JP2001009894A - Foamed sheet molding die and foamed sheet molding apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a foamed sheet molding die capable of enhancing expansion ratio and a foamed sheet molding apparatus capable of molding a foamed sheet having a smooth surface. SOLUTION: The resin flowing in a die is distributed in a manifold 2 to flow in the order of a pre-land part 3, a choke part 6, a sudden expansion part 7 and an almost parallel flow channel 8. Since a sudden pressure drop is generated in the choke part 6 near to a die outlet 5, a foaming start position becomes near to the die outlet and the shearing force receiving distance of a cellcontaining resin becomes short and the breakage of cells can be prevented. Foaming is rapidly advanced in the sudden expansion part 7 but the movement of the resin in a thickness direction C is corrected in the almost parallel flow channel 8 and the resin flows through the almost parallel flow channel 8 while filling this flow channel to flow out as a plate-shaped sheet. Since the growth of cells is almost completed at this time, the volumetric expansion of the sheet is reduced and no curtain wall is generated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a foam sheet molding die for molding a resin into a foam sheet having a predetermined shape, and a foam sheet molding apparatus used for a foam sheet molded by the foam sheet molding die. . INDUSTRIAL APPLICABILITY The present invention can be applied to molding of a foamed sheet of polypropylene, polyethylene, PET, nylon, polystyrene and the like.

[0002]

2. Description of the Related Art A schematic diagram of a conventional T-die for sheet extrusion is shown in FIGS. In a conventional general T-die, as shown in FIG.
Is supplied in the die width direction A by the manifold 102. In the pre-land portion 103 following the manifold 102, as shown in FIG. 18, the flow channel thickness is reduced, and the flow channel thickness is minimized in the lip land portion 104. After the resin pressure in the die reaches the maximum value at the extruder tip, the conduit 101 and the manifold 102
And the pressure is released from the pressure in the manifold to the atmospheric pressure in the lip land portion 104.

In a conventional T-die called a choke bar system, as shown in FIG. 20, a choke bar called a choke bar is provided from a pre-land portion to a land portion. , The same as a general T-die. For this reason, similarly to a general T-die, after the resin pressure in the die reaches a maximum value at the extruder tip, the conduit 1
01, the manifold 102, the pre-land portion 103, and the choke portion 121 gradually decrease, and the lip land portion 104 releases the manifold internal pressure to the atmospheric pressure.

[0004]

When a foamed sheet is formed by extrusion foaming with a conventional die, the lip tip 105
When the foam expands rapidly due to the release of air to the atmosphere, the volume expansion coefficient of the sheet immediately after flowing out of the die increases, and when the expansion is performed isotropically, the curtain wall phenomenon ( Corrugation) occurs. Therefore, unevenness occurs on the sheet surface,
When it was wound by a cooling roll (not shown) downstream of the die, it did not become a good product. Even in a conventional T-die called a choke bar method, the thickness of the land is the same as that of a general T-die, and the resin is released to the atmosphere immediately after the tip of the lip. Immediately after the sheet is discharged from the die, the volume expansion rate increases, and a curtain wall phenomenon (corrugation) occurs due to isotropic expansion.
Therefore, due to the unevenness of the sheet surface, a non-defective product was not obtained when wound by a cooling roll (not shown). Further, in other prior arts, for example, JP-A-8-142156,
Although a specific opening angle and a specific length of taper portion are provided at the end of the lip land portion, the resin pressure in the die is not sufficiently reduced, so that the bubble diameter tends to increase and the expansion ratio does not increase. There was a problem. The present invention has been made in view of such circumstances, and an object of the present invention is to provide a foam sheet forming die capable of improving the expansion ratio. Also,
An object of the present invention is to provide a foam sheet forming apparatus capable of forming a foam sheet having a smooth surface.

[0005]

SUMMARY OF THE INVENTION A foam sheet forming die according to the present invention has been made to solve the above-mentioned problem, and is provided on a land portion from a manifold for distributing resin in a width direction of a flow passage to a die lip. A choke portion whose flow channel thickness is narrowest than the other portion, and a substantially parallel flow channel located downstream of the choke portion and having a flow channel thickness greater than that of the choke portion. The chalk section was connected to the rapid expansion section. By arranging the choke portion, the rapidly expanding portion, and the substantially parallel flow path in this manner, the pressure is released to approximately the atmospheric pressure from the suddenly expanding portion to the substantially parallel flow path, thereby causing rapid bubbling during this time. It is possible to form a smooth foam sheet by making the particle size of the bubbles fine and uniform, improving the expansion ratio, preventing curtain wall (corrugation), and forming a smooth foam sheet. The substantially parallel portion gives the expanded resin time for stress relaxation, and enables stable molding of a smooth sheet.

The die in the present invention refers to a die for extruding a material into a shape requiring a material in extrusion, and there are dies having various shapes and structures according to the purpose of use. Typical examples include a manifold die, a blow molding die, a ring die, a coat hanger die, a T-die, a film die, a tubing die, a screw die, a rotary die, and the like. The channel thickness in the present invention means a dimension of a channel in a die corresponding to a thickness direction of a foamed sheet to be formed. The term “substantially parallel flow path” in the present invention is a concept including a parallel flow path, and refers to a case where the flow path is not slightly parallel due to a requirement in manufacturing or the like. The expansion ratio in the present specification is a numerical value obtained by dividing the density of the polypropylene resin by the apparent density of the foam, and indicates the degree of lightness. In addition, the choke section from the manifold (2)
The preland portion (3) and the choke portion (6) reaching (6) need not be parallel flow paths.

[0007] The choke portion has a throat channel thickness of 1.
5 mm (mm) or less, the sharply enlarged portion has an opening angle θ of 20 degrees to 180 degrees, and the substantially parallel flow channel has a flow channel thickness of 2.5 times or more of the choke portion. It is preferable to configure the following. In addition, it is desirable that the land portion located on the upstream side of the choke portion has a channel thickness of 2.5 mm (mm) or more. In particular, the flow path thickness of the preland portion and the choke portion is preferably set so that the resin pressure in the manifold is about 80 kg / cm ² . The joint between the choke portion and the suddenly enlarged portion and the joint between the suddenly enlarged portion and the substantially parallel flow path may have a smooth R shape or a chamfered shape. In the case of a highly viscous fluid such as a molten resin, there is no separation of the flow from the wall surface at the corners, and the pressure gradient is determined by the cross-sectional area of the flow channel perpendicular to the flow direction. Therefore, as shown in FIG. The central axes in the thickness direction of the enlarged portion and the substantially parallel flow channel need not coincide. That is, the opening angle ∠ZxZ 'in FIG. 2 does not have to be symmetrical with respect to the center axis like the opening angle θ in FIG. 2B, and may be asymmetric.

The choke portion is preferably provided near the die exit in the land portion. With such a configuration, a sudden pressure drop occurs at a position near the die outlet, foaming starts, and the pressure is released to approximately atmospheric pressure from the rapid expansion portion to the substantially parallel flow path, during which time It can be foamed rapidly. The rapid pressure drop causes the resin to grow rapidly with bubbles, and generates fine bubbles having a uniform particle size due to the elongational viscosity characteristic of the resin that rises with time. Further, the distance to which the resin containing air bubbles is subjected to the shearing force is reduced, so that the air bubbles are prevented from being broken and the expansion ratio is improved.

The thickness of the choke portion and the thickness of the substantially parallel flow channel may be variable. With such a configuration, it is possible to cope with a wide range of production amounts, resin viscosity, and expansion ratio.

[0010] A temperature control mechanism may be arranged near one or both of the choke and the substantially parallel flow path. When the resin to be foamed is polypropylene, the wall surface temperature in the vicinity of the substantially parallel flow path is desirably 110 to 200 degrees Celsius. With this configuration, the resin temperature in the vicinity of the surface layer is reduced, the gas diffusion coefficient of the resin near the surface layer is reduced, and the dissipation of gas in the bubbles due to diffusion can be reduced. The expansion ratio can be improved. The temperature control mechanism is for suppressing the heat generation of the resin near the flow path wall and reducing the resin temperature.Piping is provided in the vicinity of the flow path substantially parallel to the choke portion, and a lower temperature fluid is provided in the pipe. For example, room temperature air may be supplied. As a means for supplying room temperature air, it is sufficient to use a commonly used device.

[0011] The choke portion may be composed of pores arranged at predetermined intervals in the flow channel width direction. With this configuration, the resin once distributed in the fine pores of the choke portion expands and merges isotropically on the downstream side of the fine pores, and is filled in the substantially parallel flow path to fill the plate-like sheet. Are formed, and a curtain wall (corrugation) can be prevented. The term “isotropic” as used herein means that its physical properties do not differ depending on the vertical, horizontal, etc. direction.

The pores may be arranged such that adjacent pores are located at different positions in the flow channel thickness direction. With this configuration, a space (expansion space) for the resin coming out of the narrow tube to expand not only in the thickness direction of the flow path but also in the width direction of the flow path is secured. The natural expansion can be performed more naturally, unnecessary correction can be eliminated, and the expansion ratio can be improved.

The above-mentioned pores may be constituted by a combination of irregularities provided on two members, respectively, and the interval between the two members may be variable. Specifically, the following may be performed. That is, the choke portion includes a first member in which longitudinally extending grooves are regularly formed and the first member.
And a second member formed with a crest corresponding to the groove of the member, wherein the pores of the choke are formed such that the groove of the first member and the crest of the second member are mutually connected. The first member and the second member are configured to be engaged with each other so that the member interval is variable in an engaged state of the first member and the second member. Further, the choke portion has two members having saw-tooth portions each having a substantially linear slope continuous with each other. The two members are shifted from each other in the flow path direction, and the one on the upstream side of the flow path. The downstream end face of the flow path in the member and the upstream end face of the flow path of the other member are arranged so that the saw-toothed portion communicates with the other member. The distance between the two members is variable. With this configuration, the cross-sectional area of the flow path can be changed by changing the interval between members, so that the pressure gradient can be changed (pressure loss can be changed), and the production amount can be adjusted widely. And the range of operation for resins having different viscosities is expanded. Further, the flow rate can be adjusted in the flow channel width (die width) direction, and the uniformity of the sheet thickness of the flow channel width is improved. That is, while improving the expansion ratio, a wide range of production,
Molding is possible with respect to resin viscosity and expansion ratio.

In the foam sheet forming apparatus according to the present invention, a feed means is provided downstream of the die for forming a foam sheet to feed the foam sheet to the downstream side at a predetermined speed in contact with the front and back surfaces of the foam sheet. The feeding means cools the foam sheet. As the feeding means, a temperature-controlled roll rotating at a predetermined speed is opposed to the temperature-controlled belt, for example, a metal belt rotating at a predetermined speed, such as a metal belt, or a temperature-controlled temperature rotating at a predetermined speed. Alternatively, the rolls may be arranged so as to be different from each other in the outflow direction. Further, the interval between the front and back feeding means may be variable. The temperature of the feeding means may be adjusted by using a commonly used device. In this case, the roll may be a single-stage or a plurality of stages.

[0015]

Next, an embodiment of a foam sheet forming die according to the present invention will be described with reference to the drawings. A first embodiment will be described with reference to FIGS. The T-die of the present embodiment is configured as follows. In the land from manifold 2 to die lip,
A preland portion 3 and a choke portion 6 are provided. The pre-land portion 3 is located in the upstream portion of the land, and the flow channel thickness is 2.5
mm (millimeter) or more. The choke 6 has a throat thickness of 1.5 mm (millimeter) or less and a length of 30 mm. Immediately downstream of the choke 6, a rapid expansion section 7 and a substantially parallel flow path 8 following the section 7 are provided. The sharply expanding portion 7 has an opening angle θ of 20 degrees to 180 degrees. The flow path thickness of the substantially parallel flow path 8 is 2.5 times or more of the choke portion 6. The choke portion 6 and the rapid expansion portion 7 are connected by a corner portion 9, and the rapid expansion portion 7 and the substantially parallel flow path 8 are connected by a corner portion 9 ′. The corner portion 9 and the corner portion 9 ′ may be smoothly rounded or chamfered. The chalk part 6
It is provided near the die outlet 5.

The resin that has flowed into the die is distributed by the manifold 2 and flows in the order of the preland portion 3, the choke portion 6, the rapid expansion portion 7, and the substantially parallel flow channel 8. Since the thickness of the flow path of the choke portion 6 is smaller than that of the other portions, as shown in FIG.
A sharp pressure drop occurs at the choke 6 near the die outlet 5. Therefore, the foaming start position L1 at which the foaming pressure becomes equal to or lower than the foaming pressure.
Is closer to the die outlet 5 and the distance L to which the resin containing air bubbles is subjected to the shearing force is shortened, so that the bubbles can be prevented from breaking.
Further, the rapid pressure drop causes the resin to rapidly grow bubbles, and generates uniform and fine bubbles having a particle size due to the elongational viscosity characteristic of the resin which rises with time. Also,
In the substantially parallel flow channel 8, the pressure loss is small due to the large flow channel thickness, and the pressure is approximately atmospheric pressure. For this reason, foaming progresses rapidly in the rapid expansion section 7. Since the foaming is isotropic, a curtain wall tends to occur in the suddenly expanding portion 7, but the expansion in the width direction is reduced due to the rapid expansion in the thickness direction. The movement is corrected, the inside of the substantially parallel flow path 8 is filled, flows, and flows out as a plate-like sheet. When flowing out of the die from the substantially parallel flow path 8, the substantially parallel flow path 8
Since the growth of bubbles is almost finished in the inside, the volume expansion of the sheet is small, and no curtain wall is generated.

Next, a second embodiment will be described with reference to FIGS. In this embodiment, as shown in FIG. 4, the basic configuration is the same as that of the first embodiment.
As shown in (1), a choke portion flow path thickness variable bar 21 and a die lip variable bar 22 are added to the configuration of the first embodiment, so that the choke portion flow channel thickness and the substantially parallel flow channel thickness can be changed. It was made. By making the thickness of the flow path in the choke portion variable, the pressure gradient in the die can be further changed, the production amount can be adjusted widely, and the range in which resins having different viscosities can be operated is widened. Further, the flow rate in the die width direction A can be adjusted, and the sheet thickness uniformity in the die width direction A can be improved. In addition, since the thickness of the substantially parallel flow path can be changed, it is possible to cope with molding with a wide expansion ratio.

Next, a third embodiment will be described with reference to FIGS. In the present embodiment, as shown in FIG. 6, the basic configuration is the same as that of the first embodiment.
As shown in (1), a temperature control mechanism is additionally arranged near the choke portion flow path and the substantially parallel flow path in the configuration of the first embodiment. That is, an air cooling pipe 31 is arranged near the choke section 6 and the substantially parallel flow path 8, and is cooled by flowing normal-temperature air through the pipe to suppress heat generation near the choke section 6 and the substantially parallel flow path 8. I have. As a means for supplying room temperature air, it is sufficient to use a commonly used device. Since excessive heat generation of the resin in the choke portion 6 and the substantially parallel flow channel portion 8 can be suppressed, the dissipation of gas in bubbles due to the breaking and diffusion of bubbles can be reduced, and the expansion ratio can be improved. it can.

Next, a fourth embodiment will be described with reference to FIGS. In this embodiment, as shown in FIG. 8, the basic configuration is the same as that of the first embodiment.
As shown in FIG. 7, thin tubes 41 arranged at intervals in the die width direction A are arranged in the choke portion 6 in the configuration of the first embodiment. The resin that has flowed into the die is distributed by the manifold 2, and the preland portion 3, the choke portion 6, the rapid expansion portion 7,
It flows in the order of the substantially parallel flow path 8. Since the flow path thickness of the choke portion 6 is smaller than other portions, a sharp pressure drop occurs in the choke portion 6 near the die outlet 5 as shown in FIG. For this reason, the foaming start position L1 at which the foaming pressure is lower than the foaming pressure is close to the die outlet 5, the amount of the resin containing the bubbles that receives the shearing force is reduced, and the foaming can be prevented. Further, in the substantially parallel flow channel 8, the pressure loss is small because the flow channel thickness is large, and the pressure becomes substantially the atmospheric pressure. For this reason, foaming proceeds rapidly in the rapid expansion section 7. Although foaming is isotropic, the resin which has exited the narrow tube 41 of the choke portion 6 naturally expands isotropically because expansion space is secured not only in the thickness direction C but also in the die width direction A. Then, the resin from each of the thin tubes 41 merges and fills in the substantially parallel flow channel 8 to flow out as a plate-like sheet. Since there is no excessive correction, the expansion ratio can be improved.

Next, a fifth embodiment will be described with reference to FIGS. In the present embodiment, as shown in FIGS. 10 and 11, the basic configuration is the same as that of the fourth embodiment. However, as shown in FIG. The comb-shaped flow paths 51 and 52 have a structure in which they mesh with each other, and one of the comb-shaped flow paths 52 is movable, or, as shown in FIG. 13, a wavy (shape having a surface that bends in a substantially straight line). Wavy channel 5 with
The projections 4 and 55 are arranged so as to overlap with each other, and one of the wavy channels 55 is movable. As shown in FIG. 12B, the thin tubes 53 are arranged such that adjacent thin tubes are located at mutually different positions in the flow channel width direction. In addition, the thin tubes 53 and 56 can have a variable channel cross-sectional area. As shown in FIGS. 10 and 11, the resin that has flowed into the die is distributed by the manifold 2, and flows in the order of the preland portion 3, the choke portion 6, the rapid expansion portion 7, and the substantially parallel flow channel 8. Since the flow path thickness of the choke portion 6 is smaller than that of the other portions, the choke portion 6 close to the die outlet 5 as shown in FIG.
Causes a rapid pressure drop. For this reason, the foaming start position L1 at which the foaming pressure is lower than the foaming pressure is closer to the die outlet 5, and the distance to which the resin containing the bubbles is subjected to the shearing force is shortened, so that the foaming can be prevented. Further, in the substantially parallel flow channel 8, the pressure loss is small because the flow channel thickness is large, and the pressure becomes substantially the atmospheric pressure. For this reason, foaming proceeds rapidly in the rapid expansion section 7. Although the foaming is isotropic, the resin that has exited the thin tubes 53 and 56 formed by the engagement of the choke portions 6 has an expansion space secured not only in the thickness direction C but also in the die width direction A. The resin expands naturally and isotropically, and the resin from each of the small tubes 53 and 56 merges and fills in the substantially parallel flow channel 8 to flow out as a plate-like sheet. Since there is no unreasonable correction, the expansion ratio can be improved. Further, the thin tubes 53 and 56 formed by the meshing are connected to the movable portion (the comb-like channel 52 or the wavy channel 5).
By moving 5), the cross-sectional area of the flow path can be changed and the pressure gradient can be changed, so that the production amount can be adjusted widely and the range of operation for resins having different viscosities is expanded. Further, the flow rate can be adjusted in the die width direction A, and the sheet thickness uniformity in the die width direction A is improved.

Next, an embodiment of a foam sheet forming apparatus according to the present invention will be described with reference to FIGS. In the present embodiment, as the foam sheet forming apparatus of the foam sheet forming die (T die) in the above-described first to fifth embodiments, a temperature-controlled single-stage or multiple-stage opposed roll 61 (see FIG. 14) Or a temperature-adjusted opposed metal belt 62 (see FIG. 15), or a roll 63 (see FIG. 16) in which a temperature-adjusted single-stage or multiple-stage foam sheet 64 alternately contacts. Roll 61,
The peripheral speed of the metal belt 63 or the metal belt 62 is in a range of 1.1 to 5 times the resin outflow speed of the T-die. In FIGS. 14 and 16, three rolls are used, but the present invention is not limited to this, and other numbers of rolls may be used. When the resin to be foamed is polypropylene, the temperature of the cooling roll is desirably 40 to 160 degrees Celsius. By cooling and flattening the surface with the foam sheet sandwiched between the rolls 61 and 63 and the metal belt 62 described above, a foam sheet 64 with a small expansion ratio and a high foaming ratio can be obtained. Roll 6 rotating at a speed slightly higher than the resin outflow speed of the T-die
1, 63 or the metal belt 62
Draw is applied to the foam sheet 64 that has exited the die, and the flatness of the surface of the foam sheet 64 can be improved. Also,
As shown in FIG. 16, by using the rolls 63 in which the foamed sheets 64 alternately contact each other, the foamed sheets 64 can be easily cooled without being crushed. Further, by making the distance between the rolls 61 and 63 and the metal sheet 62 sandwiching the foamed sheet variable, it is possible to cope with a wide range of molding conditions. Further, a cooling roll at room temperature or lower may be provided downstream of the rolls 61 and 63 for cooling the foamed sheet. As a means for adjusting the temperature, a device generally used may be used.

[0022]

The foam sheet forming die according to the present invention is
In the land portion from the manifold to the die lip that distributes the resin in the flow channel width direction, the choke portion where the flow channel thickness is the narrowest than the other portion, and the flow channel thickness that is located downstream and larger than the choke portion Since the substantially parallel flow path having the following is provided, and the substantially parallel flow path and the choke portion are connected to each other at the rapid expansion portion, the particle diameter of generated bubbles can be made fine and uniform, and the expansion ratio can be improved. In addition, a curtain wall (corrugation) can be prevented, and a smooth foam sheet can be formed.

If the choke portion is provided near the die outlet in the land portion, a sudden pressure drop occurs near the die outlet and foaming starts, so that the foaming start position becomes closer to the die outlet and breaks. Bubbles can be prevented. Further, due to the rapid pressure drop, it is possible to promote fine and uniform particle size of generated bubbles.

If the thickness of the choke portion and the thickness of the substantially parallel flow channel are made variable, a wide range of production, resin viscosity, and expansion ratio can be achieved, and versatility can be improved.

When a temperature control mechanism is arranged near one or both of the choke and the substantially parallel flow path,
Dissipation of gas in the bubbles due to bubble breaking and diffusion can be reduced, and the expansion ratio can be improved.

When the choke portion is formed of pores arranged at predetermined intervals in the flow channel width direction, the expansion ratio can be improved.

The above-mentioned pores are arranged such that adjacent pores are located at different positions in the flow channel thickness direction, so that a more natural isotropic expansion is performed, whereby a curtain wall (corrugation) is formed. Can be prevented, and the expansion ratio can be improved.

The above-mentioned pores are constituted by a combination of irregularities provided on the two members, respectively. If the distance between the two members is made variable, the production amount, resin viscosity,
A wide range of molding can be performed for the expansion ratio.

In the foamed sheet molding apparatus according to the present invention, a feeding means is provided downstream of the foamed sheet molding die to contact the front and back surfaces of the foamed sheet and feed the foamed sheet downstream at a predetermined speed. Since the feeding means cools the foamed sheet, both the front and back surfaces are cooled and flattened, so that a foamed sheet having a smooth surface with few irregularities can be obtained.

Further, the feeding means may be constituted by a plurality of opposed rolls of which temperature is controlled, or may be constituted by opposed metal belts of which temperature is controlled, or may be constituted by a plurality of stages of controlled temperature. If the rolls are arranged so that the foamed sheets alternately contact each other in the flow direction, the above-described effects can be further obtained.

Further, if the distance between the front and back sides of the feeding means can be adjusted, the above-described effect can be obtained, and a wide range of molding conditions can be accommodated.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view in a flow channel width direction of a foam sheet forming die according to a first embodiment of the present invention.

2A is a sectional view taken along line II-II in FIG.
(B) is a partial sectional view showing the opening angle θ in (a).

FIG. 3 is a pressure distribution diagram in a flow direction in a die according to the present invention;
The vertical axis indicates the pressure P in the die, and the horizontal axis indicates the position in the die.

FIG. 4 is a cross-sectional view in a flow channel width direction of a foam sheet forming die according to a second embodiment of the present invention.

FIG. 5 is a sectional view taken along line VV in FIG. 4;

FIG. 6 is a cross-sectional view in a flow channel width direction of a foam sheet forming die according to a third embodiment of the present invention.

FIG. 7 is a sectional view taken along line VII-VII in FIG. 6;

FIG. 8 is a cross-sectional view in a flow channel width direction of a foam sheet forming die according to a fourth embodiment of the present invention.

9 is a sectional view taken along line IX-IX in FIG.

FIG. 10 is a cross-sectional view in a flow channel width direction of a foam sheet forming die according to a fifth embodiment of the present invention.

FIG. 11 is a sectional view taken along line XI-XI in FIG. 10;

12A is an enlarged cross-sectional view of a choke portion of FIG. 11, and FIG. 12B is a partial plan view of FIG.

13A and 13B are modified examples of the foam sheet forming die according to the fifth embodiment of the present invention. FIG. 13A is an enlarged cross-sectional view of a choke portion in FIG. 11, and FIG. FIG.

FIG. 14 is a cross-sectional view illustrating a state in which the foam sheet forming apparatus according to one embodiment of the present invention is disposed downstream of the foam sheet forming die.

FIG. 15 is a cross-sectional view when a modified example of the foam sheet forming apparatus of FIG. 14 is arranged.

FIG. 16 is a cross-sectional view when another modified example of the foam sheet forming apparatus of FIG. 14 is arranged.

FIG. 17 is a cross-sectional view in the flow channel width direction of a conventional sheet and film forming die.

FIG. 18 is a sectional view taken along line XVIII-XVIII in FIG. 17;

FIG. 19 is a conventional pressure distribution diagram in the flow direction in a die;
The vertical axis indicates the pressure P in the die, and the horizontal axis indicates the position in the die.

FIG. 20 is a cross-sectional view in the flow channel width direction of a conventional choke bar type sheet and film forming die.

21 is a sectional view taken along line XXI-XXI in FIG.

FIG. 22 is a conventional pressure distribution diagram in the flow direction in a die,
The vertical axis indicates the pressure P in the die, and the horizontal axis indicates the position in the die.

FIG. 23 is a partially enlarged cross-sectional view of a choke portion, a rapidly expanding portion, and a flow direction of a substantially parallel flow channel of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Conduit 2 Manifold 3 Preland part 5 Die outlet 6 Choke part 7 Rapid expansion part 8 Substantially parallel flow path 9 Corner part 21 Choke part flow path thickness variable bar 22 Die lip variable bar 31 Air cooling pipe 41, 53, 56 Narrow pipe 51 52 Comb flow path 54, 55 Wavy flow path 61, 63 Roll 62 Metal belt 64 Foam sheet A Die width direction B Flow direction C Thickness direction L Distance L1 Foaming start position

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hidetoshi Kitajima 1 Nagoya Laboratory, Iwazuka-cho, Nakamura-ku, Nagoya City, Aichi Prefecture Inside the Nagoya Research Laboratory, Mitsubishi Heavy Industries, Ltd. (72) Inventor Masahiro Tsuboi Iwazuka-cho, Nakamura-ku, Nagoya-shi, Aichi Prefecture No. 1 Takamichi F-term in Nagoya Machinery Works, Mitsubishi Heavy Industries, Ltd. 4F207 AG01 AG20 AR06 AR12 KA01 KA11 KF14 KK52 KK64 KK65 KK74 KL57 KL62 KL63 KL76 KL83 KM15 KM16

Claims (12)

[Claims] 1. A choke section having a smaller flow path thickness than another section and a flow path located downstream of the choke section at a land portion from a manifold to a die lip for distributing resin in a flow channel width direction. A foam sheet molding die, comprising: a substantially parallel flow path having a path thickness, and the substantially parallel flow path and the choke portion are connected to each other at a rapidly expanding portion. 2. The foam sheet forming die according to claim 1, wherein the choke portion is provided near the die outlet in the land portion. 3. The flow path thickness of the choke portion and the flow path of the substantially parallel flow path are each variable.
Or the die for molding a foamed sheet according to 2. 4. The foam sheet forming die according to claim 1, wherein a temperature control mechanism is disposed near at least one of the choke portion and the substantially parallel flow path. 5. The foam sheet forming die according to claim 1, wherein the choke portion is formed of pores arranged at predetermined intervals in a flow channel width direction. 6. The foam sheet forming die according to claim 5, wherein the fine holes are arranged such that adjacent fine holes are located at positions different from each other in a flow channel thickness direction. 7. The foam sheet molding method according to claim 5, wherein the pores are formed by a combination of concave and convex shapes respectively provided on two members, and a distance between the two members is variable. Die. 8. A feeding means for abutting the front and back surfaces of the foam sheet on the downstream side of the foam sheet forming die according to any one of claims 1 to 7, and sending the foam sheet to the downstream side at a predetermined speed. Wherein the feeding means cools the foamed sheet. 9. The foam sheet forming apparatus according to claim 8, wherein the feeding means is a plurality of opposed rolls whose temperature is adjusted. 10. The foam sheet forming apparatus according to claim 8, wherein the feeding means is a metal belt whose temperature is opposed to the metal belt. 11. The foamed sheet forming apparatus according to claim 8, wherein the feeding means is a plurality of stages of temperature-controlled rolls, and the foamed sheets are arranged to alternately contact in the flow direction. . 12. The apparatus according to claim 8, wherein the distance between the front and back of the feeding means is adjustable.
Item 7. The foamed sheet molding apparatus according to item 1.