JP2004011755A - Vacuum heat-insulating material, its manufacturing method, and insulation box in which vacuum heat-insulating material is used - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vacuum heat-insulating material and its manufacturing method in which, even after the heat-insulating material is manufactured, a recess and grooves can be formed on the surface by an ordinary forming process without causing damages such as tears and pinholes on the covering material of a laminate film, suppressing warping, sink, and defective forming, which are caused in association with formation of the recess and grooves. <P>SOLUTION: The recess is formed on the surface of the vacuum heat-insulating material, in which a plate core-material having an inside layer more flexibly than the skin layer is used. The grooves are formed in the vicinity of a rear position opposite to a recess-opening end. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a vacuum heat insulating material that can be used as a heat insulating material for heat insulating containers, home electric appliances, vending machines, vehicles, houses, and the like.
[0002]
[Prior art]
Vacuum insulation material is very rigid because the inside of the jacket material is decompressed and atmospheric pressure is applied to the entire surface, and it is made of a thin film when it is later formed, such as by bending, forming recesses and grooves. Since the outer cover material is apt to be damaged, it is used as a flat plate in most application examples, and a plurality of sheets are divided and used depending on the shape of an application portion.
[0003]
Then, in order to further expand the applicable range of the vacuum heat insulating material, a method of forming the vacuum heat insulating material is disclosed in Japanese Patent Publication No. 6-105152. The contents are as follows: put the vacuum heat insulating material in a vacuum vessel, reduce the ambient atmosphere, remove the atmospheric pressure added to the film surface, soften the vacuum heat insulating material, mold it, and further maintain its shape A vacuum heat insulating material is obtained by returning the ambient atmosphere to normal pressure, and can be easily formed without damaging the film.
[0004]
[Problems to be solved by the invention]
However, in order to form the vacuum heat insulating material by the conventional method, it is necessary to evacuate the inside of the vacuum container each time the molding is performed, and to return to normal pressure after the molding. Further, since a molding die must be provided in the vacuum vessel, there is a problem that the apparatus becomes complicated and costs increase.
[0005]
In addition, even if the recesses and grooves are formed from the top of the jacket material after the vacuum insulation material is manufactured, by taking measures such as softening the core material or strengthening the jacket material, the jacket is pressed by pressure. There is a problem that the material is pulled and the vacuum heat insulating material warps toward the molding surface.
[0006]
Further, there is a problem that the tension of the jacket material makes the shape of the opening end of the concave portion or the groove indefinite, which causes the thickness of the vacuum heat insulating material to be reduced mainly at the molded portion.
[0007]
Furthermore, in the case of a concave portion having a wide bottom surface, there is a problem that sink marks occur in the relative position of the back surface.
[0008]
The present invention solves the above-mentioned problems, and provides a vacuum heat insulating material capable of forming a concave portion or the like from above a jacket material with a normal device, improves the productivity, and reduces the cost without using a normal device. An object of the present invention is to provide a heat insulating material and a manufacturing method, and to provide a heat insulating box using a vacuum heat insulating material and having a small heat loss.
[0009]
[Means for Solving the Problems]
The vacuum heat insulating material according to the present invention includes a core material, and a covering material that covers the core material and seals the inside of the core by decompressing the inside of the core material. Forming a concave portion having at least one groove on the back surface, and forming a groove against the tension of the outer cover material on the back surface corresponding to the concave portion on the front surface. It is formed to prevent warpage.
[0010]
Further, the present invention is based on the fact that the core material is formed into a flat plate shape in which the inner layer from the skin layer is flexible, and the skin layer is provided with appropriate rigidity within a range that does not damage the jacket material. By pressing the material from above, it is possible to form the concave portion and prevent warpage after the forming.
[0011]
Further, in the present invention, by molding a fiber material, a flat core material whose layer inside the skin layer is flexible can be easily produced.
[0012]
Also, the present invention is to form a groove near the position of the back surface opposite to the opening end of the recess of the front surface of the vacuum heat insulating material, thereby preventing warpage and simultaneously forming the recess and the opening surface of the opening of the recess. The concave portion is formed into a predetermined shape by forming a groove by applying pressure also to the relative position of.
[0013]
Further, the present invention is to prevent the opening end on the side close to the recess of the groove on the back surface from being separated from the relative position of the back surface of the opening end of the recess by more than the opening width of the groove on the back surface, Pressing from the back surface works effectively, and a predetermined shape of the opening end of the concave portion can be reliably obtained.
[0014]
Further, the method for producing a vacuum heat insulating material according to the present invention comprises, after covering a core material obtained by molding a fibrous material into a flat plate having a layer on the inner side of the skin layer with a covering material, depressurizing the inside and sealing the outer material. A concave part on the front side and a groove on the back side are formed by pressure molding from the top of the workpiece. Since the inner layer of the core material is flexible, the pressing pressure of the mold can be reduced even after the vacuum insulation material is manufactured. A groove can be formed on the surface of the vacuum heat insulating material from above the outer cover material by making it smaller, thereby suppressing damage to the outer cover material and preventing damage such as breakage and pinholes. That is, the groove can be formed using a normal apparatus in the atmosphere, so that the productivity can be improved and the cost can be suppressed.
[0015]
The heat insulating box using the vacuum heat insulating material of the present invention is provided with the vacuum heat insulating material of the present invention in a space formed by the outer box and the inner box, and the vacuum heat insulating material has a reinforcement existing inside the space. By forming recesses in accordance with the projections such as parts, pipes and wiring, it is possible to use in places that could not be applied conventionally, and in the past, multiple vacuum insulation materials were used avoiding the projections Since the heat loss generated from the joint or the like can be prevented, the heat insulating performance of the heat insulating box can be improved.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of a vacuum heat insulating material according to the present invention will be described with reference to the drawings.
[0017]
(Embodiment 1)
FIG. 1 is a schematic sectional view of a vacuum heat insulating material according to Embodiment 1 of the present invention. FIG. 2 is a plan view of the vacuum heat insulating material shown in FIG.
[0018]
1 and 2, a vacuum heat insulating material 1 is composed of a core material 2 and a jacket material 3 made of a gas barrier film, and the inside thereof is decompressed. A concave portion 4 is formed on the front surface A of the vacuum heat insulating material 1, and two grooves 5a and 5b are formed on the back surface B. Around the vacuum heat insulating material 1, a fin portion 3a of the outer cover material 3 which has been decompressed and thermally fused is present around.
[0019]
It should be noted that the front surface A and the back surface B indicate that they are opposing surfaces, and do not limit the present invention further.
[0020]
FIG. 3 is a schematic cross-sectional view of the core material of the vacuum heat insulating material according to the first embodiment of the present invention. The core material 2 is obtained by molding a fiber material using a binder 6, and the concentration of the binder 6 is the skin of the core material 2. The layer 2a is the highest, and the intermediate layer 2b, and the center layer 2c and the inner layer are lower.
[0021]
The core 2 and the jacket 3 will be described in detail.
[0022]
First, a predetermined amount of glass wool having an average fiber diameter of 5 μm is laminated on the core material 2 to form a fiber laminate. The binder 6 is prepared by dissolving 3 parts by weight of boric acid in 97 parts by weight of water with respect to 100 parts by weight of glass wool to obtain 100 parts by weight of a boric acid aqueous solution. This boric acid aqueous solution is sprayed on the surface of the fiber laminate with a spray device, and once pressed and infiltrated at room temperature, pressed in a hot air circulating furnace at 350 ° C. for 20 minutes, and has a thickness of 15 mm. A molded body having a density of 230 kg / m ³ was obtained, and was cut into a length of 180 mm and a width of 180 mm to obtain a core material 2.
[0023]
Even when the boric acid aqueous solution is sprayed onto the fiber laminate and pressed, the aqueous layer is not completely penetrated into the inner layer, so that the aqueous solution is diffused into the inner layer by the steam during the heating and compression. Thereby, the inner layer of the core material 2 is softened by binding with a small amount of the binder 6, and becomes a molded body in which the amount of the binder increases toward the skin layer 2a. As a result of the analysis, about 28% of the entire binder 6 is present in the skin layer 2a of 1 mm each on the front and back surfaces of the core material 2, and about 18% of the binder 6 is present on the intermediate layer 2b of 4 mm inside each. 8% was present in the 5 mm central layer 2c.
[0024]
The outer cover material 2 is formed by laminating the heat-sealed surfaces of two laminated films and forming a bag on three sides by heat-sealing.
[0025]
One of the two laminated films is a 50 μm-thick linear low-density polyethylene film (hereinafter referred to as LLDPE) as a heat-sealing layer, and a 15 μm-thick ethylene-polyvinyl alcohol copolymer film as a gas barrier layer. A film in which a 500 mm thick aluminum vapor-deposited film is formed on an EVOH (hereinafter referred to as EVOH) and a 500 mm thick aluminum vapor-deposited film is formed on a 12 μm-thick polyethylene terephthalate film (hereinafter referred to as PET). In this case, LLDPE of the heat sealing layer and EVOH of the gas barrier layer are dry-laminated.
[0026]
Another one is LLDPE having a thickness of 50 μm as a heat sealing layer, an aluminum foil having a thickness of 6 μm as a gas barrier layer thereon, a nylon having a thickness of 12 μm as a protective layer thereon, and a thickness of 12 μm as an outermost layer. It is made of nylon.
[0027]
Next, a method for manufacturing the vacuum heat insulating material 1 will be described.
[0028]
As the core material 2, a core material 2 in which the binder concentration of the inner layer is lower than that of the skin layer and the inside is softened is used, and after drying the core material 2 at 140 ° C. for 1 hour, the bag-shaped outer material 3 is formed. The product inserted therein was placed in a vacuum chamber to depressurize the inside, and in this state, the opening was sealed by heat fusion and taken out of the vacuum chamber.
[0029]
The thermal conductivity of the vacuum heat insulating material 1 as described above was 0.0020 W / mK at an average temperature of 24 ° C.
[0030]
Thereafter, the vacuum heat insulating material 1 was pressed by press molding using a mold to simultaneously form the concave portion 4 on the front surface A and the grooves 5a and 5b on the back surface B.
[0031]
The concave portion 4 has a substantially planar bottom surface 4Y, and has dimensions of opening width W40 mm × bottom width Y20 mm × depth D5 mm, and substantially the center of the vacuum heat insulating material 1 is formed over the entire width. With respect to the metal mold pressed into contact with the jacket material 3, the corners for forming the bottom surface of the concave portion 4 are given an R shape (10R) to prevent damage.
[0032]
The dimensions of the grooves 5a, 5b were such that the opening width V4mm × the depth U2mm, and the tops Pa, Pb of the grooves 5a, 5b were located near the position of the back surface B facing the recess opening ends 4a, 4b, respectively. In this position, if the tops Pa and Pb are in the vicinity of the positions facing the recess opening ends 4a and 4b, a sufficient pressing effect from the back surface B can be obtained. If the closer opening ends 5c and 5d are separated from the relative positions of the back surfaces B of the recess opening ends 4a and 4b by more than the opening width V of the grooves 5a and 5b, a sufficient effect cannot be obtained.
[0033]
In the recess 4 and the grooves 5a and 5b formed in this manner, there was no damage such as pinholes or breaks in the jacket material 3. Also, there was no warpage of the vacuum heat insulating material 1 due to the concave portion 4 and no sinking of the back surface B facing the concave portion 4, and the concave portion opening ends 4a and 4b could be formed into a predetermined shape.
[0034]
Further, the thermal conductivity of the vacuum heat insulating material 1 was not changed except for the concave portion 4 and the grooves 5a and 5b. Furthermore, to confirm the reliability over time, the deterioration of the heat insulating material was evaluated by an accelerated test. The thermal conductivity under the condition of 10 years passed was 0.014 W / mK at an average temperature of 24 ° C. There was no difference from the one without molding.
[0035]
That is, since the binder concentration of the inner layer of the core material is low and the inside is flexible, there is no problem in forming the concave portion or the groove by pressure molding after the vacuum heat insulating material is produced, and a normal device is used in the atmosphere. Thus, the recesses and grooves can be formed with relatively small pressure, so that the productivity can be improved and the cost can be suppressed.
[0036]
The material and configuration of the vacuum heat insulating material are not limited to the above.
[0037]
As the fibrous material, known materials can be used, but from the viewpoint of heat resistance during heating and compression, inorganic fibers are preferably used. As the inorganic fiber, glass wool, glass fiber, alumina fiber, silica-alumina fiber, silica fiber, rock wool, silicon carbide fiber and the like can be used.
[0038]
The fiber diameter is not particularly specified, but is preferably 0.1 μm to 10 μm from the viewpoint of heat insulation performance and productivity of raw cotton.
[0039]
As the binder, boric acid-based compounds include sodium borates such as boric acid, metaboric acid, boron oxide, each hydrate or anhydride of sodium tetraborate, ammonium borate, lithium borate, magnesium borate , Calcium borates, aluminum borates, zinc borates, perborates, alkylboric acids, boroxine derivatives and the like.
[0040]
Examples of the phosphoric acid compound include phosphoric acid, phosphorus oxide such as diphosphorus pentoxide, and phosphates such as primary phosphate, secondary phosphate, tertiary phosphate, pyrophosphate, and tripolyphosphate. And sodium salts, potassium salts, ammonium salts, magnesium salts, aluminum salts and the like.
[0041]
Among these, a glass-forming substance or a water-soluble substance is preferable, and examples thereof include boric acid, metaboric acid, boron oxide, borax, phosphoric acid, aluminum monophosphate, and sodium hexametaphosphate.
[0042]
One or a mixture of two or more of the above may be used, or other binders may be mixed or diluted to use as a binder for a molded article.
[0043]
Next, a method for adhering a binder will be described.
[0044]
Although not particularly specified, the binder is adhered by applying or spraying a binder or a diluent thereof, immersing the core material in the binder or a diluent thereof, or using a papermaking method.
[0045]
More specifically, in addition to the method of spraying a molded article to a certain degree as described above, if the fiber is a fiber, a binder or a diluent thereof is sprayed at the time of fiberization, and for example, the binder concentration is high in a skin layer serving as a core material. By placing fibers with a low binder concentration in the inner layer, and fibers with no binder in the center layer, and solidifying the fiber laminate by compression heating, etc., in the thickness direction of the molded body, It is also possible to obtain flat plates having different binder concentrations.
[0046]
It is desirable that the binder be attached such that the solid content of the binder is 0.5 wt% or more and 20 wt% or less with respect to the core material. This is because, when the amount of the binder increases, there is a concern that the amount of gas generated from the binder and the solid thermal conductivity may increase, which may adversely affect the heat insulating performance of the vacuum heat insulating material.
[0047]
The binder concentration may be different as long as at least a certain part and a certain part have different concentrations in the thickness direction of the core material. It is intended to have the effect of imparting each.
[0048]
In addition, the fact that the binder concentration of the skin layer of the core material is high can improve the flatness of the surface when a vacuum heat insulating material is used.
[0049]
As another method, there is also a method of dissolving a component instead of a binder by the action of water without using a binder, but in this case, the fiber material is preferably a material containing silica among inorganic fibers, Among them, glass wool is most preferable.
[0050]
Furthermore, the density of the core material is desirably pressurized so as to ^{100kg / m 3 ~400kg / m 3} , or may have a density different inside core.
[0051]
When the density is less than 100 kg / m ^3, it is difficult to maintain the shape as a molded body, and when the density is more than 400 kg / m ³ , it becomes too hard, and it becomes difficult to form grooves.
[0052]
Next, the covering material will be described.
[0053]
The jacket material has at least a gas barrier layer and a heat sealing layer, and may be provided with a surface protective layer and the like as necessary.
[0054]
As the gas barrier layer, a metal foil, an inorganic oxide, a plastic film on which diamond-like carbon is deposited, or the like can be used, but is not particularly limited as long as it is used for the purpose of reducing gas permeation.
[0055]
As the metal foil, foil such as aluminum, stainless steel, and iron can be used.
[0056]
The material of the plastic film serving as a base material on which metal or the like is deposited is not particularly specified, but polyethylene terephthalate, ethylene-vinyl alcohol copolymer resin, polyethylene naphthalate, nylon, polyamide, polyimide, and the like are preferable.
[0057]
The material for metal deposition on the plastic film is not particularly specified, such as aluminum, cobalt, nickel, zinc, copper, silver, or a mixture thereof.
[0058]
Further, as a material for depositing the inorganic oxide on the plastic film, there are silica, alumina and the like.
[0059]
Further, as the heat sealing layer, a low-density polyethylene film, a chain low-density polyethylene film, a high-density polyethylene film, a polypropylene film, a polyacrylonitrile film, a non-oriented polyethylene terephthalate film, an ethylene-vinyl alcohol copolymer film, or Can be used, but is not particularly specified.
[0060]
As the surface protective layer, a stretched product of a nylon film, a polyethylene terephthalate film, a polypropylene film, or the like can be used. Further, when a nylon film or the like is provided on the outside, flexibility is improved, and bending resistance and the like are improved.
[0061]
The above films can be laminated and used as a covering material.
[0062]
(Embodiment 2)
Another embodiment of the concave portion and the groove formed in the vacuum heat insulating material will be described.
[0063]
4 and 5 are schematic cross-sectional views of a vacuum heat insulating material according to another embodiment of the present invention.
[0064]
In FIG. 4, a shallow groove 45 having a wide bottom surface 45Y is formed on the back surface, opposite to the concave portion 44 on the front surface. As a result, the vacuum heat insulating material 41 did not warp, and the concave opening ends 44a and 44b also had a predetermined shape. However, since the thickness of the concave portion 44 of the vacuum heat insulating material 41 was small, a slight decrease in heat insulating performance was recognized.
[0065]
In FIG. 5, two recesses 54, 55 are formed in the front surface in close proximity, and a plurality of grooves 56, 57, 58 on the back surface are formed. Here, the groove 57 is formed so as to be used also as opposed to the two concave opening ends 54b and 55b. The interval LA between the concave opening ends 54b and 55b is determined by the opening width VL of the groove 57 and the opening end of the groove. This is the sum of the distances LBa and LBb between 57a and 57b and the two relative positions, and both of the distances LBa and LBb are smaller than the opening width VL of the groove 57.
[0066]
As a result, the vacuum heat insulating material 51 does not warp, and the concave opening ends 54a, 54b, 55a, and 55b also have a predetermined shape, and no sink marks are observed on the back surfaces facing the concave portions 54, 55. Was.
[0067]
FIG. 6 is a plan view of a vacuum heat insulating material according to another embodiment of the present invention.
[0068]
6, the concave portion 64 on the front surface does not extend over the entire width of the vacuum heat insulating material 61 as compared with FIG. 2 of the first embodiment. In such a case, the groove 65 on the back surface is formed in an annular shape.
[0069]
As a result, there was no warpage of the vacuum heat insulating material 61, the concave opening end 64a had a predetermined shape, and no sink mark was observed on the back surface facing the concave 64.
[0070]
The embodiments described above can also be applied in a form in which they are combined.
[0071]
(Embodiment 3)
A method of manufacturing the vacuum heat insulating material according to the present invention by molding the core material 2 on glass wool using water will be described.
[0072]
Raw cotton wool having an average fiber diameter of about 4 μm to 6 μm manufactured by a centrifugal method is cut into a predetermined size, and a predetermined amount of cotton is laminated. Neutral ion-exchanged water having a pH value of 6 or more and 8 or less is sprayed so as to adhere almost uniformly to the surface of the collected cotton laminate. The spray amount was 1.5 to 2.0 times the weight of the cotton collection laminate.
[0073]
The cotton laminate laminated with ion-exchanged water is compressed at room temperature to diffuse and permeate water into the cotton laminate, and the diffusion-permeated laminate is placed in a metal jig heated to 380 ° C. Then, a metal holding plate was placed from above, pressed at a high temperature by a hot press, held for 10 minutes or more, and dried to produce a core material 2 having a thickness of 15 mm.
[0074]
In the obtained core material 2, the glass fibers are oriented perpendicularly to the heat transfer direction by repeating the compression, so that the glass fibers are less likely to be torn in the laminating direction and have high reliability.
[0075]
Further, the prepared core material 2 having a thickness of 15 mm is cut into a length of 180 mm and a width of 180 mm to obtain a core material 2. The core material 2 is dried in a drying oven at 150 ° C. for about 60 minutes to remove moisture remaining after molding.
[0076]
The dried core material 2 is taken out of the drying furnace, the adsorbent is quickly stored in the recess formed in the core material 2 in advance, and the core material 2 containing the adsorbent is inserted into the jacket material 3 and placed in the vacuum chamber. Place. After the inside of the vacuum chamber is evacuated to a vacuum degree of 1.33 Pa or less, the opening of the jacket 3 is sealed in the vacuum chamber by heat fusion. The completed product was taken out of the vacuum chamber, and a vacuum heat insulating material 1 was obtained.
[0077]
In addition, although the ion-exchanged water is used for the water sprayed on the cotton collection laminate, the water is not particularly limited, and may be distilled water, alkaline ionized water, mineral water, filtered water, or tap water.
[0078]
Further, as the characteristic values of water, hardness, total alkalinity, residual chlorine concentration, basic nitrogen such as nitrite, nitrate, and ammonium, ion concentration such as phosphoric acid, copper, and iron are not particularly limited. However, ion-exchanged water is preferable in terms of heat insulation performance.
[0079]
Thereafter, the method of forming the concave portion and the groove in the vacuum heat insulating material 1 is the same as that of the first embodiment. However, when molded using water, a softer core material is obtained than when a binder is used. Less damage to the jacket material. Further, since no binder is contained, regeneration and reuse of glass wool is easy, and the load on the environment is small.
[0080]
(Embodiment 4)
An example in which the present invention is applied to a refrigerator as a heat insulating box using the vacuum heat insulating material of the present invention will be described.
[0081]
FIG. 7 is a schematic side sectional view of a refrigerator according to the third embodiment, and FIG. 8 is an exploded perspective view of a main part of the refrigerator according to the third embodiment.
[0082]
7 and 8, reference numeral 7 denotes a refrigerator, which is composed of an outer box 8 and an inner box 9, and a plurality of vacuum heat insulating materials are used in a space inside a wall of the box, and a remaining space portion is provided. Is filled with a rigid urethane foam 10 using cyclopentane as a foaming agent.
[0083]
The refrigerator 7 is divided into four rooms. The refrigerator 7 has a refrigerator room 11 which is maintained at a refrigeration temperature of about 5 ° C. from the upper stage, and a vegetable room 11a for storing foods which do not want to be dried. There is a freezing room 11b for cooling to a freezing temperature of about −20 ° C. These chambers are partitioned by heat insulating partition plates 12 and 13.
[0084]
The vacuum heat insulating material is disposed on the top surface, the rear surface, the left and right side surfaces, the bottom surface, the four doors, and the heat insulating partition plates 12 and 13 of the refrigerator 7. Vacuum insulation materials 1A, 1B, 1C, 1D used on the top surface, the back surface, and the left and right side surfaces are formed by forming a piping groove 15 along the shape of a refrigerant pipe 14 having a diameter of 4 mm along the inner surface of the outer box. Then, it was stuck on the inner surface of the outer box by hot melt. The shape of the piping groove 15 is the same as the groove in the first embodiment. Further, a normal vacuum heat insulating material 1 having no groove was used for each door, and a vacuum heat insulating material 1 having a hole 16 for penetrating a drain pipe was used on the bottom surface.
[0085]
As a result, the coverage of the vacuum heat insulating material reaches up to 70% of the outer box surface area of the refrigerator 7.
[0086]
When the power consumption of the refrigerator 7 thus obtained was measured, it was confirmed that the coverage of the vacuum heat insulating material was reduced by about 20% as compared with the case where the coverage was 30%.
[0087]
In other words, even in places where a single piece of vacuum heat insulating material could not be used conventionally, such as when there are protrusions such as pipes inside the heat insulating wall of a refrigerator, a groove is formed in the vacuum heat insulating material according to its shape. By doing so, it becomes possible to use it, and since it can be applied with one piece, the heat loss from the joint part of the vacuum heat insulating material can be reduced, so that the heat insulating performance of the refrigerator can be greatly improved.
[0088]
In addition, as a place where the vacuum heat insulating material is applied in the refrigerator, a place where the temperature difference between the inside and outside of the refrigerator is large is more effective, but a coverage of 50% or more with respect to the outer box surface area is desirable. When the coverage is 50% or more, the influence of the heat loss from the rigid urethane foam part is reduced, and the heat insulating effect by applying the vacuum heat insulating material becomes dominant, so that efficient heat insulating becomes possible.
[0089]
Thus, by applying the vacuum heat insulating material of the present invention, a refrigerator excellent in energy saving can be provided.
[0090]
Further, since the vacuum heat insulating material of the present invention has excellent heat insulating performance, it is possible to make the heat insulating wall thinner, so that it is possible to achieve space saving of the refrigerator or increase in the refrigerator internal volume.
[0091]
Further, since the core material of the vacuum heat insulating material is inorganic fiber, it is nonflammable, and is excellent in terms of refrigerator safety.
[0092]
As described above, the improvement of the heat insulating performance by the vacuum heat insulating material of the present invention can be confirmed in various heat insulating boxes, and in addition to various cold insulating containers such as water heaters, rice cookers, and cooler boxes, vending machines, vehicles, or homes. It can also be applied as a heat insulation panel for equipment and the like.
[0093]
【The invention's effect】
As described above, the vacuum heat insulating material according to the present invention includes a core material, and a jacket material that covers the core material and seals the inside by reducing the pressure, and has a substantially planar shape on the flat front surface. A recess having a bottom surface of a predetermined width is formed, and one or more grooves are formed on the back surface, and the outer surface of the jacket material is also formed on the back surface corresponding to the recess on the front surface. By forming a groove against tension, warpage can be prevented.
[0094]
In addition, the present invention is a material in which the core material is formed into a flat plate with a layer inside the skin layer being flexible, and the skin layer has an appropriate rigidity within a range that does not damage the jacket material. By applying pressure from above on the jacket material with the device, it is possible to form the concave portion, thereby improving productivity and preventing warpage after the molding.
[0095]
Further, according to the present invention, by molding a fibrous material, a flat plate-shaped core material whose layer inside the skin layer is flexible can be easily produced.
[0096]
Also, the present invention is to form a groove near the position of the back surface opposite to the opening end of the recess of the front surface of the vacuum heat insulating material, thereby preventing warpage and simultaneously forming the recess and the opening surface of the opening of the recess. The concave portion can be formed in a predetermined shape by forming a groove by applying pressure also to the relative position of.
[0097]
Further, the present invention is to prevent the opening end on the side close to the recess of the groove on the back surface from being separated from the relative position of the back surface of the opening end of the recess by more than the opening width of the groove on the back surface, The pressure from the back surface effectively acts, and a predetermined shape of the opening end of the concave portion can be reliably obtained.
[0098]
Further, the method for producing a vacuum heat insulating material according to the present invention comprises, after covering a core material obtained by molding a fibrous material into a flat plate having a layer on the inner side of the skin layer with a covering material, depressurizing the inside and sealing the outer material. A concave part on the front side and a groove on the back side are formed by pressure molding from the top of the workpiece. Since the inner layer of the core material is flexible, the pressing pressure of the mold can be reduced even after the vacuum insulation material is manufactured. A groove can be formed on the surface of the vacuum heat insulating material from above the outer cover material by making it smaller, thereby suppressing damage to the outer cover material and preventing damage such as breakage and pinholes. That is, the groove can be formed using a normal apparatus in the atmosphere, so that the productivity can be improved and the cost can be suppressed.
[0099]
The heat insulating box using the vacuum heat insulating material of the present invention includes the vacuum heat insulating material of the present invention in a space formed by the outer box and the inner box. By forming recesses and grooves in this vacuum heat insulator in accordance with the protrusions such as reinforcements and pipes and wiring existing inside the space, it is possible to use in places that could not be applied conventionally, and conventionally By using a plurality of vacuum heat insulating materials avoiding the protruding portions, and by being able to prevent heat loss generated from the joints thereof, it is possible to provide a heat insulating box body with greatly improved heat insulating performance. You can do it.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view of a vacuum heat insulating material according to a first embodiment of the present invention. FIG. 2 is a plan view of the vacuum heat insulating material shown in FIG. 1. FIG. FIG. 4 is a schematic cross-sectional view of a vacuum heat insulating material according to another embodiment of the present invention. FIG. 5 is a schematic cross-sectional view of a vacuum heat insulating material according to another embodiment of the present invention. FIG. 7 is a schematic plan view of a refrigerator according to a fourth embodiment of the present invention. FIG. 8 is an exploded perspective view of a main part of a refrigerator according to a fourth embodiment of the present invention. Description]
1, 1A, 1B, 1C, 1D, 41, 51, 61 Vacuum heat insulating material 2 Core material 2a Skin layer 3 Jacket material 4, 44, 54, 55, 64 Concave portions 4a, 4b, 44a, 44b, 54a, 54b, 55a, 55b, 64a Recessed opening end 4Y Bottom surface 5a, 5b, 45, 56, 57, 58, 65 Groove 5c, 5d Opening end 7 Refrigerator 8 Outer box 9 Inner box 15 Piping groove A Front surface B Back surface V, VL opening width

Claims (7)

A core material, and a covering material that covers the core material and seals the inside of the core material by decompressing the inside of the core material, and forming a concave portion having a substantially planar shape and a bottom surface of a predetermined width on a flat front surface; Vacuum insulation, characterized in that at least one groove is formed in the vacuum insulation material. 2. The vacuum heat insulating material according to claim 1, wherein the core material is formed by forming a layer inside the skin layer into a flexible flat plate. 3. The vacuum heat insulating material according to claim 1, wherein the core material is formed by molding a fiber material. The vacuum heat insulating material according to any one of claims 1 to 3, wherein a groove is formed near the position of the back surface facing the opening end of the concave surface of the front surface. 5. The vacuum heat insulating material according to claim 4, wherein the opening end of the groove on the back surface on the side close to the concave portion does not move outward with respect to the relative position of the back surface of the opening end of the concave portion more than the opening width of the groove. . A core material obtained by molding a fibrous material into a flat plate having a layer on the inner side of the skin layer is covered with a covering material, and the inside is decompressed and sealed. A method of manufacturing a vacuum heat insulating material, comprising forming a concave portion on a front surface and a groove on a back surface. 6. An outer box, an inner box, and a vacuum heat insulating material provided in a space formed by the outer box and the inner box, wherein the vacuum heat insulating material is any one of claims 1 to 5. A heat-insulating box body using a vacuum heat-insulating material as described above.

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