JP2006125600A - Vacuum maintaining device and vacuum insulation material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vacuum insulation material including a vacuum maintaining device having high aging reliability without losing gas absorption capability due to moisture suction of a pellet having gas absorption capability. <P>SOLUTION: The moisture in the interior of the vacuum insulation material 1 is sucked with priority using a desicant 5 having an external capsule material 6, thereby preventing the pellet 3 having gas absorption capability from sucking moisture and holding the gas absorption performance of the pellet 3 so that the reliability of the vacuum insulation material 1 itself can be enhanced. Further, it is possible to provide a high-performance vacuum insulation material 1 without performing a core material 2 drying process before vacuum packaging, which is an ordinary manufacturing process. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a vacuum maintaining device and a vacuum heat insulating material provided with the vacuum maintaining device.

  Until now, various efforts have been made to save energy because of the importance of preventing global warming, which is a global environmental problem. Among them, a vacuum heat insulating material, which is a high performance heat insulating material, has attracted attention as a device for realizing energy consumption by heat insulation in electrical appliances and houses.

  A vacuum heat insulating material exhibits a high heat insulating property by sealing a core material holding a space to a jacket material under reduced pressure. Usually, the core material is used after being sufficiently dried before being enclosed in the jacket material. This is because if the core material is sealed in a state of containing moisture, it becomes water vapor inside and cannot maintain a reduced pressure state, resulting in deterioration of the heat insulation performance.

  Conventionally, this type of vacuum heat insulating material is provided with an adsorbent to adsorb gas and moisture entering from the outside, or gas and moisture generated from the core material in the interior, and maintain the internal reduced pressure state. Increases reliability over time.

Further, when a Ba—Li alloy is used as the adsorbent, this material has a gas adsorption ability such as CO, CO ₂ , O ₂ , H ₂ , N _{2 and the} like, and has a high affinity for water vapor. However, when the Ba—Li alloy reacts with water vapor and adsorbs moisture, the gas adsorption performance is impaired by the amount of moisture adsorbed.

  Therefore, it has been proposed to combine a desiccant for removing water vapor coming into contact with the Ba—Li alloy and maintaining the adsorption ability for other gas species (see, for example, Patent Document 1).

FIG. 6 shows a conventional vacuum maintaining device described in Patent Document 1. In FIG. In the conventional vacuum maintaining device, an adsorbent is contained in a gas-impermeable container 11, a Ba—Li alloy pellet 13 contained in the lower part of the container 11, and a desiccant contained in the upper part of the container 11. And the polymer material net 12 covering the upper pellet 14.
Japanese National Patent Publication No. 9-512088

  However, in the above conventional configuration, it is difficult to increase the air resistance of the desiccant pellets 14, and moisture that could not actually be adsorbed when passing through the desiccant is adsorbed by the Ba-Li alloy pellets 13. Resulting in.

  In addition, when there is no core material drying step before vacuum packaging, which is a normal vacuum insulation material manufacturing process, or when left under high humidity, a large amount of water vapor is present inside the vacuum insulation material, so the adsorbent is By adsorbing moisture, the original gas adsorption capacity is reduced, and the vacuum maintaining effect due to the gas adsorption cannot be fully exhibited. As a result, there has been a problem that the heat insulating performance of the vacuum heat insulating material deteriorates with time without maintaining the internal reduced pressure state.

  The present invention solves the above-described conventional problems, and provides a vacuum maintaining device capable of maintaining an internal decompressed state for a long period of time, and a vacuum heat insulating material having high reliability over time by including this vacuum maintaining device. The purpose is to do.

  In order to solve the above-described conventional problems, the vacuum maintaining device of the present invention has a gas adsorption capability and a moisture adsorption capability, a pellet whose outside air contact surface is covered with a filter portion, and a desiccant having an outer packaging material. And the air resistance in the filter portion of the pellet is larger than the air resistance in the outer packaging material of the desiccant.

  As a result, when this vacuum maintaining device is provided inside the jacket of the vacuum heat insulating material, the moisture inside the vacuum heat insulating material passes through the outer packaging material having a lower air resistance than the filter part of the pellet, and the desiccant By preferentially adsorbing moisture on the side, moisture adsorption on the pellet can be prevented, and the gas adsorption performance of the pellet can be maintained for a long period of time, so that the reliability over time of the vacuum maintaining device can be improved.

  The vacuum maintenance device of the present invention can maintain the gas adsorption performance by suppressing the moisture adsorption of the pellet, and can improve the reliability over time.

  Moreover, the vacuum heat insulating material of this invention can be made into a vacuum heat insulating material with high temporal reliability by maintaining an internal pressure-reduced state for a long time with the said vacuum maintenance device.

  The invention of the vacuum maintaining device according to claim 1 includes a pellet having a gas adsorption capability and a moisture adsorption capability, an outside air contact surface covered with a filter portion, and a desiccant having an outer packaging material, The air permeability resistance in the filter part is larger than the air resistance in the outer packaging material of the desiccant.

  As a result, moisture inside the vacuum insulation material passes through the outer packaging material having a lower air resistance than the filter part of the pellet, and moisture is preferentially adsorbed on the desiccant side, thereby preventing moisture adsorption on the pellet. Since the gas adsorption performance of the pellet can be maintained for a long period of time, the aging reliability of the vacuum maintaining device can be improved.

  The invention of the vacuum maintaining device according to claim 2 is that the filter portion in the invention according to claim 1 is a single-layer film or a multi-layer laminate having a resin film that can be thermally welded to at least the innermost layer. It is a feature.

  Thus, the pellet can be easily sealed, and the gas and moisture adsorption of the pellet in the manufacturing process can be reduced to maintain the initial high-performance gas adsorption capacity.

  In addition, the moisture that passes through the filter layer is adsorbed by the moisture adsorbent in the filter part before reaching the pellet, so that the gas adsorption capacity of the pellet is prevented from deteriorating due to moisture adsorption, and gas adsorption is performed over a long period of time. Since the effect can be obtained, it is possible to provide a vacuum heat insulating material with high temporal reliability that can maintain the internal reduced pressure state.

  The invention of a vacuum maintaining device according to claim 3 is characterized in that the filter portion in the invention according to claim 1 is a powder moisture adsorbent.

  Thereby, the water | moisture content which passes a filter part can be adsorb | sucked with the powder water | moisture-content adsorption agent of a filter part by the time it reaches | attains a pellet, and the gas adsorption effect can be maintained over a long term, without a pellet adsorb | sucking a water | moisture content.

  The invention of a vacuum maintaining device according to claim 4 is characterized in that, in the invention according to any one of claims 1 to 3, a powder moisture adsorbent is interposed between the filter portion and the pellet. To do.

  As a result, even when there is moisture that has passed through the filter part of the pellet before passing through the outer packaging material, it is adsorbed by the powder moisture adsorbent before reaching the pellet, so the pellet does not adsorb moisture. The gas adsorption performance can be maintained for a long time.

  The invention of the vacuum maintaining device according to claim 5 is characterized in that, in the invention according to claim 3 or 4, the barrier layer is interposed between the pellet and the powder moisture adsorbent.

  As a result, even when there is moisture that has passed through the filter part of the pellet before passing through the outer packaging material, the filter part temporarily traps the moisture in the powder moisture adsorbent by the barrier layer before reaching the pellet. By completely adsorbing moisture in the powder moisture adsorbent, the pellet can maintain its gas adsorption performance for a long time without adsorbing moisture.

  According to a sixth aspect of the present invention, the desiccant outer packaging material according to any one of the first to fifth aspects is a single layer resin film having a thickness of 5 μm to 100 μm. It is characterized by this.

  As a result, the desiccant outer packaging material is used as an outer packaging material with low air permeability resistance, the moisture adsorption amount in the desiccant is further increased, the moisture adsorption of the pellet is suppressed, and the gas adsorption capacity is maintained over a long period of time. be able to.

  The invention of a vacuum maintaining device according to claim 7 is a laminate in which the desiccant outer packaging material according to any one of claims 1 to 5 includes a resin film that can be thermally welded to at least the innermost layer. It is a packaging material.

  As a result, the desiccant can be easily sealed in the process of inserting the desiccant having the outer packaging material as a vacuum maintaining device into a vacuum heat insulating material, etc., and the moisture adsorption amount is suppressed even if left in the air for several minutes. Therefore, there is almost no deterioration, initial deterioration can be prevented, and a highly reliable vacuum maintaining device can be obtained.

  The invention of a vacuum heat insulating material according to claim 8 is composed of a core material and a jacket material covering the core material, and the vacuum maintenance according to claims 1 to 7 is provided inside the jacket material. It is characterized by having a device.

  As a result, the vacuum heat insulating material can maintain the internal reduced pressure state for a long period of time, and can be a vacuum heat insulating material with high temporal reliability.

  The invention of the vacuum heat insulating material according to claim 9 is the invention according to claim 8, wherein the desiccant having an inner bag covering the core material and an outer packaging material of the vacuum maintaining device is provided inside the inner bag. It is characterized by having prepared for.

  As a result, the vacuum heat insulating material can maintain the internal reduced pressure state for a long time, can prevent the core material from breaking through the outer cover material, and can be a vacuum heat insulating material with higher reliability over time.

  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 in Embodiment 1 of the present invention.

  In FIG. 1, the vacuum heat insulating material 1 includes a core material 2, a pellet 3, a filter 4, a desiccant 5, and an outer packaging material 6 by thermally welding two outer jacket materials 7. It is sealed in the material 7.

The core material 2 is an inorganic fiber molded body having a thickness of 14 mm, a width of 175 mm, and a length of 220 mm. The material of the core material 2 is an average fiber diameter of 0.1 μm to an amorphous silicate glass as a main component. 10 μm glass wool is formed into a 14 mm thick board. The bulk density of the core material 2 produced was ^{0.1g / cm 3 ~0.3g / cm 3} .

  Further, the constituent material of the core is not particularly limited, and the inorganic fiber is glass wool, ceramic fiber, rock wool, etc., and the inorganic powder is amorphous silica powder, dry silica powder, pearlite, and a mixture of these powders, etc. Organic foams include urethane continuous foam, polystyrene continuous foam, and the like, and known ones may be used.

  In forming the glass wool, a binder may be used as necessary. When the binder is used, the surface hardness after sealing is improved because the surface hardness of the core material is increased.

  Materials used for the pellet 3 are those having gas adsorption ability, such as activated carbon, zeolite, dawsonite, hydrotalcite, calcium chloride, lithium chloride, magnesium oxide, calcium oxide and other metal oxides, and magnesium hydroxide and hydroxide. Compounds such as metal hydroxides such as calcium can be used, but Ba-Li powder having a high-performance gas adsorption ability is preferably compressed into pellets, and Ba-Li powder having a particle size of 200 to 500 μm 0.2 g was used.

  The material of the filter 4 is not limited as long as the air resistance can be made larger than that of the outer packaging material 6, but the material of the filter 4 is good because it can be thermally welded if it is a single layer film. Polyethylene, polypropylene, and the like are preferable, and the air resistance may be adjusted depending on the thickness. Moreover, since the air permeability resistance of the filter portion can be further increased with a laminate packaging material, the moisture adsorbed by the pellets can be reduced.

  The desiccant 5 is not particularly limited as long as it has moisture adsorption ability, and any one selected from barium oxide, strontium oxide, phosphoric oxide, and a mixture thereof can be used. 20 g of highly versatile granular calcium oxide was used.

  The outer packaging material 6 is a low-density polyethylene film, polyethylene fiber, or Japanese paper that can be heat-welded from the inner surface. In order to adsorb a large amount of moisture to the desiccant 5 inside, the outer packaging material 6 should be reduced in its air resistance. Preferably, the low density polyethylene has been processed with innumerable holes.

  As a material constituting the outer packaging material, the innermost layer is preferably a resin film that can be thermally welded from the viewpoint of productivity, and polyethylene, polypropylene, and the like can be used.

  In order to obtain the strength of the outer packaging material with a small air resistance, it is preferable to provide a paper or fiber layer having a low barrier property on the innermost layer. Further, even if a resin film capable of heat welding is used in a single layer, moisture adsorption with the desiccant can be accelerated because of a smaller air resistance.

  As the jacket material 7, two films having a width of 225 mm and a length of 370 mm were used, and the end surfaces were sealed with a four-side seal with a width of 10 mm. As the material composition of the jacket material for the vacuum heat insulating material, the outermost layer provides protection and rigidity from impact, the middle layer secures gas barrier properties, and the innermost layer is a heat fusion layer. The film 7 has a function of sealing (heat sealing) by heat fusion of the film, but the laminate structure of the jacket material 7 is a linear low density polyethylene film having a thickness of 50 μm as a heat welding layer in order from the inner surface, gas barrier An outer sheath material having a laminate structure in which a 6 μm thick aluminum foil was used as a layer, a 25 μm thick nylon film as a protective layer, and a 15 μm thick nylon film was used.

  Films that can be used as the heat-sealing layer of the jacket material 7 include high-density polyethylene, low-density polyethylene, linear low-density polyethylene, and polypropylene, but heat sealability, gas barrier properties, and chemical attack resistance. From the viewpoint of cost and the like, high-density polyethylene is generally preferable. However, when importance is attached to stability of sealing quality and sealing strength in the reduced-pressure sealing process, it is preferable to use linear low-density polyethylene. More desirable.

  Moreover, when the use environmental temperature of a vacuum heat insulating material is comparatively high temperature of about 60 to 100 degreeC, it is more desirable to use a polypropylene. Further, the thickness of the heat-sealing layer is preferably 25 μm to 60 μm in any material in consideration of the stability of the sealing quality in the reduced-pressure sealing process and the suppression of gas intrusion from the end face of the heat-sealing part. Yes.

  In addition, you may use the film which gave metal vapor deposition for a gas barrier layer, and this can reduce the heat | fever transmitted through a film and can improve initial stage performance. For the protective layer, polyethylene terephthalate, paper or the like can be selected or combined as a material having strong puncture strength and friction strength.

Moreover, as a manufacturing method of the vacuum heat insulating material 1, the bulk density is 0.19 / cm < ³ >-the glass wool with the average fiber diameter of 0.1 micrometer-10 micrometers which has the silicate glass of an amorphous structure as a main component as mentioned above. A core material 2 having a width of 175 mm, a length of 220 mm, and a thickness of 14 mm is obtained by heat compression molding into a board shape having a thickness of about 14 mm so as to be 0.3 g / cm ³ .

  Next, the core material 2 is inserted into the outer cover material 7 which is sealed on three sides without drying, and when the pressure between the core material 2 and the outer cover material 3 is reduced to 10 Pa or less, the outer cover material 7 The vacuum heat insulating material 1 was obtained by sealing the opening part facing in the longitudinal direction by heat sealing.

  About the vacuum heat insulating material 1 comprised as mentioned above, the operation | movement and an effect | action are demonstrated below.

In the vacuum heat insulating material thus manufactured, the air resistance of the outer packaging material 6 of the applied vacuum maintaining device is about 150 sec / 100 cc at 25 ° C., and the air resistance of the filter portion is 150 sec / 100 cc to 6.8. The thermal conductivity was compared as × 10 ⁶ sec / 100 cc (atmospheric permeability 1932 cc / m ² · day · atm).

  In addition, about air resistance, it measures based on the Gurley testing machine method (JISP8117), and the resin film etc. which become a large value are converted into air resistance from the value of air permeability. In addition, after the vacuum heat insulating material was manufactured, it was left in a high-temperature and high-humidity furnace at 50 ° C. and 90% RH for 30 days, and then its thermal conductivity was measured to evaluate its performance. In addition, about heat conductivity, it measured at the average temperature of 24 degreeC using the heat sensor.

  The air permeability resistance of the filter part used for evaluation and the test results are shown in (Table 1). A sample having an initial thermal conductivity of 0.0022 W / mK is used for the test.

まず、フィルター部の透気抵抗度が前記の範囲において、初期熱伝導率はどれも０．００２２Ｗ／ｍＫであった。この真空断熱材を加速試験として、５０℃、湿度９０％で３０日間放置後の熱伝導率は、フィルター部の透気抵抗度を１５０ｓｅｃ／１００ｃｃとしたとき（外包材と同等）０．０３１Ｗ／ｍＫで、フィルター部の透気抵抗度を増加させるにつれて３０日放置後の熱伝導率は低く、高性能を維持できていることがわかる。

First, the initial thermal conductivity was 0.0022 W / mK in the air resistance of the filter portion within the above range. Using this vacuum heat insulating material as an accelerated test, the thermal conductivity after standing for 30 days at 50 ° C. and 90% humidity is 0.031 W / when the air permeability resistance of the filter part is 150 sec / 100 cc (equivalent to the outer packaging material). It can be seen that at mK, as the air resistance of the filter portion is increased, the thermal conductivity after being left for 30 days is low and high performance can be maintained.

On the other hand, if the air resistance is too high, the gas does not reach the pellet portion, and the performance cannot be maintained. Therefore, the air resistance of the filter part is preferably in the range of 250 sec / 100 cc to 1.0 × 10 ¹² sec / 100 cc. More preferably, it is in the range of 1000 sec / 100 cc to 1.0 × 10 ¹² sec / 100 cc.

(Embodiment 2)
FIG. 2 is a cross-sectional view of the vacuum heat insulating material according to the second embodiment of the present invention.

  In FIG. 2, the filter unit 4 in the first embodiment is sealed in the outer cover material 7 with the powder moisture adsorbent 8 and the outer packaging material 6 as the laminate packaging material 9, and other components are described in the first embodiment. It is the same.

  As the powder moisture adsorbent 8, the same material as the desiccant 5 can be used as a material. However, after the calcium oxide used in the desiccant 5 in Embodiment 1 is made into a powder having a particle size of about 500 μm, Covered around.

  When the evaluation was performed in the same manner as in the first embodiment, the thermal conductivity of the vacuum heat insulating material after being left for 30 days was 0.026 W when the air resistance of the powder moisture adsorbent as the filter portion was 150 sec / 100 cc. It was 0.0052 W / mK at / mK and 1000 sec / 100 cc.

  From this, it can be understood that the performance of the vacuum heat insulating material can be maintained if the air resistance of the powder moisture adsorbent is made larger than the air resistance of the outer packaging material as in the case of the first embodiment. Moreover, since the filter itself is a water | moisture-content adsorption agent, the heat insulation performance can be maintained rather than the case of Embodiment 1. FIG.

(Embodiment 3)
FIG. 3 is a cross-sectional view of the vacuum heat insulating material according to Embodiment 3 of the present invention.

  In FIG. 3, the powder moisture adsorbent 8 is interposed between the filter unit 4 and the pellet 3 in the first embodiment, and the other configurations are the same as those in the first embodiment.

  When evaluated in the same manner as in the first embodiment, the thermal conductivity of the vacuum heat insulating material after standing for 30 days is 0.013 W / mK, 1000 sec / 100 cc when the air permeability resistance of the filter portion is 150 sec / 100 cc. In this case, 0.0022 W / mK was maintained at 0.0039 W / mK and 3000 sec / 100 cc or more. From this, as can be seen from comparison with the first embodiment, it can be seen that high heat insulation performance can be maintained by adsorbing the moisture passing through the filter portion by the powder moisture adsorbent inside.

(Embodiment 4)
FIG. 4 is a cross-sectional view of the vacuum heat insulating material according to the fourth embodiment of the present invention.

  In FIG. 4, a barrier layer 9 is interposed between the powder moisture adsorbent 8 and the pellet 3 in the second embodiment or the third embodiment, and other configurations are the same as those in the first embodiment.

  When the evaluation was performed in the same manner as in the first embodiment, the thermal conductivity of the vacuum heat insulating material after being left for 30 days was 0.0037 W / mK, 1000 sec / 100 cc when the air permeability resistance of the filter portion was 150 sec / 100 cc. At the time described above, 0.0022 W / mK was maintained. From this, as can be seen in comparison with the third embodiment, by temporarily confining the moisture that has passed through the filter portion with the filter portion and the barrier layer, the powder moisture adsorbent inside adsorbs more moisture, It can be seen that higher thermal insulation performance can be maintained.

  In addition, although the same thing as a filter part was used for each barrier layer here, it is possible to remove moisture more completely in the powder moisture adsorbent by increasing the air permeability resistance of the barrier layer. Is possible.

(Embodiment 5)
FIG. 5 is a cross-sectional view of a vacuum heat insulating material according to Embodiment 5 of the present invention.

  In FIG. 5, the desiccant 5 having the core material 2 and the outer packaging material 6 was sealed by thermally welding an inner bag made of low-density polyethylene, and then the vacuum heat insulating material 1 was obtained. Other components are the same as those in the second embodiment.

  When the evaluation was performed in the same manner as in the first embodiment, the thermal conductivity of the vacuum heat insulating material after being left for 30 days was 0.012 W / mK, 1000 sec / 100 cc when the air permeability resistance of the filter portion was 150 sec / 100 cc. In this case, 0.0022 W / mK was maintained at 0.0022 W / mK at 3000 sec / 100 cc or more.

  From this, as can be seen in comparison with the second embodiment, by providing the inner bag with a function as a filter portion, moisture is adsorbed by the powder moisture adsorbent inside the inner bag, which is clearly high. Insulation performance is maintained.

  As described above, since the vacuum heat insulating material according to the present invention can maintain high heat insulating performance for a long period of time, it is a refrigerator, cooler box, vending machine, rice cooker, microwave oven, toilet, personal computer, automobile. It can also be applied to a wide range of uses such as building materials.

Sectional drawing of the vacuum maintenance device in Embodiment 1 of this invention Sectional drawing of the vacuum heat insulating material in Embodiment 2 of this invention Sectional drawing of the vacuum heat insulating material in Embodiment 3 of this invention Sectional drawing of the vacuum heat insulating material in Embodiment 4 of this invention Sectional drawing of the vacuum heat insulating material in Embodiment 5 of this invention Cross-sectional view of a conventional vacuum maintenance device

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vacuum heat insulating material 2 Core material 3 Pellet 4 Filter part 5 Desiccant 6 Outer packaging material 7 Outer coating material 8 Moisture adsorption agent 9 Barrier layer 10 Inner bag

Claims (9)

  A pellet having a gas adsorption capacity and a moisture adsorption capacity, the outside air contact surface of which is covered with a filter part, and a desiccant having an outer packaging material. A vacuum maintaining device characterized by being larger than the air resistance in the outer packaging material.   The vacuum maintaining device according to claim 1, wherein the filter part is a single-layer film or a multi-layer laminate having a resin film that can be thermally welded to at least the innermost layer.   The vacuum maintaining device according to claim 1, wherein the filter part is a powder moisture adsorbent.   The vacuum maintenance device according to any one of claims 1 to 3, wherein a powder moisture adsorbent is interposed between the filter portion and the pellet.   The vacuum maintaining device according to claim 3 or 4, wherein a barrier layer is interposed between the pellet and the powder moisture adsorbent.   The vacuum maintaining device according to any one of claims 1 to 5, wherein the desiccant outer packaging material is a single-layer resin film having a thickness of 5 µm to 100 µm.   The vacuum maintaining device according to any one of claims 1 to 5, wherein the outer packaging material of the desiccant is a laminate packaging material including a resin film that can be thermally welded to at least the innermost layer.   A vacuum heat insulating material comprising a core material and a jacket material covering the core material, wherein the vacuum maintaining device according to claim 1 is provided inside the jacket material.   The vacuum heat insulating material according to claim 8, wherein a desiccant having an inner bag covering the core material and having an outer packaging material of a vacuum maintaining device is provided inside the inner bag.

Images