JP2014025537A - Vacuum heat insulation material and refrigerator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vacuum heat insulation material and a refrigerator which are improved in thermal insulation performance.SOLUTION: A vacuum heat insulation material 50 including a core material 51 being a fiber assembly and a sheath 53 covering the core material 51 and having gas barrier properties, is characterized in that an average fiber diameter of the fiber assembly is 5.2 μm or less and that a compression strength (mm/(kg/m)), which is a value calculated by dividing a thickness (mm) of the fiber assembly under a predetermined load by a weight per 1 m(kg/m) of the fiber assembly, is 24 or more.

Description

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

  In recent years, improvement in heat insulation of home appliances and industrial equipment has been studied from the viewpoint of global environmental protection and energy saving. Resin foam, organic, and inorganic fibers are used as the heat insulating material for heat insulating the device. However, in order to improve heat insulating properties, it is necessary to increase the thickness of the heat insulating material. When the thickness of the heat insulating material is increased, the volume of the entire device is increased, and if the volume is not changed, the proportion of the space where components and the like can be mounted is reduced. Then, the vacuum heat insulating material which is excellent in heat insulation than a resin foam, an inorganic fiber, etc. is proposed. The vacuum heat insulating material is made of a gas barrier outer covering material in a bag shape, a core material made of a fiber assembly and a getter agent for gas adsorption are put inside, the inside of the bag is decompressed, and the end of the bag is sealed. To make. Compared to conventional heat insulating materials such as resin foam and inorganic fibers, the heat insulating property is 20 to 40 times, so that sufficient heat insulation can be performed even if the thickness of the heat insulating material is reduced.

  Various studies have been made to improve the heat insulation and functionality of the vacuum heat insulating material.

  As background art of this technical field, there is JP-A-2006-38122 (Patent Document 1). This gazette includes a core material, a moisture adsorbent, the core material, and an outer packaging material having a gas barrier property that covers the moisture adsorbent, and the core material is made of glass short fibers having an average fiber diameter of 3 to 5 μm. A vacuum heat insulating material formed by heating and pressing at 450 ° C., which is lower than the melting point, for 5 minutes is described.

JP 2006-38122 A

  However, the vacuum heat insulating material described in Patent Document 1 uses a hot press method, and the fiber diameter of glass wool is as thin as 3 to 5 μm, and the fibers are easily dissolved.

  Moreover, fibers are welded because the pressure by the press acts on the contact points between the fibers.

  Moreover, since the welded part becomes a heat path for propagating heat in the heat insulating material, the thermal conductivity of the vacuum heat insulating material is lowered.

  As described above, the fibers constituting the core material used in the conventional vacuum heat insulating material have a problem of heat propagation caused by welding and heat propagation caused by fiber breakage, that is, deterioration of heat conductivity in the vacuum heat insulating material. .

  Then, an object of this invention is to provide the vacuum heat insulating material and refrigerator which improved the heat insulation performance.

In order to solve the above problems, for example, the configuration described in the claims is adopted. The present application includes a plurality of means for solving the above-described problems. For example, a vacuum heat insulating material including a core material of a fiber assembly and a jacket material having a gas barrier property covering the core material. The average fiber diameter of the fiber assembly is 5.2 μm or less, and the thickness (mm) when a predetermined load is applied to the fiber assembly is defined as the weight (kg / m ² ) per 1 m ^{2 of the} fiber assembly. ) Is a compressive strength (mm / (kg / m ² )) that is a value divided by 24) or more.

  ADVANTAGE OF THE INVENTION According to this invention, the vacuum heat insulating material and refrigerator which improved the heat insulation performance can be provided.

It is a front view which shows the refrigerator which concerns on this embodiment. It is the sectional view on the AA line of FIG. It is a perspective view which shows a vacuum heat insulating material. It is CC sectional view taken on the line of FIG. It is a figure explaining the manufacturing method of glass fiber. It is a table | surface figure of the measurement result of Examples 1-2 of this invention and Comparative Examples 1-2. It is a figure explaining generation | occurrence | production of the wrinkle of the jacket material in a comparative example. It is a figure explaining generation | occurrence | production suppression of the flaw of the jacket material in an Example. It is a figure explaining after time progress from the state of FIG. 8A.

  Embodiments of the present invention will be described below with reference to the drawings.

(Configuration of refrigerator 1)
FIG. 1 is a front view showing a refrigerator 1 according to the embodiment. 2 is a cross-sectional view taken along line AA in FIG.

  The refrigerator 1 of the embodiment includes a refrigerating chamber 2 that cools from the top at a refrigerating temperature, an ice making (ice storage) chamber 3a that stores the ice that has been made, an upper freezing chamber (switching chamber or quick freezing chamber) 3b that cools at a freezing temperature, and a lower stage It has a freezer compartment 4 and a vegetable compartment 5 for storing vegetables.

  The refrigerator compartment doors 6a and 6b, the ice making (ice storage) compartment door 7a, the upper freezer compartment door 7b, the lower freezer compartment door 8, and the vegetable compartment door 9 are the refrigerator compartment 2, the ice making compartment 3a, the upper freezer compartment 3b, and the lower freezer compartment, respectively. 4. Open and close the front opening on the front side of each room of the vegetable room 5. A foam heat insulating material 23 and a vacuum heat insulating material 50 are disposed in each door.

  Refrigeration room doors 6a and 6b shown in FIG. 1 are doors that rotate around a hinge 10 or the like. Other ice making room doors 7a, upper freezing room doors 7b, lower freezing room doors 8 and vegetable room doors 9 include All are drawer type doors.

  When the drawer-type ice making room door 7a, the upper freezer compartment door 7b, the lower freezer compartment door 8, and the vegetable compartment door 9 are pulled out, the containers constituting each room are drawn out together with the doors.

  Each of the refrigerator compartment doors 6a and 6b, the ice making compartment door 7a, the upper freezer compartment door 7b, the lower freezer compartment door 8 and the vegetable compartment door 9 is provided with a packing for sealing between the refrigerator main body 1H (see FIG. 2). (Not shown) is attached to the outer peripheral edge of the refrigerator body 1H side.

  A partition heat insulation wall 12 is provided between the refrigerating room 2 for refrigerating temperature, the ice making (ice storage) room 3a for freezing temperature, and the upper freezing room 3b for partitioning and insulating. The partition heat insulating wall 12 is a heat insulating wall having a thickness of about 30 to 50 mm, and each of them is made of a single material such as styrofoam, foam heat insulating material (hard urethane foam), vacuum heat insulating material, or a combination of these heat insulating materials. Has been.

  The ice making chamber 3a and the upper freezing chamber 3b and the lower freezing chamber 4 are in the same freezing temperature zone and the temperature difference is the same or small, so a packing receiving surface is formed instead of a partition heat insulating wall that partitions and insulates. A partition member 13 is provided.

  A partition heat insulation wall 14 is provided between the lower freezing room 4 at the freezing temperature and the vegetable room 5 at the vegetable storage temperature to partition and insulate each. The partition heat insulation wall 14 is a heat insulation wall of about 30 to 50 mm similarly to the partition heat insulation wall 12, and is similarly made of styrofoam, foam heat insulation (hard urethane foam), vacuum heat insulation or the like. Thus, the partition heat insulation walls 12 and 14 which have heat insulation are installed in the partition of the storage room from which the storage temperature zone | band of refrigeration temperature and freezing temperature differs fundamentally.

  As shown in FIG. 2, the partition heat insulating walls 12 and 14 may be configured using a polystyrene foam 33 and a vacuum heat insulating material 50 b, and are not particularly limited.

  In addition, as shown in FIG. 1, the inside of the refrigerator main body 1H partitions and forms the storage room of the refrigerator compartment 2, the ice making room 3a, the upper freezer compartment 3b, the lower freezer compartment 4, and the vegetable compartment 5 from the top, respectively. The arrangement of the storage chambers is not particularly limited to this. Also, the refrigerator doors 6a and 6b, the ice making door 7a, the upper freezer door 7b, the lower freezer door 8, and the vegetable door 9 are not particularly limited, such as opening / closing by rotation, opening / closing by drawer, and the number of divided doors.

  The refrigerator main body 1H shown in FIG. 2 includes an outer box 21 made of a steel plate such as a PCM (Pre-Coated-Metal) steel plate, and an inner box 22 made of a resin such as ABS (Acrylonitrile Butadiene Styrene). The inner box 22 forms a refrigerator compartment 2, an ice making compartment 3a, an upper freezer compartment 3b, a lower freezer compartment 4, and a vegetable compartment 5.

  The space formed between the outer box 21 and the inner box 22 is provided with a heat insulating portion as the heat insulating space 1s to insulate each storage room and the external space in the refrigerator main body 1H.

  A vacuum heat insulating material 50 is disposed in the heat insulating space 1s between the outer box 21 and the inner box 22, and the heat insulating space 1s other than the vacuum heat insulating material 50 is filled with a foam heat insulating material 23 such as rigid urethane foam. . As will be described later, the vacuum heat insulating material 50 is fixedly supported on the outer box 21 or the inner box 22 by a fixing member, a supporting member or the like (not shown), or fixed to the outer box 21 or the inner box 22 by an adhesive.

  Further, in order to cool each room such as the refrigerator compartment 2, the ice making room 3a, the upper freezing room 3b, the lower freezing room 4, and the vegetable room 5 to a predetermined temperature, the ice making room 3a and the lower freezing room 4 are cooled on the back side. A device 28 (see FIG. 2) is provided.

  The cooler 28, the compressor 30, the condenser 31, and a capillary tube (not shown) are connected to constitute a refrigeration cycle.

  Above the cooler 28, a blower 27 that circulates the cold air cooled by the cooler 28 through the inside of the refrigerator 1 and holds it at a predetermined low temperature is disposed.

  Moreover, the recessed part 40 for accommodating the power supply board etc. in which the electrical component 41 was mounted is formed in the back part of the upper surface 1H1 of the refrigerator main body 1H shown in FIG. Various cooling operations of the refrigerator 1 and driving / stopping of various functions are controlled by a control means such as a power supply board on which the electrical component 41 is mounted. Further, a cover 42 that covers the electrical component 41 is provided above the recess 40. The height of the cover 42 is arranged so as to be substantially the same height as the top surface 1H1 of the refrigerator main body 1H in consideration of the appearance design, securing the internal volume of the refrigerator 1, and heat resistance. Although it does not specifically limit, when the height of the cover 42 protrudes outside from the top | upper surface 1H1 of the refrigerator main body 1H, it is desirable to set it in the range within 10 mm.

  Accordingly, the concave portion 40 is arranged in a state where only the concave portion 40 of the space for storing the electrical component 41 is recessed on the foamed heat insulating material 23 side (inside the warehouse). The internal volume of the refrigerator 1 is inevitably sacrificed. On the other hand, when taking the internal volume of the refrigerator 1 larger, the thickness of the foam heat insulating material 23 between the recessed part 40 and the inner box 22 will become thin. For this reason, as shown in FIG. 2, the vacuum heat insulating material 50a is arrange | positioned in the foam heat insulating material 23 which opposes the recessed part 40, and the heat insulation performance is ensured and strengthened. In this embodiment, the vacuum heat insulating material 50a is a single vacuum heat insulating material 50a formed in a substantially Z shape so as to straddle the interior lamp case (not shown) and the electrical component 41.

  Moreover, since the compressor 30 and the condenser 31 which are arrange | positioned in the machine room of the back lower part of the refrigerator main body 1H shown in FIG. 2 (lower right of the refrigerator main body 1H of FIG. 2) are components with big heat_generation | fever, In order to prevent heat from entering the box 22, the vacuum heat insulating material 50 c is disposed on the projection surface of the compressor 30 and the condenser 31 toward the inner box 22. In FIG. 2, the vacuum heat insulating material 50 is divided into a plurality of parts, but a single vacuum heat insulating material 50 c may be bent at a plurality of locations to block the heat transfer between the front of the machine room and the rear of the vegetable room 5. Good. In this case, heat transfer through a jacket material (details will be described later) of the vacuum heat insulating material 50, that is, a so-called heat bridge phenomenon is suppressed, and heat insulating performance is improved.

(Basic configuration of the vacuum heat insulating material 50)
Next, the structure of the vacuum heat insulating material 50 (50a, 50b, 50c) is demonstrated using FIG. 3, FIG. FIG. 3 is a perspective view showing a vacuum heat insulating material. 4 is a cross-sectional view taken along the line CC of FIG.

  The vacuum heat insulating material 50 includes a core material 51 for forming a vacuum space, an inner packaging material 52 for holding the core material 51 in a compressed state, an adsorbent 54 that adsorbs moisture, gas, and the like, and an inner packaging material And an outer jacket material 53 having a gas barrier layer covering the core material 51 held in a compressed state at 52. In FIG. 4, the adsorbent 54 is highlighted.

  The outer covering material 53 is disposed on both outer sides of the vacuum heat insulating material 50, and is configured in a bag shape in which portions of a certain width are bonded together by thermal welding from the outer edge of a laminate film of the same size. In addition, the bonding location 50h prevents folding back to the center side to form a heat bridge.

  About the core material 51 of the vacuum heat insulating material 50, the glass fiber of an Example whose average fiber diameter is the following is used as a laminated body of the inorganic fiber which is not adhere | attached or bound with a binder etc.

  The core material 51 is advantageous in terms of heat insulation performance because the use of a laminate of inorganic fiber materials reduces outgas (gas generation), but is not particularly limited to this. For example, ceramic fibers In addition, inorganic fibers such as rock wool, glass wool, glass fiber, alumina, silica alumina, silica, rock wool, and silicon carbide may be used. Depending on the type of the core material 51, the inner packaging material 52 may be unnecessary.

  Moreover, about the core material 51, an organic resin fiber material other than an inorganic fiber material can be used. In the case of organic resin fibers, there are no particular restrictions on the use as long as the performance as the core material 51 such as the heat resistant temperature is cleared. Specifically, polystyrene, polyethylene terephthalate, polypropylene, and the like are fiberized by the melt blown method or the spunbond method so as to have the fiber diameters of the following examples. There is no particular limitation.

The fiber assembly is preferably made of inorganic fibers or organic fibers and has a low bulk density. The compressive strength of the fiber assembly is measured as follows. The fiber assembly is cut into a predetermined size (100 mm × 100 mm), and a load is applied so as to be 25 g per 100 mm ² . After measuring the thickness (unit: mm) of the fiber assembly in a state where a load is applied, the value obtained by dividing by the basis weight (weight unit per 1 m ^{2 of the} fiber assembly: kg / m ² ) is the compressive strength (unit: mm / (kg / m ² )). The higher the compressive strength, the greater the resistance to weighting, and the core material is suitable for shape maintenance. In addition, as a method of bonding fibers, there are use of a binder agent, heat press, etc. When these methods are used, the fibers are bonded to each other to increase the compressive strength, but the point of bonding the fibers is the heat path. It is not preferable because the thermal conductivity is deteriorated.

  The fiber diameter was measured by spinning a fiber to obtain a fiber assembly, which was magnified with a microscope to obtain an average value of 30 measured values.

  In addition, in a present Example, there exist the method of performing an enlarged measurement with a microscope, and the measuring method by a micronaire measuring device. The micronaire measuring instrument is a measuring instrument for measuring the fiber fineness of cotton or the like, and measures the resistance to air flow of a certain amount of fiber lump to measure the fiber fineness. Specifically, a constant weight of fibers is stored in a sample holder so as to have a constant volume, and air of a constant pressure is blown. Then, the fiber diameter is measured in μ order by reading the air flow rate at that time.

  The fiber diameter is preferably thinner, but is preferably 10 μm or less, more preferably 5.2 μm or less in consideration of the environment and industrial productivity.

  The laminate configuration of the jacket material 53 is not particularly limited as long as it has gas barrier properties and can be thermally welded. In this embodiment, the surface (protective) layer, the first gas barrier layer, the second A laminated film having a four-layer structure of a gas barrier layer and a heat welding layer is used.

  The surface layer is a resin film that serves as a protective material, the first gas barrier layer is provided with a metal vapor deposition layer on the resin film, the second gas barrier layer is provided with a metal vapor deposition layer on a resin film having a high oxygen barrier property, The gas barrier layer and the second gas barrier layer are bonded so that the metal vapor deposition layers face each other. For the heat-welded layer, a film having low hygroscopicity was used as in the surface layer.

  Specifically, the covering material 53 includes a biaxially-stretched polypropylene, polyamide, and polyethylene terephthalate film as a surface layer, a biaxially-stretched polyethylene terephthalate film with aluminum vapor deposition as a first gas barrier layer, The gas barrier layer is made of biaxially stretched ethylene vinyl alcohol copolymer resin film with aluminum vapor deposition, biaxially stretched polyvinyl alcohol resin film with aluminum vapor deposition, or aluminum foil, and the heat-welded layer is made of unstretched polyethylene, polypropylene, etc. A film was obtained.

  The layer structure and material of the four-layer laminate film are not particularly limited to these. For example, as the first and second gas barrier layers, a metal foil or a resin-based film provided with a gas barrier film made of an inorganic layered compound, a resin-based gas barrier coating material such as polyacrylic acid, DLC (diamond-like carbon), etc. For the heat welding layer, for example, a polybutylene terephthalate film having a high oxygen barrier property may be used. The surface layer is a protective material for the first gas barrier layer, but in order to improve the vacuum exhaust efficiency in the manufacturing process of the vacuum heat insulating material 50, it is preferable to dispose a resin having a low hygroscopic property.

  In addition, resin film other than the metal foil used for the second gas barrier layer usually deteriorates the gas barrier property due to moisture absorption. In addition to suppressing the deterioration of gas barrier properties, the moisture absorption amount of the entire laminate film is suppressed. Thereby, also in the vacuum evacuation process of the vacuum heat insulating material 50 described above, the amount of moisture brought in by the jacket material 53 can be reduced, so that the vacuum evacuation efficiency is greatly improved and the heat insulation performance is improved.

  In addition, the lamination (bonding) of each film is generally performed by a dry laminating method through a two-component curable urethane adhesive that is cured by two-component reaction heat. The alignment method is not particularly limited to this, and other methods such as a wet lamination method and a thermal lamination method may be used.

  In the present embodiment, a heat-weldable polyethylene film is used for the encapsulating material 52, and a physical adsorption type synthetic zeolite is used for the adsorbent 54. However, the material is not limited to these materials. The inner packaging material 52 may be a polypropylene film, a polyethylene terephthalate film, a polybutylene terephthalate film, or the like that has low hygroscopicity and can be heat-welded and has little outgas.

  The adsorbent 54 adsorbs moisture and gas, and may be either physical adsorption or chemical reaction type adsorption. Silica gel, calcium oxide, synthetic zeolite, activated carbon, potassium hydroxide, sodium hydroxide, lithium hydroxide, etc. Can be used.

(Method for producing fiber assembly (glass fiber))
A case where fiber aggregate glass wool is used as the core material 51 used in the vacuum heat insulating material 50 will be described. Glass wool is not hardened by binder bonding or hot press, is not hardened into a board shape, has flexibility, and has resilience to the compression direction, with the inclusion material 52 (high density polyethylene as an example) Degas after packaging. The core material 51 temporarily compressed by the inner packaging material 52 is inserted into a bag-shaped outer jacket material 53 and opened, and then the inner packaging material 52 and the outer jacket material 53 are both vacuum-packed, whereby the vacuum heat insulating material 50 is obtained. Formed as. Borosilicate glass is used as the glass forming the glass wool.

Here, FIG. 5 is a figure explaining the manufacturing method of glass fiber. The molten glass G is introduced from the nozzle 101 connected to the glass melting furnace 100 toward the bottom of the hollow cylindrical rotating body 100 (spinner). The hollow cylindrical rotating body 100 rotates at a high speed around the rotating shaft 103, and the molten glass G that has been introduced rises at the side wall of the rotating body 100 by the action of centrifugal force.
Then, molten glass G is ejected from a plurality of pores 105 formed on the side wall of the rotator 100. The ejected molten glass G is heated by heating means 102 (flame radiating means such as a burner) for heating in the direction of arrow H. Here, the arrow H direction is a direction along the vertical direction of the plurality of pores 105 provided on the side wall of the rotator 100.

  Further, on the outer periphery of the discharge port of the heating unit 102 (in the vicinity of the arrowhead of the arrow H), there is a gas discharge unit 104 that is arranged concentrically around the side wall of the rotating body 100 and discharges gas continuously or at intervals. .

  In this configuration, the molten glass G discharged from the plurality of pores 105 to the outside of the rotating body 100 is formed into filament fibers. This fiber is guided in the heating direction H of the heating means 102 and progresses downward while being reduced in diameter, and the length of the fiber, the density of the fiber assembly, etc. are determined by the gas in the direction of arrow F discharged from the gas discharge means 104. Is adjusted.

  The glass fibers spun in this way are laminated so as to have a uniform density by a cotton collecting apparatus (not shown). However, as the accumulated time of spinning becomes longer, the pores 105 of the rotating body 100 gradually become larger due to friction or the like. Therefore, the fiber diameter tends to gradually increase.

  When the fiber diameter is increased, solid heat conduction is facilitated and the heat conduction resistance is reduced. And when this fiber is applied as a vacuum heat insulating material, it tends to deteriorate as heat insulation performance.

  In order to prevent the deterioration of the heat insulation performance, it is sufficient to replace the rotating body 100 with a new rotating body 100 when the pores 105 of the rotating body 100 reach a certain size. Frequent replacement is undesirable because it increases costs and impairs productivity.

  Here, in the vacuum heat insulating material 50, the porosity measuring method which is the ratio which the said space occupies among the space which becomes the vacuum state other than the core material 51 inside the inner packaging material 52 and the core material 51 in the cross section of the vacuum heat insulating material 50 Is shown below.

  First, glass wool fibers prepared to have a predetermined fiber diameter and fiber length are prepared, and a vacuum heat insulating material 50 for measuring porosity (core material size 20 × 20 × 10 t (mm) using them as a core material (core material 51). )). Next, in order to prevent the deformation of the vacuum heat insulating material 50 when observing the inside, the vacuum heat insulating material is buried in the epoxy resin, and then cut and polished to prepare a sample for measuring the porosity.

  The prepared sample was subjected to secondary electron image photographing using a scanning electron microscope (Hitachi model S-4200), image analysis was performed on the photographed secondary electron image, and the inside of the inner packaging material 52 was in a certain area. The area (space area) where the glass wool fiber does not exist is calculated as a percentage and is used as the porosity.

  The porosity of the vacuum heat insulating material of a present Example shall be 90% or more. Thereby, the heat conduction from the contact of fibers is suppressed and heat insulation performance improves.

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

Example 1
The vacuum heat insulating material 50 according to the first embodiment uses glass wool as the core material 51. Glass wool is produced by melt spinning glass. Borosilicate glass was used as the glass forming the glass wool. The glass was melted at a temperature of about 1300 ° C. in a melting furnace, and then spun by a centrifugal method using a metal rotating body 100. The spun fibers were collected on a conveyor having a suction mechanism so that the basis weight was 1400 g / m ² . The basis weight defines the weight when the collected fibers are sized to 1 m ² as can be seen from the unit. Further, in order to examine the thickness of the spun fiber, the average fiber diameter was 5.2 μm as measured with a micronaire measuring device.

  Moreover, when the length of the fiber extract | collected just under the rotary body 100 was measured, it was set to about 250 mm on the average. Furthermore, when the compressive strength was measured, it was 29.4.

The glass wool thus obtained was cut into a size of width 500 mm × length 1000 mm, dried in a drying oven at 200 ° C. for 30 minutes, and then two sheets with a basis weight of 1400 g / m ² were laminated to obtain a getter agent. (Made by Showa Union, Molecular Sieves 13X) is scattered between the layers of glass wool, placed in the outer cover material in the form of a three-sided binding bag, the inside of the bag is evacuated with a rotary pump for 10 minutes, and then with a diffusion pump After vacuuming for 10 minutes, a single part of the bag was sealed with a heat seal.

  About the obtained vacuum heat insulating material (thickness: about 12 mm), the heat insulation characteristic was measured at 10 degreeC using AUTO- (lambda) by Eihiro Seiki Co., Ltd. The heat insulating property was 200 (index). The heat insulating property is indicated by an index. The higher the heat insulating property, the better the heat insulating property.

  From this result, it was clarified that a vacuum heat insulating material having excellent heat insulating properties can be obtained.

(Example 2)
As in Example 1, the vacuum heat insulating material of Example 2 uses glass wool as the core material. When the thickness of the spun fiber was measured with a micronaire measuring device, the average fiber diameter was 4.5 μm. Moreover, when the length of the fiber extract | collected just under the rotary body 100 was measured, it was set to about 250 mm on the average. Furthermore, when the compressive strength was measured, it was 24.8.

The glass wool thus obtained was cut into a size of width 500 mm × length 1000 mm, dried in a drying oven at 200 ° C. for 30 minutes, and then two sheets with a basis weight of 1400 g / m ² were laminated to obtain a getter agent. (Made by Showa Union, Molecular Sieves 13X), put the three sides into a jacketed bag, vacuum the inside of the bag with a rotary pump for 10 minutes, then vacuum with the diffusion pump for 10 minutes, A single part of was sealed with heat seal.

  About the obtained vacuum heat insulating material (thickness: about 12 mm), the heat insulation characteristic was measured at 10 degreeC using AUTO- (lambda) by Eihiro Seiki Co., Ltd. The heat insulating property was 218 (index).

  From this result, it was clarified that a vacuum heat insulating material having excellent heat insulating properties can be obtained.

(Comparative Example 1)
In Comparative Example 1, glass wool is used as the core material as in Examples 1 and 2. When the thickness of the spun fiber was measured with a micronaire, the average fiber diameter was 6.0 μm. Moreover, when the length of the fiber extract | collected just under the rotary body 100 was measured, it was set to about 70 mm on the average. Furthermore, when the compressive strength was measured, it was 18.8.

The glass wool thus obtained was cut into a size of width 500 mm × length 1000 mm, dried in a drying oven at 200 ° C. for 30 minutes, and then laminated with two pieces having a basis weight of 1400 g / m ² to obtain a getter agent ( Combined with union Showa, Molecular Sieves 13X), put the three sides into a jacketed bag, vacuum the inside of the bag with a rotary pump for 10 minutes, then vacuum with the diffusion pump for 10 minutes, A single part was sealed with heat seal.

  About the obtained vacuum heat insulating material (thickness: about 12 mm), the heat insulation characteristic was measured at 10 degreeC using AUTO- (lambda) by Eihiro Seiki Co., Ltd. The heat insulating property was 100 (index).

  From this result, it has been clarified that the heat insulating properties are low when the fiber diameter is large and the compressive strength is low as compared with Examples 1 and 2.

(Comparative Example 2)
In Comparative Example 2, glass wool is used as the core material as in Comparative Example 1. When the thickness of the spun fiber was measured with a micronaire measuring device, the average fiber diameter was 6.8 μm. Moreover, when the length of the fiber extract | collected just under the rotary body 100 was measured, it was about 180 mm on the average. Furthermore, when the compressive strength was measured, it was 19.8.

The glass wool thus obtained was cut into a size of width 500 mm × length 1000 mm, dried in a drying oven at 200 ° C. for 30 minutes, and then laminated with two pieces having a basis weight of 1400 g / m ² to obtain a getter agent ( Combined with union Showa, Molecular Sieves 13X), put the three sides into a bag-like outer packaging material, vacuum the inside of the bag with a rotary pump for 10 minutes, vacuum with a diffusion pump for 10 minutes, The part was sealed with heat seal.

  About the obtained vacuum heat insulating material (thickness: about 12 mm), the heat insulation characteristic was measured at 10 degreeC using AUTO- (lambda) by Eihiro Seiki Co., Ltd. The heat insulating property was 126 (index).

  From this result, it has been clarified that the heat insulating properties are low when the fiber diameter is large and the compressive strength is low as compared with Examples 1 and 2.

  To summarize the above results, as shown in FIG. 6, when the fiber diameter is reduced, the thermal conductivity is also lowered, and the heat insulating performance of the vacuum heat insulating material tends to be improved.

  Further, as compared with the comparative example, if the compressive strength is small, a significant improvement in the heat insulation performance cannot be expected. Therefore, the fiber length is increased and the compressive strength is controlled to be 24 or more according to the embodiment. Thereby, the vacuum heat insulating material excellent in heat insulation can be obtained. More preferably, if it is controlled to be 24.8 or more, the heat insulation performance is further improved.

  Further, when the spinning time becomes longer, the pore diameter of the rotating body becomes larger due to friction and the like, and the diameter of the fiber to be spun tends to gradually increase. Further, when the fiber diameter is increased, the heat conduction resistance is decreased and the heat conductivity is increased. Therefore, in this embodiment, the fiber length is increased and the compressive strength is controlled to be 24 or more, so that the deterioration of the heat insulation performance can be suppressed.

  Further, by setting the compressive strength to 24 or more and the porosity to 90% or more, heat conduction at the contact point of the intertwined fibers is suppressed, and a vacuum heat insulating material having excellent heat insulating performance can be obtained.

  Next, suppression of wrinkling of the outer cover material will be described. FIG. 7 is a diagram for explaining the generation of wrinkles on the jacket material in the comparative example. FIG. 8A is a diagram illustrating the suppression of wrinkles of the outer cover material in the example. FIG. 8B is a diagram for explaining after a lapse of time from the state of FIG. 8A. In addition, the core material 51 in each figure is typically shown in order to make it easy to grasp the fiber direction.

  FIG. 7 shows a comparative example when the fiber length is short. When the fiber length of the core material 51 is short, the fiber assembly housed in the jacket material 53 has a non-uniform fiber orientation, and the fibers along the thickness direction have a considerable ratio to the fibers along the plane direction. Exists. In this case, when the pressure inside the jacket material 53 is reduced, the jacket material 53 is drawn to the core material 51 side at a position where a relatively large number of fibers extending in the thickness direction exist. Then, a collar 53a is generated in the jacket material 53 in the drawn portion. When the flange 53a is generated in the vacuum heat insulating material 50 of the comparative example, the core material 51 having a short fiber and a weak repulsive force or elastic force does not have a force to push the flange 53a back against the decompression force. Then, there is no way to repair the ridge 53a of the jacket material 53 once generated.

On the other hand, the fiber length of the example is long as shown in FIGS. 8A and 8B, and orientation along the plane direction is easily obtained. When the pressure is reduced in this configuration, as shown in FIG. 8A, the covering material 53 is partially drawn toward the core material 51 side, and the flange 53a is likely to be temporarily formed. However, the fiber assembly constituting the core material 51 has a long fiber length and orientation along the plane direction, and a compressive strength of 24 or more.
Therefore, it has a force to push the eaves 53a outward against the decompression force. Therefore, since the force which restores to the state of FIG. 8B is provided, formation of the collar 53a of the jacket material 53 can be suppressed. If wrinkles 53a of the covering material 53 are generated, cracks are generated in the portion, and the gas barrier property is lowered, and it is difficult to maintain the degree of vacuum for a long time.

  In this embodiment, since the formation of the flange 53a is suppressed, the gas barrier property of the jacket material 53 can be maintained for a long time, and the heat insulation performance can be maintained for a long time.

DESCRIPTION OF SYMBOLS 1 Refrigerator 50, 50a, 50b, 50c Vacuum heat insulating material 51 Core material 52 Inner packaging material 53 Outer covering material 53a 皺 100 Rotating body

Claims (4)

In a vacuum heat insulating material comprising a core material of a fiber assembly and a jacket material having a gas barrier property covering the core material,
The average fiber diameter of the fiber assembly is 5.2 μm or less, and the thickness (mm) when a predetermined air load is applied to the fiber assembly is the weight per 1 m ^{2 of the} fiber assembly (kg / m ² ). A vacuum heat insulating material having a compressive strength (mm / (kg / m ² )) of 24 or more, which is a value divided by.   The core material having the compressive strength is characterized by extending outwardly a ridge formed by the outer shell material being drawn into the core material side by decompression in the outer jacket material. The vacuum heat insulating material according to 1.   The vacuum heat insulating material according to claim 1 or 2, wherein a porosity of the core material is 90% or more.   In the refrigerator which arrange | positioned the vacuum heat insulating material and the foam heat insulating material between the outer box and the inner box, the said vacuum heat insulating material is a structure in the shift | offset | difference in any one of Claims 1 thru | or 3, The refrigerator characterized by the above-mentioned.