JPH0916180A - Ceramic sound absorbing material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an improved sound absorbing material which obviates the occurrence of degradation in strength and the dislodgment of ceramic particles in spite of exposure to a hightemp. atmosphere, such as fire, by adding a resin binder and an inorg. binder to an oxide ceramic grains and subjecting this mixture to pressurizing and integal molding. SOLUTION: The oxide ceramic grains are used as aggregate and the resin binder and the inorg. binder are added thereto. The resulted mixture is pressurized and integrally molded. The inorg. binder is adequately borosilicate lead glass and has a compsn. consisting, by weight, of 35 to 65% PbO, 20 to 35% SiO2 , 5 to 20% B2 O3 , and the balance ZnO, Al2 O3 , and others. The coefft. of volumetric expansion of the binder is <=300×l0<-7> . The oxide ceramic particles used as the aggregate include mullite, etc., and the resin binder is preferably thermosetting resins, such as epoxy resins. As a result, the inorg. binder is made into a pasty form and play the role of preventing the dislodgment of the ceramic particles.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sound absorbing material used for roads, houses, buildings, etc., and more particularly to a sound absorbing material which does not deteriorate in sound absorbing performance even when it is watered down by rapid heat or rapid cooling such as fire.

[0002]

2. Description of the Related Art In a conventional method for producing a ceramic sound absorbing material which does not go through a firing step, generally, a resin-based binder is added to ceramic particles and well mixed, and the mixture is filled in a press die and press-formed. Then, it is taken out and dried at room temperature for 1 day or more to exert its strength (FIG. 3).

[0003]

A ceramic sound absorbing material of a type which does not burn at a high temperature using a conventional resin binder is burned out in a high temperature atmosphere such as a fire. Only the ceramic particles adhere to each other only by the pressing force in the pressing step, which causes a significant decrease in the strength of the sound absorbing material. In addition, sometimes the ceramic particles on the surface of the sound absorbing material are partially dropped. (In Table 1,). SUMMARY OF THE INVENTION It is an object of the present invention to solve the above problems of the prior art and to provide an improved sound absorbing material that does not cause strength reduction or dropping of ceramic particles even when it is watered down in a high temperature atmosphere such as a fire. .

[0004]

As a result of various studies to overcome the above-mentioned drawbacks of the prior art, the present inventors have found that ceramic particles fall off from the surface of the sound absorbing material even when exposed to a sudden high temperature atmosphere such as a fire. In order to prevent this, it was found that it is effective to add an inorganic binder as a binder (FIG. 1) in addition to the conventional resin binder. Here, the inorganic binder used is
It is necessary to be in a molten or semi-molten state at a fire temperature of about 500 to 800 ° C., and to have a sticky paste-like state having a certain degree of viscosity (FIG. 2).

That is, the gist of the present invention is a ceramic sound absorbing material obtained by integrally molding an oxide ceramic granule as an aggregate by adding a resin binder and an inorganic binder thereto and pressurizing the mixture. It is a thing. The inorganic binder used here preferably satisfies the above-mentioned needs, and for example, lead borosilicate glass is suitable, and one having the following composition and characteristics is particularly preferable. PbO: 35 to 65% _{(wt%) SiO 2: 20~35% B} 2 O 3: 5~20% ZnO, Al 2 O 3, other: having the composition and the balance, and volume expansion coefficient of 300 × 10 ^-7
The following: The oxide ceramic particles used as the aggregate include, for example, mullite, and the resin binder is generally preferably a thermosetting resin such as an epoxy resin.

When a sound absorbing material to which both a resin binder and an inorganic binder are added encounters a fire, a rapid temperature rise occurs and the temperature is raised to 500 to 800 ° C. for a short time. Extinguished or extinguished within a short time. While the resin-based binder disappears during this short-time temperature rise, the inorganic-based binder becomes a molten or semi-molten state,
At this time, although the strength of itself is not high, it becomes so-called glue-like (or molten glass-like) and serves to prevent the ceramic particles from falling off from the surface of the sound absorbing material.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Therefore, as a low melting point inorganic binder, phosphoric acid (P ₂ O ₅ based) or boric acid (B ₂ O ₃ based) is used.
System), lead system (PbO system) and mixtures thereof. First, a phosphoric acid type, for example, SM-5 (trade name, manufactured by Nippon Frit Co., Ltd., containing 35% to 40% of P ₂ O ₅ as a main component) has a high body expansion coefficient (450 × 10 ⁻⁷ ), and therefore is particularly quenched In this case, cracking occurs in itself and the strength is remarkably reduced, which is not suitable as a binder.

Next, in a boric acid system, for example, PR520
3 (product name by Nippon Frit Co., Ltd., B ₂ as the main component)
O ₃ 35 to 40% content, and other Al ₂ O ₃ and SiO ₂ content) have a slightly higher body expansion coefficient (350 × 1).
0 ^-7 ), the melting temperature is as high as about 800 ° C, so it does not form a paste in the case of fire and does not serve as a binder, and even if it melts it is not suitable as a binder because cracks easily occur during quenching. .

In the lead system, for example, XM-735L
(Product name of Nippon Frit Co., Ltd., with PbO as the main component)
40 to 45%, and other materials including SiO ₂ and Al ₂ O ₃ have a low body expansion coefficient of 170 × 10 ^−7, and no cracks are observed during rapid cooling after melting. However, the melting temperature is 800-90
Since it is as high as 0 ℃, it does not serve its purpose in case of fire. Therefore, various tests were conducted on lead-based materials having a low body expansion coefficient and low melting temperatures. As a result, as a guide, the body expansion coefficient is 300 × 10 ⁻⁷ or less and the softening temperature is 350 ° C.,
It has been found that one having a melting temperature of 400 to 600 ° C. exerts an effect as a non-material binder in the case of rapid heat such as fire and rapid cooling.

To satisfy this condition, Pb
Lead borosilicate glass composed of O, B ₂ O ₃ , SiO _{2 and the} like is preferable. The P ₂ O ₅ system is not preferable because it has a high expansion coefficient. Lead borosilicate glass with a body expansion coefficient of 3
It is necessary to set B ₂ O _{3 to} 20% or less in order to set it to 00 × 10 ^-7 or less, and Pb to lower the melting temperature.
It is necessary that O is 35% or more, B ₂ O _{3 is} 5% or more, and further SiO ₂ and ZnO are appropriately blended therein.

The lead borosilicate glass content is preferably in the range of 100: 3 to 20: 2 to 10 by weight of ceramic particles: lead borosilicate glass: resin binder. If the content of lead borosilicate glass is 3% or less, the effect of increasing the strength after quenching cannot be expected, and the effect of the binder at high temperature is also low. Further, as the amount is increased, the strength can be expected to be increased, but the porosity is decreased, and the sound absorbing performance is greatly affected. The resin binder is
It is added in order to secure the strength at low temperature in an atmosphere which is always used as a sound absorbing material, but 2 to 10% is preferable, and strength is insufficient at 2% or less, and porosity decreases if it exceeds 10%. , It has been found to affect the sound absorption performance.

[0012]

The present invention will be described in more detail with reference to the following examples. (Example 1) Production of ceramics sound absorbing material (i) Ceramics particles (pulverized mullite particles having a diameter of about 0.5 to 1 mm) ... 5,000 g (ii) Epoxy resin adhesive ... 100 g (iii) Lead borosilicate glass (# 4370) ... 500 g (manufactured by Nippon Hollow Glaze Co., Ltd.) of the above raw materials were well mixed with a mixer for about 20 minutes. The obtained mixture was filled in a press die (450 mm × 900 mm) and press-molded at a pressure of about 200 tons to obtain a sample having a size of 450 × 900 × 9 mm.
This was taken out from the mold and dried at room temperature for 1 day or more to cure the adhesive, and a sound absorbing material having a considerable strength was obtained. The flexural strength (in Table 1) was 140 kg / cm ² . The sound absorption coefficient of this composition is shown in FIG. Next, 750 ℃
The sample was heated at room temperature for 30 minutes, then rapidly cooled and returned to room temperature, and the strength was measured and found to be 80 kg / cm ² (Table 1
of). In FIG. 4, the solid line shows the sound absorption coefficient of the sample before heating, and the dotted line shows the sound absorption coefficient of the sample cooled after the heat treatment at 750 ° C. for 30 minutes.

(Comparative Example 1) The bending strengths of the samples obtained by treating in the same manner as in Example 1 except that borosilicate glass was not blended are shown in and of Table 1.

[0014]

[Table 1]

[0015]

By using lead borosilicate glass as the inorganic binder, it is possible to prevent ceramic particles from falling off even in the case of a sound absorbing material that has not undergone a firing step even during a rapid heat such as a fire. In addition, even after cooling after extinguishing, it melted and solidified, and lead borosilicate glass served as a bonding agent for ceramic particles, had appropriate strength, and had the effect that it could be reused as a sound absorbing material. .

[Brief description of the drawings]

FIG. 1 is a schematic view showing an embodiment of a ceramics sound absorbing material of the present invention.

FIG. 2 is a schematic view showing a state in which an inorganic binder used in the ceramics sound absorbing material of the present invention is melted.

FIG. 3 is a schematic view showing an example of a conventional ceramic sound absorbing material using a resin binder.

FIG. 4 is a graph showing the reverberation chamber method sound absorption coefficient before and after heating the sound absorbing material of the present invention.

Claims (3)

[Claims] 1. A ceramic sound-absorbing material obtained by using oxide-based ceramic granules as an aggregate and adding a resin-based binder and an inorganic binder to the mixture to pressurize and integrally mold the mixture. 2. The ceramic sound absorbing material according to claim 1, wherein the inorganic binder is lead borosilicate glass. 3. A composition comprising lead borosilicate glass in a weight ratio of PbO: 35-65% SiO ₂ : 20-35% B ₂ O ₃ : 5-20% ZnO, Al ₂ O _3, and the balance. Has and has a body expansion coefficient of 300 × 10 ^-7
The ceramic sound absorbing material according to claim 2, which is as follows.