JPH034698A - Acoustic vibrator and its manufacture - Google Patents

Abstract

PURPOSE:To obtain a light vibrator having high elasticity by giving the specified range weight % of a polyolefin polymer, the specific weight % of mica having the weight average flake diameter of a specific range and a weight average aspect ratio more than a specific value, and the specific weight % of aluminum flake having the weight average flake diameter of the specific range. CONSTITUTION:An acoustic vibrator consists of 50-90weight% of polyolefin group polymer, 9.5-49.5weight% of mica having the weight mean flake diameter of 5-30mum and the weight mean aspect rate of more than '5', and 0.5-5weight% of Al flake having the weight mean flake diameter of 5-30mum. The polyolefin group polymer, mica and the Al flake are melted and mixed. A sheet material is formed from an obtained composite material and it is shaped into an arbitral form. Thus, the light acoustic vibrator which has high elasticity, high internal loss and the luster of color metal is supplied.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an acoustic vibrator represented by a speaker cone, etc., and a method for manufacturing the same.

[Conventional technology]

Traditionally, paper and metal are used as acoustic vibrator materials,
In particular, metal foils such as berylum and aluminum are used as the material for the high-pitched speaker vibrator. recently,
Polyolefin polymers are used as acoustic vibrator materials (Japanese Patent Laid-Open Nos. 52-145024 and 1983).
(See Japanese Patent Publication No. 3-45226 and Japanese Patent Publication No. 55-46112).

In addition, as an acoustic vibrating body with a high elastic modulus, a vibrating body is made of thermoplastic resin and flaky graphite, and a moving body made of thermosetting resin and mica is manufactured using a paper machine by mixing carbon fiber and mica. A diaphragm has been reported (
Special Publication No. 58-53560, Special Publication No. 54-2725
Publication No. 0, JP-A-57-154994, JP-A-1@
58-3499 and JP-A-52-75316).

[Problem to be solved by the invention]

Acoustic vibrators made of paper have the advantage of being lightweight and have a large internal loss, but the problem is that the sound changes depending on humidity and the specific modulus of elasticity is low, while vibrators made of metal or metal foil have a high internal loss. The problem is that it is low. However, like vibrating bodies made of paper, vibrating bodies made of polyolefin polymers have a problem of low elastic modulus. Vibrating bodies made of mica and diaphragms made from a mixture of carbon fiber and mica using a paper machine both have a problem of high density and lack of design qualities such as hue and surface gloss.

The object of the 9-acoustic diaphragm, which is given a design by painting, vapor deposition, plating, etc., is to provide an acoustic diaphragm that has an internal loss that easily causes the coating film to come off, and has a colored metallic luster. Another object of the present invention is to provide an economically advantageous method of manufacturing an acoustic vibrator.

[Means to solve the problem]

According to the present invention, the above object is achieved by: (i) polyolefin polymer 50-90% by weight (O) mica having a weight-average flake diameter of 5-30 μm and a weight-average aspect ratio of 5 or more; 49.5% by weight and 0→5-3
Aluminum flakes 0 with weight average flake diameter of 0 μm
．． This is achieved by providing an acoustic vibrating body (hereinafter sometimes referred to as a vibrating body) consisting of 5 to 5% by weight, and is also obtained by melt-mixing the above polyolefin polymer, mica, and aluminum flakes. This is achieved by providing a method for manufacturing the acoustic vibrator as described above, which comprises forming a sheet-like material from a composite material and then molding it into an arbitrary shape.

Polyolefin polymers used in the present invention include polyethylene (especially high-density polyethylene), polypropylene (especially isotactic polyglopylene),
Polybutene, poly3-methylpentene-1, bo! j 4
−． Examples include polymers of aliphatic olefins such as 1'tilpentene-1, and copolymers whose main components are constituent monomers of these polymers. Other seven polymers constituting the copolymer
As the main monomer is different from other olefin monomers, vinyl acetate, maleic anhydride, acrylic acid.

Examples include methyl acrylate, methacrylic acid, and methyl methacrylate, and these copolymer monomers are used within a range that does not inhibit the crystallinity of the polyolefin polymer. The copolymer may be not only a random copolymer but also a block or graft copolymer. Polyolefins modified with maleic anhydride, acrylic acid, methacrylic acid, etc. have good adhesion to mica and aluminum flakes. In the present invention, among the above-mentioned polymers, it is preferable to use an isotactic polypropylene polymer which has good moldability and provides a vibrating body with excellent heat resistance.

In the present invention, the blending amount of the polyolefin polymer is 50
If it is less than % by weight, the moldability of the resulting vibrating body may be poor.
), 90 again! If the amount exceeds -, the elastic modulus of the obtained moving body decreases. The blending amount of polyolefin polymer is 5
It is preferably in the range of 5 to 85% by weight.

Examples of mica used in the present invention include various types of mica such as white mica (muscovite), gold mica (phlogovite), and synthetic mica. The weight average flake diameter of mica is 5 to 30 μm, preferably 7 to 25 μm.
m aashi,! The overall average aspect ratio is 5 or more, preferably 7 or more. The weight average flake diameter is determined by classifying mica using a microseep and using the
Using the Mler diagram, it corresponds to the opening of the micro-sheep through which 50 tons of the total weight of mica passes, and the weight-average aspect ratio is the weight-average thickness of mica obtained by determining the weight-average flake diameter by the water surface single particle removal method. This is the value obtained by dividing the

When the weight average flake diameter is less than 5 μm, the elastic modulus and specific elastic modulus of the obtained vibrating body are low, and when it exceeds 30 μm, the surface of the obtained @ moving body becomes rough and the surface gloss is poor.

Furthermore, when the weight average aspect ratio is less than 5, the effect of improving the elastic modulus and specific elastic modulus of the vibrating body obtained is poor. If the mica content in the acoustic vibrating body is less than 9.5% by weight, the resulting vibrating body will not have sufficient elastic modulus and specific elastic modulus;
．． When the amount exceeds 5% by weight, the density of the composite material increases, and melt mixing is often extremely difficult. The preferred amount of mica is in the range of 15 to 40 tft%.

The aluminum flakes used in the present invention include those made by crushing aluminum foil into flakes. The weight average flake diameter of aluminum flakes is 5~
30 μm, preferably 8 to 25 μm. When the weight average flake diameter of the aluminum flakes is less than 5AIrrL, there is no effect of improving the elastic modulus and specific elastic modulus of the obtained vibrating body, and when it exceeds 30 μm, the surface of the obtained vibrating body becomes rough and the surface gloss is poor. The internal loss decreases as well. The weighted average aspect ratio of the aluminum flakes is not particularly limited, but preferably 5 or more gives preferable results. Further, when the amount of aluminum flakes in the vibrating body is less than 0.5% by weight, the vibrating body obtained does not have a colored metallic luster.

If it exceeds 5% by weight, the elastic modulus, specific elastic modulus and internal loss of the vibrating body will decrease.

In manufacturing the vibrating body in the present invention, fillers other than mica and aluminum flakes are added to the polyolefin polymer,
For example, vibrating talc, calcium carbonate, wollastonite, glass peas, magnesium hydroxide, silica, graphite, glass flakes, barium sulfate, aluminum, potassium titanate, glass fiber, carbon fiber, vinyl fiber, etc. It can be added within a range that does not impair body performance.

Additives for improving the interfacial adhesion of mica and alkali flakes, such as an ift syncoupling agent, pigments, plasticizers, stabilizers, lubricants, flame retardants, etc. may be added as necessary.

As a method for molding the vibrating body of the present invention, for example, a vacuum molding method, a pressure molding method, etc. are employed. Although the thickness of the vibrating body is not particularly limited, it is preferably in the range of 100 to 1000 can.

The acoustic effect of an acoustic vibrator is generally expressed by specific modulus of elasticity and internal loss. The square root of the specific elastic modulus represents the speed of sound propagating within the molded product, and the higher the specific elastic modulus, the lower the frequency of resonance. In other words, internal loss represents a measure that blunts the degree of resonance, and the higher this value, the lower the degree of resonance. Therefore,
A diaphragm with a high specific modulus of elasticity and a high internal loss has a low degree of resonance and is excellent as an acoustic vibrator.

The vibrating body of the present invention not only has a high specific modulus of elasticity and a high internal loss, but also has an excellent design, especially a colored metallic luster.

〔Example〕

EXAMPLES Hereinafter, the present invention will be specifically explained with reference to Examples, but the present invention is not limited to these Examples in any way. In addition, each physical property of the vibrating body was determined by measurement using the method shown below.

Density (ρ): JIS K7112 using ethanol
It was measured and determined in accordance with Method A.

Dynamic modulus of elasticity (E') and internal loss (tan δ): The values were determined using a Vibron (DDV-2, manufactured by Toyo Boldline Co., Ltd.) at a frequency of 110H1 and 20°C.

Glossiness: In accordance with JIS Z 8741, values were measured at an incident angle and a reflection angle of 60 degrees using a digital variable angle gloss meter (UGV-50, Suga Test Instruments ■!1).

Surface roughness [center line average roughness, diameter [μm]: JIS B
0601, using a surface roughness meter (SE-4, manufactured by Koita Institute).

Example 1 4511 tk% of white mica with a weight average flake diameter of 7 μm and a weight average aspect ratio of 7, 0.7 wt. % of aluminum flakes (manufactured by Daiwa Metal Industries) with a weight average flake diameter of 8 μm, and crystalline polypropylene (B-101H1) (manufactured by Ube Industries)
54.3% by weight was melt-mixed at 230°C using a twin-screw extruder, and the resulting pellet was melt-mixed using a twin-screw extruder again at 220°C.
It was extruded into a sheet at 0°C to obtain a sheet with a thickness of 400 μm. Next, the obtained sheet was vacuum-formed into a speaker cone shape to obtain a vibrating body. A test piece was cut out from this vibrator and its physical properties were measured and shown in Table 1.

The performance of the obtained vibrating body exceeds that of a vibrating body made of paper or aluminum, and the glossiness is as high as that of a vibrating body made of aluminum.

Examples 2 and 3 As the white mica and aluminum flakes in Example 1, white mica having a weight average flake diameter of 15 μm and a weight average aspect ratio of 14 was used as a white mica having a weight average flake diameter of 15 μm and a weight average aspect ratio of 14. 5x*S distribution (Example 2), t or weight average flake diameter 28p1
12% by weight of white mica with a weight average aspect ratio of 25 and 2% of aluminum flakes with a weight average flake diameter of 25/Jn.
The pellets were obtained in the same manner as in Example 3, except that they were blended in a weight percent manner, and a vibrating body was obtained in the same manner as in Example 1 using these pellets. Test pieces were cut out from these vibrators and their physical properties were measured and shown in Table 1.

Example 4 In Example 2, 4% by weight of aluminum flakes was blended, and propylene-ethylene block copolymer (B-60LH) was used instead of crystalline polypropylene.

Ube Industries ■! ! A pellet was obtained in the same manner except that 66% by weight was added, and a vibrating body was obtained using the pellet in the same manner as in Example 1. A test piece was cut out from this vibrating body, and its physical properties were measured and shown in Table 1.

Example 5 A sheet-like product with a thickness of 400 μm was obtained using the same composition and method as in Example 1. Then, the obtained sheet was subjected to a pressure of 5 kf/
- Obtain a speaker cone-shaped vibrating body by air forming. A test piece was cut out from this vibrating body, and its physical properties were measured and shown in Table 1.

Comparative Examples 1 and 2 In Example 1, white mica having a gL average flake diameter of 3-1 and a weight average aspect ratio of 3 was used (
Comparative Example 1) Or pellets were obtained in the same manner except that the content of white mica was 55% by weight (Comparative Example 2), and using these pellets, a vibrating body was obtained in the same manner as in Example 1. Ta. Test pieces were cut out from these vibrators and their physical properties were measured and shown in Table 1.

The vibrating body obtained in Comparative Example 1 was inferior in elastic modulus and specific elastic modulus compared to the vibrating bodies obtained in Examples 1 to 5, and the vibrating body obtained in Comparative Example 2 had a lower mica content. Since the gloss level of the vibrating body is low due to the high gloss level, the surface of the vibrating body may be different from Examples 1 to 4.
It was rough compared to the vibrating body obtained in .

Comparative Examples 3 and 4 In Example 1, the weight average flake diameter was 3 as white mica.
5 μm 1 white mica with a weight average aspect ratio of 28
3% by weight (Comparative Example 3), t7'h has a weight average flake diameter of 28μ as white mica and aluminum flakes.
m1 13 weights of white mica with a weight average aspect ratio of 25 tlI1 Bullets were obtained in the same manner except that 2% by weight of aluminum flakes with a weight average flake diameter of 35 μm were used (Comparative Example 4), and these pellets were used to produce Example 1. Obtain the vibrating body in the same manner as in . Test pieces were cut out from these vibrators and their physical properties were measured and shown in Table 1.

Compared to the vibrating bodies obtained in Examples 1 to 5, these vibrating bodies had rough surfaces, lowered gloss, and were inferior in design.

Comparative Example 5 A pellet was obtained in the same manner as in Example 4 except that the content of aluminum flakes was 7% by weight, and a vibrating body was obtained in the same manner as in Example 1 using this pellet. A test piece was cut out from this vibrator and its physical properties were measured and shown in Table 1.

This vibrating body is compared to the vibrating bodies obtained in Examples 1 to 5,
The elastic modulus, specific modulus and internal loss were poor.

Comparative Example 6 A pellet was obtained in the same manner as in Example 2 except that the weight average flake diameter of the aluminum flakes was 3 μm, and a vibrating body was obtained using this pellet in the same manner as in Example 2. A test piece was cut out from this vibrating body, and its physical properties were measured and shown in Table 1.

This vibrating body is compared to the vibrating bodies obtained in Examples 1 to 5,
The specific elastic modulus was poor.

Comparative Example 7 Pellets were obtained in the same manner as in Example 1 except that aluminum flakes were not added, and these pellets were used to prepare Example 1.
A vibrating body was obtained in the same manner as in . A test piece was cut out from this vibrating body and its physical properties were measured as shown in Table 1.

This vibrating body is compared to the vibrating bodies obtained in Examples 1 to 5,
Internal loss and gloss were poor.

Comparative Example 8 A vibrating body was made in the same manner as in Example 1 using a commercially available crystalline polypropylene sheet with a thickness of 400 μm.

A test piece was cut out from this vibrating body and its physical properties were measured.Table I
K showed. This vibrating body had a specific elastic modulus inferior to that of the vibrating bodies obtained in Examples 1 to 5.

Comparative Examples 9 and 10 Table 1 shows the physical properties of the vibrating body made of aluminum foil (Comparative Example 8) and the vibrating body made of paper (Comparative Example 9). The vibrating body made of aluminum foil was inferior in internal loss compared to the vibrating bodies obtained in Examples 1 to 5, and the vibrating body made of paper was inferior in elastic modulus, specific elastic modulus, and gloss.

Bottom margin of work [Effects of the invention] The present invention provides an acoustic vibrator that is lightweight, has a high elastic modulus, a high internal loss, and has a colored metallic luster. Further, according to the method of the present invention, an acoustic vibrator can be manufactured economically.

Tokusuki Dekaojin RiRashi Co., Ltd.

Claims (1)

[Scope of Claims] 1. (a) 50 to 90% by weight of a polyolefin polymer; (b) mica having a weight average flake diameter of 5 to 30 μm and a weight average aspect ratio of 5 or more; 9.5 to 49.
and (c) 0.5 to 5 weight % of aluminum flakes having a weight average flake diameter of 5 to 30 μm. 2. (a) 50 to 90% by weight of a polyolefin polymer; (b) mica having a weight average flake diameter of 5 to 30 μm and a weight average aspect ratio of 5 or more; 9.5 to 49.
5% by weight and (c) 0.5 to 5% by weight of aluminum flakes having a weight average flake diameter of 5 to 30 μm are melt-mixed, a sheet-like material is formed from the obtained composite material, and then the sheet-like material is 2. The method of manufacturing an acoustic vibrator according to claim 1, wherein the acoustic vibrator is formed into an arbitrary shape.