Transparent solar control laminated glass for windows

Abstract

Provided is a transparent solar control laminated glass for windows having excellent solar control performance, which effectively blocks sunlight in summer, effectively brings sunlight into a room in winter, and can significantly reduce heating and cooling load. The laminated glass comprises a 0.1 mm to 5 mm thick solar control interlayer of 0.1 mass% to 4.5 mass%, relative to the total solids fraction of the thermoplastic resin, of aerogels with a silica shell, the internal space of which is partitioned into a range of 5 nm to 100 nm and the mean value of the average distances of the long, intermediate, and short axes of which is 0.2 to 16.8 μm, dispersed in a transparent thermoplastic resin which transmits solar light sandwiched between two glass plates.

Description

Transparent solar radiation control laminated glass for windows

[0001] The present invention relates to transparent solar radiation control laminated glass for windows. More specifically, the present invention relates to an intermediate film for transparent solar radiation control laminated glass that is transparent and highly visible, which can block sunlight in summer when the sun altitude is high and admit sunlight in winter when the sun altitude is low, and to transparent solar radiation control laminated glass for windows using the intermediate film for laminated glass.

[0002] Laminated glass having excellent performance such as impact resistance, penetration resistance, and crime prevention by sandwiching an intermediate film between a pair of glass plates is widely used in openings of buildings, automobiles, etc. In these fields, from the perspective of current environmental and energy-saving measures, high heat insulation is required to reduce the cooling load caused by solar radiation.

[0003] Generally, as a method of reducing the cooling load caused by solar radiation, there are heat ray reflective glass coated with a metal thin film that blocks sunlight incident from window glass and heat ray absorbing glass that absorbs heat rays. However, these glasses have poor visibility and block solar radiation even in winter, which increases the heating load.

[0004] As for heat insulation laminated glass, for example, in Patent Document 1, a heat ray shielding intermediate film for laminated glass in which metal oxide particles such as tin-doped indium oxide particles (ITO) are dispersed in a thermoplastic resin is produced, and the produced intermediate film for laminated glass is sandwiched and adhered between two glass plates to disclose solar radiation shielding laminated glass.

[0005] Patent Document 2 discloses an intermediate film for laminated glass and laminated glass in which a heat ray shielding layer containing a heat ray shielding agent such as an aerogel layer for improving heat insulation and tin-doped indium oxide (ITO) particles, antimony-doped tin oxide (ATO) particles, aluminum-doped zinc oxide (AZO) particles, indium-doped zinc oxide (IZO) particles, tin-doped zinc oxide particles, etc. for improving heat ray shielding property is laminated.

[0006] Patent Document 3 discloses laminated glass in which a functional plastic film having an infrared reflective layer and an infrared absorbing layer is sandwiched between two glass plates with a thermoplastic resin adhesive. Patent Document 4 discloses near-infrared reflective laminated glass in which an interlayer film of a near-infrared reflective film made of a dielectric multilayer film is formed on a polymer resin sheet, and the near-infrared reflective film is laminated between two glass plates. As such, there are many types of laminated glass that block solar radiation by providing infrared reflective layers and infrared absorbing layers, but these solar-shielding laminated glasses have many problems with visibility and also block solar radiation in winter, which increases the heating load.

[0007] Furthermore, as described in Patent Document 5, in laminated glass in which an infrared reflective film containing an infrared absorbing substance is sandwiched between two glass plates in an optical interference film in which high refractive index layers and low refractive index layers made of organic material are alternately laminated, the difference in refractive index between the high refractive index layer and the low refractive index layer is small, making it necessary to perform alternating lamination of hundreds of layers or more, which makes it difficult to achieve high productivity and has the disadvantage that the layers are easily delaminated when bent or folded.

[0008] Thus, window glass in buildings and automobiles is a major factor in determining the heating and cooling load, and if laminated window glass that can control the entry and exit of light and heat can be realized, the heating and cooling load can be greatly reduced.

[0009] Therefore, as a new heat shielding method, a transparent window member made of a plate-shaped or sheet-shaped plastic material having a pair of parallel planes has multiple air layers made of planar slits of a certain thickness formed vertically at regular intervals and inclined with respect to the plane. At the interface between the transparent window member on the outside and the air layer, sunlight incident from above at an angle greater than a predetermined angle from the outside is totally reflected, blocking its intrusion into the room. Patent document 6 discloses a light-adjustable transparent window in which the outside can be seen almost completely from the inside, blocking summer sunlight and letting in winter sunlight.

[0010] However, these methods result in the lower section being considerably thicker than the upper section in order to create a downward-sloping surface. While this could be used as a window component, sandwiching this component between two panes of glass would further increase the thickness and alter the total reflection angle, making it difficult to use as laminated window glass. Additionally, increasing the number of slopes reduces the thickness of the lower section, but it becomes more difficult to create an even more precise slope, leading to increased manufacturing costs. Furthermore, this method exhibits a significant shading effect on south-facing windows during the day when the sun is high in the sky, but the shading effect diminishes in the morning and evening when the sun is low in the sky and sunlight enters from a lower position.

[0011] Therefore, the inventors have developed a transparent solar radiation control film for windows that uses a material that is transparent in the visible light band and the near-infrared band to adjust the amount of solar radiation blocked depending on the angle of sunlight. It allows good transmission from eye level up, down, left, and right, i.e., up to about 30° from the line of sight, and blocks incident sunlight at angles greater than that. It is transparent and highly visible, effectively blocks summer sunlight, effectively lets winter sunlight into the room, and reduces heating and cooling loads, thus possessing excellent solar radiation control performance. (Patent pending)

[0012] Japanese Patent Publication No. 6374914 WO2018 / 155551 Japanese Unexamined Patent Publication No. 2010-222233 Japanese Unexamined Patent Publication No. 2007-148330 Japanese Patent Publication No. 4848872 Japanese Patent Publication No. 5493150

[0013] However, because this transparent solar light-blocking film for windows is applied to window glass afterwards, it needs to be made of a flexible yet rigid material and have a total thickness of only a few tens of micrometers to make it easy to apply. Therefore, it is difficult to incorporate large amounts of hollow microparticles such as aerogel into the adhesive or coating agent, which naturally limits the solar shading effect. In addition, it is directly exposed to air and comes into contact with people's hands, so there were also durability issues.

[0014] Generally, when using materials such as metals or ceramics with high reflectivity or absorptivity to block sunlight by reflection or absorption, they will also reflect or absorb visible light in the same way. Therefore, if you use metals or ceramics with high reflectivity or absorptivity to increase the level of shielding, they will reflect or absorb visible light as well, impairing the function of the window glass.

[0015] Therefore, selectively blocking only near-infrared light would not impair the transparency or transmittance of visible light, but achieving this is extremely difficult with current technology. Furthermore, the human field of vision consists of a discriminative field of vision (within approximately 5°) for visual acuity and color discrimination, an effective field of vision (within approximately 30° horizontally and 20° vertically) for instantaneous reception through eye movements alone, and a central field of vision that processes high-density information, including the central cavity. If the transparency and transmittance of this range are not impaired, visibility will hardly be affected.

[0016] Therefore, the inventors have developed a transparent solar light-controlling laminated glass for windows that uses a material that is transparent in the visible light band and the near-infrared band to adjust the amount of solar radiation blocked depending on the angle of sunlight. It allows good transmission from eye level up, down, left, and right, i.e., up to about 30° from the line of sight, and blocks incident sunlight at angles greater than that. It is transparent and highly visible, effectively blocks summer sunlight, effectively lets winter sunlight into the room, and significantly reduces the heating and cooling load.

[0017] The transparent solar light-controlling laminated glass for windows of the present invention is characterized in that a solar light-controlling interlayer, with a thickness of 0.1 mm to 5 mm, is sandwiched between two glass plates. This interlayer consists of a silica shell aerogel, whose internal space is divided into a range of 5 nm to 100 nm and whose average distance between the long axis, medium axis, and short axis is 0.2 to 16.8 μm, dispersed in an amount of 0.1% to 4.5% by mass relative to the total solid content of the thermoplastic resin.

[0018] Furthermore, in the reflection of transparent materials, methods are known that utilize the reflective properties of the material, i.e., specular reflection, to reflect solar radiation, and methods that utilize total internal reflection caused by the difference in refractive index at the interface of the transparent material, as described in reference 5 above.

[0019] Total internal reflection occurs when light enters a medium with a lower refractive index from a medium with a higher refractive index, and if the angle of incidence is greater than or equal to the critical angle, the light cannot pass through the interface and total internal reflection takes place.

[0020] Normally, sunlight passes through the outside air, then passes through and reflects off a glass plate before entering a room. Assuming a transparent glass plate with a light transmittance of approximately 90%, the refractive index of a transparent glass plate is generally about 1.5, so Snell's Law can be expressed as follows: Incidence from outside air to glass plate: n1Sinθ1 = n2Sinθ2 Ingress and egress from glass plate to room: n2Sinθ2 = n1Sinθ1 Medium 1 (air): Refractive index n1: 1.0 Medium 2 (glass plate): Refractive index n2: 1.5 When sunlight enters a glass plate at 60°, it travels through the glass at 35.3° due to refraction and exits into the room at 60°. In other words, when the sun's altitude is 60°, sunlight passes through the glass plate and enters the room at 60°.

[0021] The critical angle when sunlight enters the room from a glass plate is given by sinθm = n1 / n2 = 1 / 1.5, which is 41.8°. The critical angle is the phenomenon that occurs when the exit angle is 90 degrees. Therefore, normally, sunlight enters the room at a 60° angle and exits the glass plate with a refractive index of 1.5 at an angle of 35.3°, so total internal reflection does not occur.

[0022] In reference 5, to achieve total internal reflection, the interior side of the acrylic partition is tilted downwards to the right, and X° is designed so that 35.3° + X° ≥ 41.8°.

[0023] However, the inventors have developed a transparent solar light-regulating laminated glass interlayer for windows that has non-directional solar light-regulating performance in its solar shading effect, by employing a method of reflection occurring in a transparent material, that is, reflection according to Fresnel's equation, which is different from the method described above, and a transparent solar light-regulating laminated glass for windows in which the interlayer for laminated glass is sandwiched between two glass plates.

[0024] This is a cross-sectional view of a transparent solar light-regulating laminated glass for windows according to one preferred embodiment of the present invention. This is a schematic diagram of sunlight passing through the silica shell aerogel. This is a schematic diagram of sunlight passing through the transparent solar light-regulating laminated glass for windows according to the present invention. This is a schematic diagram relating the angle of incidence of sunlight and the number of times it collides with the silica shell aerogel.

[0025] According to Fresnel's equation, when light enters an interface between materials with different refractive indices, some is reflected and some is transmitted. The speed at which light travels varies depending on the type of medium. When a wave travels from one medium to another, the change in speed also changes its direction of travel. This change in direction at an interface is called refraction. The refractive index is the value obtained by dividing the speed of light in a vacuum by the speed of light in a material. Light refracts between two media, and the numerical value that indicates the ratio of the degree of refraction is called the refractive index. It is expressed as a ratio to the vacuum when light is incident on a medium from a vacuum. Furthermore, even in the same material, the refractive index differs depending on the wavelength. This property is called dispersion.

[0026] Next, we present Fresnel's formula: R = [(n1 - n2) / (n1 + n2)] ２ R: Reflectance n1: Refractive index of medium 1 n2: Refractive index of medium 2 I = I ０ [1-(n1-n2) / (n1+n2)] ２ I ０ : Intensity of incident light I: Intensity of outgoing light

[0027] As is clear from the above, the greater the difference between the refractive index n1 of medium 1 and the refractive index n2 of medium 2, the greater the reflectance and the less light is transmitted. For example, it is well known that when sunlight passes through the outside air and then through a 3 mm thick glass plate and enters a room, about 4% is reflected at the surface of the glass plate with a refractive index of about 1.5, and about 3.8% is reflected when it exits the glass plate into the air, for a total of 7.8%, resulting in a transmittance of about 90%. The refractive index of air is 1.000292 at 0°C and 1 atmosphere. This is almost the same as a vacuum. Therefore, from Fresnel's equation, it can be seen that in order to increase the reflectance, a material with a refractive index greater than that of air should be used.

[0028] Furthermore, the following equation shows that in order to increase the reflectance and decrease the transmittance according to Fresnel's equation, one can stack multiple layers of air and medium. For example, when four layers are stacked, I = I ０ [1-{(n1-n2) / (n1+n2)} ２ ] ４ For example, aerogel with a hollow silica shell has a structure in which air is surrounded by a silica shell. And its cross-section is in the order of silica shell, air, silica shell.

[0029] In particular, porous aerogels, which have a network structure in which nano-order fine silica particles are connected, have an internal space divided into areas ranging from 5 nm to 100 nm, so they repeatedly reflect and transmit light. In other words, they are ideal materials for increasing reflectivity according to Fresnel's equation.

[0030] Generally, when light is incident on a transparent substance containing dispersed microparticles, if the wavelength of the light is shorter than the size of the microparticles, it is blocked by the microparticles. However, if the wavelength is longer than the microparticles, it passes through the material due to diffraction. As the microparticles become even smaller, scattering occurs. The scattering intensity is proportional to the sixth power of the particle diameter and inversely proportional to the fourth power of the wavelength of the incident light, so the larger the particle diameter, the greater the scattering intensity. For example, in an ultraviolet-blocking agent containing dispersed microparticles, when light is irradiated, highly directional ultraviolet rays collide with the microparticles and are blocked, but the less directional visible light bends around the microparticles due to diffraction, making it appear transparent. However, if the particle diameter of these microparticles becomes larger than that of the visible light, even if the light bends slightly, it cannot bend around the larger microparticles, and thus, like ultraviolet rays, even visible light is blocked. A similar phenomenon, diffraction, occurs with all waves, including sound waves, water waves, and electromagnetic waves (such as visible light and X-rays). This shows that to block sunlight, one can use particles larger than the wavelength of sunlight.

[0031] Normally, objects like metals absorb some of the radiant heat and reflect the rest, so the following relationship holds between the absorptivity α and reflectivity ρ: "α + ρ = 1," indicating that they do not transmit visible light or infrared radiation. However, objects like glass and plastics are gray materials that partially absorb, partially reflect, and partially transmit radiant heat. In the case of such gray materials, the following relationship holds between the absorptivity α, reflectivity ρ, and transmittance τ: "α + ρ + τ = 1," indicating that they transmit visible light and infrared radiation. Furthermore, according to the Lambert-Beer law below, reducing the thickness of the shell increases the transmittance. Absorbance A = -logT = εCL (A: absorbance, T: transmittance, ε: extinction coefficient, which is a value specific to the material, C: molar concentration of the material in the cell solution, L: cell length (length in the direction of irradiation))

[0032] Therefore, by using transparent hollow microparticles with a very thin shell instead of solid microparticles that have high reflectivity and absorption, in addition to reflection at the surface of the hollow microparticles, sunlight that penetrates the shell and enters the interior of the hollow microparticles is also reflected due to the difference in refractive index between the shell and the internal air layer. Thus, a transparent material with a large shielding effect against sunlight can be obtained. In particular, porous aerogels with an internal space divided into areas ranging from 5 nm to 100 nm can achieve a large shielding effect because they repeatedly reflect and transmit light.

[0033] Furthermore, regarding the visibility of solar-controlled laminated glass, the thickness of the transparent solar-controlled interlayer is thin, and the distance the light travels is short, so the proportion of light that collides with the aerogel dispersed almost uniformly inside is small, resulting in a small decrease in visible light transmittance. Therefore, the transparency and transmittance are not compromised, and the visibility is almost the same as that of ordinary glass.

[0034] Furthermore, during the winter months (from the autumnal equinox to the vernal equinox), the sun's altitude is low, and the angle of incidence on the south-facing glass surface is approximately within 45°. Therefore, light transmitted through the adhesive layer, in which aerogel is dispersed almost uniformly, at an angle of approximately 45° perpendicular to the surface, travels a similarly short distance, resulting in fewer collisions with the aerogel. This reduces the solar radiation shading effect, allowing more sunlight to enter the room.

[0035] In contrast, during the summer (from the vernal equinox to the autumnal equinox), the sun's altitude is high, almost always above 60°, which increases the distance light travels through the transparent solar radiation-modulating interlayer, in which aerogel is dispersed almost uniformly. As a result, the proportion of light that collides with the almost uniformly dispersed aerogel inside increases, and the shielding effect also increases.

[0036] Furthermore, in Tokyo, located at 139.74° East longitude and 35.65° Latitude, the profile angle from June to August, calculated from the solar altitude and solar azimuth angle, is 70° or greater.

[0037] Therefore, in the summer months from June to August when the sun is high in the sky, the transparent solar radiation-controlled laminated glass of the present invention exhibits a greater solar radiation shielding effect because the distance light passes through the transparent solar radiation-controlled interlayer increases not only vertically due to the sun's altitude but also horizontally, and the proportion of light that collides with the aerogel also increases. In other words, a solar radiation shielding effect can be obtained even during the early morning and evening hours of summer when the sun is low in the sky.

[0038] Therefore, it can block a lot of sunlight during the warm or hot months from April to September, and allow a lot of sunlight to pass through during the cool or cold months from October to March. By applying such transparent solar-controlling laminated glass to window panes, it is possible to obtain transparent, highly visible, solar-controlling laminated glass for windows that automatically blocks sunlight in the summer and lets in sunlight in the winter.

[0039] Hereinafter, preferred embodiments of the transparent solar light-regulating laminated glass for windows of the present invention will be described with reference to the accompanying drawings. However, the transparent solar light-regulating laminated glass for windows of the present invention is not limited in any way to these embodiments.

[0040] Figure 1 shows a cross-sectional view of a transparent solar light-regulating laminated glass for windows according to one preferred embodiment of the present invention. The transparent solar light-regulating laminated glass for windows 10 is a transparent solar light-regulating laminated glass in which a transparent solar light-regulating interlayer, in which silica shell aerogel 2 is dispersed in a thermoplastic resin 1, is sandwiched between two glass plates 3, and this can be installed directly into a window frame.

[0041] Figure 2 shows a schematic diagram of sunlight passing through the silica-shell aerogel, and Figure 3 shows a schematic diagram of sunlight passing through the window transparent solar control laminated glass of the present invention. First, sunlight is irradiated from the sun toward the window glass. The glass plate 3 and the thermoplastic resin 1 of the transparent solar control intermediate film transmit a large amount of sunlight (wavelength 0.3 μm to 3.0 μm). The sunlight passing through the glass surface also passes through the thermoplastic resin 1 of the transparent solar control intermediate film and reaches the outer surface of the partition wall 31 of the silica-shell aerogel. The sunlight that passes through the thermoplastic resin 1 of the transparent solar control intermediate film and reaches the silica-shell aerogel 2 is partially reflected due to the difference in refractive index at the interface between the outer surface of the partition wall 31 of the aerogel and the thermoplastic resin 1 of the transparent solar control intermediate film, and the rest passes through. The sunlight passing through the silica shell reaches the air layer inside the silica-shell aerogel 2. The sunlight incident on the air layer inside the silica-shell aerogel 2 is partially reflected due to the difference in refractive index at the interface between the inner surface of the partition wall 31 of the silica-shell aerogel and the inner air layer, and the rest passes through. The sunlight passing through the inner air layer reaches the inner surface of the partition wall 31 of the silica-shell aerogel. Part of it is reflected due to the difference in refractive index at the interface between the inner air layer and the inner surface of the partition wall 31 of the silica-shell aerogel, and the rest passes through. The sunlight passing through the partition wall 31 of the silica-shell aerogel reaches the outer surface of the partition wall 31 of the silica-shell aerogel. The sunlight that passes through the silica-shell aerogel and reaches the thermoplastic resin 1 of the transparent solar control intermediate film is partially reflected due to the difference in refractive index at the interface with the thermoplastic resin 1 of the transparent solar control intermediate film at the outer surface of the partition wall 31 of the silica-shell aerogel, and the rest passes through.

[0042] Figure 4 shows a schematic diagram regarding the incident angle of sunlight and the number of collisions with the silica-shell aerogel. In the figure, the incident angle is indicated by θ. It can be seen that the larger the incident angle of sunlight, the more times the silica-shell aerogel 2 is collided with, and the greater the shielding effect.

[0043] Thus, it is considered that part of the sunlight that has repeated reflection and transmission is reflected and emitted to the outside air, or part of it is absorbed by the thermoplastic resin 1 of the transparent solar dimming intermediate film and then emitted to the interior or the outside air. Further, an aerogel of a porous silica shell with an internal space partitioned in the range of 5 nm to 100 nm has a structure in which hollow internal spaces continuously exist, and the reflection and transmission at the interface between the internal air layer and the inner surface of the partition wall 31 of the silica shell aerogel due to the large difference in refractive index between the air layer and the silica shell, and the reflection and transmission at the interface between the internal air layer and the inner surface of the partition wall 31 of the silica shell aerogel can occur continuously.

[0044] Next, the solar transmittance according to the incident angle will be described. According to Lambert-Beer's law, it can be seen that the transmittance decreases as the thickness of the layer increases. The thickness of the layer, that is, the transmission distance of the sunlight, can be expressed by the following formula. X = 1 / cosθ X = transmission distance of sunlight 1 = thickness of the layer θ = incident angle

[0045] Conventional hollow particles such as silica shells are dispersing an aerogel of a silica shell with a very low density of only the silica shell excluding micropores into a resin to produce heat-insulating laminated glass based on the finding that it is necessary to reduce the bulk density of the silica shell to obtain an extremely low thermal conductivity. For example, as an example of heat-insulating laminated glass coated with hollow particles having a low thermal conductivity, there is the heat-insulating laminated glass described in Patent Document 2. However, no matter how much the thermal conductivity is reduced, it is difficult to obtain a solar radiation shielding effect. Therefore, when heat ray shielding properties are required, the resin layer contains heat ray absorbers such as tin-doped indium oxide (ITO) particles, antimony-doped tin oxide (ATO) particles, and aluminum-doped zinc oxide (AZO) particles to shield heat rays.

[0046] The wavelength of solar radiation, or sunlight, is 0.3 μm to 3.0 μm. By reflecting or absorbing wavelengths in this range, a solar radiation shielding effect can be obtained even with a thinner solar radiation-modulating interlayer. Therefore, it is preferable to make the silica shell larger than the wavelength of sunlight (0.3 μm to 3.0 μm). By making the silica shell larger than the wavelength of sunlight (0.3 μm to 3.0 μm), better reflection can be achieved from the surface and interface of the aerogel in the silica shell.

[0047] In order to obtain a solar radiation regulating effect through reflection, it is preferable to use a silica shell aerogel in which the internal space is partitioned substantially uniformly and the wavelength of sunlight is slightly larger than 0.3 μm to 3.0 μm.

[0048] The silica shell aerogel of the present invention is obtained by grinding the manufactured product into a powder, and it has a complex shape, being an ellipsoid with major, medium, and minor axes, all of which are at different distances. Therefore, when the thermoplastic resin interlayer containing dispersed silica shell aerogel of the present invention is processed into a sheet, the dispersed aerogel tends to tilt within the resin layer, with the minor axis perpendicular to the sheet substrate of the interlayer, and the medium and major axes becoming horizontal. In other words, the surface area exposed to sunlight becomes larger, and more sunlight can be reflected. Therefore, the distances of the major, medium, and minor axes of a single aerogel are measured, and the average value calculated from these is expressed as the "average distance of the major, medium, and minor axes," and is used as an indicator of the size of the aerogel. The "average value of the average distances of the long axis, medium axis, and short axis of the silica shell aerogel" shown below refers to the average value of the "average distances of the long axis, medium axis, and short axis of the silica shell aerogel" obtained in this manner. Specifically, it refers to the average value calculated from the average distances of the long axis, medium axis, and short axis of aerogels randomly selected from images taken with a microscope (KEYENCE Corporation: Model No. VHX-2000). The average value of the average distances of the long axis, medium axis, and short axis of the aerogel is preferably 0.2 μm to 16.8 μm, more preferably 0.3 μm to 10 μm, and most preferably 0.3 μm to 5 μm. If the average value of the average distances of the long axis, medium axis, and short axis of the aerogel is 3 μm or more, the solar light control effect of the present invention can be obtained, and if it is 10 μm or less, high visibility and transparency can be maintained.

[0049] Furthermore, it is preferable to use a silica shell aerogel in which the average distance of the long axis, medium axis, and short axis is within a certain range. If the average distance of the long axis, medium axis, and short axis of the silica shell aerogel of the present invention is in the range of 0.2 μm to 16.8 μm, the wavelength of sunlight can be effectively blocked, and it is also easier to disperse it in the sheet layer of the solar radiation regulating interlayer, which allows the thickness of the solar radiation regulating interlayer to be reduced. Note that the above-mentioned "range of the average distance of the long axis, medium axis, and short axis of the silica shell aerogel" refers to the range of average distances that are effective in blocking sunlight.

[0050] <Interlayer Substrate> The transparent solar light-regulating interlayer used in the transparent solar light-regulating laminated glass for windows of the present invention is not particularly limited as long as it can transmit visible and near-infrared rays and provide the strength necessary for shatterproof and penetration-resistant effects. The material constituting the transparent solar light-regulating interlayer is not particularly limited, but polyvinyl butyral (PVB), ethylene vinyl acetate (EVA), and Sentryglass Plus (SGP) are suitable in terms of versatility, visibility, and transparency.

[0051] The thickness of the transparent solar light-regulating interlayer is not particularly limited, as long as it is a thickness that ensures sufficient strength for the transparent solar light-regulating laminated glass for windows, but it is preferably 0.1 to 10.0 mm, and more preferably 0.1 to 5.0 mm. If the thickness of the substrate interlayer is 0.1 mm or more, the transparent solar light-regulating laminated glass for windows can be made to have sufficient strength, and if it is 10.0 mm or less, high visibility and transparency can be maintained, and it can be easily installed in windows.

[0052] Furthermore, the transparent solar light-regulating interlayer may consist of one or more layers, and may also have a transparent near-infrared shielding layer.

[0053] <Solar Radiation Control Interlayer> The solar radiation control interlayer used in the transparent solar radiation control laminated glass for windows of the present invention is made by sandwiching a transparent solar radiation control interlayer, which is made by dispersing silica shell aerogel in a transparent thermoplastic resin, between two transparent glass plates. The solar radiation control interlayer may be a single layer, but may also be multi-layered if necessary. The thickness of the solar radiation control interlayer was measured using a constant-pressure thickness measuring instrument (manufactured by Teclock Co., Ltd., model number: PG-02A, minimum display unit (mm) 0.001).

[0054] The thickness of the solar radiation-controlled interlayer of the present invention is preferably 0.1 to 10.0 mm, more preferably 0.1 to 5.0 mm, and most preferably 0.1 to 3.0 mm. If the thickness of the solar radiation-controlled interlayer is 0.1 mm or more, adhesion strength to glass, shatterproof effect, and penetration-resistant effect are ensured while maintaining the solar radiation-controlled effect of the present invention, and if it is 10 mm or less, high visibility and transparency can be maintained.

[0055] The solar radiation regulating interlayer of the present invention contains 0.1% by mass or more of silica shell aerogel relative to the total amount of solids excluding the silica shell aerogel. The solar radiation regulating effect of the present invention can be obtained by including 0.1% by mass or more of silica shell aerogel relative to the total amount of solids excluding the silica shell aerogel in the solar radiation regulating interlayer. Furthermore, it is preferable that the silica shell aerogel be included in an amount of 0.1% by mass to 4.5% by mass relative to the total amount of solids excluding the silica shell aerogel in the solar radiation regulating interlayer. If the silica shell aerogel content is 4.5% by mass or less relative to the total amount of solids excluding the silica shell aerogel in the solar radiation regulating interlayer, high visibility and transparency can be maintained.

[0056] <Transparent Solar Light-Controlling Interlayer and Thermoplastic Resin> The thermoplastic resin used to form the transparent solar light-controlling interlayer used in the transparent solar light-controlling laminated glass for windows of the present invention is not particularly limited in type as long as it transmits sunlight and is transparent, and can be used as long as it can adhere the transparent solar light-controlling interlayer for windows to the glass surface, and any of the following can be used, such as polyvinyl butyral (PVB), ethylene vinyl acetate (EVA), and Sentryglass Plus (SGP).

[0057] The thermoplastic resin for the interlayer may be used alone or in combination of two or more types. In addition, other components such as tackifiers, ultraviolet absorbers, infrared shielding agents, plasticizers, photopolymerizable compounds, photoinitiators, foaming agents, polymerization inhibitors, antioxidants, fillers, coupling agents, and antistatic agents may be added, to the extent that the objective of the present invention is not impaired.

[0058] As described above, the thickness of the transparent solar light-regulating interlayer is preferably 0.1 to 10 mm, more preferably 0.1 to 5.0 mm. If the thickness of the transparent solar light-regulating interlayer is 0.1 mm or more, adhesion strength to glass, shatterproof effect, and penetration-resistant effect are ensured while maintaining the solar light-regulating effect of the present invention, and if it is 10 mm or less, high visibility and transparency can be maintained.

[0059] As described above, the transparent solar light-regulating interlayer contains 0.1% by mass or more of silica shell aerogel relative to the total amount of solids excluding the silica shell aerogel. The solar light-regulating effect of the present invention can be obtained by including 0.1% by mass or more of silica shell aerogel relative to the total amount of solids excluding the silica shell aerogel in the transparent interlayer. Furthermore, it is preferable that the silica shell aerogel be included in 0.1% by mass to 4.5% by mass relative to the total amount of solids excluding the silica shell aerogel in the transparent solar light-regulating interlayer. If the silica shell aerogel content is 4.5% by mass or less relative to the total amount of solids excluding the silica shell aerogel in the transparent solar light-regulating interlayer, high visibility and transparency can be maintained.

[0060] (Example 1) A silica shell aerogel "MT1100" manufactured by Cabot Specialty Chemicals, Inc. was dispersed in ethylene vinyl acetate (EVA) "UltraSen 751R" manufactured by Tosoh Corporation at concentrations of 0.1% by mass, 1.0% by mass, 2.0% by mass, 3.0% by mass, 4.5% by mass, and 6.0% by mass relative to the solid content. The silica shell aerogel "MT1100" is made of silica with a refractive index of approximately 1.46 (632.8 nm), has an average value of 3.5 μm for the average distance between the long axis, medium axis, and short axis, and has a thermal conductivity of approximately 0.02 W / m·K, with its internal space partitioned in the range of 5 nm to 100 nm. Furthermore, the "average distance of the long axis, medium axis, and short axis of silica shell aerogel" mentioned above refers to the average value of the "average distance of the long axis, medium axis, and short axis of silica shell aerogel," which is calculated by measuring the distances of the long axis, medium axis, and short axis of a single aerogel, as previously stated. Specifically, it refers to the average value calculated from the average distance of the long axis, medium axis, and short axis of aerogels randomly selected from images taken with a microscope (KEYENCE Corporation: Model number VHX-2000).

[0061] An EVA interlayer measuring 5 cm x 5 cm and 1.0 mm thick was prepared by dispersing the prepared silica shell aerogel on an ethylene vinyl acetate substrate (hereinafter referred to as EVA interlayer). Then, a laminated glass was prepared by sandwiching the 1.0 mm thick EVA interlayer with the dispersed silica shell aerogel between two 5 cm x 5 cm, 3 mm thick glass plates as follows. (1) Laminated glass with an EVA interlayer without dispersed silica shell aerogel sandwiched between two 3mm thick glass plates. (2) Laminated glass with a 1.0mm thick EVA interlayer containing 0.1% by mass of silica shell aerogel with an average length of 3.5 μm between the long, medium, and short axes, sandwiched between two 3mm thick glass plates. (3) Laminated glass with a 1.0mm thick EVA interlayer containing 1.0% by mass of silica shell aerogel with an average length of 3.5 μm between the long, medium, and short axes, sandwiched between two 3mm thick glass plates. (4) Laminated glass with a 1.0mm thick EVA interlayer containing 2.0% by mass of silica shell aerogel with an average length of 3.5 μm between the long, medium, and short axes, sandwiched between two 3mm thick glass plates. (5) Laminated glass made by sandwiching a 1.0 mm thick EVA interlayer, which contains 3.0 mass% of silica shell aerogel with an average long-axis, medium-axis, and short-axis distance of 3.5 μm, between two 3 mm thick glass plates. (6) Laminated glass made by sandwiching a 1.0 mm thick EVA interlayer, which contains 4.5 mass% of silica shell aerogel with an average long-axis, medium-axis, and short-axis distance of 3.5 μm, between two 3 mm thick glass plates. (7) Laminated glass made by sandwiching a 1.0 mm thick EVA interlayer, which contains 6.0 mass% of silica shell aerogel with an average long-axis, medium-axis, and short-axis distance of 3.5 μm between two 3 mm thick glass plates.

[0062] The following evaluations were performed on the samples (1) to (7) obtained in this manner. The results are shown in Table 1.

[0063] (Visible Light Transmittance and Solar Radiation Transmittance) Visible light transmittance and solar radiation transmittance were measured using a Shimadzu Corporation SolidSpec-3700DUV measuring instrument (double-beam type). Under conditions of 45-degree incident light and linear polarization, the spectral transmittance at an incident angle of 5° was measured for visible light transmittance, and the spectral transmittance at incident angles of 5°, 30°, 45°, 60°, and 70° was measured for solar radiation transmittance. For visible light, the range was 380 nm to 780 nm, and for solar radiation, the range was 350 nm to 2100 nm. In Table 1, "5°-T" means "incident angle of 5°".

[0064] (Visibility) In addition, visibility was assessed by visual inspection, and the haze value at that time was determined using a spectroscopic haze meter (SH7000) manufactured by Nippon Denshoku Industries Co., Ltd., in accordance with JIS K7136. The results are shown in Table 1. Formula for calculating haze value: H = Td / Tt × 100 H: Haze (cloud value) (%) Td: Diffuse light transmittance (%) Tt: Total light transmittance (%)

[0065]

[0066] When measuring the solar transmittance of laminated glass made by sandwiching a 1 mm thick EVA interlayer with 1.0 mass% of silica shell aerogel between two 5 cm x 5 cm 3 mm thick glass plates, the solar transmittance of laminated glass made by sandwiching a 1 mm thick EVA interlayer without silica shell aerogel between two 5 cm x 5 cm 3 mm thick glass plates was measured. The relative values ​​compared to this were 7.4% at an incident angle of 5°, 7.8% at 30°, 8.5% at 45°, 17.7% at 60°, and 35.2% at 70°, indicating a solar light regulating effect depending on the incident angle. Similarly, other laminated glasses with different aerogel dispersion rates also exhibit a solar light regulating effect. Furthermore, it was found that if the dispersion amount of silica shell aerogel is between 0.1% by mass and 4.5% by mass, the haze value can be kept low, and high visible light transmittance, high visibility, and transparency can be maintained.

[0067] (Example 2) A silica shell aerogel "MT1100" manufactured by Cabot Specialty Chemicals, Inc., which has an internal space partitioned to 5 nm to 100 nm and a thermal conductivity of 0.02 W / m·K, was sieved to classify the aerogels into sizes of 0.2 μm, 3.5 μm, 5.1 μm, 9.9 μm, 16.8 μm, and 23.7 μm based on the average distance of the long axis, medium axis, and short axis. Each of these was dispersed at a concentration of 1.0 mass% relative to the solid content of EVA "UltraSen 751R" manufactured by Tosoh Corporation.

[0068] An EVA interlayer measuring 5 cm x 5 cm and 1.0 mm thick was prepared by dispersing the prepared silica shell aerogel on an ethylene vinyl acetate substrate (hereinafter referred to as EVA interlayer). Then, a laminated glass was prepared by sandwiching the 1.0 mm thick EVA interlayer with the silica shell aerogel dispersed between two 5 cm x 5 cm, 3 mm thick glass plates as follows. (1) Laminated glass made by sandwiching an EVA interlayer without dispersed silica shell aerogel between two 3 mm thick glass plates. (8) Laminated glass made by sandwiching a 1.0 mm thick EVA interlayer containing 1.0 mass% of silica shell aerogel with an average length of 0.2 μm between the long, medium, and short axes between two 3 mm thick glass plates. (9) Laminated glass made by sandwiching a 1.0 mm thick EVA interlayer containing 1.0 mass% of silica shell aerogel with an average length of 3.5 μm between the long, medium, and short axes between two 3 mm thick glass plates. (10) Laminated glass made by sandwiching a 1.0 mm thick EVA interlayer containing 1.0 mass% of silica shell aerogel with an average length of 5.1 μm between the long, medium, and short axes between two 3 mm thick glass plates. (11) Laminated glass made by sandwiching a 1.0 mm thick EVA interlayer containing 1.0 mass% of silica shell aerogel with an average length of 9.9 μm between two 3 mm thick glass plates. (12) Laminated glass made by sandwiching a 1.0 mm thick EVA interlayer containing 1.0 mass% of silica shell aerogel with an average length of 16.8 μm between two 3 mm thick glass plates. (13) Laminated glass made by sandwiching a 1.0 mm thick EVA interlayer containing 1.0 mass% of silica shell aerogel with an average length of 23.7 μm between two 3 mm thick glass plates.

[0069] The samples obtained in this manner (1) and (8) to (13) were evaluated for (visible light transmittance and solar transmittance) and (visibility) as described in (Example 1). These results are shown in Table 2.

[0070]

[0071] When measuring the visible light transmittance and solar radiation transmittance of laminated glass made by sandwiching a 1 mm thick EVA interlayer, in which 1.0 mass% of silica shell aerogel with an average average distance of the long, medium, and short axes of 0.2 μm to 22.3 μm is dispersed between two 3 mm thick glass plates, the solar radiation transmittance of the laminated glass made by sandwiching a 1 mm thick EVA interlayer without dispersed silica shell aerogel between two 5 cm x 5 cm 3 mm thick glass plates is taken as 100%, and the solar radiation transmittance of the laminated glass is measured on a relative basis to that value. When the average of the average distances of the long, medium, and short axes is 0.2 μm, the solar radiation reduction is 6.5% at an incident angle of 5°, 6.9% at an incident angle of 30°, 7.3% at an incident angle of 45°, 19.5% at an incident angle of 60°, and 34.4% at an incident angle of 70°. This shows that other solar radiation-controlled laminated glass with different average values ​​of the average distances depending on the incident angle also has a solar radiation-controlled effect.

[0072] Furthermore, if the average value of the average distance between the long axis, medium axis, and short axis of the silica shell aerogel is 0.2 μm to 16.8 μm, the visible light transmittance is also high, and high visibility, transparency, and a low haze value can be maintained. The average value of the average distance between the long axis, medium axis, and short axis of the silica shell aerogel is preferably 0.2 μm to 16.8 μm, more preferably 0.2 μm to 9.9 μm, and most preferably 0.2 μm to 5.1 μm.

[0073] (Example 3) A silica shell aerogel "MT1100" manufactured by Cabot Specialty Chemicals, Inc., in which the average value of the average distance between the long axis, medium axis, and short axis is 3.5 μm and the internal space is divided into 5 nm to 100 nm sections, and which has a thermal conductivity of 0.02 W / m·K, was prepared by dispersing 1.0 mass% of each component of EVA "UltraSen 751R" manufactured by Tosoh Corporation relative to the solid content.

[0074] EVA interlayers were fabricated using EVA resin in which 1.0% by mass of the prepared silica shell aerogel was dispersed, with thicknesses of 0.1 mm, 0.5 mm, 1.0 mm, 3.0 mm, 5.0 mm, 10.0 mm, and 20 mm, and each EVA interlayer measuring 5 cm x 5 cm. Then, laminated glass was prepared by sandwiching these interlayers between two 3 mm thick glass plates, each measuring 5 cm x 5 cm, as follows. (1) Laminated glass made by sandwiching an EVA interlayer without dispersed silica shell aerogel between two 3 mm thick glass plates (also listed in Tables 1 and 2) (14) Laminated glass made by sandwiching a 0.1 mm thick EVA interlayer with 1.0 mass% of silica shell aerogel dispersed in it, where the average distance between the long, medium, and short axes is 3.5 μm, between two 3 mm thick glass plates (15) Laminated glass made by sandwiching a 0.5 mm thick EVA interlayer with 1.0 mass% of silica shell aerogel dispersed in it, where the average distance between the long, medium, and short axes is 3.5 μm, between two 3 mm thick glass plates (16) Laminated glass made by sandwiching a 1.0 mm thick EVA interlayer with 1.0 mass% of silica shell aerogel dispersed in it, where the average distance between the long, medium, and short axes is 3.5 μm, between two 3 mm thick glass plates (17) Laminated glass made by sandwiching a 3.0 mm thick EVA interlayer film, in which 1.0 mass% of silica shell aerogel with an average length of 3.5 μm between the long, medium, and short axes is dispersed, between two 3 mm thick glass plates. (18) Laminated glass made by sandwiching a 5.0 mm thick EVA interlayer film, in which 1.0 mass% of silica shell aerogel with an average length of 3.5 μm between the long, medium, and short axes is dispersed, between two 3 mm thick glass plates. (19) Laminated glass made by sandwiching a 10.0 mm thick EVA interlayer film, in which 1.0 mass% of silica shell aerogel with an average length of 3.5 μm between the long, medium, and short axes is dispersed, between two 3 mm thick glass plates. (20) Laminated glass in which a 20.0 mm thick EVA interlayer film, in which 1.0 mass% of silica shell aerogel with an average average distance of 3.5 μm between the long axis, medium axis, and short axis is dispersed, is sandwiched between two 3 mm thick glass plates.

[0075] The samples obtained in this manner (1) and (14) to (20) were evaluated for (visible light transmittance and solar transmittance) and (visibility) as described in (Example 1). These results are shown in Table 3.

[0076]

[0077] When measuring the visible light transmittance and solar radiation transmittance of laminated glass, which consists of an EVA interlayer film with a thickness of 0.1 mm to 20.0 mm sandwiched between two 3 mm thick glass plates, and in which 1.0 mass% of silica shell aerogel with an average average distance of the long, medium, and short axes of 3.5 μm is dispersed in the adhesive, relative values ​​compared to the solar radiation transmittance of laminated glass made by sandwiching an EVA interlayer film without dispersed silica shell aerogel between two 3 mm thick glass plates are taken as 100%, the transmittance for the 0.1 mm thickness decreases by 2.1% at an incident angle of 5°, 2.8% at an incident angle of 30°, 3.3% at an incident angle of 45°, 13.6% at an incident angle of 60°, and 19.7% at an incident angle of 70°, it can be seen that there is a solar radiation regulating effect depending on the incident angle. Similarly, other solar-controlled laminated glass with different average distances for the long, medium, and short axes of the aerogel also exhibits a solar-controlled effect.

[0078] Furthermore, if the thickness of the transparent solar light-regulating interlayer containing dispersed silica shell aerogel is 10.0 mm or less, the visible light transmittance is also high, and high visibility, transparency, and a low haze value can be maintained. The thickness of the transparent solar light-regulating interlayer containing dispersed silica shell aerogel is preferably 0.1 to 10 mm, and more preferably 0.1 to 5.0 mm.

[0079] As described above, the present invention provides a transparent solar light-controlling laminated glass for windows that exhibits a large shielding effect not only against sunlight incident from above but also against sunlight incident from a low position, has high visibility, is inexpensive, and has excellent light-controlling performance that is not affected by the direction of sunlight.

[0080] 1 Thermoplastic resin 2 Silica shell aerogel 3 Glass plate 10 Transparent solar light-controlling laminated glass for windows 30 Silica shell aerogel 31 Partition θ Incident angle

Claims

1. Transparent solar light-controlling laminated glass for windows, which is a transparent solar light-controlling laminated glass for bonding to a glass substrate for windows, comprising a solar light-controlling interlayer in which silica shell aerogel, whose internal space is divided into a range of 5 nm to 100 nm, is dispersed in a thermoplastic resin that transmits sunlight, wherein the silica shell aerogel is dispersed in an amount of 0.1% to 4.5% by mass of the total amount of solid content of the solar light-controlling interlayer excluding the silica shell aerogel, and a transparent solar light-controlling laminated glass for windows characterized by sandwiching the interlayer between two glass plates.

2. The interlayer for transparent solar light-regulating laminated glass for windows according to claim 1, wherein the average value of the average distances of the long axis, medium axis, and short axis of the silica shell aerogel is 0.2 μm to 16.8 μm, and the transparent solar light-regulating laminated glass for windows characterized by having the interlayer for laminated glass sandwiched between two glass plates.

3. The interlayer for transparent solar light-controlling laminated glass for windows according to claim 1, wherein the silica shell aerogel is dispersed in an amount of 0.1% to 4.5% by mass relative to the total amount of solids in the solar light-controlling interlayer excluding the silica shell aerogel, and the transparent solar light-controlling laminated glass for windows characterized by having the interlayer for laminated glass sandwiched between two glass plates.

4. The transparent solar light-controlling laminated glass for windows according to claim 1, wherein the thickness of the interlayer for the solar light-controlling laminated glass is 0.1 mm to 5 mm.

5. A method for improving the light control performance using transparent solar light control laminated glass for windows as described in any one of claims 1 to 4.

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