WO2016121372A1

WO2016121372A1 - Heat insulator and method for manufacturing heat insulator

Info

Publication number: WO2016121372A1
Application number: PCT/JP2016/000360
Authority: WO
Inventors: 孝太郎中西; 笑美子中西; 源植田
Original assignee: オゾンセーブ株式会社
Priority date: 2014-01-30
Filing date: 2016-01-25
Publication date: 2016-08-04
Also published as: JP6188245B2; TW201629184A; JP2015163815A; TWI619807B

Abstract

The present invention provides a heat insulator that is less bulky than in the related art, has excellent processability, and can be applied to a microstructure, and also provides a manufacturing method by which such a heat insulator can be manufactured. The heat insulator according to the present invention comprises a main fiber, xerogel and/or aerogel, at least one hydrosoluble polymer selected from the group consisting of a cationic polymer and an ampholytic polymer, and/or a binder including a low-melting-point synthetic fiber, and is characterized in that the xerogel and the aerogel have a density lower than 0.5 g/cm³ and a thermal conductivity of 0.02 W/(m·K) or lower and, in terms of the gross weight, 35-210 parts by weight of the xerogel and/or aerogel are combined with 100 parts by weight of the main fiber.

Description

Insulating material and method of manufacturing the insulating material

The present invention relates to a heat insulating material having a heat insulating property and a method for manufacturing the heat insulating material.

Refrigerated and frozen products such as pharmaceuticals and food products are usually corrugated cardboard with insulation such as foamed polystyrene containers and urethane foam that have heat insulation properties in environments other than refrigerated and frozen conditions to prevent quality deterioration during transportation. It is housed and transported in an insulated container (for example, Patent Document 1) such as a box. Since such a heat insulating container is bulky as compared with the product to be stored, there has been a problem that the transportation cost of the product is increased. In addition, it is essential to prepare an insulated container separately from the product itself, and to store and pack the product, which has been a factor in complicating the transportation procedure.

On the other hand, there are many occasions where a container that keeps the product at a high temperature for a relatively long time is required. Such a container is often required to be touched with a bare hand at the same time as the outside does not become hot at the time of use. As such a container, a bulky material container such as foamed polystyrene, a paper container having a laminated structure on the side wall, or the like is used in order to provide heat retention. As a paper container having a laminated structure on the side wall, for example, a paper container having an air layer inside the laminated side wall is known as in Patent Document 2. In any case, the whole is bulky as compared with the inner volume, and a large space is required for transporting and storing the container itself.

JP-A-11-147777 JP 2000-247377 A JP 7-48881 A

As described above, since most of the conventional heat insulating materials in each field are bulky, it has been a factor of lowering transportation efficiency and storage efficiency. In addition, the materials used are limited to glass wool, heat insulation board, foamed urethane, foamed polystyrene, etc., and due to their thickness and structural weakness, fine processing and molding are difficult, and box-shaped heat insulation containers Moreover, the object used, such as a comparatively large base material, was limited.

Therefore, an object of the present invention is to provide a heat insulating material that is less bulky than the prior art, has excellent workability, and can be applied to a fine structure, and a manufacturing method capable of manufacturing such a heat insulating material.

The heat-insulating material of the present invention that solves the above problems is at least one water-soluble polymer selected from the group consisting of a main fiber, xerogel and / or aerogel, a cationic polymer and an amphoteric polymer, and / or a low-melting-point synthesis. A xerogel and aerogel having a density of less than 0.5 g / cm ³ and a thermal conductivity of 0.02 W / (m · K) or less, wherein the main fiber The xerogel and / or airgel is blended in a total weight of 35 to 210 parts by weight with respect to 100 parts by weight.
The heat insulating material of the present invention having the above-described structure is low in volume like ordinary paper and has excellent workability, and in addition to a certain amount, xerogel and / or airgel with low density and low thermal conductivity. , Has excellent heat insulation. Further, the heat insulating material of the present invention includes at least one water-soluble polymer selected from the group consisting of a cationic polymer and an amphoteric polymer as a binder in addition to the main fiber, xerogel and / or aerogel, and / or low melting point synthesis. Contains fiber. By containing the binder, the particle shape of the xerogel and the airgel in the paper making process or the like is not easily broken, and the heat insulating property is easily maintained.
Here, the “density” refers to that measured in the state of particles at 25 ° C. and 1 atm. Further, the “xerogel” and “aerogel” referred to here are fine particles having a continuous matrix of a solid material having a large number of nanometer-scale pores from which air is dispersed. Furthermore, in the present invention, “parts by weight” is based on dry weight except for water.
The “low-melting-point synthetic fiber” as used herein means a synthetic fiber having a melting point lower than the melting point when the main fiber has a melting point at least 140 ° C. at least on the surface of the fiber. Shall point to.
Furthermore, the heat insulating material of the present invention contains xerogel and / or aerogel. For example, the physical properties (such as density and thermal conductivity) and the amount of compounding of xerogel and aerogel are defined in this book. When the heat insulating material of the invention contains both a xerogel and an airgel, both satisfy the provisions of the physical properties, and the total weight of both of them satisfies the provisions of the blending amount.

The binder preferably contains the water-soluble polymer, and the water-soluble polymer is preferably at least one of cationized starch and amphoteric starch. By using cationized starch or amphoteric starch as the binder, the particle shape of the xerogel and the airgel at the time of papermaking is more difficult to break, and the heat insulating performance of the heat insulating material using this can be maintained.
The binder preferably includes the low-melting synthetic fiber, and the low-melting synthetic fiber is a vinylon binder fiber. By using a vinylon binder fiber as a binder, a heat insulating material can be produced efficiently.

The xerogel and aerogel are preferably porous silica particles obtained by converting a methylsilicate monomer into a xerogel by atmospheric drying or aerogeling by critical drying. The normal pressure dried gel or critical dried gel of methyl silicate is easy to produce at low density, and since the porous shape does not easily collapse in an aqueous solution, the shape is easily retained in the papermaking slurry.

The xerogel and the airgel preferably have an average particle diameter of 2 to 140 μm and a specific surface area of 400 m ² / g or more. By setting the average particle size of xerogel and airgel to 2 to 140 μm, it is possible to give sufficient heat insulation to the heat insulating material and to exhibit heat insulating performance even in a low-volume heat insulating material. Moreover, it becomes possible to provide higher heat insulation to a heat insulating material by the specific surface area of porous silica activation being 400 m < ² > / g or more.

The heat insulating material of the present invention is preferably in the form of a sheet having a thickness of 15 μm to 1.2 cm, a basis weight of 5 to 480 g / m ² , and a density of 0.5 to 1.5 g / cm ³ . By making a heat insulating material into the said property, paper-like texture and workability can be given.

The method for producing a heat insulating material according to the present invention comprises a main fiber of 100 parts by weight, a density of less than 0.5 g / cm ³ , and a thermal conductivity of 35 to 210 weights in total weight of 0.02 W / (m · K) or less. A part of xerogel and / or aerogel, and at least one water-soluble polymer selected from the group consisting of a cationic polymer and an amphoteric polymer, and / or 0.3 to 125 parts by weight of a binder containing low melting point synthetic fibers, Is mixed with water to prepare a mixed slurry, and the mixed slurry is made into paper. According to the above production method, it is possible to produce a heat insulating material having an excellent heat insulating property in addition to having a low bulk as in ordinary paper and having excellent workability.

In the method for producing a heat insulating material of the present invention, the mixed slurry at the time of papermaking is preferably pH 7-8. In a slurry having a pH of 7 to 8, the characteristics and properties of xerogel and airgel are likely to be stable, and at the same time, when the main fiber contains pulp, fibrillation is likely to be promoted.

Also, in the method for producing a heat insulating material of the present invention, the binder of the mixed slurry contains the water-soluble polymer, and the water-soluble polymer and the xerogel and / or the airgel are at least the main fibers suspended in water. In addition, it is preferable to adjust the mixed slurry by addition and mixing. This is because the composite of xerogel and / or airgel and fiber is formed by entanglement of the xerogel and / or airgel with the fiber, and it is difficult to float on the water surface.

The heat insulating material of the present invention has sufficient heat insulating properties, is low in bulk, and has excellent workability. Moreover, the manufacturing method of the heat insulating material of this invention can provide the heat insulating material which was low in bulk and excellent in workability, maintaining sufficient heat insulation.

Hereinafter, the heat insulating material of the present invention and the method for producing the heat insulating material will be described as an example.

1. Heat insulating material The heat insulating material of the present invention includes a main fiber, xerogel and / or airgel, at least one water-soluble polymer selected from the group consisting of a cationic polymer and an amphoteric polymer, and / or a low melting point synthetic fiber. A xerogel and an airgel having a density of less than 0.5 g / cm ³ and a thermal conductivity of 0.02 W / (m · K) or less, and 100 parts by weight of the main fiber On the other hand, the xerogel and / or the airgel is blended in a total weight of 35 to 210 parts by weight. Hereafter, each compounding component of the said heat insulating material is explained in full detail.

<Main fiber>
As the main fiber of the heat insulating material of the present invention, either a synthetic fiber or a natural fiber can be used. When synthetic fibers are used, the main fibers are not particularly limited. For example, polyester fibers, vinylon fibers, olefin fibers, polyurethane fibers, aramid fibers, which are synthetic fibers that are usually used as raw materials for nonwoven fabrics. Acrylic fiber, polylactic acid fiber, polyvinyl chloride fiber, vinylidene fiber, polyphenylene sulfide fiber, ceramic fiber, alumina fiber, glass fiber can be used, polyester fiber is preferable, polyethylene terephthalate (hereinafter referred to as PET) fiber Is more preferable.
Moreover, when using a natural fiber, although it does not specifically limit as a main fiber, For example, a pulp can be used. The type of pulp is not particularly limited, and any of wood pulp, non-wood pulp, and deinked pulp, which are usually used as raw materials for paper, can be used. Chemical pulp, semi-chemical pulp, mechanical pulp Any pulp can be used.
The selection of various main fibers can be appropriately changed according to the desired flexibility, heat resistance, flame retardancy, non-flammability, flexibility, strength, and weight of the heat insulating material. Only one type of fiber can be contained, or a plurality of types of fibers can be contained.

In particular, in the heat insulating material of the present embodiment containing a large amount of xerogel and / or airgel, which will be described later, for example, when only the pulp is used as the main fiber, the strength tends to be low although it has high heat insulating properties. In this case, by mixing 0.5 to 22 parts by weight of microfibrillated pulp (cellulose nanofibers) in 100 parts by weight of all the main fibers in the main fiber, while maintaining the high heat insulating property of the heat insulating material. , Paper-like strength and workability can be imparted.
In a heat insulating material containing a large amount of xerogel and / or airgel, which will be described later, synthetic fibers having a small fiber diameter are desirable in order to retain the xerogel and the airgel.

<Xerogel, Aerogel>
The xerogel and aerogel used in the present invention are fine particles having a continuous matrix of solid material from which a large number of nanometer-scale pores are dispersed and from which air is dispersed. For example, 99% is composed of air and is very light. It becomes an effective heat insulating material. As the xerogel and airgel, known silica compounds such as silica, methyl silicate and silica / alumina, and porous particles such as resorcinol / formaldehyde, cellulose and cellulose nanofiber can be used. Regardless of the degree of porosity, the thermal conductivity of the material itself is 0.15 W / (m · K) or less, particularly 0.1 W / (m · K) or less, and further 0.06 to 0.018 W / ( m · K) is preferably used. In particular, methyl silicate monomer xerogel by atmospheric drying or airgel by critical drying can be easily manufactured at low density, and can easily form a porous structure or hollow structure at the nano level. It can be suitably used because it is difficult to disintegrate in an aqueous solution.

The porosity of xerogel and airgel is preferably 50.0 to 99.8%, particularly preferably 70 to 99.8%, and more preferably 86 to 99.8%. The average particle size is not particularly limited, but is preferably 2 to 140 μm. If the particle size of the xerogel and airgel of the porous silica particles is more than 140 μm, it is necessary to increase the thickness of the heat insulating material, and it is difficult to achieve the object of the present application to provide a heat insulating material agent having a low bulk and a heat insulating effect. Further, if it is less than 2 μm, it is difficult to obtain a sufficient heat insulating effect.

Xerogels and aerogels having a specific surface area of 400 m ² / g or more, preferably 500 to 1000 m ² / g, more preferably 600 to 1000 m ² / g, are preferably used. By increasing the specific surface area, the porosity can be increased. Moreover, the weight of the whole heat insulating material can also be reduced.

The amount of xerogel and / or aerogel in the heat insulating material of the present invention is preferably 35 to 210 parts by weight based on 100 parts by weight of the main fiber in terms of total weight. If the amount of xerogel and / or aerogel is less than 35 parts by weight in total weight, there is a possibility that sufficient heat insulating properties cannot be given to the heat insulating material. Moreover, when the total amount of xerogel and / or airgel exceeds 210 parts by weight, the strength of the heat insulating material decreases, and it becomes difficult to obtain the desired paper-like processability. Problems such as falling off, scattering, etc. may occur.
Further, when the main fiber contains pulp and the binder described later contains at least one water-soluble polymer selected from the group consisting of a cationic polymer and an amphoteric polymer, from the same point of view, compounding of xerogel and / or airgel The total amount is preferably 35 to 75 parts by weight, particularly 35 to 60 parts by weight, and more preferably 38 to 52 parts by weight based on 100 parts by weight of the main fiber.
Further, when the main fiber includes a synthetic fiber and the binder described later includes a low melting point synthetic fiber, from the same viewpoint as described above, the compounding amount of xerogel and / or aerogel is 100 parts by weight of the main fiber in terms of the total weight. The amount is preferably 100 to 210 parts by weight.
In the present embodiment, a heat insulating material having equivalent performance can be obtained when xerogel is contained and when airgel is contained.

<Binder>
The heat insulating material of the present invention contains at least one water-soluble polymer selected from the group consisting of a cationic polymer and an amphoteric polymer, and / or a binder containing low-melting synthetic fibers. That is, the binder contained in the heat insulating material of the present invention includes at least one water-soluble polymer selected from the group consisting of a cationic polymer and an amphoteric polymer, and / or a low melting point synthetic fiber. As the water-soluble polymer, those obtained by cationizing and / or amphotericizing starch, polyvinyl alcohol (PVA), polyvinyl acetate, aqueous urethane and the like can be preferably used. In particular, at least one of cationized starch and amphoteric starch can be used more suitably because bubbles are not easily generated in the aqueous solution during paper making, and stable paper making and high yield are possible.
The cationized starch and the amphoteric starch can be carried out by using known methods described in, for example, JP-A No. 2003-64101 (cationized starch), JP-A No. 2001-19701 (amphoteric starch) and the like. . In addition, what is marketed can use a cationic starch suitably, for example, Nippon Food Chemical Co., Ltd. Neotuck series etc. are applicable.
The “water-soluble polymer” includes a hydrocolloid in addition to a water-soluble polymer.

The low melting point synthetic fiber has a melting point of 140 ° C. or lower at least on the surface of the fiber, and is lower than the melting point when the main fiber has a melting point (for example, when the main fiber contains a synthetic fiber). It is not particularly limited as long as it is a synthetic fiber having a melting point, and as the low melting point synthetic fiber, for example, a vinylon binder fiber, an olefin binder fiber, a polyester binder fiber or the like can be suitably used.
As the low melting point synthetic fiber, a vinylon binder fiber is particularly preferable, and the fiber dissolves in water at 70 ° C., so that the xerogel and / or the airgel and the fiber can be bonded to each other at the time of drying. A commercially available vinylon binder fiber can be used as appropriate, and for example, VPB105-1 manufactured by Kuraray Co., Ltd. is applicable.
The binder fiber may be a core-sheath fiber whose core is a high melting point component and whose sheath is a low melting point component.

By using at least one water-soluble polymer selected from the group consisting of a cationic polymer and an amphoteric polymer and / or a low-melting synthetic fiber as a binder, by containing the binder, in a papermaking process, etc. The particle shape of the xerogel and the airgel is less likely to collapse, and the heat insulating property is easily maintained. In particular, when the main fiber contains pulp and the xerogel and / or aerogel is porous silica particles, more specifically methyl silicate particles, the pulp is usually anionic in a pulp slurry containing water and pulp. In addition, the porous silica particles, particularly methyl silicate particles, added to the slurry exhibit anionic or amphoteric properties. Anionic pulp and anionic or amphoteric porous silica particles are unlikely to aggregate with each other and the yield tends to be low. Here, by using a cationic polymer and / or an amphoteric polymer as a binder, it is possible to promote the aggregation of pulp and porous silica particles and to increase the yield.
The yield can be further increased by using a known flocculant containing chitin, chitosan and the like.

The binder is preferably blended in an amount of 0.3 to 125 parts by weight with respect to 100 parts by weight of the main fiber. When the blending amount of the binder is less than 0.3 parts by weight, the particle shape of the xerogel and the airgel in the paper making process or the like is unlikely to occur, and the heat insulating property is easily maintained. Moreover, when the compounding quantity of a binder exceeds 125 weight part, there exists a possibility that the intensity | strength of a heat insulating material may fall and it may become difficult to obtain desired paper-like processability.
When the main fiber contains pulp and the binder contains at least one water-soluble polymer selected from the group consisting of a cationic polymer and an amphoteric polymer, from the same viewpoint, the blending amount of the water-soluble polymer is The amount is preferably 0.3 to 33 parts by weight, more preferably 0.3 to 18 parts by weight, based on 100 parts by weight of the fiber.
Further, when the main fiber includes a synthetic fiber and the binder includes a low melting point synthetic fiber, the binder is preferably blended in an amount of 20 to 100 parts by weight with respect to 100 parts by weight of the main fiber. In such a case, the particle shape of the xerogel and the airgel in the paper making process or the like is less likely to be collapsed, and the heat insulating property is more easily maintained.
Further, when the main fiber includes a synthetic fiber and the binder includes a low melting point synthetic fiber, the amount of the binder is preferably 10 to 20 parts by weight with respect to 100 parts by weight of the airgel. In such a case, it is because the heat insulation of a heat insulating material can be ensured effectively.

<Other ingredients>
In addition, although not particularly limited, for example, a paper strength additive such as vegetable gum, aqueous cellulose derivative, sodium silicate, etc., which is usually used as an additive for papermaking, rosin, carboxymethyl cellulose, alkyl ketene dimer, alkenyl Add succinic anhydride and other sizing agents, yield improvers such as polyacrylamide and sodium silicate, paper-making adhesives such as polyacrylamide and polyethylene oxide, dyes, and pigments as necessary by internal addition or size press. be able to. In addition to the above, for example, as additives, a dispersant such as a water-soluble polyurethane resin (for example, manufactured by Yoshimura Yuka Co., Ltd., Texanol PE-10F, etc.), an antifoaming agent (for example, manufactured by Meisei Chemical Industries, Ltd.) , Formless P new, etc.) can be used.

<Properties of thermal insulation>
The heat insulating material composed of the above components can be a sheet having a thickness of 15 μm to 1.2 cm, a basis weight of 5 to 480 g / m ² , and a density of 0.5 to 1.5 g / cm ³ . These numerical values are within the same range as general paper, and it can be seen that the heat insulating agent of the present invention has the same appearance and texture as paper. The heat insulating material does not need to be only one layer of the papermaking sheet, and may have a multilayer structure in which a plurality of sheets are bonded with an adhesive or the like, and a resin layer such as polyethylene is provided on one or both sides of the sheet. A laminate structure may be used. Particularly, by adopting a laminate structure, it is possible to prevent the xerogel and the airgel from falling off the sheet, and it is possible to increase the strength and heat insulating properties of the entire heat insulating material. From the same viewpoint as described above, the thickness of the heat insulating material is more preferably 40 μm to 1.2 mm.
Further, it is more preferable that the thickness is 40 μm to 1.2 mm, and by making the thickness within this range, sufficient manufacturability, handleability, and workability are maintained while maintaining sufficient heat insulation performance. Can be expensive. Further, the present invention can be applied in a fine structure requiring heat insulation or in a region where space is limited. As a heat insulating material excellent in processability and adaptable to a curved portion, a heat insulating material manufactured by Aspen Co., Ltd. made of silica xerogel or silica airgel and fiber ("Cryogel (registered trademark)", "Pyrogel (registered trademark)") However, the heat insulating material becomes a sheet having a thickness of 5 mm or more, and cannot be applied in a fine structure or a portion where space is limited. In addition, as a heat insulating material that is ultra-thin, excellent in workability, and capable of dealing with a curved portion, there is a heat insulating material manufactured by Panasonic (“NASBIS (registered trademark)”) in which a silica xerogel is combined with a fiber. The thickness limit is about 0.1 mm due to the above properties. Therefore, conventionally, a heat insulating material having high heat insulating performance even in the thickness range and having high handleability and workability is desired for heat insulation in a fine structure or in a region where space is limited. On the other hand, the heat insulating material of this embodiment can solve this problem suitably.

<Method for manufacturing heat insulating material>
1. Preparation of papermaking slurry 100 parts by weight of the main fiber, 35 to 210 parts by weight of the above xerogel and / or airgel, and 0.3 to 125 parts by weight of the above binder were added to water and mixed to prepare a mixed slurry. A papermaking slurry (mixed slurry) is prepared.
In addition, when using what contains said water-soluble polymer as a binder, a water-soluble polymer and a xerogel and / or an airgel are added and mixed with the slurry which suspended the main fiber in water at least. It is preferable to adjust the papermaking slurry. Specifically, for example, when a porous silica particle is used as the main fiber, pulp, xerogel and / or aerogel, and the binder contains a water-soluble polymer, the slurry is obtained by suspending the pulp in water. It is preferable to prepare a papermaking slurry (mixed slurry) by adding and mixing silica particles and a binder.

When preparing the papermaking slurry, it is preferable to adjust the slurry by adding acid, alkali or the like as necessary so that the slurry has a pH of 7-8. In particular, when the xerogel and / or aerogel is a hydrophobized methyl silicate or the like, its chemical structure is most likely to be stable under the conditions of pH 7-8. Therefore, it is desirable to prepare a slurry under the above conditions in order to maintain the porous structure of the particles.

2. Papermaking process The papermaking slurry is made using a known papermaking machine usually used in paper production. The slit width, drum diameter, drum rotation speed, press pressure, dryer temperature and the like of the paper machine can be appropriately changed depending on the desired properties of the heat insulating material sheet.

3. Attached process About the papermaking sheet obtained by the above papermaking process, if necessary, a plurality of sheets may be laminated via an adhesive, and a lamination process is performed by providing a resin layer such as polyethylene on one or both sides. May be.

In addition, in this manufacturing method of a heat insulating material, it is preferable to use a wet papermaking method. The wet papermaking method is a production method in which fibers and the like are dispersed in water and then rolled up with a wire to form a sheet.
In this method for producing a heat insulating material, the main fiber, xerogel and / or aerogel, and a binder are dispersed in water to produce a heat insulating material having a thickness of 15 μm to 1.2 mm, more preferably 40 μm to It can be set to 1.2 mm.

<Thermal insulation method using thermal insulation>
About the heat insulating material of this invention, it is possible to show the heat insulation effect with respect to the target goods by means, such as packaging the target goods and sticking to the target goods. Here, the material of the target article is not particularly limited, and any material such as paper, plastic, plate material, and metal can be used. Its purpose of use can also be used for food and pharmaceutical containers and packaging materials, building materials, and the like.
Specifically, the heat insulating material of the present embodiment is used as a heat countermeasure part for electronic devices, for example, used together with a heat dissipation material, or as an energy saving part or a safety countermeasure product such as a molding device, a mold apparatus, a piping member, etc. It is used as a building material and its peripheral members (roofing sheet, underfloor material, wallpaper, shoji paper, roll screen), used as an interior member of automobiles and transport vehicles, and as a packaging material with heat insulation performance To use.

The heat insulating material of the present invention can also be used for an electronic device (for example, a mobile phone, a digital camera, etc.) having a heat generating component inside. Specifically, the heat insulating material of the present invention can be used, for example, in an electronic device including a substrate on which a heat generating component is mounted and a housing that houses the substrate. More specifically, in an electronic device, a heat-insulating sheet having the heat-insulating sheet of the present invention in the form of a sheet and a heat-conducting sheet (eg, a graphite sheet) having high heat conductivity, a heat-generating component, It can arrange | position through the adhesive layer etc. inside the housing | casing of the position which opposes. In such a case, a heat conductive sheet is disposed between the heat generating component and the heat insulating sheet, or a heat conductive sheet is disposed between the housing and the heat insulating sheet (a side away from the heat generating component with respect to the heat insulating sheet). And / or both.
By using a heat insulation sheet including a heat insulating sheet in this way, when a heat conductive sheet is arranged between the heat generating component and the heat insulating sheet, the heat generated from the heat generating component is firstly transferred to the high heat conductive sheet. It is possible to prevent the heat conduction sheet from spreading over the entire surface of the heat conductive sheet and to locally increase the temperature, and subsequently to prevent the diffused heat from being transmitted to the housing by the heat insulating sheet.
In addition, when a heat conductive sheet is arranged between the housing and the heat insulating sheet, the heat generated from the heat generating component is first prevented from being transmitted to the heat conductive sheet by the heat insulating sheet, and then from the heat insulating sheet. The slight heat that has been transmitted to the heat conductive sheet can be spread over the entire surface of the heat conductive sheet, and the temperature of the housing can be prevented from rising locally.
Therefore, even if the temperature rises locally due to the heat-generating component inside the housing, the temperature rise of the surface of the housing can be prevented.

As mentioned above, although embodiment of this invention was described, the heat insulating material of this invention is not limited to the said example, A change can be added suitably.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to the following Example at all.
In order to confirm the effect of the heat insulating material of the present invention, the following two experiments were conducted.

[Experiment 1]
<Creation of insulation>
1. Example 1: Thermal insulation material 300 mL of water was put in a 500 mL beaker, and 200 g of commercially available kenaf pulp, a critically dry hydrophobic gel powder of methyl silicate (average particle size 5 μm, specific surface area 750 m ² / g, Aerogel Enova manufactured by Cabot) 100g, 0.8g of cationic starch (Nippon Food Chemical Co., Ltd. # 40T) was added and stirred using a handy mixer at 10,000rpm until the whole became uniform to prepare a pulp slurry. .
Next, the pulp slurry is manually made using a papermaking screen (material: nylon), and dried at room temperature in a wire mesh shape, whereby a heat insulating material having a thickness of 0.2 mm and a basis weight of 200 g / m ² (heat insulation). Sheet) was obtained. In addition, the external appearance, the flexibility, etc. of the obtained heat insulation sheet were similar to a commercially available drawing paper.

2. Examples 2 to 5: Insulation Material Insulation sheets prepared by drying three, five, seven, and ten sheets before drying on a paper sheet made in the same manner as in Example 1 2, 3, 4, and 5.

3. Comparative Examples 1 to 5: Paper Commercially available drawing paper having a thickness of 0.2 mm and a basis weight of 210 g / m ² was used as a comparative control. The one using only one drawing paper was Comparative Example 1, and the three, five, seven, and ten sheets were used as Comparative Examples 2, 3, 4, and 5, respectively.

<Evaluation of thermal insulation performance>
Insulating sheets of Examples 1 to 5 and Comparative Examples 1 to 5 so as to cover the outer peripheral surface of a commercially available paper cup (9 oz, caliber 77 mm × height 91 mm, material: virgin pulp (outside), polyethylene (inside)) Each piece of paper was wrapped around. At that time, heat insulation sheet and paper do not use adhesive etc., wrap so that it adheres closely to the paper cup and does not overlap, and tape the outer surface with cellophane tape of 1cm width x about 5cm only at the boundary line Stopped.
In each of the paper cups, 250 mL of hot water at 95 ° C. was added, and immediately after the addition, the surface temperature of the sheet outside after 10 seconds, 20 seconds, and 30 seconds was measured. Table 1 shows the measurement results of the surface temperature.

As shown in Table 1, compared with plain paper (drawing paper) having the same thickness and basis weight, the heat insulating material (heat insulating sheet) of the present invention is less likely to pass the temperature of hot water inside the paper cup through the outer surface. It was found that the insulation performance was excellent.

[Experiment 2]
<Creation of insulation>
1. Example 6: Heat insulation material 700 mL of water was put into a 1 L handy mixer, and 3.5 g of a commercially available polyester fiber (PET fiber, TA04PN SD 0.1 dtex x 3 mm) manufactured by Teijin Ltd. was put there at a rotational speed of 10,000 rpm. Stir until is uniform. To this, 1.2 g of vinylon binder fiber (VPB105-1 x 3 mm manufactured by Kuraray Co., Ltd.) was added and stirred. To this slurry, 7.0 g of a critically dry hydrophobic gel powder of methyl silicate (average particle size 90 μm, specific surface area 750 m ² / g, Aerogel Enova manufactured by Cabot) was added and stirred in the same manner to prepare a papermaking slurry.
Next, paper is made in the same manner as in Example 1, and dried with a rotary dryer to obtain a heat insulating material (heat insulating sheet) having a thickness of 0.25 mm and a basis weight of 100 g / m ^2. Was used as Example 6 (the thickness of the heat insulating material of Example 6 was 0.5 mm). In addition, the external appearance, the flexibility, etc. of the obtained heat insulation sheet were similar to a commercially available nonwoven fabric.

2. Examples 7 to 9: Insulating materials The insulating materials produced by the same method as in Example 6 were used by superimposing four, six and eight sheets, respectively, which were designated as Examples 7, 8, and 9 (Examples respectively) The thickness of the insulation material is 1.0 mm, 1.5 mm, and 2.0 mm).

3. Comparative Examples 6 to 9: Nonwoven fabric As a comparative control, 0.25 mm nonwoven fabric (polyester fiber (TA04PN SD 0.1 dtex x 3 mm manufactured by Teijin Ltd.) 100 parts by weight, vinylon binder fiber (VPB105-1 x 3 mm manufactured by Kuraray Co., Ltd.) 3 parts by weight) was used. A comparative example 6 was obtained by using only two non-woven fabrics, and comparative examples 7, 8, and 9 were obtained by superposing four sheets, six sheets, and eight sheets, respectively.

4). Example 10: Heat insulation material 700 mL of water was put into a 1 L handy mixer, and 3.5 g of commercially available polyester fiber (PET fiber, TA04PN SD 0.1 dtex x 3 mm) manufactured by Teijin Ltd. was put there at a rotation speed of 10,000 rpm. Was stirred until. To this, 1.2 g of polyester binder fiber (PET binder fiber, TK08PN SD 0.2 dtex x 3 mm, manufactured by Teijin Ltd.) was added and stirred. Furthermore, 3.1 g of cationic starch (Nippon Food Chemical Co., Ltd. # 40T), 7.0 g of methyl silicate critical dry hydrophobic gel powder (average particle size 90 μm, specific surface area 750 m ² / g, Cabot Aerogel Enova) In addition, stirring was similarly performed to prepare a papermaking slurry.
Next, paper is made in the same manner as in Example 1, and dried with a rotary dryer to obtain a heat insulating material (heat insulating sheet) having a thickness of 0.25 mm and a basis weight of 130 g / m ^2. Was used as Example 10 (the thickness of the heat insulating material of Example 10 was 0.5 mm). In addition, the external appearance, the flexibility, etc. of the obtained heat insulation sheet were similar to a commercially available nonwoven fabric.

5. Examples 11 to 13: Heat insulating materials Heat insulating materials manufactured by the same method as in Example 10 were used as four, six, and eight sheets, and were used as Examples 11, 12, and 13, respectively (Examples respectively) The thickness of the insulation material is 1.0 mm, 1.5 mm, and 2.0 mm).

6). Comparative Examples 10 to 13: Nonwoven fabric As a comparative control, 0.25 mm nonwoven fabric (polyester fiber (TA04PN SD 0.1 dtex x 3 mm) manufactured by Teijin Ltd.), polyester binder fiber (PET binder fiber, Teijin Ltd. TK08PN SD 0.2 dtex x) 3 mm) 33 parts by weight and cationic starch (Nippon Food Chemical Co., Ltd. # 40T) 36 parts by weight) were used. A comparative example 10 was obtained by using only two non-woven fabrics, and comparative examples 11, 12, and 13 were used by superimposing four, six and eight sheets, respectively.

<Evaluation of thermal insulation performance>
The heat insulating sheets (40 mm × 40 mm) of Examples 6 to 13 and the nonwoven fabrics (40 mm × 40 mm) of Comparative Examples 6 to 13 are placed on a stainless steel column (diameter: 47 mm, height: 57 mm) heated to about 100 ° C. placed. The surface temperature of the upper surface side of the sheet and nonwoven fabric after 10 seconds, 20 seconds, 30 seconds, and 60 seconds (the side opposite to the side where the sheet and nonwoven fabric contact with the cylinder) was measured. Table 2 shows the measurement results of the surface temperature.

As shown in Table 2, it was found that the heat insulating material (heat insulating sheet) of the present invention is less likely to pass through the temperature of a stainless steel cylinder and has excellent heat insulating performance as compared with a nonwoven fabric having an equivalent thickness.

Claims

A heat insulating material comprising a main fiber, a xerogel and / or an airgel, at least one water-soluble polymer selected from the group consisting of a cationic polymer and an amphoteric polymer, and / or a binder containing a low-melting synthetic fiber. And
The xerogel and the airgel have a density of less than 0.5 g / cm 3 and a thermal conductivity of 0.02 W / (m · K) or less, and the xerogel and / or the airgel is contained in 100 parts by weight of the main fiber. A heat insulating material characterized by containing 35 to 210 parts by weight in total weight.
The binder includes the water-soluble polymer,
The heat insulating material according to claim 1, wherein the water-soluble polymer is at least one of cationized starch and amphoteric starch.
The binder includes the low melting point synthetic fiber,
The heat insulating material according to claim 1, wherein the low melting point synthetic fiber is a vinylon binder fiber.
The heat insulating material according to any one of claims 1 to 3, wherein the xerogel and the airgel are porous silica particles obtained by converting a methyl silicate monomer into a xerogel by atmospheric pressure drying or aerogeling by critical drying.
The heat insulating material according to any one of claims 1 to 4, wherein the xerogel and the airgel have an average particle diameter of 2 to 140 µm and a specific surface area of 400 m 2 / g or more.
6. The heat insulating material according to claim 1, wherein the heat insulating material is in the form of a sheet having a thickness of 15 μm to 1.2 cm, a basis weight of 5 to 480 g / m 2 , and a density of 0.5 to 1.5 g / cm 3 .
100 parts by weight of the main fiber, 35 to 210 parts by weight of xerogel and / or airgel with a total weight of less than 0.5 g / cm 3 and a thermal conductivity of 0.02 W / (m · K) or less, and a cation At least one water-soluble polymer selected from the group consisting of a water-soluble polymer and an amphoteric polymer, and / or 0.3 to 125 parts by weight of a binder containing a low-melting-point synthetic fiber are added to water and mixed to form a mixed slurry. Prepared,
A method for producing a heat insulating material, wherein the mixed slurry is paper-made.
The method for manufacturing a heat insulating material according to claim 7, wherein the mixed slurry at the time of papermaking is adjusted to pH 7-8.
The binder of the mixed slurry comprises the water-soluble polymer;
The method for producing a heat insulating material according to claim 7 or 8, wherein the mixed slurry is prepared by adding and mixing the water-soluble polymer and the xerogel and / or aerogel to a slurry in which at least the main fiber is suspended in water. .