JPS62131696A - Loudspeaker diaphragm and manufacture of the same - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a speaker diaphragm and a manufacturing method thereof.

[Conventional technology]

Conventionally, as a speaker diaphragm, a cone-shaped molded product obtained by heating and press-molding a carbon fiber paper sheet impregnated with a thermosetting resin has been used. This method is similar to high-pressure press molding, and has the advantage that the amount can be adjusted.

[Problem that the invention seeks to solve]

However, when deep drawing is performed during pressure forming, or when a complex three-dimensional shape is created, the carbon fiber sheet may be damaged or the carbon fibers may flow in the deep drawing area, resulting in uneven fiber density. There was a problem. In addition, during post-processing of the molded product, such as trimming after pressing and finishing of edges, since the above-mentioned paper sheet is made of short fibers,
It also has the problem of being relatively brittle and prone to breakage and cracking at cut points.

The present invention is intended to solve the above-mentioned problems and provides a speaker diaphragm that has a uniform areal density and is free from cracking during post-processing.

[Means for solving problems]

In order to obtain a diaphragm suitable for the above purpose, the present inventors
As a result of various studies, we found that if we use a prepreg made of a carbon fiber paper sheet impregnated with a thermosetting resin and a woven fabric made of inorganic or organic continuous fibers attached to one or both sides, it would be possible to deeply We have discovered that even when shaped into a drawn shape or a three-dimensionally complex shape, it does not break or the fiber density becomes uneven, and it is possible to obtain a molded product that is less prone to breakage during post-processing. .

That is, the speaker diaphragm of the present invention is composed of a laminate of a carbon fiber paper sheet impregnated with a thermosetting resin and a continuous fiber woven fabric adhered to one or both sides of the sheet before molding, The woven fabric is characterized in that the mesh (q) is less than or equal to the areal density of the material sheet.

In addition, the method for producing a carbon fiber paper sheet of the present invention involves attaching a continuous fiber woven fabric having a basis weight less than or equal to the areal density of the paper sheet to one or both sides of a prepreg obtained by impregnating a thermosetting resin. , which is characterized by heating and pressurizing it into a predetermined shape.

[For production]

The carbon m-fiber sheet used in the present invention is a mat obtained by forming short m-fibers, and the thermosetting resin for impregnation includes epoxy resin, phenol resin, diallyl phthalate resin,
Unsaturated polyester resins, urethane resins, epoxy acrylate resins, etc. are suitable, and epoxy resins are common, and are impregnated into the above-mentioned paper sheet to form a prepreg.

The woven fabric made of inorganic or organic continuous fibers used in the present invention has a small basis weight and a woven fabric so as not to impair the excellent properties of the carbon fiber sheet as a diaphragm, such as the high specific modulus of elasticity. A densely woven fabric is desirable. For example, if a roving with a small diameter is used, a woven fabric with a small basis weight and a high weave density can be obtained. If a woven fabric with a large basis weight is used, it becomes difficult to obtain uniform bending rigidity, so the basis weight of the woven fabric must be equal to or less than the areal density of the carbon fiber paper sheet.

In addition, the above-mentioned continuous 1@female is required to be fireproof enough to withstand the temperature during heat and pressure molding and not be affected by thermosetting resin, so woven fabrics that meet these conditions include carbon fiber, glass, etc. Particularly preferred are fibers and aramid fibers in plain weave, satin weave, twill weave, etc. These woven fabrics are attached to the above-mentioned prepreg and have the effect of preventing the carbon fibers from flowing in the squeezed portion during heating and pressure molding.

Although the present invention is primarily aimed at improving moldability, the elastic modulus, internal loss, density, etc. of the molded article can be adjusted by appropriately selecting the type, basis weight, and weaving density of the woven fabric. Further, the carbon m-fiber sheet may be made of either high-strength carbon fiber or high-modulus carbon fiber, but preferably one made of high-modulus carbon Fa# is suitable and convenient for high-temperature applications.

〔Example〕

Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example 1 High elasticity with areal density of 30 g/m' (35-40 t/mm'
) Aral dye on carbon fiber mat) 100 parts of GY260 (bisphenol A type epoxy resin manufactured by Jiki Ciba Geigy Co., Ltd.), 10 parts of dicyandiamide, 2-ethyl-4
- Impregnated with a resin solution consisting of 4 parts of methylimidazole and 20 parts of acetone and dried at a temperature of 50°C for 30 minutes, with an areal density of 50 g/m' (matte 30 g/rn', resin 20 g/m').
m'), a circular prepreg with a diameter of 15 cm was obtained.

Two such prepregs were prepared, and one prepreg was coated with 1ti plain weave glass fabric with a mesh size of q20g/m2 on one side, and the other was made into a prepreg and both were heated in a mold at 150°C at 50Kg/m2. A cone-shaped diaphragm was obtained by heating and pressing at crn' for 30 minutes. In the case where glass fiber was attached to one side, the prepreg had a uniform surface density, and even when the molded product was trimmed, there was no cracking, and post-processing was easy.

- On the other hand, when the glass woven fabric was not attached, cracks were more likely to occur at the cut part during trimming. Also, the dynamic elastic modulus of both was 2 x 10"dynes/cm'
The elastic modulus of the prepreg was not impaired by the adhesion of the woven fabric.

Example 2 100 parts of Araldye) GY260 and 10 parts of dicyandiamide were applied to a high-strength carbon fiber paper sheet with an areal density of 28 g/m'.
1 part, 3 parts of 3-('P-chlorophenyl)-1,1-dimethylurea, and 20 parts of acetone, and dried for 20 minutes at a temperature of 50°C to obtain an areal density of 50 g/m'.
A circular prepreg with a diameter of 15 cm was obtained.

Two sheets of prepreg like this are prepared, one side of which is covered with a plain glass woven fabric with a basis weight of 20 g/m', and the other prepreg is held at 3° in a mold.
A cone-shaped diaphragm was obtained by heating and pressing at C150Kg/crrf for 30 minutes. In the case where glass fiber was attached to one side, the prepreg had a uniform areal density, and even when the molded product was trimmed, no cracking occurred, and post-processing was easy. On the other hand, when the glass fabric was not attached, cracks were likely to occur at the cut portion during trimming. In addition, the dynamic elastic modulus of both is 1.5 to 1.6 x 1011 dynes/
In crn', the elastic modulus of the prepreg was not impaired by the adhesion of the woven fabric.

〔Effect of the invention〕

As described above, the diaphragm of the present invention prevents the flow of carbon MIt fibers during molding by attaching a woven fabric made of continuous fibers to a resin-impregnated carbon fiber sheet to prepreg before molding. The areal density distribution of the molded product is maintained uniformly, so the vibration characteristics of the speaker are not impaired.

Further, the method of the present invention can be applied as is to existing manufacturing processes, and there is no cracking during post-processing as in the conventional method, which has the effect of improving productivity.

Patent applicant Civer-Geigy Akchengesellschaft Asahi Kasei Corporation

Claims (2)

[Claims] (1) A carbon fiber paper sheet impregnated with a thermosetting resin,
A diaphragm for a speaker, comprising a laminate with a continuous fiber woven fabric adhered to one or both sides of the sheet before molding, and wherein the fabric has a basis weight that is less than or equal to the areal density of the material sheet. . (2) After pasting a continuous fiber woven fabric having a basis weight equal to or less than the areal density of the paper sheet on one or both sides of a prepreg obtained by impregnating a carbon fiber paper sheet with a thermosetting resin,
A method for manufacturing a speaker diaphragm, which is characterized by heating and pressurizing it into a predetermined shape.