JPS58129489A - sound absorbing material - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sound absorbing material used in an exhaust silencer t for an internal combustion engine.

Traditionally, glass wool and porous ceramic materials have been used as sound absorbing materials for exhaust silencers for internal combustion engines.

There were gold-porous materials. However, when these materials are used as sound absorbing materials, when an internal combustion engine is operated, tar and soot, which are the combustion residues of fuel such as carbon, adhere to the surface and cause clogging in a relatively short period of time, reducing the sound absorbing performance. This often leads to intensified noise and adversely affects the fuel efficiency of internal combustion engines. Furthermore, when glass wool or porous ceramic material is used as a sound absorbing material in an exhaust silencer for an internal combustion engine, the pressure of exhaust gas is low, and
Because MljjJ is large, these sound absorbing materials sometimes become rusty or damaged, rendering them completely useless. When a porous metal body is used, the temperature of the exhaust gas inside the silencer is as high as 4°O to 800''O, and the exhaust gas contains corrosive sulfur oxides and nitrogen oxides, so a special heat-resistant alloy is used. If not used, corrosion deterioration due to high-temperature oxidation will occur, resulting in clogging due to corrosion products, and the i# rating of the porous material will corrode and disappear, making it useless as a sound absorbing material. Moreover, since the pore diameter is relatively large as a basic characteristic of metal porous materials, there are disadvantages such as the absence of materials with good sound absorption performance.Conventional sound absorption materials have major drawbacks as described above. However, none of them could be put to practical use as an exhaust silencer for internal combustion engines.

This invention eliminates all the drawbacks of the conventional ones, has good sound absorption performance, and prevents the deterioration of the v & soot rudder caused by the accumulation of tar and soot and clogging caused by these. The purpose of the present invention is to provide a sound absorbing material for a 1F device that can withstand simultaneous noise cancellation.

That is, the IIkft material of the present invention uses a gold porous material as a sound-absorbing base material, which is free from powdering or breakage, and has its sound-absorbing properties r to suppress clogging caused by tar and soot.
A solid acid catalyst is used mainly for three purposes: to improve the quality of the sound absorbing material, and to prevent corrosion deterioration due to high-temperature oxidation. A heat-resistant binder containing Kakokufune is coated and cured on a porous metal sound-absorbing base material.

The details of this invention will now be described with reference to Examples.

[Example 1] Powdered sintered metal IIj4 (f1ii product name Calum) manufactured by Nippon Diacrevite was used as a metal porous sound-absorbing base material, and the composition of Composition Example 1 below was applied to the surface (one side) of the powdered sintered metal IIj4 (F1II product name Calum).
The mixture mixed with r6 for 30 minutes was uniformly applied to the glass by spraying. Furthermore, this material was dried at 80'"C for 60 minutes and baked at dk 550°0 for 60 minutes to harden it. When applying the kneaded material, if too much coating material is applied, the sound absorption properties will deteriorate on the contrary. Therefore, caution is required.

(Composition Example 1) Solid acid catalyst: Natural zeolite 52% by weight Binder Nialuminum phosphate 20191% Additive: Silica stone, bentonite, water 23% by weight Low surface energy Anatomy: Graphite fluoride 5% by weight The IJQ agent has the effect of improving the coating properties and film performance as a coating material, and increases the strength and adhesion performance to the underlying porous material after the coating film is formed, and has the property of making the skin 111' porous. It has the following.

The sound absorbing material of the present invention produced in this manner has a structure as shown in an enlarged cross section in FIG. That is, (1)
are gold-porous particles, (2) are solid acid catalyst particles, (3)
(4) is a binder containing solid acid catalyst particles (2) and fluorinated graphite (5) and penetrating into the voids between the particles (1) of the gold J1g porous body; 2) and Bukka Kurofune (5)? This is a porous cage formed on the surface by applying a bonding agent (3) of 1f4i. Using the sound absorbing material of this invention, the composition of Composition Example 1 is not waxed at all! The performance τ was investigated by comparing it with that of only 4-porous material.

Figure 2 shows the effects of corrosion when left in air containing 5 ppm of sulfur dioxide (sulfur dioxide gas) for 72 hours at a temperature of 400 to 800"O using a Section 1 furnace.
0 curve 1, which shows L and a half, is the sound absorbing material of the present invention partially made as described above, and the curve is the same material**. show,
As is clear from FIG. 2, the sound absorbing material of the present invention has an exhaust gas temperature of 40
0 to 8 oo'a, and even in air containing nicked sulfur, corrosion hardly progresses and it has good resistance. Compared to this, conventional metal porous materials are especially difficult to use! A very drastic weight change (reduction) occurs from 600aO, which is close to the melting point of .

This depends on the high-temperature oxidation, but most of the time it's MU! This is due to the melting-vaporization of -White high-temperature oxidation products (scale) were observed on the surface.

Figure 6 shows normal incidence sound absorption x! measured under the same conditions using the in-pipe method (JIS A 1405). This is what the IA has shown. Curve 0 is the characteristic of the sound absorbing material of the present invention, and curve d is the characteristic of the sound absorbing material consisting only of affiliated porous bodies. It can be seen from FIG. 6 that the sound absorbing material of the present invention has a higher mi ratio than that of a sound absorbing material made of only a metal porous body. This is because the structure shown in Figure 1, which is obtained by curing the composition of Composition Example 1 with a magnetic cloth from the surface of the metal porous body, is also porous in nature, so air can circulate inside it. Depends on what you can do. That is, the coated cured product of the composition example itself forms a part of the sound absorber, and the sound absorption coefficient can be adjusted depending on the method of coating.

Next, the two types of sound absorbing materials mentioned above were molded into a cylindrical shape and incorporated into the exhaust silencer of a commercially available domestically produced passenger car (exhaust 11.800Qo), which was driven around 10,000 times.
Figure 4 shows a characteristic diagram of the noise reduction performance measured using the 1616 and compared with the initial value before the traverse.

Curves 1 and 2 are the initial and actual running strength characteristics, respectively, when using the J-absorbing material of this invention, and the curve ft
'j5 and f! are the initial characteristics (I) and the characteristics after actual running when using the conventional sound absorbing material made of only 111 pieces of metal. It goes without saying that the initial performance is good, but even after 1 in 10,000 actual runs, the initial performance is almost unchanged, whereas the material using 1ift material made of porous gold only has good performance after 1 in 10,000 actual runs. After 10,000 Kll, the silencing performance decreased significantly in all measured frequency bands.
! After the measurement, we took out the sound absorbing materials of both materials and visually observed them, and found that the sound absorbing material of this invention was almost clean compared to the initial and co-worker, but the material with only the metal porous material had black color on the entire surface. Combustion residue in the form of tar and soot, as well as colored charcoal products, adhered to many sources, causing a stale clogging. In other words - as can be seen from this result,
In the sound-absorbing material of this invention, the solid acid catalyst particles fractionally attached to the sound-absorbing base material are activated by the temperature of the exhaust gas, and are oxidized (polymerized) on the surface of the sound-absorbing material in the exhaust gas. In addition, because the components were made to have lower molecular weight to make them easier to differentiate, they were purposefully vaporized (purified) at the temperature of the exhaust gas without forming a layer as tar. In addition, since the upper aa base material is broken with the atomized graphite fine particles, the soot adhesion prevention effect and soot adhesion dispersion effect of the aaa base material are fully exerted, and as a result, the initial noise reduction performance is almost the same. It is considered that it has been maintained. A solid catalyst is a substance that has the function of releasing protons (ti) or accepting pairs of electrons.In the petrochemical industry, the above-mentioned catalytic function is used to treat high boiling point (4 &! vaporized substances) oils. This is well known as so-called cranking, in which oil is catalytically cracked and converted into light oil with a low boiling point (low lA vaporized substance).

The above-mentioned agglomerated graphite and pond components are capable of effectively exhibiting their respective four functions at 5 to 95 weight %, but at best, both are 50 Jim %.

[Example 2] As a porous sound-absorbing base material, powdered sintered metal (gunmetal, 255 m thick) manufactured by Sintered Metal Industry Co., Ltd. was used, and lower period composition example 2 was used.
The mixtures of and 6 were kneaded in the same manner as in Example 1, and then sprayed onto the sintered metal and baked to harden to obtain the sound absorbing material of the present invention.

(Composition Example 2) Solid acid catalyst: activated clay 48% by weight
Mixture: Silicone resin 17% by weight Additives: Magnesium mothride, 23% by weight thinner, surface energy 1 Material: Graphite fluoride 12% by weight (Composition Example 6) Solid acid catalyst: Silica silcony 12% by weight Silica mag book shear 29% by weight Binder: Sodium silicate 22% by weight Additives: Alumina, calcium carbonate, water 50% by weight
Typical surface energy substance: graphite fluoride 7% by weight This sound absorbing material and the same porous metal body as above, without any coating of the compositions of Composition Examples 2 and 6, were completely different from those of Example 1. I checked the performance. As a result, the sound-absorbing materials of the present invention in which the compositions of Composition Examples 2B and 5 were coated and cured exhibited both corrosion resistance, l&sound modulus, and temporal changes in sound-dampening performance due to soot adhesion prevention and clogging prevention. In this case, Figs. 2 to 4 of Example 1 also apply.
It was found that the characteristics were almost as good as those shown in the figure.

By the way, the solid acid catalyst used in this invention is as follows:
In addition to composition examples 1 to 6, activated alumina, silica alumina, and vanadium pentoxide are used.

There are alumina boria, rubite 1 synthetic biolite, +12 white clay 1, etc.

Furthermore, as the gold porous body used as the base material in this invention, in addition to foamed metals and sintered metals as in the examples, commercially available general-purpose materials such as metal fibers and inorganic fiber-reinforced gold bridges can be used. . As for the materials, in addition to Mu1 and bronze, there are also Ml, 1・-Or, 1m-M
Alloy materials such as i-Or and 11 m-Or-Mul can also be used.

The heat-resistant binders used in this invention include - fluorescein (vitreous frits), alkali metal silicates, colloidal silica, colloidal alumina, phosphoric acid salts,
Examples include cements, silicone resins (faces), and mixtures thereof.

The graphite used in this invention has one fluorine atom attached to each vertical cable atom through a covalent bond! It is a chemically very stable white to gray fine powder that is tightly bound to 1lII, and is manufactured by directly reacting fluorine generated by an anhydrous IT solution with the longitudinal cables. .

Its properties include low surface energy and a small coefficient of friction, so it has been put into practical use as a solid detergent. In this invention, the most suitable method for dispersing and adhering the 4-lead oxide onto the surface of a porous material is to apply and bake it dispersed in a resin binder or m*-free binder, as in the case of Sou. However, when gold is used as a porous material as in the present invention, a method of eutectoid plating the surface of the porous material with heat-resistant materials such as Ml or Or is also effective.

It was also effective to use a commercially available spray set and face-shaped fluorinated graphite dispersed in a resin binder.

The d-absorbing material of this invention is intended to be used in an exhaust extinguishing device for an internal combustion engine, but depending on how it is used, it may
It may also be used as a sound absorbing material in other equipment such as.

As explained above, the sound absorbing material of the present invention uses a porous metal body as a base material and contains a solid acid catalyst and abutted graphite in a heat-resistant binder coated and cured on the porous metal body. If there is, it has good sound absorption performance, excellent high temperature oxidation resistance and corrosion resistance, and when used as a sound absorption material for an exhaust silencer for an internal combustion engine, it can prevent the build-up of tar and soot and prevent clogging at once. It is possible to prevent the deterioration of the silencing performance that occurs and maintain the initial good silencing performance. Therefore, due to its high performance and long life, it can be widely used in exhaust quenching devices for internal combustion, including motor vehicles.

[Brief explanation of the drawing]

FIG. 1 is an enlarged view showing an example of the sound absorbing material of the present invention.
FIGS. 2 to 4 are characteristic diagrams showing the performance of the sound absorbing material of the present invention. In the figures, the same reference numerals indicate the same or corresponding parts, (1) gold porous particles, (2) solid acid catalyst particles, (3) binder, (4) porous coating, ( 5) is fused graphite. Substitute Shin Kuzuno - (1 other person) -63ε

Claims (1)

[Claims] A sound absorbing material having a porous metal body as a base material and containing a solid catalyst and graphite fluoride in a heat-resistant binder that is applied and hardened to the porous metal body.