JPS6195698A - Diaphragm for speaker - Google Patents

Abstract

PURPOSE:To obtain a diaphragm having waterproofing and water resistance by impregnating, sticking and hardening an acrylic resin to a substrate made of a fiber, further installing a coat of an ultraviolet rays hardening type acrylic resin at the main surface of the substrate and maintaining an excellent acoustic characteristic. CONSTITUTION:A natural fiber, a chemical fiber or these mixtures 2 are beaten, dispersed in the suspension of the paper making tank, the paper making is executed with a desired diaphragm-shaped wire cloth, and after, the drying is executed under heating and pressure and the substrate is formed. Next, the substrate is impregnated to the liquid in which the acrylic resin is diluted with a solvent and the acrylic resin 3 is stuck to a fiber 2 which forms the substrate. After drying, a solution of the ultraviolet rays hardening type acrylic resin is stuck to the main surface of the substrate by the spraying and a coat 4 is formed. After that, the ultraviolet rays are irradiated and the coat 4 is fixed.

Description

[Detailed description of the invention] Technical field The present defense relates to a speaker imaging plate.

BACKGROUND ART In general, the performance required of a speaker diaphragm is that it is light, has a high Young's modulus, has a low density, and has a moderate internal loss so that good output sound pressure frequency characteristics of the speaker can be obtained. That's what I'm doing. In other words, the higher the Young's modulus and the lower the density, the higher the resonant frequency of the diaphragm, and the wider the piston movement area, the wider the frequency band of the speaker, and the greater the internal loss, the lower the split resonance of the diaphragm. The frequency characteristics become flat.

For this reason, as a diaphragm that satisfies the above-mentioned performance requirements, diaphragms formed by paper-making of beaten natural ml, chemical fibers, or fiber materials that are a mixture of these have been widely manufactured. . Since such a diaphragm is manufactured by paper-making, it is susceptible to water and moisture, and swelling and deterioration of its performance occur due to absorption of water.

However, recently, the manner in which speakers are used has expanded, such as when speakers are used outdoors and when mounted on doors or rear in automobiles, and more and more speakers are being exposed to water, humidity, and sunlight.

Therefore, the speaker diaphragm itself is required to have water repellency, water resistance, weather resistance, and the like.

Conventional methods for increasing the water resistance of diaphragms include, for example, applying a thermosetting resin to the base material after papermaking and applying heat and pressure to cover the main surface; The material is impregnated with a suitable polymer solution, dried, heated,
A method is known in which a process such as pressurization is applied to cover the entire base material from the main surface to the inside with a resin made of the polymer.

However, the former method of the above conventional method is waterproof! +! lJ!
! A diaphragm with a + rating has high waterproofness and a large Young's modulus, but it is difficult to flatten the sound pressure frequency characteristics because of its large density and small internal loss. In addition, when using the author's method, if the polymer solution is impregnated and adhered until it has sufficient waterproofness, the caries of the base material will be added to the layer and the Young's modulus will decrease, resulting in the high frequency range of the sound pressure frequency response. Efficiency has always deteriorated as the output level has decreased.

Furthermore, in any of the above methods, there is a problem in weather resistance, for example, when exposed to strong direct sunlight for a long period of time, the resin covering the diaphragm deteriorates and turns yellow.

As described above, conventional speaker diaphragms have not been able to simultaneously satisfy the physical properties of a diaphragm, such as Young's modulus, density, and internal loss, as well as waterproofness and weather resistance.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a diaphragm for a speaker that has a high Young's modulus, a low density, an appropriate internal loss, water resistance, and sufficient weather resistance.

The speaker diaphragm of the present invention comprises a base material made of paper made of natural uA miscellaneous, chemical fibers, or a mixture thereof, impregnated with an acrylic resin solution and cured, and a base material provided on the main surface of the base material. It is characterized by consisting of a coat of UV-curable acrylic resin.

IIL Hereinafter, one embodiment of the present invention will be described based on the accompanying drawings and the table below.

First, natural tlH, such as NBKP (softwood bleached kraft valve), is beaten as a raw material, and the beating degree is 20 to 22.
V to degree SR! J Adjust. Thereafter, it is dispersed in a suspension in a papermaking tank, and a desired diaphragm shape, for example, a cone-shaped papermaking screen is used to make paper.Then, the paper is made into paper using a cone-shaped mold at a temperature of about 180"C for 3 degrees. A base material is formed by drying under a pressure press of approximately OKg/Cm2.

Next, MMA resin (methyl methacrylate) as an acrylic resin is diluted with a suitable solvent such as thinner, and a resin solution is mixed as shown in Table 1 to produce UA.

Then, a cone-shaped base material is immersed in the prepared resin solution so that the solution is impregnated between the m strings of the bulb forming the base material, and the acrylic resin is attached to the uAs in the base material.

Thereafter, the solvent is volatilized and dried using hot air at a temperature of approximately 60° C. to 80° C. in terms of drying.

Furthermore, a solution of ultraviolet curable acrylic 61 resin is blended and prepared.

A solution of an ultraviolet curable acrylic resin is applied to the main surface of the dried substrate by spraying.

At this time, the desired thickness of the ultraviolet curable acrylic resin coating can be easily achieved by adjusting the viscosity and adhesion amount of the ultraviolet curable acrylic resin solution.

Thereafter, it is completely cured by irradiating ultraviolet rays of about 80 W/cm' for about 5 to 10 seconds, and a film of ultraviolet curable acrylic resin is fixedly formed on the main surface.

The base material that has gone through these steps is cut into a predetermined shape to obtain a speaker imaging plate.

FIG. 1 is a sectional view of the speaker diaphragm 1 of this example obtained in this way, and shows a cone-shaped one.

FIG. 2 is an enlarged cross-sectional view of the part indicated by circle A in FIG. A resin coating 4 is provided.

Polyurethane resins and vinyl acetate resins are generally used as sealants here, but these have extremely poor weather resistance and cause the resin parts to deteriorate, so acrylic resins, which have excellent weather resistance, are used as fillers. is being carried out.

The test results for the physical properties, waterproofness, and weatherability of the obtained diaphragm according to this example are shown.

First of all, Table 2 shows the physical property values of the diaphragm of this example and the diaphragm made only of a base material that has not yet been waterproofed.

Comparing the two, the diaphragm of this example has almost the same physical properties as the base material without an extreme increase in density, and there is no deterioration in physical properties even after treatment. I understand.

Next, an air permeability test based on JIS-P8117 was conducted on the diaphragm of the present invention and the untreated base material, and the waterproof properties of the two were compared. As a result, in the case of the untreated base material, the FR of 100 cc was 53.3 seconds, but in the case of the diaphragm of this example, the FR did not reach 100 cc even after 10 minutes. This indicates that the diaphragm of the present invention has an excellent waterproof property equivalent to that of a diaphragm base material impregnated with, for example, a polyurethane resin.

Finally, the whiteness in a weather resistance test using a Sunshine Super Long Life Weather Meter (Suga Test Instruments Co., Ltd., Model WEL-8LIN-10, black panel surface temperature 63 degrees, no water spraying) using a carbon arc as a light source. The changes over time in the degree of yellowing and the change over time in the degree of yellowing will be compared for the 1tiflI board of the present invention and the diaphragm impregnated with a polyurethane resin.

FIG. 3 is a graph showing the change in whiteness over time, where line A shows the whiteness of the diaphragm of this example, and FJB shows the whiteness of the IrXvJ board impregnated with polyurethane resin.

From FIG. 3, it can be seen that even after 500 hours, the whiteness of the diaphragm of this example decreased less than that of the polyurethane resin.

Figure 4 is a graph showing the change in yellowing degree over time, and line A
indicates the degree of yellowing of the diaphragm of this example, and line B indicates the degree of yellowing of the diaphragm impregnated with polyurethane resin. From FIG. 4, it can be seen that even after 500 hours have elapsed, the diaphragm of the actual hN example shows almost no change, and there is no yellowing as in the case of polyurethane resin (no deterioration of the resin occurs).

In the above example, natural u! Although the explanation has been given on miscellaneous materials, it is also possible to apply the present invention to base materials made from chemical fibers or composite materials thereof. In addition, the waterproof property can be further improved by adding an inner sizing material such as urea formaldehyde resin or styrene resin to the beating valve during the papermaking process.

Furthermore, the present invention is not limited to the diaphragm, but also produces effects similar to those of the above embodiments in other speaker members such as center caps and edges obtained by papermaking.

Effects of the Invention According to the present invention, by adhering an acrylic resin to a paper-made base material and then forming a thermosetting acrylic resin film, it has waterproofness and water resistance while maintaining excellent acoustic properties. A diaphragm is obtained which also has excellent weather resistance.

[Brief explanation of drawings]

FIG. 1 is a sectional view of the speaker diaphragm of the present invention, FIG. 2 is an enlarged sectional view of the portion indicated by circle A in FIG. FIG. 4 is a graph showing the change in whiteness over time of a diaphragm impregnated with a polyurethane-based resin, and FIG. It is a graph showing changes. Explanation of symbols of main parts

Claims (1)

[Claims] (1) A base material made of natural fibers, chemical fibers, or a mixture thereof, impregnated with and attached to an acrylic resin solution, and an ultraviolet-curable acrylic resin provided on the main surface of the base material. A speaker diaphragm comprising a resin film.