JPH01182516A - Muffler using heat resistant resin - Google Patents

Abstract

PURPOSE:To reduce noise in a muffler by forming a muffler body of at least one kind of inorganic matter and heat resistant resin, and setting a concentration gradient so that the concentration of the inorganic matter may have the highest value near an inner wall face of the muffler body, and decrease in order with approach toward its outer wall face. CONSTITUTION:A muffler has a cylindrical or an elliptical cylinder-shaped muffler body 1, whose both ends are connected with end plates 4, 5 having an input and an output pipe 2, 3 for exhaust gas respectively, and these parts are mainly formed of heat resistant resin. The insides of the muffler body 1 and the end plates 4, 5 are covered with inorganic matter, whose concentration is set to have a concentration gradient which is highest near the inner wall faces of the muffler body 1 and of the end plates 4, 5, and lowers in order from their inner wall faces toward their outer wall faces. Noise caused by an engine can therefore be effectively eliminated to improve the muffling performance of the muffler.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is installed in internal combustion engines including gas turbines and jet engines of automobiles, agricultural machinery, ships, and other industrial engines. This invention relates to an exhaust muffler that attenuates exhaust sound while allowing generated exhaust gas to pass through.

Conventional Technology Generally speaking, when the high-temperature, high-pressure gas discharged from an internal combustion engine is released into the atmosphere as it is, the exhaust gas expands rapidly and makes a lot of noise, so a muffler, usually called a muffler, is installed in the exhaust gas passage. is inserted to average pressure changes in the exhaust gas and release it into the atmosphere as a smooth airflow.

The above muffler has a muffler body (body part) in the shape of a substantially cylindrical, elliptical, or rectangular tube, with a head plate connected to an exhaust gas input pipe and a head plate connected to an output pipe at both ends. Furthermore, the inside of the muffler body is divided into small chambers,
By sequentially passing the exhaust gas through these small chambers, the gas pressure is lowered and the gas is dissipated to the outside as a substantially equal pressure gas flow, thereby suppressing the explosion noise of an internal combustion engine or the like. Additionally, a method of increasing the soundproofing effect by attaching a sound absorbing material to the inside of the muffler body is also used.

In addition, automobile exhaust systems contain N08 and HC as pollutants.
(hydrocarbons) and CO, the maximum levels of these pollutants are regulated based on law. Therefore, in some cases, internal combustion engines have a built-in three-way catalyst in order to reduce the pollutants below the regulatory value, but since the above-mentioned three-way catalyst is an exothermic reaction, Exhaust gas released at 500 to 700°C is heated to 800 to 850°C and passes through the muffler body, so the ionic gas generated by the reaction between the three-way catalyst and the exhaust gas is heated to 800 to 850°C. Therefore, it is important to improve the heat resistance and corrosion resistance of the muffler body. Generally, a metal material such as carbon steel or stainless steel is used as the material for the muffler body.

Problems to be Solved by the Invention However, in such conventional silencers, the muffler body is constructed using metal materials such as carbon steel or stainless steel, and these metal materials themselves have Since the sound absorption effect is very low, there is a problem in that the sound absorption characteristics of the muffler itself are limited within a predetermined area. In other words, the airflow noise of exhaust gas includes noise inside the muffler caused by high-speed exhaust flow colliding with the wall of the muffler body, and jet noise caused by the expansion of exhaust gas when it is released into the atmosphere from the muffler body. However, the above-mentioned noise inside the muffler is amplified by the collision of the exhaust flow with the metal and the resonance phenomenon at a specific frequency. However, metals such as carbon steel or stainless steel have very little sound absorption effect and do not have the effect of reducing resonance sound, so it is not possible to reduce the noise inside the muffler. Furthermore, the carbon steel muffler has the disadvantage that it is easily corroded by various impurities or salts contained in exhaust gas and the atmosphere.

On the other hand, if glass wool or asbestos is attached as a sound absorbing material to the inside of the Afflour body, the resonance sound can be absorbed by the action of the sound absorbing material, but these glass wool, asbestos, etc. are emitted into the air and pollute the atmosphere. There are problems in its use as it may become a source of pollution that may harm the health of workers. Incidentally, since the metals such as carbon steel and stainless steel all have a high specific gravity, they also have the disadvantage that the weight of the muffler body is also large.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a muffler that further improves the muffling effect by solving the problems that conventional mufflers have and particularly by reducing the noise inside the muffler. It is something to do.

Means for Solving the Problems In order to achieve the above-mentioned object, the present invention sequentially passes exhaust gas generated from an internal combustion engine from an input pipe attached to a muffler body to an output pipe, thereby preventing the explosion of the internal combustion engine. In the muffler for muffling exhaust noise, the muffler main body is made of at least one inorganic material and a heat-resistant resin, and the concentration of the inorganic material is highest near the inner wall surface of the muffler main body, and the muffler main body is made of at least one kind of inorganic material and a heat-resistant resin, and the concentration of the inorganic material is highest near the inner wall surface of the muffler main body, and the muffler main body is made of at least one kind of inorganic material and a heat-resistant resin. The structure has a concentration gradient that gradually decreases as the concentration increases.

Function When the heat-resistant resin that makes up the muffler body is heated to around the glass transition temperature (Tg) of the resin, it changes from a glass region to a viscoelastic region, and at that time, the elastic modulus changes significantly and This results in the effect of absorbing frequency noise.

The point of displacement to the viscoelastic region can be freely changed by changing the type of heat-resistant resin used and, if the heat-resistant resin is a thermosetting resin, the curing conditions of the resin. As a result, a silencer using heat-resistant resin can reduce exhaust energy in any frequency band and absorb noise.

Furthermore, since the concentration of inorganic substances in the heat-resistant resin constituting the muffler body is highest near the inner wall surface of the muffler body and gradually decreases from the inner wall surface toward the outer wall surface, Even when the exhaust gas temperature becomes extremely high, the muffler body is protected from high temperatures, allowing it to maintain its original function for a long time.

EXAMPLES Below, various examples of a silencer using a heat-resistant resin according to the present invention will be described with reference to the drawings.

FIG. 1 is a cross-sectional view of a main part of a muffler showing a first embodiment of the present invention. In the figure, 1 is a cylindrical, elliptical or prismatic muffler main body (body part); A mirror plate 4.5 to which an exhaust gas input pipe 2 and an exhaust gas output pipe 3 are connected is connected to both ends of the main body 1. The muffler main body 1 and end plate 4.5 are made of conventional carbon steel or stainless steel.
The muffler body 1 is mainly made of heat-resistant resin, and is processed and molded by adding a reinforcing material 6 to the inner center of the muffler body 1 and end plate 4.5. In FIG. 1, the reinforcing material 6 is located approximately at the center, but the reinforcing material 6 is not necessarily limited to this position. 7 is an inorganic substance distributed inside the muffler body 1 and the mirror plate 4.5, and the concentration of the inorganic substance 7 is highest near the inner wall surface 1a of the muffler body 1;
A concentration gradient is provided such that the concentration gradually decreases toward the outer wall surface 1b. Further, the concentration distribution of the inorganic substance 7 within the mirror plate 4.5 is also similar to the concentration distribution of the muffler body l.

When the head plate 4.5 is made of the same type of heat-resistant resin as the muffler body 1, the head plate 4.5 may be integrally molded at the same time as the muffler body 1, or the head plate 4.5 and the muffler body 1 may be separately molded. You can create them and concatenate them later. When the end plates 4 and 5 are made of a heat-resistant resin different from the muffler body 1, the end plate 4
, 5 and the muffler main body 1 may be created separately and then connected together. Further, it is preferable to use a heat-resistant material such as ceramic paper 9 on the surfaces of the input tube 2 and the output tube 3 in contact with the mirror plate 4.5.

FIG. 2 shows a second embodiment of the present invention, in which the tip of the output tube 3 connected to the end plate 5 is extended to the inside of the muffler body 1, and is made of the same heat-resistant resin as the muffler body 1. , and fixes the collision plate 8 containing the inorganic substance 7, and the concentration of the inorganic substance 7 is at the surface portion 8a with which the exhaust gas directly contacts.
It is the highest at the surface portion 8a, and gradually decreases from the surface portion 8a toward the output tube 3 side. Therefore, after the exhaust gas collides with the collision plate 8 as shown by the arrow, it detours and escapes into the atmosphere through the hole 3a of the output pipe 3.

The heat-resistant resin employed in the present invention can be appropriately selected depending on the temperature of exhaust gas discharged from the internal combustion engine. For example, epoxy resin, unsaturated polyester resin,
Diaryl phthalate resin.

Thermosetting resins such as phenolic resins, silicone resins, melamine resins, and thermosetting polycarbodiimide resins can be used. It is also possible to use not only one type of these thermosetting resins, but also a combination of two or more types of thermosetting resins. For example, at least one thermoplastic resin selected from polyamide resin, polyester resin, polyphenylene sulfide resin, thermoplastic fluororesin, polysulfone resin, and polyphenylene ether resin can be used.

When the heat-resistant resin used is an epoxy resin, at least one of acid anhydride, aromatic amine, dicyandiamide, etc. is added as a curing agent to the bisphenol-based jepoxy compound, and imidazole or tertiary as a curing accelerator. It is preferable to use amines or the like. In order to further improve the heat resistance of the above-mentioned epoxy resin, - an epoxy compound having three or more epoxy groups in the molecule, such as a phenol epoxy resin (Epicote-154, manufactured by Shell Kagaku KK), , N, N, N″-tetraglycidylamine resin etc. may be used in combination or alone.
It is also effective to use phenol novolak as a hardening agent. The heat resistance of epoxy resin varies depending on the type of epoxy resin used, curing agent, curing accelerator, and their blending amount, but the heat resistance of the epoxy resin depends on the load temperature due to exhaust gas in the muffler body l and the glass transition point (Tg point) of the epoxy resin. Preferably, the epoxy resin is selected to match.

When the heat-resistant resin used in the present invention is a diallyl phthalate resin that is solid at room temperature, an inorganic substance is mixed into a solution in which the monomer or oligomer and the peroxide used as a catalyst are dissolved in an organic solvent. It can be used by impregnating glass cloth with the prepared material and then evaporating the organic solvent to create a prepreg. There are three types of diallyl phthalate resins used in the present invention: diallyl orthophthalate resin, diallyl isophthalate resin, and diallyl terephthalate resin, and these resins can be used alone or in combination. It is also possible to use a mixture of diallyl phthalate resin and other resins such as unsaturated polyester resin.

If the temperature near the outlet in the input pipe 2 of the muffler body l shown in Figures 1 and 2 reaches a high temperature of 300 to 400°C or higher, silicone, which has extremely good heat resistance, can be used as the material for the muffler body l. It is also recommended to use resins or thermosetting polycarbodiimide resins.

The above-mentioned heat-resistant resin is a heat-resistant resin to which an inorganic substance is added in order to reduce the cost of manufacturing the silencer and to improve heat resistance and heat dissipation.

A typical example of the above inorganic material is alumina (A1203)
, beryllia (BeO), cesium oxide (Ce07), magnesia (MgO), silica (SiO,), quartz (S
tOt), titania (Tio, ), zirconia (Z
r 02), mullite (3A1.O, -28iO7
), spinel (M g O-A I to s), cordierite (2M g 0 ・2 A 1 t O3 ・5
S 1O7), silicon carbide (SiC), titanium carbide (T i C), boron carbide (B, C), tungsten carbide (WC), graphite (C), boron nitride (
BN), silicon nitride (Si3N4), aluminum titanate (AIT i 03), mica ceramics (muscovite, sericite, etc.), sepiolite, pyrophyllite, steatite (MgO-8jO2), forsterite (2Mg O・5ift), zircon (Z
r Ot ・S i Ot ), cordierite (
2M g 0・2A1. Ceramics such as O, .5SiOt), etc. are recommended, but glass wool, glass fiber, glass cloth, asbestos cloth, carbon fiber, etc., which are usually called reinforcing materials, can also be used. The present invention is not necessarily limited to the above-mentioned inorganic materials. These minerals may be used alone or in combination. In the present invention, in order to improve the strength of the silencer, it is particularly preferable to use ceramics and reinforcing materials among the inorganic materials.

As described above, the present invention is characterized in that the muffler body 1 is made of at least one kind of inorganic substance 7 and a heat-resistant resin, and the concentration of the inorganic substance 7 is in the vicinity of the inner wall surface 1a of the muffler body 1, that is, in the vicinity of the surface in direct contact with the exhaust gas. It is characterized by providing a concentration gradient which is highest and gradually decreases from the inner wall surface 1a toward the outer wall surface 1b. According to such a configuration, oxidative deterioration of the muffler body 1 due to the high heat of exhaust gas is suppressed only in the vicinity of the inner wall surface 1a of the muffler body l, and the inner wall surface 1a and the outer wall surface l where the concentration of inorganic substance 7 is low.
The temperature difference between the outer wall surfaces 1b and 1b becomes larger, and a noise silencing effect occurs near the outer wall surface 1b.

The amount of the inorganic substance 7 added near the inner wall surface 1a of the muffler body 1 is preferably 100 parts by weight or more and 500 parts by weight or less based on 100 parts by weight of the heat-resistant resin, and furthermore, the amount of the inorganic substance 7 added near the outer wall surface 1b of the muffler body 1 is preferably 100 parts by weight or more and 500 parts by weight or less with respect to 100 parts by weight of the heat-resistant resin. The amount of inorganic substance 7 added is preferably 30 parts by weight or more and 300 parts by weight or less based on 100 parts by weight of the heat-resistant resin.

When the amount of the inorganic substance 7 added near the outer wall surface 1b is more than 300 parts by weight, the temperature difference between the inner wall surface 1a and the outer wall surface 1b is small, especially when the temperature of the engine exhaust gas is as high as 350°C or higher. There is no temperature range between the inner wall surface 1a and the outer wall surface 1b that matches the Tg point of the heat-resistant resin, and a sufficient sound damping effect cannot be obtained. Heat-resistant resin has much better corrosion resistance than carbon steel or stainless steel against acids, salts, and various corrosive substances, so it is highly resistant to corrosive substances contained in exhaust gas or in the outside air. It is possible to prevent corrosion of the muffler body l due to salt and the like.

The specific gravity of the muffler body l shown in Figures 1 and 2 varies depending on the amount of inorganic material 7 added, but the specific gravity is approximately 1.
．． It is within the range of 5 to 3, and the weight of the muffler body 1 can be reduced compared to a muffler made of carbon steel or stainless steel.

That is, when the material of the muffler body 1 is a heat-resistant resin, the thickness is preferably 1 to 10 cm, more preferably 0.5 to 5 ffx. If the thickness exceeds 1Qxx, it is not possible to reduce the weight of the muffler, and if it is less than 1111, the physical strength of the muffler during high-temperature loads decreases, and the muffler body 1 may be damaged by external impact. In addition to the disadvantage that the muffler body 1 may be deformed, the inner wall surface 1a and the outer wall surface 1b of the muffler body 1
The temperature difference between the two ends up becoming smaller, resulting in a reduction in sound-dampening performance.

Various specific examples of the silencer using the heat-resistant resin will be described below according to the operating procedures thereof.

[Operation 1] Preparation of engineered poxy resin mixture Bisphenol F type liquid epoxy resin (Ebicoto'
807: Nadic anhydride (Kayano\do MC), which is an acid anhydride curing agent, to 100 parts by weight (manufactured by Ciel Kagaku KK)
D: manufactured by Nippon Kayaku KK), 2 parts by weight of 2-ethyl-4-imidazole as a curing accelerator, and sericite as an inorganic substance to prepare an epoxy resin mixture. The amount of inorganic substances added was 70 parts by weight as shown in Table 1.
Four types of mixtures with different concentrations were prepared, each containing 100 parts by weight, 200 parts by weight, and 300 parts by weight.

Table 1 (Note 1) Diglycidyl ether of bisphenol F Epoxy equivalent 170-190 Manufactured by Shell Chemical KK (Note 2
) Nadic anhydride manufactured by Nippon Kayaku KW [Operation 2]
Preparation of epoxy resin prepreg The resin mixture shown in Table 1 was treated with aminosilane to a thickness of 0.5 x m.
Vertical 300311. After coating and impregnating a glass cloth with a width of 630xx, it was heated and cured at 100° C. for 3 hours to create four types of epoxy resin prepregs with different sericite concentrations.

[Operation 3] Creating a muffler body made of engineered poxy resin The four types of prepregs created in [Operation 2] above were coated with a silicone wax release agent on the surface in order from the one with the highest inorganic concentration. Wrap it around a pipe and press it from the outside with a pressure of 97 ctn" or more at 120°C for 12 hours, then at 150°C.
The muffler body 1 (sample 2) substantially similar to that shown in FIG. 1 was prepared by heating and curing for 3 hours.

[Operation 4] Preparation of diallyl terephthalate resin mixture Dissolve 100 parts by weight of diallyl terephthalate oligomer in 100 parts by weight of a mixed solvent in which the mixing ratio of methyl isobutyl ketone and toluene is 1=1 by weight, and use this solution. Three types of diallyl terephthalate resin mixtures having different inorganic concentrations shown in Table 2 were prepared.

Table 2 [Operation 5] Creation of diallyl terephthalate resin prepreg The mixture shown in Table 2 was applied and impregnated onto a 0.5 iz thick, 30011 x 630 III jI glass cloth whose surface had been treated with vinyl silane, and was heated at 800°C for 50 minutes. The mixture was heated for a minute to create three types of diallyl terephthalate resin prepregs with different concentrations of sericite.

[Operation 6] Creation of a muffler body made of diallyl terephthalate resin By the same operation as in [Operation 3] above, heat curing was performed at 100°C for 1 hour and then at 130°C for 1 hour to form a muffler body made of diallyl terephthalate resin ( Sample ■) was created.

[Operation 7] Adjustment of phenolic resin mixture For 100 parts by weight of resol type face resin (BH3-330 manufactured by Showa Kobunshi KK), the mixing ratio of silica and sericite is 1 by weight.
:1 mixture was mixed at the ratio shown in Table 3 to prepare five types of phenolic resin mixtures having different inorganic concentrations.

Table 3 [Operation 8] Creation of phenolic resin prepreg The mixture shown in Table 3 was treated with aminosilane to a thickness of 0.2
A glass cloth measuring 3001 m long and 630 m wide was coated and impregnated, and heated at 100° C. for 10 minutes to create 5 types of phenolic resin prepregs with different concentrations of silica and sericite mixtures.

[Operation 9] Creating the muffler body made of phenolic resin [
A phenolic resin muffler body (sample ■) was prepared by heating at 180°C for 1 hour in the same manner as in Operation 3].

[Operation 10] Creation of epoxy resin premix Add DD as a hardening agent to 100 parts by weight of bisphenol A epoxy resin (Epicote 828, manufactured by Shell Chemical KK).
50 parts by weight of M (4,4′-diγminolaphenylmethane).

1 part by weight of DMP-30 as a hardening accelerator and 2 parts by weight as a reinforcing material and 150 parts by weight of short glass fibers whose surface was treated with aminosilane were added with sericite as an inorganic material in the proportions shown in Table 4, and then heated at 40°C. Knead the mixture well using a roll until it becomes homogeneous, then roll it into a 0.9 x
xx, a sheet-like epoxy prepreg with a width of 630 mg was prepared.

Table 4 [Operation 11] Creation of engineered poxy resin muffler body [
120°C for 2 hours at 80°C by the same operation as Step 3].
The muffler body (sample 2) made of epoxy resin was prepared by heating at 150° C. for 6 hours and then at 150° C. for 3 hours.

[Comparative Example 1] Using an epoxy resin mixture having the composition shown in Not in Table 1, and using four sheets of prepreg prepared in the same manner as in [Step 2] above, epoxy resin was prepared using the method in [Step 3] above. A resin muffler body (sample ■) was created.

[Comparative Example 2] Using an epoxy resin mixture having the composition shown in No. 4 in Table 1, and using four sheets of prepreg prepared in the same manner as in [Operation 2] above, epoxy resin was prepared using the method in [Operation 3] above. A resin muffler body (sample ■) was created.

[Comparative Example 3] In the above [Operation 1], the blending amount of sericite was changed to 100
An epoxy resin mixture was obtained in the same manner as [Operation 1] except that the amount was 0 parts by weight. Using this mixture, perform the procedure described above in [Operation 2].
] A prepreg was made using a method similar to that used in [2], but the viscosity of the mixture was high, so it had poor impregnation into glass cloth.
In addition, the epoxy resin muffler body (sample ■) molded using four sheets of this prepreg had low impact resistance and was damaged when the molded product was dropped from a height of 1 m.

[Operation 12] Durability test of each of the above samples Each sample was mounted 200 cm from the exhaust pipe outlet of an air-cooled 4-cylinder gasoline engine (Honda G-200) and subjected to high-speed, high-load operation (4000 rpm, 1000 hours). A test was conducted. The results are shown in Table 5.

Table 5 (Note) ○ indicates better performance than commercially available steel plate mufflers.

According to Table 5, the stone silencer of the present invention (sample ■■■■
) was found to be superior to the comparative muffler (sample ■■■) in terms of muffler performance, appearance, and strength of the muffler body.

Effects of the Invention As explained in detail above, the silencer using heat-resistant resin according to the present invention allows exhaust gas generated from an internal combustion engine to pass sequentially from the man-powered pipe attached to the muffler body to the output pipe,
In a muffler designed to muffle exhaust noise caused by an explosion of an internal combustion engine, the muffler body is made of at least one inorganic substance and a heat-resistant resin, and the concentration of the inorganic substance is highest near the inner wall surface of the muffler body, Since the structure is such that a concentration gradient is provided that gradually decreases from the inner wall surface toward the outer wall surface, the following effects are brought about. That is, since the muffler body is manufactured using a mixture of a heat-resistant resin and an inorganic material, which itself has a sound-absorbing effect, noise can be efficiently absorbed. In particular, the sound absorption characteristics of the muffler are not limited to a predetermined region, and a wide range of sound absorption characteristics can be obtained. Furthermore, it becomes possible to absorb airflow noise within the muffler that is generated when the high-speed exhaust flow collides with the wall surface of the muffler body. Furthermore, due to the corrosion resistance of the heat-resistant resin, corrosion of the muffler body over time does not occur, and the weight of the muffler body itself can be reduced. Furthermore, since there is no need to attach a sound absorbing material such as glass wool or asbestos to the inside of the muffler body, there is no dust dissipated into the air during use, and there is an advantage that no pollution is generated.

In addition, in the case of the present invention, a concentration gradient is provided such that the concentration of the inorganic substance is highest near the inner wall surface of the muffler body and gradually decreases from the inner wall surface toward the outer wall surface. The oxidative deterioration of the muffler main body is limited only to the vicinity of the inner wall surface of the muffler main body, and the temperature difference between the inner wall surface and the outer wall surface where the concentration of inorganic substances is low becomes large, so that a noise silencing effect occurs near the outer wall surface. Furthermore, even when the exhaust gas temperature becomes extremely high, the heat resistance of the muffler body can be further increased, protecting the muffler body from high temperatures and maintaining the original function of the muffler for a long time. It becomes possible to maintain the engine and reduce NOx and H.
It is also possible to sufficiently cope with the increase in temperature of exhaust gas caused by exothermic reactions when a three-way catalyst is attached to reduce pollutants such as C (hydrocarbon) and CO.

Furthermore, since the muffler itself is extremely lightweight, it is advantageous when installed in automobiles, etc., and the internal structure of the muffler can be simplified, contributing to cost and fuel cost reductions. I can do it.

[Brief explanation of the drawing]

Figure 1 shows a first example of a silencer using heat-resistant resin according to the present invention.
FIG. 2 is a sectional view of a main part showing a second embodiment of the present invention. ■...Muffler body, ■a...Inner wall surface, Ib...
Outer wall surface, 2...Input tube, 3...Output tube, 4.5...
・Mirror plate, 6... Reinforcement material, 7... Inorganic material, 8... Collision plate, Figure 1 Figure 2 Figure 6 Collision plate °l

Claims (3)

[Claims] (1) A muffler that muffles exhaust noise caused by an explosion of the internal combustion engine by passing exhaust gas generated from an internal combustion engine sequentially from an input pipe attached to a muffler body to an output pipe, wherein the muffler body is made of inorganic material. and a heat-resistant resin, and characterized in that the concentration of the inorganic substance is highest in the vicinity of the inner wall surface of the muffler body, and is provided with a concentration gradient such that it gradually decreases from the inner wall surface toward the outer wall surface. A silencer made of heat-resistant resin. (2) The heat-resistant resin is at least one thermosetting resin selected from epoxy resins, phenolic resins, silicone resins, unsaturated polyester resins, diallyl phthalate resins, melamine resins, and thermosetting polycarbodiimide resins. Claim No. (1) characterized in that
A silencer using the heat-resistant resin described in Section 1. (3) The heat-resistant resin is at least one thermoplastic resin selected from polyamide resin, polyester resin, polyphenylene sulfide resin, thermoplastic fluororesin, polysulfone resin, and polyphenylene ether resin. A silencer using a heat-resistant resin according to claim (1).