JP2011002033A - Vacuum heat insulating material, and heat insulating box and refrigerator using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress reduction of heat insulating performance and the occurrence of poor leakage by improving slidability for an outer coating material of a core material so as to alleviate stress concentration on a bend portion of the outer coating material and minimize shrinkage of the outer coating material and the occurrence of wrinkles in the bend portion when a vacuum heat insulating material is bent.SOLUTION: The vacuum heat insulating material includes a core material of a plurality of laminated bodies containing a fiber of long fiber web, and an outer coating member having gas barrier property. The core material is composed of the plurality of laminated bodies each having a fiber containing at least a resin fiber of a different friction coefficient for each laminated body. By changing a condition of the surface of the resin fiber, a friction coefficient of the core material and the innermost layer of the outer coating material contacted with the core material is provided to be smaller than a friction coefficient of core materials having different friction coefficients. Accordingly, the stress applied on the bend portion is alleviated when the vacuum heat insulating material is bent. The core material different in friction coefficient for each laminated body a plurality of laminated bodies formed by melt spinning of a melt-blown method using resin or a spun-bonding method.

Description

  The present invention relates to a vacuum heat insulating material capable of improving a heat insulating / cooling function, a heat insulating box using the same, a refrigerator, and the like.

  Since the heat conductivity of the vacuum heat insulating material is an order of magnitude lower than that of the urethane foam material conventionally used in refrigerators, the amount of use is increasing as heat insulating materials for refrigerators, bathtubs, thermos bottles, and the like. However, since the vacuum heat insulating material is a composite material composed of a vacuumed core material and an outer packaging material, there is a problem that it is difficult to bend into an arbitrary three-dimensional shape. In order to improve this problem, conventionally, as a shape of the vacuum heat insulating material before bending, a groove shape is processed in advance, and bending is performed along this groove, for example, Patent Document 1 and Patent Document 2 And Patent Document 3 proposed.

JP 2004-11755 A JP-A-7-151297

  In order to improve the heat insulating performance of a heat insulating device such as a refrigerator, it is necessary to increase the installation area of the vacuum heat insulating material having a low thermal conductivity. However, since the vacuum heat insulating material is a composite material composed of a core material and an outer covering material (also referred to as an outer packaging material), bending molding is difficult.

  As disclosed in Patent Documents 1 and 2 above, when bending is performed by processing a groove shape in only one direction on the vacuum heat insulating material in order to perform bending, bending can be performed only in one direction. There is a problem that heat from the portion where the thickness is reduced leaks due to the thickness of the groove portion being reduced. Further, by performing bending molding, a load is applied to the jacket material, which may lead to vacuum breakage or long-term vacuum breakage (slow leak). Furthermore, there is a problem that the heat insulation performance is deteriorated due to the fibers of the core material being cut by compression processing of the vacuum heat insulating material in the groove forming.

  The present invention reduces the stress concentration at the bent portion of the jacket material at the bent portion when the vacuum heat insulating material is bent, reduces the shrinkage of the jacket material and the generation of wrinkles, and causes the occurrence of leakage defects and heat insulation. It is an object to suppress a decrease in performance.

In order to solve the above problems, the present invention mainly adopts the following configuration.
A vacuum heat insulating material comprising a core material composed of a plurality of laminates having fibers of a long fiber web, and an outer jacket material having gas barrier properties, wherein the core material has at least different friction coefficients in each laminate. It is a multi-layered body having fibers including resin fibers, and by manipulating the surface state of the resin fibers, the friction coefficient between the core material and the innermost layer of the jacket material in contact with the core material, the friction coefficient The cores are different from each other in friction coefficient, and the stress at the bending portion when the vacuum heat insulating material is bent is reduced.

  Further, in the vacuum heat insulating material, the core material having a different friction coefficient in each laminated body is a plurality of laminated bodies formed by melt spinning using a resin melt blow method or a spun bond method. Further, the difference in the friction coefficient between the laminates having different friction coefficients is 0.1 or more and less than 1.0.

  According to the present invention, when the vacuum heat insulating material is bent, the slip of the core material with respect to the innermost layer of the outer cover material is improved, and the stress concentration at the bent portion of the outer cover material is alleviated. Therefore, it is possible to prevent the outer cover material from being perforated. Therefore, as a result, it is possible to realize bending molding of an arbitrary three-dimensional shape of the vacuum heat insulating material.

  In addition, the surface condition of the core fiber that comes into contact with the jacket material at the time of preparing the core material is processed to reduce the friction coefficient so that it is different from the normal state. In that case, as a manufacturing method at the time of fiberization Since the spun bond method, the melt blow method, or the like is used, the resin to be used is not limited to the virgin resin, and may be a recycled resin. Therefore, cost reduction and environmental load reduction can be achieved.

It is sectional drawing of the vacuum heat insulating material which concerns on embodiment of this invention. It is sectional drawing of the vacuum heat insulating material regarding a prior art. It is sectional drawing of the heat insulation box provided with the vacuum heat insulating material which concerns on this embodiment. It is a longitudinal cross-sectional view of the refrigerator provided with the vacuum heat insulating material which concerns on this embodiment. It is a figure explaining the bending test content of the vacuum heat insulating material which concerns on this embodiment. It is a figure which shows the result of the comparison test content of the various Examples in the vacuum heat insulating material which concerns on this embodiment, a prior art example, and a comparative example.

    Regarding the characteristics of the vacuum heat insulating material according to the embodiment of the present invention, the conceptual configuration, function, and effect will be described below with reference to the drawings. The vacuum heat insulating material according to the embodiment of the present invention includes a resin fiber, an adsorbent, and a jacket material. The jacket material is sealed under reduced pressure, and the resin fiber is an environmentally friendly long fiber web. Is provided. The core material of the vacuum heat insulating material has a function of a spacer that maintains its shape from atmospheric pressure, and is preferably a fiber having high voids even when subjected to compressive stress during decompression. In addition, since the thermal conductivity, which is an index of heat insulation performance, varies greatly depending on the type of core material, an inexpensive general-purpose product and a highly rigid fiber body having low hygroscopicity were selected as the core material.

  The resin used in this embodiment is preferably a molecular chain that is rigid, difficult to entangle, is brittle, and has a flexural modulus of about 3000 MPa or more. Polystyrene, which is a general-purpose product, is particularly preferable. Polystyrene has a hydrophobic nonpolar group, has a low hygroscopic property, and the molecular weight is not limited as long as it is fiberized, and is preferably about 200,000 to 400,000. For example, when general-purpose polyethylene or polypropylene fibers are used instead of polystyrene fibers, the hygroscopicity is low, but the flexural modulus is low and the creep phenomenon is large. Thermal insulation performance is inferior compared to polystyrene with a rate of 5 mW / m · K or more, but it shows thermal insulation performance about 5 times that of hard polyurethane resin, which was a conventional thermal insulation material, thereby improving coverage by bending. Considering it, there is no obstacle to its adoption.

  As the state of the fiber, if the length is short as a short fiber and the heat conductivity is high, the continuous fiber (continuous indefinite length fiber) and the average fiber diameter are about 20 μm. Hereinafter, 5 to 20 μm is particularly preferable from the viewpoint of thermal conductivity. For example, the stiffness of the fiber is proportional to the product of the fourth power of the fiber diameter and the Young's modulus. Therefore, when the major axis is halved, the stiffness is reduced to 1/16 and becomes very soft and about 5 μm or more. preferable. On the contrary, if the fiber diameter is too large, the contact of the fiber becomes close to a line, the thermal conductivity is increased by reducing the contact thermal resistance, and is preferably about 20 μm or less.

In addition, the average fiber diameter measured the fiber diameter of the visual field containing about 10 fibers using the scanning electron microscope. Furthermore, when the density of the core material is 150 kg / m ³ or less, the strength of the core material decreases and the thermal conductivity tends to increase. On the contrary, if it is 300 kg / m ³ or more, it becomes heavier and the thermal conductivity becomes higher from the viewpoint of porosity and the like. That is, if the density of the core material is too light or too heavy, the heat insulating property tends to be lowered, and the preferred density is 150 to 300 kg / m ³ at the average fiber diameter. The density of the core material is the density after evacuation accommodated in the jacket material, and the weight of the jacket material and the adsorbent is subtracted from the weight of the vacuum insulation material, and from the weight of the core material and the volume of the vacuum insulation material. Density was calculated.

  The organic fiber aggregate is formed by a long fiber web formed by melt spinning a resin, directly extruding from a nozzle and drawing. For example, polystyrene fibers are spun at an extrusion temperature of about 200 to 320 ° C., and when the temperature is low, the extrusion torque increases. The long fiber aggregate is preferably a core material that is not adhesively bonded by thermal bonding, needle punching, or the like, and is formed and collected so as to produce an oriented web. Specifically, a polystyrene resin is extruded from the tip of a nozzle by a melt blown, fibers are drawn by air injection, and collected on a collector to form a web. In spunbonding, a web is formed in the same manner by continuously extruding from a plurality of spinning nozzle tips and collecting fibers from an ejector on a collector by jetting air. The fiber shape is not limited to a circle, and may be a substantially circular shape, a substantially Y shape, a substantially elliptical shape, a substantially star shape, a substantially polygonal shape, or the like. Can provide a fiber assembly having a relatively small amount. Of course, even if the same long-fiber web as mentioned above is used alone or in combination using a recycled polystyrene resin, it can be used as a vacuum heat insulating material. Moreover, in order to further increase the temperature of the vacuum heat insulating material of polystyrene long fibers, it is also possible to use a long fiber (for example, polycarbonate, polysulfone, etc.) having a slightly high deformation temperature in combination with the skin layer portion or the like. .

  In the process of spinning and fiberizing the molten resin, the state of the fiber surface can be changed by the following operation. Specifically, the stretchability of the resin can be changed by changing the amount of resin discharged, the amount of hot air blown when spinning, the distance between the spinning nozzle and the fiber recovery conveyor, and the hardness of the fiber laminate Can be controlled. When the amount of resin discharged is large, the temperature of the resin increases when it is drawn and spun, so it tends to fuse with adjacent fibers, the fiber diameter increases, and the surface of the finished fiber laminate becomes It becomes hard. Further, if the amount of hot air blown at the time of spinning is reduced, the stretchability of the resin is reduced and the fiber diameter is increased because the resin is easily stretched, so that the surface of the finished fiber laminate is hardened. In addition, by shortening the distance between the spinning nozzle and the fiber collection conveyor, the time from spinning to collection is shortened, so the heat generation of the fiber itself cannot be eliminated, and fusion with adjacent fibers occurs and the fiber diameter increases. And the surface of the finished fiber laminate becomes hard. If the operations are reversed, the surface of the fiber laminate becomes soft, and various fiber laminates can be produced by combining the respective states.

  The jacket material has a material structure that covers the core material provided with an airtight portion therein, and a material that reflects the shape of the core material by vacuum sealing is preferable. For example, if a material with high rigidity is used as the jacket material, it becomes difficult to bend, and this may cause a pinhole after bending. Therefore, as the jacket material, a laminate film having a bag shape is used. The outermost layer corresponding to impact, the intermediate layer ensuring gas barrier properties, and the innermost layer that can be sealed by heat fusion are preferable. The outermost layer uses a polyamide film to improve puncture resistance, and an intermediate layer is provided with an ethylene-vinyl alcohol copolymer film having an aluminum vapor deposition layer. The innermost layer is a high density polyethylene, a linear low density polyethylene, a high A density polypropylene is mentioned, A high density polyethylene is preferable from a sealing performance and chemical attack property.

  For example, a plastic laminate film composed of polyethylene terephthalate as the outermost layer, aluminum foil as the intermediate layer, high-density polyethylene as the innermost layer, polyethylene terephthalate as the outermost layer, and ethylene-vinyl alcohol having an aluminum vapor deposition layer as the intermediate layer. Polymer, plastic laminate film made of high-density polyethylene in the innermost layer, and the like. In addition, although this embodiment demonstrates the example which covered the core material with the jacket material and vacuum-depressurized, after covering a core material with the inner packaging material, you may cover with an outer jacket material (outer packaging material), and may carry out vacuum pressure reduction. . And when covering a core material with an inner packaging material, in this embodiment, it pays attention to the friction coefficient of this inner packaging material and a core material (in the following description regarding this embodiment, the innermost layer of an outer jacket material) And the friction coefficient of the core material that touches it).

  Adsorbent is used to improve the reliability of vacuum insulation. The adsorbent is not limited as long as it absorbs gas such as carbon dioxide, oxygen, nitrogen, and water vapor, and adsorbent of dosonite, hydrotalcite, metal hydroxide, molecular sieves, silica gel, calcium oxide, zeolite, hydrophobic Use absorbents of water-soluble zeolite, activated carbon, potassium hydroxide and lithium hydroxide. At that time, pinholes are likely to be generated in the jacket material by piercing with the adsorbent protrusions. Therefore, pinhole generation in the jacket material is preferably suppressed by sandwiching it with polystyrene long fibers.

  The vacuum heat insulating material mentioned above can be used for the refrigerator etc. which have a heat insulation box. A refrigerator or the like has a space formed by an outer box and an inner box and is filled with a foamed resin foam, and a vacuum heat insulating material can be inserted into the space filled with the foamed resin foam. The method for inserting the vacuum heat insulating material and the foamed resin is a method in which the vacuum heat insulating material is previously installed in the space formed by the inner box and the outer box, and then the foamed resin foam is injected and integrally molded, or the vacuum heat insulating material There is a method in which a vacuum heat insulating material in which a foamed resin foam is integrally molded in advance is produced and the vacuum heat insulating material is attached to an inner box or an outer box or sandwiched between both. These methods are appropriately used depending on an article that requires heat insulation performance.

  The above vacuum heat insulating material can be applied to each product that needs to be kept warm. Examples include refrigerators, vehicles, building materials, automobiles, medical equipment, and the like. In particular, it is effective for all products that include a heat exchange section and require heat insulation. By applying the vacuum heat insulating material of the present embodiment to the refrigerator, the heat insulation / cooling function can be improved, and a reduction in heat leakage and energy saving can be expected. Refrigerators and the like include vending machines, product display shelves, refrigerators, cooler boxes and the like in addition to refrigerators and freezers for home use and commercial use. Moreover, by applying it to a vehicle, the space inside the vehicle can be expanded by installing a space-saving vacuum heat insulating material, and a sufficient heat insulating effect can be provided to expect problems such as condensation.

  Next, the structure and production of a vacuum heat insulating material according to an embodiment of the present invention and a refrigerator in which the vacuum heat insulating material is inserted will be described with reference to the drawings.

  In the drawings, 1 is a vacuum heat insulating material, 2 is a jacket material, 3 is a core material of resin fiber, 3a is a first core material layer, 3b is a second core material layer, 4 is an adsorbent, 5 is glass wool or polyester fiber , 6 is a conventional vacuum heat insulating material, 7 is a heat insulating box, 8 is a rigid polyurethane foam, 9 is a box, 10 is a refrigerator, 11 is a refrigerator inner box, 12 is a refrigerator outer box, 13 is a jig, and 14 is a bending tool. , 15 represents the outermost layer of the bent portion of the vacuum heat insulating material.

  In FIG. 1, the cross-sectional schematic diagram of the vacuum heat insulating material 1 of this embodiment is shown. The vacuum heat insulating material 1 has a configuration in which a core material 3 of polystyrene long fibers is sealed under reduced pressure with an outer covering material 2 together with an adsorbent 4. According to this vacuum heat insulating material 1, a flat vacuum heat insulating material having a low thermal conductivity that can achieve both heat insulating performance and environmental load can be obtained by using the resin fiber core material 3. The core material 3 is composed of a plurality of laminated bodies, and the core material 3a and the core material 3b are composed of resin fibers having different friction coefficients and having a difference of 0.1 or more and less than 1.0. As a result, it is possible to provide an excellent vacuum heat insulating material that can be used for a box and a refrigerator by combining a vacuum heat insulating material having a planar shape or a bent shape.

  On the other hand, the cross-sectional schematic diagram of the conventional vacuum heat insulating material 6 is shown in FIG. It is a vacuum heat insulating material configured to seal the glass wool core material 5 together with the adsorbent 4 with the jacket material 2 under reduced pressure. Although the conventional vacuum heat insulating material 6 has good heat insulating properties with glass wool, the environmental load is inferior, and a core material that achieves both heat insulating performance and environmental load cannot be obtained. In addition, pinholes that occur due to thickness reduction or thinning of the outer portion of the jacket material 2 are likely to occur at the cut and bent portions of the fibers, and the heat insulation performance to the vacuum heat insulating material is degraded.

  The perspective schematic diagram of the heat insulation box 7 provided with the vacuum heat insulating material 1 which concerns on FIG. 3 at this embodiment is shown. This heat insulation box 7 has a structure in which the vacuum heat insulating material 1 containing resin fibers is inserted into a part of the inner surface side of a box 9 obtained by press-molding an iron plate, and the rigid polyurethane foam 8 is foam-filled in the gap portion. belongs to. When producing the vacuum heat insulating material, a bent heat insulating material obtained by bending a part of the core material 3 of the deformed portion is used.

  The vacuum heat insulating material which concerns on this embodiment was produced by changing the friction coefficient of the resin fiber used for the core material, and confirmed the bending rate and the deterioration rate of thermal conductivity. The results are shown in FIG. The conventional example, comparative examples 1 and 2 and examples 1 to 5 shown in FIG. 6 exemplify the configuration of the core material and the coefficient of friction, as described in detail below. This is a comparison of the thickness reduction rate of the material, the distortion of the outermost layer of the jacket material, the degree of deterioration in thermal conductivity, and the like.

  To confirm the bendability, a bending test as shown in FIG. As shown in FIG. 5, the vacuum heat insulating material 1 is placed on a jig 13, and bending is performed with a bending tool 14. At this time, the strain in the outermost layer 15 in the bent portion was measured with a strain gauge, and at the same time, the increase or decrease in the thickness before and after the bending was measured.

  The bending test conditions were a crosshead speed of 4.5 mm / min, a bending span of 100 mm, the jig 13 and the tip of the bending tool 14 were 10 mm, and the shape of the bending test piece was 150 × 100 × 10 mm. The result of the bending test is shown in FIG. In FIG. 6, in the conventional example, the comparative example, and the example, the friction coefficient between the jacket material and the laminated body in contact with the jacket material is constant.

According to the bending test result shown in FIG. 6, it can be seen that the problem in the bending test of the vacuum heat insulating material is a reduction in the distortion and thickness of the composite resin film in the outermost layer. Here, when distortion occurs in the jacket material 2, a problem that the degree of vacuum leaks occurs, and when the reduction rate of the wall thickness is large, a problem that heat easily leaks occurs.

  In the vacuum heat insulating material having the above-described configuration, the gist of the embodiment of the present invention is to reduce the friction coefficient μ2 between the jacket material in the vacuum heat insulating material that can be bent and the fiber laminate in contact with the outer cover material. In addition to improving the slidability between the core materials, the core material is more strongly bonded (stacking materials having different friction coefficients) (coefficient of friction between core materials μ1) between the jacket material and the core material. By making it larger than the friction coefficient (μ1> μ2), it is to relatively improve the slip between the jacket material and the core material. That is, by making μ1> μ2, the friction coefficient between the core materials is increased so as not to slip, and the core material and the jacket material are relatively slid.

  In addition, as a method of reducing the coefficient of friction between the jacket material and the laminated body in contact with it, it is performed by manipulating the surface state at the time of producing the core material. Specifically, the step of spinning the resin into fibers The amount of resin discharged, the amount of hot air blown during spinning, and the distance between the spinning nozzle and the fiber recovery conveyor can be changed to change the stretchability of the resin and control the hardness of the fiber laminate. it can. In this way, the state of the core surface can be manipulated.

  Next, a plurality of examples of the vacuum heat insulating material according to the present embodiment will be specifically described below in comparison with conventional examples and comparative examples.

"Conventional example"
First, the conventional example will be described. A core material laminated with glass wool that does not contain a binder was placed in an outer cover material made of a gas barrier film, sandwiched with an adsorbent for gas adsorption (molecular sieves 13X), and vacuum sealed with a vacuum packaging machine. The friction coefficient of the glass wool core material used at this time is the same because all the layers are made of the same material (the friction coefficient difference is 0, see FIG. 2). When the bending test shown in FIG. 5 was performed using the obtained vacuum heat insulating material, the reduction rate of the thickness of the core material was 35.9%, and the distortion of the outermost layer of the jacket material was 17.1%.

  Further, the thermal conductivity of the vacuum heat insulating material was measured at 10 ° C. using an AUTO-Λ manufactured by Eihiro Seiki Co., Ltd. The measurement was performed before and after the bending of the vacuum heat insulating material, and the measurement after the bending was the result of measurement after leaving the vacuum heat insulating material in a constant temperature bath at 70 ° C. for 30 days to accelerate deterioration. The degree of deterioration of the thermal conductivity before and after the bending process was 68%.

  From the above measurement results, it was found that when the conventional vacuum heat insulating material was subjected to bending, there was an obstacle to the deterioration over time of the heat insulating performance (thermal conductivity) of the vacuum heat insulating material.

"Example 1"
The flat plate-shaped vacuum heat insulating material of Example 1 was manufactured as follows. A general-purpose polystyrene resin was used, and while a polystyrene was passed through a plurality of nozzle tips by spunbond spinning, fibers were collected on a collector from an ejector controlled by air injection to form a substantially circular long fiber web. At this time, spinning was carried out under two different conditions, and the surface state was changed, so that the friction coefficient difference between the polystyrene resin fibers forming the first layer and the second layer of the core material was 0.2. The core material produced in this manner was placed in an outer cover material made of a gas barrier film, sandwiched with an adsorbent (molecular sieves 13X) for gas adsorption, and vacuum sealed with a vacuum packaging machine. When the bending test shown in FIG. 5 was performed using the obtained vacuum heat insulating material, the thickness reduction rate of the core material was 22.9%, and the strain of the outermost layer of the outer cover material was 15.4%.

  Further, the thermal conductivity of the vacuum heat insulating material was measured at 10 ° C. using an AUTO-Λ manufactured by Eihiro Seiki Co., Ltd. The measurement was performed before and after the bending of the vacuum heat insulating material, and the measurement after the bending was the result of measurement after leaving the vacuum heat insulating material in a constant temperature bath at 70 ° C. for 30 days to accelerate deterioration. The degree of deterioration of the thermal conductivity before and after the bending process was 51%.

  From this, by increasing the coefficient of friction of each layer forming the core material, when the vacuum heat insulating material is bent, the sliding property of the core material to the outer cover material is improved, and Stress concentration was reduced and the outermost layer of the jacket material was less strained. (Stress between the innermost layer of the jacket material and the core material in contact with it was created by creating the difficulty of slipping between the overlapping core materials. Concentration can be avoided, the frictional force at this part can be reduced, slipperiness can be generated, and distortion of the jacket material can be reduced). As a result, it is possible to reduce the deterioration of the heat insulating performance after bending the vacuum heat insulating material.

"Example 2"
The flat plate-shaped vacuum heat insulating material of Example 2 was manufactured as follows. A general-purpose polystyrene resin was used, and resin fibers fibrillated by hot air injection were collected on a collector while polystyrene was passed through a plurality of nozzle tips by melt blow spinning to form a fiber laminate. At this time, spinning was performed under two different conditions, and the surface state was changed, so that the friction coefficient difference between the polystyrene resin fibers forming the first layer and the second layer of the core material was 0.6. The core material produced in this manner was placed in an outer cover material made of a gas barrier film, sandwiched with an adsorbent (molecular sieves 13X) for gas adsorption, and vacuum sealed with a vacuum packaging machine. When the bending test shown in FIG. 5 was performed using the obtained vacuum heat insulating material, the reduction rate of the thickness of the core material was 20.7%, and the distortion of the outermost layer of the jacket material was 13.8%.

  Further, the thermal conductivity of the vacuum heat insulating material was measured at 10 ° C. using an AUTO-Λ manufactured by Eihiro Seiki Co., Ltd. The measurement was performed before and after the bending of the vacuum heat insulating material, and the measurement after the bending was the result of measurement after leaving the vacuum heat insulating material in a constant temperature bath at 70 ° C. for 30 days to accelerate deterioration. The degree of deterioration of the thermal conductivity before and after the bending process was 43%.

  From this, by increasing the coefficient of friction of each layer forming the core material, when the vacuum heat insulating material is bent, the sliding property of the core material to the outer cover material is improved, and Stress concentration was reduced and the outermost layer of the jacket material was less strained. (Stress between the innermost layer of the jacket material and the core material in contact with it was created by creating the difficulty of slipping between the overlapping core materials. Concentration can be avoided, the frictional force at this part can be reduced, slipperiness can be generated, and distortion of the jacket material can be reduced). As a result, it is possible to reduce the deterioration of the heat insulating performance after bending the vacuum heat insulating material.

"Example 3"
The flat plate-shaped vacuum heat insulating material of this Example 3 was produced as follows. Using general-purpose polystyrene resin and polypropylene resin, resin fibers fibrillated by hot air injection were collected on a collector while passing polystyrene and polypropylene through the tip of a plurality of nozzles by melt blow spinning to form fiber laminates. At this time, the friction coefficient difference between the first core material layer made of polypropylene and the second core material layer made of polystyrene was 0.4. The core material produced in this manner was placed in an outer cover material made of a gas barrier film, sandwiched with an adsorbent (molecular sieves 13X) for gas adsorption, and vacuum sealed with a vacuum packaging machine. When the bending test shown in FIG. 5 was performed using the obtained vacuum heat insulating material, the thickness reduction rate of the core material was 21.8%, and the distortion of the outermost layer of the outer cover material was 14.7%.

  Further, the thermal conductivity of the vacuum heat insulating material was measured at 10 ° C. using an AUTO-Λ manufactured by Eihiro Seiki Co., Ltd. The measurement was performed before and after the bending of the vacuum heat insulating material, and the measurement after the bending was the result of measurement after leaving the vacuum heat insulating material in a constant temperature bath at 70 ° C. for 30 days to accelerate deterioration. The degree of deterioration of the thermal conductivity before and after the bending process was 46%.

  From this, by increasing the friction coefficient of each layer forming the core material, when the vacuum heat insulating material is bent, the slipping property of the core material with respect to the jacket material is improved in the same manner as in Examples 1 and 2. The stress concentration on the jacket material was alleviated, and the distortion of the outermost layer of the jacket material was alleviated. As a result, it is possible to reduce the deterioration of the heat insulating performance after bending the vacuum heat insulating material.

Example 4
The flat plate-shaped vacuum heat insulating material of the present Example 4 was produced as follows. A fiber laminate formed by melt blow spinning using a general-purpose polystyrene resin was used as the first core material layer, and the second core material layer was a glass wool laminate containing no binder. At this time, the friction coefficient difference between the first core material layer made of polystyrene and the second core material layer made of glass wool was 0.7. The core material produced in this manner was placed in an outer cover material made of a gas barrier film, sandwiched with an adsorbent (molecular sieves 13X) for gas adsorption, and vacuum sealed with a vacuum packaging machine. When the bending test shown in FIG. 5 was performed using the obtained vacuum heat insulating material, the thickness reduction rate of the core material was 23.6%, and the distortion of the outermost layer of the jacket material was 12.5%.

  Further, the thermal conductivity of the vacuum heat insulating material was measured at 10 ° C. using an AUTO-Λ manufactured by Eihiro Seiki Co., Ltd. The measurement was performed before and after the bending of the vacuum heat insulating material, and the measurement after the bending was the result of measurement after leaving the vacuum heat insulating material in a constant temperature bath at 70 ° C. for 30 days to accelerate deterioration. The degree of deterioration of the thermal conductivity before and after the bending process was 38%.

  From this, by increasing the coefficient of friction of each layer forming the core material, when the vacuum heat insulating material is bent, the slipping property of the core material with respect to the jacket material is improved in the same manner as in Examples 1-3. The stress concentration on the jacket material was alleviated, and the distortion of the outermost layer of the jacket material was alleviated. As a result, it is possible to reduce the deterioration of the heat insulating performance after bending the vacuum heat insulating material.

"Example 5"
The flat plate-shaped vacuum heat insulating material of Example 5 was produced as follows. Using general-purpose polystyrene resin and polypropylene resin, resin fibers fibrillated by hot air injection were collected on a collector while passing polystyrene and polypropylene through the tip of a plurality of nozzles by melt blow spinning to form fiber laminates. At this time, the friction coefficient difference between the core material first layer made of polypropylene and the core material second layer made of polystyrene is 0.4, and the core material made of polypropylene made under a spinning condition different from that of the first layer is used. The friction coefficient difference between the three layers and the second core material layer was 0.6. The core material produced in this manner was placed in an outer cover material made of a gas barrier film, sandwiched with an adsorbent (molecular sieves 13X) for gas adsorption, and vacuum sealed with a vacuum packaging machine. When the bending test shown in FIG. 5 was performed using the obtained vacuum heat insulating material, the thickness reduction rate of the core material was 21.8%, and the strain of the outermost layer of the jacket material was 12.9%.

  Further, the thermal conductivity of the vacuum heat insulating material was measured at 10 ° C. using an AUTO-Λ manufactured by Eihiro Seiki Co., Ltd. The measurement was performed before and after the bending of the vacuum heat insulating material, and the measurement after the bending was the result of measurement after leaving the vacuum heat insulating material in a constant temperature bath at 70 ° C. for 30 days to accelerate deterioration. The degree of deterioration of the thermal conductivity before and after the bending process was 40%.

  From this, by increasing the coefficient of friction of each layer that forms the core material, when the vacuum heat insulating material is bent, the sliding property of the core material to the outer cover material is improved, and stress concentration on the outer cover material is improved. And the distortion of the outermost layer of the jacket material was alleviated. As a result, it is possible to reduce the deterioration of the heat insulating performance after bending the vacuum heat insulating material.

“Comparative Example 1”
The flat-plate-shaped vacuum heat insulating material of the comparative example 1 which should be contrasted with the present Examples 1-5 was produced as follows. A general-purpose polystyrene resin was used, and resin fibers fibrillated by hot air injection were collected on a collector while polystyrene was passed through a plurality of nozzle tips by melt blow spinning to form a fiber laminate. At this time, spinning was performed under two different conditions, and the surface state was changed, so that the difference in friction coefficient between the polystyrene resin fibers forming the core first layer and the second layer was 0.05. The core material produced in this manner was placed in an outer cover material made of a gas barrier film, sandwiched with an adsorbent (molecular sieves 13X) for gas adsorption, and vacuum sealed with a vacuum packaging machine. When the bending test shown in FIG. 5 was performed using the obtained vacuum heat insulating material, the thickness reduction rate of the core material was 26.7%, and the distortion of the outermost layer of the jacket material was 17.3%.

  Further, the thermal conductivity of the vacuum heat insulating material was measured at 10 ° C. using an AUTO-Λ manufactured by Eihiro Seiki Co., Ltd. The measurement was performed before and after the bending of the vacuum heat insulating material, and the measurement after the bending was the result of measurement after leaving the vacuum heat insulating material in a constant temperature bath at 70 ° C. for 30 days to accelerate deterioration. The degree of deterioration of the thermal conductivity before and after the bending process was 70%.

  From the above, under the condition where the difference in friction coefficient is small, the degree of deterioration of the bending process and the thermal conductivity when using the conventional glass wool as the core material was not significantly different.

"Comparative Example 2"
The flat plate-shaped vacuum heat insulating material of the comparative example 2 was produced as follows. A general-purpose polystyrene resin was used, and resin fibers fibrillated by hot air injection were collected on a collector while polystyrene was passed through a plurality of nozzle tips by melt blow spinning to form a fiber laminate. At this time, spinning was performed under two different conditions, and the surface state was changed, whereby the difference in friction coefficient between the polystyrene resin fibers forming the core first layer and the second layer was 1.0. The core material produced in this manner was placed in an outer cover material made of a gas barrier film, sandwiched with an adsorbent (molecular sieves 13X) for gas adsorption, and vacuum sealed with a vacuum packaging machine. When the bending test shown in FIG. 5 was performed using the obtained vacuum heat insulating material, the thickness reduction rate of the core material was 21.5%, and the distortion of the outermost layer of the jacket material was 16.3%.

  Further, the thermal conductivity of the vacuum heat insulating material was measured at 10 ° C. using an AUTO-Λ manufactured by Eihiro Seiki Co., Ltd. The measurement was performed before and after the bending of the vacuum heat insulating material, and the measurement after the bending was the result of measurement after leaving the vacuum heat insulating material in a constant temperature bath at 70 ° C. for 30 days to accelerate deterioration. The degree of deterioration of the thermal conductivity before and after the bending process was 61%.

  As described above, on the condition that the friction coefficient difference in Comparative Example 2 is large (larger than the friction coefficient difference in Examples 1 to 5 shown in FIG. 6), the core materials are firmly adhered to each other and moderately flexible. Therefore, when bending is performed, it is considered that a stress concentration part occurred in a part of the overlap between the core materials, the deterioration of the core material and the jacket material becomes large, and the conventional glass wool is used as the core material. The bending distortion and the degree of deterioration of thermal conductivity were not much different.

  What can be said here is that it is more advantageous for bending work by laminating the core materials with different friction coefficients, and providing a difference in the friction coefficients (outer coating material outermost layer distortion, thermal conductivity degradation). From a numerical value such as degree), if the friction coefficient difference is too large (see Comparative Example 2), it can be said that it deteriorates on the contrary for the reason described above.

"Example 6"
Example 6 of this embodiment is an application example in which the vacuum heat insulating material according to this embodiment is used in a refrigerator, as shown in FIG. The refrigerator is insulated by a vacuum heat insulating material and other heat insulating materials. In the refrigerator, the temperature difference from the outside air temperature is particularly large between the peripheral portion of the compressor and the outside surface of the inner box on the back of the refrigerator. It is effective to use the vacuum heat insulating material 1 of this embodiment for this part.

  The vacuum heat insulating material 1 was provided with a core material of polystyrene long fiber, and a combination of a deformed portion and a flat portion was used. The vacuum heat insulating materials 1A and 1B are vacuum heat insulating materials disposed along the bent portion of the heat insulating wall. When the vacuum heat insulating material is installed on the inner box side of the bent portion (1A), it is installed so as to be in close contact with the inner box 11 along the shape of the inner box 11. Moreover, when installing a vacuum heat insulating material in the outer box side of a bending part (1B), it has installed along the shape of the outer box 12. FIG. The bent part of the heat insulating wall is a part constituting the deformed part of the heat insulating wall. In addition, the vacuum heat insulating materials 1C and 1D are also arranged on the back surface of the outer box 21 and one of the refrigerator doors.

  A box and a polyol and isocyanate were injected and filled using a high-pressure foaming machine to prepare a heat insulating material for the refrigerator. Rigid polyurethane foam foam insulation is 40 parts by weight of polyether polyol obtained by adding propylene oxide to m-tolylenediamine having an average hydroxyl value of 450 as propylene, and propylene in ortho-tolylenediamine having an average hydroxyl value of 470. 30 parts by weight of polyether polyol with oxide added, 30 parts by weight of polyether polyol with propylene oxide added to o-tolylenediamine having an average hydroxyl value of 380, and 100 parts by weight of mixed polyol component, 15 parts by weight of cyclopentane 1.5 parts of water, 1.2 parts of tetramethylhexamethylenediamine as a reaction catalyst and 2 parts of trimethylaminoethylpiperazine, 2 parts by weight of organosilicone compound X-20-1614 as a foam stabilizer, Millionate M as an isocyanate component And foam filling with diphenylmethane diisocyanate syncytial 125 parts.

  The heat leakage amount and power consumption of the refrigerator after heat insulation were measured. The amount of heat leakage of the refrigerator was measured as the amount of heat leakage from the interior by setting the temperature condition opposite to the operation state of the refrigerator. Specifically, a temperature condition in which a refrigerator is installed in a thermostatic chamber of −10 ° C. and the heater temperature is set to a predetermined measurement condition (temperature difference) to compare the power consumption and cooling performance of the refrigerator. Measured with The power consumption of the refrigerator was performed according to JIS measurement standards.

  As a result, it was possible to provide a refrigerator capable of reducing 7.5% in terms of heat leakage and 10% in terms of power consumption, compared to a refrigerator in which no vacuum heat insulating material was inserted. In addition, the said rigid polyurethane foam can be used for a refrigerator and a heat insulation box with the heat insulating material 1 of this embodiment, A phenol foam, a styrene foam, etc. are illustrated in addition to a rigid polyurethane foam, Cyclopentane Rigid polyurethane foam using water and water as a mixed foaming agent is preferred.

"Example 7"
Example 7 of the present embodiment is an application example in which the vacuum heat insulating material is used as a heat insulating material for a vehicle having a double skin structure material. In a vehicle having a double skin structure, the side surface and the roof structure have a curved surface in order to reduce the weight and improve the pressure resistance, and it is difficult to attach the conventional vacuum heat insulating material. Moreover, when it affixes, a distortion | strain will arise in a jacket material, an internal vacuum degree will fall and heat insulation performance will be inferior.

  The vacuum heat insulating material has a core material of a polystyrene long-fiber web, and was prepared by combining a flat plate shape and a bent shape. When the vacuum heat insulating material of the present embodiment is used, it can be attached along the curved surface of the structure, has a heat insulating effect on the vehicle, and does not cause problems such as condensation in the vehicle. In addition, it is a vacuum heat insulating material with excellent heat insulating properties, and the effect of widening the interior space of the vehicle by reducing the thickness of the heat insulating material is also seen, and the vacuum heat insulating material of this embodiment is also effective as a heat insulating material for vehicles. is there.

"Example 8"
Example 8 of this embodiment is an application example in which a vacuum heat insulating material is used as a heat insulating material for a vending machine. In vending machines, in order to save energy and improve the space volume, it has a structure with a flat plate vacuum heat insulating material on its side and a bent shape vacuum heat insulating material on the bottom surface. When bent, the jacket material is distorted, the internal vacuum is lowered, and the heat insulation performance is deteriorated.

  Therefore, in Example 8, the vacuum heat insulating material 1 has a core material using a polystyrene long fiber web, and is manufactured by combining a flat plate shape and a bent shape. By using the vacuum heat insulating material 1, it can be pasted along the curved surface of the structure, and the box is filled with rigid polyurethane foam in the same manner as the refrigerator. The vacuum insulation material is flat and bent in shape and has excellent heat insulation properties without lowering the degree of vacuum inside. Therefore, the vacuum insulation material of the present invention can be used as a heat insulation material for vending machines. It is valid.

  As described above, the vacuum heat insulating material according to the embodiment of the present invention fiberizes the surface of each laminate constituting the core material of the vacuum heat insulating material into different states, and the friction coefficient between the core materials is the core material. When the vacuum heat insulating material is bent, the outer cover material is improved by making the friction coefficient of the core material and the outer cover material or the core material and the inner packaging material larger. This can be achieved by relaxing the stress concentration at one point of the core material. Moreover, it leads also to the shift | offset | difference suppression of a core material. In that case, as a method of making the surface of a laminated body into a different state, it can operate by the manufacturing method in the case of fiberization. For example, a resin fiber produced by spinning a resin material such as a plastic material can be given. The resin fibers can be made by using the spunbond method (a method in which a thermoplastic polymer is melted and ejected into a continuous long fiber) or the melt blow method (formed by applying high-temperature air to make the fibers finer) The resin used can be widely used from a general-purpose resin such as polystyrene and polypropylene to a super engineering plastic resin such as polyimide. Further, a recycled resin may be used regardless of the virgin resin.

  As described above, in this embodiment, by increasing the coefficient of friction between the laminates forming the core material of the vacuum heat insulating material, when the vacuum heat insulating material is bent, the slipping property of the core material with respect to the jacket material is improved. By relieving the stress concentration at one point of the jacket material and the core material in the bent part, the three-dimensional bending of the vacuum heat insulating material is realized. Furthermore, since the resin used for fiberization can be used not only for virgin products but also for recycled products, cost reduction and environmental load reduction can be achieved.

DESCRIPTION OF SYMBOLS 1 Vacuum heat insulating material 2 Cover material 3 Resin fiber core material 3a Core material 1st layer 3b Core material 2nd layer 4 Adsorbent 5 Glass wool or polyester fiber 6 Conventional vacuum heat insulating material 7 Heat insulation box 8 Hard polyurethane foam 9 Box DESCRIPTION OF SYMBOLS 10 Refrigerator 11 Refrigerator inner box 12 Refrigerator outer box 13 Jig 14 Bending tool 15 Outermost layer of vacuum insulation material bending part

Claims (6)

A vacuum heat insulating material comprising a core material composed of a plurality of laminates having fibers of a long fiber web, and a jacket material having gas barrier properties,
The core material is a multi-layered body having fibers including at least resin fibers having different friction coefficients in each layered body,
By manipulating the surface state of the resin fiber, the friction coefficient between the core material and the innermost layer of the jacket material in contact with the core material is formed smaller than the friction coefficient between the core materials having different friction coefficients, The vacuum heat insulating material characterized by relieving the stress in the bending site | part at the time of bending the said vacuum heat insulating material. In claim 1,
A vacuum heat insulating material characterized in that the core material having a different friction coefficient in each laminated body is a plurality of laminated bodies formed by melt spinning using a melt blow method or a spun bond method using a resin. In claim 1 or 2,
The vacuum heat insulating material characterized in that a difference in friction coefficient between laminates having different friction coefficients is 0.1 or more and less than 1.0.   A heat insulating box comprising the vacuum heat insulating material according to any one of claims 1 to 3 installed in a space formed by an outer box and an inner box together with a filled foam heat insulating material.   A refrigerator characterized in that the vacuum heat insulating material according to any one of claims 1 to 3 is installed in a space formed by an outer box and an inner box together with a filled heat insulating material. In claim 5,
A refrigerator, wherein the refrigerator is installed at a corner of the outer box or the inner box by bending the vacuum heat insulating material.