JPS6135100A - Diaphragm for speaker - Google Patents

Abstract

PURPOSE:To obtain the hardness and water proof more than a thermosetting resin has by making natural and chemical fibers or their mixture, impregnating a polyurethane resin solution and constituting a diaphragm from a dried and cured basic material. CONSTITUTION:Since a fiber 1 is filled by a polyurethane resin 2, the strong bondage between the fibers 1 improves the water proof due to the resin 2. Provided that the fiber 1 means a natural or chemical fiber, and a basic material 4 is formed by making the natural or chemical fiber alone or their mixture.

Description

[Detailed description of the invention] Technical field The present invention relates to a diaphragm for a speaker.

Background Art In general, the performance required of a speaker diaphragm is to be lightweight, have a high Young's modulus, a low density, and have an appropriate internal loss so as to obtain good output sound pressure frequency characteristics of the speaker. That is what we are 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.The larger the internal loss, the lower the split resonance of the diaphragm. The frequency characteristics become flat.

For this reason, diaphragms that satisfy the above-mentioned performance requirements have traditionally been made using beaten natural fibers, chemical I.
A wide range of imaging plates are manufactured by forming a fiber material from a fiber material containing a variety of materials or a mixture thereof. Since such a diaphragm is manufactured by paper-making, it is susceptible to water and moisture, and moisture absorption causes dampness and deterioration of its performance.

However, in recent years, speakers have been used outdoors and in cars.
The ways in which speakers are used are expanding, such as in the case of door mounts, and the number of speakers that come into contact with water and moisture is increasing. Therefore, the diaphragm itself of the speaker is required to be water repellent and water resistant.

Conventional methods for increasing the water resistance of diaphragms include, for example, applying thermosetting resin to the base material after papermaking and applying heat and pressure to cover the main surface. After mixing and forming a thermoplastic resin with natural fibers, chemical fibers, or a composite fiber material of these, the resin is heated and pressurized. Q''; t2y u-, the method of covering the main surface is 9JJ.

However, although the diaphragm subjected to the former waterproofing treatment of the conventional method has high waterproofness and a large V-zig ratio, it has a high density and low internal loss, so the sound pressure frequency characteristics are flattened. In addition, when using the latter method, if thermoplastic resin fibers are added until sufficient waterproofness is achieved, the V-zig ratio will decrease, and the output level in the high frequency range of the sound pressure frequency characteristic will decrease. As efficiency decreases, so does efficiency.
It used to be that

As described above, conventional speaker diaphragms have not been able to simultaneously satisfy sufficient waterproof properties and desirable physical properties such as Young's modulus, density, and internal loss.

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

The speaker diaphragm of the present invention is made of natural fiber, chemical fiber, or a mixture thereof, and is made of polyurethane-based P.
It is characterized by consisting of a group O Δ which is impregnated with an f4 fat solution and dried and hardened.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to the accompanying drawings and the table below.

First, as a raw material, natural fiber such as NBKP (softwood bleached pulp to pulp) is subjected to beating 5, and the beating degree is 20 to 2.
Adjust to SR twice. Thereafter, it is dispersed in a suspension in a papermaking tank, and a desired diaphragm shape, for example, a cone-shaped papermaking net, is made into paper.Then, the U3° is placed in a cone-shaped mold at a humidity of about 180'C. A base material is formed by drying under a pressure press of approximately OKg/Cm'.

Next, a polyurethane resin solution is mixed and prepared as shown in Table 1.

Table 1 Here, as the polyurethane resin, C is used, for example, a solution prepared by diluting a prepolymer isocyanate produced by the reaction of a trifunctional polyol and diisocybute with a solvent such as thinner.

Then, a cone-shaped base material is immersed in the prepared solution to impregnate the fibers of the bulb forming the base material with the solution, thereby adhering the polyurethane resin to the fibers in the base material.

Thereafter, the solvent is evaporated and dried using hot air at a temperature of about 60'C in a dryer.

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

In addition, these porous fillers are necessary to make natural paper NW paper-made and waterproof, but the prepolymer isocyna-1 applied to the polyurethane resin is heat-resistant. Since the three-dimensional polymer is formed by self-handling in the presence of moisture, etc., the sealing effect is sufficiently exhibited even under the conditions of this example. However, for example, when the bond between fibers is weak when the diaphragm base material is dried without being pressurized with a mold or the like, polyoxy compounds such as glycols and triols, diamines, - By adding a polyamino compound exclusively for Riamine as a curing agent, higher sealing effect and water resistance can be imparted to the base material.

FIG. 1 is a cross-sectional view of the speaker diaphragm of this embodiment, which is thus iqed, and shows a cone-shaped speaker diaphragm.

FIG. 2 is an enlarged cross-sectional view of a portion indicated by a circle △ in FIG. To that end, we need a strong IH
The bond between lfi 1 is enhanced by the polyurethane resin 2. Further, the fibers 1 are made of artificial t+lt or chemical radiation waste, and the base material 4 is formed by paper-making 111 or a mixture of these fibers.

Table 2 shows the diaphragm C of this example, one that was heated and dried at 60°C (1), one that was heated and dried at 60°C with a hardening agent added (2), and one that was still waterproof. The physical property values of each untreated base material are shown.

Comparing the two, the diaphragm of this example eliminates the extreme increase in density, and also reduces Young's modulus, internal loss, and -b by jη
It can be seen that the characteristics of WIJ are being utilized.

Furthermore, as a result of conducting an air permeability test based on JIS-1]8117 on the diaphragm of the present invention, it was found that the 100 cC application time was 53.3 seconds for the untreated base material, whereas the diaphragm of the present example It did not reach 100cc even after 10 minutes, indicating that sufficient sealing had been done.

Roughly speaking, Figure 3 shows the output sound pressure frequency characteristic curve A of the speaker using the diaphragm of this example measured under the same conditions, and the output sound pressure frequency characteristic curve A of the speaker using the diaphragm made of a base material that is not waterproofed. 1t side! dB and is a graph comparing the two. The speaker using the diaphragm of this example is more
It can be seen that there is little split resonance and a flat output sound pressure frequency characteristic is obtained in the treble range.

In this example, natural tjAH was explained, but chemical fibers or composite materials thereof can also be applied. Also,
Waterproofing properties can be further improved by adding internal size particles such as urea formaldehyde resin or styrene resin to the beaten pulp during papermaking.

According to the present invention, since the polyurethane resin is cured at a relatively low temperature, even materials that are difficult to heat-treat at high temperatures (fibrous material V [which forms the base material, for example, containing synthetic fibers]) can be thermally cured. A diaphragm can be obtained which has hardness equal to or higher than that of the plastic resin, and which is waterproof and water resistant.

Since the sealing effect is fully demonstrated even without heat pressing, there are no negative effects from an acoustic perspective such as increased density of the base material or reduction in internal loss due to heat pressing, and the physical properties of the base material can be fully utilized. .

The main surface of the base material is sufficiently sealed with the cured polyurethane resin and does not require the conventional waterproofing treatment with a coating, so the number of manufacturing steps can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a speaker diaphragm according to the present invention, FIG. 2 is an enlarged sectional view of the portion indicated by circle A in FIG. It is a J graph showing output sound pressure frequency characteristics of a speaker. Explanation of symbols of main parts

Claims (1)

[Claims] A diaphragm for a speaker comprising a base material made of natural fiber, chemical fiber, or a mixture thereof, impregnated with a polyurethane resin solution, and dried and hardened.