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JP2001157295

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This translation is machine-generated. It cannot be guaranteed that it is intelligible, accurate,
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DESCRIPTION JP2001157295
[0001]
TECHNICAL FIELD The present invention relates to a member for a speaker. More particularly,
the present invention relates to an inexpensive and lightweight speaker member having high
internal loss and high elasticity and high strength.
[0002]
2. Description of the Related Art Conventionally, various materials have been used as materials
for forming a speaker member. In particular, metal foils and polymer films are suitably used as
the material for forming the dome-shaped diaphragm.
[0003]
A diaphragm made of metal foil (e.g. aluminum, titanium) is of high strength and as a result has
excellent fh. However, metal foils are heavy and have low internal losses.
[0004]
As the polymer film, engineering plastics such as polyether imide (PEI) and polyether ether
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ketone (PEEK) are suitably used. Engineering plastics have increased strength compared to
general purpose plastics, but at the same time, they become heavier and lower internal losses. As
the weight increases, the specific modulus decreases, so that only insufficient fh can be obtained.
The reduction of the internal loss leads to harmonic distortion in the middle and high
frequencies. In addition, engineering plastics are more expensive than general purpose plastics.
[0005]
As described above, there is a strong demand for a lightweight and inexpensive speaker member
having high internal loss and high elasticity and high strength.
[0006]
SUMMARY OF THE INVENTION The present invention has been made to solve the abovementioned conventional problems, and the object of the present invention is to provide high
elasticity and high strength while having a large internal loss and a light weight. An object of the
present invention is to provide an inexpensive speaker member.
[0007]
[Means for Solving the Problems] The speaker member of the present invention is formed from a
resin composition containing a syndiotactic olefin polymer having a Mw / Mn of 4 or less or a
syndiotactic styrene polymer as a main agent. And the paint is applied to the surface.
In a preferred embodiment, the syndiotactic olefin-based polymer or syndiotactic styrenic
polymer is a polymer obtained by a polymerization reaction using a metallocene-based catalyst.
In a preferred embodiment, the metallocene catalyst contains zirconocene and
methylaluminoxane. In a preferred embodiment, the paint is selected from emulsion paint, water
soluble paint, alkyd resin paint, amino alkyd resin paint, epoxy resin paint, polyurethane resin
paint, and acrylic resin paint. According to another aspect of the present invention, a method of
manufacturing a speaker member is provided. This production method comprises the steps of
film-forming a resin composition containing a syndiotactic olefin polymer having a Mw / Mn of 4
or less or a syndiotactic styrene polymer as a main agent, and subjecting the film to corona
discharge treatment The method includes the steps of applying, applying the paint to the corona
discharge treated film, and heat pressing the film applied with the paint.
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[0008]
BEST MODE FOR CARRYING OUT THE INVENTION The speaker member of the present invention
is formed from a resin composition containing a syndiotactic olefin polymer or a syndiotactic
styrene polymer as a main component. Here, "containing as a main ingredient" means that it is
contained in a proportion of 50% by weight or more in the composition. Thus, the term "resin
composition" also encompasses polymers alone.
[0009]
In the present invention, syndiotactic polymer refers to a polymer having a syndiotactic
structure. The syndiotactic structure refers to a structure in which substituents (for example, a
phenyl group in the case of polystyrene) are alternately arranged with respect to a main chain
composed of C̶C bonds. Preferably, the syndiotactic polymer used in the present invention has
a tacticity of 30% or more by 13 C-NMR.
[0010]
As an olefin polymer having such syndiotactic structure, typically, polypropylene,
polyisobutylene and polyamylene can be mentioned. Polypropylene is preferred in terms of
versatility and the excellent properties (for example, light weight, internal loss) of the resulting
speaker member. Styrene-based polymers include polystyrene, polymethylstyrene and
polyethylstyrene. Polystyrene is preferable in that it is excellent in versatility and the
characteristics (for example, light weight) of the obtained speaker member.
[0011]
The syndiotactic polymer used in the present invention has a Mw / Mn of 4 or less, preferably 3
or less, more preferably 2 to 2.5 (a lower limit of the Mw / Mn). Is inevitably 1). When Mw / Mn
is larger than 4, the flowability at the time of molding is often insufficient, and as a result, the
rigidity, heat resistance, chemical resistance, etc. of the resulting speaker member may be
insufficient. There are many.
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[0012]
The degree of polymerization of the syndiotactic polymer is preferably 10 to 100,000, more
preferably 100 to 10,000, and particularly preferably 500 to 5,000. By having the
polymerization degree in such a range, a speaker member having excellent molding fluidity and
dimensional stability can be obtained.
[0013]
The polymerization method of the syndiotactic polymer is not particularly limited, and any
appropriate method may be employed. Preferably, the syndiotactic polymer is polymerized using
a metallocene based catalyst. This is because the resulting polymer has high tacticity, and as a
result, a speaker member having excellent rigidity and internal loss can be obtained.
[0014]
The metallocene catalyst is represented by the following chemical formula:
[0016]
Here, M is a Group 4 transition metal, preferably zirconium or titanium, and more preferably
zirconium.
Each X is independently a halogen, preferably each independently bromine or chlorine. More
preferably, the metallocene catalyst contains methylaminoxan represented by the following
chemical formula as a cocatalyst:
[0018]
Here, n is an integer of 5 to 20. A metallocene based catalyst containing zirconocene as the main
component (eg, 80% by weight) and methylaminoxan as the cocatalyst (eg, 20% by weight) is
particularly preferred for synthesizing the polymer used in the present invention.
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[0019]
The resin composition used in the present invention may contain, in addition to the above
syndiotactic polymer, any suitable component (eg, a reinforcing agent, a colorant). The resin
composition used in the present invention is typically in the form of pellets.
[0020]
Further, in the speaker member of the present invention, the paint is applied to the surface. The
paint may be an emulsion paint, a water-soluble paint or a solvent-based paint (however, in the
case of a solvent-based paint, an aromatic solvent is removed). Because it may swell). Typically,
solvent-based paints are used. Examples of such solvent-based paints include alkyd resin paints,
amino alkyd resin paints, epoxy resin paints, polyurethane resin paints, and acrylic resin paints.
Coatings formed from these paints have properties (eg, strength, internal loss) different from
those of films formed from the above resin composition. As a result, according to the diaphragm
formed of the film to which the paint is applied, friction is generated between the coating film
and the film upon vibration, so the internal loss becomes large. Particularly preferred paints
include acrylic resin paints and epoxy resin paints. The paint usually contains a binder resin, a
crosslinking agent, a solvent and a colorant. For example, as binder resins for acrylic resin
coatings, poly (2-hydroxyethyl methacrylate), poly (2-hydroxyethyl acrylate), polyacrylic acid,
polymethacrylic acid, poly (glycidyl methacrylate), poly (methylolated acrylamide) It can be
mentioned. Examples of the crosslinking agent include etherified urea resins, melamine resins,
amino resins such as benzoguanamine resins, and organic polyamines. The colorant typically
includes a pigment (eg, carbon black).
[0021]
Hereinafter, a preferable example of the manufacturing method of the member for speakers of
this invention is demonstrated. First, the resin composition is formed into a film by any
appropriate method (for example, extrusion). Typically, the thickness of the film is 50 to 75 μm.
Next, the surface of the obtained film is subjected to a corona discharge treatment. The adhesion
to the paint can be improved by applying a corona charge treatment. Next, the paint is applied to
the film subjected to the corona discharge treatment. The method of application and drying is not
particularly limited, and any appropriate method may be employed. The thickness of the coating
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after drying is preferably 4 to 30%, more preferably 6 to 15%, with respect to the thickness of
the resin composition film. By having such a relationship between the thickness of the resin
composition film and the thickness of the coating film, the coating film strength and the adhesion
between the coating film and the film are significantly improved, and as a result, very excellent
internal loss and ratio A speaker member having an elastic modulus is obtained. Finally, the
member for a speaker of the present invention is obtained by heat-pressing the film on which the
coating film is formed. Any appropriate condition may be adopted as the hot press molding
conditions depending on the purpose.
[0022]
Hereinafter, the operation of the present invention will be described. According to the present
invention, there is provided a speaker member using a resin composition containing a
syndiotactic olefin polymer or a styrene polymer having Mw / Mn of 4 or less. Syndiotactic
polymers are very crystalline. In addition, the fluidity at the time of molding is significantly
improved due to having such a very sharp molecular weight distribution. Therefore, shrinkage
due to crystallization of the resulting molded article can be significantly suppressed. As a result,
the speaker member of the present invention is highly elastic and rigid (thus, excellent in
acoustic characteristics), and excellent in moldability and dimensional stability against heat and
humidity. The Mw / Mn of the general-purpose polymer is 6 or more, and the speaker member
obtained by using the general-purpose polymer has elasticity, rigidity, moldability, heat, and
humidity as compared with the speaker member of the present invention. It has been practically
confirmed that any of the dimensional stability is significantly inferior. The effect obtained with
such a polymer with a very sharp molecular weight distribution is unexpectedly good.
[0023]
Further, in the speaker member of the present invention, the paint is applied to the surface. The
coating film formed from the paint has properties (eg, strength, internal loss) different from
those of the film formed from the above resin composition. As a result, according to the member
for a speaker of the present invention, which is formed of a film to which a paint is applied,
friction is generated between the coating and the film upon vibration, so the internal loss
becomes large. Therefore, the member for speakers of the present invention is excellent in
acoustic characteristics. Moreover, as described above, since the resin composition film has a
very small shrinkage at the time of molding, the problem of curling due to the difference in the
shrinkage between the film and the coating does not occur.
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[0024]
In a preferred embodiment, the syndiotactic polymer is obtained by a polymerization reaction
using a metallocene catalyst. By using a metallocene-based catalyst, a syndiotactic polymer
having very high stereoregularity can be obtained, so that elasticity, rigidity, moldability, and
dimensional stability to heat and humidity can be further improved. In addition, it was actually
confirmed that a speaker member having excellent chemical resistance and electrical properties
could be obtained.
[0025]
EXAMPLES The present invention will be specifically described by way of the following examples,
but the present invention is not limited to these examples. In the Examples and Comparative
Examples, parts and percentages are by weight unless otherwise indicated.
[0026]
Example 1 A syndiotactic polystyrene (SPS) resin (pellet-like) polymerized using a metallocene
catalyst was formed into a film having a thickness of 50 μm under the following extrusion
molding conditions. Cylinder temperature Front 290 (° C) Middle part 280 (° C) Rear 270 (°
C) Nozzle 290 (° C) Mold temperature 140-150 (° C) Cooling time 90 (sec) Extrusion pressure
500-1200 ( kgf / cm2)
[0027]
After corona discharge treatment was applied to the obtained film surface, an acrylic resin paint
of the following formulation was applied and dried under the following conditions to form a
coating film. (Formulation of paint) 2-hydroxyethyl methacrylate 100 (parts) amino resin
(crosslinking agent) 5 carbon black 1 (coating conditions) treatment speed 20 (m / min) drying
temperature 130 to 150 (° C.) coating film thickness 5 to 5 7 (μm) The film on which the
coating film is formed is heat-pressed using a mold having a predetermined shape, at a molding
temperature of 160 to 170 ° C, for a molding time of 3 to 5 seconds, and a diaphragm of 25φ
for dome shape speaker I got
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[0028]
The density ρ, Young's modulus (elastic modulus) E, specific elastic modulus E / ρ, and internal
loss of the obtained diaphragm were examined in a conventional manner. The results are shown
in Table 1 below together with the results of Example 2 and Comparative Examples 1 to 3
described later. Furthermore, the frequency characteristics of this diaphragm were examined at
an on-axis 50 cm of the diaphragm and an output of 1 W. The results are shown in FIG.
[0030]
EXAMPLE 2 A diaphragm was produced in the same manner as in Example 1 except that an
epoxy resin paint of the following formulation was applied and dried under the following
conditions to form a coating film. (Formulation of paint) Epoxy resin 100 (parts) Organic
polyamine (crosslinking agent) 5 Carbon black 1 (coating conditions) Treatment speed 20 (m /
min) Drying temperature 40-80 (° C) Coating film thickness 5-7 (μm The obtained diaphragm
was subjected to the same evaluation as in Example 1. The results are shown in Table 1 above.
[0031]
Comparative Example 1 A film having a thickness of 50 μm was formed using polyether imide
(PEI) (manufactured by Mitsubishi Resins Co., Ltd., Speria UT), and this film had a molding
temperature of 200 to 220 ° C. and a molding time of 5 seconds. The resultant was heatpressed in the following manner to prepare a diaphragm for a dome-shaped speaker of 25φ. The
obtained diaphragm was subjected to the same evaluation as in Example 1. The results are shown
in Table 1 above.
[0032]
Comparative Example 2 A film of 50 μm in thickness was formed using polyetheretherketone
(PEEK) (VICTREX, manufactured by Victrex MC Co., Ltd.), and this film was molded at a
temperature of 240 to 260 ° C. and a molding time of 3 to 5 It heat-press-molded on the
conditions of second, and produced the diaphragm for dome shape speakers of 25 (phi). The
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obtained diaphragm was subjected to the same evaluation as in Example 1. The results are shown
in Table 1 above. Furthermore, the frequency characteristics of this diaphragm were examined at
an on-axis 50 cm of the diaphragm and an output of 1 W. The results are shown in FIG.
[0033]
(Comparative Example 3) A dome of 25φ was prepared in the same manner as Example 1,
except that the paint was not applied, and the heat press molding was performed under the
conditions of a molding temperature of 150 to 160 ° C. and a molding time of 3 to 5 seconds.
Type diaphragm for speaker was produced. The obtained diaphragm was subjected to the same
evaluation as in Example 1. The results are shown in Table 1 above. Furthermore, the frequency
characteristics of this diaphragm were examined at an on-axis 50 cm of the diaphragm and an
output of 1 W. The results are shown in FIG.
[0034]
As apparent from Table 1, the diaphragms of Examples 1 and 2 applied about 14 to about 29 in
comparison with the diaphragms of Comparative Examples 1 and 2 using the engineering plastic
although the paint was applied. % Weight reduction has been achieved. Moreover, the
diaphragms of Examples 1 and 2 have remarkably excellent Young's modulus, specific modulus
of elasticity and internal loss compared to Comparative Examples 1 and 2. Moreover, when
Example 1 and 2 and the comparative example 3 are compared, it turns out that internal loss is
remarkably improved by apply | coating a coating material. Furthermore, as apparent from
comparison between FIG. 1 and FIGS. 2 and 3, the speaker member of the present invention
extends smoothly without the characteristic of the vicinity of fh becoming a discontinuous
resonance peak. Moreover, when FIG. 1 and FIG. 2 are compared, it turns out that harmonic
distortion (especially secondary distortion) is notably reduced by the member for speakers of this
invention. This is due to the fact that the internal loss was improved by applying the paint.
[0035]
According to the present invention, by combining and using a film formed of syndiotactic
polymer and a paint, the internal loss is large while having high elasticity and high strength, and
it is lightweight and inexpensive. A speaker member is obtained.
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