nano structure on the surface. The micro or nano structure is not particularly limited, but it is preferable to have a pattern in which protrusions or concave portions having the shape of a cylinder, a hexagonal column, a tetrahedron, etc. are repeated at regular intervals, or a pattern in which polygonal channels are repeatedly formed. .

The micro or nano structure may be prepared by casting a composition for a radiation cooling film on the mold after producing a mold having a micro or nano structure, but is not particularly limited thereto, and a technique generally used in the present technical field is used. Thus, a film having a micro or nano structure can be prepared.

Preferably, the nanostructure may be applied to the surface of the radiation cooling film for the purpose of increasing the reflectance of the visible light region of the radiation cooling film.

In addition, preferably, the microstructure may be applied to the surface of the radiation cooling film for the purpose of increasing the light absorption rate in the infrared region of the radiation cooling film.

The radiation cooling film manufactured by the method of the present invention has excellent absorption rate of infrared light, and at the same time, it has a characteristic that it can transmit or reflect the visible light region with little absorption. In particular, it is possible to manufacture a radiation cooling film with high permeability or high reflectivity by selecting the type of inorganic particles.

Example

The present invention will be described in more detail through the following examples. However, these examples show some experimental methods and compositions for illustrative purposes of the present invention, and the scope of the present invention is not limited to these examples.

Experimental Example 1: Preparation of radiation cooling film

Mineral oil and porous silica airgel (average particle size 3㎛, REM-tech) were mixed in a weight ratio of 5:1. Transparent PDMS (Dow Corning) was mixed with the mixture in a weight ratio of 7:3 to prepare a composition for a radiation cooling film.

The composition was diluted 20 times with nucleic acid, coated on a Teflon substrate at 2,000 rpm, cured at 130° C. for 1 hour, and separated to prepare a thin film having a thickness of about 50 μm.

The absorption, transmittance, and reflectance according to the wavelength of the prepared radiation cooling film were measured using a Fourier transform infrared spectrometer (FT-IR Spectrometer, Nicolet iS50, Thermo Fisher Scientific Instrument). Each parameter was measured based on the following criteria.

-Reflectance (%): Measuring the ratio of irradiating IR beam to the film and reflecting it

-Transmittance (%): Irradiation of IR beam to the film and measuring the transmittance ratio

-Absorption (%): 100-Reflectance-Transmittance

The measurement results are shown in FIG. 6.

6, the radiation cooling film of the present invention exhibits a very high absorption rate and very low transmittance in the infrared region, and the reflectance is close to 0 in all wavelength regions, so that it is possible to transmit light and absorb infrared rays with excellent efficiency. Confirmed.

Experimental Example 2: Preparation of light-transmitting/light-reflective radiation cooling film

_{Olive oil was mixed with TiO 2} nanoparticles (Junsei chemical) having an average particle size of 300 to 800 nm in a weight ratio of 5:1. Transparent PDMS (Dow Corning) was mixed with the mixture in a weight ratio of 7:3 to prepare a composition for a light reflective radiation cooling film.

The composition was coated on a Teflon substrate at 400 rpm and then separated to prepare a film having a thickness of about 200 μm.

_{In addition, silicone oil was mixed with SiO 2} particles (REM tech) having an average particle diameter of 3 to 20 μm in a weight ratio of 5:1, and a composition for a light-transmitting radiation cooling film was prepared in the same manner as above.

The composition was diluted 20 times with nucleic acid, coated on a Teflon substrate at 2,000 rpm, and separated to prepare a thin film having a thickness of about 50 μm.

Fig. 7 shows the light absorption rates at the visible and infrared wavelengths of the two films.

In FIG. 7, both films hardly absorb light in the visible wavelength region (TiO ₂ : 8.5%; SiO ₂ : 2.5%), but the infrared wavelength region showed excellent absorption.

The light transmittance and light reflectance in the visible light region of the two films are shown in Figs. 8(a) and (b), respectively.

From FIG. 8, _{the film including SiO 2} nanoparticles exhibited a light transmittance of 90% or more at a visible wavelength, and a light reflectance of 7% or less, and _{a film including TiO 2} nanoparticles was 3% or less at a visible wavelength. It showed a light transmittance and a light reflectance of 90% or more.

_{Therefore, when SiO 2} nanoparticles are included as inorganic particles, a radiation cooling film having excellent light transmittance can be prepared, and when TiO ₂ nanoparticles are included as inorganic particles, a radiation cooling film having excellent light reflectance can be prepared. Confirmed.

Experimental Example 3: Preparation of a light-transmitting/light-reflective radiation cooling film to which a nano/micro structure was applied

_{Olive oil was mixed with TiO 2} nanoparticles (Junsei chemical) having an average particle size of 300 to 800 nm in a weight ratio of 5:1. Transparent PDMS (Dow Corning) was mixed with the mixture in a weight ratio of 7:3 to prepare a composition for a light reflective radiation cooling film.

The composition was coated on a mold to which a nano structure was applied at 400 rpm and then separated to prepare a film to which a nano structure having a thickness of about 200 μm was applied.

_{In addition, silicone oil was mixed with SiO 2} particles (REM tech) having an average particle diameter of 3 to 20 μm in a weight ratio of 5:1, and a composition for a light-transmitting radiation cooling film was prepared in the same manner as above.

The composition was coated on a mold to which a micro structure was applied at 100 rpm and then separated to prepare a film to which a micro structure having a thickness of about 100 μm was applied.

Electron microscopy (SEM) pictures of the two films to which the nano/micro structure was applied are shown in FIGS. 9(a) and (b).

It can be seen from FIG. 9(a) that nanostructured pores are densely formed on the surface of the radiation cooling film including inorganic nanoparticles.

In addition, it can be seen from FIG. 9(b) that a hexagonal column-shaped microhole is formed on the surface of the radiation cooling film including the airgel.

FIG. 10(a) shows the reflectance of the visible light region of the radiation cooling film to which the nanostructure is applied compared to the planar radiation cooling film of the same composition, and FIG. 10(b) is the infrared region of the radiation cooling film to which the microstructure is applied. It is a graph showing the absorption rate of compared with the planar radiation cooling film of the same composition.

In FIG. 10(a), it can be seen that in the case of the radiation cooling film including inorganic nanoparticles to which the nanostructure is applied, there is an increase in light reflectance of 3% or less in the visible wavelength compared to the case where the nanostructure is not applied. From this, it can be seen that the nanostructure formed on the film plays a role in increasing the reflectance of the visible wavelength.

In addition, in FIG. 10(b), in the case of the radiation cooling film including the airgel to which the microstructure was applied, the light absorption rate was increased by 60% or less at the infrared wavelength compared to the case where the microstructure was not applied. In particular, it was confirmed that a high light absorption rate was increased in a region of 3 to 8 μm, and thus a light absorption rate of 99% or more may be exhibited in an atmospheric window (8 to 13 μm).

As described above, specific parts of the content of the present invention have been described in detail, and for those of ordinary skill in the art, this specific technology is only a preferred embodiment, and the scope of the present invention is not limited thereto. It will be obvious. Accordingly, it will be said that the substantial scope of the present invention is defined by the appended claims and their equivalents.

Claims (16)

As a composition for producing a radiation cooling film,
A liquid polymer resin or a liquid polymer resin obtained by dissolving a solid polymer resin in a solvent at room temperature, a lubricating oil, and a mixture of inorganic particles,
It contains 5 to 40 parts by weight of lubricating oil based on 100 parts by weight of the polymer resin,
The inorganic particles are airgel (aerogel) having an average diameter of 1 to 20㎛, the composition for a radiation cooling film. delete The method of claim 1,
The polymer resin is polydimethylsiloxane (PDMS), silicone, perfluoropolyether (PFPE), polyurethane (polyurethane, PU), thermoplastic polyurethane (TPU), polyether. Polyimide (PI), polylactic acid (PLA), ABS (Acrylonitrile Butadiene Styrene), high density polyethylene (HDPE), polycarbonate (PC), polystyrene (PS), polyester (Polyester), polyolefin (polyolefin), polyamide (Polyamide), polyvinyl alcohol (Poly Vinyl Alcohol), and a composition for a radiation cooling film, characterized in that at least one selected from the group consisting of polyester acrylate. The method of claim 1,
The lubricating oil is at least one selected from olive oil, fluorinated oil, silicone oil, essential oil, paraffin oil, and mineral oil. Characterized in that, the radiation cooling film composition. The method of claim 1,
The composition for a radiation cooling film, characterized in that the airgel is at least one selected from silica gel, carbon airgel and graphene airgel. delete delete delete The method of claim 1,
A composition for a radiation cooling film comprising 10 to 100 parts by weight of inorganic particles based on 100 parts by weight of the lubricating oil. The method of claim 1,
The solvent is one or more selected from the group consisting of dichloromethane (DCM), tetrahydrofuran, dioxane, methyl ethyl ketone (MEK) and dimethyl formamide (DMF), for radiation cooling film Composition. The method of claim 10,
The composition for a radiation cooling film, characterized in that the solvent is contained so that the concentration of the total composition is 0.05 to 0.30g / mL. A liquid polymer resin or a mixture of a lubricating oil and inorganic particles in which a liquid polymer resin or a solid polymer resin is dissolved in a solvent at room temperature, but contains 5 to 40 parts by weight of lubricating oil based on 100 parts by weight of the polymer resin, , The inorganic particles are airgel (aerogel) having an average diameter of 1 to 20㎛, formed by curing the composition for a radiation cooling film, a radiation cooling film. delete delete The method of claim 12,
Radiation cooling film, characterized in that the micro or nano structure is formed on the surface. Mixing 10 to 100 parts by weight of inorganic particles based on 100 parts by weight of lubricating oil;
Mixing the mixture at room temperature in a ratio of 5 to 40 parts by weight of the lubricating oil based on 100 parts by weight of a liquid polymer resin in which a liquid polymer resin or a solid polymer resin is dissolved in a solvent; And
Forming a film by molding the mixture;
Including,
The method of manufacturing a radiation cooling film, wherein the inorganic particles are airgels having an average diameter of 1 to 20 μm.

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