JPH0833095

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DESCRIPTION JPH0833095
[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a
material of an edge of a diaphragm for a speaker used in various audio equipment and the like,
and a method of manufacturing the same.
[0002]
2. Description of the Related Art Conventionally, as an edge material of a speaker diaphragm
used for these, a woven fabric coated or impregnated with a resin such as SBR or NBR, or a
polyester type or polyether type soft. Polyurethane foam is often used.
[0003]
However, in the case of a woven fabric coated or impregnated with a resin such as SBR or NBR
described above, its moisture resistance and heat resistance are weak, and the amplitude linearity
with respect to the input is poor. There is a disadvantage that the decrease in frequency (fo) is
large.
Flexible polyurethane foams are better for this disadvantage. However, in the case of this flexible
polyurethane foam, the polyester-based flexible polyurethane foam is also weak in moisture
resistance, while in the case of the polyether-based flexible polyurethane foam, the moisture
resistance is strong but the weather resistance is weak, and There is a defect that it is easy to
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produce a pinhole from the manufacturing method. Also, generally, polyether-based flexible
polyurethane foams tend to be inferior in sound quality to those of polyester-based ones. It is
presumed that this is because reverse resonance tends to occur because the elasticity of the
material is large.
[0004]
SUMMARY OF THE INVENTION As a result of intensive studies on the above problems, the
present invention has both excellent weather resistance and moisture resistance, and can provide
sound quality comparable to that of polyester-based flexible polyurethane foam. The speaker
edge material of polyurethane foam was developed and it came to the present invention.
[0005]
[Summary of the Invention] That is, the gist of the present invention is a speaker of polyurethane
foam obtained by mixing a polyol used as a main raw material, an organic diisocyanate, a
foaming agent, a foam stabilizer, a catalyst and the like. An edge raw material, wherein 25% by
weight or more and 85% by weight or less of the polyol in the raw material is a compound
selected from the group consisting of a polyoxyalkylene polyol and a derivative thereof having a
hydroxyl group, an aromatic polycarboxylic acid anhydride The present invention relates to a
speaker edge material of polyurethane foam which is a polyether polyester polyol (Japanese
Patent Publication No. 48-10078) obtained by reacting a compound having a cyclic ether group
with a compound having a cyclic ether group.
[0006]
And, preferably, the above-mentioned polyether polyester polyol is a polyether polyester polyol
obtained by ring-opening polymerization of phthalic anhydride and propylene oxide in
polyoxypropylene triol.
[0007]
More preferably, the foam stabilizer is an active hydrogen-containing organosilicon compound.
Examples of the active hydrogen-containing group include a carboxyl group, a hydroxyl group,
an amino group and a methoxy group. Among these, a carboxyl group and a hydroxyl group are
preferable.
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As the structure of the active hydrogen-containing organosilicon compound, one having the
following structural formula is recommended.
[0008]
Embedded image m: an integer of 1 to 200 n: an integer of 1 to 50 R: a divalent organic group
containing polyoxyethylene or polyoxypropylene
[0009]
Further, it is preferable to improve the weatherability by adding carbon black of 0.4% by weight
or more to the whole polyol.
[0010]
In the present invention, it is necessary to use the above-mentioned polyether polyester polyol at
25 wt% or more and 85 wt% or less as the polyol. Polyether polyols obtained by ring-opening
polymerization of propylene oxide, ethylene oxide, etc. with polyhydroxyl compounds such as
trimethylolpropane, pentaerythritol, sorbitol, sucrose, ethylenediamine, diethylenetriamine,
diethylene glycol, dipropylene glycol using alkali catalysts And the viscosity is preferably 5,000
cp or less.
Further, polyether polyols, polyether ester polyols, graft polyols obtained by graft polymerization
of polystyrene and polyacrylonitrile can also be used.
[0011]
When the polyether polyester polyol is 25% by weight or less of the total polyol, it is difficult to
obtain the effects described later, and when it is 85% by weight or more, the viscosity becomes
higher than that of the foaming machine, and uniform mixing of the raw materials is possible. It
will be difficult.
[0012]
Usable polyisocyanates are aromatic polyisocyanates containing two or more isocyanate groups
in the same molecule, aliphatic polyisocyanates, or modified products thereof, specifically tri Diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, xylene diisocyanate and the
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like.
[0013]
Usually, carbon foam is added to the speaker edge material of polyurethane foam at the time of
foaming in order to make the weather resistance strong and make the color change
inconspicuous, but this is also effective in the present invention, and all the raw materials When
0.4% by weight or more of carbon black is added to the polyol, good weathering resistance is
obtained, and discoloration due to ultraviolet light is less noticeable.
[0014]
(1) A compound selected from the group consisting of a polyoxyalkylene polyol and a derivative
thereof having a hydroxyl group as a main raw material polyol, and a compound having an
aromatic polycarboxylic acid anhydride and a cyclic ether group By using 25 to 85% by weight of
the polyether polyester polyol, which is characterized by being obtained by reacting with each
other, and at the same time the heat resistance and moisture resistance are simultaneously
satisfied as compared to the speaker edge material of the conventional polyurethane foam. It can
be done.
[0015]
For example, in conventional polyester-based flexible polyurethane foams, the weather resistance
is relatively strong but the moisture resistance is weak.
On the other hand, in the conventional polyether-based flexible polyurethane foam, the moisture
resistance is strong but the weather resistance is weak.
On the other hand, the polyurethane foam using the above-mentioned polyether polyester polyol
as the raw material can obtain the same weather resistance as the polyester polyurethane foam
and the same moisture resistance as the polyether polyurethane due to the following reasons.
Weathering resistance: Due to the presence of the polyester portion in the raw polyol molecule,
the number of polyether bonds that are easily oxidized by ultraviolet light decreases, and thus
the weathering resistance increases.
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Moisture resistance: The moisture resistance of polyester-based polyurethane foam is weak
because the raw polyol molecule has an easily hydrolyzable aliphatic ester bond, but all the ester
bonds in the above polyether polyester polyol are aromatic esters. It is hard to be hydrolyzed.
[0016]
(2) In particular, as the above-mentioned polyether polyester polyol, polyether polyester polyol
obtained by ring-opening polymerization of phthalic anhydride and propylene oxide with
polyoxypropylene triol, and having an average molecular weight of 2,000 to 5,000, preferably
2,500. A flexible polyurethane foam having good mechanical properties can be easily foamed
using a conventional polyether-based flexible polyurethane foam formulation (foaming agent,
catalyst, surfactant, isocyanate, etc.) by using one of 〜4000. Is obtained.
[0017]
(3) The above-mentioned polyether polyester polyol has an extremely high viscosity because it
contains an aromatic ester bond in the molecule, and it is not easy to mix with other raw
materials when it is used alone when foaming a polyurethane foam. .
Therefore, it is preferable to use 85 wt% or less with respect to the total polyol, and to mix other
low viscosity polyols with the remaining 15 wt% or more.
As a commercial product, 3P56B (made by Takeda Pharmaceutical Co., Ltd.) etc. which mixed
beforehand the said polyether polyester polyol and general purpose polyether polyol for flexible
polyurethane foams of the molecular weight 3000 in 3: 1 ratio etc. exist, and it is good to use
these.
When the content of the above-mentioned polyether polyester polyol is 25% by weight or less
based on the total raw material polyol, the characteristics of the above-mentioned polyol can not
be utilized for the weather resistance and moisture resistance of the product polyurethane foam.
[0018]
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(4) The sound quality is further improved by using an active hydrogen-containing organosilicon
compound as a foam stabilizer. (5) The polyurethane foam speaker edge material manufactured
in this way has good sound quality and, in particular, has the characteristic that the sound in the
middle range is extended. Although the reason for this is not clear, the inventors speculate that
the aromatic ester molecules in the material make the material less likely to cause reverse
resonance because the energy loss inside the material is large.
[0019]
EXAMPLES Example 1 An average molecular weight of 3,000 obtained by ring-opening
polymerization of phthalic anhydride and propylene oxide with polyoxypropylene triol having an
average molecular weight of 2,000 of a glycerol-propylene oxide adduct: Hydroxyl 100 parts by
weight of a polyol in which a polyether polyester polyol having a valence of 56 and glycerinpropylene oxide polyoxypropylene triol (average molecular weight 3,000, hydroxyl number 56)
are mixed beforehand at a ratio of 75:25, and 33% dipropylene of triethylenediamine 0.3 part of
glycol solution, 0.3 part of stannas octoate, 1.0 part of general purpose silicone surfactant for
flexible polyurethane foam, 3.2 parts of water, 1.0 part of carbon black, and TDI (T-65) Mix
rapidly with 45 parts To obtain a re-urethane foam.
[0020]
Example 2 In the above Example 1, a carboxyl group-containing silicone surfactant (SF2914,
manufactured by Toray Dow Corning Silicone Co., Ltd.) was used instead of 1.0 part of the
general purpose silicone surfactant for flexible polyurethane foam. A polyurethane foam was
obtained with exactly the same formulation except that the same part was used.
[0021]
EXAMPLE 3 A polyoxypropylenetriol having an average molecular weight of 2,000 of a glycerolpropylene oxide adduct was obtained by ring-opening polymerization of phthalic anhydride and
propylene oxide with a poly of an average molecular weight of 3,000 and a hydroxyl value of 56.
100 parts by weight of a polyol in which an ether polyester polyol and a polyoxypropylenetriol
of glycerin-propylene oxide (average molecular weight 3000, hydroxyl value 56) were previously
mixed in a ratio of 50:50 by weight, and a 33% dipropylene glycol solution of triethylenediamine
0. 3 parts, stannas octoate 0.3 parts, carboxyl group-containing silicone surfactant (the above SF
2914) 1.0 part, water 3.2 parts, carbon black 1.0 part, and TDI (T-65) 45 parts Mixed rapidly
with Obtaining a urethane foam.
[0022]
Comparative Example 1 Polyoxypropylenetriol of Glycerine-Propylene Oxide Adduct
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Polyoxypropylenetriol having an average molecular weight of 2000, obtained by ring-opening
polymerization of phthalic anhydride and propylene oxide was a poly of an average molecular
weight of 3,000 and a hydroxyl value of 56. 100 parts by weight of a polyol in which an ether
polyester polyol and a polyoxypropylenetriol of glycerin-propylene oxide (average molecular
weight 3000, hydroxyl number 56) were previously mixed at a weight ratio of 20:80, and a 33%
dipropylene glycol solution of triethylenediamine 0. 3 parts, Stannath octoate 0.3 parts, 1.0 part
of general purpose silicone surfactant for flexible polyurethane foam, 3.2 parts of water, 1.0 part
of carbon black, and 45 parts of TDI (T-65) Rapidly mixed and polluted Give a foam.
[0023]
Comparative Example 2 100 parts by weight of a polyester polyol (average molecular weight
2200, hydroxyl number 60) obtained by polycondensation of adipic acid-diethylene glycoltrimethylolpropane and 3 parts of a general purpose silicone surfactant for flexible polyurethane,
N 2 parts of methyl morpholine, 0.3 parts of stannas octoate, 3.5 parts of water, 1 part of carbon
black, and 45 parts of TDI-80 are rapidly stirred to obtain a polyurethane foam.
[0024]
Comparative Example 3 100 parts by weight of polyoxypropylene triol (average molecular
weight 3,000, hydroxyl number 56) of glycerin-propylene oxide and 0.3 parts of a
triethylenediamine 33% dipropylene glycol solution, general purpose for flexible polyurethane
foam A polyurethane foam was prepared by rapidly mixing 1.5 parts of a silicone surfactant, 0.3
parts of Stanas octoate, 3 parts of water, 1 part of carbon black and 40 parts of TDI (T-80).
[0025]
In order to compare and evaluate the durability (weatherability and moisture resistance) of the
polyurethane foams prepared in Examples 1 to 3 and Comparative Examples 1 to 3, respectively,
they were cut into sheets of a thickness of 8 mm. Then, this was thermoformed at 200 ° C. for
30 seconds with a pneumatic press to form a sheet-like speaker edge material having a thickness
of 1 mm.
[0026]
The evaluation test method for the weather resistance of the material for the speaker edge was
carried out at a black panel temperature of 63 ° C. using a UV long-life fade meter (Suga Test
Instruments Co., Ltd., model FAL-5). .
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The sample for evaluation used the sheet-like thing of 100 mm x 60 mm in a fade meter, took it
out temporally, and measured the tensile strength by the tension test of JIS K6301.
[0027]
The moisture resistance was evaluated by measuring the durability in water vapor at 120 ° C.
using an autoclave.
A sample for evaluation was previously punched out in the shape of a dumbbell according to JIS
K6301-1, installed in an autoclave and taken out with time, and a tensile test according to JIS
K6301 was performed to measure the tensile strength.
[0028]
Further, the sound quality was evaluated by the following test.
Each foam material obtained in Examples 1 to 3 and Comparative Examples 1 to 3 is sliced into
sheets having a thickness of 7 mm, and formed into a roll edge having a thickness of 0.7 mm and
an outer diameter of 160 mm under conditions of 220 ° C. and 22 seconds. It was
thermoformed.
The speaker edge thus obtained is attached to a speaker (17PLO2A manufactured by National),
and the program source is reproduced using a standard sealed box and a drive amplifier defined
in JIS C5531-4.2 and 4.4. It was confirmed.
[0029]
In the sound quality confirmation by the sense of hearing, in Examples 2 and 3, a beautiful sound
quality was reproduced at a very stable volume.
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Although the sound quality of Example 1 was similar to that of Examples 2 and 3, the sound of
the midrange was weaker than that of Example 1.
Comparative Example 1 and 3 were inferior in sound quality to Example 1 and Comparative
Example 2, and the midrange sound was weak as well.
(Table 1 表示 display)
[0030]
At the same time, the output characteristics were measured based on JIS C5531. As a result, FIG.
1 shows a 500 to 1000 Hz portion where reverse resonance of the edge occurs in the output
characteristics of Example 2 and Comparative Examples 2 and 3. In Comparative Example 3, the
drop due to reverse resonance is the largest, and in Comparative Example 2 and Example 2, the
drop due to reverse resonance is the smallest. This indicates that the speaker edge of the second
embodiment has stabilized the output characteristics of the speaker.
[0031]
Table 1 shows the comparative evaluation results of the weather resistance, the moisture
resistance, and the sound quality by the audibility test.
[0032]
[Table 1]
[0033]
As apparent from the above Table 1 and above, it is also possible to use aromatic polycarboxylic
acids as compounds selected from the group consisting of polyoxyalkylene polyols and
derivatives thereof having hydroxyl groups as main raw material polyols. Compared with the
speaker edge material of the conventional polyurethane foam by using 25 to 85% by weight of
polyether polyester polyol which is obtained by reacting an anhydride and a compound having a
cyclic ether group with respect to the total polyol. Excellent heat resistance and moisture
resistance can be satisfied at the same time.
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Furthermore, the sound quality is improved by using an active hydrogen-containing
organosilicon compound as a foam stabilizer.
[0034]
Brief description of the drawings
[0035]
1 is a graph comparing the 500 to 1000 Hz portion where reverse resonance of the edge occurs
in the output characteristics of Example 2 and Comparative Examples 2 and 3.
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