JP2009091678A - Method and apparatus for producing fine natural fiber, fine natural fiber produced by this production method, and speaker component using this fine natural fiber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that the degree for making a fiber finer is insufficient in the current condition although the making finer of the fiber is studied for enhancing the sound quality in a paper-made speaker component used in various kinds of acoustic apparatus. <P>SOLUTION: The fine natural fiber having a BET specific surface area of 1 m<SP>2</SP>/g or more can easily be produced by a production method including a step for beating a natural fiber by a biaxial kneading machine 20 such as a pressurized kneader, and a step for making the fiber finer by a bead mill 21. The speaker with the high sound quality can be achieved using the fiber made finer for the speaker component such as a diaphragm. In addition, the high productivity can be ensured and reduction in the price of the speaker can be achieved. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a component of a speaker used in fine natural fibers and various acoustic devices.

  With respect to recent electronic equipment such as audio equipment and video equipment, the performance has been dramatically improved as compared with the prior art due to remarkable progress in digital technology.

  Therefore, due to the improvement in performance of the electronic devices described above, there is a strong demand from the market to improve the performance of speakers used in these electronic devices.

  On the other hand, for loudspeakers whose performance is strongly demanded by the market, it is indispensable to improve the performance of vibration components, mainly diaphragms, which occupy a large weight that determines the sound quality of the speaker components. It is.

  As a part of improving the performance of vibration components centering on this diaphragm, sound creation and characteristic creation that satisfies the user needs required for each field and for each application are very important.

  The creation of sound and characteristics that satisfy these user needs is a papermaking part that has the advantage of fine adjustment of the characteristics and sound quality as a speaker, and the development of this papermaking part has attracted attention.

  A conventional manufacturing method and production equipment will be described with reference to FIG. 3 using a diaphragm which is one of speaker components as an example.

  FIG. 3 is a conceptual diagram showing a conventional method for producing a speaker papermaking diaphragm and production equipment.

  As shown in FIG. 3, reference numeral 1 denotes a beater. The material 10 of the speaker papermaking diaphragm is put into a beater 1 containing water, and the rotating rod 2 is rotated so that the beating means A takes several days. Beat in detail.

  Next, the beaten material is made by paper making means B onto the mold 3 and the wire mesh 4 disposed thereon to discharge only moisture, deposit the material, and form a diaphragm for a speaker. Form.

  Next, the deposited speaker diaphragm material is heated and pressurized by the pressurizing means C to evaporate the remaining water.

  Next, the punching means D is used to punch out the outermost peripheral portion that is not required and the central hole portion for inserting the voice coil with the mold 5.

  Thus, a conventional speaker papermaking diaphragm is completed.

  The press vibration plate production facility has been described above. However, there is a production facility as an oven vibration plate that is not pressed and dried for about 1 to 2 days, a so-called non-press vibration plate.

As prior art document information relating to the invention of this application, for example, Patent Document 1 is known.
Japanese Patent Laid-Open No. 5-211696

  While the audio and video industries have achieved dramatic performance improvements due to the significant advances in digital technology described above, their products tend to be low-priced and are used in electronic equipment such as audio and video equipment. The market demand for lowering the price is also remarkable.

  Conventional speaker vibration parts that can satisfy user needs are mainly paper-making parts formed by making a pulp material.

  The papermaking part, in particular the papermaking diaphragm, is preferably rigid. For this reason, miniaturization of the fibers before papermaking leads to stiffening of papermaking parts, and has been actively studied.

  Conventionally, a beater, a disk refiner, or the like is used in the papermaking material beating process. However, it takes time to refine by this method, and in order to increase the beating degree, the blade is directly applied to the fiber, and even if a refined fiber is obtained, the fiber length is short and entangled after papermaking. Large rigid parts cannot be obtained.

On the other hand, the method disclosed in Patent Document 1 can feather the fiber surface without shortening the fiber length, but the efficiency is very poor, and it is practically impossible to make the BET specific surface area 1 m ² / g or more. is there.

  Moreover, the method of patent document 1 needs to process repeatedly, and a manufacturing cost becomes high.

  The present invention solves the above-described problems, and is a method for obtaining a fiber for obtaining a rigid paper-making part, and an object of the invention is to provide a speaker paper-making part manufacturing method and production equipment capable of shortening the manufacturing time. Is.

  That is, it is an object to provide a papermaking part for a speaker having a high degree of freedom in adjusting the characteristics and sound quality as a speaker with high productivity and realizing a reduction in price.

  In order to solve the above-mentioned problems, the present invention comprises a beating process in which a natural fiber is refined by a biaxial kneading apparatus, and a refinement process in which refinement is performed by a bead mill after the beating process. Manufacturing method.

And it is set as the manufacturing method of the refined natural fiber which refined | miniaturized BET specific surface area to 1 m < ² > / g or more.

  In order to process the natural fiber, the natural fiber is beaten with a biaxial kneader such as a pressure kneader. In this state, the fiber length of the natural fiber itself at the cell level is maintained.

  Then, it is set as the manufacturing method which refines | miniaturizes a natural fiber using a bead mill.

  The aforementioned pressure kneader is a device that is generally used for mixing a mixture when the main material is a resin or rubber material, but can also be used for beating natural fibers.

  In the pressure kneader, as described above, the fiber length of the natural fiber itself is maintained at the cellular level, and the entanglement of the fiber when making paper is increased compared to the fine processing by a cutting machine such as a cut mill. It is possible to provide.

However, microfabrication cannot be achieved only by processing with a pressure kneader. Therefore, by performing bead mill treatment after the pressure kneader treatment, it is possible to obtain a refined natural fiber having a BET specific surface area of 1 m ² / g without greatly impairing the fiber length.

  For example, in a pressure homogenizer, the small orifice diameter is small, and the fibers are clogged in the pressure homogenizer. Therefore, it is impossible to increase the BET surface area while maintaining the fiber length.

As in the present invention, at least two steps of a beating process of processing natural fibers with a biaxial kneader such as a pressure kneader and a subsequent refinement process of natural fibers with a bead mill are essential. Fine fibers having a BET specific surface area of 1 m ² / g or more can be obtained.

  Paper-making parts using fine fibers are extremely rigid and light. For example, when used for a speaker diaphragm, the speaker has a high sound pressure and a wide reproduction band.

  In this method, the natural fiber becomes a feather-like fine fiber because the friction between the fibers in the pressure kneader and the friction between the beads and the natural fibers and the natural fibers in the bead mill are the principle of miniaturization. Scale-up at the time of manufacture is easy, and the time for manufacturing feather-shaped fine fibers can be shortened.

  In addition, this feather-shaped fine fiber can be applied to various papermaking parts for speakers, can ensure high productivity, and can reduce the price of speakers, and its industrial value is extremely high. It ’s great.

  Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1)
Hereinafter, the present invention will be described using the first embodiment.

  FIG. 1 is a conceptual diagram showing a speaker papermaking diaphragm manufacturing method and production equipment according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of a diaphragm which is a speaker component using refined natural fibers obtained by this manufacturing method and production equipment.

  1 and 2 will be described.

  In FIG. 1, E and F are refined beating means, E is a beating means, and F is a refined means. Reference numeral 20 denotes a pressure kneader which is a biaxial kneading device. The material 10 of the speaker papermaking diaphragm is placed in the pressure kneader 20 and rotated to be finely beaten.

  Next, the beaten material is put into a bead mill 21 which is a miniaturization apparatus, and rotated to collide with the beads to be finely pulverized and refined.

  Next, the finely beaten material is made by paper making means B on the mold 3 and the metal mesh 4 disposed thereon to discharge only moisture, deposit the material, and serve as a speaker diaphragm. Form into shape.

  Next, the deposited speaker diaphragm material is heated and pressurized by the pressurizing means C to evaporate the remaining water.

  Next, an unnecessary outermost peripheral portion and a central hole portion for inserting the voice coil are punched by the die 5 by the punching means D.

  Thus, the speaker papermaking diaphragm shown in FIG. 2 is completed.

  In the above, the manufacturing method and production equipment of the press diaphragm have been described. However, it may be a production equipment as a so-called non-press diaphragm, which is an oven diaphragm that is dried for about one to two days without pressing.

  Moreover, although the manufacturing method and production equipment of a diaphragm were demonstrated as a speaker component, it can implement | achieve with the same manufacturing method and production equipment also about a papermaking type dust cap and a subcone.

  There are no particular restrictions on the natural fibers used in the present invention, but in the case of sheet-like pulp that has undergone a processing process at a paper manufacturer, it is possible to spend time with a pressure kneader or the like even when a biaxial kneader is not used or with a beater. However, it is more effective when used for broom-like natural fibers such as bamboo fibers.

  The advantage of using a pressure kneader or the like in the present invention is that it can be processed regardless of the original fiber form. Furthermore, it is an optimal way to increase the friction between the fibers, not for the purpose of mixing, and to make the natural fibers fluffy, i.e. not cleaved, but have a fluffy surface.

  In the present invention, the fibers feathered with a biaxial kneader such as a pressure kneader need to be feathered with a stronger shearing force with a bead mill. As described above, the bead mill can also promote feathering without shortening the fiber length by friction between the bead fibers or between the fibers.

Although the degree of feathering can be controlled by the type and amount of beads, in the case of natural fibers containing a large amount of cellulose, it is possible to sufficiently process refined fibers having a BET specific surface area of 1 m ² / g or more with inexpensive glass beads. it can.

  The refined fiber produced in the present invention preferably has an average fiber length of 0.5 mm or more. More preferably, it is 0.7 mm or more. By setting this fiber length, sufficient entanglement between fibers can be given during papermaking.

  There are no particular restrictions on the natural fibers used in the present invention, but bamboo fibers having a multi-layer structure with a four-layer surface are preferred because feathering due to friction can be realized efficiently.

  Since the natural fiber of claims 2 to 4 obtained by the manufacturing method of claim 1 of the present invention provides a rigid and light papermaking part, the diaphragm for speaker, the subcone for speaker, and the dust cap for speaker It is useful to use for papermaking parts for speakers, etc.

  It is particularly suitable for speaker diaphragms that require high rigidity and light weight.

  The method using the finely beaten natural fibers of claims 2 to 4 is not particularly specified.

  Preferable examples include a method of mixing and mixing with other natural cellulose and finishing it into a speaker papermaking part, or a method of applying to one or both surfaces of the papermaking part by a known means such as dipping, spraying or suction deposition. Can be mentioned.

  EXAMPLES Examples of the present invention will be described below, but the present invention is not limited at all.

Example 1
500 g of bamboo fiber having a length of about 10 cm was treated with a 3-liter pressure kneader at a rotation speed of 25 rpm for 20 minutes.

  The average fiber length after the treatment was 2.5 mm, and the Canadian standard beating degree was 750 ml.

  This was made into an aqueous dispersion having a concentration of about 3%, and 100 g of glass beads were placed in a 3-liter bead mill and treated for 20 minutes.

  The average fiber length of the obtained fiber was 1 mm.

The Canadian standard beating degree was not measurable, and the BET specific surface area was 2.22 m ² / g.

(Comparative Example 1)
The pressure kneader treated product of Example 1 was made into a 1% aqueous dispersion and then treated with a pressure homogenizer.

  As a result, the fibers were clogged and could not be processed.

(Comparative Example 2)
Bamboo fibers having a length of about 10 cm were cut to about 0.5 mm, made into a 1% aqueous dispersion, and circulated 5 times under a pressure of 50 MPa with a pressure homogenizer.

The resulting fiber had an average fiber length of 0.42 mm, a Canadian standard beating degree of 80 ml, and a BET specific surface area of 0.95 m ² / g.

(Comparative Example 3)
The bamboo fiber cut to 0.5 mm in Comparative Example 2 was treated with a bead mill in the same manner as in Example 1. Average fiber length was 0.34 mm, Canadian standard beating degree was not measurable, and BET specific surface area was 2.1 m ² / g.

(Example 2)
A flat plate and a speaker diaphragm having a diameter of 16 cm were produced using 90 wt% of the pressure kneaded product in the middle of Example 1 and 10 wt% of the refined fiber of Example 1.

  When the flat plate was measured, the sound velocity was 3500 m / s to 4000 m / s.

(Comparative Example 4)
A flat plate and a 16 cm diameter speaker diaphragm were produced using only the pressure kneaded product in the middle of Example 1.

  The measured sound speed was 3000 m / s to 3200 m / s.

(Comparative Example 5)
A wood pulp was beaten to 700 ml with a beater to produce a flat plate and a speaker diaphragm.

  The measured sound speed was 2300 m / s to 2500 m / s.

(Example 3)
The flattened fiber and the diaphragm of Comparative Example 4 were sprayed with the refined fiber of Example 1 having a weight of about 0.3 g after drying.

  The sound speed of the flat plate was 3800 m / s to 4500 m / s.

(Sound quality evaluation)
After assembling the loudspeakers using the diaphragms of Example 2, Comparative Example 4, Comparative Example 5, and Example 3, a trial evaluation was conducted with five persons.

  In terms of evaluation, a) the clearness of sound, b) the force of sound, and c) the moist feeling of sound were evaluated with 9 points for each of 3 points and a total of 45 points.

  Example 2 was 39 points, Comparative Example 4 was 30 points, Comparative Example 5 was 21 points, and Example 3 was 41 points.

  From the above results, it has been clarified that a high-quality speaker can be realized when the refined fiber obtained by the manufacturing method according to the present invention is used for a papermaking part for a speaker.

  Moreover, the construction method of the present invention can be easily scaled up, can provide a low-cost speaker papermaking component, and can contribute to cost reduction of the speaker.

  The speaker diaphragm manufacturing method according to the present invention can realize a high sound quality speaker by using finer fibers for speaker papermaking parts. Therefore, it can be applied to various acoustic devices that require both high sound quality and low cost. The present invention can be applied to a production method and production equipment for fine natural fibers and speaker components used.

The conceptual diagram which shows the manufacturing method and production facility of the papermaking diaphragm for speakers of one Embodiment of this invention Sectional drawing of the diaphragm for speakers of the present invention Schematic diagram showing a conventional speaker papermaking diaphragm manufacturing method and production equipment

Explanation of symbols

A Beating means B Paper making means C Pressing means D Pulling means E Beating means F Finening means 1 Beater 2 Rotating rod 3 Mold 4 Wire net 5 Mold

Claims (9)

A refined natural fiber manufacturing method, wherein the refined natural fiber manufacturing method comprises a beating step of beating natural fibers with a biaxial kneader, and a refinement step of refining with a bead mill after the beating step. A method for producing refined natural fibers comprising a BET specific surface area of 1 m ² / g or more. A refined natural fiber produced by the method for producing a refined natural fiber according to claim 1. The refined natural fiber according to claim 2, wherein the fiber length of the refined natural fiber is 0.5 mm or more. The refined natural fiber according to claim 2 or 3, wherein the refined natural fiber is bamboo fiber. A speaker component using the refined natural fiber according to claim 2. The speaker component according to claim 5, wherein the speaker component is a diaphragm. A speaker component having a multilayer structure in which the fine natural fiber according to any one of claims 2 to 4 is applied to one or both sides of the speaker component according to claim 6. A speaker component comprising the refined natural fiber according to any one of claims 2 to 4 in an amount of 3 wt% or more and 20 wt% or less. Production equipment for refined natural fibers, the production equipment for refined natural fibers comprising refinement means for beating using a biaxial kneader and refinement means for refinement using a bead mill Facility.

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