JP2006038123A - Vacuum thermal insulation material and glass composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To lower the thermal conductivity of a vacuum thermal insulating material by lowering the thermal conductivity of the glass fiber material used for the core to lower the thermal conduction of a core solid component for the vacuum thermal insulating material, and to provide the vacuum insulating material that raises the productivity by reducing the required thermal energy etc. for making the fibers. <P>SOLUTION: The vacuum insulating material 1 is provided with the core material 2 consisting of the glass fibers and the external packaging material 4 with gas barrier properties to cover the core material 2 and the inside of the external packaging material 4 is decompressed and sealed tightly. The glass fiber contains at least one or more kinds of alkali metal oxide in the range of 20-40 wt.% in the glass composition and the particular intermediate oxide and the thermal conductivity of the glass fiber material is 1 W/mK or lower. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a vacuum heat insulating material and a glass composition.

  In recent years, energy saving has been desired for the purpose of preventing global warming, and energy saving has been promoted for consumer devices. In particular, with respect to a refrigerator-freezer, a heat insulating material having excellent heat insulating properties is required from the viewpoint of efficiently using cold heat.

  As a general heat insulating material, a fiber body such as glass wool or a foam body such as urethane foam is used. However, it is necessary to increase the thickness of the heat insulating material in order to improve the heat insulating properties of these heat insulating materials. Therefore, when there is a limit to the space where the heat insulating material can be installed, or when space saving or effective use of the space is necessary, the conventional heat insulating material is not desirable.

  As a means for solving such a problem, there are a core material made of a porous body and a vacuum heat insulating material configured by covering the core material with an outer packaging material and sealing the inside under reduced pressure. In recent years, vacuum heat insulating materials that are further superior in heat insulating performance have been demanded in the face of intensifying competition for energy saving in recent years.

  In general, heat transfer of a heat insulating material is caused by heat conduction, radiation, and convective heat transfer between a solid and a gas component. On the other hand, the vacuum heat insulating material formed by reducing the pressure inside the outer packaging material has little effect on the heat conduction and convective heat transfer of the gas component. In addition, there is almost no contribution of radiation when used in a temperature range below room temperature.

  Therefore, it is important to suppress the heat conduction of the solid component in the vacuum heat insulating material applied to a cold insulation device used at room temperature or lower. Thus, various fiber materials have been reported as a core material for vacuum heat insulation excellent in heat insulation performance.

  For example, a vacuum heat insulating material in which inorganic fibers having an average fiber length of 1 mm or less are oriented in a direction perpendicular to the direction of heat conduction has been proposed (see, for example, Patent Document 1).

  With this configuration, the heat conduction of the solid component in the heat transfer direction does not occur when heat is transmitted through one fiber, but heat is transferred to adjacent fibers one after another through contact points between the fibers. As a result, heat conduction occurs in the heat transfer direction. Therefore, heat conduction is suppressed by the contact thermal resistance between the fibers as compared with a core material in which one fiber directly transfers heat in the heat transfer direction.

On the other hand, as a glass fiber used as a heat insulating material under normal pressure, a fiber heat insulating material in which Al ₂ O ₃ is decreased and B ₂ O ₃ is increased in the glass composition has been proposed (for example, Patent Document 2). ).

With this configuration, it is possible to reduce the viscosity characteristics while providing the durability required as a heat insulating material, and thus it is possible to reduce the thermal energy required during manufacturing.
Japanese Patent Laid-Open No. 9-4785 Japanese translation of PCT publication No. 5-502432

  However, in a vacuum heat insulating material, when applying an aggregate of glass fibers as a core material, heat transfer of a gas component can be further suppressed as compared with the heat insulating material under normal pressure, so the heat transfer is a solid component. The heat conduction due to occupies the majority.

  Therefore, in the above conventional configuration, it is assumed that general-purpose glass wool is used for the core material of the vacuum heat insulating material, the heat conduction of the inorganic fiber itself is large, and the heat conduction of the solid component most important for the heat insulating performance of the vacuum heat insulating material is increased. Therefore, there has been a problem that the core material itself hinders the reduction of the thermal conductivity of the vacuum heat insulating material.

  On the other hand, when an aggregate of glass fibers is used as it is as a heat insulating material under normal pressure, this heat insulating material exhibits its heat insulating effect by suppressing convection particularly in the heat transfer element. In addition, among the heat conduction of the solid and gas components which are heat transfer elements in that case, the heat conduction by the gas components is much greater, and the heat conduction of the solid components by the glass fibers themselves is not important for the overall heat insulating material.

  Therefore, the thermal conductivity of the glass composition itself in the glass fiber has not been sufficiently studied so far. Furthermore, conventional glass fibers for heat insulating materials must have high durability so that they do not deteriorate in quality even when left in the atmosphere for a long period of time. Increasing the metal oxide has been difficult to implement due to the problem of decreased durability.

  The present invention solves the above-mentioned conventional problems, while maintaining the durability of the glass fiber used for the core material, lowering the material thermal conductivity of the glass fiber and reducing the thermal conductivity of the vacuum heat insulating material. The purpose is to plan.

  In order to achieve the above object, the vacuum heat insulating material of the present invention is such that the glass fiber constituting the core material has a total of 20% by weight or more and 40% by weight or less of at least one alkali metal oxide in the glass composition. The glass fiber material has a thermal conductivity of 1 W / mK or less.

  In the composition of glass fiber used as a conventional heat insulating material, the content of alkali metal oxide is about 14 to 18% by weight. This is because it can be made into a glass having a low viscosity characteristic by containing a large amount of alkali metal oxide, so that the thermal energy at the time of fiber molding can be reduced, but in order to ensure durability over a long period of time, more than this This is because it cannot be increased.

  On the other hand, the glass fiber used as the core material of the vacuum heat insulating material according to the present invention contains an alkali metal oxide in a range of 20 wt% to 40 wt%.

  In terms of glass structure, alkali metal oxides have the property that the network structure of glass is particularly easy to cut. In oxide glass, a large amount of non-bridging oxygen is created in the network structure, making the glass structure extremely unstable. There is. This is presumably because the alkali metal has a strong electric attractive force, and the network structure is cut by the substitution of the covalent bond with the bridging oxygen in the glass network structure to the ionic bond with the alkali metal.

  Therefore, since the glass network structure can be cut by increasing the alkali metal oxide in the glass component, the heat conduction of the non-crosslinked oxygen portion in the glass is suppressed, and the thermal resistance inside the glass increases. .

  Furthermore, the glass fiber according to the present invention improves the glass structure balance in which the non-crosslinked oxygen portion is weakened by a large amount of alkali metal oxide by including a component that forms a network structure of a part of glass called an intermediate oxide. The durability required as a heat insulating material can be secured.

  On the other hand, by substituting partly with a specific intermediate oxide whose network structure itself has a weaker bonding strength than the network-forming oxide, which is the main component, the vibration capacity of thermal energy at the joint increases, resulting in heat transfer loss. Will increase.

  From the above, the glass composition of the present invention has a significantly reduced thermal conductivity, and includes an increase in alkali metal oxide and a specific intermediate oxide, thereby maintaining the durability of the glass alone while maintaining durability. The rate can be 1 W / mK or less.

  The vacuum heat insulating material of the present invention is a glass fiber used as a core material, and contains a large amount of an alkali metal oxide and a specific intermediate oxide, so that the glass used as a conventional glass fiber while maintaining durability. The thermal conductivity can be greatly reduced as compared with the composition, and the heat insulating performance of the vacuum heat insulating material can be dramatically improved.

  Moreover, since it has a low viscosity characteristic by containing many alkali metal oxides, productivity in glass melting, a fiberization process, etc. improves. Furthermore, it is easy to biodegrade, and even if it is taken in by one person, it is difficult to accumulate and is highly safe.

The invention according to claim 1 includes a core material made of glass fiber and an outer packaging material having a gas barrier property that covers the core material, and the inside of the outer packaging material is sealed under reduced pressure, and the glass fiber is The glass composition contains at least one alkali metal oxide in a total range of 20% by weight to 40% by weight and TiO ₂ in a range of 0.1% by weight to 20% by weight. There is a vacuum heat insulating material in which the thermal conductivity of the glass fiber material is 1 W / mK or less.

Therefore, the composition of the glass fiber as the core material contains 20% to 40% by weight of the alkali metal oxide, so that the glass network structure is cut, and in addition, TiO ₂ also weakens the bonding force of the network structure. Therefore, since the transmission of thermal vibration inside the glass is disturbed, the thermal conductivity of the glass composition itself can be greatly reduced.

Furthermore, TiO ₂ is durable because it contains TiO ₂ even though it contains a large amount of alkali metal oxides in order to suppress ion diffusion inside the glass and improve durability even if non-crosslinked parts occur. Can maintain sex.

  Moreover, the increase of the alkali metal oxide in a glass composition can reduce a viscosity characteristic remarkably, and can significantly reduce the thermal energy required for fiberization and the core material shaping | molding for vacuum heat insulating materials.

  With the above action, the heat conduction of the solid component transmitted through the glass fiber itself can be suppressed, so that not only the heat insulating performance of the vacuum heat insulating material is further improved, but also the durability important for the glass fiber can be secured.

  Further, if the alkali metal oxide exceeds 40% by weight, it becomes difficult to ensure water resistance within a range where vitrification is stable, and if it is less than 20% by weight, the glass thermal conductivity becomes large. The metal oxide is desirably 20% by weight or more and 40% by weight or less.

Further, TiO ₂ is both the nature of the thermal conductivity reduction and durability improvement can not be obtained on the characteristics of particular thermal conductivity reduction is less than 0.1 wt%, and the TiO ₂ is too large loss permeation Since the tendency is strong and there is a risk that the glass fiber cannot be stably obtained, 20% by weight or less is preferable.

In addition, as the alkali metal oxide, the larger the atomic number, the more difficult it is to transmit thermal vibration. Therefore, when Cs ₂ O is used, the thermal conductivity can be further reduced, but from the viewpoint of cost, it is often contained in recycled glass. Productivity is good when Na ₂ O or K ₂ O contained in silica sand is used.

The invention according to claim 2 includes a core material made of glass fiber and an outer packaging material having a gas barrier property that covers the core material, and the inside of the outer packaging material is sealed under reduced pressure, and the glass fiber is The glass composition contains at least one alkali metal oxide in a total amount of 20% by weight or more and 40% by weight or less, and ZrO ₂ in a range of 0.1% by weight or more and 20% by weight or less. There is a vacuum heat insulating material in which the thermal conductivity of the glass fiber material is 1 W / mK or less.

Therefore, the composition of the glass fiber as the core material contains 20% to 40% by weight of an alkali metal oxide to cut the glass network structure, and in addition, ZrO ₂ is bonded to the network structure like TiO _2. In order to weaken the force, the transmission of thermal vibration inside the glass is disturbed, so that the thermal conductivity of the glass composition itself can be greatly reduced.

Furthermore, since ZrO ₂ can improve the durability against alkali in the network structure in which the non-crosslinked portion is generated, the durability can be maintained even if it contains a large amount of alkali metal oxide.

  With the above action, the heat conduction of the solid component transmitted through the glass fiber itself can be suppressed, so that not only the heat insulation performance of the vacuum heat insulating material is further improved, but also an important durability as a glass fiber can be secured, and the glass can be stably supplied. The fiber can be supplied.

ZrO ₂ has both the effect of reducing the thermal conductivity and the property of improving durability. However, if it is less than 0.1% by weight, the property cannot be obtained, and it becomes easy to devitrify by increasing the ZrO ₂ component. It is preferably 20% by weight or less.

  The invention according to claim 3 includes a core material made of glass fiber and an outer packaging material having a gas barrier property that covers the core material, and the inside of the outer packaging material is sealed under reduced pressure, and the glass fiber is The glass composition contains at least one or more kinds of alkali metal oxides in a total range of 20% by weight to 40% by weight and ZnO in a range of 0.1% by weight to 30% by weight. A vacuum heat insulating material in which the thermal conductivity of the glass fiber material is 1 W / mK or less.

Therefore, the composition of the glass fiber as the core material contains 20% to 40% by weight of alkali metal oxide to cut the glass network structure, and in addition, ZnO has a network structure like TiO ₂ and ZrO _2. In addition to weakening the bonding force, the number of cross-linking coordination is divalent, so that there is little transmission of thermal vibration inside the glass, and the thermal conductivity of the glass composition itself can be greatly reduced.

  Furthermore, since ZnO improves the durability of the glass, the durability can be maintained even if it contains a large amount of alkali metal oxide.

In addition, ZnO is an intermediate oxide that is less susceptible to devitrification than TiO ₂ and ZrO ₂ , and has a property of being easily vitrified. Therefore, in order to improve durability, a large amount of ZrO ₂ is included in the glass composition. In addition, glass fiber can be molded stably.

  With the above action, the heat conduction of the solid component transmitted through the glass fiber itself can be suppressed, so that not only the heat insulation performance of the vacuum heat insulating material is further improved, but also an important durability as a glass fiber can be secured, and the glass can be stably supplied. The fiber can be supplied.

  ZnO has both the effect of reducing the thermal conductivity and the property of improving the durability, but if it is less than 0.1% by weight, the characteristics cannot be obtained, and the raw material cost is increased, so 30% by weight or less is preferable.

  The invention according to claim 4 includes at least one kind of alkaline earth metal oxide, and the total amount of the alkaline earth metal oxide is in the range of 1% by weight to 15% by weight. It is a vacuum heat insulating material as described in any one of claim | item 3.

  When an alkaline earth metal oxide is contained in the glass composition, durability is improved because it functions to fill the network structure of the glass.

  Therefore, even in the glass composition of the present invention in which the content of the alkali metal oxide is increased and the non-crosslinked region is large, the water resistance can be increased by containing the alkaline earth metal oxide. Furthermore, about CaO, SrO, and BaO, the thermal conductivity of glass can be reduced, without reducing durability, It is more preferable to use these. Of these, BaO is preferable because it has the highest thermal conductivity reduction effect.

  Moreover, since the alkaline earth metal oxide can reduce the viscosity characteristic at high temperature, it can reduce the thermal energy required for fiberization.

  From the above actions, the vacuum heat insulating material of the present invention improves the durability of the glass fiber used as the core material, so that not only the workability such as management during production can be improved, but also the thermal conductivity reduction effect of the glass material Therefore, the heat insulation performance is improved. In addition, productivity is improved.

  Further, if the alkaline earth metal oxide exceeds 15% by weight, the content of the alkali metal oxide in the composition in the vitrification range is limited. On the contrary, if the content of the alkaline earth metal oxide is less than 1% by weight, the durability is lowered. Therefore, these are preferably 1% by weight or more and 15% by weight or less.

  Invention of Claim 5 is a glass composition which consists of a composition range of the glass fiber of the vacuum heat insulating material as described in any one of Claims 1-4.

  Therefore, it is possible to obtain a glass having a low thermal conductivity that is transparent in the visible light region by reducing the thermal conductivity of the glass material and having durability.

  From the above effects, the glass composition of the present invention is not deteriorated over a long period of time, and a transparent heat insulating glass can be obtained in the visible light region, and the heat insulating effect is high in a car, a house, a showcase, etc. Space can be provided.

The invention according to claim 6 is the glass composition according to claim 5, wherein Fe ₂ O ₃ is contained in the range of 0.1 wt% or more and 5 wt% or less.

Therefore, by including Fe ₂ O ₃ in the glass component, light in the infrared light region is absorbed, so that radiation can be absorbed. Moreover, since this glass has a low thermal conductivity, it is very difficult to transmit the absorbed radiation as solid heat conduction.

  From the above effects, the glass composition of the present invention suppresses heat transfer due to radiation and improves the heat insulation performance of the glass. Further, when used as a core material for a vacuum heat insulating material, the heat insulating performance is similarly improved.

Moreover, it is preferable to manufacture glass using a natural material or a recycled cullet, and productivity can be improved by using glass containing about 0.1 wt% Fe ₂ O ₃ which is generally contained as an impurity. On the other hand, if it exceeds 5% by weight, the viscosity characteristics become high, so that the heat energy during production increases and the productivity decreases.

  The glass fiber that can be used in the present invention is not particularly limited, but is a glass-forming oxide that can be in a glass state. Further, when it is made into an aggregate, it is laminated uniformly in the thickness direction. Arranged ones are suitable, and glass wool is more preferable as a general-purpose industrial product from the viewpoint of low cost and handleability. However, long fibers may be processed into a mat shape.

  The fiber diameter is not particularly specified, but it is already known that a finer fiber diameter can provide better heat insulation performance. However, the heat insulation performance that could not be obtained with a core material using conventional glass wool can be realized with glass fibers having an average fiber diameter of 3 μm or more in this configuration. Excellent heat insulation performance can be realized at low cost without causing a decrease.

In addition, the glass that can be used in the present invention may be a fiber made of a glass-forming oxide that can be in a glass state. However, in consideration of general versatility and environmental aspects, a silicate system mainly containing SiO _2. Borosilicate glass is preferred.

In addition, when the glass cannot be vitrified stably with an increase in the content of alkali metal oxides or the like, a network-forming oxide or an intermediate oxide can be added. In order to improve the weather resistance, a small amount of B ₂ O ₃ may be added. In addition, when P ₂ O ₅ having the same low viscosity characteristic is added, biodegradability is increased and safety is increased.

  Moreover, it is preferable that the glass material is a natural material as a main raw material from the economical and environmental viewpoints, and variations due to impurities are unavoidable in the glass component, so that it may contain about 1% by weight other than the specific component. good.

  In addition, a plastic laminate film can be used as the outer packaging material of the present invention, but a metal foil or a vapor deposition layer can be applied in order to impart higher gas barrier properties. In addition, a metal foil and a vapor deposition layer can use a well-known thing, and it does not specify it in particular.

  Moreover, an adsorbent can be applied to the vacuum heat insulating material in the present invention to improve heat insulating performance and durability by reducing internal pressure. The adsorbing material that can be applied is not particularly limited as long as it adsorbs water vapor existing inside the vacuum heat insulating material and reduces the amount of water vapor in the internal atmosphere.

  Examples include physical adsorbents such as synthetic zeolite, activated carbon, activated alumina, silica gel, dosonite, and hydrotalcite, and chemical adsorbents such as alkali metals and alkaline earth metals alone and their oxides and hydroxides. It is.

  Furthermore, by using together a getter material that can adsorb an air component, it is possible to reduce the heat conduction of the internal gas component and improve the heat insulation performance.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 shows a cross-sectional view of a vacuum heat insulating material according to Embodiment 1 of the present invention.

  In FIG. 1, a vacuum heat insulating material 1 is configured by inserting a core material 2 and a moisture adsorbing material 3 into an outer packaging material 4 and reducing the pressure inside.

  The vacuum heat insulating material 1 is produced by drying the core material 2 in a drying furnace at 140 ° C. for 30 minutes, and then inserting the three sides of the laminate film into the outer packaging material 4 formed into a bag shape by heat sealing. Thus, the pressure is reduced so that the inside of the outer packaging material becomes 10 Pa or less, and the opening is hermetically sealed by heat welding.

  At this time, the outer packaging material 4 is composed of a laminate film composed of a polyethylene terephthalate film (12 μm) as a surface protective layer, an aluminum foil (6 μm) as an intermediate layer, and a linear low-density polyethylene film (50 μm) as a heat welding layer. ing.

  In addition, calcium oxide is applied as the moisture adsorbent 3. Although there is no particular problem even when the moisture adsorbing material 3 is not provided, the provision of the moisture adsorbing material not only can further reduce the possibility that glass fiber will be eroded by moisture by adsorbing the residual water vapor inside, but the end face. The increase in internal pressure due to water vapor intrusion from can be suppressed over a long period of time. Furthermore, by using a gas adsorbent in combination, the internal pressure can be further reduced and the heat insulation performance can be improved.

On the other hand, the core material 2 is a board-shaped member that is heated in a pressurized state with a glass fiber aggregate having an average fiber diameter of 3.5 μm and that maintains a shape with a density of about 200 kg / m ³ . Further, the core portion density after sealing in terms of thermal insulation performance and handling properties is preferably in the range of 210~280kg / m ^3, was made as a 240 kg / m ^3.

  Here, the core material is formed without using the binder, but the core material may be formed at a lower temperature using the binder. If the surface property does not matter, the glass fiber aggregate may be hermetically sealed as it is. In that case, since the number of manufacturing steps is reduced, productivity is improved.

  In addition, the glass composition used and the specific contents of the glass physical properties will be described in detail in the examples. As the glass physical properties, the thermal conductivity, durability, and softening point of the glass material are measured. The thermal conductivity of the vacuum heat insulating material 1 using a glass fiber as a core material was measured. Here, the glass fiber material means the glass itself forming the fiber.

  The thermal conductivity measurement method includes a steady method and an unsteady method, but this time, as an example, using a glass fiber having the same composition which has been remelted and formed into a sheet glass shape, an average is obtained by the unsteady hot wire method. The thermal conductivity around 30 ° C. was calculated.

  As for durability, glass fibers are immersed in distilled water at 96 ° C., and the weight loss rate after one week is used as an index, so that the durability is sufficient as a core material of a vacuum heat insulating material by being 10% by weight or less. Judged to prepare.

The softening point was determined as the temperature when the viscosity was 10 ^7.65 dPa · s by clarifying the relationship between temperature and viscosity by the penetration method. Furthermore, about the composition of glass, it displays by the weight ratio by the fluorescent X ray analysis after shaping | molding about each of plate glass and glass fiber.

  The thermal conductivity of the vacuum heat insulating material 1 formed as described above was measured with an auto lambda manufactured by Eihiro Seiki. As a result, the thermal conductivity is 0.0009 to 0.0016 W / mK at an average temperature of 24 ° C., more than 10 times that of a general-purpose hard urethane foam, and nearly twice that of a conventional vacuum heat insulating material. It had heat insulation performance.

That is, according to the fluorescent X-ray analysis, the heat insulation performance is good with respect to a composition in which the total amount of alkali metal oxides such as Na ₂ O and K ₂ O is in the range of 20 to 40% in the glass fiber composition. Also, it showed excellent characteristics in terms of viscosity characteristics. Further, the durability of glass fibers having a composition in this range was not particularly problematic.

  Thus, the vacuum heat insulating material 1 produced by this structure has the outstanding heat insulation performance. This is because, in the glass fiber assembly used for the core material 2, the solid heat conduction of the glass itself has been reduced, so that the solid component in the core material portion that has conventionally occupied most of the heat transfer elements of the vacuum heat insulating material. Therefore, the heat insulation performance of the vacuum heat insulating material can be improved.

Moreover, in this embodiment, the one containing B ₂ O ₃ or Al ₂ O ₃ is used. As a result, water resistance, handleability, and glass formability functionality are imparted. Therefore, in addition to the structure of the present invention, it is preferable to add an appropriate amount thereof, but if the amount is large, the thermal conductivity increases. It is preferably 5% by weight or less.

  Furthermore, the glass according to the present invention has a low thermal conductivity of the material and is useful as a heat insulating glass plate as it is. In other words, even glass used in places such as automobiles and house windows has a low thermal conductivity, so that it is possible to make the space highly heat-insulating and have a high thermal insulation effect.

  Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited only to the Examples.

Example 1
By weight, SiO ₂ is 65.2%, Al ₂ O ₃ is 1.0%, B ₂ O ₃ is 3.0%, Na ₂ O is 14.0%, K ₂ O is 1.2%, Cs ₂ O is 4.8%, MgO is 2.0%, CaO is 7.0%, Fe ₂ O ₃ is 0.3%, TiO ₂ is 0.1%, and other impurities are 1.4%. A glass material having a glass composition was prepared, and the thermal conductivity, durability, and softening point of the glass material were measured.

  As a result, the thermal conductivity at 35 ° C. of the glass material was 0.88 W / mK, indicating a lower thermal conductivity than the conventional glass material for core material. As for durability, the weight loss rate was 4.0%, and there was no problem as a glass fiber core material for plate glass and vacuum heat insulating material. Moreover, about the softening point, it was 701 degreeC and the low-viscosity characteristic was shown rather than the conventional glass composition for general purpose glass fibers.

  Therefore, it can be said that the glass material has more excellent glass properties than those shown in the comparative examples.

  Moreover, when a vacuum heat insulating material was produced using the glass fiber made of this glass material as a core material and the thermal conductivity was measured, it was 0.0015 W / mK at an average temperature of 24 ° C.

Therefore, the vacuum heat insulating material of this example has excellent heat insulating performance when the glass fiber of the core material contains 20% by weight of alkali metal oxides in total and 0.1% of TiO ₂ .

Furthermore, by using Cs ₂ O as the alkali metal oxide, the effect of reducing the thermal conductivity can be obtained even with a small amount of alkali metal oxide.

(Example 2)
By weight, SiO ₂ is 50.2%, Al ₂ O ₃ is 0.8%, B ₂ O ₃ is 3.2%, Na ₂ O is 27.5%, K ₂ O is 2.5%, A glass material having a glass composition composed of a large number of impurities of 1.0% MgO, 3.0% CaO, 0.2% Fe ₂ O, 10% TiO ₂ , and 1.6% is also produced. The thermal conductivity, durability, and softening point were measured.

  As a result, the thermal conductivity at 35 ° C. of the glass material was 0.58 W / mK, indicating a lower thermal conductivity than the conventional one. As for durability, the weight loss rate was 5.5%, and there was no problem as a glass fiber core material for plate glass and vacuum heat insulating material. Moreover, about the softening point, it was 692 degreeC and the low-viscosity characteristic was shown rather than the conventional glass composition for general purpose glass fibers.

  Therefore, it can be said that the glass material has more excellent glass properties than those shown in the comparative examples.

  Moreover, when a vacuum heat insulating material was produced using the glass fiber made of this glass material as a core material and the thermal conductivity was measured, it was 0.0013 W / mK at an average temperature of 24 ° C.

Therefore, the vacuum heat insulating material of this example has excellent heat insulating performance when the glass fiber of the core material contains 30% by weight of alkali metal oxides in total and 10% of TiO ₂ .

(Example 3)
By weight ratio, SiO ₂ is 31.9%, Al ₂ O ₃ is 0.5%, B ₂ O ₃ is 4.5%, Na ₂ O is 35.0%, K ₂ O is 5.0%, A glass material having a glass composition composed of 1.5% MgO, 0.5% CaO, 0.1% Fe ₂ O, 20% TiO ₂ , and 2.2% of other impurities is produced. The thermal conductivity, durability, and softening point were measured.

  As a result, the thermal conductivity at 34 ° C. of the glass material was 0.21 W / mK, indicating a lower thermal conductivity than the conventional one. As for durability, the weight loss rate was 7.6%, and there was no problem as a glass fiber core material for plate glass and vacuum heat insulating material. Moreover, about the softening point, it was 668 degreeC and the low-viscosity characteristic was shown rather than the conventional glass composition for general purpose glass fibers.

  Therefore, it can be said that the glass material has more excellent glass properties than those shown in the comparative examples.

  Moreover, when a vacuum heat insulating material was produced using the glass fiber made of this glass material as a core material and the thermal conductivity was measured, it was 0.0009 W / mK at an average temperature of 24 ° C.

Therefore, the vacuum heat insulating material of this example has excellent heat insulating performance when the glass fiber of the core material contains 40% by weight of alkali metal oxides in total and 20% of TiO ₂ .

Example 4
By weight, SiO ₂ is 61.1%, Al ₂ O ₃ is 1.2%, B ₂ O ₃ is 7.1%, Na ₂ O is 18.1%, K ₂ O is 1.9%, A glass material having a glass composition composed of a large number of impurities of 2.1% for MgO, 6.4% for CaO, 0.3% for Fe ₂ O ₃ , 0.1% for ZrO ₂ , and 1.7% for others, The thermal conductivity, durability, and softening point of the glass material were measured.

  As a result, the thermal conductivity at 36 ° C. of the glass material was 0.69 W / mK, indicating a lower thermal conductivity than the conventional one. As for durability, the weight loss rate was 5.8%, and there was no problem as a glass fiber core material for plate glass and vacuum heat insulating material. Moreover, about the softening point, it was 698 degreeC and the low-viscosity characteristic was shown rather than the conventional glass composition for general purpose glass fibers.

  Therefore, it can be said that the glass material has more excellent glass properties than those shown in the comparative examples.

  Moreover, when a vacuum heat insulating material was produced using the glass fiber made of this glass material as a core material and the thermal conductivity was measured, it was 0.0016 W / mK at an average temperature of 24 ° C.

Therefore, the vacuum heat insulating material of this example has excellent heat insulating performance when the glass fiber of the core material contains 20% by weight of the total amount of alkali metal oxides and 0.1% by weight of ZrO ₂ .

(Example 5)
By weight, SiO ₂ is 46.0%, Al ₂ O ₃ is 1.0%, B ₂ O ₃ is 5.4%, Na ₂ O is 28.0%, K ₂ O is 2.8%, A glass material having a glass composition comprising 1.7% of MgO, 3.2% of CaO, 0.3% of Fe ₂ O ₃ , 10% of ZrO ₂ , and 1.6% of other impurities is produced. The thermal conductivity, durability, and softening point of the material were measured.

  As a result, the thermal conductivity of the glass material at 34 ° C. was 0.46 W / mK, indicating a lower thermal conductivity than the conventional one. As for durability, the weight loss rate was 2.6%, and there was no problem as a glass fiber core material for plate glass and vacuum heat insulating material. Moreover, about the softening point, it was 738 degreeC and the low-viscosity characteristic was shown rather than the conventional glass composition for general purpose glass fibers.

  Therefore, it can be said that the glass material has more excellent glass properties than those shown in the comparative examples.

  Moreover, when a vacuum heat insulating material was produced using the glass fiber made of this glass material as a core material and the thermal conductivity was measured, it was 0.0012 W / mK at an average temperature of 24 ° C.

Therefore, the vacuum heat insulating material of this example has excellent heat insulating performance when the glass fiber of the core material contains 30.8% by weight of alkali metal oxide and 10% by weight of ZrO ₂ .

(Example 6)
By weight, SiO ₂ is 30.9%, Al ₂ O ₃ is 1.0%, B ₂ O ₃ is 3.3%, Na ₂ O is 35.1%, K ₂ O is 4.9%, A glass material having a glass composition composed of 2.0% MgO, 0.3% CaO, 0.2% Fe ₂ O ₃ , 20% ZrO ₂ , and 2.3% of other impurities is produced. The thermal conductivity, durability, and softening point of the material were measured.

  As a result, the thermal conductivity at 34 ° C. of the glass material was 0.33 W / mK, indicating a lower thermal conductivity than the conventional one. As for durability, the weight loss rate was 1.1%, and there was no problem as a glass fiber core material for plate glass and vacuum heat insulating material. Moreover, about the softening point, it was 783 degreeC and the viscosity characteristic a little higher than the conventional glass composition for general purpose glass fibers was shown.

  Therefore, it can be said that the glass material has better heat insulation than that shown in the comparative example.

  Moreover, when a vacuum heat insulating material was produced using the glass fiber made of this glass material as a core material and the thermal conductivity was measured, it was 0.0011 W / mK at an average temperature of 24 ° C.

Therefore, the vacuum heat insulating material of this example has excellent heat insulating performance when the glass fiber of the core material contains 40% by weight of alkali metal oxide and 20% by weight of ZrO ₂ .

(Example 7)
By weight, SiO ₂ is 53.0%, Al ₂ O ₃ is 1.2%, B ₂ O ₃ is 5.0%, Na ₂ O is 30.1%, K ₂ O is 0.7%, A glass material having a glass composition composed of 1.9% MgO, 0.4% CaO, 0.3% Fe ₂ O ₃ , 0.1% ZnO, and 2.1% other impurities is produced. The thermal conductivity, durability, and softening point of the glass material were measured.

  As a result, the thermal conductivity at 35 ° C. of the glass material was 0.68 W / mK, indicating a lower thermal conductivity than the conventional one. As for durability, the weight loss rate was 5.5%, and there was no problem as a glass fiber core material for plate glass and vacuum heat insulating material. Moreover, about the softening point, it was 704 degreeC and the low-viscosity characteristic was shown rather than the conventional glass composition for general purpose glass fibers.

  Therefore, it can be said that the glass material has more excellent glass properties than those shown in the comparative examples.

  Moreover, when a vacuum heat insulating material was produced using the glass fiber made of this glass material as a core material and the thermal conductivity was measured, it was 0.0016 W / mK at an average temperature of 24 ° C.

  Therefore, the vacuum heat insulating material of this example has excellent heat insulating performance when the glass fiber of the core material contains 30.8% by weight of alkali metal oxide and 0.1% by weight of ZnO.

(Example 8)
By weight, SiO ₂ is 38.7%, Al ₂ O ₃ is 1.1%, B ₂ O ₃ is 4.9%, Na ₂ O is 30.0%, K ₂ O is 0.6%, A glass material having a glass composition composed of 1.5% MgO, 0.7% CaO, 0.3% Fe ₂ O ₃ , 20% ZnO, and 2.2% of other impurities is produced. The thermal conductivity, durability, and softening point were measured.

  As a result, the thermal conductivity at 35 ° C. of the glass material was 0.56 W / mK, indicating a lower thermal conductivity than the conventional one. As for durability, the weight loss rate was 5.7%, and there was no problem as a glass fiber core material for plate glass and vacuum heat insulating material. Moreover, about the softening point, it was 681 degreeC and the low-viscosity characteristic was shown rather than the conventional glass composition for general purpose glass fibers.

  Therefore, it can be said that the glass material has more excellent glass properties than those shown in the comparative examples.

  Moreover, when a vacuum heat insulating material was produced using the glass fiber made of this glass material as a core material and the thermal conductivity was measured, it was 0.0013 W / mK at an average temperature of 24 ° C.

  Therefore, the vacuum heat insulating material of this example has excellent heat insulating performance when the glass fiber of the core material contains 30.6% by weight of alkali metal oxide and 20% by weight of ZnO.

Example 9
By weight ratio, SiO ₂ is 33.0%, Al ₂ O ₃ is 0.8%, B ₂ O ₃ is 1.2%, Na ₂ O is 30.0%, K ₂ O is 0.6%, A glass material having a glass composition composed of 1.6% MgO, 0.6% CaO, 0.2% Fe ₂ O ₃ , 30.0% ZnO, and 2.0% other impurities is produced. The thermal conductivity, durability, and softening point of the glass material were measured.

  As a result, the thermal conductivity of the glass material at 24 ° C. was 0.35 W / mK, which was lower than that of the conventional material. As for durability, the weight loss rate was 5.0%, and there was no problem as a core material of the vacuum heat insulating material. Moreover, about the softening point, it was 675 degreeC, and the low-viscosity characteristic was shown rather than the glass composition for the conventional general purpose glass fiber.

  Therefore, it can be said that the glass physical property which was excellent as a glass material for core materials of a vacuum heat insulating material is shown rather than what is shown in a comparative example. Furthermore, the glass fiber containing ZnO is particularly excellent in durability, and is useful for improving productivity from the viewpoint of easy water management and the like.

  Moreover, when a vacuum heat insulating material was produced using the glass fiber made of this glass material as a core material and the thermal conductivity was measured, it was 0.0011 W / mK at an average temperature of 24 ° C.

  Therefore, the vacuum heat insulating material of the present example has excellent heat insulating performance when the glass fiber of the core material contains 30.6% by weight of alkali metal oxide and 30% by weight of ZnO.

(Example 10)
By weight ratio, SiO ₂ is 46.7%, Al ₂ O ₃ is 1.2%, B ₂ O ₃ is 5.0%, Na ₂ O is 30.1%, K ₂ O is 0.7%, Glass composed of a large number of impurities of MgO 1.9%, CaO 2.0%, BaO 5.2%, Fe ₂ O ₃ 0.1%, TiO ₂ 5.0%, and other 2.1%. A glass material having a composition was prepared, and the thermal conductivity, durability, and softening point of the glass material were measured.

  As a result, the thermal conductivity at 35 ° C. of the glass material was 0.55 W / mK, indicating a lower thermal conductivity than the conventional one. As for durability, the weight loss rate was 5.0%, and there was no problem as a glass fiber core material for plate glass and vacuum heat insulating material. Moreover, about the softening point, it was 686 degreeC and the low-viscosity characteristic was shown rather than the conventional glass composition for general purpose glass fibers.

  Therefore, it can be said that the glass material has more excellent glass properties than those shown in the comparative examples.

  Moreover, when a vacuum heat insulating material was produced using the glass fiber made of this glass material as a core material and the thermal conductivity was measured, it was 0.0015 W / mK at an average temperature of 24 ° C.

Therefore, the vacuum heat insulating material of this example has excellent heat insulating performance when the glass fiber of the core material contains 30.8% by weight of alkali metal oxide and 0.1% by weight of Fe ₂ O _3. Yes.

(Example 11)
By weight ratio, SiO ₂ is 47.7%, Al ₂ O ₃ is 1.1%, B ₂ O ₃ is 4.9%, Na ₂ O is 30.0%, K ₂ O is 0.6%, Create a glass material with a glass composition consisting of a large number of impurities of 1.5% MgO, 4.7% CaO, 2.2% Fe ₂ O ₃ , 5.1% TiO ₂ and 2.2% other The thermal conductivity, durability, and softening point of the glass material were measured.

  As a result, the thermal conductivity at 35 ° C. of the glass material was 0.44 W / mK, indicating a lower thermal conductivity than the conventional one. As for durability, the weight loss rate was 5.3%, and there was no problem as a glass fiber core material for plate glass and vacuum heat insulating material. Moreover, about the softening point, it was 711 degreeC and the low-viscosity characteristic was shown rather than the conventional glass composition for general purpose glass fibers.

  Therefore, it can be said that the glass material has more excellent glass properties than those shown in the comparative examples.

  Moreover, when a vacuum heat insulating material was produced using the glass fiber made of this glass material as a core material and the thermal conductivity was measured, it was 0.0014 W / mK at an average temperature of 24 ° C.

Therefore, the vacuum heat insulating material of this example has excellent heat insulating performance when the glass fiber of the core material contains 30.6% by weight of alkali metal oxide and 2.2% by weight of Fe ₂ O _3. Yes.

(Example 12)
By weight, SiO ₂ is 49.3%, Al ₂ O ₃ is 0.8%, B ₂ O ₃ is 1.2%, Na ₂ O is 30.0%, K ₂ O is 0.6%, MgO is 1.6% CaO is 4.6% Fe ₂ O ₃ is 5.0% TiO ₂ is 4.9%, making a glass material of the glass composition composed of other 2.0% of the number impurities, The thermal conductivity, durability, and softening point of the glass material were measured.

  As a result, the thermal conductivity at 35 ° C. of the glass material was 0.40 W / mK, indicating a lower thermal conductivity than the conventional one. As for durability, the weight loss rate was 5.0%, and there was no problem as a glass fiber core material for plate glass and vacuum heat insulating material. Moreover, about the softening point, it was 765 degreeC, and the low-viscosity characteristic was shown rather than the conventional glass composition for general purpose glass fibers.

  Therefore, it can be said that the glass material has more excellent glass properties than those shown in the comparative examples.

  Moreover, when a vacuum heat insulating material was produced using the glass fiber made of this glass material as a core material and the thermal conductivity was measured, it was 0.0013 W / mK at an average temperature of 24 ° C.

Therefore, the vacuum heat insulating material of this example has excellent heat insulating performance when the glass fiber of the core material contains 30.8% by weight of alkali metal oxide and 0.1% by weight of Fe ₂ O _3. Yes.

(Comparative Example 1)
By weight, SiO ₂ 61.3%, Al ₂ O ₃ 2.2%, B ₂ O ₃ 4.0%, Na ₂ O 16.4%, K ₂ O 1.3%, A glass material for general purpose glass wool having a glass composition comprising 3.0% MgO, 8.7% CaO, 0.7% Fe ₂ O, 0.7% TiO ₂ and 1.7% other impurities. Used to measure the thermal conductivity, durability, and softening point of the glass material.

  As a result, the thermal conductivity of the glass material at 24 ° C. was 1.04 W / mK. Durability was a good value because the weight loss rate was 4.0% and it was a normal product for heat insulating heat. The softening point was 735 ° C.

  Moreover, when a vacuum heat insulating material was produced using the glass fiber made of this glass material as a core material and the thermal conductivity was measured, it was 0.0020 W / mK at an average temperature of 24 ° C.

(Comparative Example 2)
By weight, SiO ₂ is 32.0%, Al ₂ O ₃ is 1.0%, B ₂ O ₃ is 5.0%, Na ₂ O is 39.6%, K ₂ O is 3.6%, A glass material having a glass composition composed of 1.5% MgO, 5.0% CaO, 0.3% Fe ₂ O ₃ , 2.0% ZnO, and 2.0% other impurities, The thermal conductivity, durability, and softening point of the glass material were measured.

  As a result, the thermal conductivity of the glass material at 35 ° C. is 0.36 W / mK, and the thermal conductivity of the glass material is lower than that of the conventional material, but the alkali metal oxide of this comparative example contains more than 40% by weight. The glass fiber has a weight loss rate of 15.4%, and is particularly apt to be eroded by moisture. Moreover, about the softening point, it was 676 degreeC, and the low-viscosity characteristic was shown rather than the glass composition for the conventional general purpose glass fiber.

  Therefore, although it shows the characteristic excellent in heat conductivity and a viscosity characteristic as a glass material for core materials of a vacuum heat insulating material rather than what is shown in an Example, it can be said that there exists a problem by low durability.

(Comparative Example 3)
By weight, SiO ₂ is 31.5%, Al ₂ O ₃ is 3.5%, B ₂ O ₃ is 4.6%, Na ₂ O is 25.8%, K ₂ O is 0.7%, As a result of producing a plate glass having a glass composition comprising 3.7% MgO, 4.9% CaO, 0.1% Fe ₂ O _{3 and} 25.1% TiO ₂ , the glass composition was devitrified. The quality was poor.

Therefore, it is desirable that TiO ₂ is 20% by weight or less.

(Comparative Example 4)
In terms of weight ratio, SiO ₂ is 35.1%, Al ₂ O ₃ is 2.2%, B ₂ O ₃ is 6.4%, Na ₂ O is 25.0%, K ₂ O is 0.4%, As a result of producing a plate glass having a glass composition comprising 2.7% MgO, 4.1% CaO, 0.1% Fe ₂ O _{3 and} 23.8% ZrO ₂ , the glass composition was devitrified. The quality was poor.

Therefore, ZrO ₂ is desirably 20% by weight or less.

(Comparative Example 5)
By weight, SiO ₂ is 54.1%, Al ₂ O ₃ is 1.0%, B ₂ O ₃ is 4.0%, Na ₂ O is 24.7%, K ₂ O is 0.8%, A glass sheet having a glass composition comprising 2.2% MgO, 5.0% CaO, 8.0% Fe ₂ O, 0.1% TiO _{2 and} 0.1% by weight ZnO was prepared. The material was measured for thermal conductivity, durability, and softening temperature.

  As a result, the thermal conductivity of the glass material at 35 ° C. was 1.01 W / mK. The durability is as good as 2.0% by weight loss. Moreover, about a softening point, it is 821 degreeC, and the thermal energy at the time of fiberization increases.

  The results of Examples 1 to 12 and Comparative Examples 1 to 5 are summarized in (Table 1).

  The vacuum heat insulating material according to the present invention has a heat insulating performance superior to that of the conventional heat insulating material because it can reduce the thermal conductivity of the glass material used for the core material and can significantly reduce the heat conduction of the solid component. The heat energy at the time of manufacture can be greatly reduced.

  As a result, it can be used for equipment that requires heat insulation, such as refrigerators and refrigerators, and is used for all types of heat insulation, heat shielding applications, heat damage countermeasures, etc. This can contribute to energy saving. Furthermore, if it is used with a single glass, a transparent and highly heat-insulating space can be provided.

  In addition, the vacuum heat insulating material in this invention can be applied to various apparatuses, from -30 ° C. which is an operating temperature zone of a refrigerator-freezer, a refrigeration apparatus, a vegetable cooler, a rice cooler, etc. Parts that require heat insulation, such as electricity, gas appliances and building materials for ordinary houses, etc. that use hot and cold heat in the range up to higher temperatures, such as machines, hot water tanks, etc. It can be applied to those including

Sectional drawing of the vacuum heat insulating material in Embodiment 1 of this invention

Explanation of symbols

1 Vacuum insulation material 2 Core material 4 Outer packaging material

Claims (6)

A core material made of glass fiber and an outer packaging material having a gas barrier property that covers the core material, wherein the inside of the outer packaging material is sealed under reduced pressure, and the glass fiber has at least one kind of alkali in the glass composition. It contains metal oxides in the range of 20 wt% or more and 40 wt% or less in total, and contains TiO ₂ in the range of 0.1 wt% or more and 20 wt% or less, and the thermal conductivity of the glass fiber material Is a vacuum heat insulating material having 1 W / mK or less. A core material made of glass fiber and an outer packaging material having a gas barrier property that covers the core material, wherein the inside of the outer packaging material is sealed under reduced pressure, and the glass fiber has at least one kind of alkali in the glass composition. Metal oxide is included in the range of 20 wt% or more and 40 wt% or less in total, and ZrO ₂ is included in the range of 0.1 wt% or more and 20 wt% or less, and the thermal conductivity of the glass fiber material Is a vacuum heat insulating material having 1 W / mK or less.   A core material made of glass fiber and an outer packaging material having a gas barrier property that covers the core material, wherein the inside of the outer packaging material is sealed under reduced pressure, and the glass fiber has at least one kind of alkali in the glass composition. Metal oxide is included in the range of 20 wt% or more and 40 wt% or less in total, and ZnO is included in the range of 0.1 wt% or more and 30 wt% or less, and the thermal conductivity of the glass fiber material is Vacuum insulation material that is 1 W / mK or less.   The vacuum heat insulating material as described in any one of Claims 1-3 containing an alkaline-earth metal oxide in 0.1 weight% or more and 15 weight% or less.   The glass composition which consists of a composition range of the glass fiber of the vacuum heat insulating material as described in any one of Claims 1-4. The glass composition according to claim 5, wherein Fe ₂ O ₃ is contained in the range of 0.1 wt% or more and 5 wt% or less.

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