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JP2003289594

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DESCRIPTION JP2003289594
[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a
diaphragm used for a small micro speaker and receiver particularly used for a portable telephone
or the like. The present invention also relates to a polyamideimide resin and a polyimide resin
used for the speaker diaphragm.
[0002]
2. Description of the Related Art FIG. 3 shows a cross section of the internal structure of a small
speaker 4 'conventionally used in a speaker unit 2 such as a portable telephone 1 of this type as
shown in FIG. The diaphragm 3 ′ is incorporated into the speaker 4 ′ after pressing and
forming a sheet of polyethylene or the like into a shape shown in FIG. 3 with a heated male and
female molds. That is, the diaphragm 3 'is formed with the peripheral edge portion 3c' on the
outer periphery of the acoustic radiation dome portion 3a 'and the outer edge 3d' bonded to the
frame 17 'on the outer periphery. Thus, the end of the voice coil bin 6 on which the voice coil 5
′ is wound is bonded to the boundary 3 b ′ of the edge 3 c ′ of the diaphragm 3 ′ and the
outer periphery of the diaphragm 3 ′ with the dome 3 a ′. 'Is suspended in the magnetic gap 8'
of the magnetic circuit 15 'assembled around the magnet 14'.
[0003]
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1
Polyethylene naphthalate (PEN) and polyetherimide (PEI) have been used as diaphragm materials
used for the speaker having the above-mentioned structure. In addition, vibration using a
polyimide (see, for example, page 1 of JP-A-51-6014), and a structure different from the small
speaker but using polyamideimide and mica and further embedding a coil in a diaphragm. There
is also a plate (see, for example, page 1 of JP-A-2000-115884).
[0004]
Speakers used in mobile phones and the like are becoming smaller at a remarkable speed. The
diameter of 12 mm shown in FIG. 3 is the current size and is in the process of transitioning to the
direction of 5 to 10 mm in FIG. In addition, a receiver of a cellular phone is required to obtain
good sound quality without pressing the ear. Then, it is required that the low-pitched resonance
frequency f0 be as small as possible as a measure for making the sound quality good, but in
general, it is necessary to make the thickness very thin in order to make f0 small. In the case of
conventional materials, for example, in the case of PEN, since it has high crystallinity, when it is
molded thin, dimensional stability is poor and molding time is prolonged. When the thickness is
reduced, the surface rigidity is reduced, which causes problems such as poor impact resistance of
the speaker. In PEI, the elastic modulus is lower than that of PEN, and even if it is thicker than
PEN, although it is possible to reduce f0, the dimensional accuracy is poor. The rolling of the
diaphragm is large and good sound quality can not be obtained. Generally, melt extrusion film
formation is performed, the film thickness accuracy is poor, the sound quality of the speaker
varies, and as a result, there are problems such as the productivity becoming worse. Therefore,
the present invention mainly aims to solve these problems.
[0005]
SUMMARY OF THE INVENTION In order to achieve the above object, the present invention takes
the following technical measures. a) By using a material having a small elastic modulus, the
thickness of the diaphragm can be increased even if f0 is set small. b) In order to obtain good
sound quality without rolling even with a thin diaphragm, it is necessary to increase the loss
tangent tan δ (= loss modulus / storage modulus). c) In order to accurately carry out film
production, it is preferable that the material be amorphous and be soluble in a solvent, and the
film should be produced by casting a resin varnish. d) In order to implement the diaphragm with
high dimensional accuracy and a short pitch time, it is important that the diaphragm be noncrystalline and that the temperature dependence of the elastic modulus during melting be
appropriately small. It has been found that materials satisfying all of these characteristics are a
polyamideimide resin and a polyimide resin.
11-05-2019
2
[0006]
That is, the present invention is the following speaker diaphragm and the polyamideimide resin
and polyimide resin used therefor. A first aspect of the present invention is a speaker diaphragm
characterized in that a polyamide imide resin film or a polyimide resin is formed into a dome
shape.
[0007]
A second aspect of the present invention is the speaker vibration according to the first aspect,
wherein the polyamide-imide resin film has a tensile elastic modulus of 3500 MPa or less and
500 MPa or more and a loss tangent tan δ at 20 ° C. of 0.025 or more. It is a board.
[0008]
A third feature of the present invention is that the polyamideimide resin contains at least one
component selected from the group consisting of polyether, polyester, polyacrylonitrilebutadiene copolymer, polycarbonate diol and dimer acid as a copolymerization component. It is a
speaker diaphragm according to claim 1 or 2.
[0009]
A fourth aspect of the present invention is characterized in that the polyamideimide resin is
dissolved in an independent solvent selected from the group consisting of ethanol, toluene,
cyclohexanone, cyclopentanone and tetrahydrofuran, or in a mixed solvent of 2 or more types in
5% by weight or more. A speaker diaphragm according to any one of claims 1 to 3.
[0010]
A fifth aspect of the present invention is the speaker diaphragm according to any one of the first
to fourth aspects, wherein the polyamideimide resin contains a monomer having an isophorone
residue as a copolymerization component as an essential component.
[0011]
A sixth aspect of the present invention is the speaker according to any one of the first to fifth
aspects, further comprising an antistatic layer containing 1 to 50 parts by weight of the antistatic
agent with respect to 100 parts by weight of the binder resin. It is a diaphragm.
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3
[0012]
A seventh aspect of the present invention is the speaker vibration according to any one of the
first to fifth aspects, wherein the polyamideimide resin layer film contains 1 to 50 parts by
weight of the antistatic agent based on 100 parts by weight of the polyamideimide resin. It is a
board.
[0013]
The eighth aspect of the present invention is a polyamideimide resin for a speaker diaphragm
characterized in that a tensile elastic modulus is 3500 MPa or less and 500 MPa or more, and a
loss tangent tan δ at 20 ° C. is 0.025 or more.
[0014]
The ninth aspect of the present invention is characterized in that it contains at least one
component selected from the group consisting of polyether, polyester, polyacrylonitrilebutadiene copolymer, polycarbonate diol and dimer acid as a copolymerization component. It is
polyamide-imide resin for speaker diaphragms as described in these.
[0015]
The tenth aspect is characterized in that it is dissolved in an amount of 5% by weight or more in a
single solvent selected from ethanol, toluene, cyclohexanone, cyclopentanone and
tetrahydrofuran or a mixed solvent of two or more. It is a polyamide imide resin for a speaker
diaphragm.
[0016]
The eleventh aspect is a polyamideimide resin for a speaker diaphragm according to any one of
the eighth to tenth aspects, wherein a monomer having an isophorone residue as a
copolymerization component is an essential component.
[0017]
A twelfth aspect of the present invention is a speaker diaphragm characterized in that a
polyimide resin film having a tensile elastic modulus of 3500 MPa or less and 500 MPa or more
and a loss tangent tan δ at 20 ° C. of 0.025 or more is formed into a dome shape. is there.
11-05-2019
4
[0018]
A thirteenth aspect of the present invention is characterized in that the polyimide resin contains,
as a copolymerization component, at least one component selected from the group consisting of
polyether, polyester, polyacrylonitrile-butadiene copolymer, polycarbonate diol and dimer acid. It
is a speaker diaphragm of Claim 1 or 12.
[0019]
The polyimide resin is dissolved in an independent solvent selected from the group consisting of
ethanol, toluene, cyclohexanone, cyclopentanone and tetrahydrofuran or a mixed solvent of two
or more kinds in an amount of 5% by weight or more. It is a speaker diaphragm according to
item 1 or 12 or 13.
[0020]
A fifteenth aspect of the present invention is the speaker diaphragm according to any one of the
first to twelfth aspects, wherein the polyimide resin contains, as an essential component, a
monomer having an isophorone residue as a copolymerization component.
[0021]
The speaker vibration according to any one of claims 12 to 15, wherein an antistatic layer
containing 1 to 50 parts by weight of the antistatic agent is further laminated with respect to
100 parts by weight of the binder resin. It is a board.
[0022]
A seventeenth aspect of the present invention is the speaker according to any one of the twelfth
to fifteenth aspects, wherein the polyimide resin film contains 1 to 50 parts by weight of the
antistatic agent with respect to 100 parts by weight of the polyimide resin. It is a diaphragm.
[0023]
A eighteenth aspect of the present invention is the polyimide resin for a speaker diaphragm,
wherein the tensile elastic modulus is 3500 MPa or less and 500 MPa or more, and the loss
tangent tan δ at 20 ° C. is 0.025 or more.
[0024]
Claim 19 is characterized in that it contains at least one component selected from the group
consisting of polyether, polyester, polyacrylonitrile-butadiene copolymer, polycarbonate diol and
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5
dimer acid as a copolymerization component. It is a polyimide resin for speaker diaphragms as
described in these.
[0025]
The twentieth aspect is characterized in that it is dissolved at 5 wt% or more in a single solvent
selected from the group consisting of ethanol, toluene, cyclohexanone, cyclopentanone and
tetrahydrofuran or a mixed solvent of two or more kinds. It is a polyimide resin for speaker
diaphragms as described in these.
[0026]
A twenty-first aspect is the polyimide resin for a speaker diaphragm according to any one of the
eighteenth to twentieth aspects, wherein a monomer having an isophorone residue as a
copolymerization component is an essential component.
[0027]
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention mainly
relates to a diaphragm material of a portable telephone 1 and a speaker diaphragm using the
same.
In the present invention, the dome shape is the shape of a diaphragm obtained by secondary
processing of a flat film by pressure forming, press forming or the like, and is circular or
rectangular and has a central portion having a convex shape. Means
[0028]
Polyamideimide resin and polyimide resin are preferable in that they are amorphous and have
excellent dimensional stability at processing compared to crystalline resin, and the temperature
of viscoelasticity at a temperature higher than the glass transition temperature (Tg) The
dependence is appropriate, and it is easy to be processed into a dome shape as in the present
invention, and the temperature dependence of the viscoelasticity in the vicinity of Tg is suitable
for productivity (see FIGS. 4, 5 and 6). .
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Moreover, in terms of material properties, there is diversity in molecular design, and not only is it
possible to lower the elastic modulus according to the purpose, but also the material of which tan
δ is relatively large, rolling of the diaphragm hardly occurs. Is preferable in that distortion of the
sound quality caused by rolling is reduced.
[0029]
The polyamideimide resin and the polyimide resin used in the present invention are prepared by
a method of producing from an acid component and an isocyanate component (isocyanate
method), or a method of reacting an acid component with an amine to form an amic acid and ring
closure, or acid chloride Component (A) is prepared in a high boiling polar solvent by a known
method such as an acid chloride method prepared from an amine and an amine.
[0030]
When the polyamideimide resin and the polyimide resin of the present invention are produced by
the isocyanate method, they are produced, for example, from the acid component and the
isocyanate component shown below.
[0031]
Examples of the acid component include trimellitic anhydride, ethylene glycol bisanhydro
trimellitate, propylene glycol bis anhydro trimellitate, 1,4-butanediol bis anhydro trimellitate, and
hexamethylene glycol bis anhydro trimellite. Alkylene glycol bisanhydrotrimellitates such as tate,
polyethylene glycol bisanhydrotrimellitate, polypropylene glycol bisanhydrotrimellitate,
pyromellitic anhydride, benzophenone tetracarboxylic acid anhydride, 3,3 ′, 4, 4'-diphenyl
sulfone tetracarboxylic acid anhydride, 3,3 ', 4,4'-diphenyl tetracarboxylic acid anhydride, 4,4'oxyphthalic acid anhydride, terephthalic acid, isophthalic acid, 4,4'-biphenyl Dicarboxylic 4,4'biphenyl ether dicarboxylic acid, 4,4'-benzophenone dicarboxylic acid, pyromellitic acid, 3,3 ',
4,4'-benzophenone tetracarboxylic acid, 3,3', 4,4'-biphenyl Sulfonetetracarboxylic acid, 3,3 ', 4,4'biphenyltetracarboxylic acid, cyclohexanedicarboxylic acid, adipic acid, sebacic acid, azelaic acid,
dodecanedioic acid, maleic acid, fumaric acid, stilbenedicarboxylic acid and the like. .
These acid components can be used alone or in combination.
[0032]
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7
In the case of the polyamideimide resin, among these acid components, trimellitic anhydride,
pyromellitic anhydride and ethylene glycol bisanhydrotrimelitate are preferable from the
viewpoint of reactivity, heat resistance, cost and the like.
Further, more preferably trimellitic anhydride and pyromellitic anhydride, and the
copolymerization amount thereof is 80 mol% or less and 20 mol% or more in the case of using
pyromellitic anhydride from the viewpoint of heat resistance and solubility. When using
trimellitic anhydride, it is 100 mol% or less and 30 mol% or more.
When the content of pyromellitic anhydride exceeds 80 mol%, the solubility in a low boiling point
solvent such as tetrahydrofuran decreases, and an amide type solvent such as
dimethylformamide, dimethylacetamide, N-methyl-2-pyrrolidone, γ -It becomes difficult to
dissolve if a high boiling point solvent such as butyrolactone is not used in combination, but if a
high boiling point solvent is used, drying at the time of film formation described later may be
difficult.
On the other hand, when the content of pyromellitic anhydride is less than 20 mol%, the heat
resistance may be lowered.
If the amount of trimellitic anhydride is less than 30 mol%, the heat resistance may be lowered.
In addition, aliphatic and / or alicyclic dicarboxylic acids can be copolymerized for the purpose of
improving solubility and moldability and reducing tensile modulus.
Preferred examples include aliphatic dicarboxylic acids having a main chain carbon number of 8
or more, such as 1,4-cyclohexanedicarboxylic acid and sebacic acid.
[0033]
In the case of a polyimide resin, one or more of the tetrabasic acids described above for the
polyamideimide resin can be used.
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8
As the acid component, pyromellitic anhydride, ethylene glycol bisanhydro trimellitate, and
benzophenone tetracarboxylic acid anhydride are preferable in terms of reactivity, heat
resistance, cost and the like.
More preferably, it is pyromellitic anhydride, and the copolymerization amount thereof is 90
mol% or less and 20 mol% or more of pyromellitic anhydride from the viewpoint of heat
resistance and solubility.
When the content of pyromellitic anhydride exceeds 90 mol%, the solubility in a low boiling point
solvent such as tetrahydrofuran is lowered, and an amide type solvent such as
dimethylformamide, dimethylacetamide or N-methyl-2-pyrrolidone, γ -It may be difficult to
dissolve unless a high boiling point solvent such as butyrolactone is used in combination.
On the other hand, when the content of pyromellitic anhydride is less than 20 mol%, the heat
resistance may be lowered.
[0034]
As an isocyanate component, for example, dicyclohexyl-4,4'-diisocyanate, 1,3-bis
(isocyanatomethyl) cyclohexane, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate,
diphenylmethane-4,4'- Diisocyanate, 3,3'-Dimethyldiphenylmethane-4,4'-diisocyanate, 3,3'diethyldiphenylmethane-4,4'-diisocyanate, 3,3'-dichlorodiphenylmethane-4,4'-diisocyanate, 3,3 'Dichlorodiphenyl-4,4'-diisocyanate, 4,4'-diisocyanate-3,3'-dimethylbiphenyl, hexamethylene
diisocyanate, isophorone diisocyanate, p-phenylene diisocyanate, m-phenylene diisocyanate
Sulfonates, and the like.
These isocyanate components can be used singly or in combination.
Among these isocyanate components, diphenylmethane-4,4'-diisocyanate, dicyclohexylmethane4,4'-diisocyanate and isophorone diisocyanate are preferable, and isophorone diisocyanate is
more preferable, from the viewpoint of heat resistance, cost and solvent solubility.
11-05-2019
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[0035]
When the polyamideimide resin and / or polyimide resin used in the present invention is
produced by the acid chloride method, the amine component may be 4,4'diaminodicyclohexylmethane, 1,3-cyclohexanebis (methylamine), o-chloro P-phenylenediamine,
p-phenylenediamine, m-phenylenediamine, 4,4'-diaminodiphenylether, 3,4'diaminodiphenylether, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylsulfone, 3,4 'Diaminodiphenyl sulfone, 4,4'-diaminobenzophenone, 3,4'-diaminobenzophenone, 2,2'-bis
(aminophenyl) propane, 2,4-tolylenediamine, 2,6-tolylenediamine, p-xylelin diamine, isophorone
Amine, hexamethylenediamine, p- phenylenediamine, m- phenylenediamine, and the like.
These amine components can be used alone or in combination.
Among these amine components, 4,4'-diaminodiphenylmethane, 4,4'diaminodicyclohexylmethane, isophorone diamine is preferable, and isophorone diamine is more
preferable, in view of heat resistance, cost, solvent solubility and the like.
[0036]
The polyamideimide resin and polyimide resin of the present invention are produced from the
above-mentioned acid (acid chloride) and isocyanate (amine), but from the viewpoint of solubility
and moldability, polyether, polyester, polyacrylonitrile-butadiene copolymer, It is preferable to
copolymerize at least one component selected from the group consisting of polycarbonate diol
and dimer acid.
The amount of copolymerization is preferably 50% by weight or less, more preferably 40% by
weight or less, based on 100% by weight of the resin.
If it exceeds 50% by weight, the glass transition temperature of polyamideimide or polyimide
tends to be low, and the heat resistance of the speaker diaphragm may be deteriorated.
In order to improve the solubility and the moldability, the lower limit is preferably 3% by weight.
11-05-2019
10
[0037]
Furthermore, in order to modify the speaker diaphragm, plasticizers such as dibutyl phthalate
and triphenyl phosphate, higher fatty acids and salts thereof, lubricants such as soybean oil
lecithin and silicone oil, alumina, titanium oxide, calcium oxide, chromium oxide Inorganic
powders such as silicon carbide, calcium carbonate, zinc oxide, α-Fe 2 O 3, talc and kaolin can
also be added.
In addition, a small amount of silicone oil may be copolymerized in order to improve the blocking
resistance at the time of molding.
[0038]
The logarithmic viscosity of the polyamideimide resin and polyimide resin of the present
invention is 0.3 dl / g or more and 1.2 dl / g or less, preferably 0.4 dl / g or more and 1.0 dl / g
or less.
If the logarithmic viscosity is less than 0.3 dl / g, the coating may be brittle and the performance
of the speaker may not be satisfactory. On the other hand, if the logarithmic viscosity exceeds 1.2
dl / g, the solution viscosity of the varnish may become high, which may cause trouble in casting.
[0039]
Examples of solvents used for synthesis of the polyamideimide resin and polyimide resin of the
present invention include amide solvents such as dimethylformamide, dimethylacetamide, Nmethyl-2-pyrrolidone and dimethylimidazolidinone, nitro solvents such as nitrobenzene, and
dimethyl Urea-based solvents such as urea, sulfur-based solvents such as dimethylsulfoxide,
ester-based solvents such as γ-butyrolactone, etc. may be mentioned. Preferred are
imidazolidinone and γ-butyrolactone alone or in combination.
[0040]
The polyamideimide resin and the polyimide resin of the present invention are synthesized by
stirring at 50 to 230 ° C., preferably 80 to 200 ° C. in the above-mentioned solvent when they
11-05-2019
11
are synthesized by the isocyanate method. Amines such as triethylamine, lutidine, picoline,
undecene, triethyldiamine, lithium methylate, sodium methylate, sodium ethylate, potassium
butoxide, alkali metals such as potassium fluoride, sodium fluoride etc., alkaline earth metal
compounds or It may be carried out in the presence of a catalyst such as a metal such as cobalt,
tin or zinc, or a metalloid compound.
[0041]
When the thus-synthesized polyamideimide resin or polyimide resin is dissolved in ethanol,
toluene, cyclohexanone, cyclopentanone, tetrahydrofuran or a mixed solvent thereof, the solvent
is substituted to facilitate drying during film formation. It is preferable to do.
As a method of solvent substitution, for example, a reaction solution (resin varnish) comprising a
high boiling point solvent such as N-methyl-2-pyrrolidone, dimethyl imidazolidinone, or γbutyrolactone is used as a polyamideimide or a poor solvent for polyimide. The high boiling point
polar solvent is reprecipitated in a solvent miscible with the polar solvent (coagulation bath) or in
water.
At that time, in order to effectively elute the high boiling point polar solvent from the resin or to
adjust the elution rate, alcohol solvents such as ethylene glycol and triethylene glycol,
hydrocarbon solvents such as toluene and xylene, acetone Ketone solvents such as methyl ethyl
ketone, ether solvents such as dioxane and ethylene glycol dimethyl ether, ester solvents such as
methyl acetate and ethyl acetate may be added to the resin varnish and the coagulation bath.
Furthermore, the elution of the high boiling polar solvent can be further accelerated by lowering
the polymer concentration of the resin or raising the temperature of the coagulation bath. The
coagulation bath used in the present invention is most preferably water.
[0042]
The method for charging the resin composition into the coagulating bath is not particularly
limited, but in order to produce it continuously and efficiently, it is preferable to discharge from
the pore nozzle.
[0043]
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12
The reprecipitated polymer is filtered, and the solvent is removed by a centrifugal dehydrator or
the like, followed by drying.
Drying can be carried out by a usual method such as hot air drying or vacuum drying.
[0044]
The reprecipitated polymer is redissolved to obtain a resin varnish subjected to the target solvent
substitution. As a solvent used for the redissolution, low boiling point solvents such as alcohol,
toluene, cyclohexanone, cyclopentanone and tetrahydrofuran are preferable. Examples of the
alcohol include monohydric fats such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl
alcohol, n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol, pentyl alcohol, hexyl alcohol, heptyl
alcohol, octyl alcohol and the like. Alcohol, ethylene glycol, propylene glycol, trimethylolpropane,
glycerin, polyhydric alcohol such as pentaerythritol, aromatic alcohol such as benzyl alcohol, etc.,
and it can be selected according to the purpose of use of the resin varnish. Low boiling point
alcohols such as methyl alcohol, ethyl alcohol and propyl alcohol, toluene, cyclohexanone,
cyclopentanone and tetrahydrofuran Masui. Furthermore, solvents other than the above may be
mixed and used.
[0045]
There is no particular limitation on the means for re-dissolving, and it can be dissolved by a usual
method. For example, the resin varnish can be obtained by placing the solvent in a container and
adding the dry polymer little by little at room temperature or under heating while stirring.
[0046]
By casting and drying a resin varnish, a resin film used for a speaker diaphragm can be obtained.
Although the method of casting is not particularly limited, amide solvents such as
dimethylformamide (DMF), dimethylacetamide (DMAc), N-methyl-2-pyrrolidone (NMP) or the like
using polyethylene terephthalate or polypropylene as a base, or ethanol, toluene, The method of
apply | coating and heat-drying the varnish which melt | dissolved in low boiling general purpose
solvents, such as tetrahydrofuran and cyclohexanone, with a well-known method is mentioned.
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13
[0047]
The loudspeaker diaphragm of the present invention is preferably given an antistatic formulation
in order to enhance the workability. The workability referred to here is, for example, making the
films easy to peel off, preventing adhesion of dust, and the like. Examples of antistatic agents
include carbon black, fluorinated carbon, inorganic conductive agents such as doped metal
oxides, polypyrrole and polythiophene polyaniline, etc., of which carbon black is preferred in
terms of balance between antistatic effect and cost. . These antistatic agents may be used alone
or in combination of two or more. The carbon black is not particularly limited, and examples
thereof include furnace for rubber, thermal for rubber, black for color, acetylene black and ketjen
black. In addition, metal salts of carboxylic acids, metal salts of sulfonic acids, nonionic
surfactants, etc. can also be used as low molecular weight organic antistatic agents, but they
adhere to the mold at the time of molding to bleed out on the film surface and die It is preferable
to use an inorganic conductive agent or a high molecular weight organic conductive agent free of
mold contamination because the antistatic agent may contaminate the metal.
[0048]
As the antistatic formulation, an antistatic layer can be separately laminated on the resin layer of
the present invention, or an antistatic agent may be added to the resin film of the present
invention. A polyester resin, an acrylic resin, a polyamide resin, a polyurethane resin, a polyamide
imide resin, a starch etc. is used as a binder resin of the antistatic layer in the case of separately
laminating an antistatic layer, and the antistatic agent is used per 100 parts by weight of the
binder resin. 50 parts by weight is used. The amount is preferably 3 to 40 parts by weight, more
preferably 6 to 30 parts by weight. In the present invention, it is preferable to use, as a binder, a
polyamideimide resin or a polyimide resin, which is the main material of the diaphragm, from the
viewpoint of adhesion and the like. In addition, dispersants necessary for dispersing carbon black
and the like in the antistatic layer, plasticizers such as dibutyl phthalate and triphenyl phosphate,
higher fatty acids and salts thereof, lubricants such as soybean oil lecithin and silicone oil, and
alumina Inorganic powders such as titanium oxide, calcium oxide, chromium oxide, silicon
carbide, calcium carbonate, zinc oxide, α-Fe 2 O 3, talc and kaolin can also be added. On the
other hand, also when adding an antistatic agent to a resin film, 1 to 50 parts by weight of the
antistatic agent is used with respect to 100 parts by weight of the binder resin. The amount is
preferably 3 to 40 parts by weight, more preferably 6 to 30 parts by weight. It is also possible to
add additives as described above.
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[0049]
Moreover, in order to improve the weather resistance of environmental characteristics, a UV
absorber, an antioxidant, etc. may be added, and a well-known UV absorber and antioxidant can
be used. Further, in order to improve the moisture resistance of the environmental
characteristics, an epoxy resin, carbodiimide or the like may be added.
[0050]
The glass transition temperature of the polyamideimide resin and the polyimide resin used in the
present invention is 100 ° C. or more, preferably 120 ° C. or more, and more preferably 140
° C. or more. At 100 ° C. or less, there is a risk of deformation in a high temperature
environment. For example, in the case of polyethylene terephthalate (PET) having a glass
transition temperature of 70 ° C., it deforms in a heat resistance test assuming that the vehicle
is in summer. Although the upper limit of the glass transition temperature is not particularly
limited, it is generally 400 ° C. or less, preferably 350 ° C. or less. If the glass transition
temperature is high, it may be necessary to process at a high temperature during molding, which
may increase the cost. When the glass transition temperature of the polyamideimide resin or
polyimide resin of the present invention is 250 ° C. or higher, the heat resistance is excellent,
and reflow soldering for simplification of the production process becomes possible, which is
preferable.
[0051]
The tensile modulus of elasticity of the polyamideimide resin and polyimide resin of the present
invention is 3500 MPa or less and 500 MPa or more, preferably 3000 MPa or less and 800 MPa
or more, and more preferably 2500 MPa or less and 1000 MPa or more. If it exceeds 3500 MPa,
it is necessary to further reduce the thickness of the diaphragm when lowering f0, which may
lower the dimensional stability and the productivity. Moreover, since it will deform | transform
easily when handling a film as it is less than 500 Mpa, handling becomes difficult. From the
viewpoint of f0 and diaphragm thickness, 2000 MPa or less and 1000 MPa or more are most
preferable.
[0052]
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15
The tan δ of the polyamideimide resin or polyimide resin of the present invention is preferably
0.025 or more. If tan δ is small, the energy can not be relaxed, and the amplitude of the
diaphragm is increased, which may cause rolling or the like. The upper limit of tan δ is not
particularly limited, but is preferably 0.4 or less.
[0053]
When the above-described polyamideimide resin and polyimide resin are used, f0 is small even in
the speaker structure as shown in FIG. 2 and it is possible to have good processability. The
obtained speaker is used, for example, as a speaker unit and / or a receiver unit (not shown) of
the mobile phone shown in FIG.
[0054]
EXAMPLES Examples of the present invention will be shown below, but the scope of the present
invention is not limited to these examples. The evaluation methods in the examples are as
follows.
[0055]
Logarithmic viscosity: 0.5 g is dissolved in 100 ml of N-methyl-2-pyrrolidone and measured at 25
° C. using a Ubbelohde viscosity tube.
[0056]
Tensile modulus: Using a film of 40 mm in length, 10 mm in width and 10 μm in thickness as a
test piece, the tensile modulus of elasticity was measured at a speed of 20 mm / min using a
Toyo Baldwin tensile tester RTM100.
[0057]
Glass transition temperature, tan δ: The film is made into a strip of 15 mm in length and 4 mm
in width and heated at a rate of 4 ° C./min at 110 Hz with a viscoelasticity measuring machine
DVE-V4 as a visco-elasticity measuring machine in tension mode. It was measured.
11-05-2019
16
The inflection point of storage elastic modulus E 'was made into glass transition temperature.
Further, the ratio of the storage elastic modulus to the loss elastic modulus at 20 ° C. was taken
as tan δ.
[0058]
Sound pressure evaluation: Frequency dependence of sound pressure (100 to 10000 Hz) was
measured at N = 30 with an input of 1 mV. The low-temperature resonant frequency f0 is a
frequency at which the simultaneously evaluated impedance has a maximum. The high frequency
resonance frequency Fh is a frequency at which the sound pressure has a maximum value on the
high frequency side.
[0059]
Evaluation of distortion: Measurement at 500 Hz to 1000 Hz was performed as a frequency
suitable for determining the presence or absence of rolling, and the presence or absence of an
abrupt change around 700 Hz was examined. The larger the value at 700 Hz, the more muddy
the sound. If there is an abrupt change, it is estimated to be distortion due to rolling.
[0060]
Air blow test: Air was blown to the diaphragm surface of the speaker 10 mm away with an air
gun having an air jet outlet with an inner diameter of 2.5 mmφ, and the pressure at which the
diaphragm was deformed was determined.
[0061]
Drop test: A load of 100 g was applied to the speaker and allowed to fall spontaneously from a
height of 1.5 m.
11-05-2019
17
It implemented by N = 10 and judged deformation | transformation and a tear of a diaphragm
visually.
[0062]
In Example 1, 0.35 mol of trimellitic anhydride, 0.35 mol of cyclohexanedicarboxylic acid, 0.3
mol of dimer acid, 1.03 mol of isophorone diisocyanate, and 0.02 mol of potassium fluoride are
added to a reaction vessel in γ- It was charged with butyrolactone and adjusted to a
concentration of 50% by weight. The solution was allowed to react for 2 hours at 120 ° C. with
stirring, and then for another 4 hours at 190 ° C. The solution was cooled to room temperature
while being diluted to about 25% with N-methyl-2-pyrrolidone, poured into water with stirring,
reprecipitated, filtered, and dried with hot air at 100 ° C. The logarithmic viscosity of the
obtained polymer was 0.48 dl / g. In a container, 25 parts by weight of this polymer, 37.5 parts
by weight of ethanol and 37.5 parts by weight of toluene are added, and a solution obtained by
dissolving at 40 ° C. is dried into a 50 μm thick biaxially stretched polyester film using a
comma coater. It apply | coated so that thickness might be set to 10 micrometers, and it dried.
Then, it was peeled off from the polyester film and wound up to obtain a roll film of
polyamideimide resin. The tensile modulus of elasticity of this film was 1800 MPa. Moreover, as
a result of viscoelasticity measurement, tan δ at 20 ° C. was 0.038, and the glass transition
temperature was 150 ° C. (see FIG. 4). When the thickness of the roll film was measured, the
accuracy was ± 2%. The film was heated to 175 ° C. in a male-female mold and pressed into a
dome shape shown in FIG. The cooling temperature was 135 ° C., and the pitch time at that time
was 17 seconds. The diaphragm was mounted on a speaker, and sound pressure characteristics,
distortion characteristics, air blow test, and drop test were performed with an input of 1 mV. As a
result, f0 of this speaker is 450 Hz and distortion value at fh of 3000 Hz and 700 Hz is The
distortion was small at -40 dB. In the air blow test, it did not deform even when 11 kgf / cm 2 of
air was blown. In addition, it was all good in drop test.
[0063]
As Example 2, in a reaction vessel, 0.47 mol of trimellitic anhydride, 0.47 mol of
cyclohexanedicarboxylic acid, 0.06 mol of Sannix PP 2000 (polypropylene glycol manufactured
by Sanyo Chemical Industries, Ltd.), 1.01 mol of isophorone diisocyanate, 0.02 mol of potassium
iodide was charged with .gamma.-butyrolactone to adjust the concentration to 50% by weight.
The solution was allowed to react for 2 hours at 120 ° C. with stirring, and then for another 4
hours at 190 ° C. The solution was cooled to room temperature while being diluted to about
25% with N-methyl-2-pyrrolidone, poured into water with stirring, reprecipitated, filtered, and
11-05-2019
18
dried with hot air at 80 ° C. The logarithmic viscosity of the obtained polymer was 0.65 dl / g.
In a container, 25 parts by weight of this polymer, 37.5 parts by weight of ethanol and 37.5 parts
by weight of toluene are added, and a solution obtained by dissolving at 40 ° C. is dried into a
50 μm thick biaxially stretched polyester film using a comma coater. It apply | coated so that
thickness might be 11 micrometers, and it was made to dry. Then, it was peeled off from the
polyester film to obtain a polyamideimide film. The tensile modulus of elasticity of this film was
1600 MPa. Further, as a result of the viscoelastic measurement, tan δ at 20 ° C. was 0.040, and
the glass transition temperature was 200 ° C. When the thickness of the film was measured, the
accuracy was ± 2%. The film was heated to 200 ° C. with a male and female mold, pressed into
a dome shape shown in FIG. 8 and cooled to 160 ° C. The pitch time at that time was 18
seconds. The diaphragm was mounted on a speaker and evaluated in the same manner as in
Example 1. As a result, distortion was small at f0 of 460 Hz, fh of 3000 Hz and 700 Hz at a
distortion value of −40 dB. The air blow test did not deform even when 11 kg / cm 2 of air was
blown, and the drop test was all good.
[0064]
As Example 3, 1 mol of trimellitic anhydride and 0.99 mol of diphenylmethane-4,4'-diisocyanate
were charged into a reaction vessel together with N-methyl-2-pyrrolidone, and the concentration
was adjusted to 20% by weight. The solution was allowed to react for 2 hours at 120 ° C. with
stirring, and then for another 4 hours at 170 ° C. The solution was cooled to room temperature
while diluting to about 15% with N-methyl-2-pyrrolidone. The logarithmic viscosity of the
obtained polymer was 0.68 dl / g. This solution was applied to a 50 μm thick biaxially stretched
polyester film using a comma coater such that the film thickness after drying was 11 μm and
dried. And after peeling off from the polyester film, it dried further and obtained the
polyamidoimide film. The tensile modulus of elasticity of this film was 2900 MPa. Further, as a
result of the viscoelastic measurement, tan δ at 20 ° C. was 0.025, and the glass transition
temperature was 290 ° C. The accuracy of the thickness of this film was ± 1.2%. The film was
also formed into a dome shape at a heating temperature of 300 ° C. and a cooling temperature
of 250 ° C. The pitch time at that time was 25 seconds. This diaphragm was mounted on a
speaker, and the same evaluation as in Example 1 was performed. The f0 was 530 Hz, the fh was
2600 Hz, the distortion at 700 Hz was -28 dB, and there was a slight change in distortion around
700 Hz, but it was not rapid. The air blow test did not deform even when 11 kg / cm 2 of air was
blown, and the drop test was all good. Moreover, even if this film is pressed with a solder iron at
270 ° C. for 1 minute, it does not melt and can cope with reflow soldering.
[0065]
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19
In Example 4, 0.94 mol of trimellitic anhydride, 0.06 mol of Plaxel 220 (polycaprolactone diol
manufactured by Daicel Chemical Industries, Ltd.), 1.02 mol of isophorone diisocyanate, and 0.04
mol of potassium fluoride are contained in a reaction vessel. Charged with butyrolactone to a
concentration of 50% by weight. The solution was allowed to react for 2 hours at 120 ° C. with
stirring, and then for another 4 hours at 190 ° C. The solution was cooled to room temperature
while being diluted to about 25% with N-methyl-2-pyrrolidone, poured into water with stirring,
reprecipitated, filtered, and dried with hot air at 80 ° C. The logarithmic viscosity of the
obtained polymer was 0.55 dl / g. In a container, 25 parts by weight of this polymer and 75 parts
by weight of tetrahydrofuran are added, and a solution dissolved at 40 ° C. is coated on a 50
μm thick biaxially stretched polyester film using a comma coater to a film thickness of 10 μm
and dried. did. Then, it was peeled off from the polyester film to obtain a polyamideimide film.
The tensile modulus of elasticity of this film was 2100 MPa. Further, as a result of the
viscoelastic measurement, tan δ at 20 ° C. was 0.035, and the glass transition temperature was
150 ° C. When the thickness of the film was measured, the accuracy was ± 1.5%. The film was
pressed at 155 ° C. into a dome shape and cooled to 115 ° C. The pitch time at that time was
18 seconds. The diaphragm was mounted on a speaker and evaluated. As a result, f0 was 500 Hz,
fh was 2800 Hz, distortion at 700 Hz was -37 dB, an air blow test was 11 kg / cm2 or more, and
a drop test was all good.
[0066]
As Example 5, 0.70 mol of pyromellitic anhydride, 0.22 mol of trimellitic anhydride, 0.08 mol of
Plaxel 220 (polycaprolactone diol manufactured by Daicel Chemical Industries, Ltd.), 1.02 mol of
isophorone diisocyanate in a reaction vessel. 0.02 mol of potassium fluoride was charged
together with γ-butyrolactone to a concentration of 50% by weight. The solution was allowed to
react for 2 hours at 120 ° C. with stirring, and then for another 4 hours at 190 ° C. The
solution was cooled to room temperature while being diluted to about 25% with N-methyl-2pyrrolidone, poured into water with stirring, reprecipitated, filtered, and dried with hot air at 80
° C. The logarithmic viscosity of the obtained polymer was 0.52 dl / g. In a container, 25 parts
by weight of this polymer and 75 parts by weight of tetrahydrofuran are added, and a solution
dissolved at 40 ° C. is coated on a 50 μm thick biaxially stretched polyester film using a
comma coater to a film thickness of 10 μm and dried. did. Then, it was peeled off from the
polyester film to obtain a polyamideimide resin film. The tensile modulus of elasticity of this film
was 1800 MPa. Further, as a result of the viscoelastic measurement, tan δ at 20 ° C. was
0.040, and the glass transition temperature was 140 ° C. When the thickness of the film was
measured, the accuracy was ± 1.2%. The film was heat melted at 150 ° C., pressed into a dome
shape, and cooled to 100 ° C. The pitch time at that time was 20 seconds. As a result of
mounting this diaphragm on a speaker and evaluating it, f0 is 450 Hz, fh is 3000 Hz, distortion
11-05-2019
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at 700 Hz is -40 dB, air blow test is not deformed even when air of 11 kg / cm2 is blown, and
drop test is all good Met.
[0067]
As Example 6, 0.43 mol of pyromellitic anhydride, 0.43 mol of RIKACID TM EG 200 (ethylene
glycol bisanhydrotrimellitate manufactured by Shin Nippon Rika Co., Ltd.), PCDL L5652
(polycarbonate diol manufactured by Asahi Kasei Corporation) in a reaction vessel 0.14 mol, 1.01
mol of isophorone diisocyanate, and 0.02 mol of potassium fluoride were charged together with
N-methyl-2-pyrrolidone to a concentration of 50% by weight. The solution was allowed to react
for 2 hours at 120 ° C. with stirring, and then for another 4 hours at 190 ° C. The solution was
cooled to room temperature while being diluted to about 25% with N-methyl-2-pyrrolidone,
poured into water with stirring, reprecipitated, filtered, and dried with hot air at 80 ° C. The
logarithmic viscosity of the obtained polymer was 0.45 dl / g. In a container, 25 parts by weight
of the polymer and 75 parts by weight of tetrahydrofuran are added, and a solution dissolved at
40 ° C. is applied using a comma coater to a 50 μm thick biaxially stretched polyester film to a
film thickness of 11 μm and dried. I did. And it peeled from the polyester film and obtained the
polyimide film. The tensile modulus of elasticity of this film was 1200 MPa. Further, as a result of
viscoelasticity measurement, the thickness of a film whose tan δ at 20 ° C. was 0.034 and
whose glass transition temperature was 110 ° C. was measured. The accuracy was ± 2%. The
film was pressed at 120 ° C. into a dome shape and cooled to 70 ° C. The pitch time at that
time was 23 seconds. This diaphragm is mounted on a speaker and evaluated. As a result, f0 is
400 Hz, fh is 2800 Hz, distortion at 700 Hz is -34 dB, and an air blow test does not deform even
when 11 kg / cm 2 of air is blown, a drop test Even the whole number was good.
[0068]
In Example 7, 0.94 mol of RIKASHID TM EG 200 (ethylene glycol bisanhydrotrimellitate
manufactured by Shin Nippon Rika Co., Ltd.), CTBN 1300 × 13 (polyacrylonitrile-butadiene
copolymer manufactured by Ube Industries, Ltd.) 0. 06 mol, 1.02 mol of isophorone diisocyanate,
and 0.02 mol of potassium fluoride were charged together with N-methyl-2-pyrrolidone to a
concentration of 50% by weight. The solution was allowed to react for 2 hours at 120 ° C. with
stirring, and then for another 4 hours at 190 ° C. The solution was cooled to room temperature
while being diluted to about 25% with N-methyl-2-pyrrolidone, poured into water with stirring,
reprecipitated, filtered, and dried with hot air at 80 ° C. The logarithmic viscosity of the
obtained polymer was 0.56 dl / g. In a container, 25 parts by weight of this polymer and 75 parts
by weight of tetrahydrofuran are added, and a solution dissolved at 40 ° C. is coated on a 50
11-05-2019
21
μm thick biaxially stretched polyester film using a comma coater to a film thickness of 10 μm
and dried. I did. And it peeled from the polyester film and obtained the polyimide film. The tensile
modulus of elasticity of this film was 1800 MPa. Further, as a result of the viscoelastic
measurement, tan δ at 20 ° C. was 0.036, and the glass transition temperature was 175 ° C.
When the thickness of the film was measured, the accuracy was ± 1.2%. The film was pressed at
180 ° C. into a dome shape and cooled to 140 ° C. The pitch time at that time was 17 seconds.
This diaphragm was mounted on a speaker and evaluated. As a result, f0 is 450 Hz, fh is 3000
Hz, distortion at 700 Hz is -37 dB, air blow test does not deform even when 11 kg / cm2 of air is
blown, and all drop tests It was good.
[0069]
In Comparative Example 1, a film having a thickness of 6.5 μm was obtained by extruding
polyethylene naphthalate (tensile elastic modulus: 6000 MPa, crystalline resin) and stretching.
The tan δ at 20 ° C. was 0.039, and the glass transition temperature was 120 ° C. (see FIG. 5).
The thickness accuracy was ± 3%. The conditions for forming the film into a dome shape were
repeated at a cooling temperature of 120 ° C. after heat melting to 225 ° C., and the pitch time
was about 40 to 50 seconds. As a result of mounting this diaphragm on a speaker and evaluating
it, the f0 value was 550 Hz, the distortion at fh was 3000 Hz, and the distortion at 700 Hz was as
large as -20 dB. In the air blow test, the air was deformed with 4.2 kgf / cm 2 of air. Although
three samples were good in the drop test, deformation or breakage occurred in seven samples.
[0070]
In Comparative Example 2, a sheet of 9.5 μm was obtained by extruding an amorphous
polyetherimide resin (PEI, an amorphous resin having an elastic modulus of 3100 Mpa).
According to the viscoelastic measurement, tan δ at 20 ° C. was 0.019, and the glass transition
temperature was 215 ° C. (see FIG. 6). The accuracy of the thickness was ± 7%. The sheet was
formed into a dome at a heating temperature of 240 ° C. and a cooling temperature of 210 ° C.
The pitch time at that time was 13 to 17 seconds. When this speaker diaphragm was mounted on
a speaker and evaluated, f0 was 550 Hz, fh was 2300 Hz, distortion at 700 Hz was -20 dB, and
deformation occurred by air blowing at 9.5 kg / cm 2 in the air blow test. The drop test was
100% good.
[0071]
The productivity of the film and the diaphragm is shown in Table 1 and the vibration
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characteristics of the diaphragm are shown in Table 2 for Examples 1 to 7 and Comparative
Examples 1 and 2.
[0074]
As is apparent from Table 1, the embodiment is excellent in productivity at the time of molding,
even if f0 is designed to be lowered to 450 Hz. Further, as apparent from Table 2, in the example,
f0 is small and distortion is small even if the thickness is large compared to the comparative
example 1. The example has substantially the same diaphragm thickness as the comparative
example 2 but has a large fh and a small distortion. It is believed that this is because the film has
a low tensile modulus and a high tan δ.
[0075] In Example 8, 0.5 mol of trimellitic anhydride, 0.5 mol of cyclohexanedicarboxylic acid,
0.98 mol of isophorone diisocyanate, and 0.02 mol of potassium fluoride are charged into a
reaction vessel together with γ-butyrolactone, It adjusted to 50 weight%. The solution was
allowed to react for 2 hours at 120 ° C. with stirring, and then for another 4 hours at 190 ° C.
The solution was cooled to room temperature while being diluted to about 25% with N-methyl-2pyrrolidone, poured into water with stirring, reprecipitated, filtered, and dried with hot air at 90
° C. The logarithmic viscosity of the obtained polymer was 0.31 dl / g. In a container, 11.4 parts
by weight of this polymer, 1.1 parts by weight of carbon black ECP 600 JD, 43.8 parts by weight
of ethanol, 43.8 parts by weight of toluene, 100 parts by weight of 1 mmφ glass beads are
placed, and a paint shaker is used for 6 hours It disperse | distributed and obtained the antistatic
agent. The antistatic agent was coated on the film of 11 μm obtained in Example 1 with a coater
to a dry film thickness of 1 μm to obtain a film subjected to antistatic treatment. This film was
press-formed into a dome shape shown in FIG. 9 using a male and female mold as in Example 1,
to obtain a speaker diaphragm. In FIG. 9, 16 indicates an antistatic layer.
[0076] Example 9 is different from Example 1 in that 10 parts by weight of quaternary
ammonium chloride is added as an antistatic agent to 100 parts by weight of resin varnish (a
solution in which synthesized polyamideimide resin is dissolved in ethanol and toluene). A
speaker diaphragm was obtained in the same manner as in Example 1.
[0077] With respect to Examples 1, 8 and 9, the antistatic effect, the condition of the mold
surface at the time of molding, and the rate of molding failure are shown in Table 3. The surface
resistance was measured by applying 500 V for 10 seconds at 22 ° C. and 50% using a surface
high resistance meter HT210 manufactured by Mitsubishi Yuka.
11-05-2019
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[0078] As is clear from Table 3, by using a conductive agent that does not bleed out, such as
carbon black, as the antistatic agent, the antistatic property is improved and the workability is
improved.
[0079] According to the present invention, a loudspeaker diaphragm can be obtained which has
the following remarkable effects. By using a polyamide imide resin or a polyimide resin, it is
possible to obtain a non-crystalline and spreadable ductility, a modulus of elasticity, a
characteristic such as tan δ which is optimum for a speaker diaphragm. Moreover, since it is
soluble in a low boiling point solvent, it can be formed into a film by casting method, so that a
film with high film thickness accuracy can be obtained, and as a result, the yield of the speaker is
improved. It has become possible to obtain a high yield with a short pitch time and a
conventionally realized diaphragm in which the diameter of the dome portion is about 5 mmφ.
The diaphragm using the polyamideimide resin or polyimide resin of the present invention
satisfies all the required characteristics such as productivity, sound quality variation, impact
resistance, etc. even if f0 is reduced. Also, by using carbon black as an antistatic agent for the
polyamideimide resin and polyimide resin used in the speaker diaphragm of the present
invention, effects such as reduction of surface resistance and reduction of mold contamination
can be obtained, and the workability is improved. It has a remarkable effect. .
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