JP5548025B2 - Vacuum heat insulating material and refrigerator using the same - Google Patents

Description

The present invention relates to a vacuum heat insulating material and refrigerator using the same with improved insulation performance.

  As a social effort to prevent global warming, energy conservation is being promoted in various fields in order to control CO2 emissions. 2. Description of the Related Art In recent electrical products, particularly home appliances related to cooling and heating, those in which the heat insulating performance is enhanced by adopting a vacuum heat insulating material excellent in heat insulating properties have become mainstream from the viewpoint of reducing power consumption. In addition, in order to reduce energy consumption from various raw materials to product manufacturing processes, energy saving is promoted by promoting recycling of raw materials and reducing fuel and electricity costs in the manufacturing process. .

  As a conventional example of a vacuum heat insulating material employed in energy-saving products currently distributed in the market, there is one disclosed in Patent Document 1, but this vacuum heat insulating material uses glass wool, which is glass fiber, as a core material, It is covered with a gas barrier outer covering material, and the inside is depressurized to be in a vacuum state. Glass wool, the core material, is molded by pressing at a high temperature at which the glass fiber begins to thermally deform so that it has a constant thickness. Since the core material does not contain a binder, extra substances are generated. Thus, a vacuum heat insulating material having good heat insulating performance can be obtained. As an application example of this vacuum heat insulating material, an example in which it is used together with a urethane foam heat insulating material in a refrigerator or the like is described.

  In order to improve the heat insulation performance of the vacuum heat insulating material, many studies have been made on materials used for the vacuum heat insulating material. For example, as a material used for the core material of the vacuum heat insulating material, an example in which an inorganic powder material is compression-molded (Patent Document 2), a urethane foam panel in which holes are connected (Patent Document 3), or Examples of organic and inorganic fiber laminates (Patent Document 4) are mentioned. In addition, with regard to the outer packaging material, a metal container (Patent Document 5), a plastic film laminate film, a material having a metal layer such as aluminum foil, and a vapor deposition layer such as aluminum vapor deposition are provided. Many types of configurations have been studied and applied, including material selection and laminate layer number selection, such as those (Patent Document 6). Further, many adsorbents for reducing moisture and gas in vacuum have been studied including physical adsorbents and chemical adsorbents.

Japanese Patent Laid-Open No. 2005-220954 JP 61-144492 A JP-A-10-169889 Japanese Patent No. 4012903 JP-A-61-66069 JP 2008-256125 A

Through the above-mentioned background, as a structure widely applied as a high performance vacuum insulation panel at present, a plastic laminate film of 3 to 4 layers in which a laminated body of glass wool as a core material and an aluminum foil or an aluminum vapor deposition layer as an outer packaging material is arranged. As the adsorbent, quick lime, molecular sieve 13X and the like are generally used.
Under such circumstances, the decline in thermal conductivity, which is the heat insulation performance of vacuum insulation materials, has reached its peak, but energy-saving competition for refrigerators, etc. is severe, and high performance of vacuum insulation materials is indispensable Technology.

In view of the above circumstances, and an object thereof is to provide a refrigerator using the same heat insulating performance higher cost of the vacuum heat insulating material and.

In order to achieve the above object, the vacuum heat insulating material according to the first aspect of the present invention is formed so that the fiber diameter of the inorganic or organic fiber laminate is 3 μm or more and 8 μm or less on average and the fiber length is 2 mm or more and 10 mm or less on average. A vacuum heat insulating material having a core material that does not use a binder and a gas barrier film that covers the core material, wherein the vacuum heat insulating material has a porosity of 80% or more in its extending direction cross section. and 85% or less, and the less than 100% der porosity is 85% or more of the cross section in the thickness direction is adiabatic direction is, Young's modulus of the fibers forming the fiber layer which is used as the core material Is 75 MPa or more and 85 MPa or less, the raw material of the fiber forming the fiber laminate used as the core material does not contain boron, and the thermal conductivity is 1.0 to 1.1 mW / mK .

The refrigerator according to the second aspect of the present invention includes a heat insulating box body in which at least the vacuum heat insulating material according to the first aspect of the present invention is installed in a space formed between an outer box that forms an exterior and an inner box that accommodates stored items . It is provided.

According to the present invention, the refrigerator can be realized using the same heat insulating performance higher cost of the vacuum heat insulating material and.

It is a front view which shows the refrigerator which concerns on this embodiment. (a) is the sectional view on the AA line of FIG. 1, (b) is the B section enlarged view of (a). (a) is a perspective view which shows a vacuum heat insulating material, (b) is CC sectional view taken on the line of (a). It is the figure which showed the position cut | disconnected when measuring the porosity of a vacuum heat insulating material at the time of placing a vacuum heat insulating material on a horizontal surface.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
FIG. 1 is a front view showing a refrigerator 1 according to the embodiment. 2A is a cross-sectional view taken along the line AA in FIG. 1, and FIG. 2B is an enlarged view of a portion B in FIG. 2A.
The refrigerator 1 according to the embodiment includes a refrigerator compartment 2 that cools at a refrigerator temperature from above, an ice making (ice storage) chamber 3a for storing ice-formed ice, an upper freezer compartment (switching chamber) 3b that cools at a freezing temperature, and a lower freezer compartment 4, It has 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.
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 sealed to the refrigerator body 1H (see FIG. 2 (a)). The packing (not shown) is attached to the outer peripheral edge of the refrigerator main body 1H side.
A partition heat insulation wall 12 is provided between the refrigerating room 2 for refrigerating temperature and the ice making (ice storage) room 3a and the upper freezing room 3b for refrigerating temperature to partition and insulate them. The partition heat insulating wall 12 is a heat insulating wall having a thickness of about 30 to 50 mm, and each of them may be used alone or in combination with a plurality of heat insulating materials such as styrofoam, foam heat insulating material (hard urethane foam), vacuum heat insulating material, etc. Is formed.

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 room from which the storage temperature zone | band of refrigeration temperature and freezing temperature differs fundamentally.
As shown in FIG. 2A, the partition heat insulating walls 12 and 14 may be configured using a foamed polystyrene 33 and a vacuum heat insulating material 50b, 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.

A refrigerator main body 1H shown in FIG. 2A 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) resin. Yes. 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.

In addition, 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, a cooler is provided on the back side of the ice making room 3a and the lower freezing room 4. 28 (see FIG. 2A).
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 for controlling the operation | movement of the refrigerator 1 is mounted is formed in the rear part of the top | upper surface 1H1 of the refrigerator main body 1H shown to Fig.2 (a). A cover 42 (see FIG. 2B) covering the electrical component 41 is provided. 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 appearance design and securing the internal volume of the refrigerator 1. 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 recess 40 is arranged in a state where only the recess 40 of the space for storing the electrical component 41 is recessed on the foam insulation 23 side (inside of the warehouse). The internal volume of the refrigerator 1 is inevitably sacrificed. On the other hand, when the internal volume of the refrigerator 1 is increased, the thickness of the foam heat insulating material 23 between the recess 40 and the inner box 22 is reduced. For this reason, as shown in FIG.2 (b), 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. In addition, the cover 42 is made of a steel plate having fire resistance, and prevents igniting from the outside and ignition for some reason.

  Moreover, since the compressor 30 and the condenser 31 which are arrange | positioned at the back lower part of the refrigerator main body 1H shown to Fig.2 (a) (lower right of the refrigerator main body 1H of Fig.2 (a)) are components with big heat_generation | fever, In order to prevent heat from entering the inner box 22, a vacuum heat insulating material 50 c is arranged on the projection surface of the compressor 30 and the condenser 31 toward the inner box 22.

<Vacuum insulation 50>
Next, the structure of the vacuum heat insulating material 50 (50a, 50b, 50c) is demonstrated using FIG. Fig.3 (a) is a perspective view of the vacuum heat insulating material 50, FIG.3 (b) is CC sectional view taken on the line of Fig.3 (a). Note that the adsorbent 54 is highlighted in 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.

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 thermal bridge.
For the core material 51 of the vacuum heat insulating material 50, glass wool having an average fiber diameter of 4 μm is used as a laminate of inorganic fibers that are not bonded or bound by a binder or the like.
About the core material 51, since outgas (gas generation) decreases by using the laminated body of an inorganic fiber material, it is advantageous in terms of heat insulation performance. Or inorganic fibers such as glass fibers other than rock wool and glass wool 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, it is common to fiberize polystyrene, polyethylene terephthalate, polypropylene, etc. to a fiber diameter of about 1 to 30 μm by a melt blown method or a spunbond method, If it is a fiberization method, it will not specifically limit.
The laminate structure 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 gas barrier layer 1, the gas barrier layer 2, the heat A laminate film having a four-layer structure of welding layers is used.

The surface layer is a resin film serving as a protective material, the gas barrier layer 1 is provided with a metal vapor deposition layer on the resin film, the gas barrier layer 2 is provided with a metal vapor deposition layer on a resin film having a high oxygen barrier property, and the gas barrier layer 1 and the gas barrier layer. 2 is 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 film of polypropylene, polyamide, polyethylene terephthalate, etc. as a surface layer, a biaxially stretched polyethylene terephthalate film with aluminum vapor deposition as a gas barrier layer 1, and an aluminum as a gas barrier layer 2. A biaxially stretched ethylene vinyl alcohol copolymer resin film with vapor deposition, a biaxially stretched polyvinyl alcohol resin film with aluminum vapor deposition, or an aluminum foil was used, and the heat-welded layer was a film of unstretched polyethylene, polypropylene, or the like.

  The layer structure and material of the four-layer laminate film are not particularly limited to these. For example, as gas barrier layers 1 and 2, a metal foil or a resin film provided with a gas barrier film made of an inorganic layered compound, a resin gas barrier coating material such as polyacrylic acid, DLC (diamond-like carbon), or the like, or heat-sealed For example, a polybutylene terephthalate film having a high oxygen barrier property may be used for the layer. The surface layer is a protective material for the gas barrier layer 1, but in order to improve the evacuation 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, since the resin barrier film other than the metal foil used for the gas barrier layer 2 generally deteriorates the gas barrier property when it absorbs moisture, the gas barrier can be obtained by arranging a resin having a low hygroscopic property for the heat-welded layer. This suppresses the deterioration of the property and suppresses the moisture absorption amount of the entire laminate film. 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 lamination 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.

<Method for measuring porosity of vacuum heat insulating material 50>
In the vacuum heat insulating material 50 manufactured as described above, the space that is the proportion of the space in the vacuum state other than the core material 51 and the core material 51 inside the inner packaging material 52 in the cross section of the vacuum heat insulating material 50 occupies the space. The method for measuring the rate 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 (core material size 20 × 20 × 10 t (mm) for porosity measurement using them as a core material (core material 51). )). Next, in order to prevent the shape 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), and the obtained secondary electron image was subjected to image analysis, so that the inside of the inner packaging material 52 was in a certain area. The area (space area) where no glass wool fiber was present was calculated as a percentage and used as the porosity.
The cutting position of the vacuum heat insulating material 50 is shown in FIG. FIG. 4 is a diagram showing a position to be cut when measuring the porosity of the vacuum heat insulating material 50. In FIG. 4, the adsorbent 54 is highlighted.
In FIG. 4, the DD cross section of the vacuum heat insulating material 50, that is, the cross section in the extending direction, which is the direction in which the vacuum heat insulating material 50 spreads, is referred to as “horizontal direction” and is the heat insulating direction that blocks the heat of the vacuum heat insulating material 50. The EE cross section in the thickness direction is referred to as “cross section direction” below.

The Young's modulus of the glass fiber forming the core material (core material 51) is measured by the following means. In each of Embodiments 1 to 6 and Comparative Examples 1 to 3, glass wool is pulverized, put in a platinum crucible and melted at 1700 ° C., and then poured into a graphite mold to produce a glass block. In order to remove distortion, the produced block was heated again to 550 ° C., then cooled to 300 ° C. at 4 ° C. per minute, and then cooled to room temperature in the furnace. The glass block from which the strain was removed was cut into a size of 4 × 3 × 40 mm using a cutting machine, and then the surface was polished (JIS B 0601 0.8S or less) to obtain a sample for Young's modulus measurement. The Young's modulus was measured by an ultrasonic method using a burst wave sound velocity measuring device (model: RAM-5000 type) manufactured by RITEC. The ultrasonic method is a method for obtaining the Young's modulus of a solid from the velocity of the transverse wave and longitudinal wave of the ultrasonic wave transmitted in the solid.
Moreover, the thermal conductivity of each vacuum heat insulating material was measured. Eihiro Seiki's auto lambda HC-074-630 was used for the measurement, and it was decided to compare the measured values with the sensor in the center.

Hereinafter, the measurement result measured by the above-mentioned method of Embodiments 1-6 and Comparative Examples 1-3 is demonstrated.
In Table 1, the measured value of Embodiments 1-6 measured by the above-mentioned method and Comparative Examples 1-3 is shown.

(Embodiment 1)
The physical properties of the core material 51 of the vacuum heat insulating material 50 were measured by the above-described method. As a result, the porosity of the vacuum heat insulating material 50 in the horizontal direction (extending direction cross section) was 85% and the cross section direction (thickness direction cross section). The porosity was 86%. The Young's modulus indicating the strength and repulsive force of the core material 51 was 77 MPa (megapascal).
With respect to the vacuum heat insulating material 50, when the thermal conductivity of the central portion was measured for a size of 500 × 1500 × 10 mm, the thermal conductivity was 1.1 m (mm) W / m · K, which was a low value.

  According to the first embodiment, the vacuum heat insulating material 50 has a horizontal porosity (cross section in the extending direction) of 85%, a cross sectional direction (cross section in the thickness direction) of 86%, and the Young's modulus of the core material 51 is 77 MPa. Thus, a vacuum heat insulating material 50 having high heat insulating performance was obtained.

(Embodiment 2)
The various properties of the core material 51 of the vacuum heat insulating material 50 were measured by the above-mentioned method. As shown in Table 1, the horizontal direction (extending direction cross section) porosity of the vacuum heat insulating material 50 was 83%, the cross-sectional direction. The porosity of (thickness direction cross section) was 91%. The Young's modulus of the core material 51 was 78 MPa. With respect to the vacuum heat insulating material 50, when the thermal conductivity of the central portion was measured for a size of 500 × 1500 × 10 mm, the thermal conductivity was as low as 1.0 mW / m · K, which was a favorable value.

  According to the second embodiment, the vacuum heat insulating material 50 has a horizontal porosity (cross section in the extending direction) of 83%, a cross sectional direction (thickness direction cross section) of 91%, and the core 51 has a Young's modulus of 78 MPa. Thus, the vacuum heat insulating material 50 having high heat insulating performance was obtained.

(Embodiment 3)
When various properties of the core material 51 of the vacuum heat insulating material 50 were measured by the above-described methods, as shown in Table 1, the horizontal porosity of the vacuum heat insulating material 50 was 80%, and the porosity in the cross-sectional direction was 85%. Met. Moreover, the Young's modulus of the core material 51 was 75 MPa. With respect to the vacuum heat insulating material 50, when the thermal conductivity of the central portion was measured for a size of 500 × 1500 × 10 mm, the thermal conductivity was as low as 1.0 mW / m · K, which was a favorable value.

  According to the third embodiment, the vacuum heat insulating material 50 has a porosity in the horizontal direction (cross section in the extending direction) of 80%, a porosity in the cross section direction (cross section in the thickness direction) of 85%, and a Young's modulus of the core material 51 of 75 MPa. Thus, the vacuum heat insulating material 50 having high heat insulating performance was obtained.

(Embodiment 4)
When various properties of the core material 51 of the vacuum heat insulating material 50 were measured by the above-described method, as shown in Table 1, the horizontal porosity of the vacuum heat insulating material 50 was 82%, and the porosity in the cross-sectional direction was 92%. Met. The Young's modulus of the core material 51 was 80 MPa. With respect to the vacuum heat insulating material 50, when the thermal conductivity of the central portion was measured for a size of 500 × 1500 × 10 mm, the thermal conductivity was as low as 1.0 mW / m · K, which was a favorable value.
According to the fourth embodiment, the vacuum heat insulating material 50 has a horizontal porosity (cross section in the extending direction) of 82%, a cross sectional direction (thickness direction cross section) of 92%, and the core 51 has a Young's modulus of 80 MPa. Thus, the vacuum heat insulating material 50 having high heat insulating performance was obtained.

(Embodiment 5)
The physical properties of the core material 51 of the vacuum heat insulating material 50 were measured by the above-described methods. As shown in Table 1, the vacuum heat insulating material 50 had a horizontal porosity of 84% and a cross-sectional porosity of 90%. Met. The Young's modulus of the core material 51 was 79 MPa. With respect to the vacuum heat insulating material 50, when the thermal conductivity of the central portion was measured for a size of 500 × 1500 × 10 mm, the thermal conductivity was as low as 1.0 mW / m · K, which was a favorable value.

  According to the fifth embodiment, the vacuum heat insulating material 50 has a horizontal porosity (cross section in the extending direction) of 84%, a cross sectional direction (thickness direction cross section) of 90%, and the core material 51 has a Young's modulus of 79 MPa. Thus, the vacuum heat insulating material 50 having high heat insulating performance was obtained.

(Embodiment 6)
When various properties of the core material 51 of the vacuum heat insulating material 50 were measured by the above-described method, as shown in Table 1, the horizontal porosity of the vacuum heat insulating material 50 was 81%, and the porosity in the cross-sectional direction was 88%. Met. The Young's modulus of the core material 51 was 77 MPa. With respect to the vacuum heat insulating material 50, when the thermal conductivity of the central portion was measured for a size of 500 × 1500 × 10 mm, the thermal conductivity was as low as 1.0 mW / m · K, which was a favorable value.
According to the sixth embodiment, the vacuum heat insulating material 50 has a horizontal porosity (cross section in the extending direction) of 81%, a cross sectional direction (cross section in the thickness direction) of 88%, and a Young's modulus of the core material 51 of 77 MPa. Thus, the vacuum heat insulating material 50 having high heat insulating performance was obtained.

In addition, about the said Embodiments 1-6, all are prepared so that a boric acid component may not be contained using the glass raw material of 100% of recycled glass, an average fiber diameter is 3 micrometers or more and 8 micrometers or less, and an average fiber length is 2 mm. It adjusted so that it might become 10 mm or less above. In addition, about a fiber diameter, it is based on the measuring method of the average thickness of the fiber by JIS A 9504; artificial mineral fiber heat insulating material. Here, 100% recycled glass is most desirable from the viewpoint of cost reduction and resource protection, but 95 to 99% recycled glass may be used.
About the measurement of fiber length distribution, a glass fiber is heated at the temperature of about 400-500 degreeC, and an impurity is burned off. Thereafter, a part of the glass fiber was uniformly dispersed in the liquid, and the fiber length was measured for the total number of glass fibers.

  From the results of Embodiments 1 to 6 and Comparative Examples 1 to 3 to be described later, the porosity of the vacuum heat insulating material 50 in the horizontal direction (cross section in the extending direction) is 80% or more and 85% or less, and the cross section of the vacuum heat insulating material 50 In order to improve the heat insulation performance of the vacuum heat insulating material 50, the porosity in the direction (cross section in the thickness direction) is preferably 85% or more and less than 100%. Further, the Young's modulus of the fibers forming the inorganic or organic fiber laminate used as the core material 51 of the vacuum heat insulating material 50 is 75 MPa or more and 85 MPa or less, so that the heat insulating performance of the vacuum heat insulating material 50 is improved. It is preferable in terms of improvement.

<Effects of Embodiments 1 to 6>
According to Embodiments 1 to 6, since the fiber length is in the optimum range of 2 mm or more and 10 mm or less, the fiber orientation is improved. For example, unlike the first to sixth embodiments described above, if the fiber length is short, the fibers tend to stand up, and the ratio of fibers parallel to the thickness direction of the vacuum heat insulating material 50 (the vertical direction of the vacuum heat insulating material 50 in FIG. 4). Becomes larger. In that case, a path for transferring heat from the front surface 50o of the vacuum heat insulating material 50 to the back surface 50u or a path for transferring heat from the back surface 50u of the vacuum heat insulating material 50 to the front surface 50o, that is, fibers parallel to the thickness direction increase. , The heat insulation performance deteriorates.

In addition, by optimizing the fiber diameter to be thin, the volume occupied by the fibers in the inner packaging material 52 is reduced, and the porosity in the vacuum heat insulating material 50 (ratio of the volume occupied by the vacuum with high heat insulating properties) is improved. Thereby, the thermal conductivity of the vacuum heat insulating material 50 can be reduced, and the heat insulating performance of the vacuum heat insulating material 50 is improved.
Also, when using waste glass cullet (pulverized product), it is usually prepared by adding additives such as boric acid, ensuring fiber stretchability during spinning, fiber diameter reduction and orientation To improve. On the other hand, by securing the fiber length and porosity as in the first to sixth embodiments, it becomes possible to fiberize the waste glass such as recycled glass by 95 to 100%, which also has the effect of reducing the material cost. Can be obtained. In addition, resources can be reduced.

Further, by adjusting the orientation of the fibers of the core material 51 and setting the porosity to the above-described predetermined value, an additive such as boric acid is not necessary, and the cost can be reduced.
Moreover, by installing the vacuum heat insulating material 50 in the inner box 22 or the outer box 21 using an adhesive and a fixing member, the heat insulating performance of the refrigerator 8 is improved, and power saving can be achieved.
As described above, the heat insulating performance of the refrigerator 8 using the vacuum heat insulating material 50 is improved, the heat insulating performance is excellent, and the low cost vacuum heat insulating material 50 with less power consumption, the refrigerator main body (heat insulating box) 1H using the same, and The refrigerator 1 can be provided.

Here, the waste glass includes glass fiber used as the core material 51 of the vacuum heat insulating material 50, and also includes generally used glass material waste such as bottles.
In addition, by not containing boron in the raw material of the fiber forming the inorganic or organic fiber laminate used as the core material 51 of the vacuum heat insulating material 50, outgas (gas generation) and generation of moisture are suppressed. it can. Therefore, the vacuum state of the vacuum heat insulating material 50 can be maintained, and deterioration of the heat insulating performance of the vacuum heat insulating material 50 can be suppressed.
In the first to sixth embodiments, the fired heat insulating material 23 has been described as an example of the heat insulating material, but an appropriately selected heat insulating material other than the fired heat insulating material may be used.

Next, about Comparative Examples 1-3, the result measured by the said method is demonstrated compared with Embodiment 1-6.
(Comparative Example 1)
The various properties of the core material of the vacuum heat insulating material of Comparative Example 1 were measured by the above method. As shown in Table 1, the porosity of the vacuum heat insulating material in the horizontal direction (cross section in the extending direction of the vacuum heat insulating material) was The porosity in the cross-sectional direction (the cross section in the thickness direction of the vacuum heat insulating material) was 75%. The Young's modulus of the core material was 90 MPa. About this vacuum heat insulating material, when the heat conductivity of the center part was measured about the size of 500x1500x10mm, it is 1.7 mW / m * K and the heat conductivity 1 of the vacuum heat insulating material 50 of Embodiment 1-6 is 1. Compared to 0.0 to 1.1 mW / m · K, the value was bad. That is, since the vacuum heat insulating material of Comparative Example 1 has higher thermal conductivity than the vacuum heat insulating materials 50 of Embodiments 1 to 6, the heat insulating performance of the vacuum heat insulating material is inferior.

Regarding the cause of this, first, since the void ratio in the horizontal direction is too low, it is presumed that the fiber direction is not horizontal and there are many fibers standing in the thickness direction of the vacuum heat insulating material. Therefore, it is considered that heat transmitted through the fibers in the thickness direction of the vacuum heat insulating material is large and heat conduction in the thickness direction is increased, resulting in poor heat insulation performance.
Moreover, since the Young's modulus of a core material is comparatively large compared with 90 MPa and Young's modulus 75-80 MPa of Embodiments 1-6, it is estimated that the core material of the vacuum heat insulating material of Comparative Example 1 is in a hard fiber state. Is done. Therefore, it is inferred that the fibers of the core material are not able to withstand the pressure in the process from the reduced pressure during the production of the vacuum heat insulating material of Comparative Example 1 to the atmospheric pressure load, and the orientation of the fibers tends to deteriorate. Is done.

(Comparative Example 2)
About various physical properties of the core material of the vacuum heat insulating material of the comparative example 2, when measured by the above method, as shown in Table 1, the porosity of the vacuum heat insulating material in the horizontal direction (cross section in the extending direction of the vacuum heat insulating material) is The porosity in the cross-sectional direction (cross section in the thickness direction of the vacuum heat insulating material) was 79% and 83%. The Young's modulus of the core material was 73 MPa. About this vacuum heat insulating material, when the heat conductivity of the center part was measured about the size of 500x1500x10mm, it was 1.4mW / m * K and was the same value as the past like the comparative example 3 of the postscript. .

The heat conductivity of 1.4 mW / m · K of the vacuum heat insulating material of Comparative Example 2 is higher than the heat conductivity of 1.0 to 1.1 mW / m · K of the vacuum heat insulating material 50 of Embodiments 1 to 6. High conductivity. Therefore, the heat insulating performance of the vacuum heat insulating material of Comparative Example 2 is inferior to that of the vacuum heat insulating materials 50 of the first to sixth embodiments.
The reason why the thermal conductivity of Comparative Example 2 is high is that the porosity in the horizontal direction (cross section in the extending direction of the vacuum heat insulating material) is low and the fiber direction is not horizontal, and many fibers are standing in the thickness direction (insulating direction). I guess that. Therefore, heat is transmitted through the fibers standing in the thickness direction of the vacuum heat insulating material, heat conduction in the thickness direction is increased, and it is estimated that the heat insulating performance is inferior.

(Comparative Example 3)
The physical properties of the core material of the conventional vacuum heat insulating material of Comparative Example 3 were measured by the above method. As shown in Table 1, the horizontal space of the vacuum heat insulating material (cross section in the extending direction of the vacuum heat insulating material) The porosity was 90%, and the porosity in the cross-sectional direction (cross section in the thickness direction of the vacuum heat insulating material) was 90%. The Young's modulus of the core material was 70 MPa. About this vacuum heat insulating material, when the heat conductivity of the center part was measured about the size of 500x1500x10mm, it was 1.5 mW / m * K.

  The heat conductivity of the vacuum heat insulating material of Comparative Example 3 is 1.5 mW / m · K, which is higher than the heat conductivity of 1.0 to 1.1 mW / m · K of the vacuum heat insulating material 50 of Embodiments 1 to 6. The rate is high and heat is easily transmitted. Therefore, it can be seen that the heat insulating performance of the vacuum heat insulating material of Comparative Example 3 is inferior to that of the vacuum heat insulating materials 50 of the first to sixth embodiments.

1 refrigerator 1H refrigerator body (insulation box)
2 Cold room 3a Ice making room (freezer room)
3b Upper freezer room (freezer room)
4 Lower freezer compartment (freezer compartment)
5 Vegetable room 12 Partition insulation wall (first partition member)
14 Partition insulation wall (second partition member)
21 Outer box 22 Inner box 23 Foam insulation (insulation)
50, 50a, 50b, 50c Vacuum heat insulating material 51 Core material 53 Jacket material (gas barrier member)

Claims (3)

An inorganic or organic fiber laminate having an average fiber diameter of 3 μm or more and 8 μm or less and a fiber length of 2 mm or more and 10 mm or less on average; a core material that does not use a binder; and a gas barrier film that covers the core material; A vacuum insulation material having
The vacuum heat insulating material has a void ratio in the extending direction cross section that is the spreading direction of 80% or more and 85% or less, and a void ratio of the thickness direction cross section that is the heat insulating direction is 85% or more and less than 100%. Oh it is,
The Young's modulus of the fibers forming the fiber laminate used as the core material is 75 MPa or more and 85 MPa or less,
It does not contain boron in the raw material of the fiber forming the fiber laminate used as the core material,
A vacuum heat insulating material having a thermal conductivity of 1.0 to 1.1 mW / mK . The vacuum heat insulating material according to claim 1 , wherein the raw material of the fiber forming the fiber laminate used as the core material has a waste glass cullet of 95% or more and 100% or less. A space formed between an outer box that forms an exterior and an inner box that stores a stored item is provided with a heat insulating box body in which at least the vacuum heat insulating material according to claim 1 or 2 is installed. Refrigerator.

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