JP2002068853A - Lightweight heat insulation and its production method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lightweight heat insulation and its producing method, which is lightweight and excellent in heat resistance, high strength, thermal insulation property and processability. SOLUTION: Plural particles of fine hollow spherical glass material, which contain 70-80% SiO2, 3-8% Na2O, 8-15% CaO and 2-9% B2O3, and Na2O/B2O3 is 0.3-3.0, are charged into molds, molten the surfaces of the hollow spherical material at above the melting point and joined to integrate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a light-weight, heat-resistant,
The present invention relates to a lightweight heat insulator excellent in high strength and heat insulation and also excellent in workability, and a method for producing the same.

[0002]

2. Description of the Related Art In living spaces such as houses and buildings, materials having various functions are used in order to improve comfort. In particular, thermal insulation and sound absorbing materials are familiar because factors such as heat and sound greatly affect our lives. In recent years, the fields of application range from building materials such as floors and walls for living use to production facilities such as factories, home appliances and leisure products.

[0003] Specifically, in the old days, starting from refractory insulating bricks, there are glass fiber, calcium silicate, ceramic fiber, alumina fiber, and resin-based heat insulating material such as urethane foam. A characteristic required of such a heat insulating material is that the thermal conductivity is low. In other words, as the porosity of the heat insulating material increases, the density of the material decreases, and the effect of the heat insulating property increases. Further, such functional materials are used in various environments, and for example, the temperature ranges from a low temperature to a considerably high temperature.

[0004] Analyzing the conduction of heat, there are four main types. (1) solid conduction; (2) convection of gas; (3) radiation by infrared radiation; and (4) molecular conduction of gas. If the specific gravity of the heat insulating material is small, the thermal conductivity decreases, and the heat insulating performance improves. This is because the solid portion of the heat is reduced because the solid portion is small.

[0005] In addition to glass and ceramic materials, resin-type heat insulating materials such as urethane foam are also widely used, particularly for architectural uses, and their good heat insulating properties are widely known. However, the resin type heat insulating material has a problem in heat resistance because it is a resin, and its heat resistance temperature is limited to 80 ° C.

As one kind of such heat insulating material, a hollow heat insulating material (balloon) is also known. JP-A-52-2
No. 5823 discloses pearlite, alumina balloon,
A heat insulating material composed of hollow particles such as a shirasu balloon is described. In this known example, the filling rate is increased in combination with coarse particles and fine particles of hollow body particles, and granulation is performed with a binder such as polyvinyl alcohol. However, the thermal conductivity of this heat insulating material is 0.04 Kcal / m · h · ° C. (50 ° C.), and it is hard to say that it is particularly excellent in heat insulating properties as compared with heat insulating materials such as fibers. It is considered that the reason is that the packing ratio of the hollow particles is still low due to granulation using a binder.

Japanese Patent Application Laid-Open No. Hei 8-241085 discloses that a hollow particle having a shell, such as a shirasu balloon, is similarly molded using a binder, packed in an outer wrapping material, and decompressed by vacuum. , A soundproofing material is disclosed. However, such a material has a high degree of heat insulation performance, but has problems in production efficiency and shape workability, and is difficult to use easily in practical use.

[0008]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the conventional heat insulator, and is lightweight, heat-resistant,
The present invention relates to a lightweight heat insulator excellent in high strength and heat insulation and also excellent in workability, and a method for producing the same.

[0009]

Means for Solving the Problems The present inventor has conducted researches to solve the above-mentioned problems. As a result, in any case, a conventional heat insulator made of a hollow body such as a shirasu balloon adheres hollow body particles. It has been found that the presence of the binder reduces the volume occupied by the hollow portion in the heat insulator and lowers the heat insulator performance. However, the use of the above binder is indispensable for shirasu balloons and the like because the softening point is extremely large on the material thereof.

In addition, the hollow body such as a shirasu balloon used for the conventional heat insulator has a non-uniform particle size at the same time, has a high particle density, and is not sufficiently depressurized inside. It has also been found that non-uniformity is also a cause of insufficient heat insulation performance.

Thus, the present invention has been achieved in view of the above-mentioned points, and it has been found that SiO ₂ : 70-80%, Na ₂ O:
3~8%, CaO: 8~15% and B ₂ O _3: 2~9%
And B ₂ O ₃ / Na ₂ O: 0.3 The present invention provides a lightweight heat insulator characterized in that the surfaces of a plurality of particles of a glass micro hollow sphere having a diameter of up to 3.0 are joined together and integrated.

Further, according to the present invention, SiO ₂ : 70-80
_{%, Na 2 O: 3~8%} , CaO: 8~15% and B ₂
O ₃ : 2 to 9%, and B ₂ O ₃ / Na ₂ O: 0.3
A plurality of fine hollow spheres of glass having a particle size of ~ 3.0 are filled in a mold, and the surfaces thereof are melted and joined at a temperature equal to or higher than the softening point of the fine hollow spheres to integrate them. The present invention also provides a method for manufacturing a lightweight heat insulator.

The heat insulator of the present invention is formed from fine hollow sphere particles of glass having a specific composition, and its softening temperature is not so high, so that it does not require the use of a binder as in a conventional heat insulator. Bonding can be performed by softening the mutual surfaces of the hollow particles by heating. Therefore, the filling rate of the hollow body in the heat insulator can be extremely increased, so that the heat insulation performance can be increased. Moreover, since the hollow body particles themselves have high strength and the bonding of the hollow body particles is strong, the formed lightweight heat insulator is excellent in handling and workability.

Thus, according to the present invention, it is possible to obtain a lightweight heat insulator which is lightweight, excellent in heat resistance, high strength and heat insulation, and also excellent in workability. Hereinafter, the present invention will be described in detail.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Forming a heat insulator in the present invention
Micro hollow spheres of glass are made of glass with a specific composition.
The particles have a small apparent density and are almost uniform.
It is preferable that the first and the degree of vacuum in the hollow portion be large. This
Here, the apparent density of a particle is calculated by dividing the mass of the particle by the apparent body of the particle.
It is the value obtained by dividing by the product. Vitreous is SiO_Two:
70-80%, Na_TwoO: 3 to 8%, CaO: 8 to 15
% And B_TwoO_Three: Containing 2 to 9%, and B_TwoO_Three/ Na_Two
O ratio is 0.3 ~ 3.0. In the present invention
Indicates the percentage and ratio of glass components,
Unless otherwise indicated, mass is based. B_TwoO_Three/ Na_TwoThe ratio of O is
It is important that if the ratio is small, the weather resistance is low.
Lower, and conversely, higher costs increase
Not preferred. B_TwoO _Three/ Na_TwoParticularly preferred ratio of O
Is 0.5 to 2.0.

The vitreous components are SiO ₂ , Na ₂
In addition to the four components of O, CaO and B ₂ O ₃ , other components can be contained, and the total of the above four components is 85% by mass.
It is preferable that the content be at least 90% by mass. Other components include MgO, LiO, P
₂ O ₅ , SO _{3 and the} like are contained as necessary, and SO ₃ is contained in an amount of 0.05 to 1.0% by mass when a sulfur-containing substance is used as a blowing agent for forming hollow particles.
Contained.

The micro hollow sphere of glass used in the present invention has a particle diameter of 90% or more of the entire glass having a particle size of 5 to 150%.
It is preferably μm. Hereinafter, when the particle size is shown in a range, it is shown that 90% or more of the whole particle is in the range. When the particle size is smaller than 5 μm, the packing ratio of the obtained heat insulator is reduced, and the heat insulating property is reduced.
If the particle size is larger than m, the space between the particles of the heat insulator becomes large, which is not preferable. Above all, the above particle size is 20 to 1
10 μm is appropriate. In addition, the hollow microsphere of glass has an apparent density of 0.5 g or more of 90% or more of the whole.
/ Cm ³ or less. If the apparent density is larger than the above range, the heat insulating performance of the obtained heat insulator is deteriorated, which is not preferable. Above all, apparent density is
Preferably, it is 0.1 to 0.35 g / cm ³ . Too small an apparent density is not preferred because the strength of the hollow particles decreases.

The glass hollow body having the above properties used in the present invention is disclosed in JP-A-63-176338,
It is manufactured by the method described in JP-A-3-265542 and the like, and a commercially available product can also be used.

The heat insulator of the present invention is formed by joining the surfaces of the above-mentioned plurality of hollow glass micro-objects together and integrating them. Preferably, a plurality of glass micro hollow bodies are filled in a mold and heated to a temperature equal to or higher than the softening point of the glass micro hollow bodies, whereby the surfaces of the glass micro hollow bodies are melted and joined. A desired shape is selected for the shape of the mold according to the use form of the heat insulator, but a plate-like body is usually used.

The heating temperature in the above is higher than its softening point as described above, but if the temperature is excessively high, the shape of the hollow body is lost. According to the study by the present inventors, it has been found that a temperature that is higher than the softening point and within 50 ° C. from the softening point is preferable, and a temperature within 30 ° C. from the softening point is particularly suitable. In the present invention, for example, 700 to
Performed at 730 ° C.

When the heat insulator of the present invention is formed, it is not necessary to use a binder as described above, but a binder can be used if necessary. As such a binder, for example, a ceramic binder is preferable, and a binder having a melting point equal to or lower than that of the glass hollow body is preferable. The binder is preferably blended in an amount of 2 to 10% by mass with respect to the glass hollow body, and is preferably preliminarily mixed with the glass micro hollow spherical body and filled in the above mold.

The heat insulator obtained by the present invention has a high filling ratio of the glass spheres and exhibits excellent performance as a heat insulator. As an index indicating the heat insulating property, for example, there is a thermal conductivity. The thermal conductivity generally increases as the ambient temperature increases, and the heat insulating effect decreases. For example, with a conventional heat insulating material such as a shirasu balloon or a fly ash balloon, the thermal conductivity at 25 ° C. is 0.03.
Kcal / m · h · ° C., but 0.07 at 250 ° C.
Kcal / m · h · ° C., and cannot exhibit an excellent heat insulating effect. However, the heat insulating material of the present invention has a thermal conductivity at 25 ° C. of not more than 0.025 Kcal / m · h · ° C., and a thermal conductivity at 250 ° C. of 0.03 Kcal.
/ M · h · ° C or less, and is extremely excellent in heat insulation.

The heat insulator of the present invention has a high heat resistance because it is made of glass, and exhibits a heat resistance of at least 300 ° C. or more, and sometimes 700 ° C. or more. Here, the heat-resistant temperature indicating the heat resistance refers to the maximum temperature at which the bulk density of the heat insulator changes by 5% or less even when the temperature is maintained for 2 hours. In addition, the bulk density of the heat insulator of the present invention is 0.5 g / cm ³ or less, particularly 0.3 g / cm ³ , since its constituent is a glass micro hollow sphere having a small apparent density. It is.

Further, in the heat insulating body of the present invention, as described above, the glass hollow body particles are integrally and firmly fused to each other, and the glass hollow body itself has high strength.
Also excellent in strength. In addition, the heat insulator of the present invention can easily obtain a high-strength heat insulator molded in accordance with the mold by filling the hollow glass body into an appropriate mold and heating and melting as described above.

The heat-insulated molded body obtained in this way is an integral body having a sufficient fusion force and good workability. For example, a plate-shaped heat insulator can be easily cut by a saw or the like. A heat insulator having the following shape can be obtained.

The heat insulator obtained according to the present invention can be used for living floors,
It can be used as a heat insulating material in many fields such as building materials such as wall materials, equipment such as factories, parts of home electric appliances such as refrigerators, leisure products and the like.

[0027]

EXAMPLES Examples and comparative examples of the present invention are shown below. Example 1 SiO ₂ : 70.5%, Na ₂ O: 4.9%, CaO: 1
1.1% and B ₂ O _3: 7.8%, further, K ₂ O:
0.8%, ZnO: 1.0%, P 2 O 5: 1.8%, Al
₂ O ₃ : 0.9%, Li ₂ O: 0.9%, SO ₃ : 0.3%
And fine hollow spherical particles of glass having a B ₂ O ₃ / Na ₂ O ratio of 1.6 (softening point: 700 ° C., particle size: 23)
１０５105 μm, apparent density: 0.2 g / cm ³ ) 12 g
Was filled in a box-shaped alumina container 10 cm in length and width and 1 cm in depth.

This was placed in an electric furnace, kept at 700 ° C. and allowed to stand for 1 hour, and then a molded product was taken out of the alumina container. It was observed that the surface of each of the glass hollow bodies constituting the molded body was softened and mutually fused and integrated. Evaluate the performance of such a molded body as a heat insulator,
The results are shown in Table 1.

Example 2 The same glass material as in Example 1 was used, and the apparent density was 0.4 g.
A molded article was produced in the same manner as in Example 1 except that a hollow glass sphere having a diameter of / cm ³ was used.
The performance of this molded body as a heat insulating material was evaluated, and the results are shown in Table 1.

Example 3 SiO ₂ : 73.6%, Na ₂ O: 7.7%, CaO:
7.9% and B ₂ O _3: 5.5%, further, K ₂ O:
0.4%, ZnO: 1.1%, P 2 O 5: 1.8%, Al
₂ O ₃ : 0.8%, Li ₂ O: 0.8%, Fe ₂ O ₃ : 0.
2%, SO ₃ : 0.3%, and B ₂ O ₃ / Na ₂ O:
0.7 hollow glass particles (softening point: 700)
° C, particle size: 21-107 µm, apparent density: 0.3 / cm
^A molded article was produced in the same manner as in Example 1 except that ³ ) was used. The performance of this molded body as a heat insulating material was evaluated, and the results are shown in Table 1.

Example 4 The same glassy material as in Example 1 was used, and the apparent density was 0.7 g.
A molded article was produced in the same manner as in Example 1 except that a hollow glass sphere having a diameter of / cm ³ was used.
The performance of this molded body as a heat insulating material was evaluated, and the results are shown in Table 1.

Comparative Example 1 In Example 1, instead of the glass micro hollow body, an apparent
0.7g / cm density ^Three, Particle size is 2-30 μm, softening point
Is a 1050 ° C. shirasu balloon (component, SiO_Two: 7
0.0%, Na_TwoO: 2.3%, CaO: 1.9%, K_Two
O: 3.3%, MgO: 0.3%, Al_TwoO_Three: 15.5
%, Fe_TwoO_Three: 0.2%, LoI: 5.0%, and L
oI: 1000 ° C weight loss%), using an alumina container
Performed except that the holding temperature at
By carrying out in the same manner as in Example 1, a molded article was produced.
The performance of this molded body as a heat insulating material was evaluated, and the results
It is shown in Table 2.

Comparative Example 2 In Example 1, instead of the glass micro hollow body, an apparent
0.6g / cm density ^Three, Particle size 40 ~ 200μm, soft
Fly ash balloon having a crystallization point of 1020 ° C (component, S
iO_Two: 60.8%, Na_TwoO: 1.8%, CaO: 0.
8%, K_TwoO: 2.2%, Al_TwoO_Three: 28.3%, Fe_Two
O_Three: 2.4%, MgO: 1.7, LoI: 2%,
In addition, LoI uses 1000 ° C weight loss%) and uses aluminum
Example except that the holding temperature in the container was set to 1050 ° C.
By performing in the same manner as in Example 1, a molded body was produced. This
The performance of the molded body as a heat insulating material was evaluated, and the results were displayed.
It is shown in FIG.

Comparative Example 3 A molded article was produced in the same manner as in Comparative Example 2, except that water glass was used as a binder in an amount of 6% by mass based on the glass hollow body. The performance of this molded article as a heat insulating material was evaluated, and the results are shown in Table 2.

[0035]

[Table 1]

[0036]

[Table 2]

[0037]

Since the heat insulator of the present invention is made of a fine hollow sphere of glass having a specific composition, the particles have a small apparent density, are uniform, and have a large vacuum degree in the hollow portion.
The size is also uniform. Furthermore, since the softening temperature of the hollow body is not high, the mutual surfaces of the hollow body particles are joined by fusion by heating without using a binder unlike the conventional hollow body heat insulator, so the hollow body in the heat insulator Can be extremely increased, and thus the heat insulation performance can be extremely increased. Moreover, the strength of the hollow particles themselves is high and the bonding of the hollow particles is strong, so that the formed heat insulator is excellent in handling and workability.

Thus, according to the present invention, there is provided a lightweight heat insulator which is lightweight, excellent in heat resistance, high strength and heat insulation, and also excellent in workability, and a method for producing the same.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2E001 DD01 DD05 DH39 FA03 FA11 FA26 GA09 GA12 GA81 GA86 HA11 JA14 4G019 GA01 GA02 LA03 LB02

Claims (5)

[Claims] 1. A _{SiO 2: 70~80%, Na 2} O: 3~8
% CaO: 8 to 15% and B ₂ O _3: comprises 2-9% and B ₂ O ₃ / Na ₂ O ratio of 0.3 A lightweight heat insulator characterized in that the surfaces of a plurality of particles of a hollow glass microsphere having a particle size of up to 3.0 are joined to each other to form a body. 2. 90% or more of the hollow glass microspheres have a particle size of 5 to 150 μm and an apparent density of 0.5 g.
2 / cm ³ or less. 3. The lightweight heat insulator according to claim 1, which has a heat resistant temperature of 300 ° C. or higher. 4. SiO ₂ : 70-80%, Na ₂ O: 3-8
% CaO: 8 to 15% and B ₂ O _3: comprises 2-9% and B ₂ O ₃ / Na ₂ O ratio of 0.3 A plurality of particles of a glass micro hollow sphere having a size of ~ 3.0 are filled in a mold, and the surface is melted and joined at a temperature equal to or higher than the softening point of the micro hollow sphere to be integrated. Manufacturing method of lightweight insulation. 5. The method for manufacturing a lightweight heat insulator according to claim 4, wherein the difference between the temperature above the softening point and the softening point is 50 ° C. or less.