JPH0247160B2 - ONKYOSHINDOBANNOSEIHO - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing an acoustic diaphragm, and more particularly to a method for manufacturing an acoustic diaphragm that can be deep drawn by pressure forming.

Conventionally, highly rigid polymers such as modified polyimide,
In particular, even if you try to press-form a composite film with whiskers, etc., due to its hardness, it is impossible to deep draw it, and there are limits to the shape of the diaphragm that can be applied. There is. There is also a method in which a polymer film that is easy to pressure mold is formed without using such a highly rigid polymer, and then a resin is applied and cured. However, this method has the disadvantage that it is difficult to uniformly apply the resin, and the properties of the resulting product are not constant. Furthermore, it is also possible to form a film using the resin itself without coating it on the base film, and then cure the film using ultraviolet rays, radiation, or heat; however, it is difficult to form a uniform film using the resin alone. Difficult to mold.

Therefore, the present invention provides a method for manufacturing an acoustic diaphragm that can be deep drawn by pressure forming.

The method according to the present invention comprises forming a resin layer made of a curable resin on a base film, molding it into a predetermined shape, and then curing it by applying radiation, ultraviolet rays, heat, or the like.

In this invention, as shown in FIG. 1, a material that can be easily pressure-molded is selected and used as the base film 1, and a resin layer 2 made of a curable resin is placed thereon.
form. The method for forming this resin layer is not limited to any particular method; for example, a gravure roll method, a doctor blade method, a brush coating method, a spraying method, etc. can be used as appropriate.

The resin that can be used in this invention may be any resin that can be cured when irradiated with radiation and/or ultraviolet rays or cured by heat to impart desired rigidity to the vibrating surface. The present invention is not limited to the following resins.
As such a resin, it is preferable to use, for example, a monomer or oligomer having an acrylic or methacrylic double bond. Among such monomers, those having an acrylate double bond include, for example, vinylprolidone, 2-ethylhexyl acrylate, lauryl acrylate, hydroxyethyl acrylate, ethoxyethoxy acrylate, tetrahydrofurfuryl acrylate, and Aronix M-5700 (trade name). Monofunctional monomers such as diethylene glycol diacrylate, tetraethylene glycol acrylate, neopentyl glycol diacrylate, Aronix M-6100 (trade name), etc.
Examples include polyfunctional monomers such as trimethylolpropane triacrylate, tetramethylolmethanetetraacrylate, dipentaerythritol hexaacrylate, and dipentaerythritol pentaacrylate. Examples of such monomers having a methacrylic double bond include those in which the acrylic double bond of the above-mentioned monomer is replaced by a methacrylic double bond. Furthermore, examples of resin species that form the skeleton having such double bonds include alkyd resins, polyesters, acrylic resins, polyurethanes, and epoxy resins. When an oligomer is used as the resin, it may be converted into an oligomer using a conventional method using the monomers described above.

It is preferable to use the above-mentioned resin together with a photosensitizer, and upon irradiation with light, the sensitizer decomposes to generate radicals, which polymerize and crosslink through the radicals. Such sensitizers include, for example,
Examples include benzoin compounds and benzophenone-amine mixtures. Examples of benzoin compounds include benzoin alkyl ethers, and examples of the alkyl group include methyl, isopropyl, n-butyl, and t-butyl.
Examples of amine compounds used in the benzophenone-amine mixture include methyldiethanolamine, triethanolamine, N-methylmorpholine, triethylamine, dibutylamine,
Examples include N,N-dimethylbenzylamine and N,N-dimethylaniline.

If necessary, reinforcing materials such as graphite and polyoxymethylene whiskers can be added to this curable resin to form a composite. The amount of the reinforcing material can be determined as appropriate, taking into consideration conditions such as curing speed and press moldability.

Note that if the film is opaque when coated with this curable resin, it is difficult for ultraviolet rays to pass through, so it is advantageous to use radiation.
In addition, in the case of transparency, any irradiation means may be used.

The molding material obtained as described above is, for example, pressure molded by a normal molding method to create a deep-drawn cone-shaped diaphragm, as shown in FIG. In this case, the vibrating part and the edge part do not need to be integrally molded.

Radiation,
For example, the resin layer is cured by irradiation with electron beams, gamma rays, or ultraviolet rays, or by applying heat.

The present invention will be further explained below with reference to Examples.

Example 1 A polyethylene terephthalate base film with a thickness of 12 microns was coated with a polyfunctional monomer, which is an ultraviolet curable resin (trade name "DPHA"; manufactured by Nippon Kayaku Co., Ltd.).
A coating layer was formed using a 1 mil doctor blade to a thickness of 25 microns. This resin layer was irradiated with ultraviolet rays with an intensity of 80 W/cm at a distance of 20 cm and a feed rate of 30 cm/min to soften and harden it. Note that this first stage irradiation may not be performed depending on the type of resin, coating means, etc.

The cured product obtained as described above was heated at 200°C.
A diaphragm for a dynamic microphone with a diameter of 30 mm was formed by air-pressure forming under a pressure of 8 kg/cm ² . After attaching a mask made by Shinchiyu to this,
Ultraviolet light with an intensity of 80W/cm, a distance of 20cm, and a feed rate of 5
It was hardened by irradiation at cm/min.

This diaphragm's f ₀ = 360 Hz and Q = 20, resulting in a well-defined and well-resolved sound quality.

Example 2 A polyethylene terephthalate film with a thickness of 12 microns was coated with an acrylate monomer (trade name "Aronix", manufactured by Toagosei Kagaku Kogyo Co., Ltd.), which is an electron beam curable resin, to a thickness of 25 microns using gravure. It was coated using the coat method. This coating layer was irradiated with an electron beam of 1.5 Mrad at a feed rate of 50 cm/sec to soften and harden it. Thereafter, pressure molding was performed at 200° C. and a pressure of 8 kg/cm ² to form a diaphragm for a dynamic microphone with a diameter of 30 mm. After attaching a mask made by Shinchiyu to this, a 5Mrad electron beam was applied at a feed rate of 50cm/
In seconds, it was irradiated and hardened.

This diaphragm showed similar results as in Example 1.

The advantages achieved by this invention are as follows. Firstly, when creating a cone-shaped diaphragm for a speaker, for example, by deep-drawing and press-molding conventionally used polymer films, it is necessary to use a ductile polymer film to obtain the desired shape. However, in this invention, a curable resin is uniformly applied to a ductile polymer film and then cured by applying radiation, ultraviolet rays, heat, etc., resulting in high-rigidity deep drawing. An acoustic diaphragm that can be press-formed has now been obtained. Second, when applying resin to a cone-shaped, dome-shaped, etc. diaphragm as in the past, uneven coating occurs, resulting in uneven product characteristics, but with this invention, the resin is evenly applied to the base film. By doing so, there is an advantage that a product with uniform characteristics can be obtained. Third, since radiation or the like is used, even opaque films made of composite resins such as graphite and whiskers can be cured in an extremely short time.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the structure of the material of this invention;
FIG. 2 is a cross-sectional view showing a state in which the diaphragm is molded into a cone-shaped diaphragm, and FIG. 3 is a cross-sectional view showing a hardening means for the diaphragm of FIG. 2. In addition, in the symbols used in the drawings, 1...base film, 2...resin layer.

Claims (1)

[Claims] 1. A method for manufacturing an acoustic diaphragm, which comprises press-molding a base film on which a resin layer made of a curable resin is formed, and then curing the resin layer with electron beams, ultraviolet rays, or heat.