JPS635959B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION In general, the first physical property condition required for acoustic components such as diaphragms of speaker heads and microphones, head shells of cartridges, cantilevers of tone arm cartridges, and cabinets of speakers is Young's. The ratio is high. If the Young's modulus is high, for example in a diaphragm, it is possible to drive the split vibration to a high frequency. Recently, in order to increase Young's modulus, attempts have been made to mix inorganic substances such as mica with thermosetting resins such as epoxy to form prepregs or molding compounds, which are then thermally cured to obtain acoustic components. However, this mica etc. has poor wettability with thermosetting resins such as epoxy as a binder, and the acoustic components manufactured using this are extremely brittle and have the disadvantage of low strength. There were some inconveniences that prevented me from performing to my full potential.

On the other hand, polyoxymethylene single crystal whiskers obtained by a method developed by the Institute of Textile and Polymer Materials, Agency of Industrial Science and Technology, Ministry of International Trade and Industry, have a Young's modulus of approximately 1×.
At 10 ¹¹ N/m ² , this polyoxymethylene single crystal whisker is as large as carbon fiber and has good wettability with a thermosetting resin binder such as epoxy. Furthermore, since this polyoxymethylene whisker has the shape of numerous needles protruding radially from one point, there is no directionality in the embedding properties of the composite with epoxy or the like.

The present invention relates to an acoustic component using such a polyoxymethylene whisker, and in particular, it is an object of the present invention to obtain an acoustic component with good acoustic characteristics that can fully utilize the physical characteristics of the polyoxymethylene whisker. .

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An acoustic component, such as a diaphragm for a speaker, according to the present invention will be described below with reference to the drawings, along with an example of its manufacturing method.

In this example, the thermosetting resin in container 1 is 1000 g of unsaturated polyester (manufactured by Dainippon Ink, trade name Polylite OD-R-489), 5 c.c. of methyl ethyl peroxide, and 10% cobalt naphthenate solution. Add 5 c.c. and add polyoxymethylene whisker 3.
Add 75g (7% by weight) and knead with mixer 4 without applying heat. The kneaded material is poured into a mold, etc., preheated, and the second
A prepreg sheet 5 is formed as shown in the figure.
This prepreg sheet 5 or premix is cured at 70° C. for 20 minutes using a heating compression molding machine 6 to form a speaker diaphragm.

The tensile Young's modulus of the diaphragm of the speaker according to this example was measured using a viscoelastic spectrometer and was found to be 4.87×10 ⁹ (N/m ² ). Compared to the Young's modulus of 2.85×10 ⁹ (N/m ² ) without adding 3, this is nearly twice as high. Also, polyoxymethylene whiskers 3 are added to the thermosetting resin in the same manner as above.
When the amounts of are 25g (2.4% by weight ⁾ and 50g ( ^4.8 % by weight), the Young's moduli of the ^diaphragm obtained by ² ) It was. In addition, as the thermosetting resin 2, an epoxy resin (manufactured by Ciel, trade name Epiyute) is used.
828) 50g made by Ciel, trade name Epiyute 1001 40g BF ₃ MEA 3.3g is used, and polyoxymethylene whisker 3 is added to this.
Add 2.8g (3% by weight) and knead with mixer 4 without applying heat. This kneaded material is poured into a mold or the like and preheated to form a prepreg sheet 5. In addition, this prepreg sheet 5 may also be used as a kneaded material as a premix.
Alternatively, premixes can be heated to 80°C using a heating compression molding machine 6.
C. for 2 hours and then cured at 160.degree. C. for 1 hour to form a speaker diaphragm.

The tensile Young's modulus of the diaphragm of the speaker according to this example was measured using a viscoelastic spectrometer and was found to be 3.77×10 ⁹ (N/m ² ). This is improved compared to the Young's modulus of 3.22×10 ⁹ (N/m ² ) without adding 3. Also, in the same manner as above, the above thermosetting resin 2
The amount of polyoxymethylene whiskers 3 to be added to
When the values are 1.0g (1.1% by weight) and 1.9g (2.1% by weight), the Young's modulus of the diaphragm obtained by these methods is 3.66.
×10 ⁹ (N/m ² ) and 3.73 × 10 ⁹ (N/m ² ).

This shows that the Young's modulus increases as the amount of polyoxymethylene whiskers 3 added to the thermosetting resin 2 increases. Therefore, a reinforced diaphragm can be obtained by using a thermosetting resin as a binder for polyoxymethylene whiskers. In addition, this polyoxymethylene whisker has good wettability with thermosetting resins such as unsaturated polyester and epoxy resin, and a strong diaphragm can be obtained. It can be fully demonstrated. Furthermore, since this polyoxymethylene whisker has the shape of numerous needles protruding radially from one point, the physical properties of the composite have no directionality, which is advantageous in terms of acoustic properties.

In the above example, polyoxymethylene whiskers and thermosetting resin were kneaded, and the kneaded product was then heat-molded as a prepreg or molding compound. and other fibrous substances or powders, etc., a mat is made from this mixture, the mat is impregnated with a thermosetting resin, coated with a spray, etc. to form a prepreg, and this is heated in a heating compression molding machine. It is easy to understand that the same effects as described above can be obtained even if the diaphragm of the speaker is obtained by hardening and molding.

In the above embodiments, the present invention was applied to the diaphragm of a speaker, but the present invention can also be applied to other acoustic components such as a cartridge headshell, a tone arm, a cartridge cantilever, and a speaker cabinet. Of course. It is easy to understand that even in this case, according to the present invention, an acoustic component with good characteristics can be obtained since the acoustic characteristics are excellent. Further, in the above embodiments, unsaturated polyester and epoxy resin were used as the thermosetting resin, but it goes without saying that other thermosetting resins such as phenolic resin can be used instead. Furthermore, it goes without saying that the present invention is not limited to the above-described embodiments, and can take various other configurations without departing from the gist of the present invention.

[Brief explanation of the drawing]

FIGS. 1, 2, and 3 are diagrams each showing an example of a method of manufacturing an embodiment of an acoustic component according to the present invention. 2 is a thermosetting resin, 3 is a polyoxymethylene whisker, and 5 is a prepreg sheet.

Claims (1)

[Claims] 1. An acoustic component characterized by being molded using a thermosetting resin as a binder for polyoxymethylene whiskers.