JPH0881238A - Thermal insulation glass - Google Patents

Abstract

PURPOSE: To obtain a thermal insulation glass having excellent thermal insulation effect because of promoting thermal energy incidence indoors form the outside but suppressing thermal energy radiation in the opposite direction when used as a window glass or door glass for buildings, automobiles or streetcars. CONSTITUTION: This thermal insulation glass is a plate glass for blocking a thermal insulation space from the outside, which is obtained by laminating the plate glass surface on the side of a thermal insulation space with a transparent thermal gradient-forming layer having heat capacity and radiation absorptivity respectively <=10% and <=60% of those of the glass base body. A transparent interlayer between the glass base body and the transparent thermal gradient- forming layer may be provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plate glass which exhibits a high heat retaining power when attached to a partition wall. More specifically, the present invention is a sheet glass attached to shut off the inside and outside of a heat retaining space such as a room of a building or a vehicle, and promotes the transfer of heat from the outside into the heat retaining space. The present invention relates to a plate glass capable of maintaining a high room temperature by suppressing the transfer of heat from the heat retaining space to the outside.

[0002]

2. Description of the Related Art Generally, as a heat insulating glass, there is known a glass made of a material such as transparent glass or far infrared transmitting glass which easily transmits a radiation ray, or a glass in which a heating wire for heating is incorporated. However, the former emits radiation from a heat source to warm the room temperature, while radiating radiation from the room to the outside, it tends to accelerate the temperature drop in the room at night, while the latter In order to obtain continuous heat retention, it is necessary to constantly supply electric energy, which is not a good idea in terms of energy consumption. By the way, from the viewpoint of effective use of energy,
It is desirable to use a heat insulating glass that has a function of smoothly taking in heat energy from the outside or outside the vehicle, such as sunlight, and blocking the emission of heat energy from the inside, but such a thing has not been realized yet.

[0003]

DISCLOSURE OF THE INVENTION The present invention smoothly injects thermal energy into a room or a vehicle that needs to be kept warm, such as a window glass for a building or a vehicle, and further, the thermal energy from the room or the vehicle. The purpose of the present invention is to provide a heat insulating glass having a function of blocking the radiation of.

[0004]

DISCLOSURE OF THE INVENTION The inventor of the present invention intends to develop a window glass which promotes the incidence of heat energy from the outside and suppresses the radiation of the heat energy from the inside to efficiently keep the inside warm. As a result of repeated intensive research, the objective was achieved by laminating one or more transparent layers having a specific heat transfer relationship on the inner side of the glass substrate and forming a heat gradient from the outside to the inside. Based on this finding, the present invention has been completed.

That is, the present invention is a plate glass for isolating the heat retaining space from the outside, and the surface of the heat retaining space is preferably 10% or less with respect to the heat volume and radiant heat absorption rate of the glass substrate. A heat-insulating glass comprising a transparent thermal gradient forming layer having a heat capacity and a radiant heat absorption rate of 5% or less and 60% or less, preferably 50% or less, optionally via a transparent intermediate layer or layers. It is provided.

The heat volume referred to here is expressed by the following equation, where Q is the heat volume. Q = V · d · C (1) = W · C (1 ′) where V is the total volume (cm ³ ), d is the density (g / cm ³ ),
C indicates specific heat (cal / g / ° C.), and W indicates total weight (g).

The specific heat C in this equation is unique to each material and slightly changes depending on the temperature. In the present invention, the numerical value measured for each material at the outside air temperature is used. This measurement can be performed using a specific heat measuring device according to a conventional method.

The radiant heat absorptivity referred to here is the ratio of the radiant temperature of sunlight to the temperature that is lowered when the sunlight passes through the prescribed material, expressed as a percentage. The radiant heat absorption rate X of can be calculated according to the following equation.

[0009]

[Equation 1]

Here, T is the radiation temperature of sunlight, and T'is the radiation temperature after the sunlight has passed through a predetermined material. Next, explaining the basic principle of the present invention, heat transfer includes convection,
There are three types of conduction and radiation, which are usually done by a combination thereof.

The heat flow q due to convection and conduction in the normal state is represented by the following equation. q = α ₁ (T _r −T ₁ ) = λ / L (T ₁ −T ₂ ) = α ₀ (T ₂ −T ₀ ) ... (2) where α ₁ is the heat transfer coefficient of the high temperature fluid, α ₀ is the heat transfer coefficient of the low temperature fluid, T _r is the temperature of the high temperature fluid, T ₁ is the temperature of the high temperature side partition wall surface, T ₂ is the temperature of the low temperature side partition wall surface, T ₀ is the low temperature fluid temperature, λ is the thermal conductivity of the partition, and L is the thickness of the partition.

As can be seen from this equation, heat flows from the high temperature fluid to the high temperature side surface of the partition wall, and then heat is conducted in the partition wall from the surface in contact with the high temperature fluid to the surface in contact with the low temperature fluid. And flows from the low temperature side surface of the partition wall to the low temperature fluid.

On the other hand, for a transparent body such as glass,
Although it transmits the light of short wavelength of sunlight, it absorbs the light of secondary long wavelength that is generated secondarily. The internal temperature tends to gradually rise due to radiant heat without radiating heat to the outside. For example, when sunlight is radiated from the outside into the room that is shielded from the outside air by the window glass, the room is heated by the short wavelength light of the sunlight, and the long wavelength light secondarily generated in the room, for example, far infrared rays. The room temperature gradually rises to shut off. At this time, the window glass plays a role of suppressing the radiation from the room and enhancing the heat retention effect.

That is, normally, the temperature of the window glass, which has become high temperature by absorbing radiant heat, is high in the central portion in the thickness direction thereof, and the temperature of the surface which is in contact with the outside atmosphere and is cooled is low. . When the sunlight is strong, the temperature of the central portion in the thickness direction of the glass is higher than the temperature of the air that is trapped inside the room and is heated to a high temperature, and does not fall below at least the same temperature. Therefore, the heat in the room does not flow through the glass to the outside.

By the way, a high-temperature object placed in the atmosphere constantly loses heat due to convection of air, and its temperature drops. Then, the rate of decrease in temperature becomes faster as the specific heat of the object is smaller and the volume thereof is smaller. That is, the smaller the product of specific heat and volume, so-called heat volume, the faster the speed.

Therefore, when a layer having a small heat volume is formed on the atmosphere side of the glass substrate, the temperature of the surface of the transparent layer on the atmosphere side drops rapidly unless the heat absorbed by the convection of air remains unchanged. Then, since the difference between the temperature of the central portion in the thickness direction of the glass and the temperature of the glass surface on the atmosphere side becomes large, thermal energy flows toward the glass surface on the atmosphere side,
The thermal energy accumulated in the entire glass is reduced and the temperature of the glass is lowered. As a result, the thermal energy inside the room also begins to flow toward the outside.

On the contrary, when a layer having a small heat volume is formed on the surface of the glass substrate on the indoor side, that is, the surface in contact with the atmosphere, the flow of thermal energy is directed from the atmospheric side to the room.

Further, generally, when the radiation heat absorption is large, the temperature of the object rises when it is irradiated with sunlight, so if the radiation and absorption rate of the layer formed on the glass surface is large, The temperature becomes higher than that of glass, the movement of radiation energy incident from the atmosphere side is blocked, and it does not contribute to the temperature rise in the room.

Further, when the irradiation of sunlight is weakened or disappears, the temperature of the glass substrate becomes lower due to convection of the atmosphere than the temperature of the glass substrate due to the absorption of radiant heat, and the temperature of the glass substrate becomes low. Then, the heat that is not radiated to the outside due to the temperature rise of the glass substrate starts to radiate to the outside when the temperature of the glass substrate decreases. When a transparent layer with a small radiant heat absorption rate is formed on the indoor surface of the glass substrate, the radiant heat directed to the glass surface passes through the transparent layer with a small radiant heat absorption rate and is largely absorbed by the glass surface. Temperature rises. When a transparent layer having a small heat capacity is formed on the surface of the glass substrate on the inner side of the glass substrate, when cooled by convection, the temperature of the transparent layer becomes faster. Therefore, a transparent layer having a small radiant heat absorptivity and a small heat volume with respect to the glass substrate, that is, a transparent layer having a fast temperature drop rate and a small temperature rise is laminated on the glass substrate on the inner surface of the glass substrate. This makes it possible to reduce the temperature difference between the surface temperature of the glass surface facing the outside air and the temperature of the transparent layer facing the indoor side.

Since the heat flow q due to conduction is expressed by the equation (2) as q = λ / L (T ₁ -T ₂ ), (T ₁ -T ₂ ), that is, the surface temperature on the indoor side, If the difference in the surface temperature on the outside air side becomes small, the heat conductivity λ can be made small, and the heat flow can be made small without increasing the thickness L of the glass.

When heat flows from the high temperature side to the low temperature side due to convection and conduction, as can be seen from the equation of heat flow in the above equation (2), the heat inside (a) flows convectively to the glass surface inside the room. The heat, (b) the heat flowing from the glass surface on the indoor side to the glass surface on the outside air side, and (c) the heat flowing from the glass surface on the outside air side to the outside air are all equal. Therefore, the heat flowing from the glass surface on the indoor side to the glass surface on the outside air, that is, the heat flow due to conduction, is reduced by decreasing the temperature inside the room to reduce the overall convection and heat flow due to conduction. , The internal heat retention effect can be obtained. That is, by utilizing the radiant heat from the inside to the outside air, the heat radiated to the outside air by convection and conduction can be reduced, and the heat retention effect can be enhanced.

As a result of various studies based on such a basic principle, the present inventors found that the glass and the transparent layer laminated to form a thermal gradient on the inner surface of the glass are transparent to the heat capacity of the glass substrate. The ratio of the heat capacity of the thermal gradient forming layer is 1
The ratio of the radiation absorptivity of the transparent thermal gradient forming layer to the radiation absorptivity of the glass substrate is 6% or less, preferably 0% or less.
It has been found that when it is 0% or less, preferably 50% or less, the effect as a practical heat insulating glass is exhibited.

Therefore, in the present invention, between the heat volume Q ₁ and the radiation absorption rate X ₁ of the glass substrate and the heat volume Q ₂ and the radiation absorption rate X ₂ of the transparent thermal gradient forming layer laminated on the inner surface thereof. Must have the following relationships: 0.10Q ₁ ≧ Q ₂ (3) 0.60X ₁ ≧ X ₂ (4)

For that purpose, a material having a small specific heat is used as a material of the transparent heat gradient forming layer, and a substance capable of absorbing sunlight is mixed to obtain a heat capacity and a radiation absorption rate per unit volume of the material itself. Create a material that satisfies the above relational expressions by lowering the thickness and decreasing the layer thickness, selecting a material with a high specific heat and radiant heat absorption coefficient as the glass substrate, and increasing the thickness to increase the heat capacity. To do.

The plate glass used in the present invention includes:
As long as it is transparent, ordinary glass, potash glass, lead glass,
Although any special glass such as heat ray absorbing glass or heat ray reflecting glass can be used, the above formula (3)
It is advantageous to select a material having a large specific heat and radiant heat absorption rate in that the relationship of (4) and (4) can be easily satisfied. The plate glass is usually colorless and transparent, but may be colored in blue, red, yellow, pale brown, gray or the like if desired. The thickness of this plate glass is usually about 1 to 10 mm.

On the other hand, as the material of the transparent thermal gradient forming layer,
Glass having a composition different from that of the glass substrate, a vapor-deposited film of metal or ceramics, or the like may be used, but plastics are preferable in that various materials having various physical properties can be easily and inexpensively obtained and the lamination process is easy.

Suitable plastics as the material of the transparent thermal gradient forming layer include, for example, high-pressure polyethylene, low-pressure polyethylene, ethylene-vinyl acetate copolymer, ethylene-acrylic acid or acrylic ester copolymer, metal-containing ethylene. -Acrylic acid copolymer, ethylene-propylene copolymer, ethylene-vinyl chloride-vinyl acetate copolymer, polypropylene, propylene-vinyl chloride copolymer, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyethylene terephthalate, ABS resin , Polyamide, polyacetal, fluororesin, acrylic resin, methacrylic resin, polycarbonate, urea resin, melamine resin, unsaturated polyester, silicon resin, epoxy resin and the like. These plastics can be blended with various commonly used additives,
The heat capacity and radiant heat absorptivity can be adjusted by changing the type, combination and addition amount of these additives. These may be used alone or as a mixture of two or more kinds, but it is necessary that they are laminated on the glass substrate while keeping the transparent state.

The method for laminating the glass substrate and the transparent thermal gradient forming layer in the present invention is a method in which a transparent layer formed in advance in the form of a film or sheet is adhered to the surface of the glass substrate by heat fusion or adhesion, or plastic is suitable. A method of dissolving it in a different solvent and coating it on a glass substrate, drying and solidifying it, a method of fixing it by chemical vapor deposition, vacuum vapor deposition, electroless plating, etc.
It can be arbitrarily selected from the methods conventionally used for laminating other materials on the glass substrate. Thus, the transparent thermal gradient forming layer having a thickness of 1 to 1000 μm, preferably 10 to 500 μm is laminated on the glass substrate.

Another preferred embodiment of the present invention is
One or more transparent intermediate layers are interposed between the glass substrate and the transparent thermal gradient forming layer. Finally, as long as the relations of the above formulas (3) and (4) are satisfied between the glass substrate and the transparent thermal gradient forming layer, the intermediate layer is
Although any transparent layer can be used, in order to form a thermal gradient in which heat energy is smoothly transferred from the outside into the heat retaining space, the heat capacity and the radiant heat absorption coefficient of the glass substrate are more preferable than those of the glass substrate. It is advantageous to use transparent layers that are small and have a heat volume and radiant heat absorption coefficient that are larger than those of the transparent thermal gradient forming layers.

[0030]

INDUSTRIAL APPLICABILITY When the heat insulating glass of the present invention is used as a window glass or a door glass of a building, a window glass or a door glass of an automobile or a train, it promotes the incidence of heat energy from the outside into the room. Since it suppresses the radiation of heat energy to the outside, it has a very excellent heat retaining effect.

[0031]

EXAMPLES The present invention will be described in more detail with reference to examples.

Reference Example Transparent ordinary glass with a thickness of 3 mm (radiant heat absorption rate 7.9%)
5 types of commercially available films made of materials having different radiant heat absorptivities, namely, heat-shielding polyester film (A), vinyl chloride resin film (B), polyester film (C), and modified acrylic resin film (D) ), An acrylic resin film (E) is laminated to prepare a sample, which is irradiated with an infrared lamp from the side opposite to the film side to be placed in contact with the surfaces of the glass only portion and the film laminated portion, respectively. The change in surface temperature was measured by the thermometer. Table 1 shows the results. The ratio of heat absorption to glass in Table 1 is the ratio of the heat absorption coefficient of each sample to the heat absorption coefficient of glass.

[0033]

[Table 1]

From these results, when the transparent films (D) and (E) having a radiant heat absorptivity of 60% or less with respect to the radiant heat absorptivity of the glass substrate are laminated, the surface temperature becomes lower than that of the glass. It can be seen that the heat transfer from the side to the film side is promoted, but if the radiation heat absorption is larger than this, the surface temperature becomes high and the heat transfer is blocked.

Example 1 and Comparative Example 1 Kayacryl resin P4838 (trade name of a copolymer of acrylic ester and styrene manufactured by Nippon Kayaku Co., Ltd.) was dissolved in a solvent, and modified dimethyl silicone oil SF8 was added thereto.
419 (trade name of Toray Dow Corning Silicone Oil Co., Ltd.) was added to prepare a coating film forming composition. Styrofoam box with only the front open (length 33 cm, width 3)
On the open surface of 9 cm, depth of 24 cm, transparent ordinary flat glass with a thickness of 3 mm (radiation absorption rate 7.9%, heat capacity 193.1)
cal / ° C) (control), the above-mentioned composition for forming a coating film was applied to the inner surface of the glass to form a layer having a radiant heat absorption rate of 1.9% and a heat capacity of 0.26 cal / ° C ( Example 1) and three test boxes equipped with the above-mentioned layers formed on the outer surface of the glass (Comparative Example 1) were prepared,
These were arranged in parallel to the sun so as to be in the same direction, and the time-dependent change in the temperature inside each box was measured.
The results are shown in Table 2.

[0036]

[Table 2]

From these results, when a predetermined film is laminated on the inner side of the glass (Example 1), the heat retaining effect is improved, but when laminated on the atmosphere side (Comparative Example 1), the heat retaining effect is rather obtained. It can be seen that a decrease in the effect is observed. 3
The decrease in the internal temperature after 0 minutes is due to the decrease in the amount of sunlight.

Example 2 After cleaning the surface of a plate glass having a thickness of 3 mm (50 × 50 cm, radiant heat absorption rate 7.9%, heat capacity 375 cal / ° C.), organosilane K was used as a silane coupling agent.
BM503 (manufactured by Shin-Etsu Chemical Co., Ltd.) is coated, and kayakryl resin P4838 (manufactured by Nippon Kayaku Co., Ltd., a trade name of a copolymer of acrylic acid ester and styrene) is coated on this with ethyl acetate, toluene, isopropanol, and butyl acetate. Dissolved in a mixed solvent composed of methanol, added 0.03 parts by weight of modified dimethyl silicone oil SF8419 (trade name of Toray Dow Corning Silicone Oil Co., Ltd.), mixed and applied, and then dried to form an intermediate layer having a thickness of 5 μm. Was formed. The radiant heat absorptivity of this coating film was 1.9% with respect to the radiant heat absorptivity of the glass substrate, and the heat volume was 0.5 cal / ° C (24.1 with respect to the heat capacity of the glass substrate).
%)Met.

After the coating film is sufficiently dried, an emulsion type dimethyl silicone oil SH is further formed on the coating film.
7028 (trade name, manufactured by Toray Dow Corning Silicone Oil Co., Ltd., solid content: 30%) was diluted 5 times with water to form a coating having a thickness of 1 μm. The radiant heat absorptivity of this coating is 58 with respect to the intermediate layer.
%, The heat volume was 0.09 cal / ° C.

A 50 cm cubic box, one surface of which was opened with a styrofoam plate having a thickness of 5 mm, was prepared, the front surface of the inner wall was covered with a black cloth, and the above-mentioned heat insulating glass or 3 mm transparent glass was attached to the open surface of two boxes. I prepared a warm box. Using this heat insulation box, the same solar irradiation experiment as in Example 1 was conducted, and the results are shown in FIG. The solid line in the figure indicates the heat insulating glass of the present invention,
The broken line is a graph for transparent glass.

Example 3 A transparent plate glass (50 × 50 cm, radiant heat absorption rate 7.9%, heat volume 375 cal / ° C.) having a thickness of 3 mm was applied to a polyester resin (density 0.92 g / cm ³ , specific heat 0.55). 50 μm-thick intermediate layer (radiant heat absorption rate 15.8%, heat volume 6.3 cal /
C.) was formed. Then, on this intermediate layer, Example 2
In the same manner as in the case of forming the intermediate layer of 1., a coating film composed of a copolymer of acrylic ester and styrene and modified dimethyl silicone oil (the radiation absorption rate is 1.9% with respect to the intermediate layer, the heat capacity is 3.2% for the middle layer) 2
A heat insulating glass having a three-layer structure was produced by forming the heat insulating glass with a thickness of μm.

Next, with respect to this heat insulating glass, Example 2
A solar irradiation experiment similar to that was conducted, and the result is shown by the solid line graph in FIG. For comparison, the results of the same experiment performed on the heat insulating glass in which only the intermediate layer is laminated on the same transparent plate glass (dashed line) and the transparent plate glass only (broken line) are also shown. From these results, it can be seen that the heat retaining effect is further improved when the intermediate layer is interposed.

Example 4 Heat ray absorbing plate glass having a length of 33 cm, a width of 39 cm and a thickness of 5 mm (radiant heat absorption rate 32.8%, heat volume 321.8 cal)
/ ° C) and an ordinary transparent plate glass with a thickness of 1 mm (radiant heat absorption rate 7.9%, heat volume 64, 3 cal / ° C) are laminated to form a double glass, and the surface of the transparent glass is the middle of Example 2. A coating film having the same thickness as the layer and having a thickness of 5 μm (radiation heat absorptivity was 24.1% with respect to an ordinary transparent glass plate having a thickness of 1 mm and a heat capacity of 0.39%) was laminated. About this, Example 1
Table 3 shows the results of testing the heat retention effect at the initial temperature of 19 ° C in the same manner as in. In addition, the case where only double glazing was used was shown as a control.

[0044]

[Table 3]

From these results, it can be seen that an average internal temperature of 2 ° C. higher can be obtained by providing a coating layer for double glazing.

Example 5 Two windows of the same size having a height of 2.2 m, a height of 2.2 m, a frontage of 2.7 m, and a depth of 3.6 m having a window of 1.8 m in length and 1.8 m in width, and ordinary windows are provided for each window. A transparent plate glass (thickness: 3 mm) and the heat insulating glass obtained in Example 1 were attached, a heater having the same capacity was installed in this room, and the room temperature was checked by operating it at night. The results are shown as a graph in FIG. The solid line in the figure is heat insulating glass, and the broken line is ordinary plate glass. From these results, it can be seen that the heat insulating glass of the present invention exhibits a heat insulating effect as high as 1.5 to 3 ° C. as compared with ordinary plate glass.

Example 6 Using a reinforced concrete 12-story condominium located in Chiyoda-ku, Tokyo, which has rooms of the same structure on the 8th and 9th floors facing the same direction, from 10 am to 9 pm in each period ,
A mounting test was carried out on the heat insulating glass obtained in Example 2 and an ordinary transparent plate glass. The floor area of this room is 31m ² ,
The height was 2.7 m and the window glass area was 12 m ² . In this case, the glass had a heat capacity of 30,000 cal / ° C and the coating film had a heat capacity of 23.87 cal / ° C. The result is shown in FIG. The outside air temperature (chain line) is also shown for reference. As can be seen from this figure, when the heat insulating glass of the present invention is used, a heat insulating effect higher by 1.5 to 4 ° C. than that of the ordinary glass can be obtained over 24 hours.

Example 7 Floor space in the vehicle 55.1 m ² , height in the vehicle 2.1 m, window area 2
^Two 0m ² vehicles of the same type were connected, and J in Kitakyushu in late November
A mounting test of the heat insulating glass of the present invention was performed using the R line branch line. As a measuring instrument, a computer built-in thermo-hygrometer manufactured by Shinei Co., Ltd. was used, and the thermo-hygrometer was installed at a height of 1 m in the center of the vehicle. The climate at this time was rain, and the outside temperature was about 13.
5 ° C. Record the temperature inside the car when passing each station,
A graph is shown in FIG. The broken line in the figure is the temperature measurement value of a vehicle equipped with a normal window glass (thickness 5 mm, heat capacity 50000 cal / ° C, radiant heat absorption rate 12.5%), and the solid line is a 5 μm thick coating on the inside surface of the vehicle. Membrane (heat volume 39.7
The temperature measurement value of a vehicle provided with a heat insulating glass laminated with 8 cal / ° C. and a radiant heat absorption rate of 1.9% is shown.

[Brief description of drawings]

FIG. 1 is a graph showing a heat retaining effect in Example 2.

FIG. 2 is a graph showing the heat retaining effect in Example 3.

FIG. 3 is a graph showing the heat retaining effect in Example 5.

FIG. 4 is a graph showing the heat retaining effect in Example 6.

FIG. 5 is a graph showing the heat retaining effect in Example 7.

Claims (2)

[Claims] 1. A plate glass for isolating a heat insulating space from the outside, wherein the surface of the heat insulating space is 10% or less and 6% with respect to the heat volume and the radiant heat absorption rate of the glass substrate, respectively.
A heat-insulating glass comprising a transparent heat gradient forming layer having a heat capacity of 0% or less and a radiant heat absorptivity. 2. A heat volume and a radiant heat absorption between the glass substrate and the transparent heat gradient forming layer are smaller than those of the glass substrate and larger than those of the transparent heat gradient forming layer. The heat insulating glass according to claim 1, wherein one or more transparent intermediate layers are interposed.