JP2011046047A - Extrusion molding die, extrusion molding device and medical tube - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an extrusion molding die which includes molding materials with properties differing at one edge part and the other edge part, and enables a rapid/smooth changing of the volume ratio of the different molding materials, when molding a medical tube having a migration part consisting of an outer layer and an inner layer, as well as an extrusion molding device and the medical tube. <P>SOLUTION: The extrusion molding die 20 includes an angular body 21 with a formed outer circumferential side recessed part 21a, an outer mandrel 22 which is installed inside the outer circumferential side recessed part 21a and has an outer circumferential side flow passage A formed between the mandrel 22 and the outer circumferential side recessed part 21a, with a formed inner circumferential side recessed part 22a, an inner mandrel 23 which is installed inside the inner circumferential side recessed part 22a and has an inner circumferential side flow passage B formed between the inner mandrel 23 and the inner circumferential side recessed part 22a, and a tube shape forming part for molding the medical tube 10 by making a confluence of the outer circumferential side flow passage A and the inner circumferential side flow passage B. Further, the outer circumferential side flow passage A and the inner circumferential side flow passage B are gradually ramified successively from the upstream side to the downstream side. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an extrusion mold, an extrusion apparatus, and an apparatus for molding a medical tube used for draining drainage fluid from a patient's wound or supplying chemical liquid to the patient's wound. The present invention relates to a molded medical tube.

  Conventionally, medical tubes have been used to drain the drainage fluid that accumulates in the patient's wounds and supply chemicals to the patient's wounds. By configuring the side and the tip side with molding materials having different characteristics, for example, there is one in which the hardness is changed and a portion where the hardness gradually changes is formed at the boundary transition portion. A medical tube including portions having different hardnesses is molded using an extrusion molding apparatus including an extrusion mold in which two injection holes for injecting different molding materials are formed (for example, Patent Documents). 1).

  This forming apparatus constitutes a part of a manufacturing apparatus including a core wire sending machine, a take-up machine, a winder, and the like. A kneading screw device and a first plasticizing screw device connected to both sides of the kneading screw device And a second plasticizing screw device. The kneading screw device includes a die and a screw disposed inside the die. A core wire extends from the core wire feeder, and this core wire passes through the inside of the screw of the kneading screw device and then extends to the winder via the take-up machine. And when forming a tube, while pulling a core wire with a take-up machine, first, a hard resin is supplied from a first plasticizing screw device to a kneading screw device to form a tube on the surface of the core wire.

  Next, the soft resin is supplied from the second plasticizing screw device to the kneading screw device while gradually increasing the supply amount while gradually decreasing the supply amount of the hard resin. Then, after stopping the supply of the hard resin, only the soft resin is supplied. As a result, a tube is formed in which the front end side is hard and the rear end side is soft, and the transition portion at the boundary between the hard portion and the soft portion gradually changes from hard to soft. Then, the molded tube is wound up by a winder.

JP 2001-293770 A

  In a medical tube composed of a hard part and a soft part, it is preferable to shorten the length of the transition part between the hard part and the soft part and to smooth the change in the hardness of the transition part. Moreover, it may be preferable to make the transition part into a double layer of the soft outer layer and the hard inner layer while sufficiently retaining the characteristics of the hard resin and the soft resin. However, since the volume between the inner peripheral surface of the die and the outer peripheral surface of the screw in which the molding material is kneaded is large in the molding apparatus described above, when molding a thin medical tube, the volume ratio of different molding materials is set. It is difficult to change smoothly and rapidly.

  For this reason, the conventional molding apparatus has a problem that it is difficult to shorten the length of the transition portion between the hard portion and the soft portion and smooth the change in hardness of the transition portion. Moreover, in the conventional molding apparatus, when the hard resin and the soft resin are simultaneously supplied into the kneading screw apparatus, the hard resin and the soft resin are kneaded in the kneading screw apparatus, so that the outer layer and the inner layer made of different molding materials are used. And cannot be formed. Furthermore, since the conventional forming apparatus uses a core wire, there is a problem that the manufacturing apparatus becomes complicated.

  The present invention has been made in view of such circumstances, and an object thereof is medical treatment in which one end side portion and the other end side portion are made of molding materials having different characteristics, and a boundary transition portion is made of an outer layer and an inner layer. An object of the present invention is to provide an extrusion mold, an extrusion molding apparatus, and a medical tube molded thereby, which can smoothly and rapidly change the volume ratio of different molding materials when molding a medical tube.

  In order to achieve the above-mentioned object, the structural features of the extrusion mold according to the present invention include a mold body in which a tapered conical outer peripheral side recess penetrating from the rear part to the front part is formed, and the mold body A tapered cylindrical outer surface that is installed in the outer peripheral recess and forms an outer peripheral channel between the inner peripheral surface of the outer peripheral recess and a tapered conical inner recess that penetrates from the rear to the front. Provided from the mandrel and the inner mandrel installed in the inner peripheral recess of the outer mandrel to form the inner peripheral flow path between the inner peripheral surface of the inner peripheral recess and from the outer peripheral surface of the mold body to the outer peripheral recess The outer layer injection hole for injecting the outer layer molding material into the outer peripheral side flow path, and the inner layer molding provided from the outer peripheral surface of the mold body through the outer mandrel to the inner peripheral side confronting the outer layer injection hole An inner layer injection hole for injecting material into the inner circumferential flow path; A tube shape forming section having a tube forming flow path for joining the outer peripheral flow path and the inner peripheral flow path at the front portion of the mold body to form an outer layer molding material and an inner layer molding material in a medical tube; The extrusion mold has a tube shape from the outer layer injection hole and the inner layer injection hole by sequentially branching the outer peripheral side channel and the inner peripheral side channel from the upstream side to the downstream side. In addition to shortening the length to the formation part, the volume of the outer peripheral side flow path and the inner peripheral side flow path is reduced.

  In the extrusion mold configured as described above, the outer peripheral side channel extending from the outer layer injection hole toward the tube molding channel of the tube shape forming part and the inner layer injection hole from the inner layer injection hole to the tube molding channel of the tube shape forming part. The inner circumferential flow path extending toward the downstream is sequentially branched from the upstream side to the downstream side. In this case, for example, after branching the outer peripheral side channel and the inner peripheral side channel from the upstream end into two channels that extend in directions opposite to each other in the circumferential direction, In this case, the predetermined portion is extended to the tip side, and the two flow paths are further branched into two flow paths extending in directions opposite to each other in the circumferential direction. For this reason, the axial length from the outer layer injection hole and the inner layer injection hole to the tube shape forming portion can be shortened, and the volumes of the outer peripheral flow path and the inner peripheral flow path can be decreased. .

  That is, in order to smoothly and rapidly change the volume ratio of the outer layer molding material and the inner layer molding material, shortening the length from the outer layer injection hole and the inner layer injection hole to the tube shape forming portion, The present inventors have found through various experiments and the like that it is effective to reduce the volume of the outer peripheral side channel and the inner peripheral side channel. For this reason, the present invention provides a tube shape forming section from the outer layer injection hole and the inner layer injection hole by sequentially branching the outer peripheral side flow channel and the inner peripheral side flow channel from the upstream side to the downstream side. Is shortened to the limit, and the volumes of the outer peripheral flow path and the inner peripheral flow path are reduced. Also, the outer layer injection hole and the inner layer injection hole face each other, that is, on both side portions of the mold body. In this case, the axial direction of the outer layer injection hole and the inner layer injection hole is the same. It is preferable to be located on the line.

  In addition, another structural feature of the extrusion mold according to the present invention is that the outer peripheral side flow path and the inner peripheral side flow path are divided into a part and a peripheral part extending in directions opposite to each other in the circumferential direction. A branch portion composed of a portion extending substantially perpendicular to the direction and extending downstream, and a downstream end portion extending in a spiral shape from each downstream end of the branch portion and then continuing in the circumferential direction. According to this, in addition to sequentially branching the outer peripheral side channel and the inner peripheral side channel from the upstream side to the downstream side, after extending spirally from each downstream end of the branch portion, the circle By providing a downstream end portion that is continuous in the circumferential direction, the overall length from the outer layer injection hole and the inner layer injection hole to the tube shape forming portion is shortened, and the outer and inner flow paths are reduced. The overall volume can be reduced.

  Still another structural feature of the extrusion mold according to the present invention is that the branch portion of the outer peripheral side flow path is provided in a range within one round in the circumferential direction of the outer peripheral surface of the outer mandrel, and the inner peripheral side flow The road branching portion is provided in a range within one round in the circumferential direction of the outer peripheral surface of the inner mandrel. According to this, the outer peripheral side flow path and the inner peripheral side flow path having a suitable shape and length can be formed. In addition, the circumferential length of the branch portion between the outer peripheral side channel and the inner peripheral side channel is set between the outer circumferential surface of the outer mandrel and the outer circumferential surface of the inner mandrel between one half and one circumferential cycle. Is preferred.

  In addition, the structural features of the extrusion apparatus according to the present invention include the above-described extrusion mold, and an extruder having a screw connected to each of the outer layer injection hole and the inner layer injection hole. The amount of injection of the outer layer molding material and the inner layer molding material can be changed by adjusting the screw rotation ratio. According to this, the injection amount of the outer layer molding material and the inner layer molding material can be accurately controlled.

  Further, the medical tube according to the present invention is characterized in that it includes an outer layer molding material and an inner layer molding material which are molded using the above-described extrusion molding apparatus and have different characteristics at the front end side portion and the rear end side portion. At the same time, the boundary transition portion is composed of an outer layer made of an outer layer molding material whose volume ratio gradually changes and an inner layer made of an inner layer molding material.

  According to this, the tip side portion and the rear end side portion are composed of an outer layer molding material and an inner layer molding material having different properties such as hardness, and the boundary transition portion has a volume ratio between the outer layer molding material and the inner layer molding material. A medical tube comprising an outer layer and an inner layer that change smoothly can be obtained in which the length of the transition portion is shortened. In this case, the front end side portion and the rear end side portion may be composed of completely different molding materials, or one of them includes a slight inner layer molding material in the outer layer molding material, and the other is The inner layer molding material may contain a small amount of the outer layer molding material.

1 shows a medical tube molded according to an embodiment of the present invention, wherein (a) is a side view, (b) is a front view, (c) is a rear view, and (d) is a dd of (a). It is sectional drawing. It is sectional drawing of an extrusion mold. FIG. 6 is a cross-sectional view of the outer mandrel. It is an expanded view of the outer peripheral surface of an outer side mandrel. It is sectional drawing of an inner side mandrel. It is an expanded view of the outer peripheral surface of an inner side mandrel. It is a front view of a land part. The bushing is shown, (a) is a front view, (b) is bb sectional drawing of (a).

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a medical tube 10 according to the embodiment. This medical tube 10 is composed of a substantially cylindrical molded body made of soft polyurethane, one side (right side of FIG. 1A) is composed of a soft portion 11, and the other side (FIG. 1A). ) Is formed of a hard portion 12 that is slightly harder than the soft portion 11. A transition portion 13 having a short axial length is formed between the soft portion 11 and the hard portion 12. A partition wall portion 11a (see FIG. 1B) that bisects the inside of the soft portion 11 is formed along the axial direction inside the soft portion 11, and a partition wall portion that bisects the inside of the hard portion 12 inside the hard portion 12. 12a (refer FIG.1 (c)) is formed along the axial direction.

  The transition portion 13 is composed of two layers in which the outer peripheral cylindrical portion is composed of a soft outer layer 13a and a hard inner layer 13b, and a partition wall portion 13c that is formed along the axial direction and bisects the transition portion 13 is composed of a hard portion. ing. FIG. 1D shows a cross section of the central portion of the transition portion 13 in the axial direction. In addition, although not shown in figure, the thickness of the outer layer 13a becomes thicker than the state shown in FIG.1 (d), and the thickness of the inner layer 13b becomes thinner than the state shown in FIG.1 (d). Then, the outer layer 13a bites into the center side in the thickness direction of the partition wall 13c from the left and right sides of the partition wall 13c toward the center. Moreover, the thickness of the outer layer 13a becomes thin and the thickness of the inner layer 13b becomes thicker than the state shown in FIG.

  The partition wall portion 11a, the partition wall portion 13c, and the partition wall portion 12a extend continuously, whereby two flow paths 14a and 14b for passing a liquid such as a chemical solution are formed inside the medical tube 10. Yes. The medical tube 10 has, for example, an outer diameter of 4.13 mm, an inner diameter of 3.43 mm, partition wall portions 11a, 13c, and 12a having a thickness of 0.37 mm, and the transition portion 13 having an axial length of 20 to 30 mm. Is set. As will be described later, a slight amount of hard material is included on the inner peripheral side of the soft portion 11 and a slight amount of soft material is included on the outer peripheral side of the hard portion 12, but the layer made of these is extremely thin. Therefore, in FIG. 1B, a layer made of a hard material is omitted, and in FIG. 1C, a layer made of a soft material is omitted.

  The medical tube 10 configured as described above is formed by using an extrusion molding apparatus including the extrusion mold 20 shown in FIG. Can be obtained. The extrusion mold 20 includes a corner body 21 as a mold body according to the present invention, an outer mandrel 22 installed in the corner body 21, an inner mandrel 23 installed in the outer mandrel 22, and a corner body 21. A bushing 24 provided in the center of the front portion of the horn body 21, and a bushing presser 25 provided over the front surface of the square body 21 and the outer peripheral side of the front surface of the bushing 24.

  The rectangular body 21 is formed of a substantially rectangular block body, and has an outer peripheral recess 21a having a circular cross section and a tapered shape (substantially conical) from the center of the rear end surface toward the center of the front end surface. A material supply port 26 is formed slightly on the rear side of one of the outer peripheral surfaces of the corner body 21 (upper side in FIG. 2), and more than the center of the other outer peripheral surface of the corner body 21 (lower side in FIG. 2). A material supply port 27 is formed slightly on the rear side. An outer layer injection hole 26a extends from the material supply port 26 toward the outer peripheral recess 21a, and an inner layer injection hole outer portion 27a extends from the material supply port 27 toward the outer peripheral recess 21a. The outer layer injection hole 26a and the inner layer injection hole outer portion 27a are arranged so that their central axes are located on the same line. Further, a concave portion 21 b for installing the bushing 24 is formed in the center of the front surface of the corner body 21.

  As shown in FIG. 3, the outer mandrel 22 is formed in a substantially cylindrical shape with a taper, and a tapered inner peripheral side recess 22 a is formed with a circular cross section from the center of the rear end surface toward the center of the front end surface. ing. A flange-shaped fixed portion 22b is formed at the peripheral edge of the rear end of the outer mandrel 22, and the outer mandrel 22 has a large part of the outer peripheral surface and the front surface of the fixed portion 22b on the outer peripheral side of the rectangular body 21. It is installed in the outer peripheral side concave portion 21a of the square body 21 in a state of being in close contact with the inner peripheral surface and the rear end surface of the concave portion 21a. Further, as shown in FIG. 4 (development of the outer peripheral surface), an outer peripheral channel groove 28 is formed on the outer peripheral surface of the outer mandrel 22. The upstream end (the left end in FIGS. 2 to 4) of the outer peripheral channel groove 28 is positioned below the outer layer injection hole 26 a, and the downstream end of the outer peripheral channel groove 28 is at the tip of the outer mandrel 22. positioned.

  The outer circumferential channel groove 28 is located upstream and has an elliptical material receiving recess 28a that is longer in the front-rear direction than the circumferential direction, and a branch that branches into a plurality of channels as it goes downstream from the material receiving recess 28a. A portion 28b and a downstream end portion 28c composed of a spiral portion and a ring-shaped portion that extend in a spiral shape downstream of each downstream end of the branch portion 28b and are continuous in the circumferential direction. The branching portion 28b of the outer circumferential side channel groove 28 is first branched from the downstream end of the material receiving recess 28a by 90 degrees on the opposite side in the circumferential direction when viewed from the front (as viewed from the right side in FIG. 3). After forming the two flow paths extending to the angle, each flow path slightly extends toward the distal end side of the outer mandrel 22.

  Next, after each flow channel is branched to form two flow channels extending to an angle of 45 degrees on the opposite side in the circumferential direction, each of the four flow channels extends slightly to the tip side of the outer mandrel 22. . A downstream end portion 28c is formed on the downstream side of the four flow paths and extends in a spiral shape and then continues in the circumferential direction. In FIG. 4, the outer circumferential side channel groove 28 extends so that the downstream side is wider in the circumferential direction than the upstream side. However, in practice, the outer diameter of the outer mandrel 22 is increased from the upstream side. Since it becomes smaller toward the downstream side, the downstream side of each flow path approaches each other while branching. Further, the maximum width in the circumferential direction of the branch portion 28b is 270 degrees in angle.

  An inner layer injection hole inner portion 27b that communicates straight with the inner layer injection hole outer portion 27a is formed in a portion of the outer mandrel 22 that is half-circumferentially circumferential from the upstream end of the material receiving recess 28a. It extends from the outer peripheral surface toward the inner peripheral recess 22a. The inner layer injection hole outer portion 27a and the inner layer injection hole inner portion 27b described above constitute the inner layer injection hole according to the present invention. Moreover, the outer peripheral side flow path A which concerns on this invention is comprised by the outer peripheral side flow path groove 28 and the part which opposes the outer peripheral side flow path groove 28 in the internal peripheral surface of the outer peripheral side recessed part 21a.

  As shown in FIG. 5, the inner mandrel 23 is formed of a tapered substantially conical body, and an inner pressure air supply hole 23 a is formed from the center of the rear end surface toward the front side. A flange-like fixed portion 23b is formed at the rear end peripheral edge portion of the inner mandrel 23. The inner mandrel 23 has a large portion of the outer peripheral surface and the front surface of the fixed portion 23b as the inner periphery of the outer mandrel 22. It is installed in the inner peripheral side recess 22a of the outer mandrel 22 in close contact with the inner peripheral surface of the side recess 22a and the rear end surface of the fixed portion 22b. Further, as shown in FIG. 6 (development view of the outer peripheral surface), an inner peripheral flow channel groove 29 is formed on the outer peripheral surface of the inner mandrel 23. As shown in FIG. 2, the vicinity of the upstream end of the inner circumferential flow path groove 29 (the vicinity of the left end in FIGS. 2, 5 and 6) is located above the inner layer injection hole inner portion 27b. The downstream end of the circumferential channel groove 29 is positioned near the tip of the inner mandrel 23.

  Further, the inner circumferential side channel groove 29 is located upstream and has an elliptical material receiving recess 29a that is longer in the front-rear direction than in the circumferential direction, and branches into a plurality of channels as it progresses downstream from the material receiving recess 29a. The branch portion 29b includes a downstream end portion 29c including a spiral portion and a ring-shaped portion that extend in a spiral shape downstream of each downstream end of the branch portion 29b and are continuous in the circumferential direction. The branch portions 29b of the inner circumferential channel 29 are first branched from the rear end of the material receiving recess 29a in the front view (as viewed from the right side in FIG. 5), and respectively 90 on the opposite side in the circumferential direction. After forming the two flow paths extending to an angle of degrees, each flow path slightly extends to the tip side of the inner mandrel 23.

  Next, after each flow channel is branched to form two flow channels extending to an angle of 45 degrees on the opposite side in the circumferential direction, each of the four flow channels extends slightly to the tip side of the inner mandrel 23. . And the downstream end part 29c continued in the circumferential direction is formed in the downstream of four flow paths. The length in the axial direction of the downstream end portion 29c is slightly longer than the length in the axial direction of the downstream end portion 28c described above. Also in this case, in FIG. 6, the inner circumferential channel groove 29 extends so that the downstream side is wider in the circumferential direction than the upstream side, but in reality, the outer diameter of the inner mandrel 23 is smaller. Since it becomes smaller as it goes from the upstream side to the downstream side, the downstream side of each flow path approaches each other while branching. Also in this case, the maximum width in the circumferential direction of the branching portion 29b is 270 degrees in angle.

  Moreover, the inner peripheral side flow path B according to the present invention is configured by the inner peripheral side flow path groove 29 and the portion of the inner peripheral surface of the inner peripheral side recess 22a facing the inner peripheral side flow path groove 29. The The outer peripheral side flow path A and the inner peripheral side flow path B are merged at the distal end side of the outer mandrel 22 and at the vicinity of the distal end of the inner mandrel 23. That is, a tube inner peripheral surface forming portion 31 is formed on the distal end side of the inner mandrel 23, and the inner mandrel 23 is in a state where the tube inner peripheral surface forming portion 31 protrudes from the distal end opening 22 c of the outer mandrel 22. The outer mandrel 22 is installed in the inner peripheral recess 22a.

  The tube inner peripheral surface forming portion 31 is located on the distal end side of the columnar base portion 31a, the tapered portion 31b which is located on the distal end side of the base portion 31a, the distal end side gradually becoming smaller in diameter than the rear portion, and the distal end side of the tapered portion 31b. And a substantially cylindrical land portion 31c. A slit 31d is formed in the center of the land portion 31c as shown in FIG. In a state where the base 31a is provided with a gap for forming a downstream flow path that is advanced after the outer peripheral flow path A and the inner peripheral flow path B merge with the inner peripheral surface of the outer peripheral recess 21a. The tapered portion 31b and the land portion 31c protrude outward from the outer peripheral recess 21a of the rectangular body 21.

  As shown in FIG. 8, the bushing 24 is composed of a rear flange portion 24a and a front cylindrical portion 24b. The flange portion 24a is arranged in the concave portion 21b of the corner body 21 so as to form a corner. It is assembled to the body 21. An outer peripheral surface forming recess 24c having a circular cross-sectional shape from the center of the rear end surface to the center of the front end surface is formed in the flange-shaped portion 24a. An outer peripheral surface forming recess 24d having the same diameter is formed in communication with the outer peripheral surface forming recess 24c.

  And the taper part 31b of the tube inner peripheral surface formation part 31 is arrange | positioned in the outer peripheral surface formation recessed part 24c in the state which provided the clearance gap between the inner peripheral surface of the outer peripheral surface formation recessed part 24c. The land portion 31c of the tube inner peripheral surface forming portion 31 is disposed in the outer peripheral surface forming concave portion 24d with a gap for forming a flow path between the inner peripheral surface of the outer peripheral surface forming concave portion 24d. Yes. The gap between the inner peripheral surface of the outer peripheral surface forming recess 24c and the outer peripheral surface of the tapered portion 31b of the tube inner peripheral surface forming portion 31 is a softer soft material sent from the outer peripheral flow path A, the inner peripheral side The hard material harder than the soft material sent from the flow path B, or the soft material and the hard material are narrowed down to the thickness of the medical tube 10.

  And the clearance gap between the inner peripheral surface of the outer peripheral surface formation recessed part 24d and the outer peripheral surface of the land part 31c of the tube inner peripheral surface formation part 31 makes a predetermined thickness and sends out a soft material or a hard material outside. In this case, the outer peripheral surface of the medical tube 10 is formed by the inner peripheral surface of the outer peripheral surface forming recess 24d, and the inner peripheral surface of the medical tube 10 is formed by the outer peripheral surface of the tube inner peripheral surface forming portion 31 and the inner surface of the slit 31d. And partition part 11a, 13c, 12a is formed. In addition, the soft material mentioned above comprises the outer layer forming material of this invention, and a hard material comprises the inner layer forming material of this invention. Further, the tube forming flow path C according to the present invention includes the tube inner peripheral surface forming portion 31 and the front portion of the corner body 21 and the bushing 24 having the inner peripheral surface facing the outer peripheral surface of the tube inner peripheral surface forming portion 31. Is formed.

  The bushing presser 25 is composed of a circular plate with a circular hole 25a formed in the center. The bushing presser 25 is placed on the front side of the flange-shaped part 24a of the bushing 24 with the cylindrical part 24b being inserted into the hole 25a. is set up. Although not shown, the bushing presser 25 is fixed to the corner body 21 by bolts, and the bushing 24 is thereby fixed in the recess 21 b of the corner body 21. The fixed portion 23b of the inner mandrel 23 is fixed to the fixed portion 22b of the outer mandrel 22 by bolts 32a and 32b, and the fixed portion 22b of the outer mandrel 22 is fixed to the square body 21 by bolts (not shown). Has been.

  In the present embodiment, for example, when the inner diameters of the outer layer injection hole 26a, the inner layer injection hole outer portion 27a, and the inner layer injection hole inner portion 27b are 5 to 10 mm, the outer layer injection hole 26a and the inner layer injection hole outside The length from the central axis of the portion 27a and the inner layer injection hole inner portion 27b to the tip of the tube inner peripheral surface forming portion 31 is about 30 to 60 mm. According to this, the medical tube 10 in which the length of the transition part 13 is short can be formed in response to the soft material or the hard material sensitively to the injection speed of the soft material or the hard material.

  Although not shown, the extrusion molding apparatus to which the extrusion mold 20 is attached connects the extrusion mold 20 and the extrusion molding apparatus, and a soft material is supplied from the material supply port 26 to the outer layer injection hole 26a side. Adapter for feeding, adapter for feeding hard material from the material supply port 27 to the inner layer injection hole side, heating cylinder for heating the molding material fed to the material supply ports 26, 27, screw installed in the heating cylinder, extrusion mold Various devices and mechanisms necessary for performing extrusion molding using the extrusion mold 20 are provided, such as a control device for controlling the respective devices provided around 20. A heater or a cooling water channel can be installed using the hole 23a of the inner mandrel 23.

  When the medical tube 10 is formed using the thus configured extrusion molding apparatus, first, after the extrusion mold 20 is heated to an appropriate temperature, each material inlet (not shown) is inserted. The supplied soft material and hard material are heated by each heating cylinder. Next, the soft material is fed by the rotation of the screw for feeding the soft material, and filled into the outer layer injection hole 26a through the adapter. In this case, the screw for feeding the hard material is also rotated at the lowest rotational speed. As a result, the hard material is fed in a very small amount by the rotation of the screw for feeding the hard material, and is filled in the inner layer injection hole through the adapter.

  Further, the soft material is sent out, and the soft material is moved into the outer peripheral side flow path A from the outer layer injection hole 26a. At this time, after the soft material flows from the material receiving recess 28a of the outer peripheral flow path A to the branching section 28b and branches into a plurality of flow paths, it continues in a ring shape at the downstream end 28c. Further, the hard material moves into the inner circumferential flow path B from the inner layer injection hole. At this time, after the hard material flows from the material receiving recess 29a of the inner peripheral flow path B to the branching part 29b and branches into a plurality of flow paths, it continues in a ring shape at the downstream end part 29c.

  Further, the soft material and the hard material move to the tube forming flow path C formed by the bushing 24 and the tube inner peripheral surface forming portion 31. Thereby, the cylindrical soft material is deformed to a thickness slightly larger than the set thickness of the medical tube 10 by including a very small amount of hard material on the inner peripheral side. The soft material and the hard material are a medical tube having a set thickness after being cooled and contracted in the radial direction after being pushed out from the tip of the tube forming channel C while maintaining its shape. Ten soft portions 11 are formed. During this extrusion molding, the soft material is heated to an appropriate temperature and gradually deforms from the outer layer injection hole 26a through the outer peripheral flow path A to the tube forming flow path C. It will be formed without difficulty.

  Next, while gradually decreasing the rotational speed of the soft material delivery screw, the rotational speed of the hard material delivery screw is gradually increased. As a result, the soft material moves from the outer layer injection hole 26a into the outer peripheral flow path A while gradually decreasing the injection amount. Further, the hard material moves from the inner layer injection hole into the inner circumferential flow path B while gradually increasing the injection amount. In the tube forming channel C, the soft material and the hard material are formed into a two-layered cylindrical body composed of an outer layer and an inner layer while gradually changing the ratio. The two-layered cylindrical body is cooled to the transition portion 13 of the medical tube 10 after being pushed out from the tube forming channel C while maintaining its shape.

  At this time, in addition to the small volumes of the outer peripheral side flow path A and the inner peripheral side flow path B, the length from the outer layer injection hole 26a and the inner layer injection hole inner portion 27b to the tip of the tube forming flow path C is Since it is short, when the rotational speed of each screw is changed, the injection amount of the soft material and the hard material responds sensitively to the rotational speed. For this reason, the length of the transition part 13 can be shortened as much as possible. Next, when the rotational speed of the screw for feeding the soft material becomes the lowest speed and the rotational speed of the screw for feeding the hard material becomes high, the rotational speeds of both screws are made constant. Thereby, the hard portion 12 including a slight soft material is formed on the outer peripheral side of the cylindrical hard material. And the obtained medical tube 10 consists of the soft part 11, the transition part 13, and the hard part 12, and becomes a molded article with a favorable dimensional accuracy.

  As described above, in the extrusion mold 20 according to the present embodiment, the outer peripheral side channel A extending from the outer layer injection hole 26a toward the tube molding channel C and the inner layer injection hole toward the tube molding channel C are provided. The inner peripheral side flow path B extending in this manner is sequentially branched from the upstream side to the downstream side. And the outer peripheral side flow path groove 28 constituting the outer peripheral side flow path includes a branch portion 28b that branches into a plurality of flow paths, and a downstream end that extends in a spiral shape downstream of the branch portion 28b and continues in the circumferential direction. The inner circumferential side channel groove 29 that is configured by the portion 28c and that constitutes the inner circumferential side channel is formed by a branching portion 29b that branches into a plurality of channels and a spiral extension downstream of the branching portion 29b. It is comprised by the downstream end part 29c continued in the circumferential direction.

  Therefore, the length from the outer layer injection hole 26a and the inner layer injection hole to the tube forming flow path C can be shortened, and the volumes of the outer peripheral side flow path A and the inner peripheral side flow path B can be reduced. it can. As a result, the volume ratio between the soft material and the hard material can be changed smoothly and rapidly, and the length of the transition portion 13 can also be shortened.

  Further, since the branching portion 28b of the outer circumferential side flow channel groove 28 and the branching portion 29b of the inner circumferential side flow channel groove 29 are provided within a range of 270 degrees in the circumferential direction of the outer mandrel 22 and the inner mandrel 23, a suitable shape And the outer peripheral side flow path A and the inner peripheral side flow path B having a length can be formed. Moreover, the extrusion molding apparatus according to the present embodiment connects heating cylinders (extruders according to the present invention) each having a screw to the material supply ports 26 and 27 side of the extrusion mold 20, and screws for each heating cylinder. The injection amount of the soft material and the hard material can be changed by adjusting the rotation ratio. According to this, the injection amount of the soft material and the hard material can be accurately controlled.

  Further, according to the extrusion molding apparatus according to the present embodiment, the front end side portion and the rear end side portion are composed of the soft portion 11 and the hard portion 12 having different hardnesses, and the soft outer layer 13a and the hard inner layer therebetween. It is possible to obtain a medical tube 10 having a short transition portion 13 formed of 13b and smoothly changing its volume ratio. According to this medical tube 10, the soft portion 11 is placed in the back of the patient's body to reduce irritation to the patient's body, and the hard portion 12 is extended outside the patient's body to facilitate operation and is not easily crushed. You can do it. Moreover, since the inside of the transition portion 13 is hard and the surface is soft, it is possible to reduce irritation to the patient while strengthening the waist. In addition, the extrusion molding apparatus according to the present embodiment uses a device that varies the rotation ratio of the screw, not the opening and closing of the flow path such as a valve, in order to control the injection amount of the molding material. Highly accurate molding can be performed.

  Further, the medical tube and the extrusion mold according to the present invention are not limited to the above-described embodiments, and can be appropriately changed within the technical scope of the present invention. For example, in the above-described embodiment, the medical tube is the medical tube 10 including the two flow paths 14a and 14b. However, the medical tube includes a single flow path that does not include the partition wall 11a. Tubes for medical use or medical tubes having three or more flow paths may be used. Furthermore, the soft thermoplastic resin constituting the medical tube is not limited to polyurethane, and other materials such as polyvinyl chloride can also be used. Moreover, the color of hard material and soft material can be made different so that they can be distinguished.

  Furthermore, in the embodiment described above, the characteristic of the molding material is hardness, but other characteristics may be used. For example, the inner layer of the medical tube can be made of a material having high lubricity such as polypropylene and the outer layer can be made of a soft olefin elastomer in order to improve the passage of the guide wire. Further, the inner layer of the medical tube can be composed of an aromatic polyurethane having chemical resistance, and the outer layer can be composed of an aliphatic polyurethane having a property of being softened by body temperature. Furthermore, the inner layer and the outer layer of the medical tube can be configured by combining molding materials having various other characteristics. Moreover, it cannot be overemphasized that the transition part of the medical tube which concerns on this invention may be provided not only in the intermediate part of the longitudinal direction of a medical tube but in either side.

  DESCRIPTION OF SYMBOLS 10 ... Medical tube, 11 ... Soft part, 12 ... Hard part, 13 ... Transition part, 13a ... Outer layer, 13b ... Inner layer, 20 ... Extrusion mold, 21 ... Square body, 21a ... Outer peripheral side recessed part, 22 ... Outer side Mandrel, 22a ... Inner peripheral side recess, 23 ... Inner mandrel, 24 ... Bushing, 24c, 24d ... Outer peripheral surface forming recess, 26a ... Outer layer injection hole, 27a ... Inner layer injection hole outer side, 27b ... Inner layer injection hole inner side , 28 ... outer peripheral side flow channel, 28 b and 29 b ... branching portion, 28 c and 29 c ... downstream end, 29 ... inner peripheral side flow channel, 31 ... tube inner peripheral surface forming part, A ... outer peripheral side flow Road, B ... inner peripheral flow path, C ... tube forming flow path.

Claims (5)

A mold main body formed with a tapered conical outer peripheral side recess penetrating from the rear part to the front part;
An outer peripheral flow path is formed between the outer peripheral side concave portion of the mold body and the inner peripheral surface of the outer peripheral concave portion, and a tapered conical inner peripheral concave portion penetrating from the rear portion to the front portion is formed. A tapered cylindrical outer mandrel;
An inner mandrel that is installed in an inner peripheral recess of the outer mandrel and forms an inner peripheral flow path with an inner peripheral surface of the inner peripheral recess,
An outer layer injection hole for injecting an outer layer molding material into the outer peripheral flow path, which is provided from the outer peripheral surface of the mold body to the outer peripheral recess,
Inner layer injection for injecting an inner layer molding material into the inner peripheral flow path provided from the outer peripheral surface of the mold main body through the outer mandrel to the inner peripheral recess, facing the outer layer injection hole. Holes,
A tube shape having a tube forming channel that forms the outer layer molding material and the inner layer molding material in a medical tube by joining the outer peripheral channel and the inner peripheral channel at the front portion of the mold body. An extrusion mold comprising a forming part,
By sequentially branching the outer peripheral flow path and the inner peripheral flow path from the upstream side to the downstream side, the outer layer injection hole and the inner layer injection hole to the tube shape forming portion An extrusion mold characterized by shortening the length and reducing the volume of the outer peripheral flow path and the inner peripheral flow path.   A bifurcating portion comprising a portion extending in a direction in which the outer circumferential side flow channel and the inner circumferential flow channel are branched to become opposite to each other in the circumferential direction, and a portion extending substantially downstream in the circumferential direction and extending downstream. The extrusion mold according to claim 1, wherein the extrusion mold is configured to extend in a spiral shape from each downstream end of the branch portion and then to a downstream end portion continuous in a circumferential direction.   The branch portion of the outer peripheral side channel is provided in a range within one round in the circumferential direction of the outer peripheral surface of the outer mandrel, and the branch portion of the inner peripheral channel is arranged in the circumferential direction of the outer peripheral surface of the inner mandrel. The extrusion mold according to claim 2 provided in the range.   It is an extrusion molding apparatus provided with the extrusion mold of Claim 1 thru | or 3, Comprising: The extruder provided with the screw was respectively connected to the said injection hole for outer layers, and the said injection hole for inner layers, The screw of both extruders An extrusion apparatus capable of changing an injection amount of the outer layer molding material and the inner layer molding material by adjusting a rotation ratio.   The molding is performed using the extrusion molding apparatus according to claim 4, and the front end side portion and the rear end side portion are composed of the outer layer molding material and the inner layer molding material having different characteristics, and a transition portion of the boundary is gradually formed. A medical tube comprising an outer layer made of the outer layer molding material and a inner layer made of the inner layer molding material, the volume ratio of which changes.

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