JP2014202322A - Vacuum heat insulating material - Google Patents

Abstract

The adsorbent is difficult to form irregularities and has high surface smoothness, and can fully exhibit the original adsorption performance of the adsorbent and maintain its heat insulation performance over a long period of time. Provide vacuum insulation material that can be used. A laminate having a structure in which a core material layer 2 formed of a core material made of an inorganic fiber mat and an adsorbent layer 4 formed of a granular adsorbent are laminated is provided with a gas barrier packaging. The vacuum heat insulating material 1 is housed in a bag 6 and vacuum-packed. Adsorbent pack in which the laminate is enclosed in a hard core layer 8 formed of a hard core material, a soft core material layer 10 formed of a soft core material, and an adsorbent made of a gas permeable sheet. And the adsorbent layer 4 is formed so that the soft core layer 10 is in contact with at least one surface of the adsorbent layer 4, and at least one surface of the adsorbent layer 4 is a soft core material. It has a structure covered by the layer 10. [Selection] Figure 1

Description

  The present invention relates to a vacuum heat insulating material in which a core material made of an inorganic fiber mat is housed in a gas barrier packaging bag and vacuum packaged. More specifically, the present invention relates to a vacuum heat insulating material containing a granular adsorbent in addition to the core material.

  Conventionally, as a vacuum heat insulating material used in a heat insulating box (a frame loaded with a vacuum heat insulating material) such as a refrigerator, a core material made of an inorganic fiber mat is housed in a gas barrier packaging bag and vacuum packed. A vacuum insulation material is known. For example, a vacuum heat insulating material is known in which a core material in which inorganic fibers such as glass fibers are laminated is covered with an outer bag and the inner pressure of the outer bag is reduced (Patent Document 1).

  Further, in the vacuum heat insulating material as described above, in order to maintain the performance for a long period of time, it has been proposed to store an adsorbent that adsorbs gas and moisture together with the core material inside the packaging bag. For example, a manufacturing method of a vacuum heat insulating material in which a core material using an inorganic fiber and a gas adsorbent are housed in a bag made of a gas barrier film and the inside thereof is decompressed and sealed has been proposed (Patent Document 2).

  Furthermore, as an adsorbent to be housed together with the core material in the vacuum heat insulating material as described above, for example, a granular or powdery adsorbent such as calcium oxide is combined with a soft resin as a binder, and formed into a sheet shape. A sheet-like adsorbent has been proposed (Patent Document 3).

JP 2006-125631 A JP 2005-83463 A JP 2006-194297 A

  By the way, in recent years, the thickness reduction and the complexity of the structure of the heat insulation box are rapidly progressing. Along with this, in the vacuum heat insulating material as described above, when a granular or powdery adsorbent such as calcium oxide is used as the adsorbent, the shape of the adsorbent is reflected on the surface of the vacuum heat insulating material, A new problem has arisen that unevenness (a large number of convex portions) is formed on the surface of the vacuum heat insulating material. If unevenness is formed on the surface of the vacuum heat insulating material, it is not preferable in that the surface smoothness is lowered.

  When the surface smoothness of a vacuum heat insulating material falls, there exists a problem that 1) a vacuum heat insulating material cannot be closely_contact | adhered to the member used as heat insulation by the said convex part, and heat insulation performance falls. In recent years, due to the thinning of the heat insulation box and the complexity of the structure, it has become difficult to ensure the adhesion between the metal plate, metal frame, refrigeration device, and the like that constitute the heat insulation box and the vacuum heat insulating material. Yes. Therefore, there is a possibility that the problem becomes more serious. In addition, 2) the entire vacuum heat insulating material cannot be uniformly pressed during pressing, and cannot be formed into a target shape (thickness). 3) A packaging bag containing a core material and an adsorbent. Can cause problems such as damage. Furthermore, rails are attached to both sides of the vegetable compartment or the like of the refrigerator, and a storage box is locked to the rails so that the storage box can be pulled out forward. In such a structure, 4) When the storage box is moved back and forth, the screw fixing the rail applies a load to the convex portion, and the packaging bag storing the core material and the adsorbent is damaged. The specific problem is also pointed out. In order to solve these problems, it is necessary to achieve a higher level of surface smoothness than before.

  In the sheet-like adsorbent described in Patent Document 3, since the soft resin fills the gaps between the granular or powdery adsorbents, unevenness due to the adsorbent is hardly formed, and the surface smoothness is relatively high. It is possible to constitute a vacuum heat insulating material. However, in the sheet-like adsorbent, since the surface of the adsorbent is covered with a soft resin, the adsorbent may not exhibit its original adsorption performance. In such a case, there is a problem that the vacuum heat insulating material deteriorates with time and cannot maintain its performance over a long period of time. Particularly in recent years, from the viewpoint of space saving, the internal structure of the heat insulation box (three-dimensional shape of the refrigerant pipe, motor, electronic control box, etc.) has become denser and more complicated, and the vacuum heat insulating material is V-shaped according to the internal structure. There is a need to bend the vacuum heat insulating material, such as bending into a mold. When a granular adsorbent is present, accurate folding is difficult, and there is a demand to reduce the arrangement area of the adsorbent. When the arrangement area of the adsorbent is reduced, there is a high possibility that the decrease in the adsorption performance of the adsorbent as described above becomes a more significant problem.

  The present invention has been made to solve the above-described problems of the prior art. In other words, the present invention makes it difficult to form irregularities due to the adsorbent, has high surface smoothness, and can fully exhibit the original adsorption performance of the adsorbent, maintaining its heat insulation performance over a long period of time. It is intended to provide a vacuum heat insulating material that can be used.

  The present inventors diligently studied the above problem. As a result, the granular adsorbent is encapsulated in the bag without being bound by a binder, and two types of core material, a hard core material and a soft core material, are used as the core material, and the soft core material is used to remove the granular adsorbent from the granular adsorbent. The present invention has been completed by conceiving that the above problem can be solved by coating the surface of the adsorbing layer. That is, according to the present invention, the following vacuum heat insulating material is provided.

  The vacuum heat insulating material of the present invention comprises a laminate having a structure in which a core material layer formed of a core material made of an inorganic fiber mat and an adsorbent layer formed of a granular adsorbent are laminated. A vacuum insulation material that is housed in a packaging bag and vacuum packaged, wherein the laminate is formed of a hard core material having an 80% compressive strength of 0.18 MPa or more. A material layer, and at least one soft core layer formed of a soft core material having an 80% compressive strength of 0.18 MPa or less and lower than the 80% compressive strength of the hard core material by 0.1 MPa or more; An adsorbent layer formed by an adsorbent pack in which the adsorbent is sealed in a bag made of a gas permeable sheet, and the soft core layer abuts against at least one surface of the adsorbent layer Arranged so that the adsorption At least one surface of the layer and having a coated structure by the soft core layer.

  In the present invention, the laminate preferably has a structure in which the hard core layer, the adsorbent layer, and the soft core layer are sequentially laminated, and the laminate includes the hard core material. As layers, a first hard core layer and a second hard core layer are provided, and the first hard core layer, the adsorbent layer, the soft core layer, and the second hard core layer are provided. More preferably, the layers have a structure in which layers are sequentially laminated.

  In the present invention, the laminate includes a first soft core layer and a second soft core layer as the soft core layer, and the first soft core layer is the adsorbent layer. The second soft core layer is disposed so as to abut on the second surface of the adsorbent layer, and the second surface of the adsorbent layer is disposed on the first surface of the adsorbent layer. It is preferable that both the surface of 1 and the second surface have a structure covered with the soft core layer.

  In the present invention, the laminate has a structure in which the hard core layer, the first soft core layer, the adsorbent layer, and the second soft core layer are sequentially stacked. Preferably, the laminate includes a first hard core layer and a second hard core layer as the hard core layer, the first hard core layer, the first hard core layer, It is further preferable that the soft core material layer, the adsorbent layer, the second soft core material layer, and the second hard core material layer have a layered structure.

In the present invention, the laminate has a ratio of the total thickness of the hard core layer and the total thickness of the soft core layer in the range of 1:10 to 5: 1; The total thickness of the core layer is 5 to 80 mm, the total thickness of the soft core layer is 100 mm or less; the total basis weight of the hard core layer is 1000 to 7000 g / m ² , and the soft The total weight of the core material layer is preferably 300 to 2500 g / m ² .

  In the present invention, the adsorbent layer is formed in a rectangular shape, and the soft core layer covers the entire surface of at least one of the adsorbent layers, and at least the adsorbent from the outer edge of the adsorbent layer. The length of the short side of the agent layer is preferably extended.

  The vacuum heat insulating material of the present invention is difficult to form irregularities due to the adsorbent, has high surface smoothness, and can fully exhibit the original adsorption performance of the adsorbent, and the heat insulation performance over a long period of time. Can be maintained.

It is a schematic end view which shows typically the cut end surface which cut | disconnected the vacuum heat insulating material which is one Embodiment of this invention in the thickness direction. It is a schematic end view which shows typically the cut end surface which cut | disconnected the vacuum heat insulating material which is another embodiment of this invention in the thickness direction. It is a schematic end view which shows typically the cut end surface which cut | disconnected the vacuum heat insulating material which is another embodiment of this invention in the thickness direction. It is a schematic end view which shows typically the cut end surface which cut | disconnected the vacuum heat insulating material which is another embodiment of this invention in the thickness direction. It is a schematic end view which shows typically the cut end surface which cut | disconnected the vacuum heat insulating material of the comparative examples 1 and 2 in the thickness direction. It is a schematic end view which shows typically the cut end surface which cut | disconnected the vacuum heat insulating material of the comparative example 3 in the thickness direction.

  Hereinafter, the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the following embodiment, and includes all objects having the invention-specific matters.

[1] Vacuum insulation material:
The vacuum heat insulating material of the present invention stores a laminated body having a structure in which a core material layer 2 and an adsorbent layer 4 are laminated, like a vacuum heat insulating material 1 shown in FIG. Wrapped.

[1-1] Core material layer:
The core material layer 2 is a layer formed of a core material made of an inorganic fiber mat. A core material is a member which bears the heat insulation of a vacuum heat insulating material. The inorganic fiber mat refers to an aggregate (web) in which inorganic fibers are laminated regardless of the thickness or density. The inorganic fiber is a fiber made of an inorganic material, and examples thereof include glass fiber, ceramic fiber, and metal fiber. Slag fiber, basalt fiber (rock wool, basalt fiber) and the like can also be used. In these, the glass fiber which is excellent in heat insulation and moldability is preferable.

  The vacuum heat insulating material of this invention is equipped with the hard core material layer 8 and the soft core material layer 10 as the core material layer 2, like the vacuum heat insulating material 1 shown in FIG. That is, it is characterized in that two or more kinds of core materials having different compressive strengths are used in combination.

[1-1A] Hard core layer:
The hard core layer is a layer formed of a hard core having an 80% compressive strength of 0.18 MPa or more.

  “80% compressive strength” means the repulsive force when the core material is compressed to 20% of the initial thickness. Specifically, it can be measured using a general-purpose tensile compression tester under test conditions of a compression speed of 1 mm / min. In the present invention, the 80% compressive strength is an index of the ease with which the core material is crushed with respect to external force. 80% is taken into consideration that the core material is compressed to about 30% of the initial thickness during vacuum packaging. That is, it is only possible to accurately evaluate the characteristics of the core material by evaluating the repulsive force in a highly compressed state.

  The 80% compressive strength of the hard core material needs to be 0.18 MPa or more, preferably 0.20 MPa or more. By setting it to 0.18 MPa or more, moderate rigidity is maintained as the whole core material layer. Therefore, it is excellent in the handling property of the core material at the time of manufacture (ease of work for storing the core material inside the packaging bag, etc.). Moreover, excessive shrinkage of the core material is prevented during vacuum packaging. This makes it difficult for the shape of the adsorbent to be reflected on the surface of the vacuum heat insulating material, thereby effectively preventing a decrease in surface smoothness. Furthermore, since a moderate space | gap is maintained in a core material, heat insulation performance does not fall easily. Although an upper limit is not specifically limited, From a viewpoint of preventing that a packaging bag is damaged at the time of vacuum packaging, it is preferable to set it as 0.70 Mpa or less.

  The vacuum heat insulating material of the present invention includes at least one hard core material layer. That is, the vacuum heat insulating material of the present invention is provided with only one hard core material layer 8 on one side of the adsorbent layer 4 like the vacuum heat insulating material 1A shown in FIG. 2 and the vacuum heat insulating material 1B shown in FIG. 1 and each of the adsorbent layers 4 includes two hard core layers 8 (that is, two layers) as in the vacuum heat insulating material 1 shown in FIG. 1 and the vacuum heat insulating material 1C shown in FIG. It may be. In the structure having only one hard core layer, since the soft core layer is located on the outermost surface of the laminate, the hard core and the packaging bag are not rubbed when the vacuum heat insulating material is bent. In addition, it is possible to prevent the occurrence of pinholes in the packaging bag. On the other hand, the structure including the two hard core layers is excellent in dimensional stability and handling property when attached to the heat insulation box.

The density of the hard core material layer is preferably 50~180kg / m ^3, and still more preferably from 60~160kg / m ^3. By setting it as 50 kg / m < ³ > or more, rigidity required as a core material is provided and it is excellent in the handling property of the core material at the time of manufacture. On the other hand, by setting it as 180 kg / m < ³ > or less, the density increase of the core material in the case of vacuum packaging and the time-dependent fall of heat insulation performance can be suppressed.

  The thickness of the hard core layer is preferably 5 mm or more, more preferably 10 mm or more, and particularly preferably 15 mm or more in a state before vacuum packaging. By setting it as 5 mm or more, an increase in core material density can be suppressed during vacuum packaging. On the other hand, in order to make the shape of the adsorbent difficult to be reflected on the surface of the vacuum heat insulating material and not reduce the surface smoothness, the thickness is preferably 80 mm or less, more preferably 60 mm or less, and 50 mm. It is particularly preferred that

  The form of the hard core material is not particularly limited as long as it has the 80% compressive strength. For example, an inorganic fiber mat formed using a conventionally known method such as a chemical bond method, a wet papermaking method, or a needle punch method can be used. Hereinafter, each method will be described.

(A) Chemical bond method:
First, an inorganic fiber web is formed by a centrifugal method. As the inorganic fiber used for forming the web, glass fiber, slag fiber, and basalt fiber (rock wool) are preferable. The fiber diameter of the inorganic fiber is preferably 2 to 7 μm, and more preferably 2 to 4 μm.

  A thermosetting binder is applied to the inorganic fiber web formed as described above, and the thermosetting binder is cured by heating to bind the inorganic fibers to form an inorganic fiber mat. The coating amount of the thermosetting binder is preferably 2 to 15% by mass and more preferably 2 to 6% by mass with respect to the mass of the inorganic fiber mat. Examples of thermosetting binders include resol type phenol resins, melamine resins, benzoguanamine resins, acetoguanamine resins, urea resins, furan resins, and other aldehyde condensable resins; esterification of polycarboxylic acids and polyols (including polysaccharides). And the like.

According to the chemical bond method, the density is 50 to 100 kg / m ³ (more specifically 60 to 90 kg / m ³ ), and the basis weight is 1200 to 4000 g / m ² (more specifically 1250 to 3000 g / m ² ). An inorganic fiber mat having a thickness of 10 to 60 mm (more specifically, 15 to 40 mm) is obtained. It is preferable to use one obtained by laminating 1 to 4 layers of the inorganic fiber mats thus obtained as the hard core material.

(B) Papermaking method (wet papermaking method):
First, an inorganic fiber web is formed by a centrifugal method or a spinning method. The kind of inorganic fiber to be used, fiber diameter, and fiber length are the same as in the chemical bond method. The inorganic fiber web is once dispersed in an excess amount of water, and then formed into a sheet by a papermaking method to obtain an inorganic fiber sheet.

  For example, using a water tank equipped with a movable mesh at the bottom, the inorganic fiber web and an excessive amount of water are put into the water tank and stirred sufficiently to disperse the inorganic fibers in the water, and then allowed to stand. For example, a method of forming the inorganic fiber sheet on the mesh by allowing the inorganic fibers to naturally settle on the mesh can be exemplified. Instead of allowing the inorganic fibers to settle naturally, after a predetermined time has passed (before spontaneous sedimentation), the mesh is forcedly pulled up to laminate the inorganic fibers on the mesh, You may employ | adopt the method of forming an inorganic fiber sheet. The basis weight of the inorganic fiber sheet can be controlled by the relationship between the area of the mesh and the amount of inorganic fibers.

  When forming an inorganic fiber sheet by a papermaking method, a binder (organic binder) for binding inorganic fibers to each other is not necessary. The binderless inorganic fiber sheet is preferable in that it does not generate a gas derived from the binder and can prevent deterioration of the vacuum heat insulating material over time.

  However, in the papermaking method, a binder may be used as in the chemical bond method. When a binder is used, there exists an advantage that the handling (handling) of the core material at the time of vacuum packaging becomes easy. Regarding the kind of the binder, a thermosetting resin may be used according to the chemical bond method, or a water-soluble or emulsion type thermoplastic resin may be used. Examples of the thermoplastic resin that can be used include polystyrene resins, acrylic resins, vinyl acetate resins, polyester resins, polyurethane resins, polyvinyl alcohol resins, and epoxy resins.

  The binding method can also be performed according to the chemical bond method. However, in the case of the papermaking method, it is possible to form a core material that is easy to handle during vacuum packaging even if the amount of the binder is small compared to the chemical bond method. The amount of the binder attached to the inorganic fiber is preferably 0.5 to 5% by mass, more preferably 0.5 to 3% by mass with respect to the mass of the inorganic fiber. When using a binder, the binder may be added to water in which inorganic fibers are dispersed. The amount of binder added to water is preferably adjusted as appropriate according to the amount of adhesion to inorganic fibers.

  After the inorganic fiber sheet is formed on the mesh, it is allowed to stand at room temperature for natural drying, or the inorganic fiber sheet is peeled off from the mesh and heated (forced drying) to remove moisture adhering to the inorganic fiber. . Thereby, the inorganic fiber sheet used as a core material can be obtained. When a binder is used, inorganic fibers are bonded to each other during natural drying or forced drying. For forced drying, a far-infrared oven or a hot air generating oven is preferably used to heat to 100 ° C. or higher, and when a thermosetting binder is used, it is preferably heated to 150 ° C. or higher.

According to the papermaking method, the basis weight is 120 to 200 g / m ² (more specifically 140 to 180 g / m ² ) and the thickness is 0.1 to 2 mm (more specifically 0.5 to 2 mm). A fiber sheet is obtained. It is preferable that 15 to 30 layers of the inorganic fiber sheet thus obtained are laminated to form an inorganic fiber mat and used as a hard core material.

(C) Needle punch method-1:
First, inorganic fibers are formed by a spinning method. As a material for the inorganic fiber, glass having a low alkali metal oxide content such as E glass, AR glass, S glass, basalt, etc. can be used. These materials are melted and fiberized in a spinning furnace to form inorganic fibers. The fiber diameter is preferably 4 to 13 μm, and more preferably 4 to 9 μm. When the thickness is 4 μm or more, the fibers are hardly cut during spinning, and the productivity is improved. The heat insulation as a vacuum heat insulating material can be improved by setting it as 13 micrometers or less.

  Next, the inorganic fibers are bundled with water; an organic binder such as starch, polyurethane resin, acrylic resin, or the like to form a fiber bundle, and the fiber bundle is chopped into a long fiber bundle having a fiber length of 25 to 100 mm. The inorganic fiber may be chopped and dried immediately after forming the fiber bundle, or after being formed into a fiber bundle, once wound into a roll shape, dried in a roll shape, and chopped the fiber bundle drawn from the roll Good.

  Further, the long fiber bundle is carded (opened) and formed into a mat shape, and then needle punching is performed to form an inorganic fiber mat. Carding can be performed by a carding device, and needle punching can be performed by a needle punch machine. As the needle punch machine, a needle having a needle portion of 3000 to 5000 needles / liner · m is used, and the needle depth is 10 times or more in the flow direction of the inorganic fiber mat and the needle depth is 10 mm or more. Punching is preferable. The density of the inorganic fiber mat can be controlled by the number of needle punches per unit area.

According to the needle punch method-1, the density is 80 to 150 kg / m ³ (more specifically 90 to 120 kg / m ³ ), and the basis weight is 400 to 1500 g / m ² (more specifically 600 to 1200 g / m). ² ) An inorganic fiber mat having a thickness of 5 to 20 mm (more specifically, 6 to 15 mm) is obtained. It is preferable to use a laminate obtained by laminating 2 to 6 layers of inorganic fiber mats thus obtained as the hard core material.

(D) Needle punch method-2:
First, an inorganic fiber web is formed by a centrifugal method. A glass (soda lime glass) etc. can be used as a material of an inorganic fiber. The material is melted and an inorganic fiber web having a fiber diameter of ^{3 to} 7 μm and a density of 16 to 32 kg / m ³ is formed by a centrifugal method. An inorganic fiber mat is obtained by further needle punching the inorganic fiber web. The method and conditions for needle punching can be performed according to needle punching method-1.

According to the needle punch method-2, the density is 50 to 150 kg / m ³ (more specifically 60 to 120 kg / m ³ ), and the basis weight is 300 to 1500 g / m ² (more specifically 400 to 1200 g / m). ² ) An inorganic fiber mat having a thickness of 5 to 30 mm (more specifically, 5 to 20 mm) is obtained. Since the inorganic fiber produced by the centrifugal method is crimped, the density of the inorganic fiber mat formed by the needle punch method-2 tends to be lower than that of the inorganic fiber mat formed by the needle punch method-1. It is preferable to use a laminate obtained by laminating 2 to 6 layers of inorganic fiber mats thus obtained as the hard core material.

[1-1B] Soft core layer:
The soft core layer is a layer formed of a soft core material having an 80% compressive strength of 0.18 MPa or less and lower than the 80% compressive strength of the hard core material by 0.1 MPa or more.

  The 80% compressive strength of the soft core material needs to be 0.18 MPa or less, preferably 0.05 to 0.18 MPa, and more preferably 0.09 to 0.16 MPa. The 80% compressive strength of the soft core material needs to be 0.1 MPa or more lower than the 80% compressive strength of the hard core material, and is preferably 0.1 to 0.5 MPa lower. By setting the 80% compressive strength of the soft core material to 0.18 MPa or less and lower than the 80% compressive strength of the hard core material by 0.1 MPa or more, the compressive force applied during vacuum packaging is dispersed and buffered. Therefore, it becomes difficult for the shape of the adsorbent to be reflected on the surface of the vacuum heat insulating material, and a decrease in surface smoothness can be effectively prevented. Moreover, the space | gap in a core material reduces by vacuum packaging, and the loading efficiency of a vacuum heat insulating material improves. The lower limit of the 80% compressive strength of the soft core material is not particularly limited, but it is preferably 0.05 MPa or more and 0.09 MPa or more from the viewpoint of maintaining the handling property during vacuum packaging without excessively reducing the rigidity. More preferably.

The density of the soft core material before vacuum packaging is preferably 48 kg / m ³ or less, more preferably 32 kg / m ³ or less, and particularly preferably 30 kg / m ³ or less. By setting the density to 48 kg / m ³ or less, the inorganic fibers constituting the soft core material are sparsely arranged (that is, the interval between the inorganic fibers is widened), and inorganic when a compressive load is applied during vacuum packaging. The moving distance of the fiber increases. That is, it is possible to improve the dispersion / buffering effect of the compressive force of the soft core material. On the other hand, the density is preferably 16 kg / m ³ or more. By setting the density to 16 kg / m ³ or more, the soft core material is not excessively bulky, and the core material can be handled at the time of manufacture.

  The thickness of the soft core material is preferably 100 mm or less, and more preferably 75 mm or less in a state before vacuum packaging. By setting the thickness to 100 mm or less, a dispersion / buffering effect of compressive force occurs, and the shape of the adsorbent is hardly reflected on the surface of the vacuum heat insulating material. That is, the surface smoothness is improved. The lower limit of the thickness is not particularly limited, but from the viewpoint of reliably exhibiting the above-described dispersion / buffering effect of the compressive force, the thickness is preferably about the same as the adsorbent, for example, 10 mm or more, and 20 mm or more. Further preferred.

  The vacuum heat insulating material of the present invention includes at least one soft core material layer. That is, the vacuum heat insulating material of the present invention is provided with only one soft core material layer 10 on one side of the adsorbent layer 4 like the vacuum heat insulating material 1B shown in FIG. 3 and the vacuum heat insulating material 1C shown in FIG. 1 and each of the adsorbent layers 4 is provided with one soft core material layer 10 (that is, two layers) like the vacuum heat insulating material 1 shown in FIG. 1 and the vacuum heat insulating material 1A shown in FIG. It may be.

  As long as it has the 80% compressive strength, the form of the soft core is not particularly limited. However, the following forms can be mentioned. None of these forms use a binder. By preventing the fibers from being fixed by the binder, an inorganic fiber mat can be formed in which the fibers form a mat immediately after molding, but the fibers behave freely and can be easily deformed by external pressure. As a result, the stress gradient (load gradient) generated between the hard adsorbent and the easily deformable soft core is reduced with respect to the load applied from the outside in the compression process during vacuum packaging. It is possible to disperse and relax using the deviation of the gap and to smoothly guide the surface of the vacuum heat insulating material.

(A) Centrifugal method:
An inorganic fiber web is formed by a centrifugal method, and this is used as it is as an inorganic fiber mat. As the inorganic fiber to be used, glass fiber is preferable. The fiber diameter of the inorganic fiber is preferably 2 to 7 μm, and more preferably 2 to 4 μm.

According to the centrifugal method, the density is 10 to 24 kg / m ³ (more specifically 14 to 20 kg / m ³ ), the basis weight is 100 to 1200 g / m ² (more specifically 500 to 1000 g / m ² ), An inorganic fiber mat having a thickness of 10 to 50 mm (more specifically, 20 to 40 mm) is obtained. What laminated | stacked 1-4 layers of the inorganic fiber mat obtained in this way is preferable as a soft core material.

(B) Needle punch method-3:
The inorganic fiber mat formed in (a) is further subjected to needle punching to obtain an inorganic fiber mat. The needle punch is preferably performed using a needle part with a needle number of 1000 to 3000 needles / liner · m, with a needle depth of about 1 mm / cm and a needle depth of 10 mm or more in the flow direction of the inorganic fiber mat. The density of the inorganic fiber mat can be controlled by the number of needle punches per unit area.

According to the needle punch method-3, the density is 50 kg / m ³ or less (more specifically ³⁰ to 50 kg / m ³ ), and the basis weight is 100 to 500 g / m ² (more specifically 100 to 400 g / m ^2). ), An inorganic fiber mat having a thickness of 5 to 30 mm (more specifically, 5 to 20 mm) is obtained. It is preferable to use one obtained by laminating one or two layers of the inorganic fiber mat thus obtained as the soft core material.

(C) Other:
For example, you may use as a soft core material what filled the air-permeable nonwoven fabric bag body with the inorganic fiber web which has not provided the binder.

[1-2] Adsorbent layer:
The adsorbent layer is a layer formed of a granular adsorbent. The vacuum heat insulating material of the present invention includes an adsorbent layer formed by an adsorbent pack in which the adsorbent is sealed in a bag made of a gas permeable sheet. By enclosing the granular adsorbent in the bag, handling such as loading of the adsorbent becomes easy.

Examples of the type of adsorbent include calcium oxide having a particle diameter of 1 to 10 mm, silica gel, zeolite, and the like. Examples of the gas permeable sheet include a nonwoven fabric made of plastic fibers, Japanese paper, and the like. What is necessary is just to set the area and maximum thickness of an adsorbent layer suitably according to the size of a vacuum heat insulating material. For example, it is preferable to use one having an area of 16 to 100 cm ² and a maximum thickness of 5 to 20 mm.

[1-3] Laminate:
A laminated body has the structure where the core material layer 2 and the adsorbent layer 4 were laminated | stacked like the vacuum heat insulating material 1 shown in FIG. The soft core material layer 10 is arranged so as to abut against at least one surface of the adsorbent layer 4, and at least one surface of the adsorbent layer 4 is covered with the soft core material layer 10. By disposing the soft core layer 10 in contact with the adsorbent layer 4, it is possible to obtain a compressive force dispersion / buffer effect. The laminated structure of the laminated body is not particularly limited as long as the above requirements are satisfied. For example, the laminated structure can be as follows.

[1-3A] First laminated structure:
The laminated body preferably has a structure in which a hard core layer 8, an adsorbent layer 4, and a soft core layer 10 are sequentially stacked as in a vacuum heat insulating material 1B shown in FIG. In such a structure, since the soft core layer is located on the outermost layer of the laminate, when the vacuum heat insulating material is folded, the hard core and the packaging bag are not rubbed, and a pinhole is generated in the packaging bag. Can be prevented.

  However, the said laminated body is equipped with the 1st hard core material layer 8a and the 2nd hard core material layer 8b as the hard core material layer 8, like the vacuum heat insulating material 1C shown in FIG. The hard core material layer 8a, the adsorbent layer 4, the soft core material layer 10 and the second hard core material layer 8b may be sequentially laminated. Since this structure has high hardness on both sides of the formed vacuum heat insulating material, it is preferable in terms of excellent dimensional stability and handling properties when attached to a heat insulating box.

[1-3B] Second laminated structure:
The laminated body includes a first soft core layer 10a and a second soft core layer as the soft core layer 10 as in the vacuum heat insulating material 1 shown in FIG. 1 and the vacuum heat insulating material 1A shown in FIG. 10b, the first soft core material layer 10a is disposed so as to abut against the first surface of the adsorbent layer 4, and the second soft core material layer 10b is the second soft core material layer 10b. It is preferable that the first surface and the second surface of the adsorbent layer 4 are arranged so as to be in contact with the surface and have a structure in which both are covered with the soft core material layer 10.

  According to the said structure, both surfaces of an adsorbent layer are coat | covered with the soft core material layer, and it is preferable in the point whose surface smoothness of the formed vacuum heat insulating material is higher. In the above structure, the first soft core material layer 10a and the second soft core material layer 10b may be configured as separate bodies or may be configured as a single body. That is, a structure may be adopted in which one soft core is folded and the adsorbent layer is wrapped inside the folded portion.

  In the laminate, a hard core layer 8, a first soft core layer 10a, an adsorbent layer 4, and a second soft core layer 10b are sequentially stacked as in the vacuum heat insulating material 1A shown in FIG. It is preferable to have a structure. In addition to the higher surface smoothness of the formed vacuum heat insulating material, this structure is similar to the vacuum heat insulating material 1B shown in FIG. 3, and when the vacuum heat insulating material is bent, the hard core material and the packaging bag This prevents the pinhole from occurring on the packaging bag without being rubbed.

  Moreover, the said laminated body is equipped with the 1st hard core material layer 8a and the 2nd hard core material layer 8b as the hard core material layer 8, like the vacuum heat insulating material 1 shown in FIG. The hard core material layer 8a, the first soft core material layer 10a, the adsorbent layer 4, the second soft core material layer 10b, and the second hard core material layer 8b are sequentially laminated. Is preferred. This structure has high surface smoothness of the formed vacuum heat insulating material, and in addition to being able to improve surface smoothness even in a vacuum heat insulating material that is required to be thin, in addition to the vacuum heat insulating material 1C shown in FIG. It is preferable in terms of excellent dimensional stability and handling properties when attached to a heat insulating box.

[1-3C] Total thickness of hard core layer and soft core layer:
The laminate preferably has a ratio of the total thickness of the hard core layer and the total thickness of the soft core layer in the range of 1:10 to 5: 1. Is more preferably within the range of: 1. By making the total thickness of the hard core layer 0.1 times or more than the total thickness of the soft core layer, the ratio of the bulky soft core layer is kept to a certain limit, and the handling properties of the core material during manufacturing Can be improved. On the contrary, by making the total thickness of the hard core layer 5 times or less with respect to the total thickness of the soft core layer, the effect of dispersing and buffering the compressive force of the soft core is sufficiently exhibited, and the present invention The effect of improving the surface smoothness, which is the main effect of the above, can be obtained. The “total thickness” is the thickness of all hard core layers (or soft core layers) when the hard core layer (or soft core layer) is composed of a plurality of layers. Means the total value.

  The total thickness of the hard core layer is preferably 5 to 80 mm, and more preferably 10 to 60 mm. By setting it as 5 mm or more, the thickness of the shape | molded vacuum heat insulating material can be ensured and desired heat insulation performance can be obtained. On the other hand, by setting the thickness to 80 mm or less, it is possible to shorten the extra length (clearance) of the packaging bag formed in advance in consideration of workability during vacuum packaging. Thereby, in the shape | molded vacuum heat insulating material, the thermal bridge | crosslinking in the extra length part of a packaging bag can be suppressed.

  The total thickness of the soft core layer is preferably 100 mm or less, and more preferably 75 mm or less. By setting it as 100 mm or less, the thickness of the bulky soft core material can be kept at a certain limit, and the handling property of the core material at the time of manufacture can be improved. The lower limit is not particularly limited, but in order to sufficiently exhibit the compressive force dispersion / buffering effect of the soft core material and to exhibit the effect of improving the surface smoothness, which is the main effect of the present invention, the lower limit is set to 10 mm or more. It is preferable that the thickness is 20 mm or more.

[1-3D] Total basis weight of hard core layer and soft core layer:
The total basis weight of the hard core layer is preferably 1000~7000g / m ^2, more preferably from 1500~5000g / m ^2, and particularly preferably 2500~4500g / m ^2. By setting it as 1000 g / m < ² > or more, rigidity required as a core material is provided and it is excellent in the handleability at the time of attachment to a heat insulation box. On the other hand, by setting it as 7000 g / m < ² > or less, the density rise of the core material in the case of vacuum packaging and the time-dependent fall of heat insulation performance can be suppressed. “Total basis weight” is the sum of the masses of all hard core layers (or soft core layers) when the hard core layer (or soft core layer) is composed of a plurality of layers. It means a value obtained by dividing the value by the area of the laminate.

The total basis weight of the soft core layer is preferably 300~2500g / m ^2, more preferably from 500 to 2000 g / m ^2, and particularly preferably 500~1800g / m ^2. By setting it to 300 g / m ² or more, it is possible to exhibit the effect of dispersing and buffering the compressive force of the soft core material and to improve the surface smoothness. On the other hand, by setting it as 2500 g / m < ² > or less, a soft core material does not become excessively heavy, and the handling property of the core material at the time of manufacture can be improved.

[1-3E] Arrangement of adsorbent layer:
When the adsorbent layer is formed in a rectangular shape, the soft core layer covers the entire surface of at least one of the adsorbent layers, and at least the adsorbent layer from the outer edge of the adsorbent layer. It is preferable to extend by the length of the short side. For example, when the adsorbent layer is formed in a rectangular shape having a long side of 10 cm and a short side of 7 cm, the soft core layer may extend from the outer edge (four sides) of the adsorbent layer by at least 7 cm in width. preferable. By adopting such a structure, the adsorbent layer is surely covered with the soft core layer, and the effect of dispersing and buffering the compressive force of the soft core is sufficiently exhibited, which is the main effect of the present invention. The effect of improving the surface smoothness can be exhibited.

[1-4] Packaging bag:
The packaging bag is a gas barrier packaging bag. For example, a multilayer film having a structure in which a metal foil and a plastic film are laminated; a multilayer film having a structure in which a metal vapor-deposited film and a plastic film are laminated; The thickness of the packaging bag is preferably 40 to 200 μm, and more preferably 80 to 150 μm.

[1-5] Vacuum packaging:
The vacuum heat insulating material of the present invention is obtained by housing the laminate in a gas barrier packaging bag and vacuum packaging it. As a method of vacuum packaging, for example, after the laminate is housed in the packaging bag, it is evacuated, the degree of vacuum inside the packaging bag is 0.1 to 10 Pa, and the opening of the packaging bag is heat sealed; Can be mentioned.

In the vacuum heat insulating material of the present invention, the density of the entire core layer after vacuum packaging is preferably 300 kg / m ³ or less, more preferably 260 kg / m ³ or less. By setting it as 300 kg / m < ³ > or less, the high heat insulation performance of the shape | molded vacuum heat insulating material can be exhibited. The lower limit is not particularly limited, but it is preferably 150 kg / m ³ or more, and preferably 220 kg / m ³ or more from the viewpoint of imparting rigidity necessary as a core material and improving handling properties when attached to a heat insulating box. More preferably.

  Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples. However, the present invention is not limited to the configurations of the following examples.

Example 1
A vacuum heat insulating material having the same structure as the vacuum heat insulating material 1 shown in FIG. 4 was produced. The hard core layer 8 was formed of an inorganic fiber mat (hard core material) produced by a chemical bond method. The hard core material was prepared by applying a resole-type phenol resin binder to a glass wool mat having a density of 75 kg / m ³ and a thickness of 30 mm so as to be 4% by mass of the total weight, followed by thermosetting. The basis weight of the hard core material was 2250 g / m ² , and the 80% compressive strength was 0.25 MPa.

The soft core material layer 10 was formed of an inorganic fiber mat (soft core material) produced by a centrifugal method. The soft core material is a glass wool mat having a fiber diameter of 7 μm, a density of 16 kg / m ³ , and a thickness of 20 mm. This glass wool mat is not provided with a binder. The soft core material had a basis weight of 320 g / m ² and an 80% compressive strength of 0.09 MPa.

The adsorbent layer 4 was formed by an adsorbent pack in which granular calcium oxide (particle diameter: 1 to 3 mm) was enclosed in a non-woven bag made of polyolefin fibers. The adsorbent pack had an area of 70 cm ² and a maximum thickness of 12 mm.

A laminate obtained by laminating the adsorbent pack and one piece of the soft core material was sandwiched between the two hard core materials. The total thickness of the laminate hard core layer of 60 mm, the total basis weight is 4500 g / m ^2, the total thickness of the soft core layer of the laminate is 20 mm, the total basis weight was 320 g / m ² .

The laminate was housed in a gas barrier packaging bag and vacuum-packed to obtain a vacuum heat insulating material having a 550 mm square, an average thickness of 20 mm, and a density of 240 kg / m ³ . As the gas barrier packaging bag, a packaging bag made of a multilayer film having a structure in which a high-density polyethylene film, an aluminum foil, a PET film, and a nylon film were sequentially laminated from the inside was used.

(Example 2)
A vacuum heat insulating material having the same structure as the vacuum heat insulating material 1A shown in FIG. 2 was manufactured. A vacuum heat insulating material was manufactured in the same manner as in Example 1 except for the following conditions.

The hard core material layer 8 was formed of an inorganic fiber mat (hard core material) produced by the needle punch method-1 described above. First, E glass fibers having a fiber diameter of 6 μm were formed by a spinning method, the E glass fibers were converged into a fiber bundle, and the fiber bundle was chopped into a long fiber bundle having a fiber length of 35 mm. The long fiber bundle was opened with a carding machine and formed into a mat shape. Thereafter, needle punching with a needle density of 5000 needles / liner · m is performed with a needle punch of 2 times / cm and a needle depth of 10 mm or more with respect to the flow direction of the inorganic fiber mat, and consists of long glass fibers. An inorganic fiber mat having a thickness of 10 mm and a basis weight of 1000 g / m ² was formed. A laminate obtained by laminating three layers of the inorganic fiber mat was used as the hard core material. The hard core material had an 80% compressive strength of 0.54 MPa, a density of 100 kg / m ³ , a thickness of 30 mm, and a basis weight of 3000 g / m ² .

The soft core material layer 10 was formed of an inorganic fiber mat (soft core material) produced by a centrifugal method. The soft core material is a glass wool mat having a fiber diameter of 4 μm, a density of 16 kg / m ³ , and a thickness of 25 mm. This glass wool mat is not provided with a binder. The soft core material had a basis weight of 400 g / m ² and an 80% compressive strength of 0.09 MPa.

As the adsorbent layer 4, four adsorbent packs (area 70 cm ² , maximum thickness 12 mm) used in Example 1 were connected. That is, the total area of the adsorbent pack was 280 cm ² .

The adsorbent pack was wrapped from above and below with one sheet of the soft core material, and placed on one sheet of the hard core material to obtain a laminate. The total thickness of the hard core layer of the laminate was 30 mm and the total basis weight was 3000 g / m ^2. The total thickness of the soft core layer of the laminate was 50 mm and the total basis weight was 800 g / m ² . .

The laminate was housed in a gas barrier packaging bag and vacuum packaged to obtain a vacuum heat insulating material having a 550 mm square, an average thickness of 15 mm, and a density of 260 kg / m ³ .

Example 3
A vacuum heat insulating material having the same structure as the vacuum heat insulating material 1 shown in FIG. 1 was produced. A vacuum heat insulating material was manufactured in the same manner as in Example 1 except for the following conditions.

The hard core layer 8 was formed of an inorganic fiber mat (hard core material) produced by the needle punch method-2 described above. First, an inorganic fiber web made of glass wool having a fiber diameter of 4 μm was formed by a centrifugal method. A needle punch machine having a needle density of 5000 needles / liner-m needles is used to punch the inorganic fiber web at a needle depth of 30 mm at a rate of 2 times / cm in the flow direction of the inorganic fiber web. / M ³ , a thickness of 20 mm, and an inorganic fiber mat having a basis weight of 1200 g / m ² was formed. The hard core had an 80% compressive strength of 0.37 MPa, a density of 60 kg / m ³ , a thickness of 20 mm, and a basis weight of 1200 g / m ² .

The soft core layer 10 was formed of an inorganic fiber mat (soft core material) produced by the needle punch method-3. First, a glass wool mat having a fiber diameter of 4 μm, a density of 16 kg / m ³ , and a thickness of 50 mm was formed by a centrifugal method. The glass wool mat is not provided with a binder. A needle punch machine having a needle density of 3000 needles / liner-m needles is used to punch the glass wool mat at a needle depth of 30 mm at a rate of once / cm in the flow direction of the inorganic fiber web. An inorganic fiber mat with m ³ , thickness 25 mm, and basis weight 800 g / m ² was formed. What laminated | stacked two layers of the said inorganic fiber mat was made into the said soft core material. The soft core material had an 80% compressive strength of 0.16 MPa, a density of 30 kg / m ³ , a thickness of 50 mm, and a basis weight of 1600 g / m ² .

As the adsorbent pack for forming the adsorbent layer 4, the adsorbent pack (area 280 cm ² , maximum thickness 12 mm) used in Example 2 was used. The adsorbent pack was put between the soft core materials and sandwiched between the two hard core materials to obtain a laminate. The total thickness of the hard core layer of the laminate was 40 mm and the total basis weight was 2400 g / m ^2. The total thickness of the soft core layer of the laminate was 50 mm and the total basis weight was 1600 g / m ² . . The laminate was stored in a gas barrier packaging bag and vacuum-packed to obtain a vacuum heat insulating material having a 550 mm square, an average thickness of 20 mm, and a density of 200 kg / m ³ .

Example 4
A vacuum heat insulating material having the same structure as the vacuum heat insulating material 1C shown in FIG. 4 was produced. A vacuum heat insulating material was manufactured in the same manner as in Example 1 except for the following conditions.

The hard core layer 8 was formed of an inorganic fiber mat (hard core material) produced by a papermaking method. First, a glass wool web made of glass fibers having a fiber diameter of 4 μm was formed by a spinning method. The glass wool web was dispersed in a large amount of water in a water tank equipped with a water-permeable nonwoven fabric filter and then made into a glass fiber sheet having a density of 160 g / m ³ , a thickness of 1 mm, and a basis weight of 160 g / m ² . What laminated | stacked the said glass fiber sheet 5 layers was made into the said hard core material. This hard core had an 80% compressive strength of 0.64 MPa, a thickness of 5 mm, and a basis weight of 800 g / m ² .

The soft core layer 10 was formed of an inorganic fiber mat (soft core material) manufactured in the same manner as in Example 3. And what laminated | stacked the said inorganic fiber mat 3 layers was made into the said soft core material. The soft core material had an 80% compressive strength of 0.16 MPa, a density of 32 kg / m ³ , a thickness of 75 mm, and a basis weight of 2400 g / m ² .

As the adsorbent pack for forming the adsorbent layer 4, the adsorbent pack (area 280 cm ² , maximum thickness 12 mm) used in Example 2 was used. A laminate obtained by laminating the adsorbent pack and one piece of the soft core material was sandwiched between the two hard core materials. The total thickness of the hard core layer of the laminate is 10 mm, the density is 160 kg / m ³ , the total basis weight is 1600 g / m ² , the total thickness of the soft core layer of the laminate is 75 mm, and the density is 32 kg. / M ³ , and the total basis weight was 2400 g / m ² . The laminate was stored in a gas barrier packaging bag and vacuum-packed to obtain a vacuum heat insulating material having a 550 mm square, an average thickness of 20 mm, and a density of 200 kg / m ³ .

(Example 5)
A vacuum heat insulating material having the same structure as the vacuum heat insulating material 1C shown in FIG. 4 was produced. A vacuum heat insulating material was manufactured in the same manner as in Example 1 except for the following conditions.

The hard core material layer 8 was formed of an inorganic fiber mat (hard core material) produced by the needle punch method-1 described above. The hard core material was formed by laminating three layers of inorganic fiber mats having a thickness of 10 mm and a weight per unit area of 1000 g / m ² , which were formed by the same method as in Example 2. The hard core material had an 80% compressive strength of 0.54 MPa, a density of 100 kg / m ³ , a thickness of 30 mm, and a basis weight of 3000 g / m ² .

The soft core material layer 10 was formed of an inorganic fiber mat (soft core material) produced by a centrifugal method. The soft core material is a glass wool mat having a fiber diameter of 4 μm, a density of 16 kg / m ³ , and a thickness of 25 mm. This glass wool mat is not provided with a binder. The soft core material had a basis weight of 400 g / m ² and an 80% compressive strength of 0.09 MPa.

As the adsorbent layer 4, four adsorbent packs (area 70 cm ² , maximum thickness 12 mm) used in Example 1 were connected. That is, the total area of the adsorbent pack was 280 cm ² .

A laminate obtained by laminating the adsorbent pack and one piece of the soft core material was sandwiched between the two hard core materials. The total thickness of the laminate hard core layer of 60 mm, the total basis weight is 6000 g / m ^2, the total thickness of the soft core layer of the laminate is 25 mm, the total basis weight was 400 g / m ² .

The laminate was housed in a gas barrier packaging bag and vacuum packaged to obtain a vacuum heat insulating material having a 550 mm square, an average thickness of 30 mm, and a density of 220 kg / m ³ .

(Comparative Example 1)
A vacuum heat insulating material having the same structure as the vacuum heat insulating material 100A shown in FIG. 5 was manufactured. A vacuum heat insulating material was manufactured in the same manner as in Example 1 except that the soft core material was not used and the adsorbent pack was sandwiched between two hard core materials. The obtained vacuum heat insulating material had a 550 mm square, an average thickness of 22 mm, and a density of 225 kg / m ³ .

(Comparative Example 2)
A vacuum heat insulating material having the same structure as the vacuum heat insulating material 100A shown in FIG. 5 was manufactured. A vacuum heat insulating material was manufactured in the same manner as in Example 3 except that the soft core material was not used and the adsorbent pack was sandwiched between two hard core materials. The obtained vacuum heat insulating material had a 550 mm square, an average thickness of 14 mm, and a density of 200 kg / m ³ .

(Comparative Example 3)
A vacuum heat insulating material having the same structure as the vacuum heat insulating material 100B shown in FIG. 6 was manufactured. A vacuum heat insulating material was manufactured in the same manner as Comparative Example 2 except that no adsorbent pack was used. The obtained vacuum heat insulating material had a 550 mm square, an average thickness of 12 mm, and a density of 200 kg / m ³ .

[Evaluation method]
About the vacuum heat insulating material of the Example and the comparative example, the performance was evaluated by surface smoothness and thermal conductivity. Hereinafter, methods for evaluating surface smoothness and thermal conductivity will be described.

(Surface smoothness)
It was evaluated whether or not the shape of the particulate adsorbent was reflected on the surface shape of the vacuum heat insulating material. The difference between the maximum thickness and the minimum thickness of the vacuum insulation was measured with a dial gauge. The case where the thickness difference between the maximum thickness and the minimum thickness exceeds 3.0 mm is “defect (×)”, the case where it is 3.0 mm or less is “good (◯)”, and the case where it is 2.0 mm or less is “particularly good (◎)” ".

(Thermal conductivity)
The heat insulating performance of the vacuum heat insulating material was evaluated based on the thermal conductivity. Moreover, it was evaluated whether the heat insulation performance deteriorated with time. First, the thermal conductivity of the vacuum heat insulating material immediately after manufacture was measured at an average temperature of 20 ° C., an upper surface of 30 ° C., and a lower surface of 10 ° C. (in the table, described as “thermal conductivity A”). Furthermore, after aging at 40 ° C. for 2 weeks, the thermal conductivity was measured again (denoted as “thermal conductivity B” in the table). The thermal conductivity was measured by a heat flow meter method according to JIS-A1412-2. As a measuring instrument, a thermal conductivity measuring device (trade name “HC-074-600”, manufactured by Eihiro Seiki Co., Ltd.) was used. The case where the difference between the thermal conductivity B and the thermal conductivity A exceeds 0.0015 W / mK is “defect (×)”, the case where it is 0.0015 W / mK or less is “good” (◯), 0.0010 W / mK or less In the case of, it was evaluated as “particularly good (（)”.

[Evaluation results]
Table 1 shows the configuration of the vacuum heat insulating material, and Table 2 shows the evaluation results. As shown in Table 2, the vacuum heat insulating materials of Examples 1 to 5 had a thickness difference of 3 mm or less, and were excellent in surface smoothness. Further, since the difference between the thermal conductivity B and the thermal conductivity A was within 0.0015 W / mK, it was recognized that the vacuum heat insulating material hardly deteriorated with time and the adsorbent was functioning effectively. Especially, the vacuum heat insulating material of Example 3 was settled in the thickness difference of the level equivalent to the vacuum heat insulating material of the comparative example 3 which does not use adsorption agent, and the surface smoothness was especially excellent.

  On the other hand, the vacuum heat insulating materials of Comparative Examples 1 and 2 had a thickness difference exceeding 3 mm, and the surface smoothness was not sufficient. Further, in the vacuum heat insulating material of Comparative Example 3, the difference between the thermal conductivity B and the thermal conductivity A exceeded 0.0015 W / mK, and deterioration with time was recognized.

1, 1A, 1B, 1C: vacuum heat insulating material, 2: core material layer, 4: adsorbent layer, 6: packaging bag, 8: hard core material layer, 8a: first hard core material layer, 8b: second 10: soft core material layer, 10a: first soft core material layer, 10b: second soft core material layer, 100A, 100B: vacuum heat insulating material.

Claims (10)

A laminated body having a structure in which a core material layer formed of a core material made of an inorganic fiber mat and an adsorbent layer formed of a granular adsorbent are stacked is housed inside a gas barrier packaging bag. A vacuum insulation material formed by vacuum packaging,
The laminate is formed of a hard core material having an 80% compressive strength of 0.18 MPa or more, at least one hard core layer, an 80% compressive strength of 0.18 MPa or less, and the hard core material Formed by a soft core material that is 0.1 MPa or more lower than the 80% compressive strength of the material, and an adsorbent pack in which the adsorbent is enclosed in a bag made of a gas permeable sheet. The adsorbent layer is disposed so that the soft core layer is in contact with at least one surface of the adsorbent layer, and at least one surface of the adsorbent layer is formed by the soft core layer. A vacuum heat insulating material characterized by having a coated structure.   The vacuum heat insulating material according to claim 1, wherein the laminate has a structure in which the hard core layer, the adsorbent layer, and the soft core layer are sequentially stacked.   The laminate includes a first hard core layer and a second hard core layer as the hard core layer, the first hard core layer, the adsorbent layer, and the soft core material. The vacuum heat insulating material according to claim 2, having a structure in which a layer and the second hard core material layer are sequentially laminated.   The laminate includes, as the soft core layer, a first soft core layer and a second soft core layer, and the first soft core layer is a first surface of the adsorbent layer. Disposed so as to abut against the second surface of the adsorbent layer, the first surface of the adsorbent layer, and the second surface of the adsorbent layer. The vacuum heat insulating material according to claim 1, wherein each of the second surfaces has a structure covered with the soft core material layer.   5. The laminate according to claim 4, wherein the laminate has a structure in which the hard core layer, the first soft core layer, the adsorbent layer, and the second soft core layer are sequentially stacked. Vacuum insulation.   The laminate includes, as the hard core layer, a first hard core layer and a second hard core layer, the first hard core layer, the first soft core layer, The vacuum heat insulating material according to claim 5, having a structure in which the adsorbent layer, the second soft core layer, and the second hard core layer are sequentially laminated.   The laminated body according to any one of claims 1 to 6, wherein a ratio of a total thickness of the hard core layer and a total thickness of the soft core layer is in a range of 1:10 to 5: 1. The vacuum heat insulating material according to item.   The vacuum heat insulating material according to claim 7, wherein the total thickness of the hard core layer is 5 to 80 mm, and the total thickness of the soft core layer is 100 mm or less. The total basis weight of the hard core material layer is 1000~7000g / m ^2, the vacuum heat insulating material according to claim 7 or 8 total basis weight of the soft core layer is 300~2500g / m ^2. The adsorbent layer is formed in a rectangular shape,
The soft core layer covers the entire surface of at least one of the adsorbent layers and extends from the outer edge of the adsorbent layer by at least the length of the short side of the adsorbent layer. The vacuum heat insulating material of any one of -9.

Images