JP2002064892A - Method for producing speaker box - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a speaker box made of a composite material of resin and a cellulose based crushed matter and having a required rigidity, a good sound quality and a woody feeling. SOLUTION: A cellulose based crushed matter, e.g. wood powder, polystyrene and a dispersion accelerator are mixed to form a pellet-like woody synthetic material composition where the cellulose based crushed matter and polystyrene are crosslinked through the dispersion accelerator. The woody synthetic material composition is injection molded to produce a speaker box.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a woody synthetic composition comprising a crushed cellulosic material and polystyrene,
The present invention relates to a method for producing a speaker box using the woody synthetic composition. For example, polystyrene which is used in large quantities as a cabinet (outer frame) material of household electric appliances, particularly a television receiver, and cellulose such as wood flour and paper. The present invention relates to a method for manufacturing a speaker box using a woody synthetic material composition manufactured using a crushed material as a raw material. In this specification, the speaker box refers to a box that accommodates the speaker.

[0002]

2. Description of the Related Art A speaker box is a box that protects and stores speakers and other parts, is also an audio device, and can be regarded as furniture or furniture when placed indoors. It is preferable to have excellent rigidity and excellent sound quality as an acoustic device, and also have a beautiful appearance as furniture or furniture.

[0003] Among them, the characteristics required for the audio equipment include that the attenuation of the sound is accelerated in order to shorten the reverberation time, that is, that it has a large internal loss (or loss coefficient), The sound generated from
In order to avoid interference with the sound generated from the front of the speaker, the tightness of the speaker box for the low frequency range, the density (or specific gravity) of the speaker box material for the high frequency range, and the speaker If the internal volume of the box is small, the sound waves emitted from the back of the speaker will interfere, and depending on the frequency, the movement of the speaker cone will be suppressed due to the pressure difference between the inside and outside, and the bass output will be poor, By increasing the volume, it is possible to resonate the low range and obtain a bass enhancement effect. For example, a small speaker box is required to have a large internal volume (effective internal volume).

[0004] As a material for producing a speaker box requiring such characteristics, there have been conventionally used wood-based materials such as particle board and plywood, PP (polypropylene), PS (polystyrene), and the like. Resin-based materials such as PC (polycarbonate), polymethacrylate, acrylonitrile-butadiene-styrene copolymer, a mixture of these resins with an inorganic filler, and foams of these resins are used.

[0005]

A conventionally used speaker box made of a wood-based material such as a particle board or a plywood has a density and a loss coefficient required for an acoustic device and a box body. It also has the required rigidity, and furthermore, it can feel heavy, luxurious, warm, etc. from its woody feel, and when placed indoors, it harmonizes with other furniture etc. without discomfort It can withstand appreciation as furniture.

[0006] However, since such a wooden material is made of a natural material, it is susceptible to a change over time due to variations in the material and humidity.

Further, it is extremely difficult to produce a speaker box having a complicated shape from the above-mentioned woody material. For example, the space to be installed is limited as in a speaker box for a car stereo, and a shape suitable for the speaker box is limited. Such a wood-based material is unsuitable when a speaker box must be manufactured.

On the other hand, when the speaker box is made of a resin material, it is relatively easy to mold the speaker box into a desired shape, and the speaker box is widely used in fields where it is difficult to use wood materials. . In addition, since resin-based materials are generally lightweight, they are suitable, for example, for manufacturing speaker boxes mounted on vehicles as part of car stereos and the like.

However, the above-mentioned resin-based materials are relatively expensive and have insufficient rigidity as a box alone, and mica (mica), talc,
When an inorganic filler such as calcium carbonate is added, the internal loss is reduced, leading to a decrease in sound quality.

Further, the speaker box made of a resin material does not have the woody feeling of a wood material, and therefore lacks a feeling of solidness, luxury, warmth, and has a tasteless and dry atmosphere.

On the other hand, Japanese Patent Application Laid-Open No. 56-165487
In the speaker box described in Japanese Patent Laid-Open Publication No. H10-260, sound quality close to that of a wood-based speaker box can be obtained by filling a thermoplastic resin with shirasu and wood chips, thereby filling the wood-based material. But,
In the speaker box described in Japanese Patent Application Laid-Open No. 56-165487, a woody feeling is not produced regardless of the filling of wood chips.

Further, in the speaker box described in Japanese Patent Application Laid-Open No. 2-153944, an inorganic filler is mixed with a thermoplastic resin, and a chemical foaming agent is added thereto, so that the loss coefficient and the rigidity are reduced. Improved and lighter weight. However, similar to the speaker box described in Japanese Patent Application Laid-Open No.
Even the speaker box disclosed in Japanese Patent No. 39444 has no woody feeling and has a tasteless and dry atmosphere.

If the amount of cellulosic crushed material such as wood flour is simply increased in order to give a feeling of woody quality, the water supply rate and the coefficient of linear expansion increase, resulting in quality variation due to changes over time. Cannot be used as a speaker box because the desired strength cannot be obtained.

When the thickness of the speaker box is increased for the purpose of improving the rigidity of the speaker box, etc.,
The volume inside the speaker box is reduced, especially in a small speaker box, where bass output is suppressed and bass is not enhanced by resonance, resulting in poor bass output and lack of power .

Therefore, an object of the present invention is to solve the above-mentioned drawbacks in the prior art, and it is excellent in processing and formability, hardly causes variation in material and change with time, and is made of wood. A speaker box that has a sound quality equal to or better than that of a speaker box, has a woody feel, and is relatively thin and has the required rigidity even in a small speaker box, and thus can secure a sufficient effective internal volume. The purpose is to provide.

Further, another object of the present invention is to recover polystyrene molded products which are used in large quantities as household electric appliance parts, especially cabinet materials, and are discarded, and use the recovered polystyrene molded products as raw materials. By manufacturing a speaker box, it is possible to provide a high-quality speaker box as described above at low cost, and to effectively use resources.

[0017]

Means for Solving the Problems To achieve the above object, a speaker box according to the present invention comprises a step of collecting and discarding a discarded polystyrene molded product into small pieces having a long side or a long diameter of 3 mm or less [crushing step And 40 to 50% by weight of crushed pieces of the polystyrene molded product obtained by the above step,
The moisture content is within 0.3 wt% and the average particle size is 50-330.
50-60 wt% of the cellulosic crushed material of the mesh is blended, and 0.3-1.0 wt% with respect to the blend of the crushed piece of the polystyrene molded product and the cellulosic crushed material.
Is mixed with the stirring impellers 85, 86 and 87, and the mixture is gelled and kneaded by frictional heat caused by the shearing force generated at the time of the mixing. And a step of producing a kneaded material of a woody synthetic composition formed by crosslinking polystyrene (mixing / kneading step),
The kneaded material obtained in the above step was cooled and granulated (cooling / granulation step), or granulated if necessary after granulation (granulation step), granulated or granulated and granulated. It comprises a step of obtaining a woody synthetic composition, and a step of forming the woody synthetic composition obtained in the above step into a speaker box by injection molding (injection molding step) (claim 1).

The above-mentioned polystyrene molded article can be obtained by dismantling a discarded television receiver and collecting the dismantled polystyrene parts (Claim 2). As the material, wood flour can be used (claim 3).

Polystyrene is suitable for a speaker box as a household electrical appliance requiring flame retardancy, and promotes reuse of a rapidly increasing waste of a television receiver housing and the like.

Preferably, before mixing and kneading, titanium oxide is blended in an amount of 25% by weight or less based on the cellulosic crushed product (claim 4). In this case, the dispersion accelerator is replaced with the polystyrene. The crushed pieces of the parts, 0.3 to the total weight of the cellulosic crushed material and the titanium oxide
It is preferable to add 1.0 wt% (claim 5).

[0021]

Next, an embodiment of the present invention will be described below. The method for manufacturing a speaker box according to the present invention includes:
As shown in FIG. 1, the discarded television receiver is dismantled or the like, and the obtained polystyrene molded product is collected. The collected polystyrene molded product is crushed by a crusher 110,
A step of crushing into small pieces having a side of 3 mm or less by a cutter mill 120 or the like (crushing step), a crushed piece of polystyrene obtained in the above step, a cellulosic crushed substance such as wood flour or paper, and a dispersion accelerator And stirring impellers 85, 86, 8
7 is mixed by a mixer 80 provided with the above-mentioned method, and the crushed pieces of polystyrene are melted by the frictional heat generated by the shearing force at this time, gelled and kneaded, and the cellulose-based crushed product and the polystyrene are crosslinked to form a synthetic composition. A step (stirring / kneading step) of producing a kneaded material (referred to as “woody synthetic composition” in the present specification), and cooling and granulating the kneaded material with a cooling mixer 100 to produce a woody synthetic composition. A process [cooling / granulating process], a process of sizing the granulated product obtained by the process to a particle size of 8 mm or less [granulating process], if necessary, and a cooling / granulating process and, if necessary, Of the woody synthetic composition in the form of pellets obtained through the sizing step by injection molding with an injection molding machine to form a speaker box of any shape [injection molding step].

Hereinafter, a method of manufacturing a speaker box according to the present invention will be described step by step. [Raw Materials] (Polystyrene) In the method for manufacturing a speaker box of the present invention, the polystyrene used as the raw material of the speaker box is obtained by collecting a discarded polystyrene molded product.

This polystyrene is used in large quantities, for example, as a cabinet material for household appliances, and is discarded. In the present embodiment, as an example, a discarded television receiver is disassembled. Among these, the cabinet material is recovered as a polystyrene molded product, and this is used as a raw material.

(Cellulose-based crushed material) As the other main raw material of the speaker box, a virgin material obtained by crushing unused wood or the like can be used as a raw material. Cellulose-based crushed material obtained by crushing construction waste material, collected waste paper, and the like can be reused as a raw material for producing the speaker box of the present invention.

The crushed cellulosic material used as a raw material of the speaker box is a crushed wood flour or a crushed paper recovered from waste paper having a water content of 3 wt% or less, preferably 0.1 wt% or less, more preferably 0 wt%. In the present embodiment, an example in which wood flour is used as the cellulosic crushed material will be described as an example.

Wood obtained as natural wood, construction waste, etc. has an average particle size of 50 to 330 mesh (about 300 to 50 μm).
m) and dried to the aforementioned moisture content.

The wood flour can be dried by using any apparatus as long as it can be dried to the above-mentioned moisture content. In the present embodiment, as an example, the mixing and drying will be described later.
An example of drying by a mixer used in the kneading step will be described.

In FIG. 2, reference numeral 80 denotes a mixer which is also used in a mixing / kneading step described later. In the present embodiment, the mixer 80 is also a drying means for wood flour which is a cellulosic crushed material.

Reference numeral 81 denotes a mixer body, and the mixer body 8
A shaft 83, which rotates at a high speed due to the rotation of a motor (not shown), is mounted in the center of the bottom of the mixer 1 upward in the mixer 80.
4. The stirring impact blades 85, 86, and 87 are mounted, and are tightened with the tightening nut 92 from the tip of the shaft 83. The shape of each of the stirring impact blades 85, 86, 87 is not particularly limited, but in the present embodiment, the blades are symmetrical two blades.

As shown in FIG. 2, when three stirring impact blades are superimposed, the blades are composed of a total of six blades, and these six blades are equal angles (60 degrees) obtained by dividing 360 degrees into six planes. In a state of crossing each other. When a plurality of stirring impellers are provided, the total number of stirring impeller blades is 36.
It is preferable to overlap each other at an angle obtained by equally dividing 0 degrees from the viewpoint of efficiently stirring the raw materials.

When the upper lid 82 of the mixer 80 constructed as described above is opened, and wood flour is thrown in from the inlet 94 and stirred, friction caused by the shearing force generated by the rotation of the stirring impellers 85, 86 and 87. The wood flour put into the mixer 80 is heated and stirred while being heated.

In this embodiment, the mixer 80
Was used, and the stirring impeller was rotated at 800 to 900 rpm, and was dried at about 185 ° C. for about 15 minutes due to shear heat generated by the rotation of the stirring impeller, thereby reducing the water content of the wood flour to 0 wt%. .

When the wood flour is dried, titanium oxide can be put into the mixer 80 together with the wood flour. When the titanium oxide is fed at the same time as the wood flour, the surroundings of the fine wood flour or moisture evaporates. Also, a part of the titanium oxide is attached to and penetrates and fixes in some of the hollowed conduits or temporary conduits.

This titanium oxide can be blended at 25% or less with respect to the wood powder. By the addition of the titanium oxide, coloring and burning of the wood powder can be prevented. If the content of titanium oxide is 26 wt% or more with respect to the wood powder, the adsorption to the wood powder becomes somewhat difficult, which is not appropriate.

Further, the mixing of titanium oxide is preferable in order to increase the shearing force in the mixing / kneading step described later.
In addition, it has good fluidity and dispersibility in a solution, and contributes to increasing the compression modulus of the speaker box manufactured by the method of the present invention.

The drying of the wood flour does not necessarily have to be carried out by the mixer shown in FIG. 2, but may be carried out using another drying device as long as the wood flour can be dried to the above-mentioned water content. May be.

[Crushing Step] The recovered polystyrene molded product, in this embodiment, the cabinet of the television receiver is subjected to a crushing machine such as a crusher or cutter in the crushing step, and has a long side or a long diameter of 3 mm. Crushed into the following pieces:

This crushing step can be carried out by using any equipment capable of crushing the recovered polystyrene molded product to the above-mentioned size, and formed by combining crushers or crushers of the same or different types. The crushing can be performed using a crushing means. In the present embodiment, as an example, the crushing is performed by a crushing step using a twin-screw crusher (crusher 110: see FIG. 1) as a crushing means and a fine crushing means. This is performed by a fine crushing step using a single-shaft crusher (cutter mill 120) shown in FIG. Therefore, in this embodiment,
The crushing step includes two steps of a coarse crushing step and a fine crushing step, and the crushing means is constituted by combining the above-mentioned twin-screw crusher and single-screw crusher.

(1) Twin-screw crusher The twin-screw crusher used in the crushing step includes:
For example, Gainax Crusher manufactured by Horai Co., Ltd.
Alternatively, various known mono-cutters, shredders, crushers, and the like (hereinafter, these are collectively referred to as “crushers”) such as a roll crusher manufactured by Nara Machinery Co., Ltd. can be used.

In the crusher 110, for example, two axes that rotate inward each other are provided in parallel in the crusher body, and a plurality of rotary blades are provided on each axis at predetermined intervals.
The object to be crushed is cut into crushed pieces composed of appropriately large pieces by three claw blades which are meshed with each other on the outer periphery of each rotary blade of each shaft and are protruded so as to form an equal angle on the outer peripheral surface of each rotary blade. Is provided.

The polystyrene molded product supplied from the upper input port of the crusher 110 is drawn into the interior by the claw blades of the biaxial rotary blades rotating inward each other, and the outer peripheral edge of the rotary blade rotating in a meshed state. In the meantime, it is crushed and cut by the compressive force acting at the time of retraction while slitting with the continuously acting cutting force, forming coarse crushed pieces.

The crushed pieces thus formed pass through a screen provided below the biaxial rotary blade and are discharged from a discharge port. In addition, the small pieces formed by crushing in this manner are rectangular, rectangular such as square, triangular,
It is crushed into irregular shaped pieces such as trapezoids and rhombuses and discharged from the outlet.

(2) Single-Spin Grinding Machine The small pieces crushed as described above are separated by, for example, a known fine crushing means which is a single-screw crushing machine (referred to as “cutter mill” for convenience in the present specification) in the present embodiment. 3 on each side
Crushed into small pieces less than mm.

This cutter mill has a cylindrical shape having an input port 123 on the upper surface, and a cutter support 124 which is rotated in a horizontal direction by rotation driving means (not shown) is provided in the cylinder, and an outer periphery of the cutter support 124 is provided. The rotary blade 125 that is long in the vertical direction is
Three blades are provided so as to form an equal angle of degree, and the cutting edges of these three rotary blades 125 are located on the same rotation locus.

Further, the two fixed blades 126 are separated from the rotation trajectories of the cutting edges of the three rotating blades 125 by a small gap.
Is fixed to the cutter mill main body 121 at a position substantially symmetrical with the rotation locus of the cutting edge of the rotary blade 125, the inside of the cutter mill main body 121 is divided by the two fixed blades 126, the cutter support 124 and the rotary blade 125, and the input chamber 127 and the crushing chamber are crushed. A chamber 128 is formed. The charging port 123 communicates with the charging chamber 127. In addition,
The clearance between the second fixed blade 126 and the rotary blade 125 can be freely adjusted so that the object to be crushed can be cut into a desired size or, in a broad sense, crushed.

In the above-mentioned cutter mill 120, a small piece formed by crushing by the crusher 110 is inserted from the input port 123 and the cutter support 124 is rotated by a rotation driving means (not shown). 12
Although the shape and area between the rotary blade 125 and the fixed blade 126 are indeterminate, they are finely crushed into rectangular or square or other irregular small pieces such as triangles, trapezoids, or rhombuses.
At the exit of the cutter mill 120, a screen 129 made of punched metal or the like having an opening formed so as to allow passage of only the crushed pieces of the above-described size is provided, and only small pieces crushed to a long side or a long diameter of 3 mm or less are provided. It passes through this screen 129 and is collected.

The cutter mill 1 shown in FIGS.
Although 20 is shown as having a vertical axis of rotation, the cutter mill 120 used in the present invention can be any type having a horizontal axis of rotation or any other type. The configuration is not limited as long as the polystyrene molded product can be crushed to the size described above.

[Mixing / Kneading Step] The polystyrene crushed pieces 81 obtained as described above are mixed and kneaded with a cellulosic crushed material together with a compatibilizer as a dispersion accelerator.

In this embodiment, the crushed pieces of the polystyrene molded product and the compatibilizer are further charged into the mixer 80 into which the wood flour has been charged for drying as described above, and mixed and kneaded. .

The mixture of the polystyrene and the cellulosic crushed product is obtained by mixing 40 to 50% by weight of a crushed piece of a polystyrene molded product with a water content of 0.3% by weight or less, preferably 0.1% by weight, more preferably 0% by weight, Cellulose-based crushed product having a diameter of 50 to 330 mesh (about 300 to 50 μm)
0 wt%, and 0.3 to 1.0 with respect to the total weight of the cellulosic crushed material and the crushed pieces of the polystyrene part.
A wt% compatibilizer is blended.

The average particle size of the crushed cellulosic material means a particle size of 50% by weight in the percentage distribution of the cumulative weight of the crushed cellulosic material.

In the above-mentioned cellulosic crushed product, 0.3
If the water content is not less than wt%, molding becomes extremely difficult during injection molding, and the compatibility between the cellulose crushed material and polystyrene becomes poor, resulting in insufficient kneading.

In the present embodiment using wood flour as the cellulosic crushed material, the wood flour is 50 wt% of the total amount of the raw materials.
In the following cases, the resin may form a slightly large lump in the mixer 80. When the wood powder is less than 50% by weight, adsorption and fusion with the polystyrene, the dispersing accelerator, and the titanium oxide wood powder of the above-mentioned composition are performed. Fixation becomes difficult. In addition, the mechanical properties, particularly the bending strength, may be reduced, which may cause undesirable results. However, the blending amount of wood flour is 60
Raw materials can be gelled up to wt%.

On the other hand, when the amount of the wood powder exceeds 60 wt%, the wood powder is burned at the time of molding, making the molding difficult, and even if the molding can be performed, the strength is reduced.

Further, when the particle size is 50 mesh or more, the evaporation of water is not performed smoothly, and the dispersion is not performed uniformly during kneading.

When the mesh size is less than 330 mesh, special pulverization using a ball mill or the like is required, and the efficiency is poor. In addition, the structure such as a conduit in the wood flour fiber is destroyed, and it is difficult to crosslink with polystyrene. is there.

Further, when a dispersion accelerator is added in an amount of 1.0% or more, molding becomes difficult, and when a plate having a certain thickness or more is formed, an undesirable result such as a decrease in bending strength may be caused. If it is 0.3% or less, the effect of improving characteristics is not exhibited.

From the above, in this embodiment, the wood flour 50 wt%
(If the addition of titanium oxide is performed during the drying of the wood flour, the mixture of wood flour and titanium oxide is 50 wt%.)
%, And a compatibilizer was added as a dispersion accelerator in an amount of 0.5 wt% based on the total weight of the wood flour and the polystyrene.

In this embodiment, the compatibilizer is a reactive polyolefin-based oligomer (melt viscosity of about 7000 CPS: BL
A mold viscometer, a softening point of about 145 ° C .: JIS-K2531) was used.
Specifically, Sanyo Chemical Industries Umex 101
0.

In this step, the material charged into the mixer 80 is heated to about 210 ° C. by the frictional heat generated by the shearing force at the time of stirring by the rotation of the stirring impact blades 85, 86, 87, and the polystyrene is melted. Then, the mixture is gelled and kneaded with the wood flour and the compatibilizer.

At this time, the polystyrene does not form a large lump due to the wood powder in the raw material, and does not agglomerate during mixing and dispersion, but gels into a clay just before coagulation, and then forms a lump of about 10 to 100 mm in diameter. Kneading material ".

In other words, this lump means that the individual wood flour evaporates the entire surface of the wood flour alone and the moisture of the fine wood flour,
Some of the resin also penetrates and solidifies and adheres to some of the hollowed conduits or temporary conduits, and recrystallizes between the resins fused to the adjacent wood flour via a compatibilizer, or
Although the resin is recrystallized to form a crosslinked state in which adjacent fine particles are solidified with each other, the bonding of the whole mass itself is brittle. Therefore, the kneading material formed in this step is a good material that can be kneaded more efficiently during the injection molding described below, and is a good material that reduces the frictional resistance of wood powder particularly during the injection molding.

To describe this step in more detail, since the water content of the wood flour is 0.3 wt% or less, the performance of the compatibilizer to improve the dispersibility is further promoted. Is dispersed at a uniform density in the resin as viewed from the wood powder, and is kneaded and melted in such a manner as to be easily impregnated into the wood powder as viewed from the polystyrene and to completely surround the outer periphery of the wood powder.

[Cooling / Granulation Step] The above-mentioned mixer 80
The kneaded material formed in the above step is cooled while stirring and granulated into a granulated product having a diameter of 25 mm or less, and if necessary, sized using a cutter mill to a particle size of 8 mm or less. "Woody synthetic composition".

In FIG. 4, reference numeral 100 denotes a “cooling mixer” for cooling and granulating the above-described kneaded material to produce a “granulated material”.

Reference numeral 101 denotes a mixer body, which covers the upper surface,
On the other hand, a discharge port 107 is provided at the lower end, and the discharge port 107 is provided to be freely opened and closed by a valve 106. Mixer body 1
A jacket 102 is formed in the outer peripheral wall of the cooling mixer 100, and cooling water is constantly supplied from the water absorption pipe 108 to the drain pipe 109 in the jacket 102 so that the temperature of the kneading material in the cooling mixer 100 is cooled to near the melting point. ing.

At substantially the center of the upper wall of the mixer body 101, an arm 103 is rotatably supported in a substantially horizontal direction.
A stirring and crushing blade 104 is supported at the tip of the arm 103, and the stirring and crushing blade 104 is of a screw type in this embodiment.

An inlet 113 is provided on the upper wall of the mixer body 101, and the outlet 113 is connected to the discharge duct 93 of the mixer 80 described above.

The kneaded material formed in the mixer 80 described above is introduced into the mixer main body 101 from the introduction port 113 through the discharge duct 93. The charged kneading material is cooled with stirring and granulated to a diameter of about 25 mm or less to form a "granulated material". The granulated material is discharged from the discharge port 107 by opening the valve 106.

The kneaded material cooled by the cooling mixer 100 does not need to be lowered to a temperature lower than the freezing point of polystyrene in the raw material, that is, the melting point or less. What is necessary is just to cool to about 10 degreeC higher than the melting point of the resin in a kneading material.

The cooling / granulation step is not limited to the cooling mixer 100 as described above, but is provided with a stirring blade for stirring the kneaded material in the mixer main body and on the outer peripheral wall surface in the mixer. What is necessary is just to be provided with a cooling means such as a jacket as described above.

In the present embodiment, a cooling mixer (manufactured by Kawata) having a capacity of 1050 liters is used in the cooling / granulating step, and 50 kg of the kneading material is put into the mixer body of the cooling mixer. Stir while cooling.

For cooling and stirring, cooling water was introduced into the jacket at a rate of 100 liters per minute, cooled to about 100 ° C. or less, and the stirring blade was rotated at 120 rpm to perform stirring and cooling for about 10 minutes. A granulated product having a diameter of about 25 mm was obtained.

[Granulation Step] The “granulated material” obtained in the above cooling / granulation step is preferably further sized to a diameter of about 8 mm or less.

As the sizing means used in the sizing step, for example, the "cutter mill" used in the crushing step described above can be used. At this time, by setting the opening of the screen 129 provided in the cutter mill to a diameter of 8 mm or less, only the woody synthetic composition granulated to a diameter of 8 mm or less is discharged from the cutter mill.

The granulating step is not always necessary, and may be omitted depending on the size of the granulated product obtained in the cooling and granulating step.

Further, in this embodiment, an example in which the cutter mill 120 shown in FIG. 3 is used as the sizing means has been described. The particle size is not limited to the cutter mill shown, and may be adjusted using any other device.

[Process of Forming Speaker Box] The woody synthetic composition in pellet form obtained as described above is charged into a heating cylinder via a hopper or the like provided in an injection molding machine and heated.

The woody synthetic composition heated in the heating cylinder was melted and fluidized by heating, and was satisfactorily kneaded and melted before flowing into the heating cylinder by injection of the plunger and being injected into the mold. The woody synthetic composition is cooled in a mold and formed into a speaker box having a desired shape.

The processing conditions for injection molding in the present embodiment are as follows. Injection molding machine: Toshiba Machine Co., Ltd .: IS220 GNH Resin temperature: 185 ° C Injection pressure: 7.21 MPa (73.5 kg / cm ² ) Mold temperature: 30 ° C Injection time: 12 seconds Cooling time: 40 seconds

As described above, as an example, FIGS.
The speaker box 1 having the shape shown in FIG. The speaker box 1 includes a speaker box body 2 forming upper and lower surfaces, side surfaces, and a back surface of the speaker box 1;
The speaker box 1 is formed by a lid 3 forming the front surface of the speaker box 1, and a projection 4 formed on the inner peripheral edge of the opening 2 a of the speaker box body 2 is inserted into the opening 3 a of the lid 3. Is formed.

The speaker box has a height of 212 mm, a width of 132 mm, and a depth of 181 mm, for example, and the thickness of the speaker box body 2 and the lid 3 is about 2 mm.

The speaker box 1 molded by the injection molding in this manner has the same strength as the conventional resin speaker box due to the above-mentioned relatively thin thickness, and therefore, the effective internal volume can be widened. As well as having a woody texture that gives people peace and calm.

Further, with respect to the sound quality characteristics, a sound color closer to that of a speaker box using a wood-based material can be provided as compared with a conventional resin molded product by improving the loss coefficient due to the large amount of wood powder mixed therein. It has become something.

[0085]

According to the configuration of the present invention described above, the speaker box of the present invention has the following remarkable effects.

Since it is made of a synthetic material of polystyrene, a cellulosic crushed material and a dispersion accelerator, it is easy to process into a desired shape, and a large amount of the cellulosic crushed material is mixed, and a good woody feeling is produced, so that it is beautiful. The speaker box was able to obtain the appearance and endure appreciation as furniture, furniture and the like.

Further, the strength does not decrease even when a relatively large amount of cellulosic crushed material is mixed, so that the wall thickness can be made relatively thin, the effective internal volume in the speaker box can be widened, and the cellulose type having a large loss coefficient can be obtained. Inclusion of a large amount of crushed material also led to an improvement in the loss factor of the speaker pox itself, shortening the reverberation time, and obtaining a speaker box with good sound quality.

Cellulose-based crushed materials such as wood flour and paper are inexpensive as compared with polystyrene. Therefore, the production cost of the speaker box can be reduced by reducing the amount of the thermoplastic resin used. In particular, when dismantling and recovering cellulosic crushed materials from discarded home appliances, for example, discarded television receivers, it can reduce the cost of raw materials and provide effective use of resources. Becomes

[Brief description of the drawings]

FIG. 1 is an explanatory view schematically showing a manufacturing process of the present invention.

FIG. 2 is a sectional view of a main part of a mixer.

FIG. 3 is a schematic perspective view of a cutter mill.

FIG. 4 is a sectional view of an essential part of the cooling mixer.

FIG. 5 is a right side view of the speaker box in a state where a speaker box body and a lid are separated.

6A and 6B show a lid body, wherein FIG. 6A is a front view and FIG. 6B is a rear view.

7A and 7B show a speaker box main body, wherein FIG. 7A is a front view and FIG. 7B is a rear view.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Speaker box 2 Speaker box main body 2a Opening (of speaker box main body) 3 Lid 3a Opening (of lid) 4 Projection part 80 Mixer (mixing / kneading means) 81 Mixer main body 82 Upper lid 83 Shaft 84 Scraper 85, 86, 87 Stirring impact blade 88 Discharge port 89 Lid 93 Discharge duct 100 Cooling mixer (cooling / granulating means) 101 Mixer body 102 Jacket 103 Arm 104 Stirring and crushing blade 105 Motor 106 Valve 107 Discharge port 108 Water suction port 109 Drain pipe 110 Crusher (rough crushing) Means) 120 cutter mill (fine crushing means, sizing means) 121 cutter mill main body 122 lid 123 input port 124 cutter support 125 rotating blade 126 fixed blade 127 input chamber 128 crushing chamber 129 screen

Continued on the front page (72) Inventor Maki Shirai 2-25-1, Kawatari Mizutani B201 No. 2-25-1, Kawatari, Gifu-shi, Gifu F-term (reference) 2B260 AA20 BA01 BA07 BA15 BA18 BA26 BA27 CC01 CD06 CD13 EA12 EB02 EB04 EB06 EB08 EB12 EB21 EC18 5D017 AD02 AD04 AD05

Claims (5)

[Claims] 1. A step of collecting and discarding a discarded polystyrene molded product into small pieces having a long side or a major axis of 3 mm or less; and a crushed piece 4 of the polystyrene molded product obtained by the step.
0 to 50% by weight, the moisture content is within 0.3% by weight, and the cellulosic crushed product having an average particle size of 50 to 330 mesh is 50 to 50%.
60% by weight, and 0.1% based on the blend of the crushed piece of the polystyrene molded article and the crushed cellulosic material.
3 to 1.0 wt% of a dispersion accelerator is mixed, and the mixture is mixed by a stirring impeller and gelled and kneaded by frictional heat due to shear force generated during the mixing, and the cellulose crushing is performed via the dispersion accelerator. Producing a kneaded material of a woody synthetic composition formed by cross-linking a product and polystyrene; cooling and kneading the kneaded material obtained in the step; or granulating and granulating and sizing; and granulating by the step. Alternatively, a method for producing a speaker box, comprising a step of molding a granulated and sized woody synthetic composition into a speaker box by injection molding. 2. The method for manufacturing a speaker box according to claim 1, wherein the polystyrene molded article is collected from a discarded television receiver. 3. The method according to claim 1, wherein the cellulosic crushed material is wood flour. 4. The composition according to claim 1, wherein titanium oxide is blended in an amount of 25% by weight or less based on the crushed cellulosic material.
3. The method for manufacturing a speaker box according to claim 3. 5. The method according to claim 1, wherein the dispersing agent is incorporated in an amount of 0.3 to 1.0% by weight based on the total weight of the crushed pieces of the polystyrene component, the crushed cellulosic material and the titanium oxide. A method for manufacturing the speaker box according to claim 4.