JP2002333092A - Fiber and fine particle composite heat-insulating material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve problems that conventional fibrous heat insulating materials are inferior in heat insulating performance, and excessively thickened in application, so that low heat conductivity is desired, on the other hand, a porous heat insulating material having high heat-insulating performance is inferior in productivity, handling and workability. SOLUTION: Fine particles are added and held in a space of a fibrous structural body formed by interlacing and/or adhering fiber, for example, bulky non-woven fabric having softness and rigidity, whereby the fiber and fine particle composite heat insulating material superior in heat-insulating property and workability can be provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fiber / fine particle composite heat insulating material which is excellent in heat insulation and workability and is most suitable for, for example, building materials.

[0002]

2. Description of the Related Art Conventionally, glass wool is used as a fiber-based heat insulating material used for houses. Glass wool has been favorably used because it is inexpensive, has excellent cushioning properties, and is easy to construct. On the other hand, energy conservation has been promoted as a global policy in order to prevent global warming, which has been a problem in recent years. I have. For example, by adapting to the "Standards of Construction Owner's Judgment Regarding Rationalization of Energy Use Related to Houses" and "Guidelines for Design and Construction" (commonly called "Next-generation Energy Conservation Standards") issued in March 1999. However, when glass wool is used for the roof, ceiling, or wall, the insulation performance is poor (exceeding 0.034 W / mK in terms of thermal conductivity), resulting in excessive thickness, poor fit, and difficulty in construction. is there. In particular, when applying to wall parts in the next-generation energy conservation standard I area, the required heat insulation thickness is 100 mm.
It will be thicker than that.

Recently, Japanese Patent Application Laid-Open No.
A sound-absorbing fiber molded article composed of a polyester resin fiber and a heat-sealing fiber as disclosed in JP-A-00-96497 has been put on the market, and there is one having good touch feeling, rigidity and heat insulation. However, since the performance of this fiber molded body as a heat insulating material is about glass wool, the thickness becomes excessively large, and it is difficult to perform the construction.

On the other hand, as porous heat insulating materials having a high heat insulating performance, there are a vacuum heat insulating material, an airgel heat insulating material, a microporous heat insulating material, etc., in which conduction heat transfer by gas is suppressed. Of these, when vacuum insulation is used as insulation for building materials, only a few pinholes are generated and the insulation effect exhibited by vacuum is lost, making it difficult to handle and process at construction sites. In addition, there is a problem in that the production involves a vacuum process and the production efficiency is poor. In addition, airgel heat insulating materials and microporous heat insulating materials exhibit very good heat insulating properties even without vacuum because they are made up of fine voids, but are brittle and difficult to handle. Its brittleness, formability, rigidity,
In order to improve the heat insulating property, for example, as a heat insulating material for aerogel, JP-A-1-199095 and JP-A-1-15
7473, a method of integrating with a honeycomb structure, a method of adding a small amount of fiber, and a method of integrating a non-woven fabric and a sol as described in JP-A-8-34678.

[0005] However, even these methods require a supercritical drying step, resulting in poor productivity, and still remain brittle and difficult to handle. On the other hand, as a microporous heat insulating material, there is a heat insulating panel disclosed in JP-A-9-217890. The content of the invention disclosed in this publication is based on the fact that a material in which fine particles are packed in a gas permeable sealing body (for example, a gas permeable non-woven fabric) is compression-molded, and the material obtained by compacting the fine particles is used as a main structure to provide heat insulation and molding. This is an invention that has improved properties and brittleness. However, since the main structure is formed by compacting fine particles, there is still a problem that the particles are brittle and easily broken.

[0006]

As described above, conventionally used fiber-based heat insulating materials are inferior in heat insulating performance and become excessively thick at the time of construction. Therefore, it is desired to reduce the thermal conductivity.
The vacuum heat insulating material, the airgel heat insulating material, and the microporous heat insulating material having high heat insulating performance have the above-mentioned problem that their handling and workability are poor.

The present invention has been made in view of the above-mentioned problems. More specifically, a fibrous structure, for example, a nonwoven fabric which is bulky, excellent in flexibility and strength, is mainly used as a main structure, and fine particles are added and included to provide heat insulation. Excellent workability and workability,
An object of the present invention is to provide a fiber / fine particle composite heat insulating material which can solve the disadvantages of being brittle and easily broken and can be easily manufactured.

[0008]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, have reached the present invention.

That is, according to the present invention, (1) a fiber having a bulk density of 0.01 g / cm ^{3 formed} by entanglement and / or adhesion of fibers;
The present invention relates to a fiber / particle composite heat insulating material in which 1 to 250 parts by weight of fine particles having an average particle diameter of 1 μm or less are held by the fiber structure in a space of 100 parts by weight of the fiber structure.

[0010] The present invention also relates to (2) the fiber / particle composite heat insulating material according to (1), wherein the fibrous structure is a nonwoven fabric.

Further, the present invention provides (3) one or more fine particles selected from inorganic fine particles such as silicon oxide, titanium oxide and carbon black and / or polymer fine particles such as polyvinyl chloride resin fine particles and acrylic resin fine particles. (1) or (2).

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The fiber / fine particle composite heat insulating material of the present invention will be described below.

The fibrous structure used in the present invention is not limited, and a non-woven fabric or a woven fabric can be used. Since a bulky and three-dimensional structure is easily obtained and a three-dimensional strength against compression and bending is easily obtained, a nonwoven fabric is preferably used. The nonwoven fabric used is a short fiber nonwoven fabric obtained by forming short fibers into a web by a known technique such as a card method or an air lay method, entangled by a needle punch method, or by mixing and heating and forming an adhesive component. It is possible to use those obtained by directly converting long fibers into a nonwoven fabric by a method such as a spun bond method, a melt blow method, or a flash spinning method.

When a non-woven fabric is prepared from short fibers, it is preferable that the non-woven fabric is crimped so that the bulk density can be easily adjusted.
By being crimped, the fibers become easily entangled with each other, and by further bonding, the entanglement becomes strong,
Bulkness and appropriate rigidity can be provided. The use of crimped short fibers is also preferred in that the elasticity against compression is improved.

The cross-sectional structure of the fiber used in the present invention may be a fiber having a circular cross section, a flat cross section, a hollow cross section, a polygonal cross section, or a core-sheath cross section. The fibers having a modified cross section are bulky and easy to obtain a three-dimensional structure, and the chance of reflecting radiant heat transfer in heat transfer is increased, and the heat insulating property is slightly improved.

The fineness of the fibers used in the present invention is not particularly limited as long as the fiber structure can be formed.
2 denier to 50 denier is preferably used. When converting the fineness into the average diameter of the fiber, the following formula is used.

Average diameter (μm) = 11.91 × (d / ρ) ^1/2 (d is fineness, ρ is specific gravity) As a material of the fiber structure used in the present invention, a polyolefin-based material such as polypropylene or polyethylene is used. Uses resins, polyester resins such as polyethylene terephthalate and polybutylene terephthalate, polyamide resins, polyvinyl chloride resins, acrylic resins, polyurethane resins, etc., as well as semi-synthetic fibers such as rayon and natural fibers such as animal hair. And their copolymers and the like can also be used. These organic fibers may be subjected to a flame retarding treatment as necessary. The fibers used are not limited to organic fibers, and glass fibers, glass wool, rock fibers, rock wool, alumina fibers, carbon fibers, and the like can also be used. Needless to say, fibers other than those exemplified above can be arbitrarily used as long as they can be formed into a nonwoven fabric. Even if the fibers that make up the nonwoven fabric are made of a single material, use a mixture of multiple materials for the purpose of achieving a good balance of performance such as strength, density, adhesion between fibers, touch, and flame retardancy. May be.

The thickness of the fibrous structure is not limited as long as it has a thermal conductivity value superior to that of the conventional fibrous heat insulating material and can be suitably used. It is preferable because workability such as cutting and the like is easy and it fits well in a heat insulating construction site.

The bulk density of the fiber structure is preferably 0.01 g / cm ³ or more as a whole and less than the density of the raw material used for the fibers. Here, the bulk density of the fiber structure was determined by the fiber structure bulk density (g / cm ³ ) = fiber structure weight (g) / fiber structure apparent volume (cm ³ ). The weight of the fiber structure includes the weight of the adhesive component constituting the fiber structure. The apparent volume indicates the space occupied by the fibrous structure, and if the fibrous structure has an apparent rectangular parallelepiped shape, the fibrous structure apparent volume (cm ³ ) = height (cm) × length (cm) × width (cm )
Becomes

The term "as a whole fibrous structure" means that there is a local density difference inside the fibrous structure. For example, the fibrous structure has a high density and a low density inside, The part means that a structure having a low density and a high density inside, a density gradually changing in a thickness direction, and a structure in which a high density layer and a low density layer are stacked are regarded as one structure. When the bulk density of the fibrous structure is lower than 0.01 g / cm ³ , the rigidity of the fibrous structure is low, so that it is difficult to handle. In addition, since the heat insulating performance of the fibrous structure is inferior, fine particles are excessively added. The necessity arises and it becomes difficult to retain the fine particles. The fact that the bulk density of the fibrous structure is equal to or higher than the density of the material used for the fibers means that there is substantially no void that holds the fine particles.

In the present invention, the average particle size of 1
It is characterized in that fine particles having a particle size of μ or less are present and held so as not to leak out of the fiber structure. Here, the “average particle diameter” is an arithmetic average particle diameter obtained by measuring the diameter of each particle in the electron microscope image by circular approximation. The "holding" state is a state in which fine particles are present in a space having an apparent volume occupied by the fibrous structure, that is, a state in which the fine particles are included between fibers in a mesh shape and adhere or float on the fiber surface. Means a state. Therefore, when the fine particles are surrounded or included in the bag structure instead of being covered by the bag body as in the prior art (hereinafter, sometimes referred to as inclusion instead of holding), the density of the fine particles is determined by a sandwich. It is preferable to densify in the vertical direction or the periphery partially or entirely as described above, or to cover the upper and lower surfaces of such a fibrous structure with a fibrous body such as a sheet. This eliminates the necessity of accommodating the fine particles in the bag body and solidifying and blocking the fine particles as in the known technique.

As the fine particles suitably used in the present invention,
Inorganic fine particles such as carbon black, titanium oxide, silicon oxide, calcium carbonate, talc, and kaolin, and polymer fine particles, for example, submicron particles obtained by combining soap-free emulsion polymerization, nonaqueous dispersion polymerization, miniemulsion polymerization and seed polymerization. There are polyvinyl chloride resin fine particles and acrylic resin fine particles of different diameters. In addition, there are airgel obtained by a supercritical drying method from a sol-gel method, and a fine porous body. However, the fine particles are not limited to these. Fine particles preferably used have an average particle diameter of 1 μm.
Or less, preferably 500 nm or less, more preferably 100 nm or less.
Such fine particles have a large solid-state heat transfer resistance due to point contact between the particles and a small gap between the particles, thereby suppressing convective heat transfer of air. Further, since many voids are generated which are smaller than the mean free path of the gas molecules constituting the air, the heat transfer due to the motion of the gas molecules is suppressed and the heat insulating property is greatly enhanced.

Since these fine particles are easily aggregated by moisture in the air, it is preferable to perform a hydrophobic treatment. The hydrophobizing agent is not particularly limited, but includes, for example, silane compounds such as alkyl silanes and fluorinated alkyl silanes, silicone compounds, amphiphilic substances such as fatty acids, and the like. Can be used as appropriate.

The inclusion form of the fine particles used in the present invention is as follows:
To reduce the thermal conductivity of the fiber structure to a desired value,
It is not limited as long as it is a form that can be easily held uniformly in the fibrous structure, and may be used as it is in a powder form. It can be used in the form of pellets, flakes, sheets, or blocks.

The amount of the fine particles added to the fiber structure is as follows.
1 part by weight to 250 parts by weight, preferably 5 to 200 parts by weight, more preferably 10 parts by weight based on 100 parts by weight of the fibrous structure.
１５０150 parts by weight. When the addition amount is less than 1 part by weight,
The effect of lowering the thermal conductivity due to the fine voids is small, and the heat insulating property is poor. If the amount exceeds 250 parts by weight, it becomes difficult to retain the fine particles in the fibrous structure.

It is preferable that the fiber structure of the present invention is locally or entirely densified so that the fine particles do not easily leak out of the structure. Since the fine particles used in the present invention are included in the fiber structure, they do not easily leak to the outside between molecules with the fiber, but there is a possibility that the fine particles may leak into the air when handled roughly. For this reason, it is preferable that the portion of the fibrous structure containing the fine particles is densified to prevent the fine particles from leaking. There is a method of rapidly heating and melting only the surface of the fiber structure to reduce air permeability, or a method of laminating a fiber structure or waterproof film with low air permeability on the outermost layer. Any method may be used.

In the method for producing the fiber / fine particle composite heat insulating material of the present invention, for example, a web obtained by short fibers is laminated on a plane to a uniform thickness, and then the fine particles are evenly dispersed, and then further spread thereon. A method of obtaining a fiber / fine particle composite heat insulating material by entanglement with a needle punch after laminating a web, a method of mixing and bonding an adhesive fiber as necessary to the above method, and a method of mixing short fibers and fine particles with a blender or the like in advance. After mixing and adhering to the fiber surface, the fine particles are included in the fiber structure by a method of processing the fibers into a structure, a method of including a thin non-woven fabric composed of long fibers in a multi-layer stack, or the like. The method may be a combination of the above methods, and the method is not particularly limited as long as the structure described in the claims is obtained.

[0028]

Next, the fiber / fine particle composite heat insulating material of the present invention will be described in more detail with reference to Examples. However, the present invention is not limited to only these Examples.

The properties of the fiber / fine particle composite heat insulating material obtained by the methods of Examples 1 to 6 and Comparative Examples 1 to 5 shown below are as follows.
The fiber structure bulk density, thermal conductivity, and required heat insulation thickness were examined according to the following methods.

1) Fiber structure bulk density (g / cm ³ ): The density is represented by the following formula: fiber structure bulk density (g / cm ³ ) = fiber structure weight (g) / fiber structure apparent volume (cm) ³ ) The weight of the fiber structure includes the weight of the adhesive component. Since the fibrous structure has an apparent rectangular parallelepiped shape,
Fiber structure apparent volume (cm ³ ) = height (cm) x length (cm) x width
(cm).

2) Thermal conductivity (W / mK): JIS A
The thermal conductivity was measured using a thermal conductivity measuring device HC-072 (manufactured by Eiko Seiki Co., Ltd.) in accordance with 9511.

3) In the areas II to V of the next-generation energy saving standards (extremely cold areas in Japan and areas excluding Okinawa), it is required when applying heat insulating material to the wall portion of a wooden house by the heat insulating method. The thickness of the heat insulating material for obtaining the thermal resistance was calculated from the thermal conductivity measured in 2). The required thickness of the heat insulating material was T, and the evaluation was made according to the following criteria. T ≦ 65 mm: ○ 65 mm <T ≦ 75 mm: Δ75 mm <T: × Further, the same calculation was performed for the region I, and the required thickness of the heat insulating material was set to t, and evaluated according to the following criteria. t ≦ 100 mm: 100 mm <t: × The evaluation results of the heat insulating materials obtained in the following Examples are shown in Table 1.

Example 1 Modacrylic short fiber (manufactured by Kaneka Chemical Industry Co., Ltd., trade name: Kanecaron, fiber diameter 13 μ, fiber length 30 mm) 90 parts by weight of hot melt nonwoven fabric (manufactured by Kureha Tech Co., Ltd.) Name: Dynac sheet LNS3000, melting temperature 90
C.) was added and mixed by a blender. Then, the mixed fibers were uniformly laminated on a flat surface, needle-punched, and the fibers were entangled with each other.
Then, after performing a heat treatment at a temperature of 120 ° C. for 30 seconds in a hot air oven, the fiber structure was obtained by air cooling.

FIG. 1A schematically shows an example of the obtained fiber structure. The obtained fiber structure had a thickness of 15 mm and an apparent density of 0.05 g / cm ³ . Two fiber structures were prepared in the same manner. Hydrophobic silicon oxide fine particles having a particle size of 15 nm (manufactured by Nippon Aerosil Co., Ltd., trade name: AEROSIL-R202) are placed on the upper surface of one of the fiber structures.
40 parts by weight to 100 parts by weight, and after one other fibrous structure was laminated, heat treatment was performed for 30 seconds in a hot air oven at 120 ° C. for 30 seconds to apply pressure, whereby fine particles were formed between the two fibrous structures. Were integrated.

In this way, the thickness of the fiber structure is 25 mm, the density of the fiber structure alone is 0.06 g / cm ³ ,
A fiber / fine particle composite heat insulating material containing 0 parts by weight of silicon oxide fine particles was obtained. FIG. 2 schematically shows the fiber / fine particle composite heat insulating material obtained in this manner. 1 is a fiber / particle composite heat insulating material of the present invention,
(A) is a fiber structure, (b) is a fine particle layer, (c) is fine particles, and (d) is a fiber.

When the thermal conductivity of this fiber / fine particle composite heat insulating material was measured, it was 0.0276 W / mK, which was a very excellent thermal conductivity. When this heat insulating material is applied to the wall part in the II-V area, the required thickness is 61 mm, and when it is applied to the I area,
It was 92 mm thin and flexible, and construction was easy.

Example 2 The same hot melt nonwoven fabric as in Example 1 was used for 80 parts by weight of modacrylic staple (Kanekalon Chemical Industry Co., Ltd., trade name: Kanecaron, fiber diameter 18 μm, fiber length 38 mm). After adding 20 parts by weight of the flaked product and mixing with a blender, the mixed fibers were uniformly laminated on a plane so as to have a thickness twice as large as that of the example, needle-punched, and the fibers were entangled with each other. . Then, after performing a heat treatment at a temperature of 120 ° C. for 30 seconds in a hot air oven, the fiber structure was obtained by air cooling. The obtained fiber structure had a thickness of 30 mm and an apparent density of 0.03 g / cm ³ . 150 parts by weight of the same hydrophobic silicon oxide fine particles as in Example 1 were simultaneously charged into the drum type rotating body with respect to 100 parts by weight of the fiber structure and 100 parts by weight of the fiber structure, so that the silicon oxide was included in the fiber structure.

FIG. 3 schematically shows a mixture of the fiber structure and the fine particles thus obtained, as shown in FIG. 3, in which the fine particles are uniformly dispersed in the fiber structure. The mixture of the fiber structure and the fine particles was taken out, and the weight was measured. As a result, the amount of silicon oxide substantially contained in the fiber structure was 85 parts by weight. Even in this state, it can be used as a fiber / particle composite heat insulating material.

Furthermore, in order to prevent leakage of fine particles, a moisture-permeable waterproof sheet (manufactured by Asahi DuPont Flash Spun Products Co., Ltd., product name: Tyvek) is provided on the upper and lower surfaces of the fiber structure containing silicon oxide via hot melt nonwoven fabric. ) Were heated and pressed to obtain a fiber / fine particle composite heat insulating material. FIG. 4 shows a schematic example of the obtained fiber / particle composite heat insulating material. FIG. 4E shows a waterproof sheet having a structure for preventing leakage of fine particles. In the fiber-particle composite insulation thickness 25 mm, an apparent density of 0.036 g / cm ³ of only fibrous structure comprises silicon oxide particles of 85 parts by weight relative to the fiber structure, dense layer on its surface Yes, fibers and particles in which fibers and particles are evenly mixed
It became a fine particle composite insulation material.

When the thermal conductivity of this fiber / fine particle composite heat insulating material was measured, it was 0.0270 W / mK, which was a very excellent thermal conductivity. When this insulation material is applied to the wall area in the II-V area, the required thickness is 60 mm, and when it is applied to the I area,
It was as thin as 90 mm, flexible and easy to construct.

Example 3 Instead of silicon oxide, hydrophobic titanium oxide having a particle diameter of 15 nm (manufactured by Teica Co., Ltd., trade name: SMT-150IB)
A fiber / fine particle composite heat insulating material was obtained under the same conditions as in Example 1 except for using. Table 1 shows the properties of the obtained heat insulating material. As compared with Comparative Examples 1 to 7 described below, a heat insulating material having significantly improved heat insulating properties was obtained.

Example 4 Fibers and fibers were prepared under the same conditions as in Example 1 except that 50 parts of carbon black having a particle diameter of 24 nm (trade name: # 40, manufactured by Mitsubishi Chemical Corporation) was used instead of silicon oxide. A fine particle composite heat insulating material was obtained. Table 1 shows the properties of the obtained heat insulating material.
As compared with Comparative Examples 1 to 7 described below, a heat insulating material having significantly improved heat insulating properties was obtained.

Example 5 Instead of silicon oxide, fine acrylic resin particles having a particle diameter of 400 nm (Soken Chemical Co., Ltd., trade name: MP-1000)
Was obtained under the same conditions as in Example 1 except that 30 parts of was used. Table 1 shows the properties of the obtained heat insulating material. As compared with Comparative Examples 1 to 7 described below, a heat insulating material having significantly improved heat insulating properties was obtained.

Example 6 The apparent density of the final fiber structure is 0.1 g / cm.
^{In 3} , the silicon oxide was 9 parts per 100 parts by weight of the fiber structure.
Except for containing 7 parts by weight, the fibers and
A fine particle composite heat insulating material was obtained. Table 1 shows the properties of the obtained heat insulating material.
Shown in As compared with Comparative Examples 1 to 7 described below, a heat insulating material having significantly improved heat insulating properties was obtained.

[0045] Except for not adding the Comparative Example 1 silicon oxide to obtain a fiber-based insulation density 0.06 g / cm ³ apparent in the same manner as in Example 1. Table 1 shows the properties of the obtained heat insulating material. The heat insulation was inferior to those of the examples, and the thickness required for heat insulation was thick.

Comparative Example 2 The bulk density of the fiber structure was 0.06 g / cm ^{3 in} the same manner as in Example 1 except that 0.5 parts by weight of silicon oxide was added.
A fiber / fine particle composite heat insulating material was obtained. Table 1 shows the properties of the obtained heat insulating material. The heat insulation was inferior to those of the examples, and the thickness required for heat insulation was thick.

Comparative Example 3 A bulk density of 0.03 g / cm ^{3 was obtained in} the same manner as in Example 2.
Tried to add 300 parts by weight of silicon oxide to the fibrous structure, but the shape could not be maintained by the fibrous structure,
Fiber / fine particle composite insulation could not be obtained.

Comparative Example 4 A bulk density of 0.005 g / cm was obtained in the same manner as in Example 2.
^When 20 parts by weight of silicon oxide was added to the fibrous structure of No. ³ , the heat insulating property was poor.

Comparative Example 5 A bulk density of 0.005 g / cm was obtained in the same manner as in Example 2.
^An attempt was made to add 80 parts by weight of silicon oxide to the fibrous structure of No. ³ , but the fibrous structure could not contain silicon oxide.

Comparative Example 6 A fibrous structure was prepared in the same manner as in Example 1 except that 20 parts by weight of calcium carbonate having a particle diameter of 2.2 μm (Softon 1000, manufactured by Bihoku Powder Chemical Industry Co., Ltd.) was added. A fiber / fine particle composite heat insulating material having a bulk density of 0.06 g / cm ³ was obtained.
Table 1 shows the properties of the obtained heat insulating material. The heat insulation was inferior to those of the examples, and the thickness required for heat insulation was thick.

Comparative Example 7 The thermal conductivity of the glass wool heat insulating material of 0.080 g / cm 3 was 0.0344 W / mk.

[0052]

[Table 1]

[0053]

According to the fiber / fine particle composite heat insulating material of the present invention, a heat insulating material for a house which is excellent in heat insulating performance, excellent in workability and easy to handle can be obtained.

[Brief description of the drawings]

FIG. 1 shows a perspective view of an example of a fiber structure according to the present invention.

FIG. 2 is a perspective view of a fiber / fine particle composite heat insulating material in which fine particles are contained between fiber structure layers.

FIG. 3 is a perspective view of an example of a fiber / particle composite heat insulating material in which fine particles are uniformly contained in the entire fiber structure.

FIG. 4 is a perspective view of a fiber / particle composite heat insulating material having a dense heat insulating material surface.

[Explanation of symbols]

 1 Fiber / fine particle composite insulation material (a) Fiber structure (b) Fine particle layer (c) Fine particles (d) Fiber (e) Waterproof sheet

Claims (3)

[Claims] 1. A fibrous structure 1 having a bulk density of 0.01 g / cm ³ or more formed by entanglement and / or adhesion of fibers.
A fiber / fine particle composite heat insulating material in which 1 to 250 parts by weight of fine particles having an average particle diameter of 1 μm or less are held by the fiber structure in a space of 00 parts by weight. 2. The nonwoven fabric according to claim 1, wherein the fibrous structure is a nonwoven fabric.
The fiber / particle composite heat insulating material described in the above. 3. The method according to claim 1, wherein the fine particles are silicon oxide, titanium oxide,
The fiber / particle composite heat insulating material according to claim 1 or 2, which is at least one fine particle selected from inorganic fine particles such as carbon black and / or polymer fine particles such as polyvinyl chloride resin fine particles and acrylic resin fine particles.