JP2000115885A - Member for loudspeaker and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce no poisonous gas at smoking, to make a member lightweight and high in elasticity, and to obtain both waterproofing and flame resistance at the same time by using an organic phosphor and nitrogen-containing compound and a specific water-repellent compounds in combination. SOLUTION: A water-repellent compound and organic phosphor and nitrogen- containing compound is stuck to molded natural fiber. The water-repellent compound is a compound having a water-repellent functional group, which is a saturated hydrocarbon group, an aromatic hydrocarbon group, a perfluoroalkyl group, etc. The water-repellent compound further has a hydroxyl group, an amino group, or a carboxyl group. This water-repellent compound includes a solvent base or emulsion base compound; and the solvent base compound is 2,2,2,-trifluoroethanol, etc., and the emulsion base compound is perfluoro-n-octanoic acid, etc. The organic phosphor and nitrogen-containing hydrocarbon compound is, e.g. melamine phosphate or melamine cyanurate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a speaker member used for various kinds of audio equipment and a method of manufacturing the same.
More specifically, the present invention relates to a speaker member which does not generate toxic gas when emitting smoke, is lightweight and highly elastic, and simultaneously satisfies excellent waterproofness and flame retardancy, and a method of manufacturing the same.

[0002]

2. Description of the Related Art In recent years, for components such as electric equipment,
There is a strong demand for improving heat resistance and flame retardancy. This is to prevent ignition (and fire resulting therefrom) caused by abnormal temperature rise due to failure of the electrical equipment and the like.

[0003] Ignition and fire due to the above-mentioned failures are also problems in speakers. The ignition mechanism of the speaker is, for example, as follows: the amplifier is damaged for some reason, a direct current is applied to the speaker unit, the voice coil is abnormally heated, and the lead wire is disconnected. As a result, the disconnection part sparks and ignites from the adhesive part fixing the lead wire, and spreads to the cone paper.

On the other hand, waterproofness is also a very important characteristic for a speaker, and a speaker member having excellent waterproofness is required. However, the property of suppressing ignition (that is, flame retardancy) and the waterproofness (or water repellency) are opposite properties, and it is extremely difficult to satisfy both properties at the same time.

An attempt to obtain a speaker member having excellent flame retardancy and / or waterproofness has been made in Japanese Patent Publication No. 57-50399.
And Japanese Patent Publication No. Sho 58-46920 and Japanese Patent Laid-Open Publication No. Sho 58-1396. Japanese Patent Publication No. 57-50399 describes a speaker diaphragm using a water-soluble organic phosphorus-based flame retardant and a silicone-based water repellent. Japanese Patent Publication No. 58-46920,
A loudspeaker diaphragm obtained by mixing an organic flame retardant containing nitrogen, phosphorus and a halogen compound, a fixing agent and a water repellent (sizing agent) with a pulp slurry and making a paper is described. JP-A-58-1396 describes a diaphragm for a speaker using an organic phosphorus-containing nitrogen-containing compound.

[0006]

However, these techniques have the following problems, respectively.

In the technique described in Japanese Patent Publication No. 57-50399, a water-soluble organic phosphorus-based flame retardant is used, so that a large amount of a silicone-based water repellent must be added in order to increase the waterproofness. As a result, the weight of the diaphragm increases, and
Strength decreases. The technique described in Japanese Patent Publication No. 58-46920 is poor in workability because an organic flame retardant, a fixing agent and a water repellent are mixed into a pulp slurry and the paper is made. In addition, since a halogen compound (particularly, chlorine or bromine) is used, a large amount of toxic gas is generated during combustion, which adversely affects the human body. Furthermore, this technique does not provide sufficient waterproofness. The technique described in Japanese Patent Application Laid-Open No. 58-1396 uses an organic phosphorus-containing nitrogen-containing compound alone, and therefore has extremely low waterproofness and insufficient strength.

As described above, even in the attempts described in the above publications, a speaker member satisfying both flame retardancy and waterproofness cannot be obtained. Therefore, a speaker member that satisfies both flame retardancy and waterproofness at the same time is very strongly desired.

The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to generate no toxic gas when smoking, to be lightweight and highly elastic, to have excellent waterproofness and It is an object of the present invention to provide a speaker member that simultaneously satisfies flame retardancy and a simple manufacturing method thereof.

[0010]

Means for Solving the Problems The present inventors have conducted intensive studies on the flame retardancy and waterproofness of the material used for the speaker member, and as a result, have found that the organic phosphorus-containing nitrogen-containing compound and the specific water-repellent compound are combined. It has been found that a speaker member having both excellent waterproofness and flame retardancy can be obtained by using the same, and the present invention has been completed.

The speaker member of the present invention includes a natural fiber molded into a predetermined shape; and a water-repellent compound and an organic phosphorus-containing nitrogen-containing compound attached to the natural fiber.

In a preferred embodiment, the water-repellent compound and the organic phosphorus-containing nitrogen-containing compound are chemically attached to the natural fibers.

[0013] In a preferred embodiment, the water-repellent compound has at least one functional group selected from a saturated hydrocarbon group, an aromatic hydrocarbon group, a perfluoroalkyl group and a fluorine-containing hydrocarbon group.

In a preferred embodiment, the water-repellent compound further has at least one functional group selected from a hydroxyl group, an amino group and a carboxyl group.

In a preferred embodiment, the water-repellent compound is 2,2,2-trifluoroethanol, hexafluoroisopropanol, 3-aminobenzotrifluoride, pentafluoroaniline, trifluoroacetic acid, and perfluoro-n- Selected from octanoic acid.

In a preferred embodiment, the organic phosphorus-containing nitrogen-containing compound is melamine phosphate.

The present invention also provides a method for manufacturing a speaker member. This method comprises the steps of molding natural fibers into a predetermined shape; impregnating or coating the molded natural fibers with a treatment liquid containing a water-repellent compound and an organic phosphorus-containing nitrogen-containing compound; And heat treating the natural fibers treated with the treatment liquid.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION The speaker member of the present invention includes natural fibers molded into a predetermined shape; and a water-repellent compound and an organic phosphorus-containing nitrogen-containing compound attached to the natural fibers. The natural fiber used in the present invention is not particularly limited, and any appropriate natural fiber (for example, natural cellulose fiber such as wood pulp) is used.

In the speaker member of the present invention, the water-repellent compound and the organic phosphorus-containing nitrogen-containing compound adhere to the molded natural fiber. The water-repellent compound is typically a compound having a water-repellent functional group. As the water-repellent functional group, a saturated hydrocarbon group (for example, a linear or branched alkyl group having 2 to 20 carbon atoms, preferably a linear alkyl group having 3 to 8 carbon atoms) ,
Aromatic hydrocarbon group (for example, phenyl group, benzyl group,
Naphthyl group), perfluoroalkyl group (eg, perfluoromethyl group, perfluoroethyl group, perfluoropropyl group), fluorine-containing hydrocarbon group (eg, 2,2,
2-trifluoroethyl group, hexafluoroisopropyl group, 3-aminobenzotrifluoro group, perfluoro-n-
Octyl group) and the like. Particularly preferred water repellent functional groups are fluorine-containing hydrocarbon groups. Preferably, the water-repellent compound further has a hydroxyl group, an amino group or a carboxyl group. Such a water-repellent compound includes a solvent system or an emulsion system, and specific examples thereof include 2,2,
Examples include 2-trifluoroethanol, hexafluoroisopropanol, 3-aminobenzotrifluoride, pentafluoroaniline, trifluoroacetic acid, and perfluoro-n-octanoic acid. Particularly preferred compounds are 2,2,2-trifluoroethanol as the solvent system and perfluoro-n-octanoic acid as the emulsion system.

Examples of the organic phosphorus-containing nitrogen-containing compound include melamine phosphate and melamine cyanurate. In the present invention, melamine phosphate is typically used. Melamine phosphate is prepared in any suitable way. FIG. 1 is a reaction scheme showing an example of a method for preparing melamine phosphate. As shown in FIG. 1, melamine phosphate can be prepared by reacting melamine with formaldehyde to prepare trimethylol melamine, and reacting it with phosphoric acid in water or a water-soluble alcohol.

Preferably, the water repellent compound and the organic phosphorus-containing nitrogen-containing compound are chemically attached to natural fibers. For example, a case where the natural fiber is a cellulose fiber, the water-repellent compound is perfluoro-n-octanoic acid, and the organic phosphorus-containing nitrogen-containing compound is melamine phosphate will be described with reference to FIG. As is apparent from FIG. 2, the melamine phosphate is converted into a cellulose fiber by ionic bonding between a hydroxyl group (anion portion) of the cellulose fiber and an ammonium group (cation portion) formed by dissociation of a phosphate ion from the melamine phosphate. Adheres to Furthermore, the cellulose fibers are bonded to each other via melamine phosphate and perfluoro-n-octanoic acid by ionic bonding between the ammonium group of melamine phosphate and the perfluoro-n-octanoic acid ion.

Next, an example of a method for manufacturing the speaker member of the present invention will be described.

First, the natural fiber is molded into any appropriate shape by any appropriate method depending on the application. For example, when the present invention is applied to an acoustic radiation plate (diaphragm), natural fibers are beaten, and then paper is formed into a predetermined shape (for example, a cone type or a dome type) using a net. Further, for example, when the present invention is applied to a dust cap, a similar molding procedure can be adopted.

Next, the molded natural fibers are impregnated or coated with a treatment liquid containing a water-repellent compound and an organic phosphorus-containing nitrogen-containing compound. The mixing ratio of the water-repellent compound and the organic phosphorus-containing nitrogen-containing compound in the treatment liquid is preferably 5:95
The weight ratio is about 10:90. When the proportion of the water-repellent compound is less than 5% by weight, desired waterproofness cannot be obtained in many cases. If it exceeds 10% by weight, the adhesion to other speaker members (for example, in the case of a cone, the adhesion to the edge, voice coil and dust cap) and the flame retardancy may be insufficient. Many. The total concentration of the water repellent compound and the organic phosphorus-containing nitrogen-containing compound in the treatment liquid is preferably 10% by weight to 30% by weight. The adhesion amount of the water-repellent compound and the organic phosphorus-containing nitrogen-containing compound to the natural fibers is 10 to 20% by weight, preferably 10 to 13% by weight based on the weight of the natural fibers. If the amount is less than 10% by weight, the self-extinguishing property (flame retardancy) is often insufficient. If the content exceeds 20% by weight, the weight of the obtained speaker member often becomes too heavy. Examples of the solvent used for the treatment liquid include water, monohydric alcohol (eg, methanol and ethanol), and polyhydric alcohol (eg, ethylene glycol and propylene glycol). Impregnation or coating is performed by any suitable procedure.

Finally, the natural fiber molded and treated with the treatment liquid is subjected to a heat treatment to obtain a speaker member. The heat treatment is performed using any appropriate means (for example, a hot air dryer). Heat treatment temperature is typically 140 ° C to 160 ° C
It is. The heat treatment time is typically 1 to 3 minutes.

Hereinafter, the operation of the present invention will be described.

Conventionally, an organic phosphorus-containing nitrogen-containing compound (eg, melamine phosphate) as a flame retardant dissociates into a melamine ion (cation) and a phosphate ion (anion) in an aqueous solvent. Melamine ions (cations) because they attract each other electrically
Did not work effectively. More specifically, melamine ions cannot effectively ion-bond with the hydroxyl groups of natural fibers (eg, cellulose fibers), and thus cannot impart sufficient flame retardancy to cellulose fibers. It is difficult to obtain a speaker member having flame retardancy. According to the present invention, an organic phosphorus-containing nitrogen-containing compound and a specific water-repellent compound (a water-repellent compound having a small aggregation energy; for example, perfluoro-n-octanoic acid, 2,2,2-
By using trifluoroethanol in combination, the dissociated ions of the organic phosphorus-containing nitrogen-containing compound are prevented from being electrically attracted to each other. As a result, since the cation of the organic phosphorus-containing nitrogen-containing compound and the hydroxyl group of the cellulose fiber form an effective and sufficient ionic bond, the flame retardancy can be sufficiently imparted to the cellulose fiber (that is, the speaker member). . In addition, the water-repellent compound used in the present invention becomes an anion in a solvent and forms an ionic bond with the cation portion of the organic phosphorus-containing nitrogen-containing compound. As a result, this water-repellent compound not only strongly adheres to the cellulose fiber via the organic phosphorus-containing nitrogen-containing compound, but also
It also functions as a cross-linking agent for binding cellulose fibers. Therefore, not only is water repellency (waterproof) provided to the speaker member, but also strength (for example, elasticity) is increased. Further, since the speaker member of the present invention has excellent flame retardancy as described above and does not ignite even when heated, even if the conventional speaker member has caused a fire, it has a level of smoke. No problem. Moreover, the present invention does not use halogen (chlorine or bromine) as a flame retardant, and fluorine in the water-repellent compound is less toxic than chlorine or bromine.
As a result, the speaker member of the present invention does not generate toxic gas even when heated abnormally.

As described above, according to the present invention, by using an organic phosphorus-containing nitrogen-containing compound in combination with a specific water-repellent compound, no toxic gas is generated at the time of smoking, light weight and high elasticity, A speaker member that satisfies both excellent waterproofness and flame retardancy can be obtained.

Further, since the speaker member of the present invention is obtained by impregnating or coating molded natural fibers with a treatment liquid containing the above-mentioned organic phosphorus-containing nitrogen-containing compound and the above-mentioned water-repellent compound, followed by heat treatment, The process is very simple and low cost.

The present invention can be suitably applied to loudspeaker members (for example, a sound radiating plate (diaphragm), a dust cap, an edge, and an arrowhead) of various audio devices.

[0031]

Example 1 (Example 1) A bleached or unbleached North American softwood kraft pulp was beaten to 420 ml CSF with a beater, and the pulp was made in a cone shape using a net having a predetermined shape.
And dried. On the other hand, melamine phosphate dissolved in methanol and 2,2,2-trifluoroethanol dissolved in ethanol are blended at a ratio of 10: 1 (weight ratio of compound), and diluted with methanol until the total concentration becomes 20% by weight. Thus, a treatment liquid was prepared. The corn paper was impregnated with this treatment liquid.

The corn paper impregnated with the treatment liquid is heated at 150 ° C. for 2 hours.
After heat treatment for minutes, a sound emitting plate for a speaker (paper cone having a diameter of 16 cm) was obtained.

The following evaluation was performed on the obtained acoustic radiation plate. The evaluation results are shown in Table 1 below.

1 Evaluation of Elasticity In order to evaluate the elastic modulus of the acoustic radiation plate, 200 g / m 2 of cellulose fiber (kraft pulp) was measured in accordance with JIS P8209.
Was prepared, and was impregnated and heat-treated under the above-mentioned processing solution and the above-mentioned processing conditions, and the Young's modulus of the obtained sheet was measured by using a vibration lead method.

2 Evaluation of Flame Retardancy The US Automotive Safety Standards (FMVSS) method (basically JIS D1201)
According to the following).

3 Evaluation of Waterproofness A speaker unit was manufactured using the obtained sound radiating plate, and input was performed at a rated input of 15 W using White Noise with JIS Filter. Shower from the back of the unit (flow rate 6 l / min)
For 120 minutes and then allowed to stand still for 24 hours.
Immediately after the shower was started, water leakage and seepage to the speaker surface, deformation and discoloration of the speaker were examined, and further, f0 change rate after 24 hours was examined. OK when no change is observed and f0 change rate is less than 30%, N when change is observed or f0 change rate exceeds 30%
G.

4 Frequency Characteristics The frequency characteristics before and after the waterproof test at 50 cm on axis and 1 W of input were examined for Example 1, Comparative Examples 1 and 2. The results are shown in FIG.

[0038]

[Table 1] (Example 2) Melamine phosphate dissolved in water and perfluoro-n-octanoic acid dissolved in propylene glycol were blended at a ratio of 20: 1 (weight ratio of compound), and water was mixed until the total concentration became 30% by weight. To prepare a treatment solution. The treatment liquid was coated on the back surface of the cone paper obtained in the same manner as in Example 1 by spin coating. The following procedure was performed in the same manner as in Example 1 to obtain an acoustic radiation plate for a speaker, and was subjected to the same evaluation as in Example 1. The results are shown in Table 1 above. Comparative Example 1 A sound radiating plate for a speaker was prepared in the same manner as in Example 1 except that a treatment liquid was prepared using a water-soluble flame retardant and a silicone-based water repellent described in JP-B-57-50399. It was prepared and subjected to the same evaluation as in Example 1. The results are shown in Table 1 and FIG. (Comparative Example 2) A sound radiating plate for a speaker was prepared in the same manner as in Example 1 except that a treatment solution was prepared using only the organic phosphorus-containing nitrogen-containing compound described in JP-A-58-1396.
The same evaluation as in Example 1 was performed. The results are shown in Table 1 and FIG. (Comparative Example 3) An acoustic radiation plate for a speaker obtained by impregnating a nitrified cotton (thin diluted with ethyl acetate to a concentration of 7%) with a fluororesin treatment liquid (3% by weight based on the nitrified cotton) without performing a flame retardant treatment. Was prepared and subjected to the same evaluation as in Example 1. The results are shown in Table 1 above.

As is clear from Table 1, the speaker member of the present invention satisfies both excellent flame retardancy and waterproofness at the same time. Furthermore, as is clear from Table 1, the speaker member of the present invention is lightweight and highly elastic. In addition, the speaker member of the present invention has an advantage that the fluorine-containing compound generates less toxic gas than other halogen compounds, so that the toxic gas is not generated so much as to adversely affect the human body when smoking. Further, as is apparent from a comparison between FIG. 3 and FIG. 5, the distortion of the speaker member of the present invention in the middle and low frequency ranges after the waterproof test is smaller than that of the comparative example.

[0040]

According to the present invention, by using a combination of an organic phosphorus-containing nitrogen-containing compound and a specific water-repellent compound, no toxic gas is generated at the time of smoking, light weight and high elasticity, and excellent waterproofness is obtained. The speaker member which satisfies the property and the flame retardancy at the same time and the simple manufacturing method thereof can be obtained.

[Brief description of the drawings]

FIG. 1 is a reaction scheme showing an example of a method for preparing melamine phosphate.

FIG. 2 is a conceptual diagram for explaining a bonding state between a water-repellent compound, an organic phosphorus-containing nitrogen-containing compound, and a cellulose fiber.

FIG. 3 is a graph showing frequency characteristics of the speaker member of Example 1 before and after a waterproof test.

FIG. 4 is a graph showing frequency characteristics of a speaker diaphragm of Comparative Example 1 before and after a waterproof test.

FIG. 5 is a graph showing frequency characteristics of a speaker diaphragm of Comparative Example 2 before and after a waterproof test.

Claims (7)

[Claims] 1. A speaker member comprising: a natural fiber molded into a predetermined shape; and a water-repellent compound and an organic phosphorus-containing nitrogen-containing compound attached to the natural fiber. 2. The speaker member according to claim 1, wherein the water-repellent compound and the organic phosphorus-containing nitrogen-containing compound are chemically attached to the natural fibers. 3. The water-repellent compound is a saturated hydrocarbon group,
The speaker member according to claim 1 or 2, wherein the member has at least one functional group selected from an aromatic hydrocarbon group, a perfluoroalkyl group, and a fluorine-containing hydrocarbon group. 4. The speaker member according to claim 1, wherein the water-repellent compound further has at least one type of functional group selected from a hydroxyl group, an amino group, and a carboxyl group. 5. The method according to claim 1, wherein the water-repellent compound is 2,2,2-trifluoroethanol, hexafluoroisopropanol, 3-aminobenzotrifluoride, pentafluoroaniline,
The speaker member according to claim 4, wherein the member is selected from trifluoroacetic acid and perfluoro-n-octanoic acid. 6. The speaker member according to claim 1, wherein the organic phosphorus-containing nitrogen-containing compound is melamine phosphate. 7. A step of molding the natural fiber into a predetermined shape; a step of impregnating or coating the molded natural fiber with a treatment liquid containing a water-repellent compound and an organic phosphorus-containing nitrogen-containing compound; And subjecting the natural fibers treated with the treatment liquid to a heat treatment.