WO2015065134A1 - Multi-layer coating system using voids for heat shielding system and method for manufacturing same - Google Patents

Abstract

Disclosed are a multi-layer coating system and a method for manufacturing same, the multi-layer coating system comprising: layer 1 which comprises a plurality of spherical voids, which are irregularly distributed, well-separated, and have a radius of a₁, and a filler material having a refraction index of n₁ which is interposed between the spherical voids; and subsequent layers represented by the following word equation, "layer i which is positioned on top of layer i-1 and comprises a plurality of spherical voids, which are irregularly distributed, well-separated, and have a radius of a_i, and a filler material having a refraction index of n_i which is interposed between the spherical voids (wherein i is an integer larger than 1)."

Description

Multi-Layer Coating System for Heat Barrier System Using Cavities and Manufacturing Method Thereof

The present invention relates to a multi-layered coating system, and more particularly, to a multi-layer coating system for a heat blocking system using voids and a method of manufacturing the same.

Most of mankind's energy is used for heating and cooling. For example, in summer, most of the electricity bill is associated with the energy used to operate the air conditioner to keep the room temperature low, while in winter, energy is used to operate the heater to keep the room warm. Most of the energy wasted on heating and cooling can be attributed to poor insulation against heat loss. In the prior art with regard to heat resistant paint, conventional paint is converted into heat resistant paint by mixing with fines and cavities. In other similar prior art, colloidal particles are mixed with a film-forming material applied on a substrate such as window glass or glass to block infrared electromagnetic waves.

One category of prior art regarding thermal barrier technology relates to heat resistant paints. In US Pat. No. 4,463,90, glass microspheres or hollow glass extenders are mixed with conventional paint to reduce direct thermal conductivity, which greatly improves insulation against heat loss. . In one embodiment, glass microspheres with diameters ranging from approximately 50 microns to 150 microns are mixed with conventional paint, while in other embodiments, glass microspheres with diameters of approximately 100 microns Mixed with conventional paints. Otherwise, US Pat. No. 4,463,90 does not discuss any aspect of the multilayer coating structures discussed in the present invention.

In US Pat. No. 8287998, hollow microspheres selected from glass microspheres, ceramic microspheres and organic polymer microspheres with an average particle size of between 0.5 and 150 microns have a direct thermal conductivity. It is mixed with conventional paint to reduce). Further, US Pat. No. 8287998 incorporates infrared reflecting pigment materials in conventional paint mixtures to reduce thermal conductivity associated with radiative heat transfers. Otherwise, U. S. Patent No. 8287998 does not discuss any aspect of the multilayer coating structures discussed herein.

In US 2010/0203336, solar reflective roofing granules are disclosed. In one embodiment, the sun reflective granules are formed by sintering ceramic particles, which are coated with sun reflecting particles. Otherwise, US Patent 2010/0203336 does not discuss any aspect of the multilayer coating structures covered herein.

In US 2013/0108873, roofing granule forming particles are coated with a layer of nanoparticles that reflects near infrared radiation. Similarly, in US 2013/0161578, roofing granules are formed of infrared reflective inert mineral core particles with naturally occurring voids (or defects). . Otherwise, US Patent 2013/0108873 and US Patent 2013/0161578 do not discuss any aspect of the multilayer coating structures referred to herein.

In US 2008/0035021, a method of making aluminum phosphate hollow microspheres is disclosed. This US patent also shows how to use such particulates to improve insulation against heat loss. Otherwise, US 2008/0035021 does not discuss any aspect of the multilayer coating structures covered by the present invention.

In US 2007/0298242, a lens for filtering optical waves is disclosed, and metal nanoparticles having a thin film layer are formed on the lens surface thereof. Otherwise, US Patent 2007/0298242 does not discuss any aspect of the multilayer coating structures discussed herein.

In US 2007/0036985, indium tin oxide (ITO) particles are mixed with a film-forming mixture to form a thin film layer that reflects infrared waves. Otherwise, US Patent 2007/0036985 does not discuss any aspect of the multilayer coating structures represented in the present invention.

In US 2013/0266800, a method of preparing aluminum doped zinc oxide (AZO) nanocrystals is disclosed. Moreover, this patent discloses a thin film structure that reflects infrared light using AZO nano-particulates. Otherwise, US Patent 2013 / 0266800A1 does not describe any aspect of the multilayer coating structures discussed herein.

U.S. Patent No. 7760424 and U.S. Patent No. 8009351 disclose multilayer thin film structures using colloidal particles to reflect infrared electromagnetic waves. However, in US Pat. No. 7760424 and US Pat. No. 8009351, in each layer of the multilayer structure, the fine particles are arranged regularly while maintaining regular lattice spacing such as photonic crystals. In which the cavities are irregularly distributed in each layer of the multilayer coating system. U.S. Pat. No. 7,758,240 and U.S. Pat.No. 8009351 rely on Bragg's law to describe infrared reflection, whereas in the present invention, Mie scattering theory is used to describe infrared reflection. Depends on In order to ensure that visible wavelengths are highly transmitted, U.S. Pat. No. 7760424 and U.S. Pat.No. 8009351 have a limitation that the refractive index of the particulates and the refractive index of the filler material interposed in the spaces between the particulates should be nearly identical. In the present invention, the filler material and the irregularly distributed cavities need not have almost the same refractive indices. In US Pat. No. 7760424 and US Pat. No. 8009351, the infrared reflection depends largely on the angle of incidence of the incoming wave, the general properties of the photonic crystals, and the result of Bragg's law, whereas in the present invention the infrared reflection has arrived. It does not depend heavily on the angle of incidence of the wave, the general nature of the photonic crystals and the result of Bragg's law. These apparent differences clearly distinguish the present invention from US Pat. No. 7760424 and US Pat. No. 8009351.

For reference, prior arts relating to quantum dot technologies include US Pat. No. 8362684, US Pat. No. 8395042, US Pat. No. 2013/0003163, and US Pat. No. 2013/0207073. Although this prior art is not technically relevant to the present invention, there are similarities and distributions of cavities in each layer of the multilayer coating system. On the other hand, the prior art with respect to the subject matter and the quantum dot technology is basically based on different physics and both should not be considered identical.

It is an object of the present invention to provide a multilayer coating system for a thermal barrier system using cavities and a method of manufacturing the same.

The invention as set forth in claim 1 is a multilayer coating system comprising a plurality of spherical cavities having a radius a ₁ irregularly distributed and separated from each other, and a filler material of refractive index n ₁ interposed in the space between the spherical cavities. One; And the next layers represented by the following word equation: "a plurality of spherical cavities of radius a _i located on layer i-1, irregularly distributed and separated from each other, and a refractive index intervening in the space between the spherical cavities layer i comprising a filler material of n _i , where i is an integer greater than one.

In invention of Claim 2, the board | substrate is further provided under the layer 1 of Claim 1, It is characterized by the above-mentioned.

In invention of Claim 3, the board | substrate is further provided on the said layer located farthest from the layer 1 of Claim 1, It is characterized by the above-mentioned.

In the invention according to claim 4, the substrate according to claim 1 or 3 comprises one selected from the group consisting of a conductive material, a dielectric material, a semiconductor material and a fabric.

In the invention as set forth in claim 5, further comprising a sealing member for sealing the multilayer coating system according to any one of claims 1 to 3 from the outside.

In the invention according to claim 6, there is substantially no air inside the sealing member according to claim 5.

In the invention according to claim 7, the layer i according to claim 1 has a thickness different from that of the layer i-1 (where i is an integer greater than 1).

In the invention according to claim 8, the layer i according to claim 1 has the same thickness as the layer i-1 (where i is an integer greater than 1).

In the invention according to claim 9, each layer according to claim 1 has a thickness in the range of 0.01 micron to 10,000 microns.

In the invention according to claim 10, the filler material according to claim 1 comprises one selected from the group consisting of a polymeric material, a binder, a resin, a dielectric material and a ceramic material. .

In the invention according to claim 11, the refractive index of the filler material according to claim 1 satisfies n _i = n _i-1 (where i is an integer greater than 1).

In the invention according to claim 12, the refractive index of the filler material according to claim 1 satisfies n _i > n _i-1 (where i is an integer greater than 1).

In the invention described in claim 13, the radius of the spherical cavities described in claim 1 satisfies a _i > a _i-1 (where i is an integer greater than 1).

In the invention as claimed in claim 14, the radius of the spherical cavities as described in claim 1 and the refractive index of the filler material satisfy a _i = a _i-1 and n _i > n _i-1 (where i is an integer greater than 1). It features.

In the invention as set forth in claim 15, a plurality of spherical cavities of radius b are irregularly distributed and separated from each other in all the layers as set forth in claim 1, and b is b> a ₁ and b. > a _i (where i is an integer greater than 1).

In the invention as set forth in claim 16, a plurality of spherical particles having a radius c ₁ , which are irregularly distributed and separated from each other in the filler material constituting the layer 1 according to claim 15, are further included in the filler material constituting the layer i. Distributed and separated from each other, further comprising a plurality of spherical particles of radius c _i , c ₁ satisfies b> a ₁ > c ₁ , c _i b> a _i > c _i and c _i > c _i-1 (Where i is an integer greater than 1).

In the invention described in claim 17, the spherical particles according to claim 16 include one selected from the group consisting of a conductive material, a dielectric material, a semiconductor material, and a ceramic material.

In the invention described in claim 18, the filler material according to claim 1 further includes a plurality of holes therein.

In the invention described in claim 19, the plurality of holes described in claim 18 are a plurality of spherical holes having a radius of a larger size than the spherical cavities.

In the invention according to claim 20, the spherical cavity according to claim 1 has a cavity radius in the range of 0.002 microns to 500 microns.

In the invention described in claim 21, the spherical cavity according to claim 1 is formed of one selected from the group consisting of a hollow dielectric shell, a hollow conductor shell, and a hollow semiconductor shell.

The invention as set forth in claim 22, further comprising: a first electrode positioned adjacent to a further one of two faces of the layer furthest from the substrate according to claim 1; A second electrode located between the layer 1 and the substrate; A first voltage applied to the first electrode; And a second voltage different from the first voltage and applied to the second electrode.

The invention as set forth in claim 23, further comprising the steps of: (1) preparing a first solution in which a plurality of spherical cavities of radius a ₁ are mixed into a filler material of refractive index n ₁ ; (2) comprising a filler material having a refractive index n ₁ is interposed in a space between the by treatment of the substrate to the first solution, to a substrate, the irregularly distributed and separated from each other radially a plurality of the spherical joint and a spherical joint of the _first Forming a layer 1; (3) preparing an i solution (where i is an integer greater than 1), wherein a plurality of spherical cavities of radius a _i are mixed with a filler material of refractive index n _i ; And (4) treating the substrate on which the layer i-1 is formed in the i-th solution, thereby providing a space between the plurality of spherical cavities and the spherical cavities of a radius a _{i that} are irregularly distributed and separated from each other on the layer i-1. Forming a layer i comprising a filler material of intervening refractive index n _i , where i is an integer greater than one.

In the invention according to claim 24, the treatment of step (2) according to claim 23 includes a method of dipping the substrate in the first solution, a method of spin coating the first solution on the substrate, and a first And a method of spin casting a solution onto a substrate and a method of spraying the first solution onto a substrate.

In the invention according to claim 25, the process of step (4) according to claim 23 is a method of dipping the substrate on which the layer i-1 is formed in the i-th solution. Spin coating on the substrate, spin casting the solution i to the substrate on which layer i-1 is formed, and layer i-1 (where i is an integer greater than 1). It is characterized in that it is one selected from the group consisting of spraying (spraying) to the substrate.

The present invention can provide a multilayer coating system for a thermal barrier system using cavities and a method of manufacturing the same.

In order to more fully understand the present invention, reference numerals are added to the following description and the accompanying drawings, in the accompanying drawings, in which:

1 shows a schematic view of a multilayer coating system according to the invention;

2 shows an embodiment of a multilayer coating system according to the invention, showing a cross section along line AB of FIG. 1;

3 is a square grating for calculating the distance between spherical cavities of a multilayer coating system according to the present invention;

4 shows another embodiment of a multilayer coating system according to the invention, showing a cross-sectional view along line AB of FIG. 1;

5 shows yet another series of embodiments of a multilayer coating system according to the invention, showing embodiments with a substrate or sealing member;

Figure 6 shows another embodiment of a multilayer coating system according to the invention, showing an embodiment with a filler material having a plurality of holes;

FIG. 7 shows a modification of a hole formed in the filler material in the embodiment of FIG. 6;

8 shows another variation of a hole formed in the filler material in the embodiment of FIG. 6;

FIG. 9 shows another modification in which the filler material further includes a plurality of spherical particles in the embodiment of FIG. 6;

10 shows another embodiment of a multilayer coating system according to the invention, showing an embodiment with an electrode as an electromagnetic wavelength filter;

FIG. 11 is an illustration of an exemplary action of selectively blocking (or reflecting) electromagnetic radiation at a specific range of wavelengths and transmitting the remainder;

FIG. 12 is a graph of ΔQ = Q _bac -Q _ext versus wavelength, showing that a spherical cavity embedded in a medium (filler material) with refractive index n = 1.4962 is irradiated with electromagnetic radiation;

FIG. 13 shows the polar coordinates of the scattered radiation corresponding to the case of FIG. 12, showing that a spherical cavity of radius a = 200 nm embedded in a medium (filler material) with a refractive index n = 1.4962 is irradiated from the left ;

FIG. 14 shows the polar coordinates of the scattered radiation corresponding to the case of FIG. 12, showing that a spherical cavity of radius a = 200 nm embedded in a medium (filler material) with refractive index n = 1.4962 is irradiated from the left ;

15-17 show a series of embodiments of a method of making a multilayer coating system according to the present invention.

DETAILED DESCRIPTION Various exemplary embodiments will be described in detail with reference to the accompanying drawings so as to understand the specific details for carrying out the invention. The example embodiments are not intended to be limited to the particular forms disclosed herein, and these example embodiments are provided only with reference to the drawings to illustrate various aspects of the present disclosure. Exemplary embodiments include all modifications, equivalents, and alternatives falling within the scope of the present invention.

In the drawings, the thicknesses, regions, spherical particulates and spherical cavities of layers may be exaggerated for clarity, and like reference numerals refer to like elements throughout the description of the drawings. Exemplary embodiments are described herein with reference to cross-sectional views of ideal embodiments. Thus, certain shapes or regions in the exemplary embodiments should not be construed as limited to the specific shapes or regions shown in the exemplary embodiments, and those shapes or regions may not be construed as derivatives due to manufacturing errors. It can be interpreted as being included. For example, in an exemplary embodiment, the spherical particulates may appear as particles having an ellipsoidal shape that deviates slightly from the ideal sphere in a practical device.

Throughout the description, terms such as 'first subcoat layer', 'second subcoat layer', 'third subcoat layer', 'fourth subcoat layer' and the like are used to refer to specific layers in the exemplary embodiments. . Whenever terms such as 'layer 1', 'layer 2', 'layer 3', 'layer 4' and the like are more appropriate, these terms will be used in place of terms such as 'first sub-coating layer'.

To more particularly describe exemplary embodiments, various aspects will be described in detail with reference to the accompanying drawings. However, the invention is not limited to the exemplary embodiments described.

1 is a diagram illustrating an overview of an exemplary multilayer coating system 900 in accordance with the present invention. An exemplary multilayer coating system 900 includes a first subcoat layer 101, a second subcoat layer 102 located on the first subcoat layer 101, and a third subcoat layer 102 positioned on the second subcoat layer 102. And a fourth subcoat layer 104 positioned on the subcoat layer 103 and the third subcoat layer 103. Exemplary multilayer coating system 900 has four subcoat layers, first subcoat layer 101, second subcoat layer 102, third subcoat layer 103 and fourth subcoat layer 104, for brevity. Although the multilayer coating system according to the present invention does not limit the number of subcoating layers. In an exemplary multilayer coating system 900, it is assumed that electromagnetic radiation is incident from the top to the fourth subcoat layer 104.

FIG. 2 shows a first exemplary embodiment 100 as a diagram showing a cross section of an exemplary multilayer coating system 900 along a line AB. In the first exemplary embodiment 100, the second subcoat layer 102 has a larger thickness than the first subcoat layer 101, and the third subcoat layer 103 is larger than the second subcoat layer 102. The fourth subcoat layer 104 has a larger thickness than the third subcoat layer 103. However, the multilayer coating system according to the present invention, including the first exemplary embodiment 100, does not limit the thickness of each subcoating layer. For example, each of the sub-coating layers may have a thickness that is sequentially increased or may have a thickness that is sequentially decreased. In general, each subcoating layer is not limited by how large it should be, as long as it has a thickness sufficient to contain at least a spherical cavity. Each subcoating layer should have at least the same thickness as the diameter of the spherical cavity it contains. For example, each subcoating layer may have a thickness ranging from 0.01 micron to 10,000 micron.

In the multilayer coating system of the present invention, including the first exemplary embodiment 100, each subcoating layer comprises a plurality of spherical cavities arranged to be irregularly distributed. For example, in the first exemplary embodiment 100, there are a plurality of first spherical cavities 11 irregularly distributed in the first subcoat layer 101, and irregularly in the second subcoat layer 102. There are a plurality of distributed second spherical cavities 12, there is a plurality of third spherical cavities 13 distributed irregularly in the third subcoat layer 103, and in the fourth subcoat layer 104. There are a plurality of fourth spherical cavities 14 distributed irregularly.

In the multilayer coating system according to the present invention, including the first exemplary embodiment 100, the spherical cavities of each subcoating layer do not have an orderly patterned arrangement, such as lattice arrangements of crystal structures and photonic crystals. The reason for having an irregularly distributed arrangement is simple. When the spherical cavities are arranged in an ordered pattern, that is, when the cavities are arranged at a defined interstitial distance, at a completely discontinuous series of wavelength values, electromagnetic reflections are determined by the lattice constants according to Bragg's law. Will occur. Although such a feature is ideal where only discontinuous wavelength values are chosen to tune several applications, it is not suitable for applications of the kind targeted by the present invention. For example, the infrared portion of the electromagnetic spectrum associated with most thermal energy ranges in wavelength from 0.7 microns to approximately 1,000 microns. For a successful thermal barrier action, it is necessary to reflect infrared electromagnetic energy covering a wide range of wavelengths. Such actions are such that spherical cavities are arranged at regular inter-grid distances, such that they are arranged to reflect only selectively in a completely discontinuous series of wavelengths determined by lattice constants according to Bragg's law. Cannot be achieved. However, when the spherical cavities are irregularly distributed, infrared electromagnetic reflections, even if incomplete, occur over a wide range of wavelengths, which is a desirable property for successful thermal barrier action.

In the multilayer coating system of the present invention, including the first exemplary embodiment 100, each subcoating layer comprises a plurality of spherical cavities arranged to be separated from one another. Herein, an arrangement in which a plurality of spherical cavities is separated from each other refers to an arrangement in which a plurality of spherical cavities are not in contact with each other. The plurality of spherical cavities in each subcoating layer is preferably sufficiently separated so that any interaction between the two nearest neighboring spherical cavities can be largely ignored.

3 illustrates a case where the closest face-to-face separation distance between the nearest neighboring spherical cavities arranged in a two-dimensional lattice form in each sub-coating layer is 10λ (= 10λ _o / n). Where λ represents the wavelength of the electromagnetic wave inside the filler material in which the spherical cavities are arranged, λ _o is the wavelength of the electromagnetic wave in free space, and is given by λ _o = nλ, and n is the wavelength of the filler material in which the spherical cavities are arranged. Refractive index is shown. Based on this, the number and weight of spherical cavities per unit volume of each subcoating layer are calculated. The effective area A _eff occupied by one spherical cavity of radius a is A _eff = (10λ + 2a) ² . For a three-dimensional cubic lattice, the closest face-to-face separation distance between the nearest neighboring spherical cavities is 10λ, and the effective volume V _eff occupied by one spherical cavity of radius a is V _eff = (10λ + 2a) It can be expressed as ³ . Now, if the V _layer represents the volume for one of the first to fourth subcoat layers 101, 102, 103, 104 of the first exemplary embodiment 100, the total number N of spherical cavities of the subcoat layer _p is given by N _p = V _layer / V _eff or N _p = V _layer / (10λ + 2a) ³ = 1 / (10λ _o / n + 2a) ³ , and the number of spherical cavities per unit volume of the subcoating layer ( N _p / V _layer ) is given by N _p / V _layer = 1 / (10λ + 2a) ³ = 1 / (10λ _o / n + 2a) ³ . Further, the total weight of the spherical cavity of the sub-coating layer, i.e., the weight W _p of the total number of the spherical cavity of the sub-coating layer is W _p = N _p mg or ^{_{W p = 4.1888ρa 3 gV layer /}} (10λ + 2a) 3 = 4.1888 ρa ³ gV _layer / (10λ _o / n + 2a) ³ , and the weight of the spherical cavities per unit volume of the subcoating _layer (W _p / V _layer ) is W _p / V _layer = 4.1888ρa ³ g / (10λ + 2a) ³ = 4.1888ρa ³ g / (10λ _o / n + 2a) ³ , where g is the gravity constant, ρ is the effective mass density of the cavity, and m is m = ρ (4 / 3) The total effective mass of the single spherical void defined by πa ³ or m = 4.1888ρa ³ . The ideal cavity has no mass because it is hollow. However, physical cavities can be implemented using structures such as, for example, hollow shells. In this case, when the thickness of the hollow shell is very thin, the radius of the cavity can be called a, and the effective mass density p of the cavity can be calculated by dividing the volume V of the hollow shell by the total effective mass m of the hollow shell. That is, the effective mass density ρ of the physical cavity is ρ = m / V. The closest face-to-face separation distance 10λ between the closest neighboring spherical cavities shown in FIG. 3 is only an approximation to the distance sufficiently separated such that interactions between the closest neighboring spherical cavities can be ignored. Therefore any separation distances greater than 10λ are valid analysis here. In view of this, N _p and W _p are each in the range of N _p ≤ V _layer / (10λ _o / n + 2a) ³ and W _p ≤ 4.1888ρa ³ gV _layer / (10λ _o / n + 2a) ³ , respectively. (N _p / V _layer ) and (W _p / V _layer ) are respectively (N _p / V _layer ) ≤ 1 / (10λ _o / n + 2a) ³ and (W _p / V _layer ) ≤ 4.1888 ρa ³ g / (10λ _o / n + 2a) ^{3 in} the range.

In general, the scattering of electromagnetic waves in a mixture of irregularly distributed particulates requires a clear calculation of the scattering solution of a single particulate alignment. And often such scattering solutions are sufficient to account for scattering phenomena in the mixtures. For example, the transmission and reflection of light in a milk bottle or a cloud of cloud can be quantitatively explained by the Mie theory of a single milk particle for a milk bottle or a single raindrop for a cloud of clouds. In the exemplary embodiment described above, cases in which irregularly distributed cavities are embedded in a medium such as filler material have been considered. From a physical point of view, the electromagnetic scattering phenomenon in such systems is related to single particle Mie theory solutions. Details of the physics used in these details can be found in the following references: C. Bohren and D. Huffman, "Absorption and Scattering of Light by Small Particles," John Wiley & Sons, Inc., 1998 ; ISBN 0-471-29340-7

The closest face to face separation distance between the nearest neighboring spherical cavities in each subcoating layer of the multilayer coating system of the present invention is not limited to 10λ, as shown in FIG. 3. If instead another separation distance between the two nearest neighboring cavities, e.g. 5λ, can be considered as the distance at which the spherical cavities can be considered 'sufficiently separated', N _p and W _p are respectively N _p ≤ V _layer / (5λ _o / n + 2a) ³ and W _p ≤ 4.1888ρa ³ gV _layer / (5λ _o / n + 2a) ³ , given by (N _p / V _layer ) and (W _p / V _layer ) is given by (N _p / V _layer ) ≤ 1 / (5λ _o / n + 2a) ³ and (W _p / V _layer ) ≤ 4.1888ρa ³ g / (5λ _o / n + 2a) ³ , respectively. The separation distance that the two cavities can see as far enough apart to largely ignore any interaction between them depends on the type of cavities involved. For example, if the cavities are charged, a separation distance of 10λ cannot be sufficient to ignore the interactions between the two cavities. Nevertheless, the choice of 10λ in FIG. 3 would make most particulate types 'sufficiently separated'.

In the multilayer coating system according to the present invention including the first exemplary embodiment 100, a plurality of cavities of each subcoating layer may be formed in a spherical shape. Here, the plurality of spherical cavities means that the plurality of spherical cavities are spherical. Thus, when a plurality of cavities can be viewed as circular on average, some of the plurality of cavities may be included but not circular, for example, elliptical cavities.

In the multilayer coating system according to the present invention including the first exemplary embodiment 100, the plurality of spherical cavities of each subcoating layer may be formed in various materials. For example, the plurality of spherical cavities of each subcoating layer may be formed from one selected from the group consisting of a hollow dielectric shell, a hollow conductor shell and a hollow semiconductor shell. The spherical cavity can then have a cavity radius in the range of 0.002 microns to 500 microns. The spherical cavity may also be a hollow shell formed separately from the filler material and mixed into the filler material, but furthermore, the spherical cavity may be a spherical cavity formed in the filler material itself. Furthermore, the spherical cavity may be a hollow shell coated with a material selected from the group consisting of dielectric material, conductor material and semiconductor material on the outer or inner surface of the hollow shell. The list of conductive materials for forming spherical cavities in the form of hollow conductor shells includes aluminum, chromium, cobalt, copper, gold, iridium, lithium, molybdenum, nickel, osmium, Palladium, platinum, rhodium, silver, tantalum, titanium, tungsten, vanadium, alloys thereof (e.g. aluminum-copper and steel) and Mixtures thereof are included, but are not limited to these. Spherical cavities may also be formed from hollow multilayer shells, where the shell of each layer may be formed of a dielectric material, conductor material or semiconductor material. Dielectric materials or semiconductor materials with large refractive indices may also be selected as spherical cavities, but it is desirable to select conductive materials.

In the multilayer coating system according to the present invention comprising the first exemplary embodiment 100, the plurality of spherical cavities of each subcoating layer has a constant radius a. In reality it is not impossible to manufacture two different spherical cavities with the same radius size, but in view of the extremely difficult radius, radius a should be seen as referring to the average radius of a plurality of spherical cavities. Thus, among the plurality of spherical cavities having a radius a on average, there may be cavities having a radius different from the radius a. For example, in the first subcoat layer 101 a ₁₁ is the average radius size for the plurality of first spherical cavities 11, a ₁₂ is the average radius size for the plurality of second spherical cavities 12, a ₁₃ Is the average radius size for the plurality of third spherical cavities 13 and a ₁₄ is the average radius size for the plurality of fourth spherical cavities 14. In addition, the spherical cavities of each subcoating layer may have a different radius from the spherical cavities of the other subcoating layer. In the first exemplary embodiment 100, the spherical cavities of the first subcoat layer 101 comprise one type of cavities having a radius a _11, and the spherical cavities of the second subcoat layer 102 have a radius a comprises a single type of joint with a _12, a third spherical joint of the sub-coating layer 103 comprise a single type of joint with a radius a _13, a spherical joint of the fourth sub-coating layer 104 are the radius a One type of cavities with ₁₄ . Where a ₁₁ <a ₁₂ <a ₁₃ <a ₁₄ .

In a multilayer coating system according to the present invention comprising an exemplary first embodiment 100, each subcoating layer comprises a filler material of refractive index n interposed in a space between a plurality of spherical cavities. The filler material of each subcoating layer may have a different refractive index from that of the other subcoating layer or may have the same refractive index. Even if the filler materials of the sub-coating layer are identical to each other, the refractive indices may be formed differently, and even if the filler materials are different from each other, the refractive indices may be identical. In an exemplary first embodiment 100, the first subcoat layer 101 comprises a first filler material ₅₁ of refractive index n ₅₁ , and the second subcoat layer 102 has a second filler of refractive index n ₅₂ . The third subcoat layer 103 comprises a third filler material ₅₃ of refractive index n ₅₃ , and the fourth subcoat layer 104 comprises a fourth filler material ₅₄ of refractive index n 54. It includes. The refractive indices of the first to fourth filler materials 51, 52, 53, and 54 are equal to each other. That is, n ₅₁ = n ₅₂ = n ₅₂ = n ₅₄ .

In the multilayer coating system according to the present invention comprising the first exemplary embodiment 100, the filler material included in each sub-coating includes dielectric materials, ceramic materials, composite materials (composite mixtures) and polymers. It may be selected from the group consisting of materials. These lists include paints, clays, glues, cements, asphalts, polymers, gelatins, glasses, resins, binders, oxides, and combinations thereof. But not limited to. The list of composite materials includes paints, clays, adhesives, cements, etc. The list of polymeric materials includes agarose, cellulose, epoxy, hydrogel, polyacrylamide, polyacrylate, poly-diacetylene, Polyepoxide, polyether, polyethylene, polyimidazole, polyimide, polymethylacrylate, polymethylmethacrylate, poly Peptides, polyphenylene-vinylene, polyphosphate, polypyrrole, polysaccharides, polystyrene, polysulfone, polythiophene , Polyurethane, polyvinyl, and the like. Filler materials (51, 52, 53, 54) include agarose, cellulose, epoxy, hydrogel, silica gel, water glass (or sodium silicate) sodium silicate), silica glass, siloxane and the like. Various resins include synthetic resins such as acrylic and vegetable resins such as mastic. The list of oxides based on dielectric materials includes aluminum oxide, beryllium oxide, copper (I) oxide, copper (II) oxide, dysprosium oxide ), Hafnium (IV) oxide, lutetium oxide, magnesium oxide, scandium oxide, silicon monoxide, silicon dioxide, tantalum pentoxide ( tantalum pentoxide, tellurium dioxide, titanium dioxide, yttrium oxide, ytterbium oxide, zinc oxide, zirconium dioxide But not limited to.

In the multilayer coating system according to the present invention comprising the first exemplary embodiment 100, where the number of irregularly distributed spherical cavities in each sub-coating is very large and the radius of each spherical cavity is very small, Each subcoat layer has a structure similar to an aerogel structure. Aerogels are synthetic porous materials.

4 shows a cross-sectional view along line AB of the multilayer coating system 900 of FIG. 1, showing a second exemplary embodiment 300. In a multilayer coating system according to the present invention comprising an exemplary second embodiment 300, the size distribution of the spherical cavities in each subcoating layer is the same as the size distribution of the spherical cavities of the other subcoating layer but the filler of each subcoating layer. The material may have a different refractive index than the filler material of the other subcoating layer. In this multilayer coating system, the spherical cavities of each subcoating layer have the same size distribution, but since each filler material of each subcoating layer has a different refractive index, each subcoating layer exhibits different characteristics.

In the second exemplary embodiment 300, the first spherical cavities 15 of one radius size are irregularly distributed across the first to fourth subcoat layers 301, 302, 303, 304, The refractive indices for the first to fourth sub-coating layers 301, 302, 303, and 304 satisfy n ₆₁ <n ₆₂ <n ₆₃ <n ₆₄ , and n ₆₁ , n ₆₂ , n ₆₃ and n ₆₄ are each the first To refractive indexes for the fourth filler material 61, 62, 63, 64.

The multilayer coating system based on the second exemplary embodiment 300 suffers internal reflections at the interfaces of the subcoating layers due to different refractive indices for the subcoating layers. Such internal reflections inevitably lead to self-heating of the multilayer coating system.

The multilayer coating system according to the present invention may further include a substrate or a sealing member. Substrates may be arranged at various locations, such as below or above the subcoating layer arranged at the bottom of the multilayer coating system. The sealing member may also surround the multilayer coating system to seal the multilayer coating system from the outside. In a third embodiment, which is illustratively shown in FIG. 5A, the substrate 10 is arranged under the first subcoat layer 401. Substrate 10 may also be arranged over a layer that is furthest from first subcoat layer 401, such as fourth subcoat layer 404, although not explicitly shown in FIG. 5. In the fourth embodiment shown by way of example in FIG. 5B, the substrate 10 is arranged both below the first subcoat layer 401 and above the fourth subcoat layer 404. On the other hand, in the fifth embodiment exemplarily shown in FIG. 5C, the multilayer coating system including the substrate 10 is surrounded by the sealing member 80. This sealing member 80 is arranged to surround the multilayer coating system to seal the multilayer coating system from the outside. In addition, the inside of the sealing member 80 may be discharged to the outside to maintain the vacuum in the absence of air. In the exemplary third to fifth embodiments, the first to fourth subcoat layers 401, 402, 403, and 404 are provided with the first to fourth filler materials 61, 62, 63, and 64, respectively. Spherical cavities 15 of one size are irregularly distributed and separated from each other across the first to fourth filler materials 61, 62, 63, 64.

The multilayer coating system of the present invention, including exemplary first and second embodiments 100 and 300, can be applied directly to any surfaces. These include surfaces found in houses, household appliances, windows, cars, fabrics, clothing, papers, electronics, ceramic products, and the like. Thus, if the third exemplary embodiment of FIG. 5A represents a cross sectional view of a paint as a multilayer coating system applied to a wall, the substrate 10 represents a wall, and if the fourth exemplary embodiment of FIG. 5B is a fabric Substrate 10 represents a fabric, if a cross-sectional view of a coating system applied to the substrate, and if the third exemplary embodiment of FIG. 5A represents a cross-sectional view of a coating system applied to a window pane, the substrate 10 may Indicates.

The materials for the substrate 10 may be selected from the group consisting of conductive materials, dielectric materials, ceramic materials, composite materials, semiconductor materials, polymeric materials and fabrics. Here, ceramic materials, composite materials, polymeric materials and fabrics are mentioned as if they are other materials than conductive materials, dielectric materials or semiconductor materials. To eliminate the possibility of misunderstandings, all materials can be classified into three materials: conductive materials, dielectric materials and semiconductor materials. Now, depending on the actual components of the material, each of the ceramic materials, composite materials, polymeric materials and fabrics can be classified as conductive materials, dielectric materials or semiconductor materials. Nevertheless, whenever, for example, the term 'dielectric material' or 'dielectric' is referred to in the description before or after this text, the term is referred to as ceramic materials, composite materials, polymeric materials or fabrics classified as dielectric materials. It will be understood to include all materials having the properties of a dielectric, including these. Similarly, whenever the term 'conductive material' or 'conductor' is mentioned in the description, the term is a conductor, including ceramic materials, composite materials, polymeric materials or fabrics, which are classified as conductive materials. It will be understood to include all materials. And whenever the term 'semiconductor material' or 'semiconductor' is mentioned in the description, the term is any semiconductor material, including ceramic materials, composite materials, polymeric materials or fabrics classified as semiconductor materials. It will be understood to include them.

The list of conductive materials that can be used to form the substrate 10 includes aluminum, chromium, cobalt, copper, gold, iridium, lithium, molybdenum, nickel, osmium, palladium, platinum, rhodium, silver, tantalum, titanium, tungsten, Vanadium, alloys thereof (eg, aluminum-copper and steel) and mixtures thereof, including but not limited to. The list of composite materials that can be used to form the substrate 10 includes concrete, asphalt-concrete, fiber-reinforced polymers, carbon-fibre reinforced plastics, glass-reinforced plastics, reinforced rubbers. Laminated woods, plywood, paper, fiber glass, bricks, and various composite glasses. The list of polymeric materials that can be used to form the substrate 10 includes polyacrylamide, polyacrylate, poly-diacetylene, polyepoxide, polyether ( polyether, polyethylene, polyimidazole, polyimide, polymethylacrylate, polymethylmethacrylate, polypeptide, polyphenylene-vinylene (polyphenylene-vinylene), polyphosphate, polypyrrole, polysaccharide, polystyrene, polysulfone, polythiophene, polyurethane, polyvinyl ) And the like, but are not limited thereto. Substrate 10 also includes other polymeric materials such as agarose, cellulose, epoxy, hydrogel, silica gel, silica glass, siloxane, and the like. Can be formed from them. The list of fabrics that can be used to form the substrate 10 includes animal textiles, plant textiles, mineral textiles, synthetic textiles and combinations thereof. Included.

In the multilayer coating system according to the present invention, a plurality of holes irregularly distributed in the filler material of the sub-coating layer and separated from each other may be further included. A plurality of holes contained in such a filler material may be provided in every subcoat layer or some subcoat layers forming a multilayer coating system. These plurality of holes may be smaller or larger than the plurality of spherical cavities of the subcoating layer. Furthermore, the plurality of holes may be spherical holes or like amorphous holes like the plurality of spherical cavities. The plurality of holes provided in the filler material may improve the scattering efficiency of the radiation incident on the multilayer coating system or improve the thermal conductivity reduction rate.

The sixth embodiment 100 ′ exemplarily shown in FIG. 6 is a modification of the first exemplary embodiment 100, and in the sixth exemplary embodiment 100 ′, the first to fourth subs. A plurality of holes 25 'are formed in the first to fourth filler materials 51', 52 ', 53', and 54 'included in the coating layers 101', 102 ', 103', and 104 ', respectively. have. The plurality of holes 25 ′ are formed to be smaller in size than the first to fourth spherical cavities 11, 12, 13, 14. The plurality of holes 25 'may be chemically or naturally generated bubbles when forming the first to fourth filler materials 51', 52 ', 53', 54 '. For example, when the first to fourth filler materials 51 ', 52', 53 ', and 54' are formed of polyurethane foam, chemically generated bubbles are present.

FIG. 7 shows a variation of the holes 25 ′ within the fourth filler material 54 ′ included in the fourth subcoat layer 104 ′ of the sixth exemplary embodiment 100 ′. In this variant of FIG. 7, a variant is shown in which the plurality of holes 25 ′ in the filler material are larger in size than the fourth spherical cavity 14. In this case, the filler material may have a shape such as Swiss cheese.

8 shows a plurality of holes 25 ′ in the fourth filler material 54 ′ included in the fourth sub-coating layer 104 ′ of the sixth exemplary embodiment 100 ′ and other variations thereof. Is shown. In this variant of FIG. 8, the plurality of holes 25 ″ inside the fourth filler material 54 ′ have spherical shapes of radius b having a larger size than the fourth spherical cavity 14. Such a large plurality of spherical holes 25 ″ may be realized, for example, by embedding large hollow spherical shells into the filler material or forming large spherical cavities in the filler material itself.

FIG. 9 illustrates another variation of the plurality of holes 25 ′ within the fourth filler material 54 ′ included in the fourth subcoat layer 104 ′ of the sixth exemplary embodiment 100 ′. Is shown. In this modification of FIG. 9, a plurality of holes 25 ″ of radius b having a larger size than the plurality of fourth spherical cavities ₁₄ of radius a ₁₄ are formed in the fourth filler material 54 ′. In addition, there are additionally a plurality of fourth spherical particles ₂₄ having a radius c _{24 that} are irregularly distributed and separated from each other in the fourth filler material 54 '. Here, the radius c ₂₄ of the fourth spherical particle ₂₄ is smaller than the radius b of the spherical hole and the radius a ₁₄ of the fourth spherical cavity 14. That is, it satisfies b> a ₁₄ > c ₂₄ . Although not explicitly shown in FIG. 9, the first to third filler materials included in the first to third subcoat layers 101 ′, 102 ′, and 103 ′ of the sixth exemplary embodiment 100 ′, respectively, As a further modification of the plurality of holes 25 'formed in the interiors 51', 52 ', 53', respectively, the plurality of first spherical cavities having a radius a ₁₁ in the first filler material 51 ' A plurality of holes 25 ″ of radius b having a larger size than (11) as well as a plurality of first spherical particles ₂₁ of radius c ₂₁ are irregularly distributed and separated from each other, and the second filler material The plurality of second spherical particles ₂₂ of radius c ₂₂ as well as the plurality of holes 25 ″ of radius b having a size larger than 52 of the plurality of second spherical cavities ₁₂ of radius a ₁₂ . they are randomly distributed and are separated from each other, and the third filler material (53 ') a plurality of radius b with a larger size than the plurality of third rectangular cavity 13 of the radius ₁₃ to a Holes 25 ″ are of course irregularly distributed and separated from the plurality of third spherical particles _{23 having} a radius c ₂₃ . Here, each radius of the first to third spherical particles 21, 22, 23 is the same as the radius of the fourth spherical particle 24, b> a ₁₁ > c ₂₁ , b> a ₁₂ > c ₂₂ and b> satisfies a ₁₃ > c ₂₃ Further, each radius of the first to fourth spherical particles 21, 22, 23, 24 satisfies c ₂₁ <c ₂₂ <c ₂₃ <c ₂₄ with each other. In the sixth exemplary embodiment 100 ′, the plurality of holes 25 ′ are shown to be spherical in the first to fourth filler materials 51 ′, 52 ′, 53 ′, and 54 ′. It is not limited to this. For example, the plurality of holes 25 'included in the first to fourth filler materials 51', 52 ', 53', and 54 'may be amorphous rather than spherical. The seventh embodiment 500 is a modification of the first exemplary embodiment 100 and shows that the electrodes constituting the activated electromagnetic wavelength filter are provided. The starting point of the reflection area here can be changed by an applied electric field. In the seventh exemplary embodiment 500, the first electrode 5 and the first sub-coating layer adjacent to the surface located farthest from the first sub-coating layer 101 among the two surfaces of the fourth sub-coating layer 104. A second electrode 6 positioned between the 101 and the substrate 10 is provided, and a first voltage is applied to the first electrode 5 and a second voltage is applied to the second electrode 6. The first electrode 5 or the second electrode 6 is limited to the surface located farthest from the first sub-coating layer 101 of the two surfaces of the fourth sub-coating layer 104 or the first electrode 5 and the first electrode 5. The first sub-coating layer 101 and the substrate 10 are not limited to each other and may be arranged at various positions as necessary. The electric field between the first and second electrodes 5, 6 is generated by applying a bias voltage to these electrodes. Semiconductor materials react like dielectric materials in the absence of an electric field. However, when exposed to electric fields, semiconductor materials react like conductive materials. Such a property can be used to effectively control the wavelength at which electromagnetic waves begin to reflect. For example, the value of λ ₄ in reference numeral 504 of FIG. 11 to be described later may be changed by adjusting the strength of an electric field exposed to the sub-coating layer corresponding to 504.

The first and second electrodes 5, 6 of the seventh exemplary embodiment 500 may be formed of planar conductors that are transparent to the wavelengths of interest. For example, in the case of infrared reflectors, the first electrode 5 should be transparent to the infrared electromagnetic waves of interest. Moreover, if the multilayer coating system shown in the seventh exemplary embodiment 500 is optically transparent, the infrared waves of interest as well as the first and second electrodes 5, 6 are both optically transparent as well. It must pass through.

In general, the first electrode 5 or the second electrode 6 or both may be arranged such as a grid or grating structures or an array of holes or squares or the like. It can be patterned into more complex patterns. When the electrodes are patterned into such structures, the infrared wavelengths and visible light of interest can be transmitted through the openings of the patterned electrodes. If the electrodes are patterned with openings, the conductive materials for the electrodes are not limited to optically transparent conductors that transmit infrared wavelengths of interest, but any conductive materials may be used.

The operation of the multilayer coating system according to one or more exemplary embodiments is described in detail below.

FIG. 11 is a schematic diagram illustrating the action of transmission and reflection in a physical (real) multilayer coating system 100 and other ideal multilayer coating systems 100. Although the transmission and reflection actions shown in FIG. 11 are too ideal for a physical multilayer coating system, it provides a concise description of how wavelengths are selectively filtered in a multilayer coating system. It will be shown later that the physical multilayer coating system also exhibits equivalent properties as shown in FIG. 11. With this in mind, the following describes the effects of transmission and reflection in an ideal multilayer coating system.

An ideal multilayer coating system has ideal subcoating layers. Thus, the ideal multilayer coating system 100 has ideal first to fourth subcoat layers 101, 102, 103, 104. The actions of transmission and reflection in the ideal multilayer coating system 100 are shown in FIG. 11, and reference numeral 501 illustrates the action of transmission and reflection associated with the ideal first subcoat layer 101 and reference numeral 504. Describes similar operations for the ideal fourth subcoat layer 104. The description of the other two actions, although not explicitly indicated in FIG. 11, may be easily associated with the ideal second and third subcoat layers 102, 103.

In an ideal fourth subcoating layer 104, incident electromagnetic waves of wavelength λ are completely transmitted for λ <λ ₄ , fully reflected for λ ₄ ≤ λ ≤ λ _c , and partially transmitted and partially for λ> λc. Is reflected. Sub-coating layers with such wavelength filter characteristics are usefully applied to window panes where it is very necessary to reflect thermal or infrared electromagnetic waves and transmit electromagnetic waves of the visible spectrum and wavelengths used in the broadcast communications industry.

The width of the reflective area in the subcoat layer is limited. For an ideal fourth subcoat layer 104, the width of the reflective region is given by Δλ = λ _c -λ ₄ . In general, the physical subcoat layer has a very narrow width Δλ with respect to the reflective region. For this reason, a single subcoating layer is often not enough to block all unwanted wavelengths of the infrared spectrum in thermal barrier applications. Fortunately, the reflective area of the subcoating layer can be varied within the wavelength range by adjusting the diameters of the spherical cavities provided in the subcoating layer. To illustrate this, reference is made to reference numeral 501 in FIG. 11 that illustrates the effects of transmission and reflection in the ideal first subcoat layer 101. The result of '501' can be compared with the result of '504' which describes the effects of transmission and reflection in the ideal fourth subcoat layer 104 for larger diameter sized spherical cavities. Comparing both, the starting point of the reflection area at '501' occurs at λ = λ ₁ , where λ ₄ > λ ₁ . The change in the initial point of the reflective region at 501 is a result of the smaller first spherical cavity 11 distributed irregularly inside the first subcoat layer 101. In the first exemplary embodiment 100, the radii of the first to fourth spherical cavities 11, 12, 13, 14 of the first to fourth subcoat layers 101, 102, 103, 104 are a _11. <a ₁₂ <a ₁₃ <a ₁₄ , and such an arrangement of spherical cavities of an ideal multilayer coating system 100 exhibits the transmissive and reflective actions shown in FIG. 11.

The single subcoat layer is not sufficient to reflect all of the unwanted wavelengths due to the Δλ of the finite width for its reflection area. However, the first through fourth subcoat layers 101, 102, 103, 104 can be stacked together to form a multilayer coating system having a larger effective width (Δλ) _eff for the reflective region. For example, an ideal multilayer coating system 100 in which transmissive and reflective actions are shown in FIG. 11 has an effective width of (Δλ) _eff = λ _c -λ ₁ for its reflective area. In an ideal multilayer coating system 100, any electromagnetic waves of undesired wavelengths that are not reflected by the fourth subcoat layer 104 are followed by the first to third subcoat layers 101, 102, 103. Eventually it will be reflected. In FIG. 11 reflected waves in the wavelength range λ ₁ ≦ λ ≦ λ ₄ are not confined inside the multilayer coating system 100 because there are no reflective regions on the travel path for these electromagnetic waves. For example, it is assumed that electromagnetic waves in the wavelength range λ ₁ ≦ λ ≦ λ ₂ are reflected by the first subcoat layer 101. Such reflected electromagnetic waves travel across the second to fourth subcoat layers 102, 103, 104 without internal reflection and finally exit the multilayer coating system 100. Since there is no reflection area on the travel path, internal reflection does not occur. Also for that reason any reflected electromagnetic waves in the wavelength range λ ₁ ≦ λ ≦ λ ₂ will not cause magnetic heating in the multilayer coating system. However, because electromagnetic waves in the wavelength range λ> λ _c travel across the subsequent subcoat layers, some are transmitted and some are reflected. Such electromagnetic waves are internally reflected at the interfaces between the subcoats. As a result, these electromagnetic waves cause self heating of the multilayer coating system 100. Fortunately, electromagnetic waves in the wavelength range λ> λ _c are not as active as those in the wavelength range λ ≤ λ ₄ . It is negligible that electromagnetic waves in the wavelength range λ> λ _c cause heating of the multilayer coating system.

In the foregoing descriptions, the multilayer coating system has been irradiated on top. In the first exemplary embodiment 100, the topmost portion is the fourth subcoat layer 104 and the bottommost portion is the first subcoat layer 101. The multilayer coating system 100 may also be irradiated at the bottom and many of the transmission and reflection actions of the basic electromagnetic waves in this regard can still be described as shown in FIG. 11. For example, incident electromagnetic waves with wavelengths satisfying 0 <λ <λ ₁ are transmitted completely across the sub-coating layers, while incident electromagnetic waves with wavelengths satisfying λ> λ _c are partially transmitted and partially reflected. However, major modifications in the transmission and reflection actions occur when the direction of the incident electromagnetic wave is reversed in FIG. 2. Although incident electromagnetic waves with wavelengths satisfying λ ₁ ≤ λ ≤ λ ₄ are still fully reflected, the incident electromagnetic waves with wavelengths satisfying λ ₄ <λ ≤ λ _c in FIG. Because they are reversed, some are reflected and some are transmitted. Partially transmitted electromagnetic waves in regions A, B and C experience internal reflections generated between different subcoat layers. Such internal reflections will cause self heating of the multilayer coating system.

In the following, the transmissive and reflective actions of the physical multilayer coating system are described in detail.

The physical first subcoat layer 104 does not have transmissive and reflective regions so clearly outlined as shown at 504 as opposed to the ideal first subcoat layer 104. However, when the physical subcoating layers are stacked together to form a multilayer coating system, the resulting transmissive and reflective actions exhibit most of the properties described with reference to FIG. 11 for an ideal coating system.

In FIG. 12, spherical cavities having three different radii, a = 200 nm, a = 450 nm and a = 700 nm, are embedded in a medium (filler material) with refractive index n = 1.4962 and intensity I A graph of each ΔQ obtained for the case of irradiation with the incident electromagnetic wave of _o is shown. Here, ΔQ = Q _bac -Q _ext is a difference function, Q _bac is a backward scattering efficiency factor or back-scattering efficiency factor, Q _ext is an extinction efficiency factor. Mie theory was used to calculate Q _bac and Q _ext . 12, it can be easily seen that each ΔQ graph has two distinct regions. The first region I exhibits the characteristic that ΔQ has a negative value (ΔQ <0), while the second region II exhibits the characteristic of ΔQ having a positive value (ΔQ> 0). Although not explicitly shown in FIG. 12, for waves with sufficiently large wavelengths the value of ΔQ approaches zero. The region where ΔQ approaches zero can be seen as the third region (III).

The correspondence between the regions of each ΔQ graph of FIG. 12 and the regions of the transmissive and reflective actions shown at 504 in FIG. 11 depends on the wavelengths selected in the first and second regions I, II. Will appear. In the calculation, it is assumed that a spherical cavity having a radius a = 200 nm embedded in a medium (filler material) having a refractive index n = 1.4962 is irradiated with incident electromagnetic waves of intensity I _o . For the visible representation of forward and backward scattered waves, the ratio of scattered wave intensity I _s and incident wave intensity I _o is a wavelength selected from the first and second regions I and II described above. Polar coordinates are shown for each of these. Results for the wavelengths selected from the first region I are shown in FIG. 13, and results for the wavelengths selected from the second region II are shown in FIG. 14. In bipolar coordinates, the spherical cavity is centered and irradiated from the left. The results in FIGS. 13 and 14 show that the wavelengths of the first region I are strongly scattered (ie transmitted) while the wavelengths of the second region II are scattered forward (ie, transmitted). As well as being scattered back (ie, reflected). Accordingly, the first region I of FIG. 12 may be associated with a wavelength range 0 <λ <λ ₄ at 504, and the second region II of FIG. 12 is a wavelength range at 504. λ ₄ <λ ≦ λ _c . Although not explicitly shown in FIG. 12, the ratio of scattered wave intensity I _s and incident wave intensity I _o approaches 1 for sufficiently large wavelengths. The waves in this region correspond to waves with wavelengths satisfying λ> λ _c at 504 in FIG. 10, which are partially transmitted and partially reflected at the same scales. These results confirm that the spherical cavity embedded in the dielectric medium (filler material) acts to reflect infrared electromagnetic waves. In addition, the presence of spherical cavities in a mixture such as paint improves insulation against heat loss by reducing heat transfers associated with the direct heat conduction process.

Although the subcoating layers in the preceding figures contain many spherical cavities, it is evident that ΔQ was calculated in the case of a single spherical cavity, and these results were used to explain the transmission and reflection actions in the subcoating layers. Such analysis is valid if the spherical cavities of the respective subcoating layers are sufficiently separated from each other so that the interaction between them is neglected. For a given wavelength of interest, for example λ, the two nearest neighboring spherical particulates separated by a distance of ˜10λ may be considered 'sufficiently separated'. For example, in an ideal subcoating layer 104 where the transmission and reflection behaviors of waves are described by reference numeral 504, the wavelength of interest, λ, can be represented by λ = λ ₄ , where the reflection region is Define the starting point. Similarly, in an ideal subcoat layer 101 where reference numeral 501 describes the transmission and reflection actions of waves, the wavelength of interest, λ, can be represented by λ = λ ₁ . Now, for the physical subcoating layers (as opposed to ideal subcoating layers), the transmission and reflection actions of the wave are characterized by the ΔQ graph.

Hereinafter, various methods of manufacturing the multilayer coating system will be described. Simple procedures relating to the manufacture of a multilayer coating system are (1) preparing the mixtures for each subcoating layer and (2) applying each mixture onto the substrate to form each subcoating layer.

15 illustrates an exemplary method of making a multilayer coating system. Small spherical cavities of constant size are mixed in the first container containing the first solution. The second container containing the second solution is mixed with large spherical cavities of constant size larger than the small spherical cavities of the first solution. If the spherical cavities are mixed in a conventional paint, the first solution of the first container and the second solution of the second container may be formed of the conventional paint. The first subcoat layer on the substrate can be formed by dipping an uncoated substrate into a first solution of a first container. Subsequently, the substrate to which the first subcoat layer is applied may be dried or cured before dipping into the second solution of the second container. Thereafter, the second subcoat layer is applied onto the first subcoat layer by dipping the substrate on which the first subcoat layer is formed into the second solution of the second container. By drying or curing the substrate to which the second subcoating layer is applied, a multilayer coating system in which two subcoating layers are sequentially formed on the substrate can be manufactured. This dipping method can form a multilayer coating system on both surfaces of a substrate.

For substrates for forming a multilayer coating system on only one surface but not on both surfaces, the multilayer coating system may be applied by applying a mixture of spherical cavities onto one surface of the substrate by repeating spin coating. Can be formed.

For objects having a cylindrical medial side, such as the medial side of a pipe, a mixture of spherical cavities can be applied to the cylindrical medial side by repeated spin casting to form a multilayer coating system.

For objects such as housing surfaces or automobile surfaces, it is possible to form multilayer coating systems on that surface by repeating the spraying method.

In the method of manufacturing the multilayer coating system illustrated by way of example in FIG. 15, the first and second solutions as a mixture for each subcoating layer are formed by mixing conventional paint with spherical cavities, but not limited thereto. Does not. Mixtures for each subcoating layer of the multilayer coating system can be prepared by mixing the spherical cavities together in any solutions. These solutions include solvent base coatings, composite mixtures (such as adhesives, clays, etc.), polyurethanes, elastomers, plastics, gelatin, epoxy but also not limited to polymeric materials such as epoxy, acrylic, polymethylmethacrylate (PMMA), as well as some listed resins and binders such as cement. Does not. As an alternative example, spherical cavities of one size may be mixed in a liquefied PMMA (polymethylmethacrylate) solution. In this case, the second solution in FIG. 15 may also be represented by liquefied PMMA, but spherical cavities of larger diameter sizes are mixed than those mixed in the first solution. The multilayer coating system can be formed on the substrate according to the dipping procedures already described.

In another alternative example, the mixtures for each subcoating layer of a multilayer coating system may be prepared by mixing spherical cavities into a solution formed of a polymeric material such as polyurethane. In this case, the first solution and the second solution of FIG. 15 may be represented as polyurethane solutions, where each solution contains spherical cavities of appropriate diameter sizes.

16 illustrates another method of manufacturing a multilayer coating system, by way of example. Such a multilayer coating system can be formed thereon by soaking (or dipping) a fabric net into a first solution and a second solution according to the processes described previously. First, prepare a fabric network as shown in FIG. 16A. A woven net is a kind of net made of thread or wire. Then, as shown in FIG. 16B, one subcoating layer is formed by dipping and coating the fabric net into a first container containing a first solution in which spherical cavities are mixed. In this case, since the fabric network serves as a skeleton, the sub-coating layer is not easily broken or broken, as well as the structure is flexible. In this way a plurality of sub-coating layers are formed. The plurality of sub-coating layers thus formed may be stacked to form a multilayer coating system. In this case, in order to bond the plurality of laminated sub-coating layers, the sub-coating layers may be bonded with a material such as an adhesive or sewn with a thread. An example of such a multilayer coating system completed is shown in FIG. 16C.

Similarly, a multilayer coating system can be formed on strands of textile fibers. That is, the fabric fiber strands may be formed thereon by soaking (or dipping) the fabric fiber strands into the first and second solutions according to the processes described previously. Threads of such fiber strands coated with a multilayer coating system can be used to make heat resistant clothes. Such multilayer coating systems may also be utilized as insulation in shoes.

17 illustrates another method of manufacturing a multilayer coating system by way of example. Prepare a first solution in a first container. The first solution refers to a material in which a solution and a small cavity are mixed. This first solution can be poured into a mold and then cured to make each subcoating layer of the multilayer coating system. For example, the first solution in the first container may be poured into a mold and dried to form a first subcoat layer. The second solution in the second container can be poured into another mold and dried to form a second subcoating layer. The first subcoating layer and the second subcoating layer thus formed may be pasted with an adhesive to form a multilayer coating system. In addition to attaching the first subcoat layer and the second subcoat layer with an adhesive, there is also a method of sewing two layers.

The first and second solutions of FIG. 17 may be made by mixing variously, and one of them is a method of mixing spherical cavities in an aqueous polyurethane or water based polyurethane. The water-soluble polyurethane has a structure in which a solid polyurethane polymer is emulsified in water, and there is a difference in specific gravity between water and a solid polyurethane polymer depending on the product. When water-soluble polyurethanes having a specific gravity of 40% solid polyurethane polymer and 60% water are used, the co-particles can contain at least twice the mass of the solid polyurethane polymer. The higher the specific gravity of the cavity, the higher the viscosity of the solution. On the other hand, if the specific gravity of the cavity is too small, the viscosity of the solution is low workability is good, but there is a disadvantage that the heat insulation is poor. As an example, when using a cavity as a K1 glass bubble sold by 3M, the solid polyurethane polymer mass can be up to 40 grams and the K1 glass bubble mass can be up to 20 grams. As another example, 3M's S60HS glass bubble can be used to weigh 40 grams of solid polyurethane polymer and up to 88 grams of S60HS glass bubble mass. As the amount of glass bubble is added, the viscosity of the solution becomes too high to reach the state of no flow. In order to increase the thermal insulation, glass bubbles should be added as much as possible, but it is necessary to compromise the viscosity of the working solution.

The foregoing is an example of one of various exemplary embodiments and is not to be construed as limited thereto. Those skilled in the art can appreciate that many modifications are possible in the exemplary embodiments without departing from new teachings or advantages. All such modifications are intended to be included within the scope of this disclosure as defined in the claims.

The present invention can be used in the field to which the heat shield system and its manufacturing method are applied.

Claims (25)

1. A layer 1 comprising a plurality of spherical cavities having a radius a ₁ which are irregularly distributed and separated from each other and a filler material of refractive index n ₁ interposed in the space between the spherical cavities; And

   The next layers represented by the next word equation,

   "Layer i comprising a plurality of spherical cavities of radius a _i located on layer i-1 and irregularly distributed and separated from each other, and a filler material of refractive index n _i interposed in the spaces between the spherical cavities ( Where i is an integer greater than 1) "

   Multilayer coating system having a.
2. The method according to claim 1,

   A multilayer coating system further comprising a substrate under said layer 1.
3. The method according to claim 1,

   And a substrate further provided on said layer located furthest from said layer 1.
4. The method according to claim 2 or 3,

   Wherein said substrate comprises one selected from the group consisting of a conductive material, a dielectric material, a semiconductor material, and a fabric.
5. The method according to any one of claims 1 to 3,

   And a sealing member for sealing the multilayer coating system from the outside.
6. The method according to claim 5,

   A multilayer coating system substantially free of air inside the sealing member.
7. The method according to claim 1,

   Said layer i having a thickness different from said layer i-1, where i is an integer greater than one.
8. The method according to claim 1,

   Said layer i having the same thickness as said layer i-1, where i is an integer greater than one.
9. The method according to claim 1,

   Wherein each layer has a thickness in the range of 0.01 microns to 10,000 microns.
10. The method according to claim 1,

    And the filler material comprises one selected from the group consisting of polymeric materials, binders, resins, dielectric materials, and ceramic materials.
11. The method according to claim 1,

    And the refractive index of the filler material satisfies n _i = n _i-1 where i is an integer greater than one.
12. The method according to claim 1,

    And the refractive index of the filler material satisfies n _i > n _i-1 , where i is an integer greater than one.
13. The method according to claim 1,

    Wherein the radius of the spherical cavities satisfies a _i > a _i-1 , where i is an integer greater than one.
14. The method according to claim 1,

    The radius of the spherical cavities and the refractive index of the filler material satisfy a _i = a _i-1 and n _i > n _i-1 , where i is an integer greater than one.
15. The method according to claim 1,

    And further comprising a plurality of spherical cavities of radius b which are irregularly distributed and separated from each other in all the layers, b being b> a ₁ and b > A multilayer coating system that meets a _i , where i is an integer greater than one.
16. The method according to claim 15,

    Further comprising a plurality of spherical particles of a radius c ₁ irregularly distributed and separated from each other in the filler material constituting the layer 1,

    Further comprising a plurality of spherical particles of a radius c _i irregularly distributed and separated from each other in the filler material constituting the layer i,

    C ₁ satisfies b> a ₁ > c ₁ ,

    Wherein c _i is b> a _i> c _i and c _i> c _i-1 (where i is an integer greater than 1) multi-layer coating systems to meet.
17. The method according to claim 16,

    Wherein the spherical particles comprise one selected from the group consisting of conductive materials, dielectric materials, semiconductor materials, and ceramic materials.
18. The method according to claim 1,

    The filler material further comprises a plurality of holes therein.
19. The method according to claim 18,

    Wherein the plurality of holes are a plurality of spherical holes having a larger size radius than the spherical cavities.
20. The method according to claim 1,

    Wherein the spherical cavity has a cavity radius in the range of 0.002 microns to 500 microns.
21. The method according to claim 1,

    Wherein the spherical cavity is formed of one selected from the group consisting of a hollow dielectric shell, a hollow conductor shell and a hollow semiconductor shell.
22. The method according to claim 1,

    A first electrode located adjacent one of the two faces of the layer farthest from the substrate;

    A second electrode located between the layer 1 and the substrate;

    A first voltage applied to the first electrode; And

    And a second voltage different from the first voltage and applied to the second electrode.
23. (1) preparing a first solution in which a plurality of spherical cavities of radius a ₁ are mixed with a filler material of refractive index n ₁ ;

    (2) By treating the substrate with the first solution, a filler having a refractive index n ₁ interposed in the space between the plurality of spherical cavities having a radius a ₁ and the spherical cavities that are irregularly distributed and separated from each other on the substrate. Forming a layer 1 comprising the material;

    (3) preparing an i solution (where i is an integer greater than 1), wherein a plurality of spherical cavities of radius a _i are mixed with a filler material of refractive index n _i ; And

    (4) between the spherical cavities and the plurality of spherical cavities having a radius a _i , which are irregularly distributed and separated from each other, on the layer i-1 by treating the substrate on which the layer i-1 is formed in the i-th solution; Forming a layer i comprising a filler material of refractive index n _i interposed in the space of i, where i is an integer greater than one

    Method of manufacturing a multilayer coating system comprising a.
24. The method according to claim 23,

    The treatment of step (2) may include: dipping the substrate into the first solution, spin coating the first solution into the substrate, and spin the first solution into the substrate. A method of manufacturing a multilayer coating system, the method selected from the group consisting of a casting method and a method of spraying the first solution onto the substrate.
25. The method according to claim 23,

    The treatment of step (4) includes a method of dipping a substrate on which the layer i-1 is formed in the i-th solution, and spin coating the i-th solution on the substrate on which the layer i-1 is formed. ), A method of spin casting the i-th solution onto a substrate on which the layer i-1 is formed, and a method of spraying the i-th solution on a substrate on which the layer i-1 (where i is an integer greater than 1) is formed. Method for producing a multilayer coating system which is one selected from the group consisting of a spraying method.

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