JP2006125631A - Vacuum insulation material and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vacuum insulation material having heat insulation property and surface smoothness in a small number of processes at a low cost. <P>SOLUTION: In this vacuum insulation material, a core material formed by stacking glass fibers is sheathed by a casing bag, and the interior of the casing bag is decompressed. A sheet-like material having a surface density of 20 to 400g/m<SP>2</SP>is inserted between at least one of both surfaces of the core material and the casing bag. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a vacuum heat insulating material excellent in surface smoothness and heat insulating properties and a method for producing the same.

  Conventionally, various heat insulating materials have been used for refrigerators, low temperature containers, residential building materials, etc., and as a heat insulating material particularly excellent in heat insulating performance, a heat insulating core material is enclosed in a jacket bag, and the inside A vacuum heat insulating material having an evacuated structure is used. When these foams are housed in a bag such as an aluminum foil laminate film and the inside of the bag is evacuated, the uneven shape of the foam appears on the surface of the bag that is in close contact with the foam. The surface smoothness is inferior. The vacuum insulation material with poor surface smoothness, for example, is embedded in the wall surface of an electric refrigerator, and when urethane resin is further poured around the vacuum insulation material and foamed, the flow of the urethane resin deteriorates, A problem arises in that voids and gaps are formed on the surface and the performance is degraded. Further, even when the vacuum heat insulating material is bonded to another member, there is a problem that a gap or a gap is likely to be generated on the bonding surface, which is disclosed in Patent Document 1 in order to solve the problem. Methods are known.

Further, in Patent Document 2, a core material made of glass fiber is filled and degassed in an inner bag made of a resin film and sealed in a jacket bag for a vacuum heat insulating material, thereby providing a vacuum with excellent surface smoothness. A technique for making a heat insulating material is disclosed.
JP 2000-283385 A JP-A-4-337195

  As described in Patent Document 1, when a resin foam is used as a core material for a vacuum heat insulating material, since the foam is easily molded, the surface smoothness of the vacuum heat insulating material can be obtained relatively easily. On the other hand, when a laminated body of inorganic fibers such as glass fibers is used as a core material for a vacuum heat insulating material, a vacuum heat insulating material with better thermal performance can be obtained, and therefore a laminated body of inorganic fibers is widely used. However, when the laminated body of inorganic fibers is used as a core material, unlike the resin foam, the laminated body of inorganic fibers is not easy to mold. However, when embedded in the wall surface of a housing such as an electric refrigerator, there is a problem that sufficient thermal performance cannot be obtained. For this reason, although the surface smoothness can be obtained by increasing the thickness of the envelope bag of the vacuum heat insulating material, the envelope bag covers the entire core material, so that the thermal conductivity of the vacuum heat insulating material is reduced. As a result, there has been a problem that a vacuum heat insulating material having sufficient thermal performance cannot be obtained.

  Further, in the case of the technique described in Patent Document 2, although the surface smoothness of the obtained vacuum heat insulating material is excellent, since all surfaces of the core material are covered with a resin film, (1) heat insulation (2) Since a resin film inner bag is further present in the outer bag for vacuum heat insulating material, bending occurs at the end of the vacuum heat insulating material. (3) Core material in the inner bag There is a problem that the number of steps is large and the cost is high, such as an operation of inserting the bag, a process of degassing the bag, a process of inserting the bag into the jacket bag, and a task of degassing the jacket bag.

  Therefore, an object of this invention is to provide the vacuum heat insulating material excellent in heat insulation and surface smoothness with few processes at low cost.

The above object is achieved by the present invention described below. That is, the present invention is a vacuum heat insulating material in which a core material in which glass fibers are laminated is covered with an outer bag and the inner pressure of the outer bag is reduced, and at least one of both surfaces of the core material A vacuum heat insulating material is provided in which a sheet-like material with a basis weight of 20 to 400 g / m ² is inserted between the surface of the outer bag and the outer bag.

The present invention also includes a step of laminating glass fibers having an average fiber diameter of 5 μm or less to form a core material, a step of heating the core material at 80 to 350 ° C., and at least one surface of both surfaces of the core material. The method includes a step of laminating a sheet-like material having an amount of 20 to 400 g / m ² , a step of inserting the laminate into a jacket bag for a vacuum heat insulating material, and a step of decompressing the inside of the jacket bag. A method for producing a vacuum heat insulating material is provided.

  In the vacuum heat insulating material of the present invention, the sheet is a resin film having a thickness of 0.02 to 0.3 mm; the sheet is a non-woven fabric or a woven fabric having a thickness of 0.5 to 10 mm. It is preferable that the core material is a core material to which an organic binder is attached, and the amount of the organic binder attached to the core material is 0.1 to 3% by mass of the core material.

In the production method of the present invention, the step of laminating the glass fibers to form a core material is performed by attaching an organic binder to the glass fibers before or after laminating the glass fibers, and then heating the binder. Curing to obtain a core material to which an organic binder of 0.1 to 3% by mass of the core material is adhered; heating the core material to which the organic binder is adhered to 240 to 350 ° C .; After heating at 50 to 300 ° C., laminating the sheet material; including a step of compressing the glass fiber to a density of 150 to 500 kg / m ³ ; the sheet material having a thickness of 0.02 to 0 It is preferable that the resin film has a thickness of 3 mm; and the sheet-like material is a nonwoven fabric or a woven fabric having a thickness of 0.5 to 10 mm.

  ADVANTAGE OF THE INVENTION According to this invention, the vacuum heat insulating material excellent in heat insulation and surface smoothness can be provided at low cost with few processes.

Next, the present invention will be described in more detail with reference to the drawings showing the best mode for carrying out the invention.
FIG. 4 is a schematic cross-sectional view of a conventionally known vacuum heat insulating material. In FIG. 4, reference numeral A denotes the entire vacuum heat insulating material, reference numeral 1 denotes a state in which a core material made of an inorganic fiber mat is filled and compressed in the outer bag, reference numeral 2 denotes a gas barrier outer bag, and reference numeral 3. Indicates a sealing portion. In the illustrated vacuum heat insulating material A, a core material 1 made of an inorganic fiber mat such as glass fiber is covered with a gas barrier outer bag 2 such as an aluminum-deposited polyethylene film, and the inside of the outer bag is in a vacuum (reduced pressure) state (for example, 1 to 10 Pa).

  In the vacuum heat insulating material A, since the core material 1 made of an inorganic fiber mat is simply covered with the jacket bag 2, all of the inorganic fibers in the core material are horizontal in the plane direction of the vacuum heat insulating material. Therefore, the heat insulating property of the vacuum heat insulating material was insufficient. For the same reason, the surface of the outer bag 2 is inferior in smoothness when used as a vacuum heat insulating material, and in a case where various heat insulating properties such as a refrigerator and a personal computer are required, the case in which the heat insulating material is stored. In this case, a space was generated on the inner surface of the housing, which also caused poor heat insulation.

The vacuum heat insulating material of the present invention solves the above-described problem. As shown in FIG. 1, the weight per unit area 20 is between at least one surface of both surfaces of the core material 1 and the outer bag 2. It is characterized in that a sheet-like material B of ˜400 g / m ² is inserted. According to the present invention, the surface smoothness of the vacuum heat insulating material can be remarkably improved without increasing the manufacturing cost of the vacuum heat insulating material due to the above features.

When the basis weight of the sheet-like material B is less than 20 g / m ² , the resulting flat surface smoothness of the vacuum heat insulating material cannot be sufficiently obtained, and on the other hand, the basis weight of the sheet-like material B is 400 g. If it exceeds / m ² , the thermal performance is inferior when using a resin film, which will be described later, and if a non-woven fabric or woven fabric is used, no more planar smoothness can be expected, and the cost increases. It is not preferable. Therefore, the value is more preferably 100 to 250 g / m ² .

  The sheet-like material is preferably a resin film having a thickness of 0.02 to 0.3 mm. When the thickness is less than 0.02 mm, the resulting flat surface smoothness of the vacuum heat insulating material is not sufficiently obtained, and when the thickness exceeds 0.3 mm, the thermal performance of the vacuum heat insulating material is not preferable. Is inferior and is not preferred. Therefore, the thickness is more preferably 0.03 to 0.1 mm. Examples of the resin material include polyethylene terephthalate, polyethylene, polypropylene, polycarbonate, polyamide, and polyvinyl alcohol. The resin film may be a non-porous film or a porous film.

  Further, as the sheet-like material, a nonwoven fabric or a woven fabric having a thickness of 0.5 to 10 mm is also suitable. If the thickness is less than 0.5 mm, the resulting flat surface smoothness of the vacuum heat insulating material cannot be obtained sufficiently. On the other hand, if the thickness exceeds 10 mm, more flat smoothness can be expected. Moreover, it is not preferable in terms of high cost. Therefore, the thickness is more preferably 1 to 5 mm. Examples of the material of the nonwoven fabric or woven fabric include polyethylene terephthalate, polyethylene, polypropylene, polycarbonate, polyamide, polyvinyl alcohol, glass fiber, and the like, and it is more preferable to use the glass fiber in order to improve the thermal performance of vacuum insulation. . Although the size of said sheet-like material B is not specifically limited, It is preferable that it is the same shape as the core material 1 of a vacuum heat insulating material, or a somewhat small similar shape.

  Although the other structure and manufacturing method of the said vacuum heat insulating material of the said invention are not specifically limited, One example of a preferable manufacturing method is demonstrated with reference to FIG. 2 (A)-(D) below. FIG. 2 (A) shows a state in which a plurality of fiber mats 4 before compression are laminated, and FIG. 2 (B) shows a laminate of the fiber mats shown in FIG. FIG. 2 (C) shows a state where a compression mat obtained by releasing the laminated fiber mat from the press, that is, the core material 1 is formed. In addition, when using the inorganic fiber mat to which the press machine 5 was provided with the binder, it is preferable that the heating function is provided. In the present invention, the sheet-like material B is placed on both surfaces or one surface of the core material formed as described above as shown in FIG. When the sheet-like material B is placed, it may be simply placed without using an adhesive or the like, or may be point-bonded with a small amount of adhesive in order to improve workability.

The core material 1 (FIG. 2 (C)) used in the present invention is obtained by a method as shown in FIGS. 2 (A) and 2 (B) as an example. That is, for example, glass fiber is continuously laminated on a belt conveyor while continuously melt spinning, and further, if necessary, before and after lamination, an organic binder or an inorganic binder is applied and cured by heating. A sheet is formed into a glass fiber mat, and a plurality of the glass fiber mats 4 are cut and laminated from a roll of the mat (FIG. 2 (A)), and the density of the laminate is 150 to 500 kg. It is obtained by molding the core material 1 as a compression mat with a flat plate heating press 5 or the like for 30 seconds or more so as to be / m ³ (FIG. 2 (C)).

The glass fiber mat 4 before compression which constitutes the core material 1 is known per se, and is formed by molding glass fibers into a mat shape with the binder as necessary. Such glass fiber mats are known to have various densities. In the present invention, the average fiber diameter of the glass fibers is 5 μm or less, preferably 3 to 5 μm. Moreover, it is preferable that the density of the glass fiber mat before compression is 3 kg / m ³ or more, and the thickness of one piece of the mat is 10 to 350 mm.

When the average diameter of the glass fiber is more than 5 μm, the effect of the present invention cannot be sufficiently obtained in that the thermal performance of the obtained vacuum heat insulating material is lowered, while the thickness is less than 3 μm. This glass fiber is difficult to manufacture. Further, if the density of the glass fiber mat 4 before the compression treatment is less than 3 kg / m ³ , the handling property at the time of compression is inferior. Further, if the thickness of one mat is less than 10 mm, the mat is inferior in productivity and requires many mats. On the other hand, if the thickness exceeds 350 mm, the mat is compressed. The handling property of the glass fiber mat is inferior.

  In addition, the binder itself used as necessary in the present invention may be a binder used in the production of a conventionally known glass fiber mat, and preferably an aqueous solution of a phenol resin precursor that is a thermosetting resin can be used. . These binders are preferably used in a range in which the solid content of the binder occupies 0.1 to 3.0% by mass of the total amount of the glass fiber including the solid content of the binder. Mass% is most preferred. When the adhesion amount of these binders is less than 0.1% by mass, the glass fiber mat is bulky and the mat has flexibility, so that it is difficult to fill the core bag manufactured from the mat into the outer bag. In some cases, such as poor handling properties. On the other hand, if the amount of adhesion exceeds 3.0% by mass, the heat insulating performance of the resulting vacuum heat insulating material may be inferior, which may be undesirable. In addition, the present invention can use a glass fiber mat called white wool to which a binder is not applied, and white wool is more flexible than that to which a binder is applied, and thus has particularly sufficient surface smoothness. Although not obtained, since the surface smoothness is remarkably improved by using the sheet-like material B of the present invention, it is preferably employed.

In the present invention, the glass fiber mat is compressed alone or in a plurality of layers. The number of sheets to be laminated when a plurality of sheets are compressed is different depending on the density and thickness of the glass fiber mat and the thickness required for the vacuum heat insulating material finally obtained. For example, the density is 20 to 100 kg. / M ³ and a mat having a thickness of 10 to 50 mm can be compressed by stacking 2 to 4 mats, or 2 to 4 mats having been compressed can be used.

Further, the compression condition is a condition in which the density of the laminated and compressed mat is 150 to 500 kg / m ³ , preferably 200 to 400 kg / m ³ , specifically, between the upper and lower sides of the flat plate press. The pressure is 150 to 500 kg / m ² , preferably 200 to 400 kg / m ² . When the value is less than 150 kg / m ³ (density) or 150 kg / m ² (pressure), the surface smoothness of the vacuum heat insulating material filled with the obtained core material cannot be obtained sufficiently, and 500 kg / When m ³ (density) or 500 kg / m ² (pressure) is exceeded, the equipment for compressing the glass fiber mat becomes large, and the glass fiber in the glass fiber mat is bent more than necessary, and the glass fiber is Since it becomes powdery and sufficient thermal performance of the finally obtained vacuum heat insulating material cannot be obtained, it is not preferable. Moreover, the compression time is 30 seconds or more, and when compressing with the press machine, 60 to 360 seconds are preferable.

When the glass fiber mat compressed as described above is released from the pressure after the compression treatment, the thickness increases and becomes thicker (FIG. 2 (B) → FIG. 2 (C)). The density and thickness of the core material in this state are not particularly limited, but in general, the density is 45 to 100 kg / m ³ and the thickness is preferably 10 to 70 mm. The glass fiber which comprises the core material by such a compression process becomes substantially horizontal with respect to the plane direction, and the surface smoothness of the core material is improved. As a result, by using the compressed core material together with the sheet-like material B as the core material of the vacuum heat insulating material, a vacuum heat insulating material having excellent heat insulating properties, surface smoothness and workability can be obtained.

  Furthermore, when the said organic binder is used, it is preferable to heat-process a glass fiber mat before and behind the said compression, or simultaneously with compression, and it is preferable that the said heat processing is heated at 240-350 degreeC. Even with the heating, since the binder remains in the glass fiber mat, the surface smoothness of the core material itself is not impaired, and not only the hand rigging property of the core material is good, but also when the vacuum heat insulating material is used. Since it is excellent in heat insulation, it is preferable. Moreover, although the said heat processing time is based also on the adhesion amount of the binder before a heating, the heating for 5 minutes or more is preferable even if heating temperature is 350 degreeC vicinity, and about 30 minutes are preferable when heating temperature is 240 degreeC vicinity. Therefore, in the present invention, when the heating temperature is within the above range, a heating time of 5 minutes to 30 minutes is preferable.

  The binder adhesion amount of the core material after the heat treatment is preferably such that the solid content of the binder occupies 0.1 to 3.0% by mass of the total amount of the glass fiber including the solid content of the binder. 5-2.0 mass% is the most preferable. Moreover, it is preferable that the binder adhesion amount after heat processing has decreased 10 mass% or more with respect to the binder adhesion amount before a heating. When the adhesion amount of the binder of the core material after the heat treatment is less than 0.1% by mass, the glass fiber mat is bulky and the mat has flexibility. In some cases, it is difficult to fill the inside, such as poor handling properties. On the other hand, if the amount of adhesion exceeds 3.0% by mass, the heat insulating performance of the resulting vacuum heat insulating material may be inferior, which may not be preferable, but because the heat treatment is performed, the same amount of heat treatment is not performed. The heat-treated mat has better thermal performance than the mat, and the amount of binder attached can be relatively increased. Therefore, the surface smoothness of the core material itself is improved, and the bulk of the glass fiber mat is increased. It is possible to improve the handleability without causing the above.

  The manufacturing method of the core material described with reference to FIGS. 2A to 2D is a preferable example, and another preferable example of manufacturing the core material will be described with reference to FIG. In the figure, reference numeral 6 denotes a laminated fiber mat before compression, reference numeral 7 denotes a heating oven, reference numeral 8 denotes a compression conveyor, reference numerals 9 and 9 ′ denote a pair of upstream rolls, and reference numerals 10 and 10 ′ denote a downstream side. A pair of rolls, 11 is a laminated fiber mat being compressed, and 1 is a laminated mat (that is, a core material) manufactured by compression.

  In the core material manufacturing method shown in the figure, glass fibers that are continuously melt-spun are continuously matted on a conveying means (not shown) such as a belt conveyor at a predetermined density, and the glass fibers are matted. Without being wound into a roll (of course, the wound ones may be continuously rewound) to form a laminated fiber mat 6 which is laminated in a heating oven 7. The desired core material 1 can be continuously produced by continuously compressing with a pair of upstream rolls 9 and 9 'and a pair of downstream rolls 10 and 10' constituting the driven compression conveyor 8. Is preferable.

  Although the length of the conveyor 8 depends on the line speed, it is preferably 10 to 30 m. If the length of the conveyor 8 is less than 10 m, the compression becomes insufficient, and the core material 1 that gives a smooth vacuum heat insulating material cannot be obtained. On the other hand, if the length of the conveyor 8 exceeds 30 m, the apparatus is too large. This is not preferable. Moreover, when compressing continuously with a conveyor, it is 30 seconds or more, and it is preferable that it is 60 to 180 seconds. If the value is less than 30 seconds, the compression becomes insufficient and the core material 1 that gives a smooth vacuum heat insulating material cannot be obtained. On the other hand, if it exceeds 180 seconds, the production efficiency is inferior or the apparatus is large. This is not preferable because a vacuum heat insulating material having smoothness higher than expected cannot be obtained. Various suitable conditions (compression conditions, time, etc.) in this example are the same as those in the manufacturing method with reference to FIG.

  In the manufacturing method of the present invention, in order to improve the thermal performance of the vacuum heat insulating material, the core material 1 is coated in the outer bag except when the glass fiber mat in the case of using the organic binder described above is heat-treated. The core material 1 is characterized in that it is heated to 80 to 350 ° C. for the purpose of reducing moisture as soon as possible. Further, the heating is preferably performed by heating the sheet-like material B used in the present invention or by separately heating the sheet to 50 to 300 ° C. and laminating with the core material.

  When using the core material obtained by the above method as a vacuum heat insulating material, for example, the core material obtained by the present invention is covered with a sheet-like material with a gas barrier outer bag, and the inside of the outer bag is Obtained by degassing. Gas barrier jackets include polyester, polyethylene, polyvinyl chloride, polyvinylidene chloride, polystyrene, polypropylene and other resin films, kraft paper laminated with the above film, aluminum foil laminated with the above film, and the above film Those obtained by vapor-depositing aluminum are preferably used.

  Further, since the surface of the vacuum heat insulating material is smooth by using the core material and the sheet-like material in the manufacture of the vacuum heat insulating material, the housing for storing the heat insulating material when the heat insulating material is used. There is no space between the wall surface of the body and, therefore, the heat insulation is remarkably improved from this point. Furthermore, the surface smoothness of a vacuum heat insulating material improves more by using the core material compressed into the density of the specific range which is a preferable aspect of this invention.

Next, the present invention will be described in more detail with reference to examples and comparative examples.
[Example 1]
Glass fibers having an average fiber diameter of 4 μm were laminated in a mat shape, and wound in a roll shape in the form of white wool to which no binder was added (thickness: about 40 mm, density: 30 kg / m ³ ). This glass fiber mat was laminated on two plies, and was compressed with a flat plate press under conditions of a density of about 300 kg / m ³ during compression and a compression time of about 1 minute. Further, this mat was dried by heating in a constant temperature dryer under conditions of a temperature of about 200 ° C. and a drying time of about 10 minutes. Furthermore, both sides of this mat are sandwiched between PET (polyethylene terephthalate) films having a thickness of about 0.1 mm and a weight per unit area of 130 g / m ² , and this is put into a jacket bag having a high gas barrier property. After sucking so that the pressure was 1.0 Pa, the opening of the outer bag was heat-sealed to obtain a vacuum heat insulating material of the present invention having a thickness of 9 mm and a density of about 260 kg / m ³ .

[Example 2]
Glass fibers having an average fiber diameter of 4 μm were laminated in a mat shape, and wound in a roll shape in the form of white wool to which no binder was added (thickness: about 40 mm, density: 30 kg / m ³ ). This glass fiber mat was laminated on two plies, and was compressed with a flat plate press under conditions of a density of about 300 kg / m ³ during compression and a compression time of about 1 minute. Further, this mat was dried by heating in a constant temperature dryer under conditions of a temperature of about 200 ° C. and a drying time of about 10 minutes. Furthermore, both sides of this mat are sandwiched between glass fiber nonwoven fabrics having a thickness of about 2.5 mm and a weight per unit area of 260 g / m ² , and this is put into a jacket bag having a high gas barrier property, and the pressure in the jacket bag is measured by a vacuum seal device. Then, the opening of the bag was heat-fused to obtain a vacuum heat insulating material of the present invention having a thickness of 9 mm and a density of about 260 kg / m ³ .

[Example 3]
A vacuum heat insulating material of the present invention having a thickness of 9 mm and a density of about 260 kg / m ³ was obtained in the same manner as in Example 1 except that the thickness of the PET film was 0.05 mm and the basis weight was 70 g / m ² .

[Example 4]
Glass fibers having an average fiber diameter of 4 μm were laminated in a mat shape, and wound in a roll shape in the form of white wool to which no binder was added (thickness: about 40 mm, density: 30 kg / m ³ ). This glass fiber mat was laminated on two plies and dried by heating in a constant temperature dryer at a temperature of about 200 ° C. and a drying time of about 10 minutes. Further, the mat is sandwiched between both sides of a glass fiber non-woven fabric having a thickness of about 2.5 mm and a weight per unit area of 260 g / m ² , and this is put in a jacket bag having a high gas barrier property. After suction to 0.0 Pa, the opening of the bag was heat-fused to obtain a vacuum heat insulating material of the present invention having a thickness of 9 mm and a density of about 260 kg / m ³ .

[Example 5]
A glass fiber mat (thickness of about 300 mm, density of about 4 kg / m ³ ) obtained by spraying phenol binder on glass fibers having an average fiber diameter of 4 μm so that the gloss (loss by burning) is 1% by mass is passed through a hot air. While being sandwiched between upper and lower conveyors, the oven was compressed under the conditions of 260 ° C., oven residence time of about 1.5 minutes, and density at compression of 130 kg / m ³ . As a result, a glass fiber mat having a thickness of about 25 mm and a density of about 48 kg / m ³ was obtained. Further, this mat was laminated on two plies, and was heated by a constant temperature dryer at a temperature of about 250 ° C. for about 30 minutes. Further, the mat is sandwiched between both sides of a PET film having a thickness of about 0.1 mm and a basis weight of 130 g / m ² , and this is put in an outer envelope bag having a high gas barrier property. After suctioning to 0 Pa, the opening of the bag was heat-fused to obtain a vacuum heat insulating material of the present invention having a thickness of 10 mm and a density of about 240 kg / m ³ .

[Example 6]
A glass fiber mat (thickness of about 300 mm, density of about 4 kg / m ³ ) obtained by spraying phenol binder on glass fibers having an average fiber diameter of 4 μm so that the gloss (loss by burning) is 1% by mass is passed through a hot air. While being sandwiched between upper and lower conveyors, the oven was compressed under the conditions of 260 ° C., oven residence time of about 1.5 minutes, and density at compression of 130 kg / m ³ . As a result, a glass fiber mat having a thickness of about 25 mm and a density of about 48 kg / m ³ was obtained. Further, this mat was laminated on two plies, and was heated by a constant temperature dryer at a temperature of about 300 ° C. for about 30 minutes. Further, the mat is sandwiched between both sides of a PET film having a thickness of about 0.1 mm and a basis weight of 130 g / m ² , and this is put in an outer envelope bag having a high gas barrier property. After suctioning to 0 Pa, the opening of the bag was heat-fused to obtain a vacuum heat insulating material of the present invention having a thickness of 10 mm and a density of about 240 kg / m ³ .

[Example 7]
Furthermore, the thickness of the mat was 9 mm in the same manner as in Example 6 except that the PET film was heated at 70 ° C. for 10 minutes before being sandwiched between the PET films having a thickness of about 0.1 mm and a basis weight of 130 g / m ^2. A vacuum heat insulating material of the present invention having a density of about 260 kg / m ³ was obtained.

[Comparative Example 1]
Glass fibers having an average fiber diameter of 4 μm were laminated in a mat shape, and wound in a roll shape in the state of white wool to which no binder was added (thickness: about 40 mm, density: 30 kg / m ³ ). This glass fiber mat was laminated on two plies, and was compressed with a flat plate press under conditions of a density of about 300 kg / m ³ during compression and a compression time of about 1 minute. Further, this mat was dried by heating in a constant temperature dryer under conditions of a temperature of about 200 ° C. and a drying time of about 10 minutes. This is put into a jacket bag having a high gas barrier property, and sucked so that the pressure in the bag becomes 1.0 Pa with a vacuum sealing device, and then the opening portion of the bag is heated and fused, and the thickness is 9 mm, the density is about The vacuum heat insulating material of the comparative example of 260 kg / m < ³ > was obtained.

[Comparative Example 2]
Glass fibers having an average fiber diameter of 4 μm were laminated in a mat shape, and wound in a roll shape in the state of white wool to which no binder was added (thickness: about 40 mm, density: 30 kg / m ³ ). This glass fiber mat was laminated on two plies, and was compressed with a flat plate press under conditions of a density of about 130 kg / m ³ during compression and a compression time of about 5 minutes. Further, this mat was dried by heating in a constant temperature dryer under conditions of a temperature of about 200 ° C. and a drying time of about 10 minutes. This is put in a jacket bag having a high gas barrier property, and sucked so that the pressure in the bag becomes 1.0 Pa with a vacuum seal device, and then the opening of the bag is heat-fused, and has a thickness of 11 mm and a density of about A comparative vacuum heat insulating material of 220 kg / m ³ was obtained.

[Comparative Example 3]
Glass fibers having an average fiber diameter of 4 μm were laminated in a mat shape, and wound in a roll shape in the form of white wool to which no binder was added (thickness: about 40 mm, density: 30 kg / m ³ ). This glass fiber mat is laminated on two plies, and this is sandwiched with a punching plate together with a 15 mm thick spacer, and tightened to the thickness of the spacer with a jig to compress and fix white wool. This was placed in an electric furnace at 530 ° C. for 10 minutes. Then, the jig | tool and the plate were removed and the core material by which the fiber was heat-sealed was obtained. This is put into a jacket bag having a high gas barrier property, and sucked so that the pressure in the bag becomes 1.0 Pa with a vacuum sealing device, and then the opening of the bag is heat-fused, and the thickness is 10 mm, the density is about The vacuum heat insulating material of the comparative example of 240 kg / m < ³ > was obtained.

[Comparative Example 4]
A glass fiber mat (thickness of about 300 mm, density of about 4 kg / m ³ ) obtained by spraying a phenol binder on glass fibers having an average fiber diameter of 4 μm so that the gloss is 1% by mass is heated in a hot air passing oven. While being sandwiched between the upper and lower conveyors, compression was performed under the conditions of 260 ° C., oven residence time of about 1.5 minutes, and compression density of 130 kg / m ³ . As a result, a glass fiber mat having a thickness of about 25 mm and a density of about 48 kg / m ³ was obtained. Further, this mat was laminated on two plies, and was heated by a constant temperature dryer at a temperature of about 250 ° C. for about 30 minutes. This is put into a jacket bag having a high gas barrier property, and sucked so that the pressure in the bag becomes 1.0 Pa with a vacuum sealing device, and then the opening of the bag is heat-fused, and the thickness is 10 mm, the density is about The vacuum heat insulating material of the comparative example of 240 kg / m < ³ > was obtained.

[Comparative Example 5]
A glass fiber mat (thickness of about 300 mm, density of about 4 kg / m ³ ) obtained by spraying a phenol binder on glass fibers having an average fiber diameter of 4 μm so that the gloss is 1% by mass is heated in a hot air passing oven. While being sandwiched between the upper and lower conveyors, compression was performed under the conditions of 260 ° C., oven residence time of about 1.5 minutes, and compression density of 130 kg / m ³ . As a result, a glass fiber mat having a thickness of about 25 mm and a density of about 48 kg / m ³ was obtained. Further, this mat was laminated on two plies, and was heated by a constant temperature dryer at a temperature of about 300 ° C. for about 30 minutes. This is put into a jacket bag having a high gas barrier property, and sucked so that the pressure in the bag becomes 1.0 Pa with a vacuum sealing device, and then the opening of the bag is heat-fused, and the thickness is 10 mm, the density is about The vacuum heat insulating material of the comparative example of 240 kg / m < ³ > was obtained.

  The production conditions of the above examples and comparative examples are shown in Table 1 below. “WW” in the table means white wool, and “organic product” indicates the use of an organic binder. The gloss before heating and after heating shows the respective ignition losses before and after heating.

[Evaluation methods]
The surface smoothness and thermal conductivity of the vacuum heat insulating materials of the above Examples and Comparative Examples were evaluated by the following evaluation methods, and the results shown in Table 2 below were obtained.
[Evaluation methods]
1. Surface smoothness:
◎: Concavities and convexities are small, and the depth of the concavity is less than 1 mm (appearance photograph of actual sample is shown in Fig. 5)
○: There are slight irregularities, and the depth of the recess is 1 mm or more and less than 2 mm (appearance photograph of the actual sample is shown in FIG. 6).
Δ: Intermediate level between ○ and × (appearance photograph of actual sample is shown in FIG. 7)
×: Concavities and convexities are large, and the depth of the concavity is 2 mm or more (appearance photograph of actual sample is shown in FIG. 8)
2. Thermal conductivity:
Measured with Hidehiro Seiki (HC-074-300)

  ADVANTAGE OF THE INVENTION According to this invention, the vacuum heat insulating material excellent in heat insulation and surface smoothness can be provided at low cost with few processes.

The figure which illustrates the structure of the vacuum heat insulating material of this invention schematically. The figure which illustrates the manufacturing method of a core material schematically. The figure which illustrates schematically the other method of the manufacturing method of a core material. The figure which illustrates the structure of the conventional vacuum heat insulating material schematically. Appearance photograph of actual sample used for evaluation of surface smoothness (evaluation ◎) Appearance photograph of an actual sample used for evaluation of surface smoothness (evaluation ○) Appearance photograph of actual sample used for evaluation of surface smoothness (evaluation △) Appearance photograph of actual sample used for evaluation of surface smoothness (evaluation x)

Explanation of symbols

A: Vacuum heat insulating material B: Sheet material 1: Core material 2: Jacket bag 3: Sealing portion 4: Laminated fiber mat before compression 5: Flat plate press 6: Laminated fiber mat before compression 7: Heating oven 8 : Compression conveyors 9, 9 ': A pair of upstream rolls 10, 10': A pair of downstream rolls 11: Laminated fiber mats during compression

Claims (11)

A vacuum heat insulating material in which a core material formed by laminating glass fibers is covered with an outer bag, and the inner pressure of the outer bag is reduced, and at least one surface of both surfaces of the core member and the outer cover A vacuum heat insulating material, wherein a sheet-like material having a basis weight of 20 to 400 g / m ² is inserted between the bag and the bag.   The vacuum heat insulating material according to claim 1, wherein the sheet-like material is a resin film having a thickness of 0.02 to 0.3 mm.   The vacuum heat insulating material according to claim 1, wherein the sheet-like material is a nonwoven fabric or a woven fabric having a thickness of 0.5 to 10 mm.   The core material is a core material to which an organic binder is attached, and the amount of the organic binder attached to the core material is 0.1 to 3% by mass of the core material. Vacuum insulation material. A step of laminating glass fibers having an average fiber diameter of 5 μm or less to form a core, a step of heating the core at 80 to 350 ° C., and a basis weight of 20 to 400 g / m on at least one surface of both surfaces of the core ^2. A method for producing a vacuum heat insulating material, comprising the step of laminating the sheet-like material of ² , a step of inserting the laminated material into a jacket bag for a vacuum heat insulating material, and a step of depressurizing the inside of the outer bag. .   The step of laminating the glass fiber to form a core material is performed by attaching an organic binder to the glass fiber before or after laminating the glass fiber, and then heating to cure the binder, The manufacturing method of the vacuum heat insulating material of Claim 5 made into the core material which 3 mass% organic binder adhered.   The manufacturing method of the vacuum heat insulating material of Claim 6 which heats the core material to which the said organic binder was adhered at 240-350 degreeC.   The manufacturing method of the vacuum heat insulating material of Claim 5 which laminates | stacks this sheet-like material after heating the said sheet-like material at 50-300 degreeC. The manufacturing method of the vacuum heat insulating material of Claim 5 including the process of compressing the said glass fiber to a density of 150-500 kg / m < ³ >.   The method for producing a vacuum heat insulating material according to claim 5, wherein the sheet-like material is a resin film having a thickness of 0.02 to 0.3 mm.   The method for producing a vacuum heat insulating material according to claim 5, wherein the sheet-like material is a nonwoven fabric or a woven fabric having a thickness of 0.5 to 10 mm.