JP3336566B2 - Speaker diaphragm and manufacturing method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a speaker diaphragm in which a non-woven fabric is impregnated with at least a thermosetting resin and molded and cured, and a method of manufacturing the same.

[0002]

2. Description of the Related Art A conventional speaker diaphragm using a thermosetting resin as a matrix is based on a plain woven fabric of a rigid reinforcing fiber such as ceramic or glass, and an epoxy resin is mainly used as a matrix resin. I was

However, ceramic or glass as a base material has a large elastic modulus but is rigid, so that the internal loss is extremely small, and the internal loss of the matrix resin is small and the toughness is small. Large and steep resonance occurred, and it could not be used as a speaker for all bands (full range). Furthermore, since it is a woven fabric, the change in physical properties due to the direction of weaving is large, fillers such as mica are not uniformly dispersed in the resin due to steric hindrance of the weave, and misalignment must occur during molding. There were problems such as the generation of a part without fibers in the product.

[0004] On the other hand, there is a method of forming a speaker diaphragm by fusing thermoplastic resin fibers by hot pressing. However, a resin material which can be heat-fused generally does not have a very high elastic modulus, and thus a speaker diaphragm is formed. There were disadvantages that the characteristics were insufficient and the heat resistance was low.

In view of the above, various types of speaker diaphragms have been proposed, in particular, in which a non-woven fabric made of organic fibers having a high elastic modulus is bound with a matrix resin or a binder. That is, Japanese Patent Application Laid-Open No. 50-123330 proposes a speaker diaphragm obtained by molding and curing a non-woven fabric made of a non-woven fabric made of a high-modulus organic fiber or the like and coated with a thermosetting resin. Japanese Patent Application Laid-Open No. 2-228197 proposes a speaker diaphragm made of a paper-like material obtained by forming a high modulus organic fiber or the like together with aramid pulp. Japanese Patent Application Laid-Open No. 58-137394 proposes a speaker diaphragm obtained by forming a high elastic modulus organic fiber together with a polyester fiber into a web and then thermoforming a heat-sealed nonwoven fabric.

[0006]

However, since the loudspeaker diaphragm described above does not contain a pulp component when the nonwoven fabric is formed, the strength of the nonwoven fabric after the papermaking is low, and it cannot be rolled or handled. It was not practical due to manufacturing problems such as difficulty. In addition, since the speaker diaphragm does not include the matrix resin, the internal loss is increased but the elastic modulus is insufficient, and it is considered that the characteristics of the high elastic modulus organic fibers are not sufficiently utilized. Further, since the pulp component is contained, it is difficult to control the physical properties, and the physical properties are sometimes impaired. Further, in the above-mentioned speaker diaphragm, since the orientation of the fibers occurs when the fibers are formed into a web, the non-woven fabric obtained by heat-sealing the fibers tends to cause anisotropy, which tends to cause acoustic distortion of the speaker diaphragm.

[0007] In addition to the above, as a method of forming a high elastic modulus organic fiber or the like into a non-woven fabric, there are a chemical bond method in which fiber intersections are bonded with an adhesive, and a needle punch method in which fibers are entangled in a thickness direction with a needle. However, the speaker diaphragm manufactured using the nonwoven fabric obtained by these,
In the former, the fibers of the nonwoven fabric are firmly bonded to each other, so that wrinkles and cracks are likely to occur during molding.In the latter, since there is no tangling in the horizontal direction during manufacturing, the anisotropy in the vertical and horizontal directions is large, and the difference in elastic modulus is small. This is likely to cause acoustic distortion of the speaker diaphragm.

Accordingly, an object of the present invention is to provide a speaker diaphragm which has good moldability, is easy to manufacture, and has low anisotropy such as elastic modulus while utilizing the characteristics of organic fibers, and a method of manufacturing the same. Is to do.

[0009]

To achieve Means for Solving the Problems] This object, the present inventors while changing the kind of nonwoven fabric, it was intensively investigated various physical properties and moldability of the resulting speaker diaphragm, etc., the hydroentangled method Manufactured, with high modulus
Organic fibers, mainly machine fibers, are randomly entangled
It has been found that the above object can be achieved by using a non-woven fabric that is mechanically bonded , and the present invention has been completed. That is, the characteristic configuration of the speaker diaphragm of the present invention is that the non-woven fabric is formed by impregnating at least a thermosetting resin.
A hardened speaker diaphragm , wherein the nonwoven fabric is
Is produced by a fluid entanglement method and has a high elastic modulus
Organic fibers mainly composed of fibers are machined by random entanglement
It is a thing which was combined .

The nonwoven fabric can be manufactured by various manufacturing methods, but it is more preferable that the nonwoven fabric be manufactured by a fluid entanglement method from the viewpoint of the operation and effect described later.
Here, the fluid entanglement method refers to a method of injecting a high-pressure water flow or the like, intertwining the fibers, and mechanically joining the fibers,
Sometimes called the spunlace method.

It is preferable that the organic fibers are mainly composed of organic fibers having a high elastic modulus, from the viewpoint of the operation and effects described later.

Further, the organic fiber has a volume fiber content of 1%.
It is more preferable that it is contained in the range of 0 to 40% from the effects and effects described later.

On the other hand, a characteristic feature of the production method of the present invention is that at least a thermosetting resin composition is applied and impregnated to a nonwoven fabric which is mechanically bonded by random entanglement of organic fibers, and then the thermosetting resin composition is thermoset. And a step of performing thermosetting of the conductive resin composition in a mold. Here, the thermosetting resin composition refers to a composition containing a thermosetting resin and a component for curing the thermosetting resin, and may further contain various additives.

[Function and Effect] According to the characteristic configuration of the speaker diaphragm of the present invention, the nonwoven fabric is fluid-entangled.
The organic fibers are mechanically bonded by random entanglement of organic fibers mainly composed of high elasticity organic fibers, so that the orientation of the organic fibers has no anisotropy, and the elastic modulus of the obtained speaker diaphragm, etc. Difference is unlikely to occur. In addition, the nonwoven fabric is mechanically bonded by entanglement, so that the contact points of the fibers are not restrained. It can be rolled and subjected to a continuous process. Furthermore, since the thermosetting resin firmly holds the organic fibers as a matrix after molding and curing, the characteristics of the organic fibers can be utilized. As a result, it was possible to provide a speaker diaphragm which has good moldability and is easy to manufacture while making use of the characteristics of the organic fiber, and has a small anisotropy such as an elastic modulus.

Furthermore, the the organic fibers are those composed mainly of high modulus organic fibers, high modulus organic fiber high high modulus, despite having a tensile strength, etc., applications in terms of processability However, according to the present invention, as described above, the thermosetting resin can make use of the soot of the high-modulus organic fiber, and thus is a preferred embodiment.

Further, since the nonwoven fabric is one produced by fluid entangling method, which mechanically coupled by random entanglement of the organic fibers can be easily obtained, Moreover, Ya suitable thickness for the loudspeaker diaphragm This is a preferred embodiment because it is easy to obtain one with a high density.

The organic fiber has a volume fiber content of 10 to 4;
When the content is within the range of 0%, as shown in the results of the examples described later, the Young's modulus increases at the inside of the range limit at the boundary of the range, and conversely, at the outside of the range limit. In this case, the Young's modulus is greatly reduced, resulting in undesirable physical properties as a speaker diaphragm. In other words, the present inventors experimented on a critical change in the relationship between the volume fiber content of organic fibers and the Young's modulus of a speaker diaphragm using a nonwoven fabric mechanically bonded by random entanglement of organic fibers. Found by

On the other hand, according to the production method of the present invention, a speaker diaphragm having good moldability, easy production, and low anisotropy such as elastic modulus is obtained by utilizing the characteristics of the organic fiber by the above-mentioned action. Could be provided.

[0019]

Embodiments of the present invention will be described below. The non-woven fabric used in the present invention is mechanically bonded by random entanglement of organic fibers, and does not use a binder or a fused fiber. It has features. Examples of the method for producing such a nonwoven fabric include various methods such as a fluid entanglement method using various liquids such as water, or various gases such as air, and a method of mechanically entangled organic fibers randomly. As mentioned in the effect section,
Fluid entanglement is preferred. Various products are commercially available as the nonwoven fabric obtained by the hydroentanglement method or the like.

The organic fiber used in the present invention preferably has a fiber diameter of about 1.0 to 3.0 denier, and the nonwoven fabric preferably has a basis weight of 50 to 100 g / m ² . In addition, the fiber length is important in mechanically binding organic fibers by random entanglement, and from such a viewpoint, the fiber length is preferably 5 to 60 mm, more preferably 35 to 40 mm.

As the organic fiber, a high elastic modulus organic fiber, an organic fiber having a higher elastic modulus as compared with a thermosetting resin, or the like is preferably used. Organic fibers are preferred. Examples of the high elastic modulus organic fiber include various organic fibers having a higher elastic modulus than glass fiber, such as para-oriented amide fiber (coparaphenylene / 3,4'oxydiphenylene terephthalamide / trademark: Technora), PPTA (Polyparaphenylene terephthalamide / trademark: Kevlar) and the like. The difference between para-oriented amide fiber and PPTA is particularly in water resistance.
Since the strength retention (initial value 100) with respect to the initial values after 0% and 400 hours is significantly different from 100 to 20, the former can be said to be a high elastic modulus organic fiber suitable for the hydroentanglement method.

Other examples of high modulus organic fibers include wholly aromatic polyester, high modulus polyethylene, polyparaphenylene benzobisthiazole (PBT), polyparaphenylene benzoxazole (PBO), polyparabenzimidazole (PBI) and the like. And a hetero-containing ring-containing aromatic polymer.

In the present invention, organic fibers other than high-modulus organic fibers can be used. For example, thermoplastic resin fibers such as saturated polyester, polypropylene, polyamide, polyvinyl acetal (vinylon), and polyacrylonitrile; Various natural fibers and the like can be used. It is also possible to use these organic fibers in combination with high elastic modulus organic fibers. In this case, if the amount exceeds 30% by weight, the Young's modulus is greatly reduced.
It is appropriate to use no more than% by weight.

As the thermosetting resin, an unsaturated polyester resin, an epoxy resin, a phenol resin, a polyimide resin or the like is used. However, since the unsaturated polyester resin undergoes a radical polymerization reaction, a reaction gas causing bubbles is generated. In addition, the curing reaction is possible at a relatively low temperature of about 100 ° C., and the fiber is not damaged, and the curing is completed in seconds.

A component for curing is used for the thermosetting resin, and for the unsaturated polyester resin,
A curing agent (polymerization initiator) such as an organic peroxide or a crosslinking component such as a vinyl monomer is used. In addition, corresponding known components can be used for other thermosetting resins.

For the unsaturated polyester resin, it is preferable to mix various thermoplastic resins and a low-shrinking agent such as a solution thereof in order to prevent shrinkage during curing.

From the viewpoint of moldability and physical properties of the diaphragm, the above-mentioned thermosetting resin is used with respect to 100 parts by weight of organic fibers.
It is preferable to use 250 to 900 parts by weight, and 300 to 4 parts by weight.
It is more preferable to use 00 parts by weight. And when it is within this range, the organic fiber has a volume fiber content of 10 to 4
It is easy to be contained in the range of 0%, and as described in the above-mentioned section of the operation and effect, the physical properties are preferable as the speaker diaphragm.

In addition, other reinforcing materials such as the following pigments, mica, carbon fiber, whiskers, and the like can be used for the speaker diaphragm.

As the pigment, various pigments are used according to various coloring purposes, and a black pigment or the like is mainly used.

As mica, synthetic mica, pearl mica and the like are used. Pearl mica is obtained by chemically depositing titanium dioxide on the surface of mica, and the surface of the diaphragm formed by interference of light has a beautiful blue-green iridescent appearance. Further, the rigidity is larger than that of ordinary mica by coating with titanium dioxide, and the effect of increasing the rigidity of the formed diaphragm is large even with the same addition amount. Regarding the particle size and the amount of mica added, the larger the particle size, the larger the elastic modulus, but if too large, the nonwoven fabric is not uniformly impregnated during molding due to steric hindrance, and the rigidity of each part of the diaphragm is reduced. Significantly different, adversely affecting acoustic characteristics. For example, in the case of the diaphragm of the present invention having a thickness of 0.3 mm, the one having an average particle size of 10 μm and a particle size distribution of 5 to 25 μm is optimal. Although the elastic modulus increases as the amount of addition increases, the nonwoven fabric is not uniformly impregnated during molding due to an increase in weight and steric hindrance. as a result,
In acoustic characteristics, sound pressure drops, energy concentrates on a specific frequency, and the balance is poor. The optimal addition amount is 5μ average particle size
m, mica is almost uniformly dispersed up to 50% by weight.
Considering the decrease in sound pressure, it is 20 ± 5% by weight. The density of pearl mica (ρ = about 3.1) having an average particle diameter of 10 μm is larger than that of mica having the same particle diameter (ρ = about 2.7). The effect of the decrease in sound pressure is large, and the amount of addition is 10 ± 5% by weight.

As the carbon fiber, a PAN-based or pitch-based carbon fiber is used.
Those having a size of μm or less are effective. If it is larger than this, the carbon fibers are not uniformly dispersed in the thin diaphragm, and it is difficult to obtain sufficient physical properties.

As the whiskers, ceramic whiskers such as aluminum borate whiskers are mainly used.
It is effective that the whisker to be added has a fiber length of 10 to 30 μm and a fiber diameter of 0.5 to 1.0 μm or less. If it is larger than this, the particles are not uniformly dispersed in the thin diaphragm, and it is difficult to obtain sufficient physical properties.

The speaker diaphragm of the present invention can be suitably manufactured by the manufacturing method of the present invention. Hereinafter, a method for manufacturing the speaker diaphragm of the present invention will be described.
The production method of the present invention is to apply at least a thermosetting resin composition to a nonwoven fabric that is mechanically bonded by random entanglement of organic fibers, and then impregnate the thermosetting resin composition. It has a step performed in a mold. As the raw materials, the above-mentioned nonwoven fabric, thermosetting resin, and the like are used, and a urethane resin-impregnated PE for an edge portion is further used.
T / PP ultrafine fibers, urethane foam, resin-coated woven fabric, and the like are used.

FIG. 1 schematically shows a process chart of a speaker diaphragm forming process. Hereinafter, an embodiment based on this drawing will be described. In the raw material supply device 1, a nonwoven fabric 1a as a raw material is wound and held in a roll shape.
It is sent out according to the process flow. First, both sides are previously held by the clamp 2 in order to prevent deformation of the raw material during molding. Then, the resin is supplied to the nonwoven fabric 1a from the resin supply nozzle 3a, and the resin is also supplied to the lower mold 4b from the resin supply nozzle 3b. In this state, the resin is pressed by the upper mold 4a, pressurized and heated, and semi-cured (primary molding) of the thermosetting resin is performed. After that, die cutting and outer peripheral cutting are performed, and the speaker diaphragm 5
Is obtained. On the other hand, regarding the edge portion, an edge material 11a as a raw material is held in a roll shape in the raw material supply device 11, and is sent out according to the flow of the process.
First, the edge material 11a is cut into an appropriate length by the cutting blade 12. Then, the lower mold 13b and the upper mold 13a
Then, pressurization and heat molding is performed, and further, die cutting and inner and outer peripheral cutting are performed, and the edge portion 14 is obtained. The speaker diaphragm 5 and the edge portion 14 are set between the lower mold 6b and the upper mold 6a for secondary molding, and the thermosetting resin is completely cured by pressurizing and heating to integrate the two. Is performed. Further, die cutting and center hole cutting are performed, and a product 7 is obtained.

In the above steps, the thermosetting time, the heating temperature and the like are appropriately selected depending on the type of the thermosetting resin, and the press pressure and the press gap are also determined by the physical properties and amount of the thermosetting resin and the nonwoven fabric. It can be adjusted appropriately according to physical properties, density, and the like.

In this embodiment, as an example of the method of applying the resin, the resin is rolled by a mold, but other methods such as spray coating and blade coating can also be applied. In addition, the resin supply is performed in two stages, but this is to prevent the reinforcing material from being biased to one surface, and it is also possible to perform the resin supply in one stage. In the above embodiment, the curing reaction is performed in two stages by the primary molding and the secondary molding. However, if the edge setting is performed first, the curing reaction can be performed in one stage at the same time.

The speaker diaphragm of the present invention can be used for low-, medium-, and high-frequency speakers.
The diaphragm can be formed in a cone shape, a dome shape, a flat plate shape, or the like. When the speaker diaphragm of the present invention uses an organic fiber having a high elastic modulus, the sound speed of a sound wave propagating through the diaphragm is high. .

[0038]

EXAMPLES Examples showing specific structures and effects of the present invention will be described below along with comparative examples and the like, but the present invention is not limited to these examples. In addition, "part" used below
Means "parts by weight" unless otherwise specified.

Example 1 An integrated layer was prepared by randomly orientating short fibers (fiber length: 38 mm) of para-oriented aramid fibers (Teijin Co., Ltd .: Technora, fiber diameter: 1.5 denier) by an air flow by a dry method. Then, a nonwoven fabric having a basis weight of 70 (g / m ² ) was produced by the hydroentanglement method and the needle punch method (Comparative Example). Next, a mixture of the unsaturated polyester solutions prepared in the following proportions was coated at an application density of about 130 to 140 g / m ² . [Blending ratio] Main agent: 100 parts of unsaturated polyester resin (manufactured by Nippon Shokubai Co., Ltd .: G110-AL) Curing agent: 1 part of perbutyl O (Nippon Oil & Fats Co., Ltd.)

Using the same para-oriented aramid fiber as described above, a nonwoven fabric was prepared by a chemical bond method using a PVC emulsion (comparative example) and a thermal bonding method in which 5% by weight of acrylic resin fiber was mixed in para-oriented aramid (comparative example). Was prepared and similarly coated with an unsaturated polyester solution. The basis weight of each of the nonwoven fabrics was 70 (g / m2).
Table 1 shows the results of measuring the strength ratio in the vertical and horizontal directions and the thickness of the sample ² ).

[0041]

[Table 1]

As shown in the results of Table 1, in the chemical bond method and the thermal bond method, the orientation of fibers is apt to occur in the production method, so that the strength ratio between the longitudinal and the lateral directions is large, and pressure bonding is usually performed using a roller. Therefore, the thickness was small, the fiber density was large, and the physical properties were not suitable for the nonwoven fabric of the present invention. Further, there is a disadvantage that an adhesive or a thermoplastic resin is mixed in other than the main fiber. On the other hand, in the needle punch method, the fiber density was appropriate, but the strength ratio between the vertical and horizontal directions was large. On the other hand, in the hydroentanglement method according to the present invention, the strength ratio between the vertical and horizontal directions was close to 1, and the fiber density was also suitable.

The nonwoven fabric coated as described above was sandwiched between a matched die having a diaphragm shape and subjected to pressure and heat molding at 110 ° C. for 2 minutes to obtain a diaphragm. The diaphragm was formed by the above-described steps as shown in FIG. 1 (the same applies to the following examples). The physical properties and moldability of the obtained diaphragm are compared and are shown in Table 2 below. In addition,
The elastic modulus is measured by a viscoelasticity measuring device (VES-HC manufactured by Iwamoto Seisakusho).
(Type).

[0044]

[Table 2] As shown in the results of Table 2, the chemical bond method and the thermal bond method greatly differ in the longitudinal and horizontal elastic moduli due to the influence of the physical properties of the nonwoven fabric. Since the movement was restricted, the moldability was poor such as cracks and wrinkles during molding. In addition, although the formability of the needle punch method is acceptable, the elastic modulus in the vertical and horizontal directions is significantly different, and this affects the elongation of the nonwoven fabric during molding. And other problems. On the other hand, in the hydroentanglement method according to the present invention, the vertical and horizontal elastic moduli were almost equal, and the moldability was good.

Example 2 (Nonwoven fabric of para-oriented aramid fiber alone) Para-oriented aramid fiber + unsaturated polyester resin An unsaturated polyester solution having the following composition was prepared. Unsaturated polyester resin (Nippon Shokubai Co., Ltd .: G110-AL) 100 parts Low shrinkage agent (Nippon Oil & Fats Co., Ltd .: Modepar S501) 3 parts Perbutyl O (Nippon Oil & Fats Co., Ltd.) 1 part Black pigment (SUMI (Kura Color Co., Ltd .: KR8E305) 3 parts

On the other hand, short fibers (fiber length: 38 mm) of para-oriented aramid fiber (Teijin Corp .: Technora, fiber diameter: 1.5 denier) are randomly oriented by an air flow by a dry method to produce an integrated layer. Further, a basis weight of 70 g / m produced by mechanically entangled the fibers by a hydroentanglement method.
No. ² nonwoven fabrics were produced. The non-woven fabric was coated with the prepared unsaturated polyester solution at an application density of about 130 to 140 g / m ² , and the coated non-woven fabric was mixed with a diaphragm-shaped matched die.
The diaphragm of the present invention having a diameter of 16 cm and a thickness of 0.3 mm was obtained by molding at 10 ° C. for 2 minutes.

B. Para-oriented aramid fiber + unsaturated polyester resin + mica An unsaturated polyester solution having the following composition was prepared. 100 parts of unsaturated polyester resin (manufactured by Nippon Shokubai Co., Ltd .: G110-AL) 3 parts Low shrinkage agent (manufactured by NOF Corporation: Modeper S501) 3 parts Synthetic mica (manufactured by Corp Chemical Co., Ltd .: MK-100, average) Particle size 5 μm) 10 parts Perbutyl O (Nippon Oil & Fats Co., Ltd.) 1 part Black pigment (manufactured by Sumika Color Co., Ltd .: KR8E305) 3 parts

On the other hand, short fibers (fiber length: 38 mm) of para-oriented aramid fibers (Teijin Co., Ltd .: Technora, fiber diameter: 1.5 denier) were randomly oriented by an air flow by a dry method to produce an integrated layer. Further, a basis weight of 70 g / m produced by mechanically entangled the fibers by a hydroentanglement method.
No. ² nonwoven fabrics were produced. The non-woven fabric was coated with the prepared unsaturated polyester solution at an application density of about 130 to 140 g / m ² , and the coated non-woven fabric was mixed with a diaphragm-shaped matched die.
The diaphragm of the present invention having a diameter of 16 cm and a thickness of 0.3 mm was obtained by molding at 10 ° C. for 2 minutes.

Comparative Example B The mica was prepared with an average particle size of 18 μm (CLARI, manufactured by Kuraray Co., Ltd.).
A diaphragm was obtained in the same manner as in B, except that TEMICA400W) was replaced by 10 parts. As a result, it was found that the mica to be added had a particle diameter of 10 μm or less and an average particle diameter of about 5 μm was effective. That is, when the particle size is large, mica is poorly dispersed at the time of molding, and the mica hardens only at the center portion of the diaphragm, so that the distortion increases and the peak dip in the high range increases.

C. Para-oriented aramid fiber + unsaturated polyester resin + pearl mica An unsaturated polyester solution having the following composition was prepared. Unsaturated polyester resin (Nippon Shokubai Co., Ltd .: G110-AL) 100 parts Low shrinkage agent (Nippon Oil & Fats Co., Ltd .: Modepar S501) 3 parts Pearl mica (Merck Japan K.K .: Iriodin221, average particle size) 10 μm) 10 parts Perbutyl O (Nippon Oil & Fats Co., Ltd.) 1 part Black pigment (manufactured by Sumika Color Co., Ltd .: KR8E305) 3 parts

On the other hand, short fibers (fiber length 38 mm) of para-oriented aramid fibers (Teijin Corp .: Technora, fiber diameter 1.5 denier) were randomly oriented by an air flow by a dry method to produce an integrated layer. Further, a basis weight of 70 g / m produced by mechanically entangled the fibers by a hydroentanglement method.
No. ² nonwoven fabrics were produced. The non-woven fabric was coated with the prepared unsaturated polyester solution at an application density of about 130 to 140 g / m ² , and the coated non-woven fabric was mixed with a diaphragm-shaped matched die.
The diaphragm of the present invention having a diameter of 16 cm and a thickness of 0.3 mm was obtained by molding at 10 ° C. for 2 minutes. Here, the added pearl mica is obtained by chemically depositing titanium dioxide on the surface of the mica, but the surface of the formed diaphragm has a beautiful blue-green iridescent appearance due to light interference. I understood that. Furthermore, it was found that the rigidity of the formed diaphragm was increased by the titanium dioxide coating and the rigidity was larger than that of ordinary mica.

D. Para-oriented aramid fiber + unsaturated polyester resin + pearl mica / two layers An unsaturated polyester solution (A) similar to the above C and an unsaturated polyester solution having the following composition are prepared (B). Unsaturated polyester resin (Nippon Shokubai Co., Ltd .: G110-AL) 100 parts Low shrinkage agent (Nippon Oil & Fats Co., Ltd .: Modepar S501) 3 parts Pearl mica (Merck Japan K.K .: Iriodin221, average particle size) 10 μm) 10 parts Perbutyl O (Nippon Oil & Fats Co., Ltd.) 1 part

In the same manner as in Example C, the unsaturated polyester solution (A) was added to the para-oriented aramid fiber by about 100 to 110.
g / m ^{2 at} a coating density and molded at 96 ° C. for 1 minute in a matched die having a diaphragm shape of 16 cm in diameter to obtain a 0.28 mm thick semi-cured first diaphragm. Was. Next, mold clearance is 0.30m
The first vibrating plate is placed on the matched die having the same shape with the concave shape facing upward, and about 3 to 5 g of the unsaturated polyester solution (B) is dropped at the center thereof and molded at 110 ° C. for 2 minutes. Thus, a diaphragm of the present invention having a diameter of 16 cm and a thickness of 0.3 mm was obtained. In the configuration of the present embodiment, the pearl mica is oriented in the transparent resin on the first diaphragm serving as the base in the transparent resin so that the plane is more aligned in the thickness direction than in the embodiment C, and is dispersed on the diaphragm surface. The surface of the plate has a beautiful blue-green iridescent appearance. Further, since an oriented layer of pearl mica is formed on the surface, the rigidity is higher, and the effect of increasing the rigidity of the formed diaphragm is increased even with the same amount of addition.

In addition to the above, various experiments were conducted on the particle size and addition amount of mica. The optimum addition amount was almost uniformly dispersed up to 50% by weight in mica having an average particle size of 5 μm, but the sound pressure was reduced. Was considered, it was found to be 20 ± 5% by weight. Further, pearl mica having an average particle size of 10 μm (ρ =
In the case of about 3.1), the density is larger than that of mica having the same particle size (ρ = about 2.7).
± 5% by weight was found to be optimal.

E. Para-oriented aramid fiber + unsaturated polyester resin + carbon fiber An unsaturated polyester solution having the following composition was prepared. 100 parts of unsaturated polyester resin (manufactured by Nippon Shokubai Co., Ltd .: G110-AL) 3 parts Low shrinkage agent (manufactured by Nippon Oil & Fats Co., Ltd .: Modeper S501) 3 parts Carbon fiber (manufactured by Toho Rayon Co., Ltd .: BESFIGHT, HTA-CMF) −0040-E, average fiber length 40 μm) 10 parts Perbutyl O (Nippon Oil & Fats Co., Ltd.) 1 part Black pigment (manufactured by Sumika Color Co., Ltd .: KR8E305) 3 parts

On the other hand, short fibers (fiber length: 38 mm) of para-oriented aramid fiber (Teijin Corp .: Technora, fiber diameter: 1.5 denier) were randomly oriented by an air flow by a dry method to produce an integrated layer. Further, a basis weight of 70 g / m produced by mechanically entangled the fibers by a hydroentanglement method.
No. ² nonwoven fabrics were produced. The non-woven fabric was coated with the prepared unsaturated polyester solution at an application density of about 130 to 140 g / m ² , and the coated non-woven fabric was mixed with a diaphragm-shaped matched die.
The diaphragm of the present invention having a diameter of 16 cm and a thickness of 0.3 mm was obtained by molding at 10 ° C. for 2 minutes.

Comparative Example E A carbon fiber was prepared using an average fiber length of 160 μm (Toho Rayon Co., Ltd.)
Made: BESFIGHT, HTA-CMF-0160-O
H) A diaphragm was obtained in the same manner as in E, except that 10 parts were used. As a result, the carbon fiber to be added has a fiber length of 40
It was found that those having a size of μm or less were effective. That is, if it is larger than this, the carbon fibers are not uniformly dispersed in the thin diaphragm, and sufficient physical properties cannot be obtained.

F. Para-oriented aramid fiber + unsaturated polyester resin + whisker An unsaturated polyester solution having the following composition was prepared. Unsaturated polyester resin (Nippon Shokubai Co., Ltd .: G110-AL) 100 parts Low shrinkage agent (Nippon Oil & Fat Co., Ltd .: Modepar S501) 3 parts Aluminum borate whisker (Shikoku Oil & Fat Co., Ltd .: Arbolex YS1) 10 parts Perbutyl O (Nippon Oil & Fats Co., Ltd.) 1 part Black pigment (manufactured by Sumika Color Co., Ltd .: KR8E305) 3 parts

On the other hand, short fibers (fiber length: 38 mm) of para-oriented aramid fiber (Teijin Corp .: Technora, fiber diameter: 1.5 denier) were randomly oriented by an air flow by a dry method to produce an integrated layer. Further, a basis weight of 70 g / m produced by mechanically entangled the fibers by a hydroentanglement method.
No. ² nonwoven fabrics were produced. The non-woven fabric was coated with the prepared unsaturated polyester solution at an application density of about 130 to 140 g / m ² , and the coated non-woven fabric was mixed with a diaphragm-shaped matched die.
The diaphragm of the present invention having a diameter of 16 cm and a thickness of 0.3 mm was obtained by molding at 10 ° C. for 2 minutes.

G. PPTA fiber woven fabric + epoxy resin (conventional example) A plain woven fabric of PPTA fiber (Toray Dupont: Kevlar, fiber diameter 1000 denier) is impregnated with epoxy resin so that the resin ratio becomes about 45% by weight. The prepared prepreg is heated at 120 ° C. using a matched die having a diaphragm shape.
By molding for 12 minutes at a diameter of 16 cm and a thickness of 0.1 cm.
A 3 mm diaphragm was obtained.

With respect to the speaker diaphragm obtained as described above, the following tests were conducted for Young's modulus, density, specific elastic modulus, and internal loss. Table 3 shows the results. Young's modulus: Viscoelasticity measurement device (VES-H manufactured by Iwamoto Seisakusho)
C type). Density: Measured according to JIS C2111. Specific modulus: Calculated from Young's modulus and density. Internal loss: Viscoelasticity measurement device (VES-H manufactured by Iwamoto Seisakusho)
C type).

[0062]

[Table 3]

As shown in the results of Table 3, it was found that all of the products of the present invention exhibited suitable physical properties as a speaker diaphragm. In the conventional example G, the physical properties are within an allowable range.
Due to the use of plain weave, large changes in physical properties due to the direction of weaving, the filler is difficult to disperse evenly in the resin due to steric hindrance of the weave, and misalignment occurs during molding, and there is no fiber in the molded product There were problems such as the occurrence of parts.

Example 3 (Example of nonwoven fabric in which PP fiber is mixed with para-oriented aramid fiber) A An unsaturated polyester solution having the following composition was prepared. Unsaturated polyester resin (Nippon Shokubai Co., Ltd .: G110-AL) 100 parts Low shrinkage agent (Nippon Oil & Fats Co., Ltd .: Modepar S501) 3 parts Perbutyl O (Nippon Oil & Fats Co., Ltd.) 1 part Black pigment (SUMI (Kura Color Co., Ltd .: KR8E305) 3 parts

On the other hand, a short fiber (fiber length: 38 mm) of para-oriented aramid fiber (Teijin Co., Ltd .: Technora, fiber diameter: 1.5 denier) was mixed with 10 wt% of polypropylene fiber short fiber (fiber length: 30 mm) and dried by dry mixing. The fibers are randomly oriented by an air flow according to a method to produce an integrated layer, and the fibers are mechanically entangled with each other by a water entanglement method.
g / m ² nonwoven fabric was produced. The unsaturated polyester solution prepared on the nonwoven fabric is coated at an application density of about 130 to 140 g / m ² , and molded at 110 ° C. for 2 minutes in a matched die having a diaphragm to obtain a diameter of 16 c.
m, a diaphragm of the present invention having a thickness of 0.3 mm was obtained.

On the other hand, in Comparative Example B, a mixture obtained by mixing 20% by weight of polypropylene fiber short fibers was used.
A non-woven fabric was prepared in the same manner as in A above, using 0% by weight and 40% by weight in Comparative Example D, and a diaphragm was prepared.

Conventional Example E (Conventional example of nonwoven fabric in which PP fiber is mixed with PPTA fiber) Short fiber of PPTA fiber (Toray Dupont Co., Ltd .: Kevlar, fiber diameter: 1000 denier) (short fiber of 38 mm) and short fiber of polypropylene fiber (Fiber length: 30 mm) was mixed at 10% by weight, and a diaphragm was produced in the same manner as in A above.

The speaker diaphragm obtained above was tested for Young's modulus, density, specific elastic modulus, and internal loss in the same manner as described above. Table 4 shows the results.

[0069]

[Table 4] As shown in the results of Table 4, when the amount of the polypropylene fiber added to the para-oriented aramid fiber exceeds 30% by weight, the Young's modulus is greatly reduced.

Example 4 An unsaturated polyester solution having the following composition was prepared. Unsaturated polyester resin (Nippon Shokubai Co., Ltd .: G110-AL) 100 parts Low shrinkage agent (Nippon Oil & Fats Co., Ltd .: Modepar S501) 3 parts Perbutyl O (Nippon Oil & Fats Co., Ltd.) 1 part Black pigment (SUMI (Kura Color Co., Ltd .: KR8E305) 3 parts

On the other hand, short fibers (fiber length: 38 mm) of para-oriented aramid fiber (Teijin Corp .: Technora, fiber diameter: 1.5 denier) were randomly oriented by an air flow by a dry method to produce an integrated layer. Further, a basis weight of 10 g / m produced by mechanically entangled the fibers by a hydroentanglement method.
^{From 2,} a nonwoven fabric having a basis weight of 100 g / m ² was produced. Approximately 130-14
By coating at a coating density of 0 g / m ² and molding at 110 ° C. for 2 minutes in a cone-shaped diaphragm-shaped matched die (diameter: 16 cm, mold clearance: 0.3 mm), diaphragms with different fiber contents are obtained. Was. FIG. 2 shows the relationship between the Young's modulus of the obtained diaphragm (the measuring method is the same as described above) and the volume fiber content. The numbers in the figure indicate the weighed values. As shown in the results of FIG. 2, when the organic fiber is contained in the range of the volume fiber content of 10 to 40%, the Young's modulus becomes larger at the boundary of the range and inside the range limit. Conversely, outside the range limit, the Young's modulus is greatly reduced, resulting in undesirable physical properties as a speaker diaphragm. As shown in FIG. 2, when the volume fiber content exceeds a certain value, the Young's modulus of the diaphragm decreases because the degree of freedom in the structure of the nonwoven fabric is large, and the organic fibers are fully stretched after molding. Not indicate.

[Brief description of the drawings]

FIG. 1 is a diagram schematically showing a process diagram of a forming process of a speaker diaphragm.

FIG. 2 is a diagram showing the relationship between the Young's modulus and the volume fiber content of the diaphragm obtained in Example 4.

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁷ Identification code FI B29K 105: 08 B29L 31:38 B29L 31:38 B29C 67/14 L (72) Inventor Yuji Ono 2nd Nisshinmachi, Neyagawa-shi, Osaka No. 1 Onkyo Corporation (56) References JP-A-56-21499 (JP, A) JP-A-63-215291 (JP, A) JP-A-3-193958 (JP, A) JP-A-7- 145543 (JP, A) JP-A-8-340593 (JP, A)

Claims (3)

(57) [Claims] 1. A speaker diaphragm in which a non-woven fabric is formed and cured by impregnating at least a thermosetting resin, wherein the non-woven fabric is manufactured by a fluid entanglement method, and mainly includes a high elastic modulus organic fiber. Organic fibers are entangled randomly
A speaker diaphragm that is mechanically coupled . 2. The organic fiber has a volume content of 10 to 40%.
The speaker diaphragm according to claim 1, wherein the speaker diaphragm is contained within the range of. 3. An organic fiber which is produced by a fluid entanglement method and is mainly entangled with organic fibers mainly composed of organic fibers having a high elastic modulus.
A method for manufacturing a speaker diaphragm, comprising a step of applying and impregnating at least a thermosetting resin to a mechanically bonded nonwoven fabric, and performing thermosetting of the thermosetting resin composition in a mold.