JP2003155651A - Vacuum heat insulation material and core material for vacuum heat insulation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a core material for a vacuum heat insulation material that includes no impurity causing the outgassing and has high communicating ability, excellent handleability and heat resistance and to provide a vacuum heat insulation material that does not need to enclose an adsorbent, can retain the shape because it has high resistance to the atmospheric pressure, causing no occurrence of dust, has excellent heat insulation performance without outgassing and deterioration in the adiabatic performance. SOLUTION: The core material for vacuum heat insulation material comprises is composed of at least glass wool and thermoplastic resin fiber. The vacuum heat insulation material comprises the core material and a vessel that receives the core material and can keep the inside in vacuum. In a preferred embodiment, the thermoplastic resin fiber is bonded to the glass wool by hot-melting and pressing. In a particularly preferred embodiment, the average diameter of the thermoplastic resin fiber is <=20 μm and the content of the resin fiber is >=1 wt.%.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum heat insulating material and a core material for a vacuum heat insulating material, more specifically, a refrigerator,
Various types of heat insulation such as freezer, warmer, cold storage car, cold storage
The present invention relates to a vacuum heat insulating material that is suitably used for heating / cooling equipment, has excellent handleability, has high pressure resistance against atmospheric pressure, can maintain a shape, and has excellent heat insulating performance, and a core material for the vacuum heat insulating material.

[0002]

2. Description of the Related Art Conventionally, for example, a gas barrier is used as a heat insulating / heating / cooling device for household refrigerators, freezers, heat insulators, commercial showcases, etc. In a container in which a flexible film is formed in a bag shape, a packing body containing a powdered material such as perlite powder in an inner bag made of breathable non-woven fabric is stored, and the container is evacuated in this storage state. Those that are hermetically sealed and the inside of which is kept in a vacuum have been used (Japanese Patent Laid-Open No. 62-62-62).
No. 13979, etc.).

However, in the above vacuum heat insulating material, when the filling body formed by accommodating the powdery material in the inner bag of the non-woven fabric is put into the container having the gas barrier property and evacuated to bring the inside into a vacuum state, There are problems that the container is affected by the shape of the powder, wrinkles and irregularities are generated on the container itself, the contact state with the exterior material is deteriorated, and dust is generated by the powder.

Further, as the vacuum heat insulating material, in recent years, open cell urethane (communicating urethane) obtained by foaming hard urethane to make cells communicate with each other, or expanded polystyrene obtained by extrusion molding to make cells communicate with each other is required. There is also used one that is cut into a size, placed in a container having a gas barrier property together with an adsorbent, exhausted from the inside, hermetically sealed, and held inside in a vacuum state.

However, the above-mentioned urethane production method is a two-component method.
Since it is a curing reaction of
The generated outgas is generated and the heat insulation performance of the vacuum heat insulating material is improved.
There is a problem of lowering it. In addition, the continuous bubbles
In organic foam such as styrofoam, bubbles are completely removed.
It is difficult to form a 100% interconnected
Some closed air bubbles remain, so is it a blowing agent such as isobutane?
CO generated from₂Phenomenon that remains in the closed bubbles
Happens. For this reason, open-cell Styrofoam
Put it in a container with a barrier property and airtightly seal it after exhausting from the inside.
Even if stopped, the CO remaining in the closed bubbles ₂Due to
Outgassing gradually reduces the insulation performance of vacuum insulation materials
There is also the problem of doing.

In order to solve the above-mentioned problems, it is indispensable to enclose an adsorbent (getter) together with a core material in a container used as a vacuum heat insulating material to adsorb generated gas to prevent deterioration of heat insulating performance. Even if the adsorbent is enclosed, it is difficult to completely prevent the deterioration of the heat insulation performance due to the outgas.

Therefore, in recent years, the shape does not change due to the atmospheric pressure during evacuation, no dust is generated, the foaming agent and the adsorbent are not required, and the heat insulating property is excellent. There is a demand for the development of a vacuum insulation core material that does not deteriorate the heat insulation performance.

Under such circumstances, there has been proposed a material using non-alkali long fiber glass wool as a core material for a vacuum heat insulating material as a material replacing the pearlite powder, the open cell urethane, the open cell styrofoam and the like. The non-alkali long-fiber glass wool has very high heat insulation performance, and since it has continuity, there is no outgas and no adsorbent is required.
It has the advantage that no foaming agent is required. On the other hand, glass wool has a low bulk density (density) (20 kg / m
³ )), when only glass wool is used as the core material for the vacuum heat insulating material, the density after being put in the container for the vacuum heat insulating material and evacuated becomes 400 kg / m ³ or more, and is compressed 10 times or more. Therefore, there were problems such as inconvenience in handling (handling) and transportation surface (delivery) at the time of manufacturing, low pressure resistance against atmospheric pressure and easy deformation, and the need for a large vacuum heat insulating material container. .

In order to solve the above problems, Japanese Patent Laid-Open No. 7-96
In Japanese Patent No. 563, a vacuum heat insulation in which the density of the core material for a vacuum heat insulating material is increased in advance by subjecting a pile of glass wool to a needle punching process and the volume shrinkage after being housed in a container and evacuated is suppressed to be small Wood is proposed. In this vacuum heat insulating material, the needle punching process enables the glass wool to be entangled and hardened, and the density of the core material can be increased in advance. Furthermore, the processing such as hardening the glass wool with an organic binder or the like can be performed. Since it is not necessary, it is excellent in that there is no concern about outgas generated from the organic binder. However, since only glass wool is used as the material of the core material, there is a problem in that it is difficult to put it into practical use in terms of cost.

Therefore, in Japanese Patent Application Laid-Open No. 9-136367, there is disclosed a cost-effective vacuum heat insulating material in which glass wool is mixed with an inexpensive fibrous material such as pulp or rock wool as a core material. Has been proposed,
At present, no one has been found that has the same heat insulating performance as that of the vacuum heat insulating material using only glass wool.

[0011]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems in the prior art and achieve the following objects. That is, the present invention does not contain impurities that cause outgas such as unreacted substances, foaming agents, and organic binders, has communication, is excellent in handleability and heat resistance, is easy to transport, and has a heat insulating property. A core material for a vacuum heat insulating material with excellent performance, and a shape that has high pressure resistance against atmospheric pressure when vacuuming is performed without the need to enclose an adsorbent when the core material for a vacuum heat insulating material is stored in a container. It is an object of the present invention to provide a vacuum heat insulating material which can maintain the above-mentioned properties, does not generate dust, has excellent heat insulation performance, does not generate outgas, and does not deteriorate in heat insulation performance.

[0012]

Means for Solving the Problems As a result of intensive studies to achieve the above object, the present inventors have used a core material for a vacuum heat insulating material containing glass wool and a thermoplastic resin fiber, and the core material. The present inventors have completed the present invention by finding that the vacuum heat insulating material has excellent heat insulating performance and that the heat insulating performance does not deteriorate. Therefore, the means for solving the above problems are as follows. That is, <1> A core material for a vacuum heat insulating material comprising glass wool and a thermoplastic resin fiber.

<2> The vacuum according to <1>, wherein the thermoplastic resin fiber is adhered to the glass wool by heating, melting and pressurizing while maintaining the communication between the glass wool and the thermoplastic resin fiber. It is a core material for heat insulating materials.

<3> The average fiber diameter of the glass wool is 20 μm or less, the average fiber diameter of the thermoplastic resin fibers is 100 μm or less, and the content of the thermoplastic resin fibers is 1% by weight or more. The core material for a vacuum heat insulating material according to <1> or <2>.

<4> The average fiber diameter of the glass wool is 0.6 μm or more and 9 μm or less, the average fiber diameter of the thermoplastic resin fiber is 1 μm or more and 15 μm or less, and the content of the thermoplastic resin fiber is 10 The core material for a vacuum heat insulating material according to any one of <1> to <3>, which is from 20% by weight to 20% by weight.

<5> The melting point of the thermoplastic resin fiber is
The core material for a vacuum heat insulating material according to any one of <1> to <4>, which is 250 ° C. or lower.

<6> The vacuum heat insulation according to any one of <1> to <5>, wherein the thermoplastic resin fiber contains at least one of polypropylene, acrylic, polyethylene terephthalate, polyamide, and polyethylene. It is a core material for wood.

<7> A step of mixing the glass wool and the thermoplastic resin fiber and opening them to obtain a cotton-like mixture, a step of laminating the cotton-like mixture, and a needle punching process on the laminated cotton-like mixture. <1> manufactured by a method for manufacturing a core material for a vacuum heat insulating material, which comprises a step of forming a mat by applying, a step of hot-pressing the mat and then compression-molding by cooling
To <6>, the vacuum heat insulating material core material.

<8> In the step of forming a mat by subjecting the laminated cotton-like mixture to needle punching, among the plurality of barbs provided in the needle used for the needle punching, the tip of the needle is used. The barb provided in the laminated cotton-like mixture does not penetrate the laminated cotton-like mixture, and the depth in the thickness direction of the laminated cotton-like mixture is 5
The core material for a vacuum heat insulating material according to <7>, wherein the barb is clamped at a position of 0% or more and 90% or less and needle punching is performed.

<9> In the step of hot-pressing the mat and then compression-molding it by cooling, the hot-press applies a pressure of 0.1 kg / cm ² or more to the mat of 90 ° C. or more. <7> or <8>, which is performed by heating at a temperature of 250 ° C. or lower
The core material for a vacuum heat insulating material according to 1.

<10> The core material for a vacuum heat insulating material according to any one of claims 1 to 9, which has a density of 150 kg / m ³ or more and 400 kg / m ³ or less.

<11> At least the core material for a vacuum heat insulating material according to any one of the above <1> to <10>, and a container for accommodating the core material for a vacuum heat insulating material and capable of maintaining a vacuum inside. This is a vacuum heat insulating material.

<12> The vacuum heat insulating material according to <11>, which has a density of 150 kg / m ³ or more and 400 kg / m ³ or less.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION The core material for vacuum heat insulating material and the vacuum heat insulating material of the present invention will be described in detail below. The vacuum heat insulating material of the present invention is capable of accommodating the vacuum heat insulating material core material of the present invention (hereinafter sometimes simply referred to as “core material”) and the vacuum heat insulating material core material to maintain a vacuum inside. At least, a container (hereinafter, may be simply referred to as a “container”). First, the core material for a vacuum heat insulating material of the present invention housed in the container will be described here.

(Core Material for Vacuum Insulation Material) The core material for vacuum insulation material of the present invention is characterized by containing glass wool and thermoplastic resin fiber. As a material for the vacuum insulation core material, not only glass wool but also a thermoplastic resin fiber mixed in the core material is included in the core material, and the cost is kept low, and the same heat insulation performance as that of glass wool alone is achieved. It is preferable from the viewpoint that no outgas is generated.

Further, it is preferable that the thermoplastic resin fiber is adhered to the glass wool by heating, melting and pressing while maintaining the continuity of the glass wool and the thermoplastic resin fiber. That is, by heating, melting and pressing a mixture of glass wool and the thermoplastic resin fiber, the contact portion between the glass wool and the thermoplastic resin fiber adheres to increase the pressure resistance, and the density is increased in advance. Since it can be kept in advance, it is possible to suppress the deformation and the volume shrinkage during evacuation. That is, the thermoplastic resin fiber also functions as a binder.

Further, the average fiber diameter of the glass wool is 20 μm or less, the average fiber diameter of the thermoplastic resin fibers is 100 μm or less, and the content of the thermoplastic resin fibers is 1% by weight or more. More preferable. Glass wool has a tendency that the smaller the average fiber diameter, the higher the heat insulating performance.

<Glass Wool> The glass wool (non-alkali long fiber glass wool) is not particularly limited as long as it is glass wool, but the average fiber diameter is 20 μm.
The following are preferably used, those of 9 μm or less are more preferable, and those of 6 μm or less are most preferably used. As a commercially available product, for example, glass wool manufactured by Nippon Glass Fiber Industry Co., Ltd. is preferably used.

<Thermoplastic Resin Fiber> As the thermoplastic resin fiber, fibers made of a resin having thermoplasticity can be used, but those having an average fiber diameter of 100 μm or less are preferably used, and 1 μm to 15 μm. Those having a thickness of 9 μm to 10 μm are most preferably used. By including the thermoplastic resin fiber having a small average fiber diameter, the heat insulating performance of the glass wool itself is not deteriorated, outgas is hardly generated, and the cost can be suppressed to be low. The melting point of the thermoplastic resin is preferably 250 ° C. or lower, more preferably 180 to 220 ° C., from the viewpoint of heating and melting and applying pressure.

Preferred examples of the material used for the thermoplastic resin fiber include polypropylene, acrylic, polyethylene terephthalate, polyamide and polyethylene, and the thermoplastic resin fiber containing at least one of them is preferable. preferable. These may be used alone or in combination of two or more. Among the preferable thermoplastic resin fibers, polypropylene resin fibers are most preferable from the viewpoints of versatility, cost, performance and the like.

In the core material for a vacuum heat insulating material of the present invention, the content of the thermoplastic resin fiber is preferably 1% by weight or more, more preferably 1% by weight or more and 30% by weight or less.
It is more preferably 0% by weight or more and 20% by weight or less. When the content of the thermoplastic resin fiber is less than 1% by weight,
The fixation of the fibers by adhesion becomes insufficient, and the effect of the present invention cannot be obtained. On the other hand, if it exceeds 30% by weight,
In the manufacturing process, it becomes difficult to perform needle punching processing described later.

On the other hand, the content of the glass wool is 70% by weight from the viewpoint of obtaining sufficient heat insulation performance.
It is preferably 99% by weight or more and 80% by weight or more and 90% by weight or less. In the core material for vacuum heat insulating material of the present invention, as the content of the thermoplastic resin fiber and the glass wool, the same heat insulating performance as in the case of only glass wool is obtained, and from the viewpoint of being suitable for needle punching processing described below, A ratio of 20% by weight of the thermoplastic resin fibers and 80% by weight of the glass wool is the most preferable embodiment.

<Other Components> In the core material for a vacuum heat insulating material of the present invention, in addition to the glass wool and the thermoplastic resin, other components may be contained within a range not deteriorating the performance of the present invention. it can. Suitable examples of other components include rock wool, pulp, and ceramic fibers.

<Manufacturing Method of Vacuum Insulation Core Material> Next,
A preferred embodiment of the method for producing a core material for a vacuum heat insulating material according to the present invention will be described. The vacuum heat insulating material core material of the present invention,
A step of mixing and opening the glass wool and the thermoplastic resin fiber to obtain a cotton-like mixture (hereinafter, referred to as "mixing and opening step").
Sometimes called. ), A step of laminating the cotton-like mixture (hereinafter, also referred to as “laminating step”), a step of forming a mat by subjecting the laminated cotton-like mixture to needle punching (hereinafter, “needle”). A core material for a vacuum heat insulating material, which includes a step of hot pressing the mat and a step of compression-molding by cooling the mat (hereinafter, also referred to as a "compression molding step"). It is preferably manufactured by the manufacturing method of. Hereinafter, each step will be described.

-Mixing and opening step-First, in the mixing and opening step, an appropriate amount of glass wool and thermoplastic resin are evenly mixed and opened to obtain a cotton-like mixture. At this stage, the cotton-like mixture has a density (bulk specific gravity) of about 10 to 20 kg / m ³ and is in a very bulky state.

-Laminating Step- In the next laminating step, the cotton-like mixture is sprayed onto a belt conveyor or the like to be placed on a line and laminated in a strip shape to form a thin laminate of the cotton-like mixture. Using a device such as a cross layer,
About 30 to 40 layers are laminated to obtain a laminate of the cotton-like mixture.

-Needle punching step-In the next step, the layered product of the cotton-like mixture obtained in the layering step is subjected to needle punching using a needle punching device. Here, the needle punching process will be described.

The needle punching process is, specifically, in the needle punching device, a member provided with a large number of needles (needle) having a plurality of small fishing hook-shaped barbs on the side surface is provided with respect to the band-shaped laminate. By repeating the operation of piercing in the vertical direction (thickness direction) and pulling up the member from that state, the fibers are entangled and pulled in the barb, so that the fibers inside the laminate are entangled and fixed, and the mat Are formed.

In the needle punching process,
Of the plurality of barbs provided on the needle (needle),
The barb provided at the tip of the needle does not penetrate the laminated cotton-like mixture, and the barb is placed at a position of 50% or more and 90% or less in the depth direction of the laminated cotton-like mixture. It is particularly preferable to hold and subject to needle punching. If the barb provided at the most distal end of the needle penetrates the cotton-like mixture, holes will be created by the needle in the formed mat, and this may be the cause of lowering the heat insulation performance of the core material. . Therefore, it is preferable to keep the barb provided at the most distal end of the needle to the opposite surface without penetrating the barb within the above depth range.

The needle punching process is preferably performed from the viewpoint that it is possible to form a mat excellent in handleability by compressing the cotton-like mixture without impairing the continuity in the laminate. The mat obtained by the needle punching step is fixed by the entanglement of the fibers, and the density (bulk specific gravity) is 80.
It has a value of about 100 kg / m ³ .

-Compression molding step-The mat obtained by the needle punching step is
It is further compressed in the compression molding step of the next step, and is strongly fixed by adhesion of fibers. Specifically, the mat is hot pressed. The hot press processing is to compress the mat itself to reduce the volume (increase the density) by applying heat while applying pressure to the surface of the mat, and at the same time, to melt the thermoplastic resin fibers present inside the mat, Then, by cooling, the contact portion between the thermoplastic resin fiber and the glass wool is firmly adhered and fixed. The hot pressing is preferable from the viewpoint that the strength of the core material can be increased and the core material can be compressed in a short time because the resin is quickly solidified by cooling the thermoplastic resin fiber after heat melting.

As the conditions for the hot pressing, it is particularly preferable to heat the mat at a temperature of 90 ° C. to 250 ° C. while applying a pressure of 0.1 kg / cm ² or more. The pressure is 0.1 kg / cm
^{When it is} less than ² , the adhesion between fibers becomes insufficient. If the temperature is lower than 90 ° C., the thermoplastic resin fibers are not completely melted and the adhesion is insufficient. On the other hand,
When a temperature higher than 250 ° C. is applied, the thermoplastic resin fibers are completely melted and block the communication between the fibers, which makes vacuuming difficult, which is not preferable.

The core material for a vacuum heat insulating material of the present invention is manufactured through the mixing opening step, the laminating step, the needle punching step, and the compression molding step.
The core material for a vacuum heat insulating material obtained through the above steps has a density in the range of 150 kg / m ³ or more and 400 kg / m ³ or less, and the density of the core material manufactured only from glass wool is 4
It becomes larger than 00 kg / m ³ , but the handling becomes easy. The core material for vacuum heat insulating material of the present invention has a density of 200 kg / m ³ or more and 300 or more.
It is preferably not more than kg / m ³ .

(Vacuum Insulation Material) Here, the vacuum insulation material of the present invention will be described. The vacuum heat insulating material of the present invention is characterized by at least including the core material for vacuum heat insulating material of the present invention, and a container for accommodating the core material for vacuum heat insulating material and capable of maintaining a vacuum inside.

First, a preferred embodiment in the manufacturing process of the vacuum heat insulating material of the present invention will be described with reference to the drawings. Figure 1
FIG. 1 is an example of a cross-sectional view of a main part of a vacuum heat insulating material in the present invention. The core material 10 for a vacuum heat insulating material of the present invention obtained through the above-mentioned manufacturing process has an appropriate size and shape (for example, a quadrangle).
Cut into pieces and dry to remove water contained inside. Next, the cut and dried core material 10 for a vacuum heat insulating material is placed in a container 18 that constitutes one surface of a container that can store the core material and can maintain a vacuum inside, and the other of the containers After covering the container 18 constituting the surface of
Heat seal the three sides. This is placed in a vacuum tank (not shown) and evacuated, and the degree of vacuum in the container 18 is set to 13.3.
The vacuum heat insulating material 16 of the present invention is formed by setting the pressure to Pa to 1.33 Pa (0.1 to 0.01 Torr) and heat-sealing the remaining one side.

Any container can be used as the container 18 as long as it has a gas barrier property, can be heat-sealed, and can accommodate the core material and maintain a vacuum inside. , Nylon, aluminum vapor deposition P
A container using a gas barrier film having a four-layer structure of ET (polyethylene terephthalate), aluminum foil, and high density polyethylene is preferably used.

Although only the core material 10 is put in the container 18, the vacuum heat insulating material 16 having heat insulating performance and less deterioration in heat insulating performance can be obtained, but the heat insulating performance is deteriorated due to a slight amount of outgas. It is also preferable to further encapsulate an adsorbent for prevention.

[0048] Density of the vacuum heat insulating material for the core material 10 in the vacuum heat insulating material 16 of the present invention, by being evacuated, and ^{150kg / m 3 ~400kg / m 3} . In the present invention, since the core material 20 for the vacuum heat insulating material is processed to have a high density in advance in the manufacturing process, there is no rapid volume contraction due to vacuuming, deformation of the container, wrinkles or irregularities on the container surface occur. do not do. Vacuum heat insulating material 1 of the present invention
Regarding the heat insulation performance of No. 6, the same performance as that obtained when only glass wool is used as the core material is obtained, and the heat insulation performance is superior to the vacuum heat insulation material made of continuous urethane foam or the like. Further, there is almost no deterioration in heat insulation performance over time.

Next, an example of using the vacuum heat insulating material of the present invention as a heat insulating material for a refrigerator will be described with reference to the drawings. FIG. 2 is an example of a fragmentary sectional view of a refrigerator using the vacuum heat insulating material of the present invention.

In FIG. 2, the refrigerator 21 has an outer box 22.
A heat insulating material 23 arranged inside the outer box 22, an inner box 24 arranged inside the heat insulating material 23, and a heat insulating door 25 for opening and closing the opening of the inner box 24. . The vacuum heat insulating material 26 of the present invention is attached in contact with the inner wall of the outer box 22, and the polyurethane foam 27 is filled between the outer box 22 and the inner box 24 to form the heat insulating material 23.
This heat insulating material 23 has a low thermal conductivity (high heat insulating performance).
Since the thermal conductivity can be suppressed low by using the vacuum heat insulating material 26 of the present invention, the heat insulating material 26 in the refrigerator 21 can be suppressed.
It is possible to reduce the wall thickness of.

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

<Production of vacuum heat insulating material> Average fiber diameter is 5 to 6
After mixing 80 parts by weight of glass wool (manufactured by Nippon Glass Fiber Industry Co., Ltd.) having a size of μm with 20 parts by weight of polypropylene resin fiber having an average fiber diameter of 9 to 10 μm and opening the mixture to form a cotton-like mixture, The cotton-like mixture was thinly laminated in a strip shape, and a cross-layer device was used to obtain a laminate of the cotton-like mixture. Next, this laminate was matted using a needle punching device. The obtained mat was hot pressed at a temperature of 210 ° C. and a pressure of 20 kg /
It was hot-pressed for 2 minutes under the condition of cm ² and then air-cooled. The compression-molded mat was cut into 200 cm × 200 cm, dried, and then placed in a container made of a gas barrier film (manufactured by Toyo Aluminum Co., Ltd.), which was evacuated in a vacuum chamber to reduce the internal pressure to 1 .33 Pa (0.01
Torr). And by sealing the container,
The vacuum heat insulating material sample of Example 1 was prepared.

<Adiabatic Performance of Vacuum Insulation Material> In the production of the vacuum insulation material of Example 1, Example 1 was repeated except that the core material was changed to the type and fiber diameter shown in Table 1 below. The vacuum heat insulating materials of Comparative Examples 1 to 6 were produced in the same manner as in. Then, the heat insulating performance of the vacuum heat insulating material of the present invention (Example 1) and the heat insulating performance of the vacuum heat insulating materials of Comparative Examples 1 to 6 were measured. The results are shown in Table 1 below.

[0053]

[Table 1]

From the results shown in Table 1, Comparative Examples 1 to 5 in which only glass wool having different average fiber diameters was used as the core material
It was confirmed that in the vacuum heat insulating material, the smaller the average fiber diameter, the lower the thermal conductivity and the higher the heat insulating performance. The vacuum heat insulating material of Example 1 was used as a core material by mixing polypropylene fibers having an average fiber diameter of 5 to 6 μm and glass wool having an average fiber diameter of 9 to 10 μm (about 1.5 denier). It was confirmed that, although the thermal conductivity was slightly higher than that of glass wool having an average fiber diameter of 5 to 6 μm (Comparative Example 3), it had substantially the same heat insulation performance.

<Heat resistance, long-term heat resistance, heat insulating performance and density of vacuum heat insulating material> The vacuum heat insulating material of the present invention (Example 1) obtained above, continuous cell urethane obtained by foaming hard urethane Insulating material (comparative example 7) using (communicating urethane) as a core material, and in the vacuum insulating material of the present invention of example 1, only the glass wool having an average fiber diameter of 5 to 6 μm without containing thermoplastic resin fibers. With respect to the vacuum heat insulating material (Comparative Example 3) produced in the same manner as the vacuum heat insulating material of the present invention, except that the above was used, the heat insulating performance, the density of the heat insulating material after vacuuming, the heat resistance, and the long-term heat resistance were measured and The evaluation was performed and the results are shown in Table 2 below. It also showed whether an adsorbent was needed.

The evaluation of the heat insulation performance is made by "Auto λ
HC-073 "(manufactured by Eiko Seiki Co., Ltd.) was used to measure the thermal conductivity. The heat resistance was evaluated by leaving it in a constant temperature bath and measuring the dimensional change rate after standing, and the long-term heat resistance was evaluated by leaving it in the constant temperature bath.
The thermal conductivity was measured by measuring the change with time.

[0057]

[Table 2]

From the results of Table 2 above, the vacuum heat insulating material of the present invention is excellent in heat insulating performance as compared with the continuous urethane, and shows substantially the same heat insulating performance as the case where only glass wool is used as the core material. It was confirmed. Further, the degree of denseness of the heat insulating material after vacuuming is 3 in the present invention.
From what has been reduced to 00kg / m ^3, compared to the heat insulating material comprising only glass wool density after vacuuming becomes 400 kg / m ^3, the volume shrinkage is small has been confirmed. It was also found that the vacuum heat insulating material of the present invention is also very excellent in heat resistance and long-term heat resistance.

<Adiabatic Performance and Strength Depending on Content of Thermoplastic Resin Fiber> Here, in the vacuum heat insulating material of the present invention of Example 1, the contents of glass wool and polypropylene resin fiber were changed as shown in Table 3 below. Samples of the vacuum heat insulating materials of Examples 2 and 3 were prepared in the same manner as in Example 1 except for the above. Then, in the same manner as in Example 1,
The heat insulating properties of the vacuum heat insulating materials of Examples 1 to 3 and Comparative Example 3 (only glass wool) were evaluated by measuring the thermal conductivity. Furthermore, the strength as a vacuum heat insulating material is measured by a panel bending test using a compression tester,
The one with low strength is ×, the one with slightly low strength is △,
The one with normal strength is ◯, the one with high strength is ◎,
evaluated. The measurement and evaluation results are shown in Table 3 below.

[0060]

[Table 3]

From the results in Table 3 above, it was confirmed that when the content of glass wool is large, the heat insulating performance is high, while when the content of the thermoplastic resin fiber is large, the strength of the heat insulating material tends to increase. .

<Density Change of Core Material by Vacuum Evacuation> Here, in the production of the vacuum heat insulating material of Example 1, needle punching and a core punching process were performed so that the density of the core material before vacuuming would be the values shown in Table 4 below. Samples of the vacuum heat insulating materials of Examples 4 to 8 were produced in the same manner as in Example 1 except that the hot pressing conditions were changed. Then, after vacuuming under the same conditions as in Example 1, the densities of the vacuum heat insulating materials were measured for Examples 4 to 8, and the results are shown in Table 4 below.

[0063]

[Table 4]

From the results shown in Table 4, by increasing the density of the core material for vacuum heat insulating material in advance, it is possible to reduce the rate of increase in the density after vacuuming, that is, the volume shrinkage due to vacuuming is reduced. It was confirmed that it can be done. Further, in the vacuum heat insulating material of the present invention, it was confirmed that the density of the core material before vacuum drawing was suppressed to 300 kg / m ³ or less and the density after vacuum drawing was suppressed to 400 kg / m ³ or less.

<Change in heat insulation performance with time> Regarding the vacuum heat insulation material of the present invention produced in the above Example 1 and the vacuum heat insulation material using the continuous urethane of Comparative Example 7, the heat insulation performance at the time of production and at 70 ° C. When the heat insulation performance after being left for 90 days was measured and compared, the vacuum heat insulation material of the present invention showed almost no deterioration in the heat insulation performance (heat conductivity was 5%, though the adsorbent was not used. Increased.). On the other hand, in the continuous urethane using the adsorbent, it was confirmed that the heat insulating performance was lower than that of the vacuum heat insulating material of the present invention (the thermal conductivity was increased by 100%).

[0066]

According to the present invention, an unreacted substance, a foaming agent,
Also, it does not contain impurities that cause outgas such as organic binders, has continuity, has excellent handleability and heat resistance, is easy to transport, and has excellent heat insulation performance. It is not necessary to enclose an adsorbent when the core material for a vacuum heat insulating material is housed in a container, the pressure resistance against atmospheric pressure is high when vacuuming is performed, the shape can be maintained, dust is not generated, and excellent heat insulation is achieved. It is possible to provide a vacuum heat insulating material that has performance, does not generate outgas, and does not deteriorate in heat insulating performance.

[Brief description of drawings]

FIG. 1 is an example of a sectional view of a main part of a vacuum heat insulating material according to the present invention.

FIG. 2 is an example of a fragmentary sectional view of a refrigerator using the vacuum heat insulating material of the present invention.

[Explanation of symbols]

10 Core material for vacuum insulation 16 Vacuum insulation 18 containers 21 refrigerator 22 Outer box 23 Insulation 24 inner box 25 insulated door 26 Vacuum insulation 27 Polyurethane foam

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hitoshi Hoshino             2-5-3 Keihan Hondori, Moriguchi City, Osaka Prefecture             Within Yo Denki Co., Ltd. (72) Inventor Hideaki Kamiya             2-5-3 Keihan Hondori, Moriguchi City, Osaka Prefecture             Within Yo Denki Co., Ltd. (72) Inventor Junichi Kubota             2-5-3 Keihan Hondori, Moriguchi City, Osaka Prefecture             Within Yo Denki Co., Ltd. F-term (reference) 3L102 JA01 JA02 JA03 JA07 MB23                       MB31                 4L047 AA05 AA14 AA17 AA21 AA23                       AA28 AB07 AB10 BA03 BA07                       BA08 BA24 CA02 CA19 CB06                       CB10 CC14

Claims (12)

[Claims] 1. A core material for a vacuum heat insulating material comprising glass wool and a thermoplastic resin fiber. 2. The vacuum heat insulating material according to claim 1, wherein the thermoplastic resin fiber is adhered to the glass wool by heating, melting and pressing while maintaining the communication between the glass wool and the thermoplastic resin fiber. Core material. 3. The average fiber diameter of the glass wool is 20 μm.
m or less, and the average fiber diameter of the thermoplastic resin fibers is 1
The core material for a vacuum heat insulating material according to claim 1 or 2, wherein the core material has a diameter of 00 µm or less and a content of the thermoplastic resin fiber is 1% by weight or more. 4. The average fiber diameter of the glass wool is 0.6.
The average fiber diameter of the thermoplastic resin fiber is 1 μm or more and 15 μm or less, and the content of the thermoplastic resin fiber is 10% by weight or more and 20% by weight or less. The core material for a vacuum heat insulating material according to any one of claims. 5. The melting point of the thermoplastic resin fiber is 250.
The core material for a vacuum heat insulating material according to any one of claims 1 to 4, which has a temperature of not higher than 0 ° C. 6. The core material for a vacuum heat insulating material according to claim 1, wherein the thermoplastic resin fiber contains at least one of polypropylene, acrylic, polyethylene terephthalate, polyamide and polyethylene. . 7. A step of mixing and opening the glass wool and the thermoplastic resin fiber to obtain a cotton-like mixture, a step of laminating the cotton-like mixture, and a needle punching process on the laminated cotton-like mixture. 7. The method according to any one of claims 1 to 6, wherein the mat is manufactured by a method for manufacturing a core material for a vacuum heat insulating material, which comprises a step of forming a mat by hot pressing, and a step of hot pressing the mat, and then cooling the mat for compression molding. Vacuum insulation core material. 8. In the step of forming a mat by subjecting the laminated cotton-like mixture to needle punching, the tip of the needle among the plurality of barbs provided in the needle used for the needle punching is used. 50% at the depth in the thickness direction of the laminated flocculent mixture without the provided barb penetrating the laminated flocculent mixture.
The core material for a vacuum heat insulating material according to claim 7, wherein the barb is fastened to a position of 90% or more and needle punching is performed. 9. The mat is hot pressed and then cooled.
In the process of compression molding by discarding
Topless is 0.1kg / cm on the mat ²More pressure
Apply pressure at a temperature of 90 ° C to 250 ° C.
The vacuum according to claim 7 or 8, which is performed by heating.
Core material for heat insulating material. 10. A density of 150 kg / m ³ or more 400
The core material for a vacuum heat insulating material according to any one of claims 1 to 9, which has a weight of not more than kg / m ³ . 11. A vacuum heat insulating material core material according to claim 1, and a container for accommodating the vacuum heat insulating material core material and capable of maintaining a vacuum inside. Vacuum insulation material to do. 12. A density of 150 kg / m ³ or more 400
The vacuum heat insulating material according to claim 11, which has a pressure of not more than kg / m ³ .