JP2015098120A - Extrusion molding apparatus and method for manufacturing thermoplastic elastomer molded article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an extrusion molding apparatus capable of giving high dimensional accuracy even when a thermoplastic elastomer that easily deforms by friction is used.SOLUTION: A shape adjusting machine 4, which is arranged between an extruder 2 that heats and extrudes a thermoplastic elastomer 10 and a take-up machine 3 that takes up the thermoplastic elastomer 10, includes a water tank 40 filled with cooling water W. A side wall 42 segmenting the water tank 40 is provided with an inlet 45a comprising a through hole for introducing the thermoplastic elastomer 10 into the water tank 40 and with an outlet 45b comprising a through hole for ejecting the thermoplastic elastomer 10 from the water tank 40. An aperture of the inlet 45a is larger than an outer diameter of the thermoplastic elastomer 10 after extruded from the extruder 2 and immediately before entering the inlet. A water level of the cooling water W is higher than upper ends of the inlet 45a and the outlet 45b.

Description

  The present invention relates to an extrusion molding apparatus and a method for producing a thermoplastic elastomer molded article.

  Conventionally, a paper feed mechanism such as an image forming apparatus uses a paper feed roller and a transport roller made of a thermoplastic elastomer. Such a sheet feeding roller and a conveying roller are required to have high accuracy in roundness, inner diameter, and outer diameter in order to convey a recording sheet or the like to the image forming unit with accurate timing and speed.

  The paper feed roller and the transport roller have, for example, a tubular thermoplastic elastomer as a base material. In general, in an extrusion molding apparatus that molds a tubular thermoplastic elastomer, a cooling water tank, a take-up machine, a cutting machine, and the like are sequentially arranged downstream from the extruder.

  The synthetic resin material heated and melted by the extruder is molded to have a predetermined cross-sectional shape when passing through a die and a mandrel at the exit of the extruder, and continuously extruded in a substantially horizontal direction. The high-temperature tubular molded product extruded from the extruder is cooled and cured when it passes through the cooling water in the water tank disposed between the extruder and the take-up machine while being taken up by the take-up machine. . Thereafter, the cured tubular molded product is cut by a cutting machine to obtain a paper feed roller or a transport roller as a product.

  In addition to the water pressure, the tubular molded product passing through the water tank is affected by the horizontal tension by the take-up machine and the vertical gravity. When these resultant forces are increased, the tube is crushed and the cross-sectional shape of the tube is flattened.

  Therefore, a vacuum cooling water tank using a sizing die is used in an extrusion molding apparatus for a tubular molded product that requires high dimensional accuracy. The sizing die has a through hole having a predetermined diameter and is attached to the inlet of the water tank. The tube is attracted to the through hole of the sizing die due to a pressure difference generated inside and outside the tubular molded product, and the outer dimension of the tube is regulated by the sizing die.

  As a technique for using a sizing die and a vacuum cooling water tank in combination, for example, in Patent Document 1 below, the atmospheric pressure in the cooling water tank is controlled by a feedback-controlled vacuum pump in order to keep the outer dimension of the cylindrical molded product at a desired value. An adjusting extrusion method is disclosed. In this extrusion molding method, a vacuum zone is provided inside the sizing die, and the outer surface of the molded product is brought into close contact with the through hole of the sizing die by the negative pressure state of the vacuum zone, so that the outer surface of the molded product is smoothly molded.

  In the following Patent Document 2, in order to form a thermoplastic polyimide tube-shaped film having excellent dimensional accuracy and film thickness accuracy, a sizing sleeve whose inside is reduced in pressure by a vacuum pump and a cooling water tank are used for sizing. A method for producing a thermoplastic polyimide tubular film that supplies a small amount of water to the inner ring of the sleeve is disclosed.

Japanese Patent No. 2731694 Japanese Patent No. 3237715

  However, for example, a thermoplastic elastomer material suitable for a paper feed roller and a transport roller such as a thermoplastic polyurethane resin is caused by friction with a sizing die as compared with the material used in the inventions described in Patent Documents 1 and 2 above. There is a tendency that deformation tends to occur. Therefore, when extruding such a thermoplastic elastomer material, even if the techniques described in Patent Documents 1 and 2 are applied, deformation due to friction cannot be sufficiently suppressed. As a result, the molded product cannot pass through the sizing die, so that the molding itself cannot be performed, or even if the molded product can be molded, the dimensions of the tubular molded product change.

  The present invention has been devised in view of the actual situation as described above, and an extrusion molding apparatus and a thermoplastic elastomer molded product that can obtain a high degree of dimensional accuracy even when a thermoplastic elastomer material that easily deforms due to friction is used. The main purpose is to provide a manufacturing method.

  The present invention is an extrusion molding apparatus for extruding a thermoplastic elastomer, the extrusion means for heating the thermoplastic elastomer to extrude it from a die, the take-up means for taking out the extruded thermoplastic elastomer, and the extrusion means. A shape adjusting means arranged between the take-out means and adjusting the shape of the extruded thermoplastic elastomer, the shape adjusting means having a water tank filled with cooling water for cooling the thermoplastic elastomer. And, the side wall defining the water tank is provided with an inlet made of a through hole for allowing the thermoplastic elastomer to enter the water tank, and an outlet made of a through hole for allowing the thermoplastic elastomer to exit the water tank, At least the diameter of the inlet is that of the thermoplastic elastomer immediately after entering the inlet after being extruded from the extrusion means. Greater than the diameter, the water level of the cooling water, being higher than the upper end of said inlet and said outlet.

  In the extrusion molding apparatus according to the present invention, it is preferable that the water tank has a first member attached to the side wall, and the inlet is formed in the first member.

  In the extrusion molding apparatus according to the present invention, the die extrudes the thermoplastic elastomer into a tube shape, and the water tank is a normal pressure water tank through which the thermoplastic elastomer extruded from the extrusion means first passes. And a reduced-pressure water tank provided on the downstream side of the normal-pressure water tank.

  In the extrusion molding apparatus according to the present invention, the water tank includes a first partition wall that partitions the normal pressure water tank and the vacuum water tank, and the first partition wall has a through hole through which the thermoplastic elastomer passes. A first passage port is formed, and the diameter of the first passage port is larger than the outer diameter of the thermoplastic elastomer immediately after entering the inlet after being pushed out from the extrusion means, Is preferably higher than the upper end of the first passage opening.

  In the extrusion molding apparatus according to the present invention, it is preferable that the water tank has a second member attached to the first partition wall, and the first passage port is formed in the second member. .

  In the extrusion molding apparatus according to the present invention, it is preferable that the length of the first passage port in the extrusion direction is 0.5 to 10 mm.

  In the extrusion molding apparatus according to the present invention, the reduced pressure water tank includes a first reduced pressure water tank, a second reduced pressure water tank provided on the downstream side of the first reduced pressure water tank, the first reduced pressure water tank, and the second reduced pressure water tank. A second partition wall for partitioning the water tank, wherein the second partition wall is provided with a second passage port including a through hole through which the thermoplastic elastomer passes, and the diameter of the second passage port is determined by the extrusion means. It is desirable that the coolant is larger than the outer diameter of the thermoplastic elastomer just before entering the inlet after being pushed out, and the coolant level is higher than the upper end of the second passage port.

  In the extrusion molding apparatus according to the present invention, the diameter of the inlet is 1.04 to 1.26 times the outer diameter of the thermoplastic elastomer immediately after entering the inlet after being extruded from the extrusion means. Is desirable.

  In the extrusion molding apparatus according to the present invention, it is desirable that the diameter of the first passage port and the diameter of the second passage port are 1.08 to 1.45 times the finished outer diameter of the thermoplastic elastomer. .

  In the extrusion molding apparatus according to the present invention, the decompression water tank is provided with position regulation means for regulating the top and bottom or left and right positions of the thermoplastic elastomer passing through the decompression water tank in the horizontal direction. desirable.

  In the extrusion molding apparatus according to the present invention, the position restricting means is a roller that contacts the thermoplastic elastomer while rotating and restricts the position of the thermoplastic elastomer, and a rotating shaft that rotatably supports the roller. It is desirable to have

  In the extrusion molding apparatus according to the present invention, it is preferable that a coating film for reducing friction with the thermoplastic elastomer is formed on the surface of at least one of the through holes.

  In the extrusion molding apparatus according to the present invention, it is desirable to further include a cutting means for cutting the thermoplastic elastomer taken up by the take-up means into a predetermined length.

  Furthermore, the present invention is characterized in that a molded product in which a tubular thermoplastic elastomer is cut into pieces is manufactured using the extrusion molding apparatus.

  In the extrusion molding apparatus of the present invention, the diameter of the inlet consisting of the through hole provided in the side wall of the water tank is larger than the outer diameter of the thermoplastic elastomer just before entering the inlet after being extruded from the extrusion means. Friction is suppressed between the extruded thermoplastic elastomer and the inlet. That is, instead of attaching a sizing die that is in close contact with the outer surface of the thermoplastic elastomer to the water tank, the thermoplastic elastomer is deformed by friction by providing a through-hole having a diameter larger than the outer diameter of the thermoplastic elastomer on the side wall of the water tank. This is suppressed, and it becomes possible to obtain excellent dimensional accuracy.

  Furthermore, since the water level of the cooling water is higher than the upper ends of the inlet and the outlet, the water film interposed between the inlet and the outlet and the thermoplastic elastomer passing therethrough prevents the air from entering the tank. Is prevented. Furthermore, the friction generated between the thermoplastic elastomer and the inlet and outlet is further suppressed by the lubricating action of the cooling water.

It is sectional drawing which shows one Embodiment of the extrusion molding apparatus of this invention. It is sectional drawing of the water tank of FIG. It is sectional drawing of the 1st normal pressure water tank of FIG. It is sectional drawing of the 1st decompression water tank of FIG. It is a perspective view which shows the structure of the position control tool of FIG.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view of an extrusion molding apparatus 1 according to this embodiment. The extrusion apparatus 1 is used for extrusion molding of a thermoplastic elastomer.

  As shown in FIG. 1, an extrusion molding apparatus 1 according to this embodiment includes an extruder (extruding means) 2, a take-up machine (take-up means) 3, a shape adjusting machine (shape adjusting means) 4, and a cutting machine ( Cutting means) 5.

  The extruder 2 is disposed in the uppermost stream of the extrusion molding apparatus 1 and heats and extrudes the thermoplastic elastomer 10. The take-up machine 3 takes up the thermoplastic elastomer 10 extruded by the extruder 2. The shape adjuster 4 is disposed between the extruder 2 and the take-up machine 3 and adjusts the shape of the thermoplastic elastomer 10 extruded by the extruder 2. The cutting machine 5 cuts the thermoplastic elastomer 10 taken by the take-up machine 3 into a predetermined length.

  The extruder 2 includes, for example, a hopper 21, a cylinder 22, a screw 23, a mandrel 24, and a die 25. The hopper 21 is charged with pellets 11 that are the material of the thermoplastic elastomer 10. The hopper 21 supplies the charged pellets 11 to the cylinder 22. The cylinder 22 heats and melts the pellets 11 supplied by the hopper 21 to produce a thermoplastic elastomer 10 having fluidity. The cylinder 22 is provided with a heater (not shown) for heating the pellet 11. The screw 23 is incorporated in the cylinder 22 and pushes the thermoplastic elastomer 10 heated and melted to the tip side of the cylinder 22.

  For example, the mandrel 24 is provided coaxially and integrally with the screw 23, and forms the thermoplastic elastomer 10 extruded by the screw 23 in a hollow shape. The die 25 is provided at the tip of the cylinder 22 and forms the outer shape of the thermoplastic elastomer 10 extruded by the screw 23. A tubular thermoplastic elastomer 10 is formed by the mandrel 24 and the die 25 and extruded from the outlet of the extruder 2.

  The take-up machine 3 includes, for example, a pair of rollers 31 that contacts the thermoplastic elastomer 10 extruded from the extruder 2 and pulls out the thermoplastic elastomer 10, and a roller drive unit (not shown) that rotationally drives the roller 31. Have. The number of rotations of the roller 31 is controlled to be interlocked with the number of rotations of the screw 23, for example.

  The shape adjusting machine 4 has a water tank 40 filled with cooling water W for cooling the thermoplastic elastomer 10. The water tank 40 is partitioned by a bottom wall 41, an upstream side wall 42, a downstream side wall 43, and a top wall 44. The upstream side wall 42 is provided with an inlet 45 a made up of a through hole through which the thermoplastic elastomer 10 extruded from the extruder 2 enters the water tank 40. The downstream side wall 43 is provided with an outlet 45 b made of a through hole through which the thermoplastic elastomer 10 exits from the water tank 40. The water tank 40 is, for example, sequentially from the upstream side in the extrusion direction of the thermoplastic elastomer 10 to the downstream side, the first normal pressure water tank 61, the first reduced pressure water tank 62, the second reduced pressure water tank 63, and the second normal pressure water tank 64. It is partitioned.

  The high-temperature thermoplastic elastomer 10 extruded from the extruder 2 is stretched by the tension applied by the take-up machine 3, and its outer diameter gradually decreases. Further, the thermoplastic elastomer 10 passing through the water tank 40 in the meantime is cooled and contracted by heat exchange with the cooling water W. Eventually, when the temperature of the thermoplastic elastomer 10 is sufficiently lowered, the shape of the thermoplastic elastomer 10 is stabilized.

  The cutting machine 5 includes, for example, a cutter 51 that cuts the thermoplastic elastomer 10 taken by the take-up machine 3 and a cutter driving unit (not shown) that reciprocates the cutter 51 in the vertical direction. The reciprocation cycle of the cutter 51 is controlled to be interlocked with, for example, the number of rotations of the roller 31 of the take-up machine 3. Thereby, the tube-shaped thermoplastic elastomer 10 is cut | disconnected by predetermined length. The cut tube is used as a molded product such as a paper feed roller 12 used in a paper feeding mechanism such as an image forming apparatus.

  FIG. 2 shows the configuration of the water tank 40. The water tank 40 includes a first normal pressure water tank 61, a first reduced pressure water tank 62, a second reduced pressure water tank 63, and a second normal pressure water tank 64. The 1st normal pressure water tank 61 is arrange | positioned at the uppermost stream side of the water tank 40 so that the thermoplastic elastomer 10 extruded from the extruder 2 may pass first. The thermoplastic elastomer 10 that has passed through the first normal pressure water tank 61 sequentially passes through the first reduced pressure water tank 62, the second reduced pressure water tank 63, and the second normal pressure water tank 64.

  The first normal pressure water tank 61 and the first reduced pressure water tank 62 are partitioned by the first partition wall 46. The first partition wall 46 is provided with a first passage port 72a composed of a through hole through which the thermoplastic elastomer 10 passes. The first decompression water tank 62 and the second decompression water tank 63 are partitioned by a second partition wall 47. The second partition wall 47 is provided with a second passage port 73a formed of a through hole through which the thermoplastic elastomer 10 passes. The second decompression water tank 63 and the second atmospheric water tank 64 are partitioned by a third partition wall 48. The third partition wall 48 is provided with a third passage port 74a composed of a through hole through which the thermoplastic elastomer 10 passes.

  The upper parts of the first atmospheric water tank 61 and the second atmospheric water tank 64 are open to the atmosphere. Thereby, the pressure of the 1st normal pressure water tank 61 and the 2nd normal pressure water tank 64 is maintained at a normal pressure. On the other hand, the upper portions of the first decompression water tank 62 and the second decompression water tank 63 are closed by the top wall 44, and the air inside the first decompression water tank 62 and the second decompression water tank 63 is drawn out by the vacuum pump P. Yes. Thereby, the pressure of the 1st decompression water tank 62 and the 2nd decompression water tank 63 is lower than atmospheric pressure, and a substantially vacuum state is maintained.

  When the thermoplastic elastomer 10 passes through the first reduced pressure water tank 62 and the second reduced pressure water tank 63, a pressure difference is generated between the inside of the normal pressure tube and the outside of the reduced pressure tube. Due to this pressure difference, the thermoplastic elastomer 10 projects uniformly outward in the radial direction, and the shape of the thermoplastic elastomer 10 is maintained.

  The technique for depressurizing the first reduced pressure water tank 62 and the second reduced pressure water tank 63 is not particularly limited. For example, a general decompression technique such as a technique using a Venturi tube can be applied.

  The length of each water tank in the extrusion direction can be set as appropriate. For example, the length of the first normal pressure water tank 61 in the extrusion direction may be set smaller than the length of the first decompression water tank 62 in the extrusion direction. Furthermore, the volume in the extrusion direction of each water tank can be set as appropriate. For example, the volume of the first normal pressure water tank 61 may be set smaller than the volume of the first reduced pressure water tank 62. The volume of the 1st decompression water tank 62 and the volume of the 2nd decompression water tank 63 are equivalent. The volume of the second atmospheric water tank 64 is set larger than the volume of the second vacuum water tank 63.

  A water supply tank T is connected to the first normal pressure water tank 61 and the second normal pressure water tank 64, and a water supply amount is provided by a flow rate adjusting valve (not shown) or the like so that a desired water level is obtained in each water tank. Has been adjusted. The same applies to the first decompressed water tank 62 and the second decompressed water tank 63.

  FIG. 3 shows the configuration of the first normal pressure water tank 61 and its surroundings. The first atmospheric pressure water tank 61 is partitioned by a side wall 42, a first partition wall 46, a cylindrical member 66, and the like. A ring-shaped gasket 67 is provided at the joint between the side wall 42 and the tubular member 66 and at the joint between the first partition wall 46 and the tubular member 66. An opening 66a is formed in the upper part of the cylindrical member 66, and the upper part of the cylindrical member 66 is open to the atmosphere. A water receiving portion 49 is provided below the side wall 42 and the cylindrical member 66.

  The side wall 42 has a pair of water supply ports 42a at the upper part and the lower part thereof. A water supply pipe joint 42b is attached to each water supply port 42a. Each water supply pipe joint 42 b is connected to a water supply tank T, and the water supply port 42 a allows the cooling water supplied from the water supply tank T to flow into the first atmospheric pressure water tank 61. The cooling water W that has flowed into the first normal pressure water tank 61 cools the thermoplastic elastomer 10 passing through the first normal pressure water tank 61, and then overflows from the inlet 45a and the opening 66a to become water droplet-like cooling water W1. It falls and is stored in the water receiver 49.

  The water level of the cooling water W in the first atmospheric pressure water tank 61 is maintained higher than the upper end of the inlet 45a by adjusting the flow rate adjustment valve provided in the piping path between the water supply tank T and the water supply pipe joint 42b. Has been. For this reason, the entire surface of the thermoplastic elastomer 10 passing through the inlet 45a is covered with a water film of the cooling water W.

  A drain outlet 49a is formed in the lower part of the water receiver 49, and a drain pipe joint 49b is provided in the drain outlet 49a. The cooling water W2 stored in the water receiver 49 is discharged to the outside of the water receiver 49 through the drain port 49a and the drain pipe joint 49b. The cooling water W2 discharged through the drain pipe joint 49b may be configured to circulate to the water supply tank T. The water level of the second atmospheric water tank 64 shown in FIG. 2 is also maintained by the same configuration as above.

  An opening 42c for inserting the thermoplastic elastomer 10 is formed in the side wall 42, and a plate-like first member 71 is attached to the opening 42c. In the first member 71, an inlet 45 a of the water tank 40 is formed so as to penetrate the first member 71. The diameter of the inlet 45a is set to be smaller than the diameter of the opening 42c and larger than the outer diameter of the thermoplastic elastomer 10 immediately after entering the inlet 45a after being extruded from the extruder 2.

  When the diameter D1 of the inlet 45a is equal to or smaller than the outer diameter D0 of the thermoplastic elastomer 10 immediately before entering the inlet 45a, the friction generated between the thermoplastic elastomer 10 and the inlet 45a is the same as in the prior art using a sizing die. Increases and affects the accuracy of the finished dimensions of the thermoplastic elastomer 10. On the other hand, when the diameter D1 of the inlet 45a is excessively large, a large amount of the cooling water W1 flows out from the inlet 45a, and it becomes difficult to maintain the water level of the first atmospheric pressure water tank 61. From such a point of view, the diameter D1 of the inlet 45a is 1.04 to 1.26 times the outer diameter D0 of the thermoplastic elastomer 10 after being extruded from the extruder 2 and immediately before entering the inlet 45a. desirable.

  The diameter of the outlet 45b is the same as described above, but the temperature of the thermoplastic elastomer 10 entering the outlet 45b is decreased by heat exchange with the cooling water W in the water tank 40, so the diameter of the outlet 45b is , May be set smaller than the diameter D1 of the inlet 45a.

  The inlet 45a is a through hole through which the thermoplastic elastomer 10 first passes among the through holes provided in the water tank 40, and the thermoplastic elastomer 10 whose shape is unstable at a high temperature immediately after extrusion passes therethrough. Therefore, in order to suppress the deformation of the thermoplastic elastomer 10 and improve the dimensional accuracy, it is effective to suppress the friction generated between the thermoplastic elastomer 10 and the inlet 45a.

  In the present embodiment, the length in the extrusion direction of the first member 71 where the inlet 45a is formed is equal to the length in the extrusion direction of the second member 72 where a first passage port 72a described later is formed. It may be set smaller. Thus, the length of the inlet 45a in the extrusion direction (corresponding to the thickness of the plate-like first member 71) is the same as the length of the first passage port 72a in the extrusion direction (the length of the cylindrical second member 72). The friction in the through-hole through which the thermoplastic elastomer 10 first passes is reduced, and the accuracy of the extrusion dimension of the thermoplastic elastomer 10 can be further increased.

  The first decompression water tank 62 is partitioned by a plate-like member 46a attached to the first partition wall 46, a plate-like member 47a attached to the second partition wall 47, the bottom wall 41, the top wall 44, and the like. Yes. The plate-like member 46a and the plate-like member 47a are joined to the first partition wall 46 and the second partition wall 47 via screws or the like, and the joint surface between the plate-like member 46a and the first partition wall 46 and the plate-like member 47a. A sheet-like gasket 75 is provided on the joint surface between the first partition wall 47 and the second partition wall 47.

  An opening 46b for inserting the thermoplastic elastomer 10 is formed in the first partition wall 46, and a cylindrical second member 72 is attached to the opening 46b. The second member 72 is formed with a first passage port 72a for guiding the thermoplastic elastomer 10 from the first normal pressure water tank 61 to the first reduced pressure water tank 62 so as to penetrate the second member 72 in the axial direction. . It is desirable that the diameter D2 of the first passage port 72a is smaller than the diameter of the opening 46b and larger than the outer diameter D0 of the thermoplastic elastomer 10 that is extruded from the extruder 2 and immediately before entering the inlet. Since the outer diameter of the thermoplastic elastomer 10 immediately before entering the first passage opening 72a is smaller than the outer diameter D0, even if the diameter D2 is smaller than the outer diameter D0, the first passage opening 72a. If it is larger than the outer diameter immediately before entering, the friction at the first passage port 72a is reduced.

  When the diameter D2 of the first passage port 72a is equal to or smaller than the outer diameter of the thermoplastic elastomer 10 entering the first passage port 72a, the friction generated between the thermoplastic elastomer 10 and the first passage port 72a increases, The accuracy of the extrusion dimension of the plastic elastomer 10 is affected. On the other hand, when the diameter D2 of the first passage port 72a is excessively large, a large amount of the cooling water W1 flows out from the first passage port 72a, and it becomes difficult to maintain the water level of the first atmospheric pressure water tank 61. From such a viewpoint, the diameter D2 of the first passage port 72a is desirably 1.08 to 1.45 times the finished outer diameter of the thermoplastic elastomer 10. Here, the finished dimension or finished outer diameter is the dimension or outer diameter of the thermoplastic elastomer 10 finished as a molded product.

  Since the water pressure in the first depressurized water tank 62 is lower than the water pressure in the first normal pressure water tank 61, a part of the cooling water W filled in the first normal pressure water tank 61 is the second of the first partition wall 46. It flows into the first reduced pressure water tank 62 from the first passage port 72 a provided in the member 72. At this time, the water level of the first atmospheric pressure water tank 61 is maintained higher than the upper end of the first passage port 72a so that air does not pass through the first passage port 72a. On the other hand, since the first depressurized water tank 62 is depressurized by the vacuum pump P, the water level of the first depressurized water tank 62 is higher than the water level of the first normal pressure water tank 61.

  The second reduced pressure water tank 63 has the same configuration as the first reduced pressure water tank 62. That is, the second decompression water tank 63 includes a plate-like member 47b attached to the second partition wall 47, a plate-like member (not shown) attached to the third partition wall 48 (see FIG. 2), and a bottom wall. 41 and the top wall 44 and the like. The plate-like member 47 b is joined to the second partition wall 47 via a screw or the like, and a sheet-like gasket 75 is provided on the joint surface between the plate-like member 47 b and the second partition wall 47.

  The second partition wall 47 is formed with an opening 47c through which the thermoplastic elastomer 10 is inserted, and a cylindrical third member 73 is attached to the opening 47c. The third member 73 is formed with a second passage port 73a for guiding the thermoplastic elastomer 10 from the first reduced pressure water tank 62 to the second reduced pressure water tank 63 so as to penetrate the second member 73 in the axial direction. The diameter D3 of the second passage port 73a is preferably smaller than the diameter of the opening 47c and larger than the outer diameter of the thermoplastic elastomer 10 immediately after entering the inlet after being extruded from the extruder 2. Since the outer diameter of the thermoplastic elastomer 10 immediately before entering the second passage port 73a is smaller than the outer diameter D0, even if the diameter D3 is smaller than the outer diameter D0, the second passage port 73a. If it is larger than the outer diameter just before entering, the friction at the second passage port 73a is reduced. Further, the diameter D3 of the second passage port 73a is desirably 1.08 to 1.45 times the finished outer diameter of the thermoplastic elastomer 10, similarly to the diameter D2 of the first passage port 72a. The same applies to the diameter D4 of the third passage port 74a.

  Since the water pressure in the second depressurized water tank 63 is lower than the water pressure in the second normal pressure water tank 64, a part of the cooling water W filled in the second normal pressure water tank 64 is provided in the third partition wall 48. It flows into the 2nd pressure-reduced water tank 63 from the 4th passage port 74a (refer FIG. 2). At this time, the water level of the second atmospheric pressure water tank 64 is maintained higher than the upper end of the fourth passage port 74a so that air does not pass through the fourth passage port 74a. On the other hand, since the second depressurized water tank 63 is depressurized by the vacuum pump P, the water level of the second depressurized water tank 63 is higher than the water level of the second normal pressure water tank 64.

  The inlet 45a, the first passage port 72a, the second passage port 73a, the third passage port 74a, and the outlet 45b formed of the through holes are formed of a thermoplastic elastomer so as to reduce friction generated when the thermoplastic elastomer 10 passes. 10 are arranged in a straight line in the extrusion direction.

  The thermoplastic elastomer 10 passing through the water tank 40 may be slightly vibrated under the influence of the flow of the cooling water W supplied into the water tank 40. Therefore, even if the inlet 45a, the first passage port 72a, the second passage port 73a, the third passage port 74a, and the outlet 45b are arranged in a straight line in the extrusion direction of the thermoplastic elastomer 10, the thermoplastic elastomer 10 penetrates therethrough. There is a risk of contact with the surface of the hole. Therefore, it is desirable that a coating film that reduces friction with the thermoplastic elastomer 10 is formed on the surface of at least one of the through holes.

  FIG. 4 shows the configuration of the first reduced-pressure water tank 62 in a cross section perpendicular to the extrusion direction of the thermoplastic elastomer 10. Since the structure of the 2nd decompression water tank 63 is also equivalent to the structure of the 1st decompression water tank 62, hereafter, the 1st decompression water tank 62 is demonstrated. The first decompression water tank 62 is a position restriction that restricts the position of the rectangular tubular member 81, the carriage 82 that supports the tubular member 81, and the thermoplastic elastomer 10 that passes through the first decompression water tank 62 in a substantially horizontal direction. Tools (position regulating means) 83 and the like.

  The cylindrical member 81 constitutes the bottom wall 41, the top wall 44, and the left and right side walls 84a and 84b of the first decompression water tank 62. The top wall 44 is provided with an opening 44 a for inserting the position restricting tool 83 into the first decompressed water tank 62, and the side wall 84 a is fixed to the bottom of the first decompressed water tank 62. An opening 84c is provided. A hatch 85a and a hatch 85b are attached to the opening 44a and the opening 84c, respectively. In order to ensure the air tightness and water tightness of the first decompression water tank 62, a gasket 85c and a gasket 85d are provided around the opening 44a and around the opening 84c, respectively.

  A water supply port 41a is formed in the bottom wall 41 of the first decompression water tank 62, and a water supply pipe joint 87a is provided in the water supply port 41a. The water supply pipe joint 87 a is connected to the water supply tank T, and the water supply port 41 a allows the cooling water W supplied from the water supply tank T to flow into the first decompression water tank 62.

  A drain outlet 84d is formed in the lower part of the side wall 84b of the first decompression water tank 62, and a drain pipe joint 87b is provided in the drain outlet 84d. The cooling water W that has flowed into the first reduced pressure water tank 62 cools the thermoplastic elastomer 10 passing through the first reduced pressure water tank 62, and then is discharged to the outside of the first reduced pressure water tank 62 through the drain port 84d and the drain pipe joint 87b. Is done. The water level of the cooling water W in the first depressurized water tank 62 is adjusted by adjusting the flow rate adjusting valve provided in the piping path between the water supply tank T and the water supply pipe joint 87a (see FIG. 3). ) Is kept higher than the upper end of. The cooling water W discharged via the drain pipe joint 87b may be configured to circulate to the water supply tank T.

  An exhaust port 84e is formed in the upper part of the side wall 84b of the first decompression water tank 62, and an exhaust pipe joint 87c is provided in the exhaust port 84e. The exhaust pipe joint 87 c is connected to the vacuum pump P, and the air in the upper space of the first reduced pressure water tank 62 is drawn out by the vacuum pump P, and the reduced pressure state of the first reduced pressure water tank 62 is maintained.

  The first decompression water tank 62 filled with the cooling water W is supported by a carriage 82, for example. The carriage 82 is joined to the bottom wall 41 of the first decompression water tank 62, that is, the lower part of the cylindrical member 81 by welding or the like. A rail 82a, wheels 82b, and the like are provided at the lower portion of the carriage 82. The carriage 82 is configured to be movable in the front-rear direction parallel to the extrusion direction of the thermoplastic elastomer 10 and in the left-right direction perpendicular thereto by the rails 82a and the wheels 82b. By moving the carriage 82 in the above direction, the position of the water tank 40 with respect to the extruder 2 is adjusted.

  The position restricting tool 83 includes a roller 91, a rotation shaft 92, and a support portion 93, and restricts the vertical position and the left / right position of the thermoplastic elastomer 10 that passes through the first reduced pressure water tank 62 in the horizontal direction.

  The roller 91 contacts the upper surface of the thermoplastic elastomer 10 while rotating, and regulates the vertical position of the thermoplastic elastomer 10. The roller 91 has a guide portion 91a that contacts the upper surface of the thermoplastic elastomer 10 and guides the thermoplastic elastomer 10, and a pair of flange portions 91b formed at both ends of the guide portion 91a, and is formed in a bobbin shape. Yes. The outer diameter of the roller 91 gradually increases from the equator of the roller 91 toward both ends in the axial direction so that the vertical and horizontal positions of the thermoplastic elastomer 10 can be regulated while the roller 91 rotates. Thereby, the cross section of the roller 91 is formed in the gentle arc shape from the guide part 91a to the flange part 91b. As shown in FIG. 4, in the cross section including the rotating shaft 92, the radius of curvature from the guide portion 91 a to the flange portion 91 b is set to be slightly larger than the outer radius of the thermoplastic elastomer 10 that passes through the position restricting tool 83. . The roller 91 incorporates a pair of bearings 91 c so that the roller 91 can smoothly rotate around the rotation shaft 92.

  FIG. 5 shows the configuration of the position restricting tool 83 and the positional relationship between the position restricting tool 83, the first partition wall 46, and the second partition wall 47 in the first decompression water tank 62. The rotating shaft 92 rotatably supports the roller 91. The rotating shaft 92 is fixed to the support portion 93 by a screw 92a or the like. The support portion 93 is formed with a through hole 93 a for allowing the rotation shaft 92 to be inserted therethrough.

  The through-hole 93 a is configured by a long hole that is long in the vertical direction, that is, in the height direction of the roller 91. With the through hole 93a having such a shape, the height of the rotating shaft 92, that is, the height of the roller 91 can be adjusted as shown by a two-dot chain line in FIG.

  In FIG. 5, a plate-like second member 75 is attached to the first partition wall 46 instead of the cylindrical second member 72 (see FIG. 3). Similarly, a plate-like third member 76 is attached to the second partition wall 47. The point that the first passage port 72a is formed in the second member 75 and the second passage port 73a is formed in the third member 76 is the same as described above.

  Since a pressure difference is generated between the first normal pressure water tank 61 and the first reduced pressure water tank 62, when the length of the second members 72, 75 in the extrusion direction is less than 0.5 mm, the second members 72, 75 There is a possibility that the strength of the is insufficient. On the other hand, as described above, the thermoplastic elastomer 10 passing through the water tank 40 is affected by the flow of the cooling water W supplied into the water tank 40 and vibrates slightly. When the length in the extrusion direction exceeds 10 mm, the friction generated between the thermoplastic elastomer 10 and the first passage port 72a is increased, which may affect the accuracy of the extrusion dimension of the thermoplastic elastomer 10. From such a viewpoint, the plate-like second member 75 shown in FIG. 5 is preferable to the cylindrical second member 72 shown in FIG. 3, and the length of the second member 75 in the extrusion direction is 0.5. 10 mm is desirable.

  When the thermoplastic elastomer 10 having a specific gravity smaller than that of the cooling water W filled in the first decompression water tank 62 is used, due to the influence of buoyancy, the upper surface of the thermoplastic elastomer 10, the first passage port 72a and the second passage port. There exists a tendency for the upper surface of 73a to contact easily.

  However, in the present embodiment, the inner lower surface of the guide portion 91a of the roller 91 guides the upper surface of the thermoplastic elastomer 10 and restricts the vertical position and further the horizontal position. At this time, as shown in FIG. 5, since the upper end of the first passage port 72a, the inner lower surface of the guide portion 91a of the roller 91 and the upper end of the second passage port 73a are arranged in a straight line, the thermoplastic elastomer 10 Passes straight without meandering through the first reduced-pressure water tank 62, and the contact between the thermoplastic elastomer 10, the first passage port 72a and the second passage port 73a is effectively avoided. Thereby, the friction which arises between the thermoplastic elastomer 10, and the 1st passage port 72a and the 2nd passage port 73a can be reduced.

  On the other hand, when the thermoplastic elastomer 10 having a specific gravity smaller than that of the cooling water W is used, the height of the roller 91 may be adjusted so that the inner upper surface of the guide portion 91 a guides the lower surface of the thermoplastic elastomer 10.

  The roller 91 that guides the thermoplastic elastomer 10 is rotatably supported by the rotating shaft 92 via the bearing 91c, and thus rotates with the passage of the thermoplastic elastomer 10 and does not hinder the movement of the thermoplastic elastomer 10. . Therefore, since friction hardly occurs between the guide portion 91 a of the roller 91 and the thermoplastic elastomer 10, deformation of the thermoplastic elastomer 10 when passing the position restricting tool 83 is avoided.

  According to the extrusion molding apparatus 1 of the present embodiment having the above-described configuration, after the diameter D1 of the inlet 45a formed of a through hole provided in the side wall 42 of the water tank 40 is extruded from the extruder 2, the inlet Since it is larger than the outer diameter D0 of the thermoplastic elastomer 10 immediately before entering the space, it is possible to suppress friction between the thermoplastic elastomer 10 and the inlet 45a. That is, instead of attaching a sizing die that is in close contact with the outer surface of the thermoplastic elastomer 10 to the water tank 40, the side wall 42 of the water tank 40 is provided with a through hole having a diameter D 1 larger than the outer diameter D 0 of the thermoplastic elastomer 10. The plastic elastomer 10 is suppressed from being deformed by friction, and excellent dimensional accuracy can be obtained.

  Further, since the water level of the cooling water W is higher than the upper ends of the inlet 45a and the outlet 45b, the water tank is formed by the water film of the cooling water W interposed between the inlet 45a and the outlet 45b and the thermoplastic elastomer 10 passing therethrough. The entry of air into 40 is prevented. Furthermore, the friction generated between the thermoplastic elastomer 10 and the inlet 45a and outlet 45b is further suppressed by the lubricating action of the cooling water W.

  Since the inlet 45a is formed in the first member 71, the first member 71 having different specifications such as the diameter D1 and length of the inlet 45a can be easily used properly. By appropriately replacing the first member 71 as described above, the inlet 45a having the optimum specification can be used according to the size, size and material of the thermoplastic elastomer 10, and the dimensional accuracy of the thermoplastic elastomer 10 can be increased. Is possible.

  Since the water tank 40 has the 1st normal pressure water tank 61 through which the thermoplastic elastomer 10 extruded from the extruder 2 first passes, it is prevented that air flows into the 1st pressure-reduced water tank 62, and the 1st pressure-reduced water tank 62 is provided. The reduced pressure state can be maintained. As a result, the dimensional accuracy of the thermoplastic elastomer 10 can be further increased.

  Since the first normal pressure water tank 61 through which the thermoplastic elastomer 10 extruded from the extruder 2 first passes has a high water pressure, it is difficult to appropriately adjust the shape if it is normal. However, in the present embodiment, since the volume of the first normal pressure water tank 61 is smaller than that of the first reduced pressure water tank 62, the shape adjusting action in the first normal pressure water tank 61 is small, and the first reduced pressure water tank having a low water pressure. From 62 onward, a large shape adjusting effect can be obtained. As a result, the dimensional accuracy of the thermoplastic elastomer 10 can be further increased.

  Since the 1st passage port 72a is formed in the 2nd member 72, the 2nd member 72 from which specifications, such as diameter D2 and length of the 1st passage port 72a differ, can be used properly. By appropriately replacing the second member 72 as described above, the first passage port 72a having the optimum specification can be used according to the size, size and material of the thermoplastic elastomer 10, and the dimensional accuracy of the thermoplastic elastomer 10 can be improved. It is further enhanced. The same applies to the second passage port 73a and the third passage port 74a.

  As mentioned above, although the extrusion molding apparatus of this invention was demonstrated in detail, this invention is changed and implemented in various aspects, without being limited to said specific embodiment.

  A thermoplastic elastomer was prototyped based on the specifications shown in Table 1 using an extrusion molding apparatus having the basic configuration shown in FIG. 1, and its dimensional accuracy was tested. In Examples 1 to 6 and Comparative Examples 1 to 3 in Table 1, thermoplastic polyurethane resin pellets (Elastolan C60A10WN manufactured by BASF Japan) were dried at 80 ° C. for 3 hours, and then the screw diameter was φ50 mm. And was molded at a melting temperature of 160 ° C. In Example 7, the material was changed to a thermoplastic polyurethane-based resin (Hytrel 4047 manufactured by Toray DuPont Co., Ltd.), and molding was performed at a melting temperature of 180 ° C., but other specifications were as in Example 6. It is equivalent.

  In Comparative Example 1, 20 mm was tested as the diameter of the inlet and the first to third passage ports. In Comparative Example 2, 33 mm was tested as the diameter of the inlet and the first to third passage ports. In Comparative Example 3, 40 mm was tested as the diameter of the inlet and the first to third passage ports. The test method is as follows.

<Diameter just before entrance>
A laser dimension measuring machine (LS-3032) manufactured by Keyence Corporation was used, and the outer diameter of the thermoplastic elastomer just before entering the inlet was measured.

<Finishing outer diameter>
The outer diameter of the finished product of the thermoplastic elastomer was measured with the above laser dimension measuring machine.

<Dimensional accuracy>
A cylindrical taper gauge (TPG-710C) manufactured by Niigata Seiki Co., Ltd. was used, and the inner diameter of the finished product of the extruded thermoplastic elastomer was measured. During the continuous molding for 2 hours, 30 thermoplastic elastomers were sampled at intervals of 4 minutes. The evaluation was evaluated as ◎ if the standard deviation of the sampled inner diameter was less than 0.3, ○ if it was 0.3 or more and less than 0.5, or x if 0.5 or more or molding could not be performed.

  As is clear from Table 1, it was confirmed that the extrusion molding apparatus of the example significantly improved the dimensional accuracy of the finished product as compared with the comparative example.

DESCRIPTION OF SYMBOLS 1 Extrusion molding apparatus 2 Extruder (extrusion means)
3 Take-up machine (take-up means)
4 Shape adjuster (shape adjuster)
5 Cutting machine (cutting means)
DESCRIPTION OF SYMBOLS 10 Thermoplastic elastomer 25 Dies 40 Water tank 42 Side wall 45a Inlet 45b Outlet 46 1st partition wall 47 2nd partition wall 61 1st normal pressure water tank 62 1st decompression water tank 63 2nd decompression water tank 71 1st member 72a 1st passage port 72 Second member 73a Second passage port 83 Position restricting tool (position restricting means)
91 Roller 92 Rotating shaft

Claims (14)

An extrusion apparatus for extruding a thermoplastic elastomer,
An extrusion means for heating and extruding the thermoplastic elastomer from a die;
Take-up means for taking up the extruded thermoplastic elastomer;
A shape adjusting means arranged between the extruding means and the take-out means and adjusting the shape of the extruded thermoplastic elastomer;
The shape adjusting means has a water tank filled with cooling water for cooling the thermoplastic elastomer,
The side wall defining the water tank is provided with an inlet made of a through hole for allowing the thermoplastic elastomer to enter the water tank and an outlet made of a through hole for allowing the thermoplastic elastomer to exit the water tank,
At least the diameter of the inlet is larger than the outer diameter of the thermoplastic elastomer immediately after entering the inlet after being extruded from the extrusion means,
The extrusion apparatus according to claim 1, wherein a level of the cooling water is higher than upper ends of the inlet and the outlet.   The extrusion apparatus according to claim 1, wherein the water tank has a first member attached to the side wall, and the inlet is formed in the first member. The die extrudes the thermoplastic elastomer into a tube shape,
The extrusion molding according to claim 1 or 2, wherein the water tank has a normal pressure water tank through which the thermoplastic elastomer extruded from the extrusion means first passes, and a reduced pressure water tank provided on the downstream side of the normal pressure water tank. apparatus. The water tank includes a first partition wall that partitions the normal pressure water tank and the reduced pressure water tank,
The first partition wall is provided with a first passage port including a through hole through which the thermoplastic elastomer passes,
The diameter of the first passage port is larger than the outer diameter of the thermoplastic elastomer immediately after entering the inlet after being extruded from the extrusion means,
The extrusion molding apparatus according to claim 3, wherein a level of the cooling water is higher than an upper end of the first passage port.   The extrusion apparatus according to claim 4, wherein the water tank has a second member attached to the first partition wall, and the first passage port is formed in the second member.   The extrusion molding apparatus according to claim 5, wherein the length of the first passage port in the extrusion direction is 0.5 to 10 mm. The depressurized water tank includes a first depressurized water tank, a second depressurized water tank provided on the downstream side of the first depressurized water tank, a second partition wall that partitions the first depressurized water tank and the second depressurized water tank,
The second partition wall is provided with a second passage port including a through hole through which the thermoplastic elastomer passes,
The diameter of the second passage port is larger than the outer diameter of the thermoplastic elastomer immediately after entering the inlet after being extruded from the extrusion means,
The extrusion molding apparatus according to any one of claims 4 to 6, wherein a level of the cooling water is higher than an upper end of the second passage port.   The diameter of the inlet is 1.04-1.26 times the outer diameter of the thermoplastic elastomer immediately after entering the inlet after being extruded from the extrusion means. Extrusion equipment.   9. The extrusion molding apparatus according to claim 1, wherein a diameter of the first passage port and a diameter of the second passage port are 1.08 to 1.45 times a finished outer diameter of the thermoplastic elastomer. .   The position of the said pressure-reduced water tank is provided with the position control means to control the upper and lower and / or right-and-left position of the said thermoplastic elastomer which passes the inside of this pressure-reduced water tank in a horizontal direction. Extrusion equipment.   The extrusion molding apparatus according to claim 10, wherein the position restricting means includes a roller that contacts the thermoplastic elastomer while rotating and restricts a position of the thermoplastic elastomer, and a rotating shaft that rotatably supports the roller. .   The extrusion molding apparatus according to any one of claims 1 to 11, wherein a coating film for reducing friction with the thermoplastic elastomer is formed on a surface of at least one of the through holes.   The extrusion molding apparatus according to any one of claims 1 to 12, further comprising a cutting means for cutting the thermoplastic elastomer taken up by the take-up means into a predetermined length.   A method for producing a thermoplastic elastomer molded product, comprising producing a molded product obtained by rounding a tubular thermoplastic elastomer using the extrusion molding apparatus according to claim 13.

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