JPS6365616B2 - - Google Patents

Description

[Detailed Description of the Invention] (a) Object of the Invention (Field of Industrial Application) This invention relates to foamed glass beads and a method for producing the same. More specifically, it is lightweight and useful as heat insulating material, aggregate, sound insulation/magnetic material, radio wave absorbing material, etc.
This invention relates to a glass foam particle containing a metal layer and a method for producing the same.

(Prior Art) Conventionally, as a method for obtaining relatively lightweight granular molded bodies made of glass, glass powder and decomposable foaming agent powder are mixed, a binder is added to the mixture, and the mixture is granulated to an appropriate size. There is a known method in which the granules are then heated to melt and sinter the glass powder while foaming to obtain spherical foamed glass particles.

(Problems to be solved by the invention) However, the conventional method has the disadvantage that the granulation process requires a long time, and furthermore, it is difficult to grow the mixed powder and granulate it uniformly, resulting in a wide range of particle size distribution. It was difficult to obtain uniform glass foam particles because of the presence of wide base particles. When uniform glass foam granules are intended, it is necessary to carry out a sieving step for the granules before the sintering and foaming steps, which makes the manufacturing operation more complicated. Moreover, the glass foam particles obtained in this manner are relatively heavy because they do not have a hollow interior, which poses a problem in their use as practical materials for the purpose of weight reduction.

To solve this problem, the inventor first coated the core material with a mixture of glass powder and a decomposable blowing agent using a binder, and then the core material could burn and the glass powder could melt. By heating to a temperature of
Hollow glass foam particles have been obtained, and this invention is a development of such previous knowledge, and in addition to solving the above problems, it has sound insulation, magnetic properties, radio wave absorption properties, etc. The present invention aims to provide useful glass foam particles and a method for producing the same.

(b) Structure of the invention Thus, according to the invention, combustible particles are used as a core material, and a mixture of glass powder and a decomposable foaming agent and metal powder are alternately coated on this core material using a binder. By forming a glass powder layer with at least one metal powder layer interposed inside the glass powder layer, and then heating to a temperature at which the core material burns and the glass powder melts, the interior is hollow and at least one shell layer is formed. Provided is a method for producing foamed glass granules, which is characterized in that the foamed glass granules are composed of a foamed glass layer with two metal layers interposed therebetween and have a bulk density of 0.1 to 1.0 g/cc.

The combustible particles used as the core material in this invention include natural products, synthetic products, and any shape regardless of their shape, as long as they can be combusted at the melting temperature of glass, such as pieces of plastic, wood powder, paper powder, straw, etc.
Various materials can be used, such as short rushes, plant seeds, leaf pieces, rice husk, short pieces of oak, thread, cotton, etc., but it is usually preferable to use spherical plastic particles or plastic foam particles, especially plastic particles. Preference is given to using expanded particles. An example of such expanded plastic particles is expanded polystyrene particles, which have a diameter of 0.3 mm.
As mentioned above, it is usually preferable to set it to 1 mm to 10 mm.

In this invention, the decomposable foaming agent to be mixed with the glass powder includes various powdered compositions that can be thermally decomposed to generate gas during heat treatment, which will be described later. Foaming agents may be mentioned. Among these, it is preferable to use a carbonate such as calcium carbonate or a carbon dioxide gas generating agent such as carbon powder.

In the present invention, various metal powders can be used as the metal powder for forming the metal layer, but lead powder, iron powder, etc. are preferably used. Note that it is appropriate for the metal powder to be used to pass through 100 meshes.

The mixing ratio of the glass powder and the decomposable blowing agent is usually preferably adjusted so that the blowing agent is in an amount of 0.5 to 10 parts by weight per 100 parts by weight of the glass powder. If it is less than 0.5 part by weight, it becomes high density and
If the amount exceeds 10 parts by weight, the cell membrane of the foamed cells will be broken, forming open cells, resulting in water absorbency and deterioration in strength, which is not preferable. Note that the glass powder to be used is suitably one that passes through 100 meshes.

The above-mentioned mixture with the glass powder decomposition type blowing agent is first coated on the core material. The coating in this case is performed using a binder. As this binder, it is appropriate to use a solution of a substance having a so-called thickening effect, such as an aqueous solution of water-soluble polymers such as polyvinyl alcohol, carboxymethyl cellulose, and starch.

A specific coating method involves moistening the above-mentioned binder onto the core material by means such as spraying, and then rolling this core material over a mixture of glass powder and decomposable foaming agent to adhere this mixture to its outer periphery. Suitably, this is carried out by continuing rolling and growing an adhesion layer while spraying a binder as appropriate. However, in addition to this, it is also possible to contact and coat the core material with a mixture consisting of glass powder, a decomposable foaming agent, and a binder. That is, the granulation method can be a conventional method or a method similar thereto. In the case of the above-mentioned rolling method, for example, the core material moistened with a binder is placed on top of the glass powder and rolled there to adhere the glass powder, and then moved onto the decomposable blowing agent powder and rolled there. By moving the glass powder to deposit the foaming agent and repeating this operation alternately, it is also possible to form a mixed layer without mixing the glass powder and the foaming agent in advance. On the thus formed layer of the mixture of glass powder and decomposable blowing agent, metal powder is similarly coated using a binder.

The above two types of layer formation are repeated alternately in order to form a glass powder layer with at least one metal powder layer interposed therein. At this time, the number of metal powder layers interposed in the glass powder layer can be changed as appropriate depending on the objectives such as the crushing strength required for the sound insulating material, radio wave absorbing material, and aggregate.

The coated structure thus formed with a glass powder layer with at least one metal powder layer interposed therein is then subjected to a heat treatment. The heat treatment is usually carried out by holding the glass in a high-temperature heating furnace for a predetermined period of time at a temperature at which at least the core material burns and the glass particles fuse together. The temperature at this time depends especially on the melting point of the glass powder used, but is usually
700-900℃ is suitable. In addition, the heating time is 1~
10 minutes is enough.

Through such heat treatment, the core material burns, and the combustion gas passes between the coating particles, escaping and disappearing, but at the same time, the foaming agent in the coating layer decomposes and bubbles are created in the glass powder layer that is being fused. As a result, glass foam granules are obtained, which are granules having a hollow portion inside, and the shell layer of the granules is composed of a glass foam layer with at least one metal layer interposed therebetween.

In addition, the glass foam particles obtained in this way are
It usually has a bulk density of 0.1 to 1.0 g/cc, and is lighter than conventional glass foam particles.

According to the manufacturing method of the present invention, the size of the obtained foamed glass particles depends particularly on the size of the core material, but usually 1 to 25 mm can be efficiently obtained. In addition, the size of the hollow part can be controlled as appropriate, but in particular 20 to 90% of the outer diameter (for strength reasons)
It is possible to efficiently obtain foamed glass particles having a hollow portion with a diameter of 30 to 70% (preferably 30 to 70%).

Note that, as far as the present inventors know, the glass foam particles obtained in this manner are themselves novel molded bodies. Therefore, the present invention provides a granular body having a hollow portion inside, the shell layer of the granule being composed of a glass foam layer with at least one metal layer interposed therebetween, and having a bulk density of 0.1 to 1.0. The present invention also provides glass foam pellets characterized by a g/cc.

The number of metal layers in the shell layer of the foamed glass granules of the present invention can be varied depending on the desired properties and purpose of the foamed glass granules, but usually from the viewpoint of use as a lightweight aggregate and heat insulating material. , 1, preferably 1-3.

EXAMPLES The present invention will be described below with reference to Examples, but the present invention is not limited thereby.

Example 1 SiO ₂ (72.5wt%) and Na ₂ O as glass components
(14.4), CaO (10.), Al ₂ O ₃ (2.0), BaO (0.6),
A waste glass bottle having a composition of K ₂ O (0.2) and Fe ₂ O ₃ (0.1) was pulverized to less than 200 meshes, and 5 parts of CaCO ₃ powder (approximately 400 meshes) as a foaming agent was added and mixed therein. Next, the diameter 2m/m is placed in a pan-type granulator.
Granules made of foamed polystyrene particles (expanded approximately 50 times) as a core material and coated with a glass powder foaming agent mixture to a film thickness of approximately 0.5 m/m using polyvinyl alcohol (2%) aqueous solution as a binder. I got something. Next, as iron powder, 100 mesh
The same binder as above was used to coat the structure to a thickness of about 0.3 m/m, and the same glass powder blowing agent mixture as above was further coated to a thickness of about 0.5 m/m to obtain a coated structure. After drying this structure, it was heated for 5 minutes in an electric furnace set at 800°C.

The object obtained as described above has an outer diameter of 7.0 m/
m, inner diameter 4.0m/m, bulk density 0.3g/cc, water absorption rate 3.7
They were hollow glass foam particles with a weight percent and crushing strength of 2 kg.

Furthermore, the glass foam particles obtained as described above are shown in FIG. As shown in the figure, the obtained foamed glass granules 1 are granular bodies having a hollow portion inside, which is composed of a hollow portion 2, a glass foam layer 3, and a metal layer 4.

Example 2 Glass foam particles were obtained in the same manner as in Example 1 except that 100 meshes of lead powder was used instead of the iron powder.

The obtained product has an outer diameter of 7.0 m/m and an inner diameter of 4.0 m/m.
They were hollow glass foam particles with a bulk density of 0.38 g/cc, a water absorption rate of 12.3% by weight, and a crushing strength of 1.5 kg.

(c) Effects of the invention Compared to conventional methods, the method of this invention uses a core material during granulation, which can significantly shorten the time required for the granulation process, and furthermore, the core material can be made of a predetermined particle size in advance. By using this, granulation with a uniform particle size can be easily performed. Therefore, substantially uniform glass foam particles with a narrow particle size distribution can be obtained in a short time. Moreover, since combustible particles are used as the core material and are burned and removed during sintering, the interior of the obtained foamed glass grains becomes hollow, reducing the apparent specific gravity, resulting in lighter foamed glass grains. It will be. Therefore, this is an extremely excellent method for producing foamed glass beads.

In addition, since at least one metal layer is interposed in the shell layer, the foamed glass particles have the characteristics of the metal used (for example, lead powder has sound insulation properties, iron powder has magnetic properties, etc.). Therefore, it exhibits excellent effects especially when used in sound-insulating building materials, radio wave-absorbing materials, etc.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway perspective view showing an example of the foamed glass grain of the present invention. 1...Glass foam particles, 2...Hollow portion, 3...Glass foam layer, 4...Metal layer.

Claims (1)

[Scope of Claims] 1. A granular body having a hollow portion inside, the shell layer of the granule being composed of a glass foam layer with at least one metal layer interposed therebetween, and having a bulk density.
Glass foam particles characterized by having a content of 0.1 to 1.0 g/cc. 2. Claim 1 in which the foam particles are approximately spherical
Glass foam particles as described in section. 3. Flammable particles are used as a core material, and a mixture of glass powder and decomposable foaming agent and metal powder are added to this core material.
The interior is formed by alternately coating with a binder to form layers of glass powder with at least one intervening layer of metal powder, and then heating to a temperature at which the core burns and the glass powder melts. is hollow, the shell layer is composed of a glass foam layer with at least one metal layer interposed, and the bulk density is 0.1.
A method for producing foamed glass beads characterized by obtaining foamed glass beads of ~1.0 g/cc. 4 Claim 3 in which the foam particles are approximately spherical
Manufacturing method described in section.