Acoustics – Sound-modifying means – Muffler – fluid conducting type
Patent
1990-03-06
1992-04-28
Brown, Brian W.
Acoustics
Sound-modifying means
Muffler, fluid conducting type
181255, 181269, F01N 718
Patent
active
051079534
DESCRIPTION:
BRIEF SUMMARY
FIELD OF ART
The present invention relates to a muffler for muffling the exhaust noise from combustion engines such as automobiles.
BACKGROUND ART
It has heretofore been tried to produce mufflers using synthetic resins for overcoming the drawbacks of metallic mufflers such as heavy weight and corrosion. However, none of such synthetic resin mufflers are satisfactory yet. For example, a synthetic resin muffler reinforced by carbon fibers or glass fibers or a muffler having an outer shell formed of a synthetic resin is disclosed in Japanese Patent Laid-Open No. 75521/1980. But normal heat-resistant temperature of the synthetic resins proposed heretofore are lower than 150.degree. C. Besides, since these resins are thermosetting resins, it is impossible to adopt an efficient munufacturing method such as injection molding. Further, it is required as an essential condition to use a heat insulating material between such outer shell and an end member. In the event of heat transfer to the outer shell, the outer shell will be thermally deteriorated and no longer fulfil its function as a muffler.
DISCLOSURE OF THE INVENTION
Having therefore made extensive studies about a muffler of light weight and superior in heat resistance and service life to the conventional mufflers, the present inventors accomplished the present invention.
The present invention will be described in detail hereinunder. The present invention is concerned with a muffler characterized by having an outer shell formed of a thermotropic liquid crystal polymer.
The "thermotropic liquid crystal polymer" as referred to herein indicates a thermoplastic, meltable polymer which exhibits optical anisotropy when melted. Such a polymer which exhibits optical anisotropy when melted possesses the property that the molecular chains of the polymer in a melted state are arranged regularly in paralled. The property of the optical anisotropic melt phase can be confirmed by the conventional polarization test method using an orthogonal polarizer.
The thermotropic liquid crystal polymer is prepared from a monomer which is generally elongated, flat, highly rigid along the molecular long chain, and has a plurality of elongated chain bonds which are either coaxial or parallel.
The following are mentioned as component of the polymer which forms an optically anisotropic melt phase as mentioned above:
(A) at least one member selected from aromatic dicarboxylic acid compounds and alicyclic dicarboxylic acid compounds.
(B) at least one member selected from aromatic hydroxycaboxylic acid compounds;
(C) at least one member selected from aromatic diols, alicyclic diols and alicyclic diol compounds;
(D) at least one member selected from aromatic diols, aromatic thiophenols and aromatic thiolcarboxylic acid compounds;
(E) at least one member selected from aromatic hydroxyamines and aromatic diamine compounds.
These components may be used each alone, but in many cases used in combination like (A)-(C), (A)-(D), (A)-(B)-(D), (A)-(B)-(E), or (A)-(B)-(C)-(E).
As examples of aromatic dicarboxylic acid compounds (A1) are mentioned aromatic dicarboxylic acids such as terephathalic acid, 4,4'-diphenyldicarboxylic acid 4,4'-triphenyldicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1,4-naphathalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, diphenyl ether-4,4'-dicaboxylic acid, diphenoxyethane-4,4'-dicarboxylic acid, diphenoxybutane-4,4'-dicarboxylic acid, diphenylethane-4,4'-dicarboxylic acid, isophthalic acid, diphenyl ether-3,3'-dicarboxylic acid, diphenoxyethane-3,3'-dicarboxylic acid, diphenylethane-3,3'-dicarboxylic acid and 1,6-naphthalenedicarboxylic acid, as well as alkoxy- or halogen-substituted compounds thereof such as chloroterephthalic acid, dichloroterephathalic acid, bromoterephthalic acid, methylterephthalic acid, ethylterephthalic acid, methoxyterephthalic acid and ethoxyterephthalic acid,
As examples of alicyclic dicarboxylic acids (A2) are mentined such alicyclic dicarboxylic acids as trans-1,4-cyclohexanedicarboxylic acid, cis-4,4-cyclohexanedicarboxyl
REFERENCES:
patent: 3220507 (1965-11-01), Jettinghoff
patent: 4122914 (1978-10-01), Suyama
Kuroda Rikio
Shimizu Tetsuo
Brown Brian W.
Nippon Petrochemicals Co. Ltd.
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