JP2018040421A - Core material for vacuum heat insulation panel, vacuum heat insulation panel and refrigerator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vacuum heat insulation panel that, even when a nonwoven fabric is constituted of resin fiber, can secure strength of the resin fiber and avoid a decline in heat insulation property, and to provide a vacuum heat insulation panel and a refrigerator.SOLUTION: There is provided a core material for a vacuum heat insulation panel where a plurality of nonwoven fabrics are laminated. The nonwoven fabric is constituted of a thermosetting resin fiber formed of a thermosetting resin.SELECTED DRAWING: Figure 1

Description

  The present embodiment relates to a core material of a vacuum heat insulation panel, a vacuum heat insulation panel, and a refrigerator.

  Vacuum insulation panels used for various devices and facilities are required to have high thermal insulation properties and further reduction in thickness and weight. The core material of the conventional vacuum heat insulation panel is mainly formed of glass fiber. However, the glass fibers used as these core materials have a large specific gravity, and there is a problem that it is difficult to reduce the thickness and weight of the vacuum heat insulating panel.

Japanese Patent No. 4713566

  In order to solve the above-described problems, in recent years, it has been considered that the core material of the vacuum heat insulation panel is made of resin fibers. However, resin fibers tend to be weaker than glass fibers. For this reason, when the inside of the vacuum heat insulation panel is in a reduced pressure state such as 2 Pa or less, the nonwoven fabric made of resin fibers is compressed due to insufficient strength, the porosity inside the vacuum heat insulation panel decreases, and the contact area between the resin fibers increases. As a result, the number of heat transfer paths increases, resulting in a decrease in heat insulation performance. Therefore, when a nonwoven fabric is comprised with a resin fiber, the technique which solves the strength subject is calculated | required.

  Therefore, in the present embodiment, even when the nonwoven fabric is constituted by resin fibers, the core material of the vacuum heat insulation panel that can ensure the strength of the resin fibers and can avoid deterioration of the heat insulation performance, vacuum It aims at providing a heat insulation panel and a refrigerator.

  The core material of the vacuum heat insulation panel of this embodiment has a configuration in which a plurality of nonwoven fabrics are laminated. And the nonwoven fabric is comprised with the thermosetting resin fiber which consists of thermosetting resin.

The schematic diagram which shows the core material and nonwoven fabric of the vacuum heat insulation panel by embodiment Typical sectional drawing which shows the vacuum heat insulation panel by embodiment The exploded perspective view which illustrates typically the example of composition of the core material of the vacuum heat insulation panel by an embodiment The side view which illustrates typically the example of composition of the core material of the vacuum thermal insulation panel by an embodiment The schematic diagram which shows the side view of the core material of the vacuum heat insulation panel by embodiment The schematic diagram which shows the manufacturing apparatus of the core material of the vacuum heat insulation panel by embodiment Schematic showing the physical properties of the solvent The figure which contrasted the physical property of the Example by embodiment and a comparative example The typical perspective view showing the heat insulation box of the refrigerator by an embodiment The typical perspective view which shows the vacuum heat insulation panel group of the refrigerator by embodiment Sectional drawing which illustrates the state of the vacuum heat insulation panel before pressure reduction and after pressure reduction

Hereinafter, one embodiment concerning a core material of a vacuum heat insulation panel, a vacuum heat insulation panel, and a refrigerator is described based on a drawing.
As shown in FIG. 1, the core material 10 has a nonwoven fabric 11 laminated in a plurality of layers. The nonwoven fabric 11 is formed of resin fibers 12 that are randomly intertwined. The resin fiber 12 is formed by an electrospinning method. The resin fiber 12 formed by the electrospinning method is a long fiber having an outer diameter d of d <1 μm and a length of 1000 times or more of the outer diameter. Further, the resin fiber 12 is not linear as a whole, but is a curved shape that is randomly curved. Therefore, the resin fibers 12 are easily entangled with each other, and a plurality of layers are easily formed. By utilizing the electrospinning method, the spinning of the resin fibers 12 and the formation of the nonwoven fabric 11 can be performed simultaneously. As a result, the core material 10 can be easily formed with a short man-hour.

  Moreover, the resin fiber 12 which comprises the nonwoven fabric 11 can ensure an ultra-thin outer diameter of nanometer to micrometer easily by utilizing the electrospinning method. Therefore, the nonwoven fabric 11 has a very thin thickness per sheet, and the core material 10 also has a small thickness. In the case of a conventional glass fiber, the fiber length is short and the fibers are less entangled. Therefore, when glass fiber is used, it becomes difficult to maintain the shape of the nonwoven fabric. In the case of glass fiber, it is generally difficult to simultaneously spin glass fiber and form a nonwoven fabric. When using the conventional glass fiber, the nonwoven fabric is formed in the manner of a paper basket with the glass fiber dispersed in water. If the spinning of the glass fiber and the formation of the nonwoven fabric are performed simultaneously, a cotton-like nonwoven fabric having a large thickness is formed, and it is difficult to form a thin nonwoven fabric having a small thickness.

  Thus, in the case of this embodiment, the core material 10 is formed with the nonwoven fabric 11 which consists of the laminated | stacked several layer. As for the core material 10, the nonwoven fabric 11 of several hundred layers to several thousand layers or more is laminated | stacked, for example. The resin fibers 12 forming the nonwoven fabric 11 of the present embodiment are formed in a circular or elliptical shape with a substantially uniform cross section.

  The resin fibers 12 forming the nonwoven fabric 11 are formed of an organic polymer having a density, that is, a specific gravity smaller than that of glass. By forming the resin fiber 12 with a polymer having a density lower than that of glass, the resin fiber 12 can be reduced in weight. The nonwoven fabric 11 may be a mixture of two or more types of resin fibers 12. As an example of the nonwoven fabric 11 formed by blending, polystyrene fiber and aromatic polyamide resin (registered trademark: Kepler) are used. In addition to the above, the non-woven fabric 11 includes polycarbonate, polymethyl methacrylate, polypropylene, polyethylene, polyethylene terephthalate, polybutylene terephthalate, polyamide, polyoxymethylene, polyamideimide, polyimide, polysulfane, polyethersulfane, poly Formed with one kind of resin fiber 12 selected from ether imide, polyether ether ketone, polyphenylene sulfide, modified polyphenylene ether, syndiotactic polystyrene, liquid crystal polymer, urea resin, unsaturated polyester, polyphenol, melamine resin, epoxy resin, etc. Alternatively, it may be formed by blending two or more types of resin fibers 12.

  In this case, the resin fibers 12 to be blended are all set so that the outer diameter d is d <1 μm. As described above, by blending a plurality of types of resin fibers 12, it is possible to improve the heat insulation, weight reduction, and strength of the nonwoven fabric 11. On the contrary, when the volume of voids formed between the intertwined resin fibers 12 is reduced in the nonwoven fabric 11, the number of the voids is increased. As the number of voids between the resin fibers 12 increases, the heat insulation is improved. Therefore, it is preferable that the nonwoven fabric 11 has a fiber outer diameter d of the resin fiber 12 constituting the same is reduced to a nanometer order of d <1 μm. By reducing the outer diameter d of the resin fibers 12 in this way, the number of voids formed between the resin fibers 12 is reduced and the number is increased. By reducing the diameter in this way, the volume of voids formed between the intertwined resin fibers 12 becomes smaller and the number thereof increases, and the heat insulating property of the nonwoven fabric 11 is improved.

  Here, the above-described urea resin, unsaturated polyester, polyphenol, melamine resin, and epoxy resin are so-called thermosetting resin materials that are cured by application of heat. In this embodiment, it is particularly preferable to form the resin fiber 12 with an epoxy resin among these. When the resin fiber 12 is composed of a thermosetting resin fiber made of a thermosetting resin, the resin fiber 12 includes a main material made of a thermosetting resin material and a curing agent that hardens the main material. It is good to include. By adjusting the addition amount of the curing agent, the characteristics of the resin fiber 12 to be formed, for example, the hardness and rigidity of the fiber can be controlled.

  For example, various inorganic fillers such as silicon oxide, metal hydroxide, carbonate, sulfate, and silicate may be added to the resin fiber 12. Thus, by adding an inorganic filler to the resin fiber 12, the strength can be improved while maintaining the heat insulating property of the nonwoven fabric 11. Specifically, as the inorganic filler to be added, wollastonite, potassium titanate, zonotlite, gypsum fiber, aluminum porate, MOS (basic magnesium sulfate), aramid fiber, carbon fiber, glass fiber, talc, mica, glass flake Etc. can also be used.

  The core material 10 formed of the nonwoven fabric 11 is accommodated in a bag-shaped outer packaging material 13 as shown in FIG. The outer packaging material 13 is an airtight sheet in which gas permeability is eliminated by evaporating a metal or metal oxide or the like on, for example, one or more resin films. The outer packaging material 13 containing the core material 10 is sealed together with the core material 10 after reducing the inside to a pressure close to vacuum. Thereby, the outer packaging material 13 containing the core material 10 is formed as the vacuum heat insulation panel 14. In this case, the vacuum heat insulation panel 14 may accommodate a skeleton member serving as a skeleton inside the outer packaging material 13 in order to reduce crushing of the formed vacuum heat insulation panel 14.

  As shown in FIGS. 3 and 4, the core material 10 may include an aluminum foil 15 on one surface side laminated. The core material 10 formed of the nonwoven fabric 11 as described above is formed as the vacuum heat insulation panel 14 by reducing the pressure inside the outer packaging material 13 after being accommodated in the outer packaging material 13. Therefore, the vacuum heat insulating panel 14 may be crushed or deformed by the reduced pressure inside the outer packaging material 13. By providing the aluminum foil 15 on one surface side of the nonwoven fabric 11, the strength of the core material 10 is improved. Thereby, the crushing and deformation | transformation by pressure reduction can be reduced. Moreover, the core material 10 may be provided with the glass fiber layer 16 laminated | stacked with the nonwoven fabric 11, as shown in FIG. The glass fiber layer 16 has higher strength than the nonwoven fabric 11 formed of fine resin fibers 12. Therefore, by laminating the nonwoven fabric 11 and the glass fiber layer 16, although the thickness and weight are increased as compared with the case where the core material 10 is formed only by the nonwoven fabric 11, crushing and deformation due to reduced pressure can be reduced. The glass fiber layer 16 is not limited to the two layers shown in FIG. 5 and may be one layer or three or more layers.

Next, the manufacturing apparatus and manufacturing method for forming the nonwoven fabric 11 which comprises said core material 10 are demonstrated.
FIG. 6 is a schematic diagram illustrating an example of the manufacturing apparatus 20. The manufacturing apparatus 20 includes a transport unit 21, a nozzle unit 22, a counter electrode plate 23, a separation unit 24, and a winding unit 25. The conveyance unit 21 includes a pair of rollers 26 and rollers 27. A circulating belt 28 is provided between the roller 26 and the roller 27. At least one of the pair of rollers 26 or 27 is rotationally driven by a drive unit (not shown). Thereby, the belt 28 passed between the roller 26 and the roller 27 circulates by the rotation of the roller 26 or the roller 27.

  The nozzle part 22 is provided above the transport part 21. A plurality of nozzle portions 22 are arranged along the traveling direction of the belt 28. A plurality of nozzle portions 22 are also arranged in a direction perpendicular to the traveling direction of the belt 28, that is, in the depth direction of FIG. Thus, a plurality of nozzle portions 22 are arranged in a matrix above the transport portion 21. The counter electrode plate 23 is provided to face the nozzle portion 22. A belt 28 is sandwiched between the nozzle portion 22 and the counter electrode plate 23. A high voltage of several kV or more is applied between the nozzle portion 22 and the counter electrode plate 23. That is, an electric field is formed between the nozzle portion 22 and the counter electrode plate 23 by the applied high voltage.

  The separation unit 24 is provided on the downstream side in the traveling direction of the belt 28. The separation unit 24 separates the nonwoven fabric 11 formed on the nozzle unit 22 side of the belt 28 from the belt 28. The winding unit 25 is provided adjacent to the separation unit 24. The winding unit 25 winds the nonwoven fabric 11 separated from the belt 28 by the separating unit 24.

  The raw material resin to be the resin fibers 12 forming the nonwoven fabric 11 is supplied to the nozzle portion 22 in a state dissolved in a solvent. That is, the resin that is the raw material of the resin fiber 12 is supplied to the nozzle unit 22 as a solution. The resin solution supplied to the nozzle unit 22 is jetted from the nozzle unit 22 toward the belt 28 at a high pressure. At this time, an electric field by a high voltage is formed between the nozzle portion 22 and the counter electrode plate 23 as described above. The resin solution sprayed from the nozzle part 22 is refined by the application of a high voltage and is charged with electric charge. Therefore, the resin solution is randomly attracted from the nozzle part 22 to the counter electrode plate 23 by electrostatic action, including fluctuations. It is done. Further, when the resin solution sprayed at a high pressure is sprayed from the nozzle portion 22, the solvent is vaporized. Therefore, the solvent of the resin solution sprayed from the nozzle portion 22 is vaporized before reaching the counter electrode plate 23, and becomes a fine fiber and adheres to the belt 28 in a random shape. As a result, the nonwoven fabric 11 in which fine fibers are randomly entangled is formed on the surface of the belt 28 on the nozzle portion 22 side. At this time, the nonwoven fabric 11 will be in the state in which the resin fiber 12 injected from the several nozzle part 22 was entangled in several layers.

  At this time, the resin fibers 12 are ejected from the nozzle portion 22 in a random and random manner, that is, in an irregular state. For this reason, the resin fibers 12 are irregularly turned until they are sprayed from the nozzle portion 22 and reach the belt 28 on the counter electrode plate 23 side, and are formed in a random constricted shape that is not entirely straight. As a result, the resin fibers 12 that have reached the belt 28 on the counter electrode plate 23 side are entangled irregularly and firmly to form the nonwoven fabric 11. In addition, the resin fiber 12 may exhibit a spiral shape when ejected from the nozzle portion 22. The spiral-shaped resin fibers 12 are entangled more strongly with the other resin fibers 12 and contribute to improving the strength of the nonwoven fabric 11. Further, the resin fiber 12 is continuously ejected from the nozzle portion 22. Therefore, the resin fiber 12 to be formed is a single fiber that is substantially or completely continuous until the injection from the nozzle portion 22 is completed. As a result, the resin fiber 12 is a very long fiber having a fiber length of 1000 times or more with respect to the outer diameter of the fiber. Here, when the resin fiber 12 is composed of a thermosetting resin fiber, heat is applied to the nonwoven fabric 11, that is, the resin fiber 12 in the form of a sheet. Thereby, the thermosetting resin material which comprises the resin fiber 12 hardens | cures. Even if the thermosetting resin material is cured, the resin fibers 12 do not stick to each other.

  For comparison, for example, a glass fiber formed by using a conventional flame method has an outer diameter of 3 to 4 μm and a fiber length of about 200 μm. When the fiber length is short with respect to the outer diameter of the fiber, the short fibers are entangled with each other. Therefore, the formed nonwoven fabric is likely to be separated, and it is difficult to keep the shape stable. On the other hand, when the resin fiber 12 is formed by the electrospinning method as in the present embodiment, the fiber has a continuous and sufficient length without interruption. Therefore, the resin fiber 12 by the electrospinning method is not only entangled with other fibers but also continuously entangled with each other due to its length and an irregular shape due to rolling at the time of formation. As a result, the resin fiber 12 by the electrospinning method forms the nonwoven fabric 11 also by the strong entanglement of one fiber itself. Thereby, the resin fiber 12 of this embodiment can form the nonwoven fabric 11 of the more stable shape compared with the conventional glass fiber. Moreover, when the shape of the nonwoven fabric 11 is stabilized, when forming the core material 10, the advantage that lamination | stacking of the nonwoven fabric 11 is easy is also acquired.

  The formed nonwoven fabric 11 moves to the left in FIG. 6 along with the movement of the belt, and is separated from the belt 28 by the separation unit 24. The nonwoven fabric 11 is formed in a continuous sheet shape while a resin as a raw material is sprayed from the nozzle portion 22. Therefore, the nonwoven fabric 11 separated from the belt 28 is wound up in the form of a sheet at the winding portion 25. The wound nonwoven fabric 11 is cut into an appropriate size, and then, for example, 100 or more are laminated to form the core material 10.

  In addition, you may make it give the drying process for vaporizing and removing a solvent with respect to the nonwoven fabric 11 manufactured by the manufacturing apparatus 20. FIG. In this drying process, the manufactured nonwoven fabric 11 is placed in an environment of a predetermined temperature, for example, about 50 ° C. to 60 ° C., thereby removing the solvent remaining in the nonwoven fabric 11 as much as possible. Here, when the resin fiber 12 is composed of a thermosetting resin fiber, the drying temperature in this drying step can be set to 100 ° C. or more, for example. Therefore, even if water is used as the solvent, the solvent can be removed.

  In the case of the manufacturing apparatus 20 shown in FIG. 6, the outer diameter d and length of the resin fiber 12 forming the nonwoven fabric 11 are the concentration of the resin solution supplied to the nozzle part 22, the pressure of the jet, the nozzle part 22 and the counter electrode plate 23. And the voltage applied between the nozzle portion 22 and the counter electrode plate 23, the moving speed of the belt 28, and the like. The concentration of the resin solution to be supplied, the pressure of injection, the voltage to be applied, the distance between the nozzle portion 22 and the counter electrode plate 23, the moving speed of the belt 28, and the like depend on the desired outer diameter d and length of the resin fiber 12. Can be adjusted arbitrarily.

  As the solvent for dissolving the resin, for example, a solvent as shown in FIG. 7 is used. That is, a solvent having compatibility with the resin that is the material of the resin fiber 12 is used. The compatibility increases as the solubility parameter (SP) of the resin as the material approximates the SP of the solvent. In the electrospinning method, a highly compatible solvent is selected according to the resin used as the material of the resin fiber 12. For example, when polystyrene is selected as the material of the resin fiber 12, the SP of polystyrene is 9.1. At this time, the solvent is preferably selected from toluene having SP of 9.1. For example, when an epoxy resin that is a thermosetting resin material is selected as the material of the resin fiber 12, the solvent is preferably N, N-dimethylformamide exemplified in FIG.

  In addition, when the electrospinning method is used, the boiling point and dielectric constant of the solvent are also factors for selection. The resin is formed in a fiber shape after being sprayed from the nozzle portion 22 and before reaching the counter electrode plate 23. For this reason, the solvent is required to evaporate before reaching the counter electrode plate 23 without evaporating until the solution is ejected from the nozzle portion 22. For example, if the boiling point of the solvent is too low, it is ejected from the nozzle part 22 and evaporates before a high voltage is applied. Therefore, the resin fiber 12 is spun before it becomes sufficiently thin, and the resin fiber 12 having a desired outer diameter cannot be obtained. If the boiling point of the solvent is too high, the solvent does not evaporate until it reaches the counter electrode plate 23 and remains in the resin fiber 12. If the solvent remains in the resin fibers 12 as described above, after the vacuum heat insulation panel 14 is formed, the vapor of the solvent is released from the resin fibers 12 to reduce the degree of vacuum of the vacuum heat insulation panel 14, leading to a decrease in heat insulation. Further, if the solvent remains in the resin fiber 12, it takes a long time to dry, or the vapor of the solvent is released at the current pressure when the vacuum heat insulating panel 14 is formed, so that the time to reach the vacuum state becomes long. Cause a decline. Therefore, it is necessary to select the boiling point of the solvent according to the characteristics of the manufacturing apparatus 20.

  Similarly, the dielectric constant is a major factor in the formation of the resin fiber 12. In general, a substance having a large dielectric constant has a property of easily storing charges. For this reason, the solvent having a large dielectric constant that easily accumulates charges accumulates charges due to the voltage applied to the nozzle portion 22 and is easily attracted to the counter electrode plate 23 by an advertising effect. As a result, when a solvent having a large dielectric constant is used, there is an advantage that the outer diameter of the formed resin fiber 12 can be easily reduced sufficiently. Further, the resin fiber 12 is sprayed while applying a high voltage to the resin solution refined by the nozzle portion 22 and is collected on the counter electrode plate 23 by an electrostatic action while the solvent is evaporated. Therefore, by increasing the dielectric constant of the solvent, the solution containing the resin sprayed from the nozzle portion 22 is attracted to the counter electrode plate 23 with a strong force. As a result, the higher the dielectric constant of the solvent, the better the collection efficiency of the formed resin fibers 12. In addition, as above-mentioned, the formed nonwoven fabric 11 and the core material 10 may include the process of drying, before performing pressure reduction and evacuation as a vacuum heat insulation panel. The formed non-woven fabric 11 and the core material 10 may be dried by, for example, drying using a heating means or by leaving for a preset period. Thereby, the solvent which remains in the nonwoven fabric 11 and the core material 10 is removed, and the vacuum degree of a vacuum heat insulation panel can be hold | maintained for a long period of time.

Next, the performance comparison between the core material 10 using the resin fiber 12 formed by the electrospinning method of the present embodiment and the core material using the conventional glass fiber will be described with reference to FIG.
In Examples 1 to 3, resin fibers 12 formed by the electrospinning method of the present embodiment are used as the nonwoven fabric 11 constituting the core material 10. On the other hand, the comparative example 1 uses the conventional glass fiber for a core material. Moreover, the comparative example 2 uses the resin fiber 12 for the core material similarly to Example 1 to Example 3. In Example 1 and Comparative Example 2, polystyrene (PS) is used as a raw material for the resin fiber 12. In Example 2 and Example 3, polyamideimide (PAI) is used as a raw material for the resin fiber 12.

[Resin fiber]
PS as a raw material for the resin fiber 12 of Example 1 and Comparative Example 2 has a density, that is, a specific gravity of 1.05, which is smaller than 2.5 of the glass fiber of Comparative Example 1. Moreover, PAI used as the raw material of the resin fiber 12 of Example 2 and Example 3 is 1.42 and specific gravity is small compared with a glass fiber. Thereby, the vacuum heat insulation panel 14 which forms the core material 10 with the resin fiber 12 of Example 1- Example 3 can achieve weight reduction compared with the vacuum heat insulation panel using the conventional glass fiber.

  PS used as the raw material of the resin fiber 12 of Example 1 and Comparative Example 2 used dimethylformamide as a solvent. In the case of Example 1, PS as a raw material had an average molecular weight of 218,000 and was prepared as a solution having a concentration of 23 (wt%). In the case of Comparative Example 2, the raw material PS was prepared as a solution having an average molecular weight of 329,000 and a concentration of 18 (wt%). Moreover, PAI used as the raw material of the resin fiber 12 of Example 2 and Example 3 used N-methyl-2-pyrrolidone as a solvent. In the case of Example 2, PAI used as a raw material was prepared as a solution having a concentration of 14 (wt%). In the case of Example 3, PAI used as a raw material was adjusted as a solution having a concentration of 30 (wt%).

  The resin fibers 12 of Examples 1 to 3 and Comparative Example 2 were spun using an electrospinning method. At this time, the voltage applied to the nozzle part 22 was set to 40 (kV). The fiber diameter, that is, the outer diameter d of the obtained resin fiber 12 was 0.68 (μm) in Example 1, 0.45 (μm) in Example 2, and 0.80 (μm) in Example 3. . On the other hand, the glass fiber of Comparative Example 1 had an outer diameter d of 1 to 5 (μm). The outer diameter of Comparative Example 2 was 4.4 (μm). The resin fibers 12 of Examples 1 to 3 and Comparative Example 2 are one continuous fiber until each fiber formed by jetting from the plurality of nozzle portions 22 is completely spun, that is, until the formation of the nonwoven fabric 11 is completed. It was. Therefore, in the case of Example 1 to Example 3 and Comparative Example 2, the fiber length of the formed resin fiber 12 was sufficiently long to be 1000 times or more with respect to the outer diameter d. On the other hand, the glass fiber of the comparative example had a fiber length of less than 1 (mm).

  Thus, the heat insulation performance of the core material 10 made of the nonwoven fabric 11 of the resin fibers 12 spun by the electrospinning method was evaluated. The heat insulating performance was performed by comparing the core material 10 using the resin fiber 12 of Examples 1 to 3 and Comparative Example 2 and the core material using the conventional glass fiber of Comparative Example 1. The core material 10 using the resin fibers 12 of Examples 1 to 3 and Comparative Example 2 and the core material using conventional glass fibers were all formed as the vacuum heat insulating panel 14 under the same conditions. The heat insulation performance was compared using the formed vacuum heat insulation panel 14. The heat conductivity of the vacuum heat insulation panel 14 using the conventional glass fiber was 4.0 (mW / mK). The vacuum insulation panel 14 using this conventional glass fiber was evaluated as “◯: low thermal conductivity” and “Δ: thermal conductivity is equivalent”. As a result, Example 1 and Example 3 were evaluated as “Δ”, and the thermal conductivity was equivalent to that of the conventional glass fiber. The evaluation of Comparative Example 2 was also “Δ”. On the other hand, in Example 2, the evaluation was “◯”, and the heat insulation was higher than that of the conventional glass fiber.

  From the results of these Examples 1 to 3, the vacuum heat insulating panel 14 including the core material 10 formed of the resin fibers 12 having an outer diameter d of d <1 μm, regardless of the resin as the raw material, It has been clarified that the heat insulating property is improved as compared with the vacuum heat insulating panel 14 including the core material 10 formed of glass fiber. In Examples 1 to 3, since the specific gravity of the resin fiber 12 is smaller than that of the conventional glass fiber, the formed vacuum heat insulation panel 14 can be reduced in weight.

  Furthermore, when Example 2 and Example 3 are compared, Example 2 has a higher evaluation of thermal conductivity. This means that when the raw material of the resin fiber 12 is the same, the smaller the outer diameter d, the better the thermal conductivity. Therefore, by using the electrospinning method, the outer diameter d of the resin fiber 12 forming the core material 10 can be reduced, and the heat insulating property of the vacuum heat insulating panel 14 can be improved.

  Furthermore, in the case of Example 1 to Example 3, the nonwoven fabric 11 is formed while spinning the resin fiber 12 by the electrospinning method. Thereby, as for the resin fiber 12 which has a long fiber length, mutual entanglement becomes strong and the shape of the formed nonwoven fabric 11 is stabilized. Further, the nonwoven fabric 11 formed from the resin fibers 12 can be reduced in weight. The nonwoven fabric 11 having a stable shape and a light weight can be laminated in a plurality of layers. As a result, a lightweight and durable core material 10 can be manufactured using resin.

(refrigerator)
Next, a refrigerator using the vacuum heat insulation panel 14 will be described with reference to FIGS. 9 and 10.
As shown in FIG. 9, the refrigerator 40 includes a heat insulating box 41 having an open front surface. In the refrigerator 40, a refrigeration cycle (not shown) is attached to the heat insulating box 41. The refrigerator 40 also includes a partition plate (not shown) that partitions the heat insulation box 41 into a plurality of storage rooms, a heat insulation door (not shown) that covers the front of the storage room, and a drawer (not shown) that moves back and forth inside the storage room. Yes. The heat insulating box 41 of the refrigerator 40 includes an outer box 42, an inner box 43, and a vacuum heat insulating panel set 50 sandwiched between the outer box 42 and the inner box 43. The outer box 42 is formed of a steel plate, and the inner box 43 is formed of a synthetic resin.

  The vacuum heat insulation panel set 50 is divided corresponding to each wall portion of the heat insulation box 41 of the refrigerator 40. Specifically, the vacuum heat insulating panel set 50 is divided into a left wall panel 51, a right wall panel 52, a ceiling panel 53, a rear wall panel 54, and a bottom wall panel 55 as shown in FIG. The left wall panel 51, the right wall panel 52, the ceiling panel 53, the rear wall panel 54, and the bottom wall panel 55 are all configured by the vacuum heat insulating panel 14 described above. The left wall panel 51, the right wall panel 52, the ceiling panel 53, the rear wall panel 54 and the bottom wall panel 55 are assembled as a vacuum heat insulating panel set 50 and sandwiched between the outer box 42 and the inner box 43. A gap formed between the left wall panel 51, the right wall panel 52, the ceiling panel 53, the rear wall panel 54, and the bottom wall panel 55 constituting the vacuum heat insulation panel set 50 between the outer box 42 and the inner box 43. Is sealed with a heat insulating seal member (not shown). The seal member is formed of, for example, a foamable resin.

  Thus, the refrigerator 40 has the vacuum heat insulation panel set 50 which comprises the heat insulation box 41. FIG. The vacuum heat insulation panel set 50 is configured by the vacuum heat insulation panel 14 described above. Therefore, high heat insulation performance can be secured while further reducing the thickness and weight.

  The core material of the vacuum heat insulation panel according to the present embodiment has a configuration in which a plurality of nonwoven fabrics are laminated, and the nonwoven fabric is composed of thermosetting resin fibers made of a thermosetting resin. According to this configuration, even when the nonwoven fabric is made of resin fibers, the strength of the resin fibers can be ensured, sufficient gaps can be secured even after decompression, and the heat insulation performance is reduced. It can be avoided. As illustrated in FIG. 11, the core material of the vacuum heat insulation panel mainly composed of non-woven fabric composed of fibers is compressed as the inside of the vacuum heat insulation panel is depressurized, and the internal porosity decreases. Here, the porosity after decompression when the nonwoven fabric is composed of thermosetting resin fibers is smaller than the porosity after decompression when the nonwoven fabric is composed of glass fibers, but the nonwoven fabric other than the thermosetting resin It becomes larger than the porosity after decompression when it is made of resin fibers such as polystyrene.

  Therefore, according to the core material of the vacuum insulation panel in which the nonwoven fabric is composed of thermosetting resin fibers, the deterioration of the thermal insulation performance is suppressed more than the core material of the vacuum insulation panel in which the nonwoven fabric is composed of resin fibers other than the thermosetting resin. Can do. Moreover, according to the core material of the vacuum heat insulation panel which comprised the nonwoven fabric with the thermosetting resin fiber, since the resin fiber has higher thermal conductivity than the glass fiber, the porosity is smaller than when the nonwoven fabric is made of glass fiber. Even if it becomes, the heat insulation performance equivalent to the case where it comprises with glass fiber can be exhibited.

  As mentioned above, although embodiment of this invention was described, these embodiment is shown as an example and is not intending limiting the range of invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  In the drawings, 10 is a core material, 11 is a nonwoven fabric, 12 is a resin fiber, 14 is a vacuum heat insulation panel, 15 is an aluminum foil, 16 is a glass fiber layer, 22 is a nozzle part, 23 is a counter electrode, and 40 is a refrigerator.

Claims (16)

A core material of a vacuum insulation panel in which a plurality of nonwoven fabrics are laminated,
The said nonwoven fabric is a core material of the vacuum heat insulation panel comprised with the thermosetting resin fiber which consists of thermosetting resin.   The said thermosetting resin fiber is a core material of the vacuum heat insulation panel of Claim 1 containing the main material which consists of a thermosetting resin material, and the hardening | curing agent which hardens the said main material.   The core material of the vacuum insulation panel according to claim 1 or 2, wherein the nonwoven fabric is subjected to a drying process for removing the solvent.   The core material of the vacuum heat insulation panel according to any one of claims 1 to 3, wherein the thermosetting resin fiber is a fiber made of an epoxy resin.   The core material of the vacuum heat insulation panel according to any one of claims 1 to 4, wherein the thermosetting resin fiber has an outer diameter d of d <1 µm.   The thermosetting resin fiber is an electrospinning method in which a resin dissolved in a solvent is injected from the nozzle portion toward the counter electrode plate between a nozzle portion to which a voltage is applied and a counter electrode plate facing the nozzle portion. The core material of the vacuum heat insulation panel of any one of Claim 1 to 5 currently formed.   The core material of the vacuum heat insulating panel according to any one of claims 1 to 6, wherein the thermosetting resin fiber has a density lower than that of glass.   The core material of the vacuum heat insulation panel of any one of Claim 1 to 7 in which the inorganic type filler is added to the said thermosetting resin fiber.   The core material of the vacuum heat insulation panel according to any one of claims 6 to 8, wherein the resin and the solvent which are materials of the thermosetting resin fiber have compatibility.   The said nonwoven fabric is a core material of the vacuum heat insulation panel of any one of Claim 1 to 9 laminated | stacked 100 or more sheets.   The said nonwoven fabric is a core material of the vacuum insulation panel of any one of Claim 1 to 10 currently formed with the 2 or more types of resin fiber containing the said thermosetting resin fiber.   The core material of the vacuum heat insulation panel of any one of Claim 1 to 11 provided with the aluminum foil which contact | connects the one surface side of the said nonwoven fabric laminated | stacked in multiple numbers.   The core material of the vacuum heat insulation panel according to any one of claims 1 to 12, wherein the thermosetting resin fiber has a shape curved at random.   The core material of the vacuum heat insulation panel according to any one of claims 1 to 13, wherein the thermosetting resin fiber is a long fiber having a length of 1000 times or more with respect to an outer diameter thereof.   A vacuum heat insulation panel provided with the core material of the vacuum heat insulation panel of any one of Claim 1 to 14.   A refrigerator provided with the vacuum heat insulation panel of Claim 15.

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