JP2022077682A - Radiation cooling type air conditioning clothing - Google Patents

Abstract

To provide a radiation cooling type air conditioning clothing capable of lowering a sensible temperature even when used in an environment that is a solar radiation environment with direct sunlight.SOLUTION: Provided in a clothing body E is an air blowing part 1 that makes cooling air flow between the clothing body E and a wearer. A radiation cooling layer CP is attached to an outer face of the clothing boy E. The radiation cooling layer CP is configured to include an infrared radiation layer A that radiates infrared light IR from a radiation face H, and a light reflection layer B positioned on an opposite side of an existing side of the radiation face H in the infrared radiation layer A. The infrared radiation layer A is a resin material layer J adjusted to a thickness that radiates a heat radiation energy larger than an absorbed solar energy at a bandwidth from a wavelength of 8 μm to a wavelength of 14 μm, and the light reflection layer B contains silver or a silver alloy.SELECTED DRAWING: Figure 1

Description

The present invention relates to a radiatively cooled air-conditioned clothes having a radiative cooling action.

As a conventional example of air-conditioned clothes, the clothes body is provided with a blower for flowing cooling air between the clothes body and the wearer so that the outer surface of the clothes body is exposed to the outside (for example). , Patent Document 1 and Patent Document 2).

Incidentally, in Patent Document 1, the blower unit is configured to send the sucked air into the space between the clothes body and the wearer, and the air flowing in the space between the clothes body and the wearer is configured. It is configured to be discharged through the gap between the collar of the garment body and the wearer's neck and the gap between the cuffs of the garment body and the wearer's wrist.

Further, in Patent Document 2, the blower portion is configured to suck and discharge the air in the space between the clothes body and the wearer to the outside, and the space between the clothes body and the wearer is negative pressure. The outside air flows into the air flow passage through the gap between the collar of the garment body and the wearer's neck and the gap between the cuffs of the garment body and the wearer's wrist. Has been done.
Incidentally, in the case of this form of air-conditioned clothes, a member forming a space through which air flows between the clothes body and the wearer is often provided on the inner surface side of the clothes body.

Although detailed description of the material constituting the clothing body is omitted in Patent Documents 1 and 2, in general, cotton or water-repellent polyester is used as the material constituting the clothing body. There are many.

Japanese Patent No. 6158675 Japanese Patent No. 4399765

Conventional air-conditioned clothes are easy to get a cool feeling when the environment is shaded, but it is difficult to get a cool feeling when the environment is a daytime sunlight environment with direct sunlight. It felt hot.

That is, when the material constituting the clothes body is a light-shielding type such as water-repellent polyester, when the clothes body is irradiated with sunlight, the sunlight is absorbed by the clothes body and the clothes body is from the wearer. As a result, the inside of the clothes became hot, which made me feel hot.

Further, when the material constituting the clothes body is a non-light-shielding type such as cotton, it is possible to prevent the clothes body from becoming hotter than the wearer due to the absorption of sunlight by the clothes body. The sunlight that passed through the body of the clothes radiated the wearer, which made me feel hot.

In other words, when the environment in which the conventional air-conditioned clothes are used is a daytime solar radiation environment with direct sunlight, the surface temperature of the wearer may rise above the body temperature, and the sensible temperature may rise, so improvement is desired. It was something that was done.

The present invention has been made in view of such circumstances, and an object thereof is to provide a radiatively cooled air-conditioned clothes capable of lowering the sensible temperature even when the environment in which it is used is a sunshine environment with direct sunlight. At the point.

The radiatively cooled air-conditioned clothes of the present invention are provided with a blower portion in the clothes body for flowing cooling air through an air flow passage between the clothes body and the wearer.
A radiative cooling layer is attached to the outer surface of the clothing body,
The radiation cooling layer is configured to include an infrared radiation layer that emits infrared light from a radiation surface and a light reflection layer located on the opposite side of the infrared radiation layer from the side where the radiation surface exists. ,
The infrared radiant layer is a resin material layer adjusted to a thickness that emits thermal radiation energy larger than the absorbed solar energy in a band having a wavelength of 8 μm to 14 μm.
The light reflecting layer is characterized in that it is provided with silver or a silver alloy.

That is, radiative cooling refers to a phenomenon in which a substance emits electromagnetic waves such as infrared rays to the surroundings to lower its temperature. By utilizing this phenomenon, for example, it is possible to construct a radiative cooling layer that cools the object to be cooled without consuming energy such as electricity.

That is, in the radiation cooling layer, the infrared radiation layer radiates a large amount of thermal radiation energy in the band of wavelength 8 μm to 14 μm, and the light reflection layer transmits the light (ultraviolet light, visible light, infrared light) transmitted through the infrared radiation layer. Light) is reflected and radiated from the radiation surface, and the light (ultraviolet light, visible light, infrared light) transmitted through the infrared radiation layer is projected onto the cooling target (clothing body) to be cooled (clothing body). By avoiding the heating of the energy, the object to be cooled (the body of the clothes) can be cooled even in the daytime radiant environment.

In addition to the light transmitted through the infrared radiation layer, the light reflection layer also has the effect of reflecting the light emitted from the infrared radiation layer to the existing side of the light reflection layer toward the infrared radiation layer. However, in the following description, it is assumed that the light reflecting layer is provided for the purpose of reflecting the light (ultraviolet light, visible light, infrared light) transmitted through the infrared radiating layer.

To add an explanation, sunlight incident from the radiation surface of the resin material layer as the infrared radiation layer in the radiation cooling layer passes through the resin material layer and then on the opposite side of the radiation surface of the resin material layer. It is reflected by a certain light-reflecting layer and escapes from the radiation surface to the outside of the system.
In the description of the present specification, when simply referred to as light, the concept of the light includes ultraviolet light (ultraviolet light), visible light, and infrared light. In terms of the wavelength of light as an electromagnetic wave, these include electromagnetic waves having a wavelength of 10 nm to 20000 nm (0.01 μm to 20 μm).

Further, the heat transfer (heat input) to the radiative cooling layer is converted into infrared rays by the resin material layer and is released from the radiant surface to the outside of the system.
In this way, the radiant cooling layer reflects the sunlight radiating to the radiant cooling layer, and heat transfer to the radiant cooling layer (for example, heat transfer from the atmosphere or from the body of the clothes cooled by the radiant cooling layer). Heat transfer) can be radiated to the outside of the system as infrared light.

Further, since the resin material layer is adjusted to have a thickness that emits heat radiation energy larger than the absorbed solar energy in the band of wavelength 8 μm to wavelength 14 μm, sunlight is emitted by a light reflecting layer provided with silver or a silver alloy. It can exert a cooling function even in a daytime solar environment while appropriately reflecting it.

Therefore, even in the daytime solar radiation environment, the radiative cooling layer attached to the outer surface of the clothes body can cool the clothes body, and as a result, the temperature rise of the clothes body can be suppressed even in the daytime solar radiation environment.
Of course, the presence of the radiative cooling layer suppresses the irradiation of the clothes body with sunlight, so that the sunlight does not pass through the clothes body and irradiate the wearer.
Therefore, even in the daytime solar radiation environment, the clothes body can be cooled by the radiative cooling action to lower the sensible temperature.

That is, in addition to promoting evaporation of the wearer by flowing cooling air between the clothes body and the wearer to cool the wearer, the clothes body is cooled by the radiant cooling layer. By lowering the temperature of the cooling air flowing between the main body and the wearer, the sensible temperature of the wearer can be appropriately lowered.

By the way, since the resin material layer is formed of a highly flexible resin material, the resin material layer can be made flexible, and the light reflecting layer is formed as, for example, a thin film of silver. It is possible to provide flexibility by such means.
Therefore, the radiative cooling layer including the resin material layer and the light reflection layer can be made flexible, and the radiative cooling layer can be satisfactorily attached while being along the outer surface of the clothing body.

In short, according to the characteristic configuration of the radiatively cooled air-conditioned clothes of the present invention, the sensible temperature can be lowered even when the environment in which the clothes are used is a sunlight environment with direct sunlight.

A further characteristic configuration of the radiatively cooled air-conditioned clothing of the present invention is configured to include a protective layer between the infrared radiant layer and the light reflecting layer.
The protective layer is a polyolefin resin having a thickness of 300 nm or more and 40 μm or less, or a polyethylene terephthalate resin having a thickness of 17 μm or more and 40 μm or less.

That is, sunlight incident from the radiating surface of the resin material layer as the infrared radiating layer passes through the resin material layer and the protective layer, and then is a light reflecting layer on the opposite side of the radiating surface of the resin material layer. It is reflected by and escaped from the radiation surface to the outside of the system.

Further, since the protective layer is formed of a polyolefin resin having a thickness of 300 nm or more and 40 μm or less, or an ethylene terephthalate resin having a thickness of 17 μm or more and 40 μm or less. Since it is possible to suppress discoloration of the silver or silver alloy of the light-reflecting layer even in the daytime sunlight environment, the cooling function can be provided even in the daytime sunlight environment while appropriately reflecting sunlight in the light-reflecting layer. It can be demonstrated accurately.

That is, in the absence of the protective layer, the radicals generated in the resin material layer reach the silver or silver alloy forming the light reflecting layer, and the moisture transmitted through the resin material layer forms the light reflecting layer. By reaching the silver or the silver alloy, the silver or the silver alloy of the light reflecting layer may be discolored in a short period of time, and the light reflecting function may not be properly exerted. It is possible to prevent the silver or silver alloy of the layer from discoloring in a short period of time.

The explanation will be added about suppressing the discoloration of silver or the silver alloy of the light reflecting layer by the protective layer.
When the protective layer is made of a polyolefin resin and has a thickness of 300 nm or more and is formed in a form of 40 μm or less, the polyolefin resin has ultraviolet rays in the entire wavelength range of ultraviolet rays having a wavelength of 0.3 μm to 0.4 μm. Since it is a synthetic resin having a light absorption rate of 10% or less, the protective layer is less likely to be deteriorated by absorption of ultraviolet rays.

Since the thickness of the polyolefin-based resin forming the protective layer is 300 nm or more, the radicals generated in the resin material layer are blocked from reaching the silver or silver alloy forming the light-reflecting layer, and also. It exerts a good blocking function such as blocking the moisture transmitted through the resin material layer from reaching the silver or silver alloy forming the light reflecting layer, and discoloration of the silver or silver alloy forming the light reflecting layer. Will be able to be suppressed.

That is, the protective layer formed of the polyolefin resin deteriorates while forming radicals on the surface side away from the reflective layer due to the absorption of ultraviolet rays, but since the thickness is 300 nm or more, the formed radicals. Does not reach the light-reflecting layer, and even if it deteriorates while forming radicals, the progress of deterioration is slow due to the low absorption of ultraviolet rays, so that the above-mentioned blocking function can be used for a long period of time. Will be demonstrated.

When the protective layer is formed of an ethylene terephthalate resin having a thickness of 17 μm or more and a form of 40 μm or less, the ethylene terephthalate resin has a wavelength of 0.3 μm to 0.4 μm as compared with the polyolefin resin. Although it is a resin material having a high light absorption rate of ultraviolet rays in the wavelength range of ultraviolet rays, since the thickness is 17 μm or more, the radicals generated in the resin material layer reach the silver or silver alloy forming the light reflecting layer. In addition, the protective layer exhibits a blocking function for a long period of time, such as blocking the moisture transmitted through the resin material layer from reaching the silver or silver alloy forming the light reflecting layer. It is possible to suppress discoloration of silver or a silver alloy forming the above.

That is, the protective layer formed of the ethylene terephthalate resin deteriorates while forming radicals on the surface side away from the reflective layer due to the absorption of ultraviolet rays, but is formed because the thickness is 17 μm or more. The radicals do not reach the reflective layer, and even if they deteriorate while forming radicals, the thickness is 17 μm or more, so that the above-mentioned blocking function is exhibited for a long period of time.

When the protective layer is formed of the polyolefin resin and the ethylene terephthalate resin, the reason for setting the upper limit of the thickness is to prevent the protective layer from exhibiting heat insulating properties that do not contribute to radiative cooling as much as possible. .. In other words, the thicker the protective layer, the more heat insulating properties that do not contribute to radiative cooling. Therefore, the upper limit of the thickness will be set.

In short, according to a further characteristic configuration of the radiatively cooled air-conditioned clothes of the present invention, the clothes body can be satisfactorily cooled while suppressing discoloration of the silver or silver alloy of the light reflecting layer in a short period of time.

A further characteristic configuration of the radiative cooling type air-conditioned clothes of the present invention is that the radiative cooling layer is attached to the outer surface of the clothes body by a connecting layer of an adhesive or an adhesive.

That is, it can be accurately attached to the outer surface of the flexible clothing body in a state where the radiative cooling layer is brought into close contact with the connecting layer of the adhesive or the adhesive.
By the way, the outer surface of the clothes body is generally formed in a state where irregularities are present instead of a mirror surface, but the radiative cooling layer is connected to the outer surface of the clothes body by a connecting layer of an adhesive or an adhesive. Therefore, it is possible to suppress the reflection of the unevenness of the outer surface of the clothes body on the light reflecting layer and maintain the light reflecting layer in a flat state.

That is, when the unevenness of the outer surface of the clothes body is reflected on the light reflecting layer, the light scattering caused by the unevenness of the outer surface of the clothes body lowers the reflectance of the light reflecting layer, and the light is absorbed. However, by keeping the light-reflecting layer in a flat state, it is possible to suppress a decrease in the reflectance of the light-reflecting layer.

In short, according to the further characteristic configuration of the radiative cooling type air-conditioned clothes of the present invention, the radiative cooling layer can be accurately attached to the outer surface of the flexible clothes body.

A further characteristic configuration of the radiatively cooled air-conditioned clothes of the present invention is that the radiant surface in the radiative cooling layer is formed in an uneven shape.

That is, the surface area of the radiating surface can be increased by forming the radiating surface in an uneven shape, and as a result, the radiative cooling layer can be cooled by wind to improve the cooling function.

For example, when a fan is installed in a work place where a wearer works, the cooling function can be improved by ventilating the air blown by the fan to the radiating surface.

In short, according to the further characteristic configuration of the radiative cooling type air-conditioned clothes of the present invention, the cooling function can be improved.

A further characteristic configuration of the radiatively cooled air-conditioned clothes of the present invention is that the light reflecting layer has a reflectance of 90% or more at a wavelength of 0.4 μm to 0.5 μm and a reflectance of 96% or more for long waves from a wavelength of 0.5 μm. It is in the point that it is.

That is, the sunlight spectrum exists from a wavelength of 0.3 μm to 4 μm, and the intensity increases as the wavelength increases from 0.4 μm, and the intensity increases particularly from the wavelength of 0.5 μm to the wavelength of 2.5 μm.
When the light reflecting layer has a reflectance of 90% or more from a wavelength of 0.4 μm to 0.5 μm and a reflection characteristic of a long wave having a reflectance of 96% or more from a wavelength of 0.5 μm, the light reflecting layer is subjected to sunlight. It absorbs less than about 5% of energy.

As a result, the solar energy absorbed by the light-reflecting layer can be reduced to about 50 W / m ² or less in the middle of the south in the summer, and the radiative cooling by the resin material layer can be satisfactorily performed.
In this specification, the spectrum of sunlight shall be the standard of AM1.5G unless otherwise specified.

In short, according to the further characteristic configuration of the radiatively cooled air-conditioned clothes of the present invention, it is possible to suppress the absorption of solar energy by the light reflecting layer and satisfactorily perform radiative cooling by the resin material layer.

A further characteristic configuration of the radiatively cooled air-conditioned clothes of the present invention is that the film thickness of the resin material layer is
The wavelength average of the light absorption rate from 0.4 μm to 0.5 μm is 13% or less, and the wavelength average of the light absorption rate from 0.5 μm to 0.8 μm wavelength is 4% or less, from 0.8 μm wavelength. It has a light absorption characteristic that the wavelength average of the light absorption rate up to a wavelength of 1.5 μm is within 1% and the wavelength average of the light absorption rate from 1.5 μm to 2.5 μm is 40% or less.
The point is that the thickness is adjusted to a state having a thermal radiation characteristic in which the wavelength average of the emissivity of 8 μm to 14 μm is 40% or more.

The wavelength average of the light absorption rate of the wavelength of 0.4 μm to 0.5 μm means the average value of the light absorption rate for each wavelength in the range of 0.4 μm to 0.5 μm, and the wavelength is 0.5 μm. The same applies to the wavelength average of the light absorption rate from 0.8 μm to the wavelength average of the light absorption rate from 0.8 μm to 1.5 μm, and the wavelength average of the light absorption rate from 1.5 μm to 2.5 μm. Is. Further, other similar descriptions including the emissivity also mean the same average value, and the same applies hereinafter in the present specification.

That is, the light absorption rate and the emissivity (light emissivity) of the resin material layer change depending on the thickness. Therefore, it is necessary to adjust the thickness of the resin material layer so as not to absorb sunlight as much as possible and to emit large heat radiation in the wavelength band of the so-called atmospheric window region (the region of light wavelength of 8 μm to 20 μm).

Specifically, from the viewpoint of the light absorption rate (light absorption characteristic) of sunlight in the resin material layer, the wavelength average of the light absorption rate with a wavelength of 0.4 μm to 0.5 μm is 13% or less, and the wavelength is 0.5 μm. The wavelength average of the light absorption rate of 0.8 μm is 4% or less, the wavelength average of the light absorption rate from 0.8 μm to 1.5 μm is within 1%, and the wavelength average is 1.5 μm to 2.5 μm. It is necessary that the wavelength average of the light absorptivity up to is 40% or less. Regarding the light absorption rate from 2.5 μm to 4 μm, the wavelength average may be 100% or less.
When such a light absorption rate is distributed, the light absorption rate of sunlight is 10% or less, and the energy is 100 W or less.

That is, the light absorption rate of sunlight increases as the film thickness of the resin material layer increases. When the resin material layer is made thick, the radiance of the window of the atmosphere becomes almost 1, and the thermal radiation emitted into the universe at that time becomes 125 W / m ² to 160 W / m ² .
As described above, the sunlight absorption in the light reflecting layer is preferably 50 W / m ² or less.
Therefore, if the sum of the sunlight absorption in the resin material layer and the light reflecting layer is 150 W / m ² or less and the atmospheric condition is good, cooling proceeds. As the resin material layer, it is preferable to use a resin material layer having a small absorption rate near the peak value of the sunlight spectrum as described above.

Further, from the viewpoint of the radiation rate (heat radiation characteristic) that emits infrared light of the resin material layer, the wavelength average of the radiation rate having a wavelength of 8 μm to 14 μm needs to be 40% or more.
That is, in order to emit the heat radiation of about 50 W / m ² of sunlight absorbed by the light reflecting layer from the resin material layer to the universe, it is necessary for the resin material layer to emit more heat radiation.
For example, when the outside air temperature is 30 ° C., the maximum thermal radiation of an atmospheric window having a wavelength of 8 μm to 14 μm is 200 W / m ² (calculated assuming an emissivity of 1). This value is obtained in fine weather, such as in high mountains, where the air is thin and dry. In lowlands, the thickness of the atmosphere is thicker than that of high mountains, so the wavelength band of atmospheric windows becomes narrower and the transmittance decreases. By the way, this is called "the window of the atmosphere becomes narrower".

In addition, the environment in which the radiatively cooled air-conditioned clothes are actually used may be humid, and even in that case, the atmospheric window becomes narrow. The thermal radiation generated in the window area of the atmosphere when used in lowlands is estimated to be 160 W / m ² at 30 ° C. in good condition (calculated as emissivity 1).
Also, as is often the case in Japan, when there is haze in the sky or when smog is present, the atmospheric window becomes even narrower and the radiation to space is about 125 W / m ² .

In view of this situation, the wavelength average of the emissivity of 8 μm to 14 μm must be 40% or more (heat radiation intensity in the window zone of the atmosphere is 50 W / m ² or more) before it can be used in the lowlands of the mid-latitude band.
Therefore, by adjusting the thickness of the resin material layer so as to be within the above-mentioned optically specified range, the heat output from the atmospheric window becomes larger than the heat input due to the absorption of sunlight, and the daytime radiant radiation. Even in the environment, it will be possible to radiate and cool outdoors.

In short, according to the further characteristic configuration of the radiative cooling type air conditioner of the present invention, the heat output from the window of the atmosphere is larger than the heat input due to the light absorption of sunlight, and the radiative cooling can be performed even in a solar radiation environment.

A further characteristic configuration of the radiant cooling type air conditioner of the present invention is that the resin material forming the resin material layer has a carbon-fluorine bond, a siloxane bond, a carbon-chlorine bond, a carbon-oxygen bond, an ether bond, and an ester bond. The point is that it is selected from resins having at least one of the benzene rings.

That is, as the resin material forming the resin material layer, carbon-fluorine bond (CF), siloxane bond (Si—O—Si), carbon-chlorine bond (C—Cl), carbon-oxygen bond (CO). ), An ether bond (R—COO-R), an ester bond (COC), or a colorless resin material having at least one of a benzene ring can be used.

According to Kirchhoff's law, the emissivity (ε) and the light absorption rate (A) are equal. The light absorption rate (A) can be obtained from the absorption coefficient (α) by the following equation 1.
A = 1-exp (−αt) ... (Equation 1) In addition, t is a film thickness.
That is, when the thickness of the resin material layer is increased, a large amount of heat radiation can be obtained in a wavelength band having a large absorption coefficient. In the case of radiative cooling outdoors, it is preferable to use a material having a large absorption coefficient in the wavelength band of 8 μm to 14 μm, which is the wavelength band of the window of the atmosphere. Further, in order to suppress the absorption of sunlight, it is preferable to use a material having no absorption coefficient or a small material in the wavelength range of 0.3 μm to 4 μm, particularly 0.4 μm to 2.5 μm. As can be seen from the relational expression between the absorption coefficient and the light absorption rate of the above formula 1, the light absorption rate (emissivity) changes depending on the film thickness of the resin material layer.

In order to lower the temperature from the surrounding atmosphere by radiant cooling in a solar radiation environment, the resin material forming the resin material layer has a large absorption coefficient in the atmospheric window wavelength band and the absorption coefficient in the sunlight wavelength band. If you choose a material that has almost no light, by adjusting the thickness of the resin material layer, it will hardly absorb sunlight, but it will emit more heat radiation from the window of the atmosphere, that is, the output by radiant cooling rather than the input of sunlight. It is possible to create a larger state.

The absorption spectrum of the resin material forming the resin material layer will be described.
Regarding the carbon-fluorine bond (CF), the absorption coefficient due to CHF and CF ₂ spreads widely over a wide band from the wavelength of 8 μm to 14 μm, which is the window of the atmosphere, and the absorption coefficient is particularly large at 8.6 μm. At the same time, regarding the wavelength band of sunlight, there is no conspicuous absorption coefficient at wavelengths of 0.3 μm to 2.5 μm, which have large energies.

As a resin material having a CF bond,
Polytetrafluoroethylene (PTFE), a completely fluorinated resin,
Polychlorotrifluoroethylene (PCTFE) and polyvinylidene fluoride (PVDF) and polyvinyl fluoride (PVF), which are partially fluorinated resins,
Perfluoroalkoxy alkane resin (PFA), which is a fluororesin copolymer,
Ethylene tetrafluoride / propylene hexafluoride copolymer (FEP),
Ethylene / ethylene tetrafluoride copolymer (ETFE),
Ethylene / chlorotrifluoroethylene copolymer (ECTFE) can be mentioned.

The binding energies of the CC bond, CH bond, and CF bond of the basic structure portion represented by polyvinylidene fluoride (PVDF) are 4.50 eV, 4.46 eV, and 5.05 eV. They correspond to a wavelength of 0.275 μm, a wavelength of 0.278 μm, and a wavelength of 0.246 μm, respectively, and absorb light on the shorter wavelength side than these wavelengths.
Since the solar spectrum has only long waves having a wavelength of 0.300 μm, when a fluororesin is used, it hardly absorbs ultraviolet rays, visible rays, and near infrared rays of sunlight.
In addition, ultraviolet rays have a wavelength on the shorter wavelength side than 0.400 μm, visible rays have a wavelength of 0.400 μm to 0.800 μm, near infrared rays have a wavelength of 0.800 μm to 3 μm, and mid-infrared rays have a wavelength of 3 μm. The range is from 8 μm to 8 μm, and far infrared rays are in the range on the longer wavelength side than the wavelength of 8 μm.

Examples of the resin material having a siloxane bond (Si—O—Si) include silicone rubber and silicone resin. In this resin, a large absorption coefficient due to expansion and contraction of the C—Si bond appears broadly around a wavelength of 13.3 μm, and an absorption coefficient due to the out-of-plane variation angle (pitch) of CSiH ₂ has a wavelength of 10 μm. It appears broad in the center, and the absorption coefficient due to the in-plane variation angle (scissors) of CSiH ₂ appears small near a wavelength of 8 μm. Thus, it has a large absorption coefficient in atmospheric windows. In the ultraviolet region, the binding energy of Si—O—Si in the main chain is 4.60 eV, which corresponds to a wavelength of 0.269 μm and absorbs light on the shorter wavelength side than this wavelength. Since the solar spectrum has only long waves having a wavelength of 0.300 μm, when a siloxane bond is used, it hardly absorbs ultraviolet rays, visible rays, and near infrared rays of sunlight.

Regarding the carbon-chlorine bond (C—Cl), the absorption coefficient due to the C—Cl expansion and contraction vibration appears in a wide band with a half width of 1 μm or more centered on a wavelength of 12 μm.
Further, as a resin material having a carbon-chlorine bond (C—Cl), polyvinyl chloride (PVC) can be mentioned, but in the case of polyvinyl chloride, the C of the alkene contained in the main chain is affected by the electron attraction of chlorine. The absorption coefficient derived from the eccentric vibration of -H appears around the wavelength of 10 μm. That is, it is possible to emit a large amount of heat radiation in the wavelength band of the window of the atmosphere. The bond energy between carbon and chlorine of alkene is 3.28 eV, its wavelength corresponds to 0.378 μm, and it absorbs light on the shorter wavelength side than this wavelength. That is, it absorbs the ultraviolet rays of sunlight, but has almost no absorption in the visible region.

The ether bond (R-COO-R) and the ester bond (COC) have an absorption coefficient from a wavelength of 7.8 μm to 9.9 μm. Further, with respect to the carbon-oxygen bond contained in the ester bond and the ether bond, a strong absorption coefficient appears in the wavelength band of 8 μm to 10 μm.
When the benzene ring is introduced into the side chain of the hydrocarbon resin, absorption becomes widespread from 8.1 μm to 18 μm due to the vibration of the benzene ring itself and the vibration of surrounding elements due to the influence of the benzene ring.
Resins having these bonds include polymethylmethacrylate resin, ethylene terephthalate resin, polytrimethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, and polybutylene naphthalate. For example, the bond energy of the CC bond of methyl methacrylate is 3.93 eV, which corresponds to a wavelength of 0.315 μm and absorbs sunlight having a wavelength shorter than this wavelength, but has almost no absorption in the visible region.

If the resin material forming the resin material layer has the above-mentioned radiation rate and absorption rate characteristics, the resin material layer may be a single layer film of one type of resin material or a multilayer film of a plurality of types of resin material. A single-layer film of a resin material in which a plurality of types are blended or a multilayer film of a resin material in which a plurality of types are blended may be used. The blend also includes copolymers such as alternate copolymers, random copolymers, block copolymers, and graft copolymers, and modified products in which side chains are replaced.

In short, according to a further characteristic configuration of the radiatively cooled air-conditioned clothes of the present invention, the radiative cooling layer can create a state in which the output by radiative cooling is larger than the input of sunlight.

A further characteristic configuration of the radiatively cooled air-conditioned clothes of the present invention is that the main component of the resin material forming the resin material layer is siloxane.
The point is that the thickness of the resin material layer is 1 μm or more.

That is, as can be seen from A = 1-exp (−αt) in the above formula 1, the light absorption rate (emissivity) changes depending on the thickness t. The light absorption rate (emissivity) of the resin material needs to be thick enough to have a large absorption coefficient in the window of the atmosphere.
In the case of a resin material whose main component is a siloxane bond (Si—O—Si), if the film thickness is 1 μm or more, the radiant intensity in the atmospheric window becomes large, and the output by radiant cooling is higher than the input of sunlight. It is possible to create a larger state.

In short, according to a further characteristic configuration of the radiatively cooled air-conditioned clothes of the present invention, when the main component of the resin material forming the resin material layer is siloxane, the radiative cooling layer is radiatively cooled rather than the input of sunlight. The output can create a larger state.

A further characteristic configuration of the radiatively cooled air-conditioned clothes of the present invention is that the thickness of the resin material layer is 10 μm or more.

That is, carbon-fluorine bond (CF), carbon-chlorine bond (C-Cl), carbon-oxygen bond (CO), ester bond (R-COO-R), ether bond (COC). ), In the case of a resin material whose main component is one of the benzene rings, if the film thickness is 10 μm or more, the radiation intensity in the window of the atmosphere becomes large, and the output by radiant cooling is higher than the input of sunlight. You can create a big state.

In short, according to a further characteristic configuration of the radiation-cooled air-conditioning clothing of the present invention, the resin material forming the resin material layer is carbon-fluorine bond (CF), carbon-chlorine bond (C-Cl), carbon. -In the case of a resin material whose main component is oxygen bond (CO), ester bond (R-COO-R), ether bond (COC), or benzene ring, the radiation cooling layer is the sun. The output of radiant cooling can create a larger state than the input of light.

A further characteristic configuration of the radiatively cooled air-conditioned clothes of the present invention is that the thickness of the resin material layer is 20 mm or less.

That is, the thermal radiation of the atmospheric window of the resin material forming the resin material layer is generated within a range of about 100 μm from the material surface.
That is, even if the thickness of the resin material is increased, the thickness that contributes to radiative cooling does not change, and the remaining thickness has the effect of insulating the cold heat after radiative cooling. If a resin material layer that ideally does not absorb sunlight at all is formed, sunlight is absorbed only by the light reflecting layer of the radiatively cooled air-conditioned clothes.

The thermal conductivity of the resin material is generally about 0.2 W / m · K, and when calculated in consideration of this thermal conductivity, when the thickness of the resin material layer exceeds 20 mm, the cooling surface (resin material layer in the light reflecting layer) The temperature of the surface opposite to the side where the plastic exists) rises. Even if there is an ideal resin material that does not absorb sunlight at all, the thermal conductivity of the resin material is generally about 0.2 W / m · K, so if the thickness is 20 mm or more, the heat radiation of the resin material layer Due to (radiant cooling), the main body of the clothes to be cooled on the cooling surface cannot be cooled, and the main body of the clothes is heated by the sunlight, so that the film thickness cannot be 20 mm or more.

In short, according to the further characteristic configuration of the radiatively cooled air-conditioned clothes of the present invention, the clothes body can be appropriately cooled.

A further characteristic configuration of the radiantly cooled air-conditioned clothes of the present invention is that the resin material forming the resin material layer is fluororesin or silicone rubber.

That is, fluororesins whose main component is a carbon-fluorine bond (CF), that is, polytetrafluoroethylene (PTFE), polychlorotrifluoroethylene (PCTFE), polyvinylidene fluoride (PVDF), polyvinyl fluoride (PVF). ), Perfluoroalkoxy fluororesin (PFA), and ethylene tetrafluoride / propylene hexafluoride copolymer (FEPP) have almost no light absorption in the ultraviolet region, visible light, and near-infrared region of the solar spectrum.

Further, a resin having a siloxane bond (Si—O—Si) as a main chain and a small molecular weight in the side chain, that is, silicone rubber, has an ultraviolet light region, a visible light, and a near infrared region in the sunlight spectrum, like a fluororesin. Has almost no light absorption.
The thermal conductivity of the fluororesin and the silicone rubber is 0.2 W / m · K, and in view of this point, these resins exhibit a radiative cooling function even if the thickness is as thick as 20 mm.

In short, according to a further characteristic configuration of the radiant cooling type air-conditioned clothes of the present invention, when the resin material of the resin material layer is fluororesin or silicone rubber, the radiant cooling layer can appropriately exert the radiant cooling function. can.

A further characteristic configuration of the radiant cooling type air conditioner of the present invention is that the resin material forming the resin material layer has one of carbon-chlorine bond, carbon-oxygen bond, ester bond, ether bond, and benzene ring. A resin having the above-mentioned hydrocarbon as a main chain, or a silicone resin having two or more carbon atoms in a side chain hydrocarbon.
The point is that the thickness of the resin material layer is 500 μm or less.

That is, the resin material forming the resin material layer is a carbon-chlorine bond (CF), a carbon-oxygen bond (CO), an ester bond (R-COO-R), and an ether bond (COC). ), When the resin has a hydrocarbon as the main chain having one or more of the benzene rings, or when the side chain hydrocarbon is a silicone resin having two or more carbon atoms. In addition to the absorption of ultraviolet rays by covalently bonded electrons, absorption based on vibration such as bending angle and expansion and contraction of the bond appears in the near infrared region.

Specifically, the absorption by the reference sound of the transition of CH ₃ , CH ₂ , and CH to the first excited state is from 1.6 μm to 1.7 μm in wavelength, 1.65 μm to 1.75 μm in wavelength, and 1.7 μm in wavelength, respectively. appear. Further, absorption of the combined sound of CH ₃ , CH ₂ , and CH by the reference sound appears at a wavelength of 1.35 μm, a wavelength of 1.38 μm, and a wavelength of 1.43 μm, respectively. Further, the overtones of the transition of CH ₂ and CH to the second excited state appear around the wavelength of 1.24 μm, respectively. The reference sound of the angle change and expansion / contraction of the CH bond is distributed over a wide band from a wavelength of 2 μm to 2.5 μm. Further, when it has a structural formula such as R ₁ -CO ₂ -R ₂ , there is a large light absorption around a wavelength of 1.9 μm.

For example, polymethylmethacrylate resin, ethylene terephthalate resin, polytrimethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, and polyvinyl chloride are caused by CH ₃ , CH ₂ , and CH in the near infrared region. It shows similar light absorption characteristics. When these resin materials are thickened to a thickness of 20 mm specified from the viewpoint of thermal conductivity, they are heated by absorbing near infrared rays contained in sunlight. Therefore, when using these resin materials, it is necessary to make the thickness 500 μm or less.

In short, according to a further characteristic configuration of the radiated cooling air conditioner of the present invention, the resin material has one or more of a carbon-chlorine bond, a carbon-oxygen bond, an ester bond, an ether bond, and a benzene ring. Absorption of near infrared rays can be suppressed when a resin having a hydrocarbon as a main chain or a silicone resin having two or more carbon atoms in a side chain hydrocarbon.

A further characteristic configuration of the radiant cooling type air conditioner of the present invention is that the resin material forming the resin material layer is a blend of a resin containing a carbon-fluorine bond and a siloxane bond and a resin having a hydrocarbon as a main chain. The point is that the thickness of the resin material layer is 500 μm or less.

That is, the resin material forming the resin material layer is a blend of a resin having a carbon-fluorine bond (CF) or a siloxane bond (Si—O—Si) as a main chain and a resin having a hydrocarbon as a main chain. In the case of the resulting resin material, light absorption in the near infrared region due to CH, CH ₂ , CH ₃ , etc. appears depending on the proportion of the resin having the blended hydrocarbon as the main chain. When the carbon-fluorine bond or the siloxane bond is the main component, the light absorption in the near infrared region due to the hydrocarbon becomes small, so that the thickness can be increased to the upper limit of 20 mm from the viewpoint of thermal conductivity. However, when the blended hydrocarbon resin is the main component, the thickness needs to be 500 μm or less.

For blends of fluororesin or silicone rubber and hydrocarbons, the side chains of fluororesin or silicone rubber are replaced with hydrocarbons, alternate copolymers of fluororesin and silicone monomers and hydrocarbon monomers, random copolymers, etc. Block copolymers and graft copolymers are also included. Examples of the alternate copolymer of the fluorine monomer and the hydrocarbon monomer include fluoroethylene vinyl ester (FEVE), fluoroolefin-acrylic acid ester copolymer, ethylene / tetrafluoroethylene copolymer (ETFE), and ethylene. Examples include chlorotrifluoroethylene copolymer (ECTFE).

Light absorption in the near infrared region due to CH, CH ₂ , CH ₃ , etc. appears depending on the molecular weight and proportion of the hydrocarbon side chain to be substituted.
When the monomer introduced as a side chain or copolymer is a small molecule, or when the density of the introduced monomer is small, the light absorption in the near infrared region due to hydrocarbons becomes small, so from the viewpoint of thermal conductivity. It can be thickened up to the limit of 20 mm in.
When introducing a high molecular weight hydrocarbon as a side chain of a fluororesin or a silicone rubber or a monomer to be copolymerized, the thickness of the resin needs to be 500 μm or less.

In short, according to a further characteristic configuration of the radiation-cooled air-conditioned clothes of the present invention, when the resin material is a blend of a resin containing a carbon-fluorine bond and a siloxane bond and a resin having a main chain of hydrocarbons. Absorption of near infrared rays can be suppressed.

A further characteristic configuration of the radiatively cooled air-conditioned clothes of the present invention is that the resin material forming the resin material layer is a fluororesin.
The thickness of the resin material layer is 300 μm or less.

That is, from the viewpoint of practical use, the radiative cooling layer should have a thin resin material layer. The thermal conductivity of resin materials is generally lower than that of metals and glass. In order to effectively cool the object to be cooled (clothing body), the film thickness of the resin material layer should be the minimum necessary. The thicker the thickness of the resin material layer, the larger the heat radiation of the atmospheric window, and when the thickness exceeds a certain thickness, the heat radiation energy of the atmospheric window is saturated.

The film thickness of the saturated resin material layer depends on the resin material, but in the case of fluororesin, it is sufficiently saturated if it is about 300 μm. Therefore, from the viewpoint of thermal conductivity, it is desirable to suppress the film thickness of the resin material layer to 300 μm or less rather than 500 μm.
Incidentally, although the heat radiation is not saturated, sufficient heat radiation can be obtained in the window region of the atmosphere even if the thickness is about 100 μm. The thinner the thickness, the higher the thermal transmissivity and the more effectively the temperature of the object to be cooled can be lowered. Therefore, for example, in the case of a fluororesin, the thickness may be about 100 μm or less.

Further, in the case of a fluororesin, the absorption coefficient derived from the carbon-silicon bond, the carbon-chlorine bond, the carbon-oxygen bond, the ester bond, and the ether bond is larger than the absorption coefficient caused by the CF bond. Naturally, from the viewpoint of thermal conductivity, it is desirable to suppress the film thickness to 300 μm or less rather than 500 μm, but if the film thickness is further reduced to increase the thermal conductivity, a larger radiative cooling effect can be expected.
Incidentally, as an example of the fluororesin, polyvinyl fluoride (PVF) and polyvinylidene fluoride (PVDF) can be preferably used.

In short, according to the further characteristic configuration of the radiative cooling type air-conditioned clothes of the present invention, the radiative cooling effect can be improved when the resin material is fluororesin.

A further characteristic configuration of the radiated air-conditioned clothes of the present invention is that the resin material forming the resin material layer has one of carbon-chlorine bond, carbon-oxygen bond, ester bond, ether bond, and benzene ring. It is a resin material that has the above
The thickness of the resin material layer is 50 μm or less.

That is, in the case of a resin material containing a carbon-chlorine bond, a carbon-oxygen bond, an ester bond, an ether bond, and a benzene ring, the thermal radiation energy in the window of the atmosphere is saturated even if the thickness is 100 μm. Sufficient heat radiation can be obtained in the window region of the atmosphere even with a thickness of 50 μm.
The thinner the resin material, the higher the heat transmission coefficient and the more effectively the temperature of the object to be cooled can be lowered. Therefore, a resin containing a carbon-chlorine bond, a carbon-oxygen bond, an ester bond, an ether bond, and a benzene ring. In the case of, if the thickness is 50 μm or less, the heat insulating property becomes small and the object to be cooled can be effectively cooled.

The effect of thinning is other than lowering the heat insulating property and making it easier to transfer cold heat. It is the suppression of near-infrared light absorption from CH, CH ₂ and CH ₃ in the near-infrared region exhibited by resins containing carbon-chlorine bonds, carbon-oxygen bonds, ester bonds and ether bonds. If it is made thinner, the absorption of sunlight by these can be reduced, so that the cooling capacity of the radiative cooling device is increased.
From the above viewpoint, in the case of a resin containing a carbon-chlorine bond, a carbon-oxygen bond, an ester bond, an ether bond, and a benzene ring, a thickness of 50 μm or less can more effectively produce a radiant cooling effect in the sunlight. ..

In short, according to a further characteristic configuration of the radiatively cooled air-conditioned clothes of the present invention, radiative cooling is performed on a resin material having one or more of a carbon-chlorine bond, a carbon-oxygen bond, an ester bond, an ether bond, and a benzene ring. The effect can be improved.

A further characteristic configuration of the radiation-cooled air-conditioned clothes of the present invention is that the resin material forming the resin material layer is a resin material having a carbon-silicon bond.
The point is that the thickness of the resin material layer is 10 μm or less.

That is, in the case of a resin material having a carbon-silicon bond, heat radiation is completely saturated in the window region of the atmosphere even at a thickness of 50 μm, and sufficient heat radiation can be obtained in the window region of the atmosphere even at a thickness of 10 μm. The thinner the resin material, the higher the thermal transmission rate and the more effectively the temperature of the object to be cooled can be lowered. Therefore, in the case of a resin material containing a carbon-silicon bond, if the thickness is 10 μm or less, the heat insulating property is improved. It becomes smaller and can effectively cool the object to be cooled. If it is made thinner, the absorption of sunlight can be reduced, so that the cooling capacity of the radiatively cooled air-conditioned clothes is increased.

From the above viewpoint, in the case of a resin material containing a carbon-silicon bond, a thickness of 10 μm or less can more effectively produce a radiative cooling effect in a solar radiation environment.

In short, according to the further characteristic configuration of the radiatively cooled air-conditioned clothes of the present invention, the radiative cooling effect can be improved in the resin material having a carbon-silicon bond.

A further characteristic configuration of the radiantly cooled air-conditioned clothes of the present invention is that the resin material forming the resin material layer is a vinyl chloride resin or a vinylidene chloride resin.
The thickness of the resin material layer is 100 μm or less and 10 μm or more.

That is, the vinyl chloride resin (polyvinyl chloride) or vinylidene chloride resin (polyvinylidene chloride) having a thickness of 100 μm or less and 10 μm or more can obtain sufficient heat radiation in the window region of the atmosphere.
Although vinyl chloride resin or vinylidene chloride resin is slightly inferior in thermal radiation characteristics to fluororesins that can obtain large thermal radiation in the window region of the atmosphere, it is superior to other resin materials such as silicone rubber and considerably better than fluororesins. Since it is inexpensive, it is effective for inexpensively configuring a radiant cooling device whose temperature is lower than the ambient temperature in direct sunlight.

Further, since the thin-film vinyl chloride resin or vinylidene chloride resin is soft, it is not easily scratched even if it comes into contact with other substances, so that it can be maintained in a beautiful state for a long period of time. By the way, since the thin-film fluororesin is rigid, it is easily scratched by contact with other objects, and it is difficult to maintain a beautiful state.

In short, according to the further characteristic configuration of the radiatively cooled air-conditioned clothes of the present invention, it is possible to inexpensively obtain a radiative cooling layer whose temperature is lower than the ambient temperature and which is not easily scratched even in a solar radiation environment.

A further characteristic configuration of the radiatively cooled air-conditioned clothes of the present invention is that the light reflecting layer is made of silver or a silver alloy, and the thickness thereof is 50 nm or more.

That is, the light reflecting layer has the above-mentioned reflectance characteristics, that is, the reflectance characteristics of a wavelength of 0.4 μm to 0.5 μm of 90% or more and a reflectance of long waves having a wavelength of 0.5 μm of 96% or more. In order to make the light-reflecting layer, the reflective material on the radiation surface side of the light-reflecting layer needs to be silver or a silver alloy.
When sunlight is reflected with only silver or a silver alloy having the above-mentioned reflectance characteristics, the thickness needs to be 50 nm or more.

In short, according to the further characteristic configuration of the radiatively cooled air-conditioned clothes of the present invention, it is possible to accurately suppress the absorption of solar energy by the light reflecting layer and satisfactorily perform radiative cooling by the resin material layer.

A further characteristic configuration of the radiant-cooled air-conditioned clothing of the present invention is that the light-reflecting layer is a laminate of a silver or silver alloy located adjacent to the protective layer and an aluminum or aluminum alloy located on the side away from the protective layer. The point is that it is a structure.

That is, in order to give the light-reflecting layer the above-mentioned reflectance characteristics, a structure in which silver or a silver alloy and aluminum or an aluminum alloy are laminated may be used. In this case as well, the reflective material on the radiation surface side needs to be silver or a silver alloy. In this case, the thickness of silver needs to be 10 nm or more, and the thickness of aluminum needs to be 30 nm or more.

Since aluminum or an aluminum alloy is cheaper than silver or a silver alloy, it is possible to reduce the cost of the light reflecting layer while having appropriate reflectance characteristics.
In other words, it is appropriate to make the light-reflecting layer a laminated structure of silver or silver alloy and aluminum or aluminum alloy while thinning the expensive silver or silver alloy to reduce the cost of the light-reflecting layer. It is possible to reduce the cost of the light-reflecting layer while having a high reflectance characteristic.

In short, according to the further characteristic configuration of the radiatively cooled air-conditioned clothes of the present invention, it is possible to reduce the cost of the light reflecting layer while having appropriate reflectance characteristics.

It is a figure explaining the basic structure of a radiative cooling type air-conditioned clothes. It is a figure which shows the relationship between the absorption coefficient of a resin material and a wavelength band. It is a figure which shows the relationship between the light absorption rate of a resin material, and a wavelength. It is a figure which shows the emissivity spectrum of a silicone rubber. It is a figure which shows the emissivity spectrum of PFA. It is a figure which shows the emissivity spectrum of a vinyl chloride resin. It is a figure which shows the emissivity spectrum of an ethylene terephthalate resin. It is a figure which shows the emissivity spectrum of an olefin metamorphic material. It is a figure which shows the relationship between the temperature of a radiation surface and the temperature of a light reflection layer. It is a figure which shows the light absorption | light absorption spectrum of the silicone rubber and the perfluoroalkoxy fluororesin. It is a figure which shows the light absorption | light absorption spectrum of the ethylene terephthalate resin. It is a figure which shows the light reflectance spectrum of the light reflection layer based on silver. It is a figure which shows the emissivity spectrum of a fluoroethylene vinyl ether. It is a figure which shows the emissivity spectrum of vinylidene chloride resin. It is a table which shows the experimental result of a radiative cooling layer. It is a figure which shows the specific structure of the radiative cooling type air-conditioned clothes. It is a figure which shows the specific structure of the radiative cooling type air-conditioned clothes. It is a figure which shows the specific structure of the radiative cooling type air-conditioned clothes. It is a figure which shows the specific structure of the radiative cooling type air-conditioned clothes. It is a figure which shows the relationship between the light absorption rate of a resin material, and a wavelength. It is a figure which shows the relationship between the light transmittance and the wavelength of polyethylene. It is a figure explaining the structure for a test. It is a figure which shows the test result when the protective layer is polyethylene. It is a figure which shows the test result when the protective layer is the ultraviolet absorption acrylic. It is a figure which shows the emissivity spectrum of polyethylene. It is a graph which shows the experimental result of a radiative cooling cloth. It is a figure explaining another structure of a radiative cooling layer. It is a figure which shows the structure which formed the radiative cooling layer into an uneven shape. It is a figure which shows the specific example of the uneven shape of a radiative cooling layer. It is a figure which shows the specific example of the uneven shape of a radiative cooling layer.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[Basic configuration of radiatively cooled air-conditioned clothes]
As shown in FIG. 1, in the radiative cooling type air-conditioned clothes W, the blower fan 1 (of the blower unit) for flowing cooling air through the clothes main body E worn by the wearer M through between the clothes main body E and the wearer M. (Example) is provided, and a radiative cooling layer CP is attached to the outer surface of the clothes body E.
That is, the radiative cooling type air-conditioned clothes W is configured so that the clothes main body E is cooled by the radiative cooling action of the radiative cooling layer CP.

By the way, in the radiatively cooled air-conditioned clothes W illustrated, the pair of left and right blower fans 1 provided on the waist side of the back of the clothes body E sends the sucked air into the space between the clothes body E and the wearer M. It is configured as follows. Then, the air flowing in the space between the garment body E and the garment M is the gap between the collar of the garment E and the neck of the garment M, the cuffs of the garment E and the wrist of the garment M. It is configured to be discharged through the gap between the and.

By the way, the wearer generally wears clothes such as underwear and a shirt, and then wears the radiatively cooled air-conditioned clothes W on the clothes. That is, the air sucked by the blower fan 1 is flowed between the clothes worn by the wearer M and the clothes body E.
Although not shown, the front part of the clothing body E is equipped with a removable fastener for opening and closing the front part. Further, the radiative cooling cloth described later may be used for the entire clothes body E, or may be used for a part of the clothes body E.

In the present embodiment, the clothing body E is made of a cloth impregnated with a vinyl chloride resin. As the clothing body E, various materials such as polyester can be used.

The radiation cooling layer CP includes an infrared radiation layer A that emits infrared light IR from the radiation surface H, and a light reflection layer B that is located on the opposite side of the infrared radiation layer A from the side where the radiation surface H exists. The protective layer D between the infrared radiation layer A and the light reflection layer B is provided in a laminated state and is formed in a film shape.
That is, the radiative cooling layer CP is configured as a radiative cooling film.

The light reflecting layer B reflects light L such as sunlight transmitted through the infrared radiation layer A and the protective layer D, and its reflection characteristics have a wavelength of 400 nm (0.4 μm) to 500 nm (0.5 μm). The reflectance of light is 90% or more, and the reflectance of long waves having a wavelength of 500 nm or more is 96% or more.
As shown in FIG. 10, the solar spectrum exists from a wavelength of 300 nm to 4000 nm, and the intensity increases as the wavelength increases from 400 nm, and the intensity increases particularly from a wavelength of 500 nm to a wavelength of 1800 nm.

In the present embodiment, the light L includes ultraviolet light (ultraviolet rays), visible light, and infrared light, and when these are described in terms of the wavelength of light as an electromagnetic wave, the wavelength is 10 nm to 20000 nm (0). Includes electromagnetic waves of 0.01 μm to 20 μm). Incidentally, in this document, it is assumed that the wavelength range of ultraviolet light (ultraviolet rays) is between 300 nm and 400 nm.

The light reflecting layer B exhibits a reflection characteristic of 90% or more from a wavelength of 400 nm to 500 nm, and the reflectance of a long wave from a wavelength of 500 nm exhibits a reflection characteristic of 96% or more, whereby the radiation cooling layer CP (radiation cooling film) reflects light. The solar energy absorbed by the layer B can be suppressed to 5% or less, that is, the solar energy absorbed in the south and middle of the summer can be reduced to about 50 W.

The light reflecting layer B is composed of silver or a silver alloy, or is configured as a laminated structure of silver or a silver alloy located adjacent to the protective layer D and aluminum or an aluminum alloy located on the side away from the protective layer D. It is flexible and will be described in detail later.

The infrared radiating zone A is configured as a resin material layer J whose thickness is adjusted to emit heat radiation energy larger than the absorbed solar energy in the band of wavelength 8 μm to wavelength 14 μm, and the details thereof will be described later. do.

Therefore, the radiation cooling layer CP reflects a part of the light L incident on the radiation cooling layer CP on the radiation surface H of the infrared radiation layer A, and the light L incident on the radiation cooling layer CP. The light (sunlight, etc.) transmitted through the resin material layer J and the protective layer D is reflected by the light reflecting layer B and is configured to escape from the radiating surface H to the outside.

Then, heat input to the radiant cooling layer CP from the clothing body E located on the side opposite to the existing side of the resin material layer J in the light reflection layer B (for example, heat input by heat conduction from the clothing body E) is applied. It is configured to cool the clothes body E by converting it into infrared light IR by the resin material layer J and radiating it.

That is, the radiant cooling layer CP reflects the light L irradiated to the radiant cooling layer CP, and heat transfer to the radiant cooling layer CP (for example, heat transfer from the atmosphere or heat transfer from the clothing body E). ) Is configured to radiate to the outside as infrared light IR.
Further, the resin material layer J, the protective layer D, and the light reflecting layer B have flexibility, so that the radiative cooling layer CP (radiative cooling film) has flexibility.

[Overview of resin material layer]
The light absorption rate and emissivity (light emissivity) of the resin material forming the resin material layer J change depending on the thickness. Therefore, it is necessary to adjust the thickness of the resin material layer J so as not to absorb sunlight as much as possible and to emit a large amount of heat radiation in the wavelength band of the so-called atmospheric window (the band having a wavelength of 8 μm to 14 μm).

Specifically, from the viewpoint of the light absorption rate of sunlight, the thickness of the resin material layer J is such that the wavelength average of the light absorption rate of the wavelength 0.4 μm to 0.5 μm is 13% or less, and the wavelength is from 0.5 μm. The wavelength average of the light absorption rate of 0.8 μm is 4% or less, the wavelength average of the light absorption rate from 0.8 μm to 1.5 μm is within 1%, and the wavelength is 1.5 μm to 2.5 μm. It is necessary to adjust the thickness so that the wavelength average of the light absorptance up to is 40% or less and the wavelength average of the light absorptance from 2.5 μm to 4 μm is 100% or less.
In the case of such an absorption rate distribution, the light absorption rate of sunlight is 10% or less, and the energy is 100 W or less.

As will be described later, the light absorption rate of the resin material increases as the film thickness of the resin material increases. When the resin material is made into a thick film, the radiance of the window of the atmosphere becomes almost 1, and the thermal radiation emitted into the universe at that time becomes 125 W / m ² to 160 W / m ² . The sunlight absorption in the protective layer D and the light reflecting layer B is 50 W / m ² or less. If the sum of the sunlight absorption in the resin material layer J, the protective layer D and the light reflecting layer B is 150 W / m ² or less, and the atmospheric condition is good, cooling proceeds. As the resin material forming the resin material layer J, it is preferable to use a resin material having a small light absorption rate near the peak value of the sunlight spectrum as described above.

Further, the thickness of the resin material layer J needs to be adjusted so that the wavelength average of the emissivity from 8 μm to 14 μm is 40% or more from the viewpoint of infrared radiation (heat radiation).
In order to release the heat energy of sunlight of about 50 W / m2 absorbed by the protective layer D and the light reflecting layer B from the resin material layer J to the universe from the heat radiation of the resin material layer J, more heat radiation is required. The resin material layer J needs to be put out.
For example, when the outside air temperature is 30 ° C., the maximum thermal radiation of an atmospheric window of 8 μm to 14 μm is 200 W / m ² (calculated assuming an emissivity of 1). This value is obtained in fine weather, such as in high mountains, where the air is thin and dry. In lowlands, the thickness of the atmosphere is thicker than that of high mountains, so the wavelength band of atmospheric windows becomes narrower and the transmittance decreases. By the way, this is called "the window of the atmosphere becomes narrower".

In addition, the environment in which the radiative cooling layer CP (radiative cooling film) is actually used may be humid, and even in that case, the window of the atmosphere becomes narrow. The thermal radiation generated in the window area of the atmosphere when used in lowlands is estimated to be 160 W / m ² at 30 ° C. in good condition (calculated as emissivity 1). Also, as is often the case in Japan, when there is haze in the sky or when smog is present, the atmospheric window becomes even narrower, and the radiation to space is about 125 W / m ² .
In view of this situation, the wavelength average of the emissivity of 8 μm to 14 μm must be 40% or more (heat radiation intensity in the window zone of the atmosphere is 50 W / m ² ) before it can be used in the lowlands of the mid-latitude zone.

Therefore, if the thickness of the resin material layer J is adjusted so as to be within the optically specified range in consideration of the above matters, the heat output from the atmospheric window becomes larger than the heat input due to the absorption of sunlight, and the solar radiation environment. It will be possible to radiantly cool outdoors even underneath.

[Details of resin material]
The resin material includes carbon-fluorine bond (CF), siloxane bond (Si—O—Si), carbon-chlorine bond (C—Cl), carbon-oxygen bond (CO), and ester bond (R-). A colorless resin material containing COO-R), an ether bond (COC bond), and a benzene ring can be used.
For each resin material (excluding carbon-oxygen bonds), the wavelength range having an absorption coefficient in the wavelength band of the window of the atmosphere is shown in FIG.

According to Kirchhoff's law, the emissivity (ε) and the light absorption rate (A) are equal. The light absorption rate can be obtained from the absorption coefficient (α) by a relational expression of A = 1-exp (−αt) (hereinafter referred to as a light absorption rate relational expression). In addition, t is a film thickness.
That is, by adjusting the film thickness of the resin material layer J, large thermal radiation can be obtained in a wavelength band having a large absorption coefficient. In the case of radiative cooling outdoors, it is preferable to use a material having a large absorption coefficient in the wavelength band of 8 μm to 14 μm, which is the wavelength band of the window of the atmosphere.
Further, in order to suppress the absorption of sunlight, it is preferable to use a material having no absorption coefficient or a small material in the wavelength range of 0.3 μm to 4 μm, particularly 0.4 μm to 2.5 μm. As can be seen from the relational expression between the absorption coefficient and the absorptivity, the light absorptivity (emissivity) changes depending on the film thickness of the resin material.

In order to lower the temperature from the surrounding atmosphere by radiant cooling in the daytime radiant environment with direct sunlight, it has a large absorption coefficient in the wavelength band of the window of the atmosphere, and most of the absorption coefficient in the wavelength band of sunlight. If you choose a material that you do not have, the adjustment of the film thickness will hardly absorb sunlight, but it will generate a lot of heat radiation from the window of the atmosphere, that is, it will create a state where the output by radiant cooling is larger than the input of sunlight. Can be done.

Regarding the carbon-fluorine bond (CF), the absorption coefficient due to CHF and CF ₂ spreads widely over a wide band from the wavelength of 8 μm to 14 μm, which is the window of the atmosphere, and the absorption coefficient is particularly large at 8.6 μm. At the same time, regarding the wavelength band of sunlight, there is no conspicuous absorption coefficient at wavelengths of 0.3 μm to 2.5 μm, which have a large energy intensity.

As a resin material having a carbon-fluorine bond (CF),
Polytetrafluoroethylene (PTFE), a completely fluorinated resin,
Polychlorotrifluoroethylene (PCTFE) and polyvinylidene fluoride (PVDF) and polyvinyl fluoride (PVF), which are partially fluorinated resins,
Perfluoroalkoxy alkane resin (PFA), which is a fluororesin copolymer,
Ethylene tetrafluoride / propylene hexafluoride copolymer (FEP),
Ethylene / ethylene tetrafluoride copolymer (ETFE),
Ethylene / chlorotrifluoroethylene copolymer (ECTFE) can be mentioned.

Examples of the resin material having a siloxane bond (Si—O—Si) include silicone rubber and silicone resin.
In this resin, a large absorption coefficient due to expansion and contraction of the C—Si bond appears broadly around a wavelength of 13.3 μm, and an absorption coefficient due to the out-of-plane variation angle (pitch) of CSiH ₂ has a wavelength of 10 μm. It appears broadly in the center, and the absorption coefficient due to the in-plane variation angle (scissors) of CSiH ₂ appears small near a wavelength of 8 μm.

Regarding the carbon-chlorine bond (C—Cl), the absorption coefficient due to the C—Cl expansion and contraction vibration appears in a wide band with a half width of 1 μm or more centered on a wavelength of 12 μm.
Examples of the resin material include vinyl chloride resin (PVC) and vinylidene chloride resin (PVDC). In the case of vinyl chloride resin, the change in CH of Alken contained in the main chain due to the influence of electron suction of chlorine. The absorption coefficient derived from the angular vibration appears around the wavelength of 10 μm.

The ester bond (R-COO-R) and the ether bond (COC bond) have an absorption coefficient from a wavelength of 7.8 μm to 9.9 μm. Further, with respect to the carbon-oxygen bond contained in the ester bond and the ether bond, a strong absorption coefficient appears in the wavelength band of 8 μm to 10 μm.
When the benzene ring is introduced into the side chain of the hydrocarbon resin, absorption becomes widespread from 8.1 μm to 18 μm due to the vibration of the benzene ring itself and the vibration of surrounding elements due to the influence of the benzene ring.

Examples of the resin having these bonds include methyl methacrylate resin, ethylene terephthalate resin, trimethylene terephthalate resin, butylene terephthalate resin, ethylene naphthalate resin, and butylene naphthalate resin.

[Consideration of light absorption]
Consider the light absorption in the ultraviolet-visible region of the resin material having the above-mentioned bonds and functional groups, that is, the absorption of sunlight. The origin of absorption of visible light from ultraviolet light is the transition of electrons that contribute to the bond. Absorption in this wavelength range can be found by calculating the binding energy.
First, let us consider the wavelength at which the absorption coefficient occurs in the ultraviolet to visible region of a resin material having a carbon-fluorine bond (CF). The binding energies of the CC bond, CH bond, and CF bond of the basic structure portion represented by polyvinylidene fluoride (PVDF) are 4.50 eV, 4.46 eV, and 5.05 eV. They correspond to a wavelength of 0.275 μm, a wavelength of 0.278 μm, and a wavelength of 0.246 μm, respectively, and absorb light of these wavelengths.

Since the solar spectrum has only long waves having a wavelength of 0.300 μm, when a fluororesin is used, it hardly absorbs ultraviolet rays, visible rays, and near infrared rays of sunlight. The definition of ultraviolet rays is on the shorter wavelength side than the wavelength of 0.400 μm, the definition of visible light is the wavelength of 0.400 μm to 0.800 μm, the near infrared rays are in the range of 0.800 μm to 3 μm, and the mid infrared rays are 3 μm to 8 μm. The range is defined as far infrared rays having a wavelength longer than 8 μm.

The absorption rate spectrum of PFA (perfluoroalkoxy alkane resin) having a thickness of 50 μm in the ultraviolet to visible region is shown in FIG. 3, and it can be seen that it has almost no absorption rate. A slight increase in the absorption rate spectrum is observed on the wavelength side shorter than 0.4 μm, but this increase is only due to the effect of scattering of the sample used for the measurement, and the absorption rate actually increases. Not done.

Regarding the ultraviolet region of the siloxane bond (Si—O—Si), the bond energy of Si—O—Si in the main chain is 4.60 eV, which corresponds to a wavelength of 269 nm. Since the solar spectrum has only long waves having a wavelength of 0.300 μm or more, when the majority of siloxane bonds are present, it hardly absorbs ultraviolet rays, visible rays, and near infrared rays of sunlight.

FIG. 3 shows the absorption rate spectrum of the silicone rubber having a thickness of 100 μm in the ultraviolet to visible region, and it can be seen that the silicone rubber has almost no absorption rate. There is a slight increase in the absorption rate spectrum on the shorter wavelength side than the wavelength of 0.4 μm, but this increase is only due to the effect of scattering of the sample used for the measurement, and the absorption rate is actually the same. Not increasing.

Regarding the carbon-chlorine bond (C-Cl), the carbon-chlorine bond energy of Alken is 3.28 eV and its wavelength is 0.378 μm, so it absorbs a lot of ultraviolet rays in sunlight, but in the visible range. Has little absorption.
The absorption rate spectrum in the ultraviolet to visible region of a vinyl chloride resin having a thickness of 100 μm is shown in FIG. 3, and the light absorption becomes larger on the shorter wavelength side than the wavelength of 0.38 μm.
The absorption rate spectrum in the ultraviolet to visible region of the vinylidene chloride resin having a thickness of 100 μm is shown in FIG. 3, and a slight increase in the absorption rate spectrum is observed on the wavelength side shorter than the wavelength of 0.4 μm.

Resins having an ester bond (R-COO-R), an ether bond (C-OC bond), and a benzene ring include methyl methacrylate resin, ethylene terephthalate resin, trimethylene terephthalate resin, butylene terephthalate resin, and ethylene na. There are phthalate resin and butylene naphthalate resin. For example, the bond energy of the CC bond of acrylic is 3.93 eV, which absorbs sunlight having a wavelength shorter than 0.315 μm, but has almost no absorption in the visible region.

As an example of the resin material having these bonds and functional groups, the absorption rate spectrum in the ultraviolet to visible region of the methyl methacrylate resin having a thickness of 5 mm is shown in FIG. It should be noted that the exemplified methyl methacrylate resin is generally commercially available and contains a benzotriazole-based ultraviolet absorber.
Since the plate is as thick as 5 mm, the wavelength having a small absorption coefficient also becomes large, and the light absorption becomes larger on the short wave side than the long wave 0.38 μm than the wavelength 0.315.

As an example of the resin material having these bonds and functional groups, the absorption rate spectrum in the ultraviolet to visible region of an ethylene terephthalate resin having a thickness of 40 μm is shown in FIG.
As shown in the figure, the absorptivity increases as the wavelength approaches 0.315 μm, and the absorptivity sharply increases at a wavelength of 0.315 μm. As the thickness of the ethylene terephthalate resin is increased, the absorption rate due to the absorption end derived from the CC bond increases on the long wave side of the wavelength of 0.315 μm, which is the same as that of the commercially available methyl methacrylate resin. In addition, the absorption rate in ultraviolet rays increases.

If the resin material layer J uses a resin material having the above-mentioned radiation rate (light radiation rate) and light absorption rate characteristics, it is a single-layer film of one type of resin material or a multilayer film of a plurality of types of resin materials. , A single-layer film of a resin material in which a plurality of types of resin materials are blended, or a multilayer film of a resin material in which a plurality of types of resin materials are blended may be used.
The blend also includes copolymers such as alternate copolymers, random copolymers, block copolymers, and graft copolymers, and modified products in which side chains are replaced.

[Emissivity of silicone rubber]
FIG. 4 shows a radiance spectrum of a silicone rubber having a siloxane bond in an atmospheric window.
From the silicone rubber, a large absorption coefficient due to the expansion and contraction of the C—Si bond appears broadly around the wavelength of 13.3 μm, and the absorption coefficient due to the out-of-plane variation angle (pitch) of CSiH ₂ is 10 μm in wavelength. The absorption coefficient due to the in-plane variation angle (scissors) of CSiH ₂ appears small in the vicinity of the wavelength of 8 μm.
Due to this effect, the wavelength average of the emissivity with a thickness of 1 μm is 80% at a wavelength of 8 μm to 14 μm, which falls within the regulation that the wavelength average is 40% or more. As shown in the figure, the emissivity in the window region of the atmosphere increases as the film thickness increases.

Incidentally, FIG. 4 also shows the radiation spectrum when quartz having a thickness of 1 μm, which is an inorganic material, is present on silver. Quartz has only a narrow band radiation peak between wavelengths of 8 μm and 14 μm when the thickness is 1 μm.
When the thermal radiation is averaged in the wavelength range of 8 μm to 14 μm, the radiation rate of 8 μm to 14 μm is 32%, and it is difficult to show the radiative cooling performance.

The radiative cooling layer CP (radiative cooling film) of the present invention using the resin material layer J can obtain radiative cooling performance even in the infrared radiative layer A thinner than the conventional technique using an inorganic material as the light reflecting layer B. That is, when the infrared radiative layer A is formed of quartz or Tempax glass, which is an inorganic material, the radiative cooling performance cannot be obtained if the infrared radiative layer A has a thickness of 1 μm, but the resin material layer J is used. In the radiative cooling layer CP of the present invention, the radiative cooling performance is exhibited even when the resin material layer J has a thickness of 1 μm.

[PFA emissivity]
FIG. 5 shows the radiance rate of perfluoroalkoxy alkane resin (PFA) in an atmospheric window as a typical example of a resin having a carbon-fluorine bond. The absorption coefficient due to CHF and CF ₂ is widely spread over a wide band from the wavelength of 8 μm to 14 μm, which is the window of the atmosphere, and the absorption coefficient is particularly large at 8.6 μm.
Due to this effect, the wavelength average of the emissivity having a thickness of 10 μm is 45% at a wavelength of 8 μm to 14 μm, which falls within the regulation that the wavelength average is 40% or more. As shown in the figure, the emissivity in the window region of the atmosphere increases as the film thickness increases.

[Radance rate of vinyl chloride resin and vinylidene chloride resin]
FIG. 6 shows the radiation rate of vinyl chloride resin (PVC) in an atmospheric window as a typical example of a resin having a carbon-chlorine bond. Further, FIG. 14 shows the emissivity of vinylidene chloride resin (PVDC) in an atmospheric window.
Regarding the carbon-chlorine bond, the absorption coefficient due to C—Cl expansion and contraction vibration appears in a wide band with a half width of 1 μm or more centered on a wavelength of 12 μm.
Further, in the case of a vinyl chloride resin, the absorption coefficient derived from the angular vibration of CH of the alkene contained in the main chain appears around a wavelength of 10 μm due to the influence of electron suction of chlorine. The same applies to vinylidene chloride resin.
Due to these influences, the wavelength average of the emissivity with a thickness of 10 μm is 43% at a wavelength of 8 μm to 14 μm, which falls within the regulation that the wavelength average is 40% or more. As shown in the figure, the emissivity in the window region of the atmosphere increases as the film thickness increases.

[Ethylene terephthalate resin]
FIG. 7 shows the radiance of an ethylene terephthalate resin in an atmospheric window as a typical example of a resin having an ester bond or a benzene ring.
Regarding the ester bond, it has an absorption coefficient from a wavelength of 7.8 μm to 9.9 μm. Further, regarding the carbon-oxygen bond contained in the ester bond, a strong absorption coefficient appears in the wavelength band of 8 μm to 10 μm. When the benzene ring is introduced into the side chain of the hydrocarbon resin, absorption appears widely from 8.1 μm to 18 μm in wavelength due to the vibration of the benzene ring itself and the vibration of surrounding elements due to the influence of the benzene ring.
Due to these influences, the wavelength average of the emissivity with a thickness of 10 μm is 71% at a wavelength of 8 μm to 14 μm, which falls within the regulation that the wavelength average is 40% or more. As shown in the figure, the emissivity in the window region of the atmosphere increases as the film thickness increases.

[Emissivity of olefin metamorphic material]
FIG. 8 contains a carbon-fluorine bond (CF), a carbon-chlorine bond (C—Cl), an ester bond (R-COO-R), an ether bond (C—C bond), and a benzene ring. The radiation rate spectrum of the olefin-modified material, which is not present and whose main component is olefin, is shown. The sample was prepared by applying an olefin resin on the vapor-deposited silver with a bar coater and drying it.
As shown in the figure, the emissivity in the window region of the atmosphere is small, and due to this effect, the wavelength average of the emissivity with a thickness of 10 μm is 27% at wavelengths of 8 μm to 14 μm, and the wavelength average is 40% or more. not enter.

The shown emissivity is that of an olefin resin modified for application as a bar coater, and in the case of a pure olefin resin, the emissivity in the window region of the atmosphere is further small.
As described above, it does not contain a carbon-fluorine bond (CF), a carbon-chlorine bond (C—Cl), an ester bond (R-COO-R), an ether bond (C—C bond), or a benzene ring. And radiant cooling is not possible.

[Temperature of the surface of the light reflecting layer and the resin material layer]
Thermal radiation from the atmospheric window of the resin material layer J is generated near the surface of the resin material.
From FIG. 4, in the case of silicone rubber, if it is thicker than 10 μm, the heat radiation in the window region of the atmosphere does not increase. That is, in the case of silicone rubber, most of the heat radiation in the window of the atmosphere is generated in the portion within about 10 μm in depth from the surface, and the radiation in the deeper portion does not come out.

From FIG. 5, in the case of fluororesin, even if the thickness is thicker than 100 μm, there is almost no increase in thermal radiation in the window region of the atmosphere. That is, in the case of fluororesin, heat radiation in the window of the atmosphere is generated in a portion within a depth of about 100 μm from the surface, and radiation in a deeper portion does not come out.
From FIG. 6, in the case of the vinyl chloride resin, even if the thickness is thicker than 100 μm, the increase in thermal radiation in the window region of the atmosphere is almost eliminated. That is, in the case of vinyl chloride resin, heat radiation in the window of the atmosphere is generated in a portion within a depth of about 100 μm from the surface, and radiation in a deeper portion does not come out.
From FIG. 14, it can be seen that the vinylidene chloride resin is similar to the vinyl chloride resin.

From FIG. 7, in the case of the ethylene terephthalate resin, even if the thickness is thicker than 125 μm, the increase in thermal radiation in the window region of the atmosphere is almost eliminated. That is, in the case of ethylene terephthalate resin, heat radiation in the window of the atmosphere is generated at a depth of about 100 μm from the surface, and radiation at a deeper portion does not come out.

As described above, the heat radiation in the window region of the atmosphere generated from the surface of the resin material is generated in the portion where the depth from the surface is approximately 100 μm or less, and when the thickness of the resin is further increased, the heat radiation is generated. The radiatively cooled cold heat of the radiative cooling layer CP is insulated by the resin material that does not contribute to.
Consider forming a resin material layer J that ideally does not absorb sunlight at all on the light reflecting layer B. In this case, sunlight is absorbed only by the light reflecting layer B of the radiative cooling layer CP.
The thermal conductivity of the resin material is generally about 0.2 W / m / K, and when calculated in consideration of this thermal conductivity, when the thickness of the resin material layer J exceeds 20 mm, the cooling surface (in the light reflecting layer B). The temperature of the surface of the resin material layer J opposite to the existing side) rises.

Even if there is an ideal resin material that does not absorb sunlight at all, the thermal conductivity of the resin material is generally about 0.2 W / m / K, so if it exceeds 20 mm as shown in FIG. 9, the light reflecting layer B Is heated by the sunlight, and the clothes body E installed on the light reflecting layer side is heated. That is, the thickness of the resin material of the radiative cooling layer CP needs to be 20 mm or less.

FIG. 9 is a plot of the surface temperature of the radiation surface H of the radiative cooling layer (radiative cooling film) CP and the temperature of the light reflection layer B calculated assuming the southern part of a sunny day in western Japan in midsummer. .. The sunlight is AM1.5 and the energy density is 1000 W / m ² . The outside air temperature is 30 ° C., and the radiant energy varies depending on the temperature, but is 100 W at 30 ° C. The calculation is based on the assumption that the resin material layer does not absorb sunlight. Assuming no wind, the convective heat transfer coefficient is 5 W / m ² / K.

[Light absorption rate of silicone rubber, etc.]
FIG. 10 shows the light absorption rate with respect to the sunlight spectrum when the thickness of the silicone rubber having the side chain CH ₃ is 100 μm, and the light absorption rate spectrum with respect to the sunlight spectrum of the perfluoroalkoxy fluororesin having a thickness of 100 μm. .. As described above, it can be seen that both resins have almost no light absorption rate in the ultraviolet region.

Regarding silicone rubber, in the near-infrared region, the light absorption rate increases in the region on the long wave side from the wavelength of 2.35 μm. However, since the intensity of the solar spectrum in this wavelength range is weak, the solar energy absorbed is 20 W / m ² even if the light absorption rate on the long wave side from the wavelength of 2.35 μm is 100%.

The perfluoroalkoxy fluororesin has almost no light absorption rate in the wavelength range of 0.3 μm to 2.5 μm, and has light absorption on the wavelength side longer than the wavelength of 2.5 μm. However, even if the film thickness of the resin is increased and the light absorption rate on the wavelength side longer than the wavelength of 2.5 μm becomes 100%, the absorbed solar energy is about 7 W.

As the thickness (thickness) of the resin material layer J is increased, the emissivity of the window region of the atmosphere becomes approximately 1. That is, in the case of a thick film, the heat radiation radiated into space in the window area of the atmosphere when used in a low place is about 160 W / m ² to 125 W / m ² at 30 ° C. The light absorption in the light reflecting layer B is about 50 W / m ² as specified above, and the light absorption of the light reflecting layer B and the sunlight absorption when the silicone rubber or the perfluoroalkoxyfluororesin is made into a thick film are added. But it is smaller than the heat radiation radiated into space.
From the above, the maximum film thickness of the silicone rubber and the perfluoroalkoxy fluororesin is 20 mm from the viewpoint of thermal conductivity.

[About light absorption of hydrocarbon-based resin]
When the resin material forming the resin material layer J is a resin having a carbon-chlorine bond, a carbon-oxygen bond, an ester bond, an ether bond, a hydrocarbon having one or more benzene rings as a main chain, or silicone. When the hydrocarbon is a resin and has two or more carbon atoms in the side chain, absorption based on vibration such as bond angle change and expansion and contraction is observed in the near infrared region in addition to the above-mentioned ultraviolet absorption by the covalent bond electron.

Specifically, the absorption by the reference sound of the transition of CH ₃ , CH ₂ , and CH to the first excited state is from 1.6 μm to 1.7 μm in wavelength, 1.65 μm to 1.75 μm in wavelength, and 1.7 μm in wavelength, respectively. appear. Further, absorption of the combined sound of CH ₃ , CH ₂ , and CH by the reference sound appears at a wavelength of 1.35 μm, a wavelength of 1.38 μm, and a wavelength of 1.43 μm, respectively. Further, the overtones of the transition of CH ₂ and CH to the second excited state appear around the wavelength of 1.24 μm, respectively. The reference sound of the angle change and expansion / contraction of the CH bond is distributed over a wide band from a wavelength of 2 μm to 2.5 μm.

Further, in the case of having an ester bond (R—COO—R) and an ether bond (COC), there is a large absorption of light around a wavelength of 1.9 μm.
The light absorption rate resulting from these is smaller and less noticeable when the film thickness of the resin material is thin, but becomes larger when the film thickness is thick, according to the above-mentioned light absorption rate relational expression.

FIG. 11 shows the relationship between the light absorption rate and the spectrum of sunlight when the film thickness of the ethylene terephthalate resin having an ester bond and a benzene ring is changed.
As shown in the figure, as the film thickness increases to 25 μm, 125 μm, and 500 μm, the light absorption in the long wave region increases from the wavelength of 1.5 μm caused by the respective vibrations.
Further, not only the long wavelength side but also the light absorption from the ultraviolet region to the visible region is increased. This is due to the spread of the light absorption edge due to the chemical bond.

When the film thickness is thin, the light absorption coefficient increases at the wavelength having the largest absorption coefficient, but when the film thickness is thick, the absorption coefficient is weaker at the absorption edge with a wider spread than the above-mentioned light absorption coefficient relational expression. Appears next. As a result, as the film thickness increases, the light absorption from the ultraviolet region to the visible region increases.
When the thickness is 25 μm, the absorption of the sunlight spectrum is 15 W / m ² , when the thickness is 125 μm, the absorption of the sunlight spectrum is 41 W / m ² , and when the thickness is 500 μm, the absorption of the sunlight spectrum is 88 W / m 2. It is m ² .

Since the light absorption of the light reflecting layer B is 50 W / m ² according to the above regulation, when the film thickness is 500 μm, the sum of the sunlight absorption of the ethylene terephthalate resin and the sunlight absorption of the light reflecting layer B is 138 W. It becomes / m ² . The maximum value of infrared radiation in the wavelength band of the atmospheric window in the lowland summer of Japan is about 160 W, usually about 125 W, on a day when the atmospheric condition is good at 30 ° C. as described above.
From the above, when the film thickness of the ethylene terephthalate resin is 500 μm or more, the radiative cooling performance is not exhibited.

The origin of the absorption spectrum in the wavelength band of 1.5 μm to 4 μm is not the functional group but the vibration of the hydrocarbon in the main chain, and if it is a hydrocarbon resin, it behaves in the same manner as the ethylene terephthalate resin. In addition, the hydrocarbon-based resin has light absorption due to chemical bonds in the ultraviolet region, and exhibits the same behavior as the ethylene terephthalate resin in terms of visibility from the ultraviolet region.
That is, if it is a hydrocarbon resin, it behaves in the same manner as an ethylene terephthalate resin from a wavelength of 0.3 μm to 4 μm. From the above, the thickness of the hydrocarbon-based resin needs to be thinner than 500 μm.

[About light absorption of blended resin]
When the resin material is a resin material in which a resin having a carbon-fluorine bond or a siloxane bond as a main chain and a resin having a hydrocarbon as the main chain are blended, the resin having the blended hydrocarbon as the main chain is used. Light absorption in the near-infrared region due to CH, CH ₂ , CH ₃ , etc. appears according to the ratio of CH, CH 2, CH 3, and the like.
When the carbon-fluorine bond or the siloxane bond is the main component, the light absorption in the near infrared region due to the hydrocarbon becomes small, so that the thickness can be increased to the upper limit of 20 mm from the viewpoint of thermal conductivity. However, when the blended hydrocarbon resin is the main component, the thickness needs to be 500 μm or less.

For blends of fluororesin or silicone rubber and hydrocarbons, the side chains of fluororesin or silicone rubber are replaced with hydrocarbons, alternate copolymers of fluorine monomers and silicone monomers and hydrocarbon monomers, and random copolymers. , Block copolymers and graft copolymers are also included. Examples of the alternate copolymer of the fluorine monomer and the hydrocarbon monomer include fluoroethylene vinyl ester (FEVE), fluoroolefin-acrylic acid ester copolymer, ethylene / tetrafluoroethylene copolymer (ETFE), and ethylene. Examples include chlorotrifluoroethylene copolymer (ECTFE).

Light absorption in the near infrared region due to CH, CH ₂ , CH ₃ , etc. appears depending on the molecular weight and proportion of the hydrocarbon side chain to be substituted. When the monomer introduced as a side chain or copolymer is a small molecule, or when the density of the introduced monomer is small, the light absorption in the near infrared region due to hydrocarbons becomes small, so from the viewpoint of thermal conductivity. It can be thickened up to the limit of 20 mm in.
When introducing a high molecular weight hydrocarbon as a side chain of a fluororesin or a silicone rubber or a monomer to be copolymerized, the thickness of the resin needs to be 500 μm or less.

[Thickness of resin material layer]
From the practical point of view of the radiative cooling layer CP, the thickness of the resin material layer J should be thin. The thermal conductivity of resin materials is generally lower than that of metals and glass. In order to effectively cool the clothes body E, the film thickness of the resin material layer J should be the minimum necessary. The thicker the thickness of the resin material layer J, the larger the heat radiation of the atmospheric window, and when the thickness exceeds a certain thickness, the heat radiation energy of the atmospheric window is saturated.

The film thickness to be saturated depends on the resin material, but in the case of fluororesin, about 300 μm is sufficient for saturation. Therefore, from the viewpoint of thermal conductivity, it is desirable to suppress the film thickness to 300 μm or less rather than 500 μm. Further, although the heat radiation is not saturated, sufficient heat radiation can be obtained in the window region of the atmosphere even if the thickness is about 100 μm. The thinner the thickness, the higher the thermal transmissivity and the more effectively the temperature of the clothes body E can be lowered. Therefore, in the case of fluororesin, the thickness should be about 100 μm or less.

The absorption coefficient derived from the carbon-silicon bond, carbon-chlorine bond, carbon-oxygen bond, ester bond, and ether bond is larger than the absorption coefficient derived from the CF bond. Naturally, from the viewpoint of thermal conductivity, it is desirable to suppress the film thickness to 300 μm or less rather than 500 μm, but if the film thickness is further reduced to increase the thermal conductivity, a larger radiative cooling effect can be expected.
In the case of a resin containing a carbon-chlorine bond, a carbon-oxygen bond, an ester bond, an ether bond, and a benzene ring, the resin is saturated even if the thickness is 100 μm, and sufficient heat radiation is sufficiently emitted in the window region of the atmosphere even if the thickness is 50 μm. can get. The thinner the resin material, the higher the heat transmission coefficient and the more effectively the temperature of the clothing body E can be lowered. Therefore, a resin containing a carbon-chlorine bond, a carbon-oxygen bond, an ester bond, an ether bond, and a benzene ring. In the case of, if the thickness is 50 μm or less, the heat insulating property becomes small and the clothes body E can be effectively cooled. In the case of a carbon-chlorine bond, the clothes body E can be effectively cooled if the thickness is 100 μm or less.

The effect of thinning is other than lowering the heat insulating property and making it easier to transfer cold heat. It is the suppression of near-infrared light absorption from CH, CH ₂ and CH ₃ in the near-infrared region exhibited by resins containing carbon-chlorine bonds, carbon-oxygen bonds, ester bonds and ether bonds. If it is made thinner, the sunlight absorption due to these can be reduced, so that the cooling capacity of the radiative cooling layer CP is increased.
From the above viewpoint, in the case of a resin containing a carbon-chlorine bond, a carbon-oxygen bond, an ester bond, an ether bond, and a benzene ring, a thickness of 50 μm or less can more effectively produce a radiant cooling effect in the sunlight. can.

In the case of the carbon-silicon bond, the heat radiation is completely saturated in the window region of the atmosphere even if the thickness is 50 μm, and sufficient heat radiation can be obtained in the window region of the atmosphere even if the thickness is 10 μm. The thinner the resin material layer J, the higher the thermal transmissivity and the more effectively the temperature of the clothes body E can be lowered. Therefore, in the case of a resin containing a carbon-silicon bond, if the thickness is 10 μm or less, the heat insulating property is improved. Can be reduced and the clothes body E can be effectively cooled. If it is made thinner, the sunlight absorption can be reduced, so that the cooling capacity of the radiative cooling layer CP is increased.
From the above viewpoint, in the case of a resin containing a carbon-silicon bond, a thickness of 10 μm or less can more effectively produce a radiative cooling effect under sunlight.

[Details of light reflecting layer]
In order for the light reflecting layer B to have the above-mentioned reflectance characteristics, the reflective material on the existing side of the radiation surface H (the existing side of the resin material layer J) needs to be silver or a silver alloy.
As shown in FIG. 12, if the light reflecting layer B is configured based on silver, the reflectance required for the light reflecting layer B can be obtained.

When reflecting sunlight with only silver or a silver alloy with the above-mentioned reflectance characteristics, a thickness of 50 nm or more is required.
However, in order to provide the light reflecting layer B with flexibility, the thickness needs to be 100 μm or less. If it is thicker than this, it will be difficult to bend.
By the way, as the "silver alloy", an alloy in which any one of copper, palladium, gold, zinc, tin, magnesium, nickel and titanium is added to silver, for example, about 0.4% by mass to 4.5% by mass is added. Can be used. As a specific example, "APC-TR (made of FURUYA METAL)", which is a silver alloy prepared by adding copper and palladium to silver, can be used.

In order to give the light reflecting layer B the above-mentioned reflectance characteristics, a structure in which a silver or a silver alloy located adjacent to the protective layer D and an aluminum or an aluminum alloy located on the side away from the protective layer D are laminated. You may do it. Also in this case, the reflective material on the side where the radiation surface H exists (the side where the resin material layer J exists) needs to be silver or a silver alloy.
When composed of two layers of silver (silver alloy) and aluminum (aluminum alloy), the thickness of silver needs to be 10 nm or more, and the thickness of aluminum needs to be 30 nm or more.
However, in order to provide the light reflecting layer B with flexibility, the total thickness of silver and aluminum needs to be 100 μm or less. If it is thicker than this, it will be difficult to bend.

Incidentally, as the "aluminum alloy", an alloy obtained by adding copper, manganese, silicon, magnesium, zinc, carbon steel for machine structure, ittrium, lanthanum, gadrinium, and terbium to aluminum can be used.

Silver and silver alloys are vulnerable to rain and humidity and need to be protected from them, and their discoloration needs to be suppressed. Therefore, as shown in FIGS. 16 to 19, a protective layer D that protects silver is required in a form adjacent to silver or a silver alloy.
Details of the protective layer D will be described later.

[Experimental results]
Silver is formed on a glass substrate to a thickness of 300 nm, and a silicone rubber having a siloxane bond, a fluoroethylene vinyl ether having a carbon-fluorine bond, an olefin modified product (olefin modified material), and a vinyl chloride resin are placed on the bar coater. The coating was applied while controlling the film thickness, and the radiant cooling performance was measured.
The evaluation of the radiative cooling performance was carried out at an outside air temperature of 35 ° C. in late June, 3 hours after the south-center, and the temperature (° C) on the back surface of the substrate was measured after maintaining the substrate with high heat insulation. However, the vinyl chloride resin was carried out when the outside air temperature was 29 ° C. It was evaluated whether or not the radiative cooling effect was obtained depending on whether the temperature 5 minutes after installation on the jig was lower or higher than the outside air temperature.
The result of the radiative cooling test is shown in FIG.

Incidentally, the emissivity of the window region of the atmosphere of the fluoroethylene vinyl ether is as shown in FIG. The radiance of the silicone rubber is as shown in FIG. 4, the radiance of the olefin modified product (olefin modified material) is as shown in FIG. 8, and the radiance of the vinyl chloride resin is shown in FIG. It's a street.

In the case of silicone rubber having a siloxane bond, it was found that the radiative cooling capacity was exhibited at a thickness of 1 μm or more as expected from theory.
It was found that the fluoroethylene vinyl ether having a carbon-fluorine bond exhibits radiative cooling capacity at a film thickness of 5 μm, which is thinner than the theoretically predicted 10 μm. The reason for this is that not only the light absorption of the atmospheric window by the carbon-fluorine bond but also the light absorption by the ether bond of vinyl ether is added, and the light absorption rate of the atmospheric window is increased as compared with the case of each alone.
The olefin modified product (olefin modified material) has no radiative cooling ability because there is almost no heat radiation in the window region of the atmosphere.

[Specific configuration of radiative cooling type air-conditioned clothes]
In the radiative cooling layer CP, since the resin material forming the resin material layer J and the protective layer D is flexible, if the light reflecting layer B is made into a thin film, the light reflecting layer B can also be made flexible. As a result, the radiative cooling layer CP can be a flexible film (radiative cooling film).

Then, as shown in FIGS. 16 to 19, the film-shaped radiative cooling layer CP (radiative cooling film) is attached to the outer surface of the garment body E with the adhesive or adhesive connecting layer S, whereby the garment body is attached. E can be cooled.
Examples of the adhesive or adhesive used for the connection layer S include urethane-based adhesives (adhesives), acrylic-based adhesives (adhesives), EVA (ethylene vinyl acetate) -based adhesives (adhesives), and the like.

Various forms are conceivable for producing the radiative cooling layer CP in the form of a film. For example, it is conceivable to apply the protective layer D and the resin material layer J to the light reflecting layer B produced in the form of a film. Alternatively, it is conceivable to attach the protective layer D and the resin material layer J to the light reflecting layer B produced in the form of a film. Alternatively, a protective layer D is applied or pasted on the resin material layer J produced in the form of a film, and a light reflecting layer is formed on the protective layer D by vapor deposition, sputtering, ion plating, silver mirror reaction, or the like. It is conceivable to produce B.

Specifically, in the radiative cooling layer CP (radiative cooling film) of FIG. 16, when the light reflecting layer B is formed as a layer of silver or a silver alloy, or when silver (silver alloy) and aluminum (aluminum alloy) are used. In the case of two layers, the protective layer D is formed on the upper side of the light reflecting layer B, the resin material layer J is formed on the upper part of the protective layer D, and the bottom of the light reflecting layer B is formed. The lower protective layer Ds is also formed on the side.

As a method of creating the radiative cooling layer CP (radiative cooling film) of FIG. 16, the protective layer D, the light reflection layer B, and the lower protective layer Ds are sequentially coated on the film-shaped resin material layer J and integrated. A method of molding can be adopted.

In the radiation cooling layer CP (radiation cooling film) of FIG. 17, the light reflection layer B includes an aluminum layer B1 formed of an aluminum foil functioning as aluminum (aluminum alloy) and a silver layer B2 made of silver or a silver alloy. The protective layer D is formed on the upper side of the light reflecting layer B, and the resin material layer J is formed on the upper part of the protective layer D.

As a method of creating the radiative cooling layer CP (radiative cooling film) of FIG. 17, the silver layer B2, the protective layer D, and the resin material layer J are sequentially coated on the aluminum layer B1 made of aluminum foil. A method of integrally molding can be adopted.
As another production method, the resin material layer J is formed in a film shape, the protective layer D and the silver layer B2 are sequentially coated on the film-shaped resin material layer J, and the aluminum layer B1 is a silver layer. A method of pasting on B2 can be adopted.

The radiation cooling layer CP (radiation cooling film) of FIG. 18 is a case where the light reflection layer B is formed as one layer of silver or a silver alloy, or a case where the light reflection layer B is composed of two layers of silver (silver alloy) and aluminum (aluminum alloy). In, a protective layer D is formed on the upper side of the light reflecting layer B, a resin material layer J is formed on the upper part of the protective layer D, and a film layer F such as PET is formed on the lower side of the light reflecting layer B. It was done.

As a method for producing the radiation cooling layer CP (radiation cooling film) in FIG. 18, a light reflecting layer is placed on a film layer F (corresponding to a base material) formed in a film shape by PET (ethylene terephthalate resin) or the like. A method can be adopted in which B and the protective layer D are sequentially applied, integrally molded, and the separately formed film-shaped resin material layer J is adhered to the protective layer D with the glue layer N.
The adhesive (adhesive) used in the glue layer N includes, for example, urethane-based adhesive (adhesive), acrylic-based adhesive (adhesive), EVA (ethylene vinyl acetate) -based adhesive (adhesive), and the like. It is desirable to have high transparency to sunlight.

In the radiation cooling layer CP (radiation cooling film) of FIG. 19, the light reflection layer B is composed of an aluminum layer B1 that functions as aluminum (aluminum alloy) and a silver layer B2 made of silver or a silver alloy (alternative silver). , The aluminum layer B1 is formed on the upper part of the film layer F (corresponding to the base material) formed in the form of a film by PET (ethylene terephthalate resin) or the like, and the protective layer D is formed on the upper side of the silver layer B2. , The resin material layer J is formed on the upper side of the protective layer D.

As a method of creating the radiating cooling layer CP (radiating cooling film) of FIG. 19, an aluminum layer B1 is applied on the film layer F, the film layer F and the aluminum layer B1 are integrally molded, and separately. The protective layer D and the silver layer B2 are coated on the film-shaped resin material layer J to integrally form the resin material layer J, the protective layer D, and the silver layer B2, and the aluminum layer B1 and the silver layer B2 are glued together. A method of adhering with the layer N can be adopted.
The adhesive (adhesive) used in the glue layer N includes, for example, urethane-based adhesive (adhesive), acrylic-based adhesive (adhesive), EVA (ethylene vinyl acetate) -based adhesive (adhesive), and the like. It is desirable to have high transparency to sunlight.

[Details of protective layer]
The protective layer D is a polyolefin resin having a thickness of 300 nm or more and 40 μm or less, or a polyethylene terephthalate having a thickness of 17 μm or more and 40 μm or less.
Examples of the polyolefin resin include polyethylene and polypropylene.

FIG. 20 shows the absorption rates of ultraviolet rays of polyethylene, vinylidene chloride resin, ethylene terephthalate resin, and vinyl chloride resin.
Further, FIG. 21 shows the light transmittance of polyethylene suitable as a synthetic resin for forming the protective layer D.

Since the radiant cooling layer CP (radiant cooling film) exerts a radiant cooling action not only at night but also in a solar radiation environment, in order to maintain the state in which the light reflection layer B exerts a light reflection function. By protecting the light reflecting layer B with the protective layer D, it is necessary to prevent the silver of the light reflecting layer B from being discolored in a solar radiation environment.

When the protective layer D is formed of a polyolefin resin having a thickness of 300 nm or more and a form of 40 μm or less, the polyolefin resin is used in the entire wavelength range of ultraviolet rays having a wavelength of 0.3 μm to 0.4 μm. Since the synthetic resin has an ultraviolet light absorption rate of 10% or less, the protective layer D is less likely to be deteriorated by the absorption of ultraviolet rays.

Since the thickness of the polyolefin resin forming the protective layer D is 300 nm or more, the radicals generated in the resin material layer J are blocked from reaching the silver or silver alloy forming the light reflecting layer. Further, the blocking function such as blocking the moisture transmitted through the resin material layer J from reaching the silver or the silver alloy forming the light reflecting layer B is satisfactorily exhibited, and the silver forming the light reflecting layer B is formed. Alternatively, discoloration of the silver alloy can be suppressed.

Incidentally, the protective layer D formed of the polyolefin resin deteriorates while forming radicals on the surface side away from the light reflecting layer B due to the absorption of ultraviolet rays, but since the thickness is 300 nm or more, it is deteriorated. The formed radicals do not reach the light reflecting layer B, and even if they deteriorate while forming radicals, the progress of deterioration is slow due to the low absorption of ultraviolet rays, so that the above-mentioned blocking function is performed. Will be demonstrated for a long period of time.

When the protective layer D is formed of an ethylene terephthalate resin having a thickness of 17 μm or more and a form of 40 μm or less, the ethylene terephthalate resin has a wavelength of 0.3 μm to 0.4 μm as compared with the polyolefin resin. Although it is a resin material having a high light absorption rate of ultraviolet rays in the wavelength range of ultraviolet rays, since the thickness is 17 μm or more, the radicals generated in the resin material layer J form a silver or silver alloy forming the light reflecting layer B. It is intended to satisfactorily exhibit a blocking function for a long period of time, such as blocking the arrival of water and blocking the moisture transmitted through the resin material layer J from reaching the silver or silver alloy forming the light reflecting layer. Therefore, discoloration of the silver or the silver alloy forming the light reflecting layer B can be suppressed.

That is, the protective layer D formed of the ethylene terephthalate resin deteriorates while forming radicals on the surface side away from the light reflecting layer B due to the absorption of ultraviolet rays, but the thickness is 17 μm or more. The formed radicals do not reach the light reflecting layer B, and even if they deteriorate while forming radicals, the thickness is 17 μm or more, so that the above-mentioned blocking function can be exhibited for a long period of time. become.

To add an explanation, the deterioration of the polyethylene terephthalate resin (PET) is caused by the cleavage of the ester bond between ethylene glycol and terephthalic acid by ultraviolet rays to form radicals. This deterioration proceeds in order from the surface of the surface of the ethylene terephthalate resin (PET) irradiated with ultraviolet rays.

For example, when the ethylene terephthalate resin (PET) is irradiated with intense ultraviolet rays in Osaka, the ester bond of the ethylene terephthalate resin (PET) having a diameter of about 9 nm is cleaved in order from the irradiated surface per day. .. Since the ethylene terephthalate resin (PET) is sufficiently polymerized, the ethylene terephthalate resin (PET) on the cleaved surface does not attack the silver (silver alloy) of the light reflecting layer B, but the ethylene terephthalate resin. When the cracked end of (PET) reaches the light reflecting layer B silver (silver alloy), the silver (silver alloy) is discolored.

Therefore, in order to make the protective layer D durable for one year or more when used outdoors, a thickness of about 3 μm is required by integrating 9 nm / day and 365 days. In order to make the ethylene terephthalate resin (PET) of the protective layer D durable for 3 years or more, a thickness of 10 μm or more is required. A thickness of 17 μm or more is required to make it durable for 5 years or more.

When the protective layer D is formed of the polyolefin resin and the ethylene terephthalate resin, the reason for setting the upper limit of the thickness is to prevent the protective layer D from exhibiting heat insulating properties that do not contribute to radiative cooling. be. That is, since the protective layer D exhibits a heat insulating property that does not contribute to radiative cooling as the thickness increases, the protective layer D exhibits a heat insulating property that does not contribute to radiative cooling while exerting a function of protecting the light reflecting layer B. In order to avoid the above, the upper limit of the thickness will be set.

That is, when the protective layer D becomes thick, there is no demerit in preventing the silver (silver alloy) of the light reflecting layer B from being colored, but there is a problem in radiative cooling. That is, if it is made thicker, the heat insulating property of the radiative cooling material will be improved.
For example, as shown in FIG. 25, a resin whose main component is polyethylene, which is excellent as a synthetic resin forming the protective layer D, has a small emissivity in an atmospheric window, and therefore does not contribute to radiative cooling even if it is formed thick. On the contrary, thickening will increase the heat insulation of the radiative cooling material. Next, as the thickness increases, the absorption in the near-infrared region derived from the vibration of the main chain increases, and the effect of increasing the absorption of sunlight increases.
Due to these factors, the thick protective layer D is disadvantageous for radiative cooling. From such a viewpoint, the thickness of the protective layer D formed of the polyolefin resin is preferably 5 μm or less, more preferably 1 μm or less.

By the way, as shown in FIG. 18, when the glue layer N is located between the resin material layer J and the protective layer D, radicals are also generated from the glue layer N, but the protective layer D is formed. If the thickness of the polyolefin-based resin to be formed is 300 nm or more and the thickness of the ethylene terephthalate resin forming the protective layer D is 17 μm or more, the radicals generated in the glue layer N reach the light reflecting layer B. Can be suppressed for a long period of time.

[Consideration of protective layer]
In order to examine the difference in how silver is colored by the protective layer D, a sample in which the protective layer D without the resin material layer J as the infrared radiating zone A as shown in FIG. 22 is exposed is prepared. , The coloring of silver after being irradiated with simulated sunlight was investigated.
That is, as the protective layer D, two types of a general acrylic resin that absorbs ultraviolet rays (for example, a methyl methacrylate resin mixed with a benzotriazole ultraviolet absorber) and polyethylene are used as a light reflecting layer B with a bar coater. A sample coated on the film layer F (corresponding to the base material) provided with silver was formed, and the function as the protective layer D was examined. The thickness of the applied protective layer D is 10 μm and 1 μm, respectively.
The film layer F (corresponding to the base material) is formed in the form of a film by PET (ethylene terephthalate resin) or the like.

As shown in FIG. 24, when the protective layer D is an acrylic resin that absorbs ultraviolet rays well, the protective layer D is decomposed by ultraviolet rays to form radicals, and silver immediately yellows and does not function as a radiation cooling layer CP. (It absorbs sunlight and rises in temperature when exposed to sunlight like ordinary materials).
The line of 600h in the figure is a reflectance spectrum after a xenon weather test (ultraviolet light energy is 60 W / m ² ) for 600 hours (hours) under the conditions of JIS standard 5600-7-7. The 0h line is the reflectance spectrum before the xenon weather test.

As shown in FIG. 23, when the protective layer D is polyethylene having a low light absorption rate of ultraviolet rays, it can be seen that the reflectance does not decrease in the near-infrared region to the visible region. In other words, the resin whose main component is polyethylene (polyethylene resin) hardly absorbs the ultraviolet rays of the sunlight that reaches the ground, so it is difficult to form radicals even when exposed to sunlight, so it reflects light even when exposed to sunlight. Coloring of silver as layer B does not occur.
The line of 600h in the figure is a reflectance spectrum after a xenon weather test (ultraviolet light energy is 60 W / m ² ) for 600 hours (hours) under the conditions of JIS standard 5600-7-7. The 0h line is the reflectance spectrum before the xenon weather test.

The reason why the reflectance spectrum in this wavelength band undulates is the Fabry-Perot resonance of the polyethylene layer. It can be seen that this resonance position is slightly different between the 0h line and the 600h line due to the change in the thickness of the polyethylene layer due to the heat of the xenon weather test, but the ultraviolet rays derived from the yellowing of silver- No significant decrease in reflectance is observed in the visible region.

The fluororesin-based material can also be applied to the material forming the protective layer D from the viewpoint of absorbing ultraviolet rays, but when it is actually formed as the protective layer D, it is colored and deteriorated at the forming stage, so that the material forming the protective layer D is formed. Cannot be used as.
Further, silicone can also be applied to the material forming the protective layer D from the viewpoint of absorbing ultraviolet rays, but the adhesion to silver (silver alloy) is extremely poor, and it cannot be used as the material forming the protective layer D.

[Experimental results of radiative cooling cloth]
FIG. 26 shows the experimental results on how much the sensible temperature differs between the general cloth and the radiative cooling cloth provided with the radiative cooling layer CP. The sensible temperature is the temperature measured by a blackbody thermometer. The experiment date is August 19th.
The white cloth was a cloth impregnated with vinyl chloride (E65TS manufactured by Kanbo Pras Corporation) and was not breathable. As the aluminum-deposited light-shielding film, a tech mirror manufactured by Nippon Wayblock Co., Ltd. was used. The radiative cooling cloth is a laminate of a cloth impregnated with vinyl chloride and a radiative cooling layer CP (radiative cooling film).

A closed space was formed with a cloth impregnated with vinyl chloride, an aluminum-deposited light-shielding film, and a radiative cooling cloth, and the temperature of the closed space facing the sky was measured. For example, in the case of a radiative cooling cloth, it is the sensible temperature of the shoulder when a human is standing upright and the sensible temperature of the back when the human is crouching.
As shown in FIG. 26, the sensible temperature at 12 o'clock was 46.3 ° C. for the cloth impregnated with vinyl chloride, 44.1 ° C. for the aluminum vapor-deposited heat-shielding film, and 36.1 ° C. for the radiative cooling cloth.

The heat stroke index WBGT in a closed space can be calculated by the following formula.
That is, it can be calculated by WBGT = 0.7 × wet-bulb temperature + 0.3 × blackbody temperature.
From this formula, the heat stroke index of the radiative cooling cloth is 3 ° C. lower than that of the cloth impregnated with vinyl chloride and 2.4 ° C. lower than that of the aluminum vapor-deposited heat shield film at the same humidity.
Then, when the outside air is forcibly taken into the air-conditioned clothes formed of the radiant cooling cloth by the blower fan 1 (in the case of the radiant-cooled air-conditioned clothes), the humidity in the air-conditioned clothes is almost the same as the relative humidity of the outside air. Then, since the outside temperature at the same time is 35 ° C, the relative humidity is 50%, and the wet ball temperature is 26.2 ° C, the heat stroke index of the cloth white cloth impregnated with vinyl chloride is 32.2 ° C. The heat illness index of the aluminum vapor-deposited heat shield film is 31.6 ° C., and the heat illness index of the radiant-cooled air-conditioned clothes W is 29.2 ° C.

According to the guideline on heat stroke index presented by the Ministry of the Environment, exercise should be stopped in principle when the heat stroke index is 31.0 ° C or higher, and strict caution should be exercised when the heat stroke index is 28 ° C to 31 ° C. Vigorous exercise is discontinued).
Therefore, if the radiatively cooled air-conditioned clothes W having a heat stroke index of 29.2 ° C. are worn, various operations can be performed.

[Separate configuration of radiative cooling layer]
As shown in FIG. 27, the radiative cooling layer CP includes an anchor layer G on the upper part of the film layer F (corresponding to the base material), and the light reflection layer B, the protective layer D, and infrared rays are on the upper part of the anchor layer G. It may be configured to include the radiation layer A.
The film layer F (corresponding to the base material) is formed in the form of a film, for example, PET (ethylene terephthalate resin) or the like.

The anchor layer G is introduced to strengthen the adhesion between the film layer F and the light reflecting layer B. That is, if an attempt is made to directly form silver (Ag) on the film layer F, peeling may easily occur. The anchor layer G is mainly composed of acrylic, polyolefin, or urethane, and is preferably mixed with a compound having an isocyanate group or a melamine resin. It is a coating on the part that is not directly exposed to sunlight, and there is no problem even if it is a material that absorbs ultraviolet rays.
As a method for strengthening the adhesion between the film layer F and the light reflecting layer B, there is a method other than inserting the anchor layer G. For example, if the film-forming surface of the film layer F is irradiated with plasma to roughen the surface, the adhesion is enhanced.

[Consideration of connection layer]
When the radiative cooling layer CP is attached to the outer surface of the clothing body E, the thickness of the connection layer S should be 5 μm or more and 100 μm or less.
That is, the outer surface (surface) of the clothing body E is often not a mirror surface. The outer surface (material surface) of the clothing body E, which is different from the mirror surface, often has innumerable scratches and irregularities on the order of several μm.
When the μm-level unevenness existing on the outer surface (material surface) of the clothing body E is transferred to the light reflecting layer B (silver layer) of the radiative cooling layer CP, the reflectance is lowered.
Therefore, it is necessary to introduce a structure that prevents the unevenness existing on the outer surface (material surface) from being reflected in the radiative cooling layer CP. Therefore, the radiative cooling layer CP is provided with a connection layer S having a thickness of about 5 μm to 100 μm. It is advisable to join it to the outer surface of the clothes body E.

When the connecting layer S having a thickness of 5 μm or more composed of an adhesive or an adhesive is present, the connecting layer S absorbs the unevenness of the outer surface of the clothing body E, and the light reflecting layer B (silver layer) of the radiative cooling layer CP is flat. Will be.
When the light reflecting layer B (silver layer) becomes flat, it is possible to prevent a decrease in the solar reflectance (in other words, an increase in the solar absorption rate).
However, as the thickness of the connection layer S becomes thicker, the heat insulating property is improved. If the heat insulating property is improved, the cold heat of the radiative cooling layer CP is insulated, which is not good. From this point of view, an unnecessarily thick connection layer S is unnecessary, and a thickness of 100 μm is sufficient.

[Another example of radiative cooling type air-conditioned clothes]
As shown in FIG. 28, the radiative surface H of the radiative cooling layer CP may be formed in an uneven shape.
That is, for example, it may be formed in a state where the convex portion U exists on the radial surface H.
Examples of the uneven shape include a line-and-space structure in which rectangular parallelepiped convex portions U are arranged (see FIG. 29), a structure in which convex portions U of a conical column are arranged vertically and horizontally (see FIG. 30), and a triangular prism (not shown). Various configurations can be adopted, such as a structure in which the convex portions U having a pyramid shape are arranged in a line and pace manner, a structure in which the convex portions U having a rectangular parallelepiped shape are arranged vertically and horizontally, and a structure in which the convex portions U are randomly formed.
Incidentally, the height difference when the radial surface H is formed in an uneven shape is about 100 μm.

The advantage of forming the radiant surface H in an uneven shape is that the surface area of the radiant surface H increases, for example, when a fan is installed in the work place where the wearer of the radiative cooling type air-conditioned clothes W works. Can improve the cooling function by allowing the air blown by the electric fan to be ventilated to the radiating surface H.

Forming the radial surface H in an uneven shape also has an advantage in terms of appearance. When the radiant surface H (upper surface) of the radiative cooling layer CP is a mirror surface, sunlight is scattered when the radiant surface H is formed in an uneven shape, so that the radiative cooling layer CP is glaring. It will be reduced.
Even if the function of "scattering" is given to the radiating surface H, the light absorption in the silver (silver alloy) of the light reflecting layer B does not increase, so that radiative cooling can be performed satisfactorily.

[Another Embodiment]
Hereinafter, another embodiment is listed.
(1) In the above embodiment, various resin materials for forming the resin material layer J have been exemplified, but the resin materials that can be preferably used include vinyl chloride resin (PVC), vinylidene chloride resin (PVDC), and foot. Examples thereof include vinyl chloride resin (PVF) and vinylidene fluoride resin (PVDF).

(2) In the above embodiment, the case where the protective layer D is provided is illustrated, but the protective layer D may be omitted.

(3) In the above embodiment, the embodiment in which the radiation surface H of the resin material layer J is exposed is exemplified, but a hard coat covering the radiation surface H may be provided.
As the hard coat, there are UV-curable acrylic type, thermosetting acrylic type, UV-curable silicone type, thermosetting silicone type, organic-inorganic hybrid type, and vinyl chloride, and any of them may be used. An organic antistatic agent may be used as an additive.
Urethane acrylate is particularly good among UV-curable acrylics.

As a hard coat film forming method, a gravure coat method, a bar coat method, a knife coat method, a roll coat method, a blade coat method, a die coat method and the like can be used.
The thickness of the hard coat (coating film) is 1 to 50 μm, and particularly preferably 2 to 20 μm.

Further, when a vinyl chloride resin is used as the resin material of the resin material layer J, the amount of the plasticizer of the vinyl chloride resin may be reduced to use a hard vinyl chloride resin or a semi-hard vinyl chloride resin. In this case, the vinyl chloride itself of the radiation layer becomes the hard coat layer.

(4) In the radiant cooling type air-conditioned clothes W exemplified in the above embodiment, the air sucked from the outside by the blower fan 1 provided at the waist side portion of the back of the clothes body E is between the clothes body E and the wearer M. However, instead of this, the blower fan 1 may suck and discharge the air in the space between the clothes body E and the wearer M to the outside. In this case, the space between the garment body E and the garment M becomes negative pressure, the gap between the collar of the garment body E and the neck of the garment M, and the cuffs of the garment body E and the garment M. Through the gap between the wrist, the outside air flows into the space between the garment body E and the wearer M. Incidentally, in the case of the radiatively cooled air-conditioned clothes W of this form, it is preferable to provide a member forming a space through which air flows between the clothes main body E and the wearer M on the inner surface side of the clothes main body E.

The configuration disclosed in the above embodiment (including another embodiment, the same shall apply hereinafter) can be applied in combination with the configuration disclosed in other embodiments as long as there is no contradiction. The embodiments disclosed in the present specification are examples, and the embodiments of the present invention are not limited thereto, and can be appropriately modified without departing from the object of the present invention.

1 Blower A Infrared radiation layer B Light reflection layer D Protective layer E Clothes body H Radiation surface J Resin material layer U Concavo-convex part

Claims (19)

The garment body is provided with a blower that allows cooling air to flow between the garment body and the wearer.
A radiative cooling layer is attached to the outer surface of the clothing body,
The radiation cooling layer is configured to include an infrared radiation layer that emits infrared light from a radiation surface and a light reflection layer located on the opposite side of the infrared radiation layer from the side where the radiation surface exists. ,
The infrared radiant layer is a resin material layer adjusted to a thickness that emits thermal radiation energy larger than the absorbed solar energy in a band having a wavelength of 8 μm to 14 μm.
A radiatively cooled air-conditioned clothing in which the light reflecting layer is made of silver or a silver alloy. It is configured to have a protective layer between the infrared radiation layer and the light reflection layer.
The radiatively cooled air-conditioned clothing according to claim 1, wherein the protective layer is a polyolefin resin having a thickness of 300 nm or more and 40 μm or less, or a polyethylene terephthalate resin having a thickness of 17 μm or more and 40 μm or less. The radiative cooling type air-conditioned clothing according to claim 1 or 2, wherein the radiative cooling layer is attached to the outer surface of the clothing body with an adhesive or a connecting layer of an adhesive. The radiative cooling type air-conditioned clothing according to any one of claims 1 to 3, wherein an uneven portion is formed on the radiant surface of the radiative cooling layer. The one according to any one of claims 1 to 4, wherein the light reflecting layer has a reflectance of 90% or more at a wavelength of 0.4 μm to 0.5 μm and a reflectance of a long wave having a wavelength of 0.5 μm of 96% or more. Radiative cooling type air-conditioned clothes. The film thickness of the resin material layer is
The wavelength average of the light absorption rate from 0.4 μm to 0.5 μm is 13% or less, and the wavelength average of the light absorption rate from 0.5 μm to 0.8 μm wavelength is 4% or less, from 0.8 μm wavelength. It has a light absorption characteristic that the wavelength average of the light absorption rate up to a wavelength of 1.5 μm is within 1% and the wavelength average of the light absorption rate from 1.5 μm to 2.5 μm is 40% or less.
The radiative cooling type air-conditioned clothing according to any one of claims 1 to 5, which is adjusted to a thickness in a state having a thermal radiation characteristic in which the wavelength average of the emissivity of 8 μm to 14 μm is 40% or more. The resin material forming the resin material layer is selected from a resin material having at least one of a carbon-fluorine bond, a siloxane bond, a carbon-chlorine bond, a carbon-oxygen bond, an ether bond, an ester bond, and a benzene ring. The radiation-cooled air-conditioning clothing according to any one of claims 1 to 6. The main component of the resin material forming the resin material layer is siloxane.
The radiatively cooled air-conditioned clothes according to any one of claims 1 to 6, wherein the resin material layer has a thickness of 1 μm or more. The radiatively cooled air-conditioned clothing according to claim 7, wherein the resin material layer has a thickness of 10 μm or more. The radiative cooling type air-conditioned clothes according to any one of claims 1 to 9, wherein the thickness of the resin material layer is 20 mm or less. The radiative cooling type air-conditioned clothes according to claim 10, wherein the resin material forming the resin material layer is fluororesin or silicone rubber. The resin material forming the resin material layer is a resin material having a hydrocarbon as a main chain having at least one of a carbon-chlorine bond, a carbon-oxygen bond, an ester bond, an ether bond, and a benzene ring, or a side. A silicone resin having two or more carbon atoms in a chain hydrocarbon.
The radiatively cooled air-conditioned clothes according to any one of claims 1 to 9, wherein the resin material layer has a thickness of 500 μm or less. A claim that the resin material forming the resin material layer is a blend of a resin containing a carbon-fluorine bond and a siloxane bond and a resin having a main chain of hydrocarbons, and the thickness of the resin material layer is 500 μm or less. The radiant cooling type air-conditioned clothes according to any one of 1 to 9. The resin material forming the resin material layer is a fluororesin.
The radiatively cooled air-conditioned clothes according to any one of claims 1 to 9, wherein the resin material layer has a thickness of 300 μm or less. The resin material forming the resin material layer is a resin material having at least one of a carbon-chlorine bond, a carbon-oxygen bond, an ester bond, an ether bond, and a benzene ring.
The radiatively cooled air-conditioned clothes according to any one of claims 1 to 9, wherein the resin material layer has a thickness of 50 μm or less. The resin material is a resin material having a carbon-silicon bond.
The radiatively cooled air-conditioned clothes according to any one of claims 1 to 9, wherein the resin material layer has a thickness of 10 μm or less. The resin material forming the resin material layer is vinyl chloride resin or vinylidene chloride resin.
The radiative cooling type air-conditioned clothes according to any one of claims 1 to 6, wherein the thickness of the resin material layer is 100 μm or less and 10 μm or more. The radiative cooling type air-conditioned clothes according to any one of claims 1 to 17, wherein the light reflecting layer is made of silver or a silver alloy and has a thickness of 50 nm or more. The invention according to any one of claims 2 to 17, wherein the light reflecting layer has a laminated structure of silver or a silver alloy located adjacent to the protective layer and aluminum or an aluminum alloy located on a side away from the protective layer. Radiative cooling type air-conditioned clothes.

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