JP3911874B2 - Speaker member and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a speaker member used for various acoustic devices and a method for manufacturing the same. More specifically, the present invention relates to a speaker member that does not generate a toxic gas when smoked, is lightweight and highly elastic, and satisfies excellent waterproofness and flame retardancy at the same time, and a method for manufacturing the same.
[0002]
[Prior art]
In recent years, there has been a strong demand for improving heat resistance and flame retardancy of component parts such as electrical equipment. This is to prevent ignition (and fire) due to abnormal temperature rise due to failure of electrical equipment.
[0003]
Firing and fire due to the above failures are also a problem 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 portion is disconnected. As a result, the disconnected portion sparks, ignites from the bonded portion that fixes the lead wire, and spreads on the cone paper.
[0004]
On the other hand, with respect to speakers, waterproofness is also a very important characteristic, and a speaker member having excellent waterproofness is required. However, the property of suppressing ignition (that is, flame retardancy) and the waterproof property (or water repellency) are contradictory properties, and it is very difficult to satisfy both properties at the same time.
[0005]
Attempts to obtain a speaker member having excellent flame retardancy and / or waterproofness are described in JP-B-57-50399, JP-B-58-46920 and JP-A-58-1396. Yes. Japanese Patent Publication No. 57-50399 describes a speaker diaphragm using a water-soluble organic phosphorus flame retardant and a silicone water repellent. Japanese Examined Patent Publication No. 58-46920 discloses a speaker diaphragm in which an organic flame retardant containing nitrogen, phosphorus, and a halogen compound, a fixing agent, and a water repellent (sizing agent) are mixed with a pulp slurry and made into paper. Describe. Japanese Patent Application Laid-Open No. 58-1396 describes a speaker diaphragm using an organic phosphorus-containing nitrogen-containing compound.
[0006]
[Problems to be solved by the invention]
However, each of these techniques has the following problems.
[0007]
Since the technique described in Japanese Patent Publication No. 57-50399 uses a water-soluble organic phosphorus flame retardant, a large amount of a silicone water repellent must be added in order to improve waterproofness. As a result, the weight of the diaphragm increases and the strength decreases. The technique described in Japanese Patent Publication No. 58-46920 is inferior in workability because an organic flame retardant, a fixing agent and a water repellent are mixed into a pulp slurry and made into paper. In addition, since halogen compounds (especially chlorine and bromine) are used, a large amount of toxic gas is generated during combustion, which adversely affects the human body. Furthermore, sufficient waterproofness cannot be obtained with this technology. The technique described in Japanese Patent Application Laid-Open No. 58-1396 uses an organic phosphorus-containing nitrogen-containing compound alone, so that the waterproof property is extremely low and the strength is insufficient.
[0008]
Thus, even in the attempts described in the above publications, a speaker member that satisfies both flame retardancy and waterproofness cannot be obtained. Therefore, there is a strong demand for a speaker member that satisfies both flame retardancy and waterproofness at the same time.
[0009]
The present invention has been made in order to solve the above-described conventional problems. The object of the present invention is to generate no toxic gas at the time of smoke generation, to be lightweight and highly elastic, and to have excellent waterproofness and flame retardancy. It is an object of the present invention to provide a speaker member that satisfies the above requirements and a simple manufacturing method thereof.
[0010]
[Means for Solving the Problems]
As a result of intensive studies on the flame retardancy and waterproofness of materials used for speaker members, the present inventors have achieved excellent waterproofness by using a combination of an organic phosphorus-containing nitrogen-containing compound and a specific water-repellent compound. And found that a speaker member having both flame retardancy and flame retardancy can be obtained, and the present invention has been completed.
[0011]
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.
[0012]
In a preferred embodiment, the water-repellent compound and the organic phosphorus-containing nitrogen-containing compound are chemically attached to the natural fiber.
[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.
[0014]
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.
[0015]
In a preferred embodiment, the water repellent compound is from 2,2,2-trifluoroethanol, hexafluoroisopropanol, 3-aminobenzotrifluoride, pentafluoroaniline, trifluoroacetic acid, and perfluoro-n-octanoic acid. Selected.
[0016]
In a preferred embodiment, the organic phosphorus-containing nitrogen-containing compound is melamine phosphate.
[0017]
The present invention also provides a method for manufacturing a speaker member. The 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 the process of heat-processing the natural fiber processed with the processing liquid is included.
[0018]
DETAILED DESCRIPTION OF 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.
[0019]
In the speaker member of the present invention, the water-repellent compound and the organic phosphorus-containing nitrogen-containing compound are attached 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 groups (for example, phenyl group, benzyl group, naphthyl group), perfluoroalkyl groups (for example, perfluoromethyl group, perfluoroethyl group, perfluoropropyl group), fluorine-containing hydrocarbon groups (for example, 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 water repellent compounds include solvent systems or emulsion systems, and specific examples thereof include 2,2,2-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.
[0020]
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 by any suitable method. 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 trimethylolmelamine and reacting with phosphoric acid in water or water-soluble alcohol.
[0021]
Preferably, the water repellent compound and the organic phosphorus-containing nitrogen-containing compound are chemically attached to the natural fiber. For example, the case where the natural fiber is 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 apparent from FIG. 2, the hydroxyl group (anion portion) of the cellulose fiber and the ammonium group (cation portion) formed by dissociating phosphate ions from the melamine phosphate are ionically bonded, so that the melamine phosphate becomes the cellulose fiber. Adhere to. Further, the ammonium groups of melamine phosphate and perfluoro-n-octanoic acid ions are ionically bonded, whereby cellulose fibers are bonded to each other via melamine phosphate and perfluoro-n-octanoic acid.
[0022]
Next, an example of the manufacturing method of the speaker member of the present invention will be described.
[0023]
First, natural fibers are molded into any suitable shape by any suitable method depending on the application. For example, when the present invention is applied to an acoustic radiation plate (vibration plate), natural fibers are beaten, and then paper is made into a predetermined shape (for example, cone type or dome type) using a paper making net. For example, when applying this invention to a dust cap, the same shaping | molding procedure may be employ | adopted.
[0024]
Next, the molded natural fiber is 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 a weight ratio of 5:95 to 10:90. When the ratio of the water repellent compound is less than 5% by weight, the desired waterproof property is often not obtained. If it exceeds 10% by weight, adhesion to other speaker components (for example, in the case of cones, adhesion to edges, voice coils and dust caps) and 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 fiber is 10 to 20% by weight, preferably 10 to 13% by weight, based on the weight of the natural fiber. If the adhesion amount is less than 10% by weight, the self-extinguishing property (flame retardant) is often insufficient. If it exceeds 20% by weight, the obtained speaker member is often too heavy. Examples of the solvent used in the treatment liquid include water, monohydric alcohols (for example, methanol, ethanol), polyhydric alcohols (for example, ethylene glycol, propylene glycol), and the like. Impregnation or coating is performed by any suitable procedure.
[0025]
Finally, the natural fiber molded and treated with the treatment liquid is heat-treated to obtain a speaker member. The heat treatment is performed using any appropriate means (for example, a hot air dryer). The heat treatment temperature is typically 140 ° C to 160 ° C. The heat treatment time is typically 1 to 3 minutes.
[0026]
The operation of the present invention will be described below.
[0027]
Conventionally, organic phosphorus-containing nitrogen-containing compounds that are flame retardants (for example, melamine phosphate) dissociate into melamine ions (cations) and phosphate ions (anions) in an aqueous solvent. Melamine ions (cations) did not function effectively because they attracted each other. More specifically, melamine ions cannot effectively ion-bond with the hydroxyl groups of natural fibers (for example, cellulose fibers), and therefore cannot sufficiently impart flame retardancy to cellulose fibers, resulting in excellent results. It was difficult to obtain a speaker member having flame resistance. According to the present invention, an organic phosphorus-containing nitrogen-containing compound and a specific water-repellent compound (compound having a low cohesive energy; for example, perfluoro-n-octanoic acid, 2,2,2-trifluoroethanol) are used in combination. Thus, the dissociated ions of the organic phosphorus-containing nitrogen-containing compound are restrained from being electrically attracted to each other. As a result, 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, so that sufficient flame retardancy can be imparted to the cellulose fiber (that is, the speaker member). . Moreover, as shown in FIG. 2, when the organic phosphorus-containing nitrogen-containing compound is melamine phosphate, the organic phosphorus-containing nitrogen-containing compound also functions as a crosslinking agent that binds cellulose fibers together. Further, 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 . What follow, not only to impart water repellency (water resistance) to the loudspeaker member, strength (e.g., elastic modulus) is also increasing. Furthermore, since the speaker member of the present invention has excellent flame retardancy as described above, it does not ignite even if heated, so even if it is a fire in the conventional speaker member, the degree of smoke generation That's okay. Moreover, the present invention does not use halogen (chlorine, 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.
[0028]
As described above, 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 smoke generation, light weight and high elasticity, and excellent waterproofing. Thus, a speaker member that simultaneously satisfies the properties and flame retardancy can be obtained.
[0029]
Furthermore, the speaker member of the present invention is obtained by impregnating or coating a molded natural fiber with a treatment liquid containing the organic phosphorus-containing nitrogen-containing compound and the water-repellent compound, and heat-treating, so that the production process is extremely high. It is simple and low cost.
[0030]
The present invention can be suitably applied to speaker members (for example, acoustic radiation plates (vibrating plates), dust caps, edges, arrow papers) of various acoustic devices.
[0031]
【Example】
Example 1
North American coniferous bleached or unbleached kraft pulp was beaten to 420 ml CSF with a beater, made into a cone shape using a papermaking 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 (compound weight ratio) and diluted with methanol until the total concentration is 20% by weight. Thus, a treatment liquid was prepared. The cone paper was impregnated with this treatment liquid.
[0032]
The cone paper impregnated with the treatment liquid was heat-treated at 150 ° C. for 2 minutes to obtain an acoustic radiation plate for speakers (paper cone with a diameter of 16 cm).
[0033]
The following evaluation was performed about the obtained acoustic radiation board. The evaluation results are shown in Table 1 below.
[0034]
1 Elasticity Evaluation In order to evaluate the elastic modulus of the acoustic radiation plate, a flat sheet of 200 g / m2 is prepared from cellulose fiber (craft pulp) according to JIS P8209, impregnated and heat-treated with the above treatment liquid and the above treatment conditions, The Young's modulus of the obtained sheet was measured using a vibration lead method.
[0035]
2 Flame Retardancy Evaluation Evaluated according to the American Automobile Safety Standard (FMVSS) method (basically according to JIS D1201).
[0036]
3. Evaluation of waterproofness A speaker unit was manufactured using the obtained acoustic radiation plate, and was input at a rated input of 15 W using White Noise with JIS Filter. From the back of the unit, a shower (flow rate 6 l / min) was taken for 120 minutes and then left standing for 24 hours. Immediately after the shower was started, water leakage and oozing on the speaker surface, deformation and discoloration of the speaker were examined, and the rate of change in f0 after 24 hours was examined. When these changes were not observed and when the f0 change rate was less than 30%, OK was indicated, and when changes were observed or when the f0 change rate exceeded 30%, NG was indicated.
[0037]
4 Frequency characteristics before and after the waterproof test at 50 cm on the axis and 1 W input were examined for Example 1 and Comparative Examples 1 and 2. The results are shown in FIG.
[0038]
[Table 1]
(Example 2)
Blend melamine phosphate dissolved in water and perfluoro-n-octanoic acid dissolved in propylene glycol in a ratio of 20: 1 (compound weight ratio) and diluted with water until the total concentration is 30% by weight, A treatment solution was prepared. 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 speakers, and subjected to the same evaluation as in Example 1. The results are shown in Table 1 above.
(Comparative Example 1)
An acoustic radiation plate for a speaker was produced in the same manner as in Example 1 except that a treatment liquid was prepared using a water-soluble flame retardant described in Japanese Patent Publication No. 57-50399 and a silicone water repellent. The same evaluation as 1 was used. The results are shown in Table 1 and FIG.
(Comparative Example 2)
An acoustic radiation plate for a speaker was produced in the same manner as in Example 1 except that the treatment liquid was prepared using only the organic phosphorus-containing nitrogen-containing compound described in JP-A-58-1396. We used for evaluation. The results are shown in Table 1 and FIG.
(Comparative Example 3)
The sound radiation plate for speaker was produced by impregnating fluorinated resin (3% by weight with respect to nitrified cotton) into nitrified cotton (thickened to 7% with ethyl acetate) without flame retardant treatment. The same evaluation as in Example 1 was performed. The results are shown in Table 1 above.
[0039]
As can be seen 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 a toxic gas is not generated to the extent that a toxic gas is adversely affected when smoke is generated because a fluorine-containing compound generates less toxic gas than other halogen compounds. Furthermore, as is clear from a comparison between FIG. 3 and FIG. 5, the speaker member of the present invention has less distortion in the middle and low range after the waterproof test than the comparative example.
[0040]
【The invention's effect】
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 smoke generation, light weight and high elasticity, excellent waterproofness and flame retardancy Can be obtained, and a 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 binding state of a water-repellent compound, an organic phosphorus-containing nitrogen-containing compound, and cellulose fibers.
FIG. 3 is a graph showing frequency characteristics of the speaker member of Example 1 before and after the waterproof test.
FIG. 4 is a graph showing the frequency characteristics of the speaker diaphragm of Comparative Example 1 before and after the waterproof test.
FIG. 5 is a graph showing frequency characteristics of the speaker diaphragm of Comparative Example 2 before and after the waterproof test.

Claims (4)

Natural fibers molded into a predetermined shape;
Melamine phosphate,
A water repellent compound having at least one functional group selected from a perfluoroalkyl group and a fluorine-containing hydrocarbon group,
The hydroxyl group of the natural fiber and the ammonium group of the melamine phosphate are bonded by an ionic bond,
The other ammonium group of the melamine phosphate and the anion group of the water-repellent compound are bonded by an ionic bond,
Speaker component. The speaker member according to claim 1, wherein the water repellent compound further has at least one functional group selected from a hydroxyl group and a carboxyl group. The speaker member according to claim 2 , wherein the water repellent compound is selected from 2,2,2-trifluoroethanol, hexafluoroisopropanol, trifluoroacetic acid, and perfluoro-n-octanoic acid. Forming natural fibers into a predetermined shape;
Impregnating or coating the molded natural fiber with a treatment liquid containing a water repellent compound having at least one functional group selected from a perfluoroalkyl group and a fluorine-containing hydrocarbon group and melamine phosphate;
Heat-treating the natural fibers that have been molded and treated with the treatment liquid.