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JPH06293064

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This translation is machine-generated. It cannot be guaranteed that it is intelligible, accurate,
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DESCRIPTION JPH06293064
[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a
film of para-oriented aromatic polyamide, particularly to a representative poly-p-phenylene
terephthalamide (hereinafter referred to as "PPTA"). 1. Field of the Invention The present
invention relates to a molding method for heat-pressing a film into a predetermined shape and an
apparatus therefor, and relates to a film molding method and a molding apparatus capable of
efficiently molding with high quality.
[0002]
2. Description of the Related Art Since films made of para-oriented aromatic polyamides, in
particular PPTA films, are excellent in acoustic properties, we have previously proposed acoustic
signal system members molded with this PPTA film and a method for producing the same.
(Unexamined-Japanese-Patent No. 3-38200). As a first method, this molding method is a heat
press using a PPTA film having a tensile elongation of 100% in the gel state containing water as a
swelling agent of at least 50% or more, preferably 80% or more. A molding method of molding
and heat setting while clamping the above-mentioned film with the molding die, and a second
method, heat treatment unstretched to give a hard PPTA film in a state having a tensile
elongation of 40% or more This is a molding method in which heat and pressure molding is
performed by a heat press machine, and the vibration system members for sound are actually
mass-produced by this molding method.
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[0003]
The outline of the first method will be explained based on FIGS. 9 to 12 as follows: A gel-like film
Fg containing at least 50% or more, preferably 80% or more of water as a swelling agent is
heated to about 150 ° C. Clamp with molds 1u and 1b, heat from this state to 350 ° C or
higher, and the temperature of upper die 1u is 140 ° C to 150 ° C, and the temperature of
lower die 1b is around 150 ° C to 160 ° C. It is a method of cooling until it becomes, releasing
molds 1u and 1b, and removing a cast film.
[0004]
That is, first, the gel film Fg is disposed between the upper and lower molds 1 u and 1 b as
shown in the figure, and when the mold starts to descend, the heater block 2 heated to about
380 ° C. to 400 ° C. descends. The gel film Fg is clamped while the upper and lower molds 1 u
and 1 b are heated while in close contact with the back surfaces of the upper and lower molds 1
u and 1 b.
The temperature of the upper and lower molds 1 u and 1 b at the start of this clamp is 140 ° C.
to 150 ° C. Since the heater block 2 is heated to 380 ° C. to 400 ° C. after clamping the upper
and lower molds 1 u and 1 b, the temperature of the molds 1 u and 1 b starts to rise
immediately.
[0005]
As the temperature of the molds 1u and 1b rises, the water contained in the film Fg is
acceleratedly evaporated and discharged to the outside of the molds 1u and 1b, and the
temperature of the molds further rises to cause the upper and lower molds 1u and 1b to When
the film reaches a predetermined temperature (more than 350 ° C.), the film is heat-treated as a
result, so that a predetermined crystallization is performed to obtain a predetermined density of
the PPTA film and to express an original physical property value . However, even at a high
temperature of 350 ° C. or higher, the modulus of elasticity is lowered even for PPTA films.
[0006]
That is, the mold release at the high temperature may cause deformation of the molded product
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due to friction or the like at the time of demolding of the PPTA film molded with the molds 1 u
and 1 b. That is, it is preferable to lower the temperature of the film in order to recover the
elastic modulus of the PPTA film and to avoid the deformation due to the friction at the time of
demolding. Accordingly, with the molds 1u and 1b clamped, the heater block 2 is separated from
the back surfaces of the upper and lower molds 1u and 1b, and instead, as shown in FIG. 11, the
cooling block 2c slides and the upper and lower molds 1u The cooling air is blown out from the
holes provided in the cooling block 2c to cool the upper and lower molds 1u and 1b. Further,
when the upper and lower molds 1u and 1b are cooled to a predetermined temperature (140 °
C. to 150 ° C.), the upper and lower molds 1u and 1b are released as shown in FIG. The block 2c
returns to the predetermined position.
[0007]
The outline of the second method will be described based on FIG. 13 to FIG. 16. The unstretched
hard film Fh having a tensile elongation of 40% or more is a molding die 1u, 1b heated to about
350 ° C. or higher. After clamping for a predetermined time in this state, the mold is cooled to
about 80 ° C., and the mold is released to release the molded film.
[0008]
That is, the unstretched hard film Fh having a tensile elongation of 40% or more is disposed
between the upper and lower molds 1u and 1b as shown in the figure, and the heater block 2 is
in close contact with the back surface of the molds 1u and 1b. Then, clamp as shown in FIG. 14
with the molds 1 u and 1 b heated to about 350 ° C., and hold this state for a predetermined
time (10 to 30 seconds).
Furthermore, the temperature of the film is lowered in order to avoid the deformation due to
friction at the time of demolding as described above.
[0009]
That is, while the molds 1u and 1b are clamped, the heater block 2 is separated from the back
surfaces of the upper and lower molds 1u and 1b, and instead the cooling block 2c slides as
shown in FIG. The cooling air is blown out from the hole provided in the cooling block 2c to cool
the upper and lower molds 1u and 1b. When the upper and lower molds 1u and 1b are cooled to
around 80 ° C., the upper and lower molds 1u and 1b are released as shown in FIG. 15, and the
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molded film is released, and the heater block 2 and the cooling block 2c Return to position.
[0010]
A common point of these molding methods is that the molded film heated to 350 ° C. or higher
is cooled while being clamped in the upper and lower molds 1 u and 1 b. That is, as described
above, the PPTA film heated to 350 ° C. or higher has a lower elastic modulus than the normal
state, and when the mold is released immediately after the molding is completed, the film does
not have the strength to hold the molded state. It is easily deformed by friction with the mold at
the time of release and friction with the mold at the time of mold removal, so cooling to such an
extent that the film withstands the friction force generated at the time of mold release and film
removal. It is necessary to
[0011]
Therefore, in the first and second molding methods, heating to 350 ° C. and cooling to 160 ° C.
or cooling to around 80 ° C. are necessary conditions for the molding die, and this condition is
molding It is an issue to be solved to increase the cycle time. At present, the minimum molding
cycle time is about 5 minutes per cycle, and poor molding machine maintenance results in about
7 to 8 minutes of molding cycle time.
[0012]
Therefore, the present invention is made to solve the above-mentioned problems, and it is
possible to shorten the molding cycle time and to provide a film molding method and an
apparatus therefor which can obtain a molded product of excellent quality. The purpose is to
[0013]
[Means for Solving the Problems] In order to solve this problem, the film forming method of the
present invention is basically a forming method in which the steps are divided into primary
processing and secondary processing.
That is, the primary processing is a step of extracting water which is a swelling agent of the gel-
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like PPTA film (hereinafter referred to as a dehydration step). And secondary processing is a heat
treatment process for heat setting to develop the basic performance of the film. By dividing into
these two steps, the cooling time in the molding cycle can be eliminated.
[0014]
The first method of the film forming method of the present invention is to heat press the film
made of a substantially para-oriented aromatic polyamide having a tensile modulus of 600 Kg /
mm 2 or more, particularly a typical PPTA film thereof into a predetermined shape. In the
molding method for molding, in the first step, the swelling agent water is evaporated from the
PPTA film in a state of containing at least 50% or more, preferably 80% or more of water as a
swelling agent, and the predetermined density is not reached. A film is obtained in an amorphous
state and has an elongation of about 70%, and in the second step, the film is press-molded for a
predetermined time with a molding die heated to at least 330 ° C. or more, preferably 350 ° C.
or more A predetermined crystallization is carried out by applying to obtain a predetermined
density of the PPTA film and obtain a molded article by the PPTA film while expressing an
inherent physical property value A. In this case, it also includes a molding method in which the
film obtained in the first step is preheated at 200 ° C. or more and 300 ° C. or less after the
first step.
[0015]
The second method of the film molding method of the present invention is a molding method in
which the PPTA film is heat-pressure molded into a predetermined shape, and in the first step,
water as a swelling agent of at least 50% or more, preferably 80% or more Is molded by heat and
pressure for a predetermined time using a molding die heated to 220 ° C. or less, preferably
190 ° C. or less, and the second step includes the second method of the first method. In the
same manner as in the process, a PPTA film molded product is obtained.
[0016]
By dividing into the first step and the second step as described above, the cooling time in the
molding cycle can be eliminated.
However, the absence of the cooling step means that the mold is released immediately after the
heat treatment, that is, at a temperature of 350 ° C. or more, so the film is easily deformed as
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described above. Therefore, it was decided to attach an adsorption device or an exhaust device to
the male and female molds and release the film in close contact with one of the molds when the
molds are released.
[0017]
The film forming apparatus according to the present invention is an apparatus used to carry out
the first and second forming methods, which comprises a male mold and a female mold, and is
used in one of the molds when the mold is released. In order to bring the film into close contact,
an intake mechanism or an exhaust mechanism is provided for intake or exhaust via a hole or a
slit opened in the mold surface.
[0018]
By molding by the film molding method of the present invention using the molding apparatus of
the present invention, as a result, the cooling step can be omitted and the molding cycle time can
be significantly shortened.
In addition, since the film is released in close contact with the mold when the mold is opened,
there is no deformation due to friction or the like at the time of detachment even when the film is
in a high temperature state, and a molded article of excellent quality can be obtained. .
[0019]
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the film forming
method of the present invention will be described with reference to FIGS. 1 to 8 together with a
forming apparatus used for implementation. In the molding machine, as shown in FIGS. 1 and 2,
the molding dies 1u and 1b are attached to the heater block 2, and in the case of the present
embodiment, the upper die 1u is attached to the tip side of the pressing cylinder S, The lower
mold 1b is attached to the base B side of the press. The upper and lower molds 1u and 1b are
provided with fine holes 1h or slits as shown in the figure, and the holes 1h and the like are led
out of the mold as shown in FIG. The intake device 4 and the exhaust device 5 are connected.
[0020]
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The entire molding apparatus used in the first molding method includes a material supply
apparatus Ms, the molding apparatus described in FIGS. 1 and 2, a trimming press PT, and a
robot R as shown in the layout diagram of FIG. Of the three molding machines, two are the
primary molding machine P1 and the remaining one is the heat treatment molding machine PH.
The first molding method is a method of molding from a gel-like film containing at least 50% or
more, preferably 80% or more of a water as a swelling agent, but the material is 80% or more of
water as a swelling agent A gel-like film Fg containing about 150 μm thick (25 μm finished
thickness) and having a tensile elongation of about 100%, which is a material for preventing
evaporation of water which is a swelling agent of the film Fg It is installed in the shape of a roll
with specified width in the water tank of supply device Ms.
[0021]
The film Fg is sent out by a necessary amount from the material supply device Ms and cut to a
set dimension, then taken out by the robot arm Ra attached to the robot R, and the film Fg is
transported to the primary molding machine P1 and as shown in FIG. The upper mold 1u and the
lower mold 1b are disposed in the middle, and as shown in FIG. 3, the upper mold 1u and the
lower mold 1b are both press-formed while being heated to 200 ° C.
[0022]
Immediately after the pressing cylinder S is lowered and the switching valve 3 connected to the
upper and lower dies 1u and 1b is switched to the intake device 4 immediately before the film Fg
comes in contact with the upper die 1u, the intake device 4 is operated and clamp At the same
time as the start, the moisture adhering to the surface of the film Fg is suctioned, and while
pressing out the mold while further discharging it from the mold, the mold is lowered by
completely pressing the mold, the film Fg is along the mold In the clamped state, the film Fg is
converted into water vapor by the heat of the mold in the clamped state, and the hole 1h
provided in the mold 1u and 1b in about 1 to 2 minutes, slit Etc. through the intake device 4 to
the outside air.
[0023]
The upper and lower molds 1 u and 1 b are released in a state where the water contained in the
film Fg has been released to the outside of the film Fg.
However, in this state, although the film is molded into a predetermined shape, it is an
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amorphous state in which the moisture of the gel-like film Fg has just escaped, and is a molded
state with the hard-like film Ff.
Therefore, the hard film Ff in this state is in a state in which the physical property value of the
original PPTA is not expressed yet, so the molded product is, as a matter of course, in a state
where the predetermined strength is not obtained. Hereinafter, the molded product in this state
is referred to as a primary molded product h1.
[0024]
As described above, since the hard film Ff does not reach the predetermined strength, it is easy to
deform and release the mold in a state of easy deformation, the deformation due to the frictional
force at the time of mold release becomes more severe. Therefore, as shown in FIG. 4, the intake
device 4 of the upper die 1 u is stopped to prevent deformation, the switching valve 3 is switched
to the exhaust device 5 side, and the cylinder S is raised while operating the exhaust device 5.
Release the mold 1 u, 1 b.
[0025]
That is, since the primary molded product h1 in close contact with the upper mold 1u is peeled
off by the exhaust air from the upper mold 1u, and the intake device 4 of the lower mold 1b
remains in operation, the primary molded product h1 The upper mold 1u is released while being
adsorbed to the lower mold 1b, and after releasing the upper mold 1u, the surface of the film Ff
is slightly cooled in the atmosphere after the primary molded product h1 is released. Further, as
shown in FIG. 5, when the intake device 4 of the lower mold 1b is stopped and the valve 3 is
switched to the exhaust device 5 side and the exhaust device 5 is operated, the primary molded
product H1 is the lower mold 1b by air pressure. It exfoliates more and demolds.
[0026]
Next, the robot R transfers the primary molded product h1 to the molds 1u and 1b attached to
another heat treatment molding machine PH. The heat treatment molding machine PH basically
has the same structure and function as the primary molding machine P1, and the structures of
the upper and lower molds 1u and 1b are basically the same. The heating temperature of the
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upper mold 1 u is set to 380 ° C., the lower mold 1 b is set to 250 ° C., the above-mentioned
molded product is inserted into the mold and repressed for about 30 seconds to obtain the above
primary molded product h1. Heat fix.
[0027]
In this process, the hard film Ff in an amorphous state is subjected to heat treatment to perform
predetermined crystallization, obtain a predetermined density of the PPTA film, and express an
original physical property value. Therefore, a molded article having the original strength can be
obtained for the first time by forming a molded article in this state. Hereinafter, this molded
product is referred to as a heat-treated molded product hn.
[0028]
In the case of this press, when the primary molded product h1 is placed in the lower mold 1b, the
switching valve 3 connected to the lower mold 1b is switched to the intake apparatus 4 and at
the same time the intake apparatus 4 is operated to make the mold After the first molded
product is brought into close contact, the upper mold 1 u is lowered, and the upper and lower
molds 1 u and 1 b are completely clamped to perform heat treatment.
[0029]
When releasing the mold, the switching valve 3 of the upper mold 1u is switched to the exhaust
device 5 side, the cylinder S is raised while operating the exhaust device 5, and the mold is
released. Since the molded product in close contact with the upper mold 1u is peeled off by the
exhaust from the upper mold 1u, and since the intake device 4 of the lower mold 1b is still in
operation, the heat-treated molded article is used as the lower mold 1b. The upper mold 1 u is
released as it is adsorbed, and after releasing the upper mold 1 u, the film is rapidly cooled to
about 250 ° C. in the atmosphere.
Further, the intake device 4 of the lower mold 1b is stopped, the valve 3 is switched to the
exhaust device 5 side, and when the exhaust device 5 is operated, the heat-treated molded
product is released. The molded product in this state is transferred onto the trimming press PT
by the robot R, and the extra portion is trimmed to complete, for example, a diaphragm.
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[0030]
As a second molding method, PPTA gel-like film Fg having a thickness of about 140 μ,
containing at least 50% or more, preferably 80% or more of water as a swelling agent, is placed
in an oven at about 180 ° C. From the gel-like film Fg, water which is a swelling agent was
evaporated to obtain a non-oriented hard film Ff which did not reach a predetermined density
and was amorphous. The film Ff in this state has an elongation of about 70% and is a hard film Ff
25 μm thick.
[0031]
If this film is preheated by passing it through a 50 μ gap provided in the heating block 6 heated
to 250 ° C. to 330 ° C. as shown in FIG. After this preheating, the film Ff is drawn onto the
molding press molds 1u and 1b, and pressed for about 30 seconds with a molding mold in which
the upper mold 1u is heated to 380 ° C. and the lower mold 1b to 250 ° C. Heat setting was
performed at the same time. The upper and lower molds 1 u and 1 b are released in the same
manner as in the first molding method.
[0032]
In the third molding method, water which is a swelling agent is evaporated in an oven at about
180 ° C. in the same manner as in the second molding method described above, and it is
unstretched and does not reach a predetermined density and is amorphous hard. Film Ff was
obtained, and as shown in FIG. 8, it was drawn onto the molding press molds 1 u and 1 b without
preheating, and the upper mold 1 u was heated to 380 ° C. and the lower mold 1 b to 250 ° C.
The molding was pressed for about 30 seconds with a molding die and heat setting was
performed simultaneously with molding. The upper and lower molds 1 u and 1 b are released in
the same manner as in the first molding method.
[0033]
In any of the first to third molding methods, the valves 3 and the suction and discharge devices 4
and 5 attached to the upper and lower molds 1u and 1b are operated, but depending on various
conditions such as the shape of the molded product In some cases, mold removal may be
performed smoothly without operating the device, and in such a molding condition, these devices
3, 4 and 5 may not be operated, or these devices themselves Do not need
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[0034]
Each of the embodiments of the present invention is characterized in that the first molding
method is suitable for molding a deep-drawn and complex-shaped molded product, and the
second and third molding methods have shallow drawing. And a molding method suitable for
molding a molded product having a simpler shape.
However, from the point of view of the equipment surface at the film molding production site,
conversely, the third method may be the simplest equipment, and the equipment becomes more
complicated as the second and first molding methods become.
[0035]
When the speaker diaphragm is actually molded by the above molding method, one molding
cycle is about 5 minutes in the conventional molding method, but in the first molding method,
the molding cycle is 1 minute 30 seconds to 2 It is 30 minutes, which makes it possible to reduce
the molding cycle by 50% to 70%. Further, in the second and third molding methods, the molding
cycle was 30 seconds, and the molding cycle could be shortened by 90% as compared with the
conventional method. Therefore, it has become possible to improve productivity by about 2 to 10
times.
[0036]
According to the film molding method of the present invention, the time of one molding cycle can
be remarkably shortened as compared with the conventional molding method, and therefore, the
productivity can be significantly improved. In addition, there is no deformation or the like in the
molded product, and a product of excellent quality can be obtained. Moreover, according to the
molding apparatus which concerns on this invention, it can implement, without changing the
conventional apparatus significantly, and can implement the said molding method of this
invention easily and reliably.
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