JPS5913498A - Diaphragm for speaker - Google Patents

Abstract

PURPOSE:To provide a speaker diaphragm with improved high frequency resonance frequency and frequency characteristics by forming a composite film obtained by composing mica with polyether aromatic keton resin consisting of aromatic dihalide or resin mainly consisting of polyether aromatic keton. CONSTITUTION:Polyether aromatic keton resin consisting of hydroquinone and 4,4'-diharobenzophenone is used as diaphragm forming resin and phlogopite mica having a molecular formula KMg3(AlSiO3O10).(OH)2 is used as the mica. In a composite film obtained by composing said resin with 30wt% mica, the elastic modulus is 51.000(kg/cm<2>) and the internal loss is 0.018. Since the acoustic characteristics (a) of a speaker using the diaphragm has higher elastic modulus than the acoustic characteristics (b) using a diaphragm consisting of a polyethylene terephthalate film having the same diameter and thickness, the high frequency resonance frequency fH is increased. Conseqently, a speaker of which high-pitched tone reproducing is effective and frequency characteristics are improved by reducing the variation is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to plastics, particularly bisphenols such as nohydroquinone, and ketones such as 4,4'-difluorobenzophenone in which two norogen atoms are in the ortho or para position. The present invention relates to a speaker diaphragm molded from a polyether slightly aromatic ketone type resin made of an aromatic di-ride activated by a group or a resin consisting entirely of polyether aromatic keto.

Conventional Structure and Problems Conventionally, polyethylene terephthalate film has been used as a speaker diaphragm made of plastic.

However, polyethylene terephthalate has a small elastic modulus, and in the case of a full-range speaker, the high resonant frequency fH
There was a problem that the treble reproduction was not necessarily good.

OBJECTS OF THE INVENTION The present invention is intended to eliminate all of the above-mentioned drawbacks, and it is an object of the present invention to provide a diaphragm for a speaker that has a high high-frequency resonance frequency fH and poor frequency characteristics.

Structure of the Invention The speaker diaphragm of the present invention is made of bisphenols such as hydroquinone and aromatic cybarides such as 4,4'-difluorobenzophenone in which two halogen atoms are activated by a ketone group at the ortho or para position. A composite film is formed by combining polyether aromatic ketone type resin or resin mainly composed of polyether aromatic ketone with a moderate amount of mica such as muscovite (muscovite) and phlogopite (phlogopite). This composite film has an elastic modulus of 32.000-90.000 (Kg/cm
) t? This is extremely large compared to 19,000 (Kti/crl) for polyethylene terephthalate film. Since the speaker diaphragm completely formed from the twisted composite film has a high elastic modulus, the high-frequency resonance frequency f)1 is high, and the diaphragm can be used to reproduce high-pitched sounds. Further, the internal loss of the composite film is 0.015 to 0.026, which is compared to 0.005 of the polyethylene terephthalate film.
Because it is five times larger, a diaphragm made of this material has less so-called power fluctuation in frequency characteristics and less distortion.The above composite film also has a heat distortion temperature of around 1600, and exhibits vague heat resistance. Moreover, in flame resistance tests, the diaphragm molded with this composite film is self-extinguishing, so it can withstand high temperatures and is flame retardant.Therefore, it is the best diaphragm for speakers that require heat resistance and flame resistance. Obtainable.

Description of Examples [Example 1] A polyether aromatic ketone type resin consisting of hydroquinone and 4,4'-dihalobenzophene having the structure shown below was used as the resin for molding the diaphragm, and mica was phlogovite ( Phlogopite) based mica, molecular formula KM93 (AI
Si301o).(○H)2 was used. The elastic modulus of a composite film made by combining the above resin with mica at a weight ratio of 30% is 5.
1,000 (Kg/'aI), internal loss is 0.
018 and 9 The above composite film was molded into a diaphragm using a pressure forming method, and the diameter was 40 mm.

A cone-shaped diaphragm with a thickness of 80 μm was obtained. Figure a shows the acoustic characteristics of a speaker using this diaphragm, and figure b shows the acoustic characteristics of a speaker using a diaphragm made of polyethylene terephthalate fill having the same diameter and thickness. As is clear from the figure, since the speaker using the composite film diaphragm of this example has a high elastic modulus, the high-frequency resonance frequency fH becomes high, and high-frequency sound reproduction is improved. Moreover, because the internal loss is large, the frequency characteristics are so-called "wavering."

This results in a speaker with a small frequency response and smooth frequency characteristics.

[Example 2] The weight L of the resin shown in Example 1 and mica was reduced to 1.
o% of the composite film is 32.000 (Kr
/Cn), and the internal loss was 0.015. A speaker in which the composite film was molded into a diaphragm in the same manner as in Example 1 had better high-frequency sound reproduction and excellent frequency characteristics with less vibration than a diaphragm made of polyethylene terephthalate film. .

[Example 3] The elastic modulus of a composite film prepared by setting the weight ratio of mica to the resin shown in Example 1 to 90 parts was 90.000 (Kq/
') + Internal loss was ○, o25. Example 1
Similarly, the speaker molded with the entire composite film diaphragm had better high-frequency sound reproduction than a diaphragm made of polyethylene terephthalate film, which was attributed to its frequency characteristics with less ``fluttering''.

Effects of the Invention As described above, according to the present invention, by using a composite film in which mica is combined with a polyether aromatic ketone type resin, there is an advantage that a speaker diaphragm with smooth frequency characteristics can be obtained.

[Brief explanation of the drawing]

The figure is a comparison diagram of the sound pressure frequency characteristics of the speaker diaphragm of the present invention and a conventional speaker diaphragm.

Claims (1)

[Claims] A polyether aromatic compound consisting of a bisphenol such as hydroquinone and an aromatic dino-ride such as 4,4'-difluoropenzophenone in which two 10 atoms are activated by a ketone group at the ortho or para position. A speaker diaphragm characterized by molding a composite film in which mica such as muscovite (muscovite) and phlogovite (phlogopite) is combined with a resin mainly composed of ketone type resin or polyether aromatic ketone.