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JP2003174694

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This translation is machine-generated. It cannot be guaranteed that it is intelligible, accurate,
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DESCRIPTION JP2003174694
[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a
diaphragm for a speaker, a speaker mounted with the diaphragm, and a diaphragm for a panel
type microphone.
[0002]
2. Description of the Related Art Speakers are widely used in home theaters, electronic musical
instruments, theaters and various halls. A speaker diaphragm serving as a sound source of such a
speaker is considered to be suitably made of a material that is light in weight, has a high tensile
modulus, and has a large internal loss of energy, and conventionally, paper, polypropylene resin,
and foamed polypropylene resin are used as materials. What has been used.
[0003]
However, it is difficult for the diaphragm made of the above-mentioned conventional materials to
simultaneously satisfy all of the lightness, tensile modulus, and internal loss of energy at the
same time.
[0004]
On the other hand, with the advent of DVDs, as diaphragms for speakers, those having flat
frequency characteristics in a wide reproduction band are required in order to reproduce a sense
11-05-2019
1
of reality and a sense of expansion.
[0005]
Furthermore, flat-panel speakers that make use of the principle of divided vibration have recently
been attracting attention.
Unlike the conventional bowl-shaped speaker, the flat speaker vibrates the entire surface of the
diaphragm in a complicated sawtooth-like manner, so distortion of the sound is small and
localization of the sound is small even if the listening position deviates in almost all frequency
bands. It has non-directivity that does not shift, and exhibits excellent sound performance such as
exhibiting flat frequency characteristics.
Furthermore, flat-panel speakers do not require a speaker box, so they are excellent in lightness,
space saving and fashion, and are expected as new sound sources. Therefore, it is required to
provide a material that is more excellent in divided vibration characteristics as a flat plate
speaker diaphragm material.
[0006]
SUMMARY OF THE INVENTION As described above, the present invention is a speaker
diaphragm excellent in lightness and tensile elastic modulus and good also in internal energy
loss, and further has little distortion of sound and no directivity. It is an object of the present
invention to provide a flat speaker diaphragm having flat frequency characteristics in a wide
reproduction band, a speaker using such a diaphragm, and a diaphragm for a panel type
microphone.
[0007]
SUMMARY OF THE INVENTION The present invention provides (1) a thickness of 0.5 to 50 mm
and a weight per unit area of 50 to 2000 g / m @ 2 selected from thermoplastic resin foam,
paperboard or cardboard. A diaphragm for a speaker, characterized in that the base material and
the fiber-reinforced thermoplastic resin sheet containing reinforcing fibers continuously
arranged in one direction or two directions orthogonal to one another, (2) fiber reinforced The
reinforcing plate contained in the thermoplastic resin sheet is a glass fiber, the volume ratio of
the reinforcing fibers contained in the diaphragm for a speaker according to the above (1), (3)
the fiber reinforced thermoplastic resin sheet is 40 to The diaphragm for a speaker according to
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2
(1) or (2) according to (1) or (2), characterized in that the reinforcing fibers are continuously
arranged in two directions orthogonal to each other at 80%, (4) a fiber-reinforced thermoplastic
resin sheet of The speaker diaphragm according to any one of the above (1) to (3), wherein the
tensile elastic modulus at 5 ° C. is 10000 MPa or more in at least one of the extrusion direction
and the width direction. The diaphragm for a speaker according to any one of the above (1) to
(4), wherein the base material is made of a polystyrene resin foam, and the overall thickness of
(6) is 0.7 to 17 mm, 25 The diaphragm for a speaker according to any one of the above (1) to (5),
which has a tensile modulus of elasticity at 800 ° C. of 800 to 3000 MPa, (7) is characterized as
being used as a diaphragm for a planar speaker The speaker diaphragm according to any one of
(1) to (6), (8) a speaker formed by attaching the speaker diaphragm according to any one of (1)
to (7), (9 )heat Base material of 0.5 to 15 mm in thickness and 50 to 2000 g / m 2 in weight per
unit area, which is selected from plastic resin foam, paperboard or cardboard, and is
continuously arranged in one direction or in two directions orthogonal to each other According
to another aspect of the present invention, there is provided a diaphragm for a panel type
microphone, characterized in that the fiber reinforced thermoplastic resin sheet containing the
reinforced fiber is laminated.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION In the speaker diaphragm of the present
invention, the thickness selected from thermoplastic resin foam, paperboard or cardboard is 0.5
to 50 mm, and the weight per unit area is 50 to 2000 g / A m2 base material and a fiberreinforced thermoplastic resin sheet including reinforcing fibers continuously arranged in one
direction or in two directions orthogonal to one another are laminated.
By adopting such a configuration, the speaker diaphragm according to the present invention
efficiently divides the entire surface of the diaphragm in a complicated sand-like shape
efficiently, so there is less distortion of sound, excellent non directivity, and a wide reproduction
band. The diaphragm has a flat frequency characteristic.
[0009]
The speaker diaphragm of the present invention (hereinafter simply referred to as a diaphragm).
The thickness of the above-mentioned substrate which constitutes) is 0.5-50 mm, preferably 0.5-
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3
35 mm, and more preferably 1-15 mm. If the thickness of the base material is less than 0.5 mm,
physical properties such as bending strength and tensile modulus may be insufficient to
withstand vibration. On the other hand, if the thickness is too thick, the input required to vibrate
the diaphragm becomes too large, which may deteriorate the conversion efficiency from input to
sound.
[0010]
The thickness of the base material in the present specification, the thickness of the fiberreinforced thermoplastic resin sheet to be described later, and the thickness of the entire
diaphragm will be measured based on the photograph of the vertical cross section of the
diaphragm. Photograph the 10-point vertical cross-section photograph from the end to the other
end at approximately equal intervals, and calculate the arithmetic mean of each thickness
obtained from the photo, the thickness of the substrate, the thickness of the fiber reinforced
thermoplastic resin sheet, the diaphragm The thickness of the whole.
[0011]
The weight per unit area of the diaphragm is 50 to 2000 g / m 2. When the thickness of the
diaphragm is 0.5 mm or more and less than 15 mm, the weight per unit area is preferably 50 to
1500 g / m 2 When the thickness of the diaphragm is 15 mm or more and less than 50 mm, the
weight per unit area is preferably 400 to 2000 g / m 2.
If the weight per unit area is less than 50 g / m 2, physical properties such as tensile modulus
may be insufficient. If it exceeds 2000 g / m 2, it is necessary to vibrate the diaphragm. Because
the input is too large, the conversion efficiency from input to sound may be degraded.
[0012]
The weight per unit area (g / m 2) of the substrate in the present specification is the weight of
the measurement piece sampled from the substrate before the fiber-reinforced thermoplastic
resin sheet and the like are laminated. It is obtained by dividing by the area of the plane of the
piece.
[0013]
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After the base material and the fiber reinforced thermoplastic resin sheet and the like are
laminated, the weight of the fiber reinforced thermoplastic resin sheet and the like laminated on
the base material is subtracted from the weight of the measurement piece sampled from the
diaphragm And the area of the plane of the measurement piece.
The weight of the fiber-reinforced thermoplastic resin sheet and the like laminated on the
substrate can be calculated based on the thickness of the sheet and the like, the area of the plane
of the sheet and the density of the sheet and the like.
[0014]
The raw material which comprises the base material of the diaphragm for speakers of this
invention is selected from a thermoplastic resin foam, a paperboard, or corrugated paper.
[0015]
Examples of the above-mentioned paperboard and corrugated paper include a commonly used
thick paper, and a structure in which a corrugated paper is sandwiched between flat papers.
Moreover, as a thermoplastic resin foam, the plate-shaped foam which consists of thermoplastic
resins, such as a polystyrene resin, a polypropylene resin, a polyethylene resin, polyvinyl chloride
resin, polyvinylidene chloride resin, is illustrated.
[0016]
Among these thermoplastic resin foams, a polystyrene resin foam produced by an extrusion foam
molding method is preferable from the viewpoint of physical properties, water resistance and
processability.
[0017]
When the base material of the diaphragm of the present invention is made of a thermoplastic
resin foam, the density of the foam is preferably 0.025 to 0.2 g / cm3, and is preferably 0.06 to
0.15 g / cm3. It is more preferable that
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5
The thickness of the thermoplastic resin foam is preferably 0.5 to 35 mm, and more preferably
0.5 to 15 mm.
[0018]
If the density of the thermoplastic resin foam is less than 0.025 g / cm 3, physical properties
such as tensile modulus may be insufficient, and vibration may not be tolerated. On the other
hand, if the density exceeds 0.2 g / cm 3, the input for vibrating the diaphragm becomes too
large, and the conversion efficiency from input to sound may be degraded. Similarly, if the
thickness of the foam is less than 0.5 mm, physical properties such as tensile strength may be
insufficient, and vibration may not be tolerated. On the other hand, if the thickness exceeds 35
mm, the input for vibrating the diaphragm becomes too large, so that the conversion efficiency
from input to sound may be deteriorated.
[0019]
In the present specification, when the substrate is composed of a thermoplastic resin foam, the
density of the foam is a value obtained by dividing the weight per unit area of the foam
determined by the above method by the thickness of the foam. It is obtained by converting the
unit.
[0020]
When the base material of the diaphragm of the present invention is formed of a thermoplastic
resin foam, the average cell diameter of the foam is preferably 0.05 to 1 mm.
When the average cell diameter is 0.05 to 1 mm, the diaphragm is excellent in the stability of the
sound quality, and the adhesion with the fiber-reinforced thermoplastic resin sheet described
later is improved, so that the physical properties such as the good tensile elastic modulus It will
be shown.
[0021]
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6
The average cell diameter of the thermoplastic resin foam is determined as follows. First, the
vertical cross section in the width direction of the foam is enlarged by a microscope to obtain an
enlarged view of a predetermined magnification, and the reference line of length 3000 μm is the
width of the foam at a position 300 μm in the thickness direction from the foam surface in this
enlarged view. Pull in the direction. Next, the number of all the cells crossing the reference line is
counted, and the average cell diameter of the foam is determined according to the following
equation (1). This operation is performed on the front and back surfaces of the foam, and the
arithmetic mean value of the average cell diameters obtained for the front and back surfaces is
taken as the average cell diameter in the width direction.
[0022]
Similarly, in the extrusion direction of the thermoplastic resin foam, an enlarged view of the
vertical cross section in the extrusion direction of the foam is obtained, and a reference of 3000
μm in length at a position 300 μm inside in the thickness direction from the foam surface in
this enlarged view. A line is drawn in the extrusion direction, and the number of all bubbles
intersecting the reference line is counted, and the average cell diameter in the extrusion direction
of the foam is determined by the following equation (1). This operation is performed on the front
and back surfaces of the foam, and the arithmetic mean value of the average cell diameters
obtained for the front and back surfaces is taken as the average cell diameter in the extrusion
direction.
[0023]
Next, the average of the average cell diameter in the width direction and the extrusion direction
is determined, and the average value is taken as the average cell diameter of the thermoplastic
resin foam.
[0024]
Average bubble diameter (μm) = 3000 bubbles number of bubbles ... (1)
[0025]
When the base material of the diaphragm of the present invention is formed of a thermoplastic
resin foam, the open cell ratio of the foam is preferably 50% or less, more preferably 30% or less,
and still more preferably 10% or less.
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When the open cell rate exceeds 50%, the durability may be lowered, or the sound quality may
be deteriorated due to water absorption or absorption.
[0026]
The open cell ratio of the thermoplastic resin foam is the apparent volume of the foam: Va (cm3),
the true volume of the foam: Vx (cm3), the weight of the foam: W (g), the basis of the foam
Density of the material resin: ρ (g / cm 3).
The apparent volume of the foam is the apparent volume obtained from the outer dimension of
the sample, and the true volume of the foam is the volume of the base resin constituting the foam
and the independent volume within the foam. It is the sum of bubble volume and bubble total
volume. Therefore, the volume percentage (open cell rate) of the open-celled cells is determined
by the following equation (2).
[0027]
Open cell rate (%) = (Va-Vx) × 100 / (Va-W / ρ) (2)
[0028]
In the measurement of the apparent volume, the true volume, and the weight of the
thermoplastic resin foam, a sample having a length of 25 mm, a width of 40 mm, and a thickness
of 25 mm is cut out of the foam and used.
However, when the thickness of one sample is less than 25 mm, a plurality of samples are
stacked and used so as to have a thickness of about 25 mm.
[0029]
The true volume of the thermoplastic resin foam is determined using the air comparison type
hydrometer according to ASTM D-2856-70 (Procedure C) for the above-mentioned sample.
11-05-2019
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[0030]
Examples of the method for producing the thermoplastic resin foam include an extrusion foam
molding method, an in-mold molding method of foam beads, and the like.
However, the extrusion foam molding method is preferable because the physical properties,
water resistance and processability of the resulting foam are excellent.
[0031]
In the extrusion foam molding method described above, the thermoplastic resin and the additive
such as the bubble regulator added as necessary are heated, melted and kneaded in the extruder,
and then the foamability obtained by injecting the foaming agent and heating and kneading The
resin composition can be obtained by adjusting it to a foaming aptitude temperature and
extrusion foaming into the atmosphere from the inside of an extruder to form a sheet, a plate or
the like. In addition, when extruding a foamable resin composition from an extruder, it is formed
as a sheet form, plate shape, etc. by letting a flat die and a circular die pass.
[0032]
When a flat die is used in the extrusion foam molding method, it is possible to obtain a sheet-like
or plate-like foam by taking out the extruded foam while passing it through a cooling roll or a
forming device as necessary. .
[0033]
When a circular die is used, an extruded and foamed tubular foam is allowed to pass over the
surface of a cylindrical mandrel and cooled, and then the tubular foam is cut open along the
extrusion direction to obtain a sheet-like foam. You can get it.
The sheet-like foam cut and opened along the extrusion direction is again passed through the
heating furnace to be heated and softened, and then stretched in the extrusion direction of the
sheet or stretched in the extrusion direction and width direction of the sheet As a result, a plate-
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like foam having excellent bending strength and good smoothness can be obtained.
[0034]
In addition, the foam extruded in a cylindrical shape using a circular die can be formed into a
plate by bonding the inner surfaces of the foam by clamping between the rolls without passing
through the mandrel surface.
[0035]
Also, as long as the foam is extruded into a sheet, it can be made into a thick foam by pasting
together.
[0036]
As a foaming agent used for the extrusion foam molding, any of a physical foaming agent and a
decomposition type foaming agent can be used, but a physical foaming agent is used in that a
foam having a high foaming ratio can be easily obtained. Is preferred.
The physical blowing agent is an inorganic type such as carbon dioxide, nitrogen, air, water, etc.,
lower aliphatic hydrocarbon such as propane, n-butane, i-butane, n-pentane, i-pentane, hexane,
etc .; cyclopentane And lower aliphatic hydrocarbons such as cyclohexane; lower aliphatic
alcohols such as methyl alcohol and ethyl alcohol; 1-chloro-1,1-difluoroethane,
pentafluoroethane, 1,1,1,2-tetrafluoroethane, 1 Organic compounds such as halogenated
hydrocarbons such as 1,1-difluoroethane, ethers such as dimethyl ether, methyl ethyl ether and
diethyl ether are used.
[0037]
These foaming agents can be used singly or in combination of two or more, and it is also possible
to use a decomposable foaming agent and a physical foaming agent in combination or to use an
inorganic physical foaming agent and an organic physical foaming agent in combination. It is
possible.
In addition, when the decomposition type foaming agent is used in combination with the physical
11-05-2019
10
foaming agent, the cell diameter adjusting effect can be obtained.
[0038]
The amount of the foaming agent used varies depending on the type of the foaming agent and
the density of the foam to be obtained. For example, the standard of the addition amount of the
foaming agent for obtaining a foam of 0.025 to 0.2 g / cm3, which is a preferable density of the
diaphragm, is 0.5 for the organic physical foaming agent per 100 parts by weight of the base
resin. The amount is about 10 to 10 parts by weight, about 0.2 to 5 parts by weight with the
inorganic physical blowing agent.
[0039]
When the thermoplastic resin foam constituting the substrate is formed using the organic
physical foaming agent, the remaining amount of the organic physical foaming agent in the foam
is relative to 1 kg of the substrate resin constituting the foam. It is preferably 0.3 mol or less,
more preferably 0.15 mol or less. A diaphragm using a base material composed of a foam
configured in this manner is preferable because the change with time of the shape, size, physical
characteristics, etc. with time is extremely small and it is particularly excellent in terms of sound
quality stability. .
[0040]
As a method of adjusting the remaining amount of the organic physical foaming agent in the
thermoplastic resin foam, combining the foaming agents having different gas permeation rates,
adjusting the open cell rate of the foam, adjusting the curing period of the foam And other
methods.
[0041]
The amount of the remaining organic foaming agent in the thermoplastic resin foam can be
determined by placing the foam sample in a lidded sample bottle containing toluene, immersing
for 24 hours and stirring to make the foaming agent in the foam into toluene After dissolving in
effervescent agent, the toluene in which the foaming agent is dissolved can be collected by a
microsyringe, subjected to gas chromatography analysis, and determined by the internal
standard method.
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11
[0042]
Examples of the cell regulator include inorganic powders such as talc and silica, acid salts of
polyvalent carboxylic acids, and reaction mixtures of polyvalent carboxylic acids with sodium
carbonate or sodium bicarbonate.
It is preferable to add about 0.025 to 5 parts by weight of the cell regulator per 100 parts by
weight of the base resin.
If necessary, additives such as a heat stabilizer, an ultraviolet absorber, an antioxidant, a colorant,
an antistatic agent, and a conductivity imparting agent can be appropriately blended.
[0043]
The fiber-reinforced thermoplastic resin sheet constituting the diaphragm of the present
invention includes reinforcing fibers continuously arranged in one direction or in two directions
orthogonal to each other. That is, the fiber-reinforced thermoplastic resin sheet is constituted by
impregnating a reinforcing resin continuously arranged in one direction or two directions
orthogonal to each other with a thermoplastic resin. A laminate comprising such a fiberreinforced thermoplastic resin sheet and a base material is excellent in physical properties such
as tensile modulus and flexural modulus.
[0044]
Examples of the reinforcing fibers include glass fibers, carbon fibers, boron fibers, metal fibers,
ceramic fibers, polyester fibers, vinyl chloride / acrylonitrile copolymer fibers, polyvinyl alcohol
fibers and the like, but the tensile elasticity of the fiber reinforced resin sheet It is preferable to
use a glass fiber which effectively strengthens the ratio etc. and is excellent in dimensional
stability.
[0045]
As resin which comprises the said fiber reinforced thermoplastic resin sheet, thermoplastic
resins, such as polystyrene resin, polypropylene resin, polyethylene resin, polyvinyl chloride
resin, polyvinylidene chloride resin, unsaturated polyester resin, are illustrated.
11-05-2019
12
[0046]
40-80% of the volume ratio of the glass fiber in a fiber reinforced thermoplastic resin sheet is
preferable.
If the volume ratio is less than 40%, there is a possibility that the tensile elastic modulus etc. can
not be strengthened, and if it exceeds 80%, the amount of the thermoplastic resin to be
impregnated is too small and the whole sheet may become brittle. .
[0047]
The tensile modulus of elasticity of the fiber-reinforced thermoplastic resin sheet is preferably
10000 MPa or more in at least one of the extrusion direction and the width direction, and more
preferably 10000 MPa or more in both the extrusion direction and the width direction.
When such a fiber-reinforced thermoplastic resin sheet is used, a diaphragm exhibiting excellent
frequency characteristics in a high sound range can be obtained, and a diaphragm suitable as a
diaphragm for a flat speaker having split vibration characteristics can be obtained. The upper
limit of the tensile modulus of elasticity is approximately 30,000 MPa.
[0048]
The thickness of the fiber reinforced thermoplastic resin sheet is preferably 0.1 to 1.0 mm. When
the thickness is 0.1 to 1.0 mm, the balance between the lightness and the tensile elastic modulus
of the diaphragm is good, and flat frequency characteristics are obtained at a high sound
pressure level by laminating and adhering to the substrate. be able to.
[0049]
The most preferable configuration of the fiber-reinforced thermoplastic resin sheet in the present
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13
invention is a sheet-like reinforcing fiber in which a plurality of continuous fibers composed of
long glass fibers having a fiber diameter of 5 to 36 μm are converged and arranged in one
direction or two directions orthogonal to one another. The sheet | seat made to impregnate a
polypropylene resin is mentioned. Furthermore, among the sheets, those in which the fiber
directions are arranged in two directions orthogonal to each other are more preferable because a
more excellent tensile elastic modulus and bending elastic modulus can be obtained. Specific
examples of the fiber-reinforced thermoplastic resin sheet of this embodiment are those
disclosed in JP-A-7-1788859 and the like.
[0050]
In the diaphragm for a speaker according to the present invention, the substrate and the fiberreinforced thermoplastic resin sheet are laminated, and the fiber-reinforced thermoplastic resin
sheet is laminated via an adhesive on one surface, preferably both surfaces of the substrate.
Manufactured by Usually, the base material and the fiber reinforced thermoplastic resin sheet are
laminated by interposing an adhesive between the two, but the base material is made of a
thermoplastic resin foam and the heat constituting the fiber reinforced resin sheet In the case
where the plastic resin is the same type of resin that can be heat-adhered to the thermoplastic
resin that constitutes the base foam, it is also possible to laminate by heat adhesion.
[0051]
The diaphragm of the present invention preferably has a total thickness of 0.7 to 17 mm, and a
tensile elastic modulus at 25 ° C. of 800 MPa or more in both the width direction and the
direction orthogonal to the width direction. The elastic modulus is more preferably 1000 MPa or
more. The upper limit of the tensile modulus is approximately 4000 MPa. As described above, in
the present specification, the tensile modulus of elasticity of the diaphragm means the tensile
modulus in the width direction and the direction orthogonal to the width direction. When the
thickness is 0.7 to 17 mm and the tensile elastic modulus is 800 MPa or more, it is suitable as a
flat speaker diaphragm having desired divided vibration characteristics.
[0052]
Measurement of the tensile modulus of elasticity of the fiber-reinforced thermoplastic resin sheet
and the diaphragm is carried out using a dumbbell-shaped No. 1 type (the distance between
marked lines 40 mm) of JIS K 6301 (1975), in accordance with JIS K 7113 (1981) Measured at a
temperature of 25 ° C., a distance between gripping jigs of 70 mm, and a tensile speed of 10
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mm / min.
[0053]
The diaphragm according to the present invention has an overall thickness of 0.7 to 17 mm,
preferably 0.7 to 12 mm, and is obtained at 25 ° C. as determined by dynamic viscoelasticity
measurement of a bending method giving vibration distortion at a frequency of 1 Hz. The value
of tan δ is preferably 0.04 or more, more preferably 0.04 to 0.07.
When the thickness of the diaphragm and the value of tan δ are in the above range, the sound
pressure level in the middle to high range is high, the diaphragm becomes excellent in obtaining
flat frequency characteristics, and is particularly excellent as a diaphragm for flat speakers It
becomes. The upper limit of tan δ is approximately 0.2.
[0054]
The measurement of tan δ is performed as follows. First, a strip-shaped test piece of 48 mm in
length, 6 mm in width, and the thickness of the diaphragm as it is is prepared. Next, this test
piece was subjected to Rheometric Scienteific F. E. The dynamic viscoelasticity is measured under
the following conditions using a dynamic viscoelasticity measuring apparatus "Solids Analyzer
RSA II" manufactured by Co., Ltd. and a 3-point bending measuring jig as an accessory thereof.
[0055]
Measurement temperature: 15 to 30 ° C Heating rate: 0.5 ° C / min Bending strain: 0.1%
bending vibration frequency: 1 Hz (6.28 rad / s) Automatic tension adjustment function using 3point bending jig Between chuck: 44.5 mm 3-point bending jig sample central clamp part length:
4 mm 3-point bending jig sample central clamp part width: 6 mm 3-point bending jig sample end
clamp part length: 4 mm 3-point bending jig sample end clamp part width: 6 mm
[0056]
By the above measurement, a continuous curve graph with temperature on the horizontal axis
and tan δ on the vertical axis is obtained.
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The values of tan δ at 25 ° C. on the curve graph obtained as described above are shown in
Table 1 described later.
[0057]
The tensile elastic modulus and tan δ in the diaphragm for a speaker of the present invention
are fibers laminated with the physical properties of the substrate (physical properties such as
substrate resin, density, cell structure etc. when the substrate is a thermoplastic resin foam) The
physical properties of the reinforced thermoplastic resin sheet can be selected and combined to
be within the target range. The value of the tensile modulus of elasticity is largely dependent on
the physical properties of the fiber-reinforced thermoplastic resin sheet, and the value of tan δ
is largely dependent on the physical properties of the substrate.
[0058]
The diaphragm for a speaker according to the present invention comprises a substrate and a
fiber-reinforced thermoplastic resin sheet laminated on at least one surface of the substrate, and
further, a non-foamed thermoplastic resin film, a non-woven fabric, a woven fabric, a paper, It
can be laminated through an adhesive layer as required.
[0059]
As a film of non-foamed thermoplastic resin laminated on the diaphragm, polycarbonate resin,
polystyrene resin, polyethylene resin, polypropylene resin, polycaprolactone resin, methacrylic
acid resin, polyethylene terephthalate, polybutylene terephthalate, etc. Polyester resin,
acrylonitrile-butadiene-styrene copolymer, methacrylic acid-butadiene-styrene copolymer,
styrene-maleic acid copolymer, styrene-acrylic acid copolymer, styrene-acrylic acid ester-styrene
block copolymer Combination, styrene-butadiene-styrene copolymer, styrene-isoprene-styreneblock copolymer, styrene-ethylene-butylene-styrene block copolymer, styrene-ethylenepropylene-styrene Films such as locking copolymer.
[0060]
The diaphragm of the present invention may be provided with a colored layer, or materials
conventionally used as a diaphragm can be combined.
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16
Also, in the case where the diaphragm is made of thermoplastic resin foam as a base material, the
diaphragm is subjected to forming processing such as punching, pressing, thermoforming using a
die, etc. It can be made into desired shapes, such as shape, square shape, and mortar shape.
[0061]
The diaphragm of the present invention is preferably used as a diaphragm for a flat speaker.
The flat speaker diaphragm using the diaphragm of the present invention is extremely excellent
in divided vibration characteristics, has little distortion of sound, exhibits flat frequency
characteristics in almost all frequency bands, and has nondirectionality, No need for a speaker
box.
[0062]
Examples of the speaker to which the diaphragm of the present invention is attached include
those having the diaphragm and a mechanism for driving the diaphragm. Specifically, a voice coil
is attached to a diaphragm, supported by a frame by a damper, an edge or the like, and integrally
obtained with a magnet, a plate, a yoke, a pole or the like. The speaker system can also be formed
by attaching the diaphragm to a cabinet made of wood, metal, synthetic resin, foamed resin, a
composite of these, or the like. In addition, as the simplest structure, there is a flat speaker
including a flat diaphragm and a drive mechanism attached to the diaphragm so as to excite split
resonance of the diaphragm.
[0063]
The laminate of the thermoplastic resin foam of the present invention and the fiber reinforced
thermoplastic resin sheet is limited not only to the speaker diaphragm described above, but also
to a thickness of the substrate of 0.5 to 15 mm as a diaphragm for a panel type microphone It
can be used in the same specification and in the same preferable manner except for the above.
[0064]
EXAMPLES The present invention will be described in more detail by way of examples and
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comparative examples.
[0065]
Example 1 4 parts by weight of butane as a foaming agent and 2 parts by weight of talc as a cell
regulator with respect to 100 parts by weight of polystyrene resin (made by Idemitsu
Petrochemical: HH32, melt flow rate: 1.3 g / 10 min) These are heated, melt-kneaded in an
extruder to form a foamable molten resin, and the foamable molten resin is extruded from a
circular die attached to the tip of the extruder to a low pressure area to form a cylindrical foam,
the cylindrical foam The column was cooled while passing over the side surface of a columnar
cooling device, and then cut in the extrusion direction to obtain a thermoplastic resin foam sheet.
The foamed sheet was processed into a plate through a heating furnace to obtain a polystyrene
resin plate foam.
[0066]
Then, on both sides of the obtained polystyrene resin sheet foam, a fiber reinforced propylene
resin sheet manufactured by Mitsui Chemicals, Inc .: Pregron LF15 / K15 so that the non-woven
fabric surface is the outer surface, hot melt type adhesive manufactured by Mitsui Chemicals, Inc.
Agent: A diaphragm for a speaker was obtained by bonding and laminating through an M-melt
G151.
[0067]
The Pregron LF15 / K15 is further provided on a polypropylene resin sheet containing 70% by
volume ratio of long glass fibers continuously arranged in two directions orthogonal to each
other (tensile elastic modulus is 19000 MPa in both the extrusion direction and the width
direction), and on one side. It is a laminate of non-woven fabric and has a basis weight of 320 g /
m 2.
[0068]
Example 2 In the same manner as in Example 1, a polystyrene resin plate foam was obtained.
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Then, proglen LK 15 / R 45 was adhered to both surfaces of the obtained plate-like foam via a
hot melt adhesive: M-Melt G 151 to obtain a diaphragm for a speaker.
The above proglen LK 15 / R 45 is further subjected to rubbing on a polypropylene resin sheet
(tensile elastic modulus in both the extrusion direction and the width direction is 19000 MPa)
containing 70% by volume ratio of long glass fibers continuously arranged in two orthogonal
directions. Kraft paper (45 g / m 2) is laminated on both sides, and the basis weight is 390 g / m
2.
[0069]
Example 3 To 100 parts by weight of polystyrene resin, 2 parts by weight of butane as a foaming
agent and 1 part by weight of talc as a cell regulator were compounded, and extruded into a low
pressure region from a circular die attached to the tip of an extruder After forming the body, a
polystyrene resin plate-like foam was obtained in the same manner as Example 1, except that the
inside of the tubular foam was attached by clamping the tubular foam between rolls.
[0070]
Subsequently, with the non-woven fabric surface facing the outer surface, the proglen LF15 /
K15 used in Example 1 is adhered to both sides of the obtained polystyrene resin sheet foam via
hot melt adhesive: M-Melt G 151 A diaphragm for the speaker was obtained by stacking the
[0071]
Example 4 1 part by weight of butane as a foaming agent and 6 parts by weight of methyl
chloride as a foaming agent and 1 part by weight of talc as a foam control agent are blended with
100 parts by weight of polystyrene resin After extruding into a zone, a polystyrene resin platelike foam was obtained in the same manner as Example 1 except that it was plate-shaped through
a shaping apparatus.
[0072]
Next, the proglen LF15 / K15 used in Example 1 is adhered and laminated to both surfaces of the
obtained plate-like foam via a hot melt adhesive: M-Melt G 151 so that the non-woven fabric
surface is the outer surface. I got a diaphragm for the speaker.
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A diaphragm for a speaker was obtained by adhering and laminating Pregron PK15 / R100 on
both sides of the plate-like foam obtained in Example 4 via a hot melt adhesive: M-Melt G151.
The above Pregron PK15 / R100 further comprises a double-faced kraft paper (100 g / m 2) on a
polypropylene resin sheet (longitudinal modulus of elasticity in the extrusion direction of 10000
MPa or more) containing long glass fibers continuously arranged in one direction. And have a
basis weight of 350 g / m 2.
[0073]
Comparative Example 1 A diaphragm for a speaker comprising only a polypropylene resin plate
foam having a polypropylene resin (manufactured by Montel SDK Sunrise, PF-814) as a base
resin was obtained.
[0074]
Comparative Example 2 A diaphragm for a speaker comprising only a polystyrene-based resin
plate foam produced in the same manner as in Example 1 was obtained.
[0075]
Various physical properties of the diaphragms obtained in Examples 1 to 4 and Comparative
Examples 1 and 2 are shown in Table 1.
[0076]
The remaining amount of the foaming agent shown in Table 1 was measured by gas
chromatography by an internal standard method using cyclopentane as an internal standard
substance.
The apparatus used for the measurement is Shimadzu gas chromatograph GC-14B, and the
measurement conditions are as follows.
[0077]
Column temperature 40 ° C Inlet temperature 200 ° C Detector temperature 200 ° C Carrier
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gas Nitrogen gas Carrier gas flow rate 3.5 ml / min Column SHINWA CHEMICAL INDUSTRIES,
LTD. Silicone DC550 20% Column length: 4.1 m, column inner diameter Support: Chromosorb
AW-DMCS, mesh 60-80 detector: FID sample preparation solvent: toluene correction factor: 1.13
(butane)
[0078]
The tensile modulus of elasticity of the diaphragm shown in Table 1 was measured according to
JIS K7113 (1981) using a test piece of dumbbell-shaped No. 1 type (distance between marks of
40 mm) according to JIS K 6301 (1975).
However, the test conditions were measured at a temperature of 25 ° C. with a distance
between gripping jigs of 70 mm and a tensile speed of 10 mm / min.
[0079]
As described above, the speaker diaphragm of the present invention is lightweight, has a high
tensile elastic modulus, and is suitable as a speaker diaphragm.
In particular, when a polystyrene-based resin foam sheet is used as a substrate, water resistance
and thermoformability can be imparted, and the diaphragm for speakers can be optimized.
[0080]
In addition, when the diaphragm for a speaker of the present invention is used as a diaphragm of
a flat speaker, the entire surface of the diaphragm efficiently vibrates in a complicated jagged
shape, exhibits excellent flat frequency characteristics, and is suitable for no directivity of sound.
It exhibits excellent characteristics such as excellent characteristics.
[0081]
For this reason, the speaker to which the diaphragm of the present invention is attached is also
suitable as a flat panel speaker incorporated in a ceiling panel, display, computer, CD player,
vehicle component, bulletin board, blackboard, package, greeting card, electronic musical
instrument, etc. is there.
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[0082]
Moreover, the panel-type microphone diaphragm of the present invention exhibits excellent
acoustic performance as in the speaker diaphragm of the present invention.
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