JP2013104491A - Method for manufacturing vacuum heat insulating material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a vacuum heat insulating material, the method by which the vacuum heat insulating material having high surface flatness and superior heat insulation can be manufactured.SOLUTION: The method for manufacturing the vacuum heat insulating material includes: employing a vacuum heat insulating material manufacturing device having a chamber for receiving powder used in a core material in a gas impermeable packaging material being an exterior material of the vacuum heat insulating material, and a conveying mechanism conveying the powder to the chamber; introducing the powder decompressed during the conveying into the decompressed chamber; and receiving and hermetically sealing the powder in the packaging material in the chamber. In the method, the fumed silica powder is used as the powder.

Description

  The present invention relates to a method for manufacturing a vacuum heat insulating material for manufacturing a vacuum heat insulating material in which a powder is sealed in a reduced pressure state in a gas-impermeable packaging material.

In recent years, energy saving is strongly desired from the viewpoint of preventing global warming, and energy saving is an urgent issue for household appliances.
In particular, a heat insulating material having excellent heat insulating performance from the viewpoint of efficiently using heat in a heat insulation and cold insulation device such as a refrigerator, a freezer, a vending machine, or from the viewpoint of maintaining the internal temperature at a predetermined temperature in a building. Instead of conventional insulation materials such as expanded polystyrene board and glass fiber, a gas non-permeable packaging material is used as an exterior material, and a core material is enclosed inside the packaging material to provide a certain amount of space. The use of a vacuum heat insulating material that is provided and whose inside is in a reduced pressure (vacuum) state has been studied.

As such a vacuum heat insulating material, various materials such as a fiber type, a powder type, and a foamed resin type have been studied as a core material. However, if a fiber type or a foamed resin type core material is used, Since heat conduction is likely to occur, the use of powder as the core material is advantageous in improving heat insulation.
On the other hand, powder is more difficult to handle because it is more likely to scatter than fibers and foamed resins. When manufacturing vacuum insulation using powder as a core material, when using fiber-based or foamed resin-based core materials There is a risk that careful work will be required.

Therefore, an inner bag is formed with a breathable sheet or the like that allows gas to pass while suppressing the passage of the powder, and the powder is enclosed in the inner bag as a core material. It has been studied to place the inside of the packaging material in a decompressed state after the bag is accommodated in the packaging material.
However, when the inner bag filled with the powder is housed in the packaging material, the inside of the packaging material is decompressed and the gas in the inner bag is discharged outside the inner bag. As a result, the powder flows and is unevenly distributed in the inner bag due to the flow of the gas discharged, and as a result, the obtained vacuum heat insulating material may have a low surface flatness. The vacuum heat insulating material is used as, for example, a housing building material and is bonded to another housing building material through an adhesive. When a vacuum heat insulating material having a low surface flatness is used, the vacuum heat insulating material and the other There is a possibility that the contact area with the housing building material becomes small and the adhesive force by the adhesive becomes weak.

For this reason, after the vacuum heat insulating material is produced in the chamber as described above, the vacuum heat insulating material is sandwiched between the two pressing members having a flat surface before returning to the atmospheric pressure in the chamber. A method for increasing the flatness of the surface of the vacuum heat insulating material by pressing is proposed (for example, Patent Document 1).
However, there is a problem in that it is difficult to evenly distribute the powder biased in the inner bag into the inner bag only by pressing with the pressing member, and the flatness of the surface of the vacuum heat insulating material cannot be sufficiently increased.

  In addition, it has also been proposed to seal the powder, which is used as the core material of the vacuum heat insulating material without using the inner bag, after having been reduced in pressure in advance and accommodated in a packaging material (for example, Patent Document 2). Specifically, the manufacturing method of the vacuum heat insulating material described in Patent Document 2 described below includes a plurality of stages as a transport mechanism for storing a packaging material in a vacuum chamber and transporting powder to the chamber. This is a method in which a hopper is employed, the powder is decompressed while being conveyed to the chamber through the hopper, and the powder is accommodated in the packaging material and sealed.

Japanese Patent Laid-Open No. 8-68592 Japanese Examined Patent Publication No. 7-98524

  However, even in an embodiment in which no inner bag is used, a vacuum heat insulating material having a sufficiently high surface flatness may not be obtained.

  An object of the present invention is to solve the above-mentioned problems, and to provide a method for producing a vacuum heat insulating material capable of producing a vacuum heat insulating material having high surface flatness and excellent heat insulating properties. Yes.

  As a result of intensive research by the present inventors, it was found that by using fumed silica powder as the core material, the obtained vacuum heat insulating material has high surface flatness, and the completion of the present invention is conceived. It came.

  That is, the method for manufacturing a vacuum heat insulating material according to the present invention includes a chamber for containing a powder used for a core material in a gas-impermeable packaging material that is an exterior material of the vacuum heat insulating material, and conveying the powder to the chamber. And a vacuum heat insulating material manufacturing apparatus having a transport mechanism that introduces the powder that has been decompressed during the transport into the chamber that has been decompressed, and allows the packaging material to accommodate the powder in the chamber. A method for producing a vacuum heat insulating material for sealing, wherein fumed silica powder is used as the powder.

According to the present invention, since the powder is used for the core material, the obtained vacuum heat insulating material has excellent heat insulating properties. Further, since fumed silica powder is used as the powder, the obtained vacuum heat insulating material has high surface flatness. For example, when this vacuum heat insulating material is used as a housing building material and bonded to another housing building material via an adhesive, the surface flatness is high. The contact area is large, and the adhesive strength by the adhesive is stronger than when the surface flatness is low.
That is, according to the present invention, a vacuum heat insulating material having high surface flatness and excellent heat insulating properties can be manufactured.

The apparatus block diagram which showed an example of the vacuum heat insulating material manufacturing apparatus utilized for manufacture of a vacuum heat insulating material ((a): Schematic whole figure, (b): Chamber expanded sectional view).

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
The vacuum heat insulating material manufactured by the manufacturing method according to the present embodiment is a gas non-permeable packaging material serving as an exterior material that is sealed by containing the powder used for the core material, and the inside is in a reduced pressure (vacuum) state. It was made to.

  The gas-impermeable packaging material used in the method for manufacturing a vacuum heat insulating material in the present embodiment has an internal volume capable of accommodating a predetermined amount of powder, is excellent in gas barrier properties, and is bonded by heat sealing. The bag-shaped packaging material (hereinafter also referred to as “packaging bag”) is formed by sealing two rectangular laminate sheets in three directions. A portion corresponding to one side of the rectangle is opened.

The laminate sheet has at least a surface protective layer and a gas barrier layer in order from the surface side so that the sealed state (vacuum state) of the core material (powder) can be maintained over a long period of time. It is preferable to employ one having a heat-sealing layer.
For example, examples of the gas barrier layer include those formed of a rolled foil or vapor-deposited film of a metal such as aluminum. Usually, the laminate sheet can be provided with a thickness of 1 μm to 100 μm.
When this gas barrier layer is formed of a vapor deposition film, vapor deposition may be performed on either the member that forms the surface protective layer or the member that forms the thermal fusion layer.
Note that gas molecules can diffuse into the polymer, and it is difficult to ensure sufficient gas barrier properties with a film formed of only the polymer, but a laminate sheet having a gas barrier layer formed of this metal is employed. This prevents gas molecules from passing in the sheet thickness direction and suppresses a decrease in the degree of vacuum inside the packaging bag.

Moreover, the surface protective layer is provided in order to provide the laminate sheet with a function of protecting the gas barrier layer from corrosion and scratches as one purpose, and usually has a thickness of 5 μm to 200 μm. And may be formed by a stretched product of a polyethylene terephthalate film or a polypropylene film.
Furthermore, the surface protective layer is not limited to a single layer, and it is possible to improve mechanical properties such as bending resistance of the laminate sheet by providing a polyamide film or the like on the outside of the stretched film.

The heat-sealing layer is provided so that the powder in a reduced pressure state is contained in a packaging bag, and then the laminate sheets are bonded by heat sealing so that the powder can be sealed in a reduced pressure state. For example, it can be formed by a low density polyethylene film, a high density polyethylene film, a polypropylene film, a polyacrylonitrile film, an unstretched polyethylene terephthalate film, or the like.
If the thickness of the heat-fusible layer is too thin, it may cause a sealing failure. On the other hand, if the thickness of the heat-fusible layer is too thick, the heat-sealed layer may be exposed between the gas barrier layers. A thick polymer layer inside and outside the bag is easily formed by the heat-sealing layer, and gas molecules are likely to flow through the polymer layer.
That is, when the thickness of the heat-sealing layer is too thick, there is a possibility that the lowering of the degree of vacuum inside the vacuum heat insulating material is accelerated.
From such a viewpoint, the thickness of the heat-sealing layer is preferably 20 μm to 100 μm.

As the powder used for the core of the vacuum heat insulating material, fumed silica powder is used. Fumed silica is an amorphous silica produced by flame hydrolysis and is also called fumed silica. Fumed silica can be produced without going through a liquid phase, for example, by hydrolyzing silicon tetrachloride at high temperature in an oxyhydrogen flame. As for fumed silica, the average primary particle size of 100 arbitrary particles measured with a transmission electron microscope is about 5 to 100 nm.
As the fumed silica powder introduced into the transport mechanism, it is preferable to use a fumed silica powder having a water content of less than 1% by mass. Normally, since the powder contains moisture, when the pressure inside the packaging material containing the powder is reduced, it takes time to reduce the pressure to the desired pressure because the moisture contained in the powder volatilizes from the powder. In addition, when moisture contained in the powder volatilizes from the powder as water vapor and is discharged from the inside of the packaging material to the outside of the packaging material, the powder is unevenly distributed in the packaging material due to the flow of this water vapor. As a result, the obtained vacuum heat insulating material may have a low surface flatness. However, if a fumed silica powder having a moisture content of less than 1% by mass is used as the fumed silica powder to be introduced into the transport mechanism, the fumed silica powder is transported by the transport mechanism under reduced pressure. Since the amount of moisture in the fumed silica powder introduced into the chamber is reduced, the amount of moisture in the fumed silica powder introduced into the chamber is less than 1% by mass, and the adverse effects due to the water vapor can be suppressed. That is, by using a fumed silica powder having a moisture content of less than 1% by mass as the fumed silica powder introduced into the transport mechanism, a vacuum heat insulating material having a high surface flatness can be produced in a short time. There is an advantage.
The water content of the powder is measured according to the method described in JIS K0068: 2001 (Method for measuring water content of chemical products). Specifically, 20 to 100 mg of a weighed powder sample is contained in a moisture measuring container, and the container is placed in a Karl Fischer moisture measuring device CA-200 and a moisture vaporizer VA-236S manufactured by Mitsubishi Chemical Analytech Co., Ltd. Set and measure the amount of water. In addition, Aquamicron AX and Aquamicron CXU manufactured by API Corporation are used for the anolyte and catholyte, respectively, the measurement temperature is 200 ° C., the carrier gas is N ₂ , and the flow rate is 250 ml / The water content is measured at min. The number of test of the sample is three times, and the moisture content of the moisture measurement container as a blank container measured simultaneously from the moisture content of each sample including the moisture contained in the moisture measurement container (arithmetic average value of the number of tests twice) ) Is subtracted, and the value is taken as the amount of water contained in the powder sample. As the final result, the water content (mass%) in the three samples is arithmetically averaged. The moisture content of the powder sample after drying is measured by heating the powder sample in an oven at a predetermined temperature for 3 hours, substituting the air in the oven with N ₂ , and cooling to room temperature in the oven. The mass of the powder sample itself is weighed, and the moisture content is measured by the above method.
Moreover, it is preferable that the density contained in the vacuum heat insulating material obtained is 100-250 kg / m < ³ >. The manufacturing method of the vacuum heat insulating material of this embodiment has the advantage that the thermal conductivity per unit volume becomes small and the heat insulating property of the obtained vacuum heat insulating material is excellent because the density of the powder is 250 kg / m ³ or less. Moreover, when using the obtained vacuum heat insulating material as a housing building material etc., there also exists an advantage that it is excellent in lightweight property. In addition, the method of manufacturing the vacuum heat insulating material of the present embodiment is obtained because the density of the powder is 100 kg / m ³ or more, so that the radiant heat transfer of the obtained vacuum heat insulating material is suppressed and the thermal conductivity is reduced. There is an advantage that the heat insulating property of the vacuum heat insulating material is excellent.

  In addition to the formation of voids, the powder may contain a component effective for adsorption such as outgas generated from a packaging bag made of a gas-impermeable material. As adsorbent, contains physical adsorbent particles such as synthetic zeolite, activated carbon, activated alumina, silica gel, dawsonite, hydrotalcite, and chemical adsorbent particles such as oxides and hydroxides of alkali metals and alkaline earth metals. Can be made.

Next, an example of a vacuum heat insulating material manufacturing apparatus suitable for use in carrying out the method for manufacturing a vacuum heat insulating material of the present invention will be described with reference to FIG.
FIG. 1 is a diagram showing an apparatus configuration of a vacuum heat insulating material manufacturing apparatus, (a) is a schematic overall view, and (b) is a diagram showing an internal structure of a chamber 1.
As shown in FIG. 1, the vacuum heat insulating material manufacturing apparatus used in the present embodiment includes a chamber 1 for containing a powder used for a core material in a gas-impermeable packaging material that is an exterior material of the vacuum heat insulating material, And a transport mechanism 2 for transporting the powder to the chamber 1.

  The chamber 1 accommodates a bag-shaped packaging material 3 (packaging bag 3) therein, and is configured so that the packaging bag 3 can be accommodated under a reduced pressure condition. It is formed so that the powder in a state is accommodated in the packaging bag 3 and sealed.

More specifically, the chamber 1 in the present embodiment includes a storage room 11 for introducing a packaging bag 3 made of a gas-impermeable material into the chamber 1 from the outside, and the packaging bag 3 under reduced pressure. A filling chamber 12 for containing the powder and a seal chamber 13 for sealing the packaging bag 3 ′ in which the powder is contained in the filling chamber 12 are provided side by side. The chamber 12 is partitioned by a partition material 14 that can be opened and closed, and the filling chamber 12 and the seal chamber 13 are also partitioned by a partition material 15 that can be opened and closed.
That is, the chamber 1 is in a state in which the packaging bag 3 can travel between the storage room 11 and the seal chamber 13 by opening the partition members 14 and 15, and the partition members 14 and 15 are It is formed so that each chamber can be individually decompressed by being closed.
The chamber 1 has a door 17 for accommodating the packaging bag 3 in the storage room 11 and a door 18 for taking out the vacuum heat insulating material from the seal chamber 13.

  In the present embodiment, as described above, the packaging bag 3 is a bag body in which two pieces of gas-impermeable rectangular films that can be heat-sealed are bonded together and a portion corresponding to one side of the rectangle is opened. In the filling chamber 12, a holder 12 a for holding the packaging bag 3 in a state where the packaging bag 3 is largely opened upward, and the packaging bag 3 are placed on the packaging bag 3. A mass meter 12b for weighing the amount of the packaging bag, and a lifting mechanism (not shown) capable of moving the packaging bag 3 up and down in the filling chamber together with the mass meter 12b. Yes.

  The seal chamber 13 is provided with a heat sealer 13 a for heat-sealing the opening of the packaging bag 3 containing a predetermined amount of powder to seal the packaging bag 3.

The chamber 1 is configured to move together with the jig 16 between the storage room 11 and the seal chamber 13 with the packaging bag 3 fixed to the jig 16. 16 includes two molded plates 16a for finishing the vacuum heat insulating material to a uniform thickness as a whole.
The molding plate 16a is provided so that the packaging bag 3 is sandwiched from the front and rear when the packaging bag 3 is fixed to the jig 16, and the distance between them can be adjusted. It has been.
That is, for example, if the powder is accommodated only by grasping each one of the left and right ends of the packaging bag, the bottom of the packaging bag swells greatly due to the weight of the powder, and the vacuum heat insulating material is thinner at the top than the bottom Will be formed.
On the other hand, when the inside of the chamber 1 is fixed to the jig 16 and the packaging bag 3 is moved as in this embodiment, the swelling of the packaging bag 3 is regulated by the molding plate 16a when the powder is accommodated. Therefore, it becomes easy to obtain a vacuum heat insulating material having a uniform thickness as a whole.

  The jig 16 is configured to move while vibrating the packaging bag 3 ′ when the packaging bag 3 ′ containing powder is moved from the filling chamber 12 to the seal chamber 13. . The powder usually tends to agglomerate and become a clump, and as a result, a gap may be formed between the powder clumps in the packaging bag 3 ′, and the powder may be biased in the packaging bag 3 ′. Is configured to vibrate the powder in the packaging bag 3 ′, so that the powder in the packaging bag 3 ′ can be leveled, and the bias of the powder is less likely to occur in the packaging bag 3 ′. There is an advantage that you can.

The transport mechanism 2 for transporting powder to the chamber 1 includes three first, second and third hoppers 21a, 21b, 21c and a compressor 24 for compressing the powder. The hoppers 21a, 21b, 21c and the compressor 24 are connected in series in order from the upstream side.
The second and third hoppers 21b and 21c are provided with first and second vacuum pumps 22a and 22b, respectively, for evacuating the gas in the spaces in the second and third hoppers 21b and 21c to reduce the pressure. ing. As the vacuum pumps 22a and 22b, a mechanical booster pump, an oil rotary pump, a water ring pump, or the like can be employed.
The compressor 24 is for compressing the powder so that the powder can be easily supplied to the packaging bag 3. Specifically, the tubular body in which the powder is circulated and the inner space is cylindrical, and the tube The screw may be provided around the rotation axis extending along the center of the inner space and having a flight spirally arranged around the rotation axis. In addition, the compressor 24 may be constituted by the tube body and a piston that simply pushes and compresses the powder.
Each of the hoppers 21a, 21b, 21c and the compressor 24 is formed with a powder supply part for taking in powder at the upper part and a powder discharge path for discharging the powder at the lower part.
The powder discharge path of the first hopper 21a is connected to the powder supply part of the second hopper 21b, the powder discharge path of the second hopper 21b is connected to the powder supply part of the third hopper 21c, and the powder of the third hopper 21c. The discharge path is connected to the compressor 24. In this embodiment, after passing the powder through the first hopper 21a, the powder is continuously passed through the second hopper 21b, and then the third The transport mechanism 2 is configured to pass through the hopper 21c and be compressed by the compressor 24.
The transport mechanism 2 includes first, second, and third valves 23a, 23b, and 23c, respectively, in the powder supply portions of the first, second, and third hoppers 21a, 21b, and 21c. Each powder discharge path is configured to be opened and closed by valves 23a, 23b, and 23c. Examples of the valves 23a, 23b, and 23c include a rotary valve.
The compressor 24 has a powder discharge path provided in a lower portion thereof plunged into the filling chamber 12 of the chamber 1 from above, and the powder is put into the packaging bag 3 through a supply nozzle 24a attached to the powder discharge path. It arrange | positions so that it can discharge.

Then, the manufacturing method of the vacuum heat insulating material using such a vacuum heat insulating material manufacturing apparatus is demonstrated.
First, on the chamber 1 side, a packaging bag 3 fixed to a jig 16 is prepared. The space between the storage chamber 11 and the filling chamber 12 is closed with a partitioning member 14 and the filling chamber 12 and the sealing chamber 13 are closed. In the meantime, the chamber is closed with the partition member 15, and the decompression of the filling chamber 12 and the seal chamber 13 is started using the vacuum pump 19.
On the other hand, the door 17 of the storage room 11 is opened, the packaging bag 3 fixed to the jig 16 is accommodated in the storage room 11, the door 17 of the storage room 11 is closed, and the decompression of the storage room 11 is started.
Note that the jig 16 and the packaging bag 3 may be accommodated not only in one set but also in a plurality of sets of storage rooms 11.
Thereafter, at least when the storage chamber 11 and the filling chamber 12 reach a desired degree of vacuum, the packaging bag 3 is moved from the storage chamber 11 to the filling chamber 12 with the partition member 14 opened and fixed to the jig 16. The mass meter 12b on which the jig 16 is placed is moved upward by the elevating mechanism, and the tip of the supply nozzle 24a attached to the lower portion of the compressor 24 is attached to the packaging bag 3. The movement by the elevating mechanism is stopped when entering from the upper opening.

At the same time, on the transport mechanism 2 side, the powder discharge path of the hoppers 21a, 21b, and 21c is closed by the valves 23a, 23b, and 23c, and the first hopper 21a contains the powder to be used as a core material. Let
Next, the first and second vacuum pumps 22a and 22b provided in the second and third hoppers 21b and 21c, respectively, are operated, and the insides of the second and third hoppers 21b and 21c are decompressed.
Then, by opening the powder discharge path of the first hopper 21a by the first valve 23a, the powder in the first hopper 21a is supplied to the second hopper 21b by natural fall.
Next, when a desired amount of powder is supplied to the second hopper 21b, the powder discharge path of the first hopper 21a is closed by the first valve 23a, and the first vacuum pump 22a is continuously driven. As a result, the gas in the powder supplied from the first hopper 21a to the second hopper 21b is discharged to the external space of the second hopper 21b, and the powder is brought into a reduced pressure state.
Then, the powder discharge path of the second hopper 21b is opened by the second valve 23b, whereby the powder in the second hopper 21b is supplied to the third hopper 21c by natural fall.
Next, when a desired amount of powder is supplied to the third hopper 21c, the powder discharge path of the second hopper 21b is closed by the second valve 23b, and the second vacuum pump 22b is continuously driven. Accordingly, the powder in the powder supplied from the second hopper 21b to the third hopper 21c is discharged to the external space of the third hopper 21c, whereby the powder is further decompressed.
The powder discharge path of the third hopper 21c is opened by the third valve 23c, so that the powder in the reduced pressure state (for example, 10 Pa or less) in the third hopper 21c is naturally dropped to the compressor 24. To supply.
Next, when a desired amount of powder is supplied to the compressor 24, the powder discharge path of the third hopper 21 c is closed by the third valve 23 c, and the powder is compressed by the compressor 24.
Thereafter, the powder compressed from the compressor 24 through the supply nozzle 24a is accommodated in the packaging bag 3. The mass increase of the packaging bag 3 observed by the mass meter 12b, that is, the amount of powder accommodated is desired. When the value is reached, the supply of powder from the supply nozzle 24a to the packaging bag 3 is stopped so that no more powder is accommodated in the packaging bag 3.
Then, the packaging bag 3 is lowered by the lifting mechanism, the partition 15 between the sealing chamber 13 is opened, and the packaging bag 3 ′ containing the powder is moved from the filling chamber 12 to the sealing chamber 13.

At this time, if a new packaging bag 3 is waiting in the evacuation chamber 11 in a decompressed state, the warehousing chamber 11 is moved along with the movement of the packaging bag 3 ′ containing the powder to the seal chamber 13. A new packaging bag 3 may be introduced from the warehousing chamber 11 to the filling chamber 12 by opening the partitioning member 14 therebetween.
The process of raising the new packaging bag 3 by the elevating mechanism and allowing the supply nozzle 24a to enter from the upper opening to accommodate a predetermined amount of powder can be performed in the same manner as described above.

  On the other hand, when the packaging bag 3 ′ containing powder is moved from the filling chamber 12 to the seal chamber 13, the packaging bag 3 ′ is moved by the jig 16 while vibrating. As a result, the agglomerates formed by agglomeration of the powder by compression can be crushed by vibration to level the powder in the packaging bag 3 ′, making it difficult for the powder to be biased in the packaging bag 3 ′. be able to.

The packaging bag 3 ′ moved to the seal chamber 13 can be made into a vacuum heat insulating material by sealing the powder contained by heat-sealing the upper opening with a heat sealer 13 a.
In addition, if needed, the partition 15 between the filling chambers 12 is closed to release the reduced pressure state of the seal chamber 13, and the vacuum created while the powder bag 3 is being accommodated in the adjacent filling chamber 12. The heat insulating material can be taken out from the chamber 1.

By the way, when the vacuum heat insulating material is placed under atmospheric pressure, the packaging bag 3 is pressed against the powder contained therein at a pressure corresponding to atmospheric pressure.
Therefore, if the powder accommodation state is uneven, unevenness due to the unevenness is likely to be formed on the surface of the packaging bag 3, but in this embodiment, fumed silica powder is used as the powder. The vacuum heat insulating material can be made to have excellent fluidity inside the packaging bag 3, and unevenness can be hardly formed. This is because the fumed silica itself is easily maintained in a good fluidity before compression, even if the fumed silica is once compressed in a vacuum due to the compressive restoring force of the fumed silica itself.
That is, even if the powder accommodation state is biased before being placed at atmospheric pressure, the powder is flattened when the pressure is applied by the packaging bag 3 under atmospheric pressure and vacuum insulation is performed. It is possible to suppress the formation of irregularities on the surface of the material.

In the heat sealing in the sealing chamber 13, for example, if powder adheres to the sealing portion, the sealing performance is impaired, and air can easily enter the vacuum heat insulating material as compared with the case where the heat sealing is performed well.
In this respect, in the vacuum heat insulating material manufacturing apparatus shown in the present embodiment, the packaging bag is laid sideways and the supply nozzle 24a is inserted from the side in order to accommodate the powder from above in the packaging bag opened at the top. Compared with the case where the powder is accommodated in the embodiment, the powder does not easily adhere to the vicinity of the opening of the packaging bag, and a good sealing property can be easily obtained.

In addition, even when powder is stored from above in a packaging bag having an upper opening, there is a risk of powder adhering to the vicinity of the opening of the packaging bag if the powder is swollen at the time of storage. As illustrated, the method for manufacturing a heat insulating material compresses the powder with the compressor 24 and discharges the compressed powder in a compressed state from the supply nozzle 24a, so that the rise of the powder is suppressed. There is.
In such a point, the manufacturing method of the vacuum heat insulating material shown in the present embodiment can suppress the generation of defective products whose heat insulating performance deteriorates in a short time, and improves the yield of the vacuum heat insulating material. It can be said that this is an effective method.

In the present embodiment, the amount of the powder introduced into the packaging bag 3 is measured by the mass meter 12b, but the powder compressed by the compressor 24 is used instead of the method exemplified in the present embodiment. It may be once weighed with a weighing container (mass weighing), and the weighed powder may be introduced into the packaging bag 3. Since the powder that has been weighed and introduced into the packaging bag 3 is decompressed, it is difficult to scatter when introduced into the packaging bag 3, and it is possible to introduce an amount of powder that is substantially measured.
Further, the powder divided into the amount necessary to be introduced into one packaging bag 3 is conveyed to the chamber 1 while being decompressed through the hoppers 21a, 21b, 21c (packet type supply), and supplied to the packaging bag 3. Also good.
Furthermore, in this embodiment, although the vacuum heat insulating material manufacturing apparatus is provided with the compressor 24 introduced into the packaging bag 3, in the present invention, the vacuum heat insulating material manufacturing apparatus is not provided with the compressor 24. In this case, the third valve 23c is a rotary valve, and the rotary valve includes a rotor and a case that houses the rotor, and the inside of the case is configured to be decompressed. It is preferable that the vacuum heat insulating material manufacturing apparatus is configured to supply powder filled in a reduced pressure by rotating the rotor while reducing the pressure in the case.
Note that, instead of the hoppers 21a, 21b, and 21c, the divided powder may be conveyed using a screw or a piston. The use of a screw or a piston has an advantage that the transport mechanism 2 itself can be easily downsized as compared with the case of using a hopper.

  Furthermore, in the present embodiment, in that the vacuum heat insulating material can be efficiently manufactured, a chamber whose interior is divided into three chambers (a warehousing chamber, a filling chamber, and a sealing chamber) that can be individually decompressed is provided. Although the aspect to utilize is illustrated, the manufacturing method of the vacuum heat insulating material of this invention is not limited to such an aspect.

  Next, although the Example and comparative example of manufacture of a vacuum heat insulating material are given and this invention is demonstrated in more detail, this invention is not limited to these.

Example 1
First, using a vacuum heat insulating material manufacturing apparatus configured in the same way as illustrated in FIG. 1, hydrophobic fumed silica particles (trade name “Aerosil R972”, manufactured by Nippon Aerosil Co., Ltd., average particle diameter of 16 nm, A moisture content of 0.21% by mass) was quickly charged into the first hopper, and the upper portion of the first hopper was closed with a lid, and then the vacuum pump of the transport mechanism was operated, and then the vacuum pump of the chamber was operated.
When the chamber filling chamber reached a reduced pressure of 100 Pa, the pressure inside the compressor was 20 Pa.
A packaging bag (outer width 250 mm, length 370 mm, seal width 10 mm) made of a gas-impermeable material is fixed to a jig and placed in a storage room, and the storage room is evacuated until the pressure reaches 100 Pa. The pressure was reduced.
The gas impermeable material at this time is a laminate film (made by Showa Denko Packaging Co., Ltd.) made of a polyamide resin film with a surface protective layer of 40 μm, an aluminum foil with a gas barrier layer of 6 μm, and a polyethylene resin film with a heat seal layer of 50 μm. )It was used.
After making the pressure in the warehousing chamber and the filling chamber substantially the same, the partition material is opened, the jig holding the packaging bag is moved from the warehousing chamber to the filling chamber, and opens downward in the filling chamber. It was stopped just below the supply nozzle, and the packaging bag was raised together with the jig by the lifting mechanism.
Next, after the powder is reduced in pressure in the second and third hoppers and compressed by the compressor, the compressed powder is filled into the packaging bag, and a predetermined amount of the powder is accommodated in the packaging bag. The packaging bag containing the powder was lowered by the lifting mechanism.
Open the partition between the filling chamber and the seal chamber and move the packaging bag together with the jig to the seal chamber in order to move the packaging bag containing the powder into the seal chamber that has been adjusted to the same pressure as the filling chamber in advance. The opening part of the said packaging bag was heat-sealed with the heat sealer, and after closing the partition material between a filling chamber, this sealing chamber was open | released to air | atmosphere and the vacuum heat insulator which does not use an inner bag etc. was manufactured. When the obtained vacuum heat insulating material was confirmed, the surface was flat.
Moreover, the same operation was repeated and the vacuum heat insulating body was able to be manufactured continuously.
The work during this time was simple, and the manufactured vacuum heat insulating material was excellent in heat insulating performance and excellent in that no substantial decrease in heat insulating performance was observed over time.

(Example 2)
Example 1 was used except that fumed silica (trade name “Aerosil RX-300-5”, manufactured by Nippon Aerosil Co., Ltd., average particle size 7 nm, water content 0.33 mass%) was used as the powder. A vacuum heat insulating material was produced. When the obtained vacuum heat insulating material was confirmed, the surface was flat.
Moreover, the same operation was repeated and the vacuum heat insulating body was able to be manufactured continuously.
The work during this time was simple, and the manufactured vacuum heat insulating material was excellent in heat insulating performance and excellent in that no substantial decrease in heat insulating performance was observed over time.

(Comparative Example 1)
As a powder, porous spherical silica (trade name “Godball B-25C”, manufactured by Suzuki Oil & Fats Co., Ltd., average particle size 5 μm, moisture content 4.78% by mass) heated to 150 ° C. (moisture content 0.23 mass) %) Was used in the same manner as in Example 1 to produce a vacuum heat insulating material.
The obtained vacuum heat insulating material did not have a sufficiently high flatness due to uneven surface.

  1: chamber, 2: transport mechanism, 3: packaging material (packaging bag) 3 ': packaging material (packaging bag), 11: storage room, 12: filling chamber, 12a: holding tool, 12b: mass meter, 13: seal Chamber, 13a: Heat sealer, 14: Partition material, 15: Partition material, 16: Jig, 16a: Molded plate, 17: Door, 18: Door, 19: Vacuum pump, 21a: First hopper, 21b: Second hopper 21c: third hopper, 22a: first vacuum pump, 22b: second vacuum pump, 23a: first valve, 23b: second valve, 23c: third valve, 24: compressor, 24a: supply nozzle

Claims (3)

Using a vacuum heat insulating material manufacturing apparatus having a chamber for containing powder used for a core material in a gas-impermeable packaging material serving as a vacuum heat insulating material, and a transport mechanism for conveying the powder to the chamber, A method for producing a vacuum heat insulating material, wherein the powder brought into a reduced pressure state during the transfer is introduced into the chamber in a reduced pressure state, and the powder is housed in the packaging material in the chamber and sealed.
A fumed silica powder is used as the powder. A method for producing a vacuum heat insulating material.   The manufacturing method of the vacuum heat insulating material of Claim 1 which vibrates the said packaging material in which the powder was accommodated after the said accommodation in the said packaging material in the said chamber, and implements the said sealing after this vibration.   The manufacturing method of the vacuum heat insulating material of Claim 1 or 2 using the fumed silica powder whose moisture content is less than 1 mass% as a fumed silica powder introduce | transduced into the said conveyance mechanism.

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