JPS6135095A - Diaphragm for speaker - Google Patents

Abstract

PURPOSE:To obtain the hardness and water proof the same or more as a thermosetting resin by making natural and chemical fibers or their mixture, impregnating a polyurethane resin solution and providing a ultraviolet cured resin coating on the main surface of a dried and cured base material. CONSTITUTION:A fiber 1 is filled by a polyurethane resin 2, and a coating 3 made of a ultraviolet cured resin is formed on the main surface of a base material 4. The more thickly and uniformly the coaring 3 is formed on the main surface, water proofing effects for the interior of the base material 4 is increased. Consequently, the bondage as strong as possible between the fibers 1 and the filling by the polyurethane resin can improve the water proofing effect. The fiber 1 means a natural or chemical fiber, and the base 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, which widens the frequency band of the speaker.The larger the internal loss, the less the split resonance of the diaphragm. Frequency characteristics become flat.

For this reason, vibration plates that satisfy the above-mentioned performance requirements are conventionally used to produce vibrations produced by fabricating fiber materials such as beaten natural fibers, synthetic fibers, or a mixture of these materials. Boards are 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 or mounted on doors in automatic systems, 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 have water repellency and water resistance.

Conventional methods for increasing the water resistance of diaphragms include, for example, attaching thermosetting resin to the base material after papermaking and applying heat and pressure treatment to cover the main surface, and applying fibrous thermoplastic resin to the base material. A method is known in which, after paper-making, a fiber material made of natural fibers, chemical fibers, or a composite of these fibers is combined and subjected to heat-pressure treatment to heat-fuse the resin and cover the main surface.

However, in the former method of the conventional method, the diaphragm is waterproof and has a large Young's modulus, but it is difficult to flatten the sound pressure frequency characteristics due to its large density and small internal loss. . If you use the latter method, heat the water until it has sufficient waterproof properties. When a synthetic resin is added, the 17 ring rate decreases, and the output level in the sound range of the sound pressure frequency characteristic decreases, and the efficiency also deteriorates.

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.

l''Δ(1) 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, and sufficient water resistance while maintaining sufficient inner lit loss.

The speaker diaphragm of the present invention is made of natural lllff, chemical!
I [or a PL made of a paper made from a mixture of these and impregnated with a polyurethane resin solution and dried and cured, and a coating of an ultraviolet curable resin installed on the main surface of the profiteering material] There is.

Embodiment Hereinafter, one embodiment of the present invention will be explained based on the corrected drawings and the table below.

First, as a raw material, natural lj miscellaneous, such as NBKP (conifer exposed to Kula 71), is beaten to a degree of beating of 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 screen is used to make paper, followed by a cone-shaped mold at a temperature of about 180°C for 3°0Kq. A base material is formed by drying under a pressure press of about /C112.

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

The prepolymer isocyanate produced by the reaction of functional polyol and diisocyanate is diluted with a solvent such as Simbu.
This solution is used.

Then, a cone-shaped base material is immersed in the prepared solution, and the solution is impregnated between the holes of the bulb forming the base material, so that the fibers in the base material are coated with the polyurethane resin.

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

Further, solutions of ultraviolet curable resins (1), (2) and (3) are mixed and prepared as shown in Table 2. Hereinafter, these three kinds of ultraviolet curable resins are applied to the base H separately to manufacture three corresponding diaphragms (1), (2), and (3).

Table 2 Then, a solution of an ultraviolet curable resin is applied to the J-1 side of the dried base material by spraying, dipping, or the like. At this time, the desired thickness of the ultraviolet curable resin coating can be easily achieved by adjusting the viscosity and adhesion amount of the 'tit solution.

After that, take a setting time of 1 to 3 minutes, and then
(7) The ultraviolet curable resin is cured by irradiating it with ultraviolet light at 80 W/Cm' for 2 to 4 seconds from a distance of about cm.

1-I went through the process described! Three types of speaker diaphragms (1), (2), and (3) are obtained by cutting 1ttA into predetermined shapes.

These porous fillers are necessary to make Group I waterproof by making natural fiber hats, but the pre-bolimer isocyanate in polyurethane resins self-polymerizes due to heat, moisture, etc. to form three-dimensional polymers. Therefore, even under the conditions as in this example, the sealing effect is sufficiently exhibited. However, when the bond between fibers is weak, for example when the diaphragm base material is dried without being pressurized with a mold, etc., polyA4 polymers such as glycol and 1-liol are bonded to the prepolymer isocyanate. By adding a compound or a polyamino compound such as diamine or triamine as a curing agent, higher sealing effect and water resistance can be imparted to IJI4.

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

FIG. 2 is an enlarged sectional view of the portion indicated by circle A in FIG. 1, which forms the base material 4! I miscellaneous 1 is sealed with polyurethane resin 2. Further, a coating 3 made of an ultraviolet curable resin is formed on one of the base materials 4. Here, the more uniformly and thickly the ultraviolet curable resin coating 3 is formed on the main surface, the greater the waterproofing effect on the inside of the U material 4 becomes. Therefore, bonding between the fibers 1 as strong as possible and sealing with polyurethane resin will further enhance the effect. Further, the fiber If11 is a natural fiber or a chemical fiber, and the base material 4 is formed by paper-making one or a mixture of these fibers.

Table 3 shows three types of diaphragms (1), (2), and (3) of this example corresponding to each ultraviolet curable resin, and the base material that has not yet been waterproofed. The physical property values are shown.

/' Comparing the two, the diaphragm of this example has an extremely increased density, and both Young's modulus and internal loss have increased, indicating that the characteristics of the base material are taken advantage of. Recognize.

In addition, we conducted an air permeability test based on JIS-P8117 on the present invention and found that 100CC was applied.
While the untreated 11jl material took 53.3 seconds, all of the diaphragms of this example did not reach 100cc even after 10 minutes, indicating that sufficient sealing had been achieved.

Furthermore, Fig. 3 shows the output sound pressure frequency characteristic curve A of the speaker using the diaphragm (2) of this example measured under the same conditions, and the output sound pressure of the speaker using the diaphragm made of a base material that is not waterproofed. It is a graph showing the frequency characteristic curve B and 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.

Although natural fibers have been described in this embodiment, chemical fibers or composite materials thereof may also be used. Furthermore, the waterproof property can be further improved by adding an inner sizing material such as urea formaldehyde resin or styrene resin to the beaten pulp during the papermaking process.

1 rim According to the present invention, polyurethane resin at a relatively low temperature,
Because it hardens, even materials that are outside the range of heat treatment using I3C (for example, unfaded materials containing synthetic fibers) have hardness equivalent to or higher than thermosetting resins, and are waterproof and water resistant. A diaphragm covering the right side is obtained.

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. .

Since the base material is sufficiently sealed, the ultraviolet curable resin solution will not get onto the base material, so depending on the purpose of the diaphragm, the thickness and hardness of the waterproof coating can be applied or soaked. It can be easily adjusted by i1 etc.

[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 graph which shows the output sound pressure frequency characteristic of. Explanation of symbols of main parts

Claims (1)

[Claims] Consists of a base material made of natural fibers, chemical fibers, or a mixture thereof, impregnated with a polyurethane resin solution and dried and cured, and a coating of an ultraviolet curable resin provided on the main surface of the base material. A speaker diaphragm characterized by: