JP2008057745A - Vacuum heat insulation material and glass composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve heat insulation performance, by reducing heat conduction of a solid component in a core material part, by restraining high density of a core material by atmospheric compression and an increase in a fiber contact part, by enhancing raw material strength of glass fiber used for the core material of a vacuum heat insulation material. <P>SOLUTION: This vacuum heat insulation material 1 is formed by sealing the inside of an external capsule material 4 by reducing pressure, by covering the core material 2 composed of the glass fiber and a moisture absorbing material 3 with the external capsule material 4 having gas-barrier performance. The glass fiber is alkali silicic acid glass, and is composed of composition including at least any one component among ZrO<SB>2</SB>, ZnO and TiO<SB>2</SB>, and including the total of ZrO<SB>2</SB>, ZnO and TiO<SB>2</SB>within a range of 0.5 to 13 wt.%. <P>COPYRIGHT: (C)2008,JPO&INPIT

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, application of 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 of solid and gas components. 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. Therefore, various fiber materials have been reported as a core material for vacuum heat insulating materials having excellent heat insulating performance.

  For example, glass fibers, ceramic fibers, slag wool fibers, rock wool fibers, etc. are used for the core material, and the average fiber length is 1 mm or less, the average fiber diameter is 0.5 to 3 μm, and the shape of the inorganic fibers is the direction of heat conduction. There has been proposed a vacuum heat insulating material oriented in the vertical direction with respect to (see, for example, Patent Document 1).

With this configuration, in the core material part of the vacuum heat insulating material, heat conduction of a single component is not performed so that heat is transmitted through one fiber in the heat transfer direction, but one after another through contact points between the fibers. Since heat is transferred to adjacent fibers, heat transfer is performed between the fibers in contact with each other in the heat transfer direction. Therefore, since the contact thermal resistance between the fibers exists, heat transfer in the core material portion is suppressed as compared with a core material in which one fiber directly transfers heat in the heat transfer direction. Furthermore, by controlling the fiber diameter and fiber length, it is possible to apply versatile inorganic fibers, and the thermal conductivity as a vacuum heat insulating material is stably set to 0.01 W / mK or less.
JP 7-167376 A

  However, the configuration of the conventional vacuum heat insulating material has versatility, and it has been impossible to further reduce the heat conduction of the solid component in the core portion of the vacuum heat insulating material.

  The present invention further describes a new design policy for reducing the heat conduction of the solid component in the core part.

  When the inorganic fiber is applied as the core material of the vacuum heat insulating material, the internal space is maintained in a state where the repulsive force of the entire fiber is balanced with the atmospheric compressive stress after the vacuum sealing. If the material strength of the fibers constituting this core material is improved, the core material can be made to have high resilience, and it is possible to maintain a space even with a lower density core material, which becomes a heat transfer medium. It is believed that solids can be reduced.

  In addition, since the core material has high resilience, the atmospheric compressive stress can be supported even with a smaller number of fiber contact points, and the contact area between the fibers due to the atmospheric compressive stress is crushed and the contact area can be increased. Can be suppressed.

  In other words, when using glass fiber with a low cost in terms of material and production as a core material, if the strength of the glass material can be increased, it has versatility and can further improve the heat insulating performance of the vacuum heat insulating material. Thought.

  In addition, when using ceramic fibers, it is possible to suppress the densification of the core material part even during air compression and increase the heat insulation performance because of high strength, but the material cost is high and the fibers Since the manufacturing cost for converting to a very high temperature is not preferable as a fiber used for a general-purpose heat insulating material.

  Moreover, in the case of using slag wool or rock wool, the heat insulation performance is further deteriorated compared to the case of using general-purpose glass fibers. This is more fragile than general-purpose glass fibers, and it is considered that the densification of the core material portion due to atmospheric compression, the number of fiber contacts and the contact area increase occur, and the heat insulating performance of the vacuum heat insulating material is lowered.

  The present invention solves the above-mentioned conventional problems, and as a core material of a vacuum heat insulating material, a core material by improving the strength of the glass material itself in a highly versatile glass fiber with low raw material and manufacturing costs. It aims at suppressing the heat transfer of a part and improving the heat insulation performance of a vacuum heat insulating material dramatically.

To achieve the above object, the vacuum heat insulator of the present invention, the glass fibers used in the core _material, ZrO 2, ZnO, of TiO _2, wherein at least any one component, and said _ZrO 2, ZnO, TiO The total of ₂ is% by weight and is characterized in that it is an alkali silicate glass having a composition contained within a range of 0.5 to 13%.

  As a result, the strength of the material itself in general-purpose glass can be increased, so when applied as a vacuum insulation core material, the amount of deformation of the core material due to atmospheric compressive stress after decompression sealing can be reduced and the density increased. Can be suppressed. Moreover, also in the contact part of each fiber used as the support part of a core material, the reduction | decrease of a contact point can be aimed at and the small deformation | transformation of glass means that the contact part area between fibers is small, and each fiber The amount of heat that travels between them can be reduced.

  The vacuum heat insulating material of the present invention can reduce the heat transfer amount between fibers in the core material part by suppressing the increase in density in the core material part and also suppressing the increase in the fiber contact part. Thereby, the heat conduction of the core solid component is reduced, and the heat insulating performance of the vacuum heat insulating material is dramatically improved. Therefore, since a high heat insulation effect is obtained by conventional production without changing the quality state such as fiber length, fiber diameter, and lamination state, the production is easy.

  Although the hardness and strength of the glass material in glass wool was originally a physical property that could be said to be irrelevant to the heat insulation performance, paying attention to the mechanical property of the material, heat insulation of the vacuum heat insulating material by making it a harder and stronger fiber It is a surprising fact that a performance improvement effect can be obtained.

Furthermore _ZrO 2, ZnO, TiO _2, these components reduce the thermal conductivity of the glass material by the addition of 0.5 to 13% by weight, suppressing heat conduction of the glass solid core portion. Therefore, the heat insulation performance of the core material portion can be synergistically improved by increasing the strength and reducing the thermal conductivity.

Moreover, since these glass fibers have higher mechanical strength than general-purpose glass wool, they are easy to handle and are useful as glass wool for general building materials and reinforcing materials. ZrO ₂ , ZnO, and TiO ₂ are all particularly effective when used as components of glass fibers that have a large surface area and are easily eroded because they all improve the water resistance of glass.

The invention of the vacuum heat insulating material according to claim 1 of the present invention is such that a core material made of glass fiber is covered with an outer packaging material having a gas barrier property, and the inside of the outer packaging material is hermetically sealed under reduced pressure. a silicate _glass, ZrO 2, ZnO, of TiO _2, wherein at least any one component, and said _ZrO 2, ZnO, the total of the TiO ₂ in weight percent, in the range of 0.5 to 13% It consists of the composition contained.

  Thereby, the material strength of the glass fiber can be increased, the densification of the core material due to the atmospheric compression stress can be suppressed, and the deformation amount of the glass fiber due to the atmospheric compression can be reduced, so that the increase in the contact area between the fibers can be suppressed. .

  By the above effect | action, the heat conduction of the solid component in the core material part of a vacuum heat insulating material is suppressed, and heat insulation performance improves. Furthermore, heat insulation performance can be improved synergistically by reducing the thermal conductivity of the glass material.

Moreover, the invention of the vacuum heat insulating material according to claim 2 of the present invention is such that the glass fiber in the invention according to claim 1 is by weight%, at least SiO ₂ is 50 to 70%, and Al ₂ O ₃ is 0 to 0. 7%, combined Na ₂ O and K ₂ O 8-20%, MgO 0-6%, CaO 2-15%, and the total weight percent of these components is 100% It is composed of a composition that does not exceed.

  Thereby, in addition to the effect | action of Claim 1, since it is close to common glass materials, such as plate glass, it is also possible to use commercial cullet etc., and a material is cheap and easy to acquire. With the above operation, the manufacturing cost can be reduced and the versatility is further increased.

Moreover, the invention of the vacuum heat insulating material according to claim 3 of the present invention is such that the glass fiber in the invention according to claim 1 or 2 is in% by weight and B ₂ O ₃ is in the range of 0.1 to 12%. Is included.

  Thereby, the strength of the glass is further increased, and the density of the core material and the increase in the contact area between the fibers can be further suppressed.

By the above effect | action, the heat conduction of the solid component in the core part of a vacuum heat insulating material is suppressed, and heat insulation performance improves further. Further, by containing B ₂ O ₃ , the surface tension at the time of glass melting is lowered, and the resistance force at the time of spinning is lowered, so that productivity is improved.

  Moreover, invention of the glass composition as described in Claim 4 of this invention is a glass composition used for the vacuum heat insulating material as described in any one of Claims 1-3.

  Therefore, since these glasses have high material strength, the rigidity as a glass molded product increases.

  By the above effect | action, since the glass composition in this invention is high intensity | strength and heat conductivity is lower than the conventional plate glass composition, it becomes a glass product which is hard to break and has high heat insulation. In particular, it is useful as a general-purpose heat insulating material superior in mechanical strength than conventional products for glass wool applications.

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 versatility and environmental aspects, a silicate system mainly containing SiO _2. Borosilicate glass is preferred.

The glass material strength is greatly increased by containing ZrO ₂ even in a small amount in the weight% of each component. However, if it exceeds 12%, the liquidus temperature of the glass is extremely increased, and the glass is devitrified at the time of fiber formation. Becomes a problem, and it becomes difficult to stably produce glass fibers. Therefore, ZrO ₂ is preferably in the range of 0.5 to 12%, more preferably 1 to 11%.

  Although ZnO contains even a small amount, the strength of the glass material is increased and the meltability is further improved. However, since the liquidus temperature rises when it exceeds 8%, the range of 0.5 to 10% is good, and 1 to 8% The range of is more preferable. Further, the water resistance is greatly improved, and the effect of improving the weather resistance is particularly great as a fiber.

By including even a small amount of TiO ₂ , the strength of the glass material is greatly increased. However, if it exceeds 10%, crystal nuclei are easily formed, and devitrification becomes a problem at the time of production. Therefore, the range of 0.5 to 10% is good, and the range of 1 to 8% is more preferable. In addition, TiO ₂ has a large effect of reducing the material thermal conductivity of glass, and the effect of improving the heat insulating property of the vacuum heat insulating material from both sides of the material strength and the material thermal conductivity can be obtained.

Even when ZrO ₂ , ZnO, and TiO ₂ are included in two or three components at the same time, improvement in material strength can be expected in the same manner, but if the total exceeds 10%, the liquidus temperature rises and crystal nuclei are likely to be formed. From the problem of devitrification, the total content is preferably 0.5 to 13%, more preferably 1 to 13%.

If SiO ₂ decreases, the liquidus temperature rises, and if it increases, the viscosity decreases and productivity decreases, so the range of 50 to 70% is preferable, but the range of 52 to 68% is more preferable. .

If Al ₂ O ₃ increases, the liquidus temperature rises and the viscosity increases, and if not contained, the strength of the material decreases. Therefore, it is better to contain in the range of 0.1% to 7%, more preferably in the range of 0.5 to 5.5%.

Increase in B ₂ O ₃ causes an increase in material cost, and if not included, the strength of the material is lowered. Therefore, it is preferable to include B ₂ O ₃ in a range of 0.1 to 12%. More preferably, it is 1-12%, More preferably, it is the range of 5-12%.

When Na ₂ O and K ₂ O increase, the strength of the material decreases, and when it decreases too much, the melting temperature rises. Therefore, the combined range of Na ₂ O and K ₂ O ranges from 8 to 20% by weight. good. More preferably, it is 10 to 18% of range. Moreover, it is better that K ₂ O is 5% or less from the viewpoint of water resistance. However, if 0.1% or more is contained, the effect of reducing viscosity is large, and K ₂ O is 0.1% from the problem of material cost. It is better to be in the range of ~ 3.5%. The alkaline earth metal oxide may be mixed with other LiO ₂ or the like, and in this case, the material strength is further improved.

  When MgO is included, the liquid phase temperature is lowered and the material strength is improved when it is increased. However, if it exceeds 6%, the liquid phase temperature rises conversely, so the range of 0 to 6% is better, more preferably 2 It is in the range of ˜5%.

  CaO contains 2% or more to increase the strength of the glass material in the same manner as MgO. If it exceeds 15%, the liquidus temperature rises, so the range is 2 to 15%, more preferably 4 to 11%. .

  As other components, if the total is less than 3% by weight, there is almost no influence on the whole glass, and natural raw materials containing impurities can be used as raw materials.

In addition, it is publicly known that human body safety is increased by adding P ₂ O _5, and may be included within a range of 3% or less. In that case, the viscosity decreases and the productivity increases without lowering the Young's modulus.

In addition, when Fe ₂ O ₃ is included, it tends to be colored, but since it becomes possible to absorb radiant heat, when transparency in the visible light region does not matter, it is 0.3 to 5% by weight. Inclusion in the range improves heat insulation. Moreover, it is more preferable that it is 4% or less in terms of devitrification, and the range of 0.5 to 4% is still better.

Moreover, when manufacturing a glass, it is preferable to use a refining agent in order to improve foaming and improve productivity, and known materials such as Sb ₂ O ₃ can be applied.

  Moreover, a moisture adsorbent can be used for the vacuum heat insulating material of the present invention. The moisture adsorbing material 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 or the like 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.

  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.

  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 4 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, by providing the moisture adsorbing material 3, the internal residual water vapor is adsorbed and an increase in internal pressure due to water vapor intrusion from the end face 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 state where a glass fiber aggregate having an average fiber diameter of 3.5 μm is pressurized and maintains a shape with a density of about 200 kg / m ³ . An average fiber diameter in the range of 1 μm to 10 μm is preferable in terms of quality and productivity.

Further, the core part bulk density after sealing in terms of thermal insulation performance and handling properties is more preferably in the range of ^{200kg / m 3 ~280kg / m 3} , was made as a this range. The core material 2 part bulk density is calculated from the weight of the core material 2 alone and the size after sealing.

  Here, the core material 2 is molded without using a binder, but the core material 2 may be molded at a lower temperature using a 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.

  Further, the specific contents of the glass composition used will be described in detail in Examples, but the outer packaging material in which the glass in the present invention is laminated as glass wool after fiberization and produced as the core material 2 and then the inside is decompressed. 4 was sealed to obtain a vacuum heat insulating material 1.

  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 0.0014 W / mK to 0.0019 W / mK at an average temperature of 24 ° C., which is more than 10 times that of a general-purpose rigid urethane foam, greatly compared to conventional vacuum heat insulating materials. It had excellent heat insulation performance.

  Thus, the vacuum heat insulating material 1 produced by this structure has the outstanding heat insulation performance. It can be confirmed that the improvement of the heat insulation performance increases in the glass fiber aggregate used for the core material 2 as the strength of the glass itself increases. Therefore, the heat conduction of the solid component in the core material part that previously occupied the majority of the heat transfer elements of the vacuum heat insulating material can be suppressed by improving the strength of the glass material, and the heat insulating performance of the vacuum heat insulating material is greatly improved. is there.

  The relationship between the material strength and the heat insulation performance is clear from the evaluation result of Young's modulus as the strength of the glass material and the relationship between the bulk density of the core material of the vacuum heat insulating material and the heat conductivity of the vacuum heat insulating material. is there. In other words, by improving the material strength of the glass, the core material bulk density is reduced to reduce the heat transfer medium, the space can be retained after atmospheric compression even if there are few contact points between the fibers, and between the core fibers It is thought that the contact heat resistance is increased by preventing deformation of the contact point, and that the heat transfer amount of the solid component in the core material part is reduced due to these factors.

  Although the thermal conductivity of the glass material itself has also decreased, it can be said that the degree of influence is much higher when the strength of the material is improved, considering the range of reduction in the thermal conductivity of the vacuum heat insulating material.

  The strength of the glass material was evaluated by measuring Young's modulus of glass processed into a flat plate having a thickness of about 1 mm by a resonance method. Similarly, when obtaining the Young's modulus, it may be measured by another method such as a pulse propagation method, or another intensity index may be used.

  The thermal conductivity of the glass material was measured by an unsteady hot wire method (Shower Denko ShotermTM) using a plate glass of 50 × 700 × 15 tmm. In addition, the measurement may be performed by a laser flash method or the like.

Although Fe ₂ O ₃ is easy to be mixed as an impurity, it does not cause a problem in particular, and has an effect of absorbing radiant heat. Therefore, for applications in a temperature range of 50 ° C. or higher where radiation contributes greatly. Useful.

(Embodiment 2)
The glass composition in Embodiment 2 of this invention is demonstrated. Each glass composition was formed into a fiber state.

  The melt made of the glass composition of the present invention was fiberized so that the average fiber diameter was about 3.5 μm. The average fiber diameter is preferably in the range of 1 to 10 μm. If it is less than 1 μm, the cost of fiberization increases extremely, and if it exceeds 10 μm, there is a risk of discomfort due to rigid fibers during handling. Regarding the fiberizing step, continuous spinning may be used as long fibers, or flame method, centrifugal method, etc. may be used as short fibers, but glass wool was produced by a centrifugal method in consideration of productivity. A long fiber such as a chop strand mat or a roving cloth can be produced and then processed to be used as a heat insulating material.

The glass wool thus produced was trimmed to a size of 200 × 200 mm, compressed in the thickness direction, and the compression strength at the time of compression was measured until the density was 250 kg / m ³ .

As a result, the compressive strength of the glass wool made of the glass composition according to the present invention was 1020 hPa or more, indicating a higher compressive strength than the conventional general-purpose glass wool. This is because the strength of the glass material itself is increased by including 5 to 12% of the amount of B ₂ O ₃ in the glass component, and the strength of the entire glass wool is increased.

  Therefore, by using a glass composition having a higher material strength than conventional ones, the compressive strength of glass wool is increased, providing glass wool that is useful as a heat insulating material and a reinforcing material for building materials, and has good handleability and workability. it can.

  Moreover, since the glass composition of this invention is high intensity | strength and low heat conductivity compared with general plate glass, it is useful also as heat insulation plate glass.

  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)
In this example, SiO ₂ was 68.0%, Al ₂ O ₃ was 2.9%, B ₂ O ₃ was 4.1%, Na ₂ O was 14.3%, and K _{2 in} terms of% by weight of the glass composition. O is 0.9%, MgO is 2.0%, CaO is 6.8%, ZrO ₂ is 0.5%, Fe ₂ O ₃ is 0.1%, and the total of other components is 0.4%. Glass was produced, and the material Young's modulus was 77.2 GPa. The factor that the Young's modulus is improved as compared with Comparative Example 1 is due to the addition of ZrO ₃ . Moreover, the raw material thermal conductivity of this glass was 1.08 W / mK.

  When this glass was laminated after fiberization to obtain glass wool, the compressive strength was 1045 hPa.

Further, when the vacuum heat insulating material was produced using this glass wool as a core material, the bulk density of the core material portion was 245 kg / m ³ and the thermal conductivity was 0.0019 W / mK.

(Example 2)
In this example, SiO ₂ is 50.0%, B ₂ O ₃ is 4.9%, Na ₂ O is 15.5%, K ₂ O is 0.1%, and MgO is 3% by weight% of the glass composition. A glass composed of 0.7%, CaO 9.5%, ZrO ₂ 11.0%, Fe ₂ O ₃ 5.0%, and other components totaling 0.3%, and its material Young's modulus is It was 83.2 GPa and the material thermal conductivity was 0.95 W / mK.

  When this glass was laminated after fiberization to obtain glass wool, the compressive strength was 1195 hPa.

Further, when the vacuum heat insulating material was produced using this glass wool as a core material, the bulk density of the core material portion was 233 kg / m ³ and the thermal conductivity was 0.0014 W / mK. Furthermore, even at an average of 50 ° C., the same vacuum heat insulating material has thermal conductivity, and it is considered that radiation is suppressed by containing 5% of Fe ₂ O ₃ even on the high temperature side affected by radiation.

(Example 3)
In this example, SiO ₂ was 55.4%, Al ₂ O ₃ was 0.1%, B ₂ O ₃ was 1.0%, Na ₂ O was 16.4%, and K _{2 in} terms of% by weight of the glass composition. A glass composed of 3.5% O, 3.0% MgO, 8.0% CaO, 12% ZrO ₂ , 0.3 Fe ₂ O _{3 and} 0.3% of the total of other components is prepared. The material Young's modulus was 83.7 GPa and the material thermal conductivity was 0.94 W / mK.

  When this glass was laminated after fiberization to obtain glass wool, the compressive strength was 1230 hPa.

Further, when a vacuum heat insulating material was produced using this glass wool as a core material, the bulk density of the core material portion was 231 kg / m ³ and the thermal conductivity was 0.0014 W / mK.

Example 4
In this example, SiO ₂ was 64.6%, Al ₂ O ₃ was 6.0%, B ₂ O ₃ was 0.1%, Na ₂ O was 19.6%, and K ₂ , in terms of% by weight of the glass composition. A glass composed of 0.4% O, 6.0% MgO, 2.0% CaO, 0.5% ZnO, and a total of other components of 0.8% is produced, and the material Young's modulus is 77. 0.0 GPa and the material thermal conductivity was 1.08 W / mK.

  When this glass was laminated after fiberization to obtain glass wool, the compressive strength was 1040 hPa.

Further, when the vacuum heat insulating material was produced using this glass wool as a core material, the bulk density of the core material portion was 245 kg / m ³ and the thermal conductivity was 0.0019 W / mK.

(Example 5)
In this example, SiO ₂ is 57.3%, Al ₂ O ₃ is 1.7%, B ₂ O ₃ is 5.0%, Na ₂ O is 7.7%, and K _{2 in} terms of% by weight of the glass composition. A glass composed of 0.3% O, 4.5% MgO, 15.0% CaO, 8% ZnO, and a total of 0.5% of other components, and its material Young's modulus is 79.3 GPa. The material thermal conductivity was 0.99 W / mK.

  The compression strength when this glass was laminated after fiberization to form glass wool was 1075 hPa.

Further, when a vacuum heat insulating material was produced using this glass wool as a core material, the bulk density of the core material part was 240 kg / m ³ , and the thermal conductivity was 0.0017 W / mK.

In this example, the alkali metal oxides of Na ₂ O and K ₂ O were 8%, and the fiber was obtained without problems as in the other examples. However, when the alkali metal oxide was less than 8%, The viscosity at the time of melting increased extremely, and the productivity was greatly reduced due to the increase in melting temperature.

(Example 6)
In this example, SiO ₂ was 56.8%, Al ₂ O ₃ was 0.5%, B ₂ O ₃ was 4.0%, Na ₂ O was 7.9%, and K _{2 in} terms of% by weight of the glass composition. Glass made of 2.1% O, 5.0% MgO, 9.5% CaO, 10.0% ZnO, 4.0% Fe ₂ O _{3 and} 0.2% of the total of other components The material had a Young's modulus of 79.8 GPa and a material thermal conductivity of 0.96 W / mK.

  The compression strength when this glass was laminated after fiberization to form glass wool was 1090 hPa.

Further, when a vacuum heat insulating material was produced using this glass wool as a core material, the bulk density of the core material portion was 239 kg / m ³ and the thermal conductivity was 0.0017 W / mK.

(Example 7)
In this example, SiO ₂ is 70.0%, Al ₂ O ₃ is 3.2%, B ₂ O ₃ is 3.0%, Na ₂ O is 16.1%, and K _{2 in} terms of% by weight of the glass composition. A glass composed of 2.0% O, 4.0% CaO, 0.5% TiO ₂ , 0.5% Fe ₂ O ₃ , and a total of several other components of 0.7% is prepared. The Young's modulus was 77.0 GPa and the material thermal conductivity was 1.07 W / mK.

  When this glass was laminated after fiberization to obtain glass wool, the compressive strength was 1040 hPa.

Further, when a vacuum heat insulating material was produced using this glass wool as a core material, the bulk density of the core material portion was 246 kg / m ³ and the thermal conductivity was 0.0019 W / mK.

(Example 8)
In this example, SiO ₂ is 52.0%, Al ₂ O ₃ is 1.3%, B ₂ O ₃ is 4.8%, Na ₂ O is 10.0%, and K _{2 in} terms of% by weight of the glass composition. O is 5.0%, MgO is 4.0%, CaO is 9.9%, TiO ₂ is 8.0%, Fe ₂ O ₃ is 3.0%, and the total of other components is 2.0%. A glass was produced, and the material Young's modulus was 82.1 GPa and the material thermal conductivity was 0.94 W / mK.

  The compression strength when this glass was laminated after fiberization to form glass wool was 1160 hPa.

Further, when the vacuum heat insulating material was produced using this glass wool as a core material, the bulk density of the core material portion was 236 kg / m ³ and the thermal conductivity was 0.0015 W / mK.

Example 9
In this example, SiO ₂ is 53.9%, B ₂ O ₃ is 4.0%, Na ₂ O is 16.2%, MgO is 4.0%, and CaO is 7.4% by weight% of the glass composition. %, TiO ₂ is 10.0%, Fe ₂ O ₃ is 1.5%, and other components total 3.0%, and the material Young's modulus is 82.5 GPa and the material thermal conductivity is It was 0.91 W / mK.

  When this glass was laminated after fiberization to obtain glass wool, the compressive strength was 1165 hPa.

Further, when the vacuum heat insulating material was produced using this glass wool as a core material, the bulk density of the core material portion was 235 kg / m ³ and the thermal conductivity was 0.0015 W / mK.

(Example 10)
In this example, SiO ₂ is 54.5%, Al ₂ O ₃ is 7.0%, B ₂ O ₃ is 12.0%, Na ₂ O is 15.0%, K _{2 in} terms of% by weight of the glass composition. O is 0.8%, MgO is 3.0%, CaO is 6.0%, ZrO ₂ is 0.5%, TiO ₂ is 0.5%, Fe ₂ O ₃ is 0.2%, and other components. Glass with a total of 0.5% was produced, and the material Young's modulus was 81.7 GPa and the material thermal conductivity was 1.06 W / mK.

  When this glass was laminated after fiberization to obtain glass wool, the compressive strength was 1120 hPa.

Further, when the vacuum heat insulating material was produced using this glass wool as a core material, the bulk density of the core material portion was 238 kg / m ³ and the thermal conductivity was 0.0016 W / mK.

(Example 11)
In this example, SiO ₂ is 61.1%, Al ₂ O ₃ is 1.0%, Na ₂ O is 12.0%, K ₂ O is 0.9%, and MgO is 3% by weight% of the glass composition. .3%, CaO 6.9%, ZrO ₂ 5.0%, ZnO 3.0%, TiO ₂ 5.0%, Fe ₂ O ₃ 1.0%, and other components total 0 A glass composed of 0.8% was produced, and the material Young's modulus was 82.6 GPa and the material thermal conductivity was 0.90 W / mK.

  When this glass was laminated after fiberization to obtain glass wool, the compressive strength was 1180 hPa.

Further, when a vacuum heat insulating material was produced using this glass wool as a core material, the bulk density of the core material part was 235 kg / m ³ and the thermal conductivity was 0.0014 W / mK.

(Comparative Example 1)
This comparative example is a general glass wool, in which the SiO ₂ is 64.6%, Al ₂ O ₃ is 1.7%, B ₂ O ₃ is 4.0%, and Na ₂ O is 5% by weight of the glass composition. 14.5%, K ₂ O 0.8%, MgO 3.8%, CaO 10.0%, TiO ₂ 0.1%, Fe ₂ O ₃ 0.1%, and other multiple components total Of 0.4% was produced, and the material Young's modulus was 75.0 GPa and the material thermal conductivity was 1.08 W / mK.

  When this glass was laminated after fiberization to obtain glass wool, the compressive strength was 1010 hPa.

Further, when a vacuum heat insulating material was produced using this glass wool as a core material, the bulk density of the core material portion was 250 kg / m ³ and the thermal conductivity was 0.0022 W / mK.

(Comparative Example 2)
In this comparative example, SiO ₂ is 57.8%, Al ₂ O ₃ is 0.1%, B ₂ O ₃ is 4.2%, Na ₂ O is 13.5%, and K 2 ₂ O is 0.7% MgO is 3.5% CaO is 6.3% ZrO ₂ is 14% _Fe 2 _{O 3} is 0.1%, glass and other multi-component sum is a 0.8% The material Young's modulus was 88.5 GPa and the material thermal conductivity was 0.92 W / mK.

Further, since this glass contains 14% of ZrO ₂ , the liquidus temperature was extremely increased, and the glass was devitrified during fiberization, so that it could not be fiberized.

(Comparative Example 3)
In this comparative example, SiO ₂ is 60.5%, Al ₂ O ₃ is 0.9%, B ₂ O ₃ is 4.8%, Na ₂ O is 16.2%, and K _{2 in} terms of% by weight of the glass composition. A glass composed of 0.2% O, 2.0% MgO, 4.1% CaO, 14% ZnO, 0.2% Fe ₂ O _{3 and a} total of other components of 0.1% is prepared. The material Young's modulus was 80.5 GPa, and the material thermal conductivity was 0.95 W / mK.

  Further, since this glass contains 14% of ZnO, the liquidus temperature rises, and it becomes devitrified at the time of fiberization, so that it cannot be fiberized.

(Comparative Example 4)
In this comparative example, SiO ₂ was 60.1%, Al ₂ O ₃ was 2.1%, B ₂ O ₃ was 3.6%, Na ₂ O was 15.3%, and K _{2 in} terms of% by weight of the glass composition. A glass composed of 0.7% O, 1.2% MgO, 5.0% CaO, 14% TiO ₂ , 0.2% Fe ₂ O ₃ , and a total of other components of 0.8%. The material Young's modulus was 87.0 GPa and the material thermal conductivity was 0.90 W / mK.

Further, since this glass contains 14% of TiO ₂ , the liquidus temperature rises and the glass becomes devitrified at the time of fiberization, so that it cannot be fiberized.

(Comparative Example 5)
In this comparative example, SiO ₂ is 56.6%, Al ₂ O ₃ is 2.0%, B ₂ O ₃ is 4.1%, Na ₂ O is 16.0%, and K _{2 in} terms of% by weight of the glass composition. O 0.7%, MgO 1.2%, CaO 3.5%, ZrO ₂ 5%, ZnO 5%, TiO ₂ 5%, Fe ₂ O ₃ 0.1%, and others A glass having a total component of 0.8% was prepared, and the material Young's modulus was 89.2 GPa and the material thermal conductivity was 0.89 W / mK.

Further, since this glass contains ZrO ₂ , ZnO and TiO ₂ in total 15%, the liquidus temperature rises and the glass becomes devitrified at the time of fiberization, so that it cannot be fiberized.

  The results of Examples 1 to 11 and Comparative Examples 1 to 5 are summarized in (Table 1).

  As mentioned above, the vacuum heat insulating material and glass composition concerning this invention improve the raw material intensity | strength of glass, and have the heat insulation performance superior to the past.

  As a result, the vacuum heat insulating material can be used not only for widening the performance by further improving the performance, but also as a member requiring high strength, such as a building material and a car, as a single glass composition.

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 (4)

A core material made of glass fiber is coated with an outer packaging material having a gas barrier property, and the inside of the outer packaging material is sealed under reduced pressure, and the glass fiber is alkali silicate glass, and among ZrO ₂ , ZnO, and TiO ₂ , wherein at least any one component, and said _ZrO 2, ZnO, the total of the TiO ₂ in weight%, the vacuum heat insulating material having a composition contained within the 0.5 to 13%. Glass fibers, in weight%, at least SiO ₂ is 50-70%, _Al 2 _{O 3} is 0-7% 8-20% combined Na ₂ O and _{K 2} O, MgO is Less than six%, CaO The vacuum heat insulating material according to claim 1, comprising a composition in which the total content of the components is within a range of 2 to 15% and the total weight percent of these components does not exceed 100%. Glass fibers, in _weight%, the vacuum heat insulating material according to claim 1 or 2 containing B 2 _{O 3} in the range of 0.1 to 12%.   The glass composition used for the vacuum heat insulating material as described in any one of Claim 1 to 3.

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