JPS6115498A - Sound diaphragm - Google Patents

Abstract

PURPOSE:To strengthen binding of carbon fiber and binder, reduce distortion remarkably and obtain very excellent quality of sound by constituting a sound diaphragm mainly of carbon fiber and a binder devoid of fibrous structure. CONSTITUTION:For instance, 100pts.wt. of carbon fiber, 6-10mum in fiber diameter, and 0.1-2cm in fiber length, is dispersed in water, and about 50-100pts.wt. of water soluble organic binder devoid of fibrous structure is added and agitated to fabricate it in water. Then, aluminum sulfate is added and adjusted to pH4- 6, and about 1-10pts.wt. of sizing agent is added and agitated. Immediately after agitation, a mat is manufactured using a wire cloth of desired shape of a diaphragm. The wet carbon fiber mat taken out from the wire cloth is heat press dried at die temperature of 140-200 deg.C and pressing time of 3-15min, and a sound diaphragm is obtained. Thus, as shown by frequency characteristic given by solid lines, distortion is remarkably reduced compared with conventional diaphragms (dotted lines).

Description

【発明の詳細な説明】 〔産業上の利用分野〕 本発明は、音響振動板に関するものである。[Detailed description of the invention] [Industrial application field] The present invention relates to an acoustic diaphragm.

〔従来技術とその問題点〕[Prior art and its problems]

従来よシ音響振動板の構成素材の一つとして炭素繊維が
用いられている。Conventionally, carbon fiber has been used as one of the constituent materials of acoustic diaphragms.

例えば、フリーネス３００　ｃｃ以下の叩解度としたパ
ルプにヤング率１５０００Ｋｇ／ｍ”以上の炭素繊維を
混抄してなる電気音響機器用振動板が提案されている（
特公昭５４−３３１３０号）。For example, a diaphragm for electroacoustic equipment has been proposed that is made by mixing carbon fiber with a Young's modulus of 15,000 Kg/m" or more into pulp with a freeness of 300 cc or less (
Special Publication No. 54-33130).

又、パルプ繊維と３０００〜１５０００　ＫＶ／ｍｍ（
Ｄヤング率を有する炭素繊維とを含分、前者のパルプ繊
維と後者の炭素繊維との間の重量割合は前者が１０〜４
０％、後者が９０〜６０ｑ６であるスピーカ用振動板も
提案されている（特公昭５６−４７７５７号）。In addition, pulp fiber and 3000 to 15000 KV/mm (
The weight ratio between the former pulp fiber and the latter carbon fiber is 10 to 4.
0%, and a speaker diaphragm in which the latter is 90 to 60q6 has also been proposed (Japanese Patent Publication No. 56-47757).

ところが、これらの振動板はバインダーとして用いられ
ている物質がパルプであることより、炭素繊維同士の結
合が弱く、この為強度、剛性及び内部損失の面で問題が
残されておシ、歪が比較的大きく充分に良好な周波数特
性のものであるとは言えない。However, since the material used as a binder in these diaphragms is pulp, the bond between the carbon fibers is weak, and as a result, problems remain in terms of strength, rigidity, and internal loss, resulting in distortion. It cannot be said that it is relatively large and has sufficiently good frequency characteristics.

〔問題点を解決する為の手段〕[Means for solving problems]

音響振動板を、主として炭素繊維と繊維構造をもたない
バインダーとで構成する。The acoustic diaphragm is mainly composed of carbon fibers and a binder having no fiber structure.

素繊維１００重量部を水に分散させ、これに水中で抄造
する為に水溶性有機質で繊維構造をもたないバインダー
、例えば水溶性アクリルアマイド樹脂（アニオン系樹脂
で分子量８０万〜１００万）約５０〜１００重量部を添
加して攪拌する。100 parts by weight of elementary fibers are dispersed in water, and in order to form the paper in water, a water-soluble organic binder without a fiber structure, such as a water-soluble acrylamide resin (an anionic resin with a molecular weight of 800,000 to 1,000,000), is added. Add 50 to 100 parts by weight and stir.

次に、硫酸バンドを添加してｐＨ４〜６　に調整し、こ
れにサイズ剤を約１〜１０重量部添加して攪拌し、その
後直ちに所望の振動板形状の抄網にて抄造する。Next, sulfuric acid is added to adjust the pH to 4 to 6, and about 1 to 10 parts by weight of a sizing agent is added thereto and stirred. Immediately thereafter, paper is made using a paper mesh having the desired shape of a diaphragm.

そして、抄網よシ外した湿潤炭素繊維マットを、金型温
度１４０〜２００℃１．プレス時間３〜１５分の条件で
熱プレス乾燥して、本発明になる音響振動板を構成する
。Then, the wet carbon fiber mat, which had been removed from the paper screen, was heated to a mold temperature of 140 to 200°C. The acoustic diaphragm of the present invention is constructed by hot press drying under conditions of a pressing time of 3 to 15 minutes.

尚、このようにして構成された音響振動板は、炭素繊維
１００重量部に対して繊維構造をもだないバインダーが
約３０〜５０重量部の組成となっている。The acoustic diaphragm thus constructed has a composition of about 30 to 50 parts by weight of a binder that does not have a fiber structure to 100 parts by weight of carbon fibers.

このような炭素繊維と繊維構造をもたないバインダーと
で構成された音響振動板は、炭素繊維が振動板としての
特性上望ましい伝播速度の大きなものであり、又、バイ
ンダーとして用いたものは繊維構造をもたないものであ
るので、炭素繊維の交鎖部分において結合がほとんどな
されないといった欠陥を引き起こすことのないものであ
シ、全体として充分均質な強度が得られ、剛性も高く、
さらには歪特性も減少したものとなり、好ましい特性を
示す。Such an acoustic diaphragm composed of carbon fibers and a binder without a fiber structure has a high propagation velocity, which is desirable due to the characteristics of carbon fibers as a diaphragm. Since it has no structure, it does not cause defects such as almost no bonding at the cross-linked portions of carbon fibers, and it has sufficient uniform strength as a whole, and has high rigidity.
Furthermore, the strain characteristics are also reduced, showing favorable characteristics.

例えば、゛図面に本実施例の音響振動板を用いたスピー
カの周波数特性を実線で、従来のパルプと炭素繊維の混
抄による音響振動板を用いたスピーカの周波数特性を点
線で示す如く、比較例のものでは高域限界周波数が１０
ＫＨｚであるのに対し本実施例のものでは高域限界周波
数が１８ＫＨｚ　　と大巾に伸びており、又、中域の第
２高調波歪も平均して約６ｄＢ減少しているといつだよ
うに極めて優れている。For example, in the drawing, the frequency characteristics of a speaker using the acoustic diaphragm of this example are shown by a solid line, and the frequency characteristics of a speaker using a conventional acoustic diaphragm made of a mixture of pulp and carbon fiber are shown by a dotted line. The high limit frequency is 10
KHz, whereas in this example, the high-frequency limit frequency has been significantly extended to 18 KHz, and the second harmonic distortion in the mid-range has also decreased by about 6 dB on average. It is extremely excellent.

さらには、この音響振動板は、従来の天然パルプを用い
た場合と同様な製造工程で作れるものであり、成形性及
び量産性に富んでおり、しかも難燃性であるといった特
長も有している。Furthermore, this acoustic diaphragm can be made using the same manufacturing process as conventional natural pulp, has excellent moldability and mass productivity, and is also flame retardant. There is.

〔効果〕〔effect〕

適度な内部損失を有するもので、かつ剛性は大きく、し
かも充分な強度を有しておシ、高域限界周波数は大巾に
従来のものよシ伸び、又、歪も大巾に低減され、極めて
優れた音質の得られるものである。It has a moderate internal loss, high rigidity, and sufficient strength.The high frequency limit is much longer than that of conventional products, and the distortion is also greatly reduced. This provides extremely excellent sound quality.

又、製造も従来の手法をそのまま採用でき、極めて簡単
かつ低コストで得られる。Moreover, the conventional method can be used for manufacturing as is, and it can be obtained extremely easily and at low cost.

【図面の簡単な説明】[Brief explanation of drawings]

図面は、スピーカの周波数特性のグラフである。 The drawing is a graph of the frequency characteristics of the speaker.

Claims (1)

【特許請求の範囲】[Claims] 主として炭素繊維と繊維構造をもたないバインダーとで
構成したことを特徴とする音響振動板。An acoustic diaphragm characterized by being mainly composed of carbon fiber and a binder having no fiber structure.